How to effectively improve the heat dissipation performance of LED components

　　There are three ways of heat propagation: "heat conduction", "convection" and "thermal radiation". The propagation of lattice vibrations and the movement of free electrons in metals belong to "heat conduction", heat transfer through fluid movement belongs to "convection", and heat transfer through electromagnetic waves is "thermal radiation".

　　The advantage of heat radiation is that it can release heat when the casing is airtight and thin, and heat cannot be transferred by convection. Some technicians have known this advantage for a long time, but there are few precedents for making full use of it. However, recently, there has been an increase in LED lighting products that use heat radiation. Among them, a Japanese lighting fixture company has applied it to a variety of uses, from large LED lighting fixtures such as projectors to small products such as desk lamps.

　　By using heat radiation to dissipate heat, the heat dissipation efficiency of the projector can be improved, and a cooling fan is no longer required. Not using a cooling fan can reduce the risk of failure. In addition, since there is no need for multiple heat sinks, dust will not accumulate, saving the trouble of cleaning. When manufacturing the desk lamp, by using heat radiation to dissipate heat, the outer shell near the light source was successfully designed to be ultra-thin.

　　Ceramic circuit boards are all horizontally long hexagons with a length of 55mm and a width of 30mm, and a thickness of about 6mm. Multi-chip LED modules are fixed to the circuit board with screws. High-power LED modules with a maximum power of 19W can be used . Large products use multiple screws to fix the LED module to the ceramic circuit board, and small products use one. The material of the ceramic circuit board is alumina with a purity of 99.7% and a thermal emissivity of 0.97. The surface is smooth with an average roughness of 0.5μm. The LED module is directly fixed to the surface of the circuit board with screws.

　　Compared with metal circuit boards and printed circuit boards, ceramic circuit boards face the obstacle of high cost. However, if the mass production effect can be improved by using the commonality of ceramic circuit boards, the cost increase can be curbed to some extent. This requires increasing the number of mass production, but as of now, mass production has not yet started because companies are concerned about the high cost of ceramic circuit boards.

　　However, by using ceramic circuit boards, the total cost of heat dissipation components such as circuit boards and heat sinks used to mount LED modules can be reduced. I will also pay close attention to whether the idea of ​​reducing total costs can be popularized in the future. Perhaps the degree of popularization can be predicted by whether the number of LED lighting fixtures with simple shapes increases.