JPH0827450B2 - Liquid crystal display panel cooling mechanism - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling mechanism for a liquid crystal display panel used in a display device such as a liquid crystal projector.

[0002]

2. Description of the Related Art A liquid crystal projector or the like is usually used as a display device, but a liquid crystal panel is heated by a light beam from a light source and its display contrast is lowered or its life is shortened. In order to prevent this, the liquid crystal panel is generally cooled. The conventional cooling mechanism cools the display panel by air by passing cooling air through a gap in the display panel unit. For example, as shown in Japanese Utility Model Publication No. 2-17718, a gap is provided between the liquid crystal panel and the backlight,
A configuration is disclosed in which cooling air is sent through an opening provided with an air cooling fan.

[0003]

In the conventional cooling mechanism, cooling air is simply caused to flow through the gap in the display panel unit, or between the liquid crystal panel and the backlight in Japanese Utility Model Laid-Open No. 2-17718 mentioned above. All that is necessary is to cool the inside of the display panel unit by flowing cooling air into the gap. On the other hand, the luminous flux emitted from the light source to the liquid crystal panel is larger in the central part than in the peripheral part, and the temperature of the liquid crystal panel is higher in the central part than in the peripheral part. Can't handle. For this reason, there is a problem in that there is a variation in contrast between the peripheral portion and the central portion of the liquid crystal panel, which causes deterioration of image quality such as color unevenness.

The present invention has been made in view of the above-mentioned problems, in which the temperature rise of the liquid crystal panel is made uniform over the entire panel, and the liquid crystal display panel can be cooled so as to prevent deterioration of image quality such as color unevenness due to variations in contrast. The purpose is to provide a mechanism.

[0005]

In order to achieve the above object, a flat cooling path is provided between a liquid crystal panel and an incident side polarization plate.
Is provided, and both the center and the
Place multiple fins by gradually narrowing the gap toward the side.
And the central part in the width direction of the cooling passage is the maximum air volume.
Form an air volume distribution that minimizes the air volume on both sides.
The inlet and outlet of the cooling passage from the inside to the outside.
The cooling air that flows into the cooling passage is liquefied.
The liquid crystal panel is configured so that the cooling of the central portion of the liquid crystal panel is maximized and the cooling of the front and rear portions thereof is minimized by being applied to almost the central portion of the crystal panel surface .

[0006]

In the present invention having the above-described structure, the air flow rate adjusting member provided at the inflow port maximizes the air flow rate distribution in the cooling passage in the central portion in the width direction and minimizes both side portions. Cooling of the liquid crystal panel is maximized at the center and minimized at both sides. Further , in the present invention, the cooling wind hits the center of the liquid crystal panel due to the slanted load at the inflow port, and the cooling of the liquid crystal panel is maximized at the central portion and minimized at both side portions. Further , in the present invention, the velocity of the cooling air is high and the air volume is maximized in the central portion where the gap between the fins is wide.
On the other hand, in both side portions where the fins are closely spaced, the cooling air velocity is slow to minimize the air volume.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a perspective view of a partial cross section of a display panel unit 3 using a cooling mechanism for a liquid crystal display panel according to this embodiment. The display panel unit 3 is provided with an incident side polarization plate 13 on the light flux incidence side of the shield case 12 and an emission side polarization plate 14 on the light flux emission side to form the appearance. Further, the liquid crystal panel 11 is provided in the vicinity of the inner side of the exit side polarizing plate 14, a gap is provided between the liquid crystal panel 11 and the entrance side polarizing plate 13, and both ends of this gap are an inlet 16 and an outlet 18. Cooling passage 24 is formed.

As shown in FIG. 2, the plate-like fins 1 are formed at the inlet 16 and the outlet 18 by gradually narrowing the gap so that the gap is maximum in the central portion and the gap is minimum in both side portions.
A plurality of 7, 19 are provided. As a result, when the cooling air flows in the cooling passage 24, the velocity distribution (air volume distribution) in the cooling passage 24 becomes maximum at the center and minimum at both sides, as indicated by the velocity vector 20 of the arrow in FIG. .

