JP4767696B2 - Projection-type image display device - Google Patents

Description

  The present invention relates to a projection-type image display apparatus that displays an image on a screen by enlarging and projecting a light image emitted from a light valve toward the screen.

  Conventional projection-type image display devices achieve a thin profile that reduces the depth dimension in the direction perpendicular to the screen by adopting a central projection-type configuration in which the principal ray at the center of the screen enters the screen almost perpendicularly. Yes. For this reason, a rear mirror having no power is provided behind the screen, and the projection light is reflected by the rear mirror and projected onto the screen. In the case of adopting such a configuration, in order to realize further thinning, a method of widening the optical system and a method of bringing the rear mirror close to parallel to the screen can be considered. Since the projection optical system and the projection light interfere with each other, further reduction in thickness cannot be realized.

  As an improvement measure, a configuration has been proposed in which the light valve is arranged offset from the optical axis, and the light valve image is enlarged and projected from an oblique direction with respect to the screen to reduce the thickness (for example, Patent Documents 1 to 3). 3). In such a configuration, a projection optical system having an extremely large projection angle of view is required as compared with the central projection type, and it is advantageous to use a reflection mirror that does not cause chromatic aberration in order to reduce chromatic aberration accompanying widening of the angle. For example, as shown in Patent Document 1, a lens composed of only a plurality of reflecting mirrors has been proposed. In addition, as disclosed in Patent Document 2 or Patent Document 3, a projection optical system that includes a refractive lens group and a reflecting mirror having power has been proposed.

JP 2004-157560 A (FIG. 1) Japanese Patent Laying-Open No. 2002-207168 (FIG. 39) International Publication No. 01/06295 (FIG. 20)

  However, in the case of the oblique projection configuration, in order to avoid interference between the illumination light incident on the light valve and the projection light reflected by the light valve and traveling toward the projection optical system, the light valve is separated from the optical axis of the refractive lens group. It is necessary to arrange them offset by a certain amount or more. In this case, as the offset amount of the light valve is increased, the offset amount between the projected image and the optical axis of the refractive lens group is increased in accordance with the projection magnification represented by the ratio between the projected image size and the light valve size. For this reason, there is a problem in that the height of the lower part of the screen where no image is displayed from the lower end of the apparatus to the lower end of the screen increases, and the apparatus becomes larger than necessary.

  Accordingly, the present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide a projection image display apparatus in which the apparatus is thin in the depth direction and the height of the portion under the screen is small. And

The projection-type image display device of the present invention includes an illumination optical system including a light source, a reflective light valve that emits light from the illumination optical system as a light image, and the light image emitted from the light valve. A projection optical system for magnifying and projecting, and a screen on which a light image magnified by the projection optical system is projected, the projection optical system including a refractive lens group for magnifying a light image from the light valve, and a free lens has a light reflecting surface of the curved shape, and a power mirror having power to expand reflect light image from the refracting lens group at the light reflection surface of the free-form surface, wherein the light valve, the center of the light valve The position is offset in a predetermined direction from the optical axis of the refractive lens group, the diagonal dimension of the light valve is Dl, the side dimension of the light valve in the offset direction is Hl, Di is the diagonal dimension of the projected image on the screen, Di is the distance from the center of the light valve to the optical axis of the refractive lens group, and the optical axis of the refractive lens group is from the center of the projected image on the screen. The projection optical system has the following conditional expression 0.8 ≦ Li / {(Di / Dl) · Ll} <1.0
Li / {Hl · (Di / Dl)}> 0.5
Ll / Hl ≧ 0.54
And the optical image magnified and reflected by the power mirror advances toward the back of the screen in a direction having an inclination with respect to the normal of the screen, and is projected onto the back of the screen. The refractive lens group and the power mirror are arranged .

  According to the projection type image display apparatus of the present invention, the depth of the apparatus can be reduced and the partial height under the screen of the apparatus can be reduced.

Embodiment 1 FIG.
Hereinafter, a projection type image display apparatus 100 according to Embodiment 1 of the present invention will be described with reference to FIGS.

  FIG. 1 is a side view showing an internal configuration and an optical path of the projection type image display apparatus 100 according to the first embodiment. As shown in FIG. 1, a projection image display apparatus 100 includes a light source 1 and an optical system (for example, an illumination lens system, a spherical mirror, an aspherical mirror, a flat surface) that collects illumination light emitted from the light source 1, and the like. And a light valve 3 that displays an image based on the input video signal and receives an illumination light that has passed through the optical system 2 to emit a light image (projection light). A refraction lens group 4 for enlarging the light image emitted from the light valve 3, a power mirror 5 having power for enlarging and projecting the light image magnified by the refraction lens group 4, and the light reflected by the power mirror 5 And a transmissive screen 6 on which an image is projected and displayed. Here, the light source 1 and the optical system 2 constitute an illumination optical system. FIG. 1 shows a case where the screen 6 faces in the horizontal direction (left direction in FIG. 1), and the light source 1, the optical system 2, the light valve 3, the projection lens group 4, and the power lens 5 are arranged below the screen 6. Indicates. However, the light source 1, the optical system 2, the light valve 3, the projection lens group 4, and the power lens 5 are arranged on either the upper side of the screen 6, the left side toward the screen 6, or the right side toward the screen 6. Is also possible.

  The refractive lens group 4 and the power mirror 5 constitute a projection optical system. The light source 1 includes a lamp and a concave mirror that reflects light from the lamp, and a semiconductor light emitting element.

  The light valve 3 is an optical element that emits an optical image by modulating the intensity of light based on an input video signal, and is, for example, a digital micromirror device (DMD: registered trademark of Texas Instruments Incorporated (TI)). . The DMD has a plurality of micromirrors that can individually change the angle, and changes the angle of each micromirror based on the input video signal. The DMD reflects light that has passed through the optical system 2 by each micromirror, and emits spatially intensity-modulated projection light as an optical image. The light valve 3 may be another light spatial modulation element such as a liquid crystal display element. However, in the following description, the case where the light valve 3 is a DMD will be described.

  In FIG. 1, a dotted line 10 extending in the horizontal direction indicates the optical axis of the refractive lens group 4. In FIG. 1, a solid line 21 is emitted from the upper end of the light valve 3, shows a principal ray that passes through the refractive lens group 4 and travels toward the power mirror 5, and a solid line 22 is emitted from the center of the light valve 3, A principal ray that passes through the refractive lens group 4 and travels toward the power mirror 5 is shown. A solid line 23 emerges from the lower end of the light valve 3 and passes through the refractive lens group 4 and travels toward the power mirror 5. In FIG. 1, a solid line 31 indicates a chief ray that is emitted from the upper end of the light valve 3, passes through the refractive lens group 4, enters the power mirror 5, and is reflected by the power mirror 5. Displays the lower end of the projected image on the screen 6. In FIG. 1, a solid line 32 is a principal ray that is emitted from the center of the light valve 3, passes through the refractive lens group 4, enters the power mirror 5, and is reflected by the power mirror 5. Displays the center of the projected image on the screen 6. Further, in FIG. 1, a solid line 33 is a principal ray that is emitted from the upper end of the light valve 3, passes through the refractive lens group 4, enters the power mirror 5, and is reflected by the power mirror 5. Displays the upper end of the projected image on the screen 6.

  Further, in the projection type image display apparatus 100 according to the first embodiment, the light valve 3 is installed with the projection type image display apparatus 100 whose center is directed toward the screen 6 in the horizontal direction (lateral direction in FIG. 1). In this case, the refractive lens group 4 is disposed so as to be offset vertically downward (downward in FIG. 1) from the optical axis 10 of the refractive lens group 4. Such a positional relationship is shown in FIG.

  FIG. 2 is a cross-sectional view showing the configuration of the light valve 3 and the refractive lens group 4 of the projection type image display apparatus 100. As shown in FIG. 2, the projection image display apparatus 100 includes a light valve 3 (OBJ in FIG. 2), a plate-like optical system having surfaces S <b> 1 and S <b> 2, and a refractive lens group 4. . The refractive lens group 4 includes ten lenses (indicated by the surfaces S3, S4, and S6 to S21 from the light valve 2 side) and an aperture stop STO (S5).

  Table 1 shows optical data of the optical system of the projection type image display apparatus 100. Tables 2 to 4 show optical data of the lens surfaces S3, S20, and S21 of the refractive lens group 4 of the projection type image display apparatus 100. Table 5 shows optical data of the surface (mirror surface) S22 of the power mirror 5 of the projection type image display apparatus 100.

  In Table 1, Surf indicates each surface, and each surface is distinguished by a symbol or a number. In the Surf column, OBJ indicates the light valve 3, IMA indicates the screen 6, S22 indicates the mirror surface of the power mirror 5, and S1 to S21 are sequentially attached to the surface of each lens from the light valve 6 side. Corresponds to the face number. In Table 1, Radius represents the radius of curvature (mm) of each component, Thickness represents the surface separation (mm), nd represents the refractive index at the d-line (wavelength 587.6 nm), and vd represents the Abbe number. Show. In addition, STO (S5 in the case of expressing with a surface number) indicates an aperture. Further, the mirror surface of the power mirror 5 is expressed as Mirror. Note that a minus (−) sign added to the numerical value of the surface interval means that the surface is a reflecting surface.

