JPH11183865A - Reflection type liquid crystal projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal projector of which cost is reduced by omitting one polarized beam splitter(PBS). SOLUTION: The polarized light components of two optional colors out of beams of three colors R, G, B are allowed to intersect with each other at right angles, reflection type liquid crystal panels 5b, 5g corresponding to the two color beams are respectively arranged on the mutually rectangular faces of the PBS 41 and the polarized light components of two colors intersecting with each other at right angles are made incident upon the same PBS 41. Since the polarized light components of two colors are spectrally processed, respectively modulated by the panels 5b, 5g, converged again, and projected and the beams of two colors can be processed by the same PBS 41, only two PBSs 41, 42 are used by omitting one of three expensive PBSs, so that the cost reduction of the projector can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection type liquid crystal projector, and more particularly to a reflection type liquid crystal projector whose cost is reduced by omitting one expensive PBS (polarizing beam splitter).

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 2, in a reflection type liquid crystal projector, light L emitted from a light source 1 and reflected by a reflector 2 is transmitted through a plurality of dichroic mirrors 3a and 3b to R light Lr and G light Lg. , And B light Lb,
Each of the color lights enters PBSs (polarization beam splitters) 4r, 4g, and 4b corresponding to each color light, and is modulated by a video signal or the like by the reflective liquid crystal panels 5r, 5g, and 5b corresponding to each color light. Each color light emitted from the PBSs 4r, 4g, 4b is condensed via dichroic mirrors 3c, 3d and projected on a screen 7 via a projection lens 6. However, this configuration has a problem that the cost is high because three expensive PBSs (polarization beam splitters) are used for each color light.

[0003]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and provides a reflection type liquid crystal projector in which one of three expensive PBSs (polarization beam splitters) can be omitted to reduce the cost. It is intended to provide.

[0004]

In order to solve the above-mentioned problems, the present invention disperses light emitted from a light source and reflected by a reflector into a predetermined color light through a plurality of dichroic mirrors, and converts each color light into a PBS (PBS). After entering the reflective liquid crystal panel corresponding to each of the R, G, and B color lights via a polarizing beam splitter) and modulating the same with a video signal or the like, each color light emitted from the PBS is collected via a dichroic mirror. In a reflection type liquid crystal projector that emits light and projects it on a screen via a projection lens, two of the three color lights of R, G, and B are used.
While the polarization components of the color lights are orthogonalized, reflective liquid crystal panels corresponding to the same two-color lights are respectively arranged on surfaces of the PBS that are perpendicular to each other, and the orthogonal two-color polarizations are set to the same PBS.
, A reflection type liquid crystal projector capable of processing two colors with the same PBS. Also, the light emitted from the light source and reflected by the reflector is split into three color lights of R light, G light, and B light through a plurality of dichroic mirrors and the like, and one of the three color lights is converted into a λ / 2 phase. After being polarized by 90 degrees through a plate, the reflection type liquid crystal projector is arranged such that the polarization components of the two colors are made orthogonal to each other by guiding the other one color light to the same optical path by a dichroic mirror or the like.

A first dichroic mirror that reflects the B light of the light emitted from the light source and reflected by the reflector, and transmits the R light and the G light to split the light into B light and (R + G) light; (R + G)
A mirror for parallelizing the light, a λ / 2 phase plate for polarizing the B light from the mirror by 90 degrees, and reflecting the split (R + G) light to make a right angle with the 90 degrees polarized B light. Second
And the G light that reflects the R light of the (R + G) light reflected from the second dichroic mirror, transmits the G light, and reflects and transmits the B light from the λ / 2 phase plate. A third dichroic mirror that condenses with light and guides the same to the same optical path; and a first dichroic mirror that receives the condensed B light and G light, transmits the B light, and reflects and separates G light.
A PBS and a reflective liquid crystal panel for B light, which is arranged at right angles to the first PBS, modulates the dispersed B light and G light by a video signal or the like, and polarizes and reflects the light by 90 degrees.
And a reflective liquid crystal panel for G light, and a second PB that transmits R light dispersed by the third dichroic mirror.
S, a reflective liquid crystal panel for R light that modulates the transmitted R light with a video signal or the like, and transmits the modulated B light and G light, and intersects the modulated B light and G light orthogonally. And a fourth dichroic mirror for reflecting the R light, G light and B light which are incident on the screen, and projecting the modulated light from the fourth dichroic mirror onto a screen. And a reflection type liquid crystal projector including a projection lens.

