JP2008085070A - Printed wiring board and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed wiring board with further improved flexibility, and electronic equipment. <P>SOLUTION: The printed wiring board is formed by using a flexible thin base material. A base material part partially cut in a thickness direction is provided at a bent part of the printed wiring board so as to improve the flexibility. A plating part applied to the partially cut base material part is provided so as to have a function for retaining a bent shape. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electronic device with improved flexibility.

  Conventionally, there has been a case where it is necessary to bend a printed wiring board used for an electronic device or the like depending on the use state. However, even in a printed wiring board using a thin base material, when it is fixed in a simply bent shape, it has a spring property, so that a component connected to the printed wiring board, for example, a connector is subjected to a spring back force. There was a malfunction.

  On the other hand, there is an invention that provides a low-cost, high-quality, foldable circuit board having high reliability and durability, and a manufacturing method thereof. A plurality of insulators arranged at intervals such that a void portion is arranged in the bent portion of the substrate, and a conductor arranged across the plurality of insulators and held by the plurality of insulators, The circuit board can be bent so that the gap portion is a bent portion of the substrate (Patent Document 1).

However, in this example, there is a problem that there is nothing in the gap corresponding to the portion to be bent, or there is only an ink-like insulator or a flexible insulator, and it cannot be countered by the force of spring back. Moreover, although processing methods, such as laser processing and press processing, are used as a formation method of a space | gap part, there also exists a problem that they cannot be said to be an appropriate response method with respect to the malfunction mentioned above.
JP 2001-267695 A (page 14, FIG. 16)

  An object of this invention is to provide the printed wiring board and electronic device which improved more flexibility.

  In order to solve the above problems, a printed wiring board according to the present invention is a printed wiring board using a thin flexible substrate, and is a substrate that is partially cut in the thickness direction at a bent portion of the printed wiring board. The flexibility is improved by providing the material portion.

  ADVANTAGE OF THE INVENTION According to this invention, the printed wiring board and electronic device which improved more flexibility are obtained.

  Examples of the present invention will be described below.

A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a side sectional view showing a configuration of a printed wiring board in which a bent portion is formed in a part showing an embodiment of the present invention. The printed wiring board 1 includes a wiring layer 3 stretched on a thin base material 2 and an insulating cover 4 that sandwiches and protects the both. In addition, the bending part 5 has a structure with the shaved part 6 of the thin base material 2. The material of the base material 2 is, for example, FR-4 or a glass epoxy resin layer, and the latter can be made more flexible by reducing the content of, for example, glass fiber as a blending component.

  FIG. 2 is a side cross-sectional view showing the manufacturing process of the printed wiring board. FIG. 2A shows a state in which a thin substrate 2 with a copper foil 7 is prepared. (B) is the state which removed the copper foil of the bending part 5 with the etching with respect to the state of (a). This corresponds to the pre-processing of the next cutting process (c). (C) is the state which performed the base-material cutting process by chemical | medical solution processing (desmear) next. As a result, a shaved portion 6 was formed.

  FIG. 3 is a sectional side view showing the next manufacturing process of the printed wiring board. FIG. 3A shows a state in which circuit formation is performed on the copper foil 7 by etching with respect to the state of FIG. In the next (b), the insulating cover 8 is formed by a solder resist or coverlay attaching process. Here, the completed printed wiring board corresponding to FIG. 1 was obtained.

  As a feature of chemical processing compared to laser processing and press processing as a method of forming voids, laser processing is difficult to control depth unless a stopper such as a conductor is provided, and chemical processing is easier. Dedicated jigs that match the shape are required, but not for chemical treatment.

  Desmear treatment used in the production of printed wiring uses chemicals (permanganate, sulfuric acid, chromic acid, etc.) to control the depth by controlling the amount of resin removed by the time of immersion in the chemical. Do. The thin portion of the substrate is, for example, 65 μm thick, and the depth of the gap is assumed to be about half of that.

  The elastic modulus indicating the hardness is the same for both the thin part of the substrate and the thick part of the other substrate in the bent part, for example, about 25 GPa. What is necessary is just to control the depth appropriately.

  FIG. 4 is a side sectional view showing an example of a bent configuration of the printed wiring board according to the embodiment. One end of the printed wiring board 1 is connected to the connector 9 by being bent in two different directions such as a crest side and a trough side at two bent portions 5.

  As an action, since the bent portion 5 is thin, the spring property is low and the flexibility is improved, and the stress load on the connector 9 is small. In addition, by providing the mountain-side and valley-side bent portions 5, an expansion / contraction effect in the left-right direction in the figure occurs, and stress is absorbed throughout. Further, the end point of the printed wiring board 1 on the side opposite to the connector 9 also has an effect that tolerance to the housing tolerance is large and stress on the external I / O is small.

  FIG. 5 shows the configuration of an electronic device according to the above-described embodiment, in which a printed wiring board having flexibility is partially mounted. Here, an example is shown in which the printed wiring board manufactured according to the above embodiment is applied to a small electronic device such as a portable computer.

  In FIG. 5, a main body 51 of a portable computer 50 is provided with a display unit casing 52 so as to be rotatable via a hinge mechanism. The main body 51 is provided with operation units such as a pointing device and a keyboard 53. The display unit housing 52 is provided with a display device 54 such as an LCD.

