KR20060114483A - Driving device for electron emission device and the method thereof - Google Patents

Abstract

A driving apparatus and a driving method of an electron emission device are provided to protect a panel and a driving circuit by restricting diode emission generated at the electron emission device by controlling anode voltage. A driving apparatus of an electron emission device includes a pixel unit(106); a power supply unit(103) for supplying anode power to the pixel unit, comparing an anode current value with a predetermined current value, and then outputting the compared value; and a control unit(102) for controlling the power supply unit to change the voltage level of the anode power correspondingly to the compared value output from the power supply unit. The power supply unit compares the anode current value with the predetermined current value by a comparator(101). The predetermined current value is for the peak luminance.

Description

Driving device for electron emitting device and driving method thereof {DRIVING DEVICE FOR ELECTRON EMISSION DEVICE AND THE METHOD THEREOF}

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view schematically showing the configuration of a first embodiment of a drive device for an electron-emitting device according to the invention.

FIG. 2 is a diagram schematically illustrating a configuration of the data driver of FIG. 1. FIG.

3 is a diagram schematically illustrating an example of a structure of the pixel unit of FIG. 1.

4 is a view schematically showing a configuration of a second embodiment of a drive device for an electron-emitting device according to the present invention.

<Description of main parts of drawing>

101 --- Comparators 102, 402 --- Controls

103, 403 --- power supply 104, 404 --- scan driver

105, 405 --- Data driver 106, 406 --- Pixel part

401 --- Detector 201 --- Serial to Parallel Converter

202 --- pulse width modulator 203 --- level adjuster

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for driving an electron-emitting device and a method of driving the same, and more particularly to a device for driving an electron-emitting device that can protect a panel and a driving circuit by preventing diode emission generated from the electron-emitting device. It is about.

In general, a flat panel display (FPD) is a device for manufacturing a sealed container by standing a side wall between two substrates, and placing a suitable material inside the container to display a desired screen. Together, its importance is increasing. In response to this, various flat panel displays, such as liquid crystal displays (LCDs), plasma display panels (PDPs), electron emission displays, and the like, have been developed and put into practical use.

In particular, the electron-emitting display device can be implemented as a low-power flat-panel display without distorting the image while maintaining excellent characteristics of the cathode ray tube (CRT) by using phosphor emission by electron beams in the same way as the cathode ray tube (CRT). It is attracting attention as a next-generation display that is satisfactory in terms of its large, viewing angle, high-speed response, high brightness, high definition, and thinness.

In general, an electron emission device has a method using a hot cathode and a cold cathode as an electron source. The electron-emitting devices using the cold cathode are FEA (Field Emitter Array) type, SCE (Surface Conduction Emitter) type, MIM (Metal-Insulator-Metal) type, MIS (Metal-Insulator-Semiconductor) type, BSE (Ballistic) electron surface emitting) and the like are known.

The electron emission display device has a structure of a three-pole tube having a cathode, an anode, and a gate electrode. Specifically, a cathode electrode generally used as a scan electrode is formed on a substrate, and an insulating layer having holes on the cathode electrode and a gate electrode generally used as a data electrode are stacked. An emitter, which is an electron emission source, is formed in the hole and contacts the cathode electrode.

The electron emission display device configured as described above concentrates a high electric field on an emitter and emits electrons by a quantum mechanical tunnel effect, and electrons emitted from the emitter are caused by a voltage applied between the cathode electrode and the anode electrode. By accelerating and colliding with the RGB fluorescent layer formed on the anode, the phosphor is emitted to represent an image.

As the emitted electrons collide with the fluorescent layer and the phosphor emits light, the luminance of the displayed image is changed according to the value of the input digital image signal. Specifically, the value of the digital video signal comprises 8 bits of RGB data, respectively. That is, the value of the digital video signal may be 0 (000000 ₍₂₎ ) to 255 (14111111 ₍₂₎ ), and thus 256 gray levels may be represented by 256 values. Luminance is expressed.

In order to adjust the luminance represented according to the value of the digital video signal, a pulse width modulation (PWM) method or a pulse modulation (PAM) method is generally used.

