DE20211612U1 - Autostereoscopic projection arrangement - Google Patents

Description

u.C.: GM 3DProjection0702 Jena, July 12, 2002

4D Vision GmbH

Löbstedter Straße

07749 Jena

* * * Autostereoscopic projection arrangement

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4D-Vision GmbH Jena, July 12, 2002

o.Z.: GM 3DProiektion0702

Autostereoscopic projection arrangement

The invention relates to autostereoscopic projection arrangements.

Such an arrangement is described, for example, in DE 206474. This document discloses a projection screen that has a line grid in front of and behind a ground glass screen in the viewing direction. The line grids contain narrow, vertically aligned, alternately opaque and transparent lines through which a stereo image pair is projected at the back. The viewer(s) look through a line grid on the front and experience a spatial visual impression, as the viewer's eyes are presented with different perspectives. The disadvantage of this arrangement is that slightly incorrect adjustments of the line grid or the ground glass screen lead to unpleasant phenomena such as moiré effects.

US 5,146,246 describes a two-view projection. In this arrangement, each viewer's eye is essentially presented with only one view, either the right or the left. Here, too, a line grid, i.e. a barrier screen, is arranged in front of and behind the projection screen in the viewing direction. This barrier screen is again disclosed as comprising vertical opaque and transparent strips. US 5,225,861 by the same inventor shows a similar arrangement. This is a rear projection system which projects a left and a right image through a grid with opaque and transparent elements, whereby the viewer's eyes are presented with essentially disjoint images due to a further grid with opaque and transparent elements.
views are visible. The font also describes vertical opaque and transparent stripes as grid elements.

For the latter documents, the corresponding arrangements require a great deal of adjustment effort. In addition, the additionally described image separation means are only essentially suitable for systems with two displayed views, so that the viewer is hardly given any freedom of movement during stereoscopic perception.

The publication JP 9179090 describes a rear projection system with a lenticular in which at least two views of a scene are displayed time-multiplexed

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4D-Vision GmbH Jena, July 12, 2002

o.Z.: GM 3DProjection0702

The rear-projected views are assigned to the strip sections on the projection screen, which correspond to the image directions of the lenticulars, via controllable liquid crystal sections. These sections are either transparent or scattering, so that depending on their state, a view is always projected through the lenticulars in one or more defined directions. The disadvantage of this arrangement is the high material expenditure. Above all, a high level of control electronics is required. Furthermore, despite the views being displayed in full resolution using time multiplexing, the viewer only sees one image at a reduced horizontal resolution per eye. The arrangement also requires fast projection imagers for flicker-free display. The frame rate of these imagers must be higher the more views are to be displayed, which makes the arrangements even more expensive.

US 4,101,210 and US 4,132,468 describe a stereo projection for several views of a scene, whereby continuous and non-overlapping, line-structured raster images of several views are formed on a screen (e.g. an emulsion) due to the imaging measures. These raster images have virtually no gaps, i.e. the view parts are shown close to one another. The said imaging measures include in particular the use of lens grids in combination with lenticulars.

Document DE 3529819 C2 describes a projection of several views through a lenticular. In this arrangement, the adjacent cylindrical lenses are used to project the strips of views under each individual cylindrical lens. The advantage of this is that the projector housings do not have to be particularly narrow in order to achieve the correct combination of views on the projection screen. The disadvantage here is that large-format lenticulars are required, particularly for large screen diameters.

DE 19608305 A1 discloses a rear projection system, whereby two views are projected onto a screen through vertical barrier strips. The resulting raster image from the two views is then made visible to the viewer through a barrier screen in such a way that the viewer's eyes see different views, creating a spatial impression. The arrangement is characterized by a sliding mechanism that moves the viewer-side barrier screen depending on the position of the eye.

4D-Vision GmbH Jena, July 12, 2002

o.Z.: GM 3DProiektion0702

shifts. The disadvantage here is that only two views of a scene are used. Furthermore, the control circuit for determining the eye position and correspondingly shifting the barrier screen on the viewer side has a certain inertia, which means that the viewer sometimes perceives a pseudoscopic image. The arrangement is usually only suitable for one viewer.

A projection device with lenticular is shown in DE 3700525 A1. In this arrangement, the projection surface is curved. One of the disadvantages is the large amount of space required for large-format screens.

WO 98/43441 A1 describes a dynamic multi-view projection system with shutters. The main disadvantage here is the high cost of manufacturing the arrangement.

US 2,313,947 discloses a multi-view projection with two barrier screens comprising vertical barrier strips. US 2,307,276 also describes a multi-view projection with barrier screens using vertical barrier strips, whereby a certain strip width remains dark between the resulting view strips on the screen. This largely avoids pseudoscopic and double image positions.

US 4,872,750 describes a rear projection system with a rear barrier screen, whereby color images are achieved by overlapping separate R, G, and B projections. Lenticulars are preferably used for spatial reconstruction. The disadvantage here is the high level of equipment required.

Patent document DE 195 06 648 criticizes the state of the art of 3D representation for the sudden change in perspective when the viewer moves, which occurs due to the discrete number of views displayed. An autostereoscopic arrangement is described to avoid these disadvantages, in which several views are displayed in observable zones, so that overlapping areas are created between the observation zones and so that the illumination intensity of the individual observation zones is reduced at the edges. Optical imaging devices described include aperture stops, which are each in a transition area.

4D-Vision GmbH · * Jena, July 12, 2002

o.Z.: GM 3DProjection0702

generate overlapping observation zones of two views. The principle underlying this application requires a high level of technical effort, as 3D images with larger dimensions are required.

In the applicant's DE 10003326 C2, autostereoscopic methods and corresponding arrangements are described in which the spatial impression for several viewers is created without the need for any aids by means of a wavelength filter array. The filter array, which is located in front of or behind an image generator, consists of a large number of wavelength filters arranged in rows and columns, each of which is transparent to light of certain transparency wavelengths/ranges and thus specifies discrete wavelength-dependent light propagation directions for the light emitted by the image generator. An image composed of several views of a scene or an object is displayed on the image generator with image elements divided into rows and columns, so that due to the filter array, a viewer sees predominantly different selections of views with both eyes. The disadvantage here is that large-screen projections cannot be easily realized.

Based on this state of the art, the invention is based on the object of developing arrangements of the type mentioned at the beginning in such a way that improved perceptibility is achieved even with larger image dimensions. The aim should preferably be achieved with simple or easily manufactured components. Furthermore, a spatial impression should be made possible for several viewers.

This object is achieved according to the invention by an autostereoscopic projection arrangement comprising:

- at least two projectors,

- a projection screen,

- at least two filter arrays (Fi, F2, .. Fa, ..), wherein at least one filter array (Fi) is arranged between the projection screen and the at least two projectors, i.e. behind the projection screen in the viewing direction, and at least one filter array (F2) is arranged in front of the projection screen in the viewing direction, wherein

- all filter arrays (Fi, F2, .. Fa, ..) have wavelength filter elements arranged in columns and rows which are transparent to light of different wavelengths (λ) or different wavelength ranges (Δλ),

4D-Vision GmbH Jena, July 12, 2002

o.Z.: GM 3DProiektion0702

- by means of the projectors, partial information of η views Ak (with k=l..n; n>2) of a scene or an object is projected through at least one filter array (Fi) onto the projection screen, so that partial information of the views (Ak) is made optically visible on the projection screen in a combination or mixture determined by the arrangement geometry, and the projection screen is divided into a sufficiently resolving grid of image display elements (ay) in columns (i) and rows (j), which, depending on the characteristics of the filter arrays (Fi, F2, .. Fa, ..) and the projectors, each emit light of certain wavelengths (λ) or wavelength ranges, and each image display element (aij) displays partial information(s) of at least one of the views Ak,

- for the light emitted from the projection screen to the viewer, directions of propagation are specified by the at least one filter array (F2) which is arranged in front of the projection screen in the viewing direction, wherein in each case an image display element (o^) corresponds to a plurality of associated wavelength filters of the filter array (F2) or a wavelength filter of the filter array (F2) corresponds to a plurality of associated image display elements (a,j) in such a way that the connecting line between the center of gravity of the cross-sectional area of a visible section of the image display element (aij) and the center of gravity of the cross-sectional area of a visible section of the wavelength filter corresponds to a direction of propagation, so that from each viewing position an observer optically perceives with one eye predominantly partial information of a first selection and with the other eye predominantly partial information of a second selection from the views (Ak), whereby a spatial impression is created for the observer from a plurality of viewing positions.

It is advantageous to use a total of 2, 4, 8, 16, 32 or 40 projectors. Very good spatial impressions with good brightness for several viewers and at the same time pleasant freedom of movement are achieved from around 8 views shown, whereby preferably at least 8 projectors are used to project the views.

Preferably, exactly two filter arrays (Fi) and (F2) are used in the arrangement described above. Special embodiments in which more than two filter arrays are advantageous are described below.

4D-Vision GmbH ·· ·!.·!.· "..* &Ggr; *..*.!.. Jena, July 12, 2002

o.Z.: GM 3DProiektion0702

The wavelength filter elements contained in the wavelength filter arrays can, for example, be transparent to red, green, blue, yellow, cyan or magenta and/or transparent or opaque to the entire visible wavelength range.

Furthermore, the filter elements of the filter arrays (Fi, F2, .. Fa, ..) have any shape, preferably polygonal, particularly preferably rectangular. As a rule, a filter element has an area of approximately a few 10,000 μm ² up to a few square millimeters. Deviations from this are possible depending on the case. The filter element shape and/or size can also vary within a filter array or even within a row or column of one and the same filter array.

The shape of the picture elements on the projection screen depends essentially on the filter arrays on the projector side, so that the above-mentioned variations in the shape or size of the filter elements have an essential influence on the picture elements.

The image created on the projection screen, which is combined from various partial information of the views (Ak), has - depending on the structure of the filter array(s) and the geometric arrangement of the projectors - a grid of image display elements (ay) in columns (i) and rows (j). This grid structure is not necessarily visible. The image display elements (cty) can emit light of very different wavelength ranges - depending on what kind of light from the projectors arrives at the corresponding points on the projection screen. Depending on the design of the invention, small partial areas of the projection screen between the image display elements can also remain without any partial information of any view (Ak), for example because no light from any projector reaches this partial area. Such areas are then not necessarily to be regarded as image display elements (a,j) in the grid (i,j). Such arrangements also produce the result, but are not necessarily preferable.

It is also conceivable that an image display element (aij) displays full-color partial image information, which in particular originates from an optical mixture of partial information from different wavelength ranges. In addition - also depending on the arrangement structure - such an image element can also display partial information simultaneously from different image element positions within a view or even from different views, for example when the light rays arriving on the projection screen from two or more projectors overlap.

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4D-Vision GmbH · Jena, July 12, 2002

o.Z.: GM 3DProjection0702

It is advantageous if each of the filter arrays (Fi, F2, .. Fa, ..) contains wavelength filter elements (ßApq) in a separate, filter array-assigned grid of rows (qA) and columns (Pa), which are arranged on the filter array according to the following function depending on their transparency wavelength/transparency wavelength range (XAb)

= P _A - d _Apq ■ q _A - n _Am ■ IntegerPart

with

- (A) the index of the respective array (Fa).

- (ρα) the index of a wavelength filter (ßA _Pq ) in a row of the respective array (Fa),

- (q _A ) the index of a wavelength filter (ßA _Pq ) in a column of the respective array (F _A ),

- (b) an integer which defines one of the intended transparency wavelengths/wavelength ranges (AAb) for a wavelength filter (ßApq) of the filter array (Fa) at the position (pA,qA) and which can have values between 1 and bAmax,

- (nAm) an integer value greater than zero, which preferably corresponds to the total number (n) of views (Ak) displayed by the projectors,

- (dApq) a selectable mask coefficient matrix for varying the arrangement of the wavelength filters on the respective array (Fa) and

- IntegerPart of a function to produce the largest integer that does not exceed the argument enclosed in square brackets.

