JP3618302B2 - Inspection method and inspection device for liquid crystal panel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal panel suitable as a display for AV equipment, OA equipment, etc., and more particularly to a method and apparatus for inspecting a defect of an active matrix liquid crystal panel.
[0002]
[Prior art]
Currently, liquid crystal display panels have been applied in various fields such as video camera viewfinders, pocket TVs, high-definition projection TVs, personal computers, word processors, and other information display terminals. It is active. 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 a high contrast is maintained even when a large capacity display is performed. It is extremely expensive, and it is actively developed and commercialized as a favorite of notebook PCs and large-scale, large-capacity full-color monitors.
[0003]
In such an active matrix liquid crystal display panel, a widely used liquid crystal display mode is a TN (Twisted Nematic) system. In the TN system, 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 such that their polarization axes are orthogonal to each other, and one polarizing plate is arranged so that its polarization axis is parallel or perpendicular to the major axis direction of the liquid crystal molecules in contact with one substrate. When no voltage is applied between the two substrates, that is, to the liquid crystal panel, white display is performed. However, when a voltage is applied in the vertical direction with respect to the liquid crystal panel, the light transmittance gradually decreases to display black. It becomes. Such display characteristics can be obtained because when a voltage is applied to the liquid crystal panel, the liquid crystal molecules are aligned in the direction of the electric field while unwinding the twisted structure. This is because the polarization state of the light changes 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. Therefore, the light transmittance varies depending on the incident direction. That is, the characteristics of the liquid crystal panel have a viewing angle dependency. Such viewing angle dependency influences the image quality of the liquid crystal panel because an inversion phenomenon of luminance occurs when the viewpoint is inclined obliquely 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).
[0004]
In order to improve the viewing angle dependency, an IPS is used in which the direction of the electric field applied to the liquid crystal is substantially parallel to the substrate, instead of applying an electric field in the vertical direction of the substrate as in the TN liquid crystal display system. The (In-Plane Switching) method has been devised, and disclosed in, for example, Japanese Patent Publication No. 63-21907 and Japanese Patent Laid-Open No. 6-160878.
[0005]
FIG. 6 shows a configuration of an active matrix array substrate of a general IPS 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 the electrode pads 19 and the signal wirings 14 are connected to the electrode pads 20, respectively. A switching element 16 is provided at each intersection of the scanning wiring 11 and the signal wiring 14. A thin film transistor is usually used as the switching element 16, 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. Furthermore, in order to protect the switching element 16 from static electricity that may normally occur in the process of manufacturing the panel, a power supply wiring (not shown) that connects the signal wirings 14 and the scanning wirings 11 outside the electrode pads. Z).
[0006]
A plurality of (for example, two) pixel electrodes 15 are formed in one pixel region surrounded by two adjacent scanning lines 11 and two adjacent signal lines 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. A storage capacitor portion 17 is formed between the pixel electrodes 15 and above the scanning wiring 11. The common electrode 12 is connected to a common wiring 13 formed between two adjacent scanning wirings 11. Each common wiring 13 is connected to another common wiring through a contact hole 19 and is collectively connected to a common wiring electrode pad 18. Note that an insulator layer (not shown) exists at the intersection of the scanning wiring 11 and the common wiring 13 and the signal wiring 14.
[0007]
[Problems to be solved by the invention]
In general, when an active matrix array substrate is manufactured, a short circuit may occur between electrode wirings due to a defect during patterning. Therefore, after completion of the array substrate, an inspection for confirming the existence of such a defect is usually performed. In this panel inspection, the power supply wiring for countermeasures against static electricity is generally removed, and then a predetermined voltage is applied to each of the signal wiring and the scanning wiring by applying a probe (probe) to each electrode pad. Then, an electrical inspection is performed to directly identify the wiring that is short-circuited. Here, the predetermined voltage used for the inspection is, for example, a voltage applied to each wiring during normal display as shown in FIG. That is, in FIG. 7, a DC voltage 1 (7V) is applied to the common wiring, and a rectangular wave AC voltage 3 (5V, 11V) having a center voltage 3 (8V) is applied to the signal wiring. If the short 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.
