Display device and associated drive control method

• US 20050280613A1
• Filed: 06/16/2005
• Published: 12/22/2005
• Est. Priority Date: 06/18/2004
• Status: Active Grant

• Current Assignee: Solas OLED Limited (Atlantic IP Services Limited)
• Original Assignee: Casio Computer Company Limited
• Inventors: Yamaguchi, Ikuhiro, Shirasaki, Tomoyuki, Ozaki, Tsuyoshi, Ogura, Jun, Takei, Manabu
• Granted Patent: US 7,898,507 B2
• Time in Patent Office: Days
• US Class Current: 345/76
• CPC Class Codes: G09G 2300/0819 used for counteracting undesired variations, e.g. feedback or autozeroing
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0866 by means of changes in the pixel supply voltage
• CPC Class Codes: G09G 2310/0216 Interleaved control phases for different scan lines in the same sub-field, e.g. initialization, addressing and sustaining in plasma displays that are not simultaneous for all scan lines
• CPC Class Codes: G09G 2310/0248 Precharge or discharge of column electrodes before or after applying exact column voltages
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• CPC Class Codes: G09G 3/325 the data current flowing through the driving transistor during a setting phase, e.g. by using a switch for connecting the driving transistor to the data driver
• CPC Class Codes: G09G 3/3266 Details of drivers for scan electrodes
• CPC Class Codes: G09G 3/3283 in which the data driver supplies a variable data current for setting the current through, or the voltage across, the light-emitting elements

Abstract

A display device which displays image information based on display data comprising a display panel having a plurality of signal lines and scanning lines with a plurality of display pixels containing current control type light emitting devices; a scan driver circuit applies a scanning signal to each of the scanning lines and sets the display pixels connected to the scanning lines in a selective state; a signal driver circuit generates gradation current based on the display data luminosity gradation component and supplies to the display pixels set in the selective state; a precharge circuit applies a precharge voltage to each signal line and sets a capacity component attached to each of the scanning lines in a predetermined charged state; and an operation control circuit controls setting of the light emitting devices in a non-light emitting state when the capacity component is set in a predetermined charged state.

Claims

1. A display device which displays image information based on display data comprising at least:

a display panel which has a plurality of signal lines and a plurality of scanning lines situated in directions to mutually intersect and a plurality of display pixels containing current control type light emitting devices positioned near each intersecting point of those plurality of signal lines and plurality of scanning lines;

a scan driver circuit which applies a scanning signal to each of the plurality of scanning lines and sets the display pixels connected to the scanning lines in a selective state;

a signal driver circuit which generates gradation current based on the display data luminosity gradation component and supplies to the display pixels set in the selective state by the scan driver circuit via each of the signal lines;

a precharge circuit which applies a precharge voltage to each of the plurality of signal lines and sets a capacity component attached to each of the signal lines in a predetermined charged state; and

an operation control circuit which controls setting of the light emitting devices in a non-light emitting state when the capacity component is set in a predetermined charged state by the precharge circuit.

2. The display device according to claim 1, wherein the operation control circuit sets the light emitting devices in a non-light emitting state when the gradation current is supplied to the display pixels by the signal driver circuit and during which an electric charge is stored based on the gradation current in the display pixels, sets the display pixels in a non-selective state by the scan driver and sets the light emitting devices in a state which performs a light emitting operation based on the electric charge stored in the display pixels.

3. The display device according to claim 1, wherein the capacity component includes a capacitor formed within the wiring between the signal lines and the scanning lines.

4. The display device according to claim 1, wherein the display pixels comprise a light emitting driver circuit comprising a storage capacitor which stores an electric charge based on the gradation current as a voltage component and a drive current control circuit comprising an active device which flows light emitting drive current to the light emitting devices for performing a light emitting operation based on a voltage component stored in the storage capacitor.

5. The display device according to claim 4, wherein the capacity component includes a capacitor formed within the wiring between the signal lines and the scanning lines, as well as the storage capacitor.

6. The display device according to claim 4, wherein the precharge voltage sets the light emitting devices provided in the display pixels based on voltage charged in the storage capacitor for performing a light emitting operation at a specified luminosity gradation.

7. The display device according to claim 6, wherein the specified luminosity gradation constitutes the lowest gradation in a range of luminance gradations.

8. The display device according to claim 4, wherein the precharge voltage sets voltage charged in the storage capacitor so as to constitute voltage which does not cause an “

ON”

state in the active device formed in the drive current control circuit.

9. The display device according to claim 1, wherein the precharge circuit comprises a switching circuit which simultaneously applies the precharge voltage to all the signal lines situated in the display panel.

10. The display device according to claim 1, wherein the scan driver circuit generates and outputs a precharge control signal which controls the precharge circuit operating state.

