JPH086047A - Inspection method of active matrix substrate - Google Patents

Abstract

PURPOSE:To inspect the shorting defect between adjacent data signal lines within a display part, the shorting defect between adjacent pixel electrodes and the shorting defect between the pixel electrodes and the adjacent data signal lines prior to liquid crystal injection without using a costly inspection system and intricate measuring system. CONSTITUTION:Inspection signals are inputted to input terminals 18b, 18c of video signal input lines 16b, 16c to operate a data signal driving circuit 11. The potential or current generated at the input terminal 18a of the video signal input line 16a is then measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting an active matrix substrate used in a liquid crystal display device or the like.

[0002]

2. Description of the Related Art Conventionally, as a driving method of a display device such as a liquid crystal display device, an EL display device and a plasma display device, a switching element is connected to each of pixel electrodes arranged in a matrix and selectively driven. An active matrix driving method for forming a display pattern is known. This active matrix drive system is capable of high-contrast display, and has been put to practical use in, for example, liquid crystal televisions, word processors, and terminal display devices of computers. Further, as a switching element for selectively driving the pixel electrode, a TFT (thin film transistor) element, a MIM (metal-insulator-metal) element, an M
OS (metal-oxide-semiconductor) transistor elements, diodes, varistors, etc. are generally known.

An active matrix substrate used in an active matrix drive type display device has a display section in which pixel electrodes and switching elements for selectively driving the pixel electrodes are formed, and a drive circuit for driving the display section. Conventionally, this drive circuit is provided by bonding an integrated circuit of single crystal silicon or the like to an active matrix substrate on which a display unit is formed by a method such as tab bonding or COG (chip on glass) bonding. However, in recent years, research on a driver monolithic active matrix substrate in which a display section and a drive circuit are simultaneously formed on the same substrate has been actively conducted. A normal active matrix substrate requires a large number of expensive driver LSIs,
In the driver monolithic type active matrix substrate, the driver circuit is formed at the same time as the switching element formed in the display portion, so that the cost of the display device can be reduced. Further, since all peripheral functions are integrated in an area of only a few mm around the display unit, the entire module can be made compact and the mounting process can be simplified. The merits of this are great.

FIG. 1 shows an example of a liquid crystal display device using a driver monolithic active matrix substrate. The active matrix substrate of this liquid crystal display device is
The plurality of scanning signal lines 6 and the plurality of data signal lines 5 are formed in a state of intersecting each other, and the TFT 7 as a switching element is provided in the vicinity of the intersection of the scanning signal lines and the data signal lines.
Then, the pixel capacitor 9 and the pixel electrode connected to the drain electrode of the TFT 7 are formed to form a display section.

A scan signal drive circuit (gate drive circuit) 12 for outputting a scan signal for controlling the drive of the TFT 7 to the scan signal line 6 and a data signal for output to the data signal line 5 are provided around the display portion on the substrate. And a data signal drive circuit 11 that operates. The data signal drive circuit 11 includes a shift register 13 and a video signal input terminal 1 to which a data signal is input.
Video signal input line 16 including 8a, 18b, and 18c, respectively
a, 16b, 16c, and an analog switch 14 interposed between the video signal input line and the data signal line 5 and controlled by the output from the shift register 13.

The counter substrate on which the counter electrode is formed is made to face the active matrix substrate having such a structure, liquid crystal is sealed between the active matrix substrate and the counter substrate, and the liquid crystal is sealed between the pixel electrode and the counter electrode. Pixels 8 functioning as electric capacitors are formed in parallel with the pixel capacitors 9. Further, one terminal of each pixel capacitor 9 and one terminal of the additional capacitor 15 of the data signal line 5 are connected to the pixel capacitor ground terminal 17 through the pixel capacitor common wiring 10 and grounded together with the counter electrode on the counter substrate. .

In general, the active matrix substrate has a low non-defective rate, resulting in a high manufacturing cost. In the case of a driver monolithic type active matrix substrate, the non-defective product ratio of the display unit is lower than that of the drive circuit unit, and improvement of the non-defective product ratio of the display unit is a major issue. In order to improve the non-defective rate, it is essential to develop a defect inspection method. In particular, it is an important technique to perform inspection before liquid crystal injection to sort good products and defective products, because it leads to cost reduction in subsequent steps and early feedback to the manufacturing process.

