JP2002311405A - Method and apparatus for inspecting liquid crystal panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inspecting method and an inspection apparatus which can detect and specify a short-circuited portion between signal wiring and common wiring in a liquid crystal panel. SOLUTION: In the inspecting method of the liquid crystal panel, by which scanning wiring and the common wiring are arranged in parallel on one substrate, the signal wiring is arranged orthogonally crossed with these wirings, switching elements to be arranged in a matrix shape and pixel electrodes to be connected to the signal wiring via the switching elements are provided at a crossed part of the scanning wiring and the signal wiring and an electric field approximately in parallel with the substrate surface is applied between a common electrode and pixel electrodes to be connected to the common wiring to operate a liquid crystal, voltage 1 to be applied to the common wiring is set so that the voltage difference between the voltage 1 to be applied to the common wiring and average voltage 3 to be applied to the signal wiring is made larger than the voltage difference in the case of normal display so that vertical and horizontal line defects with the short-circuited portion as an intersection are displayed in the case of detection of the short-circuited portion between the signal wiring and the common wiring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal panel suitable as a display for AV equipment and OA equipment, and more particularly to a method and an apparatus for inspecting active matrix type liquid crystal panels for defects.

[0002]

2. Description of the Related Art At present, display panels using a liquid crystal have been applied to various fields such as a viewfinder of a video camera, a pocket TV, an information display terminal such as a high-definition projection TV, a personal computer, and a word processor. Active development and commercialization. In particular, an active matrix type TN (Twisted Nematic) liquid crystal display panel using a thin film transistor (TFT) as a switching element has a great feature that high contrast is maintained even when a large-capacity display is performed. The development and commercialization of notebook PCs and large and large-capacity full-color monitors are very popular.

In such an active matrix type liquid crystal display panel, there is a TN (Twisted Nematic) method as a liquid crystal display mode widely used. In the TN mode, a panel having a structure in which liquid crystal molecules are twisted by 90 ° between a pair of electrode substrates sandwiching a liquid crystal layer is sandwiched between two polarizing plates. The two polarizing plates are arranged so that their polarization axes are orthogonal to each other, and one of the polarizing plates is parallel or perpendicular to the long axis direction of the liquid crystal molecules in contact with one substrate. When no voltage is applied between the two substrates, that is, when no voltage is applied to the liquid crystal panel, white display is performed. However, when a voltage is applied in the vertical direction to the liquid crystal panel, the light transmittance gradually decreases and black display is performed. Becomes Such display characteristics are obtained because, when a voltage is applied to the liquid crystal panel, the liquid crystal molecules are arranged in the direction of the electric field while unwinding the twisted structure. Is changed, and the light transmittance is modulated. However, even in the same molecular arrangement state, the polarization state of the transmitted light changes depending on the incident direction of the light incident on the liquid crystal panel, so that the light transmittance differs according to the incident direction. That is, the characteristics of the liquid crystal panel have a viewing angle dependency. Such a viewing angle dependency affects the image quality of the liquid crystal panel because the inclination of the viewpoint with respect to the main viewing angle direction (the major axis direction of the liquid crystal molecules in the intermediate layer of the liquid crystal layer) causes a luminance reversal phenomenon.

In order to improve the viewing angle dependency, instead of applying an electric field in the vertical direction of the substrate as in the TN type liquid crystal display system, the direction of the electric field applied to the liquid crystal is changed in a direction substantially parallel to the substrate. IPS (In-Plane Switching) system has been devised and disclosed in, for example, Japanese Patent Publication No. 63-21907 and Japanese Patent Application Laid-Open No. Hei 6-160878.

FIG. 6 shows a configuration of an active matrix array substrate of a general IPS type liquid crystal display panel. As shown in the figure, a plurality of scanning wirings 11 and signal wirings 14 are formed so as to be orthogonal to each other. The scanning wirings 11 are connected to electrode pads 19, and the signal wirings 14 are connected to electrode pads 20, respectively. A switching element 16 is provided at each intersection of the scanning wiring 11 and the signal wiring 14. The switching element 16 is usually a thin film transistor, and its gate is connected to the scanning wiring 11, its source is connected to the signal wiring 13, and its drain is connected to the pixel electrode 15. Further, usually, in order to protect the switching element 16 from static electricity which may be generated in a process of manufacturing a panel, outside the electrode pad, between each signal wiring 14,
In addition, a power supply wiring (not shown) that connects between the scanning wirings 11 is provided.

