JP2000098426A - Active matrix substrate and liquid crystal display device using this substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress discharge of static electricity caused between an active matrix side substrate and a short-bar side substrate piece at the time of cutting a short-bar. SOLUTION: This device is provided with at least many switching elements for selecting a display pixel formed in a display region, and many scanning signal lines Gi for applying a drive signal to the switching elements and many video signal line Dj, also provided with a scanning signal line short-bar GSB coupling commonly to scanning signal lines Gi formed on an active element substrate with coupling lines GCN, and a video signal line short-bar DSB coupling commonly to video signal lines Dj with coupling lines DCN, and provided with a conduction type thin film pattern GDMY or DDMY for forming capacity with the short-bar and its coupling line at an eliminated side with a short-bar of a coupling line of at least either of a scanning signal line short-bar GSB cut and eliminated after lamination of color filter substrates CFSUB and a video signal line short-bar DSB.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix substrate having a structure for protecting active elements and the like formed on an active substrate constituting a liquid crystal display device from static electricity, and a liquid crystal display device using this substrate. .

[0002]

2. Description of the Related Art Liquid crystal displays are widely used as devices for displaying various images including still images and moving images.

In a liquid crystal display device, a layer of a liquid crystal composition (liquid crystal layer) is sandwiched between two insulating substrates, at least one of which is made of transparent glass or the like, and a pixel formed on the insulating substrate is formed. A type in which a predetermined pixel is turned on and off by selectively applying a voltage to various electrodes for use in the active element, and an active element composed of the various electrodes and a switching element such as a thin film transistor (TFT) for pixel selection is formed. Is selected, a predetermined pixel is turned on and off.

[0004] In particular, the latter type of liquid crystal display device is called an active matrix type, and has become the mainstream of the liquid crystal display device because of its contrast performance, high-speed display performance and the like.

An active matrix type liquid crystal display device is
There is known a so-called vertical electric field method in which an electric field for changing the orientation of a liquid crystal layer is applied between an electrode formed on one insulating substrate (active matrix substrate) and an electrode formed on the other substrate (color filter substrate). Have been.

On the other hand, a so-called lateral electric field type (in-plane switching type: also referred to as IPS type) liquid crystal display device in which the direction of an electric field applied to the liquid crystal layer is made substantially parallel to the substrate surface has been put to practical use. As the lateral electric field type liquid crystal display device, there is a device in which a comb electrode for applying an electric field to the liquid crystal is formed on one of two insulating substrates (active matrix substrate) to obtain a very wide viewing angle. Known (JP-B-63-21907, U.S. Pat.
249).

As described above, the liquid crystal display device includes a liquid crystal panel having liquid crystal sandwiched between a pair of insulating substrates, an external driving circuit for driving the liquid crystal panel, and various types of devices for efficiently irradiating the liquid crystal panel with illumination light. It is composed of optical elements and others.

In an active matrix type liquid crystal display device, a scanning signal line for driving a switching element such as a thin film transistor as an active element and a video signal line are provided on the active matrix substrate. A protection circuit is formed to protect the electrodes from static electricity that enters from the outside.

FIG. 4 shows a state in which a color filter substrate CFSUB is laminated on a mother substrate (a substrate before cutting into an active matrix substrate forming a liquid crystal panel) on which an active element substrate constituting a conventional active matrix type liquid crystal display device is formed. FIG. 2 is a plan view illustrating a configuration example of
Is a scanning signal line (also called a gate line GL), and Dj is a video signal line (also called a data line DL). A switching element (generally, a thin film transistor (TFT)), which is an active element, not shown, is provided near the intersection of these signal lines, and the output electrode of the switching element is a pixel electrode for applying an electric field to the liquid crystal. Connected,
Display pixels arranged two-dimensionally are formed.

[0010] Further, the G formed outside the display area.
PAD is a terminal for connecting an external drive circuit to the scanning signal line Gi, and DPAD is a terminal for connecting an external drive circuit to the video signal line Dj.

The GSB and DSB provided on the outer periphery of the mother substrate MSUB, which is preferably a glass plate, constitute an electrostatic protection circuit called a short bar. GSB is a scanning signal line short bar that electrically connects the end points or the starting points of the many scanning signal lines Gi, DSB is a video signal line short bar that electrically connects the end points or the starting points of the many video signal lines Dj, This is a line for absorbing static electricity. These short bars GSB and DSB are respectively connected to a connection line GCN,
The scanning signal lines Gi, via GPAD and DPAD in DCN,
It is connected to the video signal line Dj. CTLN is mother board M
A cutting line for separating an active matrix substrate for finally assembling a liquid crystal panel from the SUB;
In particular, CTLN1 indicates a cutting line that cuts the scanning signal line short bar GSB side. Note that the video signal line Dj is similarly disconnected.

