JPH10133147A - Liquid crystal projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal projector capable of being lightened in weight without degrading quality of image enlarged/projected onto a screen. SOLUTION: This liquid crystal projector is provided with a first lens array 4 dividing light from a paraboloidal mirror 2 arranging a light source 1 on its focal point to a plurality of luminous flux, a polarizing beam splitter 5 and a half wavelength plate 10b separating respective luminous flux to first, second linear polarization light that polarization directions are orthogonally intersected with each other, and arranging the polarization directions, a second lens array 10 irradiating respective luminous flux of a plurality of small light sources on liquid crystal panels 23-25 and a projection lens 22 enlarging/ projecting optical images by the liquid crystal panels 23-25 on a screen. Then, the polarizing beam splitter 5 is provided with first, second rectangular prisms 5a, 5b, and either planes containing respective emission surfaces of the first, second rectangular prisms 5a, 5b don't traverse respective lens central parts of plural first lenses 4a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal projector for enlarging and projecting an optical image on a screen.

[0002]

2. Description of the Related Art As means for displaying a large image, conventionally, an optical image formed according to a video signal by a liquid crystal panel is illuminated with illumination light, and the optical image illuminated by the illumination light is projected onto a projection lens (projection lens). There is known a liquid crystal projector that performs enlarged projection on a screen.

A configuration diagram of a conventional illumination optical system used in such a liquid crystal projector will be described with reference to FIG. The light beam of the randomly polarized light emitted from the light source 51 is unnecessary wavelength by the IR-UV cut filter 53 together with the light reflected on the reflection surface 52a of the parabolic mirror 52 which is a part including the pole of the paraboloid of revolution. The area is removed.
The light from which the unnecessary wavelength range has been removed is split by the first lens array 54 into a plurality of light beams.

[0004] Each of a plurality of light beams split by the first lens array 54 is converted into a first linearly polarized light beam and a second linearly polarized light beam whose polarization directions are orthogonal to each other by a triangular prism-shaped polarizing beam splitter 55. Separated into a luminous flux.

The plurality of light beams of the first and second linearly polarized light components are respectively formed by the first lens array 54 in the vicinity of the second lens array 56 due to the image forming action of the first lens array 54. The same number of small light sources as the number of the plurality of divided light beams are formed.

[0006] Of the small light sources formed on the second lens array 56, a half-wave plate is provided on the exit side on the second lens array 56 where the small light source formed by the light beam of the second linearly polarized light component is located. By attaching 57, the polarization direction of the second linear polarization component is converted to the polarization direction of the first linear polarization component, and the polarization directions of all the small light sources can be made uniform.

The linearly polarized illumination light emitted from the illumination optical system is radiated to an optical image formed on a liquid crystal panel in accordance with a video signal, and the optical image illuminated by the illumination light is projected. If a lens is enlarged and projected on a screen, a good large image can be displayed.

[0008]

However, in such a conventional liquid crystal projector, the weight of the right angle prism of the polarizing beam splitter 55 is as large as about 700 g, which is one of the factors that hinder the weight reduction of the liquid crystal projector.

An object of the present invention is to provide a liquid crystal projector that can be reduced in weight without deteriorating the quality of an image projected and projected on a screen in consideration of such problems.

[0010]

According to the present invention, there is provided a first lens array having a plurality of two-dimensionally arranged first lenses for dividing light from a light source into a plurality of light beams. And a separating section that separates each of the plurality of incident light beams into first and second linearly polarized light beams whose polarization directions are orthogonal to each other by reflecting the light beams on a 45-degree inclined surface, and the first and second linear light beams. A polarization conversion optical system having a conversion unit for converting one polarization direction of the linearly polarized light into the other polarization direction, and the plurality of first and second linearly polarized lights near where the first or second linearly polarized light converges. A second lens having a plurality of second lenses arranged two-dimensionally corresponding to the linearly polarized light, and wherein the conversion unit is disposed on an incident surface or an exit surface side of the plurality of second lenses. LCD projectors equipped with an illumination optical system consisting of a lens array The separating unit is formed by continuously arranging a plurality of triangular prism-shaped right angle prisms such that the slopes form the same surface, and among the planes including the exit surfaces of the plurality of right angle prisms, A plane crossing the first lens array is a liquid crystal projector that crosses a boundary located between the first lenses adjacent to each other.

