WO2019022114A1 - Optical scanning observation device, optical scanning observation system and polarization direction adjustment method for optical scanning observation device - Google Patents

Abstract

An optical scanning observation device (1) is provided with: a light source unit (5) that outputs laser light; polarization adjustment units (7R, 7G, 7B) that adjust the polarization direction of the laser light outputted from the light source unit (5); an optical fiber (8) that guides the laser light the polarization direction of which is adjusted by the polarization adjustment units (7R, 7G, 7B), and emits the laser light toward an observation object; a scanning unit (9) that performs scanning with the laser light emitted from the optical fiber (8); and a light detection unit (10) that detects signal light generated in the observation object by irradiation with the laser light.

Description

Optical scanning observation apparatus, optical scanning observation system, and polarization direction adjustment method of optical scanning observation apparatus

The present invention relates to a light scanning observation apparatus, a light scanning observation system, and a polarization direction adjustment method of the light scanning observation apparatus.

2. Description of the Related Art Conventionally, there is known a laser scanning endoscope which forms an image by scanning laser light on a subject and detecting light from the subject (see, for example, Patent Document 1). The light from the subject includes surface reflected light, surface scattered light, and fluorescence. Surface reflected light is laser light specularly reflected on the surface of the subject. The surface scattered light is scattered light generated by scattering of laser light in the surface layer of the subject. The fluorescence is fluorescence generated by excitation of a self-fluorescent substance or a fluorescent dye present in a subject by laser light. In the case of an object having irregularities on the surface like a living tissue, the surface reflected light component contained in the light to be detected is reduced, but in the case of an object having a glossy surface such as a metal body, the surface reflected light component is increased. .

JP, 2011-4929, A

The incident path of light from the subject to the light receiver of the endoscope includes a first path in which light is directly incident on the light receiver from the subject, and a second path in which light from the subject is incident on the light receiver via the reflection surface. And exist. When linearly polarized light is obliquely incident on the reflecting surface, the reflectance of linearly polarized light differs depending on the incident angle and the polarization direction. Among surface scattered light from a subject, surface reflected light and fluorescence, surface reflected light is linearly polarized light having a polarization direction corresponding to the polarization direction of laser light. Therefore, the surface reflected light passing through the second path has a change in brightness depending on its polarization direction, which affects the brightness and tint of the formed image. However, in Patent Document 1, there is a problem that the polarization direction of the laser light is not considered about the influence given to the image.

For example, when three laser beams of R, G, and B are irradiated to a subject, the balance of brightness among the surface reflected lights of R, G, and B changes between the subject and the light receiver. The color of the subject inside is different from the actual color of the subject. The influence of the polarization direction of the laser light on the image is particularly observed in the observation of an object having a glossy surface such as a metal body, or in the environment where a reflector such as metal or glass is present around the object. It becomes remarkable.

Although there is a laser scanning microscope as an observation device for scanning a laser beam on a subject, in the case of a laser scanning microscope, the observation target is often a scatterer, and the laser beam is observed along a certain direction. The subject is irradiated. Therefore, the polarization direction of the laser light does not become an issue in the quality of the image. Moreover, in the case of an endoscope apparatus that irradiates the subject after the laser light is diffused by the phosphor without scanning the laser light, the polarization state of the laser light is eliminated at the diffusion stage, so the reflection angle becomes a problem. It will never be. On the other hand, in the case of a laser scanning endoscope apparatus which acquires an image based on surface reflected light like a white light image, an observation object may include a reflector, and irradiation of a laser beam to the observation object is also possible. Although the polarization direction of the laser light affects the image as the angle changes, Patent Document 1 does not consider such an influence.

The present invention has been made in view of the above-described circumstances, and an optical scanning observation apparatus, an optical scanning observation system, and an optical scanning observation apparatus capable of controlling the influence of the polarization direction of laser light on an image. It is an object of the present invention to provide a method of adjusting the polarization direction of

According to a first aspect of the present invention, there is provided a light source unit for outputting a laser beam, a polarization adjusting unit for adjusting the polarization direction of the laser beam output from the light source unit, and a polarization direction adjusted by the polarization adjusting unit. An optical fiber for guiding the laser light and emitting the laser light toward the observation target, a scanning unit for scanning the laser light emitted from the optical fiber, and the irradiation of the laser light And a light detection unit that detects the signal light to be generated.

According to a second aspect of the present invention, there is provided a light source section comprising two laser light sources, wherein the two laser light sources output two laser beams of the same color having polarization directions orthogonal to each other, and an output from the light source section A combining unit for combining the two laser beams, and an optical fiber for guiding the two laser beams combined by the combining unit and emitting the two laser beams toward an observation target An optical scanning observation comprising: a scanning unit that scans the two laser beams emitted from the optical fiber; and a light detection unit that detects signal light generated in the observation target by the irradiation of the two laser beams. It is an apparatus.

According to a third aspect of the present invention, there is provided a light source unit for outputting a laser beam, an optical fiber for guiding the laser beam output from the light source unit and emitting the laser beam toward an observation target, and the laser A depolarizing unit for depolarizing light, a scanning unit for scanning the laser beam which is depolarized by the depolarizing unit and emitted from the optical fiber, and a signal generated in the observation target by the irradiation of the laser beam It is an optical scanning observation apparatus provided with the light detection part which detects light.

According to a fourth aspect of the present invention, there is provided an optical scanning observation apparatus according to the first aspect, and an apparatus for adjusting the polarization direction used for adjusting the polarization direction of the laser beam emitted from the optical scanning observation apparatus. And a polarization selecting unit for selecting a polarization component in a predetermined direction among the laser beams emitted from the light scanning observation apparatus, and the polarization selecting unit selecting the polarization direction adjusting device. And a light amount detection unit configured to detect the light amount of the polarization component in the predetermined direction.

A fifth aspect of the present invention is a polarization direction adjustment method for adjusting the polarization direction of laser light emitted from a light scanning observation apparatus, which emits laser light, and the polarization direction of the emitted laser light is It is a polarization direction adjustment method which detects and adjusts the polarization direction of the laser beam emitted from the light scanning observation apparatus in a predetermined direction.

According to the present invention, it is possible to control the influence of the polarization direction of laser light on an image.

