JP2007109846A - Chip resistor and method of manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the surge resistance of the resistance film in the state of securing the strength of the soldering part by the terminal electrode; in a chip resistor which comprises a rectangular insulating substrate 2, a resistance film 5 formed so as to extend in a longitudinal direction on the upper surface of this insulating substrate, a pair of upper surface electrodes 3 and 4 formed in the upper surface of the insulating substrate, and a pair of terminal electrodes 6 and 7 formed in two sides of the insulating substrate. <P>SOLUTION: Each upper surface electrode is formed in an L-shape in plan view so as to be composed of first portions 3a and 4a prolonged along two long sides 2a and 2b of an insulating substrate, and a second portions 3b and 4b prolonged along two short sides 2c and 2d. Both ends of the resistance film are connected to the second portions in the respective upper surface electrodes, and furthermore, the respective terminal electrodes may be connected to the two long sides in the insulating substrate, and to the first portions in the respective upper surface electrodes. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a chip resistor excellent in surge resistance and a manufacturing method thereof.

  In general, in a chip resistor, a resistive film is formed on the upper surface of an insulating substrate configured in a rectangular shape in plan view so as to extend in the longitudinal direction of the rectangle. A terminal electrode for soldering is formed on each of the short side surfaces so that the terminal electrode is electrically connected to both ends of the resistance film via an upper surface electrode formed on the upper surface of the insulating substrate. As is well known, the two terminal electrodes are configured to be soldered to a printed circuit board or the like.

  In this well-known chip resistor, the thermal expansion / contraction in the insulating substrate due to the heat generation of the resistive film is large in the longitudinal direction of the rectangle, but the terminals on the short side surfaces at both ends in the longitudinal direction of the rectangle. By providing electrodes and soldering mounting with both terminal electrodes, the thermal stress due to the large thermal expansion / contraction repeatedly acts on the soldered portions with both terminal electrodes. In addition, since the soldering area is small, there has been a problem that there is a high possibility that the soldering will be removed at this soldering portion.

  Therefore, in Patent Document 1 as the prior art, as described above, the resistive film is formed on the upper surface of the insulating substrate configured to be rectangular in plan view so as to extend in a direction perpendicular to the longitudinal direction of the rectangle. On the other hand, terminal electrodes for soldering to both ends of the resistance film are formed so as to extend over substantially the entire length of the long side surface on the long side surfaces at both ends of the insulating substrate in the direction perpendicular to the longitudinal direction of the rectangle. A chip resistor is proposed.

According to this prior art configuration, the thermal expansion / contraction of the insulating substrate in the direction perpendicular to the longitudinal direction of the rectangle is smaller than the thermal expansion / contraction in the longitudinal direction of the rectangle. Since the soldering area is greatly increased by forming the terminal electrode on the side surface of the long side, it is possible to reliably reduce the possibility that the soldering will be detached from the soldered portion.
JP-A-11-111505

  However, in the above prior art, the direction in which the wide resistive film extends is perpendicular to the longitudinal direction of the rectangle, so that the length of the path through which current flows in the resistive film is rectangular. This is shorter than the case of extending in the longitudinal direction of the film, so that the surge resistance of the resistive film is low. In other words, the surge resistance cannot be improved.

  Further, in the prior art, when the trimming groove extending in the width direction is formed in the resistance film so that the resistance value in the resistance film is adjusted to a predetermined value, the trimming groove The length of the film in the wide direction must be engraved or the number of trimming grooves must be increased, and this requires a long time. This increases the cost required for engraving the trimming grooves. It was also a problem to invite.

  An object of the present invention is to provide a chip resistor that solves these problems and a method of manufacturing the same.