In Table 1, the symbol “*” attached to the surface numbers S3 and S20 indicates that the lens surfaces S3 and S20 are aspherical surfaces, respectively. The aspheric shapes of these lens surfaces S3 and S20 are defined by the following equation (1). In the equation (1), Z1 (r) represents a sag amount at a position away from the optical axis 10 of the projection lens group 4 by the radius r. C represents the curvature at the apex of the lens surface, k represents the conic coefficient, and A _i represents the i-th order (i = 1,...) Aspheric coefficient.
Z1 (r)
= C · r ² / [1+ {1- (1 + k) c ² · r ² } ^1/2 ] + ΣA _i · r ⁱ (1)

In Table 1, the symbol “**” attached to the surface numbers S21 and S22 indicates that the lens surface S21 and the power mirror surface S22 are free-form surfaces. The free curved surface shapes of the lens surface S21 and the power mirror surface S22 are defined by the following equation (2). In Expression (2), Z2 (x, y) is a sag at a position away from the optical axis of the projection lens group 4 or the refraction lens group 4 by x in the horizontal direction and y in the vertical direction (positive in the vertical direction). Indicates the amount. Also,
r = (x ² + y ² ) ^1/2
Where c is the curvature at a point on the lens surface or power mirror surface, k is the conic coefficient, B _i is the i-th order (i = 1,...) Aspheric coefficient, and C _jk is x ^j. It is a free-form surface coefficient of y ^k (j = 1,..., k = 1,...).
Z2 (r)
= C · r ² / [1+ {1− (1 + k) c ² · r ² } ^1/2 ] + ΣB _i · r ⁱ
+ ΣC _jk · x ^j · y ^k (2)

Tables 2 and 3 show the conic coefficient k and the aspheric coefficient A _i for each of the lens surfaces S3 and S20 which are aspherical surfaces. Tables 4 and 5 show the conic coefficient k, the aspheric coefficient B _i, and the free-form surface coefficient C _jk for each of the lens surface S21 and the power mirror surface S22 that are free-form surfaces.

In the projection image display apparatus 100 according to Embodiment 1, the optical axis of the power mirror 5 is decentered by an offset amount of 3.10 mm vertically upward from the optical axis 10 of the refractive lens group 4. Here, “the optical axis of the power mirror 5” means the third term ΣC _jk · x ^j · y ^k from the right side of the equation (2).
, I.e., the following rotationally symmetric shape Z3 (r) = c · r ² / [1+ {1− (1 + k) c ² · r ² } ^1/2 ] + ΣB _i · r ⁱ
Is the optical axis.

  FIG. 3 is a diagram for explaining the operation of the DMD in the comparative example in which the offset amount of the DMD center position with respect to the optical axis of the refractive lens group is zero. In FIG. 3, reference numeral 40 denotes a DMD mirror surface (reference plane), reference numeral 41 denotes an OFF-state micromirror, and reference numeral 42 denotes an ON-state micromirror. In FIG. 3, the broken line 50 indicates the optical axis of the illumination optical system (configurations 1 and 2 in FIG. 1), the solid line 51 indicates the illumination light, and the broken line 60 indicates the minute mirror 42 in which the optical axis 50 of the illumination light is ON. The solid line 61 indicates the projection light that is reflected by the minute mirror 42 in the illumination state and directed toward the entrance pupil of the projection lens group 4 along the optical axis of the reflected projection light. In FIG. 3, the broken line 70 indicates the optical axis of the OFF light that is reflected by the micromirror 41 in the OFF state and does not contribute to the projection, and the solid line 71 indicates the OFF light. In FIG. 3, the angle α indicates the tilt angle of the DMD (that is, the angle of the minute mirror with respect to the reference surface 40). Further, the angle β indicates the maximum angle formed by the illumination light 51 with the optical axis of the illumination optical system, and the maximum angle formed by the projection light 61 with the optical axis of the projection light. The angle γ indicates an angle formed by the optical axis 50 of the illumination light and the optical axis 60 of the projection light. The optical axis 60 of the projection light is the same as the optical axis 10 of the projection lens group 4 in FIG. In the DMD, the minute mirror 42 in the ON state reflects the illumination light 51 in the direction of the entrance pupil of the projection optical system, and the reflected projection light 61 is incident on the refractive lens group 4 constituting the projection optical system, Refraction and transmission are repeated and reflected by the power mirror 5 in the direction of the screen 6, and an image is displayed on the screen 6. The OFF light 71 reflected by the micro mirror 41 in the OFF state does not enter the projection optical system and does not contribute to image formation.

In general, the F number Fno is used as an index indicating the brightness of the projection optical system. The F number Fno is expressed by the following equation (3) using the angle β of the projection light 61.
Fno = 1 / (2 · sin β) (3)
In order to obtain a high-brightness projection type image display apparatus, it is necessary to reduce the F number of the projection optical system, that is, to increase the angle β of the projection light 61. However, when the DMD offset amount is 0, the angle β of the projection light 61 cannot be larger than the tilt angle α of the DMD in order to avoid the overlap of the illumination light 51 and the projection light 61. The tilt angle α of the current DMD is 12 °, and when the tilt angle α is equal to the angle β of the projection light, the F number of the projection optical system is about 2.4.

  FIG. 4 is a diagram showing the configuration of a comparative example using a total reflection prism and the optical paths of illumination light and projection light. Normally, when the DMD offset amount is 0, a method of separating illumination light and projection light using a total reflection prism is employed. In the total reflection prism 80 shown in FIG. 4, a first prism 81 and a second prism 82 are arranged with the inclined surface of the first prism 81 and the inclined surface of the second prism 82 facing each other. Yes. The illumination light 90 is incident on the first prism 81 that constitutes the total reflection prism 80. The illumination light 90 incident on the first prism 81 is totally reflected by the inclined surface 83 because the angle of the inclined surface 83 is set so that the angle formed by the illumination light 90 and the inclined surface 83 is larger than the critical angle. Under the action, the light enters the DMD 3 and is reflected by changing the traveling direction according to the tilt angle of the DMD, and then enters the first prism 81 again. At this time, since the angle formed by the projection light 91 and the inclined surface 83 is equal to or less than the critical angle, the projection light 91 is transmitted through the inclined surface 83 and the projection light 91 is transmitted through the prism 82 to constitute the projection optical system. Head toward the entrance pupil of the projection lens. Usually, the entrance pupil of the projection lens is set to infinity. However, when a total reflection prism is used, the contrast of the projected image tends to deteriorate due to stray light caused by scattering of OFF light in the prism. In addition, the total reflection prism is expensive and increases the cost of the apparatus.

  FIG. 5 is a diagram for explaining the operation of the DMD in Embodiment 1 in which the offset amount of the DMD center position with respect to the optical axis 10 of the refractive lens group 4 is large. In FIG. 5 showing the first embodiment, the same reference numerals are assigned to the same or corresponding components as those shown in FIG. 4 showing the comparative example. When the center position of the DMD is offset downward in FIG. 1 with respect to the optical axis 10 of the refractive lens group 4, the optical axis 60 of the projection light reflected by the DMD is relative to the normal direction of the reference surface 40 of the DMD. Thus, an angle corresponding to the offset amount and the projection optical system entrance pupil position is obtained. The angle formed by the optical axis 50 of the illumination light incident on the DMD and the normal direction of the DMD reference plane 40 is larger than when the DMD offset amount shown in FIG. For this reason, the angle formed by the optical axis of the illumination light 51 and the optical axis of the projection light 61 becomes large, and the illumination light 51 and the projection light 61 can be largely separated. Furthermore, the separation angle between the illumination light 51 and the projection light 61 and the OFF light 71 is also increased. Therefore, in the projection type image display apparatus 100 according to Embodiment 1, it is not necessary to use a total reflection prism as shown in FIG. 4 for separating the illumination light 51 and the projection light 61.

  FIG. 6 is a diagram showing optical paths of illumination light and projection light in the case of Embodiment 1 in which a total reflection prism is not used. In the case of Embodiment 1 in which the DMD is greatly offset, it is possible to separate the illumination light and the projection light without using a total reflection prism. In FIG. 6, the same reference numerals are assigned to the same or corresponding components as those shown in FIG. 4. In FIG. 6, reference numeral 92 denotes an entrance pupil of the projection optical system. In such a configuration, the projection light 90 and the illumination light 91 can be easily separated, and the entrance pupil 92 of the projection optical system can be set relatively close to the DMD. Since the entrance pupil diameter is reduced, the projection optical system can be downsized, a lens can be made at a lower cost, and the incidence of unnecessary light that does not contribute to the image can be reduced and high-contrast projection can be achieved. An image can be obtained. Therefore, by offsetting the light valve, it is possible to reduce the thickness of the projection-type image display device, and it is also possible to reduce the cost and increase the contrast.

  However, when the offset amount of the light valve 3 increases, the offset amount of the projected image on the screen 6 also increases. As a result, the height from the lower end of the projection type image display device to the lower end of the projected image on the screen 3, that is, , The area under the screen gets bigger. This will be described below.

