JP2010181611A - Lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the increase of a dimension in a radial direction and moreover, to facilitate a photographing operation. <P>SOLUTION: A lens barrel includes: lens moving mechanisms 30, 40 and 50 which change the positions along an optical axis of movable lens groups ML1, ML2 and ML3 with respect to a lens barrel body 10, when a rotational force is input; a focus ring 20 which is rotatably disposed in the circumferential part of the lens barrel body 10; an output unit 80 which selectively outputs the rotation of the focus ring 20 and the drive of an incorporated motor for focusing 81 to the lens moving mechanisms 30, 40 and 50; and a diaphragm mechanism 60 which changes the quantity of light passing through the optical axis in the lens barrel body 10. The output unit 80 is disposed in a part on a top end side from the diaphragm mechanism 60 in the lens barrel body 10 and the focus ring 20 is disposed in a part being the circumference of the output unit 80. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a lens barrel, and more particularly to a lens barrel in which the position along the optical axis of a movable lens with respect to a barrel main body is changed by driving a focusing actuator and manually operating a focus ring. Is.

  Some lens barrels used in cameras include a focus ring and a focusing actuator. The focus ring is an annular member that is operated when the focus is manually adjusted, and is rotatably disposed on the outer peripheral portion of the barrel main body. The focusing actuator is a drive source for performing focus adjustment, and is disposed inside the barrel main body.

  In this type of lens barrel, when the focus ring is rotated, the lens moving mechanism configured in the barrel main body operates according to the operation amount, and the position along the optical axis of the lens group with respect to the barrel main body is set. The focus can be adjusted by changing. On the other hand, when the focusing actuator is driven according to the drive signal from the camera body, the lens mechanism can be operated and the focus can be automatically adjusted without operating the focus ring (see, for example, Patent Document 1). .

Japanese Patent Laid-Open No. 2004-233402

  By the way, recent lens barrels are also provided with a diaphragm mechanism disposed inside the lens barrel body and operating the diaphragm mechanism in response to a drive signal from the camera body. According to such a lens barrel, in addition to focusing by the automatic focus adjustment described above, the exposure can also be accurately controlled by the automatic adjustment of the aperture mechanism, thereby facilitating the operation during photography. It becomes possible.

  However, in order to realize automatic focus adjustment and automatic aperture adjustment, an actuator for operating the aperture mechanism or an actuator disposed in the camera body is transmitted to the aperture mechanism on the outer periphery of the focusing actuator. The power transmission mechanism is required, and the size in the radial direction is increased.

  In view of the above circumstances, an object of the present invention is to provide a lens barrel capable of facilitating photographing operation while suppressing an increase in radial dimension.

  In order to achieve the above object, a lens barrel according to the present invention includes a movable lens that is movably disposed along an optical axis inside a barrel main body, and the barrel main body when a rotational force is input. A lens moving mechanism that changes the position of the movable lens along the optical axis, a focus ring that is rotatably arranged on the outer periphery of the lens barrel body, and rotation of the focus ring and driving of a built-in focusing actuator Each of which is transmitted as a rotational force to the lens moving mechanism, and an aperture mechanism that changes the amount of light passing through the optical axis inside the lens barrel body, and the aperture mechanism inside the lens barrel body In addition, the output unit is disposed at a portion closer to the distal end portion, and a focus ring is disposed at a portion that is an outer periphery of the output unit.

  According to the present invention, since the output unit including the focusing actuator is disposed on the distal end side of the lens barrel body with respect to the diaphragm mechanism, the actuator is disposed on the actuator or the camera body for operating the diaphragm mechanism. The power transmission mechanism for transmitting the drive of the actuator to the aperture mechanism does not cause a situation where it overlaps with the output unit in the radial direction, and photography can be easily performed without increasing the size in the radial direction. .

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

  FIG. 1 shows a lens barrel that is an embodiment of the present invention. The lens barrel exemplified here is detachably attached to a camera body (not shown) via a mount 11 provided at a base end portion of a barrel body 10 having a cylindrical shape. In addition, a focus ring 20 is provided on the outer periphery of the distal end on the objective side, and a first fixed lens group FL1, a second fixed lens group FL2, and a third fixed lens group FL3 are provided inside the barrel body 10.

  The focus ring 20 is an annular member having an operation output gear 21 on its inner peripheral surface. The focus ring 20 is disposed so as to be rotatable about the axis of the lens barrel body 10 with the operation output gear 21 exposed on the inner peripheral surface of the lens barrel body 10.