In order to achieve this technical problem, a chip resistor according to the present invention is as described in claim 1.
“Insulating substrate having a rectangular shape in plan view, a resistance film formed on the upper surface of the insulating substrate so as to extend in the longitudinal direction of the rectangle, a pair of upper surface electrodes formed on the upper surface of the insulating substrate, In a chip resistor comprising a pair of terminal electrodes formed so as to be electrically connected to the upper surface electrode on each of two side surfaces parallel to each other,
A first portion of each of the upper surface electrodes, the first portion extending along one of the long side surfaces adjacent to one of the two long side surfaces of the rectangle of the insulating substrate; The rectangular shape of the insulating substrate is formed in an L shape in plan view so as to comprise a second portion extending along one short side surface adjacent to one short side surface of the two short side surfaces, The first upper electrode of each of the upper surface electrodes is adjacent to the other long side surface of the two long side surfaces of the rectangle of the insulating substrate and extends along the other long side surface; One of the two short side surfaces in the rectangle of the substrate is formed in an L shape in plan view so as to be composed of a second portion extending along the other short side surface adjacent to the other short side surface. , Both ends of the resistive film are connected to the one upper surface electrode. And the second portion of the other upper surface electrode is electrically connected to the second portion, and one terminal electrode of the terminal electrodes is disposed on one longitudinal side surface of the insulating substrate on the one upper surface. It is formed so as to be electrically connected to the first portion of the electrode, and the other terminal electrode of the terminal electrodes is electrically connected to the other longitudinal side surface of the insulating substrate and to the first portion of the other upper surface electrode. It is formed so as to connect to. "
It is characterized by that.

The chip resistor according to the present invention is as described in claim 2,
“In the first aspect of the present invention, a portion between one end of the resistive film connected to the second portion of the one upper surface electrode and the other end connected to the second portion of the other upper surface electrode is , It is formed in a zigzag fold. "
It is characterized by that.

The chip resistor according to the present invention is as described in claim 3,
“In the second aspect of the present invention, each of the one end connected to the second portion of the one upper surface electrode and the other end connected to the second portion of the other upper surface electrode of the resistance film has a narrow width. Is formed in the part. "
It is characterized by that.

The chip resistor according to the present invention is as described in claim 4,
“In the third aspect of the present invention, the narrow portion at one end and the other end of the resistance film is integrally formed with an extension portion that extends in the same direction as the second portion of each upper surface electrode and is overlapped with the second portion. I have. "
It is characterized by that.

The chip resistor according to the present invention is as described in claim 5,
“In any one of claims 1 to 4, the length dimension along the long side surface in the first part of either one or both of the upper surface electrodes is the length dimension on the long side surface. The trimming groove for the resistance film is provided in the shortened portion. "
It is characterized by that.

Next, the manufacturing method according to the present invention is as described in claim 6.
“A step of forming a resistive film on the upper surface of an insulating substrate that is rectangular in plan view, extending a longitudinal direction of the rectangle; a step of forming a pair of upper surface electrodes on the upper surface of the insulating substrate; Forming a terminal electrode on each of two parallel side surfaces, and a method of manufacturing a chip resistor,
The step of forming each upper surface electrode includes the step of forming one upper surface electrode of each of the upper surface electrodes adjacent to one long side surface of the two long side surfaces of the rectangle of the insulating substrate. And a second portion extending along one short side surface adjacent to one short side surface of the two short side surfaces in the rectangle of the insulating substrate. The other upper side electrode is formed adjacent to the other long side surface of the two long side surfaces in the rectangle of the insulating substrate. And a second portion extending along the other short side surface adjacent to the other short side surface of the two short side surfaces of the rectangle of the insulating substrate. It is a process of forming an L shape visually.
The step of forming the resistive film is a step of forming both ends of the resistive film so as to be electrically connected to the second portion of each upper surface electrode;
The step of forming each terminal electrode includes electrically connecting one of the terminal electrodes to the first portion of the one upper surface electrode and the first portion of the other upper electrode of the other terminal electrode. It is a process of forming so as to be connected. "
It is characterized by that.

Moreover, the manufacturing method in the present invention is as described in claim 7,
“The step of forming each upper surface electrode according to claim 6, wherein the step of forming each upper surface electrode has a length dimension along the long side surface in the first portion of either one or both of the upper surface electrodes, It is a process that is formed shorter than the length on the side.
Before the step of forming each terminal electrode, a step of forming a trimming groove in a portion of the resistive film where the first portion is not present outside in a plan view is provided. "
It is characterized by that.

  With the configuration described in claim 1, soldering when mounting on a printed circuit board or the like is performed on the terminal electrodes formed on the two long side surfaces of the rectangular insulating substrate. The area can be increased, and the thermal stress acting on the soldering portion due to thermal expansion / contraction can be reduced, so that it is possible to reliably reduce the possibility that the soldering will be detached from the soldering portion.

