Fresnel lens, also known as screw lens, is mostly a sheet made of polyolefin material by injection pressure, and also made of glass. One side of the lens surface is smooth, and the other side is burned with concentric circles from small to large. Its texture is designed according to the interference and interference of light, as well as the requirements of relative sensitivity and receiving angle. The requirement of lens is very high. A high-quality lens must have a smooth surface and clear texture. Its thickness varies with the application, mostly about 1mm. Its characteristics are large area, thin thickness and long detection distance.
Fresnel lens is equivalent to the convex lens of infrared and visible light in many times, with good effect, but its cost is much lower than that of ordinary convex lens. Most of them are used in situations where the accuracy is not very high, such as slide projector, film magnifier, infrared detector, etc.
Using ordinary convex lens, the edges and corners will be dimmed and blurred. This is because the refraction of light only occurs at the interface of the medium, and the convex lens is thick, and the straight-line part of the light in the glass will make the light attenuate. If we can remove the part of straight-line propagation and only keep the refracted surface, we can save a lot of materials and achieve the same focusing effect at the same time. Fresnel lens is based on this principle. Fresnel lens looks like a piece of glass with numerous concentric circles (i.e. Fresnel belt), but it can achieve the effect of convex lens. If the projection light source is parallel light, after converging and projecting, it can keep the brightness of all parts of the image consistent.
We are a professional manufacturer of aspherical mirrors. At present, we can provide square and circular aspherical mirrors with the size of 5mm-2000mm. The light transmittance is more than 93%, the thickness is 2-5mm, and the focus factor is more than 500 times. Focal length, facula, ring distance, etc. can be customized according to user requirements.
Small size aspheric mirror can be used for infrared detection, infrared induction, radar, etc.
Medium sized aspheric mirror can be used for outdoor advertising lighting, indoor lighting, stage lighting, traffic lights, optical projection amplification (imaging), etc.
The large-scale solar photovoltaic (CPV) concentrating aspherical mirror can focus the sunlight directly on the solar panel or solar cell. After concentrating, the lighting capacity is 30% higher than that of the general silicon wafer, which greatly enhances the lighting effect.
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