JP2006276731A - Lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow a cam cylinder to be shared among a plurality of lens barrels different by product specifications without exerting an influence upon operability. <P>SOLUTION: With respect to the lens barrel, the cam cylinder where cam grooves inclined to a direction of an optical axis are formed and a rectilinear cylinder where a rectilinear groove in the direction of the optical axis is formed are disposed on concentric circles, and a cam pin provided on a lens holding frame is engaged with the cam groove and the rectilinear groove, and the lens holding frame is moved in the direction of the optical axis while following the cam groove. At least two first and second cam grooves different by inclinations are formed on the cam cylinder, and the cam pin is engaged with the first cam groove when the cam cylinder is used in a first lens barrel, and the cam pin is engaged with the second cam groove when the cam cylinder is used in a second lens barrel other than the first lens barrel. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lens barrel, and in particular, a cam cylinder in which a cam groove is formed and a rectilinear cylinder in which a rectilinear groove is formed are concentrically arranged, and a cam pin provided on a lens holding frame includes the cam groove and The present invention relates to a lens barrel that is engaged with a rectilinear groove and moves the lens holding frame following the cam groove when the cam cylinder or rectilinear cylinder is rotated.

  Conventionally, a lens barrel in which a lens such as a focus lens or a zoom lens is moved in the optical axis direction using a cam mechanism or a helicoid screw is known (for example, see Patent Document 1).

For example, a lens holding frame that holds a lens is disposed in a rectilinear cylinder in which a rectilinear groove in the optical axis direction is formed, and a cam groove that is inclined obliquely with respect to the optical axis direction is formed outside the rectilinear cylinder. A cam cylinder is arranged. Either one of the linear cylinder and the cam cylinder is rotatably arranged with respect to the other, and the lens holding frame is provided with a cam pin that penetrates the linear groove and engages the cam groove. When the cam cylinder or the rectilinear cylinder is rotated by a motor, an operation ring, or the like, the cam pin follows the cam groove and the lens holding frame is moved in the optical axis direction.
JP-A-8-69041

  By the way, in such a lens barrel, the lens movement amount (feeding amount) with respect to the rotation amount of the cam barrel or the rectilinear barrel is determined as a product specification for each model, and the lens feeding amount is determined by the cam groove of the cam barrel. It depends on the slope of the. Therefore, the cam barrel cannot be used in common with lens barrels with different product specifications. This is because, when the cam barrel is used in common, the lens extension amount differs from the product specification, resulting in problems in operability such as focus adjustment and zooming. As described above, the conventional lens barrel has a drawback in that a cam cylinder has to be produced for each model having different product specifications, resulting in high material costs and processing costs.

  The present invention has been made in view of such circumstances, and provides a lens barrel capable of commonly using a cam barrel with a plurality of lens barrels having different product specifications without affecting operability. For the purpose.

  In order to achieve the above object, the invention described in claim 1 includes a cam cylinder having a cam groove inclined obliquely with respect to the optical axis direction, and a rectilinear cylinder having a straight groove extending in the optical axis direction. Are arranged on concentric circles, and a cam pin provided on the lens holding frame is engaged with the cam groove and the rectilinear groove, and when the cam cylinder or the rectilinear cylinder is rotated, the lens holding frame is camped. A lens barrel that is moved in the optical axis direction following the groove, wherein the cam barrel is formed with at least two first cam grooves and second cam grooves having different inclinations, and the first lens. When the cam barrel is used in a lens barrel, the cam pin is engaged with the first cam groove, and the cam barrel is used in a second lens barrel different from the first lens barrel. In this case, the cam pin is engaged with the second cam groove.

  According to the present invention, a cam barrel can be used in common with a plurality of lens barrels in which the amount of movement (feeding amount) of the lens in the optical axis direction with respect to the amount of rotation of the cam barrel or rectilinear barrel differs in product specifications. The material cost and processing cost of the lens barrel are reduced, and the operability according to the product specifications can be secured.

  According to the present invention, a cam barrel can be used in common with a plurality of lens barrels in which the amount of movement (feeding amount) of the lens in the optical axis direction with respect to the amount of rotation of the cam barrel or rectilinear barrel differs in product specifications. The material cost and processing cost of the lens barrel are reduced, and the operability according to the product specifications can be secured.

