JPH10319379A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent temperature rise, to prevent dust and to make a device small in size and compact by putting the incident and emitting surface sides of a liquid crystal display element in hermetically sealed spaces and further connecting them to a wall surface cooling means being other part of the hermetically sealed space. SOLUTION: Since a display picture element area comes in contact with only the hermetically sealed spaces 2 and 3 surrounded by the liquid crystal display element 1, an incident side transparent member 4, an emitting side transparent member 5, a holding frame 6 and a panel plate 7, it does not touch the dust of outside air. A part of heat generated in the element 1 is conducted to the frame 6 and the plate 7 due to heat conduction and transferred to the outside of a liquid crystal display part 15. The rest of the heat is exchanged with gas inside the spaces 2 and 3 and transferred. Namely, a cooling fan 26 exchanges the heat inside the display part 15 consisting of the frame 6, the plate 7 and the members 4 and 5 so as to cool the display part 15. Therefore, the prevention of dust is made compatible with heat radiation and further the entire device is miniaturized by miniaturizing the display part 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection apparatus for projecting an image on a screen using a liquid crystal display device or the like.
For example, the present invention relates to a video display device such as a liquid crystal projector device, a liquid crystal television, and a projection display device.

[0002]

2. Description of the Related Art There is known a projection type image display apparatus such as a liquid crystal projector which illuminates a display element such as a liquid crystal panel with light from a light source such as a light bulb and projects an image on the liquid crystal panel in an enlarged manner.

In this type of display device, light from a light source is adjusted by changing the density of each pixel by a liquid crystal display element, and the light is projected on a screen or the like. The light emitted from the light source is absorbed by the liquid crystal display element and its surrounding optical elements and becomes heat, except for the finally projected light. For this reason, the liquid crystal display element and its vicinity are heated.

A liquid crystal display element is generally composed of a semiconductor driving element and an optically functional material such as liquid crystal, and in order to operate normally, the temperature is maintained at a predetermined temperature (for example, 60 ° C.) or lower. There is a need. For this reason, conventionally, various methods have been applied to cooling the liquid crystal display element.

In addition, since the projection optical system focuses on the image plane of the liquid crystal display element, foreign matter such as dust adhering near the liquid crystal display element is directly enlarged and projected as a shadow. Therefore, various methods for preventing dust in the vicinity of the liquid crystal display element have been applied.

First, as a conventional technique relating to cooling of a liquid crystal panel, there is known an example described in Japanese Patent Application Laid-Open No. 1-169424. In this conventional technique, liquid is sealed in a cooling box integrated with a liquid crystal panel, which is a liquid crystal display element, and the liquid circulates and cools the heat generated by the liquid crystal panel, and radiates heat to the outside of the cooling box. is there. By doing so, there is an effect that the display surface of the liquid crystal panel through which light is transmitted is cooled, and that dust from the outside does not enter the vicinity of the panel.

However, in this prior art, the handling of a cooling liquid involves a series of liquid handling such as liquid leakage, generation of air bubbles, and shortage of liquid due to evaporation due to expansion and contraction due to temperature change and aging. However, there has been a problem that the conventional technology has not been sufficiently recognized.

The prior art relating to a method for achieving both dust prevention and heat radiation without using a liquid is disclosed in Japanese Patent Laid-Open No. 7-15200.
An example described in Japanese Patent Publication No. 9 is known. In this conventional technique, a liquid crystal panel, which is a transmissive liquid crystal display element, is placed in a closed space, and the air in the closed space is forcibly circulated to radiate heat generated by the liquid crystal panel. The heat is exchanged with the air outside the enclosed space to release the heat. In this way, both dust prevention and heat dissipation can be achieved. However, in this conventional technique, it has not been sufficiently recognized that since the air is forcibly circulated in the closed space, the closed space itself becomes large, and the device itself becomes large in size.

That is, it is necessary to achieve both the prevention of dust and the heat radiation of the liquid crystal panel, and to reduce the size and size of the entire device.

[0010]

To summarize the above problems in the prior art, the problem is how to dissipate heat and dust in a liquid crystal display element such as a liquid crystal panel, and furthermore, a method that can reduce the size of the device. Is an issue.

An object of the present invention is to provide a liquid crystal display device which can prevent a rise in temperature, prevent dust, and can be reduced in size and size.

