KR100404983B1 - Method for manufacturing liquid crystal display and liquid crystal display device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display device, a liquid crystal display device, and a laser repair device, and an object thereof is to provide a method for manufacturing a liquid crystal display device capable of repairing various defective pixels such as bright spot defects, and the like. In the manufacturing method of the display device, a step of selecting the switching element connected to the pixel and connecting the pixel to the switching element in which at least two of each pixel is provided corresponding to the defective pixel, It is characterized by including the process of irradiating a laser beam at least to alter the alignment film.

Description

Manufacturing method of liquid crystal display device and liquid crystal display device {METHOD FOR MANUFACTURING LIQUID CRYSTAL DISPLAY AND LIQUID CRYSTAL DISPLAY DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display device obtained by repairing a defective portion (defective pixel) of a surface screen by irradiating laser light, a liquid crystal display device, and a laser repair device used in the method for manufacturing the liquid crystal display device.

Recently, a liquid crystal display (LCD: Liquid Crystal Display) having low power consumption, thinness, and light weight has been widely used as a display device for a personal computer, a word processor, or the like. Among them, for example, an active matrix liquid crystal display device using a thin film transistor (TFT: thin film transistor) made of amorphous (amorphous) silicon (a-Si) foil as a switching element corresponding to a pixel is a polypixel. It is used as a full-color television or an OA display device because it has little deterioration in contrast and response, and halftone display is possible.

By the way, this TFT is formed on the array substrate and charges and discharges electric charges to the pixel electrodes constituting the pixel to generate a potential difference between the array substrate and the opposing substrate and to adjust the arrangement of liquid crystal molecules for displaying an image. In recent years, as the display portion of a liquid crystal display device has become large or fixed, the number of pixels exceeds several million to one million. In other words, it is very difficult to manufacture a display without causing defects in the pixel, and the pixel electrode is not normally formed or the foreign matter is interposed between the array substrate and the opposing substrate. There is a problem that a defective pixel is generated due to an irrationality such as not being able to apply the correct voltage to the pixel electrode, so that a normal screen cannot be displayed.

In order to repair such a defective pixel, a method in which an alignment film is processed using a laser beam to reduce the transmittance and reflectance of a pixel and is modified so that it appears to be free from defects is disclosed in, for example, Japanese Patent Application Laid-Open No. 60-243635. Japanese Patent Laid-Open Publication No. 5-297387, Japanese Patent Laid-Open No. 5-313167, Japanese Patent Laid-Open No. 7-225381, Japanese Patent Laid-Open No. 8-15660, Japanese Patent Laid-Open No. 9-258155, etc. (This method is collectively referred to as the first conventional example).

Further, a method of repairing a defective pixel by applying a DC voltage and applying a DC voltage for preserving the operation of the TFT is also described in, for example, Japanese Patent Laid-Open Nos. 63-136076 and 2-3023. , Japanese Patent Application Laid-Open No. 9-80470, Japanese Patent Application Laid-Open No. 10-104648, Japanese Patent Application Laid-Open No. 10-232412, Japanese Patent Application Laid-Open No. 10-319438, and the like. ).

In addition, Japanese Patent Application Laid-Open No. 5-210111 also discloses a method in which a gate electrode and a drain electrode of a defective portion are directly connected through a semiconductor layer or an interlayer insulating film to apply a DC voltage by using a laser beam to repair the defective pixel. (This method is referred to as a third conventional example).

However, according to the first conventional example, the probability of success of the irradiation of the laser beam itself is high (90% or more), but the mechanism for repairing the defective pixel is not sufficiently disclosed, so that the energy of the laser beam is excessively applied to damage the liquid crystal display device or The modified pixel does not operate and becomes black (in the case of the normally white mode), and the product specification in which the transmittance and reflectance of the light in the defective pixel are set in advance may not be cleared.

In addition, according to the second conventional example, high display quality can be ensured, but since fine work is required, the probability of success of the irradiation of the laser beam itself becomes low. This is effective for repairing defective pixels due to TFT malfunction, but not effective for defects due to TFTs or wiring not being formed normally, or for defects caused by foreign matter caught between the array substrate and the opposing substrate. . For that reason, the probability of successful repair of the defective pixel was generally low (about 30-50%).

Further, according to the third conventional example, the ions present with the liquid crystal molecules are accumulated in the pixel electrode corresponding to the defective pixel by the DC voltage applied to the pixel electrode, thereby shortening the lifespan of the liquid crystal display device.

SUMMARY OF THE INVENTION The present invention has been made based on the above circumstances, and an object thereof is to actively use a mechanism for repairing defective pixels and between defects and array substrates and opposite substrates due to the fact that TFTs and wiring are not normally formed. Corresponding to defects caused by foreign matter trapping and suppressing the accumulation of ions in the pixel electrode corresponding to the defective pixel, the method for manufacturing a liquid crystal display device and the laser for use in the method for manufacturing the liquid crystal display device To provide a repair device.

1 is a plan view showing a liquid crystal display of the present invention;

2 is a cross-sectional view taken along the line Y-Y 'of FIG. 1 showing the liquid crystal display device of the present invention;

3 is a schematic configuration diagram showing an entire liquid crystal display of the present invention;

4A and 4B are perspective views illustrating a display principle of the liquid crystal display device of the present invention;

5 is a schematic configuration diagram showing the entirety of the laser repair apparatus of the present invention;

6 is a graph showing the relationship between the applied current to the LD of the present invention and the pulse width of the laser light, and the relationship between the applied current to the LD and the energy with the laser light;

7 is a cross-sectional view showing an irradiation state of laser light in the method of manufacturing a liquid crystal display device of the present invention;

8 is a perspective view showing an outline of the positional relationship between a laser beam and a defective pixel;

9 is a plan view showing an outline of the positional relationship between a laser beam and a defective pixel;

10A is an enlarged top view showing the positional relationship between respective irradiation surfaces of laser light in the case of overlapping;

Fig. 10B is an enlarged top view showing the positional relationship between the irradiation planes of the laser beams at a distance,

FIG. 11A is an enlarged view of the upper surface per unit area in FIG. 10A; FIG.

