JP3757222B2 - Projection display - Google Patents

Description

  The present invention relates to a projection display device, and more particularly to improvement of an optical system for illuminating an image display element.

  A projection display device is known as a device for easily realizing a large screen image. This uses an image display element such as a liquid crystal panel or a digital mirror device (DMD) as a display panel, illuminates the display panel with an illumination optical system using light from a light source, and screens the image on the display panel with a projection lens. It is projected on the screen and enlarged. In this illumination optical system, an optical element called an integrator is provided for the purpose of efficiently illuminating the display panel surface using light from a light source efficiently. Integrators are known to be rod-shaped or fly-eye lens-shaped, and fly-eye lenses are used mainly for devices using liquid crystal panels, and rod integrators are used for devices using DMD. There are many. Projection type display devices are generally demanded from the market for small size, light weight, low cost, and high brightness, and a single plate type using one DMD as a display panel is very promising.

  By the way, the DMD, which is a display panel, reflects and reflects the light from the light source by controlling the inclination of the micromirrors laid between about 500,000 to 1.31 million per device by turning the power on and off. The light is projected onto the screen, and the contrast of the image is expressed by controlling the number of on and off times. In the device structure, the yoke is held in a space by being pulled by an integrally formed soft and thin string-like hinge. The mirror and the yoke are rotated around the diagonal axis by electrostatic force, and the yoke comes into contact with the substrate at ± 10 degrees to ± 12 degrees to be in a stable state. An SRAM cell composed of five transistors drives one mirror. A mirror part is formed on the same SRAM through a CMP oxide film manufactured with a 0.72 μm rule, twin-well CMOS, double-layer metal. In such a DMD, since the size of the micromirror that constitutes one pixel is unchanged, the size of the device changes according to the resolution. For example, if the micromirror is 13.68 μm square, the effective display area is 0.55 inches diagonal for SVGA resolution (800 x 600), whereas the effective display area is 0.7 inches diagonal for XGA (1024 x 768). become. That is, the effective display area increases as the resolution becomes higher.

  By the way, the illumination optical system of the projection display apparatus, the optical components constituting the illumination optical system, and parameters thereof are optimized and designed so that various performances of the apparatus are good. For example, in a DMD projection display device having a diagonal size of 1.3 inches, the illumination optical system uniformly and efficiently illuminates the entire area of the 1.3 inch DMD. Therefore, when the DMD is replaced with a 0.9 inch size, the DMD becomes smaller than the illumination range, and the use efficiency of the light beam is reduced. Conversely, when a DMD larger than 1.3 inches is replaced, the illumination range is too small and the amount of light is insufficient. Thus, under the conditions of various parameters that have been optimized, it is difficult to replace the DMD with a different size.

  In response to such a request, in Patent Document 1, as shown in FIG. 9, the light beam emitted from the light source 101 is condensed on the integrator 103 by the reflecting mirror 102, and the light beam emitted through the integrator 103 is converted into the image display element. The relay lens 106 for irradiating the display panel 107 is configured with at least two lenses 106A and 106B, and the distance between the two lenses 106A and 106B on the optical axis is made variable, so that the relay lens The zoom configuration changes the focal length of 106. By changing and adjusting the focal length of the relay lens 106, it is possible to adjust the brightness and illumination range of the display panel. However, in the configuration of Patent Document 1, there is a problem that the relay lens 106 requires only one lens in the normal configuration, but at least two or more lenses are required, which increases the cost, and at the same time the weight of the projection display device. There is a problem that becomes heavy. In addition, optical components such as dichroic mirrors and filters are required to form the R, G, and B color lights necessary for color display, but ensure a movable space for moving the lens. It is necessary, and a physical space must be secured so as not to interfere with the optical components that separate R, G, and B, which is not preferable because the apparatus is large. Furthermore, since the combined focal length changes due to the movement of the two lenses, the tilt angle of the light beam incident on the display panel may change, which may cause a decrease in contrast.

