JPH1138409A - Reflection liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformize a temp. distribution of a display area of a reflection liquid crystal display device and to efficiently dissipate the heat caused by light absorption of incident light to the outside. SOLUTION: This device is provided with the structure integrating the reflection liquid crystal display device 1 with a heat exchange medium 2, and the heat exchange medium 2 consists of metallic material with excellent heat conductivity, and is nearly the same size as the reflection liquid crystal display device 1, and its thickness is about 1-2 mm. It is stuck to a reflection substrate 3R. Thus, the temp. distribution of the display area is uniformized, and the heat caused by the reflection liquid crystal display device 1 is absorbed to be dissipated to the outside. Deterioration in display quality is prevented by this heat dissipation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling structure for a reflection type liquid crystal display device incorporated in a projector or the like.

[0002]

2. Description of the Related Art In a reflection type liquid crystal display device, picture element electrodes are arranged in a matrix, and a driving voltage is independently applied to each picture element electrode to control the optical characteristics of the liquid crystal and to enter the liquid crystal display apparatus. The reflected light is reflected by a reflection plate included in the liquid crystal display device to display images, characters, and the like. Among them, the active matrix driving method uses TFT, M
By installing a switching element such as IM,
It enables high image quality display such as high contrast and high speed response.

Since a reflection type liquid crystal display device using such a switching element does not emit light by itself, it is necessary to input light from the outside in order to display images and characters.

FIG. 9 shows a configuration in which a reflection type liquid crystal display device is incorporated in a projector. The illumination means 21 is composed of a lamp 22 as a light source and a concave mirror 23,
i is a polarizing plate, 32 is a polarizing beam splitter, 28o is a polarizing plate, 27 is a reflective liquid crystal display device, 29 is a field lens, 30 is a projection lens, and 31 is a screen.

[0005] The light beam from the illuminating means 21 is incident on a polarizing beam splitter 32 via a polarizing plate 28i. Of this light flux, the P-polarized light component passes through the polarizing beam splitter 32, and the S-polarized light component is reflected in the side direction and enters the reflection type liquid crystal display device 27. In the reflection type liquid crystal display device 27, the S-polarized light component is modulated and reflected. Therefore, the P-polarized light component included in the reflected light is reflected by the polarization beam splitter 3.
2 can be transmitted and projected on a screen 31 via a field lens 29 and a projection lens 30 to display an image.

[0006]

Since the reflection type liquid crystal display device does not emit light by itself, it is necessary to input light from the outside. Part of the incident light is absorbed by the substrate of the reflective liquid crystal display device, the liquid crystal, a reflector that reflects light, and the like, becomes heat, and raises the temperature of the reflective liquid crystal display device.

In particular, when a reflective liquid crystal display device is incorporated in a projector, the reflective liquid crystal display device is illuminated by a lamp that emits light of high illuminance such as a metal halide lamp. It has become. Further, when an illuminance difference is generated between the center of the display area and the end face of the display area of the liquid crystal display device, an in-plane temperature difference is generated due to a difference in generated heat, resulting in deterioration of display quality such as contrast.

Light incident on a reflection type liquid crystal display device is absorbed by a polarizing plate, a liquid crystal, a reflection plate, etc. and becomes heat. The generated heat heats the reflection type liquid crystal display device, affects optical characteristics such as transmittance of glass and liquid crystal, and also changes operating characteristics of the switching element. As a result, the display quality such as contrast and the reliability of the liquid crystal display device are reduced.

Conventionally, as a structure for equalizing the in-plane temperature difference of a liquid crystal display device, a structure in which a transparent heat exchange medium is integrated in a display area of the liquid crystal display device and heat generated in the liquid crystal display device is radiated to the outside. There is. In this method, since the image display area is covered with the transparent heat exchange medium, materials that can be used for the heat exchange medium are limited. Furthermore, when light passes through a transparent heat exchange medium, display quality is degraded due to light absorption, reflection, and birefringence.

