JPH0658474B2 - Liquid crystal display - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a liquid crystal television and a liquid crystal projector that illuminate a backlight from the rear surface of a transmissive liquid crystal display panel and display an image by the light transmitted through a liquid crystal layer. The present invention relates to a liquid crystal display device such as a device.

[Prior Art and its Problems] In a conventional liquid crystal display device in which light from a backlight is transmitted through a transmissive liquid crystal display panel to display an image, in order to improve the contrast of an image, a backlight of high brightness and high light amount is used. When a light is used, the liquid crystal material of the liquid crystal layer is heated by the heat generated by the light source for the backlight and the infrared rays contained in the light from the light source, and the temperature rise deteriorates the liquid crystal material, resulting in uneven brightness and contrast in the image display. However, there is a problem that a high quality image display cannot be obtained.

[Object of the Invention] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a backlight for a liquid crystal display device that illuminates a transmissive liquid crystal display panel with light from a backlight. The liquid crystal material of the liquid crystal display panel is constructed by closely adhering the cooling section filled with the cooling liquid and provided with the heat dissipation means to the liquid crystal display panel which is heated by the heat generation of the light source for light or infrared rays contained in the light from the light source. The present invention intends to provide a liquid crystal display device capable of stably obtaining a high quality image by cooling the liquid crystal display device.

[Points of the Invention] In order to achieve the above-mentioned object, the present invention encloses a cooling liquid in a container having transparent parts formed on both surfaces and releases the heat absorbed by the cooling liquid in the container to the outside of the container. The essential point is that a cooling device provided with a heat dissipation means is provided, and the liquid crystal display panel and the transparent portion on one surface of the cooling device are in close contact with each other to cool the liquid crystal display panel. .

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings.

1 and 2 are a plan view and a side view of a color liquid crystal projector device 3 in which the liquid crystal display device 1 of the present invention is set in the image projection section 2 of each optical system.

In this color liquid crystal projector device 3, three optical system projection devices 4R, 4G, and 4B that form a color image are placed in a horizontal position.
The liquid crystal image projected from is displayed on the screen 5 surface. The projection device 4R projects a red image, the projection device 4G projects a green image, and the projection device 4B projects a blue image. The color projection from the projection devices 4R, 4G, and 4B is performed by the color classification of the light source lamp 6 provided for each of the projection devices 4R, 4G, and 4B. You may go.

The images of the three primary colors projected from the projection devices 4R, 4G, and 4B are formed on the screen 5 surface, and the image composed of the liquid crystal pixels of each liquid crystal display device 1 is projected on the screen 5 surface to display a color image.

FIG. 3 shows the image projection unit 2 of the liquid crystal projector device 3.
FIG. 3 is an enlarged front view of the liquid crystal display device 1 set in each of the above. In FIG. 3, the right half of the liquid crystal display panel 7 arranged in the front is removed, and the liquid crystal display panel 7 is arranged in the rear surface. The drawing shows the internal structure of the cooling unit 8. FIG. 4 is a sectional view taken along line IV-IV shown in FIG.

In the embodiment of the liquid crystal display device 1 shown in FIGS. 3 and 4, the liquid crystal display device 1 is located on the front (viewed from the screen 5 side) liquid crystal display panel 7 and on the rear surface of the liquid crystal display panel 7. The liquid crystal display panel 7 itself is integrally combined with the cooling unit 8.

As shown in FIG. 4, the liquid crystal display panel 7 is doubled by transparent glass substrates 7a and 7b, and although not shown in the figure, a liquid crystal layer is provided between the glass substrates. ing. The liquid crystal layer is sealed between the glass substrates 7a and 7b with a sealing material to form a screen size 9. Then, on the inner surfaces of the glass substrates 7a and 7b in which the liquid crystal layer is interposed, segments for forming pixels are provided in a matrix. Also,
Although not shown in the drawing, polarizing plates are added to the outer surface positions of the liquid crystal display panel 7 in such a size as to cover the screen size 9.

