Lamp beads
Usually, for power greater than 30W, 1W LED beads are mostly used, while for power less than 30W, low-power LED beads (such as 302030143528, etc.) are mostly used. It is recommended to use patch type low-power LEDs for heat dissipation and to improve the uniformity of light emission. Lamp beads can be arranged according to their shape. For example, if the shape is circular, the beads will be arranged in a circular shape. Conversely, if the shape is square, the beads will be arranged in a square shape.
There are two circles of LED beads on the circular printed circuit board, which uses 23 0.4W 5730 type LED beads with a total power of 18W. The rectangle in the middle is its constant current power supply, and the lower right corner of the square box is the photodiode of the remote control receiver, which receives the infrared control signal of the remote control brightness.
It should be noted that there are still a large number of low-priced LED ceiling lights that use low-power straw hat lights. However, due to the high thermal resistance of straw hat lights (450 ℃/W), it is difficult to dissipate heat, resulting in severe light decay and short lifespan.
Lampshade
The lampshade is usually made of PC board, and its performance is as follows:
(1) Transmittance: The highest transmittance of PC board can reach 89%, which is comparable to glass. UV coated boards will not produce yellowing, fogging, or poor light transmission when exposed to sunlight. After ten years, the loss of light transmission is only 6%, while the loss rate of PVC is as high as 15% -20%, and that of glass fiber is 12% -20%.
(2) Impact resistance: The impact strength of PC board is 250-300 times that of ordinary glass, 30 times that of acrylic board with the same thickness, and 2-20 times that of tempered glass. It can be dropped below two meters with a 3kg hammer without cracks and is known as "unbreakable glass" and "sound steel".
(3) UV protection: One side of the PC board is coated with a UV resistant layer, and the other side is treated with anti condensation, combining UV resistance, heat insulation, and anti drip functions. It can block UV rays from passing through and is suitable for protecting valuable artworks and exhibits from UV damage.
(4) Lightweight: With a specific gravity only half that of glass, it saves on transportation, unloading, installation, and supporting frame costs.
(5) Flame retardant: According to the national standard GB50222-95, PC boards are classified as Class B1 flame retardant. The ignition point of the PC board itself is 580 degrees Celsius, and it will self extinguish after leaving the fire. When burning, it will not produce toxic gases and will not promote the spread of fire.
(6) Flexibility: According to the design drawings, cold bending can be used on the construction site to install into arch, semi-circular roof, and window shapes. The minimum bending radius is 175 times the thickness of the board, and it can also be hot bent.
(7) Temperature adaptability: The PC board does not undergo cold brittleness at -100 ℃, does not soften at 135 ℃, and its mechanical properties do not show significant changes in harsh environments.
(8) Weather resistance: PC boards can maintain the stability of various physical indicators within the range of -40 ℃ to 120 ℃. After 4000 hours of artificial climate aging test, the yellowing degree was 2 and the decrease in transmittance was only 0.6%.
