JP2002072232A - Liquid crystal display apparatus and method of manufacturing liquid crystal display apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display apparatus provided with a function for effectively preventing electrostatic destruction during manufacture. SOLUTION: The liquid crystal display apparatus provided with an active matrix type image display part is characterized in being provided with a first short ring for short-circuiting each terminal of switching elements which constitute the image display part and second short ring for short-circuiting each terminal of the switching elements, positioned in an inner side of the first short ring, in an outer peripheral part of the liquid crystal display device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device having a function of protecting against static electricity generated in a manufacturing process of an active matrix type liquid crystal display device having a built-in driver.

[0002]

2. Description of the Related Art In recent years, active matrix type liquid crystal display devices have become mainstream. An active matrix type liquid crystal display device includes two substrates and a liquid crystal sandwiched between the two substrates. On one substrate, a switching element for each pixel arranged in a matrix and a pixel electrode connected to the switching element are provided. On the other substrate, opposed electrodes corresponding to the respective pixel electrodes are provided. The display is controlled by irradiating the back surface of the liquid crystal with a backlight and applying a predetermined display voltage between each pixel electrode and the counter electrode to change the alignment state of the liquid crystal sandwiched between both electrodes to each pixel. It is changed every time, and the amount of light transmitted through the liquid crystal is controlled.

As the switching element, a non-linear element such as a thin film transistor (hereinafter, referred to as TFT) or a diode is used. Among them, a polysilicon TFT which can be formed integrally with a drive circuit of a display device and has a high response speed is often used.

In the above-mentioned active matrix type liquid crystal display device, static electricity may be generated during its manufacture. When high-voltage static electricity is generated, the gate wiring, the source wiring, the TFT, the wiring and the interlayer insulating film between the elements may be broken.

[0005] In order to prevent destruction due to static electricity generated during the manufacturing, a conventional TFT active matrix liquid crystal display device without a driver is provided with a protection circuit against static electricity. The protection circuit is configured by, for example, a pattern wiring having a large wiring capacitance that short-circuits all data lines and gate wirings along the periphery of the image display area. By employing this configuration, high-voltage static electricity generated during the manufacturing process is prevented from being applied to the internal circuit, and the internal circuit is prevented from being destroyed.

In order to effectively prevent electrostatic destruction during the manufacturing process, it is necessary to provide the above-described protection circuit at the earliest possible manufacturing stage. In addition, the protection circuit must be removed so that the device operates normally before the final stage of the manufacturing process or before an electrical test is performed in the middle of the manufacturing process.

[0007] For example, Japanese Patent Application Laid-Open No. 7-181516,
A protection circuit for a display device disclosed in Japanese Patent Application Laid-Open No. 7-175086 or the like includes a pattern wiring that short-circuits all source wirings and gate wirings via mounting terminals along the edge of the substrate outside the mounting terminals. It consists of. The protection circuit is separated when the substrate of each active matrix type liquid crystal display device is separated from the substrate along a separation line called a scrub line, or at the time of polishing the end face of the panel after the separation. By employing this structure, the protection circuit is cut off until the completion of each wiring to prevent electrostatic breakdown of the semiconductor device.

[0008]

In the above conventional method,
After cutting from the substrate, electrostatic breakdown of the liquid crystal display device cannot be prevented. In addition, when the above-described conventional method is applied to a liquid crystal display device with a built-in driver, the following problem occurs. In the case of an active matrix type liquid crystal display device incorporating a general driver, the driver is formed around an image display unit (liquid crystal panel). A large number of TFTs and wiring constituting the driver use the same metal as the gate electrode of the TFT constituting each pixel in the image display area, a semiconductor film, a metal film such as Al as the source electrode, and an interlayer insulating film. Formed. For this reason, it is very difficult to form a protection circuit (wiring pattern) using the same metal and semiconductor film as the gate electrode, the same metal film as the source electrode, and the like on the outer peripheral portion of the driver on the substrate surface.

The present invention is applicable to an active matrix type liquid crystal display device with a built-in driver, and provides an active matrix type liquid crystal display device having a function of more effectively preventing electrostatic breakdown during manufacturing. The purpose is to do.

