JP2002353571A - Structure for wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring structure for wiring board, that is built to mount a standard circuit separately from another circuit, by utilizing both surfaces of one metallic substrate having a noise-resisting function in electronic equipment. SOLUTION: The connecting end sections 44 of the wiring board sections 40a of flexible printed wiring boards 40, placed side by side to each other on the surface of the backing substrate 30 of a gauge are extended through the slit-like opening 30a of the substrate 30. The extended connecting end sections 44 are respectively connected to the connecting end sections 133 of flexible printed wiring boards 120 and 130 laminated upon the rear surface of the backing substrate 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board structure of an instrument, for example.

[0002]

2. Description of the Related Art In recent years, for example, in passenger cars, short-term development of new models has been demanded.
Usually, the specifications of the meter are changed, and the structure of the wiring board is also changed. Further, in recent years, since the instrument has been required to have more advanced functions, there is a tendency to adopt a wiring board structure equipped with a microcomputer having a CPU.

[0003]

By the way, in the above-mentioned wiring board structure of the instrument, if the circuit layout of the wiring board is changed every time the specification of the meter is changed, the noise resistance of the meter is changed every time this change is made. It is necessary to check the adverse effect of radio waves on other electric devices such as radio and radio, which delays the short-term development of new models. Further, in order to cope with the increase and complexity of the circuit having the wiring board structure due to the above-described change in the circuit layout and the high performance of the instrument, a plurality of large wiring boards are required. Therefore, when the wiring board is a wiring board having a rigid board, a large rigid board is additionally required as a base board, which increases the space for the wiring board structure and increases the cost.

[0004] On the other hand, the present inventors have studied the wiring board structure of the meter. When the specifications of the meter are changed, the circuit of the wiring board has a circuit other than a circuit whose layout must be changed. Regardless of the change in the instrument specifications, he recognized that standard circuits common to various instruments were also included.

In view of the above, in the present invention, a standard circuit is mounted separately from other circuits using both surfaces of a single metal substrate having a noise resistance function in an electronic device. An object of the present invention is to provide a wiring structure of a wiring board.

[0006]

In order to achieve the above object, in the wiring board structure according to the first aspect of the present invention, a metal substrate (30) and a flexible printed wiring provided along the surface of the metal substrate along the surface thereof are provided. Board (40) and a printed wiring board (120, 1
30), the metal substrate is provided with openings (30a, 30a).
b), the flexible printed wiring board is cut out in the form of a tongue at an intermediate portion thereof, and extends to the back side of the metal substrate through the opening (40).
a, 40b), and the printed wiring board has
The connection ends (133, 134) are electrically connected to the extended connection ends (44, 45) of the wiring board.

By connecting the flexible printed wiring board to a large number of circuits required by the specifications specific to the electronic equipment using the flexible printed wiring board, the printed wiring board on the back side has the same specifications as the electronic equipment. Regardless, a standard circuit common to various electronic devices is connected, and the front-side flexible printed wiring board and the back-side printed wiring board are electrically connected to each other through a backing substrate with a wiring board portion.

Therefore, it is not necessary to change the layout of the printed wiring board, and only the circuit of the front-side flexible printed wiring board which is required according to the specifications specific to the electronic device is changed. The change can be suppressed to the minimum necessary. Moreover, since the backing substrate is used as a rigid base substrate in the above-mentioned wiring board structure on the premise that the backing substrate exhibits a noise-resistant function together with the front-side flexible printed wiring board, the noise resistance of electronic devices and radio As a result, it is not necessary to reconfirm the noise resistance of the electronic device or the adverse effect of the radio wave on other electric devices such as a radio. Therefore, even if the electronic device is used for a new model, short-term development of the new model is not delayed.

Further, since the wiring board structure is secured by using only one backing substrate as a rigid base substrate as described above, it is possible to prevent an increase in the space for the wiring board structure and the accompanying increase in cost. it can.

According to a second aspect of the present invention, in the first aspect of the present invention, the printed wiring board includes a CP.
It is a flexible printed wiring board smaller than a flexible printed wiring board formed by wiring a standard circuit (130a) having U. This allows
The operation and effect of the invention described in claim 1 can be further improved.

