JP2006288821A - Electronic endoscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic endoscope where a diameter can be reduced by making a space through which a luminous flux pass small. <P>SOLUTION: The electronic endoscope is provided with: two objective optical system which are for forming the optical image of a patient and which are arrayed so that the optical axes of them are parallel to each other; a single CCD which is arranged on the image forming surfaces of the two objective optical system and where two effective imaging ranges of respectively carrying out photoelectric conversion to two optical images image-formed by each objective optical system are rectangles respectively having long edges and short edges; and beam guide channels 32e and 32f which are for making two luminous fluxes concerning two optical images image-formed on the CCD by the two objective optical systems pass through respectively and where the shape of a cross section vertical to an optical axis is nearly an ellipse which does not allow a luminous flux which can reach the vicinity of outsides of the short edges of the effective imaging ranges to pass through. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electronic endoscope configured to photoelectrically convert an optical image formed by an objective optical system using an imaging device.

  Endoscopes are used in various fields such as medicine and industry, but electronic endoscopes using image sensors have been widely used due to recent advances in electronic technology.

  This electronic endoscope includes an elongated insertion portion for insertion into a subject, and the distal end portion of the insertion portion is illuminated by an illumination optical system for illuminating a region to be examined, or by this illumination optical system. An imaging unit or the like for imaging the detected region is provided. Of these, the imaging unit is generally configured to include an objective optical system for imaging a subject image and an imaging element such as a CCD disposed at the imaging position of the objective optical system. Yes.

  Incidentally, some electronic endoscopes include a plurality of objective optical systems, and an optical image formed by the plurality of objective optical systems is photoelectrically converted by one or a plurality of imaging elements. Thus, a plurality of images can be obtained. Such an electronic endoscope is used for various applications, for example, for constructing a stereoscopic image, or for obtaining a wide-field image with one objective optical system and the other. There is a method of obtaining an enlarged image with an objective optical system.

  Various techniques for reducing the diameter of an endoscope having such a plurality of objective optical systems have been proposed.

  For example, Japanese Patent Laid-Open No. 2001-2221961 discloses a binocular optical adapter that is applied to an endoscope having one CCD, and includes two optical systems arranged in parallel. A binocular optical adapter is described in which an optical image by an optical system is formed at different positions on the image plane of the one CCD. Further, in this publication, a lens disposed on the rear end side on each optical path in the two optical systems is a D-cut lens (the shape of the letter “D” is abbreviated when viewed from the optical axis direction). In other words, a technique is described in which the distance between two optical systems is shortened by making the cut surfaces face each other, thereby reducing the size.

  Such a technique will be described with reference to FIGS.

  FIG. 17 is a sectional view showing a configuration of an imaging unit configured to form a plurality of images on one CCD by two objective optical systems, and a diagram showing an imaging range on the CCD. FIG. The figure which shows the light ray height and imaging range of the light beam by two objective optical systems, FIG. 19 is FF sectional drawing which shows the light guide path and light ray height in an imaging unit.

  As shown in FIG. 17A, the imaging unit 101 includes a first optical system 103 designed to have a wide field angle (wide angle) and a first optical system 103 designed to have a narrow field angle (enlargement). 2 optical systems 104, and these optical systems 103 and 104 are respectively attached to the lens frame 102. The optical system 103 includes a first lens 103a, a second lens 103b, a third lens 103c, and a fourth lens 103d. The optical system 104 includes a first lens 104a, a second lens 104b, and a third lens 104c. It is comprised. The rear end side lenses 103d and 104c in the optical systems 103 and 104 are configured as D-cut lenses.

  The lens frame 102 is supported by a support frame 105, and a cover glass 106 is fixed to the support frame 105. A CCD 107 is disposed behind the cover glass 106 in the optical path.

  The lens frame 102 is formed with a light guide path 102e for the optical system 103 and a light guide path 102f for the optical system 104, respectively. The light guide path 102e constitutes an optical path between the third lens 103c in the optical system 103 and the fourth lens 103d which is a D-cut lens, and the light guide path 102f is connected to the second lens 104b and D in the optical system 104. This constitutes an optical path between the third lens 104c, which is a cut lens. As shown in FIG. 19, the light guide paths 102e and 102f each have a circular cross section perpendicular to the optical axis. The light beam heights of the optical systems 103 and 104 are substantially the same as the cross sections of the light guide paths 102e and 102f, as indicated by the dotted line hatching in the figure.

