EL DISPLAY DEVICE AND DRIVING METHOD OF SAME

• US 20070222718A1
• Filed: 02/20/2007
• Published: 09/27/2007
• Est. Priority Date: 02/20/2006
• Status: Abandoned Application

• Current Assignee: Toshiba Matsushita Display Technology (Japan Display Incorporated)
• Original Assignee: Toshiba Matsushita Display Technology (Japan Display Incorporated)
• Inventors: Takahara, Hiroshi
• Application Number:
  US11/676,822
• Publication Number:
  US 20070222718A1
• 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 2300/0852 being a dynamic memory with more than one capacitor
• CPC Class Codes: G09G 2300/0861 with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes
• CPC Class Codes: G09G 2310/0218 with collection of electrodes in groups for n-dimensional addressing
• 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 2310/04 Partial updating of the display screen
• CPC Class Codes: G09G 2310/061 for resetting or blanking
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• CPC Class Codes: G09G 2320/0271 Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2340/0435 Change or adaptation of the frame rate of the video stream
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/2011 by amplitude modulation
• CPC Class Codes: G09G 3/2081 with combination of amplitude modulation and time modulation space and time error diffusion G09G3/2066
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3241 the current through the light-emitting element being set using a data current provided by the data driver, e.g. by using a two-transistor current mirror
• 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
• CPC Class Codes: G09G 3/3291 : in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements

Abstract

A driving method of an electroluminescent (EL) display device for driving the EL display device having EL elements placed in a matrix state thereon, has when a pixel line selected to write a video signal matches with a pixel line selected to supply a current to the EL elements, deselecting at least one of the pixel line selected to write the video signal and the pixel line selected to supply a current to the EL elements.

Claims

1. A driving method of an electroluminescent (EL) display device for driving the EL display device having EL elements placed in a matrix state thereon, comprising:

when a pixel line selected to write a video signal matches with a pixel line selected to supply a current to said EL elements,

deselecting at least one of the pixel line selected to write said video signal and the pixel line selected to supply a current to said EL elements.

4. The driving method of an EL display device according to claim 1, wherein:

controlling a writing of said video signal in a first gate driver circuit;

controlling a supplying of a current to said EL elements is exerted in a second gate driver circuit; and

operating said first gate driver circuit at a first operation frame rate faster than a second operation frame rate of said second gate driver circuit.

2. A driving method of an electroluminescent (EL) display device for driving the EL display device having EL elements placed in a matrix state thereon, comprising:

stopping a supply of a current to the EL elements of a pixel line selected to write a video signal in a matching period when said pixel line selected to write a video signal matches with a pixel line selected to supply a current to the EL elements; and

correcting luminance reduced by said stopping the supply of current by applying correction data to EL elements of a pixel line in a frame in which said stopping occurs or a frame before said frame in which said stopping occurs or a frame after said frame in which said stopping occurs.

5. The driving method of an EL display device according to claim 2, wherein:

controlling a writing of said video signal in a first gate driver circuit; and

controlling a supplying of a current to said EL elements in a second gate driver circuit, wherein

operating said first gate driver circuit at a first operation frame rate faster than a second operation frame rate of said second gate driver circuit.

3. A driving method of an electroluminescent (EL) display device for driving the EL display device having EL elements placed in a matrix state thereon, comprising:

executing a first operation frame rate for selecting a pixel line for writing a video signal;

executing a second operation frame rate for selecting a pixel line for supplying a current to said EL elements, wherein

said first operation frame rate is different from said second operation frame rate.

6. The driving method of an EL display device according to claim 3, wherein:

controlling a writing of said video signal in a first gate driver circuit;

controlling a supplying of a current to said EL elements is exerted in a second gate driver circuit;

operating said first gate driver circuit at a first operation frame rate faster than a second operation frame rate of said second gate driver circuit.

7. An electroluminescent (EL) display device having EL elements placed in a matrix, comprising:

a first selection portion configured to select a pixel line for writing a video signal;

a second selection portion configured to select a pixel line for lighting EL elements; and

a selection control portion configured to render the pixel line selected by at least one of said first selection portion and said second selection portion deselected when the pixel line selected by said first selection portion matches with the pixel line selected by said second selection portion.

11. The EL display device according to claim 7,

said second selection portion or said second gate driver circuit having an operation frame rate faster than an operation frame rate of said first selection portion or said first gate driver circuit.

15. The EL display device according to claim 7, wherein a duty ratio of a number of selected pixel lines to a total number of pixel lines of a display area is variable corresponding to a lighting rate.

8. An electroluminescent (EL) display device having EL elements placed in a matrix state thereon, comprising:

a first gate driver circuit configured to select a pixel line for writing a video signal;

a second gate driver circuit configured to select a pixel line for lighting EL elements; and

a selection control circuit having inputs including a first gate signal line connected to said first gate driver circuits and a second gate signal line connected to said second gate driver circuit.

9. The EL display device according to claim 8, wherein:

said first gate driver circuit having an operation frame rate different from an operation frame rate of said second gate driver circuit; and

said selection control circuit is configured to render the pixel line selected by at least one of said first gate driver circuit and said second gate driver circuit deselected when the pixel line selected by said first gate driver circuit matches with the pixel line selected by said second gate driver circuit.

12. The EL display device according to claim 8,

said second selection portion or said second gate driver circuit having an operation frame rate faster than an operation frame rate of said first selection portion or said first gate driver circuit.

13. The EL display device according to claim 9,

said second selection portion or said second gate driver circuit having an operation frame rate faster than an operation frame rate of said first selection portion or said first gate driver circuit.

16. The EL display device according to claim 8, wherein a duty ratio of a number of selected pixel lines to a total number of pixel lines of a display area is variable corresponding to a lighting rate.

17. The EL display device according to claim 9, wherein a duty ratio of a number of selected pixel lines to a total number of pixel lines of a display area is variable corresponding to a lighting rate.

19. The EL display device according to claim 9, wherein, of multiple input terminals of said selection control circuit, comprising:

multiple input terminals one of said multiple input terminals configured to be a gate signal line electrically connected to the first gate driver circuit or the second gate driver circuit.

10. An electroluminescent (EL) display device having EL elements placed in a matrix state thereon, comprising:

a first gate driver circuit configured to select a pixel line for writing a video signal; and

a second gate driver circuit configured to select a pixel line for lighting EL elements,

said first gate driver circuit having an operation frame rate different from an operation frame rate of said second gate driver circuit.

14. The EL display device according to claim 10,

said second selection portion or said second gate driver circuit having an operation frame rate faster than an operation frame rate of said first selection portion or said first gate driver circuit.

18. The EL display device according to claim 10, wherein a duty ratio of a number of selected pixel lines to a total number of pixel lines of a display area is variable corresponding to a lighting rate.

20. An electroluminescent (EL) display device having EL elements placed in a matrix state thereon, comprising:

a first selection circuit configured to select a pixel line for writing a video signal; and

a second selection circuit configured to selected a pixel line for lighting EL elements.