TWI706559B - Method and apparatus for repairing hot pixel defect in liquid crystal dispaly - Google Patents

Abstract

Disclosed herein is a technology for repairing a hot pixel defect in a liquid crystal display (LCD). A method of repairing a hot pixel defect in an LCD is a method of repairing a brightness defect in the LCD by blackening a defective pixel through laser beam radiation. The method includes a first step of forming a periphery corresponding to the edge of the defective pixel into a barrier rib of a hardened state by radiating a laser beam of first intensity to the periphery and a second step of blackening the central part of the defective pixel surrounded by the periphery by radiating a laser beam of second intensity stronger than the first intensity.

Description

Method and equipment for repairing hot pixel defects in liquid crystal display [Cross Reference of Related Applications]

This application claims the rights and interests of Korean Patent Application No. 10-2018-0118941 filed with the Korean Intellectual Property Office on October 5, 2018, the entire content of which is incorporated herein by reference.

The present invention relates to a technique for repairing a hot pixel defect in a liquid crystal display (LCD), and more specifically, it relates to a technique for repairing a hot pixel defect that can make a corresponding pixel become black at the same time. A method and device that does not give an adverse effect to an adjacent pixel when a hot pixel defect exists in a specific position of an LCD.

Generally speaking, in an LCD, which is an active matrix method, a liquid crystal layer operates as an optical switch by changing a liquid crystal array by applying a voltage to each pixel, so that the light transmittance of the liquid crystal layer changes, by This implements an image.

1, a liquid crystal panel 500 has a structure in which a color filter substrate 530 (that is, the upper substrate) and a TFT array substrate 510 (that is, the lower substrate) are coalesced to face each other, and have a dielectric An anisotropic liquid crystal layer 520 is formed between the upper substrate and the lower substrate. The liquid crystal panel is driven in this way by driving a TFT attached to hundreds of thousands of pixels through an address line for pixel selection to apply a voltage to a corresponding pixel.

In this case, the color filter substrate 530 includes glass 531, color filters 532 such as RGB, a black matrix 533 formed between the color filters 532, an outer coating 534, and a common electrode. One is indium tin oxide (ITO) film 535 and oriented film 536. A polarizer 537 is attached to the top of the glass.

In order to manufacture the liquid crystal panel, a TFT array substrate manufacturing process, a color filter substrate manufacturing process, and a liquid crystal cell manufacturing process must be performed. The TFT array substrate manufacturing process is a process of forming gate lines, data lines, TFTs and pixel electrodes on a glass substrate by repeating deposition and photolithography processes on the lower substrate.

The color filter substrate manufacturing process is to fabricate RGB color filters arranged in a substrate (generally, the upper substrate) that has formed a black matrix in a given sequence to implement colors and then form ITO for a common electrode One of the thin film processes.

The liquid crystal cell manufacturing process is a process of coalescing the TFT array substrate and the color filter array substrate to maintain a specific gap therebetween and forming a liquid crystal layer by injecting liquid crystal into the gap. Recently, a drop-in injection (ODF) process of uniformly coating the TFT array substrate with liquid crystal and then coalescing the TFT array substrate and the color filter substrate is disclosed.

In a process of testing the liquid crystal display device, a test pattern is displayed on the screen of the liquid crystal panel, and it is detected whether there is a defective pixel. If there is a defective pixel, the task for repairing the defective pixel is performed. The defects of liquid crystal panels can be basically classified into point defects, line defects and display irregularities. Point defects occur due to defects in TFT elements, pixel electrodes, or color filter lines. Line defects are caused by disconnection or short-circuiting between lines, destruction of TFTs attributable to static electricity, or connection failure of the driving circuit. Due to the irregularity of the cell thickness, the irregularity of the liquid crystal orientation, the distribution of TFTs at a specific place and the relatively large time constant of the lines, display irregularities can occur.

Among them, point defects and line defects are mainly due to defects in the line. In a conventional technology, when a disconnected line is detected, the disconnected part is connected, and in the case of a short circuit, the corresponding line is disconnected.

