Method and system for driving an active matrix display circuit

• US 10,229,647 B2
• Filed: 09/19/2014
• Issued: 03/12/2019
• Est. Priority Date: 01/09/2006
• Status: Active Grant

• Current Assignee: IGNIS Innovation Incorporated
• Original Assignee: IGNIS Innovation Incorporated
• Inventors: Nathan, Arokia, Chaji, Gholamreza
• Primary Examiner(s): Boddie, William
• Assistant Examiner(s): Elnafia, Saifeldin E
• Application Number:
  US14/491,885
• Publication Number:
  US 20150009191A1
• Time in Patent Office: 1,635 Days
• CPC Class Codes: G09G 2300/0417 Special arrangements specific to the use of low carrier mobility technology
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2300/043 Compensation electrodes or other additional electrodes in matrix displays related to distortions or compensation signals, e.g. for modifying TFT threshold voltage in column driver
• CPC Class Codes: G09G 2300/0809 Several active elements per pixel in active matrix panels
• 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 2310/0243 Details of the generation of driving signals
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• 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 2310/0272 Details of drivers for data electrodes, the drivers communicating data to the pixels by means of a current
• 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 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3266 Details of drivers for scan electrodes
• CPC Class Codes: G09G 3/3685 Details of drivers for data electrodes
• CPC Class Codes: G09G 3/3696 Generation of voltages supplied to electrode drivers

Abstract

A method and system for driving an active matrix display is provided. The system includes a drive circuit for a pixel having a light emitting device. The drive circuit includes a drive transistor for driving the light emitting device. The system includes a mechanism for adjusting the gate voltage of the drive transistor.

Claims

1. A display comprising:

an array of pixel circuits arranged in rows and columns, each of the pixel circuits including;

a light emitting device for emitting light; and

a drive circuit for driving the light emitting device;

a temperature sensor associated with at least one pixel circuit and having a sensing terminal coupled to an internal node of a first pixel circuit of the at least one pixel circuit, the drive circuit of the first pixel circuit coupled directly to the internal node, a conductance of the temperature sensor depending upon the temperature of the first pixel circuit, a changing voltage of the internal node discharging through the temperature sensor based on the conductance of the temperature sensor constituting a time-varying sensor output of the temperature sensor,

a read-back circuit controllably coupled to said temperature sensor via said internal node and producing a time-varying output signal based on said time-varying sensor output when coupled to said temperature sensor, said internal node being interposed between said temperature sensor and said read-back circuit,

at least one controllable switch coupling said read-back circuit to said temperature sensor, and,

a data driver circuit coupled to said read-back circuit and to said pixels and providing programming signals to said pixels based in part on variations in said time-varying output signal from said read-back circuit.

2. The display of claim 1, wherein the temperature sensor is shared between two or more of the pixel circuits.

3. The display of claim 1, wherein the sensing terminal of the temperature sensor is controllably coupled to the internal node of the pixel circuit.

4. The display of claim 1, wherein the time-varying output signal of the read-back circuit is used to compensate for the change in the characteristics of the pixel circuit by calibrating a programming voltage stored in a storage capacitor of the pixel circuit.

5. The display of claim 4, which includes a data line controllably coupled to said storage capacitor via said internal node.

6. The display of claim 1, which includes multiple temperature sensors associated with different pixels or groups of pixels, and multiple read-back circuits, each of which is coupled to a different temperature sensor.

7. The display of claim 6, wherein the time-varying output signal of the read-back circuit is used to compensate for the change in the characteristics of the pixel circuit by calibrating a programming voltage stored in a storage capacitor of the pixel circuit.

8. The display of claim 1, in which the programming signals are calibrated based on the time-varying output signal of the read-back circuit.

9. The display of claim 1, in which the data driver circuit generates programming data, calibrates the programming data, and drives data lines to the pixels with the calibrated programming data.

10. The display of claim 1, wherein said programming signals compensate for the change in the temperature of the pixel circuit.