As a method of inspecting the display section before injecting liquid crystal, for example, in Japanese Patent Laid-Open No. 158056/1993, a signal output from a video signal input terminal by inputting a DC or square wave signal into a pixel capacitance ground terminal. Discloses a method of detecting a pixel defect such as a short circuit of pixel capacitance. Further, Japanese Laid-Open Patent Publication No. 57-38498 discloses a method of inspecting even a point defect by writing a signal to an additional capacitance of each pixel and examining a holding characteristic. Further, Japanese Patent Application Laid-Open No. 2-72392 discloses a method of inspecting a short circuit defect between a scanning signal line and a data signal line by inputting a scanning signal and measuring a current flowing through each data bus line. ing.

[0009]

The method of inspecting the above-mentioned active matrix substrate before injecting the liquid crystal has the following problems.

According to the method disclosed in Japanese Unexamined Patent Publication No. 5-158056, the short circuit defect of the pixel capacitance of each pixel and the open / short circuit defect of the TFT of the display section can be inspected, but the short circuit defect between the adjacent data signal lines. Also, it is not possible to inspect for short circuit defects between adjacent pixel electrodes. These defect modes are important as inspection items because they occur at high frequencies due to abnormalities during patterning of the thin film layers forming each of them, and it is a serious problem that these defect modes cannot be detected. Further, a driving method of inverting the polarity of the corresponding video signal between adjacent data signal lines is effective in suppressing flicker. However, when this driving method is used, a short circuit defect between adjacent data signal lines and If there is a short circuit defect between adjacent pixel electrodes, the video signal is canceled there. Therefore, in normally white display, a plurality of signal lines or a plurality of pixels are defective in bright lines or bright spots, which is fatal as a display device. JP-A-57-3
In the method disclosed in Japanese Patent No. 8498, it is possible in principle to inspect all defect modes including a short circuit defect between adjacent data signal lines and a short circuit defect between adjacent pixel electrodes. However, in the driver monolithic active matrix substrate, the parasitic capacitance of the video signal line is very large on the order of several tens of pF, and the detected signal is as small as several mV.
N needs to be improved. Further, there is a problem that the inspection system becomes very expensive because it is necessary to analyze a huge amount of measurement data at high speed. JP-A-2-72392
In the method disclosed in the publication, it is necessary to probe each data bus line to measure the current value, which makes the measurement system very complicated. Further, in a high-definition liquid crystal display device having a bus line pitch of several tens of mm, there is a problem that probing itself becomes difficult.

The present invention has been made to solve the above-mentioned problems of the prior art, and short-circuits between adjacent data signal lines in the display section without using an expensive inspection system or a complicated measurement system. Defects, short circuit defects between adjacent pixel electrodes,
Another object of the present invention is to provide an inspection method for an active matrix substrate, which can inspect a short circuit defect between a pixel electrode and a data signal line adjacent to the pixel electrode. Another object of the present invention is to provide a method of inspecting an active matrix substrate capable of inspecting a short circuit defect in pixel capacitance.

[0012]

According to an active matrix substrate inspection method of the present invention, a plurality of scanning signal lines and a plurality of data signal lines are formed so as to intersect with each other, and the scanning signal lines and the data signal lines intersect with each other. A scanning signal drive circuit for outputting a scanning signal for controlling the switching element to the scanning signal line on a substrate on which a switching element, a pixel electrode connected to the switching element, and a pixel capacitance are formed in a matrix shape in the vicinity of the area; A data signal drive circuit for outputting a data signal to the data signal line is formed, and the data signal drive circuit is formed with a plurality of video signal input lines each having a video signal input terminal to which a data signal is input. In the method for inspecting an active matrix substrate, an inspection signal is input to a part of a plurality of video signal input terminals to form a data signal drive circuit. And short circuit defect between data signal lines, short circuit defect between pixel electrodes or between the pixel electrode and the data signal line adjacent to the pixel electrode by measuring the potential or current generated in another video signal input terminal. Short circuit defects are detected, thereby achieving the above objective.

In one embodiment, all of the switching elements are turned off for inspection, and in another embodiment,
All the switching elements are turned on and the inspection is performed.

