JP2003057744A - Projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection type display device which reduces ghost light to obtain a bright projection image. SOLUTION: A reflection light valve 112B for a first color, a reflection light valve 112R for a second color, a reflection light valve 112G for a third color, a polarizing beam splitter 111B for the first color, a polarizing beam splitter 111R for the second color, and a polarizing beam splitter 111G for the third color are so arranged that vibration directions of two of first detection light, second detection light, and third detection light may be inclined at about 900 to the vibration direction of the other detection light in a position C where these three detection light are made incident on a first dichroic film 113B or a second dichroic film 113R.

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,
More particularly, it relates to a full-color projection display device using a plurality of reflective light valves.

[0002]

2. Description of the Related Art A conventional projection type display device using a reflection type light valve is disclosed in, for example, Japanese Patent Laid-Open No. 10-268235.

[0003]

However, in the projection type display device disclosed in the above publication, randomly polarized light from the light source enters the optical system. Therefore, about half of the light amount is not projected and is discarded. Therefore, there is a problem that the projected image becomes dark. It is also conceivable to add a single polarization conversion device that converts random polarized light from a light source to single polarization to the optical system disclosed in the above publication. However, by simply adding the single polarization conversion device, one color light of the color-separated light source light passes through the polarization beam splitter. For this reason,
This one-color light has a problem that the light does not enter the light valve.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a projection type display device capable of reducing ghost light and obtaining a bright projection image.

[0005]

In order to solve the above-mentioned problems, in the invention described in claim 1, the polarization conversion devices 102, 10 for converting the light from the light source 101 into a substantially single linearly polarized light.
An illumination optical system having 3, 104, 105 and color separation optical systems 107, 110 for separating the light from the light source 101 into a first color light B, a second color light R and a third color light G, and an image display. A first color reflective light valve 112B having a first optical axis AXB extending substantially perpendicularly from the substantially center of the surface and modulating the first color light B based on an image signal, and substantially from the substantially center of the image display surface. A second optical axis AXR extending vertically,
The second color reflective light valve 112R that modulates the color light R based on the image signal, and the third optical axis AXG that extends substantially perpendicularly from the substantially center of the image display surface, and uses the third color light G as the image signal. Reflective light valve 11 for the third color that is modulated based on
2G and the first color light B are polarized and separated, emitted to the first color reflective light valve 112B, and the first color light B from the first color reflective light valve 112B is detected. The color polarization beam splitter 111B and the second
The color light R is polarized and separated and is emitted to the second color reflective light valve 112R, and the second color reflective light valve 1R is provided.
The second color polarization beam splitter 111R for detecting the second color light R from the 12R, and the third color light G are polarized and separated and are emitted to the third color reflection type light valve 112G to emit the third color light. For the third color polarization beam splitter 111G for detecting the third color light G from the reflection type light valve 112G for reflection, and the first color light B for reflecting the second color light R.
And the first dichroic film 113 that transmits the third color light G
B and a second dichroic film 113R that reflects the second color light R and transmits the first color light B and the third color light G.
And a projection optical system 114 for projecting light that is color-synthesized by the first dichroic film 113B and the second dichroic film 113R, and the first color polarization beam splitter 111B and the second color polarization. Beam splitter 1
11R is disposed at a position facing the first dichroic film 113B and the second dichroic film 113R, and the third color polarization beam splitter 111 is disposed.
G is disposed at a position facing each other through the first dichroic film 113B and the second dichroic film 113R, and the first optical axis AXB, the second optical axis AXR, and the third optical axis AXG. Intersect at the intersection C between the first dichroic film 113B and the second dichroic film 113R, and the first color reflective light valve 1
12B, travels along the first optical axis AXB,
The light detected by the polarization beam splitter 111B for the first color and incident on the first dichroic film 113B or the second dichroic film 113R is used as the first detection light, and the reflection type light valve 112R for the second color is used. Light that has traveled along the second optical axis AXR, is detected by the second color polarization beam splitter 111R, and is incident on the first dichroic film 113B or the second dichroic film 113R. Light from the third color reflective light valve 112G, travels along the third optical axis AXG, is detected by the third color polarization beam splitter 111G, and is detected by the first dichroic. Membrane 1
13B or the light incident on the second dichroic film 113R is referred to as the third analyzing light, the first analyzing light, the second analyzing light, and the third analyzing light are At the position C which is incident on the first dichroic film 113B or the second dichroic film 113R, the vibration directions of two of the three analysis lights are different from the vibration direction of the remaining one analysis light. The first so as to be tilted by approximately 90 degrees
The color reflective light valve 112B, the second color reflective light valve 112R, the third color reflective light valve 112G, and the first color polarization beam splitter 11
1B, the second-color polarization beam splitter 111R, and the third-color polarization beam splitter 111G are arranged to provide a projection type display device.

The projection display device according to a second aspect is the projection display device according to the first aspect, wherein the color separation optical systems 107 and 110 convert the light from the light source 101 into a first color light B. An optical system for color separation into a second color light R and a third color light G, the polarization beam splitter 111G of the color corresponding to the remaining one analysis light, and the color separation optical system 10.
The half-wave phase plate 11 in the optical path between the color-emission unit EXT corresponding to the remaining one of the analysis lights 7, 110.
And 5G.

