KR20060134292A - Source driver integrated circuit for driving liquid crystal display and liquid crystal display for having the same - Google Patents

Abstract

An LCD(Liquid Crystal Display) device and a source driver IC for driving the LCD device are provided to prevent image degradation by effectively compensating the difference between gradation voltages from plural source driving circuits. A source driver IC for an LCD device includes plural source drivers. The source driver includes a gradation voltage supply unit and a gradation voltage compensating unit(220). The gradation voltage supply unit supplies a gradation voltage corresponding to input image data to an LCD panel. The gradation voltage compensating unit compensates the difference between a first gradation voltage, which is supplied from the gradation voltage supply unit of one of the source drivers, and a second gradation voltage, which is supplied from the gradation voltage supply unit of another source driver.

Description

Source driver integrated circuit for driving a liquid crystal display and a liquid crystal display including the same {Source driver integrated circuit for driving liquid crystal display and liquid crystal display for having the same}

1 is a configuration diagram of a liquid crystal display device to which a source driver integrated circuit for driving a liquid crystal display device according to an exemplary embodiment of the present invention is applied.

2 is a schematic block diagram of a source driver integrated circuit for driving a liquid crystal display according to an exemplary embodiment of the present invention.

3 is a configuration diagram illustrating a source driver of FIG. 2.

4 is a detailed configuration diagram of the gray voltage correction unit of FIG. 3.

5 is a circuit diagram of the differential amplifier of FIG. 4.

6 is a waveform diagram of an input signal and an output signal of the pulse signal providing unit of FIG. 4.

7A and 7B are detailed block diagrams of the charge providing unit of FIG. 4.

(Explanation of symbols for the main parts of the drawing)

110, 210: gradation voltage providing unit 120, 220: gradation voltage correction unit

221: differential amplifier 222: pulse signal providing unit

223: charge providing unit

The present invention relates to a source driver integrated circuit for driving a liquid crystal display and a liquid crystal display including the same, and more particularly, a plurality of source drivers in a source driver integrated circuit for driving a liquid crystal display including a plurality of source driving circuits. The present invention relates to a source driver integrated circuit for driving a liquid crystal display device capable of effectively correcting a difference in a gradation voltage provided by the same, and a liquid crystal display device including the same.

In today's information society, the role of electronic displays has become very important, and various electronic displays have been widely used in various industrial fields. In the electronic display device field, electronic display devices having new functions suitable for the demands of the information society, which have been continuously developed and diversified, are continuously being developed. In general, an electronic display device refers to a device that transmits various pieces of information to a human through vision. That is, an electronic display device refers to an electronic device that converts an electronic information signal output from various electronic devices into an optical information signal that can be recognized by a human eye, and is a device that plays a role of a bridge between humans and electronic devices. It can be said.

In such an electronic display device, when an optical information signal is displayed by a light emitting phenomenon, it is referred to as a light emitting display device, and when it is displayed by light modulation due to reflection, scattering, or interference phenomenon, it is called a light receiving display device. Light emitting displays, also called active display devices, include cathode ray tubes (CRTs), plasma display panels (PDPs), organic electroluminescent displays (OELDs), light emitting diodes ( Light Emitting Diode (LED) etc. can be mentioned. The light receiving display device, which is called a passive display device, may include a liquid crystal display (LCD), an electrophoretic image display (EPID), and the like.

Cathode ray tube display device, which is used for television and computer monitor, and has the longest history, has the highest market share in terms of economy, but has many disadvantages such as heavy weight, large volume and high power consumption. .

Recently, due to the rapid progress of semiconductor technology, there is a demand for a flat panel display device as an electronic display device suitable for a new environment in accordance with the trend of lowering and lowering power of various electronic devices and miniaturization, thinning, and lightening of electronic devices. It is rapidly increasing. Accordingly, flat panel display devices such as a liquid crystal display (LCD), a plasma display device (PDP), an organic EL display device (OELD), and the like have been developed, and among these flat panel display devices, it is easy to miniaturize, light weight, and thinner. In particular, liquid crystal display devices having low power consumption and low driving voltage are drawing attention.

In the liquid crystal display, a liquid crystal material having an anisotropic dielectric constant is injected between an upper transparent insulating substrate on which a common electrode, a color filter, a black matrix, and the like are formed, and a lower transparent insulating substrate on which a switching element and a pixel electrode are formed. By applying different voltages to the electrodes and the common electrode, the intensity of the electric field formed on the liquid crystal material is adjusted to change the molecular arrangement of the liquid crystal material, thereby controlling the amount of light transmitted through the transparent insulating substrate, thereby controlling the desired image data. It is a display device to express. In the liquid crystal display, a thin film transistor liquid crystal display (TFT LCD) using a thin film transistor (TFT) element as a switching element is mainly used.

