KR100456138B1 - Apparatus and Method for Driving of Metal Insulator Metal Field Emission Display - Google Patents

Abstract

The present invention relates to a driving apparatus and method for a flat field emission display device capable of improving cell uniformity.

The apparatus and method for driving the planar field emission display device in the method for driving a planar field emission display device using a scan pulse supply unit for generating a scan pulse and a scan drive IC connected between the scan pulse supply unit and a plurality of scan lines is provided. And after generating a pseudo pulse in the scan pulse supply unit, a plurality of scan pulses are continuously generated in the scan pulse supply unit following the pseudo pulse, and scanning the scan lines to be synchronized with video data through the scan drive IC. The pulses are supplied sequentially.

Description

Apparatus and Method for Driving of Metal Insulator Metal Field Emission Display}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel display panel and a driving method, and more particularly, to a driving device and method for a flat field emission display device capable of improving cell uniformity.

Recently, various flat panel displays have been developed to reduce weight and volume, which are disadvantages of cathode ray tubes. Such flat panel displays include liquid crystal displays, field emission displays (hereinafter referred to as "FEDs"), plasma display panels, and electroluminescence (Electro-Luminescence). Etc. In order to improve the display quality, research and development are being actively conducted to increase the brightness, contrast, and color purity of flat panel displays.

The FED displays an image using light generated by colliding electrons emitted from the field emission display device with the phosphor. The field emission display device used in such an FED includes a tip type (FE type), a flat type (MIM type or MIS type), or a surface conduction type (SCE type).

In the FE type field emission display device, a voltage is applied to a gate electrode to apply an electric field to an electron emission portion, thereby emitting electrons from a cone-shaped protrusion made of silicon (Si) or molybdenum (Mo). In a MIM type or MIS type field emission display device, a stacked structure including a metal, an insulator layer, a semiconductor layer, etc. is formed, and electrons are injected from the metal layer side into the insulator layer using a tunnel effect. Pass through and withdraw from the electron-emitting part to the outside. In addition, in the SCE type field emission display device, current flows in the in-plane direction of a thin film formed on a substrate, thereby emitting electrons from a previously formed electron emission portion (generally, a minute crack portion present in the conduction region of the thin film).

However, the conventional FED requires a high voltage because the voltage applied between the gate (data) and the scan electrode is about tens of volts to about 100V, and the voltage applied depends on the gate hole diameter in the FE type. On the other hand, the MIM type can be driven at a low voltage because only a few V is applied at a very low voltage from the conventional V, and electrons are emitted in a straight line.

Accordingly, in recent years, field emission displays using MIM type instead of FE type have been studied.

1 is a cross-sectional view illustrating a pixel cell of a MIM type field emission display device.

Referring to FIG. 1, a pixel cell of a MIM type FED includes an upper substrate 2 on which an anode electrode 6 and a phosphor 12 are stacked, and a field emission array 16 formed on the lower substrate 4. do.

The field emission array 16 includes a scan electrode 10 formed on the lower substrate 4, an insulator layer 14 formed on the scan electrode 10, and a data electrode formed on the insulator layer 14. 8). The scan electrode 10 supplies current to the insulator layer 14, and the insulator layer 14 insulates between the scan electrode 10 and the data electrode 8, and the data electrode 8 draws electrons. It is used as an extraction electrode to make. In addition, the scan electrode 10 receives a scan pulse from a scan driver (not shown), and the data electrode 8 receives a data pulse from a data driver (not shown).

In order to display an image, a positive voltage is applied to the anode electrode 6 on the upper substrate 2. A negative voltage (−) is applied to the scan electrode 10 on the lower substrate 4, and a positive voltage (+) is applied to the data electrode 8. Then, some electrons of the scan electrode 10 tunnel the insulating layer 14, and electrons having high energy are emitted through the insulating layer 14 and the data electrode 8 into the vacuum. The emitted electrons collide with the phosphor 12 of red (R), green (G), and blue (B) to excite the phosphor 12. At this time, visible light of any one of red (R), green (G), and blue (B) is generated according to the phosphor 12.

FIG. 2 is a waveform diagram showing a driving waveform of the MIM type FED shown in FIG. 1.