[0008]
In the case of a normal TN type active matrix array substrate, there are only signal wirings and scanning wirings on the substrate, and therefore a short circuit between the wirings occurs only between the signal wirings and the scanning wirings. On the other hand, in the case of the active matrix array substrate of the IPS system as described above, since the common wiring 13 is provided in addition to the signal wiring 14 and the scanning wiring 11, the short circuit is only between the signal wiring 14 and the scanning wiring 11. However, this also occurs between the signal wiring 14 and the common wiring 13, and also between the scanning wiring 11 and the common wiring 13.
[0009]
In the case of the substrate configuration as described above, the scanning wiring 11 and the common wiring 13 are formed by performing the same film forming process and patterning in the same photolithography process, so that a short portion between the wirings can be found by visual inspection. it can. However, a short circuit between the signal wiring 14 and the common wiring 13 is caused by an interlayer insulation defect such as a pin hole in the insulating layer, as in the case of the signal wiring 14 and the scanning wiring 11, and therefore, the short circuit portion can be visually determined. I can't. Furthermore, the conventional common electrode 12 has a configuration in which all the pixels are collectively connected as described above. When an interlayer short circuit occurs between the common wiring 13 and the signal wiring 14, the above 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 even the short circuit part. That is, in the conventional method, when there is a short portion, a line defect is seen in the direction along the signal wiring 14, but no line defect is seen in the direction along the common wiring 13. It was not possible to determine which of the pixels along the line was defective.
[0010]
The present invention has been made to solve the above-described problems, and an object of the present invention is an inspection method of an active matrix type liquid crystal panel, and an inspection method and inspection capable of specifying a short-circuit portion between a common wiring and a signal wiring. To provide an apparatus.
[0011]
[Means for Solving the Problems]
According to the present inventionLCD panelThe inspection method includes a pair of substrates, the scanning wiring and the common wiring are arranged in parallel on one substrate, and the signal wiring is arranged orthogonal to the scanning wiring and the common wiring. A switching element and a pixel electrode connected to the signal wiring through the switching element, arranged in a matrix at the intersection ofAll of the inspection areaCommon electrode connected to common wiringpadAnd inspecting for defects in the liquid crystal panel that operates the liquid crystal by applying an electric field substantially parallel to the substrate surface between the pixel electrodes. ThatInspection methodIsWhen inspecting the LCD panelCommonElectrode padThe voltage difference between the common wiring potential and the average potential applied to the signal wiring isPotential difference when displaying images during normal operation of the LCD panelSet to be larger thanThus, the vertical and horizontal line defects are displayed on the liquid crystal panel, and the intersection of the vertical line defect and the horizontal line defect is specified as a short-circuit location.
[0012]
Common to the above methodsElectrode padThe voltage applied to may be an alternating voltage whose value changes with time. At this time, commonElectrode padThe voltage applied to may be any of a rectangular wave, a triangular wave, and a sawtooth wave having a predetermined frequency. Also, if the resistance value of the liquid crystal of one pixel is Rlc and the capacitance is Clc, it is commonElectrode padIt is preferable that the period T of the voltage applied to the voltage satisfies T ≦ 10 × Rlc × Clc.
[0013]
In the above method, the common voltage is applied so that the difference between the average voltage applied to the signal wiring and the voltage applied to the common wiring is equal to or higher than the threshold voltage value of the liquid crystal of the liquid crystal panel.Electrode padMay be set.
[0014]
The inspection apparatus for a first liquid crystal panel according to the present invention has a pair of substrates, the scanning wiring and the common wiring are arranged in parallel on one substrate, and the signal wiring is orthogonal to the scanning wiring and the common wiring. Are arranged in a matrix at the intersection of the scanning wiring and the signal wiring, and have a switching element and a pixel electrode connected to the signal wiring through the switching element,All of the inspection areaCommon electrode connected to common wiringpadIs a device for inspecting a defect of a liquid crystal panel in which a liquid crystal is operated by applying an electric field substantially parallel to the substrate surface between the pixel electrodes. The inspection device for the first liquid crystal panel isWhen inspecting the LCD panelCommonElectrode padThe voltage difference between the common wiring potential and the signal wiring average potential isWhen displaying images during normal operation of the LCD panelSet to be larger than the potential difference ofThus, the vertical and horizontal line defects are displayed on the liquid crystal panel, and the intersection of the vertical line defect and the horizontal line defect is specified as a short-circuited portion.Control means are provided.
