Patent ID: 6362921
Filing Date: 2002-03-26
Classification: G02B,H04N

Abstract:
An optical apparatus comprising:an optical element; a casing accommodating said optical element; said optical element comprising an entrance refractive surface, an exit refractive surface and a plurality of reflective surfaces provided between said entrance refractive surface and said exit refractive surface, a light flux entering an inside of said optical element at said entrance refractive surface, being reflected a plurality of times at said plurality of reflective surfaces and exiting from said exit refractive surface; wherein a protruded structure or a recessed structure formed in a circular shape or a cylindrical shape with a center thereof set to a reference axis of the entering light flux is provided adjacent to said entrance refractive surface; and wherein said casing has an engaging portion engaging with said protruded structure or said recessed structure, said optical element being turnable about the reference relative to said casing.