2, negative scan pulses SP are sequentially supplied to scan electrodes S of a conventional FED, and positive polarities are synchronized to negative scan pulses SP to data electrodes D. FIG. The data pulse DP is supplied. In the pixel cells supplied with the scan pulse SP and the data pulse DP, electrons are emitted by the voltage difference between the scan pulse SP and the data pulse DP. For example, when -5V scan pulse SP is applied to the first scan electrode S1 and 5V data pulse DP is applied to the data electrode D, the scan pulse SP is formed on the first scan electrode S1. A voltage difference of 10V is generated in the first pixel cells P1. Therefore, electrons are emitted from the first pixel cells P1 supplied with the data pulse DP.

FIG. 3 is a block diagram illustrating driving units for generating a driving waveform shown in FIG. 2.

Referring to FIG. 3, the driving unit scans to sequentially select a scan pulse supply unit 20 for generating scan pulses and scan lines S1 to Sm to which scan pulses supplied from the scan pulse supply unit 20 are supplied. The drive IC 22 is provided.

The scan pulse supply unit 20 includes first and second switches SW1 and SW2 installed in parallel between the ground potential GND and the scan drive IC 22, the scan pulse voltage source Vs and the scan drive IC 22. ) Is further provided with a third switch SW3 provided between the third switch SW3 and a fourth switch SW4 provided between the reset pulse voltage source Vr and the scan drive IC 22.

The first to fourth switches SW1 to SW4 are turned on / off in response to a control signal supplied from a timing controller (not shown).

The first switch SW1 and the third switch SW3 supply the scan pulse SP to the corresponding scan lines S1 to Sm in response to a control signal supplied from a timing controller (not shown). The second switch SW2 and the fourth switch SW4 supply the reset pulse RP to all the scan lines S1 to Sm in response to a control signal supplied from a timing controller (not shown). The first switch SW1 serves to raise the negative scan pulse SP to the ground potential GND, and the third switch SW3 serves to supply the negative scan pulse SP. The second switch SW2 maintains the off state while the scan pulse SP and the reset pulse RP are generated, and after the reset pulse RP is supplied to the scan lines S1 to Sm, the scan lines S It is turned on after the reset pulse RP is generated to lower the voltage of S1 to Sm to the ground potential GND. The fourth switch 61 serves to supply the reset pulse RP to all scan lines S1 to Sm.

The operation of such a driving unit will be described with reference to FIG. 4 as follows. Referring to FIG. 4, when the first, second, and fourth switches SW1, SW2, and SW4 remain in an off state, when the third switch SW3 is turned on, the scan is negative from the scan pulse voltage source Vs. The pulse SP is supplied to the first scan line SW1 selected by the scan drive IC 22. The data pulse DP is supplied to the data electrodes D1 to Dn in synchronization with the negative scan pulse SP. Thereafter, while the third switch SW3 is turned off, the first switch SW1 is turned on. At this time, the voltage of the first scan line S1 rises to the ground potential GND.

Next, when the second scan line S2 is selected from the scan pulse supply unit 20 and the third switch SW3 is turned on, the scan pulse SP that is negative from the scan pulse voltage source Vs is scanned second. It is supplied to the line S2. The data pulse DP is supplied to the data electrodes D1 to Dn in synchronization with the negative scan pulse SP.

In this way, the scan pulse SP is sequentially supplied to all the scan lines S1 to Sm by switching between the first and third switches SW1 and SW3.

When the scan pulse SP is supplied to all the scan lines S1 to Sm, when the fourth switch SW4 is turned on while the second switch SW2 is turned off, the positive pulse is reset from the reset pulse supply Vr. The pulses are simultaneously supplied with the reset pulse SP to all the scan lines S1 to Sm.

FIG. 5 compares the output Vsus of the scan pulse supply unit 20 and the waveforms supplied to the scan lines S1 to Sm. Referring to FIG. 5, the period of the output Vsus of the scan pulse supply unit 20 is illustrated. The negative scan pulse SP is sequentially supplied to all the scan lines S1 to Sm by the negative voltage. At this time, the waveform of the scan pulse SP is distorted in the first scan line S1. Accordingly, the screen of the FED may have a difference in brightness between the first scan line S1 and the other scan lines S2 to Sm as shown in FIG. 6.

