Lens device and imaging device

Abstract

To provide a lens device which is advantageous in terms of the smooth movement of a lens group, even when an accessory is attached for instance.SOLUTION: The lens device includes a first cylindrical member which holds the lens group and in which a male screw is formed on the outer peripheral part, a second cylindrical member in which a female screw to be engaged with the male screw is formed on the inner peripheral part, an operation member which is fitted to the outside of the second cylindrical member and is rotatable around the shaft of the second cylindrical member, and a connection member which connects the first cylindrical member and the operation member and transmits the rotation of the operation member around the shaft to the first cylindrical member. In the second cylindrical member, a hole penetrating in a radial direction is formed in a part where the female screw is not formed. The connection member is inserted into the hole, to connect the first cylindrical member and the operation member.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a lens device and an imaging device.

Background Art

[0002] As a lens device having an inner focus mechanism, there is known one having a lens group that moves along an optical axis by a helicoid screw formed on an inner peripheral portion of a fixed cylinder, an operation ring provided on an outer peripheral portion of the fixed cylinder, and a connecting member that connects the operation ring and the lens group to each other. The lens group moves along the optical axis by rotating the operation ring around the optical axis.

[0003] In order to avoid interference between the connecting member and the fixed cylinder when moving the lens group by rotation of the operation ring, a long hole is formed in the fixed cylinder, and the connecting member is inserted into the long hole to connect the operation ring and the lens group to each other.

[0004] FIG. 2 of Patent Document 1 discloses the positional relationship among the helicoid screw of the fixed cylinder, the lens group, the operation ring, and the connecting member described above. In Patent Document 1, the connecting member has a pin shape, is provided on the lens group, and engages with a guide hole of the operation ring. The fixed cylinder is formed with a long hole penetrating the helicoid screw in order to avoid interference with the connecting member. When an accessory such as a hood is attached to the tip of the fixed cylinder, the fixed cylinder is divided to reduce the strain transmitted to the helicoid screw in order to reduce the influence of the strain of the helicoid screw on the operation of the focus mechanism.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] When an accessory is fastened to an accessory fixing frame with screws in the lens barrel of Patent Document 1, the axial force (tightening force) of the screws reaches, for example, several tens to several hundreds of kgf, causing the accessory fixing frame to deform. Then, the gap between the accessory and the accessory fixing frame is filled, and the deformation force on the accessory fixing frame is transmitted to the fixed cylinder, distorting the helicoid screw and possibly affecting the operation of the focusing mechanism. Also, since the fixed cylinder has a long hole for passing (inserting) a connecting member formed in the helicoid screw, the strength (rigidity) around the long hole is low, making the helicoid screw prone to distortion. An object of the present invention is to provide a lens device that is advantageous in terms of smooth movement of a lens group even when an accessory is attached, for example.

Means for Solving the Problems

[0007] To achieve the above object, a lens device of the present invention includes a first cylindrical member that holds a lens group and has a male screw formed on an outer peripheral portion, a second cylindrical member that has a female screw formed on an inner peripheral portion and engages with the male screw, an operation member that fits outside the second cylindrical member and is rotatable around the axis of the second cylindrical member, and a connecting member that connects the first cylindrical member and the operation member and transmits rotation of the operation member around the axis to the first cylindrical member. The second cylindrical member On the object side of the portion where the female screw is formed, there is a mounting portion for mounting an accessory. has a hole formed therethrough in the radial direction at a portion where the female screw is not formed. The connecting member is fixed to one of the first cylindrical member and the operation member, slidably engages with a groove formed in the other of the first cylindrical member and the operation member, and is inserted into the hole to connect the first cylindrical member and the operation member. , on the image side of the portion where the female screw is formed. is characterized by the above.

Effects of the Invention

[0008] According to the present invention, for example, a lens device that is advantageous in terms of smooth movement of a lens group can be provided even when an accessory is attached.

Brief Description of the Drawings

[0009] [[Figure 1]]Cross-sectional view of the lens barrel in Embodiment 1 of the present invention [[Figure 2]] Detailed view of the lens barrel in Embodiment 1 of the present invention [[Figure 3]] Detailed view of the lens barrel in Embodiment 2 of the present invention

Mode for Carrying Out the Invention

[0010] Hereinafter, preferred embodiments of the present invention will be described in detail based on the accompanying drawings.

Example

[0011] Hereinafter, with reference to FIG. 1, the lens barrel 1 according to the first embodiment of the present invention will be described. FIG. 1 shows an overall view of the lens barrel in this embodiment.

[0012] The lens barrel 1 of this embodiment has a mechanism for a user to focus by moving a moving cylinder (first cylindrical member) 2 having a focus group in the optical axis direction by a helicoid structure.

