JP2001350132A - Liquid crystal projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal projector that can be easily assembled with good accuracy, can be decreased in cost and can be made high in luminance and accuracy. SOLUTION: The projector is equipped with a light source 1 which emits light of S polarization direction, a prism part 8 formed by crossing a PBS8b which transmits the P polarization component and reflects the S polarization component and a dichroic face 8a which reflects the red component and transmits the blue and green color components, first, second and third reflection type optical modulating devices 32, 33, 42 which modulate the respective components of the above three colors, and an projection optical system 6 which enlarges and projects the synthesized light of the color components.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-panel type liquid crystal projector using three reflection-type light modulation elements.
In particular, it relates to a liquid crystal projector device that can be reduced in size.

[0002]

2. Description of the Related Art An example of a projection unit of a conventional liquid crystal projector using a reflection type liquid crystal panel is shown in FIG.

As shown in FIG. 11, in this liquid crystal projector, light emitted from a light source 101 composed of a lamp 101a and a reflector 101b is converted into S-polarized white light by a polarizing plate 101c, and the emitted S-polarized white light is emitted. A dichroic mirror 102 that selectively reflects light of a red component (hereinafter, referred to as red light); a total reflection mirror 103;
A configuration is provided in which each of the three primary colors RGB is separated using a dichroic mirror 104 that selectively reflects light of a green component (hereinafter, referred to as green light).

[0004] The red light reflected and separated by the dichroic mirror 102 is polarized by a polarizing beam splitter (hereinafter referred to as PBS).
After being incident on one principal surface of the incident light 105, the light is reflected by a polarization separation surface that reflects the S-polarized light component in a direction orthogonal to the incident light, and is incident on a reflective liquid crystal panel 106 for red.
In the reflective liquid crystal panel 106 for red, the polarization direction of the red light incident on the pixel of the portion to be displayed in red is rotated by 90 degrees, that is, converted into P-polarized light and reflected based on the red image information. Therefore, the P-polarized light component of the red light that has entered the PBS 105 again passes through the polarization separation surface, and is incident on the first main surface of the dichroic prism 111 for color synthesis.

[0005] Green light and blue light transmitted through the dichroic mirror 102 are reflected by the total reflection mirror 103 in a direction orthogonal to the incident light, and are reflected by the dichroic mirror 1.
04. In the dichroic mirror 104,
Of the incident light, green light is reflected and separated in a direction orthogonal to the incident light, and is incident from one main surface of the PBS 107. As in the case of the red light, the green light is emitted from a direction orthogonal to the incident light after the pixel of a portion to be displayed in green in the reflective liquid crystal panel 108 for green is converted into P-polarized light, The light is incident on the second main surface of the color synthesizing dichroic prism 111.

Further, the blue light transmitted through the dichroic mirror 104 is, like the red light and the green light, after the pixels of the portion to be displayed in blue on the blue reflective liquid crystal panel 110 are converted into P-polarized light. Are emitted from a direction orthogonal to the incident light, and are incident on the third main surface of the color synthesizing dichroic prism 111.

When the image light of each of the three primary colors RGB enters from the three main surfaces of the dichroic prism 111 for color synthesis, the light is synthesized on the dichroic surface and then emitted from the projection optical system 112. A color image is displayed on a screen (not shown).

However, in such a conventional liquid crystal projector, since the reflection type liquid crystal panels are arranged in each of the three PBSs surrounding the three sides of the dichroic prism, the color separation for the color separation so as to go around the outside of the PBSs. It is necessary to dispose a dichroic mirror and the like, and there is a problem that the device becomes large. In particular, when used as a projection unit of a rear-projection type liquid crystal projector that requires a reduction in thickness, it may not be able to be accommodated in a narrow housing.

[0009] In view of the above-mentioned problems, the present applicant has previously proposed a liquid crystal projector device that is reduced in size (see Japanese Patent Application No. 11-93148).

The liquid crystal projector proposed by the applicant will be described. The above-described projector is used, for example, as a projection unit of a rear projection type projector device.

As shown in FIG. 4, the rear projection type projector device includes a housing 91, a projection unit 92 disposed on the bottom surface of the housing 91, and a reflection mirror 93 disposed on the rear surface at an angle. , And a screen 94 disposed on the front side. Then, the projection optical system 6 of the projection unit 92
Is reflected by a reflection mirror 93 and then projected on a screen 94.