[0006]

As described above, in the reflection type liquid crystal projector of the present invention, the polarization components of the two color lights of the three color lights of R, G, and B are made orthogonal to each other, while the PBS (polarization beam splitter) is made mutually. A reflection type liquid crystal panel corresponding to the same two-color light is disposed on the surface at a right angle, and the orthogonal two-color polarized light is incident on the same PBS, whereby
The polarized light of each color is separated and modulated by each of the reflection type liquid crystal panels, and then condensed again to emit light. Since two colors can be processed by the same PBS, three colors of light can be processed by two PBSs. .

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A reflection type liquid crystal projector according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram showing one embodiment of a reflection type liquid crystal projector according to the present invention. As shown in the figure, B light Lb of light L emitted from the light source 1 and reflected by the reflector 2 is reflected, and R light Lr and G light are reflected.
The first dichroic mirror 31 that transmits the light Lg and splits the light into the B light Lb and the (R + G) light Lr + g
A mirror 32 that reflects the separated B light Lb and makes it parallel to the (R + G) light Lr + g, a λ / 2 phase plate 8 that polarizes the B light Lb from the mirror 30 by 90 degrees, A second dichroic mirror 32 that reflects the (R + G) light Lr + g and forms a right angle with the 90-degree polarized B light Lb, and R of the (R + G) light Lr + g reflected from the second dichroic mirror 32 G reflects light Lr
A third dichroic mirror 33 that transmits the light Lg, reflects the B light Lb from the λ / 2 phase plate 8, condenses the transmitted G light Lg, and guides it to the same optical path; The first PBS 41 that receives the B light Lb and the G light Lg, transmits the B light Lb, reflects the G light Lg, and splits the light.
And a reflection type liquid crystal panel 5b for B light, which is arranged at a right angle to the first PBS 41, modulates the split B light Lb and G light Lg by a video signal or the like, polarizes them 90 degrees, and reflects them. The reflection type liquid crystal panel for light 5g and the R light Lr split by the third dichroic mirror 33
And a reflective liquid crystal panel 5r for R light that modulates the transmitted R light Lr with a video signal or the like.
And the reflected R light Lrm, which transmits the modulated B light Lbm and G light Lgm and reflects the modulated R light Lrm which enters orthogonally with the modulated B light Lbm and G light Lgm. ,
A fourth dichroic mirror 34 for condensing the G light Lgm and the B light Lbm, and a projection lens 6 for projecting the modulated light Lm from the fourth dichroic mirror 34 onto the screen 7 I have.

Next, the operation of the above configuration will be described. The light L emitted from the light source 1 and reflected by the reflector 2 is reflected by the first dichroic mirror 31 at right angles to the B light Lb, and transmitted through the R light Lb and the G light Lg to produce the B light Lb and ( (R + G) light Lr + g, and the separated B light Lb is made parallel to the (R + G) light Lr + g by a mirror 30, and then is transmitted through the λ / 2 phase plate 8 to 90 °.
While being incident on the third dichroic mirror 33 and entering the third dichroic mirror 33, the transmitted (R + G) light Lr + g is bent at a right angle by the second dichroic mirror 32 and is orthogonal to the 90-degree polarized B light Lb. Then, the light enters the third dichroic mirror 33, reflects the 90-degree-polarized B light Lb at a right angle, and transmits the G light Lg to condense both lights, while turning the R light Lr at a right angle. The reflected 90-degree polarized B light Lb and G light Lg enter the first PBS 41 and are dispersed, and are dispersed, and are reflected at right angles to the PBS 41. After being modulated by the panel 5b and the G-light reflective liquid crystal panel 5g, respectively, the light is condensed again and enters the fourth dichroic mirror 34, while
The R light Lr enters the second PBS 42, is modulated by the R light reflective liquid crystal panel 5r, and then modulated by the fourth dichroic mirror 34 to the modulated B light Lbm + G light L.
gm, the R light Lrm, the G light Lgm, and the B light Lbm, which are incident orthogonal to the gm and modulated by the fourth dichroic mirror 34.
Is condensed and projected on the screen 7 via the projection lens 6, whereby a color image can be projected on the screen.

