WO2018207356A1

WO2018207356A1 - Optical scanning device

Info

Publication number: WO2018207356A1
Application number: PCT/JP2017/018056
Authority: WO
Inventors: 健寛三木
Original assignee: オリンパス株式会社
Priority date: 2017-05-12
Filing date: 2017-05-12
Publication date: 2018-11-15

Abstract

An optical scanning device (1) comprises: a lighting system (6); a scanning module (5) for scanning illumination light that enters the lighting system (6) from a light source (4); a reflector (7) that reflects, in a direction parallel to the optical axis, the illumination light emitted in a direction parallel to the optical axis from the lighting system (6); a light receiving unit (8) that receives the illumination light reflected by the reflector (7) via the optical path for the illumination light in the lighting system (6); a position adjusting unit (9) that adjusts the relative position between the scanning module (5) and the lighting system (6) along the directions parallel to and perpendicular to the optical axis of the lighting system (6); and a control unit (10) that controls the position adjusting unit (9) on the basis of the amount of light received by the light receiving unit (8).

Description

Optical scanning device

The present invention relates to an optical scanning device.

Conventionally, there has been known an optical scanning endoscope that scans excitation light irradiated on a subject from the tip of the optical fiber by vibrating the tip of the optical fiber, and receives and images fluorescence from the irradiation position of the illumination light. (For example, refer to Patent Document 1). In Patent Document 1, a confocal fluorescence image is acquired by providing an objective optical system in front of the tip of an optical fiber. That is, the tip of the optical fiber is disposed at the front focal point of the objective optical system, and only the fluorescence at a position optically conjugate with the tip of the optical fiber is detected through the objective optical system and the optical fiber. Yes.

Patent Document 1 discloses that a chart image is acquired for calibration for evaluating image distortion and resolution. In order to acquire a clear chart image, the objective optical system needs to be focused on the chart. In Patent Document 1, parallel light is irradiated from behind to a chart disposed in front of an optical fiber, light transmitted through the chart is received through the optical fiber, and the position where the amount of received light is maximized is determined as the focal point of the objective optical system. Is detected as a position that fits the chart.

Japanese Patent Laid-Open No. 2015-20032

In order to control the spot diameter of light irradiated to the subject via the objective optical system, it is necessary to accurately adjust the relative position between the optical fiber and the objective optical system. The moving mechanism disclosed in Patent Document 1 can adjust the position of the objective optical system in the optical axis direction, but adjusts the relative position between the optical fiber and the objective optical system in the direction intersecting the optical axis. I can't.

In Patent Document 1, since a light source is provided outside, even if the relative position between the optical fiber and the objective optical system is deviated from the ideal position in the optical axis direction, Light easily enters the optical fiber. Therefore, the amount of change in the amount of received light with respect to the amount of change in the optical axis direction of the relative position between the optical fiber and the objective optical system becomes small. Therefore, it is difficult to accurately detect the relative position of the optical fiber and the objective optical system in the optical axis direction based on the amount of received light, and it is difficult to perform position adjustment with high accuracy.

The present invention has been made in view of the above-described circumstances, and can adjust the relative position in the direction intersecting the optical axis of the illumination optical system and the scanning unit, and adjust the relative position in the optical axis direction. An object of the present invention is to provide an optical scanning device capable of performing the above with high accuracy.

In order to achieve the above object, the present invention provides the following means.
According to a first aspect of the present invention, an illumination optical system that irradiates a subject with illumination light from a light source in a spot shape, and illumination light that enters the illumination optical system from the light source intersects the optical axis of the illumination optical system. A scanning section that scans in a direction, and is arranged to face the illumination optical system, and the illumination light emitted from the illumination optical system in parallel to the optical axis is parallel to the optical axis toward the illumination optical system. A reflecting part that reflects in the direction; a light receiving part that receives the illumination light reflected by the reflecting part through an optical path of the illumination light in the illumination optical system; and a parallel to the optical axis of the illumination optical system. A position adjusting unit that adjusts the relative position of the scanning unit and the illumination optical system in a normal direction and a vertical direction, and a control that controls the position adjusting unit based on the amount of received illumination light received by the light receiving unit And optical scanning It is the location.