The cooling unit 8 includes a transparent panel 8a having a size facing the glass substrate 7b of the liquid crystal display panel 7, a cooling layer 10 formed at a constant interval between the transparent panel 8a and the glass substrate 7b, and a cooling layer 10a. Heat dissipation fin portion 11 surrounding the layer 10
The fin portion 11 is provided with a heat radiation fin 11a and heat absorption fins 11b and 11c.

The fin portion 11 includes the glass substrate 7a and the transparent panel 8 described above.
In the case of this embodiment, the heat dissipation fins 11a are provided on the upper and lower outer sides of the frame 11d, and the heat absorbing fins 11b are on the left and right sides along the inner side of the frame 11d. It is provided. The end portions of the endothermic fins 11b are double T-shaped in cross section, and the contact surface area with the cooling liquid 12, which is filled in the cooling layer 10 and has a light diffusing property described later, can be increased. In addition, it also serves to guide a part of the convection after cooling 12.

In the above, the frame 11d has front and rear frame surfaces that are flat, and is adhered to the edges of the glass substrate 7a and the transparent panel 8a by the adhesive 13 for sealing, thereby sealing the cooling layer 10. Further, in the cooling unit 8, bulging auxiliary cooling layers 10a and 10a are integrally formed with the cooling layer 10 in the upper and lower central portions, and the upper auxiliary cooling layer 10a is heated by the cooling liquid 12 to generate convection. It is designed to collect bubbles when they occur. For this reason, the auxiliary cooling layer 10a is provided with an appropriate number of heat absorbing fins 11b for speeding up the cooling of the cooling liquid 12. The reason why the auxiliary cooling layer 10a is in the upper and lower positions is that the upper and lower sides of the liquid crystal display device 1 can be freely selected, and the auxiliary cooling layer 10a located in the lower part serves as a precipitation space for impurities.

FIG. 5 shows a natural convection state of the cooling liquid 12 in the cooling layer 10. In the use of the liquid crystal display device 1, when the light 6a of the backlight source is applied to the back surface of the liquid crystal display device 1 as shown in FIG. 4, heat or light 6 from the light source is emitted.
The central portion A of the screen size 9 of the liquid crystal display panel 7 is first heated by the infrared rays and the like contained in a.
Then, this heating causes natural convection in the cooling liquid 12, and the cooling liquid 12 in the central portion A rises to reach the upper region B.

Since the auxiliary cooling layer 10a having the endothermic fins 11c is formed in the upper region B, the cooling liquid 12 rising there is efficiently cooled by the auxiliary cooling layer 10a. Then, the cooled coolant 12 in the upper region B is
It is guided to the left and right regions by the inner wall-shaped heat absorption fins 11b provided so as not to return directly to the center of the cooling layer 10. In this case, the rise of the cooling liquid 12 in the vicinity of the central portion A where the temperature is highest reaches the central upper portion B of the auxiliary cooling layer 10a, where it is once cooled and then natural convection is used to absorb heat from the outside of the heat absorbing fins 11b. It reaches the passage c1 of the fin 11b. Then, while being cooled, it moves to the central lower portion D and returns to the central portion A of the post-cooling layer 10 to form convection and be circulated and cooled.

Further, the rise of the cooling liquid 12 in the vicinity of the peripheral portion E where the temperature rise is a little low reaches the upper portion F portion which is the step opening portion of the double endothermic fins 11b, and the convection in this portion is the endothermic fins 11b. It is cooled while reaching the passage C2 between the two while moving to the lower side portion G while being cooled, and then being circulated by convection returning to the peripheral portion E while being circulated.

Further, a part of the raised cooling liquid 12 is circulated and cooled while being cooled by the endothermic fin 11b and passing through the passage C3 between the inner endothermic fin 11b and the step of the transparent panel 8a.

On the other hand, since the cooling layer 10 has a very narrow depth, the natural convection velocity of the example liquid 12 in natural convection is improved, and efficient cooling is obtained.

