JPH07326829A - Printed circuit board - Google Patents

Abstract

(57) [Summary] [Structure] This is a substantially U-shaped printed circuit board in which a plurality of conductive paths are extended from one end side to the other end side of the circuit surface. The wiring portion A which is a portion (Y portion) and the wiring portion B which is a non-control portion (X portion) of electric resistance value are provided. (Wiring portion A) In a plurality of conductive paths, by increasing the width of the conductive path of the a side portion and decreasing the width of the conductive path of the b side among the substantially U-shaped conductive paths, A wiring part in which the electric resistance values of the paths are set to be substantially the same. (Wiring portion B) In the conductive path other than the wiring section A, a wiring section in which the conductive path is set to have a predetermined width. [Effect] The present invention can be applied to a new application in which the electric resistance values of the conductive paths between the left and right terminals need to be substantially the same. Moreover, by providing the wiring portion B, the same printed circuit board can be used for different purposes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board having a wiring portion in which electric resistance values of a plurality of conductive paths are set to be substantially the same.

[0002]

2. Description of the Related Art Generally, a printed circuit board is used mainly for the purpose of connecting a certain functional section to another functional section such as a device, except for a high frequency region where the characteristic impedance of the printed circuit board affects. ing. Therefore, little consideration was given to the electric resistance value of the conductive path (wiring pattern) of the printed circuit board. In this type of printed circuit board, each conductive path is formed by arranging a plurality of wiring patterns of the same width side by side at regular intervals. Therefore, in the case of a printed circuit board having a complicated shape, for example, when the conductive paths are arranged side by side in a U shape, the electric resistance values of the conductive paths inevitably have different values. For example, when the respective conductive paths are arranged side by side to form a U-shape as a whole, the conductive path of the inner part of the U-shape and the conductive path of the outer part are
The length becomes different (the outside becomes longer), and the electric resistance value of each conductive path becomes different. That is, the conductive path at the outer portion of the U-shape becomes longer than that at the inner portion, and the resistance value becomes higher.

[0003]

However, as the applications of printed circuit boards have expanded, there has been a demand for making the electrical resistances of the conductive paths formed on the printed circuit boards the same. In response to this request, the applicant of the present application has filed an application for a printed circuit board (flexible printed circuit board) having a structure as shown in FIGS. 11 and 12 (Japanese Patent Application No. 4-12).
7383). Fifty conductive paths are formed in a U shape between e and f on the printed circuit board (the number of conductive paths is seven in the figure for simplification). In this printed circuit board, as is clear from FIGS. 11 and 12, the conductive path (circuit) of the U-shaped upper portion (e-side portion) is long and the conductive portion (f-side portion) of the lower portion is conductive. The road is getting shorter.
Then, by setting the width of the conductive path on the side of the e side large and the width of the conductive path on the side of the f side small in the spline portion, the whole of the conductive paths of this printed circuit board (shear portion, spline portion, section) is set. Section), the electric resistance values of the conductive paths are substantially the same. Further, a printed circuit board having a substantially U-shape as shown in FIG. 13 and having a greatly changed shape has been proposed. The entire printed circuit board is divided into five parts, which are the so-to-the-sheath part. Among the above parts, the toe part is a U-shaped upper part (g-side part) like the above-mentioned printed circuit board.
The width of the conductive path is set to be large, and the width of the conductive path in the lower portion (the h-side portion) is set to be small. As a result, the electric resistance values of the conductive paths become substantially the same. Further, as shown in FIG. 14, in addition to the printed circuit board having only the cable part,
A printed circuit board provided with a mounting portion (mounting land) 2 for an electronic component or an IC has been proposed. Then, the right side of the mounting land 2 is a conductive path control range portion, and the same as the printed circuit boards described above and above so as to obtain a uniform electric resistance value by combining the two portions. In, the width of the conductive path in the upper portion of the U-shape is set large, and the width of the conductive path in the lower portion is set small. In the figure, the part G is a part where power lines, signal lines, etc. coexist.
The electrical resistance value is individually specified for each conductive path a to e such as 0.5Ω or 0.2Ω. The printed circuit board shown in FIG. 15 is substantially J-shaped, and the N, N, and N portions are non-control portions of the conductive path width. Similarly, the width of the conductive path is changed to control the electric resistance to be uniform. Further, FIG. 16 shows a printed circuit board in which one conductive path makes one round trip. In such a shape, the electric resistance value is controlled to be uniform in all regions by appropriately changing the width of the conductive path n.

