KR100309765B1 - Device and method for driving matrix type lcd - Google Patents

Abstract

PURPOSE: A matrix type LCD driving device and a method thereof are provided to overlap scanning electrode driving signals for increasing a selection time of the scanning electrodes to improve the response of the liquid crystal, and reduce a differential waveform abandoned by a driving signal of unselected scanning electrodes by passing an intermediate level in case of state change of the signal electrode driving signal, thereby reducing cross talk of the liquid crystal. CONSTITUTION: A matrix type LCD driving device includes an LCD panel(50) formed with scanning electrodes and signal electrodes in the matrix structure and aligned with liquid crystal where the scanning electrodes crossing the signal electrodes, a control part(10) receiving data signals and vertical and horizontal synchronization signals and outputting driving timing control signals and the data signals, a driving voltage generating part(20) for outputting voltage signals of certain levels required for driving signals to a signal electrode driving part(30) and a scanning electrode driving part(40), the scanning electrode driving part receiving the driving timing control signal and respective level voltage signals for outputting a scanning electrode driving signal, and the signal electrode driving part receiving the driving timing signal and the data signal from the control part and the respective level voltage signals from the driving voltage generating part for outputting a signal electrode driving signal.

Description

Driving device of matrix type liquid crystal display and driving method thereof

FIG. 1 is a block diagram showing a driving device of a matrix liquid crystal display device according to an embodiment of the present invention.

2 is a waveform diagram showing a drive signal of a conventional matrix liquid crystal display device,

3 is a waveform diagram showing a scan electrode driving signal and a signal electrode driving signal of a conventional matrix liquid crystal display device;

4 is a waveform diagram showing that the scan electrode driving signal is delayed on the electrode in the conventional matrix liquid crystal display and that the differential waveform caused by the data signal is induced in the unselected scan electrode.

5 is a waveform diagram illustrating light transmission characteristics according to an applied voltage of a general liquid crystal,

6 is a waveform diagram showing a scan electrode driving signal and a signal electrode driving signal in the matrix type liquid crystal display according to the embodiment of the present invention,

FIG. 7 is a waveform diagram illustrating scan electrode driving signals when driving a plurality of scan electrodes simultaneously in a matrix type liquid crystal display according to an exemplary embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

10: control unit 20: drive voltage generation unit

30: signal electrode driver 40: scan electrode driver

50: liquid crystal panel

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving apparatus for a matrix type liquid crystal display device and a driving method thereof, wherein the matrix type liquid crystal display improves the response characteristics of a liquid crystal by providing an overlapping section to the scan electrode driving signal and having an intermediate level to the signal electrode driving signal. A driving device of the device and a driving method thereof.

In general, a driving method for operating a liquid crystal display device includes a one-line sequential driving method (APT: Alto-pleshko Tech) that sequentially drives one scanning electrode and a plurality of scanning electrodes that are simultaneously selected and corresponding to the electrode electrodes. There is a plural-line simultaneous driving method in which the driving signal is processed through the data processing circuit, and there is also an Orthogonal function driving-active driving method.

5 is a waveform diagram showing light transmission characteristics according to an applied voltage of a general liquid crystal, and FIG. 3 is a waveform diagram showing a scan electrode driving signal and a signal electrode driving signal of a conventional matrix liquid crystal display.

According to the one-line sequential driving method, when scan electrode Y ₁ is selected, signals of X ₁ to X _M which are driving signals of the signal electrode are simultaneously applied to simultaneously drive the liquid crystal cells of the corresponding line. Operation as described above, as the third is shown in Figure (a) for one frame period Y ₁ → Y ₂ → ... The sequence is repeatedly executed up to Y _N. The dotted line in FIG. 3 (b) shows the driving signal X _N of the specific signal electrode, and the solid line shows when the scan electrode driving signal Y _N corresponding to the signal electrode is high.

In the one-line sequential driving method, the number of lines is defined by a duty concept. For example, when 240 scan electrodes are sequentially driven, the scan electrode driving signal has a duty cycle of 1/240.

2 is a waveform diagram showing a drive signal of a conventional matrix liquid crystal display device, which is driven by a one-line sequential driving method. FIG. 2A shows the scan electrode driving signal, FIG. 2B shows the signal electrode driving signal, and FIG. 2C shows the scan electrode driving signal and the signal electrode driving signal. Shows a voltage waveform applied directly to the liquid crystal.

In the above, the scan electrode driving signal and the signal electrode driving signal are applied with the polarity being inverted every one frame, which is to prevent the deterioration of the liquid crystal and extend the life of the liquid crystal display. In addition, the voltage directly applied to the liquid crystal shown in FIG. 2C is an amount obtained by the voltage difference between the scan electrode driving signal and the signal electrode driving signal.

