JPS6229083A - Flexible circuit board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a flexible substrate, and more particularly to a connection structure by thermocompression bonding between a conductive pattern of a flexible substrate and an electrode pattern of an object to be connected.

(Prior Art) For example, a flexible substrate used in a liquid crystal display device and for applying voltage to a plurality of segment electrodes constituting liquid crystal picture elements in a liquid crystal panel is as shown in FIG.
A plurality of conductive patterns 2 made of, for example, copper foil are arranged in parallel in a flat coverlay 1 that is elastic and insulating.

This conductive pattern 2 is connected by thermocompression bonding using, for example, solder, a conductive film, etc. to the electrode pattern led out from each segment electrode to the edge of the liquid crystal panel. It is composed of a conductive line 3 and a power supply line 4 connected to the segment electrode connected to the conductive line 3 and all other pairs of electrodes.

The conductive line 3 is formed so that the line width of the connecting portion 3b connected to the electrode pattern is thicker than the line portion 3a for connection, and the power line 4 is formed so that the line width of the connecting portion 3b connected to the electrode pattern is thicker than the line portion 3a. The line width is formed thick for connection, and the line portion 4 from this connection portion 4b
The line width of a is made wider than the line portion 3a of the conductive line 3 because of its large current capacity.

[Problem that the invention seeks to solve]

In the conventional flexible substrate, when the connecting portions 3b and 4b of the conductive pattern 2 are thermocompression bonded to the electrode pattern using, for example, solder, the heat applied to the connecting portions 3b and 4b is transferred to the line portions 3a and 4a, respectively. However, the power supply line 4 is connected to the line portion 3a of the conductive line 3.
Since the line width of the line part 4a is thick and has good thermal conductivity, the temperature of the connection part 4b of the power line 4 does not rise, and the adhesion with the solder is poor, resulting in failure of the connection between the power line 4 and the electrode pattern. It was reliable and the yield was poor.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a flexible substrate in which a conductive pattern can be reliably connected to a power line.

(Means for Solving the Problems)' The present invention provides a flexible substrate 21 having a conductive pattern 23 connected to an electrode pattern 15 of an object to be connected by thermocompression bonding.
a conductive line 25 in which the line width of the connecting portion 25b connected to the electrode pattern 15 is made thicker than the line width of a;
The line width of the line portion 26a and the connecting portion 26b connected to the electrode pattern 15 is wide, and the line width is approximately the same as the line portion 25a of the J conductive line 5 for a predetermined length from the connecting portion 26b to the line portion 26a. 21 and a power supply line 26 provided with a section 21.

[Effect]

In the present invention, when thermocompression bonding a conductive pattern to an electrode pattern, the line width of the transmission part of the power supply line is approximately the same as the line part of the conductive line, and the heat conduction is approximately uniform. 'It is connected to the electrode pattern at approximately the same temperature as the J line.

〔Example〕

Hereinafter, the configuration of an embodiment of the present invention will be described with reference to the drawings.

In FIGS. 1 to 3, 11 is a liquid crystal panel, and this liquid crystal panel 11 has a liquid crystal material sealed between a front panel 12 and a rear panel 13 formed of transparent glass. On each opposing surface of the panel 12.13, a plurality of transparent segment electrodes 14.14 constituting a liquid crystal picture element are arranged in a matrix shape, spaced apart and facing each other. A plurality of electrode patterns 15 are disposed on the end face along the front and rear directions of the front panel 12 . In this liquid crystal panel 11, by applying a voltage between the segment electrodes 14 and 14 of the front panel 12 and the rear panel 13, the arrangement of the molecules of the liquid crystal material changes and colors are generated, causing the picture elements of the liquid crystal display to change. Configure.

21 is a flexible board; this flexible board 21
In this case, a plurality of conductive patterns 23 made of, for example, copper foil are arranged in parallel inside cover lays 22, 22, which are elastic and insulative and made of, for example, polyimide resin. It is composed of On the lower surface of one end of the flexible substrate 21, the coverlay 22 is cut out to expose the ends of a plurality of conductive patterns 23, and a connection opening is provided for connecting the conductive patterns 23 to the electrode patterns 15 of the liquid crystal panel 11. 24 is formed.

