Flat panel display and driving method thereof

A driving method of a flat panel display capable of reducing a peak current generated in driving the flat panel display is disclosed in which a data pulse is supplied to a data line and a scan pulse is supplied to a scan line in synchronization with the data line. A data pulse having a certain tilt is supplied to the data line or a scan pulse having a certain tilt is supplied to the scan line.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. A flat panel display and its driving method of the present invention are capable of reducing a peak current generated in driving a flat panel display by allowing at least more than one of data (a video data) and a scan data for supplying a data pulse and a scan pulse when the scan pulse is supplied to a scan line so as to be synchronized with the data pulse, to have a certain tilt, of which preferred embodiments will now be described in detail with reference to FIGS. 7 through 12 . FIG. 7 illustrates driving waveforms supplied to a flat type FED in accordance with a first embodiment of the present invention. As shown in FIG. 7 , in the flat type FED, a negative polarity (−) scan pulse (SP) having a certain tilt is sequentially supplied to the scan lines (S 1 ˜Sm) and a positive polarity (&plus;) data pulse (DP) synchronized with the negative polarity scan pulse (SP) is supplied to the data line (D). Electrons are discharge due to a voltage difference between the scan pulse (SP) and the data pulse (DP) from the pixel cell to which the scan pulse (SP) and the data pulse (DP) have been simultaneously supplied. In the first embodiment of the present invention, the scan pulse (SP) supplied to the scan line (S) has a certain tilt, which will now be described in detail with reference to FIG. 8 . FIG. 8 illustrates waveforms showing peak currents generates by the waveforms of FIG. 7 . As shown in FIG. 8 , the scan data (s-data) for generating the scan pulse (SP) having a certain tilt has a certain tilt. When the scan pulse (SP) having a certain tilt is supplied, a peak current (Lip) lower than that of the conventional art according to equation (1) flows to the pixel cell. Thus, a damage to the insulation layer 52 formed as a thin film as shown in FIG. 3 can be minimized. In this respect, the scan data (s-data) signifies a voltage difference between the scan pulse and the data pulse, that is, a voltage pulse applied to one cell. In the first embodiment of the present invention, the scan data (s-data) is increased with a certain tilt, and when it goes beyond a certain voltage, it is sharply increased. Accordingly, two times of peaks current (Lip 1 , Lip 2 ) flow to the insulation layer 52 . That is, when the scan data (s-data) is increased with a certain tilt, the first peak current (Lip 1 ) flows, and when the scan data (s-data) rapidly goes up to above a certain voltage (a voltage higher than a threshold voltage), the second peak current (Lip 2 ) flows. These peak currents have a lower voltage than that of the conventional art, a damage to the insulation layer 52 can be minimized. FIG. 9 illustrates driving waveforms supplied to a flat type FED in accordance with a second embodiment of the present invention. As shown in FIG. 9 , in a flat type FED in accordance with a second embodiment of the present invention, a negative polarity (−) scan pulse (SP) having a certain tilt is sequentially supplied to the scan line (S), and a data pulse (DP) synchronized with the negative polarity (−) scan pulse (SP) and having a certain tilt is supplied to the data line (D). Electrons are discharged due to a voltage difference between the scan pulse (SP) and the data pulse (DP) from the pixel cell to which the scan pulse (SP) and the data pulse (DP) have been simultaneously supplied. In the second embodiment of the present invention, in order to supply the scan pulse (SP) having a certain tilt to the scan lines (S 1 ˜Sm), the scan data (s-data) having a certain tilt is supplied. The scan data (s-data) is gradually increased up to a certain voltage with a certain tilt. When the scan data (s-data) is gradually increased with a certain tilt, the scan pulse (SP) is gradually increased with a certain tilt. Thus, according to the equation 1, the low peak current (Lip) flows to the insulation layer 52 and a damage to the insulation layer 52 formed as a thin film can be minimized. Meanwhile, the data pulse (DP) having a certain tilt is generated in the same manner with the scan pulse (SP). FIG. 10 illustrates driving waveforms supplied to a flat type FED in accordance with a third embodiment of the present invention. As shown in FIG. 10, a square wave data pulse (DP) and scan pulse (SP) are supplied to a flat type FED in accordance with a third embodiment of the present invention. The scan data (s-data) for supplying the scan pulse (SP) makes a phase difference between the scan pulse and the data pulse. The scan data (s-data) is increased up to a certain voltage (a threshold voltage) without a tilt, and after the certain voltage is maintained for a certain time, the scan data (s-data) is increased up to a maximum voltage, that is, the sum of the voltage of the scan pulse and the voltage of the data pulse, without a tilt. Thus, two times of peak currents (Lip 1 , Lip 2 ) flow to the insulation layer 52 . Namely, when the scan data (s-data) is increased up to a certain voltage, the first peak current (LIp 1 ) flows to the insulation layer 52 . When the scan data (s-data) is maintained at a certain voltage for a certain time (a few &mgr;s), a low current flows to the insulation layer 52 . After the scan data (s-data) is maintained at a certain voltage for a certain time, when it is increased up to a certain voltage, the second peak current (LIp 2 ) flows to the insulation layer 52 . The peak currents (Lip 1 , LIp 2 ) have lower values compared to those in the conventional art, a damage to the insulation layer 52 can be minimized. FIG. 11 is a block diagram showing a driving apparatus of the flat type FED in