JP3393231B2 - Inspection method and inspection device for liquid crystal display panel - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection method and an inspection apparatus for inspecting a liquid crystal display panel for a specific structural defect. The liquid crystal display panel to be inspected is, for example, a so-called Cs-on provided with an auxiliary capacitance (Cs) for stabilizing the charge retention operation of the pixel electrode.
An active matrix substrate having a -common structure is used.

[0002]

2. Description of the Related Art Although not shown, a liquid crystal display panel usually has a structure in which two substrates are arranged in parallel and opposed to each other with a space of a required interval, and liquid crystal is interposed in this space.
One of the two substrates is called an active matrix substrate, and the other substrate is called a counter substrate. In some cases, RGB or YMC three color filters may be provided on the counter substrate.

For example, FIG. 5 schematically shows a general circuit configuration of a liquid crystal display panel using an active matrix substrate having a Cs-on-common structure.

FIG. 5 is a circuit diagram showing the structure of a general liquid crystal display panel. In the figure, 1 is a gate bus line as a plurality of scanning lines arranged in the row direction, 2 is a source bus line as a plurality of signal lines arranged in the column direction, 3 is a matrix of both bus lines 1 and 2. And a plurality of pixels provided corresponding to a rectangular area formed by the intersection of. The pixel 3 mainly includes a pixel electrode 4 and a thin film transistor (TF).
T) and other switching elements 5, but the auxiliary capacitor 6 is also attached here.

Reference numeral 7 is an auxiliary capacitance bus line wired in parallel with the gate bus line 1, 8 is a common counter electrode, 1a is a lead terminal of the gate bus line 1, and 2a is a lead terminal of the source bus line 2. The gate electrode of the switching element 5 is connected to the gate bus line 1, the source electrode of the switching element 5 is connected to the source bus line 2, and the drain electrode of the switching element 5 is connected to the pixel electrode 4. The auxiliary capacitance 6 is connected to the drain electrode of the switching element 5 and the auxiliary capacitance bus line 7.

The gate bus line 1, the source bus line 2, the pixel 3, and the auxiliary capacitance bus line 7 are provided on the active matrix substrate side, and the counter electrode 8 is provided on the counter substrate side.

In such a liquid crystal display panel, structural defects (described below, etc.) caused by the manufacturing process may occur. The structural defect is a disconnection between the pixel electrode 4 and the switching element 5, the structural defect is a short circuit between the pixel electrode 4 and the auxiliary capacitance bus line 7, and the structural defect is between the pixel electrode 4 and the counter electrode 8. Is a short circuit.

By the way, in the case where the liquid crystal display panel is in the normally white mode which is the current mainstream, and when the above structure defect is normal and normal, a liquid crystal of each pixel 3 transmits light when a normal drive signal is supplied. Not displayed, that is, black dots are displayed. On the other hand, when any one of the above structural defects is present, the appropriate voltage cannot be applied to the pixel electrode 4, so that the liquid crystal in the region corresponding to the pixel 3 having the structural defect is not driven and light is emitted. In other words, it remains in the transparent state, that is, the bright spot is displayed. That is, the display quality is degraded.

For this reason, liquid crystal display panels are inspected for display defects after manufacturing. In this inspection, the display state of each pixel 3 is checked by actually turning on the light.

[0010]

In the above-described conventional lighting inspection, the normal pixel 3 and the pixel 3 having the structural defect can be distinguished, but the structural defects 1 to 3 cannot be distinguished. If the liquid crystal display panel having these structural defects (1) to (3) is treated as a defective product as it is, the production cost is inevitably increased because the yield is remarkably reduced.

Since structural defects among the above structural defects can be repaired, this repair can contribute to the improvement of yield. Therefore, at least it is necessary to identify structural defects. By the way,
As the correction of the structural defect, for example, Japanese Patent Laid-Open No. 6-18383
Examples thereof include those disclosed in JP-A-60 and JP-A-3-209422.

Therefore, conventionally, after finding all the pixels 3 in which the lighting failure has occurred by performing the above-described lighting inspection, the inspector visually checks the pixels 3 in which the lighting failure has occurred individually by using a microscope. By inspecting, the type of structural defect is recognized. However, it is pointed out that such a method is wasteful because it takes a lot of time and labor to inspect one liquid crystal display panel.

On the other hand, the applicant of the present invention has disclosed that Japanese Patent Laid-Open No. 6-
As disclosed in Japanese Patent No. 82836, it is proposed that the presence or absence of a structural defect be inspected and the found structural defect portion be appropriately corrected. The inspection of this structural defect is, in short, inputting various inspection signals to the gate bus line, the source bus line, and the counter electrode, and checking the display states (black spots, bright spots) at the time of inputting each inspection signal, The types of structural defects are distinguished by the combination of the display states. In such a conventional example, although it is possible to distinguish the structural defects 1 to 3, it is pointed out that the inspection content is troublesome and the circuit configuration becomes complicated as an inspection device.