In the wiring board structure according to the third aspect of the present invention, a backing substrate (30) made of a metal material provided on the instrument and a specification change of the instrument provided alongside the surface of the backing substrate along the surface are provided. Front side flexible printed wiring board (40) formed by connecting a number of circuit elements according to the wiring
A back side flexible printed circuit board (120, 130) smaller than a front side flexible printed circuit board formed by connecting a standard circuit (130a) of an instrument having a CPU, which is provided along the back surface of the backing substrate and connected thereto; The backing substrate has openings (30a, 30b), and the front-side flexible printed wiring board is cut out and formed in a tongue shape at an intermediate portion thereof, and the opening is formed on the back side of the backing substrate. Through the wiring board portion (40a,
40b), and the flexible printed wiring board on the back side is connected at its connection ends (133, 134).
It is electrically connected to the extended connection end (44, 45) of the wiring board.

Thus, the front-side flexible printed wiring board having a large number of circuits required by the instrument-specific specifications and the back-side flexible printed wiring having a standard circuit common to various instruments irrespective of the instrument specifications Board and
With the wiring board portion, electrical connection is made through the backing substrate.

Therefore, it is not necessary to change the layout of the flexible printed wiring board, and only the circuit of the front side flexible printed wiring board which is required according to the specifications specific to the instrument is changed.
The change can be suppressed to the minimum necessary. Moreover, since the backing substrate is used as a rigid base substrate in the above-mentioned wiring board structure on the premise that the backing substrate exhibits a noise-resistant function together with the front-side flexible printed wiring board, the noise-resistance of the instrument, radio, etc. The elimination of adverse effects of radio waves on other electrical devices can be inevitably secured, and as a result, there is no need to confirm again the noise resistance of the instrument and the adverse effects of radio waves on other electrical devices such as radio. Therefore, even if the instrument is used in a new model, the short-term development of the new model will not be delayed.

Further, as described above, since the wiring board structure is ensured by using only one backing substrate as a rigid base substrate, an increase in the thickness of the wiring board structure and an increase in cost associated therewith are required. Can be prevented.

[0015] The reference numerals in parentheses of the above means indicate the correspondence with the specific means described in the embodiment described later.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an example in which the present invention is applied to a passenger car instrument. This instrument is provided as a speedometer on an instrument panel in the passenger compartment of the passenger car.
, A reflector 20, a backing substrate 30, and a flexible printed wiring board 40.

The return plate 10 is assembled at its base end to the annular frame 20a of the reflector 20 at its base end opening. The backing substrate 30 is made of an aluminum plate, and the backing substrate 30 is mounted on the outer peripheral portion of the flexible printed wiring board 40 at the distal end opening of the annular frame 20a of the reflector 20 via the outer peripheral portion. .

Thus, the backing substrate 30 plays a role as a back cover of the instrument and a role to constitute a casing together with the reflector 20. Further, since the backing substrate 30 is made of an aluminum plate, the backing substrate 30 also plays a role of satisfactorily releasing the heat inside the casing to the outside by a heat transfer action. In addition, the grounding of the backing substrate 30 also serves as an electromagnetic shield in combination with a configuration as a parallel plate capacitor described later.

The flexible printed wiring board 40 is of a single-sided type.
As shown in FIG. 1, it is provided on the backing substrate 30 along the surface thereof. The flexible printed wiring board 40
Is, as can be seen from FIGS. 1 and 2, the thermoplastic insulating film 4.
A plurality of copper foils 42 (only one copper foil is shown in FIG. 2) are formed on one surface. The flexible printed wiring board 40 has an insulating film 41 with a plurality of copper foils 42 positioned on the reflector 20 side.
Is uniformly adhered to the surface of the backing substrate 30 to form the parallel plate capacitor together with the backing substrate 30. That is, the parallel plate capacitor is formed by sandwiching the insulating film 41 as a dielectric between the plurality of copper foils 42 and the backing substrate 30.

The meter includes a light guide plate 50, a scale 60, a rotating inner device 70, and a light emitting pointer 80. The light guide plate 50 is made of a light conductive resin material. The light guide plate 50 is housed and held in the housing 21 formed on the reflection plate 20 b of the reflector 20. Scale plate 60
Is attached to the light guide plate 50 from the front side, and the scale plate 60 is provided at its outer peripheral portion with an annular support portion 11 extending from the dial plate 10 to the inside in an L-shaped cross section.
It is supported on the outer periphery of the light guide plate 50. The graduation plate 60 has a substantially arc-shaped graduation (not shown) for grading the vehicle speed of the passenger car along an outer peripheral portion thereof,
Each scale and number of this scale portion are transparent. The scale plate 60 is dark and opaque except for the scales and numbers of the scale portions.

