TWI495923B - Apparatus and method for repairing lcd panel - Google Patents

Description

Repair device and method for liquid crystal display panel

The present invention relates to a repair apparatus and method for an LCD panel. More specifically, the present invention relates to pre-testing the repair performance of the test pads of the LCD panel after performing the repair operation of the defective pixels of the LCD panel, and then repairing the defective pixels of the LCD panel, thereby making the LCD panel A repair device and method for an LCD panel with a minimized defect rate.

Background technique

Liquid crystal display (LCD) is a liquid crystal in which an intermediate substance between a solid and a liquid is injected between two glass sheets, and the arrangement of liquid crystal molecules is changed by the voltage difference between the electrodes on the upper and lower glass sheets to produce brightness and darkness. And a device that displays a digital or image using a light conversion phenomenon. In other words, the LCD is based on a video signal, and controls the transmittance of the liquid crystal, thereby displaying an image, the liquid crystal display panel having the unit cells arranged in a matrix, and controlling the transmittance of each unit cell based on the video signal. Drive circuit.

Among LCD manufacturers, the criterion for determining whether the LCD panel is defective is the number of defective pixels contained in the LCD panel. Here, the defect of the pixel is a case where various signal lines constituting the pixels of the LCD panel are likely to open. In other words, the LCD panel is formed by an array substrate, an opposite substrate, a liquid crystal layer, or the like. In the array substrate, a plurality of pixel electrodes arranged in a matrix shape are formed, and a plurality of pixel electrodes are arranged along a row of the plurality of pixel electrodes. A scan line, and a plurality of signal lines arranged along the column. For example In other words, in a plurality of signal lines, as long as a signal line is opened at a predetermined portion, the pixel is electrically open and becomes defective.

The repair of the so-called LCD panel, in order to connect the open signal lines of the defective pixels as described above, is generally performed by a chemical vapor deposition portion capable of performing a chemical vapor deposition process. The conductive material is vapor deposited on the open circuit of the line, and the signal line of the open circuit is electrically connected.

On the other hand, in order to fully grasp the defective pixels of the LCD panel, it is necessary to measure whether the pixel is electrically opened or open. For this purpose, a probe including a pin tip for transmitting and receiving electrical signals respectively contacting the electrode pads of the pixel is included. A device is necessary. Since the probe device is provided at the same time as the optical system in the device for repairing the defective pixels of most of the LCD panels, the probe device can directly determine whether the repair is successful or not while the defective device is repaired by the probe device.

However, the repair device and method of the conventional LCD panel have problems in that the repair failure caused by the chemical vapor phase vapor deposition portion is not properly operated during the actual repair process of the LCD panel, and the problem cannot be properly handled. In other words, through the wrong operation of the chemical vapor deposition section, it is not possible to properly vapor deposit a conductive substance, or even if a vapor deposition of a conductive substance cannot obtain a specific range of resistance values required for smooth electrical signal communication, The problem that the pixel is not perfectly repaired (bad repair). In particular, whether or not the repair is defective can be found only when the final inspection of the completed LCD panel is completed, and thus the productivity of the LCD panel is lowered.

Therefore, in order to solve the above problems, the present invention confirms that a test pad of a manual open conductor pattern is formed on one side of the LCD panel before repairing defective pixels of the LCD panel, and the test pad is subjected to a test repair operation. After the operation state of the chemical vapor deposition portion, the defective pixel of the LCD panel is repaired, and the repair device and method for the LCD panel having a significantly reduced defect rate of the defective pixel repair program of the LCD panel are provided as the object of the present invention. .

In order to achieve the above object, the repairing device for an LCD panel of the present invention is a device for detecting defective pixels of an LCD panel and repairing defective pixels by using a laser, characterized in that it comprises a repairing table provided with a base for placing the LCD panel. , an X-axis and a Y-axis moving device, which is disposed on the repair table, a chemical vapor deposition portion, which repairs the defective pixels and the test pad of the LCD panel, and a probe, which is coupled thereto The chemical vapor deposition part is connected to the test pad repaired by the chemical vapor deposition part, and the repair device is characterized in that the repair device is subjected to the test repair operation of the test pad of the LCD panel, and then The main repair operation is performed on the defective pixels of the LCD panel.

