Method and system for programming, calibrating and driving a light emitting device display

• US 9,970,964 B2
• Filed: 03/10/2015
• Issued: 05/15/2018
• Est. Priority Date: 12/15/2004
• Status: Active Grant

• Current Assignee: IGNIS Innovation Incorporated
• Original Assignee: IGNIS Innovation Incorporated
• Inventors: Nathan, Arokia, Chaji, Gholamreza, Servati, Peyman
• Primary Examiner(s): Abdulselam, Abbas I
• Application Number:
  US14/643,584
• Publication Number:
  US 20150192621A1
• Time in Patent Office: 1,162 Days
• CPC Class Codes: G01R 19/0092 measuring current only all subgroups of G01R19/00 take precedence
• 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 2310/0262 The addressing of the pixel, in a display other than an active matrix LCD, involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependent on signals of two data electrodes
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• 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 2320/0295 by monitoring each display pixel
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2320/045 Compensation of drifts in the characteristics of light emitting or modulating elements
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 3/006 Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays testing individual LED's G01R31/2635; testing lamps G01R31/44; testing of optical features of LCD displays G02F1/1309
• CPC Class Codes: G09G 3/3208 organic, e.g. using organic light-emitting diodes [OLED]
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3241 the current through the light-emitting element being set using a data current provided by the data driver, e.g. by using a two-transistor current mirror
• CPC Class Codes: G09G 3/3258 with pixel circuitry controlling the voltage across the light-emitting element
• CPC Class Codes: G09G 3/3283 in which the data driver supplies a variable data current for setting the current through, or the voltage across, the light-emitting elements
• 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 method and system for programming, calibrating and driving a light emitting device display is provided. The system may include extracting a time dependent parameter of a pixel for calibration.

Claims

1. A system for measuring a time-dependent parameter among multiple columns of pixel circuits in a display array, the system comprising:

a monitor line; and

an extraction block shared between at least two columns of pixel circuits in the display array through the monitor line, each of the pixel circuits including a light emitting device controlled by a driving transistor, the driving transistor being connectable to the monitor line via a switch transistor, the extraction block extracting at least a time-dependent parameter of each of the pixel circuits with use of electrical signals received from the pixel circuits over the monitor line.

2. The system of claim 1, wherein the extraction block includes a current sense amplifier or a current comparator.

3. The system of claim 1, wherein the current on the monitor line is compared against a reference current.

4. The system of claim 1, wherein the time-dependent parameter includes a threshold voltage of the driving transistor.

5. The system of claim 1, wherein the time-dependent parameter further includes a degradation of the light emitting device.

6. The system of claim 1, wherein the time-dependent parameter further includes a degradation of the light emitting device.

7. The system of claim 1, wherein the extraction block is shared among a few columns of pixel circuits in the display array.

8. The system of claim 1, wherein the extraction by the extraction block of at least the time-dependent parameter is merged with a programming cycle in which programming information is transferred to each of the pixel circuits.

9. The system of claim 1, further comprising a calibration scheduler and memory block configured to enable a normal operation mode or a calibration mode for a selected one of the at least two columns.

10. The system of claim 1, wherein during the calibration mode, the pixel circuits are calibrated based on at least one of their aging or their usage during the normal operation mode of the display array.

11. The system of claim 1, wherein the pixel circuits are calibrated in real time by the calibration scheduler and memory block.

12. The system of claim 1, wherein programming data associated with each of the pixel circuits is calibrated by the calibration scheduler and memory block with corresponding information extracted by the extraction block.

13. The system of claim 1 wherein the calibration scheduler and memory block is shared between the at least two columns, and each of the pixel circuits is calibrated one at a time.

14. The system of claim 1, wherein the calibration scheduler and memory block includes a calibration memory that stores at least the time-dependent parameter extracted by the extraction block for each of the pixel circuits.

15. The system of claim 1, wherein each of the pixel circuits is a current-mode pixel circuit.

16. The system of claim 1, wherein each of the pixel circuits is current-programmed.

17. The system of claim 1, wherein during the extraction of at least the time-dependent parameter, a first current or voltage is applied to the monitor line, and wherein during a programming cycle, a second current or voltage different from the first current or voltage is applied to the monitor line to transfer programming information related to the second current or voltage to each of the pixel circuits.