As shown in FIG. 1, the rotating inner unit 70 includes an inner unit main body 71 and a pointer shaft 72.
Numeral 1 is supported by the backing substrate 30 from the back side at a position corresponding to the center hole 61 of the scale plate 60.
The pointer shaft 72 extends coaxially and rotatably from the inner machine main body 71 into the through hole 31 of the backing substrate 30, the through hole 43 of the flexible printed wiring board 40, and the cylindrical body 20 c of the reflector 20.

The luminous pointer 80 is coaxially supported by the boss 81a of the rotating base 81 at the tip of the pointer shaft 43 in the cylindrical body 20c. It is designed to rotate along. Also,
The light emitting pointer 80 emits light from a cylindrical light guide member 110 described later into the rotating base 81 and emits light at the pointer.

The instrument has a plurality of light emitting elements 9 for a scale.
0, the plurality of pointer light emitting elements 100, and the light guide member 1
10 is provided. Light emitting elements 90 for a plurality of dials
The plurality of flexible printed wiring boards 40 are arranged at intervals along the arc direction within the extended end opening 22a of the reflecting plate portion 22 having an eight-shaped cross section formed on the reflecting plate 20b of the reflector 20. The strip copper foil 42 is connected to the corresponding copper foil. As a result, each light emitting element 90 is supplied with power from the flexible printed wiring board 40 to emit light, and emits light into the reflection plate portion 22. In addition, each light emitting element 90 includes a light emitting diode and other light sources.

Here, the reflector 22 extends from the bottom wall of the housing 21 of the reflector 20b in the form of a tapered cross section toward the back surface thereof, and a flexible printed wiring is formed at the extension end opening 22a. The reflecting plate portion 22 is seated on the surface of the plate 40, and is formed in an arc shape on the bottom wall portion of the housing portion 21 corresponding to the arc-shaped scale portion of the scale plate 60. As a result, the reflecting plate portion 22 enters the scale plate 60 from the back surface through the light guide plate 50 while reflecting the light emitted from each light emitting element 90.

The plurality of pointer light emitting elements 100 are formed by a plurality of openings formed in the bottom wall 25 of the cylindrical body 20c in the circumferential direction between the inner cylindrical wall 23 and the outer cylindrical wall 24 of the cylindrical body 20c of the reflector 20. Flexible printed wiring board 4 through section 25a
0 of the plurality of copper foils 42 are connected to the corresponding copper foils.
Light is emitted into c. In addition, each light emitting element 100 includes a light emitting diode and other light sources.

Here, the cylindrical body 20c has an outer cylindrical wall 24.
Is coaxially fitted into the through hole 51 of the light guide plate 50 at the front end opening thereof, and the cylindrical body 20c is attached to the bottom wall 25 thereof.
Is seated on the flexible printed wiring board 40. Further, the cylindrical body 20c is positioned so as to coaxially surround the pointer shaft 72 and the boss 81a of the light emitting pointer 80 from outside on the inner cylindrical wall 23 thereof.

The cylindrical light guide member 110 is accommodated coaxially between the inner cylindrical wall 23 and the outer cylindrical wall 24 of the cylindrical body 20c.
At the end of the outer peripheral wall 24, the outer periphery of the through hole 61 of the scale plate 60 is seated at the distal end opening of the outer cylindrical wall 24, and the distal end 112 faces each light emitting element 100. As a result, the light guide member 110 receives light from each light emitting element 100 at its tip 112 and guides the light in the axial direction, thereby causing the light emitting pointer 8 to emit light.
The light enters the zero rotation base 81.

The instrument has two single-sided flexible printed wiring boards 120 and 130 having a surface area considerably smaller than that of the flexible printed wiring board 40.
Both of these flexible printed wiring boards 120 and 130 have the same square thin plate shape. The flexible printed wiring board 130 is connected to the inner machine main body 71 and a connector 1 described later.
40, and is laminated on the back surface of the backing substrate 30 via the flexible printed wiring board 120.

As shown in FIGS. 1 and 3, the flexible printed wiring board 120 is formed by forming a plurality of copper foils 122 on the surface of a thermoplastic insulating film 121. The insulating film 121 is uniformly adhered to the back surface of the backing substrate 30 so that the plurality of copper foils 121 are positioned on the flexible printed wiring board 130 side.