The two adjacent scanning lines 11 and the two adjacent scanning lines 11
A plurality of (for example, two) pixel electrodes 15 are formed in one pixel region surrounded by one signal wiring 14. A plurality of (for example, three) common electrodes 12 are formed between the signal wiring 14 and the pixel electrode 15 and between the adjacent pixel electrodes 15. The storage capacitor 17 is a pixel electrode 1
5 and above the scanning wiring 11. The common electrode 12 is connected to a common line 13 formed between two adjacent scanning lines 11. Each common wiring 13 is connected to another common wiring via a contact hole 19,
They are collectively connected to the common wiring electrode pad 18. Note that an insulating layer (not shown) exists at the intersection between the scanning wiring 11 and the common wiring 13 and the signal wiring 14.

[0007]

Generally, when fabricating an active matrix array substrate, a short circuit may occur between the electrode wirings due to a defect at the time of patterning. Therefore, usually after the completion of the array substrate, an inspection for confirming the existence of such a defect is performed. This panel inspection
Generally, after removing the power supply wiring for the countermeasures against static electricity, a probe (probe) is applied to each of the electrode pads for each of the signal wiring and the scanning wiring to apply a predetermined voltage to perform an electrical inspection. And directly identify the shorted wiring. Here, the predetermined voltage used for inspection is, for example, as shown in FIG.
The voltage applied to each wiring at the time of normal display as shown in FIG. That is, in FIG. 7, the DC voltage 1
(7 V), and a rectangular wave AC voltage 3 (5 V, 11 V) having a center voltage 3 (8 V) is applied to the signal wiring. If a short-circuit portion can be identified at the time of this inspection, it can be repaired, and a reduction in the manufacturing yield of the array substrate can be prevented.

In the case of a normal TN type active matrix array substrate, only the signal wiring and the scanning wiring are provided on the substrate. Therefore, a short circuit between the wirings occurs only between the signal wiring and the scanning wiring. On the other hand, I
In the case of the active matrix array substrate of the PS system, the common wiring 13 is provided in addition to the signal wiring 14 and the scanning wiring 11. Therefore, a short circuit occurs not only between the signal wiring 14 and the scanning wiring 11 but also between the signal wiring 14 and the common wiring. 13 and also between the scanning wiring 11 and the common wiring 13.

In the case of the above substrate configuration, the scanning wiring 1
1 and the common wiring 13 are formed by patterning in the same photolithography step through the same film forming process, so that a short-circuit portion between the wirings can be found by visual inspection. However, the short between the signal wiring 14 and the common wiring 13 is the same as between the signal wiring 14 and the scanning wiring 11.
The short-circuited portion cannot be visually identified because it is caused by interlayer insulation failure such as the presence of a pinhole in the insulating layer. Further, the common electrode 12 of the related art has a configuration in which the common electrode 12 is collectively connected to all the pixels as described above. If an interlayer short-circuit occurs between the common wiring 13 and the signal wiring 14, the above-described inspection method can be used. Although it was possible to determine the presence or absence of an interlayer short-circuit, it was not possible to identify the short-circuited portion. That is, in the conventional method,
When there is a short-circuited portion, a line defect was observed in the direction along the signal line 14, but no line defect was observed in the direction along the common line 13. It could not be determined whether the pixel was defective.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to provide an inspection method for an active matrix type liquid crystal panel, which can identify a short-circuit point between a common wiring and a signal wiring. It is to provide a method and an inspection device.

[0011]

A first liquid crystal panel inspection method according to the present invention has a pair of substrates, on one of which a scanning wiring and a common wiring are arranged in parallel and a scanning wiring is provided. And a switching element and a pixel electrode connected to the signal wiring via the switching element, wherein the signal wiring is arranged orthogonal to the common wiring, and arranged in a matrix at the intersection of the scanning wiring and the signal wiring. This is a method of inspecting a liquid crystal panel for defects by operating a liquid crystal by applying an electric field substantially parallel to a substrate surface between a common electrode connected to a common wiring and a pixel electrode. In the first inspection method, when a short-circuit point between a signal wiring and a common wiring is detected, a voltage applied to the common wiring is displayed such that vertical and horizontal line defects having the short-circuiting points as intersections are displayed. The potential difference between the potential of the common wiring and the average potential applied to the signal wiring is set to be larger than the potential difference in normal display.

