JP2005181659A - Rear projection display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To downsize a rear projection type display device.
SOLUTION: A light source 11, a color separation optical system that separates light emitted from the light source 11 into a plurality of color lights, and a color separation optical system that is arranged for each color light, and each color light by the color separation optical system is incident and polarized and separated. A polarized light separating optical system and a projection lens 20 that is arranged for each color light and projects the light emitted from the light valves 18R, 18G, and 18B that are incident on and modulated each colored light emitted from the polarized light separated optical system onto the reflecting mirror 42. The optical axis of the light source light emitted from the light source 11 is orthogonal to a plane formed by the optical axis of each color light traveling by being separated by the color separation optical system.
[Selection] Figure 1

Description

  The present invention relates to a rear projection type display device incorporating a projection type display device using a reflective light valve.

  FIG. 8 is a conceptual diagram of a conventional projection display device.

  FIG. 8 shows a conventional projection display device 100 using a reflective light valve.

  As shown in FIG. 8, the X axis, the Y axis, and the Z axis are orthogonal to each other. The Z axis indicates a direction perpendicular to the paper surface from the bottom to the top of the paper.

  The light source light emitted from the light source 101 composed of a lamp and a concave mirror travels along the optical axis in the X-axis direction, enters the polarization conversion illumination device 102, and is converted into polarized light having a vibration direction parallel to the Z-axis. The polarization conversion illumination device 102 is arranged in the vicinity of a focal point of each lens constituting the first lens plate (not shown) having a plurality of lenses arranged in a matrix shape, and is the same as the first lens plate. A second lens plate (not shown) having a plurality of lenses arranged in a matrix, a polarization conversion device (not shown), and a plurality of light beams emitted from the polarization conversion device are superimposed on a light valve described later. And a condenser lens (not shown) for irradiation. The polarization conversion device includes a prism array in which a combination of a polarization separation unit and a reflective layer arranged in parallel with the polarization separation unit is formed in an array, and an exit surface of polarized light that passes through the polarization separation unit of the prism array Alternatively, it comprises a half-wave plate that changes the vibration direction of either polarized light reflected and emitted by the reflective layer.

  The cross dichroic mirror 103 propagates polarized light having a vibration direction in a direction parallel to the Z-axis emitted from the condenser lens, along the optical axis in the Y-axis direction, which is orthogonal to the incident optical axis and opposite to each other. The color is separated into blue) light and mixed light of R (red) light and G (green) light traveling on the optical axis in the −Y axis direction. The cross dichroic mirror 103 includes a dichroic mirror 103B that reflects B light and transmits R light and G light, and a dichroic mirror 103RG that reflects R light and G light and transmits B light. Are arranged so as to be orthogonal to each other and to be perpendicular to the XY plane.

  The color-separated B light is reflected by the deflecting mirror 104, changes its traveling direction, and enters the polarization beam splitter 107B. The light that has entered the polarization beam splitter 107B is reflected by the polarization separation unit, exits from the exit surface, and enters the reflective light valve 108B disposed for the B light.

  The mixed light of the color-separated R light and G light is reflected by the deflecting mirror 105, changes its traveling direction, reflects the G light, and enters the dichroic mirror 106 having the characteristic of transmitting the R light. Color separation into R light. The G light and the R light are incident on the polarization beam splitters 107G and 107R arranged for the respective color lights, reflected by the polarization separation unit, and incident on the reflection type light valves 108G and 108R arranged for the respective color lights. .

  Each color light incident on the light valves 108B, 108G, and 108R arranged for each color light is reflected by being modulated by the color signal, is incident again on the polarization beam splitters 107B, 107G, and 107R, and is separated by the polarization separation unit. To be analyzed. The modulated light extracted as transmitted light is incident on different incident surfaces of the cross dichroic prism 109 constituting the color synthesis optical system. The cross dichroic prism 109 is disposed so that the R light reflecting dichroic film 109R and the B light reflecting dichroic film 109B are orthogonal to each other and perpendicular to the XY plane. Therefore, the R light is reflected by the dichroic film 109R, the B light is reflected by the dichroic film 109B, and the G light is transmitted through both dichroic films, and is color-combined and emitted from the emission surface. The modulated light color-combined by the cross dichroic prism 109 enters the projection lens 110 as an optical axis in a direction parallel to the X axis. The projection lens 110 includes a rear group lens 110A on the incident side and a front group lens 110B on the exit side. Both optical axes are orthogonal. Although not shown, the projection lens 110 has a reflection deflection mirror, and the projection image emitted from the front lens group 110B is projected on an optical axis parallel to the Z axis.

