JP2002365618A - Liquid crystal light valve and liquid crystal projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal light valve provided with both a dust preventing function and a function for telecentrically irradiating a liquid crystal panel with incident light and capable of contributing to the decrease of the size of the liquid crystal projector, and to provide the liquid crystal projector. SOLUTION: A lens function for telecentrically irradiating the liquid crystal panel 21 with the incident light is incorporated into an incident light side dust preventing glass 11 stuck to the surface of the incident side of the liquid crystal panel 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal light valve and a liquid crystal projector.

[0002]

2. Description of the Related Art FIG. 5 is a diagram showing an optical system of a conventional liquid crystal projector 400. The projector 400 includes the light source 4
10, an illumination optical system 430 for reflecting the light from the light source 410 and uniformly illuminating the illuminance distribution of the reflected light from the reflector 420 to uniformly illuminate the liquid crystal light valve 480; The light beam W emitted from the illumination optical system 430 is separated into red, green, and blue light beams R, G, and B, and the red light beam R and the green light beam G are guided to the corresponding liquid crystal light valves 480, respectively. System 440
And a relay optical system 450 that guides the blue light beam B having a long optical path to the corresponding liquid crystal light valve 480 among the color light beams separated by the color light separation optical system 440, and converts each color light beam with respect to its central axis (principal ray). Three condenser lenses 460 for converting into parallel light beams, and a condenser lens 4
Three incident-side polarizing plates 470 that regulate the polarization direction of the light transmitted through the light 60 to a predetermined direction and emit the light;
Three liquid crystal light valves 480 that modulate each color light beam from 0 according to given image information, three emission-side polarizing plates 490 that transmit only one polarization component of each modulated color light beam, A color synthesizing prism 500 for synthesizing each color light beam and a projection lens 510 for enlarging and projecting the synthesized light beam on the screen SC are provided.

[0003] The illumination optical system 430 includes a first lens array 431, a second lens array 432, a polarization conversion element 433, and a superposition lens 4 in addition to the light source 410 and the reflecting mirror 420.
34, and the light emitted from the light source 410 is
20 and the reflected light is reflected by the first lens array 431.
, And each of the partial light beams is divided into the second lens array 432 and the polarization conversion element 43.
The light is made incident on the superimposing lens 434 via the lens 3, and the plurality of incident partial light beams are superimposed on the liquid crystal light valve 480 by the superimposing lens 434 for irradiation.

The color light separating optical system 440 includes a blue-green reflecting dichroic mirror 441 and a green reflecting dichroic mirror 4.
And a reflecting mirror 443, which separates the light beam W emitted from the illumination optical system 430 into red, green, and blue light beams R, G, and B, and separates the red light beam R and the green light beam G into corresponding liquid crystals. It leads to the light valve 480.

The relay optical system 450 includes two single lenses (a first relay lens 451 and a second relay lens 453).
And the reflecting mirrors 452 and 454, and guides the blue light flux B to the corresponding liquid crystal light valve 480 while maintaining its intensity by passing through these optical elements.

[0006] The liquid crystal light valve 480 is connected to the liquid crystal panel 4.
The liquid crystal panel 481 has dustproof glass 485 adhered to both surfaces thereof. This dustproof glass 485
Is for preventing dust or the like from adhering to the surface of the liquid crystal panel 481. Further, even if dust or the like adheres to the surface of the dust-proof glass 485 itself, the distance to the liquid crystal surface of the liquid crystal panel 21 is increased so that the projected image is not affected. is there. The liquid crystal panel 481 has liquid crystal 483 sealed between a counter substrate 482 and a TFT substrate 484, and controls each liquid crystal pixel by a TFT to modulate light from the light source 410.

The liquid crystal light valve 4 constructed as described above
An incident side polarizing plate 470 and an outgoing side polarizing plate 490 are arranged on the incident side and the outgoing side of 80, respectively. Since the incident side polarizing plate 470 and the outgoing side polarizing plate 490 generate heat by light absorption, cooling spaces are provided on each of the incident side and the outgoing side, and these heats are not directly transmitted to the liquid crystal light valve 480. It is like
In addition, air is blown into the cooling space by a cooling fan (not shown) so that a rise in temperature is suppressed.