The projection type display device according to a third aspect is the projection type display device according to the first aspect, wherein the color separation optical systems 107 and 110 are the polarization conversion devices 102 and
A wavelength-selective phase plate 115Gλ is provided in the optical path between 103, 104, 105 and the polarization beam splitter 111G of the color corresponding to the remaining one analysis light.

[0008]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

First, it is important to understand the cause of ghost light in order to explain the present invention. Therefore, the ghost light will be described first.

FIG. 8 is a diagram for explaining the cause of ghost light. A description will be given by taking ghost light of blue (B) light as an example. The light emitted from the B-light reflection type light valve 12B enters the polarization beam splitter 11B. The polarization beam splitter 11B detects only the modulated light as transmitted light and emits it to the cross dichroic prism 13 side. The cross dichroic prism 13 has a red (R) light reflection dichroic film 13R and a B light reflection dichroic film 13B. The R light reflection dichroic film 13R reflects R light and transmits B light and green (G) light. The B light reflection dichroic film 13B reflects B light and transmits R light and G light. The R light reflection dichroic film 13R and the B light reflection dichroic film 13B are arranged in a substantially X shape. The B light transmitted through the polarization beam splitter 11B is
Due to the optical design, B in the cross dichroic prism 13
It is reflected by the light reflection dichroic film 13B. Then, the reflected B light is emitted from the cross dichroic prism 13 to the projection lens 14 side.

However, the B-light reflecting dichroic film 13B does not have a reflectance of 100% with respect to the incident B-light. Therefore, the B-light reflecting dichroic film 13B inevitably transmits a part of the B-light although it is a minute amount. B light reflection dichroic film 1
The B light that has passed through 3B proceeds as it is and is emitted to the polarization beam splitter 11R side. The B light that has passed through the B light reflection dichroic film 13B is P-polarized light and therefore enters the polarization beam splitter 11R and is transmitted therethrough. The B light emitted from the polarization beam splitter 11R enters the reflection light valve 12R for R light. Reflective light valve for R light 1
The B light that has entered 2R is reflected, travels in the reverse direction, and again enters the polarization beam splitter 11R. The B light re-incident on the polarization beam splitter 11R is transmitted as it is and re-incident on the cross dichroic prism 13. The B light that has re-entered the cross dichroic prism 13 is reflected by the B light reflection dichroic film 13B. B B reflected by the light reflection dichroic film 13B
The light is emitted to the G light polarization beam splitter 11G side. The B light that has entered the polarization beam splitter 11G for the G light is P-polarized light, and therefore is transmitted and emitted. The B light emitted from the polarization beam splitter 11G for G light is incident on the reflection light valve 12G for G light. The B light that has entered the G light reflective light valve 12G is reflected and again enters the G light polarization beam splitter 11G. The B light that has entered the polarization beam splitter 11G for the G light is directly transmitted and emitted to the cross dichroic prism 13 side. B incident on the cross dichroic prism 13
Part of the light passes through the B-light reflection dichroic film 13B. The light transmitted through the B light reflection dichroic film 13B enters the projection lens 14. The projection lens 14 projects this light as ghost light onto a screen (not shown).

Although the above description uses B light as a representative example, the same applies to R light. The R light emitted from the reflection light valve 12R for the R light passes through the polarization beam splitter 11R and cross dichroic prism 13
Incident on. A part of the R light incident on the cross dichroic prism 13 passes through the R light reflecting dichroic film 13R. The R light transmitted through the R light reflection dichroic film 13R is transmitted through the polarization beam splitter 11B and is incident on the B light reflection type light valve 12B. The R light reflected by the reflection light valve 12B for B light passes through the polarization beam splitter 11B and enters the cross dichroic prism 13 again. Cross dichroic prism 1
The R light incident on the R3 is the R light reflecting dichroic film 13R.
Is reflected by. The R light reflected by the R light reflection dichroic film 13R passes through the polarization beam splitter 11G. The R light transmitted through the polarization beam splitter 11G is
The light enters the reflection type light valve 12G for light. The R light that has entered the reflective light valve 12G for G light is reflected and transmitted again through the polarization beam splitter 11G. The R light transmitted through the polarization beam splitter 11G enters the cross dichroic prism 13. A part of the R light incident on the cross dichroic prism 13 passes through the R light reflecting dichroic film 13R. R light reflection dichroic film 1
The R light transmitted through 3R is incident on the projection lens 14. The projection lens 14 projects the B light as ghost light onto the screen.

Next, the ghost light of G light will be described. There are two reasons why the ghost light of G light is generated. First, the first reason will be described. The G light emitted from the reflection type light valve 12G for G light is transmitted to the polarization beam splitter 11
G is transmitted. The G light transmitted through the polarization beam splitter 11G enters the cross dichroic prism 13. A part of the G light incident on the cross dichroic prism 13 is reflected by the R light reflection dichroic film 13R. The G light reflected by the R light reflection dichroic film 13R passes through the polarization beam splitter 11B and enters the B light reflection type light valve 12B. The G light reflected by the reflection light valve 12B for B light is transmitted through the polarization beam splitter 11B and cross dichroic prism 13 is transmitted.
Incident on. Part of the G light that has entered the cross dichroic prism 13 is reflected by the B light reflection dichroic film 13B and enters the projection lens 14. Projection lens 14
Projects G light as ghost light on a screen (not shown).