FIG. 11B is an enlarged view of the upper surface per unit area in FIG. 10B; FIG.

12A is an enlarged top view of a portion subjected to laser irradiation by the method for manufacturing a liquid crystal display device of the present invention, (B) is a sectional view seen from the line X-X 'of (a),

13 is a graph showing the relationship between P / d and transmittance (T),

14 is a graph showing the relationship between P / d and irradiation energy (E).

15 is a plan view showing the relationship between a pixel electrode, a main TFT and a sub TFT in the liquid crystal display device of the present invention;

16 is a plan view illustrating a state in which wirings connecting the main TFT and the pixel electrode of FIG. 15 are cut by laser light;

FIG. 17 is a plan view showing a state in which wirings connecting the sub TFTs of FIG. 15 and pixel electrodes are connected by laser light;

18 is a cross-sectional view taken along line AA ′ of FIG. 17;

FIG. 19 is a flowchart illustrating a series of processes of FIGS. 15 to 17.

* Explanation of symbols for the main parts of the drawings

1: liquid crystal display device 2: array substrate

3: counter substrate 4: first alignment layer

5: 2nd alignment film 6: liquid crystal

7: first polarizing plate 8: second polarizing plate

9: glass substrate 10: signal line

11: scanning line 12: TFT

13: pixel electrode 14: undercoat

15: amorphous silicon film 16: channel protective film

17: n ⁺ type hydrogenated amorphous silicon film 18: source electrode

19: drain electrode 20: storage capacitor line

21: Shading layer 22: Color part

23: organic protective film 24: counter electrode

25: laser repair device 26: laser oscillator

27: processing objective lens 28: laser power source

29: Variable Attenuator 30: Shutter

31: liquid crystal panel 32: XY stage

33: mirror 34: camera

35: opening 36: light

37: controller 38: irradiation surface

39: by-product 40: main TFT

41: sub TFT 42: interlayer insulating film

43: wiring

According to claim 1 of the present invention, a step of forming at least a first electrode and a first alignment film on a first substrate, a step of forming at least a second electrode and a second alignment film on a second substrate, the first substrate and Sealing the substrates while the liquid crystal is sandwiched between the second substrates while facing each other; causing a potential difference between the first electrode and the second electrode to cause a screen to be displayed, and performing the inspection; A method of manufacturing a liquid crystal display device comprising the step of repairing a portion where a defect of a pixel constituting the screen detected by the step is generated, wherein the repairing step corresponds to the pixel having the defect. One switching element is selectively and electrically connected to the pixel with respect to a switching element in which at least two of each pixel are respectively mechanically connected. And a step of irradiating the pixel having the defect with the laser light to at least alter the first alignment film or the second alignment film.

According to claim 2 of the present invention, in the method for manufacturing a liquid crystal display device according to claim 1, the step of altering the first alignment layer or the second alignment layer includes a step of selectively and electrically connecting one switching element to the pixel. Although it was implemented, it is characterized by implementing to the pixel which the said defect is not repaired.

According to the third aspect of the present invention, in the method of manufacturing a liquid crystal display device according to claim 1 or 2, the laser beam has a pulse width of 20 ns to 200 ns in a process of selectively and electrically connecting the switching element to the pixel. In the case of the step of at least altering the first alignment film or the second alignment film, it has a pulse width of 10 ns or less.

According to claim 4 of the present invention, a step of forming at least a first electrode and a first alignment film on a first substrate, a step of forming at least a second electrode and a second alignment film on a second substrate, the first substrate and Sealing the substrates while facing each other in a state where the liquid crystal is sandwiched between the second substrates, causing a potential difference between the first electrode and the second electrode to display a screen, and performing the inspection; Irradiating a laser beam to a pixel of a portion of the portion of the pixel constituting the screen detected by inspection to denature at least the first alignment layer or the second alignment layer to repair the pixel generating the defect; In the method of manufacturing a liquid crystal display device, the repairing step is smaller than the size of the pixel with respect to the pixel that caused the defect. Irradiating a pulsed laser beam having a slope so that the plurality of the irradiation surfaces are spaced apart from each other; and by the irradiating step, the alignment film of the irradiation surface is almost extinguished, Pixels scattered by the energy having the laser light in a rippled shape around the irradiated surface, and the defects are generated more than before the irradiation of the laser light by the extinction accumulated in the rippled shape and the extinction. It is characterized by having a process of reducing the transmittance or reflectance of the light at.

According to claim 5 of the present invention, a first substrate having at least a first electrode and a first alignment layer formed thereon, a second substrate having at least a second electrode and a second alignment layer formed thereon, and sealed between the first substrate and the second substrate; At the same time, the liquid crystal is arranged in a predetermined direction based on the alignment imparted to the first alignment film and the second alignment film, and based on the orientation based on the potential difference generated in the application of the voltage between the first electrode and the second electrode. A liquid crystal display device comprising a plurality of pixels in which the transmittance or reflectance of light by the liquid crystal is changed, wherein the plurality of pixels have switching elements in which at least two pixels are provided in correspondence with the pixel, respectively. At least one of the plurality of pixels is less than the first alignment layer or the second alignment layer due to irradiation with laser light. Also it characterized by having the altered portion.