Such a light beam having a light beam height has a light beam height as shown in a portion surrounded by a dotted line in FIGS. 17B and 18 on the image forming surface 107 a of the CCD 107. The effective imaging range of the optical image by the optical system 103 is indicated by 107b, and the effective imaging range of the optical image by the optical system 104 is indicated by 107c. The other part is an unused area 107d.
JP 2001-2221961 A

  The technique described in the above-mentioned Japanese Patent Application Laid-Open No. 2001-2221961 and the technique shown in FIGS. 17 to 19 use a D-cut lens to bring the distance between the optical systems closer. The demand for reducing the diameter requires further closer proximity between the optical systems, and further reduction in the diameter of the lens frame that holds these optical systems, and further reduction in the diameter of the entire imaging unit. Further, in the conventional technique as described above, as shown in FIG. 17B and FIG. 18, it cannot be said that the imaging range of the CCD 107 is sufficiently effectively used, and is a useless area that is not used for imaging an image. Has occurred.

  The diameter reduction of the endoscope is not limited to the case where a plurality of objective optical systems are arranged in parallel, but is similarly required in the case of a single objective optical system.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electronic endoscope capable of reducing the diameter by reducing the space through which a light beam passes.

  In order to achieve the above object, an electronic endoscope according to a first invention includes an insertion portion that includes a distal end portion and can be inserted into a body cavity, and one or more lenses provided at the distal end portion. The objective optical system, a solid-state imaging device provided on the base end side of the objective optical system and provided with an imaging surface, and the passing range of the light beam projected toward the imaging surface by the objective optical system Mask means for defining an effective imaging range that can be imaged on the imaging surface, the size of the effective imaging range provided between the most advanced lens of the lenses included in the objective optical system and the solid-state imaging device And a light guide formed according to the above.

  An electronic endoscope according to a second aspect of the present invention includes an insertion portion that includes a distal end portion and can be inserted into a body cavity, and two optical paths that are provided at the distal end portion and are arranged in parallel. A first objective optical system and a second objective optical system configured to include a solid-state image pickup provided with an imaging surface disposed on a base end side of the first objective optical system and the second objective optical system. A first mask that defines a first effective imaging range that can be imaged on the imaging surface by restricting a passage range of a light beam projected toward the imaging surface by the element and the first objective optical system And a second mask unit that defines a second effective imaging range that can be imaged on the imaging surface by regulating a passage range of a light beam projected toward the imaging surface by the second objective optical system and the second objective optical system And a mask means having the first objective optical system A first light guide formed between the most advanced lens of the lens to be rotated and the solid-state image sensor and formed according to the size of the first effective imaging range; and the second objective optical A second light guide that is provided between a state-of-the-art lens included in the system and the solid-state image sensor and is formed in accordance with the size of the second effective imaging range. It is.

  The electronic endoscope according to a third aspect of the invention is the electronic endoscope according to the first aspect of the invention, wherein the light guide path has a cross-sectional shape perpendicular to the optical axis of the objective optical system in the effective imaging range. It is formed according to the size of the effective imaging range so as to have a shape that does not allow passage of at least a part of the luminous flux that can reach the outside.

  The electronic endoscope according to a fourth aspect of the invention is the electronic endoscope according to the second aspect of the invention, wherein the mask means includes a center of a light beam passage range defined by the first mask portion, and the second mask. The center of the passage range of the light beam defined by the part is configured to be close to each other, and the first light guide has a cross-sectional shape perpendicular to the optical axis of the first objective optical system, It is formed according to the size of the first effective imaging range so as to have a shape that does not allow passage of at least part of the luminous flux that can reach the outside of the first effective imaging range, and the second The light guide path is configured such that the shape of the cross section perpendicular to the optical axis of the second objective optical system does not pass at least part of the luminous flux that can reach the outside of the second effective imaging range. It is formed according to the size of the second effective imaging range Te, wherein the first light path and the second light path, in accordance with the first mask part and the second mask part, but that is configured to close to each other.

  An electronic endoscope according to a fifth aspect of the invention is the electronic endoscope according to the third aspect of the invention, wherein the effective imaging range is such that one side is a long side and the other side is a short side shorter than the long side. The shape of the cross section perpendicular to the optical axis of the objective optical system of the light guide path is a substantially oval shape that does not allow a light beam that can reach the outside of the short side of the effective imaging range to pass therethrough. .

  The electronic endoscope according to a sixth aspect of the invention is the electronic endoscope according to the fourth aspect of the invention, wherein the first effective imaging range and the second effective imaging range each have a long side on the other side and the other side on this side. It is a substantially rectangular shape having a short side shorter than the long side, and the cross-sectional shape perpendicular to the optical axis of the first objective optical system of the first light guide is the shape of the first effective imaging range. The shape of the cross section perpendicular to the optical axis of the second objective optical system of the second light guide path is a substantially oval shape that does not allow the light beam that can reach near the outside of the short side to pass. 2 has a substantially oval shape so as not to pass a light beam that can reach the outside of the short side of the effective imaging range.

  An electronic endoscope according to a seventh aspect of the invention is the electronic endoscope according to the first aspect of the invention, wherein the electronic endoscope is disposed rearward on the optical path of the light guide path and is perpendicular to the optical axis of the objective optical system of the light guide path. A flare stop having a light beam passage hole having an area smaller than the area of the cross section is further provided.

