JP3241981B2 - Liquid crystal display - Google Patents

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 a liquid crystal display device during a manufacturing process other than the original display operation. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device in which an active element is formed to prevent charges from being stored between electrode lines.

[0002]

2. Description of the Related Art In this type of matrix wiring board, a lower wiring and an upper 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 line formed with the insulating film and the semiconductor film interposed therebetween as both electrodes. The accumulated charges change characteristics of a semiconductor or the like, and may affect display of picture elements. Conventionally,
In order to prevent such a change in characteristics, the electrode lines formed in a matrix are grouped into a plurality of lines,
In some cases, an electrode wire (short ring) is formed so as to be electrically conductive.

[0003]

In the above-mentioned prior art, the electrode lines in which a plurality of electrode lines formed in a matrix of a liquid crystal display device are integrated are formed during the manufacturing process, for example, between the matrix-shaped electrode lines. Must be cut off when measuring the resistance of each pixel and checking the driving state of each picture element in the original display state of the liquid crystal display device. Also, in this manufacturing process in which the electrode lines formed by combining the electrode lines formed in a matrix into a plurality of lines and a voltage or an electric signal must be applied to the electrode lines, other electrode lines are required. In many cases, charges are stored between the matrix-shaped electrode lines as compared with the manufacturing process of forming the like. The present invention has been made in view of such circumstances, and means for preventing charge from being accumulated between the matrix electrode lines in all of the manufacturing processes of a liquid crystal display device, and even when not in use after commercialization. It is an object of the present invention to provide a structured liquid crystal display device.

[0004]

According to a first aspect of the present invention, there are provided a plurality of display driving thin film transistors (TFTs) on an insulating substrate such as glass or quartz, and a plurality of scanning electrodes for operating the display driving TFTs. A first substrate in which a plurality of data signal electrode lines for giving data to the pixels and the pixel electrodes connected to the respective display driving TFTs are arranged in a matrix, and a transparent electrode on an insulating substrate such as glass or quartz. In an 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 substrate and the second substrate, a final TFT connected to a final electrode of an electrode on the substrate is connected to the display driving TFT. In addition to forming the TFTs separately from the TFTs, the final TFTs form a common final TFT driving terminal so that signals can be externally supplied to all of them, and the final TFTs are also formed. One of the data receiving terminal is a terminal, the data receiving terminal of all final end TFT becomes electrically conductive, and electrodes are formed line to serve as a final end TFT short ring, the outermost
By applying a negative voltage to the terminal TFT drive terminal
The resistance value of the terminal TFT is increased, and the electric charge stored between the electrodes is released to the terminal TFT short ring, thereby preventing the occurrence of defective display characteristics of picture elements due to the accumulation of the electric charge.

According to a second aspect of the present invention, the last TFT is formed only at the last end of the data signal electrode line so that electric charges of only the input signal electrode line of each picture element are released, and the electric charge is stored in the picture element by charge accumulation. The final TFT is formed only on the electrode lines which are likely to have an influence.

According to a third aspect of the present invention, in the first aspect of the present invention, the final TFT is formed on the electrode lines formed in a matrix on the first substrate, and the final TFT driving terminal is formed.
The electric charge stored between the electrode lines is released without applying a voltage to the electrodes.

According to a fourth aspect of the present invention, in the first or the third aspect of the present invention, the final end is provided on the electrode lines formed in a matrix on the first substrate and on the transparent electrodes formed on the second substrate. A TFT is formed so that electric charges stored between the electrode line and the transparent electrode are released.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view of a main portion of a liquid crystal display device according to an embodiment 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 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 terminal TFT 107 and a terminal 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 configuration of the data signal electrode line terminal 105, a final TFT driving terminal 109 which is a driving terminal of the final TFT 107 is formed.

The final TFT 107 has a resistance value between the scan electrode line 104 and the data signal electrode line 106 and the final TFT short ring 108 connecting them, according to the voltage of the drive signal input to the final TFT drive terminal 109. Act to change. FIG.
5 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, it is in a state before the start of the ON operation shown in FIG. In the state after the end of the display operation, the voltage input to the terminal TFT driving terminal 109 is 0 V, no voltage is applied, and the resistance value of the terminal TFT becomes small.