On the other hand, the flexible printed wiring board 130
Is a thermoplastic insulating film 13 as shown in FIGS.
The flexible printed wiring board 130 is formed by forming a plurality of copper foils 132 on the surface of one, so that the plurality of copper foils 131 are located on the opposite side of the flexible printed wiring board 120, The backing substrate 3 is formed on the insulating film 131 via the flexible printed wiring board 120.
0 is attached to the back surface.

Here, the connection configuration of the flexible printed wiring board 130 and the flexible printed wiring board 40 via the backing substrate 30 will be described. Backing substrate 30
As shown in FIG. 1 and FIG.
0b, and each of these openings 30a, 30b
As shown in FIG. 3, slits are formed in the center of the backing substrate 30 in parallel with each other.

The opening 30a is located near the lower side of the one end 123 of the flexible printed wiring board 120 as shown in FIG. 1 and is parallel to the end surface of the one end 123. In the vicinity of the upper side of the other side end 124 of the flexible printed wiring board 120 in FIG.
4 is located parallel to the end face. However, the opening 30a
Has an opening shape similar to the cross-sectional shape of the wiring portion 40a,
Further, it has an opening surface wider than the cross section of the wiring portion 40a. On the other hand, the opening 30b has an opening shape similar to the cross-sectional shape of the wiring portion 40b, and has an opening surface wider than the cross-section of the wiring portion 40b.

The flexible printed wiring board 40 is shown in FIG.
3, as shown in FIG. 3, both wiring board portions 40a and 40b are provided. The wiring board portion 40a is formed in a tongue shape by cutting out the flexible printed wiring board 40 from the portion corresponding to the opening portion 30a of the backing substrate 30 upward in FIG. As shown in FIGS. 1 and 2, the backing substrate 30 passes through the opening 30a.
Of the flexible printed wiring board 130 at the extended connection end 44 thereof.
The top is electrically connected. This connection is made by soldering each copper foil portion of the extended connection end portion 44 to each copper foil portion of the one-side connection end portion 133.

On the other hand, the wiring board portion 40b is
The flexible printed wiring board 40 is cut out from the part corresponding to the opening 30b of FIG.
As shown by, it extends to the back side of the backing substrate 30 through the opening 30b and is electrically connected to the other connection end 134 of the flexible printed wiring board 130 at the extension connection end 45. Have been. This connection is made by soldering each copper foil portion of the extended connection end portion 45 to each copper foil portion of the other connection end portion 134.

In the present embodiment, the flexible printed wiring board 40, the backing substrate 30, and the two flexible printed wiring boards 120 and 130 configured as described above provide the wiring board structure of the instrument. The flexible printed wiring board 40 is a semiconductor chip 40 determined by the specifications of the instrument.
c (see FIG. 3), and a number of other circuit elements,
These circuit elements are connected to corresponding copper foils of the plurality of copper foils 42 of the flexible printed wiring board 40 by soldering.

The flexible printed wiring board 130
Has a standard circuit common to various instruments including a semiconductor chip 130a (see FIG. 3) having a main component CPU of a microcomputer, and the standard circuit includes a plurality of copper foils 132 of a flexible printed wiring board 130. Are connected to corresponding copper foils by soldering. However, since the above standard circuit has many connection terminals,
The standard circuit is connected using not only each copper foil of the flexible printed wiring board 130 but also each copper foil of the flexible printed wiring board 120 which is connected to the flexible printed wiring board 130 through the interlayer.

The connector 140 is supported by the back end of the backing substrate 30, and each terminal pin of the connector 140 passes through the backing substrate 30 to a corresponding copper foil of the plurality of copper foils 42 of the flexible printed wiring board 40. It is connected to the foil by soldering. This connector 140
Is connected to a connector 150 of an external circuit.

In this embodiment constructed as described above, as described above, the backing substrate 30 serving as the back cover of the instrument is used, and the flexible printed wiring board 40 is also provided on the front side of the backing substrate 30. Then, both flexible printed wiring boards 12
0, 130 are provided side by side in a laminated manner, and the respective wiring board portions 40a, 40b of the flexible printed wiring board 40 are inserted into the respective openings 30a, 30b of the 30 to the back side. Then, the respective wiring board portions 40a, 40b are connected to the respective connection end portions 133, 134 on one side and the other side of the flexible printed wiring board 130 at the respective extended connection end portions 44, 45 on one side and the other side. .

