JPH1164796A - Projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize the whole of a projection type display device obtained by hierarchically constituting a modulation, color synthesizing and projection optical system, a polarized light selection optical system and a color resolving and light guiding optical system by resolving color by two independent dichroic mirrors and constituting the light guiding optical system to be compact. SOLUTION: The color resolving and light guiding optical system is constituted of two dichroic mirrors 6 and 8, reflection mirrors 7G, 10 and 10' and correction lenses 9 and 9'. Then, a square area 31 for demarcating an area occupied by the respective optical elements in terms of a plane surface is made to fall in a square area for demarcating an area occupied by the modulation, color synthesizing and projection optical system in terms of the plane surface. The optical path length of red light (r) bypassed under a projection lens 16 becomes longer than those of blue light (b) and green light (g). However, since a sufficient space is secured in a bypassed optical path, the lenses 9 and 9' are made to intervene in the bypass optical path so as to make the optical path length of three primary colors substantially equal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type display device, and is applied to a three-plate color projector or the like using a reflection type spatial light modulator. The present invention relates to an improvement for preventing deterioration and an arrangement of optical elements for miniaturizing the apparatus.

[0002]

2. Description of the Related Art In a three-plate type color projector, white light obtained from a powerful light source such as a metal halide lamp is converted into three light beams.
Adopts a method of decomposing into primary colors, guiding each color-separated light to a spatial light modulator such as a liquid crystal panel driven by a video signal related to each corresponding color, modulating, combining each modulated light and projecting. doing. And in the color separation / light guide optical system of the device,
In general, in order to obtain a high-brightness projection image and to suppress the occurrence of color shading, it is common to design the light path length from the light source to the spatial light modulator of each corresponding color to be equal.

For example, in a projection display device using a reflection type spatial light modulator, a cross type dichroic mirror in which the reflection surfaces of two dichroic mirrors cross each other in an X-shape is used as color separation means. A device in which the color separation / light guiding optical system is symmetrical with respect to the three primary colors so that the optical path length from the light source to each spatial light modulator is equal (Japanese Patent Application No. 9-10065).
Also, in a projection display device using a transmissive spatial light modulator, two independent dichroic mirrors are used as color separation means, and the optical paths of the three primary colors are configured asymmetrically, but the optical path length increases. A device in which a correction lens for correcting the light quantity loss is provided in the optical path of the color of light, and the optical path length from the light source to each spatial light modulator is made substantially equal (International Publication Number: WO94 / 2
2042) has been proposed.

As an example of applying the color separation / light guide optical system of the apparatus according to the international application to an apparatus using a reflection type spatial light modulator, a projection type optical system as shown in FIGS. A display device is conceivable. As shown in FIG. 7, the optical structure of the device is roughly divided into a lower layer color separation / light guide optical system, an intermediate layer polarization selection optical system, and an upper layer modulation / color synthesis / projection optical system. 8 to 10 show plan views of those optical systems as viewed from below.

In each of the figures, 1 is a light source, 2 is a collimator lens, 3 is a first integrator, 4 is a second integrator, 5 is a cold mirror, 17 is white light, which is cyan light (mixed color light of green light and blue light). : gb) and a dichroic mirror that separates red light r, 18 is a dichroic mirror that separates cyan light into green light g and blue light b, 19B, 19B ', 19R, 20G, 20B and 20R are reflection mirrors and 9, 9' Is a correction lens for correcting light loss, 11G,
11B and 11R are condenser lenses, 12G, 12B and 12R are first polarizing beam splitters, 13G, 13B and 13R are second polarizing beam splitters, and 14G, 14B and 14R are reflection type spatial light modulation using liquid crystal. Section, 15 is a crossed dichroic prism for color synthesis, 16
Is a projection lens. 8 to 10, the reflecting mirrors 20G, 20B, 20R, the condensing lens and the first polarizing beam splitter units 11G, 12G, 11B, 12B, 11R, 12
R, and the second polarization beam splitter and the unit 13G / 14G, 13B / 14B, 13R / 14R of the spatial light modulator are attached as side views as viewed from the direction of the arrow indicated by the two-dot chain line, respectively. The optical functions within each level are also shown.