[0010]

A first liquid crystal display device according to the present invention is an active matrix type liquid crystal display device, and each of switching elements constituting an image display section is provided at an outer peripheral portion of the liquid crystal display device. A first short ring that short-circuits a terminal; and a second short-circuit that is located inside the first short ring and short-circuits each terminal of the switching element.
Characterized by having a short ring.

The second liquid crystal display device according to the present invention comprises the first liquid crystal display device.
Wherein at least one of the first short ring and the second short ring is an integrated circuit that short-circuits each terminal of the switching element.

In the second method of manufacturing a liquid crystal display device, the first short ring and the second short ring may be sequentially short-circuited with the terminals of the manufactured switching elements as the switching elements are manufactured. It is characterized by being manufactured while wiring.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (1) Summary of the Invention In the liquid crystal display device of the present invention, the terminals of the switching elements of each pixel of the liquid crystal display device which are removed when the liquid crystal display device is separated from the substrate are short-circuited. A first feature is that a first short ring is provided, and a second short ring that can be cut by a laser is further provided inside.
By providing the first short ring, it is possible to prevent electrostatic breakdown during manufacturing of the liquid crystal display device. Further, by cutting off the laser cutting of the second short ring until immediately before the electrical inspection of the liquid crystal display device, the liquid crystal display device is divided from the substrate,
Electrostatic breakdown can be prevented until immediately before an electrical test is performed.

A second feature is that at least one of the first and second short rings is not a pattern wiring but an integrated circuit formed during the manufacture of the switching element. More specifically, of the first short ring and the second short ring, a short ring composed of an integrated circuit is manufactured as an integrated circuit that sequentially short-circuits the terminals of the manufactured switching element in connection with the manufacturing of the switching element. I do. By manufacturing at least one of the first and second short rings by this method, it is possible to effectively prevent electrostatic breakdown during the manufacturing process of the switching element. Further, by using the first and second short rings as integrated circuits, for example, the first and second short rings are also used in a liquid crystal display device having a driver around an image display unit (liquid crystal panel). Can be provided.

(2) Embodiment FIG. 1 shows a liquid crystal display device 10a, 10 according to an embodiment.
b,... are substrates made of one sheet of glass or quartz, etc.
It is a figure showing the state where a plurality was formed in the shape of a matrix above. Since the liquid crystal display devices 10a, 10b,... Have the same configuration, only the liquid crystal display device 10a will be described below. The liquid crystal display device 10a includes a first short ring 13 at the outermost periphery (however, the scrub line 12 located on the same line is shown by a dotted line in this drawing), and a second short ring 14 inside. . The first short ring 13 of the liquid crystal display device 10a is connected to the first short ring of the adjacent liquid crystal display devices 10b,. The configurations of the first short ring 13 and the second short ring 14 will be described later in detail.

The substrate 11 has a scrub line 1 indicated by a dotted line.
2 cut along. Each of the divided liquid crystal display devices 10a, 10b,... Is subjected to panel chamfering as necessary. By the cutting process and the chamfering process, the first short ring 13 included in each liquid crystal display device 10a is removed.

FIG. 2 is a top view of the liquid crystal display device 10 a formed on the substrate 11. The image display unit 21 includes a large number of pixel units arranged in a matrix (in the figure, a pixel unit 41 which is one of a large number of pixel units is shown). Pixel section 4
1 includes a pixel electrode 36 for driving a liquid crystal and a TFT 40 as a switching element. Gate drive circuit 24
a and 24b are connected to the gate wirings 22a and 22b of the TFT of each pixel unit of the image display unit 21. The source drive circuit 25 is a circuit that outputs image data input via the mounting terminal unit 42 to the image display unit 21,
1 is connected to the source wiring 23 of the TFT in each pixel portion. The precharge circuit 26 is connected to the source line 23 and boosts the source line to a predetermined voltage before supplying a source signal.

