Aperture apparatus, lens apparatus, and image pickup apparatus

Abstract

An object of the present invention is to provide a diaphragm device having a mechanism for closing an aperture shape, in which an increase in size in a radial direction is suppressed without adding a cam plate.SOLUTION: An optical diaphragm device according to the present invention includes a plurality of diaphragm blades configured to form an aperture shape, a support member configured to rotatably support a support shaft pin of each of the diaphragm blades, and a cam member having a cam groove with which a driving pin of each of the diaphragm blades is engaged. A driving pin of the first stop blade and a driving pin of the second stop blade are engaged with the same cam groove in the cam member, and a distance between the support shaft pin and the driving pin of the second stop blade is shorter than a distance between the support shaft pin and the driving pin of the first stop blade.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The disclosure of the present specification relates to an aperture device, a lens device, and an imaging device. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there is known an aperture device in which a plurality of aperture blades are arranged at equal angular intervals on the same circumference, and the aperture opening is changed by overlapping of inner edges of the aperture blades as they rotate around a rotation axis.

[0003] In such diaphragm devices, the diaphragm blades are equipped with a rotation center pin and a drive pin. The rotation center pin is supported by a support member, and the drive pin is guided by a cam groove formed in a circular cam plate, thereby changing the aperture shape.

[0004] In addition, an aperture device is known that has a mechanism that changes the aperture diameter from the open side to the smallest opening diameter (smallest aperture diameter) of the lens device, and then further tilts the aperture blades to bring the aperture into a closed state where it is completely closed.

[0005] To close the aperture shape of the diaphragm device, the inclination angle of the diaphragm blades becomes larger. Therefore, the cam groove on the closing side needs to be extended toward the inner diameter, which increases the size of the cam plate. Furthermore, gaps may occur where the blades overlap, other than the aperture shape, resulting in light leakage. In Patent Document 1, the blades are provided with a convex shape to cover the gaps that occur when the inclination angle of the diaphragm blades increases. Furthermore, in Patent Document 2, the diaphragm device that forms the aperture shape and the shutter mechanism that achieves closing are separate units, and the cam plate of the shutter mechanism is located on the outer diameter side of the diaphragm device. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-294678 [Patent Document 2] Japanese Patent Application Publication No. 8-328084 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the mechanisms described in Patent Documents 1 and 2 have the risk of increasing the radial size of the aperture device and increasing costs due to the addition of a cam plate component, which is a precision component. [Means for solving the problem]

[0008] An aperture device according to an embodiment of the present invention comprises a plurality of aperture blades that form an aperture shape, a support member that rotatably supports support shaft pins for the aperture blades, and a cam member having a cam groove with which the drive pins of the aperture blades engage, wherein the aperture blades have a first aperture blade that forms the aperture shape and a second aperture blade that closes the aperture shape, the drive pin of the first aperture blade and the drive pin of the second aperture blade engage with the same cam groove in the cam member, and the distance between the support shaft pin and the drive pin of the second aperture blade is shorter than the distance between the support shaft pin and the drive pin of the first aperture blade. [Effects of the Invention]

[0009] In a diaphragm device having a mechanism for closing an opening shape, it is possible to realize a diaphragm device that is not enlarged in the radial direction without adding a cam plate. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is an exploded perspective view showing the aperture device 10. [Figure 2] FIG. [Figure 3] FIG. 2 is a diagram showing a first aperture blade 5. [Figure 4] FIG. 2 is a diagram showing a second diaphragm blade 6. [Figure 5] FIG. 2 is a diagram showing an aperture blade support barrel 1. [Figure 6] FIG. [Figure 7]FIG. 2 is a diagram showing the aperture device in an open state. [Figure 8] 10A and 10B are diagrams illustrating the minimum aperture state of the lens device of the aperture device. [Figure 9] FIG. 10 is a diagram showing the aperture device in a closed state. [Figure 10] FIG. 1 is a schematic diagram showing an imaging device. DETAILED DESCRIPTION OF THE INVENTION

[0011] An exemplary embodiment of the present invention will be described in detail below with reference to the drawings. In each drawing, the same components are designated by the same reference numerals, and duplicated explanations will be omitted. This embodiment relates to an aperture device used in a lens apparatus, and in particular to an aperture device whose aperture opening diameter changes when rotated.

[0012] FIG. 1 is an exploded perspective view showing the diaphragm device 10. FIG. 2 is a view showing the cam plate 3. FIG. 3 is a view showing the first diaphragm blade 5, seen from the support shaft pin side. FIG. 4 is a view showing the second diaphragm blade 6, seen from the support shaft pin side. FIG. 5 is a view showing the diaphragm blade support barrel 1. FIG. 6 is a vertical cross-sectional view of the diaphragm device 10.