The condenser lens 460 has a function of illuminating the liquid crystal light valve 480 by converting each of the plurality of partial light beams from the superimposing lens 434 into a telecentric system (an optical system in which the light beams of the respective partial light beams are parallel to the principal ray). By thus illuminating the liquid crystal panel 481 in a telecentric manner, a clear projected image free from illumination unevenness and color unevenness during modulation can be obtained.

[0009]

However, in such a conventional liquid crystal projector 400, a plurality of elements (condenser lens 460, liquid crystal light valve 48) are used.
0, the color combining prism 500) is arranged while securing a cooling space on each of the incident side and the exit side of the incident side polarizing plate 470 and the exit side polarizing plate 490, and therefore, within the two-dot chain line in FIG. The area C shown inevitably becomes large, which hinders downsizing of the liquid crystal projector 400. Therefore, the applicant pays attention to the fact that the dustproof glass 485 is provided on the incident side surface of the liquid crystal panel 481, and the function of irradiating the incident side dustproof glass 485 with the incident light to the liquid crystal panel 481 in a telecentric manner. That is, by providing the function of the condenser lens 460 and omitting the condenser lens 460 provided on the incident side of the incident side polarizing plate 470,
The idea was to reduce the overall configuration.

An object of the present invention is to provide a liquid crystal light valve and a liquid crystal projector which have both a dustproof function and a function of irradiating incident light to a liquid crystal panel in a telecentric manner, and which can contribute to miniaturization of the liquid crystal projector. I do.

[0011]

According to the present invention, there is provided a liquid crystal light valve comprising a liquid crystal panel and an entrance dust-proof glass adhered to the entrance surface of the liquid crystal panel. Glass is provided with a lens function of irradiating incident light to a liquid crystal panel in a telecentric manner.

Further, in the liquid crystal light valve according to the present invention, the entrance-side dustproof glass is a convex lens having a curvature on the entrance surface side.

According to these inventions, it is possible to obtain a liquid crystal light valve having both a dustproof function and a function of irradiating incident light to the liquid crystal panel telecentrically. Therefore, when the liquid crystal light valve is applied to a liquid crystal projector, it is necessary to separately provide a lens (a condenser lens in an embodiment described later) for irradiating the liquid crystal panel with the incident light in a telecentric manner, in addition to the liquid crystal light valve. Therefore, it is possible to obtain a liquid crystal light valve that can contribute to downsizing of a liquid crystal projector without any problem.

Further, the liquid crystal light valve according to the present invention comprises:
The convex lens is made of high refractive index glass.

According to the present invention, since the convex lens is made of glass having a high refractive index, the curvature of the convex lens in forming the telecentric optical system can be reduced. Therefore, the liquid crystal light valve can be made thin and a compact liquid crystal light valve can be obtained.

Further, the liquid crystal light valve according to the present invention comprises:
The convex lens is made of sapphire glass.

According to the present invention, since the entrance-side dustproof glass is made of sapphire glass having a high refractive index, the same effect as that of the above-described high refractive index glass can be obtained, and sapphire glass has high thermal conductivity. Because it also has the feature of
There is also an effect that the heat of the liquid crystal panel can be efficiently radiated, and a liquid crystal light valve having a high cooling effect can be obtained.

Further, the liquid crystal light valve according to the present invention comprises:
The entrance-side dustproof glass is a gradient index lens.

According to the present invention, it is possible to obtain a compact liquid crystal light valve having both a dustproof function and a function of irradiating incident light to a liquid crystal panel telecentrically.

Further, in the liquid crystal light valve according to the present invention, the refractive index distribution type lens has a flat plate shape.

According to the present invention, since the gradient index lens is formed in a flat plate shape, when this liquid crystal light valve is applied to a liquid crystal projector, the incidence side polarizing plate is provided on the incidence side surface of the gradient index lens. It is possible to obtain a liquid crystal light valve that can be attached and contribute to miniaturization of the liquid crystal projector.

