JP4709512B2 - Electronics - Google Patents

Description

The present invention relates to an electronic device incorporating a printed wiring board.

As electronic components and electronic devices have higher functions and smaller sizes, circuit boards mounted in the devices are required to have higher density and smaller size. As a pattern forming technique for a printed wiring board for increasing the mounting circuit density of this kind of circuit board, various board techniques such as a technique for preventing a solder bridge when the pattern interval is narrowed have been proposed.
JP-A-9-307220

  There is a restriction on the arrangement position of the pads in the vicinity of the board end of the printed wiring board as a problem in restrictions in the design of the printed wiring board. When the pads are arranged near the end of the printed wiring board, if the arranged pads are too close to the end of the board, it becomes difficult to form a solder resist. For this reason, the arrangement | positioning of a pad was permitted on condition that the area | region which can form a soldering resist is ensured. Specifically, the distance from the edge of the board to the pad and the solder resist so as not to cause problems such as a short circuit due to the peeling of the solder resist when the board that has undergone the solder resist process is cut into a printed wiring board alone There was a restriction on the minimum width. This restriction has been one factor that hinders pattern formation for high-density mounting.

The present invention has been made in view of the above circumstances, and allows the placement of pads in the vicinity of the board edge where the solder resist width is not sufficiently secured, and allows the pads to be arranged in the vicinity of the board edge, thereby enabling high-density circuit mounting. It is an object of the present invention to provide an electronic device incorporating a printed wiring board that enables the above.

The present invention includes a housing and a printed wiring board accommodated in the housing, and the printed wiring board is provided with a solder resist from one side edge of the printed wiring board on a surface on which the pattern of the printed wiring board is provided. Prohibition of the formation of the pattern and solder resist formed between the pad located at a distance where the width is not sufficiently secured and the side where the pattern is provided from one side edge of the pad to one side edge A prohibited area , a solder resist that is provided outside the pad , the pad periphery , and the prohibited area, and has a portion in contact with the one side edge of the surface on which the pattern is provided, and a circuit component mounted on the pad An electronic device having the above-mentioned features .

  The placement of pads near the board edge where the solder resist width is not sufficiently secured is allowed, and high-density circuit mounting is possible with the pads arranged closer to the board edge.

  In the present invention, when a pad is placed near the end of a printed wiring board, the board end side of the pad is used as a pattern-prohibited area, so that there is a problem such as a circuit short circuit after mounting circuit components without forming a solder resist. In the following, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows an example of the pattern arrangement of the main part in the pattern layout of the printed wiring board according to the embodiment of the present invention. The pattern arrangement configuration shown in FIG. 1 is such that when the pair of pads 12a and 12b for mounting the circuit component 15 is formed in the vicinity of the plate end 10e of the printed wiring board 10, the plate ends of the pair of pads 12a and 12b are formed. The area from the side end to the plate end 10e is defined as pattern prohibition areas 13a and 13b. As a result, pattern formation is prohibited from the end of the pair of pads 12a, 12b to the end 10e of the pair of pads 12a, 12b, and the pattern prohibition areas 13a, 13b are areas where the solder resist 11 is not covered and the solder resist 11 is not covered. Thus, the pair of pads 12a and 12b can be arranged close to the plate end side where a sufficient solder resist width cannot be formed on the plate end side. In this way, it is possible to place pads near the board edge where the solder resist width is not sufficiently secured by specifying the pattern prohibition area, and it is possible to place pads closer to the board edge, resulting in higher density. Circuit implementation is possible.

  The configuration of a printed wiring board design CAD system capable of realizing a pattern layout in which a pattern prohibition area is interposed between the board edge and the pad as shown in FIG. 1 is shown in FIG. 2, and the printed wiring board according to the pattern layout is shown in FIG. FIG. 3 shows the manufacturing process of FIG. 3, and FIG. 4 shows the processing procedure of the main part of the pattern layout in the printed wiring board design CAD system shown in FIG.

  The printed wiring board design CAD system 20 shown in FIG. 2 includes a control unit 21, a storage unit 22, an operation input unit 23, and a display unit 24.