[0009]

As described above, according to the reflection type liquid crystal projector of the present invention, the polarization components of the two color lights out of the three color lights of R, G, and B are made orthogonal to each other, while the PBS (polarization beam splitter) is made mutually. By arranging the reflection type liquid crystal panels corresponding to the same two-color light on the surfaces which are at right angles, and entering the two orthogonally polarized lights into the same PBS,
Two colors of polarized light are separated and modulated by each of the reflection type liquid crystal panels, condensed and emitted again, and the two colors can be processed by the same PBS, so that three expensive PBSs (polarization beam splitters) are used. It is possible to provide a reflection-type liquid crystal projector in which one is omitted and the cost is reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of a reflection type liquid crystal projector according to the present invention.

FIG. 2 is a schematic configuration diagram showing a conventional reflection type liquid crystal projector.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 light source 2 reflector 30 mirror 31 first dichroic mirror 32 second dichroic mirror 33 third dichroic mirror 34 fourth dichroic mirror 41 first PBS 42 second PBS 5b B light reflective liquid crystal panel 5g G Reflective liquid crystal panel for light 5r Reflective liquid crystal panel for R light 6 Projection lens 7 Screen 8 λ / 2 phase plate

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 5/74 H04N 5/74 A 9/31 9/31 C

Claims (3)

[Claims] 1. A light emitted from a light source and reflected by a reflector is split into predetermined color lights through a plurality of dichroic mirrors, and each color light is converted into R, G, and B color lights through a PBS (polarization beam splitter). After entering the reflection type liquid crystal panel corresponding to and modulating with a video signal or the like, each color light emitted from the PBS is condensed through a dichroic mirror,
In a reflection type liquid crystal projector that projects onto a screen via a projection lens, the polarization components of two colors of the three colors of R, G, and B are orthogonalized, and the surfaces of the PBS that are perpendicular to each other correspond to the two colors of light. Reflective liquid crystal panels are arranged, and the two orthogonally polarized lights are polarized by the same PB.
A reflection type liquid crystal projector characterized in that two colors can be processed by the same PBS by entering light into S. 2. A light emitted from a light source and reflected by a reflector is converted into an R light through a plurality of dichroic mirrors or the like.
G light and B light are separated into three color lights, one of the three color lights is polarized by 90 degrees through a λ / 2 phase plate, and then guided to the same light path with another one color light by a dichroic mirror or the like. 2. The reflection type liquid crystal projector according to claim 1, wherein the polarization components of the two colors are orthogonal to each other. 3. A first dichroic mirror that reflects B light of light emitted from a light source and reflected by a reflector, transmits R light and G light, and splits the light into B light and (R + G) light. , The reflected B light is reflected and the (R +
G) A mirror for making the light parallel to the light, and a B light from the mirror for 9 minutes.
A λ / 2 phase plate that polarizes 0 degree, and the separated (R +
G) a second dichroic mirror that reflects light to make a right angle with the 90-degree polarized B light, and R light of (R + G) light reflected from the second dichroic mirror to convert G light. A third dichroic mirror that transmits and reflects the B light from the λ / 2 phase plate, condenses the transmitted G light and guides it to the same optical path; A first PBS that receives the light, transmits the B light, reflects the G light, and disperses the light; and arranges the B light and the G light that are arranged at right angles to the first PBS and separates the B light and the G light according to a video signal or the like. A reflective liquid crystal panel for B light and a reflective liquid crystal panel for G light that are modulated and polarized and reflected by 90 degrees, and a second PBS that transmits the R light dispersed by the third dichroic mirror; A reflective liquid for R light that modulates the transmitted R light with a video signal or the like. The panel transmits the modulated B light and the G light, and reflects the modulated R light that enters at right angles to the modulated B light and the G light to reflect the R light, the G light, and the B light. 2. The device according to claim 1, comprising a fourth dichroic mirror for condensing light, and a projection lens for projecting the modulated light from the fourth dichroic mirror onto a screen.
The reflective liquid crystal projector as described in the above.