JPH11305259A - Liquid crystal display device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a static electricity removing method capable of removing static electricity charged in a liquid crystal display(LCD) device and the structure of the LCD device capable of easily removing static electricity. SOLUTION: The LCD device 1 is provided with electrodes called as common transition electrode parts 12. Each of the electrode parts 12 electrically connects a counter electrode on a counter substrate 3 to a wire on an active matrix substrate 10. A contact electrode 11 electrically connected to the electrode part 12 is arranged so as to be connected to the electrode part 12. The electrode 11 is electrically connected to a counter electrode and a TFT on the substrate 10 through the electrode part 12. At the start of each process, a probe is brought into contact with the electrode 11 to remove static electricity, the process is executed, the probe is brought into contact with the electrode 11 again at the end of the process to remove static electricity, and then a succeeding process is started.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing static electricity generated in a liquid crystal display device in a production process of the liquid crystal display device, and a structure of the liquid crystal display device for easily removing static electricity.

[0002]

2. Description of the Related Art Electrostatic breakdown of a liquid crystal display device mainly has two causes. As shown in FIG.
Static electricity is discharged to the electrodes and terminals of the liquid crystal display device 1 from the above, and the liquid crystal display device 1 becomes defective. For example, as shown in FIG. 11, when the protective film 4 attached to the glass surface on the counter substrate 3 side is peeled off or when the glass surface is cleaned with a piece of cloth, the glass surface of the liquid crystal display device 1 Static electricity is charged on the surface through frictional charging. The static electricity is induced from the counter substrate 3 by the electrostatic induction, and
, The liquid crystal material 7, and the pixel electrode 8.
Then, when the charged electric charge is discharged to the nearby ground 15, a large amount of discharge current flows at one time, so that the TFT (thin film transistor) of the liquid crystal display device 1 is destroyed.

[0003] The above problem is being solved by thoroughly instructing the worker 2 to work with an earth band and conductive shoes. Recently, there has been a lot of electrostatic breakdown due to the above reasons. This is because, as a result of the recent automation of the production process, static electricity generation elements are lurking in all stages of the process (transport, pasting, cleaning, inspection, etc.).

As a method of removing static electricity, a method of removing static electricity by using an ionized air blower is generally used. However, it is difficult to completely remove static electricity even by this removing method, and this is a cause of the above problem.

[0005]

The ionized air blower removal method has the following problems. Since the static electricity charged on the glass surface of the liquid crystal display device is removed, the static electricity cannot be removed even to the TFT inside the liquid crystal display device in a short time. As a structure of the air blower, when used for a long time, the ion balance is lost and the stability is reduced. Maintenance is always required. Due to the structure in which ions are sent by air, the effect of removing static electricity is extremely reduced as the distance increases. In some cases, it cannot be installed close to the production process. In the production process, a large or large amount of ionized air blower equipment is required, and a large capital investment is required.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and a static electricity removing method capable of reliably removing static electricity charged in a liquid crystal display device in a short time.
An object of the present invention is to provide a structure of a liquid crystal display device which makes it easy to remove static electricity.

[0007]

According to a first aspect of the present invention, there is provided a liquid crystal display device comprising: an active matrix substrate having a thin film transistor, a source wiring and a source terminal, a gate wiring and a gate terminal formed on an insulating substrate; A liquid crystal layer is sandwiched between the active matrix substrate and the counter substrate, and the counter electrode is electrically connected to the source wiring and the gate wiring. In a liquid crystal display device provided with a common transfer electrode portion to be connected, a contact electrode connected to the common transfer electrode portion is provided on the active matrix substrate.

According to a second aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, comprising the steps of:
At the beginning of each step, the contact electrode connected to the common transfer electrode portion provided on the active matrix substrate is brought into contact with static electricity removing means to remove static electricity,
Each step is manufactured, and at the end of each step, the static electricity removing means is brought into contact with the contact electrode connected to the common transfer electrode portion to remove the static electricity, and then proceed to the next step. I do.

In the method of manufacturing a liquid crystal display device according to a third aspect, when the static electricity removing means contacts the contact electrode connected to the common transition electrode portion, it simultaneously contacts a large number of source terminals and gate terminals. It is characterized by removing static electricity.

According to a fourth aspect of the present invention, in the method for manufacturing a liquid crystal display device, the static electricity removing means is a probe.

According to a fifth aspect of the present invention, in the method for manufacturing a liquid crystal display device, the static electricity removing means is a conductive rubber.

The operation of the above configuration will be described. Claim 1
With the configuration described above, by bringing the probe or the like into contact with the contact electrode, static electricity charged inside the liquid crystal display device can be removed from the counter electrode.