The PWM method modulates the pulse width of the driving waveform applied to the data electrode according to the digital image signal inputted from the data electrode driver, and 255 is the value of the digital image signal within the maximum available on-time. When input, the pulse width is maximized to display the maximum luminance. When 127 is input as the value of the digital video signal, the pulse width is 1/2 to adjust the luminance.

On the other hand, in the PAM method, the pulse width is constant regardless of the input digital video signal, but the luminance is controlled by changing the pulse voltage level of the driving waveform applied to the data electrode, that is, the pulse size, according to the input digital video signal.

However, in the conventional driving device of the electron-emitting device, when an overcurrent higher than the current at the peak luminance of the image level flows, the current amount increases rapidly, resulting in the damage of the driving circuit as well as the damage of the panel.

It is an object of the present invention to provide a driving apparatus and a driving method of an electron emitting device which can protect a panel and a driving circuit by preventing diode emission generated from the electron emitting device.

In order to achieve the above object, the driving device of the electron-emitting device according to the present invention includes: a pixel unit; A power supply unit supplying an anode power supply to the pixel unit, and comparing the anode current value with a predetermined current value and outputting the comparison value; And a control unit controlling the power supply unit to change the voltage level of the anode power in response to the comparison value output from the power supply unit.

In addition, the driving method of the electron-emitting device according to the present invention in order to achieve the above object, the step of receiving an image signal; Comparing an anode current value and a predetermined current value according to the brightness level of the input video signal; And receiving the compared information and controlling the anode voltage according to the comparison result.

In addition, in order to achieve the above object, the driving device of the electron-emitting device according to the present invention detects whether the video signal is input and determines that the video signal is not input. A control unit for controlling voltage and outputting a data signal as zero; A power supply unit supplying anode power at a predetermined voltage controlled by the controller; And a data driver which receives the data signal output as 0 and outputs the signal at a high level.

In addition, in order to achieve the above object, a method of driving an electron emitting device according to the present invention comprises the steps of: detecting the input of the image signal; If it is determined that the video signal is not input, outputting a data signal as 0; Outputting a data signal corresponding to the output data signal 0.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings the most preferred embodiment that can be easily carried out by those of ordinary skill in the art as follows.

1 is a view schematically showing the configuration of a first embodiment of a drive device for an electron-emitting device according to the present invention. As shown therein, the driving device of the electron-emitting device of the present invention comprises: a pixel portion 106; A power supply 103 for supplying anode power to the pixel portion 106 and comparing the anode current value with a predetermined current value and outputting the comparison value; And a controller 102 that controls the power supply 103 so that the voltage level of the anode power is changed in response to the comparison value output from the power supply 103.

In addition, the data driver 105 for receiving the signal output from the control unit 102 and pulse-width modulated the image data signal and outputs; The pixel driver 106 further includes a scan driver 104 for providing a scan electrode signal to the pixel unit 106.

The control unit 102 receives the comparison value output from the power supply unit 103, controls the anode voltage according to the comparison value, and outputs a data signal. That is, the controller 102 sets the anode voltage as a predetermined voltage when the anode current value output from the power supply unit 103 is greater than a predetermined current value. Will be reduced to voltage.

The power supply 103 performs a function of transferring the power converted from the input voltage Vin into a voltage of a predetermined level to the pixel unit 106.

More specifically, the control unit 102 receives the image level output from the controller 102 and adjusts and outputs the voltage according to the image level. That is, the power supply unit 103 is provided with a comparator 101 to always compare the current of the anode current with the peak luminance (peak) which is a predetermined current value. If the compared value is determined that the normal anode current value is greater than the peak luminance current value, the compared value is fed back to the controller 102.

Accordingly, the control unit 102 receives the compared value when the anode current is greater than the peak luminance current Ipeak in the comparator 101 so that the anode voltage is reduced to Vcutoff so that diode emission does not occur. Control.

The data driver 105 receives an image data signal from the controller 102 to perform pulse width modulation, and then adjusts and outputs a voltage level.

