JP2010008722A - Lens barrel and camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily adjust frictional load imparted to a moving barrel. <P>SOLUTION: The lens barrel includes: the moving barrel (3) movably supported in a fixed barrel (6) and serving for drive of a moving lens group holding barrel (4) held by the fixed barrel (6); a frictional load generation member (11) attached to either the fixed barrel (6) or the moving barrel (3) and coming into contact with the other, so as to impart moving resistance to the moving barrel (3); a first regulation means (15) regulating the movement of the moving barrel (3) within a first range; a second regulation means (8) regulating the moving barrel (3) within a second range outside the first range when releasing the first regulation means (15); and a contact releasing means (30) releasing contact of the frictional load generation member (11) with either the fixed barrel (6) or the moving barrel (3) when the moving barrel is in the second range. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lens barrel and a camera.

Conventionally, an encoder that detects the position of the focus lens group holding member is used to prevent the focus lens group holding member from being shifted from the normal position by rotating the focus drive ring via the cam follower when the zoom cam ring rotates. A plate spring that gives a frictional force to a fixed cylinder is known. The magnitude of the friction force is adjusted by changing the bending amount of the leaf spring.
JP 11-337804 A

  In order to adjust the frictional force with the lens barrel described in the above publication, it is necessary to remove the encoder from the lens barrel, adjust the bending amount of the leaf spring, and then attach it to the barrel again. There is a problem that it takes a lot of time to adjust the frictional force.

  An object of the present invention is to make it possible to easily adjust a friction load applied to a moving cylinder.

  In order to solve the above-mentioned problems, a first aspect of the present invention is directed to a movable cylinder that is supported by a fixed cylinder so as to be movable, and that is used to drive a movable lens group holding cylinder that is held by the fixed cylinder, the fixed cylinder, A friction load generating member attached to any one of the movable cylinders and contacting the other, thereby imparting a movement resistance to the movable cylinder; and a first regulating means for regulating the movement of the movable cylinder to a first range; A second restricting means for restricting the movable cylinder to a second range outside the first range when the first restricting means is released; and a fixed cylinder when the movable cylinder is in the second range; Contact release means for releasing contact of the frictional load generating member with any one of the movable cylinders is provided.

  According to a second aspect of the present invention, in the lens barrel according to the first aspect, the friction load generating member is a leaf spring, and the contact release means is the friction load of one of the fixed cylinder and the movable cylinder. It is the level | step-difference part provided in the cylinder which a generation | occurrence | production member contacts.

  According to a third aspect of the present invention, in the lens barrel according to the first or second aspect, the lens barrel includes a position detection member used for detecting a position of the movable lens group holding cylinder, and the position detection member and the friction load generation member Are integrally formed.

  According to a fourth aspect of the present invention, in the lens barrel according to the third aspect, the position detection member is a brush and an encoder member made of a metal plate, and the contact between the brush and the encoder member is also in the second range. It is characterized by not being released.

  A fifth aspect of the present invention is a camera including the lens barrel according to any one of the first to fourth aspects.

  According to the present invention, the frictional load applied to the movable cylinder can be easily adjusted.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a conceptual diagram showing a cross section of a lens barrel according to an embodiment of the present invention.

  The lens barrel 100 is an interchangeable lens barrel that is detachably attached to the camera body 50, and includes a fixed lens group 12, a fixed lens holding frame 25, a filter ring 19, an MF ring 1, a moving lens group 13, and a moving lens group. A holding frame 4, a diaphragm unit 40, a fixed cylinder 6, a gear cylinder (moving cylinder) 3, an encoder (position detection member) 9, and the like are provided.

  The fixed lens group 12 and the moving lens group 13 form an imaging optical system that guides subject light to an imaging unit (not shown) built in the camera body 50.

  The fixed lens group 12 is fixed to the end of the fixed cylinder 6 on the subject side in the optical axis direction by using a fixed lens holding frame 25. The fixed lens holding frame 25 is a frame body that holds the fixed lens group 12, and has an annular shape as a whole. The fixed lens holding frame 25 includes a first lens chamber 22 and a second lens chamber 23.

  The fixed lens group 12 includes lenses 12a, 12b, and 12c. The lens (first lens group) 12 a is held in the first lens chamber 22, and the lenses (second lens group) 12 b and 12 c are held in the second lens chamber 23. The first lens chamber 22 is fixed to the second lens chamber 23 by screws c.

  The second lens chamber 23 is fixed to the fixed cylinder 6 by screws b.