In addition to these defects, in the process of manufacturing liquid crystal panels, impurities including dust, organic materials or metals are adsorbed. If these impurities are adsorbed near the color filter, the corresponding pixel may cause the phenomenon that it generates much brighter light than the normal pixel when driving the panel.

As described above, when a defect occurs in the driving of the switch for a reason (such as the patterning of the source and drain electrodes forming a switching element is not usually performed), hot pixels or dead pixels may occur. The human eye is more sensitive to hot pixels that appear in the dark state than to bad pixels that appear in the bright state. Therefore, when determining a defect in a liquid crystal panel, the criterion will be stricter than that applied to the defect in the dead pixel Applied to defects in hot pixels. Therefore, there is a need for a method for minimizing the panel error rate attributable to hot pixels. For this purpose, a method of changing hot pixels into dead pixels is proposed.

A laser repair method is widely used to change hot pixels into dead pixels. FIG. 2 is a conceptual diagram showing an example of performing laser repair on a pixel to be processed for the blackening task using a scanning method. As shown in FIG. 2, in the prior art, all pixel regions including the peripheral and central portions of the pixels are processed by a laser beam having the same intensity. Generally speaking, the scanning direction SC0 of the laser beam is the Z-shaped direction. In order to perform the blackening faithfully, it is necessary to irradiate a laser beam to the periphery of the formed black matrix in addition to the part of the pixel electrode of the pixel to be processed.

However, due to the strong energy laser in the laser repair process, free radicals can be generated, thereby generating chain reactions of the materials forming the color filter layer and the liquid crystal layer in the display panel. Therefore, in addition to the corresponding pixel area, the voltage holding ratio (VHR) of the adjacent pixel area is also reduced, so the brightness can be reduced.

FIG. 3 shows a phenomenon in which an abnormality of the liquid crystal array is scattered in the form of bubbles in a pixel similar to the pixel P0 adjacent to the reception processing and the abnormality appears as a black stain (BS). The enlarged view of FIG. 3 shows that the pixel with a black stain after the laser repair process for the defective pixel is indicated as the point BS1.

Regarding the abnormality and repair of this LCD, Japanese Patent Application Publication No. 2006-72229 discloses a method of impairing the array characteristics of liquid crystal by irradiating a laser to a directional film to damage the oriented film and reducing the transmittance of the liquid crystal to light. Technology to remove the appearance of light seepage.

As another repair method, Korean Patent Application No. 10-2006-0086569 on a blackening processing method for defective pixels using a femtosecond laser is disclosed.

Korean Patent No. 10-0879010 discloses a method of using a laser beam of a specific wavelength according to the block shooting method or the scanning method to blacken the organic materials of the respective colors used to form the color filter layer of the LCD.

Korean Patent No. 10-1226711 discloses a pixel configuration divided into two parts of an S-PVA mode LCD (that is, a type of vertical oriented liquid crystal mode with a Vcom line and an ITO line pattern).

However, the conventional blackening processing technology of using lasers for defective pixels has a problem in that during the blackening process, it has an adverse effect on the pixels around the defective pixels.

An object of the present invention is to provide a method for repairing a hot pixel defect in an LCD, which can prevent a defect from being applied to an adjacent pixel in the process of repairing one of the defective pixels regarding the blackening of a defective pixel. Adverse effects.

Another object of the present invention is to provide a method and apparatus for repairing a hot pixel defect in an LCD, which can prevent and suppress the following problem: a state of a liquid crystal array appears in a pixel adjacent to a pixel of processing The anomaly spreads in a form similar to a bubble and is regarded as a stain in a display device.

Another object of the present invention is to provide a method and apparatus for repairing a hot pixel defect in an LCD, which can suppress and prevent a vertical orientation mode LCD (such as patterned vertical alignment (PVA) ) Or Super PVA (S-PVA)) is one of the characteristics and advantages of the problems that occur in the state of the liquid crystal array of adjacent pixels.

