JP2006288779A - Objective lens portion of endoscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an objective lens portion of an endoscope which can be correctly and reliably fixed to an object lens-barrel in a short processing time with correctly aligning its shading mask with the non-circular cross-sectional shape of an observation image projection optical path. <P>SOLUTION: The object lens-barrel 11 and the shading mask 15 are provided with shading mask positioning means 15a and 16 for positioning the shading mask 15 with respect to the object lens-barrel 11 in the axial direction. The shading mask 15 is mechanically fixed to the object lens-barrel 11 so that it may not move in the axial direction in the object lens-barrel 11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an endoscope objective lens portion built in the distal end of an insertion portion of an endoscope.

  An objective lens is built into the distal end of the endoscope insertion part, and in order to prevent the occurrence of flare, ghost, etc., a light shielding mask for blocking unnecessary light around the observation image projection optical path is provided in the latter half of the objective tube. Attached to the part.

In such an objective lens portion of an endoscope, conventionally, a light shielding mask is directly bonded and fixed to the objective lens barrel, or two optical components sandwiching the light shielding mask are bonded and fixed in the objective lens barrel. (For example, Patent Documents 1 and 2).
JP-A-8-248327 JP-A-6-269405

However, when the light shielding mask is fixed by adhesion, in the manufacturing process, the process may be interrupted for a long time due to waiting for the adhesive to cure, which may be one of the causes of increased costs.
In addition, in an endoscope in which the imaging surface of the solid-state imaging device on which the observation image is projected is formed in a non-circular shape such as a square, the cross-sectional shape of the observation image projection optical path is correspondingly non-circular, In the objective lens part of a conventional endoscope, the orientation of the light-shielding mask was adjusted by eyesight when fixing the adhesive, so that the mask shape shifts with respect to the observation image projection optical path and unnecessary light partially passes. On the other hand, part of the necessary light may be cut, causing the quality of the observed image to deteriorate.

  Therefore, the present invention provides an objective lens for an endoscope that can accurately and reliably fix a light-shielding mask to an objective barrel in a short process time in accordance with the cross-sectional shape of the observation image projection optical path having a non-circular cross-sectional shape. The purpose is to provide a department.

  In order to achieve the above object, the objective lens portion of the endoscope of the present invention has a non-circular cross-sectional observation image projection optical path in the latter half of the objective tube having a circular cross-section built in the distal end of the insertion portion. In the objective lens portion of the endoscope to which a light shielding mask for shielding unnecessary light in the periphery of the endoscope is attached, the objective lens barrel and the light shielding mask are positioned in the direction around the axis of the light shielding mask with respect to the objective lens barrel. A light shielding mask positioning means is provided, and the light shielding mask is mechanically fixed to the objective barrel so as not to move in the axial direction in the objective barrel.

  The light shielding mask positioning means is constituted by a protrusion protruding outward from the circular outer edge portion of the light shielding mask and an engagement groove formed in the objective barrel so that the protrusion of the light shielding mask engages. In this case, the engagement groove may be formed in a shape opened to the rear end side of the objective barrel.

  Further, the rear end edge of the objective tube may be caulked inward, whereby the light-shielding mask may be mechanically fixed to the objective tube. In this case, the objective lens at the rear end of the objective lens is the objective lens. The light shielding mask is disposed in the rear end portion of the lens barrel, adjacent to the front side of the objective lens at the rear end, and the rear edge of the objective lens barrel is caulked, so that the light shielding mask is placed in the objective lens barrel. It may be pressed and fixed.

  In addition, the imaging surface of the solid-state imaging device is disposed at the rear end position of the observation image projection optical path, and the imaging unit for positioning the imaging unit holding member that holds the solid-state imaging device in the direction around the axis with respect to the objective lens barrel A holding member positioning unit may be provided, and in that case, the engagement groove may be formed in the objective barrel so as to correspond to the position of the imaging unit holding member positioning unit.

  According to the present invention, the light shielding mask is provided with a light shielding mask positioning means for positioning the light shielding mask in the direction around the axis of the light shielding mask with respect to the object lens barrel, so that the light shielding mask has a noncircular cross-sectional shape. It is possible to accurately match the cross-sectional shape of the observation image projection optical path, and further, the light shielding mask is mechanically fixed to the objective tube so as not to move in the axial direction in the objective lens tube. Can be securely fixed to the objective tube.

