Optical apparatus
The invention relates to an optical apparatus allowing images in multiple directions to be simultaneously taken with simple construction using a prism optical system yet with high definitions even at wide angles of view. Specifically, the invention provides an optical apparatus using a prism optical system which has three optical surfaces: a first surface having transmission, a second surface having internal reflection plus transmission and a third surface having reflection and is formed of a medium having a refractive index of 1.3 or greater and in which light enters the medium through the first surface, is totally reflected at the second surface, and then reflected at the third surface 13 , and finally leaves the medium this time through the second surface. At least two prism optical systems ( 101, 102 ) are arranged side by side with respect to an imaging plane of a single imaging device ( 30 ) so that images in at least two directions are formed side by side on the imaging plane of the single imaging device ( 30 ), and at least one of three surfaces of each of said prism optical systems ( 101, 102 ) has a reflecting surface defined by a rotationally asymmetric plane.
1. An optical apparatus using a prism optical system which has three optical surfaces: from an object side thereof, a first surface having transmission, a second surface having internal reflection plus transmission and a third surface having reflection and is formed of a medium having a refractive index of 1.3or greater and in which light enters the medium through the first surface ( 11 ), is totally reflected at the second surface ( 12 ) and then reflected at the third surface ( 13 ), and finally leaves the medium this time through the second surface ( 12 ), characterized in that at least two said prism optical systems are arranged side by side with respect to an imaging plane of a single imaging device so that images in at least two directions are formed side by side on the imaging plane of the single imaging device, and at least one of three surfaces of each of said prism optical systems has a reflecting surface defined by a rotationally asymmetric plane.
2. An optical apparatus as recited in claim 1 , characterized in that two said prism optical systems are arranged side by side, and said two prism optical systems comprise prism optical systems that are of the same shape and positioned such that one of said prism optical systems is rotated 180° with respect to another and about axial chief rays directing toward an image plane to keep said axial chief rays parallel with one another.
3. An optical apparatus as recited in claim 2 , characterized in that said two prism optical systems are provided between them with a light block member for blocking off light from the adjacent prism optical systems.
4. An optical apparatus as recited in claim 2 or 3 , characterized by further including a hood that is located on an object side with respect to said prism optical systems and adapted to block off light rays that are incident on adjacent said prism optical systems and, once passing through one of said prism optical systems, enter another.
5. An optical apparatus as recited in claim 1 , characterized by being used as an onboard camera capable of simultaneously viewing both right and left directions.