JP2560533B2 - LCD projector - Google Patents

Description

The present invention relates to a display device of a liquid crystal projector.

[Conventional technology]

The liquid crystal projector displays an image by using a liquid crystal display panel and enlarges and projects a display image of the liquid crystal display panel on a screen surface by a projection lens. The liquid crystal projector has the following configuration.

That is, FIG. 4 shows the principle of a liquid crystal projector. In FIG. 4, reference numeral 1 denotes a projector case, and a projection lens 2 formed by combining a plurality of optical lenses is provided on the front surface of the case 1. There is. Reference numeral 3 denotes a display device provided in the case 1, and the display device 3 is composed of a transmissive dot matrix liquid crystal display panel 4 arranged so as to face the projection lens 2. The liquid crystal display panel 4 has a pair of polarizing plates 5a and 5b on the light incident side and the light emitting side thereof.
Of the TN (Twisted Nematic) type, and the liquid crystal display panel 4 is connected to the display drive circuit board 6 through a connector 7. Reference numeral 8 denotes a light source device that is provided inside the case 1 and is located behind the liquid crystal display panel 4. The light source device 8 includes a light source lamp 8a and a reflector 8b that reflects the illumination light from the light source lamp 8a toward the liquid crystal display panel 4.
The illumination light from the light enters the liquid crystal display panel 4, and the light transmitted through the liquid crystal display panel 4, that is, the display image of the liquid crystal display panel 4 is condensed on the projection lens 2 by the condenser lens (Fresnel lens in the figure) 9. It is magnified by the projection lens 2 and projected onto the screen s plane arranged in front of the projector.

In other words, this liquid crystal projector includes the liquid crystal display panel 4
Is enlarged and projected on the screen s plane. According to this liquid crystal projector, the display image of the liquid crystal display panel 4 having a small display screen can be greatly enlarged and viewed.

[Problems to be solved by the invention]

However, the liquid crystal projector described above includes the light source device 8
In order to display an image by making the illuminating light from the liquid crystal display panel 4 incident on the liquid crystal display panel 4, the liquid crystal display panel 4 is heated by the heat (infrared component) of the incident light and is emitted from the light source device 8 to the surroundings. The liquid crystal in the liquid crystal display panel 4 rises in temperature due to the heat generated, and the display contrast of the liquid crystal display panel 4 is lowered due to this heat, and a clear image is projected on the screen s surface. Not only is it impossible, but the life of the liquid crystal is also reduced. Therefore, in the liquid crystal projector, the temperature rise of the liquid crystal display panel 4 is suppressed by cooling the inside of the case 1. However, a high-intensity xenon lamp or the like generally used as the light source lamp 8a of the liquid crystal projector is not used. Since a considerable amount of heat is generated, it is not possible to sufficiently suppress the temperature rise of the liquid crystal display panel 4 only by air-cooling the case 1, and the polarizing plates 5a and 5b provided on both sides of the liquid crystal display panel 4 emit light. The temperature of the polarizing plate 5a on the light-incident side is increased considerably by absorbing heat or heat (especially, the temperature of the polarizing plate 5a on the light incident side becomes considerably high). Therefore, the temperature rise of the liquid crystal in the liquid crystal display panel 4 cannot be suppressed to the extent that it is not affected by heat.

The present invention has been made in view of the above situation, and an object thereof is to forcibly cool the liquid crystal display panel to forcibly cool the liquid crystal display panel and the liquid crystal display panel due to the heat of illumination light and the heat radiated from the light source device. The liquid crystal projector is capable of suppressing the temperature rise of the liquid crystal display panel at a low level and preventing the cooling efficiency of the liquid crystal display panel from being lowered due to the temperature rise of the polarizing plate, thereby preventing the display contrast and the life of the liquid crystal from being shortened due to the temperature rise of the liquid crystal. It is to provide a display device.