[0015]
The inspection apparatus for a second liquid crystal panel according to the present invention has a pair of substrates, the scanning wiring and the common wiring are arranged in parallel on the one substrate, and the signal wiring is orthogonal to the scanning wiring and the common wiring. Are arranged in a matrix at the intersection of the scanning wiring and the signal wiring, and have a switching element and a pixel electrode connected to the signal wiring through the switching element,All of the inspection areaCommon electrode connected to common wiringpadIs a device for inspecting a defect of a liquid crystal panel for operating a liquid crystal by applying an electric field substantially parallel to the substrate surface between the pixel electrodes. The second inspection apparatus controls a stage for holding a liquid crystal panel to be inspected, an image recognition means for capturing a display on the liquid crystal panel as image information, and each wiring of the liquid crystal panel to a predetermined potential for inspection. A signal source for outputting the control signal, a laser irradiation means for irradiating a laser beam for repairing the short-circuited portion, a drive means for driving the stage in the X and Y directions, and a control means.
The control meansWhen inspecting the LCD panelCommonElectrode padThe voltage difference between the common wiring potential and the signal wiring average potential isWhen displaying images during normal operation of the LCD panelTo be larger than the potential difference ofControl, so that the vertical and horizontal line defects are displayed on the LCD panel,Based on the current display information of the liquid crystal panel captured by the image recognition meansThe intersection of the vertical line defect and the horizontal line defectLCD panel short-circuit locationAsTo identify and move the liquid crystal panel to a desired position by controlling the XY drive means so that the laser beam is irradiated to the specified short-circuited portion, and to repair the short-circuit by the laser beam from the laser irradiation means The laser irradiation means is controlled.
[0016]
The method for manufacturing a liquid crystal panel according to the present invention has a pair of substrates, on which scanning wiring and common wiring are arranged in parallel, and signal wiring is arranged orthogonal to the scanning wiring and common wiring. And a common electrode pad and a pixel that are arranged in a matrix at the intersection of the scanning wiring and the signal wiring, have a switching element and a pixel electrode connected to the signal wiring through the switching element, and are connected to the common wiring This is a method of manufacturing a liquid crystal panel in which an electric field substantially parallel to the substrate surface is applied between electrodes to operate the liquid crystal. The manufacturing method includes a step of inspecting a liquid crystal panel for defects using the above-described inspection method of the present invention.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a liquid crystal panel inspection method and inspection apparatus according to the present invention will be described below in detail with reference to the accompanying drawings.
[0018]
<Embodiment 1>
(LCD panel inspection method)
Embodiments of a liquid crystal panel inspection method according to the present invention will be described below.
The liquid crystal panel inspection method shown in this embodiment is an inspection method for an active matrix liquid crystal panel as shown in FIG. The liquid crystal panel to be inspected has a pair of substrates that sandwich the liquid crystal, the scanning wiring 11 and the common wiring 13 are arranged in parallel on one substrate, and the signal wiring 14 is arranged in a direction orthogonal to them. A liquid crystal panel in which the signal wiring 14 is connected to the 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.
[0019]
As described above, conventionally, for example, a normal display voltage as shown in FIG. 7 has been applied during inspection. Accordingly, the voltage difference between the voltage of the common wiring 13 and the center voltage of the AC signal of the signal wiring 14 is approximately 0 V to 1 V, although it depends on the value of the capacitance (parasitic capacitance) of the switching element (FIG. 7). In this example, 1V (= 8V-7V).) Even if the electrodes having such a voltage difference are short-circuited, the voltage difference is as small as 1 V or less, so that the potential change due to the short-circuit is generally small. That is, since the difference in signal voltage applied to the liquid crystal between the shorted portion and the normal portion is small, the luminance difference between these portions is also small, and the defect in the short portion is difficult to see. In particular, since the common line 13 is commonly connected to other common lines in the periphery of the display screen, even if short-circuited, the voltage change in that part is smaller. Therefore, the direction along the common line 13 (FIG. 6). In the horizontal direction) line defects are not visible. On the other hand, an AC signal is applied to the signal wiring 14, and this AC signal is likely to be attenuated by the potential of the common wiring 13, so that a line defect is recognized in the direction along the signal wiring 14 (vertical direction in FIG. 6). It was.
