JP2005285919A - Flexible wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flexible wiring board for which small height can be further promoted. <P>SOLUTION: A conductor pattern 3 is formed on the surface of an insulating substrate 2, and a hole 21 for housing a ball-like electrode 9 for a printed circuit board 6 is formed on the conductor pattern 3, in a manner of penetrating the insulating substrate 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a flexible wiring board, and more particularly to a flexible wiring board that can be directly electrically connected to a counterpart connection object without using a connector.

  Conventionally, a contact sheet for electrically connecting a substrate and an integrated circuit having a spherical terminal is known (see Patent Document 1 below).

  This contact sheet has a sheet and a contact spring. The sheet is made of an insulating elastic material. A large number of through holes corresponding to the spherical terminals are formed in the sheet. The contact spring is composed of a plurality of cantilevers. Each cantilever is formed of a conductive material. One end of each shaped beam is fixed to the sheet, and the other end protrudes into the through hole. Each cantilever has a lower substrate portion and a spherical terminal holding portion. The lower substrate portion is formed adjacent to the fixed portion of the cantilever, and the spherical terminal holding portion is formed at the other end of the cantilever and is bent toward the spherical terminal. One spherical terminal is held by the spherical terminal holding portion of one set of cantilevers.

In order to electrically connect the integrated circuit and the substrate using the contact sheet, the contact sheet is disposed between the integrated circuit and the substrate together with the spacer. At this time, the spherical terminal and the planar terminal of the substrate face each other through the through hole of the sheet and the hole of the spacer. Then, the contact sheet and the spacer are sandwiched between the integrated circuit and the substrate. As a result, the spherical terminal and the spherical terminal holding member of the cantilever are pressed against each other, and the spherical terminal holding portion is elastically deformed and pressed against the spherical terminal, and is pressed against the planar terminal of the substrate. In this way, the integrated circuit and the substrate are electrically connected.
JP 2001-167857 A (see paragraphs 0019-0020, FIG. 1)

  As described above, in the conventional method, since the contact sheet is interposed between the integrated circuit and the substrate, the entire assembly including the integrated circuit and the substrate is compared with the case where the integrated circuit and the substrate are directly connected. The thickness (dimension in the connecting direction) is increased, and there is a limit to so-called low profile (reducing the dimension in the connecting direction).

   This invention is made | formed in view of such a situation, The subject is providing the flexible wiring board which can accelerate | stimulate further height reduction.

  In order to solve the above-mentioned problem, the flexible wiring board of the invention of claim 1 is a flexible wiring board comprising a flexible insulating substrate and a conductor pattern formed on the surface of the insulating substrate. On the pattern, a hole for receiving the protruding electrode of the counterpart connection object is formed so as to penetrate the insulating substrate.

  As described above, since the hole for receiving the protruding electrode of the counterpart connection object is formed on the conductor pattern so as to penetrate the insulating substrate, the protruding electrode of the counterpart connection object is inserted into the hole. By utilizing the elasticity of the insulating substrate, the conductor pattern on the insulating substrate can be pressed against the protruding electrode of the counterpart connection object.

  According to a second aspect of the present invention, in the flexible wiring board according to the first aspect, a gel layer is formed on the back surface of the insulating substrate.

  Since the gel layer is formed on the back surface of the insulating substrate as described above, when the protruding electrode of the mating connection object is inserted into the hole of the insulating substrate, the elasticity of the gel layer is insulated together with the elasticity of the insulating substrate. It acts as a force for pressing the conductor pattern on the substrate against the protruding electrode of the counterpart connection object.

  According to a third aspect of the present invention, in the flexible wiring board according to the first aspect, a gel layer is formed inside the insulating substrate, and the holes penetrate the gel layer.

  As described above, the gel layer is formed inside the insulating substrate, and the holes penetrate the gel layer. Therefore, the gel layer is held on the insulating substrate regardless of the temperature change.

  According to a fourth aspect of the present invention, in the flexible wiring board according to the first, second, or third aspect, slits are formed radially from the hole.

  Since the slits are formed radially around the hole as described above, the hole is likely to expand when the protruding electrode is inserted into or removed from the hole.

  As described above, according to the first aspect of the present invention, the flexible wiring board can be directly electrically connected to the counterpart connection object without using a contact sheet or a connector, thereby further promoting a reduction in height. can do.

  According to the invention of claim 2, since the conductor pattern on the insulating substrate is reliably pressed by the protruding electrode of the counterpart connection object, the contact stability is improved.

  According to invention of Claim 3, it can prevent that a gel layer peels from an insulated substrate by a temperature change.