The matrix (dA _Pq ) can have real numbers as entries, where in the above equation (Pa) corresponds to the index (p) and (qA) to the index (q) for the matrix (dA _Pq ) and for the filter elements (ß _Apq ), respectively.

Transparency wavelengths/wavelength ranges (k/^) of the same content can also be specified for different (b): For example, if bAmax=8, Xai to Aa3 can stand for R,G,B in this order and _{λ �Mgr;} to Xas for wavelengths outside of visible light, with Xai to Xa3 then transmitting the colors R,G,B and Xa4 to Xas blocking the visible spectrum. The combination rule for a filter (Fa) with the index (A) and for the parameters dA _Pq =-l=const and nAm=8 then provides a filter structure that periodically generates oblique stripes in the RGB colors on an opaque background. Between these colored stripes, five of the filter elements in each row remain opaque. The angle of the inclination of the colored stripes depends on the dimensions of the filter elements (ßApq). Embodiments of the invention are preferred in which
and nAm are equal.

4D-Vision GmbH ··· *··* ' "..".&Idigr;,. Jena, July 12, 2002

o.Z.: GM 3DProjection0702

In a further exemplary embodiment, several of the transparency wavelengths/wavelength ranges X^b can again have the same filter effects: If Äai-Aa7 are wavelength ranges that block the entire visible spectrum, Xas is a filter range that is transparent to the visible spectrum and if nAm=8 and dA _Pq =-l=const, then according to the rule for generating a filter structure, an essentially opaque filter array (Fa) results, which contains oblique, step-shaped transparent strips evenly distributed over the surface, which take up approximately one eighth of the entire surface.

In this context, it is also advantageous if at least two of the filter arrays (Fi, F ₂ ,.. Fa, ..) cannot be made completely congruent by horizontal and/or vertical linear scaling of their structures. In other words: the structures of the corresponding filter arrays do not merge into one another by one- or two-dimensional enlargement or reduction. In relation to the spatial impression, this non-congruence has the effect that from every viewing point, an observer's eye always perceives a mixture of partial information from several views (Ak). The case that an observer's eye sees partial information from exactly one of the views (Ak) is thus completely ruled out.

In addition, such properties of the filter arrays have a special effect: When the viewer moves - assuming suitable arrangement geometries - the structure of a 2D view predominantly seen with one eye can change. For example, it is conceivable that an eye of a viewer at a certain point in the viewing space sees 90% of the perceived image as partial information from view Ai (k=l) and a remaining mixture of 10% of the perceived image as partial information from other views (A _k ) with k>l, whereby the perceived partial information of view Ai (k=l) has a resolution of, for example, 600x400 image elements. Under the conditions mentioned above, the perceived structure of this predominantly seen view Ai (k=l) can now change in a different viewing position so that it has a visible resolution of, for example, 400x600.

Sometimes the filter arrangement can be chosen so that the visible resolution per view is different from that of a single projector.

4D-Vision GmbH · Jena, July 12, 2002

o.Z.: GM 3DProiektion0702

For some applications, it can also be advantageous if at least some of the filter elements of at least one of the filter arrays (Fi, F2, .. Fa, ..) are designed as neutral filters for wavelength-independent attenuation of the light intensity. For example, such filter elements can transmit 0% (opaque), 25%, 50%, 75% or 100% (fully transparent) of visible light, regardless of the wavelength of the light. Such neutral filter elements or grayscale filter elements can be manufactured more cheaply than wavelength filter array elements. In addition, special effects can be achieved using a filter array with neutral filter elements, such as changing the perceived light intensity of one or more views when the viewer moves.

The filter arrays (Fi, F2, .. Fa, ..) are each arranged at a distance (za) in the viewing direction in front of or behind the projection screen. (za) takes on values in the order of magnitude -60 mm < za < 60 mm, where a negative value for (za) means the arrangement in the viewing direction in front of the projection screen and a positive value for (za) means the arrangement in the viewing direction behind the projection screen, each at a distance of the absolute value of (za). In exceptional cases, the absolute value of (za) can also take on values greater than 60 mm, for example if the diagonal of the projection screen is extremely large.

In a further special embodiment, a part of the filter elements of at least one of the filter arrays (Fi, F2, .. Fa, ..) - preferably the filter array which is closest to the viewer(s) - is designed in such a way that said filter elements only transmit light from selected directions of incidence. This can be ensured, for example, by using certain crystals or a polymer coating.
Furthermore, it is conceivable to design at least one filter element of at least one of the filter arrays (Fj, F2, .. F _A , ..) as a lens, preferably as a cylindrical lens, or as a prism, whereby the cylindrical lenses or prisms can also be arranged only in columns or rows. In this way, a comparatively high light transmission is achieved. Such designs are of particular interest in relation to systems with significantly more than 8 displayed views.

While in simple embodiments of the invention each projector projects partial information of only a single view (Ak), e.g. the 2D perspective views of the corresponding

» &ngr;&ngr; V V V VV VV V VVVV VV

4D-Vision GmbH currently: GM 3DProjection0702

Jena, 12 July 2002

representing scenery, it can be advantageous within the meaning of the invention if at least one of the at least two projectors projects a combination image composed of partial information from at least two views (Ak).

In extension of this feature, it sometimes offers advantages if (at least each) two projectors each project a combination image composed of partial information from at least two views (Ak) and the image combination structure of the views (Ak) is selected differently for said two projectors.

For the combination of partial information from several views, reference is made to the applicant's document DE 10003326 C2 cited at the beginning, which provides a rule for general image combination which is similar to the rule used here for structuring the filter arrays.

In some embodiments of the invention, for example when at least one of the projectors is directed at the projection screen at a certain angle, the projected partial information of the views can be projected using a suitable image pre-distortion function, e.g. a trapezoid correction. In this context, modern projectors already offer continuous "Scheimpflug" and/or "Seagull" corrections, which serve to geometrically correct the projected image. If slides are used as projection data, these can also be created with a corresponding pre-correction.

The arrangement according to the invention is particularly efficient in terms of light and area utilization when the alignment and structure of the filter array(s) between the projectors and the projection screen is selected such that each surface element on the projection screen can be exposed to light from at least one of the projectors. This means that no "permanent black spots" are created on the screen, so that each surface element of the projection screen emits partial information from at least one view (Ak). However, as already mentioned above, this advantageous embodiment is not a mandatory requirement for maintaining the functionality of the arrangements according to the invention.

The projection screen is preferably translucent. It can also have a light-concentrating effect, i.e. have a positive "gain". Translucent and light-concentrating

-10- : :

4D-Vision GmbH ·* ··· · *..*.!·, Jena, July 12, 2002

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tractive projection screens are known in the art and therefore require no further explanation for the person skilled in the art.

Excellent sharpness of the image elements on the projection screen is achieved when the projection screen is designed as a very thin disc, preferably with a thickness of less than one millimeter.

In many embodiments of the invention, the projection screen will be a flat plate. Under special circumstances, it may nevertheless be advantageous to make the projection screen curved. In this case, it is advisable to also curve the filter arrays to a corresponding extent.

In general, a separate projection position and projection direction in relation to the projection screen is specified for each projector, whereby the respective projection direction and the respective projection distance preferably vary from projector to projector.
In conjunction with a curved projection screen, for example, this means that the light from the various projectors hits the projection screen at approximately the same angle of incidence. The angle of incidence here is the angle at which the main direction of light propagation of a projected image hits the projection screen.

If all projector lenses are at the same height behind the projection screen, this height should preferably be approximately the height of the center of the projection screen. An appropriately dimensioned mechanical tripod is suitable for ensuring this type of positioning.

The brightness of one or more projectors can sometimes be variably adjusted - within specified limits. This is a feature offered by some modern projectors and can be used to evenly illuminate the projection screen. If, for example, a view of a scene shown is somewhat brighter than the other views for recording reasons, the brightness control of the corresponding projector offers a sufficient remedy.

Examples of projectors that can be used are liquid crystal projectors, DLP/DMD projectors, CRT projectors or slide projectors. Laser projection is also possible, e.g.

4D-Vision GmbH ·· ···&diams; Jena, July 12, 2002

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three lasers as separate RGB imagers. Of course, more than three lasers can also be used.

This list of the types of projectors to be used can be supplemented and does not mean that an arrangement according to the invention cannot also be designed with other types of projectors. Furthermore, different types of projectors can also be used simultaneously within arrangements according to the invention. The differences can relate both to the light modulation principle and to individual parameters such as luminous flux or image resolution.

The projectors are usually supplied with image data by a control electronics, which can also include several separate devices.

In this context, an image data source consisting of one video recorder per projector is conceivable. Each video recorder feeds the associated projector with the image sequence of a view (Ak). The video recorders are linked to one another via a trigger so that all &eegr; views (Ak) are displayed in a synchronized manner.
It is also conceivable to control each projector with its own computer, whereby all computers are synchronized with each other - for example via a network connection. The design using computers enables the application in particular in which at least one projector projects partial information from at least two different views (Ak). For the possible combination of partial information from at least two different views (A _k ), reference is again made to document DE 10003326 C2.

Furthermore, commercially available split computers can also be used to control several projectors simultaneously.

To achieve improved image contrast, an anti-reflection coating can be applied to the filter array closest to the viewer. This prevents extraneous light reflections to a certain extent, which further improves the perceptibility of the spatial image.

Each of the filter arrays (Fi, F2, .. F _A , ..) is designed, for example, as an exposed film, as a printed image or as an optical grating. Other manufacturing variants are conceivable.
Preferably, at least one of the filter arrays (Fi, F2, .. Fa, ..) is laminated onto a substrate, e.g. onto a glass substrate. This allows a good mechanical hold to be achieved.

4D-Vision GmbH ·· ···· Jena, July 12, 2002

o.Z.: GM 3DProjection0702

In another embodiment, it is provided that at least one of the filter arrays (Fi, F2,.. F _A , ..) is arranged within a sandwich structure consisting of several substrates, wherein the substrates optionally each have certain optical properties - such as predetermined refractive indices. The sandwich structure also achieves good mechanical support in conjunction with a long service life of the filter arrays.

A very special embodiment of the invention results from the fact that a reflective surface is located on parts of at least one filter array and this reflective surface is arranged on the side of the filter array(s) facing the projectors and preferably only on the non-transparent filter elements, so that part of the projected light is reflected back into the projectors. If the corresponding projector is able to reuse such light ("transflective projection"), a better degree of light utilization can be achieved.

Further embodiments of the invention provide that at least some of the filter elements of at least one of the filter arrays (Fi, F2, .. Fa, ..) are designed as polarization filters and that at least one of the projectors emits polarized light. The polarization filters can, for example, be transparent for horizontally or vertically linearly polarized light and optionally only transparent for light of certain wavelengths/ranges. A combination of wavelength-independent neutral filters and polarization filter properties is also conceivable in this context. The polarization-dependent transmitting filters only allow the light of those projectors whose light has corresponding polarization properties to pass through.

In an extension of the above-mentioned embodiment, the at least one projector emitting polarized light emits the light in temporally alternating polarization, preferably alternating horizontally linearly and vertically linearly polarized. This achieves a temporal change in the structure of the combination image created on the projection screen.

In general, at least some of the filter elements of at least one of the filter arrays (Fi, F2, .. F _A , ..) can be designed as photochromic or electrochromic optical components. This makes it possible to switch between 2D and 3D projection, namely when the photochromic or electrochromic components in a first state allow the specified wavelength range transmission in order to achieve a spatial

4D-Vision GmbH · · · Jena, July 12, 2002

o.Z.: GM 3DProjection0702

impression ("3D mode"), while in a second state they are largely transparent to virtually the entire visible wavelength spectrum. In the latter state, an almost unaffected projection through the filter elements onto the projection screen is thus ensured. If all filter elements of all existing filter arrays are now brought into this state, a quasi full-resolution 2D perception is possible for the viewer or viewers. While in 3D mode the projectors project at least partial information from two views, in 2D mode exactly one view is shown. In the simplest case, only one projector projects a view in the usual way, whereby image distortion correction may also be used here. In order to improve brightness, several projectors can also project one and the same image onto the projection screen in 2D mode. However, care must be taken to ensure that the respective projector images are projected in such a way that all similar views are perfectly superimposed on the projection screen.
It is also possible to use other optical components, such as photochromic or electrochromic ones. The decisive and essential aspect of the invention for switching between a 2D and a 3D mode is that the optical components in a first state have a defined transparency in certain wavelengths/ranges or, if necessary, in certain transmission levels for wavelength-independent attenuation of the light intensity, while in a second state they have the highest possible transparency for essentially the full visible wavelength spectrum.

