JP2014068692A - Endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an endoscope capable of reducing an impact on a cover glass and preventing the cover glass from coming-off.SOLUTION: In an endoscope provided with an external cylinder, image acquisition means arranged in the external cylinder for emitting light into a body cavity and acquiring an image, and a cover glass attached to a leading end of the external cylinder, the cover glass is attached from the inside of the external cylinder, and has a convex cross-sectional shape consisting of a convex surface which is an apical surface of the endoscope and a concave surface formed so as to be lower than the convex surface and parallel to the convex surface. The concave surface is made to be an adhesive surface to fix the cover glass to the external cylinder.

Description

  The present invention relates to an endoscope for performing observation in a body cavity, and more particularly to a structure of a distal end portion of an endoscope.

  Conventionally, an endoscope system using an endoscope for diagnosing the inside of a body cavity of a patient is generally known and put into practical use. In recent years, a scanning endoscope system that scans an observation site with laser light guided by an optical fiber and receives the reflected light to form an image is also known. Furthermore, as one of the scanning endoscope systems, a living tissue to which a drug is administered is irradiated with laser light, and the fluorescence emitted from the living tissue is placed at a position conjugate with the focal position of the confocal optical system. A scanning confocal endoscope system is also proposed that enables the observation of the living tissue at a higher magnification than the observation image obtained by a normal endoscope optical system by extracting only the components through the pinhole. Has been.

  An example of such a scanning confocal endoscope system is disclosed in Patent Document 1. In the scanning confocal endoscope system described in Patent Document 1, the subject is three-dimensionally scanned by scanning the optical fiber in the XY direction and moving it back and forth in the Z direction. Thereby, a three-dimensional image with high magnification and high resolution can be obtained. When observation is performed using such a confocal endoscope system, the tip of the endoscope is brought into contact with the subject, and a plurality of subject images are acquired in the Z direction. Therefore, a cover glass is provided at the distal end of the endoscope so that the inner wall of the organ that is the subject may be directly touched.

Japanese Patent No. 4538297

  The endoscope described in Patent Document 1 has a structure in which a cover glass is attached to the outer frame of the distal end portion from the outside (that is, the subject side). For this reason, when the endoscope is used, the cover glass is easily exposed to an impact from the outside. Further, when the cover glass is attached from the outside in this way, the cover glass may fall out to the outside (that is, the body of the patient as the subject) when some impact is applied.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an endoscope capable of reducing the impact on the cover glass and preventing the dropout.

  In order to achieve the above object, an endoscope according to the present invention includes an outer cylinder, an image acquisition unit that is disposed in the outer cylinder, irradiates light into the body cavity, and acquires an image, and is externally provided from the inner side of the outer cylinder. A cover glass attached to the tip of the tube. Further, the cover glass has a convex cross-sectional shape composed of a convex surface that is a distal end surface of the endoscope and a concave surface that is lower than the convex surface and formed in parallel with the convex surface. It is an adhesive surface for fixing to the outer cylinder.

  With such a configuration, it is possible to reduce the impact on the cover glass, and it is possible to prevent the cover glass from dropping out to the outside (that is, the body of the subject). Furthermore, workability at the time of assembly is also improved by using the concave surface as an adhesive surface.

  Further, the convex surface may be a polished surface, and the concave surface may be a ground surface. With such a configuration, the surface that directly contacts the subject can be formed smoothly, and the adhesive strength on the adhesive surface with the outer cylinder can be increased.

  Further, the convex surface may protrude from the tip surface of the outer cylinder. With such a configuration, the convex surface of the cover glass can be appropriately brought into contact with the subject.

  The endoscope may further include a holding member that holds the cover glass with the outer cylinder, and the holding member may be an annular screw member in which a thread portion is formed on the outer peripheral surface. With such a configuration, it is possible to more firmly fix the cover glass, and it is possible to prevent not only falling outside but also falling outside.

  Further, the endoscope image acquisition means may be a confocal optical unit for acquiring a confocal image, and guides light incident on the incident end to the output end, from the output end to the subject. An outgoing optical fiber may also be included. Furthermore, the endoscope may further include an optical fiber scanning unit that drives the emission end of the optical fiber so that the light emitted from the emission end of the optical fiber scans the subject.

  ADVANTAGE OF THE INVENTION According to this invention, the endoscope which can reduce the impact to a cover glass and can prevent dropping is provided.

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 an enlarged view which shows the structure of the front-end | tip part of the confocal optical unit in 1st embodiment of this invention. It is an enlarged view which shows the structure of the front-end | tip part of the confocal optical unit in 2nd embodiment of this invention.

  Hereinafter, an endoscope according to an embodiment of the present invention will be described with reference to the drawings. In this embodiment, a case where the present invention is applied to a scanning confocal endoscope system will be described.

  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, and a monitor 300. The confocal observation using the scanning confocal endoscope system 1 is performed in a state where the distal end surface of the flexible tubular confocal probe 200 is applied to the subject.