First, in a color separation / light guide optical system, white light w emitted from a light source 1 which is an elliptical reflecting mirror is once focused on a second focal point of the reflecting mirror, and then converted into a parallel light by a collimator lens 2. Then, the first integrator 3 at the next stage is irradiated. Here, the first integrator 3 and the second integrator 4 are each formed by arranging minute lenses (lens segments) vertically and horizontally.
The light beam transmitted through each lens segment of the second integrator 4 is focused on the corresponding lens segment of the second integrator 4,
The luminance distribution of the light source image is averaged by the integrator 4, and as a result, readout light having a uniform illuminance distribution for each of the spatial light modulators 14G, 14B, and 14R can be obtained.
Further, the white light w transmitted through the second integrator 4 is reflected by the cold mirror 5, and at that time, unnecessary infrared light contained in the white light w is removed.

Next, the white light w reflected by the cold mirror 5 and changed in direction by 90 ° in the horizontal plane enters the dichroic mirror 17, and the dichroic mirror 17 is turned by 90 ° in the horizontal plane by its wavelength-selective reflection film. The reflected light is separated into the reflected cyan light gb and the transmitted red light r. The cyan light gb reflected by the dichroic mirror 17 is incident on the next dichroic mirror 18, and is separated into reflected green light g and transmitted light blue light b, which have been converted in the horizontal plane by 90 °. Therefore, the white light w
Is separated into three primary color lights by two dichroic mirrors 17 and 18.

The green light g reflected by the dichroic mirror 18 is directly incident on the reflecting mirror 20G, and its optical path is vertically changed by 90 °. The red light r transmitted through the dichroic mirror 17 is reflected by a reflecting mirror 19R in a horizontal plane. At 9
After the direction is changed by 0 °, it is 9 in the vertical direction by the reflection mirror 20R.
The light is changed in the direction of 0 ° and enters the condenser lenses 11G and 11R disposed immediately above the reflection mirrors 20G and 20R, respectively. On the other hand, the blue light b transmitted through the dichroic mirror 18 is condensed by two correction lenses 9 and 9 ′ and is corrected by two reflection mirrors 19B and 19B.
In response to the 90 ° directional change in the horizontal plane by 19B ′, the light enters the reflecting mirror 20B in a mode in which the optical path is detoured to the side, and is turned 90 ° in the vertical direction by the reflecting mirror 20B and disposed immediately above. The light enters the condenser lens 11B.

Next, each of the units 11G and 11G comprising the condenser lens and the first polarization beam splitter in the polarization selection optical system.
As shown in FIG. 9, the three units 12G, 11B, 12B, 11R, and 12R are arranged symmetrically with respect to the projection direction so that the three units are in contact with the corners. The primary color lights g, b, and r incident on the optical lenses 11G, 11B, and 11R are converted into parallel lights, respectively.
To the polarization beam splitters 12G, 12B, and 12R. Each of the polarizing beam splitters 12G, 12B, and 12R is a polarizing film 12g, 12b, in which a large number of two types of films having different refractive indexes are alternately stacked.
12r, P in each primary color light g, b, r
Only the polarization components g (p), b (p), and r (p) are transmitted, and the S polarization components g (s), b (s), and r (s) are reflected toward the outside of the arrangement region. That is, P of each primary color light g, b, r separated at this stage
The polarization components g (p), b (p), and r (p) are selected as use light,
The S polarized light components g (s), b (s), and r (s) are discarded outside the system. Therefore, the second polarization beam splitters 13G, 13B, 13B, 13P, 13G, 13B, and 13 (P) have the P polarization components g (p), b (p), r (p) selected by the respective polarization beam splitters 12G, 12B, 12R. 13R
Will be incident.

