Display system with compensation techniques and/or shared level resources

• US 10,319,307 B2
• Filed: 04/23/2014
• Issued: 06/11/2019
• Est. Priority Date: 06/16/2009
• Status: Active Grant

• Current Assignee: IGNIS Innovation Incorporated
• Original Assignee: IGNIS Innovation Incorporated
• Inventors: Chaji, Gholamreza, Zahirovic, Nino
• Primary Examiner(s): Shankar, Vijay
• Application Number:
  US14/775,450
• Publication Number:
  US 20160027382A1
• Time in Patent Office: 1,875 Days
• Field of Search: 345 76- 83, 345204-215
• CPC Class Codes: G09G 2300/0452 Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• 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 2310/0291 Details of output amplifiers or buffers arranged for use in a driving circuit
• CPC Class Codes: G09G 2320/0223 Compensation for problems related to R-C delay and attenuation in electrodes of matrix panels, e.g. in gate electrodes or on-substrate video signal electrodes
• 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 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2320/0673 for control of gamma adjustment, e.g. selecting another gamma curve
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 2340/06 Colour space transformation
• 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 3/3233 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 voltage-programmed display system allows measurement of effects on pixels in a panel that includes both active pixels and reference pixels coupled to a supply line and a programming line. The reference pixels are controlled so that they are not subject to substantial changes due to aging and operating conditions over time. A readout circuit is coupled to the active pixels and the reference pixels for reading at least one of current, voltage or charge from the pixels when they are supplied with known input signals. The readout circuit is subject to changes due to aging and operating conditions over time, but the readout values from the reference pixels are used to adjust the readout values from the active pixels to compensate for the unwanted effects.

Claims

1. A method of using a compressed gamma in a video display having an array of pixel circuits, each of the pixel circuits including an organic light emitting device, the method comprising:

defining a subset of a dynamic gamma range bounded by an available voltage range of a source driver of each of the pixel circuits,

allocating a scale of bits to the defined subset to produce a compressed gamma range,

shifting the compressed gamma range up or down according to an aging of the pixel, and

applying the compressed gamma range to a video signal applied to the display.

2. The method of claim 1, further comprising:

applying a non-linear gamma to the video signal to increase resolution at low gray levels.

3. A display system including an array of pixels arranged on a panel, each of the pixels including an organic light emitting device, and a source driver for providing video data to the pixels, wherein a subset of a dynamic gamma range is bounded by an available voltage range of the source driver, a scale of bits is allocated to define the subset to produce a compressed a gamma range, where the compressed gamma range is shifted up or down based on an aging of the panel and applied to a video signal applied to the display system.

4. The display system of claim 3, where the gamma range is shifted up or down to obtain a desired black level and a peak brightness after display aging.