Printed wiring board
Patent Information
- Application Number
- PCT/JP2024/017743
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-09-19
- Filing Date
- 2024-05-14
- Publication Date
- 2025-03-27
Smart Images
Figure JP2024017743_27032025_PF_FP_ABST
Abstract
Description
printed wiring board
[0001] The present invention relates to a printed wiring board.
[0002] Electronic components mounted on printed wiring boards are mainly divided into insertion type components and surface mount type components. Insertion type components have wire-shaped electrode terminals called leads, and when mounting insertion type components on a printed wiring board, the leads are inserted into through holes in the printed wiring board by machine or by hand and soldered.
[0003] Leads come in a variety of cross-sectional shapes, including circular, angular, flat, etc. When a lead with a flat cross-section is inserted into a circular through-hole, the lead and through-hole shapes may not match, causing the lead to deform and the component to tilt on the printed wiring board.
[0004] One way to prevent component tilt is to make the through-holes in the printed wiring board oval to match the flat shape of the leads, but electronic components have become increasingly miniaturized in recent years, making it difficult to drill oval holes of the optimal size for small, flat leads. If the holes are enlarged to a size that can be drilled with a drill, the through-holes will become larger than the leads, resulting in a problem of greater component misalignment.
[0005] Furthermore, as hole processing devices other than drilling devices, router devices and laser devices are conceivable, but router devices take a long time to process and laser devices are expensive, so both increase costs.
[0006] As a technology for suppressing tilt and misalignment of a printed wiring board, Patent Document 1 discloses a printed wiring board provided with through holes into which external terminals 10 for positioning are inserted, and with slits formed around the through holes. By arranging slits around the through holes in the printed wiring board of Patent Document 1, even if slight tilt or deformation of the external terminals occurs, the slits deform only the substrate near the through holes, thereby suppressing tilt and misalignment of the entire printed wiring board.
[0007] Japanese Patent Application Laid-Open No. 2016-6806
[0008] However, in order to prevent tilting and misalignment of components using the technology of Patent Document 1, it is necessary to provide through-holes for positioning in the printed wiring board, which increases processing time and costs. Furthermore, the technology of Patent Document 1 does not facilitate the insertion of leads into through-holes or prevent lead deformation.
[0009] Therefore, an object of the present invention is to provide a technique that can facilitate the insertion of leads into through holes and can prevent misalignment of components.
[0010] In order to solve the above problem, one representative printed wiring board of the present invention is a printed wiring board on which a component having at least two leads is mounted, and is provided with at least two holes for inserting the leads, the holes having at least one first hole whose length in one direction is the length of the lead in that direction plus a predetermined clearance value, and at least one second hole whose length in a direction perpendicular to the one direction is the length of the lead in the direction perpendicular to the one direction plus a predetermined clearance value.
[0011] According to the present invention, it is possible to facilitate the insertion of leads into through holes and to prevent misalignment of components.
[0012] Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments.
[0013] FIG. 1 is a cross-sectional view and a top view illustrating a method for processing a circular through hole in a printed wiring board. FIG. 2 is a cross-sectional view and a top view illustrating a method for processing a circular through hole in a printed wiring board. FIG. 3 is a cross-sectional view and a top view illustrating a method for processing an oval through hole in a printed wiring board. FIG. 4 is a cross-sectional view and a top view illustrating a method for processing an oval through hole in a printed wiring board. FIG. 5 is a cross-sectional view illustrating a method for mounting an insertion-type component on a printed wiring board. FIG. 6 is a cross-sectional view illustrating a method for mounting an insertion-type component on a printed wiring board. FIG. 7 is a cross-sectional view and a top view illustrating a method for mounting an insertion-type component on a printed wiring board. FIG. 8 is a cross-sectional view and a top view illustrating an example of inserting a flat lead into a circular through hole of a size recommended by a manufacturer. FIG. 9 is a cross-sectional view and a top view illustrating an example of inserting a flat lead into a circular through hole of a size recommended by a manufacturer. FIG. 10 is a top view illustrating the size of an oval through hole. FIG. 11 is a view illustrating an example of mounting an insertion-type component on a printed wiring board having an oval through hole. FIG. 12 is a top view illustrating the size of a circular through hole. FIG. 13 is a view illustrating an example of mounting an insertion-type component on a printed wiring board having a circular through hole. FIG. 14 is a cross-sectional view and a top view illustrating an example of mounting an insertion-type component on a printed wiring board having a circular through hole. FIG. 1 is a cross-sectional view and a top view showing an example of a printed wiring board of Example 2. FIG. 2 is a cross-sectional view and a top view showing an example of a printed wiring board of Example 3. FIG. 3 is a cross-sectional view and a top view showing an example of a printed wiring board of Example 4. FIG. 4 is a cross-sectional view and a top view showing an example of inserting a lead having a protrusion shape into a circular through-hole of a size recommended by a manufacturer. FIG. 5 is a cross-sectional view and a top view showing an example of a printed wiring board of Example 5. FIG. 6 is a cross-sectional view and a top view showing an example of a printed wiring board of Example 6. FIG. 7 is a cross-sectional view and a top view showing an example of a printed wiring board of Example 7.