[0011] Of the planes including the entrance surfaces of the plurality of right-angle prisms, a plane crossing the second lens array may cross a boundary located between the adjacent second lenses. Good.

[0012] In the present invention having the above-described structure, the light-weighted polarization conversion optical system may be configured such that the image in which the ridge line of the right-angle prism of the conversion unit is blurred is not projected onto the screen, and the first lens array is not used. Are separated into first and second linearly polarized light beams whose polarization directions are orthogonal to each other, and the polarization direction of one or all of the first and second linearly polarized light beams is changed to the other polarization direction. Convert to direction.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram showing a first embodiment of the present invention. The light source 1 is a metal halide lamp that emits randomly polarized white light. The parabolic mirror 2 has a reflecting surface 2a whose section is axisymmetrically formed on a part of the surface including the poles of the paraboloid of revolution, and has a focal point (the light source 1 is installed at this focal point position). ) Is a mirror that reflects the light radiated from the opening 2b to the outside of the opening 2b (to the right in FIG. 1). I
The R-UV cut filter 3 is a filter arranged in the vicinity of the opening 2b. The R-UV cut filter 3 has a wavelength range that is unnecessary for the light of the three primary colors from the direct light from the light source 1 and the reflected light from the reflecting surface 2a. Remove light. The first lens array 4 constituting the optical integrator is a lens array having a plurality of first lenses 4a two-dimensionally arranged, and removes light in a wavelength range that is unnecessary for light of three primary colors. The direct light from the light source 1 and the reflected light from the reflecting surface 2a of the parabolic mirror 2 are incident, split into a plurality of light beams, and emitted. The aperture shapes of the plurality of first lenses 4a are the same. Note that the first lens array 4 is arranged near the output side of the IR-UV cut filter 3 so as to be closer to the parabolic mirror 2.

The polarizing beam splitter 5 includes first and second right-angle prisms 5a and 5 made of triangular prism transparent glass or the like.
b, etc., which is a separation part of the polarization conversion optical system, wherein the rear surface, which is the inclined surface, is disposed so as to form an angle of 45 degrees with the optical axis of the first lens array 4, and is divided by the first lens array 4. Each of the plurality of luminous fluxes is optically separated into a luminous flux 6 of a first linearly polarized light component and a luminous flux 7 of a second linearly polarized light component, whose polarization directions are orthogonal to each other. On each of the inclined rear surfaces of the first and second right-angle prisms 5a and 5b, a polarization separation surface 5d is formed, and a first linearly polarized light component of the light incident from the first lens array 4 is formed. Are reflected perpendicularly to the incident angle of 45 degrees on the polarization separation surface 5d, and the luminous flux 6
Inject as The total reflection surface 5f is formed so as to face the polarization separation surface 5d at an interval of a thickness 5e from the polarization separation surface 5d,
A second linearly polarized light component orthogonal to the first linearly polarized light component of the light incident from the first lens array 4 is reflected by the total reflection surface 5f at a right angle to the incident angle of 45 degrees, The light is emitted as a light flux 7. The dimension of the thickness 5e is set based on the pitch at which the light flux 6 and the light flux 7 are emitted ( ^21/2 times the thickness 5e) and the pitch of the second lens 10a.

FIG. 2A is a perspective view of the polarization beam splitter 5, and FIG. 2B is a plan view including the polarization beam splitter 5, the first lens array 4, the second lens array 10, and the like. Shown in In FIG. 2A, the entrance plane and the exit plane of each of the first and second right-angle prisms 5a and 5b are planes A1 and A2 and planes B1 and B2, respectively. This is obtained by substantially removing the rectangular parallelepiped portion having the surface B1 and the surface A2.