According to claim 6 of the present invention, a first substrate having at least a first electrode and a first alignment layer formed thereon, a second substrate having at least a second electrode and a second alignment layer formed thereon, and sealed between the first substrate and the second substrate; At the same time, the liquid crystals are arranged in a predetermined direction based on the orientations imparted to the first alignment layer and the second alignment layer, and based on the orientations in accordance with the potential difference generated in the application of the voltage between the first electrode and the second electrode. In a liquid crystal display device comprising a plurality of pixels in which the transmittance or reflectance of light by the liquid crystal is changed, the plurality of the irradiation surfaces are spaced apart from each other by a pulsed laser beam having an irradiation surface smaller than the size of the pixel. The portion of the at least two irradiated alignment films that have been irradiated almost disappears and the alignment films at the periphery of the irradiated surfaces. By the energy of the laser light by about the illuminated surface to stir the shape is characterized by having a non-product portion of the accumulation.

According to the seventh aspect of the present invention, a laser light source for irradiating a laser light to the alignment film constituting the liquid crystal panel, a laser light control device for adjusting the pulse width of the laser light emitted from the laser light source, and the liquid crystal panel is provided And a mounting table and scanning means for relatively scanning the laser light with respect to the liquid crystal panel, wherein the laser light control device is adapted to adjust energy input to excite the laser light source. By adjusting the pulse width.

According to claim 8 of the present invention, a laser light source for irradiating laser light to the alignment film constituting the liquid crystal panel, a laser light control device for adjusting the pulse width of the laser light emitted from the laser light source, and the liquid crystal panel is provided And a mounting table and scanning means for relatively scanning the laser light with respect to the liquid crystal panel, wherein the laser light control device is configured to open and close with a Q switch constituting the laser light source. The pulse width is adjusted by adjusting the input energy.

According to the present invention, a mechanism for repairing a defective pixel is actively used, and it is also possible to face defects caused by TFTs or wirings not being normally formed or defects caused by foreign matter between the array substrate and the opposing substrate. Accumulation of ions at the pixel electrode corresponding to the pixel can be suppressed. As a result, a liquid crystal display device having good display characteristics can be obtained.

Hereinafter, with reference to a simplified drawing of an example of the first embodiment of the present invention, an active matrix liquid crystal display device (5 inches diagonal) that is transmissive in a normally white mode will be described as an example. The present invention can also be applied to a normally black mode or a reflective liquid crystal display device.

Fig. 1 shows a cross-sectional view of a pixel portion of a liquid crystal display device according to the present embodiment, and Fig. 2 shows a top view of this pixel portion. 1 has shown the cross section in the Y-Y 'line | wire of FIG. In the liquid crystal display device 1, the array substrate 2 (example of the first substrate) and the counter substrate 3 (example of the second substrate) are each made of a polyimide first alignment film 4 and second alignment film ( 5), the spacer (not shown) is used as the support, and is sealed with a sealing agent (not shown) in a state of holding the twisted nematic liquid crystal composition (hereinafter, simply referred to as liquid crystal) 6. The liquid crystal 6 is configured such that its molecules are twisted 90 degrees between the array substrate 2 and the counter substrate 3. Further, the first polarizing plate 7 and the second polarizing plate 8 are attached to the outer surfaces of the array substrate 2 and the counter substrate 3 in a state where their polarization axes are orthogonal to each other (cross nicol state).

The liquid crystal 6 may be filled by dropping the liquid crystal onto the array substrate 2 or the counter substrate 3 before sealing with the sealing agent and then bonding the array substrate 2 and the counter substrate 3 to each other. After sealing with the sealing agent, the liquid crystal 6 may be injected or vacuum sucked into the sealing space portion of the array substrate and the counter substrate formed by the sealing and injected from the sealing agent.

In the array substrate 2, 640 × 3 signal lines (referred to as source electrode lines) 10 and 480 scan lines (referred to as gate electrode lines) 11 are arranged so as to be substantially orthogonal on the transparent glass substrate 9. . In the vicinity of the intersections of the signal lines 10 and the scanning lines 11, the pixel electrodes 13 are arranged through the TFTs 12, which are switching elements, respectively. The pixel electrode 13 is formed to have a side of 80 mu m along the signal line 10 and a side of 60 mu m along the scanning line 11. The pixel electrodes 13 are arranged side by side at a pitch of 100 μm to form the display surface of the liquid crystal display device 1.

As shown in the schematic configuration of the LCD unit in Fig. 3, the driving unit for controlling the scanning line and the signal line is composed of a gate driver and a source driver, respectively (although not shown in detail, but usually a driving driver respectively outside the display surface). Connect the module of). The video signal from the signal controller, the sync signal, and the power from the power supply unit are respectively input to each driver.

The gate driver is a digital circuit having a function of selecting each scan line once per frame (60 ms), and operates at a cycle of scanning time (15 to 40 ms). The source driver is formed on the pixel electrode 13 (example of the first electrode) and the counter substrate 3 formed of a transparent anisotropic conductive film (hereinafter, referred to as an indium tin oxide (ITO) film) formed on the array substrate 2. It operates by generating a potential difference with respect to the liquid crystal 6 filled between the counter electrodes (example of the second electrode) made of the ITO film formed in the same manner.

Specifically, by applying a voltage to the scan line, a circuit for applying a voltage corresponding to the video information through the TFT 12 is formed. At this time, if direct current power is continuously applied to the liquid crystal 6, the display is deteriorated, and thus alternating voltage is applied to the counter electrode to alternately apply a voltage of opposite polarity. This is called inversion driving, and accordingly, the source driver operates at a high frequency of 20 to 100 Hz.

By the way, the TFT 12 uses the scan line 11 itself as a gate electrode, but on the glass substrate 9, first, SiO _X , SiN _X or TEOS (Tetra Ethyl OrthoSilicate: Si [OC ₂ H ₅ ] _4). And an undercoat (insulating film) 14 composed of a thin film layer) and an amorphous silicon (a-Si: H) film (hereinafter, simply referred to as a semiconductor film) 15, which is an amorphous semiconductor film containing hydrogen, is formed in this order. It is. In addition, CVD (Chemical Vapor Deposition) is usually used here as a film forming means.

