JP2005045060A - Printed circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the occurrence of cracks and to suppress the progress of graphitizing of a base material even when a crack is generated. <P>SOLUTION: A printed circuit board 10 has a base material 11 on which an electronic component 20 is to be mounted. A conductive pattern 131 is formed on the surface of the base material 11, and connected to a land 136 arranged in a through hole 15 penetrated in the thickness direction of the base material 11. The lead 21 of the electronic component 20 is inserted into the land 136 and connected to the land 136 through solder 16. A through hole 31 penetrated in the thickness direction of the base material similarly to the through hole 15 is formed on the base material 11. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a printed circuit board used for an electric circuit.

  As a method for realizing an electric circuit, a printed circuit board (Printed Circuit Board: PCB) in which a wiring (conductive pattern) is provided with a copper foil on a plate-like base material made of glass epoxy or the like is manufactured. A method of mounting an electrical component at a predetermined position on a printed board is known. A printed circuit board is widely used because a conductive pattern can be realized in a printing process, whereby wiring to an electrical component can be reliably and precisely performed.

  A plurality of through holes into which electrical component leads are inserted are formed in the substrate of the printed circuit board, and lands made of conductive members are formed in the vicinity of the inner peripheral wall and the opening of the through holes. Then, the lead of the electrical component is inserted into the land, the heat-melted solder is poured between the lead and the land, and the electrical component is mounted on the printed circuit board by electrically connecting the land and the lead. The In addition, as a method for mounting an electrical component on a printed circuit board, in addition to the above-described method using a through hole, surface mounting in which a land arranged on a substrate surface and a lead having a flat portion are surface-bonded by soldering is called. There is a way.

  Here, especially when an electrical component that becomes hot when power is supplied at a high voltage is mounted on the printed circuit board, the electrical component will repeatedly generate heat each time the printed circuit board is energized. In some cases, thermal expansion occurs in the printed circuit board and cracks occur in the solder joining the leads and lands of the electrical component. Thus, when a high voltage is applied to the solder from the conductive pattern via the land in a state where a crack is generated in the solder, an arc discharge is generated between the cracks. When arc discharge occurs, the temperature in the vicinity of the crack becomes higher, and the flux contained in the solder, the flux contained in the base material, glass epoxy, and the like are carbonized and graphitized together with the conductive pattern.

  Thus, a new electric circuit having a resistance value is formed by graphitizing the base material. Since a high voltage is applied to the conductive pattern, further arc discharge occurs between the electric circuit and the conductive pattern due to the graphitization, and the graphitization of the base material progresses, and between adjacent lands and lands and between the lands. -A short circuit may occur between conductive patterns. In particular, in a multilayer printed circuit board, conductive patterns are arranged in a complicated manner, and the possibility of a short circuit with a conductor pattern in another layer is increased.

For example, even if an electric circuit formed by graphitization of the base material and a grounding pattern which is a grounded conductive pattern are short-circuited, the electric circuit itself has a resistance value, so that no overcurrent flows in the electric circuit. For this reason, it is difficult to discover the graphitization of the base material with fuses and breakers that are overcurrent protection devices. On the other hand, Patent Document 1 proposes a method of arranging a leakage detection device on a substrate. According to this, if the leakage of the electric circuit can be detected using the leakage detection device, the base material can be found to be graphitized due to a short circuit between the electric circuit and the ground pattern.
JP 2002-199575 A

  However, in the technique described in Patent Document 1, since the leakage in the circuit cannot be detected until the new circuit formed by graphitization and the ground pattern are short-circuited, depending on the arrangement state of the conductive pattern, There is a problem that the graphitization of the material proceeds.

  Therefore, an object of the present invention is to provide a printed circuit board that suppresses the generation of cracks and suppresses the progress of graphitization of the base material even when the cracks are generated.

Means for Solving the Problems and Effects of the Invention

  The printed circuit board of the present invention is a single-layer or multi-layer printed circuit board used for an electric circuit, and is bonded to a base material on which a plurality of electric components are mounted, and leads of the electric components, and power is supplied to the electric components. , A plurality of conductor patterns formed so as to be joined to the lands, and a through hole penetrating in the thickness direction of the base material.