In FIG. 6, the first scan line S1 is darker than other second to nth scan lines S2 to Sm due to the waveform distortion A of the scan pulse SP.

Referring to FIG. 7, capacitors C1 to Cn representing equivalent cells of the FED and pull-up resistors R connected to the scan drive IC 22 are shown.

The scan pulse distortion A in the first scan line S1 is output of the scan drive IC 22 and the output Vsus of the scan pulse supply unit 20 when the scan pulse is supplied to the first scan line S1. It is caused by impedance mismatch between. In detail, as shown in FIG. 5, before the scan pulse SP is supplied to the first scan line S1, the output Vsus of the scan pulse supply unit 20 maintains a constant 0V. In this initial state, when the output Vsus of the scan pulse supply unit 20 changes to -5V, the scan pulse supply unit 20 and the scan drive IC 22 are connected, and the output current of the scan drive IC 22 changes rapidly. When the scan pulse SP starts to be supplied to one scan line S1, an impedance mismatch is established between the output of the scan pulse supply unit 20 and the output of the scan drive IC 22, and the capacitor C of the cell and The pull-up resistor R acts as a load so that the voltage of the first scan line S1 is distorted. Unlike this, before the scan pulse SP is supplied to the scan lines S2 to Sm other than the first scan line S1, the scan is performed while the output Vsus of the scan pulse supply unit 20 is maintained at −5 V. Since the pulse supply unit 20 and the scan drive IC 22 are connected, the impedance substantially matches between the output Vsus of the scan pulse supply unit 20 and the output of the scan drive IC 22 as shown in FIG. 5. In this state, the scan pulse SP is supplied to the respective scan lines S2 to Sm. Therefore, the scan pulses SP supplied to the scan lines S2 to Sm other than the first scan line S1 have waveform distortions compared to the first scan pulses SP supplied to the first scan line S1. There is almost no. The luminance of the cells connected to the first scan line S1 is lower than that of the cells connected to the other scan lines S2 to Sm by the first scan pulse SP.

Accordingly, it is an object of the present invention to provide a driving device and method for a flat field emission display device capable of improving cell uniformity.

1 is a cross-sectional view showing a pixel cell of a MIM type field emission display device.

FIG. 2 is a waveform diagram illustrating a method of driving the field emission display device illustrated in FIG. 1.

3 is a circuit diagram illustrating a driving circuit for driving the scan electrode shown in FIG. 1.

4 is a drive timing diagram for generating a drive waveform diagram and a drive waveform diagram of the drive circuit shown in FIG.

FIG. 5 is a waveform diagram illustrating waveform distortion occurring in a conventional first scan line; FIG.

FIG. 6 is a diagram illustrating a difference in brightness of a screen according to waveform distortion shown in FIG. 5.

7 is a circuit diagram showing an equivalent circuit of a scan electrode and a data electrode.

8 is a circuit diagram showing a driving circuit for driving a scan electrode according to the present invention.

FIG. 9 is a timing diagram for generating a drive waveform diagram and a drive waveform diagram of the drive circuit shown in FIG. 8; FIG.

10 is a waveform diagram illustrating scan pulses supplied to a scan electrode according to the present invention;

<Explanation of symbols for main parts of drawing>

2: upper substrate 4: lower substrate

6: anode electrode 8: data electrode

10 scanning electrode 12 phosphor

14: insulator layer 16; Field emission array

20, 42: scan pulse supply unit 22, 70: scan driver integrated circuit

40: scan line selector 41: data driver

54,55,56,57: drive integrated circuit 58,59,60,61: switch

62: timing control unit 64, 68: first and second buffers

In order to achieve the above object, the driving method of the planar field emission display device according to the present invention is a planar electric field using a scan pulse supply unit generating a scan pulse and a scan drive IC connected between the scan pulse supply unit and a plurality of scan lines A driving method of an emission display device, comprising: generating a pseudo pulse at the scan pulse supply unit; Continuously generating a plurality of scan pulses following the pseudo pulses at the scan pulse supply unit; And sequentially supplying the scan pulses to the scan lines so as to be synchronized with the video data through the scan drive IC. The method of driving the planar field emission display device may include the pseudo pulses being the first of the scan lines. And supplying the first scan line to which the scan pulses are applied. The driving device of the planar field emission display device according to an exemplary embodiment of the present invention includes a plurality of scan pulses continuously generating a plurality of scan pulses after generating a pseudo pulse. A supply unit; And a scan drive IC connected to an output terminal of the scan pulse generator and a plurality of scan lines and sequentially supplying the scan pulses to the scan lines so as to be synchronized with video data. The first scan pulse is supplied to the first scan line to which the first scan pulse is applied.