Next, as shown in FIG. 10, units 13G and 14G, 13B and 14B, each comprising a second polarizing beam splitter and a spatial light modulator in the modulation / color combining / projection optical system.
13R and 14R are also arranged symmetrically with respect to the projection direction so as to face the incident surface of the cross-type dichroic mirror 15. Then, the first polarization beam splitters 12G, 12G
B, 12R, this second polarization beam splitter 13G, 1
The polarizing films 13B and 13R also transmit only the P-polarized light components g (p), b (p) and r (p) and reflect the S-polarized light components g (s), b (s) and r (s).
g, 13b, and 13r, and the polarizing films 13g, 13b, and 13r have tilt directions in relation to the corresponding first polarizing beam splitters 12G, 12B, and 12R and the respective polarizing films 12g, 12b, and 12r. Have a 90 ° twist relationship, the second polarization beam splitter 13
Each of the P-polarized light components g (p), b (p), and r (p) incident on G, 13B, and 13R becomes the vibration direction of the S-polarized light component with respect to the polarizing films 13g, 13b, and 13r. Accordingly, the polarized light component is reflected by the polarizing films 13g, 13b, 13r of the second polarizing beam splitters 13G, 13B, 13R, is converted by 90 ° from the vertical direction to the horizontal direction, and is converted to the corresponding spatial light modulator 14G, Light enters 14B and 14R. Each of the spatial light modulators 14G, 14B, and 14R modulates and reflects an incident polarization component by controlling the alignment state of the liquid crystal layer on a pixel basis based on video signals related to the three primary colors. Since the light changes to a polarization component in the vibration direction opposite to the incident light according to the degree of modulation, the modulated light g ′ (p), b ′ (p),
r ′ (p) enters the polarizing films 13g, 13b, 13r. Here, since the polarizing films 13g, 13b, and 13r reflect only the S-polarized component and transmit the P-polarized component as described above, the re-entered modulated light g ′ (p), b ′ (p), r ′ (p) passes through the polarizing films 13g, 13b, and 13r and enters the crossed dichroic prism 15 for color synthesis. On the other hand, though not shown, the polarization films g ′ (s), b ′ (s), and r ′ (s) for the unmodulated components are polarized films 13g, 13b, and 13 ′.
After being reflected by r, the light travels backward in the optical path and returns to the light source 1. The cross type dichroic prism 15 has a configuration in which a dichroic mirror surface 15b that reflects only blue light b and a dichroic mirror surface 15r that reflects only red light r are crossed, and the second polarization beam splitter 13B, The modulated light b ′ (p) and r ′ (p) incident from 13R are respectively converted in the horizontal direction by 90 °, and the modulated light g ′ (p) incident from the second polarizing beam splitter 13G is transmitted as it is. Therefore, the modulated lights of the three primary colors are combined and incident on the projection lens 16, and the color image enlarged by the projection lens 16 is displayed on a screen (not shown).

[0011]

By the way, Japanese Patent Application Laid-Open No. H10-157, in which color separation is performed by using the above-mentioned cross type dichroic mirror.
In the case of the projection display device of No. 9-10065, the problem of color shading does not occur because the optical path lengths for the three primary colors can be configured to be equal, but the cross type dichroic mirror has two wavelength-selective reflection films. Since it is configured in such a manner that the glass plates are crossed, the incident light is multiply reflected in the glass near the crossing portion and is not output to the outside, and a dark shadow is generated near the center in the projected image. Further, since each spatial light modulator is of a reflection type, a non-modulated polarized light component corresponding to the degree of modulation is returned and enters the crossed dichroic mirror as return light. In such a case, there is a tendency for the light to pass through the crossed dichroic mirror or to be internally reflected multiple times and to enter the spatial light modulator of another color. It causes deterioration.

On the other hand, in the projection type display device shown in FIGS. 7 to 10, since the two independent dichroic mirrors 17 and 18 are used for the color separation means, the above-mentioned problem does not occur. As shown in FIG. 8, since the color separation / light guide optical system is configured outside the planar development region of the polarization selection optical system and the modulation / color synthesis / projection optical system, a large optical system is provided on both sides and behind. There is a problem that a configuration space is required, and the size of the device cannot be reduced. That is, the polarization selection optical system and the modulation / color combining optical system are relatively compact because the units are arranged symmetrically with respect to the cross-type dichroic prism 15, but are relatively compact.
The spatial volume occupied by the entire device increases due to the expansion of the planar deployment area of the light guide optical system, and the entire housing must necessarily be designed large.

Accordingly, the present invention provides a color separation means in a three-panel projection display device using a reflection type spatial light modulator, in which two independent dichroic mirrors are applied without using a crossed dichroic mirror. It has been created for the purpose of providing an optical configuration that can be configured and that can reduce the size of the entire device.

