OLED Display Compensator for Luminance Uniformity
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Solution Overview
Problem
Organic light emitting diode (OLED) displays face issues with luminance deterioration and non-uniformity due to transistor threshold voltage and electron mobility deviations, leading to image sticking and mura (unevenness), which existing compensation methods fail to accurately address.
Innovation Solution
An OLED display system that includes a compensator to detect and correct for threshold voltage and mobility deviations by sinking predetermined currents through driving transistors, determining compensation amounts, and generating corrected image data signals to ensure uniform luminance, using a combination of current sinkers, controllers, and memory to store and apply these corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional compensation methods are used to address transistor threshold voltage and mobility deviations, then some luminance uniformity can be achieved, but compensation accuracy is insufficient and image sticking remains
Solution Approach 1:
The patent applies preliminary action by measuring and storing transistor characteristics (threshold voltage, mobility) during the manufacturing process, then using this pre-acquired data to calculate compensation values before the display operates. This allows the system to compensate for deviations accurately from the start, preventing image sticking rather than correcting it after occurrence.
Solution Approach 2:
The patent implements feedback by continuously monitoring OLED luminance output and comparing it against expected values, then using this feedback to adjust compensation parameters. The system measures actual luminance, calculates deviation from target, and modifies compensation values accordingly to achieve uniform luminance across all pixels.
2Manufacturing precision
If existing mobility compensation methods are applied, then some improvement in luminance uniformity is achieved, but the compensation range is limited and current per pixel remains mismatched
Solution Approach 1:
The patent applies parameter changes by measuring multiple transistor characteristics including threshold voltage, mobility, and their deviations, then using these varied parameters to calculate comprehensive compensation values. The system adjusts compensation based on actual measured values rather than fixed assumptions, enabling accurate compensation across a wider range of device variations and maintaining proper current per pixel.
3Device complexity
If no compensation is applied, then device complexity remains low, but luminance non-uniformity and mura occur
Solution Approach 1:
The patent applies segmentation by dividing the compensation process into distinct functional modules: a measurement unit that characterizes individual transistors, a calculation unit that determines compensation values based on measured characteristics, and a control unit that applies compensation to pixel driving signals. This modular approach manages complexity systematically while achieving uniform luminance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution improves image quality by preventing luminance non-uniformity and deviation, allowing for real-time detection and compensation of OLED deterioration, achieving desired luminance and black levels, and expanding the mobility error compensation range.
Implementation Method 1
the OLED display using an organic light emitting diode (OLED) generating light by a recombination of electrons and holes
Data Source
AI summary
An organic light emitting diode display that includes pixels having organic light emitting diodes and driving transistors for supplying a driving current to the respective organic light emitting diodes. Also included is a compensator for receiving a predetermined voltage applied to a gate electrode of the respective driving transistors, finding a threshold voltage, mobility, and a change of mobility of the driving transistors, and determining a compensation amount caused by an input image data signal while sinking a predetermined current to a path of a driving current to the organic light emitting diode through a data line connected to the pixels. Further included is a timing controller for receiving the compensation amount, correcting the input image data signal, and transmitting the corrected image data signal and a data driver for generating a data voltage based on the corrected image data signal, and supplying the data voltage to the pixels.