JPWO2016185554A1 - Imaging unit and endoscope - Google Patents

Abstract

The imaging unit includes a substrate on which a solid-state imaging device is mounted, a high heating element that is an electronic component mounted on the substrate and can be a heating element, a surface of the substrate, and an outer surface of the solid-state imaging device mounted on the substrate An insulating member that covers an outer surface of the high heat generating element mounted on the substrate, an outer surface of an electronic component other than the high heat generating element, a conductive heat conductive resin member provided in close contact with the insulating member, and one end portion And the other end portion, one end portion is disposed in the conductive heat conductive resin member, and the other end portion is disposed at a position spaced a predetermined distance from the substrate.

Description

  The present invention relates to an imaging unit in which a solid-state imaging device and an electronic component constituting a driving circuit for the solid-state imaging device are mounted on a circuit board, and an endoscope having the imaging unit.

In recent years, solid-state imaging devices (hereinafter abbreviated as imaging units) are used for video cameras, electronic still cameras, and electronic endoscopes (hereinafter abbreviated as endoscopes).
The endoscope is provided with an illumination optical system and an imaging optical system having an imaging unit at the distal end of the insertion portion. The imaging unit is provided with a solid-state imaging device and a substrate to which the solid-state imaging device is connected, and electronic components such as a capacitor and an IC chip are mounted on the substrate.

  In an endoscope, when the temperature of the solid-state image sensor rises due to self-heating, image quality deterioration due to an increase in dark current occurs. For this reason, it is important to ensure heat dissipation and thermal stability of the solid-state imaging device.

  Note that some electronic components mounted on the substrate can generate heat and serve as a heat source, and the heat generated from the electronic components in the imaging unit causes the temperature of the solid-state imaging device to rise.

  For this reason, many proposals have been made to conduct heat generated from electronic components mounted on a substrate to a heat radiating body and to radiate heat to the outside by the heat radiating body.

  For example, Japanese Unexamined Patent Application Publication No. 2012-50703 discloses an imaging apparatus and an electronic endoscope apparatus that efficiently dissipate heat generated by an imaging head. The imaging apparatus includes a flexible cable connected to an imaging head having an imaging element, and the cable is connected to a flexible printed circuit board and a heat source of the imaging head or in the vicinity of the heat source to heat in the axial direction of the cable. And a high thermal conductive member that conducts heat.

  In the above-described invention, the high thermal conductivity member is a fiber bundle configured by bundling a plurality of filamentous wires, and the fiber bundle is divided into a plurality of fiber bundles at the end on the imaging head side. Each end of the divided fiber bundle is connected to a different position (a heat generating component or the vicinity thereof) of the imaging head.

  According to this configuration, it is possible to dissipate heat generated in the imaging head via the fiber bundle in the cable axis direction.

  However, the work of dividing the end of the fiber bundle into a plurality of fiber bundles, and the work of connecting each end of the divided fiber bundle without making electrical contact with different positions are troublesome and time-consuming work. Met.

  The present invention has been made in view of the above circumstances, and heat generated from a solid-state imaging device and heat generated from an electronic component mounted on a substrate are further efficiently radiated to prevent image quality deterioration due to heat. An object of the present invention is to provide an imaging unit and an endoscope having the imaging unit.

  An imaging unit according to one embodiment of the present invention includes a substrate on which a solid-state imaging device is mounted, a high heating element that can be a heating element as an electronic component mounted on the substrate, a surface of the substrate, and a mounting on the substrate An insulating member that covers the outer surface of the solid-state imaging device, the outer surface of the high heat generating element mounted on the substrate, and the outer surface of an electronic component other than the high heat generating element, and is provided in close contact with the insulating member A conductive heat conductive resin member, one end portion and the other end portion, wherein the one end portion is disposed in the conductive heat conductive resin member, and the other end portion is separated from the substrate by a predetermined distance. And a heat dissipating member arranged at the position.

  An endoscope according to one embodiment of the present invention includes the imaging unit.

The figure explaining the endoscope incorporating the imaging unit of this invention The figure explaining an image pick-up part Diagram explaining the imaging unit The figure which shows the imaging unit seen from the arrow Y3B direction of FIG. 3A The figure explaining the state which unraveled the strand wire of the cable for heat dissipation to the strand, and was distributed and arranged in the conductive heat conductive resin member The figure explaining the structure which disperse | distributed and arrange | positioned the unraveled strand of the thermal radiation cable in the high heat conductive member provided in the conductive heat conductive resin member The figure explaining the structural example which electrically connects the copper wire which is the single wire of the cable for thermal radiation to the 1st ground layer

Embodiments of the present invention will be described below with reference to the drawings.
In each drawing used in the following description, the scale of each component may be different in order to make each component large enough to be recognized on the drawing. The present invention is not limited only to the number of components described in these drawings, the shape of the components, the ratio of the sizes of the components, and the relative positional relationship between the components.