  On the other hand, the resistance film is formed so as to extend in the longitudinal direction of the rectangle in the insulating substrate, so that the length of the current path in the resistance film is set in a direction perpendicular to the longitudinal direction of the rectangle. Since it can be increased as compared with the case where it is formed to extend, the surge resistance can be improved, and the length of the trimming groove formed in the resistance film is shortened by the length of the current path in the resistance film, Since the number of trimming grooves can be reduced, the cost required to cut the trimming grooves can be reduced.

  In addition, since the current path in the resistance film can be remarkably increased by forming the resistance film in a zigzag shape as described in claim 2, surge resistance can be greatly improved. In the case where the film is formed in a zigzag shape, the current path becomes longer by making the both ends narrower as described in claim 3, so that the surge resistance can be further improved. Can do.

  By the way, when the resistance film is formed in a zigzag shape having narrow portions at both ends as described above, the resistance film and both upper surface electrodes are provided on the upper surface of the insulating substrate in order to reduce costs. When both the resistance film and both upper surface electrodes are formed by screen printing, there is a printing misalignment between them. The overlapping connection area between the second portion of the upper surface electrode and the upper surface electrode is likely to decrease due to the printing displacement in the longitudinal direction of the resistance film among the printing displacement, and the resistance film passes through the upper surface electrode. Therefore, the overload characteristic (STOL evaluation) of the chip resistor is deteriorated.

  For this, it is proposed that the configuration described in claim 4 be adopted, and by this configuration, the narrow portion at both ends of the resistance film and the second portion at both upper surface electrodes are provided. Can be increased by the integral extension of the narrow width portion regardless of printing displacement in the longitudinal direction of the resistive film. Since heat dissipation can be promoted, the overload characteristics of the chip resistor can be improved reliably.

  In particular, when the trimming groove for adjusting the resistance value is engraved in a part of the resistance film, the first portion of each upper surface electrode is the trimming groove. In other words, the trimming groove can be engraved in the resistance film without traversing the first portion of the upper surface electrode, so that the trimming groove is engraved. There is an advantage that the cost can be reduced.

  Further, according to the manufacturing method of the present invention, a chip resistor having the above-described function can be manufactured at a low cost.

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

  1 to 3 show a chip resistor according to a first embodiment of the present invention.

  The chip resistor 1 according to the first embodiment includes at least an insulating substrate 2 configured as a rectangular chip type having a long side L and a short side W in a plan view with a heat-resistant insulator such as ceramic. A portion of the upper surface of the insulating substrate 2 between the pair of upper surface electrodes 3 and 4 formed by screen printing on both the left and right sides in the longitudinal direction of the rectangle and the upper surface of the insulating substrate 2 between the upper surface electrodes 3 and 4. Further, the resistive film 5 formed by screen printing so as to extend in the longitudinal direction of the rectangle and the two long side surfaces 2a and 2b in the rectangle of the insulating substrate 2 extend over the entire length of the long side surfaces 2a and 2b. The soldering terminal electrodes 6 and 7 and the lower surface of the insulating substrate 2 are adjacent to the two long side surfaces 2a and 2b so as to extend along the two long side surfaces 2a and 2b. Scree A pair of lower surface electrodes 8 and 9 formed by printing and a cover coat 10 made of glass or synthetic resin formed by screen printing so as to cover the entire resistance film 5 on the upper surface of the insulating substrate 2. Yes.

  One upper electrode 3 of the upper electrodes 3 and 4 is adjacent to one long side surface 2a of the two long side surfaces 2a and 2b in the rectangle of the insulating substrate 2, and this one long side surface 2a. A second portion extending along one short side surface 2c adjacent to one short side surface 2c out of the two short side surfaces 2c, 2d of the rectangle of the insulating substrate 2; The portion 3b is formed in an L shape in plan view.

  The other upper surface electrode 4 of the upper surface electrodes 3 and 4 is adjacent to the other long side surface 2b of the two long side surfaces 2a and 2b in the rectangle of the insulating substrate 2, and this one long side surface 2b. And a second portion extending along the other short side surface 2d adjacent to the other short side surface 2d of the two short side surfaces 2c, 2d of the rectangle of the insulating substrate 2. The portion 4b is formed in an L shape in plan view.

