JPS6134505Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a light-shielding diaphragm mechanism that controls a light beam in an optical system, and particularly relates to a center light-shielding diaphragm mechanism that expands the light-shielding portion outward from the center of the light beam. .

[Prior art]

Conventionally, a light-shielding diaphragm that controls the light flux in an optical system uses a plurality of light-shielding vanes arranged on the circumference.
It was configured to move from the outer periphery of the light beam toward the center. However, depending on the application, for example, if strong light concentrates near the optical axis of the optical system and interferes with measurement, it may be necessary to start blocking the light from the center of the beam and gradually expand the blocking area toward the outer periphery. However, until now, no light-shielding diaphragm mechanism has been proposed that meets this demand.

[Purpose of invention]

The present invention was developed in view of the above circumstances, and its purpose is to provide a center shading diaphragm mechanism that can expand the shading portion of the luminous flux from the center toward the outer periphery and reduce it from the periphery toward the center. It is on offer.

[Summary of the idea]

This invention covers both end faces of a cylindrical outer frame with an upper lid and a lower lid that have openings in the center, and the center portions of each are rotated by multiple rotating shafts installed concentrically in the lower lid. A plurality of transparent vanes are provided that are pivotably supported, have a light shielding part on the center side, and long holes on the outer circumferential side, and multiple moving shafts that are slidably fitted into these long holes. A blade rotary disk on which is planted is provided, and as the blade rotary disk rotates, the plurality of light shielding parts are moved between the center and the outer periphery of the outer frame, and the light is shielded by these light shielding parts. The intended purpose is achieved by enlarging and reducing the area.

[Example of idea]

Hereinafter, one embodiment of the central light-shielding diaphragm mechanism according to the present invention will be described with reference to the drawings.

1 and 2 are a longitudinal sectional view and an exploded perspective view, respectively, showing an embodiment of the present invention. A lower lid 2 with an opening 2a formed in the center is fixed to the bottom of the cylindrical outer frame 1 with a plurality of screws 3.
In this lower cover 2, a necessary number, for example, 12 blade plate rotation center shafts 4 are installed concentrically toward the inside of the outer frame 1. Holes 5a through which the rotating shafts 4 pass are provided on the lower lid 2 at positions aligned with the rotating shafts 4.
A transparent disk 5 is fixedly formed and has a small circular light shielding part 5b in the center. On this transparent disk 5, six transparent small movable vanes 6 are provided in a radially laminated manner. One end of each of these transparent small movable vanes 6 is formed into a substantially disk shape, and a small circular light shielding portion 6b is provided at the center of this disk portion.
is provided, and a hole 6a that fits with the rotating shaft 4 is formed in a portion protruding from this disc portion,
Furthermore, an elongated hole 6c is formed near one end of the protruding portion on the opposite side to the disk portion with respect to the hole 6a. These transparent small movable vanes 6 are rotatably supported on every other rotating shaft 4 through holes 6a formed therein. Twelve transparent large-movement vanes 7 formed in almost the same shape as these transparent small-movement vanes 6 are stacked radially on top of these transparent large-movement vanes 6. Similarly to the small movable blade plate 6, holes 7a, light shielding portions 7b, and holes 7c are formed in each of the blades 7. These transparent large-movement vanes 7 are each as described above.
They are rotatably supported on 12 rotating shafts 4, one at a time, through holes 7a. Above these transparent large-movement blade plates 7, a transparent disk 8 is provided which is provided with a hole 8a and a light-shielding portion 8b like the transparent disk 5, and these holes 8a each have a hole 8a and a light-shielding portion 8b. 4 is passing through. Furthermore, an annular blade rotary disk 9 is provided on the transparent disk 8, and the blade rotary disk 9 is fitted with elongated holes 6c and 7c formed in the blade plates 6 and 7, respectively. Twelve moving shafts 10 are installed concentrically downward, and a portion thereof is provided with a handle 9a for operation. It protrudes outward through the formed notch 1a. An upper lid 11 of the outer frame 1 is provided on the blade rotary disk 9, and an opening 11a is formed in the center of the upper lid 11 at a position aligned with the opening 2a of the lower lid 2. This opening 11a
There are 12 holes 11 around the rotating shaft 4 for locking the rotating shaft 4.
b, and after assembly, the rotating shaft 4 is attached to the upper lid 11.
and a lower cover 2, and the upper cover 11 is further fixed to the upper surface of the outer frame 1 by screws 12. Note that the shapes of the long holes 6c and 7c formed in the two blade plates 6 and 7, respectively, are similar to the shapes of the light shielding portion 6b when the blade rotary disk 9 is rotated.
and 7b are formed so that the amount of movement in the radial direction of the blade plate 7 is larger than that of the blade plate 6.

The operation of this embodiment configured as described above will be explained below with reference to FIGS. 3 and 4. When the blade rotary disk 9 is rotated clockwise by the handle 9a from the position shown in FIG. 3 to the position shown in FIG.
and 7a, rotates around the rotating shaft 4,
Long holes 6c formed in each of the blade plates 6 and 7
and 7c, the light shielding parts 6b and 7b move from the center toward the outer periphery while being guided by the moving shaft 10. At this time, since the large movable vane plate 7 is configured to have a larger movement amount than the small movable vane plate 6, the width of the light shielding part 6b occupies the inner side, and the width of the light shielding part 7b occupies the outer side. , light shielding part 6
By appropriately determining the sizes of b and 7b, the light shielding portions are always overlapped with each other to form an integrated light shielding portion. Therefore, if the blade rotary disk 8 is rotated clockwise, the light-shielding portion will expand from the center toward the outer periphery, and if it is rotated counterclockwise, the light-shielding portion will conversely contract from the outer periphery toward the center.

In this embodiment, a case has been described in which there are 12 rotating shafts 4, 6 small moving vanes 6, and 12 large moving vanes 7, but these numbers are limited to the numbers shown in this embodiment. However, the number may be determined as appropriate depending on the area of the light-shielding portion.

[Effect of idea]

As described above, according to the present invention, two sets of movable vanes are arranged radially, and by moving the light-shielding portions formed at the centers of these, the light-shielding portion is enlarged and contracted in two stages. Therefore, the light shielding portion of the light beam can be expanded from the center toward the outer periphery and reduced from the outer periphery toward the center using a simple mechanism.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing an embodiment of the central light-shielding diaphragm mechanism according to the present invention, FIG. 2 is an exploded perspective view of FIG. 1, and FIGS. 3 and 4 are operations according to an embodiment of the present invention. FIG. 1... Outer frame, 2... Lower cover, 4... Rotating shaft, 6,
7...Transparent wing plate, 6b, 7b...Light shielding part, 6
c, 7c...long hole, 9...blade rotary disk, 10...
Movement axis, 11...Top lid.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A cylindrical outer frame, an upper cover and a lower cover that respectively cover both end surfaces of the outer frame and have an opening in the center, and are planted concentrically on the lower cover. multiple rotating shafts, and a plurality of transparent blade plates that are rotatably supported approximately in the center by these rotating shafts, and each has a light shielding part on the center side and a long hole on the outer circumferential side. and a blade rotary disk in which a plurality of moving shafts are implanted and are slidably fitted into these long holes, and when the blade rotary disk rotates, the plurality of light shielding A central light-shielding diaphragm mechanism, characterized in that the center light-shielding diaphragm mechanism is configured to move the light-shielding parts between the center and the outer periphery of the outer frame to enlarge or reduce the light-shielding area by these light-shielding parts. (2) The central light-shielding diaphragm mechanism according to claim 1, wherein the plurality of transparent vanes are comprised of two sets, one for large movement and one for small movement.