KR100920346B1 - Thin film transistor array panel and liquid crystal display including the panel - Google Patents

Abstract

The liquid crystal display of the present invention includes a plurality of pixels arranged in a matrix form, a plurality of gate lines and data lines for transmitting signals to the pixels, a gray voltage generator for generating a plurality of gray voltages, and image data among the plurality of gray voltages. A data driver which selects a corresponding gray voltage and outputs the data voltage as a data voltage, an odd-numbered switching element connected to an odd-numbered data line and an even-numbered switching element connected to an even-numbered data line, and a transmission gate part connected to the data driver. A first conductive layer and an impurity that are connected to the data driver and the transmission gate part to generate a control signal for controlling the image data and to apply the image data to the data driver; Resistor in which the second conductive layer made of this doped silicon is in contact It includes having an electrostatic protection unit. The static electricity flowing through the high contact resistance of the resistor unit is induced to discharge the discharge unit, thereby preventing the driving element from being damaged.

LCD, LCD, Static electricity, Discharge, Resistance

Description

Thin film transistor array panel and liquid crystal display including the same {THIN FILM TRANSISTOR ARRAY PANEL AND LIQUID CRYSTAL DISPLAY INCLUDING THE PANEL}

1 is a configuration diagram of a liquid crystal display according to an exemplary embodiment of the present invention.

2 is an equivalent circuit diagram of one pixel of a liquid crystal display according to an exemplary embodiment of the present invention.

3 is a cross-sectional view illustrating in detail a structure of an electrostatic protection unit in a liquid crystal display according to an exemplary embodiment of the present invention.

4 is a plan view illustrating in detail the structure of the resistor unit in the electrostatic protection unit of FIG. 3;

FIG. 5 is a cross-sectional view taken along the line VV ′ of FIG. 4.

The present invention relates to a thin film transistor array panel and a liquid crystal display device including the same.

A typical liquid crystal display (LCD) includes two display panels including a pixel electrode and a common electrode, and a liquid crystal layer interposed therebetween and having dielectric anisotropy. A voltage is applied to both electrodes to generate an electric field in the liquid crystal layer, and the intensity of the electric field is adjusted to adjust the transmittance of light passing through the liquid crystal layer to obtain a desired image. The pixel electrodes are arranged in a matrix and connected to switching elements such as thin film transistors (TFTs) to receive data voltages one by one in sequence. The common electrode is formed on the entire surface and receives a common voltage.

One of the two display panels includes a plurality of wirings such as a gate line and a data line, a thin film transistor for controlling a data signal transmitted to the pixel electrode and the pixel electrode (hereinafter referred to as a thin film transistor display panel), and the other display panel includes a pixel electrode and It is common that the common electrode facing and the color filter of red (R), green (G), and blue (B) are formed (henceforth opposing display panel).

In this case, the thin film transistor array panel is easily exposed to static electricity generated during the manufacturing process, which causes the destruction of devices formed on the display panel and the deterioration of electrical characteristics of the devices. In particular, it is essential to protect the driving circuit or the thin film transistor from static electricity when the driving circuit is integrated into the display panel at the same time as the thin film transistor is formed using polysilicon as the semiconductor of the thin film transistor.

SUMMARY OF THE INVENTION The present invention provides a thin film transistor array panel and a liquid crystal display device capable of protecting a driving circuit or a thin film transistor from static electricity.

As an aspect of the present invention, an electrostatic protection unit electrically connected to a driving element or a thin film transistor includes a contact portion in contact with a metal layer and a silicon layer.

More specifically, the thin film transistor array panel according to the exemplary embodiment of the present invention may be connected to a driving element or a display signal line, and the other end of the thin film transistor array panel may be configured to include a first conductive layer made of silicon and a first conductive layer. A resistance portion including a second conductive layer made of a metal, a second conductive layer made of a metal, and a third conductive layer made of a metal, and a discharge portion connected to the second or third conductive layer, respectively, connected to both ends. .

It is preferable that the discharge portion has a diode, and the first conductive layer is doped with impurities.