  The main body 51 is provided with a printed circuit board (motherboard) 55 incorporating various control circuit elements (P) for controlling the pointing device, the operation unit such as the keyboard 53 and the display device 54. This printed circuit board 55 is realized by using a printed wiring board (1) which is manufactured according to the embodiment shown in FIGS. 2 and 3 and which is partially bent (partly formed with a bent region 30). Is done.

  The printed wiring board used for the printed circuit board 55 is mounted in the main body (housing) 51 with the bending region 30 bent in accordance with the mounting space of the substrate housing portion of the main body (housing) 51. The printed circuit board 55 having a bent portion at a part thereof is bent in advance according to the mounting space of the board housing portion before being mounted on the main body (housing) 51, and mounted on the main body (housing) 51. In this case, it can be applied both in the case of bending in the mounting process. Further, in a substrate structure in which the plate surface of the substrate is bent by, for example, a heating process, the stress due to the bending can be absorbed by a bent portion formed in part when the substrate is mounted.

  By using the printed circuit board 55 having a bent portion in the above-described part, it is possible to provide a more compact electronic device that effectively utilizes the board mounting space in the main body (housing) 51. In addition, it is possible to provide inexpensive equipment by using a printed wiring board having a higher yield than FPC (flexible printed wiring board).

A third embodiment of the present invention will be described with reference to FIGS. 2 and 4 to 5 and 8. Description of the parts common to the first embodiment is omitted.
FIG. 7 is a side sectional view showing the next manufacturing process of the printed wiring board. FIG. 7A shows a case where the shaved portion is filled with copper in the state shown in FIG. 2C. Copper plating is added to the process, and as a result, the plating 10 is formed. Next, (b) shows a state where a circuit is formed by etching the copper foil 7. In the next (c), the insulating cover 8 is formed by a solder resist or cover lay attaching process. Here, the completed printed wiring board corresponding to FIG. 6 was obtained.

  FIG. 8 is a diagram showing a mounting form of the present embodiment. It is bent at the place of the plating 10. Compared to the first embodiment, the bent form is maintained by the plating 10. Ideally, the substrate should be thicker and thinner so that the force to maintain the bending shape of copper> the force to return when bending a thin substrate.

A third embodiment of the present invention will be described with reference to FIGS. 2 and 4 to 5 and FIGS. Description of parts common to the first and second embodiments is omitted.
FIG. 9 shows an example in which a combination with a hard (thick) substrate is performed. The configuration of the thin portion of the central substrate in the figure is the same as that of the second embodiment. The bent part 5 having improved flexibility is provided in the thick part, thin part and thinner part of the substrate without changing the material of the base material. A mounting form in which the bent portion 5 is bent as shown in FIG.

  As mentioned above, by using this invention, the spring property of a bending part becomes low and a spring back can be suppressed. Further, the flexibility of the bent portion is improved, and stress can be prevented from being transmitted to surrounding components.

In the embodiment of the present invention, the function of retaining the shape is added by plating the shaved portion.
The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.
Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above-described embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements according to different embodiments may be appropriately combined.

The sectional side view which shows the structure of the printed wiring board which formed the bending part in the part which concerns on embodiment of this invention. Side sectional drawing which shows the manufacturing process of the printed wiring board which concerns on the said embodiment. Side sectional drawing which shows the manufacturing process of the printed wiring board which concerns on the said embodiment. The sectional side view which shows the bending structural example of the printed wiring board which concerns on the said embodiment. FIG. 14 is a side view illustrating a configuration of an electronic device according to the invention. The sectional side view which shows the structure of the printed wiring board which formed the bending part in the part which concerns on another embodiment of this invention. Side sectional drawing which shows the manufacturing process of the printed wiring board which concerns on the said embodiment. The sectional side view which shows the bending structural example of the printed wiring board which concerns on the said embodiment. The sectional side view which shows the structure of the printed wiring board which formed the bending part in the part which concerns on another embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Printed wiring board, 2 ... Thin base material, 3 ... Wiring layer, 4 ... Insulation cover, 5 ... Bending part, 6 ... Cutting part, 7 ... Copper foil, 8 ... Insulation cover, 9 ... Connector, 10 ... Plating, DESCRIPTION OF SYMBOLS 30 ... Bending area | region, 50 ... Portable computer, 51 ... Main body, 52 ... Display part housing | casing, 53 ... Keyboard, 54 ... Display device, 55 ... Printed circuit board (mother board)

Claims (4)

In a printed wiring board using a thin base material having flexibility,
A printed wiring board characterized in that flexibility is improved by providing a base material portion partially cut in the thickness direction at a bent portion of the printed wiring board. 2. The printed wiring board according to claim 1, wherein the printed wiring board has a function of maintaining a bent shape by including a plated portion applied to the partially cut base material portion.   The printed wiring board according to claim 1, wherein the partially cut base material portion is formed by chemical treatment. The body,
An electronic device comprising a printed wiring board housed in the main body,
The said printed wiring board is a printed wiring board of Claim 1 or Claim 2. The electronic device characterized by the above-mentioned.

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