JP2020108790A - Endoscope - Google Patents

Abstract

To provide an endoscope in which the diameter of an insertion part can be reduced.SOLUTION: An imaging device 20 of an endoscope 2 includes an imaging lens 21, a prism 23 on which an imaging light through the imaging lens 21 is incident, an image sensor 27 attached to an emission surface 23c of the prism 23, a circuit board 29 connected to the image sensor 27, and an electronic part 31 mounted on the circuit board 29. The electronic part 31 is mounted at a position closer to a base end side of the endoscope 2 than a reflection surface 23b of the prism 23 where it overlaps with a shadow of the prism 23 projected on a surface orthogonal to a longitudinal direction of an insertion part 6 of the endoscope 2.SELECTED DRAWING: Figure 3

Description

The present invention relates to an endoscope.

A solid-state image sensor that photoelectrically converts light from the imaged region is provided at the tip of the insertion part of the endoscope. While the insertion portion of the endoscope is required to have a small diameter, there is a limit to reducing the area of the light receiving surface of the solid-state imaging device. This is because it becomes difficult to obtain a high quality image as the area of the light receiving surface becomes smaller. In order to solve this problem, an endoscope including an image pickup unit having a structure in which light from an image pickup region is refracted at right angles by a prism and is incident on a solid-state image pickup element has been considered. As an example thereof, as shown in FIG. 9, a prism 105 and a flexible circuit board 107 are arranged behind a lens barrel 103 holding a taking lens 101, and a solid-state image sensor 109 and a transmission cable are arranged via the flexible circuit board 107. There is known an endoscope imaging unit in which an electronic component 113 such as a capacitor is mounted on the flexible circuit board 107 while electrically connecting the imaging unit 111 and the flexible circuit board 107 (see Patent Document 1).

International Publication No. 2011/092901

However, in the endoscope image pickup unit described in Patent Document 1 shown in FIG. 9, the electronic component 113 is protruded from the solid-state image pickup element 109 by a distance d in a direction orthogonal to the optical axis O of the taking lens 101. Therefore, the electronic component 113 increases the diameter of the imaging unit by at least the distance d. That is, the reduction in diameter of the insertion portion of the endoscope is hindered.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an endoscope in which the diameter of the insertion portion can be reduced.

The endoscope of one embodiment of the present invention is
Shooting lens,
A prism on which the photographing light is incident through the photographing lens,
A solid-state image sensor attached to the exit surface of the prism,
A circuit board connected to the solid-state imaging device,
An electronic component mounted on the circuit board,
A transmission cable electrically connected to the circuit board and extending to the proximal end side of the insertion portion,
An endoscope having:
The transmission cable includes a coaxial cable in which the periphery of a central conductor electrically connected to the circuit board is shielded by a shield conductor,
The electronic component is mounted on the base end side of the endoscope with respect to the reflecting surface of the prism, at a position overlapping with the shadow of the prism projected on a plane orthogonal to the longitudinal direction of the insertion portion of the endoscope. Moreover, it is located on the opposite side of the optical axis of the taking lens from the solid-state image pickup device side.

According to the present invention, it is possible to provide an endoscope in which the diameter of the insertion portion can be reduced.

1 is an external view of an endoscope system for explaining an embodiment of the present invention. It is a figure which shows the 1st example of a structure of the imaging device mounted in the front-end|tip part of the insertion part of an endoscope. It is the sectional view on the AA line shown in FIG. It is a figure which shows the 2nd example of a structure of the imaging device mounted in the front-end|tip part of the insertion part of an endoscope. It is the BB sectional view shown in FIG. It is a figure which shows the 3rd example of a structure of the imaging device mounted in the front-end|tip part of the insertion part of an endoscope. It is a top view of the imaging device shown in FIG. It is sectional drawing which shows another structural example of an imaging device. It is sectional drawing of the conventional imaging device.

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

FIG. 1 shows an example of an endoscope system for explaining an embodiment of the present invention.