On the other hand, Patent Document 2 proposes a technique in which an illumination device that reflects light emitted from a light source is provided with a total reflection mirror provided with a light beam emitting portion having a transparent central portion. In this patent document 2, a display device is displayed with light reflected by a reflector and transmitted through a light beam emitting part, and a light beam other than the light beam emitting part is reflected by a total reflection mirror and reflected again by a reflector, and then the light beam emitting part. By adopting a configuration that transmits light, it is possible to improve brightness by improving the light utilization rate in the display device, and to achieve a simple configuration and a small size and light weight.
JP 2003-15102 A JP 2003-15219 A

  Although the technique of Patent Document 2 realizes improvement of the light utilization rate, the minimum diameter of the transparent (opening) part of the light beam emitting part is set so that light that cannot be emitted from the illumination device is not generated. Thus, the size of the light beam emitting portion is uniquely determined. This is because the change in the size of the display panel such as the DMD as described above is not taken into consideration. For this reason, the technique of Patent Document 2 is effective for a display panel of a specific size. It is difficult to solve the problems described above for the changed display panel.

  It is an object of the present invention to provide an optical system for a projection display apparatus that can mount display panels of a plurality of sizes with the same optical system and that has almost no deterioration in performance.

  The present invention includes a light source, a condensing unit that condenses the light beam from the light source, a rod integrator that guides the light beam collected by the condensing unit from the incident surface toward the exit surface, and an image to be projected. In a projection display device having an image display element to be displayed and a relay lens for illuminating by forming a light beam emitted from the exit surface of the rod integrator on the image display element, the incident surface and the exit surface of the rod integrator Opening members each having an opening region and a reflection region around the opening region are disposed, and at least the opening member disposed on the emission surface has a configuration in which the opening size can be changed according to the size of the effective display region of the image display element. It is characterized by being.

According to the present invention, by preparing a plurality of types of exit side opening members arranged on at least the exit surface of the rod integrator and exchanging them, it is possible to cope with different display panels in the same optical system. There is an effect that a high projection display device can be obtained. In addition, almost all of the light incident on the rod integrator due to the reflection at the opening members on the incident side and the emission side can be used for illumination of the display panel, and the light utilization efficiency can be improved.

  In the present invention, the opening area of the opening member on the exit surface has an opening shape similar to the effective display area of the image display element. For example, it is preferable that the opening area of the opening member arranged on the incident surface is circular, and the opening area of the opening member arranged on the emitting surface is rectangular. Further, the opening member disposed on at least the exit surface of the rod integrator is configured to be removable by replacing a plurality of opening members having different shapes and dimensions of the opening region. In these cases, the opening member has a configuration in which an opening region is opened in a part of a plate member having an inner surface as a reflecting surface, and the inner surface side is attached to the rod integrator with the incident surface and the emitting surface of the rod integrator facing each other. To do. Or you may comprise the opening member arrange | positioned at an entrance plane with the reflecting film provided in the entrance plane of the rod integrator.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a configuration diagram of Embodiment 1 of the projection display apparatus of the present invention. In FIG. 1, the light source 1 is composed of a high-pressure mercury lamp. Other than the high-pressure mercury lamp, a white light source such as a metal halide lamp can be used. Further, by combining the light source 1 with the ellipsoidal reflecting mirror 2 as the light condensing means and arranging the light source 1 in the vicinity of the first focal point of the reflecting mirror 2, the luminous flux emitted from the light source 1 is the second of the reflecting mirror 2. It is condensed as convergent light near the focal point. The incident surface of the rod integrator 3 is disposed at the second focal point. As shown in FIG. 2, the rod integrator 3 is made of prismatic glass, and includes an entrance surface 3a and an exit surface 3b opposite to the entrance surface 3a. The surface is configured as a quadrangular prism whose surface is optically polished. The rod integrator 3 may be made of optical resin other than glass. In addition to the quadrangular prism, a cylindrical shape or a polygonal prism having five or more prisms may be used. Furthermore, the reflecting mirror may be configured in a cylindrical shape. A relay lens 6 is disposed opposite to the exit surface 3 b of the rod integrator 3, and the display panel 7 is illuminated by forming an image of light emitted from the exit surface of the rod integrator 3. Here, the display panel 7 is composed of a transmissive liquid crystal panel. The image displayed on the display panel 7 illuminated by the illumination light is enlarged and projected on the screen 9 by the projection lens 8.

