High-power LED lamp bead lens classification

Time:2020-04-06 08:47:04 / Popularity: / Source:

First, material type of high power LED lamp bead lens

high-power LED lamp bead lens mould 

1. High power LED lamp bead silicone lens

a. Because silicone is resistant to high temperatures (and can also be reflowed), it is often used to package directly on LED chips.
b. General silicone lens is small in volume and has a diameter of 3-10 mm.

2. High power LED lamp bead 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. High power LED lamp bead PC lens

a. Optical grade Polycarbonate (PC).
b. Plastic materials. Advantages: high production efficiency (can be completed by injection molding, extrusion); light transmittance is slightly lower (penetration rate is about 89% at 3mm thickness). Disadvantage: temperature can not exceed 110° (heat deformation temperature 135 degree).

4. High power LED lamp bead glass lens

Optical glass material. Advantages: high light transmittance (97%), high temperature resistance, etc. Disadvantages: single shape, fragile, difficult to achieve mass production, low production efficiency, high cost. However, at present very few manufacturers in China have begun to develop glass molding processes, and use glass casting to produce glass lenses, which can produce lenses of various shapes and special surfaces.
In addition, moulding process, product consistency, high precision molding, and can greatly improve production efficiency, effectively reduce cost of glass lenses, coupled with high light transmittance, glass lens is bound to become an alternative to optical plastic high power LED lenses. However, current high prices of such production equipment are difficult to popularize in short term. In addition, disadvantages of glass compared to PMMA and PC materials are more fragile, more research and exploration are needed. In improved process that can be realized now, non-fragile properties of glass can only be improved by coating or tempering treatment. Although light transmittance of glass lens is reduced after these treatments, it will still be much larger than that of ordinary optical plastic lens. Therefore, prospect of glass lenses will be broader.

Second, application classification of high-power LED lamp bead lens

1. Primary lens

a. Primary lens is directly encapsulated (or bonded) on LED chip holder and integrated with LED.
b. LED chip (chip) theoretically emits 360 degrees, but in fact chip is fixed and packaged on the LED holder, so maximum illumination angle of chip is 180 degrees (there is also a small amount of residual light in the range of more than 180°), and chip also has some stray light, so that all light of chip can be effectively concentrated by one lens and different light-emitting angles such as 180°, 160°, 140°, 120°, 90°, 60°, etc. can be obtained. However, light-emitting efficiency of LEDs with different light-emitting angles is different (general rule is: the greater angle, the higher efficiency).
c. Primary lens is generally made of PMMA, PC, optical glass, silica gel and so on.
high-power LED lamp bead lens mould 

2. High power LED lamp bead secondary lens

a. Secondary lens and LED are two separate objects, but they are inseparable when applied.
b. Function of secondary lens is to converge illumination angle of LED light source again to any desired angle between 5° and 160°. Distribution of light field can be mainly divided into: circular, elliptical and rectangular.
c. Secondary lens materials are generally optical grade PMMA or PC; glass is currently only selected under special circumstances. However, with popularization and popularization of glass moulding process, secondary lens will usher in a material revolution, and optical glass will replace optical grade PMMA or PC.

Third, high-power LED lamp bead lens specification classification

1. Penetrating (convex lens)

a. When LED light passes through a curved surface of lens (two convex surfaces have two curved surfaces), light will refract and condense, angle will also change when distance between lens and LED is adjusted (angle is inversely proportional to distance), Optically designed lens spot will be very uniform, but due to lens diameter and lens mode limitations, light utilization rate of LED is not high and edge of spot has a relatively obvious yellow edge (reason for yellow edge is not repeated here);
b. Generally used in large angle (50° or more) concentrating, such as table lamps, bar lights and other indoor lighting;

2. Reflex type (tapered or cup type)

a. Design of lens is concentrating in front of concentrating light, and tapered surface can collect and reflect all side light, and overlapping of two kinds of light (same angle) can get the most perfect light utilization and beautiful spot effect;
b. It is also possible to make some changes on the surface of conical lens, which can be designed as a mirror, frosted, bead, striped, thread, convex, concave surface to obtain different spot effects.

3. Lens module

a. It is to complete a single multi-head lens by injection molding a plurality of single lenses. According to different requirements, it can be designed as a 3in1, 5in1 or even dozens of lens modules. It is also possible to combine two separate lenses through bracket.
b. This design effectively saves production costs, achieves consistent product quality, saves space in lighting mechanism, and is easier to achieve "high power" and other characteristics.

Fourth, design and moulding process of high-power LED lamp bead lens mould

1. First of all, depending on light source (high-power LED lamp bead), different brands of high-power LED lamp beads (such as CREE, Lumileds, Seoul, Osram, Everlight, Edison, Changsen source, etc.), its chip structure and packaging, light characteristics will be different, resulting in same lens with different specifications of brand LED will be difference; therefore targeted development (mainstream brand-oriented) is required to achieve actual demand;
2. Design and optical simulation using optical design software (such as Code V, ZEMAX, TracePro, ASAP, LighTools, etc.), mechanical modeling software (such as Pro/E, UG, SOLIDWORKS, etc.), continuously optimized to obtain corresponding optical lens.
3. LED lens itself is a precision optical component, so its precision for precision molding is extremely high, especially processing precision of optical surface of lens is 0.1 μm. Generally, processing of such high precision molding must have following equipment: ultra-precision processing machine (such as: PRECITECH NANOFORM 350), CNC integrated processing machine, precision grinding machine, precision milling machine, drilling machine, CNC precision spark machine, surface profiler, interferometer, etc.
4. The most precise part of precision molding lies in optical mold. First, special mold steel (such as: Swedish S136 mirror steel) must be heat treated to 55° to complete rough embryo. It is obtained by subjecting rough embryo to nickel plating treatment and then performing surface machining with an ultra-precision processing machine.
high-power LED lamp bead lens mould 

Fifth, material and production of high-power LED lamp bead lens

1. As an optical grade product, LED lenses have strict requirements on light transmission, thermal stability, density, refractive index uniformity, refractive index stability, water absorption, turbidity, and maximum long-term operating temperature. Therefore, material of lens must be selected according to actual situation. In principle, optical grade PMMA is chosen, and optical grade PCs can be selected if there are special requirements. At present, Japanese Mitsubishi PMMA material is the best (VH001 is a frequently selected grade), and Mitsubishi's branch in China, Nantong Liyang, will be can be second choose;
2. It must be equipped with a dust-free workshop of 10,000 or higher level. Operators must wear anti-static clothing such as anti-static clothing, finger-sets, and masks, and regularly inspect and clean workshop.
3. Professional optical injection molding machines such as Toshiba, Demag, Haitian, Zhenxiong must be used, and injection molding process must be strictly controlled to obtain qualified products.
4. Product inspection: no bubbles, no dents, no creases, no flow lines, no crescents, shape accuracy Rt<0.005, surface roughness Ra<0.0002.
5. Product must be packaged in anti-static, dust-proof PVC and must be completely sealed. Temperature and humidity must be strictly controlled. It is best not to store it for more than one year.

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