JPH01158480A - Display - Google Patents

Abstract

PURPOSE: To suppress a rise in temperature and obtain high luminous flux with small-sized, low-electric-power constitution by fitting a 1st polarizing plate on the side of a light guide between two polarizing plates, arranged in front of and behind a liquid crystal light valve for an image display, to the light guide. CONSTITUTION: The light emitted by a light source 1 is split in the light guide 2 into lights of red, green, and blue as the primary colors, which are guided and polarized by 1st polarizing plates 3R, 3G, and 3B. Further, they are fitted to glass plates 4R, 4G, and 4B for secure fixation and prevention against the thermal deformation of the polarizing plates, and fixed by being fitted to the light guide 2. Therefore, when a cooling fan 12 is used as a blow-out type, the 1st polarizing plate 3B is cooled with the linear wind of the cooling fan to prevent the air from flowing in the light guide 2, and the liquid crystal light valve 5B is sufficiently cooled. Consequently, temperature rises of the 1st polarizing plates 3R, 3G, and 3B and liquid crystal light valves 5R, 5G, and 5B are minimized to obtain high luminous flux with the small-sized and low-electric- power constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a projection type display device that enlarges and projects an image formed by a liquid crystal light valve using a projection lens.

[Conventional technology]

Conventionally, as shown in FIG. 5, a display device has been known in which a first polarizing plate 16B on the optical waveguide 2 side is attached to a guide plate 6B used for adjusting and fixing the position of the liquid crystal light valve 5B. .

[Problem that the invention seeks to solve]

However, in the conventional display device, the first polarizing plate 16B is attached to the guide plate 6B and blocks the window at the center of the guide plate 6B. The liquid crystal light valve 5B and the first polarizing plate 16B will have a significant temperature rise, which will cause the liquid crystal light valve 5B and the first polarizing plate 16B to increase significantly. The image quality deteriorates because the orientation of the light pulp 5B is disturbed. Furthermore, since it is necessary to raise the guaranteed temperature of the first polarizing plate 16B, it becomes difficult to increase the degree of polarization of the polarizing plate, which also leads to deterioration of image quality. In order to prevent image quality deterioration due to the above causes, it is necessary to increase the cooling capacity with a large-capacity cooling fan, but this makes it difficult to reduce power consumption and downsize. Since there is a limit to the cooling capacity in the bag-shaped space between the liquid crystal light valve 5B and the liquid crystal light valve 5B, it is necessary to reduce the output light flux, which is a big problem for projection type display devices.

Therefore, the present invention aims to solve these problems.
The purpose is to provide a display device that can suppress the temperature rise of the liquid crystal light valve and the first polarizing plate, and achieve high luminous flux with a small size and low power consumption without deteriorating image quality. .

[Means for solving problems]

In order to solve the above problems, the display device of the present invention is a display device in which light emitted from a light source is guided by an optical waveguide, an image is formed by a liquid crystal light valve, and the image is enlarged and projected by a projection lens. Of the two polarizing plates that sandwich the liquid crystal light valve in front and behind each other for image display, the first polarizing plate on the optical waveguide side is attached to the optical waveguide.

[Effect]

When air is blown onto the image forming unit consisting of the liquid crystal light valve and the polarizing plate configured as described above, for example from below using a cooling fan, the air smoothes the surfaces of the first polarizing plate and the liquid crystal light valve. Since the liquid flows through the upper part of the image forming unit, the first polarizing plate and the liquid crystal light valve can be efficiently cooled, and a display device with a small size, low power consumption, and high luminous flux can be realized with high image quality.