However, recently, the requirements for printed circuit boards have become more complex and strict, for example:
There is a demand for a printed circuit board that can be used only for one specific application and has wiring parts for different applications in the same printed circuit board. In response to such a demand, in the printed circuit board, the electric resistance values of the respective conductive paths are substantially the same, but a wiring portion used for a purpose different from the purpose of the respective conductive paths is provided. However, the fact is that a printed circuit board satisfying such requirements has not yet been developed, and its development is strongly demanded.

The present invention has been made in view of the above circumstances, and each conductive path has substantially the same electric resistance value, and further includes a wiring portion for a purpose other than the above conductive paths. The purpose is to provide a printed circuit board.

[0006]

In order to achieve the above object, the printed circuit board of the present invention has a plurality of conductive paths.
The printed circuit board extends from one end side to the other end side of the circuit surface, and has a configuration in which a wiring portion A and a wiring portion B shown below are provided. (Wiring part A) In a plurality of conductive paths, the width of at least a part of each conductive path is changed to set the electric resistance value of each conductive path whose width is changed to be substantially the same. (Wiring part B) Of the plurality of conductive paths, other than the above-mentioned wiring part A, a wiring part in which the conductive path is set to a predetermined width.

[0007]

That is, the present inventors have conducted extensive research on a specific method for making the electric resistance values of the conductive paths of the printed circuit board substantially the same. As a result, by changing the width of each conductive path, for example, when a plurality of conductive paths are arranged side by side to form a U-shape as a whole, the length of the conductive path becomes longer. The width of the conductive path is narrowed and the width of the conductive path is narrowed toward the inside of the U-shape so that the electrical resistance of each conductive path does not change without changing the overall shape of each conductive path, for example, the U-shape. It has been found that the values are substantially the same. Furthermore, in addition to the wiring portion A in which the electric resistance value of each conductive path is set to be substantially the same by changing the width of the conductive path, separately from this, in the conductive paths other than the wiring portion A,
The inventors have found that a printed circuit board that can be used for different purposes can be obtained by providing the wiring portion B in which the conductive path is set to a predetermined width in the same printed circuit board, and arrived at the present invention.

Next, the present invention will be described in detail.

In the present invention, the electric resistance value of the conductive path serving as the electric resistance value control section (wiring section A) is expressed by the following mathematical formula.

[0010]

[Equation 1]

R: Electric resistance value p: Conductor resistivity
l: circuit wiring length a: conductor width t: conductor thickness c: factor caused by processing

As is clear from the above equation, the electric resistance value R of the conductive path, excluding the factor c due to processing, is the resistivity p of the conductive path, the length l of the conductive path, and the thickness t of the conductive path. When is set to a design value, it becomes smaller as the width a of the conductive path becomes wider. Therefore, by controlling the width a of each conductive path in proportion to the length of each conductive path, the electrical resistance R of each conductive path can be set substantially the same. The main control of the width a is
Compared with the control of the length 1 and the thickness t, it has a wide application range and can obtain a resistance value generally lower than that of the latter, which is advantageous. In this way, the printed circuit board was formed with a plurality of conductive paths from one end to the other end. In some cases, the surface portion of the conductive path may be removed and the thickness t of the conductive path may be changed in order to adjust the electric resistance value during processing.

The conductive paths formed on the printed circuit board of the present invention are not limited to the U-shaped conductive paths described above, but may be conductive paths of various shapes. Also,
It is also possible to deal with the case where the electric resistance values of only some of the many conductive paths are set to be substantially the same.

