Cathode potential controller, self light emission display device, electronic apparatus, and cathode potential controlling method

• US 20080297055A1
• Filed: 05/21/2008
• Published: 12/04/2008
• Est. Priority Date: 05/30/2007
• Status: Active Grant

• Current Assignee: JDI Design and Development GK
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Ozawa, Atsushi, Handa, Tomoaki, Miyake, Hidekazu, Tada, Mitsuru
• Granted Patent: US 7,864,172 B2
• Time in Patent Office: Days
• US Class Current: 315/169.2
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0866 by means of changes in the pixel supply voltage
• CPC Class Codes: G09G 2320/029 by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2330/028 Generation of voltages supplied to electrode drivers in a matrix display other than LCD
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• 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 cathode potential controller for controlling a common cathode potential applied to a self light emission type display panel in which an emission state of each of pixels is driven and controlled in accordance with an active matrix drive system, the cathode potential controller including: a self light emitting element; a constant current source; an electrode-to-electrode voltage measuring portion; a cathode potential determining portion; and a cathode potential applying portion.

Claims

1. A cathode potential controller for controlling a common cathode potential applied to a self light emission type display panel in which an emission state of each of pixels is driven and controlled in accordance with an active matrix drive system, said cathode potential controller comprising:

a self light emitting element for voltage measurement disposed outside an effective display region;

a constant current source for supplying a constant current to said self light emitting element for voltage measurement;

an electrode-to-electrode voltage measuring portion measuring a potential developed at an anode electrode of said self light emitting element for voltage measurement, and measuring an electrode to electrode voltage of said self light emitting element for voltage measurement;

a cathode potential determining portion determining a cathode potential value by using a difference value between a measured value of the electrode to electrode voltage of said self light emitting element for voltage measurement, and a reference voltage value as a correction value; and

a cathode potential applying portion applying a cathode potential corresponding to the determined cathode potential value to a common cathode electrode of said self light emission type display panel.

2. The cathode potential controller according to claim 1, wherein the reference voltage value is the electrode to electrode voltage of said self light emitting element for voltage measurement at a room temperature.

3. The cathode potential controller according to claim 1, wherein when a power source voltage on a cathode electrode side is given in a form of a grounding potential, said cathode potential determining portion determines a value which is obtained by correcting an offset potential value with the difference value as the cathode potential value.

4. The cathode potential controller according to claim 1, wherein when a power source voltage on a cathode electrode side is supplied from a negative power source, said cathode potential determining portion determines the difference value as the cathode potential value.

5. A cathode potential controller for controlling a common cathode potential applied to a self light emission type display panel in which an emission state of each of pixels is driven and controlled in accordance with an active matrix drive system, said cathode potential controller comprising:

a constant current source for voltage measurement disposed outside an effective display region for supplying a constant current to a self light emitting element for display and measurement constituting a specific pixel, said self light emitting element for display and measurement being disposed inside said effective display region;

an electrode-to-electrode voltage measuring portion measuring a potential developed at an anode electrode of said self light emitting element for display and measurement constituting said specific pixel in a phase of measuring an electrode to electrode voltage of said self light emitting element for display and measurement, and measuring the electrode to electrode voltage of said self light emitting element for display and measurement;

a cathode potential determining portion determining a cathode potential value by using a difference value between a measured value of the electrode to electrode voltage of said self light emitting element for display and measurement, and a reference voltage value as a correction value; and

a cathode potential applying portion applying a cathode potential corresponding to the determined cathode potential value to a common cathode electrode of said self light emission type display panel.

6. The cathode potential controller according to claim 5, wherein the reference voltage value is the electrode to electrode voltage of said self light emitting element for display and measurement at a room temperature.

7. The cathode potential controller according to claim 5, wherein when a power source voltage on a cathode electrode side is given in a form of a grounding potential, said cathode potential determining portion determines a value which is obtained by correcting an offset potential value with the difference value as the cathode potential value.

8. The cathode potential controller according to claim 5, wherein when a power source voltage on a cathode electrode side is given from a negative power source, said cathode potential determining portion determines the difference value as the cathode potential value.

9. The cathode potential controller according to claim 5, further comprising a switching element disposed an a wiring path between said constant current source for voltage measurement and said specific pixel for switching-controlling supply of a constant current to said self light emitting element for voltage measurement constituting said specific pixel, said switching element being controlled so as to be closed in a phase of measuring the electrode to electrode voltage of said self light emitting element for voltage measurement, and being controlled so as to be opened in a phase of displaying an input image.

10. A self light emission display device comprising:

a self light emission type display panel for driving and controlling an emission state of each of pixels in accordance with an active matrix drive system;

a self light emitting element for voltage measurement disposed outside an effective display region;

a constant current source for supplying a constant current to said self light emitting element for voltage measurement;

an electrode-to-electrode voltage measuring portion measuring a potential developed at an anode electrode of said self light emitting element for voltage measurement, and measuring an electrode to electrode voltage of said self light emitting element for voltage measurement;

a cathode potential determining portion determining a cathode potential value by using a difference value between a measured value of the electrode to electrode voltage of said self light emitting element for voltage measurement, and a reference voltage value as a correction value; and

a cathode potential applying portion applying a cathode potential corresponding to the determined cathode potential value to a common cathode electrode of said self light emission type display panel.