  The control unit 21 has a program processing function and controls the entire CAD system 20. In this embodiment, the display unit 24 is displayed and controlled according to the contents input by the user (pattern designer) operating the operation input unit 23, and the printed wiring board design in the pattern layout module 23a stored in the storage unit 22 is controlled. The process as shown in FIG. 4 is executed according to the part placement process routine including the rule, and the pattern layout function is provided in which the pattern prohibition area is interposed between the plate edge and the pad as described above. In this process, the mounting component information table 23b stored in the storage unit 22 is referred to obtain information such as the shape and dimensions of the component mounting pads placed on the printed wiring board, and based on the acquired information. A process of placing a component mounting pad on the printed wiring board is also included.

  The storage unit 22 stores various programs executed by the control unit 21 and various information for pattern design and component mounting. In this embodiment, a pattern layout module 23a having a component placement processing routine including a printed wiring board design rule as shown in FIG. 4 and a mounted component information table 23b that is referred to when placing a component mounting pad. Etc. are stored.

  The operation input unit 23 and the display unit 24 are used for various inputs and confirmations in the pattern layout of the printed wiring board. In this embodiment, the board end and the pad as shown in FIGS. 1 and 4 are used. It is used for input, confirmation, etc., when placing a component mounting pad with a pattern prohibited area in between.

  FIG. 3 shows a case where the layout of a printed wiring board allows the placement of component mounting pads near the board end with a pattern prohibition area interposed between the board edge and the pad as shown in FIG. The manufacturing process of the printed wiring board of is shown. In the wiring board design process 301, as described above, when a component mounting pad is placed near the board end of the printed wiring board, the solder resist width is not sufficiently secured between the board end and the pad placement portion. The arrangement of pads in the vicinity of the plate edge is allowed by designating a pattern prohibition area. In the printed wiring board manufacturing process, in the pattern forming process 302 by pattern etching, the copper foil is peeled off from the pattern prohibited area, and no pattern is formed in the area. In the solder resist process 303, no solder resist is formed on the pattern prohibited area. In the surface treatment step 304, final surface processing is performed including the pattern prohibited area.

  FIG. 4 shows a processing procedure of the control unit 21 according to a component placement processing routine including a printed wiring board design rule in the pattern layout module 23 a stored in the storage unit 22. In this process, with respect to the pattern check in the vicinity of the board edge, the distance between the board edge of the pad arranged on the printed wiring board and the board edge (hereinafter referred to as the pattern gap (A)), the print Check whether it is necessary to specify the pattern prohibition area for each solder resist width (hereinafter referred to as the minimum resist remaining width (B)) that can be formed between the pads placed on the wiring board and the board edge. (See steps S42 to S46), but not limited to this, it is checked whether or not it is necessary to designate a pattern prohibited area for either the pattern gap (A) or the minimum resist remaining width (B). The processing form to perform may be sufficient. For example, a processing form for checking whether or not it is necessary to specify a pattern prohibition area for only the resist minimum remaining width (B) may be used. Further, regarding the designation of the pattern prohibited area, when the pattern gap (A) check and the resist minimum remaining width (B) check are not satisfied, the minimum allowable width determined by the rule is not satisfied (No in steps S44 and S46). (Refer to step S48) and display the fact on the display unit 24 to notify the user (see step S48), and in accordance with the user instruction, the pattern prohibition area is interposed, but the pattern prohibition area does not require the user instruction. Or a processing mode in which the user is informed without waiting for an instruction from the user. In FIG. 4, the minimum permissible width of the pattern gap (A) determined by the rule and the minimum permissible width of the minimum resist remaining width (B) are different, but the same width (value) may be used. .

  In the process shown in FIG. 4, it is detected that the pair of pads 12a, 12 for mounting the circuit component 15 is placed within a predetermined area from a preset board end of the printed wiring board to be subjected to pattern layout. When it is done (S41, S42 Yes), it is checked whether or not the pattern gap (A) shown in FIG. 4 satisfies the set minimum allowable width (step S43). For example, if the pattern gap (A) exceeds 0.25 mm, it is determined that the set minimum allowable width is satisfied, and if it is 0.25 mm or less, it is determined that the minimum allowable width is not satisfied.

  Here, if the pattern gap (A) satisfies the minimum allowable width (S44 Yes), it is subsequently checked whether or not the minimum resist remaining width (B) satisfies the set minimum allowable width (step). S45). For example, if the minimum resist remaining width (B) exceeds 0.2 mm, it is determined that the set minimum allowable width is satisfied, and if it is 0.2 mm or less, it is determined that the minimum allowable width is not satisfied.

