JP2023143598A - Light quantity adjustment device and imaging device - Google Patents

Abstract

To provide a light quantity adjustment device that can be easily downsized.SOLUTION: A light quantity adjustment device comprises: a base member having a fixed opening that light passes through; a plurality of light-shielding blades that are arranged in the circumferential direction of the fixed opening and form a variable opening that light passes through; a drive ring that includes a plurality of axes rotating in the circumferential direction of the fixed opening to the base member and engaging with cam holes of the plurality of light-shielding blades, respectively, and that rotates the plurality of light-shielding blades so as to change the size of the variable opening by transmitting drive power to the light-shielding blades; and a drive source that drives the drive ring. The light-shielding blades have a first protrusion on the outer circumference on the side that is opposite the inner circumference that faces the fixed opening, a first recess, and a second protrusion, with the axis that pivots an adjacent light-shielding blade entering the first recess when the area of the variable opening is maximum, the first and second protrusions overlapping an adjacent light-shielding blade when the area of the variable opening is minimum.SELECTED DRAWING: Figure 9

Description

The present invention relates to a light amount adjusting device mounted on an optical device such as an imaging device or an interchangeable lens. The present invention also relates to an imaging device including a light amount adjustment device.

It is preferable that the shape of the diaphragm aperture as a light passing aperture formed in a light amount adjustment device (diaphragm unit) installed in an optical device such as an imaging device or an interchangeable lens be as close to a circle as possible, and a diaphragm aperture that is close to a circle is formed. In order to do this, three or more aperture blades (light amount adjustment blades) are often used.

Patent Document 1 discloses an iris diaphragm unit that forms a nearly circular polygonal diaphragm aperture by rotating a large number of diaphragm blades using a drive ring that is rotatable around a fixed aperture formed in a base member. Disclosed.

JP2017-058680A

In the aperture blade described in Patent Document 1, cam holes are usually formed by press working. In this method, since the cam holes are formed in the blades, there are problems in that the unit tends to be large and tends to interfere with adjacent blades.

The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a light amount adjustment device that can be easily miniaturized.

A light amount adjustment device according to the present invention includes a base member having a fixed aperture through which light passes, a plurality of light shielding blades arranged annularly in the circumferential direction of the fixed aperture and forming a variable aperture through which light passes, and the base member. The variable opening is provided with a plurality of shafts that rotate in the circumferential direction of the fixed opening with respect to the member and engage with each of the cam holes of the plurality of light shielding blades, and transmits a driving force to the light shielding blades. a drive ring that rotates the plurality of light-shielding blades so as to change the size of the light-shielding blade, and a drive source that drives the drive ring, and the light-shielding blade has an inner peripheral portion facing the fixed opening and a driving source that drives the drive ring. The shaft has a first convex portion, a first concave portion, and a second convex portion on the outer peripheral portion of the opposite side, and rotates the adjacent light shielding blade when the area of the variable opening is maximum. enters the first concave portion and the area of the variable opening is at a minimum, the first convex portion and the second convex portion overlap with the adjacent light shielding blade.

According to the present invention, it is possible to easily downsize a light amount adjusting device in which a plurality of light amount adjusting blades are provided with cam holes.

FIG. 1 is a plan view of an aperture unit according to a first embodiment of the present invention. FIG. 2 is a rear view of the aperture unit according to the first embodiment of the present invention. FIG. 1 is a perspective view of an aperture unit according to a first embodiment of the present invention. FIG. 2 is a perspective view of the aperture unit according to the first embodiment of the present invention in a small aperture state. FIG. 1 is a sectional view of an aperture unit according to a first embodiment of the present invention. FIG. 1 is an exploded perspective view of an aperture unit according to a first embodiment of the present invention. FIG. 3 is an explanatory diagram of the operation of the diaphragm unit according to the first embodiment of the present invention. FIG. 3 is a plan view of blades of the aperture unit according to the first embodiment of the present invention. FIG. 3 is a plan view of blades of the aperture unit according to the first embodiment of the present invention. FIG. 7 is a plan view of an aperture unit according to a second embodiment of the present invention. FIG. 3 is a rear view of an aperture unit according to a second embodiment of the present invention. FIG. 3 is a perspective view of an aperture unit according to a second embodiment of the present invention. FIG. 7 is a perspective view of an aperture unit according to a second embodiment of the present invention in a small aperture state. FIG. 3 is a sectional view of an aperture unit according to a second embodiment of the present invention. FIG. 3 is an exploded perspective view of an aperture unit according to a second embodiment of the present invention. FIG. 7 is an explanatory diagram of the operation of the aperture unit according to the second embodiment of the present invention. FIG. 7 is a plan view of blades of an aperture unit according to a second embodiment of the present invention. FIG. 7 is a plan view of blades of an aperture unit according to a second embodiment of the present invention. A schematic diagram of an imaging device equipped with an aperture unit.

