Improved Design
The traditional heat dissipation technology is divided into active heat dissipation and passive heat dissipation. The heat sink belongs to passive heat dissipation, that is, relies on natural convection of air to dissipate heat, while active heat dissipation includes heat pipe, thermoelectric refrigeration technology, nano heat transfer technology, micro spray heat dissipation technology, and micro channel heat dissipation. Technology, fans, temperature plates, cold plates, etc. The idea of improving the heat dissipation structure of the lamp is as follows: firstly, the circuit board can be hollowed out, then the size of the heat sink is optimized. Finally, the influence of the interface material on the heat dissipation process is studied, and three other schemes are designed: Install a heat pipe on the heat sink, add a fan, and change the heat sink to a temperature equalizing plate material. After comparing and analyzing the simulation results of these schemes, this study puts forward feasible suggestions.
Circuit board hollowing scheme
The improved design should follow the general principle of LED heat dissipation design: the smaller the structural layer, the better the thickness of the layer is, the better the layer thickness is. The larger the area of the layer, the better the thermal conductivity of the material is. For the LED lamp, the circuit board is hollowed out to directly connect the heat sink and the heat sink, thereby reducing the circuit board layer and the thermal silica layer, and is more favorable for heat conduction.
The improved thermal network model reduces the board layer and a layer of thermal grease. The heat conduction line is a chip - thermal grease - copper heat sink - thermal silica gel - heat sink - environment.
Due to the inconsistent layout of the LED chips, the temperature distribution of the various parts in contact with them is not uniform. In addition, since the temperature field distribution of each layer is not uniform, the temperatures of adjacent portions may overlap, so the temperature band of each layer uses the difference between the highest temperature and the lowest temperature of the portion.
From the simulation results, the junction temperature can be read as 51.1226 °C, which is much lower than the unmodified model temperature, and within the allowable range, the improved heat dissipation structure meets the heat dissipation requirements, which proves the feasibility of the improved heat dissipation structure. Sex.
Heat sink optimization
At present, the most used heat dissipation technology for high-power LED lamps is the heat sink, which uses a large heat dissipation area to convect heat. For heat sinks, shape, processing, size and material are several important factors that determine heat dissipation. The following is mainly to optimize the size of the heat sink.
Add heat pipe solution
The heat pipe is an excellent heat conducting component. The outside is a copper wall. The inside has a liquid absorbing core and a condensate. Through the cyclic change of the liquid and gas phases, the heat emitted by the LED is led out and dissipated. The application of the heat pipe on the LED has various forms, and the LED chip can be directly mounted on the top of the heat pipe end of the heat pipe, or can be processed into a flat plate type or a loop type. The heat pipe is characterized by the ability to transfer heat to a remote, easily dissipated location, which is convenient and flexible in practical applications.
The simulation results show that the junction temperature of the chip is reduced by 2.24 °C after the heat pipe is installed. It can be seen that the installation of the heat pipe is beneficial to the reduction of the junction temperature. In the future research work, it is also possible to try to change the installation position or size of the heat pipe to obtain the junction temperature reduction. In the future research work, you can also try to change the heat pipe installation position or size to get
Interface material optimization
The thermal resistance is a comprehensive parameter reflecting the ability to block heat transfer, which is equal to the ratio of the temperature difference to the dissipated power on the heat flow path, in K/W. When heat is transferred inside the object by heat conduction, the ratio of the thermal resistance power encountered is expressed in K/W. When heat is transferred inside the object by heat conduction, the thermal resistance encountered is in contact with the thermal resistance. In the manufacturing process of the lamp, the interface material such as thermal silica gel or silver glue is used to reduce the contact thermal resistance, but the interface materials themselves The thermal conductivity is not high, causing a bottleneck in the heat transfer process. In response to this thermal phenomenon, this study studied the interface material between the chip and the copper base, and selected several interface materials with different thermal conductivity to simulate the heat distribution.
The thermal conductivity of the interface material is slightly increased, and the junction temperature will be greatly reduced. Therefore, increasing the thermal conductivity of the interface material has a great effect on the heat dissipation of the LED. More energy should be placed on the design and selection of better interface materials to reduce The interface material is the influence of this thermal bottleneck.