The remaining G light incident on the cross dichroic prism 13 is R light reflection dichroic film 13R,
The light passes through the B-light reflecting dichroic film 13B and proceeds.
The G light transmitted through the cross dichroic prism 13 is
The light passes through the polarization beam splitter 11R and enters the reflection light valve 12R for R light. The G light that has entered the R-light reflection type light valve 12R is reflected and goes backward. The G light reflected by the reflection light valve for R light 12R passes through the polarization beam splitter 11R and enters the cross dichroic prism 13. A part of the G light incident on the cross dichroic prism 13 is reflected by the R light reflection dichroic film 13R. R light reflection dichroic film 1
The G light reflected by 3R enters the projection lens 14.
The projection lens 14 projects the G light as ghost light onto a screen (not shown).

Next, the second reason why G ghost light is generated will be described. Reflective light valve for G light 12
The G light emitted from G passes through the polarization beam splitter 11G. The G light transmitted through the polarization beam splitter 11G enters the cross dichroic prism 13. A part of the G light incident on the cross dichroic prism 13 is reflected by the B light reflecting dichroic film 13B. B
The G light reflected by the light reflection dichroic film 13B passes through the polarization beam splitter 11R and enters the R light reflection type light valve 12R. The G light reflected by the reflection light valve 12R for R light is polarized beam splitter 11
The light passes through R and enters the cross dichroic prism 13. G incident on the cross dichroic prism 13
Part of the light is reflected by the R light reflection dichroic film 13R and enters the projection lens 14. The projection lens 14 is G
The light is projected as ghost light on a screen (not shown).

The remaining G light incident on the cross dichroic prism 13 is reflected by the R light reflecting dichroic film 13R,
The light passes through the B-light reflecting dichroic film 13B and proceeds.
The G light transmitted through the cross dichroic prism 13 is
The light passes through the polarization beam splitter 11B and enters the B-light reflection type light valve 12B. The G light that has entered the B light reflection type light valve 12B is reflected and travels backward. The G light reflected by the reflection light valve 12B for B light passes through the polarization beam splitter 11B and enters the cross dichroic prism 13. The G light incident on the cross dichroic prism 13 is reflected by the B light reflecting dichroic film 1
It is reflected at 3B. The G light reflected by the B light reflecting dichroic film 13B enters the projection lens 14. The projection lens 14 projects the G light as ghost light onto a screen (not shown).

For the reasons described above, ghost lights of B light, G light, and R light are generated. Next, an embodiment according to the present invention for reducing the ghost light will be described.

(First Embodiment) FIG. 1 is a block diagram showing a first embodiment of a projection type display device of the present invention. A light source 101 including a lamp and a parabolic concave mirror supplies a light beam of a substantially parallel light flux. The substantially parallel light flux from the light source 101 enters the first lens plate 102 on which the plurality of lens elements 102a are arranged in a plane. First lens plate 102
The light incident on is divided into the number of light fluxes of the lens element 102a by the aperture defined by the outer shape of the lens element 102a. The plurality of lens elements 102a are
The respective outer shapes are all the same and are a proportionally reduced shape of an illuminated portion of a reflection type light valve described later.

The lens element 102a of the first lens plate 102
At the focal point position of the second lens element 103a, the lens element 103a corresponding to each lens element 102a is arranged in a plane.
The lens plate 103 is arranged. That is, the first lens plate 102 and the second lens plate 103 constitute a so-called fly eye integrator. The lens element 102a of the first lens plate 102 and the lens element 103 of the second lens plate 103
a has the above configuration. Therefore, the lens element 102
The light flux incident on a is focused on the corresponding lens element 103a to form a bright spot on the lens element 103a.

In the vicinity of the exit surface of the second lens plate 103, there is arranged a polarization beam splitter array 104 in which a plurality of polarization beam splitters 104p are formed in an array shape with their polarization splitting portions in parallel. The polarization beam splitter 1
The width of 04p corresponds to the lens element 1 of the second lens plate 103.
It is about 1/2 of the width of 03a. In addition, the lens element 103
The polarization beam splitter 104p is arranged so that the center of the polarization beam splitter 104p substantially coincides with the boundary portion of a and the central portion of the lens element 103a.

Of the polarization beam splitters 104p constituting the polarization beam splitter array 104, the exit surface of the polarization beam splitter 104p arranged at the position corresponding to the boundary of the lens element 103a of the second lens plate 103 is 1/2. The wave plate 105 is arranged.

Lens element 103a of the second lens plate 103
The light emitted from the bright spots formed on the light beams enters the polarization beam splitters 104p near the respective emission surfaces. Then, the P-polarized light transmitted through the polarization beam splitter 104p and the S-polarized light reflected and incident on the adjacent polarization beam splitter 104p are polarized and separated.

Further, the S-polarized light incident on the adjacent polarization beam splitter is reflected by the polarization separation section of the polarization beam splitter and exits. Here, the half-wave plate 105 is arranged on this exit surface as described above. Therefore, S-polarized light is converted into P-polarized light and emitted.

