Flare-cut member, lens device, and optical device

1. A flare-cut member contained in an inner-lens barrel, the inner-lens barrel being rotatably housed inside an outer lens-barrel and having a common axis with the outer lens-barrel, the flare-cut member comprising:

a light shield surface that shields a light flux incident on periphery of a lens; and

an aperture permanently formed in the light shield surface to have a fixed shape and through which the light flux incident on a lens passes,

wherein the shape of the aperture is a polygonal shape having at least five sides and which is rotationally symmetric and point symmetric, and

wherein the flare-cut member is configured to enable rotational adjustments by being rotatable with the inner lens barrel so that a light shielding performed by the flare-cut member is maintained upon rotation of the flare-cut member with the inner lens barrel.

2. The flare-cut member according to claim 1 , wherein

the shape of the aperture is such that rotational symmetry exists at a plurality of angles.

3. The flare-cut member according to claim 1 , wherein

the shape of the aperture is a hexagonal shape.

4. The flare-cut member according to claim 1 , wherein

the shape of the aperture is an octagonal shape.

5. The flare-cut member according to claim 1 , wherein

the polygonal shape of the aperture is formed by a plurality of first sides and a plurality of second sides arranged in an alternating manner, wherein a distance from an aperture center of the aperture to each of the plurality of first sides has a first value and a distance from an aperture center of the aperture to each of the plurality of second sides has a second value, and wherein the first value is greater than the second value.

6. A lens device of a magnifying optical system comprising:

an outer lens-barrel;

an inner lens-barrel housed rotatably with respect to the outer lens-barrel inside the outer lens-barrel and having a common axis with the outer lens-barrel;

a plurality of rotational symmetrical lenses arranged on a coaxial optical axis inside the inner lens-barrel; and

a flare-cut member arranged on a light flux incident side of one lens of the plurality of lenses,

wherein the flare-cut member includes a light shield surface that shields a light flux incident on periphery of the one lens and an aperture permanently formed in the light shield surface to have a fixed shape and through which the light flux incident on the lenses passes,

wherein the shape of the aperture is a polygonal shape having at least five sides and which is rotationally symmetric and point symmetric, and

wherein the flare-cut member is configured to enable rotational adjustments by being rotatable with the inner lens barrel so that a light shielding performed by the flare-cut member is maintained upon rotation of the flare-cut member with the inner lens barrel.

7. An optical device comprising:

a plurality of lens devices of a magnifying optical system are arranged on an optical axis common to the plurality of lens devices, and the optical axis and a straight line connecting an object center and an image center are different,

wherein one of the plurality of coaxial lens devices includes:

an outer lens-barrel;

an inner lens-barrel housed rotatably with respect to the outer lens-barrel inside the outer lens-barrel and having a common axis with the outer lens-barrel;

a plurality of rotational symmetrical lenses arranged on a coaxial optical axis inside the inner lens-barrel; and

a flare-cut member arranged on a light flux incident side of one lens of the plurality of lenses,

the flare-cut member includes a light shield surface that shields a light flux incident on periphery of the one lens and an aperture permanently formed in the light shield surface to have a fixed shape and through which the light flux incident on the lens passes,

the shape of the aperture is a polygonal shape having at least five sides and which is rotationally symmetric and point symmetric, and

wherein the flare-cut member is configured to enable rotational adjustments by being rotatable with the inner lens barrel so that a light shielding performed by the flare-cut member is maintained upon rotation of the flare-cut member with the inner lens barrel.

8. The lens device according to claim 6 , wherein

the shape of the aperture is such that rotational symmetry exists at a plurality of angles.

9. The lens device according to claim 6 , wherein

the shape of the aperture is a hexagonal shape.

10. The lens device according to claim 6 , wherein

the shape of the aperture is an octagonal shape.

11. The lens device according to claim 6 , wherein

the polygonal shape of the aperture is formed by a plurality of first sides and a plurality of second sides arranged in an alternating manner, wherein a distance from an aperture center of the aperture to each of the plurality of first sides has a first value and a distance from an aperture center of the aperture to each of the plurality of second sides has a second value, and wherein the first value is greater than the second value.

12. The optical device according to claim 7 , wherein

the shape of the aperture is such that rotational symmetry exists at a plurality of angles.

13. The optical device according to claim 7 , wherein

the shape of the aperture is a hexagonal shape.

14. The optical device according to claim 7 , wherein

the shape of the aperture is an octagonal shape.

15. The optical device according to claim 7 , wherein

the polygonal shape of the aperture is formed by a plurality of first sides and a plurality of second sides arranged in an alternating manner, wherein a distance from an aperture center of the aperture to each of the plurality of first sides has a first value and a distance from an aperture center of the aperture to each of the plurality of second sides has a second value, and wherein the first value is greater than the second value.