As shown in FIG. 6, a projection unit 92 proposed in Japanese Patent Application No. 11-93148 has a light source unit 1, a color separation unit 2, a GB conversion unit 3, an R modulation unit 4, a color synthesis unit. 5
And a projection optical system 6 including a projection lens.

The light source unit 1 includes a lamp 11a and a reflector 1
A light source 11 made of 1b and a polarizing plate 12 are provided.
The polarizing plate 12 transmits only the P-polarized light component of the white light emitted from the lamp 11.

The color separation section 2 includes a color separation PBS 21, a narrow band phase difference plate 22 for a red component, which is disposed opposite to the main surface of the color separation PBS 21 on the light source section 1 side, and a GB modulation section 3 described later. And a narrow band phase difference plate for blue component 23 disposed on the main surface on the unit side. The color-separating PBS 21 reflects the S-polarized component in the direction of 90 degrees with respect to the incident light on the polarization splitting surface, and transmits the P-polarized component.
The red component narrow band retarder 22 transmits the incident light by rotating the polarization direction of the red component of the incident light by 90 degrees, and transmits the other color components as they are. Similarly, the narrow band phase difference plate for blue component 23 transmits the incident light by rotating the polarization direction of the blue component by 90 degrees and transmits the other color components as they are.

The GB modulation section 3 includes a GB PBS 31 and a blue component liquid crystal panel 32 and a green component liquid crystal panel 33 disposed on two main surfaces adjacent to the GB PBS 31. The PBS 31 for GB is the PBS 2 for color separation.
As in the case of No. 1, the S-polarized light component reflects the S-polarized light component in the direction of 90 degrees with respect to the incident light and transmits the P-polarized light component. The blue component liquid crystal panel 32 and the green component liquid crystal panel 33 are both reflective liquid crystal panels, and rotate the polarization direction of light incident on a pixel to be displayed by 90 degrees based on image information of each color component. In addition to reflecting light, the light incident on the other pixels is reflected as it is.

The R modulating unit 4 includes an R PBS 41 and a red component liquid crystal panel 42 disposed on one main surface of the R PBS 41. PBS 41 for R is PB for color separation
This is the same configuration as S21. Liquid crystal panel 42 for red component
Is a reflection type liquid crystal panel, which changes the polarization direction of light incident on a pixel to be displayed based on the red component image information by 9
The light is reflected by being rotated by 0 degrees, and the light incident on the other pixels is reflected as it is.

The color synthesizing unit 5 includes a color synthesizing PBS 51 and a blue component narrow band phase difference plate 52 that is disposed opposite to the main surface of the PBS 51 on the GB modulation unit 3 side.

In such a configuration, when white light is emitted from the light source 11 of the light source unit 1, only the P-polarized light component of the white light passes through the polarizing plate 12 and is incident on the separation unit 2. .

In the color separation unit 2, the polarization direction of the red component of the P-polarized white light is rotated by 90 degrees by the red component narrow band retardation plate 22, that is, converted to S-polarized light,
It is incident on S21. In the color separation PBS 21, the red component of the S-polarized light is reflected by the polarization separation surface and
At the same time, the blue component and the green component of the P-polarized light pass through and enter the narrow band phase difference plate for blue component 23.

In the narrow band phase difference plate 23 for blue component, the blue component of p-polarized light is converted into s-polarized light, and is incident on the GB modulator 3 together with the green component of p-polarized light.

In the GB modulation section 3, the blue component of S-polarized light is reflected by the polarization splitting surface of the PBS 31 for GB and is incident on the liquid crystal panel 32 for blue component. Liquid crystal panel 3 for blue component
In 2, the polarization direction of the light incident on the pixel to be displayed is rotated by 90 degrees based on the image information of the blue component, that is, P
The light is converted into polarized light and reflected, and light incident on other pixels is reflected as S-polarized light. The remaining green component of the P-polarized light passes through the polarization splitting surface of the PBS 31 for GB and is incident on the liquid crystal panel 33 for the green component. In the green component liquid crystal panel 33, the polarization direction of the light incident on the pixel to be displayed is rotated by 90 degrees based on the green component image information, that is, converted into S-polarized light and reflected, and the other pixels are reflected. Is reflected as P-polarized light.

Then, the P-polarized blue image light reflected by the blue component liquid crystal panel 32 and the S-polarized green image light reflected by the green component liquid crystal panel 33 are again converted into GB.
And is synthesized by the polarization splitting surface. At this time, the P-polarized blue image light passes through the polarization splitting surface, and the S-polarized green image light is reflected by the polarization splitting surface and both enter the color combining unit 5.

