JP2006093471A - Shield case, high-frequency circuit board, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-frequency circuit board in which a shield frame joined to a wiring board is easily removed, and a high-frequency circuit is easily and rapidly repaired and exchanged. <P>SOLUTION: The high-frequency circuit board 1 comprises: a wiring board 2, a plurality of electronic components 3 mounted on the wiring board 2; a shield frame 4 joined onto the wiring board 2 so that a high-frequency circuit occupation region A including a region for mounting the plurality of electronic components 3 is surrounded; and a shield cover 5 that is fitted to the shield frame 4 collectively and blocks the plurality of electronic components 3. The plane shape of the shield frame 4 is in an L shape. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a shield case that shields electromagnetic noise of a high-frequency circuit unit mounted on a wiring board, a high-frequency circuit board that includes the shield case, and an electronic device that includes the high-frequency circuit board.

For example, in a high-frequency circuit board such as a PC card type wireless terminal, a plurality of high-frequency circuit units (electronic devices) are mounted in order to transmit and receive electrical signals wirelessly. These high-frequency circuit units are closed by a shield frame and a shield cover soldered to the wiring board (see, for example, Patent Document 1). Specifically, the shield frame has an integral shape surrounding a region where the high-frequency circuit portion is mounted on the wiring board, and has a structure in which a flange portion rises along the periphery. And the high frequency circuit part is obstruct | occluded by fitting a shield cover to this flange part. For this reason, electromagnetic noise generated from the high-frequency circuit section is absorbed by the shield case composed of the shield frame and shield cover, so that the electromagnetic noise leaks to other circuit sections and the outside, and conversely, noise from outside Prevents picking up.
JP2003-133777 (3rd page, FIG. 1)

  However, in the high frequency circuit board in which the shield structure is provided on the wiring board as described above, it is necessary to prevent leakage of electromagnetic noise generated from a plurality of electronic components (high frequency circuit portions).

  In the above-described high-frequency circuit board, a solder paste is printed on the wiring board in a predetermined pattern, and then BGA (Ball Grid Array) structure electronic components and a shield frame are mounted on the wiring board, and a batch using a reflow device. It is manufactured by soldering by heating. For this reason, the operation test of the high-frequency circuit board on which the electronic component is mounted is performed in a state where the shield frame is mounted. Therefore, when a defect is detected in the electronic component on the wiring board after the operation test, it is necessary to remove the entire shield frame, remove the electronic component from the wiring board, and rejoin the replacement part to the wiring board.

  In order to replace the electronic component after the operation test, a rework apparatus 100 as shown in FIG. 13 is used. The rework apparatus 100 includes a duct 101 for blowing hot air to the electronic component 102 and a suction nozzle 103 provided in the duct 101 for sucking the electronic component 102. As shown in FIG. 13, the electronic component 102 is bonded to the wiring board 105 via the solder bumps 104. However, in the wiring board 105, as shown in FIG. 13, since the shield frame 106 is disposed close to the side of at least one side of the electronic component 102, the shield frame 106 interferes. The duct 101 of the rework apparatus 100 could not be brought into contact with the wiring board 105. For this reason, hot air cannot be blown only on the joint part of the specific electronic component 102, and it can reach other electronic components, or the suction nozzle 103 cannot contact the electronic component 102 and suck the electronic component 102. There was an inconvenience that it was not possible. For this reason, it was necessary to peel off the shield frame 106 from the wiring board 105 before using the rework apparatus 100.

  14 to 16 show a conventional procedure for removing the electronic component 102. The shield frame 106 is electrically connected to the wiring board 105 at a plurality of soldering portions (not shown) in order to prevent leakage of electromagnetic noise. For this reason, all the soldering portions in the shield frame 106 are melted by using a heating tool such as a soldering iron, and the shield frame 106 is removed from the wiring board 105. When there are a plurality of soldered portions, the shield frame 106 is cut as necessary to perform the removal operation. After the shield frame 106 is removed in this way, the electronic component 102 is peeled off from the wiring board 105 using the rework apparatus 100 as shown in FIGS. 15 and 16. As shown in FIG. 15, after the shield frame 106 is removed, a margin dimension o for arranging the duct 101 around the electronic component 102 can be secured.

