Title:
PHASE DIFFERENCE DETECTOR
Document Type and Number:
Japanese Patent JPH01185606
Kind Code:
A
Abstract:
PURPOSE:To detect a phase difference over the entire focus surface by calculating the distance of an object point according to the output of a photodetecting element array and rotating separator lenses around the optical axis of a lens for primary image formation. CONSTITUTION:An image is formed on a liquid crystal shutter array 2 in an in-focus state by the lens 1 for primary image formation and then formed as two spots at a distance L on the light receiving element array 5 through separator lenses 41 and 42. The image distance between secondary formed images is longer and longer as the distance between the body point and lens 1 for primary image formation is shorter and shorter. The relation between the distance of the body point and image distance is predetermined according to the positions of respective shutters of a liquid crystal shutter array 2 and inputted to an arithmetic unit, and the couple of separator lenses 41 and 42 are rotated around the optical axis AX to calculate the distance in the direction of the body point from the output of the photodetecting element array 5 unless the body point is on the optical axis and even when the body point is in the in- focus, front-focus, or rear-focus state.
Inventors:
INADA TOSHIO
Application Number:
JP928288A
Publication Date:
July 25, 1989
Filing Date:
January 19, 1988
Export Citation:
Assignee:
RICOH KK
International Classes:
G03B13/36; G02B7/34; G03B3/00; (IPC1-7): G02B7/11; G03B3/00
Attorney, Agent or Firm:
Toru Kabayama (1 person outside)
Previous Patent: OPTICAL SEMICONDUCTOR MODULE
Next Patent: RAM DISK USING METHOD AND STORAGE MEDIUM RECORDING THE SAME
Next Patent: RAM DISK USING METHOD AND STORAGE MEDIUM RECORDING THE SAME