  An electronic endoscope according to an eighth invention is the electronic endoscope according to the second invention, wherein the first light guide path of the first light guide path disposed rearward on the optical path of the first light guide path. A first flare stop having a light beam passage hole having an area smaller than the cross-sectional area perpendicular to the optical axis of the objective optical system; and the second light guide disposed on the rear side of the optical path of the second light guide. And a second flare stop having a light beam passage hole having an area smaller than an area of a cross section perpendicular to the optical axis of the second objective optical system in the optical path.

  According to the electronic endoscope of the present invention, the space through which the light beam passes can be reduced and the diameter can be reduced.

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

[Embodiment 1]
FIGS. 1 to 12 show Embodiment 1 of the present invention, FIG. 1 is a perspective view showing an external appearance of an electronic endoscope, and FIG. 2 is an enlarged perspective view of a main portion showing a distal end surface side of a distal end portion of an insertion portion. 3 is a front view showing the configuration of the distal end surface of the distal end portion of the insertion portion, FIG. 4 is a cross-sectional view taken along the line AA showing the portion including the forceps channel and the imaging unit inside the distal end portion of the insertion portion, and FIG. FIG. 6 is a diagram showing the relationship between the imaging range on the CCD and the light beam height, and FIG. 7 is a diagram for showing the shape of the light guide path in the imaging unit. -B sectional view, FIG. 8 is a diagram showing the light beam height in the light guide in comparison with the prior art, FIG. 9 is a CC sectional view for showing the shape of the flare stop, and FIG. 10 is for showing the shape of the D-cut lens. DD sectional drawing of FIG. 11, FIG. 11 is a figure which shows the 1st display example of the imaged image, 12 is a diagram showing a second display example of an image imaged.

  As shown in FIG. 1, an electronic endoscope (appropriately abbreviated as “endoscope”) 1 is provided on an elongated insertion portion 2 that can be inserted into a body cavity, and on the proximal end side of the insertion portion 2. The operation unit 3 and a connector cord (or universal cord) 4 extending from the operation unit 3 are provided.

  The insertion portion 2 includes, in order from the distal end side toward the proximal end side, a distal end portion 5, a bendable bending portion 6, and a long and flexible soft tube portion 7 having flexibility (softness). It is configured.

  The operation unit 3 is provided with a grasping portion 3a for an operator to grasp. Further, a bending operation lever 8 for performing an operation of bending the bending portion 6 is provided on the hand side of the operation portion 3 viewed from the operator of the grip portion 3a. One end of an operation wire (not shown) inserted through the insertion portion 2 is fixed to the bending operation lever 8, and the other end of the operation wire is fixed to the distal end of the bending portion 6. Therefore, when the surgeon operates the bending operation lever 8 and pulls the operation wire, the bending portion 6 is bent up and down. Thus, by operating the bending operation lever 8, the tip 5 can be directed in a desired direction.

  A forceps insertion port 9 for inserting a treatment tool such as a forceps is provided on the distal end side of the grasping portion 3a of the operation portion 3 as viewed from the operator. The treatment instrument inserted from the forceps insertion opening 9 is inserted through a forceps channel 26 (see FIGS. 2, 3, and 4) provided inside the insertion portion 2, and the treatment tool is inserted into the opening portion of the distal end portion 5. It protrudes from the forceps port 27 (see FIGS. 2 and 4). By operating the treatment tool in this state, a treatment or the like for collecting the affected tissue can be performed.

  Further, a connector 12 having a light source connection part 10 and an image processing apparatus connection part 11 is provided at the distal end of the connector cord 4 extended from the operation part 3.

  The light source connection portion 10 provided on the distal end side of the connector 12 includes a light guide connector that connects one end of a light guide (not shown) inserted through the insertion portion 2, the operation portion 3, and the connector cord 4. It is detachably connected to a light source device (not shown). In a state where the light source connection unit 10 and the light source device are connected, the illumination light generated from the light source device is transmitted to the light guide through the light source connection unit 10, and the light guide guides the insertion unit 2. It is transmitted to the tip side.

  An image processing device connection unit 11 provided on the side of the connector 12 is a connection unit for connecting to an image processing device (not shown) such as a video processor. A video signal from a later-described CCD 37 (see FIG. 4) disposed at the distal end portion 5 is transmitted to the image processing device via the image processing device connecting portion 11 and processed, and is connected to the image processing device. Etc. are displayed.

  As shown in FIGS. 2 and 3, the distal end surface 21 of the distal end portion 5 of the insertion portion 2 has an imaging unit 22 for imaging the test site and a tip portion of the illumination optical system 24 that illuminates the test site. And a forceps port 27 serving as an opening on the outlet side of the forceps channel 26 communicating with the forceps insertion port 9 are exposed.

