JPH04121781A - Liquid crystal projector - Google Patents

Abstract

PURPOSE:To obtain a liquid crystal projector which realize natural air cooling, which is miniaturized and which does not impair an acoustic effect by using activated ceramic in order to cool the liquid crystal display device heated by absorbing light when the light from a light source is transmitted through it. CONSTITUTION:White light having illuminance which is several times of solar light is emitted from the light source L and resolved to three primary colors of R, G and B by a total reflecting mirror M and dichroic mirrors DM1 and DM2. Then, it is condensed by a condensor lens C and made incident on the liquid crystal display devices P1, P2 and P3. Besides, it is composed to one full-color video by the mirrors M, DM1 and DM2. Thereafter, it is enlarged and projected on a screen S by a projecting lens (l). At this time, the respective devices P1, P2 and P3 are heated because a liquid crystal panel and a deflecting plate absorb the light when the light from the light source L is transmitted through the respective devices P1, P2 and P3. Then, the heat is absorbed by the heat absorption parts 1b', 1c' and 1d' of cooling bodies 1b, 1c and 1d consisting of the activated ceramic and the devices P1, P2 and P3 are cooled. The heat absorbed by the heat absorption parts is quickly conducted to heat radiation parts 1b'', 1c'' and 1d'' in the respective cooling bodies, exposed to outside air and radiated. Besides, the ambient high temperature of the light source L is absorbed by the cooling body 1a and radiated to the outside air.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention relates to a liquid crystal projector device for projecting an image of a liquid crystal display device onto a screen using light from a light source, and particularly to a liquid crystal projector device having a heat dissipation means. It is something.

<Prior art> In recent years, in order to realize large screens using small and lightweight devices, transmissive color liquid crystal display devices, specifically light pulp, have been used to display the color by irradiating light from a light source on the back side. Color liquid crystal projector devices that project a color image from a liquid crystal display onto a screen are increasingly being used.

An example of the configuration of this color liquid crystal projector device is shown in FIG. L is a light source, M is a total reflection mirror, DMl to DM3 are dichroic mirrors, and dichroic mirrors DMt, DM2 . DM3
are red lights (R) respectively.

Reflects blue light (B) and green light (G). C is a condenser lens, Pl to P3 are liquid crystal display devices, l is a projection lens, and S is a screen.

The above light source is a metal halide lamp (e.g. output 250
White light consisting of W and having an illuminance several times that of sunlight is emitted from the light source, and is separated into the three primary colors of R, G, and B by the total reflection mirror M and dichroic mirrors DMl and DM2. . Each color of light is reflected through a condenser lens C
As the light is focused, the liquid crystal display devices Pl, P2. P3, and the liquid crystal display device Pl, P2. The image formed at P3 is combined into a full-color image by total reflection mirror M and dichroic mirrors DM2 and DM3, and then enlarged and projected onto screen S via projection lens l.

Since the above-mentioned color liquid crystal projector uses three liquid crystal display devices, there is a limit to miniaturization and weight reduction. 2. Description of the Related Art A color liquid crystal projector device that uses a driving type liquid crystal display device and is smaller and lighter in weight is being developed.

In any liquid crystal projector device, the output of the light source must be increased in order to brighten the image on the screen. For this reason, irradiation with strong light causes the temperature of the liquid crystal display device and optical system to rise, causing deterioration of the liquid crystal display device, especially the liquid crystal, color filters, etc. Therefore, forced cooling is performed using a cooling fan to prevent temperature rise. Ta.

<Problem to be solved by the invention> However, in order to improve cooling capacity with conventional cooling fans, using a large cooling fan restricts miniaturization, and increasing the rotation speed with a small cooling fan results in increased noise. Since the noise caused by the rotation of the cooling fan cannot be avoided, it interferes with the sound effects of the video equipment.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a liquid crystal projector device that is equipped with a cooling means that prevents noise, in place of the cooling fan described above.

Means for Solving the Problems> The present invention uses a material that has physical properties that easily absorb heat on the high temperature side and easily release heat on the low temperature side. First, the principles of such materials will be explained.

Heat transfer is the release of thermal energy according to a temperature gradient, and the larger the number and wider the heat paths, the better. This heat path may be considered as an excitation region. In other words, when thermal energy is given to a substance, the atoms and molecules (including ions) that exist there absorb the thermal energy and begin to vibrate, but the vibrational state of these atoms and molecules is different from the normal stable state. A change from a state to an active (unstable) state is called excitation.This vibrational state does not change continuously, but discontinuously, but the more vibrational states there are, the wider the excitation region. it is conceivable that.

This new state is more unstable than the original state, and Uke tries to release the energy it took and return to its original stable state. From this, it is considered that the wider the excitation region is, the more likely it is that heat transfer will occur.

Such customization manifests itself in physical properties that make it easier to absorb heat on the high temperature side and release heat more easily on the lower temperature side.

An example of a material exhibiting such physical properties is active ceramics. If such active ceramics are thermally bonded to a high-temperature part, the active ceramics can effectively dissipate heat from the high-temperature part to the low-temperature part through a very large thermal conduction effect (superthermal conduction effect). The present invention has been made in view of this point, and is a liquid crystal projector that guides light from a light source to a liquid crystal display device and enlarges and projects an image formed on the liquid crystal display device using a projection lens. - A liquid crystal projector device characterized in that an active ceramic is provided in a thermally conductive state around the liquid crystal display device or in a high temperature part of the liquid crystal projector device, and heat is radiated to the outside air through the active ceramic. By doing so, the above objectives will be achieved.

Effect> When the light from the light source passes through the liquid crystal display device, the light is absorbed and turns into heat, which generates heat, causing the temperature of the liquid crystal display device to rise, but the heat from the liquid crystal display device passes through the activated ceramic. and released into the outside air.

In addition, heat from the light source and the portions that receive the light tend to reach high temperatures are also radiated to the outside air via the active ceramic.

<Embodiment> The present invention basically relates to a liquid crystal projector device, which easily absorbs heat on the high temperature side, and is made to closely adhere to the surroundings other than the low temperature element part in a good heat conductive manner to absorb heat. The other parts are exposed to the outside of the liquid crystal color projector device to dissipate heat, and one end of the active ceramic substrate is placed in a space inside the liquid crystal projector device that tends to get hot and does not block the path of light. While it is in contact with the equipment and absorbs heat from it, the other parts are in contact with the air and low-temperature materials outside the liquid crystal projector to lower the temperature inside the liquid crystal projector. .

Embodiments of the liquid crystal projector device of the present invention will be described below.

FIG. 1 is a block diagram showing an embodiment of a liquid crystal projector device of the present invention. In FIG. 1, parts that are equivalent to those of the conventional example shown in FIG. 2 are given the same reference numerals.

The liquid crystal projector device includes a light source consisting of a metal halide lamp and a TPT inside the projector body H.
Active matrix drive type liquid crystal display device Pl,
P2 and P3, and liquid crystal display devices 1 that separate the light from the light source into three primary colors of R, G, and B are provided.

The above light source is formed integrally with the reflecting mirror, and the projector
It is installed on the rear side of the main body H with the irradiation surface facing down.

The liquid crystal display devices Pi, P2 and P3 are R and G.

It consists of a liquid crystal panel for controlling the transmission state of each part of B, and polarizing plates arranged on both sides of the liquid crystal panel, and a control circuit (for controlling and driving the liquid crystal panel).
Not shown. ) and a driver circuit (not shown) are connected to the liquid crystal panel.

The optical means includes a total reflection mirror M, dichroic mirrors DM1 to DM3. Since it has a condenser lens C and is equivalent to the conventional example, detailed explanation will be omitted. Note that F is an ultraviolet and infrared cut filter. Further, the projection lens l is a combination of a convex lens and a concave lens, and is arranged on the front side of the projector main body H.

The cooling device 1 includes a cooling body 1avl made of active ceramic.
It is composed of b, lc and 1d.

The cooling body 1a is a hollow body in the shape of a box or a cylinder with a bottom with one end open, and is attached to the projector main body H so as to be located around the light source,
Note that the side wall portion of the hollow body is the outer wall H of the projector main body H.
The projector is closely attached to the inner surface of the
It is closely attached to the projecting wall H- of the main body H for good thermal conductivity, and the earthen wall portion of the hollow body is exposed to the outside air. Here, cooling body 1
Needless to say, one end of a is open so as not to obstruct the light emitted from the light source.

The cooling bodies 1b, lc, and ld are connected to the liquid crystal display devices Pi, P2.
and a frame-shaped endothermic part 1b' lc that is in close contact with the surrounding part located on the outer periphery of the picture element part in P3 in a good heat conductive manner.
' and ld', and a heat radiation part 1b' integrally extended from this heat absorption part.

