JP2014000314A - Heat radiation structure of endoscope distal end - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat radiation structure of an endoscope distal end efficiently radiating heat and having a small endoscope distal end.SOLUTION: The heat radiation structure of the endoscope distal end includes: an imaging device 22 provided at an imaging device section 18 of the endoscope; a shield member 40; and a circuit board 24 provided on a backside of the imaging device 22. The shield member 40 covers peripheries of transmission cables 28. A cavity 34 is provided on a surface in an opposite side of the imaging device 22 of the circuit board 24. The transmission cable 28 fetches an image signal from the imaging device 22. The cavity 34 includes a thermoelement 36 for radiating heat generated from the imaging device 22. A connection plate in the heat radiation side of the thermoelement 36 is joined with the shield member 40.

Description

  The present invention relates to a heat dissipation structure for an endoscope distal end portion, and more particularly to a heat dissipation structure having a small distal end portion.

  Conventionally, as a proactive heat countermeasure for the image sensor at the distal end of the endoscope, a structure that dissipates heat by fixing a heat radiating member having high thermal conductivity in the vicinity of the image sensor and active components to the frame of the image sensor is known. (Patent Document 1). In addition, a structure has also been proposed in which a member having high thermal conductivity is brought into close contact with the image pickup element to dissipate heat toward the composite cable (Patent Document 2). However, in recent years, with the mounting of a CMOS image sensor (hereinafter CIS), a multi-functional circuit that generates a lot of heat may be mounted on the same chip. For this reason, image degradation due to temperature rise cannot be prevented with the heat dissipation structure alone, and a structure for more efficiently dissipating heat by providing a thermoelectric element in the longitudinal direction of the circuit board has been proposed (Patent Document 3).

JP 2002-291893 A JP 2010-279527 A JP 2010-035815 A

  However, when the thermoelectric element is mounted in the longitudinal direction, there is a problem that the hard portion at the tip of the endoscope becomes large.

  Accordingly, an object of the present invention is to provide a heat dissipation structure for an endoscope distal end portion that efficiently radiates heat and has a small endoscope distal end portion.

  An endoscope distal-end heat dissipation structure according to the present invention includes an imaging element provided at a distal-end rigid part of an endoscope, a shield member that covers a peripheral surface of a transmission cable for taking out an image signal from the imaging element, A circuit board provided on the back surface of the image sensor, a cavity is provided on the surface of the circuit board opposite to the image sensor, and a thermoelectric element that radiates heat generated from the image sensor is provided in the cavity. The heat dissipation surface of the thermoelectric element is joined to the shield member.

  Moreover, it is preferable that a thermoelectric element has a heat absorption part in which the heat absorption plate was provided, and a heat radiation part in which the heat dissipation plate was provided with a heat dissipation land, and a portion excluding the heat dissipation part was embedded in the cavity. A cable mounting land may be provided on the side surface of the circuit board.

  In addition, the circuit board includes an overhanging portion having a surface that is in contact with the image pickup device and an area substantially equal to the image pickup device, an intermediate portion extending from the center of the overhanging portion toward the rear end and having a smaller cross section than the overhanging portion, The cable may further include a mounting portion that extends in the rear end direction from the portion and has a cross section that is larger than the intermediate portion and smaller than the protruding portion, and a cable mounting land may be provided on the side surface of the mounting portion. The overhanging portion is preferably provided with an electronic component. By disposing the electronic component on the overhang portion, the tip portion can be further reduced in size. The image sensor may be a CIS. Compared with a CCD, a CIS often includes a multi-functional circuit and may generate a large amount of heat. However, the structure of the present invention enables space-saving and efficient heat dissipation. The imaging element is preferably a BGA type. In the case of the BGA type, the external electrode connection land is not necessary, and the tip rigid portion can be further reduced in size.

  ADVANTAGE OF THE INVENTION According to this invention, the heat dissipation structure of the endoscope front-end | tip part which thermally radiates efficiently and an endoscope front-end | tip part is small can be provided.

1 is an overall view of an endoscope to which an embodiment of the present invention is applied. It is a figure showing the longitudinal cross-section of the image pick-up element part in 1st Embodiment. It is the three-dimensional view which looked at FIG. 2 from the base end direction. It is a perspective view of the image sensor part in a 2nd embodiment. It is the three-dimensional view which looked at FIG. 4 from the base end direction.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. Referring to FIG. 1, an endoscope 10 includes an endoscope flexible tube 11 that is inserted into a body, an operation unit 15 that is gripped by a user to operate the endoscope 10, and the endoscope 10. Is connected to a processor (not shown). The endoscope flexible tube 11 includes a flexible portion 12 having flexibility, a bending portion 13 connected to the distal end of the flexible portion 12, and a distal end rigid portion 14 connected to the distal end of the bending portion 13. Prepare. The operation unit 15 is connected to the connector 16 via the universal cable 17.

