LED flat panel light structure analysis and design considerations

With the development of LED lighting industry, LED flat panel lights, which are derived from LED backlight , have been loved by many people for their uniform light, no glare, and exquisite structure. After 2 years of design and development of flat panel lights, I will briefly talk about the structural design and precautions of flat panel lights, hoping to provide help to everyone.

The structure of the surface light source mainly includes the following materials

1. Aluminum frame

Appearance structure, and LED heat dissipation Main structure - generally use AL6063, aluminum extrusion die, low initial cost investment, beautiful surface treatment, good heat dissipation effect. I went to the exhibition a few days ago and found that some manufacturers began to make die-cast frames, so that the IP level can be higher, the light sealing is better, and the overall appearance is beautiful, but the initial investment in mold costs is high.

2. Diffuser plate

Evenly disperse the light of the light guide plate , and also play the role of shielding the dots. The diffusion plate generally uses acrylic 2.0 plate or PC material. The cost of acrylic is lower and the light transmittance is slightly higher than that of PC. Acrylic is brittle and has weak anti-aging performance. The price of PC is slightly more expensive, but it has strong anti-aging performance. After the diffusion plate is installed, the dots cannot be seen, and the light transmittance must be around 90%. The light transmittance of acrylic is 92%, and that of PC is 88%. You can choose the material of the diffusion plate according to your needs. Generally, acrylic materials are used.

3. Light guide plate

The side LED light is refracted through the dots to change the angle of the light and disperse it - the light guide plate is the heart of the flat panel light. The dot design is very important. If the dot design is not good, the overall light effect will be very poor. Generally, 1. The middle is bright and the two sides are dark. 2. There is a bright edge on the light-incoming side and the middle is dark. 3. The overall brightness is inconsistent when viewed from different angles. 4. The local dark area is obvious. A large part of the light effect of the light guide plate is in the design of the dots, followed by the selection of the plate. However, it is wrong to blindly pursue the brand of the plate, because many big brand manufacturers like Japan's Mitsubishi, most of their good plates are ordered by others, and many Mitsubishi plates flowing out of the market are mostly scraps, and their transmittance is low and not as high as their own plates. Therefore, the selection of the plate does not necessarily depend on the manufacturer of the plate. As long as the transmittance is high and the light efficiency is OK after testing , it is actually OK.

4. Reflective paper

Reflect the residual light from the back of the light guide plate - usually RW250

5. Rear cover

Sealed lamp body - generally AL aluminum, with a strong overall texture and can play a role in heat dissipation

6. LED light source

Generally, 3528 is used. Some people also use 5630 and 5050. 5630 and 5050 have low light efficiency and difficult dot design, poor versatility, but low cost. 3528 has high light efficiency and strong dot versatility. Generally, when you are just starting out, you can directly buy other companies' light guide plates and use them without re-proofing and designing.

7. Drive Power supply

Lamp driver - There are currently two power supply modes: 1. Directly use cross-current power supply (this mode has high efficiency, PF value up to 0.95, high cost performance) 2. Constant voltage with cross-current mode (stable performance, but low efficiency, high cost) This mode is generally designed for customers who require certification, because the lamp is a low-voltage lamp with 24V input, no safety regulations are required, and direct use of a safety-compliant power supply can be shipped to various countries

Issues that need to be paid attention to during the design and production process

1. The thinner the thermal conductive glue is, the better. It is best to use self-adhesive thermal conductive glue, otherwise it will affect the thermal conductivity.

2. The selection of diffusion plate. Now many flat panel lamps on the market generally choose a glossy and matte diffusion plate. This kind of diffusion plate has a disadvantage, which is that it has high static electricity and is easy to absorb dust and produce bright spots during the production process. In addition, dust will enter the lamp body through various channels during long-term use, which will cause dense bright spots in the lamp. In the early days, some people used double-sided diffusion diffusion plates. This kind of diffusion plate has good light-guiding effect and low static electricity, which can prevent dust from entering the lamp body and causing bright spots. However, the light transmittance of this kind of diffusion plate is low, only 85-88%. Whether to choose it depends on your own design.

3. When choosing LED lights , try to choose high-efficiency lights, because side-emitting flat panel lights have limitations in heat dissipation and luminous flux output. If the power is too high, heat dissipation will be affected, and the light efficiency will be low.

4. When sticking reflective paper on the light-incoming surface, try not to stick glue, as glue will absorb light and easily cause bright edges on the light-incoming surface. However, a large area of ​​the light guide plate needs to be glued a little, otherwise shadow strips will appear. This is because the reflective paper is not glued tightly and is loose and warped inside the lamp body.