  The above-described removal work of the shield frame 106 is complicated and time-consuming because it is necessary to remove the whole from the wiring board 105 in a lump or to divide and remove it. For this reason, there has been a problem that it is expensive to repair and replace electronic components. Further, in the removal operation of the shield frame 106, it is necessary to heat the parts other than the electronic component 102 to be replaced in order to melt all the soldered portions, and thermal damage is caused to the electronic parts and the wiring board 105 in other parts. There was a risk of giving.

  Accordingly, the present invention has been made to solve the above-described problems, and a first object is to simplify the removal work of the shield frame bonded to the wiring board, and to easily repair and replace the high-frequency circuit section. Another object of the present invention is to provide a high-frequency circuit board, a shield case, and an electronic device that can be quickly performed.

  A second object of the present invention is to provide a high-frequency circuit board, a shield case, and an electronic device that can easily hold the shield frame when the shield frame is mounted on a wiring board.

  A third object of the present invention is to provide a high-frequency circuit board, a shield case, and an electronic device that have a high effect of preventing leakage of electromagnetic noise generated from a high-frequency circuit unit mounted on a wiring board.

  A first feature of the present invention is a shield case attached to a wiring board on which a plurality of high-frequency circuit units are mounted, and is arranged along a periphery of a high-frequency circuit occupation region that encompasses a region on which a plurality of high-frequency circuit units are mounted. In this way, a plurality of shield frames standing independently of each other and a side plate portion perpendicular to the cover body are formed around the peripheral edge portion of the plate-like cover body so that the side plate portion includes a plurality of shields. A shield cover that fits over the entire frame and closes the plurality of high-frequency circuit portions, and the shield frame has a bent portion at an intermediate portion in a planar shape, and one shield at a corner portion of the high-frequency circuit occupation region The frame is to be placed.

  A second feature of the present invention is a high-frequency circuit board including a high-frequency circuit unit, which includes a wiring board on which a plurality of high-frequency circuit parts are mounted, and a region in which the plurality of high-frequency circuit parts are mounted on the wiring board. A plurality of shield frames erected independently of each other so as to line up along the periphery of the high-frequency circuit occupation area, and a side plate portion that makes a right angle to the cover body circulates along the peripheral edge portion of the plate-like cover body And a shield cover that is fitted to the entirety of the plurality of shield frames to close the plurality of high-frequency circuit portions, and the planar shape of the shield frame is L-shaped.

  Furthermore, a third feature of the present invention is an electronic device, which is a wiring board on which a plurality of high-frequency circuit units are mounted, and a periphery of a high-frequency circuit occupation region that includes a region on the wiring board on which a plurality of high-frequency circuit units are mounted. A plurality of shield frames standing independently of each other so as to be lined up along the side plate, and a side plate portion that is formed so as to circulate along a peripheral edge portion of the plate-like cover main body and perpendicular to the cover main body. A shield cover that fits all over the plurality of shield frames and closes the plurality of high-frequency circuit portions, and the shield frame includes a high-frequency circuit board having a bent portion at an intermediate portion in a planar shape. It is to prepare.

  According to the present invention, a shield case, a high-frequency circuit board, and an electronic device that can efficiently repair and replace a high-frequency circuit unit are obtained.

  Hereinafter, details of a shield case, a high-frequency circuit board, and an electronic device according to embodiments of the present invention will be described with reference to the drawings.

(Configuration of shield case and high-frequency circuit board)
First, the configurations of the shield case and the high-frequency circuit board according to the present embodiment will be described with reference to FIGS.

  As shown in FIG. 1, the high-frequency circuit board 1 includes a wiring board 2, a plurality of electronic components 3 as high-frequency circuit parts mounted on the wiring board 2, and a region in which the plurality of electronic components 3 are mounted. A plurality of shield frames 4 joined so as to be electrically connected to the wiring board 2 independently of each other so as to surround a comprehensive high-frequency circuit occupation area A, and all of the shield frames 4 are fitted together. And a shield cover 5 that closes the plurality of electronic components 3.

  The high-frequency circuit board 1 described in the present embodiment refers to a circuit board that is configured by mounting an electronic component 3, a shield case 6, and an electronic component that is not another high-frequency circuit unit on a wiring board 2.

