The Basic Concept of The Lens
The lens is made according to the law of light refraction. A lens is an optical component made of a transparent substance such as glass, crystal, or others. The lens is a refractor whose refractive surface is two spherical surfaces (part of the spherical surface), or a spherical surface (part of the spherical surface) and a flat transparent body. It has a real image and a virtual image. Lenses can generally be divided into two broad categories: concave lens and convex lens. The central part is thicker than the edge part, which is called a convex lens while the central part is thinner than the edge part.
LED lenses are generally silicone lenses because silicone is resistant to high temperatures and can also be re-flowed, so it is usually packaged directly on LED chips. The general silicone lens is relatively small in volume, 3-10mm in diameter, and the LED lens is generally closely associated with the LED, which can help to improve the light-emitting efficiency of the LED and the optical system that changes the light field distribution of the LED.
The high-power LED lens or reflector is mainly used for collecting and guiding light of high-power LED cold light source products. The high-power LED lens designs the light distribution curve according to the angle of the different LEDs rather than the set aspherical optical lens, and increases the optical reflection to reduce the light loss and improve the light efficiency.
About the LED lens, hope the following explanation help you understand the difference on each material of LED lens and the advantages of LED lens.
I. The material classification of LED lens
1. Silicone lens
1) Because silicone is resistant to high temperatures (and can also be reflowed), it is usually packaged directly on the LED chip.
2) The general silicone lens is relatively small in volume and has a diameter of 3-10 mm.
1) Optical grade PMMA (polymethyl methacrylate, commonly known as: acrylic)
2) Plastic materials, which have the advantages of production efficiency (can be completed by injection molding, extrusion) and high transmittance (about 93% penetration at 3mm thickness), but also the temperature can not exceed 80 °C (heat distortion temperature 92 ° C )Shortcomings.
1) Optical grade Polycarbonate (PC) polycarbonate
2) Plastic materials, which have the advantages of production efficiency (can be completed by injection molding, extrusion) and high transmittance (about 89% penetration at 3mm thickness), but also the temperature cannot exceed 110 °C (heat distortion temperature 135 °C) )
4. Glass lens
Optical glass material, which has the advantages of high light transmittance (97% penetration at 3mm thickness) and high temperature resistance, but its disadvantage is that it is heavy in volume, single in shape, fragile, difficult to achieve mass production, and low production efficiency, high cost, etc.
II. The advantage of using LED lens
1. Regardless of the distance, the lampshade (reflector cup) is not much different from the lens. In terms of uniformity, the lens is superior to the reflector.
2. The effect of using a small angle LED lens is better than the lampshade because the lampshade has been condensed through the lens (and the LED itself must have a lens), and then concentrated by a reticle, making the uniform range of the illuminating point larger and wasting a lot of light. But with the LED lens, both the range and the angle of illumination of the lens can be well handled.