[Means for Solving Problems] The present invention relates to a display device including a liquid crystal display panel for displaying using a pair of polarizing plates, a light source device for irradiating the liquid crystal display panel with light, and a display for the liquid crystal display panel. In a liquid crystal projector including a projection lens for enlarging and projecting an image on a screen surface, the liquid crystal display panel is provided in close contact with one surface of a cooler filled with a transparent cooling liquid, and the One of the polarizing plates is arranged in close contact with the other side of the cooler.

[Action]

In the liquid crystal projector of the present invention, a liquid crystal display panel is provided in close contact with one surface of a cooler filled with a transparent cooling liquid, and one of the pair of polarizing plates is provided on the other surface side of the cooler. By arranging them in close proximity to each other, it is possible to suppress the temperature rise of the liquid crystal display panel and the polarizing plate due to the heat of the illumination light and the radiant heat from the light source device. It is possible to prevent the life of the polarizing plate from being shortened.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

In the figure, 10 is a display panel cooler for cooling the liquid crystal display panel 23, and 20 is a display unit in which the liquid crystal display panel 23 is housed. The display panel cooler 10 is a thin box-shaped container filled with a transparent cooling liquid 15 such as an ethylene glycol aqueous solution, and the cooler 10 has a frame body 11 having an outer shape sufficiently larger than that of the liquid crystal display panel 23. And a transparent plate (glass plate or acrylic resin plate, etc.) 12 and 1 for closing both sides of the frame body 11.
It has a closed structure consisting of 3 and. The frame 11 has a shape in which a display unit mounting plate 11a having a window portion 14 having an area slightly larger than the display area of the liquid crystal display panel 23 is formed on one surface thereof, and one surface of the frame body 11 is closed. The transparent plate 12 is sized so as to cover the window portion 14 and is bonded to the display unit mounting plate 11a, and the transparent plate 13 that closes the other surface of the frame 11 has substantially the same size as the outer shape of the frame 11. And is adhered to the other surface of the frame body 11.

Further, 16 is a heat pipe that is inserted into the display panel cooler 10 while avoiding the portion corresponding to the window portion 14, and this heat pipe 16 is in a state in which both ends of the heat pipe 16 project outside from both sides of the cooler. It is inserted in the upper part of the cooler 10.
The heat pipe 16 releases the heat absorbed by the cooling liquid 15 in the cooler 10 to the outside of the cooler 10. The central portion of the heat pipe 16 inserted into the cooler is a heat absorbing portion a. Both end portions protruding to the outside of the cooler are radiating portions b, b, and vertical strip-shaped large area radiating fins 17, 17 are provided on the outer periphery of the radiating portions b, b. This heat pipe 1
6 is a metal pipe whose both ends are closed, in which a volatile working fluid (heat transfer medium) is sealed. The entire inner surface of the heat pipe 16 is filled with the working fluid in the heat pipe 16 by capillary action. An asbestos-like wick 16a that leads from the heat radiating portion b side to the heat absorbing portion a side is formed. The working fluid transfers heat by reversible two-phase change of evaporation / condensation. As the working fluid, for example, a fluid having a high latent heat coefficient and excellent permeability such as CFC is used. This working fluid heats up and evaporates by heat exchange with the cooling liquid 15 in the display panel cooler 10 in the heat absorbing portion a of the heat pipe 16, becomes vapor, and rises in the heat pipe 16 as well as in the heat pipe 16. The heat radiating portion b of 16 condenses and liquefies by radiating heat to the outside, and the working fluid liquefied by depriving latent heat permeates the wick 16a and is guided to the heat absorbing portion a again by its capillary phenomenon. The heat pipe 16 guides the working fluid evaporated in the heat absorbing part a to the heat radiating parts b and b at both ends of the heat pipe, and liquefies the working fluid in the heat radiating parts b and b to penetrate the wick 16a again. a
In order to lead to, the center portion is bent to the lowest shape and both end sides are inclined obliquely upward.

