JP6373562B2 - Endoscope - Google Patents

Description

  The present invention relates to a heat dissipation device and an endoscope for radiating heat generated by a component connected to a board using a cable.

  An endoscope that is inserted into a human body and captures an image inside the body, and an endoscope processor that receives and displays an image signal from the endoscope are known. Such an endoscope includes an image sensor at the tip, and outputs an image signal output from the image sensor to the endoscope processor. The image sensor is attached to the substrate together with various components, and is fixed to the endoscope. The image sensor and components attached to the substrate generate heat during operation. Various configurations that efficiently dissipate heat are known to prevent malfunction and destruction of the device itself due to the heat generated by the imaging device and components, and in the worst case, burns in the body. Yes. Patent Document 1 discloses a heat dissipation structure in which an external conductor of a cable is connected to a heat sink layer provided by being laminated on a printed board, and heat generated by an electric circuit or the like is transmitted to the external conductor to dissipate heat. Patent Document 2 discloses a configuration in which heat generated by an image sensor is transmitted to a peripheral member such as a water pipe by a graphite sheet.

JP 2007-142249 A JP 2010-022815 A

  However, in the configuration using the outer conductor of the cable as described in Patent Document 1, since the material of the outer conductor is determined by the required performance of the cable, it is not always possible to select a material suitable for transferring heat. is not. Therefore, there is a possibility that the heat generated by the image sensor cannot be carried to the outside sufficiently and efficiently. Similarly, in the configuration described in Patent Document 2, there is a possibility that peripheral members such as a water pipe cannot carry heat to the outside sufficiently and efficiently.

  The present invention has been made in view of these problems, and an object thereof is to obtain a heat dissipation device and an endoscope that efficiently dissipate heat generated by an image sensor connected to a substrate.

  A heat dissipation device according to a first invention of the present application is a heat dissipation device that dissipates heat generated by an image sensor, and is provided on the substrate on which the image sensor is mounted, and is electrically and thermally connected to the image sensor. A wiring member, a core wire that transmits an electrical signal from the substrate, a first shielding member that is provided on an outer periphery of the core wire and is electrically and thermally connected to the wiring member, and a contact with the first shielding member And a cable having a first heat transfer member that is provided and thermally connected to the wiring member.

  It is desirable that the first heat transfer member is provided on the outer periphery, the inner periphery, or the outer periphery and the inner periphery of the first shielding member and is thermally connected to the wiring member.

  It is desirable that the substrate is mounted on a terminal surface provided on the back surface of the imaging surface of the image sensor.

  It is desirable to further include a plurality of cables, a second shielding member provided so as to be in contact with the plurality of cables, and a second heat transfer member provided on the outer periphery of the second shielding member.

  The second shielding member is desirably provided on the outer periphery, inner periphery, or outer periphery and inner periphery of the plurality of cables.

  It is desirable that the second heat transfer member is thermally connected to the wiring member.

  The first heat transfer member is preferably made of a graphite sheet provided over the entire circumference of the outer circumference of the first shielding member, the whole circumference of the inner circumference, or the whole circumference of the outer circumference and the inner circumference.

  The second heat transfer member is preferably made of a graphite sheet provided over the entire circumference of the outer periphery, the inner circumference, or the outer circumference and the inner circumference of the second shielding member.

  The cable is preferably a coaxial cable.

  The cable may be a twisted pair cable.

  An endoscope according to a second invention of the present application includes a substrate on which an image pickup device is mounted, a wiring member provided on the substrate and electrically and thermally connected to the image pickup device, and a core wire that transmits an electric signal from the substrate. A first shielding member provided on the outer periphery of the core wire and electrically and thermally connected to the wiring member; and provided to contact the first shielding member and thermally connected to the wiring member. And a cable having a first heat transfer member.

  According to the present invention, a heat radiating device and an endoscope that efficiently radiate heat generated by an imaging device connected to a substrate are obtained.

It is the end elevation which showed roughly the endoscope provided with the thermal radiation apparatus by 1st Embodiment. It is the end elevation which showed the heat dissipation device schematically. It is an end view of the 1st cable. It is the end elevation which showed roughly the heat dissipation device by a 2nd embodiment. It is an end view of a 2nd cable. It is the end elevation which showed roughly the heat dissipation device by a 3rd embodiment. It is an end view of a 3rd cable. It is the end elevation which showed roughly the heat dissipation apparatus by 4th Embodiment. It is an end view of a 4th cable.

