JP2001125057A - Projection display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection display device with a cooler highly efficient in cooling a liquid crystal panel. SOLUTION: The device is equipped with a light source 1 the light emitted by which irradiates the liquid crystal panel 4, a prism 6 synthesizing light spatially modulated corresponding to pictures displayed on the panel 4, a projection lens 7 enlarging and projecting the pictures displayed on the panel 4 by projecting light transmitted from the prism 6 on a screen or the like and a turbulent flow source 9 improving cooling efficiency of the panel 4 by generating turbulent flows in gaps between a polarizer 3 and the panel 4 and between an analyzer 5 and the panel 4 using an air blast generated by a cooling fan 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection display device, and more particularly to a projection display device provided with a cooling device having high cooling efficiency.

[0002]

2. Description of the Related Art As an example of a projection type display device, there is a liquid crystal projector device which enlarges and projects an image displayed on a liquid crystal panel or the like onto a screen or the like by light emitted from a light source.
In the liquid crystal projector device, the image quality of an image displayed on the liquid crystal panel is deteriorated due to overheating of the liquid crystal panel due to the emitted light, and the image quality may be deteriorated even in an image enlarged and projected on a screen or the like. Further, the life of the liquid crystal panel is shortened. As a measure for solving the above-mentioned problems, a projection display device including a cooling fan for cooling a liquid crystal panel by air is known.

FIG. 3 is a schematic view showing a structure of a projection type display device having a conventional cooling fan. In the projection display device shown in FIG.
Are condensed, transmitted through the polarizer 3, spatially modulated according to the image displayed on the liquid crystal panel 4, transmitted through the analyzer 5, and irradiated on the prism 6. Then, the transmitted light from the prism 6 is projected on a screen or the like by the projection lens 7,
The image displayed on the liquid crystal panel 4 is enlarged and projected.

[0004] The overheated liquid crystal panel 4 includes a cooling fan 8.
It is cooled by the blast from. That is, gaps are provided between the polarizer 3 and the liquid crystal panel 4 and between the analyzer 5 and the liquid crystal panel 4, and the air flows on the surface of the liquid crystal panel 4 to cool the liquid crystal panel. The air flows as shown by the arrows shown in FIG.

[0005] Also, Japanese Patent Application Laid-Open No. Hei 3-13933 discloses that
There is disclosed a projection type display device capable of increasing the air flow to increase the cooling efficiency. In such a device, a configuration is used in which cooling air flows smoothly over the liquid crystal panel to prevent turbulence, thereby increasing the air flow.

[0006]

However, with the trend toward smaller, lighter and higher brightness projection type display devices, the optical components used in the devices have also been reduced in size. Due to an increase in heat density due to miniaturization of optical components, the cooling efficiency of a liquid crystal panel or the like is reduced, and a projection display device having a cooling device with higher cooling efficiency is required.

With respect to the overheating of the liquid crystal panel, in the conventional technology, the number of rotations of the motor of the cooling fan is increased to increase the air volume, or the air flows smoothly on the surface of the liquid crystal panel. The cooling efficiency was improved. However, in order to keep the temperature rise constant, it is necessary to increase the air flow by a factor of 2 with respect to the increase in the amount of heat generated. There was a limit to eliminating degradation.

Further, there is a problem that power consumption increases due to an increase in the number of rotations of the motor of the cooling fan, and noise around the apparatus increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a projection display device having a cooling device with higher cooling efficiency.

[0010]

According to a first aspect of the present invention, there is provided a projection type display device including a cooling fan for enlarging and projecting an image displayed on a liquid crystal panel by light emitted from a light source and air-cooling the liquid crystal panel. In the projection display device, a turbulence is generated from the air blown by the cooling fan, and a turbulence generating means is provided for cooling the liquid crystal panel by the turbulence.

In the projection type display device according to the second aspect of the invention, the turbulence generating means is a rod-shaped solid object.

In the projection display device according to the third aspect of the invention, the solid object is a plate.

According to a fourth aspect of the present invention, the turbulence generating means is a solid object including a projection or a depression.

In the projection display apparatus according to the invention, the turbulence generating means is a piezoelectric vibrator.

In the projection type display apparatus according to the invention, the turbulence generating means is arranged on the upstream side of the air blow.

