JPH0661591A - Flexible wiring board and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a FPC which can prevent floating from the mounting surface and pasted together with the mounting surface in a close adhesion state. CONSTITUTION:A conductor circuit having a prescribed pattern is formed on a thin film insulating board 14 while solidifying an FPC (flexible wiring board) 25 to be pasted together with the mounting surface 3 of a meter main body 7 to the final mounting form.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible wiring substrate in which a conductor circuit having a predetermined pattern is formed on a thin insulating substrate, and a method for manufacturing the same.

[0002]

2. Description of the Related Art As a wiring substrate, a flexible wiring substrate (flexible printed circuit board, hereinafter referred to as "FPC") in which a conductor circuit having a predetermined pattern is formed on a thin film insulating substrate is widely used (special feature). Kaisho 63-298986
JP, JP-A-2-299294, JP, 3-6
No. 2470, Japanese Patent Laid-Open No. 3-101008).

This FPC is an insulating substrate on the surface of a base film made of polyester with a thickness of about 0.1 mm.
As a conductive member formed in a predetermined pattern, a thickness of about 35
A copper foil of μ is formed by a wet etching method.

This FPC has excellent flexibility, has a high degree of freedom in bending, and can be attached to an uneven mounting surface, so that the FPC has a higher degree of freedom in mounting than other wiring boards (HPC, etc.). high.

An FPC in which a wiring circuit for connecting a device incorporated in a meter of an automobile and external wiring is formed as a conductive circuit will be described below.

FIG. 9 shows a meter 1 incorporated in an instrument panel of an automobile and an FPC 5 mounted on a mounting surface 3 on the back side of the meter 1. Meter 1
Includes a box-shaped meter body 7, a plurality of devices (not shown) incorporated in the meter body 7, and a front transparent cover 9 that closes the front surface of the meter body 7. Meter body 7
The mounting surface 3 on the back surface side of A has a surface A, a surface B protruding from the surface A, and a step C connecting the surfaces A and B. A
A plurality of protrusions 11 are provided on the outer peripheral portion of the surfaces B and B,
A mating connector connecting recess 1 in which a mating connector (not shown) and the FPC 5 are connected to each other at substantially central portions of the A and B surfaces.
5 are formed respectively.

On the other hand, the FPC 5 is a surface A of the meter body 7,
Of the thin film in which the a-face and the b-face which are respectively attached to the B-face and the bent portion 17 which is attached to the stepped portion C of the meter body between the a-face and the b-face are integrally formed It is composed of an insulating substrate 14 and a wiring circuit formed of a copper foil 16 on the insulating substrate 14. Further, a plurality of through holes 19 are formed on the outer peripheral portion of the insulating substrate 14 so as to correspond to the protrusions 11.
Connector connecting portions 23 are respectively formed in substantially central portions of the surfaces a and b.

To bond the FPC 5 to the back side of the meter main body 7, the a surface is overlaid on the A surface of the meter main body 7, the b surface is overlaid on the B surface, and the bent portion 17 is aligned with the step C. Then, the projection 11 is inserted into the through hole 19, and the fixed cap 13 is fitted to the tip portion thereof. As a result, the FPC 5 is attached and fixed to the mounting surface 3 on the rear surface side of the meter body 7.

By using such an FPC 5,
Troublesome wiring work is eliminated, incorrect wiring is prevented, and wiring work is simplified. Further, since the thin-film FPC 5 is attached to the back surface side of the meter body 7, the space efficiency on the back surface side of the meter body 7 is improved. Further, since the space on the back side of the meter body 7 is widened, the maintainability is improved. Further, the use of the FPC 5 prevents the generation of noise due to vibration.

[0010]

[Problems to be Solved by the Invention] However, the FPC
Since 5 is partially fixed to the mounting surface 3 (through hole 19 into which the protrusion 11 is inserted), the FPC 5 is provided between the protrusions 11.
Cannot be adhered to the mounting surface 3 in close contact,
As shown in FIGS. 10A and 10B, the gap 2 is formed between the protrusions 11.
1 occurs and so-called floating occurs. When the meter 1 is assembled to the instrument panel in this state, the FPC 5 may interfere with other components and the FPC 5 may break. In particular, in the bent portion 17 attached to the stepped portion C, since the fixed portions are long and the adhesion is poor, there is a possibility that a crack D may enter from the corner portion as shown in FIG.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a flexible wiring board which can prevent the body to be mounted from floating from the mounting surface and can be adhered to the mounting surface in a close contact state, and a manufacturing method thereof. .

