JP2000269674A - Liquid crystal projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve cooling capacity by constituting a liquid crystal projector of an electronic cooling element, a cooling fin, and a radiating fin. SOLUTION: Air forcibly sucked from a suction port 6 of a sirocco fan 4 is unloaded from an exhaust vent of the fan 4, passes through the inside of a blast duct 5, and is introduced to a liquid crystal panel and its peripheral optical element. By allowing a current to flow into a Peltier element 1, heat is absorbed at a heat absorption side, and heat is generated at a heat generation side. Thus the cooling wind through the inside of the blast duct 5 when it passes a cooling fin 2 is cooled in thermally contact with the heat absorption side of the Peltier element 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal projector for enlarging and projecting an input image, and more particularly to a cooling mechanism for a liquid crystal panel.

[0002]

2. Description of the Related Art A liquid crystal projector which enlarges and projects a computer image, a video image, and the like on a screen has been known. FIG. 3 is a block diagram showing a configuration of an optical system of a conventional liquid crystal projector. The light source light emitted from the lamp 10 enters the first dichroic mirror 11. The dichroic mirror 11 transmits red light of the light from the light source and reflects other color lights. The second dichroic mirror 12 transmits blue light and reflects green light in the reflected light of the dichroic mirror 11. The red light transmitted through the dichroic mirror 11 passes through the total reflection mirror 13 and the condenser lens 16 and passes through the liquid crystal panel 1.
9, the green light reflected by the dichroic mirror 12 passes through the condenser lens 17 and enters the liquid crystal panel 20. The dichroic mirror 12
The blue light transmitted through passes through the total reflection mirrors 14 and 15 and the condenser lens 18 and enters the liquid crystal panel 21.
The dichroic prism 22 includes liquid crystal panels 19 to 21.
Are combined with each other. The light synthesized by the dichroic prism 22 is transmitted to the projection lens 23.
Is projected on a screen (not shown).

In such a liquid crystal projector, light other than the light finally projected out of the light emitted from the lamp 10 is absorbed by the liquid crystal panels 19 to 21 and the optical elements in the vicinity thereof to become heat. Therefore, the liquid crystal panels 19 to 21 and the optical elements around them are heated. Therefore,
In a conventional liquid crystal projector, cooling air taken in by an axial fan is sent to the liquid crystal panels 19 to 21 and optical elements in the vicinity thereof to be cooled. 4A, 4B, and 4C are a front view, a plan view, and a side view, respectively, of the liquid crystal projector of FIG. Also, FIG. 4D shows FIG.
It is the side view which removed the axial fan in (c). FIG.
In the figure, 24 is an axial fan, 25 is a housing of the liquid crystal projector, and 26 is an opening provided in the housing 25.

[0004]

As described above, in the conventional liquid crystal projector, the liquid crystal panel and the optical elements around it are cooled. However, in the market, there is a demand for higher brightness of the liquid crystal projector, and if the amount of light of the lamp is increased to meet such a demand, the liquid crystal panel and its surrounding optical elements will be further heated.
There is a problem that the cooling capacity is insufficient in cooling by the axial fan. SUMMARY An advantage of some aspects of the invention is to provide a liquid crystal projector that can cope with higher luminance by improving the cooling capacity as compared with the related art.

[0005]

A liquid crystal projector according to the present invention comprises a light source (10), a liquid crystal panel (19 to 21) for modulating light from the light source, and a projection optical system for projecting light modulated by the liquid crystal panel. A system (23) and a cooling mechanism for cooling the liquid crystal panel are provided. The cooling mechanism includes a blowing unit (4) that forcibly sucks air outside the housing of the liquid crystal projector, a blowing duct (5) that guides the cooling air sucked by the blowing unit to the liquid crystal panel, and heat absorbing at one end. An electronic cooling element (1) that generates heat at the other end, a cooling fin (2) disposed in the air duct and in thermal contact with the heat absorbing side of the electronic cooling element, and a thermal contact with the heat generating side of the electronic cooling element And the radiation fins (3).

[0006]

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a configuration of a cooling mechanism of a liquid crystal projector according to an embodiment of the present invention. In the present invention, the Peltier element (electronic cooling element or thermo module) 1 is used as a means for cooling the cooling air sent to the liquid crystal panels 19 to 21 and the optical elements in the vicinity thereof.

