JP2009237424A - Lens unit for probe and assembling method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve accuracy in assembling lenses constituting a lens unit for a confocal laser probe, and to improve the assembling efficiency, when coating an antireflection film. <P>SOLUTION: A confocal objective lens unit 21 to be attached to the tip portion of the confocal laser probe includes: a first lens 26, facing a portion to be observed; a second lens 27; a lens fixing frame 28; and a lens barrel 29. The first lens 26 is constituted, by cementing a semi-spherical lens part 31 to a planar lens part 32, located at the object side and having an outside diameter larger than that of the semi-spherical lens part 31. A flange part 32b is formed on the outer periphery of the planar lens part 32. A tapered surface 32d is formed on the flange part 32b. While the flange part 32b is held by a tool, the outer peripheral surface 32c of the flange part 32b is fitted into the inner peripheral surface 28a of the lens fixing frame 28, and the tapered surface 32d is brought into close contact with the tapered surface 28b of the inner peripheral surface 28a; and in this state, the first lens 26 is bonded to the lens-fixing frame 28. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a probe lens unit that is attached to a distal end portion of a confocal laser probe that is used by being inserted into a forceps channel of an endoscope, and an assembling method thereof.

  Conventionally, a single mode optical fiber and a lens unit disposed at the output end of the optical fiber are used to project a laser beam onto a living tissue in a body cavity (observed site of a subject), and the reflected light from the living tissue of the laser beam is reflected. Among these, there is known a confocal laser probe that extracts only reflected light on the object-side focal plane of the lens unit and obtains an observation image in a living tissue (see Patent Document 1). By scanning the living tissue with laser light, for example, a two-dimensional image having a depth of about 100 μm can be obtained from the surface of the biological mucous membrane.

  The confocal laser probe is used by being inserted into a forceps channel of an electronic endoscope (see Patent Document 2). Such a confocal laser probe needs to have a thin outer diameter in order to reduce the burden on the patient. In addition, the lens unit needs to have a high numerical aperture NA because the focal plane is a portion that has advanced in the depth direction from the surface of the biological mucous membrane. In particular, when the wavelength of the laser beam is a long wavelength, the numerical aperture NA must be increased in order to obtain a high-resolution observation image.

As described above, since a small diameter and a high numerical aperture NA are required, the lenses constituting the lens unit are miniaturized, and it is very difficult to accurately position a plurality of minute lenses. Yes. Conventionally, a lens assembling method using a dedicated jig has been proposed in order to accurately define the distance between lenses (see Patent Document 3). In addition, in order to efficiently extract the weak reflected light from the living tissue, a process of coating the lens with an antireflection film is performed.
JP 2004-240346 A JP 2000-121961 A JP 2007-298533 A

  Among the lenses constituting the lens unit of the confocal laser probe, the first lens facing the living tissue has the smallest diameter, and there is a lens having a diameter of 1 mm or less. Almost all lens surfaces of the first lens have an effective diameter. For this reason, it is difficult to accurately position the distance between the first lens and the second lens facing the first lens. In addition, there is no grip margin when coating the antireflection film, and coating is very difficult or enormously expensive.

  In Patent Document 3, since the lens fixing frame to which the first lens is fixed is attached to the outer end surface of the lens barrel, there is a concern that the lens fixing frame may come off the lens barrel and fall into the subject. The

  The present invention has been made in view of the above problems, and provides a probe lens unit that improves the assembly accuracy of the lenses constituting the lens unit of the probe and improves the workability when coating the antireflection film. The purpose is to do.

  Another object of the present invention is to provide a method for assembling a probe lens unit so that the lens fixing frame does not fall into the subject.

  In order to achieve the above object, the probe lens unit of the present invention is attached to the distal end portion of a confocal laser probe to be used by being inserted into a forceps channel of an endoscope, and faces the observation site of the subject. A probe lens unit comprising: a plurality of lenses including one lens; a lens fixing frame to which the first lens is fixed; and a lens barrel that holds the lens fixing frame and the plurality of lenses. A flange is provided on at least a part of the outer periphery.

  The first lens preferably includes a hemispherical lens portion and a flat lens portion that is disposed on the objective side, has an outer diameter larger than that of the hemispherical lens portion, and constitutes the flange portion. Further, it is preferable that the first lens is formed by joining the hemispherical lens portion and the flat lens portion. Furthermore, it is preferable that a positioning surface for positioning with the lens fixing frame is formed on the objective side of the collar portion. The positioning surface is preferably a tapered surface.