It consists of lc' and hild'. Here, the heat radiation portions 1b'lc' and ld'' are attached to the projector main body H in a state exposed to the outside air, and the heat radiation portions 1c1
1 is formed with a fin-like portion having a large outer surface area so as to be in good contact with the air in the space within the projector main body H. And the cooling body 1b.

The endothermic portions 1b' of lc and ld are the liquid crystal display device P'1. In P2 and P3, the wiring part is arranged on the incident surface side where light from the light source enters, and the wiring part is arranged around the liquid crystal display devices Pl, P2 and P3, and the elements arranged in the surrounding part. For example, IC,
This prevents light from the light source from irradiating the connection portion between the wiring portion and the element.

The above active ceramic] a, 1 b+ 1 c and l
d has physical properties that allow it to easily absorb heat on the high temperature side and release heat on the low temperature side. Of course, it immediately absorbs heat from the high-temperature body it comes in contact with, and immediately radiates heat to the other constant-temperature body, such as air.

In the above configuration, white light having an illuminance several times that of sunlight is emitted from the light source, and is separated into three primary colors of R, G, and H by the total reflection mirror M and the dichroic mirrors DMl and DM2. These lights are condensed by a condenser lens C and displayed on the liquid crystal display device P1. P2. P3, and each liquid crystal display device Pi, P2. Total reflection mirror M for the image of P3,
Dichroic mirror DM2. After being combined into one full-color image by the DM 3, this full-color image is enlarged and projected onto the screen S by the projection lens l.

At this time, the light from the light source illuminates the liquid crystal display device P1 + P21.
When passing through P3, the light is absorbed by the liquid crystal panel and polarizing plate and turns into heat, so the liquid crystal display device P 1 + P 2
+P3 generates heat. Here, liquid crystal display device P 19 P
2+The heat around P3 is the cooling body] b+ ICI
The heat is absorbed by the heat absorbing portions 1b'+1c'+ld' of the liquid crystal display devices PI, P2. P3 is cooled. Note that the liquid crystal display devices Pl, P2. P3 is a thin film transistor (similar to the conventional active matrix type).
The substrate on which the TFT), picture element electrodes, and common electrode are formed are made of glass and have good thermal conductivity, and the polarizing plate is also thermally conductive, so the liquid crystal display device P
l, P2. The heat of P3 is transferred to the cooling body 1b through its surrounding area.
, lc, and ld, the heat is well conducted and absorbed by the heat absorbing portions 1b'1c'+1d'.

In this cooling body 1bt Icy ld, the heat absorption part]b
'.

The heat absorbed by 1c'+ld' is transferred to the heat dissipation section 1b'1c'+1
d' and this heat dissipation part 1b' l
c'ld" touches the outside air and radiates heat. In this way, the liquid crystal display devices Pi, P2, and P3 are cooled by cooling bodies 1b+1c
+ ld, heat is radiated to the outside air outside the projector main body H, and the projector body H is cooled.

Furthermore, the temperature of the light source increases due to its own heat generation and the heat generated by the light, raising the temperature of its surroundings. However, the cooling body 1a absorbs heat from the high temperature air around this light source,
Heat is radiated to the outside air from the upper part that is in contact with the outside air. Therefore, the temperature rise around the light source is suppressed, so that overheating of the light source is suppressed and the temperature rise inside the projector main body H is suppressed.

As an embodiment of the present invention, an example using three liquid crystal display devices has been described above, but the present invention can also be applied to a liquid crystal projector device using one liquid crystal display device and similarly cooled. Needless to say.

<Effects of the Invention> According to the present invention, since activated ceramic is used for cooling, natural air cooling is possible and the conventional cooling fan can be omitted, which not only allows for downsizing but also reduces the noise caused by the cooling fan. Therefore, it is possible to provide a practically excellent liquid crystal projector device that does not impair the acoustic effect in audiovisual equipment.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a liquid crystal projector device showing an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional liquid crystal projector device.

Claims (1)

[Claims] 1. In a liquid crystal projector device that guides light from a light source to a liquid crystal display device and enlarges and projects an image formed on the liquid crystal display device using a projection lens, the area around the liquid crystal display device or a high temperature part of the liquid crystal projector device 1. A liquid crystal projector device, characterized in that an active ceramic is provided in a thermally conductive state in the projector, and heat is radiated to the outside via the active ceramic.