JPH0582918A - Flexible printed board - Google Patents

Abstract

PURPOSE:To make it possible to mount electronic components efficiently with no interference and to prevent disconnection of the lead wire of electronic component at the time of folding or soldering. CONSTITUTION:Electronic components 6 are mounted at the main mounting part 7 of one flexible printed board body 4 wherein the elongated main mounting part 7 is arranged in parallel with sub-mounting parts 8a, 8b and respective mounting parts 7, 8a, 8b are made continuous, on one sides thereof, through joints 9a, 9b and a signal cable 5 is connected with the sub-mounting sections 8a, 8b. The flexible printed board body 4 is formed, in cubic, with the joints 9a, 9b as side faces and the mounting parts 7, 8a, 8b as opposing faces. Since the joints 9a, 9b are formed narrow, bending stress is not exerted on the electronic components to be mounted and since the adjacent mounting parts 7, 8a, 8b are arranged oppositely, the electronic components can be mounted efficiently with no interference.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible printed circuit board which can be bent easily and can be mounted on a relatively elongated insertion portion.

[0002]

2. Description of the Related Art As is well known, a flexible printed circuit board is comparatively thin and has excellent flexibility, and can be efficiently housed in a narrow space inside a device. Therefore, it is used in many electric devices. ing.

For example, in an image pickup section of an electronic endoscope in which electronic components having rigidity such as a solid-state image pickup element, an IC, and a condenser are incorporated, there is a tendency toward smaller size in order to meet the demand for a smaller diameter of the insertion section and the tip section. In order to save space on the mounting board, the flexible printed board is used, and the flexible printed board is three-dimensionally bent while the electronic component is mounted and mounted on the tip of the insertion portion.

Conventionally, many flexible printed boards of this type have a simple shape such as a rectangle. Therefore, when this flexible printed board is bent while being mounted, an electronic component which is a rigid body disposed in the vicinity of the bent portion. The bending stress acts between the lead wire and the substrate, and the lead wire may be broken.

To cope with this, for example, the actual Kaihei 1-1
Japanese Patent No. 54684 discloses a technique for preventing bending stress from spreading to a lead wire of an electronic component at the time of bending by providing a slit, a notch, and a small hole in a bent portion of a flexible printed circuit board. ing.

[0006]

By the way, in a flexible printed circuit board mounted on a narrow insertion portion such as an image pickup portion of an electronic endoscope, a plurality of mounting portions for mounting electronic components are made adjacent to each other via a bending portion. When assembled three-dimensionally, the components mounted on the respective mounting portions are likely to interfere with each other, leading to a reduction in mounting efficiency.

Further, when the adjacent mounting portions are close to each other, in the soldering work, the heat of the solder is transferred to the electronic component of the other mounting portion, and the lead wire is likely to be broken.

The present invention has been made in view of the above circumstances, and it is possible to efficiently mount electronic components on the respective mounting portions without interfering with each other, and in addition, at the time of bending and soldering. It is an object of the present invention to provide a flexible printed board in which lead wires of parts are not broken.

[0009]

In order to achieve the above object, a flexible printed circuit board according to the present invention comprises a plurality of elongated mounting portions and a narrow connecting portion for connecting the mounting portions adjacent to each other. In the flexible printed circuit board body, the mounting portions adjacent to each other are disposed to face each other, and the connection portions are disposed on the side surfaces, so that the flexible printed circuit board body can be inserted into the elongated insertion portion.

[0010]

[Operation] In the above configuration, since a plurality of elongated mounting parts are bent through the narrow connecting parts, the bending stress at the time of bending may lead to lead wires of electronic components mounted on each mounting part. It does not spread, and it becomes more difficult for the heat of the solder to be transferred to the other mounting portion.

Further, since the mounting portions adjacent to each other are disposed so as to face each other and the connecting portions are disposed on the side surfaces so that the mounting portions can be inserted into the elongated insertion portions, the electronic parts can be mounted on the mounting portions. Can be efficiently implemented without interference.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 5 show a first embodiment of the present invention,
1 is a development view of the flexible printed circuit board, FIG. 2 is a perspective view showing the procedure for assembling the flexible printed circuit board, and FIG.
Is a perspective view of the imaging unit, FIG. 4 is a side view of the imaging unit, and FIG. 5 is a sectional view of the tip of the endoscope insertion unit.

Reference numeral 1 in the drawing denotes a relatively thin and small-diameter tip of the insertion portion of the electronic endoscope.
The imaging unit 2 is attached to the. The image pickup unit 2 includes a solid-state image pickup device 3 such as a CCD, a flexible printed circuit board body 4, a signal cable 5 and the like.

The flexible printed circuit board body 4 comprises
An elongated main mounting portion 7 for mounting an electronic component 6 such as an IC and a capacitor which is electrically connected to the solid-state imaging device 3 and two sub-mounting portions 8a, 8 arranged in parallel with the main mounting portion 7.
b, and the narrow connecting portions 9a and 9b for connecting one ends of the respective mounting portions 7, 8a and 8b.

A cable land 10 for connecting the signal cable 6 is formed on each of the sub-mounting portions 8a and 8b.

An electrode 11 is formed on the back surface of the main mounting portion 7 and is electrically connected to the electronic component 6 mounted on the front surface.
Electrodes (bumps) 12 that are electrically connected to the signal cable 5 connected to the front surface are formed on the back surfaces of the sub-mounting portions 8a and 8b.

