Patent Application
20080137337
This Non-provisional application claims priority under U.S.C. ยง119(a) on Patent Application No(s). 095145985, filed in Taiwan, Republic of China on Dec. 8, 2006, the entire contents of which are hereby incorporated by reference.
1. Field of the Invention
The invention relates to a heat dissipating module and a display apparatus utilizing the same, and more particularly to a heat dissipating module and a display apparatus utilizing the same applied to a light emitting diode.
2. Description of the Related Art
Because science and technology gradually progresses, electronic products must provide more functions. The variety and functionality of personal computers continually increases. Portable computers, PDAs, cell phones, a handheld computer are the topics of a great deal of research. Products with multiple functions, due to the integration of many electronic elements in one device, increases heat generation, and thus heat-dissipation efficiency directly affects product reliability and lifespan.
Take light emitting diodes (LED) as an example, heat dissipation for the LEDs is visually used several fins or heat pipes, typically connected to the rear of the light emitting diode array to actively or passively dissipate heat generated by the LEDs.
The heat pipe is an easy and efficient heat dissipating device, thus, they are extensively applied in a wide variety of heat dissipating electronic products. However, heat pipes employed in large-size rear projection televisions are not able to provide the required heat dissipating efficiency. Compared to fins, heat pipes can improve temperature uniformity of the LEDs, but the the length of the heat pipe is limited to 50 centimeters. In heat pipes over 50 centimeters in length, the working fluid in the heat pipe is unable to quickly return. Thus, heat pipes dry out easily, potentially causing damage. Thus, heat pipes are not employed in light emitting displays over 20 inches.
A detailed description is given in the following embodiments with reference to the accompanying drawings. The invention provides a light emitting diode heat dissipating module and a display apparatus utilizing the same. The invention improves the conventional heat pipe by eliminating length limitation of conventional heat pipes, and thus design flexibility is increased. Further, the temperature uniformity can be maintained between all LEDs so as to increase the display efficiency and reliability of the entire display apparatus. Additionally, the light emitting diode heat dissipating module of the present invention is relatively small and light.
The present invention provides a light emitting diode heat dissipating module including a plurality of light emitting diodes(LEDs), a pulsating heat pipe and a plurality of fins. The pulsating heat pipe is divided into a vaporizing section and a condensing section. The LEDs are disposed and completely on the pulsating heat pipe and located at the vaporizing section. The fins are connected to the pulsating heat pipe and are all located at the condensing section of the pulsating heat pipe.
The present invention provides a display apparatus including a housing, a display panel and a plurality of light emitting diode heat dissipating modules. The display panel is connected to the housing. All light emitting diode heat dissipating modules are installed in the housing. The light emitting diode heat dissipating module includes a plurality of LEDs, a pulsating heat pipe and a plurality of fins. The LEDs serve as a light source for the display panel. The pulsating heat pipe is divided into a vaporizing section and a condensing section. The LEDs are disposed and completely on the pulsating heat pipe and located at the vaporizing section. The fins are connected to the pulsating heat pipe and are all located at the condensing section of the pulsating heat pipe.
The present invention further provides a heat dissipating display apparatus utilizing the above-mentioned light emitting diode heat dissipating modules. The light emitting diode heat dissipating modules are installed at the rear of the display panel, and the LEDs are disposed between the heat dissipating modules and the display panel. The pulsating heat pipe is formed with a closed space filled with a working fluid W, like an inorganic compound, pure water, alcohol, ketone, liquid metal, organic compound or a combination thereof. When the working fluid at the vaporizing section absorbs heat generated by the LEDs, a bubble is generated and boiled during evaporation. The bubble pushes the working fluid from the vaporizing section to the condensing section to discharge heat, and then returns to the vaporizing section to complete a cycle.
The LEDs are connected to the pulsating heat pipe by direct mounting, adhering, joining, or welding, or fixed by other equivalent methods. The pulsating heat pipe has a cross section with an outer shape, and the outer shape is semicircular, rectangular, triangular, quadrilateral, trapezoidal, pentagonal, hexagonal, octagonal, other equilateral scalene polygon. Also, in the cross section of the heat pipe can be seen to include an inner shape and the outer shape. The inner shape is circular and the outer shape is rectangular.
The pulsating heat pipe is made by a material with high heat conductivity, such as aluminum; copper, titanium, molybdenum, silver, stainless steel, carbon steel, or other alloys. Also, the display apparatus has a fan installed near the fins for increasing heat convection efficiency. Further, the display apparatus has a circuit board electrically connected to the LEDs, and the circuit board includes a comb structure having a plurality of teeth. Each light emitting diode heat dissipating module can be disposed at a site between each two adjacent teeth of the comb structure.
The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:
The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims.
The operating principle of the pulsating heat pipe 22 is disclosed as follow. Referring to
When the working fluid W at the vaporizing section V of the pulsating heat pipe 22 absorbs heat generated by the LEDs 21, a bubble B is generated and boiled during evaporation. Because the bubble at the vaporizing section V continuously increases, a differential pressure is generated between the vaporizing section V and the condensing section C. As the results, the bubble B pushes the working fluid W from the vaporizing section V to the condensing section C for heat discharge. The working fluid W then returns to the vaporizing section V, and thus the flow cycle of the working fluid W is completed. The flow cycle of the working fluid discharges heat from the LEDs efficiently and continuously.
Compared to a conventional heat pipe, the capillarity and length of the conventional heat pipe are limited. Due to generation and elimination of the bubble B forms a pumping force for driving the working fluid W, the length of the pulsating heat pipe 22 can reach several meters compared to the conventional 50 centimeters, thus increasing design flexibility.
Referring to
The LEDs 21 are connected to the pulsating heat pipe 22 by direct mounting so as to decrease the contact thermal resistance between the LEDs 21 and the pulsating heat pipe 22, thereby increasing heat conductivity of the light emitting diode heat dissipating module 20. However, the present invention is not limited thereto, for example, the LEDs 21 can be connected to the pulsating heat pipe 22 by adhering, joining, or welding, or fixed by other equivalent methods:
The light emitting diode heat dissipating module 20, the LEDs 21, the pulsating heat pipe 22 and the fins 23 is similar to
As for a large-size rear projection television, more than hundreds of LEDs are necessary to be applied in providing lights. Thus, several light emitting diode heat dissipating modules 20 are disposed at the rear of the display panel 32, and the LEDs 21 face to the display panel 32 for illuminating as a light source for the display panel 32. When heat generated by the LEDs 21, heat can be quickly transmitted to the condensing section C of the pulsating heat pipe 22 via the pulsating heat pipe, and the fins located at the condensing section. C increases heat dissipating area. Also, the fan 33 installed near the fins 23 increases heat convection efficiency by providing airflows.
For simplicity,
However, the present invention is not limited thereto. For example,
Compared with the conventional heat pipe has limitations of capillarity and length, the pulsating heat pipe 22 of the present invention can reach to several meters, rather than the conventional 50 centimeters. Additionally, because the pulsating heat pipe 22 can be arranged at any angles without limitation, the design flexibility is enhanced. Due to the temperature uniformity of vaporizing section V of the pulsating heat pipe 22, the temperature of each light emitting diode is equalized. Thus, the display efficiency and reliability can be maintained. Compared with the conventional heat pipe, the light emitting diode heat dissipating module 20 decreases the weight and occupied space, so the light emitting diode heat dissipating module 20 of the present invention is relatively small and light.
While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.
| Number | Date | Country | Kind |
|---|---|---|---|
| 95145985 | Dec 2006 | TW | national |