On the other hand, the red component of the S-polarized light separated by the color separation unit 2 and incident on the R modulation unit 4 is reflected by the polarization separation surface of the PBS 41 for R and incident on the liquid crystal panel 42 for red component. . In the red component liquid crystal panel 42, the polarization direction of the light incident on the pixel to be displayed is rotated by 90 degrees based on the image information of the red component, that is, the light is converted into P-polarized light and reflected. The P-polarized red image light incident on the R PBS 41 is again incident on the R PBS 41. And
The P-polarized red image light passes through the polarization splitting surface and is incident on the color synthesizing unit 5.

In the color synthesizing unit 5, the polarization direction of the P-polarized blue image light emitted from the GB modulation unit 3 is rotated by 90 degrees by the blue component narrow band phase plate 52, that is, converted into S-polarized light. , And S-polarized green image light are incident on one main surface of the color synthesizing PBS 51. The P-polarized red image light emitted from the G modulating unit 4 is incident on the main surface of the color combining PBS 51 orthogonal to the S-polarized blue image light and green image light incident surfaces.

The S-polarized blue image light and green image light and the P-polarized red image light are combined on the polarization splitting surface of the color combining PBS 51 to become color image light.

The color image light is enlarged and projected on a screen 94 via a reflection mirror 93 via a projection optical system 6.

Thus, according to this example, the PB for GB
Since S31 is used for color separation of the green component and the blue component and for color synthesis of the green image light and the blue image light, an extra light path is provided by using a dichroic mirror or a total reflection mirror for color separation. There is no need to wrap around, and the device can be downsized.

Next, the configuration of a projection unit in another example proposed in Japanese Patent Application No. 11-93148 will be described below.

As shown in FIG. 7, the projection unit in this example is a color separation PBS 21 and a red component narrow band retarder 22 in the projection unit shown in FIG.
Instead of using a first dichroic beam splitter 21a having a dichroic surface that reflects a red component and transmits a green component and a blue component, a color combining PBS 51 and a narrow band phase difference plate 52 for a blue component are used. Instead, the first dichroic beam splitter 21a
Second dichroic beam splitter 5 having the same characteristics as
1a.

According to this example, in addition to miniaturization of the device,
Since the number of parts can be reduced, manufacturing becomes easy.

Further, a color separation PBS 21 and a color synthesis PB are used.
By using a dichroic beam splitter instead of S51, higher luminance can be achieved. The reason will be described below.

FIG. 8 is a diagram showing the wavelength characteristics of the deflection beam splitter, and FIG. 9 is a diagram showing the wavelength characteristics of the dichroic surface. As shown in FIG. 8, the transmittance of the P-polarized light is about 0.82 to 0.85, and the reflectance of the S-polarized light is about 0.99. As shown in FIG. 9, the transmission efficiency on the dichroic surface is 0.99.
About 0.98. As can be seen from this characteristic, by using a dichroic beam splitter instead of the color separation PBS 21 and the color synthesis PBS 51, the transmission of P-polarized light, whose transmission efficiency is reduced, is reduced from twice to once, and the transmission efficiency is reduced. By transmitting a good dichroic surface twice, light use efficiency can be increased. As a result, higher luminance can be achieved.

As shown in FIG. 10, the first and second dichroic beam splitters 21a, 51a
May be first and second dichroic mirrors 21b and 51b having a dichroic surface that reflects a red component and transmits a green component and a blue component. Further, the first and second dichroic mirrors 21b and 51b may be constituted by one sheet.

Further, the PBS used in each of the above examples was used.
Means the remaining four surfaces excluding the two surfaces including the junction of the polarization splitting surfaces.

[0035]

SUMMARY OF THE INVENTION As shown in FIGS.
Although the liquid crystal projector shown in FIG. 10 can be downsized,
It is necessary to assemble a plurality of parts with high accuracy.

An object of the present invention is to achieve easy and accurate assembly, and to achieve lower cost, higher luminance, and higher accuracy.