BRIEF DESCRIPTION OF THE DRAWINGS It is a whole block diagram of the light scanning observation apparatus which concerns on the 1st Embodiment of this invention, and a light scanning observation system. It is a flowchart explaining the polarization direction adjustment method by the light scanning observation system of FIG. It is a graph explaining the relationship between the polarization direction of a laser beam, and a reflectance. It is a whole block diagram of the light scanning observation apparatus which concerns on the 2nd Embodiment of this invention. It is a whole block diagram of the light scanning observation apparatus which concerns on the 3rd Embodiment of this invention. It is a whole block diagram of the light scanning observation apparatus which concerns on the 4th Embodiment of this invention. It is a whole block diagram of the light scanning observation apparatus which concerns on the 5th Embodiment of this invention. It is a whole block diagram of the modification of the light scanning observation apparatus of FIG.

First Embodiment
A light scanning observation apparatus 1 according to a first embodiment of the present invention and a light scanning observation system 100 including the light scanning observation apparatus 1 will be described with reference to FIGS. 1 to 3.
As shown in FIG. 1, the light scanning observation system 100 according to the present embodiment two-dimensionally scans laser light on an object (observation object) and generates an image based on signal light from the object. A scanning observation apparatus 1 and a polarization direction adjustment device 30 used to adjust the polarization direction of laser light emitted from the light scanning observation apparatus 1 are provided.

The light scanning observation apparatus 1 is an endoscope apparatus including a long scope 2 inserted into a body and a control device main body 3 connected to a proximal end of the scope 2. A display 4 for displaying an image generated in the control device main body 3 is connected to the control device main body 3.

In addition, the light scanning observation apparatus 1 includes a light source unit 5 that outputs a plurality of laser beams having different colors, a coupler 6 that coaxially combines a plurality of laser beams output from the light source unit 5, and a laser beam. An illumination fiber (optical fiber) for guiding the laser beam whose polarization direction has been adjusted by the polarization adjustment units 7R, 7G, 7B for adjusting the polarization direction of the light and the polarization adjustment units 7R, 7G, 7B 8, a scanning unit 9 for scanning a laser beam emitted from the illumination fiber 8, a light detection unit 10 for detecting a signal beam generated on the subject by the irradiation of the laser beam, an intensity of the signal beam and an irradiation position of the laser beam And a controller 12 for controlling the entire optical scanning observation apparatus 1.

The light source unit 5 is provided in the control device main body 3. The light source unit 5 controls three laser light sources 13R, 13G and 13B for emitting red (R), green (G) and blue (B) laser beams, and a light emission control unit for controlling the laser light sources 13R, 13G and 13B. And fourteen.
The laser light sources 13R, 13G, and 13B are, for example, a DPSS laser (semiconductor-pumped solid-state laser) or a laser diode, and respectively emit laser light which is linearly polarized light.
The light emission control unit 14 causes the laser light sources 13R, 13G, and 13B to emit light in a pulse shape in accordance with the control signal from the control unit 12.

The polarization adjustment units 7R, 7G, 7B are disposed on the optical path between the laser light sources 13R, 13G, 13B and the coupler 6. The polarization adjustment units 7R, 7G, and 7B change the polarization direction of the laser light according to the control signal from the control unit 12. The polarization adjusting units 7R, 7G, 7B are, for example, a paddle type or in-line type polarization controller. The paddle type or in-line type polarization controller polarization direction of the laser light guided in the optical fiber 17 by applying stress from the outside to the optical fiber 17 connecting the laser light sources 13R, 13G, 13B and the coupler 6 Change. Alternatively, the polarization adjusting units 7R, 7G, 7B may be spatial type polarization controllers using one or more polarizing elements such as a polarizer, a half wave plate, or a quarter wave plate. .

The illumination fiber 8 is a single mode optical fiber. The illumination fiber 8 is disposed along the longitudinal direction in the scope 2, and the proximal end of the illumination fiber 8 is connected to the coupler 6. The illumination fiber 8 guides the laser light supplied from the coupler 6 and emits it from the tip toward the object facing the tip surface of the scope 2.

The scanning unit 9 includes an actuator 15 provided in the illumination fiber 8, and an actuator driver 16 provided in the control device main body 3 and driving the actuator 15 in accordance with a drive signal from the control unit 12.
The actuator 15 is, for example, a piezoelectric actuator including a piezoelectric element, and is attached to the illumination fiber 8 at a position distant from the tip of the illumination fiber 8 to the proximal side. The actuator 15 vibrates the tip of the illumination fiber 8 in a direction intersecting the longitudinal direction of the illumination fiber 8 by applying an alternating voltage from the actuator driver 16. Thereby, the laser beam emitted from the tip of the illumination fiber 8 is scanned in the direction crossing the optical axis of the laser beam. The actuator 15 may be an electromagnetic actuator including a cylindrical permanent magnet having magnetic poles at both ends and fixed to the side surface of the illumination fiber 8 and an electromagnet for applying a magnetic field to the magnetic poles of the permanent magnet.

The light detection unit 10 detects signal light via the light receiving fiber 18 disposed in the scope 2 along the longitudinal direction, and transmits information of the detected signal light intensity to the image generation unit 11. Such a light detection unit 10, for example, a photodetector that outputs an electric signal corresponding to the intensity of the signal light by photoelectrically converting the signal light, and an AD that digitally converts the electric signal output from the light detector. And a converter.

The light receiving fiber 18 is a multimode optical fiber. The signal light returned from the subject to the tip of the scope 2 is received by the light receiving fiber 18 and guided to the light detection unit 10 by the light receiving fiber 18. In order to increase the light reception amount of the signal light, the light detection unit 10 may be configured to receive the signal light from the plurality of light receiving fibers 18 aligned in the circumferential direction of the scope 2.

The image generation unit 11 generates an image by associating the intensity value of the signal light received from the light detection unit 10 with the irradiation position (described later) of the laser light received from the control unit 12. The generated image is transmitted from the image generation unit 11 to the display 4 and displayed on the display 4. The image generation unit 11 may transmit the image to the display 4 after performing arbitrary image processing (for example, scan conversion, interpolation processing, enhancement processing, γ processing, and the like) on the image.