  Next, with reference to FIG. 4, an internal configuration of the distal end portion of the insertion portion will be described.

  The imaging unit 22 of the present embodiment includes two objective optical systems arranged in parallel, and each objective optical system includes one or more lenses. The first objective optical system 33 is designed to have a wide angle of view, for example, and the second objective optical system 34 is designed to have a narrow (larger) view angle, for example. Is. The first objective optical system 33 and the second objective optical system 34 are attached to the lens frame 32 so that their optical axes are parallel to each other.

  The lens frame 32 is further attached to a fixed frame 35, and a cover glass 36 is fixed to the fixed frame 35. A CCD 37, which is a solid-state imaging device, is disposed on the base end side of the cover glass 36, and photoelectric conversion of an optical image by the first objective optical system 33 and an optical image by the second objective optical system 34 is performed. It is supposed to be.

  A protective tube 38 is provided so as to cover the CCD 37, and a distal end portion of the protective tube 38 is externally fitted to the fixed frame 35.

  Such an imaging unit 22 is fixed to the front frame 31 on the outer peripheral side of the lens frame 32 and the fixed frame 35 on the front end side.

  Further, a distal-side forceps base 41 is fixed to the front frame 31, and a hollow and flexible channel tube 42 is inserted and bonded to the outside of the proximal end side of the distal-side forceps base 41. It is fixed with agents.

  Furthermore, a first node ring 43 that forms the forefront of the bending portion 6 is fitted on the proximal end side of the front frame 31. And the outer tube | pipe 44 which is watertight, airtight, and flexible is covered so that the outer peripheral side of this 1st node ring 43 may be covered.

  Next, further details of the imaging unit 22 as described above will be described with reference to FIG.

  The first objective optical system 33 includes a first lens 51, a second lens 52, a third lens 53, and a fourth lens 57a.

  The second objective optical system 34 includes a first lens 54, a second lens 55, and a third lens 57b.

  Of these lenses, the fourth lens 57a in the first objective optical system 33 and the third lens 57b in the second objective optical system 34 are viewed from the optical axis direction as shown in FIG. The lens is configured as a so-called D-cut lens that roughly shortens the shape of the letter “D.” An optical system for dividing the left and right optical systems between the cut plane portions. A partition 58 is provided, and the fourth lens 57a, the third lens 57b, and the partition 58 are integrally joined to form a D-cut lens unit 57.

  The lens frame 32 is formed with a first lens hole 32a formed of a circular hole and a second lens hole 32b formed of a circular hole. The first lens hole 32a is a hole for disposing the first lens 51, the second lens 52, and the third lens 53 in the first objective optical system 33, and the second lens hole 32b is the first lens hole 32b. This is a hole for disposing the first lens 54 and the second lens 55 in the second objective optical system 34.

  A lens locking hole 32c, which is a circular hole having a slightly smaller diameter than the first lens hole 32a, is provided on the proximal end side of the first lens hole 32a, and also on the proximal end side of the second lens hole 32b. A lens locking hole 32d, which is a circular hole having a slightly smaller diameter than the second lens hole 32b, is provided. Since the lens locking hole 32c receives the third lens 53 and the lens locking hole 32d receives the second lens 55, respectively, it is configured as a circular hole as described above.

  Further, a light guide path 32e having a substantially oval shape as shown in FIG. 7 is provided at the base end side of the lens locking hole 32c, and the base end side of the lens locking hole 32d is similarly substantially long. Circular light guides 32f are respectively provided. The light guide path 32e and the light guide path 32f are arranged so as to be close to each other as compared to the conventional example as shown in FIG. 19, and the direction connecting the center axes of each other is substantially oval. It is comprised so that it may become a minor axis direction.

  On the imaging surface 37a of the CCD 37, the range in which an optical image is captured by the first objective optical system 33 is a vertically long effective imaging range 37b that occupies approximately half of the imaging surface as shown in FIG. 5B and FIG. Similarly, the range in which an optical image is captured by the second objective optical system 34 is also a vertically long effective imaging range 37c that occupies approximately half of the imaging surface. The other thin frame portion is the non-use area 37d.

  The shape of the cross section perpendicular to the optical axis of the light guide paths 32e and 32f prevents the light flux entering the effective imaging ranges 37b and 37c having such a shape from being emitted, and is outside the effective imaging ranges 37b and 37c. It is formed in a shape that does not allow an unnecessary luminous flux to pass through. In addition, the process for preventing reflection of light is given to the internal peripheral surface of these light guide paths 32e and 32f.