According to the first aspect, the illumination light emitted from the illumination optical system is reflected by the reflection unit, and returns to the illumination optical system through the same optical path as the illumination light from the illumination optical system to the reflection unit. The illuminated light is received by the light receiving unit.
Here, the emission direction of the illumination light emitted from the illumination optical system changes according to the relative position in the direction (XY direction) intersecting the optical axis of the scanning unit and the illumination optical system, and is emitted from the illumination optical system. The divergence angle (or convergence angle) of the illumination light changes according to the relative position of the scanning unit and the illumination optical system in the optical axis direction (Z direction). The reflecting section is configured to turn a light ray parallel to the optical axis of the illumination optical system 180 ° and reflect a light ray inclined to the optical axis in a direction inclined to the optical axis.

As described above, the direction and divergence angle (or convergence angle) of the illumination light irradiated from the illumination optical system to the reflection unit are changed according to the relative positions of the scanning unit and the illumination optical system in the XY direction and the Z direction, and reflected. The direction and divergence angle (convergence angle) of the illumination light reflected by the part also vary. Therefore, the efficiency with which the illumination light emitted from the illumination optical system returns to the illumination optical system via the reflection unit, following the same optical path from the illumination optical system to the reflection unit is as follows. It fluctuates sensitively not only to the relative position in the XY direction but also to the change in the relative position in the Z direction. Therefore, the control unit detects an accurate relative position between the scanning unit and the illumination optical system based on the amount of illumination light received by the light receiving unit, and determines the relative position between the scanning unit and the illumination optical system in the XY direction. In addition to the Z direction, the position adjustment unit can adjust the position with high accuracy.

According to a second aspect of the present invention, an illumination optical system that irradiates a subject with illumination light from a light source in a spot shape, and illumination light that enters the illumination optical system from the light source intersects the optical axis of the illumination optical system. A scanning section that scans in a direction, and is arranged to face the illumination optical system, and the illumination light emitted from the illumination optical system in parallel to the optical axis is parallel to the optical axis toward the illumination optical system. A reflecting part that reflects in the direction, a light receiving part that receives the illumination light reflected by the reflecting part in the vicinity of the illumination optical system, and a direction parallel to and perpendicular to the optical axis of the illumination optical system Optical scanning comprising: a position adjusting unit that adjusts a relative position between the scanning unit and the illumination optical system in the case; and a control unit that controls the position adjusting unit based on a received light amount of the illumination light received by the light receiving unit. Device.

According to the second aspect, the illumination light emitted from the illumination optical system is reflected by the reflection unit, and reaches the light receiving unit by following substantially the same optical path as the illumination light from the illumination optical system to the reflection unit. The illuminated light is received by the light receiving unit. The efficiency with which the illumination light emitted from the illumination optical system reaches the light receiving unit through the reflection unit, following the optical path from the illumination optical system to the reflection unit, is substantially the same between the scanning unit and the illumination optical system. It fluctuates sensitively not only to the relative position in the XY direction but also to the change in the relative position in the Z direction. Therefore, the control unit detects an accurate relative position between the scanning unit and the illumination optical system based on the amount of illumination light received by the light receiving unit, and determines the relative position between the scanning unit and the illumination optical system in the XY direction. In addition to the Z direction, the position adjustment unit can adjust the position with high accuracy.

In the first and second aspects, the illumination optical system has a positive refractive power for converting the illumination light incident as a divergent light beam into a parallel light beam, and the control unit is received by the light receiving unit. The position adjustment unit may be controlled so that the illumination optical system is arranged at a position where the amount of received illumination light is maximized.
By doing in this way, the relative position of an illumination optical system and a scanning part is adjusted so that illumination light may be inject | emitted as a parallel light beam from an illumination optical system. As a result, illumination light having a small spot diameter can be irradiated even on a subject far from the illumination optical system.

In the first and second aspects, the scanning unit may include a lens system closest to the illumination optical system.
Thus, a space can be secured between the scanning unit and the illumination optical system by optically coupling the scanning unit with the illumination optical system via the lens system. In addition, the aberration of the illumination optical system can be corrected by the lens system provided in the scanning unit.

According to the present invention, the relative position in the direction intersecting the optical axis of the illumination optical system and the scanning unit can be adjusted, and the relative position in the optical axis direction can be adjusted with high accuracy. Play.