[0016]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing one embodiment of a projection display device according to the present invention. In the projection display device shown in FIG. 1, light emitted from a light source 1 is condensed by a condenser lens 2 and is applied to a polarizer 3. The transmitted light from the polarizer 3 is spatially modulated in accordance with an image displayed on the liquid crystal panel 4 and is applied to the analyzer 5. Here, there are three types of liquid crystal panels 4 inside the device for red light emission, green light emission, and blue light emission according to the three primary colors of light. FIG. 1 shows a cross section of one of the liquid crystal panels.

The transmitted light from the analyzer 5 is applied to the prism 6. The prism 6 combines the transmitted light (red light, green light, and blue light) from the analyzer 5 and irradiates the light to the projection lens 7. The projection lens 7 projects the transmitted light from the prism 6 onto a screen or the like, and enlarges and projects an image displayed on the liquid crystal panel 4. The turbulence source 9 generates a turbulent flow from the blast generated by the cooling fan 8. The liquid crystal panel 4 is cooled by the turbulence.

Hereinafter, the operation will be described with reference to FIG. The light source 1 irradiates high-intensity emitted light to the condenser lens 2. The light source 1 is composed of, for example, a metal halide lamp. The condenser lens 2 condenses the emitted light so as to uniformly irradiate the surface of the liquid crystal panel 4 with light, and irradiates the light to the polarizer 3. The transmitted light from the polarizer 3 is spatially modulated in accordance with the image displayed on the liquid crystal panel 4 and is applied to the analyzer 5.

The liquid crystal panel has a polarization component of light (P polarization, S polarization).
(Polarized light), image information and the like are displayed using one polarized light. Generally, a liquid crystal panel uses S-polarized light to display image information. Then, assuming that the liquid crystal panel 4 shown in FIG. 1 also displays image information and the like using S-polarized light, P-polarized light among the polarized light components becomes unnecessary. In this case, the polarizer 3 and the analyzer 5 absorb P-polarized light.

The prism 6 combines the transmitted light (red light, green light, and blue light) from the analyzer 5 and irradiates the light to the projection lens 7. The projection lens 7 projects the transmitted light from the prism 6 onto a screen or the like. Then, the image displayed on the liquid crystal panel 4 is enlarged and projected on a screen or the like.

The above is the description of the operation until the image displayed on the liquid crystal panel 4 is enlarged and projected. Next, the operation of the cooling device inside the projection display device, which is a characteristic part of the present invention, will be described.

The light emitted from the light source 1 has high brightness, and the liquid crystal panel 4 is overheated by the emitted light. Due to the overheating, the contrast of the surface of the liquid crystal panel 4 varies, and the quality of an image enlarged and projected on a screen or the like may deteriorate. Further, the life of the liquid crystal panel 4 is shortened. Therefore, it is necessary to cool the liquid crystal panel 4 in order to maintain image quality and the like.

The cooling fan 8 is constituted by a centrifugal fan, and air is generated by rotation of the centrifugal fan. The air flows as shown by the arrows shown in FIG. Here, the centrifugal fan is
A fan that blows air using centrifugal force by using a large number of blades. Then, a turbulent flow (Kalman vortex) is generated between the turbulent flow source 9 provided in the upstream portion of the blast and the liquid crystal panel 4 due to separation of the blast flow at the corner of the turbulent flow source 9. Therefore, turbulence also occurs in the gap between the polarizer 3 and the liquid crystal panel 4 and in the gap between the analyzer 5 and the liquid crystal panel 4. The turbulence source 9 is a rod-shaped solid, for example, a rod-shaped solid such as a cylinder, a square, a triangle, an ellipse, and a star. The solid may be a plate.

Generally, when a turbulent flow occurs, the airflow resistance increases and the airflow from the cooling fan decreases. However, by using a centrifugal fan having a high static pressure for the cooling fan 8, it is possible to secure a sufficient air flow even if there is some ventilation resistance, and to generate turbulence from the turbulence source 9.

In the region where the turbulence is generated, the heat conductivity is higher than in the region where the turbulence is not generated even if the air flow from the cooling fan is the same. That is, the generation of the turbulent flow can improve the cooling efficiency of the liquid crystal panel 4.
In addition, since it is possible to suppress an excessive increase in the number of revolutions of the cooling fan 8, problems in the conventional technology such as an increase in power consumption and an increase in noise around the device are solved.