The short bars GSB and DSB prevent damage to switching elements such as thin film transistors TFT and other electrodes due to static electricity that has entered the scanning signal lines Gi or the video signal lines Dj.

The connection between the scanning signal line Gi, the video signal line Dj, and the short bars GSB and DSB is not limited to the terminals GPAD and DPAD as shown in FIG.
D and DPAD may be performed on the opposite side or both sides, or may be alternately performed on the terminals GPAD and DPAD and on the opposite side.

[0014]

FIG. 5 shows an active matrix substrate SU in a state where the short bar is cut off by cutting along the cutting line CTLN1 on the short bar GSB side in FIG.
B side substrate CELL and short bar GSB cut and removed
FIG. 7 is a plan view of a substrate FHEN on the side.

FIG. 6 shows the active matrix substrate SUB with the short bar cut off by cutting along the cutting line CTLN1 on the short bar GSB side in FIG.
It is the side view seen from one side. After cutting and removing the short bar GSB, the terminal GPA connected to the scanning signal line Gi
The coupling line GCN on the D side is exposed at the cutting edge of the active matrix substrate. In addition, short bar GSB after cutting
The same applies to the side surface.

Along mother line MSUB along cutting line CTLN1
When cutting, a lot of static electricity is generated due to friction with a cutting tool and peeling of the substrate. The static electricity generated during this cutting is charged on both the active matrix side substrate CELL and the short bar side substrate piece FHEN. A scanning signal line Gi and a video signal line Dj are formed on the active matrix side substrate CELL, and a color filter substrate CFSUB is further formed.
Are laminated. This color filter substrate CFSUB
A common electrode is formed on the side. Therefore, the ground capacity is large.

On the other hand, the short bar side substrate piece FHE
N has only the short bar GSB and the remaining coupling line GCN, and has a small number of metal layers and a small ground capacity.

As a result, the active matrix side substrate C
Even if static electricity is charged to the ELL and the short bar side substrate FHEN at the same density, the potential of the short bar side substrate piece FHEN becomes a larger value than that of the active matrix side substrate CELL, and a large potential difference occurs between the two. For this reason, a discharge is generated from the short bar side substrate FHEN toward the active matrix side substrate CELL.

Since the exposed end of the coupling line GCN shown in FIG. 6 is sharp, an electric field due to static electricity is concentrated on the exposed end of the coupling line GCN, and discharge easily occurs between the exposed ends. Here, when the discharge occurs, a large current flows into the scanning signal line Gi or the video signal line Dj, and there is a problem that a switching element such as a thin film transistor and other electrodes are broken.

An object of the present invention is to solve the above-mentioned problems of the prior art and to suppress the discharge of static electricity generated between the active matrix side substrate CELL and the short bar side substrate piece FHEN when the short bar is cut. An object of the present invention is to provide an active matrix substrate having an electrostatic protection circuit and a liquid crystal display device using the substrate.

[0021]

According to the present invention, there is provided a short bar for preventing static electricity from entering a scanning signal line or a video signal line formed on an active matrix substrate. An active matrix substrate and a short bar side substrate which are cut by forming dummy electrodes on the short bar side substrate piece on the side to be cut and removed as the liquid crystal panel to form the same capacitance as the active matrix substrate side It is characterized in that it is configured to avoid discharge occurring between the pieces.

That is, a typical configuration of the present invention is as described in the following (1) to (3).

(1) A large number of switching elements for selecting display pixels formed in a display area, and a large number of scanning signal lines and a large number of video signal lines for applying a drive signal to the switching elements. A scanning signal line short bar in which the plurality of scanning signal lines formed on the active element substrate are commonly coupled by a coupling line; and a video signal line short bar in which the multiple video signal lines are commonly coupled by a coupling line. The short bar and the short bar on the side of at least one of the scanning signal line short bar and the video signal line short bar that is cut and removed after laminating the color filter substrate together with the short bar. A conductive thin film pattern (dummy electrode) for forming a capacitance together with the coupling line was provided.