  The filter ring 19 is a cylinder having a female thread for attaching a filter and a hood (not shown) to the lens barrel 100, and the overall shape thereof is an annular shape. The MF ring 1 is attached to the outer peripheral surface of the filter ring 19. The MF ring 1 is connected to the gear cylinder 3 via a gear group (not shown) including a gear shaft 1A and a gear 2.

  The gear cylinder 3 that meshes with the gear 2 mechanically engages with the cam ring 5, and transmits the output of an actuator (not shown) and the rotational force of the MF ring 1 to the cam ring 5. The cam ring 5 is mechanically engaged with the moving lens group holding frame 4. The gear cylinder 3 and the cam ring 5 rotate around the same central axis O.

  The encoder 9 detects the position of the moving lens group holding frame 4, and includes an encoder brush 10, an FPC 9 a, and an encoder base (second regulating means) 8.

  An encoder brush base metal 32 is fixed to the gear cylinder 3 by a screw d. The encoder brush 10 made of a metal plate is attached to the encoder brush base metal 32 with a screw (not shown) so as to come into contact with the FPC 9a of the encoder 9 with a predetermined pressure. The encoder brush 10 and the leaf spring (friction load generating member) 11 that contacts the encoder base 8 are integrally formed. The leaf spring 11 is in contact with the encoder base 8 to give a frictional resistance to the gear cylinder 3.

  The moving lens group holding frame 4 is a frame body that holds the moving lens group 13, and the overall shape thereof is an annular shape. The moving lens group holding frame 4 includes a first lens chamber 17 and a second lens chamber 27.

  The moving lens group 13 is disposed closer to the camera body side than the fixed lens group 12 and includes lenses 13a, 13b, 13c, and 13d. The lenses 13 a, 13 b, and 13 c are held in the first lens chamber 17, and the lens 13 d is held in the second lens chamber 27.

  The moving lens group 13 moves back and forth in the optical axis direction by the rotation of the MF ring 1. By moving the moving lens group 13 back and forth in the optical axis direction, the in-focus state of the photographic optical system can be adjusted, for example, to focus on the subject. The lens barrel 100 includes an actuator (not shown) that drives the moving lens group 13 in the optical axis direction. For example, the lens barrel 100 emits light to the moving lens group 13 in accordance with an autofocus instruction signal transmitted from the camera body 50. It also has an autofocus function that automatically advances and retracts in the axial direction to focus automatically.

  The aperture unit 40 adjusts the amount of subject light passing through the photographing optical system formed by the fixed lens group 12 and the moving lens group 13, and is arranged between the fixed lens group 12 and the moving lens group 13. ing. The aperture unit 40 includes a known iris diaphragm device having a plurality of aperture blades.

  The fixed cylinder 6 is a cylinder whose movement with respect to the camera body 50 is restricted in a state where the lens barrel 100 is attached to the camera body 50. The fixed cylinder 6 is provided with screws (first regulating means) 15. The gear cylinder 3 comes into contact with the screw 15 and the rotation of the gear cylinder 3 is restricted. An encoder base 8 is attached to the fixed cylinder 6 with screws 7 and 14 (see FIG. 2A).

  An FPC 9a is attached to the encoder base 8 along the circumferential direction.

  Next, the operation of the lens barrel 100 will be described.

  For example, the gear cylinder 3 rotates around the optical axis when the actuator is operated according to an autofocus instruction signal transmitted from the camera body 50 or when the photographer operates the focus operation ring 1 by hand. When the gear cylinder 3 rotates around the optical axis, the cam ring 5 rotates and the moving lens group holding frame 4 moves in the optical axis direction.

  Next, a method for adjusting the frictional force of the leaf spring 11 will be described with reference to FIGS. 2 (a) to 2 (c) and FIG.

  2A to 2C are views for explaining the relationship between the fixed cylinder 6 and the gear cylinder 3, and FIG. 3 is a conceptual diagram showing a cross section taken along line AA of FIG. 2C.

  2A shows a state where the gear cylinder 3 and the encoder brush 10 are rotatable with respect to the fixed cylinder 6. FIG. 2B shows that the gear cylinder 3 abuts the screw 15, and the gear cylinder 3 and 2C shows that the rotation of the encoder brush 10 is restricted. FIG. 2C shows a state in which the screw 15 is removed, the gear cylinder 3 further rotates, and the encoder brush base metal 32 comes into contact with the encoder base 8. Indicates that The movable range of the gear tube 3 when the screw 15 is present is defined as a first range, and the movable range of the gear tube 3 excluding the first range when the screw 15 is removed is defined as a second range.

