Light-shielding unit and lens barrel with the same

Abstract

To suppress foreign matters from entering a blade chamber through a through-hole leading to the blade chamber for storing multiple diaphragm blades, the through-hole being in a member defining the blade chamber within a lens barrel.SOLUTION: A light shielding unit includes: a plurality of diaphragm blades 34; a base member 32 rotatably supporting the diaphragm blades 34; a cover member 42 attached to the base member 32, the cover member and the base member defining a blade chamber BR storing the diaphragm blades 34; and an annular first sheet 38 between the base member 32 and the diaphragm blades 34 in the blade chamber BR, the diaphragm blades 34 smoothly moving on the first sheet. The base member 32 has a through-hole 32g leading to the blade chamber BR, and the first sheet 38 covers the through-hole 32g.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present disclosure relates to a light-shielding unit for adjusting the amount of light passing through a lens barrel and a lens barrel including the same.

Background Art

[0002] Patent Document 1 discloses a lens barrel including a light-shielding unit. The light-shielding unit includes a plurality of aperture blades, a drive ring that drives the plurality of aperture blades, a base member that supports these, and a cover member that is attached to the base member and defines a blade chamber that stores the plurality of aperture blades in cooperation with the base member.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in manufacturing, a through hole communicating with the blade chamber may be formed in the base member. In this case, foreign matter may enter the blade chamber through the through hole. When foreign matter enters the blade chamber, there is a risk that the foreign matter gets between the aperture blades and makes it difficult or impossible for some of the aperture blades to rotate.

[0005] Therefore, an object of the present disclosure is to suppress the intrusion of foreign matter into the blade chamber through a through hole in a lens barrel in which a through hole communicating with a blade chamber for storing a plurality of aperture blades exists in a member that defines the blade chamber.

Means for Solving the Problems

[0006] In order to solve the above problems, according to one aspect of the present disclosure, a plurality of aperture blades, A base member that rotatably supports each of the plurality of aperture blades, A cover member that is attached to the base member and defines a blade chamber that cooperates with the base member to store the plurality of aperture blades, An annular first sheet disposed between the base member and the plurality of aperture blades in the blade chamber, on which the plurality of aperture blades slide, and having, The base member includes a through hole that communicates with the blade chamber, A light-shielding unit is provided in which the first sheet covers the through hole.

[0007] Further, according to another aspect of the present disclosure, At least one lens, And the light-shielding unit, a lens barrel is provided.

Advantages of the Invention

[0008] According to the present disclosure, in a lens barrel in which a through hole communicating with a blade chamber for storing a plurality of aperture blades exists in a member that defines the blade chamber, it is possible to suppress the intrusion of foreign matter into the blade chamber through the through hole.

Brief Description of the Drawings

[0009]

Figure 1

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Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, a more detailed description than necessary may be omitted. For example, a detailed description of well-known matters and a redundant description of substantially the same configuration may be omitted. This is to avoid making the following description unnecessarily redundant and to facilitate the understanding of those skilled in the art.

[0011] Note that the inventor(s) provide the accompanying drawings and the following description so that those skilled in the art can fully understand the present disclosure, and do not intend to limit the subject matter described in the claims thereby.

[0012] Hereinafter, a lens barrel according to an embodiment of the present disclosure will be described with reference to the drawings.

[0013] FIG. 1 is a front perspective view of a lens barrel according to an embodiment of the present disclosure. Further, FIG. 2 is a rear perspective view of the lens barrel. And FIG. 3 is a schematic cross-sectional view of the lens barrel.

[0014] Here, the X-Y-Z orthogonal coordinate system shown in the figure is for facilitating the understanding of the embodiment of the present disclosure, and does not limit the embodiment of the present disclosure. The Z-axis direction is the extending direction of the optical axis of the lens barrel, and the X-axis direction and the Y-axis direction are directions orthogonal to the extending direction of the optical axis. In this specification, "front side (F)" is the subject side, and "rear side (R)" is the imaging device side.

[0015] As shown in FIGS. 1 to 3, the lens barrel 10 according to the present embodiment includes a plurality of lenses 12 to 20. The lens 12 is the lens closest to the subject side, and the lens 14 is the lens closest to the imaging device side. Further, the lens barrel 10 has a light shielding unit 30 that is disposed between the lenses 16 and 18 and adjusts the amount of light passing through the lens barrel 10.