Embodiments of the present invention will be described in detail below with reference to the drawings.

<First embodiment>
FIG. 1 is a plan view of an aperture unit 100, which is a first embodiment of a light amount adjustment device of the present invention. FIG. 2 shows a rear view of the aperture unit 100, and FIG. 3 shows a perspective view of the aperture unit 100.

FIG. 4 is a perspective view of the aperture unit 100 in a small aperture state. FIG. 5 is a cross-sectional view of the aperture unit 100 at a position where the motor, which is the drive section 5, is included.

FIG. 6 is an exploded perspective view of the aperture unit 100, in which a base member (ground plate) 4, a drive ring 7, a plurality of aperture blades 1 (shading blades), and a cover member 9 are stacked in this order in the thrust direction.

In FIG. 6, a base member 4 serving as the base of the diaphragm unit 100 has an opening (fixed opening) 4a through which light passes, corresponding to the optical path of the lens centered on the optical axis 50. On the outside of the opening 4a, an engaging pin 4c that engages with the fitting hole 1a (rotation center) of the 11 aperture blades 1 constituting the aperture blade group 10, which will be described later, is provided at an angle of 32.7° on the circumference. They are placed in 11 locations at regular intervals. The fitting hole 1a of the aperture blade 1 fits into the engagement pin 4c, and the aperture blade 1 rotates around the engagement pin 4c. The base member 4 is generally made by molding a resin. A drive unit 5 using a drive source such as a stepping motor or a galvanometer is attached to the base member 4, and a pinion gear 6 is attached to the rotating shaft of the drive unit 5.

The drive ring 7 that drives the aperture blade 1 is formed with an opening 7a, an outer diameter engaging portion 7b, and 11 locations at 32.7° intervals on the circumference, and engages with the cam hole 1b of the aperture blade 1. It has a drive pin 7c. The drive ring 7 is generally made by molding a resin. The outer diameter engaging portion 7b of the drive ring 7 is rotatably guided around the optical axis 50 by the inner peripheral guide surface 4b of the base member 4.

The plurality of aperture blades 1 constituting the aperture blade group 10 are arranged in a ring shape in the circumferential direction of the opening 4a, forming a variable aperture through which light passes. The drive pin 7c of the drive ring 7 is slidably engaged with the cam hole 1b of the aperture blade 1 in the aperture blade group 10. The cam hole 1b is guided by the drive pin 7c as the drive ring 7 rotates around the optical axis 50, and the aperture blade 1 is driven to open and close. The 11 aperture blades 1 are driven in a direction in which the aperture diameter is narrowed down by rotating the drive ring 7 in the direction of arrow A in FIG. 6, and the drive ring 7 is rotated in the opposite direction to arrow A. As a result, the opening diameter is driven in the direction of increasing.

A gear portion, which is a driven portion 7d, is formed in the drive ring 7. The driven part 7d meshes with the pinion gear 6 via intermediate gears 8a and 8b, and the rotational force (driving force) generated in the drive part 5 is transmitted from the pinion gear 6 to the driven part 7d, causing the drive ring 7 to rotate. be moved.

The aperture blade 1 is made, for example, by pressing a PET sheet material or the like. Further, it is desirable that the aperture blades be subjected to light shielding treatment, antireflection treatment, sliding treatment, etc.

A cover member 9 having an opening 9a formed in the center is disposed on the opposite side of the base member 4 across the aperture blade group 10. The cover member 9 is fixed to the base member 4 by having an engaging portion 9b formed on the outer circumferential portion thereof being engaged with a retaining portion 4d of the base member 4 due to its elasticity. Furthermore, eleven holes 9c formed on the circumference of the cover member 9 at intervals of 32.7° cover and overlap the tips of the engagement pins 4c of the base member 4, and press the aperture blade group 10 and the drive ring 7. In the space formed by the base member 4 and the cover member 9, the drive ring 7 and the aperture blade group 10 are driven.