[0012]

According to the present invention, the liquid crystal display element is surrounded by a sealed space, and the wall surface constituting the sealed space is radiated and cooled. Since the liquid crystal display element placed in the closed space does not touch the outside dust, the dust does not cause a shadow on the image. Further, the heat generated by the liquid crystal display element is radiated by air convection in the enclosed space, and further cooled by cooling / radiating means on the wall surface.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the apparatus according to the present invention.

FIG. 1 is a cross-sectional view showing an example of the configuration of each part of a liquid crystal display unit according to a first embodiment of the present invention. FIG. 2 shows the internal configuration of the first embodiment of the present invention. FIG. 3 is a perspective view showing an appearance of a closed space according to the first embodiment of the present invention.

1 is a liquid crystal display element, 1a is a liquid crystal display element 1.
4 is an incident side transparent member, 5 is an emission side transparent member, 2 is a sealed space surrounded by the liquid crystal display element 1, the incident side transparent member 4 and the holding frame 6, and 6 is holding of the liquid crystal display element 1. A frame 7 is a panel plate for holding and fixing the holding frame 6 integrally around the liquid crystal display element. A frame 3 is surrounded by the liquid crystal display element 1, the emission side transparent member 5, the holding frame 6 and the panel plate 7. The closed space 15 is a liquid crystal display unit having these configurations. Reference numeral 26 denotes a cooling fan that generates air convection for cooling. Numeral 90 indicates a light incident direction.

Incoming side transparent member 4 and outgoing side transparent member 5
Is formed of a translucent material such as transparent glass.
An antireflection film may be formed on the surfaces of the incident side transparent member 4 and the exit side transparent member 5.

The holding frame 6 and the panel plate 7 are made of, for example, a metal such as Fe, Cu, Al, or Mg and a material containing them and having excellent heat conductivity. Holding frame 6
The panel plate 7 is provided with a substantially rectangular opening, and does not block the optical path to the display pixel area 1a.

The display pixel area 1a is in contact with only the closed spaces 3 and 4 surrounded by the liquid crystal display element 1, the incident side transparent member 4, the exit side transparent member 5, the holding frame 6, and the panel plate 7, so that the outside air Never touch. Therefore, no dust is present in the vicinity of the focal point area of the projection optical system with respect to the liquid crystal display element 1, and therefore, no shadow due to dust is generated in the image.

The heat generated in the liquid crystal display element 1 is partially transmitted to the peripheral portion by contact heat conduction, and the remaining part is transmitted to the closed spaces 2 and 3.
The heat is exchanged with the gas inside and transmitted. In the heat conduction by the contact, the heat is transmitted to the holding frame 6 and the panel plate 7, and is transmitted to the outside of the liquid crystal display unit 15. The heat that has exchanged heat with the gas generates natural convection, and is transferred to the holding frame 6 and the inner wall surface of the panel plate 7. The holding frame 6 and the panel plate 7 have a role of radiating the transmitted heat to the outside of the closed space. The flow path of the convection air for cooling from the cooling fan 26 is arranged along the holding frame 6 and the panel plate 7 and includes the holding frame 6 and the panel plate 7, the incident side transparent member 4, and the emission side transparent member 5. The liquid crystal display unit 15 is cooled by exchanging heat inside the liquid crystal display unit 15. Although not shown in the figure, a radiation fin may be provided on at least one of the outer walls of the holding frame 6 and the panel plate 7. In this case, it is desirable that the radiation fins are along the flow path of the cooling air convection from the cooling fan 26.

As a result, the heat generated in the liquid crystal display element 1 is transmitted through the holding frame 6 and the panel plate 7 to the liquid crystal display section 1.
5 is radiated to the outside.

In this way, both dust prevention and heat dissipation can be achieved.
Further, the overall size of the device can be reduced by reducing the size of the liquid crystal display.

The liquid crystal display section 15 of the present invention having the above-described structure.
The function of the liquid crystal projector having the above will be described with reference to FIG.