The endoscope system 1 includes an endoscope 2, a light source unit 3, and a processor unit 4. The endoscope 2 has an insertion section 6 to be inserted into a subject, an operation section 7 connected to the insertion section 6, and a universal cord 8 extending from the operation section 7. The tip end side and the universal cord 8 are provided on the base end side. The insertion portion 6 is composed of a distal end portion 10, a bending portion 11 connected to the distal end portion 10, and a flexible portion 12 connecting the bending portion 11 and the operation portion 7, and the distal end portion 10 has a longitudinal axis of the insertion portion 6. And the flexible portion 12 is provided on the proximal end side of the longitudinal axis. The distal end side of the insertion section 6 in the longitudinal axis is synonymous with the distal end side of the endoscope 2, and the proximal end side of the insertion section 6 in the longitudinal axis is synonymous with the proximal end side of the endoscope 2.

The distal end portion 10 is provided with an illumination optical system that emits illumination light for illuminating the observation site, an imaging device and an imaging optical system that image the observation site, and the like. The bending portion 11 is configured to be bendable in a direction orthogonal to the longitudinal axis of the insertion portion 6, and the bending operation of the bending portion 11 is operated by the operation unit 7. Further, the flexible portion 12 is relatively flexible so that it can be deformed according to the shape of the insertion path of the insertion portion 6.

The operation unit 7 is provided with a button for operating the imaging operation of the imaging device of the distal end portion 10, a knob for operating the bending operation of the bending portion 11, and the like. Further, the operation section 7 is provided with an introduction port 13 into which a treatment instrument such as an electric scalpel is introduced. Inside the insertion section 6, the treatment instrument is inserted from the introduction port 13 to the distal end portion 10. A treatment instrument channel 14 is provided.

A connector 9 is provided at the end of the universal cord 8, and the endoscope 2 includes a light source unit 3 that generates illumination light emitted from the illumination optical system of the tip portion 10 via the connector 9 and the tip portion 10. It is connected to a processor unit 4 which processes a video signal acquired by the imaging device. The processor unit 4 processes the input video signal to generate video data of the observation site, displays the generated video data on the monitor 5, and records the video data.

A light guide and an electric wire group are housed inside the insertion portion 6, the operation portion 7, and the universal cord 8. The illumination light generated by the light source unit 3 is guided to the illumination optical system of the tip portion 10 via the light guide, and signals and electric power are transmitted between the image pickup device of the tip portion 10 and the processor unit 4 through the wire group. Transmitted.

(First example of imaging device)
FIG. 2 shows a first example of the configuration of the imaging device mounted on the distal end portion 10 of the insertion portion 6. FIG. 3 is a cross-sectional view taken along the line AA shown in FIG. The imaging device 20A shown in FIGS. 2 and 3 includes a taking lens 21, a prism 23, a metal holding member 25 for holding the taking lens 21 and the prism 23, and an image sensor attached to the exit surface 23c of the prism 23. 27, a circuit board 29 connected to the image sensor 27, a capacitor 31 which is one of electronic components mounted on the circuit board 29, and a plurality of (three in this example) transmission cables 51.

The prism 23 has an entrance surface 23a on which the imaging light from the imaged area from the imaging lens 21 enters, and a reflecting surface 23b that refracts a light beam along the optical axis O shown in FIG. , And a rectangular prism 23A having an exit surface 23c, and a bonding member 23B that is joined to the reflective surface 23b of the rectangular prism 23A to protect the reflective surface 23b. The prism 23 is formed in a substantially cubic shape by integrally forming the rectangular prism 23A and the bonding member 23B. Of the five surfaces forming the bonding member 23B, the heat transfer film 35 is provided on each of the base end surface of the insertion portion 6 and the surface of the right-angle prism 23A that faces the emission surface 23c. There is. The heat transfer film 35 is a metal thin film having conductivity, and is formed by metal vapor deposition.

The holding member 25 includes a lens holding body 41, a housing portion 43, and a light shielding member 45, which are all made of metal having conductivity. The lens holder 41 holds the taking lens 21. The housing portion 43 holds the lens holding body 41 and the cover glass 46. The cover glass 46 is integrated with the prism 23 by being attached to the incident surface 23a of the right-angle prism 23A with an optical adhesive. Therefore, the prism 23 is held by the housing portion 43 via the cover glass 46. When the prism 23 is held by the housing portion 43, the tip end side of the insertion portion 6 of the heat transfer film 35 provided on the bonding member 23B of the prism 23 comes into contact with the housing portion 43. Therefore, the heat transfer film 35 and the holding member 25 are electrically and electrically connected.

A light blocking member 45 is provided around a part of the insertion portion 6 of the housing portion 43 on the proximal end side and around the upper portion and both side portions of the prism 23. The light blocking member 45 is arranged so as to be separated from the prism 23, but the space between the light blocking member 45 and the prism 23 is filled with a high thermal conductive resin 47 containing a filler. Further, the thermal contact between the heat transfer film 35 and the housing portion 43 may be measured by performing thermal welding or soldering instead of filling the high thermal conductive resin 47.

The image sensor 27 is a solid-state image sensor such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor. The image receiving surface of the image sensor 27 faces the emitting surface 23c of the rectangular prism 23A and is arranged in parallel with the longitudinal direction of the insertion portion 6.

The circuit board 29 is a so-called flexible circuit board having flexibility. The circuit board 29 has a substantially H shape when unfolded, and has a structure in which two connecting portions 29a and 29b are folded around a joint portion 29c. The image sensor 27 is mounted on one connecting portion 29a of the circuit board 29, and the capacitor 31 is mounted on the other connecting portion 29b.

The capacitor 31 mounted on the connection portion 29b of the circuit board 29 is provided on the base end side of the insertion portion 6 with respect to the prism 23 and at a position overlapping the shadow of the prism 23 projected on a plane orthogonal to the longitudinal direction of the insertion portion 6. Has been. Further, in this example, as shown in FIGS. 2 and 3, the capacitor 31 is arranged in contact with the heat transfer film 35 provided on the surface of the bonding member 23B of the prism 23. Further, the capacitor 31 is installed such that its longitudinal direction coincides with the longitudinal direction of the insertion portion 6, and the negative electrode 34a is arranged closer to the prism 23 side than the positive electrode 34b. Therefore, the negative electrode 34 a of the capacitor 31 contacts the heat transfer film 35.

The transmission cable 51 is a composite cable that extends toward the proximal end side of the insertion portion 6, and is a coaxial cable that includes a center conductor 51a and a braided wire shield conductor 51b that is provided around the center conductor 51a via an insulating layer. including. The center conductor 51a is electrically connected to the connection portion 29a or the connection portion 29b of the circuit board 29. The shield conductor 51b is connected to the negative electrode 34a of the capacitor 31 that is in contact with the heat transfer film 35. In this example, the connection position between the shield conductor 51b and the negative electrode 34a of the capacitor 31 is closer to the tip end side of the insertion portion 6 than the connection position between the central conductor 51a and the connection portions 29a and 29b of the circuit board 29. Therefore, the shield conductor 51b is in tension in the extending direction of the transmission cable 51, while the center conductor 51a is connected in the same direction with a sufficient length. As described above, since the center conductor 51a is connected to the circuit board 29 in a flexed state, the center conductor 51a and the circuit board 29 are not affected by bending stress generated when the endoscope 2 is angled. Peeling is less likely to occur.

According to the configuration of the first example described above, the condenser 31 is located on the base end side of the insertion portion 6 with respect to the prism 23 and at the position overlapping the shadow of the prism 23 projected on the plane orthogonal to the longitudinal direction of the insertion portion 6. It is provided. That is, since the condenser 31 does not protrude from the shadow in the direction orthogonal to the longitudinal direction of the insertion portion 6 (direction of the optical axis O shown in FIG. 3), the imaging device 20A can be downsized and the endoscope 2 The diameter of the insertion part 6 can be reduced.