  According to this, even when an electrical component that becomes high temperature by supplying power at a high voltage is mounted on the printed circuit board, a through-hole is formed in the base material. Thermal expansion can be absorbed. Therefore, cracks are less likely to occur at the portion where the lead and land of the electrical component are joined. In addition, even if a crack occurs in the part where the lead and land of the electrical component are joined and arc discharge occurs between the cracks, the through hole prevents the progress of graphitization from the vicinity of the land of the base material. be able to.

  In the present invention, the through hole is preferably formed between the adjacent lands. As a result, when the graphitization of the base material proceeds, the lands are prevented from being connected to each other by the electric path formed by the graphitization by the through-holes, so that a short circuit between the lands can be prevented.

  In the present invention, it is preferable that the through hole is disposed between the land and a conductor pattern formed in the vicinity of the land. Accordingly, when the graphitization of the base material proceeds, the land and the conductor pattern are prevented from being connected by the electric path by the graphitization by the through hole, so that the short circuit between the land and the conductor pattern can be prevented.

  In the present invention, it is preferable that the length of the through hole is larger than the diameter of the land. As a result, the generation of cracks due to thermal expansion of the printed circuit board can be suppressed, and the progression of graphitization can be prevented even when cracks occur.

  At this time, the through hole may be formed long in a direction orthogonal to the direction connecting the adjacent lands. Thereby, it can prevent more effectively by a through-hole that adjacent lands connect with the electric circuit by the graphitization of a base material.

  At this time, the width in the direction connecting the lands adjacent to each other of the through-holes may exist up to the vicinity of the lands. Thereby, since thermal expansion of a printed circuit board can be absorbed more effectively, generation | occurrence | production of a crack can be suppressed.

  At this time, the through hole may be formed long in a direction orthogonal to a direction connecting the land and the conductor pattern formed in the vicinity of the land. Thereby, it can prevent more effectively by a through-hole that a land and a conductor pattern are connected with the electric circuit by graphitization.

  At this time, the width of the through hole in the direction connecting the land and the conductor pattern formed in the vicinity of the land may exist in the vicinity of the land and the conductor pattern. Thereby, since thermal expansion of a printed circuit board can be absorbed more effectively, generation | occurrence | production of a crack can be suppressed.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of an apparatus to which a power supply apparatus including a printed board according to the present invention is applied. Here, the apparatus 90 is, for example, a photographic processing apparatus, but a detailed description regarding the photographic processing will be omitted.

  As shown in FIG. 1, the device 90 includes a power supply device 1, a power source 2, a leakage breaker 3, a control device 4, and a plurality of load devices 5. The power supply device 1 distributes the input high voltage power and supplies the distributed power to each load device 5. The power source 2 is a source of high-voltage power supplied to the power supply device 1. The earth leakage breaker 3 is an earth leakage detection device that relays high-voltage power supplied from the power source 2 to the power supply device 1 and monitors the power supply device 1 for electric leakage. And when the leakage of the power supply device 1 is detected, the power supply to the power supply device 1 is immediately cut off. The control device 4 is connected to the power supply device 1 and controls power supply to each load device 5 by the power supply device 1. The load device 5 is various devices that receive power supply from the power supply device 1, such as a heater, a motor, and other control devices.

  Next, the power supply device 1 will be described with reference to FIG. FIG. 2 shows the contents of silk printing applied to the surface of the printed circuit board 10.

  As shown in FIG. 2, the electric circuit board of the power supply device 1 includes a terminal TA3 constituted by a plurality of terminals T1 to T5, capacitors C1 and C2, surge absorbers ZNR1 to ZNR4, connectors P641, P644, P646, P648, and P660. , P662, magnet relays X1, X3, X4, solid state relays SSR1 to SSR8 and the like.