[0016] FIG. 4 is a front perspective view of the light shielding unit with the aperture blades 34 opened. FIG. 5 is a rear perspective view of the light shielding unit with the aperture blades 34 opened. Further, FIG. 6 is a front perspective view of the light shielding unit with the aperture blades 34 closed. Furthermore, FIG. 7 is a front exploded perspective view of the light shielding unit. And FIG. 8 is a rear exploded perspective view of the light shielding unit.

[0017] As shown in FIGS. 7 and 8, the light shielding unit 30 includes a base member 32, a plurality of aperture blades 34, a drive ring 36 that drives the plurality of aperture blades 34, a first sheet 38 disposed on the front side with respect to the plurality of aperture blades 34, a second sheet 40 disposed on the rear side with respect to the plurality of aperture blades 34, and a cover member 42.

[0018] The base member 32 generally has a shape in which a cylindrical wall extends from a substantially annular end face toward the rear portion of the lens barrel 10. The base member 32 houses the plurality of aperture blades 34, the drive ring 36, the first sheet 38, and the second sheet 40.

[0019] The plurality of aperture blades 34 are members for adjusting the amount of light passing through the lens barrel 10. In the case of this embodiment, the light shielding unit 30 includes nine aperture blades 34 having the same shape. Each of the plurality of aperture blades 34 is supported by the base member 32 so as to be rotatable about a rotation center line extending in the extending direction (Z-axis direction) of the optical axis C of the lens barrel 10. For this purpose, each of the plurality of aperture blades 34 is provided with a through hole 34a, and the base member 32 is provided with a plurality of support pins 32a passing through the respective through holes 34a. When the plurality of aperture blades 34 rotate, the light shielding unit 30 becomes the open state shown in FIG. 4 or the closed state shown in FIG. 6. That is, when the plurality of aperture blades 34 rotate, the opening area of the opening 30a of the light shielding unit 30 through which light passes changes, and as a result, the amount of light passing through the light shielding unit 30 changes.

[0020] The drive ring 36 is a ring-shaped member and is disposed between the base member 32 and the plurality of aperture blades 34. Further, the drive ring 36 is supported by the base member 32 so as to be rotatable about the optical axis C. When the drive ring 36 rotates, each of the plurality of aperture blades 34 is driven from the open state shown in FIG. 4 to the closed state shown in FIG. 6 or vice versa. For this purpose, each of the plurality of aperture blades 34 is provided with a cam groove 34b, and the drive ring 36 is provided with a plurality of pin-shaped cam followers 36a that follow in the respective cam grooves 34b.

[0021] Also, in the case of this embodiment, the drive ring 36 is rotationally driven by the motor 44. For this purpose, the light shielding unit 30 has a drive gear 46 attached to the motor 44 and a power transmission gear 48 that meshes with the drive gear 46. The power transmission gear 48 includes a large-diameter gear portion 48a that meshes with the drive gear 46 and a small-diameter gear portion 48b that meshes with gear teeth 36b formed on the drive ring 36. Note that the power transmission gear 48 is supported by a support pin 32b provided on the base member 32.

[0022] The motor 44 is electrically connected to the contact terminal 52 shown in FIG. 1 via the flexible printed circuit board 50. Thereby, the motor 44 is electrically connected to the imaging device via the contact terminal 52. Further, the motor 44 is fixed to the base member 32 by the fixing screw 54, and the flexible printed circuit board 50 is fixed to the base member 32 via the fixing screw 56. As shown in FIG. 8, a position sensor 58 for detecting the rotation angle of the drive ring 36 (specifically, the position of the tongue piece 36c provided on the drive ring 36) is mounted on the flexible printed circuit board 50.

[0023] The first and second sheets 38 and 40 are annular sheet members in which the openings 38a and 40a are formed, and are made of a material having light-shielding properties and smoothness, for example, a PET sheet. The first sheet 38 is disposed between the base member 32 and the plurality of aperture blades 34. The second sheet 40 is disposed between the plurality of aperture blades 34 and the cover member 42. That is, the first and second sheets 38 and 40 are provided in the light-shielding unit 30 in a state of sandwiching the plurality of aperture blades 34 in the extending direction of the optical axis C (Z-axis direction). In the case of the present embodiment, the diameter of the opening 40a of the second sheet 40 is the aperture of the lens barrel 10.

