JP2010091972A - Circuit device and method for inspecting the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems that a parasitic capacitance increases and a load when performing operation becomes greater if a terminal for inspection is further connected to a signal line for connecting a circuit and a connection terminal. <P>SOLUTION: The circuit device includes a circuit (2) which is disposed on a substrate (8), the connection terminal (4) which is disposed in a position apart from the circuit of the substrate, and relays the input or output signal of the circuit, a signal line (3) which connects the circuit and the connection terminal, a plurality of terminals (6) for inspection disposed at the substrate separately from the connection terminal, and branch wiring (31) which branches from the signal line, and is connected to each one of the plurality of the terminals for inspection. A switch (1) is disposed between the branches of the branch wiring and the terminal for the inspection. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a circuit device, particularly to a circuit device including a display element and a circuit for driving the display element, and an inspection method thereof.

  As display devices, liquid crystal display devices, organic EL display devices, and the like are known. In the display area of these display devices, display elements are arranged in a matrix, and display is performed by controlling the display elements by a pixel circuit arranged corresponding to the display elements. The display device includes a scanning line driving circuit that supplies a scanning signal to the scanning line and a data line driving circuit that supplies a data signal to the data line, and the pixel circuit is supplied via the scanning line and the data line. The display is performed by being driven by the signal. Further, an external connection terminal connected to the drive circuit is provided, and the drive circuit is controlled by supplying a control signal from the external connection terminal to the drive circuit.

  Generally, the drive circuit is composed of a thin film transistor (TFT), and the drive circuit may be defective due to TFT failure. Therefore, the operation of the drive circuit is inspected in advance in the manufacturing process. When inspecting this drive circuit, if an inspection signal is input by bringing the inspection probe into direct contact with the external connection terminal, the terminal surface is rubbed, the conductive film on the surface is peeled off, and the external connection terminal is deteriorated. Connection failure may occur between the terminal and the mounted component. Further, there is a problem that the peeled conductive film adheres between adjacent external connection terminals, thereby causing a short circuit and reducing the reliability of the display device.

For this reason, the display device disclosed in Patent Document 1 includes a branch for a signal line that connects a drive circuit and an external connection terminal, and includes an inspection terminal that is connected from the position where the branch is provided. As a result, when inspecting the drive circuit, the inspection probe is applied to the inspection terminal and an inspection signal is input to inspect the operation of the drive circuit in advance. Since there is no contact of the inspection probe on the external connection terminal used after the product is completed, connection failure or short circuit at that portion is prevented.
JP 2008-065015 A

  However, in the conventional technique, since the inspection terminal is further connected to the signal line connecting the drive circuit and the external connection terminal, the parasitic capacitance due to the addition of the inspection terminal is increased and becomes a load when displaying. As a result, the drive margin is reduced, and a malfunction may occur.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a circuit device capable of inspecting a circuit included in a display device and other circuit devices without degrading reliability and having a large driving margin during operation, and a method for manufacturing the circuit device. And

In order to achieve the above object, a circuit device according to the present invention provides:
A circuit provided on the substrate;
A connection terminal provided at a position away from the circuit of the substrate and relaying an input or output signal of the circuit;
Signal wiring for connecting the circuit and the connection terminal;
Inspection terminals provided separately from the connection terminals on the substrate;
A branch line branched from the signal line and connected to the inspection terminal;
A circuit device comprising:
A switch is provided between the branch of the branch wiring and the inspection terminal.

The circuit device inspection method according to the present invention includes:
On the board,
Circuit,
A connection terminal at a position away from the circuit;
Signal wiring connecting the circuit and the connection terminal;
An inspection terminal;
A branch wiring connecting the branch of the signal wiring and the inspection terminal;
A switch provided between the branch and the inspection terminal;
A circuit device inspection method comprising:
A. Providing a signal for closing the switch to a control line for controlling the opening and closing of the switch;
B. B. providing an input signal of the circuit to the branch wiring through the inspection terminal, or detecting an output signal of the circuit from the branch wiring; The method includes a step of opening the inspection terminal.

  According to the present invention, an inspection terminal is used to inspect the operation of the circuit, and during normal circuit operation, the inspection terminal is separated by a switch to remove the parasitic capacitance, thereby improving the yield in the manufacturing process. In addition, the driveable range during normal operation can be expanded.