In one embodiment, the inspection is performed by driving the scanning signal circuit together with the data signal driving circuit.

According to the active matrix substrate inspection method of the present invention, a plurality of scanning signal lines and a plurality of data signal lines are formed so as to intersect with each other, and a switching element and a switching element are provided near the intersections of the scanning signal lines and the data signal lines. A scanning signal drive circuit that outputs a scanning signal for controlling the switching element to the scanning signal line and a data signal line on the substrate on which pixel electrodes and pixel capacitors connected to the switching element are formed in a matrix. A data signal drive circuit for outputting a data signal is formed, and the data signal drive circuit is provided with a plurality of video signal input lines each having a video signal input terminal to which a data signal is input. An inspection method, in which an inspection signal is input to a part of a plurality of video signal input terminals to operate a scanning signal drive circuit and another image is input. Since the short circuit defect between the data signal lines, the short circuit defect between the pixel electrodes or the short circuit defect between the pixel electrode and the data signal line adjacent to the pixel electrode is detected by measuring the potential or the current generated at the signal input terminal. Therefore, the above object is achieved.

In one embodiment, the inspection is performed by turning on all analog switches provided in the data signal drive circuit and interposed between the video signal input line and the data signal line.

According to the active matrix substrate inspection method of the present invention, a plurality of scanning signal lines and a plurality of data signal lines are formed in a state where they intersect with each other, and a switching element and a switching element are provided near the intersections of the scanning signal lines and the data signal lines. A scanning signal drive circuit that outputs a scanning signal for controlling the switching element to the scanning signal line and a data signal line on the substrate on which pixel electrodes and pixel capacitors connected to the switching element are formed in a matrix. A data signal driving circuit for outputting a data signal is formed, and the data signal driving circuit is formed with a video signal input line having a video signal input terminal for inputting a data signal. Therefore, the inspection signal is input to the video signal input terminal through a resistor to drive the data signal drive circuit or the scan signal drive circuit. It is, and detects the short defect of the pixel capacitor by measuring a potential or current generated in the video signal input terminal, the above-mentioned object can be achieved by it.

According to the active matrix substrate inspection method of the present invention, a plurality of scanning signal lines and a plurality of data signal lines are formed in a state where they intersect with each other, and a switching element and a switching element are provided near the intersections of the scanning signal lines and the data signal lines. A scanning signal drive circuit that outputs a scanning signal for controlling the switching element to the scanning signal line and a data signal line on the substrate on which pixel electrodes and pixel capacitors connected to the switching element are formed in a matrix. A data signal drive circuit for outputting a data signal is formed, and the data signal drive circuit is provided with a plurality of video signal input lines each having a video signal input terminal to which a data signal is input. An inspection method, in which an inspection signal is input to a part of a plurality of video signal input terminals through resistors to drive a data signal drive circuit or Short defect of the pixel capacitor by scanning signal No. driving circuit is operated to measure the potential or current generated in the video signal input terminal and other video signal input terminal,
Since the short circuit defect between the data signal lines, the short circuit defect between the pixel electrodes, or the short circuit defect between the pixel electrode and the data signal line adjacent to the pixel electrode is detected, the above object is achieved thereby.

In one embodiment, the inspection is performed by setting the pulse width of the sampling pulse in the data signal drive circuit to twice the sampling period or more.

In one embodiment, the inspection is performed by setting the drive frequency at the time of inspection to be equal to or lower than the drive frequency at the time of actual display and at least 1/100 of the drive frequency at the time of actual display.

In one embodiment, a test is conducted by connecting a resistance of 1 kΩ or more and 1 MΩ or less to the video signal input terminal.

[0022]

The inspection signal is input to a part of the plurality of video signal input terminals, and the potential or current of the other video signal input terminals is measured. When the data signal drive circuit is operated with all of the switching elements formed in the display section in the on state or all in the off state, the data signal line corresponding to the pixel causing the short circuit defect corresponds to the defect at the selected timing. The signal is output. When the scanning signal drive circuit is operated by turning on all the analog switches provided in the data signal drive circuit between the video signal input line and the data signal line, the scanning corresponding to the pixel causing the short circuit defect is performed. A signal corresponding to the defect is output at the timing when the signal line is selected. When the data signal drive circuit and the scan signal drive circuit are simultaneously operated, the scan signal line corresponding to the pixel having the short circuit defect is selected, and the data signal line corresponding to the pixel is defective at the selected timing. A signal corresponding to is output. Therefore, a short circuit defect between the data signal lines,
A short circuit defect between pixel electrodes or a short circuit defect between a pixel electrode and a data signal line adjacent to this pixel electrode can be detected.