[0014]

According to the present invention, a projection lens is arranged on an exit surface of a cross-type dichroic prism in which wavelength-selective reflection films for two different colors out of three primary colors are crossed, and three planes of incidence are provided. The polarization beam splitters are arranged in such a manner that the emission surfaces are opposed to the surfaces, respectively, and reflection-type spatial light modulation is provided on the surface of each polarization beam splitter on the side opposite to the cross-type dichroic prism and on the opposite side. And a modulation / color synthesis / projection optical system arranged with the sections facing each other, and the white light generated by the light source is decomposed into three primary color lights to enter the entrance surfaces of the respective polarization beam splitters of the modulation / color synthesis / projection optical system. In a projection type display device in which a guiding color separation / light guiding optical system is configured for each layer, each of the polarization beam splitters of the modulation / color combining / projection optical system is provided with the color separation / light guiding optical system. The direction of the polarizing film is set and arranged so as to be on the hierarchical side of the scientific system, while the color separation / light guide optical system is composed of two independent dichroic mirrors and a plurality of reflection mirrors, These mirrors are used for the modulation, color synthesis,
The three primary color lights obtained by dissolving the white light of the light source are arranged so as to substantially fit in a planar area corresponding to a rectangular area that defines the area occupied by the projection optical system. The present invention relates to a projection display device characterized in that light is guided to an incident surface of a splitter.

According to the present invention, the color separation / light guide optical system performs color separation by two independent dichroic mirrors as in the projection type display device (FIGS. 7 to 10) described in the prior art. There is no problem when using the dichroic mirror. On the other hand, if two independent dichroic mirrors are used, a symmetrical light guide system cannot be formed as in the case of using a crossed dichroic mirror, and the optical path of at least one of the three primary color lights is reduced. It is necessary to guide the light to the corresponding polarization beam splitter of the modulation / color synthesis / projection optical system in a routing manner. As a result, as shown in FIG. 8, the plane area in the hierarchical direction occupied by the color separation / light guide optical system becomes large. . According to the present invention, each of the polarization beam splitters of the modulation, color synthesis, and projection optical systems is provided with a color separation /
Arranged on the layer side of the light guide optical system, a rectangle that defines the area occupied by the modulation, color synthesis, and projection optical systems when viewing the light path routing by the color separation / light guide optical system in a plane. While being performed in the region, the corresponding primary color light can be made incident on the incident surface of each of the polarization beam splitters by a dichroic mirror or a reflection mirror. Therefore, a rectangular area that defines the area occupied by the color separation / light guide optical system in a plane can be configured to be substantially the same as that of the modulation / color synthesis / projection optical system, and the device can be downsized.

By the way, as is apparent from FIG. 7 showing the hierarchical structure of the projection type display device of the prior art, the projection lens 16 of the modulation / color synthesis / projection optical system projects forward, and A large space is configured. Therefore, in the color separation / light guide optical system of the present invention, one of the three primary color lights is used.
If the primary color light is routed in such a manner as to bypass the space and is guided to the corresponding polarizing beam splitter, a large physical space can be secured in the bypass optical path, and a correction lens can be easily interposed in the bypass optical path. .

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the projection display apparatus of the present invention will be described below in detail with reference to FIGS. FIGS. 1 to 3 show perspective views of the arrangement of each optical element of the apparatus with the viewpoint set to diagonally upward, diagonally laterally and diagonally downward, respectively. FIG. 4 shows a light source unit and color separation.・
5 is a plan view of the hierarchy of the light guide optical system as viewed from below, FIG. 5 is a plan view of the polarization selection optical system as viewed from below, and FIG. 6 is a plan view of the modulation, color synthesis, and projection optical system as viewed from below. It is. 4 to 6, as in FIGS. 8 to 10, side views of each optical element which is difficult to understand in a plan view as viewed from the direction of an arrow indicated by a two-dot chain line are attached as reference figures. Yes, the optical functions within each layer are also shown.

This device, like the projection display device shown in the prior art, has a lower layer color separation / light guide optical system, an intermediate layer polarization selection optical system, and an upper layer modulation / color synthesis / projection. It is composed of an optical system. In each drawing, the optical elements indicated by the same reference numerals as those shown in FIGS. 7 to 10 are the same, and the description thereof is omitted here. As is clear from comparison between FIGS. 5 and 9 and FIGS. 6 and 10, the polarization selection optical system and the modulation / color synthesis / projection optical system have the same basic configuration and optical system as those of the prior art. The only difference is that each optical element that handles blue light and red light is arranged in an inverse relationship with respect to a plane passing through the optical axis of the projection lens 16.

