LIGHT-EMITTING COMPONENT DRIVING CIRCUIT AND RELATED PIXEL CIRCUIT AND APPLICATIONS

• US 20130069852A1
• Filed: 09/10/2012
• Published: 03/21/2013
• Est. Priority Date: 09/19/2011
• Status: Abandoned Application

• Current Assignee: Wintek Corporation
• Original Assignee: Wintek Corporation
• Inventors: Liao, Wen-Tui, Wang, Wen-Chun, Han, Hsi-Rong, Huang, Chih-Hung
• Application Number:
  US13/607,811
• Publication Number:
  US 20130069852A1
• Time in Patent Office: Days
• US Class Current: 345/77
• CPC Class Codes: G09G 2300/0814 used for selection purposes, e.g. logical AND for partial update
• CPC Class Codes: G09G 2300/0819 used for counteracting undesired variations, e.g. feedback or autozeroing
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element

Abstract

A pixel circuit related to an organic light-emitting diode (OLED) is provided. When signals having appropriate operation waveforms are supplied, the circuit configuration (7T1C or 5T1C) of the pixel circuit keeps the current flowing through an OLED unaffected by the impact of IR drop on a power supply voltage Vdd (or mitigates the impact of the power supply voltage Vdd on the current) and prevents the current flowing through the OLED from changing with the Vth shift of a TFT for driving the OLED. Thereby, the luminance uniformity of an OLED display adopting the pixel circuit is greatly improved.

Claims

1. A light-emitting component driving circuit, comprising:

a driving unit, coupled between a power supply voltage and a light-emitting component, comprising a driving transistor, and controlling a driving current flowing through the light-emitting component in a light enable phase;

a data storage unit, coupled to the driving unit, comprising a shift-compensation transistor and a storage capacitor coupled between the driving transistor and a reference potential, and storing a data voltage and a threshold voltage of the shift-compensation transistor through the storage capacitor in a data-writing phase; and

a light-emitting control unit, coupled between the driving unit and the light-emitting component, and conducting the driving current from the driving unit to the light-emitting component in the light enable phase,

wherein in the light enable phase, the driving unit generates the driving current flowing through the light-emitting component in response to a cross-voltage of the storage capacitor, and the driving current is unaffected by a threshold voltage of the driving transistor in response to the storage of the threshold voltage of the shift-compensation transistor.

2. The light-emitting component driving circuit according to claim 1, wherein the data storage unit further stores the power supply voltage through the storage capacitor in the data-writing phase,

wherein in the light enable phase, the driving current is further unaffected by the power supply voltage in response to the storage of the power supply voltage.

3. The light-emitting component driving circuit according to claim 2, wherein a gate of the driving transistor is coupled to a first end of the storage capacitor and a gate and a source of the shift-compensation transistor, and a source of the driving transistor is coupled to the power supply voltage,

wherein the data storage unit further comprises:

a writing transistor, having a gate for receiving a write scan signal, a source for receiving the data voltage, and a drain coupled to a second end of the storage capacitor;

a transmission transistor, having a gate for receiving the write scan signal, a source coupled to the power supply voltage, and a drain coupled to a drain of the shift-compensation transistor; and

a coupling transistor, having a gate for receiving a light enable signal, a source coupled to the second end of the storage capacitor, and a drain coupled to the reference potential,

wherein the data storage unit further initializes a voltage on the first end of the storage capacitor in response to a reset scan signal in a reset phase, and the data storage unit further comprises;

a reset transistor, having a gate and a source coupled with each other for receiving the reset scan signal and a drain coupled to the first end of the storage capacitor.

4. The light-emitting component driving circuit according to claim 3, wherein the light-emitting control unit comprises:

a light-emitting control transistor, having a gate for receiving the light enable signal and a source coupled to a drain of the driving transistor,

wherein a first terminal of the light-emitting component is coupled to a drain of the light-emitting control transistor, and a second terminal of the light-emitting component is coupled to the reference potential,

wherein the driving transistor, the shift-compensation transistor, the writing transistor, the reset transistor, the transmission transistor, the coupling transistor, and the light-emitting control transistor are all P-type transistors,

wherein the light-emitting component is an organic light-emitting diode (OLED), the first terminal of the light-emitting component is an anode of the OLED, and the second terminal of the light-emitting component is a cathode of the OLED.

