JP2000267137A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a switching element array substrate capable of preventing dielectric breakdown of switching elements and wiring, and a liquid crystal display device using the substrate. SOLUTION: An electrode Cm and an electrode X1 are oppositely disposed across an insulating film in the neighborhood of a scanning line 1, to form a protective electrostatic capacity. An electrostatic capacity line X connected with this electrode X1 does not hinder the circuit operation on an array substrate, and is connected with common wiring having a large wiring area. Thus, the protective electrostatic capacity has a large capacitance value, and can prevent dielectric breakdown by diffusing the electric charges stored on the scanning line 1 to the protective electrostatic capacity.

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 a switching element array substrate having switching elements disposed on an insulating substrate used in a liquid crystal display device and the like.

[0002]

2. Description of the Related Art Conventionally, in the process of manufacturing a switching element array substrate used in a liquid crystal display device or the like, an excessive potential difference is generated due to static electricity or the like generated during a process, and an element on an insulating substrate is electrostatically damaged or There is a problem in that wirings that are insulated from each other with an interlayer insulating film interposed therebetween cause dielectric breakdown at intersections and are short-circuited.

Therefore, protection diodes are generally formed on various lines. However, depending on the manufacturing process, one of the lines is formed at a stage before the protection diode is formed, which may cause electrostatic breakdown.

[0004]

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention provides a switching element array substrate capable of preventing electrostatic breakdown of switching elements and wirings, and a liquid crystal display device using the substrate. With the goal.

[0005]

According to the present invention, there is provided a liquid crystal display device comprising: an insulating substrate; a plurality of rows of scanning lines and a plurality of columns of signal lines arranged so as to cross each other on the insulating substrate; A liquid crystal pixel including a plurality of pixel electrodes disposed near an intersection of the scanning line and the signal line on the substrate and a common electrode opposed to the pixel electrode via a liquid crystal layer; A switching element disposed for each of the pixel electrodes and connected to the scanning line, the signal line, and the pixel electrode; and a scanning line driving circuit formed on the insulating substrate and driving the scanning line; A plurality of protective capacitance electrodes disposed between the scanning lines so as to be electrically insulated from the scanning lines, and a protective electrostatic electrode disposed opposite to the plurality of protective capacitance electrodes via an interlayer insulating film. Capacitance wiring and Characterized by comprising the connected power supply wiring to the protection capacitance wiring.

Here, the protection capacitance electrodes may be arranged in a direction substantially perpendicular to a direction in which the scanning lines extend.

[0007] Alternatively, the protection capacitance electrode may be formed in the same layer as the scanning line.

Alternatively, the protective capacitance electrode is
It may be formed between the effective display area where the liquid crystal pixels are arranged and the scanning line drive circuit formation area.

Further, the power supply line may be a power supply line for supplying a voltage to the common electrode.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 2 shows a schematic configuration of the liquid crystal display device according to the present embodiment.

A plurality of scanning lines 1 and signal lines 23 are arranged on an insulating substrate 10 made of glass or the like so as to intersect with each other via an interlayer insulating film (not shown), and a pixel electrode 22 arranged at each intersection. Are connected to a signal line 23 via a TFT 21. The TFT 21 has a so-called staggered structure, and is formed by stacking a polycrystalline silicon semiconductor layer, a gate insulating film, a gate electrode, an interlayer insulating film, a source electrode, and a drain electrode in order from the substrate surface. The source electrode and the drain electrode are connected to a source region and a drain region formed by introducing impurities into the polycrystalline silicon semiconductor layer. The gate electrode is connected to the scanning line 1, while the drain electrode is connected to the signal line 23.

A scanning line driving circuit 25 for driving the scanning lines and a signal line driving circuit 24 for driving the signal lines are integrally formed on the periphery of the substrate 10. The scanning line driving circuit 25 and the signal line driving circuit 24 have the same layer structure as the TFT 21.

An opposing substrate (not shown) is disposed opposite the substrate 10 with a liquid crystal layer interposed therebetween, and an opposing common electrode formed on the main surface of the opposing substrate is capacitively coupled to the pixel electrode 22 via the liquid crystal layer, thereby forming a liquid crystal. A pixel.

A common wiring 26 for supplying a voltage to the opposing common electrode is formed along the outer periphery of the substrate 10. The common wiring 26 is formed in the same layer as the electrodes of the TFT 21. In the present embodiment, the common wiring 26 is formed in the same layer as the layers of these electrodes when forming the source and drain electrodes. The common wiring 26 is connected to the opposing common electrode by conductive connection means such as silver paste.

In a region between the effective display region where the liquid crystal is disposed and the scanning line driving circuit 25, a protection capacitance is disposed. FIG. 2 shows the formation position of the protection capacitance wiring X that forms the protection capacitance. As shown in FIG. 1, the protection capacitance wiring X constitutes a protection capacitance by being arranged opposite to a protection capacitance electrode arranged between adjacent scanning lines. The protection capacitance wiring X is a TFT 21
The protective capacitance electrode is formed in the same layer as the gate of the TFT 21. The protection capacitance wiring and the protection capacitance electrode are arranged to face each other with the gate insulating film interposed therebetween.

FIG. 1 shows a configuration of a protection capacitance forming portion of the liquid crystal display device according to the present embodiment. On the insulating substrate 10, scanning lines 1 in a plurality of columns and signal lines in a plurality of rows (not shown) are arranged, pixel electrodes (not shown) are arranged at intersections, and switching elements made of TFTs are provided near the pixel electrodes. Are located. The gate of the TFT is connected to the scanning line 1, the drain is connected to the signal line, and the source is connected to the pixel electrode. Further, an auxiliary capacitance Cs (not shown) is formed near the pixel electrode.