Other objects and features of the present invention in addition to the above objects will become apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 8 to 10.

Referring to FIG. 8, the driving unit of the flat panel display panel according to the present invention selects the data driver 41 for supplying data to the data lines D and the scan line S to which the scan pulse SP is to be supplied. And a scan pulse supply unit 42 for supplying a scan pulse SP to the scan line S selected by the scan line selector 40.

The data driver 41 supplies data pulses to the data lines D1 to Dn depending on whether data is supplied or not.

The scan line selector 40 includes a timing controller 62 for supplying scan data according to the supply timing of the scan pulse SP, a first buffer 64 for temporarily storing the scan data, and a first buffer ( Photo coupler 66 for electrically insulating 64 and second buffer 68, second buffer 68 for temporarily storing data supplied from photo coupler 66, and second buffer 68 A scan drive IC 70 may be provided to receive scan data from the scan data and to sequentially supply scan pulses SP to the scan electrodes S1 to Sm.

The first stages of the timing controller 62, the first buffer 64, and the photo coupler 66 are connected to the ground potential GND. The photo coupler 66, the second buffer 68, and the scan drive IC 70 are supplied with a negative voltage from the fixed voltage source Vss.

The timing controller 62 supplies the scan data to the first buffer 64 at a predetermined interval so that the scan pulse SP can be sequentially supplied to the scan electrodes S1 to Sm. The first buffer 64 temporarily stores the scan data and supplies the stored data to the porter coupler 66. The photo coupler 66 supplies the data supplied from the first buffer 64 to the second buffer 68. In addition, the timing controller 62 generates a switching control signal for controlling the switches of the scan pulse supply unit 42.

The second buffer 68 temporarily stores the scan data supplied from the photo coupler 66 and supplies the stored data to the scan drive IC 70. The scan drive IC 70 includes a plurality of switching elements, and any one switch element is turned on by scan data supplied from the second buffer 68 to scan the scan pulse SP to the scan electrodes S1. To Sm). On the other hand, a shift register (not shown) may be further provided between the second buffer 68 and the scan drive IC 70. The shift register sequentially drives a plurality of switches included in the scan drive IC 70.

The scan pulse supply unit 42 supplies the scan pulse SP to the scan lines S1 to Sm selected by the scan line selector 40. To this end, the scan pulse supply unit 42 includes first and second switches 58 and 59 which are installed in parallel between the ground potential GND and the first contact point N1, and the scan pulse voltage source Vs and the first contact point. Third switch 60 provided between (N1), the fourth switch 61 provided between the reset pulse voltage source (Vr) and the first contact (N1), and the first to fourth switches (58, 59) First and fourth drive ICs 54, 55, 56, and 57 for driving the first and fourth drive ICs 60, 61, respectively.

The first drive IC 54 drives the first switch 58 in response to a control signal supplied from the timing controller 62. The second drive IC 55 drives the second switch 59 in response to a control signal supplied from the timing controller 62. The third drive IC 56 drives the third switch 60 in response to a control signal supplied from the timing controller 62. The fourth drive IC 57 drives the fourth switch 61 in response to a control signal supplied from the timing controller 62.

The first switch 58 and the third switch 60 respectively supply scan pulses SP to corresponding scan lines S1 to Sm in response to driving signals of the first and third drive ICs 54 and 56, respectively. do. The second switch 59 and the fourth switch 61 supply reset pulses RP to the corresponding scan lines S1 to Sm in response to driving signals of the second and fourth drive ICs 55 and 57, respectively. do. At this time, the first switch 58 serves to raise the negative scan pulse SP to the ground potential GND as the P-type transistor, and the third switch 60 is the negative scan pulse as the N-type transistor. (SP) serves to supply. The second switch 59 maintains the off state while the scan pulse SP and the reset pulse RP are supplied, and immediately after the reset pulse RP is supplied to the scan lines S1 through Sm. It is turned on to lower the voltage of Sm). The fourth switch 61 serves as a P-type transistor to supply the reset pulse RP to each scan line S1 to Sm.

