JPH0432290A - Solid wiring circuit board - Google Patents

Abstract

PURPOSE:To get a solid wiring circuit board, which is equipped with a specified conductor pattern and is excellent in self recovery and elasticity, by adding inorganic fillers, glass simple fibers, and flame retarders to thermoplastic and highly viscous polyester resin excellent in heat resistance, and kneading it, and extrusion-molding it to form a sheet-shaped insulating board in amorphous condition, and forming a specified conductor pattern, and then bending it optionally. CONSTITUTION:Inorganic fillers, glass fibers, and flame retarders are added to thermoplastic and highly viscous saturated polyester resin excellent in heat resistance, and it is kneaded, and then it is extruded continuously into a sheet- shaped one of specific thickness (approximately 1.2mm) to make an insulating substrate. After a thin part 13 is formed at the part corresponding to the bend 12 of a circuit board 10a, this circuit board 10 is put in a heating furnace, and is heated for about thirty minutes at the temperature of about 130 deg.C to crystallize an amorphous insulating board, which constitutes a circuit board 10a, about 15-20%, whereby the tenacity at the bend 12 of the circuit board 10a is relaxed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to various electronic devices such as communication and video devices, as well as
It relates to a three-dimensional wiring circuit board that is highly elastic and can be bent into any shape and can be used in electronic instruments installed in automobiles, aircraft, etc., and its purpose is to convert the circuit board into electronic devices. By mounting the circuit board in accordance with the shape of the outer shell, the dead space at the mounting location of the circuit board can be effectively utilized, thereby making the electronic device lighter, thinner, shorter and smaller, and reducing the number of parts to be mounted.

[Conventional technology]

In recent years, for various electronic devices such as communication and video equipment, there has been a demand for smaller size, higher performance, and multi-functionality of the devices themselves, and the printed wiring boards used in each of the devices have also become more densely wired and circuits. Naturally, measures such as miniaturization will be necessary. The printed wiring board is usually formed into a flat shape, and unless there is sufficient space for mounting the wiring board, for example, a single flat printed wiring board on which components are mounted is used. If you cannot secure enough space to install the
The printed wiring board 1.2 is divided into two parts, and these parts are mounted on the mounting frame 3 of the device using insulating support fittings 4.4a to match the shape of the mounting location, for example, by maintaining a level difference.

Further, in this case, the wiring board 1.2 was electrically connected using the connection connector 5 or the like.

[Problems to be solved by the invention]

However, the above-mentioned printed wiring board is generally made by impregnating a sheet-like glass substrate with, for example, a thermosetting phenol resin or epoxy resin to form a B-stage state (semi-cured state), and then forming a plurality of sheets of this material into a B-stage state (semi-cured state). It was manufactured by laminating layers, placing copper foil on the surface, and applying heat and pressure treatment using a laminated press. The wiring board manufactured in this way is called a so-called rigid board, and because it will break if it is forcibly bent, it can normally only be used in a flat state. Therefore, it has been completely impossible to use it three-dimensionally by bending or curving it at a constant curvature.

Therefore, as mentioned above, in devices where there is not enough space to install two printed wiring boards due to the shape of the mounting location of the printed wiring boards, as shown in Figure 1),
For example, one printed wiring board was divided into two parts, and these parts were installed by using multiple support fittings 4 and 4a of different heights to match the mounting space and securing them with screws 6. However, a large space is required to mount the printed wiring board, and as a result, many dead spaces are created, making it difficult to make electronic devices lighter, thinner, and smaller.

In addition, when installing the printed wiring board 1.2, it is necessary to divide the printed wiring board according to the shape of the mounting location, or to prepare a large number of supporting metal fittings of different heights and types. There is also a problem in that the installation work is time-consuming and labor-intensive, and as the number of parts used increases, the structure becomes more complex and manufacturing costs increase.

In particular, when connecting the divided printed wiring boards 1.2 using the connectors 5, etc., the mounting frame 3 and the support metal fittings 4.
If there are variations in the dimensional accuracy of the parts 4a, etc., the connection cannot be made smoothly, and as a result, poor contact is likely to occur, which may reduce the reliability of the equipment used.

Furthermore, it is conceivable to mold the printed wiring board into the desired shape using a molding die, but in this case, a mold for each shape is required, which is not only uneconomical but also
The molding process was time-consuming and there were problems with mass production.

In view of the above-mentioned problems, the present invention has been developed by bending or otherwise processing a specially processed printed wiring board according to the shape of the outer shell of the electronic device using the printed wiring board and the shape of the board mounting location. An object of the present invention is to provide a three-dimensional wiring circuit board in which components are mounted on a circuit board that has been subjected to bending processing.