The control unit 12 transmits a control signal to the light emission control unit 14. The light emission control unit 14 controls the light emission timing of the laser light sources 13R, 13G, and 13B according to the control signal. Further, the control unit 12 transmits a drive signal to the actuator driver 16. The actuator driver 16 controls the vibration of the tip of the illumination fiber 8 by the actuator 15, that is, the scanning of the laser light, according to the drive signal. The control unit 12 calculates the irradiation position of the laser beam from the drive signal, and transmits information of the calculated irradiation position to the image generation unit 11.

The image generation unit 11 and the control unit 12 are, for example, a processor such as a CPU (central processing unit) and a storage device for storing a program for causing the processor to execute the processing of the image generation unit 11 and the control unit 12 described above. And may be realized by a computer comprising

The polarization direction adjustment device 30 is a separate device from the scope 2 and the control device body 3. The polarization direction adjusting device 30 is connected to the control device body 3 by wire or wireless in use, and is disposed to face the tip of the scope 2. The polarization direction adjusting device 30 includes a polarization plate 31 (polarization selection portion) on which the laser light emitted from the tip of the scope 2 is incident, and a light amount detection portion 32 for detecting the light amount of the laser light transmitted through the polarization plate 31. Have.

The polarizing plate 31 has a single polarization axis, and selectively transmits only the polarization component in the direction parallel to the polarization axis.
For example, similarly to the light detection unit 10, the light amount detection unit 32 includes a light detector and an AD converter. Information on the light amount detected by the light amount detection unit 32 is transmitted to the control unit 12 in the control device main body 3 by wire or wirelessly.

Next, the polarization direction adjustment operation (polarization direction adjustment method) by the control unit 12 using the polarization direction adjustment device 30 will be described with reference to FIG. The polarization direction adjustment operation is performed, for example, before shipment of the light scanning observation apparatus 1 or before observation by the light scanning observation apparatus 1.
First, the polarization direction adjusting device 30 is disposed so that the polarizing plate 31 faces the tip of the scope 2, and then the polarization direction adjusting operation by the control unit 12 shown in FIG. 2 is started.

The control unit 12 causes only the R laser light source 13R to start emitting light (step S1). The R laser light output from the laser light source 13R passes through the polarization adjusting unit 7R, the coupler 6, and the illumination fiber 8, is emitted from the tip of the scope 2 toward the polarizing plate 31, and passes through the polarizing plate 31. The light amount is detected by the light amount detection unit 32. The detected light amount of the R laser light detected by the light amount detection unit 32 is transmitted from the light amount detection unit 32 to the control unit 12.

Here, the transmitted light amount of the laser beam transmitted through the polarizing plate 31 and the detected light amount by the light amount detection unit 32 change in accordance with the polarization direction of the laser light. That is, when the polarization direction of the laser light is parallel to the polarization axis of the polarizing plate 31, the transmitted light amount and the detected light amount become maximum, and when the polarization direction of the laser light is orthogonal to the polarization axis of the polarizing plate 31, the transmitted light amount and detection The light amount is minimized. Therefore, the control unit 12 can detect the polarization direction of the R laser light with respect to the polarization axis of the polarizing plate 31 based on the detected light amount from the light amount detection unit 32.

The control unit 12 causes the polarization adjustment unit 7R to change the polarization direction of the laser light until the detected light amount of the laser light detected by the light amount detection unit 32 becomes maximum. The control unit 12 detects the polarization direction of the R laser light when the detected light amount becomes maximum, that is, when it becomes parallel to the polarization axis of the polarizing plate 31 (step S2). Next, the control unit 12 fixes the polarization adjusting unit 7R in the polarization direction at which the detected light amount is maximum (step S3), and turns off the R laser light source 13R (step S4). Thus, the polarization direction of the R laser light is adjusted to be parallel to the polarization axis of the polarizing plate 31.

Next, the control unit 12 causes only the G laser light source 13G to start emitting light (step S5), and similarly to steps S2, S3 and S4, the polarization direction of the G laser light when the detected light quantity is maximum Is detected (step S6), the polarization adjusting unit 7G is fixed in the polarization direction when the detected light quantity is maximum (step S7), and the G laser light source 13G is turned off (step S8). Thereby, the polarization direction of the G laser light is adjusted to be parallel to the polarization axis of the polarizing plate 31.

Next, the control unit 12 causes only the laser light source 13B of B to start light emission (step S9), and in the same manner as steps S2, S3 and S4, the polarization direction of the laser light of B when the detected light quantity becomes maximum. Is detected (step S10), the polarization adjusting unit 7B is fixed in the polarization direction when the detected light quantity is maximum (step S11), and the laser light source 13B of B is turned off (step S12). Thereby, the polarization direction of the B laser light is adjusted to be parallel to the polarization axis of the polarizing plate 31.

By adjusting the above steps S1 to S12, the polarization directions of the R, G, and B laser beams emitted from the tip of the scope 2 become mutually the same.
After completion of the polarization direction adjusting operation, the polarization direction adjusting device 30 is removed from the scope 2 and the control device body 3. Thereafter, image acquisition by the light scanning observation apparatus 1 is started.

Next, the operation of the light scanning observation apparatus 1 will be described.
The control unit 12 starts transmitting a drive signal for vibrating the tip of the illumination fiber 8 to the actuator driver 16. In addition, the control unit 12 starts transmitting a control signal for causing the R, G, and B laser light sources 13R, 13G, and 13B to emit light in order to the light emission control unit 14. As a result, the R, G, and B laser beams are sequentially emitted while being scanned from the tip of the vibrating illumination fiber 8, and the R, G, and B laser beams are sequentially applied to the subject. Therefore, in the subject, R, G, and B signal lights are generated in order.

The R, G, and B signal lights are received by the light receiving fiber 18 at the tip end surface of the scope 2 and guided to the light detection unit 10. Then, in the light detection unit 10, the intensity value of the signal light which is the value of each pixel of the image is obtained. The intensity value is associated with the irradiation position of the laser light in the image generation unit 11, whereby a color image of the subject is generated. The generated image is displayed on the display 4.

In this case, signal light from the subject includes surface reflected light, surface scattered light, and fluorescence. The surface reflected light is light specularly reflected on the surface of the object, and is linearly polarized light having a polarization direction according to the polarization direction of the laser light. Surface scattered light is light scattered in the surface layer of an object, and is randomly polarized light including polarized light in various directions. The fluorescence is light generated by a self-fluorescent substance or a fluorescent dye excited by laser light, and is randomly polarized light.