  Hereinafter, preferred embodiments of a lens barrel according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a sectional view of a lens barrel to which an embodiment of the present invention is applied. As shown in the figure, in the lens barrel body 12 of the lens barrel 10, a focus lens 14 and a zoom lens 16 are arranged along the optical axis direction in order from the front end side (left side in FIG. 1) in the optical axis direction. A cylindrical fixed frame 28 is provided on the rear outer side of the lens barrel body 12.

  The focus lens 14 is held in a cylindrical lens holding frame 18, and three cam pins 20, 20, 20 extending in the radial direction project from the outer peripheral surface of the lens holding frame 18 (only one is shown). ). These cam pins 20 are inserted into rectilinear grooves 12 </ b> A extending in the optical axis direction that are formed through the front peripheral surface of the lens barrel body 12.

  A focus ring (cam barrel) 24 is disposed on the front outer side of the lens barrel body 12 so as to be rotatable with respect to the lens barrel body 12. Three cam grooves 24A, 24A, 24A (only one is shown) that are inclined with respect to the optical axis direction are formed on the inner peripheral surface of the focus ring 24, and the tip of the cam pin 20 is formed in the cam groove 24A. Inserted. As will be described in detail later, a cam groove (not shown in FIG. 1) having an inclination different from that of the cam groove 24A is further formed on the inner peripheral surface of the focus ring 24. A focus lever 26 is provided outside the rear end of the focus ring 24, and the focus lever 26 protrudes through the through hole of the fixed frame 28. The fixed frame 28 is fixed to the rear end side of the vertical portion 12B of the lens barrel body 12 with a screw 30. When the focus lever 26 is rotated, the focus ring 24 configured to be rotatable with respect to the lens barrel body 12 is rotated. At this time, since the cam pin 20 of the lens holding frame 18 is engaged with the rectilinear groove 12A of the lens barrel body 12, the lens holding frame 18 is in a state where the rotation of the lens holding frame 18 is restricted by the rectilinear groove 12A. Along with the rotation, the cam pin 20 follows the cam groove 24A, and the lens holding frame 18 moves in the optical axis direction.

  In addition, a circumferential long groove 24B is formed in a substantially central portion of the focus ring 24, and a regulating screw 32 is attached and fixed to the lens barrel body 12 through the long groove 24B. . Thereby, the rotation range of the focus ring 24 is restricted to a range corresponding to the length of the long groove 24B. Further, convex portions 24C are integrally formed at several locations on the inner peripheral surface of the rear end of the focus ring 24, and these convex portions 24C are circumferential grooves formed on the outer peripheral surface at the substantially center of the lens barrel body 12. 12C is engaged. Accordingly, the focus ring 24 is supported at a predetermined position in the axial direction so as to be rotatable with respect to the lens barrel body 12. A corrugated spring 34 is disposed between the front end of the focus ring 24 and the flange 12D of the lens barrel body 12 in order to prevent the focus ring 24 from rattling in the optical axis direction with respect to the lens barrel body 12. As a result, the focus ring 24 is urged rearward, and the convex portion 24C of the focus ring 24 is shifted to the rear surface of the groove 12C of the lens barrel body 12, thereby preventing the focus ring 24 from rattling. Further, the focus ring 24 can adjust the rotational torque by the strength of the elastic force of the corrugated spring 34.

  The zoom lens 16 is held in a lens holding frame 36, and three cam pins 38, 38, 38 extending in the radial direction protrude from the outer peripheral surface of the lens holding frame 36 (only one is shown). These cam pins 38 are inserted into rectilinear grooves 12 </ b> E extending in the optical axis direction formed through the inner peripheral surface on the rear side of the lens barrel body 12.

  A zoom ring (cam barrel) 40 is disposed on the rear outer side of the lens barrel body 12 so as to be rotatable with respect to the lens barrel body 12. Three cam grooves 40A, 40A, and 40A inclined obliquely with respect to the optical axis direction are formed on the inner peripheral surface of the zoom ring 40, and the tip of the cam pin 38 is fitted into the cam groove 40A. As will be described in detail later, a cam groove (not shown in FIG. 1) having an inclination different from that of the cam groove 40A is further formed on the inner peripheral surface of the zoom ring 40.

  On the front outer side of the zoom ring 40, a convex portion 40B having a hook-like cross section is integrally formed. A zoom lever 42 is provided at the tip of the convex portion 40 </ b> B, and the zoom lever 42 protrudes outside through the through hole of the fixed frame 28. When the zoom lever 42 is rotated, the zoom ring 40 configured to be rotatable with respect to the lens barrel body 12 rotates. At this time, since the cam pin 38 of the lens holding frame 36 is engaged with the rectilinear groove 12E of the lens barrel body 12, the lens holding frame 36 is in a state where the rotation of the lens retaining frame 36 is restricted by the rectilinear groove 12E. Along with the rotation, the cam pin 38 follows the cam groove 40A, and the lens holding frame 36 moves in the optical axis direction.