The liquid crystal display requires a source driver integrated circuit that provides a gray voltage corresponding to the image data in order to apply a voltage corresponding to the image data to the liquid crystal material. Such a source driver integrated circuit is not composed of a single driver circuit but is composed of a plurality of driver circuits. The plurality of driving circuits do not provide the same gray voltage, but provide different gray voltages.

In the conventional liquid crystal display, desired image data is represented by using a source driver integrated circuit composed of a plurality of driving circuits. Therefore, in the conventional liquid crystal display device, by using a source driver integrated circuit that provides different gray scale voltages from a plurality of driving circuits, image quality such as streaks on the screen of the liquid crystal display device is deteriorated.

Accordingly, a technical object of the present invention is to drive a liquid crystal display device capable of effectively correcting a difference in gray voltages provided by a plurality of source driver circuits in a source driver integrated circuit for driving a liquid crystal display device including a plurality of source driver circuits. To provide a source driver integrated circuit for the purpose.

Another object of the present invention is to provide a liquid crystal display device including the above-described source driver integrated circuit for driving the liquid crystal display device.

The technical problem to be achieved by the present invention is not limited to the technical problems mentioned above, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

According to another aspect of the present invention, there is provided a source driver integrated circuit for driving a liquid crystal display device, the gray voltage providing unit and the gray voltage providing unit providing a gray voltage corresponding to input image data to a liquid crystal panel. And a plurality of source drivers including a gray voltage corrector for correcting a difference between the gray voltage provided from the gray level voltage and the gray voltage provided from the other source driver.

In a source driver integrated circuit for driving a liquid crystal display according to an exemplary embodiment of the present invention, a gradation voltage provided by the gradation voltage correction unit is greater than a gradation voltage provided by the gradation voltage providing unit of the other source driver. In this case, the gradation voltage provided from the gradation voltage providing unit is reduced, and when the gradation voltage provided from the gradation voltage providing unit is smaller than the gradation voltage provided from the gradation voltage providing unit of the other source driving unit, the gradation voltage providing unit It is desirable to increase the gradation voltage provided from.

In addition, a source driver integrated circuit for driving a liquid crystal display according to an exemplary embodiment of the present invention may be provided to the gray voltage correction unit through a conductive line formed on the liquid crystal panel with a gray voltage provided from the gray voltage providing unit of the other source driver. It is preferred to be delivered.

Also, in the source driver integrated circuit for driving the liquid crystal display according to the exemplary embodiment of the present invention, a gray voltage provided by the gray voltage correcting unit from the gray voltage providing unit and a gray voltage provided from the gray voltage providing unit of the other source driving unit. A differential amplifier for amplifying the voltage of the difference, a pulse for providing a pulse signal of which the time width is increased in proportion to the difference between the voltage amplified by the differential amplifier and the gray voltage provided from the gray voltage supply unit of the other source driver It is preferable to include a charge providing unit which increases or decreases the gradation voltage provided from the gradation voltage providing unit according to the signal providing unit and the pulse signal provided from the pulse signal providing unit.

The liquid crystal display according to the exemplary embodiment of the present invention for achieving the another technical problem includes the above-described source driver integrated circuits for driving the liquid crystal display.

Specific details of other embodiments are included in the detailed description and the drawings. Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. Like reference numerals refer to like elements throughout.

A liquid crystal display device to which a source driver integrated circuit for driving a liquid crystal display device according to an exemplary embodiment of the present invention is applied will be described with reference to FIG. 1. 1 is a configuration diagram of a liquid crystal display device to which a source driver integrated circuit for driving a liquid crystal display device according to an exemplary embodiment of the present invention is applied.

As shown in FIG. 1, in a liquid crystal display device to which a source driver integrated circuit for driving a liquid crystal display device according to an exemplary embodiment of the present invention is applied, m * n liquid crystal cells Clc are arranged in a matrix type and m data lines are provided. Pixels are formed at the intersections of the pixels D1 to Dm and the n gate lines G1 to Gn, and the liquid crystal panel 20 having the thin film transistor TFT formed thereon, and the data of the liquid crystal panel 20. A source driver integrated circuit 40 providing a gray voltage to the lines D1 to Dm, a gate driver integrated circuit 60 providing a scan signal to the gate lines G1 to Gn, and a source driver integrated circuit ( A gamma voltage supply unit 80 for providing a gamma voltage to the 40, and a timing controller 10 for controlling the gate driver integrated circuit 60 and the source driver integrated circuit 40.

