LED optic lens how to find the right one for the lighting fixtures

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How to find the right optic lens for LED lighting fixtures

How to find the right optic lens for LED lighting fixture

In the past 10years, with the top brand LED optic lens materials YIBAI has delivered world-class industrial lighting products & Roadway lighting fixtures all over the world.

Optic ens classification material type

  • Silicone lens. Because silica gel has high temperature resistance, it is often used to directly encapsulate the LED chip. Generally, the size of the silica gel LED optic lens is small, with a diameter of 3-10mm.
  • PMMA lens. Optical grade PMMA (polymethyl methacrylate, commonly known as acrylic). Plastic materials, advantages: high production efficiency (can be completed by injection molding or extrusion); high light transmittance (about 93% penetration when the thickness is 3mm); disadvantages: the temperature cannot exceed 80℃ (heat distortion temperature 92℃)
  • PC lens. Optical grade material Polycarbonate (referred to as PC). Advantages: high production efficiency (can be completed by injection molding and extrusion); light transmittance is slightly lower (the transmittance is about 89% when the thickness is 3mm); Disadvantages: the temperature cannot exceed 110℃ (heat distortion temperature 135℃ spend)
  • Optical glass materials, advantages: high light transmittance (97%), high-temperature resistance. Disadvantages: single shape, fragile, difficult to achieve mass production, low production efficiency, high cost, etc.

Applications classification

Primary lens

  • The primary lens is directly encapsulated (or glued) on the LED chip holder and integrated with the LEDs.
  • The LED chip (chip) theoretically emits 360 degrees, but in fact the chip can be fixed and packaged on the LED bracket, so the maximum light-emitting angle of the chip is 180 degrees (more than 180 degrees, there is a small amount of afterglow), and the chip There will also be some stray light, so that through a lens, all the light of the chip can be effectively collected and different light angles such as 180°, 160°, 140°, 120°, 90°, 60°, etc. can be obtained, but different The light-emitting angle of the LED has a certain difference in the light-emitting efficiency (the general rule is: the greater the angle, the higher the efficiency).
  • The primary lens generally uses PMMA, PC, optical glass, silica gel and other materials.

Secondary lens

  • The secondary LED optic lens and the LEDs are two independent objects, but they are indeed inseparable in application.
  • The function of the secondary lens is to converge the light-emitting angle of the LED light source to any desired angle between 5° and 160°. The distribution of the light field can be mainly divided into: circle, ellipse, and rectangle.
  • The secondary lens material generally uses optical grade PMMA or PC; currently, glass is only selected under special circumstances. However, with the promotion and popularization of glass molding technology, the secondary lens will usher in a material revolution, and optical glass will replace optical grade PMMA or PC.

Lens specification classification

Through type (convex lens)

  • When the LED light passes through a curved surface of the lens (double convex has 2 curved surfaces), the light will be refracted and concentrated, and when the distance between the lens and the LED is adjusted, the angle will also change (the angle is inversely proportional to the distance). The optically designed lens spot will be very uniform, but due to the limitation of the lens diameter and lens mode, the light utilization rate of the LED is not high and the edge of the spot has a relatively obvious yellow edge.
  • Generally used in large-angle (above 50°) spotlights, such as table lamps, bar lamps and other indoor lighting fixtures.

Catadioptric type (cone type or cup type)

  • The design of the LED optic lens uses a penetrating condensing light in the front, and the tapered surface can collect and reflect all the side light, and the overlap of these two kinds of light (the same angle) can get the most perfect light utilization with beautiful light spot effect.
  • Some changes can also be made on the surface of the conical lens, which can be designed into a mirror surface, a frosted surface, a bead surface, a striped surface, a threaded surface, convex or concave surface, etc. to obtain different spot effects.

Lens module

  • Complete a whole multi-lens lens through injection molding of multiple single lenses. According to different needs, it can be designed into a 3-in-1, 5-in-1 or even dozens of lens modules in one; two separate lenses can also be passed through the brackets are combined together.
  • This design effectively saves production costs, realizes the consistency of product quality, saves the space of the lamp mechanism, and it is easier to realize the characteristics of “high power”.

Lens design and mold processing

  • First of all depends on the light source (high-power LED lamp beads), different brands of high-power LED lamp beads (such as CREE, Lumileds, Seoul, Osram, Everlight, Edison, Changsenyuan, etc.), its chip structure and packaging methods, The light characteristics will be different, which will cause differences when the same lens is matched with different specifications and brand LEDs; therefore, targeted development (oriented by mainstream brands) is required to achieve the actual desired effect;
  • Use optical design software (such as Code V, ZEMAX, TracePro, ASAP, LighTools, etc.) and mechanical modeling software (such as: Pro/E, UG, SOLIDWORKS, etc.) for design and optical simulation, and continuously optimize to obtain the corresponding optical lens
  • The LED optic lens itself is a precision optical accessory, so it has extremely high requirements on the accuracy of the mold, especially the processing accuracy of the lens optical curved surface must reach 0.1μm. Generally, the following equipment is required for the processing of such high-precision molds: ultra-precision processing machine (such as PRECITECH NANOFORM 350), CNC integrated processing machine, precision grinder, precision milling machine, drilling machine, CNC precision spark machine, surface profiler, interferometer Wait.
  • The most precise part of the mold is the optical mold core. First, a special mold core steel (such as Swedish S136 mirror steel) must be heat treated to 55° to complete the rough embryo. After nickel plating on the rough embryo, use an ultra-precision processing machine. Obtained by surface processing.

Lens materials and production

  • As an optical-grade product, LED optic lens have strict requirements on light transmittance, thermal stability, density, refractive index uniformity, refractive index stability, water absorption, turbidity, and maximum long-term working temperature. Therefore, the material of the lens must be selected according to the actual situation. In principle, choose optical grade PMMA, if you have special requirements, you can choose optical grade PC. At present, the PMMA material of Mitsubishi is the best (VH001 is a frequently selected grade), while Nantong Liyang, the branch of Mitsubishi in China, will be slightly inferior;
  • It must be equipped with a dust-free workshop with a level of 10,000 or higher. The operators must wear anti-static clothing, finger cots, and masks, and other anti-static and dust-proof measures, and the workshop should be inspected and cleaned regularly.
  • It is necessary to have professional optical injection molding machines such as Toshiba, Demag, Haitian, Chen Hsong and other brands, and strictly control the injection molding process to obtain qualified products.
  • Product inspection: no bubbles, no dents, no sink marks, no flow lines, no crescents; shape accuracy Rt<0.005 surface roughness Ra<0.0002.
  • The product must be packaged in anti-static and dust-proof PVC, and must be completely sealed. The temperature and humidity must be strictly controlled for storage, and it is best not to store it for more than one year.

Yibai LED lighting is mainly focusing on designing high-performance industrial LED lights and public lighting fixtures. For any questions or need on led lighting, please feel free to contact us via info@yboptotech.com, YIBAI LED LIGHTING, high quality LED lights with a professional engineer team that will support you within 24 hours!

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