Self-luminous display device and driving method of the same

• US 20090153448A1
• Filed: 12/03/2008
• Published: 06/18/2009
• Est. Priority Date: 12/13/2007
• Status: Active Grant

• Current Assignee: JDI Design and Development GK
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Tomida, Masatsugu, Asano, Mitsuru
• Granted Patent: US 8,310,418 B2
• Time in Patent Office: Days
• US Class Current: 345/82
• CPC Class Codes: G09G 2300/0819 used for counteracting undesired variations, e.g. feedback or autozeroing
• CPC Class Codes: G09G 2300/0866 by means of changes in the pixel supply voltage
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0238 Improving the black level
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3266 Details of drivers for scan electrodes

Abstract

A self-luminous display device includes: pixel circuits; and a drive circuit, wherein each of the pixel circuits includes a light-emitting diode, a drive transistor connected to a drive current channel of the light-emitting diode, and a holding capacitor coupled to a control node of the drive transistor, the drive circuit applies a light emission enabling bias to the light-emitting diode after correcting the drive transistor and writing a data voltage to the control node, provides, during a light emission enabled period in which the light emission enabling bias is applied, a light emission interruption period adapted to change the light emission enabling bias to a non-light emission bias with the data voltage held by the holding capacitor, and performs a light emission disabling process, adapted to reverse-bias the light-emitting diode to stop the light emission, for a constant period after the light emission enabled period.

Claims

1. A self-luminous display device comprising:

pixel circuits; and

a drive circuit, wherein

each of the pixel circuits includes

a light-emitting diode,

a drive transistor connected to a drive current channel of the light-emitting diode, and

a holding capacitor coupled to a control node of the drive transistor,

the drive circuit applies a light emission enabling bias to the light-emitting diode after correcting the drive transistor and writing a data voltage to the control node,

the drive circuit provides, during a light emission enabled period in which the light emission enabling bias is applied, a light emission interruption period adapted to change the light emission enabling bias to a non-light emission bias with the data voltage held by the holding capacitor, and

the drive circuit performs a light emission disabling process, adapted to reverse-bias the light-emitting diode to stop the light emission, for a constant period after the light emission enabled period.

2. The self-luminous display device of claim 1, wherein

the voltage held by the holding capacitor is initialized during a light emission disabled period in which the light emission disabling process is performed.

3. The self-luminous display device of claim 1, wherein

the correction of the drive transistor is a mobility correction performed together with the writing of the data voltage to the control node.

4. The self-luminous display device of claim 1, wherein

the period of time from the beginning of the correction to the end of the light emission disabled period in which the light emission disabling process is performed is determined as a constant screen display period, and

the drive circuit controls the length of the light emission enabled period during which the light-emitting diode actually emits light by changing the length of the light emission interruption period.

5. The self-luminous display device of claim 1, wherein

the drive circuit stops the light emission of the light-emitting diode by reverse-biasing the same diode during the light emission interruption period and light emission disabled period in which the light emission disabling process is performed.

6. The self-luminous display device of claim 1, wherein

the drive circuit performs a false light emission, in which light cannot substantially be emitted although the light emission enabling bias is applied to the light-emitting diode, for a predetermined period at the beginning of the light emission enabled period, and

the drive circuit changes the light emission enabling bias to the non-light emission bias when the light emission interruption period begins after the false light emission and changes the non-light emission bias back to the light emission enabling bias after elapse of a predetermined period.

7. The self-luminous display device of claim 1, wherein

the drive circuit performs a false light emission, in which light cannot substantially be emitted although the light emission enabling bias is applied to the light-emitting diode, for a predetermined period at the end of the light emission enabled period, and

the drive circuit changes the light emission enabling bias to the non-light emission bias and initializes the held voltage when the light emission disabling process begins after the false light emission.

8. The self-luminous display device of claim 1, wherein

the drive circuit repeats a light emission enabled period, long enough for the light-emitting diode to be able to actually emit light, and the light emission interruption period a predetermined number of times during the light emission enabled period.

9. A driving method of a self-luminous display device, the self-luminous display device including

pixel circuits, each of the pixel circuits including

a light-emitting diode,

a drive transistor connected to a drive current channel of the light-emitting diode, and

a holding capacitor coupled to a control node of the drive transistor, the driving method comprising the steps of:

stopping the light emission by reverse-biasing the light-emitting diode for a constant period;

correcting the driving transistor and writing a data voltage to the control node;

applying a light emission enabling bias to the light-emitting diode according to the written data voltage; and

temporarily changing the light emission enabling bias to a non-light emission bias with the data voltage held by the holding capacitor halfway through the application of the light emission enabling bias.

10. The driving method of a self-luminous display device of claim 9, wherein

the light emission disabling process step stops the light emission of the light-emitting diode by reverse-biasing the same diode and initializes the voltage held by the holding capacitor.

11. The driving method of a self-luminous display device of claim 9, wherein

the correction and writing step, light emission enabling bias application step, light emission interruption step, recovery of the light emission enabling bias and light emission disabling process step in this order are determined as a constant screen display period, and

the length of the light emission enabled period during which the light-emitting diode actually emits light is controlled by changing the length of the light emission interruption period in the light emission enabling bias application step, light emission interruption step and recovery of the light emission enabling bias.