JP2018129393A - Printed board and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed board having a land shape which reduces a short failure caused by scraping a land in a circumferential direction.SOLUTION: A printed board 100 attached to an electronic device by a screw penetrating a mounting hole 10 includes lands 20 made of metal, which are divided into a plurality of parts which are electrically connected to each other by contact of the bearing surface of the screw head of the screw, and in a division land 30 included in the plurality of divided lands, a metal-formed portion 32 and a metal-not-formed portion 31 are alternately provided in the circumferential direction equal to or less than the maximum radius (42) of the bearing surface.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a printed circuit board and an electronic apparatus including the printed circuit board.

  Conventionally, when attaching a printed circuit board to an electronic device or the like with a fixing tool such as a screw, a technique for easily confirming that the fixing tool is attached in a predetermined manner is known. For example, Patent Document 1 discloses a printed circuit board that allows easy confirmation of mounting and fixing of a printed circuit board to a cradle or the like. In this printed circuit board, a plurality of lands are formed around the fixing hole for mounting the printed circuit board, and when the printed circuit board is mounted and fixed to the cradle by the fixing tool, the plurality of lands are connected via the fixing tool, and the continuity test circuit When a printed circuit board or the like is fixed to the cradle with a fixing tool such as a screw, the lands divided into a plurality of parts are electrically connected via the screw or the like. Thereby, it can be easily confirmed whether or not a fixture such as a screw is attached to the cradle as prescribed by conduction or non-conduction.

  Patent Document 2 discloses an electronic device including a printed circuit board that detects that the printed circuit board is fixedly held to the housing by screwing in the electronic device in which the printed circuit board is fixed to the housing by screwing. Disclose the device. This electronic device is a device of an electronic device in which a printed circuit board is fixedly held to a casing by screwing. When the board is fixedly held by screwing, the screws are connected to each other by a line. Includes a series circuit that is in a conductive state and is in a non-conductive state when the substrate is not fixedly held by screwing. This series circuit is provided with two through holes, and a closed circuit is formed by bringing a measurement terminal for measuring the conduction state into contact with these through holes. The casing includes a through hole through which the measurement terminal passes. The measurement terminal is brought into contact with the through hole through the through hole. Thereby, this electronic device enables efficient assembly.

  Further, Patent Document 3 increases the reliability of a device using the printed circuit board by establishing a screw-fixing land structure that ensures reliable electrical conduction between the screw-fixing land and the mounting screw. The structure of the screwing land when screwing the printed circuit board for the purpose is disclosed. In this structure, a printed circuit board on which electrical wiring is patterned is screwed to a member to be attached, and the electrical wiring of the printed circuit board and the member to be attached are electrically connected via the attachment screw. A solder resist layer is provided so as to be dispersed and exposed in spots.

Japanese Patent Laid-Open No. 05-160529 JP 2002-158467 A Japanese Utility Model Publication No. 05-090983

However, the screw head bearing surface, which is the part where the screw that fixes the printed circuit board to the electronic device contacts the printed circuit board, may be burred during the manufacturing process. The lands are shaved in the circumferential direction, and the shavings cause a failure that shorts the wiring on the printed circuit board.
The present invention provides a printed circuit board having a land shape that reduces a short circuit failure caused by a land being shaved in the circumferential direction, and an electronic apparatus including the printed circuit board.

In order to solve the above-mentioned problem, a printed circuit board that is attached to an electronic device by a screw that penetrates the attachment hole, and is formed of a metal that is divided into a plurality of parts that are electrically connected to each other when the seating surface of the screw head contacts. One divided land constituting a land divided into a plurality of lands is provided with a portion in which a metal is formed and a portion in which a metal is not formed alternately in a circumferential direction that is equal to or less than the maximum radius of the seating surface. A printed circuit board is provided.
According to this, since the metal divided land has the non-metal portion in the circumferential direction on the seat surface of the screw head, it can be easily confirmed that the screw is attached as prescribed, and the screw head seat. The portion that can be scraped off by the surface is reduced, and even if it is scraped off, the amount and size thereof are reduced, and a printed circuit board that reduces short-circuit failure can be provided.

Furthermore, the portions in contact with the seating surface in the divided lands may be connected to each other in the circumferential direction having a radius larger than the maximum radius of the seating surface.
According to this, the metal of the divided land is difficult to peel off.

Further, the number of divided lands provided around one mounting hole may be three or more.
According to this, it is possible to easily confirm that the screw is attached with an inclination as well as the presence or absence of the screw and insufficient attachment.

In order to solve the above-described problems, an electronic apparatus including the printed circuit board is provided.
According to this, it is possible to provide an electronic device including a printed circuit board that reduces a short circuit failure.