  An endoscope in which a light-shielding mask for blocking unnecessary light around the non-circular cross-sectional observation image projection optical path is attached to the latter half of the objective tube having a circular cross-sectional shape built in the distal end of the insertion portion. In the objective lens section, the objective lens barrel and the light shielding mask are provided with light shielding mask positioning means for positioning the light shielding mask in the direction around the axis of the light shielding mask with respect to the objective lens barrel, and the light shielding mask is arranged in the axial direction in the objective lens barrel. It is mechanically fixed to the objective tube so as not to move.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a distal end portion of an insertion portion 1 of an endoscope, and an observation window 3 is arranged on a distal end surface of a distal end portion main body 2 connected to the distal end of the insertion portion 1.

  A cover lens 4 made of a concave lens is attached to the observation window 3 of this embodiment, and the object is projected by the objective lens 5 disposed in the back thereof (that is, at the rear end position of the observation image projection optical path). An imaging surface 6a of the solid-state imaging device 6 is disposed.

  The imaging surface 6a of the solid-state imaging element 6 has a non-circular shape such as a rectangle or a square, and the cross-sectional shape of the observation image projection optical path in the objective lens 5 is also correspondingly non-circular. Reference numeral 7 denotes a YAG laser cut filter, and 8 denotes a cover glass of the solid-state image sensor 6.

  Reference numeral 9 denotes a signal cable through which an imaging signal of an endoscopic observation image captured by the solid-state image sensor 6 is transmitted, and is inserted through the entire length of the insertion portion 1. Reference numeral 10 denotes a circuit sealing portion in which an electronic component or the like connected between the solid-state imaging device 6 and the signal cable 9 is sealed.

  Reference numeral 11 denotes an objective barrel in which the cover lens 4 and the objective lens 5 are fitted and fixed from the front and the rear, and is formed in a cylindrical shape in which a step is formed on each of the inner surface and the outer surface. It is built in the formed objective part accommodation hole 2a. Reference numeral 12 denotes an aperture stop, and reference numeral 13 denotes a spacer ring for restricting a distance between the objective lens 5a at the rear end of the objective lens 5 and the objective lens at the front side thereof.

  Between the spacer ring 13 and the objective lens 5a at the rear end, a light shielding mask 15 for blocking unnecessary light around the observation image projection optical path in the objective lens 5 is disposed. As shown in FIG. 2 illustrating the II-II cross section in FIG. 1, the light shielding mask 15 is formed in a non-circular shape in which the mask edge 15i matches the cross sectional shape of the observation image projection optical path at that position, and the outer edge 15o It is formed in a circular shape that fits to the inner peripheral surface near the rear end of the objective tube 11.

  On the outer edge portion of the light shielding mask 15, a projection 15 a for positioning the light shielding mask 15 with respect to the objective lens barrel 11 in the direction around the axis is formed. As shown in FIG. 3, an engagement groove 16 in which the projection 15 a of the light shielding mask 15 engages without rattling is formed in the objective barrel 11. The engagement groove 16 is formed in a linear groove shape with one end opened on the rear end side of the objective barrel 11.

  Therefore, when the projection 15a is engaged with the engagement groove 16 and the light shielding mask 15 is fitted into the objective barrel 11 from the rear, the mask edge 15i is oriented in a predetermined direction due to the engagement between the projection 15a and the engagement groove 16. It becomes a state regulated in the direction.

  Referring back to FIG. 1, the objective lens 11 is fitted into the objective tube 11 from the rear at the time of assembly. The objective lens 5 except the aperture stop 12, the rear end objective lens 5 a, the spacer ring 13, the light shielding mask 15, and the rear end objective. In this order, the rear end edge 11a of the objective tube 11 is caulked inward and pressed against the rear end portion of the rear end objective lens 5a, so that the aperture stop 12, the objective lens 5, and the spacer ring 13 are placed. The light shielding mask 15 and the objective lens 5a at the rear end are mechanically pressed and fixed in the objective barrel 11.

  Therefore, in the assembling process, there is no need for the time for waiting for the adhesive to cure, and the light shielding mask 15 is pressed and fixed to the spacer ring 13 by the objective lens 5a at the rear end.