  Further, convex portions 40C are integrally formed at several locations on the inner peripheral surface of the rear end of the zoom ring 40, and the convex portions 40C are formed in circumferential grooves 12F formed on the outer peripheral surface of the rear end of the lens barrel body 12. Engaged. Further, a corrugated spring 44 is disposed between the flange 40D on the front end side of the zoom ring 40 and the vertical portion 12B of the lens barrel body 12. As a result, the zoom ring 40 is urged rearward, and the convex portion 40C of the zoom ring 40 is biased to the rear surface of the groove 12F of the lens barrel body 12, and the play of the zoom ring 40 is prevented. Further, the zoom ring 40 can adjust the rotation torque by the strength of the elastic force of the corrugated spring 44.

  A mount ring 46 is fixed to the rear end of the fixed frame 28 with a screw 48 in order to fix the lens barrel 10 to a camera body (not shown). An iris (aperture) 50 is disposed between the focus lens 14 and the zoom lens 16, and the iris 50 is driven by an iris motor 52. The iris 50 is fixed to the front end side of the vertical portion 12 </ b> B of the lens barrel body 12 with a screw 56.

  Next, the configuration of the cam cylinder (focus ring 24, zoom ring 40) will be described. In addition, since these structures are common, below, the cam cylinder 60 is demonstrated on behalf of these.

  FIG. 2 is an external perspective view showing an embodiment of the cam barrel 60, and FIG. 3 is a development view of the cam barrel 60 shown in FIG. FIG. 4 is an external perspective view showing another embodiment of the cam cylinder 60. In these drawings, the cam cylinder 60 is simply displayed for convenience of explanation.

  As shown in FIGS. 2 and 3, on the inner peripheral surface of the cam cylinder 60, there are three first cam grooves 62, 62, 62 and three second inclined at an angle with respect to the optical axis direction. Cam grooves 64, 64, 64 are alternately formed at equal intervals in the circumferential direction. One of the cam grooves 62 and 64 is open, and the tip of the cam pin 20 (or 38) of the lens holding frame 18 (or 36) shown in FIG.

  The first cam groove 62 and the second cam groove 64 are inclined at different angles, and the two inclinations of the lens barrel 10 are different depending on the product specifications in terms of the product extension of the lens with respect to the rotation amount of the cam barrel 60. It corresponds to. That is, when this cam barrel 60 is used in one lens barrel 10, the tip of the cam pin 20 (or 38) of the lens holding frame 18 (or 36) is inserted into the first cam groove 62, and the other lens is inserted. When the lens barrel 10 is used, the tip of the cam pin 20 (or 38) of the lens holding frame 18 (or 36) is fitted into the second cam groove 64. The lens extension amount with respect to the rotation amount of the cam barrel 60 in each lens barrel 10 is an amount corresponding to the inclination of the cam groove into which the tip of the cam pin 20 (or 38) of the lens holding frame 18 (or 36) is inserted. It becomes. Accordingly, the cam barrel 60 (the focus ring 24 and the zoom ring 40) can be used in common with two types of lens barrels 10 having different product specifications.

  Further, the cam grooves 62 and 64 formed in the cam cylinder 60 are not limited to those having a bottom as shown in FIGS. 2 and 3, and are formed through the peripheral surface of the cam cylinder 60 as shown in FIG. 4. The through holes may be the first cam groove 62 and the second cam groove 64.

  The operation of the lens barrel configured as described above will be described.

  When the focus lever 26 is rotated, the focus ring 24 disposed so as to be rotatable with respect to the lens barrel body 12 is rotated. At this time, since the cam pin 20 of the lens holding frame 18 is engaged with the cam groove 24A of the focus ring 24 via the rectilinear groove 12A of the lens barrel body 12, the lens holding frame 18 is rotated by the rectilinear groove 12A. In a state where the movement is restricted, the focus ring 24 is rotated and moved in the optical axis direction. In this way, the focus lens 14 held by the lens holding frame 18 is extended in the optical axis direction, and focus adjustment is performed.