FIG. 2 is an explanatory view showing another embodiment of the projection display apparatus according to the present invention. The projection display device shown in FIG. 2 is obtained by changing the turbulence source 9 which is a rod-like solid object of the projection display device shown in FIG. 1 to a turbulence source 19 which is a piezoelectric vibrator.

By using a piezoelectric vibrator as the turbulence source 19 and vibrating the vibrating plate, the turbulence source 19 at the corner of the turbulence source 19 can be compared with the turbulence source 9 shown in FIG. Turbulence (Kalman vortex) is generated efficiently. Therefore, a turbulent flow is also efficiently generated in the gap between the polarizer 3 and the liquid crystal panel 4 and also in the gap between the analyzer 5 and the liquid crystal panel 4. Therefore, the cooling efficiency of the liquid crystal panel 4 is further improved. In the projection type display device shown in FIG. 2, a piezoelectric vibrator is used as the turbulent flow source 19, but the turbulent flow source 19 may be a solid object including a plate, a projection or a depression.

[0028]

According to the first aspect of the present invention, there is provided a projection display apparatus having a cooling fan for projecting an image displayed on a liquid crystal panel in an enlarged manner by light emitted from a light source and cooling the liquid crystal panel by air. Since the turbulence is generated by the blast generated by the fan and the turbulence generating means is provided to cool the liquid crystal panel by the turbulence, the cooling efficiency of the liquid crystal panel can be improved by the turbulence. This has the effect.

According to the second aspect of the present invention, since the turbulence generating means is a rod-shaped solid, the turbulence is generated by the separation of the blast flow generated by the cooling fan at the corner of the solid, and the turbulence is generated by the turbulence. There is an effect that the cooling efficiency of the liquid crystal panel can be improved.

According to the third aspect of the present invention, since the solid object is a plate, a turbulent flow is generated at the corner of the plate, and the turbulent flow can improve the cooling efficiency of the liquid crystal panel. .

According to the fourth aspect of the present invention, since the turbulence generating means is a solid material including a protrusion or a depression, a turbulence is generated on the surface of the protrusion or the depression, and the turbulence causes the liquid crystal panel. There is an effect that the cooling efficiency can be improved.

According to the fifth aspect of the present invention, since the turbulence generating means is a piezoelectric vibrator, turbulence is efficiently generated by the diaphragm of the piezoelectric vibrator, and the turbulence reduces the cooling efficiency of the liquid crystal panel. There is an effect that it can be further improved.

According to the sixth aspect of the present invention, the turbulence generating means is arranged upstream of the air flow, so that turbulence is generated on the surface of the liquid crystal panel and the cooling efficiency of the liquid crystal panel is improved. This has the effect that it can be performed.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing one embodiment of a projection display device according to the present invention.

FIG. 2 is an explanatory diagram showing another embodiment of the projection display device according to the present invention.

FIG. 3 is an explanatory view schematically showing a conventional projection display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light source 2 Condensing lens 3 Polarizer 4 Liquid crystal panel 5 Analyzer 6 Prism 7 Projection lens 8 Cooling fan 9 Turbulence source

Continuation of the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (reference) H04N 5/64 541 H04N 5/64 541J 5/74 5/74 K 9/31 9/31 DF term (reference) 2H088 EA15 EA68 HA18 HA23 HA24 HA28 MA20 5C058 AA06 AB03 BA30 EA01 EA02 EA12 EA26 EA43 5C060 BA04 BA07 BB13 BC05 DB09 GA02 HC05 HC09 JA29 JB06 5G435 AA00 AA18 BB12 BB15 BB17 DD02 DD04 05

Claims (6)

[Claims] 1. A projection display device having a cooling fan for enlarging and projecting an image displayed on a liquid crystal panel by light emitted from a light source and cooling the liquid crystal panel by air, wherein a turbulent flow is generated from air blown by the cooling fan. A projection type display device comprising turbulence generating means for generating and cooling a liquid crystal panel by the turbulence. 2. The projection type display device according to claim 1, wherein the turbulence generating means is a rod-shaped solid object. 3. The projection display device according to claim 2, wherein the solid object is a plate. 4. The projection display device according to claim 1, wherein the turbulence generating means is a solid object including a protrusion or a depression. 5. The projection display according to claim 1, wherein the turbulence generating means is a piezoelectric vibrator. 6. The projection type display device according to claim 1, wherein the turbulence generating means is installed on an upstream side of the blower.