1 is an overall configuration diagram of an optical scanning device and an optical scanning endoscope according to a first embodiment of the present invention. It is a figure which shows the structural example of the reflection part in the optical scanning device of FIG. It is a figure which shows the other structural example of the reflection part in the optical scanning device of FIG. It is a figure which shows the other structural example of the reflection part in the optical scanning device of FIG. It is a figure which shows the other structural example of the reflection part in the optical scanning device of FIG. 3 is a flowchart illustrating a position adjustment method for a scanning unit and an illumination optical system in the optical scanning device of FIG. 1. 4 is a received light amount distribution in the X and Y directions of the reflected laser beam acquired in step S2 of FIG. It is a figure explaining the relationship between the relative position of the X-Y direction of a scanning part and an illumination optical system, and the light quantity of the reflected laser beam which injects into the front-end | tip of the optical fiber for illumination. 4 is a received light amount distribution in the Z direction of the reflected laser light acquired in step S4 of FIG. It is a figure explaining the relationship between the relative position of the Z direction of a scanning part and an illumination optical system, and the light quantity of the reflected laser beam which injects into the front-end | tip of the optical fiber for illumination. It is a whole block diagram of the optical scanning device and optical scanning endoscope which concern on the 2nd Embodiment of this invention. It is a figure explaining the positional relationship of an illumination optical system and a reflective surface. It is a block diagram of the modification of the position adjustment part in the optical scanning device which concerns on 1st and 2nd embodiment. It is a block diagram of the modification of the scanning part in the optical scanning device which concerns on 1st and 2nd embodiment.

(First embodiment)
An optical scanning device 1 according to a first embodiment of the present invention and an optical scanning endoscope 100 including the same will be described with reference to FIGS.
As shown in FIG. 1, the optical scanning endoscope 100 according to the present embodiment includes a long insertion portion 2 that can be inserted into the body, a housing 3 connected to the proximal end of the insertion portion 2, An optical scanning device 1 that emits laser light (illumination light) L from the distal end of the insertion portion 2 and scans the laser light L is provided.
The optical scanning endoscope 100 scans a laser beam L on a subject facing the distal end of the insertion unit 2 and observes light (for example, reflected light of the laser beam L or laser beam) generated on the subject by irradiation with the laser beam L. (Fluorescence excited by L) is observed.

The optical scanning device 1 includes a laser light source (light source) 4, a scanning unit 5 that scans the laser light L output from the laser light source 4, and the laser beam L that is scanned by the scanning unit 5 faces the tip of the insertion unit 2. The illumination optical system 6 that emits light toward the subject and collects light from the subject, the reflection unit 7 that is disposed opposite to the illumination optical system 6 and reflects the laser light L, and the light collected by the illumination optical system 6 Is received through the optical path of the laser light L in the illumination optical system 6 and the scanning unit 5, a position adjustment unit 9 that adjusts the position of the illumination optical system 6, and light reception by the light receiving unit 8. And a control unit 10 that controls the position adjustment unit 9 based on the amount.

The laser light source 4 is a semiconductor light source such as an LD (laser diode) and is provided in the housing 3.
The scanning unit 5 includes an optical fiber 51 for illumination that is disposed along the longitudinal direction in the insertion unit 2 and guides the laser light L from the laser light source 4 to the distal end of the insertion unit 2, and a distal end 51 a of the optical fiber 51. And an actuator 52 that vibrates in the radial direction of the optical fiber 51.
The proximal end of the optical fiber 51 is connected to the laser light source 4, and the distal end 51 a of the optical fiber 51 is disposed on the proximal end side with respect to the illumination optical system 6.

The actuator 52 is, for example, a piezoelectric type that includes a piezoelectric element fixed to the outer peripheral surface of the optical fiber 51 and vibrates the tip 51 a by expanding and contracting the piezoelectric element in the longitudinal direction of the optical fiber 51. Alternatively, the actuator 52 includes a magnetic body fixed to the outer peripheral surface of the optical fiber 51 and an electromagnetic coil, and vibrates the tip 51a by applying a radial magnetic field of the optical fiber 51 from the electromagnetic coil to the magnetic body. It may be electromagnetic.