When a test signal is input to a video signal input terminal (if a plurality of them are formed) via a resistor and the drop in the current or potential generated at the video signal input terminal is measured, the pixel capacitance is short-circuited. A defect, a short circuit defect between data signal lines, a short circuit defect between pixel electrodes, or a short circuit defect between a pixel electrode and a data signal line adjacent to this pixel electrode can be detected.

When the pulse width of the sampling pulse in the data signal drive circuit is set to be twice the sampling period or more and the inspection is performed, the output signal level becomes high when the pulses corresponding to the short circuit defect overlap. Therefore, the S / N can be improved.

The S / N can be improved by setting the drive frequencies of the data signal drive circuit and the scan signal drive circuit to be equal to or lower than the drive frequency for actual display.
Also, the measurement time can be shortened by setting it to 1/100 or more of the driving frequency for actual display.

If a resistance of 1 kΩ or more and 1 MΩ or less is connected to the video signal input terminal as a waveform shaping resistance for inspection, the S / N can be improved without making it difficult to specify the address.

[0027]

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

(Embodiment 1) In this embodiment, a method of inspecting a short circuit defect 21 between adjacent data signal lines on the driver monolithic active matrix substrate shown in FIG. 1 will be described. In this figure, the pixels 8 and the counter substrate 8b formed by enclosing the liquid crystal are not provided at the time of inspection of the active matrix substrate.

In this active matrix substrate, the data signal drive circuit 11 has three video signal input lines 16a and 16a.
b, 16c are formed in parallel, and control signals X1, X2, X3, X output from the shift register 13 are output.
Are connected to the corresponding data signal lines 5 via the analog switches 14 controlled by. The video signal input terminals 18 of the video signal input lines 16b and 16c
GN input to the pixel capacitance ground terminal 17 at b and 18c
A DC bias of +5 V with respect to D is applied as an inspection signal. On the other hand, the video signal input terminal 18 of the video signal line 16a
A is grounded via a waveform shaping resistor R, and a probe is connected to monitor the potential. Further, the scanning signal drive circuit 12 is adapted to output a signal of a non-selection level to all the scanning signal lines 6, whereby all the TFTs 7 in the display section are turned off. This is because, for example, in the case where the scan signal drive circuit 12 is provided with a shift register, the start signal has a DC level corresponding to non-selection.
It can be easily realized by using a signal. When all the TFTs 7 are turned off in this way, even if there is a short-circuit defect 22 between adjacent pixel electrodes or a short-circuit defect 23 between the pixel electrode and an adjacent data signal line, signals corresponding to these are not output. . Therefore, the detected defect can be specified as the short-circuit defect 21 between the adjacent data signal lines. When the data signal drive circuit 11 is operated in this state, a bias corresponding to the input inspection signal is written in the data signal lines D2, D3, D5, D6, ... Corresponding to the video signal input lines 16b, 16c. . On the other hand, since the video signal input line 16a is grounded via the resistor R, it becomes GND in the normal case, and GND is written in the corresponding data signal lines D1, D4, ....
When there is a short circuit defect 21 between the data signal lines D3 and D4, when the bias corresponding to the inspection signal is written to the data signal line D3 by the control signal X3, the same bias is written to the data signal line D4 at the same time. Therefore, when the analog switch 14 corresponding to the control signal X4 is opened, the charges held in the data signal line D4 are input to the video signal input line 16a. Therefore, the video signal input line 1
When the potential of 6a is monitored, the corresponding signal is observed.

Control signals (X1, X2, X3, X4, ...
An example of the drive timing of () and the probe waveform connected to the video signal input line 16a is shown in FIG. Also,
As shown in FIG. 2B, the control signals X1, X2, X3,
The pulse width of X4, ... May be twice or more the sampling period. In the case of the driving method of FIG. 2B, X3
And X4 overlap, a DC path is formed between the video signal input lines 16a and 16b through the short-circuit defect 21. Therefore, there is an advantage that the output signal level is increased and the S / N is improved as compared with the case of the driving method of FIG.