  The solid-state imaging device 6 arranged on the rear side is fixed together with the YAG laser cut filter 7 and the like in the middle portion of the imaging unit holding cylinder 18 having a square cross section with the direction of the axis around the imaging unit holding cylinder 18. As shown in FIG. 4, an imaging unit connection frame 19 for connecting to the objective barrel 11 is integrally fixed to the most distal portion of the imaging unit holding cylinder 18.

  A pair of parallel projections 21 project from the upper and lower (or left and right) both end positions of the front surface of the imaging unit connection frame 19, and the pair of parallel flat portions 20 that are perfectly engaged with the projections are VV cross sections in FIG. As shown in FIGS. 5 and 3, etc., these are formed in parallel with the outer peripheral surface of the objective barrel 11 so as to correspond to the positions of the engagement grooves 16.

  Therefore, as shown in FIG. 1, the imaging unit holding cylinder 18 is attached to the objective mirror by engaging the parallel plane part 20 and the parallel projection 21 to connect and fix the objective lens barrel 11 and the imaging part connection frame 19 together. The lens 11 is positioned and coupled and fixed so as not to rotate relative to the cylinder 11 around the axis, and the mask edge 15 i of the light shielding mask 15 in the objective barrel 11 and the imaging surface 6 a in the imaging unit holding cylinder 18. Are fixedly set in a state in which the rotation direction around the axis is regulated in a corresponding manner.

  As a result, the mask edge 15i of the light shielding mask 15 is assembled so as to coincide with the observation image projection optical path having a cross-sectional shape corresponding to the shape of the imaging surface 6a of the solid-state imaging device 6, thereby obtaining a high-quality endoscope observation image. Can do.

It is side surface sectional drawing of the insertion part front-end | tip of the endoscope of the Example of this invention. It is sectional drawing (II-II sectional drawing in FIG. 1) of the light shielding mask of the Example of this invention. It is a perspective view of the objective lens tube and light shielding mask of the Example of this invention. It is a perspective view in the state where the image pick-up part holding cylinder and image pick-up part connection frame of the example of the present invention were integrated. It is VV sectional drawing in FIG. 1 of the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insertion part 5 Objective lens 5a Rear end objective lens 6 Solid-state image sensor 6a Imaging surface 11 Objective lens barrel 11a Rear end edge 15 Light shielding mask 15a Protrusion (light shielding mask positioning means)
16 Engaging groove (shading mask positioning means)
18 Imaging unit holding cylinder (Imaging unit holding member)
19 Imaging unit connection frame 20 Parallel plane part (imaging unit holding member positioning means)
21 Parallel projection (image-pickup holding member positioning means)

Claims (7)

An endoscope in which a light-shielding mask for blocking unnecessary light around the non-circular cross-sectional observation image projection optical path is attached to the latter half of the objective tube having a circular cross-sectional shape built in the distal end of the insertion portion. In the objective lens section,
Provided with the light shielding mask positioning means for positioning in the direction around the axis of the light shielding mask with respect to the objective lens barrel on the objective lens barrel and the light shielding mask,
An objective lens unit of an endoscope, wherein the light shielding mask is mechanically fixed to the objective barrel so as not to move in the axial direction in the objective barrel.   The light shielding mask positioning means includes a protrusion protruding outward from a circular outer edge portion of the light shielding mask and an engagement groove formed in the objective barrel so that the protrusion of the light shielding mask engages. The objective lens part of the endoscope according to claim 1.   The objective lens part of the endoscope according to claim 2, wherein the engagement groove is formed in a shape opened to a rear end side of the objective lens barrel.   The objective lens part of the endoscope according to claim 1, 2, or 3, wherein a rear end edge of the objective barrel is caulked inwardly, whereby the light shielding mask is mechanically fixed to the objective barrel.   The objective lens at the rear end of the objective lens is disposed in the rear end portion of the objective lens barrel, and the light shielding mask is disposed adjacent to the front side of the objective lens at the rear end. The objective lens part of the endoscope according to claim 4, wherein the light shielding mask is pressed and fixed in the objective barrel by crimping an edge.   An imaging unit in which an imaging surface of a solid-state imaging device is arranged at the rear end position of the observation image projection optical path, and an imaging unit holding member that holds the solid-state imaging device is positioned in the direction around the axis line with respect to the objective barrel The objective lens part of the endoscope according to any one of claims 1 to 5, wherein holding member positioning means is provided.   The objective lens part of the endoscope according to claim 6, wherein the engagement groove is formed in the objective barrel so as to correspond in position to the imaging unit holding member positioning unit.

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