For example, in an environment where reflecting surfaces exist around the tip of the scope 2 and the subject, such as when the scope 2 is disposed in a metal tube, surface reflected light from the subject is received by the light receiving fiber 18, It is possible to undergo reflection by the reflecting surface. The reflectance of surface reflected light by the reflective surface differs depending on the polarization direction. FIG. 3 shows the relationship between the polarization direction of linearly polarized light and the reflectance. As shown in FIG. 3, the reflectance when obliquely incident on the reflecting surface is different between p-polarized light and s-polarized light. This is because, for example, when red p-polarized light and green s-polarized light simultaneously enter the reflection surface at an incident angle of 70 °, the reflected light from the reflection surface becomes green, that is, light before and after reflection by the reflection surface Means that the color of

Therefore, if the polarization directions of the R, G, and B laser beams are different from each other, the intensities of the R, G, and B signal lights detected by the light detection unit 10 under the influence of the reflection on the reflection surface. As a result, the tint of the generated image is different from the actual tint of the subject.

According to this embodiment, the polarization directions of the R, G, and B laser beams emitted to the subject from the tip of the scope 2 are the same. Therefore, even if the surface reflected light generated in the subject passes through the reflection on the reflecting surface, the surface reflected lights of R, G and B are reflected at the same reflectance each other, so the signal light of R, G and B is There is no change in the balance of strength between them. Therefore, the tint generated from the intensity values of the R, G, and B signal lights is the same as the tint of the subject. As described above, by adjusting the polarization direction of the laser light by the polarization adjustment units 7R, 7G, and 7B, it is possible to control the influence of the polarization direction of the laser light on the image. For example, even in an environment where a reflector such as metal or glass is present around the scope 2 or in a subject, the influence of the polarization direction of the R, G, and B laser light on the tint of the image can be controlled. There is an advantage that the color tone of the subject can be accurately reproduced in the image.

In the present embodiment, in steps S2, S6 and S10, the polarization direction of the laser light is controlled to the polarization direction at which the detected light amount detected by the light amount detection unit 32 is maximum. Alternatively, control may be performed in the polarization direction when the amount of light detected by the light amount detection unit 32 is minimized. In this case, the polarization directions of the R, G, and B laser beams are adjusted in the direction orthogonal to the polarization axis of the polarizing plate 31.

In the present embodiment, the control unit 12 automatically adjusts the polarization directions of the R, G, and B laser beams by controlling the polarization adjustment units 7R, 7G, and 7B, but instead, the user can The polarization direction may be manually adjusted by performing steps S1 to S12 while manually operating the polarization adjusting units 7R, 7G, and 7B.

In the present embodiment, the polarization directions of all the R, G and B laser beams are made to coincide with each other, but instead, the polarization directions of the R, G and B laser beams are different from each other It may be adjusted to By doing this, the intensities of the R, G, and B signal lights detected by the light detection unit 10 differ from each other according to the incident angle of the laser light on the surface of the subject. Therefore, in observation of a subject having a concavo-convex structure, it is possible to acquire an image in which the structure of the subject is emphasized by the difference in color.
For example, as shown in FIG. 3, the difference in reflectance between p-polarized light and s-polarized light is large when the incident angle is in the range of 45 ° to 90 °. Therefore, by adjusting the tilt angle of the scope 2 with respect to the subject, structures within the range of 45 ° to 90 ° can be confirmed in the image.

In the present embodiment, the three polarization adjusting units 7R, 7G, and 7B are provided corresponding to all the laser light sources 13R, 13G, and 13B, but instead, any one polarization adjusting unit 7R, 7G or 7B may be omitted. By doing this, the number of parts can be reduced.
In this case, the polarization directions of the two laser beams in which the corresponding polarization adjusting units exist are adjusted in the same direction as the polarization directions of the laser beams in which the corresponding polarization adjusting units do not exist. For example, in the case where the polarization adjusting unit 7R corresponding to the R laser light source 13R is omitted, the polarization plate 31 with respect to the polarization direction of the R laser light in the direction in which the detection light amount of the R laser light by the light amount detection unit 32 is maximum. The polarization axis of is adjusted and fixed. Next, the polarization adjustment units 7G and 7B adjust the polarization directions of the G and B laser beams in the polarization direction in which the amount of light detected by the light amount detection unit 32 is maximum.

In the present embodiment, the laser light sources 13R, 13G, and 13B respectively output continuous laser beams of R, G, and B, and the coupler 6 combines the laser beams of R, G, and B to generate white laser beams. It may be configured to supply the illumination fiber 8. In this case, a color separation element (not shown) for separating the signal light received by the light receiving fiber 18 into R, G and B wavelength components, and R, G and B wavelength components separated by the color separation element And three light detection units 10 that respectively detect.

Second Embodiment
Next, an optical scanning observation apparatus according to a second embodiment of the present invention will be described with reference to FIG.
In the present embodiment, a configuration different from the first embodiment will be described, and the configuration common to the first embodiment is assigned the same reference numeral and the description will be omitted.
The light scanning observation apparatus 101 according to the present embodiment is an endoscope apparatus provided with a scope 2 and a control device main body 3 as shown in FIG. The light scanning observation apparatus 101 includes a laser whose light is depolarized by the light source unit 5, the coupler 6, depolarization units 20R, 20G, and 20B for depolarization of laser light, and depolarization units 20R, 20G, and 20B. An illumination fiber 8 for guiding light to emit light toward a subject A, a scanning unit 9, a light detection unit 10, an image generation unit 11, and a control unit 12 are provided.

The depolarization units 20R, 20G, and 20B are disposed on the optical path between the laser light sources 13R, 13G, and 13B and the coupler 6. The depolarization units 20R, 20G, and 20B convert the laser beams incident from the corresponding laser light sources 13R, 13G, and 13B into randomly polarized light and output the light. As the depolarizers 20R, 20G, and 20B, for example, depolarizers made of quartz and which disturb the polarization state of the laser beam are used. The laser light depolarized by the depolarization units 20R, 20G, and 20B passes through the coupler 6 and the illumination fiber 8, and is emitted from the tip of the scope 2 toward the subject A.

