JP2014166340A - Endoscope system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an endoscope system capable of suitably performing a polarization observation in desired polarization state.SOLUTION: An endoscope system includes: a light source; a polarization state setting section for allowing a light emitted from the light source to polarize in a desired polarization state; a light guiding section having an optical fiber for guiding an illumination light supplied from the polarization state setting section; a first light-receiving section for receiving a reflected light generated by the illumination light reflecting on a light emission surface of the optical fiber, and outputting a signal according to the polarization state of the reflected light received; and a control section for controlling the polarization state of the polarization state setting section on the basis of the signal outputted from the first light-receiving section.

Description

  The present invention relates to an endoscope system, and more particularly to an endoscope system capable of performing polarization observation.

  In endoscopes in the medical field, various techniques have been proposed for reducing the diameter of an insertion portion that is inserted into a body cavity of a subject in order to reduce the burden on the subject. As an example of such a technique, a scanning endoscope that does not include a solid-state imaging device in a portion corresponding to the above-described insertion portion, and a system that includes the scanning endoscope are known. ing.

  Specifically, a system having a scanning endoscope, for example, scans a subject in advance by swinging the tip of an illumination fiber that guides illumination light emitted from an illumination light supply unit. The pattern is two-dimensionally scanned, the return light from the subject is received by a light receiving fiber disposed around the illumination fiber, and an image of the subject is generated based on the return light received by the light receiving fiber. It is configured as follows. And as what has a structure similar to such a system, the scanning beam system disclosed by patent document 1 is known, for example.

  In the medical field, as a technique for obtaining histological findings on cells in a living body, for example, polarization observation using the polarization characteristics of light is conventionally performed.

  By the way, in a system configured with a scanning endoscope as described above, for example, by changing the polarization state of illumination light emitted from the illumination light supply unit to a desired polarization state, the desired While the illumination light in the polarization state can be supplied to the illumination fiber, the polarization state of the illumination light propagating through the illumination fiber provided in the insertion portion due to stress or the like caused by the insertion operation of the insertion portion This causes a problem that polarization observation in the desired polarization state cannot be suitably performed.

  On the other hand, Patent Document 1 does not particularly mention a technique that can solve the above-described problems, that is, there are still problems corresponding to the above-described problems.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide an endoscope system capable of suitably performing polarized light observation in a desired polarization state.

  An endoscope system according to an aspect of the present invention includes a light source, a polarization state setting unit capable of polarizing light emitted from the light source into a desired polarization state, and the polarization state setting unit. A light guide unit configured to include an optical fiber for guiding illumination light, and reflected light generated when the illumination light is reflected on a light exit surface of the optical fiber, and the received reflection Based on the first light receiving unit configured to output a signal corresponding to the polarization state of light and the signal output from the first light receiving unit, the polarization state of the polarization state setting unit is controlled. And a controller configured as described above.

  According to the endoscope system of the present invention, polarization observation in a desired polarization state can be suitably performed.

The figure which shows the structure of the principal part of the endoscope system which concerns on an Example. Sectional drawing for demonstrating the structure of the actuator part provided in the scanning endoscope. The figure which shows an example of the process at the time of a polarization state being aligned with the polarization direction PP which corresponds to predetermined polarization direction PH. The flowchart for demonstrating operation | movement etc. when an endoscope system is set to 1st observation mode. The figure which shows an example of the process at the time of a polarization state being aligned with the polarization direction PS orthogonal to predetermined | prescribed polarization direction PH. The flowchart for demonstrating operation | movement etc. when an endoscope system is set to 2nd observation mode.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 to 6 relate to an embodiment of the present invention. FIG. 1 is a diagram illustrating a configuration of a main part of the endoscope system according to the embodiment.

  As shown in FIG. 1, for example, the endoscope system 1 includes an illumination light supply unit 2, a single mode fiber 3, a scanning endoscope 4, an actuator unit 5, a scanning drive unit 6, and an optical fiber bundle. 7, a light detection unit 8, an image processing unit 9, a monitor 10, an optical coupler 11, a branch optical fiber 12, a reflected light receiving unit 13, a control unit 14, and an instruction input unit 15. Configured.

  The illumination light supply unit 2 includes a laser light source 2 a that emits laser light based on the control of the control unit 14, and a polarization state of the laser light emitted from the laser light source 2 a to the light incident surface of the single mode fiber 3. And a polarization state setting unit 2b for setting the polarization state according to the control.