[0014] Hereinafter, an embodiment will be described with reference to the drawings.
[0015] The embodiment described below shows one mode for carrying out the present invention, and the present invention is not limited to this embodiment. In the following drawings, the same devices (members or parts) are designated by the same reference numerals, and, in principle, descriptions of devices that have already been described will be omitted. In the following embodiments, when the number of elements is mentioned, the number is not limited to a specific number, except when the necessity of the number of elements is explained.
[0016] First, a method for processing through holes in a printed wiring board and a method for mounting insertion-type components on a printed wiring board will be explained.
[0017] A printed wiring board is a board in which a copper foil pattern (conductor pattern) is formed on the outer surface (surface of the printed wiring board) or inner surface (inside the printed wiring board) of a substrate (insulated board), and is generally composed of through holes for mounting electronic components on the printed wiring board and signal copper foil patterns for connecting components.
[0018] A through hole is a hole that is drilled into a printed wiring board using a drilling device and copper plated on the inner wall (base material) of the through hole, allowing electrical continuity between the outer and inner surfaces. It serves both as an electrical connection and as a fixing hole for components mounted on the printed wiring board.
[0019] Through holes are generally circular or oval in shape. Copper foil patterns called lands are formed around the through holes on the outer or inner surface of the printed wiring board. Lands are always formed on the outer surface of the printed wiring board for soldering.
[0020] 1A and 1B are a cross-sectional view and a top view illustrating a method for processing a circular through-hole in a printed wiring board.
[0021] As shown in FIG. 1A, printed wiring board 100 includes insulating substrate 204 called a core material, adhesive and insulating substrates 203 and 205 called prepregs, and copper foils 103, 104, 105, and .
[0022] Copper foils 103 and 104 are attached to both sides of substrate 204 in advance. Furthermore, when substrates 203 and 205 sandwich substrate 204 from above and below, and copper foils 105 and 106 are placed on top of them and heated and pressurized, substrates 203 and 205 melt and become closely attached to copper foils 103, 104, 105, and 106. This produces a four-layer printed wiring board with two copper foil pattern layers laminated on the inner layer surfaces.
[0023] The processing of the circular through-hole 102 in the printed wiring board 100 will be described.
[0024] First, as shown in FIG. 1A, a circular hole having an inner wall 101 is formed in a printed wiring board 100 by drilling using a drilling device 301 .
[0025] Next, as shown in FIG. 1B, copper foil 107 is adhered to the inner wall 101 of the hole by copper plating, and a circular through-hole 102 is completed.
[0026] 2A and 2B are a cross-sectional view and a top view illustrating a method for processing an oval through-hole in a printed wiring board.
[0027] The processing of the oval through-holes in the printed wiring board 100 will be described.
[0028] First, as shown in FIG. 2A, holes are drilled in a zigzag pattern in printed wiring board 100 using drilling device 301, thereby forming oval holes having inner walls 101.
[0029] In staggered drilling, after drilling circular hole 501a in printed wiring board 100 with drilling device 301, drilling device 301 is moved horizontally in the direction of arrow 601 to drill hole 501b. Then, drilling device 301 is moved horizontally in the direction of arrow 602 to drill hole 501c, then drilling device 301 is moved horizontally in the direction of arrow 603 to drill hole 501d, and finally drilling device 301 is moved horizontally in the direction of arrow 604 to drill hole 501e. By overlapping circular holes 501a-e in this way, an oval hole is formed. Here, the distance traveled by arrows 601 and 602 must be at least the diameter of drilling device 301.
[0030] Next, as shown in FIG. 2B, copper foil 107 is adhered to inner wall 101 of the hole by copper plating, and an oval through-hole 401 is completed.
[0031] Next, a method for mounting an insertion-type component on the printed wiring board 100 will be described.
[0032] 3A to 3C are cross-sectional views illustrating a method for mounting an insertion-type component on a printed wiring board.
[0033] The insertion type component 701 has leads 702 which are electrode terminals for electrically connecting the insertion type component 701 to the printed wiring board 100 .