[Means to solve the problem]

In the present invention, a thermoplastic high-viscosity polyester resin with excellent heat resistance is kneaded with an inorganic filler, a single glass fiber, and a flame retardant, and then extrusion molded to form a sheet-like insulating substrate in an amorphous state. After forming a required conductor pattern on this insulating substrate, the insulating substrate in the amorphous state is arbitrarily bent at a crystallization temperature according to the shape of the board attachment part of the electronic device, thereby forming a predetermined shape. It has excellent self-restoring properties and elasticity with a conductor pattern, and when an external force is applied to the board itself, only that part will temporarily deform within the range of the external force, but as the external force disappears, the self-returning property will be improved. In addition, during the bending process, the bending stress is reduced by making the bending part thinner or narrower than the flat part in advance. The present invention is characterized in that a three-dimensional wiring circuit board is formed.

[For production]

The present invention provides a three-dimensional wiring circuit board that has undergone the above special processing,
This circuit board can be bent into multiple stages to match the shape of the board attachment part of electronic equipment etc. that uses this circuit board, or the edges can be bent into a U-shape etc. to also serve as reinforcement of the board. ,
Since the bending and bending portions are configured in advance so that the bending stress is smaller than that of the other flat portions, the three-dimensional wiring circuit board can be easily bent or bent at a predetermined position. When installing electronic equipment etc. to the board mounting part,
It can be easily attached to match the shape of the outer shell, thereby reducing dead space and making it possible to innovate the design of the equipment.

In addition, it is possible to provide the space for the board mounting part of electronic equipment to the minimum necessary size, which allows electronic equipment to be made lighter, thinner, shorter, and more effective, and allows -2 boards to be shaped into the desired shape. By bending or curving the board, it is possible to prevent the board itself from being divided, and it is possible to efficiently and densely arrange the mounted components. Furthermore, the installation work can be done quickly and reliably without using special support metal fittings.
Furthermore, when bending the board itself, the structure is designed so that a large bending stress is not applied to the bent part compared to other parts, so there is no risk of the conductor pattern breaking during bending, etc. Smoothly and in good condition without causing any cracks.
Moreover, it is characterized by being able to be bent into a free shape.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. This will be explained using Figure 2.

First, the structure of the three-dimensional wiring circuit board used for mounting the mounted components in the present invention will be explained.

The three-dimensional wiring circuit board is made by first adding and kneading inorganic filler glass single fibers and a flame retardant to a thermoplastic, high-viscosity saturated polyester resin with excellent heat resistance, and then kneading the mixture to the required thickness (about 1.2 mm). ) is continuously extruded into a sheet to produce an insulating substrate. This insulating substrate is, for example,
This is an electrically insulating material developed by Unitika Co., Ltd., and the product name is ``Unirate'' or something similar. When this insulating substrate is extruded into a sheet, it is in an amorphous state and has high elasticity, and when heated to a crystallization temperature, it crystallizes and permanently maintains the predetermined shape. It is provided with elasticity so that it does not become flat even when an external force is applied and can self-return to a predetermined shape.

Next, using the insulating substrate formed as described above, a second
An example will be described in which a three-dimensional wiring circuit board 10 is manufactured by performing a bending process in multiple stages as shown in the figure.

First, in FIGS. 1 and 2, an adhesive sheet is placed on an insulating substrate in an amorphous state, which has been extruded into a sheet shape and formed to a predetermined thickness, at a temperature of approximately 50° C.
Temporary adhesion was carried out for about 20 minutes under pressure conditions of 1.5 liters of pressure, and then a 35 μm thick copper foil was placed on the adhesive sheet at a weight of 10 kg/a at a temperature of about 70° C. using a hot roll press. (
Lamination treatment is performed by heating and pressurizing under the following conditions. Next, an etching resist for forming a conductor pattern is printed on the copper foil and cured, followed by etching treatment using an etching liquid. Print the solder paste except for the areas that require work and harden it.

After that, the insulated substrate subjected to each of the above treatments is molded into holes for mounting electronic components and holes for mounting the board using a press mold.
At the same time, a press punching operation for adjusting the external shape is performed to produce a flat circuit board 10a. At this point,
The circuit board 10a is in a flexible amorphous state with a certain degree of flexibility and has high toughness.

Next, an embodiment in which a three-dimensional wiring circuit board 10 is attached to a board mounting portion of an electronic device using the circuit board 10a will be described with reference to FIG.