As described above, in this embodiment, all the light source light is converted into P-polarized light, and the light emitted from the plurality of bright spots on the lens 103a of the second lens plate 106 through the condenser lens 106 will be described later. The reflective light valve is superposed and illuminated.

Hereinafter, an optical device composed of the first lens plate 102, the second lens plate 103, and the polarization beam splitter array 104 in which the ½ wavelength plate 105 is arranged is referred to as a polarization conversion device.

The light, which has been converted into P-polarized light by the polarization converter through the condenser lens 106, enters the cross dichroic mirror 107. The cross dichroic mirror 107 includes a dichroic mirror 107RG that reflects R light and G light and transmits B light on the optical axis, and a dichroic mirror 107B that reflects B light and transmits R light and G light.
And are arranged in an X shape so as to be orthogonal to each other.

The light incident on the cross dichroic mirror 107 is color-separated into B light and mixed light of R light and G light. The B light changes its direction at the bending mirror 108 and travels, and enters the polarization beam splitter 111B for the B light. Since the B light is P polarized, the polarization beam splitter 1
The light passes through the polarized light separating portion 111Bp of 11B and is emitted. Then, the light enters the B-light reflection type light valve 112B arranged near the exit surface of the polarization beam splitter 111B.

On the other hand, the mixed light of the R light and the G light travels while changing the direction in the bending mirror 109, and is incident on the G light reflecting dichroic mirror 110 arranged on the optical axis. G
The light reflection dichroic mirror 110 separates the mixed light of the R light and the G light into the reflected G light and the R light that passes through and propagates.

The R light is a polarization beam splitter 1 for the R light.
It is incident on 11R. The polarization beam splitting unit 111Rp transmits and emits R light. Polarization beam splitter 111 for R light
The R light emitted from R enters the reflection light valve 112R for R light arranged near the emission surface.

The G light reflected by the G light reflecting dichroic mirror 110 is converted into S polarized light by passing through the ½ wavelength phase plate 115G. The G light converted into S-polarized light is G
The light enters the polarization beam splitter 111G for light. The polarized light separating section 111Gp reflects and emits G light. The G light emitted from the polarization beam splitter 111G for G light is reflected by a G light reflection light valve 112G disposed near the emission surface.
Incident on.

The fast axis and the slow axis of the ½ wavelength phase plate 115G are inclined by 45 degrees with respect to the vibration direction of the polarized light incident on the ½ wavelength phase plate 115G.

In order to position the ½ wavelength phase plate 115G as described above, the ½ wavelength phase plate 11 is formed by the following procedure.
Adjust 5G.

At least G light is projected on the screen 117. Then, the manufacturer rotates the ½ wavelength phase plate 115G and ½ at the position where the projected image becomes brightest.
The wavelength phase plate 115G is stopped. Once positioned, 1 /
The two-wavelength phase plate 115G is fixed to a mounting member (not shown) with an adhesive.

The light reflected and emitted from the R-light reflective light valve 112R and the B-light reflective light valve 112B is a mixed light containing S-polarized light which is modulated light and P-polarized light which is unmodulated light. . This mixed light enters the polarization beam splitter for each color light. The polarization splitting unit of the polarization beam splitter for each color light detects and extracts S-polarized light, which is modulated light, as reflected light. The analysis light enters the cross dichroic prism 113 that constitutes the color combining optical system from different surfaces.

The light reflected and emitted from the G light reflection type light valve 112G is a mixed light of P polarized light which is modulated light and S polarized light which is non-modulated light. Polarization beam splitter 111
The G polarization separation unit 111Gp detects and extracts P-polarized light, which is modulated light, as transmitted light. Polarization beam splitter 11
The G light emitted from 1G enters the cross dichroic prism 113 as a combined light from a surface different from the R light and the G light.

The cross dichroic prism 113 is
This is a composite prism member in which an R light reflection dichroic film 113R and a B light reflection dichroic film 113B are arranged inside in an X-shape so as to be orthogonal to each other. The R light reflection dichroic film 113R has a property of reflecting R light and transmitting B light and G light. B light reflection dichroic film 1
13B has a characteristic of reflecting B light and transmitting R light and G light. The R light and B light that have entered the cross dichroic prism 113 are reflected by the R light reflection dichroic film 113R and the B light reflection dichroic film 113B, respectively.

The G light is emitted from both dichroic films 113.
After passing through R and 113B, they are emitted as three-color composite light. Then, the combined light enters the projection lens 114, and a full-color image is projected on the screen 117.

In this embodiment, of the R, G, and B lights incident on the cross dichroic prism 113, the R and B lights that are reflected by the dichroic film are S-polarized and the G lights that are transmitted. With respect to, color synthesis can be performed by making P-polarized light incident. For this reason, it is possible to project a high-luminance projection image even in consideration of the dichroic separation characteristics of the S-polarized light and the P-polarized light of the dichroic film.

Next, the reason why the ghost light projection can be reduced in the embodiment of the projection type display device shown in FIG. 1 will be described with reference to FIG. FIG. 2 is a diagram showing a light valve for each color light, a polarization beam splitter for each color light, a cross dichroic prism, a projection lens and the like in FIG. Then, the ghost light passing through these members is shown.