The liquid crystal display according to the exemplary embodiment may include a plurality of pixels arranged in a matrix form, a plurality of gate lines and data lines for transmitting signals to the pixels, and a gray voltage generator for generating a plurality of gray voltages. A data driver which selects a gray voltage corresponding to the image data among the gray voltages and outputs it as a data voltage, and includes an odd-numbered switching element connected to the odd-numbered data line and an even-numbered switching element connected to the even-numbered data line. A transmission gate part connected to the data driver, a signal control part for inputting image data to the data driver and generating a control signal for controlling the image data and applying the data signal to the data driver and the transmission gate part, and connected to the transmission gate part. The first conductive layer made of metal and the second conductive layer made of metal are in contact with each other. It includes parts having electrostatic protection resistor portion.

The static electricity protection unit has a discharge unit for discharging static electricity flowing into the static electricity protection unit, and the discharge unit preferably has a diode, and the first conductive layer is preferably doped with impurities.

DETAILED DESCRIPTION Embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like parts are designated by like reference numerals throughout the specification. When a portion of a layer, film, region, plate, etc. is said to be "on top" of another part, this includes not only when the other part is "right on" but also another part in the middle. On the contrary, when a part is "just above" another part, there is no other part in the middle.

Now, a thin film transistor array panel and a liquid crystal display including the same according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

An embodiment of the present invention will be described with reference to a structure in which an electrostatic protection circuit is connected to a transfer gate type liquid crystal display and a transfer gate.

First, a structure of a liquid crystal display according to an exemplary embodiment of the present invention will be described with reference to FIGS. 1 and 2.                     

1 is a conceptual diagram of a liquid crystal display according to an embodiment of the present invention, FIG. 2 is an equivalent circuit diagram of one pixel of the liquid crystal display according to an embodiment of the present invention, and FIG. 3 is an embodiment of the present invention. In the liquid crystal display according to the present invention, a cross-sectional view showing a structure of an electrostatic protection unit in detail.

As shown in FIGS. 1 and 2, the liquid crystal display according to the present invention is a transmission gate type liquid crystal display device, and includes a liquid crystal panel assembly 300 and a gate driver connected thereto. 400, the transmission gate unit 750, the data driver 500 connected to the transmission gate unit 750, the gray voltage generator 800 connected to the data driver 500, and a signal controller 600 and a signal controller to control them. And a static electricity protection unit 900 connected to the 600 and the transmission gate unit 750.

The liquid crystal panel assembly 300 includes a plurality of display signal lines G ₁ -G _n , D ₁ -D _2l and a plurality of pixels P and pixels connected to the plurality of display signal lines G ₁ -G _n , D ₁ -D _2l , and arranged in a substantially matrix form. Include.

The display signal lines G ₁ -G _n and D ₁ -D _2l are a plurality of gate lines G ₁ -G _n and gate lines G ₁ -G _n that transmit a gate signal (also called a “scan signal”). And a data line D ₁ -D _2l that intersects and transmits the data signal. The gate lines G ₁ -G _n extend substantially in the row direction and are substantially parallel to each other, and the data lines D ₁ -D _2l extend substantially in the column direction and are substantially parallel to each other.

Each pixel includes a switching element TFT connected to a display signal line G ₁ -G _n , D ₁ -D _2l , a liquid crystal capacitor C _lc , and a storage capacitor C _st connected thereto. It includes. The holding capacitor C _st can be omitted as necessary.

The switching element TFT is provided in the thin film transistor array panel 100, and the control terminal and the input terminal thereof are connected to the gate line G ₁ -G _n and the data line D ₁ -D _2l, respectively. The output terminal is connected to the liquid crystal capacitor C _lc and the storage capacitor C _st .

The liquid crystal capacitor C _lc uses the pixel electrode 190 of the thin film transistor array panel 100 and the common electrode 270 of the opposing display panel 200 as two terminals, and the liquid crystal layer 3 between the two electrodes 190 and 270. Functions as a dielectric. The pixel electrode 190 is connected to the switching element TFT, and the common electrode 270 is formed on the front surface of the opposing display panel 200 and receives the common voltage V _com . Unlike in FIG. 2, the common electrode 270 may be provided in the thin film transistor array panel 100. In this case, both electrodes 190 and 270 may be linear or rod-shaped.