  A spacing ring that regulates the spacing between the surface of the first lens opposite to the objective side and the surface of the second lens facing the first lens is attached at a position facing the flange. Is preferred. In addition, a convex portion is formed on the outer peripheral surface of the lens fixing frame, and when the lens fixing frame is inserted from the side opposite to the objective side of the lens barrel, the convex portion is locked inside the lens barrel. It is preferable that the stop part is formed in the front-end | tip part of the said lens-barrel.

  The probe is preferably a confocal laser probe.

  The method for assembling a probe lens unit according to the present invention includes a plurality of first lenses that are attached to the distal end portion of a confocal laser probe that is inserted into a forceps channel of an endoscope and used to face an observation site of a subject. And a lens fixing frame to which the first lens is fixed; and a lens unit for a probe that includes the lens fixing frame and a lens barrel that holds the plurality of lenses. After fixing to the lens fixing frame, the lens fixing frame is inserted from the side opposite to the objective side of the lens barrel, and the outer periphery of the lens fixing frame is inserted into a locking portion formed inside the tip of the lens barrel. The convex part formed in the surface is latched, It is characterized by the above-mentioned.

  According to the probe lens unit of the present invention, since the flange portion is provided on at least a part of the outer periphery of the first lens facing the site to be observed, the distance between the second lens facing the first lens is defined. The collar can be used for the assembly, and the assembly accuracy is improved. Further, the collar portion can be used as a grip allowance when coating the antireflection film, and the workability when coating the antireflection film is improved.

  According to the method for assembling the probe lens unit of the present invention, after fixing the first lens to the lens fixing frame, the lens fixing frame is inserted from the side opposite to the objective side of the lens barrel, and the tip of the lens barrel is inserted. Since the convex portion formed on the outer peripheral surface of the lens fixing frame is locked to the locking portion formed on the inner side, the lens fixing frame is dropped into the subject even if the lens fixing frame is detached from the lens barrel. There is no.

  In FIG. 1, an endoscope system 2 is connected to an electronic endoscope 10, a confocal laser probe 11 that is used by being inserted into a forceps channel 19 of the electronic endoscope 10, and an electronic endoscope 10. It comprises an observation processor device 12 and a confocal observation processor device 13 connected to the confocal laser probe 11. The electronic endoscope 10 includes a flexible insertion portion 14 that is inserted into a body cavity, an operation portion 15 that is connected to a proximal end portion of the insertion portion 14, and a connector that is connected to a normal observation processor device 12. 16, and a universal cord 17 that connects the operation unit 15 and the connector 16.

  At the distal end of the insertion portion 14, a distal end portion 14 a in which a CCD (not shown) for intra-body cavity imaging is incorporated is continuously provided. A bending portion 14b connecting a plurality of bending pieces is provided behind the tip portion 14a. The bending portion 14b is bent in the vertical and horizontal directions when the angle knob 18 provided in the operation portion 15 is operated and the wire inserted in the insertion portion 14 is pushed and pulled. Thereby, the front-end | tip part 14a is orient | assigned to the desired direction in a body cavity.

  A forceps channel 19 is disposed inside the insertion portion 14. The forceps channel 19 continues from the forceps outlet 19a provided at the distal end portion 14a to the forceps inlet 19b provided at the operation portion 15.

  A known light source, a signal processing circuit, and the like are mounted on the normal observation processor 12. When the light source is turned on while the connector 16 is connected to the normal observation processor device 12, the light is transmitted to a light guide (not shown) piped from the connector 16 of the electronic endoscope 10 to the distal end portion 14a. Incident. Illumination light incident on the light guide is transmitted through the interior of the light guide, and is illuminated into the subject through an illumination window (not shown) provided on the front surface of the distal end portion 14a. This illumination light is reflected in the subject and imaged by the CCD built in the distal end portion 14a. The imaging signal output from the CCD is transmitted to the normal observation processor 12. The normal observation processor device 12 converts the imaging signal into image data and outputs the image data to the normal observation monitor 20. Thereby, the moving image and still image in the body cavity are displayed on the normal observation monitor 20.

  The confocal laser probe 11 is provided at the distal end portion and provided with a confocal objective lens unit 21 having a confocal objective optical system for obtaining an image of the observation site, and provided at the distal end portion. The connector 22 is connected to the observation processor device 13, and the cable 23 connects the confocal objective lens unit 21 and the connector 22. Inside the cable 23 is provided an optical fiber bundle 24 (see FIG. 2) formed by bundling a plurality of single mode optical fibers that transmit light. As described above, the confocal laser probe 11 is inserted from the forceps inlet 19b of the electronic endoscope, passes through the forceps channel 19, and from the forceps outlet 19a provided at the distal end portion 14a, the distal end of the confocal objective lens unit 21. The portion protrudes and an observation image in the subject can be obtained. When observation is performed, the distal end surface of the confocal objective lens unit 21 (the lens surface 32a of the first lens 26; see FIG. 3) is brought into contact with the surface of the living tissue.