  The electronic component 3 as the above-described high-frequency circuit unit used in the present embodiment is, for example, an electronic component having a BGA (Ball Grid Array) structure having a solder bump on the lower surface. A predetermined wiring pattern (not shown) is formed on the wiring board 2, and the electronic component 3 is joined to the appropriate wiring pattern by soldering. Although not shown, various chip components such as a power supply IC, an AD converter and an IC as a DA converter, a CPU, and a memory are mounted on the wiring board 2 in addition to a plurality of electronic components 3 as a high-frequency circuit unit. Yes.

  Both the shield frame 4 and the shield cover 5 described above are formed of a metal having good conductivity. A plurality of shield frames 4 and one shield cover 5 constitute a shield case 6.

  As shown in FIGS. 1-6, the shield frame 4 has a bending part in the intermediate part in planar shape. That is, the shield frame 4 is L-shaped in plan view, and as shown in FIGS. 1 and 2, the wiring board 2 surrounds the high-frequency circuit occupation area A including the area where the plurality of electronic components 3 are mounted. It is joined to the top by soldering.

  One shield frame 4 is assigned to one corner of the high-frequency circuit occupation area A. For this reason, in the shield frame 4, the lengths of the flange portions (described later) 41 on both sides sandwiching the corner portions are set in advance according to the shape and dimensions of the high-frequency circuit occupation region A. Specifically, as shown in FIG. 1 and FIG. 2, the length of the flange portion 41 that sandwiches the corner portion is set to the side surface portion of one electronic component 3 that is disposed in the vicinity of the corner portion of the high-frequency circuit occupation region A. Is set to be substantially equal to the length of the plurality of electronic components 3 or facing each other over the side surfaces of the plurality of electronic components 3. Therefore, as will be described later, when the electronic component 3 is replaced, the electronic component 3 can be replaced only by removing one or two shield frames 4 surrounding (side) the electronic component 3. Dimensioned to be possible.

  In the present embodiment, according to the mounting accuracy of the mounting device, the shield frames 4 adjacent to each other at the time of mounting are arranged on the wiring board 2 so as not to contact each other (about 0.2 mm). The shield frame 4 is electrically connected to the wiring board 2 by soldering the projections 43 for bonding.

  Here, the structure of the shield frame 4 will be described with reference to FIGS. 1 and 3 to 5. The shield frame 4 includes the above-described flange portion 41 disposed so as to make a right angle to the wiring substrate 2, and a parallel plate portion 42 extending from the upper edge of the flange portion 41 toward the bent inner side (one side). The parallel plate portion 42 at the bent corner portion is widely adsorbed plate portion 42A so as to bulge toward the inside of the bend. In addition, a plurality of rectangular joint protrusions 43 protruding slightly downward are formed on the lower edge of the flange portion 41 (two in this embodiment with respect to one flange portion 41). Has been. In the present embodiment, in the bent portion of the shield frame 4, the flange portion 41 is bent with respect to the parallel plate portion 42 so that the edges of the flange portions 41 on both sides come into contact with each other.

  The shield cover 5 is formed such that a side plate portion 52 that is substantially perpendicular to the cover body 51 circulates along the peripheral edge portion of a plate-like (substantially rectangular shape in the present embodiment) cover body 51. The side plate portions 52 are collectively fitted to the entire plurality of shield frames 4 so as to close the plurality of electronic components 3 in the high-frequency circuit occupation area A. As shown in FIGS. 1, 3, and 8, the side plate portion 52 has a side plate portion 52 in the width direction (a direction perpendicular to the cover body 51) at predetermined intervals along the periphery of the cover body 51. A slit 53 having substantially the same length as the width dimension is formed. 8 is a cross-sectional view taken along the line aa in FIG. As shown in FIG. 8, the interval q between the adjacent slits 53 is set to be shorter than half of the electromagnetic noise wavelength λ generated from the electronic component 3 in the high-frequency circuit occupation area A. That is, the relationship 2q <λ is established. Further, as shown in FIG. 8, the combined length r of two adjacent side plate portions 52 separated by the slit 53 is set to be shorter than the electromagnetic noise wavelength λ. That is, r <2q is set.

