Drive-condition setting device and drive-condition setting method for optical scanning apparatus

Patent metadata

Field	Value
Publication number	US-2018113298-A1
Application number	US-201715839177-A
Country	US
Kind code	A1
Filing date	Dec 12, 2017
Priority date	Jun 23, 2015
Publication date	Apr 26, 2018
Grant date	—

Abstract

A drive-condition setting device applied to an optical scanning apparatus having a fiber and an actuator that vibrates a distal end of the fiber, the drive-condition setting device detects a scan pattern of the illumination light output from the fiber, measures resonance frequencies in the x direction and the y direction of the fiber, sets a drive frequency and a drive voltage based on the resonance frequencies such that conditional expressions below are satisfied: when fx>fy, fd<fy and Vx≥Vy (1) or fd>fx and Vx≤Vy (2), and when fx≤fy, fd<fx and Vx≤Vy (3) or fd>fy and Vx≥Vy (4) where fd denotes the drive frequency, Vx denotes a maximum voltage of a X direction drive signal, and Vy denotes a maximum voltage of a y direction drive signal.

First claim

1 . A drive-condition setting device applied to an optical scanning apparatus having a fiber and an actuator, the fiber optically guiding illumination light emitted from a light source and radiating the illumination light from its distal end onto an observation target, the actuator vibrating the distal end of the fiber with a predetermined drive frequency in two axial directions including an x direction and a y direction, the drive-condition setting device comprising:
a scan-pattern detector that detects a scan pattern of the illumination light output from the distal end of the fiber; and a controller that measures resonance frequencies in the x direction and the y direction of the fiber and that sets drive conditions of the actuator based on the resonance frequencies and conduct control, wherein the controller sets a target amplitude of the scan pattern and sets a drive frequency and drive voltages such that the scan pattern detected by the scan-pattern detector is within a predetermined range with respect to the target amplitude and such that conditional expressions below are satisfied: when fx>fy,
fd<fy and Vx≥Vy   (1)

or
fd>fx and Vx≤Vy   (2), and

when fx≤fy,
fd<fx and Vx≤Vy   (3)

or
fd>fy and Vx≥Vy   (4)

where fd denotes the drive frequency, fx denotes the resonance frequency in the x direction, fy denotes the resonance frequency in the y direction, Vx denotes a maximum voltage with respect to a drive signal in the x direction, and Vy denotes a maximum voltage with respect to a drive signal in the y direction.

2 . The drive-condition setting device according to claim 1 , wherein when the controller sets the drive frequency and the drive voltage, the controller firstly sets the drive frequency and the drive voltage for a direction in which a voltage value becomes relatively higher between the drive voltage for the x direction and the drive voltage for the y direction, satisfying the conditional expressions (1) to (4), and subsequently sets the drive voltage for a direction in which the voltage value becomes low.

3 . A drive-condition setting device applied to an optical scanning apparatus having a fiber and an actuator, the fiber optically guiding illumination light emitted from a light source and radiating the illumination light from its distal end onto an observation target, the actuator vibrating the distal end of the fiber with a predetermined drive frequency in two axial directions including an x direction and a y direction, the drive-condition setting device comprising:
a controller that measures resonance frequencies in the x direction and the y direction of the fiber and that sets drive conditions based on the resonance frequencies and conducting control, wherein the controller calculates a difference in phase shift amounts between the x direction and the y direction based on a phase shift of a vibration waveform of the fiber with respect to the x direction and a phase shift of a vibration waveform of the fiber with respect to the y direction, and sets a corrected phase difference by correcting a phase difference in the y direction relative to the x direction such that conditional expressions below are satisfied: when fx≤fy,
θ′=θ−|Δθ|  (5), and

when fx>fy,
θ′=θ+|Δθ|  (6)

where fx denotes the resonance frequency in the x direction, fy denotes the resonance frequency in the y direction, θ′ denotes the corrected phase difference, θ denotes the phase difference of a y-direction voltage waveform relative to that of the x direction, and |Δθ| denotes the difference in phase shift amounts between the x direction and the y direction.

4 . A drive-condition setting method applied to an optical scanning apparatus having a fiber and an actuator, the fiber optically guiding illumination light emitted from a light source and radiating the illumination light from its distal end onto an observation target, the actuator vibrating the distal end of the fiber with a predetermined drive frequency in two axial directions including an x direction and a y direction, the drive-condition setting method comprising:
a scan-pattern detecting step of detecting a scan pattern of the illumination light output from the distal end of the fiber; and a controlling step of measuring resonance frequencies in the x direction and the y direction of the fiber, setting drive conditions of the actuator based on the resonance frequencies, and conducting control, wherein the controlling step includes setting a target amplitude of the scan pattern and setting a drive frequency and drive voltages such that the scan pattern detected in the scan-pattern detecting step is within a predetermined range with respect to the target amplitude and such that conditional expressions below are satisfied: when fx>fy,
fd<fy and Vx≥Vy   (1)

or
fd>fx and Vx≤Vy   (2), and

when fx≤fy,
fd<fx and Vx≤Vy   (3)

or
fd>fy and Vx≥Vy   (4)

where fd denotes the drive frequency, fx denotes the resonance frequency in the x direction, fy denotes the resonance frequency in the y direction, Vx denotes a maximum voltage with respect to a drive signal in the x direction, and Vy denotes a maximum voltage with respect to a drive signal in the y direction.

5 . A drive-condition setting method applied to an optical scanning apparatus having a fiber and an actuator, the fiber optically guiding illumination light emitted from a light source and radiating the illumination light from its distal end onto an observation target, the actuator vibrating the distal end of the fiber with a predetermined drive frequency in two axial directions including an x direction and a y direction, the drive-condition setting method comprising:
a controlling step of measuring resonance frequencies in the x direction and the y direction of the fiber, setting drive conditions based on the resonance frequencies, and conducting control, wherein the controlling step includes calculating a difference in phase shift amounts between the x direction and the y direction based on a phase shift of a vibration waveform of the fiber with respect to the x direction and a phase shift of a vibration waveform of the fiber with respect to the y direction, and setting a corrected phase difference by correcting a phase difference in the y direction relative to the x direction such that conditional expressions below are satisfied: when fx≤fy,
θ′=θ−|Δθ|  (5), and

when fx>fy,
θ′=θ+|Δθ|  (6)

where fx denotes the resonance frequency in the x direction, fy denotes the resonance frequency in the y direction, θ′ denotes the corrected phase difference, θ denotes the phase difference of a y-direction voltage waveform relative to that of the x direction, and |Δθ| denotes the difference in phase shift amounts between the x direction and the y direction.

Assignees

• Olympus Corp

Inventors

• Shimamoto Atsuyoshi
• Yamada Masashi
• KOSHIKA Soichiro

Classifications

• G02B23/2469

  using optical fibres · CPC title

• G02B26/101 Primary

  with both horizontal and vertical deflecting means, e.g. raster or XY scanners (colour television using laser beams scanning a display screen H04N9/3129) · CPC title

• A61B1/00172

  with means for scanning · CPC title

• A61B1/00006

  of control signals · CPC title

• G02B26/103

  having movable or deformable optical fibres, light guides or waveguides as scanning elements (light guides per se G02B6/00) · CPC title