Abstract: A lens barrel includes first and second yokes each having a length in an optical axis direction, a third yoke that has a length in the optical axis direction and is disposed between the first and second yokes, first and second magnets disposed on the first and second yokes, respectively, a coil that is penetrated by the third yoke and is movable in the optical axis direction by magnetic forces of the first and second magnets, and a lens holding frame that holds a lens and is movable together with the coil in the optical axis direction, wherein a first plane including a first side surface, which is farther from the third yoke, of the first yoke intersects with a second plane including a second side surface, which is farther from the third yoke, of the second yoke.

Abstract: To provide a small-sized voice coil motor, the voice coil motor includes a first yoke and a second yoke each having a length in a first direction, a third yoke that has a length in the first direction and is disposed between the first yoke and the second yoke, a first magnet disposed on the first yoke, a second magnet disposed on the second yoke, and a coil that is penetrated by the third yoke and is movable in the first direction by magnetic forces of the first magnet and the second magnet, wherein the coil includes a first section in which a winding wire is linearly wound and a second section in which the wiring wire is wound in an arc shape.

Abstract: A lens barrel includes: an electromechanical conversion element; an elastic body having a joining surface, a drive surface, and grooves; a motion member rotating by vibration wave of the drive surface; a rotating ring having a recess part and rotating by rotation of the motion member; a moving ring engaged to the recess part and moving to an optical axis direction by rotation of the rotating ring; and a lens held in the moving ring; wherein the element is made of a material having sodium potassium niobate, potassium niobate, sodium niobate or barium titanate, wherein a value of T/(B+C) is within a range of from 1.3 to 2.8 when: length from the drive surface to a base unit of the groove is defined as T; length from the base unit of the groove to the joining surface is defined as B; and thickness of the element is defined as C.

Abstract: A lens barrel includes: an electromechanical conversion element; an elastic body having a joining surface, a drive surface, and grooves; a motion member rotating by vibration wave of the drive surface; a rotating ring having a recess part and rotating by rotation of the motion member; a moving ring engaged to the recess part and moving to an optical axis direction by rotation of the rotating ring; and a lens held in the moving ring; wherein the element is made of a material having sodium potassium niobate, potassium niobate, sodium niobate or barium titanate, wherein a value of T/(B+C) is within a range of from 1.3 to 2.8 when: length from the drive surface to a base unit of the groove is defined as T; length from the base unit of the groove to the joining surface is defined as B; and thickness of the element is defined as C.

Abstract: A vibration wave motor comprises: an electromechanical conversion element; an elastic body which has a drive surface on which a vibration wave is generated due to vibration of the electromechanical conversion element; and a relative motion member which makes contact with the drive surface of the elastic body and is configured to rotationally drive by the vibration wave, the electromechanical conversion element having a density of from 4.2 to 6.0×103 kg/m3, a plurality of grooves being provided on the drive surface side of the elastic body, and a value of T/(B+C) being within a range of from 1.3 to 2.8 when: depth of at least one groove of the plurality of grooves is defined as T; thickness from a base unit of the groove to a first surface is defined as B; and thickness of the electromechanical conversion element is defined as C.

Abstract: A vibration wave motor comprises: an electromechanical conversion element; an elastic body which has a drive surface on which a vibration wave is generated due to vibration of the electromechanical conversion element; and a relative motion member which makes contact with the drive surface of the elastic body and is configured to rotationally drive by the vibration wave, the electromechanical conversion element having a density of from 4.2 to 6.0×103 kg/m3, a plurality of grooves being provided on the drive surface side of the elastic body, and a value of T/(B+C) being within a range of from 1.3 to 2.8 when: depth of at least one groove of the plurality of grooves is defined as T; thickness from a base unit of the groove to a first surface is defined as B; and thickness of the electromechanical conversion element is defined as C.