In the above method, the voltage applied to the common line may be an AC voltage whose value changes with time. At this time, the voltage applied to the common wiring may be any one of a rectangular wave, a triangular wave, and a sawtooth wave having a predetermined frequency. If the resistance value of the liquid crystal of one pixel is Rlc and the capacitance is Clc, the period T of the voltage applied to the common line is
It is preferable to satisfy T ≦ 10 × Rlc × Clc.

In the above method, the voltage of the common line is set so that the difference between the average voltage applied to the signal line and the voltage applied to the common line is equal to or greater than the threshold voltage of the liquid crystal of the liquid crystal panel. You may.

A first liquid crystal panel inspection apparatus according to the present invention has a pair of substrates, on which scanning wiring and common wiring are arranged in parallel and orthogonal to the scanning wiring and common wiring. A switching element and a pixel electrode connected to the signal wiring via the switching element, the signal wiring being arranged in a matrix at an intersection of the scanning wiring and the signal wiring, and being connected to the common wiring. This is a device for inspecting a defect of a liquid crystal panel that operates a liquid crystal by applying an electric field substantially parallel to a substrate surface between a common electrode and a pixel electrode. The first inspection apparatus detects a short-circuit point between the signal wiring and the common wiring so that a vertical and horizontal line defect having the short-circuited point as an intersection is displayed. And a control means for setting the potential difference between the potential of the common wiring and the average potential of the signal wiring to be larger than the potential difference in the case of normal display.

A second liquid crystal panel inspection apparatus according to the present invention has a pair of substrates, on which scan lines and common lines are arranged in parallel and orthogonal to the scan lines and common lines. A switching element and a pixel electrode connected to the signal wiring via the switching element, the signal wiring being arranged in a matrix at an intersection of the scanning wiring and the signal wiring, and being connected to the common wiring. This is a device for inspecting a defect of a liquid crystal panel that operates a liquid crystal by applying an electric field substantially parallel to a substrate surface between a common electrode and a pixel electrode. The second inspection apparatus includes a stage for holding the liquid crystal panel to be inspected, image recognition means for capturing the display on the liquid crystal panel as image information, and control of each wiring of the liquid crystal panel to a predetermined potential for inspection. A signal source for outputting a control signal, laser irradiation means for irradiating a laser beam for repairing a short-circuited portion, driving means for driving the stage in the X and Y directions, and control means. The control means, when detecting a short-circuit point between the signal wiring and the common wiring, a voltage applied to the common wiring, in order to display vertical and horizontal line defects having the short-circuited point as an intersection, The potential of each wiring is controlled so that the potential difference between the potential of the common wiring and the average potential of the signal wiring is larger than the potential difference in the case of normal display, and the display information of the liquid crystal panel at that time captured by the image recognition means. The XY driving means is controlled to move the liquid crystal panel to a desired position such that the laser beam is irradiated to the specified short-circuited part based on the The laser irradiation unit is controlled to repair the short circuit by the laser beam.

A second liquid crystal panel inspection method according to the present invention has a pair of substrates, on which scan wiring and common wiring are arranged in parallel and orthogonal to the scanning wiring and common wiring. A switching element and a pixel electrode connected to the signal wiring via the switching element, the signal wiring being arranged in a matrix at an intersection of the scanning wiring and the signal wiring, and being connected to the common wiring. In this method, a liquid crystal panel is operated by applying an electric field substantially parallel to the substrate surface between the common electrode and the pixel electrode to operate the liquid crystal. The second inspection method displays a line defect along a signal line including a short-circuited portion when detecting a short-circuited portion between a signal line and a common line, and detects a line defect along the common line including the short-circuited portion. Defects are displayed, and intersections of the displayed line defects are specified as short-circuit points.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a liquid crystal panel inspection method and apparatus according to an embodiment of the present invention.