  FIG. 9 is a conceptual diagram showing a longitudinal section of a conventional rear projection display device using the projection display device of FIG.

  FIG. 9 is a view of the projection display device 100 housed in the housing 112 of the rear projection display device when viewed from the rear side of the light source 101 in FIG. 8 in the X-axis direction. Note that the X-axis direction in FIG. 8 and the X-axis direction in FIG. 9 coincide.

  The screen 114 is assembled to the opening of the front surface portion 112A of the housing 112, and the reflection mirror is assembled to the back surface portion 112B of the housing 112.

The projection image projected by the projection lens 110 of the projection display device 100 is incident on the reflection mirror 113, reflected here, and projected onto the screen 114. Since light is emitted from the projection lens 110 in the Z-axis direction, the projection display device 100 is arranged on the slope of the table 111 having a right-angled triangle in order to make the light incident on the reflection mirror 113 (see FIG. 9). ). The optical axis of the light reflected by the reflection mirror 113 enters the screen 114 perpendicularly.
JP 2003-29210 A

  However, in the rear projection display device using the conventional projection display device as shown in FIG. 9, the projection lens 110 is placed on the screen 114 due to physical restrictions from the projection lens 110 to the side surface of the projection display device 100. Therefore, there is a problem that the thickness (length in the front-rear direction) of the rear projection type display device is increased accordingly.

  The present invention has been made in view of such circumstances, and its object is to reduce the size of the rear projection type display device.

  The invention according to claim 1 is a color separation optical system that separates light source light emitted from a light source into a plurality of color lights, and each color light that is arranged for each color light and is color-separated by the color separation optical system. A polarized light separating optical system for separating the polarized light, a projection optical system for projecting light emitted from a light valve that modulates each color light emitted from the polarized light separating optical system to a reflecting mirror, and reflected by the reflecting mirror In a rear projection display device including a screen on which projection light is incident, an optical axis of the light source light incident on the color separation optical system is a plane including each color light color-separated by the color separation optical system. It is characterized by being vertical.

  According to a second aspect of the present invention, in the rear projection display device according to the first aspect, the projection optical system includes a projection lens and a deflection mirror that deflects light incident on the projection lens. To do.

  According to a third aspect of the present invention, in the rear projection type display device according to the first or second aspect, the projection optical system is disposed in the vicinity of the screen.

  According to a fourth aspect of the present invention, in the rear projection display device according to any one of the first to third aspects, the optical axis of light incident on the projection optical system and the projection light emitted from the projection optical system The angle formed with the optical axis is less than 90 degrees.

  According to a fifth aspect of the present invention, in the rear projection type display device according to any one of the first to fourth aspects, the optical axis of the projection light emitted from the projection optical system is a polarization of the polarization separation optical system. It is characterized by being parallel to a plane perpendicular to the separation part.

  According to a sixth aspect of the present invention, in the rear projection type display device according to any one of the first to fourth aspects, the optical axis of the projection light emitted from the projection lens is the polarization separation of the polarization separation optical system. It is characterized by being inclined with respect to a plane perpendicular to the part.

  According to the present invention, the rear projection display device can be reduced in size.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a basic configuration of a projection display device used in a rear projection display device according to a first embodiment of the present invention.

  As shown in FIG. 1, the X axis, the Y axis, and the Z axis are orthogonal to each other. The Z axis is orthogonal to the paper surface and indicates a direction from the lower part of the paper toward the upper part.

  The optical axis of the light source light emitted from the light source 11 including the lamp and the concave mirror travels in a direction parallel to the Z axis, enters the polarization conversion illumination device 12, and travels parallel to the Z axis. The light emitted from the polarization conversion illumination device 12 reflects the B light, reflects the R light and the G light, reflects the R light and the G light, and transmits the B light. The dichroic mirror 13RG having the characteristic is incident on the cross dichroic mirror 13 arranged orthogonal to each other, and the B light whose optical axis travels in the Y direction and the R light and G light whose optical axis travels in the opposite direction are mixed. Color separation into light. The dichroic mirror 13B and the dichroic mirror 13RG are respectively disposed perpendicular to the YZ plane.