Further, the liquid crystal light valve according to the present invention comprises:
The entrance-side surface of the entrance-side dustproof glass is provided with an antireflection coating.

According to the present invention, an antireflection coating is applied to the entrance side surface of the entrance side dustproof glass, so that a liquid crystal light valve capable of increasing light transmittance and improving light use efficiency is obtained. It becomes possible.

Further, the liquid crystal light valve according to the present invention comprises:
The antireflection coating applied to the entrance side surface of the entrance side dustproof glass is made conductive.

According to the present invention, since the antireflection coating is made of a conductive material, it is possible to prevent adhesion of dust and the like due to static electricity, and to obtain a liquid crystal light valve capable of providing a clear image. Become.

Further, in the liquid crystal light valve according to the present invention, the outer shape of the entrance side dustproof glass is set to be substantially the same as the outer shape of the liquid crystal panel.

According to the present invention, the entrance-side dust-proof glass is formed to have a minimum necessary size with an outer shape substantially the same as the outer shape of the liquid crystal panel, so that the overall configuration of the liquid crystal light valve can be reduced in size. Become.

Further, the liquid crystal light valve according to the present invention comprises:
The emission-side dustproof glass is attached to the emission-side surface of the liquid crystal panel.

According to the present invention, since the emission-side dust-proof glass is adhered to the emission-side surface of the liquid crystal panel, it is possible to obtain a liquid crystal light valve having more excellent dust-proof properties.

A liquid crystal projector according to the present invention includes any one of the liquid crystal light valves described above.

According to the present invention, since any one of the liquid crystal light valves described above is provided, it is possible to obtain a compact liquid crystal projector having both a dustproof function and a function of illuminating the liquid crystal panel telecentrically. Become.

Further, the liquid crystal projector according to the present invention comprises:
The liquid crystal light valve is provided with the entrance-side dust-proof glass having a flat plate-like refractive index distribution type lens, and the entrance-side polarizing plate is attached to the entrance-side surface of the entrance-side dust-proof glass of the liquid-crystal light valve.

According to the present invention, since the incident side polarizing plate is attached to the incident side surface of the incident side dustproof glass, a more compact liquid crystal projector can be obtained.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a diagram illustrating a liquid crystal light valve according to Embodiment 1 of the present invention, and FIG. 2 is a diagram illustrating a liquid crystal projector in which the liquid crystal light valve of FIG. 1 is incorporated.

In FIG. 1, a liquid crystal light valve 1 includes an entrance-side dustproof glass 11 which is a feature of the first embodiment;
A liquid crystal panel 21 and an emission-side dustproof glass 31 are provided.

The entrance-side dustproof glass 11 has an outer shape substantially the same as the outer shape of the liquid crystal panel 21. It prevents dust and the like from adhering. Even if dust or the like adheres to the incident side surface of the incident side dust-proof glass 11 itself, the projected image is not affected by increasing the distance from the liquid crystal surface of the liquid crystal panel 21. It was made.

The entrance-side dustproof glass 11 has a lens function of irradiating the liquid crystal panel 21 with incident light telecentrically. In the first embodiment, the entrance-side dustproof glass 11 has a convex shape on the incident side. A convex lens is used. The entrance-side dustproof glass 11 is made of a high-refractive-index glass (having a refractive index of, for example, 1.5 to 1.8) or sapphire glass (having a refractive index of 1.77) having a high refractive index, and has a lens surface constituting a telecentric optical system. The curvature of 11a can be reduced. That is, if the curvature can be reduced,
Since the thickness of the lens surface 11a can be reduced, the width (length in the horizontal direction in the figure) of the entrance-side dustproof glass 11 can be reduced, and the entire liquid crystal light valve 1 can be made thin. The surface of the lens surface 11a is coated with a conductive anti-reflection coating.

The liquid crystal panel 21 includes a counter substrate 22 and a TFT.
A liquid crystal 24 is sealed between the substrate 23 and the TF.
Each liquid crystal pixel is controlled by T to modulate incident light.