<Embodiment 1> (Inspection method of liquid crystal panel) An embodiment of an inspection method of a liquid crystal panel according to the present invention will be described below. The inspection method for a liquid crystal panel according to the present embodiment is an inspection method for an active matrix type liquid crystal panel as shown in FIG. The liquid crystal panel to be inspected has a pair of substrates sandwiching the liquid crystal. On one of the substrates, the scanning wiring 11 and the common wiring 13 are arranged in parallel, and the signal wiring 14 is arranged in a direction orthogonal to them. A liquid crystal panel in which a signal wiring 14 is connected to a pixel electrode 15 via a switching element 16 such as a thin film transistor (TFT). In particular, the inspection method of the present embodiment is a method of detecting a short circuit (short circuit) between the signal wiring 14 and the common wiring 13 in such a liquid crystal panel and specifying the short-circuited portion.

As described above, conventionally, a voltage for normal display as shown in FIG. 7, for example, has been applied at the time of inspection. Therefore, the voltage of the common line 13 and the signal line 14
The difference between the AC signal and the center voltage of the AC signal depends on the value of the capacitance (parasitic capacitance) of the switching element.
V to about 1 V (1 V (= 8 V−7 in the example of FIG. 7).
V). ). Even if the electrodes having such a voltage difference are short-circuited, the voltage difference is as small as 1 V or less.
Generally, a change in potential due to a short circuit is small. That is, since the difference in signal voltage applied to the liquid crystal between the short-circuited portion and the normal portion is small, the difference in luminance between these portions is also small, and defects in the short-circuited portion are hardly visible. In particular, since the common wiring 13 is commonly connected to other common wirings in the peripheral portion of the display screen, even if there is a short circuit, the voltage change in that part is smaller, and therefore, the direction along the common wiring 13 (FIG. 6) In this case, no horizontal line defect is visible. On the other hand, an AC signal is applied to the signal wiring 14, and the AC signal is easily attenuated by the potential of the common wiring 13.
In the direction along the signal wiring 14 (vertical direction in FIG. 6), line defects were recognized.

Therefore, in the present embodiment, the difference between the voltage applied to the common wiring 13 and the center voltage (average voltage) of the AC signal applied to the signal wiring 14 in the voltage applied to the common wiring 13 at the time of the short-circuit inspection is increased. As described above, the voltage applied to the common wiring 13 is changed from the value at the time of normal display. As a result, even if the resistance value of the short-circuit portion is the same, the potential difference between the vicinity of the short-circuit portion and the power supply portion of the common line 13 increases, so that the liquid crystal applied voltage gradient of the pixel along the common line 13 (see FIG. 2). And the luminance changes, so that line defects along the common wiring 13 can be easily seen. Accordingly, when there is a short part, a line defect in the direction along the signal wiring 14 and a line defect in the direction along the common wiring 13 can be confirmed, and the intersection can be specified as the short part.

For example, as shown in FIG.
3 where the maximum is 11V, the minimum is 5V, and the center value is 8V
A rectangular wave AC signal of 0 Hz is applied, and 1
Apply a DC signal of 3V. In this case, the difference between the voltage 1 of the common wiring 13 and the center voltage 3 of the signal wiring 14 is 5 V
(= 13V-8V), which is larger than the voltage difference 1V (= 8V-7V) at the time of the normal display control shown in FIG.

As described above, by applying a higher voltage to the common line 13 than in the normal display so as to increase the voltage difference between the common line 13 and the signal line 14,
When a short circuit occurs between the common line 13 and the signal line 14, the luminance of the pixels along the common line 13 having the short-circuited portion changes, and a difference occurs with the luminance of the surrounding pixels. Become like The intersection of the bright line indicating the line defect of the common wiring 13 and the bright line indicating the line defect of the signal wiring 14 can be easily confirmed with the naked eye, and the address of the short-circuited portion can be specified. At this time, preferably, the voltage applied to the common wiring 13 is
The difference between the voltage applied to the common wiring 13 and the average voltage applied to the signal wiring 14 is set to be larger than the threshold voltage when the liquid crystal is operated.

(Verification Result) The result of the specific verification using the above-described inspection method will be described below. First, a result of a case where a liquid crystal panel having a short circuit at a part of the intersection between the signal wiring 14 and the common wiring 13 is verified by a conventional method will be described.

Signal wiring 14, scanning wiring 11, common wiring 1
3 were selected one by one, and a voltage waveform for normal display shown in FIG. 7 was applied by applying a probe to each electrode pad. At this time, the signal wiring voltage 2 of the signal wiring 14 is
30Hz rectangular wave, maximum value is 11V, minimum value is 5
Therefore, the signal wiring voltage center value 3 of the signal wiring 14 is 8V. On the other hand, the common wiring voltage 1 of the common wiring 13 is 7
V, and the potential difference between the signal wiring voltage center value 3 and the common wiring voltage 1 is 1 V. Further, although not shown, in order to perform the on / off operation of the switching element 16, the scanning wiring 11 is supplied with + 20V when turned on and -5V when turned off.
The display is performed by applying the following pulse. The transmittance-voltage characteristics of the liquid crystal panel used at this time are as shown in FIG. Since the voltage applied to the liquid crystal is 3 V, a halftone display with a transmittance of about 18% is obtained. The threshold voltage (V10) of the liquid crystal panel is 2.5V. At this time, the pixels along the short-circuited signal wiring 14 were recognized as line defects that seemed darker than the peripheral pixels, but the pixels along the common wiring 13 were recognized as line defects without any change in peripheral luminance. Therefore, it was not possible to specify where in the plurality of common wirings 13 arranged in parallel a short-circuit occurred.

Next, according to the inspection method of this embodiment,
When the voltage applied to the common line 13 is set to 13 V as shown in FIG. 1, the luminance of the pixels along the common line 13 having the short-circuit portion changes and differs from the luminance of the surrounding pixels. A line defect was observed along. This makes it possible to easily visually check the intersection of the line with different luminance along the common wiring 13 and the line with different luminance along the signal wiring 14, and to specify the address of the short-circuited portion. Became. The common wiring 13
After a while after the switching of the applied voltage, the line defect along the common wiring 13 disappeared.

Then, the address of the intersection of the bright line along the common line 13 including the short-circuited portion and the bright line along the signal line 14 is confirmed, and the signal line 14 at that address is checked.
Was separated from the common wiring 13 with a laser and inspected again by the same method. As a result, no change in the luminance of the pixels along the common wiring 13 was observed. That is, it was confirmed that the short was eliminated by separating the short with a laser.

As described above, it has been verified that the short-circuit portion of the signal wiring 14 and the common wiring 13 can be specified by the inspection method of the present embodiment.

<Embodiment 2> The present embodiment differs from the inspection method of Embodiment 1 in that the voltage applied to the common wiring 13 at the time of inspection is an AC voltage that changes with time.

In the above-described verification, when a DC signal having no temporal change as shown in FIG. 1 is applied to the common wiring 13, when a certain time elapses after the voltage 1 of the common wiring 13 is applied, It was confirmed that the display of the line defect along the common wiring 13 disappeared. It is considered that such a phenomenon occurs because the amount of change in the voltage is attenuated due to the time constant of the liquid crystal over time immediately after the voltage is applied to the common wiring 13.

Therefore, in order to prevent a change in luminance from being recognized due to such attenuation, an AC voltage 1 that fluctuates with time at a certain frequency is applied to the common wiring 13 as shown in FIG. The AC voltage 1 depends on the time constant of the liquid crystal of one pixel of the liquid crystal panel to be used and the resistance of the short-circuit portion, but the electric charge stored in the liquid crystal is discharged at five times the time constant of the liquid crystal and the voltage does not change. In consideration of this, it is necessary to apply the voltage at a period T smaller than 10 times the time constant (= Rlc × Clc) of the liquid crystal of at least one pixel. That is, the cycle T of the AC voltage is determined so as to satisfy the following relationship, where Rlc is the resistance value of the liquid crystal of one pixel and Clc is the capacitance. T ≦ 10 × Rlc × Clc

For example, when the time constant of the liquid crystal of one pixel of the liquid crystal panel is about 10 seconds, the common wiring 13 has a maximum value of 13 V, a minimum value of 6 V and a frequency of 0.1 H as shown in FIG.
An inspection is performed by applying a rectangular wave of z. In this case, since the frequency is the same as the time constant of the liquid crystal, the line defect in the direction along the common wiring 13 does not disappear, and the defect location of the short-circuit portion can be easily specified.