According to the present invention, there is provided a liquid crystal projector, comprising: a light source for emitting light in a predetermined polarization direction; a polarization separation surface for transmitting a P-polarized component and reflecting an S-polarized component; A prism portion formed by intersecting a dichroic surface that reflects the components and transmits the second and third color components, and first, second, and third components that modulate the light components of the three colors, respectively.
A third reflection type light modulation element, and a projection optical system for enlarging and projecting light obtained by combining the respective color components, wherein light emitted from the light source unit is made incident on a dichroic surface of the prism unit,
The two separated lights are emitted in a direction orthogonal to each other as a first separated light containing a first color component of the three primary colors and a second separated light containing the second and third color components, and The second separated light is polarized by the narrow-band retardation plate into second and third color components having different polarization directions, and the first separated light is disposed on a main surface to which the first separated light reaches. The first color component reflected by the first reflection-type light modulation element and reflected by the first reflection-type light modulation element is projected onto a dichroic surface for synthesizing light of each color component from the polarization splitting surface. And a second color component of the second separated light is a second color component.
Is provided to a second reflection type light modulation element disposed on the main surface to reach the second reflection type light modulation element, and the second color component reflected by the second reflection type light modulation element is output from the polarization separation surface to each color component. A third dichroic surface for synthesizing light is given to the projection optical system, and a third color component of the second separated light is a third reflection type component arranged on a main surface to which the third color component reaches. The third color component reflected by the third reflection type light modulation device is supplied to the projection optical system from the polarization splitting surface through a dichroic surface for synthesizing light of each color component. The combined light combined on the dichroic surface is enlarged and projected from a projection optical system.

The narrow band phase difference plate can be provided in a prism located on the light incident side of the light source.

Further, the narrow band phase difference plate can be provided on a dichroic surface of the prism portion.

According to the above-described structure, by forming the dichroic surface and the polarization splitting surface in the prism section so as to cross each other, the four polarization beam splitters can be replaced with one prism. For this reason, the number of optical components and the angle adjustment of the polarization splitting surface become unnecessary, and the assembling workability is extremely improved and the accuracy is also improved. In addition, high luminance can be achieved by changing from a polarization separation plane having poor separation characteristics to a dichroic plane.

BEST MODE FOR CARRYING OUT THE INVENTION

The structure of the liquid crystal projector according to the first embodiment of the present invention will be described below. In the following description, a case will be described in which the present invention is applied to a projection unit of a rear projection type projector device shown in FIG.

As shown in FIG. 4, the rear projection type projector device according to this embodiment includes a housing 91, a projection unit 92 disposed on the bottom surface of the housing 91, And a screen 94 arranged on the front side. Then, the image light emitted from the projection optical system 6 of the projection unit 92 is reflected on a reflection mirror 93 and then projected on a screen 94.

The projection unit 92 in this embodiment is
As shown in FIG. 1, the light source unit 1 includes a light source unit 1, a prism unit 8, and a projection optical system 6 including a projection lens. The prism section 8 intersects a dichroic surface 8a that reflects a red component and transmits a green component and a blue component, and a deflection separation surface (hereinafter, referred to as a PBS surface) 8b that transmits a P deflection component and reflects an S deflection component. It is formed. Part (8a1) of the dichroic surface 8a of the prism unit 8 serves as the color separation unit 2, and part (8b1, 8b2) of the PBS surface 8b serves as G.
The B conversion unit 3 and the R modulation unit 4 and a part (8a2) of the dichroic surface 8a constitutes the color synthesis unit 5, respectively.

The prism section 8 is prepared, for example, by preparing two dichroic surfaces 8a on one surface of a triangular prism and two PBS surfaces 8b on one surface of a triangular prism. Are formed integrally so as to intersect.

The light source unit 1 includes a lamp 11a and a reflector 1
A light source 11 made of 1b and a polarizing plate 12a are provided. The polarizing plate 12a transmits only the S-polarized light component of the white light emitted from the lamp 11.

As described above, the color separation unit 2 includes the dichroic surface 8a1 of the color separation prism unit 8 and the green component for the green component disposed opposite to the main surface of the color separation dichroic surface 8a1 on the light source unit 1 side. And a narrow band retardation plate 22a. The color separating dichroic surface 8a1 reflects the incident light of the red component in the direction of 90 degrees on the dichroic surface 8a1 and transmits the blue light component and the green light component.

The green component narrow band phase difference plate 22a transmits the incident light by rotating the polarization direction of the green component by 90 degrees and transmits the other color components as they are.