As described above, according to the present embodiment, the R, G, and B laser beams emitted from the tip of the scope 2 are randomly polarized light. Therefore, the reduction rates of the light quantity of the surface reflected light of R, G and B when reflected by the reflecting surface are equal to each other, and there is no change in the balance of the intensities among the R, G and B signal lights. . Therefore, the tint generated from the detection values of the R, G, and B signal lights is the same as the actual tint of the subject A. Thereby, for example, even in an environment where a reflector such as metal or glass is present around the scope 2 or the subject A, the influence of the polarization direction of the R, G, and B laser light on the tint of the image is controlled. And the color of the subject can be accurately reproduced in the image.

In the present embodiment, the depolarization units 20R, 20G, and 20B are provided one by one in the optical path between the laser light sources 13R, 13G, and 13B and the coupler 6, but instead of this, A single depolarization unit may be provided on the optical path of the laser light from the coupler 6 to the tip of the scope 2.
By doing this, the polarization of the R, G and B laser beams output from the coupler 6 can be canceled by the common depolarization unit.

Third Embodiment
Next, an optical scanning observation apparatus according to a third embodiment of the present invention will be described with reference to FIG.
In the present embodiment, a configuration different from the first embodiment will be described, and the configuration common to the first embodiment is assigned the same reference numeral and the description will be omitted.
The light scanning observation apparatus 102 according to the present embodiment is an endoscope apparatus provided with a scope 2 and a control device main body 3 as shown in FIG. The light scanning observation device 102 is added to the light source unit 5, the coupler 6, the polarization adjusting units 7 R, 7 G, 7 B, the illumination fiber 8, the scanning unit 9, the light detecting unit 10, the image generating unit 11, and the control unit 12. , And a rotary polarizing plate (polarization switching unit) 21.

The polarization directions of the R, G, and B laser beams entering the coupler 6 are adjusted in the same direction by the polarization direction adjusting operation using the polarization direction adjusting device 30 described in the first embodiment. It is adjusted by the parts 7R, 7G, 7B. The polarization direction of the R, G, B laser beams adjusted by the polarization adjusting units 7R, 7G, 7B is defined as 45 °.

The rotary polarizing plate 21 is connected to the coupler 6 via the optical fiber 19, and the laser light output from the coupler 6 is incident along the incident optical axis. The rotary polarizing plate 21 is provided rotatably around the incident light axis, and the rotation angle is controlled by the control unit 12. Similar to the polarizing plate 31, the rotating polarizing plate 21 has a single polarization axis, and selectively transmits only the polarization component in the direction parallel to the polarization axis. Therefore, as the rotation angle of the rotary polarizing plate 21 about the incident optical axis changes, the polarization direction of the laser light transmitted through the rotary polarizing plate 21 changes. The control unit 12 switches the rotation angle of the rotation polarization plate 21 between 0 ° and 90 ° to make the polarization direction of the laser light emitted from the rotation polarization plate 21 0 ° (first direction) and 90 °. Switch between ° (second direction).
The arrangement of the rotary polarizing plate 21 shown in FIG. 5 is an example, and the rotary polarizing plate 21 can be arranged at any position on the optical path of the laser light between the coupler 6 and the tip of the scope 2.

Next, the operation of the light scanning observation apparatus 102 will be described.
The control unit 12 sets the rotational polarization plate 21 to 0 °, and operates the light source unit 5, the scanning unit 9, and the light detection unit 10 to generate an image (first image) when the polarization direction is 0 °. The image generation unit 11 generates the image. The generated image is recorded in a memory (not shown). Next, the control unit 12 sets the rotational polarization plate 21 to 90 °, and operates the light source unit 5, the scanning unit 9, and the light detection unit 10 to obtain an image (second second) when the polarization direction is 90 °. The image generation unit 11 generates an image). The generated image is recorded in the memory.

Next, the image generation unit 11 reads an image when the polarization direction is 0 ° and an image when the polarization direction is 90 ° from the memory, and combines these two images to generate a composite image. For example, the image generation unit 11 calculates the average value of the values of two pixels at the same position, generates a composite image with the calculated average value as the value of the pixel at that position, and transmits the composite image to the display 4 Do. Even if the image generation unit 11 transmits or displays the image when the polarization direction is 0 ° and the image when the polarization direction is 90 ° to the display 4 instead of or in addition to the composite image. Good.

As described above, the reflectance of the linearly polarized light at the reflective surface changes depending on the incident angle to the reflective surface. By using the R, G, B laser beams having the same polarization direction, it is possible to prevent the change in the color of the signal light due to the reflection on the reflection surface, but the difference in the incident angle to the reflection surface It is not possible to prevent the brightness variation in the image caused by
According to the present embodiment, two images are generated when the observation target B is irradiated with laser beams whose polarization directions are different from each other. Based on these two images, it is possible to grasp the influence of the polarization direction, in particular, the variation in brightness depending on the polarization direction. Then, by averaging two images acquired using laser beams whose polarization directions are mutually orthogonal, a composite image in which the color tone of the subject is accurately reproduced and in which the variation in brightness is reduced There is an advantage that you can get

In the present embodiment, instead of averaging the two images of 0 ° and 90 °, the image generation unit 11 selects the larger value of the values of the two pixels at the same position. A composite image may be generated.
Also in this case, it is possible to generate a composite image in which the variation in brightness depending on the polarization direction of the laser light is reduced.

In the present embodiment, the rotary polarizing plate 21 is used as a means for switching the polarization direction of the laser light. However, instead of this, a half-wave plate (polarization switching unit) may be used.
In this case, the direction of the laser beam can be rotated by 90 ° by inserting and removing a half wavelength on the optical path of the R, G, and B laser beams.
The rotation of the polarization direction of the laser beam by the rotary polarizer 21 involves the attenuation of the laser beam, but the half-wave plate can rotate the polarization direction without attenuating the laser beam.

In the present embodiment, switching of the polarization direction of the laser light by the rotary polarizing plate 21 is performed in units of one frame, but instead of this, switching may be performed in scan units of scanning trajectories, pixel units, or pulses. Good.

The optical fiber used on the output side of the scope 2 from the laser light sources 13R, 13G, and 13B may be a polarization maintaining fiber whose polarization direction is maintained. The use of a polarization maintaining fiber has the advantage that the polarization state does not change regardless of the routing of the optical fiber.
In addition, a polarization filter may be disposed at the tip of the scope 2 and the polarization state of the laser light of each color may be aligned with the direction of the polarization filter. By disposing the polarizing filter at the tip of the scope 2, it is possible to align the polarization direction of the laser light emitted from the tip of the scope 2 with the polarization direction of the signal light received at the tip of the scope 2. In addition, even if the polarization states of the R, G, and B laser beams are somewhat different depending on the routing of the optical fiber, there is an advantage that the polarization direction can be surely aligned at the output end of the scope 2.

Fourth Embodiment
Next, an optical scanning observation apparatus according to a fourth embodiment of the present invention will be described with reference to FIG.
In the present embodiment, configurations different from the first to third embodiments will be described, and configurations common to the first to third embodiments will be assigned the same reference numerals and descriptions thereof will be omitted.
The light scanning observation apparatus 103 according to the present embodiment is an endoscope apparatus provided with a scope 2 and a control device main body 3 as shown in FIG. In addition to the light source unit 5, the coupler 6, the polarization adjustment units 7R, 7G and 7B, the illumination fiber 8, the scanning unit 9, the light detection unit 10, the image generation unit 11, and the control unit 12, the light scanning observation device 103 , And a quarter wave plate (λ / 4 plate) 22.

The polarization directions of the R, G, and B laser beams entering the coupler 6 are adjusted in the same direction by the polarization direction adjustment operation using the polarization direction adjusting device described in the first embodiment. It is adjusted by 7R, 7G, 7B.
The illumination fiber 8 is preferably a polarization maintaining fiber. The polarization maintaining fiber has the property of maintaining the polarization state of the incident linearly polarized light. When a polarization maintaining fiber is used as the illumination fiber 8, the R, G, and B laser beams entering the λ / 4 plate 22 from the illumination fiber 8 are linearly polarized light having the same polarization direction.

In the case of a normal optical fiber which is not a polarization maintaining fiber, the polarization state of linearly polarized light incident on the optical fiber gradually changes during the light guiding of the optical fiber due to the bending of the optical fiber and the like. Therefore, when a normal optical fiber is used as the illumination fiber 8, it is preferable that the illumination fiber 8 be fixed from the coupler 6 to the vicinity of the tip of the scope 2 so that the stress state does not change from the time of polarization direction adjustment. By this, as in the case of using the polarization maintaining fiber, it is possible to make the R, G and B laser beams entering the λ / 4 plate 22 from the illumination fiber 8 into linearly polarized light having the same polarization direction. it can.

The λ / 4 plate 22 is disposed between the tip of the illumination fiber 8 and the subject A. For example, the λ / 4 plate 22 is disposed on the distal end surface of the scope 2. The optical axis of the λ / 4 plate 22 is inclined 45 ° with respect to the polarization direction of the R, G, B laser beams emitted from the tip of the illumination fiber 8. The R, G, and B laser beams incident on the λ / 4 plate 22 are converted to clockwise or counterclockwise circularly polarized light by the λ / 4 plate 22, and R, G, B of circularly polarized light from the λ / 4 plate 22. Laser light is emitted.

Thus, according to the present embodiment, the R, G, and B laser beams emitted from the tip of the scope 2 are each circularly polarized. Therefore, the surface reflectances of the R, G, and B laser beams when reflected by the reflection surface are equal to each other, and there is no change in the balance of intensities among the R, G, and B signal beams. Furthermore, since the frequency of circularly polarized light is sufficiently large compared to the frame rate of the light scanning observation apparatus 103, the surface reflectance of circularly polarized laser light is equivalent to the reflective surface in any direction, There is no change in the intensity balance of the R, G and B signal lights for each reflecting surface. Therefore, there is an advantage that it is possible to obtain an image in which the color tone of the subject is accurately reproduced and in which the variation in brightness due to the difference in the direction of the reflecting surface is prevented.

The specific example of the adjustment method of the polarization direction of the laser beam in this embodiment is shown below.
In an example of the adjustment method, the polarization directions of the R, G, and B laser beams are adjusted in the same direction by the polarization method adjustment operation described in the first embodiment. Next, the optical axis of the λ / 4 plate 22 is inclined 45 degrees with respect to the polarization direction of the R, G, and B laser beams, and the direction of the λ / 4 plate 22 is fixed.

In another example of the adjustment method, a polarization direction adjustment device 30 further provided with a λ / 4 plate (not shown) having an optical axis inclined 45 degrees with respect to the polarization axis of the polarization plate 31 is used. The λ / 4 plate is disposed between the tip of the scope 2 and the polarizing plate 31. In the present adjustment method, when the laser light emitted from the scope 2 is circularly polarized light, the light amount detected by the light amount detection unit 32 is maximized, so the procedure is the same as the operation described in the first embodiment. The polarization direction of the laser light can be adjusted. The polarization direction of the laser light may be adjusted such that the angle of the polarizing plate 31 is further inclined by 90 ° and the amount of light detected becomes minimum.

In the present embodiment, the laser beam which is linearly polarized light is converted to circularly polarized light by the λ / 4 plate 22. Alternatively, the laser beam may be converted to elliptically polarized light by the wavelength plate. For example, the laser beam may be converted into elliptically polarized light by the λ / 4 plate 22.

In the first, third and fourth embodiments, the polarization adjusting units 7R, 7G and 7B are provided, but instead, the polarization of the laser light is adjusted by adjusting the positions of the laser light sources 13R, 13G and 13B. You may control the direction.
For example, the polarization direction of the laser light emitted from the tip of the scope 2 may be controlled in a desired direction by adjusting the rotation angles of the laser light sources 13R, 13G, 13B around the output optical axis of the laser light. Such positional adjustment of the laser light sources 13R, 13G, 13B is performed, for example, at the time of assembly of the apparatus.

Fifth Embodiment
Next, an optical scanning observation apparatus according to a fifth embodiment of the present invention will be described with reference to FIGS. 7 and 8. FIG.
In the present embodiment, configurations different from the first to fourth embodiments will be described, and configurations common to the first to fourth embodiments will be assigned the same reference numerals and descriptions thereof will be omitted.
The light scanning observation device 104 according to the present embodiment is an endoscope device provided with a scope 2 and a control device main body 3 as shown in FIG. The light scanning observation device 104 includes a light source unit 51, a coupler 6, polarization adjustment units 7R, 7G, 7B, an illumination fiber 8, a scanning unit 9, a light detection unit 10, an image generation unit 11, a control unit 12, and multiplexing. The units 23R, 23G, and 23B are provided.

The light source unit 51 includes separators 24R, 24G, and 24B in addition to the laser light sources 13R, 13G, and 13B and the light emission control unit 14.
The splitters 24R, 24G, and 24B are disposed between the laser light sources 13R, 13G, and 13B and the coupler 6, respectively, and separate the R, G, and B laser beams into two laser beams. Preferably, each of the separators 24R, 24G, 24B separates the laser light into two laser lights of equal light amount. Each of the splitters 24R, 24G, and 24B is, for example, an optical fiber coupler that connects one optical fiber connected to each of the laser light sources 13R, 13G, and 13B and two optical fibers connected to the coupler 6. It is. The splitters 24R, 24G, 24B may be composed of one or more optical elements such as beam splitters or half mirrors.

The polarization adjusting units 7R, 7G, 7B are respectively disposed on the optical paths of the two laser beams separated by the separators 24R, 24G, 24B. Therefore, in the present embodiment, six polarization adjusting units 7R, 7G, 7B are provided. The two polarization adjusting units 7R adjust the polarization directions of the two R laser beams separated by the separator 24R in directions orthogonal to each other. The two polarization adjusting units 7G adjust the polarization directions of the two G laser beams separated by the separator 24G in directions orthogonal to each other. The two polarization adjusting units 7B adjust the polarization directions of the two B laser beams separated by the separator 24B in directions orthogonal to each other. Here, “orthogonal” means that the complex inner product of the Jones vectors of each of the two laser light polarization states is zero.

The couplers 23R, 23G, and 23B are disposed between the polarization adjusters 7R, 7G, and 7B and the coupler 6, respectively. The combining unit 23R combines the two R laser beams whose polarization directions are adjusted by the two polarization adjusting units 7R. The coupler 23G couples the two G laser beams whose polarization directions are adjusted by the two polarization adjusters 7G. The combining unit 23B combines the two B laser beams whose polarization directions are adjusted by the two polarization adjusting units 7B.

The R, G, and B laser beams multiplexed by the couplers 23R, 23G, and 23B enter the illumination fiber 8 via the coupler 6. Therefore, each of the R, G, and B laser beams emitted from the tip of the illumination fiber 8 is light in a state in which the amounts of light are equal to each other, and two polarized lights whose polarization directions are orthogonal to each other are combined. is there. It is preferable that the illumination fiber 8 be fixed to the scope 2 and the control device body 3 in order to prevent the polarization state of each laser beam from changing while guiding light in the illumination fiber 8.

As described above, according to the present embodiment, each of the R, G, and B laser beams emitted from the scope 2 is a combined light of two polarized lights whose light amounts are equal and whose polarization directions are orthogonal to each other. Therefore, the surface reflectances of the R, G, and B laser beams when reflected by the reflection surface are equal to each other, and there is no change in the balance of intensities among the R, G, and B signal beams. Furthermore, since two polarizations orthogonal to each other are multiplexed, reflected light with a constant intensity is received regardless of the orientation of the reflection surface. Therefore, there is an advantage that it is possible to obtain an image in which the color tone of the subject is accurately reproduced and in which the variation in brightness due to the difference in the direction of the reflecting surface is prevented.

Further, according to the present embodiment, the routing of the illumination fiber 8 is changed because each of the R, G, and B laser beams output from the coupler 6 is a combined light of two polarized lights orthogonal to each other. Also, the intensity balance between the R, G, and B signal lights due to reflection and the intensity balance of the signal light for each direction of the reflection surface do not change.
This is because the orthogonal state of the two polarizations does not break even if the routing of the illumination fiber 8 changes. The change of the polarization state due to the routing of the illumination fiber 8 is due to the birefringence caused by the stress applied to the illumination fiber 8 and the optical rotation due to the twist. The Jones matrix T of an optical fiber to which indeterminate stress and twist are applied is expressed by the following equation.

The above T is unitary because it satisfies T ^* T = TT ^* = I. This means that the complex inner product of the Jones vectors of the two polarizations incident on the illumination fiber 8 is preserved even if the routing changes. When the two polarizations are orthogonal as in this embodiment, the complex inner product of the Jones vectors of the two polarizations is zero, and the orthogonality is maintained even if the routing changes.

In the present embodiment, the polarization direction of the laser light is adjusted using the polarization direction adjusting device 30.
Specifically, in order to adjust the polarization direction of the R laser beam, the polarization adjusting unit 7R of the other R laser beam is operated in a state in which one R laser beam is blocked, and the other R laser The polarization direction of the light is adjusted in the direction in which the amount of light detected by the polarization adjustment device 30 is minimum or maximum. The blocking of the laser light is performed, for example, by removing the connector of the optical fiber that guides the laser light. Next, the polarizing plate 31 of the polarization direction adjusting device 30 is rotated by 90 °. Next, the polarization adjusting unit 7R of one R laser beam is operated in a state of blocking the other adjusted R laser beam, and the polarization direction of the one R laser beam is detected by the polarization adjusting device 30. Adjust in the direction of minimum or maximum light intensity. Thereby, the polarization directions of the two R laser beams are adjusted in directions orthogonal to each other.
The polarization directions of the two laser beams G and B are also adjusted in the same procedure as the laser beam R.

At this time, the polarization directions of the R, G, and B laser beams may be the same or may not be the same. In addition, when the polarization directions of the two laser beams separated by the respective separators 24R, 24G, and 24B are clear, the polarization directions of the two laser beams can be adjusted by adjusting only the polarization direction of one of the two laser beams. May be orthogonal to each other.

Two polarizations that are orthogonal to each other ideally do not interfere with each other in the optical fiber. However, if the core of the optical fiber is not ideally circular, or birefringence occurs due to the stress applied at the time of drawing the optical fiber, a coherent component may occur to the two polarizations. If interference occurs between two separated laser beams, the intensities of the two laser beams after multiplexing are different from the simple sum of the intensities of the two laser beams generated by the separators 24R, 24G or 24B. Sometimes. If such a phenomenon is a problem, the two separated laser beams may be made incoherent by making the optical path length of one of the two separated laser beams longer than the coherent length of the laser beam. .

In the present embodiment, in order to output two laser beams of the same color, the light source unit 51 is provided with the separating units 24R, 24G, and 24B, but instead, as shown in FIG. Two laser light sources 13R, 13G, and 13B of respective colors may be provided. In the light scanning observation apparatus 105 of FIG. 8, the polarization directions of the two laser beams of each color are adjusted by the polarization adjustment units 7R, 7G, and 7B.

The light scanning observation apparatus 105 may not include the polarization adjusting units 7R, 7G, and 7B, and may output laser light having polarization directions orthogonal to each other from two laser light sources 13R, 13G, and 13B of the same color.
In the polarization direction adjustment method of such an optical scanning observation apparatus, the polarization direction of the laser light is adjusted by the rotation angle around the output optical axis of the laser light sources 13R, 13G, 13B. That is, by rotating at least one of the two laser light sources 13R about the output optical axis, the polarization directions of the two R laser beams output from the two laser light sources 13R are adjusted in directions orthogonal to each other. , Fix the two laser light sources 13R. Similarly, the polarization directions of the two G laser beams are adjusted in directions orthogonal to each other, and the two laser light sources 13G are fixed. Further, the polarization directions of the two B laser beams are adjusted in directions orthogonal to each other, and the two laser light sources 13B are fixed. Adjustment of the polarization direction is performed, for example, at the time of assembly of the device.

100 light scanning type observation system 1, 101, 102, 103, 104, 105 light scanning type observation device 2 scope 3 control device main body 4 display 5, 51 light source unit 6 coupler 7R, 7G, 7B polarization adjustment unit 8 illumination fiber 9 Scanning unit 10 Photodetection unit 11 Image generation unit 12 Control unit 13R, 13G, 13B Laser light source 14 Light emission control unit 15 Actuator 16 Actuator driver 17 Optical fiber 18 Light reception fiber 20R, 20G, 20B Depolarization unit 21 Rotational polarization plate (polarization switching Department)
22 Quarter Wave Plate (Wave Plate)
23R, 23G, 23B Combiner 24R, 24G, 24B Separator 30 Device for adjusting polarization direction 31 Polarizer (polarization selector)
32 Light quantity detector

Claims (14)

1. A light source unit that outputs laser light;
   A polarization adjustment unit that adjusts the polarization direction of the laser beam output from the light source unit;
   An optical fiber for guiding the laser light whose polarization direction has been adjusted by the polarization adjustment unit and emitting the laser light toward an observation target;
   A scanning unit for scanning the laser beam emitted from the optical fiber;
   And a light detection unit configured to detect signal light generated in the observation target by the irradiation of the laser light.
2. A polarization switching unit provided between the polarization adjusting unit and the scanning unit and switching the polarization direction of the laser light between a first direction and a second direction;
   An image generation unit configured to generate an image of the observation target based on the signal light detected by the light detection unit;
   The image generation unit generates a first image when the polarization direction of the laser light is the first direction, and a second image when the polarization direction of the laser light is the second direction The optical scanning observation apparatus according to claim 1, which generates
3. The optical scanning observation apparatus according to claim 2, wherein the image generation unit combines the first image and the second image to generate a combined image.
4. The optical scanning observation apparatus according to any one of claims 1 to 3, wherein the optical fiber is a polarization maintaining fiber.
5. A wavelength plate is provided between the optical fiber and the observation target, and the wavelength plate converts the laser beam incident from the optical fiber into laser light of circular polarization or elliptical polarization. The light scanning observation apparatus according to any one of the above.
6. The light source unit outputs two laser beams of the same color,
   The polarization adjusting unit adjusts polarization directions of the two laser beams of the same color in directions orthogonal to each other,
   The optical scanning observation apparatus according to any one of claims 1 to 4, further comprising: a combining unit configured to combine the two laser beams of the same color adjusted by the polarization adjusting unit.
7. The light source unit includes three laser light sources that respectively output red, green and blue laser light,
   The optical scanning observation apparatus according to any one of claims 1 to 6, wherein the polarization adjusting unit adjusts the polarization direction of at least one of the red, green and blue laser beams.
8. The light source unit outputs a plurality of the laser beams,
   The optical scanning observation apparatus according to any one of claims 1 to 7, wherein the polarization adjusting unit adjusts at least two polarization directions of the plurality of laser beams in the same direction.
9. A light source unit comprising two laser light sources, wherein the two laser light sources output two laser lights of the same color having polarization directions orthogonal to each other;
   A combining unit that combines the two laser beams output from the light source unit;
   An optical fiber for guiding the two laser beams combined by the combining unit and emitting the two laser beams toward an observation target;
   A scanning unit that scans the two laser beams emitted from the optical fiber;
   And a light detection unit configured to detect signal light generated in the observation target by the irradiation of the two laser lights.
10. A light source unit that outputs laser light;
    An optical fiber for guiding the laser light output from the light source unit and emitting the laser light toward an observation target;
    A depolarizer configured to depolarize the laser light;
    A scanning unit that scans the laser beam emitted from the optical fiber by depolarization by the depolarization unit;
    And a light detection unit configured to detect signal light generated in the observation target by the irradiation of the laser light.
11. An optical scanning observation apparatus according to any one of claims 1 to 8.
    A polarization direction adjusting device used to adjust the polarization direction of the laser beam emitted from the light scanning observation device;
    The device for adjusting the polarization direction is
    A polarization selection unit for selecting a polarization component in a predetermined direction among the laser beams emitted from the light scanning observation device;
    And a light amount detection unit for detecting a light amount of the polarization component in the predetermined direction selected by the polarization selection unit.
12. A control unit that controls the polarization adjusting unit;
    12. The light scanning according to claim 11, wherein the control unit adjusts the polarization direction of the laser beam to a direction in which the light amount detected by the light amount detection unit becomes maximum or minimum by controlling the polarization adjusting unit. Type observation system.
13. The optical scanning observation system according to claim 11 or 12, wherein the polarization selection unit is disposed between the polarization adjustment unit and the light amount detection unit.
14. A polarization direction adjusting method for adjusting the polarization direction of laser light emitted from a light scanning observation apparatus, comprising:
    Emit a laser beam,
    Detecting the polarization direction of the emitted laser beam;
    The polarization direction adjusting method for adjusting the polarization direction of the laser beam emitted from the light scanning observation apparatus to a predetermined direction.

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