[0024] While sliding on the surfaces of the first and second sheets 38 and 40, the plurality of aperture blades 34 are rotated by the drive ring 36. The first and second sheets 38 and 40 having smoothness enable the drive ring 36 to be rotated with low torque. The first and second sheets 38 and 40 include engagement holes 38b and 40b that engage with the support pins 32a of the base member 32, and long holes 38c and 40c through which the cam followers 36a of the drive ring 36 pass.

[0025] The cover member 42 is a disk-shaped member having an opening 42a and is attached to the base member 32. In the case of this embodiment, the cover member 42 engages with the base member 32 by snap fit. For this purpose, a plurality of hooks 32c are provided on the base member 32, and recesses 42b that engage with the hooks 32c are formed on the cover member 42. After snap fitting, the cover member 42 is fixed to the base member 32 via a fixing screw 60. Note that a plurality of support holes 42c for supporting the tips of the plurality of support pins 32a of the base member 32 and a plurality of guide grooves 42d for guiding the plurality of cam followers 36a of the drive ring 36 are formed on the cover member 42. When such a cover member 42 is attached to the base member 32, a plurality of aperture vanes 34, a drive ring 36, a first sheet 38, and a second sheet 40 are accommodated in the space defined by the cover member 42 and the base member 32.

[0026] Supplementary note, as shown in FIG. 8, the drive ring 36 is accommodated in the annular recess 32d of the base member 32. The plurality of aperture vanes 34, the first sheet 38, and the second sheet 40 are not accommodated in the recess 32d, but are arranged between the inner and outer annular surfaces 32e, 32f located inside and outside the annular recess 32d and the cover member 42. Therefore, the plurality of support pins 32a that support the plurality of aperture vanes 34, the first sheet 38, and the second sheet 40 are provided on the outer annular surface 32f.

[0027] Hereinafter, further features of the light shielding unit 30 according to this embodiment will be described.

[0028] FIG. 9 is a diagram for explaining a part of the assembly of the light shielding unit. FIG. 10 is a cross-sectional view of a part of the light shielding unit along the radial direction of the lens barrel. Further, FIG. 11 is a rear view of a part of the light shielding unit with the cover member removed. Furthermore, FIG. 12 is a plan view of the first sheet. And FIG. 13 is a plan view of the second sheet. Note that in FIG. 13, the first sheet 38 is indicated by a dashed line.

[0029] As shown in Fig. 9, the assembly of the light-shielding unit 30 is performed by sequentially assembling a drive ring 36, a first sheet 38, a plurality of aperture blades 34, a second sheet 40, and a cover member 42 to a base member 32. Specifically, first, the drive ring 36 is incorporated into the annular recess 32d of the base member 32.

[0030] Next, the first sheet 38 is moved in the longitudinal direction of the optical axis C and placed on the outer annular surface 32f of the base member 32 such that the plurality of engagement holes 38b of the first sheet 38 pass through the corresponding support pins 32a of the base member 32 and the plurality of long holes 38c pass through the corresponding cam followers 36a of the drive ring 36.

[0031] Subsequently, the plurality of aperture blades 34 are placed on the first sheet 38 such that the through holes 34a of the respective aperture blades 34 pass through the corresponding support pins 32a of the base member 32 and the respective cam grooves 34b pass through the corresponding cam followers 36a of the drive ring 36.

[0032] Subsequently, the second sheet 40 is placed on the plurality of aperture blades 34 such that the plurality of engagement holes 40b of the second sheet 40 pass through the corresponding support pins 32a of the base member 32 and the plurality of long holes 40c pass through the corresponding cam followers 36a of the drive ring 36.

[0033] Then, the cover member 42 is attached to the base member 32. In the case of the present embodiment, as shown in Fig. 10, the cover member 42 is attached to the base member 32 by a snap fit, that is, by engaging a plurality of hooks 32c provided on the base member 32 with corresponding recesses 42b provided on the cover member 42. After being attached, the cover member 42 is fixed to the base member 32 via fixing screws 60.