  ADVANTAGE OF THE INVENTION According to this invention, the printed circuit board which has a land shape which reduces the short circuit failure which arises when a land is shaved in the circumferential direction, and an electronic device provided with the printed circuit board can be provided.

1 is a schematic perspective view of a printed circuit board according to a first embodiment of the present invention. The cross-sectional schematic diagram around the land part of the printed circuit board of 1st Example which concerns on this invention. The schematic diagram which shows the land shape in the printed circuit board of the 1st Example which concerns on this invention. The schematic diagram which shows the trace by which the land in the printed circuit board of the 1st Example which concerns on this invention was scraped off. (A1) Schematic diagram showing the land shape on the printed circuit board of the second embodiment, (A2) Schematic diagram showing the scraped trace of the land on the printed circuit board of the second embodiment, (B1) third. Schematic diagram showing the land shape on the printed circuit board of the example, (B2) Schematic diagram showing the scraped trace of the land on the printed circuit board of the third example, (C1) showing the land shape on the printed circuit board of the fourth example. Schematic diagram, (C2) Schematic diagram showing traces of lands on the printed circuit board of the fourth embodiment. The schematic diagram which shows the land shape in the printed circuit board of 5th Example which concerns on this invention. The schematic diagram which shows the land shape in the conventional printed circuit board.

Hereinafter, each embodiment will be described with reference to the drawings.
<First Example>

  With reference to FIG. 1 and FIG. 2, a printed circuit board 100 and an electronic device 200 including the printed circuit board 100 in this embodiment will be described. The printed circuit board 100 has a plurality of mounting holes 10 through which the screws 40 pass, and is screwed and fixed to the plurality of screwing bosses 201 formed in the electronic device 200 by the screws 40. The electronic device 200 uses an electronic circuit mounted on the printed circuit board 100. For example, a device using the electronic circuit, such as an electronic device mounted on a computer, an automobile control device, a television, or a machine tool. General.

  The printed circuit board 100 has lands 20 patterned with metal on the surface in the vicinity of each mounting hole 10. The land 20 includes a divided land 30 divided into two. That is, the divided lands 30 divided into two are not electrically connected to each other without the screw 40.

  Further, the printed circuit board 100 has two inspection lands 50 for each mounting hole 10 patterned with metal connected to the respective divided lands 30. The inspection land 50 is for inspecting whether the printed circuit board 100 is securely attached, and is an inspection land for inspecting whether or not the screw 40 is in contact with the divided land 30 without floating. When the screw 40 is in contact with the divided land 30 without being floated, they are electrically connected to each other.

  The split land 30 comes into contact with the seat surface 43 of the screw head 41 of the screw 40 when the screw portion of the screw 40 is inserted into the boss portion 201 and screwed. The divided lands 30 divided into two are electrically connected to each other through a metal seat surface 43. In this state, when the continuity is inspected by the inspection land 50, they are electrically connected to each other, so that it can be confirmed that the printed circuit board 100 is attached without the screws 40 floating.

  The shape of the divided land 30 in the present embodiment will be described with reference to FIG. 3. Prior to that, the conventional divided land 30Z will be described with reference to FIG. The divided land 30 </ b> Z is formed by being divided into two concentric circles with a predetermined width around the mounting hole 10. In addition, an inspection land 50 that is brought into contact with a probe of a continuity inspection device is formed from each divided land 30Z. Usually, the split land 30Z is in contact with the seating surface 43 of the screw 40, so that the outer periphery is larger than the outer edge 42 of the screw head 41 that is the outermost side of the seating surface 43 from the inner periphery slightly larger than the radius of the mounting hole 10. It is formed with a width of up to.

  Generally, burrs may be formed in the manufacturing process in the seating surface 43 of the screw head 41 and the outer edge 42 of the screw head 41, which are portions where the screw 40 contacts the divided land 30Z. Therefore, as shown in FIG. 7, in the process of tightening the screw 40, the split land 30Z formed of copper by the burr may be scraped in the circumferential direction. This figure shows the trace SC scraped off from one of the divided lands 30Z. The metal in the portion of the trace SC that has been scraped off in this way becomes scraped and causes a failure that shorts the wiring on the printed circuit board. The larger the size of the scraped trace SC, the higher the possibility of shorting the wiring.

  As shown in FIG. 3, each of the divided lands 30 is not formed with a metal pattern, and a non-metal in which a resist film is formed on a portion of the printed board 100 where the insulating plate is exposed or on the insulating plate. A large number of portions 31 are arranged on the circumference. The non-metal portion 31 on the seat surface 43 exists on the inner peripheral side (the mounting hole 10 side) from the outer edge 42 of the screw head 41. As a result, each of the divided lands 30 is formed so as to have the non-metallic portion 31 on the seating surface 43 in the circumferential direction not more than the maximum radius of the seating surface 43 that is the outer edge 42 of the screw head 41. 43, the non-metal portions 31 and the metal portions 32 are alternately arranged.