FIG. 4 is a schematic diagram showing the entire optical system of the liquid crystal projector according to the embodiment of the present invention. In FIG.
Reference numeral 30 denotes a light source such as a metal halide lamp, and 31 denotes a light source 30.
Reflectors for condensing the emitted light in a certain direction, 32, 3
Reference numeral 3 denotes a multi-lens in which many cell lenses are gathered.
Reference numerals 34 to 39 denote separation optical systems, which are a group of mirrors for separating light into three primary color RGB components. 40R, 40G, and 40B are condenser lenses for condensing each of the RGB components on the liquid crystal display element, and 41R, 41G, and 41B are incident-side polarizers.
5R, 15G, and 15B are the liquid crystal display units 15 described above. Reference numeral 42 denotes a combining optical system that combines the RGB components separated by the separating optical system. 43 is a projection lens, and 44 is a screen. In the liquid crystal projector having the above-described configuration, light emitted from the light source 30 is condensed on the multi-lenses 32 and 33 by the reflecting mirror 31 and enters the mirror group of the separation optical system. The multi-lenses 32 and 33 have a function of uniformly entering light to every corner of the display pixel region 1a of the liquid crystal display element 20, and have a function of making the illuminance uniform at any place on the screen 44. The light that has passed through the multi-lens is decomposed into RGB components by separation optical systems 34 to 39,
The light enters the liquid crystal display units 15R, 15G, and 15B via the condenser lenses 40R, 40G, and 40B and the incident-side polarizers 41R, 41G, and 41B. In the liquid crystal display unit, the light of each RGB component adjusted by changing the shading of each pixel is:
After being combined in the combining optical system 42, the projection lens 43
, Image information is displayed on the screen 44.

FIG. 5 is a sectional view showing an example of the configuration of each part of the liquid crystal display unit according to the second embodiment of the present invention.
FIG. 7 is a perspective view showing an internal configuration of a second embodiment of the present invention, and FIG. 7 is a perspective view showing an external appearance of a closed space in the second embodiment of the present invention.

1 is a liquid crystal display element, 1a is a liquid crystal display element 1.
A display pixel area, 4 is an incident side transparent member, 2 is a sealed space surrounded by the liquid crystal display element 1 and the incident side transparent member and the holding frame 52, 50 is a heat pipe, 51 is a radiation fin, 52
Denotes a holding frame of the liquid crystal display element 1, and 15 denotes a liquid crystal display section including the liquid crystal display element 1, the sealed space 2, the incident side transparent member 4, and the holding frame 52. Reference numeral 26 denotes a cooling fan that generates air convection for cooling. Numeral 90 indicates a light incident direction.

The second embodiment of the present invention is different from the first embodiment in that the holding frame 52 has a heat pipe 5
0 is disposed so as to be contact-fixed or integrated, and the holding frame 52 is cooled by heat transfer to the heat pipe 50. At least a part of the heat pipe 50 is disposed in the anti-gravity direction of the holding frame 52, and a heat radiating unit of the heat pipe 50 is provided here. In FIGS. 5 to 7, heat radiating fins 51 are contact-fixed or integrated as heat radiating means of the heat pipe 50.

In FIG. 5, the heat fins 51 are shown as being orthogonal to the cooling air convection direction for the sake of explanation.
Actual radiating fins are arranged in parallel (at right angles to the drawing) in the direction of convection of cooling air as shown in FIG. In addition, the heat radiating means of the heat pipe 50 may be a heat transfer element (for example, a Peltier element) or a combination of a heat transfer element and a radiating fin. Further, among other components of the device in which the liquid crystal display unit 15 is used, the liquid crystal display unit 15 may be in contact with and fixed to a component having a lower temperature than the liquid crystal display unit 15.

In the second embodiment of the present invention, the incident surface side of the display pixel area 1a is in contact with the sealed space 2 surrounded by the liquid crystal display element 1, the incident side transparent member 4 and the holding frame 52.

Part of the heat generated in the liquid crystal display element 1 is transferred to the peripheral part by contact heat conduction, and the remaining part is transferred by exchanging heat with the gas inside the closed space 2. In the heat conduction by the contact, the heat is transmitted to the holding frame 52 and transmitted to the outside of the liquid crystal display unit 15. The heat exchanged with the gas generates natural convection,
The heat is exchanged again with the holding frame 52 and transmitted to the holding frame 52. On the other hand, the emission surface side of the display pixel area 1a is in contact with the outside air, and is radiated by the cooling air convection generated by the cooling fan 26. There is a possibility that dust adheres to the emission surface side of the display pixel area 1a. However, by setting the focal point position of the projection optical system on the incident surface side of the liquid crystal display element 1, a dust shadow is not generated on an image. Absent. Of course, the closed space 2 is provided on the incident surface side, so that dust does not adhere.

