Analysis on heat dissipation structure design of LED lamps

There are three main ways of heat dissipation: conduction, convection and radiation. For bulb and spotlight lamps, conduction plays a major role. In order to obtain good heat conduction effect, Thermal Conduction materials should be reasonably used in the three heat conduction links, and convection heat dissipation and heat radiation should be improved as much as possible. Heat source is very important for heat conduction. Heat source comes from two parts: light source and power supply. For the heat of the light source part, attention should usually be paid to the effective contact area between the light source PCB and the bonding surface of the heat sink. The larger the effective contact area, the better the heat dissipation. In addition, it should be noted that the heat conduction interface between different media should be as smooth as possible; The bonding between heat conductors should be close enough, and the gap between the contact surfaces of the fitting parts should be as small and small as possible. In the design of heat conduction of lamps, a good heat conduction channel should reduce the thermal resistance between PCB, heat conduction medium and heat sink and increase the effective contact surface between the three, and select the heat conduction medium with higher heat conduction rate. Natural convection also requires effective heat exchange area, so in general, appropriate roughening of the outer wall of the heat sink can increase the effective heat exchange area; In addition, the thickness of the paint and the thermal conductivity and radiation performance of the paint should be considered when spraying different colors. Generally, in order to increase the heat exchange area of the radiator, we adopt a fin structure. The normal effective heat exchange area is 50- 60. The fin radiator can determine the effective heat transfer performance according to the Fin efficiency and fin spacing. In natural convection, the power supply will also generate heat, because the power supply of bulb and spotlight is generally placed inside the lamp cavity, and the power supply can be dissipated by using media such as heat conducting potting adhesive or heat conducting mud. For the superimposed thermal field, it is suggested to increase the air layer between the power supply and the fitting platform of the LED light source and the PCB to form an air partition and weaken the superposition effect of the thermal field. In addition, thermal radiation is an energy transfer that all objects are carrying out at any time, and the radiation intensity of different materials is different. Generally, the radiation intensity of cold color objects is lower than that of warm color objects, and the radiation intensity of rough objects is higher than that of smooth objects. Generally, the radiation heat transfer of bulbs and spotlights is small and can be approximately ignored. To sum up, the reasonable collocation of light source, PCB, radiator and power supply should be considered for the heat dissipation of LED bulb and spotlights, and the selection and design of heat dissipation structures should be carried out according to different lamps and heat dissipation standards, avoid unnecessary waste of materials and costs caused by blind use of large heat sinks or high thermal conductivity materials.