[0012]

The present invention has been made in consideration of the above circumstances, and has a solidification means for solidifying a thin film insulating substrate and a conductor circuit in a final mounting shape of a mounting surface of a mounted body. Is characterized by.

According to a second aspect of the present invention, a conductor circuit having a predetermined pattern is formed on a thin film insulating substrate, and the conductor circuit is attached to a supporting jig having a supporting surface having the same shape as the mounting surface of the mounted body, It is characterized in that the insulating substrate and the conductor circuit are solidified into the final mounting shape of the mounting surface of the mounted body.

[0014]

According to the first aspect of the present invention, since the flexible wiring board is solidified in advance to the final mounting shape by the solidifying means, it is adhered to the mounting surface of the mounted body in a close contact state.

According to the second aspect of the present invention, the thin-film insulating substrate on which the conductor circuit having the predetermined pattern is formed is attached to a supporting jig having a supporting surface having the same shape as the mounting surface of the mounted body. , Solidify to the final mounting shape of the mounting surface of the mounted body. When this flexible wiring board is attached to the attachment surface, the flexible wiring board is adhered to the attachment surface of the object to be attached.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. The same components as those of the FPC 5 and the meter 1 shown in FIG. 9 will be described using the same reference numerals.

First Embodiment FIG. 1A shows an FPC (flexible wiring board) of the first embodiment.
25 and the meter 1 in which the FPC 25 is attached to the back surface side. In the figure, the FPC 25 of the present embodiment is the mounting surface 3 of the meter body 7 to which the FPC 25 is attached.
Is formed (final mounting shape). That is,
As shown in FIG. 1B, the copper foil 16 forming the connection circuit (conductive circuit) is provided with a metal coating 27 which is a solidifying means in a state of being formed into the final mounting shape. As a result, the FPC 25 is solidified into the shape of the mounting surface 3 of the meter body 7.

When such an FPC 25 is attached to the mounting surface 3 of the meter body 7, no floating occurs between the projections 11, and the bent portion 17 is also attached to the step portion C in a close contact state as shown in FIG. To be done.

Next, a method of manufacturing the FPC 25 will be described with reference to FIGS.

As shown in FIG. 3A, a thin film insulating substrate 14 having an area substantially equal to the total surface area of the mounting surface 3 (A surface, B surface, step C) is formed. Then, a wiring circuit of a predetermined pattern made of the copper foil 16 is formed on the insulating substrate 14. A wet etching method is used to form a connection circuit made of the copper foil 16. In this wet etching method, after a copper foil is entirely deposited on the insulating substrate 14 by means such as vacuum deposition, a mask having the same shape as the conductor circuit pattern is formed on the copper foil 16 by an etching resist agent. Then, the copper foil 16 in the non-masked portion is dissolved and removed by etching to form a conductor circuit having a predetermined pattern by the copper foil 16 on the insulating substrate 14. The FPC 25 on which the conductive circuit is formed in this manner has excellent flexibility and has a high degree of bending flexibility.

On the other hand, as shown in FIG. 3B, a supporting jig 29 having a supporting surface 31 having the same shape as the mounting surface 3 (final mounting shape) on the rear surface side of the meter body 7 is formed. And
A plurality of protrusions 11 ′ are provided so as to project from the support surface 31 in correspondence with the through holes 19 of the FPC 25 having a high degree of bending freedom.
Connection recesses 15 'and 15' are formed in portions of the PC 25 corresponding to the connector connecting portions 23, respectively.

Then, as shown in FIG. 3C, the FPC 25 having a high degree of freedom in bending is attached to the support surface 31 of the support jig 29, and the projections 11 'are inserted into the through holes 19, respectively.
The fixed cap 13 is fitted to the tip portion thereof. Further, dummy connectors 33, 33 having the same shape as the counterpart connector are inserted into the connector connecting portions 23, 23, respectively. As a result, the FPC 25, which has a high degree of freedom in bending, is attached to the support jig
The support surface 31 is adhered to the support surface 31.

