Basic lens concept The lens is made according to the law of refraction of light. A lens is an optical component made of a transparent substance such as glass, crystal, or the like. 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) of a flat transparent body. It has a real image and a virtual image. Lenses can generally be divided into two broad categories: convex lenses and concave lenses. The central part is thicker than the edge part, which is called a convex lens, which has three kinds of convex, convex, convex and concave; the central part is thinner than the edge part, which is called concave lens, flat concave, convex and concave. LED lenses are generally silicone lenses, because silicone is resistant to high temperatures (and can also be reflowed), so it is usually packaged directly on the LED chip . Generally, silicone lenses are small in size and have a diameter of 3-10 mm. And the LED lens is generally closely associated with the LED, which helps to improve the light extraction efficiency of the LED, and the optical system that the lens changes the light field distribution of the LED. The LED lens is an optical system that is closely associated with the LED and contributes to improving the light extraction efficiency of the LED and changing the light field distribution of the LED. The high-power LED lens/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, and increases the optical reflection to reduce the light loss and improve the light efficiency (and the set aspherical optical lens). The following focuses on the secondary concentrating high power LED lens of PMMA material. a). Classification by material 1. Silicone lens a. Because silicone is resistant to high temperatures (and can also be reflow soldered), it is usually packaged directly on the LED chip. b. The general silicone lens is small in volume 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 completed by injection molding, extrusion); high transmittance (93% penetration at 3mm thickness); disadvantages: temperature can not exceed 80° (heat distortion temperature 92 degrees) ). 3.PC lens a. Optical grade Polycarbonate (referred to as 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) degree). 4. Glass lens USB Adapter, USB to Type C Adapter, USB C Female to USB A Male Adapter, USB Connector USB Adapter, USB to Type C Adapter, USB C Female to USB A Male Adapter, USB Connector Ningbo HanCheng(HC) Electronic Co.,Ltd , https://www.hcwires.com