On the semiconductor film 15, a channel protective film 16 is self-aligned with the scan line 11 and formed using SiN _X. The semiconductor film 15 is electrically connected to each pixel electrode 13 through an n ⁺ type a-Si: H film and a source electrode 18 arranged as the low resistance semiconductor film 17. have. The semiconductor film 15 is also electrically connected to the signal line 10 through an n ⁺ type a-Si: H film (low resistance semiconductor film) 17 and a drain electrode 19 extending from the signal line 10. It is.

In addition, the storage capacitor line 20 is formed substantially parallel to the scan line 11 and has a region overlapping with the pixel electrode 13, and is supported by the pixel electrode 13 and the storage capacitor line 20. The capacitance Cs is formed. In addition, the storage capacitor line 20 is configured to have almost the same potential as the counter electrode 3.

On the counter substrate 3 and the transparent glass substrate 9, the gap between the TFT 12 and the signal line 10 and the pixel electrode 13 formed on the array substrate 2, or the scanning line 11 and the pixel electrode 13 In order to shield each of the space | intervals of ()), the light shielding layer 21 (BM: Brack Matrix) which consists of Cr (chrome) and CrO which laminated | stacked each other in matrix form is provided. This structure is formed through a PEP (Photo Engraving Process) process.

Moreover, in each pattern of the matrix type in the light shielding layer 21, in order to implement color display on a display surface, the color part by the color filter comprised from three primary colors of red (R), green (G), and blue (B). At the same time, the counter electrode 24 made of a transparent ITO film is provided through the organic protective film 23. The operation of the liquid crystal display device 1 in the normally white mode will be described below with reference to FIGS. 4A and 4B.

In addition, in the present specification, a twisted nematic mode will be described as an example, but since the operation principle using the alignment layer and the liquid crystal molecules is not changed, a chiral nematic liquid crystal composition or a chiral compound is added to the nematic liquid crystal composition. Consists of one Super Twisted Nematic Mode, Double Super Twisted Nematic Mode, Triple Super Twisted Nematic Mode, and FSTN Mode or Chiral Smectic Liquid Crystal Composition Ferroelectric Liquid Crystal Mode and the like, of course, are also subjects of the present invention.

Since the liquid crystal molecules constituting the liquid crystal 6 each have a polarity, they are arranged in a constant direction when an electric field is applied. The display of the screen by liquid crystal uses this property. First, as shown in FIG. 4A, the incident light is the first polarizing plate 7 until the potential difference generated between the pixel electrode 13 and the counter electrode 24 is from the threshold voltage at which the liquid crystal 6 causes alignment to 0 (V). The linear polarization is performed and the second polarizing plate 5 passes through the second polarizing plate 5 with approximately 90 degrees of polarization axis along the alignment direction of each liquid crystal molecule constituting the liquid crystal 6. As a result, the liquid crystal display device 1 Incident light is emitted to the display screen to show white (bright) pixels. This is because the first polarizing plate 7 and the second polarizing plate 8 are disposed at the cross nicol position.

In contrast, as shown in FIG. 4B, when the potential difference generated between the pixel electrode 13 and the counter electrode 24 is larger than the threshold voltage at which the liquid crystal 6 causes alignment, each liquid crystal molecule is arranged along the electric field. Therefore, the incident light is linearly polarized by the first flat plate 7 and tries to pass through the liquid crystal 6 as it is. However, the linearly polarized light passing through the liquid crystal 6 cannot pass through the second polarizing plate 8 because the second polarizing plate 8 has a polarization axis that is shifted by 90 ° from the incident light. As a result, incident light is not emitted to the display screen of the liquid crystal display device 1, and black (dark) pixels are displayed. This is because the 1st polarizing plate 7 and the 2nd polarizing plate 8 are arrange | positioned in the position of parallel nicol.

Although the above has described the normally white mode, in the case of the normally black mode, the display of the white pixels and the black pixels is replaced, but the operation itself does not change. The color of the display pixel is only changed by the mode difference above and below the threshold voltage.

Next, in the liquid crystal display device 1 of the normally white mode, conductive foreign matter is mixed between the pixel electrode 13 and the counter electrode 24 in the process of being manufactured, and thus the pixel electrode 13 and the counter electrode are mixed. Although the 24 is almost the same potential, the pixel electrode and the storage capacitor line 20 are short-circuited due to poor insulation of the insulating film 14, and the pixel electrode 13 is almost the same as the potential of the counter electrode 24. The potential difference between the pixel electrode 13 and the counter electrode 24 is almost always 0 (V) due to factors such as almost coincidence with respect to the capacitor line 20. In this case, the transmittance on the display screen of the liquid crystal display device 1 always increases to cause bright spot defects.

In this embodiment, pixels in which bright spot defects have occurred are detected as follows. First, a signal voltage V _sig whose polarity is inverted is applied to the signal line 10 of the liquid crystal display device 1 at +5 (V) and -5 (V) at each frame time centered on a predetermined voltage. In addition, a pulse-shaped scan is performed on each scan line 11 by applying a counter voltage V _com of 5 V to the counter electrode 24 and a voltage of 5 V to the storage capacitor line 20. The voltage (V _g ) is supplied in turn to give a black (dark) mark.

Then, display luminances of any one hundred display pixels located in the periphery and the center of the display screen are detected and the average value is stored as the "black level of reference". Thereafter, the display screen is sequentially scanned to detect pixels whose luminance is greater than or equal to 30% and displayed for the black level of this reference, and stores their positions. The pixel corresponding to this position is processed as a pixel in which a bright spot defect has occurred.

The method of repairing the pixel in which the bright spot defect detected in this way was detected by irradiation of a laser beam is described below. First, FIG. 5 shows a laser repair device 25 that performs this correction. As the laser oscillator 26, an Nd: YAG laser of an AO (acousto-optic: acoustic optical) -Q switch operation using a semiconductor laser (hereinafter referred to as LD) not shown in the excitation light source was used. In addition, in order to use a general purpose optical microscope objective lens as the processing objective lens 27, the laser beam from this laser oscillator 26 is a fundamental wave of a Nd: YAG laser or an Nd: YLF laser, and a second high frequency. And the third high frequency and the fourth high frequency which are ultraviolet light. LD may be replaced with a krypton arc lamp.

