Patent ID: 7075735
Filing Date: 2006-07-11
Classification: G02B

Abstract:
1. A stereo imaging unit comprising a single image pickup device and a stereo imaging optical system capable of forming on said single image pickup device at least two parallactic images having mutual parallaxes, wherein said stereo imaging optical system comprises: a first entrance window and a second entrance window that have entrance surfaces located on a subject side and are juxtaposed in a left-and-right direction, a plurality of reflecting surfaces for guiding a light beam incident on said first entrance window to said single image pickup device, a plurality of reflecting surfaces for guiding a light beam incident on said second entrance window to said single image pickup device, a first negative lens group having negative refracting power on the light beam incident on said first entrance window and a first positive lens group that is positioned on an image side of said first negative lens group via a longest air space in a lens system and has positive refracting power, and a second negative lens group having negative refracting power on the light beam incident on said second entrance window and a second positive lens group that is positioned on an image side of said second negative lens group via a longest air space in the lens system and has positive refracting power, with satisfaction of conditions (1), (2), (3) and (4): where f N1 is a focal length of said first negative lens group, f N2 is a focal length of said second negative lens group, f P1 is a focal length of said first positive lens group, f P2 is a focal length of said second positive lens group, f 1T is a focal length of the stereo imaging optical system including said first negative lens group, and f 2T is a focal length of the stereo imaging optical system including said second negative lens group.