  At the end of the rod integrator 3 on the incident surface 3a side, an incident side opening member 4 made of a reflecting member having a circular opening region 4a is disposed. Further, an exit-side opening member 5 made of a reflective member having a rectangular opening region 5a is disposed at the end on the exit surface 3b side of the rod integrator. As shown in FIG. 3A, the incident side opening member 4 is formed of a reflector having the same rectangular shape as the outer shape of the rod integrator 3, and a circular shape having a size smaller than the outer shape at the center of the reflector. An opening region 4a is opened, and light is transmitted through the opening region 4a. In addition, a reflection region 4b is formed around the periphery. As shown in FIG. 3B, the exit-side opening member 5 is composed of a reflector having the same rectangular shape as the outer shape of the rod integrator 3, and is displayed with a dimension smaller than the outer shape at the center of the reflector. A rectangular opening area 5a similar to the effective display area of the panel 7 is opened, and light is transmitted through the opening area 5a. In addition, a reflection region 5b is formed around the periphery.

  Here, as the incident side opening member and the emission side opening member, for example, a sheet glass in which an aluminum thin film is formed leaving an opening region of a required shape can be used. Alternatively, a sheet metal having a metal opening formed with an aluminum thin film may be used. Each of the opening members 4 and 5 is integrally attached with a plurality of spring pieces 4c and 5c in the plate thickness direction along the periphery, and the rod integrator is utilized by using these spring pieces 4c and 5c. 3 can be attached to and detached from the respective end portions on the incident surface side and the emission surface side. In the present invention, in particular, with respect to the exit side opening member 5, the dimensions of the opening area 5a are different corresponding to a plurality of display panels having different effective display area sizes as shown in FIGS. Plural kinds of exit side opening members 51 and 52 are prepared, and these opening members 51 and 52 are exchanged so as to be detachable from the rod integrator 3.

  In this projection display device, light beams from the light source 1 and the reflecting mirror 2 enter the incident surface 3 a of the rod integrator 3 through the circular opening region 4 a of the incident side opening member 4. The incident light beam repeats total reflection on the inner surfaces of the four side surfaces inside the rod integrator 3 to reach the exit surface 3b of the rod integrator 3 as uniform illumination light. After that, the effective display area which is emitted through the rectangular opening area 5a of the emission side opening member 5 arranged on the emission surface side and which displays the image of the display panel 7 by the image forming action by the relay lens 6 is illuminated. Then, the image formed on the display panel 7 is enlarged and projected on the screen 9 by the projection lens 8.

  Here, the shape of the opening area 5a of the emission side opening member 5 is similar to the effective display area of the display panel 7, that is, the vertical and horizontal dimension ratios thereof are the same, and at the same time, the emission surface 3b of the rod integrator 3 and the display panel 7 The focal length of the relay lens 6 and the position where the relay lens 6 is arranged are selected so as to be in an optical agreement with each other. That is, the parameters of the relay lens 6 are set so that the exit surface 3 b of the rod integrator 3 is multiplied by the projection magnification m by the relay lens 6 and imaged on the display panel 7. By doing so, the illumination information of the exit surface 3b of the rod integrator 3, that is, the uniformity of illumination and the shape of illumination light are transmitted to the display panel 7.

  Next, the optical operation of the rod integrator 3 and each of the entrance side and exit side opening members 4 and 5 will be described in detail with reference to FIG. In the first embodiment, consider a case where, for example, the projection display device corresponds to two types of X1 inch and X2 inch (X1> X2) in terms of the size of the effective display surface of the display panel 7. As shown in FIG. 4A, if the focal length of the relay lens 6 is f and the magnification is m, the size of the relay lens 6 on the exit surface of the rod integrator 3 (here, shown in FIG. 3B). If the diagonal dimension of the opening region 5a of the exit-side opening member 5 is y, the display panel 7 is enlarged to a size of my. If the diagonal dimension of the display panel 7 is X1 as shown in FIG. 4B, the diagonal dimension y of the opening region 5a of the exit side opening member 5 of the rod integrator 3 is X1 / m, If the diagonal dimension of the display panel 7 is X2 as shown in FIG. 4C, the diagonal dimension y of the opening region 5a of the emission side opening member 5 is X2 / m. Accordingly, two types of aperture members having an opening area having a diagonal dimension X1 / m and an opening member having an opening area having a diagonal dimension X2 / m are prepared in advance, and these opening members are used as a projection display device. If the relay lens 6 is selected according to the diagonal dimension of the effective display area of the display panel 7 provided in FIG. 5 and is attached to or detached from the rod integrator 3, the relay lens 6 can be replaced with two types having different effective display area dimensions. An illumination optical system corresponding to the display panel can be configured.

  Therefore, in a plurality of types of projection display devices having the same overall optical system configuration but different display panel configurations, the exit-side opening member 5 of the rod integrator 3 simply corresponds to the size of the effective display area of the display panel 7. By simply replacing them, it becomes possible to construct a projection display device of a different standard using other optical systems as they are. This clearly shows that if three or more kinds of exit side opening members 5 are prepared, it can be applied to a projection display apparatus having three or more different display panels. Can be realized.

  By the way, in the rod integrator 3, as shown in FIG. 5A, when the diagonal dimension of the effective display area of the display panel 7 is X2, the light flux passing through the opening area 5a of the emission side opening member 5 is The display panel 7 is illuminated as it is, but the light beam that has reached the reflection region 5b around the opening region 5a is reflected without being emitted from the emission surface 3b as shown in FIG. Returned to The returned light beam travels through the rod integrator 3 to the incident surface 3a, and then again travels through the rod integrator 3 at the reflecting region 4b of the incident side opening member 4 disposed on the incident surface 3a. The light beam that has reached the exit surface 3b passes through the aperture region 5a and becomes illumination light. Alternatively, the light is reflected again at the reflection region 5b of the emission side opening member 5 and returned to the incident surface 3a. By repeating such reflection, the light beam incident on the incident surface 3a of the rod integrator 3 is finally used as illumination light for the display panel 7 through the opening region 5a of the emission side opening member 5, Even if the light transmission area on the exit surface of the rod integrator 3 is limited by the exit-side opening member 5, illumination can be performed efficiently without causing a decrease in luminous flux.

  In addition, although the circular opening area | region 4a of the incident side opening member 4 is formed circularly on the assumption that the light beam condensed by the reflecting mirror 2 which condenses the light of the light source 1 is circular, the reflecting mirror 2 is formed. When the light beam is converged into an elliptical shape or a polygonal shape depending on the shape, the shape of the opening region may be made different according to the light beam shape. Further, the light source cannot necessarily be configured as a point light source, and the converged light flux has a certain diameter, so that the incident side opening member 4 has a different size of the opening region 4a depending on the type of the light source. It may be exchanged.

  In the first embodiment, the display panel 7 is described assuming a transmissive display device such as a liquid crystal panel. However, the display panel used may be a reflective liquid crystal panel or a display device such as a DMD. Furthermore, although the description has been given of a single panel type display panel, the display panel is not limited to a single panel and may be a three-panel type having an RGB color configuration. Further, for the sake of simplicity, the color forming means is omitted, but a color wheel, a dichroic mirror, or the like can be used as the color forming means.