When two or more kinds of printed circuit boards are used in combination, the electric resistance value of the conductive path of one circuit board and the electric resistance value of the conductive path of another circuit board are substantially equal to each other. It is possible to deal with the case of setting the same. In addition, by changing the width of the conductive path in the middle part of the conductive path, excluding the terminal part,
The case where the electric resistances of the respective conductive paths are made substantially the same can be dealt with. Further, it is preferable to use a copper foil for forming the conductive path, and more preferably, it is desirable to use a rolled copper foil as the copper foil. Most preferably, it is preferable to use annealed rolled copper foil or low temperature annealed rolled copper foil as the rolled copper foil in terms of the effect that the electrical resistivity is stable against thermal history.

Next, the present invention will be described based on embodiments.

[0016]

1 and 2 show an embodiment of the present invention. In the printed circuit board (flexible printed circuit board) of this embodiment, 50 conductive paths are formed in a U shape by annealed copper foil between a and b in the figure (for simplification, in the figure). 7), and the conductive path is a wiring portion A (shown by a solid line) that is a control portion of the electric resistance value.
And a wiring portion B (indicated by a broken line) which is a non-electrical resistance value control portion. In this printed circuit board, as is clear from FIGS. 1 and 2, the conductive path (circuit) of the U-shaped upper portion (a-side portion) is long and the conductive portion (b-side portion) of the lower portion is conductive. The road is getting shorter. And FIG.
As shown in FIG. 4, among the above-mentioned conductive paths, the conductive path of the upper portion (a side portion) in the U shape, that is, the X portion is a non-control portion of the electric resistance value. The Y portion is a control unit of the electric resistance value, and in the Y portion, the width of the conductive path closest to the a side portion is large, and the width of the conductive path in the b side portion is small. As a result, the electric resistance values of the conductive paths are substantially the same in all of the conductive paths of the Y portion of the printed circuit board (the A portion, the A portion, and the C portion). Here, “substantially the same” is included within the range of 10 to 20% in the vertical direction with reference to the middle of the maximum and minimum electric resistance values among the conductive paths of the Y portion. Say that.

In particular, in this printed circuit board, the width of the conductive path is changed by changing only the width of the conductive path portion of the part Y of the printed circuit board which is the control unit of the electric resistance value. The widths of the conductive paths of the parts A and C are not changed. That is, the part (a) is the connector insertion part, which cannot be changed because the width and thickness of the conductive path required for the connector insertion part are specified. Further, since the c portion is also a contact portion of a contact type having a small wiring area, it is difficult to control the width of the conductive path and the like, so control of the width of the conductive path in this portion is avoided. Since the a-part connecting the a part and the c-part has a relatively long conductive path and the width of the conductive path can be easily controlled, the width of the conductive path of this part and the a-part is controlled.

In order to control the width of such a conductive path, a raster scan method is used to draw a mask pattern of a photomask on a mask film to manufacture a photomask. In the present invention, the linear pattern in the mask pattern is used. Can be performed more accurately by drawing a portion corresponding to the Y portion (electrical resistance value control portion) of the portion A in FIG. 1 at an angle with respect to the scanning direction (horizontal direction). . That is, the drawing of the straight line pattern at an angle with respect to the scan direction can be performed by devising the input to the minicomputer provided in the raster scan system. In addition, even if a slight angle is used as the angle with respect to the scanning direction, it is sufficiently effective. That is, since the pixel size in the raster scan method is usually small, a slight angle is sufficiently effective, although it depends on the line length of the straight line pattern. By doing so, when drawing is performed based on the design value (width A of the conductive path and 3.2 pixels) shown in FIG. 3, a mask pattern (mixed pattern of 3 pixels and 4 pixels) as shown in FIG. Will be obtained. As can be seen from the comparison between FIG. 3 and FIG. 4, in the drawn pattern (FIG. 4), minute steps (grit) are formed on the upper and lower portions of the straight line portion. However, as a whole, the width A ′ of the pattern is almost the same as the width A of the design value. In this way, the width of each conductive path can be controlled to an arbitrary width. In this way, the width of each conductive path is changed to make the electric resistance value substantially constant. For controlling the electric resistance value among the 50 conductive paths (wiring patterns) in the printed circuit board of FIG. In the Y section, the longest conductive path on the a side (the conductive path closest to the X section) and the shortest b.
There was a 1.7-fold difference in the length of the conductive path from the side conductive path. Therefore, when the width of the conductive path on the a side was set to 0.52 mm and the width of the conductive path on the b side was set to 0.23 mm, the electric resistance values could be controlled to be substantially the same. That is, when the target set value is 0.80Ω, the electric resistance value of the entire conductive path is 0.
It was controlled to be within 841 ± 0.010Ω (mean ± standard deviation). That is, in the printed circuit board of FIG. 1, the fluctuation of the electric resistance value of each conductive path could be kept within about 1.2% (standard deviation).