[0020]
Therefore, in the present embodiment, the voltage applied to the common wiring 13 at the time of short-circuit inspection is such that the difference between the voltage of the common wiring 13 and the center voltage (average voltage) of the AC signal applied to the signal wiring 14 increases. The voltage applied to the common wiring 13 is changed from the value during normal display. As a result, even if the resistance value of the short portion is the same, the potential difference between the vicinity of the short portion and the power supply portion of the common wiring 13 increases, so that the liquid crystal applied voltage gradient of the pixels along the common wiring 13 (see FIG. 2) And the luminance change occurs, so that the line defect along the common wiring 13 can be easily seen. As a result, when a short portion exists, a line defect in the direction along the common wiring 13 can be confirmed along with the line defect in the direction along the signal wiring 14, and the intersection can be specified as the short portion.
[0021]
For example, as shown in FIG. 1, a 30-Hz rectangular wave AC signal having a maximum of 11 V, a minimum of 5 V, and a center value of 8 V is applied to the signal wiring 14, and a 13 V DC signal is applied to the common wiring 13. In this case, the difference between the voltage 1 of the common line 13 and the center voltage 3 of the signal line 14 is 5V (= 13V−8V), and the voltage difference 1V (= 8V−7V) during the normal display control shown in FIG. ) Larger than
[0022]
Thus, a short circuit occurs between the common line 13 and the signal line 14 by applying a voltage higher than that during normal display to the common line 13 so that the voltage difference between the common line 13 and the signal line 14 becomes large. Sometimes, the luminance of the pixels along the common wiring 13 having the short-circuited portion changes, and a difference from the luminance of the surrounding pixels is generated, so that it appears as a line defect of the common wiring 13. 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 portion can be specified. At this time, preferably, the voltage applied to the common wiring 13 is such that the difference between the voltage applied to the common wiring 13 and the average voltage applied to the signal wiring 14 is larger than the threshold voltage value when the liquid crystal is operated. Set to be larger.
[0023]
(inspection result)
The results of specific verification using the above inspection method will be described below. First, a result when the liquid crystal panel having a short circuit at a part of the intersection of the signal wiring 14 and the common wiring 13 is verified by a conventional method is shown.
[0024]
The signal wiring 14, the scanning wiring 11, and the common wiring 13 were selected one by one, a probe (probe) was applied to each electrode pad, and a voltage waveform for normal display shown in FIG. 7 was applied. At this time, the signal wiring voltage 2 of the signal wiring 14 is a rectangular wave of 30 Hz, the maximum value is 11V, and the minimum value is 5V. Therefore, the signal wiring voltage central value 3 of the signal wiring 14 is 8V. On the other hand, the common wiring voltage 1 of the common wiring 13 is 7V, and the potential difference between the signal wiring voltage center value 3 and the common wiring voltage 1 is 1V. Further, although not shown, in order to perform the on / off operation of the switching element 16, the scanning wiring 11 is displayed by applying a pulse of + 20V when turned on and −5V when turned off. 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, 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 pixel along the shorted signal wiring 14 was recognized as a line defect that looks darker than the peripheral pixels, but the pixel along the common wiring 13 was recognized as a line defect without changing the peripheral luminance. Therefore, it was not possible to identify where the plurality of common wires 13 arranged in parallel were short-circuited.
[0025]
Next, according to the inspection method of the present embodiment, when the voltage applied to the common wiring 13 is set to 13 V as shown in FIG. 1, the luminance of the pixels along the common wiring 13 having the short portion changes, and the surrounding pixels are changed. Therefore, line defects were observed along the common wiring 13. Thereby, the intersection of the line with different luminance along the common wiring 13 and the line with different luminance along the signal wiring 14 can be easily visually confirmed, and the address of the short portion can be specified. Became. It should be noted that the line defects along the common wiring 13 disappeared after a while had passed since the applied voltage of the common wiring 13 was switched.
