JP-7854822-B2 - Light intensity control devices and optical instruments

JP7854822B2JP 7854822 B2JP7854822 B2JP 7854822B2JP-7854822-B2

Inventors

山本健太
中脇慎也

Assignees

キヤノン電子株式会社

Dates

Publication Date: 20260507
Application Date: 20220314

Claims (4)

A light intensity adjustment device in which each of a plurality of light intensity adjustment vanes overlaps with other light intensity adjustment vanes to form a light-passing aperture, and the size of the light-passing aperture is changed by the rotation of the plurality of light intensity adjustment vanes, Each of the plurality of light intensity adjustment vanes has a first portion with a constant thickness and a second portion that is formed such that its thickness decreases from the first portion toward the edge portion that forms the edge of the light-passing aperture. A light intensity adjustment device characterized in that, in the minimum aperture state of the light intensity adjustment device, when the plurality of light intensity adjustment vanes overlap in the direction of light passage, the first portions of adjacent vanes overlap , and the overlapping area of the second portions of adjacent vanes is larger than the overlapping area of the first portions.
The first area EC is the overlapping area of the first parts, the second area EB is the overlapping area of the first part and the second part, and the third area EA is the overlapping area of the second parts. EC < EA < EB The light intensity adjustment device according to claim 1, characterized in that it satisfies the relationship.
The light intensity adjustment device according to claim 1 or 2, characterized in that the angle formed by both surfaces in the thickness direction of the second portion, or the angle formed by the tangents of said surfaces, is 1 degree or more and 4 degrees or less.
A light intensity control device according to any one of claims 1 to 3 , An optical device characterized by having an image sensor that captures light that has passed through the light intensity adjustment device.

Description

This invention relates to a light intensity adjustment device mounted on optical equipment such as imaging devices and interchangeable lenses. In optical devices such as imaging devices and interchangeable lenses, the shape of the aperture (diaphragm) formed as a light-passing aperture is preferably as close to a circle as possible. To form a nearly circular aperture, multiple aperture blades (light-controlling blades) of three or more are often used. Patent Document 1 discloses an iris diaphragm device that forms a nearly circular polygonal aperture opening by rotating a number of aperture blades using a drive ring that rotates around a fixed opening formed in a base member. Japanese Utility Model Publication No. 2-48928 An exploded perspective view of an aperture device according to Embodiment 1 of the present invention.Plan view and cross-sectional view of the aperture blades used in the aperture device of Embodiment 1.A view of the aperture blades of the aperture device of Embodiment 1 in the small aperture state, as seen from the optical axis direction.A perspective view showing the curvature of the aperture blades in the small aperture state of the aperture device of Embodiment 1.A cross-sectional view of an imaging device equipped with the aperture device of Embodiment 1.A schematic diagram of an imaging device equipped with the aperture device of Embodiment 1.Cross-sectional view of an imaging device equipped with a conventional aperture mechanism.A perspective view showing the curvature of the aperture blades in a conventional aperture device at a small aperture setting. The embodiments of the present invention will be described in detail below with reference to the drawings. <Embodiment 1> Figure 1 is a disassembled view of the aperture device 100, which is an embodiment 1 of the light intensity control device of the present invention. Figure 2 is a view of one of the aperture blades, which are used as light intensity control blades in the aperture device, showing the shape when viewed from the front and the cross-sectional shape along line A-A. In Figure 1, 1, 2, 3, 4, 5, 6, 7, 8, and 9 are aperture blades. This embodiment describes the use of nine aperture blades, but the present invention can be applied to aperture devices using three or more aperture blades (light intensity control blades). In the following description, aperture blades 1, 2, 3, 4, 5, 6, 7, 8, and 9 will be abbreviated as aperture blades 1 to 9, and each part of aperture blades 1 to 9 will be abbreviated as 1x to 9x. The aperture blades 1 to 9 are integrally molded parts formed in a thin plate shape from synthetic resin. As shown in Figure 2, each aperture blade 1 to 9 has a base portion on opposite sides, with first shaft portions 1c to 9c, which serve as the pivot axis, and second shaft portions 1d to 9d, which are driven shafts to which the driving force for rotation is input. The blade portions 1b to 9b are tapered from the base to the tip. Furthermore, the blade portions 1b to 9b have opening-side portions 1a to 9a, which will be explained in detail later. Furthermore, in Figure 1, 10 is a ring-shaped rotating member with an opening 10a formed in its center. In the following description, the direction perpendicular to the opening surface of this opening 10a and the openings (11a, 12a) formed in the members (11, 12) described later is referred to as the optical axis direction. The rotating member 10 has nine axial holes 10b to 10j formed in its circumferential direction, nine rib sections 10k divided in the circumferential direction, and a gear section 10l formed in a part of its circumferential direction. Element 11 is a ring-shaped cam member and also serves as the cover member of the throttling device in this embodiment. An opening 11a is formed in the center of the cam member 11. Furthermore, cam grooves 11b to 11j are formed at nine locations in the circumferential direction of the cam member 11. Additionally, a hole 11k is provided at one location in the circumferential direction of the cam member 11. Six claw portions 11l are formed at six locations in the circumferential direction of the outer circumference of the cam member 11, which engage with six recesses 12e formed at six locations on the outer circumference of the base plate 12. Reference numeral 12 denotes a base plate formed in a ring shape, with an opening 12a formed in its center. Furthermore, a motor mounting portion 12c having a hole 12b is provided at one location in the circumferential direction of the base plate 12. Element 13 is a stepping motor that drives the rotating member 10. A pinion gear 14 is mounted on the output shaft of the stepping motor 13 so as to rotate integrally with the output shaft. The stepping motor 13 is fixed to the motor mounting portion 12c of the base plate 12, and the pinion gear 14 passes through the hole 12b of the base plate 12 and meshes with the gear portion 10l of the rotating member 10. Alternatively, the stepping mo