The illumination optical system 6 has a positive refractive power as a whole, and is provided at the tip of the insertion portion 2. In FIG. 1, the illumination optical system 6 is shown as a single lens, but the illumination optical system 6 may be composed of a plurality of lenses. The illumination optical system 6 is disposed in a recess formed in the distal end surface of the insertion portion 2, and is supported by a holding member 91 of a position adjustment portion 9 described later so as to be movable in a direction parallel to and perpendicular to the optical axis. ing. The illumination optical system 6 is roughly aligned with the tip 51a of the optical fiber 51 so that the front focal point of the illumination optical system 6 is positioned at or near the tip 51a of the optical fiber 51 in a stationary state. Yes. The illumination optical system 6 may include a flat plate or the like that transmits light on the bottom surface of the recess facing the tip 51 a of the optical fiber 51.

When the position of the front focal point F of the illumination optical system 6 coincides with the position of the tip 51a of the optical fiber 51 (see the lower diagram in FIG. 7), the laser light L emitted as a divergent light beam from the tip 51a of the optical fiber 51. Is converted into a parallel light beam by the illumination optical system 6, and the parallel light beam is emitted from the illumination optical system 6. In this state, the illumination optical system 6 is in focus at infinity, and the subject is irradiated with the laser light L from the illumination optical system 6 in a spot shape. In addition, since a laser beam L having a small spot diameter is also irradiated to a subject that is far from the distal end of the insertion portion 2, a high resolving power can be obtained. Further, in this state, as will be described later, the laser light L (reflected laser light L ′) reflected by the reflecting portion 7 returns to the illumination optical system 6 and enters the tip 51a of the optical fiber 51. The laser light L is guided in the opposite direction.

The reflecting unit 7 is used when adjusting the relative position between the scanning unit 5 and the illumination optical system 6 so that the position of the front focal point F of the illumination optical system 6 coincides with the position of the tip 51a of the optical fiber 51. The The reflection unit 7 has a reflection surface 7 a that reflects the laser light L, and is disposed in front of the distal end of the insertion unit 2 so that the reflection surface 7 a faces the illumination optical system 6. For example, the reflection unit 7 is configured to be detachable from the distal end portion of the insertion portion 2, and is parallel to the optical axis of the laser light L emitted from the illumination optical system 6 while being attached to the distal end portion of the insertion portion 2. The reflection surface 7a is configured to bend the light rays by 180 °.

2A to 2D show a configuration example of the reflection unit 7.
2A is provided on the bottom surface of a columnar recess 3a that is formed in the housing 3 and the distal end of the insertion portion 2 is fitted in the longitudinal direction. The reflection surface 7a is a flat surface perpendicular to the longitudinal direction of the recess 3a, and is disposed at a position spaced from the tip of the insertion portion 2 fitted in the recess 3a in the optical axis direction of the illumination optical system 6. . The vertical relationship between the optical axis of the illumination optical system 6 and the reflecting surface 7a is ensured by fitting the recess 3a with the tip of the insertion portion 2.

2B is provided at one end of a cylindrical cap 12 that covers the distal end portion of the insertion portion 2. The cap 12 is opened at the other end, and the cap 12 and the distal end portion of the insertion portion 2 inserted into the cap 12 from the opening at the other end are fitted with each other. The reflecting surface 7 a is a flat surface perpendicular to the longitudinal direction of the cap 12, and is disposed at a position spaced from the distal end of the insertion portion 2 fitted in the cap 12 in the optical axis direction of the illumination optical system 6. . The vertical relationship between the optical axis of the illumination optical system 6 and the reflecting surface 7a is secured by fitting the cap 12 with the distal end portion of the insertion portion 2.

The reflective surface 7a in FIGS. 2A and 2B is a flat surface and is disposed at a position spaced from the illumination optical system 6. However, the reflective surface 7a has illumination optics as shown in FIGS. 2C and 2D. It may be arranged without a gap between the system 6 and may be a non-flat surface.
2C is a member disposed adjacent to the distal end surface of the insertion portion 2, and has a concave spherical shape complementary to the distal end surface of the illumination optical system 6, and the distal end surface of the illumination optical system 6. It has a reflective surface 7a arranged in contact.
2D includes the tip surface of the illumination optical system 6. That is, the tip surface of the illumination optical system 6 plays the role of the reflecting surface 7a.

