JP2006173181A - Printed-wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To offer a printed-wiring board which can recognize visually vividly the image information on the electronic components mounted in the front and rear from the surface side in the double-sided mounting printed-wiring board. <P>SOLUTION: The printed-wiring board comprises a rear side image information pattern (a first insulating pattern layer 3) created by printing the pattern expressing the outline of the electronic components mounted on the surface side of an insulating board 1 on the rear side of the insulating board 1, wherein the conductive pattern is formed containing a mounting pad 2 for mounting two or more electronic-components in both sides; and a surface side image information pattern (a second insulating pattern layer 5) created by forming a solder resist layer 4 so as to cover the first insulating pattern layer 3, and by printing the pattern expressing the outline of the electronic components mounted on the front side on the upper part of the solder resist layer 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a multilayer printed wiring board such as a double-sided mounting board, and more particularly to a printed wiring board that displays the outer shape and specifications of mounting components mounted on the front and back sides on a board.

In recent high-density mounting printed wiring boards, various electronic components are mounted on the front and back with high density. These electronic components mounted on the front and back are electrically connected to each other on the insulating substrate by a conductor pattern and a through hole. In that case, in the test adjustment and failure analysis of the printed wiring board on which the electronic components are mounted, it is necessary to recognize the existence of electronic components that are electrically connected. Conventionally, it has been recognized by reversing the printed wiring board. By the way, in Japanese Patent Laid-Open No. 7-307535, in order to prevent mounting errors of electronic components, image information relating to mounting of front and back components is placed on the same surface of one side, and image information on the front and back sides is expressed differently (surface image information Information using solid lines and backside image information using broken lines) is disclosed.

That is, in FIG. 1 of Japanese Patent Laid-Open No. 7-307535, M1 to M3 are marks as image information of a surface-mounted electronic component, and M4 to M5 are marks as image information of a back-mounted electronic component. On the front surface S1, the mounting areas R1 to R3 for the surface-mounted electronic components are indicated by solid lines and the mounting areas r4 to r5 for the back-mounted electronic parts are indicated by broken lines.

Japanese Patent Laid-Open No. 7-307535

However, in Japanese Patent Application Laid-Open No. 7-307535, the image information of the electronic component mounted on the front surface S1 and the image information of the electronic component mounted on the back surface S2 are expressed on the same surface by two types of image information expression patterns. Therefore, when the back-mounted component is very small, image information on the front surface is represented by a broken line, and there is a problem that it is mistaken for a solid line expression due to bleeding at the time of screen printing.

In addition, there are many mounting pads and through-holes that electrically connect the front and back around the electronic component, and if the image information of the electronic component is expressed avoiding it, it will inevitably be drawn with a broken line, and a solid line and a broken line Therefore, it may be difficult to identify the front and back.

This invention has been made to solve the above problems, and image information such as electronic components mounted on the back side is printed with an insulating material on the front side before printing a solder resist applied on the front side. Then, the image information of the electronic components mounted on the front side is printed with an insulating material on the upper part after the solder resist printing, so that the electronic components (front and back mounting electronic components) can be reliably mounted with one type of image information expression pattern ( An object of the present invention is to provide a printed wiring board that can be identified (viewed) from the surface side of a component.

According to a first aspect of the present invention, there is provided a printed wiring board comprising: an insulating substrate having a conductive pattern including a plurality of electronic component mounting pad portions on both sides; and a substantially outer shape of the electronic component mounted on one surface of the insulating substrate. A first insulating pattern layer in which a pattern to be expressed is selectively printed on the other surface of the insulating substrate; and a solder that covers the first insulating pattern layer and covers the electronic component mounting pad portion except for the pad portion A resist layer and a second insulating pattern layer formed by selectively printing a pattern representing a substantially outer shape of an electronic component mounted on the solder resist layer on the solder resist layer are provided.

In the printed wiring board according to a second aspect of the present invention, the first insulating pattern layer and the second insulating pattern layer are expressed by a common line type. As described.

The printed wiring board according to a third aspect of the present invention is the printed wiring board according to the first or second aspect, wherein the first insulating pattern layer contains a fluorescent material.

The printed wiring board according to a fourth aspect of the present invention is the printed wiring board according to the third aspect, wherein the first insulating pattern layer emits red fluorescence when irradiated with ultraviolet rays.

According to this invention, the image information of the electronic component mounted on the back surface side is expressed on the front surface side facing through the insulating substrate, and the color of the solder resist layer printed on the front surface side (generally green) is transparent. Therefore, even if it is the same line type and the same color as the image information representing the electronic component mounted on the surface side, it can be easily identified by the color density and contrast, and the visibility is improved. .