[0013] As shown in Fig. 1, the diaphragm device 10 is composed of a diaphragm blade support tube 1 (support member), a plurality of diaphragm blades 2, a cam plate 3 (cam member), and a presser washer 4. An optical axis O indicates the optical axis of a lens device to which the diaphragm device is attached and fixed.

[0014] When the diaphragm device 10 is attached to a lens device, it is attached so that the center of the opening formed by the diaphragm blades 2 coincides with the optical axis of the lens device. Therefore, the optical axis is treated as synonymous with the position of the center of the opening formed by the diaphragm blades 2 and the position of the rotation center of the cam plate 3.

[0015] As shown in Figure 2, six cam grooves 31 are formed on the cam plate 3. Each cam groove 31 has an open-side allowance groove shape 31a and a small-aperture-side allowance groove shape 31b. The open-side allowance groove shape 31a is concentric with the opening diameter at which the blade whose drive pin engages with the cam groove in the open state stops being driven in the direction that changes the aperture. The small-aperture-side allowance groove shape 31b is concentric with the opening diameter at which the blade whose drive pin engages with the cam groove in the small-aperture state stops being driven in the direction that changes the aperture.

[0016] The plurality of aperture blades 2 includes a first aperture blade 5 and a second aperture blade 6 .

[0017] As shown in Fig. 3, the first diaphragm blade 5 includes a support shaft pin 5a and a drive pin 5b, and as shown in Fig. 4, the second diaphragm blade 6 includes a support shaft pin 6a and a drive pin 6b.

[0018] The support shaft pin 5a is provided in a protruding manner on one surface of the first diaphragm blade 5, and serves as the center of rotation of the first diaphragm blade 5. A drive pin 5b is provided in a protruding manner on the opposite surface of the first diaphragm blade 5. Similarly, the support shaft pin 6a is provided in a protruding manner on one surface of the second diaphragm blade 6, and serves as the center of rotation of the second diaphragm blade 6. A drive pin 6b is provided in a protruding manner on the opposite surface of the second diaphragm blade 7.

[0019] FIG. 7 is a diagram showing the fully opened aperture state of the diaphragm device 10 of this embodiment. As shown in FIG. 7, the drive pin 5b of the first diaphragm blade 5 and the drive pin 6b of the second diaphragm blade 6 engage with the same cam groove 31. As shown in FIGS. 3 and 4, the angles P and Q of the first diaphragm blade 5 and the second diaphragm blade 6 are different from each other. The angle P shown in FIG. 3 is the angle formed by two lines passing through the support shaft pin 5a and drive pin 5b of the first diaphragm blade 5 and having their intersection at the aperture center O (optical axis O). The angle Q shown in FIG. 4 is the angle formed by two lines passing through the support shaft pin 6a and drive pin 6b of the second diaphragm blade 6 and having their intersection at the aperture center O (optical axis O).

[0020] Specifically, the angle Q formed by the second diaphragm blade 6 is set smaller than the angle P formed by the first diaphragm blade 5. In other words, the distance between the support shaft pin 6a and the drive pin 6b of the second diaphragm blade 6 is shorter than the distance between the support shaft pin 5a and the drive pin 5b of the first diaphragm blade 5. As a result, the second diaphragm blade 6 has a higher sensitivity to tilt per rotation angle of the cam plate 3 relative to the cam groove 31 than the first diaphragm blade 5.

[0021] The diaphragm blades 2 of this embodiment are composed of six first diaphragm blades 5 and six second diaphragm blades 6. As shown in FIG. 5, engagement holes 1a and 1b are formed in the diaphragm blade support tube 1. A support shaft pin 5a of the first diaphragm blade 5 engages with the engagement hole 1a, and a support shaft pin 6a of the second diaphragm blade 6 engages with the engagement hole 1b. The support shaft pin 5a is rotatably supported by the engagement hole 1a. Furthermore, the support shaft pin 6a is rotatably supported by the engagement hole 1b.

[0022] 5 and 7, engagement hole 1b of diaphragm blade support barrel 1 is positioned closer to open-side margin groove shape 31a of cam groove 31 than engagement hole 1a. As a result, when the diaphragm opening is changed from fully open to the small aperture (when cam plate 3 is rotated), second diaphragm blade 6 does not initially drive, but starts to drive after first diaphragm blade 5 starts to drive.

[0023] 1 and 6, on the side where the drive pins 5b and 6b of the multiple diaphragm blades 2 (first diaphragm blade 5, second diaphragm blade 6) are provided, a cam plate 3 is arranged rotatably relative to the diaphragm blade support barrel 1 around the optical axis center O. The first diaphragm blade 5 and the second diaphragm blade 6 are sandwiched between the cam plate 3 and the diaphragm blade support barrel 1, and their positions along the optical axis O are determined by the presser washer 4.

