JPH06302924A - Printed wiring board - Google Patents

Abstract

PURPOSE:To increase the optical reading precision of a recognition mark, precisely mount mounting components, and increase quality, by including a member having large contrast difference from the recognition mark, in an inner layer just under the recognition mark. CONSTITUTION:In a printed wiring board wherein a plurality of board members 3 are stacked to obtain a hierarchical structure and a recognition mark 1 for optically recognizing the position of a mounted electronic component is arranged, a member 5 having large contrast difference from the recognition mark 1 is included in an inner layer just under the recognition mark 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board which has a hierarchical structure in which a plurality of board materials are superposed on each other and which has an identification mark for optically recognizing the position of an electronic component mounted on the board material. Among them, in particular, by incorporating a member with a large difference in contrast with the recognition mark in the inner layer immediately below the recognition mark, the optical reading accuracy of the recognition mark is improved and the mounted components are mounted accurately, and the quality is improved. The present invention relates to an improved printed wiring board.

[0002]

2. Description of the Related Art The printed wiring board is provided with a recognition mark which is optically recognized at the position of the mounting pad so as to accurately mount a mounting component such as a surface mounting type QFP (quad flat package). A conventional printed wiring board provided with the above-mentioned recognition mark will be described with reference to FIGS. 4 (a), (b) and FIG. As shown in the plan view of FIG. 4 (a), the printed wiring board 17 has a substrate for accurately mounting the mounting component on the component mounting pad 21 in the substantially central portion of the substrate material (hereinafter referred to as the base material 19). The recognition marks 23 are also provided on the substantially central portion of the material 19, both left and right lower portions and near the center of the upper portion.

An enlarged view of the vicinity of the recognition mark 23 at the substantially central portion in the drawing provided on the printed wiring board 17 is shown in FIG.
Shown in (b). In the figure, a circular recognition mark 23 is provided in a rectangular base material 19, and component mounting pads 21 are mounted on the upper and left sides of the recognition mark 23 in the figure. Inner layer patterns 29a, 29b and 29c are provided on the right side and the left side in the figure.
Has been implemented. FIG. 5 shows an AA cross section of the enlarged view of FIG. 4 (b). The solder resist 27 and the recognition mark 23 are mounted on the surface mounting of the first layer of the base material 19, and the inner layer patterns 29a and 29c are disposed between the first layer and the second layer.
Is built in. Further, inner layer patterns 29d and the like are also incorporated in the second and third layers.

As for the surface color of the base material of the printed wiring board 17 having the above-mentioned structure, for example, in the case of a flex-rigid printed board, when a flexible printed wiring board is used for the inner layer, the material is a polyimide resin, so that the recognition mark 23 is provided. The portion of the base material 19 that is formed is also brown, while the recognition mark 23 is a similar color to the copper color composed of copper foil.
The difference in color contrast (brightness) between the recognition mark 23 and the base material 19 was small.

[0005]

[Problems to be Solved by the Invention] However, in the past,
Since the surface color of the recognition mark 23 and the surface color of the base material 19 are similar colors, the difference in contrast is small and it is difficult to optically read the recognition mark 23, and there is a problem that the mounted component cannot be mounted accurately. As a countermeasure, recognition mark 2
There is also a method of soldering on the surface of No. 3 where there is a large difference in the surface color of the substrate 19 and the contrast, but it is difficult to evenly attach the solder to the surface of the recognition mark 23, and
Optically recognized mark 2 on the surface of the solder with scratches etc.
When 3 is read, there is a problem that it is difficult to recognize the recognition mark 23.

The present invention has been made in view of the above conventional problems, and an object of the present invention is to recognize a recognition mark by incorporating a member having a large contrast with the recognition mark in an inner layer immediately below the recognition mark. An object of the present invention is to provide a printed wiring board of high quality by improving the optical reading accuracy of the mark and mounting the mounted component accurately.

[0007]

In order to achieve the above object, a first invention according to claim 1 has a layered structure in which a plurality of substrate materials are superposed, and an electronic device mounted on the substrate material. In a printed wiring board having a recognition mark for optically recognizing the position of a component, a gist is that a member having a large contrast with the recognition mark is built in an inner layer immediately below the recognition mark.