In FIG. 2B, the entrance surface A1 of the first right-angle prism 5a faces the lower side of the exit surface of the first lens array 4, and the entrance surface A2 of the second right-angle prism 5b.
Is opposed to the upper side of the exit surface of the first lens array 4. The first right-angle prism 5a has a boundary 4b whose plane including the exit surface B1 is located between the first lens 4a of the second stage and the first lens 4a of the third stage from the top. It is arranged to cross. Thereby, the emission surface B
Since the plane including 1 does not cross the center of the first lens 4a, it is possible to reliably prevent the blurred image of the ridge line C from being projected onto a screen (not shown).

The second lens array 10 constituting the optical integrator is two-dimensionally arranged in the vicinity where the plurality of light beams 6 and 7 separated by the light beam splitter 5 converge, and the plurality of light beams 6 and the plurality of light beams Is a lens array having the same number of second lenses 10 a as the number of light beams 7. That is, the second lens array 10 has twice as many lenses as the plurality of first lenses 4a of the first lens array 4, and each of the two lenses adjacent to each other in the left-right direction in FIG.
The second lenses 10a correspond to each one of the first lenses 4a. A part of the exit surface of the second lens array 10 from which the light beam 7 is emitted is provided for converting the second linearly polarized light of the light beam 7 into the same polarization direction as the first linearly polarized light of the light beam 6. A half-wave plate 10b is provided. The half-wave plate 10b is a conversion unit of the polarization conversion optical system, and forms a polarization conversion optical system together with the polarization beam splitter 5 described above.

The liquid crystal panel 23 is a transmission type liquid crystal panel, and forms an optical image of B of RGB. The liquid crystal panel 24 is a transmissive liquid crystal panel, and G of RGB
To form an optical image. The liquid crystal panel 25 is a transmissive liquid crystal panel, and forms an optical image of R of RGB.

The color separating means for separating each of the three primary colors for illuminating each of the three liquid crystal panels 23 to 25 with light of the corresponding primary color is composed of a dichroic filter 11 and a dichroic filter 12. The dichroic filter 11 has a cutoff value of a wavelength of 510 nm, reflects a light beam in the B wavelength band, and transmits a light beam in the R and G wavelength bands. The total reflection mirror 13 directs the separated light beam in the B wavelength band toward the liquid crystal panel 23. The field lens 14 is a total reflection mirror 1
This is for irradiating the liquid crystal panel 23 with the luminous flux of the wavelength band of B reflected by 3. Dichroic filter 1
Reference numeral 2 has a cutoff value of a wavelength of 580 nm, and reflects a light beam in the G wavelength band among light beams in the R and G wavelength bands transmitted through the dichroic filter 11, and transmits a light beam in the R wavelength band. The field lens 15 is for irradiating the liquid crystal panel 24 with the light flux in the G wavelength band separated by the dichroic filter 12. Lens 19,
The 20 and the total reflection mirrors 17 and 18 constitute a relay optical system for guiding a light beam in the R wavelength band transmitted through the dichroic filter 12 to the liquid crystal panel 25 while maintaining its illuminance. This is for irradiating the liquid crystal panel 25 with a light beam in the R wavelength band guided by the optical system.

The dichroic prism 21 is formed by joining four right-angle prisms so as to form a cube or a rectangular parallelepiped, and a dichroic mirror portion is formed on the joint surface. The dichroic prism 21 is formed by three liquid crystal panels 23 to 25. The optical images of the respective RGB colors are combined.

The projection lens 22 is a projection optical system for enlarging and projecting the color optical image synthesized by the dichroic prism 21 on a screen.

Next, the operation of the present embodiment will be described.