FIG. 3 is a view showing a cross section of a pixel section 41 which is one of a large number of pixel sections of the image display section 21. The cross-sections of the different components are marked with different hatchings to make them easier to distinguish. The pixel portion 41 includes a pixel electrode 3 for driving liquid crystal.
6, and a TFT 40 as a switching element. A semiconductor film 31 for forming a channel layer and a gate insulating film 3 are formed on an insulating substrate 11 such as glass or quartz.
2 are stacked. As the semiconductor film 31, a polysilicon thin film or a CG (= Continuous Grain; abbreviation for continuous grain boundary crystal) silicon thin film is used. As a result, the electron mobility is increased, the ability to flow current is increased, and the responsiveness of the screen can be improved. On the gate insulating film 32,
For example, a gate wiring 33 made of a polysilicon film or the like is provided. In the source region of the semiconductor film 31, a source wiring 34 made of a metal film such as Al is provided with a contact hole 34a penetrating the gate insulating film 32 and the first interlayer insulating film 37.
Connected through. On the other hand, a relay film 35 made of a metal film such as Al is connected to the drain region of the semiconductor film 31 via a contact hole 35a penetrating the gate oxide film 32 and the first interlayer insulating film 37. The relay film 35 is connected to a transparent pixel electrode 36 such as ITO through a contact hole 39 penetrating the second interlayer insulating film 38.

FIG. 4 is a top view showing the first short ring 13 and the second short ring 14 provided at the position of the frame 100 in FIG. FIG. 5 is a cross-sectional view of FIG.
It is A 'sectional drawing. For easy understanding, in FIGS. 4 and 5, the same components as those of the pixel portion (see FIG. 3) are the same as those shown in the cross section of each component in FIG. It is indicated with a pattern.

The first short ring 13 has two parallel wirings connected to each other with a width of 10 μm along the scribe line 12. As shown in FIG. 5, the first short ring 13 is made of the same thin film as the semiconductor film 31 on which the channel layer is formed, the same thin film as the gate wiring 33 made of a polysilicon thin film, or a metal film such as Al. It has a multilayer structure in which the constituent thin film having the same structure as the source wiring 34 and the ITO thin film 36 are sequentially short-circuited (connected to each other at a place different from the place shown in FIG. 5) in accordance with the manufacturing (lamination step). The first short ring 13 is connected to a first short ring of an adjacent liquid crystal display device formed on a substrate. By adopting this configuration, the charge accumulated on the substrate 11 during manufacturing can be attenuated to protect the pixel portion.

First short ring 13 and mounting terminal 4
2 is connected via the same constituent thin film as the semiconductor film 31 on which the channel layer is formed. Here, the thin film having the same structure as the semiconductor film 31 on which the channel layer which is the connection wiring between the first short ring 13 and the mounting terminal portion 42 is formed is formed by the liquid crystal display device 10 a being arranged along the scribe line 12 from the substrate 11. It is removed together when the panel is separated, or during the polishing process of the panel end face after the separation.

The second short ring 14 has the same thin film structure as the semiconductor 31 on which the channel layer is formed, the same thin film structure as the gate wiring 33 made of a polysilicon film or the like.
It is formed using the same constituent thin film as the source wiring 34 made of a metal film such as l. Similarly to the first short ring 13, the second short ring 14 is manufactured as an integrated circuit that short-circuits the terminals of the manufactured TFT as the TFT serving as the switching element is manufactured. The second short ring 14 and the mounting terminal 42 are connected via the same constituent thin film as the source wiring 34 made of a metal film such as Al.
Particularly, each mounting terminal is short-circuited by a 10 μm wiring. By cutting the second short ring 14 by collectively irradiating a laser beam along a dotted line 101 in the drawing, an electrical inspection of the liquid crystal display device 10a becomes possible.

The thin film having the same structure as the gate wiring 33 made of a polysilicon film or the like is not connected to the mounting terminal portion 42, and the potential is changed by the capacitance of the terminal to the second short ring 14.
And the same potential.

Next, the structure of the first short ring 13 and the second short ring 14 will be further described with reference to another place of the liquid crystal display device 10a. FIG.
FIG. 3 is a view showing a first short ring 13 and a second short ring 14 located in a portion of a frame 200 in FIG. 2. FIG. 7 is a sectional view taken along the line BB 'of FIG. For the sake of easy understanding, in FIGS. 6 and 7, the same components as those of the pixel portion (see FIG. 3) are the same as those shown in the cross section of each component in FIG. 3. It is indicated with a pattern.