There is a method of covering the periphery of the display area with a heat exchange medium. However, since the image display area on which light is incident cannot be covered with the heat exchange medium, heat at the center of the display area is radiated. And the temperature distribution between the central part and the peripheral part of the image display area tends to be different.

In a projector using a transmissive liquid crystal display device, as a method of radiating heat generated in the liquid crystal display device to the outside, a liquid crystal covering a peripheral portion of an image display area of the transmissive liquid crystal display device with a heat exchange medium is used. The display device is disclosed in
No. 211390. Japanese Patent Application Laid-Open No. 8-146378 discloses a liquid crystal display device in which a transparent heat exchange medium is integrated in an image display area of the liquid crystal display device.

In order to cool a lamp provided in the projector, a lamp cooling fan is provided in the main body of the projector. The liquid crystal display device is cooled by using the ventilation of the lamp cooling fan. Since the lamp cooling fan cools both the lamp and the liquid crystal display device, it is necessary to increase the air flow of the lamp cooling fan. As a result, there is a problem that the shape and noise of the lamp cooling fan increase. Since high-temperature exhaust is exhausted from the projector main body, it is uncomfortable for a person near the exhaust port of the projector.

[0013]

According to the present invention, there is provided a reflective liquid crystal display device in which liquid crystal is sealed between a pair of substrates and which reflects light incident from the outside to display images, characters, and the like. It is characterized in that a heat exchange medium having high heat conductivity is integrated with the reflection substrate of the apparatus.

Further, the present invention is characterized in that the heat exchange medium covers at least the reflective substrate.

Further, the present invention is characterized in that the heat exchange medium is made of a material having a thermal conductivity larger than that of the substrate of the reflection type liquid crystal display device.

Further, the present invention is characterized in that the heat exchange medium has a heat radiating means for radiating heat generated in the liquid crystal display device to the outside.

Further, the present invention is characterized in that the reflection type liquid crystal display device according to at least one of claims 1 to 4 is used for a projection type liquid crystal display device.

The operation of the above configuration will be described. By integrating a heat exchange medium having high heat conductivity with the reflective substrate of the reflective liquid crystal display device, it is possible to eliminate the temperature gradient in the display area of the reflective liquid crystal display device. Further, the heat exchange medium can absorb the heat generated in the reflection type liquid crystal display device and radiate the heat to the outside. This heat dissipation can prevent the display quality from deteriorating.

Further, since the reflective substrate does not directly affect the display function, various cooling methods can be used for the shape and structure of the heat exchange medium.

Since the heat exchange medium covers at least the reflection substrate, it can absorb heat generated in the reflection type liquid crystal display device and radiate it to the outside. This heat dissipation can prevent the display quality from deteriorating.

The heat exchange medium is made of a material having a thermal conductivity larger than that of the substrate of the reflection type liquid crystal display device, thereby absorbing heat generated in the reflection type liquid crystal display device and radiating heat to the outside. can do. With this heat dissipation,
The display quality can be prevented from lowering.

Since the heat exchange medium has heat radiating means for absorbing the heat generated in the liquid crystal display device and radiating the heat to the outside, the heat generated in the reflective liquid crystal display device can be radiated to the outside. This heat dissipation can prevent the display quality from deteriorating.

By using a reflection type liquid crystal display device in which a heat exchange medium is integrated as a projection type liquid crystal display device, the reflection type liquid crystal display device does not affect display even at high temperature conditions. The temperature rise of the liquid crystal display device can be suppressed. In addition, the amount of air blown by the lamp cooling fan provided in the main body of the projector can be reduced by the heat radiation effect of the heat exchange medium. Therefore,
The shape of the lamp cooling fan can be reduced, and the noise can be reduced. The amount of high-temperature exhaust can also be reduced, which can alleviate discomfort to those who are near the exhaust of the projector.

[0024]

Embodiments of the present invention will be described below.

