Model:2915 Fresnel lens is equivalent to convex lens of infrared and visible light in many cases. The effect is better, but the cost is much lower than convex lens. It is mostly used in occasions where the accuracy requirement is not very high, such as slide projectors, film magnifiers, infrared detectors, etc. Fresnel lens has two functions: one is focusing, i.e. refracting (reflecting) pyroinfrared signal on PIR, the other is dividing the detection area into several bright and dark areas, so that moving objects entering the detection area can produce pyroinfrared signal on PIR in the form of temperature change. .
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