Patent ID: 8629896
Filing Date: 2014-01-14
Classification: G02B,H04N

Abstract:
1. A camera unit comprising: an imaging optical unit for forming images of a plurality of fields of view, the imaging optical unit having a plurality of free-curved surface prisms; a single imaging device for photoelectrically-converting the images formed by the imaging optical unit; a signal processing unit for processing the photoelectrically-converted signals from the imaging device and outputting image signals; a communication unit for performing communication with an external unit; and a control unit for controlling operation of the imaging device and the signal processing unit and transmitting the image signals output from the signal processing unit from the communication unit to the external unit, wherein the plurality of free-curved surface prisms have the same shape, each has three optical surfaces of a first surface having a transmission function for light from the outside, a second surface having a light internal reflection function and a light transmission function and a third surface having a light reflection function, among which optical surfaces having at least a reflection function have a lens function as well, where steps are provided on the both ends of the second surfaces of each of the free-curved surface prisms, and the imaging optical unit comprises a frame for fixedly-holding the plurality of free-curved surface prisms in parallel with each other, the frame having seat portions which are positioned and shaded to receive and accommodate the steps of the plurality of free-curved surface prisms; a holder for the frame itself being placed thereon, provided with a single imaging device for imaging light emitted from each of the free-curved surface prisms, as visual-field images, in parallel; and a cover body having window holes open corresponding to the fields of view, for storing the frame and the free-curved surface prisms inside thereof with the cover body being fixed into the holder; wherein the first surface of each of the free-curved surface prisms of the imaging optical unit has negative refractive power and the second surface and the third surface thereof have positive refractive power in the Y-Z plane; wherein the imaging optical unit is provided with two free-curved surface prisms of a first free-curved surface prism or a second free-curved surface prism with its first surface facing toward a field of view covering either of right side or left side, and a third free-curved surface prism disposed in parallel with the first free-curved surface prism or the second free-curved surface prism; and the third free-curved surface prism is provided with a front prism with its incidence surface facing toward a field of view covering front; wherein an L-shaped fixed stop is disposed on an incidence surface of the front prism of the imaging optical unit and a tall elliptical fixed stop is disposed between the front prism and the third free-curved surface prism such that the L-shaped fixed stop and the tall elliptical fixed stop function to restrict incident light rays; and the front prism is arranged at an upper position so that its incidence surface is at a higher position than the first surface of the third free-curved surface prism.