[0013] A plurality of lenses 3 (3a, 3b, 3c, 3d) are provided in the lens barrel 1. From FIG. 1, the lens 3a of the front fixed group is fixed to a fixed cylinder (second cylindrical member) 4, the focus lens (focus lens group) 3b is supported by the moving cylinder 2, and the lenses 3c and 3d of the relay group are fixed to the fixed cylinder 4. The plurality of lenses 3 are fixed by fastening a presser ring to a screw portion (not shown) provided on the fixed cylinder or the moving cylinder. For example, the lens 3a is fastened and fixed by screwing the screw portion of the presser ring 5 into the screw portion 5a provided on the moving cylinder 2. Here, the case where the focus lens 3b is held by the moving cylinder 2 will be exemplified and described, but the present invention is not limited to this configuration. The lens group held by the moving cylinder 2 shall include the case of at least one single lens or cemented lens.

[0014] The fixed cylinder 4 is formed with a female helical screw (female screw) 4a having a plurality of threads on its inner peripheral portion, which is screwed with a male helical screw (male screw) 2a of the moving cylinder 2 described later. Further, an accessory fixing cylinder (mounting portion, third cylindrical member) 12 is screwed and fixed to the tip of the fixed cylinder 4.

[0015] An accessory (lens accessory) 6 such as a lens hood, a converter lens (teleconverter lens, wide converter lens), or a filter is provided with a screw portion 6a having an axial direction in a direction orthogonal to the optical axis, and an accessory screw 7 is screwed into the screw portion. The accessory screw 7 has a pin shape with a knurled portion on its outermost peripheral portion. The user can fix the accessory 6 to the accessory fixing cylinder 12 by pinching and rotating the knurled portion with a finger. FIG. 1 shows a state in which the accessory 6 is inserted into the accessory fixing cylinder 12 from the object side end and fixed to the accessory fixing cylinder 12, where the tip of the screw portion of the accessory screw 7 abuts against the accessory fixing cylinder 12, and the accessory 6 is fixed and mounted on the accessory fixing cylinder 12. At this time, a load F acts in the axial direction of the accessory screw 7 at the location where the accessory screw 7 abuts.

[0016] As shown in FIG. 2, the moving cylinder 2 has a substantially cylindrical shape, holds a lens 3 and a pressing ring 5 on the inner peripheral side, and has a male helicoid screw 2a with a plurality of threads formed on the outer side. Further, the moving cylinder 2 is provided with a screw portion 2b in a direction orthogonal to the optical axis direction, and a pin-shaped connecting member 8 is fastened to the screw portion 2b. The connecting member 8 slidably engages with a straight groove (groove portion) 9a of an operation ring (operation member) 9 described later. Due to the configuration of the connecting member 8 and the straight groove 9a, relative rotation of the moving cylinder 2 and the operation ring 9 about the axial direction is restricted. That is, the connecting member 8 transmits the rotation of the operation ring 9 around the axis to the moving cylinder 2. When the moving cylinder 2 moves in the optical axis direction, the connecting member 8 fastened to the moving cylinder 2 also rotates by rotating along the thread of the helicoid screw. The fixed cylinder 4 is provided with an inclined groove (hole portion) 4b through which the connecting member 8 centered on the optical axis is inserted in order to avoid interference accompanying the rotation of the connecting member 8. The inclined groove 4b is provided at a location different in the optical axis direction (the image side of the location where the female helicoid screw 4a is provided) independent of the location where the female helicoid screw 4a of the fixed cylinder 4 is provided.

[0017] The operation ring 9 has a substantially cylindrical shape, and the inner peripheral side slides with the sliding surface with the fixed cylinder 4 and is rotatable about the optical axis. Further, the movement of the operation ring 9 in the optical axis direction is restricted by the restricting surface 4c of the fixed cylinder 4 and the operation ring presser 10 fixed to the fixed cylinder 4 with screws. The operation ring 9 is provided with a straight groove 9a extending parallel to the optical axis direction, and the straight groove 9a penetrates the operation ring 9 in the radial direction centered on the optical axis. The connecting member 8 slidably engages with the straight groove 9a.

[0018] An operation ring rubber 11 is fitted on the outer peripheral surface of the operation ring 9. The operation ring rubber 11 has a function of preventing slipping when the user rotates the operation ring 9.

[0019] With the above configuration, even when the accessory screw 7 is tightly tightened and a deformation force acts from the accessory fixing cylinder 12 to the fixing cylinder 4, the lens barrel 1 has a cylindrical shape with an inclined groove (hole portion) 4b formed at a position where the female helicoid screw 4a is not formed. Therefore, the amount of distortion of the female helicoid screw 4a can be minimized. When the amount of distortion of the female helicoid screw 4a is reduced, the torque unevenness when the operation ring 9 is rotated is reduced, improving the operability for the user. Also, the amount of play between the female helicoid screw 4a and the male helicoid screw 2a can be reduced, reducing the amount of eccentricity and tilt of the moving cylinder 2 from the optical axis, and suppressing fluctuations in optical performance.

Embodiment

[0020] Hereinafter, with reference to FIG. 3, the lens barrel 1 according to the second embodiment of the present invention will be described. The same parts as those in the above-described first embodiment are omitted.

