JPH11185850A - Connection structure of circuit substrate and judging method for connection state of circuit substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To judge the connection state of two signal wires. SOLUTION: A first signal wire 21 is formed into one part 21a and the other part 21b electrically insulated from each other, and the parts 21a, 21b and a second signal wire 23 are connected by an anisotropic conductive adhesive (ACF) 26. In the state that the first signal wire 21 and the second signal wire 23 are properly connected, those parts 21a, 21b are electrically connected with the second signal wire 23, so that the connection state of the first signal wire 21 and the second signal wire 23 can be judged by transmitting a signal through either one of the parts 21a, and 21b and detecting the signal by the other 21a or 21b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit board connection structure for electrically connecting two circuit boards, and a method for determining the connection state.

[0002]

2. Description of the Related Art Conventionally, various types of circuit board connection structures for electrically connecting two circuit boards have been used. One example will be described with reference to FIG.

FIG. 1 is a plan view showing an example of the overall configuration of a conventional liquid crystal device. The liquid crystal device 1 shown in FIG. 1 includes a liquid crystal panel P that displays various kinds of information using liquid crystal. The liquid crystal panel P includes a pair of glass substrates 2 and 3 arranged with a gap therebetween; And a liquid crystal (not shown) sandwiched between the glass substrates 2 and 3.

Electrodes such as information electrodes and scanning electrodes are formed on the inner surfaces of the glass substrates 2 and 3, respectively, and extend to near the edges of the glass substrates 2 and 3. Also, these electrodes have multiple TCPs.
The peripheral circuit board 9 is connected via a (Tape Carrier Package) 7, and various signals are supplied from the peripheral circuit board 9 to the liquid crystal panel P.

FIG. 2 is a plan view showing an example of the detailed structure of the TCP. The TCP 7 has a flexible film 7a made of a polyimide resin, and the flexible film 7a is integrated into a chip. The mounted drive circuit 7b is mounted by a TAB method (Tape Automated Bonding method) and fixed by a sealing material 7c (see FIG. 3). The copper wiring pattern 7 extends linearly from the drive circuit 7b to both ends of the flexible film 7a.
d, 7e (hereinafter referred to as “input lead 7d”).
"Output lead 7e"). Of these, input lead 7
d, as shown in FIG. 3, the peripheral circuit board (P) is connected by a connecting member 10 such as solder or anisotropic conductive adhesive (ACF).
The output lead 7e is connected to the liquid crystal panel P (more precisely, its electrode) by an anisotropic conductive adhesive (ACF) 11.

Incidentally, the pitch of the TCP-side input leads 7d is as small as about 0.2 to 0.5 mm, and when the TCP 7 is connected to the peripheral circuit board 9, it is necessary to accurately position them. Therefore, the following method has been adopted.

That is, in the TCP 7, as shown in FIG. 2, the leads 7f, 7
g (hereinafter, referred to as “TCP-side dummy leads 7f, 7g”) are formed in U-shape on both sides of the input lead 7d. In the peripheral circuit board 9, as shown in FIG. 4, the leads 9a, 9
b, 9c, 9d (hereinafter “substrate-side dummy leads 9a, 9d”).
b, 9c, 9d "). These substrate-side dummy leads 9a, 9b, 9c, 9d are formed in a state where they are not electrically connected to each other.
In a state where the TCP 7 is at an appropriate connection position, the TCP 7 faces four ends of the TCP-side dummy leads 7f and 7g. Then, these substrate-side dummy leads 9a, 9
The b, 9c, 9d and the TCP side dummy leads 7f, 7g are connected by an anisotropic conductive adhesive (ACF) 10. Further, the substrate-side dummy leads 9a, 9b, 9c, 9d
Is TCP7 (TCP in a state where it is connected to an appropriate position)
7), and terminals 12a, 12b, 12c, 12d are connected to respective ends.

Now, assuming that the TCP 7 and the peripheral circuit board 9 are connected in a proper positional relationship, the adjacent terminals 1
2a and 12b are substrate-side dummy leads 9a and 9b, anisotropic conductive adhesive (ACF) 10, and TCP-side dummy leads 7;
g and the other terminal 12
c and 12d should also be in a conductive state.
Therefore, by measuring the resistance value between these adjacent terminals (12a, 12b or 12c, 12d), it can be determined whether the peripheral circuit board 9 and the TCP 7 have been connected well.