In FIG. 2, a board mounting part 1 of an electronic device (not shown) is shown.
) is an embodiment in which there is not enough space to mount two flat circuit boards 10a, and the circuit boards 10a are bent into multiple stages to be mounted.

In this case, the three-dimensional wiring circuit board 10 is formed by bending the circuit board 10a at a predetermined position at an angle close to about 900 degrees in accordance with the shape of the board mounting part 1) of the electronic device, and the insulating substrate In order to match the shape of the circuit board 10a, which is in a flat, amorphous state and has a conductor pattern (not shown) formed thereon, with the shape of the board mounting part 1), the position of the bent part 12 of the circuit board 10a is adjusted. is set in advance, and the back surface of the bent portion 12, that is, the plate surface on which the conductive pattern is not provided, is cut using a flat milling cutter or the like, for example, as shown in FIG. 7 or 8. The thickness of the plate is reduced at the position corresponding to the bent portion 12 by planing so that the thickness of the plate becomes thinner than the flat portion, or by performing arc cutting so that the top of the bent portion 12 is the thinnest portion. A thinned portion 13 is formed.

After forming the thin portion 13 at the position corresponding to the bent portion 12 of the circuit board 10a as described above, this circuit board 1
0a is placed in a heating furnace (not shown) and heated at a temperature of about 130° C. for about 30 minutes to crystallize about 15 to 20% of the amorphous insulating substrate constituting the circuit board 10a.
The toughness of the bent portion 12 of g is reduced to reduce the toughness of the circuit board 1.
Make it easier to bend 0a. In this state, the circuit board 10a
For example, when folding into the shape (multiple stages) as shown in Figure 2, first fold a pair of metal plates with excellent thermal conductivity, such as aluminum plates, that have been bent to match the shape of the board mounting part 1). The circuit board 10a is inserted into a bending jig (not shown) by bending it along the shape of the jig using the bending portion 12 thereof. At this time, since the circuit board 10a has reduced toughness, it easily conforms to the shape of the jig. After the circuit board 10a is sandwiched between the bending jigs in this way, the circuit board 10a is put into the heating furnace again and heated at a crystallization temperature of about 180° C. for about 20 minutes. When the circuit board 10a is sandwiched between the bending jigs and reheated, the circuit board 10a is cooled down to room temperature and the bending jigs are removed.The flat circuit board 1a has almost no toughness. The three-dimensional wiring circuit board is bent into the shape shown in Figure 2.
O can be formed. The three-dimensional wiring circuit board 10 formed as described above changes from a flexible, non-crystalline insulating substrate (circuit board 10a) to a rigid, completely crystalline state. As a result, the three-dimensional wiring circuit board lO
Even if an external force is applied to, for example, flattening the thin wall portion 13, as well as the flat portion of the plate, the flat portion or the bent portion 12 will return to its original state when this external force disappears. It was confirmed that there was no change in the three-dimensional wiring circuit board IO itself.

The three-dimensional wiring board 10 bent as described above has
The required mounting components 18 for driving the electronic device are each mounted at predetermined positions on the conductor pattern, and mounted on the board mounting part 1) of the electronic device, and the locking parts 18 provided in advance on the board mounting part 1) are mounted. The mounting hole 16 (see FIG. 6) formed in the mounting leg 15 of the three-dimensional wiring circuit board IO is fitted into the means 14 to attach the three-dimensional wiring circuit board IO to the board mounting part 1). At this time, the locking means 14 is, for example, as shown in FIG. 6, a pair of locking pieces a and b divided into two are integrally provided on the board mounting part li, and the three-dimensional wiring circuit board IO is When locking the mounting leg part 15, fit the mounting hole part 16 into the upper part of the pair of locking pieces a and b, and press the mounting leg part 15 toward the board mounting part 1). The locking pieces a, b are pressed against each other toward the gap between them, and their tips become narrower, so that the mounting holes 16 are fitted to the bases of the locking pieces a, b. The mounting leg portion 15 can be fixed and held on the board mounting portion 1) through the insulating member 17 in a state in which the mounting leg portion 15 is fixed to the hook portion of the board mounting portion 1). By using the above-mentioned locking means 14, the three-dimensional wiring circuit board IO bent into multiple stages can be attached to the board mounting part 1) of the board mounting part II without adversely affecting the curved shape. It is very convenient because it can be installed in one operation by making effective use of dead space.

In FIG. 2, reference numeral 19 indicates a space 19a of the three-dimensional wiring circuit board lO which is bent into multiple stages and attached to the board mounting part 1).
For example, when placed on the board mounting part II by effectively utilizing the
This is the power supply section of electronic equipment.