11. A self light emission display device comprising:

a self light emission type display panel for driving and controlling an emission state of each of pixels in accordance with an active matrix drive system;

a constant current source for voltage measurement disposed outside an effective display region for supplying a constant current to a self light emitting element for display and measurement constituting a specific pixel, said self light emitting element for display and measurement being disposed inside said effective display region;

an electrode-to-electrode voltage measuring portion measuring a potential developed at an anode electrode of said self light emitting element for display and measurement constituting said specific pixel in a phase of measuring an electrode to electrode voltage of said self light emitting element for display and measurement, and measuring the electrode to electrode voltage of said self light emitting element for display and measurement;

a cathode potential determining portion determining a cathode potential value by using a difference value between a measured value of the electrode to electrode voltage of said self light emitting element for display and measurement, and a reference voltage value as a correction value; and

a cathode potential applying portion applying a cathode potential corresponding to the determined cathode potential value to a common cathode electrode of said self light emission type display panel.

12. An electronic apparatus comprising:

a self light emission type display panel for driving and controlling an emission state of each of pixels in accordance with an active matrix drive system;

a self light emitting element for voltage measurement disposed outside an effective display region;

a constant current source for supplying a constant current to said self light emitting element for voltage measurement;

an electrode-to-electrode voltage measuring portion measuring a potential developed at an anode electrode of said self light emitting element for voltage measurement, and measuring an electrode to electrode voltage of said self light emitting element for voltage measurement;

a cathode potential determining portion determining a cathode potential value by using a difference value between a measured value of the electrode to electrode voltage of said self light emitting element for voltage measurement, and a reference voltage value as a correction value;

a cathode potential applying portion applying a cathode potential corresponding to the determined cathode potential value to a common cathode electrode of said self light emission type display panel;

a system controlling portion; and

a manipulation inputting portion for said system controlling portion.

13. An electronic apparatus comprising:

a self light emission type display panel for driving and controlling an emission state of each of pixels in accordance with an active matrix drive system;

a constant current source for voltage measurement disposed outside an effective display region for supplying a constant current to a self light emitting element for display and measurement constituting a specific pixel, said self light emitting element for display and measurement being disposed inside said effective display region;

an electrode-to-electrode voltage measuring portion measuring a potential developed at an anode electrode of said self light emitting element for display and measurement constituting said specific pixel in a phase of measuring an electrode to electrode voltage of said self light emitting element for display and measurement, and measuring the electrode to electrode voltage of said self light emitting element for display and measurement;

a cathode potential determining portion determining a cathode potential value by using a difference value between a measured value of the electrode to electrode voltage of said self light emitting element for display and measurement, and a reference voltage value as a correction value;

a cathode potential applying portion applying a cathode potential corresponding to the determined cathode potential value to a common cathode electrode of said self light emission type display panel;

a system controlling portion; and

a manipulation inputting portion for said system controlling portion.

14. A cathode potential controlling method of controlling a common cathode potential applied to a self light emission type display panel in which an emission state of each of pixels is driven and controlled in accordance with an active matrix drive system, said self light emission type display panel having a self light emitting element for voltage measurement disposed outside an effective display region, and a constant current source for supplying a constant current to said self light emitting element for voltage measurement, said cathode potential controlling method comprising the steps of:

measuring a potential developed at an anode electrode of said self light emitting element for voltage measurement, and measuring an electrode to electrode voltage of said self light emitting element for voltage measurement;

determining a cathode potential value by using a difference value between a measured value of the electrode to electrode voltage of said self light emitting element for voltage measurement, and a reference voltage value as a correction value; and

applying a cathode potential corresponding to the determined cathode potential value to a common cathode electrode of said self light emission type display panel.

15. A cathode potential controlling method of controlling a common cathode potential applied to a self light emission type display panel in which an emission state of each of pixels is driven and controlled in accordance with an active matrix drive system, said self light emission type display panel being a constant current source for voltage measurement disposed outside an effective display region for supplying a constant current to a self light emitting element for display and measurement constituting a specific pixel, said self light emitting element for display and measurement being disposed inside said effective display region, said cathode potential controlling method comprising the steps of:

measuring a potential developed at an anode electrode of said self light emitting element for display and measurement constituting said specific pixel in a phase of measuring an electrode to electrode voltage of said self light emitting element for display and measurement, and measuring the electrode to electrode voltage of said self light emitting element for display and measurement;

determining a cathode potential value by using a difference value between a measured value of the electrode to electrode voltage of said self light emitting element for display and measurement, and a reference voltage value as a correction value; and

applying a cathode potential corresponding to the determined cathode potential value to a common cathode electrode of said self light emission type display panel.