[0009]

In the conventional method, the connection state is determined only by the board-side dummy leads 9.
a, 9b, 9c, 9d and TCP side dummy leads 7f, 7
g, but does not directly determine the connection state between the TCP-side input lead 7d and the peripheral circuit board-side wiring. Therefore, even when the connection state of these dummy leads is good, the connection state between the TCP-side input lead 7d and the wiring on the peripheral circuit board side may not be good.

The TCP 7 has dummy leads 7f, 7f.
g needs to be provided separately, and it is considered that the TCP 7 becomes large in size, which may be a hindrance in mounting, causing a problem of an increase in the cost of the TCP 7.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a circuit board connection structure and a connection state determination method capable of determining a connection state between two signal lines.

It is another object of the present invention to provide a circuit board connection structure which can prevent the second circuit board from being enlarged.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a first circuit board having a first signal line formed on a surface thereof, and a first circuit board opposed to the first signal line. A second circuit board on which a second signal line is formed, a connecting member for electrically connecting the first and second signal lines,
In the connection structure of a circuit board provided with, the first signal line is divided into one part and another part in a state where the first signal line is electrically insulated from the other part at the connection part, and Are connected to the second signal line via the connection member.

Further, according to the present invention, a first signal line formed on a surface of a first circuit board, and a second signal board formed on the second circuit board so as to face the first signal line, and In a connection state determining method for determining whether or not both signal lines of a second signal line electrically connected to one signal line via a connecting member are properly connected, the first signal line may be connected to the first signal line. , Which is divided into one part and another part in an electrically insulated state, and a signal of an arbitrary waveform is input from any one of the one part or the other part, and Measuring the signal waveform and comparing the input signal waveform with the measured signal waveform,
Judge the connection state between the signal line and the second signal line,
It is characterized by the following.

Further, according to the present invention, a first signal line formed on a surface of a first circuit board, and a second signal board formed on a second circuit board so as to face the first signal line, and 1
In a connection state determining method for determining whether or not both signal lines of a second signal line electrically connected to a signal line via a connecting member are properly connected, the first signal line includes:
One part and the other part are separated in an electrically insulated state, a resistance value between the one part and the other part is measured, and the measured resistance value The connection state between the first signal line and the second signal line is determined from the following.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS.
An embodiment of the present invention will be described.

FIG. 5 is a side view showing one embodiment of a circuit board connection structure according to the present invention. The connection structure 20 of the circuit board according to the present embodiment has a first signal line 21 on the surface.
Formed on the first circuit board 22 and the first signal line 2
2 in which the second signal line 23 is formed so as to face
And the first and second signal lines 21 and 23 are electrically connected by a connection member 26. Further, the first signal line 21 is divided into one part 21a and another part 21b so as to be electrically insulated from each other, and the one part 21a and the other part 21b are both separated from each other. It is connected to the second signal line 23 via a connection member 26.

FIG. 6 is a plan view showing the structure of the first circuit board 22. As shown in FIG. 6, one auxiliary signal line 27 is formed on the first circuit board 22, and A position where the one auxiliary signal line 27 is electrically connected to the one portion 21a and does not interfere with the second circuit board 25 (a position which does not interfere with the TCP 25 which is connected to an appropriate position. The same). In this case, the first inspection terminal 2 is located at a position on the one auxiliary signal line 27 where the first inspection terminal 2 does not interfere with the second circuit board 25.
8 should be arranged.

Further, another auxiliary signal line 29 is formed on the first circuit board 22, and the other auxiliary signal line 29 is
It is preferable that the second circuit board 25 is electrically connected to the other portion 21b and extends to a position where it does not interfere with the second circuit board 25. In this case, the second auxiliary signal line 29 is located at a position where it does not interfere with the second circuit board 25.
Inspection terminals 30 may be arranged.

As the connecting member 26, an anisotropic conductive adhesive or solder can be used.

The first circuit board 22 includes:
As shown in FIG. 7, a peripheral circuit board arranged around the liquid crystal element P can be mentioned.
For example, a flexible circuit board disposed between the peripheral circuit board 22 and the liquid crystal element P can be used.

Next, an embodiment of a connection judging method for judging the connection state between the first signal line 21 and the second signal line 23 in the connection structure 20 of the circuit board will be described.

In the connection structure 20 of the circuit board, a signal having an arbitrary waveform is inputted from one of the one part or the other part (21a or 21b), and a signal is inputted from the other part (21b or 21a). The waveforms are measured, and these waveforms (the input signal waveform and the measured signal waveform) are compared.