(Embodiment 1) FIG. 1 is a side sectional view of Embodiment 1. FIG. FIG. 2 shows a perspective view of the first embodiment as viewed obliquely from the front. 1 and 2, the first embodiment has a structure in which a reflective liquid crystal display device 1 and a heat exchange medium 2 are integrated. The reflective liquid crystal display device 1 holds a liquid crystal 4 between a pair of substrates 3. A reflection plate 5 is formed on one substrate 3R of the reflection type liquid crystal display device 1, and an image is displayed by reflecting incident light on the reflection plate 5. 3R is hereinafter referred to as a reflective substrate. The outside of the substrate 3 on which light is incident is defined as the display surface 6, and the surface opposite to the surface of the reflective substrate 3 </ b> R on which the switching elements and the liquid crystal are formed is defined as the back surface 7. 8 is the display surface 6
Is a display area.

On the other hand, the heat exchange medium 2 is integrated with the reflection substrate 3R on the back surface 7 of the reflection type liquid crystal display device 1, and is made of a material having good heat conductivity. By forming the heat exchange medium 2 on the back surface 7, the substrate 3R of the reflection type liquid crystal display device 1 is provided.
It is possible to cover the whole with the heat exchange medium 2 of a non-transparent material. The heat exchange medium 2 may be at least as large as or larger than the reflective liquid crystal display device 1.

Since the reflection type liquid crystal display device 1 displays an image by making light incident on the display area 8 of the display surface 6, the back surface 7 does not affect the display image at all. Therefore, it is possible to integrate the non-transparent heat exchange medium 2 with good thermal conductivity into the reflective substrate 3R on the back surface 7. The heat exchange medium 2 absorbs heat generated in the reflection type liquid crystal display device 1 and cools the reflection type liquid crystal display device 1, and at the same time, efficiently radiates heat to the outside of the reflection type liquid crystal display device 1. This heat dissipation can prevent the display quality from deteriorating. Further, by disposing the heat exchange medium 2 in close contact with the reflective liquid crystal display device 1, the temperature gradient generated in the display area 8 can be reduced.

In the first embodiment, as the heat exchange medium 2 integrated with the back surface 7, a metal having a higher thermal conductivity than glass, which is a material of the substrate 3, such as copper or aluminum, is used. The thermal conductivity of the glass is about 1.0 W / mK,
Copper has a thermal conductivity of about 390 W / m · K, and aluminum has a thermal conductivity of about 220 W / m · K. The shape of the heat exchange medium 2 is almost the same size as the reflection type liquid crystal display device 1,
The thickness is a flat plate of about 1 to 2 mm.

As a method of integrating the reflection type liquid crystal display device 1 and the heat exchange medium 2, they were adhered using an epoxy adhesive (thermal conductivity: about 1.4 W / m · K). The material for bonding the reflection type liquid crystal display device 1 and the heat exchange medium 2 is thermally stable and has a certain heat conductivity under long-term use,
What is necessary is that the bonding between the two materials is always maintained.

Since the heat exchange medium 2 integrated with the back surface 7 does not directly affect the displayed image, the size, thickness, color, etc., can be freely selected according to the purpose of use and the shape of the reflective liquid crystal display device. can do.

By replacing the reflection type liquid crystal display device 27 of FIG. 9 with the reflection type liquid crystal display device 1 in which the heat exchange medium 2 made of a metal flat plate is integrated, the projector can be assembled as shown in FIG. Is also possible.

The temperature of the reflection type liquid crystal display device 1 can be controlled by the heat exchange medium 2 so as to be within an appropriate temperature (for example, 60 ° C.). Therefore, the liquid crystal operates normally, and the temperature distribution in the display area can be made uniform, and the generated heat can be absorbed and radiated to the outside. This heat dissipation can prevent the display quality from deteriorating.

Further, due to the heat radiation effect of this heat exchange medium,
The amount of air blown by the lamp cooling fan provided in the main body of the projector can be reduced. Therefore, the shape of the lamp cooling fan can be reduced, and the noise can be reduced. The amount of high-temperature exhaust can also be reduced, which can alleviate discomfort to those who are near the exhaust of the projector.

