A Method for Measuring and Identifying Fresnel Lens

Abstract

The invention relates to a method for measuring a Fresnel lens and a method for identifying a Fresnel lens. The method for identifying the quality of the Fresnel lens comprises the following steps that: a Fresnel lens is selected, the grating pitch d' of the Fresnel lens is initially measured with a magnifying lens; computer pattern design software is adopted to design equidistant concentric circle lines in black alternating with white, the grating D of the lines is slightly different from the d', the concentric circle lines in black alternating with white are printed on a special film througha special film distributing machine for printing; the printed film is tightly covered with the Fresnel lens, a user can see the concentric circle lines in black alternating with white presenting black and while concentric rings on the Fresnel lens owning to interference, and the emerging black and while concentric rings on the Fresnel lens are equidistant black and while concentric ring patterns;and the color saturation of the black ring patterns in the black and while concentric rings is identified, and if the color saturation is high, the quality of the Fresnel lens is good, and vice versa. The methods of the invention have the advantages of convenient and fast operation, high measuring accuracy and small error.

Description

technical field [0001] The invention belongs to the technical field of Fresnel lens measurement and identification, and in particular relates to a method for measuring and identifying Fresnel lenses. Background technique [0002] Fresnel lens, also known as threaded lens, was invented by French physicist Augustin Fresnel. It is generally a thin sheet made of polyolefin material. One side of the lens surface is smooth, and the other side is smooth. The concentric threads from small to large are engraved, and these threads are designed according to the requirements of relative sensitivity and receiving angle by using the interference of light. The production requirements of Fresnel lens are very high. A high-quality lens must have a smooth surface and clear texture. Better, although it is slightly worse than the ordinary convex lens made of glass material, but the cost is much lower than the ordinary convex lens, and it is often used in occasions that do not require high prec...

AI Technical Summary

Problems solved by technology

At present, there is no research on the precise measurement of Fresnel lens pitch and identification of Fresnel lens quality

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