[0034] First, as shown in FIG. 3A, the worker recognizes the circular through-hole 102 on the printed wiring board 100, and manually inserts the lead 702 into the circular through-hole 102 in the direction of the arrow 901 while paying attention to the direction and the inclination of the component.
[0035] The lead 702 is inserted into the circular through hole 102 from the A-side 201 side of the printed wiring board 100 so that the tip protrudes to the B-side 202 side.
[0036] Next, as shown in FIG. 3B, an insertion type component 701 is soldered to the printed wiring board 100 by a flow method.
[0037] The flow method is a method in which printed wiring board 100, into which leads 702 of insertion-type component 701 are inserted, is sent by a conveyor to solder bath 801 and soldered.
[0038] The solder bath 801 is a device that jets out liquid molten solder 802 in the direction of the arrow 803. The solder 802 jetted out from the solder bath 801 comes into contact with the B side 202 of the printed wiring board.
[0039] 3C, the molten solder 802 flows from the B-side 202 side through the circular through-hole 102 to the A-side 201 side, and the space between the circular through-hole 102 and the lead 702 is completely filled with the solder 802. As the molten solder 802 hardens, the printed wiring board 100 and the insertion-type component 701 are bonded together.
[0040] 4A and 4B are a cross-sectional view and a top view showing an example of inserting a flat lead into a circular through-hole of a size recommended by the manufacturer.
[0041] The insertion type component 701 includes two leads 702. The leads 702 have a flat cross section, and are arranged in the insertion type component 701 so that the longitudinal directions of the cross sections of the leads 702 are in the same direction.
[0042] The printed wiring board 100 has two circular through holes 102 at positions where two leads 702 of an insertion-type component 701 are inserted, respectively. The diameter size of the circular through holes 102 is the value recommended by the component manufacturer.
[0043] An operator manually inserts two leads 702 of insertion-type component 701 into circular through-hole 102 of printed wiring board 100 in the direction of arrow 901 .
[0044] At this time, as shown in FIG. 4B, the leads 702 may bend within the circular through-holes 102, causing the insertion-type component 701 to tilt relative to the printed wiring board 100.
[0045] This is thought to be because the shape of the circular through hole 102 and the shape of the lead 702 do not match, making insertion difficult.
[0046] Furthermore, in order to prevent misalignment when insert-type component 701 is mounted on printed wiring board 100, diameter 902 of circular through-hole 102 recommended by the component manufacturer is set to be equal to longitudinal length 903 of lead 702, which makes it easy for lead 702 to interfere with circular through-hole 102. Therefore, it is necessary to press lead 702 into circular through-hole 102 with a large force, which makes lead 702 prone to bending when pressed.
[0047] An example in which circular through-holes 102 of the size recommended by the manufacturer are changed to oval through-holes 402 that match the cross-sectional shape of leads 702 in order to prevent tilting of insertion-type component 701 will be described with reference to FIGS. 5A and 5B.
[0048] FIG. 5A is a top view illustrating the size of the oval through-holes.
[0049] The printed wiring board 100 has two oval through holes 402 at positions where two leads 702 of an insertion-type component 701 are inserted, respectively.
[0050] The widthwise length B' of the oval through-hole 402 is set to the widthwise length B of the lead 702 + the clearance value × 2. The clearance value is set to a value that allows the lead 702 to be easily inserted into the oval through-hole 402 and can prevent misalignment of the lead 702 in the widthwise direction.
[0051] Like the widthwise length B', the longitudinal length A' of oval through hole 402 is ideally equal to the longitudinal length A of lead 702 plus the clearance value × 2. However, as described above with reference to Figure 2A, in order to drill oval through hole 402 in printed wiring board 100, the staggered movement distance of drilling device 301 must be at least the diameter of drilling device 301. Therefore, as a constraint on drilling device 301, the longitudinal length A' of oval through hole 402 is twice the widthwise length B' of oval through hole 402, which is greater than the ideal value.
[0052] FIG. 5B is a diagram showing an example in which an insertion-type component is mounted on a printed wiring board having an oval through-hole.
[0053] As shown in Figure 5B, when lead 702 of insertion-type component 701 is inserted into oval through-hole 402, the short-side length B' of oval through-hole 402 is the short-side length B of lead 702 + clearance value x 2, so the short-side deviation of lead 702 indicated by arrow 911 is suppressed.
[0054] However, the gap 410 between the longitudinal direction of the oval through hole 402 and the longitudinal direction of the lead 702 is too large as a clearance value, and therefore, misalignment in the longitudinal direction of the lead 702 as indicated by arrow 910 is likely to occur.
[0055] An example in which the circular through-hole is changed to a size larger than the circular through-hole 102 recommended by the manufacturer in order to prevent tilting of the insertion-type component 701 will be described with reference to FIGS. 5C and 5D.