(Embodiment 2) FIG. 3 shows a side sectional view of Embodiment 2. In FIG. As a method of improving the heat radiation effect of the heat exchange medium 2, a heat sink (heat sink) having a surface area increased by forming irregularities on the surface of the heat exchange medium 2 is integrated with the reflective liquid crystal display device 1. The method of integration is the same as in the first embodiment.

By replacing the reflection type liquid crystal display device 27 in FIG. 9 with the reflection type liquid crystal display device 1 in which the heat exchange medium 2 is integrated, it is possible to incorporate the reflection type liquid crystal display device in a projector as shown in FIG.

With the heat exchange medium 2, the temperature of the reflection type liquid crystal display device can be controlled to be within an appropriate temperature. Therefore, the liquid crystal operates normally, and the temperature distribution in the display area can be made uniform, and the generated heat can be absorbed and radiated to the outside. This heat dissipation can prevent the display quality from deteriorating.

(Embodiment 3) FIG. 4 is a rear view of the embodiment 3 and FIG. A heat pipe 9 type radiator is used as the heat exchange medium 2 integrated with the back surface 7 of the reflection type liquid crystal display device 1. A liquid or a gas is sealed and circulated as the refrigerant 10 inside the heat pipe 9, and the heat generated in the reflection type liquid crystal display device 1 is absorbed by the refrigerant 10 in the heat pipe 9, and the heat is generated outside the reflection type liquid crystal display device 1. Dissipate heat. Embodiment 1 is a method for integration.
Is the same as

By replacing the reflection type liquid crystal display device 27 in FIG. 9 with the reflection type liquid crystal display device 1 in which the heat exchange medium 2 is integrated, it is possible to incorporate the reflection type liquid crystal display device in a projector as shown in FIG.

With the heat exchange medium 2, the temperature of the reflection type liquid crystal display device 1 can be controlled to be within an appropriate temperature. Therefore, the liquid crystal operates normally, and the temperature distribution in the display area can be made uniform, and the generated heat can be absorbed and radiated to the outside. This heat dissipation can prevent the display quality from deteriorating.

(Embodiment 4) FIG. 6 is a rear view of the embodiment 4, and FIG. The fan 11 is integrated with the heat exchange medium 2 to directly send air to the reflection type liquid crystal display device 1 and the heat exchange medium 2 for cooling. The method of integrating the fan 11 and the heat exchange medium 2 is the same as in the first embodiment.

The heat exchange medium 2 has a structure provided with ventilation holes or a structure provided with irregularities in order to easily radiate heat generated in the liquid crystal display device to the outside.

By replacing the reflection type liquid crystal display device 27 in FIG. 9 with the reflection type liquid crystal display device 1 in which the heat exchange medium 2 and the fan 11 are integrated, it is also possible to incorporate the reflection type liquid crystal display device in a projector as shown in FIG. It is.

For example, by attaching a temperature sensor to the surface of the heat exchange medium 2 and linking it with the fan 11, the temperature of the reflective liquid crystal display device 1 can be controlled to be within an appropriate temperature. Therefore, the liquid crystal operates normally, and the temperature distribution in the display area can be made uniform, and the generated heat can be absorbed and radiated to the outside. This heat dissipation can prevent the display quality from deteriorating.

The number and size of the integrated fans can be changed according to the size of the reflection type liquid crystal display device, and the temperature of the reflection type liquid crystal display device can be kept constant by adjusting the air volume of the fan. .

(Embodiment 5) FIG. 8 is a schematic configuration diagram of Embodiment 5. As the heat exchange medium 2 to be integrated with the back surface 7, a heat pipe type radiator 13 is used. A sealed container 19 made of metal and having high thermal conductivity is added to the reflection type liquid crystal display device 1, and a liquid and an inert gas or air which are easily evaporated are sealed in the sealed container 19. The metal absorbs the heat of the reflection type liquid crystal display device 1 and conducts the heat to the liquid inside. The heat is used as heat of vaporization when the liquid evaporates, and the reflection type liquid crystal display device 1 is cooled. The vaporized liquid rises inside the sealed container 19, radiates heat of vaporization to the outside at the upper portion of the sealed container 19, and then condenses and returns to the lower portion of the sealed container 19 by gravity. The radiating fins 12 are provided outside the sealed container 19 in order to further facilitate heat radiation. As the liquid sealed in the sealed container 19, for example, a liquid such as water is used so that the reflection type liquid crystal display device 1 can be maintained at an appropriate temperature. With this structure, the reflective liquid crystal display device 1 can be cooled without using a circulation member such as a pump.