The features of the apparatus according to this embodiment reside in the configuration of the color separation / light guide optical system shown in FIGS. 2 and 3, and particularly in FIG. 4, and the arrangement of the optical elements. In each figure, 6 is a dichroic mirror that separates white light into magenta light (mixed color light of red light and blue light: rb) and green light g, 8 is a dichroic mirror that separates magenta light into red light r and blue light b, 7
G and 7R each indicate a reflection mirror. First, white light emitted from the light source 1 is converted into read light having a uniform illuminance distribution from which infrared light has been removed by the collimator lens 2, the first and second integrators 3 and 4, and the cold mirror 5. Although the direction is changed by 90 ° in the horizontal plane, the optical axis of the white light w after the direction change is parallel to the optical axis of the projection lens 16 of the modulation / color synthesis / projection optical system, and the polarization selection optical system (FIG. 5). ) Is set in the direction perpendicular to the optical axis of the condenser lens 11B.

The dichroic mirror is arranged such that the white light w is inclined at 45 ° to the optical axis.
6, the dichroic mirror 6 transmits the magenta light rb as it is, but reflects the green light g and
The direction is changed by 0 °. The dichroic mirror 6 is arranged at a position where the optical axis of the reflected green light g crosses the optical axis of the condenser lens 11G perpendicularly.

Green light g reflected by the dichroic mirror 6
Is incident on a reflection mirror 7G disposed immediately below the condenser lens 11G in a form inclined at 45 ° with respect to the optical axis, and is reflected by the reflection mirror 7G so as to be 90 ° in the vertical direction. The direction is changed and made incident on the condenser lens 11G. Further, the magenta light rb transmitted through the dichroic mirror 6 is incident on the dichroic mirror 8 disposed immediately below the condenser lens 11B in a state of being inclined by 45 ° with respect to the optical axis.

The dichroic mirror 8 transmits the red light r of the incident magenta light rb as it is, but reflects the blue light b and changes the direction by 90 ° in the vertical direction. Therefore, the blue light b enters the condenser lens 11B in the polarization selection optical system (FIG. 5). And, as shown in FIG.
The optical path length from the light source 1 to the reflection mirror 7G is equal to the optical path length from the light source 1 to the dichroic mirror 8, and the optical path length of the polarization separation optical system and the modulation / optical Since the color synthesis / projection optical system is an optical system having symmetry with respect to each primary color light, the spatial light modulator for the green light g and blue light b of the modulation / color synthesis / projection optical system from the light source 1 The optical path lengths up to 14G and 14B are equal.

On the other hand, the red light r transmitted through the dichroic mirror 8 is incident on a correction lens 9 arranged on the optical axis of the transmitted light, and after being subjected to a predetermined light collecting action by the lens 9,
The direction is changed by 90 ° in the horizontal plane by the reflection mirror 10,
The light is subjected to a predetermined light condensing action by another correction lens 9 ′ disposed on the optical axis after the direction change, and further, is changed in direction by 90 ° in a horizontal plane by a reflection mirror 10 ′. The light enters the reflection mirror 7R disposed directly below the condenser lens 11R in the polarization selection optical system (FIG. 5) in an inclined manner. Then, the red light r reflected by the reflection mirror 7R is made incident on the condenser lens 11R. That is, red light r
With respect to, a detour optical path is formed on the space side formed below the projection lens 16 of the modulation / color synthesis / projection optical system to guide light to the condenser lens 11R for the corresponding color, and the light source 1 emits red light. Correction lenses 9, 9 'in the bypass light path that the light path length to the spatial light modulator 14R for the light r is longer than the light path length for the green light g and the blue light b and color shading occurs.
To prevent this.

Incidentally, in the case of the projection type display device of this embodiment, the rectangular area defining the area occupied by the color separation / light guide optical system in a plane corresponds to the area 31 surrounded by the dotted line in FIG. The square area defining the area occupied by the color combining / projecting optical system in a plane corresponds to the area 32 surrounded by the dotted line in FIG.
32 included. Therefore, the external housing of the device is [(region 32
And the light source unit area 1 to 5) × (height for three layers)].