  Hereinafter, the 1st thermal radiation apparatus 100 by the 1st Embodiment of this invention is demonstrated using FIGS. 1-3.

  FIG. 1 shows an endoscope system 10 including a first heat dissipation device 100. The endoscope system 10 mainly includes an endoscope 20 and an endoscope processor 30. The endoscope 20 is bendable, and includes an insertion portion 21 to be inserted into an observation target, for example, a human body, a grip portion 22 to be gripped by a user, and a grip portion 22 and an internal portion via a connection tube 23. It is mainly comprised from the connector 24 which connects the endoscope processor 30. FIG. An image sensor (not shown) and the first heat radiating device 100 are stored in the distal end portion 25 of the insertion portion 21. The imaging device images an observation target and transmits an image signal to the endoscope processor 30.

  The first heat dissipation device 100 will be described with reference to FIG. The first heat dissipation device 100 includes a substrate 130 and a first cable 140 and is stored in the casing 110 together with the image sensor 120.

  The casing 110 has, for example, a cylindrical shape, and includes an outer shell 111 and a disk-shaped support portion 112 that extends in the radial direction from the inner periphery of the outer shell 111. When viewed from the axial direction of the casing 110, the support portion 112 has a cylindrical fixing hole 113.

  The imaging device 120 is a CMOS, and includes an imaging surface 121 on which a subject image is formed, and a terminal surface 122 provided on the back surface of the imaging surface 121. A plurality of ball-shaped terminals 123 arranged in a lattice shape are provided on the terminal surface 122. That is, the image sensor 120 of the present embodiment is a BGA package.

  The substrate 130 is a multilayer substrate made of a material having low thermal conductivity and having a rectangular parallelepiped shape, and includes a mounting surface 131 positioned on the image sensor 120 side, a cable surface 132 that is the back surface of the mounting surface 131, and a plurality of patterns. A wiring 137 and a plurality of vias 138 are mainly provided. The direction from the mounting surface 131 to the cable surface 132 is the thickness direction. The substrate 130 is illustrated in an enlarged manner in the thickness direction. The material of the substrate 130 is, for example, zirconia, FR4, silicon, glass, aluminum nitride, or alumina. The thermal conductivity of zirconia is 3 W / m · K, the thermal conductivity of FR4 is 0.44 W / m · K, the thermal conductivity of silicon is 168 W / m · K, the thermal conductivity of glass is 1 W / m · K, Aluminum nitride has a thermal conductivity of 150 W / m · K, and alumina has a thermal conductivity of 32 W / m · K. Note that components provided on the board 130 are not shown.

  The mounting surface 131 includes a plurality of disk-shaped circular terminals 136 arranged in a lattice pattern. The circular terminal 136 is soldered to the ball terminal 123.

  The pattern wiring 137 is provided on the inner and outer surfaces of the substrate 130 and extends in a direction perpendicular to the thickness direction of the substrate 130. The via 138 is provided inside the substrate 130 and extends in the thickness direction of the substrate 130. Vias 138 connect pattern wirings 137 provided in different layers. A plurality of side terminals 134 are provided on the side surface 133 of the substrate 130, and a plurality of planar terminals 135 are provided on the cable surface 132. The side terminal 134 and the planar terminal 135 are connected to the pattern wiring 137 or the via 138 inside the substrate 130.

  The first cable 140 is formed by wrapping three built-in coaxial cables 150 and three insulated wires 160 with an outer braided wire 141, an outer graphite sheet 142, and an outer skin 143.

  The outer net assembly wire 141 is also called a shielding member, and is formed by knitting a plurality of conductive wires made of copper into a net shape, or simply winding them. The thermal conductivity of copper is 401 W / m · k. The outer graphite sheet 142 is a sheet-like graphite and forms a heat transfer member. The outer skin 143 is made of an insulator such as vinyl. The outer graphite sheet 142 has a thickness of 17 μm to 100 μm, and the outer graphite sheet 142 having a thickness of 17 μm has a thermal conductivity of 1750 W / m · k, and the outer graphite sheet 142 having a thickness of 100 μm has a thermal conductivity. The rate is 700 W / m · k. The outer braided wire 141 is connected to the outer shell 111.