In a particularly simple case, which does not require electrochromic filter array elements, the filter arrays are designed to be easily removable from the arrangement according to the invention in order to achieve a 2D projection.

A further embodiment of the arrangements according to the invention provides that at least one of the projectors is covered with a color filter, whereby the light emitted by said projector can only penetrate wavelength filters of the corresponding transparency wavelength or the corresponding transparency wavelength range. This makes it possible to achieve special combination structures of the partial information on the projection screen. It is then possible - for special applications - to achieve a color change in the perceived views even when the viewer moves.

4D-Vision GmbH Jena, July 12, 2002

o.Z.: GM 3DProjection0702

Blending one or more projectors with a color filter can also be implemented in a fundamentally different way, for example with DMD projectors, which project the red, green and blue partial images of a full-color image alternately over time. In this case, blending is not necessary; instead, the projector inherently emits light of different wavelength ranges alternately.

Furthermore, in particular embodiments of the invention, the projectors can be arranged in at least two essentially horizontal rows. This can be achieved on the one hand by influencing the structure of the resulting combined image on the projection screen. On the other hand - insofar as two projectors with their projections essentially lying one above the other emit one and the same image - an increase in the brightness of certain views or parts of views on the combined image that results on the projection screen can be achieved.

A spatial offset between the two rows is also conceivable, for example to arrange the projection lenses horizontally at approximately eye distance, although the projector housings are significantly wider than eye distance.

For ease of use, the arrangement optionally has additional means for automatically aligning the projectors, for example electromechanical actuators. The projectors are then brought into a predetermined position after or during the switch-on process.

The synchronization of the projectors can of course also be carried out manually if necessary. This is preferably done using projected test images with reference marks that are aligned with one another.

The light path of the light emitted by at least one projector can also be folded by using at least one mirror. Folding is a common technical measure, particularly for saving space in optical assemblies.
Here, however, folding can have another advantageous effect: the folded beam path causes light to fall on the projection screen that is not perpendicular to the main direction of light propagation. If the projection screen is designed as a holographic disk, which in particular reflects non-perpendicularly incident light,

: -15-

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4D-Vision GmbH ·· ·· · ·· .... Jena, July 12, 2002

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If the light is transmitted in a concentrated manner (such as the product "HOPS" from Sax3D GmbH/Chemnitz), a brilliant and high-contrast 3D projection image is shown even in daylight.

As mentioned at the beginning, more than two filter arrays (Fi, F ₂ , .. Fa, ..) can be used. It is then advantageous to use three filter arrays, with two preferably located between the projection screen and the projectors and one between the projection screen and the viewers. In this case, the light emitted by the projectors passes through two filter arrays and is therefore particularly strongly structured before it hits the projection screen.

In further design variants, more than three filter arrays can be used.

The object of the invention is also achieved by the following design variant of an autostereoscopic projection arrangement, in this case by an SD front projection arrangement. This comprises:

- at least two projectors,

- a projection screen suitable for front projection,

- a filter array arranged between the projection screen and the at least two projectors, wherein

- the filter array has wavelength filter elements arranged in columns and rows which are transparent to light of different wavelengths (λ) or different wavelength ranges (Δλ) and which absorb the corresponding non-transmitted light at least partially but preferably to a high degree,

- by means of the projectors, partial information of &eegr; views (A _k with k=l..n; n>2) of a scene or an object is projected through the filter array onto the projection screen, so that partial information of the views (Ak) is made optically visible on the projection screen in a combination or mixture determined by the arrangement geometry, and the projection screen is divided into a sufficiently resolving grid of image display elements (ccy) in columns (i) and rows (j), which, depending on the characteristics of the filter array and the projectors, each emit light of certain wavelengths (&lgr;) or wavelength ranges, and each image display element
Represents partial information(s) of at least one of the views (Ak),

4D-Vision GmbH .... Jena, July 12, 2002

o.Z.: GM 3DProjection0702

- for the light emitted from the projection screen on the projection side towards the viewer, directions of propagation are specified by the filter array, wherein in each case an image display element (oty) corresponds to a plurality of associated wavelength filters of the filter array or a wavelength filter of the filter array corresponds to a plurality of associated image display elements (ocij) in such a way that the connecting line between the center of gravity of the cross-sectional area of a visible section of the image display element (ay) and the center of gravity of the cross-sectional area of a visible section of the wavelength filter corresponds to a direction of propagation, so that from each viewing position an observer optically perceives with one eye predominantly partial information of a first selection and with the other eye predominantly partial information of a second selection from the views (Ak), whereby a spatial impression is created for the observer from a plurality of viewing positions.

With such a 3D front projection, the viewer(s) is/are located on the side of the projectors, but they should generally not be in one of the projection beam paths in order to avoid causing shadows.

In this embodiment, the wavelength filter elements contained in the wavelength filter arrays can also be, for example, transparent for red, green, blue, yellow, cyan or magenta and/or transparent or opaque for the entire visible wavelength range.

The image created on the projection screen, which is combined from various partial information of the views (A _k ), has - depending on the structure of the filter array and the geometric arrangement of the projectors - a grid of image display elements (cXy) in columns (i) and rows (j). This grid structure is not necessarily visible. The image display elements (ocij) can emit light of very different wavelength ranges - depending on what kind of light from the projectors arrives at the corresponding point on the projection screen. It is also conceivable that an image display element displays full-color partial image information, which in particular comes from an optical mixture of partial information of different wavelengths/ranges. In addition - also depending on the arrangement structure - such an image element can also

4D-Vision GmbH *··* ··· ···· *··* · *..*.!·· Jena, July 12, 2002 CE: GM 3DProiektion0702

Display partial information from different image element positions within one view (Ak) or even from different views (Ak).

It is also advantageous if the filter array contains wavelength filter elements (ß _pq ) in a grid of rows (q) and columns (p) which are arranged on the filter array according to the following function depending on their transparency wavelength/transparency wavelength range (k _b )

b = pd _p -qn _m - IntegerPart

, with

- (p) the index of a wavelength filter (ß _pq ) in a row of the array,

- (q) the index of a wavelength filter (ß _pq ) in a column of the array,

- (b) an integer which defines one of the intended transparency wavelengthsAwavelength ranges (Xb) for a wavelength filter (ß _pq ) of the filter array at position (p,q) and which can have values between 1 and b _max ,

- (n _m ) an integer value greater than "zero", which preferably corresponds to the total number &eegr; of views displayed by the projectors (Ak),

- (d _pq ) a selectable mask coefficient matrix for varying the arrangement of the wavelength filters on the array and

- IntegerPart of a function to produce the largest integer that does not exceed the argument enclosed in square brackets.

The filter elements of the filter array have any shape, preferably polygonal, particularly preferably rectangular. In special embodiments, several filter arrays (Fa) can also be used between the projectors and the projection screen in this front projection variant, although only one filter array is assumed in the following.

For some applications, it can also be advantageous if at least some of the filter elements are designed as neutral filters for wavelength-independent attenuation of the light intensity. Such neutral filter elements or grayscale filter elements are sometimes cheaper to produce than wavelength filter array elements. In addition, special effects can be achieved by means of a filter array with neutral filter elements.

4D-Vision GmbH *" "··" " '··*«·· Jena, July 12, 2002

o.Z.: GM 3DProjection0702

such as changing the perceived light intensity of one or more views when the viewer moves.

The filter array is arranged at a distance (z) in the viewing direction in front of the projection screen, i.e. on the viewer and projector sides.

Here, (z) takes on values in the order of 0 mm < ζ < 60 mm. In exceptional cases, the magnitude of (z) can also take on larger values, for example if the diagonal of the projection screen is extremely large.

As a rule, the projection screen in this design is designed as a flat plate. However, it is also conceivable for the projection screen to be spatially structured rather than flat. For example, a cylindrical-periodic reflecting surface is advantageous in connection with front projection because the nature of the projection screen alone ensures a certain structured direction of the reflected light.

In a further special embodiment, some of the filter elements are designed in such a way that said filter elements only transmit light from selected directions of incidence. This can be ensured, for example, by using certain crystals or a polymer coating.

It is also conceivable to design at least one filter element as a lens, preferably as a cylindrical lens, or as a prism, whereby the cylindrical lenses or prisms can also be arranged only in columns or rows. In this way, a comparatively high light transmission is achieved. Such designs are of particular relevance in relation to systems with significantly more than 8 views shown.

The object of the invention is further achieved by an autostereoscopic projection arrangement comprising:

- a projector,

- a projection screen suitable for front projection,

- a filter array arranged between the projection screen and the projector, whereby

4D Vision GmbH

o.Z.: GM 3DProiektion0702

Jena, 12 July 2002

- the filter array has wavelength filter elements arranged in columns and rows which are transparent to light of different wavelengths (λ) or different wavelength ranges (Δλ) and which absorb the corresponding non-transmitted light at least partially but preferably to a high degree,

- by means of the projector, partial information from η views (Ak with k=l..n; n>2) of a scene or an object is projected through the filter array onto the projection screen, so that partial information of the views Ak is made optically visible on the projection screen in a combination or mixture determined by the arrangement geometry, and the projection screen is divided into a sufficiently resolving grid of image display elements (a^) in columns (i) and rows (j), which, depending on the characteristics of the filter array and the projector, each emit light of certain wavelengths (λ) or wavelength ranges, and each image display element (ocy) displays partial information(s) of at least one of the views (Ak),

- for the light emitted from the projection screen on the projection side towards the viewer, directions of propagation are specified by the filter array, wherein in each case an image display element (oCy) corresponds to a plurality of associated wavelength filters of the filter array or a wavelength filter of the filter array corresponds to a plurality of associated image display elements (ay) in such a way that the connecting line between the center of gravity of the cross-sectional area of a visible section of the image display element (ay) and the center of gravity of the cross-sectional area of a visible section of the wavelength filter corresponds to a direction of propagation, so that from each viewing position an observer optically perceives with one eye predominantly partial information of a first selection and with the other eye predominantly partial information of a second selection from the views (Ak), whereby a spatial impression is created for the observer from a plurality of viewing positions.

A further solution to the problem is the following autostereoscopic projection arrangement, comprising:

- a projector,

- a translucent projection screen,

- at least two filter arrays (Fi, F ₂ ,.. Fa,..), whereby at least one filter array (Fi) is located between the projection screen and the projector, ie in the viewing direction behind the

-2D-

4D-Vision GmbH Jena, July 12, 2002

o.Z.: GM 3DProiektion0702

projection screen, and at least one filter array (F2) is arranged in front of the projection screen in the viewing direction, wherein

- all filter arrays (Fi, F2, .., Fa,..) have wavelength filter elements arranged in columns and rows which are transparent to light of different wavelengths (λ) or different wavelength ranges (Δλ),

- by means of the projector, partial information from η views (Ak with k=l..n; n>2) of a scene or an object is projected through at least one filter array (Fi) onto the projection screen, so that partial information of the views (Ak) is made optically visible on the projection screen in a combination or mixture determined by the arrangement geometry, and the projection screen is divided into a sufficiently resolving grid of image display elements (cCy) in columns (i) and rows (j), which, depending on the characteristics of the filter arrays (Fi, F2, .. Fa, ..) and the projector, each emit light of certain wavelengths (λ) or wavelength ranges, and each image display element (a^) displays partial information(s) of at least one of the views (Ak),

- for the light emitted from the projection screen towards the viewer, directions of propagation are specified by the at least one filter array (F2) which is arranged in front of the projection screen in the viewing direction, wherein in each case an image display element (oCjj) corresponds to a plurality of associated wavelength filters of the filter array (F2) or a wavelength filter of the filter array (F2) corresponds to a plurality of associated image display elements (oCjj) in such a way that the connecting line between the center of gravity of the cross-sectional area of a visible section of the image display element (oCij) and the center of gravity of the cross-sectional area of a visible section of the wavelength filter corresponds to a direction of propagation, so that from each viewing position an observer optically perceives with one eye predominantly partial information of a first selection and with the other eye predominantly partial information of a second selection from the views (A _k ), whereby a spatial impression is created for the observer from a plurality of viewing positions.