5 and 6 show another embodiment of the printed circuit board according to the present invention. In this embodiment, the portion D, which is the non-control portion (wiring portion B) of the electric resistance value, has a U-shaped lower portion (d) from the portion C which is the control portion (wiring portion A) of the electric resistance value.
Substantially the same as that of FIG. 1 except that it is provided on the side part). In this embodiment, the target set value of each conductive path of the section C which is the control section (wiring section A) of the electric resistance value is 0.
At 80Ω, the electric resistance value of each conductive path is 0.775.
It was ± 0.011Ω (mean ± standard deviation), and almost the same result as the conductive path of the printed circuit board of the embodiment shown in FIG. 1 was obtained.

Further, another embodiment of the printed circuit board of the present invention is shown in FIG. In this embodiment, the printed circuit board is substantially U-shaped and is divided into five parts A to E, and the c portion is formed in a recess. This printed circuit board has two types of wiring parts, a wiring part A (shown by a solid line A) which is a control part of the electric resistance value and a wiring part B (shown by a broken line B) which is a non-control part of the electric resistance value. It is provided. Then, in the wiring portion A, the width of the conductive path in the upper portion of the U-shaped portion is set to be large and the width of the conductive path in the lower portion is set to be small in the portion D, similar to each of the printed circuit boards described above. As a result, the electric resistance value of each conductive path is
Substantially the same.

Although each printed circuit board is provided with only the cable portion on the circuit surface, as another embodiment, as shown in FIG. 8, electronic parts and IC mounting parts (mounting parts) are mounted. 2 shows a printed circuit board provided with lands 2). This printed circuit board has two types of wiring parts, a wiring part A (shown by a solid line A) which is a control part of the electric resistance value and a wiring part B (shown by a broken line B) which is a non-control part of the electric resistance value. It is provided. Then, in the wiring portion A, the portion on the right side of the mounting land 2 is in the conductive path control range, and the portion of the wiring portion A is combined so as to obtain a uniform electric resistance value by combining both the portion and the portion. Then, similarly to each of the printed circuit boards described above, the width of the conductive path in the upper portion of the U-shape is set to be large, and the width of the conductive path in the lower portion is set to be small. In the figure, for example, the power supply part is a part where power lines and signal lines coexist, and the electrical resistance value is individually specified for each conductive path a to e such as 0.5Ω or 0.2Ω.

Further, another embodiment is shown in FIG. This printed circuit board is substantially J-shaped, and like the above-mentioned printed circuit boards, the wiring section A (solid line A) is a control section for controlling the electric resistance value.
And a wiring portion B (indicated by a broken line B) which is a non-electrical resistance value control portion. Further, in the wiring portion A, the case portion, the corner portion, and the groove portion are non-control portions of the conductive path width, and the portions other than the groove portion to the groove portion, the straight line portion, and the like are the same as those of the printed circuit boards. By setting the width of the conductive path on the outer peripheral side to be large and the width of the conductive path on the inner peripheral side to be small, the width of the conductive path is appropriately changed to control the electric resistance value to be uniform.

Further, another embodiment is shown in FIG. This printed circuit board has a wiring part A which is a control part of an electric resistance value.
(Shown by a solid line) is a printed circuit board formed by one conductive path m, and this one conductive path m makes one round trip.
The broken line is a conductive path that serves as a non-control portion of the electric resistance value, and the mounting land 3 is provided at one end thereof. In such a shape, the width of the conductive path m is appropriately changed in all regions to control the electric resistance value to be uniform. By controlling the width of the conductive path m, a target electric resistance value can be set, and for example, this printed circuit board can be used as a heater.