In one aspect of the present invention, a method of repairing a hot pixel defect in a liquid crystal display (LCD) is to repair a brightness defect in the LCD by blackening a defective pixel through laser beam radiation Methods. The method includes a first step of forming a barrier barrier in a hardened state by radiating a laser beam of a first intensity to a periphery corresponding to the edge of the defective pixel, and by radiating A second step of blackening the central part of the defective pixel surrounded by the periphery by a laser beam of a second intensity stronger than the first intensity.

In another aspect of the present invention, an apparatus for repairing a hot pixel defect in a liquid crystal display (LCD) is an apparatus for repairing the LCD by blackening a defective pixel through laser beam radiation One of the devices with defective brightness. The device includes: a laser radiation unit configured to generate a laser beam; a task unit on which an LCD is placed or fixed; an actuator positioned on the laser radiation unit and the task One or more of the units to change the relative position of a laser beam radiated to a defective pixel of the LCD; and a controller configured to control an operation of the actuator and the laser One of the radiation units is operated. The controller radiates a laser beam of a first intensity to a periphery corresponding to the edge of the defective pixel, and radiates a laser beam of a second intensity stronger than the first intensity to a laser beam surrounded by the periphery The central part of the defective pixel.

20: Defective pixels

20a: sub-pixel

20b: sub-pixel

21: Surrounding

22: central part

24: ITO pattern

25: LCD

26: pixel electrode

27: Common electrode

30: Laser welding

32: Welding area

100: equipment

110: Controller

120: storage unit

121: Laser Management Module

122: Actuator control module

123: Laser beam intensity adjustment module

124: Information Acquisition Module

125: Scanning direction determination module

126: Welding processing module

127: Peripheral enhanced processing module

140: Laser radiation unit

150: monitoring device

160: Actuator

500: LCD panel

510: TFT array substrate

520: liquid crystal layer

530: Color filter substrate

531: glass

532: Color filter

533: black matrix

534: outer coating

535: indium tin oxide (ITO) film

536: Oriented film

SC0: scan direction

P0: pixel to be processed

P2: Repaired pixels

BS: black stain

BS1: point

SC: Scan

SC1: Scan

SC2: Scan

w1: width

w2: width

Figure 1 is a cross-sectional view showing the configuration of a conventional LCD.

Fig. 2 is a conceptual diagram showing a method for repairing defective pixels of a conventional LCD using a laser beam.

FIG. 3 is a photo for explaining the problem according to a repair method (such as the method of FIG. 2).

4 is a flowchart showing a method for repairing a hot pixel defect in an LCD according to an embodiment of the invention.

Fig. 5 is a diagram showing a laser beam of weak intensity radiated to the periphery of a defective pixel to be repaired in an LCD and a laser beam of strong intensity radiated to the defective pixel to be repaired according to the repair method of Fig. 4 A conceptual diagram of an example of the central part.

FIG. 6 is an exemplary diagram of a part of the LCD screen including pixels that have been blackened by the repair method of FIG. 4.

FIG. 7 is a diagram showing various forms of the scanning direction of the strong laser beam in the repair method of FIG. 4.

FIG. 8 is a flowchart showing a method for repairing a hot pixel defect in an LCD according to another embodiment of the present invention.

9 and 10 are flowcharts for explaining modified examples of the repair method of FIG. 8.

11 and FIG. 12 are exemplary diagrams showing the state of performing welding on the Vcom and ITO lines of the defective pixel to be repaired in the repair method of FIG. 8.

FIG. 13 is a diagram for explaining a method for repairing a hot pixel defect in an LCD according to another embodiment of the present invention.

14 is a block diagram of an apparatus for repairing a hot pixel defect in an LCD according to another embodiment of the present invention.

Detailed embodiments of the present invention will be described in detail with reference to the accompanying drawings.

4 and 5, in the method for repairing a hot pixel defect in an LCD according to the present embodiment (hereinafter referred to as the hot pixel defect repair method), firstly, a laser beam is irradiated to the defective pixel to be repaired The peripheral area or periphery 21 (S41 in Figure 4). Scanning SC1 of the laser beam in the periphery can be performed in various ways, such as clockwise or along the periphery of the defective pixel Scanning is performed counterclockwise (as indicated by the arrow in Figure 5(a)) to form a fully circular curve at the same time, or a laser beam radiates between the two long sides and two short sides of the defective pixel or the radiation periphery Part (for example, only two long sides).