  In the pattern gap (A) check (step S43), when the pattern gap (A) does not satisfy the minimum allowable width (No in S44), this is displayed on the display unit 24 to the user. This is notified, and the designation of the pattern prohibition area is included in the design element, and the user's instruction is waited (step S48).

  Here, if the user designates a pattern prohibition area between the pair of pads 12a and 12b and the board end 10e, the pair of pads 12a and 12b and the board end 10e placed on the printed wiring board Between these, pattern prohibition areas 13a and 13b, in which neither a pattern nor solder resist exists, are interposed, and the arrangement of the pads 12a and 12b in the vicinity of the plate edge 10e is allowed (step S49).

  In the check of the minimum resist remaining width (B) (step S45), when the minimum resist remaining width (B) satisfies the minimum allowable width (Yes in S46), the arrangement positions of the pads 12a and 12b are set. Recognizing that the pattern arrangement conforms to a normal regular rule, a pattern check other than the above check is performed (step S47).

  In the minimum resist remaining width (B) check (step S45), if the minimum resist remaining width (B) does not satisfy the minimum allowable width (No in S46), that fact is displayed on the display unit 24. The user is notified, and the designation of the pattern prohibition area is included in the design element, and the user's instruction is waited (step S48).

  Here, if the user designates a pattern prohibition area between the pair of pads 12a and 12b and the board end 10e, the pair of pads 12a and 12b and the board end 10e placed on the printed wiring board Between these, pattern prohibition areas 13a and 13b are interposed, and the arrangement of pads 12a and 12b in the vicinity of the plate end 10e is allowed (step S49).

  Such pattern layout processing is repeatedly executed until the layout is completed for the printed wiring board to be subjected to pattern layout (steps S50, S41 to S50).

  As described above, in the pattern layout process, the designation of the pattern prohibition area in the pattern arrangement in the vicinity of the board edge is included in the design element, and the distance from the board edge side end of the pair of pads 12a and 12b to the board edge 10e is included. By designating as the pattern prohibition areas 13a and 13b, the pattern formation and the solder resist 11 are prohibited during that time, so that the pair of pads 12a and 12b cannot form a sufficient solder resist width on the plate end side. Can be placed as close as possible. In this way, it is possible to place pads near the board edge where the solder resist width is not sufficiently secured by specifying the pattern prohibition area, and it is possible to place pads closer to the board edge, resulting in higher density. Circuit implementation is possible.

  FIG. 5 shows a configuration example of an electronic device mounted with a printed circuit board to which the pattern layout technique described above is applied. The electronic apparatus shown in FIG. 5 includes a disk drive unit 50 and a control circuit board 10A that controls the operation of the disk drive unit 50, which constitute a hard disk device. The disk drive unit 50 includes shells 50a and 50b serving as outer casings, a disk 52 serving as a rotational recording medium, a carriage 53 having a head for reading / writing data on the disk 52, and a voice coil motor 55 driving the carriage 53. Etc. are built in and integrated. The control circuit board 10A has a plate surface shape that matches the shape of the shell 50a of the disk drive unit 50, and is arranged in the vicinity of the plate edge via the pattern prohibition areas 13a and 13b according to the pattern arrangement shown in FIG. A pair of pads 12a and 12b are provided, and circuit components 15 for controlling the operation of the disk drive unit 50 are mounted on the pads 12a and 12b. The control circuit board 10A is designated as the pattern prohibition areas 13a and 13b from the plate end side end of the pair of pads 12a and 12b to the plate end 10e, and the pattern formation and the solder resist 11 are prohibited. The pair of pads 12a, 12b are arranged close to the plate end side where a sufficient solder resist width cannot be formed on the plate end side. As a result, high-density circuit mounting is possible, and a control circuit board 10A is realized by high-density circuit mounting that is downsized.

