Self-luminous display device and driving method of the same
A self-luminous display device includes: pixel circuits; and a drive signal generating circuit, wherein each of the pixel circuits includes a light-emitting diode, a drive transistor connected to a drive current path of the light-emitting diode, and a holding capacitor coupled to a control node of the drive transistor, and the drive signal generating circuit generates the drive signal containing a second level signal adapted to stop the light emission without reverse-biasing the light-emitting diode, a first level signal, lower than the second level signal, adapted to reverse-bias the light-emitting diode, and a third level signal, higher than the second level signal, adapted to enable the light-emitting diode to emit light, the drive signal generating circuit supplying the drive signal to the pixel circuits.
1. A self-luminous display device comprising:
pixel circuits and a drive circuit,
at least one of the pixel circuits including:
a light-emitting element having diode characteristics,
a drive element for controlling a driving current for the light-emitting element,
a capacitor element in electrical communication with a potential of a control node of the drive element,
a switching element for sampling a potential signal from a signal line to the capacitor element; and
the drive circuit being configured to:
execute a first process to set an anode electrode of the light-emitting element in an intermediate state, thereby discharging a charge via the anode electrode of the light-emitting element to a first potential line,
execute a second process to set the anode electrode of the light-emitting element to a low state, and apply a potential signal to the capacitor element via the switching element,
execute a third process to store a data voltage in the capacitor element, the data voltage depending on characteristic information of the drive element and image signal information, and
execute a fourth process to set the anode electrode of the light-emitting element to an active state, and supplying a driving current to the light-emitting element via the drive element, the drive element controlling the driving current according to the data voltage.
2. The self-luminous display device according to claim 1 ,
wherein a potential of the anode electrode of the light-emitting element in an active state is higher than a potential of the anode electrode of the light-emitting element in an intermediate state, and a potential of the anode electrode of the light-emitting element in an intermediate state is higher than a potential of the anode electrode of the light-emitting element in a low state.
3. The self-luminous display device according to claim 2 , wherein the driving circuit executes the first and the second process by setting the anode electrode of the light-emitting element to the corresponding state via the first potential line.
4. The self-luminous display device according to claim 1 further comprising a second potential line, wherein the drive transistor and the light emitting element are serially connected between the first potential line and the second potential line in each of the pixel circuits.
5. The self-luminous display device according to claim 3 further comprising a second potential line,
wherein the cathode electrode of the light emitting element is connected to the second potential line, and
the first potential line provides a potential not lower that the second potential line so as to set the anode electrode of the light-emitting element in an intermediate state in the first process.
6. The self-luminous display device according to claim 1 , wherein the drive circuit is configured to:
execute the first process so as to set the light-emitting element in an intermediate state between a reverse-biased and an emission state; and
execute the second process so as to set the light-emitting element in the reverse-biased state.
7. The self-luminous display device according to claim 1 wherein the duration from the beginning of the first process to the beginning of the second process in each of the pixel circuits is variable in accordance with a specific condition.
8. The self-luminous display device according to claim 1 ,
wherein said at least one of the pixel circuits further comprises a reset element for providing a reference potential to the capacitive element, and an emission control element disposed between the drive transistor and the light emitting element.
9. The self-luminous display device according to claim 1 , wherein the capacitive element comprises a holding capacitor electrically connected to the control node of the drive transistor.
10. The self-luminous display device according to claim 9 , wherein
the capacitive element further comprises an additional capacitance connected between the holding capacitor and a second potential line.
11. The self-luminous display device according to claim 10 , wherein the additional capacitive element is a capacitive component of the light emitting element.
12. The self-luminous display device according to claim 1 , wherein the drive element comprises a thin film transistor, and the characteristic information of the drive element includes a threshold voltage value of the thin film transistor.
13. The self-luminous display device according to claim 12 , wherein the characteristic information of the drive element further includes a mobility value of the thin film transistor.
14. The self-luminous display device according to claim 1 , wherein the drive circuit is configured to execute the third process by feeding back a current flow through the drive element to the capacitor element during an image signal potential is applied to a node of the capacitor element.
15. The self-luminous display device according to claim 9 , wherein the drive circuit is configured to execute the third process by feeding back a current flow through the drive element to a first node of the holding capacitor during an image signal potential is applied to a second node of the holding capacitor.