In this case, the laser output is smaller than the laser beam output used for repair radiated to all pixels in the conventional technology as shown in FIG. 2, for example, it is about 30% to 80% compared with the conventional technology. More preferably, it is about 40% to 60%. If the output of the laser beam is too small, there may be light bleeding through the periphery, because the color filter layer or the directional film is carbonized or degraded to blacken it. If the laser beam output is too large and close to 100%, the adjacent pixels may be partially blackened, because the color filter layer or the directional film used for the adjacent pixels is degraded, or the laser beam is radiated to the periphery. In, the rupture expands.

In this embodiment, the width w1 of the periphery refers to the width of the outer border of one pixel in the width direction, and the width w2 of the periphery refers to the width of the outer border of one pixel in the length direction. In this case, if the peripheral widths w1 and w2 are too small, when the center part is repaired by laser, it is difficult to sufficiently block the influence on adjacent pixels. If the peripheral widths w1 and w2 are too large, there is a good possibility that light leakage may occur through the corresponding part because blackening is not sufficiently performed in the corresponding part.

By the radiation from the weak laser beam to the periphery, a polyimide film forming the oriented film on the periphery of a target pixel can be hardened to a certain extent, but serious damage such as cracking will not occur. In addition, when performing this processing, the impact on a pixel area close to the periphery can be minimized because the periphery is processed by a weak laser beam.

Next, in the state where the weak laser beam has been radiated to the periphery 21 of the pixel (as shown in FIG. 5(a)), a laser beam is radiated to the center portion 22 of the corresponding pixel, that is, different from the periphery Or the area surrounded by the periphery, as shown in Figure 5(b) (S42 in Figure 4). In this process, the organic material is carbonized or degraded in the part of the color filter layer and the directional film to which the laser beam has been irradiated. Therefore, because the optical transparency deteriorates and the characteristics of the oriented film change, the state of the liquid crystal array of the processed portion changes. As a result, the beam changes to a blackened state where the beam does not pass through one of the pixels.

The scanning SC2 of the laser beam in the central portion 22 of the pixel to be processed (ie, the defective pixel 20) can be performed up and down in a Z-shape. According to the hot pixel shortage according to this embodiment The trap repair method can perform repair processing, and has no adverse effects on the pixels adjacent to the repaired pixel P2, as shown in FIG. 6.

Next, referring to FIG. 7(a) to FIG. 7(h), the scanning SC of the laser beam for the pixel to be processed that can be used in the thermal pixel defect repair method according to this embodiment can be performed in various forms.

For example, in order to completely radiate a laser beam to all pixel areas, as shown in FIG. 7, by considering the form and size of the laser beam in various ways, the laser beam is scanned in the left and right width directions or up and down within one pixel. The beam, but each scan left and right or up and down, the laser beam can be moved up and down or left and right at a specific interval.

The most effective method among these scanning methods can be selected by considering the form and size of the pixel and the internal structure of the pixel, and the selected method can be used to radiate a laser beam. Generally speaking, depending on the rotation state of the LCD stage, the scanning direction is left and right or up and down, but it can be a diagonal direction, such as the ITO line described.

In this case, the scanning trace of the laser beam can be formed by a relative movement between the laser beam and the LCD. More specifically, it is possible to adjust the angle or position of a light source or optical element (such as a mirror or beam splitter on the corresponding path) of the radiation laser beam, or the position of the LCD on the xy plane. Adjust to form the scanning trace of the laser beam. These detailed adjustment methods are well known in the art, and therefore detailed descriptions thereof are omitted.

In the process of radiating the laser beam, when the laser beam has a strong intensity, cracks may occur in the directional film. Due to the nature of the oriented film itself, this rupture can extend to the surrounding environment, just as a crack in glass extends to the surrounding environment. However, in this embodiment, when processing the central part, the energy of the laser beam is blocked and does not extend to the periphery of the pixel to be processed, because the periphery of the pixel has been hardened to change the properties of the oriented film.