[0034] When the cover member 42 is attached to the base member 32, as shown in FIG. 10, an annular space, the blade chamber BR, is formed between the cover member 42 and the base member 32. That is, the cover member 42 and the base member 32 cooperate to define the blade chamber BR.

[0035] A plurality of throttle blades 34 are stored in the blade chamber BR. As shown in FIGS. 4 and 10, when the light shielding unit 30 is open, substantially the entire plurality of throttle blades 34 are stored in the blade chamber BR.

[0036] Also, in the blade chamber BR, there are a first sheet 38 and a second sheet 40. Specifically, in the blade chamber BR, the first sheet 38 is disposed between the base member 32 and the plurality of throttle blades 34, and the second sheet 40 is disposed between the plurality of throttle blades 34 and the cover member 42.

[0037] Also, the first sheet 38 covers a through hole 32g of the base member 32 that communicates with the blade chamber BR. One opening of this through hole 32g opens in the blade chamber BR. The other opening of the through hole 32g opens on the front surface of the base member 32 as shown in FIG. 7. Therefore, there is a risk that foreign matter in the internal space in front of the light shielding unit 30 in the lens barrel 10 may enter the blade chamber BR through the through hole 32g. In order to suppress the entry of the foreign matter into the blade chamber BR, a part of the first sheet 38 covers the opening of the through hole 32g on the blade chamber BR side.

[0038] Note that this through-hole 32g does not substantially function during the use of the lens barrel 10. However, this through-hole 32g is inevitably formed when creating the hook 32c. Specifically, as shown in FIGS. 10 and 11, the through-hole 32g overlaps with the tip 32c1 of the hook 32c in the extending direction of the optical axis C (Z-axis direction). The reason is that in the case of this embodiment, the base member 32 is formed using a mold. To mold the base member 32, a mold divided in the front-rear direction (the extending direction of the optical axis C) of the light-shielding unit 30 is used. In the case of such a mold, the portion of the mold that forms the tip 32c1 of the hook 32c shown in FIG. 10 inevitably forms a through-hole 32g in the base member 32 of the molded product. That is, during molding, there is a portion of the mold that forms the tip 32c1 of the hook 32c within the through-hole 32g. Therefore, this through-hole 32g exists despite not functioning during the use of the lens barrel 10 in order for the base member 32 and the cover member 42 to snap fit.

[0039] The first sheet 38 needs to be placed on the plurality of aperture vanes 34 on the base member 32 beyond the tip 32c1 of the hook 32c in order to cover such a through-hole 32g. For this purpose, the first sheet 38 is made of a deformable material.

[0040] In the case of this embodiment, since the first sheet 38 covers the through-hole 32g, the second sheet 40 does not need to cover the through-hole 32g. Therefore, as shown in FIG. 11, a notch 40d is provided in the portion of the second sheet 40 that overlaps with the tip 32c1 of the hook 32c when viewed in the extending direction of the optical axis C (viewed perpendicular to the drawing plane). That is, when viewed in the extending direction of the optical axis C, the contour of the notch 40d surrounds the tip 32c1 of the hook 32c with a gap. Thereby, when the second sheet 40 is overlapped with the plurality of aperture vanes 34 during the production of the light-shielding unit 30, contact between the second sheet 40 and the tip 32c1 of the hook 32c can be avoided. As a result, since it is not necessary to deform the second sheet 40 to go beyond the tip 32c1 of the hook 32c, the assemblability of the second sheet 40 to the base member 32 is improved.

[0041] Also, as shown in FIGS. 12 and 13, the shapes of the first and second sheets 38 and 40 are similar to each other. Also, since the first and second sheets 38 and 40 have light-shielding properties, they are both dark in color, for example, black. Therefore, there is a possibility that an operator may mistakenly attach the second sheet 40 to the base member 32 instead of the first sheet 38. As shown in FIG. 12, a notch such as the notch 40d of the second sheet 40 is not provided in the first sheet 38. Therefore, the first sheet 38 and the second sheet 40 can be distinguished by the presence or absence of the notch. In the case of the present embodiment, in order to make the distinction easier, as shown in FIG. 13, the first sheet 38 includes a portion 38d that does not overlap with a protruding portion 40e provided on the outer periphery of the second sheet 40 when the first sheet 38 and the second sheet 40 overlap in the extending direction of the optical axis C. By this portion 38d, it is possible to easily confirm that the first sheet 38 has already been attached to the base member 32 immediately before attaching the cover member 42 to the base member 32. That is, when this portion 38d cannot be visually recognized, the first sheet 38 has not been attached to the base member 32.