As shown in FIG. 3, in the three-dimensionally assembled flexible printed circuit board body 4, the main mounting portion 7 and the sub-mounting portion 8a are arranged opposite to each other via a connecting portion 9a, and Another sub-mounting portion 8b is arranged in a superposed state on the back surface of the main mounting portion 7, and the electrode 11 of the main mounting portion 7 and the electrode 12 of the sub-mounting portion 8b are brought into contact with each other so that the solid-state imaging device 3 described above.
And the signal cable 5 are electrically connected. Further, the connecting portions 9a and 9b are arranged on the side surfaces so as to face each other.

(Operation) Next, the operation of the embodiment having the above construction will be described.

First, the electronic parts 6, the signal cable 5 and the like are soldered to the mounting portions 7, 8a, 8b of the flexible printed circuit board body 4 in the expanded state in a predetermined manner (state of FIG. 1). Since the distances between the respective mounting portions 7, 8a, 8b are arranged at positions relatively distant via the connecting portions 9a, 9b, the heat of the solder is not applied to the other mounting portions 7, 8a, 9b. 8
It is difficult to transmit to the side a or 8b, and therefore, the lead wires of the electronic component 6 are not accidentally broken.

Next, the main mounting portion 7 of the flexible printed circuit board main body 4 and the sub-mounting portion 8a adjacent to the main mounting portion 7 are bent at the connecting portion of the connecting portion 9a as a boundary, and are arranged to face each other. Another sub-mounting portion 8b adjacent to the sub-mounting portion 8a is superposed on the back surface of the main mounting portion 7. As a result, the electrode 11 of the main mounting portion 7 and the electrode 1 of the sub mounting portion 8b are
2 are in contact with each other, and both the connecting portions 9a and 9b are arranged so as to face the side surface.

At this time, since the mounting portions 7, 8a, 8b are continuously connected via the narrow connecting portions 9a, 9b, the unreasonable force at the time of bending is connected to the main mounting portion 7. It is not applied to the lead wire of the electronic component 6, etc.

Further, the main mounting portion 7 and the sub mounting portion 8a are disposed so as to face each other, and the back surface of the sub mounting portion 8b is superposed on the back surface of the main mounting portion 7a. , The electronic parts 6 mounted on the mounting parts 7, 8a, 8b are less likely to interfere with each other, and therefore, the mounting parts 7, 8 are mounted.
The mounting efficiency of the electronic component 6 or the like for a and 8b is improved.
After that, the solid-state image pickup device 3 is connected to the tip of the flexible printed circuit board body 4, the solid-state image pickup device 3 and the signal cable 5 are brought into conduction, and the assembly of the image pickup unit 2 is completed (FIG. 3, FIG. 4).

Then, the image pickup section 2 assembled in a predetermined manner is mounted on the tip 1 of the insertion section of the electronic endoscope.

(Second Embodiment) FIGS. 6 and 7 show a second embodiment of the present invention. FIG. 6 is a development view of a flexible printed circuit board, and FIG. 7 is a side view of an image pickup section.

In the flexible printed circuit board body 21 shown in this embodiment, the mounting portions 7, 8a, 8b are connected to the connecting portion 9a,
They are arranged in series via 9b, and the operational effects are the same as in the first embodiment.

(Third Embodiment) FIGS. 8 and 9 show a third embodiment of the present invention. FIG. 8 is a development view of a flexible printed circuit board, and FIG. 9 is a side view of an image pickup section.

In this embodiment, a TAB (Tape Auto Made Bonding) tape is used as the flexible printed circuit board body 26, a cable land 27 is formed at the tip of the main mounting portion 7, and the tip of the main mounting portion 7 is assembled. It is bent to connect the bumps 3b of the CCD chip 3a, and the operational effects are the same as those of the first embodiment.

Reference numeral 28 in the drawing is a cover glass, 2
9 is a sealing resin.

[0030]

As described above, according to the present invention,
Electronic components can be efficiently mounted on each mounting unit without interfering with each other. Furthermore, the bending stress at the time of three-dimensional molding does not spread to the lead wire of the electronic component, and the heat of the solder is hard to be transferred to other mounting parts, so that the lead wire of the electronic component is not broken. The effect that it can be prevented is exhibited.

[Brief description of drawings]

FIG. 1 is a development view of a flexible printed circuit board according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing an assembly procedure of the flexible printed circuit board.

FIG. 3 is a perspective view of the imaging unit.

FIG. 4 is a side view of the imaging unit.

FIG. 5 is a sectional view of the distal end of the endoscope insertion portion.

FIG. 6 is a development view of a flexible printed circuit board according to a second embodiment of the present invention.

FIG. 7 is a side view of the imaging unit.

FIG. 8 is a development view of a flexible printed circuit board according to a third embodiment of the present invention.

FIG. 9 is a side view of the imaging unit.

[Explanation of symbols]

 1 ... Insertion part 4, 21, 26 ... Flexible printed circuit board main body 7 ... Mounting part 9a, 9b ... Connection part

Claims (1)

[Claims] 1. A flexible printed circuit board main body comprising a plurality of elongated mounting portions and a narrow connecting portion for connecting between the mounting portions adjacent to each other, and the mounting portions adjacent to each other are arranged to face each other. Also, a flexible printed circuit board is characterized in that the connecting portion is arranged on a side surface so that the connecting portion can be inserted into an elongated insertion portion.