This laser repair device 25 is capable of changing the pulse width (inverse of "repetition frequency x 2") of the laser light so as to correspond to the repair method described at the end of the present specification. In the solid state laser of general AO-Q switch operation, when the length of the laser resonator (the distance between the pair of resonant mirrors constituting the laser oscillator 26) is constant, the excitation input (the amount of applied power to the LD) and the inside of the laser resonator are This pulse width is changed by the energy loss.

In other words, when the excitation input becomes small or the energy loss inside the laser resonator becomes large, the energy loss inside the laser resonator is increased by applying the pulse width to the AO-Q switch at the timing at which the laser light is emitted. It can be controlled by changing the size of. In the case of not controlling the power applied to the AO-Q switch, it can be controlled by changing the magnitude of the applied power to the LD. In addition, adjustment of this electric power magnitude is performed by adjustment of the supply power from the laser power supply 28. As shown in FIG.

Here, an example in the case where the magnitude | size of the applied electric power to LD is specifically changed is shown. When the applied current is changed with the repetition frequency of the laser beam being 1 or less at a constant applied voltage (usually about 2 to 3 (V)), the relationship between the applied current to the LD and the pulse width of the laser beam (in the dotted line) And the relationship between the applied current to LD and the energy of the laser light (indicated by the solid line) are as shown in FIG. In this graph, since the applied current to LD corresponds to the excitation input, it can be seen that as the applied current to LD becomes smaller, the pulse width becomes longer and the energy of the laser light becomes smaller. That is, when the length of the laser resonator is constant, it can be seen that the pulse width of the laser light changes depending on the excitation input.

However, when the pulse width is changed in this manner, the energy of the laser light is also changed, so that the laser repair device 25 is equipped with a variable attenuator (variable light attenuator) in order to repair the defective pixel with the optimal energy. It is preferable that 29 is provided. By adjusting the variable attenuator 29 and controlling the magnitude of the applied power to the LD or the magnitude of the applied power to the AO-Q switch, the repair of the defective pixel at the optimal energy is performed by one laser. This is because the oscillator is easily used.

The other laser repair device 25 includes a shutter 30 for turning on / off the laser light that has passed through the barrier attenuator 29, and a liquid crystal panel having a defective pixel. Display panel) 31 and XY stage 32 as one means for relatively scanning the laser light and the liquid crystal panel 31, the mirror 33 for guiding the laser light to the XY stage 32; The liquid crystal panel 31 through the objective objective 27 for collecting and irradiating the laser beam with the defective pixel, the camera 34 for imaging the repair situation of the defective pixel, and the opening 35 provided in the XY stage 32. There is a light 36 for illuminating). In addition, the applied power supplied from the laser power supply 28 to the LD, the applied power supplied to the AO-Q switch, opening and closing of the shutter 30, the light attenuation rate of the variable attenuator 29, and the XY table ( It has a controller 37 for controlling the operation of the 32.

Here, the repair of the defective pixel performed by this laser repair apparatus 25 will be described. In addition, the term "repair of a defective pixel" referred to herein refers to a backlight of 650 (l _x ) arranged on the back surface of the array substrate 2 when the transmittance described above is used as a reference, When the transmittance of a pixel having a severe degree of bright point defect is 100%, it is assumed that the decrease is 20% or less after the treatment with the laser light. For example, the most severe point defect is a case where the pixel electrode 13 and the storage capacitor line 20 are short-circuited and the potential difference between the pixel electrode 13 and the counter electrode 24 becomes almost 0 (V). In this case, even when a voltage difference higher than the above-described threshold voltage with respect to the liquid crystal 6 is applied between the pixel electrode 13 and the counter electrode 24, it has a transmittance of almost 100% similar to that of a normal pixel.

By the way, as shown in FIG. 7, it is preferable to irradiate a laser beam so that it may inject from the 2nd alignment film 5 here, and may connect a light converging point in the liquid crystal 6. The light converging point is not disposed on the array substrate 2 or the counter substrate 3 so as to be strong against the pixel electrode 13 or the counter electrode 24 itself or the first alignment film 4 or the second alignment film 5. This is to prevent energy from entering and causing harm. Further, of course, the laser beam may be incident from the first alignment film 4 in the same manner.

The laser light emitted from the laser oscillator 26 (Nd: YAG) is irradiated with a wavelength of 1.06 (占 퐉) and a diameter of the laser spot on the defective pixel (diameter of the irradiation surface of the laser light) of 2.5 (占 퐉). At this time, the repetition frequency is 100 (kHz), the scanning speed at the defective pixel is 1 (mm / s), and the output of the laser light to be irradiated is 2 (μJ / pulse). The outline of the positional relationship between the laser beam and the defective pixel in this scanning is made as shown in Fig. 8, and the laser beam scans the inside of the defective pixel while repeating the image in the vertical direction.

More specifically, as shown in FIG. 9. From one end (for example, point a in the figure) of the pixel electrode 13 that is causing defects along the longitudinal direction of the scanning line 11, the other end (for example, point b in the figure) is connected to the pixel electrode ( Scanning is performed in parallel with the short side of 13), and the scanning direction is repeatedly repeated at the other end toward the upper side in the drawing (for example, to point c in the drawing). Here, it is preferable that the said one end part (a point) which is the start point of a scanning has the distance L from the edge part of the opening part (light transmission part) defined by the light shielding layer 21 at least 7 micrometers apart. This is because if the distance L is too small, the fly-bye generated by the laser light described later scatters even to the pixel electrode 13 displaying the normal display, causing a new display defect.