By replacing the reflection type liquid crystal display device 27 in FIG. 9 with the reflection type liquid crystal display device 1 in which the radiator 13 is integrated, it is possible to incorporate the reflection type liquid crystal display device in a projector as shown in FIG.

The radiator 13 can control the temperature of the reflection type liquid crystal display device 1 to be within an appropriate temperature. Therefore, the liquid crystal operates normally, and the temperature distribution in the display area can be made uniform, and the generated heat can be absorbed and radiated to the outside. This heat dissipation can prevent the display quality from deteriorating.

[0048]

The heat exchange medium is composed of a material having good heat conductivity or a radiator including a heat sink, a heat pipe, a fan, etc., and the heat exchange medium is integrated with the back surface of the reflection substrate to form a reflection type liquid crystal. The temperature gradient in the display area of the display device can be eliminated. Further, heat generated in the reflection type liquid crystal display device can be absorbed and radiated to the outside. This heat dissipation can prevent the display quality from deteriorating.

Further, since the heat exchange medium is bonded to the surface opposite to the surface on which an image is displayed, it is possible to use a non-transparent material such as a metal or a radiator.

By using a reflection type liquid crystal display device in which a heat exchange medium is integrated as a projection type liquid crystal display device, the reflection type liquid crystal display device does not affect display even at high temperature conditions. The temperature rise of the liquid crystal display device can be suppressed. In addition, the amount of air blown by the lamp cooling fan provided in the main body of the projector can be reduced by the heat radiation effect of the heat exchange medium. Therefore,
The shape of the lamp cooling fan can be reduced, and the noise can be reduced. The amount of high-temperature exhaust can also be reduced, which can alleviate discomfort to those who are near the exhaust of the projector.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a first embodiment.

FIG. 2 is a perspective view of the first embodiment.

FIG. 3 is a side sectional view of a second embodiment.

FIG. 4 is a back view of the third embodiment.

FIG. 5 is a side sectional view of a third embodiment.

FIG. 6 is a rear view of the fourth embodiment.

FIG. 7 is a side sectional view of a fourth embodiment.

FIG. 8 is a schematic configuration of a fifth embodiment.

FIG. 9 is a schematic configuration diagram of a projector using a reflective liquid crystal display device.

[Explanation of symbols]

 Reference Signs List 127 reflective liquid crystal display device 2 heat exchange medium 3 substrate 3R reflective substrate 4 liquid crystal 5 reflective plate 6 display surface 7 back surface 8 display area 9 heat pipe 10 refrigerant 11 fan 12 radiating fin 13 radiator 19 sealed container

Claims (5)

[Claims] 1. A reflection type liquid crystal display device in which liquid crystal is sealed between a pair of substrates and reflects light incident from outside to display images, characters, and the like. Reflective liquid crystal display device characterized by integrating a high heat exchange medium. 2. The reflection type liquid crystal display device according to claim 1, wherein the heat exchange medium covers at least the reflection substrate. 3. The reflective liquid crystal display according to claim 1, wherein the heat exchange medium is made of a material having a thermal conductivity higher than that of a substrate of the reflective liquid crystal display device. apparatus. 4. The reflection type liquid crystal display device according to claim 1, wherein the heat exchange medium has a heat radiating means for radiating heat generated in the liquid crystal display device to the outside. 5. The reflection type liquid crystal display device according to claim 1, wherein the reflection type liquid crystal display device according to claim 1 is used for a projection type liquid crystal display device.