With this configuration, the capacitance on the short bar side to be cut and removed increases, and the potential difference between the short bar side and the active matrix substrate side decreases. Therefore, it is possible to prevent a discharge from being generated between the two when they are cut and removed.

(2) The conductive thin film pattern according to (1) is formed on an upper layer of an insulating film covering the short bar and its connection line.

By doing so, for example, the conductive thin film pattern can be formed simultaneously with the formation of the pixel electrodes of the active matrix substrate, and there is no need to provide a step for forming the conductive thin film pattern.

(3) The active matrix substrate according to (1) or (2) and a color filter substrate laminated on the active matrix substrate with a liquid crystal layer interposed therebetween, and a liquid crystal composition is sealed in a gap between the two. To form a liquid crystal panel, and an external drive circuit, an illumination light source,
A liquid crystal display device is assembled by incorporating other optical elements or electric elements.

In the liquid crystal display device according to the present invention obtained as described above, the electrostatic breakdown of the switching element or other electrodes in the manufacturing process is reduced, and the yield is improved.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of an active matrix substrate according to the present invention and a liquid crystal display device using the substrate will be described in detail with reference to the accompanying drawings.

FIG. 1 is a plan view for explaining a first embodiment of the active matrix substrate according to the present invention. 4 are given the same reference numerals, and Gi is a scanning signal line (G
L), Dj are video signal lines (DL), GPAD is a terminal for connecting an external drive circuit to the scanning signal line, DPAD is a terminal for connecting the external drive circuit to the video signal line, GSB
Is a short bar formed on the scanning signal line side, DSB is a short bar formed on the video signal line side, GCN is a coupling line connecting the scanning signal line Gi to the short bar GSB via the terminal GPAD, and DCN is a video signal line Dj. , Connecting GDMY to the short bar DSB via the terminal DPAD
Is a dummy electrode (conductive thin film pattern) formed on the short bar side substrate piece FHEN, MSUB is a mother substrate (mother glass substrate), CTLN is a cutting line for finally forming an active matrix substrate, and CTLN1 is an active matrix side substrate CELL and short bar GSB side substrate piece FHE
A cutting line for cutting N is shown.

In the active matrix substrate of this embodiment, the scanning signal line Gi is connected to the scanning signal line short bar GSB via the coupling line GCN, and the video signal line Dj is connected.
Is connected to the scanning signal line short bar DSB via the coupling line DCN.
Connect to Then, a dummy electrode GDMY was provided outside the cutting line CTLN1.

The coupling lines GCN and DCN and the short bars GSB and DSB can be formed simultaneously when the signal lines Gi and Dj and the terminals GPAD and DPAD are formed. The dummy electrode GDMY can be formed simultaneously with a pixel electrode (not shown) made of an ITO film formed on the active matrix side substrate CELL.

FIG. 2 is a cross-sectional view taken along the line aa of FIG. 1. PAS is a transparent conductive film. Color filter substrate CFS on mother substrate MSUB to be an active matrix substrate
After laminating UB and sealing the liquid crystal composition in the gap between them,
First, the substrate is cut along the cutting line CTLN1, and the active matrix side substrate CELL and the short bar GSB side substrate piece F are cut.
Separate into HEN.

At this time, the short bar GSB side substrate piece F
Since a dummy electrode GDMY is formed in HEN,
Active matrix substrate CELL and short bar G
Each capacitance of the SB-side substrate piece FHEN is equivalent.

FIG. 1 shows an active matrix substrate SUB.
Is cut along the cutting line CTLN. During this cutting, the short bars GSB and DSB are cut and separated and removed.

At the time of this cutting, static electricity is generated due to friction with the cutting tool and peeling of the substrate, and the active matrix substrate CELL and the short bar GSB side substrate piece FHEN are charged. Since the charged static electricity is substantially the same potential, the active matrix side substrate C
When the ELL and the short bar GSB-side substrate piece FHEN are separated, no discharge occurs between the cut connection lines GCN.

With the configuration of this embodiment, the scanning signal line G
i, static electricity does not enter the video signal line Dj, and damage to the thin film transistor TFT and other electrodes due to static electricity is prevented, and display defects are prevented.

FIG. 3 is a plan view illustrating a second embodiment of the active matrix substrate according to the present invention. In addition, b-
The cross section along the line b is the same as in FIG.