[0056] FIG. 5C is a top view illustrating the size of the circular through-holes.
[0057] The printed wiring board 100 has two circular through holes 403 at positions where two leads 702 of the insertion-type component 701 are inserted, respectively.
[0058] The diameter A' of the circular through hole 403 is set to the longitudinal length A of the lead 702 plus the clearance value x 2.
[0059] FIG. 5D is a diagram showing an example of mounting an insertion-type component on a printed wiring board having a circular through-hole.
[0060] As shown in Figure 5D, when lead 702 of insertion-type component 701 is inserted into circular through-hole 403, diameter A' of circular through-hole 403 is the longitudinal length A of lead 702 + clearance value x 2, so the longitudinal deviation of lead 702 indicated by arrow 910 is suppressed.
[0061] However, the gap 412 between the circular through hole 403 and the lead 702 in the short-side direction is too large as a clearance value, and therefore misalignment of the lead 702 in the short-side direction, as indicated by the arrow 911, is likely to occur.
[0062] The printed wiring board of the first embodiment will be described with reference to FIG.
[0063] The first embodiment is a printed wiring board in which an oval through hole 402 and a circular through hole 403 are combined.
[0064] FIG. 6 is a cross-sectional view and a top view showing an example of the printed wiring board according to the first embodiment.
[0065] The insertion type component 701 includes two leads 702. The leads 702 have a flat cross section, and are arranged in the insertion type component 701 so that the longitudinal directions of the cross sections of the leads 702 are in the same direction.
[0066] The printed wiring board 100 has an oval through-hole 402 and a circular through-hole 102 at positions where two leads 702 of an insertion-type component 701 are inserted, respectively.
[0067] By combining the oval through hole 402 and the circular through hole 403, the oval through hole 402 suppresses the misalignment of the lead 702 in the short direction indicated by the arrow 911, and the circular through hole 403 suppresses the misalignment of the lead 702 in the long direction indicated by the arrow 910, thereby suppressing the positional misalignment of the insertion type component 701.
[0068] Moreover, the oval through-hole 402 and the circular through-hole 403 are formed to a size that allows clearance for the lengths of the leads 702 in the short and long directions, respectively, so that the leads can be easily inserted into the through-holes.
[0069] In this embodiment, a flat cross-sectional shape of the lead 702 is taken as an example, but this embodiment can be applied to any lead shape such as a wave shape or an oval shape.
[0070] Furthermore, in this embodiment, a combination of an oval through hole and a circular through hole is given as an example, but any shape of through hole may be combined as long as the shape of the through hole is expected to prevent misalignment according to the lead shape.
[0071] Furthermore, in this embodiment, the shape of one through hole is the same in all layers of the printed wiring board 100, but the shape may be different between the outer layer and the inner layer.
[0072] In this embodiment, the lands on the outer surface of the printed wiring board 100 are represented as circles, but the lands may have any shape.
[0073] Although a four-layer printed wiring board is used as an example in this embodiment, the present invention may be applied to a multi-layer printed wiring board or a single-sided printed wiring board. The same effect can also be obtained with printed wiring boards made of any base material.
[0074] According to the first embodiment, it is possible to facilitate the insertion of leads into through holes and to prevent misalignment of components.
[0075] Furthermore, since the through holes can be formed using a drilling device, an increase in costs can be prevented.
[0076] The printed wiring board of the second embodiment will be described with reference to FIG.
[0077] The second embodiment is an example in which an insertion-type component 701 having four leads 702 arranged in a row is mounted on a printed wiring board 100. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.
[0078] FIG. 7 is a cross-sectional view and a top view showing an example of a printed wiring board according to a second embodiment.
[0079] The insertion type component 701 has four leads 702 arranged in a row. The leads 702 have a flat cross section and are arranged in the insertion type component 701 so that the longitudinal direction of the cross section of each lead 702 is in the same direction.
[0080] Printed wiring board 100 has oval through holes 402 at positions where leads 702 on both ends of insertion-type component 701 are inserted, and has circular through holes 403 at positions where the other leads 702 are inserted.
[0081] By combining the oval through hole 402 and the circular through hole 403, the oval through hole 402 suppresses the misalignment of the lead 702 in the short direction indicated by the arrow 911, and the circular through hole 403 suppresses the misalignment of the lead 702 in the long direction indicated by the arrow 910, thereby suppressing the positional misalignment of the insertion type component 701.
[0082] Moreover, the oval through-hole 402 and the circular through-hole 403 are formed to a size that allows clearance for the lengths of the leads 702 in the short and long directions, respectively, so that the leads can be easily inserted into the through-holes.
