Driving apparatus of electroluminescent display device and driving method thereof

• US 20030034939A1
• Filed: 08/09/2002
• Published: 02/20/2003
• Est. Priority Date: 08/17/2001
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Moon, Seong Hak
• Granted Patent: US 7,119,770 B2
• Time in Patent Office: Days
• US Class Current: 345/76
• CPC Class Codes: G09G 2310/0254 Control of polarity reversal in general, other than for liquid crystal displays
• CPC Class Codes: G09G 2310/0267 Details of drivers for scan electrodes, other than drivers for liquid crystal, plasma or OLED displays
• CPC Class Codes: G09G 2310/0275 Details of drivers for data electrodes, other than drivers for liquid crystal, plasma or OLED displays, not related to handling digital grey scale data or to communication of data to the pixels by means of a current
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/30 using electroluminescent panels

Abstract

A driving apparatus of an electroluminescent display device includes: a scan driving unit for receiving a voltage from a single voltage source and sequentially supplying a scan pulse of which polarity is reversed by the frame unit to scan lines; and a data driving unit for receiving the voltage and sequentially supplying a data pulse with an opposite polarity to the polarity of the scan pulse to data lines. An optimum voltage to a pixel cell can be supplied by completely removing electric charges charged in the pixel cell by reversing a positive pulse or a negative pulse generated by a single power source by the frame unit and supplying it to each data line and scan line.

Claims

1. A driving apparatus of an electroluminescent display device comprising:

a plurality of pixel cells formed between a plurality of scan lines and data lines;

a scan driving unit for receiving a voltage from a single scan voltage source and sequentially supplying a scan pulse of which a polarity has been reversed by a certain unit to the scan lines; and

a data driving unit for receiving a voltage from a single data voltage source and supplying a data pulse to the data lines.

2. The apparatus of claim 1, wherein the scan driving unit comprises:

a scan pulse generator for charging a voltage inputted from the single scan voltage source, reversing a polarity of the charged voltage by a certain unit and switching it to have a first or a second polarity; and

a scan drive IC (Integrated Circuit) for sequentially supplying a scan pulse with a first or a second polarity to the scan lines.

3. The apparatus of claim 2, wherein the scan pulse generator comprises:

a first capacitor for charging an inputted voltage;

a first switching device installed between the single scan voltage source and a first terminal of the first capacitor and switching the voltage supplied from the single scan voltage source so as to be charged in the first capacitor;

a second switching device installed between the first terminal of the first capacitor and a ground voltage source and grounding the first capacitor to the ground voltage source; and

a third switching device installed between a second terminal of the first capacitor and the ground voltage source and floating a voltage of th second terminal of the first capacitor.

4. The apparatus of claim 2, wherein the scan drive IC receives the scan pulse charged in the first capacitor and sequentially applies it to each scan line.

5. The apparatus of claim 1, wherein the data driving unit comprises:

a data pulse generator for charging the voltage inputted from the single data voltage source, reversing a polarity of the charged voltage by a certain unit so as to have a voltage with a first or a second polarity; and

a data drive IC for supplying the data pulse with the first or the second polarity to the data lines.

6. The apparatus of claim 5, wherein the data pulse generator comprises:

a second capacitor for charging the voltage inputted from the single data voltage source;

a fourth switching device installed between the single data voltage source and a first terminal of the second capacitor and switching the voltage supplied from the single voltage source so as to be charged in the second capacitor;

a fifth switching device installed between the first terminal of the second capacitor and a ground voltage source and grounding the second capacitor to the ground voltage source; and

a sixth switching device installed between a second terminal of the second capacitor and floating a voltage of the second terminal of the second capacitor.

7. The apparatus of claim 5, wherein the data drive IC receives a data pulse charged in the second capacitor and applies it to each data line.

8. The apparatus of claim 1, wherein a doubler circuit for doubling the voltage of the single scan voltage source is installed between the single scan voltage source and the scan pulse generator.

9. The apparatus of claim 8, wherein the doubler circuit comprises:

a third capacitor for charging the voltage supplied from the single scan voltage source;

a seventh switching device installed between the third capacitor and the ground voltage source and switching the voltage supplied from the single low voltage source so as to be charged in the third capacitor;

an eighth switching device installed between the third capacitor and the single voltage source and doubling the voltage charged in the third capacitor by integer times; and

a first diode installed between the third capacitor and the single voltage source and cutting off a reverse voltage flowing to the single low voltage source.

10. The apparatus of claim 1, wherein a doubler circuit for doubling the voltage of the single data voltage source by integer times is installed between the single data voltage source and the data pulse generating unit.

11. The apparatus of claim 10, wherein the doubler circuit comprises:

a fourth capacitor for charging the voltage supplied from the single data voltage source;

a ninth switching device installed between the fourth capacitor and the ground voltage source and switched so that the voltage supplied from the single low voltage source can be charged in the fourth capacitor;

a tenth switching device installed between the fourth capacitor and the single voltage source and switching the voltage charged in the fourth capacitor so as to be doubled by integer times; and

a second diode installed between the third capacitor and the single voltage source and cutting off a reverse voltage flowing to the single low voltage source.

12. The apparatus of claim 2, wherein the scan pulse generator reverses a polarity of the voltage charged in the first capacitor by the unit of field, frame and/or line.

13. The apparatus of claim 12, wherein in case that the scan voltage is reversed by the line unit and supplied to the scan line, the scan driving unit is constructed by being divided into odd line scan driving units and even line scan driving units formed at both sides of a panel.

14. The apparatus of claim 13, wherein the data driving unit is constructed by being divided into odd line data driving units and even line data driving units formed at each panel, in order to supply a data pulse with the opposite polarity to the scan pulse.