  An electronic endoscope system 1 shown in FIG. 1 includes an electronic endoscope (hereinafter abbreviated as an endoscope) 2 having an imaging unit (see reference numeral 50 in FIG. 2) of the present invention, which will be described later, and a light source device 3. A video processor 4 and a monitor 5 as a display device.

The endoscope 2 includes an insertion part 5, an operation part 6, and a universal cable 7 that is an electric cable. The insertion portion 5 of the endoscope 2 includes a distal end portion 8, a bending portion 9, and a flexible tube portion 10 in order from the distal end.
An imaging unit is built in the distal end portion 8 of the insertion portion 5.

  The operation unit 6 is connected to the proximal end side of the flexible tube unit 10 constituting the insertion unit 5. The operation unit 6 is provided with a bending operation knob 11 and the like for bending the bending portion 9 of the insertion portion 5.

A universal cable 7 extends from the operation unit 6. At the end of the universal cable 7, an endoscope connector 12 that is detachably attached to the light source device 3 is provided. A video connector 13A of a video cable 13 is detachably connected to the endoscope connector 12.
Reference numeral 13B denotes a processor connector, which is provided at the other end of the video cable 13 and is detachable from the video processor 4.

The video processor 4 is electrically connected to a monitor 5 that displays an endoscopic image. The imaging signal transmitted from the imaging unit of the endoscope 2 is processed into a video signal by the video processor 4 and output to the monitor 5.
Reference numeral 15 denotes an illumination window, which constitutes an illumination optical system. Reference numeral 42 denotes an observation window, which constitutes an imaging optical system.

As shown in FIG. 2, the imaging unit 30 includes an observation optical unit 40 and an imaging unit 50.
The observation optical unit 40 is configured by fixing an observation window 42, which is an optical member, a single or plural optical lenses 43, a filter 44, and a diaphragm 45 in a stainless steel lens frame 41.

The imaging unit 50 is mainly composed of a solid-state imaging device (hereinafter abbreviated as imaging device) 51, a circuit board 52, and a signal cable 53.
The image sensor 51 is a CCD, a CMOS, or the like. A glass lid 54 is bonded and fixed to the light receiving surface 51 a side which is the front surface of the image sensor 51. Further, a connection part 51b is arranged on the light receiving surface 51a side.

  A cover glass 55 centered with respect to the center of the light receiving surface 51a is further adhered and fixed to the front surface of the glass lid 54. The cover glass 55 is integrally fixed to a predetermined position on the inner surface of the imaging holder 56 by adhesion or bonding. The imaging holder 56 is made of ceramic.

  A proximal end portion of the lens frame 41 constituting the objective lens unit 40 is disposed on the inner surface of the distal end portion of the imaging holder 56. The lens frame 41 and the imaging holder 56 are fixed together by, for example, an adhesive 46 after completing the position adjustment such as focusing.

The circuit board 52 includes a first circuit board 57 and a second circuit board 58.
A circuit board 52 composed of a first circuit board 57 and a second circuit board 58 will be described with reference to FIGS. 3A and 3B.
The first circuit board 57 shown in FIG. 3A is a flexible printed board having flexibility, and the second circuit board 58 is a laminated board. The second circuit board 58 includes a first mounting board part 58a, a second mounting board part 58b, a grounding board part 58c, a distal leg leg board part 58d constituting the first leg part, a proximal leg leg part 58dr, a cable. A connection portion 58e and the like are provided.

One surface of the first circuit board 57 includes a plurality of image sensor connection portions (not shown), a wiring pattern (not shown), and a plurality of second substrate connection portions (not shown).
The image sensor connection portion is provided on the distal end side of the one surface, and the second substrate connection portion is provided on the proximal end side of the one surface. The wiring pattern electrically connects the image sensor connection portion and the second substrate connection portion.

  The image sensor connection portion is electrically connected to the connection land 51b on the light receiving surface 51a side via the first pump 61. The first circuit board 57 is bent and extended to the back side of the image sensor 51. The second substrate connecting portion (not shown) is electrically connected via a second pump 62 to a first substrate connecting portion (not shown) provided on the distal leg side substrate portion 58d1.

  The first circuit board 57 including the electrical connection part between the connection land 51b and the image sensor connection land of the first circuit board 57 and the electrical connection part between the second board connection part and the first board connection part is as follows. Insulated and sealed with a sealing resin 63.

The second circuit board 58 will be described with reference to FIGS. 3A and 3B.
As shown in FIG. 3A, the front surface of the second circuit board 58 is disposed on the rear surface of the image sensor 51. The first mounting substrate portion 58a includes a first electronic component wiring layer 58w1 that is a wiring portion on the one surface side of the substrate that is the upward direction in the drawing.