However, in the one-line sequential driving method as described above, as the number of lines of the display device increases according to the duty concept, the time applied to the one line decreases, so that the driving signal size of the scan electrode is relatively increased. That is, as the number of lines increases, the time for selecting one line decreases by that amount, and thus, the liquid crystal cells positioned in each line cannot be sufficiently driven, resulting in poor reaction speed and response characteristics of the liquid crystal itself.

Another problem is cross talk, which is a display characteristic of a liquid crystal display device having a simple matrix structure. FIG. 4 is a waveform diagram showing that the scan electrode driving signal is delayed by the R and C values on the electrode in the conventional matrix liquid crystal display and that the differential waveform caused by the data signal change is induced in the unselected scan electrode. .

As shown in (b) of FIG. 4, when the state of the signal electrode driving signal changes from high to low or from low to high, a differential waveform is induced in the unselected scan electrode driving signal, and as a result, is directly applied to the liquid crystal. The effective voltage value is increased or decreased.

When the effective voltage value applied directly to the liquid crystal increases or decreases as described above, an error in the effective voltage applied to the liquid crystal is compared with the case where the differential waveform is not induced in the unselected scan electrode driving signal because the state of the signal electrode driving signal does not change. Is generated, which is one of the causes of crosstalk generated in the liquid crystal display.

On the other hand, according to the multi-line simultaneous driving method as another driving method of the liquid crystal, a predetermined number of scan electrodes form a subgroup, and a scan electrode driving signal is applied in units of the subgroups, and the scan electrode driving signals in the subgroup units are applied. The corresponding signal electrode drive signal is applied.

A detailed operation example of the multi-line simultaneous driving method is shown in "Optimum Row Functions and Algorithms for Active Addressing" of SID'93 Digest p89 to p92, and is mainly applied to a liquid crystal display device requiring high-speed response characteristics.

However, the multi-line simultaneous driving method also decreases the pulse width of the scan electrode driving signal and increases the scan electrode signal size as the number of scan players increases, and the signal electrode driving signal has a plurality of values and a large signal level. Therefore, when the state of the signal electrode driving signal changes, the voltage waveform induced by the scan electrode driving signal also becomes large, so that the error of the effective voltage applied directly to the liquid crystal becomes larger.

When the size of the liquid crystal panel of the liquid crystal display device is increased, the resistance of the transparent electrode (ITO: Indium Tin Oxide), which is a material constituting the scan electrode in the liquid crystal panel, increases, so that the scan electrodes are disposed between the left and right sides of the liquid crystal as shown in FIG. The driving signal is delayed. The delay of the scan electrode driving signal may cause an error of an effective voltage applied directly to the liquid crystal, thereby causing flicker.

Therefore, an object of the present invention is to solve the conventional technical problems as described above, and to increase the driving time of the selected scan electrode driving signal by setting the overlapping driving period between the scan electrode driving signals, thereby increasing the size of the selected scan electrode driving signal. In addition, the time applied to the liquid crystal is increased by increasing the selected time of each scan line, thereby improving the response characteristics of the liquid crystal.

Another object of the present invention is to change the level of the intermediate level or reverse polarity (data voltage is not full low or full high) in the interval where the scan electrode driving signal is superimposed after the signal electrode driving signal is applied high or low. In this way, the differential waveform excited by the scan electrode driving signal in accordance with the change of the signal electrode driving signal can be reduced, and the crosstalk problem of the liquid crystal can be remarkably improved.

The configuration of the drive device of the matrix type liquid crystal display device to achieve the above object is a voltage signal of each voltage level required for the intermediate level of the drive signal and the signal electrode drive signal applied to the scan electrode and the signal electrode of the liquid crystal panel A driving voltage generating unit for generating a; From the input data signal and vertical and horizontal registration signals, a driving timing control signal for one-line sequential driving or plural-line simultaneous driving and a data signal for determining a high or low of the liquid crystal cell are generated. A controller configured to overlap each other by a predetermined pulse width in a section, and to pass an intermediate level by a pulse width corresponding to an overlapping section of the scan electrode driving signal when the data signal is changed from high to low or low to high; A scan electrode driver for sequentially applying a corresponding level among the voltage signals generated by the drive voltage generator to the scan electrodes of the liquid crystal panel as a drive signal according to the drive timing control signal generated by the controller; When the scan electrode driving signal is applied by the driving timing control signal and the data signal generated by the controller, the voltage level of the driving voltage generator corresponding to the data signal is simultaneously applied to each signal electrode of the liquid crystal panel as the signal electrode driving signal. It consists of a signal electrode driver.

By the above configuration, it will be described with reference to the accompanying drawings the most preferred embodiment which can easily implement the present invention as follows.

1 is a block diagram showing a driving device of a matrix liquid crystal display according to an embodiment of the present invention, and FIG. 6 is a scan electrode driving signal and signal electrode driving in a matrix liquid crystal display according to an embodiment of the present invention. FIG. 7 is a waveform diagram showing signals, and FIG. 7 is a waveform diagram showing scan electrode and signal electrode driving signals when a plurality of scan electrodes are simultaneously driven in a matrix type liquid crystal display according to an exemplary embodiment of the present invention. 8 is a waveform diagram showing a driving electrode and a signal electrode driving diagram in which all contracted pixels are designed to have a constant operating frequency as another embodiment of the present invention.

As shown in FIG. 1, the configuration of the driving apparatus of the matrix type liquid crystal display device according to the embodiment of the present invention is that the liquid crystal is formed at the point where the scan electrode and the signal electrode of the matrix structure are formed and the scan electrode and the signal electrode cross each other. An arrayed liquid crystal panel 50; A controller 10 for inputting a data signal and a vertical and horizontal synchronization signal to output a driving timing control signal and a data signal; A driving voltage generator 20 for outputting a voltage signal of each level required for the driving signal to the signal electrode driver 30 and the scan electrode driver 40; A scan electrode driver 40 for receiving a driving timing control signal from the controller 10 and a voltage signal of each level from the driving voltage generator 20 to output a scan electrode driving signal; The control unit 10 includes a driving timing control signal and a data signal, and a driving voltage generation unit 20 receives a voltage signal of each level so as to output a signal electrode driving signal.

The driving mechanism of the matrix type liquid crystal display device and the driving method thereof according to the embodiment of the present invention by the above configuration are as follows.

First, when the data signal and the vertical and horizontal synchronization signals are input to the controller 10, the operation of the circuit is started. The controller 10 controls the driving timing control signal and the high or low voltage applied to the signal electrode of the liquid crystal panel 50 according to the input line signal and the vertical and horizontal synchronizing signals according to the one-line sequential driving method or the plural-line simultaneous driving method. The data signal is determined.

The driving timing control signal is generated such that the driving signals applied to the scan electrodes of the liquid crystal panel 50 overlap each other adjacent electrodes as shown in FIG. 6 (a). Similarly, when the state changes from high to low or from low to high, the intermediate level is maintained for a time corresponding to the overlapping period of the scan electrode driving signal.

7 shows driving signals of the scan electrode and the signal electrode by the plural-line simultaneous driving method. In the example shown in FIG. 7, the scan electrode driving signals of three lines are formed into subgroups, and orthogonal function values are applied to each line.

On the other hand, the driving voltage generator 20 generates a voltage signal of each level required for the driving signal applied to the scan electrode and the signal electrode of the liquid crystal panel 50 and a voltage signal of the intermediate level required for the signal electrode driving signal. It is output to the signal electrode driver 30 and the scan electrode driver 40.

In the scan electrode driver 40, a corresponding voltage level of the drive voltage generator 20 is selected from the drive timing control signal input from the controller 10 to generate a scan electrode drive signal, and the scan electrode drive signal is the sixth. As shown in FIGS. 7A and 7B, the driving timing control signals overlap each other for a predetermined period and are sequentially applied to the scan electrodes of the liquid crystal panel 50.

The high section of the scan electrode driving signal increases due to the overlap between the scan electrode driving signals and the high level of the scan electrode driving signal decreases. That is, the selection time applied to the scan electrodes of the liquid crystal panel is increased to improve the liquid crystal response characteristics.

In the signal electrode generator 20, data signals input from the controller 10 are stored in parallel, and a voltage level corresponding to each data signal is selected from one of the voltage signals input from the driving voltage generator 20. The voltage signals for driving each of the selected signal electrodes are simultaneously applied to the signal electrodes of the liquid crystal panel 50 when the scan electrode driving signal is applied to the scan electrodes of the liquid crystal panel 50.

The signal electrode driving signal corresponds to the overlapping period of the scan electrode driving signal from the data signal of the control unit 10 as shown in FIG. 7B at the time when the driving time of one scan electrode is over and the adjacent scan electrode and the selection signal overlap. The intermediate level is selected from the voltage signals input from the driving voltage generator 20 so that the signal electrode driving signal maintains the intermediate level by the pulse width.

As described above, passing the intermediate level when the signal electrode driving signal changes from low to high or high to low reduces the differential waveform induced in the unselected scan electrode driving signal by reducing the magnitude of the signal change of the signal electrode driving signal. It is to let.

When the differential waveform induced by the scan electrode driving signal is reduced, the error of the effective voltage applied directly to the liquid crystal is also reduced, thereby reducing the occurrence of the crosstalk phenomenon.

The scan electrode driving signal is applied by the scan electrode driver 40 in one line or subgroup unit, and the signal electrode driving signal is applied to the liquid crystal panel 50 whenever the scan electrode driving signal is applied to the liquid crystal panel 50. By applying to the signal electrodes of the respective liquid crystal cells of the liquid crystal panel 50 is driven to an appropriate level, the desired image information can be displayed.

