JP2001312002A - LCD projector - Google Patents

Abstract

(57) [Object] To provide an optical device such as a liquid crystal projector having a highly efficient liquid crystal panel cooling structure which is advantageous for miniaturization and thinning. A heat absorbing section (5A) of a heat pipe (5) is thermally connected to a cooling fin (4) disposed on one side of an image forming optical system (3) including a plurality of liquid crystal panels for modulating and combining light from a light source and a dichroic prism. The heat radiating fins 6 are fixed to the heat radiating portion 5B of the heat pipe 5 penetrating the cover 2A by thermal contact, and the other side of the image forming optical system 3 is provided with a cooling fan 7. Exhaust port 7
B is disposed toward the image forming optical system 3. Cooling fan 7
Is introduced into the image forming optical system 3, passes through the cooling fins 4, circulates through the housing 25, and returns to the intake port 7 </ b> A of the cooling fan 7. The heat of the cooling fins 4 is deprived by the heat pipe 5 brought into contact with the cooling fins 4, and the cooling fins 4 are conveyed out of the housing 25 and radiated from the radiating fins 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal projector for enlarging and projecting an input image, and more particularly to a cooling mechanism for an image forming optical system including a plurality of liquid crystal panels for modulating and combining light from a light source and a cross dichroic prism. Things.

[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 enters the liquid crystal panel 19, where
2 is reflected by the condenser lens 17
And enters the liquid crystal panel 20. The blue light transmitted through the dichroic mirror 12 is reflected by the total reflection mirror 1.
4 and 15 and enter the liquid crystal panel 21 through the condenser lens 18. The dichroic prism 22 combines the respective color lights transmitted through the liquid crystal panels 19 to 21. The light synthesized by the dichroic prism 22 is projected by a projection lens 23 onto 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 the conventional liquid crystal projector, cooling air taken in from outside by an axial flow or a sirocco fan through an air filter is sent to the liquid crystal panels 19 to 21 and the optical elements in the vicinity thereof to be cooled. FIG. 4 (a),
4B and 4C are a front view, a plan view, and a side view, respectively, of the liquid crystal projector of FIG. FIG.
FIG. 4D is a side view of FIG. 4C with the axial fan removed. In FIG. 4, reference numeral 24 denotes an axial fan, 25 denotes a housing of the liquid crystal projector, and 26 denotes an opening provided in the housing 25.

[0006]

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 an axial flow or a sirocco fan. The present invention has been made in order to solve the above-described problems, and provides a liquid crystal projector which is capable of coping with high brightness by improving a cooling capacity as compared with a conventional one, has high quietness, and is maintenance-free. With the goal.

[0007]

SUMMARY OF THE INVENTION A liquid crystal projector according to the present invention comprises an image forming optical system including a light source, a plurality of liquid crystal panels for modulating and synthesizing light from the light source and a cross dichroic prism, and an image synthesized by a dichroic prism. An optical unit that includes a projection optical system that projects light and a cooling mechanism that cools the image forming optical system is hermetically sealed. The cooling mechanism is provided on one side orthogonal to the optical path of the image forming optical system, and sends a cooling air to the image forming optical system and forcibly circulates air in the optical unit. The cooling fin is provided on the other side surface orthogonal to the optical path of the system, and a heat pipe provided outside the optical unit and in thermal contact with the cooling fin at one end.

[0008]

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a configuration of a cooling mechanism of a liquid crystal projector according to an embodiment of the present invention. FIG. 1 is a perspective view of an external appearance of a partially cut optical unit of the liquid crystal projector according to the embodiment of the invention shown in FIG. It is arrow A sectional drawing. In the present invention, the cooling fins 4, as means for cooling the liquid crystal panels 19 to 21, the dichroic prism 22, and the optical elements in the vicinity thereof,
A cooling fan 7 including a heat pipe 5, a radiation fin 6, and an axial fan is used.

The heat pipe 5 is a heat transfer element having a structure in which an inner wall has a capillary structure, and a working pipe such as pure water or perfluorocarbon is sealed in a metal pipe having a vacuum inside. When heat is applied to one end (heat absorbing portion) of the heat pipe 5, the working fluid evaporates, becomes a steam flow, moves to the low temperature portion at the other end (radiating portion), and is cooled and condensed there. The condensed working fluid returns to the heat absorbing portion by capillary action. In this manner, the evaporation, movement, and condensation are repeated, and the heat applied to the heat absorbing section is transported to the heat radiating section.

As shown in FIG. 1 and FIG.
A plurality of liquid crystal panels 1 that modulate and combine light from (FIG. 3)
9 to 21 and one side surface orthogonal to the optical path of the image forming optical system 3 including the dichroic prism 22, that is, the housing 2
The heat absorbing portion 5A of the heat pipe 5 is fixed to a cooling fin (heat sink) 4 made of a metal having good thermal conductivity such as aluminum and formed in a honeycomb shape, which is disposed in the opening 26A of the heat pipe 5. At the same time, a heat dissipating fin (heat sink) made of a metal having good thermal conductivity such as aluminum is formed in a heat dissipating portion 5B of the heat pipe 5 which is fixed to the housing 25 and penetrates a cover 2A for closing the cooling fin 4. ) 6 is fixed by thermal contact.

The other side of the image forming optical system 3, that is, the opening 26B of the housing 25, has an exhaust port 7B of a cooling fan 7 composed of an axial fan facing the image forming optical system 3 in FIG. It is arranged as follows. 7A is an intake port of the cooling fan 7, and 2B is a cover fixed to the housing 25 and hermetically closing the cooling fan 7.

In the cooling mechanism configured as described above, the air in the housing 25 that is forcibly sucked from the intake port 7A of the cooling fan 7 is exhausted from the exhaust port 7B of the cooling fan 7,
The light is introduced into the image forming optical system 3. The cooling air passes through the cooling fins 4 as shown by arrows in FIG. 1, circulates through the inside of the housing 25, and returns to the intake port 7A of the cooling fan 7. At this time, the heat of the cooling fins 4 is taken away by the heat pipe 5 in which the heat absorbing portion 5A is brought into thermal contact with the cooling fins 4, and this heat is transferred to the heat radiating portion 5B of the heat pipe 5 penetrating through the cover 2A. Heat is radiated from the fins 6.

Therefore, the air circulating in the housing 25 is cooled to a temperature lower than the outside air temperature outside the housing 25,
The temperature of the image forming optical system 3 and the optical elements around the image forming optical system 3 can be reduced more efficiently than in the conventional case where cooling is performed using air outside the housing 25.

[0014]

According to the present invention, a cooling mechanism is provided in a sealed optical unit, and the cooling mechanism is provided with a cooling fan,
The cooling fins, heat pipes, and radiating fins make the LCD panel mounting bracket and surrounding structures also play a role in the cooling fins, efficiently cooling air flowing to the image forming optical system such as the liquid crystal panel. It can be cooled to a temperature lower than the outside air temperature outside the body. For this reason, it is possible to improve the cooling capacity as compared with the conventional cooling mechanism in which the outside air that has passed through the filter is taken in by the fan and directly hits the image formation optical system, and it is possible to cope with an increase in the brightness of the liquid crystal projector.

Further, since the cooling mechanism according to the present invention does not use outside air, dirt and dust which cannot be completely removed by the air filter do not adhere to the image forming optical system, and do not appear on the projection screen. A clear screen can be obtained. Furthermore, by assembling this optical unit in a clean room or the like, even if the optical unit is replaced in a place other than the clean room, no dust or the like enters the sealed optical unit, and the air filter is replaced. Maintenance-free liquid crystal projector can be provided.

Further, since the cooling fan is provided in the closed housing, the noise of the cooling fan does not leak to the outside and the quietness can be maintained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating 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 where the cooling mechanism of FIG. 1 is mounted on an optical unit of 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]

DESCRIPTION OF SYMBOLS 1 ... Optical unit, 2A, 2B ... Cover, 3 ... Image formation optical system, 4 ... Cooling fin, 5 ... Heat pipe, 6 ... Radiation fin, 7 ... Cooling fan, 25 ... Housing.

Claims (1)

[Claims] An image forming optical system including a light source, a plurality of liquid crystal panels for modulating and combining light from the light source and a cross dichroic prism, a projection optical system for projecting image light combined by the dichroic prism, and an image forming optical system A liquid crystal projector including a sealed optical unit including a cooling mechanism for cooling the system, wherein the cooling mechanism is disposed on one side surface orthogonal to the optical path of the image forming optical system and applies cooling air to the image forming optical system. A cooling fan for blowing air and forcibly circulating air in the optical unit; a cooling fin disposed on the other side orthogonal to an optical path of the image forming optical system; and a cooling fin disposed outside the optical unit. A liquid crystal projector comprising a fin and a heat pipe thermally contacted at one end.