In this embodiment, the data signal drive circuit 11 was driven at a frequency half that used in an actual display device, and a waveform shaping resistor of R = 100 kΩ was connected to the video signal input line 16a. As a result, the output signal level of the probe waveform can be set to the order of several hundred mV, and an S that is sufficient to detect the signal and specify the address of the data signal line having a short circuit defect using an inexpensive system.
/ N could be obtained.

In the above embodiment, the inspection is performed by monitoring the potential, but the present invention is not limited to this, and it goes without saying that the defect inspection can be performed even if the current is measured. This also applies to each of the following embodiments.

(Embodiment 2) In this embodiment, a short circuit defect 21 between adjacent data signal lines and a short circuit defect 22 between adjacent pixel electrodes on the driver monolithic active matrix substrate shown in FIG. 1 are inspected. The method will be described.

In this inspection, the scanning signal drive circuit 12 is operated together with the data signal drive circuit 11, and the rest is the same as in the first embodiment. When the output waveforms of the probe are examined by operating both drive circuits in this way, the timing when the scanning signal line corresponding to the pixel having the short circuit defect is selected and the data signal line corresponding to the pixel is selected Then, a signal similar to that of the first embodiment is output. Thereby, the short-circuit defect 21 between the adjacent data signal lines and the short-circuit defect 22 between the adjacent pixel electrodes can be inspected.

In order to output a signal corresponding to a defect using the inspection method of this embodiment, it is necessary to charge the additional capacitance 15 of the data signal line 5 and the parasitic capacitance of the signal line via the TFT 7 of the display section. There is. For this reason, if driving is performed at the drive frequency used in an actual display device and measurement is performed, charging becomes insufficient, and a signal corresponding to a defect cannot be sufficiently detected. Moreover, since several hundred thousand pixels are usually formed in the display unit, it is not easy to check the signal level at high speed for several hundred thousand addresses.
Therefore, it is desirable to lower the drive frequency for measurement.

The short-circuit defect 21 inspected in this embodiment.
As to which of the two defects, 22 and 22, the short-circuit defect 21 is specified based on the first embodiment, it is possible to specify only the short-circuit defect 22.

In this embodiment, the short-circuit defect 21 between the adjacent data signal lines and the short-circuit defect between the adjacent pixel electrodes 22 are inspected. However, the short circuit between the pixel electrode and the data signal line adjacent to the pixel electrode is short-circuited. The defect 23 can also be inspected by the same principle. Specifically, the inspection of the short-circuit defect 23 is performed as follows. In FIG. 1, when the short-circuit defect 23 exists, the video signal input terminal 1
The probe is connected to 8b, and the inspection signal is input to the video signal input terminal 18c. Then, when the corresponding scanning signal line 6 is at the selection level, the data signal lines D3 to D2 are charged through the short circuit defect 23 and the TFT 7, and the same signal as in the short circuit defect 22 between the pixel electrodes is detected.

(Embodiment 3) In this embodiment, a short circuit defect 22 between adjacent pixel electrodes on the driver monolithic active matrix substrate shown in FIG. 1 or a pixel electrode and a data signal line adjacent to this pixel electrode are formed. A method for inspecting the short-circuit defect 23 between the two will be described.

In this embodiment, all the TFTs 7 in the display section are turned on so that the scanning signal drive circuit 12 outputs a signal of a selection level to all the scanning signal lines 6, and an inspection is performed. This can be easily realized by setting the start signal to the level at the pulse of the start pulse when the scan signal drive circuit 12 is provided with a shift register, for example. When all the TFTs 7 are turned on in this way, there is no problem that the impedance of the TFT 7 in the display section becomes rate-determining as in the inspection method of the second embodiment.