In the pixel unit 106, a plurality of data lines (gate electrodes or cathode electrodes) and a plurality of scan lines (gate electrodes or cathode electrodes) cross each other, and pixels (not shown) are formed at each intersection. The pixel includes a gate electrode and a cathode electrode, and receives a data signal and a scan signal through the data line and the scan line. Here, the plurality of pixel rows are sequentially selected by the scan signal input through the scan line, and the data signal is transferred to the pixel row selected by the scan signal through the data line to emit light from the pixels to form an image.

2 is a diagram schematically illustrating a configuration of the data driver of FIG. 1. As shown therein, the data driver 105 includes a serial-parallel data converter 201 which receives an image data signal input to the controller 102 and converts the image data signal into a parallel data signal; A pulse width modulator 202 which receives the parallel image data signal and the count clock converted by the serial-parallel data converter 201 and pulse-width modulates and outputs them; And a level converter 203 for adjusting and outputting a voltage level of the signal output from the pulse width modulator 202.

The serial-parallel converter 201 receives an image data signal in series from the controller 102 and converts the image data signal into a parallel signal to apply the image data signal to the data line of the pixel unit 106.

The pulse width modulator 202 generates a pulse width modulated signal by matching the parallel image data signal to a pulse width modulated frequency clock signal. That is, the controller 102 receives the converted pulse width modulation and on time based on the pulse width modulation clock conversion index and the on time conversion index generated by the controller 102, respectively.

The level converting unit 203 adjusts and outputs a voltage level of an image data signal output as a voltage forming unit for applying to the data electrode of the pixel unit 106.

Meanwhile, the scan driver 104 applies a low or high signal to each scan line (not shown) for each specific row of the pixel unit 106 to select a specific row for a predetermined period.

3 is a diagram schematically illustrating an example of a structure of the pixel unit of FIG. 1.

Referring to FIG. 2, the pixel portion 106 includes an electron emission substrate 320 and an image forming substrate 130. In addition, the spacer 340 may be further included to maintain a constant distance between the electron emission substrate 320 and the image forming substrate 330.

The electron emission substrate 320 is a substrate that emits electrons in response to the voltage between the cathode electrode 322 and the gate electrode 324. The back substrate 321, the cathode electrode 322, the insulating layer 323, and the gate are provided. The electrode 324 and the electron emission part 325 are provided.

The back substrate 321 may be, for example, a glass or silicon substrate, and a transparent substrate such as a glass substrate is preferable when the back substrate 321 is formed by back exposure using a carbon nanotube (CNT) paste as the electron emission unit 325. .

The cathode electrode 322 may be formed in a stripe shape on the rear substrate. The cathode electrode 322 is supplied with a data signal or a scan signal applied from the data driver or the scan driver. The cathode electrode 322 may be a conductor and may be a transparent conductor such as indium tin oxide (ITO), for the same reason as the back substrate 321.

The insulating layer 323 is formed on the back substrate 321 and the cathode electrode 322, and electrically insulates the cathode electrode 322 and the gate electrode 324. The insulating layer 323 may be made of an insulating material, for example, PbO and SiO ₂ mixed glass.

The gate electrode 324 is disposed on the insulating layer 323 in a predetermined shape, for example, in a direction crossing the cathode electrode 322 on a stripe, and each data signal or scan signal applied from the data driver or the scan driver. Is supplied. The gate electrode 324 is made of a conductive metal, for example, at least one conductive metal material selected from gold (Au), silver (Ag), platinum (Pt), aluminum (Al), chromium (Cr), and alloys thereof. Can be. The insulating layer 323 and the gate electrode 324 have at least one first opening 326 at the intersection of the cathode electrode 322 and the gate electrode 324 so that the cathode electrode 322 is exposed.

The electron emission unit 325 is electrically connected to and disposed on the cathode electrode 322 exposed by the first opening 326, and includes a carbon nanotube; Nanotubes by graphite, diamond, diamond-like carbon or a combination thereof; Or a nanowire of Si or SiC.