[0083] In this embodiment, both ends are made of oval through holes 402 and the others are made of circular through holes 403, but the order in which the oval and circular through holes are arranged is not limited to this, and any combination of oval and circular through holes will do.
[0084] In addition, while this embodiment uses an insertion-type component 701 having four leads 702 arranged in a row as an example, the number and arrangement of the leads are not limited to this, and the insertion-type component may have multiple rows of leads. Also, in this embodiment, a flat cross-sectional shape of the leads 702 is used as an example, but this embodiment can be applied to any lead shape, such as a wave shape or an oval shape.
[0085] Furthermore, in this embodiment, a combination of an oval through hole and a circular through hole is given as an example, but any shape of through hole may be combined as long as the shape of the through hole is expected to prevent misalignment according to the lead shape.
[0086] Furthermore, in this embodiment, the shape of one through hole is the same in all layers of the printed wiring board 100, but the shape may be different between the outer layer and the inner layer.
[0087] In this embodiment, the lands on the outer surface of the printed wiring board 100 are represented as circles, but the lands may have any shape.
[0088] Although a four-layer printed wiring board is used as an example in this embodiment, the present invention may be applied to a multi-layer printed wiring board or a single-sided printed wiring board. The same effect can also be obtained with printed wiring boards made of any base material.
[0089] According to the second embodiment, it is possible to facilitate the insertion of leads into through holes and to prevent misalignment of components.
[0090] Furthermore, since the through holes can be formed using a drilling device, an increase in costs can be prevented.
[0091] A printed wiring board according to a third embodiment will be described with reference to FIG.
[0092] The third embodiment is an example in which a plurality of insertion-type components 701 are mounted on a plurality of printed wiring boards 100. In the third embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.
[0093] FIG. 8 is a cross-sectional view and a top view showing an example of a printed wiring board according to a third embodiment.
[0094] The two insertion type components 701a, 701b each have two leads 702, one on top and one on bottom. The leads 702 have a flat cross section and are arranged in the insertion type components 701a, 701b so that the longitudinal directions of the cross sections of the respective leads 702 are in the same direction. The two insertion type components 701a, 701b are mounted side by side on the two printed wiring boards 100a, 100b so that the two leads 702, one on top and one on bottom, are aligned in a row.
[0095] The two printed wiring boards 100a, 100b are provided with oval through holes 402 at positions where leads 702 that are at both ends when insert-type components 701a, 701b are arranged are inserted, and with circular through holes 403 at positions where the other leads 702 are inserted.
[0096] Each of the insertion type components 701a and 701b is connected to the printed wiring board 100a by two leads 702 provided on the upper side, and is connected to the printed wiring board 100b by two leads 702 provided on the lower side.
[0097] By combining the oval through hole 402 and the circular through hole 403, the oval through hole 402 suppresses the misalignment of the lead 702 in the short direction indicated by the arrow 911, and the circular through hole 403 suppresses the misalignment of the lead 702 in the long direction indicated by the arrow 910, thereby suppressing the positional misalignment of the insertion type components 701a and 701b.
[0098] Moreover, the oval through-hole 402 and the circular through-hole 403 are formed to a size that allows clearance for the lengths of the leads 702 in the short and long directions, respectively, so that the leads can be easily inserted into the through-holes.
[0099] In this embodiment, both ends are made of oval through holes 402 and the others are made of circular through holes 403, but the order in which the oval and circular through holes are arranged is not limited to this, and any combination of oval and circular through holes will do.
[0100] In addition, in this embodiment, insertion type components 701a and 701b having two leads 702 arranged above and below each other are given as examples, but the number and arrangement of the leads are not limited to this, and the insertion type components may have multiple rows of leads.
[0101] Furthermore, in this embodiment, a flat cross-sectional shape of the lead 702 is taken as an example, but this embodiment can be applied to any lead shape such as a wave shape or an oval shape.
[0102] Furthermore, in this embodiment, a combination of an oval through hole and a circular through hole is given as an example, but any shape of through hole may be combined as long as the shape of the through hole is expected to prevent misalignment according to the lead shape.
[0103] Furthermore, in this embodiment, the shape of one through hole is the same in all layers of the printed wiring board 100, but the shape may be different between the outer layer and the inner layer.
[0104] In this embodiment, the lands on the outer surface of the printed wiring boards 100a and 100b are represented as circles, but the lands may have any shape.
[0105] Although a four-layer printed wiring board is used as an example in this embodiment, the present invention may be applied to a multi-layer printed wiring board or a single-sided printed wiring board. The same effect can also be obtained with printed wiring boards made of any base material.