Usually, the magnification of the projection optical system is represented by the ratio between the size of the object and the size of the image. Correspondingly, in image projection, the projection magnification M is generally expressed by the following equation (4) using the diagonal dimension Di of the projected image and the diagonal dimension Dl of the light valve 3.
M = Di / Dl (4)
The diagonal dimension Dl of the light valve is usually about 1 inch to 0.5 inch, the projected image diagonal dimension Di is usually about 40 inches to 80 inches, and the projection magnification M is generally about 50 to 100 times. . In the projection type image display apparatus 100, the diagonal dimension Dl of the light valve is 0.79 inches, the diagonal dimension Di of the projected image is 66.34 inches, and the projection magnification M is about 84 times.

In general, in a projection optical system in which distortion is sufficiently corrected, an object placed on the object plane and having a height y from the optical axis 10 of the refractive lens group 4 is reflected on the image plane. The image is formed with a height M · y from the optical axis. Therefore, when the light valve offset amount Ll is increased, the projection image offset amount Li increases in accordance with the projection magnification M, and the relationship between them is expressed by the following equation (5).
Li = M · Ll (5)

  From the above, in order to separate the illumination light and the projection light, it is usually necessary to make the offset amount of the light valve a certain value, at least larger than 0.5 times the short side of the DMD. The offset amount of the projected image is also increased, and as a result, the height from the lower end of the apparatus to the lower end of the projected image is increased. This area is an unnecessary area that does not perform an effective function as a projection type image display apparatus, and it is desirable to make this height as small as possible from the viewpoint of miniaturization of the apparatus.

  Next, the operation of the projection optical system of the projection type image display apparatus 100 will be described. FIG. 7 is a diagram schematically showing the configuration of the projection type image display apparatus 100 shown in FIG. In FIG. 7, L1 indicates the distance between the center of the light valve 3 and the optical axis 10 of the refractive lens group 4, Li indicates the distance between the screen center of the projected image and the optical axis 10 of the refractive lens group 4, and P indicates The distance between the lower end of the projected image and the optical axis 10 of the refractive lens group 4 is shown. Reference numerals 106, 131, 132, and 133 indicate light beams traveling from the power mirror 5 to the screen 6 corresponding to the conventional projection optical system under the same conditions, and reference numerals 6 and 31 in the first embodiment. , 32, and 33, respectively. In FIG. 7, the same or corresponding components as those shown in FIG.

  As described above, the projection light emitted obliquely upward from the DMD 3 offset from the optical axis 10 of the refractive lens group 4 is refracted and transmitted by the refractive lens group 4, and then reflected and enlarged by the power mirror 5. The light enters the screen 6 and an image is projected.

  In general, it is effective to correct distortion of the projection optical system by disposing an element at a position where the height of each principal ray from the optical axis 10 of the refractive lens group becomes high. In the conventional projection optical system, the shape of the power mirror 5 can be corrected to be a rotationally symmetric aspherical shape with the optical axis 10 of the refractive lens group as the center, and the center of the projected image and the refractive lens group can be corrected. The distance from the optical axis 10 is expressed by equation (5).

  On the other hand, in the projection type image display apparatus 100 according to the first embodiment, a function of adding a degree of freedom to the shape of the power mirror 5 as a free-form surface, and controlling the screen position in the vertical direction in addition to the distortion correction capability. Therefore, it is possible to control the screen arrival position of each principal ray exiting the DMD 3 to be closer to the optical axis 10 of the refractive lens group 4 than the arrival position determined by the normal projection magnification. The distance P from the lower end to the optical axis 10 of the refractive lens group 4 can be reduced.

  The refractive lens group 4 has a lens surface closest to the power mirror 5 having a free-form surface, and corrects various aberrations generated by the power mirror 5 giving priority to distortion correction and screen position control. The lens configuration of the refractive lens group 4 is 10 elements in 8 groups, and a configuration equivalent to that of a conventional projection image display apparatus is possible.

The projection type image display apparatus 100 according to Embodiment 1 satisfies the following conditional expressions (6) to (8).
0.8 ≦ Li / {(Di / Dl) · Ll} <1.0 (6)
Li / {Hl · (Di / Dl)}> 0.5 (7)
Ll / Hl ≧ 0.54 (8)

  Conditional expression (6) is calculated based on the distance Ll between the center of the DMD and the optical axis 10 of the refractive lens group 4 and the projection magnification M (= Di / Dl), and is projected by the conventional projection optical system. Li, which is the ratio of the distance Li between the center of the projected image and the optical axis 10 of the refractive lens group 4 projected by the projection type image display device to the distance (M · Ll) between the image center and the optical axis of the refractive lens group. / {(Di / Dl) · Ll} is an appropriate range.

  When Li / {(Di / Dl) · Ll} in conditional expression (6) falls below the lower limit of 0.8, the center position of the screen is calculated based on the projection magnification M and projected by the conventional projection optical system. Therefore, it is difficult to correct the various aberrations generated by the refractive lens group 4 by controlling the screen position by the power mirror 5. become. In this case, interference between the principal ray 23 emitted from the refractive lens group 4 and the screen 6 occurs.

  Further, when Li / {(Di / Dl) · Ll} in the conditional expression (6) exceeds the upper limit value 1.0, the center position of the projected image is more than the optical axis 10 of the refractive lens group 4 than the conventional projection optical system. This means that the device becomes larger.

  Conditional expression (7) defines the positional relationship of the screen position from the optical axis 10, and the dimension {Hl · () in the vertical direction of the screen with respect to the distance Li from the optical axis 10 of the refractive lens group 4 to the center of the screen. Di / Dl)} ratio is greater than 0.5, which means that the entire screen needs to be positioned vertically above the projection optical system.

  If Li / {Hl · (Di / Dl)} in conditional expression (7) is lower than 0.5, the interference between the screen 6 and the projection optical path or projection optical system will occur.

  Conditional expression (8) defines the offset amount Ll of the light valve 3, and means that the ratio of the short side Hl of the light valve to the offset amount Ll is 0.54 or more.

  If Ll / Hl in the conditional expression (8) becomes smaller than the lower limit value 0.54, the offset amount Ll becomes too small and the screen position becomes too close to the optical axis 10 of the refractive lens group 4, so that the screen 6 and the projection optical path Or interference with the projection optical system occurs. In this case, it becomes difficult to separate the illumination light and the projection light.

  In the projection type image display apparatus 100 according to Embodiment 1, the F number of the projection optical system is 3.5, and the distance Ll between the DMD center and the optical axis 10 of the refractive lens group 4 is 7.2 mm. Yes, the projection magnification M = Di / Dl is 83.87 times, and the distance Li between the center of the projected image and the optical axis 10 of the refractive lens group 4 is 550 mm. Further, Li / {(Di / Dl) · Ll} in conditional expression (6) is 0.91, Li / {Hl · (Di / Dl)} in conditional expression (7) is 0.67, Ll / Hl in conditional expression (8) is 0.73. Further, the TV distortion is 0.12% or less, which is sufficiently smaller than about 1% which is a guideline of the upper limit allowable value.

  8 and 9 are aberration diagrams of the projection-type image display apparatus 100 according to the first embodiment. The maximum value on the vertical axis of this aberration diagram is ± 5 mm. In the aberration diagrams of the present application, the horizontal axis (PY, PX) represents pupil coordinates, and the vertical axis (EX, EY) represents aberration. The PY-EY diagram represents the relationship between the pupil coordinates and the aberrations in the tangential direction, and the PX-EX diagram represents the sagittal direction. The aberration diagrams are plotted for light of three wavelengths (solid line is wavelength 460 nm, fine broken line is wavelength 546 nm, coarse broken line is wavelength 650 nm).

  As described above, according to the projection-type image display apparatus 100 according to the first embodiment, the oblique projection that irradiates the projection light traveling in the direction having an inclination with respect to the normal line of the screen 6 is employed. Nevertheless, it is possible to reduce the depth of the device and reduce the height of the portion under the screen. In addition, according to the projection type image display apparatus 100 according to the first embodiment, since a free curved surface shape is adopted for the lens surface and the power mirror 5 surface in addition to the aspherical lens, it is generated by the power mirror 5. Can be corrected satisfactorily.

Embodiment 2. FIG.
Hereinafter, a projection type image display apparatus 200 according to Embodiment 2 of the present invention will be described with reference to FIGS.

  FIG. 10 is a side view showing an internal configuration and an optical path of the projection type image display apparatus 200 according to the second embodiment. In FIG. 10, the same reference numerals are given to the same or corresponding components as those shown in FIG. FIG. 11 is a cross-sectional view showing the configuration of the light valve 3 and the refractive lens group 4 of the projection type image display apparatus 200. In FIG. 11, the same or corresponding elements as those shown in FIG.

  Table 6 shows optical data of the optical system of the projection type image display apparatus 200. Tables 7 to 9 show optical data of the lens surfaces S3, S20, and S21 of the refractive lens group 4 of the projection type image display apparatus 200. Table 10 shows optical data of the surface (mirror surface) S22 of the power mirror 5 of the projection type image display apparatus 200. The optical data description method in Tables 6 to 10 is the same as the optical data description method in Tables 1 to 5 described in the first embodiment.

  In the projection image display apparatus 200 according to Embodiment 2, the optical axis of the power mirror 5 is decentered by an offset amount of 3.10 mm vertically upward from the optical axis 10 of the refractive lens group 4. Here, the “optical axis of the power mirror 5” is the optical axis of the above formula Z3 (r) excluding the third term from the right side of the formula (2).