The chemical vapor deposition layer may include: a chamber for providing a chemical vapor deposition space required for performing a repair operation on a defective pixel of the LCD panel, and a laser portion The laser is illuminated by the space provided by the chamber, and an optical portion is controlled by the light path and focus of the laser illuminated by the laser portion.

The chamber system may include: a gas vapor deposition portion for providing a gas vapor deposition space at a predetermined portion on the defective pixel of the LCD panel, and a metal supply portion for supplying the metal particles for repair to The vapor deposition space provided by the gas vapor deposition portion, and an air curtain portion for isolating the vapor deposition space provided by the gas vapor deposition portion from the outside.

The gas vapor deposition section may further comprise a window configured to pass through the laser.

The chamber may further comprise a fuzzy gas supply providing a fuzzy gas on the surface of the window.

The repair method of the LCD panel of the present invention detects the defective pixels of the LCD panel and repairs the defective pixels by using the laser, and is characterized by the following steps: (a) the steps of testing and repairing the test pads of the LCD panel, and (b) The step of checking whether the repaired test pad is repairable, and (c) the step of performing a major repair operation on the defective pixels of the LCD panel.

This test and the main repair operation can be carried out by chemical vapor deposition.

This inspection operation can be performed by a resistance measurement method in which the probe is in contact.

This major repair operation can be performed by the best repair conditions determined by the test repair work.

According to the invention of the above configuration, after the test pad provided on one side of the LCD panel is subjected to a test repair operation, and the repair of the test pad is checked by the probe, if the test repair work is judged to be normal, , By performing a main repair operation on defective pixels of the LCD panel, there is an effect of greatly reducing the defective rate of the repair work.

Best form for carrying out the invention

Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is an exploded perspective view and a completed view showing a configuration of a repair apparatus 100 for an LCD panel according to an embodiment of the present invention, and Fig. 2 is a perspective view showing a configuration of an example of a chemical vapor deposition portion. As shown in FIGS. 1 and 2, the repair device 100 for an LCD panel includes a repair table 110, an X-axis moving portion 120 and a Y-axis moving portion 130, a base 140, a chemical vapor deposition portion 170, and a probe 180. Composition. Further, the chemical vapor deposition portion 170 includes a chamber 200, a laser portion 172, and a first optical portion 174.

First, the repair table 110 made of the angle frame made of metal is fixed to the ground without applying vibration or punching from the outside. The top of the repair table 110 is flattened to facilitate setting up the device for the program.

The both sides of the upper side and the lower side of the upper surface of the repair table 110 are provided so as to include an X-axis moving portion 120 which forms one of a linear shape and an X-axis track. The X-axis moving portion 120 is moved along the two X-axis trajectories by the driving force of a motor (not shown). Further, on the upper surface of the repair table 110, a Y-axis moving portion 130 including a Y-axis support table is also provided. The two tracks of the X-axis moving portion 120 are connected to both ends of the linear Y-axis support table. Therefore, the Y-axis support mechanism of the Y-axis moving portion 130 is provided to be movable in the X-axis direction at the upper portion of the repair table 110 by the operation of the X-axis moving portion 120.

The Y-axis moving portion 130 is provided with a chemical vapor deposition portion 170. this The chemical vapor deposition portion 170 is movable in the Y-axis direction along the Y-axis support by the driving force of the motor (not shown) and by the Y-axis moving portion 130 that operates. Here, when the chemical vapor deposition portion 170 is provided, the Y-axis support portion of the Y-axis moving portion 130 is provided with a pedestal 160 which is formed by using an angle frame or a profile of a metal material, etc., and at the same time, chemistry The vapor phase vapor deposition unit 170 is provided on the Y-axis support table of the Y-axis moving unit 130 by the pedestal 160. An example of the assembled state of the chemical vapor deposition portion 170 is exemplified in FIG.

As described above, the X-axis moving portion 120 and the Y-axis moving portion 130 are respectively operated by the driving force of the motor, and the X-axis and the Y-axis of the chemical vapor deposition portion 170 on the upper portion of the repairing table 110 can be moved.

The space provided by the two X-axis rails of the X-axis moving portion 120 provided at both ends of the repair table 110 is provided with a flat base 140 on which the LCD panel 142 is placed. As shown in Fig. 1, one LCD panel 142 is composed of a plurality of unit LCD panels, and in the final stage, the respective unit LCD panels are separated and used. This is to improve the productivity of the LCD panel. Referring to Fig. 1, in the No. 1 manufacturing process, an 8-unit LCD panel can be produced.

