KR20000000877A - Liquid crystal display device having static protecting circuit and mark examining method - Google Patents

Abstract

PURPOSE: A liquid crystal display device is provided to improve detection for a line defect of wiring and a pixel short-circuit defect. CONSTITUTION: The liquid crystal display device comprises: a transparent insulation plate(10); plural data lines(30) formed vertically on a substrate; a first earthing line(52) reiterated with a first and a second end terminals as both end terminals of the data line at the same time; a first diode connected with the data line in a forward direction around the first end terminal of the data line; a second diode connected with the data line in a reverse direction around the second end terminal of the data line.

Description

Liquid crystal display device having static electricity protection circuit and display inspection method using this circuit

The present invention relates to a liquid crystal display device having an electrostatic protection circuit and a display inspection method using the protection circuit.

A liquid crystal display device, which is a kind of flat panel display device, utilizes the characteristics of a liquid crystal whose light transmittance changes according to a voltage, and is widely used because it can be driven at a low voltage and power consumption is small.

Most of the manufacturing process of such a liquid crystal display device is performed on a glass substrate (glass). Because glass substrates are insulators, instantaneous charges cannot be dispersed below the substrate, making them very susceptible to static electricity. Therefore, an insulating film, an element, or the like formed on the glass substrate is likely to be damaged by static electricity, resulting in a defect of the liquid crystal display device.

In order to solve the problem caused by static electricity, all metal wires on the glass substrate are formed by forming a shorting bar, or an antistatic circuit using a nonlinear element is widely used. On the other hand, shorting bars and non-linear elements are also used for inspection for detecting defective panels.

Next, an electrostatic protection circuit, an antistatic method, and an inspection method of a conventional liquid crystal display will be described with reference to FIGS. 1 and 2.

1 is a wiring diagram of a conventional liquid crystal display substrate, and shows a shorting bar structure.

As shown in FIG. 1, a plurality of gate lines 20 and data lines 30 are formed on the substrate 10 in the horizontal and vertical directions to prevent static electricity. At one edge of 10) they are all connected by shorting bars 40 and 41. In this case, the shorting bar 40 connecting the data line 30 and the shorting bar 41 connecting the gate line 20 may be connected 42 together. At the end of the shorting bar 40, a test pad 60 for applying a test signal is connected.

During the manufacturing process of the liquid crystal display substrate, the shorting bar 40 is grounded to dissipate static electricity generated in the data line 30 or the gate line 20 through the shorting bar 40, thereby reducing damage caused by static electricity.

The shorting bar 40 may also be used to inspect display defects and the like in the liquid crystal display substrate.

That is, when a predetermined signal is applied to the shorting bars 40 and 41, all the pixels are turned on at the same time. However, the signals are not transmitted to the defective pixel in the data line 30, the gate line 20, or the thin film transistor. The pixels appear black.

On the other hand, in order to effectively discharge static electricity, an electrostatic protection diode 50 may be additionally connected to one or both ends of the data line 30 or the gate line 20 on each of the wirings 20 and 30.

FIG. 2 is a circuit diagram illustrating the electrostatic protection diode formed in FIG. 1, and the state connected to the ground line of the electrostatic protection diode is shown in detail.

1 and 2, diodes D1 and D2 are connected to the data lines 30 and the gate lines 20 in the forward and reverse directions, and the diodes 50 are connected to the same ground line 51. Is connected to. Therefore, the data shorting bar 40 and the gate shorting bar 41 as well as the diodes D1 and D2 are connected to each other.

In such a liquid crystal display substrate in which an electrostatic protection diode 50 is further formed, when a static electricity occurs in any one data line 30, the diode D1 connected to the data line 30 is turned on while being charged. Moves toward the ground line 51, and the charge moved along the ground line 51 turns on the diode D2 of the adjacent data line 30 to move along the adjacent data line 30. Locally generated charges gradually disappear as they move away in this manner.

Marking inspection on the substrate is done in the same manner as mentioned above.

