Patent ID: 7944635
Filing Date: 2011-05-17
Classification: G02B

Abstract:
1. A lens barrel comprising: a shooting optical system contained in a barrel, the shooting optical system being operable to lead a subject image to an image sensor, the shooting optical system; a back focus adjustment lens group constituting a part of the shooting optical system and operable to be fixed immovably after the position of the back focus adjustment lens group is adjusted in an optical axis direction of the shooting optical system; and a back focus adjustment mechanism operable to adjust the position of the back focus adjustment lens group in the optical axis direction of the back focus adjustment lens group, wherein the back focus adjustment mechanism includes a barrel engagement member possessing a plurality of engagement surfaces arranged in the barrel in a circumferential direction centering on the optical axis, each of the plurality of engagement surfaces possessing a different height in a direction parallel with the optical axis, and a lens engagement member arranged in a lens holding frame which holds the back focus adjustment lens group, the lens engagement member being operable to be selectively engaged with the engagement surfaces, wherein the back focus adjustment lens group is adjusted in position in the optical axis direction by changing the engagement surfaces with which the lens engagement member is engaged, and wherein the adjoining engagement surfaces are formed to possess one of increasing difference in height and decreasing difference in height along the circumferential direction.