At this time, the base 140 is disposed at a lower position of the chemical vapor deposition portion 170 in which the Y-axis moving portion 130 is provided, and the operation of the chemical vapor deposition portion 170 is not affected. Further, on the base 140, since the LCD panel 142 to be described later is placed, even if the LCD panel 142 is placed on the base 140, the chemical vapor deposition portion 170 must be smoothly operated.

The configuration of the chemical vapor deposition portion 170 provided in the Y-axis moving portion 130 will be described in detail below.

First, a gas supply unit 150 for supplying a metal gas required for performing a chemical vapor deposition process and an inert gas for a curtain is provided in the Y-axis moving unit 130. As shown in Fig. 1, the gas supply unit 150 is disposed on the Y-axis support unit side of the Y-axis moving unit 130, and gas can be supplied to the chamber 200 to be described later without affecting the X-axis moving unit 120. Under the operation of the Y-axis moving unit 130, the gas supply unit 150 may be additionally provided outside the apparatus.

On the Y-axis moving portion 130, the chemical vapor deposition portion 170 provided on the pedestal 160 made of a metal frame or the like is provided to be movable along the Y-axis support.

A laser portion 172 is provided on the upper portion of the pedestal 160. The laser section 172 can use a pulsed laser or a continuous wave (CW) laser, and the output is also variable in response to the repair operation.

The intermediate portion of the pedestal 160 is provided with a first optical portion 174 formed by an optical mechanism such as a beam splitter, a lens, and a filter for controlling the laser beam path and the focus from the laser portion 172.

On one side of the lower stage of the pedestal 160, the probe 180 for inspecting and repairing the test pad 144 of the LCD panel 142 repaired by the chemical vapor deposition portion 170 is set to be movable by the Z-axis moving portion 182. In the up and down (Z axis) direction. The Z-axis moving portion 182 is operated by the driving force of the motor to move the probe 180 up and down. The probe 180 includes a second optical portion 181 including a probe card 184 that is in contact with the test pad 144 of the LCD panel 142, a contact state in which the probe card is observed, and the like.

Further, a chamber 200 for providing a space required for the chemical vapor deposition process at a predetermined position of the LCD panel 142 is also provided by a gas supply line connected to the gas supply unit 150 by using gas supplied from the outside. On the side of the lower section of the pedestal 160.

Figures 3A and 3B show the construction of the probe card 184. Fig. 3A is a plan view showing the configuration of the probe card 184, and Fig. 3B is a side view of the probe card 184 shown in Fig. 3A as seen from the direction A.

As shown in FIGS. 3A and 3B, the probe card 184 has a configuration in which a needle tip 186 that is in contact with the test pad 144 of the LCD panel 142 is provided at the center of the main substrate corresponding to the PCB. Although the needle tips 186 are disposed in a total of six in a row of eight, the total number of the needle tips 186 is changed according to the state of the test pads 144 of the LCD panel 142 to be inspected. The needle tip 186 has a needle shape similar to that of the "┌" mold, and the material is preferably made of a high-strength metal such as tungsten. The end of the needle tip 186 on the side in contact with the test pad 144 is preferably a round hammer or a cylindrical shape. To check for repair of the test pad 144, the other side of the tip 186 that is in contact with the test pad 144 is coupled to an external signal line (not shown).

The probe card 184 is provided with an edge sensor 188 on both sides of the opposite needle tip 186. This edge sensor 188 is used as a function of identifying whether the needle tip 186 and the test pad 144 of the LCD panel 142 are in proper contact.

Fig. 4A is a perspective view showing the configuration of the chamber 200 of the chemical vapor deposition section 170, and Fig. 4B is a partial cutaway view showing the internal structure of the chamber 200. Further, Fig. 4C is a cross-sectional view showing the configuration of the chamber 200.

The chamber 200 is formed by integrally forming a circular chamber body 210 for The mounting portion 212 is fixed to one side of the chamber body 210 on one side of the lower portion of the chemical vapor deposition portion 170. The mounting bracket 212 can easily secure the chamber 200 to one side of the pedestal 160.

