| 摘要 |
PURPOSE:To obtain a focus detector whose measurable distance range on the close side is extended by using an optical wedge, which is made of optical materials having an electrically variable refractive index and functions as a prism, to obtain the same effect that a prism is inserted to a parallel flat plates are used. CONSTITUTION:Distances up to objects 1a and 1b are detected based on the principle of trigonometry. For the purpose of detecting them, a range finding optical system 10 including optical wedges 2a1 and 2b2 whose refractive indexes are electrically changed, a refractive index control means 5 which controls refractive indexes of optical wedges 2a1 and 2b2, and a signal output means which outputs an electric signal related to the object distance in accordance with the object light led to the range finding optical system 10 are provided. A distance data output means 6 is provided which outputs object distance data based on the refractive indexes of optical wedges 2a1 and 2b2 and the electric signal. Thus, the measurable distance range of the focus detector is quickly extended without using mechanism members, and a range finder is miniaturized. |
