JP2007242906A - Printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed wiring board which makes it possible to print a symbol mark without producing such a projection part as to cause a trouble to a packaging of electronic components on a front surface of a solder resist film. <P>SOLUTION: In the printed wiring board; a conductive pattern having lands 3a, 3b to which the electronic components 6 are soldered and a solder resist film 4a are formed on a substrate 2, and a symbol mark 5a is printed in a region where the solder resist film 4a is formed. A hole 4a1 for accommodating the symbol mark 5a is formed at a part where the symbol mark 5a of the solder resist film 4a is printed. The symbol mark 5a is printed in the hole 4a1 and is provided so as not to project from a front surface of the solder resist film 4a. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a printed wiring board in which a conductive pattern having a land to which an electronic component is soldered and a solder resist film are formed on a substrate.

  In printed wiring boards, symbol marks are printed on predetermined portions in order to identify electronic components mounted on the wiring boards. In the conventional printed wiring board, as shown in Patent Document 1, this symbol mark is printed on the solder resist film.

  FIG. 6 schematically shows a state in which electronic components are mounted on a printed wiring board 1 'printed with a symbol mark according to the prior art, in which 2' is a substrate made of an insulating material, 3a 'and 3b'. Are the lands for soldering electronic components provided on the conductive pattern formed on the surface of the substrate 2 ', 3c' is the land provided on the conductive pattern formed on the back surface of the substrate 2 ', and 3d' is the land 3c '. Is another conductive pattern formed on the back surface of the substrate 2 '. 4a 'is a solder resist film formed in a region between the lands 3a' and 3b 'provided on the surface of the substrate 2', and 4b 'is positioned on the side of the land 3b' so that the surface of the substrate 2 ' The solder resist film 4c ′ formed on the substrate 2 is a solder resist film formed on the conductive pattern 3d ′ on the back surface side of the substrate. In the illustrated example, symbol marks 5a 'to 5c' are printed on the solder resist films 4a 'to 4c', respectively.

6 'has terminals 6a' and 6b 'at both ends, the terminals 6a' and 6b 'are soldered to the lands 3a' and 3b ', and 7a' and 7b 'are terminals of the electronic component 6', respectively. It is a solder fillet formed in the soldering part of 6a 'and 6b'. Reference numeral 8 'denotes a component (which may be an electronic component or an appropriate component other than an electronic component) disposed on the solder resist film 4b' and fixed to the substrate 2 '. is there.
JP-A-8-274416

  In the conventional printed wiring board in which the symbol mark is printed on the solder resist film, as shown in FIG. 6, since the convex portion is formed on the surface of the solder resist film by the symbol mark, the terminal 6a of the electronic component is formed. ', 6b' is placed on the lands 3a ', 3b', the electronic component 6 'is inclined with respect to the surfaces of the lands 3a', 3b 'by the convex portions, and the terminals 6a', 6b ' In some cases, the soldering surface of the lands 3a 'and 3b' cannot be kept parallel to each other. As shown, when the soldering surfaces of the terminals 6a 'and 6b' are inclined with respect to the soldering surfaces of the lands 3a 'and 3b', the terminals 6a 'and 6b' are soldered to the lands 3a 'and 3b'. The solder fillets 7a 'and 7b' formed at the time of application are non-uniform in shape, and there is a risk of poor soldering.

  Further, since the component 8 'disposed on the solder resist film 4b' is also inclined due to the convex portion formed by the symbol mark 5b ', when this component 8' is soldered to a land (not shown), it is the same as described above. Problem arises.

  Further, as described above, when the component 6 'or 8' is mounted in a state where it is inclined by the symbol mark, stress concentration occurs at the portion where the electronic component and the symbol mark are in contact with each other. There is a risk that the device may be damaged or the characteristics of the electronic component may be deteriorated, resulting in a decrease in reliability.

