CN201827857U - Heat conducting structure of LED light source - Google Patents

Abstract

The utility model discloses a heat-conducting structure of an LED light source, which refers to a heat-dissipating substrate, on which a printed circuit board and its electrode pads are arranged on one or both sides of the surface, and a light-emitting element connected with the electrode pads. There are conductive lines distributed between the plates, which are characterized in that the top or both sides of the heat dissipation substrate are ceramic layers with dimensional stability and heat dissipation, and grooves are formed on it corresponding to the installation position of the heat sink of the light-emitting element; the heat dissipation substrate There is also more than one heat dissipation through hole penetrating from top to bottom to the bottom surface of the heat dissipation substrate, which is arranged around the groove and does not interfere with the conductive lines and electrode pads of the printed circuit board. Thermal vias for thermal channels. Applying the technical scheme of the utility model can effectively improve the thermal conductivity, electrical insulation performance and mechanical processing performance of the printed circuit board, enhance the high and low temperature impact resistance performance of LED products, improve the reliability and stability of the product, and be widely used in electronic devices. heat transfer medium.

Description

Heat conduction structure of LED light source

technical field

The utility model relates to a heat dissipation structure of an LED lighting lamp, in particular to a ceramic heat dissipation structure for LED light source packaging, which belongs to the technical field of LED applications.

Background technique

LED lighting sources have gradually begun to be widely used in many lamps and related products. They have the characteristics of long service life, high luminous efficiency and power consumption, and have the tendency to replace traditional lighting sources.

However, in the current development of packaging technology, the increase in power and the smaller and smaller volume make the center heat density higher and higher. The thermal resistance on the circuit board is the largest; at the same time, the heat sinks used in the heat dissipation substrate are almost all metals such as aluminum alloy or copper alloy. With the continuous increase of power and area, the thermal conductivity will also reach the saturation value. The temperature of the LED cannot be effectively reduced, and the long-term high temperature will cause the LED light decay to increase and the life to be shortened, increasing the possibility of LED failure. In addition, the current technical route mounts the LED light source chip and the heat dissipation substrate on a plane and electrically connects them. In this way, the heat dissipation substrate has the function of heat dissipation and electrical connection at the same time. If the heat dissipation substrate produces thermal stress and deformation at high temperature, it will inevitably cause a circuit short circuit or open circuit failure, making the entire light source product invalid. Therefore, the selection and structural design of the heat dissipation substrate are particularly important. .

The above phenomenon shows that some LED products can no longer meet the design needs of high-power LEDs only by package design, and must use multi-directional combination design to strengthen the heat dissipation function, reduce the impact of poor heat dissipation, and improve the light emission of light-emitting diodes. efficiency and service life. Therefore, how to choose printed circuit board material insulation and heat dissipation research has become an important direction of substrate design.

Contents of the invention

In order to overcome the deficiencies of the above-mentioned prior art, the purpose of this utility model is to package the light-emitting diodes on the composite structure of the heat dissipation substrate, provide a heat conduction structure of the LED light source, and utilize the heat dissipation through holes with a reasonable layout and the heat dissipation substrate with high thermal conductivity. Avoid heat energy from accumulating in the printed circuit board, thereby improving the heat dissipation and insulation safety of the LED light source, and prolonging the service life of the light-emitting element.

The purpose of this utility model will be achieved through the following technical solutions:

The heat conduction structure of the LED light source refers to a heat dissipation substrate, the upper surface of the heat dissipation substrate is provided with a printed circuit board and more than two electrode pads, and more than one light-emitting element connected to the electrode pads, the printed circuit board There are conductive lines distributed between the electrode pads of the board, and it is characterized in that: the top surface of the heat dissipation substrate is a ceramic layer with dimensional stability and heat dissipation, and the ceramic layer corresponds to the installation position of the heat sink of the light-emitting element. groove; the heat dissipation substrate is provided with more than one heat dissipation through hole penetrating from top to bottom to the bottom surface of the heat dissipation substrate. interference, and a heat dissipation channel communicating with each heat dissipation through hole is provided in the heat dissipation substrate.

