Fresnel lens has two effects:

One is the focusing effect, which is to refract (reflect) the pyroelectric infrared signal on the PIR.

The second is to divide the detection area into a number of bright areas and dark areas, so that moving objects entering the detection area can generate a modified pyroelectric infrared signal on the PIR in the form of temperature changes.

Lens mainly comes in three colors:

First, the primary color of polyethylene material, slightly transparent, good light transmittance, not easy to deform.

Second, white is mainly used to adapt the color of the shell.

Third, black is used to prevent strong light interference. The lens can also be combined with the appearance of the product to make the product more beautiful.

Coupling application of lens and sensor: