JP2007007179A - Imaging device for electronic endoscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging device for an electric endoscope where lead wires are not disconnected even when a strong tension is applied to a signal cable. <P>SOLUTION: The imaging device for the electric endoscope comprises: a solid-state imaging element 32; a circuit board 57 for driving the solid-state imaging element 32; a plurality of lead wires connected to the solid-state imaging element 32 or the circuit board 57; the signal cable 50 interpolating a plurality of insulated strings 71; and a frame member 48 for housing the solid-state imaging element. In the device, the strings 71 are fixed while they are pulled by the frame member 48. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electronic endoscope, and relates to an electronic endoscope in which an imaging device is provided at the distal end of an insertion portion.

  In general, an electronic endoscope is configured to have a long and thin insertion portion in which a solid-state imaging device for capturing an endoscopic observation image and a wiring board to which the solid-state imaging device is attached are incorporated in a distal end portion. Has been. The insertion portion of the electronic endoscope is configured from the distal end to a distal end portion, a bending portion, and a flexible tube portion. For example, in the medical field, the insertion part is inserted into a body cavity and the affected part is observed. In order to insert the insertion portion up to the target site and perform observation, the insertion portion has a structure that can be freely bent at the bending portion and the flexible tube portion. In addition, a signal cable is inserted and disposed in the insertion portion, and the tips of a plurality of lead wires extending from the tip of the signal cable are connected and fixed to the wiring board built in the tip by soldering.

  In this electronic endoscope, when the signal cable is pulled in the proximal direction by the bending operation of the insertion portion, tension is applied to each lead wire, so the soldered connection portion of the wiring board and the lead wire or the lead wire is disconnected. In some cases, the space between the wiring board and the tip of the signal cable is filled with an adhesive so that the lead wire extension portion is solidified integrally with the wiring board.

  Further, in order to increase the durability against disconnection of the lead wire or the lead wire connecting portion at the distal end portion, for example, the distal end portion of the electronic endoscope disclosed in Japanese Patent Application Laid-Open No. 2002-65599 has a lead wire in the signal cable. Thread material is inserted and arranged side by side. And the front-end | tip part of the thread material extended from the front-end | tip of a signal cable is set as the structure fixed with a lead wire in the filling part of an adhesive agent. Thereby, since the tension to the signal cable is dispersed in the yarn material, no strong tension acts on the lead wire, and durability against breakage of the lead wire or the lead wire connecting portion at the tip portion can be increased.

  For example, in the endoscope imaging device disclosed in Japanese Patent Application Laid-Open No. 2000-60796, a signal line group for transmitting a video signal obtained by a solid-state imaging device to capture an endoscope observation image is acceptable. The flexible cable is inserted and surrounded by a shield mesh. The signal line group and the shielding mesh line are connected to a member disposed in the vicinity of the solid-state imaging device. Furthermore, the signal line group is configured to be connected and fixed to a member in the vicinity of the solid-state imaging device in a state of being loosened from the shielding mesh line. With this configuration, even if a pulling force acts on the flexible cable, the force is received by the shield netting and is not transmitted to the signal line group, so that the durability against the disconnection of the signal line can be obtained. is there.

Furthermore, in Japanese Patent Laid-Open No. 2000-107124, in an endoscope in which a conductive wire of a signal cable is connected to a substrate on which a solid-state imaging device for capturing an endoscope image is attached, a connecting portion between the conductive wire and the substrate Is known in which an adhesive is applied and an electrically insulating thread material is inserted into the signal cable in the axial direction, and the leading end portion of the thread material is fixed to the substrate.
JP 2002-65599 A JP 2000-60796 A JP 2000-107124 A

  However, in the tip portion of the electronic endoscope having the configuration disclosed in Japanese Patent Laid-Open No. 2002-65599, the tip portion of the thread material extending from the tip of the signal cable is fixed together with the lead wire in the adhesive filling portion. ing. In this configuration, the adhesive surface between the thread material and the adhesive peels off due to moisture absorption of the adhesive, etc., and the tension strength cannot be dispersed by the thread material due to a decrease in the fixing strength of the thread material. There is a possibility of disconnection.

  Moreover, in order to secure the strength against tension, it is necessary to disperse the thread material in the adhesive. However, since it is difficult to disperse uniformly, the strength resistance against tension varies and is stable. It is difficult to secure the signal cable disconnection resistance.

  Further, in an endoscope imaging apparatus having a configuration disclosed in Japanese Patent Laid-Open No. 2000-60796, a shield mesh wire is connected and fixed to a member in the vicinity of a solid-state imaging device for strengthening against tension. However, since the shield mesh is made by weaving a large number of thin wires, when a strong tension is applied to the signal cable, the tension is changed, the mesh spacing changes, and the shield mesh is stretched. It is not suitable as a reinforcing material. In addition, since the shielding mesh wire is arranged outside the cable, it tends to be close to the end of the cable when twisted, and the direction of pulling and the holding direction of the shielding mesh wire are different. A bending force is applied to the position where the network wire is approached, causing the cable to break.

  Furthermore, since the mesh line is connected to a member in the vicinity of the solid-state image sensor, there is a problem that it is difficult to insulate from the signal line group, and the workability of connecting and fixing is complicated and difficult.

  Further, in an endoscope having a configuration disclosed in Japanese Patent Laid-Open No. 2000-107124, a thread material for handling tension applied to a signal cable is fixed to a substrate with an adhesive. However, a normal substrate is based on a relatively thin resin plate and is easily damaged when a force is applied. That is, when the substrate to which the thread material is fixed is damaged, a force is directly applied to the cable, and there is still a possibility of disconnection.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an imaging device for an electronic endoscope in which a lead wire does not break even when a large tension is applied to a signal cable. is there.

  In order to solve the above-described problems, an imaging apparatus for an electronic endoscope according to the present invention is connected to a solid-state image sensor, a circuit board for driving the solid-state image sensor, and the solid-state image sensor or the circuit board. A signal cable in which a plurality of lead wires and a plurality of electrically insulating thread materials are inserted; and a frame member that accommodates the solid-state imaging device, wherein the thread material is pulled by the frame member. It is set as the structure fixed in the state.

  According to the present invention, it is possible to provide an imaging device for an electronic endoscope in which a lead wire does not break even when a large tension is applied to a signal cable.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of an electronic endoscope apparatus. FIG. 2 is a cross-sectional view showing the structure of the imaging apparatus. FIG. 3 is a sectional view showing the structure of the signal cable. FIG. 4 is a cross-sectional view showing a modification of the imaging device according to the embodiment of the present invention. FIG. 5 is a partially enlarged cross-sectional view showing a modification of the image pickup apparatus according to the embodiment of the present invention. FIG. 6 is a cross-sectional view showing a modification of the imaging device according to the embodiment of the present invention. FIG. 7 is a cross-sectional view showing a modification of the imaging apparatus according to the embodiment of the present invention. FIG. 8 is a cross-sectional view showing the configuration of the eccentricity adjusting jig of the imaging apparatus. FIG. 9 is a cross-sectional view for explaining the eccentricity adjusting clearance provided in the imaging apparatus.

  As shown in FIG. 1, an electronic endoscope apparatus 1 according to an embodiment of the present invention includes an electronic endoscope 2, a light source device 16, a video processor disposed on a gantry 21 as a peripheral device of the electronic endoscope 2. 18, a monitor 19, and a keyboard 20 for inputting patient information and the like.

  The electronic endoscope 2 includes an operation unit 3 that is operated by a surgeon, an elongated insertion unit 4 that is formed on the distal end side of the operation unit 3 and is inserted into a body cavity, and a side portion of the operation unit 3. And a universal cord 5 extended from the head.

  The insertion portion 4 has a hard tip portion 6 provided at the tip thereof, a bendable bending portion 7 provided behind the tip portion 6, and a long length provided behind the curve portion 7. And a flexible tube portion 8 having flexibility. The surgeon can bend the bending portion 7 by operating the bending operation lever 9 provided in the operation portion 3.

  The distal end portion 6 includes an observation window 10 for optical observation, a nozzle 11 that sprays a fluid such as water or air on the surface of the observation window 10, an illumination window 12 that emits illumination light, and a treatment instrument. A distal end side opening 13 of the insertion passage is provided. Further, behind the observation window 10, an imaging device 22 to be described later for imaging the body cavity through the observation window 10 is disposed.

  The treatment instrument insertion path is formed by a tube or the like (not shown) disposed in the insertion portion 4, and a distal end side opening 13 thereof has a treatment instrument insertion hole 14 provided in the vicinity of the operation section 3 and a treatment instrument. It communicates with the insertion path.

  A connector 15 is provided at the base end of the universal cord 5, and the connector 15 is connected to the light source device 16. A base (not shown) serving as a connection end of the fluid conduit and a light guide base (not shown) serving as an illumination light supply end project from the base end of the connector 15 so as to protrude from the light source device 16. Removably connected. One end of the connection cable 17 is connected to the electrical contact portion provided on the side surface of the connector 15.

  Illumination light generated in the light source device 16 is transmitted from the universal cord 5 to the distal end portion 6 by a light guide (not shown) inserted into the operation portion 3 and the insertion portion 4. The illumination light is irradiated into the body cavity from the illumination window 12 and illuminates the subject.

  The other end of the connection cable 17 is electrically connected to the video processor 18. The video processor 18 and the imaging device 22 are electrically connected via the connection cable 17, the universal cord 5, the operation unit 3, and a lead wire 75 (described later) inserted through the insertion unit 4.

  The video processor 18 supplies a drive signal for driving the imaging device 22 to the imaging device 22 via the lead wire 75. Upon receiving this drive signal, the imaging device 22 outputs an imaging signal (image signal) to the video processor 18 via the lead wire 75. The video processor 18 performs signal processing on the imaging signal output from the imaging device 22 to generate a video signal. This video signal is output from the video processor 18 to the monitor 19 and displayed as an endoscopic image on the display surface of the monitor 19.

  With the above configuration, the electronic endoscope apparatus 1 displays the subject image captured by the imaging apparatus 22 provided at the distal end portion 6 on the monitor 19 as an endoscopic image.

  The configuration of the imaging device 22 will be described with reference to FIGS.

  The imaging device 22 includes an objective lens unit 31 and an imaging unit 33 having a solid-state imaging device 32 disposed at an image forming position of the objective lens unit 31. As shown in FIG. 2, the imaging device 22 has a substantially cylindrical shape, and an objective lens unit 31 is disposed at the tip. In the imaging device 22, an imaging unit 33 having a circuit board 57 that is a wiring board on which the electronic component 56 is mounted and the solid-state imaging element 32 is disposed at the imaging position of the objective lens unit 31. A signal cable 50 having a cross-sectional structure shown in FIG. 3 is connected and fixed to the base end of the imaging device 22. The subject image formed by the objective lens unit 31 is photoelectrically converted by the solid-state imaging device 32 and output to the video processor 18 through the lead wire 75 inserted into the signal cable 50 as an imaging signal.

  The configuration of the signal cable 50 will be described with reference to FIGS.

  As shown in FIG. 3, a plurality of single wires 52 having a structure in which a core wire, which is formed by twisting a plurality of conductive wires and bundling them, is covered with an insulating coating at the center of the signal cable 50. In addition, an inner conductor formed by twisting and bundling a plurality of conductive strands so as to surround the single wire 52 is covered with an inner insulating coating or an insulating member as an insulating covering, and the outer periphery thereof. A plurality of coaxial wires 51 having a structure in which an outer conductor made of a plurality of conductive strands is twisted and covered with an outer insulating coating that insulates the outer conductor are inserted.

  Further, a plurality of electrically insulating thread materials 71 are inserted into the signal cable 50, and the thread material 71 is disposed so as to fill a space between the single wire 52 and the coaxial wire 51. As the thread material 71, an aramid resin fiber such as a Kevlar (registered trademark) fiber having a low elongation rate is used. A protective tape 72 made of a fluororesin such as Teflon (registered trademark) is wound around the outer periphery of a bundle of lead wires 75 made of the coaxial wire 51 and the single wire 52 in a spiral manner. A shield body 73 is provided on the outer periphery of the protective tape, and a sheath 74 made of a fluororesin such as Teflon (registered trademark) is provided on the outer periphery, here the outermost periphery of the signal cable 50.

  Further, as shown in FIG. 3, in the signal cable 50 according to the present embodiment, the coaxial line 51 and the single line 52 have substantially the same outer diameter. When the coaxial wire 51 and the single wire 52 are compared with the same outer diameter, the single wire 52 has a higher strength against pulling. Therefore, by adopting this configuration, an effect of making it difficult to break the tensile stress can be obtained.

  As shown in FIG. 2, a coaxial line 51, a single line 52, and a thread material 71 extend from the distal end of the signal cable 50 into the imaging device 22. By tightening the tip of the signal cable 50 with the thread 53, each insert of the signal cable 50 is fixed so as not to move forward and backward in the axial direction. Further, the signal cable 50 is covered with a protective tube 54 in order to protect it from abrasion due to rubbing with other built-in objects inside the endoscope 2. The protection tube 54 is fixed so that the signal cable 50 and the protection tube 54 do not move forward and backward by being tightened together with the signal cable 50 by a thread 55 at the tip of the signal cable 50. The signal cable 50 is configured as described above.

  Next, the configuration and assembly method of the imaging unit 33 will be described with reference to FIG.

  As shown in FIG. 2, the solid-state imaging device 32 is a cover glass 46 bonded to a protective glass 45 that covers a light receiving portion of the solid-state imaging device 32 using an optically transparent adhesive such as an ultraviolet curable adhesive. Along with the second flare prevention plate 47, it is fitted and fixed inside a solid-state image sensor frame 48 which is a fixed frame for housing and holding the solid-state image sensor 32. The solid-state imaging device 32 is provided with a plurality of lead pins 49 extending in the proximal direction in two rows. A circuit board 57 on which a plurality of electronic components 56 are mounted is electrically and mechanically connected to one row of the lead pins 49 by soldering or the like. The circuit board 57 is disposed so that the surface of the circuit board 57 is substantially parallel to the central axis direction of the imaging device 22.

  A substantially cylindrical shield frame 58 is fitted and fixed to the outer periphery of the base end portion of the solid-state image sensor frame 48. The base end of the shield frame 58 extends in the base end direction from the circuit board 57, and by surrounding the circuit board 57, noise intrusion into the imaging unit 33 is prevented. The outer peripheral portions of the solid-state imaging element frame 48 and the shield frame 58 are covered with a heat shrinkable tube 59.

  With reference to FIG. 2, a connection configuration between the imaging unit 33 and the signal cable 50 will be described.

  As shown in FIG. 2, the thread material 71 extending from the tip of the signal cable 50 is sandwiched between the solid-state image sensor frame 48 and the shield frame 58 and between the solid-state image sensor frame 48 and the heat shrinkable tube 59. Is done. Further, the thread material 71 is fixed to the outer peripheral portion of the solid-state image sensor frame 48 with an adhesive.

  A plurality of single wires 52 extending from the tip of the signal cable 50 are electrically and mechanically connected to the electronic circuit 57 by solder or the like. A plurality of coaxial wires 51 extending from the tip of the signal cable 50 are electrically and mechanically connected by solder or the like to a row of lead pins 49 to which the circuit board 57 is not connected. An adhesive is applied around the coaxial wire 51, the single wire 52, the lead pin 49, the circuit board 57, and the electronic component 56 to reinforce the connection.

  The coaxial line 51 and the single line 52 are connected with a sufficient length so that no tension is applied to the coaxial line 51 and the single line 52 even when the tension is applied to the yarn material 71.

  The inside of the shield frame 58 of the imaging unit 33 is sealed with a sealing resin 60 such as an epoxy-based adhesive after the signal cable 50 is connected. With the above configuration, the imaging unit 33 and the signal cable 50 are electrically and mechanically connected.

  Hereinafter, a more specific procedure for assembling the imaging unit 33 and the signal cable 50 will be described.

  The imaging unit 33 is fixed to the jig in a state where the shield frame 58 and the heat shrinkable tube 59 are not attached. On the other hand, the signal cable 50 is also fixed on the jig so as to be at a predetermined position with respect to the imaging unit. At this time, the signal cable 50 is inserted through the shield frame 58 in advance. In this state, the coaxial line 51 and the single line 52 extending from the signal cable 50 are connected to predetermined portions of the image pickup unit by soldering or the like with sufficient length. Then, an adhesive is applied around the coaxial line 51, the single line 52, the lead pin 49, the circuit board 57, and the electronic component 56 to reinforce the connection.

  After the imaging unit 33 and the signal cable 50 are connected, the shield frame 58 that has been inserted through the signal cable 50 in advance is fitted into the imaging unit 33 from the proximal direction. At this time, the thread material 71 extending from the signal cable 50 is sandwiched between the shield frame 58 and the solid-state imaging element frame 48 in a state where a certain tension is applied. Thereafter, the inside of the shield frame 58 is sealed by filling a sealing resin 60 such as an epoxy adhesive. Further, the outer periphery of the imaging unit 33 is covered with the heat shrinkable tube 59, whereby the assembly operation of the imaging unit 33 and the signal cable 50 is completed.

  In the above configuration, the substantially cylindrical shield frame 58 is inserted into the signal cable 50 and temporarily disposed before the imaging unit 33 and the signal cable 50 are connected. For this reason, when the shield frame 58 is assembled and fixed to the imaging unit 33, the imaging unit 33 and the signal cable 50 must be removed from the jig once. For example, if the cross-sectional shape of the shield frame 58 is a U-shape, the shield frame 58 can be attached from the outside without removing the imaging unit 33 and the signal cable 50 from the jig, and the work becomes easier.

  Furthermore, the imaging device 22 according to the embodiment of the present invention is configured by fixing the objective lens unit 31 to the solid-state imaging element frame 48 of the imaging unit 33 described above.

  In the electronic endoscope 2 according to the embodiment of the present invention described above, tension is applied in advance to the thread material 71 extending from the distal end of the signal cable 50 in the imaging device 22 disposed at the distal end. In this state, the solid image pickup device frame 48 is fixed. The coaxial line 51 and the single line 52 extending from the tip of the signal cable 50 are connected and fixed to the solid-state imaging device 32 or the circuit board 57 while being loosened from the thread material 71. With this configuration, when a tension is applied to the signal cable 50 by bending the insertion portion 4, the tension is transmitted to the solid-state imaging element frame 48 via the thread material 71. Since the thread material 71 is made of a material having a low elongation rate, the distance between the tip of the signal cable 50 and the solid-state image sensor frame 48 does not change even when a strong tension is applied. For this reason, even if a strong tension acts on the signal cable 50, no tension is applied to the coaxial line 51 and the single line 52, and disconnection of the coaxial line 51 and the single line 52 can be prevented.

  Further, the thread material 71 is sandwiched between the solid-state image sensor frame 48 and the shield frame 58 and bonded to the outer peripheral surface of the solid-state image sensor frame 48. Further, the contact area between the thread material 71 and the adhesive can be widened in the axial direction without increasing the imaging device 22. For this reason, the thread material 71 can be more firmly fixed as compared with the imaging device 22 of the conventional electronic endoscope 2 in which the thread material 71 is fixed only by the adhesive. In addition, the work of fixing the thread material 71 to the solid-state image sensor frame 48 in a state where tension is applied can be easily performed because it can be performed from the outside of the solid-state image sensor frame 48. For this reason, the fixing strength of the thread material 71 and the solid-state imaging device 48 is less likely to vary, and there is no possibility of the signal cable 50 being disconnected.

  Further, as shown in FIG. 3, the thread material 71 is filled in the central portion of the cross section of the signal cable 50, and is unevenly distributed in a part of the cross section of the signal cable 50 when the extending portion of the thread material 71 is twisted. There is nothing to do. Therefore, the thread material 71 extends from the center of the tip of the signal cable 50. For example, when tension is applied to the signal cable 50 in a state where the thread material 71 is biased to a part of the signal cable 50, a bending force is applied to the tip of the signal cable 50. For this reason, since the coaxial line 51 and the single line 52 are bent at the tip of the signal cable 50, it is easy to break. However, if the thread material 71 is configured to extend from the center of the cross section of the signal cable 50 as in the present embodiment, the bending force is applied to the tip of the signal cable 50 when tension is applied to the signal cable 50. Does not occur. Therefore, even when tension is applied to the signal cable 50, it is difficult to apply bending force to the coaxial line 51 and the single line 52, and the signal cable 50 is difficult to be disconnected.

  In the present embodiment, the material of the thread material 71 is an aramid resin, but a thread material such as a glass fiber material or a carbon fiber material may be used. Further, for example, if an electrically insulating material is used for the thread material 71, it is not necessary to consider the electrical insulation between the signal cable 50 and the built-in object of the imaging unit 33. For this reason, the thread material 71 and the member that conducts electricity can be arranged closer to each other, which is advantageous in improving the assembling property and downsizing of the imaging device 22.

  In the present embodiment, the thread material 71 is sandwiched and fixed between the solid-state imaging element frame 48 and the shield frame 58, but this fixed part is a part that can be fixed from the outside of the imaging unit 33. If it is. For example, a notch may be provided at the base end of the solid-state image sensor frame 48, and the thread material 71 may be sandwiched between the notches, or, for example, a protrusion may be provided at the base end of the solid-state image sensor frame 48. The thread material 71 may be sandwiched by bending the portion.

  Further, the fixing method of the thread material 71 to the solid-state image sensor frame 48 is not limited to pinching. For example, as shown in FIG. 4, screw holes 62 are formed on the outer peripheral surface of the solid-state image sensor frame 48, and the thread material 71 may be tightly coupled to a screw 63 fixed to the screw hole 62. At this time, a hole 61 is provided in the solid-state imaging device frame 48 so that the thread material 71 can be linearly passed between the extension portion of the signal cable 50 of the thread material 71 and the screw 63. It is done. In addition, by using an adhesive together with the thread material 71, the fixing strength between the thread material 71 and the solid-state imaging element frame 48 can be further increased.

  Further, for example, as shown in FIG. 5, the thread material 71 tightly coupled to the screw 63 may be fastened to the solid-state imaging element frame 48 using the head of the screw 63. According to this configuration, the fixing strength between the thread material 71 and the solid-state imaging element frame 48 can be increased.

  Furthermore, as shown in FIG. 6, the screw hole 92 is formed in the base end surface of the solid-state imaging device frame 48, and the screw 91 is fastened to the screw hole 92 in a state where the thread material 71 is fastened to the screw 91. Also good. According to this configuration, it is possible to apply tension to the thread material 71 by tightening the screw 91, so that it is not necessary to fix the thread material 71 to the solid-state image sensor frame 48 while applying tension as in the above-described configuration. Become.

  In the modification of the above-described embodiment, a screw member is used as a member for fixing the thread material 71. However, for example, the thread material 71 may be fixed to a knock pin press-fitted into the solid-state imaging element frame 48. Any member may be used as long as a member capable of binding the thread material 71 to the element frame 48 is disposed.

  Furthermore, in this embodiment, the thread material 71 is fixed to the solid-state imaging element frame 48. However, the same effect can be obtained even if the thread material 71 is fixed to the shield frame 58.

  In the present embodiment, the thread material 71 is fixed at one place on the outer periphery of the solid-state image sensor frame 48. However, the thread material 71 has a plurality of intervals that equally divide the outer periphery of the solid-state image sensor frame 48. It may be fixed in place. For example, as shown in FIG. 7, the thread material 71 is distributed to a plurality of locations such as two directions or four directions according to the bending direction of the bending portion 7 and fixed to the solid-state imaging device frame 48. According to this configuration, the positional relationship between the solid-state image sensor frame 48 and the signal cable 50 can be more firmly fixed, and disconnection of the coaxial line 51 and the single line 52 can be prevented more reliably. Further, by making the fixing direction of the thread material 71 substantially coincide with the bending direction of the bending portion 7, the bending resistance with respect to the bending direction is improved, and further, the effect of preventing disconnection is obtained.

  Below, with reference to FIG.2, FIG8 and FIG.9, the assembly adjustment method of the imaging device 22 in the endoscope 2 of this Embodiment is supplementarily demonstrated.

  First, with reference to FIG. 2, a method of adjusting the field angle of the objective lens unit 31 will be described.

  The objective lens frame 34 serving as an exterior member of the objective lens unit 31 has a substantially cylindrical shape, and has circular openings at the distal end and the proximal end, respectively. Each opening part of the front-end | tip and a base end is connected by the internal diameter part smaller than the internal diameter of each opening part.

  A first lens 35, a first flare prevention plate 36, a transparent parallel plate 37, and an angle-of-view adjustment plate 38 are disposed in order from the tip at the opening at the tip of the objective lens frame 34. In addition, a second lens 39, a lens interval holding frame 40, an aperture stop plate 41, and an infrared cut filter 42 are disposed in order from the distal end of the opening at the base end of the objective lens frame 34. The objective lens unit 31 is configured as described above.

  The first lens 35 is a plano-concave lens, and hereinafter, this concave surface is defined as a first lens surface 43. The transparent parallel flat plate 37 is UV cut coated on both sides. The angle-of-view adjusting plate 38 and the first flare prevention plate 36 are formed to have the same outer diameter, the same inner diameter, and the same thickness (30 μm). The 1st flare prevention board 36 has a role for preventing the flare which becomes a diagnostic trouble. The second lens 39 is a biconvex lens, and hereinafter, the convex surface on the tip side is defined as a second lens surface 44. The angle-of-view adjusting plate 38 maintains a lens interval between the first lens surface 43 and the second lens surface 44, and has a role of a spacer for adjusting the interval.

  The respective members arranged inside the objective lens unit 31 are fixed inside the opening of the objective lens frame 34 by applying an adhesive to the outer peripheral surfaces of the first lens 35 and the infrared cut filter 42. ing.

  In general, an endoscope employs an optical system in which the angle of view of the endoscopic image is wide in order to improve the observability. However, in recent years, further widening of the endoscopic image is required. ing. For example, when assembling an ultra-wide-angle objective lens unit 31 with an angle of view exceeding 140 °, considering the processing accuracy of each member constituting the objective lens unit 31, the angle of view of the endoscopic image is simply assembled. May not be 140 ° or more, or the angle of view may be 180 ° or more and vignetting may occur in the endoscopic image. Furthermore, in recent years, there is a tendency to reduce the outer diameter of the distal end of the endoscope in order to improve the insertability and ease the patient's pain. For this reason, the solid-state imaging device 32 and the objective lens unit 31 are being downsized. As the objective lens unit 31 becomes smaller, the influence of the dimensional accuracy of each member on the angle of view increases, so that the angle of view of the endoscopic image tends to be less than 140 ° or 180 ° or more.

  Therefore, in the electronic endoscope 2 according to the present embodiment, when the objective lens unit 31 is assembled, it is necessary to adjust the angle of view of the objective lens unit 31 to be 140 ° or more and less than 180 °. Since the change in the distance L between the first lens surface 43 and the second lens surface 44 has the greatest influence on the angle of view, in this embodiment, the distance L between the first lens surface 43 and the second lens surface 44 is adjusted. As a result, the angle of view of the objective lens unit 31 is adjusted. For adjusting the distance L, an angle-of-view adjusting plate 38 is used. The angle of view adjustment plate 38 can be selectively inserted with a plurality of types of thicknesses to adjust the distance L. However, in this embodiment, it is not necessary to prepare a plurality of types of angle of view adjustment plates. In addition, one type of angle of view adjusting plate is used. That is, the distance L is adjusted by changing the number of inserted angle-of-view adjustment plates 38.

  The angle of view of the objective lens unit 31 becomes a wide angle when the number of the angle-of-view adjusting plates 38 is increased and the distance L is increased, and conversely, the angle of view is narrowed when the number of the angle-of-view adjusting plates 38 is decreased and the distance L is reduced. In general, as the angle of view of the objective lens becomes wider, the amount of change in the angle of view with respect to the change in the distance between the lens surfaces increases. For this reason, in an ultra-wide-angle optical system with an angle of view exceeding 140 °, the angle of view is 180 when the thickness accuracy of the angle-of-view adjusting plate 38, the first lens 35 floats, or the focus is out of focus. There is a concern that vignetting may occur in the endoscopic image and the desired observation performance may be degraded. For this reason, when the angle of view of the super-wide-angle objective lens unit 31 is adjusted by using one type of angle of view adjustment plate 38, the thickness of the angle of view adjustment plate 38 to be used is as thin as possible and is highly accurate. It is desirable to use those.

  In adjusting the angle of view, first, the lens group is fixed to the opening hole at the base end of the objective lens frame 34. Then, after inserting and temporarily fixing the angle-of-view adjusting plate 38, the transparent parallel plate 37, the first flare prevention plate 36, and the first lens 35 into the opening hole at the tip of the objective lens frame 34, the angle of view of the objective lens unit 31 is changed. taking measurement. At this time, if the angle of view of the objective lens unit 31 is less than 140 °, the angle of view adjustment plate 38 is additionally inserted so that the angle of view of the objective lens unit 31 is 140 ° or more and less than 180 °. Make adjustments. Further, when the angle of view of the objective lens unit 31 is 180 ° or more and vignetting has occurred in the endoscopic image, the number of view angle adjusting plates 38 is reduced, and the angle of view of the objective lens unit 31 is 140 ° or more. The adjustment is made so that the angle is less than 180 °. The angle of view of the endoscope can be adjusted by the above means.

  As described above, if the angle of view of the objective lens unit 31 is less than 140 ° or 180 ° or more, it is necessary to insert / remove the angle-of-view adjusting plate 38. Therefore, the first view angle is obtained until a predetermined angle of view is obtained. The lens 35 is preferably temporarily fixed to the objective lens frame 34. Temporary fixing is a method in which there is no lens floating, for example, the adhesive is spotted at three positions between the first lens 35 and the objective lens frame 34. Further, as a means for replacing the temporary fixing with the adhesive, a jig for fixing the first lens 35 to the objective lens frame 34 by pressing from the outside may be used. If this jig is used, the lens can be removed immediately even if the angle of view needs to be readjusted. If the angle of view of the objective lens unit 31 falls within a predetermined value by changing the number of view angle adjusting plates 38, the first lens 35 is permanently fixed to the objective lens frame 34 using an adhesive.

  By the above method, the angle of view of the objective lens unit 31 of the electronic endoscope 2 of the present embodiment is adjusted.

  Next, a method for adjusting the optical axis of the imaging device 22 in the endoscope 2 according to the present embodiment will be described with reference to FIGS.

  As shown in FIG. 2, the imaging device 22 has an optical axis X of the objective lens unit 31 (hereinafter, referred to as an objective optical axis X) and a solid-state imaging element 32 due to the influence of the dimensional error of the constituent members and the gap of the fitting. It has an eccentricity with respect to the light receiving portion central axis Z (hereinafter referred to as the light receiving portion central axis Z). In general, when the amount of eccentricity is large, an image defect such as one-sided blur occurs in an endoscopic image. However, in the case of the ultra-wide-angle imaging device 22 according to the present embodiment, there is no allowance for the amount of eccentricity with respect to vignetting compared to a general optical system, and even when the amount of eccentricity is small, vignetting is observed in the endoscope image. Will occur.

  As a simple adjustment method of eccentricity, the objective lens unit 31 and the imaging unit 33 are relatively rotated at the fitting portion, and fixed at a position where the objective optical axis X and the light receiving portion central axis Z are closest to each other, There is a method of reducing the amount of eccentricity. However, since the eccentricity cannot be reduced below a certain amount by the above method, the super wide-angle imaging device 22 according to the present embodiment may still cause vignetting in the endoscopic image. Therefore, in the imaging device 22 according to the present embodiment, the eccentricity can be adjusted by the method described below, and an endoscopic image without vignetting is realized.

  With reference to FIG. 8, a method for adjusting the eccentricity when assembling the imaging device 22 will be described.

  The base member 83 of the eccentricity adjusting jig shown in FIG. 8 is composed of a horizontal part having two substantially parallel planes and a vertical part having a vertical surface extending substantially vertically upward from one end of the horizontal part. It has an L-shaped cross-sectional shape. In addition, a concave portion having an abutting portion 85, which is a plane for abutting an objective lens unit holding member 81 to be described later, is provided on a plane inside the vertical portion of the base member 83.

  The objective lens unit holding member 81 has a substantially cylindrical shape, and a through hole is provided in the axial direction. The objective lens unit 31 is inserted and fixed in this through hole. The objective lens holding member 81 is fitted at the base end thereof to a fitting portion A provided on the objective lens unit holding member presser 82.

  By pressing the objective lens holding member holding member 82 into the screw hole provided on the vertical surface of the base member 83 in the tip direction using the holding screw 84, the tip surface of the objective lens unit holding member 81 is fixed to the base member 83. Is abutted and fixed to the abutting portion 85.

  On the other hand, a leveling member 87 for fixing an imaging unit holding member 86 (described later) substantially horizontally is fixed to the upper surface of the horizontal portion of the base member 83 by fixing screws 88. A through hole is provided in the imaging unit holding member 86 in a substantially horizontal direction, and the imaging unit 33 is inserted and fixed in the through hole.

Here, since the objective optical axis X of the objective lens unit 31 and the center axis Z of the light receiving section of the imaging unit 33 are substantially coaxial and parallel on the eccentricity adjusting jig, the leveling member 87 and the base member 83 are arranged. The fixing screw 88 is fixed to change the inclination of the imaging unit holding member 86, and the objective optical axis X and the light receiving unit central axis Z are parallelized.

  An eccentricity adjustment clearance 90 as shown in FIG. 9 is provided between the outer diameter of the proximal end portion of the objective lens unit 31 and the hole diameter of the distal end portion of the imaging unit 33.

  When the objective optical axis X of the objective lens unit 31 and the center axis Z of the light receiving unit 32 of the solid-state imaging device 32 are decentered and vignetting occurs in the endoscopic image, the fastening of the holding screw 84 is loosened, and the objective By moving the objective optical axis X by rotating the lens unit holding member 81, the position is adjusted to a position where vignetting does not occur in the endoscopic image or where the amount of vignetting is the smallest. If vignetting occurs only by adjusting the rotation, the knob portion 89 of the objective lens unit holding member holder 82 assembled to the objective lens unit holding member 81 is finely shifted parallel to the abutting portion 85. Thus, the objective optical axis X of the objective lens unit 31 and the light receiving unit central axis Z of the solid-state imaging device 32 are adjusted to a relative position where no vignetting occurs on the endoscopic image. On the eccentricity adjusting jig, the positions of the objective lens unit 31 and the imaging unit 33 are adjusted so that a predetermined endoscopic image can be obtained, and then both are fixed with an adhesive.