  The in-vivo optical image photographed at the distal end rigid portion 14 is converted into an electrical signal by the imaging element portion 18 provided at the distal end rigid portion 14. The electrical signal is image processed in the processor via the universal cable 17 and the connector 16, and the image is observed by the operator.

  With reference to FIG. 2, the structure of the image pick-up element part 18 is demonstrated. The image sensor unit 18 includes a CIS image sensor 22 protected by a cover glass 20, and a circuit board 24 is provided on the back surface of the image sensor 22. A plurality of cable attachment lands 26 are provided on the side surface of the circuit board 24 that is a multilayer ceramic, and the connection portion 30 of the transmission cable 28 is connected to the cable attachment lands 26. An electrical signal from the image sensor 22 is transmitted to the proximal end portion of the endoscope via the transmission cable 28. Further, the external electrode 32 of the image sensor 22 is connected to the cable mounting land 26.

  A cavity 34 is formed at the center of the surface of the circuit board 24 opposite to the imaging element 22. The cavity 34 is provided with a thermoelectric element 36 that radiates heat generated from the imaging element 22. The thermoelectric element 36 has a structure in which N-type and P-type semiconductors are alternately connected in series between the heat-absorbing surface 35 and the heat-dissipating surface 37, and a portion excluding the heat-dissipating surface 37 is embedded in the cavity 34. That is, the heat radiating surface 37 protrudes from the circuit board 24. A connection circuit for connecting a plurality of semiconductors of the thermoelectric element 36 in series is formed at the bottom of the cavity 34, that is, the surface close to the imaging element 22. Further, the heat radiating surface 37 on the heat generating side of the thermoelectric element 36 is provided at a position where it does not contact the circuit board 24. Here, a space is formed between the thermoelectric element 36 and the cavity 34 or is filled with a heat insulating resin. Thereby, heat can be prevented from conducting from the heat radiating side to the heat absorbing side.

  The heat dissipation surface of the thermoelectric element 36 is connected to the connection plate 41 and is connected to a shield wire bundle (shield member) 40 via a heat dissipation land 38 (see FIG. 3) to form a heat dissipation path. The shield wire bundle 40 is formed by once soldering a bundle of shield wires, and then joined to the heat radiation land 38 by soldering or the like. Thus, when the shield wire bundle 40 is joined to the heat radiation land 38, the heat radiation efficiency is significantly increased as compared with the case where the shield wire bundle 40 is not joined.

  With reference to FIG. 3, the three-dimensional structure of the image sensor section 18 will be described. The surface of the image sensor 22 parallel to the front end surface is a square shape of about 3 mm square, and the surface of the circuit board 24 in contact with this surface is substantially the same shape. A cavity 34 having a square shape of 2 mm square and a depth of 1 mm is provided on the surface of the circuit board 24 opposite to the imaging element 22. A thermoelectric element 36 having a height higher than the depth of the cavity 34 is disposed in the cavity 34. The heat absorption surface 35 of the thermoelectric element 36 is disposed closer to the image sensor 22, and the heat radiation surface 37 (see FIG. 2) of the thermoelectric element 36 is disposed at the opposite position. Further, on the same plane as the opening of the cavity 34, the electronic component 21 is disposed so as to surround the opening of the cavity 34.

  A connection plate 41 is provided on the upper surface of the heat radiating surface 37 of the thermoelectric element 36 that is provided inside the cavity 34 and protrudes. On the surface of the connection plate 41, the heat radiation land 38 and the power electrode land 42 that is electrically connected to the power electrode of the thermoelectric element 36 are exposed. The shield wire bundle 40 (see FIG. 2) is connected to the heat radiation land 38. As a result, the heat transferred from the heat absorbing surface 35 of the thermoelectric element 36 to the heat radiating surface 37 is absorbed and radiated by the shield wire bundle 40, and the imaging element 22 is cooled.

  As described above, the thermoelectric element 36 is disposed in the cavity 34 provided in the circuit board 24, so that the imaging element unit 18 (see FIG. 2) does not become thick or long. More specifically, 80% or more of the thickness of the thermoelectric element 36 is accommodated in the cavity 34, and the cable can be arranged with the same size as the conventional one. Thereby, the heat dissipation structure which does not affect the dimension of the distal end rigid portion 14 of the endoscope is realized.

  Next, a second embodiment will be described with reference to FIG. The difference from the first embodiment is that the image sensor 22 is not a TCP (Tape Carrier Package) type but a BGA (Ball Grid Array) type. Thereby, as will be described in detail below, the shape of the circuit board 24 is different. The same members as those in the first embodiment are denoted by the same reference numerals.