  The terminal TA3 is for receiving high voltage power from the power source 2 via the leakage breaker 3. Capacitors C1 and C2 remove high-frequency noise from high-voltage power input to terminal TA3. The surge absorbers ZNR1 to ZNR4 are for removing surges generated in the high voltage power input to the terminal TA3. The connector P648 is for connecting to the control device 4. Connectors P641, P644, P646, P660, and P662 are for connection to the load device 5. The magnet relays X1, X3, and X4 and the solid state relays SSR1 to SSR8 start or stop supplying power to the load device 5 under the control of the control device 4. In addition, the input part of solid state relay SSR1-SSR8 is supplied with electric power from the output side contact of magnet relay X1, X3, X4.

  The electric circuit board of the power supply device 1 is realized by mounting the above-described electric components on the printed board 10. 3 is a cross-sectional view of the printed circuit board 10 taken along the line AA in FIG. As shown in FIG. 3, the printed circuit board 10 includes a base material 11, lands 136, conductive patterns 131 and 132, a through hole 15, and a through hole 31. The base material 11 has a configuration in which four plate-like members 11a to 11d made of glass epoxy or the like are laminated in order, the first layer is the plate-like member 11a, the second layer is the plate-like member 11b in order from the top, The third layer is a plate-like member 11c, and the fourth layer is a plate-like member 11d.

  As shown in FIG. 3, the through hole 15 is a hole penetrating in the thickness direction of the substrate 11, and a substantially cylindrical land 136 is disposed so as to cover the inner peripheral surface of the through hole 15 and the upper and lower openings. ing.

  On the upper end and the lower end of the land 136, hook-shaped protrusions 12a and 12b are formed which protrude in the surface direction of the upper surface and the lower surface of the base material 11, and the upper protrusion 12a and the lower protrusion 12b The base material 11 exists between them. As shown in FIG. 4, an appropriate number of through holes similar to the through holes 15 are formed in the printed circuit board 10 where the above-described electrical components are disposed, and landed in each of these through holes. Lands similar to 136 are arranged.

  In FIG. 3, the conductor pattern 131 is formed along the upper surface of the substrate 11 (the upper surface of the first layer 11 a), and is joined to the upper protruding portion 12 a of the land 136. A plurality of conductor patterns are also formed on the first to fourth layers 11a to 11d of the base material 11 as will be described later, and these conductor patterns are also joined to appropriate lands as necessary.

  The electrical component 20 corresponds to the terminal T2 constituting the terminal TA3 shown in FIG. The electrical component 20 is formed with a lead 21 extending vertically from the lower surface thereof. As shown in FIG. 3, the lead 21 of the electrical component 20 is inserted and disposed at substantially the center portion of the through hole 15. Then, the solder 16 containing zinc and tin, which are thermally melted, is poured between the lead 21 and the land 136, so that the electrical component 20 and the land 136 are electrically joined via the solder 16. Yes. Therefore, the electrical component 20 and the conductor pattern 131 are joined via the solder 16 and the land 136. The conductor pattern is a copper foil member for wiring with respect to each electrical component mounted on the printed circuit board 10, and is joined to an appropriate land. The lead 21 is made of a metal and can be energized to the electrical component 20. Also, leads similar to the leads 21 are formed on other electrical components.

  FIGS. 4 to 7 show conductor patterns and a plurality of lands formed on plate-like members 11a to 11d (first to fourth layers 11a to 11d) formed by laminating the base material 11. FIG. As shown in FIG. 4 to FIG. 7, a plurality of conductor patterns are formed on the first to fourth layers, and a plurality of the above-described electrical components are formed on the conductor pattern and the printed circuit board 10 in any layer. The desired electric circuit is configured by connecting via lands existing in the through-hole portion.