The light receiving unit 8 includes an optical fiber 81 that receives the reflected laser beam L ′ via the optical fiber 51, and a photodetector 82 that detects the reflected laser beam L ′ received by the optical fiber 81.
The optical fiber 81 branches from the optical fiber 51 between the laser light source 4 and the actuator 52, separates the reflected laser light L ′ guided through the optical fiber 51 from the laser light L, and guides it to the photodetector 82. To do.
The photodetector 82 photoelectrically converts the reflected laser light L ′ incident from the optical fiber 81 to generate an electrical signal corresponding to the received light amount of the reflected laser light L ′, and uses the electrical signal as received light amount information as the control unit 10. Send to.

The position adjusting unit 9 includes a holding member 91 that holds the illumination optical system 6 and an XYZ driving unit 92 such as a three-axis motor that moves the holding member 91 in the X, Y, and Z directions. The X direction and the Y direction are directions orthogonal to each other and orthogonal to the optical axis of the illumination optical system 6, and the Z direction is a direction parallel to the optical axis of the illumination optical system 6. The XYZ driving unit 92 transmits the X, Y, and Z positions of the illumination optical system 6 to the control unit 10 and moves the illumination optical system 6 in the X, Y, and Z directions according to a control signal from the control unit 10.

The control unit 10 sequentially adjusts the position adjustment of the illumination optical system 6 in the XY direction and the position adjustment in the Z direction so that the amount of the reflected laser light L ′ received by the light receiving unit 8 is maximized. 9 is executed.
In the present invention, since the position in the XY direction of the illumination optical system 6 affects the adjustment in the Z direction, the position adjustment in the Z direction is performed after the position adjustment in the XY direction is performed. In order to increase the accuracy of the adjustment, the position adjustment in the Z direction may be executed after the position adjustment in the XY direction, and then the position adjustment in the XY direction and the position adjustment in the Z direction may be repeated a plurality of times in the same order.

Next, the position adjustment process of the illumination optical system 6 by the control unit 10 will be described. The position adjustment process is executed in a state where the tip 5a of the optical fiber 51 is stationary using the reflection unit 7 instead of the subject. The position adjustment process is executed, for example, before the observation of the subject by the optical scanning endoscope 100 is started.
As shown in FIG. 3, the control unit 10 starts outputting the laser light L from the laser light source 4 (step S1).

Next, the control unit 10 controls the position adjusting unit 9 so as to move the illumination optical system 6 two-dimensionally in the X direction and the Y direction, and while the illumination optical system 6 is moving, the reflected laser beam L ′. Detection and transmission of received light amount information are repeatedly executed by the photodetector 82. Thereby, as shown in FIG. 4, the control unit 10 acquires the received light amount distribution of the reflected laser light L ′ in the XY directions (step S2).
Next, the control unit 10 controls the position adjustment unit 9 to move the illumination optical system 6 to the XY position where the received light amount is maximum in the received light amount distribution in the XY directions (step S3).

As shown in FIG. 4, when the optical axis A of the illumination optical system 6 and the optical axis of the optical fiber 51 are aligned, the received light amount of the reflected laser light L ′ becomes maximum, and the optical axis A of the illumination optical system 6 is obtained. And the optical axis of the optical fiber 51 are larger in the XY direction, the received light amount of the reflected laser light L ′ decreases. This is illustrated by FIG. That is, when the optical axis A of the illumination optical system 6 and the optical axis of the optical fiber 51 are aligned in a straight line (see the lower diagram in FIG. 5), the reflected laser light L ′ from the reflecting surface 7a is converted into the optical axis. The optical fiber 51 returns to the tip 5a along A. On the other hand, when the optical axis A of the illumination optical system 6 and the optical axis of the optical fiber 51 are shifted in the XY direction (see the upper diagram of FIG. 5), the optical axis 51 is inclined with respect to the optical axis of the optical fiber 51. As the laser light L is emitted from the illumination optical system 6, the reflected laser light L ′ passing outside the tip 51a of the optical fiber 51 increases.

Therefore, by arranging the illumination optical system 6 at the XY position where the received light amount is maximum in the received light amount distribution in the XY directions, the optical axis A of the illumination optical system 6 is aligned with the optical axis of the optical fiber 51. The scanning unit 5 and the illumination optical system 6 can be aligned. Thereby, the position adjustment of the illumination optical system 6 in the XY directions is completed.