After completion of the liquid crystal display inspection, the shorting bars 40 and 41 formed at the edge of the substrate 10 are removed by grinding along the cutting line C / L. However, in the case of a chip on glass (COG) method in which an integrated circuit (IC) is formed on the substrate 10, the shorting bars 40 and 41 are formed on the opposite side of the integrated circuit. Process is increased because it is to be removed by cutting rather than grinding.

In addition, in the case of performing the display inspection using the shorting bar, only the step before the liquid crystal module process is possible, and disconnection of the data line or short-circuit defect between pixels is difficult to inspect.

An object of the present invention is to implement a liquid crystal display device capable of inspecting substrate defects throughout all stages of the process.

Another object of the present invention is to increase the detection power against wiring defects or pixel short circuit defects.

1 is a wiring diagram illustrating a shorting bar and an electrostatic protection circuit of a conventional liquid crystal display device.

FIG. 2 is a circuit diagram illustrating a portion of the static electricity protection circuit of FIG. 1 in detail;

3 is a wiring diagram of a liquid crystal display according to a first embodiment of the present invention;

4 is a circuit diagram illustrating in detail a portion of the static electricity protection circuit of FIG. 3;

5 is a wiring diagram of a liquid crystal display according to a second exemplary embodiment of the present invention.

FIG. 6 is a circuit diagram illustrating a connection state of the static electricity protection circuit of FIG. 5.

7 is a circuit diagram illustrating a static electricity protection circuit according to a third embodiment of the present invention.

In order to achieve this problem, in the present invention, the diode is connected to the ground line and the data line overlapping both ends of the data line, the diode is connected to the first end of the data line in the forward direction, and the other second end in the reverse direction have.

It may have a second ground line overlapping both ends of the data line, wherein the diode connects the data line and the second ground line, the diode is connected in the reverse direction to the first end of the data line, and forward to the second end of the data line. It is preferable that it is done.

The forward diode and the reverse diode may further include a diode circuit connected in parallel with each other and inserted between two ground lines.

It is also possible for the even and odd data lines to be connected to other ground lines.

In the display inspection method of the liquid crystal display device having the wiring structure and the electrostatic protection diode, a test voltage is applied to the ground line to selectively apply a signal only in one direction along the data line.

It is also possible to form a potential difference between the diodes by applying high and low voltages to the two ground lines, respectively.

In order to check wiring short circuits between adjacent pixels, it is preferable to apply different voltages to different ground lines with respect to the even-numbered and odd-numbered data lines so that different inspection voltages are applied to the adjacent data lines.

As described above, in the present invention, data line disconnection and short circuit between adjacent pixels can be detected.

Then, the liquid crystal display and the display inspection method having an electrostatic discharge circuit according to an embodiment of the present invention with reference to the accompanying drawings so that those of ordinary skill in the art can be easily carried out in detail Explain.

3 is a wiring diagram illustrating an electrostatic protection circuit of the liquid crystal display according to the first exemplary embodiment of the present invention, and FIG. 4 is a circuit diagram showing the electrostatic protection circuit of FIG. 3 in detail.

3 and 4, a plurality of gate lines 20 and data lines 30 are formed on the substrate 10 in horizontal and vertical directions, and the gate lines 20 and data lines 30 are formed on the substrate 10. A driving element 70 for applying a gate signal and a data signal to the gate line 20 and the data line 30 is formed in a COG mounting manner.

In order to protect the device from static electricity, the gate lines 20 and the data lines 30 are connected to the diodes D1 and D2 in the forward and reverse directions, respectively, and the gate lines 20 or the data lines 30 are respectively connected. One or more electrostatic protection diodes connected to may be connected in series.

The diodes D1 and D2 connected to the gate line 20 and the data line 30 in the forward and reverse directions are bundled with separate ground lines 52 and 53, respectively. The pads 520, 530 is formed.