  According to the invention of claim 4, since the hole is easy to expand when the protruding electrode is inserted into or removed from the hole, the flexible wiring board and the mating connection object can be easily connected and disconnected. It can be carried out.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of a flexible wiring board according to the first embodiment of the present invention.

  As shown in FIG. 1, the flexible wiring board 1 includes an insulating substrate 2 and a conductor pattern 3.

  The insulating substrate 2 has flexibility. As a material of the insulating substrate 2, for example, a resin such as polyester or polyimide is suitable. A plurality of holes 21 are formed in the insulating substrate 2. The plurality of holes 21 are arranged at a predetermined pitch along a predetermined direction. The inner diameter of the hole 21 is smaller than the outer diameter of a ball electrode (projection electrode) 9 described later.

  The conductor pattern 3 is composed of a plurality of conductor lines 31 formed on the surface of the insulating substrate 2. The plurality of conductor lines 31 are arranged at a pitch equal to the arrangement pitch of the holes 21. Each conductor line 31 extends linearly from one end of the insulating substrate 2 to the other end. Each conductor line 31 has a land portion 31a. The land portion 31 a is formed around the hole 21.

  The back surface of the insulating substrate 2 is covered with the gel layer 4. For example, silicon gel is suitable as the material of the gel layer 4. A plurality of holes 41 (see FIG. 3) are formed in the gel layer 4. Each hole 41 faces the hole 21 of the insulating substrate 2. The inner diameter of the hole 41 is equal to the inner diameter of the hole 21. A through hole (hole) 11 is formed by the hole 21 and the hole 41.

  A plurality of slits 12 are formed around the through hole 11. The plurality of slits 12 extend radially around the through hole 11. The slit 12 reaches the gel layer 4 from the conductor line 31.

  FIG. 2 is a perspective view of a printed circuit board which is a counterpart connection object of the flexible wiring board shown in FIG.

  As shown in FIG. 2, the printed circuit board 6 includes an insulating substrate 7, a conductor pattern 8, and a plurality of ball-shaped electrodes 9.

  For example, an epoxy resin is suitable as the material of the insulating substrate 7.

  The conductor pattern 8 is composed of a plurality of conductor lines 81 formed on the surface of the insulating substrate 7. The plurality of conductor lines 81 are arranged at a pitch equal to the arrangement pitch of the conductor lines 31. Each conductor line 81 extends linearly from one end of the insulating substrate 7 to the other end.

  The ball-shaped electrode 9 has conductivity. As a material of the ball-shaped electrode 9, for example, solder is suitable. The plurality of ball-shaped electrodes 9 are fixed to one end of the conductor line 81 and are electrically connected to the conductor line 81.

  3 is a cross-sectional view showing a state before the flexible wiring board is connected to the printed circuit board, FIG. 4 is a cross-sectional view showing a state in which the through holes of the flexible wiring board are widened by the ball-shaped electrodes of the printed circuit board, and FIG. It is sectional drawing which shows the state in which the wiring board was connected to the printed circuit board.

  Next, a procedure for connecting the flexible wiring board 1 and the printed circuit board 6 will be described.

  First, one end portion of the flexible wiring board 1 is disposed above the ball-shaped electrode 9 of the printed circuit board 6, and the flexible wiring board 1 is lowered to put the upper portion of the ball-shaped electrode 9 into the through hole 11. Then, a jig 15 is placed on the flexible wiring board 1. The jig 15 has a plurality of holes 151. The hole 151 faces the through hole 11. The inner diameter of the hole 151 is larger than the outer diameter of the ball electrode 9.

  Next, as shown in FIG. 4, the jig 15 is pushed down. If it does so, the slit 12 will open and the internal diameter of the through-hole 11 will become large.

  When the jig 15 is further pushed down, the inner diameter of the through-hole 11 is further increased, so that the ball-shaped electrode 9 passes through the through-hole 11 and the flexible wiring board 1 is placed on the printed board 6 accordingly.

  At this time, as shown in FIG. 5, the peripheral portion of the through hole 11 bends toward the printed circuit board 6, sinks under the ball-shaped electrode 9, and the gel layer 4 is crushed. As a result, the conductor line 31 of the flexible wiring board 1 is pressed against the ball-shaped electrode 9 by the elasticity of the insulating substrate 2 and the gel layer 4, and the flexible wiring board 1 is electrically connected to the printed board 6.

  To release the flexible wiring board 1 from the printed circuit board 6, one end of the flexible wiring board 1 is lifted so as to be peeled off from the printed circuit board 6. Then, the peripheral portion of the through hole 11 is further bent toward the printed circuit board 6, the inner diameter of the through hole 11 is increased, and the ball-shaped electrode 9 comes out of the through hole 11. As a result, the flexible wiring board 1 is detached from the printed board 6.

