OLED Degradation Compensation via Current Sensing
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Solution Overview
Problem
Organic light-emitting display devices face issues with image brightness due to OLED degradation over time, leading to reduced light emission at the same data signal levels, affecting image quality.
Innovation Solution
An organic light-emitting display device and method that calculates OLED degradation by measuring currents in degraded and non-degraded pixels, using a degradation determiner, current sensor, and degradation calculator to apply compensation data and maintain image brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If OLED is used in display pixels, then fast response time and low power consumption are achieved, but brightness decreases over time due to degradation
Solution Approach 1:
The patent implements a feedback mechanism where the display device measures current values from pixels and uses this information to calculate degradation amounts. The degradation calculator continuously monitors current changes and provides feedback to the degradation compensator, which then adjusts driving signals to compensate for OLED degradation and maintain consistent brightness over time.
Solution Approach 2:
The patent changes the driving parameters dynamically by calculating degradation amounts based on current measurements and using these degradation values to adjust the driving signals sent to OLED pixels. This parameter adjustment compensates for the brightness decrease caused by degradation, allowing the system to maintain desired brightness levels despite the natural aging of the OLED material.
2Illumination intensity
If degradation compensation is implemented, then brightness consistency is improved, but device complexity increases
Solution Approach 1:
The patent makes existing components serve multiple functions. The current sensor, originally designed to measure current for normal display operation, is also used to measure degradation by comparing current values over time. The degradation calculator uses the same current measurement data to compute degradation amounts and generate compensation values, eliminating the need for separate dedicated degradation measurement hardware.
Solution Approach 2:
The display device compensates for its own degradation using its existing operational components. The system uses its own current sensing capability and processing units to measure degradation and generate compensation signals, rather than requiring external degradation monitoring equipment or separate compensation hardware systems.
3Measurement precision
If current measurement is performed to calculate degradation, then degradation amount is determined accurately, but noise in measurement affects precision
Solution Approach 1:
The patent performs current measurement not only for normal display operation but also specifically for degradation assessment by applying test signals to pixels. This excessive measurement action allows the system to gather sufficient data points and statistical information to distinguish true degradation signals from noise, improving measurement precision through redundant sampling.
Solution Approach 2:
The patent creates a reference model of expected current values for non-degraded pixels and uses this copied expectation to compare against actual measurements. By establishing a theoretical copy of the ideal current characteristic and comparing real measurements against this reference, the system can filter out noise and identify true degradation patterns more accurately.
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
Compensates for OLED degradation without initial data, reducing noise effects and ensuring consistent image brightness by calculating and applying compensation data to degraded pixels.
Implementation Method 1
Organic light-emitting display devices use an organic compound that emits light display an image by using an organic light-emitting diode that generates light through recombination between electrons and holes
Implementation Method 2
a current sensor configured to apply a sensing voltage to the OLED and to measure a current corresponding to the sensing voltage
Data Source
AI summary
An organic light-emitting display device includes: a display panel comprising a plurality of pixels, wherein each of the plurality of pixels comprises an organic light-emitting diode (OLED) configured to emit light of one color from among a plurality of colors comprising red, green, and blue; a degradation determiner configured to determine a degree of degradation of the OLED from a value of accumulated image data that is input to each of the plurality of pixels; a current sensor configured to apply a sensing voltage to the OLED and to measure a current corresponding to the sensing voltage; and a degradation calculator configured to calculate an amount of degradation of the OLED from the current measured by the current sensor.