JPH06326425A - Protective structure of flexible printed board - Google Patents

Abstract

PURPOSE:To prevent the title flexible printed board from damage caused by the deterioration with time and the like by percussion friction and expansion- contraction movement when the substrate is used, and also to prevent breakage of inner conducter by a method wherein only a small area of both end parts of a protective filter is fixed by adhesion to the surface of a flexible printed board and the intermediate part of the protective film is brought into a non- adhesive state. CONSTITUTION:The title flexible printed board 15 has a sheet of copper foil sandwiched between a base film and an overlay film, one end part of which is connected to the side of a telephone set main body through a connector 11, and the other end part is connected to the side of a movable part 4. Also, the intermediate part of the flexible printed board 15 is covered by a protective film 20. The protective film 20 is adhered and fixed to the surface of the board 15 by fixing parts 21a and 21b of small area located on both end parts, and on the other hand, the intermediate part, excluding both ends of the fixing parts 21a and 21b, is brought into the state wherein it is provided on the surface of the board 15 in a non-adhered state. Accordingly, the intermediate part exposed to outside can be moved freely from the flexible printed substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved protective structure for a flexible printed circuit board, and more particularly, it can be stored in a pocket, a bag or the like in a compact state with a cover closed when not in use such as a mobile phone and an electronic notebook. At the same time, the present invention relates to an improvement of a protective structure for a flexible printed circuit board used in a device having a structure in which a cover can be opened during use.

[0002]

2. Description of the Related Art As a portable telephone which is small and lightweight and suitable for carrying, there is, for example, one shown in FIGS. 2 (a) and 2 (b).
The telephone main body 1 includes a movable portion (sending portion) 4 which is pivotally supported by a rotating mechanism 2 located at a lower end portion thereof so as to be openable and closable, and includes a microphone 3 and the like. The telephone 1 is provided with a speaker 5, an operation unit 6 having a plurality of key switches, a display unit 7, an antenna 8, a battery 9, and the like. When making a call, the movable part 4 is opened about 180 degrees around the rotating mechanism 2 as shown in FIG. 1 (a), and when not in use, the movable part 4 is folded to the telephone body 1 side as shown in (b). It is closed to make it compact.

3 (a) and 3 (b) show a telephone body 1 and a movable portion (cover) in the conventional folding type portable telephone.
4 is a cross-sectional view showing a connection example of a flexible connector (flexible printed circuit board) for connecting the respective circuits of FIG. 4, wherein the flexible printed circuit board 10 has a copper foil laminated on a plastic film In many cases, a wiring pattern is formed by etching, or a wiring pattern is formed by printing a conductive pattern formed by mixing carbon or silver particles with an adhesive on a plastic film in a desired pattern.

By the way, one end of the flexible printed circuit board 10 is connected to a printed circuit board on the main body 1 side by a connector 1 or the like.
1 and the other end is connected to the circuit on the movable section 4 side, the movable section 4 is open when the movable section 4 is in the open state.
As shown in (b), a part of the rotating mechanism 2 is exposed. Exposing a part of the flexible printed circuit board to the outside when using a mobile phone causes not only design problems but also only the exposed part is scratched by a hard object or damaged by mechanical external force. Since there will be many opportunities to be hit, there is also a high risk that the internal conductor will break.

In order to solve such a problem, recently, as shown in FIG. 4, a protective film for reinforcement is attached to a flexible printed board portion exposed when the telephone is used. That is, a flexible printed circuit board 15 having a conventional structure in which a copper foil 13 is sandwiched between a base film 12 and an overlay film 14.
The protective film 16 is adhered on the upper surface with an adhesive or the like to prevent damage to the exposed portion and disconnection of the internal conductor.
In some cases, consideration is given not to impair the design by matching the color of the case. Also, instead of the protective film, a resin film for protection is used as the overlay film 1
Printing on 4 is also done.

However, in the protective structure shown in FIG. 4, the protective film 16 is formed on the overlay film 14.
However, the durability of the overlay film 14 due to bending and stretching is rather reduced as compared with the case of the flexible printed circuit board 15 alone. That is, when the number of times the flexible printed circuit board is bent and stretched when opening and closing the movable part is increased, stress is applied to the overlay film 14 when the protective film 16 bends, and the adhesive surface between the protective film 16 and the overlay film 14 (especially the overlay film 14) is increased. Wrinkles and distortions occur on the film side), and the wrinkles and the like often cause disconnection of the internal conductor. Further, when protective printing is performed on the overlay film 14, the printed resin film may be cracked or partially dropped, which may lead to disconnection.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and in a portable telephone in which a movable portion including a microphone and the like is openably and closably connected to a telephone body including a speaker and the like, the movable portion is movable with the telephone body. Prevents the flexible printed circuit board that connects to the parts from deteriorating over time due to bending and stretching when the movable part opens and closes, and prevents the exposed parts during use from being damaged by external impact, friction, etc. An object of the present invention is to provide a protective structure for a flexible printed circuit board that can be manufactured.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is a protective structure for a flexible printed circuit board which connects a device body and a cover which are supported by a rotating mechanism so as to be openable and closable with each other, and the cover is opened. When a protective film is additionally provided on the surface of the flexible printed circuit board that is exposed at the time, the protective film is adhesively fixed to the surface of the flexible printed circuit board only at its both ends, and the other intermediate portion is It is characterized in that it is in a non-adhesive state with respect to the surface of the flexible printed circuit board.