  The projection type image display apparatus 200 according to the second embodiment is the same as the projection type image display apparatus 100 according to the first embodiment, with the conditions such as the DMD size and the projection image size, the number of components of the refractive lens group 4 being the same. Further, the screen position control of the power mirror 5 is further enhanced, and the projected image is shifted so as to approach the optical axis 10 of the refractive lens group 4. While keeping the size of the power mirror 5 the same, the projected image is as close as possible to the optical axis 10 of the refracting lens group 4 to the extent that there is no interference between the projected image and the principal ray 23 emitted from the refracting lens group 4.

  In the projection type image display apparatus 200 according to Embodiment 2, the F number of the projection optical system is 3.5, and the distance Ll between the DMD center and the optical axis 10 of the refractive lens group 4 is 7.2 mm. Yes, the projection magnification M = Di / Dl is 83.87 times, and the distance Li between the center of the projected image and the optical axis 10 of the refractive lens group 4 is 520 mm. In addition, Li / {(Di / Dl) · Ll} in the conditional expression (6) is 0.86, and Li / {Hl · (Di / Dl)} in the conditional expression (7) is 0.63. Yes, Ll / Hl in conditional expression (8) is 0.73. Further, the TV distortion is 0.13% or less, which is sufficiently smaller than about 1% which is a guideline of the upper limit allowable value. 12 and 13 are aberration diagrams of the projection type image display apparatus 200. FIG. The maximum value on the vertical axis of this aberration diagram is ± 5 mm.

  As described above, according to the projection type image display apparatus 200 according to the second embodiment, the oblique projection that irradiates the projection light traveling in the direction having the inclination with respect to the normal line of the screen 6 is employed. Nevertheless, it is possible to reduce the depth of the device and reduce the height of the portion under the screen.

  In the second embodiment, points other than those described above are the same as those in the first embodiment.

Embodiment 3 FIG.
A projection type image display apparatus 300 according to Embodiment 3 of the present invention will be described below with reference to FIGS.

  FIG. 14 is a side view showing an internal configuration and an optical path of the projection type image display apparatus 300 according to Embodiment 3. In FIG. 14, the same reference numerals are given to the same or corresponding components as those shown in FIG. FIG. 15 is a cross-sectional view showing the configuration of the light valve 3 and the refractive lens group 4 of the projection type image display apparatus 300. In FIG. 15, the same or corresponding components as those shown in FIG.

  Table 11 shows optical data of the optical system of the projection type image display apparatus 300. Tables 12 to 14 show optical data of the lens surfaces S3, S20, and S21 of the refractive lens group 4 of the projection type image display apparatus 300. Table 15 shows optical data of the surface (mirror surface) S22 of the power mirror 5 of the projection type image display apparatus 300. The optical data description method in Tables 11 to 15 is the same as the optical data description method in Tables 1 to 5 described in the first embodiment.

  In the projection type image display apparatus 300 according to Embodiment 3, the optical axis of the power mirror 5 is decentered by an offset amount of 4.23 mm vertically upward from the optical axis 10 of the refractive lens group 4. Here, the “optical axis of the power mirror 5” is the optical axis of the above formula Z3 (r) excluding the third term from the right side of the formula (2).

  The projection type image display apparatus 300 according to the third embodiment is the same as the projection type image display apparatus 200 according to the second embodiment, with the conditions such as the DMD dimensions and the projection image dimensions, and the number of components of the refractive lens group 4 being the same. The F-number of the projection optical system is increased, the screen position control of the power mirror 5 is further enhanced, and the projected image is shifted so as to approach the optical axis 10 of the refractive lens group 4.

  Generally, an ultra-high pressure mercury lamp is often used as the light source 1 for an image projection apparatus. The ultra-high pressure mercury lamp has good luminous efficiency, and if a lamp with a short arc gap is used, the light utilization efficiency can be made relatively good. However, the lifetime of the current ultra-high pressure mercury lamp is not sufficiently long. If the output of the lamp is increased to increase the brightness, the lifetime is further shortened. In addition, since light is emitted from a light source over a wide angular space, there is a limit to improving the light collection efficiency and the light utilization efficiency, and there is a problem in further increasing the brightness of the projection type image display device. is there.

  Therefore, it is possible to use a solid light source such as an LED or a laser as a light source instead of the lamp. In the case of an LED, the divergence angle of light emitted from the light source is large, but it is advantageous in that it has a long lifetime. On the other hand, if a laser having a small divergence angle of light emitted from the light source is used, the light utilization efficiency can be extremely increased as compared with the lamp. In addition, the lifetime of the laser is much longer than that of the lamp. Further, since the F number of the illumination system and the projection optical system can be reduced, there is an advantage that the apparatus can be downsized.

  As described above, the larger size of the power mirror 5 is advantageous because the degree of freedom of distortion correction and screen position control is increased. Further, by making the power mirror 5 larger, a degree of freedom can be assigned not only for distortion correction and screen position control, but also for correction of various aberrations such as astigmatism and field curvature. The burden of aberration correction can be reduced, the configuration of the refractive lens group 4 can be simplified, and the overall imaging performance can be improved.

  On the other hand, since the power mirror 5 is large in size, it is desirable to manufacture it by resin molding in consideration of productivity. However, in the case of mold molding, due to factors such as uniformity of resin filling into the mold, cooling time, and shape errors due to sink marks, manufacturing errors increase as the molded body increases, and manufacturing costs also increase. From such a viewpoint, it is desirable that the power mirror 5 be as small as possible.

  Further, when bringing the screen position close to the optical axis 10 of the refractive lens group 4, it is necessary to avoid interference between the lower end of the projected image and the principal ray 23 emitted from the refractive lens group 4. When the size of the power mirror 5 is increased, the principal ray 23 is further away vertically from the optical axis 10 of the refractive lens group 4. For this reason, interference between the principal ray 23 emitted from the refractive lens group 4 toward the power mirror 5 and the lower end of the projected image toward the screen 6 is likely to occur. Therefore, it is desirable that the size of the power mirror 5 is smaller from the viewpoint of bringing the screen position closer to the optical axis 10 of the refractive lens group 4.

  In general, as the F number of the projection optical system becomes smaller, it becomes difficult to ensure good imaging performance and distortion performance, and in order to ensure them, the projection optical system becomes larger and the configuration becomes complicated. In the projection type image display apparatus 300 according to Embodiment 3, by using a solid-state light source such as a laser as the light source 1, the F number of the projection optical system is increased, so that it is easy to ensure imaging performance. The size of the refractive lens group 4 can be reduced, the curvature of each lens constituting the refractive lens group 4 can be reduced, and the configuration can be simplified. Further, the power mirror 5 can be downsized. Therefore, interference with the lower end of the projected image hardly occurs, and the height of the portion under the screen 6 can be further reduced.

  In the projection type image display apparatus 300 according to Embodiment 3, the distance Ll between the DMD center and the optical axis 10 of the refractive lens group 4 is 7.2 mm, and the projection magnification M = Di / Dl is 83.87. The distance Li between the center of the projected image and the optical axis 10 of the refractive lens group is 490 mm. In addition, Li / {(Di / Dl) · Ll} in conditional expression (6) is 0.81, Li / {Hl · (Di / Dl)} in conditional expression (7) is 0.59, Ll / Hl in conditional expression (8) is 0.73. Further, the TV distortion is 0.15% or less, which is sufficiently smaller than about 1% which is a guideline of the upper limit allowable value. 16 and 17 are aberration diagrams of the projection type image display apparatus 300. FIG. The maximum value on the vertical axis of this aberration diagram is ± 5 mm.

  As described above, according to the projection-type image display apparatus 300 according to the third embodiment, the oblique projection that irradiates the projection light traveling in the direction having an inclination with respect to the normal line of the screen 6 with a simple configuration. However, it is possible to reduce the depth of the device and reduce the height of the portion under the screen.

  In the third embodiment, points other than the above are the same as in the first or second embodiment.

Embodiment 4 FIG.
Hereinafter, a projection type image display apparatus 400 according to Embodiment 4 of the present invention will be described with reference to FIGS.

  18 and 19 are side views showing an internal configuration and an optical path of the projection type image display apparatus 400 according to Embodiment 4 of the present invention. FIG. 18 shows an internal configuration and an optical path of the projection type image display apparatus 400 when the projection type image display apparatus 400 is installed with the screen 6 oriented in the horizontal direction (left direction in FIG. 18). FIG. 19 shows an internal configuration and an optical path when the projection type image display apparatus 400 is viewed from the front toward the screen. 18 and 19, the same reference numerals are given to the same or corresponding components as those shown in FIG. 1.

  The projection-type image display apparatus 400 according to Embodiment 4 includes two plane mirrors 8 and 7 that fold back the traveling direction of the optical image from the refractive lens group 4 in the middle of the optical path from the refractive lens group 4 to the power mirror 5. Is different from the projection type image display apparatus 100 according to the first embodiment. As shown in FIGS. 18 and 19, the plane mirror 7 is disposed between the screen 6 and the power mirror 5, and the plane mirror 8 is disposed vertically above the power mirror 5. In the fourth embodiment, when the optical path from the refractive lens group 4 to the power mirror 5 is regarded as a straight line without the plane mirrors 8 and 7, the conditional expressions (6) to (8) are expressed as follows. An illumination optical system (light source 1 and optical system 2), a light valve 3, a refractive lens group 4, a power mirror 5, and a screen 6 are arranged so as to satisfy.

