Diaphragm device and imaging apparatus

Abstract

To provide a diaphragm device and an imaging apparatus that can be stably driven.SOLUTION: In order to solve the above-mentioned problem, a diaphragm device of the present invention is a diaphragm device comprising: a plurality of diaphragm blades 106 that come in and out of a light passage path; a rotation member 104 that drives the diaphragm blades 106; a holding member 105 that holds the rotation member 104 rotatably inside an opening; and a driving source that applies a driving force to the rotation member 104 via a gear. The gear 103 and a contact surface of the rotation member 104 with the diaphragm blades 106 are connected with each other through the inside of the opening of the holding member 105. A slide surface of the rotation member 104 with the diaphragm blades 106 is on one surface of the holding member 105. The gear 103 is arranged on the other surface of the holding member 105.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to an aperture device mounted in an optical device such as an imaging device or an interchangeable lens, and to an imaging device. [Background technology]

[0002] The shape of the aperture formed in the aperture device as a light passage opening is preferably as close to circular as possible, and in order to form an aperture that is close to circular, three or more aperture blades (light amount adjustment blades) are often used. Also, a polygonal aperture that is close to circular is formed by rotating the multiple aperture blades using a rotating member that can rotate around a fixed aperture formed in a base member (aperture forming member). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-90464 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in an aperture device such as that described in Patent Document 1, to prevent contact between the gear portion of the rotating member and the aperture blades, the aperture blades and the gear portion must be spaced a certain distance (in the radial or thickness direction), which results in a problem of a large aperture device. Furthermore, the base member that rotatably holds the rotating member has a complex part shape due to the gear portion of the rotating member, the connection shape from the gear portion to the blade sliding surface, and the notches to prevent collision with the base member, making it difficult to finish the part with precision. Furthermore, if there are multiple blades arranged in a ring and some of them have different contact conditions with other parts, differences in the movement of the blades can occur.

[0005] To provide an aperture device that is small in size but can increase the precision of parts by simplifying the shapes of the base member and the rotating member, and can operate stably by making the contact state between each aperture blade and the base member and the rotating member uniform. [Means for solving the problem]

[0006] In order to solve the above problem, the aperture device of the present invention is an aperture device comprising a plurality of aperture blades that move in and out of a light passage path, a rotating member that drives the aperture blades, a holding member that rotatably holds the rotating member inside an opening, and a drive source that provides driving force to the rotating member via a gear, wherein the contact surface of the rotating member with the aperture blades and the gear are connected through the inside of the opening of the holding member, and one side of the holding member has a sliding surface of the rotating member that comes into contact with the aperture blades, and the gear is arranged on the other side of the holding member. [Effects of the Invention]

[0007] The aperture device and imaging device according to the present invention are small in size, yet can achieve a good quality aperture shape with stable driving. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is an exploded perspective view of a diaphragm device according to a first embodiment. [Figure 2] Perspective view of the aperture device [Figure 3] Front view of the aperture device (A) Full aperture (B) Medium aperture (C) Small aperture [Figure 4] Front view of the aperture device (cam member not shown) (A) Full aperture state (B) Medium aperture state (C) Small aperture state [Figure 5] Front view of the aperture device (cam member and aperture blades not shown) [Figure 6] Front view of the aperture device (cam member, aperture blades, and base member not shown) [Figure 7] Cross-sectional view of the aperture device [Figure 8]Cross-sectional view of the aperture device in small aperture state [Figure 9] 1 is a schematic diagram of an imaging device equipped with a light amount adjustment device according to a first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0010] <Embodiment 1> FIG. 1 shows an exploded perspective view of an aperture stop device according to a first embodiment of the present invention. FIG. 2 is a perspective view of the aperture stop device according to the first embodiment. FIG. 1 shows an optical axis center 100 of the aperture stop device and a drive unit 101 that operates the aperture stop device. Examples of this drive unit 101 include a stepping motor and a galvanometer. A pinion 103 is attached to the rotation axis of this drive unit 101.

[0011] The cover member 102 is an opening-forming member having an opening 102a formed in the center thereof. In this embodiment, the cover member 102 is formed by, for example, resin molding.

[0012] In this embodiment, the rotating member 104 is, for example, a circular member formed by resin molding, and is an opening-forming member (rotating member) having a circular opening 104a formed in the center thereof, which serves as a path for light to pass through.

