1.silica gel lens A. is usually packaged directly on the LED chip because of its high temperature resistance and reflow soldering. B. general silica gel lens is small in size and 3-10mm in diameter.
2.PMMA lens A. optical grade PMMA (polymethyl methacrylate, commonly known as acrylic). B. Plastic materials, advantages: high production efficiency (can be done by injection, extrusion); high transmittance (3mm thickness when the penetration rate is about 93%); defects: the temperature can not exceed 80 degrees (thermal deformation temperature 92 degrees).
3.PC lens A. optical grade Polycarbonate (PC) polycarbonate. B. plastic material, advantages: high production efficiency (can be done by injection, extrusion); light transmittance is slightly lower (the penetration rate of 3mm thickness is about 89%); defects: the temperature can not exceed 110 degrees (thermal deformation temperature 135 degrees).
4. glass lens optical glass material, advantages: high light transmittance (97%), high temperature resistance and other characteristics; shortcomings: single shape, fragile, batch production is not easy to achieve, low production efficiency, high cost. However, at present, few manufacturers have begun to develop glass molding technology, using mold casting and casting glass lens, can produce a variety of shape, special surface of the lens. In addition, mold production, good product consistency, high precision, and can greatly improve the production efficiency, effectively reduce the cost of glass lens, coupled with high transmittance, glass lens is bound to become a substitute for the optical plastic LED lens.