Therefore, according to the present invention, among various structural defects occurring in a liquid crystal display panel, a pixel having at least a repairable structural defect, that is, a pixel having a structural defect such as a short circuit between a pixel electrode and a counter electrode, can be simply and quickly. The purpose is to provide an inspection method that can be recognized by In addition, the present invention provides a simple and quick structure of a pixel having at least a repairable structural defect, that is, a pixel having a structural defect of a short circuit between a pixel electrode and a counter electrode, among various structural defects occurring in a liquid crystal display panel. The purpose is to provide an inspection device that can be recognized by the public.

[0015]

The inspection method according to claim 1 is
The two substrates are arranged parallel to each other with a space of a required space therebetween, and the liquid crystal is interposed in the space, and the scanning lines and the signal lines are arranged in a matrix on one substrate, and both substrates are arranged. A pixel electrode, a switching element and an auxiliary capacitor are provided respectively corresponding to a rectangular area generated by the intersection of lines, and a common counter electrode facing all the pixel electrodes is provided on the other substrate of a liquid crystal display panel. An inspection method, wherein a signal for driving a switching element is generated on a scanning line and a signal line, and a potential difference sufficient for liquid crystal driving is generated between a counter electrode and an auxiliary capacitor between a counter electrode and a pixel electrode. By supplying different signals to each other and checking the display state of each pixel at that time, the pixel having the structural defect of short circuit between the pixel electrode and the counter electrode is recognized. That.

According to a second aspect of the present invention, there is provided an inspection method in which two substrates are arranged in parallel to each other with a space of a required interval therebetween and liquid crystal is interposed in the space, and one substrate is provided with a scanning line and a signal line. In addition to being arranged in a matrix, pixel electrodes, switching elements and auxiliary capacitors are respectively provided in correspondence with the rectangular area generated by the intersection of both lines,
A method for inspecting a liquid crystal display panel, wherein a common counter electrode facing all the pixel electrodes is provided on the other substrate, and a normal liquid crystal drive is performed for a scanning line, a signal line, a counter electrode and an auxiliary capacitor. Supply the first drive signal to be used,
A first inspection step for recognizing a normal pixel by checking the display state of each pixel at that time, and a second drive signal in which the supply voltage to the counter electrode and the auxiliary capacitance of the first drive signal is set to the large side And a display state of each pixel at that time is compared with a display state in the first inspection process to recognize a pixel having a structural defect such as a disconnection between the switching element and the pixel electrode. In the inspection step, the supply voltage to the counter electrode of the first drive signal is set to the high side, and the third drive signal having the supply voltage to the auxiliary capacitance as the ground voltage is supplied, and the display state of each pixel at that time By comparing the display state in the second inspection process with the display state in the second inspection process, a structural defect of a pixel having a structural defect of a short circuit between the pixel electrode and the auxiliary capacitor and a short circuit between the pixel electrode and the counter electrode is found. Recognizing a pixel standing respectively third
And an inspection process.

An inspection apparatus according to a third aspect of the present invention has a structure in which two substrates are opposed to each other in parallel with a space having a required space therebetween, and liquid crystal is interposed in the space, and a scanning line and a signal line are provided on one substrate. In addition to being arranged in a matrix, pixel electrodes, switching elements and auxiliary capacitors are respectively provided in correspondence with the rectangular area generated by the intersection of both lines,
A testing device for a liquid crystal display panel, wherein a common counter electrode facing all the pixel electrodes is provided on the other substrate, which is connected to a scanning line, a signal line, a counter electrode and an auxiliary capacitor of the liquid crystal display panel. Multiple inspection terminals,
A signal for driving a switching element is generated on the scanning line and the signal line through each inspection terminal, and a potential difference sufficient for liquid crystal driving is generated between the counter electrode and the auxiliary capacitor between the counter electrode and the pixel electrode. And signal output means for supplying different signals to each other.

An inspection apparatus according to a fourth aspect of the present invention has a structure in which two substrates are opposed to each other in parallel with a space having a required space therebetween, and liquid crystal is interposed in the space, and a scanning line and a signal line are provided on one substrate. In addition to being arranged in a matrix, pixel electrodes, switching elements and auxiliary capacitors are respectively provided in correspondence with the rectangular area generated by the intersection of both lines,
A testing device for a liquid crystal display panel, wherein a common counter electrode facing all the pixel electrodes is provided on the other substrate, which is connected to a scanning line, a signal line, a counter electrode and an auxiliary capacitor of the liquid crystal display panel. Multiple inspection terminals,
A signal for driving a switching element is generated on the scanning line and the signal line through each inspection terminal, and a potential difference sufficient for liquid crystal driving is generated between the counter electrode and the auxiliary capacitor between the counter electrode and the pixel electrode. , A signal output means for supplying different signals to each other, an image pickup means for picking up a display state of the liquid crystal display panel, and a structural defect of a short circuit between the pixel electrode and the counter electrode based on the display image picked up by the image pickup means. Recognizing means for recognizing the existing pixel.