The randomly polarized light beam emitted from the light source 1 is reflected by the reflecting surface 2a of the parabolic mirror 2 together with the reflected light by the IR-UV cut filter 3 so as to be unnecessary for the three wavelength bands of RGB. Is removed. The light from which the unnecessary wavelength band has been removed is split into a plurality of light beams by the first lens array 4.

Each of the plurality of light beams split by the first lens array 4 is converted by a polarizing beam splitter 5 into a first linearly polarized light beam 6 and a second linearly polarized light beam whose polarization directions are orthogonal to each other. 7 is separated. That is, the light beam coming from the exit surface of the first lens array 4 passes through the polarization beam splitter 5 straight as incident light. At this time, the exit surfaces B1 of the first right-angle prisms 5a and 5b
Coincides with the boundary 4b of the plurality of first lenses 4a, so that the blurred image of the ridge line C is not projected on the screen. The first linearly polarized light component of the incident light that passes straight through the polarization beam splitter 5 is reflected at a right angle by the polarization splitting surface 5 d and exits as a light beam 6. Also, the incident light of the second linearly polarized light component, which is transmitted through the optical path 8 due to the thickness 5e and travels straight without being reflected by the polarization splitting surface 5d, is reflected by the total reflection surface 5f at right angles to the incident angle of 45 degrees. Then, the light is emitted as a light flux 7.

Each of the plurality of light beams 6 and the plurality of light beams 7 is divided by the first lens array 4 in the vicinity of the second lens array 10 by the image forming action of the first lens array 4. The same number of small light sources as the number of light beams are formed. At this time, the small light source formed by the light beam 7 is equal to the small light source formed by the light beam 6 in a direction in which the light beam 7 travels straight along the optical path 8 due to the thickness 5e of the polarization separation surface 5d and the total reflection surface 5f. An image is formed with a lateral shift amount 9. The thickness 5e of the polarization splitting surface 5d and the total reflection surface 5f is set such that the lateral shift amount 9 is equal to half of the interval between the small light sources formed by the plurality of light fluxes 6. As a result, in the vicinity of the second lens array 10, the light flux 6
And the small light source by the light beam 7 appear alternately.
The total number of the small light sources is the sum of the small light sources formed by the plurality of light beams 6 and the small light sources formed by the plurality of light beams 7. This total number is equal to twice the number of the plurality of light beams divided by the first lens array 4. The area occupied by the small light source (hereinafter, referred to as a secondary light source) formed by the plurality of light beams 6 and the plurality of light beams 7 on the second lens array 10 is such that the small light source formed by the plurality of light beams 6 is the second lens array. The area occupied on the area 10 is substantially the same as the area occupied by the area 10, and the limited space can be effectively used because of its high density.

By attaching a half-wave plate 10b to the exit surface of the second lens 10a where the small light source formed by the light beam 7 among the secondary light sources formed on the second lens array 10 is located, The polarization direction of the second linearly polarized light component 7 is converted to the polarization direction of the first linearly polarized light component of the light beam 6, and the polarization directions of all the small light sources can be made uniform. Thus, the light beams emitted from all the small light sources in the secondary light source can be used for illuminating each of the three liquid crystal panels 23 to 25.