In the second embodiment, since heat can be radiated to a place distant from the liquid crystal display unit 15 through the heat pipe, the degree of freedom for the heat radiating means is increased.
There is an effect that the cooling capacity for the liquid crystal display unit 15 can be improved.

In the second embodiment, the closed space in contact with the display pixel area 1a is provided on the incident surface side. However, the closed space is provided on the output surface side so that the focal point of the projection optical system can be displayed on a liquid crystal display. The element may be provided on the emission surface side of the element 1. Further, it may be provided on both sides of the entrance / exit surface.

FIG. 8 is a sectional view showing an example of the configuration of each part of the liquid crystal display unit according to the third embodiment of the present invention.

1 is a liquid crystal display element, 4 is an incident side transparent member,
2 is a sealed space surrounded by the liquid crystal display element 1, the incident side transparent member and the holding frame 52, 52 is a holding frame of the liquid crystal display element 1, 60 is a heat transfer element, 61 is a radiation fin, and 15 is a liquid crystal display element 1 , A closed space 2, an incident side transparent member 4, and a holding frame 52. Reference numeral 26 denotes a cooling fan that generates air convection for cooling. Numeral 90 indicates a light incident direction. As the heat transfer element 60, for example, a Peltier element is used.

The third embodiment of the present invention is different from the first and second embodiments in that the heat transfer element 60 is fixedly in contact with the holding frame 52 and is electrically controlled by means not shown. The heat transfer element 60 performs the operation of absorbing heat from the contact surface side of the holding frame 52 and releasing heat from the opposite side. The heat dissipating fins 61 are fixedly contacted to the heat dissipating surface side of the heat transfer element 60.

A part of the heat generated in the liquid crystal display element 1 is transferred to the peripheral part by contact heat conduction, and the remaining part is transferred by exchanging heat with the gas inside the closed space 2. In the heat conduction by the contact, the heat is transmitted to the holding frame 52 and transmitted to the outside of the liquid crystal display unit 15. The heat exchanged with the gas generates natural convection,
The heat is exchanged again with the holding frame 52 and transmitted to the holding frame 52. Part of the heat of the holding frame 52 is transmitted to other structural members that come into contact, and part of the heat is transmitted to the radiating fins 61 via the heat transfer element 60 and radiated.

In FIG. 8, the radiating fins 61 are shown as being orthogonal to the convection direction of the cooling air for the sake of explanation, but the actual radiating fins are arranged in parallel (at right angles to the drawing) in the convection direction of the cooling air. .

According to the present embodiment, since the holding frame 52 receives heat from the contact surface of the heat transfer element 60, a larger amount of heat is directly transferred to the cooling air convection than the heat transfer element 6 does.
Since it is transmitted to 0, there is an effect that the cooling capacity for the liquid crystal display unit 15 can be improved.

FIG. 9 is a sectional view showing an example of the configuration of each part of the liquid crystal display unit according to the fourth embodiment of the present invention.

1 is a liquid crystal display element, 4 is an incident side transparent member,
Reference numeral 5 denotes an emission-side transparent member, reference numeral 2 denotes an enclosed space surrounded by the liquid crystal display element 1 and the input-side transparent member 4, a holding frame 6 and a transparent member holding frame 71, 6 denotes a holding frame of the liquid crystal display element 1, and 71 denotes an incident side. The transparent member holding frame 15 for arranging and fixing the transparent member 4 to the holding frame 6 is a liquid crystal display unit having these configurations. Numeral 90 indicates a light incident direction.

In the description of FIGS. 9 to 11, the cooling fan for causing the convection of the cooling air outside the liquid crystal display section is omitted because it is the same as the above-described embodiment.

The fourth embodiment is different from the first to third embodiments in that the incident side transparent member 4 is arranged and fixed to the holding frame 6 by the transparent member holding frame 71 with a gap therebetween. In addition, the transparent member holding frame 71 radiates heat from the closed space 2 to the outside and functions as a cooling mechanism. The transparent member holding frame 71 is made of, for example, Fe, Cu, A
It is formed of a metal such as l or Mg and a material containing them. The transparent member holding frame 71 is formed, for example, by drawing with a press. The transparent member holding frame 71 is provided with an opening that is substantially smaller than the incident side transparent member 4 to be held by one turn, and does not hinder the optical path to the display pixel area of the liquid crystal display element 1.