The emission-side dust-proof glass 31 has an outer shape substantially the same as the outer shape of the liquid crystal panel 21, is adhered and fixed to the emission-side surface of the liquid crystal panel 21, and is attached to the emission-side surface of the liquid crystal panel 21. Prevents dust from adhering. Further, even if dust or the like adheres to the emission-side surface of the emission-side dustproof glass 31 itself, the liquid crystal panel 21
By increasing the distance to the liquid crystal surface, the projected image is not affected.

The liquid crystal light valve 1 thus configured
Since the entrance side dustproof glass 11 has the function of the above-mentioned conventional condenser lens, the liquid crystal light valve 1 having both the dustproof function and the function of the telecentric optical system can be obtained. Thereby, when the liquid crystal light valve 1 is applied to a liquid crystal projector, FIG.
In the conventional liquid crystal projector 400 shown in FIG. 2, the condenser lens 460 separately provided in addition to the liquid crystal light valve 480 can be omitted, and the liquid crystal light valve 1 which can contribute to the miniaturization of the liquid crystal projector can be omitted. Obtainable.

Further, since the entrance-side dustproof glass 11 is made of high-refractive-index glass, the curvature of the lens provided on the entrance surface can be reduced, and the liquid crystal light valve 1 can be made thin.

Further, since the anti-reflection coating is applied to the surface on the incident side of the lens surface 11a, it is possible to increase the light transmittance and improve the light use efficiency,
In addition, since the antireflection coating is made of a conductive material, it is possible to prevent dust and the like from adhering due to static electricity, and to obtain a clearer image.

When the entrance-side dustproof glass 11 is made of sapphire glass having good thermal conductivity, heat radiation of the liquid crystal panel 21 is promoted, and the liquid crystal light valve 1 having good cooling efficiency can be obtained. Becomes possible.

Further, the outer shapes of the entrance-side dustproof glass 11 and the output-side dustproof glass 31 are set to be substantially the same as the outer shapes of the counter substrate 22 and the TFT substrate 24, respectively, and are set to the minimum necessary size. The liquid crystal light valve 1 can be obtained.

FIG. 2 is a view showing a three-panel type liquid crystal projector to which the liquid crystal light valve 1 configured as described above is applied.

The projector 100 includes a light source 110 composed of a high-intensity lamp such as a metal halide lamp.
An illumination optical system 130 for uniformly illuminating the illuminance distribution of the reflected light from the reflector 120 and uniformly illuminating the liquid crystal light valve 1; A color light separation optical system that separates the light beam W emitted from the illumination optical system 130 into red, green, and blue light beams R, G, and B, and guides the red light beam R and the green light beam G to the corresponding liquid crystal light valves 1. 140, a relay optical system 150 that guides a blue light beam B having a long optical path among the color light beams separated by the color light separation optical system 140 to the corresponding liquid crystal light valve 1, and a polarization direction of each color light beam that is regulated in a predetermined direction. Three incident-side polarizing plates 160 that emit light, three liquid crystal light valves 1 each including a liquid crystal panel 21 that modulates each color light beam in accordance with given image information, and three of the modulated color light beams. And three exit side polarizer 170 that transmits only the polarization component, a color synthesis prism 180 for combining the respective color light fluxes transmitted, synthesized light flux screen S
And a projection lens 190 for performing enlarged projection on C.

The illumination optical system 130 includes, in addition to the light source 110 and the reflecting mirror 120, a first lens array 131, a second lens array 132, a polarization conversion element 133,
34, the light emitted from the light source 110 is reflected by the reflecting mirror 120, the reflected light is divided into a plurality of partial light beams by the first lens array 131, and each of the partial light beams is The light is made incident on the superimposing lens 134 via the array 132 and the polarization conversion element 133, and each of the plurality of incident partial light beams is superimposed on the liquid crystal light valve 1 by the superimposing lens 134. The liquid crystal light valve 1 is uniformly illuminated by such superimposed illumination.