In addition, since the image information of the electronic component mounted on the back side is printed below the solder resist layer, there is an effect of preventing falsification of the image information.

In addition, since the image information formed by the first insulating pattern layer containing the fluorescent material can be emitted with an arbitrary fluorescent color by ultraviolet irradiation, the visual effect is further improved.

Also, there is no need for two or more types of image information for front and back identification for one electronic component, and image information and tools used on each mounting surface (CAD electronic data, screen printing) Plate, film when using a photographic method, electronic data when using an ink-jet printing method, etc.), and there is an advantage that information management becomes easy.

Example 1.
Embodiment 1 of the present invention will be described below. FIG. 1 is a plan view seen from the surface of a printed wiring board according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes an insulating substrate, 2 denotes an electronic component mounting pad portion (mounting pad) for mounting an electronic component (not shown) mounted on the front surface side of the insulating substrate 1, and 3 denotes a back surface side of the insulating substrate 1. A first insulating pattern layer (also referred to as an image information pattern on the back side) printed on the front side of an image information pattern expressing the outer contour of the electronic component to be mounted, 3a is an electronic component (see FIG. (Not shown) is a notation (symbol) formed by the first insulating pattern layer 3 and a component position display pattern, both of which are image information patterns.

4 is a solder resist layer that protects the contact between the mounting component mounted on the insulating substrate 1 and the wiring pattern on the substrate and the wiring pattern from corrosion, and covers an unnecessary area when soldering the mounting component. A second insulating pattern layer (also referred to as a surface image information pattern) in which an image information pattern representing the outer contour of an electronic component mounted on the surface side is printed on the solder resist layer 4, 5 a is on the surface side of the insulating substrate 1. This is a symbol or component position display pattern formed by the second insulating pattern layer 5 such as the specification number of the electronic component to be mounted, both of which are image information patterns.

Next, a method for forming a printed wiring board will be described with reference to FIG. 1 denote the same or corresponding parts. FIG. 2 is a partial cross-sectional schematic view showing a layer structure mainly on the surface side of the printed wiring board. In the figure, copper foils previously formed on both surfaces of an insulating substrate 1 such as a glass epoxy material or a phenol material are etched using a desired mask pattern to form a conductor pattern such as a mounting pad 2, a wiring pattern, or a through hole land. . Next, an insulating material whose main component is an epoxy material is a pattern (image information pattern) close to the outer shape of the electronic component at a predetermined position on the front side corresponding to the installation position of the electronic component such as LSI, resistor, connector, etc. mounted on the back surface The first insulating pattern layer 3 is formed by screen printing and drying. In addition to the image information pattern based on the outline of the outer shape, the pattern of the electronic component to be mounted, the position display mark, and the like are printed at the same time. In this embodiment, a white pattern having a line width of 0.3 mm and a film thickness of about 8 μm is formed. However, it may be formed by a different pattern color such as a broken line other than the solid line.

  The image information pattern 3 of the electronic component mounted on the back side is printed on the front side, but the area overlapping the position of the mounting pad 2 on the front side is printed in the gap between the mounting pads 2 on the front side or printing of that area. Delete the pattern. Therefore, the image information pattern 3 does not necessarily have to coincide with the outline of the electronic component to be mounted, and may be a rough outline display. In addition, in order to display a reference pin position of an LSI or the like, a drawing pattern other than the outline display may be provided. In FIG. 2, in addition to the outline outline display of the general-purpose IC, a lead line for identifying the reference pin position is provided. Also, resistors and the like are displayed in a straight line. In any case, the image information pattern 3 is printed in the vicinity of the surface side of the target electronic component so as not to overlap the mounting pad 2 on the surface side.

Next, screen printing is performed once or twice so as to cover the insulating substrate 1 with the green solder resist layer 4 on the surface side of the insulating substrate 1 except for the mounting pad 2 region on the surface side of the LSI and other electronic components. The thickness of one time is 12 μm, and when electrical insulation is required, printing is performed again to ensure a desired film thickness.

Next, image information is printed and formed with the same material as the image information pattern 3 on the back surface at a predetermined position on the front surface corresponding to the installation position of an electronic component such as an LSI, resistor, connector, etc. mounted on the front surface side, and the second insulation pattern Layer 5 is assumed. In addition to the image information pattern based on the outline, this pattern is also printed with specifications of electronic components to be mounted, position display marks, and the like.