According to a fifth aspect of the present invention, the inspection device has a structure in which two substrates are arranged in parallel and opposite to each other with a space of a required distance therebetween, and liquid crystal is interposed in the space, and one substrate is provided with a scanning line and a signal line. In addition to being arranged in a matrix, pixel electrodes, switching elements and auxiliary capacitors are respectively provided in correspondence with the rectangular area generated by the intersection of both lines,
A testing device for a liquid crystal display panel, wherein a common counter electrode facing all the pixel electrodes is provided on the other substrate, which is connected to a scanning line, a signal line, a counter electrode and an auxiliary capacitor of the liquid crystal display panel. Multiple inspection terminals,
Of the first drive signal used for normal liquid crystal drive and the second drive signal and the first drive signal for which the supply voltage for the counter electrode and the auxiliary capacitance is set to the large side for each inspection terminal And a signal output means for selectively outputting any of the third drive signals in which the supply voltage to the counter electrode is set to the high side and the supply voltage to the auxiliary capacitance is set to the ground voltage.

An inspection apparatus according to a sixth aspect of the present invention has a structure in which two substrates are arranged in parallel and opposed to each other with a space of a required interval therebetween, and liquid crystal is interposed in the space, and one substrate is provided with a scanning line and a signal line. In addition to being arranged in a matrix, pixel electrodes, switching elements and auxiliary capacitors are respectively provided in correspondence with the rectangular area generated by the intersection of both lines,
A testing device for a liquid crystal display panel, wherein a common counter electrode facing all the pixel electrodes is provided on the other substrate, which is connected to a scanning line, a signal line, a counter electrode and an auxiliary capacitor of the liquid crystal display panel. Multiple inspection terminals,
Of the first drive signal used for normal liquid crystal drive and the second drive signal and the first drive signal for which the supply voltage for the counter electrode and the auxiliary capacitance is set to the large side for each inspection terminal A signal output means for setting the supply voltage to the counter electrode to the high side and selectively outputting one of the third drive signals in which the supply voltage to the auxiliary capacitance is the ground voltage, and the first to third drive signals, respectively. Based on the image pickup means for picking up each display state of the liquid crystal display panel and each display image picked up by the image pickup means, there is a normal pixel and a structural defect such as a disconnection between the switching element and the pixel electrode. A pixel and a pixel having a structural defect such as a short circuit between the pixel electrode and the auxiliary capacitance;
And a recognition unit that recognizes each pixel having a structural defect such as a short circuit between the pixel electrode and the counter electrode.

According to the seventh aspect of the present invention, in the management means of the fourth or sixth aspect, when the pixel having the structural defect is recognized, the position of the pixel is recognized.

In the above invention, in short, Cs-on-
The present invention relates to an inspection method and an inspection apparatus for a liquid crystal display panel using an active matrix substrate having a common structure.

Further, according to the first aspect, only the pixel having a structural defect such as a short circuit between the pixel electrode and the counter electrode can be recognized. That is, in the case of claim 1, with respect to a pixel having a structural defect such as a short circuit between the pixel electrode and the counter electrode, the display state is reversed from the display state of the normal pixel, and the display state between the switching element and the pixel electrode is changed. A pixel having a structural defect such as disconnection and a pixel having a structural defect such as a short circuit between the pixel electrode and the auxiliary capacitance bus line have the same display state as that of a normal pixel. Therefore, if there is a pixel with a different display state, it can be considered that there is a structural defect of a short circuit between the pixel electrode and the counter electrode for that pixel.