  FIG. 6 is a diagram illustrating the rod integrator 3A and the opening member in the second embodiment. In the second embodiment, the rod integrator 3A has a cylindrical shape, and a circular opening region is formed on the incident surface 3a of the rod integrator 3A as the incident side opening member 4A of the rod integrator 3A in order to reduce the number of parts of the opening member. A reflective film 41 having 4a and the surrounding reflective region 4b is formed by vapor deposition. Similarly to the first embodiment, the exit opening member 5A is configured as a separate member from the rod integrator 3A, and is detachably fitted to the end on the exit surface side of the rod integrator 3A by a spring piece 5c. As shown in FIGS. 7A and 7B, the output side opening member 5A is provided with a rectangular opening area 5a corresponding to the effective display area of the display panel at the center, and a reflection area 5b as a reflection surface around the opening area 5a. Is formed. And corresponding to the dimension of the effective display area of the display panel, a plurality of emission side opening members 5A1 and 5A2 having different dimensions of the opening area 5a are prepared, and these are selected and arranged on the emission surface side of the rod integrator 3A. It becomes possible to arrange | position to an edge part. In the second embodiment, it is not necessary to prepare the incident side opening member 4A as an independent component, and the number of components can be reduced. On the other hand, the exit-side opening member 5A can be configured to be exchangeable in the same manner as in the first embodiment in order to make the opening area different according to the shape and size of the display panel, and a highly versatile projection display device can be obtained. it can.

  In the first and second embodiments, the exit-side opening members 5 and 5A are exchangeable with respect to the rod integrators 3 and 3A, so that the spring pieces 5c that can be fitted to the end portions of the rod integrators 3 and 3A are provided. For example, as shown in FIG. 8, a slit 32 that opens laterally is formed by a frame member 31 that is integrally provided at least at the end of the output side of the rod integrator 3. In addition, the plate-like opening member 5 having the opening region 5a and the reflection region 5b may be inserted into and removed from the slit 32. By exchanging opening members having different sizes of opening regions and inserting them into the slits 32, it becomes possible to select a desired opening member and arrange it on the rod integrator. Alternatively, although not shown in the figure, by providing a movable slider or the like on the opening member, the opening region can be variably adjusted, so that substantially the same configuration as replacing an opening member having a different size of the opening region. It is good.

It is a block diagram of the projection type display apparatus of this invention. It is a perspective view of the rod integrator and opening member of Example 1. It is a front view of the opening member on the incident side and the emission side. It is a figure for demonstrating the dimension of the opening area | region of the radiation | emission side opening member. It is a figure for demonstrating the light utilization efficiency by an opening member. It is a perspective view of the rod integrator and opening member of Example 2. It is a front view of the opening member on the output side. It is a perspective view of the principal part of a modification. It is a block diagram of the illumination optical system of the conventional projection display apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 2 Reflecting mirror 3 Rod integrator 4, 4A Incident side opening member 5 (51, 52), 5A (5A1, 5A2) Outgoing side opening member 4a, 5a Opening area 4b, 5b Reflecting area 4c, 5c Spring piece 6 Relay lens 7 Display panel 8 Projection lens 9 Screen

Claims (7)

  A light source, a condensing unit that condenses the light beam from the light source, a rod integrator that guides the light beam collected by the condensing unit from the incident surface toward the exit surface, and displays an image to be projected In a projection display device having an image display element and a relay lens that performs illumination by imaging a light beam emitted from the exit surface of the rod integrator on the image display element, Are each provided with an opening member having an opening region and a reflection region around the opening region, and at least the opening member arranged on the light exit surface has an opening dimension that changes according to the size of the effective display region of the image display element. A projection display device characterized in that the configuration is possible.   The projection display device according to claim 1, wherein an opening area of the opening member on the exit surface of the rod integrator has an opening shape similar to an effective display area of the image display element.   The projection display device according to claim 2, wherein the opening area of the opening member disposed on the incident surface is circular, and the opening area of the opening member disposed on the emission surface is rectangular.   The projection according to claim 1, wherein the opening member disposed on at least the exit surface of the rod integrator is detachable by replacing a plurality of opening members having different shapes and dimensions of the opening region. Type display device.   The projection display device according to claim 1, wherein the rod integrator has a polygonal column shape or a cylindrical shape.   The opening member is characterized in that an opening region is opened in a part of a plate member having an inner surface as a reflecting surface, and the inner surface side is attached to the rod integrator with the incident surface and the emitting surface of the rod integrator facing each other. The projection display device according to claim 1.   6. The projection display device according to claim 1, wherein the opening member disposed on the incident surface is formed of a reflective film provided on the incident surface of the rod integrator.

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