A second aspect of the present invention is summarized in that a member having a large contrast with the recognition mark is an inner layer pattern.

[0009]

With the above-mentioned structure, the first aspect of the present invention
The invention of claim 1 has a hierarchical structure in which a plurality of substrate materials are superposed on each other, and the recognition mark is provided on the inner layer directly below the recognition mark for optically recognizing the position of the electronic component mounted on the substrate material. Since a member having a large contrast difference is built in, the optical reading accuracy of the recognition mark can be improved and the mounted component can be mounted accurately.

According to a second aspect of the present invention, since the member having a large contrast with the recognition mark is an inner layer pattern, the recognition mark is optically read without complicating the structure of the printed wiring board. The accuracy can be improved.

[0011]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a principal part view showing an embodiment of a printed wiring board of the present invention.

The printed wiring board is provided with a plurality of optical recognition marks at the positions of the mounting pads for optically recognizing mounting components such as a surface mounting type QFP (quad flat package). Of the plurality of recognition marks, the recognition mark 1 in the lower right part of the figure is provided in the substantially central portion of a rectangular substrate material (hereinafter referred to as a base material) 3. Although the recognition mark 1 has a circular shape, the shape is not limited to the circular shape, and may be a square shape as long as it can be recognized by a recognition mark reading device (not shown). A rectangular inner layer pattern 5 indicated by a broken line in the drawing has a rectangular inner layer pattern 5 around the rectangular base material 3 provided with the recognition mark 1 at a substantially central portion thereof and a first inner layer 2 and an inner layer 2 which will be described later.
It is built in between the second layer. Circular recognition mark 1 above
On the upper and left sides in the figure, component mounting pads 7 indicating the positions where the mounting components are mounted are mounted on the base material 3.

On the right side of the recognition mark 1 in the figure, the inner layer pattern 5 is provided between the first and second inner layers, which will be described later and are indicated by broken lines in the figure for electrically conducting the mounted components. Besides, the inner layer pattern 9a is incorporated. Further, on the left side of the recognition mark 1 in the drawing, the inner layer pattern 9b is mounted on the surface mounting of the first layer described later, and the inner layer pattern 9c is shown between the first layer and the second layer of the inner layer described later indicated by the broken line in the figure. Is built in. The inner layer patterns 9a and 9c have circular through holes 11 for connecting front and back surfaces of the base material 3 or interlayers described later.
Are formed. In the surface mounting of the printed wiring board, a solder resist 13 shown by hatching in the drawing is attached to the portion other than the base material 3 and the component mounting pad 7.

A description will be given with reference to the sectional view of FIG. 2 showing the hierarchical structure of the printed wiring board obtained by cutting the circular recognition mark 1 and the central portion of the substrate 3 of FIG. 1 in the AA direction.

Three layers of base material are superposed on the inner layer of the printed wiring board, and a recognition mark 1 is provided on the left side of the substantial center of the surface mounting of the first layer base material 3 in the figure. 1
In the figure, solder resists 13 are mounted on both left and right ends. The inner layer pattern 5 built in between the first layer and the second layer immediately below the recognition mark 1 in the vertical direction in the figure is the recognition mark 1 and the base material provided on the surface of the first inner layer. The width is wider than 3, and is larger than the solder resist 13 at the left and right ends of the recognition mark 1 in the figure, that is, larger than the punching dimension of the solder resist 13. The inner layer pattern 5 is the solder resist 13
Is formed larger than the punching dimension of the recognition mark 1 by reading the recognition mark 1 read by a recognition mark reading device (not shown) by covering the periphery of the recognition mark 1 with black which is the surface color of the inner layer pattern 5 described later. This is for facilitating optical recognition. The inner layer pattern 5 is the inner layer 1
It is built in between the second layer and the second layer.
It is sufficient that the recognition mark 1 can be optically recognized not only between the second layer and the second layer but also directly below the recognition mark 1 in the vertical direction in the figure, for example, between the second layer and the third layer.