In both of the aforementioned design variants of the autostereoscopic projection arrangements with only one projector, the projector preferably emits light of different wavelengths or wavelength ranges in temporal succession.

: -21-

· ···t

4D Vision GmbH

o.Z.: GM 3DProiektion0702

Jena, 12 July 2002

In addition, the partial information of each of the η views Ak (with k=l..n) is projected in pairs of different wavelengths or wavelength ranges.
This approach can be implemented, for example, by displaying partial information from n=3 views Ak, by using a DMD/DLP projector, and by displaying view Ai (k=1) exclusively in red, view A2 (k=2) exclusively in green, and view A3 (k=3) exclusively in blue. Of course, the color assignments can also be permuted and are not limited to this assignment.
As a result, different colored views are made visible to the viewer(s).

Furthermore, the object of the invention is achieved by an autostereoscopic projection arrangement comprising:

- a translucent projection screen,

- a projector located behind the projection screen in the viewing direction,

- at least one filter array which is arranged in front of the projection screen in the viewing direction, wherein

- the filter array has wavelength filter elements arranged in columns and rows which are transparent to light of different wavelengths (λ) or different wavelength ranges (Δλ),

- by means of the projector, partial information of η views (Ak with k=l..n; n>2) of a scene or an object is projected directly onto the projection screen in a defined combination of the partial information, so that partial information of the views (Ak) is made optically visible on the projection screen, and the projection screen is divided into a sufficiently resolving grid of image display elements (ay) in columns (i) and rows (j), which, depending on the design of the projector, each emit light of certain wavelengths (λ) or wavelength ranges, and each image display element (ay) displays partial information(s) of at least one of the views Ak,

- for the light emitted from the projection screen to the viewer, directions of propagation are specified by the at least one filter array, wherein in each case one image display element (oiy) corresponds to several associated wavelength filters of the filter array or one wavelength filter of the filter array corresponds to several associated image display elements (0^) in such a way that in each case the connecting line between the center of gravity of the cross-sectional area of a visible section of the image display element

4D-Vision GmbH " " * Jena, July 12, 2002

o.Z.: GM 3DProjection0702

(ay) and the centre of gravity of the cross-sectional area of a visible portion of the wavelength filter corresponds to a direction of propagation, so that from each viewing position an observer optically perceives with one eye predominantly partial information of a first selection and with the other eye predominantly partial information of a second selection from the views (Ak), whereby a spatial impression is created for the observer from a multitude of viewing positions.

The combination of the partial information of the views (Ak) which is projected by the projector onto the projection screen is preferably carried out in the manner described in the applicant's DE 10003326 C2. Example image combination rules are also given there.

Corresponding filter arrays, which can be used in connection with this latter embodiment of the invention, for example, are also described in the above-mentioned C2 document.

Otherwise, with regard to the design of the filter elements and the arrangement geometry, essentially the same applies as for the embodiments of the invention mentioned at the beginning.

In this last embodiment, it can be particularly advantageous for compensating imaging errors of the projector lens if the filter elements vary at least partially in their shape.

All the arrangements described so far can also be joined together in a modular design in order to achieve particularly large image diagonals. Furthermore, for special purposes, a lens, preferably a Fresnel lens, can also be placed in front of the arrangements according to the invention, so that a real or virtual image of the autostereoscopic projection device is created for the viewer(s).

All of the described embodiments of the invention allow the stated task to be solved excellently: Autostereoscopic projection devices are disclosed which achieve improved perceptibility even with larger image dimensions. As a rule, simple or easily manufactured components are used. Depending on the arrangement geometry, a spatial impression is made possible for several viewers.

The invention is explained in more detail below with reference to drawings. It shows:

4D-Vision GmbH Jena, July 12, 2002

o.Z.: GM 3DProiektion0702

Fig. 1 is a schematic diagram of the arrangements according to the invention, Fig. 2 is the projector-side filter array of a first embodiment of the invention (detail), suitable for e.g. 8 projectors,

Fig. 3 shows the viewer-side filter array of a first embodiment of the invention (detail), Fig. 4 shows the image structure created on the projection screen in the first embodiment of the invention, which is composed of partial information from different views (detail),

Fig.5 and Fig.6 each show a possible mixture of views that can be seen by an observer’s eye when using the first embodiment of the invention at a viewing position (detail),

Fig.7 the projector-side filter array of a second embodiment of the invention (detail), also suitable for 8 projectors,

Fig.8 the viewer-side filter array of the second embodiment of the invention (detail), Fig.9 the image structure created on the projection screen in the second embodiment of the invention, which is composed of partial information from different views (detail),

Fig. 10 and Fig. 11 each show a possible mixture of views that can be seen by an observer's eye when using the second embodiment of the invention at a viewing position (detail),

Fig. 12 the first projector-side filter array of a third embodiment of the invention (detail), also suitable for 8 projectors,

Fig. 13 the second projector-side filter array of a third embodiment of the invention (detail),

Fig. 14 the viewer-side filter array of the third embodiment of the invention (detail), Fig. 15 the image structure created on the projection screen in the third embodiment of the invention, which is composed of partial information from different views (detail),

Fig. 16 the projector-side filter array of a fourth embodiment of the invention (detail), also suitable for 8 projectors,

Fig. 17 the viewer-side filter array of the fourth embodiment of the invention (detail), Fig. 18 the image structure created on the projection screen in the fourth embodiment of the invention, which is composed of partial information from different views (detail),

4D-Vision GmbH Jena, July 12, 2002

o.Z.: GM 3DProjection0702

Fig. 19 and Fig. 20 each show a possible mixture of views that can be seen by an observer's eye when using the fourth embodiment of the invention at a viewing position (detail),

Fig.21 the projector-side filter array of a fifth embodiment of the invention (detail), which is suitable for a single DMD projector, Fig.22 the viewer-side filter array of the fifth embodiment of the invention (detail), Fig.23 the image structure created on the projection screen in the fifth embodiment of the invention, which is composed of partial information from three different views (detail), wherein the partial information of the different views is reproduced in colors (wavelength ranges) that differ from view to view, and

Fig.24 various usable outlines for filter elements in the arrangements according to the invention.

Fig. 1 shows a schematic diagram of the arrangements according to the invention. The diagram is not to scale.

As described above, the arrangement shown according to the invention comprises the following components:

- at least two projectors (4); (in the drawing, for the sake of clarity, only four are shown, although there could also be eight or more projectors, for example),

- a projection screen (3),

- at least two filter arrays (Fi, F2), wherein the filter array (Fi) is arranged between the projection screen (3) and the projectors (4), i.e. behind the projection screen (3) in the viewing direction of the viewer (5), and the filter array (F2) is arranged in front of the projection screen (3) in the viewing direction of the viewer (5).

As will be explained in more detail below in the individual design variants, all filter arrays (Fi, F2) have wavelength filter elements arranged in columns and rows, which are transparent to light of different wavelengths (λ) or different wavelength ranges (Δλ). In this case, partial information from η views Ak (with k=l..n; n>2) of a scene or an object is projected through at least one filter array (Fj) onto the projection screen (3) by means of the projectors (4), so that partial information of the views (Ak) is displayed on the projection screen (3) in a manner determined by the arrangement.

4D-Vision GmbH ' Jena, July 12, 2002

o.Z.: GM 3DProiektion0702

geometry determined combination or mixture are made optically visible, and the projection screen (3) is divided into a sufficiently resolving grid of image display elements (ay) in columns (i) and rows (j), which, depending on the characteristics of the filter array (Fi) and the projectors (4), each emit light of certain wavelengths (λr;) or wavelength ranges, and each image display element (oCy) displays partial information(s) of at least one of the views (Ak).

For the light emitted from the projection screen (3) to the viewer (5), directions of propagation are specified by the at least one filter array (F2) which is arranged in front of the projection screen (3) in the viewing direction, wherein in each case an image display element (ay) corresponds to a plurality of associated wavelength filters of the filter array (F2) or a wavelength filter of the filter array (F2) corresponds to a plurality of associated image display elements (oc^) in such a way that the connecting line between the center of gravity of the cross-sectional area of a visible section of the image display element (cCy) and the center of gravity of the cross-sectional area of a visible section of the wavelength filter corresponds to a direction of propagation, so that from each viewing position an observer (5) optically perceives with one eye predominantly partial information of a first selection and with the other eye predominantly partial information of a second selection from the views (Ak), whereby a spatial impression is created for the observer (5) from a plurality of viewing positions.

It is advantageous to use a total of 2, 4, 8, 16, 32 or 40 projectors. Very good spatial impressions for several viewers while at the same time allowing for pleasant freedom of movement are achieved with around eight views displayed, whereby at least eight projectors are preferably used to project the views and each projector projects exactly one view (Ak) or partial information from it.

As shown in Fig.l, preferably exactly two filter arrays (Fi) and (F ₂ ) are used in the arrangement described above. Special embodiments in which more than two filter arrays are advantageous are described further below.

In a first exemplary embodiment, an arrangement according to Fig. 1 is used, but eight projectors (4) are used instead of the four shown in the drawing. Each of the eight projectors projects a complete 2D view of the

4D-Vision GmbH Jena, July 12, 2002

u.Z,: GM 3DProjektion0702

scenery/object to be displayed, so that eight views are shown. Such 2D views are, for example, 2D images of a scenery/object that are taken from slightly offset horizontal directions. Due to a technical rasterization, the 2D views are then emitted by the projectors as partial information, for example in a full-color resolution of 800x600 pixels.

The optical axes of the projectors preferably intersect at the center of the projection screen (3), with two adjacent optical axes enclosing an angle of approximately 3.5 degrees. The projectors are aligned accordingly and have a projection distance of, for example, 2900 mm from the center of the projection screen (3). The projectors can advantageously be arranged on a circular path with said center of the surface as the circle center.

All projector lenses are preferably located at the same height behind the projection screen, approximately at the height of the center of the projection screen. An appropriately dimensioned mechanical tripod is suitable for ensuring this type of positioning.

In Fig.2, the projector-side filter array (Fi) of the first embodiment of the invention is shown as a section. This filter array (Fi) contains wavelength filter elements (ßi _pq ) in a grid of rows (q0 and columns (p0), which are arranged on the filter array according to the following function depending on their transparency wavelength/their transparency wavelength range (Au,)

^b - Pa - ^d A _Pq ■ Qa - ⁿ Am ■ integerPart

, with

- the index A=I, since it is the array (Fi),

- (pi) the index of a wavelength filter (ßi _pq ) in a row of the array (Fi),

- (qi) the index of a wavelength filter (ßi _pq ) in a column of the array (Fi),

- (b) an integer which defines one of the intended transparency wavelengths/wavelength ranges (Ku ₃ ) for a wavelength filter (ßi _pq ) of the filter array (Fi) at the position (pi,qO) and can have values between 1 and bi _max ,

- (nim) an integer value greater than zero, which preferably corresponds to the total number (n) of views (Ak) displayed by the projectors,

: -2&Idigr;7- &Ggr;

4D Vision GmbH

o.Z.: GM 3DProiektion0702

Jena, 12 July 2002

- (dipq) a selectable mask coefficient matrix for varying the arrangement of the wavelength filters on the array (Fi) and

- IntegerPart of a function to produce the largest integer that does not exceed the argument enclosed in square brackets.