Next, the control unit 10 controls the position adjustment unit 9 so as to move the illumination optical system 6 one-dimensionally in the Z direction, and detects the reflected laser light L ′ and moves the illumination optical system 6. The photodetector 82 is repeatedly executed to transmit the received light amount information. As a result, the control unit 10 acquires the received light amount distribution of the reflected laser light L ′ in the Z direction as shown in FIG. 6 (step S4).
Next, the control unit 10 controls the position adjustment unit 9 to move the illumination optical system 6 to the Z position where the received light amount is maximum in the received light amount distribution in the Z direction (step S5).

As indicated by a solid line in FIG. 6, when the front focal point F of the illumination optical system 6 is coincident with the tip 51 a of the optical fiber 51, the amount of received reflected laser light L ′ is maximized, and the front side of the illumination optical system 6. The greater the amount of deviation in the Z direction between the focal point F and the tip 51a of the optical fiber 51, the smaller the amount of received reflected laser light L '. As shown in FIG. 7, when the position of the front focal point F of the illumination optical system 6 coincides with the position of the tip 51a of the optical fiber 51 (see the lower diagram of FIG. 7), the reflecting surface. While all of the reflected laser light L ′ from 7a returns to the tip 5a of the optical fiber 51 along the optical axis A, the position of the front focal point F of the illumination optical system 6 and the position of the tip 51a of the optical fiber 51 are different. When shifted in the Z direction (see the upper diagram of FIG. 7), the laser light L emitted from the illumination optical system 6 has a divergence angle or a convergence angle, so that the outside of the tip 51a of the optical fiber 51 is outside. This is because the reflected laser beam L ′ passing therethrough increases.
The broken lines in FIG. 6 indicate changes in the amount of received light when parallel light is incident on the illumination optical system 6 from the front of the illumination optical system 6 as in Patent Document 1.

Therefore, the position of the front focal point F of the illumination optical system 6 coincides with the position of the tip 51a of the optical fiber 51 by arranging the illumination optical system 6 at the Z position where the received light amount is maximum in the received light amount distribution in the Z direction. As described above, the alignment between the scanning unit 5 and the illumination optical system 6 can be performed. Thereby, the position adjustment of the illumination optical system 6 in the Z direction is completed.

In addition, such a control part 10 is implement | achieved as a control program run by a computer, for example. Specifically, the housing 3 contains a processor such as a central processing unit (CPU), a main storage device such as a RAM, and an auxiliary storage device such as a hard disk drive. The auxiliary storage device stores a control program for causing the processor to execute the above-described position adjustment processing of the control unit 10. The control program is loaded from the auxiliary storage device to the main storage device, and the processor executes processing according to the control program, thereby realizing the function of the control unit 10.

Thus, according to the present embodiment, the efficiency with which the laser light L emitted from the tip 51a of the optical fiber 51 returns to the tip 51a through the reflecting surface 7a and following the same optical path as the laser light L is: It changes sensitively with respect to a change in the relative position between the tip 51a of the optical fiber 51 and the front focal point F of the illumination optical system 6, and the position of the tip 51a of the optical fiber 51 and the position of the front focal point F of the illumination optical system 6 change. The amount of received reflected laser light L ′ changes sharply with respect to the deviation. Therefore, based on the received light amount of the reflected laser beam L ′, the scanning unit 5 and the illumination optical system 6 are arranged so that the position of the tip 51a of the optical fiber 51 and the position of the front focal point F of the illumination optical system 6 are exactly matched. There is an advantage that the relative position can be adjusted with high accuracy.

(Second Embodiment)
Next, an optical scanning device 20 and an optical scanning endoscope 101 according to a second embodiment of the present invention will be described with reference to FIGS.
In the present embodiment, a configuration different from that of the first embodiment will be described, and a configuration common to the first embodiment will be denoted by the same reference numeral and description thereof will be omitted.
The optical scanning device 20 and the optical scanning endoscope 101 according to the present embodiment are different from the first embodiment in the configuration and arrangement of the light receiving unit 80.