On the other hand, a projection display device shown in the prior art
In the case of (FIG. 7), a rectangular area defining the area occupied by the color separation / light guide optical system in a plane is an area surrounded by a dotted line in FIG.
A rectangular area corresponding to the area 33 and defining the area occupied by the modulation / color synthesis / projection optical system in a plane corresponds to an area 34 (equivalent to the area 32) surrounded by a dotted line in FIG. In this case, the region 33 is not included in the region 34, and greatly expands to both sides with respect to the region 34 by the arrangement region of the mirrors 17, 19R, 19B ', and 19B. As is clear from FIG. 7, the mirrors 17, 18, and 19 B greatly extend rearward by the arrangement area. Therefore, when designing the outer housing, [(region 33 and region
If the volume given by the rectangular area defining the area occupied by 34 and the area of the light source section 1 to 5) × (height of three layers) is a guide, it will be an extremely large housing, Even if the housing is designed so that the wall is formed along the outside of each optical element to reduce the volume, the area occupied in a plane is much larger than that of the embodiment and the housing is larger. The shape of the body becomes complicated, and in any case, the size of the apparatus is increased and the manufacturing cost is increased.

In other words, according to the apparatus of this embodiment, the color separation / light guide optical system is composed of two dichroic mirrors.
6, 8 and reflection mirrors 7G, 7R, 10, 10 'and correction lenses 9, 9' are configured in the minimum plane area to guide each primary color light to the polarization selection optical system, making the device extremely compact. It is possible to configure. In the projection display device shown in the prior art, six reflection mirrors 19R, 20R, 20G, 19B, 19B ', 2
Although 0B is used, the apparatus of this embodiment requires only four reflection mirrors 7G, 7R, 10, and 10 ', and the number of parts can be reduced.

In both the device shown in the prior art and the device of this embodiment, a polarization selection optical system is interposed as an intermediate layer, but the polarization selection optical system is not an essential optical system. This is because the polarization selection function can be provided in each of the polarization beam splitters 13G, 13B, and 13R of the modulation, color synthesis, and projection optical systems. This is because by selecting the components, it is possible to display a high-quality image with a high contrast ratio.

[0028]

According to the projection display apparatus of the present invention having the above configuration, the following effects can be obtained. According to a first aspect of the present invention, there is provided a projection display device in which a color separation / light guiding optical system and a modulation / color combining / projection optical system are configured for respective layers, wherein the color separation / light guiding optical system comprises two independent dichroic mirrors. And a plurality of reflection mirrors, it is possible to prevent the shadow of the intersection, unnecessary bright lines, and abnormal colors from being generated in the projected image as in the case of using an intersection type dichroic mirror. On the other hand, if the color separation / light guide optical system is configured as described above, it must be routed in such a manner as to bypass the optical path of at least one of the three primary color lights. By arranging the elements almost in a planar area corresponding to a rectangular area that defines the area occupied by the modulation / color combining / projection optical system in a planar manner, the size of the apparatus can be significantly reduced. According to a second aspect of the present invention, the bypass optical path is configured using a space formed on the side of the modulation / color combining / projection optical system on which the projection lens is disposed, and a correction lens is easily interposed in the bypass optical path. By making the optical path lengths of the primary color lights substantially equal, the purpose of reducing the size of the device and the measure for suppressing the occurrence of color shading are achieved at the same time. The third aspect of the present invention realizes a high-quality image display with a high contrast ratio by interposing a polarization selection optical system between each layer of the modulation / color synthesis / projection optical system and the color separation / light guide optical system. It should be noted that the device becomes larger in the vertical direction by that level due to the interposition of the polarization selection optical system. However, the size of the device is not so large as a whole.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an arrangement relationship of optical elements of a projection display device according to an embodiment of the present invention when viewed obliquely from above.

FIG. 2 is a perspective view showing an arrangement relationship of optical elements of the projection display device as viewed from an oblique side.

FIG. 3 is a perspective view showing an arrangement relationship of optical elements of the projection display device as viewed obliquely from below.

FIG. 4 is a plan view of the hierarchy of the light source unit and the color separation / light guide optical system as viewed from below.

FIG. 5 is a plan view of the hierarchy of the polarization selection optical system as viewed from below.

FIG. 6 is a plan view of the hierarchy of the modulation / color synthesis / projection optical system as viewed from below.

FIG. 7 is a side view of a projection display device according to the related art.

FIG. 8 is a plan view of the hierarchy of the light source unit and the color separation / light guide optical system as viewed from below.