The liquid crystal panel 20 includes a plurality of liquid crystal cells Clc disposed in a matrix at the intersections of the data lines D1 to Dm and the gate lines G1 to Gn. Each of the thin film transistors TFT formed in the liquid crystal cell Clc transfers a pixel signal provided from the data lines D1 to Dm to the liquid crystal cell Clc in response to a scan signal provided to the gate lines G1 to Gn. Supply. In addition, a storage capacitor Cst is formed in each of the liquid crystal cells Clc. The storage capacitor Cst is formed between the pixel electrode of the liquid crystal cell Clc and the front gate line or between the pixel electrode of the liquid crystal cell Clc and the common electrode line to maintain a constant voltage of the liquid crystal cell Clc. Let's do it.

The gamma voltage supply unit 80 provides a plurality of gamma voltages to the source driver integrated circuit 40 so that grayscale voltages can be generated.

The timing controller 10 generates a gate control signal GCS and a data control signal DCS including a gate driver start pulse GSP, a gate driver clock signal GCP, and the like by using the input synchronization signals. The control signal GCS is provided to the gate driver integrated circuit 60, and the data control signal DCS is provided to the source driver integrated circuit 40. In addition, the timing controller 10 rearranges input image data R, G, and B and provides them to the source driver integrated circuit 40.

The gate driver integrated circuit 60 includes one gate driver integrated circuit start pulse GSP and the number n of gate lines G1 to Gn in one frame period in the timing controller 10. The gate lines are provided by receiving the integrated circuit clock signals GCP and generating a scan signal every one horizontal period H of the gate driver integrated circuit clock signals GCP of the number n of the gate lines G1 to Gn. It is provided sequentially to (G1 to Gn). Accordingly, the thin film transistors TFTs connected to the gate lines G1 to Gn are sequentially driven.

The source driver integrated circuit 40 is one horizontal period of the gate driver clock signals GCP of the number n of the gate lines G1 to Gn in response to the data control signal DCS provided from the timing controller 10. The image data R, G, and B for each line (H) are provided to the data lines D1 to Dm. In particular, the source driver integrated circuit 40 uses the gamma voltage from the gamma voltage supply unit 80 as the image data R, G, and B input from the timing controller 10, and the gray level voltage corresponding to the input image data. Is generated and provided to the data lines D1 to Dm.

2 and 3, a source driver integrated circuit for driving a liquid crystal display according to an exemplary embodiment will be described. 2 is a schematic block diagram of a source driver integrated circuit for driving a liquid crystal display according to an exemplary embodiment of the present invention. 3 is a configuration diagram illustrating a source driver of FIG. 2.

A source driver integrated circuit for driving a liquid crystal display according to an exemplary embodiment of the present invention includes a plurality of source drivers SIC_1 to SIC_8, and each of the plurality of source drivers SIC_1 to SIC_8 corresponds to input image data. A gray scale voltage providing unit (for example, 210) for providing the gray scale voltages GV1 to GV8 to the liquid crystal panel 20, and a source driver (for example, a source driver different from the gray scale voltage GV2 provided from the gray voltage providing unit 210). For example, the gray voltage correction unit 220 corrects the difference between the gray voltages GV1 provided from the gray voltage providing unit 110 of SIC_1. Here, the gray voltage GV1 provided from the gray voltage providing unit 110 of the first source driver SIC_1 is connected to the second source driver through a line of glass (LOG) formed on the liquid crystal panel 20. The gray voltage GV2 provided to the gray voltage corrector 220 of the SIC_2 and provided from the gray voltage provider 210 of the second source driver SIC_2 is a conductive line LOG formed on the liquid crystal panel 20. The signal is transmitted to the gray voltage correction unit of the third source driver SIC_3 through the control unit. That is, the grayscale voltage GV1 provided from the grayscale voltage providing unit 110 of the source driver of the previous stage (eg, the first source driver; SIC1) may be transferred through the conductive line LOG formed on the liquid crystal panel 20. The gray level voltage corrector 220 of the source driver of the stage (for example, the second source driver SIC_2) is transferred. However, the gray voltage GV8 provided from the gray voltage providing unit of the eighth source driver SIC_8 is the gray voltage correcting unit of the first source driver SIC_1 through the conductive line LOG formed on the liquid crystal panel 20. 120).