According to this embodiment, there is no need to provide a structure for maintaining the gap between the incident side transparent member 4 and the liquid crystal display element 1 in the holding frame 6, and the structure of the holding frame 6 is simplified. .

FIG. 10 is a sectional view showing an example of the configuration of each part of the liquid crystal display unit according to the fifth embodiment of the present invention.

1 is a liquid crystal display element, 4 is an incident side transparent member,
Reference numeral 5 denotes an emission-side transparent member, 2 denotes an enclosed space surrounded by the transparent members 4 and 5, a holding frame 6 and a transparent member holding frame 71, 6 denotes a holding frame of the liquid crystal display element 1, and 71 denotes an incident-side transparent member 4. A transparent member holding frame 73 arranged and fixed to the frame 6, 73 is a structural member for floating the liquid crystal display element 1 from the holding frame 6, and 15 is a liquid crystal display section having these configurations. Numeral 90 indicates a light incident direction.

This embodiment is different from the first to fourth embodiments in that the structural member 73 makes the liquid crystal display element 1
Has a structure in which a gap is formed with respect to the holding frame 6 at least in part, so that a gas in contact with the input / output surface of the liquid crystal display element 1 can be convected. The structural member 73 may be provided on the surface of the holding frame 6 or the liquid crystal display element 1.

According to this embodiment, the liquid crystal display element can be cooled effectively by the convection of the gas in contact with both the input and output surfaces of the liquid crystal display element.

FIG. 11 is a sectional view showing an example of the configuration of each part of the liquid crystal display unit according to the sixth embodiment of the present invention.

1 is a liquid crystal display element, 4 is an incident side transparent member,
5 is an emission side transparent member, 2 is an enclosed space surrounded by the transparent members 4 and 5, the holding frame 6, and the transparent member holding frames 71 and 72,
6 is a holding frame of the liquid crystal display element 1, 71 and 72 are transparent member holding frames for disposing and fixing the transparent members 4 and 5 with respect to the holding frame 6,
Reference numeral 15 denotes a liquid crystal display unit having these configurations. Also, 9
0 indicates the incident direction of light.

This embodiment is different from the first to fifth embodiments in that the holding frame 6 is provided with an opening for venting the sealing gas, and the entrance side sealing space and the exit side sealing space of the holding frame 6 are provided. The point is that the space is connected and convection is possible.

According to this embodiment, the gas in contact with both the input and output surfaces of the liquid crystal display element is convected, so that the liquid crystal display element can be effectively cooled and the structure can be simplified. I can do it.

In FIG. 11, the transparent members 4, 5 are arranged on the holding frame 6 side with respect to the transparent member holding frames 71, 72. Thereby, the outside air contact area of the transparent member holding frames 71 and 72 increases.

Since the transparent glass and the translucent organic resin used for the transparent member have a very low heat transfer coefficient as compared with the transparent member holding frame made of metal or the like, the transparent member emits more heat than the transparent member holding frame. The contribution is small. Therefore, by increasing the outside air contact area of the transparent member holding frames 71 and 72, the effect of improving the cooling capacity can be obtained.

In the above-described embodiment, the description has been made of the case where the polarization type liquid crystal panel system is used as the liquid crystal display means. However, other types of liquid crystal display devices, for example, the scattering type liquid crystal panel system and the micro mirror (micro mirror) It goes without saying that the same effect can be obtained even in the case of the (driving) method or the laser liquid crystal writing method. Also, the optical system has been described using a refractive lens. However, even if an optical element other than the refractive lens, for example, a reflective mirror lens is used, or a combination of a refractive lens and a reflective mirror lens is used. It goes without saying that a similar effect can be obtained.

[0054]

As described above, in the liquid crystal display device of the present invention, the entrance / exit surface side of the liquid crystal display element is placed in a closed space, and further connected to the remaining wall cooling means in the closed space. The generated heat can be efficiently cooled, and further, there is an effect that dust can be prevented from entering from outside the enclosed space.

