Analysis of the heat dissipation structure and principle of high-power LED energy-saving using thermally conductive silicone sheet and thermal grease

Analysis of the heat dissipation structure and principle of high-power LED energy-saving using thermally conductive silicone sheet and thermal grease

Because the core part of the LED lamp is the PN junction (using different doping processes, the P-type semiconductor and the N-type semiconductor are fabricated on the same semiconductor substrate through diffusion, and a space charge region is formed at their interface called PN junction) and the light energy is converted into heat energy by the absorber inside the PN junction and epoxy/silica gel. This heat has a huge side effect on the lamp, which will make the internal temperature of the LED lamp higher and lower, the brightness is lower and the life is longer. It is shorter and shorter, so good heat dissipation is the guarantee for LED lamps to maintain constant brightness and prolong life.

Next, let’s introduce the high-power LED package structure:
Because everyone has higher and higher requirements for LED light sources, in addition to different requirements for LED light output rate and light color, there are also different requirements for luminous intensity and other aspects. In order to meet customer needs and improve packaging technology, then Various chip manufacturers have also put forward higher requirements for packaging factories, and designed a packaging structure that can better meet customer needs, thereby improving the light utilization rate outside the LED.
Different application fields put forward higher requirements for LED light sources, in addition to different requirements for LED light emitting efficiency and light color, but also different requirements for light emitting angle and light intensity distribution. This not only requires the upstream chip factory to develop new semiconductor materials, improve the chip manufacturing process, and design chips that meet the requirements, but also puts forward higher requirements for the downstream packaging factory to design a package structure that meets a certain light intensity distribution to improve the light utilization outside the LED. Rate.
The existing heat dissipation technology consists of the following parts: heat dissipation aluminum profile, thermal conductive silicone sheet or thermal conductive silicone grease, thermal conductive ceramic sheet, insulating silicone sheet LED lamp components, electrodes, LED base, LED PN junction
The heat dissipation process of thermally conductive silicone is as follows: the heat source from the PN junction of the LED passes through the LED base to the solder paste soldering layer and then to the copper layer, through the insulating layer to the heat-dissipating aluminum plate and then to the thermally conductive silicone sheet or thermally conductive silicone grease. The heat is conducted to the heat-dissipating aluminum plate and dissipated, so that the entire heat-dissipating link is completed.

Generally speaking, the thermal conductivity of the base of the LED lamp is about 80W/mk; the thermal conductivity of the copper layer is 400W/mk, and the thermal conductivity of the aluminum plate is about: Iw/mk, the thermal conductivity of the LED lamp thermal silicone gasket or thermal grease The thermal conductivity is generally 0.8~5.0W/mk. The closer to the PN junction of the LED, the higher the heat flow density. In this way, the thermal conductive silicone sheet/thermal grease has already had the lateral heat conduction of the aluminum plate and the heat flow density of the insulating layer is high. From the heat flux density of thermal grease, it can be seen that the most difficult heat dissipation is the insulation layer of the aluminum plate.
Since the most difficult heat dissipation is the insulating layer on the aluminum plate, the copper layer and the insulating layer are drilled and removed, so that the aluminum substrate can be exposed, and then zinc is immersed on the exposed aluminum plate, and then nickel is plated on the zinc surface. , and then plated with copper on nickel, and then sprayed with tin or immersion gold on the copper. After processing, the coating has strong adhesion and good thermal conductivity. After the coating process, the LED is welded to the aluminum plate. After the welding is completed, the heat emitted by the PN junction of the LED passes through the LED base to the solder paste soldering block and then to the aluminum plate, and then passes through the thermal conductive silicone gasket or thermal conductive silicone grease of the LED lamp to conduct the heat to the heat dissipation aluminum profile and then dissipate into the air. After the insulating layer with very small thermal conductivity, the heat dissipation effect is greatly enhanced, and the temperature of the LED base is lowered, thereby prolonging the life and stability of the LED lamps.
Welcome to buy Lian Tengda thermal conductive materials, the company’s main business: thermally conductive silicone sheet, thermally conductive silicone grease, thermally conductive ceramic sheet, heat sink, thermally conductive silicone sheet, factory independent production, quality controllable, credit guarantee

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