As shown in FIG. 4, the forward diode D3 and the reverse diode D5 may be connected in parallel to be inserted between the ground lines 52 and 53. As such, by connecting the diodes D3 and D5 connected in parallel in the bidirectional direction between the ground lines 52 and 53, the two ground lines 52 and 53 are connected to each other to increase the antistatic performance. That is, when static electricity is generated in any one of the data lines 30, the charge is transferred to the ground line 52 via the forward diode D1, which is tied in the forward direction to the data line 30, and then the ground lines 52 and 53. Of the diodes connected in parallel between them, the diodes D5 and D6, which are bundled in the forward direction, move to another ground line 54, and all the data lines 30 through the diodes D2 and D4 connected to the ground line 53, and the like. Spreads to) and disappears.

As such, the path through which the charge can move is sufficiently long, and capacitance is formed at the portion where the data line 30 and the ground lines 52 and 53 overlap, so that static electricity can be effectively prevented without a conventional shorting bar structure. have.

In addition, by applying different signals to the pads 520 and 530 of the ground lines 52 and 53, display inspection of the liquid crystal panel may be performed before assembling the liquid crystal display module without a separate shorting bar. That is, a predetermined potential is formed between the ground lines 52 and 53 to apply a test signal to the data line 30, and the display state of the liquid crystal panel may be inspected to determine whether the liquid crystal panel is defective.

FIG. 5 is a wiring diagram of a liquid crystal display according to a second exemplary embodiment of the present invention, in which an electrostatic protection diode is formed on the upper and lower portions of a substrate.

As described above, when the diode 50 is formed on the upper and lower portions of the substrate 10, the static electricity may quickly disappear, thereby enhancing the antistatic function.

However, since a signal is applied from above and below the data line 30 through the upper and lower diodes, it is difficult to find the disconnection defect of the data line 30.

FIG. 6 is a circuit diagram of a structure in which diode directions are differently connected at the upper side and the lower side with respect to the ground line, and a principle of detecting a data line disconnection defect by applying a signal to the ground line is shown.

As shown in FIG. 6, the lower electrostatic protection diodes D7 and D8 are connected to one end of the data line 30 in the forward and reverse directions, respectively, and the diode D7 connected in the forward direction is connected to the ground line to which 0V is applied. 53, the diode D8 connected in the reverse direction is tied to the ground line 53 to which 10V is applied. In addition, the upper antistatic diodes D9 and D10 are connected to the other end of the data line 30 in the forward and reverse directions, respectively, and the diode D9 connected in the forward direction is connected to the ground line 52 to which 10V is applied. The diode D10 connected in the reverse direction is connected to the ground line 53 to which 0V is applied.

In order to check for disconnection defects in the data line 30, when a voltage of 10 V is applied to one ground line 52 and a voltage of 0 V is applied to the other ground line 53, the data line 30 is forward and reverse to the data line 30. Connected lower diodes D7 and D8 turn on and a potential difference of 5V occurs between the diodes D7 and D8. Thus, a current of 5V is applied from one end of each data line 30. However, since the upper diodes D9 and D10 are connected in a direction different from the direction in which the lower diodes D7 and D8 are connected to the ground lines 52 and 53, the diodes D9 and D10 are not turned on from the opposite end of the data line 30. No voltage is applied.

That is, since the signal voltage for inspection is applied only in one direction of the data line 30, the signal is not transmitted across the disconnection generation point P of the data line 30, thereby easily eliminating the disconnection defect of the data line 30. Can be detected.

7 illustrates a structure in which diodes are connected to each other by odd-numbered and even-numbered lines of the data line.

As shown in FIG. 7, four ground lines 53, 54, 55, and 56 are formed to overlap in the vicinity of the ends of the data lines 31 and 32 and the gate line 20. In the manner mentioned, a diode is connected to the data lines 31 and 32. However, the even-numbered data line 32 is connected to the first and second ground lines 52 and 53, and the odd-numbered data line 31 is connected to the third and fourth ground lines 54 and 55.

In such a structure, the test signal voltage can be differently applied to the adjacent data lines 31 and 32 to detect a defect such as a short circuit between adjacent pixels.

Since the electrostatic protection circuit and the ground line in all the above-described embodiments are not removed separately like other wirings, the defect inspection of the liquid crystal substrate can be performed at any stage.

As described above, the liquid crystal display device according to the present invention is excellent in the electrostatic protection effect, the display inspection can be performed at any stage of the manufacturing process of the substrate, and the defect detection power is also improved.