  In this way, when the divided lands 30 are formed on the seating surface 43 so that the non-metal portions 31 and the metal portions 32 are alternately present, as shown in FIG. 4, the scraped marks SC shown in FIG. Even if it is cut off in the same way, the metal to be cut off is about half of the area in this embodiment. Furthermore, since the size of one piece of metal to be scraped is the size of the metal portion 32 sandwiched between the non-metal portions 31, it is smaller than the size of the metal to be scraped in the conventional split land 30Z. .

  As described above, since the metal divided land 30 has the non-metal portion in the circumferential direction on the seating surface 43 of the screw head 41, it can be easily confirmed that the screw 40 is attached in a predetermined manner without floating. At the same time, the portion that can be scraped off by the seating surface 43 of the screw head 41 is reduced, and even if the portion is scraped off, the amount and size thereof are reduced, and the printed circuit board 100 that reduces short-circuit failure can be provided.

  Each of the divided lands 30 has a connecting portion 33 that connects portions that contact the seating surface 43 to each other in the circumferential direction having a radius larger than the maximum radius of the seating surface 43 that is the outer edge 42 of the screw head 41. By connecting the metal part 32 to the seating surface 43, the metal of the metal part 32 of the divided land 30 is difficult to peel off.

<Second Example>
With reference to FIG. 5 (A1) and (A2), the division | segmentation land 30A based on a present Example provided in a printed circuit board is demonstrated. In order to avoid duplication of explanation, points different from the above embodiment will be mainly described. Although the inspection lands are omitted in the drawing, it is assumed that the inspection lands are formed on each of the divided lands. The divided land 30 </ b> A is divided into two in the vicinity of the mounting hole 10. Each of the divided lands 30A is formed so that peaks and valleys appear alternately on the inner peripheral side and the outer peripheral side over almost a half circumference, and a portion with a large radius and a small portion are alternately linear from the center of the mounting hole 10. It is formed to change. The outer edge 42 of the screw head 41 is formed so as to be outside the crest portion on the outer peripheral side. As described above, the divided land 30A has the non-metal portions 31A on the seat surface 43 in the circumferential direction not more than the maximum radius of the seat surface 43, that is, the non-metal portions 31A and the metal portions 32A are alternately arranged on the seat surface 43. Is formed.

  If the non-metal portions 31A and the metal portions 32A are alternately formed on the seating surface 43, even if the non-metal portions 31A and the metal portions 32A are scraped as shown in FIG. The size of one fragment becomes smaller. As a result, a short circuit failure can be reduced. Further, since the divided land 30A is redundantly formed as a double annular metal portion 32A on the inner peripheral side and the outer peripheral side, for example, when one burr is generated near the center of the seating surface 43. However, since the annular metal portion 32A on the inner peripheral side is not affected, the annular metal portion 32A on the outer peripheral side is not affected. be able to.

<Third embodiment>
With reference to FIG. 5 (B1) and (B2), the division | segmentation land 30B which concerns on a present Example provided in a printed circuit board is demonstrated. The divided land 30 </ b> B is divided into two in the vicinity of the mounting hole 10. Each of the divided lands 30B includes a plurality of radial portions formed radially from the vicinity of the mounting hole 10 to the outer peripheral side, and a connection portion 33B that connects these radial portions on the outer peripheral side. The plurality of radial portions are metal portions 32 </ b> B on the seat surface 43, and the non-metal portions 31 </ b> B are on the seat surface 43 between the radial portions. The connecting portion 33B connects the radial portions outside the outer edge 42 of the screw head 41. As described above, the divided land 30B has the non-metal portions 31B on the seat surface 43 in the circumferential direction not more than the maximum radius of the seat surface 43, that is, the non-metal portions 31B and the metal portions 32B are alternately arranged on the seat surface 43. Is formed.

  If the non-metal portions 31B and the metal portions 32B are alternately formed on the seating surface 43, even if the metal is scraped off as shown in FIG. The size of one fragment becomes smaller. As a result, a short circuit failure can be reduced.

<Fourth embodiment>
With reference to FIG. 5 (C1) and (C2), the division | segmentation land 30C which concerns on a present Example provided in a printed circuit board is demonstrated. The divided land 30 </ b> C is divided into two in the vicinity of the mounting hole 10. Each of the divided lands 30C is formed such that a bent portion that is bent from the inner peripheral side to the outer peripheral side and a bent portion that is bent from the outer peripheral side to the inner peripheral side appear alternately and continuously over almost a half circumference. A portion having a large radius and a portion having a small radius from the center of 10 are alternately changed in a curved line. The outer edge 42 of the screw head 41 is formed in the vicinity where a bent portion bent from the inner peripheral side to the outer peripheral side and a bent portion bent from the outer peripheral side to the inner peripheral side are connected. As described above, the divided land 30C has the non-metal portions 31C on the seat surface 43 in the circumferential direction not more than the maximum radius of the seat surface 43, that is, the non-metal portions 31C and the metal portions 32C are alternately arranged on the seat surface 43. Is formed.