  The system 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 video signal output. A circuit 120 is included. 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 that excites the drug administered into the body cavity of the patient in accordance with the drive control 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 tip of the optical fiber 202 is housed in a confocal optical unit 204 that is built into the tip 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 proximal end of the optical fiber 202, then transmitted through the optical fiber 202 and emitted from the distal end of the optical fiber 202.

  FIG. 2A is a diagram schematically showing the 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 of the optical fiber 202 (hereinafter referred to as “202a”) is housed and supported in the inner cylinder 204B through openings formed in the base end surfaces of the outer cylinder 204A and the inner cylinder 204B, and is located within the scanning confocal. It functions as a secondary point light source of the endoscope system 1. The position of the tip 202a, which is a point light source, periodically changes based on control by the CPU.

  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 system main body 100 and the confocal probe 200. 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.

  The scanning driver 210 generates a drive signal corresponding to the designated set value, and drives and controls the biaxial actuator 204C that 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 scanning driver 210 applies an AC voltage X between the X-axis electrodes of the biaxial actuator 204C to resonate the piezoelectric body in the X direction, and also applies an AC voltage Y having the same frequency as that of the AC voltage X and orthogonal in phase. Applied between the Y-axis electrodes, the piezoelectric body resonates 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. Rotate 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 emitted from the tip 202a of the optical fiber 202 in accordance with the laser drive signal supplied from the CPU 108 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 in a predetermined light emission pattern. Hereinafter, for convenience of explanation, this period is referred to as a “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 circular motion of the tip 202a on the XY approximate plane converges as the vibration of the optical fiber 202 is attenuated, and stops on the central axis AX after a predetermined time. Hereinafter, for convenience of explanation, a period from the end of the sampling period until the tip 202a stops on the central axis AX (more precisely, in order to guarantee the stop on the central axis AX, calculation required to stop) The period of time slightly longer than the above time) is referred to as a “braking period”. The period corresponding to one frame is composed of one sampling period and one braking period. In order to shorten the braking period, the reverse torque may be applied to the biaxial actuator 204C in the initial stage of the braking period to positively apply the braking torque.

  An objective optical system 204D is installed in front of the tip 202a of the optical fiber 202. The objective optical system 204D includes a plurality of optical lenses, and is held by the inner cylinder 204B via a lens frame (not shown). Therefore, the optical lens group held by the lens frame slides in the Z direction integrally with the inner cylinder 204B inside the outer cylinder 204A. A cover glass 205 is held at the forefront of the outer cylinder 204A (that is, in front of the objective optical system 204D).

  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 sandwiched 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 energizes and heats the shape memory alloy 204F to control the expansion / contraction amount. 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.

  The excitation light emitted from the tip 202a of the optical fiber 202 is transmitted through the objective optical system 204D and the cover glass 205 to form 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, which 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 scattering component (fluorescence) of 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 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. The light receiver 114 may be a high-sensitivity photodetector such as a photomultiplier tube in order to detect weak light with low noise.

  The detection signal detected by the light receiver 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 imaging period is determined, the spot forming position in the observation region (scanning region) corresponding to the position and the return light from the spot forming position are detected. Thus, the signal acquisition timing for obtaining the digital detection signal is almost uniquely determined. In the present embodiment, the spot formation position is estimated from the signal acquisition timing in advance with reference to the actual measurement result using a calibration jig or the like, and the position on the image corresponding to the estimated position is determined. The CPU memory 110 stores a remapping table that associates the determined signal acquisition timing with the pixel position (pixel address).

  The video signal processing circuit 116 refers to the remapping table and assigns the point image represented by each digital detection signal to the pixel address according to the signal acquisition timing. Hereinafter, for convenience of explanation, the above assignment work 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 Alternating Line). To be 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.

  Next, the structure of the tip of the confocal optical unit 204 in the first embodiment will be described with reference to FIG. FIG. 4 is an enlarged view showing the structure of the tip of the confocal optical unit 204. As shown in FIG. 4, a cover glass 205 is attached to the front end surface of the confocal optical unit 204. The cover glass 205 of the present embodiment is a circular glass having a convex cross-sectional shape composed of a convex surface 205A serving as the tip surface of the confocal optical unit 204 and a concave surface 205B formed around the convex surface 205A. It is attached from the inside of the tube 204A.

  The convex surface 205A is a surface that has an outer diameter that is substantially the same as the inner diameter of the opening of the outer cylinder 204A and is arranged to close the opening of the outer cylinder 204A. At the time of observation, the excitation light emitted from the tip 202a of the optical fiber 202 passes through the convex surface 205A. Further, the convex surface 205A is formed so as to protrude from the distal end surface of the outer cylinder 204A, and the convex surface 205A directly contacts a subject (such as an inner wall of an organ) during observation. Therefore, the convex surface 205A is a smooth polished surface.