  The plane mirror 7 is disposed so that the reflection surface is inclined vertically upward with respect to a horizontal axis parallel to the screen 6 surface, and the plane mirror 8 is a reflection surface with respect to the vertical surface passing through the center of the screen 6. It is arranged inclining vertically downward. In the projection type image display device 400, the projection light emitted from the refractive lens group 4 and reflected by the plane mirror 8 is reflected by the plane mirror 7, further reflected by the power mirror 5, and crosses the projection light directed toward the screen 6. It is configured as follows. Further, with this configuration, the refractive lens group 4 is arranged vertically above the power mirror 5 and on the back side of the screen 6 so that its optical axis is substantially parallel to the screen surface. It is configured so that it can be stored compactly in the housing.

If the angle (°) between the normal line of the plane mirror surface 8 and the horizontal plane (the upper direction is the positive direction) is θ1, the projection display apparatus 400 may satisfy the following conditional expression (9). desirable.
22 <θ1 <37 (9)

  In the conditional expression (9), when the angle θ1 is less than the lower limit value 22 °, interference between the light beam traveling from the plane mirror 8 to the plane mirror 7 and the power mirror 5 occurs. If the angle θ1 exceeds the upper limit of 37 °, interference between the refractive lens group 4 and the plane mirror 8 and the projection light directed from the power mirror 5 toward the screen 6 occurs.

  The optical characteristics such as the shapes of the refractive lens group 4 and the power mirror 5 in the projection type image display apparatus 400 according to the fourth embodiment are shown in Table 1 shown for the projection type image display apparatus 100 according to the first embodiment. ~ Same as optical data in Table 5.

  As described above, according to the projection type image display apparatus 400 according to the fourth embodiment, the oblique projection that irradiates the projection light traveling in the direction having an inclination with respect to the normal line of the screen 6 is employed. Nevertheless, it is possible to reduce the depth of the device and reduce the height of the portion under the screen.

  The fourth embodiment is the same as the first embodiment except for the points described above.

  In addition, the plane mirrors 7 and 8 in the fourth embodiment can be applied to the configurations of the embodiments other than the first embodiment.

Embodiment 5 FIG.
Hereinafter, a projection type image display apparatus 500 according to Embodiment 5 of the present invention will be described with reference to FIGS. 20 and 21. FIG.

  20 and 21 are side views showing an internal configuration and an optical path of a projection type image display apparatus 500 according to Embodiment 5 of the present invention. FIG. 20 shows an internal configuration and an optical path of the projection type image display apparatus 500 when the projection type image display apparatus 500 is installed with the screen 6 oriented in the horizontal direction (left direction in FIG. 20). FIG. 21 shows an internal configuration and an optical path when the projection type image display apparatus 500 is viewed from the front toward the screen. 20 and 21, the same or corresponding components as those shown in FIG. 1 are denoted by the same reference numerals.

  The projection-type image display device 500 according to Embodiment 5 includes a single plane mirror 7 that turns back the traveling direction of the optical image from the refractive lens group 4 in the middle of the optical path from the refractive lens group 4 to the power mirror 5. This is different from the projection type image display apparatus 100 according to the first embodiment. As shown in FIGS. 20 and 21, the plane mirror 7 is disposed between the screen 6 and the power mirror 5. In the fifth embodiment, the conditional expressions (6) to (8) are satisfied when the optical path from the refractive lens group 4 to the power mirror 5 is regarded as a straight line without the plane mirror 7 interposed. Thus, the illumination optical systems 1 and 2, the light valve 3, and the refractive lens group 4 are arranged.

  The plane mirror 7 is disposed with the reflection surface inclined vertically upward with respect to a horizontal axis parallel to the screen surface, and the projection light emitted from the refractive lens group 4 is reflected by the plane mirror 7. Further, the projection light is reflected by the power mirror 5 and traverses the projection light directed to the screen 6. With this configuration, the refractive lens group 4 can be placed compactly in the casing of the apparatus by being disposed vertically above the power mirror 5.

  In addition, it is desirable that the projection type image display apparatus 500 satisfies the conditional expression (9). In the conditional expression (9), when the angle θ1 is less than the lower limit value 22 °, interference between the light mirror exiting the refractive lens group 4 toward the plane mirror 7 and the power mirror 5 occurs. If the angle θ1 exceeds the upper limit of 37 °, interference between the refractive lens group 4 and the projection light that exits the power mirror 5 and travels toward the screen 6 occurs.

  The optical characteristics such as the shapes of the refractive lens group 4 and the power mirror 5 in the projection type image display apparatus 500 according to the fifth embodiment are shown in Table 6 shown for the projection type image display apparatus 200 according to the second embodiment. ~ Same as optical data in Table 10.

  As described above, according to the projection type image display apparatus 500 according to the fifth embodiment, the oblique projection that irradiates the projection light traveling in the direction having an inclination with respect to the normal line of the screen 6 is employed. Nevertheless, it is possible to reduce the depth of the device and reduce the height of the portion under the screen.

  In the fifth embodiment, points other than those described above are the same as in the first embodiment.

  In addition, the plane mirror 7 in the fourth embodiment can be applied to the configurations of the embodiments other than the first embodiment.

Embodiment 6 FIG.
Hereinafter, a projection type image display apparatus 600 according to Embodiment 6 of the present invention will be described with reference to FIGS.

  FIG. 22 is a side view showing an internal configuration and an optical path of projection type image display apparatus 600 according to Embodiment 6. In FIG. 22, the same reference numerals are given to the same or corresponding components as those shown in FIG. FIG. 23 is a cross-sectional view showing the configuration of the light valve 3 and the refractive lens group 4 of the projection type image display apparatus 600. In FIG. 23, the same reference numerals are given to the same or corresponding components as those shown in FIG.

  Table 16 shows optical data of the optical system of the projection type image display apparatus 600. Tables 17 to 19 show optical data of the lens surfaces S3, S20, and S21 of the refractive lens group 4 of the projection type image display device 600. Table 20 shows optical data of the surface (mirror surface) S22 of the power mirror 5 of the projection type image display apparatus 600. The optical data description method in Tables 16 to 20 is the same as the optical data description method in Tables 1 to 5.

  In the projection type image display apparatus 600 according to Embodiment 6, the light valve 3 has a horizontal axis (optical axis 10) including the intersection of the optical axis 10 of the refractive lens group 4 and a plane obtained by extending the display surface of the light valve 3. A portion (the lower side in FIG. 22) that displays the upper side of the screen of the light valve 3 with the horizontal axis in the direction orthogonal to the axis perpendicular to the plane of the drawing of FIG. It is arranged by rotating by 2.71 ° in a direction away from the lens constituting the group 4 (that is, in a posture in which the lower part of the OBJ in FIG. 23 is moved to the left).

  Here, the effect of the projection type image display apparatus 600 according to the sixth embodiment in which the light valve 3 is rotated will be described. 24 shows a conventional optical system indicated by a broken line in FIG. 7, in which the upper part of the power mirror 5 approaches the screen 6 with the horizontal axis including the surface vertex and parallel to the screen surface as the center. It is a figure which shows the structure in the case of the comparative example rotated in the direction. In this case, the screen position can be closer to the optical axis 10 of the refractive lens group 4 than in the prior art, but the imaging plane is inclined in a direction in which the upper part of the screen is further away from the power mirror 5, and further, as shown in FIG. As a result, a distortion having a convex shape on the upper side of the screen occurs.

  In FIG. 26, the horizontal axis in the direction perpendicular to the paper surface of FIG. 26 including the intersection of the optical axis 10 of the refractive lens group 4 and the plane in which the display surface of the light valve 3 is extended in FIG. FIG. 27 is a diagram showing a configuration in which a portion (the lower side of the light valve 3 in FIG. 26) that displays the upper side of the screen of the light valve 3 is rotated in the direction away from the lenses constituting the refractive lens group 4 as the center.

  In this configuration, in the display surface of the light valve 3, an image is formed at a position closer to the power mirror 5 at a distance along the optical axis 10 of the refractive lens group 4 and farther from the refractive lens group 4. Therefore, it is possible to correct the tilt of the image plane generated in FIG. 24 showing the conventional example. At the same time, as shown in FIG. 27, an image without distortion can be projected.

  As described above, the light valve 3 is centered on the horizontal axis in the direction perpendicular to the paper surface of FIG. 26, including the intersection of the optical axis 10 of the refractive lens group 4 and the plane obtained by extending the light valve 3 display surface. By adopting a rotationally arranged configuration, better imaging performance and distortion performance can be realized.

  In the projection type image display apparatus 600, the F number of the projection optical system is 5, the distance Ll between the DMD center and the optical axis 10 of the refractive lens group 4 is 7.2 mm, and the projection magnification M = Di / Dl is 83.87 times, and the distance Li between the center of the projected image and the optical axis 10 of the refractive lens group is 477.1 mm. In addition, Li / {(Di / Dl) · Ll} in the conditional expression (6) is 0.79, Li / {Hl · (Di / Dl)} in the conditional expression (7) is 0.58, Ll / Hl in conditional expression (8) is 0.73. Further, the TV distortion is 0.35% or less, which is sufficiently smaller than about 1% which is a guideline of the upper limit allowable value. 28 and 29 are aberration diagrams of the projection type image display device 600. FIG. The maximum value on the vertical axis of this aberration diagram is ± 5 mm.

