JPH11167124A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device which has a larger aperture rate than a conventional display device without changing technology needed for defect repair. SOLUTION: This display devise is constituted including a 1st transparent substrate, an active matrix substrate including gate lines 1, source lines 2, and switching elements, an opposite substrate which faces the active matrix substrate, and a liquid crystal layer sandwiched between the active matrix substrate and opposite substrate, and the source lines 2 include an area to be irradiated with laser beam and removed for defect repair and an area to be left for signal transmission. In this case, the area to be removed and the area to be left are formed in one body and also selected according to be kind of a defect to be repaired.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a liquid crystal display device to which laser repair is applied for repairing defects.

[0002]

2. Description of the Related Art A liquid crystal display device comprises a liquid crystal display panel, two polarizing plates for teaching the liquid crystal display panel, a backlight for emitting light to the liquid crystal display panel, and an electric signal for driving the liquid crystal display panel. And a driving circuit for supplying

[0003] The liquid crystal display panel includes an active matrix substrate, a counter substrate, and a liquid crystal layer sandwiched between the active matrix substrate and the counter substrate.

The active matrix substrate includes a first transparent substrate, a plurality of gate lines provided on the surface of the first transparent substrate, a plurality of source lines intersecting the gate lines via an insulating film, A switching element electrically connected to one gate line and one source line; a pixel electrode provided in each pixel electrically connected to the switching element; and a storage capacitor formed between the pixel electrode and the pixel electrode. And a plurality of Cs lines to which a common signal is input. The Cs line is provided in parallel with the gate line and crosses the source line via an insulating film.

As the switching element, for example, a thin film transistor (hereinafter, referred to as “TFT”) is used. A TFT includes a gate electrode, an insulating film, a semiconductor layer, a source electrode, and a drain electrode. When a gate signal having a predetermined voltage is input to the gate electrode, the TFT changes from the off state to the on state. In the on state, a source signal input to the source electrode is applied to the drain electrode through the semiconductor layer. Usually, a portion of the gate line that contacts the semiconductor layer functions as a gate electrode, and a portion of the source line that contacts the semiconductor layer functions as a source electrode.

[0006] The counter substrate includes a second transparent substrate, a color filter provided on the surface of the second transparent substrate, and a counter electrode. An electric field is generated between the pixel electrode and the counter electrode according to a potential difference between the counter electrode and the pixel electrode. The electric field changes the arrangement of liquid crystal molecules in the liquid crystal layer, and changes the state of light deflection. By the combination of this change and the polarizing plate, the light transmittance of each pixel changes, and a desired display is realized.

Since the liquid crystal display has a large screen and a fine structure, it is difficult to produce a product having no defect. One example of the defect is that the gate line and the source line are short-circuited at the intersection of the gate line and the source line. Therefore, a technique of repairing a defect using a laser is often applied. In order to repair a defect by using a laser, it is necessary to provide a space for irradiating a laser in a source line from a design stage of a liquid crystal display device. There are the following three types of areas relating to the space for laser irradiation. Area A: Area irradiated with laser and removed Area B: Area for preventing laser damage from affecting adjacent components when irradiated with laser Area C: After laser irradiation, Area left for signal transmission

FIG. 4 is an explanatory view showing an example of an active matrix substrate of a conventional liquid crystal display device. In FIG.
One TFT of the active matrix substrate and its peripheral portion are shown. In FIG. 4, 1 is a gate line, 2 is a source line, 4 is a Cs line, 5 is a drain electrode, 10 is a pixel electrode, 11 is a semiconductor layer, 13 is a source electrode, and 16 is laser irradiated for defect repair. A first area to be removed, 17 is a second area which is irradiated with laser for defect repair and is removed, 18 is a third area which is irradiated with laser for defect repair and is removed, and 19 is defect repair. 4 shows a fourth region that is irradiated and removed for laser light. The first transparent substrate is not shown.

Which of the first region 16, the second region 17, the third region 18, and the fourth region 19 is irradiated with the laser depends on the manner of occurrence of the defect. For example, when the gate line 1 and the source line 2 are short-circuited at the intersection of the gate line 1 and the source line 2, the gate line 1 is sandwiched between the gate lines 1 and 2 in order to eliminate the mixing of the gate signal and the source signal. First area 1
6 and the second area 17 are irradiated with a laser.