The storage capacitor C _st is formed by overlapping a separate signal line (not shown) and the pixel electrode 190 included in the thin film transistor array panel 100, and a predetermined voltage such as a common voltage V _com is provided on the separate signal line. Is applied. However, the storage capacitor C _st may be formed such that the pixel electrode 190 overlaps the front gate line directly above the insulator.

Meanwhile, in order to implement color display, each pixel must display color, which is possible by providing a red, green, or blue color filter 230 in a region corresponding to the pixel electrode 190. In FIG. 2, the color filter 230 is formed in a corresponding region of the opposing display panel 200. Alternatively, the color filter 230 may be formed above or below the pixel electrode 190 of the thin film transistor array panel 100.

The liquid crystal molecules change their arrangement according to the electric field generated by the pixel electrode 190 and the common electrode 270, and thus the polarization of light passing through the liquid crystal layer 3 changes. The change in polarization is represented by a change in transmittance of light by a polarizer (not shown) attached to the display panels 100 and 200.

The gray voltage generator 800 generates a plurality of gray voltages V + and V− of the positive (+) and the negative (-) related to the luminance of the liquid crystal display.

The gate driver 400 is connected to the gate lines G ₁ -G _n of the liquid crystal panel assembly 300 to receive a gate signal formed by a combination of a gate on voltage V _on and a gate off voltage V _off from the outside. It is applied to the gate lines G ₁ -G _n .

The data driver 500 is connected to the transfer gate unit 750 and selects the gray voltages V + and V− from the gray voltage generator 800 and applies them to the transfer gate unit 750 as data signals. The data driver 500 includes a shift register (not shown), a digital-to-analog (D / A) converter (not shown), an output buffer (not shown), and the like that are sequentially connected. In this case, the shift register and the output buffer are connected to the signal controller, and the D / A converter is connected to the gray voltage generator.

The transfer gate portion 750 includes the same number of transistors T ₁ -T _2l as the number of data lines D ₁ -D _2l of the assembly 300, with each transistor T ₁ -T _2l being a data driver. And an input terminal connected to 500 and an output terminal connected to a corresponding data line D ₁ -D _2l .

Even number of odd _- numbered transistors (T ₁ , T ₃ , ..., T _2l-1 ) with output terminals connected to odd _- numbered data lines (D ₁ , D ₃ , D ₅ , ... D _2l-1 ) Input terminals of even-numbered transistors (T ₂ , T ₄ , ..., T _2l ) having output terminals connected to the second data line (D ₂ , D ₄ , D ₆ , ... D _2l ) are paired. The control terminals of the odd _- numbered transistors T ₁ , T ₃ , ..., T _2l-1 and the control terminals of the even-numbered transistors T ₂ , T ₄ , ..., T _2l are connected to each other. Other signals, for example, signals that are inverted from each other, are applied.

In this embodiment, each transistor T ₁ -T _2l is an N-type MOS transistor, but may also be a P-type MOS transistor.

The signal controller 600 generates a control signal for controlling operations of the gate driver 400, the data driver 500, the transmission gate part 750, and the like, and outputs corresponding control signals to the gate driver 400 and the data driver. And a transmission gate unit 750.

The display operation of such a liquid crystal display device will now be described in detail.

The signal controller 600 inputs an input control signal for controlling the RGB image signals R, G, and B and their display from an external graphic controller (not shown), for example, a vertical sync signal V _sync and a horizontal sync signal. (H _sync ), a main clock (MCLK), a data enable signal (DE) is provided. The signal controller 600 generates a gate control signal CONT1, a data control signal CONT2, a pair of data selection signals TG1 and TG2, a common voltage V _com , and the like based on the input control signal, and generates an image signal. After appropriately processing (R, G, B) in accordance with the operating conditions of the liquid crystal panel assembly 300, the gate control signal CONT1 is sent to the gate driver 400, and the data control signal CONT2 and the processed image signal ( R ', G', and B 'are sent to the data driver 500, the data select signals TG1 and TF2 are sent to the transfer gate 750, and the common voltage V _com is sent to the assembly 300. .

The gate control signal CONT1 includes a vertical synchronization start signal STV indicating the start of output of the gate on pulse (gate on voltage section), a gate clock signal CPV for controlling the output timing of the gate on pulse, and a gate on pulse. An output enable signal OE or the like that defines a width.