  If the non-metal portions 31C and the metal portions 32C are alternately formed on the seating surface 43, even if the non-metal portions 31C and the metal portions 32C are cut as shown in FIG. The size of one fragment becomes smaller. As a result, a short circuit failure can be reduced.

<Fifth embodiment>
With reference to FIG. 6, the division | segmentation land 30D which concerns on a present Example provided in a printed circuit board is demonstrated. The divided land 30 </ b> D is divided into four in the vicinity of the mounting hole 10. Each divided land 30 </ b> D is formed so that peaks and valleys alternately appear on the inner circumference side and the outer circumference side over almost a quarter of the circumference, and a portion having a large radius and a portion having a small radius from the center of the mounting hole 10. It is formed to change linearly alternately. The outer edge 42 of the screw head 41 is formed so as to be outside the crest portion on the outer peripheral side. Thus, the split land 30D has the non-metal portions 31D on the seat surface 43 in the circumferential direction not more than the maximum radius of the seat surface 43, that is, the non-metal portions 31D and the metal portions 32D are alternately arranged on the seat surface 43. Is formed. If the non-metal portions 31D and the metal portions 32D are alternately formed on the seating surface 43, even if scraped off, the scraped metal becomes smaller in area, and the size of one piece of scraped metal becomes smaller. . As a result, a short circuit failure can be reduced.

  Further, since the divided land 30D is redundantly formed as a double annular metal portion 32D on the inner peripheral side and the outer peripheral side, for example, when one burr is generated near the peripheral edge of the seating surface 43. However, since the annular metal portion 32D on the outer peripheral side is not affected, the annular metal portion 32D on the inner peripheral side is not affected, so that it is confirmed that the screw 40 is securely attached as it is without floating. be able to.

  Also, inspection lands 501/502/503/504 are formed from the four divided lands 30D so as to be in contact with the probes of the continuity inspection device. When the screw 40 is tilted and attached to the boss portion 201, for example, when the screw head 41 is tilted and attached to the inspection lands 501 and 502, the inspection land 501 and the inspection land 502 are electrically connected. The inspection land 503 and the inspection land 504 are not conductive. Therefore, in the case of being divided into three or more around the mounting hole 10 as in the divided land 30D, the screw is obtained by inspecting with a plurality of pairs of inspection lands 501/502/503/504. It is possible to easily confirm that the screw 40 is attached in an inclined manner as well as the presence or absence of the attachment 40 and the insufficient attachment.

  Note that it is also conceivable that the lead lines of the inspection lands 501/502/503/504 drawn from the divided lands 30D are scraped by burrs on the seat surface 43. A through hole may be provided in the divided land 30D to form an inspection land on the back side of the printed board. Or you may form through a through hole in the front side in which the division | segmentation land is again formed from the back side in the position away from the seat surface.

  In addition, this invention is not limited to the illustrated Example, The implementation by the structure of the range which does not deviate from the content described in each item of a claim is possible. That is, although the present invention has been particularly illustrated and described with respect to particular embodiments, it should be understood that the present invention has been described in terms of quantity, quantity, and amount without departing from the scope and spirit of the present invention. In other detailed configurations, various modifications can be made by those skilled in the art.

DESCRIPTION OF SYMBOLS 200 Electronic device 201 Boss part 100 Printed circuit board 10 Mounting hole 20 Land 30 Divided land 31 Non-metal part 32 Metal part 33 Connection part 40 Screw 41 Screw head 42 Outer edge of screw head 43 Seat surface 50 Inspection land SC Scraped trace

Claims (4)

A printed circuit board that is attached to an electronic device by a screw that penetrates the mounting hole,
A land formed of metal divided into a plurality of conductors that are electrically connected to each other by contacting the bearing surface of the screw head of the screw;
One divided land constituting the plurality of divided lands includes a portion where a metal is formed and a portion where a metal is not formed alternately in a circumferential direction equal to or less than the maximum radius of the seating surface. Yes,
Printed board.   2. The printed circuit board according to claim 1, wherein portions of the divided land where the metal is formed on the seating surface are connected to each other in a circumferential direction having a radius larger than the maximum radius of the seating surface. .   The printed circuit board according to claim 1 or 2, wherein the number of the divided lands provided around one of the mounting holes is three or more. An electronic apparatus comprising the printed circuit board according to any one of claims 1 to 3.