Next, a second embodiment of the present invention will be described with reference to FIG.

Fig. 3 shows an example in which a circuit board 10a is bent into a U-shape due to the shape of the board mounting part 1)a of an electronic device. As shown in FIG. 9, a flat, non-crystalline circuit board lOb on which a conductive pattern (not shown) is formed is bent into a U-shape at a position corresponding to the curved portion 12a.
Arc-shaped notches 13a are formed at both widthwise ends of the circuit board 10b to facilitate bending. Note that the arc-shaped notch 13a may be provided at the time when the insulating substrate is manufactured before the circuit board lOb is provided.

As described above, the circuit board 1. Bent part 12a of Ob
After forming the arc-shaped notch 13a at the position corresponding to 1
, the second circuit board 10b is placed in a heating furnace (not shown), and heated for about 1
Heating is performed at a temperature of 60° C. for about 30 minutes to substantially crystallize the circuit board 101) which is in an amorphous state, thereby reducing its toughness and making it easier to bend the circuit board 12a. In this state, the mounting components 18 for driving the electronic device are mounted at respective predetermined conductor pattern positions. As shown in FIG.
) For example, when mounting the battery housing case 20 protruding from the center of the circuit board 10b, the circuit board 10b is placed in a U-shape so that the mounted components 18 face each other around the curved part 12a of the circuit board lOb. to curve it. In this case, the toughness of the circuit board 10b is reduced, and an arc-shaped notch 13a is formed at the position where the circuit board 10b is curved.
Since this part is formed in advance and has a smaller area than other flat parts, that is, it has a narrow width,
It can be curved smoothly. In this state, a curved molding jig (not shown) with a preset curvature for forming the curved part 12a is clamped onto the curved portion of the circuit board 10b, and a heater (not shown) built into this molding jig is attached. Electricity is applied to heat the forming jig, and the curved portion 12a of the circuit board 10a is locally heated at a crystallization temperature of about 180° C. for a certain period of time. When the heating operation is completed and the circuit board is cooled down to room temperature and the forming jig is removed, the curved portion of the circuit board 10b has almost no toughness, and the tip is bent to a predetermined position as shown in FIG. It is possible to form a U-shaped three-dimensional wiring circuit board 10 that is curved. This U
Although the flat portion of the three-dimensional wiring circuit board lO having a letter shape is not completely crystallized except for the curved portion 12a, since the curved portion 12a is crystallized, when an external force is applied to the curved portion 12a, - Although its curvature changes over time, the curved portion 12a immediately returns to its original state as the external force disappears, and does not have any adverse effect on the overall shape of the three-dimensional wiring circuit board IO formed in a U-shape. As mentioned above,
As shown in FIG. 3, the three-dimensional wiring circuit board 10 having a curved tip is fixed to the base of the board mounting portion 1)a by using a set screw 21 or the like while straddling the housing casing 20. As a result,
The U-shaped three-dimensional wiring circuit board 10 is simply mounted on its free end side, and the dead space of the board mounting part 1)a can be effectively utilized without using any special support member or the like for the board mounting part 1)a. It can be easily installed. Also, set screw 21
When attaching the three-dimensional wiring circuit board 1O properly, as shown in FIG. The board IO may be fixedly attached to the board attachment part 1)a. In this case, since the bent portion +5a has a double structure, it has the advantage that its mechanical strength can be increased to ensure fastening.

Furthermore, FIG. 4 shows the embodiment of the present invention shown in FIG. 3, in which the end of the circuit board 10e is bent into an L shape to form a recess 24 on the lower surface of the three-dimensional wiring circuit board IO. Then, the mounting legs 22 bent in the above-mentioned L-shape located on both sides of this recessed portion 24 are mounted to the board mounting portion lIc using the locking means 14 (Please note that this three-dimensional wiring circuit board lO is Due to the presence of the legs 22, it becomes possible to strengthen the mechanical strength and attach the protruding member 23 of the board mounting part lie to the board mounting part lie while housed in the recess 24. The depth dimension can be set according to the shape of the protruding member 23 of the mounting part lie, and the bending work of the circuit board 10c when forming this recessed part 24 is performed in accordance with the above-mentioned steps 1 and 1) 12. Since this can be carried out using the same work steps as in the example, the explanation thereof will be omitted. in this case,
Needless to say, a separate jig for forming the mounting leg portion 22 is required.