  Hereinafter, the best mode for carrying out a display device according to the present invention will be specifically described with reference to the drawings.

  Examples of the circuit device used in the present invention include a display device using a liquid crystal display element, an organic EL element, an inorganic EL element, a light emitting diode, and the like. The display device is a circuit device including a circuit provided for each pixel and a circuit provided around a matrix arrangement of pixels in order to drive these display elements. However, the present invention is not applied only to a display device, and a circuit and a connection terminal are provided on a substrate, and an input signal is supplied to the circuit through the connection terminal or a signal output from the circuit is detected. Applicable to all configured circuit devices.

  In the case of a display device, display elements are arranged in a matrix in the display area, and display is performed by controlling the display elements by pixel circuits arranged corresponding to the display elements. The display device includes a scanning line driving circuit that supplies a scanning signal to the scanning line and a data line driving circuit that supplies a data signal to the data line, and the pixel circuit is supplied via the scanning line and the data line. The display is performed by being driven by the signal. Further, an external connection terminal connected to the drive circuit is provided, and the drive circuit is controlled by supplying a control signal from the external connection terminal to the drive circuit.

  The display device includes various circuits as described above and can be regarded as a circuit device. A pixel circuit, a driver circuit, a signal line, and the like that constitute the circuit device are formed over a glass substrate. A plastic substrate may be used instead of the glass substrate.

  A circuit on a glass substrate or a plastic substrate is usually composed of a thin film transistor (TFT) apart from a passive element such as a capacitor and wiring. As the active layer of the TFT, a non-single crystal semiconductor such as amorphous silicon, polycrystalline silicon, or microcrystalline silicon is preferably used. A single crystal semiconductor such as single crystal silicon may be used for the active layer.

  However, not all the circuits are formed of TFTs, but at least a part of the scanning line driving circuit or the data line driving circuit of the display device may be formed of an integrated circuit (IC) chip and mounted on the substrate. is there. The present invention can also be applied to such a circuit device.

  FIG. 1 is a schematic diagram showing the configuration of the circuit device of the present invention.

  The circuit device 10 includes a substrate 8 on which a circuit 2 and a connection terminal 4 for external connection are provided. When operating the circuit 2, the external connection terminal 4 transmits a signal sent from an external circuit (not shown) to the signal wiring and inputs the signal to the driving circuit 2 through the signal wiring 3. There may be a plurality of signal wirings 3, and some of them may be signal wirings for transmitting a signal generated in the drive circuit to an external circuit (not shown) through the external connection terminal 4. Thus, the external connection terminal 4 plays a role of relaying the input / output signal of the circuit 2 and the signal of the external circuit.

  Since the external connection terminal is provided at one end of the board and the circuit 2 is away from the board on the board, the signal wiring 3 connecting the two is connected between the surrounding wiring and the power source according to the length. Have parasitic capacitance. Parasitic capacitance causes signal delays and waveform rounding and should be minimized.

  In the signal wiring 3, another wiring 31 (hereinafter referred to as a branch wiring) 31 branches from the branch 5, and is led to an inspection terminal 6 provided separately from the external connection terminal 4 through the switch 1. .

  The switch 1 is opened and closed by a signal on the control line 7. The control line 7 is connected to a terminal of the inspection terminal 6 to which the branch wiring is not connected, and is connected to an external signal generation circuit (not shown) through this terminal. Therefore, there are a plurality of inspection terminals 6, some of which are connected to the branch wiring 31 and the rest are connected to the control line 7 of the switch 1.

  The inspection terminal 6 is also the same as the external connection terminal 4 in that it has a role of relaying the signal of the circuit 2 to the outside. However, the external connection terminal 4 relays a signal for using the circuit device 10, whereas the inspection terminal 6 is used for the inspection of the circuit 2 in the course of manufacturing the circuit device 10. It is not used when the actual circuit device 10 is used. Because of this difference, hereinafter, the external connection terminals 4 that transmit signals during actual use are simply referred to as connection terminals 4, and the terminals that transmit signals only during inspection are distinguished as inspection terminals 6.

  The inspection terminal 6 does not necessarily have to be on the same side of the substrate 8 as the connection terminal 4, and may be on a different side. Moreover, you may arrange | position in the internal empty space instead of the edge part of the board | substrate 8. FIG.