The auxiliary capacitance Cs is composed of a lower auxiliary capacitance line 2m made of molybdenum tungsten and an auxiliary capacitance line 2a made of aluminum and arranged in an upper layer via an insulating film and connected at a contact hole 2c. The auxiliary capacitance line 2 is connected.

The scanning line 1 is connected to a lower scanning line 1m made of molybdenum tungsten and an upper scanning line 1a made of aluminum connected through a contact hole 1c via an insulating film. The scanning line 1 is connected to a scanning line driving circuit (not shown) and supplies a gate signal to the gate of the TFT.

In order to diffuse the electric charge stored in the scanning line 1, an island-shaped first electrode Cm is arranged near the scanning line 1. The second electrode X1 is arranged via the first electrode Cm and the insulating film, and the first electrode Cm and the second electrode X1 constitute a protective capacitance. The protection capacitance line X is connected to the second electrode X1.

According to the present embodiment, both ends of the protection capacitance line X are connected to the common wiring. The common wiring is provided in a peripheral region of the switching element array substrate, and is a wiring for supplying a common potential to a counter electrode provided on the counter substrate, and is generally the thickest and longest wiring on the array substrate. Therefore, this is the wiring with the smallest potential variation on the switching element array substrate when a certain constant charge is applied. By connecting both ends of the wiring X to such a common wiring, a change in potential when a constant charge is applied to the wiring X is reduced, so that the charges accumulated in the scanning line 1 can be safely diffused. Accordingly, electrostatic breakdown of the scanning line 1 can be reliably prevented. Further, the common wiring is not directly connected to the driving circuit elements and the TFTs on the array substrate. Therefore, even if the protection capacitance line X is connected to this wiring, it does not affect the circuit operation of the array substrate.

The above-described embodiment is merely an example, and does not limit the present invention. For example, in the above embodiment, both ends of the line X constituting the protection capacitance are connected to the common wiring. However, as long as the wiring pattern is not limited to the common wiring and has a relatively large area on the switching element array substrate and does not interfere with the circuit operation of the array substrate, the same applies to the case where the wiring pattern is connected to another power supply wiring. Effects can be obtained.

In the above embodiment, the scanning line 1 is the object to be protected, and the first line is provided near the scanning line 1 as a protection capacitance.
The electrode Cm and the second electrode X1 are arranged to face each other via an insulating film. However, the object to be protected can be another wiring such as a signal line or an auxiliary capacitance line, or the vicinity of a TFT as a switching element. In this case, the protection capacitance as described in the above embodiment may be arranged near the protection target. In the above embodiment shown in FIG.
The first electrode Cm and the second electrode X1 are located not only near the scanning line 1 but also near the auxiliary capacitance line 2. Therefore, it is possible to reliably diffuse not only the scanning line 1 but also the electric charge accumulated in the auxiliary capacitance line 2.

[0024]

As described above, according to the switching element array substrate and the liquid crystal display device of the present invention, the switching element array substrate and the liquid crystal display device are arranged near at least one of the scanning line, the signal line, the switching element, and the auxiliary capacitance line. The protection capacitance line connected to one electrode of the protection capacitance is electrically connected to one of the wirings on the insulating substrate that does not interfere with the circuit operation. Is large, the change in potential is small even when the charge accumulated in the scanning line or the like diffuses into the protective capacitance, and the electrostatic breakdown of the scanning line or the like can be reliably prevented.

[Brief description of the drawings]

FIG. 1 is a plan view showing a configuration of a switching element array substrate used in a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a plan view showing a configuration of a switching element array substrate used in a conventional liquid crystal display device.

[Explanation of symbols]

 Reference Signs List 1 scanning line 1m molybdenum tungsten wiring (scanning line) 1a aluminum wiring (scanning line) 1c, 2c contact hole 2 auxiliary capacitance line 10 insulating substrate 2m molybdenum tungsten wiring (auxiliary capacitance line) 2a aluminum wiring (auxiliary capacitance line) Cm, X1 First electrode X1 Second electrode X Protection capacitance line 21 TFT 22 Pixel electrode 23 Signal line 24 Signal line drive circuit 25 Scan line drive circuit 26 Common wiring

Claims (5)

[Claims] An insulating substrate; a plurality of rows of scanning lines and a plurality of columns of signal lines arranged to intersect with each other on the insulating substrate; and the scanning lines and the signal lines on the insulating substrate. A plurality of pixel electrodes arranged in the vicinity of the intersection of and a liquid crystal pixel consisting of a common electrode opposed to the pixel electrode via a liquid crystal layer, and on the insulating substrate, arranged for each of the pixel electrodes,
A switching element connected to the scanning line, the signal line, and the pixel electrode; a scanning line driving circuit formed on the insulating substrate to drive the scanning line; and a scanning line between adjacent scanning lines. A plurality of protection capacitance electrodes arranged electrically insulated; a protection capacitance wiring disposed opposite to the plurality of protection capacitance electrodes via an interlayer insulating film; A liquid crystal display device, comprising: a power supply wiring connected to the wiring. 2. The liquid crystal display device according to claim 1, wherein said protection capacitance electrodes are arranged in a direction substantially orthogonal to a direction in which said scanning lines extend. 3. The liquid crystal display device according to claim 1, wherein said protective capacitance electrode is formed in the same layer as said scanning line. 4. The liquid crystal according to claim 1, wherein said protection capacitance electrode is formed between an effective display area where said liquid crystal pixels are arranged and said scanning line drive circuit formation area. Display device. 5. The liquid crystal display device according to claim 1, wherein said power supply line is a power supply line for supplying a voltage to said common electrode.