  Further, as shown in FIG. 7, when the shield cover 5 is fitted to the shield frame 4 in the middle portion of the side plate portion 52 of the shield cover 5 (in the direction perpendicular to the cover main body 51), A bulging portion 52A that is bent so as to bulge inward so as to come into pressure contact with the flange portion 41 of the shield frame 4 is provided along the lateral direction (a direction parallel to the periphery of the cover main body 51). ing.

(Operation of shield case)
The shield case 6 according to the present embodiment has an operation as described below.

  First, since the shield frame 4 is formed in an L shape so that one shield frame 4 corresponds to one corner of the high-frequency circuit occupation area A on the wiring board 2, one or two are provided. By removing the two shield frames 4 from the wiring board 2, it is possible to repair the electronic component 3 at a predetermined location. Specifically, it is possible to surround the electronic component 3 with a duct of a rework device that discharges hot air without removing all the shield frames 4, and the electronic component 3 without affecting the other electronic components 3 thermally. Allows removal. Further, when mounting the non-defective electronic component 3 on the wiring board 2 from which the electronic component 3 has been removed, since the shield frame 4 around the mounting area is removed, the mounting can be easily performed.

  Further, as shown in FIG. 6, the shield frame 4 has a L-shaped planar shape and is formed with a suction plate portion 42A at a corner portion as a bent portion which is an intermediate portion. When adsorbing with the adsorption nozzle 8 of the apparatus, adsorption and holding can be performed stably.

  Furthermore, since the shield frame 4 has a shape in which the flange portion 41 and the parallel plate portion 42 are bent in an L shape, the shield frame 4 has an effect of being highly rigid and difficult to deform.

  In the side plate portion 52 of the shield cover 5, as described above, the interval q between the slits 53 adjacent to each other is set to be shorter than half of the electromagnetic noise wavelength λ generated from the electronic component 3 in the high-frequency circuit occupation region A, The combined length r of the two pieces of side plate portions 52 separated by the slit 53 is set to be shorter than the electromagnetic noise wavelength λ. By the way, as shown in FIG. 8, the cavity part 7 formed between the two adjacent side plate parts 52 delimited by the slit 53 and the flange part 41 has an edge on the side where the side plate parts 52 are adjacent to each other. Becomes the maximum length r when floating from the flange portion 41. For this reason, because of the relationship r <2q and 2q <λ, the length of the cavity 7 is always smaller than the electromagnetic noise wavelength λ, so that electromagnetic noise generated from the electronic component 3 is generated between the shield cover 5 and the shield frame 4. It is possible to prevent leakage from the hollow portion 7 of the fitting portion and maintain the shielding effect.

  In addition, since the side plates 52 sandwiched between the slits 53 have spring properties due to the formation of the plurality of slits 53 in the side plate 52, the plurality of shield frames 4 are displaced in the thickness direction of the flange portion 41. Even when they are joined together, the shield cover 5 can be securely fitted to the shield frame 4.

  Furthermore, in the present embodiment, the side plate portion 52 of the shield cover 5 is formed with the bulging portion 52A that bulges inward, so that the pressure contact strength with the flange portion 41 can be maintained.

(Electronic component mounting method and replacement method on high-frequency circuit board)
Next, a method for mounting the electronic component 3 and the shield case 6 on the wiring board 2 will be described. First, a wiring board 2 in which a solder paste is printed in a predetermined pattern is prepared in advance, and an electronic component 3 having a BGA (Ball Grid Array) structure is arranged at a predetermined position on the wiring board 2 using a mounting device. Next, the shield frame 4 is mounted on the wiring board 2 by the suction nozzle 8 of the mounting device (see FIG. 6), and the electronic component 3 and the shield frame 4 are soldered by batch heating using a reflow device.

  Thereafter, the shield cover 5 may be fitted all over the flange portions 41 of the plurality of shield frames 4 to block the plurality of electronic components 3 in the high-frequency circuit occupation area A. At this time, as described above, the side plate portion 52 of the shield cover 5 is formed with the bulging portion 52A that bulges inward, so that the pressure contact strength with the flange portion 41 can be maintained.

  Such an operation test of the high-frequency circuit board 1 is performed before the shield cover 5 is fitted to the shield frame 4. Therefore, when a defect is detected in the electronic component 3 on the wiring board 2 after the operation test, it is necessary to remove the electronic component 3 from the wiring board 2 and rejoin the replacement component to the wiring board 2.