  The laser light source 2a is configured to emit, for example, laser light in which three colors of red (R), green (G), and blue (B) are mixed based on the control of the control unit 14.

  The polarization state setting unit 2b is disposed on the optical path from the laser light source 2a to the light incident surface of the single mode fiber 3, and the optical path of the laser light emitted from the laser light source 2a is set as the rotation center. It has a half-wave plate 21 and a quarter-wave plate 22 that rotate so as to have a rotation angle according to control, respectively.

  That is, according to the configuration of the illumination light supply unit 2 as described above, the laser is obtained by combining the rotation angle of the half-wave plate 21 and the rotation angle of the quarter-wave plate 22 in the polarization state setting unit 2b. The laser light emitted from the light source 2a can be polarized in a desired polarization state, and the laser light polarized in the desired polarization state can be supplied to the single mode fiber 3 as illumination light.

  The end including the light incident surface of the single mode fiber 3 is connected to the illumination light supply unit 2. Further, the end portion including the light exit surface of the single mode fiber 3 is disposed inside the distal end portion of the scanning endoscope 4.

  The scanning endoscope 4 includes an elongated insertion portion that can be inserted into a body cavity of a subject. An optical fiber in which a single mode fiber 3 and a polarizer 7a for aligning the polarization direction of the return light from the subject to a predetermined polarization direction PH are provided on the light incident surface inside the insertion portion of the scanning endoscope 4. Each of the bundles 7 is inserted. That is, the polarizer 7a is configured to align the polarization direction of the return light incident on the light incident surface of the optical fiber bundle 7 with the predetermined polarization direction PH.

  On the other hand, the insertion portion of the scanning endoscope 4 is configured to swing the end portion including the light exit surface of the single mode fiber 3 in accordance with the drive signal supplied from the scanning drive unit 6. An actuator unit 5 is provided.

  The single mode fiber 3 and the actuator unit 5 are arranged so as to have, for example, the positional relationship shown in FIG. 2 in a cross section perpendicular to the longitudinal axis direction of the insertion portion of the scanning endoscope 4. FIG. 2 is a cross-sectional view for explaining the configuration of the actuator unit provided in the scanning endoscope.

  As shown in FIG. 2, a ferrule 41 as a joining member is disposed between the single mode fiber 3 and the actuator unit 5. Specifically, the ferrule 41 is made of, for example, zirconia (ceramic) or nickel.

  As shown in FIG. 2, the ferrule 41 is formed as a quadrangular prism, and has side surfaces 42 a and 42 c that are perpendicular to the X-axis direction (left-right direction of the paper surface) and the Y-axis direction (up-down direction of the paper surface). Vertical side surfaces 42b and 42d. A single mode fiber 3 is fixedly arranged at the center of the ferrule 41. Note that the ferrule 41 may be formed in a shape other than the quadrangular column as long as it is a rectangular column.

  As shown in FIG. 2, the actuator unit 5 includes an actuator 5a disposed along the side surface 42a, an actuator 5b disposed along the side surface 42b, an actuator 5c disposed along the side surface 42c, and a side surface 42d. And an actuator 5d disposed along the line.

  The actuators 5a and 5c are formed of, for example, a piezoelectric element, and are driven (expanded / contracted) in accordance with a drive signal supplied from the scanning drive unit 6, thereby including an end including the light emitting surface of the single mode fiber 3. The part can be swung along the X-axis direction.

  The actuators 5b and 5d are formed of, for example, a piezoelectric element, and are driven (expanded / contracted) in accordance with a drive signal supplied from the scanning drive unit 6, thereby including an end including the light emitting surface of the single mode fiber 3. The part can be swung along the Y-axis direction.

  The scanning drive unit 6 is configured to generate and output a drive signal for driving the actuator unit 5 based on the control of the control unit 14.

  The light incident surface of the optical fiber bundle 7 and the end including the polarizer 7 a are arranged inside the distal end of the scanning endoscope 4. The end including the light exit surface of the optical fiber bundle 7 is connected to the light detection unit 8.

  The light detection unit 8 is configured to generate a color signal corresponding to the intensity of the return light emitted from the optical fiber bundle 7 and output the color signal to the image processing unit 9.

  The image processing unit 9 is configured to generate an observation image corresponding to the color signal output from the light detection unit 8 and output the observation image to the monitor 10.

  The monitor 10 is configured to display an observation image or the like generated by the image processing unit 9.

