JP2000075245A - Color liquid crystal projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the contrast and color purity of projected images. SOLUTION: This liquid crystal projector has a polarization beam splitter 50 which selects one of P or S polarized light rays among the light rays emitted from a light source 14, a dichroic prism 88 which separates the selected polarized light to color light rays of red, green and blue and synthesizes the respective modulated color light rays and liquid crystal display devices 80R, 80G, 80B of a reflection type which modulate the respective color light rays subjected to color sepn. and a projection lens 90 which projects the images onto a screen 100. In such a case, the rear surface side of a liquid crystal device body 81 is provided with reflection type polarizing plates (88R, 88G, 88B). The degrees of polarization of the modulation light emitted from the liquid crystal display devices 80R, 80G, 80B is enhanced by the polarized light selection effect of these reflection type polarizing plates 80R, 80G, 80B, by which the contrast and color purity of the projected images are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device in which a reflection optical member is integrally provided on the back side of a liquid crystal device, and light incident on the front side of the liquid crystal device is reflected by the reflection optical member on the back side of the liquid crystal device. The present invention relates to a color liquid crystal projector having a so-called reflective liquid crystal device that emits light modulated from the front side.

[0002]

2. Description of the Related Art A conventional color liquid crystal projector of this type is polarized and separated by polarization selecting means such as a polarizing beam splitter and separated by a color separating means such as a dichroic mirror or a dichroic prism.
The polarized light beam of blue) is modulated by a reflective liquid crystal device having a reflective optical member integrated on the back side, and then combined by a color combining means such as a dichroic prism, and projected as a color image on a screen by a projection optical system. It is displayed.

[0003]

However, in the above-mentioned conventional projector, the reflection optical member provided on the back side of the liquid crystal device is formed by a metal deposition film of aluminum or the like. The reflection efficiency was poor, and the light use efficiency was low. Furthermore, unless a polarizing plate for increasing the degree of polarization is provided on the light incident side of the polarization selection means (polarization beam splitter) or in front of the projection optical system, an image with good contrast and color purity cannot be obtained.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a reflecting optical member provided on the back side of a liquid crystal device, which transmits either P-polarized light or S-polarized light, Another object of the present invention is to provide a color liquid crystal projector which is excellent in image contrast and color purity by increasing the degree of polarization of a light beam guided to a color synthesizing unit by using a reflective polarizing plate that reflects the other.

[0005]

In a color liquid crystal projector according to the present invention, a light source and polarization selecting means for selecting either P-polarized light or S-polarized light from the light emitted from the light source are provided. Separating the polarized light selected by the polarization selecting means into a plurality of color lights, and color separating / combining means for combining the modulated color lights; and
It comprises a reflective liquid crystal device that modulates each color light separated by the synthesizing means and reflects and emits the light to the light incident surface side, and a projection optical system that projects an image synthesized by the color separating / synthesizing means. In the color liquid crystal projector, a reflective optical member is provided on a side of the liquid crystal device opposite to the light incident surface, and the reflective optical member is provided with P-polarized light or
It is configured by a reflective polarizing plate that transmits one of the polarized lights and reflects colored light in a predetermined wavelength range of the other polarized light.

Unlike a conventional projector, a polarizing plate is provided on the rear side of a liquid crystal device without having to provide a polarizing plate in front of the light incidence side of the polarization selecting means or the projection optical system. Thereby, the degree of polarization of the modulated light emitted from the liquid crystal device increases. Therefore, the contrast and color purity of the image are improved.

Further, since the color separating means and the color synthesizing means are constituted by a single member (color separating / synthesizing means), the number of parts is reduced, and the configuration of the projector is simple and compact.

Further, in the color liquid crystal projector according to the present invention, between the light source and the color separating / combining means,
A polarization conversion element for converting non-polarized light into one type of linearly polarized light; the polarization conversion element; a polarization separation film for separating light emitted from the light source into P-polarized light and S-polarized light; It is preferable that a configuration is provided that includes a reflective film that reflects one of the polarized lights separated by the film, and a retardation plate that aligns the polarization directions of the polarized lights separated by the polarized light separating film.