15. The apparatus of claim 13, wherein the scan driving unit is controlled so that the a polarity of the scan pulse is reversed at every line and the size of the scan pulse is different for every frame.

16. The apparatus of claim 15, wherein the scan driving unit comprises:

a doubler circuit for doubling the voltage of the single voltage source by integer times;

a fifth capacitor for charging the voltage supplied directly from the doubler circuit or the single scan voltage source;

a scan pulse generator including a switching device for reversing a polarity of the voltage charged in the fifth capacitor and generating scan pulses with mutually different levels; and

a scan driving IC for receiving the generated scan pulses and supplying the scan pulses with mutually different polarity and level to the odd scan lines and even scan lines.

17. The apparatus of claim 16, wherein the doubler circuit comprises:

a sixth capacitor for charging the voltage supplied from the single scan voltage source;

an eleventh switching device installed between the sixth capacitor and the ground voltage source and switched so that the voltage supplied from the single voltage source can be charged in the sixth capacitor;

a twelfth switching device installed between the sixth capacitor and the single voltage source and doubling the voltage charged in the sixth capacitor by integer times; and

a third diode installed between the sixth capacitor and the single voltage source and cutting a reverse voltage flowing to the single low voltage source.

18. The apparatus of claim 17, wherein the switching device of the scan pulse generating unit comprises:

a thirteenth switching device connecting a first terminal of the fifth capacitor and a second terminal of the sixth capacitor; and

a fourteenth switching device connected between a second terminal of the fifth capacitor and a ground voltage.

19. The apparatus of claim 16, wherein the data driving unit is constructed by being divided into odd line data driving units and even line data driving units formed at an upper side and a lower side of a panel, in order to supply the data pulse to the data line.

20. The apparatus of claim 19, wherein the data driving unit comprises:

a data driving unit;

a doubler circuit for doubling the voltage inputted from the single voltage source; and

a data driving IC for applying the doubled voltage to the data line so as to have the same polarity all the time.

21. The apparatus of claim 2, wherein the scan driving unit is controlled so that the polarity of the scan pulse is reversed and the size of the scan pulse is different for every red, green and blue data.

22. The apparatus of claim 21, wherein the scan driving unit is divided into a red and green line scan driving unit and a blue line scan driving unit formed at both sides of each panel.

23. The apparatus of claim 22, wherein each scan driving unit comprises:

a doubler circuit for doubling the voltage inputted from each single scan voltage source by integer times;

a scan pulse generator for charging the voltage supplied from the doubler circuit or the single voltage source, and reversing a polarity of the charged voltage to generate scan voltages with mutually different levels; and

a scan driving IC for supplying the generated scan pulse to the red, green and blue scan lines so that each line has mutually different polarity and level.

24. The apparatus of claim 23, wherein the doubler circuit comprises:

a seventh capacitor for charging the voltage applied from the single scan voltage source;

a fifteenth switching device installed between the seventh capacitor and the ground voltage source and switching the voltage supplied from the single voltage source so as to be charged in the seventh capacitor;

a sixteenth switching device installed between the seventh capacitor and doubling the voltage charged in the seventh capacitor by integer times; and

a fourth diode installed between the seventh capacitor and the single voltage source and cutting off a reverse voltage flowing to the single low voltage source.

25. The apparatus of claim 24, wherein the scan pulse generator comprises:

an eighth capacitor for charging the voltage supplied from the doubler circuit;

a seventeenth switching device for connecting a first terminal of the eighth capacitor and a second terminal of the seventh capacitor; and

an eighteenth switching device connected between a second terminal of the eighth capacitor and the ground voltage source.

26. The apparatus of claim 21, wherein the data driving unit is constructed by being divided into a red and green line data driving units and a blue line data driving unit formed at an upper side and a lower side of each panel, in order to supply the data pulse to the data line.

27. The apparatus of claim 26, wherein the data driving unit comprises:

a doubler circuit for doubling the voltage of the single voltage source by integer times;

a ninth capacitor for charging the voltage supplied from the ninth capacitor;

a data pulse generator including a switching for reversing a polarity of the voltage charged in the ninth capacitor and generating a data voltage; and

a data driving IC for supplying the scan pulses with mutually different polarities as generated to the red, green and blue data lines.

28. The apparatus of claim 27, wherein the doubler circuit comprises:

a tenth capacitor for charging the voltage supplied from the single voltage source;

a nineteenth switching device installed between the tenth capacitor and the ground voltage source and switched so that the voltage supplied from the single voltage source can be charged in the tenth capacitor;

a twentieth switching device installed between the tenth capacitor and switched so that the voltage charged in the tenth capacitor can be doubled by integer times; and

a fifth diode installed between the tenth capacitor and the single voltage source and cutting off a reverse voltage flowing to the single low voltage source.

29. The apparatus of claim 17, wherein the switching device of the data pulse generator comprises:

a nineteenth switching device for connecting a first terminal of the ninth capacitor and a second terminal of the tenth capacitor; and

a twenty-first switching device connected between a second terminal of the ninth capacitance and the ground voltage.

30. The apparatus of claim 2, wherein the data driving unit is constructed by being divided in a red data driving unit, green data driving unit and a blue data driving unit each having a voltage source with mutually different driving voltage by red, green and blue data.

31. The apparatus of claim 30, each of the red, green and blue data driving units comprises:

a doubler circuit for receiving a voltage from the single voltage source and doubling it;

a data pulse generator for charging the voltage supplied from the doubler circuit, and reversing a polarity of the charged voltage to generate a data pulse so as to have the opposite polarity by lines and have mutually different data voltage for the red, green and blue data; and

a data driving IC for supplying the generated data pulse to each of the red, green and blue data line.

32. The apparatus of claim 30, wherein the data pulse is pulse-width modulated.