LED lens design and mold processing

Let's take you through how lenses are designed and manufactured

1, first depends on the light source (high power LED), different brands of high power LED(such as CREE, LUMILEDS, Seoul, Osram, Addison, etc.), its chip structure and packaging, light characteristics will be different, resulting in the same lens with different specifications of brand LED differences; Therefore, targeted development (oriented by mainstream brands) is required to achieve the actual needs;

2. Use optical design software (such as Tracepro, CodeV, Zemax, etc.) to design and simulate optical polishing, and obtain the corresponding optical aspheric surface;

3, LED lens itself is a precision optical accessories, so the precision of the mold is very high, especially the lens optical surface processing accuracy to reach 0.1μm, lens eccentricity to reach within 3μm. Generally, the processing of such high-precision molds must have the following equipment: ultra-precision machining machine (such as PRECITECHNANOFORM350), CNC integrated processing machine, surface grinding machine, milling machine, CNC discharge processing machine, surface profiler, etc.

4. The most precise part of the mold lies in the optical kernel. First, special steel is selected to complete the initial embryo, and then ultra-precision machining machine is used to process aspheric surface technology after nickel plating.

Advantages of LED lens：

1. Regardless of distance, lampshade (reflective cup) is not much different from lens. In terms of uniformity, lens will be better than reflective cup.

2, with small Angle LED lens, the effect is better than the lampshade, because to shoot far! Lampshade spotlight has passed through the lens (because the LED itself must have a lens) and then through a mask spotlight, this time will waste a lot of light, it is better to focus on the lens, and the lens luminous Angle is very good processing. If the space is available, use three 1W ones, rather than one 3W.

3, in contrast, the lampshade luminous uniform point range is large, but the luminosity is not good, the lens is the opposite.

4, LED penetration appears to be more upscale.

Deficiencies: light loss consideration

1.The luminous flux of the luminaries with bubble shell and lens should meet the light distribution required by the standard, and other factors such as the transmittance of the shell, lens and overflow light loss should also be considered. And the bubble lamp or for ordinary lighting with high power needs to use lens will be parallel beam diffusion processing, to meet the requirements of the standard. In order to make the optical effect more reasonable, the design of the lamp cover should be divided into rectangular small units, the purpose of doing so is to break the light wave surface, so that the product has a uniform appearance effect. In each small cell, an ellipsoid is used, because the surface has radians in both horizontal and vertical directions, allowing different diffusion effects to be achieved with different radii of curvature in both directions. Its fundamental purpose is to overcome the deficiency of traditional technology, rationally utilize the luminous flux, and realize the uniform and efficient distribution of light. In fact, the shell of the bubble lamp class is PC material (injection molding completed), spherical, pear-shaped, cylindrical bubble shell are non-small units, non-flat whole shell, light loss is large, light Angle is small.

2. Since the surface of a lens is a curved surface with radii of curvature in both horizontal and vertical directions, incident light can be diffused in both horizontal and vertical directions. Since the radii of curvature in the two directions are independent of each other, the two curvatures can be adjusted according to requirements, so that the light output can be diffused in different degrees in the two directions. Therefore, lenses made of bidirectional curvature surfaces can distribute light output more freely according to design requirements, use light flux more efficiently, and reduce unnecessary waste and glare. In addition, due to the use of smooth transition surface, the lamps have uniform transition light distribution and good appearance. Fully transparent PMMA lamps or lampshades create blinding or blinding strings of light in the center of the light source, but the brightness rapidly decreases outside the light source. Lighting in many social and work environments must eliminate this unpleasant atmosphere or minimize eye irritation.
3. The projection of each lens element on the body is rectangular, so that the elements can be tightly and neatly arranged. After the refraction of the lens element, the parallel incident beam forms a symmetrical diffusion in the horizontal direction and a downward deflected diffusion in the vertical direction. By adjusting the size of each unit in a set of lenses and the radius of curvature in two directions, the distribution of the emitted light flux in different solid angles is adjusted to achieve the light distribution required by the design.

Since the function of incident surface is to deflect light rays to form diffusion, the number of elements, the size of elements and the radius of curvature of each set of lenses can be changed according to the actual situation in product design. The actual situation is that the inner grain (for the small unit) on the lens of the high-power lens is done by the manufacturer, and the lens height, Angle and material are only considered when selecting it.

4. We choose to place the light source inside the focus of the lens. The farther away the light source is from the lens, the less the light flux collected by the lens, thus the lower the efficiency of the lens system. Where r- convex curvature radius, nL- refractive index of lens material, F - lens focal length In the case of selected lens material, the larger the focal length, the larger the curvature radius. Under the same lens aperture φ, the larger the curvature radius, the thinner the lens. The thicker the lens, the more obvious the aberration will be, thus affecting the use effect. Therefore, a lens with a larger focal length is chosen whenever possible. At the same time, the increase of focal length increases the size of the optical system, so the maximum focal length of the lens can not be blindly pursued. Because the lens thickness is not very large, Fresnel lens is not used to avoid increasing the complexity and cost of processing.