  For example, on the first layer 11a of the substrate 11 shown in FIG. 4, a ground pattern 121a, which is a grounded conductive pattern, is joined to lands 71a and 71b that are joined to the leads of the AC input / output units of the solid state relays SSR1 to SSR8. 72a, 72b, 73a, 73b, 74a, 74b, 75a, 75b, 76a, 76b, 77a, 77b, 78a, 78b and lands 81, 82 joined to the leads of the control input of the solid state relays SSR1 to SSR8, 83, 84, 85, 86, 87 and 88 are formed in the vicinity. Further, in the fourth layer 11d of the base material 11 shown in FIG. 7, a ground pattern 121b is formed in a portion overlapping with the ground pattern 121a portion other than the portion in the vicinity of the solid state relays SSR1 to SSR8 in the stacking direction.

  The conductive patterns 115 and 116 formed on the second layer 11b and the fourth layer 11d are joined to the lands 35 and 36 joined to the lead of the terminal TA3, and at the input side of the magnet relays X1, X3, and X4. It is also joined to lands 38 to 40 which are joined to the contact leads. In this way, power is supplied to the magnet relays X1, X3, and X4.

  The conductive patterns 122a and 122b formed in the first to third layers 11a to 11c and the conductive pattern 122c formed in the first layer are joined to the leads of the output side contacts of the magnet relays X1, X3, and X4. In addition to being joined to the lands 41a to 41c, the lands 42a to 42g are also joined to the leads of the input side contacts of the fuses F4 to F10 (see FIG. 2). The conductive patterns 123a to 123g formed in the third layer 11c and the fourth layer 11d are joined to the lands 43a to 43g joined to the leads of the output side contacts of the fuses F4 to F10, and the solid state relays SSR1 to SSR1. It is also joined to lands 71a to 78a which are joined to the leads of the input side contact of SSR8. Thus, a power supply system circuit from the terminal TA3 to the solid state relays SSR1 to SSR8 is configured.

  Further, in order to control the magnet relays X1, X3 and X4, the conductive pattern 125b of the second layer 11b joined to the lands 92 to 94 joined to the leads of the control input portions of the magnet relays X1, X3 and X4 is formed. The conductive pattern group 125a of the fourth layer 11d is formed to be joined to the lands 92 to 94 directly or via the conductive pattern 125b. Further, in order to control the solid state relays SSR1 to SSR8, the conductive pattern group 126 of the fourth layer 11d joined to the lands 81 to 88 joined to the leads of the control input portions of the solid state relays SSR1 to SSR8 is formed. ing. As described above, since a plurality of conductor patterns and lands are formed in each of the layers 11a to 11d, each electrical component is connected via the lands and the conductor patterns.

  8-11 has shown the enlarged view for every layer of the base material 11 of the area | region enclosed with the dashed-two dotted line in FIG. As shown in FIGS. 8 to 11, a plurality of through holes 31 to 34 are formed in the base material 11 of the printed circuit board 10. As shown in FIG. 8, the first layer 11a has conductor patterns 131 joined to the lands 36 and 136 joined to the leads of the terminals T1 and T2, and lands 137 to 140 joined to the leads of the capacitors C1 and C2. A conductor pattern 132 that is arranged in the vicinity and is joined to the lands 141 to 144 that are joined to the leads of the input side contacts of the surge absorbers ZNR1 to ZNR4, and the land 151 that is joined to the leads of the output side contacts of the surge absorber ZNR1. And a conductor pattern 133 to be joined.

  In FIG. 8, the through hole 31 is disposed between the conductor pattern 131 and the conductor pattern 132. The through hole 31 is formed in an elongated shape, and its longitudinal direction is parallel to a direction orthogonal to the direction connecting adjacent lands 36. The length in the longitudinal direction of the through hole 31 has a length corresponding to the upper side of the conductor pattern 131. The through holes 32 are arranged between the conductor patterns 131. The through hole 32 is formed long in the direction connecting adjacent lands 36. The length of the through hole 32 in the longitudinal direction has a length corresponding to the left and right sides of the conductor pattern 131.

  In FIG. 8, the through hole 33 is disposed between adjacent lands 141 and 151. The through-hole 33 is formed long in a direction orthogonal to the direction connecting the lands 141 and 151, and the width in the direction connecting the lands 141 and 151 is present in the vicinity of the lands 141 and 151. Further, the through hole 34 is disposed between the land 152 and the land 142 joined to the lead of the output side contact of the surge absorber ZNR2. The through-hole 34 is formed long in a direction orthogonal to the direction connecting the lands 142 and 152, and the width in the direction connecting the lands 142 and 152 exists to the vicinity of the lands 142 and 152.