  The built-in coaxial cable 150 includes a core wire 151 made of a plurality of copper wires, an insulator 152 provided around the core wire 151, an inner mesh wire 153 provided around the insulator 152, and an inner mesh wire. 153 includes an inner graphite sheet 154 provided so as to cover 153, and an inner skin 155 provided so as to cover the inner graphite sheet 154. The insulator 152 is made of, for example, polyethylene, and the inner netting wire 153 is also called a shielding member, and is formed by braiding a conductive wire made of copper into a net shape, or simply winding a conductive wire. The inner graphite sheet 154 is a sheet-like graphite and forms a heat transfer member. The inner skin 155 is made of an insulator such as vinyl. The inner braid 153 and the inner graphite sheet 154 are in contact with each other and are thermally connected. The core wire 151 is soldered to the side terminal 134, and the inner braided wire 153 is soldered to the flat terminal 135.

  The insulated wire 160 includes an insulated core wire 161 made of a plurality of copper wires, and an insulator 162 provided around the insulated core wire 161 so as to enclose the insulated core wire 161. The insulator 162 is made of an insulator 162 such as vinyl. The insulated core wire 161 is soldered to the flat terminal 135.

  The three built-in coaxial cables 150 are alternately arranged with the three insulated wires 160 to form a cylindrical shape, and the outer mesh wire 141 covers the periphery of the cylinder. Then, the outer graphite sheet 142 covers the periphery of the outer mesh line 141, and the outer skin 143 covers the periphery of the outer graphite sheet 142. The outer braided wire 141 and the outer graphite sheet 142 are in contact with each other and are thermally connected. Further, inside the outer shell 110, the resin 170 is filled in a region other than the region occupied by the substrate 130 and the first cable 140.

  Next, the state of the first heat dissipation device 100 when the image sensor 120 generates heat will be described. When the image sensor 120 generates heat, the heat is transferred from the ball terminal 123 to the substrate 130 via the circular terminal 136. The heat transferred to the substrate 130 is transferred to the support portion 112, the pattern wiring 137, and the via 138. The heat transferred to the support 112 is transferred to the outer braided wire 141 and the outer graphite sheet 142 via the outer shell 111. On the other hand, the heat transmitted to a part of the pattern wiring 137 and the via 138 is transmitted to the inner mesh line 153 and the inner graphite sheet 154 through the flat terminal 135. Since the graphite sheet has a thermal conductivity larger than that of copper, more heat can be transmitted to the wide area faster than the outer mesh line 141 and the inner mesh line 153. That is, by providing the outer graphite sheet 142 and the inner graphite sheet 154 on the outer side of the outer mesh line 141 and the inner mesh line 153, respectively, as compared with the case where only the outer mesh line 141 and the inner mesh line 153 are provided. Thus, more heat can be absorbed from the image sensor 120 and can be dissipated.

  Further, the heat transferred to some of the pattern wirings 137 and vias 138 is transferred to the insulating core wires 161 via the plane terminals 135, and the heat transferred to other pattern wirings 137 and vias 138 passes through the side terminals 134. It is transmitted to the core 151. Part of heat can be dissipated through the insulating core wire 161 and the core wire 151.

  In order to reduce the burden on the subject, the distal end portion of the endoscope is formed to be as small as possible. For this reason, heat tends to be trapped at the distal end portion of the endoscope. When heat is trapped in the distal end portion of the endoscope, the temperature of the image sensor rises, thereby increasing the dark current included in the image signal and degrading the image quality. However, according to the present embodiment, the heat generated by the image sensor 120 is transferred to the outer graphite sheet 142 and the inner graphite sheet 154, so that the heat generated by the image sensor 120 is efficiently absorbed and efficiently dissipated. It is possible to prevent the temperature of the tip of the endoscope from reaching a predetermined temperature. And degradation of image quality can be prevented.

  In addition, the number of the built-in coaxial cables 150 and the insulated wires 160 is not limited to three, and the positional relationship between them is not limited to the illustrated one.

  The outer graphite sheet 142 may be provided inside the outer mesh line 141, and the inner graphite sheet 154 may be provided inside the inner mesh line 153.