FIG. 7 is an explanatory diagram of the operation of the aperture unit 100. FIG. 7A shows a state in which the aperture blades 1 are most retracted from the opening 4a of the base member 4. FIG. 7(b) shows a state in which the apertures formed by the plurality of aperture blades 1 coincide with the apertures 4a of the base member 4. 7(c) shows an intermediate aperture state, FIG. 7(d) shows a small aperture state, and FIG. 7(e) shows a minimum aperture state.

While the driving unit 5 is driven and the aperture blades 1 are in the minimum aperture state, the states shown in FIGS. 7(a) to 7(e) are changed. In this embodiment, eleven aperture blades 1 are used, but if a large number of aperture blades are used, the shape of the aperture aperture can be improved. In this embodiment, the cam hole 1b of the aperture blade 1 is formed at the rear end portion on the opposite side to the direction from the fitting hole 1a toward the tip side. As the number of aperture blades 1 increases, the arrangement of the cam holes 1b like this makes it easier to move the aperture blades 1.

FIG. 8 is a plan view of the aperture blade 1 alone. The aperture blade 1 includes a first convex portion 1c, a concave portion 1d, and a second convex portion 1e on the outer circumferential portion on the opposite side from the inner circumferential portion facing the opening 4a of the base member 4.

FIG. 9 is a plan view showing two extracted aperture blades 1 of the aperture unit 100 and their positions relative to the opening 4a of the base member 4. FIG. 9(a) shows the open state (state where the area of the variable aperture is maximum), and FIG. 9(b) shows the minimum aperture state. In the case of FIG. 9(a), the drive pin 7c, which is the shaft for rotating the adjacent aperture blades 1, enters the recess 1d on the outer periphery of the aperture blade 1, and in the case of FIG. 1c and the second convex portion 1e overlap with the adjacent aperture blades 1, it is possible to effectively utilize space and downsize the aperture unit. At this time, the first recess 1d has a portion outside the opening 4a that does not overlap with the adjacent aperture blades 1, making it easier to downsize the aperture unit.

As described above, in the first embodiment, the recess 1d is formed in the outer peripheral portion of the aperture blade 1, into which the drive pin 7c of the adjacent aperture blade 1 enters when the aperture opening is open. Thereby, interference between the aperture blades 1 and the drive pin 7c can be avoided, and the aperture unit 100 can be made smaller.

<Second embodiment>
Hereinafter, a second embodiment of the present invention will be described in detail with reference to the drawings. The main difference from the first embodiment described above is that the number of blades is changed from 11 to 13.

FIG. 10 is a plan view of an aperture unit 200 that is a second embodiment of the light amount adjustment device of the present invention. FIG. 11 shows a rear view of the aperture unit 200, and FIG. 12 shows a perspective view of the aperture unit 200.

FIG. 13 is a perspective view of the aperture unit 200 in a small aperture state. FIG. 14 is a cross-sectional view of the diaphragm unit 200 at a position where the motor, which is the drive section 205, is included.

FIG. 15 is an exploded perspective view of the aperture unit 200, in which a base member (ground plate) 204, a drive ring 207, a plurality of aperture blades 201 (shading blades), and a cover member 209 are stacked in this order in the thrust direction.

In FIG. 15, a base member 204 serving as the base of the diaphragm unit 200 has an opening 204a through which light passes, corresponding to the optical path of the lens centered on the optical axis 250. On the outside of the opening 204a, there are engagement pins 204c arranged at 13 locations at 27.7° intervals on the circumference, which engage with fitting holes 201a of 13 aperture blades 201 constituting a group of diaphragm blades 210, which will be described later. It is located in The fitting hole 201a of the aperture blade 201 fits into the engagement pin 204c, and the aperture blade 201 rotates around the engagement pin 204c. The base member 204 is generally made by molding resin. A drive unit 205 using, for example, a stepping motor or a galvanometer is attached to the base member 204, and a pinion gear 206 is attached to the rotation shaft of the drive unit 205.

The drive ring 207 that drives the aperture blade 201 is formed at 13 locations at 27.7° intervals on the circumference, including an opening 207a and an outer diameter engaging portion 207b, and engages with the cam hole 201b of the aperture blade 201. It has a drive pin 207c. The drive ring 207 is generally made by molding resin. The outer diameter engaging portion 207b of the drive ring 207 is rotatably guided around the optical axis 250 by the inner peripheral guide surface 204b of the base member 204.