As a result, the blackening is performed only in the corresponding pixels, the oriented film is broken in the adjacent pixels, the array of the liquid crystals of the adjacent pixels does not change, and the brightness reduction phenomenon attributable to the partial blackening is in the adjacent pixels Does not appear in.

Referring to FIG. 8, the device for repairing a hot pixel defect in an LCD for implementing the method for repairing a hot pixel defect in an LCD according to this embodiment is hereinafter referred to as a hot pixel defect repairing device). The shape inside determines the laser scanning direction and intensity (S81).

Next, the hot pixel defect repairing device may use the laser beam of the first energy to scan the edge portion of the laser processing area, that is, the periphery corresponding to an edge (S82).

Next, the thermal pixel defect repairing device may use a laser beam with a second energy greater than the first energy to scan the inner part of the laser processing area, that is, the central part surrounded by the periphery (S83).

Next, the thermal pixel defect repairing device may short-circuit a power electrode pattern in the pixel included in the laser processing area through laser welding (S84).

As shown in FIG. 9, the short-circuiting step S84 can be performed before the step S83 of scanning the center part with the laser beam.

In addition, as shown in FIG. 10, the short-circuiting step S84 can be performed before the step S82 of scanning the periphery with the laser beam, or can be performed before the step S81 of determining a laser scanning direction and intensity based on the shape in the pixel.

According to this embodiment, the circuit portion of the lower substrate is radiated by a laser beam having an intensity greater than the intensity of the laser beam in the step of scanning the peripheral or central portion of the defective pixel. Therefore, the circuit is disconnected in the corresponding part, or in the part where the upper layer circuit and the lower layer circuit overlap, the organic material forming the interlayer dielectric film is volatilized or carbonized, thereby short-circuiting the upper layer circuit and the lower layer circuit. As a result, pixel blackening can be performed in a dual or redundant manner because an illumination voltage signal is not properly induced into the defective pixel, and therefore the defective pixel is not turned on by the illumination signal.

For example, as shown in FIG. 11, a TFT substrate includes a pixel electrode 26 and a common electrode 27 and a liquid crystal 25 disposed between the pixel electrode and the common electrode in an LCD, which is blocked by laser welding 30 The electrical connection of the pixel electrode 26 or the common electrode 27 in a defective pixel is broken.

For another example, in the case of the S-PVA method LCD, a soldering area 32 that divides two sub-pixels 20a and 20b forming one pixel intersects and connects and intersects an ITO pattern 24 indicated in an oblique form One form of welding area 30 is shown as an example in FIG. 12.

That is, in this embodiment, it can be added by changing a common power line (Vcom line) and a transparent electrode (ITO line) in the defective pixel so that the laser welding process cannot be used. The step of driving the state of the pixel to improve the degree of blackening of the pixel, thereby significantly increasing the repair process success ratio of a defective pixel with a hot pixel defect. In this case, X-Y-θ slits can be used to form a laser shot form of laser welding.

According to this embodiment, in a defective pixel, blackening according to the radiation of the laser beam is usually performed, and blackening through the interruption of circuit signals is also performed, so the blackening process is stably completed. At the same time, through the radiation of the low-intensity laser beam, the periphery of the defective pixel is degraded, and thus acts as a barrier to prevent the organic material from rupturing and spreading toward the periphery according to the strong-intensity laser beam in the next step. Therefore, it can effectively prevent the phenomenon that the liquid crystal array of adjacent pixels is disturbed and the brightness decreases when the illumination signal is applied.

In the foregoing embodiment, it has been described that the laser beam of weak intensity is first radiated to the periphery of the target pixel, and then the circuit system blocking process for cutting or welding the circuit part of the target pixel by radiating a strong laser beam is performed . In some embodiments, the circuit system blocking process does not exist, or may be performed first, or may be performed between the step of radiating the weak laser beam to the periphery and the step of radiating the strong laser beam to the central part.

The method of repairing a hot pixel defect in an LCD according to the present embodiment can be further implemented for relatively improving the periphery 21 after the central portion 22 of the defective pixel 20 is blackened by processing it with a laser beam. One of the weakening or turbid blackening steps to strengthen the surrounding blackening. Fig. 13(a) illustrates the state of a pixel before the peripheral blackening enhancement step, and Fig. 13(b) illustrates the state of a pixel after the peripheral blackening enhancement step.