  The first cable 140 may incorporate a multi-core cable, or may incorporate only a plurality of built-in coaxial cables 150.

  When the outer graphite sheet 142 is present, the built-in coaxial cable 150 may not have the inner graphite sheet 154, and when the built-in coaxial cable 150 has the inner graphite sheet 154, the outer graphite sheet 142 may not be present. .

  Next, the 2nd thermal radiation apparatus 200 by 2nd Embodiment is demonstrated using FIG. 4 and 5. FIG. About the same structure as 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The second heat dissipation device 200 includes a substrate 130 and a second cable 240, is stored in the casing 110 together with the image sensor 120, and is stored in the distal end portion 25 of the endoscope 20. Since the configurations of the image sensor 120, the substrate 130, and the casing 110 are the same as those in the first embodiment, description thereof is omitted.

  The second cable 240 includes a core wire 241 made of a plurality of copper wires, an insulator 242 provided around the core wire 241, a braided wire 243 provided around the insulator 242, and a braided wire 243. The graphite sheet 244 provided so as to cover the outer surface and the outer skin 245 provided so as to cover the graphite sheet 244 are provided. The insulator 242 is made of, for example, polyethylene. The braided wire 243 is also referred to as a shielding member, and is formed by braiding a conductive wire made of copper into a mesh shape, or simply winding a conductive wire. The thermal conductivity of copper is 401 W / m · k. The graphite sheet 244 is obtained by processing graphite into a sheet shape and forms a heat transfer member. The graphite sheet 244 has a thickness of 17 μm to 100 μm, the graphite sheet 244 having a thickness of 17 μm has a thermal conductivity of 1750 W / m · k, and the graphite sheet 244 having a thickness of 100 μm has a thermal conductivity of 700 W / m · k. The outer skin 245 is made of an insulator such as vinyl. The braided wire 243 and the graphite sheet 244 are in contact with each other and are thermally connected. The core wire 241 is soldered to the side terminal 134 and the braided wire 243 is soldered to the flat terminal 135.

  Next, the state of the heat dissipation device when the image sensor 120 generates heat will be described. When the image sensor 120 generates heat, the heat is transferred from the ball terminal 123 to the substrate 130 via the circular terminal 136. The heat transferred to the substrate 130 is transferred to the pattern wiring 137 and the via 138. The heat transferred to some of the pattern wirings 137 and vias 138 is transferred to the braided wire 243 and the graphite sheet 244 through the flat terminals 135. Since the graphite sheet 244 has a thermal conductivity larger than that of copper, the graphite sheet 244 can transmit more heat faster than the braided wire 243 over a wide range. That is, by providing the graphite sheet 244 outside the braided wire 243, it is possible to absorb more heat from the image sensor 120 and to dissipate it compared to the case where only the braided wire 243 is provided.

  Further, the heat transmitted to some of the pattern wirings 137 and vias 138 is transmitted to the core wire 241 through the side terminals 134. Part of the heat can be dissipated through the core wire 241.

  According to this embodiment, the same effect as that of the first embodiment is obtained.

  In this embodiment, the graphite sheet 244 may be provided inside the braided wire 243.

  Next, the 3rd heat radiating device 300 by 3rd Embodiment is demonstrated using FIG. 6 and 7. FIG. About the same structure as 1st and 2nd embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The third heat dissipation device 300 includes a substrate 130 and a third cable 340, is stored in the casing 110 together with the image sensor 120, and is stored in the distal end portion 25 of the endoscope 20. Since the configurations of the image sensor 120 and the casing 110 are the same as those in the first embodiment, description thereof is omitted.

  The third cable 340 is formed by wrapping three twisted pair cables 350 and three insulated wires 160 with an outer braided wire 141, an outer graphite sheet 142, and an outer skin 143. The configurations of the insulated wire 160, the outer mesh wire 141, the outer graphite sheet 142, and the outer skin 143 are the same as those in the first embodiment, and thus description thereof is omitted.

  The twisted pair cable 350 includes two covered core wires 370 twisted together, an inner mesh wire 353 provided around the two covered core wires 370, and an inner graphite sheet 354 provided so as to cover the inner mesh wire 353. And an inner skin 355 provided so as to cover the inner graphite sheet 354. The covered core wire 370 includes a core wire 371 and an insulator 372. The core wire 371 is made of a plurality of copper wires, and the insulator 372 is made of, for example, polyethylene. Two coated core wires are wrapped by the inner mesh wire 353, the inner graphite sheet 354, and the inner skin 355. The configurations of the inner mesh braid 353, the inner graphite sheet 354, and the inner outer skin 355 are the same as those in the first embodiment, and a description thereof will be omitted.