Furthermore, in the heat conduction structure of the aforementioned LED light source, the heat dissipation substrate is a planar plate made of alumina, aluminum nitride or a complete ceramic material, or a regular-shaped or irregular-shaped columnar structure.

Furthermore, in the heat conduction structure of the aforementioned LED light source, the conductive lines of the printed circuit board are metal copper wires laid on the heat dissipation substrate, and the electrode pads thereof are partially provided with indium-gold alloy or gold-tin alloy.

Furthermore, in the heat conduction structure of the aforementioned LED light source, the insulating medium of the printed circuit board is one of epoxy glass fiber cloth bonding sheet or epoxy resin polymer.

Furthermore, in the aforementioned thermal conduction structure of the LED light source, the number of light emitting elements provided on the heat dissipation substrate is more than one, and the conductive lines and electrode pads between the light emitting elements are in a series or parallel structure.

The purpose of this utility model can also be achieved through the following technical solutions:

The heat conduction structure of the LED light source refers to a heat dissipation substrate. A printed circuit board and more than two electrode pads are provided on the upper and lower surfaces of the heat dissipation substrate, and more than two electrode pads are connected to the electrode pads. The light-emitting element has conductive lines distributed between the electrode pads of the printed circuit boards, and is characterized in that the heat dissipation substrate is a ceramic structure with dimensional stability and heat dissipation or a sandwich structure with ceramic top and bottom surfaces , and grooves are formed on both sides of the heat dissipation substrate corresponding to the installation position of the heat sink of the light-emitting element, and the grooves are misaligned relative to the two sides of the heat dissipation substrate; The heat dissipation through holes penetrating to the bottom surface of the heat dissipation substrate, the heat dissipation through holes are arranged around each groove, and do not interfere with the conductive lines and electrode pads of the printed circuit board, and are provided in the heat dissipation substrate to communicate with each heat dissipation Through-hole thermal channels.

Further, in the aforementioned heat conduction structure of the LED light source, the printed circuit boards on both sides of the heat dissipation substrate are relatively independent or connected to each other.

Implement the technical scheme of the utility model, its beneficial effect is reflected in:

(1) The thermal conductivity of ceramic heat dissipation substrate is higher than that of aluminum material, which has better thermal conductivity than aluminum material, and its weight is lighter than copper, so as to keep the radiator light, improve the heat dissipation performance of LED package substrate, and improve the temperature rise caused by Lead to the problem of large light decay and lifespan decline of LED chips;

(2) The thermal expansion rate of the LED heat dissipation substrate structure is small, and it has excellent heat dissipation performance, and its heat dissipation effect is excellent; the thermal expansion coefficient of the ceramic material is close to that of the LED chip, and the difference in the expansion change of the heated substrate is small, avoiding the fracture between the copper line and the metallized hole. cause damage;

(3) Strong thermal stress resistance: The ceramic heat dissipation substrate can withstand drastic changes in temperature without damage when used at room temperature, and has strong resistance to high and low temperature shocks, improving the reliability and stability of LED products;

(4) The ceramic heat dissipation substrate has high mechanical strength and toughness, and the manufacture of large-area printed boards can be realized on the ceramic heat dissipation substrate, which can effectively overcome the stress effect caused by different expansion coefficients between the conductive layer and the substrate. Withstand drilling, punching, cutting, etching and other processing;

(5) The anti-static performance is good. The ceramic or graphite material itself can effectively diffuse static electricity and prevent static electricity from breaking down electrical components.

Description of drawings

Fig. 1 is a schematic top view of the three-dimensional structure of an embodiment of the heat conduction structure of the LED light source of the present invention;

Fig. 2 is the sectional structural representation of line A-A in Fig. 1;

Fig. 3 is a schematic cross-sectional structure diagram of another embodiment of the heat conduction structure of the LED light source of the present invention.

Detailed ways

In order to make the technical features of the utility model and the beneficial effects after application clearer and easier to understand, the utility model will be further described in detail below in combination with several selected embodiments of the utility model and accompanying drawings. However, the invention can be broadly practiced in other embodiments than this detailed description. That is to say, the scope of the present utility model is not limited by the proposed embodiments, but should be based on the patent scope of the utility model.