The step of enhancing the blackening of the periphery may include performing a laser scan of the periphery again using a laser beam of the first intensity or less in a form that is the same as or similar to that of the periphery. The first intensity (for example, 10 μW or less) can be used to quickly perform laser beam scanning for peripheral blackening enhancement in a very short time.

According to this embodiment, the device for repairing a hot pixel defect in an LCD can scan the periphery 21 again by using a laser beam having a third intensity equal to or less than the first intensity after the central portion 22 is blackened. (That is, by processing the periphery 21 secondly), the blackening of the periphery 21 is enhanced. This peripheral blackening enhancement process can be used to effectively deal with the minimal light leakage state in the periphery during the hot pixel defect repair process, which is seen in defective pixels processed with a probability of less than about 10%.

Referring to FIG. 14, the apparatus 100 for repairing a hot pixel defect in an LCD according to this embodiment includes a controller 110 and a storage unit 120, and can be connected to a laser radiation unit 140, a monitoring device 150 and Actuator 160. In a broad sense, the thermal pixel defect repairing apparatus 100 may include a laser radiation unit 140, a monitoring device 150, and an actuator 160.

The controller 110 executes a program stored in the storage unit 120. The controller 110 may be implemented by a central processing unit or a processor.

The storage unit 120 can store a program for implementing a method of repairing a hot pixel defect in an LCD. In addition, the storage unit 120 can store a program for controlling the operation of a device for repairing a hot pixel defect in an LCD. The program may include a software module.

The software module may include a laser management module 121, an actuator control module 122, a laser beam intensity adjustment module 123, an information acquisition module 124, a scanning direction determination module 125, and a welding processing module Group 126 and a peripheral enhancement processing module 127.

The laser management module 121 manages the operation of a laser radiation unit for radiating a laser beam. The actuator control module 122 is positioned in a task unit or a laser radiation unit that places or fixes an LCD, and operates to change or control the relative position of a laser beam radiated to defective pixels of the LCD. When performing laser scanning on the periphery of the defective pixel, the laser beam intensity adjustment module 123 adjusts the intensity of the laser beam to the first intensity (or first light intensity), and when performing laser scanning on the central part of the defective pixel During laser scanning, the intensity of the laser beam is adjusted to a second intensity (second light intensity) greater than the first intensity.

The information acquisition module 124 acquires information for determining the scanning direction and intensity of the laser beam depending on the state of a pixel before the laser scanning. The information acquisition module 124 can obtain information about the form in a defective pixel from the monitoring device 150 connected to the laser radiation unit 140 or a storage device (not shown or 120) connected to the monitoring device 150 to store the collected information.的信息。 Information. The scanning direction determination module 125 can determine the scanning direction and intensity of the laser beam for a corresponding defective pixel by comparing the information obtained by the information acquisition module 124 with the previously stored reference information.

The welding processing module 126 blocks the power line pattern in a defective pixel by welding with a laser beam. The welding processing module 126 can be implemented to radiate the laser beam of the second light intensity to the periphery of the defective pixel before radiating the laser beam of the first light intensity to the periphery of the defective pixel At least one welding process is performed in at least one of the processes before the side and after the laser beam of the second light intensity is irradiated to the periphery of the defective pixel.

After using laser scanning to blacken the central part of the defective pixel, the peripheral enhancement processing module 127 controls the laser scanning to use a laser beam with a third intensity equal to or less than the first intensity for the periphery Operate to improve the surrounding turbidity and blackening state to strengthen the surrounding blackening of defective pixels.

The laser radiation unit 140 is provided to radiate a laser beam to an LCD positioned on the task unit. The laser radiation unit 140 may include a laser generator, an optical system, and so on.

The monitoring device 150 is positioned near the task unit to sense the internal state of a specific pixel of the LCD. The monitoring device 150 may include a lighting device, a camera device, and so on.

