JP7204362B2 - Aperture device, lens device, and imaging device - Google Patents

Description

The present invention relates to an aperture device, a lens device, and an imaging device.

Conventionally, a plurality of diaphragm blades with a rotating shaft are arranged at equal angular intervals on the same circumference, and the diaphragm aperture is formed by overlapping the diaphragm blades by rotating the diaphragm blades around the rotating shaft of the diaphragm blades. is known. Such a diaphragm device generally has a structure in which two types of pins are provided on the diaphragm blades, and the movement of one pin relative to the other pin is guided by a cam groove. The shape of the diaphragm aperture affects the quality of the blur around the main subject in the image obtained by shooting, and the closer the shape is to a circle, the more beautiful the blur can be obtained. In general, the number of aperture blades is increased in order to approximate the shape of the aperture to a circular shape. In addition, particularly in TV broadcasting applications, it is required that the aperture blades cause little disturbance of the light beam over the entire range of opening and closing of the aperture blades. Further, in a diaphragm device in which a cam plate is driven by a motor, it is required to reduce power consumption by reducing the drive torque required for the motor. Patent Literature 1 discloses an aperture device that reduces frictional resistance to opening and closing of the aperture blades by a guide plate arranged between the aperture blades and a cam plate or a fixed plate.

Japanese Unexamined Patent Application Publication No. 2012-113102

In the aperture device disclosed in Patent Document 1, the friction between the aperture blades is not reduced. Therefore, as the opening diameter becomes smaller, the sliding resistance of the blades increases due to an increase in overlap of the blades, and a large driving torque is required for the motor.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an aperture device that is advantageous in, for example, reducing the frictional resistance between aperture blades.

A diaphragm device of the present invention includes a plurality of diaphragm blades each having a drive pin and a rotation center pin, a support member rotatably supporting the rotation center pin, a cam member having a cam that engages with the drive pin, a partition member that partitions two of the plurality of aperture blades ,
The partition member is formed with a hole through which the drive pin of one of the two aperture blades penetrates and a hole through which the rotation center pin of the other of the two aperture blades penetrates. do.

According to the present invention, for example, it is possible to provide an aperture device that is advantageous in reducing frictional resistance between aperture blades.

1 is a front view of a diaphragm device according to the present invention; FIG. 1 is an exploded perspective view of a diaphragm device according to the present invention; FIG. 1 is a vertical cross-sectional view of a diaphragm device according to the present invention; FIG. It is an enlarged view of a vertical cross-sectional view of a diaphragm device in the present invention. 4 is a front view of a cam plate in the present invention; FIG. 4 is a front view of aperture blades in the present invention; FIG. FIG. 4 is a front view of a diaphragm blade support cylinder according to the present invention; FIG. 4 is a diagram showing a blade driving range on a sheet member in the present invention;

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

A diaphragm device according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 8. FIG. FIG. 1 is a front view, FIG. 2 is an exploded perspective view, FIG. 3 is a longitudinal sectional view, and FIG.

The aperture device 1 determines the aperture diameter of a lens device (lens system) including a focus lens group, a zoom lens group, a relay lens group, etc. (not shown), and is an aperture driving unit that continuously changes the aperture shape. .

As shown in FIG. 2, the diaphragm device 1 includes a diaphragm blade support tube (blade support member) 2, a plurality of diaphragm blades 3a and 3b, a cam plate (cam member) 4, a presser fitting 5, a sheet member (partition member) 6. As shown in FIGS. 3 and 4, the plurality of aperture blades 3a and 3b and the sheet member 6 are sandwiched between the aperture blade support tube 2 and the cam plate 4. As shown in FIGS. The cam plate 4 rotates inside the inner diameter portion of the aperture blade support tube 2 around the central axis o, and movement in the direction of the central axis o relative to the aperture blade support tube 2 is controlled by a pressing metal fitting 5 positioned with respect to the inner diameter portion. Regulated. The pressing metal fitting 5 has a C-ring shape, and is inserted into the inner diameter portion of the aperture blade support cylinder 2 by deforming the opening of the C-ring portion so as to narrow it, and releasing the deformation to return it to its original shape. is fixed to the aperture blade support cylinder 2 with .