Here, the first signal line 21 and the second
And the other portion 21b are in a state of conduction through the second signal line 23 when the two signal lines 23 are appropriately connected to each other. (The input signal waveform and the measured signal waveform) are the same. Therefore, from the comparison of these two waveforms, the first signal line 21 and the second signal line 23
Can be determined.

The connection between the two signal lines 21 and 23 may be determined by measuring the resistance between the one part 21a and the other part 21b.

That is, if the first signal line 21 and the second signal line 23 are properly connected, the one portion 21a and the other portion 21b are in a conductive state as described above. , The measured resistance value (the resistance value between the one part 21a and the other part 21b) is the line or wiring resistance value of the one part 21a, the one part 21a and the second signal A connection resistance value between the line 23 (resistance value of the connection member 26), a line or wiring resistance value of the second signal line 23 between one part 21a and another part 21b, and another part 21b. It should be equal to the sum of the resistance value of the connection resistance value (the resistance value of the connection member 26) between the second signal line 23 and the line or wiring resistance value of the other portion 21b. Since it is known, and can be calculated, and the connection state can be determined as described above. It can be.

Next, effects of the present embodiment will be described.

According to the present embodiment, the first signal line 21
The connection state between the signal line and the second signal line 23 can be determined, and defective products can be checked.

Further, the circuit board connection structure 20 according to the present embodiment is capable of determining the connection state of the signal lines 21 and 23 as described above, while providing a mechanism for determining the connection state (the conventional structure). There is no need to provide any TCP-side dummy leads 7g and 7f) on the second circuit board 25 side, so that the second circuit board 25 can be prevented from being enlarged.

Further, by monitoring the one portion 21a or the other portion 21b while the connection structure 20 of the circuit board is being driven, the signals input to the signal lines 21 and 23 in the driven state are monitored. Can be monitored.

[0031]

Embodiment 1 In this embodiment, a liquid crystal device 40 shown in FIG. 7 was prepared using the above-described circuit board connection structure, and the connection state was checked by the above-described method.

Reference numeral P in the figure denotes a liquid crystal panel (liquid crystal element), and reference numeral 22 denotes a first liquid crystal panel disposed around the liquid crystal panel P.
Is a peripheral circuit board as a circuit board. Also, reference numeral 2
Reference numeral 5 denotes a flexible circuit board (hereinafter, referred to as “TCP”) as a second circuit board disposed between the peripheral circuit board 22 and the liquid crystal panel P.

The surface of the peripheral circuit board 22 is
The wiring (first signal line) 21 is formed as shown in FIG.
An input lead (second signal line) 23 was formed on the surface of P25 so as to face the wiring 21. The wiring 21
The connection terminal 21a and the connection terminal 21b are partially cut off at a portion facing the input lead 23, and are electrically insulated from each other. The output lead of the TCP 25 was connected to an electrode on the liquid crystal panel side. Furthermore, T
The CP25 includes a driving circuit 25 similar to that shown in FIG.
b.

In this embodiment, as shown in FIG.
A signal wiring 31 is connected to the connection terminal 21a as one part, and various signals from a control circuit (not shown) are input to the signal wiring 31.

On the surface of the peripheral circuit board 22, an auxiliary wiring (one auxiliary signal line) 27 which is electrically connected to the connection terminal 21a and extends to a position where it does not interfere with the TCP 25 is formed. An inspection check pattern (first inspection terminal) 28 was connected to an end of the auxiliary wiring 27.

Further, on the surface of the peripheral circuit board 22, an auxiliary wiring (another auxiliary signal line) which is electrically connected to the connection terminal 21b as another part and extends to a position which does not interfere with the TCP 25 ) 29 is formed, and an inspection check pattern (second inspection terminal) 30 is provided at the end of the auxiliary wiring 29.
Connected.

The surface of the peripheral circuit board 22 was covered with a solder resist 42, and only the connection terminals 21a and 21b and the inspection terminals 28 and 30 were opened.

The input lead 23 on the TCP side and the connection terminals 21a and 21b on the peripheral circuit board side were electrically connected by an anisotropic conductive adhesive (ACF) 26 as a connection member. This connection was made by thermocompression bonding from above TCP 25 at the same time.

Next, a signal having a predetermined waveform was input from the signal wiring 31 to the connection terminal 21a, and a signal waveform was measured in the check pattern 30 for inspection. Then, by comparing these waveforms (the input signal waveform and the measured signal waveform), the connection state between the wiring 21 and the input lead 23 was determined. (Embodiment 2) In the liquid crystal device 40 having the above-described structure, the inspection check pattern 28 and the inspection check pattern 3
A resistance value between 0 and the wiring 21 and the input lead 23 is measured.
The connection status with was determined.

