JP2007003809A - Projection image display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make the size of an optical system from a light source to reflection type spatial optical modulation elements smaller and to make the size of an apparatus configuration smaller in a projection image display apparatus using the reflection type spatial optical modulation elements and reflection type polarizing plates. <P>SOLUTION: The apparatus is equipped with the reflection type polarizing plates 7, 12, 15 for respective color light rays which make one polarized light component of the respective color light rays R, G, B subjected to color separation by color separation optical systems 4, 10 incident on the reflection type spatial optical modulation elements 8, 13, 16 for the respective colors and reflect the image light rays reflected by the reflection type spatial optical modulation elements 8, 13, 16, a color composition optical system 17 which performs color composition of the image light rays reflected by the respective reflection type polarizing plates 7, 12, 15, and a projection lens 18 which projects the image light rays subjected to the color composition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a projection type image display apparatus that displays an image by forming an image modulated using a spatial light modulation element such as a liquid crystal light valve by a projection lens.

  2. Description of the Related Art Conventionally, projection type image display devices using spatial light modulation elements such as liquid crystal light valves can display images with high resolution and high contrast ratio, and therefore various types of devices have been developed and commercialized. .

  Many of such projection-type image display apparatuses are so-called “color projectors” configured to include three spatial light modulation elements. This "color projector" separates white light obtained from a powerful light source such as a metal halide lamp into three primary color lights, and guides each color light thus separated to a spatial light modulation element corresponding to each color. Modulation is performed by driving the modulation element with an image signal corresponding to each color, and image display is performed by combining and projecting modulated light of each color.

  As a projection type image display apparatus using a reflective spatial light modulation element, for example, as described in Patent Document 1, image light modulated by a spatial light modulation element is separated by a reflective polarizing plate. What has been proposed.

  In the projection type image display apparatus using such a reflective polarizing plate, as shown in FIG. 6, the illumination light emitted from the light source 101 passes through the light pipe 102 constituting the illumination optical system, and the first In the dichroic mirror 103, blue (B) light is transmitted and red-green (RG) light is reflected, whereby color separation is performed.

  The blue (B) light 104 transmitted through the first dichroic mirror 103 is reflected by the mirrors 105 and 106 and is incident on the first reflective polarizing plate 107, and only the light in one polarization direction is the first light. The light passes through the reflective polarizing plate 107. The blue (B) light transmitted through the first reflective polarizing plate 107 enters the first reflective spatial light modulation element 108 corresponding to the blue (B) light.

  Further, red-green (RG) light 109 reflected by the first dichroic mirror 103 is reflected by the mirror 110 and enters the second dichroic mirror 111. In the second dichroic mirror 111, red (R) light is transmitted and green (G) light is reflected, so that the red (R) light and green (G) light are color-separated.

  The red (R) light that has passed through the second dichroic mirror 111 is incident on the second reflective polarizing plate 113, and only light in one polarization direction passes through the second reflective polarizing plate 113. The red (R) light transmitted through the second reflective polarizing plate 113 enters the second reflective spatial light modulator 115 corresponding to the red (R) light.

  Then, the green (G) light reflected by the second dichroic mirror 111 is incident on the third reflective polarizing plate 112, and only light in one direction of polarization passes through the third reflective polarizing plate 112. To Penetrate. The green (G) light transmitted through the third reflective polarizing plate 112 is incident on the third reflective spatial light modulation element 114 corresponding to the green (G) light.

  The red (R) light, green (G) light, and blue (B) light incident on each of the reflective spatial light modulators 108, 115, and 114 includes image light that is polarization-modulated according to the respective image signals. Reflected. The image light is reflected by the reflective polarizing plates 107, 113, and 112, and is incident on the cross dichroic prism 116 from three directions.

  The cross dichroic prism 116 combines red (R) light, green (G) light, and blue (B) light and enters the projection lens 117. The projection lens 117 forms an image by forming each incident image light on a screen (not shown).

JP 2004-279705 A

  By the way, in the above-described conventional projection type image display apparatus, since each color light after color separation by the dichroic mirrors 103 and 111 is frequently deflected by the mirror, the apparatus configuration becomes larger and complicated. There is a problem of end. That is, in this projection type image display apparatus, the blue (B) light color-separated by the first dichroic mirror 103 is deflected twice by the mirrors 105 and 106.