The color light separating optical system 140 includes a blue-green reflecting dichroic mirror 141 and a green reflecting dichroic mirror 1.
42 and a reflecting mirror 143. The blue-green reflecting dichroic mirror 141 transmits the red light component of the illumination light W from the illumination optical system 130 and reflects the blue light component and the green component. The transmitted red light flux R is
The light is reflected by the reflecting mirror 143 and reaches the corresponding liquid crystal light valve 1. On the other hand, the blue-green reflecting dichroic mirror 14
Of the blue light beam B and the green light beam G reflected by 1, the green light beam G is reflected by the green reflecting dichroic mirror 142 and reaches the corresponding liquid crystal light valve 1. on the other hand,
The blue light beam B also passes through the green reflecting dichroic mirror 142 and enters the relay optical system 150.

The relay optical system 150 includes a first relay lens 151 for condensing light on the second relay lens 153 and the reflecting mirror 1.
52, a second relay lens 153, and a reflecting mirror 154. The first relay lens 151 is disposed near the image plane of the primary image of the first lens array 131, and has a function of condensing the light beam forming the primary image on the second relay lens 153. Is the first relay lens 1
The light beam guided from 51 is re-imaged to form a liquid crystal light valve 1
It has a function of forming a secondary image thereon, and guides the blue light flux B to the corresponding liquid crystal light valve 1 while maintaining its intensity by passing through each of these optical elements.

Then, each color light separated into each color of RGB is led to the corresponding liquid crystal light valve 1. Here, the incident side polarizing plate 16 is provided on the incident side of the liquid crystal light valve 1.
Since 0 is provided, only light aligned in a predetermined polarization direction is incident on the liquid crystal light valve 1. Then, each color light aligned in a predetermined polarization direction is applied to the liquid crystal panel 21 of the corresponding liquid crystal light valve 1.
And is modulated according to the given image information (image signal). Then, the modulated color lights are emitted through the corresponding output-side polarizing plates 170 and enter the color combining prism 180.

The three color lights incident on the color combining prism 180 are combined by the color combining prism 180, and the combined light is projected on the screen SC by the projection lens 190.

The liquid crystal projector 1 thus configured
In FIG. 5, since the liquid crystal light valve 1 of the present invention is used, the conventional liquid crystal projector 4 shown in FIG.
In the case of 00, the condenser lens 460 separately provided in addition to the liquid crystal light valve 480 can be omitted. Thus, as is apparent from a comparison between FIG. 2 showing the liquid crystal projector 100 of the first embodiment and FIG. 5 showing the conventional liquid crystal projector 400, the area A indicated by the two-dot chain line in FIG. Area C (see FIG. 5), and the overall configuration of the liquid crystal projector 100 can be reduced in size.

Embodiment 2 FIG. 3 shows a liquid crystal light valve according to Embodiment 2 of the present invention. Embodiment 2
The liquid crystal light valve 201 of the first embodiment is the same as the liquid crystal light valve 1 of the first embodiment shown in FIG.
Is replaced by an entrance-side dust-proof glass 41. The entrance-side dust-proof glass 41 is a flat-plate-shaped gradient index lens. The graded index lens transmits incident light to the liquid crystal panel 2.
It has a function of irradiating 1 with telecentricity. In addition, a conductive antireflection coating is applied to the surface of the entrance-side dust-proof glass 41 on the entrance side.

With this configuration, substantially the same operation and effect as those of the first embodiment can be obtained, and
As the entrance-side dustproof glass 41, the refractive index distribution type lens adhered to the entrance side surface of the liquid crystal panel 21 is formed in a flat plate shape. Therefore, as shown in FIG. In this case, the incident-side polarizing plate can be attached to the incident-side surface of the incident-side dustproof glass 41, and the liquid crystal light valve 201 that can contribute to further downsizing of the liquid crystal projector can be obtained.

FIG. 4 is a view showing a liquid crystal projector incorporating the liquid crystal light valve of FIG. In FIG. 4, the same portions as those shown in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted or simplified.

In the liquid crystal projector 300 shown in FIG. 4, the incident side polarizing plate 160 is attached to the incident side surface of the incident side dustproof glass 41 of the liquid crystal light valve 201 as described above. In this way, the area B indicated by the two-dot chain line can be made smaller than the area A of the first embodiment shown in FIG. 2, and a more compact liquid crystal projector 300 can be obtained. In addition, it may be arranged away from the liquid crystal light valve 201 as in FIG. 2 in consideration of the cooling efficiency. In this case, the region B is smaller than the conventional region C shown in FIG.
A compact liquid crystal projector 300 can be obtained.