The second mounting board portion 58b includes a second electronic component wiring layer 58w2 on the other side of the board in the downward direction in the figure, which is the opposite side of the board. The ground substrate portion 58c includes a first ground layer 58g1 on one side of the substrate and a second ground layer 58g2 on the other side of the substrate.
The distal-side leg board portion 58d is provided with the above-described first board connecting portion on the other surface side of the board. The cable connection portion 58e is a convex portion that protrudes from the base end surface of the base end side leg portion 58dr to the image sensor distal side. The one side of the board and the other side of the board of the cable connection part 58e, which are convex parts, are line wiring layers 58l1 and 58l2, and the line connection part 64 shown in FIG. 3B is provided.

  As shown in FIGS. 3A and 3B, the first electronic component wiring layer 58w1 of the first mounting substrate portion 58a is provided with an electronic component connecting portion (not shown), and chip components 71, 72, which are electronic components, 73 is implemented. For example, the first chip component 71 is a high heating element.

  The second electronic component wiring layer 58w2 of the second mounting substrate portion 58b is provided with an electronic component connecting portion (not shown), and chip components 74 and 75 that are electronic components are mounted thereon.

  As shown in FIG. 2, the signal cable 53 includes, for example, a first composite cable 53a and a second composite cable 53b. Various wires 53c such as signal wires and electric wires are inserted into the first composite cable 53a and the second composite cable 53b.

  The signal lines and electric wires of the first composite cable 53a are connected to the corresponding line connection portions 64 provided in the line wiring layer 58l1 of the cable connection portion 58e, respectively. On the other hand, the signal lines and electric wires of the second composite cable 53b are connected to corresponding line connection portions (not shown) provided in the line wiring layer 5812.

Reference numeral 59 denotes a heat radiating cable, which is disposed along the signal cable 53, for example. Reference numeral 59a is, for example, a copper wire 59a that is a high thermal conductivity member and has a higher thermal conductivity than the conductive thermal conductive resin member 77 filled with a metal filler. The copper wire 59 a is inserted into the heat radiating cable 59, and the tip portion is exposed from the tip surface of the heat radiating cable 59.
Although not shown, the substrate portions 58a, 58b, 58c, and 58d are provided with through vias, wirings, and the like for electrically connecting predetermined connection portions.

  In the present embodiment, the outer surface of the glass lid 55, the outer surface of the image sensor 51, the surface of the first electronic component wiring layer 58w1 of the first mounting substrate portion 58a, and the surface of the second electronic component wiring layer 58f2 of the second mounting substrate portion 58b. Insulating members having insulating properties on the surfaces of the electronic components 71, 72, 73 mounted on the first electronic component wiring layer 58w1 and the surfaces of the electronic components 74, 75 mounted on the second electronic component wiring layer 58w2 76 is uniformly coated.

  The insulating member 76 of this embodiment is an electric insulator (1.0 × 10 16j Ωm) having a high electric resistivity, and is an insulating thin film. The insulating thin film covers a predetermined surface including the above-described portions by vacuum deposition.

  In addition, the surface of the cable connection part 58e, the signal line connected to the line connection part, and the line connection part and the electric wire is insulated by an insulating thin film or sealing resin.

In this embodiment, a conductive heat conductive resin member 77 is provided on the insulating thin film that is the insulating member 76. The conductive heat conductive resin member 77 is a resin in which a flexible resin member is filled with a metal filler having a low electrical resistivity such as silver (1.59 × 10 ⁻⁸ jΩm) gold (2.21 × 10 ⁻⁸ jΩm). Yes, it is applied on the insulating thin film and filled in a predetermined portion including the surface of the electronic component 71-75 that is not to be short-circuited.
The conductive heat conductive resin member 77 has a higher thermal conductivity than the insulating high heat conductive member. In the present embodiment, the conductive heat conductive resin member 77 is an anisotropic conductive heat conductive resin member.

  The anisotropic conductive heat conductive resin member positions heat generated from the electronic components 71-75 mounted on the first mounting substrate portion 58a and the second mounting substrate portion 58b to the outside of the conductive heat conductive resin member 77. To move toward the copper wire 59a.

  And the front-end | tip part of the copper wire 59a which is a highly heat conductive member is arrange | positioned inside the conductive heat conductive resin member 77. FIG. The copper wire 59a is a single wire having a predetermined outer diameter, and is provided in a state where the base end portion is exposed, for example, in the operation unit 6 separated from the image pickup device 51.

  As a result, the heat moved toward the outside of the conductive heat conductive resin member 77 is transferred to the distal end portion of the copper wire 59a, and then moved toward the proximal end portion to be radiated.