  The first fixed lens group FL1 and the second fixed lens group FL2 are disposed at the distal end portion on the objective side in the lens barrel body 10, and the respective optical axes are aligned with the axis of the lens barrel body 10. And attached to the lens barrel body 10 via individual lens support frames FLM1 and FLM2. The third fixed lens group FL3 is disposed at the base end portion on the mount 11 side in the lens barrel body 10, and the lens support frame FLM3 and the optical axis are aligned with the axis of the lens barrel body 10. It is attached to the lens barrel body 10 via a flange member F.

  In addition, a vertical groove cylinder (lens moving mechanism) 30 is disposed inside the lens barrel body 10 at a portion located between the second fixed lens group FL2 and the third fixed lens group FL3. As shown in the exploded perspective view of the main part of FIG. 2, the longitudinal groove cylinder 30 includes a cylindrical base end groove cylinder part 31 and a distal end groove cylinder part having a cylindrical diameter smaller than that of the base end groove cylinder part 31. 32, and a cylindrical member formed integrally in a state where the axial center of the proximal groove cylinder portion 31 and the axial center of the distal groove cylinder portion 32 are aligned with each other. As shown in FIG. 1, the vertical groove cylinder 30 has lens support frames FLM1, FLM2 and a flange member F that support the second fixed lens group FL2 in a state in which the axis is aligned with the axis of the lens barrel body 10. It is attached to the barrel main body 10 via

  As shown in FIG. 2, two longitudinal grooves 31 a and 31 b are formed in the base end groove cylinder portion 31 of the longitudinal groove cylinder 30, and one longitudinal groove cylinder portion 32 of the longitudinal groove cylinder 30 is provided with one longitudinal groove. A groove 32a and one circumferential groove 32b are formed. The two vertical grooves 31 a and 31 b of the proximal end groove cylinder part 31 and the vertical groove 32 a of the distal end groove cylinder part 32 are slit-like openings extending along the axis of the vertical groove cylinder 30, respectively. The circumferential groove 32 b is a slit-like opening extending along the circumferential direction of the distal end groove cylinder portion 32, and is provided in a portion of the distal end groove cylinder portion 32 that is close to the proximal end groove cylinder portion 31.

  As shown in FIG. 1, a focus gearing (lens moving mechanism) 40 is disposed on the outer periphery of the vertical groove cylinder 30 inside the barrel main body 10, while the vertical groove cylinder 30 has an inside. A focus cam cylinder (lens moving mechanism) 50 is provided.

  The focus gear ring 40 is a cylindrical member rotatably disposed on the outer peripheral portion of the proximal end groove cylinder portion 31 in the longitudinal groove cylinder 30. The focus gear ring 40 is provided with a driven gear 41 and a connecting bracket portion 42. The driven gear 41 is an inner peripheral gear formed on the inner peripheral surface of the tip portion of the focus gear ring 40. The connection bracket portion 42 is a portion that extends from the inner peripheral surface of the distal end portion of the focus gear ring 40 toward the central direction and then bends toward the distal end side in the axial direction. The connecting bracket portion 42 has a screw insertion hole 42a at the center of the bent portion.

  The focus cam cylinder 50 includes a proximal cam cylinder part 51 having a cylindrical shape and a distal cam cylinder part 52 having a cylindrical shape smaller in diameter than the proximal cam cylinder part 51, and the proximal cam cylinder part 51. This is a cylindrical member that is integrally molded in a state where the shaft center and the shaft center of the tip cam tube portion 52 are aligned with each other. As shown in FIG. 1, the focus cam cylinder 50 has a proximal cam cylinder portion 51 fitted to the inner circumferential surface of the proximal groove cylinder section 31 with respect to the longitudinal groove cylinder 30 and a distal cam cylinder portion 52. By being fitted to the inner peripheral surface of the tip groove cylinder portion 32, the tip groove cylinder portion 32 is disposed so as to be relatively rotatable about the axis of each other.

