| 摘要 |
PROBLEM TO BE SOLVED: To improve the position accuracy and the optical performance of a lens group while suppressing the manufacturing cost of a lens barrel having at least tow lens groups to be relatively moved. SOLUTION: The lens barrel having a first and second lens groups to be relatively moved, is provided with a first lens retaining ring which has the first lens group, a rotating ring which is rotatably supported by the first lens retaining ring, and is rotationally driven, a second lens retaining ring which is located between the inside surface of the rotating ring and the outer surface of the first lens retaining ring, and has the second lens group, a bottomed direct advance guide groove parallel to an optical axis which his formed on one of the outer surface of the first lens retaining ring and the inside surface of the second lens retaining ring, and a direct advance guide projection which movably fits into the bottomed direct advance guide groove and is formed on the other of the outer surface of the first lens retaining ring and the inside surface of the second lens retaining ring, and a cam projection and a follower projection which are formed in one side and the other side of the inside surface of the rotation ring and the outer surface of the second lens retaining ring respectively, and which engage with each other. The first lens retaining ring, the second lens retaining ring, and the rotating ring are made into entire ring bodies which do not have a pass-through part in a radial direction, respectively.
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