In the above equation, (pa=Pi) corresponds to the index (p) and (qA=qO to the index (q) for the matrix (dApq=di _pq ) and for the filter elements (ßi _pq ), respectively.

In this embodiment, several of the transparency wavelengthsZ-wavelength ranges (λκ,) have the same filter effects: If λα,γ and λα^,λ^ are wavelength ranges that block the entire visible spectrum, λα,2 is a filter range that is transparent to the visible spectrum, and if ni _m =8 and di _pq =-l=const, then according to the rule for producing a filter structure, an essentially opaque filter array (Fi) results, which contains oblique, step-shaped transparent strips evenly distributed over the surface, which take up approximately one eighth of the entire surface. This is shown in Fig.2. A transparent or opaque filter element here is, for example, approximately 0.285 mm wide and 0.804 mm high. Other designs are of course conceivable.

Fig. 3 shows the viewer-side filter array (F ₂ ) with A=2 of the first embodiment of the invention, also as a section. Similar, but not completely identical parameters are used here as for the filter (FO). These are: &lgr; ₂ ,&igr; and &lgr;2.4..&lgr;2.8 are wavelength ranges that block the entire visible spectrum; &lgr; ₂ ,2 and &lgr; ₂ ,3 are filter ranges that are transparent to the visible spectrum, and n2 _m =8 and d2 _Pq =-l=const. Here too, a transparent or opaque filter element is, for example, approximately 0.285 mm wide and 0.804 mm high, although other dimensions are certainly possible.

The filter array (Fi) is arranged at a distance Zi=2 mm in the viewing direction behind the projection screen. For the array (F2) the distance is Z2=(-)45 mm, whereby this array is located in front of the projection screen. The minus sign means that the array is located in front of the projection screen in the viewing direction.

In order to achieve improved image contrast, an anti-reflection coating is preferably applied to the filter array (F2) that is closest to the viewer. This prevents extraneous light reflections to a certain extent, thereby improving the perceptibility of the spatial image.

4D-Vision GmbH Jena, July 12, 2002

o.Z.: GM 3DProjection0702

If the projectors are aligned as described above, an image structure is created on the projection screen, which is shown in detail in Fig.4. The grid with columns (i) and rows (j) is only shown for the sake of clarity and is of course not necessarily visible on the projection screen (3). In Fig.4, a number in a box corresponds to the view (Ak) from which the partial information comes that is projected onto this grid point on the projection screen. The image created on the projection screen (3), which is combined from various partial information from the views (Ak), therefore has a grid of image display elements (ccy) in columns (i) and rows (j). The image display elements (oCij) can emit light in very different wavelength ranges - depending on what kind of light from the projectors arrives at the corresponding point on the projection screen (3). If DMD/DLP projectors are used in this embodiment, they are full-color image display elements (ocy).
When correctly aligned, the arrangement according to the invention is particularly efficient in terms of light and space utilization, since each surface element on the projection screen can be exposed to light from at least one of the projectors. This means that no "permanent black spots" are created on the screen, so that each surface element of the projection screen emits some partial information of at least some view.

The light propagation directions specified by the filter (F2) ensure that from each viewing position a viewer (5) with one eye predominantly perceives partial information from a first selection and with the other eye predominantly perceives partial information from a second selection from the views (Ak), whereby a spatial impression is created for the viewer (5) from a large number of viewing positions. Fig.5 and Fig.6 each show a possible mixture of views that can be seen by an observer's eye when using the first embodiment of the invention at a viewing position (detail representation). At the first position according to Fig.5, the observer's eye sees predominantly views 2 and 3, for example, while at the second exemplary position according to Fig.6 it predominantly perceives views 6 and 7. If the observer's different eyes now see, for example, the mixtures of views shown, a spatial impression is created.

4D Vision GmbH

o.Z.: GM 3DProiektion0702

Jena, 12 July 2002

It should also be noted that in this first embodiment, the two filter arrays (Fi, F2) cannot be made completely congruent by horizontal and/or vertical linear scaling of their structures. In other words: the structures of the filter arrays do not merge into one another by one- or two-dimensional enlargement or reduction. In relation to the spatial impression, this non-congruence has the effect that from every viewing point, an observer's eye actually always perceives a mixture of partial information from several views (see also the example mixtures of views in Fig.5 and Fig.6). The case where an observer's eye sees partial information from exactly one view from one position in the viewing space is completely excluded.

The projection screen (3) is translucent and preferably also comprises a carrier substrate, e.g. a glass pane. It can also have a light-concentrating effect, i.e. have a positive "gain". Excellent sharpness of the image elements on the projection screen is achieved if the projection screen is designed as a very thin pane, preferably with a thickness of less than one millimeter.

In this first embodiment, the projection screen (3) is a flat plate with a surface diagonal of approximately 50 inches and an aspect ratio of 16:9.

The projectors (4) used are supplied with image data by control electronics, which can also include several separate devices. For example, the control electronics in this context consist of an image data source that contains one video recorder per projector. In other words: there are eight video recorders. Each video recorder feeds a projector - as already mentioned above - with the image sequence of a specific view (Ak). The video recorders are linked to one another via a trigger, so that all eight views (Ak) are displayed in a synchronized manner.

Each of the filter arrays (Fi) and (F2) is designed as an exposed film. Both filter arrays (Fi, F2) are laminated onto a substrate, e.g. a glass substrate. This allows a good mechanical hold to be achieved. In the arrangement according to Fig.l, both filter arrays (Fi, F ₂ ) are always arranged on the side of the glass substrate facing the projectors (4). This achieves the best results, since the beam offsets caused by the substrates are then minimized compared to swapping the filter array sides on the substrates.

· t

4D-Vision GmbH Jena, July 12, 2002

o.Z.: GM 3DProiektion0702

In a second exemplary embodiment, an arrangement according to Fig. 1 is also used, although eight projectors (4) are used instead of the four shown in the drawing. Each of the eight projectors (4) again projects a complete 2D view of the scenery/object to be displayed, so that eight views are shown.

The optical axes of the projectors (4) preferably intersect at the center of the projection screen (3), with two adjacent optical axes enclosing an angle of approximately 3.5 degrees. The projectors (4) are aligned accordingly and have a projection distance of, for example, 2900 mm from the center of the projection screen (3). The projectors (4) can advantageously be arranged on a circular path with the said center of the surface as the circle center.

All projector lenses are located at the same height behind the projection screen (3), approximately at the height of the center of the projection screen (3). To ensure this kind of positioning, an appropriately dimensioned mechanical tripod is suitable.

In Fig.7, the projector-side filter array (Fi) with A=I of the second embodiment of the invention is shown as a section. The wavelength filter elements (ßi _pq ) in the grid of rows (qi) and columns (pi) are arranged according to the rule already described several times, whereby the following parameters were selected here: Let λ&igr;,2..λr; i,8 be wavelength ranges that block the entire visible spectrum, λ&igr;,&igr; a filter range that is transparent to the visible spectrum and let bi _max =8, ni _m =8 and

_ P ₁ - ({^IntegerPart{q _x -1) · \)+ p _x )mod 8)

The function "mod" here denotes the remainder class with respect to a divisor.

A transparent or opaque filter element, for example, is approx. 0.285 mm wide and approx.

0.804 mm high. Other designs are of course possible.

Fig. 8 shows the viewer-side filter array (F2) of the second embodiment of the invention, also as a section. The parameters for generating the corresponding filter structure are: "ki^.X 2,16 are wavelength ranges that block the entire visible spectrum; λ2,&igr; and λ2,2 are filter ranges that are transparent to the visible spectrum, and b2max=16,

4D-Vision GmbH ·* ·····&diams;· ." . ...... Jena, July 12, 2002

o.Z.: GM 3DProjection0702

n2m=16 and d2 _Pq =-l =const. Here, for example, a transparent or opaque filter element is approximately 0.14236 mm wide and 0.804 mm high, although other dimensions are possible.

The filter array (Fi) is arranged at a distance of zi =2 mm behind the projection screen. For the array (F2) the distance is z ₂ =(-)45 mm, whereby this array is located in front of the projection screen in the viewing direction. The minus sign means that the array is located in front of the projection screen in the viewing direction.

In order to achieve improved image contrast, an anti-reflection coating is preferably applied to the filter array (F2) that is closest to the viewer. This prevents extraneous light reflections to a certain extent, thereby improving the perceptibility of the spatial image.

If the projectors are aligned as described above, an image structure similar to that shown in detail in Fig. 9 is created on the projection screen. The grid with columns (i) and rows (j) is only shown for the sake of clarity and is of course not necessarily visible on the projection screen (3). The image created on the projection screen, combined from various partial information from the views (Ak), therefore has a grid of image display elements (oCij) in columns (i) and rows (j). The image display elements ((X ₁ )) can emit light in very different wavelength ranges - depending on what kind of light from the projectors arrives at the corresponding point on the projection screen. If DMD/DLP projectors are used in this embodiment, these are full-color image display elements (ciij).

When correctly aligned, the arrangement according to the invention is particularly efficient in terms of light and area utilization, since each surface element on the projection screen can be exposed to light from at least one of the projectors. This means that no "permanent black spots" are created on the screen, so that each surface element of the projection screen emits some partial information of at least some view (Ak).

The light propagation directions specified by the filter (F2) ensure that from any viewing position a viewer (5) can see with one eye predominantly partial information of a first selection and with the other eye predominantly partial

· · · · · &bull; &bull; ·
· · &bull; · i
· 1
#· · 4

4D Vision GmbH

o.Z.: GM 3DProjection0702

Jena, 12 July 2002

information of a second selection from the views (Ak), whereby a spatial impression is created for the viewer (5) from a multitude of viewing positions. Fig. 10 and Fig. 11 each show a possible mixture of views that can be seen by an observer's eye when using the first embodiment of the invention at a viewing position (detail view). At the first position according to Fig. 10, the observer's eye sees, for example, predominantly views 5 and 6, while at the second exemplary position according to Fig. 11 it predominantly perceives views 2 and 3. If the observer's different eyes see the mixtures of views shown, a spatial impression is created.

It should also be noted that in this second embodiment, the two filter arrays (Fi, F ₂ ) cannot be made to fully congruent by horizontal and/or vertical linear scaling of their structures. In other words, the structures of the filter arrays do not merge into one another by one- or two-dimensional enlargement or reduction.

The projection screen is translucent and preferably also includes a carrier substrate, e.g. a glass pane. It can also have a light-concentrating effect, ie have a positive "gain".
In this second design, the projection screen is a flat plate.

Here, too, the projectors used are supplied with image data by control electronics, which can also include several separate devices.

Each of the filter arrays (FO and (F ₂ ) is designed as an exposed film. Both filter arrays (Fi, F ₂ ) are each laminated onto a substrate, e.g. onto a glass substrate. This allows a good mechanical hold to be achieved. In the arrangement according to Fig. 1, both filter arrays (Fi, F ₂ ) are always arranged on the side of the glass substrates facing the projectors (4), whereby the glass substrates are not shown in the drawing in Fig. 1.

In a third exemplary embodiment, an arrangement according to Fig.l is also used, but again eight projectors (4) are used instead of the four shown in the drawing. In addition, a third filter (F3) is now present between the filter (Fj) and the projection screen (3). The filter ( _F3 ) is not shown in the drawing in Fig.l.

33 :·

4D Vision GmbH

o.Z.: GM 3DProiektion0702

Jena, 12 July 2002

Each of the eight projectors projects a complete 2D view of the scene/object to be displayed, so that eight views are shown.
The optical axes of the projectors preferably intersect in the center of the projection screen (3), with two adjacent optical axes enclosing an angle of approximately 3.5 degrees. The projectors (4) are aligned accordingly and have a projection distance of, for example, 2900 mm from the center of the projection screen 3. The projectors can advantageously be arranged on a circular path with said center of the surface as the center of the circle.