Since the polarization selecting process is performed by each of the polarization conversion element and the reflective polarizing plate, the degree of polarization of the modulated light is increased accordingly, and the contrast and color purity of the image are further improved.

Further, in the color liquid crystal projector according to the present invention, the light source, the color separation means for separating the light emitted from the light source into a plurality of color lights, Polarization selecting means for selecting either polarized light or s-polarized light, and a reflective liquid crystal device which modulates each polarized light selected by the polarized light selecting means and reflects and emits the light toward the light incident surface side. A color synthesizing means for synthesizing each color light modulated by the liquid crystal device, and a projection optical system for projecting an image synthesized by the color synthesizing means, wherein the light incident surface of the liquid crystal device is A reflection optical member is provided on the side opposite to the above, the reflection optical member transmits one of P-polarized light and S-polarized light, and reflects color light of a predetermined wavelength range in the other polarized light. And to constitute the reflective polarizer.

Unlike a conventional projector, a polarizing plate is provided on the back side of the liquid crystal device without having to provide a polarizing plate on the light incident side of the polarization selecting means or in front of the projection optical system. Thereby, the degree of polarization of the modulated light emitted from the liquid crystal device increases. Therefore, the contrast and color purity of the image are improved.

In the color liquid crystal projector of the present invention, a polarization conversion element for converting non-polarized light into one type of linearly polarized light is provided between the light source and the color separation means.
The polarization conversion element includes: a polarization separation film that separates light emitted from the light source into P-polarized light and S-polarized light; a reflection film that reflects one of the polarized lights separated by the polarization separation film; It is desirable to provide a configuration including a retardation plate for aligning the polarization direction of the polarized light separated by the separation film.

Since the polarization selecting process is performed by each of the polarization conversion element and the reflection type polarizing plate, the degree of polarization of the modulated light is increased accordingly, and the contrast and color purity of the image are further improved.

In the color liquid crystal projector according to the present invention, the color synthesizing means has a dichroic surface for reflecting the modulated light modulated by the liquid crystal device, and the modulated light reflected on the dichroic surface is an S-polarized light. It is desirable to be configured so that

The reflection efficiency on the dichroic surface is better for S-polarized light than for P-polarized light.
By reflecting the polarized light on the dichroic surface, the light use efficiency can be increased.

[0016]

Next, embodiments of the present invention will be described based on examples.

FIGS. 1 to 8 show an embodiment of a color liquid crystal projector according to the present invention. FIG. 1 is a plan view showing the entire configuration of a liquid crystal projector according to an embodiment of the present invention. FIG. 3 is a diagram showing a schematic configuration of a uniform illumination optical system and a polarization conversion optical system; FIG. 3 is a perspective view, a front view, and a side view of a lens array provided in the uniform illumination optical system; FIG. 5 is an explanatory view for explaining the function of the polarization conversion element array, FIG. 6 is a plan view of a light shielding plate provided in the polarization conversion element array, and FIG. FIG. 8 is an enlarged perspective view illustrating the configuration of the plate, and FIG. 8 is a diagram illustrating transmittance characteristics (reflectance characteristics) of the reflective polarizing plate.

In these figures, a color liquid crystal projector according to the present embodiment includes a light source 14, a polarization beam splitter 50 as polarization selection means for selecting S-polarized light from the light of the light source 14 which is non-polarized light, and a polarized light beam. The S-polarized light selected by the splitter 50 is separated into red, green, and blue color lights, and color separation and color synthesis for modulating each color light is performed.
A cross dichroic prism 88 as a synthesizing means;
The reflective polarizers 82R, 82G, and 82B are provided on the rear side to modulate the red, green, and blue color lights separated by the cross dichroic prism 88, respectively, and to reflect and emit the light to the light incident surface side. Reflective liquid crystal device 8
The optical system is provided with a projection lens 90 which is a projection optical system for projecting and displaying an image synthesized by the cross dichroic prism 88 on the screen 100.

The light source 14 and the polarization beam splitter 5
0, the first lens array 20 and the polarization conversion unit 3 constituting the uniform illumination optical system and the polarization conversion optical system.
0 and a superimposing lens 40 are provided.