According to the second aspect of the present invention, the inspection is performed in three stages, so that the normal pixel, the pixel having a structural defect such as a short circuit between the pixel electrode and the counter electrode, the switching element and the pixel electrode. Pixels having a structural defect of disconnection between pixels and pixels having a structural defect of short circuit between the pixel electrode and the auxiliary capacitance bus line can be identified. That is, in the first inspection step of the second aspect, with respect to the pixels having various structural defects, the display state is reversed from the display state of the normal pixels, so that only the normal pixels can be identified. In the second inspection step of claim 2, a pixel having a structural defect such as a disconnection between the switching element and the pixel electrode is in the same display state as a normal pixel, while the pixel electrode and the auxiliary capacitance bus line are in the same display state. Regarding a pixel having a structural defect of a short circuit between the pixel electrode and a pixel having a structural defect of a short circuit between the pixel electrode and the counter electrode, the display state is reversed from the display state of the normal pixel described above. Therefore, by comparing the display state in the second inspection process with the display state in the first inspection process, it is possible to recognize the presence or absence of a pixel having a structural defect such as a disconnection between the switching element and the pixel electrode. it can. In the third inspection step, a normal pixel is displayed for a pixel having a structural defect such as a short circuit between the pixel electrode and the auxiliary capacitance bus line and a pixel having a structural defect such as a disconnection between the switching element and the pixel electrode. The display state is the same as that of the state, and a pixel having a structural defect such as a short circuit between the pixel electrode and the counter electrode has a display state that is the reverse of the display state of the normal pixel. Therefore, by comparing the display state in the third inspection step with the display state in the second inspection step, a pixel in which a structural defect such as a short circuit between the pixel electrode and the auxiliary capacitance bus line exists, The presence or absence of a pixel having a structural defect such as a short circuit between the electrode and the counter electrode can be recognized. In this way, the presence or absence of various structural defects and their discrimination can be performed by the first to third inspection steps.

In claim 3, the operator visually recognizes the display state of the liquid crystal display panel to be inspected, but in claim 4, the display state of the liquid crystal display panel to be inspected is imaged by the image pickup means. Then, the management means recognizes the presence or absence of a pixel having a specific structural defect.

In claim 5, the operator visually recognizes the display state of the liquid crystal display panel to be inspected. In claim 6, the display state of the liquid crystal display panel to be inspected is imaged by the image pickup means. Then, the management means recognizes a normal pixel and the presence or absence of a pixel having various structural defects.

According to the seventh aspect, the position of the pixel having the structural defect can be recognized, which is convenient when the structural defect is corrected.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION The details of the present invention will be described below with reference to the embodiments shown in FIGS. 1 to 3
FIG. 1 is a circuit configuration diagram of an inspection device, FIG. 2 is a signal waveform diagram showing each inspection signal output from the inspection device, and FIG. 3 is an inspection situation of a liquid crystal display panel. FIG.

In this embodiment, the liquid crystal display panel A to be inspected uses an active matrix substrate having a Cs-on-Common structure of TFT type, and has a TN (twisted nematic) mode and a normally white mode. I shall. The circuit configuration of the liquid crystal display panel A is, for example, as shown in FIG. 5 used in the description of the conventional example.

In this inspection, the liquid crystal display panel A may have structural defects (1) to (3) caused by the manufacturing process. Therefore, the pixel 3 having these structural defects (3) is inspected. B is used for recognition. The structural defect is a disconnection between the pixel electrode 4 and the switching element 5, the structural defect is a short circuit between the pixel electrode 4 and the auxiliary capacitance bus line 7, and the structural defect is between the pixel electrode 4 and the counter electrode 8. Is a short circuit between.

As shown in FIG. 1, the inspection apparatus B includes first to third terminals as connection terminals for the liquid crystal display panel A to be inspected.
Fourth inspection terminals 21a to 21d and each inspection terminal 21
a signal output means 22 for outputting the signals S1 to S4 to a to 21d, and a designating means 23 for designating a combination pattern of the signals S1 to S4 output from the signal output means 22 according to the following three types of inspection processes. An image pickup unit 24 for picking up an image of the display state of the liquid crystal display panel A to be inspected and a display unit 25 for displaying an image picked up by the image pickup unit 24 are included.

The above-mentioned three types of inspection processes include a first inspection process for recognizing a normal pixel 3, a second inspection process for recognizing a pixel 3 having a structural defect, and a pixel having a structural defect. 3 and a pixel 3 having a structural defect.

The first inspection terminal 21a is connected to the lead terminal 1a of the gate bus line 1 of the liquid crystal display panel A, and the second inspection terminal 21b is connected to the source bus line 2 of the liquid crystal display panel A.
The drawing terminal 2a and the third inspection terminal 21d are drawn to the drawing terminal (not shown) of the counter electrode 8 of the liquid crystal display panel A, and the fourth checking terminal 21c is drawn to the auxiliary capacitance bus line 7 of the liquid crystal display panel A. Each is connected to a terminal (not shown).

The signal output means 22 is a reference signal generation circuit 3
1 and a frequency dividing circuit 32 for frequency-dividing the output signal from the reference signal generating circuit 31, and a signal S for on / off control to which the output signal from the frequency dividing circuit 32 is input and given to the gate bus line 1.
1 and a second signal generation circuit 3 for generating an ON / OFF control signal S2 to which the output signal from the frequency dividing circuit 32 is input and which is applied to the source bus line 2.
4 and the output signal from the frequency dividing circuit 32 are input to the counter electrode 8
A third signal generating circuit 35 for generating a signal S3 to be supplied to the circuit and varying the voltage value of the signal S3 within a required range;
A GND terminal 36 that outputs a signal S4 having a potential and a changeover switch 37 that connects either the output terminal of the third signal generating circuit 35 or the GND terminal 36 to the fourth inspection terminal 21d are provided.

