Focusing position detection apparatus Patent #: 4373791
ApplicationNo. 06/537026 filed on 09/29/1983
US Classes:396/104, Reliability of focus/distance signal250/201.8, Based on image shift250/204Adjusting optical system to balance brightness in plural paths
ExaminersPrimary: Perkey, William B.
Attorney, Agent or Firm
International ClassG02B 7/34 (20060101)
Foreign Application Priority Data1982-10-04 JP
AbstractAn apparatus for detecting a focus condition of an imaging lens of a still camera by detecting a lateral shift of two images formed on a light receiving element array by means of light fluxes transmitted through different sections of the exit pupil of the imaging lens divided by a stripe mask is disclosed. The variation of outputs from light receiving elements of the array due to an image height is corrected electrically by means of a correction circuit including first and second triangular wave generating circuits for generating first and second triangular waves having negative and positive inclinations, a clock pulse generator for producing clock pulses, a signal selection circuit for selecting alternately the first and second triangular waves in synchronism with the clock pulses to produce a correction signal, and a multiplying circuit for multiplying the outputs from the light receiving elements with the correction signal to provide a corrected signal from which the lateral shift can be detected accurately.