The GB modulation section 3 has a GB PBS surface 8b1.
And a blue component liquid crystal panel 32 and a green component liquid crystal panel 33 disposed on two main surfaces adjacent to the GB PBS surface 8b1. The GB PBS surface 8b1 reflects the S-polarized component in the direction of 90 degrees with respect to the incident light and transmits the P-polarized component. The blue component liquid crystal panel 32 and the green component liquid crystal panel 33 are both reflective liquid crystal panels, and determine the polarization direction of light incident on a pixel to be displayed based on the image information of each color component.
The light is reflected by being rotated by 0 degrees, and the light incident on the other pixels is reflected as it is.

The R modulation section 4 includes an R PBS surface 8b2 and a red component liquid crystal panel 42 disposed on one main surface of the R PBS surface 8b2. Liquid crystal panel 4 for red component
Reference numeral 2 denotes a reflection type liquid crystal panel, which reflects the light incident on the pixel to be displayed based on the image information of the red component by rotating the polarization direction of the light by 90 degrees and reflecting the light on the other pixels. Is reflected as it is.

The color synthesizing section 5 has a color synthesizing dichroic surface 8a2.

In such a configuration, when white light is emitted from the light source 11 of the light source unit 1, only the S-polarized light component of the white light is transmitted through the polarizing plate 12a and enters the color separation unit 2. You.

In the color separation section 2, the polarization direction of the green component of the P-polarized white light is rotated by 90 degrees by the green component narrow-band retardation plate 22a, that is, converted to P-polarized light, and the color-separated dichroic surface. 8a1. On the dichroic surface 8a1, the red component is reflected and incident on the R modulation unit 4, and the blue component and the green component are transmitted and incident on the GB modulation unit 3.

In the GB modulation section 3, the PBS surface 8b1 for GB is used.
The blue component of the S-polarized light is reflected and enters the liquid crystal panel 32 for blue component. In the blue component liquid crystal panel 32,
The polarization direction of the light incident on the pixel to be displayed is rotated by 90 degrees based on the image information of the blue component, that is, converted into P-polarized light and reflected, and the light incident on the other pixels is converted into S-polarized light. Reflect as it is. The remaining green component of the P-polarized light is transmitted through the polarization splitting surface of the GB PBS surface 8b1 and is incident on the green component liquid crystal panel 33. In the green component liquid crystal panel 33, the polarization direction of the light incident on the pixel to be displayed is rotated by 90 degrees based on the green component image information, that is, converted into S-polarized light and reflected, and the other pixels are reflected. Is reflected as P-polarized light.

Then, the P-polarized blue image light reflected by the blue component liquid crystal panel 32 and the S-polarized green image light reflected by the green component liquid crystal panel 33 are again converted into GB.
The light is incident on the PBS surface 8b1 and is combined at the polarization separation surface. At this time, the P-polarized blue image light is transmitted through the polarization separation surface, the S-polarized green image light is reflected by the polarization separation surface,
Both are incident on the color synthesis section 5.

On the other hand, the red component of the S-polarized light separated by the color separation unit 2 and incident on the R modulation unit 4 is converted to the R PBS surface 8b2.
Liquid crystal panel 42 for the red component reflected by the polarization separation surface of
Is incident on. In the red component liquid crystal panel 42, the polarization direction of the light incident on the pixel to be displayed is rotated by 90 degrees based on the image information of the red component, that is, the light is converted into P-polarized light and reflected. The P-polarized red image light incident on the R PBS surface 8b2 is incident again.
Then, the P-polarized red image light passes through the polarization splitting surface and is incident on the color synthesizing unit 5.

In the color synthesizing section 5, the P-polarized blue image light emitted from the GB modulating section 3 is incident on one main surface of the color synthesizing dichroic surface 8a2 together with the S-polarized green image light.
The P-polarized red image light emitted from the G modulating unit 4 is incident on a main surface where the color combining dichroic surface 8a2 is orthogonal to the incident surfaces of the blue image light and the green image light.

Then, the S-polarized blue image light, the P-polarized green image light, and the S-polarized red image light are combined on the color synthesizing dichroic surface to become color image light.

This color image light is enlarged and projected on a screen 94 via a reflection mirror 93 via a projection optical system 6.

As described above, according to this embodiment, the prism portion 8 is formed by crossing the dichroic surface 8a (8a1, 8a2) and the PBS surface 8b (8b1, 8b2), thereby obtaining the structure shown in FIG. , The number of narrow-band phase plates can be reduced, and four PBSs can be replaced with one prism. This eliminates the need for reducing the number of optical components and adjusting the angle of the PBS surface, thereby significantly improving the workability of assembly and improving the accuracy. In addition, high brightness can be achieved by changing the PBS surface having poor separation characteristics to a dichroic surface and reducing the number of narrow band phase plates.