FIG. 4 is a view for explaining how a line defect is displayed when the AC voltage is applied to the common wiring 13. As shown in FIG. 4A, when the point A is a short-circuit point between the common wiring 13 and the signal wiring 14, the common wiring 1
3 is applied with an AC waveform voltage as shown in FIG. When the voltage applied to the common wiring 13 changes as shown in FIG. 4B, at timing x, defective lines having different luminances are displayed vertically and horizontally around the short point A (FIG. 4).
(X)). Thereafter, at timing y, the common wiring 1
The display of the line defects in the horizontal direction along line 3 fades (see FIG. 4).
(See (y)), at the timing z, the display of the line defect in the horizontal direction disappears (see FIG. 4 (z)). Thereafter, in accordance with the change of the AC voltage to the common wiring 13, similarly, FIG.
The display states from (x) to (z) are repeated. At this time, by setting the period T of the AC voltage to be sufficiently short, that is, by setting T ≦ 10 × Rlc × Clc, the display of the vertical and horizontal line defects can be clarified. Since A can be specified, it is possible to specify a short part.

In the present embodiment, the AC voltage applied to the common wiring 13 at the time of inspection is a rectangular wave. However, the waveform is not limited to a rectangular wave. It may be a wave or a sine wave.

<Third Embodiment> (Inspection Apparatus for Liquid Crystal Panel) In the following, using the inspection method of the above-described embodiment, a short-circuited portion between the wirings of the liquid crystal panel is detected, the position is specified, and the short-circuit is determined. 1 shows a liquid crystal panel inspection device having a function of repairing a part.

FIG. 5 shows a configuration of an inspection apparatus for an active matrix type liquid crystal panel according to the present embodiment. As shown in the figure, the inspection apparatus includes a backlight 35 that illuminates a liquid crystal (LCD) panel 31 to be inspected, an LCD display signal source 41 that generates a display signal for inspecting the liquid crystal panel 31, An image recognition unit 47 for recognizing a display on the liquid crystal panel;
The control unit 43 includes a control unit 43 that controls the operation of the entire inspection apparatus, and a monitor 53 that performs various displays for the operator. The control unit 43 is connected to a control information input unit 51 for inputting control information and a control information storage medium 49 for recording control information. The control information storage medium 49 stores control information necessary for inspection and repair, for example, information such as a voltage of a common wiring and a laser output power value at the time of inspection.

Further, the inspection apparatus includes an XY stage 33 for holding the liquid crystal panel 31 to be inspected, an LCD panel transport section 37 for transporting the liquid crystal panel 31 onto the XY stage 33, and an XY stage 33. An X-Y drive section 39 for moving the laser beam in two orthogonal directions (X and Y directions), and a laser irradiation section 45 for irradiating a laser for repairing a short-circuit point detected in the liquid crystal panel 31 are provided. .

The entire operation of the inspection apparatus configured as described above is controlled by the control unit 43. For example, the display signal to be output from the LCD display signal source 41 is determined by the control unit 43. Further, the XY driving section 39 outputs a control signal for moving the XY stage 33 by a predetermined amount in the X direction and the Y direction based on the control section 43. The backlight 35 is turned on and off by the control unit 43. The control section 43 also controls the laser output operation of the laser irradiation section 45 and its output power.

Hereinafter, the operation of detecting a short-circuited portion and repairing the short-circuited portion in the inspection apparatus will be described in detail.

The controller 43 controls the LCD display signal source 41 to output a display signal to the liquid crystal panel 31 for controlling the voltage applied to the common wiring, the signal wiring, and the scanning wiring to a predetermined voltage for inspection. . That is, the control unit 43 controls the potentials of the common wiring and the signal wiring of the liquid crystal panel 31 to be inspected in accordance with the inspection method described in the first or second embodiment. At this time, if there is a short-circuit between the common wiring and the signal wiring, the liquid crystal panel 31 shown in FIG.
Line defects appear as shown in FIG. That is, lines (line defects) having different luminances are displayed vertically and horizontally on the liquid crystal panel 31 as shown in FIGS. The display is fetched as image information by the image recognition unit 47 and the control unit 4
In step 3, the address of the intersection of these lines is obtained. This address information is recorded on the control information storage medium 49. As described above, for all the common wirings and signal wirings of the liquid crystal panel 31, a short-circuited part between the common wiring and the signal wiring on the substrate is detected, and the address of the short-circuited part is obtained.

