LED lens are generally silicone lens. Because silicone has high temperature (can lead reflow), so it is commonly encapsulated directly on the LED chip. Generally, the volume of silicone lens is relatively smaller, and its diameter is 3-10mm. And generally the led lens is closely linked together with LED lights, it helps to enhance the light efficiency of LED lamps, and the lens can change the LED light field distribution of the optical system.
Advantages of LED Lens
1, Regardless of distance, the lampshade (reflective cup) has not many differences with the lens, and in terms of uniformity, the lens will be better than the reflector cup; 2, the LED lens with small angle will be better than the lampshade, because it can shoot far! Lampshade condenser has been through the lens (LED itself, there will be a lens) and then again through the second-time mask condenser, this will waste a lot of light, this is far good from concentrating on in the lens, and the lens of the light-emitting angle might be well dealt with! And by the way, if space permits, use three 1W LED lens, the effect would be much better than using a 3W LED! 3, under contrast, the lampshade light-emitting is uniform and has bigger point range, but the cast luminosity is bad, the lens is the opposite.
Classifications of LED Lens
Usually, the led lens manufacturer classify LED lens into several categories according to different materials.
1. Silicone lens: silicone has high temperature, so it is commonly used for direct package of LED devices. Generally, the volume of silicone lens is smaller and its diameter is 3-10mm.
2. PMMA lens: the optical grade PMMA (polymethyl methacrylate, commonly known as: acrylic). It is plastic materials, and its advantages are high efficiency (completed by injection molding, extrusion); high transmittance (93% penetration in 3 mm thickness); and the disadvantages are the temperature should not exceed 80 ° (heat distortion temperature is 92 degrees).
3. PC lens: polycarbonate optical grade material the Polycarbonate. It is plastic material and its advantages are high efficiency, the transmittance is slightly lower, the transmittance is about 89% in 3 mm thickness; and the disadvantages are the temperature must not exceed 110 ° (heat distortion temperature is 135 degrees).
4. Glass lens: it is optical glass material and the advantages are rich in optical parameters, a high transmittance (transmittance is 97% in 3 mm thickness), high temperature resistant; the disadvantages are bulky mass, the shape is single, and mass production is not easy to achieve, low production efficiency and high cost.
The article is come from:http://www.leddisplaylight.net/blog/?p=6