Next, as shown in FIG. 4A, a metal coating 27 is formed on the copper foil 16 forming the conductive circuit of a predetermined pattern by electroless plating. That is, the copper foil 16
In a state where the insulating substrate 14 other than the above is shielded by the mask 47, the supporting jig is immersed in an electroless plating bath, and the metal film 27 is laminated on the copper foil 16. This electroless plating treatment is also called chemical plating treatment and is a known plating method utilizing reduction by the contact action of the material surface (copper foil 16 surface) and is different from the electroplating method.

The laminated metal coating 27 is shown in FIG.
As shown in (a), since the bent portion 17 is also formed on the copper foil 16, the shape of the bent portion 17 is solidified. After forming the metal coating 27 on the copper foil 16, as shown in FIG.
As shown in (b), the FPC 25 is removed from the support jig 29 and the mask is removed. This allows the FPC25
Is solidified into the final mounting shape (mounting surface 3 of the meter body 7).

In this embodiment, by forming a metal coating on the copper foil 16, it becomes possible to flow a large current through the copper foil 16 without expanding the area of the copper foil 16. That is, it is sufficient to make the copper foil 16 thick in order to flow a large current through the copper foil 16 forming the conductive circuit of a predetermined pattern.
Since the PC 25 has a low degree of bending freedom, the pattern width of the copper foil 16 is widened while maintaining the thickness of the copper foil 16 to secure the cross-sectional area. However, if the pattern width of the copper foil 16 is increased, the area of the entire conductive circuit is increased, and the FPC
25 becomes large.

However, in the FPC 25 of this embodiment, since the metal film 27 is formed on the copper foil 16 in the final mounting shape, it is possible to handle a large current without increasing the area of the base of the copper foil 16. It will be possible. Also, copper foil 1
By partially changing the thickness of the metal coating 27 applied to 6, it is possible to make only the necessary conductive circuit for large current.

Second Embodiment Next, the FPC 35 of the second embodiment and its manufacturing method will be described with reference to FIG. The FPC of the second embodiment is also the first
Like the FPC 25 of the embodiment, it is attached to the mounting surface 3 on the back side of the meter body 7 of the automobile.

In the FPC 35 of the second embodiment, as shown in FIG. 5, an epoxy resin 41, which is a solidifying means, is applied to the outer peripheral edge of the thin insulating substrate 14 to bond the FPC 35 to the meter main body 7. Is solidified to the shape of the mounting surface 3 (final mounting shape).

When such an FPC 35 is attached to the mounting surface 3 of the meter main body 7, no floating occurs between the protrusions 11 and the bent portion 17 is also attached to the step portion C in a close contact state.

Next, a method of manufacturing the FPC 35 will be described with reference to FIGS.

First, as in the first embodiment described above, a thin film insulating substrate 14 having an area equal to the surface area of the mounting surface 3 of the meter body 7 is formed. Then, a conductive circuit having a predetermined pattern is formed on the insulating substrate 14 by the wet etching method using the copper foil 16 to form the FPC 35 having a high degree of bending freedom.

On the other hand, as shown in FIG. 6, a supporting jig 29 having a supporting surface 31 having the same shape as the mounting surface 3 (final mounting shape) on the back side of the meter body 7 is formed. In this case, a plurality of protrusions 11 ′ are provided so as to project from the support surface 31 corresponding to the fixing through holes 19 of the FPC 35 having a high degree of bending freedom. Further, a mating connector connecting recess 15 'is formed in a portion of the FPC 35 corresponding to the connector connecting portion 23.

Further, as shown in FIG. 7A, the supporting surface 3
A pressing jig 37 that fits on the 1 is formed. The holding jig 37 has a plurality of through holes 39 corresponding to the outer peripheral portion of the FPC 35.

After the FPC 35 having a high degree of bending flexibility is attached to the support surface 31 of the support jig 29, the back side of the FPC 35 is supported by the holding jig 37 to support the support jig 29.
And the holding jig 37. This allows the FPC
35 is attached to the support surface 31 of the support jig 29 in a close contact state.