  The color-separated B light is reflected by the deflecting mirror 14, the optical axis thereof travels parallel to the XY plane, enters the polarization beam splitter 17B, and is reflected by the polarization separation unit arranged perpendicular to the XY plane. The light enters the reflective light valve 18B arranged for light.

  The mixed light of the color-separated R light and G light is reflected by the deflecting mirror 15, and its optical axis travels parallel to the XY plane in the same manner as the B light, reflects the G light, and transmits the R light. Is incident on the dichroic mirror 16. The light color-separated into G light and R light by the dichroic mirror 16 is incident on polarization beam splitters (polarization separation optical systems) 17G and 17R arranged for each color light, and polarized light arranged perpendicular to the XY plane. The light is reflected by the separation unit and enters the reflection type light valves 18G and 18R arranged for each color light.

  In this embodiment, the plane formed by the optical axes of the B light, G light, and R light separated by the cross dichroic mirror 13, the deflecting mirrors 14 and 15, and the dichroic mirror 16 constituting the color separation optical system is XY. The plane is parallel to the plane and is orthogonal to the optical axis of the light source light emitted from the light source 13.

  Each color light incident on each of the reflection type light valves 18R, 18G, 18B arranged for each color light is modulated by the color signal of each color light. The reflection type light valves 18R, 18G, and 18B again convert the modulated light converted into polarized light having a vibration direction different from that of the incident light and the non-modulated light reflected by the same polarization as the incident light, to the polarization beam splitters 17B, 17G, and 17R. Respectively. The polarization beam splitters 17B, 17G, and 17R detect and extract only the modulated light that passes through the polarization separation unit, and enter it from different incident surfaces of the cross dichroic prism 19 that constitutes the color synthesis optical system. The R light is reflected by an R light reflecting dichroic film 19R arranged perpendicular to the XY plane, and the B light is reflected by a B light reflecting dichroic film 19B arranged perpendicular to the XY plane and orthogonal to the R light reflecting dichroic film 19R. Then, the G light passes through both films, is color-combined, and is emitted from the exit surface in a direction parallel to the X axis. The combined light enters through a projection lens (projection optical system) 20 and is projected on a screen (not shown).

  The projection lens 20 includes a rear group lens 20A, a front group lens 20B, and a deflection mirror 20C disposed therebetween. The deflection mirror 20C is perpendicular to the XY plane, and the incident angle of the incident optical axis to the deflection mirror 20C is less than 45 degrees. The optical axis of the projection light emitted from the front group lens 20B of the projection lens 20 is parallel to the XY plane, and the angle θ formed by the optical axis and the optical axis of the combined light incident on the rear group lens 20A is less than 90 degrees. is there.

  FIG. 2 is a conceptual view for explaining a projection display device used in the rear projection display device according to the first embodiment of the present invention.

  A part of the housing 30 is not shown.

  A plane parallel to the paper surface (a plane parallel to the XY plane) in FIG. 1 is a plane (a plane parallel to the XY plane) perpendicular to the floor member 31A (a plane parallel to the XZ plane) in FIG. The optical member constituting the projection display device 10 is mounted on a floor member (surface) 31A of the housing 30 parallel to the XY plane. The reflective light valves 18R, 18G, and 18B for light of each color and the polarization beam splitters 17R, 17G, and 17B are coupled using an unillustrated integrated member (FIG. 2 shows only the arrangement of both). ing).

  The integrated light valves 18R, 18G, and 18B for the respective colors and the polarizing beam splitters 17R, 17G, and 17B are attached to the cross dichroic prism 19 of the color synthesis optical system using optical path length correcting optical members 21R, 21G, and 21B, respectively. It has been. One of the X-type exposed surfaces of both dichroic films 19R and 19B of the cross dichroic prism 19 in the integrated optical component (integrated optical component) is bonded to the floor surface member 31A. Further, the dichroic mirror 16, the deflection mirrors 14 and 15, and the dichroic mirrors 13B and 13RG constituting the cross dichroic mirror 13 are respectively mounted on the floor member 31A using mounting members (not shown). Furthermore, an opening 31B that ensures passage of light source light emitted from the light source 11 is formed below the cross dichroic mirror 13 of the floor member 31A.