FIG. 6 shows the transparent panel 8 of the cooling unit 8 shown in the above embodiment.
This is a case where the heat reflection film 14 is further coated on the a-plane. In this way, the light from the light source for the backlight 6
The heat ray 6b contained in a is reflected by the heat reflection film 14 and serves to further suppress the temperature rise of the liquid crystal material interposed in the liquid crystal layer 7c of the liquid crystal display panel 7.

Although the cooling unit 8 integrally attached to the liquid crystal display panel 7 is provided on the rear surface of the liquid crystal display panel 7 in the above embodiment, the cooling unit 8 is provided on the front surface of the liquid crystal display panel 7. Good. However, in this case, when the heat reflection film 14 is added, it is applied to the backlight side of the liquid crystal display panel 7.

The light-diffusing cooling liquid 12 filled in the cooling layer 10 is a cooling liquid (for example, an ethylene glycol aqueous solution).
And a diffusing solution (white turbid colloid solution) that is also used as a turbid solution. The diffusing liquid may be, for example, a solution in which appropriate powders are mixed as long as it can diffuse the transmitted light.

7 to 9 show another embodiment of the liquid crystal display device.

FIG. 7 shows that, like the liquid crystal display device 1 shown in the above-described embodiment, the right half of the liquid crystal display panel 16 in the liquid crystal display device 15 is removed, and the cooling unit 17 arranged on the rear surface of the liquid crystal display panel 16. The figure shows the internal structure of the.

The liquid crystal display panel 16 has the same laminated structure as the liquid crystal display panel 7 shown in the above embodiment as shown in FIG. 8, and the shape viewed from the front is such that the upper and lower portions of the left and right regions are as shown in FIG. It conforms to the shape of the cooling part 17 and extends slightly up and down.

The cooling unit 17 is integrally combined with the liquid crystal display panel 16 itself on the rear surface of the liquid crystal display panel 16 via a spacer 18. Then, in the rear image of the cooling unit 17, a light source 19 for backlight is further provided together with a reflection plate 20. The light source 19 in this embodiment is of a planar type having an appropriate number of fluorescent lamps.

In the above, the cooling part 17 is formed by the front transparent panel 17a and the rear transparent panel 17b to form the cooling layer 21, and the cooling layer 21 is closed on all four sides by frame-shaped heat radiation fins 22.

The fin portion 22 is formed by providing auxiliary cooling layers 21a at the upper and lower positions of the four corners as viewed from the front, and the heat radiating fins 22b are provided outside the frame 22a. Also,
Inside the frame 22a, there are provided an endothermic fin 22c located in the auxiliary cooling layer 21a portion and a T-shaped endothermic fin 22d provided in a position avoiding the endothermic fin 22c portion. The front and rear surfaces of the frame 22a are in close contact with the inner surfaces of the edges of the transparent panels 17a and 17b with the sealing material 23 interposed therebetween, thereby sealing the cooling layer 21. The cooling layer 21 is filled with the cooling liquid 24 having the same light diffusion property as in the above-described embodiment.

The T-shaped endothermic fins 22d also serve to guide a part of convection of the heated cooling liquid 24.

FIG. 9 is a bottom view showing a part of the liquid crystal display device 15 shown in FIG. 7 in section. As is clearer from this figure, in the cooling layer 21 of this embodiment, the transparent panel 17a,
A vertical blocking wall 25 is provided between 17b.

This blocking wall 25 has a screen size 26 as shown in FIG.
Are provided on the left and right outer sides of the cooling wall 21 so as to block the inside of the cooling layer 21, and the cooling layers 21 at the upper and lower portions of the blocking wall 25 are entirely covered by the auxiliary cooling layer 21a as shown in FIG. It is in communication.

Therefore, the liquid crystal display device 15 according to the present embodiment includes the light source 1
When the heat from 9 is applied to the cooling layer 21 side through the translucent panel 17b, the cooling liquid 24 in the cooling layer 21 absorbs the heat and causes natural convection. Due to this natural convection, the cooling liquid 24 in the central portion A where the temperature rises becomes high and reaches the upper region B.
The cooling liquid 24 reaching the upper region B is absorbed by the heat absorbing fins 22d and is radiated to the outside by the heat radiating fins 22b.

On the other hand, in the fluorescent lamp of the light source 19, since the filament portion at the end is normally heated most, the rise of the cooling liquid 24 in the side area C portion corresponding to this portion is prevented from rising upward by the blocking wall 25. The layer 21a reaches the heat absorbing portion D and is prevented from flowing into the double-sided size 26 side unintentionally. As a result, the cooling liquid 24 in the side portion C is cooled by the endothermic fins 22c of the auxiliary cooling layer 21a, and then cooled while being guided to the auxiliary cooling layer 21a below along the side T-shaped endothermic fins 22d. To be done. Then, the cooling liquid 24 cooled in the endothermic portion E of the auxiliary cooling layer 21a is cooled by performing natural convection returning to the side region C again.

On the other hand, since the cooling layer 21 is formed thin, the cooling liquid 24 in the central region A is circulated in the space between the barrier walls 25 by improving the speed of natural convection so that efficient cooling can be achieved. This can be done through the upper and lower T-shaped endothermic fins 22d.

Also in this embodiment, the heat treatment of the liquid crystal display panel 16 can be enhanced by applying the same coating treatment to the heat reflecting film 14 shown in the above embodiment on the transparent panel 17b.

[Effects of the Invention] As described in detail above, according to the present invention, in a liquid crystal display device in which a liquid crystal display panel is irradiated with light from a light source to display an image, a cooling liquid is enclosed in a container having transparent parts formed on both sides. And a cooler provided with heat dissipation means for releasing the heat absorbed by the cooling liquid in the container to the outside of the container, and one surface of the transparent part of the cooler is closely adhered to the liquid crystal display panel. By cooling the liquid crystal display panel, the liquid crystal display panel can be satisfactorily cooled without requiring a large-scale cooling means.

Therefore, according to the present invention, the temperature rise of the liquid crystal material in the liquid crystal display panel is increased in the state where heat generation of the backlight light source or heating by infrared rays contained in the light from the light source is applied to the liquid crystal display panel. It is possible to suppress the above, and it is possible to obtain an effect that uneven brightness and uneven contrast due to the temperature rise of the liquid crystal material can be prevented and a high-quality image can be stably obtained.

[Brief description of drawings]

The drawings show an embodiment of the present invention, FIG. 1 is a plan view of a color liquid crystal projector device with a part thereof shown in cross section, FIG. 2 is a side view of the same as shown with a part thereof in cross section, and FIG. 3 is a front view. FIG. 4 is a front view of a liquid crystal display device in which a part of FIG. 4 is cut away, FIG. 4 is a cross-sectional view taken along line IV-IV shown in FIG. 3, and FIG. FIG. 6 is a partial cross-sectional view of a transparent panel provided with a heat-reflecting film, and FIG. 7 is a front view of another embodiment of a liquid crystal display device in which a part of the front surface is cut away. 8 is a sectional view taken along line VIII-VIII shown in FIG. 7, and FIG.
The drawing is a bottom view showing a cross section of a part of the liquid crystal display device shown in FIG. 1 ... Liquid crystal display device, 6a ... Backlight, 7, 16
...... Liquid crystal display panel, 8, 17 ...... Cooling unit, 10, 21
... Cooling layer, 12, 24 ... Cooling liquid, 8a, 17b ...
Transparent panel, 11c, 22c ... Heat absorption fin, 11b,
22d ... T-shaped endothermic fin.

Claims (1)

[Claims] 1. A liquid crystal display device for displaying an image by irradiating a liquid crystal display panel with light from a light source, wherein a cooling liquid is enclosed in a container having transparent parts formed on both sides and the cooling liquid in the container is A cooler provided with a heat dissipation means for releasing the absorbed heat to the outside of the container is provided, and the liquid crystal display panel and the transparent portion on one surface of the cooler are closely attached to each other to cool the liquid crystal display panel. Liquid crystal display device characterized by.