Light shielding unit and lens barrel equipped with the same

1 . A light shielding unit, comprising:

a first frame having a substantially annular main body and a first opening that is provided to a center portion of the main body and configured to allow light to pass through along an optical axis direction;

a second frame having a substantially annular main body and a second opening that is provided to the center portion of the main body and configured to allow light to pass through along the optical axis direction;

a plurality of movable blades that are disposed between the first frame and the second frame, that form a third opening through which the light that has passed through the first opening passes, configured to adjust an amount of light passing through by varying a size of the third opening by opening and closing operations;

a drive ring that is disposed between the first frame and the second frame and configured to be rotationally driven when the plurality of movable blades are opened and closed;

a drive source configured to rotationally drive the drive ring around an optical axis; and

a plurality of rotation shafts that are configured to serve as the center of rotation of the plurality of movable blades,

wherein the second frame further has first protrusions that protrude in a direction of the movable blades along the optical axis direction, and is configured to restrict a movement of the plurality of movable blades in the optical axis direction, and

wherein the movable blade has a cam groove,

the drive ring has a cam pin configured to engage the cam groove and move, and

the first protrusions are provided near the cam groove in which the cam pin for opening and closing the movable blade is inserted.

2 . The light shielding unit according to claim 1 ,

wherein the first protrusion is formed between the first frame and the second frame, and protrudes toward a storage space in which the movable blades are housed in a state in which the third opening is open.

3 . The light shielding unit according to claim 1 ,

wherein a plurality of the first protrusions are provided along a radial direction of a circle centered on the optical axis.

4 . A lens barrel, comprising:

the light shielding unit according to claim 1 ; and

a plurality of lens groups configured to guide a light incident on the light shielding unit in a desired direction.

5 . The lens barrel according to claim 4 ,

wherein the light shielding unit is an aperture unit configured to adjust an amount of the light that passes through the plurality of lens groups.

6 . The light shielding unit according to claim 1 ,

wherein the second frame has a recess into which a tip of the cam pin is inserted, and

the first protruding portion is disposed adjacent to the recess.

7 . The light shielding unit according to claim 6 ,

wherein the first protruding portion includes an inner diameter side protruding portion disposed adjacent to the recess in a radial direction centered on the optical axis, and

an outer diameter side protruding portion disposed on the opposite side in the radial direction centered on the optical axis with the recess interposed therebetween.

8 . A light shielding unit, comprising:

a first frame having a substantially annular main body and a first opening that is provided to a center portion of the main body and configured to allow light to pass through along an optical axis direction;

a second frame having a substantially annular main body and a second opening that is provided to the center portion of the main body and configured to allow light to pass through along the optical axis direction;

a plurality of movable blades that are disposed between the first frame and the second frame, that form a third opening through which the light that has passed through the first opening passes, and configured to adjust an amount of light passing through by varying a size of the third opening by opening and closing operations, and having a cam groove;

a drive ring that is disposed between the first frame and the second frame and configured to be rotationally driven when the plurality of movable blades are opened and closed; and

a drive source configured to rotationally drive the drive ring around an optical axis,

wherein the first frame further has a first outer shape portion that conforms to substantially parallel to the cam grove in a state in which the third opening is reduced to its smallest size by a rotation of the movable blades when the drive ring is rotationally driven by the drive source.

9 . The light shielding unit according to claim 8 ,

wherein the second frame further has a second convex portion that conforms to the external shape on the outside in the radial direction of a circle centered on the optical axis of the movable blades in a state in which the third opening is reduced to its smallest size by the rotation of the movable blades when the drive ring is rotationally driven by the drive source.

10 . The light shielding unit according to claim 8 ,

wherein the first outer shape portion is formed so that a part thereof protrudes outward in a radial direction from an outer peripheral portion of the substantially circular outer shape of the main body portion centered on the optical axis.

11 . The light shielding unit according to claim 8 ,

wherein the first outer shape portion is formed so that a part thereof is recessed inward in a radial direction from an outer peripheral portion of a substantially circular outer shape of the main body portion centered on the optical axis.

12 . The light shielding unit according to claim 8 ,

wherein the first outer shape portion has a first radial protruding portion formed so that a part thereof protrudes outward in a radial direction from an outer peripheral portion of a substantially circular outer shape of the main body portion centered on the optical axis, and a first radial recessed portion formed so that a part thereof is recessed inward in the radial direction from an outer peripheral portion of a substantially circular outer shape of the main body portion centered on the optical axis.

13 . The light shielding unit according to claim 8 ,

wherein the first outer shape portion is a convex portion.

14 . A light shielding unit, comprising:

a first frame having a substantially annular main body and a first opening that is provided to a center portion of the main body and configured to allow light to pass through along an optical axis direction;

a second frame having a substantially annular main body and a second opening that is provided to the center portion of the main body and configured to allow light to pass through along the optical axis direction;

a plurality of movable blades that are disposed between the first frame and the second frame, that form a third opening through which the light that has passed through the first opening passes, and configured to adjust an amount of light passing through by varying a size of the third opening by opening and closing operations;

a drive ring that is disposed between the first frame and the second frame and configured to be rotationally driven when the plurality of movable blades are opened and closed;

a drive source configured to rotationally drive the drive ring around an optical axis; and

a plurality of rotation shafts configured to serve as a center of rotation of the plurality of movable blades,

wherein the movable blades each have a second width portion in which a width is less than in a first width portion of a first end, and a third width portion in which the width is greater than in the second width portion, going from a first end side where the rotation shaft is provided toward a second end side that expands out toward a side of the third opening in a closed state, and

at least a part of the first width portion or at least a part of the third width portion maintain an overlapping state in the optical axis direction with the adjacent movable blade while the third opening changes its size, and

the second width portion does not maintain an overlapping state in the optical axis direction with the adjacent movable blade in at least one state while the third opening changes its size.

15 . The light shielding unit according to claim 14 ,

wherein, in a state in which the plurality of movable blades have rotated and the third opening has been reduced to its minimum, the third width portion is in a state of overlapping the adjacent movable blade, and an order in which the plurality of movable blades are disposed is maintained.

16 . The light shielding unit according to claim 14 ,

wherein the movable blades further have a fourth width portion in which the width is less than in the third width portion, going from the first end side where the rotation shaft is provided toward the second end side that expands out toward the third opening side in a closed state.

17 . The light shielding unit according to claim 14 ,

wherein the second width portion is disposed closer to a substantially radial inner side centered on the optical axis than the cam pin for rotationally driving the adjacent movable blade, in at least one state while the third opening changes its size.

18 . The light shielding unit according to claim 17 ,

wherein In the fully open state of the third opening, an outer diameter side outer shape of the movable blade centered on the optical axis, as viewed from the optical axis direction, is such that the second width portion has a shape that is relatively recessed with respect to the first width portion and the third width portion, and is smoothly connected by a continuous curve or straight line.