Next, the configuration of the projection unit according to the second embodiment of the present invention will be described below.

In the projection unit of the first embodiment shown in FIG. 1, the narrow band phase difference plate 22a for green component is provided on the light source unit 11 side of the prism unit 8;
As shown in, the projection unit in the present embodiment
As shown in FIG. 2, the dichroic surface 9 of the prism portion 9
A narrow band phase difference plate 9c for green component is provided on a. Since the phase difference plate that rotates the polarization direction only for the selected wavelength does not depend on the incident angle of light, it can be arranged at a 45-degree plane with respect to the incident angle of light on the dichroic surface 9a.

The prism section 9 includes, for example, a dichroic surface 9a formed on one surface of a triangular prism and a PBS surface 9b formed on the other surface, and a dichroic surface 9b formed on one surface of a triangular prism.
After preparing the substrate a, the two are integrated so that the PBS surface 9b is positioned in a direction perpendicular to the dichroic surface 9a, and a narrow band phase difference plate 9c for green component is provided on the dichroic surface 9a. Then, a PBS surface 9 is placed on one side of the triangular prism.
One having b formed and one having a triangular prism are prepared and integrated. Dichroic surface 8a and PBS surface 8b
Are further integrated so that the prism portions 9 intersect with each other.

The dichroic surface 9a1 for color separation is 90% of incident light of the red component on the dichroic surface 9a1.
The light is reflected in the direction of degrees and transmits the blue light component and the green light component.

The green component narrow band phase difference plate 9c transmits the incident light by rotating the polarization direction of the green component by 90 degrees and transmits the other color components as they are.

The PBS surface 9b reflects the S-polarized component in the direction of 90 degrees with respect to the incident light and transmits the P-polarized component. The color synthesizing section 5 includes a color synthesizing dichroic surface 9a2.

In such a configuration, when white light is emitted from the light source 11 of the light source unit 1, only the S-polarized component of the white light is transmitted through the polarizing plate 12a and enters the color separation unit 2. You.

In the color separation section 2, the dichroic surface 9a1
Then, the red component is reflected and enters the R modulation unit 4. The blue component and the green component transmitted through the dichroic surface 9a1 are rotated by 90 degrees in the polarization direction of the green component of the P-polarized white light by the narrow band phase difference plate 9c for green component, that is, converted into P-polarized light. The light enters the modulation unit 3.

In the GB modulation section 3, the PBS surface 9b1 for GB is used.
The blue component of the S-polarized light is reflected and enters the liquid crystal panel 32 for blue component. In the blue component liquid crystal panel 32,
The polarization direction of the light incident on the pixel to be displayed is rotated by 90 degrees based on the image information of the blue component, that is, converted into P-polarized light and reflected, and the light incident on the other pixels is converted into S-polarized light. Reflect as it is. The remaining green component of the P-polarized light is transmitted through the polarization splitting surface of the GB PBS surface 8b1 and is incident on the green component liquid crystal panel 33. In the green component liquid crystal panel 33, the polarization direction of the light incident on the pixel to be displayed is rotated by 90 degrees based on the green component image information, that is, converted into S-polarized light and reflected, and the other pixels are reflected. Is reflected as P-polarized light.

Then, the P-polarized blue image light reflected by the blue component liquid crystal panel 32 and the S-polarized green image light reflected by the green component liquid crystal panel 33 are again converted into GB.
The light is incident on the PBS surface 9b1 and is combined at the polarization splitting surface. At this time, the P-polarized blue image light is transmitted through the polarization separation surface, and the S-polarized green image light is reflected by the polarization separation surface. Then, the polarization direction of the green component of the S-polarized light is rotated by 90 degrees by the green-component narrow-band phase difference plate 9 c, that is, converted into P-polarized light and incident on the color combining unit 5.

On the other hand, the red component of the S-polarized light separated by the color separation unit 2 and incident on the R modulation unit 4 is converted into the R PBS surface 9b2.
Liquid crystal panel 42 for the red component reflected by the polarization separation surface of
Is incident on. In the red component liquid crystal panel 42, the polarization direction of the light incident on the pixel to be displayed is rotated by 90 degrees based on the image information of the red component, that is, the light is converted into P-polarized light and reflected. Is again incident on the R PBS surface 9b2.
Then, the P-polarized red image light passes through the polarization splitting surface 9b2 and is incident on the color combining unit 5.

