US20070157627A1

US20070157627A1 - Projection apparatus provided with a heatsink

Info

Publication number: US20070157627A1
Application number: US11/603,171
Authority: US
Inventors: Nien-Hui Hsu
Original assignee: Coretronic Corp
Current assignee: AIXIN TECHNOLOGIES LLC; CORECTRONIC Corp
Priority date: 2006-01-10
Filing date: 2006-11-22
Publication date: 2007-07-12
Also published as: TW200727067A; TWI306983B

Abstract

A heatsink for cooling a light valve, includes: a heat conduction member having a first section for coupling to the light valve and a second section; a thermoelectric cooler having a cold end connected to the second section of the heat conduction member and a hot end; a first cooling fin unit connected to the hot end of the thermoelectric cooler; and a fan disposed adjacent to the second section of the heat conduction member and the first cooling fin unit for generating an airflow in order to lower temperature within the heatsink.

Description

FIELD OF THE INVENTION

The invention relates to a projection apparatus, and more particularly to a heatsink for use in the projection apparatus in order to dissipate heat generated due to operation of the projection apparatus.

BACKGROUND OF THE INVENTION

FIG. 1 is a top sectional view showing a conventional projection apparatus 2 and includes a light source 8, an optical engine 6 and a heatsink 4. The optical engine 6 includes a light valve 602 receiving the light rays emitted from the light source 8 continuously during operation of the conventional projection apparatus and becomes hot intensively. In case, the intensive heat of the light valve 602 is not properly dissipated, the light valve 602 is tending to be ruined. The heatsink 4 is used to dissipate the intensive heat from the light valve 602.
The heatsink 4 includes a cooling fin unit 402 mounted directly onto the light valve 602 so as to cause a free convection to lower the temperature of the outer surface of the light valve 602. In the event the free convection provides poor dissipation effect, a fan 404 is employed to enhance the convection in order to lower the ambient temperature of the cooling fin unit 402. Such type of heat dissipation method is known as “force convection”.
For a projection apparatus 2 using high watt as power source, the light valve 602 becomes intensively hot and the fan 404 provides a limited heat dissipating effect. For example, in a projection apparatus 2 with 5000 lumens, the light valve 602 has a temperature of 65° C. at the outer surface thereof while a portion of the cooling fin unit 402 in contact with the outer surface of the light valve 602 has 53° C. When the environmental temperature is 35° C., there is a large temperature difference of 18° C. between the cooling fin unit 402 and the environmental temperature. In order to minimize the temperature difference, the rotation power of the fan 404 is increased. However, the increase in the rotation power generates noise in addition to extra production cost. As a matter of fact, utilization of the fan 404 eliminates the problems encountered by the projection apparatus having 3600 lumens below. Utilization the fan 404 cannot solve the heat dissipation problems encountered by the projection apparatus having 3600 lumens and above.

SUMMARY OF THE INVENTION

It is the object of the present invention to provide a heatsink for use in a projection apparatus. The heatsink has a structure to effectively dissipate the intensive heat of the light valve generated during operation of the projection apparatus.
In one aspect of the present invention, a heatsink is provided for cooling a light valve and includes: a heat conduction member having a first section for coupling to the light valve and a second section; a thermoelectric cooler having a cold end connected to the second section of the heat conduction member and a hot end; a first cooling fin unit connected to the hot end of the thermoelectric cooler; and a fan disposed adjacent to the second section of the heat conduction member and the first cooling fin unit for generating an airflow in order to lower temperature within the heatsink.
In a second aspect of the present invention, a projection apparatus is provided and includes: an optical engine including a light valve; and a heatsink. The heatsink includes: a heat conduction member having a first section coupled to the light valve and a second section, a thermoelectric cooler having a cold end connected to the second section of the heat conduction member and a hot end, a first cooling fin unit connected to the hot end of the thermoelectric cooler, and a fan disposed adjacent to the second section of the heat conduction member and the first cooling fin unit for generating an airflow in order to lower temperature within the projection apparatus.
Other aspects and advantages of the present invention as well as a more complete understanding thereof will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention. Moreover, it is intended that the scope of the invention be limited by the claims and not by the preceding summary or the following detailed description.
The following discussion shall constitute a brief and general overview of the invention. More specific details involving particular embodiments, best modes, and other important features of the invention will again be recited in the Detailed Description of the Preferred Embodiments section set forth below. All scientific terms used throughout this discussion shall be construed in accordance with the traditional meanings attributed thereto by individuals skilled in the art to which this invention pertains unless a special definition is provided herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of this invention will become more apparent in the following detailed description of the preferred embodiments of this invention, with reference to the accompanying drawings, in which:

FIG. 1 is a top sectional view showing a conventional projection apparatus with a heatsink;

FIG. 2 is a top sectional view showing the first embodiment of a projection apparatus of the present invention;

FIG. 3 is a fragmentary sectional view showing the second embodiment of the projection apparatus of the present invention;

FIG. 4 is a fragmentary sectional view showing the third embodiment of the projection apparatus of the present invention;

FIG. 5 is a fragmentary sectional view showing the fourth embodiment of the projection apparatus of the present invention;

FIG. 6 is a fragmentary sectional view showing the fifth embodiment of the present invention; and

FIG. 7 is a fragmentary sectional view showing a thermoelectric cooler employed in the heatsink of the projection apparatus according to the present invention.

DETAILED DESCRIPTIONS OF THE PREFERRED EMBODIMENTS

FIG. 2 is a top sectional view showing the first embodiment of a projection apparatus 30 of the present invention, and includes a light source 38, an optical engine 34 and a heatsink 32. The light source 38 is capable of generating light rays for the optical engine 34. The optical engine 34 includes a projection lens 37 and a light valve 36 that converts the light rays into image rays so that the projection lens 37 projects the image rays as an image onto a distal screen (not shown). The projection apparatus 30 in this embodiment is a Digital Light Processing projector while the light valve 36 is a Digital Micromirror Device. The heatsink 32 includes a heat conduction member 40, a thermoelectric cooler 42, a first cooling fin unit 44 and a fan 46.
The heat conduction member 40 has a first section 4002 coupled to the light valve 36 and a second section 4004. A cooling element serves as the heat conduction member 40 in the first embodiment.
The thermoelectric cooler 42 has a cold end 4202 connected to the second section 4004 of the heat conduction member 40 and a hot end 4204. The first cooling fin unit 44 is connected to the hot end 4204 of the thermoelectric cooler 42. Under this condition, convection is caused so as to guide the intensive heat from the light valve 36 toward the first cooling fin unit 44 when the projection apparatus 30 is under operation. In this embodiment, the light valve 36 and the thermoelectric cooler 42 are mounted on the same side of the heat conduction member 40.
Referring to FIG. 7, the thermoelectric cooler 42 includes a cold insulation layer 4212 defining the cold end 4202, a cold metal layer 4214, a semiconductor layer 4215, a hot insulation layer 4216 defining the hot end 4204, and a hot metal layer 4218 which are arranged horizontally. The cold and hot insulation layers 4212 4216 are disposed respectively outboard to the cold and hot metal layers 4214, 4218, which sandwich the semiconductor layer 4215 therebetween. The semiconductor layer 4215 preferably includes a plurality of vertically extending N-type semiconductor sections 82 and a plurality of vertically extending P-type semiconductor sections 84. Each P-type semiconductor section 84 is disposed between adjacent pair of the N-type semiconductor sections 82. Adding impurity into the Bismuth Telluride forms the present P-type and N- type semiconductor sections 84, 82. The cold and hot insulation layers 4212, 4216 are preferably made from a ceramic material. When the thermoelectric cooler 42 is powered on, the electrons flow through the P-type sections 84 towards the N-type sections 82 in order to absorb the heat from the cold end toward the hot end. The heat is absorbed or convection is caused whenever the electrons pass through a set of N-type semiconductor section 82 and P-type semiconductor section 84. It is noted that some dissipation paste is applied onto the cold and hot insulation layers 4212, 4216 and also on other layers in order to enhance the smooth convection.
The fan 46 is disposed adjacent to the second section 4004 of the heat conduction member 40 and the first cooling fin unit 44 for generating an airflow in order to lower temperature within the projection apparatus. In each embodiment of the present invention, the fan 46 exhausts or blows the heat effectively from the heat conduction member 40 and the first cooling fin unit 44.
The heat generated at the light valve 36 due to operation of the projection apparatus of the present invention is guided by the heat conduction member 40 toward the thermoelectric cooler 42, and is later passed toward the first cooling fin unit 44, thereby preventing the temperature of the outer surface of the light valve 36 from being raised. Since the first fin unit 44 has a large total outer surface, the heat is dissipated effectively into the ambient surrounding. In addition, the presence of the fan 46 enhances the heat dissipation ability.
FIG. 3 is a fragmentary sectional view showing the second embodiment of the present invention. The second embodiment has the structure similar to the previous embodiment, except in the heat conduction member 40. The heat conduction member 40 of the second embodiment preferably includes a second cooling fin unit 50 coupled to the light valve 36 and the cooling fins 51 extending outwardly from the second cooling fin unit 50. The heat generated at the light valve 36 is guided by the second cooling fin unit 50 to the thermoelectric cooler 42, which is latter guided toward the first cooling fin unit 44. The fan 46 cools down the first and second fin units 44 and 50.
FIG. 4 is a fragmentary sectional view showing the third embodiment of the present invention, and has the structure similar to the second embodiment, except in the second cooling fin unit 50. A first heat pipe 52 is embedded within the second cooling fin unit 50 in such a manner to extend through the first and second sections 4002, 4004 thereof. The employment of the first heat pipe 52 accelerates the convection from the light valve 36 toward the thermoelectric cooler 42.
FIG. 5 is a fragmentary sectional view showing a the fourth embodiment of the present invention and has the structure similar to the first embodiment except in the heat conduction member 40. The heat conduction member 40 includes a third cooling fin unit 60 coupled to the light valve 36, a fourth cooling fin unit 64 connected to the cold end 4202 of the thermoelectric cooler 42, and a second heat pipe 62 that is interposed between and that has two opposite ends connected to the third and fourth cooling fin units 60, 64 respectively. The third and fourth cooling fin units 60, 64 respectively define the first and second sections 4002, 4004 of the heat conduction member 40.
FIG. 6 is a fragmentary sectional view showing the fifth embodiment of the present invention and has the structure similar to the first embodiment except in the heat conduction member 40. The heat conduction member 40 is a third heat pipe 70 having two distal sections respectively defining the first and second sections, which are respectively connected to the light valve 36, and the thermoelectric cooler 42. The employment of the third heat pipe 70 quickens the convection from the light valve 36 toward the thermoelectric cooler 42 and later toward the first fin unit 44. The fan 46 cools down the first fin unit 44.
To summarize the above paragraphs, it is observable that due to employment of the heatsink 32 in the projection apparatus 30 of the present invention, the heat generated at the light valve 36 is effectively guided to the thermoelectric cooler 42, thereby preventing damage of the light valve 36 due to the raising temperature. Since the cold and hot insulation layers have a great temperature difference therebetween, the convection is quickening so as to reduce the burden to be carried by the fan 36.
While the present invention has been described in connection with what is considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.

Claims

1. A heatsink for cooling a light valve, comprising:

a heat conduction member having a first section for coupling to the light valve and a second section;

a thermoelectric cooler having a cold end connected to said second section of said heat conduction member and a hot end;

a first cooling fin unit connected to said hot end of said thermoelectric cooler; and

a fan disposed adjacent to said second section of said heat conduction member and said first cooling fin unit for generating an airflow in order to lower temperature within the heatsink.

2. The heatsink according to claim 1, wherein said heat conduction member includes a cooling element.

3. The heatsink according to claim 1, wherein said heat conduction member includes a second cooling fin unit and a first heat pipe embedded within said second cooling fin unit in such a manner to extend from said first section to said second section.

4. The heatsink according to claim 1, wherein said heat conduction member includes a third cooling fin unit disposed to said first section for coupling to the light valve, a fourth cooling fin unit disposed to said second section for connecting to said cold end of said thermoelectric cooler and a second heat pipe that is interposed between and that has two opposite ends connected to said third and fourth cooling fin units respectively, said third and fourth cooling fin units respectively defining said first and second sections of said heat conduction member.

5. The heatsink according to claim 1, wherein said heat conduction member is a third heat pipe having two distal sections respectively defining said first and second sections.

6. The heatsink according to claim 1, wherein the light valve is a DMD (Digital Micromirror Device).

7. The heatsink according to claim 1, wherein said thermoelectric cooler includes a cold insulation layer, a cold metal layer, a semiconductor layer, a hot insulation layer, and a hot metal layer which are arranged horizontally, said cold and hot insulation layers being disposed respectively outboard to said cold and hot metal layers, said cold and hot metal layers sandwiching said semiconductor layer therebetween, said cold and hot insulation layers being made from a ceramic material.

8. The heatsink according to claim 1, wherein the light valve and said thermoelectric cooler are mounted on a same side of said heat conduction member.

9. A projection apparatus comprising:

an optical engine including a light valve; and

a heatsink including

a heat conduction member having a first section coupled to said light valve and a second section,

a thermoelectric cooler having a cold end connected to said second section of said heat conduction member and a hot end,

a first cooling fin unit connected to said hot end of said thermoelectric cooler, and

a fan disposed adjacent to said second section of said heat conduction member and said first cooling fin unit for generating an airflow in order to lower temperature within the projection apparatus.

10. The projection apparatus according to claim 9, wherein said heat conduction member includes a cooling element.

11. The projection apparatus according to claim 9, wherein said heat conduction member includes a second cooling fin unit and a first heat pipe embedded within said second cooling fin unit in such a manner to extend from said first section to second section.

12. The projection apparatus according to claim 9, wherein said heat conduction member includes a third cooling fin unit disposed to said first section for coupling to the light valve, a fourth cooling fin unit disposed to said second section for connecting to said cold end of said thermoelectric cooler and a second heat pipe that is interposed between and that has two opposite ends connected to said third and fourth cooling fin units, said third and fourth cooling fin units respectively defining said first and second sections of said heat conduction member.

13. The projection apparatus according to claim 9, wherein said heat conduction member is a third heat pipe having two distal sections respectively defining said first and second sections.

14. The projection apparatus according to claim 9, wherein said light valve is a DMD (Digital Micromirror Device).

15. The projection apparatus according to claim 9, wherein said thermoelectric cooler includes a cold insulation layer, a cold metal layer, a semiconductor layer, a hot insulation layer, and a hot metal layer which are arranged horizontally, said cold and hot insulation being disposed respectively outboard to said cold and hot metal layers, said cold and hot metal layers sandwiching said semiconductor layer therebetween, said cold and hot insulation layers being made from a ceramic material.