  When the switch 1 is turned on, the branch 5 and the inspection terminal 6 are electrically connected. When the switch 1 is turned off, the branch 5 and the inspection terminal 6 are electrically disconnected.

  The switch 1 is preferably arranged in the vicinity of the branch 5 in order to reduce the parasitic capacitance of the signal wiring 3 when it is off. A TFT is preferably used as the switch 1 and is formed by the same process as the TFT constituting the circuit 2 and others.

  FIG. 2 shows the configuration of the switch 1. 2A shows an N-type TFT, FIG. 2B shows a P-type TFT, and FIG. 2C shows a transfer gate composed of an N-type TFT and a P-type TFT. 2, S1, S2, S3, and S4 are control terminals (TFT gate terminals) for controlling on / off of the switch, and are connected to one of the inspection terminals 6 through the control line 7 shown in FIG. Has been.

  When inspecting the operation of the circuit 2 and the operation of other parts through the manufacturing process of the circuit device 10, the inspection probe is brought into contact with the inspection terminal 6, and the control line is connected to one of the inspection terminals 6. 7 is input to turn on the switch 1. At the same time, an inspection signal is input to the circuit 2 from the other inspection terminals 6. Further, the output of the circuit 2 may be detected from the inspection terminal 6. After completion of the inspection, all the inspection terminals 6 are opened, and instead, a flexible cable is bonded to the connection terminal 4 to connect an external circuit.

In the operation as the circuit device 10 after completion of the product, the switch 1 is turned off in order to electrically disconnect the branch 5 and the inspection terminal 6. Since the inspection terminal 6 is not used for the operation after completion of the product and is open (not connected to the external circuit), it is necessary to keep the switch 1 open even at that time. For this reason, the control line 7 of the switch is as follows in the panel.
(1) When the switch 1 is the N-type TFT of FIG. 2A, S1 is pulled down to an off potential via a resistor.
(2) When the switch 1 is the P-type TFT of FIG. 2B, S2 is pulled up to an off potential via a resistor.
(3) When the switch 1 is a transfer gate composed of an N-type TFT and a P-type TFT in FIG. 2C, S4 is pulled down to an off potential through a resistor, and S3 is turned off through a resistor. Pull up to.

  In the case of FIG. 2 (C), as shown in FIGS. 3 (A) and 3 (B), a configuration in which the control line of the switch 1 is made one by using an inverter may be adopted. In the case of FIG. 3A, the control line 7 of the switch 1 connected to S5 is preferably pulled down, and in the case of FIG. 3B, the control line 7 connected to S6 is preferably pulled up.

  In addition, the size of the inspection terminal 6 is preferably larger than the size of the connection terminal 4 and the interval between adjacent terminals is preferably increased. As a result, alignment when the inspection probe is brought into contact is facilitated, and the reliability of the inspection is improved.

  FIG. 4 is a plan configuration diagram of an active matrix organic EL display device according to an embodiment of the present invention. Those having the same function as those in FIG. 1 or those having the same function are denoted by the same reference numerals.

  In the organic EL display device 20 of the present embodiment, the organic EL elements are arranged in a matrix, and the pixel circuits arranged corresponding to the organic EL elements are arranged in the same matrix to form an image. An organic EL element is driven by the pixel circuit, and an image is displayed.

  A data line driving circuit 11 and a scanning line driving circuit 12 are formed along two sides of the image. Outputs of the data line driving circuit 11 and the scanning line driving circuit 12 are input to an image pixel circuit (not shown). The data line driving circuit 11 supplies an image data signal to each pixel circuit of the image. The scanning line driving circuit 12 supplies a scanning signal to each pixel circuit of the image.

  In this embodiment, the combination of the image pixel circuit, the data line driving circuit 11 and the scanning line driving circuit 12 corresponds to the circuit 2 in FIG.

  A connection terminal 4 and an inspection terminal 6 are formed at the end of the substrate 8.

  A signal wiring 3 extends from each of the connection terminals 4 and is connected to the data line driving circuit 11 and the scanning line driving circuit 12. The signal wiring 3 is a wiring provided on the substrate, and a branch 5 is provided in the middle thereof. The wiring extending separately from the branch 5 is connected to the inspection terminal 6 via the switch 1. A control line 7 of the switch 1 extends from another inspection terminal 6 and is connected to the on / off control terminal of the switch 1. In the present embodiment, two control lines 7 of the switch 1 are provided so that the data line driving circuit 11 and the scanning line driving circuit 12 can be separately inspected, and each of them is led to another inspection terminal 6. It has been.