[0026]
Then, the address of the intersection of the bright line along the common wiring 13 including the short portion and the bright line along the signal wiring 14 is confirmed, and the signal wiring 14 at the address is separated from the common wiring 13 by a laser, and the same method is performed again. As a result, the luminance change of the pixels along the common wiring 13 was not recognized this time. In other words, it was confirmed that the short circuit was eliminated by cutting the short circuit with a laser.
[0027]
As described above, it was verified that the short-circuit portion of the common wiring 13 can be specified for the signal wiring 14 by the inspection method of the present embodiment.
[0028]
<Embodiment 2>
The present embodiment is different from the inspection method of the first embodiment in that the voltage applied to the common wiring 13 at the time of inspection is an alternating voltage that changes with time.
[0029]
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, the common wiring 13 It was confirmed that the display of line defects along the line disappeared. It is considered that such a phenomenon occurs because the amount of change in voltage attenuates due to the time constant of the liquid crystal as time elapses immediately after the voltage is applied to the common wiring 13.
[0030]
Therefore, in order to prevent the change in luminance from being recognized due to such attenuation, as shown in FIG. 3, an alternating voltage 1 that varies with time at a certain frequency is applied to the common wiring 13. 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 portion, but the electric charge stored in the liquid crystal is discharged at 5 times the time constant of the liquid crystal, and the voltage change is eliminated. Considering this, it is necessary to apply 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 period T of the alternating 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
[0031]
For example, when the time constant of the liquid crystal of one pixel of the liquid crystal panel is about 10 seconds, a rectangular wave having a maximum value of 13 V, a minimum value of 6 V and a frequency of 0.1 Hz is applied to the common wiring 13 as shown in FIG. Perform an inspection. 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 will not disappear, and it becomes easier to specify the defect location of the shorted portion.
[0032]
FIG. 4 is a diagram for explaining how line defects are displayed when the above-described AC voltage is applied to the common wiring 13. As shown in FIG. 4A, when the point A is a short-circuit portion between the common wiring 13 and the signal wiring 14, an AC waveform voltage as shown in FIG. 4B is applied to the common wiring 13. When the applied voltage to the common wiring 13 changes as shown in FIG. 4B, at the timing x, defect lines having different luminances are displayed vertically and horizontally around the shorted portion A (see FIG. 4X). ). After that, at the timing y, the display of the horizontal line defect along the common wiring 13 is faded (see FIG. 4 (y)), and at the timing z, the display of the horizontal line defect disappears (FIG. 4). (See (z)). Thereafter, in accordance with the change of the AC voltage to the common wiring 13, the display states of FIGS. 4 (x) to (z) are repeated in the same manner. At this time, by setting the period T of the alternating voltage sufficiently short, that is, by setting so as to satisfy T ≦ 10 × Rlc × Clc, the display of the vertical and horizontal line defects can be clarified, and the intersection point Since A can be specified, it is possible to specify a short portion.
[0033]
In the present embodiment, the AC voltage applied to the common wiring 13 at the time of the inspection is a rectangular wave. However, the waveform is not limited to the rectangular wave. If the waveform changes periodically, a triangular wave, a sawtooth wave, and a sine wave are used. It may be a wave.
[0034]
<Embodiment 3>
(LCD panel inspection equipment)
Hereinafter, a liquid crystal panel inspection apparatus having a function of detecting a short-circuited portion between wirings of the liquid crystal panel by using the inspection method of the above-described embodiment, specifying the position thereof, and repairing the short-circuited portion will be described.
[0035]
FIG. 5 shows the configuration of an inspection apparatus for an active matrix liquid crystal panel according to this 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 inspection of the liquid crystal panel 31, and an inspection time. An image recognition unit 47 that recognizes the display on the liquid crystal panel, a control unit 43 that controls the operation of the entire inspection apparatus, and a monitor 53 that performs various displays for the operator. A control information input unit 51 for inputting control information and a control information storage medium 49 for recording control information are connected to the control unit 43. The control information storage medium 49 stores control information necessary for inspection and repair, for example, information such as the voltage of the common wiring at the time of inspection and the output power value of the laser.