As shown in Figure 1, it is an exploded view of the structure of the first preferred embodiment of the heat conduction structure of the LED light source of the present invention. The main structure of the heat conduction structure of the LED light source includes: a heat dissipation substrate 1, which can be a top surface with a size Stable and heat-dissipating ceramic layer or completely ceramic structure (this embodiment is preferably completely ceramic structure), a printed circuit board 3 is arranged on the heat dissipation substrate 1, and conductive lines and electrode pads are distributed on the upper surface of the printed circuit board 3 (conventional technology is not marked), the area where the heat sink of the light source is placed has a groove, and the light emitting element 2 or the light emitting element is attached to the area with the groove on the heat dissipation substrate 1, and the printed circuit board 3 has two or two above the electrode pads, and the electrodes at both ends of the light-emitting element are connected to the electrode pads on the printed circuit board 3 by metal wires. The heat dissipation substrate 1 is used to bear mechanical and thermal stress. In particular, the heat dissipation substrate 1 has several heat dissipation through holes 4, and the heat dissipation through holes 4 pass through the printed circuit board from top to bottom to reach the bottom layer of the heat dissipation substrate. The heat dissipation through holes 4 surround the heat sink of the light emitting element 2, And keep a certain distance from the conductive lines or electrode pads, and there are heat dissipation channels between the heat dissipation through holes 4 in the substrate to prevent local heat accumulation.

The heat dissipation substrate 1 is made of non-metallic ceramic material, and its shape is a flat plate, and it can also be a regular or irregular cylindrical structure, such as a rhombus or a square cylinder, as long as it can match the heat sink layer of the light emitting element 2 That's it. In addition, taking the planar plate structure in the preferred embodiment as an example, the material of the heat dissipation substrate 1 can be a polymer material, a ceramic material, or a composite material formed by the two, and the upper surface of the heat dissipation substrate 1 and the printed circuit board The lower surface of 3 corresponds to the lower surface, and is bonded with viscous substances such as epoxy glass fiber cloth or special high thermal conductivity epoxy resin polymer, so that the heat dissipation substrate 1 and the printed circuit board 3 are fixed and integrated. The electrodes on the upper surface of the printed circuit board 3 are connected to the light source electrodes one by one by soldering, and the upper and lower surfaces of the heat dissipation substrate 1 and the printed circuit board 3 and a plurality of heat dissipation through holes penetrating the two surfaces form a light-emitting diode. A heat dissipation substrate 1 with a composite structure.

The above-mentioned light-emitting element 2 is embedded in the hollow hole in the corresponding groove area of the printed circuit board 3, and is in contact with the non-metallic heat dissipation substrate 1 below. The heat dissipation substrate 1 is located directly below the heat sink of the LED light source 2, and the heat sink of the light source In full contact with the inner surface wall, the heat is evenly transmitted along the board surface, and the heat dissipation holes around the surroundings evenly convect the heat into the air.

The light-emitting element 2 and its electrodes are mounted and fixed on the surface electrode pads of the printed circuit board 3. The fixing method can be applied by solder paste, conductive silver glue or fixed by soldering. The electrodes or pins of the light source device Arranged in parallel or series structure.

The printed circuit board 3 is distributed with conductive lines and electrode pads, and its material selection generally adopts a high thermal conductivity epoxy glass fiber cloth bonding sheet or a special high thermal conductivity epoxy resin polymer, and its bottom thermal conductivity layer is a high thermal conductivity The ceramic substrate has strong dimensional stability, machinability and excellent heat dissipation. The heat sink of the light-emitting element 2 is in close contact with the surface of the ceramic substrate, and the periphery of the heat sink is closely attached to the insulating medium of the printed circuit board 3 to form a two-layer substrate structure, as shown in FIG. 2 .

After the above-mentioned printed circuit board 3 is pasted on the heat dissipation substrate 1, the conductive layer can be processed on the outer layer of the printed circuit board 3, and the conductive lines can be arranged, or the conductive layer can be completely covered on the outside of the insulating layer, and then the conductive line can be etched on the conductive layer. and a protective film is partially coated on the outside of the insulating layer, wherein the conductive circuit is made of metal copper, and the electrode pads can also be used or auxiliary metals such as gold, silver, and palladium are used to make conductive circuits on the copper layer.