  The connection terminal 4 is connected to an external circuit (not shown) such as an image processing circuit, a power supply circuit, and a timing controller via a flexible flat cable (not shown).

  A power source and a control signal for driving peripheral circuits such as the data line driving circuit 11 and the scanning line driving circuit 12 and a power source and an image signal supplied thereto are supplied to the connection terminal 4 from these external circuits.

  The inspection terminal 6 is a terminal for supplying an inspection signal when inspecting the pixel circuit of the data line driving circuit 11 and the scanning line driving circuit 12 during the manufacture of the organic EL display device 20. There are a plurality of terminals, and control signals and image signals for inspection are supplied, and output signals returned from the circuit to be inspected are received. The control signal for inspection includes a switch control signal for turning on the switch 1.

  At the time of inspection, an inspection probe having a needle-like tip is brought into contact with the inspection terminal 6, and an inspection power source and a signal are transmitted and received through the probe.

  The inspection is performed before or after the display element is formed, or both. When a display element is formed and inspection is performed by looking at the display state, there is no need to have a terminal for receiving an output signal returned from the circuit to be inspected.

  On the contrary, by performing an inspection before forming the display element, a product having a defective circuit can be removed. After the inspection, the connection of the external circuit to the inspection terminal 6 is removed, and all the inspection terminals 6 are opened. Since the inspection terminal 6 is not used during the display operation after the product is completed, a cable or the like is not connected.

  By providing the inspection terminal 6, the inspection probe is not brought into contact with the connection terminal 4 to which a cable or the like is connected. As a result, the terminal surface is rubbed, the conductive film on the surface is peeled off, the connection terminal 4 is deteriorated, and there is no possibility that a connection failure occurs between the connection terminal 4 and a mounting component such as a cable. Further, the peeled conductive film adheres between the adjacent connection terminals, thereby causing a short circuit and eliminating the problem of reducing the reliability of the organic EL display device 20. Since a cable or the like is not connected to the inspection terminal 6, it is not necessary to consider the above problem.

  In order to reduce the cost by reducing the size of the connection cable to be mounted, the connection terminals 4 are often arranged at a narrow pitch, and it is difficult to align and contact the inspection probes with the connection terminals 4. The inspection terminals 6 are arranged with larger dimensions (size) and intervals than the connection terminals 4 so that the probe can be easily aligned.

  After the display device is completed, display is performed by supplying control signals, image signals, and power from the connection terminals 4 on which the connection cables are mounted.

  At this time, the control line 7 of the switch 1 is pulled up or pulled down via a resistor, and the switch 1 is also in an open state.

  Thus, after the product is completed, the switch 1 is turned off, and the signal wiring 3 and the inspection terminal 6 are electrically disconnected. Therefore, the large parasitic capacitance of the inspection terminal 6 is the signal wiring 3. Does not affect. As a result, the drive margin is prevented from being lowered, and malfunction of the display device can be prevented.

  FIG. 5 is a plan view of an active matrix type organic EL display device according to a second embodiment of the present invention.

  In the organic EL display device 30 according to the present embodiment, as in the first embodiment, the organic EL elements are arranged in a matrix, and the organic EL elements are controlled by a pixel circuit arranged corresponding to the organic EL elements. Is done.

  A data line driving circuit 11 for supplying image data signals to the display area is formed along the lower side of the display area. A scanning line driving circuit 12 is formed along the right side. Outputs of the data line driving circuit 11 and the scanning line driving circuit 12 are input to the pixel circuit.

  The present embodiment is different from the circuit device 10 of FIG. 1 and the organic EL display device 20 of Embodiment 1 in that an integrated circuit chip (IC chip) 28 is mounted on the organic EL display device 30. An IC chip mounting terminal 29 is provided on the substrate, and the IC chip mounting terminal 29 and the pad of the IC chip 28 are electrically and mechanically connected by direct contact or through an anisotropic conductive material. Is done.

  The IC chip 28 supplies a control signal and an image signal to the data line driving circuit 11 and the scanning line driving circuit 12 through the signal wiring 23 connected to the IC chip mounting terminal 29.

  The IC chip 28 has a part of the function of the data line driving circuit 11 in the first embodiment, and has a function requiring a particularly high driving frequency.