  Further, when the zoom lever 42 is rotated, the zoom ring 40 disposed so as to be rotatable with respect to the lens barrel body 12 is rotated. At this time, since the cam pin 38 of the lens holding frame 36 is engaged with the cam groove 40A of the zoom ring 40 via the rectilinear groove 12E of the lens barrel body 12, the lens holding frame 36 is rotated by the rectilinear groove 12E. In a state where the movement is restricted, the zoom ring 40 is moved in the optical axis direction following the rotation of the zoom ring 40. In this way, the zoom lens 16 held by the lens holding frame 36 is extended in the optical axis direction, and zooming is performed.

  When the focus ring 24 (or zoom ring 40) is used in another lens barrel 10, the cam groove 24A into which the tip of the cam pin 20 (or 38) of the lens holding frame 18 (or 36) is fitted. The tip of the cam pin 20 (or 38) of the lens holding frame 18 (or 36) of the other lens barrel 10 is inserted into a cam groove having an inclination different from (or 40A). When the focus lever 26 (or the zoom lever 42) is operated in this state, the focus ring 24 (or the zoom ring 40) is rotated, and the focus lens is moved out in accordance with the product specifications of the other lens barrels 10. 14 (or zoom lens 16) is moved in the optical axis direction, and focus adjustment (or zooming) is performed.

  In this way, the focus ring 24 and the zoom are operated by the two types of lens barrels 10 in which the movement amounts (feeding amounts) of the focus lens 14 and the zoom lens 16 in the optical axis direction with respect to the rotation amounts of the focus ring 24 and the zoom ring 40 are different in product specifications. The ring 40 can be used in common, the material cost and processing cost of the lens barrel 10 can be reduced, and the operability according to the product specifications can be ensured.

  In the above embodiment, the configuration in which two types of cam grooves 62 and 64 are provided in the cam cylinder 60 (the focus ring 24 and the zoom ring 40) is exemplified, but the present invention is not limited to this, and three or more types of cam grooves are provided. The cam barrel 60 may be commonly used by three or more types of lens barrels 10 having different product specifications.

  In the above embodiment, the lens barrel body 12 is provided with the rectilinear grooves 12A and 12E, and the focus ring 24 and the zoom ring 40 are provided with the cam grooves 24A and 40A. However, the present invention is not limited to this. The lens barrel body 12 may be provided with a cam groove, and the focus ring 24 and the zoom ring 40 may be provided with straight grooves.

  In the above-described embodiment, the configuration in which the focus ring 24 and the zoom ring 40 are disposed outside the lens barrel body 12 is exemplified. However, the present invention is not limited to this. For example, the focus ring 24 and the zoom ring 40 are disposed outside. A configuration in which the lens barrel body 12 is disposed may be used.

  In the above-described embodiment, the configuration in which cam grooves having different inclinations are formed in both the focus ring 24 and the zoom ring 40 is illustrated. However, the present invention is not limited to this, and either the focus ring 24 or the zoom ring 40 is used. It may be.

It is the block diagram which showed embodiment of the lens barrel which concerns on this invention. It is an external appearance perspective view showing one embodiment of a cam cylinder. FIG. 3 is a development view of the cam cylinder shown in FIG. 2. It is an external appearance perspective view showing other embodiment of a cam cylinder.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Lens barrel, 12 ... Lens barrel body, 12A, 12E ... Straight groove, 14 ... Focus lens, 16 ... Zoom lens, 18 ... Lens holding frame, 20 ... Cam pin, 24 ... Focus ring, 24A ... Cam groove, 26 ... focus lever, 28 ... fixed frame, 36 ... lens holding frame, 38 ... cam pin, 40 ... zoom ring, 40A ... cam groove, 42 ... zoom lever, 60 ... cam barrel, 62 ... first cam groove, 64 ... first 2 cam grooves

Claims (1)

A cam pin having a cam groove formed obliquely with respect to the optical axis direction and a straight cylinder having a straight groove formed in the optical axis direction are arranged concentrically and are provided on the lens holding frame. Is a lens barrel that is engaged with the cam groove and the rectilinear groove, and when the cam cylinder or the rectilinear cylinder is rotated, the lens holding frame is moved in the optical axis direction following the cam groove. And
The cam cylinder is formed with at least two first cam grooves and second cam grooves having different inclinations,
When the cam barrel is used in the first lens barrel, the cam pin is engaged with the first cam groove, and the cam is used in a second lens barrel different from the first lens barrel. A lens barrel characterized in that, when a tube is used, the cam pin is engaged with the second cam groove.

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