In the above embodiment, the case where the liquid crystal light valve of the present invention is applied to a transmission type liquid crystal projector is described as an example. However, the present invention can be applied to a reflection type liquid crystal projector. It is possible. Here, "transmission type" means that the liquid crystal light valve is a type that transmits light, and "reflection type" means that the liquid crystal light valve is a type that reflects light. I have. In a liquid crystal projector employing a reflection type liquid crystal light valve, a color combining prism is used as a color light separating means for separating light into three lights of red, green and blue, and the modulated three lights are combined. It may also be used as a color light combining unit that emits light in the same direction. Even when the present invention is applied to a reflective liquid crystal projector, substantially the same effects as those of a transmissive liquid crystal projector can be obtained.

Further, in the above-described embodiment, the front projection type display device which performs projection from the direction in which the projected image is observed has been described as an example, but rear projection in which projection is performed from the side opposite to the direction in which the projected image is observed. It is also possible to apply the liquid crystal light valve of the present invention to a portable projector.

In the above embodiment, the case where the liquid crystal light valve of the present invention is applied to a so-called three-panel type liquid crystal projector using three liquid crystal light valves has been described as an example. Alternatively, the present invention can be applied to a two-panel or four-panel liquid crystal projector using four projectors.

[Brief description of the drawings]

FIG. 1 is a diagram showing a liquid crystal light valve according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an optical system of a liquid crystal projector in which the liquid crystal light valve of FIG. 1 is incorporated.

FIG. 3 is a diagram showing a liquid crystal light valve according to a second embodiment of the present invention.

FIG. 4 is a diagram showing an optical system of a liquid crystal projector in which the liquid crystal light valve of FIG. 3 is incorporated.

FIG. 5 is a diagram showing an optical system of a conventional liquid crystal projector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 201 Liquid crystal light valve 11 Incident side dustproof glass (convex lens) 41 Incident side dustproof glass (refractive index distribution type lens) 21 Liquid crystal panel 31 Outgoing side dustproof glass 100, 300 Liquid crystal projector 160 Incident side polarizing plate 170 Outgoing side polarizing plate

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03B 21/14 G03B 21/14 Z H04N 5/74 H04N 5/74 K

Claims (12)

[Claims] 1. A liquid crystal light valve comprising: a liquid crystal panel; and an entrance-side dust-proof glass adhered to an entrance-side surface of the liquid-crystal panel, wherein the incident-side dust-proof glass transmits incident light to the liquid-crystal panel. A liquid crystal light valve that has a lens function of irradiating telecentrically. 2. The liquid crystal light valve according to claim 1, wherein the entrance-side dustproof glass is a convex lens having a curvature on the entrance surface side. 3. The liquid crystal light valve according to claim 2, wherein the convex lens is made of high refractive index glass. 4. The liquid crystal light valve according to claim 2, wherein said convex lens is made of sapphire glass. 5. The liquid crystal light valve according to claim 1, wherein the entrance-side dustproof glass is a gradient index lens. 6. The liquid crystal light valve according to claim 5, wherein the gradient index lens has a flat plate shape. 7. An anti-reflection coating is applied to a surface of the entrance-side dustproof glass on the entrance side.
The liquid crystal light valve according to claim 6. 8. The liquid crystal light valve according to claim 7, wherein the anti-reflection coating is conductive. 9. The liquid crystal light valve according to claim 1, wherein an outer shape of the entrance-side dustproof glass is set to be substantially the same as an outer shape of the liquid crystal panel. . 10. An emission-side dust-proof glass is attached to an emission-side surface of the liquid crystal panel.
A liquid crystal light valve according to claim 9. 11. A liquid crystal projector comprising the liquid crystal light valve according to claim 1. 12. A liquid crystal projector comprising the liquid crystal light valve according to claim 6, wherein an incident side polarizing plate is attached to a surface of the liquid crystal light valve on an incident side of the entrance side dustproof glass.