Of the light emitted from the B-light reflection type light valve 112B, the S-polarized light which is the modulated light is reflected by the polarization beam splitter 111B and travels as described above. The B light emitted from the polarization beam splitter 111B enters the cross dichroic prism 113. Most of the B light incident on the cross dichroic prism 113 is B
The light is reflected by the light reflection dichroic film 113B and enters the projection lens 114.

On the other hand, a part of the B light passes through the B light reflecting dichroic film 113B and proceeds. The B light that has passed through the B light reflection dichroic film 113B exits the cross dichroic prism 113 and enters the polarization beam splitter 111R for the R light. Since this B light is S polarized light, it is reflected by the polarization beam splitter 111R and emitted. The B light emitted from the polarization beam splitter 111R enters the reflection light valve 112R for R light,
reflect. Then, again the polarization beam splitter 111R
Is incident on and reflected from. The B light emitted from the polarization beam splitter 111R is cross dichroic prism 113.
Incident on. The B light incident on the cross dichroic prism 113 is reflected by the B light reflection dichroic film 113B and emitted. Cross dichroic prism 1
The B light emitted from 13 enters the polarization beam splitter 111G for G light. Here, the incident B light is reflected by the polarization splitting portion of the polarization beam splitter 111G in S
It is polarized light. Therefore, the B light is reflected by the polarization splitting portion of the polarization beam splitter 111G, is excluded from the optical axis, and is discarded. The optical path through which the unwanted B light is discarded is described by the solid arrow in FIG. Therefore, B
It is possible to reduce the incidence of light entering the projection lens 114 and being projected as ghost light.

In this way, the polarization beam splitter 111
Only G detects light in the vibration direction parallel to the paper surface. Therefore, the polarization beam splitter 111G serves as an outlet for unnecessary light.

The light from the R-light reflection type light valve 112R which is transmitted through the cross dichroic prism 113 is similarly polarized beam splitter 111.
It is reflected by G and can be discarded from the optical axis.

Also, a reflection type light valve for G light 112G
The analysis light that has passed through the polarization beam splitter 111G among the light from the above enters the cross dichroic prism 113. The G light incident on the cross dichroic prism 113 is partially reflected by the B light reflection dichroic film 113B or the R light reflection dichroic film 113R to proceed (illustrated by a dotted line in FIG. 2). Then, the polarization beam splitter 111R or the polarization beam splitter 111
It is incident on B. Here, since the G light is P-polarized light, it can be transmitted through the polarization beam splitters 111R and 111B and discarded from the optical axis. Therefore, like the B light and the R light, they do not enter the projection lens 114 and do not constitute ghost light.

The configuration of this embodiment will be further described. The B-light reflection type light valve 112B has a first optical axis AXB extending substantially vertically from the substantially center of the image display surface,
The first color light (B light) is modulated based on the image signal.

The R-light reflection type light valve 112R has a second optical axis AXR extending substantially vertically from the substantially center of the image display surface.
And modulates the second color light (R light) based on the image signal.

The reflection light valve 112G for G light has a third optical axis AXG extending substantially vertically from the substantially center of the image display surface.
And modulates the third color light (G light) based on the image signal.

The polarization beam splitter 111B for B light is
The first color light (B light) is polarized and separated, and is emitted to the B light reflection type light valve 112B.
The first color light (B light) from 2B is detected.

The polarization beam splitter 111R for R light is
The second color light (R light) is polarized and separated and is emitted to the R light reflection type light valve 112R, and the R light reflection type light valve 11 is formed.
The second color light (R light) from 2R is detected.

The polarization beam splitter 111G for G light is
The third color light (G light) is polarized and separated, and is emitted to the G light reflection type light valve 112G.
The third color light (G light) from 2G is detected.

B light polarization beam splitters 111B and R
The polarization beam splitter 111R for light is the B light reflection dichroic film 113B and the R light reflection dichroic film 11B.
It is arranged at a position facing with 3R.

The polarization beam splitter 111G for G light is
The B light reflection dichroic film 113B and the R light reflection dichroic film 113R are arranged to face each other.

The first optical axis AXB and the second optical axis A
XR and the third optical axis AXG intersect at an intersection C between the B light reflection dichroic film 113B and the R light reflection dichroic film 113R.

Then, the reflection type light valve 112 for B light is used.
B is emitted, travels along the first optical axis AXB, is detected by the B light polarization beam splitter 111B, and is incident on the B light reflection dichroic film 113B or the R light reflection dichroic film 113R. Use light for analysis.

The R light reflection light valve 112R is emitted, travels along the second optical axis AXR, is detected by the R light polarization beam splitter 111R, and is reflected by the B light reflection dichroic film 113B or the R light reflection dichroic film. Membrane 113
The light incident on R is the second analysis light.

The G light reflection type light valve 112G is emitted, travels along the third optical axis AXG, is detected by the G light polarization beam splitter 111G, and is reflected by the B light reflection dichroic film 113B or the R light reflection dichroic film. Membrane 113
The light incident on R is the third analysis light.

The first light, the second light and the third light are B-light reflecting dichroic film 113B.
Alternatively, at the position C which is incident on the R light reflection two dichroic film 113R, the vibration direction of two of the three analysis lights (B light, R light) is the remaining one analysis light (G light).
B light reflection type light valve 112B and R light reflection type light valve 1 so as to be inclined 90 degrees with respect to the vibration direction of (light).
12R and G light reflection type light valve 112G, polarization beam splitter 111B and polarization beam splitter 111
R and the polarization beam splitter 111G are arranged.

