Title:
METHOD OF AUTOMATICALLY POSITIONING LENS AND CAMERA EXECUTING SAME
Document Type and Number:
Japanese Patent JPS54158226
Kind Code:
A
Abstract:
An automatic camera focusing mechanism comprises a first electronic register for storing a number representative of the actual distance of the camera from the object (determined using bounced ultrasonic energy), a second electronic register for storing a number representative of the actual setting of the lens (determined using a grey code disc and grey-to-binary converter), a magnitude comparator which is responsive to a difference in register contents to operate a lens driving motor, and means for inhibiting the motor when the register contents are equal. In a cine camera, the content of the first electronic register varies at a rate dependent on the rate of actual distance determination, and the content of the second electronic register varies at a rate dependent on the rate of change of lens position. A reduction in lens hunting and a smoother change in focusing are effected by passing signals from the comparator to first and second shift registers and operating the motor, after a predetermined number of signals, in dependence on which register has the majority of signals.
Inventors:
EDOUIN KARUMAN SHIENKU
Application Number:
JP5080679A
Publication Date:
December 13, 1979
Filing Date:
April 24, 1979
Export Citation:
Assignee:
POLAROID CORP
International Classes:
G02B7/09; G02B7/28; G02B7/40; G03B13/36; (IPC1-7): G02B7/11; G03B3/00
Domestic Patent References:
| JPS52153433A | 1977-12-20 |