In the color synthesizing unit 5, the P-polarized blue image light emitted from the GB modulating unit 3 is converted into a narrow band phase difference plate 9 for green component.
The light is incident on one principal surface of the color synthesizing dichroic surface 9a2 together with the green image light deflected to P-polarized light at c. Further, the P-polarized red image light emitted from the G modulating unit 4 is incident on a main surface of the color synthesizing dichroic surface 9a2 orthogonal to the incident surfaces of the blue image light and the green image light.

Then, the P-polarized blue image light, the green image light, and the red image light are combined with the color synthesizing dichroic surface 9a2.
Are combined into a color image light. The color image light is enlarged and projected on the screen 94 via the reflection mirror 93 via the projection optical system 6.

As described above, according to this embodiment, the prism part 9 is formed by crossing the dichroic surfaces 9a (9a1, 9a2) and the PBS surfaces 9b (9b1, 9b2), thereby reducing the number of optical components and reducing the PBS. It is not necessary to adjust the angle of the surface, so that the assembling workability is extremely improved and the accuracy is also improved. In addition, high luminance can be achieved by changing from a PBS surface having poor separation characteristics to a dichroic surface.

Next, a third embodiment of the present invention will be described with reference to FIG. The embodiment shown in FIG.
A narrow band phase difference plate 8c for red component is provided on the emission side of the light. With the narrow band phase difference plate 8c for red component,
The S-polarized red image light becomes a P-polarized red image light, and all the P-polarized image light is supplied to the projection optical system 6. Further, the type of the phase difference plate can be changed so that the image light of the S-deflected light is all provided.

In each of the above embodiments, the present invention is applied to the projection unit 92 of the rear projection type projector.
Has been described, but the present invention may be applied to a front-type projector device.

FIG. 5 is a schematic diagram showing an example in which the projection unit of the present invention is used in a three-dimensional image display device. In this three-dimensional image display device, as described above, the type of the phase difference plate is changed so that one projection unit 92a emits S-polarized light image light and the other projection unit 92b emits P-polarized light. Use something. These two projection units 92
a, the image light from 92b is condensed on the screen 94a. Then, a left-eye image is given to one of the projection units 92a and 92b, and a right-eye image is given to the other. The observer can observe a stereoscopic image by putting on the polarizing glasses 95.

[0076]

As described above, according to the present invention, since the prism portion is formed by crossing the dichroic surface and the PBS surface, the number of optical components and the angle adjustment of the PBS surface become unnecessary, and assembling is performed. The workability is extremely improved, and the accuracy is also improved. In addition, P having poor separation characteristics
High luminance can be achieved by changing from the BS surface to the dichroic surface.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a projection unit mounted on a rear projection type liquid crystal projector according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating a projection unit mounted on a rear projection type liquid crystal projector according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram illustrating a projection unit mounted on a rear projection type liquid crystal projector according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram showing a rear projection type liquid crystal projector to which the present invention is applied.

FIG. 5 is a schematic diagram showing a configuration in which the present invention is applied to a stereoscopic video display device.

FIG. 6 is a configuration diagram showing a projection unit mounted on a rear projection type liquid crystal projector as a premise of the present invention.

FIG. 7 is a configuration diagram showing another projection unit mounted on a rear projection type liquid crystal projector as a premise of the present invention.

FIG. 8 is a diagram illustrating wavelength characteristics of a deflection beam splitter.

FIG. 9 is a diagram illustrating wavelength characteristics of a dichroic surface.

FIG. 10 is a configuration diagram showing another projection unit mounted on a rear projection type liquid crystal projector which is a premise of the present invention.

FIG. 11 is a configuration diagram showing another projection unit mounted on a conventional rear projection type liquid crystal projector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light source part 12a Polarizer 8 Prism part 8a Dichroic surface 8b PBS surface Two color separation part 22a Narrow band phase difference plate for red component 3 GB modulation part 4 R modulation part 5 Color synthesis part 6 Projection optical system

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[Procedure amendment]

[Submission date] May 17, 2001 (2001.5.1)
7)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction contents]

An object of the present invention is to achieve easy and accurate assembly, and to achieve lower cost, higher luminance, and higher accuracy.