[0013] The rotating member 104 has multiple drive holes 104b, a rotational engagement portion 104d that rotatably engages with a base member 105 (described later), and a sliding surface 104f with aperture blades 106 (described later). The sliding surface 104f is preferably circular or axially symmetrical in accordance with the number of blades so that the multiple aperture blades can slide over the surface under the same conditions. The rotating member 104 also has a gear portion that serves as a driven portion 104e. The driven portion 104e is engaged with a pinion 103. The rotational force generated by the driving portion 101 is transmitted from the pinion 103 to the driven portion 104e, thereby rotating the rotating member 104. For example, in this embodiment, the rotational force of the driving portion 101 is transmitted directly from the pinion 103 to the rotating member 104. However, an intermediate gear (including a reduction gear, etc.) may be used between the pinion 103 and the rotating member 104. Although not shown, a light-shielding portion is provided on the rotating member 104, and the light-shielding portion moves in and out of a slit in a photointerrupter or the like, thereby making it possible to detect positions such as the initial position of the diaphragm device. In addition, by providing a stopper 104k on the rotating member 104, the rotation angle can be restricted by contacting a stopper portion 105k of the base member 105, which will be described later.

[0014] The base member 105 is an aperture-forming member having an aperture 105a formed in the center. In this embodiment, the base member 105 is formed by, for example, resin molding. The base member 105 has an engagement portion 105d with which the rotating member 104 rotatably engages. The engagement portion 105d is formed by protruding inward from the central aperture 105a. In this embodiment, the engagement portion 105d is formed with multiple protrusions, and the rotating member 104 rotatably engages with the engagement portion 105d, thereby minimizing the contact area with the rotating member and reducing the influence of friction on operation. However, multiple protrusions may be provided on the rotation engagement portion 104d of the rotating member 104, and the base member 105 side may rotatably engage with the aperture 105a (round hole). The base member 105 also has a sliding surface 105f1 with which the aperture blade 106, which will be described later, slides. The sliding surface 105f1 is preferably a surface that is axially symmetrical with respect to the optical axis center 100 within the sliding range of the diaphragm blades 106 so that the plurality of diaphragm blades 106 can slide under the same conditions (contact area, angle, height, surface condition, etc.). In the first embodiment, it is desirable that the opening 105a has a circular shape that is connected all around in the center of the base member 105, and that the opening 105a and the sliding surface 105f1 are connected to each other.

[0015] The base member 105 also has a sliding surface 105f2 with the rotating member 104 and a stopper 105k on the surface opposite the sliding surface 105f1, and also has a stopper 104k that restricts the rotation angle of the rotating member 104. When attaching a sensor that detects the initial position of the diaphragm device, it is preferable to attach it to the surface opposite the sliding surface 105f1 with the diaphragm blade 106. By arranging the stopper 105k, sensor mounting shape, and gear connection structure on the surface of the base member 105 opposite the sliding surface 105f1 with the blade, the shape of the sliding surface side of the blade can be simplified. Furthermore, the rotating member 104 and the base member 105 can be rotatably engaged between the sliding surface 105f1 and the opposite surface 105f2 in the direction of the light transmission path, thereby making effective use of space.

[0016] Furthermore, base member 105 has an attachment positioning portion 105g for cam member 107, which will be described later. By setting this attachment positioning portion 105g coaxially with optical axis 100, the accuracy of alignment with cam member 107 is improved, and the accuracy of the diaphragm shape formed by diaphragm blades 106 is improved. It is preferable to determine the center with attachment positioning portion 105g of base member 105 and determine the phase of cam member 107 with rotation stop shaft 105h, but it is also possible to eliminate rotation stop shaft 105h and determine the attachment phase of cam member 107, which will be described later, while adjusting the diaphragm diameter (light amount), and then fix it with screws, etc.

[0017] In this embodiment, for example, multiple (seven) diaphragm blades 106 are arranged in a ring shape to surround an opening through which light passes. Each diaphragm blade 106 is formed with an engagement shaft 106d and a cam shaft 106c, which are driven parts. Such diaphragm blades 106 may be made, for example, by forming a shaft on a PET sheet material or the like and then pressing it, or by resin molding. Although this embodiment is configured with seven diaphragm blades, the number of diaphragm blades may be any number greater than or equal to three. The maximum opening of the portion through which light passes may be determined by the opening 104a of the rotating member 104, the opening 102a of the cover member 102, or the opening 107a of the cam member 107, which will be described later, or may be determined by the ends of the multiple diaphragm blades 106.

[0018] The cam member 107 houses the above-mentioned multiple diaphragm blades 106 between the rotating member 104 and the base member 105, and forms a blade chamber in which the blades move between the rotating member 104 and the base member 105. That is, the multiple diaphragm blades 106 move (drive) in the blade chamber (space) formed by the base member 105, the rotating member 104, and the cam member 107 as the rotating member 104 rotates. The cam member 107 is formed with an opening 107a that communicates with the opening of the base member 105, and serves as an opening forming member similar to the base member 105. The cam member 107 may be formed by resin molding or the like.

