JP2002303881A - Electrode substrate, display panel, and repairing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform repair work with efficiency and also improve a yield by increasing a rate of success in repair using laser light to a luminescent spot pixel of a liquid crystal panel. SOLUTION: In the liquid crystal panel 100 having display pixels 10 connected with signal lines 11 and scanning lines 12 through TFTs 13 and arranged in a matrix form, a redundant circuit 20 consisting of a pair of redundant wiring 21 and 22 laminated through an insulating layer 23 is connected with auxiliary capacitance 17 in parallel, and the display pixel is made a dark spot by emitting a beam of laser to this redundant circuit 20 to short-circuit a pair of the redundant wiring 21 and 22 so that a DC voltage supplied from an auxiliary capacitance line 18 is permanently supplied to a pixel electrode 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode substrate, a display panel, and a method of repairing the same, and more particularly, to a technique of repairing a defective bright spot generated in a normally white liquid crystal panel.

[0002]

2. Description of the Related Art In recent years, flat display panels typified by liquid crystal panels have been used in various fields by making use of their characteristics such as light weight, thinness, and low power consumption. Widely used as a display.

FIG. 6 is a schematic sectional view showing the structure of a general liquid crystal panel. The structure of the liquid crystal panel 1 will be briefly described.
a and the opposite substrate 3 on which a not-shown full-surface electrode and a PI alignment film 7b are also formed on the main surface.
Are arranged opposite to each other, a sealant 4 is applied to the periphery of both substrates and bonded together, a liquid crystal 5 is sealed therein, and polarizing plates 6a and 6b are bonded to the outside of both substrates, respectively. Has become. Although not shown, a backlight serving as a light source is arranged on the back surface of the array substrate 2, and display is performed by transmitting or blocking light emitted from the backlight.

In such a liquid crystal panel, various inspections are performed after completion. For example, in a visual inspection performed by lighting a panel, the presence or absence of a point defect, a line defect, an unevenness defect, and the like are inspected. Some of the defects found here are called bright spot defects. This refers to a pixel that always displays white in a normally white liquid crystal panel (light transmission when the power is off). Pixels having such a bright spot defect (hereinafter, referred to as pixels)
The bright point pixel) is recognized as a white point particularly when black display is performed, and thus may be defective depending on the number. Normally, such a bright spot pixel is blackened by repair so that it becomes a pixel irrelevant to display.

Conventionally, as a repair method for blackening a bright spot pixel, in the case of a liquid crystal panel of normally white display,
By irradiating the PI alignment film inside the panel with laser light from the outside of the liquid crystal panel and breaking it, the orientation of the liquid crystal molecules inside the panel is disturbed, so that even if a voltage is applied between the electrodes sandwiching the liquid crystal, it will not be applied. However, there is an orientation disturbing method for shielding light. For example, in FIG. 6, a portion indicated by "A" is a repaired portion of the PI alignment film.

[0006] As a similar destruction method, there is a method of irradiating a color filter element with a laser beam to change the color of the element (blackening) so that light is not transmitted regardless of the voltage of the pixel electrode.

[0007]

By the way, since the repair of the bright spot pixel by the laser beam as described above is performed by fine processing in the visual field of the microscope, if the irradiation position is shifted, light leakage occurs and the repair effect is lost. Sometimes. In addition, since there is a portion on the array substrate where circuit characteristics change when laser light is irradiated, the irradiation range of the laser light may be limited. Further, fluctuations in the output of the laser power may cause the liquid crystal panel to break down below a specific film (for example, a PI alignment film), resulting in a defective liquid crystal panel. As described above, in the repair using the conventional laser beam, such a repair failure causes a decrease in yield.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrode substrate, a display panel, and a method of repairing the same, which are capable of reducing the repair failure due to the laser beam and improving the yield without being affected by the fluctuation of the output of the laser beam or the processing accuracy. Is to provide.

[0009]

In order to achieve the above-mentioned object, according to the present invention, a plurality of scanning lines and a plurality of signal lines intersecting each other on a main surface, and an intersection of these two lines are provided. A switch element disposed, a pixel electrode connected to the signal line via the switch element, an auxiliary capacitor electrically connected in parallel with the pixel electrode, and an auxiliary capacitance line for supplying a predetermined potential to the auxiliary capacitance Connecting a redundant circuit composed of a pair of redundant wirings stacked via an insulating layer to a path through which a data signal supplied to the signal line reaches the pixel electrode, and short-circuiting the redundant circuit. Thus, only a predetermined DC voltage is applied to the pixel electrode.

In a preferred embodiment, one redundant wiring constituting the redundant circuit is connected to a drain electrode wiring side of the switch element, and the other redundant wiring is connected to the auxiliary capacitance line.

According to a second aspect of the present invention, in the first aspect, the redundant circuit is connected in parallel with the auxiliary capacitance.

According to a third aspect of the present invention, in the second aspect, when the redundant circuit is short-circuited, a DC voltage supplied to the auxiliary capacitance line is always applied to the pixel electrode through the redundant circuit. .

According to a fourth aspect of the present invention, in the first aspect, the redundant circuit is connected between a drain line of the switch element and a scanning line.

According to a fifth aspect of the present invention, in the fourth aspect, the short circuit of the redundant circuit causes a scan signal supplied to the scan line to be constantly applied to the pixel electrode through the redundant circuit.

As a preferred mode, a redundant circuit composed of a pair of redundant wirings laminated via an insulating layer is connected between the drain wiring of the switch element and the scanning line.

In this case, due to the short circuit of the redundant circuit,
A scanning signal supplied to the scanning line is applied to the pixel electrode.

According to another aspect of the present invention, there is provided an electronic apparatus comprising:
According to the invention, a first electrode substrate comprising the electrode substrate according to claim 1 and a second electrode provided with a counter electrode on a main surface thereof are opposed to each other, and a light modulation layer is sandwiched between the two substrates. A display panel characterized in that:

In a preferred embodiment, the light modulating layer is a liquid crystal layer and is configured as a normally white display liquid crystal panel.

In a preferred embodiment, a predetermined DC voltage is constantly applied to the pixel electrode to reduce the light transmittance of a pixel corresponding to the pixel electrode by at least 90%.

According to a seventh aspect of the present invention, in the display panel according to the sixth aspect of the present invention, the redundant circuit connected to a specific pixel is illuminated with light to provide the pair of redundant wirings. Is a method for repairing a display panel.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a liquid crystal panel and a repair method thereof will be described below with reference to the drawings.

FIG. 5 is a circuit diagram of a liquid crystal panel according to the present embodiment. The liquid crystal panel 100 includes a display pixel portion 110 in which a plurality of display pixels 10 are formed, a scanning line driving circuit 120, and a signal line driving circuit 130.

In this embodiment, a drive circuit integrated type liquid crystal panel 100 in which a display pixel portion 110, a scanning line drive circuit 120, and a signal line drive circuit 130 are integrally formed on an array substrate 101 will be described as an example. However, the scanning line driving circuit 120 and the signal line driving circuit 130 may be of an external type.

The display pixel section 110 includes a plurality of signal lines 1.
1 and a plurality of scanning lines 12 intersecting the same are arranged in a matrix, and a TFT (thin film transistor) 13 as a switching element is arranged near an intersection of the two lines. The signal lines 11 and the scanning lines 12 are electrically insulated by an insulating film (not shown).

The TFT 13 has a source electrode connected to the signal line 11 and a drain electrode connected to the pixel electrode 14. The counter electrode 1 arranged in parallel with the pixel electrode 14
5 is formed on a counter substrate (not shown). A liquid crystal 16 is sandwiched between the pixel electrode 14 and the counter electrode 15 to form a capacitance Clc. Further, an auxiliary capacitor 17 is connected to the pixel electrode 14 in parallel to maintain a potential relationship with the counter electrode 15. The auxiliary capacitance 17 forms a capacitance Cs between the pixel electrode 14 and the auxiliary capacitance line 18. The storage capacitor line 18 is electrically connected to the storage capacitors 17 of all the display pixels 10, and
Supplies a constant DC voltage.