  Therefore, the present invention has been proposed in view of the above circumstances, and in a projection-type image display apparatus using a reflective spatial light modulation element and a reflective polarizing plate, an optical element from a light source to the spatial light modulation element is proposed. It is an object of the present invention to provide a projection type image display apparatus in which the size of the apparatus is reduced by downsizing the system.

  In order to solve the above-described problems, a projection-type image display device according to the present invention has one of the following configurations.

[Configuration 1]
A light source, a color separation optical system that separates light from the light source into three primary colors of red light, green light, and blue light, and a reflective space for each color light corresponding to the three primary colors of red light, green light, and blue light Reflective spatial light modulation element for each color light by transmitting a light polarization element and a P-polarized light component or a S-polarized light polarized light component for each color of red light, green light and blue light that has passed through a color separation optical system And a reflection type polarizing plate for each color light that reflects the image light of each color that has been polarized and modulated in accordance with the image signal of each corresponding color light in each reflection type spatial light modulator, and each of these reflections The image forming apparatus includes a color combining optical system that combines the image light reflected by the mold polarizing plate and a projection lens that projects the color combining image light obtained by the color combining optical system.

[Configuration 2]
In the projection-type image display apparatus having the configuration 1, the reflection-type polarizing plate transmits the P-polarized polarization component and reflects the S-polarization polarization component among the incident color lights. .

  In this projection type image display device, the number of times the optical path is deflected by the mirror before the red light, green light and blue light that have passed through the color separation optical system enter the corresponding reflective spatial light modulator. By making it once or less, it is possible to reduce the size of the optical system from the light source to the spatial light modulator.

  An illumination optical system that makes the intensity distribution of light emitted from the light source uniform may be disposed between the light source and the color separation optical system.

  In this projection type image display apparatus, as a color separation optical system, red-green (RG) light and blue (B) light are color-separated by a cross dichroic mirror in which two dichroic mirrors are formed in a cross shape. Or a first color separation optical system that separates red (R) light and green-blue (GB) light, and red-green (RG) light or green-blue (GB) light into red (R) It may be composed of a second color separation optical system that performs color separation into light and green (G) light, or color separation into green (G) light and blue (B) light.

  Further, after the reflection type polarizing plate, a transmission type polarizing plate for each color light that removes an unnecessary polarization component from the image light of each color reflected by the reflection type polarizing plate for each color light may be installed.

  As the color synthesis optical system, a cross dichroic prism or a so-called Philips prism can be used.

  In addition, each reflective polarizing plate can prevent the occurrence of coma aberration in the reflective polarizing plate by setting the reflective element surface that reflects image light toward the reflective spatial light modulator side. it can.

  In the projection type image display apparatus according to the present invention, the number of times the optical path is deflected by the mirror before the red light, the green light, and the blue light that have passed through the color separation optical system enter the corresponding reflective spatial light modulator. By making the number of times one or less, the optical system from the light source to the spatial light modulator can be miniaturized.

  That is, according to the present invention, in a projection-type image display device using a reflective spatial light modulator and a reflective polarizing plate, the optical system from the light source to the spatial light modulator is miniaturized, thereby reducing the size of the device configuration. It is possible to provide a projection type image display apparatus in which

  Embodiments of a projection-type image display device according to the present invention will be described in detail below with reference to the drawings.

[First Embodiment]
FIG. 1 is a plan view showing the configuration of the projection type image display apparatus according to the first embodiment of the present invention.

  In this projection type image display device, as shown in FIG. 1, the illumination light emitted from the light source 1 passes through the light pipe (rod integrator) 2 constituting the illumination optical system, passes through the condenser lens 3, and the first Is incident on a cross dichroic mirror 4 serving as a color separation optical system. In addition, as the light source 1, what can obtain strong white light, such as a metal halide lamp, is used. In the light pipe 2, the illumination light from the light source 1 is internally reflected many times, so that the illuminance distribution of the illumination light is made uniform.

  The cross dichroic mirror 4 is configured by combining two dichroic mirrors in a cross shape. One dichroic mirror reflects blue light B, and the other dichroic mirror reflects red-green light RG. have. In the cross dichroic mirror 4, the illumination light from the light source 1 reflects the blue light B component in one direction, and the red-green light RG component in the other direction opposite to the direction in which the blue light B component is reflected. Reflected.