  The concave surface 205B is a surface that is one step lower than the convex surface 205A and formed in parallel with the convex surface 205A. In the present embodiment, the cover glass 205 is fixed to the outer cylinder 204A by applying an adhesive to the concave surface 205B and bringing it into contact with the holding part 204G on the inner wall of the distal end portion of the outer cylinder 204A. Therefore, the concave surface 205B is a slit surface on which fine irregularities are formed on the surface so as to increase the adhesive strength.

  As described above, in this embodiment, by providing the adhesive surface (concave surface 205B) of the cover glass 205 on the inner side (holding portion 204G) of the outer cylinder 204A, the impact applied during observation can be absorbed by the outer cylinder 204A. Thus, the impact on the cover glass 205 can be reduced. In addition, the cover glass 205 is prevented from falling outside (that is, the body of the subject). Furthermore, by using the concave surface 205B formed as a flat surface as an adhesive application surface, the adhesive can be applied relatively easily, and the assembly workability is improved.

  Next, the structure of the tip of the confocal optical unit 2041 in the second embodiment will be described with reference to FIG. FIG. 5 is an enlarged view showing the structure of the tip of the confocal optical unit 2041. The confocal optical unit 2041 of this embodiment has substantially the same configuration as that of the first embodiment except that the holding member 206 is provided. Therefore, the same reference numerals are given to the same constituent members.

  As shown in FIG. 5, a cover glass 205 is attached to the tip of the confocal optical unit 2041 as in the first embodiment. Since the shape of the cover glass 205, the configuration of the convex surface 205A and the concave surface 205B, and the attachment to the outer cylinder 2041A are the same as in the first embodiment, the description thereof is omitted. In the present embodiment, a holding member 206 is further provided to hold the cover glass 205 from the inner side (objective optical system 204D side) to the outer side (subject side) and hold it with the outer cylinder 2041A. The holding member 206 is an annular screw member having a screw portion 206A on the outer peripheral surface. Further, in the present embodiment, screw portions 2041S are also formed on the inner peripheral surface of the outer cylinder 2041A, and the cover glass 205 is held by tightening these screw portions. Thereby, the cover glass 205 is firmly fixed, and the movement of the cover glass 205 in the Z direction is suppressed.

  In the present embodiment, the same effect as in the first embodiment can be obtained, and the cover glass 205 can be more reliably fixed by providing the holding member 206. Further, it is possible to prevent not only the cover glass 205 from dropping to the outside but also the inside from falling off.

  The above is the description of the embodiment of the present invention. The present invention is not limited to the above-described configuration, and various modifications can be made within the scope of the technical idea of the present invention. First, in the above-described embodiment, the case where the present invention is applied to a scanning confocal endoscope has been described. However, the present invention is not limited to this, and the present invention is also applied to other endoscopes including a cover glass at a distal end portion. The invention can be applied.

  In the above embodiment, the cover glass 205 is directly attached to the inner wall of the outer cylinder 204A. However, a holding frame for attaching the cover glass 205 may be separately provided in the outer cylinder 204A.

1 Scanning Confocal Endoscope System 100 System Main Body 102 Light Source 104 Optical Demultiplexer / Multiplexer 106 Damper 108 CPU
110 CPU memory 112 Optical fiber 114 Light receiver 116 Video signal processing circuit 118 Image memory 120 Video signal output circuit 200 Confocal probe 202 Optical fibers 204 and 2041 Confocal optical unit 205 Cover glass 206 Sub CPU
208 Sub memory 210 Scan driver

Claims (7)

An outer cylinder,
An image acquisition means arranged in the outer cylinder, for acquiring an image by irradiating light into a body cavity;
A cover glass attached to the tip of the outer cylinder from the inside of the outer cylinder,
The cover glass has a convex cross-sectional shape composed of a convex surface that is a distal end surface of an endoscope and a concave surface that is lower than the convex surface and formed in parallel with the convex surface,
The endoscope, wherein the concave surface is an adhesive surface for fixing the cover glass to the outer cylinder.   The endoscope according to claim 1, wherein the convex surface is a polished surface and the concave surface is a slit surface.   The endoscope according to claim 1, wherein the convex surface protrudes more than a front end surface of the outer cylinder.   The endoscope according to any one of claims 1 to 3, further comprising a holding member that holds the cover glass with the outer cylinder.   The endoscope according to claim 4, wherein the holding member is an annular screw member in which a thread portion is formed on an outer peripheral surface.   The endoscope according to any one of claims 1 to 5, wherein the image acquisition unit is a confocal optical unit for acquiring a confocal image. The image acquisition means includes an optical fiber that guides the light incident on the incident end to the exit end and exits the exit end to the subject.
The endoscope further includes an optical fiber scanning unit that drives the emission end of the optical fiber so that the light emitted from the emission end of the optical fiber scans on a subject. The endoscope according to any one of 1 to 6.

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