On the other hand, the display unit 20 has a liquid crystal display panel on both sides.
The housing 21 having a liquid crystal display panel 23 and its display drive circuit board 25 is housed in an extremely thin case-shaped housing 21 provided with openings 22a and 22b corresponding to 23, and openings 22a and 22b on both sides of the housing 21. Of these, the opening 22a on the cooler mounting surface side is sized so that the transparent plate 12 adhered to the display unit mounting plate 11a of the display panel cooler 10 is inserted therein, and the opening 22b on the opposite side.
Are approximately the same size as the display area of the liquid crystal display panel 23. Further, the display drive circuit board 25 has an opening on the cooler mounting surface side of the housing 21 at the center thereof.
22a has a shape in which an opening 25a having substantially the same size as that of 22a is formed.
Chips 26, 26 are arranged so as to surround the opening 25a. The liquid crystal display panel 23 is a TN type transmissive dot matrix liquid crystal display panel for displaying a television image or the like, and the liquid crystal display panel 23 has its light incident side facing the display panel cooler 10. And a plurality of display panel connection terminals (not shown) arranged in the outer peripheral edge of the circuit board 25 and connected by sheet-shaped flexible connectors 27, 27. Also, 24
Reference numerals a and 24b denote a pair of polarizing plates arranged on the light incident side and the light emitting side of the liquid crystal display panel 23, respectively.
Keep the display panel cooler 10 away from the liquid crystal display panel 23.
It is fixed to the other surface (the outer surface of the transparent plate 13 on the side opposite to the display unit mounting side) by means such as adhesion. The polarizing plate 24b on the emitting side is also arranged apart from the liquid crystal display panel 23, and the polarizing plate 24b on the emitting side is arranged on the outside of the display unit 20 so as to face the opening 22b of the housing 21 thereof. (Circular Fresnel lens) 9 surface is fixed by means such as adhesion. The condenser lens 9 is fixed to a lens attachment plate 28 attached to the housing 21 of the display unit 20.

The liquid crystal display panel 23 fixes the display unit 20 by bringing the display unit 20 into contact with the display unit mounting plate 11a of the display panel cooler 10 and fixing the light incident side panel surface.
The cooling unit 10 is installed on the display unit mounting surface of the cooler 10 in a state of being in contact with the outer surface of the display unit mounting side transparent plate 12.

This display device is arranged in a case of a liquid crystal projector with the display unit 20 side facing the projection lens 2 side and the display panel cooler 10 side facing the light source device side. The light A enters the display panel cooler 10 through the incident side polarization plate 24a, is cooled by heat exchange with the transparent cooling liquid 15, and enters the liquid crystal display panel 23 from the display panel cooler 10. Further, the light transmitted through the liquid crystal display panel 23 becomes image light through the emission side polarization plate 24b, and this image light is condensed on the projection lens 2 by the condenser lens 9 and enlarged on the screen surface by the projection lens 2. Projected.

However, in the display device of the liquid crystal projector, even if the liquid crystal display panel 23 is heated by the heat of the illumination light or the radiant heat from the light source device, the liquid crystal display panel 23 is cooled by the cooling liquid 15 in the display panel cooler 10. The cooling liquid 15 is forcibly cooled by the heat pipe 16 and exchanges heat with the heat pipe 16 while convection in the cooler 10, so that the heat absorbed by the cooling liquid 15 is released to the outside by the heat pipe 16. Coolant 15
It is possible to suppress the temperature rise and keep the cooling efficiency of the liquid crystal display panel 23 by the display panel cooler 10 always high. Moreover, in the above display device, the liquid crystal display panel 23
Is provided on the projection lens side of the display panel cooler 10, the illumination light from the light source device can be cooled by heat exchange with the cooling liquid 15 in the cooler 10 and then incident on the liquid crystal display panel 23. Therefore, the temperature rise of the liquid crystal display panel 23 due to the heat of the illumination light can be suppressed low. Further, in the display device, since the polarizing plate 24a on the light incident side of the liquid crystal display panel 23 is provided on the light source device side of the display panel cooler 10 apart from the liquid crystal display panel 23, the incident side polarizing plate 24a is Even if light or heat is absorbed and the temperature is raised, the heat is not transmitted to the liquid crystal display panel 23, and the incident side polarizing plate 24a is also cooled by the display panel cooler 10 to make the incident side polarizing plate 24a.
It can also prevent overheating of a. Further, in this display device, since the emission side polarization plate 24b of the liquid crystal display panel 23 is also arranged apart from the liquid crystal display panel 23, this emission side polarization plate
Even if 24a absorbs light or heat to raise the temperature, the heat is not transferred to the liquid crystal display panel 23. Therefore, according to this display device, while suppressing the temperature rise of the liquid crystal display panel 23 due to the heat of illumination light and the radiant heat from the light source device,
Since it is possible to prevent the cooling efficiency of the liquid crystal display panel 23 from being lowered due to the temperature rise of the polarizing plates 24a and 24b, it is possible to prevent the display contrast from being lowered due to the temperature rise of the liquid crystal in the liquid crystal display panel 23 and project a clear image on the screen surface. In addition, the life of the liquid crystal can be prevented from being shortened. Further, in the above embodiment, the display drive circuit board 25 is provided in the display unit 20 together with the liquid crystal display panel 23, and the display unit 20
Since it is attached to the display panel cooler 10, not only the liquid crystal display panel 23 but also the display drive circuit board 25 can be cooled by the display panel cooler 10 to prevent thermal destruction of the display drive circuit.