  The blue light B reflected in one direction by the cross dichroic mirror 4 is reflected and deflected by the first mirror 5, and enters the first reflective polarizing plate 7 through the relay lens 6. The first reflective polarizing plate 7 is a so-called “wire grid” and is inclined at about 45 ° with respect to the optical path, and only the P deflection component with respect to the first reflective polarizing plate 7 is provided. Make it transparent. The blue light B transmitted through the first reflective polarizing plate 7 enters the first reflective spatial light modulator 8 corresponding to the blue light B. This reflective spatial light modulator is, for example, a reflective liquid crystal light valve. Further, the red-green light RG reflected in the other direction by the cross dichroic mirror 4 is reflected and deflected by the second mirror 9 and enters the dichroic mirror 10 serving as the second color separation optical system. In the dichroic mirror 10, the red light R is transmitted and the green light G is reflected, whereby the red light R and the green light G are color-separated.

  The red light R that has passed through the dichroic mirror 10 enters the second reflective polarizing plate 12 via the relay lens 11. The second reflective polarizing plate 12 is a so-called “wire grid” and is inclined at about 45 ° with respect to the optical path, and only the P deflection component with respect to the second reflective polarizing plate 12 is provided. Make it transparent. The red light R transmitted through the second reflective polarizing plate 12 enters the second reflective spatial light modulation element 13 corresponding to the red light R.

  The green light G reflected by the dichroic mirror 10 enters the third reflective polarizing plate 15 via the relay lens 14. The third reflective polarizing plate 15 is a so-called “wire grid”, and is inclined at about 45 ° with respect to the optical path, and only the P deflection component with respect to the third reflective polarizing plate 15 is provided. Make it transparent. The green light G transmitted through the third reflective polarizing plate 15 enters the third reflective spatial light modulation element 16 corresponding to the green light G.

  FIG. 2 is a perspective view showing the configuration of the reflective polarizing plate.

  As shown in FIG. 2, each of the reflective polarizing plates 7, 12, and 15 is formed by arranging a large number of metal wires 202 such as aluminum regularly in a stripe pattern at a pitch of about 140 nm on the optical glass plate 201. It has a reflective element surface. The reflective polarizing plates 7, 12, and 15 transmit a polarization component perpendicular to the metal line 202 (for example, P-polarized light) as it is and transmit a polarization component parallel to the metal line 202 (for example, S-polarized light). It has the property of reflecting.

  In the reflection type polarizing plates 7, 12, and 15, even if the incident angle varies, the variation in wavelength dependency of the transmittance of the P-polarized light is extremely small, and stable characteristics are maintained. Therefore, in this projection type image display apparatus, a bright display image with good color reproducibility can be obtained by using the reflective polarizing plates 7, 12, and 15. Further, the reflection type polarizing plates 7, 12, and 15 are a single plate-like polarization separation plate, and thus are lightweight. Further, since the reflective polarizing plates 7, 12, and 15 hardly absorb the light emitted from the light source 1, it is possible to suppress the deterioration of the display image quality due to birefringence.

  The reflective polarizing plates 7, 12, and 15 have reflective element surfaces that reflect image light from the reflective spatial light modulators 8, 13, and 16, and the reflective spatial light modulators 8, 13, and 16. Install it facing the side. By installing in this way, coma aberration in the optical glass plate 201 of the reflective polarizing plates 7, 12, and 15 for image light from each of the reflective spatial light modulators 8, 13, 16 to the projection lens 18 described later. Occurrence can be prevented.

  The blue light B, red light R, and green light G incident on the reflective spatial light modulators 8, 13, 16 are subjected to S deflection with respect to the reflective polarizers 7, 12, 15 according to the respective image signals. Reflected image light including polarization-modulated image light. As shown in FIG. 1, these image lights are respectively reflected by the reflection type polarizing plates 7, 12, and 15, and are incident on the cross dichroic prism 17 serving as a color synthesis optical system from three directions.

  An unnecessary polarization component is removed from the image light of each color reflected by the reflective polarizers 7, 12, and 15 for each color light between the respective reflective polarizers 7, 12, and 15 and the cross dichroic prism 17. In order to do so, a transmissive polarizing plate for each color light may be provided.

  This cross dichroic prism 17 is a prism formed by joining four triangular prisms into a cubic shape, and a dichroic film is formed on the joint surface of each triangular prism. The dichroic film is formed in a state where two planes intersect in a cross shape at the center of the cross dichroic prism 17. The dichroic film forming one plane in the cross dichroic prism 17 reflects the blue light B component and transmits the red light R and green light G components. The dichroic film forming the other plane in the cross dichroic prism 17 reflects the red light R component and transmits the blue light B and green light G components.