The opposing electrode 15 is provided on the drive circuit board 1.
From 40, a constant common voltage (Vcom) is applied through a common wiring (not shown). The data signal sampled on the signal line 11 is held for one frame scanning period by the capacitors Clc and Cs.

The scanning line driving circuit 120 includes a shift register and a buffer circuit (not shown), and sequentially outputs a scanning signal to each scanning line 12 based on a vertical synchronizing signal and a vertical clock signal supplied from the driving circuit board 140. I do.

The signal line driving circuit 130 includes a shift register (not shown), a video bus, a sampling switch, and the like. Each sampling switch is connected to the signal line 11, and the shift register is
The sampling switch is controlled based on the horizontal synchronization signal and the horizontal clock signal supplied from the drive circuit board 140, and the data signal supplied from the drive circuit board 140 is sampled on the signal line 11 at a predetermined timing.

The drive circuit board 140 is composed of a control IC, a D / A converter, and the like (not shown). Outputs analog data signals, horizontal / vertical clock signals, start signals, common voltages, etc. This drive circuit board 14
0 and the array substrate 100 are electrically connected by an unillustrated FPC (flexible wiring substrate).

In FIG. 5, when a data signal is sequentially output from the signal line driving circuit 130 to the signal line 11 and a scanning signal is output from the scanning line driving circuit 120 to the scanning line 12 in synchronization with this, one horizontal All T's on the line
When the FT 13 is turned on, the data signal sampled on the signal line 11 is written to a predetermined display pixel 10 via the TFT 13. The written data signal is charged between the pixel electrode 14 and the counter electrode 15 as a signal voltage, and the liquid crystal 16 responds to the signal voltage, whereby a gradation display according to the signal voltage is performed. Note that the liquid crystal panel 100 of the present embodiment is a liquid crystal panel of a normally white display. Therefore, the repair of the bright spot pixel is an operation of turning the pixel into a dark spot.

[Embodiment 1] FIG. 1 is a partially enlarged view of the liquid crystal panel 100 shown in FIG. 5, and is an equivalent circuit diagram of a display pixel 10 in Embodiment 1.

In the display pixel 10 of Embodiment 1, TF
The gate electrode (G) side of T13 is connected to the scanning line 12,
The source electrode (S) side is connected to the signal line 11, the drain electrode (D) side is connected to the storage capacitor 17 and the pixel electrode 14, and further connected to the first redundant wiring 21. One electrode of the auxiliary capacitance 17 is connected to an auxiliary capacitance line 18, and the auxiliary capacitance line 18 is connected to a second redundant wiring 22 which is disposed opposite to the first redundant wiring 21 via an insulating layer 23. Have been. The first redundant wiring 21, the second redundant wiring 22, and the insulating layer 23 form a redundant circuit 20, and the redundant circuit 20 is electrically connected to the auxiliary capacitance 17 in parallel. The first redundant wiring 21 is, for example, p
−si can be used, and, for example, MoW can be used as the second redundant wiring 22.

FIG. 2 is a schematic sectional view of the redundant circuit 20. The first redundant wiring 21 and the second redundant wiring 22 are stacked and arranged so as to face each other in a plane with the insulating layer 23 interposed therebetween. The thickness of the insulating layer 23 is, for example, 500 °.

Next, the display pixel 1 configured as described above is used.
A repair method when a bright spot defect occurs at 0 will be described.

Normally, since the first redundant wiring 21 and the second redundant wiring 22 are electrically disconnected by the insulating layer 23, when the scanning line 12 goes high and the TFT 13 turns on, the signal line 11 The sampled data signal is applied to the pixel electrode 14 through the TFT 13 to perform display. At this time, the data signal is also applied to the auxiliary capacitor 17 to perform an operation of compensating for the electric charge discharged from the pixel, thereby suppressing a change in display luminance. Therefore, the display pixel 10
If there is no bright spot defect, the first redundant wiring 21 and the second redundant wiring 22 remain electrically cut off by the insulating layer 23, so that the gradation display by the application of the data signal as described above is performed. Will be done.