  The optical coupler 11 is provided on the light guide path of the single mode fiber 3 and guides the illumination light supplied from the illumination light supply unit 2 to the light output surface side of the single mode fiber 3 while branching optical fiber. It is configured not to lead to the 12 side. The optical coupler 11 guides the Fresnel reflected light (hereinafter also simply referred to as reflected light) generated by the Fresnel reflection of the illumination light on the light exit surface of the single mode fiber 3 to the branch optical fiber 12 side, while It is configured not to lead to the light supply unit 2 side.

  That is, according to the configuration described above, the illumination light supplied from the illumination light supply unit 2 is guided by the single mode fiber 3 provided with the optical coupler 11 in the middle and irradiated to the subject. The return light of the illumination light applied to the subject is received by the optical fiber bundle 7 in which the polarizer 7a is provided on the light incident surface.

  Further, according to the configuration described above, most of the illumination light supplied from the illumination light supply unit 2 is irradiated to the subject through the light exit surface of the single mode fiber 3, while the illumination light supply unit 2 A small part of the supplied illumination light is reflected by the light exit surface of the single mode fiber 3 and guided to the branched optical fiber 12 side.

  The reflected light receiving unit 13 is disposed on the optical path of the reflected light emitted from the light emitting surface of the branch optical fiber 12, and the optical path of the reflected light emitted from the branched optical fiber 12 is the center of rotation. A half-wave plate 131 and a quarter-wave plate 132 that rotate to have a rotation angle according to control are provided. Further, the reflected light receiving unit 13 includes a polarizer 133 capable of polarizing the reflected light that has passed through the half-wave plate 131 and the quarter-wave plate 132 in a polarization direction that matches a predetermined polarization direction PH. And a photodiode 134 that receives reflected light that has passed through the polarizer 133 and outputs an electrical signal corresponding to the intensity of the received reflected light.

  That is, the reflected light receiving unit 13 of the present embodiment is configured to receive the reflected light emitted from the branch optical fiber 12 and to output a signal corresponding to the polarization state of the received reflected light.

  The control unit 14 includes a CPU and the like, and is configured to perform various controls based on a control program read from a memory (not shown).

  Specifically, based on a control program read from a memory (not shown), for example, the control unit 14 draws a locus corresponding to the irradiation position of the illumination light emitted from the scanning endoscope 4 according to a predetermined scanning pattern. In addition, the scanning drive unit 6 is configured to perform control for swinging the end including the light exit surface of the single mode fiber 3. That is, the actuator unit 5 has a function as an optical scanning unit, and based on the drive signal output from the scanning drive unit 6 according to the control of the control unit 14 as described above, The end including the light exit surface of the single mode fiber 3 can be swung so that the irradiation position draws a locus corresponding to a predetermined scanning pattern (for example, a spiral scanning pattern).

  Further, the control unit 14 is configured to be able to perform various controls based on instructions given in the instruction input unit 15.

  Specifically, the control unit 14 can perform control for switching the laser light source 2a on or off based on an instruction made in the instruction input unit 15, for example. Further, the control unit 14 is configured to set the observation mode of the endoscope system 1 to either a first observation mode or a second observation mode, which will be described later, based on an instruction given by the instruction input unit 15. It can be performed.

  Further, the control unit 14 detects the disturbance of the polarization state that occurs when light is guided by the single mode fiber 3 based on the electric signal output from the reflected light receiving unit 13, and performs polarization according to the detected disturbance of the polarization state. The state setting unit 2b is configured to control the polarization state. A specific method for detecting such polarization state disturbance will be described later.

  The instruction input unit 15 includes a user interface such as a mouse and / or a keyboard, for example, and is configured to be able to give various instructions to the control unit 14 according to a user operation.

  Specifically, the instruction input unit 15 is, for example, the first observation mode in which the observation mode of the endoscope system 1 is observed in the polarization direction PP that matches the predetermined polarization direction PH, or the predetermined polarization direction. An instruction for switching to one of the second observation modes in which observation is performed in the polarization direction PS orthogonal to PH can be given to the control unit 14.

  Subsequently, the operation of the endoscope system 1 according to the present embodiment will be described.

  First, an operation when the observation mode of the endoscope system 1 is set to the first observation mode will be described.

  The user makes an insertion part of the scanning endoscope 4 linear (state not curved in any direction) and then operates the instruction input unit 15 to instruct to turn on the laser light source 2a. And an instruction for setting the observation mode of the endoscope system 1 to the first observation mode.