  Accordingly, in the cross dichroic prism 17, the blue light B incident from one side surface is reflected by the dichroic film forming one plane and emitted forward, and the red light R incident from the other side surface passes through the other plane. The blue light B, red light R, and green light G are synthesized by the green light G that is reflected by the dichroic film formed and emitted forward, and is emitted from the rear surface through each dichroic film and emitted forward. Is done.

  The blue light B, red light R, and green light G synthesized in the cross dichroic prism 17 in this way are incident on the projection lens 18. The projection lens 18 forms an image by forming each incident image light on a screen (not shown).

[Second Embodiment]
FIG. 3 is a plan view showing the configuration of the projection type image display apparatus according to the second embodiment of the present invention.

  In the projection type image display apparatus according to the present invention, as shown in FIG. 3, a fly eye integrator 20 may be used as the illumination optical system instead of the light pipe 2 described above.

  That is, in this projection type image display apparatus, the illumination light emitted from the light source 1 passes through the fly eye integrator 20 constituting the illumination optical system, passes through the condenser lens 3, and becomes the first color separation optical system. The light enters the cross dichroic mirror 4. The subsequent configuration is the same as that of the first embodiment.

  The fly eye integrator 20 has a small-diameter convex lens formed in a matrix on each of a pair of flat transparent substrates. In the fly eye integrator 20, a large number of light source images are formed, and these light source images are superimposed to make the illuminance distribution of the illumination light uniform.

[Third Embodiment]
FIG. 4 is a plan view showing the configuration of the projection type image display apparatus according to the third embodiment of the present invention.

  As shown in FIG. 4, the projection type image display apparatus according to the present invention may use a so-called Philips prism 21 as a color synthesis optical system.

  That is, in this projection type image display device, the optical path from the color separation optical system until the illumination light enters each of the spatial light modulation elements 8, 13, 16 is the same as that in the first embodiment. . However, in this projection type image display device, the first and second reflective polarizing plates 7 and 12 are installed with an inclination of about 30 ° with respect to the optical path.

  The blue light B, red light R, and green light G incident on the reflective spatial light modulators 8, 13, 16 are subjected to S deflection with respect to the reflective polarizers 7, 12, 15 according to the respective image signals. Reflected image light including polarization-modulated image light. These image lights are respectively reflected by the reflective polarizing plates 7, 12, and 15 and are incident on the Philips prism 21 serving as a color synthesis optical system from three directions.

  The Philips prism 21 combines the blue light B, red light R, and green light G and enters the projection lens 18. The projection lens 18 forms an image by forming each incident image light on a screen (not shown).

  The Philips prism 21 is, for example, a prism that does not have a joint at the screen corresponding portion as described in Japanese Patent No. 2505758, and is used as a color separation prism in a so-called “three-plate video camera”. Is. The Phillips prism 21 is composed of at least first to third prisms 21a, 21b, and 21c arranged to form at least two pairs of opposing surfaces, and the first prism 21a and the second prism 21b are joined. A first dichroic film that reflects red light R and transmits green light G is formed on the first facing surface, and the second facing surface that joins the first prism 21a and the third prism 21c is formed on the first facing surface. A second dichroic film that transmits red light R and green light G and reflects blue light B is formed.

  Therefore, in this Philips prism 21, the red light R incident from the first prism 21a is reflected by the first dichroic film, passes through the second dichroic film, enters the third prism 21c, and The green light G incident from the second prism 21b passes through the first and second dichroic films as they are, enters the third prism 21c, and the blue light B incident from the third prism 21c Reflected by the two dichroic film, the image light of the red light R, the green light G, and the blue light B is color-synthesized in the third prism 21c.

[Fourth Embodiment]
FIG. 5 is a plan view showing a configuration of the projection type image display apparatus according to the fourth embodiment of the present invention.

  The projection type image display apparatus according to the present invention can be configured without using a cross dichroic mirror as shown in FIG.

  That is, in this projection type image display apparatus, as shown in FIG. 5, the illumination light emitted from the light source 1 passes through the light pipe (rod integrator) 2 constituting the illumination optical system, and passes through the condenser lens 3. Then, the light enters the first dichroic mirror 22 serving as a first color separation optical system. The first dichroic mirror 22 has a characteristic of transmitting the blue light B and reflecting the red-green light RG. That is, in the first dichroic mirror 22, the illumination light from the light source 1 transmits the blue light B component and reflects the red-green light RG component.