  The confocal observation processor device 13 is equipped with a well-known laser light source, a processing circuit, and the like, and the laser when the connector 22 of the confocal laser probe 11 is connected to the confocal observation processor device 13. When the light source is turned on, the laser beam is transmitted through the optical fiber bundle 24 and emitted to the confocal objective lens unit 21. The laser light emitted from the single mode optical fiber is incident on the confocal objective optical system 30 (see FIG. 2) incorporated in the confocal objective lens unit 21. Then, the confocal objective optical system 30 focuses on the observation site. Next, the reflected light reflected from the site to be observed returns to the inside of the single mode optical fiber via the confocal objective optical system 30.

  The objective-side tip of the single mode optical fiber has an extremely small opening (core), and functions as a point light source and a diaphragm. Therefore, within the single mode optical fiber, the light reflected from the position conjugate with the objective-side tip of the single mode optical fiber (the position where the emitted light is focused at the observed site) out of the reflected light from the observed site Only incident. This incident light is transmitted through a single mode optical fiber and is input to the confocal observation processor 13. The confocal observation processor device 13 receives a point image of incident light obtained by scanning a laser beam on a site to be observed, converts it into an electrical signal, performs known signal processing, and performs a confocal observation monitor 25. Output to. As a result, a confocal scanning image (observation image) with high magnification and high resolution is displayed on the confocal observation monitor 25.

  2 and 3, the confocal objective lens unit 21 is opposed to the first lens 26 facing the observation site of the subject and the surface opposite to the objective side of the first lens 26 (lens surface 31a). A second lens 27, a lens fixing frame 28 to which the first lens 26 and the second lens 27 are fixed, and a lens barrel 29 that holds the lens fixing frame 28. The confocal objective lens unit 21 includes a confocal objective optical system 30 including a plurality of lenses (not shown) including the first lens 26 and the second lens 27. A plurality of lenses of the confocal objective optical system 30 including the first lens 26 and the second lens 27 are all held in the lens barrel 29.

  In FIG. 4, the first lens 26 is a bonded lens formed by joining a hemispherical lens portion 31 and a flat lens portion 32 disposed on the objective side and having a larger outer diameter than the hemispherical lens portion 31. . In the first lens 26, the lens surface 32a of the flat lens portion 32 is bonded to the objective side, and the lens surface 31a of the hemispherical lens portion 31 is bonded to the opposite side to the objective side. The outer periphery of the flat lens part 32 constitutes a flange part 32 b protruding from the outer diameter of the hemispherical lens part 31. The collar portion 32 b is provided on the entire outer periphery of the hemispherical lens portion 31. However, the present invention is not limited to this, and it is only necessary that a collar is provided on at least a part of the outer periphery of the hemispherical lens unit 31. The outer peripheral surface 32 c of the flange portion 32 b is formed so that its outer diameter is slightly smaller than the inner peripheral surface 28 a of the lens fixing frame 28.

  The outer diameter of the hemispherical lens portion 31 is an effective diameter at which almost all of them have an optical function. The optically functioning portion of the flat lens portion 32 is a portion that has a substantially mortar shape that is hung from the joint surface with the hemispherical lens portion 31 to the lens surface 32a, as shown by the dotted line in the figure. A portion that is not optically functional and deviates from the optically functional portion of the flat lens portion 32 constitutes the flange portion 32b.

  The flange portion 32b has a tapered surface 32d that extends from the outer peripheral surface 32c to the objective lens surface 32a. The tapered surface 32d is used as a positioning surface for positioning with the lens fixing frame 28.

  In FIG. 3, the lens fixing frame 28 has a substantially cylindrical shape, and a tapered surface 28b whose inner diameter gradually decreases toward the end surface on the objective side is formed on the inner peripheral surface 28a of the lens fixing frame 28. The first lens 26 is positioned with respect to the lens fixing frame 28 by contacting the tapered surface 28b of the lens fixing frame 28 and the tapered surface 32d of the flange 32b. The positioning surface for positioning the first lens 26 on the lens fixing frame 28 is not limited to such a tapered surface 32d, and a surface parallel to the objective lens surface 32a and having a step is provided on the flange 32b as a positioning surface. It may be formed.