  Furthermore, in the conventional printed wiring board, since the symbol mark is printed on the solder resist film, the finished thickness d ′ of the printed wiring board is increased by the thickness of the symbol mark, which is the reason for this. There is a problem that it is one of the factors that hinder the downsizing of electronic devices that incorporate the.

  When the component is mounted in a state where it is inclined by the symbol mark, not only the thickness dimension D ′ of the unit composed of the printed wiring board and the component mounted on the printed wiring board is increased, Since the thickness dimension D ′ varies depending on the degree of inclination of the parts, when the unit is accommodated in the case, it is necessary to provide a margin for the dimension of the case. This is intended to reduce the size of the case. There was also a problem of becoming an obstacle.

  An object of the present invention is to provide a printed wiring board capable of printing a symbol mark on a surface of a solder resist film without causing a convex portion that hinders mounting of an electronic component. It is in.

  Another object of the present invention is to provide a printed wiring board in which a symbol mark can be provided without increasing the finished thickness.

  Still another object of the present invention is to enable the components to be always mounted in a fixed posture, and to prevent the overall thickness dimension of the mounted components from varying depending on the mounting posture of the electronic component. It is to provide a printed wiring board.

  The present invention relates to a printed wiring board in which a conductive pattern having a land to which an electronic component is soldered and a solder resist film are formed on a substrate, and a symbol mark is printed in a region where the solder resist film is formed. is there.

  In the present invention, a hole is formed in a portion of the solder resist film where the symbol mark is printed, and the symbol mark is printed in the hole.

  With this configuration, the symbol mark can be printed without forming convex portions on the substrate that cause the components to be mounted to be tilted. Therefore, the components must always be mounted without being tilted with respect to the surface of the substrate. Can do. Therefore, the shape of the solder fillet formed when the terminals of the electronic component are soldered to the lands can be made uniform so that the soldering can be performed well, and the reliability of the soldered portion of the electronic component is improved. Can do.

  In addition, when configured as described above, the component is tilted with respect to the board surface of the board, whether the component is mounted in contact with the solder resist film or when the component terminal is soldered to the land. Therefore, the components can always be mounted in the same posture, and the overall thickness dimension in a state where the components are mounted on the printed wiring board can be prevented from varying depending on the mounting posture of the components.

  Furthermore, if comprised as mentioned above, since a symbol mark does not protrude from the surface of a soldering resist film, the finishing thickness of a printed wiring board can be made thinner than before.

  In addition, when configured as described above, when the component is mounted in contact with the solder resist film, the component can always be in surface contact with the solder resist film, so that stress is applied to a specific part of the mounted component. Concentration can be prevented from damaging parts or changing their characteristics.

  In a preferred embodiment of the present invention, a hole is formed in a portion covering the conductive pattern of the solder resist film, and a symbol mark is printed in the hole.

  In another preferred embodiment of the present invention, a hole is formed in a portion of the solder resist film covering the substrate, and a symbol mark is printed in the hole.

  In the printed wiring board according to the present invention, when an electronic component is soldered to the land, there is a solder resist film in which a hole having a symbol mark printed therein is formed in a region below the electronic component. In this case, it is preferable to form the land to which the electronic component is soldered so as to have a thickness equal to or greater than the thickness of the solder resist film that will be present under the electronic component to be soldered to the land.

  In such a configuration, when the electronic component (surface mount component) is soldered and mounted on the land, the solder resist film and the symbol mark affect the contact state between the terminal of the electronic component and the land. Therefore, the entire soldered surface of the terminal of the electronic component can always be kept in stable surface contact with the surface of the land. Therefore, the shape of the solder fillet formed on the soldered portion of the electronic component can be made ideal, and the reliability of the soldered portion of the electronic component can be improved.

  In a preferred aspect of the present invention, the upper symbol mark is printed so as to fill at least a part of the hole formed in the solder resist film.

  The symbol mark is preferably provided so as not to protrude from the surface of the solder resist film.