FIG. 5 shows a front view of the cam plate 4. As shown in FIG. The cam plate 4 has two types of cam grooves with different minimum diameters, six cam grooves 4a and three light shielding cam grooves 4b. FIG. 6 shows a front view of the aperture blades 3a and 3b. A rotation center pin 3c rotatably engaged with a pin hole 2a provided in the aperture blade support cylinder 2 and a cam groove 4a, 4b of the cam plate 4 are slidably engaged with the plurality of aperture blades 3a, 3b. The drive pin 3d which aligns is integrally constructed.

FIG. 7 shows a front view of the aperture blade support tube 2. As shown in FIG. The pin holes 2a of the aperture blade support cylinder 2 are provided on the same circumference, and the phase intervals around the center of the opening corresponding to the optical axis position of the respective hole positions are equal to each other, and the inner edges of the aperture blades 3a and 3b are equal to each other. The shape of the diaphragm opening formed by the overlap of the portions is substantially circular. With the above configuration, the driving pins 3d of the aperture blades 3a and 3b slide along the cam grooves 4a and 4b of the cam plate 4 to change the aperture shape. A feature of the cam grooves 4a and 4b is that the minimum diameter portions are arranged concentrically around the optical axis o. Here, the cam groove 4b has a groove shape with a smaller minimum diameter than the cam groove 4a, and is used when light is blocked by the aperture blade 3b. The cam grooves 4b are equally divided with respect to the pin holes 2a provided in the aperture blade support cylinder 2, and when the aperture blades 3b shield the optical path, the apertures are made smaller while having a triangular opening shape. to block the light. In this embodiment, the total number of cam grooves 4a and 4b is nine, and the number of cam grooves 4b used for light shielding is three. The number of grooves 4b may be increased or decreased.

FIG. 8 shows the trajectory of the diaphragm blade 3a driven on the sheet member 6. As shown in FIG. In the diaphragm device according to the present invention, of the nine diaphragm blades 3a and 3b, only one diaphragm blade 3b, which engages with the light shielding cam groove 4b, is partitioned by the sheet member 6, so that the remaining eight diaphragm blades are divided. The drive surface is divided into 3a and 3b in the optical axis direction. FIG. 8 shows a range (area A) in which the aperture blade 3a is driven from the position where the aperture shape is maximized to a position in which light is blocked, and a range (area A1) in which the tip of the aperture blade 3a is driven. The sheet member 6 includes an escape groove (escape portion) 6a for escaping a region through which the drive pin 3d of the aperture blade 3b divided in the optical axis direction penetrates, and rotation centers of the nine aperture blades 3a and 3b. It has an escape hole (escape portion) 6b through which the pin 3c passes. That is, the sheet member (partition member) separates two aperture blades out of a plurality of aperture blades, and forms an escape portion for escaping the drive pin 3d of one of the two aperture blades and the rotation center pin 3c of the other. It is The escape groove 6a is provided in a range that does not overlap with the region A1, and has a shape in which the aperture blades 3a do not hang over the escape groove 6a when the aperture shape of the diaphragm is changed. The escape hole 6b of the sheet member 6 is set to fit with the rotation center pins 3c at two or more positions of the aperture blades 3a and 3b, thereby suppressing the eccentricity with respect to the aperture blades 3a and 3b. Further, in the diaphragm device 1, the maximum aperture diameter is formed by the sheet member 6 instead of the diaphragm blades 3a and 3b, thereby suppressing unnecessary stray light due to the inner diameter of the diaphragm blades.

In this embodiment, only one sheet member 6 is constructed and the diaphragm blades 3a and 3b are divided into two in the optical axis direction, but this is not the only option. The blades 3a and 3b may be divided into a plurality in the optical axis direction. In this case, the shape of the aperture formed by the diaphragm blades can be kept substantially circular until the light is blocked, and a beautiful blur can be obtained until the light is blocked. The sheet member 6 may be used for dividing the aperture blades 3a and 3b in the optical axis direction, and may be made of a resin material, a metal material, a film, or the like, and may be as thick as the aperture blades 3a and 3b. .