[0036]
Further, the inspection apparatus orthogonally crosses the XY stage 33, the XY stage 33 that holds the liquid crystal panel 31 to be inspected, the LCD panel transport unit 37 that transports the liquid crystal panel 31 onto the XY stage 33, and the XY stage 33. An XY drive unit 39 that moves in two directions (X and Y directions) and a laser irradiation unit 45 that irradiates a laser for repairing a short-circuited portion detected in the liquid crystal panel 31 are provided.
[0037]
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. The XY drive unit 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 unit 43. The backlight 35 is turned on / off by the control unit 43. Further, the laser output operation of the laser irradiation unit 45 and its output power are also controlled by the control unit 43.
[0038]
Hereinafter, detection of a short portion and repair operation of the short portion in the inspection apparatus will be described in detail.
[0039]
The control unit 43 controls the LCD display signal source 41 and causes the liquid crystal panel 31 to output a display signal 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 according to the inspection method shown in the first or second embodiment. At this time, if there is a short portion between the common wiring and the signal wiring, a line defect appears on the liquid crystal panel 31 as shown in FIGS. 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 captured by the image recognition unit 47 as image information, and the control unit 43 obtains the address of the intersection of these lines. This address information is recorded in the control information storage medium 49. As described above, the short-circuited portion between the common wiring and the signal wiring on the substrate is detected for all the common wiring and the signal wiring of the liquid crystal panel 31, and the address of the short-circuiting location is obtained.
[0040]
When the address of the short part between the common wiring and the signal wiring is specified, the inspection apparatus repairs the short part by irradiating the position on the substrate indicated by the address with the laser beam. For this purpose, the control unit 43 controls the XY drive unit 39 based on the address, 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 process so that all the short-circuited portions of the addresses recorded in the control information storage medium 49 are repaired by the laser beam.
[0041]
As described above, the inspection apparatus for the liquid crystal panel according to the present embodiment can identify and repair a short-circuit portion between the common wiring and the signal wiring on the substrate of the liquid crystal panel, and can reduce line defect defects due to the short-circuit. The manufacturing yield of the array substrate can be greatly improved.
[0042]
【The invention's effect】
According to the inspection method of the present invention, when there is a short between the common wiring and the signal wiring in the liquid crystal panel, the line defect is displayed in each of the vertical and horizontal directions around the shorted portion. At this time, since the intersection of the vertical and horizontal line defects can be recognized as a short portion, the address of the short portion can be specified, and repair processing by laser irradiation or the like can be performed in a later process. As a result, it is possible to reduce line defect defects due to shorts between the wirings of the liquid crystal panel, and to greatly improve the manufacturing yield of the array substrate.
[0043]
According to the inspection apparatus of the present invention, it is possible to specify the address of the short-circuited portion on the liquid crystal panel substrate and to perform repair processing by laser beam irradiation. The manufacturing yield can be greatly improved.
[Brief description of the drawings]
FIG. 1 is a diagram showing voltage waveforms applied to 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 voltage waveforms applied to each electrode in the liquid crystal panel inspection method according to the second embodiment of the present invention;
FIG. 4 is a diagram illustrating a change in display on a liquid crystal panel when there is a defective portion in the inspection by the inspection method of 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 planar 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 is a diagram showing a voltage waveform (normal display applied voltage waveform) applied to each electrode in a conventional liquid crystal panel defect inspection method;
[Explanation of symbols]
1 Applied voltage to common wiring
2 Voltage applied to signal wiring
3 Center 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 capacity section
18 Common wiring electrode pads
19 Contact hole
20 Electrode pads for signal wiring
31 LCD panel
33 XY stage
39 XY drive unit
41 LCD display signal source
43 Control unit
45 Laser irradiation part
47 Image recognition unit

Claims (8)

It has a pair of substrates, the scanning wiring and the common wiring are arranged in parallel on one substrate, and the signal wiring is arranged orthogonal to the scanning wiring and the common wiring, and a matrix is formed at the intersection of the scanning wiring and the signal wiring. A switching element and a pixel electrode connected to a signal wiring via the switching element, and a substrate surface between the common electrode pad connected to all the common wirings in the inspection region and the pixel electrode A method for inspecting a defect of a liquid crystal panel for operating a liquid crystal by applying an electric field substantially parallel to