  The height of the light beam passing through each of the light guide paths 32e and 32f is as shown by the dotted line hatching in FIG. When the light beam height shown in FIG. 7 is compared with the conventional light beam height shown in FIG. 19, as shown in FIG. 8, the light beam heights coincide in the major axis direction of the light guide paths 32e and 32f. It can be seen that the ray height is lower than in the prior art. When the light flux having such a light beam height in the light guide paths 32e and 32f reaches the image pickup surface 37a of the CCD 37, the light beam height becomes as shown by a dotted line in FIG. The light beam heights shown in FIGS. 5B and 6 significantly reduce the light flux outside the effective imaging range compared to the light beam heights shown in FIGS. 17B and 18 in the conventional example. The height of the light beam makes it possible to make effective imaging ranges close to each other, reduce unused areas, and effectively use the imaging surface.

  In FIGS. 5B and 6, the light flux from the first objective optical system 33 toward the effective imaging range 37 c and the light flux from the second objective optical system 34 toward the effective imaging range 37 b are shown. Are prevented from leaking by the optical partition 58 provided in the D-cut lens unit 57 as described above. Further, the central portion of the mask 59 described later also plays a part of the role of separating the light beams of the two objective optical systems 33 and 34.

  Further, the shapes of the effective imaging ranges 37b and 37c as described above are determined by a mask for defining the light beam passage range. That is, a mask 59 serving as a mask means is attached to the base end side surface of the cover glass 36. The mask 59 includes a mask part 59a for determining the shape of the effective imaging range 37b and a mask part 59b for determining the shape of the effective imaging range 37c.

  In addition, a flare stop 56 is provided on the front end side of the D-cut lens unit 57 that is behind the light guide paths 32e and 32f on the optical path so as to cut unnecessary light flux that can reach outside the effective imaging ranges 37b and 37c. It has become. As shown in FIG. 9, the flare stop 56 has a contour having the same shape as the tip-side surface of the D-cut lens unit 57, and a D-shaped hole 56a for allowing the light beam of the first objective optical system 33 to pass therethrough. And a D-shaped hole 56b for allowing the light beam of the second objective optical system 34 to pass therethrough. As shown in FIG. 5A, the D-shaped hole 56a is formed to be smaller than the cross-sectional area of the light guide path 32e, and the D-shaped hole 56b is formed to be smaller than the cross-sectional area of the light guide path 32f. Has been. Since the light guide paths 32e and 32f are formed in a shape that does not allow unnecessary light beams that do not contribute to the effective imaging ranges 37b and 37c to pass therethrough, as described above, processing for preventing internal reflection is performed. However, since some reflected light may still be generated, unnecessary flare can be removed with higher accuracy by using this flare stop 56. Note that the position of the tip side of the D-cut lens unit 57 where the flare stop 56 is disposed is that the light beams of the two objective optical systems 33 and 34 are relatively narrowed, and one light beam becomes the other light beam. The position is almost unaffected.

  Note that various sizes and shapes of the holes of the mask portions 59a and 59b formed in the mask 59 as described above are adopted depending on the design of the objective optical system and the display form of the captured image on the monitor. Of course, and need not be the same.

  A first display example of an image on a display screen 61 of a monitor connected to a video processor (not shown) will be described with reference to FIG. In this display example, an image by one objective optical system is displayed in a larger display area 62, and an image by the other objective optical system is displayed in a slightly smaller display area 63. Such display areas having different sizes can be determined by performing image processing in the video processor and changing the display image size. However, the imaging unit captures images of different sizes. It may be determined optically by configuring. That is, when optically determined, the image displayed by the CCD 37 remains on the display screen 61. That is, the display screen 61 corresponds to the entire imaging area on the CCD 37 as it is, the slightly larger display area 62 corresponds to the effective imaging range by one objective optical system, and the slightly smaller display area 63 corresponds to the other objective optical system. It corresponds to the effective imaging range as it is. At this time, the mask portions 59a and 59b formed on the mask 59 as described above may be formed in shapes corresponding to the display areas 62 and 63 shown in FIG.

  Similarly, FIG. 12 shows a second display example of the image on the display screen 61 of the monitor. The size relationship between the display areas arranged on the left and right is opposite to that in the example shown in FIG. 11, with the left display area 65 being a larger area and the right display area 64 being a smaller area. In addition, an area 66 in which no image is displayed is provided on the small display area 64. By displaying character information or the like in this area 66, for example, information on the subject is displayed. Can be done.

  With this configuration, the diameter of the conventional imaging unit shown in FIG. 17 is φB, whereas the diameter of the imaging unit of the present embodiment shown in FIG. 5 is φA (φA <φB), so that the lens frame Therefore, it is possible to reduce the diameter of the imaging unit, the imaging unit, and the endoscope.