Further, since the capacitor 31 is arranged in contact with the heat transfer film 35 provided on the surface of the bonding member 23B of the prism 23, the Joule heat generated in the capacitor 31 is conducted to the heat transfer film 35. Further, since the heat transfer film 35 is in contact with the holding member 25, the heat conducted to the heat transfer film 35 is also conducted to the holding member 25, and the heat conducted to the holding member 25 is radiated from the tip of the imaging device 20A. It Since the heat transfer film 35 is in contact with the capacitor 31 and the heat transfer film 35 is in contact with the holding member 25 as described above, the heat dissipation path of the Joule heat generated in the capacitor 31 can be strengthened. Further, since the shield conductor 51b of the transmission cable 51 is connected to the negative electrode 34a of the capacitor 31, the Joule heat generated in the capacitor 31 is also conducted to the shield conductor 51b. Therefore, the heat dissipation path of the Joule heat generated in the capacitor 31 can be further strengthened. As a result, it is possible to suppress the overheating of the capacitor 31 and prevent the deterioration of the quality of the image pickup signal due to the influence of heat.

The position where the capacitor 31 and the heat transfer film 35 contact each other is the negative electrode 34a, and the shield conductor 51b of the transmission cable 51 is also connected to the negative electrode 34a. Therefore, the negative electrode 34a of the capacitor 31 is electrically connected to the holding member 25 through the heat transfer film 35 and also electrically connected to the shield conductor 51b, so that a large ground area can be secured and the ground function can be enhanced. ..

The connection position between the negative electrode 34a of the capacitor 31 and the shield conductor 51b is closer to the tip side of the insertion portion 6 than the position where the central conductor 51a is connected to the connection portions 29a and 29b of the circuit board 29. Further, while the shield conductor 51b is in a state in which tension is applied in the extending direction of the transmission cable 51, the center conductor 51a is connected in the same direction with a margin in length. Therefore, even when a bending moment acts on the imaging device 20A and a tensile stress acts on the central conductor 51a during an angle operation of the endoscope 2, the central conductor 51a is absorbed by the excess length of the central conductor 51a, and the central conductor 51a is absorbed. No stress acts on the connecting portion between 51a and the circuit board 29. As a result, the connection state between the central conductor 51a of the transmission cable 51 and the circuit board 29 can be stably maintained, and the disconnection of the power path or the signal path can be prevented.

Further, since the connection position between the shield conductor 51b and the capacitor 31 is located on the distal end side of the insertion portion 6 with respect to the connection position between the center conductor 51a and the circuit board 29, a structure that is strong against the bending moment acting on the imaging device 20A is provided. Will be realized.

(Second Example of Imaging Device)
FIG. 4 shows a second example of the configuration of the imaging device mounted on the distal end portion 10 of the insertion portion 6. FIG. 5 is a sectional view taken along line BB shown in FIG. The same or equivalent parts as those of the image pickup apparatus 20A shown in the first example are designated by the same or corresponding reference numerals to simplify or omit the description.

In the imaging device 20B shown in FIGS. 4 and 5, the orientation of the capacitor 32 with respect to the longitudinal direction of the insertion portion 6 is different from that of the first example, and the capacitor 32 is installed so that the longitudinal direction thereof is orthogonal to the longitudinal direction of the insertion portion 6. ing. Also in this example, similarly to the first example, the capacitor 32 mounted on the connection part 29b of the circuit board 29 is closer to the base end side of the insertion part 6 than the prism 23 and orthogonal to the longitudinal direction of the insertion part 6. It is provided at a position overlapping the shadow of the prism 23 projected on the plane.

The capacitor 32 of the present example is arranged a little distance from the heat transfer film 35 provided on the surface of the bonding member 23B of the prism 23 on the base end side of the insertion portion 6, but the negative electrode 34a and the heat transfer film 35. A spacer 36 having high thermal conductivity and conductivity is provided between the capacitors, and the capacitor 32 contacts the heat transfer film 35 via the spacer 36. Since the spacer 36 is provided only between the negative electrode 34a and the heat transfer film 35, the positive electrode 34b and the negative electrode 34a of the capacitor 32 do not short-circuit.

Further, the shield conductor 51b of the transmission cable 51 is connected to the negative electrode 34a of the capacitor 32, as in the first example. While the shield conductor 51b is in tension in the extending direction of the transmission cable 51, the center conductor 51a is connected to the connecting portions 29a and 29b of the circuit board 29 with a sufficient length in the same direction. Connected.