According to the present invention, there is provided a liquid crystal projector, comprising: a light source for emitting light in a predetermined polarization direction; a polarization separation surface for transmitting a P-polarized component and reflecting an S-polarized component; A prism portion formed by intersecting a dichroic surface that reflects the components and transmits the second and third color components, and first, second, and third components that modulate the light components of the three colors, respectively.
A third reflection type light modulation element, and a projection optical system for enlarging and projecting light obtained by combining the respective color components, wherein light emitted from the light source unit is made incident on a dichroic surface of the prism unit,
The two separated lights are emitted in a direction orthogonal to each other as a first separated light containing a first color component of the three primary colors and a second separated light containing the second and third color components, and The second separated light is polarized by the narrow band retarder into second and third color components having different polarization directions, and the first separated light is disposed on the main surface to which the first separated light reaches. The first color component reflected by the first reflection-type light modulation element and reflected by the first reflection-type light modulation element is projected onto a dichroic surface for synthesizing light of each color component from the polarization splitting surface. And a second color component of the second separated light is a second color component.
Is provided to a second reflection type light modulation element disposed on the main surface to reach the second reflection type light modulation element, and the second color component reflected by the second reflection type light modulation element is output from the polarization separation surface to each color component. A third dichroic surface for synthesizing light is given to the projection optical system, and a third color component of the second separated light is a third reflection type component arranged on a main surface to which the third color component reaches. The third color component reflected by the third reflection type light modulation device is supplied to the projection optical system from the polarization splitting surface through a dichroic surface for synthesizing light of each color component. The combined light combined on the dichroic surface is enlarged and projected from a projection optical system.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0037

[Correction method] Change

[Correction contents]

The narrow- band retardation plate can be provided in a prism located on the light incident side of the light source.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0038

[Correction method] Change

[Correction contents]

Further, the narrow band retarder can be provided on a dichroic surface of the prism portion.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09F 9/00 360 G09F 9/00 360K (72) Inventor Toshio Konagaya 2-5-5 Keihanhondori, Moriguchi-shi, Osaka No. 5 SANYO Electric Co., Ltd. F-term (reference) 2H042 CA08 CA14 CA17 2H088 EA15 EA16 EA18 MA02 MA06 2H091 FA05X FA08X FA11X FA14X FA14Z FA21X FA26X FA26Z FA41X LA12 LA15 LA17 5G435 AA03 AA17 BB12 CC12 BB12 CC LL15

Claims (3)

[Claims] 1. A light source unit for emitting light of a predetermined polarization direction, a polarization separation surface that transmits a P-polarized component and reflects an S-polarized component, and a second and third colors that reflect a first color component. A prism portion formed by intersecting a dichroic surface through which the components pass, and a first portion that modulates the light components of the three colors, respectively.
A projection optical system for enlarging and projecting light obtained by combining the respective color components; and emitting light from the light source unit to a dichroic surface of the prism unit. A first separated light including a first color component of the primary colors;
The two separated lights are emitted in a direction orthogonal to each other as a second separated light including a second and a third color component, and the second separated light is polarized in a second direction having different polarization directions from each other by a narrow band phase difference plate. And the first separated light, which is polarized into a third color component, is provided to a first reflection type light modulation element disposed on a main surface to which the first separation light reaches, and the first reflection type light is The first color component reflected by the modulation element is provided to the projection optical system by a dichroic surface for synthesizing light of each color component from the polarization separation surface, and a second color component of the second separated light is ,
A second color component is provided to a second reflection type light modulation element disposed on the main surface to reach the second color component, and the second color component reflected by the second reflection type light modulation element is converted from the polarization separation surface into each color. The component light is provided to the projection optical system on a dichroic surface for synthesizing the component light, and the third color component of the second separated light is the third color component disposed on the main surface to which the third color component reaches. The third color component provided to the reflection-type light modulation element and reflected by the third reflection-type light modulation element is transmitted from the polarization splitting surface to the projection optical system via a dichroic surface for synthesizing light of each color component. A liquid crystal projector, wherein the combined light provided on the dichroic surface is enlarged and projected from a projection optical system. 2. The liquid crystal projector according to claim 1, wherein the narrow band phase difference plate is provided on a prism located on a light incident side of a light source. 3. The liquid crystal projector according to claim 1, wherein the narrow band phase difference plate is provided on a dichroic surface of a prism unit.