When the data signal drive circuit is operated in this state and the output waveform of the probe is examined, it is similar to the case of the first embodiment at the timing when the data signal line corresponding to the pixel having the short circuit defect is selected. Signal is observed, which results in an inspection. However, in this inspection method, the short-circuit defect 21 between the adjacent data signal lines and the short-circuit defect 22 between the adjacent pixel electrodes are inspected. When the short-circuit defect 21 between the adjacent data signal lines occurs, it can be detected by the method of the first embodiment. Therefore, if the short circuit defect 21 is detected by the inspection method of the third embodiment without being detected by the inspection method of the first embodiment, It can be specified as a short circuit defect 22 between adjacent pixel electrodes or a short circuit defect 23 between a pixel electrode and a data signal line adjacent to this pixel electrode. Due to the above, the short-circuit defect 22 or 23
Is specified in the X direction.

Next, a method of identifying the Y-direction address of the short-circuit defect 22 between the pixel electrodes will be described. Here, the control signals X1, X2, ...
.. are all set to the selection level and all the analog switches 14 are turned on.

When the scanning signal drive circuit 12 is operated in this state and the output waveform of the probe is examined, the scanning signal line 6 corresponding to the pixel causing the short circuit defect is selected at the same timing as in the first embodiment. Such a signal can be observed to identify the address in the Y direction. In this case, the impedance of the TFT 7 of the display section is rate-determining, but S / N could be improved by setting the waveform shaping resistance R to 10 kΩ or more. Further, when specifying the address in the Y direction, the number of addresses to be checked is small and about 1000 at most, so that the measurement is easier than in the second embodiment. In this embodiment, about 1 when used in an actual display device.
The data signal driving circuit 11 and the scanning signal driving circuit 12 are driven at a frequency of / 5, and the waveform shaping resistor R = 100 kΩ
Was measured.

In the inspection method of this embodiment, when there is one pixel electrode short-circuit defect between the video signal input lines 16a and 16b, the two-dimensional address can be specified. Cannot completely specify each two-dimensional address. However, in the actual manufacturing process, if the number of defects is small, it is necessary to identify the address because it becomes symmetrical such as repair, but if there are many defects, it cannot be considered as a good product even by repair, so the number of defects is Knowing can be a sufficiently practical test. If the Y address is specified by this method, the second embodiment
Since it is necessary to observe only the signal of the Y address portion in, the efficient inspection is possible by combining these methods.

In the first to third embodiments described above, the active matrix substrate in which one control signal output from the shift register of the data driving circuit as shown in FIG. 1 corresponds to one data signal line is inspected. However, the present invention is not limited to this, and it is possible to inspect an active matrix substrate having a structure in which a plurality of video signal input lines are formed. For example, as shown in FIG. 3, a plurality of video signal input lines 16a, 16b, 16c, 16d each having a video signal input terminal 18a, 18b, 18c, 18d are formed, and a plurality of analog switches 14 make one sampling signal. Similarly, it is possible to detect a short-circuit defect between adjacent data signal lines, a short-circuit defect between adjacent pixel electrodes, and a short-circuit defect between a pixel electrode and an adjacent data signal line for an active matrix substrate controlled by. it can. still,
In FIG. 3, the pixel 8 is not provided during the inspection of the active matrix substrate.

In the above embodiment, it is not possible to determine whether the detected short-circuit defect is 22 or 23, but since the address is known, a method such as observing the portion with a microscope is used. It is possible to know which one is a short circuit defect.

(Embodiment 4) In this embodiment, a method for inspecting a short circuit defect of the pixel capacitor 9 on the driver monolithic active matrix substrate shown in FIG. 4 will be described. In this figure, the pixel 8 is not provided during the inspection of the active matrix substrate.

In this active matrix substrate, the data signal driving circuit 11 is provided with video signal input terminals 18a and 1a, respectively.
Four video signal input lines 1 having 8b, 18c and 18d
6a, 16b, 16c, 16d are formed in parallel, and via an analog switch 14 controlled by one control signal X output from the shift register 13 to a plurality of (four in the illustrated example) video signal input lines. , The video signal input lines and the corresponding data signal lines 5 are connected.

The inspection of this substrate in this embodiment is performed as follows. The inspection signal is input to the video signal input terminal 18d of the video signal input line 16d via a resistor. On the other hand, the video signal input terminals 18a, 18b and 18c of the video signal lines 16a, 16b and 16c are grounded similarly to the wiring connected to the pixel capacitance ground terminal. Further, the scanning signal driving circuit 12 is adapted to output a signal of a selection level to all the scanning signal lines 6, whereby all the TFTs 7 in the display section are turned on.