A plurality of luminous fluxes guided to the second lens array 10 are subjected to Rch by dichroic filters 11 and 12.
It is separated into three wavelength bands of GB. That is, the luminous flux in the wavelength band of B separated by the dichroic filter 11 is reflected by the total reflection mirror 13 and passes through the field lens 14, and then illuminates the liquid crystal panel 23. The light beams in the R and G wavelength bands pass through the dichroic filter 11, and the light beams in the G wavelength band pass through the dichroic filter 1.
The liquid crystal panel 24 is illuminated after being separated by 2 and passing through the field lens 15. The luminous flux in the wavelength band of R is
After passing through the dichroic filter 12 and guided by a relay optical system including two total reflection mirrors 17 and 18 and two lenses 19 and 20, the light passes through the field lens 16 and illuminates the liquid crystal panel 25. Here, the distance between the liquid crystal panel 25 and the second lens array 10 is equal to the distance between the liquid crystal panels 23 and 24 and the second lens array 10.
Is different from the distance between the lenses 19 and 2 of the relay optical system.
By using 0, the illumination state of the liquid crystal panel 25 is made equal to the illumination state of the other liquid crystal panels 23 and 24.
Each of the first lenses 4a of the first lens array 4 and each of the three liquid crystal panels 23 to 25 are in an optically conjugate relationship, and each of the plurality of luminous fluxes divided by the first lens array 4 Since each is superimposed on the liquid crystal panels 23 to 25, the liquid crystal panels 23 to 25 are illuminated with a uniform light amount distribution. As a result, the RGB images displayed on the liquid crystal panels 23 to 25 are combined by the dichroic prism 21 and projected on the screen as a color image with a uniform illuminance distribution by the projection lens 22.

In this embodiment, as shown in FIG. 2B, the plane including the incident surface A2 of the second rectangular prism 5b is positioned in the sixth column from the left, as shown in FIG. Although it is configured to cross the center of the second lens 10a, the present invention is not limited to this. Instead of the polarizing beam splitter 5, the incident surface A2 of the second right-angle prism 5bα as shown in FIG. Using a polarizing beam splitter 5α configured to cross a boundary 10c located between the second lens 10a in the fifth row and the second lens 10a in the sixth row. Is also good. 3, each of a plurality of second lenses 10a included in the second lens array 10 is conjugate with the light source 1 in FIG.
In a liquid crystal projector or the like, generally, a liquid crystal illumination method called so-called Koehler illumination is adopted, and a light source is arranged conjugate with a pupil of a projection lens. In this case, each of the plurality of second lenses 10 a of the second lens array 10 is conjugate with the pupil of the projection lens 22. Generally, in a liquid crystal projector that employs an optical integrator, it is considered that unevenness of illuminance on a pupil does not affect an image on a screen. However, this is true only when the luminance distribution within the solid angle in which the liquid crystal panel is viewed from above the second lens array 10, ie, from above the pupil, is randomly non-uniform, and has a common tendency. In the case of non-uniformity, the effect appears on the image on the screen. Therefore, as shown in FIG. 3, the plane including the incident surface A2 of the second right-angle prism 5bα corresponds to the second lens 10 in the fifth column.
and a polarizing beam splitter 5α so as to cross a boundary 10c located between the second lens 10a and the second lens 10a in the sixth row.
With this configuration, it is possible to reliably prevent the influence of such non-uniformity from appearing on an image on a screen.

Also, in the present embodiment, the half-wave plate 10b is arranged on the entire exit surface of the second lens array 10 from which the light beam 7 is emitted. However, the present invention is not limited to this. Half-wave plate 1
0b may be arranged.

In this embodiment, the half-wave plate 10b
Is attached to the exit surface of the second lens 10a where the small light source formed by the light beam 7 is located.
Lens 10a in which the small light source formed by
May be attached to the exit surface of the camera. Further, the half-wave plate 10b may be attached to the second lens 10a in which all or a part of the small light source formed by the light beam 6 or 7 is located. However, when the half-wave plate 10b is attached to the exit surface of the second lens 10a where the small light source formed by the light beam 7 is located, the light beam 6 reflected on the polarization separation surface 5d and the light beam 7 transmitted through the polarization separation surface 5d This embodiment is more preferable because it has an effect of correcting an optical path difference between the first embodiment and the second embodiment.

Further, in this embodiment, a metal halide lamp is used as the light source 1, but a xenon lamp, a halogen lamp, or the like may be used.

