JPH09160073A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device capable of preventing the accumulation of electrostatic charge among the matrix electrode lines in the manufacturing process of the device or when the manufactured device is not used. SOLUTION: Plural displaying thin film transistors(TFTs) formed on an insulating substrate, scanning electrode lines 104 for the TFTs and data electrode lines 106 for pixel electrodes are arrayed on a 1st substrate like a matrix. The active matrix type liquid crystal display device is constituted of an orientation film layer and a liquid crystal layer formed in a gap between the 1st substrate and a 2nd substrate provided with a transparent electrode set on the insulating substrate. In this case, a final end TFT driving terminal 109 common to final end TFTs 107 connected to an electrode ends on the substrate is formed and a signal is applied from the outside to the terminal 109. The other data receiving terminal of each final end TFT 107 forms an electrode line as a final end TFT short ring 108 so as to be turned to a completely conductive state. Thereby the final end TFT driving terminal 109 is driven to change the resistance values of the TFTs, charge among the electrodes is leaked to the final end TFT short rings 108 to prevent the generation of defective display characteristics of pixels due to the accumulation of charge.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix type liquid crystal display device, and more particularly, to a change in display characteristics of picture elements in the liquid crystal display device other than the original display operation, for example, during the manufacturing process. The present invention relates to a liquid crystal display device in which active elements are formed in order to prevent charges from being accumulated between electrode lines.

[0002]

2. Description of the Related Art In this type of matrix wiring substrate, a lower layer wiring and an upper layer wiring are laminated on a glass substrate via an insulating film or an insulating film and a semiconductor film. Therefore, in a manufacturing process or the like, electric charges may be accumulated as a capacitor having the electrode lines formed by sandwiching the insulating film and the semiconductor film as the two electrodes. The accumulated charges may change the characteristics of the semiconductor or the like and affect the display of picture elements. Conventionally,
In order to prevent such changes in characteristics, the electrode lines formed in a matrix are grouped into a plurality of
There is a type in which an electrode wire (short ring) that forms an electrically conductive state is formed.

[0003]

In the above-mentioned conventional technique, an electrode line in which a plurality of electrode lines formed in a matrix of a liquid crystal display device are collected is formed during the manufacturing process, for example, between the matrix-shaped electrode lines. It becomes necessary to disconnect when measuring the resistance and checking the driving state of each picture element in the original display state of the liquid crystal display device. In addition, in this manufacturing process, in which a plurality of electrode wires formed in a matrix form are cut and the voltage or electric signal is applied to the electrode wires, Electric charges are often stored between the matrix-shaped electrode lines as compared with the manufacturing process for forming the same. The present invention has been made in view of the above circumstances, and provides means for preventing electric charges from being accumulated between matrix electrode lines in all manufacturing steps of a liquid crystal display device and also when the liquid crystal display device is not used after being commercialized. It is an object to be solved to provide a liquid crystal display device having a structure.

[0004]

According to a first aspect of the present invention, a plurality of display driving thin film transistors (TFTs) are provided on an insulating substrate such as glass or quartz, and a plurality of scanning electrodes for operating the display driving TFTs. Line and a first substrate on which a plurality of data signal electrode lines for supplying data to pixel electrodes connected to the display driving TFT are arranged in a matrix, and a transparent electrode on an insulating substrate such as glass or quartz. In the active matrix liquid crystal display device having a structure in which an alignment film layer and a liquid crystal layer are provided in the gap between the second substrate provided with the liquid crystal display device, a final-end TFT connected to the final end of an electrode on the substrate is used for the display drive. The TFTs are formed separately from the TFTs, and the final-end TFTs form a common final-end TFT drive terminal so that a signal can be externally applied to all of them. The data receiving terminal, which is one terminal, is formed by forming an electrode line so that the data receiving terminals of all the final end TFTs are electrically conductive and functioning as a final end TFT short ring. By operating the end TFT drive terminal, the TFT
The resistance value is changed so that the electric charge accumulated between the electrodes is released to the final end TFT short ring to prevent the display characteristic defect of the picture element due to the electric charge accumulation.

According to a second aspect of the present invention, the final end TFT is formed only at the final end of the data signal electrode line so that the electric charge to only the input signal electrode line of each picture element is released and the electric charge is accumulated in the picture element. The final-end TFT is formed only on the electrode line that is likely to have an influence.

According to a third aspect of the present invention, in the first aspect of the invention, the final end TFT is formed on the electrode line formed in a matrix on the first substrate, and the charge accumulated between the electrode lines is released. To do so.

According to a fourth aspect of the present invention, in the first or third aspect of the invention, the electrode lines formed in a matrix on the first substrate and the transparent electrode formed on the second substrate have the final end. The TFT is formed so that the electric charge stored between the electrode line and the transparent electrode is also released.

[0008]

FIG. 1 is a schematic view of a main part in an embodiment of a liquid crystal display device of the present invention, and a part thereof is shown as an enlarged view. FIG. 1 shows an electrode configuration provided on one substrate of an active matrix type liquid crystal display device 101 having a display portion 102 between insulating substrates such as glass and quartz. The scanning electrode lines 104 and the data signal electrode lines 106 are arranged in a matrix, and have scanning electrode line terminals 103 and data signal electrode line terminals 105 at the ends of both electrode lines. Further, a final end TFT 107 and a final end TFT short ring 108 are provided on the side opposite to these terminal portions. Then, the scanning electrode line terminal 103
Similarly to the terminal structure of the data signal electrode line terminal 105, a final end TFT drive terminal 109 which is a drive terminal of the final end TFT 107 is formed.