5. The light-emitting component driving circuit according to claim 4, wherein the light-emitting component driving circuit is an OLED driving circuit, and the OLED driving circuit sequentially enters the reset phase, the data-writing phase, and the light enable phase,

wherein in the reset phase, the reset scan signal is enabled, and the write scan signal and the light enable signal are disabled,

wherein in the data-writing phase, the write scan signal is enabled, and the reset scan signal and the light enable signal are disabled,

wherein in the light enable phase, the light enable signal is enabled, and the reset scan signal and the write scan signal are disabled.

6. The light-emitting component driving circuit according to claim 1, wherein in the light enable phase, an impact of the power supply voltage on the driving current is mitigated in response to the data voltage related to the power supply voltage.

7. The light-emitting component driving circuit according to claim 6, wherein a gate of the driving transistor is coupled to a first end of the storage capacitor and a gate and a source of the shift-compensation transistor, a source of the driving transistor is coupled to the power supply voltage, and a second end of the storage capacitor is coupled to the reference potential,

wherein the data storage unit further comprises:

a writing transistor, having a gate for receiving a write scan signal, a source for receiving the data voltage, and a drain coupled to a drain of the shift-compensation transistor,

wherein the data storage unit further initializes a voltage on the first end of the storage capacitor in response to a reset scan signal in a reset phase, and the data storage unit further comprises;

a reset transistor, having a gate and a source coupled with each other for receiving the reset scan signal and a drain coupled to the first end of the storage capacitor.

8. The light-emitting component driving circuit according to claim 7, wherein the light-emitting control unit comprises:

a light-emitting control transistor, having a gate for receiving a light enable signal and a source coupled to a drain of the driving transistor,

wherein a first terminal of the light-emitting component is coupled to a drain of the light-emitting control transistor, and a second terminal of the light-emitting component is coupled to the reference potential,

wherein the driving transistor, the shift-compensation transistor, the writing transistor, the reset transistor, and the light-emitting control transistor are all P-type transistors,

wherein the light-emitting component is an OLED, the first terminal of the light-emitting component is an anode of the OLED, and the second terminal of the light-emitting component is a cathode of the OLED.

9. The light-emitting component driving circuit according to claim 8, wherein the light-emitting component driving circuit is an OLED driving circuit, and the OLED driving circuit sequentially enters the reset phase, the data-writing phase, and the light enable phase,

wherein in the reset phase, the reset scan signal is enabled, and the write scan signal and the light enable signal are disabled,

wherein in the data-writing phase, the write scan signal is enabled, and the reset scan signal and the light enable signal are disabled,

wherein in the light enable phase, the light enable signal is enabled, and the reset scan signal and the write scan signal are disabled.

10. A pixel circuit, comprising:

a light-emitting component, emitting light in response to a driving current in a light enable phase;

a driving unit, coupled between a power supply voltage and the light-emitting component, comprising a driving transistor, and controlling the driving current flowing through the light-emitting component in the light enable phase;

a data storage unit, coupled to the driving unit, comprising a shift-compensation transistor and a storage capacitor coupled between the driving transistor and a reference potential, and storing a data voltage and a threshold voltage of the shift-compensation transistor through the storage capacitor in a data-writing phase; and

a light-emitting control unit, coupled between the driving unit and the light-emitting component, and conducting the driving current from the driving unit to the light-emitting component in the light enable phase,

wherein in the light enable phase, the driving unit generates the driving current flowing through the light-emitting component in response to a cross-voltage of the storage capacitor, and the driving current is unaffected by a threshold voltage of the driving transistor in response to the storage of the threshold voltage of the shift-compensation transistor.

11. The pixel circuit according to claim 10, wherein the data storage unit further stores the power supply voltage through the storage capacitor in the data-writing phase,

wherein in the light enable phase, the driving current is further unaffected by the power supply voltage in response to the storage of the power supply voltage.

