KR100505564B1 - Thin film transistor liquid crystal display and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a liquid crystal display device and a method of manufacturing the same, and more particularly, to a thin film transistor liquid crystal display device and a method of manufacturing the same that can reduce the parasitic capacitance of the bus lines and each node of the polysilicon TFT LCD driving circuit. . The driving circuit and the pixel are formed in the first substrate. The second substrate is disposed to face the first substrate, and a color filter and a transparent electrode designed to not overlap the region where the driving circuit is formed are formed.

Description

Thin film transistor liquid crystal display and a method of manufacturing the same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a method of manufacturing the same, and more particularly, to a thin film transistor liquid crystal display device capable of reducing parasitic capacitances of bus lines and respective electrical nodes of a polysilicon TFT LCD driving circuit. will be.

As multimedia applications of flat panel display devices increase, the necessity of high definition and high definition flat panel display devices is gradually increasing. A thin film transistor liquid crystal display (hereinafter referred to as "TFT LCD") is one of the spotlights as the flat panel display. Among the TFT LCDs, polysilicon TFT LCDs, which can incorporate a driving circuit, are attracting attention because they can lower the price and increase image quality by incorporating a driving circuit.

Increasing the number of pixels to drive high-quality TFT LCD should also improve the characteristics of the built-in polysilicon TFT driving circuit. To this end, signal delays of various bus lines must be small and load values of each electrical node must be small.

SUMMARY OF THE INVENTION An object of the present invention is to provide a thin film transistor liquid crystal display device capable of reducing parasitic capacitance of bus lines and respective electrical nodes of a polysilicon TFT LCD driving circuit.

Another object of the present invention is to provide a manufacturing method most suitable for manufacturing the device.

A thin film transistor liquid crystal display device according to the present invention for achieving the above object is disposed so as to face a first substrate on which a driving circuit and a pixel are formed, and the first substrate, and a color filter and a region in which the driving circuit is formed. And a second substrate on which a transparent electrode designed so as not to overlap with each other is formed.

A thin film transistor liquid crystal display device according to the present invention for achieving the above object is further disposed so as to face a first substrate on which a driving circuit and a pixel formed of a data driver and a gate driver are formed, and the first substrate, And a second substrate having a color filter and a transparent electrode formed so as not to partially overlap with any of the data driver and the gate driver.

In this case, the transparent electrode is designed such that only the bus line constituting each driver does not overlap with the bus line.

A method for manufacturing a thin film transistor liquid crystal display device according to the present invention for achieving the above another object is a portion overlapping a drive circuit formed on a second substrate after depositing a transparent electrode on a first substrate on which a color filter is formed. The process of removing the said transparent electrode is included.

According to another aspect of the present invention, there is provided a method of manufacturing a thin film transistor liquid crystal display device, further comprising: depositing a transparent electrode on a first substrate on which a color filter is formed; And partially removing the transparent electrode in a portion overlapping with a driving circuit composed of a gate driver.

In this case, the transparent electrode may be removed so as not to overlap only one of the data driver and the gate driver, or the transparent electrode may be removed so as not to overlap only the bus line among the bus lines and logic parts constituting each driver.

According to the present invention, since the transparent electrode is formed so as not to overlap with the driving circuit, the parasitic capacitance between the transparent electrode and the driving circuit can be reduced, thereby reducing the signal delay.

Hereinafter, a thin film transistor liquid crystal display and a method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings.

To help understand the present invention, a general TFT LCD will first be described before describing the present invention. In the drawings introduced subsequently, like reference numerals denote like parts.

1 is a schematic view showing a planar structure of a general polysilicon TFT LCD in which a driving circuit is incorporated, where reference numeral 10 denotes a pixel portion, numeral 12 denotes a data driver, and numeral 14 a gate driver. (gate driver), "16" represents a pad array, "100" represents an upper substrate, and "200" represents a lower substrate.

Although not shown, a color filter and a transparent electrode are formed on the upper substrate 100, and although not shown, a pixel, a peripheral circuit, and many wirings connecting them are formed on the lower substrate 200. In this case, the transparent electrode is formed on the entire upper substrate 100.