In addition to the above substrate structure with a single conductive layer, the heat conduction structure of the LED light source of the present invention can also be a double-sided structure. As shown in FIG. 3 , conductive lines and light emitting elements 2 can also be arranged on the opposite surface of the heat dissipation substrate 1 . The structure of the heat dissipation substrate 1 is similar to the above-mentioned scheme, the difference is that a layer of printed circuit board is glued on the opposite surface of the ceramic heat dissipation substrate 1, and the light-emitting elements are mounted in the groove areas on both sides of the heat dissipation substrate that are misaligned. The areas with grooves are dislocated and cross-arranged, and the heat dissipation vias 4 are distributed in the gap between them, and do not interfere with the conductive lines and electrode pads on both sides, so as to achieve better heat dissipation effect.

In summary, the heat conduction structure of the LED heat dissipation substrate has good thermal conductivity, insulation performance and mechanical processing performance, which greatly improves the heat conduction effect of the LED light source, improves product reliability and stability, prolongs the service life of the product, and is widely used Used as a heat transfer medium for electronic devices to improve work efficiency.

Claims (7)

1. The thermal conduction structure of the LED light source refers to a heat dissipation substrate, and the upper surface of the heat dissipation substrate is provided with a printed circuit board and more than two electrode pads, and more than one light-emitting element connected to the electrode pads. Conductive lines are distributed between the electrode pads of the printed circuit board, and it is characterized in that: the top surface of the heat dissipation substrate is a ceramic layer with dimensional stability and heat dissipation, and the ceramic layer corresponds to the installation position of the heat sink of the light emitting element A groove is formed; the heat dissipation substrate is provided with more than one heat dissipation through hole penetrating from top to bottom to the bottom surface of the heat dissipation substrate. There is no interference, and a heat dissipation channel communicating with each heat dissipation through hole is provided in the heat dissipation substrate. 2. The thermal conduction structure of the LED light source according to claim 1, characterized in that: the heat dissipation substrate is a flat plate made of alumina, aluminum nitride or a complete ceramic material, or a cylindrical structure with a regular shape or an irregular shape . 3. The heat conduction structure of the LED light source according to claim 1, characterized in that: the conductive circuit of the printed circuit board is a metal copper wire laid on the heat dissipation substrate, and part of the electrode pad is provided with an indium-gold alloy or gold-tin alloy. 4. The heat conduction structure of the LED light source according to claim 1, characterized in that: the insulating medium of the printed circuit board is one of epoxy glass fiber cloth bonding sheet or epoxy resin polymer. 5. The thermal conduction structure of LED light source according to claim 1, characterized in that: the number of light-emitting elements provided on the heat dissipation substrate is more than one, and the conductive lines and electrode pads between the light-emitting elements are in series structure or Parallel structure. 6. The heat conduction structure of the LED light source refers to a heat dissipation substrate, and the upper and lower sides of the heat dissipation substrate are provided with a printed circuit board and more than two electrode pads respectively, and two or more electrode pads connected to the electrode pads. In the above light-emitting element, conductive lines are distributed between the electrode pads of the printed circuit boards, and it is characterized in that: the heat dissipation substrate is a ceramic structure with dimensional stability and heat dissipation, or the top surface and the bottom surface are all ceramics Sandwich structure, and grooves are formed on both sides of the heat dissipation substrate corresponding to the installation position of the heat sink of the light-emitting element, and the grooves are misaligned relative to the two sides of the heat dissipation substrate; the heat dissipation substrate is provided with more than one The heat dissipation through hole penetrates down to the bottom surface of the heat dissipation substrate. The heat dissipation through hole is arranged around each groove and does not interfere with the conductive lines and electrode pads of the printed circuit board, and a communication hole is provided in the heat dissipation substrate. Thermal channels for each thermal via. 7. The heat conduction structure of LED light source according to claim 6, characterized in that, the printed circuit boards on both sides of the heat dissipation substrate are relatively independent or connected to each other.

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