The designating means 23 switches the changeover switch 37 in accordance with the first to third inspection steps, and the
The voltage value of the signal S3 generated from the signal generation circuit 35 is designated. In addition, in the first inspection process, as shown in FIG.
As shown in (a), the combination pattern of the signals S1 to S4 is "S1-S2-S3-S3", and the signal S3 = D.
C-1 [V]. The combination pattern of the signals in FIG. 2A is exactly the same as that of the normal liquid crystal driving.
In the second inspection step, as shown in FIG.
The combination pattern from S4 to S4 is "S1-S2-S3-S".
3 ”, and the signal S3 = DC15 [V]. In the third inspection step, as shown in FIG. 2C, the combination pattern of the signals S1 to S4 is set to "S1-S2-S3-S4", and the voltage value of the signal S3 is the same as that in the second inspection step, that is, DC.
Set to 15 [V].

Next, a method of inspecting the liquid crystal display panel A will be described.

First, as a preparation for the inspection, the liquid crystal display panel A to be inspected is set in a state substantially the same as the actual use condition. That is, as shown in FIG. 3, the polarizing plates 41 and 42 are arranged above and below the liquid crystal display panel A, respectively.
The backlight 43 is arranged below the polarizing plate 41 on the active matrix substrate side of the liquid crystal display panel A, and the image pickup means 24 of the inspection device B is arranged above the polarizing plate 42 on the counter substrate side of the liquid crystal display panel A. . Then, in the liquid crystal display panel A, the lead-out terminal 1a of the gate bus line 1, the lead-out terminal 2a of the source bus line 2, the lead-out terminal of the counter electrode 8, and the lead-out terminal of the auxiliary capacitance bus line 7 are used for the inspection of the inspection device B. The terminals 21a to 21d are connected to each other.

After that, the first to third inspection steps are performed. Here, in each inspection step, the display state of the liquid crystal display panel A is displayed on the display means 25 so that the operator can visually check it.

In the first inspection process, the inspection device B is used as shown in FIG.
The signal shown in (a), that is, "S1-S2-S3-S3" is generated and supplied to the liquid crystal display panel A. However, the signal S
3 is DC-1 [V]. As a result, the display state of each pixel 3 of the liquid crystal display panel A becomes as shown in Table 1.

[0040]

[Table 1]

In this case, in the normal pixel 3, since the switching element 5 is turned on and the voltage is normally applied between the pixel electrode 4 and the counter electrode 8, the pixel electrode 4 and the counter electrode 8 are connected. A required potential difference is generated between them, resulting in a state where no light is transmitted, that is, a black dot display. However, in the pixel 3 in which any one of structural defects (1) to (3) has occurred, a required potential difference does not occur between the pixel electrode 4 and the counter electrode 8, and therefore, the state of transmitting light, that is, the bright spot display is maintained. Therefore, Table 1
Normal pixels 3 based on the display of bright or black dots shown in
And the pixel 3 in which any one of the structural defects 1 to 3 has occurred can be distinguished, and the normal pixel 3 can be recognized.

In the second inspection step, the inspection apparatus B is used as shown in FIG.
The signal shown in (b), that is, "S1-S2-S3-S3" is supplied to the liquid crystal display panel A. However, the signal S3 is DC 15 [V]. Thereby, the liquid crystal display panel A
The display state of each pixel 3 is as shown in Table 2.

[0043]

[Table 2]

In this case, the black dots are displayed in the normal pixel 3 similarly to the above, but since the signal S3 is set to DC 15 [V], the pixel 3 having the structural defect, that is, the switching element 5 is not turned on. But the pixel electrode 4
Therefore, a required potential difference is generated between the counter electrode 8 and the counter electrode 8, and as a result, black dots are displayed as in the normal case.
In addition, a pixel 3 in which any one of structural defects has occurred
Then, since a required potential difference does not occur between the pixel electrode 4 and the counter electrode 8, the bright spot display is maintained. Therefore, based on the display of bright spots or black spots shown in Table 2, a normal pixel 3 and a pixel 3 having a structural defect, a structural defect,
Can be distinguished from the pixel 3 in which Then, by comparing the display result of the second inspection process with the display result of the first inspection process, it becomes possible to recognize the pixel 3 having the structural defect.

In the third inspection step, the inspection apparatus B is used as shown in FIG.
The signal shown in (c), that is, "S1-S2-S3-S4" is supplied to the liquid crystal display panel A. At this time, the signal S
3 is the same DC15 [V] as in the second inspection process, and the signal S4 is the GND potential. In short, different signals are applied to the auxiliary capacitance bus line 7 and the counter electrode 8 instead of the normal liquid crystal driving. As a result, the display state of each pixel 3 of the liquid crystal display panel A becomes as shown in Table 3.