Here, the characteristic in the irradiation of the laser beam shown to FIG. 10A and FIG. 10B to the enlarged view of FIG. 9 is demonstrated. FIG. 10A is a method of scanning while overlapping a laser irradiation surface that has been previously performed, and FIG. 10B is a method of scanning discretely the laser irradiation surface. In addition, in FIG.9 and FIG.10B, "d" has shown the diameter of the irradiation surface of a laser beam, and "P" has shown the distance (pitch) between the centers of each irradiation surface. This pitch can be changed by changing the scanning speed or repetition frequency.

Here, the input energy will be considered under the precondition that the diameter of the irradiation surface of the laser beam is the same in the scanning method having the overlap ratio performed in FIG. 10A and the discrete scanning method performed in FIG. 10B. 11A shows the irradiated surface per unit area when there is 50% overlap, and FIG. 11B shows the irradiated surface per unit area in the same manner as in the discrete case at P / d = 2. In both drawings, the unit area where the irradiation surface is formed is a part surrounded by a broken line.

In the case of Fig. 11A, since the number of irradiation of the laser light is large, a processing time of about 30 seconds was taken per pixel. And the output of the laser beam to irradiate was 0.5 (microJ / pulse). On the other hand, in the case of Fig. 11B, since the number of irradiation of the laser light is small, it is possible to have a processing time of about 3 seconds per pixel. And the output of the laser beam to irradiate was 2 (microJ / pulse). Comparing the data for these two methods, it can be seen that the product of the irradiation time and the energy per pulse is significantly different.

That is, in the case of FIG. 11A, when the total irradiation surfaces are combined, eight irradiations are received per unit area, and the irradiation energy per unit area is 0.5 × 8 = 4 (μJ / pulse). On the contrary, in the case of FIG. 11B, four investigations are performed, but since there is a discrete state of P / d = 2, only the diagonal line has investigation. Therefore, the irradiation energy per unit area becomes 2 × 4 × 0.25 = 2 (μJ / pulse) since the irradiation is carried out 0.25 times per unit area. That is, the total amount of irradiation energy per unit area is 1/2 of the case of FIG. 11A.

As a result, even if the irradiation energy per pulse is large, it can be seen that the total amount of irradiation energy is small in the method of discrete irradiation as shown in Fig. 11B. The short irradiation time and the small amount of irradiation energy are effective considering the solution of the array substrate 2 or the counter substrate 3. In addition, since the energy per one irradiation is large and the number of irradiation times is small, a margin of processing of about 10% can be obtained.

On the contrary, in the method of overlapping irradiation as shown in Fig. 11A, since the irradiation energy per one is small and the number of irradiation is large, the machining margin is inevitably narrowed by ± 5%. When overlapping, the irradiation energy per unit area increases, and even if the energy is slightly increased due to the output variation of the laser oscillator 26, structures such as the color portion 22 are damaged by thermal energy and cause new defects.

In this overlapping method, the liquid crystal 6 may be heated by the irradiation energy to vaporize the liquid crystal 6 to generate a large number of bubbles. In addition, irregularly generated bubbles change the position and size of the irradiation surface of the laser light, and on the surface of the array substrate 2 or the counter substrate 3 from which the liquid crystal 6 is removed by the bubbles, the laser light is directly irradiated. The solution gives rise to thermal energy, which causes new defects.

Although the first alignment film 4 and the second alignment film 5 are obtained by rubbing a polyimide film having a thickness of several tens (nm), the variation of the thickness in the manufacturing process does not affect the display quality of the image. It is managed in the range of accuracy (± 10%). In the repair of defective pixels, due to the deviation (i.e. disturbance) of the film thickness of ± 10%, a good repair site and a poor repair site occur, and a sufficient transmittance can be achieved even if treated under the same conditions (repair) In case of insufficient reproducibility).

When the processing margin is large with respect to the energy of laser irradiation to such an extent that this disturbance can be tolerated, the reproducibility of a restoration can fully be obtained even if it processes on the same conditions. As described above, according to the discretely irradiated method of the present invention, the machining margin can be set to ± 10%, and the machining margin can be larger than the overlapped irradiated method.

In practice, the proper repair conditions for 50% overlap rate include a laser spot diameter of 2.5 μm, a scanning speed of 1 mm / s, a repetition frequency of 1 μm, and an irradiation energy of 0.50 to 0.55 μJ /. pulse), but the machining margin was low (± 5%), so the probability of successful repair of a defective pixel was only 70%.

On the other hand, suitable repair conditions in the case of P / d = 2 include a laser spot diameter of 2.5 (µm), a scanning speed of 1 (mm / s), a repetition frequency of 100 (Hz), and an irradiation energy of 1.0 to 2.0 (µJ). / pulse) and a high machining margin of ± 10%, the probability of success in repairing defective pixels is 100%.

Next, the reason why the defective pixel is repaired in this discrete and laser irradiation method will be described with reference to FIG. FIG. 12A is an enlarged plan view of a portion subjected to laser irradiation, and FIG. 12B is a sectional view seen from the line X-X 'of FIG. As can be seen from FIG. 12 (a), "opacity" is generated in a rippled shape around the irradiation surface 38 of the laser light. This "opacity" does not show any suggestion in the first conventional example, and it is a feature of the present invention to perform repair of a defective pixel using this opacity (mechanism not disclosed in the first conventional example). will be.

As can be seen in FIG. 12B, the first alignment film 4 is cut out by the irradiation energy from the irradiation surface 38 of the laser beam to reach the pixel electrode 13 composed of the ITO film, in particular, the array. When the laser beam is incident from the substrate 2 side, the peripheral color portion 22 is also reached to form a portion where the first alignment layer 4 almost disappears. And the fly-product 39 which consists of polyimide ITO, the fine solidified substance of dye, the solidified substance of the deteriorated liquid crystal, etc. is shown in FIG. 12 around the periphery (position corresponding to "opacity") of the irradiation surface 38 of a laser beam. A fine rubbing groove (not shown) formed on the surface of the first alignment film 4 is filled in a rippled shape around the irradiated surface 38 of the laser beam as shown in (a). Therefore, since the homology of the liquid crystal 6 changes, it is thought that this opacity occurs because the first alignment film 4 forms a deteriorated portion when viewed in a macroscopic manner.