In each of the above embodiments, when there are a plurality of conductive paths forming the wiring portion A which serves as a control section for the electric resistance value, the width of each conductive path is set to be different. From the longest conductive path of the book, set the width of the conductive path to a constant from the longest of the conductive paths and set the width of the conductive path to a constant value. The width of the conductive paths is set to a constant value, and the conductive paths below the conductive paths are set in groups of two or several to set the width of the conductive paths. By doing so, the overall electrical resistance value may be controlled to be substantially the same. That is, when there are a large number of conductive paths, such as 50 as described above, even if the width of each conductive path is changed little by little, due to variations in the manufacturing process, etc.
Sometimes it doesn't appear as expected. Therefore, it is rational to control the electric resistance value by forming a set of two or several pieces and changing the width of the conductive path for each set. Further, in the above-mentioned embodiment, the width dimension of the conductive path of only the straight line portion is changed, but the resistance values may be made substantially the same by changing the width dimension of the plurality of conductive paths. Further, although the embodiment is performed with the flexible printed circuit board, the present invention is not limited to the flexible printed circuit board and can be applied to the rigid circuit board.

The printed circuit board in which the electric resistance values of the conductive paths are controlled to be substantially the same as described above can be used, for example, for cable applications for transmitting electric signals. That is, when an electric signal of the same strength is applied to one terminal of a plurality of conductive paths, the signal transmitted to the opposite terminal becomes equal to the applied electric signal, and Variation in strength is reduced. The electric resistance non-control unit may be used as, for example, a ground line, a power line, a control signal line, or the like.

As another application of the printed circuit board of the present invention, when a constant voltage is applied between the left and right terminals,
There is an application to control the value of current flowing in a conductive path. It becomes possible to control the power consumption by controlling the current value. Depending on the circuit shape, it can also be used for controlling heat generation temperature, electromagnetic induction and the like.

[0027]

As described above, the printed circuit board of the present invention is a printed circuit board in which a plurality of conductive paths are extended from one end side to the other end side, and two kinds of wiring portions A and B are provided. Is equipped with. That is, by changing the width of at least a part of each conductive path, the wiring portion A in which the electric resistance value of each conductive path is set to be substantially the same as the conductive path other than the conductive path in which the width is changed. It is provided with a wiring portion B whose width is set to a predetermined width. Therefore, it can be applied to a new application in which the electric resistance values of the conductive paths between the left and right terminals need to be substantially the same. Moreover, the same printed circuit board can be used for different purposes. For example, while being used as a cable for transmitting an electric signal, the non-controlled portion of the electric resistance value can be used as, for example, a ground line, a power line, a control signal line, or the like.

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment of the present invention.

FIG. 2 is a partially enlarged plan view of a circled portion Z in FIG.

FIG. 3 is an explanatory view of forming the conductive paths of FIG.

FIG. 4 is an explanatory view of forming the conductive path of FIG.

FIG. 5 is a plan view of another embodiment of the present invention.

6 is a partially enlarged plan view of a portion W surrounded by a circle in FIG.

FIG. 7 is a plan view of still another embodiment of the present invention.

FIG. 8 is a plan view of another embodiment of the present invention.

FIG. 9 is a plan view of another embodiment of the present invention.

FIG. 10 is a plan view of another embodiment of the present invention.

FIG. 11 is a plan view of a conventional printed circuit board.

12 is a partially enlarged plan view of a circled portion A in FIG.

FIG. 13 is a plan view of another conventional printed circuit board.

FIG. 14 is a plan view of another conventional printed circuit board.

FIG. 15 is a plan view of another conventional printed circuit board.

FIG. 16 is a plan view of another conventional printed circuit board.

[Explanation of symbols]

 X Electric resistance non-control unit Y Electric resistance control unit

Claims (1)

[Claims] 1. A printed circuit board having a plurality of conductive paths extending from one end side to the other end side of a circuit surface, and provided with a wiring portion A and a wiring portion B shown below. Printed circuit board characterized by. (Wiring part A) In a plurality of conductive paths, the width of at least a part of each conductive path is changed to set the electric resistance value of each conductive path whose width is changed to be substantially the same. (Wiring part B) Of the plurality of conductive paths, other than the above-mentioned wiring part A, a wiring part in which the conductive path is set to a predetermined width.