The image forming substrate 330 is a substrate for forming an image by electrons emitted from the electron emission substrate 320 colliding with each other to form an image. The front substrate 331, the anode electrode 332, the phosphor 333, and the light shielding film are formed. 334 and the metal reflective film 335.

The front substrate 331 is preferably made of a transparent material such as glass so that light emitted from the phosphor 333 is transmitted to the outside.

The anode electrode 332 is preferably made of a transparent material such as an ITO electrode so that light emitted from the phosphor 333 is transmitted to the outside. The anode electrode 332 accelerates the electrons emitted from the electron emission device even better. To this end, a high voltage positive voltage is applied to the anode electrode 332 to accelerate the electrons toward the phosphor 333.

The phosphor 333 emits light by collision of electrons emitted from the electron emission substrate 320 and is selectively disposed on the anode electrode 332 at random intervals. Examples of the G phosphor, that is, the phosphor that develops green color include, for example, ZnS: Cu, Zn ₂ SiO ₄ : Mn, ZnS: Cu + Zn ₂ SiO ₄ : Mn, Gd ₂ O ₂ S: Tb, Y ₃ Al ₅ O ₁₂ : Ce, ZnS: Cu, Al, Y ₂ O ₂ S: Tb, ZnO: Zn, ZnS: Cu, Al + In ₂ O ₃ , LaPO ₄ : Ce, Tb, BaO · 6Al ₂ O ₃ : Mn, (Zn, Cd) S: Ag, (Zn, Cd) S: Cu, Al, ZnS: Cu, Au, Al, Y ₃ (Al, Ga) ₂ O ₁₂ : Tb, Y ₂ SiO ₅ : Tb, or LaOCl: Tb Can be used. In addition, the B phosphor, i.e., a phosphor that develops blue color, may be, for example, ZnS: Ag, ZnS: Ag, Al, ZnS: Ag, Ga, Al, ZnS: Ag, Cu, Ga, Cl, ZnS: Ag + In ₂ O. ₃ , Ca ₂ B ₅ O ₉ Cl: Eu ²⁺ , (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ , Sr ₁₀ (PO ₄ ) ₆ C ₂ : Eu ²⁺ , BaMgAl ₁₆ O ₂₆ : Eu ²⁺ , CoO, Al ₂ O ₃ Added ZnS: Ag, ZnS: Ag or Ga may be used. Further, the R phosphor, i.e., the phosphor emitting red color, may be, for example, Y ₂ O ₂ S: Eu, Zn ₃ (PO ₄ ) ₂ : Mn, Y ₂ O ₃ : Eu, YVO ₄ : Eu, (Y, Gd) BO ₃ : Eu, γ-Zn ₃ (PO ₄ ) ₂ : Mn, (ZnCd) S: Ag, (ZnCd) S: Ag + In ₂ O ₃ , or Fe ₂ O ₃ added Y ₂ O ₂ S: Eu Can be used.

The light shielding film 334 is disposed at random intervals between the phosphors 333 in order to absorb and block external light and prevent optical crosstalk, thereby improving contrast ratio.

The metal reflective film is formed on the phosphor 333 to better focus electrons emitted from the electron emission substrate 320, and reflects light emitted from the phosphor 333 to the front substrate 331 by collision of electrons. To improve reflection efficiency. On the other hand, if the metal reflecting film serves as an anode electrode, the formation of the anode electrode 332 is optional and may be an unnecessary component.

In addition, according to the driving method of the first embodiment of the electron-emitting device according to the present invention, the controller 102 compares an anode current value and a predetermined current value according to a luminance level with an image signal received from the outside. Here, the predetermined current value is a peak luminance current value.

More specifically, the control unit 102 receives the image level output from the controller 102 and adjusts and outputs the voltage according to the image level. That is, the power supply unit 103 is provided with a comparator 101 so as to always compare the current of the anode current (peak) with the peak luminance (peak). If the compared value is determined that the normal anode current value is larger than the peak luminance current value, the compared value is fed back to the controller.

Then, receiving the compared information and controlling the anode voltage according to the comparison result is performed. Herein, when it is determined that the anode current is larger than the peak luminance current Ipeak in the comparator 101, the controller 102 receives the compared value and feeds back an anode voltage so that diode emission does not occur. Will be controlled by Vcutoff.

