| 摘要 |
PROBLEM TO BE SOLVED: To provide a lens barrel realizing miniaturization, especially, the shortening of the length in an axial direction of a gear helicoid ring and realizing stable operation of the lens. SOLUTION: The lens barrel has a holder holding an imaging device; a fixed barrel having a female helicoid on its inner circumferential surface; a gear helicoid ring having a male helicoid screwed on the female helicoid of the fixed barrel and a spur gear formed on the thread ridge of the male helicoid on a gear helicoid projection formed on the outer circumference of a rear end; and a pinion meshed with the spur gear of the gear helicoid ring and driven to be rotated at a fixed position; and moves a lens group in the optical axis direction by the rotation of the gear helicoid ring. As for the gear helicoid projection of the gear helicoid ring, at least one of the rear ends of the thread ridge of the male helicoid having the spur gear is extended backward along the thread root of the helicoid and the thread root of the spur gear, and when the gear helicoid ring is located at a specified housing stop position, at least a part of the backward extension part advances into the holder. COPYRIGHT: (C)2004,JPO&NCIPI
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