Claims (15)

Transparent insulation substrate, A plurality of data lines formed vertically on the substrate, A first ground line overlapping the first and second end sides of the data line at the same time; A first diode connected to the first ground line and forwardly connected to the data line near a first end of the data line; A second diode connected to the first ground line and connected in a reverse direction to the data line near a second end of the data line; Liquid crystal display comprising a. In claim 1, A second ground line overlapping the first and second end sides of the data line, a third diode connected to the second ground line and connected in a reverse direction to the data line near the first end of the data line, and with the second ground line. And a fourth diode connected to the data line in a forward direction near the second end of the data line. In claim 2, And a circuit in which the forward diode and the reverse diode are connected in parallel to each other and inserted between the first ground line and the second ground line. In claim 2, And a first pad and a second pad, respectively, formed at one end of the first ground line and the second ground line. In claim 2, The first, second, third, and fourth diodes each of which two or more diodes are connected in series. In claim 1, A second ground line overlapping the first and second ends of the data line, a third diode connected to the second ground line and forwardly connected to the first end of the data line, and connected to the second ground line and the second of the data line Further comprising a fourth diode connected in a reverse direction to the end, And the first and second diodes are connected to the odd-numbered data lines, and the third and fourth diodes are connected to the even-numbered data lines. In claim 6, And a first circuit in which a forward diode and a reverse diode are connected in parallel to each other and inserted between the first ground line and the second ground line. In claim 6, Third and fourth ground lines overlapping with the first and second end sides of the data line, a fifth diode connected to the third ground line and connected in the opposite direction to the data line near the first end of the odd-numbered data line; A sixth diode connected to the third ground line and forwardly connected to the data line near the second end of the odd-numbered data line; and a fourth diode connected to the fourth ground line and opposite to the data line near the first end of the even-numbered data line. And a seventh diode connected to the fourth ground line and an eighth diode connected to the data line in a forward direction near the second end of the even-numbered data line. In claim 8, And a second circuit in which a forward diode and a reverse diode are connected in parallel to each other and inserted between the third ground line and the fourth ground line. In claim 8, And first, second, third, and fourth pads are formed at one end of the first, second, third, and fourth ground lines, respectively. A transparent insulating substrate, a plurality of data lines vertically formed on the substrate, a first ground line overlapping simultaneously with the first and second ends, which are both ends of the data line, and connected to the first ground line and near the first end of the data line The liquid crystal display of claim 1, further comprising a first diode connected to the data line in a forward direction, and a second diode connected to the first ground line and connected in a reverse direction to the data line near a second end of the data line. And a test voltage is applied in one direction along a data line by applying a voltage to the first ground line. In claim 11, The liquid crystal display may further include a second ground line overlapping the first and second ends of the data line, a third diode connected to the second ground line and connected in the opposite direction to the data line near the first end of the data line; And a fourth diode connected to the second ground line and forwardly connected to the data line near a second end of the data line. And applying a different voltage to the first and second ground lines, respectively, to form a potential difference between the first diode and the third diode. In claim 12, A low voltage is applied to the first ground line and a high voltage is applied to the second ground line so that a voltage for inspection is applied from the first end of the data line and no voltage is applied from the second end. Inspection method of the liquid crystal display device for inspecting. A transparent insulating substrate, a plurality of data lines vertically formed on the substrate, a first ground line and a second ground line overlapping the first and second ends, which are both ends of the data line, and connected to the first ground line and connected to the first ground line. A first diode connected in a forward direction with the odd-numbered data line near a first end, a second diode connected with the first ground line and in a reverse direction with an odd-numbered data line near a second end of the data line, the first diode A third diode connected to a second ground line and forwardly connected to the even-numbered data line near a first end of the data line; and a third diode connected to the second ground line and connected in a reverse direction to the even-numbered data line near a second end of the data line. A liquid crystal display device comprising a fourth diode, And a different signal voltage is applied to the first ground line and the second ground line to check a short circuit between the pixels. The method of claim 14, And each of the first, second, third, and fourth diodes using two or more diodes connected in series.