[0040]

As described above, according to the present invention,
The connection state between the first signal line and the second signal line can be determined,
Defective products can be checked.

Further, the circuit board connection structure according to the present invention is capable of determining the connection state of the signal line as described above, while providing a mechanism for determining the connection state (conventional TC board).
There is no need to provide any P-side dummy leads 7g, 7f) on the side of the second circuit board, and it is possible to prevent the second circuit board from being enlarged.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of the overall configuration of a conventional liquid crystal device.

FIG. 2 is a plan view showing an example of a detailed structure of TCP.

FIG. 3 is a side view for explaining a connection state and the like between a liquid crystal panel, a peripheral circuit board, and a TCP in a conventional liquid crystal device.

FIG. 4 shows a peripheral circuit board and a TC in a conventional liquid crystal device.
FIG. 3 is a plan view for explaining a connection state with P and the like.

FIG. 5 is a side view showing one embodiment of a circuit board connection structure according to the present invention.

FIG. 6 is a plan view showing the structure of a first circuit board used in the present invention.

FIG. 7 is a diagram showing a configuration of an entire liquid crystal device to which the present invention is applied.

[Explanation of symbols]

 Reference Signs List 20 connection structure of circuit board 21 wiring (first signal line) 21a connection terminal (one part) 21b connection terminal (other part) 22 peripheral circuit board (first circuit board) 23 input lead (second signal) 25) Flexible circuit board (second circuit board) 26 Anisotropic conductive adhesive (connection member) 27 Auxiliary wiring (one auxiliary signal line) 28 Inspection check pattern (first inspection terminal) 29 Auxiliary wiring (Other auxiliary signal lines) 30 Check pattern for inspection (second inspection terminal) 40 Liquid crystal device P Liquid crystal panel (liquid crystal element)

Claims (10)

[Claims] A first circuit board having a first signal line formed on a surface thereof; a second circuit board having a second signal line formed so as to face the first signal line; A connection member for electrically connecting the first and second signal lines, wherein the first signal line is connected to one portion and another portion at the connection portion. The circuit board is divided into an electrically insulated state, and both the one part and the other part are connected to the second signal line via the connection member. Connection structure. 2. An auxiliary signal line is formed on the first circuit board, and the one auxiliary signal line is electrically connected to the one portion and is connected to the second circuit board. The circuit board connection structure according to claim 1, wherein the connection structure extends to a position where no interference occurs. 3. The circuit board connection structure according to claim 2, wherein a first inspection terminal is arranged at a position in the one auxiliary signal line that does not interfere with the second circuit board. 4. An auxiliary signal line is formed on the first circuit board, and the other auxiliary signal line is electrically connected to the other portion and is connected to the second circuit board. The connection structure for a circuit board according to any one of claims 1 to 3, wherein the connection structure extends to a position where no interference occurs. 5. The circuit board connection structure according to claim 4, wherein a second inspection terminal is arranged at a position in the other auxiliary signal line which does not interfere with the second circuit board. 6. The circuit board connection structure according to claim 1, wherein the connection member is an anisotropic conductive adhesive. 7. The circuit board connection structure according to claim 1, wherein the connection member is solder. 8. The first circuit board is a peripheral circuit board arranged around a liquid crystal element, and the second circuit board is arranged between the peripheral circuit board and the liquid crystal element. The circuit board connection structure according to claim 1, wherein the connection structure is a flexible circuit board. 9. A first circuit board formed on a surface of a first circuit board.
And a second signal line formed on the second circuit board so as to face the first signal line and electrically connected to the first signal line via a connection member. A connection state determination method for determining whether or not both signal lines are properly connected, wherein the first signal line is divided into a state in which one part and another part are electrically insulated. A signal having an arbitrary waveform is input from one of the one part and the other part, and a signal waveform is measured in the other part, and the input signal waveform and the measured signal waveform are A connection state between the first signal line and the second signal line is determined from the comparison. 10. A first signal line formed on a surface of a first circuit board, and a second signal line opposed to the first signal line.
Connection state determination for determining whether or not both signal lines of a second signal line formed on the circuit board and electrically connected to the first signal line via a connection member are properly connected. The method, wherein the first signal line is divided into one part and another part so as to be electrically insulated from each other, and a resistance value between the one part and the other part. Measure
And a connection state between the first signal line and the second signal line is determined from the measured resistance value.