  As described above, according to the present invention, a hole is formed in a portion of the solder resist film where the symbol mark is printed, and the symbol mark is printed in the hole, so that the component can be mounted on the surface of the solder resist film. It is possible to print the symbol mark without forming an influencing convex portion, and it is possible to prevent the mounted component from being inclined by the symbol mark. Therefore, when soldering the terminals of the electronic component to the land on the board, the soldering surface of each terminal is kept parallel to the soldering surface of the land, and the terminals of the electronic component are soldered to the land. The shape of the resulting solder fillet can be made uniform, and soldering can always be performed well.

  In addition, according to the present invention, when mounting the component in contact with the solder resist film, the component is not inclined by the symbol mark, so that the component is always mounted in surface contact with the solder resist film. can do. Therefore, the components can always be mounted in the same posture, and the overall thickness dimension in a state where the components are mounted on the printed wiring board can be prevented from varying depending on the mounting posture of the electronic component.

  Furthermore, according to the present invention, since the symbol mark can be prevented from protruding from the surface of the solder resist film, the finished thickness of the printed wiring board is made thinner than before and the printed wiring board is incorporated. It is possible to further reduce the size of the device.

  Further, according to the present invention, when the component is mounted in contact with the solder resist film, the electronic component can always be brought into surface contact with the solder resist film, so that stress is applied to a specific portion of the mounted component. Concentration can be prevented from damaging parts or changing their characteristics.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 schematically shows a state in which components are mounted on a printed wiring board 1 according to a preferred embodiment of the present invention. In the figure, reference numeral 2 denotes a substrate. In this example, the substrate 2 is made of an insulating material. Conductive patterns having lands 3a and 3b for soldering the terminals 6a and 6b of the surface mount electronic component 6 are formed on the surface of the substrate 2, and other electronic components are soldered on the back surface of the substrate 2. Conductive patterns having lands 3c for the purpose and other conductive patterns 3d are formed. A solder resist film 4a is formed so as to cover a region between the lands 3a and 3b on the surface of the substrate 2, and a solder resist film 4b is formed so as to cover the surface of the substrate 1 on the side of the land 3b.

  A solder resist film 4c is formed on the back surface of the substrate 2 so as to cover the conductive pattern 3d. The solder resist films 4a to 4c have a uniform thickness and are formed to have a flat surface. In addition, the electronic component is soldered so that the surface mount electronic component can be stably held on the substrate so that the height of the solder resist film does not become higher than the height of the land. The lands 3a to 3c are formed so as to have a film thickness equal to or larger than that of the solder resist film.

  In the illustrated example, the thickness of the lands 3a to 3c and the conductive film 3d and the thickness of the solder resist films 4a to 4c are set equal to each other. However, the present invention thus provides the lands 3a to 3c and the conductive film 3d. The present invention is not limited to the case where the thickness and the thickness of the solder resist films 4a to 4c are made equal.

  In the present invention, holes 4a1 to 4c1 for receiving the symbol marks are formed in the portions of the solder resist films 4a to 4c where the symbol marks are printed, and the symbol marks 5a to 5c are printed in these holes. . The holes 4a1 to 4c1 need only have a shape suitable for printing a symbol mark on the inside thereof, and may have an appropriate cross-sectional shape such as a round hole, a long hole, or a square hole. In the present embodiment, the holes 4a1 to 4c1 are almost completely filled with the paint forming the symbol marks 5a to 5c, respectively. The illustrated symbol marks 5a to 5c are provided so that their respective surfaces are located on substantially the same plane as the surfaces of the solder resist films 4a to 4c, and the symbol marks are printed on the solder resist film when the symbol marks are printed. Care is taken not to protrude from the surface.