  When the control unit 14 detects that the observation mode of the endoscope system 1 is set to the first observation mode based on the instruction given by the instruction input unit 15, the polarization direction according to the first observation mode is detected. Control for rotating the half-wave plate 21 and the quarter-wave plate 22 so that illumination light having a polarization direction (a polarization direction that coincides with a predetermined polarization direction PH) is supplied to the light incident surface of the single mode fiber 3. To the polarization state setting unit 2b.

  On the other hand, the control unit 14 performs control for sequentially changing the combination of the rotation angle of the half-wave plate 131 and the rotation angle of the quarter-wave plate 132 to a plurality of different combinations (1). The signal level of the electrical signal output from the photodiode 134 is monitored while the / 2 wavelength plate 131 and the 1/4 wavelength plate 132 are rotated.

  Then, the control unit 14 includes the rotation angle θHD1 of the half-wave plate 131 when the signal level of the electric signal output from the photodiode 134 has the maximum value among the plurality of different combinations described above, A combination with the rotation angle θQD1 of the quarter-wave plate 132 is detected.

  That is, when the polarization state of the reflected light emitted from the light exit surface of the branched optical fiber 12 is aligned with the polarization direction PP that matches the predetermined polarization direction PH through the process illustrated in FIG. A combination of the rotation angle θHD1 and the rotation angle θQD1 that maximizes the signal level of the electrical signal output from the diode 134 is detected. FIG. 3 is a diagram illustrating an example of a process when the polarization state is aligned with the polarization direction PP that matches the predetermined polarization direction PH.

  Here, the rotation angle θHD1 is a predetermined polarization direction PH among the polarization states of the reflected light emitted from the light exit surface of the branch optical fiber 12 when the endoscope system 1 is set to the first observation mode. Is detected as a value corresponding to the inclination angle θP of the major axis LP of the elliptically polarized light E1 when the polarization direction PP coincides with the reference direction (inclination angle = 0 °) (see FIG. 3). The rotation angle θQD1 is the ellipticity of the elliptically polarized light E1 among the polarization states of the reflected light emitted from the light exit surface of the branch optical fiber 12 when the endoscope system 1 is set to the first observation mode. It is detected as a value corresponding to the ratio of the length of the long axis LP to the length of the short axis SP in the elliptically polarized light E1 (see FIG. 3).

  That is, the rotation angle θHD1 and the rotation angle θQD1 detected in a state where the insertion portion of the scanning endoscope 4 is linearized are set when the first observation mode is initially set and light is guided by the single mode fiber 3. It can be handled as a set value for minimizing the disturbance of the polarization state.

  And the control part 14 sets correction coefficient CR preset according to the measurement result of the disorder of the polarization state in the path | route from the light emission surface of the single mode fiber 3 to the light emission surface of the branch optical fiber 12, for example. Control is performed such that the rotation angle of the half-wave plate 21 is changed so as to obtain an angle (CR × θHD1) obtained by multiplying the rotation angle θHD1. In addition, the control unit 14 performs control to change the rotation angle of the quarter-wave plate 22 so that, for example, the angle (CR × θQD1) obtained by multiplying the correction coefficient CR by the rotation angle θQD1 is obtained. . That is, by such control, in the first observation mode, illumination light polarized in advance is emitted from the illumination light supply unit 2 so as to minimize the disturbance of the polarization state that occurs when light is guided by the single mode fiber 3. Initial setting is performed.

  On the other hand, for example, the user confirms that the initial setting of the first observation mode according to the control as described above is completed based on the observation image displayed on the monitor 10, and then scans the endoscope. An insertion operation for inserting the insertion portion of the mirror 4 into the body cavity of the subject is performed. With such an insertion operation, the insertion portion of the scanning endoscope 4 is bent or curved, and the polarization state disturbance generated when the light is guided by the single mode fiber 3 is increased as compared with the time when the initial setting is completed. FIG. 4 is a flowchart for explaining an operation and the like when the endoscope system is set to the first observation mode.

  When the control unit 14 detects that the signal level of the electrical signal output from the photodiode 134 is lower than the signal level at the completion of the initial setting (step S1 in FIG. 4), the rotation angle of the half-wave plate 131 And the rotation angle of the quarter-wave plate 132 are controlled to sequentially change the combination into a plurality of different combinations, that is, the half-wave plate 131 and the quarter-wave plate 132 are rotated. Then, the signal level of the electrical signal output from the photodiode 134 is monitored (step S2 in FIG. 4).

  The control unit 14 includes the rotation angle θHDA of the half-wave plate 131 when the signal level of the electrical signal output from the photodiode 134 has the maximum value among the plurality of different combinations described above, and 1 / A combination with the rotation angle θQDA of the four-wave plate 132 is detected (step S3 in FIG. 4).

  The control unit 14 performs control for rotating the half-wave plate 21 and the quarter-wave plate 22 so that the rotation angle corresponds to the detection result of step S3 in FIG. 4 (step S4 in FIG. 4). . Specifically, the control unit 14 changes the rotation angle of the half-wave plate 21 so as to obtain an angle (CR × θHDA) obtained by multiplying the rotation coefficient θHDA by the correction coefficient CR, and the correction coefficient. Control for changing the rotation angle of the quarter-wave plate 22 so as to obtain an angle (CR × θQDA) obtained by multiplying CR by the rotation angle θQDA is performed.

  After the control according to step S4 of FIG. 4 is performed, the control unit 14 returns the rotation angles of the half-wave plate 131 and the quarter-wave plate 132 to the angles at the time of completion of the initial setting (to θHD1 and θQD1), respectively. Is controlled (step S5 in FIG. 4).

  The control unit 14 performs the control according to step S5 in FIG. 4 and then detects that the signal level of the electrical signal output from the photodiode 134 has reached the signal level at the completion of the initial setting. Then, the control after step S2 in FIG. 4 is repeated (step S6 in FIG. 4).

  According to the control of the control unit 14 as described above, in the first observation mode, polarized light whose illumination light exits from the light exit surface of the single mode fiber 3 coincides with the predetermined polarization direction PH. As a result, the polarization observation in the polarization direction PP can be suitably performed.

  Next, an operation when the observation mode of the endoscope system 1 is set to the second observation mode will be described.

  The user changes the observation mode of the endoscope system 1 to the second mode by operating the instruction input unit 15 in a state where the insertion portion of the scanning endoscope 4 is linear and the laser light source 2a is turned on. Instructs to set to observation mode.

  When the control unit 14 detects that the observation mode of the endoscope system 1 is set to the second observation mode based on the instruction given by the instruction input unit 15, the polarization direction according to the second observation mode is detected. Control for rotating the half-wave plate 21 and the quarter-wave plate 22 so that illumination light having a polarization direction (a polarization direction orthogonal to a predetermined polarization direction PH) is supplied to the light incident surface of the single mode fiber 3. To the polarization state setting unit 2b.

  On the other hand, the control unit 14 performs control for sequentially changing the combination of the rotation angle of the half-wave plate 131 and the rotation angle of the quarter-wave plate 132 to a plurality of different combinations (1). The signal level of the electrical signal output from the photodiode 134 is monitored while the / 2 wavelength plate 131 and the 1/4 wavelength plate 132 are rotated.

  Then, the control unit 14 includes the rotation angle θHD2 of the half-wave plate 131 when the signal level of the electrical signal output from the photodiode 134 among the plurality of different combinations described above has a minimum value, A combination with the rotation angle θQD2 of the quarter-wave plate 132 is detected.

  That is, when the polarization state of the reflected light emitted from the light exit surface of the branched optical fiber 12 is aligned with the polarization direction PS orthogonal to the predetermined polarization direction PH through the process illustrated in FIG. A combination of the rotation angle θHD2 and the rotation angle θQD2 that minimizes the signal level of the electrical signal output from the diode 134 is detected. FIG. 5 is a diagram illustrating an example of a process when the polarization state is aligned with the polarization direction PS orthogonal to the predetermined polarization direction PH.

  Here, the rotation angle θHD2 is a predetermined polarization direction PH among the polarization states of the reflected light emitted from the light exit surface of the branch optical fiber 12 when the endoscope system 1 is set to the second observation mode. Is detected as a value corresponding to the inclination angle θS of the major axis LS of the elliptically polarized light E2 when the polarization direction PS orthogonal to the reference direction (inclination angle = 0 °) is used (see FIG. 5). The rotation angle θQD2 is the ellipticity of the elliptically polarized light E2 among the polarization states of the reflected light emitted from the light exit surface of the branch optical fiber 12 when the endoscope system 1 is set to the second observation mode. It is detected as a value corresponding to the ratio of the length of the long axis LS to the length of the short axis SS in the elliptically polarized light E2 (see FIG. 5).

  That is, the rotation angle θHD2 and the rotation angle θQD2 detected in a state where the insertion portion of the scanning endoscope 4 is linearized are set when the light is guided by the single mode fiber 3 in the initial setting of the second observation mode. It can be handled as a set value for minimizing the disturbance of the polarization state.

  Then, for example, the control unit 14 performs control to change the rotation angle of the half-wave plate 21 so as to obtain an angle (CR × θHD2) obtained by multiplying the rotation coefficient θHD2 by the correction coefficient CR. . In addition, the control unit 14 performs control to change the rotation angle of the quarter-wave plate 22 so that, for example, the angle (CR × θQD2) obtained by multiplying the correction coefficient CR by the rotation angle θQD2 is obtained. . That is, by such control, in the second observation mode, the illumination light polarized in advance is emitted from the illumination light supply unit 2 so as to minimize the disturbance of the polarization state that occurs when light is guided by the single mode fiber 3. Initial setting is performed.

  On the other hand, for example, the user confirms that the initial setting of the second observation mode according to the control as described above is completed based on the observation image displayed on the monitor 10, and then scans the endoscope. An insertion operation for inserting the insertion portion of the mirror 4 into the body cavity of the subject is performed. With such an insertion operation, the insertion portion of the scanning endoscope 4 is bent or curved, and the polarization state disturbance generated when the light is guided by the single mode fiber 3 is increased as compared with the time when the initial setting is completed. FIG. 6 is a flowchart for explaining the operation and the like when the endoscope system is set to the second observation mode.

  When the control unit 14 detects that the signal level of the electrical signal output from the photodiode 134 has increased from the signal level at the completion of the initial setting (step S11 in FIG. 6), the rotation angle of the half-wave plate 131 And the rotation angle of the quarter-wave plate 132 are controlled to sequentially change the combination into a plurality of different combinations, that is, the half-wave plate 131 and the quarter-wave plate 132 are rotated. Then, the signal level of the electrical signal output from the photodiode 134 is monitored (step S12 in FIG. 6).

  The control unit 14 includes the rotation angle θHDB of the half-wave plate 131 when the signal level of the electrical signal output from the photodiode 134 has the minimum value among the plurality of different combinations described above, and 1 / A combination with the rotation angle θQDB of the four-wavelength plate 132 is detected (step S13 in FIG. 6).

  The control unit 14 performs control for rotating the half-wave plate 21 and the quarter-wave plate 22 so that the rotation angle corresponds to the detection result of step S13 in FIG. 6 (step S14 in FIG. 6). . Specifically, the control unit 14 changes the rotation angle of the half-wave plate 21 so as to be an angle (CR × θHDB) obtained by multiplying the correction coefficient CR by the rotation angle θHDB, and also corrects the correction coefficient. Control for changing the rotation angle of the quarter-wave plate 22 so as to obtain an angle (CR × θQDB) obtained by multiplying CR by the rotation angle θQDB is performed.

  After the control according to step S14 of FIG. 6 is performed, the control unit 14 returns the rotation angles of the half-wave plate 131 and the quarter-wave plate 132 to the angles (θHD2 and θQD2) when the initial setting is completed, respectively. Is controlled (step S15 in FIG. 6).

  The control unit 14 performs the control according to step S15 in FIG. 6 and then detects until the signal level of the electrical signal output from the photodiode 134 reaches the signal level at the completion of the initial setting. The control after step S12 in FIG. 6 and the like are repeatedly performed (step S16 in FIG. 6).

  According to the control of the control unit 14 as described above, in the second observation mode, the polarization of the illumination light emitted from the light exit surface of the single mode fiber 3 is orthogonal to the predetermined polarization direction PH. As a result, the polarization observation in the polarization direction PS can be suitably performed.

  It should be noted that the present invention is not limited to the above-described embodiments, and it is needless to say that various changes and applications can be made without departing from the spirit of the invention.

DESCRIPTION OF SYMBOLS 1 Endoscope system 2 Illumination light supply part 3 Single mode fiber 4 Scanning endoscope 5 Actuator part 6 Scan drive part 7 Optical fiber bundle 8 Optical detection part 9 Image processing part 10 Monitor 11 Optical coupler 12 Branch optical fiber 13 Reflection Light receiving unit 14 Control unit 15 Instruction input unit

US Application Publication No. 2008/0218824

Claims (13)

A light source;
A polarization state setting unit capable of polarizing the light emitted from the light source into a desired polarization state;
A light guide configured to include an optical fiber for guiding the illumination light supplied from the polarization state setting unit;
A first light-receiving unit configured to receive reflected light generated by reflection of the illumination light on a light exit surface of the optical fiber, and to output a signal corresponding to a polarization state of the received reflected light; ,
A control unit configured to control the polarization state of the polarization state setting unit based on the signal output from the first light receiving unit;
An endoscope system comprising: A second light receiving unit for receiving a return light of the illumination light irradiated to the subject through the light emitting surface;
A polarizing unit that aligns the polarization direction of the return light incident on the second light receiving unit with a predetermined polarization direction;
The endoscope system according to claim 1, further comprising: The control unit, based on the signal output from the first light receiving unit, the tilt angle of the major axis of elliptically polarized light when the predetermined polarization direction is a reference direction, the ellipticity of the elliptically polarized light, The endoscope system according to claim 2, wherein: is detected as disturbance of the polarization state. The first light receiving unit is disposed on the optical path of the reflected light, and is capable of rotating around the optical path of the reflected light as a rotation center, the first wave plate, the first wave plate, A polarizer that polarizes the reflected light that has passed through the second wave plate in a polarization direction that matches the predetermined polarization direction, and a light detection that receives the reflected light that has passed through the polarizer and outputs the signal The endoscope system according to claim 3, comprising an element. The control unit rotates the first wave plate and the second wave plate by setting the predetermined polarization direction to 0 °, so that the signal level of the signal output from the photodetecting element is a maximum value. The endoscope system according to claim 4, wherein a combination of a rotation angle of the first wave plate and a rotation angle of the second wave plate is detected. The endoscope system according to claim 5, wherein the control unit controls the polarization state setting unit based on the combination. A first observation mode in which the subject is observed in a first polarization direction that coincides with the predetermined polarization direction, or a second observation mode in which the subject is observed in a second polarization direction orthogonal to the predetermined polarization direction. The endoscope system according to claim 2, further comprising: an instruction input unit capable of instructing the control unit to switch to any one of the observation modes. The control unit uses the first polarization direction or the second polarization direction as a reference direction based on the signal output from the first light receiving unit and the instruction given by the instruction input unit. The endoscope system according to claim 7, wherein an inclination angle of a major axis of elliptically polarized light and an ellipticity of the elliptically polarized light are detected as disturbance of the polarization state. The first light receiving unit is disposed on the optical path of the reflected light, and is capable of rotating around the optical path of the reflected light as a rotation center, the first wave plate, the first wave plate, A polarizer that polarizes the reflected light that has passed through the second wave plate in a polarization direction that matches the predetermined polarization direction, and a light detection that receives the reflected light that has passed through the polarizer and outputs the signal The endoscope system according to claim 8, comprising an element. When the instruction for switching to the first observation mode is given by the instruction input unit, the control unit sets the first polarization direction to 0 ° and the first wavelength plate and the second wave By rotating each of the wave plates, the rotation angle of the first wave plate and the rotation angle of the second wave plate when the signal level of the signal output from the photodetecting element shows the maximum value. When the instruction for detecting the first combination and switching to the second observation mode is performed in the instruction input unit, the second polarization direction is set to 0 °, and the first wave plate and the By rotating the second wave plate, the rotation angle of the first wave plate and the second wave plate when the signal level of the signal output from the light detection element shows the minimum value. Second combination of rotation angles The endoscope system according to claim 9, wherein the endoscope system is detected. The control unit controls the polarization state setting unit based on the first combination when the instruction for switching to the first observation mode is performed in the instruction input unit, and the instruction input The control of the polarization state setting unit is performed based on the second combination when the instruction to switch to the second observation mode is performed in the unit. Endoscopic system. Provided on the light guide path of the fiber, and configured to guide the illumination light supplied from the illumination light supply unit to the light emitting surface side of the fiber but not to the first light receiving unit side. The optical coupler according to claim 1, further comprising an optical coupler configured to guide the reflected light to the first light receiving unit side but not to the illumination light supply unit side. Endoscope system. 2. The optical scanning unit according to claim 1, further comprising an optical scanning unit capable of swinging an end including the light emitting surface of the optical fiber so as to draw a locus corresponding to a predetermined scanning pattern. Endoscopy system.

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