  Also in this embodiment, a combination of the image pixel circuit, the data line driving circuit 11, and the scanning line driving circuit 12 corresponds to the circuit 2 in FIG.

  The signal wiring 23 for sending signals to the data line driving circuit 11 and the scanning line driving circuit 12 corresponds to the signal wiring 3 in FIG. 1, and the IC chip mounting terminal 29 which is the terminal of the signal wiring 23 is connected to the connection terminal in FIG. It corresponds to 4. Other components denoted by the same reference numerals as those in FIG. 1 have the same functions.

  At the end of the substrate 8, an external extraction terminal 14 for relaying an IC signal and an inspection terminal 6 are formed. The external lead terminal 14 is connected to the IC chip mounting terminal 29 via the signal wiring 23A, and as a result, connected to the IC chip 28.

  The organic EL display device 30 includes a plurality of inspection terminals 6. The signal wiring 23 connected to the IC chip 28 and the data line driving circuit 11 or the scanning line driving circuit 12 is provided with a branch 5. The branch 5 and the inspection terminal 6 are connected via the switch 1. Has been. At least one of the inspection terminals 6 is connected to the on / off control terminal of the switch 1 via the control line 7 of the switch 1. The plurality of inspection terminals 6 are arranged in an empty space on the substrate.

  Control signals, image signals, and power for driving the IC chip 28 are supplied to the external extraction terminal 14. The external extraction terminal 14 is electrically and mechanically connected to a connection cable made of a flexible substrate via an anisotropic conductive material. As the connection destination, there is an external substrate (not shown) provided with an image processing circuit, a power supply circuit, a timing controller, and the like. Can be achieved.

  According to the present embodiment, the inspection terminal 6 is connected to the data line driving circuit 11 or the scanning line driving circuit 12 via the switch 1, and even before the IC chip 28 is mounted, the data line driving circuit 11 or the scanning terminal 6. The line drive circuit 12 can be inspected.

  As an inspection, a signal for bringing the needle-like inspection probe into contact with the inspection terminal 6 and turning on the switch 1 to the inspection terminal 6 connected to the control line 7 of the switch 1 before the mounting of the IC chip 28. Enter. At the same time, an inspection signal is supplied from the inspection terminal 6 connected to the data line driving circuit 11 and the scanning line driving circuit 12 via the switch 1.

  When the inspection is performed in this way, the inspection probe is not brought into contact with the IC chip mounting terminal 29. As a result, the terminal surface is rubbed, the conductive film on the surface is peeled off, the IC chip mounting terminal 29 is deteriorated, and there is little possibility that a connection failure occurs between the IC chip mounting terminal 29 and the IC chip 28. Become. In addition, the peeled conductive film adheres to the adjacent IC chip mounting terminals 29, thereby causing a short circuit and reducing the reliability of the display device. On the other hand, since the mounting parts are not connected to the inspection terminal 6 even if the inspection probe is brought into contact with the inspection terminal 6, it is not necessary to consider the above problem.

  In general, the IC chip mounting terminals 29 are often arranged at a narrow pitch, and it is difficult to align and contact the inspection probes. Therefore, the IC chip mounting terminal 29 itself cannot be an inspection terminal. Instead, the inspection terminal 6 is provided, and the inspection terminal 6 is arranged in a relatively larger size than the IC chip mounting terminal 29, whereby a highly reliable inspection can be easily performed.

  After the inspection, if there is no problem in the operation of the display device, the IC chip 28 may be mounted. If a defect is found in the display device, the IC chip 28 is not mounted. This eliminates the waste of mounting the IC chip 28 on a display device having a defective circuit.

  In the operation as a normal display device, the inspection terminal 6 is open, and the IC chip 28 is supplied by supplying a control signal, an image signal, and power from the external extraction terminal 14 to which the cable is connected to the IC chip 28. Operate. Then, a control signal and an image signal are supplied from the IC chip 28 to the data line driving circuit 11 and the scanning line driving circuit 12, and display is performed. As the switch 1, any of the above-described FIGS. 2A, 2B, and 2C can be employed. The control line 7 of the switch 1 is pulled up or pulled down to a potential for turning off the switch through a resistor.

  By performing the display operation in this manner, the switch 1 is in an off state during the display operation, and the inspection terminal 6 is electrically disconnected. Therefore, the parasitic capacitance due to the addition of the inspection terminal 6 There is no increase, and it is possible to avoid the possibility of malfunctions and to suppress a decrease in drive margin.

