JPH01265227A - Cooling device for projection display equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a projection display device and a cooling device for the projection display device.

[Prior Art] Conventional projection display devices include a projection device using a TPT panel as a light valve for image formation, as disclosed in Japanese Patent Application Laid-open No. 60-179723;
Paper rLCD published on pages 375-378 of the Society for Information Display (SID) technical paper guidelines held in May 1986.
f u l 1color video proj
There are ector J, etc.

In addition, air-cooling systems have been overwhelmingly used as cooling devices for projection display devices. Furthermore, adoption of a liquid cooling system has also been reported as a small number of examples.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technology, when attempting to realize a particularly high-brightness projection display device, it is necessary to increase the output flux of the light source, and the light emitted from the light source is When the light passes through the screen, some of it is absorbed (it turns into heat, and the organic polarizing film is decomposed by this heat, degrading the polarization properties and deteriorating the display performance of the image itself projected on the screen. Therefore, a powerful temperature control system is required for this part.

However, the air cooling method, which is one of the conventional techniques, has poor cooling efficiency and inevitably requires a large cooling section. Also, the noise generated during cooling is large. Therefore, it must be said that the air cooling system has low potential.

If a high-brightness type projection display device is to be manufactured, the light source must be powerful, and the cooling must also be high performance and efficient.

Water cooling methods include natural convection, forced circulation, one-way compressor, and latent heat of evaporation methods, but the cooling efficiency of natural convection and forced circulation depends on the temperature difference from the outside air temperature, so stable high efficiency is not possible. I can't hope. A single compressor type is difficult due to the size of the compressor and the operating noise.

Based on the above, a method that uses the latent heat of evaporation of a refrigerant can be cited as a method that can be made compact and can be expected to have high cooling efficiency. However, when the application is a projection display device, the refrigerant is required to have uniform light transmittance because it cools the polarizing plate, which is a device that transmits light. Refrigerant runs out.

Furthermore, since the holding temperature is the boiling point of the refrigerant, this is disadvantageous in terms of optical uniformity of the refrigerant.

Therefore, the present invention is intended to solve these problems, and its purpose is to cool a polarizing plate using an optically uniform coolant and then replace this coolant with another coolant using another route. By adopting a cooling cycle that exchanges heat with the outside world using the latent heat of vaporization of the latter refrigerant, the aim is to achieve uniform transmission of light through the cooling section, appropriate holding temperature, and high cooling efficiency. That is.

[Means to solve the problem]

The cooling device for a projection type display device of the present invention is a cooling device that uses a liquid refrigerant to cool a polarizing plate in a projection type display device that modulates the light intensity of light emitted from a light source with a liquid crystal light valve and enlarges and projects the light with a lens. The apparatus is characterized in that the liquid refrigerant on the optical path is further cooled by another type of liquid refrigerant forming another refrigeration cycle.

[Embodiment] FIG. 1 is a configuration diagram showing an embodiment of a three-plate valve type projection display device of the present invention.

Light R201 such as halogen, xenon, metal halide, etc.
The light emitted from the blue separation dichroic mirror 211
, blue, by the green separation dichroic mirror 212
Separated into green and red primary color light. Polarizing plate 250 for each color light
The light intensity is modulated by the blue light valve 215, the green light valve 21B, and the red light valve 217, and after passing through the second polarizing plate 220, the light is combined by the dichroic prism 230 and projected into the projection lens 231.
projected onto the screen by

A cooling layer 250 exists between the color light bulb 216 and the red light bulb 217 to perform cooling. The heat generated in the polarizing plate stage is first absorbed by water, which is a refrigerant, as heat of vaporization, and is transferred to the upper part of the sealed chamber by convection. This is a contact point with the cooling layer of Freon 113, and the heat of the water is exchanged with Freon 113. The Freon vapor generated when it reaches its boiling point is introduced into the condenser through the inlet, where it radiates heat from the surface of the heat sink and is condensed.

A fan motor is used to circulate air in order to efficiently dissipate heat in the condenser. The water condensed in the condenser is returned to the evaporator through a discharge vibrator by a circulation pump, forming a refrigeration cycle.

The heating charge is 12.6W, and the heat of vaporization of water is 539cal/g.
Therefore, the circulation amount per minute is 0. 23cc/m
The circulation pump uses an intermittent actuator using a solenoid to generate a rate of 10 in per minute or more.
It has a structure that ensures a discharge amount of 0°023cc in one cycle. The pressure during use is approximately 0.5 kg/cm2.

As a result, the heat generated at 213.215.216.217 is quickly removed by 250.

In this example, a light source with a total luminous flux of 20,000 lumens is used, and the absorbed heat amount for each of blue, red, and green is 5. 2W, 4. 8W, 2. It was 6W. The cooling cycle employs a structure in which each polarizing plate is cooled by connecting them in parallel. The pressure inside the cycle is 1.68 kg
/cm2, and the heat of vaporization of the refrigerant Freon 113 at 80°C is 31.6 kcal/g, so the refrigerant flow rate required to absorb the heat of the polarizing plate is 0.081 cc/se.
It is c.

Because the required flow rate of refrigerant is small, the circulation pump is operated intermittently and a linear type solenoid is used.
The pump is driven at a frequency of z, and the pump discharge amount is 0.081 cc. In addition, by using water to cool the polarizing plate, it can be cooled at just below the boiling point, preventing bubbles from forming and fluctuations in the liquid layer, and keeping the light transmittance in the liquid layer above 95%. [Effects of the Invention] As described above, in a projection display device in which the light intensity of light emitted from a light source is modulated by a liquid crystal light valve and then enlarged and projected using a lens, liquid is used to cool the polarizing plate and the liquid crystal light valve. Equipped with a cooling device that uses a refrigerant, and by cooling the liquid refrigerant on the optical path with another type of liquid refrigerant that forms another refrigeration cycle, the light transmittance is increased and at the same time, fluctuations in the liquid layer are prevented. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram of a single-panel projection display device and a cooling device. 201 Light source 211 Blue reflective dichroic mirror 212 Green reflective dichroic mirror 213 Polarizing plate 215 Blue light bulb 216 Green light bulb 217 Red light bulb 220 @ tip plate 230 Dichroic prism 231 Projection lens 251 Freon 113 Applicant Seiko Epson Co., Ltd. Attorney Master Masayoshi Kamiyanagi (and 1 other person)

Claims (1)

[Claims] (1) In a projection display device that modulates the light intensity of light emitted from a light source with a liquid crystal light valve and enlarges and projects the light with a lens,
Cooling of a projection type display device, characterized in that it is equipped with a cooling device that uses a liquid refrigerant for cooling a polarizing plate, and the liquid refrigerant on the optical path is further cooled with another type of liquid refrigerant forming another refrigeration cycle. Device.