  As described above, according to the projection type image display apparatus 600 according to the sixth embodiment, the oblique projection that irradiates the projection light traveling in the direction having an inclination with respect to the normal line of the screen 6 is employed. Nevertheless, it is possible to reduce the depth of the device and reduce the height of the portion under the screen.

  In the sixth embodiment, points other than those described above are the same as those in the first embodiment.

  Further, the arrangement of the light valve 3 in the sixth embodiment can be applied to the configurations of other embodiments other than the sixth embodiment.

Reference example.
Below, the projection type image display apparatus 650 of a reference example is demonstrated, referring FIGS. 30-33.

  FIG. 30 is a side view showing an internal configuration and an optical path of the projection type image display device 650 of the reference example. In FIG. 30, the same or corresponding components as those shown in FIG. FIG. 31 is a cross-sectional view showing configurations of the light valve 3 and the refractive lens group 4 of the projection type image display device 650. In FIG. 31, the same or corresponding elements as those shown in FIG.

  Table 21 shows optical data of the optical system of the projection type image display device 650. Tables 22 to 24 show optical data of the lens surfaces S3, S20, and S21 of the refractive lens group 4 of the projection type image display device 650. Table 25 shows optical data of the surface (mirror surface) S22 of the power mirror 5 of the projection type image display apparatus 200. The optical data description method in Tables 21 to 25 is the same as the optical data description method in Tables 1 to 5 described in the first embodiment.

  In the projection type image display device 650, the F number of the projection optical system is 5, the distance Ll between the DMD center and the optical axis 10 of the refractive lens group 4 is 5.42 mm, and the projection magnification M = Di / Dl is 83.87 times, and the distance Li between the center of the projected image and the optical axis 10 of the refractive lens group is 454.4 mm. In addition, Li / {(Di / Dl) · Ll} in the conditional expression (6) is 1.0, Li / {Hl · (Di / Dl)} in the conditional expression (7) is 0.55, Ll / Hl in conditional expression (8) is 0.55. The TV distortion is 0.21% or less, which is sufficiently smaller than about 1%, which is a guideline for the upper limit allowable value. 30 and 31 are aberration diagrams of the projection type image display device 650. FIG. The maximum value on the vertical axis of this aberration diagram is ± 5 mm.

  In the configuration of this reference example, Li / {(Di / Dl) · Ll} in conditional expression (6) is 1.0, which does not satisfy conditional expression (6).

  In the reference example, points other than those described above are the same as those in the first embodiment.

Embodiment 7 FIG.
Hereinafter, a projection type image display apparatus 700 according to Embodiment 7 of the present invention will be described with reference to FIGS.

  FIG. 34 is a side view showing the internal configuration and optical path of the projection type image display apparatus 700 according to the seventh embodiment. 34, the same reference numerals are given to the same or corresponding components as those shown in FIG. FIG. 35 is a cross-sectional view showing the configuration of the light valve 3 and the refractive lens group 4 of the projection type image display apparatus 700. 35, the same reference numerals are given to the same or corresponding components as those shown in FIG.

  Table 26 shows optical data of the optical system of the projection type image display apparatus 700. Tables 27 to 29 show optical data of the lens surfaces S3, S20, and S21 of the refractive lens group 4 of the projection type image display apparatus 700. Table 30 shows optical data of the surface (mirror surface) S22 of the power mirror 5 of the projection type image display apparatus 700. The optical data description method in Tables 26 to 30 is the same as the optical data description method in Tables 1 to 5 described in the first embodiment.

  In the projection type image display apparatus 700, the F number of the projection optical system is 5, the distance Ll between the center of the DMD and the optical axis 10 of the refractive lens group 4 is 5.42 mm, and the projection magnification M = Di / Dl is 83.87 times, and the distance Li between the center of the projected image and the optical axis 10 of the refractive lens group 4 is 445.3 mm. In addition, Li / {(Di / Dl) · Ll} in conditional expression (6) is 0.98, Li / {Hl · (Di / Dl)} in conditional expression (7) is 0.54, Ll / Hl in conditional expression (8) is 0.55. Further, the TV distortion is 0.24% or less, which is sufficiently smaller than about 1% which is a guideline of the upper limit allowable value. 36 and 37 are aberration diagrams of the projection type image display apparatus 700. FIG. The maximum value on the vertical axis of this aberration diagram is ± 5 mm.

  As described above, according to the projection type image display apparatus 700 according to the seventh embodiment, the oblique projection that irradiates the projection light traveling in the direction having the inclination with respect to the normal line of the screen 6 is employed. Nevertheless, it is possible to reduce the depth of the device and reduce the height of the portion under the screen.

  In the seventh embodiment, points other than those described above are the same as those in the first embodiment.

Embodiment 8 FIG.
Hereinafter, a projection type image display apparatus 800 according to Embodiment 8 of the present invention will be described with reference to FIGS.

  FIG. 38 is a side view showing the internal configuration and optical path of projection-type image display apparatus 800 according to Embodiment 8. 38, the same reference numerals are given to the same or corresponding components as those shown in FIG. FIG. 39 is a cross-sectional view showing the configuration of the light valve 3 and the refractive lens group 4 of the projection type image display apparatus 800. In FIG. 39, the same or corresponding elements as those shown in FIG.

  Table 31 shows optical data of the optical system of the projection type image display apparatus 800. Tables 32 to 34 show optical data of the lens surfaces S3, S20, and S21 of the refractive lens group 4 of the projection type image display device 800. Table 35 shows optical data of the surface (mirror surface) S22 of the power mirror 5 of the projection type image display device 800. The optical data description method in Tables 31 to 35 is the same as the optical data description method in Tables 1 to 5 described in the first embodiment.

  In the projection type image display device 800, the F number of the projection optical system is 5, the distance Ll between the DMD center and the optical axis 10 of the refractive lens group 4 is 5.9 mm, and the projection magnification M = Di / Dl is 83.87 times, and the distance Li between the center of the projected image and the optical axis 10 of the refractive lens group is 470.9 mm. Further, Li / {(Di / Dl) · Ll} in the conditional expression (6) is 0.95, Li / {Hl · (Di / Dl)} in the conditional expression (7) is 0.57, Ll / Hl in conditional expression (8) is 0.60. Further, the TV distortion is 0.27% or less, which is sufficiently smaller than about 1% which is a guideline of the upper limit allowable value. 40 and 41 are aberration diagrams of the projection-type image display device 800. FIG. The maximum value on the vertical axis of this aberration diagram is ± 5 mm.

  As described above, according to the projection type image display apparatus 800 according to the eighth embodiment, the oblique projection that irradiates the projection light traveling in the direction having an inclination with respect to the normal line of the screen 6 is employed. Nevertheless, it is possible to reduce the depth of the device and reduce the height of the portion under the screen.

  In the eighth embodiment, points other than the above are the same as in the first embodiment.

Embodiment 9 FIG.
Hereinafter, a projection type image display apparatus 900 according to Embodiment 9 of the present invention will be described with reference to FIGS. 42 to 45.

  FIG. 42 is a side view showing an internal configuration and an optical path of the projection type image display apparatus 900 according to the ninth embodiment. 42, the same reference numerals are given to the same or corresponding components as those shown in FIG. FIG. 43 is a cross-sectional view showing the configuration of the light valve 3 and the refractive lens group 4 of the projection type image display apparatus 200. In FIG. 43, the same or corresponding elements as those shown in FIG.

  Table 36 shows optical data of the optical system of the projection type image display apparatus 900. Tables 37 to 39 show optical data of the lens surfaces S3, S20, and S21 of the refractive lens group 4 of the projection type image display apparatus 900. Table 40 shows optical data of the surface (mirror surface) S22 of the power mirror 5 of the projection type image display apparatus 900. The optical data description method in Tables 36 to 40 is the same as the optical data description method in Tables 1 to 5 described in the first embodiment.

  In the projection type image display apparatus 900, the F number of the projection optical system is 5, the distance Ll between the DMD center and the optical axis 10 of the refractive lens group 4 is 5.9 mm, and the projection magnification M = Di / Dl is 83.87 times, and the distance Li between the center of the projected image and the optical axis 10 of the refractive lens group is 470.0 mm. In addition, Li / {(Di / Dl) · Ll} in conditional expression (6) is 0.93, and Li / {Hl · (Di / Dl)} in conditional expression (7) is 0.56. Ll / Hl in conditional expression (8) is 0.60. Further, the TV distortion is 0.35% or less, which is sufficiently smaller than about 1% which is a guideline of the upper limit allowable value. 44 and 45 are aberration diagrams of the projection type image display apparatus 900. FIG. The maximum value on the vertical axis of this aberration diagram is ± 5 mm.

  As described above, according to the projection type image display apparatus 900 according to the ninth embodiment, the oblique projection that irradiates the projection light traveling in the direction having the inclination with respect to the normal line of the screen 6 while adopting the oblique projection is adopted. Despite this, it is possible to reduce the depth of the device and reduce the height of the portion under the screen.

  In the ninth embodiment, points other than those described above are the same as those in the first embodiment.

Embodiment 10 FIG.
A projection type image display apparatus 1000 according to Embodiment 10 of the present invention will be described below with reference to FIGS.