accordance with the first through the third embodiments of the present invention. As shown in FIG. 11, a driving apparatus of the flat type FED of the present invention includes first and second data driving units 68 and 70 for supplying a data pulse (DP) to a panel 74 ; a scan driving unit 72 for supplying a scan pulse (SP) to the panel 74 ; a first frame memory 62 for storing a first data of one frame; a second frame memory 64 for storing a second data of one frame; a timing controller 66 for controlling a supply timing of the scan pulse (SP) and the data pulse (DP); and a controller 60 for controlling the timing controller 66 , the first frame memory 62 and the second frame memory 64 . The operation of the driving apparatus for generating driving waveforms in accordance with first through third embodiments of the present invention will now be described in detail. First, the controller 60 receives an image signal and a synchronous signal from an external source. The controller 60 separates first and second data from the image signal and supplies the first and second data to the first and second frame memories 62 and 64 . In addition, the controller 60 supplies the synchronous signal to the timing controller 66 . The first and second frame memories 62 and 64 temporarily store the first and second data, and supply the data of one frame as stored to the first and second data driving units 68 and 70 . Herein, the stored first and second data is data of one frame. Thereafter, the timing controller 66 supplies a first control signal to the scan driving unit 72 , and supplies a second control signal to the first and second data driving units 68 and 70 . The scan driving unit 72 receives the first control signal and sequentially supplies the scan pulse (SP) to the scan lines (S) formed at the panel 74 . The first and second data driving units 68 and 70 receive the second control signal and supply the data (that is, the data pulse) to the data line (D) formed at the panel 75 so as to be synchronized with the scan pulse (SP). Meanwhile, the scan driving unit 72 should supply the scan pulse (SP) having a certain tilt to the scan line (S), for which the scan driving unit 72 is constructed as shown in FIG. 12 . FIG. 12 is a block diagram showing the scan driving unit of FIG. 11 . As shown in FIG. 12 , the scan driving unit 72 includes: a first switching device 80 connected to a ground voltage source (GND); a second switching device 82 connected to a negative polarity (−) voltage source (−Vcc); a first pulse driving unit 76 for driving the first switching device 80 ; a second pulse driving unit 78 for driving the second switching device 82 ; a lamp pulse generator 86 installed between the second switching device 82 and the second pulse driving unit 78 and determining a timing of a pulse supplied from the second pulse driving unit 78 ; and a tilt controller 84 installed between the lamp pulse generator 86 and the second switching device 82 and determining a tilt of a pulse supplied from the lamp pulse generator 86 . The operation of the scan driving unit 72 will now be described in detail. First, the first pulse driving unit 76 receives a control signal from the timing controller 66 . Upon receipt of the control signal, the first pulse driving unit 76 generates a square wave pulse and supplies the square wave pulse to the first switching device 80 . The first switching device 80 is turned on by the square wave pulse supplied from the first pulse driving unit 76 and connects the ground voltage source (GND) and the scan line (S). Namely, when the first switching device 80 is turned on, the ground voltage is supplied to the scan line (S). The second pulse driving unit 78 receives a control signal from the timing controller 66 . Upon receipt of the control signal, the second pulse driving unit 78 generates a square wave pulse. The square wave pulse generated from the second pulse driving unit 78 is supplied to the lamp pulse generator 89 . In order to supply the driving waveforms according to the first through third embodiments of the present invention, the lamp pulse generator 89 controls a timing of the square wave pulse supplied from the second pulse driving unit 78 . For example, in order to generate the driving waveforms in accordance with the third embodiment of the present invention as shown in FIG. 10 , the square wave pulse passes up to a certain voltage, and then the square wave pulse is delayed for a certain time at the certain voltage and supplied to the tilt controller 84 . The tilt controller 84 includes an RC integrating circuit. The pulse waveform supplied from the lamp pulse generator 86 has a certain tilt by the tilt controller 84 . The pulse (that is, the scan data) having a certain tilt generated from the tilt controller 84 is supplied to the second switching device 82 . The second switching device 82 is gradually turned on by the scan data having the certain tilt supplied from the tilt controller 84 and supplies the scan pulse (SP) having a certain tilt to the scan line (S). The tilt of the scan pulse (SP) is determined by a resistance value and a capacitance value of the RC integrating circuit included in the tilt controller 84 . As so far described, the flat panel display and its driving method of the present invention has many advantages. That is, for example, first, by controlling a tilt of at least more than one pulse among the scan pulse and the data pulse, the peak current flowing to the pixel cell can be minimized. Secondly, since the minimum peak current (Lip) is repeatedly supplied to the insulation layer of the thin film, the insulation layer can be prevented from damaging. Thirdly, since the insulation layer is prevented from damaging, the life span of the flat type FED can be lengthened. Lastly, the driving drivers of the flat type FED can be prevented from damaging thanks to the minimum peak current (LIp). As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalence of such meets and bounds are therefore intended to be embraced by the appended claims.