The color separation optical systems 107 and 110 are optical elements for separating the light from the light source 101 into first color light (B light), second color light (R light) and third color light (G light). System,
The polarization beam splitter 111G of the color (G light) corresponding to the remaining one analysis light and the color separation optical system 10
The half-wave phase plate 115G is provided in the optical path between the color and the emission portion EXT of the color (G light) corresponding to the remaining one detection light of 7, 110.

With this structure, as described above, the projection lens 114 emits the ghost light generated from the imperfections of the dichroic film in the cross dichroic prism 113.
It can be discarded from the optical axis by utilizing the polarization separation characteristic of the polarization beam splitter before entering the optical axis. For this reason,
It is possible to reduce the projection of ghost light and improve the contrast of the projected image. (Second Embodiment) FIG. 3 is a view showing the schematic arrangement of a projection type display device according to the second embodiment. Note that, as shown in the figure, the X axis, the Y axis, and the Z axis (directions perpendicular to the plane of the drawing) that are perpendicular to each other are defined.

The configurational difference from the first embodiment is the arrangement direction of the polarization separation film of the polarization beam splitter for each color. In this embodiment, each color light is made incident on each polarization beam splitter from a direction perpendicular to the paper surface (direction parallel to the Z axis).

In this embodiment, the polarization conversion device is configured to convert the source light into S-polarized light (the vibration direction is parallel to the Z axis). Compared to the polarization conversion device of the first embodiment, 1
The position of the / 2 wavelength phase plate 105 is different. Light source 10
Other configurations from 1 to the condenser lens 106 are
Since it is the same as that of the above-described first embodiment, duplicated description will be omitted.

Regarding the polarization beam splitters for the respective color lights, the direction of the polarization splitting part is different from that in the first embodiment described above in the B direction.
Regarding the polarization beam splitter 111B for light and the polarization beam splitter 111R for R light, the S polarization reflected when the R light and the B light respectively enter from the −Z axis direction perpendicular to the paper surface in FIG. Direction, it is arranged so as to reflect and travel in the -Y axis direction. Further, the polarization beam splitter 111G for G light is arranged so that the S-polarized light reflected when entering from the −Z direction is reflected in the −X direction.

FIG. 4 is a perspective view of the portion shown in FIG. The projection lens 114 is not shown for simplification. As described above, the polarized beam splitters 111B, 111G, and 111 for the respective colored lights are used for the respective colored lights from the −Z direction.
Bending mirror 11 for making light incident on R from the −Z direction
6B, 116G, and 116R are arranged as shown in the figure. In addition, in the present embodiment, for the G light, the ½ wavelength plate 115G is arranged before entering the polarization beam splitter 111G. The light valve 112G is arranged near the emission surface of the light that passes through the polarization beam splitter 111G.

With this configuration, the polarized light by the polarization converter is linearly polarized light in the Z-axis direction, and the bending mirror 1
The light reflected by 16B and 116R becomes linearly polarized light in the X-axis direction. Therefore, the polarization beam splitter 111 for R light is used.
With respect to the R polarization separation section 111Rp and the polarization separation section 111Bp of the polarization beam splitter 111B for B light, the polarization polarization section 111Rp enters the respective polarization beam splitters as the polarization having the oscillation direction of the S direction. Therefore, the R light and the B light that have entered the respective polarization beam splitters are reflected by the polarization splitting unit and emitted. Then, the light enters the reflective light valves 112R and 112B arranged near the exit surface.

On the other hand, the G light is the polarization beam splitter 11
Before entering 1 G, the ½ wavelength plate 115 changes the vibration direction by 90 degrees. Therefore, the G light becomes linearly polarized light in the X-axis direction. This G light is polarized light having a vibration direction of P direction for the polarization splitting portion 111Gp of the polarization beam splitter 111G. Therefore, the light passes through the polarization beam splitter 111G and enters the G light reflection type light valve 112G disposed near the exit surface.

The light reflected and emitted from the R-light reflection type light valve 112R and the B-light reflection type light valve 112B enters the polarization beam splitters 111R and 111B. The polarization beam splitters 111R and 111B detect only the modulated light as transmitted light. Then, the analysis light is used as the cross dichroic prism 1 that constitutes the color combining optical system.
It is incident on 13.

The light reflected and emitted from the reflection light valve 112G for G light enters the polarization beam splitter 111G. The polarization beam splitter 111G detects the modulated light as reflected light. The analysis light is incident on the cross dichroic prism 113.

The R light and B light incident on the cross dichroic prism 113 are polarized lights having an oscillation direction of S direction with respect to the dichroic film surface. The G light is polarized light having a vibration direction of P direction with respect to the surface of the dichroic film. Therefore, high-intensity projection can be achieved as in the first embodiment.