[0106] According to the third embodiment, it is possible to facilitate the insertion of leads into through holes and to prevent misalignment of components.
[0107] Furthermore, since the through holes can be formed using a drilling device, an increase in costs can be prevented.
[0108] A printed wiring board according to a fourth embodiment will be described with reference to FIG.
[0109] The fourth embodiment is an example in which an insertion-type component 701 is mounted on an end portion of a printed wiring board 100. In the fourth embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.
[0110] FIG. 9 is a cross-sectional view and a top view showing an example of a printed wiring board according to a fourth embodiment.
[0111] The insertion type component 701 includes two leads 702. The leads 702 have a flat cross section, and are arranged in the insertion type component 701 so that the longitudinal directions of the cross sections of the leads 702 are in the same direction.
[0112] Printed wiring board 100 has through holes 404 and 405 at positions where leads 702 of insertion-type component 701 are inserted, respectively.
[0113] Through holes 404 and 405 are formed by cutting out a U-shape at an end of printed wiring board 100. Through hole 404 is a roughly oval shape whose short-side length is the short-side length of lead 702 + clearance value × 2. Through hole 405 is a roughly circular shape whose diameter is the long-side length of lead 702 + clearance value × 2.
[0114] By combining through hole 404 and through hole 405, through hole 404 suppresses the misalignment of lead 702 in the short direction indicated by arrow 911, and through hole 405 suppresses the misalignment of lead 702 in the long direction indicated by arrow 910, thereby suppressing the positional misalignment of insertion type component 701.
[0115] Furthermore, the through holes 404 and 405 are formed to have a size that allows clearance for the lengths of the leads 702 in the short and long directions, respectively, so that the leads can be easily inserted into the through holes.
[0116] Furthermore, since through holes 404 and 405 are formed by cutting out the end of printed wiring board 100 in a U-shape, insertion-type component 701 can be mounted on the end of printed wiring board 100 .
[0117] In this embodiment, a flat cross-sectional shape of the lead 702 is taken as an example, but this embodiment can be applied to any lead shape such as a wave shape or an oval shape.
[0118] In addition, in this embodiment, a combination of an approximately oval through hole and an approximately circular through hole is given as an example, but any shape of through hole may be combined as long as the shape of the through hole is expected to prevent misalignment according to the lead shape.
[0119] Furthermore, in this embodiment, the shape of one through hole is the same in all layers of the printed wiring board 100, but the shape may be different between the outer layer and the inner layer.
[0120] In this embodiment, the lands on the outer surface of the printed wiring board 100 are represented as U-shaped, but the lands may have any shape.
[0121] Although a four-layer printed wiring board is used as an example in this embodiment, the present invention may be applied to a multi-layer printed wiring board or a single-sided printed wiring board. The same effect can also be obtained with printed wiring boards made of any base material.
[0122] According to the fourth embodiment, it is possible to facilitate the insertion of leads into through holes and to prevent misalignment of components, and it is also possible to mount insertion-type components on the edge of a printed wiring board.
[0123] Furthermore, since the through holes can be formed using a drilling device, an increase in costs can be prevented.
[0124] The printed wiring board of Example 5 will be described with reference to FIGS. 10A and 10B.
[0125] The fifth embodiment is an example in which an insertion-type component 701 having protrusions on leads 702 is mounted on a printed wiring board 100. In the fifth embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.
[0126] FIG. 10A is a cross-sectional view and a top view showing an example in which a lead having a protruding shape is inserted into a circular through-hole of a size recommended by the manufacturer.
[0127] The insertion type component 701 has two leads 702. Each lead 702 has a protrusion 703 for fixing the lead 702 to the inner wall 101 of the circular through hole 102. At the position where the protrusion 703 is provided, the lead 702 has a flat cross section, and is arranged in the insertion type component 701 so that the longitudinal directions of the cross sections of the respective leads 702 are in the same direction.
[0128] Therefore, when the lead 702 is inserted into the circular through-hole 102 of the size recommended by the manufacturer, the inner wall 101 of the circular through-hole 102 and the protrusion 703 may interfere excessively, causing the lead 702 to bend in a V-shape.
[0129] FIG. 10B is a cross-sectional view and a top view showing an example of a printed wiring board according to a fifth embodiment.
[0130] The printed wiring board 100 has an oval through-hole 402 and a circular through-hole 102 at positions where two leads 702 of an insertion-type component 701 are inserted, respectively.
[0131] By combining the oval through hole 402 and the circular through hole 403, the oval through hole 402 suppresses the misalignment of the lead 702 in the short direction indicated by the arrow 911, and the circular through hole 403 suppresses the misalignment of the lead 702 in the long direction indicated by the arrow 910, thereby suppressing the positional misalignment of the insertion type component 701.