The data control signal CONT2 is a load for applying a corresponding data voltage to the horizontal synchronization start signal STH indicating the start of input of the image data R ', G', and B 'and the data lines D ₁ -D _2l . Signal LOAD, inverted signal RVS and data that inverts the polarity of the data voltage with respect to common voltage V _com (hereinafter referred to as " polarity of data voltage " by reducing " polarity of data voltage with respect to common voltage "). Clock signal HCLK and the like.

The common voltage V _com generated by the signal controller 600 is converted to a predetermined voltage level through a level shifter (not shown) and then supplied to the assembly 300. According to another exemplary embodiment of the present invention, the signal controller 600 does not generate the common voltage V _com , and in a separate common voltage generator (not shown), the inverted signal RVS from the signal controller 600, or the like. The common voltage V _com is generated based on this.

The data driver 500 sequentially receives the image data of the odd-numbered pixels and the image data of the even-numbered pixels from the signal controller 600 according to the data control signal CONT2, and converts the image data as analog data.

The gate driver 400 applies the gate-on voltage V _on to the gate lines G ₁ -G _n in response to the gate control signal CONT1 from the signal controller 600, thereby applying the gate lines G ₁ -G _n. Turn on the switching element (TFT) connected to.

The gate-on voltage V _on is applied to one gate line G ₁ -G _n so that a row of switching elements TFT connected thereto is turned on (this period is "1H" or "1 horizontal period). (horizontal period) "and equal to one period of the horizontal sync signal Hsync, the data enable signal DE, and the gate clock CPV], and the signal controller 600 generates a pair of data selection signals TG1. , The signal state of DS1 applied to the odd-numbered transistors (T ₁ , T ₃ , ..., T _2l-1 ) among the TG2 is set to high level and the even-numbered transistors (T ₂ , T ₄ , ..., T _2l When the state of DS2 applied to the low level is set, only the odd-numbered transistors T ₁ , T ₃ , ..., T _2l-1 are turned on, and the odd-numbered data lines D ₁ , D ₃ , ..., The corresponding data signal is supplied to D _2l-1 ). Thereafter, the signal state of the DS1 to the low level odd-numbered transistors _{(T 1, T 3, ...} , T 2l-1) was turned off, and at the same time and a signal state DS2 at a high level. Then, as described above, the corresponding data signal is supplied to the even-numbered data lines D ₂ , D ₄ , ..., D _2l connected to the even-numbered transistors T ₂ , T ₄ , ..., T _2l .

The data signals supplied to the data lines D ₁ -D _2l are applied to the corresponding pixels through the turned-on switching element TFT.

As a result, the data signal is alternately supplied to the odd-numbered and even-numbered pixels during one horizontal period, and a common voltage V _com having a different magnitude is applied to the odd-numbered and even-numbered pixels.

In this way, the gate-on voltage V _on is sequentially applied to all the gate lines G ₁ -G _n during one frame to apply the data signal to all the pixels.

When manufacturing the thin film transistor array panel 100 in such a liquid crystal display, when the semiconductor of the switching element TFT is formed using polycrystalline silicon, the switching element TFT is formed in the thin film transistor array panel 100 using the semiconductor. In addition, driving elements such as the data driver 500 or the gate driver 400 are also formed. In this case, in order to prevent the static electricity generated during the manufacturing process from flowing into a driving element such as the data driver 500 or the gate driver 400, they include an electrostatic protection circuit, and an odd number is also present at the front end of the transmission gate part 750. Electrostatic protection unit 900 to prevent the first transistor (T ₁ , T ₃ , ..., T _2l-1 ) and even _- numbered transistors (T ₂ , T ₄ , ..., T _2l ) from being damaged from static electricity. ) Is connected, and as shown in FIG. 3, the static electricity protection unit 900 includes a resistor unit 910 and a discharge unit 920. In this case, the discharge unit has a function of discharging when static electricity including an electrostatic diode (not shown) is introduced, and when the data selection signals TG1 and TF2 are transmitted from the outside, the discharge unit is transferred to the transmission gate unit 750, and the static electricity is transmitted. When is introduced to have a function to bypass the static electricity to the discharge portion.

Next, the electrostatic protection unit will be described in detail with reference to the accompanying drawings.

