The LED lens is closely associated with the LED to enhance the light use efficiency and luminous efficiency, and the optical system that can change the light field distribution of the LED using different lenses according to different effects. This article focuses on secondary concentrating lenses for high power LEDs.
a. Because silicone is resistant to high temperatures (and can also be reflowed), LED light-emitting devices are commonly packaged directly.
b. The general silicone lens is small in volume and has a diameter of 3-10mm.
a. Optical grade PMMA (polymethyl methacrylate, commonly known as: acrylic).
b. Plastic materials, advantages: high production efficiency (can be completed by injection molding, extrusion); high transmittance (93% penetration at 3mm thickness); disadvantages: temperature can not exceed 80° (heat distortion temperature 92 degrees) ).
a. Optical grade Polycarbonate (PC) polycarbonate.
b. Plastic materials, advantages: high production efficiency (can be completed by injection molding, extrusion); light transmittance is slightly lower (the penetration rate is about 89% at 3mm thickness); disadvantage: the temperature can not exceed 110° (heat distortion temperature 135) °).
Optical glass material, advantages: rich optical parameter characteristics (optional), high light transmittance (97% penetration at 3mm thickness), high temperature resistance, etc. Disadvantages: large volume, heavy weight, single shape, fragile, Mass production is difficult to achieve, production efficiency is low, and costs are high. The price of such production equipment is high and it is difficult to popularize in the short term. In addition, the disadvantages of glass compared to PMMA and PC materials are more fragile, and more research and exploration are needed. In the improved process that can be achieved, the non-fragile properties of the glass can only be improved by coating or tempering treatment, although after these treatments, the glass is treated. The transmittance of the lens will be reduced, but it will still be much larger than that of ordinary optical plastic lenses. Therefore, the prospect of glass lenses will be broader.