16. An electronic apparatus comprising a control unit, a drive circuit, and a display panel including a pixel circuits disposed in a matrix form,
at least one of the pixel circuits including:
a light-emitting element having a diode characteristics,
a drive element for controlling a driving current for the light-emitting element,
a capacitor element configured to set a potential of a control node of the drive element,
a switching element for sampling a potential signal to the capacitor element from a signal line; and
the drive circuit being configured to control said at least one pixel circuits in response to a process of the control unit, such that:
during a first process the anode electrode of the light-emitting element is set to an intermediate state, thereby discharging a charge via an anode electrode of the light-emitting element to a first potential line which is connected to a plurality of the pixel circuits,
and thereafter, the anode electrode of the light-emitting element is set to a low state, and applying a potential signal to the capacitor element via the switching element,
and storing data voltage information in the capacitor element, the data voltage depending on threshold voltage information of the drive element and image signal information, and
thereafter setting the anode electrode of the light-emitting element to an active state, and supplying a driving current to the light-emitting element via the drive element, the drive element controlling the driving current according to the data voltage information.
17. The electronic apparatus according to claim 16 , wherein the control unit adjusts brightness of an image displayed on the display panel in accordance with a surrounding brightness environment or a user preference.
18. The electronic apparatus according to claim 16 , wherein the duration from the beginning of the first process to the beginning of the second process in each of the pixel circuits is variable in accordance with a specific condition, and the specific condition being the surrounding brightness environment or the user preference.
19. The electronic apparatus according to claim 16 ,
wherein a potential of the anode electrode of the light-emitting element in an active state is higher than the anode electrode of the light-emitting element in an intermediate state, and a potential of the anode electrode of the light-emitting element in an intermediate state is higher than the anode electrode of the light-emitting element in a low state.
20. The electronic apparatus according to claim 16 , wherein the driving circuit executes the first and the second process by setting the anode electrode of the light-emitting element to the corresponding state via the first potential line.
21. The electronic apparatus according to claim 16 , wherein the driving circuit executes the first and the second process by setting the anode electrode of the light-emitting element to the corresponding state via the first potential line.
22. The electronic apparatus according to claim 16 further comprising a second potential line, wherein the drive transistor and the light emitting element are serially connected between the first potential line and the second potential line in each of the pixel circuits.
23. The self-luminous display device according to claim 16 further comprising a second potential line,
wherein the cathode electrode of the light emitting element is connected to the second potential line, and
the first potential line provides a potential not lower that the second potential line so as to set the anode electrode of the light-emitting element in an intermediate state in the first process.
24. The electronic apparatus according to claim 16 ,
wherein said at least one of the pixel circuits further including a reset element for providing a reference potential to the capacitive element, and a emission control element disposed between the drive transistor and the light emitting element.
25. The electronic apparatus according to claim 16 , wherein
the capacitive element comprises a holding capacitor directly connected to the control node of the drive transistor, and an additional capacitance connected to a second potential line.
26. The self-luminous display device according to claim 1 , wherein the drive circuit is configured to execute the third process by feeding back a current flow through the drive element to the capacitor element during an image signal potential is applied to a node of the capacitor element.
27. The self-luminous display device according to claim 25 , wherein the drive circuit is configured to execute the third process by feeding back a current flow through the drive element to a first node of the holding capacitor during an image signal potential is applied to a second node of the holding capacitor.
28. A method for driving a self-luminous display device comprising pixel circuits, at least one of the pixel circuits including a light-emitting element having diode characteristics, a drive element for controlling a driving current for the light-emitting element, and a capacitor element configured to set a potential of a control node of the drive element, the display device further comprising a switching element for sampling a potential signal from a signal line to the capacitor element, the driving method comprising:
a first process to set an anode electrode of the light-emitting element in an intermediate state, and to discharge a charge via the anode electrode of the light-emitting element to a first potential line,
a second process to set the anode electrode of the light-emitting element to a low state, and applying a potential signal to the capacitor element via the switching element,
a third process to store data voltage information in the capacitor element, the data voltage depending on characteristic information of the drive element and image signal information, and
a fourth process to set the anode electrode of the light-emitting element to an active state, and supplying a driving current to the light-emitting element via the drive element, the drive element controlling the driving current according to the data voltage information.