The conductive pattern 23 connects each segment electrode 1 on one pole side.
4, and a power supply line 26 that is connected to the segment electrode 14 connected to the conductive line 25 and all other paired electrodes. This conductive line 25 is
With respect to a, the line width of the connection part 25a with the dimension of the interval 11 facing from the connection opening 24 is formed thick for connection with the electrode pattern 15, and the power supply line 26 is formed with a line width of the line part 26a. is formed thicker than the line portion 25a of the conductive line 25 because of its large current capacity, and the line width of the connecting portion 26b connected to the electrode pattern 15 is formed thicker for connection. A conductive portion 27 having substantially the same line width as the line portion 25a of the conductive line 25 is formed at a predetermined interval 12 from the side toward the line portion 26a.

Further, on the lower surface of the flexible substrate 21, a control integrated circuit 28 for applying voltage to each segment electrode 14 is arranged to be connected to each conductive pattern 23.

Next, in order to electrically connect the flexible substrate 21 to the liquid crystal panel 11, the ends of the flexible substrate 21 and the surface of the liquid crystal panel 11 are aligned, and each electrode pattern 15 is connected to each conductive pattern 23 corresponding thereto. By placing the solder 31 and thermocompression bonding, the electrode pattern 15 and the conductive pattern 23 are electrically connected via the solder 31.

A conductive pattern 23 is soldered 31 to this electrode pattern 15.
When thermocompression bonding is performed via the connecting portions 25b and 26b, heat is conducted and escapes from the connecting portions 25b and 26b to the line portions 25a and 26a, but the line width of the transmission portion 27 of the power supply line 26 is approximately equal to the line portion 25a of the conductive line 25. The connection part 26b of the power supply line 26 is connected to the solder 31 at approximately the same temperature as the connection part 25b of the conductive line 25, and the heat conduction is approximately uniform. Connected securely.

Note that this liquid crystal panel 11 is configured such that a large number of liquid crystal panels 11 are arranged vertically and horizontally with the front surface thereof being flat to form one large-sized liquid crystal display device.

(Effects of the Invention) According to the present invention, since the conductive part having substantially the same line width as the line part of the conductive line is provided in the power supply line of the conductive pattern, when the conductive pattern is thermocompression bonded to the electrode pattern, Heat conducts from the connection part to the line part and escapes, but the line width of the transmission part of the power supply line is approximately the same as that of the conductive line, and the heat conduction is approximately equal, so the power supply line is similar to the conductive line. It is connected to the electrode pattern at approximately the same temperature, ensuring a reliable connection similar to a conductive line, and improving product yield.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway bottom view showing an embodiment of the flexible substrate of the present invention, Fig. 2 is a longitudinal cross-sectional view of the flexible substrate in use, Fig. 3 is a perspective view of the flexible substrate, and Fig. 4 is a perspective view of the flexible substrate in its idle state. FIG. 2 is a partially cutaway bottom view of a conventional flexible substrate. 15... Electrode pattern, 21... Flexible substrate, 2
3. Conductive pattern, 25. Conductive line, 25a.
・Line portion, 25b ・・Connection portion, 26 ・・Power line, 26a ・・Line portion, 26b ・・・Connection portion, 27・
・Conduction part.

Claims (1)

[Claims] (1) In a flexible substrate having a conductive pattern that is connected to the electrode pattern of the object to be connected by thermocompression bonding, the conductive pattern has a line width of the connection part connected to the electrode pattern that is thicker than the line width of the line part. A conductive line having a conductive line connected to the line portion and the electrode pattern has a wide line width, and a conductive portion having a predetermined length from the connecting portion to the line portion and a line width that is approximately the same as the line portion of the conductive line. A flexible circuit board characterized by consisting of a power supply line.