Also in the present embodiment, as shown in FIG. 5, a part of the B light emitted from the B light reflection type light valve 112B (shown by a solid line in FIG. 5) is generated by the dichroic film in the cross dichroic prism 113. Permeate and eject. The B light emitted from the cross dichroic prism 113 passes through the polarization prism 111R and enters the reflection light valve for R light 112R. Light incident on the R-light reflection type light valve 112R is reflected as it is,
The light enters the cross dichroic prism 113 again.
The light incident on the cross dichroic prism 113 is
It is reflected by the dichroic film. The B light reflected by the dichroic film is polarized by the polarization beam splitter 111 for G light.
It is transmitted through G and discarded from the optical axis. Therefore, this B
Light is never projected as ghost light.

Although illustration is omitted for simplicity, the R light is not projected as a ghost light like the B light. Further, the light emitted from the G light reflective light valve 112G (shown by the dotted line in FIG. 5) and reflected by the dichroic film in the cross dichroic prism 113 is the R light polarization beam splitter 11.
It is reflected by the polarization splitting unit of the polarization beam splitter 111B for 1R or B light. As a result, since it is similarly discarded from the optical axis, it is not projected as ghost light. (Third Embodiment) FIG. 6 is a view showing the schematic arrangement of a projection type display apparatus according to the third embodiment. In addition, FIG.
It is a perspective block diagram of the main part. In order to explain the directions, the X axis, the Y axis, which are axes orthogonal to each other as shown in the drawing,
The Z axis is defined (the Z axis is the direction perpendicular to the paper surface of FIG. 6).

In this embodiment, the first lens plate 10
2, the second lens plate 103, the polarization beam splitter array 104 and the half-wave plate 105, the polarized light emitted from the polarization converter is S-polarized light (light having a polarization direction parallel to the Z axis). And

The S-polarized light from the polarization converter enters the cross dichroic mirror 507. The cross dichroic mirror 507 reflects the R light and reflects the B light and the dichroic mirror 507R that transmits the G light and the B light.
A dichroic mirror 507B that transmits G light and R light is arranged in an X shape so as to be orthogonal to each other. The light source light that has entered the cross dichroic mirror 507 in the X direction is R light that is reflected in the Y axis direction, B light that is reflected in the −Y axis direction, and is transmitted in the X axis direction that is the same direction as the incident optical axis. The color is separated into three colors, G light and green light.

The B light and the R light are respectively bent by the bending mirror 10.
8 and 109 change the direction and proceed in the X direction. Next, the R light, the G light, and the B light are respectively bent by the bending mirror 116.
-Z incident on R, 116G, 116B and perpendicular to the paper surface
It can be bent in the axial direction. Then, the polarization beam splitters 111R, 111G, 1 arranged below the respective mirrors
It is incident on 11B.

The polarization splitting portion of the polarization beam splitter 111R for R light is arranged so that S-polarized light reflected on incident light from the -Z axis direction is reflected in the Y axis direction.
The polarization splitting portion of the polarization beam splitter 111B for B light is arranged so that S-polarized light reflected on incident light from the −Z axis direction is reflected in the −Y axis direction. The polarization splitting unit of the polarization beam splitter 111G for G light is arranged so that S-polarized light reflected on incident light from the −Z axis direction is reflected in the −X axis direction.

Since the polarization conversion device emits S-polarized light, the light from the light source has a vibration direction parallel to the Z axis when the light is emitted from the polarization conversion device. For this reason, when the R light and the B light are incident on the polarization beam splitters of the respective color lights, the polarized light having the vibration in the S direction with respect to the polarization separation unit,
The G light is incident on the polarization splitting portion of the polarization beam splitter as polarized light having vibration in the P direction.

Therefore, the R light incident on the polarization beam splitter 111R for the R light is reflected and emitted in the Y-axis direction. The B light incident on the polarization beam splitter 111B for the B light is reflected and emitted in the −Y axis direction. The G light that has entered the polarization beam splitter 111G for G light is transmitted and emitted.

A polarization beam splitter 111R for each color light,
Reflective light valves 112R, 112B and 112G for the respective color lights are arranged in the vicinity of the exit surfaces of 111G and 111B. Reflective light valves 112R, 112 for each color
B and 112G modulate incident light, reflect it, and emit it. Polarization beam splitters 111R, 111G, 111 for each color light
B detects the modulated light.

With this configuration, the analysis light from the R-light polarization beam splitter 111R can be detected by the polarization beam splitter 11R.
Proceed in the -Y-axis direction through 1R. The analysis light from the B-light polarization beam splitter 111B passes through the polarization beam splitter 111B and travels in the Y-axis direction. The analysis light from the G-light polarization beam splitter 111G is reflected by the polarization beam splitter 111G and travels in the X-axis direction. Then, the cross dichroic prism 113 achieves color combination of the incident lights and emits the lights in the X-axis direction. A projection lens (not shown) projects a full-color image.

For the dichroic surfaces 113B and 113R in the cross dichroic prism 113, R
Light and B light are incident as light having a vibration direction of S direction, G light
Light enters as light having a vibration direction of P direction. Therefore, a high-intensity projection image can be emitted as color-combined light.

Also in the projection type display device of this embodiment,
Ghost light can be discarded from the optical axis by the same operation as that of the second embodiment shown in FIG. 5, and a projected image with good contrast can be projected.

Incidentally, 1 / of the first and second embodiments
Wavelength selective phase plate 11 for G instead of the two-wave plate 115G
5Gλ may be used. Wavelength selective phase plate 115Gλ
Is arranged in the optical path between the polarization conversion devices 102, 103, 104 and 105 and the polarization beam splitter 111G of the color (G light) corresponding to the remaining one analysis light.