  Next, the effect of this embodiment will be described.

  According to this embodiment, since the flexible wiring board 1 can be directly connected to the printed circuit board 6 without using a contact sheet or a connector, it is possible to further reduce the height.

  Further, the conductor pattern 3 can be reliably brought into contact with the ball-shaped electrode 9 by the elasticity of the gel layer 4.

  Further, since the through hole 11 can be widened by the slit 12, the flexible wiring board 1 and the printed board 6 can be easily connected and disconnected.

  Further, since the ball-shaped electrode 9 is adopted as the protruding electrode of the printed circuit board 6, when the flexible wiring board 1 is connected to the printed circuit 6, the peripheral portion of the through hole 11 can be bent toward the printed circuit board 6. The ball-shaped electrode 9 and the conductor pattern 3 can be brought into contact with each other more reliably.

  In this embodiment, the gel layer 4 is provided on the back surface of the insulating substrate 2, but a sheet-like elastic member such as an elastomer may be provided instead of the gel layer 4. However, although it is desirable to provide the gel layer 4 and the elastic member on the back surface of the insulating substrate 2, it is not an indispensable element.

  Further, although the ball-shaped electrode 9 is provided on the printed circuit board 6, the protruding electrode is not limited to the ball-shaped electrode 9. For example, a hemispherical shape, an inverted truncated cone shape, an inverted quadrangular truncated cone shape, etc. But you can.

  FIG. 6 is a sectional view of a flexible wiring board according to the second embodiment of the present invention.

  Constituent parts common to the first embodiment are denoted by the same reference numerals, description thereof is omitted, and only different constituent parts are described.

  In the flexible wiring board 201 of the second embodiment, the insulating substrate 202 includes a first insulating substrate 221 and a second insulating substrate 225.

  A plurality of holes 222 and recesses 223 are formed in the first insulating substrate 221. The hole 222 corresponds to the hole 21 of the flexible wiring board 1 of the first embodiment. The recess 223 surrounds the hole 222.

  A plurality of holes 226 and recesses 227 are formed in the second insulating substrate 225. The hole 226 corresponds to the hole 21 of the flexible wiring board 1 of the first embodiment. The recess 227 surrounds the hole 226. A housing space 229 is formed by the opposing recess 227 and recess 223.

  The gel layer 204 is accommodated in the accommodation space 229. The gel layer 204 is formed with holes 241 facing the holes 222 and 226. A through hole 211 is formed by the holes 222, 226, and 241. The through hole 211 corresponds to the through hole 11 of the flexible wiring board 1 of the first embodiment.

  The slit 212 extends from the conductor line 31 to the second insulating substrate 225.

  According to the second embodiment, the same effect as that of the first embodiment is achieved, and the gel layer 204 is sandwiched between the first and second insulating substrates 221 and 225. There is no risk of peeling from the insulating film 202.

FIG. 1 is a perspective view of a flexible wiring board according to the first embodiment of the present invention. FIG. 2 is a perspective view of a printed circuit board which is a counterpart connection object of the flexible wiring board shown in FIG. FIG. 3 is a sectional view showing a state before the flexible wiring board is connected to the printed circuit board. FIG. 4 is a cross-sectional view showing a state in which the through hole of the flexible wiring board is widened by the ball-shaped electrode of the printed circuit board. FIG. 5 is a cross-sectional view showing a state in which the flexible wiring board is connected to the printed board. FIG. 6 is a sectional view of a flexible wiring board according to the second embodiment of the present invention.

Explanation of symbols

1,201 Flexible wiring board 2 Insulating substrate 21 Hole 3 Conductor pattern 4,204 Gel layer 41,241 Hole 11,21 Through hole (hole)
12,212 Slit 6 Printed circuit board (object to be connected)
7 Insulating substrate 8 Conductor pattern 9 Ball electrode (projection electrode)
202 Insulating substrate 221 First insulating substrate 222 Hole 223 Recess 225 Second insulating substrate 226 Hole 227 Recess 229 Housing space

Claims (4)

An insulating substrate having flexibility;
In a flexible wiring board provided with a conductor pattern formed on the surface of this insulating substrate,
A flexible wiring board, wherein a hole for receiving a protruding electrode of a counterpart connection object is formed on the conductor pattern so as to penetrate the insulating substrate.   The flexible wiring board according to claim 1, wherein a gel layer is formed on a back surface of the insulating substrate.   The flexible wiring board according to claim 1, wherein a gel layer is formed inside the insulating substrate, and the holes penetrate the gel layer.   The flexible wiring board according to claim 1, wherein slits are formed radially around the hole.

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