On the other hand, when the liquid crystal display device is in a display state, it is input to the terminal TFT drive terminal 109 from the start of the display operation at the ON timing to the end of the display operation at the OFF timing shown in FIG. The voltage is, for example,
At -10 V, a negative voltage is applied,
The resistance value of the last TFT 107 increases. Terminal TF
In T107, the resistance value is changed by the final-end TFT drive signal shown in FIG. 2 to release charges or affect display between the scan electrode line 104 and the data signal electrode line 106 via the final-end TFT short ring 108. And make sure they don't come out. The resistance value of the final TFT 107 is, for example, several tens to several hundreds MΩ when the final TFT driving voltage is 0 V, and several tens to several hundreds GΩ when the final voltage is negative. If necessary, adjust the final TFT so that the overall resistance value is several tens to several hundredths.
107 is formed.

Another embodiment of the present invention will be described below. One is to form a final TFT only on a data signal electrode line which easily affects a picture element due to charge accumulation. The other is to form a final TFT 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 to form a TFT between the electrode line and the counter transparent electrode. The stored charge is also released. In addition, in implementing the present invention, it is possible to more effectively prevent the charge accumulation by using it in combination with the conventional short ring.

[0012]

According to the present invention, the final TFT is formed at the end of the electrode on the substrate, and no voltage is applied to the final TFT drive terminal (0 V). Since the structure is such that the charge is released, the charge is always released during the manufacturing process in a state other than the original display operation, or during non-use such as storage or transportation after commercialization. There is no accumulation of charges that change the characteristics and affect the display of picture elements. The voltage is applied to the final TFT only when the liquid crystal display device is used, and only the negative potential is applied. Therefore, 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 of a liquid crystal display device according to an embodiment of the present invention, a part of which is shown as an enlarged view.

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

[Explanation of symbols]

101: liquid crystal display device, 102: display portion of the liquid crystal display device, 103: scanning electrode line terminal, 104: scanning electrode line, 1
05: Data signal electrode line terminal, 106: Data signal electrode line, 107: Final TFT, 108: Final TFT short ring, 109: Final TFT drive terminal.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-10558 (JP, A) JP-A-6-317810 (JP, A) JP-A-6-51347 (JP, A) JP-A-6-51347 27490 (JP, A) JP-A-6-186592 (JP, A) JP-A-5-333377 (JP, A) JP-A-11-202289 (JP, A) JP-A 9-152620 (JP, A) JP-A-9-127545 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/136 G02F 1/1343

Claims (4)

(57) [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 giving 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 an active matrix type liquid crystal display device having a structure having an alignment film layer and a liquid crystal layer in a gap between the display driving TFT and the last TFT connected to the last end of an electrode on the substrate,
In addition to the above, the final TFT is formed with a common final TFT drive terminal so that signals can be externally supplied to all of them. receiving terminal, said data receive terminal of all final end TFT becomes electrically conductive, and electrodes are formed line to serve as a final end TFT short ring, the final end TFT driving end
By applying a negative voltage to the element,
A charge accumulated between the electrodes is released to a TFT short ring at the final end to prevent the occurrence of a defective display characteristic of a picture element due to charge accumulation. 2. The liquid crystal device according to claim 1, wherein said TFT is formed only at the last end of said data signal electrode line, so that electric charges of only each input signal electrode line of each picture element are released. Display device. Wherein forming the final end TFT to the first electrode lines formed in a matrix on a substrate, the final end T
2. The liquid crystal display device according to claim 1 , wherein electric charges stored between the electrode lines are released while no voltage is applied to the FT drive terminal . 4. The final TFT is formed on an electrode line formed in a matrix on the first substrate and on a transparent electrode formed on the second substrate, and between the electrode line and the transparent electrode. 4. The liquid crystal display device according to claim 1, wherein the electric charges stored in the liquid crystal display are released.