〔Example〕

Embodiments of the present invention will be described below based on the drawings. 1st
The figure is a plan view showing a basic configuration diagram representing one embodiment of the present invention. The light emitted from the light source 1 passes through the optical waveguide 2
The light is separated into three primary colors of red, green, and blue, and is then polarized by the first polarizing plates SR, 5Ck, and 3B. The first polarizing plates 5R, 5G, and 3B are respectively attached to glass plates 4R, 4G, and 4B, which are coated with anti-reflection coatings on both sides, in order to securely fix the plates and prevent thermal deformation of the polarizing plates. , 4G, and 4B to the optical waveguide 2. First polarizing plate 3R,, 5Ck,
The light polarized by 3B passes through the liquid crystal light valve 5R.
, 5G, and 5B, and receive polarized light from the second polarizing plates 7R, 7G, and 7B, and then are synthesized by the prism 8. The liquid crystal light valves SR, 5G, and 5B are provided with a guide plate 6R having a window in the center for reliable fixing and position adjustment.

6G and 48, respectively, and held in a position relative to the prism 8. The lights combined by the prism 8 are enlarged and projected by the projection lens 9, and an image is projected onto the screen in front.

FIG. 2 is a sectional view of the basic configuration diagram shown in FIG. 1 viewed from the projection lens 9 side, and is a detailed enlarged view of FIG. 1. Prism 8 is attached to prism fixing plates 10 and 11 from above and below.
A spacer 13 is fixed on the top of the cooling fan 12.
Mounted via. The liquid crystal light valve 5B is fixed to the guide plate 6B by a plate 14B, and is held in a position relative to the prism 8 by attaching the guide plate 6B to the prism fixing plate 10.11. In FIG. 2, when the cooling fan 12 is used as a blower, wind is generated as shown by the arrow in FIG.
The first polarizing plate 3B is cooled by the linear wind of the cooling fan and prevents air from flowing into the optical waveguide 2, and the liquid crystal light valve 5B prevents air from flowing into the optical waveguide 2 from the lower part of the prism fixing plate 11. It is sufficiently cooled by the wind blowing in through the window provided in the door plate 6B. At this time, by providing the air guide plate 15B above the cooling fan 12, the cooling capacity can be further improved. Although FIG. 2 only shows the area around the blue liquid crystal light valve 5B, the same applies to the area around the other liquid crystal light valves SR and 5G. Further, the cooling fan 12 can provide the same cooling effect even if it is provided not only at the bottom but also at the top or in an oblique direction.

〔Effect of the invention〕

As explained above, according to the present invention, by attaching the first polarizing plate, which was conventionally attached to the guide plate, to the optical waveguide, the flow of air from the window in the center of the guide plate becomes active, and the light guide It also prevents air from flowing into the wave tube, maximizing the cooling capacity of the cooling fan and
The temperature rise of the polarizing plate and liquid crystal light valve can be suppressed to a minimum. Therefore, it is possible to realize a display device with high luminous flux and high image quality while maintaining the conventional compact size and low power consumption using the conventional cooling fan and polarizing plate.

[Brief explanation of the drawing]

FIG. 1 is a basic configuration diagram showing one embodiment of the present invention, and FIG.
The figure is a detailed cross-sectional view of the embodiment shown in Figure 1, and Figure 3 is a
1 is a detailed cross-sectional view representing the prior art; FIG. 1... Light source 2... Optical waveguide 3R, 3G, 3B... First polarizing plate 4R, 4G
, 4B...Glass plate SR, 5G, 5B...
...Liquid crystal light valves 6R, 6G, 6B...Guide plates 7R, 7G, 7B...Second polarizing plate 8
・・・・・・Prism 9
・・・・・・Projection lens 10.11 ・・・・・・
・Prism fixing plate 12...Cooling fan 13...Spacer 14B
......LCD light valve mounting plate 15B
...Blast guide plate 16B...
...Conventional applicant for the first polarizing plate and above Representative of Seiko Epson Co., Ltd. Patent attorney Mogami (1 other person) Figure 1

Claims (1)

[Claims] In a display device in which light emitted from a light source is guided through an optical waveguide, an image is formed by a liquid crystal light valve, and the image is enlarged and projected by a projection lens, two sheets sandwiching the liquid crystal light valve in front and behind each other for image display. A display device characterized in that, among the polarizing plates, a first polarizing plate on the optical waveguide side is attached to the optical waveguide.