  In the above description, the light guide paths 32e and 32f are substantially oval shapes. However, the present invention is not limited to this, and the light guide paths 32e and 32f may be located outside the effective imaging range on the solid-state imaging device, that is, the light flux passage area defined by the mask. Various shapes can be adopted as long as unnecessary light in the light guide portion is not allowed to pass therethrough. That is, the cross section of the light guide path can be formed in, for example, a rectangular shape, or can be a substantially rectangular shape with four rounded corners. Furthermore, when the effective imaging region has a shape other than a quadrangle, it is of course possible to use a light guide having a cross-sectional shape matched to such a shape. Any shape that does not pass is acceptable.

  In the above description, the light guide path on the tip side of the D-cut lens unit 57 is formed in a substantially oval shape. However, the present invention is not limited to this, and the light guide path in the objective optical system or the objective optical system reaches the CCD. Similarly, any of the light guide paths up to the above can be formed so as to have a cross-sectional shape in which the light ray height differs in one direction and the other direction. That is, it is possible to form an arbitrary portion of the light guide path between the state-of-the-art lens in the objective optical system and the solid-state imaging device according to the size of the effective imaging range.

  According to the first embodiment, since the light guide path is formed in a cross-sectional shape in which the light ray height in the plane perpendicular to the optical axis is different in one direction and the other direction, the volume of the light guide path is reduced. Can do. Since other members and the like can be disposed in the portion where the light guide path is reduced, the diameter of the endoscope can be reduced. In particular, in the present embodiment, since a plurality of objective optical systems are provided and the cross-sectional shape of the light guide is formed so that these objective optical systems can be brought close to each other, the diameter of the imaging unit can be reduced. As a result, the diameter of the endoscope can be reduced.

  Further, since the flare stop is disposed at the position where the light beam is converged, unnecessary light can be removed well.

[Embodiment 2]
FIGS. 13 and 14 show Embodiment 2 of the present invention. FIG. 13 is a front view showing the configuration of the distal end surface of the distal end portion of the insertion portion, and FIG. 14 is a view showing a display example of a captured image. is there. In the second embodiment, parts that are the same as those in the first embodiment are given the same reference numerals and description thereof is omitted, and only differences are mainly described.

  In the second embodiment, three objective optical systems are provided in the imaging unit 22A.

  That is, the imaging unit 22 </ b> A includes a first objective optical system 71, a second objective optical system 72, and a third objective optical system 73, and each of these objective optical systems 71. -73 are arranged in parallel so that the optical axes are parallel to each other. The imaging planes of the objective optical systems 71 to 73 are configured to be on the same plane, and the CCD is arranged so that the plane coincides with the imaging plane of the CCD, which is a solid-state imaging device (not shown). Has been placed.

  When an image captured by such a CCD is displayed on a display screen 75 of a monitor (not shown), three images 76 to 78 corresponding to the objective optical systems 71 to 73 are displayed.

  This means that optical images corresponding to the images 76 to 78 are formed on the imaging surface of the CCD corresponding to the display screen 75 by the objective optical systems 71 to 73, respectively. An optical image is defined by a mask as in the first embodiment.

  And in such a structure, the light guide path in each objective optical system 71-73 or the light guide path from each objective optical system 71-73 to CCD need not reach the outside of the imaging range prescribed | regulated by a mask. In the same manner as described above, the light guide paths are formed so as to prevent the light flux from passing through and are arranged close to each other. Such a configuration can be similarly applied even when four or more objective optical systems are provided in the imaging unit.

  According to the second embodiment, even when three or more objective optical systems are provided in the imaging unit, it is possible to achieve substantially the same effect as the first embodiment described above.

[Embodiment 3]
15 and 16 show Embodiment 3 of the present invention. FIG. 15 is a cross-sectional view along the optical axis showing the configuration of the imaging unit, and FIG. 16 is perpendicular to the optical axis showing the configuration of the imaging unit. It is EE sectional drawing. In the third embodiment, parts that are the same as those in the first and second embodiments are given the same reference numerals, description thereof is omitted, and only differences are mainly described.

  Unlike the first and second embodiments, the imaging unit 22B has a single objective optical system.

  That is, the objective optical system includes the first lens 81, the second lens 82, the third lens 83, the fourth lens 84, the fifth lens 85, and the sixth lens 86. Yes.

  Among these, the first to fifth lenses 81 to 85 are attached to the lens frame 32B.

  The lens frame 32B is further attached to the fixed frame 35B, and the sixth lens 86 is fixed to the fixed frame 35B. On the base end side of the sixth lens 86, a CCD 37B, which is a solid-state image sensor, is arranged to photoelectrically convert an optical image by the objective optical system. A protective tube 38B is provided so as to cover the CCD 37B, and the tip of the protective tube 38 is fitted on the fixed frame 35B.

  More specifically, the lens frame 32B described above has a slightly larger diameter first lens holding portion 32Ba for holding the first lens 81, and second to second lenses for holding the second to fourth lenses 82 to 84. A fourth lens holding portion 32Bb and a fifth lens holding portion 32Bf for holding the fifth lens 85, and a light guide path 32Be between the second to fourth lens holding portions 32Bb and the fifth lens holding portion 32Bf. It has become.