FIG. 9 is a plan view of the hierarchy of the polarization selection optical system as viewed from below.

FIG. 10 is a plan view of the hierarchy of the modulation / color synthesis / projection optical system as viewed from below.

[Explanation of symbols]

1 ... Light source, 2 ... Collimator lens, 3,4 ... Integrator, 5 ... Cold mirror, 6,8,17,18 ... Dichroic mirror, 7G, 7R, 10,10 ', 19B, 19B', 19R, 20B, 20G , 20R… Reflection mirror, 9,9 ′… Correction lens, 11G, 11B, 11R… Condenser lens, 12G, 12B, 12R, 13G, 13B, 13R… Polarization beam splitter, 12b, 12g, 12r, 13b, 13g, 13r… Polarizing film, 14G, 14B, 14R…
Reflective spatial light modulator, 15 ... crossed dichroic prism for color synthesis, 15b, 15r ... dichroic mirror surface, 1
6 ... Projection lens, 31,33 ... Square area that defines the area occupied by the color separation / light guide optical system in a plane, 32,34 ... Square area that defines the area occupied by the modulation, color synthesis, and projection optical system in a plane region.

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H04N 9/31 H04N 9/31 C (72) Inventor Tetsuji Suzuki 3-12 Moriyacho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture Inside Victor Company of Japan, Ltd. 72) Inventor Fujiko Koyama 3-12-12 Moriyacho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture Inside the Victor Company of Japan (72) Inventor Tatsusaku Takahashi 3-12-12 Moriyacho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture Inside Victor Company of Japan (72) Inventor Yasuo Ishizaka 3-12-12 Moriyacho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture Inside Victor Company of Japan

Claims (3)

[Claims] 1. A projection lens is disposed on an exit surface of a cross-type dichroic prism in which wavelength-selective reflection films for two different colors of the three primary colors are crossed, and the exit surfaces are respectively provided for the three entrance surfaces. The polarization beam splitters were disposed in a manner of facing each other, and the reflection-type spatial light modulators were disposed facing each other on the surface of each of the polarization beam splitters on the side opposite to the cross-type dichroic prism. A modulation / color synthesis / projection optical system, and a color separation / light guide optical system which separates white light generated by a light source into three primary color lights and guides the white light to an entrance surface of each polarization beam splitter of the modulation / color synthesis / projection optical system. In the projection display device configured for each layer, the respective polarization beam splitters of the modulation / color synthesis / projection optical system are arranged such that their incident surfaces are on the layer side of the color separation / light guide optical system. Set the direction of the polarizing film and arrange it,
The color separation / light guide optical system is composed of two independent dichroic mirrors and a plurality of reflection mirrors, and these mirrors define a rectangular area which is occupied by the modulation / color synthesis / projection optical system in a plane. The light source is disposed so as to substantially fit within a planar area corresponding to the area, and the three primary color lights obtained by decomposing the white light of the light source are guided to the incident surfaces of the respective polarizing beam splitters. Projection display device. 2. The color separation / light guide optical system according to claim 1, wherein said first primary color light and said second primary color light out of three primary color lights are subjected to said modulation / color synthesis / light synthesis.
The optical path length from the light source is set to be equal to each of the polarizing beam splitters facing the adjacent incident surface of the cross type dichroic prism of the projection optical system, and the modulation, color synthesis, and projection are performed on the third primary color light. The optical system has an optical configuration in which an optical path is configured to bypass a space formed on the side where the projection lens of the optical system is disposed and is incident on another polarization beam splitter, and a third primary color light is included in the bypass optical path. 2. The projection display apparatus according to claim 1, further comprising a correction lens for making the optical path length from the light source to the polarization beam splitter substantially equal to the optical path lengths of the first and second primary color lights. . 3. A polarization selecting optical system is interposed between each layer of the modulation / color synthesizing / projection optical system and the color separation / light guiding optical system, and the polarization selecting optical system includes the modulation / color synthesizing / projection optical system. The system comprises three polarizing beam splitters disposed so as to be opposed to the incident surfaces of the respective polarizing beam splitters of the system, and transmits one polarized component of each primary color light to transmit each polarized light of the modulation / color synthesis / projection optical system. 3. The projection type display device according to claim 1, wherein the light is incident on a beam splitter and the other polarized light component is emitted in a hierarchical direction.