  When manufacturing the printed wiring board, a conductive film is formed on both the front and back surfaces of the substrate 2 and then a coating film for forming a solder resist film is formed so as to cover the entire plate surface of the substrate. The solder resist film is formed by irradiating the paint for forming the solder resist film with ultraviolet rays while masking the exposed portion of the pattern, the exposed portion of the board surface of the substrate, and the portion where the holes 4a1 to 4c1 are to be formed. To do. Thereafter, the part of the paint for forming the solder resist film that has not been irradiated with ultraviolet rays is washed away with chemicals to expose the exposed part of the conductive pattern and the part of the substrate surface to be exposed as shown in FIG. And the holes 4a1 to 4c1 are formed. Next, symbol marks 5a to 5c are printed in the holes 4a1 to 4c1, thereby completing the printed wiring board 1 as shown in FIG.

  As shown in FIG. 4, the symbol marks 5a to 5c have their surfaces retracted closer to the substrate 2 than the surfaces of the solder resist films 4a to 4c (so as to fill at least part of the holes). As shown in FIG. 5, it may be printed with a part of the substrate surface in the holes 4a1 and 4b1 and a part of the conductive film in the hole 4c1 exposed.

  In the example shown in FIG. 1, terminals 6a and 6b at both ends of the electronic component 6 are placed on the lands 3a and 3b, and the terminals 6a and 6b are soldered to the lands 3a and 3b. Further, the component 8 is mounted on the solder resist film 4b. When the component 8 is an electronic component, its terminal portion is soldered to a land (not shown) formed on the surface of the substrate 2.

  As described above, when a hole for accommodating the symbol mark is formed in a portion where the symbol mark of the solder resist film is printed, and the symbol mark is printed in the hole, a component is formed on the surface of the solder resist film. Since the symbol mark can be printed without forming a convex portion that affects the mounting of the electronic component 6, when the electronic component 6 is arranged on the lands 3 a and 3 b and on the solder resist 4 b When appropriate components 8 are arranged, these components can be prevented from being inclined with respect to the plate surface of the substrate 2. Therefore, the soldering surface of the terminal of the electronic component and the soldering surface of the land can always be kept in parallel, and the electronic component terminal and the land are always in surface contact in the same state so that the electronic component is placed on the land. The shape of the solder fillet formed when soldering can be made uniform.

  Also, with the configuration described above, when mounting the component 8 in contact with the solder resist film 4b, the component is not inclined by the symbol mark, so that the component 8 is always in surface contact with the solder resist film. It can be implemented in the state. Therefore, the component 8 can always be mounted in the same posture, and the overall thickness dimension D in a state where the component is mounted on the printed wiring board can be prevented from varying depending on the mounting posture of the component.

  Further, since the symbol marks 5a to 5c can be prevented from projecting from the surfaces of the solder resist films 4a to 4c, the finished thickness d of the printed wiring board can be made thinner than before. Thus, it is possible to further reduce the size of the apparatus in which the printed wiring board is incorporated.

  Moreover, when comprised as mentioned above, when mounting the component 8 in a state in contact with the solder resist film, the electronic component can always be brought into surface contact with the solder resist film, so a specific part of the mounted electronic component. It is possible to prevent stress concentration from occurring on the electronic component and thereby damage the electronic component or change its characteristics.

  In the above description, as shown in FIG. 2, a solder resist film having a hole is formed and then a symbol mark is printed in the hole of the solder resist film. However, the symbol mark is printed first, then the symbol mark is printed. By forming the solder resist film while avoiding the portion where the mark is printed, it is possible to obtain a printed wiring board in which the symbol mark is printed in the hole formed in the solder resist film.

  In the above embodiment, the solder resist film is illustrated as having the same film thickness as that of the conductive pattern film. However, generally, the film thickness of the solder resist film is set to be smaller than the film thickness of the conductive pattern.