In the center of the chamber body 210, a cylindrical gas vapor deposition portion 220 for providing a space required for performing a chemical vapor deposition process is formed, and above the gas vapor deposition portion 220, a gas vapor deposition is provided. The portion 220 is separated from the external atmosphere by a form 222. At this time, the laser beam irradiated from the laser portion 172 passes through the window to perform the laser chemical vapor deposition process, and the form 222 for performing the repair operation is formed of a transparent material such as quartz. It is better.

On both sides of the chamber body 210, in order to supply metal particles to predetermined portions of the LCD panel 142, a metal supply tube 214a and a metal discharge tube 214b are provided for repairing defective pixels. At this time, the metal particles supplied through the metal supply pipe 214a are preferably tungsten (W).

The metal supply pipe 214a is coupled to a metal supply port 214c formed on one side of the gas vapor deposition portion 220, and the metal discharge pipe 214b is formed with a metal discharge groove 214d formed around the gas vapor deposition portion 220 and formed in a ring shape. Connected. Therefore, it is supplied through the metal supply port 214c, and the metal particles used in the chemical vapor deposition and the by-products generated during the chemical vapor deposition are discharged to the metal discharge pipe 214b through the metal discharge groove 214d and the metal discharge pipe 214b. external.

The metal particles supplied through the metal supply pipe 214a and the metal discharge pipe 214b are not leaked to the outside on both sides of the chamber body 210, and at the same time, in order to prevent the intrusion of foreign matter contained in the outside atmosphere, the gold is formed. The inert gas of the air curtain which is a reaction of the particles is provided with an air curtain supply pipe 216a and an air curtain exhaust pipe 216b which respectively discharge the inert gas used for forming the air curtain to the outside. At this time, it is preferable to use argon (Ar) as the inert gas to be supplied.

The inert gas system supplied through the air curtain supply pipe 216a is discharged through the air curtain supply groove 216c formed on the lower side of the chamber body 210, and then recovered in the air curtain exhaust groove 216d, and then discharged to the air curtain exhaust pipe 216b to the air curtain exhaust pipe 216b. external.

The air curtain supply groove 216c and the air curtain exhaust groove 216d are respectively formed in a ring shape and are concentric with each other.

Thereby, a chemical vapor deposition process can be performed in the atmosphere by a gas jet method using an air curtain method.

Here, the air curtain supply groove 216c and the air curtain exhaust groove 216d form a concentric shape with the metal discharge groove 214d, and the gas vapor deposition portion 220 is located at the center position.

On the other hand, when the vapor deposition process is performed by the gas vapor deposition section 220, the window 222 provided on the upper side of the gas vapor deposition section 220 is also vapor-deposited, since this may hinder the passage of the laser, and therefore, in order to prevent The window 222 is vapor deposited to supply a fuzzy gas. To this end, a fuzzy gas supply pipe 218a is disposed on one side of the chamber body 210 opposite to the window 222 provided at the upper portion of the gas vapor deposition portion 220, and the ambiguous gas can be ejected.

Regarding the repair method of the LCD panel of the present invention by the repair device 100 of the LCD panel configured as described above, reference will be made to FIGS. 5 to 8 To illustrate.

After the base 140 is placed on the upper portion of the repair table 110, an LCD panel 142 formed of a plurality of unit LCD panels is disposed on the base 140.

On one side of the LCD panel 142, a test pad 144 for performing a test repair operation on defective pixels of the LCD panel 142 is formed. At this time, the test pad 144 is attached to the entire area of the LCD panel 142 to form an area to be discarded during the LCD manufacturing process.

After the LCD panel 142 is placed on the base 140, the chemical vapor deposition unit 170 is operated to repair (mainly repair) the defective pixels of the LCD panel 142.

At this time, the repair (test repair) operation of the test pad 144 formed on one side of the LCD panel 142 is preferentially performed before the main repair work is performed. Therefore, after confirming the wiring state of the test pad 144, the X-axis moving portion 120 and the Y-axis moving portion 130 are operated to move the chamber 200 directly above the test pad 144 (see FIG. 5).

Fig. 6A shows an example of a test pad 144 provided on one side of the LCD panel 142. As shown in FIG. 6A, a plurality of pairs of open signal lines a to g are formed opposite to the test pad 144. The test pad 144 is composed of all eight sets of signal lines a to g. This is the corresponding probe card 184 composed of 8 sets of needle tips 186 shown in Fig. 3A. However, as previously discussed, the number of signal lines for test pad 184 can also be varied as needed. Moreover, the number of signal lines a to g of the test pad 144 is preferably the same as the number of the needle tips 186 of the probe card 184.

