JP2018025575A - Accessory for lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical accessory comprising an accessory fitting frame of high flexibility.SOLUTION: An optical accessory mounted at a subject-side tip of a lens device provided with a positioning groove connecting with nearby the subject-side tip over the entire circumference comprises: an accessory fitting frame fitted in at least a lens device and an elastic member molded in a substantially channel shape; an operation member for fixing the lens device and optical accessory; and a movable member moving as the operation member is operated. The elastic member is provided with an engagement part at both ends, and the accessory fitting frame is provided with a storage groove for accommodating the elastic member, a fixed end that one engagement part of the elastic member engages, and a cut that the other engagement part of the elastic member pierces through. The engagement part of the elastic member engages the movable member through the cut, and as the operation member is operated in a clamping direction, a channel-shaped part of the elastic member decreases in diameter, so that the elastic member while fitted in the positioning groove clamps the subject-side tip part of the lens device.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lens accessory, and more particularly to an optical accessory attached to a subject side of a lens.

  In order to protect the lens device of an imaging device such as a camera or a video camera from being damaged when the lens device is placed, the subject side end of the lens barrel is generally protruded toward the subject side from the front lens. ing.

  Conventionally, an optical accessory that is attached to the front (subject side) of such a lens device is commercially available. For example, a lens hood (Patent Document 1), an optical filter, a teleconverter, a wide converter, a wide attachment, a fish eye attachment, a close-up lens, and the like are known.

  The attachment of the optical accessory to the lens device will be described below by taking an example of attachment of the lens hood to the lens device. The inner diameter of the accessory mounting frame and the outer diameter of the portion of the lens device where the optical accessory is mounted are substantially the same diameter. When mounting, the accessory mounting frame is first inserted from the front of the lens device. Next, when the rear end of the accessory mounting frame comes into contact with the flange portion of the lens device outer diameter portion, the lock screw of the accessory mounting frame is tightened. An arcuate locking member having one end fixed to the accessory mounting frame is disposed on the inner diameter side of the accessory mounting frame.

  When the lock screw is tightened, a part of the locking member that is pressed and elastically deformed engages with a groove provided in the outer diameter portion of the lens device, and a lens hood as an optical accessory can be fixed to the lens device. Patent Document 2 introduces a structure in which an optical accessory is attached to a lens by providing a bayonet engaging portion on the lens barrel and the optical accessory.

Japanese Patent Laid-Open No. 9-211303 JP 2006-84604 A

  However, in the above-mentioned Patent Document 1, there is a description that the lens apparatus is deformed by fixing the optical accessory of the prior art, and the deformation is transmitted to the lens feeding mechanism, so that the operation of the lens apparatus is lowered.

  In order to solve the problem, Patent Document 1 proposes a method in which the accessory mounting portion of the lens apparatus and the lens feeding mechanism are configured as separate members so that deformation due to fixing of the optical accessory is not transmitted to the lens feeding mechanism. doing. However, since it is not an improvement with an optical accessory, when the optical accessory of Patent Document 1 is attached to another lens apparatus to which the technology of Patent Document 1 is not applied, there is a possibility that the operation of the lens apparatus may be lowered. The versatility of accessories cannot be increased.

  Moreover, when providing a bayonet structure like patent document 2, possibility that a lens-barrel will deform | transform by attachment of an optical accessory becomes low. However, since the lens barrel has a special shape, the versatility of the optical accessory may be reduced.

  Therefore, there is a problem of both preventing the deterioration of operability due to the deformation of the lens device caused by the attachment of the optical accessory and enhancing the versatility of the optical accessory.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an optical accessory including a highly versatile accessory mounting frame that does not deteriorate the operability of the lens device.

  In order to achieve the above object, the present invention provides an optical accessory that is attached to a subject-side tip of a lens device in which a positioning groove connected to the entire periphery is provided near the subject-side tip, and the optical accessory is at least an accessory that fits into the lens device. An elastic member comprising an attachment frame, an elastic member molded in a substantially C shape, an operation member for performing an operation for fixing the lens device and the optical accessory, and a movable member that moves by operating the operation member. Engaging portions are provided at both ends, the accessory mounting frame has a storage groove for accommodating the elastic member, a fixed end to which one engaging portion of the elastic member is engaged, and the other engaging portion of the elastic member. A notch that penetrates is provided, and the engaging portion of the elastic member engages with the movable member through the notch, and when the operating member is operated in the tightening direction, the diameter of the C-shaped portion of the elastic member is reduced. And, the elastic member, characterized in that tightening the subject side tip of the lens apparatus while fitted into the positioning groove.

  ADVANTAGE OF THE INVENTION According to this invention, an optical accessory provided with the versatile accessory mounting frame which does not reduce the operativity of a lens apparatus can be provided.