Reference numeral 10 denotes a light source unit in which a metal halide lamp 14 as a light source is integrated with a reflector 12, and light from the light source 14 is guided to a beam splitter 50 via a uniform illumination optical system and a polarization conversion optical system.

As shown in FIG. 2, the first lens array 20 and the superimposing lens 40 constituting the uniform illumination optical system convert the light emitted from the light source unit 10 into a plurality of partial light beams 202.
, And superimposed on the liquid crystal devices 80R, 80G, and 80B, thereby forming a projected image with less uneven illuminance.

The first lens array 20 includes a small lens 201 having a rectangular outline and M rows in the vertical direction and 2 rows in the horizontal direction.
It has a configuration arranged in a matrix of N columns, and is arranged on the light emission side of the light source unit 10. In front of the first lens array 20, the second lens array 15
0, light shielding plate 140 and two polarization conversion element arrays 13
The polarization conversion unit 30 in which the
Are arranged so as to face the lens array 20, and the superimposing lens 40 is arranged with the reflection mirror 42 interposed therebetween.

The polarization conversion unit 30 includes the light source unit 1
And a polarization conversion optical system that converts each of the plurality of partial light beams 202 emitted from the first lens array 20 and divided by the first lens array 20 into one type of polarized light (S-polarized light in the embodiment). The light use efficiency is enhanced, and a bright projected image is obtained.

The second lens array 150 is, like the first lens array 20, a small lens 1 having a rectangular contour.
51 are arranged in a matrix of M rows in the vertical direction and 2N columns in the horizontal direction. Then, it has a function of guiding the partial light beam 202 split by the first lens array 20 to be condensed on the polarization splitting film 331 of the polarization beam splitter array 320 described later in detail.

As shown in FIG. 4, the polarization conversion element array 131 includes a polarization beam splitter array 320 and a λ / 2 phase difference plate 381 selectively disposed on a part of the light exit surface of the polarization beam splitter array 320. (Shown as diagonal lines)
And Polarizing beam splitter array 320
Has a shape in which a plurality of columnar translucent members 323 each having a parallelogram cross section are sequentially bonded. Polarized light separating films 331 and reflective films 332 are formed alternately on the interface of the light transmitting member 323. λ / 2 phase difference plate 38
Numeral 1 is selectively affixed to a mapping portion of the light exit surface of the polarization separation film 331 or the reflection film 332. In this example, λ / 2 is added to the mapping portion of the light exit surface of the polarization separation film 331.
The phase difference plate 381 is attached.

As shown in FIG. 6, light is incident on the light shielding plate 140 only on the light incident surface corresponding to the polarization separation film 331 among the light incident surfaces of the two polarization conversion element arrays 131. As described above, the configuration is such that the opening 141 is provided in a substantially rectangular plate-like body.

The polarization conversion element array 131 has a function of converting an incident light beam into one type of linearly polarized light (for example, S-polarized light or P-polarized light) and emitting the same. FIG. 5 is an explanatory diagram showing functions of the polarization conversion element array 131. Non-polarized light (incident light having a random polarization direction) including an S-polarized component and a P-polarized component is incident on the incident surface of the polarization conversion element array 131. This incident light is first transmitted to the polarization separation film 33.
1 separates the light into S-polarized light and P-polarized light. The S-polarized light is reflected almost vertically by the polarization separation film 331, and is further vertically reflected by the reflection film 332 before being emitted. On the other hand, the P-polarized light passes through the polarization separation film 331 as it is. A λ / 2 retardation plate 381 is disposed on the exit surface of the P-polarized light transmitted through the polarization separation film 331, and the P-polarized light is converted into S-polarized light and emitted. Therefore, most of the light that has passed through the polarization conversion unit 30 is S
The light is emitted as polarized light. In addition, the polarization conversion unit 3
When light emitted from 0 is to be P-polarized light, λ /
The two-phase-difference plate 381 may be arranged on the exit surface from which the S-polarized light reflected by the reflection film 332 exits.

The polarization conversion element array 132 is exactly the same as the polarization conversion element array 131, and a description thereof will be omitted. Then, the two polarization conversion element arrays 131 and 132
Are arranged symmetrically with respect to the optical axis of the light source unit 10, as shown in FIGS.