  In this case, the length dimension L1 along the long side surfaces 2a and 2b in the first portions 3a and 4a of the upper surface electrodes 3 and 4 is made shorter than the length dimension L on the long side surfaces 2a and 2b. ing.

  The resistance film 5 is integrally provided with narrow width portions 5a and 5b that are overlapped and connected to the second portions 3b and 4b of the upper surface electrodes 3 and 4 at both ends, and between the narrow width portions 5a and 5b. Of the plurality of intrusion grooves 5c formed alternately from the left and right sides during screen printing, and the resistance film 5, the first portions 3a, 4a of the upper surface electrodes 3, 4 on the outer side in plan view. A trimming groove 5d carved in a portion having no gap is formed in a folded shape.

  One terminal electrode 6 of the both terminal electrodes 6, 7 is a first portion 3 a of one upper surface electrode 3 of the upper surface electrodes 3, 4 and one of the lower surface electrodes 8, 9. The other terminal electrode 7 is formed so as to partially overlap and connect to both the lower surface electrode 8, and the other terminal electrode 7 includes the first portion 4 a of the upper surface electrode 4 of the upper surface electrodes 3, 4, and the respective lower surface electrodes. 8 and 9 are formed so as to partially overlap and connect to both of the other lower surface electrode 9.

  Although not shown, on the surface of each of the upper surface electrodes 3, 4 not covered with the cover coat 10, the surfaces of the terminal electrodes 6, 7, and the surfaces of the lower surface electrodes 8, 9. Has a plating layer made of a metal having excellent solder bonding properties such as solder.

  The chip resistor 1 having this configuration is soldered by performing soldering to a printed circuit board or the like on the terminal electrodes 6 and 7 formed on the two long side surfaces 2a and 2b of the rectangular insulating substrate 2. The area can be increased, and the thermal stress acting on the soldering portion due to thermal expansion / contraction can be reduced.

  On the other hand, the resistance film 5 is formed so as to extend over the entire length in the longitudinal direction of the rectangle in the insulating substrate 2, so that the length of the current path in the resistance film 5 is set to be rectangular. This can be increased as compared with the case where it is formed so as to extend in a direction perpendicular to the longitudinal direction.

  In this case, as described above, when the resistance film is formed by screen printing as described above, in addition to providing the entering groove 5c at the same time, the trimming groove 5d is engraved, thereby forming a zigzag folded shape. By configuring, the length of the current path can be greatly increased.

  In particular, the length of the current path is such that the narrow width portions 5a and 5b are integrally provided at both ends in addition to the resistance film 5 being folded as described above. Can be made longer by adopting a configuration in which the second upper portions 3b and 4b of the upper surface electrodes 3 and 4 are connected in an overlapping manner.

  Next, FIG. 4 shows a chip resistor 1 'according to the second embodiment.

  This chip resistor 1 'has extended portions 5a', 5a, 5b extending in the same direction as the second portion of each upper surface electrode and overlappingly connected to the narrow portions 5a, 5b at both ends of the resistive film 5. 5b 'is provided integrally, and the other configuration is the same as that of the first embodiment.

  When each of the upper surface electrodes 3 and 4 and the resistance film 5 are separately formed by screen printing, there is a printing misalignment between them.

  In this case, as in the first embodiment, the narrow portions 5a and 5b are integrally provided at both ends of the resistance film 5 which is folded in a zigzag manner, and both the narrow portions 5a and 5b are connected to the upper surfaces. If the electrodes 3 and 4 are configured to overlap and connect to the second portions 3b and 4b, a narrow width at both ends of the resistive film 5 due to a printing shift in the longitudinal direction of the resistive film 5 among the printing shifts. Since the overlapping connection area with respect to the second portions 3a and 4a in both the upper surface electrodes 3 and 4 of the portions 5a and 5b is reduced, the heat dissipation from the resistance film 5 through the upper surface electrodes 3 and 4 is reduced. Become.