  Further, the lens fixing frame 28 is formed with a convex portion 28c protruding in a stepped manner with a step parallel to the lens surface 32a at the end of the outer peripheral surface opposite to the objective side. The convex portion 28 c is locked to a locking portion 29 a formed at the distal end portion of the lens barrel 29. The convex portion 28c is not limited to a shape that protrudes stepwise from the outer peripheral surface, and may have a shape having a tapered surface on which the object-side surface is inclined.

  The distance between the lens surface 31a and the objective lens surface 27a of the second lens 27 is set at a predetermined distance h at a position on the surface opposite to the lens surface 32a of the flat lens portion 32 and facing the flange portion 32b. A spacing ring 33 is attached to regulate the distance between the two. The spacing ring 33 is in contact with the first lens 26 at a position facing the flange portion 32b, and has a flat surface 33a parallel to the lens surface 32a and a curved surface 33b in contact with the edge of the lens surface 27a. The spacing ring 33 is in contact with the first lens 26 at the flat surface 33a and the second lens 27 at the curved surface 33b. Since the first lens 26 is provided with the flange portion 32b, a sufficient contact area with the spacing ring 33 can be secured, so that the first lens 26 and the second lens 27 are positioned with high accuracy.

  A method of assembling the confocal objective lens unit 21 is shown in FIGS. First, before proceeding to the step shown in FIG. 5, the first lens 26 is coated with an antireflection film in order to efficiently extract the weak reflected light from the living tissue. In this coating process, the collar 32b is used as a grip allowance. Next, a process of fixing and holding the first lens 26, the interval ring 33, and the second lens 27 on the lens fixing frame 28 will be described with reference to FIGS. First, the lens surface 31a opposite to the objective side of the first lens 26 is formed on the first receiving surface 34a of the jig 34, and the collar portion 32b is formed on the second receiving surface 34b formed around the first receiving surface 34a. Close contact (see FIGS. 5A and 5B).

  Next, the lens fixing frame 28 is brought into close contact with the first lens 26 supported by the jig 34 (see FIGS. 5B and 6C). At this time, the outer peripheral surface 32c of the first lens 26 is fitted into the inner peripheral surface 28a of the lens fixing frame 28, and the tapered surface 32d of the first lens 26 is brought into close contact with the tapered surface 28b of the lens fixing frame 28 to fix the lens. The first lens 26 is positioned with respect to the frame 28. In this state, the first lens 26 is held by the lens fixing frame 28. Here, the first lens 26 and the lens fixing frame 28 are bonded and integrated. When integrating in this way, since the taper surface 32d of the first lens 26 and the taper surface 28b of the lens fixing frame 28 are positioned in close contact, the central axis O of the first lens 26 and the lens fixing frame 28 is determined. (See FIG. 2 and FIG. 3) can be matched with high accuracy.

  Next, the jig 34 is removed from the first lens 26 and the lens fixing frame 28 that holds the first lens 26. Then, the flat surface 33a of the spacing ring 33 is brought into close contact with the flange 32b of the first lens 26, and the curved surface 33b of the spacing ring 33 is brought into close contact with the edge of the objective lens surface 27a of the second lens 27. State (see FIG. 6D and FIG. 3).

  Thereby, the space | interval of the 1st lens 26 and the 2nd lens 27 can be set to the predetermined space | interval h. Then, the second lens 27 is held on the lens fixing frame 28 in a state where the interval is set to the predetermined interval h. Here, the second lens 27 is bonded to the lens fixing frame 28. Thereby, the 1st lens 26, the 2nd lens 27, the space | interval ring 33, and the lens fixing frame 28 are integrated.

  Next, a process of fixing the integrated first lens 26, second lens 27, spacing ring 33, and lens fixing frame 28 to the tip of the lens barrel 29 will be described with reference to FIG. First, the lens fixing frame 28 is inserted from the side opposite to the objective side of the lens barrel 29 (see FIG. 7A), and the convex portion 28c of the lens fixing frame 28 is formed at the tip of the lens barrel 29. It latches with the latching | locking part 29a. Then, in a state where the convex portion 28c is locked to the locking portion 29a, both are bonded and fixed to each other (see FIG. 7B). In this manner, the lens fixing frame 28 is locked and securely fixed to the locking portion 29a of the lens barrel 29, so that the lens fixing frame 28 does not fall off to the subject side. After the lens fixing frame 28 is bonded and fixed to the lens barrel 29, other lenses are assembled to complete the confocal objective lens unit 21.