The first short ring 13 is provided with two parallel wirings having a width of 10 μm and connected to each other along the scribe line 12. The first short ring 13 provided at this location is made of a thin film having the same structure as the semiconductor film 31 on which the channel layer is formed, a thin film having the same structure as the gate wiring 33 made of a polysilicon film, or a metal film such as Al. The thin film having the same structure as the source wiring 34 and the ITO thin film 36 as a transparent electrode are sequentially short-circuited (connected to each other at a position different from the position shown in FIG. 7) in accordance with the production (lamination process) thereof. Having a structure. Also,
The first short ring 13 is also connected to the first short ring of the adjacent liquid crystal display device formed on the single substrate 11. By employing this configuration, the charge accumulated on the substrate 11 during the manufacturing process can be attenuated to protect the pixel portion.

The second short ring 14 has the same thin film structure as the semiconductor film 31 on which the channel layer is formed, the same thin film structure as the gate wiring 33 made of a polysilicon thin film,
It is connected to a source wiring 34 made of a metal film such as Al. Similarly to the first short ring 13, the second short ring 14 is manufactured as an integrated circuit that short-circuits the terminals of the manufactured TFT as the TFT serving as the switching element is manufactured. The same constituent thin film as the semiconductor film 31 on which the channel layer is formed is a high-resistance wiring arranged so as to surround the periphery of each liquid crystal display device with a wiring as thick as possible. Accordingly, it is possible to suppress signal strays at the time of performing the electrical inspection performed after the second short ring 14 is cut, and maintain the reliability of the inspection.

The first short ring 13 and the second short ring 14 are connected by the same constituent thin film as the semiconductor film 33. The first short ring 13 and the second short ring 14 form a double short ring using the same constituent thin film as the semiconductor film 31. Further, the same constituent thin film as the gate wiring 33 made of a polysilicon film or the like
It is provided so as to go around the outer periphery of each liquid crystal display device. At the four corners of each liquid crystal display device, a thin film having the same structure as the source wiring 34 made of a metal film such as Al and a channel layer are formed. It is also connected to the same constituent thin film as the semiconductor film 31 (shown by a dotted line in FIG. 7). Further, by connecting to the first short ring 13 at the four corners by the same thin film as the gate wiring 33, the potential on the substrate is stabilized.

A thin film having the same structure as the gate wiring 33 made of a polysilicon film or the like which is a connection wiring between the first short ring 13 and the second short ring 14 is cut off from the substrate 11 along the scrub line 12. At the same time or during the polishing process of the panel end face after separation.

The thin film having the same structure as the source wiring 34 made of a metal film of Al or the like also functions as a common wiring which is one of the components of the driving circuit of each liquid crystal display device. The entire display device is arranged so as to be surrounded by the wiring, and is connected to the common terminal at the mounting terminal portion 42. Basically, a circuit for discharging the electric charge accumulated on the substrate 11 by the first short ring 13 is formed, and a connection portion between the first short ring 13 and the second short ring 14 (the semiconductor film 33 and the The same constituent thin film) acts as a resistor to provide a damping effect.

As described above, the first short ring 13 and the second short ring 14 having the above configuration
Is provided, the liquid crystal display device can be effectively protected from static electricity generated by friction between the manufacturing device and the insulating substrate in the manufacturing process of the liquid crystal display device.

Also, in the plasma processing performed after the liquid crystal display device is divided individually, the electric charges charged to the electrodes of the respective transistors in the liquid crystal portion can be released outside the substrate by the second short ring 14. Product properties can be significantly improved.

Further, by surrounding the outer periphery of the image display section 21 like the second short ring 14, intrusion of electric charges from the outside can be prevented.

By manufacturing the first short ring 13 and the second short ring 14 as an integrated circuit for short-circuiting the terminals of the manufactured switching element with the manufacturing of the switching element, the first short ring 13 and the second short ring 14 are manufactured during the manufacturing process of the switching element. Electrostatic breakdown can be effectively prevented.