  As described above, the insulating thin film as the insulating member 76 is formed on the outer surface of the imaging device 51, the surface of the first electronic component wiring layer 58w1, the surfaces of the electronic components 71, 72, 73 mounted on the wiring layer 58w1, and the second electrons. The conductive heat conductive resin member 77 is filled on the insulating thin film after being provided on the surface of the component wiring layer 58w2 and the surfaces of the electronic components 74 and 75 mounted on the wiring layer 58w2. The member 77 is adhered to the insulating thin film.

  As a result, the insulation between the conductive heat conductive resin member 77, the electronic component wiring layers 58w1, 58w2, and the electronic components 71-75 can be ensured by the insulating thin film.

In addition, since the electronic components 71-75 mounted on the mounting board portions 58a and 58b and the conductive heat conductive resin member 77 are insulated by the insulating thin film, heat generated from the electronic components 71-75 is generated. It can be efficiently transmitted to the conductive heat conductive resin member 77 through the insulating thin film.
The thinner the insulating thin film, the more efficiently the heat generated from the electronic components 71-75 is transferred to the conductive heat conductive resin member 77.

  Further, the conductive heat conductive resin member 77 is an anisotropic conductive heat conductive resin member, so that the heat generated from the electronic components 71-75 is transferred to the copper wire located outside the conductive heat conductive resin member 77. It can be moved toward 59a. In other words, the heat generated from the electronic components 71-75 is prevented from moving toward the image sensor 51 by the anisotropic conductive heat conductive resin member.

  As a result, the heat generated from the electronic components 71-75 is conducted to the conductive heat conductive resin member 77 and then conducted to the copper wire 59 a of the heat radiating cable 59 to be radiated. Therefore, it is possible to more reliably prevent the heat generated from the electronic component 71-75 from being conducted to the image sensor 51 and the temperature of the image sensor 51 from being increased by the heat generated from the electronic component 71-75.

  In the above-described embodiment, the tip of the copper wire 59a, which is a single wire having a predetermined outer diameter, is disposed inside the conductive heat conductive resin member 77. However, the copper wire 59a disposed inside the conductive heat conductive resin member 77 is not limited to a single wire, and a plurality of strands 59c may be disposed as shown in FIG. 4A. .

  The heat radiating cable 59 of the present embodiment has a stranded wire 59b, and one stranded wire 59b is configured by collecting together a plurality of strands 59c which are a plurality of copper wires. In the conductive heat conductive resin member 77, a plurality of strands 59c loosened from the stranded wires 59b are distributed.

  According to this configuration, the plurality of strands 59 c are dispersed and arranged at predetermined intervals inside the conductive heat conductive resin member 77, and are generated from the electronic components 71-75 and conducted to the conductive heat conductive resin member 77. The conducted heat can be conducted to the plurality of strands 59c, and the heat radiation by the heat radiation cable 59 can be performed more efficiently.

  As shown in FIG. 4B, a plate-like member 59d formed by, for example, a copper plate, which is a high heat conduction member, in a predetermined shape is disposed inside the conductive heat-conductive resin member 77, and one surface or the other of the plate-like member 59d is arranged. A plurality of strands 59c may be distributed on the surface at predetermined intervals.

  According to this configuration, the heat generated from the electronic components 71-75 and conducted to the conductive heat conductive resin member 77 is conducted to the plate member 59d, and then conducted to the plurality of strands 59c for more efficiency. Heat dissipation can be realized.

Further, as shown in FIG. 5, the copper wire 59a (or the stranded wire 59b) may be electrically connected to, for example, the connection portion 58j of the through via 58h that is electrically connected to the first ground layer 58g1. Good.
As a result, the conductive heat conductive resin member 77 is at the ground level, and an electrically independent ground is provided at the distal end portion 8 of the endoscope 2 to improve the image quality without hindering the diameter reduction of the distal end portion 8. .

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

Claims (6)

A substrate on which a solid-state image sensor is mounted;
A high heating element that can be a heating element, which is an electronic component mounted on the substrate,
An insulating member that covers a surface of the substrate, an outer surface of the solid-state imaging device mounted on the substrate, an outer surface of the high heat generating element mounted on the substrate, and an outer surface of an electronic component other than the high heat generating element; ,
A conductive thermal conductive resin member provided in close contact with the insulating member;
A heat dissipating member having one end and another end, the one end being disposed in the conductive heat conductive resin member, and the other end being disposed at a predetermined distance from the substrate; ,
An imaging unit comprising:   The imaging unit according to claim 1, wherein the conductive heat conductive resin member is filled with a metal filler.   The imaging unit according to claim 2, wherein the conductive heat conductive resin member is an anisotropic conductive heat conductive resin member that moves heat generated from the heating element in a predetermined direction.   The imaging unit according to claim 1, wherein the insulating member is an insulating thin film.   The imaging unit according to claim 1, wherein the heat radiating member is a cable member, and includes a copper wire that is inserted into the outer skin.   An endoscope comprising the imaging unit according to any one of claims 1 to 5.

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