The final-end TFT 107 has a resistance value between the scanning electrode line 104, the data signal electrode line 106, and the final-end TFT short ring 108 connecting them according to the voltage of the drive signal input to the final-end TFT drive terminal 109. Operates to change. FIG. 2 shows the final-end TFT 107.
It shows the state of the voltage of the drive signal applied to the.
When the liquid crystal display device 101 is in a state other than the original display operation, for example, during the manufacturing process, storage, or transportation, the liquid crystal display device 101 is in the state before the start of the display operation, which is the ON timing shown in FIG. 2, or the OFF timing. After the end of the display operation, the voltage input to the final-end TFT drive terminal 109 is 0 V, no voltage is applied, and the resistance value of the final-end TFT becomes small.

On the other hand, when the liquid crystal display device is in the display state, it is input to the final-end TFT drive terminal 109 from the start of the display operation having the ON timing shown in FIG. 2 to the end of the display operation having the OFF timing. The voltage is, for example,
At -10V, a negative voltage is applied,
The resistance value of the final-end TFT 107 increases. Last end TF
T107 changes the resistance value according to the final end TFT drive signal shown in FIG. 2 and releases the charge between the scanning electrode line 104 and the data signal electrode line 106 via the final end TFT short ring 108 and affects the display. To prevent it from appearing. The resistance value of the final-end TFT 107 is, for example, several tens to several hundreds MΩ when the final-end TFT drive voltage is 0V, and several tens to several hundreds GΩ when it is a negative voltage. If necessary, the final end TFT should have a resistance value of several tens to several hundreds.
Form 107.

Another embodiment of the present invention will be described below. One is that the final-end TFT is formed only on the data signal electrode line which tends to affect the picture element due to charge accumulation. The other is to form a final-end TFT also on a transparent electrode as a counter electrode of the above-mentioned electrode line provided on an insulating second substrate such as glass or quartz, and between the electrode line and the counter transparent electrode. The stored charge is also made to escape. Further, in the practice of the present invention, it is possible to more effectively prevent the accumulated charge by using it together with a short ring which is a conventional technique.

[0012]

According to the present invention, the final-end TFT is formed on the end portion of the electrode on the substrate, and the final-end TFT drive terminal is stored in the electrode such as an electrode wire in a state where no voltage is applied (0 V). Since it has a structure that allows electric charges to escape, it is always in a state where electric charges are released during the manufacturing process that is in a state other than the original display operation, or when it is not used during storage or transportation after commercialization. Charges that change the characteristics and affect the display of picture elements are not accumulated. The voltage is applied to the last-end TFT only when the liquid crystal display device is used, and since only a negative potential is applied, the circuit used in the current liquid crystal display device is changed. Is easy.

[Brief description of the drawings]

FIG. 1 is a schematic view of a main part in an embodiment of a liquid crystal display device of the present invention, a part of which is shown as an enlarged view.

FIG. 2 is a diagram showing a state of a drive signal input to a final-end TFT of the present invention.

[Explanation of symbols]

101 ... Liquid crystal display device, 102 ... Display part of liquid crystal display device, 103 ... Scan electrode line terminal, 104 ... Scan electrode line, 1
05 ... data signal electrode line terminal, 106 ... data signal electrode line, 107 ... final end TFT, 108 ... final end TFT short ring, 109 ... final end TFT drive terminal.

Claims (4)

[Claims] 1. A plurality of display driving thin film transistors (hereinafter referred to as “TFTs”) on an insulating substrate such as glass or quartz, a plurality of scanning electrode lines for operating the display driving TFTs, and the display driving TFTs. A first substrate in which a plurality of data signal electrode lines for providing data to the pixel electrodes connected to each are arranged in a matrix, and a second substrate in which a transparent electrode is provided on an insulating substrate such as glass or quartz. In the active matrix type liquid crystal display device having a structure in which an alignment film layer and a liquid crystal layer are provided in a gap between the display drive TFT and the final end TFT connected to the final end of the electrode on the substrate.
Separately from the above, the final-end TFTs form a common final-end TFT drive terminal so that a signal can be externally applied to all of them, and the final-end TFT data terminal is the other terminal. In the receiving terminal, the data receiving terminals of all the final end TFTs are electrically connected to each other, and an electrode line is formed so as to function as a final end TFT short ring, and the final end TFT drive terminals are operated. By changing the resistance value of the TFT, the electric charge accumulated between the electrodes is released to the final end TFT short ring to prevent the display characteristic defect of the picture element due to the electric charge accumulation. Display device. 2. The liquid crystal according to claim 1, wherein the final end TFT is formed only at the final end of the data signal electrode line so that the charge to only the input signal electrode line of each picture element is released. Display device. 3. The first end TFT is formed on an electrode line formed in a matrix on the first substrate so that charges accumulated between the electrode lines are released. Liquid crystal display device. 4. The final-end TFT is formed on the electrode lines formed in a matrix on the first substrate and the transparent electrodes formed on the second substrate, and between the electrode lines and the transparent electrodes. The liquid crystal display device according to claim 1 or 3, wherein charges stored in the liquid crystal display device are also released.