All projector lenses are preferably located at the same height behind the projection screen, approximately at the height of the center of the projection screen. An appropriately dimensioned mechanical tripod is suitable for ensuring this type of positioning.

Fig. 12 shows a detail of the first projector-side filter array (Fi) of the third embodiment of the invention. The wavelength filter elements (ßi _pq ) in the grid of rows (qi) and columns (pi) are arranged according to the rule already described several times, with the following parameters being selected here: In this embodiment, several of the transparency wavelengths/wavelength ranges λ&igr;^ have the same filter effects: Let λ^ and λ&igr;^.,λ&igr;,βgr; be wavelength ranges that block the entire visible spectrum, λ&igr;,2 be a filter range that is transparent to the visible spectrum, and let ni _m =8 and di _pq =-l=const. A transparent or opaque filter element here is, for example, approximately 0.2847 mm wide and approximately 0.8044 mm high. Other designs are of course conceivable.

Fig. 13 shows a section of the second projector-side filter array (F3) with A=3 of the third embodiment of the invention. The wavelength filter elements (ß3 _Pq ) in the grid of rows (q3) and columns (p3) are arranged according to the rule already described several times, whereby the following parameters were selected here: Let λ3,δ to λ33 be wavelength ranges for the colors red, green and blue in this order, and let n3 _m =3 and

_ P ₃ -Jp ₃ mod 3)

^3W "

-34-

4D-Vision GmbH * Jena, July 12, 2002

o.Z.: GM 3DProjection0702

For example, a filter element here is approximately 0.281 mm wide and approximately 0.796 mm high. Other designs are of course conceivable. In Fig. 13, the colored filter elements, i.e. the wavelength filter elements, are marked with an apostrophe (R', G' and B') to distinguish them from RGB image elements.

Fig. 14 shows the viewer-side filter array (F2) of the third embodiment of the invention, also as a section. Let b2max=4, whereby three transparency wavelengthsZ-wavelength ranges λ2,γ, λ2,2, λ2,3 are specified for the transparency wavelength ranges red, green and blue (in this order) and a further transparency wavelength range λ2,4 with which the visible light can be completely blocked. The coefficient matrix d2 _Pq is generated according to the rule:

Here, n2 _m =8; "mod" denotes the residue class with respect to a divisor. The function &dgr; returns the value "zero" for all arguments not equal to "zero"; for the argument "zero" the function value is 1, because S(O)=I and &dgr;(&khgr;?&udiagr;)=0. The indices (p2,q2) run through all possible values that lie within the filter grid to be generated; for example, for p2 these are values from 1 to 3840 and for q ₂ values from 1 to 768.
Here, for example, a filter element is approximately 0.285 mm wide and 0.804 mm high, although other dimensions are possible.

The filter array (Fi) is arranged at a distance zi =2 mm and the filter array (F3) is arranged at a distance Z3 =1 mm behind the projection screen.

For the array (F2) the distance is Z2=(-)45 mm, whereby this array is located in front of the projection screen in the viewing direction. The minus sign means that the array is located in front of the projection screen in the viewing direction.

If the projectors are aligned as described above, an image structure is created on the projection screen, which is shown in detail in Fig. 15. The grid with columns (i) and rows (j) is only shown for the sake of clarity and is of course not necessarily visible on the projection screen (3). The image created on the projection screen, which is combined from various partial information from the views (Ak), therefore has a grid of image display elements (a,j) in columns (i) and rows (j). The image display elements (cCy) can emit light of very different types.

·

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4D Vision GmbH

GM 3DProjectionQ702

Jena, 12 July 2002

Emit wavelength ranges - depending on what kind of light from the projectors arrives at the corresponding point on the projection screen. If DMD/DLP projectors are used in this example, this time, due to the second projector-side filter (F3), these are not full-color image display elements (ofy), but rather those that generally emit light in the wavelength ranges for red, green or blue. This is indicated in Fig. 15 by the columns labeled R, G and B.

The light propagation directions predetermined by the filter (F ₂ ) ensure that from each viewing position a viewer (5) optically perceives with one eye predominantly partial information of a first selection and with the other eye predominantly partial information of a second selection from the views (Ak), whereby a spatial impression is created for the viewer (5) from a large number of viewing positions.

It should also be noted that in this third embodiment, the three filter arrays (Fi, F ₂ ) cannot be made completely congruent by horizontal and/or vertical linear scaling of their structures. In other words: the structures of the filter arrays do not merge into one another by one- or two-dimensional enlargement or reduction. In relation to the spatial impression, this non-congruence has the effect that from every viewing point, the observer's eye actually always perceives a mixture of partial information from several views.

The projection screen is translucent and preferably also comprises a carrier substrate, eg a glass pane. It can also have a light-concentrating effect, ie have a positive "gain". Excellent sharpness of the image elements on the projection screen is achieved if the projection screen is designed as a very thin pane, preferably with a thickness of less than one millimeter.
In this third design, the projection screen is a flat plate.

Here, too, the projectors used are supplied with image data by control electronics, which can also include several separate devices.

Each of the filter arrays Fi, F ₂ and F3 is designed as an exposed film. They are each laminated onto a substrate, e.g. a glass substrate.

4D Vision GmbH

o.Z.: GM 3DProiektion0702

Jena, 12 July 2002

In a fourth exemplary embodiment, an arrangement according to Fig. 1 is also used, although eight projectors (4) are used instead of the four shown in the drawing. Each of the eight projectors (4) again projects a complete 2D view of the scenery/object to be displayed, so that eight views are shown.

The optical axes of the projectors (4) preferably intersect in the center of the projection screen (3), with two adjacent optical axes enclosing an angle of, for example, approximately 3.5 degrees. The projectors (4) are aligned accordingly and have a projection distance of, for example, 2900 mm from the center of the projection screen (3). The projectors (4) can advantageously be arranged on a circular path with said center of the surface as the circle center.
All projector lenses are located at the same height behind the projection screen (3), approximately at the height of the center of the projection screen (3). To ensure this kind of positioning, an appropriately dimensioned mechanical tripod is suitable.

In Fig. 16, the projector-side filter array (Fi) of the fourth embodiment of the invention is shown as a section. The wavelength filter elements (ßi _pq ) in the grid of rows (qO) and columns (pi) are arranged according to the rule already described several times, whereby the following parameters were selected here: Let λ&igr;,&igr;..λr;&igr;,4 and λ&igr;,6..λr;&igr;,8 be wavelength ranges that block the entire visible spectrum, λ&igr;, ₅ be a filter range that is transparent to the visible spectrum and let bi _ma x=8, ni _m =8 and

_ P ₁ - (integerPart{p _x + &psgr;) mod &dgr;)

⁼ I

For example, a transparent or opaque filter element is approximately 0.2847 mm wide and approximately 0.8044 mm high. Other designs are of course conceivable.

Fig. 17 shows the viewer-side filter array (F ₂ ) of the fourth embodiment of the invention, also as a section. These are &lgr;2,4..&lgr; 2,24 wavelength ranges that block the entire visible spectrum; &lgr;2,&igr;..&lgr; 2,3 are filter ranges that are transparent to the visible spectrum, and b2max=24, n2 _m =24 and

4D-Vision GmbH ·* ·· Jena, July 12, 2002

o.Z.: GM 3DProiektion0702

_ P ₂ -(lntegerPart(p ₂ +2-q ₂ ) mod24)

Here, for example, a transparent or opaque filter element is approximately 0.095 mm wide and approximately 0.804 mm high, although other dimensions are quite realistic.

The filter array (Fi) is arranged at a distance z\ =2 mm behind the projection screen. For the array (F2) the distance is Z2=(-)45 mm, whereby this array is located in front of the projection screen in the viewing direction. The minus sign means that the array is located in front of the projection screen in the viewing direction.

In order to achieve improved image contrast, an anti-reflection coating is preferably applied to the filter array (F2) that is closest to the viewer. This prevents extraneous light reflections to a certain extent, thereby improving the perceptibility of the spatial image.

If the projectors are aligned as described above, an image structure is created on the projection screen, which is shown in detail in Fig. 18. The grid with columns (i) and rows (j) is only shown for the sake of clarity and is of course not necessarily visible on the projection screen (3). The image created on the projection screen, combined from various partial information from the views Ak, therefore has a grid of image display elements (oty) in columns (i) and rows (j). The image display elements (α _�ugr; ) can emit light in very different wavelength ranges - depending on what kind of light arrives from the projectors at the corresponding point on the projection screen. If DMD/DLP projectors are used in this embodiment, these are full-color image display elements (ay).

When correctly aligned, the arrangement according to the invention is particularly efficient in terms of light and space utilization, since each surface element on the projection screen can be exposed to light from at least one of the projectors. This means that no "permanent black spots" are created on the screen, so that each surface element of the projection screen emits some partial information of at least some view.

The light propagation directions specified by the filter (F2) ensure that from any viewing position an observer (5) with one eye predominantly

4D-Vision GmbH · Jena, July 12, 2002

o.Z.: GM 3DProjection0702

Partial information of a first selection and with the other eye predominantly partial information of a second selection from the views (Ak), whereby a spatial impression is created for the viewer (5) from a multitude of viewing positions. Fig. 19 and Fig. 20 each show a possible mixture of views that can be seen by an observer's eye when using the first embodiment of the invention at a viewing position (detail view). At the first position according to Fig. 19, the observer's eye sees predominantly views 1 and 2, for example, while at the second exemplary position according to Fig. 20 it predominantly perceives views 4 and 5. If the observer's different eyes now see the mixtures of views shown, a spatial impression is created.

It should be noted again that in this fourth embodiment, the two filter arrays (Fi, F2) cannot be made completely congruent by horizontal and/or vertical linear scaling of their structures. In other words: the structures of the filter arrays do not merge into one another by one- or two-dimensional enlargement or reduction. In relation to the spatial impression, this non-congruence has the effect that from every viewing point, an observer's eye actually always perceives a mixture of partial information from several views (see also the example mixtures of views in Fig. 19 and Fig. 20). The case where an observer's eye sees partial information from exactly one view from one position in the viewing space is completely excluded.

The projection screen is translucent and preferably also comprises a carrier substrate, eg a glass pane. It can also have a light-concentrating effect, ie have a positive "gain". Excellent sharpness of the image elements on the projection screen is achieved if the projection screen is designed as a very thin pane, preferably with a thickness of less than one millimeter.
In this fourth embodiment, the projection screen is a flat plate.

Here, too, the projectors used are supplied with image data by control electronics, which can also include several separate devices.

Each of the filter arrays (Fj) and (F2) is designed as an exposed film. Both filter arrays (Fi, F2) are laminated onto a substrate, e.g. a glass substrate. This allows a

4D Vision GmbH

o.Z.: GM 3DProjection07Q2

Jena, 12 July 2002

good mechanical hold can be achieved. In the arrangement according to Fig.l, both filter arrays (Fi, F2) are always arranged on the side of the glass substrates facing the projectors 4.

In a fifth exemplary embodiment, an arrangement according to Fig. 1 is also used, but instead of the four projectors (4) shown in the drawing, only one projector is used. The projector is, for example, a DMD/DLP projector and shows red, green and blue images periodically in succession, with the red image corresponding to view Aj (k=1), the green image to view A2 (k=2) and the blue image to view A3 (k=3). Thus, n=3 views are shown.
The optical axis of the projector is preferably aligned with the center of the projection screen (3). The projection distance is, for example, 2000 mm from the center of the projection screen (3).

The projector lens is located approximately at the height of the center of the projection screen or below.

In Fig. 21, the projector-side filter array (Fi) of the fifth embodiment of the invention is shown as a section. The wavelength filter elements (ßi _pq ) in the grid of rows (q0) and columns (pi) are arranged according to the rule already described several times, whereby the following parameters were selected here: Let λ&igr;&igr; be a transparency wavelength range for blue light, λ&igr;,2 a transparency wavelength range for red light, λ&igr;,3 a transparency wavelength range for green light, bi _max =3, ni _m =3 and di _pq =-l=const. A filter element here is, for example, approximately 0.285 mm wide and 0.804 mm high. Other designs are of course conceivable.

