JP3148297B2 - Flexible printed circuit board - Google Patents

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 easily bent 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 relatively thin and excellent in flexibility, and can be efficiently accommodated in a narrow space in a device. ing.

For example, in an image pickup section of an electronic endoscope in which rigid electronic parts such as a solid-state image pickup device, an IC, and a capacitor are incorporated, the size of the insert section and the tip section has been reduced in order to meet the demand for a smaller diameter. In order to save space on the mounting board, the above-mentioned flexible printed board is used, and the flexible printed board is three-dimensionally bent while the electronic components are mounted, and is mounted on the distal end of the insertion portion.

Conventionally, this type of flexible printed circuit board is often of a simple shape such as a rectangle. Therefore, when this flexible printed circuit board is bent in a mounted state, it is a rigid electronic component disposed near a bent portion. Bending stress acts between the lead wire and the substrate, and the lead wire may be broken.

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

[0006]

In a flexible printed circuit board to be mounted on a narrow insertion section such as an imaging section of an electronic endoscope, a plurality of mounting sections for mounting electronic components are adjacent to each other via a bent section. When the components are mounted three-dimensionally, the components mounted on the respective mounting portions easily interfere with each other, resulting in a reduction in mounting efficiency.

In addition, when the adjacent mounting portions are close to each other, in the soldering operation, inconveniences such as the heat of the solder being transmitted to the electronic component of the other mounting portion and the break of the lead wire are likely to occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and allows an electronic component to be efficiently mounted on each mounting portion without interfering with each other. An object of the present invention is to provide a flexible printed circuit board in which lead wires of components are not broken.

A flexible substrate according to the present invention has a first surface on which electronic components are mounted and a second surface corresponding to a back surface of the first surface.
And a flexible printed circuit board having a mounting portion for mounting an electronic component on the first surface, and at least one having a first electrode electrically connected to the electronic component on the second surface. A main mounting portion, a cable land for soldering a signal cable on the second surface, and at least one auxiliary having a second electrode electrically connected to the cable land on the first surface. The mounting portion, the second surface of the main mounting portion and the first surface of the sub-mounting portion overlap each other, the main mounting portion is deformable so that the first electrode and the second electrode are in contact with each other. And a connecting portion connected between the sub-mounting portion and the sub-mounting portion.

[0010]

[Action] In the above structure, since the so bent through freely <br/> connecting portion deforms the mounting portion of the multiple lead wires of electronic components bending stress during the bending is mounted on the mounting portion such And the heat of the solder is less likely to be transmitted to the other mounting portion.

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

[0012]

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

FIGS. 1 to 5 show a first embodiment of the present invention.
FIG. 1 is an exploded view of the flexible printed circuit board, FIG. 2 is a perspective view showing an assembly procedure of the flexible printed circuit board, and FIG.
4 is a perspective view of the imaging unit, FIG. 4 is a side view of the imaging unit, and FIG. 5 is a cross-sectional view of the end of the endoscope insertion unit.

Reference numeral 1 in the drawing denotes a relatively elongated and small-diameter insertion portion tip of the electronic endoscope.
The imaging unit 2 is mounted on the camera. The imaging unit 2 includes a solid-state imaging device 3 such as a CCD, a flexible printed board main body 4, a signal cable 5, and the like.

The flexible printed circuit board body 4 includes:
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 and 8 disposed in parallel to the main mounting portion 7.
b, and narrow connecting portions 9a and 9b connecting one end between the mounting portions 7, 8a and 8b.

A cable land 10 for connecting the signal cable 5 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 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 flexible printed board body 4 assembled three-dimensionally, the main mounting portion 7 and the sub-mounting portion 8a are arranged to face each other via a connecting portion 9a. Another sub-mounting portion 8b is disposed on the back surface of the main mounting portion 7 in an overlapping state, and the electrodes 11 of the main mounting portion 7 and the electrodes 12 of the sub-mounting portion 8b are brought into contact with each other, and
And the signal cable 5 are in a conductive state. Further, the connection portions 9a and 9b are disposed to face each other on the side surface.

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

First, the electronic component 6, the signal cable 5, and the like are soldered to the mounting portions 7, 8a, 8b of the expanded flexible printed circuit board main body 4 in a predetermined state (the state of FIG. 1). Since the distances between the mounting portions 7, 8a, 8b are arranged at relatively distant positions via the connecting portions 9a, 9b, the heat of the solder reduces the heat of the other mounting portions 7, 8 at the time of soldering. 8
It is difficult to transmit to the a or 8b side, so that the lead wire or the like of the electronic component 6 is not accidentally disconnected.

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 arranged opposite to each other by bending the connection portion 9a as a boundary. The other sub-mounting portion 8b adjacent to the sub-mounting portion 8a is superimposed 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
2 are brought into contact with each other, and the two connecting portions 9a and 9b are disposed opposite to each other on the side surface.

At this time, since the mounting portions 7, 8a, 8b are continuously provided via the narrow connecting portions 9a, 9b, an excessive force at the time of bending is connected to the main mounting portion 7. Is not applied to the lead wires of the electronic component 6.

Further, the main mounting portion 7 and the sub mounting portion 8a are disposed to face each other, and the back surface of the sub mounting portion 8b is superimposed on the back surface of the main mounting portion 7a. The electronic components 6 mounted on the mounting portions 7, 8a, 8b are unlikely to interfere with each other.
The mounting efficiency of the electronic component 6 and the like with respect to a and 8b is improved.
Thereafter, the solid-state imaging device 3 is connected to the front end of the flexible printed circuit board main body 4, and the solid-state imaging device 3 and the signal cable 5 are brought into a conductive state to complete the assembly of the imaging unit 2 (FIGS. 3 and 3). 4).

Then, the imaging section 2 assembled in a predetermined manner is mounted on the distal end 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 portions 9a, 9a.
The components are arranged in series via the components 9b, and the operation and effect are the same as those of the first embodiment.

(Third Embodiment) FIGS. 8 and 9 show a third embodiment of the present invention. FIG. 8 is a developed 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 main 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 at the time of assembly. It is bent to connect the bump 3b of the CCD chip 3a, and the operation and effect are the same as in the first embodiment.

Reference numeral 28 in the drawing denotes 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 section without interfering with each other. Furthermore, the bending stress during three-dimensional molding does not spread to the lead wires of the electronic component, and the heat of the solder is difficult to be transmitted to other mounting parts. Therefore, disconnection of the lead wire of the electronic component can be prevented beforehand. The effects such as prevention can be achieved.

[Brief description of the 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 a procedure of assembling 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 cross-sectional view of the distal end of the insertion section of the endoscope.

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]

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

Claims (1)

(57) [Claims] A first surface on which an electronic component is mounted;
Flexible surface having a second surface corresponding to the back surface of the
The lint board has a mounting portion for mounting an electronic component on the first surface.
And the first surface is electrically connected to the electronic component on the second surface.
At least one main mounting portion having electrodes, and a cable for soldering a signal cable to the second surface.
Cable land, and the first surface has the cable
A small electrode having a second electrode in electrical communication with the cable land.
At least one submount, a second surface of the main mount , and a second surface of the submount.
The first electrode and the second electrode are overlapped on one surface.
The main mounting part and the sub mounting part, which are deformable to be in contact with each other.
A flexible printed circuit board characterized by having a a continuously provided connection portion between.