JPH0210790A - Flexible printed wiring board and parts mounting method - Google Patents

Abstract

PURPOSE:To make it suitable for assembling in thin electronic apparatus by meandering a wiring leading to a parts mounting part such that it surrounds the periphery of the mounting part, and forming an intermittent cut part in a printed board at the side of meandering wiring. CONSTITUTION:The wiring 6 to connect with a minimold part 1 which is mounted in a device hole 3 is so meandered and arranged as to surround the periphery of a hole 3, and a perforated intermittent cut part is formed at the side of the meandering wiring. After mounting the part to a printed board, and before assembling it to an apparatus, the connected part which was left at the cut part 4 is separated completely. By separating it, the part is put in a floating condition that it can shift relatively freely, so the part 1 comes out to the surface passing through the hole 3. Hereby, a meandering wiring part 7 opens in bellows shape drawing slow inclination, whereby all the parts can be collected onto one face without causing great distortion at the wiring board, and mounting density does not lower.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a flexible printed wiring board suitable for mounting and assembling parts of thin electronic devices such as card calculators and memory cards, and a method for mounting parts. be.

(Prior Art) Due to its excellent flexibility, flexible printed wiring boards are often used for wiring of movable parts of various electronic devices or for wiring on multiple surfaces in micro spaces of small devices such as cameras.

In the former case, it has almost the same function and form as a flat cable, and in the latter case, it is originally used as a wiring board. In cases similar to the latter, when thickness constraints become even stronger, surface mount components are usually used, but in some cases, wiring boards are used to reduce the thickness of the wiring board itself. The method used is to make a hole (device hole) that is slightly larger than the outer circumference of the component to be mounted on the device and connect it to the wiring board on the back side.

Conventionally, in such cases, most components are first mounted on the front side, and those that need to be connected on the back side through device holes are then manually mounted. In this case, manual soldering not only requires more man-hours, but also increases the number of steps, complicates process control, and tends to cause problems in terms of quality control.

In addition, when the component mounting wiring board obtained in this way is assembled, the connection part protrudes on the back side of the board using device holes, so a measure to accommodate it is required, and if there are strong restrictions on the thickness, this is also a big problem. Furthermore, if components that use device holes and components that do not are mounted at the same time, most of the components that use device holes are on the back side of the wiring board, so it may be difficult to mount parts that use device holes or other components that do not have a limited gap, such as a card calculator or memory card. In addition to causing large distortions on the wiring board, it is necessary to provide a fairly large non-mounting area between the part where components using device holes are mounted and the part where components that do not use device holes are mounted. However, there was a drawback that high-density mounting was not possible.

(Problems to be Solved by the Invention) In view of these problems in mounting components on flexible printed wiring boards, the present invention aims to connect components that use device holes at the same time on one side (front surface) when mounting components. In addition, it is possible to simultaneously mount components that use device holes and those that do not, without drastically lowering the packaging density. Also, during assembly, measures can be taken to accommodate the connecting parts relatively easily, and components can be mounted easily. The object of the present invention is to provide a flexible printed wiring board that does not cause distortion in the wiring board even when the wiring board is installed in a limited gap, and a method for mounting the same.

(Means for Solving the Problems) That is, the present invention arranges wiring connected to a component mounting portion of a flexible printed wiring board based on a plastic film in a meandering manner so as to surround the outer periphery of the component mounting portion. , a flexible printed wiring board characterized in that intermittent cutting parts are formed in the printed wiring board base material on the side of the meandering wiring, and components are arranged in the component mounting part, and electrical connections are made to the printed wiring board. This component mounting method is characterized by completely cutting off the intermittent cut portions of the printed wiring board base material after connecting the component to the printed wiring board base material, and leaving the component in a floating state.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A flexible printed wiring board according to an embodiment of the present invention and a component mounting method using the same will be described in detail below with reference to the drawings.

FIG. 1 shows an example of a wiring board according to the present invention, and is a plan view of a state in which components are mounted. Further, FIG. 2 is a diagram showing how parts are mounted on a wiring board according to the present invention and assembled into a device.