The polarization beam splitter 50 as a polarization selecting means selects only the S-polarized light emitted from the superimposing lens 40 and guides it to a cross dichroic prism 88 as an adjacent color separating / combining means. That is, the polarization beam splitter 50 is formed with a polarization separation film 52 that transmits P-polarized light and reflects S-polarized light, and the polarization separation film 52 is a light (mainly S-polarized light) emitted from the superimposing lens 40. ), And transmits only P-polarized light and reflects only S-polarized light.

The cross dichroic prism 88 separates the light guided from the polarization beam splitter 50 into light of three colors, red, green and blue, and separates the liquid crystal device 80 corresponding to each color light.
A function as a color separation means for leading to R, 80G, and 80B;
Each of the liquid crystal devices 80R, 80G, and 80B has both functions as a color synthesizing unit for synthesizing the modulated lights returned by being modulated by the liquid crystal devices 80R, 80G, and 80B to form a color image. That is, the cross dichroic prism 88 has a dielectric multilayer film 89R that reflects red light and transmits green light and blue light.
And a dielectric multilayer film 89B that reflects blue light and transmits red light and green light are formed in an approximately X shape along the interface between the four right-angle prisms. On the outer surface of the dichroic prism 88, on the back side of the liquid crystal device main body 81, as reflective optical members, reflective polarizing plates 82R, 82G,
82B, each of which is a reflection type liquid crystal device 80R,
80G and 80B are disposed respectively, and the red light reflected by the dielectric multilayer film 89R is applied to the liquid crystal device 80R.
And the blue light reflected by the dielectric multilayer film 89B is guided to the liquid crystal device 80B, and the dielectric multilayer film 89R,
The green light transmitted through 89B is guided to the liquid crystal device 80G.

Then, the reflection type liquid crystal devices 80R, 80R
G and 80B have a twisted nematic (TN) mode structure, and each color light (S-polarized light) incident on the liquid crystal device main body 81.
Are reflective polarizing plates 82R, 82R that pass through the liquid crystal device body 81 and
2G and 82B, respectively, and the liquid crystal device
When the light passes through 1, a part of the light is emitted as color light (P-polarized light) whose deflection axis is rotated by 90 degrees.

The reflection type polarizing plates 82R, 82G, 82
B is configured to reflect only the color light in the wavelength range corresponding to the color light (S-polarized light) incident on the liquid crystal device main body 81. The detailed structure of the reflective polarizer 20 is shown in FIG. Will be explained.

FIG. 7 shows the reflective polarizers 82R, 82G, 8
It is explanatory drawing which shows the structure of 2B. These reflective polarizing plates are composed of a multilayer structure film. The multilayer structure film is composed of a laminate of films formed by stretching a polymer, and has two different types of layers 601 (A layer) and 602 (B layer).
Layers) are alternately stacked in the Z-axis direction. The A layer 601 of the reflection type polarizing plate includes, for example, polyethylene naphthalate (PEN; polyethylene napthalat).
e) is stretched, and the B layer 602 is provided with a copolyester of napthalene dicarboxyl (coPEN) of naphthalene dicarboxylic acid and terephthalic acid.
ic acid and terephthallic or isothalic acid). Of course, the material of the reflective polarizing plate is not limited to this, and the material can be appropriately selected.

The refractive index (nAX) of the A layer 601 in the X-axis direction
And the refractive index (nAY) in the Y-axis direction are different from each other. on the other hand,
The refractive index of the B layer 602 in the X-axis direction (nBX) and the refractive index in the Y-axis direction (nBY) are set to be substantially equal. The refractive index (nAY) of the A layer 601 in the Y-axis direction is set to be substantially equal to the refractive index (nBY) of the B layer 602 in the Y-axis direction. That is, to summarize this, (nAX) ≠ (nAY), (nBX) ≒ (nBY)
≒ (nAY).

As described above, the linearly polarized light in the Y-axis direction (P-polarized light in the embodiment) of the light incident on the multilayer structure film is in a state in which there is substantially no difference in the refractive index between the laminations. Therefore, this multilayer structure film is transmitted as it is with its polarization axis.