  FIG. 46 is a side view showing an internal configuration and an optical path of projection type image display apparatus 1000 according to Embodiment 10. In FIG. 46, the same or corresponding elements as those shown in FIG. FIG. 47 is a cross-sectional view showing the configuration of the light valve 3 and the refractive lens group 4 of the projection type image display apparatus 1000. In FIG. 47, the same reference numerals are given to the same or corresponding components as those shown in FIG.

  Table 41 shows optical data of the optical system of the projection type image display apparatus 1000. Tables 42 to 44 show optical data of the lens surfaces S3, S20, and S21 of the refractive lens group 4 of the projection image display apparatus 1000. Table 45 shows optical data of the surface (mirror surface) S22 of the power mirror 5 of the projection type image display apparatus 1000. The optical data description method in Tables 41 to 45 is the same as the optical data description method in Tables 1 to 5 described in the first embodiment.

  In the projection image display apparatus 1000 according to the tenth embodiment, the light valve 3 has a horizontal axis (optical axis 10) including an intersection of the optical axis 10 of the refractive lens group 4 and a plane obtained by extending the display surface of the light valve 3. A portion (the lower side in FIG. 46) that displays the upper side of the screen of the light valve 3 with the horizontal axis in the direction orthogonal to the axis perpendicular to the paper surface on which FIG. It is arranged by rotating 1.33 ° in a direction away from the lens constituting the group 4 (that is, in a posture in which the lower part of the OBJ in FIG. 23 is moved to the left).

  In the projection type image display apparatus 1000, the F number of the projection optical system is 5, the distance Ll between the DMD center and the optical axis 10 of the refractive lens group 4 is 6.5 mm, and the projection magnification M = Di / Dl is The distance Li between the center of the projected image and the optical axis 10 of the refractive lens group 4 is 479.7 mm. In addition, Li / {(Di / Dl) · Ll} in conditional expression (6) is 0.88, and Li / {Hl · (Di / Dl)} in conditional expression (7) is 0.58. In the conditional expression (8), Ll / Hl is 0.66. Further, the TV distortion is 0.25% or less, which is sufficiently smaller than about 1% which is a guideline of the upper limit allowable value. 48 and 49 are aberration diagrams of the projection image display apparatus 1000. FIG. The maximum value on the vertical axis of this aberration diagram is ± 5 mm.

  As described above, according to the projection type image display apparatus 1000 according to the tenth embodiment, the oblique projection that irradiates the projection light traveling in the direction having the inclination with respect to the normal line of the screen 6 is employed. Nevertheless, it is possible to reduce the depth of the device and reduce the height of the portion under the screen.

  In the tenth embodiment, points other than those described above are the same as those in the first embodiment.

Embodiment 11 FIG.
A projection type image display apparatus 1100 according to Embodiment 11 of the present invention will be described below with reference to FIGS.

  FIG. 50 is a side view showing the internal configuration and optical path of projection-type image display apparatus 1100 according to Embodiment 11. 50, the same reference numerals are given to the same or corresponding components as those shown in FIG. FIG. 51 is a cross-sectional view showing configurations of the light valve 3 and the refractive lens group 4 of the projection type image display apparatus 1100. 50, the same reference numerals are given to the same or corresponding components as those shown in FIG.

  Table 46 shows optical data of the optical system of the projection type image display apparatus 1100. Tables 47 to 49 show optical data of the lens surfaces S3, S20, and S21 of the refractive lens group 4 of the projection type image display apparatus 1100. Table 50 shows optical data of the surface (mirror surface) S22 of the power mirror 5 of the projection type image display apparatus 1100. The optical data description method in Tables 46 to 50 is the same as the optical data description method in Tables 1 to 5 described in the first embodiment.

  In the projection type image display apparatus 1100 according to the eleventh embodiment, the light valve 3 has a horizontal axis (optical axis 10) including the intersection of the optical axis 10 of the refractive lens group 4 and a plane obtained by expanding the display surface of the light valve 3. A portion (the lower side in FIG. 50) that displays the upper side of the screen of the light valve 3 with the horizontal axis in the direction orthogonal to the axis perpendicular to the paper surface on which FIG. It is arranged to rotate 2.11 ° in a direction away from the lens constituting the group 4 (that is, in a posture in which the lower part of the OBJ in FIG. 23 is moved to the left).

  In the projection type image display apparatus 1100, the F number of the projection optical system is 5, the distance Ll between the center of the DMD and the optical axis 10 of the refractive lens group is 7.0 mm, and the projection magnification M = Di / Dl is 83. The distance Li between the center of the projected image and the optical axis 10 of the refractive lens group is 487.3 mm. In addition, Li / {(Di / Dl) · Ll} in conditional expression (6) is 0.83, and Li / {Hl · (Di / Dl)} in conditional expression (7) is 0.59. Ll / Hl in conditional expression (8) is 0.71. Further, the TV distortion is 0.32% or less, which is sufficiently smaller than about 1% which is a guideline of the upper limit allowable value. 52 and 53 are aberration diagrams of the projection image display apparatus 1100. FIG. The maximum value on the vertical axis of this aberration diagram is ± 5 mm.

  As described above, according to the projection type image display apparatus 1100 according to the eleventh embodiment, the oblique projection that irradiates the projection light traveling in the direction inclined with respect to the normal line of the screen 6 is employed. Nevertheless, it is possible to reduce the depth of the device and reduce the height of the portion under the screen.

  In the eleventh embodiment, points other than those described above are the same as in the first embodiment.

Embodiment 12 FIG.
Hereinafter, a projection type image display apparatus 1200 according to Embodiment 12 of the present invention will be described with reference to FIGS. 54 and 55. FIG.

  FIG. 54 is a side view showing an internal configuration and an optical path when the projection type image display apparatus 1200 according to the twelfth embodiment is seen from the horizontal and horizontal direction. FIG. 55 is a side view showing the projection type image display apparatus 1200 in the vertical upward direction. It is a top view which shows an internal structure at the time of seeing from and optical path. In each of FIG. 54 and FIG. 55, the same reference numerals are given to the same or corresponding components as those shown in FIG.

  The projection-type image display apparatus 1200 according to the twelfth embodiment includes a single plane mirror 11 that turns back the traveling direction of the optical image from the refractive lens group 4 in the middle of the optical path from the refractive lens group 4 to the power mirror 5. This is different from the projection type image display apparatus 800 according to the eighth embodiment. The plane mirror 11 bends the projection light emitted from the refractive lens group 4 in the horizontal direction, and disposes the refractive lens group 4 between the screen 6 and the power mirror 5 as a physical positional relationship. The system can be stored compactly in the housing.

Assuming that the angle (°) formed by the projection optical axis before and after being bent by the plane mirror 11 is θ2, it is desirable that the projection type image display apparatus 1200 satisfies the following conditional expression (10).
20 ≦ θ2 ≦ 90 (10)

  In the conditional expression (10), if the angle θ2 is less than the lower limit value 20 °, interference between the refractive lens group 4 and the light valve 3 and the power mirror 5 and the projection light from the power mirror 5 toward the screen 6 occurs. If the angle θ2 exceeds the upper limit of 90 °, the refractive lens group 4 and the light valve 3 are located away from the power mirror 5 and the projection optical system cannot be arranged in a compact manner.

  The optical characteristics such as the shape of the refractive lens group 4 and the power mirror 5 in the projection image display apparatus 1200 according to the twelfth embodiment are shown in Table 31 shown for the projection image display apparatus 800 according to the eighth embodiment. ~ Same as optical data in Table 35.

  As described above, according to the projection-type image display apparatus 1200 according to the twelfth embodiment, the oblique projection that irradiates the projection light traveling in the direction inclined with respect to the normal line of the screen 6 is employed. Nevertheless, it is possible to reduce the depth of the device and reduce the height of the portion under the screen.

  In the twelfth embodiment, points other than those described above are the same as in the eighth embodiment.

Modified example.
In each of the above embodiments, the case where the projection type image display apparatus is a rear projection type in which the screen is transmissive is described. However, the present invention is not limited to the rear projection type, and the present invention is a front projection type. It can also be applied.

  Moreover, it is also possible to constitute a multi-screen composed of a plurality of screens by combining the projection type image display apparatus of the present invention so as to be aligned vertically, horizontally, or vertically and horizontally.

