Patent ID: 6222688
Filing Date: 2001-04-24
Classification: G02B

Abstract:
A decentered optical system comprising:an entrance surface through which a light beam enters;a first reflecting surface reflecting the light beam;a second reflecting surface reflecting the light beam;a third reflecting surface reflecting the light beam; andan exit surface from which the light beam exits;wherein at least one of said entrance surface, said first, second and third reflecting surfaces and said exit surface has a rotationally asymmetric surface configuration having no plane of symmetry and giving a positive power to the light beam; andwherein at least one of an intersection between said entrance surface and an optical axis, an intersection between said first reflecting surface and the optical axis, an intersection between said second reflecting surface and the optical axis, an intersection between said third reflecting surface and the optical axis, and an intersection between said exit surface and the optical axis is not in a plane where the other intersections are present.