The inlet 16 and the outlet 18 are
As shown in FIG. 3, the cooling passage 24 descends from the inside to the outside.
The slopes 16a and 18a are formed. This allows cooling
Cooling air 21 supplied to the road 24 hits the central portion of the liquid crystal panel 11, the maximum cooling of the central portion of the liquid crystal panel 11, it to the cooling of the front and rear portions of the wind direction of the cooling air 21 is minimum
It Reference numeral 15 in the drawing denotes a printed circuit board, which is arranged around the liquid crystal panel 11 and is connected by a sheet-shaped flexible connector (not shown).

Next, the operation of the cooling mechanism for the liquid crystal display panel described above will be described using the liquid crystal projector 1 having the display panel unit 3. FIG. 4 is a cross-sectional configuration diagram of the liquid crystal projector 1, which includes a projection lens 10 that projects and displays an image on the front surface of the housing 2. The light flux emitted from the light source 4 is collimated by the reflection mirror 5, passes through the reflection mirror 6, the dichroic mirror 7, and the condenser lens 8 and is applied to the liquid crystal panel 11 incorporated in the display panel unit 3. The image formed by the liquid crystal panel 11 passes through the reflection mirror 6 and the dichroic mirror 9 and then the projection lens 1
It is incident on 0 and an image is projected and displayed.

The temperature of the central portion of the liquid crystal panel 11 irradiated with the luminous flux rises more than that of the peripheral portion. However, the temperature distribution in the width direction of the liquid crystal panel 11 is as shown in FIG. 5, because the velocity in the central portion is the maximum as in the velocity distribution (air flow distribution) of the velocity vector 20 indicated by the arrow in FIG. The temperature curve 23a is flatter than that of the conventional temperature curve 22a. Further, the cooling air 21 in FIG. 3 hits the central portion of the liquid crystal panel 11, maximizing the cooling of the central portion of the liquid crystal panel 11 and minimizing the cooling in the front-back direction. As a result, as shown in FIG. 6, the temperature curve 23b becomes flat as compared with the conventional temperature curve 22b in the flow direction of the liquid crystal panel 11.

As described above, since the temperature distribution of the liquid crystal panel 11 is made uniform over the entire panel, there is no variation in contrast due to the temperature difference. As a result, it is possible to prevent deterioration of image quality such as color unevenness.

In the above-described embodiment, the fins 1 as air flow rate adjusting members are provided at both the inflow port 16 and the outflow port 18.
Although 7 and 19 are provided, the above-described operation is possible even if only the inflow port 16 is set. In addition, the inflow port 16 and the outflow port 1
The inclinations 16a and 18a provided on both sides of No. 8 are the same even if only the inflow port 16 is set.

[0014]

As described above, according to the present invention, the air flow rate adjusting member and the inclination are provided at least at the inlet to maximize the cooling of the central portion of the liquid crystal panel. Therefore, it is possible to prevent the deterioration of image quality such as color unevenness due to the variation of contrast.

[Brief description of drawings]

FIG. 1 is a perspective view of a partial cross section of a display panel unit.

FIG. 2 is a plan sectional view of a display panel unit.

FIG. 3 is a side sectional view of a display panel unit.

FIG. 4 is a cross-sectional configuration diagram of a liquid crystal projector using a display panel unit.

FIG. 5 is a temperature curve diagram showing a temperature distribution in the width direction of the liquid crystal panel.

FIG. 6 is a temperature curve diagram showing the temperature distribution in the flow direction of the liquid crystal panel.

[Explanation of symbols]

 3 Display Panel Unit 11 Liquid Crystal Panel 16 Inlet 18 Outlet 16a, 18a Inclination 17, 19 Fin 20 Speed Vector 21 Cooling Air 24 Cooling Path

Claims (1)

[Claims] 1. A flat plate between the liquid crystal panel and the incident side polarizing plate.
-Like cooling passages are provided, and the inlet and outlet of this cooling passage are directed from the center to both sides.
The fins are arranged by gradually narrowing the gap and
The central part in the width direction of the bypass is the maximum air volume and both sides are
Allowed form the air volume distribution that minimizes air volume, further outside the inlet and outlet of the cooling passage from the inside
Cooling air flowing into the cooling path
A cooling mechanism for a liquid crystal display panel, which is characterized in that the cooling of the central part of the liquid crystal panel is maximized and the cooling of the front and rear parts is minimized by applying the above to the substantially central part of the liquid crystal panel surface .