  With the above method, the optical axis of the imaging device 22 in the electronic endoscope 2 of the present embodiment is adjusted.

  In order to adjust the imaging device 22 so that vignetting does not occur in the endoscopic image, the objective optical axis X of the objective lens unit 31 and the center of the light receiving unit of the solid-state imaging device 32 are arranged on the eccentricity adjusting jig. It is only necessary that the axis Z can move relatively. Therefore, the member for adjusting the movement is not limited to the objective lens unit holding member 81 that holds the objective lens unit 31, but may be the imaging unit holding member 86 that holds the imaging unit 33. Further, the objective lens unit holding member 81 may be rotationally adjusted, and the imaging unit holding member 86 may be configured to be capable of fine movement shift adjustment, or the rotation adjustment member and the fine movement shift adjustment member may be reversed.

  Furthermore, the adjustment of the imaging device 22 to prevent vignetting in the endoscopic image can also be adjusted by shifting the position of the first lens 35. In this case, the objective lens unit 31 excluding the first lens 35 and the imaging unit 33 are combined. Thereafter, the first lens 35 is fixed at a position where no vignetting occurs in the endoscopic image. In this case, an adjustment clearance is provided between the objective lens 35 and the objective lens frame 34.

  The electronic endoscope 2 according to the embodiment of the present invention described above has the following effects.

  When a tension is applied to the signal cable 50 due to the bending of the insertion portion 4, this tension is inserted only in the signal cable 50 and applied only to the thread material 71 fixed to the solid-state imaging element frame 48. Therefore, no tension is applied to the lead wire 75 inserted into the signal cable 50. Therefore, the lead wire 75 or the connecting portion of the lead wire 75 is not broken.

  Further, since the thread material 71 is sandwiched between the solid-state imaging element frame 48 and the shield frame 58 and is adhered to the outer peripheral surface of the solid-state imaging element frame 48, the fixing and the double fixing can be performed firmly. It is possible to fix the solid-state image sensor frame 48 and the thread material 71. In particular, the holding of the thread material 71 between the solid-state imaging element frame 48 and the shield frame 58 is not affected by moisture absorption as in the case of an adhesive, and thus can be securely held.

  Furthermore, since the fixing work of the thread material 71 can be easily performed from the outside of the imaging device 22, variations in the fixing strength hardly occur. Therefore, it is possible to stably maintain the durability against the tension of the signal cable 50.

1 is an overall configuration diagram of an electronic endoscope apparatus according to an embodiment of the present invention. It is sectional drawing which shows the structure of the imaging device of the electronic endoscope of embodiment of this invention. It is sectional drawing which shows the structure of the signal cable of the electronic endoscope of embodiment of this invention. It is sectional drawing which shows the modification of the imaging device of the electronic endoscope of embodiment of this invention. It is a partial expanded sectional view which shows the modification of the imaging device of the electronic endoscope of embodiment of this invention. It is sectional drawing which shows the modification of the imaging device of the electronic endoscope of embodiment of this invention. It is sectional drawing which shows the modification of the imaging device of the electronic endoscope of embodiment of this invention. It is sectional drawing which shows the structure of the jig for eccentric adjustment of the imaging device of the electronic endoscope of embodiment of this invention. It is sectional drawing explaining the clearance for eccentric adjustment provided in the imaging device of the electronic endoscope of embodiment of this invention.

Explanation of symbols

  22 imaging device, 31 objective lens unit, 32 solid-state imaging device, 33 imaging unit, 34 objective lens frame, 35 first lens, 36 first flare prevention plate, 37 transparent parallel plate, 38 angle of view adjustment plate, 39 second lens , 40 Lens spacing plate, 41 Brightness diaphragm plate, 42 Infrared cut filter, 43 First lens surface, 44 Second lens surface, 45 Protective glass, 46 Cover glass, 47 Second flare prevention plate, 48 Solid-state imaging device Frame, 49 Lead pin, 50 Signal cable, 51 Coaxial wire, 52 Single wire, 53 Yarn, 54 Protection tube, 55 Yarn, 56 Electronic component, 57 Circuit board, 58 Shield frame, 59 Heat shrinkable tube, 60 Sealing resin

Claims (4)

A solid-state image sensor;
A circuit board for driving the solid-state imaging device;
A plurality of lead wires connected to the solid-state imaging device or the circuit board, and a signal cable in which a plurality of electrically insulating thread materials are inserted;
A frame member that houses the solid-state imaging device;
An imaging apparatus for an electronic endoscope, wherein the thread material is fixed in a state of being pulled by the frame member.   The imaging device for an electronic endoscope according to claim 1, wherein the thread material is clamped and fixed to the fixed frame.   The imaging device for an electronic endoscope according to claim 1, wherein the thread material is fastened and fixed to the fixing frame. The imaging device for an electronic endoscope according to claim 1, wherein the thread material is made of an aramid resin material, a glass fiber material, or a carbon fiber material.

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