CAM STRUCTURE FOR DRIVING ZOOM LENS

PURPOSE:To eliminate the trouble required to adjust focal length initially by coupling a driving member with a driven member through a cam and providing the shortest-focal-length part and longest-focal-length part of the cam with blind sectors. CONSTITUTION:The driving member 22 which is driven by r...

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Bibliographic Details
Main Authors HIRAI MASAYOSHI, YOSHIDA TOSHIO, KOBAYASHI KIYOTAKA, ONDA KAZUHIKO
Format Patent
LanguageEnglish
Published 25.04.1989
Subjects
OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
OPTICS
PHYSICS
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Summary:PURPOSE:To eliminate the trouble required to adjust focal length initially by coupling a driving member with a driven member through a cam and providing the shortest-focal-length part and longest-focal-length part of the cam with blind sectors. CONSTITUTION:The driving member 22 which is driven by receiving an external driving force and a moving lens barrel 4 which moves lens groups 1 and 2 in specific relation in the direction of the optical axis are coupled with each other by the cam 9 and the shortest-focal-length side end (W-end) part 9b and longest-focal-length side end (T-end) part 9c of this cam 9 are provided with the blind sectors wherein the moving lens barrel 4 does not move even during the operation of the driving member 22. Therefore, when the lens groups 1 and 2 are positioned at the W-end part 9b and T-end part 9c, the lens groups 1 and 2 do not move away from the W-end part 9b and T-end part 9c unless they are driven for longer than a specific time even if the external driving force for moving the lens groups 1 and 2 is applied. Consequently, the initial adjusting operation for the focal length is facilitated.
Bibliography:Application Number: JP19870264985