FIG. 4 is a plan view of a thin film transistor array panel specifically illustrating a structure of a resistor in the electrostatic protection unit of FIG. 3, and FIG. 5 is a cross-sectional view taken along the line VV ′ of FIG. 4.

4 and 5, in the thin film transistor array panel according to the exemplary embodiment of the present invention, data selection signal lines 901 and 902 for transmitting data selection signals TG1 and TF2 to the insulating substrate 110. These are formed, respectively. In the drawing, the B direction is a direction electrically connected to the driving element or the display signal line G ₁ -G _n , D ₁ -D _2l , such as the transmission gate part 750 (see FIG. 1) or the switching element TFT. The A direction is a direction in which the data selection signals TG1 and TG2 are transmitted from the outside.
Each of the data selection signal lines 901 and 902 has the same structure and is connected to both ends of the first conductive layer 913 and the first conductive layer 913 formed on the insulating substrate 110. A third conductive layer 911 is connected to the second conductive layer 912 and the second conductive layer 912, respectively. The first conductive layer 913 and the second conductive layer 912 are connected to each other through first contact holes 803 formed in the first and second insulating layers 140 and 180 covering the first conductive layer 913. The second conductive layer 912 and the third conductive layer 911 are connected to each other through a second contact hole 801 formed in the second insulating layer. In this case, the first conductive layer 913 is made of polycrystalline silicon doped with n-type or p-type impurities, and the second conductive layer 912 and the third conductive layer 911 are made of aluminum, aluminum alloy, or chromium. It consists of low-resistance metal materials, such as molybdenum. Therefore, the contact resistance in the first contact hole 803, which is a contact portion where the second conductive layer 912 made of the metal material and the first conductive layer 913 made of the doped polycrystalline silicon, is in contact with each other, is a contact portion in contact with the metal materials. Is greater than the contact resistance. Accordingly, when static electricity is generated from the outside during the manufacturing process of the thin film transistor array panel, static electricity flows through the first and second data selection signal lines 901 and 902 in the A direction. Since the contact resistance in the first contact hole 803, which is the contact portion that the layer 913 contacts, is large, the static electricity is diverted to the discharge portion 920, and the static electricity is discharged in the discharge portion 920.

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In this case, positions of the second conductive layer 912 and the third conductive layer 911 may be changed from each other, and the contact structure may also be changed.

In addition, the electrostatic protection unit including the resistor unit 910 may be connected to the front and rear ends of the display signal lines G ₁ -G _n and D ₁ -D _2l .

In the thin film transistor array panel and the liquid crystal display, the resistance unit may be manufactured in various modified forms and methods.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

As such, by disposing an electrostatic protection unit having a resistor in contact with the metal layer and the silicon layer in front of the driving element or the signal line, it is possible to effectively discharge the static electricity, thereby effectively preventing the driving element or the thin film transistor of the driving circuit unit from being damaged. Can be.

Claims (7)

A plurality of pixels arranged in a matrix form, A plurality of gate lines and data lines for transmitting signals to the pixels; A gray voltage generator for generating a plurality of gray voltages; A data driver which selects a gray voltage corresponding to image data among the plurality of gray voltages and outputs the gray voltage corresponding to the image data; A transmission gate part including an odd number switching element connected to an odd data line and an even number switching element connected to an even data line and connected to the data driver; A signal controller which inputs image data to the data driver, generates a control signal for controlling the image data, and applies the image data to the data driver and the transmission gate; An electrostatic protection portion connected to the transfer gate portion and having a resistance portion in which a first conductive layer made of silicon and a second conductive layer made of metal are in contact with each other; Liquid crystal display comprising a. In claim 1, The electrostatic protection unit includes a discharge unit for discharging the static electricity flowing into the electrostatic protection unit. In claim 2, And the discharge portion has a diode. In claim 1, And the first conductive layer is doped with an impurity. One end is connected to a driving element or a display signal line, and the other end is a signal transmitted from the outside, and is connected to both ends of the first conductive layer made of silicon and the second conductive layer made of metal. A resistance part connected to each of the two conductive layers and including a third conductive layer made of a metal, A discharge part connected to the second or third conductive layer Thin film transistor array panel comprising a. In claim 5, The thin film transistor array panel of which the discharge unit has a diode. In claim 5, The first conductive layer is a thin film transistor array panel doped with an impurity.

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