[0021] As shown in FIG. 3, the moving cylinder 20 has a substantially cylindrical shape, holds the lens 3 and the presser ring 5 on the inner peripheral side, and has a male helicoid screw 20a with a plurality of threads formed on the outer peripheral side. Also, the moving cylinder 20 is provided with a straight groove (groove portion) 20b parallel to the optical axis direction, and the tip of a connecting member 21 described later is fitted therein.

[0022] The fixed cylinder 22 has a female helicoid screw 22a with a plurality of threads formed on the inner peripheral side, which meshes with the male helicoid screw 20a of the moving cylinder 20 described later.

[0023] The operation ring 23 has a substantially cylindrical shape, and its inner peripheral side slides on the sliding surface with the fixed cylinder 22 and can rotate about the optical axis. A threaded portion 23a is provided in the operation ring 23 in a direction perpendicular to the optical axis, and the connecting member 21 is screwed and fixed therein. The connecting member 21 has a pin shape, and its tip is slidably engaged with the straight groove 20b of the moving cylinder 20. Due to the configuration of the connecting member 21 and the straight groove 20b, the relative rotation of the moving cylinder 20 and the operation ring 23 about the axial direction is restricted. When the operation ring 23 rotates, the connecting member 21 fastened to the operation ring 23 also rotates. The fixed cylinder 22 is provided with a long hole portion 22b through which the connecting member 21 is inserted in order to avoid interference associated with the rotation of the connecting member 21. The long hole portion 22b is provided at a different location independent of the location where the female helicoid screw 22a is provided.

[0024] With the above configuration, even when the accessory screw 7 is strongly tightened and a deformation force acts on the fixed cylinder 4 from the accessory fixing cylinder 12 in the lens barrel 1, since the female helicoid screw 22a has a cylindrical shape without a hole portion, the amount of distortion of the female helicoid screw 22a can be minimized. When the amount of distortion of the female helicoid screw 22a is reduced, the torque unevenness when rotating the operation ring 23 is reduced, improving the operability for the user. Also, the amount of play between the female helicoid screw 22a and the male helicoid screw 20a can be reduced, and the amount of eccentricity and tilting of the moving cylinder 20 from the optical axis can be reduced, thereby suppressing fluctuations in optical performance. In addition, in this embodiment, although it has been shown that the connecting member 8 and the connecting member 21 have a pin shape, the connecting member may not have a pin shape and may be a rectangular parallelepiped shape or an L-shaped shape formed of sheet metal or the like.

[0025] Also, by configuring a lens device having the lens barrel of the present invention and an imaging device having an imaging element disposed on the image plane of the lens device, an imaging device having the effects of the present invention can be realized. As described above, the preferred embodiments of the present invention have been described, but the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist thereof.

Explanation of Reference Numerals

[0026] 2: Moving cylinder 2a: Male helicoid screw (male screw) 3b: Lens 4: Fixed cylinder 4a: Female helicoid screw (female screw) 8: Connecting member 9: Operating ring

Claims

1. A first cylindrical member that holds a lens group and has a male screw formed on its outer peripheral portion, a second cylindrical member having a female screw formed on its inner peripheral portion that engages with the male screw, an operating member that fits outside the second cylindrical member and is rotatable around the axis of the second cylindrical member, a connecting member that connects the first cylindrical member and the operating member and transmits the rotation of the operating member around the axis to the first cylindrical member, characterized by comprising: the second cylindrical member has a mounting portion for mounting an accessory on the object side of the portion where the female screw is formed, in the portion where the female screw is not formed, a hole penetrating in the radial direction is formed on the image side of the portion where the female screw is formed, the connecting member is fixed to one of the first cylindrical member and the operating member, slidably engages with a groove formed in the other of the first cylindrical member and the operating member, and is inserted into the hole to connect the first cylindrical member and the operating member. A lens device characterized by this.

2. The lens device according to claim 1, wherein the first cylindrical member moves along the axis by the rotation of the operating member.

3. The lens device according to claim 2, wherein the connecting member is fixed to the first cylindrical member and slidably engages with a groove formed in the inner peripheral portion of the operating member.

4. The lens device according to claim 2, wherein the connecting member is fixed to the operating member and slidably engages with a groove formed in the outer peripheral portion of the first cylindrical member.

5. The first cylindrical member moves along the axis by the rotation of the operating member, the lens barrel according to claim 1, characterized in that the hole is provided near the female screw.

6. The lens device according to any one of claims 1 to 5, wherein the mounting portion includes a third cylindrical member fixed to the second cylindrical member.

7. The lens device according to any one of claims 1 to 6, wherein the first cylindrical member holds a focus lens group.

8. The accessory mounted on the mounting portion includes at least one of a teleconverter, a wide converter, a lens hood, and a filter. The lens device according to any one of claims 1 to 7, characterized by this.

9. The lens device according to any one of claims 1 to 8, and An imaging device comprising an imaging element that captures an image formed by the lens device.

Images