Lens barrel

Patent metadata

Field	Value
Publication number	US-9778544-B2
Application number	US-201514596705-A
Country	US
Kind code	B2
Filing date	Jan 14, 2015
Priority date	Jan 22, 2014
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

A lens barrel includes a first drive mechanism which rotates a cam ring to move a cam-driven lens frame, holding a lens group, in accordance with a cam groove; a second drive mechanism which screw-engages a nut with a feed screw, biases a nut-driven lens frame to abut the nut, and moves the nut-driven lens frame. The cam-driven lens frame is positioned adjacent to the nut-driven lens frame on a reverse side to the biasing direction, and driving ranges of these lens frames partially overlap each other. The first drive mechanism includes a cam-driven member, separate from the cam-driven lens frame, which is linearly guided and provided with a cam follower which engages with the cam groove of the cam ring; and a biasing member which biases the cam-driven lens frame to abut against the cam-drive member, so that the cam-driven lens frame moves with the cam-driven member.

First claim

What is claimed is:

1. A lens barrel comprising:
a first drive mechanism including a stationary barrel, a cam ring configured to be supported in said stationary barrel, and a cam-driven lens frame configured to hold a lens group that constitutes part of a photographing optical system, wherein:
said first drive mechanism is configured to rotate said cam ring to change a position, with respect to an optical axis direction, of said cam-driven lens frame, in accordance with a contour of a cam groove formed on an inner peripheral surface of said cam ring, and,
an inner ring, which is restricted from rotating relative to said stationary barrel, is supported inside said cam ring; and

a second drive mechanism including a nut, a feed screw extending in the optical axis direction and screw-engaged with said nut to allow said nut to relatively move therealong, and a nut-driven lens frame configured to hold another lens group that is different to said lens group, wherein said second drive mechanism is configured to bias said nut-driven lens frame in a biasing-direction to abut against said nut in the optical axis direction, and said second drive mechanism is configured to change a position of said nut-driven lens frame with respect to the optical axis direction by rotating said feed screw to in turn move said nut in the optical axis direction,
wherein said nut-driven lens frame and said cam-driven lens frame are arranged so that said cam-driven lens frame is positioned adjacent to said nut-driven lens frame, and wherein driving ranges of said nut-driven lens frame and said cam-driven lens frame partially overlap each other in the optical axis direction, and
wherein said first drive mechanism further includes:
a cam-driven member, which is formed as a separate member from said cam-driven lens frame, linearly guided in the optical axis direction and is provided with a cam follower which engages with said cam groove of said cam ring, wherein said cam-driven member is slidably fitted in a bottomed linear guide groove formed on an outer peripheral surface of said inner ring so that said cam follower of said cam-driven member projects radially outward relative to the outer peripheral surface of said inner ring; and
a biasing member which biases, in the optical axis direction, said cam-driven lens frame in a direction toward and to closely approach said nut-driven lens frame to thereby cause said cam-driven lens frame to abut against said cam-drive member, so that said cam-driven lens frame is moved in the optical axis direction with said cam-driven member.

2. The lens barrel according to claim 1 , wherein said cam-driven member comprises:
a long and thin plate-shaped guide key part which is elongated in the optical axis direction and slidably fitted into said linear guide groove of said inner ring; and
an upright part formed at an end, with respect to the optical axis direction, of said guide key part and extending in a direction that is orthogonal to the optical axis,
wherein said cam-driven lens frame abuts against said upright part by a biasing force of said biasing member.

3. The lens barrel according to claim 2 , further comprising an auxiliary guide rod which is located on an outer side of said cam ring and is fixed to said stationary barrel, the central longitudinal axis of said auxiliary guide rod extending in the optical axis direction, and
wherein said upright part of said cam-driven member is provided with a guided part, which is slidably supported in the optical axis direction by said auxiliary guide rod.

4. The lens barrel according to claim 2 , wherein said cam-driven lens frame comprises:
at least one arm which extends in an outer radial direction, centered from the optical axis, from a lens holding portion, which holds said lens group; and
a guided portion formed on an outer end of said arm, said guided portion being slidably supported in the optical axis direction on a lens-frame guide rod, the central longitudinal axis thereof extending in the optical axis direction, which is fixed to said stationary barrel,
wherein said arm abuts against said upright part of said cam-driven member by a biasing force of said biasing member.

5. The lens barrel according to claim 4 , wherein said biasing member comprises a tension spring, one and the other end of which is engaged onto said stationary barrel and said cam-driven lens frame, respectively, wherein said tension spring extends and contracts in the optical axis direction.

6. The lens barrel according to claim 1 , wherein said lens group that is held by said cam-driven lens frame is provided on the image side, with respect to the optical axis direction, of a lens group which is held by said nut-driven lens frame.

7. The lens barrel according to claim 6 , wherein the lens group that is held by said cam-driven lens frame is provided closest to the image side of said photographing optical system, and
wherein the lens group that is held by said nut-driven lens frame is provided adjacent to, and on the object side of, the lens group that is provided closest to the image side.

8. The lens barrel according to claim 1 , wherein said second drive mechanism rotates said feed screw by a stepping motor which is mounted onto said stationary barrel.

9. The lens barrel according to claim 1 , wherein said photographing optical system comprises a zoom optical system, said cam-driven lens frame and said nut-driven lens frame being respectively moved in the optical axis direction during a zooming operation, and wherein said nut-driven lens frame is solely moved in the optical axis direction during a focusing operation on an object.

10. The lens barrel according to claim 1 , further comprising a second cam-driven lens frame which holds another lens group that constitutes part of said photographing optical system, and is controlled to move in the optical axis direction by another cam groove that is different from the cam groove that is used to drive said cam-driven lens frame,
wherein, in a ready-to-photograph state, said cam-driven lens frame and said second cam-driven lens frame are respectively positioned at either side of said nut-driven lens frame with respect to the optical axis direction.

11. The lens barrel according to claim 10 , further comprising a second cam ring which is a separate member from said cam ring and rotates with said cam ring, wherein said another cam groove which drives said second cam-driven lens frame is formed in said second cam ring.

Assignees

• Hoya Corp

Inventors

• Sasaki Takamitsu

Classifications

• G03B2205/00

  Adjustment of optical system relative to image or object surface other than for focusing · CPC title

• G02B7/102 Primary

  controlled by a microcomputer (cameras with interchangeable lenses G03B17/14) · CPC title

• G03B3/10 Primary

  Power-operated focusing · CPC title

• G03B5/00

  Adjustment of optical system relative to image or object surface other than for focusing · CPC title

• G03B2205/0092

  Physics · mapped topic