Further, since the sealed space can be made small,
It also has the effect that the device can be made smaller and more compact.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration example of each part of a liquid crystal display unit according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing an internal configuration of the first embodiment of the present invention.

FIG. 3 is a perspective view showing an appearance of a closed space according to the first embodiment of the present invention.

FIG. 4 is a schematic diagram showing the entire optical system of the liquid crystal projector according to the embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a configuration example of each part of a liquid crystal display unit according to a second embodiment of the present invention.

FIG. 6 is a perspective view showing an internal configuration of a second embodiment of the present invention.

FIG. 7 is a perspective view showing the appearance of a closed space according to a second embodiment of the present invention.

FIG. 8 is a cross-sectional view illustrating a configuration example of each part of a liquid crystal display unit according to a third embodiment of the present invention.

FIG. 9 is a cross-sectional view illustrating a configuration example of each part of a liquid crystal display unit according to a fourth embodiment of the present invention.

FIG. 10 is a cross-sectional view illustrating a configuration example of each part of a liquid crystal display unit according to a fifth embodiment of the present invention.

FIG. 11 is a cross-sectional view illustrating a configuration example of each part of a liquid crystal display unit according to a sixth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display element, 1a ... Display pixel area 4 of the liquid crystal display element 1, 5 ... Transparent member, 2, 3 ... Sealed space, 6 and 52 ... Holding frame, 7 ... Panel plate, 15, 15R, 15G, 1
5B: liquid crystal display unit, 26: cooling fan, 90: incident direction of light, 30: light source, 31: reflecting mirror, 32, 33: multi-lens, 34 to 39: separating optical system, 40R, 40G, 4
0B: condenser lens, 41R, 41G, 41B: incident side polarizer, 42: synthetic optical system, 43: projection lens, 4
4 ... Screen, 50 ... Heat pipe, 51, 61 ... Heat radiating fin, 60 ... Heat transfer element, 71,72 ... Transparent member holding frame, 73 ... Structural member for floating the liquid crystal display element from the holding frame.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toru Numata 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Within the Multimedia Systems Development Headquarters, Hitachi, Ltd. (72) Inventor Hisao Inage Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa No. 292 Co., Ltd. Visual Information Media Division, Hitachi, Ltd.

Claims (9)

[Claims] 1. A liquid crystal display comprising a light source, liquid crystal display means for modulating light from the light source, projection means for projecting light modulated from the liquid crystal display means, and a cooling fan for cooling the liquid crystal display means. In the device, a light transmissive cover member made of a glass plate is provided on a light incident side and / or a light exit side of the liquid crystal display means, and the cover member has a substantially rectangular opening with respect to the liquid crystal display means. A liquid crystal display device characterized in that the internal air is hermetically held in a substantially airtight state via a liquid crystal display, and the holding member has a cooling means. 2. The liquid crystal display device according to claim 1, wherein said cooling means is a heat pipe, wherein a cooling portion of said heat pipe is arranged on said holding member, and a heat radiating portion of said heat pipe is held by said holding member. A liquid crystal display device, wherein the liquid crystal display device is arranged in a direction opposite to a gravity direction of a member. 3. The liquid crystal display device according to claim 2, wherein the heat radiating portion of the heat pipe is a radiation fin. 4. The liquid crystal display device according to claim 2, wherein the heat radiating portion of the heat pipe is a heat transfer element and a heat radiating fin. 5. The liquid crystal display device according to claim 2, wherein the heat radiating portion of said heat pipe is fixedly contacted with another low temperature portion. 6. The liquid crystal display device according to claim 1, wherein said cooling means is a heat transfer element and a heat radiating part, wherein a cooling part of said heat transfer element is arranged on said holding member. apparatus. 7. The liquid crystal display device according to claim 1, wherein said cooling means is a radiation fin. 8. A liquid crystal display device according to claim 1, wherein said liquid crystal display means is fixed to said liquid crystal display device by fixing means, and said fixing means is fixed via a holding member of said liquid crystal display means. Or a holding member of the liquid crystal display means is integrated with the fixing means. 9. The liquid crystal display device according to claim 1, wherein said cover member is provided on a light incident side and a light emitting side of said liquid crystal display means, and said substantially airtight internal air is supplied to said light incident side. A liquid crystal display device, wherein the holding member is configured to be in a communicating state in which the holding member and the light emitting side are movable with respect to each other.