  As shown in FIG. 2, the proximal cam barrel 51 of the focus cam barrel 50 is formed with two spiral grooves 51a and 51b, and the distal cam barrel 52 of the focus cam barrel 50 has one spiral. A groove 52a and a screw fastening hole 52b are formed. The two spiral grooves 51 a and 51 b of the proximal cam barrel 51 and the spiral groove 52 a of the distal cam barrel 52 extend spirally around the axis of the focus cam barrel 50. However, the spiral groove 52a of the distal cam cylinder 52 is formed so that the spiral direction is opposite to the two spiral grooves 51a and 51b of the proximal cam cylinder 51. The screw fastening hole 52b is a screw hole formed from the outer peripheral surface of the tip cam cylinder portion 52 toward the axis. As shown in FIG. 1, a connecting screw 55 is fastened to the screw fastening hole 52b. The connection screw 55 is fastened to the screw fastening hole 52b via a screw insertion hole 42a formed in the connection bracket portion 42 of the focus gear ring 40 and a circumferential groove 32b formed in the vertical groove cylinder 30, and the circumferential groove 32b is The focus gear ring 40 and the focus cam cylinder 50 are connected to each other.

  In the focus cam cylinder 50, a first movable lens group (movable lens) ML1 is arranged inside the distal cam cylinder section 52, and a second movable lens group (movable lens) is arranged inside the proximal cam cylinder section 51. ML2 and a third movable lens group (movable lens) ML3 are disposed. The first movable lens group ML1, the second movable lens group ML2, and the third movable lens group ML3 have individual lens support frames MLM1, MLM2, and an individual lens support frame MLM1, MLM2, with their respective optical axes aligned with the axis of the lens barrel body 10. It is supported by MLM3.

  As shown in FIG. 2, the individual lens support frames MLM1, MLM2, and MLM3 are formed with boss portions B1, B2, and B3 on the outer peripheral surface. Further, as shown in FIG. Cam pins P1, P2, and P3 are attached to the tip ends of B2 and B3. The cam pin P1 provided on the lens support frame MLM1 of the first movable lens group ML1 is provided on the distal groove cylinder portion 32 of the longitudinal groove cylinder 30 via the spiral groove 52a provided on the distal cam cylinder portion 52 of the focus cam cylinder 50. The vertical groove 32a is slidably fitted. The cam pin P2 provided on the lens support frame MLM2 of the second movable lens group ML2 and the cam pin P3 provided on the lens support frame MLM3 of the third movable lens group ML3 are provided on the proximal cam cylinder portion 51 of the focus cam cylinder 50, respectively. It is slidably fitted to individual vertical grooves 31a and 31b provided in the base end groove cylinder portion 31 of the vertical groove cylinder 30 via the individual spiral grooves 51a and 51b.

  In addition, a diaphragm mechanism 60 and a diaphragm motor 70 are disposed in a portion of the proximal cam cylinder portion 51 of the focus cam cylinder 50 that is close to the distal cam cylinder portion 52. The diaphragm mechanism 60 is a variable mechanism for enlarging / reducing the inner diameter of the opening formed in the center, although not shown in the drawing. The aperture motor 70 is a drive source for operating the aperture mechanism 60 when a drive signal is given from a camera body (not shown). The diaphragm motor 70 includes a lens support frame MLM2 and a third movable frame that support the proximal groove tube portion 31 of the longitudinal groove tube 30 and the second movable lens group ML2 at a portion located on the proximal end side of the diaphragm mechanism 60. It is accommodated in a space provided between the lens support frame MLM3 and the lens group ML3.

  On the other hand, an output unit 80 is disposed in the space between the inner peripheral surface of the focus ring 20 and the outer peripheral surface of the tip groove tube portion 32 in the longitudinal groove tube 30 inside the lens barrel body 10. The output unit 80 includes a focusing motor (focusing actuator) 81, an input gear 82, and a drive gear 83, and power transmission means (not shown) is configured therein, and the focusing motor 81 When driven and when the input gear 82 is rotated, the drive gear 83 is rotated. This output unit 80 supports the second fixed lens group FL2 with the input gear 82 meshed with the operation output gear 21 of the focus ring 20 and the drive gear 83 meshed with the driven gear 41 of the focus gear ring 40. It is attached to the barrel main body 10 via the lens support frame MLM2.

  In the lens barrel configured as described above, when mounted on the camera body (not shown) via the mount 11, the control device of the camera body (not shown), the aperture motor 70, and the output unit 80 are focused. Each of the aperture motors 70 and the focusing motor 81 is driven in response to a drive signal output from the control device.

  When the diaphragm motor 70 is driven, the diaphragm mechanism 60 operates as described above to enlarge / reduce the opening, so that the amount of light passing through the optical axis in the lens barrel body 10 changes. It becomes possible to control the exposure during photography.