  In order to replace the electronic component 3 after the operation test, it is necessary to remove the shield frame 4 which becomes an obstacle when the rework device is applied to the electronic component 3 as shown in FIG. In the present embodiment, one or two shield frames 4 bonded to the wiring board 2 around the electronic component 3 to be replaced may be removed from the wiring board 2.

  Next, using the rework apparatus 100 having the duct 101 as shown in FIG. 15, the electronic component 3 is disposed so as to surround the suction component 103 and is brought into contact with the upper surface of the electronic component 3 for adsorption. In this state, hot air is supplied from the duct 101 to melt the solder bumps 3A of the electronic component 3 to raise the rework apparatus 100, and the electronic component 3 is removed from the wiring board 2 as shown in FIG.

  Thereafter, the non-defective electronic component 3 may be placed on the wiring board 2 by a mounting device and mounted again by a reflow device. At this time, the shield frame 4 may be mounted simultaneously with the electronic component 3 or may be soldered to the wiring board 2 after the electronic component 3 is mounted. Thus, after joining the good electronic component 3 and one or two shield frames 4 around it to the wiring board 2, the entire flange portion 41 of the shield frame 4 is collectively fitted with the shield cover 5. Thus, the replacement of the electronic component 3 is completed, and the high-frequency circuit board 1 that performs normal operation can be manufactured.

  The shield case 6 and the high-frequency circuit board 1 have been described above. In the present embodiment, the high-frequency circuit occupation area A that includes the area in which the electronic component 3 is mounted by combining the L-shaped shield frame 4 in plan view. Since only the shield frame 4 provided along the region where the specific electronic component 3 is mounted needs to be removed from the wiring board 2, the electronic component 3 mounted at other locations is affected (heat The electronic component 3 can be efficiently repaired and replaced without causing any damage.

  Further, according to the present embodiment, by forming the adsorbed plate portion 42A toward the bent inner side at the upper edge of the corner portion of the shield frame 4 bent in an L shape, the intermediate portion of the shield frame 4 is For example, it can be held by a suction jig such as the suction nozzle 8 of the mount device, and can be mounted on the wiring board 2 stably and reliably.

(Configuration of electronic equipment)
FIG. 10 shows an electronic device 10 according to the present invention. The electronic device 10 is used as a PC card type wireless terminal.

  As shown in FIG. 10, the electronic device 10 is one in which the above-described high-frequency circuit board 1 is built in a card-shaped casing 11. An antenna 12 is provided at one end of the casing 11, and a connector for connection 13 is provided at the other end. Since the configuration of the high-frequency circuit board 1 built in the electronic device 10 is the same as that of the high-frequency circuit board 1 of the above embodiment, the description thereof is omitted.

  The electronic device 10 according to the present embodiment can repair and replace the electronic component 3 constituting the high-frequency circuit unit provided in the electronic device 10 at low cost and efficiently. Thermal influence can be greatly suppressed, and performance can be stabilized.

(Other embodiments)
It should not be understood that the descriptions and drawings which form part of the disclosure of the above-described embodiments limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, in the above-described embodiments, the present invention has been described by applying it to the electronic device 10 as a PC card type wireless terminal. However, the present invention can be applied to all electronic devices including other high-frequency circuit units. it can.

  Further, in the high-frequency circuit board 1 and the shield case 6 according to the above-described embodiment, all of the plurality of shield frames 4 have a planar L shape, but a plane straight line is formed between the L-shaped shield frames 4. It is also possible to appropriately adopt a configuration in which a shield frame formed in a shape is interposed.

  Further, in the shield frame 4 constituting the shield case 6 according to the above-described embodiment, as shown in FIGS. 11 and 12, a notch having a predetermined width is formed in the intermediate portion of the parallel plate portion 42 on one side across the corner portion. The portion 44 may be formed. The cutout portion 44 is formed so as to reach the flange portion 41, and the shield frame 4 can be easily divided at this portion. In addition, you may form this notch part 44 in the parallel plate part 42 and the flange part 41 of the both sides which pinch | interpose a corner | angular part.