According to the manufacturing method of the present invention, the static electricity of the liquid crystal display device can be removed before the start of the manufacturing of each step, so that the manufacturing process of the liquid crystal display device can be carried out without causing characteristic failure. it can. Furthermore, since the static electricity of the liquid crystal display device is removed at the end of each step, the liquid crystal display device in a state where the static electricity is not charged can be transported to the next step. Since static electricity can be removed by such a simple method, the yield of the liquid crystal display device can be improved.

According to the manufacturing method of the third aspect, the static electricity of the liquid crystal display device can be more reliably removed.
The manufacturing process of the liquid crystal display device can be advanced without causing characteristic failure. Therefore, the non-defective rate of the liquid crystal display device can be improved.

According to the manufacturing method of the fourth aspect, it is possible to easily contact the contact electrode. According to the manufacturing method of the fifth aspect, the contact electrode can be easily contacted.

[0016]

(Embodiment 1) A liquid crystal display device according to Embodiment 1 will be described with reference to FIGS. FIG. 1 is a plan view of the common transition electrode portion 12 and the contact electrode 11 of the liquid crystal display device 1, FIG. 2 is a cross-sectional view taken along the line AA, and FIG.

As shown in FIG. 1, an electrode called a common transition electrode section 12 is provided at a corner of the liquid crystal display device 1. The common transition electrode portion 12 is
This is for electrically connecting the upper counter electrode 5 and the wiring on the active matrix substrate 10. The contact electrode 11 electrically connected to the common transition electrode portion 12
Is provided so as to be connected to the common transition electrode section 12 on the active matrix substrate 10. In the first embodiment, the contact electrodes 11 are provided in areas other than the display area on the active matrix substrate 10. The number and arrangement thereof can be arbitrarily set depending on the configuration of the substrate. 20 is a source terminal, 21
Is a gate terminal.

Next, referring to FIG.
The structure of the contact electrode 11 will be described. On the active matrix substrate 10, a Ta film 13 functioning as a gate wiring or a source wiring is formed. That Ta
Peripheral portion of edge of film 13 and active matrix substrate 10
An insulating film 14 is formed so as to cover the surface of the insulating film 14.
The configuration is such that the film 18 is formed. The ITO film 1
The contact electrode 11 extends to the end of the active matrix substrate 10. The contact electrode 11
May be any shape as long as the inspection jig or the inspection tool is easy to contact. Specifically, the contact electrode 11 has a diameter of 0.5 mm or a size of 0.5 mm square or more.

Then, the opposing electrode 5 provided on the opposing substrate 3 and the active matrix substrate 10 provided with the ITO film 18 are opposed to each other, and a conductive paste 17 is arranged therebetween. The counter electrode 5 on the substrate 3 and the ITO film 18 on the active matrix substrate 10 are electrically connected. Thus, the common transition electrode section 12 is configured. Further, the contact electrode 11 is connected to the counter electrode 5 and the T
It is electrically connected to the FT.

Next, a method of forming the common transfer electrode portion 12 and the contact electrode 11 will be described. First, as shown in FIG. 3A, a Ta film 13 as a material of a gate wiring is formed on an active matrix substrate 10 made of an insulating substrate made of glass or the like by a sputtering method to a film thickness of 50 nm.
It is formed with a thickness of 0 nm and is patterned by using photolithography. Thereby, the Ta film 1 as a gate wiring is formed.
3 is formed.

Next, as shown in FIG. 3B, an insulating film 14 made of silicon nitride or the like is formed into a thin film using a plasma CVD method and is patterned.

Next, although not shown, a semiconductor layer of the TFT,
When a contact layer and a pixel electrode are formed as a thin film and patterned, an ITO film 18 is formed on a portion corresponding to the common transfer electrode portion 12 and the contact electrode 11 to form the contact electrode 11. Thereafter, as shown in FIG. 2, a conductive paste 17 is formed on the ITO film 18.

On the other hand, the common transfer electrode 1
2, a counter electrode 5 made of a conductive film such as ITO is formed. The common transfer electrode section 12 and the contact electrode 11 are formed with the opposing substrate 3 and the active matrix substrate 10 facing each other.

(Embodiment 2) Next, a method for removing static electricity using a contact electrode will be described. As a probe for panel inspection of a liquid crystal display device, a pin contact type is generally used. Various inspections are performed by bringing the panel inspection probe into contact with the source and gate terminals of the panel. When a panel inspection probe is connected to a terminal, if a charge remains in the liquid crystal display device, there is a possibility that a TFT or the like is electrostatically damaged. Therefore, it is necessary to remove static electricity from the liquid crystal display device before contacting the panel inspection probe.

After the panel inspection, it is necessary to release static electricity from the contact electrodes after lifting the panel inspection probe from each source or gate terminal so that no charge remains at each terminal of the liquid crystal display device. is there.