  As shown in FIG. 16, the light guide path 32Be is formed in a substantially oval shape such that the long side direction of the CCD 37B is the major axis direction in accordance with the rectangular CCD 37B having different lengths in the vertical direction and the horizontal direction. Has been. Therefore, the effective imaging range in the CCD 37B is not necessarily determined only by the mask, and in the case of such a single objective optical system, it may be determined by the shape of the CCD 37B itself.

  Although not shown, other members, for example, a channel and an illumination optical system provided in the endoscope 1 may be arranged close to each other in the short diameter direction of the elliptical light guide path 32Be. It becomes possible.

  According to the third embodiment, other members can be disposed closer to the imaging unit, and even when a single objective optical system is provided, substantially the same as the first and second embodiments described above. It is possible to contribute to reducing the diameter of the endoscope.

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

[Appendix]
According to the embodiment of the present invention described in detail above, the following configuration can be obtained.

(1) an optical system arranged in parallel;
A lens constituting the optical system;
A lens frame for holding the lens;
An image sensor that converts light imaged by the optical system into an electrical signal;
In an imaging unit comprising
An electronic endoscope characterized in that the shape of the light guide path through which the light beam of the optical system installed in the lens frame passes is a long hole.

(2) The electronic endoscope according to appendix (1), further comprising a diaphragm provided with a hole smaller than the long hole at a rear side of the light guide path which is a long hole.

  The present invention can be suitably used for an electronic endoscope configured to photoelectrically convert an optical image formed by an objective optical system using an imaging device.

1 is a perspective view showing an external appearance of an electronic endoscope according to Embodiment 1 of the present invention. The principal part expansion perspective view which shows the front end surface side of the insertion part front-end | tip part in the said Embodiment 1. FIG. The front view which shows the structure of the front end surface of the insertion part front-end | tip part in the said Embodiment 1. FIG. FIG. 5 is a cross-sectional view taken along line AA showing a portion including a forceps channel and an imaging unit inside the distal end portion of the insertion portion of the first embodiment. FIG. 2 is a cross-sectional view illustrating a configuration of an imaging unit in Embodiment 1 and a diagram illustrating an imaging range on a CCD. FIG. 3 is a diagram illustrating a relationship between an imaging range on the CCD according to the first embodiment and a light ray height. BB sectional drawing for showing the shape of the light guide in the imaging unit of the above-mentioned Embodiment 1. FIG. The figure which shows the light beam height in the light guide of the said Embodiment 1 compared with the past. CC sectional drawing for showing the shape of the flare stop in the said Embodiment 1. FIG. DD sectional drawing for showing the shape of the D cut lens in the said Embodiment 1. FIG. FIG. 3 is a diagram illustrating a first display example of a captured image in the first embodiment. The figure which shows the 2nd example of a display of the imaged image in the said Embodiment 1. FIG. The front view which shows the structure of the front end surface of the insertion part front-end | tip part in Embodiment 2 of this invention. The figure which shows the example of a display of the imaged image in the said Embodiment 2. FIG. Sectional drawing along the optical axis which shows the structure of the imaging unit in Embodiment 3 of this invention. EE sectional drawing perpendicular | vertical to the optical axis which shows the structure of the imaging unit in the said Embodiment 3. FIG. Sectional drawing which shows the structure of the imaging unit comprised so that a several image may be imaged on one CCD by two objective optical systems conventionally, and the figure which shows the imaging range on CCD. The figure which shows the light ray height and imaging range of the light beam by two objective optical systems on CCD conventionally. FF sectional drawing which shows the light guide path and light ray height in an imaging unit conventionally.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electronic endoscope 2 ... Insertion part 3 ... Operation part 3a ... Gripping part 4 ... Connector cord 5 ... Tip part 6 ... Bending part 7 ... Flexible tube part 8 ... Bending operation lever 9 ... Forceps insertion port 10 ... Light source connection part DESCRIPTION OF SYMBOLS 11 ... Image processing apparatus connection part 12 ... Connector 21 ... Front end surface 22,22A, 22B ... Imaging unit 24 ... Illumination optical system 25 ... Cover lens 26 ... Forceps channel 27 ... Forceps opening 31 ... Front frame 32, 32B ... Lens frame 32a ... 1st lens hole 32b ... 2nd lens hole 32c, 32d ... Lens locking hole 32e, 32f ... Light guide path 32Ba ... 1st lens holding part 32Bb ... 2nd-4th lens holding part 32Be ... Light guide path 32Bf ... Fifth lens holder 33, 34 ... Objective optical system 35, 35B ... Fixed frame 36 ... Cover glass 37, 37B ... CCD
37a ... Imaging surfaces 37b, 37c ... Effective imaging range 37d ... Non-use area 38, 38B ... Protection tube 41 ... Tip side forceps cap 42 ... Channel tube 43 ... First node ring 44 ... Outer tube 51 ... First lens 52 2nd lens 53 ... 3rd lens 54 ... 1st lens 55 ... 2nd lens 56 ... Flare stop 56a, 56b ... D-shaped hole 57 ... D-cut lens unit 57a ... 4th lens (D-cut lens)
57b ... Third lens (D-cut lens)
58 ... Partition 59 ... Mask (mask means)
59a, 59b ... Mask part 61 ... Display screen 62, 63, 64, 65 ... Display area 66 ... Area where image is not displayed 71-73 ... Objective optical system 75 ... Display screen 76-78 ... Image 81-86 ... Lens