The gray voltage correcting unit (for example, the gray voltage correcting unit of the second source driver SIC_2) 220 may be a source driver (for example, a second voltage different from the gray voltage GV2 provided from the gray voltage providing unit 210). 1 source driver; when larger than the gradation voltage GV1 provided from the gradation voltage providing unit 110 of the SIC_1, the gradation gradation voltage GVA2 reducing the gradation voltage GV2 provided from the gradation voltage providing unit 210. When the gray voltage GV2 provided from the gray voltage providing unit 210 is smaller than the gray voltage voltage GV1 provided from the gray voltage providing unit 110 of the other source driver SIC_1, the gray voltage providing unit The correction gray voltage GVA2 is increased by increasing the gray voltage GV2 provided from 210.

4 to 7B, the gray voltage correcting unit of the source driver integrated circuit for driving the liquid crystal display according to the exemplary embodiment of the present invention will be described. 4 is a detailed configuration diagram of the gray voltage correction unit of FIG. 3. 5 is a circuit diagram of the differential amplifier of FIG. 4. 6 is a waveform diagram of an input signal and an output signal of the pulse signal providing unit of FIG. 4. 7A and 7B are detailed block diagrams of the charge providing unit of FIG. 4.

As shown in FIG. 4, the gray voltage correcting unit 220 is provided from the gray voltage providing unit 110 of the source driver SIC_1 that is different from the gray voltage GV2 provided from the gray voltage providing unit 210. The gray scale voltage provided from the differential amplifier 221 for amplifying the difference of GV1, the voltage DV2 amplified by the differential amplifier 221, and the gray scale voltage study 110 of the other source driver SIC_1. The gradation voltage providing unit 222 is provided according to the pulse signal providing unit 222 providing the pulse signal PV2 whose time width increases in proportion to the difference of the GV1 and the pulse signal PV2 provided from the pulse signal providing unit 222. And a charge provider 223 that increases or decreases the gray voltage GV2 provided from 210 to provide the corrected gray voltage GVA2.

As illustrated in FIG. 5, the differential amplifier 221 may be configured using the operational amplifier OP2 and the resistors R21 and R22. The gray level voltage GV1 provided from the gray level voltage providing unit 110 of the other source driver SIC_1 is applied to the (+) input terminal of the operational amplifier OP2, and to the (−) input terminal of the operational amplifier OP2. One side of the resistor R21 is connected, a resistor R22 is connected between the negative input terminal and the output terminal of the operational amplifier OP2, and the other side of the resistor R21 is provided from the gray scale voltage providing unit 210. The provided gray voltage GV2 is applied. In the differential amplifier 221, when the gray voltage GV2 provided from the gray voltage providing unit 210 is greater than the gray voltage GV1 provided from the gray voltage providing unit 110 of the other source driver SIC_1. The source DV2 may have a voltage DV2 smaller than the gray voltage GV1 provided from the gray voltage providing unit 110 of the other source driver SIC_1, and the gray voltage GV2 provided from the gray voltage providing unit 210 may be a different source. When smaller than the gray voltage GV1 provided from the gray voltage providing unit 110 of the driver SIC_1, the voltage greater than the gray voltage GV1 provided from the gray voltage providing unit 110 of the other source driver SIC_1 ( DV2). The magnitude of the voltage DV2 of the difference between the gray voltages amplified by the differential amplifier 221 may be adjusted by the ratios R22 / R21 of the resistors.

As illustrated in FIG. 6, the pulse signal providing unit 222 may use the gray level voltage provided from the gray level voltage providing unit 110 of the source driver SIC_1 different from the voltage DV2 amplified by the differential amplifier 221. A pulse signal PV2 is provided in which the time widths t1 to t8 are increased in proportion to the difference DV2-GV1 of GV1). Accordingly, when the gray voltage GV2 provided from the gray voltage providing unit 210 is greater than the gray voltage voltage GV1 provided from the gray voltage providing unit 110 of the other source driver SIC_1, the pulse signal providing unit 222 may be used. Provides a negative pulse signal PV2, and the gray voltage GV2 provided from the gray voltage providing unit 210 is provided from the gray voltage providing unit 110 of another source driver SIC_1. In the smaller case, the positive pulse signal PV2 is provided.

