Focus detecting device
AssigneeCanon Kabushiki Kaisha
InventorsTakeshi Koyama, Keiji Ohtaka
Life of this patent
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Abstract
A focus detecting device having a field lens disposed near the predetermined imaging plane of an objective and a secondary imaging optical system disposed rearwardly of the field lens, whereby a pair of object images based on light beams passing through different portions of the pupil of the objective are formed and the respective object images are detected by photoelectric conversion element rows disposed rearwardly of the secondary imaging optical system to thereby discriminate the focus state of the objective from the amount of relative deviation of the object images is characterized in that a refracting portion for refracting the light beam in the direction of arrangement of the photoelectric conversion elements is provided in the secondary imaging optical system.
Claims10
A device for detecting the state of focus adjustment of an objective, comprising:
- a field lens disposed in proximity to a prospective imaging plane of said objective;
- a plural-image forming optical system for forming a plurality of object images of varying relative positional relation from a light beam having passed through the objective, said plural-image forming optical system comprising a plurality of lenses each generating one of said object images;
- a sensor for producing a signal relating to the positional relation between said plurality of object images to discriminate the state of focus adjustment and for receiving the light beam forming said plurality of object images;
- and
- a refractor for refracting the light beam forming said plurality of object images only in the scanning direction of said sensor, said refractor being disposed apart from said field lens.
A device for detecting the state of focus adjustment of an objective, comprising:
- a field lens disposed on or near the predetermined imaging plane of the objective;
- a pair of imaging single lenses disposed rearwardly of said field lens and forming object images of varying relative positional relation;
- and
- a plurality of photosensors for producing a signal relating to the positional relation between the object images to discriminate the state of focus adjustment and for receiving a light pattern relating to said object images;
- one end of each of said imaging single lenses being spherical and the other end thereof being an inclined plane which refracts light in the direction of the arrangement of said plurality of photosensors.
Dependencies are inferred from the claim text.