Fig. 22 shows the viewer-side filter array (F2) of the fifth embodiment of the invention, also as a section. The corresponding parameters are: &lgr;2,&igr; and &lgr;2,3 are wavelength ranges that block the entire visible spectrum; &lgr;2,2 is a filter range that is transparent to the visible spectrum, and b2max=3, n2 _m =3 and d2 _Pq =-l=const. Here, too, a transparent or opaque filter element is, for example, approximately 0.285 mm wide and 0.804 mm high, although other dimensions are certainly possible.

The filter array (Fi) is arranged at a distance of zi =2 mm behind the projection screen. For the array (F2) the distance is Z2=(-)45 mm, whereby this array is

4D Vision GmbH

o.Z.: GM 3DProjection0702

Jena, 12 July 2002

in front of the projection screen. The minus sign indicates that the array is in front of the projection screen in the viewing direction.

In order to achieve improved image contrast, an anti-reflection coating is preferably applied to the filter array (F2) that is closest to the viewer. This prevents extraneous light reflections to a certain extent, thereby improving the perceptibility of the spatial image.

If the projector is aligned as described above, an image structure is created on the projection screen, which is shown in detail in Fig. 23. The grid with columns (i) and rows (j) is only shown for the sake of clarity and is of course not necessarily visible on the projection screen (3). The image created on the projection screen (3), combined from various partial information from the views (Ak), therefore has a grid of image display elements (ccy) in columns (i) and rows (j). The image display elements (a,j) emit light in very different wavelength ranges; according to the arrangement geometry, the visible partial information from view Ai (k=l) is red, view A2 (k=2) is green, and view A ₃ (k=3) is blue.

The light propagation directions predetermined by the filter (F2) ensure that from each viewing position a viewer (5) optically perceives with one eye predominantly partial information of a first selection and with the other eye predominantly partial information of a second selection from the views (Ak), whereby a spatial impression is created for the viewer (5) from a multitude of viewing positions.

It should be noted again that in this fifth embodiment example, the two filter arrays (Fi, F2) also cannot be brought into complete congruence by horizontal and/or vertical linear scaling of their structures; this is prevented here in particular by the different predetermined transmission wavelength ranges of the two filter arrays (Fi, F2).

The projection screen is translucent and preferably also includes a carrier substrate, e.g. a glass pane. It can also have a light-concentrating effect, i.e. have a positive "gain". Excellent sharpness of the image elements on the

4D Vision GmbH

o.Z.: GM 3DProiektion0702

Jena, 12 July 2002

Projection screen is achieved when the projection screen is designed as a very thin disc, preferably with a thickness of less than one millimeter.

In this fifth embodiment, the projection screen is a flat plate.

The projector used here is also supplied with image data by control electronics. Due to the spectral separation of the views, a PC controlled by appropriate software is recommended.

Each of the filter arrays (Fi) and (F2) is designed as an exposed film. Both filter arrays (Fi, F2) are each laminated onto a substrate, e.g. onto a glass substrate. This allows a good mechanical hold to be achieved. In the arrangement according to Fig.l, both filter arrays (Fi, F2) are always arranged on the side of the glass substrate facing the projectors (4).

For all described embodiment variants of the invention, as already mentioned, in addition to particularly preferred rectangular filter outlines, any filter outlines can also be used for the filter elements. Fig. 24 shows various usable outlines for filter elements in arrangements according to the invention, whereby under certain circumstances at least two different outline shapes can be formed simultaneously on a filter array. The use of such outlines has a positive influence on the moiré behavior of the projection arrangement and also serves to reduce the moiré effects that occur.
It can also be advantageous if concave and convex filter element contours are arranged in such a way that they interlock. The dimensions of the filter elements should be the outermost dimensions in horizontal and vertical extension.

Very special requirements in the image combination structure or in the specification of the light propagation directions can also be met under certain circumstances if individual filter elements already have a color gradient or a gray wedge as a transparency wavelength range or as a neutral filter transmission property.

The invention can be used excellently in the field of entertainment (3D cinema) and also in the field of presentation. Particularly noteworthy is the fact that - depending on the design - several viewers can see a large-format, brilliant 3D image with a great deal of freedom of movement. Components that are easily available or easy to manufacture can be used.

LU" .::!U .:! 14-1": &Iacgr; V i i &Iacgr;

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4D-Vision GmbH ·· ·· ···· ·· · *··" ···· Jena, July 12, 2002 CE: GM 3DProiektion0702

List of reference symbols

Ak Views to be displayed

&eegr; Total number of views Ak

k Number of a specific view Ak (k= 1. .n)

F2,.. F _A Various filter arrays

A index of a specific filter array

&lgr; transparency wavelength

Δλ Transparency wavelength range

i Column index on the projection screen

j Line index on the projection screen

OCiJ Image rendering elements in columns i and rows j

Pa Column index of the filter array Fa

qA row index of the filter array company

pApq Wavelength filter elements in the grid (pA,qA) of the filter array Fa

b integer with values between 1 and bAmax

ÄFrom specified transparency wavelength/transparency wavelength range

n _Am integer value greater than "zero"

dApq selectable mask coefficient matrix

Za Distance from projection screen

&zgr; Distance from projection screen

3 Projection screen

4 projector(s)

5 viewers

·

Claims (43)

1. Autostereoscopic projection arrangement comprising: - at least two projectors, - a projection screen, - at least two filter arrays (F ₁ , F ₂ , . . F _A , . .), wherein at least one filter array (F ₁ ) is arranged between the projection screen and the at least two projectors, ie behind the projection screen in the viewing direction, and at least one filter array (F ₂ ) is arranged in front of the projection screen in the viewing direction, wherein - all filter arrays (F ₁ , F ₂ ,. ., F _A ,. .) have wavelength filter elements arranged in columns and rows which are transparent to light of different wavelengths (λ) or different wavelength ranges (Δλ), - by means of the projectors, partial information from n views (A _k with k = 1. .n; n ≥ 2) of a scene or an object is projected onto the projection screen through at least one filter array (F ₁ ), so that partial information from the views A _k is made optically visible on the projection screen in a combination or mixture determined by the arrangement geometry, and the projection screen is divided into a sufficiently resolving grid of image display elements (α _ij ) in columns (i) and rows (j), which, depending on the characteristics of the filter arrays (F ₁ , F ₂ ,. . F _A ,. .) and the projectors, each emit light of certain wavelengths (λ) or wavelength ranges, and each image display element (α _ij ) displays partial information(s) from at least one of the views A _k , - for the light emitted from the projection screen towards the viewer, directions of propagation are specified by the at least one filter array (F ₂ ) which is arranged in front of the projection screen in the viewing direction, wherein in each case an image display element (α _ij ) corresponds to a plurality of associated wavelength filters of the filter array (F ₂ ) or a wavelength filter of the filter array (F ₂ ) corresponds to a plurality of associated image display elements (α _ij ) in such a way that the connecting line between the center of gravity of the cross-sectional area of a visible section of the image display element (α _ij ) and the center of gravity of the cross-sectional area of a visible section of the wavelength filter corresponds to a direction of propagation, so that from each viewing position an observer optically perceives with one eye predominantly partial information from a first selection and with the other eye predominantly partial information from a second selection from the views (A _k ), whereby a spatial impression is created for the observer from a plurality of viewing positions. 2. Arrangement according to claim 1, characterized in that each of the filter arrays (F ₁ , F ₂ , . . F _A , . .) contains wavelength filter elements (β _Apq ) in a respective separate, filter array-associated grid of rows (q _A ) and columns (p _A ), which are arranged on the filter array according to the following function depending on their transparency wavelength/their transparency wavelength range (λ _b )