11. The display device according to claim 1, wherein the operation control circuit controls setting of the display pixels i n a non-selective state by the scan driver circuit when the capacity component is set in a predetermined charged state by the precharge circuit.

12. The display device according to claim 1, wherein the operation control circuit controls setting of the display pixels in a selective state by the scan driver circuit when the capacity component is set in a predetermined charged state by the precharge circuit.

13. The display device according to claim 1, wherein the display device further comprises a reset circuit which discharges the electric charge stored at least in the display pixels and sets the display pixels in a reset state;

and

the operation control circuit controls setting of the display pixels in a selective state by the scan driver circuit when discharging the electric charge stored in the display pixels by the reset circuit.

14. The display device according to claim 13, wherein the reset circuit comprises a switching circuit which simultaneously applies a reset voltage to all the signal lines and discharges the electric charge stored in the storage capacitor.

15. The display device according to claim 13, wherein the scan driver circuit comprises:

a means which sequentially applies the scanning signal to each of the plurality of scanning lines and sequentially sets the display pixels for each arrayed row of the display panel in a selective state; and

a means which simultaneously applies the scanning signal to all the scanning lines and simultaneously sets all the display pixels arrayed in the display panel in a selective state.

16. The display device according to claim 13, wherein the scan driver comprises a means which generates and outputs a reset control signal for controlling the reset circuit operating state.

17. The display device according to claim 1, wherein the light emitting devices constitute organic electroluminescent devices.

18. A drive control method of a display device which displays image information based on display data,

the display device comprising a display panel which has a plurality of signal lines and a plurality of scanning lines situated in directions to mutually intersect and a plurality of display pixels containing current control type light emitting devices positioned near each intersecting point of those plurality of signal lines and plurality of scanning lines,

the drive control method comprises at least:

setting the light emitting devices in a non-light emitting state as precharge voltage which is applied to each of the plurality of signal lines and setting a capacity component attached to each of the signal lines as a predetermined charged state;

setting the display pixels in a selective state and setting the light emitting devices in a non-light emitting state;

supplying a gradation current to the display pixels via each of the plurality of signal lines based on the display data luminosity gradation component and storing an electric charge based on the gradation current in the display pixels; and

setting the display pixels in a non-selective state and setting the light emitting devices in a state which performs a light emitting operation based on the electric charge stored in the display pixels.

19. The drive control method of the display device according to claim 18, wherein the capacity component includes a capacitor formed within the wiring between the signal lines and the scanning lines.

20. The drive control method of the display device according to claim 19, wherein the capacity component further includes a storage capacitor formed in the display pixels which contribute to a light emitting operation of the light emitting devices.

21. The drive control method of the display device according to claim 20, wherein the precharge voltage sets the light emitting devices provided in the display pixels based on voltage charged in the storage capacitor for performing a light emitting operation at a specified luminosity gradation.

22. The drive control method of the display device according to claim 21, wherein the specified luminosity gradation constitutes the lowest gradation in a range of luminance gradations.

23. The drive control method of the display device according to claim 20, wherein the precharge voltage sets voltage charged in the storage capacitor so as to constitute voltage which does not cause an “

ON”

state in an active device for light emitting drive that contributes to a light emitting operation of the light emitting devices.

24. The drive control method of the display device according to claim 18, wherein operation of setting the capacity component in a predetermined charged state executes only once at timing before operation of supplying the gradation current to the display pixels corresponding to each of the scanning lines.

25. The drive control method of the display device according to claim 18, wherein operation of setting the capacity component in a predetermined charged state executes every cycle for each timing that supplies the gradation current to the display pixels corresponding to each of the scanning lines during operation of supplying the gradation current to the display pixels.

26. The drive control method of the display device according to claim 18, wherein operation of setting the capacity component in a predetermined charged state is executed in setting state of the display pixels in a non-selective state.

27. The drive control method of the display device according to claim 18, wherein operation of setting the capacity component in a predetermined charged state is executed in setting state of the display pixels in a selective state.

28. The drive control method of the display device according to claim 18, wherein the drive method further comprises:

setting the display pixels as a selective state;

applying reset voltage to the signal lines;

discharging an electric charge stored by the storage capacitor provided at least in the display pixels; and

setting the display pixels in a reset state.

29. The drive control method of the display device according to claim 28, wherein operation of setting the display pixels in a reset state executes only once at timing before operation of supplying the gradation current to the display pixels corresponding to each of the scanning lines.

30. The drive control method of the display device according to claim 28, wherein operation of setting the display pixels in a reset state executes every cycle for each timing that supplies the gradation current to the display pixels corresponding to each of the scanning lines during operation of supplying the gradation current to the display pixels.