  The lens barrel portion on the incident surface side of the projection lens 20 is attached to the mount portion 31 </ b> B of the box member 31.

  FIG. 3 is a view of the projection display device of FIG. 2 viewed from the X-axis direction.

  The housing 30 is a combination of a box member 31 and a box member 32.

  In the box member 31, an integrated optical component composed of the reflection type light valves 18R, 18G, 18B, the polarization beam splitters 17R, 17G, 17B and the cross dichroic prism 19 is attached to the floor member 31A by the method described above. . In the box member 32 arranged adjacent to the box member 31, the polarization conversion illumination device 12 and the light source 11 attached to the floor member 31A from the opposite direction to the integrated optical component are arranged.

  FIG. 4 is a conceptual diagram showing a longitudinal section of the rear projection type display device.

  The reflection mirror 42 and the screen 43 are each perpendicular to the XY plane, and both are arranged at a predetermined angle. The projection lens 20 of the projection type display device 10 is arranged close to the front member 41A to which the screen 43 is attached. The projection light emitted from the projection lens 20 is reflected by the reflection mirror 42 and a projection image is projected onto the screen 43. A portion that is the outer edge portion of the diffuse projection light emitted from the projection lens 20 and that is incident on the uppermost portion of the screen 42 can be incident on a position closest to the screen 43 of the reflection mirror 42.

  According to the projection type display apparatus of this embodiment, the optical axis of the light source light emitted from the light source 11 is orthogonal to the virtual plane formed by the optical axes of the respective color lights traveling by being separated by the color separation optical system. Therefore, the projection lens 20 can be brought close to the screen 43, and the thickness (dimension in the X-axis direction) of the rear projection display device can be reduced.

  Further, since the distance between the uppermost part of the screen 43 on which the light from the reflection mirror 42 enters and the reflection mirror 42 can be made shorter than that of the conventional example, the thickness of the rear projection display device can be further reduced.

  FIG. 5 is a diagram showing a basic configuration of a projection type display device used in a rear projection type display device according to a second embodiment of the present invention, and parts common to the first embodiment are assigned the same reference numerals and Description is omitted.

  As shown in FIG. 5, the X axis, the Y axis, and the Z axis are orthogonal to each other. The Z axis is orthogonal to the paper surface and indicates a direction from the lower part of the paper toward the upper part.

  As in the first embodiment, each of the optical axes of the B light, G light, and R light separated by the cross dichroic mirror 13, the deflection mirrors 14 and 15, and the dichroic mirror 16 constituting the color separation optical system is formed. The plane that is parallel to the XY plane. The optical axis of the light source light emitted from the light source 11 is parallel to the Z axis and perpendicular to a plane parallel to the XY plane.

  This embodiment is different from the first embodiment in that the reflection direction of the deflecting mirror 20C disposed between the rear group lens 20A and the front group lens 20B is parallel to the XZ plane of FIG. The angle formed by the optical axis of the combined light incident on the projection lens 20 and the optical axis of the projection light emitted from the projection lens 20 is less than 90 degrees, and the angle is the same as in the first embodiment. In addition, the arrangement of the reflective light valves for color light 18B, 18G, and 18G having the rectangular image forming area with respect to the polarization beam splitters 17B, 17G, and 17R is different from that of the projection display device of the first embodiment. In this embodiment, the short sides of the rectangular image forming regions of the reflection type light valves 18B, 18G, and 18R arranged in the height direction (Z-axis direction) of the polarizing beam splitters 17B, 17G, and 17R are parallel to the Z-axis. Arranged.

  FIG. 6 is a conceptual diagram for explaining a projection type display device used in a rear projection type display device according to a second embodiment of the present invention.