b = P _A - d _Apq .q _A - n _Am .IntegerPart[(P _A - d _Apq .q _A - 1)/n _Am ], with
1. (p _A = p) the index of a wavelength filter (ß _Apq ) in a row of the respective array (F _A ), - (q _A = q) the index of a wavelength filter (ß _Apq ) in a column of the respective array (F _A ), - ( _b ) an integer which defines one of the intended transparency wavelength/wavelength ranges (λ b ) for a wavelength filter (ß _Apq ) of the filter array (F _A ) at the position (p _A , q _A ) and which can have values between 1 and b _Amax , - (n _Am ) an integer value greater than zero, preferably corresponding to the total number (n) of views (A _k ) displayed by the projectors, - (d _APq ) a selectable mask coefficient matrix for varying the arrangement of the wavelength filters on the respective array (F _A ) and - IntegerPart of a function to produce the largest integer that does not exceed the argument enclosed in square brackets. 3. Arrangement according to claim 1 or 2, characterized in that at least two of the filter arrays cannot be brought into complete congruence by horizontal and/or vertical linear scaling of their structures. 4. Arrangement according to one of the preceding claims, characterized in that at least some of the filter elements of at least one of the filter arrays (F ₁ , F ₂ , . . F _A , . .) are designed as neutral filters for wavelength-independent attenuation of the light intensity. 5. Arrangement according to one of the preceding claims, characterized in that the filter elements of the filter arrays (F ₁ , F ₂ , . . F _A , . .) have any desired, preferably polygonal, particularly preferably rectangular, outline shapes. 6. Arrangement according to one of the preceding claims, characterized in that the filter arrays (F ₁ , F ₂ ,. . F _A ,. .) are each arranged at a distance (z _A ) in the viewing direction in front of or behind the projection screen and (z _A ) each assumes values in the order of magnitude -60 mm ≤ (z _A ) ≤ 60 mm, whereby a negative value for (z _A ) means the arrangement in the viewing direction in front of the projection screen and a positive value for (z _A ) means the arrangement in the viewing direction behind the projection screen, each at a distance of the absolute value of (z _A ). 7. Arrangement according to one of the preceding claims, characterized in that at least some of the filter elements of at least one of the filter arrays (F ₁ , F ₂ , . . F _A , . .) are designed such that said filter elements only transmit light of selected directions of incidence. 8. Arrangement according to one of the preceding claims, characterized in that at least one filter element of at least one of the filter arrays (F ₁ , F ₂ , . . F _A , . .) is designed as a lens, preferably as a cylindrical lens, or as a prism, wherein the cylindrical lenses or prisms can also be arranged only in columns or rows. 9. Arrangement according to one of the preceding claims, characterized in that the projection screen is translucent. 10. Arrangement according to one of the preceding claims, characterized in that at least one of the at least two projectors projects a combination image composed of partial information from at least two views (A _k ). 11. Arrangement according to claim 10, characterized in that at least two projectors each project a combination image composed of partial information from at least two views (A _K ) and the image combination structure of the views (A _K ) is selected differently for said two projectors. 12. Arrangement according to one of the preceding claims, characterized in that the projected partial information of the views (A _K ) is projected using an image pre-distortion function. 13. Arrangement according to one of the preceding claims, characterized in that the alignment and structure of the filter array(s) between the projectors and the projection screen is selected such that each surface element on the projection screen can be exposed to light from at least one of the projectors. 14. Arrangement according to one of the preceding claims, characterized in that the projection screen is curved, whereby essentially the same angle of incidence is achieved for the light from the various projectors. 15. Arrangement according to one of the preceding claims, characterized in that a separate projection position and projection direction in relation to the projection screen is specified for each projector, wherein the respective projection direction and the respective projection distance preferably differ from projector to projector. 16. Arrangement according to one of the preceding claims, characterized in that the brightness of at least one projector is variably adjustable within predetermined limits. 17. Arrangement according to one of the preceding claims, characterized in that slide projectors, DLP/DMD projectors, CRT projectors or liquid crystal projectors are used as projectors. 18. Arrangement according to one of the preceding claims, characterized in that an anti-reflection coating is applied to the filter array which is closest to the viewer. 19. Arrangement according to one of the preceding claims, characterized in that the filter arrays (F ₁ , F ₂ , . . F _A , . .) are designed as an exposed film, as a printed image or as an optical grating. 20. Arrangement according to one of the preceding claims, characterized in that at least one of the filter arrays (F ₁ , F ₂ , . . F _A , . .) is laminated to a substrate, preferably to a glass substrate. 21. Arrangement according to one of claims 1-19, characterized in that at least one of the filter arrays (F ₁ , F ₂ , . . F _A , . .) is arranged within a sandwich structure consisting of several substrates, wherein the substrates each have certain optical properties - such as predetermined refractive indices. 22. Arrangement according to one of the preceding claims, characterized in that the projection screen is designed as a very thin disk, preferably with a thickness of less than one millimeter, whereby an excellent sharpness of the image elements on the projection screen is achieved. 23. Arrangement according to one of the preceding claims, characterized in that the projection screen has a light-concentrating effect, i.e. has a positive "gain". 24. Arrangement according to one of the preceding claims, characterized in that a reflective surface is located on parts of at least one filter array and this reflective surface is arranged on the side of the filter array(s) facing the projectors and preferably only on the non-transparent filter elements, so that part of the projected light is reflected back into the projectors. 25. Arrangement according to one of the preceding claims, characterized in that at least a part of the filter elements of at least one of the filter arrays (F ₁ , F ₂ , . . F _A , . .) is designed as a polarization filter and that at least one of the projectors emits polarized light. 26. Arrangement according to claim 25, characterized in that the at least one projector emitting polarized light emits the light in temporally alternating polarization, preferably alternately horizontally linearly and vertically linearly polarized. 27. Arrangement according to one of the preceding claims, characterized in that at least some of the filter elements of at least one of the filter arrays (F ₁ , F ₂ , . . F _A , . .) are designed as photochromic or electrochromic optical components. 28. Arrangement according to one of the preceding claims, characterized in that at least one of the projectors is covered with a color filter, whereby the light emitted by said projector can only penetrate wavelength filters of the corresponding transparency wavelength or the corresponding transparency wavelength range. 29. Arrangement according to one of the preceding claims, characterized in that the projectors are arranged in at least two substantially horizontal rows. 30. Arrangement according to one of the preceding claims, characterized in that means for automatically aligning the projectors, for example electromechanical actuators, are also provided. 31. Arrangement according to one of the preceding claims, characterized in that the light path of the light emitted by at least one projector is folded by the use of at least one mirror. 32. Arrangement according to claim 31, characterized in that the folded beam path causes a non-perpendicular light incidence on the projection screen with respect to the main light propagation direction and the projection screen is designed as a holographic disk which transmits in particular non-perpendicularly incident light in a concentrated manner, for example as a "HOPS" disk from Sax3D GmbH/Chemnitz. 33. Autostereoscopic projection arrangement comprising: - at least two projectors, - a projection screen suitable for front projection, - a filter array arranged between the projection screen and the at least two projectors, wherein - the filter array has wavelength filter elements arranged in columns and rows which are transparent to light of different wavelengths (λ) or different wavelength ranges (Δλ) and which absorb at least a portion of the corresponding non-transmitted light - but preferably to a high degree, - by means of the projectors, partial information from n views (A _k with k = 1. .n; n ≥ 2) of a scene or an object is projected through the filter array onto the projection screen, so that partial information from the views (A _k ) is made optically visible on the projection screen in a combination or mixture determined by the arrangement geometry, and the projection screen is divided into a sufficiently resolving grid of image display elements (α _ij ) in columns (i) and rows (j), which, depending on the characteristics of the filter array and the projectors, each emit light of certain wavelengths (X) or wavelength ranges, and each image display element (α _ij ) displays partial information(s) from at least one of the views A _k , - for the light emitted from the projection screen on the projection side towards the viewer, directions of propagation are predetermined by the filter array, wherein in each case an image display element (α _ij ) corresponds to a plurality of associated wavelength filters of the filter array or a wavelength filter of the filter array corresponds to a plurality of associated image display elements (α _ij ) in such a way that the connecting line between the center of gravity of the cross-sectional area of a visible section of the image display element (α _ij ) and the center of gravity of the cross-sectional area of a visible section of the wavelength filter corresponds to a direction of propagation, so that from each viewing position an observer optically perceives with one eye predominantly partial information of a first selection and with the other eye predominantly partial information of a second selection from the views (A _k ), whereby a spatial impression is created for the observer from a plurality of viewing positions. 34. Arrangement according to claim 33, characterized in that the filter array contains wavelength filter elements (β _pq ) in a grid of rows (q) and columns (p) which are arranged on the filter array according to the following function depending on their transparency wavelength/transparency wavelength range (λ _b )
b = p - d _pq - q - n _m .IntegerPart [(p - d _pq .q - 1)/n _m ], with 1. (p) the index of a wavelength filter β _pq in a row of the array, - (q) the index of a wavelength filter β _pq in a column of the array, - (b) an integer which defines one of the intended transparency wavelengths/wavelength ranges (λb ) for a wavelength filter (β _pq ) of the filter array at position (p, _q ) and which can have values between 1 and b _max , - (n _m ) an integer value greater than zero, preferably corresponding to the total number (n) of views (A _k ) displayed by the projectors, - (d _pq ) a selectable mask coefficient matrix for varying the arrangement of the wavelength filters on the array and - IntegerPart of a function to produce the largest integer that does not exceed the argument enclosed in square brackets. 35. Arrangement according to one of claims 33 or 34, characterized in that at least some of the filter elements of the filter array are designed as neutral filters for wavelength-independent attenuation of the light intensity. 36. Arrangement according to one of claims 33-35, characterized in that the filter elements of the filter array have any desired, preferably polygonal, particularly preferably rectangular outline shapes. 37. Arrangement according to one of claims 33-36, characterized in that the filter array is arranged on the projector side at a distance (z) in front of the projection screen, and (z) assumes values in the order of magnitude 0 mm ≤ z ≤ 60 mm. 38. Arrangement according to one of claims 33-37, characterized in that at least some of the filter elements of the filter array are designed such that said filter elements only transmit light of selected directions of incidence. 39. Autostereoscopic projection arrangement comprising: - a projector, - a projection screen suitable for front projection, - a filter array arranged between the projection screen and the projector, whereby - the filter array has wavelength filter elements arranged in columns and rows which are transparent to light of different wavelengths (λ) or different wavelength ranges (Δλ) and which absorb at least a portion of the corresponding non-transmitted light - but preferably to a high degree, - by means of the projector, partial information from (n) views (A _k with k = 1. .n; n ≥ 2) of a scene or an object is projected through the filter array onto the projection screen, so that partial information of the views (A _k ) is made optically visible on the projection screen in a combination or mixture determined by the arrangement geometry, and the projection screen is divided into a sufficiently resolving grid of image display elements (α _ij ) in columns (i) and rows (j), which, depending on the characteristics of the filter array and the projector, each emit light of certain wavelengths (λ) or wavelength ranges, and each image display element (α _ij ) displays partial information(s) of at least one of the views (A _k ), - for the light emitted from the projection screen on the projection side towards the viewer, directions of propagation are predetermined by the filter array, wherein in each case an image display element (α _ij ) corresponds to a plurality of associated wavelength filters of the filter array or a wavelength filter of the filter array corresponds to a plurality of associated image display elements (α _ij ) in such a way that the connecting line between the center of gravity of the cross-sectional area of a visible section of the image display element (α _ij ) and the center of gravity of the cross-sectional area of a visible section of the wavelength filter corresponds to a direction of propagation, so that from each viewing position an observer optically perceives with one eye predominantly partial information of a first selection and with the other eye predominantly partial information of a second selection from the views (A _k ), whereby a spatial impression is created for the observer from a plurality of viewing positions. 40. Autostereoscopic projection arrangement comprising: - a projector, - a translucent projection screen, - at least two filter arrays (F ₁ , F ₂ , . . F _A , . .), wherein at least one filter array (F ₁ ) is arranged between the projection screen and the projector, ie behind the projection screen in the viewing direction, and at least one filter array (F ₂ ) is arranged in front of the projection screen in the viewing direction, wherein - all filter arrays (F ₁ , F ₂ , . ., F _A , . .) have wavelength filter elements arranged in columns and rows which are transparent to light of different wavelengths (X) or different wavelength ranges (Δλ), - by means of the projector, partial information from n views (A _k with k = 1. .n; n ≥ 2) of a scene or an object is projected through at least one filter array (F ₁ ) onto the projection screen, so that partial information of the views (A _k ) is made optically visible on the projection screen in a combination or mixture determined by the arrangement geometry, and the projection screen is divided into a sufficiently resolving grid of image display elements (α _ij ) in columns (i) and rows (j), which, depending on the characteristics of the filter arrays (F ₁ , F ₂ , . . F _A , . .) and the projector, each emit light of certain wavelengths (λ) or wavelength ranges, and each image display element (α _ij ) displays partial information(s) of at least one of the views (A _k ), - for the light emitted from the projection screen towards the viewer, directions of propagation are specified by the at least one filter array (F ₂ ) which is arranged in front of the projection screen in the viewing direction, wherein in each case an image display element (α _ij ) corresponds to a plurality of associated wavelength filters of the filter array (F ₂ ) or a wavelength filter of the filter array (F ₂ ) corresponds to a plurality of associated image display elements (α _ij ) in such a way that the connecting line between the center of gravity of the cross-sectional area of a visible section of the image display element (α _ij ) and the center of gravity of the cross-sectional area of a visible section of the wavelength filter corresponds to a direction of propagation, so that from each viewing position an observer optically perceives with one eye predominantly partial information from a first selection and with the other eye predominantly partial information from a second selection from the views (A _k ), whereby a spatial impression is created for the observer from a plurality of viewing positions. 41. Arrangement according to claim 39 or 40, characterized in that the projector emits light of different wavelengths or wavelength ranges in temporal succession, and that the partial information of each of the n views is emitted in pairs of different wavelengths or wavelength ranges. 42. Arrangement according to claim 41, characterized in that partial information from n = 3 views (A _K with k = 1. .n) is displayed, that the projector is a DMD/DLP projector and that view A ₁ (k = 1) is displayed exclusively in red, view A ₂ (k = 2) is displayed exclusively in green and view A ₃ (k = 3) is displayed exclusively in blue. 43. Autostereoscopic projection arrangement comprising: - a translucent projection screen, - a projector located behind the projection screen in the viewing direction, - at least one filter array which is arranged in front of the projection screen in the viewing direction, wherein - the filter array has wavelength filter elements arranged in columns and rows which are transparent to light of different wavelengths (λ) or different wavelength ranges (Δλ), - by means of the projector, partial information from (n) views (A _k with k = 1. .n; n ≥ 2) of a scene or an object is projected directly onto the projection screen in a defined combination of the partial information, so that partial information of the views (A _k ) is made optically visible on the projection screen, and the projection screen is divided into a sufficiently resolving grid of image display elements (α _ij ) in columns (i) and rows (j), which, depending on the design of the projector, each emit light of certain wavelengths (λ) or wavelength ranges, and each image display element (α _ij ) displays partial information(s) of at least one of the views (A _k ), - for the light emitted from the projection screen towards the viewer, directions of propagation are predetermined by the at least one filter array, wherein in each case an image display element (α _ij ) corresponds to a plurality of associated wavelength filters of the filter array or a wavelength filter of the filter array corresponds to a plurality of associated image display elements (α _ij ) in such a way that in each case the connecting line between the center of gravity of the cross-sectional area of a visible section of the image display element (α _ij ) and the center of gravity of the cross-sectional area of a visible section of the wavelength filter corresponds to a direction of propagation, so that from each viewing position an observer optically perceives with one eye predominantly partial information of a first selection and with the other eye predominantly partial information of a second selection from the views (A _k ), whereby a spatial impression is created for the observer from a plurality of viewing positions.