This G wavelength selective phase plate is one of the color deflectors disclosed in, for example, Japanese Patent Publication No. 11-504441, and has a characteristic of converting the polarization direction of G light by 90 °. Therefore, the G wavelength selective phase plate may be arranged anywhere in the optical path from the condenser lens 106 to the polarization beam splitter 111G. Wavelength-selective phase plates are currently expensive, but they have design freedom.

[0083]

As described above, it is possible to provide a projection type display device capable of reducing ghost light and obtaining a bright projected image.

[Brief description of drawings]

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

FIG. 2 is a diagram illustrating discarding of ghost light in the first embodiment.

FIG. 3 is a diagram showing a configuration of a projection type display device according to a second embodiment of the invention.

FIG. 4 is a perspective configuration diagram of a main part in the second embodiment.

FIG. 5 is a diagram illustrating discarding of ghost light in the second embodiment.

FIG. 6 is a diagram showing a configuration of a projection type display device according to a third embodiment of the invention.

FIG. 7 is a perspective configuration diagram of a main part in the third embodiment.

FIG. 8 is a diagram illustrating generation of ghost light in a conventional example.

[Explanation of symbols]

101 light source 102 first lens plate 103 Second lens plate 104 Polarizing beam splitter array 105 1/2 wave plate 106 Condenser lens 107,507 Cross dichroic mirror 108, 109 folding mirror 110 dichroic mirror 111R, 111G, 111B polarization beam splitter 112R, 112G, 112B Reflective light valve 113 Cross dichroic prism 114 Projection lens 115G 1/2 wave plate 116R, 116G, 116B Bending mirror 117 screen AXB, AXG, AXR optical axis C intersection EXT injection position

Claims (3)

[Claims] 1. A polarization conversion device for converting light from a light source into substantially single linearly polarized light, and light from the light source having a first color light and a second color light.
An illumination optical system having a color separation optical system for color separation into color light and a third color light, and a first optical axis extending substantially perpendicularly from substantially the center of the image display surface, and the first color light as an image signal. A reflection type light valve for the first color which is modulated based on the above, and a reflection type for the second color which has a second optical axis which extends substantially perpendicularly from the substantial center of the image display surface and which modulates the second color light based on the image signal. A light valve, a third color reflective light valve having a third optical axis extending substantially perpendicularly from the substantial center of the image display surface and modulating the third color light based on an image signal, and the first color light A polarization beam splitter for a first color that separates polarized light and emits it to the reflective light valve for the first color, and detects the first color light from the reflective light valve for the first color; The polarized light is separated and emitted to the reflection type light valve for the second color, A polarization beam splitter for the second color that detects the second color light from the reflection type light valve, and polarization-separates the third color light to be emitted to the reflection type light valve for the third color for the third color. A polarization beam splitter for a third color that detects the third color light from a reflective light valve; a first dichroic film that reflects the first color light and transmits the second color light and the third color light; A second dichroic film that reflects the second color light and transmits the first color light and the third color light; and a projection optical system that projects light that is color-synthesized by the first dichroic film and the second dichroic film. The first color polarization beam splitter and the second color polarization beam splitter are arranged at positions facing each other through the first dichroic film and the second dichroic film, and The three-color polarization beam splitter is arranged at a position facing each other through the first dichroic film and the second dichroic film, and the first optical axis, the second optical axis, and the third optical axis. Means that the first dichroic film intersects with the second dichroic film at the intersection, emits the first color reflective light valve, and travels along the first optical axis to generate the first color polarized light. The light that is detected by the beam splitter and is incident on the first dichroic film or the second dichroic film is the first light to be detected, which is emitted from the reflective light valve for the second color and the second optical axis. The light traveling along the second color polarization beam splitter and detected by the second color polarization beam splitter and incident on the first dichroic film or the second dichroic film is used as second analysis light, and the third color reflective light Valve The light emitted, traveling along the third optical axis, detected by the polarization beam splitter for the third color, and incident on the first dichroic film or the second dichroic film is referred to as the third detection light. In each case, at the position where the first light, the second light and the third light are incident on the first dichroic film or the second dichroic film, the three light beams are detected. The reflection type light valve for the first color and the reflection type for the second color are arranged so that the vibration directions of two of the detected lights are inclined by about 90 degrees with respect to the vibration direction of the remaining one of the detected lights. Type light valve, the reflection light valve for the third color, the polarization beam splitter for the first color, the polarization beam splitter for the second color, and the polarization beam splitter for the third color are arranged. Projection display device. 2. The projection display device according to claim 1, wherein the color separation optical system color-separates the light from the light source into first color light, second color light, and third color light. 1/2 in the optical path between the polarization beam splitter of the color corresponding to the remaining one analysis light and the emission portion of the color corresponding to the remaining one analysis light of the color separation optical system. A projection display device comprising a wavelength phase plate. 3. The projection display device according to claim 1, wherein the color separation optical system includes the polarization conversion device and the remaining one.
A projection type display device having a wavelength-selective phase plate in an optical path between the polarizing beam splitters of colors corresponding to one analysis light.