  In addition, since the through-holes 31-34 mentioned above are penetrated in the thickness direction of the base material 11 as shown in FIGS. 9-11, the position of the 2nd-4th layer 11b-11d which overlaps with the 1st layer 11a. Also formed.

  Further, as shown in FIG. 9, the second layer 11b has a conductor pattern 161 joined to a land 136 joined to the lead of the terminal T2 and lands 138 and 139 joined to the leads of the capacitors C1 and C2, and a terminal. A conductor pattern 162 is formed to be joined to the land 36 joined to the lead of T1 and the land 137 joined to the lead of the capacitor C1. The conductor patterns 161 and 162 are separated from each other.

  Further, as shown in FIG. 10, the third layer 11c is joined to lands 136 joined to the leads of the terminal T2 and lands 138 and 139 joined to the leads of the capacitors C1 and C2, and the lands 137, 141 and 151 are joined. A conductor pattern 163 disposed in the vicinity is formed.

  Further, as shown in FIG. 11, the fourth layer 11d has a land 142 which is joined to the conductor pattern 164 similar to the conductor pattern 131 of the first layer 11a and the leads of the input side contacts of the surge absorbers ZNR2 to ZNR4. Conductor pattern 165 joined to ˜145, conductor pattern 166 joined to land 152 joined to the lead of the output side contact of surge absorber ZNR2, and conductor pattern 116 described above are formed.

  Since the length in the longitudinal direction of each of the through holes 31 to 34 passing through the first to fourth layers 11a to 11d is larger than the diameter of any land, the terminal TA3, the capacitors C1 and C2, and the surge absorber ZNR1 When energizing an electrical component such as ~ ZNR4, the thermal expansion of the printed circuit board 10 in the vicinity of the electrical component due to the heat generated by each electrical component is suppressed, so that cracks are not generated in the solder that joins between the land and the lead of the electrical component. be able to. Further, since the width in the short direction is close to the lands 141, 142, 151, 152 and the conductor patterns 132, 133 like the through holes 33, 34, the width of the through holes 33, 34 is increased, and the printed board The thermal expansion of 10 can be absorbed more effectively. Therefore, it is possible to suppress the occurrence of solder cracks as described above. That is, the thermal expansion generated in the printed circuit board 10 due to the heat generation of the electrical component narrows the space between the through hole and the lead of the electrical component and applies compressive stress to the solder. Since it can be released (absorbed), cracks are less likely to occur in the solder.

  Subsequently, when the energized electrical component 20 generates heat, thermal expansion occurs in the printed circuit board 10 in the vicinity of the electrical component 20, and a crack 18 is generated in the solder 16 that joins the lead 21 and the land 136 of the electrical component 20. Is described below. FIG. 12 is a cross-sectional view taken along the line BB in FIG. 8, (a) is a cross-sectional view of the main part of the printed circuit board showing a situation where cracks are generated in the solder, and (b) is an arc on the cracks generated in the solder. It is principal part sectional drawing of a printed circuit board which shows the condition where discharge generate | occur | produced and the new electric circuit was formed.

  As shown in FIG. 12A, since the printed board 10 has a through-hole 31, even if the printed circuit board 10 is thermally expanded by energization of the electrical component 20, the printed circuit board 10 is heated. Since the thermal expansion of 10 is absorbed by the through-hole 31, cracks are less likely to occur in the solder 16, but excessive heat generation or repetition by the electrical component 20 that becomes high temperature by supplying high-voltage power in particular. In some rare cases, cracks 18 may occur in the solder 16 due to thermal expansion of the printed circuit board 10. If a high voltage is applied to the solder 16 from the conductive pattern 131 via the land 136 while the crack 18 is formed on the solder 16, an arc discharge occurs between the cracks 18 as shown in FIG. . When the arc discharge occurs, the vicinity of the crack 18 becomes high temperature, and the flux contained in the solder 16, the flux contained in the substrate 11, the glass epoxy, etc. are carbonized and graphitized together with the conductive pattern. When the base material 11 is graphitized, a new electric circuit 19 having a resistance value is formed. The electric circuit 19 further grows in the right direction in the figure by arc discharge.

