JPH06265855A - Projection type display device and display panel unit for the same - Google Patents

Abstract

PURPOSE:To prevent color unevenness and deterioration in uniform picture quality due to variance in contrast between the peripheral part and center part of a display panel. CONSTITUTION:A semicylindrical projection part 24 is provided in the display panel unit equipped with a display panel 22 to make the flow speed of cooling air fast at the center part, and fins 27 for air flow rate adjustment is arranged in the cooling air intake 25 or outlet 26 of the display panel to increase the air flow rate larger at the center part of the display panel than at the peripheral part. Consequently, the temperature difference between the peripheral part and center part of the display panel 22 is reduced to eliminate variance in contrast.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type display device for enlarging and projecting a display image of a display panel on a screen surface and a display panel unit therefor.

[0002]

2. Description of the Related Art Recently, as a display device for displaying an image using a display panel such as a liquid crystal display panel, a projection type display device for displaying a display image of the display panel on a screen surface has been considered. In this projection display device, a light source is arranged behind a transmissive display panel to illuminate from the back side of the display panel, and the light passing through the display panel, that is, the display image of the display panel is provided in front of the display panel. Since the image is magnified and projected on the screen surface by the lens, the display image can be greatly magnified and viewed even if the screen of the display panel is small.

Conventionally, in this type of projection display device, the display panel is heated by the radiation heat from the light source or the heat of the incident light to the display panel to lower the display contrast and the life of the liquid crystal. In order to prevent thermal influence, air is flown through the gap in the display panel unit to cool the display panel, thereby suppressing the temperature rise of the display panel.

[0004]

In this conventional projection display device, air is simply passed through the gap in the display panel unit to cool the display panel. However, since the light flux emitted from the light source to the display panel is larger in the central part than in the peripheral part, the temperature rise of the display panel is also higher in the central part than in the peripheral part. For this reason, there is a problem in that the contrast varies between the peripheral portion and the central portion of the display panel, and the image quality is deteriorated due to color unevenness.

The object of the present invention is to increase the temperature of the display panel in the central portion with respect to the peripheral portion due to the light flux emitted from the light source to the display panel, so that the contrast varies between the peripheral portion and the central portion of the display panel. , To prevent deterioration such as color unevenness.

[0006]

Therefore, in the projection type display apparatus of the present invention, the wind speed of the cooling air is increased in the central portion by providing the semi-cylindrical convex portion in the display panel unit having the display panel. In addition, the cooling air inflow hole or the outflow hole of the display panel unit is provided with an air volume adjusting fin, and the air volume in the central portion is increased with respect to the peripheral portion of the display panel, so that the peripheral and central portions of the display panel are It is possible to reduce the temperature difference and prevent the contrast from varying, and the above-mentioned object can be achieved.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 5 shows a schematic configuration diagram of a simple projection type display device of RGB photosynthesis method using a dichroic mirror. Figure 5
In the projection display device 1, the projection lens 3 is provided on the front surface of the housing 2, and the projection lens 3 is used by the projection lens 3.
A display image is enlarged and projected and displayed on an external screen surface (not shown) arranged in front of. Illumination light from the light source 4 is collimated by a mirror 5 and separated by dichroic mirrors 8 and 9. The separated lights are incident on the display panels built in the respective display panel units 12, 13 and 14 via the condenser lenses 15, 16 and 17, respectively. The display image formed by each display panel is color-synthesized through the dichroic mirrors 10 and 11 and the mirror 7, enters the projection lens 3, and the projection lens 3 enlarges and displays the display image.

Display panel unit 12, 1 according to the present invention
3 and 14 will be described. FIG. 1 is a cutaway perspective view of these units, and FIG. 2 is a sectional view taken along the line AA of FIG. 1. In FIGS. 1 and 2, the display panel unit has an incident side polarization plate 20 on a light flux incidence side of a shield case 19. The output side polarizing plate 21 is on the side where the light flux is emitted, the display panel 22 is inside the output side polarizing plate 21, and the display panel 22 and the incident side polarizing plate 20.
And a semi-cylindrical convex portion 24 according to the present invention. The display panel 22 is connected to a printed circuit board 23 arranged around the display panel 22.

In the gap between the display panel 22 and the semi-cylindrical projection 24 according to the present invention, cooling air is introduced into the air inflow hole 25.
And flows out from the air outlet hole 26 to cool the display panel 22. The wind speed of the air that cools the display panel 22 is increased at the central portion where the gap portion is narrowed by the semi-cylindrical convex portion 24.

Next, another example of the display panel unit according to the present invention is shown in FIGS. In the figure, the air inflow holes 25 of the unit are provided with coarse airflow adjusting fins 27 in the central portion and dense airflow adjusting fins 27 in the peripheral portion. The fins for adjusting the air flow allow the air flow of the cooling air in the direction perpendicular to the flow of the cooling air to be large in the central portion and small in the peripheral portion on the display panel 22. Further, this fin may be provided on the air outflow hole 26 side.

In the above embodiment, the RGB photosynthesis type projection type device using the dichroic mirror has been described, but the present invention arranges the light source behind the display panel and displays the display image of the display panel on this display panel. The present invention can be widely applied to a projection type display device that enlarges and projects on a screen surface by a projection lens provided in front.

[0012]

As described above, in the projection type display apparatus according to the present invention, the wind speed of the air for cooling the display panel is narrowed by providing the semi-cylindrical projections in the display panel unit. The cooling air inflow hole is provided with fins for adjusting the air flow rate, so that the cooling air flow rate is increased in the central part. This can accelerate the cooling of the central portion of the display panel, reduce the temperature difference between the peripheral portion and the central portion, and prevent the variation in contrast from occurring.
It is possible to prevent deterioration of image quality such as color unevenness.

[Brief description of drawings]

FIG. 1 is a cut-away perspective view showing a first example of a display panel unit according to the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a cutaway perspective view showing a second example of the display panel unit according to the present invention.

FIG. 4 is a cross-sectional view taken along the line BB in FIG.

FIG. 5 is a vertical cross-sectional view showing a simplified configuration of an RGB photosynthesis type projection display device using a dichroic mirror, which is one embodiment of the projection display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Projection-type display device 2 Housing 3 Projection lens 4 Light source 5-7 Mirror 8-11 Dichroic mirror 12-14 Display panel unit 15-17 Condensing lens 18 Light source box 19 Shield case 20 Incident side polarization plate 21 Emission side polarization plate 22 Display panel 23 Printed circuit board 24 Kamaboko-shaped convex portion 25 Air inflow hole 26 Air outflow hole 27 Air volume adjusting fin 28 Flow of cooling air

Claims (3)

[Claims] 1. A projection type display device in which a light source is arranged behind a transmissive display panel, and a display image of the display panel is enlarged and projected onto a screen surface by a projection lens provided in front of the display panel. A projection-type display device, characterized in that a semi-cylindrical convex portion is provided in a display panel unit including the. 2. The projection type display device according to claim 1, wherein the cooling air inflow hole or the outflow hole of the display panel unit is provided with an air flow rate adjusting fin. 3. A case, a polarizing plate provided on both surfaces of the case, a display panel provided between the polarizing plates in the case, a hole for flowing cooling air into the case, and the case. And a means for increasing the speed of the cooling air passing through the center portion of the display panel.