[0046]

[Table 3]

In this case, in the pixel 3 having the structural defect, a potential difference is generated between the pixel electrode 4 and the counter electrode 8.
For example, in the case of the liquid crystal display panel A, when the liquid crystal capacity: the auxiliary capacity = 2: 1 is set, the potential V1 of the pixel electrode 4 is V1 = 1.
0 [V], the potential V2 of the counter electrode 8 = 15 [V], and the potential V3 of the auxiliary capacitance bus line V3 = 0 [V], and the liquid crystal of the pixel 3 having the structural defect emits light as in the normal pixel 3. It is in a non-transparent state, that is, a black dot is displayed. In the pixel 3 having a structural defect, a potential difference is generated between the pixel electrode 4 and the counter electrode 8, so V1 = V3 = 0 [V], V2 =
The voltage becomes 15 [V], and the liquid crystal of the pixel 3 having a structural defect does not transmit light, that is, the black dot display, as in the normal pixel 3. Further, in the pixel 3 having the structural defect, since no potential difference is generated between the pixel electrode 4 and the counter electrode 8, V1 = V2 = V3 = 0 [V], and the liquid crystal of the pixel 3 having the structural defect is generated. , A state of transmitting light, that is, a bright spot display. Therefore, based on the display of bright spots or black spots shown in Table 3, normal pixels 3 and structural defects,
It is possible to distinguish the pixel 3 in which the defect exists and the pixel 3 in which the structural defect exists. Then, by comparing the display result of the third inspection process with the display result of the second inspection process, it becomes possible to recognize the pixel 3 in which the structural defect exists.

As described above, by comprehensively judging the respective results of the first to third inspection steps, the presence or absence of structural defects can be distinguished. Although the display state in each inspection process is visually checked by the display means 25, when the operator visually checks the liquid crystal display panel A with a microscope and identifies the types of structural defects 1 to 3, as in the conventional case. In comparison, it is much easier and can shorten the inspection time.

Then, based on the above inspection result, the inspection liquid crystal display panel A may be moved to a process for correcting it or to be disposed of as a defective product. Therefore, the total time required to complete the inspection and the correction of the structural defect can be shortened, and the manufacturing cost of the liquid crystal display panel A can be reduced.

FIG. 4 is a circuit configuration diagram of an inspection apparatus according to another embodiment of the present invention. In this embodiment, the presence / absence of the structural defect of the liquid crystal display panel A and its distinction can be automatically performed without the operator's visual observation.

The inspection apparatus B includes the first to fourth inspection terminals 2 as connection terminals for the liquid crystal display panel A to be inspected.
1a to 21d, signal output means 22 for outputting signals S1 to S4 to the inspection terminals 21a to 21d, and combination patterns of signals S1 to S4 output from the signal output means 22 for the first to third inspection processing. According to the designation means, an image pickup means 24 for picking up the display state of the liquid crystal display panel A to be inspected, a display means 25 for displaying the image picked up by the image pickup means 24, and a display image of the display means 25. And a management unit 26 for recognizing the position of the pixel 3 in which the structural defect is present and determining the presence or absence of the structural defect.

In this inspection apparatus B, the first inspection in the above embodiment is performed.
~ By sequentially performing the third inspection step for each required time, capturing the display image of the liquid crystal display panel A of each inspection result, and performing a comprehensive judgment by performing the comparison as described in each inspection step in the above-mentioned embodiment The presence / absence of the structural defect-is distinguished and the position of the pixel 3 in which the structural defect-is present is recognized.

As in this embodiment, if the inspection apparatus B automatically determines whether or not the liquid crystal display panel A has a structural defect (1) to be distinguished from the other, the above-mentioned operation is performed artificially based on the display of the display means 25. The inspection efficiency can be improved compared to the example. Moreover, based on the inspection result, it becomes possible to move to the processing for correcting the inspected liquid crystal display panel A or to the processing for disposing as a defective product by the automatic transport unit. It is possible to automate the process up to the correction of the structural defect corresponding to the process. Such automation can further contribute to the reduction in the manufacturing cost of the liquid crystal display panel A.

The present invention is not limited to the above embodiment, and various applications and modifications can be considered.

(1) In the above-described embodiment, all the pixels 3 having the structural defects 3 to 3 of the liquid crystal display panel A can be identified, but only the structural defects may be recognized. In this case, only the third inspection step in the above embodiment needs to be performed.

(2) Liquid crystal display panel A to be inspected
The type of is not particularly limited. That is, the liquid crystal display panel A may be in any form such as twisted nematic mode, electric field control birefringence type, guest-host mode, and other various modes. The switching element of the active matrix substrate of the liquid crystal display panel A is a three-terminal type of a reverse staggered thin film transistor (TFT) using amorphous silicon, a thin film transistor using polysilicon or single crystal silicon, a staggered structure, a planar structure. It does not matter whether it is a two-terminal type such as a varistor or a diode.