The method for removing static electricity will be described with reference to an equivalent circuit shown in FIG. The discharge current flows to the liquid crystal in which the electric charge is accumulated by the electrostatic induction from the counter electrode 5 to the ground 15, so that the static electricity inside the liquid crystal display device can be removed.

As a specific example, FIG. 5 shows a method of removing static electricity in a panel inspection process. As shown in FIG. 5, the counter electrode probe 22 is brought into contact with the contact electrode 11 to release static electricity charged on the liquid crystal display device 1. The other end of the counter electrode probe 22 is connected to the ground. Therefore, the static electricity flows from the tip of the counter electrode probe 22 to the ground and is discharged. A conductive rubber 23 is attached to the tip of the counter electrode probe 22 to improve the contact with the contact electrode 11. As the conductive rubber 23, a rubber mixed with a carbon-based conductive filler is used, and its surface resistance is about 10 ⁵ to 10 ¹⁰ Ω. This resistance value is a resistance value necessary to suppress a sudden discharge current.

Next, as shown in FIG. 5, the opposing electrode probe 22 is pulled up from the contact electrode 11. afterwards,
As shown in FIG. 5, the panel inspection is performed by applying the panel inspection probe 25 to the source terminal 20 (or the gate terminal 21). In this example, the panel inspection probe 2
5 used a pin type. When the panel inspection is completed, as shown in FIG.
From the source terminal 20 (or the gate terminal 21).

Next, as shown in FIG. 5, the counter electrode probe 22 is brought into contact with the contact electrode 11 for about 1 to 10 seconds to release static electricity charged during the panel inspection. afterwards,
The counter electrode probe 22 is pulled up from the contact electrode 11, and the panel inspection process is completed.

Table 1 shows the experimental results obtained by this static electricity removing method.
Shown in First, an experimental method will be described with reference to FIG. The protective film 4 on the glass surface is peeled off and charged off. Then, the charge amount measuring device 24 as shown in FIG.
Is connected, and the charge amount is measured. Since the charge measuring device 24 is connected to the ground 15, the charge inside the liquid crystal display device 1 can be dropped to the ground 15. Next, the measuring device 24 was brought into contact with the source terminal 20 and the gate terminal 21, and residual charges of the source terminal 20 and the gate terminal 21 were confirmed.

[0031]

[Table 1]

As a result, at first, the contact electrode is 440n.
Although there was a charge of C (nano Coulomb), when static electricity was released from the contact electrode to the ground, the charge became 8 nC or less at the source terminal and the gate terminal. Therefore, it was confirmed that static electricity was discharged from the contact electrode.

The static electricity charged on the liquid crystal display device can be removed from the contact electrode through the common transfer electrode portion and also from the counter electrode.

Further, since a conductive rubber is attached to the tip of the counter electrode probe, a sudden discharge current can be suppressed by its resistance. Therefore, the inside of the liquid crystal display device, the TFT, and the like are not damaged by the electrostatic discharge current.

As a mechanism of the counter electrode probe, an air cylinder system, a push loader system using a cam or a servomotor, or the like can be used.

Alternatively, as shown in FIG. 7, a contact spring 28 is attached to the main body of the counter electrode probe 22. The contact spring 28 is connected to the ground 15 and discharges static electricity from the tip of the counter electrode probe 22 via the contact spring 28. The resistance of the contact spring 28 is 10 ⁵ or more.
The characteristic is about 10 ¹⁰ Ω.

Alternatively, as shown in FIG. 8, a measuring device (several kΩ or more) 26 having a constant internal resistance may be connected to a contact spring 28 attached to the main body of the counter electrode probe 22. The measuring device 26 is a voltmeter, a charge measuring device, an oscilloscope, or the like. The measuring device 26 is connected to the ground 15.

(Embodiment 3) Next, another static electricity removing method will be described. As shown in FIG.
1. The conductive rubber 30 is simultaneously applied to the source terminal 20 and the gate terminal 21 to discharge static electricity to the ground. The conductive rubber 30 has a surface resistance of 1 MΩ. In this method, as in the second embodiment, the static electricity removing method is performed before the start of the inspection and after the end of the inspection. In the second embodiment, the counter electrode probe 22 is used, but the third embodiment is different in that the conductive rubber 30 is used.

Table 2 shows the experimental results obtained by this static elimination method.
Shown in The experimental method will be described. The protective film 4 on the glass surface is peeled off and charged off. Then, the conductive rubber 30 is simultaneously applied to the contact electrode 11, the 800 source terminals 20, and the 400 gate terminals 21. Thereafter, the conductive rubber 30 is grounded, and static electricity is released to ground. A charge measuring device 24 is connected to the contact electrode 11, and measures the internal charge of the panel. Inspection of the panel lighting confirmed a characteristic failure of the liquid crystal display device.