4 is a diagram schematically showing the configuration of a second embodiment of a driving device for an electron-emitting device according to the present invention. Here, a detailed description of the second embodiment of the present invention will be omitted with reference to the first embodiment.

As shown in FIG. 4, when the driving device of the electron-emitting device according to the present invention detects whether an image signal is input and determines that the image signal is not input, Vcutoff the voltage of the anode power supply. A controller 402 for controlling voltage and outputting a data signal as zero; Vcutoff controlled by the controller 402 A power supply 403 for supplying anode power at a voltage; And a data driver 405 which receives the data signal output as 0 and outputs the signal at a high level.

In addition, the pixel unit 406 for displaying the signal output from the data driver 405 as an image; The pixel driver 404 further includes a scan driver 404 for providing a scan electrode signal to the pixel unit 406.

The control unit 402 is further provided with a detection unit 401 detects the input image signal, and if it is determined that the image signal is not input, transmits 8-bit data to the data driver 405 as '0' to turn off the pixel to be turned off. That is, when the image signal is not input, diode emission may occur due to an anode voltage, so that data is output as '0' to prevent this. Here, if the output level is set to a high level when the input of the data driver 405 is '0', the output level of the data driver is output high and electrons are not emitted.

If it is determined that the video signal is not input, the control unit 402 determines that the anode voltage is Vcutoff. The voltage is controlled.

In addition, in the driving method of the first embodiment of the electron-emitting device according to the present invention, the sensing unit 401 of the control unit 402 detects whether an image signal is input.

If it is determined that the image signal is not input by the detector 401, the data signal is output as 0. That is, when no image signal comes in, the controller 402 transmits 8-bit data to the data driver 405 as '0' so that the pixel can be turned off.

The data driver 405 outputs a high level signal to the pixel unit 406 as a data signal corresponding to the data signal 0.

In addition, when it is determined that the video signal is not input, the control unit 402 Vcutoff the anode voltage. Controlled by voltage

By controlling the anode voltage in this way, diode emission can be prevented to protect the panel and drive circuitry.

Although the present invention has been described with reference to the embodiments illustrated in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

As described above, the present invention can protect the panel and the driving circuit by preventing diode emission generated from the electron-emitting device.

Claims (11)

A pixel portion; A power supply unit supplying an anode power supply to the pixel unit, and comparing the anode current value with a predetermined current value and outputting the comparison value; And a control unit for controlling the power supply unit so that the voltage level of the anode power source is changed in response to the comparison value output from the power supply unit. The method of claim 1, The power supply unit is provided with a comparator for driving the electron-emitting device for comparing the anode current value and a predetermined current value. The method of claim 1, And said predetermined current value is a current value of peak luminance. The method of claim 1, And the control unit lowers the anode voltage to a predetermined voltage when the comparison value output from the power supply unit corresponds to a value when the anode current value is greater than a predetermined current value. Receiving an image signal; Comparing an anode current value and a predetermined current value according to the brightness level of the input video signal; Receiving the compared information and controlling an anode voltage according to the comparison result. The method of claim 5, And said predetermined current value is a peak luminance current value. The method of claim 5, And a method of controlling an anode voltage when an anode current value corresponding to the brightness level is greater than a predetermined current value. If it is determined that the video signal is not input and the video signal is not input, the voltage of the anode power supply is determined. A controller for controlling voltage and outputting a data signal as zero; Predetermined controlled by the controller A power supply for supplying anode power at a voltage; And a data driver which receives the data signal output as 0 and outputs the signal at a high level. The method of claim 8, The controller of claim 1, wherein the control unit includes a sensing unit for detecting whether an image signal is input. Detecting whether an image signal is input; If it is determined that the video signal is not input, outputting a data signal as 0; And outputting a data signal corresponding to the output data signal 0. The method of claim 10, When it is determined that the video signal is not input, Vcutoff the anode voltage. A method of driving an electron-emitting device controlled by voltage.

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