A change in the diaphragm opening in the diaphragm device of the present embodiment will be described based on the above structure. When the cam plate 4 is rotated about the optical axis center o with respect to the aperture blade support cylinder 2, the driving pins 3d of the aperture blades 3a and 3b are guided by the cam grooves 4a and 4b, respectively. As a result, the diaphragm blades 3a and 3b rotate around the rotation center pin 3c, and the diaphragm blades 3a and 3b swing along the trajectory of the cam grooves 4a and 4b to change the aperture diameter.

Next, a description will be given of the case where the cam plate 4 is rotated in the direction in which the aperture diameter is changed from the maximum aperture diameter to the light shielding direction. When the cam plate 4 is rotated, the drive pin 3d of the diaphragm blade 3a is guided to the minimum diameter position of the cam groove 4a before the diaphragm blade 3b blocks light. When the cam plate 4 is further rotated from this state, the drive pin 3d of the aperture blade 3b is guided along the cam groove 4b to the minimum diameter position of the cam groove 4b. Since the cam groove 4a of the minimum diameter portion is provided centering on the optical axis o, the aperture blade 3a engaged with the cam groove 4a does not swing in conjunction with the rotation of the cam plate 4, and the cam groove is closed. Light is blocked by swinging only the aperture blade 3b that engages with 4b.

In this embodiment, the aperture blades 3a and 3b are opened and closed by rotating the cam plate 4, but the cam plate 4 may be fixed and the aperture blade support cylinder 2 may be rotated. In this case, the sheet member 6 rotates integrally with the aperture blade support cylinder 2 .

According to the diaphragm device of the present embodiment, by providing the sheet member 6 between the diaphragm blades 3a and 3b, the number of overlapping diaphragm blades 3a and 3b can be reduced, and the sliding resistance between the diaphragm blades can be suppressed. . In addition, by simply adding the sheet member 6 to the diaphragm device, malfunction due to sliding resistance between the diaphragm blades can be suppressed, and the diaphragm device can be provided which enables stable light amount adjustment with a simple structure.

Further, an imaging apparatus having a lens apparatus including the diaphragm apparatus of the above-described embodiment and an image sensor disposed on the image plane of the lens apparatus provides an imaging apparatus that can enjoy the effects of the diaphragm apparatus of the present invention. be able to.

Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist.

1: Diaphragm device 2: Diaphragm blade support cylinder (support member)
2a: Pin hole 3a: Aperture blade 3b: Aperture blade (for light shielding)
3c: rotation center pin 3d: drive pin 4: cam plate (cam member)
6: Sheet member (partition member)

Claims (8)

a plurality of aperture blades each having a drive pin and a rotation center pin;
a support member that rotatably supports the rotation center pin;
a cam member having a cam that engages the drive pin;
a partition member that partitions two of the plurality of aperture blades ,
The partition member is formed with a hole through which the drive pin of one of the two aperture blades penetrates and a hole through which the rotation center pin of the other of the two aperture blades penetrates. throttling device. a plurality of aperture blades each having a drive pin and a rotation center pin;
a support member that rotatably supports the rotation center pin;
a cam member having a cam that engages the drive pin;
a partition member that partitions two of the plurality of aperture blades;
has
A diaphragm device, wherein a maximum opening diameter is determined by an inner diameter of the partition member. The partition member is formed with a hole through which the drive pin of one of the two aperture blades penetrates and a hole through which the rotation center pin of the other of the two aperture blades penetrates. 3. A diaphragm device according to claim 2 . 4. A diaphragm device according to claim 1, wherein at least one of said plurality of diaphragm blades is provided between said partition member and said support member. 4. A diaphragm device according to claim 1 , wherein the hole through which said drive pin penetrates is formed so as not to overlap the trajectory of said other rotation about said rotation center pin. 3. The partition member is formed with at least two holes through which at least two rotation center pins of at least two of the plurality of aperture blades pass respectively . 6. The diaphragm device according to any one of 5. lens system and
A lens device according to any one of claims 1 to 6 for forming an aperture of said lens system. a lens device according to claim 7;
and an imaging device disposed on the image plane of the lens device.

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