In this state, the data signal drive circuit 11 is operated. At this time, the data signal line 5 corresponding to the short circuit defect
When the analog switch 14 connected to is opened, a short circuit defect, a DC path through the TFT 7 and the analog switch 14 is formed, and a current flows. When this current or the potential drop caused thereby is measured by the probe connected to the video signal input line 16d, the short-circuit defect can be detected, whereby the X-direction address of the short-circuit defect can be specified. Also, regarding the address in the Y direction,
It can be specified by the same method as in Example 3.

However, in the inspection method of this embodiment, a short circuit defect 21 between adjacent data signal lines, a short circuit defect 22 between adjacent pixel electrodes, and a pixel electrode and this pixel electrode are generated. Even when the short circuit defect 23 occurs between the adjacent data signal line, it is detected similarly to the short circuit defect of the pixel capacitance. Therefore, the type of defect can be specified by combining the inspection method of this embodiment with the inspection method of Embodiments 1 to 3.

Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications can be made.

In the above-mentioned first to fourth embodiments, as shown in FIG. 2B, when the inspection is performed by setting the pulse width of the sampling pulse in the data signal drive circuit to be twice the sampling period or more, it is possible to detect a short circuit defect. When the pulses to be applied are overlapped, the output signal level is increased and the S / N can be improved.

The driving frequency of the data signal driving circuit and the scanning signal driving circuit is set to ⅕ of the driving frequency at the time of actual display, but other frequencies may be used. S /
From the viewpoint of N, it is desirable to make it equal to or lower than the drive frequency at the time of actual display, and from the perspective of measurement time, it is desirable to make it to 1/100 or more of the drive frequency at the time of actual display.

Although a resistance of 10 kΩ or 100 kΩ is connected as a waveform shaping resistance to the video signal input terminal, other resistance may be used. However, if a resistor with a resistance of more than 1 MΩ is used, the discharge time constant becomes large, making it difficult to specify the address. If a resistor of less than 1 kΩ is used, the impedance of the resistor is low, and the height of the output pulse becomes small, which is not desirable. .

Although a DC bias of about 5 V was applied as the inspection signal, other inspection signals may be applied.

When a signal due to a defect is detected, whether the potential is mainly measured or the current is mainly measured may be determined according to the S / N and the sensitivity of the detection system and is connected in series to the probe. The resistance can be set to meet the appropriate conditions.

[0057]

As is apparent from the above description, according to the present invention, a short circuit defect between adjacent data signal lines in a display section which could not be detected without using an expensive device or a complicated measuring system up to now. , A short circuit defect between adjacent pixel electrodes and a short circuit defect between the pixel electrode and a data signal line adjacent to this pixel electrode can be easily inspected before injecting liquid crystal, and further, a short circuit defect of a pixel capacitance is also inspected. can do. Therefore, it is possible to improve the non-defective product ratio of the active matrix substrate and to sort the non-defective product and non-defective product at the time of inspection to reduce the manufacturing cost in the post-process. In addition, when a defective portion is specified and the data is used as feedback information to the previous process, it is possible to prevent the occurrence of the defect. Furthermore, since it is possible to detect a short-circuit defect between adjacent data signal lines and a short-circuit defect between adjacent pixel electrodes, it is possible to detect a short circuit defect between adjacent data signal lines by using a driving method that inverts the polarity of the corresponding video signal between adjacent data signal lines. In a liquid crystal display device of mari-white display, it is possible to prevent a plurality of signal lines or a plurality of pixels from becoming a bright line or a bright point defect, and it is effective in suppressing flicker.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a liquid crystal display device for explaining an inspection method of an active matrix substrate which is an embodiment of the present invention.

FIG. 2 is a conceptual diagram showing drive timings and signals corresponding to defects in an active matrix substrate inspection method according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of a liquid crystal display device for explaining an inspection method of an active matrix substrate which is another embodiment of the present invention.

FIG. 4 is a configuration diagram of a liquid crystal display device for explaining an inspection method of an active matrix substrate which is another embodiment of the present invention.