It is a side view which shows the internal structure and optical path of the projection type image display apparatus concerning Embodiment 1 of this invention. 3 is a cross-sectional view showing a configuration of a light valve and a refractive lens group of the projection type image display apparatus according to Embodiment 1. FIG. It is a figure for demonstrating operation | movement of DMD in the comparative example whose offset amount of DMD center position with respect to the optical axis of a refractive lens group is zero. It is a figure which shows schematically the structure in the comparative example which uses a total reflection prism, and the optical path of illumination light and projection light. It is a figure for demonstrating operation | movement of DMD in Embodiment 1 in which the offset of DMD center position with respect to the optical axis of a refractive lens group exists. It is a figure which shows schematically the optical path of the illumination light and projection light in the case of Embodiment 1 which does not use a total reflection prism. FIG. 2 is a diagram schematically showing a positional relationship between components of the projection type image display apparatus according to Embodiment 1. FIG. 6 is an aberration diagram (part 1) of the projection-type image display device according to the first embodiment. FIG. 6 is an aberration diagram (part 2) of the projection-type image display device according to the first embodiment. It is a side view which shows the internal structure and optical path of the projection type image display apparatus concerning Embodiment 2 of this invention. FIG. 6 is a cross-sectional view showing a configuration of a light valve and a refractive lens group of a projection type image display apparatus according to Embodiment 2. FIG. 6A is an aberration diagram (part 1) of the projection type image display apparatus according to the second embodiment. FIG. 12 is an aberration diagram (part 2) of the projection-type image display device according to the second embodiment. It is a side view which shows the internal structure and optical path of the projection type image display apparatus concerning Embodiment 3 of this invention. FIG. 6 is a cross-sectional view showing a configuration of a light valve and a refractive lens group of a projection type image display apparatus according to Embodiment 3. FIG. 10 is an aberration diagram (No. 1) of the projection type image display apparatus according to the third embodiment. FIG. 12 is an aberration diagram (part 2) of the projection-type image display device according to the third embodiment. It is a side view which shows the internal structure and optical path of the projection type image display apparatus concerning Embodiment 4 of this invention. It is the figure which looked at the internal structure and optical path of the projection type image display apparatus concerning Embodiment 4 from the screen front or back surface. It is a side view which shows the internal structure and optical path of the projection type image display apparatus concerning Embodiment 5 of this invention. It is the figure which looked at the internal structure and optical path of the projection type image display apparatus concerning Embodiment 5 from the screen front or back surface. It is a side view which shows the internal structure and optical path of the projection type image display apparatus concerning Embodiment 6 of this invention. FIG. 10 is a cross-sectional view showing a configuration of a light valve and a refractive lens group of a projection type image display apparatus according to Embodiment 6. It is a figure which shows schematically the internal structure and optical path in the case of the comparative example which inclined and arrange | positioned the aspherical mirror. It is a figure which shows the distortion of the projection image in the structure of the comparative example of FIG. It is a figure which shows schematically the internal structure and optical path in the case of Embodiment 6 which inclined and arrange | positioned the light valve. It is a figure which shows the distortion of the projection image in the structure of Embodiment 6 shown by FIG. FIG. 10 is an aberration diagram (No. 1) of the projection type image display apparatus according to the sixth embodiment. FIG. 10 is an aberration diagram (No. 2) of the projection type image display apparatus according to the sixth embodiment. It is a side view which shows the internal structure and optical path of the projection type image display apparatus of a reference example. It is sectional drawing which shows the structure of the light valve and refractive lens group of the projection type image display apparatus of a reference example. FIG. 6 is an aberration diagram (No. 1) of the projection type image display apparatus of the reference example. FIG. 6B is an aberration diagram (part 2) of the projection type image display apparatus of the reference example. It is a side view which shows the internal structure and optical path of the projection type image display apparatus concerning Embodiment 7 of this invention. FIG. 10 is a cross-sectional view showing a configuration of a light valve and a refractive lens group of a projection type image display apparatus according to Embodiment 7. FIG. 10A is an aberration diagram (No. 1) of the projection type image display apparatus according to the seventh embodiment. FIG. 10 is an aberration diagram (No. 2) of the projection type image display apparatus according to the seventh embodiment. It is a side view which shows the internal structure and optical path of the projection type image display apparatus concerning Embodiment 8 of this invention. FIG. 10 is a cross-sectional view showing the configuration of a light valve and a refractive lens group of a projection type image display apparatus according to Embodiment 8. FIG. 10A is an aberration diagram (No. 1) of the projection type image display apparatus according to the eighth embodiment. FIG. 10D is an aberration diagram (part 2) of the projection-type image display device according to the eighth embodiment. It is a side view which shows the internal structure and optical path of the projection type image display apparatus concerning Embodiment 9 of this invention. FIG. 10 is a cross-sectional view illustrating the configuration of a light valve and a refractive lens group of a projection type image display apparatus according to Embodiment 9. FIG. 10A is an aberration diagram (No. 1) of the projection image display apparatus according to the ninth embodiment. FIG. 10D is an aberration diagram (part 2) of the projection-type image display device according to the ninth embodiment. It is a side view which shows the internal structure and optical path of the projection type image display apparatus concerning Embodiment 10 of this invention. FIG. 22 is a cross-sectional view illustrating a configuration of a light valve and a refractive lens group of a projection type image display apparatus according to Embodiment 10. FIG. 18 is an aberration diagram (No. 1) of the projection type image display apparatus according to the tenth embodiment. FIG. 20 is an aberration diagram (No. 2) of the projection type image display apparatus according to the tenth embodiment. It is a side view which shows the internal structure and optical path of the projection type image display apparatus concerning Embodiment 11 of this invention. FIG. 22 is a cross-sectional view showing a configuration of a light valve and a refractive lens group of a projection type image display apparatus according to Embodiment 11. FIG. 20A is an aberration diagram (No. 1) of the projection image display apparatus according to the eleventh embodiment. FIG. 20A is an aberration diagram (No. 2) of the projection image display apparatus according to the eleventh embodiment. It is a side view which shows the internal structure and optical path of the projection type image display apparatus concerning Embodiment 12 of this invention. FIG. 20 is a top view showing an internal configuration and an optical path of a projection type image display apparatus according to Embodiment 12.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source, 2 Optical system, 3 Light valve, 4 Refraction lens group, 5 Power mirror, 6 Screen, 7, 8 Plane mirror, 10 Optical axis of refraction lens group, 11 Plane mirror, 21, 22, 23 Refraction lens group Chief rays going to the power mirror, 31, 32, 33 chief rays going from the power mirror to the screen, 40 DMD reference plane, 41 OFF-state micromirror, 42 ON-state micromirror, 50 illumination optical axis, 51 heading to DMD Illumination light, 60 projection optical axis, 61 projection light from DMD, 70 OFF light optical axis, 71 OFF light, 80 total reflection prism, 81 first prism, 82 second prism, 90 illumination light, 91 projection light 131, 132, 133 chief rays from the power mirror to the screen, 100, 200, 300, 400, 500, 6 00, 700, 800, 900, 1000, 1100, 1200 Projection-type image display device.

Claims (10)

An illumination optical system including a light source;
A reflection type light valve that emits light from the illumination optical system as a light image;
A projection optical system for enlarging and projecting the optical image emitted from the light valve;
A screen on which an optical image magnified by the projection optical system is projected,
The projection optical system is
A refractive lens group for enlarging a light image from the light valve;
Has a light reflecting surface of the free-form surface, and a power mirror having power to expand reflected by the light reflecting surface of the free-form surface optical images from the refracting lens group,
The light valve is disposed by offsetting the center position of the light valve in a predetermined direction from the optical axis of the refractive lens group,
The diagonal dimension of the light valve is Dl,
The dimension of the side of the light valve in the offset direction is H1,
The diagonal dimension of the projected image on the screen is Di,
The distance from the center of the light valve to the optical axis of the refractive lens group is L1,
When the distance from the center of the projected image on the screen to the optical axis of the refractive lens group is Li,
The projection optical system has the following conditional expression 0.8 ≦ Li / {(Di / Dl) · Ll} <1.0.
Li / {Hl · (Di / Dl)}> 0.5
Ll / Hl ≧ 0.54
Satisfied ,
The optical image magnified and reflected by the free-form light reflecting surface proceeds in a direction inclined with respect to the normal line of the screen toward the back surface of the screen, and is projected on the back surface of the screen. In addition, the refraction lens group and the power mirror are arranged . The direction of the offset is vertically downward when the projection-type image display device is installed with the screen directed horizontally.
The projection image display apparatus according to claim 1, wherein the side of the light valve in the offset direction is a short side of the light valve. The refractive lens group includes a plurality of lenses,
Wherein one or more surfaces of a plurality of lenses, projection type image display apparatus according to claim 1 or 2, characterized in that a free-form surface. The front surface of the lens closest to the power mirror in the refractive lens group, a projection type image display apparatus according to any one of claims 1 to 3, characterized in that the free-form surface. In the middle of the optical path from the refractive lens group to the power mirror, a plane mirror that folds the traveling direction of the optical image from the refractive lens group is interposed,
When the optical path from the refractive lens group to the power mirror is regarded as a straight line without the plane mirror being interposed, the illumination optical system, the light valve, and the refractive lens group are set so as to satisfy the conditional expression. projection type image display apparatus according to any one of the arrangement was from claim 1 to 4. The projection image display apparatus according to claim 5 , wherein a plurality of the plane mirrors are arranged. The illumination optical system, the light valve, and the refractive lens group are arranged between the lower end and the upper end of the screen in a positional relationship when the projection type image display device is installed with the screen oriented in the horizontal direction. projection type image display apparatus according to claim 5 or 6, characterized in Rukoto. The illumination optical system, the light valve, and the refractive lens group, a projection type image display apparatus according to claim 5, characterized in that disposed between the power mirror and the screen to 7 . The light valve has an upper side of the screen of the light valve centered on a horizontal axis in a direction orthogonal to the optical axis, including an intersection of an optical axis of the refractive lens group and a plane obtained by extending the display surface of the light valve. projection type image display apparatus according to claim 1, characterized in that it is arranged in a rotated away a portion to be displayed from the refracting lens group attitude to 8. The light source, projection type image display apparatus according to claim 1, characterized in that it comprises a plurality of solid state light source groups having different wavelength bands to 9.

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