[0057]

According to the first and third aspects of the present invention, the operator does not have to perform the troublesome and time-consuming work of visually observing the liquid crystal display panel with a microscope to identify the type of structural defect as in the conventional case. Among various structural defects that occur in the liquid crystal display panel, at least a structural defect that can be corrected, that is, a short circuit between the pixel electrode and the counter electrode can be easily and quickly recognized, and the inspection efficiency can be significantly improved compared to the conventional one. Like Therefore, it is possible to shorten the total time required to complete the inspection and, if necessary, the correction of the structural defect, which can contribute to the reduction of the manufacturing cost of the liquid crystal display panel. In Claims 2 and 5, not only the structural defect recognized in Claims 1 and 3, but also a pixel having a structural defect called disconnection between the switching element and the pixel electrode and between the pixel electrode and the auxiliary capacitance bus line are present. A pixel having a structural defect such as a short circuit can be recognized, and more effective inspection can be performed.

According to the fourth and sixth aspects, the structural defect is recognized automatically not by the operator's visual recognition, but the inspection efficiency can be further improved.

According to the present invention, not only the presence or absence of the structural defect can be recognized but also the position of the pixel in which the structural defect exists can be recognized. The automated processing can be performed.

As described above, according to the present invention, the inspection can be carried out efficiently and the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of an inspection device according to an embodiment of the present invention.

FIG. 2 is a signal waveform diagram showing an inspection signal output from the inspection device of FIG.

FIG. 3 is an explanatory view showing an inspection situation of the embodiment.

FIG. 4 is a circuit configuration diagram of an inspection device according to another embodiment of the present invention.

FIG. 5 is a circuit diagram showing a configuration of a general liquid crystal display panel.

[Explanation of symbols]

A liquid crystal display panel 1 gate bus line 2 Source bus line 3 pixels 4 pixel electrodes 5 switching elements 6 auxiliary capacity 7 auxiliary capacity bus line 8 Counter electrode B inspection device 21a to 21d First to fourth inspection terminals 22 Signal output means 23 Designation method 24 Imaging means 25 Display means 26 Management means 31 Reference signal generating circuit of signal output means 32 Frequency dividing circuit of signal output means 33 First signal generation circuit of signal output means 34 Second signal generation circuit of signal output means 35 Third signal generation circuit of signal output means 36 GND terminal of signal output means 37 Signal output means changeover switch 41,42 Polarizing plate 43 Backlight

Claims (7)