[0009]

The present invention will be described in detail below with reference to the embodiments shown in the accompanying drawings. FIG. 1 is a cross-sectional view showing a main structure of a protection structure according to an embodiment of the present invention. Reference will be made to FIG. 2, FIG. 3, and FIG.

The flexible printed board 15 has a structure in which a copper foil is sandwiched between the base film and the overlay film shown in FIG. 4, one end of which is connected to the telephone body 1 side through the connector 11, and the other. The end portion is connected to the movable portion 4 side. Since the intermediate portion of the flexible printed circuit board 15 is located on the rotating mechanism 2 as shown in the drawing, a part of the flexible printed circuit board 15 is exposed when the movable part (cover) 4 is opened as shown in the drawing. The protective film 20 covers the exposed substrate surface. This protective film 20 is different from the conventional protective film covering method shown in FIG. 4 in that both end portions 20 of the protective film 20 are covered.
a and 20b have fixed areas 21a and 21 having small areas, respectively.
In b, while the adhesive is fixed to the surface of the substrate 15, the intermediate portion (the portion affected by bending and stretching at the time of opening and closing) except the fixing portions 21a and 21b at both ends is not attached and is attached to the surface of the substrate 15. The structure is characteristic. The fixed portions 21a and 21b are configured so as to be located inside the case that constitutes the telephone body 1 and inside the case that constitutes the movable portion 4, respectively, and the intermediate portion exposed to the outside moves freely from the flexible printed circuit board 15. It is configured to be able to. Further, in a state where the flexible printed circuit board 15 and the protective film 20 are stretched to some extent as shown in FIG. 1 (a), dimensions are set in advance so that the protective film 20 side is slightly loose and faces the facing surface of the substrate 15. It is preferable to do this. The degree of this loosening is set within an effective range as a margin to the extent that the protective film 20 does not exert a strong stress on the substrate surface when both are bent or curved.

For this reason, only the protective film 20 is movable part 4.
The flexible printed circuit board 15 can be freely deformed (especially, relative movement by sliding) without being affected by the bending and stretching motions of the flexible printed circuit board 15 when it is opened and closed. There is no room for generation of wrinkles and disconnection of the conductor on the substrate side due to the occurrence of wrinkles, and the durability against bending and stretching of the substrate 15 accompanying the opening / closing operation of the movable portion can be significantly increased. In addition, the protective film has an advantage that the design can be improved. Further, it is an advantage that the existing design can be improved at a low cost without making a great change. The protective structure of the present invention is applicable not only to mobile phones but also to electronic notebooks and other electronic devices in general that are compact when not in use by connecting two components to each other via a rotating mechanism so as to be openable and closable. Applicable.

[0012]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, in a portable telephone in which a movable portion is openably and closably connected to a telephone body, or in an electronic notebook having a structure for opening and closing a cover, the rotary mechanism portion is exposed. In order to prevent damage to the flexible printed circuit board due to external force, wire breakage, and deterioration of the protective film over time due to bending and stretching, only the both ends of the protective film are fixed to the flexible printed circuit board over a small area. Since the parts are not in contact with the substrate, the flexible printed circuit board is sufficiently protected from mechanical external force, and the aesthetic appearance is not deteriorated.

[Brief description of drawings]

FIG. 1A and FIG. 1B are cross-sectional views showing a main configuration of an embodiment of the present invention.

2 (a) and 2 (b) are explanatory views of an external configuration of a conventional mobile phone.

3A and 3B are cross-sectional views showing a connection state of a flexible printed circuit board in a conventional mobile phone.

FIG. 4 is a cross-sectional view showing a conventional flexible printed circuit board protection structure.

[Explanation of symbols]

1 phone body, 2 rotation mechanism, 3 microphone,
4 movable part (sending part) 10 connector (flexible printed circuit board), 12 base film, 13 copper foil, 14 overlay film, 15 flexible printed circuit board, 20 protective film, 20a, 20b both ends, 21a, 21b fixed part,

Claims (1)

[Claims] 1. A protective structure for a flexible printed circuit board, which connects a device main body and a cover, which are openably and closably supported to each other through a rotating mechanism, to a surface of the flexible printed circuit board exposed when the cover is opened. A protective film is attached to the protective film, only the both ends of the protective film are adhesively fixed to the surface of the flexible printed circuit board, and the other intermediate portions are not adhered to the surface of the flexible printed circuit board. Protective structure for flexible printed circuit boards.