[0132] Moreover, the oval through-hole 402 and the circular through-hole 403 are formed to a size that allows clearance for the lengths of the leads 702 in the short and long directions, respectively, so that the leads can be easily inserted into the through-holes.
[0133] Moreover, excessive interference of the protrusions 703 of the leads 702 with the inner wall 101 of the through-hole is reduced, and the leads 702 can be prevented from bending in a V-shape.
[0134] Although the present embodiment has been described with reference to a lead having a protruding shape, the present embodiment can be applied to any lead shape, such as a dogleg shape or a wave shape.
[0135] Furthermore, in this embodiment, a combination of an oval through hole and a circular through hole is given as an example, but any shape of through hole may be combined as long as the shape of the through hole is expected to prevent misalignment according to the lead shape.
[0136] Furthermore, in this embodiment, the shape of one through hole is the same in all layers of the printed wiring board 100, but the shape may be different between the outer layer and the inner layer.
[0137] In this embodiment, the lands on the outer surface of the printed wiring board 100 are represented as circles, but the lands may have any shape.
[0138] Although a four-layer printed wiring board is used as an example in this embodiment, the present invention may be applied to a multi-layer printed wiring board or a single-sided printed wiring board. The same effect can also be obtained with printed wiring boards made of any base material.
[0139] According to the fifth embodiment, it is possible to facilitate the insertion of leads having a protruding shape into through holes and also to prevent misalignment of components.
[0140] Furthermore, since the through holes can be formed using a drilling device, an increase in costs can be prevented.
[0141] The printed wiring board of Example 6 will be described with reference to FIG.
[0142] Example 6 is an example of a printed wiring board having non-through holes whose inner walls are not copper-plated. In Example 6, the same components as in Example 1 are denoted by the same reference numerals, and the description thereof will be omitted.
[0143] FIG. 11 is a cross-sectional view and a top view showing an example of a printed wiring board according to a sixth embodiment.
[0144] The insertion type component 701 has four leads 702 arranged in a row. The leads 702 have a flat cross section and are arranged in the insertion type component 701 so that the longitudinal direction of the cross section of each lead 702 is in the same direction.
[0145] The printed wiring board 100 has an oval hole 406 and a circular hole 407 at positions where the leads 702 at both ends of the insertion type component 701 are inserted, and circular through holes 403 at positions where the other leads 702 are inserted.
[0146] The oval hole 406 and the circular hole 407 are non-through holes whose inner walls are not copper-plated and which do not have lands around them on the outer surface of the printed wiring board 100. The oval hole 406 has a short-side length of the short-side length of the lead 702 plus 2 times the clearance value. The circular hole 407 has a diameter of the long-side length of the lead 702 plus 2 times the clearance value.
[0147] By combining the oval hole 406 and the circular hole 407, the oval hole 406 suppresses the misalignment of the lead 702 in the short direction indicated by the arrow 911, and the circular hole 407 suppresses the misalignment of the lead 702 in the long direction indicated by the arrow 910, thereby suppressing the positional misalignment of the insertion type component 701.
[0148] Moreover, the oval hole 406 and the circular hole 407 are formed to a size that allows clearance for the short and long lengths of the lead 702, respectively, so that the lead can be easily inserted into the through hole.
[0149] In this embodiment, the ends are formed as oval holes 406 and circular holes 407, and the others are formed as circular through holes 403, but the order in which the holes or through holes are arranged is not limited to this, and any combination of oval holes or through holes and circular holes or through holes will do.
[0150] In addition, in this embodiment, an insertion type component 701 having four leads 702 arranged in a row is given as an example, but the number and arrangement of the leads are not limited to this, and the insertion type component may have multiple rows of leads.
[0151] Furthermore, in this embodiment, a flat cross-sectional shape of the lead 702 is taken as an example, but this embodiment can be applied to any lead shape such as a wave shape or an oval shape.
[0152] Furthermore, in this embodiment, a combination of oval and circular through holes or holes is given as an example, but any shape of through holes or hole combination may be used as long as the shape of the through holes or holes is such that they can be expected to prevent misalignment according to the lead shape.
[0153] Furthermore, in this embodiment, the shape of one through hole or hole is the same in all layers of the printed wiring board 100, but the shape may be different between the outer layer and the inner layer.
[0154] In this embodiment, the lands on the outer surface of the printed wiring board 100 are represented as circles, but the lands may have any shape.
[0155] Although a four-layer printed wiring board is used as an example in this embodiment, the present invention may be applied to a multi-layer printed wiring board or a single-sided printed wiring board. The same effect can also be obtained with printed wiring boards made of any base material.