In this embodiment, the dummy electrodes shown in FIG. 1 are similarly formed on the short bar DSB side of the video signal line, and CTLN2 is composed of the active matrix side substrate CELL and the short bar DSB side substrate piece HHEN. And the same reference numerals as those in FIG. 1 correspond to the same parts.

After or before cutting the short bar GSB side substrate piece FHEN on the scanning signal line side, the active matrix side substrate CELL and the short bar DSB side substrate piece H
Separate into HEN.

At this time, the short bar DSB side substrate piece H
Since a dummy electrode DDMY is formed in HEN,
Active matrix side substrate CELL and short bar D
Each capacitance of the SB-side substrate piece HHEN is equivalent.

FIG. 1 shows an active matrix substrate SUB.
Is cut along the cutting line CTLN. At the time of this cutting, the short bar GSB side substrate piece HHEN
Is cut off and removed.

At the time of this cutting, static electricity is generated due to friction with the cutting tool and peeling of the substrate, and the active matrix substrate CELL and the short bar DSB side substrate piece HHEN are charged. Since the charged static electricity is substantially the same potential, the active matrix side substrate C
When the ELL and the short bar DSB side substrate piece HHEN are separated, no discharge is generated between the cut connection lines DCN.

With the configuration of this embodiment, the scanning signal line G
i, static electricity does not enter the video signal line Dj, and damage to the thin film transistor TFT and other electrodes due to static electricity is prevented, and display defects are prevented.

It should be noted that the present invention is not limited to the above embodiment, and various changes can be made without departing from the technical idea of the present invention.

[0046]

As described above, according to the present invention,
Since the entire periphery of the display area is surrounded by the short bar, even if static electricity enters from the direction during the manufacturing process, it can be effectively absorbed, and damage to the switching element and other electrodes is suppressed. . Therefore, according to the present invention, a liquid crystal display device with improved yield and high reliability can be provided.

[Brief description of the drawings]

FIG. 1 shows a first active matrix substrate according to the present invention.
It is a top view explaining an Example.

FIG. 2 is a sectional view taken along the line aa of FIG.

FIG. 3 shows a second embodiment of the active matrix substrate according to the present invention.
It is a top view explaining an Example.

FIG. 4 shows a configuration in which a color filter substrate CFSUB is stacked on a mother substrate on which an active element substrate constituting a conventional active matrix type liquid crystal display device is formed (a substrate before cutting into an active matrix substrate forming a liquid crystal panel). It is a top view explaining an example.

FIG. 5 is a cutting line CTLN on the short bar GSB side of FIG. 4;
1 is a plan view of a substrate CELL on the active matrix substrate SUB side in a state where the short bar is cut off by cutting at 1 and a substrate FHEN on the short bar GSB side cut and removed.

6 is a cutting line CTLN on the short bar GSB side of FIG. 4;
1 is a side view of the active matrix substrate SUB in a state where the short bar is cut off by cutting at 1 in a cut line CTLN1 side.

[Explanation of symbols]

Gi scanning signal line (GL) Dj video signal line (DL) GPAD Terminal for connecting external driving circuit to scanning signal line DPAD Terminal for connecting external driving circuit to video signal line GSB Short bar on scanning signal line side DSB Short bar on video signal line side MSUB mother board GCN Coupling line connecting scan signal line and short bar DCN Coupling line connecting short signal bar with video signal line GDMY Scan signal line side dummy electrode DDMY Video signal line side dummy electrode CTLN , CTLN1, CTLN2 Cutting lines for finally forming an active matrix substrate.

Claims (3)

[Claims] A plurality of switching elements for selecting display pixels formed in a display area; a plurality of scanning signal lines for applying a drive signal to the switching elements; and a plurality of video signal lines. A scanning signal line short bar in which the plurality of scanning signal lines formed on the active element substrate are commonly connected by a coupling line, and a video signal in which the plurality of video signal lines are commonly coupled by a coupling line. A short-circuit bar on at least one of the coupling lines of the scanning signal line short bar and the video signal line short bar which is cut and removed after laminating the color filter substrate. A conductive thin film pattern for forming a capacitance together with the bar and its connection line. Active matrix substrate. 2. The active matrix substrate according to claim 1, wherein said conductive thin film pattern is formed on an upper layer of an insulating film covering said short bar and its connection line. 3. A liquid crystal display device comprising: the active matrix substrate according to claim 1; and a color filter substrate laminated on the active matrix substrate via a liquid crystal layer.