The plurality of aperture blades 201 constituting the aperture blade group 210 are arranged annularly in the circumferential direction of the opening 204a, forming a variable aperture through which light passes. The drive pin 20c of the drive ring 207 is slidably engaged with the cam hole 201b of the aperture blade 201 in the aperture blade group 210. The cam hole 201b is guided by the drive pin 207c as the drive ring 207 rotates around the optical axis 250, and the aperture blade 201 is driven to open and close. The 13 aperture blades 201 are driven in a direction in which the aperture diameter is narrowed down by rotating the drive ring 207 in the direction of arrow A in FIG. 15, and the drive ring 207 is rotated in the opposite direction to arrow A. As a result, the opening diameter is driven in the direction of increasing.

A gear portion, which is a driven portion 207d, is formed in the drive ring 207. The driven portion 207d meshes with the pinion gear 206 via intermediate gears 208a and 208b, and the rotational force generated by the drive portion 205 is transmitted from the pinion gear 206 to the driven portion 207d, causing the drive ring 207 to rotate.

The aperture blades 201 are made, for example, by pressing a PET sheet material or the like. Further, it is desirable that the aperture blades be subjected to light shielding treatment, antireflection treatment, sliding treatment, etc.

A cover member 209 having an opening 209a formed in the center is arranged on the opposite side of the base member 204 with the aperture blade group 210 in between. The cover member 209 is fixed to the base member 204 by having an engaging portion 209b formed on the outer periphery thereof being engaged with a locking portion 204d of the base member 204 due to its elasticity. Further, thirteen holes 209c formed at 27.7° intervals on the circumference of the cover member 209 cover and overlap the tips of the engagement pins 204c of the base member 204, and press the aperture blade group 210 and the drive ring 207. In the space formed by the base member 204 and the cover member 209, the drive ring 207 and the aperture blade group 210 are driven.

FIG. 16 is an explanatory diagram of the operation of the aperture unit 200. FIG. 16A shows a state in which the aperture blades 201 are most retracted from the opening 204a of the base member 204. FIG. 16(b) shows a state in which the apertures formed by the plurality of aperture blades 201 coincide with the apertures 204a of the base member 204. FIG. 16(c) shows an intermediate aperture state, FIG. 16(d) shows a small aperture state, and FIG. 16(e) shows a minimum aperture state.

The states shown in FIGS. 16(a) to 16(e) are changed while the driving unit 205 is driven and the aperture blades 201 are changed to the minimum aperture state. In this embodiment, 13 aperture blades 201 are used, but the shape of the aperture opening can be improved by using a larger number of aperture blades. In this embodiment, the cam hole 201b of the aperture blade 201 is formed at the rear end portion on the opposite side to the direction from the fitting hole 201a toward the tip side. As the number of aperture blades 201 increases, the arrangement of the cam holes 201b like this makes it easier to move the aperture blades 201.

FIG. 17 is a plan view of the aperture blade 201 alone. The aperture blade 201 has a first convex portion 201c, a first concave portion 201d, a second convex portion 201e, and a second concave portion on the outer circumferential portion on the opposite side from the inner circumferential portion facing the opening 204a of the base member 204. 201f.

FIG. 18 is a plan view showing two extracted aperture blades 201 of the aperture unit 200 and their positions relative to the opening 204a of the base member 204. FIG. 18(a) shows the open state (state where the area of the variable aperture is maximum), and FIG. 18(b) shows the minimum aperture state. At the time of FIG. 18(a), the drive pin 207c, which is the shaft for rotating the adjacent aperture blade 201, enters the recess 201d on the outer periphery of the aperture blade 201, and the drive pin 207c, which is the shaft for rotating the adjacent aperture blade 201, enters the recess 201d on the outer periphery of the aperture blade 201. The pin 207c enters the recess 201f on the outer periphery of the aperture blade 201. Moreover, in FIG. 9(b), the first convex portion 201c and the second convex portion 201e overlap with the adjacent aperture light shielding portion 201, so that space can be effectively utilized and the aperture unit can be downsized. .

As described above, in the second embodiment, the recesses 201d and 201f are formed in the outer peripheral portion of the aperture blade 201 into which the driving pin 207c of the adjacent aperture blade and the further adjacent aperture blade 201 enter when the aperture opening is open. is formed. Thereby, even if the number of aperture blades increases, interference between the aperture blades 201 and the drive pin 207c can be avoided, and the aperture unit 200 can be made smaller.