Claims (8)

An insertion portion comprising a tip portion and capable of being inserted into a body cavity;
An objective optical system that is provided at the tip and includes one or more lenses;
A solid-state imaging device disposed on the base end side of the objective optical system and provided with an imaging surface;
Mask means for defining an effective imaging range that can be imaged on the imaging surface by regulating a passage range of a light beam projected toward the imaging surface by the objective optical system;
A light guide provided between the most advanced lens of the lenses included in the objective optical system and the solid-state imaging device, and formed according to the size of the effective imaging range;
An electronic endoscope characterized by comprising: An insertion portion comprising a tip portion and capable of being inserted into a body cavity;
A first objective optical system and a second objective optical system which are provided at the tip and form two parallel optical paths, each including one or more lenses;
A solid-state imaging device that is disposed on a proximal end side of the first objective optical system and the second objective optical system and includes an imaging surface;
A first mask portion that defines a first effective imaging range that can be imaged on the imaging surface by regulating a passage range of a light beam projected toward the imaging surface by the first objective optical system; A second mask portion that defines a second effective imaging range that can be imaged on the imaging surface by regulating a passage range of a light beam projected toward the imaging surface by the second objective optical system; Mask means having
A first guide formed between the most advanced lens of the lenses included in the first objective optical system and the solid-state imaging device and formed according to the size of the first effective imaging range. The optical path,
A second guide formed between the most advanced lens of the lenses included in the second objective optical system and the solid-state imaging device and formed according to the size of the second effective imaging range. The optical path,
An electronic endoscope characterized by comprising:   The size of the effective imaging range is such that the shape of the cross section perpendicular to the optical axis of the objective optical system is such that at least a part of the light beam that can reach the outside of the effective imaging range does not pass through the light guide path. The electronic endoscope according to claim 1, wherein the electronic endoscope is formed according to the above. The mask means is configured such that the center of the light beam passage range defined by the first mask portion and the center of the light beam passage range defined by the second mask portion are close to each other. ,
The first light guide path has a cross-sectional shape perpendicular to the optical axis of the first objective optical system such that at least a part of the light beam that can reach the outside of the first effective imaging range does not pass. And is formed according to the size of the first effective imaging range,
The second light guide path has a cross-sectional shape perpendicular to the optical axis of the second objective optical system such that at least part of the light beam that can reach the outside of the second effective imaging range does not pass. And formed according to the size of the second effective imaging range,
The first light guide path and the second light guide path are configured to be close to each other according to the first mask portion and the second mask portion. The electronic endoscope according to claim 2. The effective imaging range is a substantially rectangular shape in which one side is a long side and the other side is a short side shorter than the long side,
The shape of the cross section of the light guide path perpendicular to the optical axis of the objective optical system is substantially oval so as not to pass a light beam that can reach the outside of the short side of the effective imaging range. The electronic endoscope according to claim 3. Each of the first effective imaging range and the second effective imaging range has a substantially rectangular shape in which one side is a long side and the other side is a short side shorter than the long side,
The shape of the cross section of the first light guide path perpendicular to the optical axis of the first objective optical system is substantially long so that a light beam that can reach the outside of the short side of the first effective imaging range does not pass. A circular shape,
The shape of the cross section of the second light guide path perpendicular to the optical axis of the second objective optical system is substantially long so that a light beam that can reach the outside of the short side of the second effective imaging range does not pass. The electronic endoscope according to claim 4, wherein the electronic endoscope is circular.   It further comprises a flare stop having a light beam passage hole having an area smaller than an area of a cross section perpendicular to the optical axis of the objective optical system of the light guide path, which is disposed rearward on the light path of the light guide path. The electronic endoscope according to claim 1. A light beam passage hole having an area smaller than the area of the cross section perpendicular to the optical axis of the first objective optical system of the first light guide path disposed rearward on the optical path of the first light guide path. 1 flare aperture,
A second light-passing hole having an area smaller than the cross-sectional area perpendicular to the optical axis of the second objective optical system of the second light guide path, which is disposed rearward on the optical path of the second light guide path. 2 flare stops,
The electronic endoscope according to claim 2, further comprising:

Images