The main points of the design of LED film and television lights
1. Optical design
LED is a point light source, as the name implies, it is the light emitted by a point, and its characteristic is that there is light only in one direction. If you want to use this special light source as a studio light, you must deal with the light source to a certain extent and turn this relatively concentrated point light source into astigmatism with a certain angle to meet the requirements and objectives. Generally, straw hat LEDs are used to change the light from a concentrated point light source into an astigmatic light source with a certain angle. At the same time, its light attenuation effect is also very small, which improves the utilization rate of light. LED film and television lights are divided into LED film and television flat lights and LED film and television spotlights. When LEDs are used in LED film and television flat lights, although the straw hat LED has diffused and softened the light, the light is still relatively concentrated, and a soft light board is usually used to further improve the light. Soft, the light meets the requirements of studio lighting.
2. The difference between high-power and low-power LEDs
At present, the power of a single LED lamp bead can reach more than 200W, but its cost performance is lower than that of low-power LED lamp beads. For example, the LED film and television flat light uses a lot of 0.06W single LED small beads, and its brightness can reach 7lm. According to 6lm, its lumen is 102lm/W; and the power of 1W LED lamp beads can reach 80lm. , Its lumen should be less than 80lm/W. At the same time, the cost of high-power LEDs is higher than that of low-power. This comes from two aspects, one is the cost of the LED itself, and the other is that high-power LEDs require higher heat dissipation. It can be seen that the brightness of the LED film and television flat panel light with the same power is better if the low-power LED lamp bead is selected.
3. Heat dissipation design
LED is a semiconductor device, which has certain requirements on ambient temperature and working temperature, which affects the service life of the LED. Generally, the ambient temperature is lower than 20°C, and the PN junction temperature inside the LED is lower than 140°C. The power of LED video lamp is large, the number of LED lamp beads is large, and the arrangement is precise. Usually, the heat dissipation system needs to be designed to ensure the normal operation of the lamp. The thermal resistance of LED lamp beads is more different in the structure of packaging materials, which is directly related to the junction temperature and affects the service life of the LED and the light effect of the lamp. When designing the LED video panel light, the lamp beads should be distributed as evenly as possible to avoid heat source concentration. The higher the driving efficiency, the better, and the layout should be based on the principle of the largest heat source.
4. The current difficulties in heat dissipation design
Natural heat dissipation is too limited by space, and the improvement space is limited (radiation heat dissipation itself has little effect and is limited by space size).
Most of the heat dissipation design can only focus on the selection of lamp beads, the heat dissipation area, the interface contact thermal resistance, and the radiation heat dissipation, which is almost dead.
The breakthrough point of heat dissipation design is the heat dissipation design of the lighting system, which is the result of a combination of actual manufacturing, material accessories, structural modeling and various experiences in heat dissipation design.