(57) [Claims] 1. A structure in which two substrates are opposed to each other in parallel with a space having a required space therebetween and liquid crystal is interposed in the space, and scanning lines and signal lines are arranged in a matrix on one substrate. In addition, pixel electrodes, switching elements and auxiliary capacitors are provided respectively corresponding to the rectangular area generated by the intersection of both lines, and the other substrate is provided with a common counter electrode facing all the pixel electrodes. A method for inspecting a liquid crystal display panel, wherein a signal for driving a switching element is applied to a scanning line and a signal line, and a potential difference sufficient for driving a liquid crystal between the counter electrode and the auxiliary capacitor is applied between the counter electrode and the pixel electrode. Existence of structural defects such as a short circuit between the pixel electrode and the counter electrode by supplying different signals to each other and checking the display state of each pixel at that time. Recognizes pixels that, the inspection method of the liquid crystal display panel, characterized in that. 2. A structure in which two substrates are arranged in parallel and opposite to each other with a space of a required space therebetween, and liquid crystal is interposed in the space, and scanning lines and signal lines are arranged in a matrix on one substrate. In addition, pixel electrodes, switching elements and auxiliary capacitors are provided respectively corresponding to the rectangular area generated by the intersection of both lines, and the other substrate is provided with a common counter electrode facing all the pixel electrodes. A method for inspecting a liquid crystal display panel, comprising:
A first inspection step of recognizing a normal pixel by supplying a first driving signal used for normal liquid crystal driving and checking a display state of each pixel at that time, and a counter electrode of the first driving signal By supplying the second drive signal in which the supply voltage for the auxiliary capacitance is set to the high side,
A second inspection step for recognizing a pixel having a structural defect such as a disconnection between the switching element and the pixel electrode by comparing the display state of each pixel at that time with the display state in the first inspection process; Of the first drive signal, the supply voltage to the counter electrode is set to the high side, and the third drive signal in which the supply voltage to the auxiliary capacitance is set to the ground voltage is supplied, and the display state of each pixel at that time and the second inspection process A pixel having a structural defect of a short circuit between the pixel electrode and the auxiliary capacitance and a pixel having a structural defect of a short circuit between the pixel electrode and the counter electrode by recognizing the display state in FIG. A method for inspecting a liquid crystal display panel, comprising: 3. A structure in which two substrates are opposed to each other in parallel with a space having a required space therebetween, and liquid crystal is interposed in the space, and scanning lines and signal lines are arranged in a matrix on one substrate. In addition, pixel electrodes, switching elements and auxiliary capacitors are provided respectively corresponding to the rectangular area generated by the intersection of both lines, and the other substrate is provided with a common counter electrode facing all the pixel electrodes. A liquid crystal display panel inspecting device, comprising: a plurality of inspection terminals connected to a scanning line, a signal line, a counter electrode and an auxiliary capacitance of the liquid crystal display panel, and a scanning line and a scanning line via each inspection terminal. A signal for driving the switching element is supplied to the signal line, and a signal different from each other is generated between the counter electrode and the auxiliary capacitor so that a potential difference sufficient for driving the liquid crystal is generated between the counter electrode and the pixel electrode. The inspection device of a liquid crystal display panel, which comprises a signal output means for supplying, respectively, the. 4. A structure in which two substrates are opposed to each other in parallel with a space having a required space therebetween and liquid crystal is interposed in the space, and scanning lines and signal lines are arranged in a matrix on one substrate. In addition, pixel electrodes, switching elements and auxiliary capacitors are provided respectively corresponding to the rectangular area generated by the intersection of both lines, and the other substrate is provided with a common counter electrode facing all the pixel electrodes. A liquid crystal display panel inspecting device, comprising: a plurality of inspection terminals connected to a scanning line, a signal line, a counter electrode and an auxiliary capacitance of the liquid crystal display panel, and a scanning line and a scanning line via each inspection terminal. A signal for driving the switching element is supplied to the signal line, and a signal different from each other is generated between the counter electrode and the auxiliary capacitor so that a potential difference sufficient for driving the liquid crystal is generated between the counter electrode and the pixel electrode. A signal output means for supplying the liquid crystal display panel, an image pickup means for picking up a display state of the liquid crystal display panel, and a pixel having a structural defect such as a short circuit between the pixel electrode and the counter electrode on the basis of the display image picked up by the image pickup means. An inspection device for a liquid crystal display panel, comprising: management means for recognizing the presence or absence of. 5. A structure in which two substrates are arranged in parallel and opposite to each other with a space of a required interval therebetween, and liquid crystal is interposed in the space, and scanning lines and signal lines are arranged in a matrix on one substrate. In addition, pixel electrodes, switching elements and auxiliary capacitors are provided respectively corresponding to the rectangular area generated by the intersection of both lines, and the other substrate is provided with a common counter electrode facing all the pixel electrodes. An inspection device for a liquid crystal display panel, comprising: a plurality of inspection terminals connected to the scanning lines, signal lines, counter electrodes and auxiliary capacitors of the liquid crystal display panel; The first drive signal used for driving the liquid crystal, the second drive signal in which the supply voltage to the counter electrode and the auxiliary capacitor of the first drive signal is set to the large side, and the supply voltage to the counter electrode of the first drive signal. The containing, and signal output means for outputting selectively one of a supply voltage third driving signal and a ground voltage for the auxiliary capacitor and sets the larger side, the inspection device of a liquid crystal display panel, characterized in that. 6. A structure in which two substrates are opposed to each other in parallel with a space having a required space therebetween and liquid crystal is interposed in the space, and scanning lines and signal lines are arranged in a matrix on one substrate. In addition, pixel electrodes, switching elements and auxiliary capacitors are provided respectively corresponding to the rectangular area generated by the intersection of both lines, and the other substrate is provided with a common counter electrode facing all the pixel electrodes. An inspection device for a liquid crystal display panel, comprising: a plurality of inspection terminals connected to the scanning lines, signal lines, counter electrodes and auxiliary capacitors of the liquid crystal display panel; The first drive signal used for driving the liquid crystal, the second drive signal in which the supply voltage to the counter electrode and the auxiliary capacitor of the first drive signal is set to the large side, and the supply voltage to the counter electrode of the first drive signal. And a liquid crystal display panel which is driven by each of the first to third drive signals, and which selectively outputs one of the third drive signals whose ground voltage is the supply voltage to the auxiliary capacitance. Image pickup means for picking up each display state of, a normal pixel, a pixel having a structural defect of disconnection between the switching element and the pixel electrode, and a pixel electrode based on each display image picked up by the image pickup means. And a storage capacitor having a structural defect such as a short circuit between the storage capacitor and a storage capacitor, and a pixel having a structural defect such as a short circuit between the pixel electrode and the counter electrode. Liquid crystal display panel inspection device. 7. The inspection apparatus according to claim 4, wherein when the management unit recognizes a pixel having a structural defect, the management unit recognizes the position of the pixel.