The voltage applied to the common electrode pad during the inspection of the liquid crystal panel is greater than the potential difference in the case where the potential difference between the common wiring potential and the average potential applied to the signal wiring is to display an image during normal operation of the liquid crystal panel. Thus, the vertical and horizontal line defects are displayed on the liquid crystal panel, and the intersection of the vertical and horizontal line defects is specified as a short-circuited portion. A method for inspecting a liquid crystal panel. 2. The method for inspecting a liquid crystal panel according to claim 1, wherein the voltage applied to the common electrode pad is an alternating voltage whose value changes with time. 3. The liquid crystal panel inspection method according to claim 2, wherein the voltage applied to the common electrode pad is any one of a rectangular wave, a triangular wave, and a sawtooth wave having a predetermined frequency. 3. The voltage period T applied to the common electrode pad satisfies T ≦ 10 × Rlc × Clc, where Rlc is a liquid crystal resistance value of one pixel and Clc is a capacitance. Inspection method for liquid crystal panels. The common electrode pad voltage is set so that a difference between an average voltage applied to the signal wiring and a voltage applied to the common wiring is equal to or greater than a threshold voltage value of a liquid crystal of the liquid crystal panel. The liquid crystal panel inspection method according to claim 1. It has a pair of substrates, the scanning wiring and the common wiring are arranged in parallel on one substrate, and the signal wiring is arranged orthogonal to the scanning wiring and the common wiring, and a matrix is formed at the intersection of the scanning wiring and the signal wiring. A switching element and a pixel electrode connected to a signal wiring via the switching element, and a substrate surface between the common electrode pad connected to all the common wirings in the inspection region and the pixel electrode A device for inspecting a defect of a liquid crystal panel that operates a liquid crystal by applying an electric field substantially parallel to
The voltage applied to the common electrode pad at the time of inspection of the liquid crystal panel is set 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 when displaying an image during normal operation of the liquid crystal panel. And a control means for displaying the line defect in the vertical direction and the horizontal direction on the liquid crystal panel and identifying the intersection of the line defect in the vertical direction and the line defect in the horizontal direction as a short-circuited location. LCD panel inspection equipment. A scanning wiring and a common wiring are arranged in parallel on one substrate, and a signal wiring is arranged orthogonal to the scanning wiring and the common wiring, and a matrix is formed at the intersection of the scanning wiring and the signal wiring. A switching element and a pixel electrode connected to a signal wiring via the switching element, and a substrate surface between the common electrode pad connected to all the common wirings in the inspection region and the pixel electrode In an apparatus for inspecting a defect of a liquid crystal panel that operates a liquid crystal by applying an electric field substantially parallel to the
  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;
  A signal source for outputting a control signal for controlling each wiring of the liquid crystal panel to a predetermined potential for inspection;
  A laser irradiation means for irradiating a laser beam for repairing the short-circuit portion;
  Driving means for driving the stage in the X and Y directions;
  The voltage applied to the common electrode pad at the time of inspection of the liquid crystal panel is set 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 when displaying an image during normal operation of the liquid crystal panel. And thereby causing the vertical and horizontal line defects to be displayed on the liquid crystal panel, and based on the display information of the liquid crystal panel at that time taken in by the image recognition means, the vertical line defects and the horizontal line defects are displayed. The intersection point with the defect is specified as a short-circuit portion of the liquid crystal panel, and the liquid crystal panel is moved to a desired position by controlling the XY driving means so that the laser beam is irradiated to the specified short-circuit portion, and the laser irradiation is performed. Control means for controlling the laser irradiation means to repair the short-circuit by means of a laser beam from the means;
An inspection apparatus for a liquid crystal panel, comprising: It has a pair of substrates, the scanning wiring and the common wiring are arranged in parallel on one substrate, and the signal wiring is arranged orthogonal to the scanning wiring and the common wiring, and a matrix is formed at the intersection of the scanning wiring and the signal wiring. The switching element and the pixel electrode connected to the signal wiring through the switching element are arranged in a shape, and are substantially parallel to the substrate surface between the common electrode pad connected to the common wiring and the pixel electrode. A method of manufacturing a liquid crystal panel in which an electric field is applied to operate a liquid crystal,
  A method for manufacturing a liquid crystal panel, comprising the step of inspecting a defect of the liquid crystal panel using the inspection method according to claim 1.

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