<Third embodiment>
FIG. 19 shows an interchangeable lens 321 for a single-lens reflex camera as an imaging device equipped with the aperture unit described in the first and second embodiments, and the internal configuration of the camera body to which the interchangeable lens is attached. There is.

A photographing optical system including a variable magnification lens 332, an aperture unit 100 (200) of the first or second embodiment that narrows down the optical path, and a focus lens 329 is housed in the lens barrel of the interchangeable lens 321.

An image sensor 325 made up of a photoelectric conversion element such as a CCD sensor or a CMOS sensor is disposed within the camera body, and photoelectrically converts a subject image formed by the interchangeable lens 321 to output an electrical signal. By changing the aperture aperture of the aperture device 100 (200) or moving an ND filter (not shown) forward or backward, the brightness of the subject image formed on the image sensor 325 (that is, the amount of light that reaches the image sensor 325) can be adjusted. can be set appropriately.

The electrical signal output from the image sensor 325 is converted into a digital signal in the image processing circuit 326 and is subjected to various image processing. This generates an image signal.

By rotating the zoom ring 331, the user can move the variable power lens 332 to perform zooming. The controller 322 detects the contrast of the image signal, controls the focus motor 328 according to the contrast, moves the focus lens 329, and performs autofocus. Alternatively, the controller 322 may control the focus motor 328 and move the focus lens 329 to perform autofocus based on a detection signal from a focus detection means using a phase difference detection method (not shown).

Further, the controller 322 controls the drive section 5 (205) of the diaphragm unit 100 (200) to adjust the amount of light based on the photometric value of a photometric means (not shown) or an image signal. This makes it possible to make blur and ghosts appear more natural during shooting, and it is possible to record high-quality images.

Note that the present invention is not limited to the above-mentioned single-lens reflex camera, but is widely applicable to optical devices such as digital cameras and video cameras with integrated lenses.

The embodiments described above are merely representative examples, and various modifications and changes can be made to each embodiment when implementing the present invention.

1,201: Aperture blade, 4,204: Base member, 5,205: Drive unit, 6,206: Pinion gear, 7,207: Drive ring, 9,209: Cover member

Claims (7)

a base member having a fixed aperture through which light passes;
a plurality of light shielding blades arranged annularly in the circumferential direction of the fixed opening and forming a variable opening through which light passes;
A plurality of shafts are provided that rotate in a circumferential direction of the fixed opening with respect to the base member and engage with respective cam holes of the plurality of light shielding blades, and transmit driving force to the light shielding blades. a drive ring that rotates the plurality of light shielding blades so as to change the size of the variable aperture;
a drive source that drives the drive ring;
The light shielding blade includes a first convex portion, a first concave portion, and a second convex portion on an outer circumferential portion opposite to an inner circumferential portion facing the fixed opening,
When the area of the variable opening is maximum, the shaft for rotating the adjacent light shielding blade enters the first recess,
The light amount adjusting device, wherein the first convex portion and the second convex portion overlap the adjacent light shielding blade when the area of the variable aperture is minimum. The first convex portion, the first concave portion, and the second convex portion are arranged so that the first convex portion, the first concave portion, and the second convex portion are arranged in a direction toward the tip of the light shielding blade from the rotation center of the light shielding blade. 2. The light amount adjusting device according to claim 1, wherein the convex portion, the first concave portion, and the second convex portion are arranged in this order. The amount of light according to claim 1, wherein when the area of the variable aperture is minimum, the first recess has a portion outside the fixed aperture that does not overlap with the adjacent light shielding blade. Regulator. The light-shielding blade further includes a second concave portion closer to the tip of the light-shielding blade than the second convex portion of the outer peripheral portion, and the shaft rotates a light-shielding blade further adjacent to the adjacent light-shielding blade. 2. The light amount adjusting device according to claim 1, wherein the light amount enters the second recess. The light amount adjusting device according to claim 1, wherein a cam hole is formed in the light shielding blade, and the light shielding blade is driven to open and close by moving the shaft along the cam hole. The cam hole is formed at the rear end of the light shielding blade on the opposite side of the rotation center of the light shielding blade from the direction from the rotation center toward the tip of the light shielding blade. The light amount adjusting device according to claim 5. An imaging device comprising: the light amount adjustment device according to any one of claims 1 to 6; and an image sensor that captures an image of the light that has passed through the light amount adjustment device.

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