  The blue light B that has passed through the first dichroic mirror 22 is incident on the first reflective polarizing plate 7 via the relay lens 6. The first reflective polarizing plate 7 is installed with an inclination of about 45 ° with respect to the optical path, and transmits only the P deflection component with respect to the first reflective polarizing plate 7. The blue light B transmitted through the first reflective polarizing plate 7 enters the first reflective spatial light modulator 8 corresponding to the blue light B.

  Further, the red-green light RG reflected by the first dichroic mirror 22 is reflected and deflected by the mirror 9 and enters the second dichroic mirror 10 serving as a second color separation optical system. In the second dichroic mirror 10, the red light R is transmitted and the green light G is reflected, so that the red light R and the green light G are color-separated.

  The red light R transmitted through the second dichroic mirror 10 enters the second reflective polarizing plate 12 through the relay lens 11. The second reflective polarizing plate 12 is installed with an inclination of about 45 ° with respect to the optical path, and transmits only the P deflection component with respect to the second reflective polarizing plate 12. The red light R transmitted through the second reflective polarizing plate 12 enters the second reflective spatial light modulation element 13 corresponding to the red light R.

  Further, the green light G reflected by the second dichroic mirror 10 enters the third reflective polarizing plate 15 via the relay lens 14. The third reflective polarizing plate 15 is installed with an inclination of approximately 45 ° with respect to the optical path, and transmits only the P deflection component with respect to the third reflective polarizing plate 15. The green light G transmitted through the third reflective polarizing plate 15 enters the third reflective spatial light modulation element 16 corresponding to the green light G.

  The blue light B, red light R, and green light G incident on the reflective spatial light modulators 8, 13, 16 are subjected to S deflection with respect to the reflective polarizers 7, 12, 15 according to the respective image signals. Reflected image light including polarization-modulated image light. These image lights are respectively reflected by the reflective polarizing plates 7, 12, and 15 and are incident on the cross dichroic prism 17 serving as a color synthesis optical system from three directions.

  The cross dichroic prism 17 combines the blue light B, the red light R, and the green light G and enters the projection lens 18. The projection lens 18 forms an image by forming each incident image light on a screen (not shown).

It is a top view which shows the structure in 1st Embodiment of the projection type image display apparatus which concerns on this invention. It is a perspective view which shows the structure of the reflection type polarizing plate in the said projection type image display apparatus. It is a top view which shows the structure in 2nd Embodiment of the projection type image display apparatus which concerns on this invention. It is a top view which shows the structure in 3rd Embodiment of the projection type image display apparatus which concerns on this invention. It is a top view which shows the structure in 4th Embodiment of the projection type image display apparatus which concerns on this invention. It is a top view which shows the structure of the conventional projection type image display apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 4 Cross dichroic mirror 7 1st reflection type polarizing plate 8 1st reflection type spatial light modulation element 10 Dichroic mirror (2nd dichroic mirror)
12 Second Reflective Polarizing Plate 13 Second Reflective Spatial Light Modulator 15 Third Reflective Polarizer 16 Third Reflective Spatial Light Modulator 17 Cross Dichroic Prism 18 Projection Lens 21 Phillips Prism 22 First Dichroic mirror R Red light G Green light B Blue light

Claims (2)

A light source;
A color separation optical system that separates light from the light source into three primary colors of red light, green light, and blue light;
A reflective spatial light modulator for each color light corresponding to the three primary colors of red light, green light and blue light;
Each of the red light, green light, and blue light that has passed through the color separation optical system transmits a P-polarized light component or a S-polarized light polarized component, and the corresponding reflective spatial light modulator for each color light respectively. A reflective polarizing plate for each color light that is incident and reflects image light of each color that is polarized and modulated according to an image signal of each corresponding color light in each of the reflective spatial light modulators;
A color synthesizing optical system that color-synthesizes the image light reflected by each of the reflective polarizing plates;
A projection type image display apparatus comprising: a projection lens that projects the color synthesis image light obtained by the color synthesis optical system. 2. The projection type image display device according to claim 1, wherein the reflection-type polarizing plate transmits a P-polarized polarization component and reflects an S-polarization polarization component among incident color lights.

Images