After the chamber 200 is placed over the test pad 144, the chamber 200 While supplying the metal gas and the inert gas for the air curtain, the environment in which the chemical vapor deposition process is performed is performed through the gas vapor deposition portion 220 formed at the center of the chamber body 210, and the test repair operation is performed. In the chemical vapor deposition process, the laser beam emitted from the laser portion 172 is irradiated onto the portion of the chamber body 210 to be irradiated to the portion where the test pad 144 is to be subjected to the test repair operation. At this time, the laser is guided to a necessary position by the optical mechanism (beam beam splitter, lens, etc.) provided in the first optical portion 174.

Figure 6B shows the state of the test pad 144 when the test repair work is completed. As shown in Fig. 6B, by the test repair operation, in Fig. 6A, the conductive lines 146 are vapor-deposited between the open signal lines a to g, and the signal lines a to g are connected to each other. Although the type of the vapor deposition conductive material 146 is not particularly limited during the test repair process, it is preferably the same as the conductive material used in the main repair process.

On the other hand, in the test repairing operation, the chemical vapor deposition conditions of the chemical vapor deposition portion 170 are preferably different for each of the signal lines a to g of the test pad 144. This is because the resistance value of the vapor deposition-based conductive material changes due to the chemical vapor deposition conditions. Therefore, the signal line repaired by the main repair operation is the optimum resistance actually required by the LCD panel. Values are used to set optimal chemical vapor deposition conditions (eg, vapor deposition pressure, vapor deposition rate, laser intensity, laser focus distance, etc.).

Once the test repair operation is completed, as shown in FIG. 7, the Z-axis moving portion 182 is operated, and after the probe 180 is brought into contact with the test pad 144, The resistance is measured by the signal lines a to g of the test pad 144, and it is checked whether the repair of the test pad 144 is normal, and the chemical vapor deposition conditions applicable to the signal line repair showing the optimum resistance value are obtained.

Next, the defective (primary repair) operation of the defective pixels of the LCD panel 142 is performed under the same conditions as the optimum chemical vapor deposition conditions obtained in the process of Fig. 7. For this reason, the X-axis moving unit 120 and the Y-axis moving unit 130 are operated, and the chamber 200 is moved to a predetermined position of the LCD panel 142 which is the target of the main repair work (see FIG. 8). Since the operation of the chemical vapor deposition portion 170 at the time of main repair is not different from the above-described test repair, detailed description thereof will be omitted.

Therefore, in the present invention, after the test repair operation of the test pad 144 provided on one side of the LCD panel 142 is performed, the repair of the test pad 144 can be checked by the probe 180, and the optimum chemistry is obtained. Under the same conditions of the vapor phase vapor deposition conditions, the main repair operation of the defective pixels of the LCD panel can have the advantage of greatly reducing the defective rate of the repair operation. Therefore, it can be said that the present invention has high industrial applicability.

In addition, the preferred embodiments of the present invention have been described in detail, and various modifications can be made without departing from the spirit and scope of the invention. Therefore, the scope of the technology of the present invention is not limited to the embodiments described above, but should be defined by the description of the claims and equivalents thereof.

100‧‧‧LCD panel repair device

110‧‧‧Repair table

120‧‧‧X-axis moving part

130‧‧‧Y-axis moving part

140‧‧‧Abutment

142‧‧‧LCD panel

144‧‧‧ test pad

146‧‧‧ Conductive substances

150‧‧‧Gas Supply Department

160‧‧‧ pedestal

170‧‧‧Chemical Vapor Deposition

172‧‧‧Ray Department

174‧‧‧First Optical Department

180‧‧‧ probe

181‧‧‧2nd Optical Department

182‧‧‧Z-axis moving part

184‧‧‧ Probe card

186‧‧‧ needle tip

188‧‧‧Edge sensor

200‧‧‧ chamber

210‧‧‧ chamber body

212‧‧‧ Mounting bracket

214a‧‧‧Metal supply tube

214b‧‧‧Metal discharge pipe

214c‧‧‧ metal supply port

214d‧‧‧Metal drain

216a‧‧‧Air curtain supply pipe

216b‧‧‧Air curtain exhaust pipe

216c‧‧‧Air curtain supply ditch

216d‧‧‧Air curtain exhaust groove

218a‧‧‧Fuzzy gas supply pipe

220‧‧‧Gas Vapor Deposition

222‧‧‧ form

Fig. 1 is an exploded perspective view and a completed view showing the configuration of a repairing device for an LCD panel according to an embodiment of the present invention.