When the address of the short point between the common wiring and the signal wiring is specified, the inspection device repairs the short point by irradiating the position on the substrate indicated by the address with a laser beam. To this end, the control unit 43 controls the XY drive unit 39 based on the address, and controls the XY stage so that the laser beam output from the laser irradiation unit 45 is irradiated onto the position indicated by the address. 33 and the laser irradiation unit 45 are driven. The control unit 43 repeats the above-described processing so that the short positions of all the addresses recorded in the control information storage medium 49 are restored by the laser beam.

As described above, the inspection apparatus for a liquid crystal panel according to the present embodiment can identify and repair a short-circuited portion between the common wiring and the signal wiring on the substrate of the liquid crystal panel, and can correct a line defect failure due to the short-circuit. Can be reduced, and the manufacturing yield of the array substrate can be greatly improved.

[0042]

According to the inspection method of the present invention, when there is a short circuit between the common wiring and the signal wiring in the liquid crystal panel, line defects are displayed in the vertical and horizontal directions around the short. At this time, since the intersection of the vertical and horizontal line defects can be recognized as a short-circuited portion, the address of the short-circuited portion can be specified, and repair processing by laser irradiation or the like can be performed in a later step. As a result, it is possible to reduce line defect defects due to short-circuits between the wirings of the liquid crystal panel, and it is possible to greatly improve the production yield of the array substrate.

According to the inspection apparatus of the present invention, the address of the short-circuited portion on the liquid crystal panel substrate can be specified, and the repair processing by laser beam irradiation can be performed. The manufacturing yield of the array substrate can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing voltage waveforms applied to respective electrodes in a liquid crystal panel inspection method according to a first embodiment of the present invention.

FIG. 2 is a diagram showing transmittance-voltage characteristics of a liquid crystal panel.

FIG. 3 is a diagram showing a voltage waveform applied to each electrode in a liquid crystal panel inspection method according to a second embodiment of the present invention.

FIG. 4 is a diagram illustrating a change in display of a liquid crystal panel when there is a defective portion in inspection by the inspection method according to the second embodiment.

FIG. 5 is a diagram showing a configuration of a liquid crystal panel inspection apparatus according to the present invention.

FIG. 6 is a plan view schematically showing a plane configuration of a substrate on which an active matrix array of an active matrix type liquid crystal panel in the IPS system is formed.

FIG. 7 shows a voltage waveform applied to each electrode in a conventional defect inspection method for a liquid crystal panel (applied voltage waveform for normal display).
FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Applied voltage to common wiring 2 Applied voltage to signal wiring 3 Central value of applied voltage to signal wiring 11 Scanning wiring 12 Common electrode 13 Common wiring 14 Signal wiring 15 Pixel electrode 16 Switching element 17 Storage capacitor part 18 Common wiring Electrode pad 19 Contact hole 20 Electrode pad for signal wiring 31 Liquid crystal panel 33 XY stage 39 XY drive unit 41 LCD display signal source 43 Control unit 45 Laser irradiation unit 47 Image recognition unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H088 FA13 FA15 FA30 HA02 HA08 MA20 2H092 GA14 JA24 MA47 MA58 NA30 5B057 AA03 BA02 BA19 DA04 DB02 DB05 DB09 DC22

Claims (12)