On the other hand, FIG. 8 is another embodiment of the present invention. In order to allow all liquid crystal cells to operate at a fixed frequency, as shown in FIG. In the ON state, as shown in (b) of FIG. 8, when the overlapping time is reached, the change is higher than the intermediate level. In another embodiment of the present invention, since the intermediate level is an unselected signal level of the scan electrode, AC driving is always possible and the frequency is fixed, thereby solving the problem of V _th change of liquid crystal according to frequency.

Table 1 below is experimental data obtained when the scan electrode driving signals are superimposed and subjected to an intermediate level when the state of the signal electrode driving signals changes according to the exemplary embodiment of the present invention.

As described above, in the embodiment of the present invention, the scan electrode driving signals overlap each other, thereby increasing the selection time of the scan electrodes, thereby improving the response characteristics of the liquid crystal, and reducing the intermediate level when the state of the signal electrode driving signals changes. The present invention provides a driving apparatus and a driving method of the matrix type liquid crystal display device having the effect of reducing the crosstalk of the liquid crystal by reducing the differential waveform induced by the unselected scanning electrode driving signal.

Claims (4)

A driving voltage generator for generating a voltage signal of each voltage level required for an intermediate level of the driving signal and the signal electrode driving signal applied to the scan electrode and the signal electrode of the liquid crystal panel; A driving timing control signal for sequential driving of one line or simultaneous driving of multiple lines and a data signal for determining a high or low of the liquid crystal cell are generated from data signals inputted from outside and vertical and horizontal synchronization signals, and each scan electrode driving signal. The overlapping scan signals adjacent to each other in the high section are overlapped by a predetermined pulse width, and when the data signal changes from high to low or low to high level, the scan signals are passed through the intermediate level by the pulse width corresponding to the overlapping section of the scan electrode driving signal. A controller for outputting a driving timing control signal; A scan electrode driver configured to apply a corresponding level among the voltage signals generated by the drive voltage generator to a scan electrode of the liquid crystal panel based on the drive timing control signal; And applying a voltage level of the driving voltage generator corresponding to the data signal as a signal electrode driving signal based on the application of the scan electrode driving signal based on the driving timing control signal and the data signal to each signal electrode of the liquid crystal panel. And a signal electrode driver to be applied. A method of driving a matrix type liquid crystal display device comprising a liquid crystal panel in which a scan electrode and a signal electrode having a matrix structure are formed and liquid crystals are arranged at a point where the scan electrode and the signal electrode intersect, (a) a data signal from outside And generating and outputting a timing control signal and a voltage signal for controlling the generation of the scan electrode driving signal and the generation of the signal electrode driving signal according to the application of the horizontal and vertical synchronization signals. (b) generating a scan electrode driving signal to overlap the scan electrodes adjacent to each other on the liquid crystal panel for a predetermined period in response to the timing control signal, and sequentially supplying the generated scan electrode driving signal to the scan electrode line of the liquid crystal panel; step; And (c) maintaining the intermediate level by a pulse width corresponding to an overlap period of the scan electrode driving signal when the signal electrode driving signal changes from high to low or low to high in response to the timing control signal. And generating a signal electrode driving signal and supplying the generated signal electrode driving signal to a data line of the liquid crystal panel. The method of claim 2, wherein the constant section overlapping method of step (b) comprises a one-line sequential driving method of sequentially driving the scan electrodes one line at a time, and forming the scan electrodes in a plurality of sub-groups in units of the sub-groups. A drive method for a matrix type liquid crystal display device, characterized in that any one of a plurality of line simultaneous driving methods for driving simultaneously. A method of driving a matrix type liquid crystal display device comprising a liquid crystal panel in which a scan electrode and a signal electrode having a matrix structure are formed and liquid crystals are arranged at a point where the scan electrode and the signal electrode intersect, (a) a data signal from outside And generating and outputting a timing control signal and a voltage signal for controlling the generation of the scan electrode driving signal and the generation of the signal electrode driving signal according to the application of the horizontal and vertical synchronization signals. (b) generating a scan electrode driving signal to overlap the scan electrodes adjacent to each other on the liquid crystal panel for a predetermined period in response to the timing control signal, and sequentially supplying the generated scan electrode driving signal to the scan electrode line of the liquid crystal panel; step; And (c) a signal voltage value indicating on / off so that the voltage level of the signal electrode is reverse polarity at the time overlapping with the adjacent scan electrode after the end of the selected driving time of the one scan electrode in response to the timing control signal. Generating a signal electrode driving signal having a plurality of liquid crystal pixels always having the same frequency component so as to have a small value and maintained for an overlapping period, and supplying the signal electrode driving signal to a data line of the liquid crystal panel; Method of driving display device.