[0040]

[Table 2]

As shown in Table 2, the contact electrodes 11, 80
By grounding the zero source terminal 20 and the 400 gate terminals 21 simultaneously, static electricity in the panel is removed,
It was confirmed that the characteristic failure of the liquid crystal display did not occur.

Next, a comparative experiment was conducted, and the experimental results are shown in Table 3. First, the protective film 4 on the glass surface is peeled off and charged by peeling. Thereafter, the contact electrodes 11, 1
The conductive rubber 30 is simultaneously applied to one source terminal or one gate terminal. Is the same as above. The number of source terminals and gate terminals that are in contact is different.

[0043]

[Table 3]

As shown in Table 3, by grounding the contact electrode, one source terminal or one gate terminal at the same time, static electricity in the liquid crystal display device is discharged. As a result, it was confirmed that electrostatic breakdown occurred and characteristic failure occurred.

As described above, by simultaneously grounding the contact electrode, many source terminals, and many gate terminals,
The static electricity in the panel is removed, and no characteristic failure of the liquid crystal display device occurs.

Further, a rapid discharge current can be suppressed by the resistance of the conductive rubber. Therefore, the inside of the liquid crystal display device, the TFT, and the like are not damaged by the electrostatic discharge current.

Similarly, the counter electrode probe 2 of the second embodiment
When 2 is brought into contact with the contact electrode 11, it is possible to remove static electricity by simultaneously contacting a large number of source terminals or gate terminals using conductive rubber or a panel inspection probe.

[0048]

By providing a contact electrode connected to the common transfer electrode portion, a probe or conductive rubber is brought into contact with the contact electrode, and static electricity charged inside the liquid crystal display device is also removed from the counter electrode. Can be.

According to the manufacturing method of the present invention, the static electricity of the liquid crystal display device can be removed before the start of the manufacturing of each step, so that the manufacturing process of the liquid crystal display device can be advanced without causing a characteristic defect. Furthermore, since the static electricity of the liquid crystal display device is removed at the end of each step, the liquid crystal display device in a state where the static electricity is not charged can be transported to the next step. Since static electricity can be removed by such a simple method, the yield of the liquid crystal display device can be improved.

[Brief description of the drawings]

FIG. 1 is a plan view of a common transition electrode portion 12 and a contact electrode 11 of the liquid crystal display device 1. FIG.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a manufacturing method of the AA cross section of FIG. 1;

FIG. 4 is an equivalent circuit illustrating a method for removing static electricity according to the present invention.

FIG. 5 is a diagram illustrating a static electricity removing method according to a second embodiment.

FIG. 6 is a diagram illustrating an experimental method by the static electricity removing method according to the second embodiment.

FIG. 7 is a diagram showing another configuration of the counter electrode probe 22.

FIG. 8 is a diagram showing another configuration of the counter electrode probe 22.

FIG. 9 is a diagram illustrating a static electricity removing method according to a third embodiment.

FIG. 10 is a diagram showing one of causes of conventional electrostatic breakdown.

FIG. 11 is a diagram showing one cause of the conventional electrostatic breakdown.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 3 Counter substrate 4 Protective film 5 Counter electrode 10 Active matrix substrate 11 Contact electrode 12 Common transition electrode part 13 Ta film 14 Insulating film 15 Ground 17 Conductive paste 18 ITO film 20 Source terminal 21 Gate terminal 22 Counter electrode Probe 23 30 Conductive rubber 24 Electric charge measuring device 25 Probe for panel inspection 26 Measurement device 28 Contact spring

Claims (5)

[Claims] An active matrix substrate having a thin film transistor, a source wiring and a source terminal, a gate wiring and a gate terminal formed on an insulating substrate, and a counter substrate having a counter electrode formed on the insulating substrate are arranged to face each other. A liquid crystal display device in which a liquid crystal layer is sandwiched between the active matrix substrate and the counter substrate, and a common transition electrode portion that electrically connects the counter electrode to the source wiring and the gate wiring is provided. A liquid crystal display device comprising: a contact electrode connected to a common transition electrode portion on the active matrix substrate. 2. The method for manufacturing a liquid crystal display device according to claim 1, wherein, at the beginning of each step, static electricity removing means is provided on a contact electrode connected to the common transition electrode portion provided on the active matrix substrate. To remove static electricity, and thereafter, perform each step of manufacturing.At the end of each step, the static electricity removing means is brought into contact with a contact electrode connected to the common transfer electrode section to remove static electricity. And then proceeding to the next step. 3. The method according to claim 2, wherein said static electricity removing means simultaneously contacts a large number of source terminals and gate terminals when contacting a contact electrode connected to said common transition electrode portion, thereby eliminating static electricity. Item 3. A method for manufacturing a liquid crystal display device according to item 2. 4. The method according to claim 2, wherein the static electricity removing unit is a probe. 5. The method according to claim 2, wherein said static electricity removing means is a conductive rubber.