  On the other hand, as in the second embodiment, the narrow portions 5a and 5b at both ends of the resistance film 5 extend in the same direction as the second portion of the upper surface electrodes and overlap with the second portions. When the extended portions 5a 'and 5b' are integrally provided, the overlapping connection areas for the second portions 3a and 4a of the upper surface electrodes 3 and 4 of the narrow width portions 5a and 5b at both ends of the resistance film 5 are provided. Can be increased by the extension portions 5a 'and 5b' provided integrally with the narrow width portions 5a and 5b regardless of the printing deviation in the longitudinal direction of the resistance film 5. The heat dissipation through the electrodes 3 and 4 can be ensured.

  In manufacturing the chip resistors 1 and 1 'having the above-described configuration, it is preferable to employ the method described below.

  In this manufacturing method, first, as shown in FIG. 5, a pair of L-shaped upper surface electrodes 3 and 4 are formed on the upper surface of a rectangular chip-shaped insulating substrate 2 by screen printing and baking of a material paste. And a pair of lower surface electrodes 8, 9 extending along the long side surfaces 2a, 2b on the lower surface of the insulating substrate 2 by screen printing and baking of a material paste, as shown in FIG. As shown in FIG. 7, in the upper surface of the insulating substrate 2, between the upper surface electrodes 3 and 4, a resistive film 5 having an entrance groove 5c is formed on a thin film having both ends integrated. A step of forming the width portions 5a and 5b or the extension portions 5a 'and 5b' by screen printing and baking of a material paste so that the second portions 3b and 4b of the upper surface electrodes 3 and 4 are overlapped and connected. It has.

  In each of these three steps, the step of forming the upper surface electrode after the step of forming the lower surface electrodes 8, 9 is performed, and then the step of forming the resistance film 5 is performed. Next, the step of forming the resistance film 5 is performed after the step of forming 8, 9 and then the upper surface electrodes 3 and 4 and the second portions 3b and 4b of the narrow portions 5a and 5b in the resistance film 5 or The extension portions 5 a ′ and 5 b ′ can be appropriately replaced, for example, formed so as to be overlapped with each other.

  In the manufacturing method of the present invention, next, the resistance value of the resistance film 5 is measured on the resistance film 5 by contacting the upper surface electrodes 3 and 4 connected to both ends thereof with an energizing probe as shown in FIG. As shown, the trimming groove 5d is engraved to adjust the resistance value to a predetermined value.

  The cutting of the trimming groove 5d to the resistance film 5 is performed in a portion of the upper surface electrodes 3 and 4 where the first portions 3a and 4a are not present outside the resistance film 5 in a plan view. It can be avoided that the first portions 3a and 4a out of 3 and 4 obstruct the trimming groove 5b.

  In the manufacturing method of the present invention, next, as shown in FIG. 9, a cover coat 10 covering the resistance film 5 is formed on the upper surface of the insulating substrate 2 by screen printing and baking of a material paste, 10, terminal electrodes 6 and 7 are provided on both long side surfaces 2 a and 2 b of the insulating substrate 2, and the first portions 3 a and 4 a of the upper surface electrodes 3 and 4 and the first parts 3 and 4 are formed by applying and baking a material paste. A step of forming a part of both of the lower surface electrodes 8 and 9 so as to be overlapped with each other, a barrel plating treatment on the surfaces of the upper surface electrodes 3, 4, the terminal electrodes 6, 7 and the lower surface electrodes 8, 9, etc. And a step of forming a metal plating layer.

  Through these steps, the chip resistors 1 and 1 'having the above-described configuration can be manufactured at a low cost.

It is a top view which shows the chip resistor by 1st Embodiment. It is the II-II sectional view taken on the line of FIG. FIG. 3 is a sectional view taken along line III-III in FIG. 1. It is a top view which shows the chip resistor by 2nd Embodiment. It is a perspective view which shows a 1st manufacturing process. It is a perspective view which shows a 2nd manufacturing process. It is a perspective view which shows a 3rd manufacturing process. It is a perspective view which shows a 4th manufacturing process. It is a perspective view which shows a 5th manufacturing process. It is a perspective view which shows a 6th manufacturing process.