Next, a second embodiment of the present invention will be described. FIG. 4 is a diagram showing first and second lens arrays, a polarizing beam splitter, and the like used in the second embodiment. Since most of the configuration and operation of the second embodiment are the same as those of the first embodiment, the description thereof is omitted, and a portion having a configuration different from that of the first embodiment, that is, a polarization beam splitter Will be described. The polarizing beam splitter 5β is a first prism made of triangular prism transparent glass or the like.
A right-angle prism 5a, a second right-angle prism 5bβ having a partial shape of a triangular prism and made of transparent glass or the like, and a first
And a polarization conversion surface 5dβ formed on the inclined surface behind the second right-angle prisms 5a and 5bβ, and a total reflection surface 5fβ arranged to face the polarization separation surface 5dβ at a distance of 5e from the polarization separation surface 5dβ. This is a separation unit of the optical system. Second
The right-angle prism 5bβ has a triangular prism partly cut for weight reduction, and thus has a trapezoidal columnar shape.
Therefore, in the present invention, the triangular prism includes a trapezoidal prism having a triangular prism cut, such as the second right-angle prism 5bβ. In FIG. 1, a polarization beam splitter 5β is used instead of the polarization beam splitter 5. At this time, the exit surface B of the first right-angle prism 5a
Since the plane including 1 crosses the boundary 4b, the blurred image of the ridge line C is not projected on the screen.

In the second embodiment, FIG.
4, the plane including the incident surface A2 of the second right-angle prism 5bβ corresponds to the second lens 10 in the fifth column.
a and a polarizing beam splitter 5β so as to cross a boundary 10c located between the second lens 10a in the sixth row.
May be configured.

Next, a third embodiment of the present invention will be described. FIG. 5 is a diagram showing the first and second lens arrays, the polarizing beam splitter, and the like used in the third embodiment. Since most of the configuration and operation of the third embodiment are the same as those of the first embodiment, the description thereof will be omitted, and a portion having a configuration different from that of the first embodiment, that is, a polarization beam splitter will be described. . The polarization beam splitter 5γ includes first and second triangular prism-shaped transparent glasses or the like.
And third right-angle prisms 5aγ, 5bγ, 5cγ and first, second, and third right-angle prisms 5aγ, 5bγ, 5c
This is a separation unit of the polarization conversion optical system constituted by a polarization separation surface 5dβ formed on the inclined surface behind γ and a total reflection surface 5fβ arranged to face the polarization separation surface 5dβ at an interval of a thickness 5e. In FIG. 1, the polarization beam splitter 5
, A polarization beam splitter 5γ is used. At this time, since the plane including each of the exit surfaces B1 and B2 of the first and second right-angle prisms 5aγ and 5bγ crosses the boundary 4b, the blurred image of the ridge lines E and F is projected on the screen. There is no.

It should be noted that also in the third embodiment,
As in FIG. 3, in FIG. 5, the plane including each of the incidence surfaces A2 and A3 of the second and third right-angle prisms 5bγ and 5cγ is the third lens of the second lens 10a and the fourth lens of the fourth prism, respectively. Boundary portion 10c located between the second lens 10a and the second lens 10a
The polarization beam splitter 5γ may be configured to cross the second lens 10a in the seventh row and the boundary 10c located between the second lens 10a in the eighth row.

Next, a fourth embodiment of the present invention will be described. FIG. 6 is a diagram showing first and second lens arrays, a polarization beam splitter, and the like used in the fourth embodiment. Since most of the configuration and operation of the fourth embodiment are the same as those of the first embodiment, the description thereof is omitted, and a portion having a configuration different from that of the first embodiment, that is, a polarization beam splitter is described. explain. The polarizing beam splitter 5δ is formed of a triangular prism-shaped transparent glass or the like.
And the second right-angle prisms 5aδ and 5bδ, the polarization separation surface 5dδ formed on the inclined surface behind the first and second right-angle prisms 5aδ and 5bδ, and the thickness 5 from the polarization separation surface 5dδ.
and e is a separation portion of the polarization conversion optical system constituted by the total reflection surface 5fδ opposed to and spaced apart by an interval e. In FIG. 1, a polarization beam splitter 5δ is used instead of the polarization beam splitter 5. At this time, the plane including the exit surface B1 of the first right-angle prism 5aδ crosses the boundary 4b, so that the blurred image of the ridge line C is not projected on the screen.