[Explanation of symbols]

 5 data signal line 6 scanning signal line 7 TFT 8 pixel 9 pixel capacitance 10 pixel capacitance common wiring 11 data signal drive circuit 12 scanning signal drive circuit (gate drive circuit) 13 shift register 14 analog switch 15 additional capacitance 16a, 16b, 16c, 16d Video signal input line 17 Pixel capacitance ground terminal 18a, 18b, 18c, 18d Video signal input terminal 21 Short circuit defect 22 Short circuit defect 23 Short circuit defect

Claims (6)

[Claims] 1. A plurality of scanning signal lines and a plurality of data signal lines are formed in a state of intersecting each other, and a switching element and a pixel electrode connected to the switching element near an intersection of the scanning signal line and the data signal line. A scan signal drive circuit that outputs a scan signal for controlling a switching element to the scan signal line and a data signal drive circuit that outputs a data signal to the data signal line on a substrate on which the pixel capacitances are formed in a matrix. And a plurality of video signal input lines each having a video signal input terminal to which a data signal is input are formed in the data signal drive circuit. Input a test signal to a part of the signal input terminal to operate the data signal drive circuit and measure the potential or current generated in other video signal input terminals. Method of inspecting an active matrix substrate for detecting short circuit defects between the data signal lines, the short-circuit defect between the data signal line adjacent to the short-circuit defective or the pixel electrode and the pixel electrodes between the pixel electrodes by. 2. The method for inspecting an active matrix substrate according to claim 1, wherein the inspection is performed by driving a scanning signal circuit together with the data signal driving circuit. 3. A plurality of scanning signal lines and a plurality of data signal lines are formed in a state of intersecting each other, and a switching element and a pixel electrode connected to the switching element near an intersection of the scanning signal line and the data signal line. A scan signal drive circuit that outputs a scan signal for controlling a switching element to the scan signal line and a data signal drive circuit that outputs a data signal to the data signal line on a substrate on which the pixel capacitances are formed in a matrix. And a plurality of video signal input lines each having a video signal input terminal to which a data signal is input are formed in the data signal drive circuit. Input the inspection signal to a part of the signal input terminal to operate the scanning signal drive circuit and measure the potential or current generated in other video signal input terminals. Method of inspecting an active matrix substrate for detecting short circuit defects between the data signal lines, the short-circuit defect between the data signal line adjacent to the short-circuit defective or the pixel electrode and the pixel electrodes between the pixel electrodes by the. 4. The data signal driving circuit is provided in the circuit,
4. The method for inspecting an active matrix substrate according to claim 3, wherein all analog switches interposed between the video signal input line and the data signal line are turned on to perform the inspection. 5. A plurality of scanning signal lines and a plurality of data signal lines are formed in a state of intersecting each other, and a switching element and a pixel electrode connected to the switching element near an intersection of the scanning signal line and the data signal line. A scan signal drive circuit that outputs a scan signal for controlling a switching element to the scan signal line and a data signal drive circuit that outputs a data signal to the data signal line on a substrate on which the pixel capacitances are formed in a matrix. And a video signal input line having a video signal input terminal to which a data signal is input is formed in the data signal drive circuit. A test signal is input through a resistor to operate the data signal drive circuit or the scan signal drive circuit, and the potential generated at the video signal input terminal or Method of inspecting an active matrix substrate that detects a short defect of the pixel capacitor by measuring the flow. 6. A plurality of scanning signal lines and a plurality of data signal lines are formed in a state of intersecting each other, and a switching element and a pixel electrode connected to the switching element in the vicinity of an intersection of the scanning signal line and the data signal line. A scan signal drive circuit that outputs a scan signal for controlling a switching element to the scan signal line and a data signal drive circuit that outputs a data signal to the data signal line on a substrate on which the pixel capacitances are formed in a matrix. And a plurality of video signal input lines each having a video signal input terminal to which a data signal is input are formed in the data signal drive circuit. An inspection signal is input to a part of the signal input terminal via a resistor to operate the data signal driving circuit or the scanning signal driving circuit, and the video signal input terminal By measuring the potential or current generated in the other video signal input terminal, the pixel capacitance short circuit defect, the data signal line short circuit defect, the pixel electrode short circuit defect or the pixel electrode and the data signal line adjacent to the pixel electrode. A method of inspecting an active matrix substrate for detecting a short circuit defect between the substrate and the substrate.