The Peltier element 1 is an element utilizing the Peltier effect that, when two different conductors (or semiconductors) are connected to each other and an electric current is applied thereto, heat is absorbed or generated at the junction. As shown in FIG. 1, a cooling fin (heat sink) 2 is thermally contacted and fixed to the heat absorbing side of the Peltier element 1, and a radiation fin (heat sink) 3 is thermally contacted to the heat generating side of the Peltier element 1. And fix it.

Further, by connecting an exhaust port of a sirocco fan (blower type fan) 4 and an intake port 6 of a blower duct 5, they are connected as shown in FIG. The ventilation duct 5 having a hollow structure is provided with an opening 7 for accommodating the cooling fins 2 and an exhaust port 8. The cooling fin 2 is fitted into the opening 7 of the air duct 5 and fixed. The cooling fins 2 are arranged in the air duct 5 so as to be parallel to the air blowing direction shown in FIG.

Thus, a cooling mechanism as shown in FIG. 2A is completed. This cooling mechanism is connected to the exhaust port 8 of the air duct 5 and the opening 2 provided in the housing 25 of the liquid crystal projector.
6 so that it is fitted to the housing 25 and fixed (FIG. 2B). The air forcibly sucked from the intake port 6 of the sirocco fan 4 is exhausted from the exhaust port of the fan 4, passes through the ventilation duct 5, and passes through the exhaust port 8 of the ventilation duct 5 and the opening 26 of the housing 25. Pass through the liquid crystal panels 19-2
1 and its surrounding optical elements.

The cooling air is exhausted from an exhaust port (not shown) provided in the housing 25 of the liquid crystal projector as shown in FIG. At this time, the Peltier element 1
When a current is passed through the heat sink, heat is absorbed on the heat absorbing side and heat is generated on the heat generating side. Thus, the cooling air passing through the air duct 5 is cooled when passing through the cooling fins 2 that are in thermal contact with the heat absorbing side of the Peltier element 1.

Therefore, since the cooling air introduced into the housing 25 is cooled to a temperature lower than the outside air temperature outside the housing 25, the temperatures of the liquid crystal panels 19 to 21 and the optical elements therearound are transmitted to the cooling mechanism. It can be lower than the conventional case using an axial fan. The heat flowing from the heat absorption side to the heat generation side of the Peltier element 1 and the heat corresponding to the power consumed inside the Peltier element 1 are radiated by radiating fins arranged outside the air duct (that is, outside the housing of the liquid crystal projector). 3 radiates heat to the outside.

[0012]

According to the present invention, the cooling mechanism is constituted by the blowing means, the blowing duct, the electronic cooling element, the cooling fins and the radiating fins, so that the cooling wind guided to the liquid crystal panel is lower than the outside air temperature outside the housing. Since the cooling is performed to the temperature, the cooling capacity can be improved as compared with the cooling mechanism using the conventional axial fan, and it is possible to cope with the high brightness of the liquid crystal projector.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a cooling mechanism of a liquid crystal projector according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a state in which the cooling mechanism of FIG. 1 is mounted on a liquid crystal projector.

FIG. 3 is a block diagram showing a configuration of an optical system of a conventional liquid crystal projector.

4 is a front view, a plan view, and a side view of the liquid crystal projector of FIG.

[Explanation of symbols]

1: Peltier element, 2: cooling fin, 3: radiation fin,
4 sirocco fan, 5 blast duct, 6 intake port,
7, 26: opening, 8: exhaust port, 19 to 21: liquid crystal panel, 25: housing.

Claims (1)

[Claims] 1. A liquid crystal projector comprising: a light source; a liquid crystal panel for modulating light from the light source; a projection optical system for projecting light modulated by the liquid crystal panel; and a cooling mechanism for cooling the liquid crystal panel. The cooling mechanism is a blower that forcibly sucks air outside the housing of the liquid crystal projector, a blower duct that guides the cooling air drawn by the blower to the liquid crystal panel, and an electronic cooling element that absorbs heat at one end and generates heat at the other end. And a cooling fin disposed in the air duct and in thermal contact with the heat absorbing side of the electronic cooling element, and a radiation fin in thermal contact with the heat generating side of the electronic cooling element.