On the other hand, the layer thickness of the A layer 601 in the Z-axis direction is t
When the thickness of the A and B layers 602 in the Z-axis direction is tB and the wavelength of the incident light is λ, the relationship is set so as to obtain the relationship of Expression (1).

TA · nAX + tB · nBX ≒ λ / 2 (1) As a result, of the light having the wavelength λ, the light of the linearly polarized light in the X-axis direction (S-polarized light in the embodiment) is converted into the light of the adjacent A layer. The light is reflected as polarized light in the X-axis direction at the interface between the layer and the layer B. By changing the layer thicknesses tA and tB of the A layer 601 and the B layer 602 variously, stacking them, and widening the reflection wavelength band (transmission wavelength band), a predetermined wavelength of linearly polarized light (S-polarized light) in the X-axis direction is obtained. The band can be reflected. The multilayer structure film may be formed by sequentially laminating layers having different thicknesses, or may be formed by laminating a plurality of laminates in which several layers having the same thickness are laminated. good. Further, in the above equation (1), it is preferable that the equal sign is completely established.

The reflective polarizing plate 8 thus formed
As shown in FIG. 8A, 2R has a characteristic of reflecting only the red wavelength range of the S-polarized light, transmitting the other wavelength range of the S-polarized light, and transmitting all the wavelength ranges of the P-polarized light. As shown in FIG. 8B, the reflective polarizer 82G reflects only the light in the green wavelength range of the S-polarized light, and changes the other wavelength range of the S-polarized light and all the wavelength ranges of the P-polarized light. As shown in FIG. 8C, the reflective polarizing plate 82B has the property of transmitting light,
It has the property of reflecting only light in the blue wavelength range of S-polarized light and transmitting other wavelength ranges of S-polarized light and all wavelength ranges of P-polarized light.

Then, each of the reflection type polarizing plates 82R, 82G,
The liquid crystal devices 80R and 80B are arranged in such a manner that a deflection axis is rotated by 45 degrees around the incident axis (Z axis) of light to each liquid crystal device main body with respect to the liquid crystal device main body 81.
The S-polarized light that has entered the G and 80B becomes P-polarized light having a high degree of polarization due to the polarization selecting action of the reflective polarizer, and is emitted from each of the liquid crystal devices 80R, 80G and 80B.

Then, the liquid crystal devices 80R, 80G, 80B
Red, green, and blue modulated light (P-polarized light) emitted from the light source are combined by the dielectric multilayer films 89R and 89B of the cross dichroic prism 88, which is also a color combining means, to provide a combined light for projecting a color image. Is formed. The combined light generated by the cross dichroic prism 88 is transmitted through the polarization beam splitter 50 (polarization separation film 52) and guided to the projection lens 90. The projection lens 90 has a function of projecting the synthesized light on the projection screen 100, and displays a color image on the projection screen 100.

FIG. 9 is a plan view showing a color liquid crystal projector according to another embodiment of the present invention, and showing the entire configuration of the projector.

In the above-described first embodiment, the dichroic prism 88 has a structure in which both the functions of color separation and color synthesis are provided. Cross dichroic prism 88A
And a second cross dichroic prism 88B as a color synthesizing means, and the light guided from the superimposing lens 40 is converted into red, green, and blue light by the first dichroic prism 88A, the reflection mirror 44, and the dichroic mirror 46. After separation, the polarization beam splitters 50R, 50G, and 50B, which are polarization selection means, are configured to select polarized light of each color light and to guide the polarized light to each of the liquid crystal devices 80R, 80G, and 80B.

First cross dichroic prism 88
A indicates a dielectric multilayer film 89 that reflects red light and green light.
RG and a dielectric multilayer film 89B that reflects blue light are formed in a substantially X-shape along the interface of the four right-angle prisms, and light (S-polarized light) that has passed through a uniform illumination optical system and a polarization conversion optical system. Light) is the first cross dichroic prism 88A.
As a result, the light is separated into two lights, a mixed light of red and green, and a blue light.