According to the configuration of the second example described above, the capacitor 32 comes into contact with the heat transfer film 35 via the spacer 36 provided between the negative electrode 34a and the heat transfer film 35, so that the Joule heat generated in the capacitor 32 is generated. Is conducted to the heat transfer film 35 through the spacer 36. Therefore, similar to the effect of the configuration of the first example, the heat radiation path of the Joule heat generated in the capacitor 32 can be strengthened. It should be noted that the respective effects regarding the reduction of the diameter of the insertion portion 6 of the endoscope 2, the enhancement of the ground function, and the maintenance of the connection state between the central conductor 51a of the transmission cable 51 and the circuit board 29 are the same as those in the first example.

(Third example of imaging device)
FIG. 6 shows a third example of the configuration of the imaging device mounted on the distal end portion 10 of the insertion portion 6. FIG. 7 is a top view of the image pickup apparatus shown in FIG. The same or equivalent parts as those of the image pickup apparatus 20B shown in the second example are designated by the same or corresponding reference numerals to simplify or omit the description.

The holding member 25 included in the imaging device 20C illustrated in FIGS. 6 and 7 extends from the light blocking member 45 and covers two opposite side surfaces of the rectangular prism 23A parallel to the optical axis O illustrated in FIG. 7 and the condenser 33 from both sides. It has a pair of plate-shaped frame members 71. Like the light blocking member 45, the frame member 71 is formed of a metal having conductivity, and the light blocking member 45 extends toward the proximal end side of the insertion portion 6 in the longitudinal direction. The frame member 71 enhances the rigidity of the imaging device 20C.

Similar to the second example, the condenser 33 of the present example is provided on the base end side of the insertion section 6 with respect to the prism 23 and at a position overlapping with the shadow of the prism 23 projected on a plane orthogonal to the longitudinal direction of the insertion section 6. ing. Further, similar to the second example, the heat transfer film 35 provided on the surface of the bonding member 23B of the prism 23 is disposed slightly apart from the heat transfer film 35 on the base end side of the insertion portion 6, but the heat transfer film is connected to the negative electrode 34a. A spacer 36 having high thermal conductivity and conductivity is provided between the films 35, and the capacitor 33 contacts the heat transfer film 35 via the spacer 36. Further, a spacer 37 having high thermal conductivity and conductivity is provided between the negative electrode 34a of the capacitor 33 and one of the pair of frame members 71, and the capacitor 33 contacts the frame member 71 via the spacer 37. .. The shield conductor 51b of the transmission cable 51 is connected to the negative electrode 34a of the capacitor 33. While the shield conductor 51b is in tension in the extending direction of the transmission cable 51, the center conductor 51a is connected to the connecting portions 29a and 29b of the circuit board 29 with a sufficient length in the same direction. Connected.

According to the configuration of the third example described above, the capacitor 33 contacts not only the heat transfer film 35 but also the frame member 71 via the spacer 37 provided between the negative electrode 34a and the frame member 71, so that the capacitor 33 The Joule heat generated in 33 is also conducted to the frame member 71 via the spacer 37. Therefore, the heat radiation path for the Joule heat generated in the capacitor 33 can be further strengthened. The respective effects relating to the reduction of the diameter of the insertion portion 6 of the endoscope 2, the enhancement of the ground function, and the maintenance of the connection state between the central conductor 51a of the transmission cable 51 and the circuit board 29 are the same as those in the first example and the second example. The same is true.

Note that, as shown in FIG. 8, the entire light shielding member 45 extends to the proximal end side in the longitudinal direction of the insertion portion 6, covers the prism 23, the capacitors 31 to 33, and the circuit board 29, and is surrounded by the light shielding member 45. The space may be filled with an insulating resin 81 having high thermal conductivity. According to this configuration example, since the entire resin 81 serves as a heat conduction path, sufficient heat dissipation can be obtained without contacting the capacitor 31 with the heat transfer film 35. As a result, the capacitor 31 can be mounted at a position away from the prism 23.

In the first to third examples described above, the configuration using the prism (cubic prism) 23 having the rectangular prism 23A and the bonding member 23B joined to the reflecting surface 23b thereof has been described, but only the rectangular prism 23A is used. The present invention can be applied to the configuration used. In that case, the heat transfer film 35 is provided on the reflection surface 23b of the rectangular prism 23A, and the condenser 31 is brought into contact with the heat transfer film 35.

As described above, the endoscope disclosed in the present specification,
Shooting lens,
A prism on which the photographing light is incident through the photographing lens,
A solid-state image sensor attached to the exit surface of the prism,
A circuit board connected to the solid-state imaging device,
An electronic component mounted on the circuit board, comprising:
The electronic component is mounted on the base end side of the endoscope with respect to the reflecting surface of the prism, at a position overlapping with the shadow of the prism projected on a plane orthogonal to the longitudinal direction of the insertion portion of the endoscope. It

Further, a holding member for holding the taking lens,
A heat transfer film provided on the reflecting surface of the prism and in contact with the holding member,
The electronic component is in contact with the heat transfer film.

Further, the prism includes a bonding member that is bonded to the reflection surface to protect the reflection surface,
The endoscope is
A holding member for holding the photographing lens,
A heat transfer film provided on the surface of the bonding member of the prism and in contact with the holding member,
The electronic component is in contact with the heat transfer film.

In addition, a holding member for holding the photographing lens is provided,
The holding member includes a frame member that is connected to a housing portion that holds the photographing lens and that covers the two facing surfaces of the prism parallel to the photographing light and the electronic component,
The electronic component is in contact with the frame member.

In addition, a transmission cable electrically connected to the circuit board and extending to the base end side of the insertion portion is provided,
The transmission cable is a coaxial cable in which the periphery of the central conductor electrically connected to the circuit board is shielded by a shield conductor.
The shield conductor is connected to the electronic component.

The connection position between the shield conductor and the electronic component is closer to the tip end side of the insertion portion than the connection position between the center conductor and the circuit board.

Further, the shield conductor is electrically connected to the negative electrode terminal of the electronic component.

The holding member and the heat transfer film are made of metal.

Further, the holding member and the heat transfer film are made of metal having conductivity.

The frame member is made of metal.

2 Endoscope 6 Insertion part 10 Tip part 20A, 20B, 20C Imaging device 21 Photographing lens 23 Prism 23A Right angle prism 23B Bonding member 23a Incident surface 23b Reflective surface 23c Exit surface 25 Holding member 27 Image sensor (solid-state imaging device)
29 Circuit boards 29a, 29b Connection part 29C Connection parts 31-33 Capacitors (electronic parts)
34a Negative electrode 34b Positive electrode 35 Heat transfer film 36 Spacer 37 Spacer 41 Lens holder 43 Housing part 45 Light blocking member 46 Cover glass 47 High thermal conductivity resin 51 Transmission cable 51a Center conductor 51b Shield conductor 71 Frame member

Claims (5)

Shooting lens,
A prism on which photographing light is incident through the photographing lens,
A solid-state image sensor mounted on the exit surface of the prism,
A circuit board connected to the solid-state imaging device,
An electronic component mounted on the circuit board,
A transmission cable electrically connected to the circuit board and extending to the proximal end side of the insertion portion,
An endoscope having:
The transmission cable includes a coaxial cable in which the periphery of a central conductor electrically connected to the circuit board is shielded by a shield conductor,
The electronic component is mounted on the base end side of the endoscope with respect to the reflecting surface of the prism, at a position overlapping with the shadow of the prism projected on a plane orthogonal to the longitudinal direction of the insertion portion of the endoscope. An endoscope that is located on the opposite side of the optical axis of the taking lens from the solid-state imaging device side. The endoscope according to claim 1, wherein
A holding member for holding the photographing lens,
The holding member has a pair of frame members that extend to the base end side while covering the two surfaces of the prism that are orthogonal to the entrance surface and the exit surface of the prism,
An endoscope in which the electronic component is in contact with one of the pair of frame members via a heat conductive spacer. The endoscope according to claim 2, wherein
The endoscope in which the frame member is made of metal. The endoscope according to any one of claims 1 to 3,
An endoscope in which the shield conductor is electrically connected to a negative electrode terminal of the electronic component. The endoscope according to claim 3,
The endoscope, wherein the connection position of the shield conductor and the electronic component is closer to the distal end side of the insertion section than the connection position of the central conductor and the circuit board.

Images