[Claims] A scanning wiring and a common wiring are arranged on one of the substrates, and a scanning wiring and a common wiring are arranged in parallel with each other and a signal wiring is arranged orthogonal to the scanning wiring and the common wiring. Are arranged in a matrix at the intersection of
A switching element and a pixel electrode connected to a signal wiring through the switching element; and applying an electric field substantially parallel to a substrate surface between the common electrode connected to the common wiring and the pixel electrode to form a liquid crystal. A method for inspecting a defect of a liquid crystal panel to be operated, wherein when detecting a short-circuit portion between a signal wiring and a common wiring, vertical and horizontal line defects having the short-circuiting point as an intersection are displayed. A liquid crystal panel inspection, wherein a voltage applied to the common wiring is set such that a potential difference between a potential of the common wiring and an average potential applied to the signal wiring is larger than the potential difference in a normal display. Method. 2. The method according to claim 1, wherein the voltage applied to the common wiring is an AC voltage whose value changes with time.
Inspection method of the liquid crystal panel described. 3. The liquid crystal panel inspection method according to claim 2, wherein the voltage applied to the common wiring is any one of a rectangular wave, a triangular wave, and a sawtooth wave having a predetermined frequency. 4. The liquid crystal of one pixel, wherein Rlc is a resistance value and Clc is a capacitance, a period T of a voltage applied to the common line satisfies T ≦ 10 × Rlc × Clc. Item 3. The method for inspecting a liquid crystal panel according to Item 2. 5. The voltage of the common line is set so that a difference between an average voltage applied to the signal line and a voltage applied to the common line is equal to or larger than a threshold voltage value of liquid crystal of a liquid crystal panel. The method for inspecting a liquid crystal panel according to claim 1, wherein: 6. A pair of substrates, wherein a scanning line and a common line are arranged in parallel on one substrate, and a signal line is arranged orthogonal to the scanning line and the common line. Are arranged in a matrix at the intersection of
A switching element and a pixel electrode connected to a signal wiring through the switching element; and applying an electric field substantially parallel to a substrate surface between the common electrode connected to the common wiring and the pixel electrode to form a liquid crystal. An apparatus for inspecting a defect of a liquid crystal panel to be operated, wherein when detecting a short-circuit point between a signal wiring and a common wiring, vertical and horizontal line defects having the short-circuiting point as an intersection are displayed. The liquid crystal panel according to claim 1, further comprising control means for setting a voltage applied to the common wiring so that a potential difference between a potential of the common wiring and an average potential of the signal wiring is larger than the potential difference in a normal display. Inspection equipment. 7. The voltage applied to the common line is an AC voltage whose value changes with time.
The inspection device for a liquid crystal panel described in the above. 8. The inspection apparatus for a liquid crystal panel according to claim 7, wherein the voltage applied to the common wiring is any one of a rectangular wave, a triangular wave, and a sawtooth wave having a predetermined frequency. 9. The liquid crystal of one pixel, wherein Rlc is a resistance value and Clc is a capacitance, a period T of a voltage applied to the common line satisfies T ≦ 10 × Rlc × Clc. Item 7. An inspection device for a liquid crystal panel according to Item 7. 10. The voltage of the common line is set so that a difference between an average voltage applied to the signal line and a voltage applied to the common line is equal to or larger than a threshold voltage value of a liquid crystal of a liquid crystal panel. The inspection apparatus for a liquid crystal panel according to claim 6, wherein: 11. A pair of substrates, wherein a scanning line and a common line are arranged in parallel on one substrate, and a signal line is arranged orthogonal to the scanning line and the common line. Having a switching element and a pixel electrode connected to a signal wiring via the switching element, and arranged on a substrate surface between the common electrode connected to a common wiring and the pixel electrode. On the other hand, in a device for inspecting a defect of a liquid crystal panel which operates a liquid crystal by applying a substantially parallel electric field, a stage for holding a liquid crystal panel to be inspected, an image recognizing means for capturing a display on the liquid crystal panel as image information, and a liquid crystal panel. A signal source for outputting a control signal for controlling each of the wirings to a predetermined potential for inspection, and a laser irradiating means for irradiating a laser beam for repairing a short-circuit portion Driving means for driving the stage in the X and Y directions; and detecting a short-circuit point between the signal wiring and the common wiring so that vertical and horizontal line defects having the short-circuit point as an intersection are displayed. In order to perform image recognition, the voltage applied to the common wiring is controlled such that the potential difference between the potential of the common wiring and the average potential of the signal wiring is larger than the potential difference in the normal display. The short-circuited portion of the liquid crystal panel is specified based on the display information of the liquid crystal panel at that time taken by the means, and the XY driving means is controlled so that the specified short-circuited portion is irradiated with the laser beam. And a control means for controlling said laser irradiation means to repair said short circuit by the laser beam from said laser irradiation means. . 12. A pair of substrates, wherein a scanning line and a common line are arranged in parallel on one substrate, and a signal line is arranged orthogonal to the scanning line and the common line. Having a switching element and a pixel electrode connected to a signal wiring via the switching element, and arranged on a substrate surface between the common electrode connected to a common wiring and the pixel electrode. A method of inspecting a liquid crystal panel for operating a liquid crystal by applying a substantially parallel electric field, the method comprising: detecting a short-circuit portion between a signal wire and a common wire along a signal wire including the short-circuit portion; A method for inspecting a liquid crystal panel, comprising displaying a line defect along a common wiring including the short-circuited portion, and specifying an intersection of the displayed line defect as a short-circuited portion.