The mixed light of red and green separated by the dichroic prism 88A is reflected by the reflection mirror 44.
And is guided to a dichroic mirror 46 that transmits red light and reflects green light. The red light is transmitted through the dichroic mirror 46 to the polarization beam splitter 50R, and the green light is reflected by the dichroic mirror 46 and guided to the polarization beam splitter 50G. On the other hand, the green light separated by the dichroic prism 88A is guided to the polarization beam splitter 50B by the reflection mirror.

Each of the polarization beam splitters 50R, 50G, and 50B serving as polarization selection means is formed with a polarization separation film 52 that reflects S-polarized light and transmits P-polarized light. Only the respective S-polarized light components of the light correspond to the corresponding reflective liquid crystal devices 80R, 80G, 80.
It is led to B. The liquid crystal devices 80R, 80G, and 80B are provided on the rear side of the liquid crystal device main body 81 with the reflective polarizing plates 82R,
The liquid crystal devices 80R, 80G, and 80B have the same structure as the liquid crystal device of the first embodiment in which G and 82B are integrated.
Are respectively modulated in accordance with the given image information, and a part thereof is emitted as modulated light (P-polarized light).

The modulated light (P-polarized light) of each color emitted from the liquid crystal devices 80R, 80G, and 80B passes through the polarization separation films 52 of the polarization beam splitters 50R, 50G, and 50B, and serves as a color combining means. No. 2 cross dichroic prism 88B. Dichroic prism 88
B has the same structure as the dichroic prism 88 of the first embodiment described above, combines the respective color lights, and projects this combined light onto the screen 100 by the projection lens 90.

The polarization beam splitters 50R, 50R
B and the dichroic prism 88B, between the red light and the blue light incident on the dichroic prism 88B,
A λ / 2 retardation plate 60 for converting P-polarized light to S-polarized light is provided.

That is, the reflection efficiency of the dielectric multilayer films 89R and 89B formed on the dichroic prism 88B is higher for the S-polarized light than for the P-polarized light, and the transmission efficiency for the dielectric multilayer films 89R and 89B. Is better for P-polarized light than for S-polarized light. Therefore, the polarization beam splitter 5
Green light, which is P-polarized light guided from 0G, passes through the dielectric multilayer films 89R and 89B as it is, and red light and blue light, which are P-polarized light guided from the polarization beam splitters 50R and 50B, are converted into S-polarized light. And the dielectric multilayer film 89
By reflecting at R, 89B, light loss is reduced,
We are trying to make effective use of light. Note that the λ / 2 phase difference plate 60 is not necessarily provided.

The other parts are the same as those of the first embodiment, and the same reference numerals are used to omit the description.

It should be noted that the present invention is not limited to the above-described embodiment, and the following modified examples can be considered.

That is, in the above-described embodiment, the polarization conversion unit 30 is provided in front of the light source unit 10 so that light incident on the polarization beam splitter 50 or the dichroic prism 88A is adjusted to be S-polarized light or P-polarized light. However, the polarization conversion unit 30 need not always be provided.

In the above embodiment, the mode of the liquid crystal used in the liquid crystal device is described as TN. However, the present invention is not limited to this mode. Any liquid crystal can be used as long as it can emit linearly polarized light. Then, for such a liquid crystal, the direction of the reflective polarizing plate may be set in the best direction as appropriate with respect to the change of the polarization axis.

[Brief description of the drawings]

FIG. 1 is a plan view showing the overall configuration of a color liquid crystal projector according to an embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a uniform illumination optical system and a polarization conversion optical system.

3A is a perspective view of a lens array provided in a uniform illumination optical system, FIG. 3B is a front view of the lens array,
(C) is a side view of the lens array.

FIG. 4 is a perspective view of a polarization conversion element array which is a main part of the polarization conversion optical system.

FIG. 5 is an explanatory diagram illustrating functions of the polarization conversion element array.

FIG. 6 is a plan view of a light shielding plate provided in the polarization conversion element array.

FIG. 7 is an enlarged perspective view illustrating the configuration of a reflective polarizing plate.

FIG. 8 is a diagram showing transmittance characteristics (reflectance characteristics) of a reflective polarizing plate.