  On the other hand, when the focusing motor 81 is driven, the drive gear 83 is rotated via power transmission means (not shown). The rotation of the drive gear 83 is transmitted to the focus gear ring 40 via the driven gear 41 and further transmitted to the focus cam barrel 50 via the connecting screw 55. The focus gear ring 40 and the focus cam barrel 50 are connected to the lens barrel body. Rotate around 10 axes. When the focus cam cylinder 50 rotates, for example, the state shown in FIG. 3 is changed to the state shown in FIG. That is, since the cam pins P1, P2, P3 fitted in the spiral grooves 51a, 51b, 52a of the focus cam cylinder 50 are fitted in the vertical grooves 31a, 31b, 32a formed in the vertical groove cylinder 30, When the focus cam cylinder 50 cannot rotate around the axis of the cylinder main body 10, it moves along the longitudinal grooves 31 a, 31 b, 32 a by the action of the spiral grooves 51 a, 51 b, 52 a. When the cam pins P1, P2, and P3 move along the longitudinal grooves 31a, 31b, and 32a, the first movable lens group ML1, the second movable lens group ML2, and the third movable lens group MLM1, MLM2, and MLM3 that are supported by the lens support frames MLM1, MLM2, and MLM3. The position of the movable lens group ML3 changes along the optical axis, and the focus can be adjusted.

  As a result, according to the lens barrel, it is possible to accurately perform focusing by automatic focus adjustment, and it is possible to accurately control exposure by automatic adjustment of the aperture mechanism 60. It becomes possible to facilitate.

  In addition, since the diaphragm motor 70 is disposed at a position closer to the camera body (not shown) than the diaphragm mechanism 60, the output unit 80 is disposed at a position closer to the objective side than the diaphragm mechanism 60. Also, there is no possibility of incurring a situation in which the radial dimension increases.

  Further, since the focus ring 20 is directly meshed with the output unit 80 disposed on the objective side relative to the aperture mechanism 60, the focus ring 20 is disposed at a position closer to the distal end side in the lens barrel. Will be established. Therefore, the operability of the focus ring 20 can be improved, and the input gear 82 of the output unit 80 can be rotated without transmission loss when the focus ring 20 is rotated. Even when the focus ring 20 is rotated, it goes without saying that the drive gear 83 of the output unit 80 rotates and the focus can be adjusted by the same operation as described above.

  In the above-described embodiment, the lens barrel is provided with the diaphragm motor 70 and the diaphragm mechanism 60 is operated by the diaphragm motor 70. However, the diaphragm motor provided on the camera body side is exemplified. The present invention can also be applied to a mechanism in which the diaphragm mechanism 60 is operated. In this case, a power transmission mechanism is disposed between the diaphragm motor provided in the camera body and the diaphragm mechanism 60. The output unit is disposed on the distal end side of the diaphragm mechanism 60. It does not overlap with 80 in the radial direction, and there is no risk of increasing the radial dimension.

1 is a cross-sectional side view showing a lens barrel that is an embodiment of the present invention. It is a principal part disassembled perspective view of the lens-barrel shown in FIG. It is a schematic diagram which shows notionally the 1st operation state of the lens-barrel shown in FIG. It is a schematic diagram which shows notionally the 2nd operation state of the lens-barrel shown in FIG.

DESCRIPTION OF SYMBOLS 10 Lens barrel body 20 Focus ring 30 Vertical groove cylinder 40 Focus gear ring 50 Focus cam cylinder 55 Connecting screw 60 Aperture mechanism 70 Aperture motor 80 Output unit 81 Focusing motor 82 Input gear 83 Drive gear ML1 First movable lens group ML2 First 2 movable lens group ML3 3rd movable lens group

Claims (1)

A movable lens disposed inside the lens barrel body so as to be movable along the optical axis;
A lens moving mechanism that changes a position along the optical axis of the movable lens with respect to the lens barrel body when a rotational force is input;
A focus ring rotatably disposed on the outer periphery of the lens barrel body;
An output unit that transmits the rotation of the focus ring and the drive of the built-in focusing actuator to the lens moving mechanism as rotational force, respectively;
A diaphragm mechanism that changes the amount of light that passes through the optical axis inside the barrel main body, and the output unit is disposed at a position closer to the tip than the diaphragm mechanism inside the barrel main body. In addition, the lens barrel is characterized in that a focus ring is disposed at a portion that is an outer periphery of the output unit.

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