12. The pixel circuit according to claim 11, wherein a gate of the driving transistor is coupled to a first end of the storage capacitor and a gate and a source of the shift-compensation transistor, and a source of the driving transistor is coupled to the power supply voltage,

wherein the data storage unit further comprises:

a writing transistor, having a gate for receiving a write scan signal, a source for receiving the data voltage, and a drain coupled to a second end of the storage capacitor;

a transmission transistor, having a gate for receiving the write scan signal, a source coupled to the power supply voltage, and a drain coupled to a drain of the shift-compensation transistor; and

a coupling transistor, having a gate for receiving a light enable signal, a source coupled to the second end of the storage capacitor, and a drain coupled to the reference potential,

wherein the data storage unit further initializes a voltage on the first end of the storage capacitor in response to a reset scan signal in a reset phase, and the data storage unit further comprises;

a reset transistor, having a gate and a source coupled with each other for receiving the reset scan signal and a drain coupled to the first end of the storage capacitor.

13. The pixel circuit according to claim 12, wherein the light-emitting control unit comprises:

a light-emitting control transistor, having a gate for receiving the light enable signal and a source coupled to a drain of the driving transistor,

wherein a first terminal of the light-emitting component is coupled to a drain of the light-emitting control transistor, and a second terminal of the light-emitting component is coupled to the reference potential,

wherein the driving transistor, the shift-compensation transistor, the writing transistor, the reset transistor, the transmission transistor, the coupling transistor, and the light-emitting control transistor are all P-type transistors,

wherein the light-emitting component is an OLED, the first terminal of the light-emitting component is an anode of the OLED, and the second terminal of the light-emitting component is a cathode of the OLED,

wherein the pixel circuit is an OLED pixel circuit,

wherein the driving unit, the data storage unit, and the light-emitting control unit form an OLED driving circuit, and the OLED driving circuit sequentially enters the reset phase, the data-writing phase, and the light enable phase,

wherein in the reset phase, the reset scan signal is enabled, and the write scan signal and the light enable signal are disabled,

wherein in the data-writing phase, the write scan signal is enabled, and the reset scan signal and the light enable signal are disabled,

wherein in the light enable phase, the light enable signal is enabled, and the reset scan signal and the write scan signal are disabled.

14. The pixel circuit according to claim 10, wherein in the light enable phase, an impact of the power supply voltage on the driving current is mitigated in response to the data voltage related to the power supply voltage.

15. The pixel circuit according to claim 14, wherein a gate of the driving transistor is coupled to a first end of the storage capacitor and a gate and a source of the shift-compensation transistor, a source of the driving transistor is coupled to the power supply voltage, and a second end of the storage capacitor is coupled to the reference potential,

wherein the data storage unit further comprises:

a writing transistor, having a gate for receiving a write scan signal, a source for receiving the data voltage, and a drain coupled to a drain of the shift-compensation transistor,

wherein the data storage unit further initializes a voltage on the first end of the storage capacitor in response to a reset scan signal in a reset phase, and the data storage unit further comprises;

a reset transistor, having a gate and a source coupled with each other for receiving the reset scan signal and a drain coupled to the first end of the storage capacitor.

16. The pixel circuit according to claim 15, wherein the light-emitting control unit comprises:

a light-emitting control transistor, having a gate for receiving a light enable signal and a source coupled to a drain of the driving transistor,

wherein a first terminal of the light-emitting component is coupled to a drain of the light-emitting control transistor, and a second terminal of the light-emitting component is coupled to the reference potential,

wherein the driving transistor, the shift-compensation transistor, the writing transistor, the reset transistor, and the light-emitting control transistor are all P-type transistors,

wherein the light-emitting component is an OLED, the first terminal of the light-emitting component is an anode of the OLED, and the second terminal of the light-emitting component is a cathode of the OLED,

wherein the pixel circuit is an OLED pixel circuit,

wherein the driving unit, the data storage unit, and the light-emitting control unit form an OLED driving circuit, and the OLED driving circuit sequentially enters the reset phase, the data-writing phase, and the light enable phase,

wherein in the reset phase, the reset scan signal is enabled, and the write scan signal and the light enable signal are disabled,

wherein in the data-writing phase, the write scan signal is enabled, and the reset scan signal and the light enable signal are disabled,

wherein in the light enable phase, the light enable signal is enabled, and the reset scan signal and the write scan signal are disabled.

17. An OLED display panel comprising the pixel circuit as claimed in claim 13.

18. An OLED display comprising the OLED display panel as claimed in claim 17.

19. An OLED display panel comprising the pixel circuit as claimed in claim 16.

20. An OLED display comprising the OLED display panel as claimed in claim 19.