Lens device and correction method for lens device

Patent metadata

Field	Value
Publication number	US-10088654-B2
Application number	US-201615228403-A
Country	US
Kind code	B2
Filing date	Aug 4, 2016
Priority date	Mar 28, 2014
Publication date	Oct 2, 2018
Grant date	Oct 2, 2018

Abstract

This invention provides a lens device and a correction method therefor whereby the focal position of the lens device can be corrected with high accuracy even if a lens surface shape or the like is not uniform. A ring-shaped lens fixing frame 52 is mounted on the outer periphery of a lens 51. A gear 53 is formed on the lens fixing frame 52 in the circumferential direction. A gear 54, which engages with the gear 53, is rotated by a motor 20A. Then, the lens 51 rotates about the optical axis L thereof. Further, a rack 57, which extends in the direction of the optical axis L, is formed on a part of the lens fixing frame 52. A pinion 58 engages with the teeth 57A of the rack 57, and the pinion 58 is rotated by another motor 20B. Then, the rack 57 moves in the direction of the optical axis L, and thus the lens 51 moves in the direction of the optical axis L. Since the lens 51 rotates about the optical axis L thereof, even if the surface shape or the like of the lens 51 is uneven in the circumferential direction, improvement can be realized.

First claim

What is claimed is:

1. A lens device comprising:
a plurality of lenses that an optical axis is common;
a lens moving mechanism that moves one or more lenses, which are included in the plurality of lenses, in a direction of an optical axis of the plurality of lenses;
a storage section that stores a plurality of positions of the plurality of lenses in the direction of the optical axis and a plurality of rotation angles respectively corresponding to the plurality of positions; and
a lens rotating mechanism that rotates at least one lens, which are included in the plurality of lenses, about the optical axis of the lens by a rotation angle corresponding to a position of the lens, which is moved by the lens moving mechanism, in the direction of the optical axis, among the plurality of rotation angles stored in the storage section, and that is driven separately from the lens moving mechanism.

2. The lens device according to claim 1 , wherein the at least one lens, which is rotated by the lens rotating mechanism, is a lens, of which at least one of a surface shape or a refractive index is relatively uneven in a circumferential direction orthogonal to the optical axis and centered on the optical axis, among the plurality of lenses.

3. The lens device according to claim 1 , wherein the at least one lens, which is rotated by the lens rotating mechanism, is a lens, of which an optical sensitivity is relatively low, among the plurality of lenses.

4. The lens device according to claim 1 ,
wherein the lens device includes a zoom optical system, and
wherein the lens, which is moved by the lens moving mechanism, is a lens included in the zoom optical system.

5. The lens device according to claim 1 ,
wherein the plurality of lenses includes a focus optical system that is moved by a first movement unit so as to thereby adjust a focal position, a master optical system that is moved by a second movement unit, which is smaller than a movement unit of the focus optical system, so as to thereby adjust the focal position, and a zoom optical system that changes a zoom ratio, and
wherein the lens device further comprises: a diaphragm that restricts an amount of incident light; and adjustment control device for performing at least one of adjustment of the focal position performed by the focus optical system or adjustment of the focal position performed by the master optical system, on the basis of an amount of variation in focal position which is predetermined to correspond to the zoom ratio of the zoom optical system or an aperture value of the diaphragm.

6. The lens device according to claim 5 , further comprising a memory that stores an amount of adjustment of the focal position.

7. The lens device according to claim 5 , wherein as adjustment of the focal position performed by the adjustment control device, only adjustment of the focal position based on movement of the focus optical system is performed if the zoom ratio is at a telephoto end, or only adjustment of the focal position based on movement of the master optical system is performed if the zoom ratio is at a wide-angle end.

8. The lens device according to claim 5 , wherein in accordance with the amount of variation in focal position, the amount of adjustment of the focal position based on the movement of the focus optical system is larger at a position closer to the telephoto end and is smaller at a position closer to the wide-angle end, and the amount of adjustment of the focal position based on the movement of the master optical system is larger at a position closer to the wide-angle end and is smaller at a position closer to the telephoto end.

9. The lens device according to claim 5 , wherein in accordance with the amount of variation in focal position, in a case of an aperture value at which an opening of the diaphragm is minimized, only the adjustment of the focal position based on the movement of the focus optical system is performed, and in a case of an aperture value at which the opening of the diaphragm is maximized, only the adjustment of the focal position based on the movement of the master optical system is performed.

10. The lens device according to claim 5 , wherein in accordance with the amount of variation in focal position, the amount of adjustment of the focal position based on the movement of the focus optical system is larger at an aperture value closer to an aperture value at which the opening of the diaphragm is minimized, and is smaller at an aperture value closer to an aperture value at which the opening of the diaphragm is maximized, and the amount of adjustment of the focal position based on the movement of the master optical system is larger if a size of the opening of the diaphragm is closer to a maximum thereof and is smaller if the size of the opening of the diaphragm is closer to a minimum thereof.

11. A correction method for a lens device having a plurality of lenses that an optical axis is common, the method comprising:
causing a lens moving mechanism to move one or more lenses, which are included in the plurality of lenses, in a direction of an optical axis of the plurality of lenses;
causing a storage section to store a plurality of positions of the plurality of lenses in the direction of the optical axis and a plurality of rotation angles respectively corresponding to the plurality of positions; and
causing a lens rotating mechanism, which can be driven separately from the lens moving mechanism, to rotate at least one lens, which are included in the plurality of lenses, about the optical axis of the lens by a rotation angle corresponding to a position of the lens, which is moved by the lens moving mechanism, in the direction of the optical axis, among the plurality of rotation angles stored in the storage section.

Assignees

• Fujifilm Corp

Inventors

• Shimotsu Shinichi

Classifications

• G02B15/04 Primary

  by changing a part · CPC title

• G02B7/005 Primary

  Motorised alignment · CPC title

• G02B7/16

  Rotatable turrets · CPC title

• G02B7/10

  by relative axial movement of several lenses, e.g. of varifocal objective lens · CPC title

• G02B7/102

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