  However, the growth of the electric circuit 19 that grows rightward in FIG. 12B due to arc discharge between the cracks 18 is suppressed by the through hole 31. In other words, the portion that becomes carbonized due to arc discharge between the cracks 18 is interrupted at the through hole 31, and the electric circuit 19 cannot grow. Moreover, since the through-hole 31 is penetrated in the thickness direction of the base material 11, the high-temperature portion is cooled by the air passing through the through-hole 31, so that the progress of graphitization of the electric path 19 is suppressed. It also becomes. Therefore, it is possible to prevent the base material 11 from graphitizing and the electric circuit 19 from being connected to the conductor pattern 132 on the first layer 11a.

  As described above, the printed circuit board 10 according to the present embodiment has a plurality of through-holes in the base material 11 even when electrical components that are heated to a high voltage when power is supplied are mounted on the printed circuit board 10. Since 31-34 are formed, the thermal expansion of the printed circuit board 10 by the heat_generation | fever of an electrical component can be absorbed. Therefore, cracks are less likely to occur in the solder joining the leads and lands of the electrical component. Further, even when a crack is generated in the solder joining the lead and the land of the electrical component and an arc discharge is generated between the cracks, the graphitization proceeds from the vicinity of the land of the base material 11 through the through holes 31 to 31. 34 can be suppressed.

  Further, since the through hole 31 of the printed circuit board 10 is formed between the conductive patterns 131 and 132, a crack is generated in the solder near the land 36 and the land 136, and an electric circuit formed by graphitization of the base material 11 is formed. Even if it grows to the conductive pattern 132 side, the growth of the electric circuit is suppressed by the through hole 31. Therefore, it can prevent more effectively that the conductive pattern 131 and the conductive pattern 132 are connected by the electric circuit by the graphitization of the base material 11. FIG. Therefore, it is possible to prevent the short circuit between the lands 136 and the lands 141 to 144 and between the lands 136 and the conductive patterns 132 connected by the electric circuit.

  Further, since the through holes 32 of the printed circuit board 10 are formed between the conductive patterns 131, cracks are generated in the lands 36 and the solder near the lands 136, and the electric path formed by graphitization of the base material 11 becomes the conductive pattern. Even if it grows so that 131 may be connected, the growth of the electric circuit can be suppressed by the through-hole 32. Therefore, it is possible to more effectively prevent the conductive patterns 131 from being connected by an electric circuit. Therefore, it is possible to prevent the land 36 and the land 136 from being short-circuited by an electric circuit.

  Further, since the through hole 33 of the printed circuit board 10 is formed between the lands 141 and 151 and between the conductor patterns 132 and 133, a crack is generated in the solder near the lands 141 and 151, Even if the electric circuit formed by graphitization grows so as to connect the lands 141 and 151, the growth can be suppressed by the through-hole 33. Therefore, it is possible to more effectively prevent the conductive patterns 132 and 133 from being connected by the electric circuit. Therefore, it is possible to prevent a short circuit between the land 141 and the land 151, between the land 141 and the conductive pattern 133, and between the land 151 and the conductive pattern 132 by the electric circuit.

  Further, since the through hole 34 of the printed circuit board 10 is formed between the lands 142 and 152 and between the land 152 and the conductive pattern 142, a crack is generated in the solder near the lands 142 and 152, and the base material 11. Even if the electric circuit formed by the graphitization of the lands grows so as to connect the lands 142 and 152, the growth can be suppressed by the through holes 34. Therefore, it is possible to more effectively prevent the land 152 and the conductive pattern 132 from being connected by the electric circuit. Therefore, it is possible to prevent the short circuit between the land 142 and the land 152 and the conductive pattern 165 to the conductive pattern 166 connected by the electric circuit.