As shown in FIG. 8, the optical scanning endoscope 101 according to the present embodiment includes an insertion portion 2, a housing 3, and an optical scanning device 20.
The optical scanning device 20 includes a laser light source 4, a scanning unit 5, an illumination optical system 6, a reflecting unit 7, a light receiving unit 80 that receives the reflected laser light L ′ from the reflecting unit 7, and a position adjusting unit 9. The control unit 10 is provided.

The light receiving unit 80 includes a light receiving optical fiber 83 disposed around the illumination optical system 6 and a photodetector 82.
The optical fiber 83 is disposed in the insertion section 2 along the longitudinal direction of the insertion section 2, and the optical fiber 83 is disposed at the distal end of the insertion section 2 so as to be positioned in the vicinity of the illumination optical system 6. The base end of 83 is connected to the photodetector 82. The reflected laser light L ′ from the reflecting surface 7 a enters the tip of the optical fiber 83, is guided to the photodetector 82 by the optical fiber 83, and is detected by the photodetector 82. Although only one optical fiber 83 may be provided, a plurality of optical fibers 83 are arranged in the circumferential direction of the illumination optical system 6 and connected to a common photodetector 82, and reflected lasers received by the plurality of optical fibers 83. The light L ′ may be configured to be detected by the photodetector 82.

FIG. 9 shows the arrangement of the reflecting surface 7 a with respect to the illumination optical system 6 during the position adjustment process by the control unit 10. The reflecting surface 7 a is disposed at a position that satisfies the following expression (1) with respect to the illumination optical system 6.
D ≧ f (H + P) / 2P (1)

In Expression (1), D is the distance between the front end surface of the illumination optical system 6 and the reflecting surface 7a in the Z direction, and H is the distance of the illumination optical system 6 in the direction orthogonal to the optical axis A of the illumination optical system 6. The distance between the optical axis A and the optical axis at the tip of the optical fiber 83 for light reception, f is the focal length of the illumination optical system 6, and P is the optical axis A of the illumination optical system 6 in the XY directions and the illumination This is the maximum allowable deviation from the optical axis of the optical fiber 51 for use. The larger the Δp, the larger the spot diameter of the laser light L irradiated to the subject from the illumination optical system 6 and the lower the resolving power. Therefore, in consideration of the illumination distance between the illumination optical system 6 and the subject when observing the subject, the maximum deviation amount P is set so that the spot diameter of the laser light L on the subject becomes a size suitable for practical use. For example, it is set experimentally or based on simulation.
The position adjustment process of the illumination optical system 6 by the control unit 10 is the same as that in the first embodiment.

Unlike the first embodiment in which the laser beam L is emitted and the reflected laser beam L ′ is received through the same optical path, in this embodiment, the optical axis A of the illumination optical system 6 that emits the laser beam L. And the optical axis of the optical fiber 83 that receives the reflected laser beam L ′ are shifted in the XY directions. Therefore, as a result of adjusting the position of the illumination optical system 6 according to steps S1 to S5, as shown in FIG. 9, the tip 51a of the optical fiber 51 and the front focal point F of the illumination optical system 6 are shifted by Δp in the XY direction. The relative position of the scanning unit 5 and the illumination optical system 6 is adjusted to the position.
Although the illumination optical system 6 is moved in steps S1 to S5 described above, FIG. 9 shows a case where the scanning unit 5 is moved.

Δp is expressed as follows from the geometric relationship shown in FIG.
Δp + H = 2ΔpD / f (2)
From equation (2), in order for the deviation amount Δp to be equal to or less than the maximum deviation amount P allowed for position adjustment in the XY directions, the following equation (3) may be satisfied.
P ≧ Δp = fH / (2D−f)
By transforming equation (3), equation (1) is derived.

According to the present embodiment, the laser beam L emitted from the tip 51a of the optical fiber 51 follows the optical path substantially the same as the laser beam L via the reflecting surface 7a and receives light in the vicinity of the illumination optical system 6. As in the first embodiment, the efficiency of reaching the optical fiber 83 changes sensitively to changes in the relative position between the tip 51a of the optical fiber 51 and the front focal point F of the illumination optical system 6, and the optical fiber The amount of the reflected laser beam L ′ received by the light receiving optical fiber 83 changes sharply with respect to the deviation between the position of the tip 51a of 51 and the position of the front focus F of the illumination optical system 6. Therefore, based on the received light amount of the reflected laser beam L ′, the scanning unit 5 and the illumination optical system 6 are arranged so that the position of the tip 51a of the optical fiber 51 and the position of the front focal point F of the illumination optical system 6 are exactly matched. There is an advantage that the relative position can be adjusted.

Further, the light receiving unit 80 can be used to detect observation light generated in the subject by irradiation with the laser light L. That is, the common light receiving unit 80 can be used to detect the reflected laser beam L ′ and the observation light for adjusting the relative position between the scanning unit 5 and the illumination optical system 6, and the optical scanning endoscope There is an advantage that the configuration of 101 can be simplified.

In the first and second embodiments described above, the position adjustment unit 9 moves the illumination optical system 6, but instead, the position adjustment unit 9 may include only the scanning unit 5 or the scanning unit. The relative position between the tip 51a of the optical fiber 51 and the illumination optical system 6 may be adjusted by moving both the illumination optical system 5 and the illumination optical system 6.
FIG. 10 shows an example in which the position of the illumination optical system 6 is fixed and only the scanning unit 5 is moved.

In the first and second embodiments described above, the laser light L is directly incident on the illumination optical system 6 from the tip 51a of the optical fiber 51. Instead, the scanning unit 5 is shown in FIG. As shown, a lens system 53 including at least one lens may be further provided closest to the illumination optical system 6.

Thus, by providing the lens system 53 between the tip 51a of the optical fiber 51 and the illumination optical system 6, a larger space can be secured between the tip 51a of the optical fiber 51 and the illumination optical system 6. This is advantageous in assembling work of the scanning unit 5 and the like. Further, the lens system 53 can correct the aberration generated in the illumination optical system 6.

DESCRIPTION OF SYMBOLS 100,101

Optical scanning endoscope

1,20 Optical scanning apparatus 2 Insertion part 3 Case 4 Laser light source (light source)
DESCRIPTION OF SYMBOLS 5 Scan part 51 Optical fiber 52 Actuator 53 Lens system 6 Illumination optical system 7 Reflection part

7a Reflection surface

8,80

Light reception part

81,83 Optical fiber 82 Photodetector 9 Position adjustment part 91 Holding member 92 XYZ drive part 10 Control part L Laser light (illumination light)
L 'Reflected laser light

Claims

An illumination optical system for irradiating a subject with illumination light from a light source in a spot shape;
A scanning unit that scans illumination light incident on the illumination optical system from the light source in a direction intersecting an optical axis of the illumination optical system;
A reflector that is disposed opposite to the illumination optical system and reflects the illumination light emitted from the illumination optical system in parallel to the optical axis toward the illumination optical system in a direction parallel to the optical axis;
A light receiving unit that receives the illumination light reflected by the reflecting unit through an optical path of the illumination light in the illumination optical system;
A position adjusting unit that adjusts the relative position of the scanning unit and the illumination optical system in a direction parallel to and perpendicular to the optical axis of the illumination optical system;
An optical scanning device comprising: a control unit that controls the position adjustment unit based on the amount of received illumination light received by the light receiving unit.
An illumination optical system for irradiating a subject with illumination light from a light source in a spot shape;
A scanning unit that scans illumination light incident on the illumination optical system from the light source in a direction intersecting an optical axis of the illumination optical system;
A reflector that is disposed opposite to the illumination optical system and reflects the illumination light emitted from the illumination optical system in parallel to the optical axis toward the illumination optical system in a direction parallel to the optical axis;
A light receiving unit that receives the illumination light reflected by the reflecting unit in the vicinity of the illumination optical system;
A position adjusting unit that adjusts the relative position of the scanning unit and the illumination optical system in a direction parallel to and perpendicular to the optical axis of the illumination optical system;
An optical scanning device comprising: a control unit that controls the position adjustment unit based on the amount of received illumination light received by the light receiving unit.
The illumination optical system has a positive refractive power for converting the illumination light incident as a divergent light beam into a parallel light beam,
The said control part controls the said position adjustment part so that the said illumination optical system may be arrange | positioned in the position where the light-receiving amount of the said illumination light received by the said light-receiving part becomes the maximum. Optical scanning device.
The optical scanning device according to any one of claims 1 to 3, wherein the scanning unit includes a lens system closest to the illumination optical system.