  The light valves 18B, 18G, and 18R, the polarizing beam splitters 17B, 17G, and 17R, and the cross dichroic prism 19 are integrated. The lower surface of the cross dichroic prism 19 is attached to a floor member 31 </ b> A parallel to the XY plane of the housing 30. The housing 30 is composed of box members 31 and 32 joined so as to be adjacent to each other. The lens barrel portion on the incident surface side of the projection lens 20 is attached to the mount portion 31 </ b> B of the box member 31. The dichroic mirror 16, the deflection mirrors 14 and 15, and the cross dichroic mirror 13 are arranged on the floor member 31A. Note that a circular opening that ensures passage of light source light is formed in the lower portion of the cross dichroic mirror 13 of the floor member 31A.

  The light source 11 and the polarization conversion illumination device 12 are arranged in the box member 32 as shown in the figure, and the light source light travels in a direction parallel to the Z axis and enters the cross dichroic mirror 13 through the opening.

  FIG. 7 is a conceptual diagram showing a longitudinal section of the rear projection type display device. The same reference numerals are given to the same parts as those in the first embodiment, and the description thereof is omitted.

  The reflection mirror 42 and the screen 43 are each perpendicular to the XY plane, and both are arranged at a predetermined angle. The projection lens 20 is arranged close to the front member 41A to which the screen 43 is attached. The projection light emitted from the projection lens 20 is reflected by the reflection mirror 42, and a projection image is projected on the screen 43. At this time, the outer edge of the diffuse projection light emitted from the projection lens 20 and entering the uppermost part of the screen 42 can be made incident at a position closest to the screen 43.

  According to this embodiment, the same effects as those of the first embodiment can be obtained.

  In the present specification, the optical axis refers to the center line of the light beam.

FIG. 1 is a diagram showing a basic configuration of a projection display device used in a rear projection display device according to a first embodiment of the present invention. FIG. 2 is a conceptual view for explaining a projection display device used in the rear projection display device according to the first embodiment of the present invention. FIG. 3 is a view of the projection display device of FIG. 2 viewed from the X-axis direction. FIG. 4 is a conceptual diagram showing a longitudinal section of the rear projection type display device. FIG. 5 is a diagram showing a basic configuration of a projection display device used in a rear projection display device according to the second embodiment of the present invention. FIG. 6 is a conceptual diagram for explaining a projection type display device used in a rear projection type display device according to a second embodiment of the present invention. FIG. 7 is a conceptual diagram showing a longitudinal section of the rear projection type display device. FIG. 8 is a conceptual diagram of a conventional projection display device. FIG. 9 is a conceptual diagram showing a longitudinal section of a conventional rear projection display device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Light source 12 Polarization conversion illumination apparatus 13, 13B, 13RG Cross dichroic mirror 14, 15 Deflection mirror 16 Dichroic mirror 17R, 17G, 17B Polarization beam splitter 18R, 18G, 18B Reflection type light valve 19 Cross dichroic prism 20 Projection lens (projection optics) system)
20C Deflection mirror 31A Floor member (surface)
42 reflection mirror 43 screen

Claims (6)

A color separation optical system for separating the light source light emitted from the light source into a plurality of color lights;
A polarization separation optical system that is arranged for each color light and separates each color light color-separated by the color separation optical system;
A projection optical system that projects light emitted from a light valve that modulates each color light emitted from the polarization separation optical system onto a reflection mirror;
In a rear projection type display device comprising a screen on which the projection light reflected by the reflection mirror is incident,
The rear projection display device, wherein an optical axis of the light source light incident on the color separation optical system is perpendicular to a plane including each color light color-separated by the color separation optical system. The projection optical system is
A projection lens;
The rear projection display device according to claim 1, further comprising: a deflecting mirror that deflects light incident on the projection lens. The rear projection type display device according to claim 1, wherein the projection optical system is disposed in the vicinity of the screen.   The angle formed by the optical axis of the light incident on the projection optical system and the optical axis of the projection light emitted from the projection optical system is less than 90 degrees. The rear projection type display device described.   5. The optical axis of projection light emitted from the projection optical system is parallel to a plane perpendicular to the polarization separation unit of the polarization separation optical system. Rear projection type display device.   5. The optical axis of projection light emitted from the projection lens is inclined with respect to a plane perpendicular to the polarization separation portion of the polarization separation optical system. Rear projection type display device.

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