  In addition, since the through-holes 31-34 are formed long, the progress of the electric circuit by graphitization can be suppressed in a wide range.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various design changes can be made as long as they are described in the claims. For example, it is sufficient that at least one or more through holes are provided in the printed circuit board 10 in the present embodiment, and the thermal expansion of the printed circuit board due to the heat generated by the electrical components is absorbed in the through holes as described above, Even if a crack occurs and the base material is graphitized, it may be suppressed by the through hole. In addition, the through holes 31 to 34 of the present embodiment have an elongated shape (ellipse shape), but may have any shape and effectively absorb the thermal expansion of the printed circuit board 10 or What is necessary is just to suppress the progress of graphitization. The printed circuit board may have a single layer structure.

  The printed circuit board according to the present invention can also be applied to an apparatus to which a printed circuit board other than the power supply apparatus of the present embodiment is applied.

It is a block diagram which shows the structure of the apparatus with which the electric power supply apparatus containing the printed circuit board by this invention was applied. It is explanatory drawing which shows the content of the silk printing of the printed circuit board used for the electric power supply apparatus shown in FIG. It is AA sectional drawing of the printed circuit board in FIG. It is a top view of the 1st layer of the printed circuit board used for the electric power supply apparatus shown in FIG. It is a top view of the 2nd layer of the printed circuit board used for the electric power supply apparatus shown in FIG. It is a top view of the 3rd layer of the printed circuit board used for the electric power supply apparatus shown in FIG. It is a top view of the 4th layer of the printed circuit board used for the electric power supply apparatus shown in FIG. FIG. 5 is an enlarged plan view of a first layer of a printed board showing a region surrounded by a two-dot chain line in FIG. 4. FIG. 5 is an enlarged plan view of a second layer of the printed board showing a region surrounded by a two-dot chain line in FIG. 4. FIG. 5 is an enlarged plan view of a third layer of the printed board showing a region surrounded by a two-dot chain line in FIG. 4. FIG. 5 is an enlarged plan view of a fourth layer of the printed board showing a region surrounded by a two-dot chain line in FIG. 4. FIG. 9 is a cross-sectional view taken along the line B-B in FIG. 8, where (a) is a cross-sectional view of the main part of the printed circuit board showing a situation in which cracks have occurred in the solder; It is principal part sectional drawing of the printed circuit board which shows the condition in which the new electric circuit was formed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power supply apparatus 2 Power supply 3 Earth leakage breaker 4 Control apparatus 5 Load apparatus 10 Printed circuit board 11 Base material 15 Through hole 16 Solder 20 Electrical component 21 Lead 31, 32, 33, 34 Through-hole 131 Conductor pattern 136 Land

Claims (8)

A single-layer or multi-layer printed circuit board used for electric circuits,
A substrate on which a plurality of electrical components are mounted;
A plurality of lands bonded to the leads of the electrical component and supplying power to the electrical component;
A plurality of conductor patterns formed to be joined to the land;
A printed circuit board comprising a through hole penetrating in the thickness direction of the base material.   The printed circuit board according to claim 1, wherein the through hole is formed between the adjacent lands.   The printed circuit board according to claim 1, wherein the through hole is disposed between the land and a conductor pattern formed in the vicinity of the land.   The printed circuit board according to claim 1, wherein a length of the through hole is larger than a diameter of the land.   The printed circuit board according to claim 4, wherein the through hole is formed long in a direction orthogonal to a direction connecting the adjacent lands.   The printed circuit board according to claim 5, wherein a width in a direction connecting the lands adjacent to each other of the through-holes exists up to the vicinity of the lands.   The printed circuit board according to claim 4, wherein the through hole is formed long in a direction orthogonal to a direction connecting the land and a conductor pattern formed in the vicinity of the land. The printed circuit board according to claim 7, wherein a width of the through hole in a direction connecting the land and a conductor pattern formed in the vicinity of the land exists to the vicinity of the land and the conductor pattern. .

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