As a result, the rubbing grooves are filled by the scatterings 39, so that each liquid crystal molecule constituting the liquid crystal 6 is arranged along the electric field generated at the voltage applied between the pixel electrode 13 and the counter electrode 24. It becomes impossible. And since the liquid crystal 6 cannot orientate (because orientation is falling), the passage and reflection of the light through the liquid crystal 6 are disturbed, and it becomes a defective pixel.

That is, in the overlapping method as shown in Fig. 10A, in addition to cutting all the alignment film, the ITO film, and the color portion from the scanning surface, the above-mentioned "opacity" was not formed because the irradiation energy per pulse was small. However, according to this method, only the irradiation surface 38 of the laser beam can be shaved even up to that point, and the other regions are scattered by the scattering 39, whereby the alignment of the liquid crystal molecules is inhibited. ), The solution is less in the entire liquid crystal panel 31.

In this overlapping method, an increase in transmittance was confirmed when operating in a dry environment at 85 ° C. In contrast, in this method, there was little variation in transmittance. It is considered that this method is because rubbing grooves are filled in the fly-by-product 39, and resurrection of orientation is unlikely to occur even after the temperature raised by laser irradiation falls.

FIG. 13 shows the relationship between P / d and transmittance T, and FIG. 14 shows the relationship between P / d and irradiation energy E. FIG. In consideration of the margins, the values are changed in the area surrounded by the diagonal lines. However, according to FIG. 13, it can be seen that the transmittance reaches the minimum when P / d is 2 to 3, and in FIG. 14, the P / d is 2-3. It can be seen that when the irradiation energy can be maximized. As a result, it can be seen that when the P / d is 2 to 3, repair of the defective pixel can be realized under optimum conditions.

The method of repairing a defective pixel using the "opacity" formed on the display surface by irradiating the laser light as described above can be applied to a display device having an alignment film in principle. The object is not limited to the active matrix liquid crystal display device using TFT as the switching element mentioned in the description. For example, MIM (Metal Inslator Metal) may be used, or a simple matrix liquid crystal display device using no switching element may be used. Also, a plasma address liquid crystal (PALC) may be used.

In addition, although the pixel with a bright point defect was demonstrated as an example, this method is effective also about another defect mode. For example, abnormal operation of a switching element due to electrostatic breakdown, short circuit of an electrode or wiring due to breakage of an interlayer insulating film, and defect or orientation abnormality of a pixel electrode.

Next, a method of performing another repair in addition to the method of repairing a defective pixel by irradiating the laser light discretely described so far will be described below. This method can also be referred to as a method combining both the first conventional example and the second conventional example, but the idea of compensating for the omission of the defect pixel correction in each of the conventional examples is not disclosed. In addition, it is preferable to perform this method using the laser repair apparatus 25 with a variable pulse width shown in FIG.

As shown in Figs. 15 to 18, in the method described here, two TFTs (switching elements) are provided respectively corresponding to one pixel electrode 13 in the same manner as in the second conventional example. As shown in Fig. 15, one side is the main TFT 40 which is mechanically and electrically connected to the pixel electrode 13 by wiring, and the other side is not mechanically connected to the pixel electrode 13 but electrically connected thereto. The sub TFT 42 (which is in mechanical contact with the wiring 43 extending from the scanning line 11 insulated by the interlayer insulating film 41). First, the pixel which a defect generate | occur | produces through detection of the pixel defect mentioned above.

Next, if a portion where pixel defects occur can be identified, as shown in FIG. 16, first, the wiring connecting the main TFT 40 and the scanning line 11 to the defective pixels caused by the malfunction of the main TFT 40 is performed. The 43 is cut by the laser beam used in the laser repair apparatus 25. The pulse width of the laser light at this time is set short to 10 (ns) or less in order to melt cut the wiring, and is cut by irradiating the pulsed laser light.

Next, as shown in FIG. 17, the sub-TFT 42 connected to the pixel electrode 13 is selected, and the pixel electrode 13 electrically cut out from the main TFT 40 by the interlayer insulating film 41; The sub TFT 42 is irradiated with laser light from the laser repair device 25 to be selectively and electrically connected. Specifically, the pixel electrode 13 and the electrode of the sub TFT 42 are fusion-connected with a laser beam through the interlayer insulating film 41 as shown in FIG. 18 as a cross sectional view along the line A-A 'of FIG. For this reason, the pulse width of the laser light is set to 10 (ns) or shorter here, and both of them are irradiated with the pulsed laser light.

The pixel performs normal operation for repairing pixel defects by this process, but it is not possible to repair pixel defects that are not caused by TFT malfunction, and there is a variation in processing accuracy due to laser light. Only about 30 to 50% of the total defects can be repaired.

Therefore, after the replacement and attachment to the sub-TFT 42 is performed, the pixel defect is checked again. If the pixel defect is recognized, for example, the method shown in the first conventional example in the method of irradiating laser light discretely as described above is shown. As described above, the repair of the defective pixel using the disturbance of the alignment film is also performed. This series of steps is shown in a flowchart in FIG. 19 (the change of the connection to the sub TFT 42 is a kind of the change of the connection to the saving circuit).

In this process, the pulse width of the laser beam used in the laser repair apparatus 25 is set to 20 to 200 ns. Of course, instead of the first conventional example, the laser light described above may be irradiated discretely to form "opacity" to repair the defective pixel.

In addition, although the active matrix type liquid crystal display device using TFT was demonstrated as an example as a switching element, you may make it the MIM type liquid crystal display device instead.