Further, the inner layer pattern 5 is subjected to a blackening treatment (black oxide treatment) which is a pretreatment in the step of the inner layer pattern 5 like other inner layer patterns 5 to form irregularities on the surface of the inner layer pattern 5. This improves the adhesive strength between the base materials. Furthermore, since the surface color of the inner layer pattern 5 is black, the difference in contrast (brightness) with the brown recognition mark 1 made of copper foil is large. The shape of the recognition mark 1 is a square, but the shape is not limited to the square and may be a shape such as a circle. Inner layer patterns 9a and 9b are built in at the left and right ends of the inner layer pattern 5 in the figure.

Further, an inner layer pattern 9d and the like are built in between the second and third inner layers which are the hierarchical structure of the printed wiring board, and the inner layer pattern and the solder resist are mounted on the surface of the third layer. 13 etc. are mounted.

FIG. 3 shows a plan view of a printed wiring board on which the recognition mark 1 and the inner layer pattern 5 described in FIGS. 1 and 2 are mounted. Printed wiring board 1
The reference numeral 5 is provided with a recognition mark 1 for accurately mounting a component mounting pad 7 that indicates a mounting position of a mounting component at substantially the central portion of the base material 3, the left and right ends of the lower portion in the drawing, and the center of the upper portion. . The recognition marks 1 are provided at several positions on the base material 3 to improve the accuracy of optical recognition of the position of the component mounting pad 7. In addition, reference holes 17 are formed at the left and right ends of the lower part of the printed wiring board 15 in the figure.

With the above structure, the surface color of the base material 3 of the printed wiring board 15 is mainly brown, but the inner layer pattern 5 having a black surface is formed in the lower layer around the base material 3 on which the recognition mark 1 is mounted. , The difference in contrast (brightness) between the recognition mark 1 and the inner layer pattern 5 becomes large. Therefore, the accuracy of the optical reading of the recognition mark 1 by the recognition mark reading device (not shown) is improved, which speeds up the mounting process of the mounted component, and
It is possible to prevent the erroneous reading of the recognition mark 1 and, for example, prevent defective soldering and improve the quality of the printed wiring board.

Further, since a member having a large contrast between the recognition mark 1 and the second layer immediately below the recognition mark 1 in the vertical direction in the drawing is an inner layer pattern, the structure of the printed wiring board is complicated. It is possible to improve the optical reading accuracy of the recognition mark without

In this embodiment, the difference in contrast (brightness / darkness) between the recognition mark 1 and the inner layer pattern 5 is increased by using the inner layer pattern 5. However, the contrast (brightness / darkness) is not limited to the recognition mark 1 not limited to the inner layer pattern 5. Any member can be used as long as it has a large difference.

Further, since this embodiment can be realized only by incorporating the inner layer pattern 5, no special treatment is applied to the printed wiring board material, surface treatment, etc., thereby increasing the maintenance cost. Nor.

Furthermore, although the present embodiment has been described with respect to the printed wiring board 15 having a three-layer structure among the hierarchical structures, a hierarchical structure, for example, an eight-layer structure is also applicable.

[0025]

As described above, according to the first invention, the recognition mark and the contrast are provided in the inner layer directly below the recognition mark for optically recognizing the position of the electronic component mounted on the substrate material. Since a member having a large difference is built in, it is possible to improve the optical reading accuracy of the recognition mark, accurately mount the mounted component, and improve the quality. Further, according to the second aspect of the invention, since the member having a large difference in contrast with the recognition mark is the inner layer pattern, the optical reading accuracy of the recognition mark can be improved without complicating the structure of the printed wiring board.

[Brief description of drawings]

FIG. 1 is a main part diagram showing an embodiment of a printed wiring board of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a plan view of the printed wiring board of the present invention.

FIG. 4 is a plan view showing a conventional example.

FIG. 5 is a cross-sectional view showing a conventional example.

[Explanation of symbols]

 1 Recognition mark 3 Base material 5, 9a, 9b, 9c, 9d Inner layer pattern 7 Component mounting pad

Claims (2)

[Claims] 1. A printed wiring board, which has a hierarchical structure in which a plurality of board materials are superposed on each other, and which has a recognition mark for optically recognizing a position of an electronic component mounted on the board material. A printed wiring board, characterized in that a member having a large difference in contrast with the recognition mark is built in the inner layer provided directly below. 2. The printed wiring board according to claim 1, wherein a member having a large contrast with the recognition mark has an inner layer pattern.