[0156] According to the sixth embodiment, it is possible to facilitate the insertion of leads into non-through holes and to prevent misalignment of components.
[0157] Furthermore, since the non-through holes can be processed using a drilling device, an increase in costs can be prevented.
[0158] The printed wiring board of Example 7 will be described with reference to FIG.
[0159] Example 7 is an example of a printed wiring board in which two oval through holes of different sizes are combined. In Example 7, the same components as in Example 1 are given the same reference numerals, and the description thereof will be omitted.
[0160] FIG. 12 is a cross-sectional view and a top view showing an example of a printed wiring board according to a seventh embodiment.
[0161] The insertion type component 701 includes two leads 702. The leads 702 have a flat cross section, and are arranged in the insertion type component 701 so that the longitudinal directions of the cross sections of the leads 702 are in the same direction.
[0162] Printed wiring board 100 has oval through holes 402 and 408 at positions where two leads 702 of insertion-type component 701 are inserted, respectively. Oval through hole 408 has an oval shape whose short-side length is the length of lead 702 in the long-side direction plus twice the clearance value.
[0163] By combining the oval through hole 402 and the oval through hole 408, the oval through hole 402 suppresses the misalignment of the lead 702 in the short direction indicated by the arrow 911, and the oval through hole 408 suppresses the misalignment of the lead 702 in the long direction indicated by the arrow 910, thereby suppressing the positional misalignment of the insertion type component 701.
[0164] Moreover, the oval through holes 402 and 408 are formed to a size that allows clearance for the short and long lengths of the leads 702, respectively, so that the leads can be easily inserted into the through holes.
[0165] In this embodiment, a flat cross-sectional shape of the lead 702 is taken as an example, but this embodiment can be applied to any lead shape such as a wave shape or an oval shape.
[0166] Furthermore, in this embodiment, a combination of oval through holes is taken as an example, but any shape of through holes may be combined as long as the combination of through holes is shaped to match the lead shape and can be expected to prevent misalignment.
[0167] Furthermore, in this embodiment, the shape of one through hole is the same in all layers of the printed wiring board 100, but the shape may be different between the outer layer and the inner layer.
[0168] In this embodiment, the lands on the outer surface of the printed wiring board 100 are represented as circles, but the lands may have any shape.
[0169] Although a four-layer printed wiring board is used as an example in this embodiment, the present invention may be applied to a multi-layer printed wiring board or a single-sided printed wiring board. The same effect can also be obtained with printed wiring boards made of any base material.
[0170] According to the seventh embodiment, it is possible to facilitate the insertion of the leads into the through holes and to prevent misalignment of the components.
[0171] Furthermore, since the through holes can be formed using a drilling device, an increase in costs can be prevented.
[0172] The present invention is not limited to the above-described embodiments, but includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.
[0173] 100... printed wiring board, 203, 204, 205... substrate, 402... oval through hole, 403... circular through hole, 701... insertion type component, 702... lead
Claims
1. A printed wiring board on which a component having at least two leads is mounted, the printed wiring board having at least two holes into which the leads are respectively inserted, the holes comprising: at least one first hole whose length in one direction is the length of the lead in said one direction plus a predetermined clearance value; and at least one second hole whose length in a direction perpendicular to said one direction is the length of the lead in the direction perpendicular to said one direction plus a predetermined clearance value.
2. A printed wiring board as claimed in claim 1, wherein the leads have a flat cross section and are arranged on the component so that the longitudinal direction of the cross section of each of the leads is in the same direction, the first hole has a length in the one direction which is the short side length of the cross section of the lead plus a specified clearance value, and the second hole has a length in the direction perpendicular to the one direction which is the longitudinal length of the cross section of the lead plus a specified clearance value.
3. A printed wiring board as claimed in claim 2, wherein the first hole is an ellipse whose length in the one direction is the length of the short side of the cross section of the lead plus a specified clearance value, and the second hole is a circle whose diameter is the length of the long side of the cross section of the lead plus a specified clearance value.
4. A printed wiring board as claimed in claim 2, wherein the first hole is an ellipse whose length in the one direction is the short-side length of the cross section of the lead plus a specified clearance value, and the second hole is an ellipse whose length in the direction perpendicular to the one direction is the long-side length of the cross section of the lead plus a specified clearance value.
5. A printed wiring board according to claim 2, wherein at least one of said holes is formed by cutting out an end of said printed wiring board in a U-shape.
6. A printed wiring board according to claim 2, wherein at least one of said holes has an inner wall plated with copper.
7. A printed wiring board according to claim 2, wherein at least one of said holes has an inner wall that is not copper plated.
Citation Information
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