  In the present invention, it is only necessary to prevent the convex parts that incline the component to be mounted with respect to the board surface of the substrate from being formed on the surface of the solder resist film. The relationship between the film thickness and the thickness of the solder resist film is arbitrary. That is, in the present invention, it is sufficient that the soldering surface of each terminal of the electronic component having the terminal soldered to the land and the soldering surface of the land are always parallel to the plate surface of the substrate. When there is a component that is mounted in contact with the solder, the interface between the component and the solder resist only needs to be parallel to the board surface of the board, so the surface of the solder resist film can be made flat In this case, the thickness of the solder resist film may be slightly larger than the thickness of the conductive pattern. However, in order to reduce the finished thickness of the printed wiring board, it is desirable to make the film thickness of the solder resist film thinner than the film thickness of the conductive pattern.

    When the film thickness of the solder resist film 4a provided between the lands 3a and 3b to which the electronic components are soldered is smaller than the land 3a and 3b, it is printed in the hole 4a1 provided in the solder resist film 4a. The symbol mark 5a may slightly protrude from the surface of the solder resist film 4a as long as it does not protrude from the surfaces of the lands 3a and 3b. However, it is necessary to prevent the symbol mark 5b printed in the hole 4b1 provided in the solder resist film 4b on which components are placed from protruding from the surface of the solder resist film 4b. Therefore, in the present invention, it is preferable to always provide each symbol mark so as not to protrude from the surface of the solder resist film.

  In the above description, the substrate 2 is made of an insulating material. However, in order to improve heat dissipation from the electronic component, the present invention is also applied to the case where a metal substrate whose surface is covered with an insulating film is used. Can be applied.

It is sectional drawing which showed the state which mounted the electronic component on the printed wiring board concerning one Embodiment of this invention. It is sectional drawing which showed the state which formed the soldering resist film on the board | substrate in the process of manufacturing the printed wiring board shown in FIG. It is sectional drawing which showed an example in the state which printed the symbol mark in the hole of the soldering resist film | membrane shown in FIG. It is sectional drawing which showed the other example of the state which printed the symbol mark in the hole of the soldering resist film | membrane shown in FIG. FIG. 10 is a cross-sectional view showing still another example of a state in which a symbol mark is printed in the hole of the solder resist film shown in FIG. 2. It is sectional drawing which showed the state which mounted the electronic component on the conventional printed wiring board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printed wiring board 2 Board | substrate 3a thru | or 3c Land 3d Conductive pattern 4a thru | or 4c Solder resist film 5a thru | or 5c Symbol mark 6 Electronic component 8 Electronic component or other appropriate components

Claims (6)

In a printed wiring board in which a conductive pattern having a land to which an electronic component is soldered and a solder resist film are formed on a substrate, and a symbol mark is printed in a region where the solder resist film is formed,
A hole is formed in a portion of the solder resist film where the symbol mark is printed,
The symbol mark is printed in the hole;
Printed wiring board characterized by In a printed wiring board in which a conductive pattern having a land to which an electronic component is soldered and a solder resist film are formed on a substrate, and a symbol mark is printed in a region where the solder resist film is formed,
A hole is formed in a portion covering the conductive pattern of the solder resist film,
The symbol mark is printed in the hole;
Printed wiring board characterized by In a printed wiring board in which a conductive pattern having a land to which an electronic component is soldered and a solder resist film are formed on a substrate, and a symbol mark is printed in a region where the solder resist film is formed,
A hole is formed in a portion covering the substrate of the solder resist film,
The symbol mark is printed in the hole;
Printed wiring board characterized by In a region below the electronic component when the electronic component is soldered to the land, there is a solder resist film in which a hole in which the symbol mark is printed is formed,
4. The land to which the electronic component is soldered is formed so as to have a thickness equal to or greater than a thickness of a solder resist film that will exist under the electronic component to be soldered to the land. Printed wiring board.   The printed wiring board according to claim 1, wherein the symbol mark is printed so as to fill at least a part of the hole. The printed wiring board according to claim 1, wherein the symbol mark is provided so as not to protrude from a surface of the solder resist film.

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