Lens barrel and imaging device with element and elastic body for producing vibration wave

Patent metadata

Field	Value
Publication number	US-11757381-B2
Application number	US-202217980762-A
Country	US
Kind code	B2
Filing date	Nov 4, 2022
Priority date	Oct 18, 2017
Publication date	Sep 12, 2023
Grant date	Sep 12, 2023

Abstract

A lens barrel includes an element displaced by application of voltage; an elastic body having a contact surface coming into contact with the element, a drive surface to produce a vibration wave by displacement of the element, and a plurality of grooves; a moving element come into contact with the drive surface and rotated by the vibration wave; an annular ring rotated by rotating of the moving element; and a lens moved in an optical axis direction by rotating of the annular ring; wherein the element mainly contains a material having potassium sodium niobate, potassium niobate, sodium niobate, or barium titanate, wherein a value of [(T/B)÷W] is in a range of 0.84 to 1.94, where T represents a depth of the groove, B represents a distance from a bottom part of the groove to the contact surface, and W represents a radial width of the elastic body.

First claim

What is claimed is:

1. A lens barrel comprising:
an element configured to be displaced by application of voltage;
an elastic body having a contact surface coming into contact with the element, a drive surface to produce a vibration wave by displacement of the element, and a plurality of grooves;
a moving element configured to come into contact with the drive surface and rotate by the vibration wave;
an annular ring configured to rotate by rotating of the moving element; and
a lens configured to move in a direction of an optical axis by rotating of the annular ring;
wherein the element is made of a material having potassium sodium niobate, potassium niobate, sodium niobate, or barium titanate as a principal component,
wherein a value of [(T/B)÷W] is in a range of 0.84 to 1.94, where T represents a depth of the groove, B represents a distance from a bottom part of the groove to the contact surface, and W represents a radial width of the elastic body.

2. The lens barrel according to claim 1 , wherein
the element has a thickness in a direction of a depth of the groove.

3. The lens barrel according to claim 1 , wherein
the value of [(T/B)÷W] is in a range of 0.84 to 1.02.

4. The lens barrel according to claim 1 , wherein
the value of [(T/B)÷W] is in a range of 1.02 to 1.94.

5. The lens barrel according to claim 1 , the lens barrel comprising:
a drive circuit configured to provide a drive signal that fluctuates repeatedly to a vibration wave motor having the element and the elastic body, wherein
when starting the vibration wave motor under a speed zero up to a speed larger than zero, the drive circuit changes a frequency change rate of the drive signal on a basis of the value of [(T/B)÷W].

6. The lens barrel according to claim 5 , wherein
the drive circuit is set the frequency change rate to 0.5 kHz/msec or lower when the value of [(T/B)÷W] is in a range of 0.84 to 1.02, and
is set the frequency change rate to 0.25 kHz/msec or lower when the value of [(T/B)÷W] is in a range of 1.02 to 1.94.

7. The lens barrel according to claim 1 , wherein
the element is an electromechanical conversion element configured to convert electrical energy to mechanical energy.

8. An imaging device comprising:
the lens barrel according to claim 1 ; and
a camera body.

Assignees

• Nikon Corp

Inventors

• Ashizawa Takatoshi

Classifications

• H02N2/163 Primary

  Motors with ring stator · CPC title

• H02N2/12 Primary

  Constructional details · CPC title

• G02B7/10 Primary

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

• H02N2/0065

  Friction interface (friction linings F16D69/00) · CPC title

• H10N30/8536

  Alkaline earth metal based oxides, e.g. barium titanates · CPC title