On the other hand, when a bright spot defect occurs in the display pixel 10, repair is performed by irradiating a laser beam (for example, YAG-LASER) in order to make the bright spot pixel dark.

In this case, the position to be irradiated with the laser beam is indicated by reference numeral 200 in FIG. 1, that is, as shown in FIG. 2, the first redundant wiring 21 and the second redundant wiring 22 are stacked and arranged. Where you are. When this part is irradiated with the laser light 201, the second redundant wiring 22 is deformed by the laser light 201 toward the first redundant wiring 21 as shown in FIG.
The second redundant wiring 22 and the first redundant wiring 21 are electrically contacted and short-circuited. Thus, the DC voltage supplied to the auxiliary capacitance line 18 is always applied to the pixel electrode 14. That is, the first redundant wiring 21, the second
By irradiating the laser beam 201 to the redundant circuit 20 including the redundant wiring 22 and the insulating layer 23, the first redundant wiring 21
And the pixel electrode 14 is constantly supplied with D through the second redundant wiring 22.
C voltage can be applied. As described above, constantly applying a DC voltage to the liquid crystal 16 means that in a liquid crystal panel of normally white display, pixels are always kept in a light-shielded state. Thus, TFT1
By disabling the optical shutter function of the liquid crystal 16 by 3, it becomes possible to turn off the bright spot pixels, and it is possible to obtain a liquid crystal panel having no bright spot pixels.

For example, in a state where the first redundant wiring 21 and the second redundant wiring 22 are insulated from each other by the insulating layer 23, + 15V is applied to the auxiliary capacitance 17, and 5V (± 4V) is applied to the pixel electrode 14.
, The redundant circuit 20 is short-circuited by the laser light 201, so that the pixel electrode 14
Will be boosted. Here, 5 V is applied to the counter electrode 15.
Assuming that a constant DC voltage is applied, a voltage of 15 V−5 V = 10 V is constantly applied to the liquid crystal 16. As a result, it is possible to turn off the bright spot pixels in the normally white liquid crystal panel.

In this embodiment, the repair work can be made more efficient because there is no influence on the output fluctuation of the laser beam or the processing accuracy. Further, the success or failure of the repair is not affected by the magnitude of the laser beam output, so that the repair success rate is greatly increased, so that the repair failure can be reduced and the yield can be improved.

Second Embodiment FIG. 4 is a partially enlarged view of the liquid crystal panel 100 shown in FIG. 5, and is an equivalent circuit diagram of a display pixel 10 according to a second embodiment. 1 will be described with the same reference numerals.

In FIG. 4, the gate electrode (G) side of the TFT 13 is connected to a scanning line 12, and this scanning line 12
Further, it is connected to the first redundant wiring 21. On the other hand, the drain electrode (D) side is connected to the auxiliary capacitance 17 and the pixel electrode 14, and further connected to the second redundant wiring 22 which is disposed to face the first redundant wiring 21 via the insulating layer 23. . The first redundant wiring 21, the second redundant wiring 22, and the insulating layer 23 form a redundant circuit 40. Also in this embodiment, when the portion indicated by the reference numeral 400 is irradiated with laser light, the second redundant wiring 42 and the first redundant wiring 41 are electrically contacted and short-circuited as in the case of FIG. Will be. Thus, the scanning signal supplied to the scanning line 12 flows to the pixel electrode 14 through the redundant circuit 40. Assuming that a constant DC voltage of 5 V is applied to the counter electrode 15 and the gate voltage is 15 V when turned on and −2 V when turned off, the liquid crystal 16 has a D of 7 V substantially constantly (when the gate voltage is turned off).
C voltage can be applied. Thus, TF
By disabling the optical shutter function of the liquid crystal 16 by T13, it is possible to turn off the bright spot pixels, and it is possible to obtain a liquid crystal panel having no bright spot pixels. Further, in the present embodiment, by setting the portion to be short-circuited by the laser beam on the back side of the black matrix, the short-circuited portion can be made invisible on the pixel layout.