FIG. 5 is an explanatory diagram showing a state where the first and second regions of the active matrix substrate of FIG. 4 are irradiated with a laser. 5, the same parts as those in FIG. 4 are denoted by the same reference numerals. Further, 6 is a portion where the first region of the source line 2 is irradiated with the laser and removed (hereinafter, referred to as a “first removed portion”), and 7 is a portion where the laser is irradiated on the second region of the source line 2. A portion that has been irradiated and removed (hereinafter, referred to as a “second removed portion”) is shown.

At this time, since the source signal is supplied to the pixel electrode 10 from below in FIG. 5 via the source line 2 and the source electrode 13, the pixel including the pixel electrode 10 does not become a defective pixel.

Further, as another example, there is a case where the Cs line 4 and the source line 2 are short-circuited at the intersection of the Cs line 4 and the source line 2. In this case, in order to eliminate the mixing of the common signal and the source signal, the third region 18 and the fourth region 19 are irradiated with the laser with the Cs line 4 interposed therebetween.

FIG. 6 is an explanatory view showing a state in which the third and fourth regions of the active matrix substrate of FIG. 4 are irradiated with a laser. 6, the same parts as those in FIG. 4 are denoted by the same reference numerals. Further, 8 is a portion of the source line 2 where the third region is irradiated with the laser and removed (hereinafter, referred to as a “third removed portion”). 9 is a region where the laser is irradiated to the fourth region of the source line 2. A portion removed by irradiation (hereinafter, referred to as a “fourth removed portion”) is shown.

At this time, since the source signal is supplied from above in FIG. 6 to the pixel electrode 10 via the source line 2 and the source electrode 13, the pixel including the pixel electrode 10 does not become a defective pixel.

Referring to FIG. 7, a description will be given of a space for repairing a defect in the prior art provided for realizing the removal as shown in FIGS.

FIG. 7 is an explanatory view showing a space for repairing a defect in the prior art. 7, the same parts as those in FIG. 5 are denoted by the same reference numerals. Further, α is the minimum slit width that can be removed by the laser, and β is a scratch on the adjacent component (in FIG. 7, the gate line 1 and the Cs line 4) due to damage to the adjacent component. A space γ provided so as not to cause a line width indicates a line width necessary for supplying a source signal to the source electrode 13. As can be seen from FIG. 7, the width of the space required for defect repair is β + α + γ + α + β = 2α +
2β + γ.

[0017]

As described above, in order to repair a defect, it is necessary to provide a space for repairing the defect from the design stage. However, if a space for repairing a defect is provided, the aperture ratio becomes low. When the aperture ratio decreases, problems such as a decrease in the brightness of the liquid crystal display device occur. Therefore, it is desirable that the aperture ratio be as large as possible.

An object of the present invention is to solve such a problem and to provide a liquid crystal display device having an aperture ratio higher than that of a conventional liquid crystal display device without changing the technique required for defect repair.

[0019]

According to the present invention, there is provided a liquid crystal display device comprising: a first transparent substrate; a plurality of gate lines provided on the surface of the first transparent substrate; An active matrix substrate including a plurality of source lines, a switching element electrically connected to one gate line and one source line, and a pixel electrode electrically connected to the switching element; A transparent substrate, comprising a counter substrate facing the active matrix substrate, and a liquid crystal layer sandwiched between the active matrix substrate and the counter substrate, wherein the plurality of source lines are used for defect repair. A liquid crystal display device including a region irradiated with a laser for removal and a region left for signal transmission. Pass is formed integrally with a region that is left above, according to the type of defect to be repaired, a region that is left above said removed the area is intended to be selected.

Further, a gate signal for turning the switching element on or off is input to the gate line.

Further, a source signal applied to a pixel electrode via a switching element in an ON state is input to the source line.

Further, the active matrix substrate may include:
And a Cs line provided in parallel with the gate line.

Further, a common signal for forming an auxiliary capacitance is input to the Cs line.

The gate line may be made of one of chromium, aluminum, tantalum, molybdenum and indium oxide, or chromium, aluminum,
It is a combination of at least two of tantalum, molybdenum and indium oxide.