The actuator 160 is positioned in the task unit or the laser radiation unit, and is controlled by the controller. The actuator 160 may include at least one device selected from a motor, a piston, a pump, a valve, and a pneumatic device.

As described above, according to this embodiment, the apparatus 100 for repairing a hot pixel defect can effectively make an LCD (in particular, an LCD with a vertical orientation mode (VA MODE) in the pixel) one of Hot pixels turn black.

According to an embodiment of the present invention, it is possible to suppress and prevent the liquid crystal array of adjacent pixels caused by the radiation of the laser beam during the process of repairing the defective pixel by radiating the relatively weak laser beam to the periphery of the defective pixel. The influence of the adverse effects of the state.

According to an embodiment of the present invention, it is possible to suppress and prevent problems that occur in the normal operation of adjacent pixels in a vertical orientation mode LCD, such as patterned vertical alignment (PVA) or Super PVA (S-PVA), in which when a defective pixel is repaired by laser, the problem is easily spread to the state of the liquid crystal array of adjacent pixels.

Claims (13)

A method for repairing a hot pixel defect in a liquid crystal display (LCD) in a method of repairing a brightness defect in a liquid crystal display (LCD) by blackening a defective pixel through laser beam radiation, the method includes: A first step of forming a barrier barrier in a hardened state by radiating a laser beam of a first intensity to a periphery corresponding to an edge of the defective pixel; and A second step of a strong laser beam of a second intensity to blacken a central part of the defective pixel surrounded by the periphery. The method of claim 1, wherein the first intensity is 30% to 80% of the second intensity. The method of claim 1, further comprising before the first step, obtaining information about the monitoring device from a laser radiation unit connected to a laser radiation unit for supplying the laser beam or from a storage device connected to the monitoring device A step of determining the scanning direction and intensity of the laser beam based on the information of the internal form of a defective pixel and the obtained information. The method of claim 1, further comprising blocking a power line pattern in the defective pixel by welding according to the laser beam before the first step, before the second step, or after the second step One step. The method of claim 4, wherein the power line pattern is at least one of a common power (Vcom) electrode line and a transparent electrode in the defective pixel overlapped as an upper and a lower layer area. The method of claim 1, further comprising processing the periphery by laser scanning of a laser beam having a third intensity equal to or less than the first intensity after the second step to enhance the periphery The one step to turn black. The method according to any one of claims 1 to 6, wherein the LCD has a vertical orientation mode (VA MODE) liquid crystal in one pixel. An apparatus for repairing a hot pixel defect in a liquid crystal display (LCD) in an apparatus for repairing a brightness defect in a liquid crystal display (LCD) by blackening a defective pixel through laser beam radiation, The device includes: a laser radiation unit configured to generate a laser beam; a task unit on which an LCD is placed or fixed; An actuator positioned in one or more of the laser radiation unit and the task unit to change a relative position of a laser beam radiated to a defective pixel of the LCD; and a controller, which Configured to control an operation of the actuator and an operation of the laser radiation unit, wherein the controller radiates a laser beam of a first intensity to a periphery corresponding to an edge of the defective pixel, And radiating a laser beam of a second intensity stronger than the first intensity to a central part of the defective pixel surrounded by the periphery. Such as the device of claim 8, wherein the first intensity is 30% to 80% of the second intensity. Such as the device of claim 8, wherein before radiating the laser beam of the first intensity, the controller obtains information about the existence from a monitoring device connected to the laser radiation unit or a storage device connected to the monitoring device Information of an internal form of a defective pixel, and a scanning direction and intensity of the laser beam are determined based on the information. The device of claim 8, wherein before radiating the laser beam of the first intensity, before radiating the laser beam of the second intensity or after the laser beam of the second intensity, the controller is based on The laser beam blocks a power line pattern in the defective pixel through welding. The device of claim 8, wherein after radiating the laser beam of the second intensity, the controller performs laser on the periphery by using a laser beam having a third intensity equal to or less than the first intensity Scan to intensify the blackening of the periphery. The device of any one of claims 8 to 12, wherein the LCD includes an LCD in which a vertical orientation mode (VA MODE) liquid crystal is arranged in a pixel.

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