[0042] According to the embodiment as described above, in a lens barrel in which a through hole communicating with a vane chamber for storing a plurality of aperture vanes exists in a member defining the vane chamber, it is possible to suppress the intrusion of foreign matter into the vane chamber through the through hole.

[0043] As described above, the embodiments of the present disclosure have been described by way of the above-described embodiments, but the embodiments of the present disclosure are not limited to the above-described embodiments.

[0044] For example, in the case of the above-described embodiment, the through hole 32g of the base member 32 covered by the first sheet 38 is inevitably formed by the molding of the hook 32c. However, the through holes communicating with the blade chamber BR and covered by the first sheet 38 are not limited to the through hole 32g. That is, the through holes communicating with the blade chamber BR that need to be covered by the first sheet 38 may be through holes that do not function during the use of the lens barrel 10 but are used during manufacturing, inspection, and maintenance.

[0045] That is, the light-shielding unit according to the embodiment of the present disclosure broadly includes a plurality of aperture blades, a base member that rotatably supports each of the plurality of aperture blades, a cover member that is attached to the base member and defines a blade chamber that stores the plurality of aperture blades in cooperation with the base member, and an annular first sheet that is disposed between the base member and the plurality of aperture blades in the blade chamber and on which the plurality of aperture blades slide. The base member is provided with a through hole communicating with the blade chamber, and the first sheet covers the through hole, which is the light-shielding unit.

[0046] As described above, the above-described embodiment has been described as an example of the technology in the present disclosure. For this purpose, drawings and detailed descriptions have been provided. Therefore, among the components described in the drawings and the detailed description, there may be not only the components essential for solving the problem but also the components not essential for solving the problem for the purpose of exemplifying the above-described technology. Therefore, just because those non-essential components are described in the drawings or the detailed description, it should not be immediately determined that those non-essential components are essential.

[0047] In addition, since the above-described embodiment is for exemplifying the technology in the present disclosure, various changes, replacements, additions, omissions, etc. can be made within the scope of the claims or their equivalents.

Industrial Applicability

[0048] The present disclosure is applicable to a lens barrel including a light-shielding unit.

Description of Symbols

[0049] 32 Base member 32g Through-hole 34 Throttle blade 38 First sheet 42 Cover member BR Blade chamber

Claims

1. A plurality of aperture vanes, a base member that rotatably supports each of the plurality of aperture vanes, a cover member attached to the base member and defining a vane chamber that cooperates with the base member to store the plurality of aperture vanes, and an annular first sheet disposed between the base member and the plurality of aperture vanes in the vane chamber, on which the plurality of aperture vanes slide. The base member has a through hole that communicates with the vane chamber, and the first sheet is a light-shielding unit that covers the through hole.

2. The base member includes a hook, the cover member includes a recess that snap-fits with the hook, and the through hole overlaps the tip of the hook when viewed in the direction of the optical axis extension. The light-shielding unit according to claim 1.

3. The light-shielding unit further includes an annular second sheet disposed between the plurality of aperture vanes and the cover member, on which the plurality of aperture vanes slide. The second sheet has a notch in a portion that overlaps the tip of the hook when viewed in the direction of the optical axis extension. The light-shielding unit according to claim 2.

4. The first sheet includes a portion that does not overlap the second sheet when the first sheet and the second sheet overlap when viewed in the direction of the optical axis extension. The light-shielding unit according to claim 3.

5. The light-shielding unit is provided in a lens barrel, and the through hole diameter of the second sheet is the aperture of the lens barrel. The light-shielding unit according to claim 3.

6. At least one lens, and a lens barrel having the light-shielding unit according to any one of claims 1 to 5.

Images