Electroluminescent display panel and method for operating the same

• US 20030197663A1
• Filed: 12/27/2002
• Published: 10/23/2003
• Est. Priority Date: 12/27/2001
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Park, Joon Kyu, Lee, Han Sang, Lee, Myung Ho
• Granted Patent: US 7,324,074 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 2300/0861 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 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• 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 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element

Abstract

Electroluminescent display panel and method for operating the same. The electroluminescent display panel having a plurality of unit pixels defined by a plurality of gatelines, and a plurality of sourcelines running perpendicular to each other, the unit pixel including a first switching device, a capacitor having a first terminal connected to an output terminal of the first switching device, and a second terminal connected to a power source voltage terminal, a second switching device connected to the power source voltage terminal, an electroluminescent part, and a light emission suppressing part connected to the one end of the capacitor for turning off the electroluminescent part for a preset period during a period before the present frame is operated, by receiving an enable signal that causes discharge of the capacitor and discharging a charge stored in the capacitor, thereby fabricating a high definition display.

Claims

1. An electroluminescent display panel having a plurality of unit pixels defined by a plurality of gatelines, and a plurality of sourcelines running perpendicular to each other, the unit pixel comprising:

a first switching device responsive to a signal applied to the gateline for switching a data signal;

a capacitor having a first terminal connected to an output terminal of the first switching device, and a second terminal connected to a power source voltage terminal, for having a data voltage provided thereto through the first switching device and charged thereto;

a second switching device connected to the power source voltage terminal for being switched by a voltage induced at the first terminal of the capacitor;

an electroluminescent part for emitting a light by the power source voltage provided through the second switching device; and

a light emission suppressing part connected to the one end of the capacitor for turning off the electroluminescent part for a preset period during a period before the present frame is operated, by receiving an enable signal that causes discharge of the capacitor and discharging a charge stored in the capacitor.

2. An electroluminescent display panel as claimed in claim 1, wherein the first switching device, the second switching device, and the light emission suppressing part includes a first type transistor.

3. An electroluminescent display panel as claimed in claim 2, wherein the first type transistor is a PMOS transistor.

4. An electroluminescent display panel as claimed in claim 1, wherein the light emission suppressing part is connected in parallel with the capacitor.

5. An electroluminescent display panel as claimed in claim 1, wherein the light emission suppressing part is connected between a first terminal and a second terminal of the capacitor.

6. An electroluminescent display panel as claimed in claim 1, wherein the light emission suppressing part is connected between an output terminal of the first switching device and an output terminal of the second switching device.

7. An electroluminescent display panel as claimed in claim 1, wherein the enable signal is provided from the light emission suppress drive part which provides a low level pulse to the plurality of gatelines before application of the enable signal.

8. An electroluminescent display panel as claimed in claim 1, wherein the enable signal is a signal enabled by a front end gateline of the plurality of gatelines.

9. An electroluminescent display panel as claimed in claim 1, further comprising a third switching device between the second switching device and the electroluminescent part operative in response to the enable signal.

10. An electroluminescent display panel as claimed in claim 9, wherein the third switching device includes a second type transistor.

11. An electroluminescent display panel as claimed in claim 10, wherein the second type transistor is an NMOS transistor.

12. A method as claimed in claim 11, wherein the first and second switching devices are PMOS transistors.

11-1. A method for operating an electroluminescent display panel having a plurality of unit pixels each defined by gatelines and sourcelines, both arranged to cross each other, first and second switching devices, a capacitor, an electroluminescent part, and a light emission suppressing part, the method comprising:

providing an erase signal to the light emission suppressing part for discharging a voltage charged in the capacitor of a prior frame before the present frame is operative; and

applying an enable signal to the gateline and applying a data voltage to the sourceline, for charging the data voltage to the capacitor through the first switching device, and turning on the second switching device to provide a power source voltage to the electroluminescent part to make the electroluminescent part to emit a light for a time period.

13. A method for operating an electroluminescent display panel having a plurality of unit pixels, gatelines and sourcelines, both arranged to cross each other, a first switching device for switching a data signal in response to a signal provided to the gateline, a capacitor for having a data voltage provided through the first switching device and charged thereto, a second switching device connected to a power source voltage terminal for being switched by a voltage induced at the capacitor, an electroluminescent part for emitting a light by a power source voltage provided through the second switching device, the method comprising:

applying a data voltage to the sourceline, dividing each frame into a normal period and a black period, and applying a real data in the normal period and applying a black data voltage in the black data period;

enabling gatelines of the plurality of unit pixels progressively in the normal period and the black data period; and

in the enabling of the gatelines, applying the black data voltage to the gatelines in the black data period, for displaying a picture while turning off the electroluminescent part repeatedly at fixed intervals.

14. A method as claimed in claim 13, wherein the gate signal is loaded on the gateline, with the gate signal divided into a first gate signal and a second gate signal.

15. as claimed in claim 13, wherein the first gate signal is applied to the normal period, and the second gate signal is applied to the black data period.

16. A method as claimed in claim 13, wherein the black data voltage is a voltage for turning off the second switching device.

17. A method as claimed in claim 16, wherein the black data voltage is a voltage ranging from one of the power source voltage, to a threshold voltage of the second switching device, and to the power source voltage.