  The three twisted pair cables 350 are alternately arranged with the three insulated wires 160 to form a cylindrical shape, and the outer mesh wire 141 covers the periphery of the cylinder. Then, the outer graphite sheet 142 covers the periphery of the outer mesh line 141, and the outer skin 143 covers the periphery of the outer graphite sheet 142. The outer braided wire 141 and the outer graphite sheet 142 are in contact with each other and are thermally connected.

  Next, the state of the third heat dissipation device 300 when the image sensor 120 generates heat will be described. When the image sensor 120 generates heat, the heat is transferred from the ball terminal 123 to the substrate 130 via the circular terminal 136. The heat transferred to the substrate 130 is transferred to the support portion 112, the pattern wiring 137, and the via 138. The heat transferred to the support 112 is transferred to the outer braided wire 141 and the outer graphite sheet 142 via the outer shell 111. On the other hand, the heat transmitted to a part of the pattern wiring 137 and the via 138 is transmitted to the inner mesh line 353 and the inner graphite sheet 354 through the flat terminal 135. Since the graphite sheet has a thermal conductivity larger than that of copper, more heat can be transmitted to the wide area faster than the outer mesh line 141 and the inner mesh line 353. That is, by providing the outer graphite sheet 142 and the inner graphite sheet 354 on the outer side of the outer mesh line 141 and the inner mesh line 353, respectively, compared with the case where only the outer mesh line 141 and the inner mesh line 353 are provided. Thus, more heat can be absorbed from the image sensor 120 and can be dissipated.

  Further, the heat transferred to some of the pattern wirings 137 and vias 138 is transferred to the insulating core wires 161 via the plane terminals 135, and the heat transferred to other pattern wirings 137 and vias 138 passes through the side terminals 134. It is transmitted to the coated core wire 371. Part of heat can be dissipated through the insulating core wire 161 and the coated core wire 371.

  According to this embodiment, the same effect as that of the first embodiment is obtained.

  The number of twisted pair cables 350 and insulated wires 160 is not limited to three, and the positional relationship between them is not limited to that shown in the figure.

  The outer graphite sheet 142 may be provided inside the outer mesh line 141, and the inner graphite sheet 354 may be provided inside the inner mesh line 353.

  The third cable 340 may include a multicore cable or may include only a plurality of twisted pair cables 350.

  The number of twisted pair cables 350 built in the third cable 340 is not limited to three.

  When the outer graphite sheet 142 is provided, the twisted pair cable 350 may not include the inner graphite sheet 354. When the inner graphite sheet 354 is provided, the outer graphite sheet 142 may not be provided.

  Next, the 4th heat radiating device 400 by 4th Embodiment is demonstrated using FIG. 8 and 9. FIG. The same configurations as those in the first to third embodiments are denoted by the same reference numerals and description thereof is omitted.

  The fourth heat dissipation device 400 includes a substrate 130 and a fourth cable 440, is stored in the casing 110 together with the image sensor 120, and is stored in the distal end portion 25 of the endoscope 20. Since the configurations of the image sensor 120, the substrate 130, and the casing 110 are the same as those in the first embodiment, description thereof is omitted.

  The fourth cable 440 includes two coated core wires 450 twisted together, a mesh wire 443 provided around the two coated core wires 450, and a graphite sheet 444 provided so as to cover the mesh wire 443. And an outer skin 445 provided so as to cover the graphite sheet 444. The coated core wire 450 includes a core wire 451 and an insulator 452. The core wire 451 is made of a plurality of copper wires, and the insulator 452 is made of, for example, polyethylene. Since the structure of the braided wire 443, the graphite sheet 444, and the outer skin 445 is the same as that of the first embodiment, description thereof is omitted.