FIG. 9 is a plan view showing the overall configuration of a color liquid crystal projector according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Light source unit 12 Reflector 14 Metal halide lamp which is a light source 20, 150 Lens array 30 Polarization conversion unit 40 Superposition lens 42, 44, 48 Reflection mirror 46 Dichroic mirror 50 which is a color separation means 50, 50R, 50G, 50B It is a polarization selection means. Polarization beam splitter 52 Polarization separation film 60 λ / 2 phase difference plate 80R, 80G, 80B Reflection type liquid crystal device 81 Liquid crystal device main body 82R, 82G, 82B Reflection type polarization plate 88 Cross dichroic prism 88A as color separation / synthesis means 88A Color Cross dichroic prism 88B as separating means Cross dichroic prism 89R as color combining means 89R, 89B, 89RG Dielectric multilayer film 90 Projection lens 100 Projection screen

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03B 33/12 G03B 33/12 F term (Reference) 2H042 CA06 CA10 CA14 CA17 2H049 BA02 BA06 BA25 BB03 BC22 2H088 EA14 EA15 EA16 EA18 HA13 HA15 HA20 HA21 HA24 HA25 HA28 MA02 2H091 FA05Z FA08Z FA10Z FA14Z FA26X FA26Z FA29Z FA41Z LA17 MA07 2H099 AA12 BA09 CA01 CA08 CA11 DA05

Claims (5)

[Claims] 1. A light source, polarization selecting means for selecting either P-polarized light or S-polarized light from light emitted from the light source, and a plurality of polarized lights selected by the polarization selecting means. A color separation / synthesis unit that separates the color lights and synthesizes the modulated color lights; and a reflection unit that modulates each color light separated by the color separation / synthesis unit and reflects the light toward the light incident surface side and emits the light. Liquid crystal device, and a color liquid crystal projector including a projection optical system that projects an image synthesized by the color separation / synthesis unit, wherein a reflection optical member is provided on a side of the liquid crystal device opposite to the light incident surface. And the reflecting optical member is a P-polarized light or S-polarized light.
A color liquid crystal projector comprising a reflective polarizing plate that transmits one of polarized lights and reflects colored light in a predetermined wavelength range of the other polarized light. 2. A polarization conversion element for converting non-polarized light into one type of linearly polarized light is provided between the light source and the color separation / synthesis unit, and the polarization conversion element emits light from the light source. Polarizing film that separates the polarized light into P-polarized light and S-polarized light, a reflecting film that reflects one of the polarized lights separated by the polarized light separating film, and a polarization direction of the polarized light separated by the polarized light separating film. 2. The color liquid crystal projector according to claim 1, further comprising: a retardation plate that aligns the colors. 3. A light source, a color separation means for separating light emitted from the light source into a plurality of color lights, and one of P-polarized light and S-polarized light among the color lights separated by the color separation means. A polarization selecting means for selecting a polarization mode, a polarization type liquid crystal device which modulates each polarized light selected by the polarization selecting means, and reflects and emits light toward the light incident surface side, and each color modulated by the liquid crystal device. In a color liquid crystal projector comprising a color synthesizing unit for synthesizing light and a projection optical system for projecting an image synthesized by the color synthesizing unit, a reflective optical member is provided on a side of the liquid crystal device opposite to the light incident surface. Is provided, and the reflection optical member is a P-polarized light or
A color liquid crystal projector comprising a reflective polarizing plate that transmits one of polarized lights and reflects colored light in a predetermined wavelength range of the other polarized light. 4. The image forming apparatus according to claim 1, further comprising:
A polarization conversion element for converting non-polarized light into one type of linearly polarized light, the polarization conversion element comprising: a polarization separation film that separates light emitted from the light source into P-polarized light and S-polarized light; 4. The device according to claim 3, further comprising: a reflection film that reflects one of the polarized lights separated by the separation film; and a retardation plate that aligns the polarization direction of the polarized light separated by the polarization separation film. Color LCD projector. 5. The color synthesizing means has a dichroic surface for reflecting modulated light modulated by the liquid crystal device, and the modulated light reflected on the dichroic surface is S-polarized light. The color liquid crystal projector according to claim 3, wherein: