WO2013089053A1 - Scanning endoscope system - Google Patents

Scanning endoscope system Download PDF

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Publication number
WO2013089053A1
WO2013089053A1 PCT/JP2012/081894 JP2012081894W WO2013089053A1 WO 2013089053 A1 WO2013089053 A1 WO 2013089053A1 JP 2012081894 W JP2012081894 W JP 2012081894W WO 2013089053 A1 WO2013089053 A1 WO 2013089053A1
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WO
WIPO (PCT)
Prior art keywords
light
scanning
optical fiber
endoscope system
image signal
Prior art date
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PCT/JP2012/081894
Other languages
French (fr)
Japanese (ja)
Inventor
貴雄 牧野
洋一 人形
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Hoya株式会社
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Publication date
Priority to JP2011-271374 priority Critical
Priority to JP2011271374 priority
Application filed by Hoya株式会社 filed Critical Hoya株式会社
Publication of WO2013089053A1 publication Critical patent/WO2013089053A1/en

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    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B23/00Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies; Viewfinders; Optical aiming or sighting devices
    • G02B23/24Instruments or systems for viewing the inside of hollow bodies, e.g. fibrescopes
    • G02B23/2407Optical details
    • G02B23/2423Optical details of the distal end
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • A61B1/00163Optical arrangements
    • A61B1/00172Optical arrangements with means for scanning
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • A61B1/04Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor combined with photographic or television appliances
    • A61B1/043Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor combined with photographic or television appliances for fluorescence imaging
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • A61B1/04Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor combined with photographic or television appliances
    • A61B1/045Control therefor
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • A61B1/04Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor combined with photographic or television appliances
    • A61B1/05Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor combined with photographic or television appliances characterised by the image sensor, e.g. camera, being in the distal end portion
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • A61B1/06Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor with illuminating arrangements
    • A61B1/07Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor with illuminating arrangements using light-conductive means, e.g. optical fibres
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B23/00Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies; Viewfinders; Optical aiming or sighting devices
    • G02B23/24Instruments or systems for viewing the inside of hollow bodies, e.g. fibrescopes
    • G02B23/26Instruments or systems for viewing the inside of hollow bodies, e.g. fibrescopes using light guides
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B26/00Optical devices or arrangements using movable or deformable optical elements for controlling the intensity, colour, phase, polarisation or direction of light, e.g. switching, gating, modulating
    • G02B26/08Optical devices or arrangements using movable or deformable optical elements for controlling the intensity, colour, phase, polarisation or direction of light, e.g. switching, gating, modulating for controlling the direction of light
    • G02B26/10Scanning systems
    • G02B26/103Scanning systems having movable or deformable optical fibres, light guides or waveguides as scanning elements

Abstract

This scanning endoscope system is provided with: a first optical fiber that guides illuminating light supplied by a predetermined light source to an emission end, and emits said light on a target; an optical fiber scanning means that drives the emission end of the optical fiber in a spiral pattern in such a manner that the illuminating light rotationally scans in a spiral pattern from the center to the periphery of an approximately circular scanning region; a light source control means that controls the emission of the illuminating light; an image signal detection means that receives backscattered light returned by the target, and detects an image signal; and an image generation means that uses the detected image signal to generate an image of the target. The light source control means causes the illuminating light to be emitted in pulses when the illuminating light scans the center of the scanning region, and causes the illuminating light to be emitted continuously when the illuminating light scans the periphery of the scanning region.

Description

Scanning endoscope system

The present invention relates to a scanning endoscope system in which a subject is rotationally scanned in a spiral shape with predetermined scanning light, and return light returned from the scanned subject is detected and imaged.

2. Description of the Related Art Conventionally, a scanning confocal endoscope system is known as one of scanning endoscope systems in which light guided by an optical fiber is scanned with respect to an observation site and the reflected light is received and imaged. It has been. A specific configuration of this type of scanning confocal endoscope system is disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-321792. Hereinafter, Japanese Patent Application Laid-Open No. 2004-321792 is referred to as “Patent Document 1”. A scanning confocal endoscope system irradiates a living tissue to which a drug is administered with a laser beam, and among the fluorescence emitted from the living tissue, a pin arranged at a position conjugate to the focal position of the confocal optical system By extracting only the components through the holes, the living tissue can be observed at a higher magnification than an observation image obtained by a normal endoscope optical system. A scanning confocal endoscope system scans a living tissue two-dimensionally or three-dimensionally with a laser beam that cannot be observed at a magnification of an observation image obtained by a normal endoscope optical system. It is configured such that a simple object can be observed and a tomographic part of a living tissue can be observed.

In recent years, a scanning endoscope system that scans light guided by an optical fiber in a spiral shape with respect to an observation site and receives the reflected light to form an image is disclosed, for example, in US Pat. No. 6,856. No. 6,712, US Pat. No. 6,959,130, and US Pat. No. 6,975,898. Hereinafter, US Pat. No. 6,856,712 is referred to as “Patent Document 2”, US Pat. No. 6,959,130 is referred to as “Patent Document 3”, and US Pat. No. 6,975,898. The specification is referred to as “Patent Document 4”. In such a scanning endoscope system, a single mode type optical fiber is provided in the endoscope. Inside the endoscope, the proximal end portion of the optical fiber is held in a cantilever shape by a piezoelectric actuator. Then, the piezoelectric actuator modulates and amplifies the vibration amplitude, two-dimensionally vibrates (resonates) the fiber tip according to the natural frequency, and drives the tip of the optical fiber in a spiral shape. As a result, the illumination light guided from the light source by the optical fiber is irradiated in a spiral toward the observation site, and an image of the irradiation region (scanning region) is acquired.

In recent years, a scanning endoscope system configured to scan light in a spiral shape as described in Patent Documents 2 to 4 is used as a scanning confocal endoscope as described in Patent Document 1. For example, Japanese Patent Application Laid-Open No. 2010-162090 proposes application to a mirror system. Hereinafter, Japanese Patent Application Laid-Open No. 2010-162090 will be referred to as “Patent Document 5”.

The scanning endoscope systems described in Patent Documents 2 to 5 will be described in detail. The system bends an optical fiber in a predetermined direction by applying a voltage having a predetermined period and amplitude to each piezoelectric actuator, and optically The continuous light guided by the fiber is swirled with respect to the observation site. The system receives the reflected light from the scanning region (observation site) at a predetermined cycle timing (hereinafter referred to as “sampling point”) to form an image, and displays a two-dimensional endoscopic image.

FIG. 9 is a schematic diagram showing the relationship between the scanning trajectory of light and the sampling points in the conventional scanning endoscope system. As shown in FIG. 9, the conventional scanning endoscope system employs a configuration in which continuous light is scanned in a spiral shape from the central portion to the peripheral portion of the scanning region. Here, since the scanning speed of the light is different between the central portion and the peripheral portion of the scanning region, it can be seen that sampling points are concentrated in the central portion of the scanning region. That is, the amount of light (irradiation energy) per unit area of the scanning region (observation site) differs greatly between the central portion and the peripheral portion of the scanning region. Therefore, not only does the brightness of the endoscopic image have a large drop between the central part and the peripheral part, but also, for example, as a result of increasing the laser intensity to ensure the brightness of the peripheral part of the scanning region, scanning There is a possibility that the laser beam more than necessary may be irradiated to the affected part located in the central part of the region.

Further, when the scanning endoscope system having such a configuration is applied to a scanning confocal endoscope system using fluorescence from a living tissue as described in Patent Document 1, irradiation per unit area is performed. Decomposition of the phosphor proceeds faster at the center of the scanning area where energy is high. As a result, the central portion of the scanning region becomes darker (fading) than the peripheral portion, and there arises a problem that an endoscopic image with uniform brightness cannot be obtained.

The present invention has been made in view of the above circumstances, and an object of the present invention is to perform scanning capable of suppressing variations in irradiation energy per unit area in a scanning region in order to suppress the above-described problem. A type endoscope system is provided.

A scanning endoscope system according to an aspect of the present invention guides irradiation light supplied from a predetermined light source to an emission end, and emits the first optical fiber to the subject from the emission end, Irradiation light emitted from the exit end of the optical fiber spirals at a constant rotation period from the center to the periphery within a substantially circular scanning region centered on the axis extending in the longitudinal direction of the first optical fiber. An optical fiber scanning unit that rotationally drives the exit end of the first optical fiber in a spiral manner so as to perform rotational scanning, a light source control unit that controls on / off of irradiation light, and a subject that is irradiated with irradiation light are returned from the subject. Receiving the return light, and detecting an image signal at a predetermined detection timing, and an image generation means for generating a confocal image using the detected image signal, and the light source control means Center of light in the scanning area When scanning, the irradiation light is emitted in a pulse shape with a driving pulse having a predetermined pulse width, and the irradiation light is continuously emitted when the irradiation light scans the peripheral portion in the scanning region. To do.

With such a configuration, the irradiation energy of the irradiation light is reduced at the central portion in the scanning area where the irradiation energy has been high conventionally, so that, for example, the progress of fading in the central portion of the scanning area can be suppressed, The problem that the laser beam more than necessary is irradiated to the affected part located in the central part can be avoided. Further, variation in irradiation energy per unit area in the scanning region is suppressed, and an image with substantially uniform brightness can be obtained from the central portion to the peripheral portion of the scanning region.

Further, the image generation means may be configured to allocate a two-dimensional pixel position according to the detection timing of the image signal, and generate the image by arranging the image signal at the allocated pixel position. Further, the light source control means, when the detection timings of a plurality of consecutive image signals are assigned to the same two-dimensional pixel position, any one of the detection timings of the plurality of consecutive image signals as a reference timing, A configuration may be adopted in which drive pulses are generated based on the reference timing. According to such a configuration, it is possible to easily generate a drive pulse synchronized with the detection timing of the image signal.

Also, the light source control means is preferably configured to generate a drive pulse prior to the reference timing.

Further, it is preferable that the light source control means generates the drive pulse so as to include the reference timing. According to such a configuration, it is possible to reliably detect, for example, the fluorescence emitted from the subject by the pulsed excitation light and the reflected light of the pulsed light irradiated on the subject at the reference timing.

The light source control means includes first input means for receiving an input from the user, and adjusts a time between the generation timing of the drive pulse and the reference timing in accordance with the user input received by the first input means. Can be configured to. According to such a configuration, since it becomes possible to arbitrarily adjust the timing at which the irradiation light starts to be irradiated, for example, a change in the signal delay time or the fluorescence reagent reaction time due to a change in the system configuration or the fluorescence reagent. Even if it occurs, it is possible to reliably detect the fluorescence emitted from the subject by the pulsed excitation light and the reflected light of the pulsed light irradiated to the subject at the reference timing.

Further, it is preferable that the detection timing of the image signal is a constant cycle, and the pulse width of the drive pulse is longer than the cycle of the detection timing of the image signal. According to such a configuration, it is possible to sufficiently irradiate the subject, and thus it is possible to obtain a sufficient amount of fluorescence and reflected light. Further, it is possible to reliably detect fluorescence and reflected light even when the delay time caused by the system varies.

Further, the light source control means may include a second input means that receives an input from the user, and may be configured to adjust the pulse width of the drive pulse according to the user input received by the second input means. According to such a configuration, since the pulse width of the drive pulse can be adjusted according to the reaction time of the fluorescent reagent, the reaction time of the fluorescent reagent varies depending on the type of fluorescent reagent and the subject. However, it is possible to sufficiently excite the subject and obtain a sufficient amount of fluorescence. Further, it is possible to reliably detect fluorescence and reflected light even when the delay time caused by the system varies.

Further, it is preferable that the diameter of the central portion in the scanning area is approximately 1/3 or less of the diameter of the scanning area.

Further, the optical fiber scanning means may be configured to stop the rotational driving of the emission end of the first optical fiber for a predetermined period after rotationally driving the emission end of the first optical fiber in a spiral shape. In this case, the light source control means is preferably configured to stop the emission of the irradiation light for a predetermined period. According to such a configuration, the progress of fading due to unnecessary excitation light can be suppressed, and unnecessary laser light irradiation to the affected area can be suppressed.

The irradiation light is, for example, excitation light. The image signal detection means receives the fluorescence generated from the subject excited by the excitation light through a confocal pinhole disposed at a position conjugate with the condensing point of the excitation light, and receives the image signal at a predetermined detection timing. It is good also as a structure which detects. The confocal pinhole is, for example, the exit end of the first optical fiber disposed at a position conjugate with the condensing point of the excitation light.

The irradiation light may be light including a wavelength in the visible region. The image signal detection means may be configured to receive reflected light from a subject irradiated with light including a wavelength in the visible region and detect the image signal at a predetermined detection timing. An example of light including wavelengths in the visible region is light including wavelengths of R (Red), G (Green), and B (Blue). In this case, the image signal detection means is configured to separate and receive light of R, G, and B wavelengths from the reflected light from the subject and detect the image signal at a predetermined detection timing.

The image signal detection means is a second optical fiber that receives the reflected light from the subject, and reflected light that is incident on the second optical fiber, and is used for light of each wavelength of R, G, and B. Wavelength selection means corresponding to each wavelength of R, G, and B arranged at different positions in the light guide path of the second optical fiber so that different optical path differences are given, and different optical path differences depending on the wavelength selection means Is provided with light receiving means for receiving light of each wavelength of R, G, B with a predetermined time difference, and at a predetermined detection timing from light of each wavelength of R, G, B received with a predetermined time difference The image signal may be detected.

According to one aspect of the present invention, it is possible to suppress the progress of fading in the central portion of the scanning region while suppressing variations in irradiation energy per unit area in the scanning region, and to the affected portion in the central portion of the scanning region. There is provided a scanning endoscope system capable of suppressing irradiation of laser light more than necessary.

It is a block diagram which shows the structure of the scanning confocal endoscope system of embodiment of this invention. It is a figure which shows schematically the structure of the confocal optical unit which the scanning confocal endoscope system of embodiment of this invention has. It is a figure which shows the rotation locus | trajectory of the front-end | tip of an optical fiber on an XY approximate surface. It is a figure regarding the intensity | strength of the excitation light which the light source of embodiment of this invention inject | emits. It is a figure which shows the relationship between the position (sampling point) of excitation light, and the pixel position (raster coordinate) of an endoscopic image. It is a figure explaining the relationship between the remap table of the center part of a scanning area | region, and light emission pattern data, and the relationship between a sampling point and a raster coordinate. It is a figure which shows typically the relationship between the excitation light irradiated in a pulse form based on light emission pattern data, and a raster coordinate. It is a timing chart which shows the relationship between each sampling point and a laser drive signal. It is a schematic diagram which shows the relationship between the scanning locus | trajectory of light and a sampling point in the conventional scanning endoscope system. It is a schematic diagram which shows the structure of the scanning endoscope system of another embodiment. It is a block diagram which shows the structure of the system main body which the scanning endoscope system of another embodiment has. It is a sectional side view which shows the internal structure of the front-end | tip part of the scanning endoscope which the scanning endoscope system of another embodiment has. It is a perspective view which shows the internal structure of the front-end | tip part of the scanning endoscope of another embodiment.

Hereinafter, a scanning endoscope system according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a scanning confocal endoscope system 1 according to an embodiment of the present invention. The scanning confocal endoscope system 1 according to the present embodiment is a system designed by applying the principle of a confocal microscope, and is preferably configured to observe a subject with high magnification and high resolution. As shown in FIG. 1, the scanning confocal endoscope system 1 includes a system main body 100, a confocal probe 200, a monitor 300, and a calibration unit 400. Confocal observation using the scanning confocal endoscope system 1 is performed in a state where the distal end surface of a flexible tubular confocal probe 200 is applied to a subject.

The system main body 100 includes a light source 102, an optical demultiplexer / multiplexer (photocoupler) 104, a damper 106, a CPU 108, a CPU memory 110, an optical fiber 112, a light receiver 114, a video signal processing circuit 116, an image memory 118, and a remap table. A memory 119, a video signal output circuit 120, a laser control circuit 122, an operation panel 124, and an A / D 130. The confocal probe 200 includes an optical fiber 202, a confocal optical unit 204, a sub CPU 206, a sub memory 208, and a scanning driver 210.

The light source 102 emits excitation light (for example, laser light having a wavelength of 488 nm) that excites the fluorescent substance contained in the medicine administered into the body cavity of the patient according to the drive control of the laser control circuit 122 according to the instruction of the CPU 108. . The excitation light enters the optical demultiplexer / multiplexer 104. An optical connector 152 is coupled to one of the ports of the optical demultiplexer / multiplexer 104. The unnecessary port of the optical demultiplexer-multiplexer 104 is coupled to a damper 106 that terminates the excitation light emitted from the light source 102 without reflection. The excitation light incident on the former port passes through the optical connector 152 and enters the optical system arranged in the confocal probe 200.

The proximal end of the optical fiber 202 is coupled to the optical demultiplexer / multiplexer 104 through the optical connector 152. The distal end portion of the optical fiber 202 is housed in a confocal optical unit 204 incorporated in the distal end portion of the confocal probe 200. The excitation light emitted from the optical demultiplexer-multiplexer 104 passes through the optical connector 152 and is incident on the base end of the optical fiber 202 (end on the system main body 100 side), and then transmitted through the optical fiber 202 to be transmitted to the optical fiber 202. Are emitted from the tip (end portion on the tip side of the confocal probe 200).

FIG. 2A is a diagram schematically showing the internal configuration of the confocal optical unit 204. Hereinafter, for convenience of describing the confocal optical unit 204, the longitudinal direction of the confocal optical unit 204 is defined as the Z direction, and two directions orthogonal to the Z direction and orthogonal to each other are defined as the X direction and the Y direction. As shown in FIG. 2A, the confocal optical unit 204 has a metal outer cylinder 204A that houses various components. The outer cylinder 204A holds an inner cylinder 204B having an outer wall surface shape corresponding to the inner wall surface shape of the outer cylinder 204A so as to be slidable coaxially (Z direction). The distal end 202a of the optical fiber 202 is supported by a holding member (not shown) in a state of being accommodated in the inner cylinder 204B through openings formed in the base end surfaces of the outer cylinder 204A and the inner cylinder 204B. The tip 202a functions as a secondary point light source of the scanning confocal endoscope system 1. The position of the tip 202a, which is a point light source, periodically changes based on control by the CPU. In FIG. 2A, the central axis AX indicates the central axis of the confocal optical unit 204. When the optical fiber 202 is in the initial position (when the optical fiber 202 is not vibrated), the center axis AX and the axis of the optical fiber 202 coincide.

The sub memory 208 stores probe information such as identification information and various properties of the confocal probe 200. The sub CPU 206 reads probe information from the sub memory 208 when the system is activated, and transmits the probe information to the CPU 108 via the electrical connector 154 that electrically connects the confocal probe 200 to the system main body 100. The CPU 108 stores the transmitted probe information in the CPU memory 110. The CPU 108 reads the stored probe information when necessary, generates a signal necessary for controlling the confocal probe 200, and transmits the signal to the sub CPU 206. The sub CPU 206 designates a setting value necessary for the scan driver 210 in accordance with the control signal transmitted from the CPU 108.

A biaxial actuator 204C is bonded and fixed to the outer peripheral surface of the optical fiber 202 near the tip 202a. FIG. 2B is a diagram schematically showing the configuration of the biaxial actuator 204C. As shown in FIG. 2B, the biaxial actuator 204C includes a pair of X-axis electrodes (“X” and “X ′” in the figure) and Y-axis electrodes (in the figure) connected to the scanning driver 210. “Y”, “Y ′”) are piezoelectric actuators formed on a piezoelectric body.

The scan driver 210 generates a drive signal based on the set value designated by the sub CPU 206, and drives and controls the biaxial actuator 204C by the generated drive signal. More specifically, the scanning driver 210 applies the AC voltage X between the X-axis electrodes of the biaxial actuator 204C to resonate the piezoelectric body in the X direction, and has the same frequency as the AC voltage X and the phase is orthogonal. An alternating voltage Y is applied between the Y-axis electrodes to resonate the piezoelectric body in the Y direction. The AC voltages X and Y are respectively defined as voltages that increase linearly in proportion to time and reach effective values (X) and (Y) over time (X) and (Y). The tip 202a of the optical fiber 202 is on a surface that approximates the XY plane (hereinafter referred to as "XY approximate surface") by combining the kinetic energy in the X and Y directions by the biaxial actuator 204C. In FIG. 5, the coil moves so as to draw a spiral pattern around the central axis AX. The rotation trajectory of the tip 202a increases in proportion to the applied voltage, and draws a circular trajectory having the largest diameter when the AC voltage having the effective values (X) and (Y) is applied. FIG. 3 shows the rotation locus of the tip 202a on the XY approximate plane.

The excitation light emitted from the light source 102 is transmitted through the optical fiber 202 according to the laser drive signal supplied from the laser control circuit 122 to the light source 102 during the period from the start of application of AC voltage to the biaxial actuator 204C to the stop of application. The light is emitted from the tip 202a in a predetermined light emission pattern. Hereinafter, for convenience of explanation, this period is referred to as a “sampling period”. The excitation light emitted from the tip 202a scans a predetermined circular scanning region centered on the central axis AX in a spiral shape by moving the tip 202a spirally on the XY approximate plane during the sampling period. When the application of the AC voltage to the biaxial actuator 204C is stopped after the sampling period has elapsed, the vibration of the optical fiber 202 is attenuated. The movement of the tip 202a on the XY approximate plane converges as the vibration of the optical fiber 202 is attenuated, and becomes substantially zero after a predetermined time (that is, the tip 202a almost stops on the central axis AX). Hereinafter, for convenience of explanation, a period from the end of the sampling period until the tip 202a substantially stops on the central axis AX is referred to as a “braking period”. After the braking period, the next sampling period is started after waiting for a predetermined time. Hereinafter, for convenience of description, a period from the end of the braking period to the start of the next sampling period is referred to as a “settling period”. The settling period is a waiting time for completely stopping the tip 202a on the central axis AX. By setting the settling time, the rotation trajectory of the tip 202a can be stabilized. By stabilizing the rotation trajectory of the tip 202a, it becomes possible to guarantee the scanning accuracy for the subject. The period corresponding to one frame is composed of one sampling period and one braking period, and a settling period can be selectively added. The frame rate can be flexibly changed by adjusting the settling period. Thus, the settling period can be set as appropriate from the relationship between the time until the tip 202a completely stops and the frame rate. In order to shorten the braking period, a braking torque may be positively applied by applying a reverse phase voltage to the biaxial actuator 204C in the initial stage of the braking period.

An objective optical system 204D is installed in front of the tip 202a of the optical fiber 202 (FIG. 2). The objective optical system 204D is composed of a plurality of optical lenses, and is held by the outer cylinder 204A via a lens frame (not shown). The optical axis of the objective optical system 204D coincides with the central axis AX. The lens frame is supported inside the outer cylinder 204A while being fixed relative to the inner cylinder 204B. Therefore, the objective optical system 204D held by the lens frame slides in the Z direction integrally with the inner cylinder 204B inside the outer cylinder 204A. The distal end surface of the outer cylinder 204A is sealed with a cover glass (not shown).

A compression coil spring 204E and a shape memory alloy 204F are attached between the base end surface of the inner cylinder 204B and the inner wall surface of the outer cylinder 204A. The compression coil spring 204E is initially compressed and clamped in the Z direction from the natural length. The shape memory alloy 204F has a long bar shape in the Z direction, deforms when an external force is applied at room temperature, and has a property of restoring to a predetermined shape by a shape memory effect when heated to a certain temperature or higher. ing. The shape memory alloy 204F is designed such that the restoring force due to the shape memory effect is larger than the restoring force of the compression coil spring 204E. The scan driver 210 generates a drive signal corresponding to the set value designated by the sub CPU 206, and controls the amount of expansion / contraction of the shape memory alloy 132F by energizing and heating the shape memory alloy 204F with the generated drive signal. The shape memory alloy 204F advances and retracts the inner tube 204B in the Z direction together with the optical fiber 202 according to the amount of expansion and contraction. Specifically, the shape memory alloy 204F is heated and extends (restores) in the Z direction, thereby pushing the inner tube 204B forward (Z direction) together with the optical fiber 202. The shape memory alloy 204F is also compressed in the Z direction by the compression coil spring 204E as the restoring force due to the shape memory effect decreases as the slow cooling progresses, and the inner tube 204B is moved backward along the optical fiber 202 (Z direction). Withdraw.

The excitation light emitted from the tip 202a of the optical fiber 202 passes through the objective optical system 204D and forms a spot on the surface or surface layer of the subject. The spot formation position is displaced in the Z-axis direction in accordance with the advance / retreat of the tip 202a that is a point light source. That is, the confocal optical unit 204 scans the subject three-dimensionally by combining the periodic circular motion of the tip 202a on the XY approximate plane by the biaxial actuator 204C and the advance and retreat in the Z direction.

Since the tip 202a of the optical fiber 202 is disposed at the front focal position of the objective optical system 204D, it functions as a confocal pinhole. Of the fluorescence emitted from the subject excited by the excitation light, only the fluorescence from the condensing point optically conjugate with the tip 202a is incident on the tip 202a. The fluorescence that has entered the optical fiber 202 from the tip 202 a is transmitted through the optical fiber 202, passes through the optical connector 152, and enters the optical demultiplexer / multiplexer 104. The optical demultiplexer / multiplexer 104 separates the incident fluorescence from the excitation light emitted from the light source 102 and guides it to the optical fiber 112. The fluorescence is transmitted through the optical fiber 112 and detected by the light receiver 114. Since the light receiver 114 detects weak light with low noise, a high-sensitivity photodetector such as a photomultiplier tube can be employed.

The detection signal detected by the light receiver 114 is input to the video signal processing circuit 116. The video signal processing circuit 116 operates under the control of the CPU 108 to obtain a digital detection signal by sample-holding and AD converting the detection signal at a constant rate. Here, when the position (trajectory) of the tip 202a of the optical fiber 202 during the sampling period is determined, the spot formation position and the sampling point are determined almost uniquely. Here, the spot forming position refers to the position of a spot formed in the scanning region by the excitation light emitted when the tip 202a reaches an arbitrary position. The sampling point refers to a signal acquisition timing at which a return light (fluorescence) from the spot forming position is received by the light receiver 114 to obtain a digital detection signal. As will be described later, in the present embodiment, the locus of the tip 202a is measured in advance using the calibration unit 400, and the spot formation position and the sampling point are estimated based on the actual measurement result. Then, the position on the corresponding image (the pixel position of the endoscopic image displayed on the monitor 300) and the emission pattern of the excitation light are determined from the sampling point. The correspondence between the sampling point and the pixel position (pixel address) of the endoscopic image is stored in a remap table memory 119 connected to the video signal processing circuit 116 as a remap table. The correspondence between the sampling point and pixel address of the remapping table and the emission pattern of the excitation light is stored as emission pattern data in the emission pattern memory 122a built in the laser control circuit 122. Details regarding the storage of these data will be described later.

The video signal processing circuit 116 refers to the remapping table and assigns each digital detection signal obtained at each sampling point as corresponding pixel address data. Hereinafter, for convenience of explanation, the above allocation process is referred to as remapping. The video signal processing circuit 116 buffers an image signal constituted by a spatial arrangement of each point image in the image memory 118 according to the remapping result in a frame unit. The buffered signal is swept from the image memory 118 to the video signal output circuit 120 at a predetermined timing, and the video signal conforms to a predetermined standard such as NTSC (National Television System) Committee or PAL (Phase Alternate Line). And then output to the monitor 300. On the display screen of the monitor 300, a three-dimensional confocal image of a subject with high magnification and high resolution is displayed.

As shown in FIG. 3, the object is scanned spirally from the center of the scanning region toward the periphery in the XY direction (spiral scan). However, since the optical fiber 202 performs a resonant motion, The time taken for the scanning of rotation) is the same. For this reason, the irradiation density (irradiation energy per unit area) of the excitation light increases toward the center of the scanning region, and the decomposition of the phosphor progresses more rapidly, causing discoloration. As a result, there is a problem that the image becomes dark at the center of the observation area where the observation subject is located. Therefore, the scanning confocal endoscope system 1 according to the present embodiment is configured to appropriately suppress the fluorescence fading by appropriately controlling the emission pattern of the excitation light.

FIG. 4A is a diagram showing the movement of the tip 202a of the optical fiber 202. FIG. FIG. 4B is a diagram illustrating the intensity of excitation light emitted from the light source 102. Both the horizontal axes of FIGS. 4A and 4B are time axes. The vertical axis in FIG. 4A indicates the amount of displacement in the X (or Y) direction of the tip 202a with respect to the central axis AX. The vertical axis in FIG. 4B shows the intensity of the excitation light. As shown in FIG. 4B, the excitation light is emitted in a pulse shape for a predetermined period (hereinafter referred to as “pulse driving period”) from the start of the sampling period. The excitation light is continuously emitted after the pulse driving period has elapsed. As will be described later, the light emission pattern (light emission timing) of the excitation light during the pulse drive period is determined by the light emission pattern data generated based on the remapping table. In the present embodiment, the first 1/3 period of the sampling period is set as the pulse driving period as the light emission timing based on the result of the actual machine verification performed by the inventors. That is, the CPU 108 regards the first one-third period of the sampling period as a period in which fluorescent fading occurs (that is, the central portion of the scanning region), and controls the excitation light to be emitted in a pulsed manner. . Therefore, according to this embodiment, since the irradiation energy of the excitation light in the central portion of the scanning region is reduced as compared with the case of irradiating continuous excitation light, the decomposition of the phosphor does not proceed extremely. Fluorescence fading will be suppressed. Further, since the excitation light is continuously irradiated in the peripheral portion of the scanning region, there is no shortage of detection light in the peripheral portion of the observation region. By reducing the irradiation energy at the center of the scanning area where the irradiation energy of the excitation light is high, variations in irradiation energy per unit area within the scanning area are suppressed, and it is substantially uniform from the center to the periphery of the scanning area. It becomes possible to obtain a light amount of fluorescence. In the present embodiment, the emission of excitation light is controlled to stop during the braking period. Therefore, the phosphor is not decomposed by unnecessary excitation light during the braking period.

As described above, in the present embodiment, the emission pattern of the excitation light during the pulse drive period is determined by the emission pattern data generated based on the remapping table. Hereinafter, a method of creating the remapping table and the light emission pattern data of this embodiment will be described in detail.

The remap table is created by measuring the rotation locus of the tip 202a of the optical fiber 202 using the calibration unit 400 (FIG. 1). The measurement of the rotation trajectory of the tip 202a by the calibration unit 400 is a so-called calibration operation performed before using the scanning confocal endoscope system 1 of the present embodiment, and the calibration unit 400 is used as the confocal optical unit 204. This is done by placing it at the tip.

As shown in FIG. 1, the calibration unit 400 includes a PSD (Position Sensitive Detector) 402 and an amplifier 404. The PSD 402 is a semiconductor position detection element, and is an optical sensor that detects the position of excitation light emitted from the confocal optical unit 204. When the calibration unit 400 is disposed at the tip of the confocal optical unit 204, the PSD 402 is disposed to face the tip 202a of the optical fiber 202 of the confocal optical unit 204. In this arrangement state, the CPU 108 controls the light source 102 and the scanning driver 210 to continuously emit excitation light while scanning (rotating) the tip 202a of the optical fiber 202 in a spiral shape. The excitation light emitted from the tip 202a of the optical fiber 202 is received by the PSD 402, and the position information of the excitation light scanned in a spiral shape is sequentially converted into a current and output. The current output from the PSD 402 is converted into a voltage by the amplifier 404 and sent to the A / D 130 of the system main body 100. Then, the position information (voltage signal) of the excitation light is sampled by the A / D 130 at a predetermined sampling frequency (for example, 54 MHz) and then converted into a digital value. The position information of the excitation light converted into the digital value is sequentially stored in the CPU memory 110. Here, the sampling frequency is a frequency corresponding to the time taken to scan approximately one pixel of the endoscopic image in the peripheral portion of the scanning region.

Next, the CPU 108 creates a remap table by associating the position information of the excitation light stored in the CPU memory 110 with the image memory 118 and stores the remap table in the remap table memory 119. That is, the remapping table is a table describing the correspondence between the position information of the excitation light and the endoscopic image displayed on the monitor 300. For example, when the endoscopic image is 15 × 15 pixels, the remap table sequentially The relationship between the position of the sampled excitation light (sampling point) and the pixel position (raster coordinates) of the endoscopic image is as shown in FIG. Therefore, the CPU 108 obtains the pixel position (raster coordinates) of the endoscopic image from the sampling point based on this relationship, and creates a remap table. Further, in the present embodiment, light emission pattern data for emitting excitation light in a pulse form is created in order to prevent the sampling points from being concentrated at the center portion of the scanning region and causing discoloration.

FIG. 6 is a diagram for explaining the relationship between the remap table and the light emission pattern data of the central portion of the scanning area created by the CPU 108, and the relationship between the sampling point and the raster coordinates (pixel address of the endoscopic image). . FIG. 6A is an example of the remapping table and the light emission pattern data of this embodiment, and FIG. 6B shows the correspondence between 10 sampling points and raster coordinates that are continuous along the rotation locus. FIG. Here, the number assigned to each sampling point in FIG. 6B corresponds to the number of the sampling point in FIG. As shown in FIGS. 6A and 6B, sampling points 1 to 3 correspond to raster coordinates (6, 8), sampling points 4 and 5 correspond to raster coordinates (6, 7), and Sampling point 6 corresponds to raster coordinates (7, 7), sampling points 7, 8 correspond to raster coordinates (7, 6), and sampling points 9, 10 correspond to raster coordinates (8, 6). It will be described as being.

After obtaining the raster coordinates corresponding to each sampling point, the CPU 108 obtains the difference (delta coordinate) between the raster coordinates of each sampling point and the raster coordinates of the next sampling point. The CPU 108 completes the remap table based on the delta coordinates. For example, when the difference between the raster coordinates (6, 8) of the sampling point 3 and the raster coordinates (6, 7) of the sampling point 4 is obtained, the delta coordinate of the sampling point 3 is (0, −1), and the sampling point When the difference between the raster coordinate (6, 7) of 5 and the raster coordinate (7, 7) of the sampling point 6 is obtained, the delta coordinate of the sampling point 5 is (1, 0). In this way, by obtaining delta coordinates in order for successive sampling points, sampling points at which raster coordinates change (that is, sampling points located at boundaries with different pixels) are obtained. The completed remap table is sent to and stored in the remap table memory 119.

Next, the CPU 108 extracts sampling points having delta coordinates other than (0, 0) (that is, sampling points at which raster coordinates change), and sets only the light emission pattern data to “1” (in other words, In other cases, “0” is set for other cases) to generate light emission pattern data. That is, the light emission pattern data is “1” only at a sampling point where the raster coordinate changes (ie, a sampling point located at a boundary with a different pixel) among a plurality of consecutive sampling points having the same raster coordinate. It is data. A plurality of consecutive sampling points having the same raster coordinates are thinned out to one sampling point and assigned as light emission pattern data to the corresponding endoscopic image pixels (raster coordinates). In FIG. 6B, sampling points at which the light emission pattern data is “1” are indicated by black circles, and sampling points at which the light emission pattern data is “0” are indicated by white circles. The light emission pattern data generated in this way is sent to and stored in the light emission pattern memory 122a built in the laser control circuit 122. In the present embodiment, the excitation light in the pulse driving period (that is, the central portion of the scanning region) is irradiated in a pulsed manner with a laser driving signal based on the light emission pattern data, so that the fluorescence fading occurs at the central portion of the scanning region. It is prevented from occurring. In FIG. 6, for the sake of convenience of explanation, the remap table and the light emission pattern data in the central part of the scanning area are shown and described. However, the remap table and the light emission pattern data in the peripheral part of the scanning area are created in the same manner. Is done. However, since the peripheral portion of the scanning region is outside the pulse driving period, the light emission pattern data at each sampling point is all “1”.

When the remapping table and the light emission pattern data are completed, the normal confocal observation (endoscopic observation) can be performed by removing the calibration unit 400 from the tip of the confocal optical unit 204. That is, the CPU 108 controls the laser control circuit 122 so that excitation light corresponding to the light emission pattern data is emitted from the light source 102 while scanning (rotating) the tip 202a of the optical fiber 202 in a spiral shape. Specifically, the laser control circuit 122 controlled by the CPU 108 generates the laser drive signal while sequentially calling the light emission pattern data of each sampling point from the light emission pattern memory 122a, and supplies the laser drive signal to the light source 102 to thereby generate the excitation light. Perform on / off control.

FIG. 7 is a diagram schematically showing the relationship between the excitation light irradiated in a pulse shape based on the light emission pattern data and the raster coordinates (pixel address of the endoscope image). As described above, the light emission pattern data is data generated by thinning a plurality of consecutive sampling points having the same raster coordinates into one. Therefore, as shown in FIG. 7, as a result of the excitation light being irradiated based on the light emission pattern data, each pixel of the endoscopic image in the central portion of the scanning region has the number of rotation trajectories included in the pixel (that is, In other words, the excitation light of the pulse corresponding to the number of radial scanning lines) is irradiated. For example, in the case of FIG. 7, since the pixel at the raster coordinate (7, 6) includes only one scanning line, one pulse of excitation light is irradiated, and the pixel at the raster coordinate (8, 10) Since two scanning lines are included, two pulses of excitation light are emitted.

FIG. 8 is a timing chart showing the relationship between each sampling point and the laser drive signal. In FIG. 8, black circles indicate sampling points where the light emission pattern data is “1”, and white circles indicate sampling points where the light emission pattern data is “0”. As shown in FIG. 8, the laser drive signal of the present embodiment is a pulse signal having a certain width (for example, 5 sampling points) centered on the sampling point where the light emission pattern data is “1”. This is because when the excitation light is irradiated for a time corresponding to one sampling point, the irradiation time of the excitation light is about 18.5 ns (1/54 MHz), and a sufficient amount of fluorescence is obtained from the relationship with the reaction time of the fluorescent reagent. This is because it is difficult to obtain the sampling point and it is difficult to accurately irradiate the sampling point with the excitation light due to the delay time caused by the system. The delay time resulting from the system varies depending on the parts used, and the reaction time of the fluorescent reagent varies depending on the type and observation target. For this reason, the pulse width of the laser drive signal may be varied by the user operating the operation panel 124.

Also, it is conceivable that the signal delay time and the reaction time of the fluorescent reagent change due to changes in the system configuration and the fluorescent reagent. Therefore, in this embodiment, the user can arbitrarily advance the rise of the laser drive signal with respect to the sampling point by operating the operation panel 124 (that is, arbitrarily adjusting the timing at which the excitation light starts to be emitted). Can be configured).

The above is the description of the embodiments of the present invention. However, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the technical idea. For example, in the present embodiment, a fluorescent fading is generated in the first one-third period of the sampling period (that is, in a circle whose diameter is approximately 1/3 of the diameter of the scanning region) based on the result of actual machine verification. The pulse driving period is set as the region to be used. This pulse drive period may be set longer or shorter than the first 1/3 period of the sampling period depending on the degree of fluorescence fading. Further, the pulse driving period may be arbitrarily set by the user operating the operation panel 124.

In the present embodiment, the remapping table in the peripheral portion of the scanning area is configured to set all the light emission pattern data of each sampling point to “1”. However, the present invention is not limited to this configuration. The peripheral portion of the scanning region may be configured to continuously irradiate excitation light without setting light emission pattern data. With such a configuration, light emission pattern data only needs to be generated for sampling points corresponding to the pulse drive period, the processing can be made more efficient, and the data size of the remapping table can be reduced. .

In the present embodiment, the scanning confocal endoscope system has been described. However, the emission control of the excitation light in the present embodiment is another type exemplified in Patent Document 5 (for example, a color image can be taken). It can also be applied to a scanning endoscope system of a type). FIG. 10 is a schematic diagram illustrating a configuration of a part of the system main body 500 and the scanning endoscope 600 constituting a scanning endoscope system 1M according to another embodiment. FIG. 11 is a block diagram illustrating the configuration of the monitor 300 and the system main body 500. In FIG. 11, in order to clarify the connection relationship between the system main body 500 and the scanning endoscope 600, a part of the configuration of the scanning endoscope 600 is also schematically shown. In other embodiments, portions that overlap with the description of the present embodiment are omitted or simplified as appropriate.

As shown in FIG. 11, an optical connector 502 and an electrical connector 504 are provided on the front surface of the system main body 500, and an optical connector 602 and an electrical connector 604 are provided on the proximal end of the scanning endoscope 600. Yes. When the optical connector 602 is inserted into the optical connector 502, the system main body 500 and the scanning endoscope 600 are optically connected, and when the electric connector 604 is inserted into the electric connector 504, the system main body 500 and the scanning type are connected. The endoscope 600 is electrically connected. In FIG. 10, the connection portion between the optical connector 502 and the optical connector 602 is divided into three parts for easy understanding of the connection relationship between the system main body 500 and the scanning endoscope 600. .

The system main body 500 has a CPU 520 that comprehensively controls signal processing timing of various circuits. Further, the system main body 500 includes laser light sources 510R, 510G, which are capable of emitting light of each wavelength of R, G, and B (hereinafter referred to as “R light”, “G light”, and “B light”, respectively). 510B. Further, the laser light source 510S that emits light having a wavelength suitable for special light observation (hereinafter referred to as “special light”) is provided. Note that these four laser light sources may be replaced with a single fiber laser that emits supercontinuum light or the like having a wide band (a band including visible light and special light), for example. Further, the light source is not limited to the laser light source, and may be replaced with another form of light source such as an LED (Light-Emitting-Diode).

The system main body 500 has a laser control circuit 512 that controls the light emission of each of the laser light sources 510R, 510G, 510B, and 510S. The laser control circuit 512 includes a light emission pattern memory 512a. The light emission pattern memory 512a stores light emission pattern data similar to that of the present embodiment, created using the calibration unit 400 (not shown in FIGS. 10 and 11). The laser control circuit 512 performs light emission control of the laser light sources 510R, 510G, 510B, and 510S based on the light emission pattern data stored in the light emission pattern memory 512a, and synchronizes the R light, G light, B light, and special light. Inject at the timing. As an example, the laser control circuit 512 transmits light of each wavelength of R light, G light, B light, and special light for a predetermined period from the start of the sampling period (for example, the first 1/3 of the sampling period). During the remaining period of the sampling period after the lapse of the pulse driving period.

The R light, G light, B light, and special light emitted from each laser light source enter the optical coupler 514. The optical coupler 514 combines the incident light of each wavelength and makes it incident on the incident end 610 a of the single mode fiber 610 included in the scanning endoscope 600. The light incident on the single mode fiber 610 is transmitted through the single mode fiber 610 and is emitted from the exit end 610 b of the single mode fiber 610 disposed in the distal end portion 620 of the scanning endoscope 600.

FIG. 12 is a side sectional view showing the internal structure of the distal end portion 620 of the scanning endoscope 600. As shown in FIG. FIG. 13 is a perspective view showing the internal structure of the tip 620. A sheath 622 shown in FIG. 12 is a protective tube of the scanning endoscope 600 having flexibility. The sheath 622 has a shape extending from the distal end portion 620 to the optical connector 602, and protects various built-in components of the scanning endoscope 600. The outer diameter of the sheath 622 is much thinner than the outer diameter of a conventional electronic scope because the scanning endoscope 600 is configured not to mount an image sensor or the like. Therefore, the scanning endoscope 600 achieves even lower invasiveness than the conventional electronic scope.

A support 624 is attached inside the sheath 622. The tip portion 610c of the single mode fiber 610 is inserted through the through hole of the support 624 and supported in a cantilever state. A biaxial actuator 626 is also supported on the support 624. The scan driver 530 included in the system main body 500 applies the AC voltage X between the X-axis electrodes of the biaxial actuator 626C to resonate the piezoelectric body in the X direction, and has the same frequency as the AC voltage X and the phase is orthogonal. An alternating voltage Y is applied between the Y-axis electrodes to resonate the piezoelectric body in the Y direction. As a result, the exit end 610b of the single mode fiber 610 moves on the approximate XY plane so as to draw a spiral pattern around the central axis AX. During the sampling period, the light emitted from the emission end 610b spirals in a predetermined circular scanning region centered on the central axis AX via a condenser lens 628 attached to the distal end of the scanning endoscope 600. To scan.

The reflected component of the light that has scanned the subject enters the sheath 622 via the condenser lens 628. Here, in the sheath 622, a plurality of through holes are formed in an annular shape on the end surface 624 a of the support body 624. A detection fiber 630 is embedded in each through hole. The reflected light from the subject returned into the sheath 622 is incident on the incident end 630 a of each detection fiber 630. The reflected light incident on each incident end 630a is transmitted through the detection fiber 630 toward the end.

Although not shown in FIG. 13, the detection fibers 630 are bundled behind the support 624 to form an optical fiber bundle 630B. The optical fiber bundle 630B extends from the distal end portion 620 of the scanning endoscope 600 to the optical connector 602. The end of the optical fiber bundle 630B is accommodated in the optical connector 602. In the optical connector 602, the end of the optical fiber bundle 630B is optically coupled to one end of the wavelength selection fiber 650 by the optical circulator 640.

The reflected light transmitted through the fiber bundle 630B (detection fiber 630) is incident on the coupling end of the wavelength selection fiber 650 coupled to the end of the fiber bundle 630B by the optical circulator 640. The optical circulator 640 is configured to allow the reflected light from the fiber bundle 630B to enter only the wavelength selection fiber 650. That is, the reflected light from the fiber bundle 630B is configured not to enter the optical fiber 660 described later.

The wavelength selection fiber 650 is housed in an optical connector 602 so as to wind a station. In the light guide path of the wavelength selection fiber 650, fiber Bragg gratings 670R, 670G, and 670B corresponding to respective wavelengths of R (Red), G (Green), and B (Blue) are formed in this order from the coupling end side. Therefore, the reflected light that is incident on the wavelength selecting fiber 650 and transmitted is first caused by the fiber Bragg grating 670R to have strong back reflection with respect to the R component. That is, the fiber Bragg grating 670R reflects only the R light included in the reflected light, returns it to the coupling end side of the wavelength selection fiber 650, and transmits other components. The same optical action is caused in the fiber Bragg grating 670G and the fiber Bragg grating 670B. That is, only the G light is reflected in the fiber Bragg grating 670G and only the B light is reflected in the fiber Bragg grating 670B, and returned to the coupling end side of the wavelength selection fiber 650.

The fiber Bragg gratings 670R, 670G, and 670B are formed with positions determined so as to give a predetermined optical path difference to reflected light of R, G, and B wavelengths. Here, the optical circulator 640 is configured to allow light from the wavelength selection fiber 650 to enter only the optical fiber 660. That is, the light from the wavelength selection fiber 650 is configured not to enter the fiber bundle 630B. Therefore, the reflected lights of R, G, and B wavelengths that arrive at the coupling end of the wavelength selection fiber 650 with a predetermined time delay are sequentially incident on the optical fiber 660 while maintaining the predetermined time difference.

When the optical connector 502 and the optical connector 602 are connected, the end 660a of the optical fiber 660 is coupled to the photodetectors 544RGB via the coupling lens 542RGB included in the system main body 500. For this reason, the photodetectors 544RGB sequentially receive reflected light of R, G, and B wavelengths with a predetermined time difference.

On the other hand, the component corresponding to the special light included in the reflected light from the fiber bundle 630B is emitted from the end 650a of the wavelength selection fiber 650 without being reflected by any fiber Bragg grating during transmission through the wavelength selection fiber 650. The When the optical connector 602 is connected to the connector 502, the end 650a is optically coupled to the photodetector 544S via a coupling lens 542S included in the system main body 500. Therefore, the light detector 544S receives a component corresponding to the special light.

Each signal received and detected by the photodetectors 544RGB and 544S is input to the video signal processing circuit 550. The video signal processing circuit 550 operates under the control of the CPU 520, and obtains a digital detection signal by sample-holding and AD converting the detection signal at a constant rate.

The system main body 500 has a remap table memory 560. The remap table memory 560 stores a remap table that is created using the calibration unit 400 and is the same as that of the present embodiment. The video signal processing circuit 550 performs remapping based on the remapping table stored in the remapping table memory 560. Specifically, the video signal processing circuit 550 remaps the digital detection signals corresponding to the R, G, and B wavelengths detected by the photodetectors 544RGB and buffers them in the image memory 570 in units of frames. The buffered signal is swept from the image memory 570 to the video signal output circuit 580 at a predetermined timing, converted into a video signal conforming to a predetermined standard, and output to the monitor 300. As a result, a color image of the subject is displayed on the display screen of the monitor 300. Further, the video signal processing circuit 550 remaps the digital detection signal corresponding to the wavelength of the special light detected by the photodetector 544S, buffers the frame in the image memory 570, and passes the video signal output circuit 580 through the video signal output circuit 580. To the monitor 300. In this case, an emphasized image of the subject in which the living body corresponding to the wavelength of the special light is emphasized is displayed on the display screen of the monitor 300. Note that the color image and the emphasized image of the subject may be alternatively displayed on the monitor 300, or may be simultaneously displayed in two screen divisions.

According to another embodiment described above, scanning is performed by emitting laser light in a pulsed manner during a predetermined period (a pulse driving period, for example, the first 3 period of the sampling period) from the start of the sampling period. The irradiation energy of the laser beam is reduced in the central portion of the region as compared with the case where the continuous laser beam is irradiated. Therefore, for example, as a result of increasing the laser intensity in order to ensure the brightness of the peripheral part of the scanning region, avoiding the problem that the affected part located in the central part of the scanning region is irradiated with more laser light than necessary. Can do. Further, since the laser beam is continuously irradiated in the peripheral portion of the scanning region, there is no shortage of light amount in the peripheral portion. By reducing the irradiation energy in the central part of the scanning area where the laser beam irradiation energy is high, variations in the irradiation energy per unit area in the scanning area are suppressed, and the brightness is substantially uniform from the central part to the peripheral part. An endoscopic image can be obtained.

Claims (14)

  1. A first optical fiber that guides irradiation light supplied from a predetermined light source to an exit end, and exits the exit end to a subject;
    The irradiation light emitted from the exit end of the first optical fiber rotates at a constant speed from the center to the periphery within a substantially circular scanning region centered on the axis extending in the longitudinal direction of the first optical fiber. An optical fiber scanning means for rotationally driving the exit end of the first optical fiber in a spiral shape so as to rotate and scan in a spiral shape with a period;
    Light source control means for controlling on / off of the irradiation light;
    Image signal detection means for receiving return light returned from the subject irradiated with the irradiation light and detecting an image signal at a predetermined detection timing;
    Image generating means for generating an image of a subject using the detected image signal;
    With
    The light source control means includes
    When the irradiation light scans the central portion in the scanning region, the irradiation light is emitted in a pulse shape with a driving pulse having a predetermined pulse width, and the irradiation light scans the peripheral portion in the scanning region. Sometimes, the scanning endoscope system characterized by continuously emitting the irradiation light.
  2. The image generating means includes
    Assigning a two-dimensional pixel position according to the detection timing of the image signal, generating the image by arranging the image signal at the assigned pixel position,
    The light source control means includes
    When detection timings of a plurality of continuous image signals are assigned to the same two-dimensional pixel position, any one of the detection timings of the plurality of continuous image signals is used as a reference timing, and the detection timing is based on the reference timing. The scanning endoscope system according to claim 1, wherein a driving pulse is generated.
  3. The light source control means includes
    The scanning endoscope system according to claim 2, wherein the drive pulse is generated prior to the reference timing.
  4. The light source control means includes
    4. The scanning endoscope system according to claim 2, wherein the drive pulse is generated so as to include the reference timing.
  5. The light source control means includes
    A first input means for receiving input from a user;
    The time between the generation timing of the drive pulse and the reference timing is adjusted in accordance with a user input received by the first input means. The scanning endoscope system according to Item.
  6. The detection timing of the image signal is a constant cycle,
    The scanning endoscope system according to any one of claims 1 to 5, wherein a pulse width of the drive pulse is longer than a period of detection timing of the image signal.
  7. The light source control means includes
    A second input means for receiving an input from the user;
    The scanning endoscope according to any one of claims 1 to 6, wherein a pulse width of the drive pulse is adjusted according to a user input received by the second input unit. system.
  8. The diameter of the central part in the scanning region is
    The scanning endoscope system according to any one of claims 1 to 7, wherein the scanning endoscope system has a diameter of about 1/3 or less of the diameter of the scanning region.
  9. The optical fiber scanning means includes
    After rotating the exit end of the first optical fiber in a spiral shape, the rotational drive of the exit end of the first optical fiber is stopped for a predetermined period,
    The light source control means includes
    The scanning endoscope system according to any one of claims 1 to 8, wherein the emission of the irradiation light is stopped during the predetermined period.
  10. The irradiation light is excitation light,
    The image signal detecting means includes
    Fluorescence generated from the subject excited by the excitation light is received through a confocal pinhole disposed at a position conjugate with the condensing point of the excitation light, and an image signal is detected at the predetermined detection timing. The scanning endoscope system according to any one of claims 1 to 9, wherein the system is a scanning endoscope system.
  11. The confocal pinhole is
    The scanning endoscope system according to claim 10, wherein the scanning endoscope system is an exit end of the first optical fiber disposed at a position conjugate with a condensing point of the excitation light.
  12. The irradiation light is light including a wavelength in the visible region,
    The image signal detecting means includes
    The reflected light from a subject irradiated with light including a wavelength in the visible region is received, and an image signal is detected at the predetermined detection timing. The scanning endoscope system described in 1.
  13. The light including wavelengths in the visible region is light including wavelengths of R (Red), G (Green), and B (Blue),
    The image signal detection means includes
    13. The scanning type according to claim 12, wherein light of each wavelength of R, G, and B is separated from the reflected light from the subject and received, and an image signal is detected at the predetermined detection timing. Endoscope system.
  14. The image signal detecting means includes
    A second optical fiber into which the reflected light from the subject is incident;
    Different positions in the light guide path of the second optical fiber so that different optical path differences are given to the light of each wavelength of R, G, B, which is reflected light incident on the second optical fiber Wavelength selecting means corresponding to each wavelength of R, G, B arranged in
    A light receiving means for receiving light of each wavelength of R, G, B to which a different optical path difference is given by the wavelength selection means at a predetermined time difference;
    With
    14. The scanning endoscope system according to claim 13, wherein an image signal is detected at the predetermined detection timing from light of R, G, and B wavelengths received at the predetermined time difference.
PCT/JP2012/081894 2011-12-12 2012-12-10 Scanning endoscope system WO2013089053A1 (en)

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