[0019] The engagement shaft 106b of the diaphragm blade 106 engages with the drive hole 104b of the rotating member 104. When the pinion 103 rotates, a force is applied to the driven portion 104e of the rotating member 104, causing the rotating member 104 to rotate. Then, a driving force is applied from the drive hole 104b of the rotating member 104 to the engagement shaft 106b of the diaphragm blade 106, driving the diaphragm blade 106. At this time, the cam shaft 106c of the diaphragm blade 106 engages with the engagement portion 107c of the cam member 107. Therefore, the cam groove 107c allows the diaphragm blade 106 to move in and out of the opening of the cam member 107. As a result, the diaphragm shape is adjusted by the multiple diaphragm blades 106 within the opening 107a of the cam member 107, making it possible to adjust the amount of light passing through.

[0020] FIG. 3(A) shows the aperture of the aperture device in a fully opened state, FIG. 3(B) shows the aperture in an intermediate state, and FIG. 3(C) shows the aperture in a small state.

[0021] 4 shows the state in which the cam member 107 has been removed, with FIG. 4(A) showing the fully opened aperture, FIG. 4(B) showing the intermediate aperture, and FIG. 4(C) showing the small aperture.

[0022] Fig. 5 shows the state where the cam member 107 and the diaphragm blades 106 have been removed. Fig. 6 shows the state where the cam member 107, the diaphragm blades 106, and the base member have been removed. Fig. 7 shows a cross-sectional view of the first embodiment. Fig. 8 shows a cross-sectional view in the small aperture state.

[0023] The plurality of aperture blades 106 are arranged in a ring shape so that the front and back of adjacent aperture blades overlap each other, and the tips of the aperture blades are woven in one direction.

[0024] In the first embodiment, the knitting direction of the tip of the diaphragm blade is the opposite direction (toward the cam member 107) to the rotating member 104. Because the diaphragm blade 106 is made of an elastic material, when the tip of the diaphragm blade is knitted in direction A, a force (reaction force) acts on the diaphragm blade 106 to return to its original flat shape, and therefore a force is generated in direction B on the cam shaft 106c and engagement shaft 106d side, which are opposite the tip side of the diaphragm blade.

[0025] In the first embodiment, each diaphragm blade 106 generates an equal force in the direction B, and it is desirable that both the rotating member 104 and the base member 105 receive the force in the direction B from each diaphragm blade equally in the same state. If the shapes of the rotating member 104 and the base member 105 that receive the force in the direction B are partially different, the balance of the load on the finished blades may be disrupted, and within the range of play between the components, there is a possibility that the aperture shape formed by the multiple diaphragm blades 106 may become uneven. For example, rather than having a portion of the sliding surface 104f of the rotating member 104 that contacts the diaphragm blade 106 formed by a gear, it is desirable that the outer periphery of the sliding surface 104f is circular, as in the present application, and that the inner periphery of the sliding surface 105f1 of the base member 105 is also circular. If the sliding surface 104f is not circular, it is desirable that it be axially symmetrical according to the number of diaphragm blades. Furthermore, it is desirable that the sliding surface 105f1 between the base member 105 and the diaphragm blades 106 is axially symmetrical to match the number of diaphragm blades 106, as in the present application, rather than having a shape with partial cutouts (Prior Art 1). If the mating surface that transmits the force in direction B of each diaphragm blade 106 has the same shape, the force tending to deflect each diaphragm blade 106 will also be uniform, resulting in a stable diaphragm shape. The inscribed circle / circumscribed circle of the diaphragm shape is sometimes called the circularity as an index of the diaphragm shape, and it is possible to realize an diaphragm device with a stable and high circularity.

[0026] Furthermore, it is desirable that the surface that receives the force in direction B has rigidity. For example, it is a metal part, a resin molded part, etc. In other words, if the base member 105 and the rotating member 104 have greater rigidity than the diaphragm blade 106, the diaphragm blade 106 will bend stably, resulting in stable performance.

[0027] Next, this first embodiment is effective in reducing the outer diameter relative to the center of the optical axis. The base member 105 and the rotating member 104 are engaged with each other at the engagement portion 105d and the rotational engagement portion 104d, and by positioning this engagement portion so that it overlaps with the operating range of the diaphragm blade 106 in the optical axis direction, this is effective in reducing the outer diameter. Furthermore, with this configuration, the operating area of ​​the diaphragm blade 106 and the rotational engagement portion 104d of the rotating member 104 can be adjacent to each other, which is also effective in saving space.