Fig. 2 is a perspective view showing a configuration of an example of a chemical vapor deposition section.

Fig. 3A is a plan view showing the configuration of the probe card.

Fig. 3B is a side view of the probe card shown in Fig. 3A as seen from the direction a.

Fig. 4A is a perspective view showing the constitution of a chamber of a chemical vapor deposition section.

Fig. 4B is a partial cutaway view showing the inside of the chamber of the chemical vapor deposition section.

Fig. 4C is a cross-sectional view showing the constitution of a chamber of the chemical vapor deposition section.

Fig. 5 is a view showing the constitution of a repair method of an LCD panel according to an embodiment of the present invention.

Fig. 6A is a view showing the constitution of a repair method of an LCD panel according to an embodiment of the present invention.

Fig. 6B is a view showing the constitution of a repair method of an LCD panel according to an embodiment of the present invention.

Fig. 7 is a view showing the constitution of a repair method of an LCD panel according to an embodiment of the present invention.

Fig. 8 is a view showing the constitution of a repair method of an LCD panel according to an embodiment of the present invention.

100‧‧‧LCD panel repair device

110‧‧‧Repair table

120‧‧‧X-axis moving part

130‧‧‧Y-axis moving part

140‧‧‧Abutment

142‧‧‧LCD panel

144‧‧‧ test pad

150‧‧‧Gas Supply Department

160‧‧‧ pedestal

180‧‧‧ probe

200‧‧‧ chamber

Claims (9)

A liquid crystal display (LCD) panel repairing device for detecting defective pixels of an LCD panel and repairing defective pixels by using a laser, comprising: a repairing table provided with a base for placing an LCD panel; X-axis and Y a shaft moving device disposed on the repair table; a chemical vapor deposition portion for repairing defective pixels and test pads of the LCD panel; and a probe coupled to the chemical vapor deposition Connected to the test unit to check whether the test pad repaired by the chemical vapor deposition part is repaired, and the chemical vapor deposition part is subjected to a test repair operation on the test pad of the LCD panel, and then the LCD panel is The defective pixel performs a main repairing operation, and the aforementioned test pad is formed on one side of the aforementioned LCD panel. The repair device of the LCD panel of claim 1, wherein the chemical vapor deposition portion comprises: a chamber for providing a chemical vapor phase required for repair work on defective pixels of the LCD panel. a vapor deposition space; a laser portion that illuminates the laser through a space provided by the chamber; and an optical portion that controls the light path and focus of the laser irradiated by the laser portion . The repair device for an LCD panel of claim 2, wherein the chamber comprises: a gas vapor deposition portion for providing a gas vapor deposition space at a predetermined portion of the defective pixel of the LCD panel; a metal supply portion for supplying metal particles for repair to the gas vapor deposition portion a vapor deposition space provided; and a curtain portion for isolating the vapor deposition space provided by the gas vapor deposition portion from the outside. The repairing device for an LCD panel of claim 3, wherein the gas vapor deposition portion further comprises a window configured to pass through a laser. The repair device of the LCD panel of claim 4, wherein the chamber further comprises a fuzzy gas supply portion for providing a fuzzy gas on the surface of the window. A method for repairing a liquid crystal display (LCD) panel, which detects defective pixels of an LCD panel and repairs defective pixels by using a laser. The repairing method comprises the following steps: (a) steps of testing and repairing the test pads of the LCD panel (b) a step of inspecting or repairing the repaired test pad; and (c) performing a major repair operation on the defective pixels of the LCD panel. The repair method of the LCD panel of claim 6, wherein the test and the main repair operation are performed by chemical vapor deposition. For example, the repair method of the LCD panel of claim 6 of the patent scope, wherein The inspection operation is performed using a resistance measurement by probe contact. For example, the repair method of the LCD panel of claim 6 is performed by the optimum repair condition determined by the test repair operation.