  The surface of the circuit board 24 that is electrically connected to the image sensor 22 has a protruding portion 62 having an area substantially equal to that of the image sensor 22. The overhang 62 and the image sensor 22 are electrically connected by a BGA bump 60. From the center of the overhang portion 62 to the rear end direction, an intermediate portion 64 having a transverse section smaller than that of the overhang portion 62 is extended. A mounting portion 66 having a transverse section larger than that of the intermediate portion 64 and smaller than the overhang portion 62 extends from the intermediate portion 64 in the rear end direction. In other words, the circuit board 24 according to the second embodiment includes the overhang portion 62, the intermediate portion 64, and the attachment portion 66.

  Referring to FIG. 5, the electronic component 21 is disposed so as to surround the intermediate portion 64 around the intermediate portion 64 (not shown), that is, the overhang portion 62. Thereby, it is not necessary to separately provide an arrangement space for the electronic component 21, and the imaging element unit 18 can be designed to be small. Moreover, the cable attachment land 26 is provided on the side surface of the attachment portion 66, and the connection portion 30 (see FIG. 4) of the transmission cable 28 (see FIG. 4) is connected thereto. Here, since the image pickup device 22 is a BGA type and the external electrode 32 is not on the outer peripheral surface of the image pickup device, it is necessary to prepare a land for connection with the external electrode 32 (see FIG. 2) on the outer peripheral surface of the circuit board 24. No. Therefore, it is possible to provide the attachment portion 66 narrowly regardless of the size of the image sensor 22. That is, the transmission cable 28 connected to the cable mounting land 26 is reduced in size as compared with the first embodiment.

  As described above, in the second embodiment, the electronic component 21 can be arranged using the space of the overhang portion 62, and the transmission cable 28 can be made small along the outer peripheral surface of the attachment portion 66. Thereby, it is possible to design the image sensor unit 18 smaller than in the first embodiment.

  In addition, since there is no circuit in the geometric center part position of the circuit board 24, even if the cavity 34 is formed, a problem does not arise in an electrical configuration. Moreover, since the circuit board 24 is a laminated alumina ceramic, it is excellent in thermal conductivity and heat dissipation, and the temperature rise can be more effectively suppressed.

14 Hard end portion 22 Image sensor 24 Circuit board 26 Cable mounting land 28 Transmission cable 34 Cavity 35 Heat absorbing surface (heat absorbing portion)
36 Thermoelectric element 37 Heat radiation surface 38 Land for heat radiation 40 Shield wire bundle (shield member)
62 Overhanging portion 64 Intermediate portion 66 Mounting portion

Claims (7)

An image sensor provided at the distal rigid portion of the endoscope;
A shield member for covering a peripheral surface of a transmission cable for taking out an image signal from the image sensor;
A circuit board provided on the back surface of the imaging device,
A cavity is provided on the surface of the circuit board opposite to the imaging element, and the cavity is provided with a thermoelectric element that dissipates heat generated from the imaging element.
A heat dissipation structure for an endoscope distal end, wherein a heat dissipation surface of the thermoelectric element is joined to the shield member.   The thermoelectric element has a heat absorbing portion provided with a heat absorbing surface and a heat radiating portion provided with a heat radiating land on the heat radiating surface, and a portion excluding the heat radiating portion is embedded in the cavity. The heat dissipation structure of the endoscope front end part according to 1.   The thermoelectric element has a heat absorbing portion provided with a heat absorbing surface and a heat radiating portion provided with a heat radiating land on the heat radiating surface, and the heat radiating portion is embedded in the cavity so as to protrude from the circuit board. The heat dissipating structure for the distal end portion of the endoscope according to claim 1.   The heat dissipation structure for an endoscope distal end portion according to claim 1, wherein the cavity is formed in a central portion on a surface of the circuit board opposite to the imaging element. The circuit board has a projecting portion whose surface in contact with the image sensor has an area substantially equal to the image sensor,
An intermediate portion extending in the rear end direction from the center of the overhang portion and having a smaller cross section than the overhang portion,
The intermediate portion further extends in the rear end direction and has a cross section that is larger than the intermediate portion and smaller than the protruding portion,
The endoscope heat dissipating structure according to claim 2, wherein a cable mounting land is provided on a side surface of the mounting portion.   A connecting plate is provided on the upper surface of the heat radiating portion of the protruding thermoelectric element, and a heat radiating land and a power electrode land that is electrically connected to the power electrode of the thermoelectric element are exposed on the surface of the connecting plate. The endoscope heat-radiating structure according to claim 3, wherein the structure is joined to the shield member.   The heat dissipation structure according to claim 6, wherein the thermoelectric element includes a plurality of semiconductors, and a connection circuit of the semiconductors is formed at a bottom portion of the cavity.

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