The source line may be made of one of chromium, aluminum, tantalum, molybdenum and indium oxide, or chromium, aluminum,
It is a combination of at least two of tantalum, molybdenum and indium oxide.

Further, the material of the Cs line is one of chromium, aluminum, tantalum, molybdenum and indium oxide, or chromium, aluminum,
It is a combination of at least two of tantalum, molybdenum and indium oxide.

A YAG laser, wherein the laser uses one of a fundamental wave, a second harmonic and a third harmonic;
A YAG laser using a mixture of at least two of a fundamental wave, a second harmonic and a third harmonic, or Ar ₂ ,
An excimer laser using one of Kr ₂ , Xe ₂ , ArF, KrF and XeCl.

[0028]

Next, an embodiment of a liquid crystal display device of the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory view showing an example of an active matrix substrate in one embodiment of the liquid crystal display device of the present invention. FIG. 1 shows one TFT of the active matrix substrate and its peripheral portion. FIG.
7, the same parts as those in FIG. 7 are indicated by the same reference numerals.
Further, 3 indicates a source electrode.

In the liquid crystal display device of the present invention, a region irradiated with a laser for repairing a defect and removed is integrally formed with a region left for signal transmission. That is, as shown in FIG. 1, the source line 2 is formed such that the width of the source electrode extraction portion becomes α + γ.

The method for repairing defects in the liquid crystal display device of the present invention is as follows. First, a method of repairing a defect when the gate line 1 and the source line 2 are short-circuited at the intersection of the gate line 1 and the source line 2 will be described. In this case, two portions of the source line 2 separated by β from the gate line 1 are removed by a width α with a laser so as to sandwich the gate line 1.

FIG. 2 is an explanatory diagram showing an example of a state in which the active matrix substrate of FIG. 1 has been repaired for defects.
2, the same parts as those in FIGS. 1 and 5 are denoted by the same reference numerals.

Even if the second removing portion 7 is provided, a width γ (see FIG. 1) is provided below the second removing portion 7 (on the paper surface).
Are left. Therefore, the source signal is supplied to the pixel electrode 10 through the source line 2 and the source electrode 3 from below in FIG.
Pixels containing 0 do not become defective pixels.

Next, as another example, a method of repairing a defect when the Cs line 4 and the source line 2 are short-circuited at the intersection of the Cs line 4 and the source line 2 will be described. In this case, two portions of the source line 2 separated by β from the Cs line 4 are removed by the laser by the width α so as to sandwich the Cs line 4.

FIG. 3 is an explanatory view showing another example of a state where the defect repair of the active matrix substrate of FIG. 1 has been performed. 3, the same parts as those in FIGS. 1 and 6 are denoted by the same reference numerals.

Even if the third removing portion 8 is provided, a width γ (see FIG. 1) is provided above the third removing portion 8 (on the paper surface).
Are left. Therefore, the source signal is supplied to the pixel electrode 10 from above in FIG. 1 via the source line 2 and the source electrode 3, so that the pixel electrode 1
Pixels containing 0 do not become defective pixels.

As described above, the liquid crystal display device of the present invention
The defect can be repaired by using the conventional technology without changing the technology required for the defect repair. As is clear from FIG. 1, the width of the defect repair space in the liquid crystal display device of the present invention is β + α + γ + β = α + 2β + γ.
Therefore, it can be smaller by α than the conventional liquid crystal display device.

In the liquid crystal display device of the present invention, the material of the gate line is chromium, aluminum, tantalum,
It is preferable to use one of molybdenum and indium oxide or a combination of at least two of chromium, aluminum, tantalum, molybdenum, and indium oxide because the conductivity of the gate line is improved. Further, the material of the source line is chromium,
It is preferable to use one of aluminum, tantalum, molybdenum, and indium oxide, or a combination of at least two of chromium, aluminum, tantalum, molybdenum, and indium oxide, because the conductivity of the source line is improved. Further, the Cs
The line material may be one of chromium, aluminum, tantalum, molybdenum and indium oxide, or a combination of at least two of chromium, aluminum, tantalum, molybdenum and indium oxide, according to the Cs line. It is preferable because conductivity is improved.