Further, FIG. 5(A) shows an embodiment in which a three-dimensional wiring circuit board IO and a normal hard board 25 are combined, and in this case,
A predetermined conductor pattern is formed on the front and back surfaces of an amorphous insulating substrate 10d, and this is bent into, for example, an L shape at a crystallization temperature to form a circuit board lOd.
On the flat surface of is a hard substrate 2 with a conductor pattern on the back side.
5 through an adhesive sheet 26, and then, as shown in FIG. The conductor patterns of the substrates 10d and 25 are connected at necessary locations. In this state, the mounting component 18 is mounted at a predetermined position on the upper surface of the hard substrate 24 having no conductor pattern. In this case, since there is only a conductor pattern for connecting the mounted component and no conductive pattern for wiring at all in the mounting area of the mounted component 18, the mounted component 18 is not obstructed by the conductive pattern for wiring (high It has the advantage of being able to be mounted in a dense state.

In the second embodiment, instead of providing the arcuate notch 13a at the end of the circuit board 10b in the radial direction, the circuit board 1
Instead of providing a horizontally elongated hole along the curve/white direction of 0b, or providing the notch 13a or the elongated hole, the inner surface of the curved portion 12a is formed as shown in FIGS. 7 and 8. The present invention can also be achieved even if the bending stress of the curved portion 12a is reduced by forming the curved portion 12a thinly.

〔Effect of the invention〕

Since the three-dimensional wiring circuit board of the present invention is configured as described above, it can be mounted by performing bending processing to match the shape of the board mounting part of electronic equipment, thereby saving the put space of the board mounting part. It can be installed with significantly reduced size. This means that even if the board mounting part has protrusions or recesses due to the structure of the device, it can be mounted three-dimensionally by bending the circuit board to match the outer shell shape of these parts. Therefore, the board mounting part can be used in the same way as when installing a flat printed wiring board, as in the conventional case.
Since it can be downsized without requiring more installation space than necessary, it is possible to promote miniaturization of electronic devices.

Further, when bending a three-dimensional wiring circuit board, the bending section is
Since the bending stress is smaller than that of other flat parts, the bending process can be performed smoothly and favorably without damaging the conductor pattern.

[Brief explanation of drawings]

No. 1II is a process 1 schematically showing the manufacturing process of the three-dimensional electric wire circuit board of the present invention, and No. 251 is a three-dimensional wiring circuit 1Nl of the present invention.
An explanatory diagram for explaining the mounting state of Il&complex, 3rd part is a diagram showing another mounting state of the three-dimensional wiring circuit board of the present invention, and Fig. 4 is a diagram showing still another mounting state of the present invention. Ill! 1
FIG. 5(A) is an explanatory diagram for explaining the state in which the three-dimensional wiring circuit board of the present invention and a normal wiring board are used in combination, and FIG. ), Fig. 6 is an enlarged sectional view of the P part of Fig. 2, Fig. 7 is an enlarged sectional view of the X part of Fig. 2, and Fig. 8 is another implementation of Fig. 7. FIG. 9 is a cross-sectional view of main parts showing an example, FIG. 9 is a plan view expanded from the Z arrow view part of FIG. 3, and FIG. FIG. 1 is an explanatory diagram for explaining the mounting state of a conventional printed wiring board. 0. Three-dimensional wiring circuit board, 0a-10d. Circuit board, 1-1) c. Board mounting portion, 12. Bent portion, 2a. Curved portion, 13. Thin wall portion, 3a. Notch portion, 14. Locking means. , 5.22・Mounting legs

Claims (4)

[Claims] (1) Thermoplastic high-viscosity polyester resin is filled with glass single fibers, inorganic fillers, and fillers such as flame retardants, and this is extruded to form a sheet-like amorphous insulating substrate. A circuit board is formed by providing a predetermined conductor pattern on the board, and this circuit board is bent or curved together with the mounting legs at a crystallization temperature into a shape corresponding to the board mounting part to form a three-dimensional wiring circuit board. 1. A three-dimensional wiring circuit board, characterized in that the three-dimensional wiring circuit board is mounted with necessary mounting components and is attached to a board mounting part via the mounting legs. (2) The three-dimensional wiring circuit board according to claim 1, wherein the bent and curved portions of the circuit board are formed so that bending stress is smaller than other flat portions. (3) The three-dimensional wiring circuit board according to claim 2, wherein the bent portion of the circuit board is formed to be thinner than other flat portions. (4) The three-dimensional wiring according to claim 2, characterized in that the curved portion of the circuit board is formed with arc-shaped or rectangular notches at both ends thereof in the width direction toward the center in the width direction. circuit board.