In each of the above embodiments, a predetermined pixel is short-circuited by irradiating a laser beam, and a DC voltage is constantly applied to the liquid crystal, thereby turning off the bright pixel. The light transmittance of the pixel differs depending on the DC voltage applied to the liquid crystal. Therefore, in order to obtain the effect of the dark spot, it is desirable to reduce the light transmittance of the bright spot pixel by at least 90%, and therefore, it is necessary to appropriately set the magnitude of the DC voltage applied to the liquid crystal. .

[0043]

As described above, according to the present invention,
Due to the short circuit of the redundant circuit due to light irradiation, D
Since the bright spot pixel is turned off by applying the C voltage, the output fluctuation and processing of the laser light are reduced as compared with the conventional method in which the bright spot pixel is turned off by film destruction by light irradiation. The output margin of the laser beam can be increased without being affected by the accuracy. Therefore, it is not necessary to control the output of the laser beam with higher precision than in the conventional method, and the repair work can be made more efficient. Also,
Compared with the conventional method in which the magnitude of the laser light output determines the success or failure of the repair, the repair failure can be greatly reduced, and the yield can be improved.

[Brief description of the drawings]

FIG. 1 is an equivalent circuit diagram of a display pixel including a redundant circuit according to a first embodiment.

FIG. 2 is a schematic sectional view of the redundant circuit shown in FIG.

FIG. 3 is a schematic cross-sectional view when the redundant circuit shown in FIG. 2 is irradiated with laser light.

FIG. 4 is an equivalent circuit diagram of a display pixel including a redundant circuit according to the second embodiment.

FIG. 5 is a circuit configuration diagram of a liquid crystal panel according to the embodiment.

FIG. 6 is a schematic sectional view showing the structure of a general liquid crystal panel.

[Explanation of symbols]

10: display pixel, 11: signal line, 12: scanning line, 13:
TFT (thin film transistor), 14 ... pixel electrode, 15 ...
Counter electrode, 16 liquid crystal, 17 auxiliary capacitance, 18 auxiliary capacitance line, 20, 40 redundant circuit, 21, 41 first redundant wiring, 22, 42 second redundant wiring, 23, 43 insulating Layer, 27: source electrode side wiring, 200, 400: irradiation position of laser beam

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Claims (7)

[Claims] 1. A plurality of scanning lines and a plurality of signal lines crossing each other on a main surface, a switch element disposed at each intersection of these two lines, and connected to the signal line via the switch element. A pair of redundant wirings stacked via an insulating layer on an electrode substrate including a pixel electrode, an auxiliary capacitor electrically connected in parallel with the pixel electrode, and an auxiliary capacitance line for supplying a predetermined potential to the auxiliary capacitor; A redundant circuit consisting of: a data signal supplied to the signal line is connected to a path leading to the pixel electrode, and the redundant circuit is short-circuited.
An electrode substrate, wherein only a predetermined DC voltage is applied to the pixel electrode. 2. The electrode substrate according to claim 1, wherein said redundant circuit is connected in parallel with said storage capacitor. 3. The electrode substrate according to claim 2, wherein a short-circuit of the redundant circuit causes a DC voltage supplied to the auxiliary capacitance line to be constantly applied to the pixel electrode through the redundant circuit. 4. The electrode substrate according to claim 1, wherein the redundant circuit is connected between a drain wiring of the switch element and the scanning line. 5. The electrode substrate according to claim 4, wherein a scan signal supplied to the scan line is constantly applied to the pixel electrode through the redundant circuit due to the short circuit of the redundant circuit. 6. A first electrode substrate comprising the electrode substrate according to claim 1 and a second electrode provided with a counter electrode on a main surface are opposed to each other, and a light modulation layer is sandwiched between the two substrates. A display panel, comprising: 7. The display panel repair method according to claim 6, wherein the redundant circuit connected to a specific pixel is irradiated with light to short-circuit the pair of redundant wires.