The first short ring 13 and the second
The formation of the short ring 14, the formation of the driving element in the pixel portion forming step, and the at least partial formation of the driver circuit in the driver forming step at the same time in the same step, thereby simplifying the manufacturing process and reducing the cost. Can be achieved.

The first short ring 13 and the second short ring 13
By using the short ring 14 as an integrated circuit, the present invention can be applied to, for example, an active matrix type liquid crystal display device with a built-in driver which includes a driver around an image display unit (liquid crystal panel).

In the liquid crystal display device having the above structure, the defect rate such as dot defect due to electrostatic breakdown can be greatly reduced, so that the productivity is improved, and as a result, the manufacturing cost can be reduced. This makes it possible to manufacture a small, high-definition, high aperture ratio TFT substrate for a transmission type liquid crystal display device.

[0037]

According to the first liquid crystal display device of the present invention, since the first short ring is provided, it is possible to prevent electrostatic breakdown during the manufacture of the liquid crystal display device. In addition, by cutting off the laser cutting of the second short ring until immediately before the electrical inspection of the liquid crystal display device is performed, after the liquid crystal display device is divided from the substrate, the cutting is performed until immediately before the electrical inspection is performed. Electrostatic breakdown between them can be prevented.

According to the second liquid crystal display device of the present invention, at least one of the first and second short rings is manufactured in accordance with the method of manufacturing the liquid crystal display device of the present invention with the production of the switching element. By forming an integrated circuit that is manufactured while wiring the terminals of the manufactured switching elements so as to be short-circuited sequentially, the electrostatic breakdown of each element in the manufacturing process of the liquid crystal display device is more effectively reduced than in the case of using pattern wiring. Can be prevented. Further, by forming the first and second short rings as integrated circuits, the present invention can be applied to, for example, an active matrix type liquid crystal display device with a built-in driver which includes a driver around an image display portion (liquid crystal panel). Will be possible.

[Brief description of the drawings]

FIG. 1 shows a plurality of liquid crystal display devices formed on a substrate.

FIG. 2 is a front view of the liquid crystal display device.

FIG. 3 shows a sectional view of an image display unit.

FIG. 4 is a diagram showing first and second short rings provided on the outermost periphery of a liquid crystal display unit.

FIG. 5 is a sectional view taken along the line A-A ′ of the view shown in FIG. 4;

FIG. 6 is a diagram showing first and second short rings provided on the outermost periphery of a liquid crystal display unit.

FIG. 7 is a sectional view taken along the line B-B 'of FIG.

[Explanation of symbols]

 10a, 10b Liquid crystal display device 12 Scrub line 13 First short ring 14 Second short ring 21 Image display section 22a, 22b Gate wiring 23 Source wiring 24a, 24b Gate drive circuit 25 Source Driving circuit 31 Semiconductor film 32 Gate insulating film 33 Polysilicon film 34 Source wiring 35 Relay film 36 Transparent electrode 37, 38 Interlayer insulating film 40 TFT 41 Image part 42 Mounting terminal part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H092 GA59 HA04 JA24 JB22 JB31 JB79 KA04 NA14 NA29 5C094 AA21 BA03 BA43 CA19 EA04 EA05 EA10 EB02 HA08 5F110 AA22 BB02 CC01 DD02 DD03 EE09 EE37 GG02 NN19

Claims (3)

[Claims] 1. A liquid crystal display device having an active matrix type image display portion, comprising: a first short ring that short-circuits each terminal of a switching element forming the image display portion at an outer peripheral portion of the liquid crystal display device. A liquid crystal display device, comprising: a second short ring located inside the first short ring and shorting each terminal of the switching element. 2. The liquid crystal display device according to claim 1, wherein at least one of the first short ring and the second short ring is an integrated circuit that short-circuits each terminal of a switching element. Liquid crystal display device characterized by the above-mentioned. 3. A method for manufacturing a liquid crystal display device comprising the active matrix type image display unit according to claim 2, wherein: the first short ring and the second short ring
A method for manufacturing a liquid crystal display device, wherein a short ring formed of an integrated circuit is manufactured while wiring the terminals of the manufactured switching element so as to be sequentially short-circuited with the manufacturing of the switching element.