  FIGS. 6 and 7 show the arrangement of pads and pattern prohibited areas in the vicinity of the board end of the printed wiring board with a pattern prohibited area different in shape from the embodiment shown in FIGS. 1, 4, and 5, respectively. An example is shown. FIG. 6 shows an arrangement example in which one pattern prohibited area 13c is interposed between the pair of pads 12a and 12b along the plate end 10e and the plate end 10e. FIG. 7 shows an example of the arrangement configuration of the pattern prohibited area 13d between the board end 10e and the pads 12a and 12b when the pair of pads 12a and 12b are arranged at the corners of the printed wiring board 10 along the board end 10e. Is shown. In any of these arrangements, the pair of pads 12a, 12b cannot form a sufficient solder resist width on the plate end side in the same manner as the embodiment shown in FIG. 1, FIG. 4, and FIG. It can be arranged close to the side, and higher-density circuit mounting becomes possible.

  Note that the present invention is not limited to the above-described embodiment, and can be embodied by modifying or combining the constituent elements without departing from the scope of the invention in the implementation stage. For example, in the processing shown in FIG. 4, regarding the pattern check in the vicinity of the plate edge, it is necessary to specify the pattern prohibition area for each of the pattern gap (A) and the width of the solder resist (hereinafter referred to as the resist minimum remaining width (B)). However, the present invention is not limited to this, and a process for checking whether or not it is necessary to specify a pattern prohibited area for either the pattern gap (A) or the minimum resist remaining width (B). For example, it may be a processing mode for checking whether or not it is necessary to specify a pattern prohibition area for only the resist minimum remaining width (B). And the minimum resist remaining width (B) check satisfy the minimum allowable width determined by the rules. In this case, the processing unit displays a message to that effect on the display unit 24 and notifies the user to interpose the pattern prohibited area according to the user's instruction. However, the processing form intervenes the pattern prohibited area without requiring the user's instruction. In addition, a processing form that informs the user of this fact without waiting for the user's instruction may be used, etc. In the above embodiment, the minimum allowable width of the pattern gap (A) determined by the rule and the resist minimum Although the remaining width (B) is different from the minimum allowable width, the same width (value) may be used, and the shape and arrangement of the pads 12a and 12b and the pattern prohibited area are also described in the above embodiment. Without limitation, various changes, combinations, and the like are possible.

The figure which shows the example of pattern arrangement | positioning of the principal part of the printed wiring board which concerns on embodiment of this invention. The figure which shows the structure of the printed wiring board design CAD system which enabled manufacture of the printed wiring board which concerns on the said embodiment. The figure which shows the design and manufacturing process of a printed wiring board concerning the said embodiment. The flowchart which shows the components arrangement | positioning process procedure of the CAD system shown in the said FIG. The figure which shows the structural example of the apparatus which mounted the printed wiring board which concerns on the said embodiment. The figure which shows the modification of the pattern arrangement | positioning of the printed wiring board which concerns on the said embodiment. The figure which shows the modification of the pattern arrangement | positioning of the printed wiring board which concerns on the said embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Printed wiring board, 10e ... Board edge, 10A ... Control circuit board, 11 ... Solder resist, 12a, 12b ... Pad, 13a, 13b, 13c, 13d ... Pattern prohibition area, 15 ... Circuit component, 20 ... Printed wiring board Design CAD system, 21 ... control unit, 22 ... storage unit, 23 ... operation input unit, 23a ... pattern layout module, 23b ... mounted component information table, 24 ... display unit 24, 50 ... disk drive unit, 50a, 50b ... shell, 52 ... disk, 53 ... carriage, 55 ... voice coil motor, 301 ... wiring board design process, 302 ... pattern formation process, 303 ... solder resist process, 304 ... surface treatment process.

Claims (4)

A housing,
A printed wiring board housed in the housing;
The printed wiring board is
From one side edge of the printed wiring board on the surface on which the pattern of the printed wiring board is provided, a pad positioned at a distance where the solder resist width is not sufficiently secured ,
A prohibition area for prohibiting the formation of the pattern and the solder resist, which is formed between one side edge to one side edge of the pad on the surface on which the pattern is provided ;
Solder resist having a portion in contact with the one side edge of the surface on which the pattern is provided, as well as the pad , the pad periphery , and the prohibited area ;
Circuit components mounted on the pads;
An electronic apparatus comprising:   The electronic device according to claim 1, wherein the pads are arranged in pairs on the pattern forming surface along the one side edge, and the circuit components are mounted on the pads forming the pair.   The electronic device according to claim 1, wherein the pad is provided in a range of 0.25 mm or less from the one side edge.   The electronic device according to claim 1, wherein the prohibited area is provided when a distance between the one side edge and the pad is 0.25 mm or less.

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