Patent Number: 6,637,899

Title: Optical element and optical system having the same

Abstract: An optical element formed from a transparent optical material includes tworefraction surfaces, a first reflection surface group having a pluralityof internal reflection surfaces arrayed in a predetermined direction, asecond reflection surface group opposing the first reflection surfacegroup and having at least one internal reflection surface and two sidesurfaces opposing each other in parallel to the predetermined direction.Light incident from one of the refraction surfaces is alternatelyreflected by the internal reflection surfaces of the first reflectionsurface group and the internal reflection surface of the second reflectionsurface group and guided to the other refraction surface. The width of atleast one of the plurality of internal reflection surfaces of the firstreflection surface group and at least one internal reflection surface ofthe second reflection surface group in a direction in which the two sidesurfaces oppose each other is smaller than the distance between the twoside surfaces in the direction in which the side surfaces oppose eachother.

Inventors: Sunaga; Toshihiro (Kawasaki, JP), Hoshi; Hiroaki (Fujisawa, JP), Akiyama; Takeshi (Yokohama, JP)


International Classification: G02B 17/08 (20060101); G02B 005/10 (); G02B 017/00 ()

Expiration Date: 10/22015