As shown in FIG. 1, the wiring (6) for electrically connecting the mini-mold component (1) mounted in the device hole (3) is connected to the component mounting part, in this example, the device hole (3). ) are arranged in a meandering manner so as to surround the outer periphery of the wiring, and intermittent cut portions (4) such as perforations are formed in the printed wiring board base material on the side of each meandering wiring. . The cutting section (4) is not completely cut off as indicated by the broken line, but is left partially connected to the extent that it can withstand component mounting.By doing this, all components can be mounted at the same time. becomes possible.

The method for forming the cut portion (4), which is the key point of the present invention, is a cutting tool (Bikku) in which a ``steel'' blade is fitted into a temporary piece of wood, which is used as a simple punching method for flexible printed wiring boards. There is a method in which an intermediate workpiece of the circuit board is sandwiched between the mold and the backup material and compressed using a flat plate press. If precision in cutting position is required, take measures such as replacing the wooden board with a metal one. To leave the part connected to the cutting part (4), you can crush the part of the blade that you want to leave as described above, or make a half cut with the size of this "crushed" part, etc. It is possible to adjust the strength of

Next, a method for mounting components on the flexible printed wiring board thus obtained will be described. First, as shown in the figure, a chip component (2) is attached to the soldered part (5) on the surface of the wiring board, and a slightly larger mini-mold component (1) is attached.
), as shown in Figure 2(a), the component body is located on the back side of the wiring board, the lead wire 0[D is set on the front side, and the soldering process is performed to separate different types of components. can be implemented simultaneously.

Next, before assembling the obtained component-mounted wiring board into a device, the connected portion left at the cut section (4) is completely separated. Figure 2 (b) shows how it is assembled into a device. , As the cutting part (4) is completely separated, the mini-mold part (1) is in a floating state where it can move relatively freely, so the part (
1) passes through the device hole (3) and exits to the front side of the wiring board. As a result, the meandering wiring section (7), which has been cut and is in a free state, opens in a bellows shape with a gentle slope, and all the components can be moved to one side of the wiring board without causing any major distortion to the wiring board. It can be seen that the parts can be placed in any desired position, such as being able to move them to the same surface, and that the packaging density has not decreased much.

Figure 2(b) shows the state in which the flexible printed wiring board with components mounted in this way is housed in the frame θ1) of the device, and the frame (11) and the wiring board are bonded and fixed with zero adhesive. It shows.

In the example shown in Fig. 1, the component mounting area is a device hole, but it is not necessarily necessary to use a device hole. There is no problem with a method in which the mounted parts can be moved freely by forming a part and completely separating the parts after mounting them, and the same effect as the method of providing a device hole can be obtained. It will be done.

(Effect of the invention) By using the flexible printed wiring board and its mounting method according to the present invention, components that require device holes, etc., which had to be mounted later using conventional methods, can be mounted simultaneously with other components. This makes it possible to significantly reduce man-hours and improve connection reliability.

Furthermore, when compared to a board in which only device holes are formed without using the present invention and all components are mounted at the same time, the wiring board using the present invention has components protruding from one side (the back side in the example). Since there are no holes, the assembly is easy, and there is no distortion in the wiring board and almost no reduction in the mounting density of components, making it particularly suitable for assembling thin electronic crosspieces.

Figure 1

[Brief explanation of the drawing]

FIG. 1 shows an example of a wiring board according to the present invention, and is a plan view of a state in which components are mounted. In addition, Fig. 2 is a diagram showing how parts are mounted on a wiring board according to the present invention and assembled into a device. FIG. 3 is a side view of the device when it is housed in the frame of the device. Figure 2

Claims (2)

[Claims] (1) The wiring connected to the component mounting section of a flexible printed wiring board based on a plastic film is arranged in a meandering manner so as to surround the outer periphery of the component mounting section,
A flexible printed wiring board characterized in that intermittent cut portions are formed in a printed wiring board base material beside meandering wiring. (2) After placing the components on the component mounting portion of the flexible printed wiring board according to claim (1) and electrically connecting them to the printed wiring board, the intermittent cut portions of the printed wiring board base material are completely removed. A component mounting method characterized by separating the components and leaving them in a floating state.