According to the present invention, it is possible to achieve correction of a defective pixel which suppresses thermal damage to the liquid crystal panel. Further, the defective pixel can be corrected appropriately in response to various defect modes including a malfunction of the switching element. That is, according to the present invention, it becomes possible to manufacture a liquid crystal display device in which good repair of defective pixels is achieved. In addition, it is also possible to provide a laser repair apparatus for such repair.

Claims (10)

In the manufacturing method of the liquid crystal display device, Forming at least a first electrode and a first alignment layer on the first substrate, Forming at least a second electrode and a second alignment layer on the second substrate; Sealing the substrates while facing each other in a state where liquid crystal is interposed between the first substrate and the second substrate; Detecting a pixel in which a defect occurs because a screen is displayed by causing a potential difference between the first electrode and the second electrode; Irradiating a pulse laser beam to the wiring connecting the switching element and the scanning line corresponding to the defective pixel, and cutting the wiring; Re-inspecting the pixel in which the defect occurred after cutting the wiring; If the pixel defect is still recognized by the re-inspection, a plurality of pulse-shaped laser beams having an irradiation surface smaller than the size of the pixel having the defect are applied to any one of the first alignment film and the second alignment film. Irradiating each other at a distance from each other so as to reduce the transmittance of light in the pixel where the defect is generated than before the laser light is irradiated. Method of manufacturing a liquid crystal display device comprising a. delete delete Forming at least a first electrode and a first alignment layer on the first substrate, forming at least a second electrode and a second alignment layer on the second substrate, and a liquid crystal between the first substrate and the second substrate Sealing the substrates while facing each other with the interposed therebetween; causing a potential difference between the first electrode and the second electrode to cause a screen to be displayed, and performing the inspection; By irradiating a laser beam to a pixel of a portion where a defect of a pixel constituting the screen is generated, at least one of the first alignment film and the second alignment film is deteriorated to repair the pixel that has generated the defect. In the manufacturing method of the liquid crystal display device provided with the process of The repairing step includes a plurality of the irradiation surfaces of the laser-shaped laser light having an irradiation surface smaller than the size of the pixel with respect to any one of the first alignment film and the second alignment film of the pixel that caused the defect. A step of investigating the separation from each other, By the irradiation step, the alignment film of the irradiation surface is extinguished, and scattered products are accumulated by the energy of the laser light in a rippled shape around the irradiation surface with respect to the alignment film on the periphery of the irradiation surface. A step of reducing the transmittance of light in the pixel which caused the defect than before the laser light is irradiated by the scattered product accumulated in the ripple shape and the extinction. Method for manufacturing a liquid crystal display device characterized in that it comprises. delete A first substrate having at least a first electrode and a first alignment film formed thereon, a second substrate having at least a second electrode and a second alignment film formed thereon, and being sealed between the first substrate and the second substrate, the first alignment film and the Transmittance and reflectance of the light by the liquid crystal based on the orientation according to the liquid crystal arranged in a predetermined direction based on the orientation imparted to the second alignment film and the potential difference generated in the application of the voltage between the first electrode and the second electrode. A liquid crystal display device comprising: a plurality of pixels at which any one of them is changed; At least one of the alignment layers of the first alignment layer and the second alignment layer is irradiated with a pulsed laser beam having an irradiation surface smaller than the size of the pixel such that the plurality of the irradiation surfaces are spaced apart from each other so that at least two of the irradiation surfaces The portion where the alignment film has disappeared, With respect to the alignment film on the periphery of the irradiated surface, the portion of the scattered product accumulated by the energy of the laser light in a rippled shape around the irradiated surface. A liquid crystal display device, characterized in that provided. delete delete In the manufacturing method of the liquid crystal display device, Forming at least a first electrode and a first alignment layer on the first substrate, Forming at least a second electrode and a second alignment layer on the second substrate; Sealing the substrates while facing each other in a state where liquid crystal is interposed between the first substrate and the second substrate; Detecting a pixel in which a defect occurs because a screen is displayed by causing a potential difference between the first electrode and the second electrode; Irradiating a pulse laser beam to the wiring connecting the switching element and the scanning line corresponding to the defective pixel, and cutting the wiring; Re-inspecting the pixel in which the defect occurred after cutting the wiring; If the pixel defect is still recognized by the re-inspection, a plurality of pulse-shaped laser beams having an irradiation surface smaller than the size of the pixel having the defect are applied to any one of the first alignment film and the second alignment film. Irradiating each other at a distance from each other so as to reduce the reflectance of light in the pixel in which the defect is generated, rather than before the laser light is irradiated. Method of manufacturing a liquid crystal display device comprising a. Forming at least a first electrode and a first alignment layer on the first substrate, forming at least a second electrode and a second alignment layer on the second substrate, and a liquid crystal between the first substrate and the second substrate Sealing the substrates while facing each other with the interposed therebetween; causing a potential difference between the first electrode and the second electrode to cause a screen to be displayed, and performing the inspection; By irradiating a laser beam to a pixel of a portion where a defect of a pixel constituting the screen is generated, at least one of the first alignment film and the second alignment film is deteriorated to repair the pixel that has generated the defect. In the manufacturing method of the liquid crystal display device provided with the process of The repairing step includes a plurality of the irradiation surfaces of the laser-shaped laser light having an irradiation surface smaller than the size of the pixel with respect to any one of the first alignment film and the second alignment film of the pixel that caused the defect. A step of investigating the separation from each other, By the irradiation step, the alignment film of the irradiation surface is extinguished, and scattered products are accumulated by the energy of the laser light in a rippled shape around the irradiation surface with respect to the alignment film on the periphery of the irradiation surface. Reducing the reflectance of light in the pixel which caused the defect than before irradiating the laser light by the scattering and the extinction accumulated in the ripple shape Method for manufacturing a liquid crystal display device characterized in that it comprises.