2 (a) and 2 (b) are cross-sectional views taken along line A-A 'of the driving circuit section of FIG. 1, (a) shows a case where liquid crystal is filled in the driving circuit section, and (b) shows a driving circuit section. The case where the seal is filled in is shown. Reference numeral “20” denotes a color filter, “30” denotes a pixel, “40” denotes a transparent electrode, “50” denotes a liquid crystal material, “60” denotes a wiring, and “70” denotes a peripheral circuit portion.

The transparent electrode 40 is formed on the entire surface of the upper substrate 100 where the color filter 20 is formed so as to overlap the driving circuit unit 70 and the wiring 60 formed on the lower substrate 200.

FIG. 3A is a circuit diagram showing an example of a driving circuit constructed using a polysilicon TFT, and FIG. 3B is a bus line and an electrical node of FIG. 3A, respectively. The circuit diagram further includes a parasitic capacitance existing between an electrical node, a top plate transparent electrode, and two electrodes.

The driving circuit is configured to form sequential and combinational logic with several bus lines. At this time, each of the bus lines and the nodes inside each circuit looks at the transparent electrode formed on the upper substrate with the liquid crystal material or the encapsulant interposed therebetween. This structure increases parasitic capacitances on each bus line and node, causing signal delays on the bus lines and an increase in charging time of each node. This degrades the overall operating characteristics of the built-in drive circuit.

4A is a timing diagram showing a signal input to a bus line and a signal delayed by parasitic capacitance, and FIG. 4B is a node signal and parasitic capacitance when the signal and parasitic capacitance at an ideal node are small. Is a timing diagram showing the node signal in the case where is large, an example of the effect of the signal delay on the bus line and the increasing charging time at each node is shown schematically.

In general, the maximum operating frequency that a bus line can pass

[Equation 1]

fmax ∝ / RC

(R: resistance of bus line, C: capacitance of bus line)

Increasing the parasitic capacitance increases the capacitance value of the bus line, thereby lowering the maximum operating frequency value and causing a delay effect on the circuit using the bus line signal, thereby reducing the overall operation characteristics of the circuit. In addition, an increase in charging time due to an increase in parasitic capacitance at each node also lowers the maximum operating frequency and causes a signal delay, resulting in deterioration of the overall operating characteristics.

SUMMARY OF THE INVENTION In order to improve operating characteristics of a liquid crystal display, the present invention provides a transparent electrode which does not overlap or only partially overlaps with a built-in driving circuit, thereby reducing capacitance values parasitic at bus lines and respective electrical nodes. It is done.

Fig. 5 is a schematic diagram showing a planar structure of a polysilicon TFT LCD according to the present invention having a built-in driving circuit, wherein reference numeral 10 denotes a pixel portion, numeral 12 denotes a data driver, numeral 14 denotes a gate driver. "16" represents a pad array, "42" represents a transparent electrode, "100" represents an upper substrate, and "200" represents a lower substrate.

Although not shown, a color filter and a transparent electrode are formed on the upper substrate 100, and although not shown, a pixel, a peripheral circuit, and many wirings connecting them are formed on the lower substrate 200. At this time, the transparent electrode 42 is formed in a region where the peripheral circuit is formed so as not to overlap with the peripheral circuits (for example, the data driver 12 and the gate driver 14) formed on the lower substrate 200. It is not formed.

For example, the transparent electrode 42 is formed only in an area overlapping the pixel portion 10.

6A and 6B are cross-sectional views taken along line A-A 'of the driving circuit of FIG. 5, (a) illustrates a case where a liquid crystal material is filled in the driving circuit, and (b) The case where a sealing agent is filled in a circuit part is shown. Reference numeral “20” denotes a color filter, “30” denotes a pixel, “42” denotes a transparent electrode, “50” denotes a liquid crystal material, “60” denotes a wiring, and “70” denotes a peripheral circuit portion.

The transparent electrode 42 is formed so as not to overlap the driving circuit unit 70 and the wiring 60 formed on the lower substrate 200. This is performed by depositing the transparent electrode 42 on the upper substrate 100 on which the color filter 20 is formed and removing the transparent electrode in a portion overlapping the driving circuit 70 formed on the lower substrate 200. Form in steps.