Next, as shown in FIG. 7B, an epoxy resin 41 is injected from a through hole 39 provided in the holding jig 37 by a tube 43 or the like, coated on the insulating substrate 14, dried and solidified. Let In addition, as shown in FIG. 8, the holding jig 37 corresponding to the bent portion 17 is formed with rectangular bent portion resin coating holes 45 at the corners, and the bent portion resin coating hole 45 is formed. , 45 to epoxy resin 14
Inject on. After the epoxy resin 41 is solidified, the holding jig 37 is removed, and the FPC 35 is removed from the supporting jig 29. In this state, the FPC 35 is solidified into the shape of the mounting surface of the meter body 7 (final mounting shape).

According to the method of manufacturing the FPC 35 of the second embodiment, the weight (epoxy resin) can be formed as compared with the FPC 25 of the first embodiment described above.

[0037]

As described above, according to the flexible wiring board and the method for manufacturing the same according to the present invention, the flexible wiring board is solidified into the final mounting shape so that the mounting surface of the body to be mounted is removed. It can be attached to the mounting surface in a tightly adhered state by preventing it from floating. Therefore, breakage of the flexible wiring board due to external interference can be prevented.

[Brief description of drawings]

FIG. 1 is a perspective view showing an FPC according to a first embodiment of the present invention, and FIG. 1 (b) is a sectional view taken along line bb of FIG.

FIG. 2 is a partially enlarged perspective view of the back side of the FPC and the meter body of the first embodiment of the present invention.

3A and 3B show a method for manufacturing an FPC according to a first embodiment of the present invention, FIG. 3A is a front view showing an FPC in which a conductive circuit having a predetermined pattern is formed on an insulating substrate, and FIG. It is a perspective view showing a support jig having the same support surface as
(C) is a perspective view showing a state in which the FPC is attached to the support jig.

FIG. 4 shows the FPC and supporting jig of the first embodiment (a).
FIG. 3B is a cross-sectional view showing a state where the FPC copper foil is plated, and FIG. 6B is a cross-sectional view showing a state where the FPC in the state where the copper foil is plated and solidified is removed from the support jig. Is.

FIG. 5 is a perspective view showing an FPC and a meter body of a second embodiment of the present invention.

FIG. 6 is a perspective view showing the FPC manufacturing method according to the second embodiment of the present invention and showing the FPC and the support jig 29 having a high degree of bending freedom.

FIG. 7 shows a supporting jig, a holding jig, and an FPC having the same supporting surface as the final mounting shape, and FIG. 7A is a perspective view showing a state in which the FPC is attached to the supporting surface of the supporting jig,
(B) is a perspective view showing a state in which the FPC is clamped by a supporting jig and a holding jig.

FIG. 8 is a perspective view showing a supporting jig and a holding jig for a bent portion and a step portion.

FIG. 9 is a perspective view showing a conventional FPC and a meter to which the FPC is attached.

FIG. 10 shows a part of an FPC attached to a meter, (a) is a perspective view, (b) is a cross-sectional view, and (c).
FIG. 4 is a perspective view showing a bent portion.

[Explanation of symbols]

 3 Mounting surface 7 Meter main body (attached body) 14 (Thin film) insulating substrate 16 Copper foil 17 Bending portion 25, 35 FPC (Flexible wiring board) 27 Metal coating 29 Support jig 31 Support surface 37 Holding jig 41 Epoxy resin

─────────────────────────────────────────────────── ───Continued from the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication H05K 7/14 T 7301-4E

Claims (2)

[Claims] 1. A flexible wiring board in which a conductor circuit having a predetermined pattern is formed on a thin-film insulating substrate and is bonded to a mounting surface of a mounted body, the final mounting shape of the mounting surface of the mounted body. A flexible wiring board having a thin film insulating substrate and solidifying means for solidifying the conductor circuit. 2. A conductive circuit having a predetermined pattern is formed on a thin-film insulating substrate, and the conductive circuit is attached to a supporting jig having a supporting surface having the same shape as the mounting surface of the mounted body to attach the mounted surface of the mounted body. A method for manufacturing a flexible wiring board, characterized in that the insulating board and the conductor circuit are solidified into a final mounting shape.