As a result, the flexible printed wiring board 40 having a circuit required by the specification specific to the instrument and the flexible printed wiring boards 120 and 130 having a standard circuit common to various instruments regardless of the specification of the instrument. With the wiring board portions 40a and 40b,
0 is electrically connected.

Accordingly, both flexible printed wiring boards 1
It is not necessary to change the layout of the circuits 20 and 130, and only the circuit of the flexible printed wiring board 40 which is required according to the specifications specific to the instrument is changed, so that the change is minimized. Can be suppressed. In addition, as described above, the backing substrate 30, which exhibits the noise resistance function together with the flexible printed wiring board 40, is used as the rigid base substrate in the wiring board structure. As a result, it is not necessary to confirm again the adverse effect of the radio wave on other electrical devices such as a radio and the noise resistance of the instrument. Therefore, even if the instrument is used in a new model, the short-term development of the new model will not be delayed.

Further, as described above, since the wiring board structure is secured by using only one backing substrate 30 as a rigid base substrate, an increase in the space for the wiring board structure and the accompanying cost increase. Can be prevented.

In practicing the present invention, the present invention is not limited to an instrument for passenger cars, but may be applied to an instrument for automobiles and other vehicles in general. Further, the present invention is not limited to the vehicular instrument, and even if the wiring board structure is configured using a metal substrate having noise resistance of the meter and other various electronic devices, substantially the same operation and effect as in the above embodiment can be obtained. Can be achieved.

In implementing the present invention, each of the flexible printed wiring boards 120 and 130 is considerably smaller than the flexible printed wiring board 40, and therefore may be a rigid printed wiring board.

In practicing the present invention, if the number of connection terminals of the standard circuit is not so large, the flexible printed wiring board 120 may be omitted.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view of the embodiment.

FIG. 3 is an exploded perspective view of each flexible printed wiring board and a backing substrate of FIG. 1;

[Explanation of symbols]

Reference numeral 30: backing substrate, 30a, 30b: opening, 40, 1
20, 130 ... flexible printed wiring board, 40a,
40b: wiring board part, 44, 45 ... extension connection end part, 130
a: semiconductor chip, 133, 134: connection end.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5E338 AA02 AA03 AA05 AA12 AA16 AA18 BB02 BB17 BB52 BB54 BB63 BB75 CC01 CD05 CD08 CD32 CD40 EE13 5E344 AA02 AA12 AA19 AA22 BB02 BB03 BB04 CC13 BB09 CC13 DD13 CC13 5E346 AA03 AA12 AA15 AA22 AA35 AA41 BB01 CC02 CC08 CC31 EE44 FF22 GG28 HH01

Claims (3)

[Claims] 1. A metal substrate (30), a flexible printed wiring board (40) provided along the surface of the metal substrate, and a printed wiring board (120, 130) provided along the back surface of the metal substrate. Wherein the metal substrate has openings (30a, 30b), and the flexible printed wiring board is cut and formed in a tongue shape at an intermediate portion thereof, The wiring board portion (40a, 40a) extended through the opening
b), and the printed wiring board has connection ends (133, 13).
At 4), the extended connection end portions (44, 45) of the wiring board portion
Wiring board structure electrically connected to 2. The printed wiring board according to claim 1, wherein the printed wiring board is a flexible printed wiring board smaller than the flexible printed wiring board formed by wiring a standard circuit having a CPU. Wiring board structure. 3. A backing substrate (30) made of a metal material provided on an instrument, and a front side provided with a plurality of circuit elements connected to the backing substrate along the surface thereof in accordance with a change in specification of the instrument. A back side flexible board smaller than the front side flexible printed board board which is connected to a flexible printed wiring board (40) and a standard circuit (130a) of an instrument having a CPU which is provided along the back side of the backing board and has a CPU; A printed wiring board (120, 130), wherein the backing substrate has openings (30a, 30b), and the front side flexible printed wiring board is cut out in a tongue shape at an intermediate portion thereof. And a wiring board portion (40) extended to the back side of the backing substrate through the opening.
a, 40b), and the back side flexible printed wiring board is electrically connected to the extended connection ends (44, 45) of the wiring board at the connection ends (133, 134). Wiring board structure that is electrically connected.