5 and 6 illustrate only the case where the transparent electrode does not overlap at all with the driving circuit, the transparent electrode overlaps only one of the data driver and the gate driver constituting the driving circuit and the bus constituting each driver. Of course, even if the line and logic portions do not overlap only with the bus line, the effect sought by the present invention can be achieved. In this case, the bus line not overlapping with the transparent electrode may be a bus line of the data driver, a bus line of the gate driver, or a bus line of both the data driver and the gate driver.

5 and 6 illustrate only a case in which a color filter and a transparent electrode are formed on an upper substrate, and a pixel and a driving circuit are formed on a lower substrate, but a pixel and a driving circuit are formed on an upper substrate, and a lower substrate. Of course, even if the color filter and the transparent electrode is formed, the effect pursued by the present invention can be achieved.

The present invention is not limited to the above embodiments, and it is apparent that many modifications are possible by one of ordinary skill in the art within the technical idea of the present invention.

According to the thin film transistor liquid crystal display according to the present invention and a method of manufacturing the same, the parasitic capacitance between the transparent electrode and the driving circuit can be reduced by forming the transparent electrode so as not to overlap the driving circuit, thereby reducing the signal delay. As the signal delay decreases, the maximum operating frequency value at a specific operating voltage increases, and the minimum operating voltage required to achieve a specific operating frequency decreases.

1 is a schematic diagram showing a planar structure of a general polysilicon TFT LCD in which a driving circuit is incorporated.

2A and 2B are cross-sectional views taken along line A-A 'of the driving circuit of FIG. 1, (a) shows a case where a liquid crystal material is filled in the driving circuit, and (b) shows driving. The case where a seal is filled in a circuit part is shown.

FIG. 3A is a circuit diagram showing an example of a driving circuit constructed using a polysilicon TFT, and FIG. 3B is a bus line and an electrical node of FIG. 3A, respectively. The circuit diagram further includes a parasitic capacitance existing between an electrical node, a top plate transparent electrode, and two electrodes.

4A is a timing diagram showing a signal input to a bus line and a signal delayed by parasitic capacitance, and FIG. 4B is a node signal and parasitic capacitance when the signal and parasitic capacitance at an ideal node are small. Is a timing diagram showing the node signal in the case where is large.

5 is a schematic diagram showing a planar structure of a polysilicon TFT LCD according to the present invention in which a driving circuit is incorporated.

6A and 6B are cross-sectional views taken along line A-A 'of the driving circuit of FIG. 5, (a) illustrates a case where a liquid crystal material is filled in the driving circuit, and (b) The case where a sealing agent is filled in a circuit part is shown.

Claims (6)

A first substrate on which a driving circuit and a pixel are formed; And A second substrate disposed to face the first substrate, the second substrate having a color filter and a transparent electrode designed to not overlap with an area where the driving circuit is formed; The encapsulant is filled between the drive circuit of the said 1st board | substrate and the said 2nd board | substrate, The thin film transistor liquid crystal display device characterized by the above-mentioned. A first substrate on which a driving circuit comprising a data driver and a gate driver and a pixel are formed; And A second substrate disposed to face the first substrate and having a color filter and a transparent electrode designed to partially overlap with any one of the data driver and the gate driver; The encapsulant is filled between the drive circuit of the said 1st board | substrate and the said 2nd board | substrate, The thin film transistor liquid crystal display device characterized by the above-mentioned. The method of claim 2, And the transparent electrode is designed so as not to overlap only the bus line among the bus line and the logic part constituting each driver. Providing a first substrate comprising a drive circuit and a plurality of pixels; Providing a second substrate, on which a color filter is formed, opposite the first substrate; Depositing a transparent electrode on an upper surface of the second substrate on which the color filter is formed; Removing a predetermined portion of the transparent electrode overlapping the driving circuit of the first substrate; And And attaching an encapsulant between the driving circuit of the first substrate and the second substrate. Providing a first circuit comprising a plurality of pixels and a driving circuit having a data driver and a gate driver; Providing a second substrate, on which a color filter is formed, opposite the first substrate; Depositing a transparent electrode on an upper surface of the second substrate on which the color filter is formed; Removing a portion of the transparent electrode overlapping at least one of a data driver and a gate driver of the first substrate; And And attaching an encapsulant between the driving circuit of the first substrate and the second substrate. The method of claim 5, And removing the transparent electrode so as not to overlap only the bus line among the bus line and the logic part constituting each driver.

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