9 and 10 will be described below. Referring to FIGS. 9 and 10, the scan pulse supply unit 42 applies the scan pulse SP to the first scan line S1. Before supplying, a Pseduo Pulse PP of -5V is output under the control of the timing controller 62.

The pseudo pulse PP is supplied with the first scan pulse SP by setting the output Vsus of the scan pulse supply unit 42 to -5V in advance as the scan pulse SP before the first scan pulse SP is output. The impedance between the output of the scan pulse supply 42 and the output of the scan drive IC 70. In contrast, in the prior art without the pseudo pulse PP as shown in FIG. 5, since the output Vsus of the scan pulse supply unit is 0 V before the first scan pulse is generated, the first scan pulse is the first scan line S1. Impedance mismatching occurs between the output Vsus of the scan pulse supply unit and the output of the scan drive IC 70 when the power supply is started. It is generated by turning on the third switch 60 with the one, two and four switches 58, 59 and 61 turned off. This pseudo pulse PP is supplied by the scan drive IC 70 before the first scan pulse SP is supplied to the first scan line S1 as described above. When the pseudo pulse PP is supplied, the pseudo pulse PP may be distorted like the first scan pulse of the related art, but the pseudo pulse PP may have the first scan pulse SP having the first scan line S1. It does not affect the quality at all since it occurs before it is supplied.

Next, in the other scan lines S2 to Sm, the scan pulses are supplied while the impedances are already matched between the output Vsus of the scan pulse supply unit 42 and the output of the scan drive IC 70. There is little distortion.

The scan pulses SP supplied to the scan lines S2 to Sm other than the first scan line S1 are switched between the first and third switches 58 and 60 under the control of the timing controller 62. It is generated according to the operation. The data pulse DP is supplied to the data electrode D in synchronization with the scan pulses SP.

When the third switch 60 is turned off and the first switch 58 is turned on, the voltage of the scan lines S1 to Sm whose voltage is lowered by the scan pulse SP rises to the ground potential GND.

When the scan pulse SP is supplied to all the scan lines S1 to Sm, the positive reset pulse RP is simultaneously supplied to all the scan lines S1 to Sm by the turn-on of the fourth switch 61. As a result, the apparatus and method for driving a flat panel display panel according to the present invention causes the pseudo pulse PP of -5 V to be output from the scan pulse supply 42 before the first scan pulse SP is generated. When the first scan pulse SP is supplied, the impedance is matched between the output Vsus of the scan pulse supply 42 and the output of the scan drive IC 70 and then the output current of the scan drive IC 70 is adjusted. Prevent sudden changes.

As described above, the apparatus and method for driving a flat panel display panel according to the present invention match the output impedance of the scan pulse supply unit with the output impedance of the scan drive IC before the first scan pulse is supplied to the first scan line. The distortion of the scan pulse waveform can be minimized. As a result, brightness of the first scan line is prevented from being lowered, thereby making the brightness of the entire screen uniform.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (4)

In a driving method of a flat field emission display device using a scan pulse supply unit for generating a scan pulse and a scan drive IC connected between the scan pulse supply unit and a plurality of scan lines, Generating a pseudo pulse from the scan pulse supply unit; Continuously generating a plurality of scan pulses following the pseudo pulses at the scan pulse supply unit; And sequentially supplying the scan pulses to the scan lines so as to be synchronized with the video data through the scan drive IC. The method of claim 1, And supplying the pseudo pulses to a first scan line to which a first scan pulse is applied among the scan lines. A scan pulse supply unit for generating a plurality of scan pulses continuously after generating a pseudo pulse; And a scan drive IC which is connected between the output terminal of the scan pulse generator and the plurality of scan lines and sequentially supplies the scan pulses to the scan lines so as to be synchronized with video data of the planar field emission display device. Drive system. The method of claim 3, wherein And the scan drive IC supplies the pseudo pulse to a first scan line to which the first scan pulse is applied.