1 is an exploded perspective view showing a high-frequency circuit board according to an embodiment of the present invention. It is a top view which shows the high frequency circuit board which concerns on embodiment of this invention. It is a principal part perspective view which shows the high frequency circuit board which concerns on embodiment of this invention. It is the perspective view which looked at the shield frame of the shield case which concerns on embodiment of this invention from the upper side. It is the perspective view which looked at the shield frame of the shield case concerning an embodiment of the invention from the lower side. It is a perspective view which shows the state which mounts the shield frame of the shield case which concerns on embodiment of this invention. It is principal part sectional drawing of the high frequency circuit board which concerns on embodiment of this invention. It is aa sectional drawing of FIG. It is an exploded perspective view of the high frequency circuit board concerning an embodiment of the invention. It is a perspective view of the electronic device which concerns on embodiment of this invention. It is the perspective view which looked at the shield frame which comprises the shield case which concerns on other embodiment of this invention from the upper side. It is the perspective view which looked at the shield frame which comprises the shield case which concerns on other embodiment of this invention from the lower side. It is principal part sectional drawing which shows the case where the electronic component is replaced | exchanged in the conventional high frequency circuit board. It is a perspective view which shows the state which removes a shield frame in the conventional high frequency circuit board. It is principal part sectional drawing which shows the removal process of the electronic component in a high frequency circuit board. It is a disassembled perspective view which shows the removal process of the electronic component in the conventional high frequency circuit board.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... High frequency circuit board, 2 ... Wiring board, 3 ... Electronic component, 3A ... Solder bump, 4 ... Shield frame, 5 ... Shield cover, 6 ... Shield case, 8 ... Adsorption nozzle, 10 ... Electronic equipment, 41 ... Flange part 42 ... Parallel plate portion, 42A ... Adsorbed plate portion, 43 ... Convex projection, 51 ... Cover body, 52 ... Side plate portion, 53 ... Slit.

Claims (7)

A shield case attached to a wiring board on which a plurality of high-frequency circuit units are mounted,
A plurality of shield frames erected independently of each other so as to be arranged along the periphery of the high-frequency circuit occupation region that encompasses the region where the plurality of high-frequency circuit portions are mounted, and along the peripheral portion of the plate-like cover body A side cover part that is perpendicular to the cover body is formed so as to circulate, and the side plate part is fitted to the entirety of the plurality of shield frames to close the plurality of high-frequency circuit parts, and
The shield frame has a bent portion at an intermediate portion in a planar shape, and one of the shield frames is arranged so that the bent portion corresponds to each corner of the high-frequency circuit occupation region. Shield case.   The suction plate portion having an area that can be sucked by a suction jig is formed on the upper edge of the bent portion of the shield frame. Shield case.   The side plate portion is formed with a plurality of cutout portions along a direction perpendicular to the cover body, and the interval between the cutout portions adjacent to each other is half of the electromagnetic noise wavelength generated from the high frequency circuit portion. The shield case according to claim 1 or 2, wherein the shield case is set shorter. A wiring board on which a plurality of high-frequency circuit units are mounted;
A plurality of shield frames erected independently of each other so as to be arranged along a periphery of a high-frequency circuit occupation region including a region where the plurality of high-frequency circuit units are mounted on the wiring board;
A side plate portion perpendicular to the cover body is formed to circulate along a peripheral edge portion of the plate-shaped cover body, and the side plate portion is fitted to the entirety of the plurality of shield frames to thereby form the plurality of high frequency circuit portions. A shield cover for closing
The high frequency circuit board according to claim 1, wherein the shield frame has a bent portion at an intermediate portion in a planar shape.   In the side plate portion, a notch portion along a direction perpendicular to the cover body is intermittently formed along a peripheral edge portion of the cover body, and an interval between the notch portions adjacent to each other is determined by the high frequency circuit. 5. The high frequency circuit board according to claim 4, wherein the frequency is shorter than half of the electromagnetic noise wavelength radiated from the portion.   The shield frame is formed with an adsorbed plate portion having an area that can be adsorbed by an adsorption jig, extending toward the inside of the high-frequency circuit occupation region at the upper edge of the bent portion. The high-frequency circuit board according to claim 4 or 5.   An electronic apparatus comprising the high-frequency circuit board according to any one of claims 4 to 6.

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