The figure which shows the typical structure of the optical accessory of this invention Sectional drawing of the typical structure of the accessory mounting frame of this invention The figure which shows a state when a lens is inserted in the accessory attachment frame of this invention Sectional drawing of a part of radial direction when a lens is inserted into the accessory mounting frame of the present invention The figure which shows the state when the accessory mounting frame and lens of this invention are fixed. Partial sectional view of the radial direction when the accessory mounting frame and the lens of the present invention are fixed Partial cross-sectional view in radial direction showing additional effects of the present invention

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing a configuration of an optical accessory according to an embodiment of the present invention.

[Example]
Hereinafter, an optical accessory according to an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows a typical configuration of the present invention. A lens hood 2 is attached to the accessory mounting frame 1 as an optical accessory. A storage groove 1 b is provided in a part of the inner diameter 1 a of the accessory mounting frame 1. The elastic member 3 is formed by forming a wire spring material having a circular cross section into a substantially C shape, and engaging portions 3a and 3b are provided at both ends so as to be bent toward the outside of the C shape portion.

  The operation member 4 is provided with a knob 4a, a screw portion 4b, and an engaging portion 4c. The movable member 5 has a cylindrical shape, and is provided with a female screw 5a having an inner diameter and an engagement hole 5b. Screws 6 and 7 as restricting means are fixed to the accessory mounting frame 1. An outer diameter portion 8 a inserted into the inner diameter 1 a of the accessory mounting frame 1 and a flange portion 8 b against which the accessory mounting frame 1 abuts are provided at the subject-side tip of the lens device 8. The outer diameter portion 8a is provided with a positioning groove 8c having a depth smaller than the diameter of the material of the elastic member 3, and the positioning groove 8c has a shape in which a part of the outer diameter portion 8a is cut out over the entire circumference.

  FIG. 2 shows a typical configuration of the accessory mounting frame of the present invention. By configuring the depth and width of the storage groove 1b to be at least the same as or larger than the cross-sectional diameter of the material of the elastic member 3, the elastic member 3 is stored in the storage groove 1b. Further, the outer diameter of the C-shaped part excluding the engaging part of the elastic member 3 is configured to be at least the same as or larger than the outer diameter of the storage groove 1b of the accessory mounting frame 1. Thereby, the elastic member 3 is assembled without protruding to the inner diameter 1a of the accessory mounting frame 1 in a state in which the elastic member 3 is biased outward with respect to the storage groove 1b.

  The accessory mounting frame 1 is provided with notches 1d and 1f extending from the inner diameter to the outer diameter and extending in the circumferential direction on both sides of the fixed wall 1c. The notches 1d and 1f are provided at positions overlapping the storage groove 1b in the optical axis direction, and the engaging portions 3a and 3b of the elastic member 3 protrude from the notches 1d and 1f to the outer diameter side, respectively. Further, the end portion of the notch 1d is a fixed end 1e and abuts on the engaging portion 3a of the elastic member 3.

  The operation member 4 protrudes the screw part 4b from the hole provided in the fixed wall 1c of the accessory mounting frame 1, and the tip of the screw 6 fixed to the accessory mounting frame 1 is caught by the engaging part 4c. Thereby, the movement of the operation member 4 in the axial direction with respect to the accessory mounting frame 1 is restricted, and only rotation is possible.

  The movable member 5 is configured in a groove 1h on the opposite side across the operation member 4 and the fixed wall 1c, and the female screw 5a provided on the inner diameter is screwed with the screw portion 4b of the operation member 4. Further, the engaging direction 3b of the elastic member 3 is engaged with the engaging hole 5b, whereby the rotation direction of the movable member 5 can be restricted. Accordingly, by operating the knob 4a of the operation member 4, the movable member 5 moves in the groove 1h in the axial direction of the operation member 4. Furthermore, when the tip of the screw 7 fixed to the accessory mounting frame 1 protrudes into the groove 1h, the moving amount of the movable member 5 is limited within a range in which the movable member 5 does not fall off from the operation member 4.

  When the knob 4a is operated in the release direction, the movable member 5 moves upward in FIG. Thereby, the engaging portions 3a and 3b of the elastic member 3 are separated from each other, so that the diameter of the C-shaped portion of the elastic member 3 is increased. When the knob 4a is operated in the tightening direction, the movable member 5 moves downward in FIG. As a result, the engaging portions 3a and 3b of the elastic member 3 are brought closer, so that the diameter of the C-shaped portion of the elastic member 3 is reduced.

  FIG. 3 shows a state in which the lens device 8 is inserted into the optical accessory of the present invention. When the knob 4a of the operation member 4 is operated in the release direction, the lens device 8 can be inserted into the accessory mounting frame 1. At this time, a gap X1 is opened between the movable member 5 and the fixed wall 1c.