  Next, the state of the heat dissipation device when the image sensor 120 generates heat will be described. When the image sensor 120 generates heat, the heat is transferred from the ball terminal 123 to the substrate 130 via the circular terminal 136. The heat transferred to the substrate 130 is transferred to the pattern wiring 137 and the via 138. The heat transferred to some of the pattern wirings 137 and the vias 138 is transferred to the braided wire 443 and the graphite sheet 444 through the flat terminals 135. Since the graphite sheet 444 has a thermal conductivity larger than that of copper, the graphite sheet 444 can transmit more heat faster than the braided wire 443 over a wide range. That is, by providing the graphite sheet 444 outside the braided wire 443, it is possible to absorb more heat from the image sensor 120 and to dissipate heat compared to the case where only the braided wire 443 is provided.

  Further, the heat transferred to some of the pattern wirings 137 and vias 138 is transferred to the core wire 451 through the side terminals 134. Part of the heat can be dissipated through the core wire 451.

  According to this embodiment, the same effect as that of the second embodiment is obtained.

  In the present embodiment, the graphite sheet 444 may be provided inside the braided wire 443.

  In any of the embodiments, the casing 110 may not be cylindrical.

  In any of the embodiments, the material of the substrate is not limited to the above-described material, and may be any material suitable for each characteristic. And the shape of a board | substrate is not limited to a rectangular parallelepiped.

  In any of the embodiments, the first to fourth cables 140 to 440 may include only a multicore cable such as a twisted pair cable instead of the coaxial cable. It may be built-in.

  The outer graphite sheet 142, the inner graphite sheet 154, the graphite sheet 244, the inner graphite sheet 354, and the graphite sheet 444 may be made of a carbon-based material. For example, carbon fibers or carbon fibers are woven into a sheet shape. It may be.

  In any of the embodiments, the graphite sheet is provided not only on the outer periphery of the braided wire, but also on the outer periphery, the inner periphery, the outer periphery and the inner periphery, the entire outer periphery, the inner periphery, the outer periphery, and the inner periphery. May be.

  An apparatus provided with the first to fourth heat radiation apparatuses 100-400 is not limited to an endoscope.

  In any embodiment, the image sensor 120 may not be a CMOS, and may be a solid-state image sensor such as a CCD.

DESCRIPTION OF SYMBOLS 100 1st thermal radiation apparatus 110 Casing 111 Outer shell 112 Support part 113 Fixing hole 120 Imaging element 121 Imaging surface 122 Terminal surface 123 Ball-shaped terminal 130 Substrate 131 Mounting surface 132 Cable surface 133 Side surface 134 Side terminal 135 Planar terminal 136 Circular terminal 137 Pattern wiring 138 Via 140 First cable 141 Outer mesh assembly wire 142 Outer graphite sheet 143 Outer outer sheath 150 Built-in coaxial cable 151 Core wire 152 Insulator 153 Inner mesh assembly wire 154 Inner graphite sheet 155 Inner outer sheath 160 Insulated wire 161 Insulated core wire 162 Insulator 170 Resin

Claims (7)

An endoscope that dissipates heat generated by an image sensor,
A substrate on which an image sensor is mounted;
A wiring member provided on the substrate and electrically and thermally connected to the imaging device;
With coaxial cable,
The coaxial cable is
A core wire for transmitting an electrical signal from the substrate;
An insulator provided on an outer periphery of the core wire and covering the core wire;
A first shielding member provided on an outer periphery of the insulator, covering the insulator, and electrically and thermally connected to the wiring member;
A first conductor having a thermal conductivity higher than that of copper, which is provided so as to be in contact with the outer peripheral surface of the first shielding member, covers the first shielding member, and is thermally connected to the wiring member. An endoscope having a heat transfer member.   The endoscope according to claim 1, wherein the substrate is attached to a terminal surface provided on the back surface of the imaging surface of the image sensor. A second shielding member provided in contact with the plurality of coaxial cables;
The endoscope according to claim 1, further comprising: a second heat transfer member provided on an outer periphery of the second shielding member.   The endoscope according to claim 3, wherein the second shielding member is provided on an outer periphery of the plurality of coaxial cables.   The endoscope according to claim 3 or 4, wherein the second heat transfer member is thermally connected to an outer shell that houses the substrate.   The endoscope according to claim 1, wherein the first heat transfer member is made of a graphite sheet. It said second heat transfer member is an endoscope according to claim 3 consisting of a graphite sheet provided over the entire circumference of the outer periphery of the second shielding member.

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