  Since the first lens 26 is provided with the collar portion 32b as described above, it can be easily held by the jig 34 when the confocal objective lens unit 21 is assembled, and the first lens 26 and the lens fixing frame 28 can be held. Positioning (by the tapered surface 32d and the tapered surface 28b) and positioning between the first lens 26 and the second lens 27 (by the spacing ring 33) can be performed with high accuracy. Thereby, the assembly accuracy of the confocal objective optical system 30 constituting the confocal objective lens unit 21 is improved. In addition, when the anti-reflective film is coated on the lens surface of the first lens 26 before the assembly process of the confocal objective lens unit 21, the first lens 26 can be easily held with the collar 32b as a grip. Therefore, the workability in coating can be improved and the cost can be reduced.

  Since the first lens 26 is held by the spacing ring 33 at a position facing the collar portion 32b, the first lens 26 enters the lens barrel 29 even if the adhesion to the lens fixing frame 28 is removed. There is nothing. Further, the first lens 26 is prevented from dropping to the subject side by the tapered surface 28b. Further, since the lens fixing frame 28 is locked from the inner side of the lens barrel 29 by the convex portion 28c and the locking portion 29a, the lens fixing frame 28 may drop to the subject side as in the conventional case. Absent.

  Moreover, in the said embodiment, although the structure which united the processor apparatus and the light source device was mentioned as an example, this invention is not restricted to this, It is good also as a structure which made the processor apparatus and the light source device into a different body. . Furthermore, in the above-described embodiment, the electronic endoscope 10 is illustrated, but the present invention is not limited to this, and an ultrasonic endoscope in which an ultrasonic transducer is integrated at the distal end portion or an optical image guide is adopted. The present invention can also be applied to an endoscope (fiber scope) that observes the state of a subject.

It is an external view of an endoscope system. It is sectional drawing of the front-end | tip part of a confocal laser probe. It is sectional drawing to which the 1st lens periphery of the confocal laser probe was expanded. It is sectional drawing of a 1st lens. It is explanatory drawing which shows the assembly process which fixes a 1st lens and a lens fixing frame. It is explanatory drawing which shows the assembly process which adheres a 1st lens and a lens fixing frame, and a 2nd lens after the process of FIG. It is explanatory drawing which shows the assembly process of the objective lens unit for confocal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Endoscope system 10 Electronic endoscope 11 Confocal laser probe 12 Normal observation processor 13 Confocal observation processor 19 Forceps channel 21 Confocal objective lens unit 26 First lens 27 Second lens 28 Lens fixed frame 28c Convex part 29 Lens barrel 29a Locking part 31 Hemispherical lens part 32 Flat lens part 32b Gutter part 33 Space ring

Claims (9)

A plurality of lenses including a first lens that is attached to a distal end portion of a probe to be used by being inserted into a forceps channel of an endoscope, and that faces an observation site of a subject, and a lens fixing frame to which the first lens is fixed And a probe lens unit comprising the lens fixing frame and a lens barrel holding the plurality of lenses,
A probe lens unit, wherein a flange is provided on at least a part of the outer periphery of the first lens.   The first lens includes a hemispherical lens part, and a flat lens part that is disposed on the objective side and has an outer diameter larger than that of the hemispherical lens part and constitutes the flange part. The lens unit for probes according to 1.   The probe lens unit according to claim 2, wherein the first lens is formed by joining the hemispherical lens portion and the flat lens portion.   The probe lens unit according to any one of claims 1 to 3, wherein a positioning surface for positioning with the lens fixing frame is formed on the objective side of the flange portion.   5. The probe lens unit according to claim 4, wherein the positioning surface is a tapered surface.   A spacing ring that regulates the spacing between the surface of the first lens opposite to the objective side and the surface of the second lens facing the first lens is attached at a position facing the flange. The lens unit for a probe according to any one of claims 1 to 5. A convex portion is formed on the outer peripheral surface of the lens fixing frame,
When the lens fixing frame is inserted from the side opposite to the objective side of the lens barrel, a locking portion that locks the convex portion inside the lens barrel is formed at the tip of the lens barrel. The probe lens unit according to any one of claims 1 to 6.   8. The probe lens unit according to claim 1, wherein the probe is a confocal laser probe. A plurality of lenses including a first lens that is attached to a distal end portion of a confocal laser probe that is used by being inserted into a forceps channel of an endoscope and that faces an observation site of a subject, and the first lens are fixed. An assembly method of a lens unit for a probe comprising a lens fixing frame, and a lens barrel that holds the lens fixing frame and the plurality of lenses,
After fixing the first lens to the lens fixing frame, the lens fixing frame is inserted from the side opposite to the objective side of the lens barrel, and the locking portion formed on the inner side of the distal end portion of the lens barrel, A method of assembling a probe lens unit, wherein a convex portion formed on an outer peripheral surface of a lens fixing frame is locked.

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