  FIG. 4 shows a part of the radial cross section at that time. Since the elastic member 3 is stored in the storage groove 1b, the accessory mounting frame 1 and the outer diameter portion 8a at the tip of the lens device 8 are not caught, and the accessory mounting frame 1 and the flange portion 8b are inserted to a position where they abut. The

  FIG. 5 shows a state in which the optical accessory of the present invention and the lens device 8 are fixed. When the knob 4a of the operation member 4 is operated in the tightening direction, the movable member 5 is moved downward in the figure by screw feed, and the gap between the movable member 5 and the fixed wall 1c becomes X2.

  FIG. 6 shows a part of the radial cross section at that time. As the movable member 3 moves, the engaging portion 3b approaches the engaging portion 3a, and the diameter of the C-shaped portion of the elastic member 3 is reduced. The elastic member 3 has a diameter smaller than the inner diameter of the accessory mounting frame 1 and fits into a positioning groove 8 c provided in the lens device 8. When the knob 4a is further operated, the elastic member 3 contacts the bottom surface of the positioning groove 8c, and the accessory mounting frame 1 and the lens device 8 are fixed by tightening the bottom surface of the positioning groove 8c.

  As described above, in the optical accessory of the present invention, the C-shaped part of the elastic member is entirely deformed by the tightening operation to reduce the diameter and contact the lens device. Is not added. For this reason, the subject-side tip of the lens device is unlikely to be deformed, and it is possible to prevent a decrease in operability due to the deformation being transmitted to the lens feeding mechanism. In addition, since it is not necessary to give the lens device a special structure or strength, an optical accessory can be used without selecting a lens type if the mounting diameter is suitable.

  Further, when the knob 4a of the operation member 4 is operated in the tightening direction and the inner diameter of the C-shaped portion of the elastic member 3 becomes smaller than the outer diameter of the outer diameter portion 8a, it is from when it hits the bottom of the positioning groove 8c. In the meantime, the elastic member 3 is caught by the walls in the optical axis direction of both the storage groove 1b and the positioning groove 8c. Therefore, even if the optical accessory moves in the optical axis direction with the knob 4a not tightened, the optical accessory can be prevented from dropping from the lens device.

  Further, as shown in FIG. 7, a slope 8d is provided in the positioning groove 8c, the depth of the positioning groove 8c is made shallower than the radius of the material of the elastic member 3, and the elastic member 3 is attached to the wall 1i of the storage groove 1b and the slope when tightening. A force is generated in the direction of arrow Y by adopting a configuration in contact with 8d. Since the accessory mounting frame 1 and the flange portion 8b come into contact with each other, the accessory mounting frame 1 is pressed toward the flange portion 8b. Thereby, it becomes possible to stabilize the position of the lens device 8 of the accessory mounting frame 1 in the optical axis direction simultaneously with the fixing.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

  The present invention relates to a lens accessory, and is particularly suitable for an optical accessory attached to a subject side of a lens.

1: Accessory mounting frame 1b: Storage groove 1e: Fixed end 1f: Notch 2: Lens hood (optical accessory)
3: Elastic members 3a, 3b: Engaging portion 4: Operating member 5: Movable member 8: Lens device 8a: Outer diameter portion 8c: Positioning groove

Claims (3)

  In an optical accessory to be mounted on the subject-side tip of a lens apparatus in which a positioning groove connected to the entire periphery is provided near the subject-side tip, the optical accessory is molded into at least an accessory mounting frame that fits into the lens device and a C-shape. An elastic member, an operation member that performs an operation for fixing the lens device and the optical accessory, and a movable member that moves by operating the operation member. The accessory mounting frame is provided with a storage groove for receiving the elastic member, a fixed end with which one engaging portion of the elastic member is engaged, and a cut through which the other engaging portion of the elastic member is passed. When the notch is provided, the engaging portion of the elastic member engages with the movable member through the notch, and the operating member is operated in the tightening direction, the elastic member The optical diameter of the C-section is reduced in wood, the elastic member is characterized in that tightening the subject side end portion of the lens apparatus while fitted into the positioning groove accessory.   When the operating member is operated in the release direction, the elastic member expands the diameter of the C-shaped part, the inner diameter of the C-shaped part becomes larger than the outer diameter of the subject-side tip of the lens device, and the operating member is tightened in the tightening direction. 2. The optical accessory according to claim 1, wherein the diameter of the C-shaped portion is reduced when operated to reduce an inner diameter of the C-shaped portion smaller than an outer diameter of the positioning groove at a subject-side tip of the lens device. .   The elastic member is a wire spring having a circular cross section having a radius larger than the depth of the positioning groove, and the wall surface in the optical axis direction of the positioning groove is a tapered surface, and the lens device and the optical accessory are fixed. The optical accessory according to claim 1, wherein the elastic member contacts the tapered surface and the wall surface of the positioning groove simultaneously.