[0028] Furthermore, it is preferable that engagement portion 104b of diaphragm blade 106 of rotating member 104 is located inside the rotational engagement portion between rotating member 104 and base member 105. The closer the point at which rotating member 104 applies force to diaphragm blade 106 is to the center of rotating member 104, the more the operating load can be reduced. In other words, this is effective for power saving, high-speed operation, etc.

[0029] Furthermore, sliding surface 104f of rotating member 104 is connected to a gear portion, which is driven portion 104e of rotating member 104, via rotational engagement portion 104d, which is an engagement portion with base member 105. In other words, sliding surface 104f of rotating member 104 and driven portion 104e can be connected through opening 105a in the center of base member 105, so there is no need to form a separate connecting shape outside rotational engagement portion 104d of base member 105, which is effective for miniaturization. Furthermore, by setting the driven portion 104e at a position that overlaps the operating range of the diaphragm blade 106 in the optical axis direction, it is effective in reducing the outer diameter.

[0030] Since the outer diameter of the aperture device can be reduced, this is also effective in miniaturizing the imaging device in which the aperture device is installed. It also makes it easier to arrange a zoom mechanism, focus mechanism, image stabilization mechanism, etc. around the aperture device. Furthermore, while smartphones and other devices are currently equipped with multiple lenses, the aperture device of the present application has a small outer diameter, making it possible to shorten the distance between the lenses.

[0031] Furthermore, an imaging device equipped with the above-described diaphragm device can obtain the effects of the above-described diaphragm device, and is effective in achieving miniaturization, stable driving, and a good diaphragm shape.

[0032] Example 2 FIG. 9 shows an interchangeable lens 301 for a single-lens reflex camera, which is an imaging device equipped with the light amount adjustment device described in the first embodiment, and the internal configuration of the camera body to which the interchangeable lens is attached.

[0033] The lens barrel of the interchangeable lens 301 houses a photographing optical system including a variable magnification lens 307, a light amount adjustment device 300 of the first embodiment that narrows the optical path, and a focus lens 305.

[0034] An image sensor 303, which is composed of a photoelectric conversion element such as a CCD sensor or a CMOS sensor, is disposed inside the camera body and photoelectrically converts the subject image formed by the interchangeable lens 301 to output an electrical signal. The brightness of the subject image formed on the image sensor 303 (i.e., the amount of light reaching the image sensor 303) can be appropriately set by changing the aperture of the light amount adjustment device 300 or by moving an ND filter (not shown) forward or backward.

[0035] The electrical signal output from the image sensor 303 is converted into a digital signal in the image processing circuit 304 and subjected to various image processing, thereby generating an image signal.

[0036] A user can change the magnification (zoom) by moving a variable magnification lens 307 by rotating a zoom ring 306. The controller 302 detects the contrast of an image signal, controls a focus motor 304 in accordance with the contrast, and moves a focus lens 305 to perform autofocus. Alternatively, the controller 302 may control the focus motor 304 based on a detection signal from a focus detection means using a phase difference detection method (not shown), and moves a focus lens 229 to perform autofocus.

[0037] Furthermore, the controller 302 controls the drive unit 1 of the light amount adjustment device 300 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 ghosting during shooting appear natural, and to record high-quality images.

[0038] The present invention is not limited to the single-lens reflex camera described above, but can also be widely applied to optical devices such as digital cameras with an integrated lens, video cameras, and the like. [Explanation of symbols]

[0039] 101 Aperture drive unit 102 Cover member (opening forming member) 103 Pinion gear 104 Rotating member 105 base member (opening forming member) 106 aperture blades 107 Cam member

Claims

1. a plurality of aperture blades that move in and out of a light passageway; a rotating member that drives the diaphragm blades; a holding member that rotatably holds the rotating member inside the opening; a drive source that applies a drive force to the rotating member via a gear, An aperture device characterized in that the contact surface of the rotating member with the aperture blade and the gear are connected through the inside of the opening of the holding member, one surface of the holding member has a sliding surface of the rotating member with the aperture blade, and the gear is arranged on the other surface of the holding member.

2. The aperture device of claim 1, The aperture device is characterized in that the opening of the holding member is circular.

3. The aperture device of claim 1, An aperture device characterized in that the shapes of the holding member and the rotating member on which the multiple aperture blades slide are axially symmetrical with respect to the optical axis center axis of the light passage path, in accordance with the number of aperture blades.

4. The aperture device of claim 1, The aperture device is characterized in that the rotating member rotates while sliding on the inside of the opening of the holding member.

5. 2. The diaphragm device according to claim 1, wherein the driving ranges of the plurality of diaphragm blades overlap with the gear and the engagement surfaces of the rotating member and the holding member in the direction of the light passage path.

6. An optical instrument comprising the diaphragm device according to any one of claims 1 to 5.

Images