Optical scanning apparatus

Patent metadata

Field	Value
Publication number	US-2017311776-A1
Application number	US-201715654759-A
Country	US
Kind code	A1
Filing date	Jul 20, 2017
Priority date	Jan 23, 2015
Publication date	Nov 2, 2017
Grant date	—

Abstract

An optical scanning endoscope apparatus includes: an illumination optical fiber that emits light from a tip part oscillatably supported; an actuator that drives the tip part of the illumination optical fiber; and a signal generator that generates, with respect to the actuator, a drive signal for causing the tip part of the illumination optical fiber to spiral scan. The signal generator generates the drive signal which includes: an amplitude expansion period for expanding the amplitude of the drive signal of the fiber from substantially 0 to a maximum value; and an amplitude contraction period for contracting the amplitude of the drive signal from the maximum value to substantially 0, the drive signal having an envelope that smoothly continues, with a gradient of substantially 0, across a border between the periods, with the longer one of the periods being defined as an effective scanning period.

First claim

1 . An optical scanning apparatus, comprising:
a fiber that emits light from a tip part oscillatably supported; an actuator that drives the tip part of the fiber; and a signal generator that generates, with respect to the actuator, a drive signal for causing the tip part of the fiber to spiral scan, wherein: the signal generator generates a drive signal having, in one scanning period, a first period and a second period different in length from the first period, the first period expanding the amplitude of the drive signal of the fiber from substantially 0 to a maximum value, the second period contracting the amplitude of the drive signal from the maximum value to substantially 0; the drive signal has an envelope that smoothly continues, with a gradient of substantially 0, across a border between the first period and the second period; and a longer one of the first period and the second period is defined as an effective scanning period.

2 . The optical scanning apparatus according to claim 1 , wherein the tip part of the fiber is driven at a drive frequency different from a resonance frequency.

3 . The optical scanning period according to claim 1 , wherein the envelope of the drive signal in the first period and the envelope of the drive signal in the second period each form part of sinusoidal waves mutually different in cycle.

4 . The optical scanning apparatus according to claim 1 , satisfying:

0.1
≤

n
1

n
1

+

n
2

≤
0.9

,

(
1
)

where n 1 represents the number of laps in a spiral scan of the fiber during the first period, and n 2 represents the number of laps in a spiral scan of the fiber during the second period.

5 . The optical scanning apparatus according to claim 4 , wherein the number of laps n 1 and the number of laps n 2 satisfy, with f r representing a frame rate of the spiral scan:

f
r

≥
25

;




and

(
2
)

0.2
≤

n
1

n
1

+

n
2

≤

0.8
.

(
3
)

6 . The optical scanning apparatus according to claim 4 , wherein the number of laps n 1 and the number of laps n 2 satisfy, with f r representing a frame rate of the spiral scan:

f
r

≥
60

:


and

(
4
)

0.4
≤

n
1

n
1

+

n
2

≤

0.6
.

(
5
)

7 . The optical scanning apparatus according to claim 3 , satisfying:

f

m



1

=

f
d

2




n
1




and

(
6
)

1

2

Assignees

• Olympus Corp

Inventors

• Shimamoto Atsuyoshi

Classifications

• A61B1/000095

  for image enhancement · CPC title

• G02B23/2469 Primary

  using optical fibres · CPC title

• A61B1/00013 Primary

  using optical means · CPC title

• A61B1/07

  using light-conductive means, e.g. optical fibres · CPC title

• A61B1/00009

  of image signals during a use of endoscope · CPC title