Note that in the fourth embodiment,
As in FIG. 3, in FIG. 6, the second right-angle prism 5b
The polarization beam splitter 5δ is set so that the plane including the incident surface A1 of δ crosses the boundary 10c located between the second lens 10a in the fifth row and the second lens 10a in the sixth row. You may comprise.

[0039]

As is apparent from the above, according to the present invention, since the polarizing beam splitter is cut, the liquid crystal projector can be reduced in weight, and unnecessary images are projected on the screen. The image on the screen can be maintained at high quality without being performed.

Further, according to the present invention, even if the weight of the polarization conversion optical system used in the liquid crystal projector is reduced, an image with non-uniform illuminance is not projected on the screen, and the image on the screen is heightened. Quality can be kept.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2A is a perspective view of a polarizing beam splitter 5, and FIG. 2B is a plan view including the polarizing beam splitter 5, a first lens array 4, a second lens array 10, and the like.

FIG. 3 is a diagram showing another structure of the polarization beam splitter 5 of FIG.

FIG. 4 is a diagram illustrating first and second lens arrays, a polarizing beam splitter, and the like used in a second embodiment of the present invention.

FIG. 5 is a diagram showing first and second lens arrays, a polarizing beam splitter, and the like used in a third embodiment of the present invention.

FIG. 6 is a diagram illustrating first and second lens arrays, a polarization beam splitter, and the like used in a fourth embodiment of the present invention.

FIG. 7 is a configuration diagram of a conventional illumination optical system.

[Explanation of symbols]

Reference Signs List 1 light source 2 parabolic mirror 2a reflecting surface 2b opening 4 first lens array 4a first lens 5,5α, 5β, 5γ, 5δ polarizing beam splitter 5a, 5aγ, 5aδ first rectangular prism 5b, 5bα, 5bβ, 5bγ, 5bδ Second right-angle prism 5cγ Third right-angle prism 5d, 5dβ, 5dδ Polarization separation surface 5e Thickness 5f, 5fβ, 5fδ Total reflection surface 6, 7 Light flux 8 Optical path 9 Lateral shift amount 10 Second lens array 10a Second lens 10b Half-wave plate 11, 12 Dichroic filter 13, 17, 18 Total reflection mirror 14, 15, 16 Field lens 19, 20 Lens 21 Dichroic prism 22 Projection lens 23, 24, 25 Liquid crystal panel

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

Claims (2)

[Claims] 1. A first lens array having a plurality of first lenses arranged two-dimensionally to divide light from a light source into a plurality of light fluxes, and said first lens array is reflected by a 45-degree slope to be incident. A separating unit that separates each of the plurality of light beams into first and second linearly polarized light beams whose polarization directions are orthogonal to each other, and converts one polarization direction of the first and second linearly polarized light beams into the other polarization direction; A polarization conversion optical system having a conversion unit, and a plurality of two-dimensionally arranged two-dimensionally corresponding to the plurality of first and second linearly polarized lights near where the first or second linearly polarized light converges. A liquid crystal projector comprising: an illumination optical system having a second lens and a second lens array in which the conversion unit is disposed on an incident surface or an exit surface side of the plurality of second lenses. The separation unit is composed of a plurality of triangular prism-shaped right-angle prisms. The inclined planes are continuously arranged so as to form the same plane, and among the planes including the exit planes of the plurality of right-angle prisms, planes crossing the first lens array are adjacent to each other. A liquid crystal projector characterized by crossing a boundary located between one lens. 2. A plane crossing the second lens array among planes including the respective entrance planes of the plurality of right-angle prisms, crossing a boundary located between the second lenses adjacent to each other. The liquid crystal projector according to claim 1, wherein: