CN101315927B - A high-power LED phase-change heat sink structure - Google Patents

Abstract

The invention discloses a high-power LED phase-change heat sink structure. The heat sink body of the structure is a circular or square structure with a cavity. There is a boiling structure and a low-temperature boiling heat transfer medium in the cavity. The sealing end cover is placed At the upper end of the heat sink body, it is closely connected with the heat sink body to form a closed cavity. The inner surface of the sealing end cover is a condensation structure, and the cavity is sealed into a vacuum state; at least one high-power LED chip is fixed on the lower end of the heat sink body, and the electrodes are located at On the outside of the phase change heat sink, the phase change heat sink, electrodes and lenses are connected through encapsulation resin, and the high-power LED chips and electrodes are directly connected through gold wires. The invention realizes the heat isothermal effect of the heat sink body by using the liquid-gas phase change of the working fluid to reduce the temperature difference between the upper and lower ends of the heat sink, effectively export the heat generated by the high-power LED chip, and realize the integration of high-power LEDs and high-efficiency heat dissipation devices. It has the advantages of light weight, high power, simple structure, high heat dissipation efficiency, long life, and no extra energy consumption.

Description

A high-power LED phase-change heat sink structure

technical field

The invention relates to a high-power LED device, in particular to a high-power LED phase-change heat sink structure capable of effectively dissipating heat generated during high-power LED operation.

Background technique

Compared with incandescent lamps and fluorescent lamps, LEDs have been widely used in automotive lighting, decorative lighting, mobile phone flashlights, large and medium sizes, namely NB and LCD due to their small size, full solid state, long life, environmental protection, and power saving. -In the light source modules of display screens such as TVs, it has become one of the most promising high-tech fields in the 21st century.

LED is a photoelectric device, only 15%-25% of the electrical energy is converted into light energy during its working process, and the rest of the electrical energy is almost converted into heat energy, which increases the temperature of the LED; for a single LED, if the heat is concentrated in a small size Small chips that cannot be effectively dissipated will cause the temperature of the chip to rise, causing non-uniform distribution of thermal stress, chip luminous efficiency and phosphor lasing efficiency decrease. Studies have shown that when the temperature exceeds a certain value, the failure rate of the device will rise exponentially, and the reliability will drop by 10% for every 2°C increase in the component temperature. Near room temperature, for every 1°C increase in temperature, the luminous intensity of the LED will decrease by about 1%. When the device rises from the ambient temperature to 120°C, the brightness will drop by as much as 35%. When multiple LEDs are densely arranged to form a white light lighting system, the problem of heat dissipation is even more serious. Therefore, solving the problem of heat dissipation has become a prerequisite for the application of power LEDs.

Contents of the invention

The purpose of the present invention is to solve the problem of packaging and heat dissipation of high-power LEDs, and propose a phase-change heat sink structure for high-power LEDs. The designed high-power LED phase-change heat sink structure can use the liquid-gas phase change of the working fluid to realize the thermal isothermal effect of the heat sink body to reduce the temperature difference between the upper and lower ends of the heat sink, thereby effectively exporting the heat generated by the high-power LED chip, and realizing The integrated package of high-power LED and heat-dissipating package structure is suitable for mass production.

The purpose of the present invention and its main technical problems are solved through the following technical solutions:

A high-power LED phase-change heat sink structure, including a sealed end cover, a heat sink body, a high-power LED chip, gold wire, electrodes and packaging resin; the heat sink body is a circular or square structure with a cavity, and the cavity There is a boiling structure and a low-temperature boiling heat transfer medium inside. The sealing end cover is placed on the upper end of the heat sink body, and is closely connected with the heat sink body by welding or cementing to form a closed cavity. The inner surface of the sealing end cover is a porous structure; the cavity is sealed into a vacuum state; the boiling structure is a porous structure or groove structure, located at the lower end of the cavity; at least one high-power LED chip is fixed on the lower end of the heat sink body outside, and the electrodes are located outside the phase change heat sink, and the phase change heat sink and electrodes pass through the packaging resin Connected together, the high-power LED chips and electrodes are directly connected by gold wires to form a path.

In order to further realize the object of the present invention, the sealing end cover is a circular structure and placed on the upper end of the phase change heat sink.

The sealing end cap is a circular structure and placed in the phase change heat sink.

The sealing end cover is a square structure and placed in the phase change heat sink.

The boiling structure is made by sintering copper powder, which means first putting copper powder into the cavity formed by the sealing end cover and the heat sink body, reserving more than 10% of the cavity volume, then sintering, and sealing after sintering.

The low temperature boiling heat transfer medium is pure water, ethanol or acetone.

The high-power LED chips are multiple chips, and the multiple high-power LED chips are connected in parallel or in series.

Compared with the prior art, the present invention has obvious advantages and beneficial effects:

(1) The high-power LED phase-change heat sink structure used in the present invention realizes the thermal isothermal effect of the heat sink body to reduce the temperature difference between the upper and lower ends of the heat sink, and can effectively transfer the heat generated by the LED work to the external environment. In the middle, the heat dissipation capacity of the LED package is greatly improved;

(2) The boiling structure and the micro-groove structure of the phase change heat sink of the present invention can increase the boiling area and enhance the heat conduction effect;

(3) According to different requirements, the phase-change heat sink structure and the sealing end cap of the present invention can be designed into various structures and sizes such as square, circular, etc., so as to design various LED heat dissipation schemes;

(4) The present invention can weld or fix high-power LED chips in different quantities and different arrangements such as square and circular according to the designed phase-change heat sink structure size, which has adjustability and expands the application range of this structure;

(5) The manufacturing and packaging procedures of the structure described in the present invention are simple, and the packaging resin is used for integrated packaging, which is easy to realize industrialization;

(6) The structure of the present invention can continue to add other peripheral heat dissipation devices for multi-stage heat dissipation.

Description of drawings

Fig. 1 is a schematic structural diagram of a high-power LED phase-change heat sink of the present invention;

Fig. 2 is a schematic structural view of a sealed end cover and a phase change heat sink according to Embodiment 1 of the present invention;

Fig. 3 is a schematic structural diagram of a sealed end cover and a phase change heat sink according to Embodiment 2 of the present invention;

Fig. 4 is a schematic structural diagram of a sealed end cover and a phase change heat sink according to Embodiment 3 of the present invention;

Fig. 5a is the square layout form of the high-power LED chip described in the present invention;

Fig. 5b is a circular layout form of high-power LED chips in the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments, but the embodiments of the present invention are not limited thereto.

Example 1

As shown in Figures 1 and 2, the phase-change heat sink and packaging structure of a high-power LED includes a sealed end cover 1, a heat sink body 2, a high-power LED chip 3, a gold wire 4, a boiling structure 5, and a Quality 6, electrode 7 and lens 9, the sealing end cover and the heat sink body are circular structures with cavities, which are closely connected by welding or cementing to form a closed cavity, which is sealed into a vacuum state, and the cavity has The boiling structure 5 and the low-temperature boiling heat transfer medium 6; the sealing end cover 1 and the LED mounting aluminum substrate can be connected together by screws; the outside of the lower end of the heat sink body 2 and the outside of the sealing end cover 1 are both planar structures. The boiling structure 5 is in the form of copper powder sintering. First put the copper powder into the cavity of the sealing end cover 1 and the heat sink body 2, reserve 10% of the cavity volume, and then sinter and seal after sintering; The thermal working medium 6 is pure water. As shown in FIG. 5 a , there are multiple high-power LED chips 3 arranged in a square, and the multiple high-power LED chips 3 are fixed on the small end of the heat sink body 2 by welding or other means in parallel or in series. The high-power LED chip 3 and the electrode 7 are directly welded together through the gold wire 4; The lens 9 is made of a transparent material and plays a role in protecting the LED. The low-temperature boiling heat-transfer working medium 6 is pure water; the heat generated by the high-power LED chip 3 is transferred from the boiling structure 5 at the small end (ie the lower end) of the heat sink body 2 and the low-temperature boiling heat-transfer working medium 6 through the liquid-gas phase change of the working medium. heat transfer out. Its working principle is: the heat generated by the LED chip is transferred to the boiling structure 5 in the cavity through the lower end of the heat sink body, and the low-temperature boiling heat transfer working medium 6 in the cavity is heated and vaporized to transfer the heat to the sealing end cover, and the sealing end cover is then It is connected with other heat sinks for heat dissipation. The inner surface of the sealing end cover is porous structure, which is used to cool the vaporized substance into a liquid state. The liquid working medium returns to the heat sink body through the gross suction of the porous structure, thus forming a circulating state.

Example 2

As shown in Figure 3, a high-power LED phase-change heat sink and sealing end cap 1 of the packaging structure adopts a circular structure, is placed in the heat sink body 2, and is connected to the heat sink body 2 by welding or bonding. Together, the heat sink body 2 and the LED mounting aluminum substrate can be connected together by screws; the lower end of the heat sink body 2 adopts a circular structure, and the boiling structure 5 is made of porous material sintered, and the porous material is commercial foamed copper or aluminum foam. The sintering method is the same as copper powder sintering. The low temperature boiling heat transfer working medium 6 is acetone. As shown in FIG. 5 b , the high-power LED chips 3 are arranged in a circle, and are fixed on the lower end of the heat sink body 2 by welding in parallel or in series. Others are with embodiment 1.

Example 3

As shown in Figure 4, a high-power LED phase-change heat sink and sealing end cap 1 of the packaging structure adopts a square structure, is placed in the heat sink body 2, and is connected with the heat sink body 2 by welding or gluing. , and the heat sink body 2 and the LED mounting aluminum substrate can be connected together by screws; the lower end of the heat sink body 2 adopts a square structure, and the boiling structure is in the form of a square groove, and the groove is processed by an ordinary machine tool at the lower end of the cavity. The high-power LED chip 3 is one piece, which is fixed on the lower end of the heat sink body 2 by welding, and the low-temperature boiling heat transfer medium 6 is ethanol; the others are the same as in the first embodiment.

The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Any person familiar with the method of this profession may use the technical content disclosed above to change or modify the equivalent embodiment of equivalent changes. , but any simple amendments, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solutions of the present invention still belong to the scope of the technical solutions of the present invention.

Claims (10)

1. A high-power LED phase-change heat sink structure, characterized in that: it includes a sealed end cover, a heat sink body, a high-power LED chip, gold wire, electrodes and packaging resin; the heat sink body is a circular shape with a cavity Or square structure, there is a boiling structure and low-temperature boiling heat transfer medium in the cavity, the sealing end cover is placed on the upper end of the heat sink body, and is closely connected with the heat sink body by welding or cementing to form a closed cavity, the inner surface of the sealing end cover is Porous structure; the cavity is sealed in a vacuum state; the boiling structure is a porous structure or a groove structure, located at the lower end of the cavity; at least one high-power LED chip is fixed at the lower end of the heat sink body, and the electrodes are located outside the phase change heat sink. The sink and the electrodes are connected together by encapsulation resin, and the high-power LED chip and the electrodes are directly connected by gold wires to form a path. 2. The high-power LED phase-change heat sink structure according to claim 1, characterized in that: the sealing end cap is a circular structure and placed on the upper end of the phase-change heat sink. 3. The high-power LED phase-change heat sink structure according to claim 1, characterized in that: the sealing end cap is a circular structure and placed inside the phase-change heat sink. 4. The high-power LED phase-change heat sink structure according to claim 1, characterized in that: the sealing end cap is a square structure and placed inside the phase-change heat sink. 5. The high-power LED phase-change heat sink structure according to claim 1, characterized in that: said boiling structure is made by sintering copper powder, which means first putting copper powder into the space formed by the sealing end cover and the heat sink body. In the cavity, more than 10% of the cavity volume is reserved, and then sintered, and sealed after sintering. 6. The high-power LED phase change heat sink structure according to claim 1, characterized in that: the low temperature boiling heat transfer medium is pure water, ethanol or acetone. 7. The high-power LED phase-change heat sink structure according to claim 1, characterized in that: the high-power LED chips are single or multi-chip, and the multiple high-power LED chips are connected in parallel or in series. 8. The high-power LED phase-change heat sink structure according to claim 1, wherein the boiling structure is made by sintering copper powder. 9. The high-power LED phase-change heat sink structure according to claim 1, characterized in that: the boiling structure is made of porous material sintered, and the porous material is copper foam or aluminum foam. 10. The high-power LED phase-change heat sink structure according to claim 1, wherein the groove structure is a machined groove structure.

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