Fresnel lens - 8140

Fresnel lens developed by French light physicist FRESNEL .the lens are use the galvanization mold craft and PE (polyethylene) material suppress become.The lens (0.7mm thick) the surface engraved has recorded a circle from small to big, outward by shallowly to the deep concentric circle, from the section plane looked resembled the denticle.The round loop line many and the dense induction angle is big, the focal distance is far; The round loop line engraves deeply feeling which records to be supposed to be away from far, the focal distance is near.The infrared light more is depends on the concentric ring light to be more centralized strongly moreover.The identical line of several concentric rings compose a vertical induction area, between the concentric ring compose a level induction section.The vertical induction area are more the vertical induction angle to be bigger; The lens longer induction section more level induction angle is bigger.Sector quantity many is induced the human body to move the scope to be small, sector quantity is short is induced the human body to move the scope to have to be big.Between the different area concentric circle interlocks mutually, reduces between the sector the blind spot.Between the area and the area, between Duan and duan, between the sector forms the blind spot.Because the lens receive the infrared probe head field of view angle the restriction, vertical and the level induction angle is limited, the lens area is also limited.The lens from the outward appearance classification are: The long shape, the square shape, the circular, from the function classification are: Single area multistage, double area multistage, multi-area multistage.

The Fresnel lens function has two: One, the focusing action, soon hotly releases the infrared signal refraction (reflection) on PIR, the second function is divides into the search coverage in certain area pellucidae and the dark area, causes to enter the search coverage the motion object to be able to produce by the temperature change form on PIR changes releases the infrared signal hotly.