[0024] With this configuration, in the diaphragm device 10, when the cam plate 3 is rotated around the optical axis O relative to the diaphragm blade support barrel 1, the drive pins 5b and 6b are each guided along the cam groove 31. When guided along the cam groove 31, the drive pin 5b is positioned more inwardly than the drive pin 6b. The first diaphragm blade 5 rotates around the support shaft pin 5a supported in the engagement hole 1a, and the second diaphragm blade 6 rotates around the support shaft pin 6a supported in the engagement hole 1b.

[0025] 8 is a diagram showing the minimum aperture state of the lens device in the diaphragm device 10 of this embodiment. The minimum aperture state is a state in which an opening is formed by the first diaphragm blade 5.

[0026] 9 is a diagram showing a closed state (closing state) in which the aperture of the diaphragm device 10 of this embodiment is closed. In the closed state, the aperture is closed by the second diaphragm blade 6.

[0027] In the diaphragm device 10, from the fully open state (FIG. 7) to the minimum aperture state (FIG. 8) of the lens device, the aperture is formed only by the inner edge 51 (see FIG. 3) of the first diaphragm blade 5. The shape of the inner edge 51 of the first diaphragm blade 5 is set so that when the aperture is formed only by the first diaphragm blade 5, the shape of the aperture is approximately circular.

[0028] The aperture device 10 achieves the closed state by the second aperture blade 6 when the lens device is in the minimum aperture state (Figure 8) to the closed state (Figure 9) by positioning the inner edge 61 (see Figure 4) of the second aperture blade 6 toward the center within the opening formed by the inner edge 51 of the first aperture blade 5.

[0029] In the aperture diaphragm device 10 of this embodiment, in the fully open state (FIG. 7), the inner edge 61 of the second aperture leaf 6 is disposed on the outer diameter side of the inner edge 51 of the first aperture leaf 5. This makes it easier to prevent the inner edge 61 of the second aperture leaf 6 from protruding into the opening shape due to component play or the like in the open-side opening shape.

[0030] Furthermore, after the minimum aperture of the lens device is formed, the first aperture blade 5 is driven toward the small aperture side for a predetermined period of time, and then the drive pin 5b engages with the small aperture side margin groove shape 31b. This makes it easier to prevent the inner edge 61 of the second aperture blade 6 from protruding into the opening shape due to component play or the like before the minimum aperture of the lens device is formed.

[0031] In the diaphragm device 10 of this embodiment, the aperture is closed by the second diaphragm blade 6, so there is no need to tilt the first diaphragm blade 5 to the closed state after forming the minimum aperture of the lens device. This reduces the gap between the multiple diaphragm blades, eliminating the need to enlarge the shape of the diaphragm blade 2 to prevent light leakage. This allows the diaphragm device to be made smaller and lighter.

[0032] Similarly, the cam plate 3 does not need to have a cam groove 31 formed thereon to allow the first diaphragm blade 5 to move to the closed state, so its width can be narrowed. This allows for the diaphragm device to be made smaller and lighter.

[0033] Furthermore, since the first diaphragm blade 5 and the second diaphragm blade 6 are driven by the same cam groove 31, there is no need to add a new cam plate. This allows for a smaller, lighter, and less costly diaphragm device. Furthermore, since there is only one cam plate 3, the cam groove 31 within the same component is shared, improving the precision of the aperture shape.

[0034] Fig. 10 is a schematic diagram showing an imaging device 400. As shown in Fig. 10, the imaging device 400 includes a lens device 100 and a camera body 300. The camera body 300 includes an imaging element 200. The imaging element 200 receives light from the lens device 100. The lens device 100 includes the above-mentioned diaphragm device 10 and a lens unit 110 that guides light from an object to the diaphragm device. The lens device 100 is attached to the camera body 300. The lens device 100 may be detachable from the camera body 300, or may be integrated with the camera body 300.

[0035] The lens device 100 includes the diaphragm device 10, and therefore can realize the lens device 100 that can obtain the effects of the diaphragm device 10. Furthermore, the imaging device 400 includes the lens device 100 that has the diaphragm device 10, and therefore can realize the imaging device 400 that can obtain the effects of the diaphragm device 10.

[0036] <Other embodiments> Although the 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 of the present invention.

[0037] In the above-described embodiment, the support shaft pin 5a of the first diaphragm blade 5 engages with the engagement hole 1a of the diaphragm blade support barrel 1, and the support shaft pin 6a of the second diaphragm blade 6 engages with the engagement hole 1b of the diaphragm blade support barrel 1. The present invention is not limited to this configuration, and includes configurations that can achieve similar effects.

[0038] For example, a support shaft pin may be provided on the diaphragm blade support barrel 1, and this support shaft pin may be configured to engage with a rotation center hole formed in the first diaphragm blade 5 and the second diaphragm blade 6.

[0039] Disclosure of embodiments of the present invention includes the following configurations.

[0040] (Configuration 1) a plurality of aperture blades that form an aperture shape; a support member that rotatably supports a support shaft pin of the diaphragm blade; In a diaphragm device having a cam member having a cam groove with which the drive pin of the diaphragm blade engages, The aperture blades are a first aperture blade that forms an aperture shape; a second diaphragm blade that closes the aperture shape; a drive pin of the first diaphragm blade and a drive pin of the second diaphragm blade engage with the same cam groove in the cam member, A diaphragm device, characterized in that the distance between the support shaft pin and the drive pin of the second diaphragm blade is shorter than the distance between the support shaft pin and the drive pin of the first diaphragm blade.

[0041] (Configuration 2) The aperture device according to configuration 1, wherein the support shaft pin of the second aperture blade of the support member is arranged closer to the open side of the cam groove than the support shaft pin of the first aperture blade.

[0042] (Configuration 3) 3. The diaphragm device according to configuration 1 or 2, wherein, in an open state of the diaphragm device, an inner edge portion of the second diaphragm blade is disposed on the outer diameter side of an inner edge portion of the first diaphragm blade.

[0043] (Configuration 4) 4. The aperture device according to any one of configurations 1 to 3, wherein when the aperture shape is changed by the plurality of aperture blades, the drive pin of the first aperture blade is positioned on the inner diameter side of the drive pin of the second aperture blade.

[0044] (Configuration 5) 5. The diaphragm device according to any one of configurations 1 to 4, wherein the inclination of the first diaphragm blade does not change when the aperture shape changes from the minimum aperture of the diaphragm device to a closed state.

[0045] (Configuration 6) The diaphragm device according to any one of configurations 1 to 5, characterized in that it includes a state in which the inclination of the second diaphragm blade does not change when the opening shape changes from the fully opened state of the diaphragm device to the minimum aperture side.

[0046] (Configuration 7) The aperture device according to any one of configurations 1 to 6, A lens device comprising a lens unit that guides light from an object to the diaphragm device.

[0047] (Configuration 8) the lens device according to configuration 7; An imaging device comprising: a camera body having an imaging element that receives light from the lens device. [Explanation of symbols]

[0048] 1 Diaphragm blade support tube (support member) 2 aperture blades 3 Cam plate (cam component) 31 Cam groove 5 First aperture blade 5a Support shaft pin 5b Drive pin 6 Second aperture blade 6a Support shaft pin 6b Drive pin 10. Aperture device

Claims

1. a plurality of aperture blades that form an aperture shape; a support member that rotatably supports a support shaft pin of the diaphragm blade; In a diaphragm device having a cam member having a cam groove with which the drive pin of the diaphragm blade engages, The aperture blades are a first aperture blade that forms an aperture shape; a second diaphragm blade that closes the aperture shape; a drive pin of the first diaphragm blade and a drive pin of the second diaphragm blade engage with the same cam groove in the cam member, A diaphragm device, characterized in that the distance between the support shaft pin and the drive pin of the second diaphragm blade is shorter than the distance between the support shaft pin and the drive pin of the first diaphragm blade.

2. 2. The aperture device according to claim 1, wherein the support shaft pin of the support member for the second aperture blade is disposed closer to the open side of the cam groove than the support shaft pin of the first aperture blade.

3. 2. The diaphragm device according to claim 1, wherein, in an open state of the diaphragm device, an inner edge portion of the second diaphragm blade is disposed on an outer diameter side of an inner edge portion of the first diaphragm blade.

4. 2. The aperture device according to claim 1, wherein when the aperture shape is changed by the plurality of aperture blades, the drive pin of the first aperture blade is positioned on the inner diameter side of the drive pin of the second aperture blade.

5. 2. The diaphragm device according to claim 1, wherein the inclination of the first diaphragm blade does not change when the aperture shape changes from the minimum aperture of the diaphragm device to a closed state.

6. 2. The diaphragm device according to claim 1, wherein the inclination of the second diaphragm blade does not change when the aperture shape changes from the fully opened state of the diaphragm device to the minimum aperture side.

7. The aperture device according to any one of claims 1 to 6, A lens device comprising a lens unit that guides light from an object to the diaphragm device.

8. The lens device according to claim 7 ; An imaging device comprising: a camera body having an imaging element that receives light from the lens device.

Images