OLED Display Aging Compensation via Calibration Current Measurement
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Solution Overview
Problem
OLED displays face issues with voltage threshold shifts and organic material degradation due to manufacturing variabilities and prolonged use, leading to decreased dynamic range and image artifacts, which existing compensation methods often address inadequately by requiring complex circuitry or reducing display lifetime.
Innovation Solution
A method involving the sequential display of calibration images with varying luminance values to measure and record current usage, calculate compensation parameters, and adjust input images accordingly, thereby compensating for performance changes in OLED displays without causing perceived luminance discontinuities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex compensation circuits are employed to address voltage threshold shifts and organic material degradation, then display uniformity and performance stability are improved, but device complexity increases and manufacturing cost increases
Solution Approach 1:
The patent extracts the compensation function from complex circuitry and implements it through a simplified measurement and lookup table approach. Instead of using complex feedback circuits to continuously compensate for threshold voltage shifts and organic material degradation, the system measures initial display characteristics, stores them in lookup tables, and applies pre-calculated compensation values, thereby achieving display uniformity without complex circuits
Solution Approach 2:
The patent creates a copy of the display's initial characteristics through measurement and stores them in lookup tables. This copied information is then used to generate compensation values that correct for aging effects, replacing the need for complex real-time compensation circuits with a simpler table-lookup-based system
2Reliability
If existing compensation methods are used to address threshold voltage shifts, then display performance is improved, but display lifetime is reduced
Solution Approach 1:
The patent performs preliminary measurement of the display's initial characteristics and creates lookup tables with compensation values before the display undergoes significant aging. This preliminary action allows the system to compensate for future aging effects without requiring continuous complex circuit operation that would reduce display lifetime
Solution Approach 2:
The display system uses its own measured initial characteristics to generate self-compensation values through lookup tables. This self-service approach eliminates the need for external complex compensation circuits that would consume additional power and reduce display lifetime, while still maintaining display performance through accurate self-correction of aging effects
Data Source
AI summary
A method of compensating an OLED display device having light-emitting elements that change with use, comprising the steps of: a) using the device to display images; b) sequentially displaying an ordered series of calibration images, wherein each of the calibration images have one or more corresponding flat fields, at least one of the corresponding flat fields of each calibration image of the ordered series has a different luminance value, and the calibration images are arranged in the ordered series so as to reduce perceived luminance discontinuities; c) measuring and recording current used by the display for each sequentially displayed calibration image; d) calculating compensation parameters based on the measured currents; e) compensating an input image using the compensation parameters; and f) displaying the compensated input image.