Further, in the liquid crystal display device of the present invention, the laser includes a fundamental wave (wavelength 1.06 μm), a second harmonic (wavelength 532 nm), and a third harmonic (wavelength 355 nm).
m), a fundamental wave (wavelength 1.06 μm), a second harmonic wave (wavelength 532n)
m) and a YAG laser using a mixture of at least two of the third harmonic (wavelength: 355 nm), or Ar
₂ (wavelength 126 nm), Kr ₂ (wavelength 146 nm), Xe
₂ (wavelength 172 nm), ArF (wavelength 192 nm), K
rF (wavelength 248 nm) and XeCl (wavelength 308 n)
m) is preferably an excimer laser using one of them.

[0040]

According to the present invention, the width of the defect repair space is α + 2β + γ, which is smaller than the conventional 2α + 2β + γ. Therefore, the aperture ratio can be made higher than that of the conventional liquid crystal display device, so that the performance of the liquid crystal display device can be improved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating an example of an active matrix substrate in one embodiment of a liquid crystal display device of the present invention.

FIG. 2 is an explanatory diagram showing an example of a state where a defect has been repaired in the active matrix substrate of FIG. 1;

FIG. 3 is an explanatory diagram showing another example of a state in which the active matrix substrate of FIG. 1 has been repaired for defects.

FIG. 4 is an explanatory diagram illustrating an example of an active matrix substrate of a conventional liquid crystal display device.

FIG. 5 is an explanatory diagram showing a state in which a first region and a second region of the active matrix substrate of FIG. 4 are irradiated with a laser.

FIG. 6 is an explanatory diagram showing a state in which a third region and a fourth region of the active matrix substrate of FIG. 4 are irradiated with a laser.

FIG. 7 is an explanatory diagram showing a space for repairing a defect in the conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gate line 2 Source line 3 Source electrode 4 Cs line 5 Drain electrode 6 1st removal part 7 2nd removal part 8 3rd removal part 9 4th removal part 10 Pixel electrode 11 Semiconductor layer

Claims (9)

[Claims] 1. A first transparent substrate, a plurality of gate lines provided on a surface of the first transparent substrate, a plurality of source lines intersecting the gate lines via an insulating film, one gate line, An active matrix substrate including a switching element electrically connected to one source line, and a pixel electrode electrically connected to the switching element; and a second transparent substrate, wherein the active matrix substrate And a liquid crystal layer sandwiched between the active matrix substrate and the counter substrate, wherein the plurality of source lines are irradiated with a laser beam for repairing a defect, and a region and a signal are removed. A liquid crystal display device comprising a region left for transmission, wherein said region to be removed is integrally formed with said remaining region, and A liquid crystal display device in which the area to be removed and the area to be left are selected according to the type of defect to be restored. 2. The liquid crystal display device according to claim 1, wherein a gate signal for turning a switching element on or off is input to the gate line. 3. The liquid crystal display device according to claim 1, wherein a source signal applied to a pixel electrode via a switching element in an on state is input to the source line. 4. The liquid crystal display device according to claim 1, wherein the active matrix substrate further includes a Cs line provided in parallel with the gate line. 5. The liquid crystal display device according to claim 4, wherein a common signal for forming an auxiliary capacitance is input to said Cs line. 6. The gate line material is one of chromium, aluminum, tantalum, molybdenum and indium oxide, or a combination of at least two of chromium, aluminum, tantalum, molybdenum and indium oxide. The liquid crystal display device according to claim 1. 7. The source line material is one of chromium, aluminum, tantalum, molybdenum and indium oxide, or a combination of at least two of chromium, aluminum, tantalum, molybdenum and indium oxide. The liquid crystal display device according to claim 1. 8. The Cs line material is one of chromium, aluminum, tantalum, molybdenum and indium oxide, or a combination of at least two of chromium, aluminum, tantalum, molybdenum and indium oxide. The liquid crystal display device according to claim 4. 9. The laser of claim 1, wherein the laser is a YAG laser using one of a fundamental wave, a second harmonic and a third harmonic, and at least two of a fundamental wave, a second harmonic and a third harmonic.
YAG laser using a mixture of two, or Ar ₂ , K
one of r ₂ , Xe ₂ , ArF, KrF and XeCl
2. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is an excimer laser using one.