  The display devices of the above-described embodiments can be applied to various electronic devices.

  FIG. 6 is a block diagram of a digital still camera system as an electronic apparatus in which the present invention is used. In the figure, 50 is a digital still camera system, 51 is an imaging unit, 52 is a video signal processing circuit, 53 is a display panel, 54 is a memory, 55 is a CPU, and 56 is an operation unit.

  In FIG. 6, an image captured by the imaging unit 51 or an image recorded in the memory 54 can be signal-processed by the image signal processing circuit 52 and viewed on the display panel 53. The CPU 55 controls the imaging unit 51, the memory 54, the video signal processing circuit 52, and the like by input from the operation unit 56, and performs shooting, recording, reproduction, and display suitable for the situation. In addition, the display panel 53 can be used as a display unit of various electronic devices.

It is the schematic explaining this invention. It is an example of composition of a switch concerning the present invention. It is an example of composition of a switch concerning the present invention. This is an active matrix organic EL display device according to the first embodiment. This is an active matrix organic EL display device according to a second embodiment. It is a block diagram which shows the whole structure of the digital still camera system using the display apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Switch 2 Circuit 3,23,23A Signal wiring 4 Connection terminal 5 Branch 6 Inspection terminal 7 Switch control line 8 Organic EL display device 9 Display area 10 Circuit device 11 Data line drive circuit 12 Scan line drive circuit 14 External extraction terminal 28 IC chip 29 IC chip mounting terminal 20, 30 Display device 50 Digital still camera system 51 Imaging unit 52 Video signal processing circuit 53 Display panel 54 Memory 55 CPU
56 Operation unit

Claims (10)

A circuit provided on the substrate;
A connection terminal provided at a position away from the circuit of the substrate and relaying an input or output signal of the circuit;
Signal wiring for connecting the circuit and the connection terminal;
Inspection terminals provided separately from the connection terminals on the substrate;
A branch line branched from the signal line and connected to the inspection terminal;
A circuit device comprising:
A circuit device, wherein a switch is provided between the branch of the branch wiring and the inspection terminal.   A plurality of inspection terminals are provided, and a control signal for controlling opening and closing of the switch is supplied through a control line connected to an inspection terminal different from the inspection terminal to which the branch wiring is connected. The circuit device according to claim 1.   The circuit device according to claim 2, wherein the switch is opened as a result of the inspection terminal connected to the control line being opened.   The circuit device according to claim 1, wherein an integrated circuit chip is connected to the connection terminal. The circuit is a data line driving circuit,
A scanning line driving circuit;
A pixel circuit arranged in a matrix in a region for displaying an image, and supplied with output signals from the data line driving circuit and the scanning line driving circuit;
5. The circuit device according to claim 1, comprising:   An electronic apparatus comprising the circuit device according to claim 1. On the board,
Circuit,
A connection terminal at a position away from the circuit;
Signal wiring connecting the circuit and the connection terminal;
An inspection terminal;
A branch wiring connecting the branch of the signal wiring and the inspection terminal;
A switch provided between the branch and the inspection terminal;
A circuit device inspection method comprising:
A. Providing a signal for closing the switch to a control line for controlling opening and closing of the switch;
B. B. providing an input signal of the circuit to the branch wiring through the inspection terminal, or detecting an output signal of the circuit from the branch wiring; A method for inspecting a circuit device, comprising the step of opening the inspection terminal. The circuit device includes a plurality of the inspection terminals, and the control line of the switch is connected to an inspection terminal different from the inspection terminal to which the branch wiring is connected,
The step A is a step of providing a signal for closing the switch via the another inspection terminal,
The step C is a step of opening both an inspection terminal to which the branch wiring is connected and another inspection terminal to which the control line of the switch is connected. Item 8. A method for inspecting a circuit device according to Item 7.   9. The circuit device according to claim 7, wherein the circuit device is a circuit device for driving a display element, and the step AC is performed before the display element is formed in the circuit device. Inspection method.   10. The connection terminal according to claim 7, wherein the connection terminal is a connection terminal for attaching an integrated circuit chip to the substrate, and the step AC is performed before attaching the integrated circuit chip. 2. A method for inspecting a circuit device according to item 1.

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