In the above embodiment, the exit side polarizing plate 24b of the liquid crystal display panel 23 is also arranged apart from the liquid crystal display panel 23, but the temperature rise due to the absorption of light and heat of the exit side polarizing plate 24b is relatively large. Since it is small, the exit side polarization plate 24b may be provided in contact with the liquid crystal display panel 23. Further, in the above embodiment, the liquid crystal display panel 23 is provided on the projection lens side of the display panel cooler 10, but the liquid crystal display panel 23 may be provided on the light source device side of the display panel cooler 10, in which case Is
The incident side polarization plate 24a of the liquid crystal display panel 23 may be provided separately from the display panel cooler 10 and the liquid crystal display panel 23 on the light source device side.

〔The invention's effect〕

A liquid crystal projector of the present invention includes a display device including a liquid crystal display panel for displaying using a pair of polarizing plates, a light source device for irradiating the liquid crystal display panel with light, and a display image of the liquid crystal display panel on a screen surface. In a liquid crystal projector having a projection lens for enlarging and projecting, the liquid crystal display panel is provided in close contact with one surface of a cooler filled with a transparent cooling liquid, and one of the pair of polarizing plates is provided. Since it is arranged closely to the other surface side of the cooler, it is possible to suppress the temperature rise of the liquid crystal display panel and the polarizing plate due to the heat of the illumination light and the radiant heat from the light source device,
It is possible to prevent a decrease in display contrast due to temperature rise of the liquid crystal and a decrease in life of the liquid crystal and the polarizing plate.

[Brief description of drawings]

FIG. 1 is a vertical side view of a display device showing an embodiment of the present invention, FIGS. 2 and 3 are front views and plan views of the display device, and FIG. 4 is a principle configuration diagram of a conventional liquid crystal projector. is there. 2 ... Projection lens, 9 ... Condensing lens, 10 ... Display panel cooler, 15 ... Coolant, 16 ... Heat pipe, 23 ...
Liquid crystal display panel, 24a …… Injection side polarization plate, 24b …… Exit side polarization plate, 25 …… Display drive circuit board.

Claims (2)

(57) [Claims] 1. A display device comprising a liquid crystal display panel for displaying using a pair of polarizing plates, a light source device for irradiating the liquid crystal display panel with light, and a display image of the liquid crystal display panel enlarged and projected on a screen surface. A liquid crystal projector having a projection lens for providing a liquid crystal display panel in close contact with one surface of a cooler filled with a transparent cooling liquid, wherein one of the pair of polarizing plates is provided. A liquid crystal projector, characterized in that it is arranged in close contact with the other side of the cooler. 2. The liquid crystal projector according to claim 1, wherein the other polarizing plate is also arranged apart from the liquid crystal display panel.