  As shown in FIG. 2B, the gear cylinder 3 and the encoder brush 10 can be rotated (moved downward in FIG. 2B) until the gear cylinder 3 comes into contact with the screw 15.

  When the screw 15 is removed, the gear cylinder 3 can move to the second range beyond the first range, the encoder brush base metal 32 comes into contact with the convex portion 8a located at one end of the encoder base 8, and the gear cylinder 3 Rotation is regulated.

  A slope 30 is provided at a portion of the convex portion 8 a of the encoder base 8 close to the gear cylinder 3. When the gear cylinder 3 moves in the second range and the encoder brush base metal 32 comes into contact with the encoder base 8, the leaf spring 11 moves away from the encoder base 8 through the inclination 30, and the encoder base 8 and the fixed cylinder 6 are separated from each other. The contact between the leaf spring 11 and the encoder base 8 is released by the step portion. The contact between the encoder brush 10 and the encoder base 8 is not released even in the second range.

  When the contact force of the leaf spring 11 with respect to the fixed cylinder 6 is to be adjusted, the screw 15 is removed, and the gear cylinder 3 and the encoder brush 10 are rotated to the second range beyond the position where the screw 15 is located. When the gear cylinder 3 and the encoder brush 10 are rotated beyond the position where the screw 15 is located (first range), the leaf spring 11 is separated from the encoder base 8, so the bending amount of the leaf spring 11 is adjusted using tweezers or the like. (See FIG. 3). As shown in FIG. 2C, the gear cylinder 3 and the encoder brush 10 can rotate until the encoder brush base metal 32 comes into contact with the convex portion 8 a of the encoder base 8.

  According to this embodiment, since the leaf spring 11 is separated from the encoder base 8 and the bending amount of the leaf spring 11 can be adjusted, the friction of the leaf spring 11 against the fixed tube without removing the encoder brush 10 from the lens barrel. The power can be adjusted easily. Further, since the encoder brush 10 and the leaf spring 11 are integrally formed, it is possible to reduce the number of parts and the number of assembling steps and the manufacturing cost.

  In this embodiment, the leaf spring 11 is brought into contact with the encoder base 8 attached to the fixed cylinder 6, but the leaf spring 11 may be brought into direct contact with the fixed cylinder 6.

  Further, the leaf spring 11 that gives the friction resistance to the gear cylinder 3 may be attached to the fixed cylinder 6 so as to be in contact with the gear cylinder 3 to form a stepped portion in the gear cylinder 3.

FIG. 1 is a conceptual diagram showing a cross section of a lens barrel according to an embodiment of the present invention. 2A to 2C are views for explaining the relationship between the fixed cylinder 6 and the gear cylinder 3. FIG. 3 is a conceptual diagram showing a cross section taken along line AA of FIG.

Explanation of symbols

  3: gear cylinder (moving cylinder), 4: moving lens group holding cylinder, 6: fixed cylinder, 8: encoder base (encoder member, second regulating means), 9: encoder (position detecting member), 10: encoder brush ( Brush), 11: leaf spring (friction load generating means), 15: screw (first regulating means), 30: tilt, 50: camera, 100: lens barrel.

Claims (5)

A movable cylinder that is supported by the stationary cylinder so as to be movable and is used to drive a movable lens group holding cylinder held by the fixed cylinder;
A friction load generating member that is attached to one of the fixed cylinder and the movable cylinder and contacts the other, thereby imparting a movement resistance to the movable cylinder;
First restriction means for restricting movement of the movable cylinder to a first range;
A second restricting means for restricting the movable cylinder to a second range outside the first range when the first restricting means is released;
Contact releasing means for releasing contact of the friction load generating member with either one of the fixed cylinder and the movable cylinder when the movable cylinder is in the second range. The lens barrel.   The friction load generating member is a leaf spring, and the contact release means is a step portion provided on a cylinder that contacts either the fixed cylinder or the movable cylinder with the friction load generating member. The lens barrel according to claim 1.   The lens mirror according to claim 1, further comprising a position detection member for detecting a position of the movable lens group holding cylinder, wherein the position detection member and the friction load generation member are integrally formed. Tube.   4. The lens barrel according to claim 3, wherein the position detection member is a brush and an encoder member made of a metal plate, and contact between the brush and the encoder member is not released even in the second range.   A camera comprising the lens barrel according to any one of claims 1 to 4.

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