Abstract: A wide angle lens system, in order from an object side to an image side, the wide angle lens system includes a first lens with negative refraction power, a second lens with positive refraction power, and an image plane. The wide angle lens system is satisfied with the following formulas: (1) 5<TTL/f<7; (2) ?1.9<f1/f<?1.0; (3) 1.0<f2/f<2.0, where TTL is a distance between an object side surface of the first lens and the image plane, f is a focal length of the wide angle lens system, f1 is a focal length of the first lens, f2 is a focal length of the second lens.

Abstract: A lens includes a light incident surface and a light output surface. The light incident surface includes a first region having points equidistant from the central point of a light emission surface of the light emitting element. The first region satisfies ?a??1??b, wherein ?1 is a first incident angle of any light emitting from the light emitting element. In a second region with 0°<?1??b+20°, the first incident angle of light having a minimum value of ?2/?1 is between ?a and ?b, and ?2/?1>0.9. In a third region with 0°<?1??b+10°, the first incident angle of light having a minimum value of ?3/?1 is between ?a and ?b, and ?3/?1>0.9. ?2 is a second incident angle of the light of ?1 when traveling in the lens, and ?3 is a third incident angle of the light of ?1 when emitting out of the lens.

Abstract: A lens includes a light incident surface and a light output surface. The light incident surface includes a first region having points equidistant from the central point of a light emission surface of the light emitting element. The first region satisfies ?a??1??b, wherein ?1 is a first incident angle of any light emitting from the light emitting element. In a second region with 0°<?1??b+20°, the first incident angle of light having a minimum value of ?2/?1 is between ?a and ?b , and ?2/?1>0.9 . In a third region with 0°<?1??b+10°, the first incident angle of light having a minimum value of ?3/?1 is between ?a and ?b, and ?3/?1>0.9. ?2 is a second incident angle of the light of ?1 when traveling in the lens, and ?3 is a third incident angle of the light of ?1 when emitting out of the lens.