Explanation of symbols

1, 1 'chip resistor 2 insulating substrate 2a, 2b long side surface 2c, 2d short side surface of insulating substrate 3, 4 upper surface electrode 3a, 4a first portion of upper surface electrode 3b, 4b second of upper surface electrode Part 5 Resistive film 5a, 5b Narrow width part of resistive film 5c Intrusion groove 5d Trimming groove 6, 7 Terminal electrode 8, 9 Bottom electrode 10 Cover coat

Claims (7)

An insulating substrate having a rectangular shape in plan view, a resistance film formed on the upper surface of the insulating substrate so as to extend in the longitudinal direction of the rectangle, a pair of upper surface electrodes formed on the upper surface of the insulating substrate, and the insulating substrate A chip resistor comprising a pair of terminal electrodes formed on each of two parallel side surfaces so as to be electrically connected to the upper surface electrode;
A first portion of each of the upper surface electrodes, the first portion extending along one of the long side surfaces adjacent to one of the two long side surfaces of the rectangle of the insulating substrate; The rectangular shape of the insulating substrate is formed in an L shape in plan view so as to comprise a second portion extending along one short side surface adjacent to one short side surface of the two short side surfaces, The first upper electrode of each of the upper surface electrodes is adjacent to the other long side surface of the two long side surfaces of the rectangle of the insulating substrate and extends along the other long side surface; One of the two short side surfaces in the rectangle of the substrate is formed in an L shape in plan view so as to be composed of a second portion extending along the other short side surface adjacent to the other short side surface. , Both ends of the resistive film are connected to the one upper surface electrode. And the second portion of the other upper surface electrode is electrically connected to the second portion, and one terminal electrode of the terminal electrodes is disposed on one longitudinal side surface of the insulating substrate on the one upper surface. It is formed so as to be electrically connected to the first portion of the electrode, and the other terminal electrode of the terminal electrodes is electrically connected to the other longitudinal side surface of the insulating substrate and to the first portion of the other upper surface electrode. A chip resistor formed to be connected to the chip resistor.   In the description of claim 1, a portion between one end of the resistive film connected to the second portion of the one upper electrode and the other end connected to the second portion of the other upper electrode is: A chip resistor that is formed in a zigzag fold.   3. The narrowed portion according to claim 2, wherein one end connected to the second portion of the one upper surface electrode and the other end connected to the second portion of the other upper surface electrode of the resistance film are each a narrow portion. A chip resistor, characterized in that it is formed.   4. The extension part according to claim 3, wherein the extension part extending in the same direction as the second part of each upper surface electrode is overlapped with the narrow part at one end and the other end of the resistance film. Chip resistor characterized by the above.   In any one of Claims 1-4, the length dimension along the said long side surface in the 1st part of either one or both of each said upper surface electrode is longer than the length dimension in the said long side surface. A chip resistor which is shortened and is provided with a trimming groove for the resistance film in the shortened portion. A step of forming a resistive film on the upper surface of the insulating substrate that is rectangular in plan view so as to extend in the longitudinal direction of the rectangle, a step of forming a pair of upper surface electrodes on the upper surface of the insulating substrate, and a parallel to each other in the insulating substrate Forming a terminal electrode on each of the two side surfaces, and a method of manufacturing a chip resistor comprising:
The step of forming each upper surface electrode includes the step of forming one upper surface electrode of each of the upper surface electrodes adjacent to one long side surface of the two long side surfaces of the rectangle of the insulating substrate. And a second portion extending along one short side surface adjacent to one short side surface of the two short side surfaces in the rectangle of the insulating substrate. The other upper side electrode is formed adjacent to the other long side surface of the two long side surfaces in the rectangle of the insulating substrate. And a second portion extending along the other short side surface adjacent to the other short side surface of the two short side surfaces of the rectangle of the insulating substrate. It is a process of forming an L shape visually.
The step of forming the resistive film is a step of forming both ends of the resistive film so as to be electrically connected to the second portion of each upper surface electrode;
The step of forming each terminal electrode includes electrically connecting one of the terminal electrodes to the first portion of the one upper surface electrode and the first portion of the other upper electrode of the other terminal electrode. A method of manufacturing a chip resistor, characterized by being a step of forming so as to be connected. 7. The method according to claim 6, wherein the step of forming each of the upper surface electrodes includes a length dimension along the long side surface in the first part of either one or both of the upper surface electrodes. This is a process of forming shorter than the length dimension in
A chip resistor comprising a step of forming a trimming groove in a portion of the resistive film that does not have the first portion in plan view before the step of forming the terminal electrodes. Manufacturing method.

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