As shown in FIGS. 7A and 7B, the charge providing unit 223 includes a charge control unit 223_1, a switching unit 223_2, and a capacitor 223_3, and the capacitor 223_3 includes a gray voltage supply unit 210. The provided gray voltage GV2 is charged. When the positive pulse signal PV2 is provided from the pulse signal providing unit 222, as shown in FIG. 7A, the positive pulse signal PV2 is applied to the charge control unit 223_1 so that the switching unit 223_2 The charge is connected to the charge terminal (+), and charge is charged from the charge controller 223_1 to the capacitor 223_3. The amount of charge charged in the capacitor 223_3 is proportional to the time widths t1 to t4 of the positive pulse signal PV2. Therefore, when the gray voltage GV2 provided from the gray voltage providing unit 210 is smaller than the gray voltage voltage GV1 provided from the gray voltage providing unit 110 of the other source driver SIC_1, the charge providing unit 223 is used. The charge is charged from the charge controller 223_1 to the capacitor 223_3, thereby providing the corrected gray voltage GVA2 in which the gray voltage GV2 provided from the gray voltage provider 210 is increased. Here, the correction gray voltage GVA2 may be increased to the gray voltage GV1 provided from the gray voltage providing unit 110 of the other source driver SIC_1.

When the negative pulse signal PV2 is provided from the pulse signal providing unit 222, as shown in FIG. 7B, the negative pulse signal PV2 is applied to the charge control unit 223_1 so that the switching unit 223_2 It is connected to the charge discharge terminal (−) and charge is discharged from the charge capacitor 223_3 to the charge controller 223_1. The amount of charge discharged from the capacitor 223_3 is proportional to the time width t5 to t8 of the negative pulse signal PV2. Therefore, when the gray voltage GV2 provided from the gray voltage providing unit 210 is greater than the gray voltage GV1 provided from the gray voltage providing unit 110 of the other source driver SIC_1, the charge providing unit 223 may be used. The charge is discharged from the capacitor 223_3 to the charge providing unit 223, thereby providing a corrected gray voltage GVA2 in which the gray voltage GV2 provided from the gray voltage providing unit 210 is reduced. Here, the correction gray voltage GVA2 may be reduced to the gray voltage GV1 provided from the gray voltage providing unit 110 of the other source driver SIC_1.

Since the correction coefficient voltage GVA2 can effectively correct the difference between the gray scale voltages GV1 to GV8 provided by the plurality of source drivers SIC_1 to SIC_8, the correction coefficient voltage GVA2 is applied to the liquid crystal panel 20. As a result, it is possible to effectively suppress deterioration in image quality such as streaks on the screen of the liquid crystal display device caused by the difference in the gray voltages GV1 to GV8.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may be embodied in other specific forms without changing the technical spirit or essential features of the present invention. I can understand that. Therefore, the above-described embodiments will be described in detail so that the disclosure of the present invention may be completed, and those skilled in the art may easily implement the technical idea of the present invention. It is to be understood to be illustrative and not limitative in all respects, as it is provided to fully inform the person skilled in the art the scope of the invention, and the invention is defined only by the scope of the claims. .

The source driver integrated circuit for driving the liquid crystal display device and the liquid crystal display including the same according to the embodiments of the present invention made as described above, even when the plurality of source driving circuits include, the gray level provided by the plurality of source driving circuits. The difference in voltage can be corrected effectively.

Claims (5)

A source driver integrated circuit for driving a liquid crystal display including a plurality of source drivers, The plurality of source drivers, A gray scale voltage providing unit which provides a gray scale voltage corresponding to the input image data to the liquid crystal panel; And And a gradation voltage correcting unit for correcting a difference between the gradation voltage provided from the gradation voltage providing unit and the gradation voltage provided from the gradation voltage providing unit of the other source driving unit. The method of claim 1, The gray voltage correcting unit reduces the gray voltage provided from the gray voltage providing unit when the gray voltage provided from the gray voltage providing unit is greater than the gray voltage provided from the gray voltage providing unit of the other source driver. When the gradation voltage provided from the voltage providing unit is smaller than the gradation voltage provided from the gradation voltage providing unit of the other source driving unit, the gradation voltage provided from the gradation voltage providing unit is increased. Driver integrated circuit. The method of claim 1, And a gray voltage provided from the gray voltage providing unit of the other source driver is transferred to the gray voltage correcting unit through a conductive line formed on the liquid crystal panel. The method of claim 1, The gray voltage correction unit, A differential amplifier for amplifying a voltage of a difference between a gray voltage provided from the gray voltage voltage providing unit and a gray voltage provided from a gray voltage voltage providing unit of the other source driver; A pulse signal providing unit providing a pulse signal having a time width increased in proportion to a difference between a voltage amplified by the differential amplifier and a gray voltage provided from a gray voltage providing unit of the other source driver; And And a charge providing unit for increasing or decreasing a gray voltage provided from the gray voltage providing unit in accordance with a pulse signal provided from the pulse signal providing unit. The method according to claim 1, wherein And a source driver integrated circuit for driving the liquid crystal display device.

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