The image information pattern 5 of the electronic component to be mounted on the front side is printed on the solder resist layer 4 on the front side, but the area overlapping the position of the mounting pad 2 on the front side is printed in the gap between the mounting pads 2 on the front side. Alternatively, the print pattern in that area is deleted as in the back side. Therefore, the image information pattern 5 does not necessarily need to match the outer shape of the electronic component to be mounted, and may be a rough outer shape display. In addition, in order to display a reference pin position of an LSI or the like, a drawing pattern other than the outline display may be provided. Note that a solder resist layer is also coated on the back side of the insulating substrate 1, but the description is omitted because it is not the gist of the invention. In this embodiment, the double-sided printed wiring board is mainly described, but it goes without saying that image information may be formed on the surface side of the multilayered insulating substrate.

As described above, since the back side image information pattern 3 is identified through the green solder resist layer 4 printed on the front side, the front side image information pattern 5 and the back side image information pattern 3 are the solder resist layer. Even if the line type and the print color are the same, the front and back image information can be identified, and the electronic component mounting positions on the front and back can be confirmed from the front side. Further, since the image information pattern 3 on the back surface is formed on the lower surface of the solder resist layer 4, it also serves to prevent tampering.

Example 2
In the first embodiment, a general insulating material such as a silk printing material is used for the printed wiring board. In the second embodiment, a case where a fluorescent material is mixed with the first insulating pattern layer 3 will be described. Screen printing is performed by mixing a commercially available fluorescent material by ultraviolet irradiation with an epoxy insulating material. As the phosphor material (fluorescent material), zinc sulfide (ZnS) or cadmium sulfide (CdS) can be used to deactivate various impurities to obtain a phosphor material that emits a necessary spectrum.

In this embodiment, a red light-emitting phosphor is used, and a complementary color with the green solder resist 4 is used to obtain a clear image information pattern 3 during external UV illumination. First, an equal amount of fluorescent pigment is mixed in an insulating material mainly composed of an epoxy material in the first insulating pattern layer 3, screen-printed on the patterned insulating substrate 1, dried at about 220 ° C., and image information A pattern is formed. Next, after the first insulating pattern layer 3 is formed, the insulating substrate 1 and the first insulating pattern layer 3 are covered with the green solder resist layer 4 as in the first embodiment, and then the second insulating pattern layer 5 is formed.

By configuring as described above, when the image information pattern 3 of the insulating substrate 1 is identified, the image information pattern 3 that is plain in the case of normal visual recognition is irradiated with ultraviolet rays from the outside, whereby red image information is obtained. Since it is converted into the pattern 3, the presence of the solder resist layer 4 establishes a complementary color relationship in this case, and it becomes possible to visually recognize it more clearly. Further, by uniformly mixing red fluorescent material, blue fluorescent material, and green fluorescent material in the first insulating pattern layer 3, ultraviolet light is converted into mixed white light including three types of spectra of red, green, and blue. Therefore, the white hue described in the first embodiment can also be realized.

Example 3
In Example 2, the phosphor material is contained only in the first insulating pattern layer 3, but the phosphor material is applied to the first insulating pattern layer 3 and the second insulating pattern layer 5, and the solder resist layer is applied. When the image information pattern is to be extracted only during test adjustment and inconvenience analysis / analysis, all of the first insulating pattern layer 3, the solder resist layer 4 and the second insulating pattern layer 5 are printed in green. The image information pattern may be displayed (expressed) in a light emission color different from green by irradiation with ultraviolet rays.

It is a top view of the printed wiring board shown in Example 1 of invention. It is a partial cross section schematic diagram of the printed wiring board shown in Example 1 of invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insulation board | substrate, 2 Pad part for electronic component mounting (mounting pad), 3 1st insulating pattern layer (back surface image information pattern), 3a Symbol of back surface electronic component (back surface image information pattern), 4 Solder resist layer, 5 Second insulating pattern layer (surface image information pattern), 5a Symbol of surface electronic component (surface image information pattern).

Claims (4)

An insulating substrate formed with a conductor pattern including a plurality of electronic component mounting pads on both surfaces, and a pattern representing a substantially outer shape of an electronic component mounted on one surface of the insulating substrate on the other surface of the insulating substrate A selectively printed first insulating pattern layer, a solder resist layer covering the first insulating pattern layer and excluding the electronic component mounting pad portion, and mounted on the solder resist layer A printed wiring board comprising: a second insulating pattern layer formed by selectively printing a pattern representing a substantially outer shape of an electronic component on the solder resist layer. The printed wiring board according to claim 1, wherein the first insulating pattern layer and the second insulating pattern layer are expressed by a common line type. The printed wiring board according to claim 1, wherein the first insulating pattern layer contains a fluorescent material. 4. The printed wiring board according to claim 3, wherein the first insulating pattern layer emits red fluorescence when irradiated with ultraviolet rays.

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