OLED Display Voltage Modulation for Afterimage Reduction
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Solution Overview
Problem
Organic light-emitting diode (OLED) displays experience afterimages and luminance degradation due to prolonged carrier movement and impurity accumulation, which affects their performance and lifespan.
Innovation Solution
An OLED display that periodically changes the second power voltage level between reference voltage levels, adjusting the on-period length of emission signals and data signals to maintain optimal carrier movement and reduce impurity accumulation, while also adjusting the luminance of status display regions based on main display regions to prevent afterimages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the second power voltage level is kept constant, then the OLED display maintains stable operation, but carrier movement stagnation and impurity accumulation occur causing afterimages and luminance degradation
Solution Approach 1:
The patent applies periodic action by changing the second power voltage level (ELVSS) between a first reference voltage level and a second reference voltage level in periodic intervals. This periodic voltage modulation prevents carrier movement stagnation and impurity accumulation in the organic light-emitting layer, thereby reducing afterimages while maintaining overall operational stability through controlled voltage transitions.
2Reliability
If the second power voltage level is periodically changed, then carrier movement is optimized and impurity accumulation is reduced, but voltage level instability increases
Solution Approach 1:
The patent implements periodic action by systematically transitioning the second power voltage level between two reference voltage levels at defined intervals. This periodic modulation optimizes carrier transport and prevents impurity accumulation throughout the OLED's operational lifespan, with the controlled voltage changes extending device longevity despite the intentional voltage variations.
3Illumination intensity
If the on-period length of emission signals is adjusted, then luminance stability is maintained, but device complexity increases
Solution Approach 1:
The patent applies dynamics by dynamically adjusting the on-period length of emission signals based on the current second power voltage level. When the second power voltage level is at the first reference voltage level, the on-period is set to a first length; when at the second reference voltage level, the on-period is adjusted to a second length. This dynamic adjustment compensates for voltage-induced luminance variations, maintaining stable display brightness despite voltage modulations.
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
The solution reduces the occurrence of afterimages and extends the lifespan of OLED displays by minimizing carrier movement stagnation and impurity accumulation, while maintaining luminance stability across different grayscale levels.
Implementation Method 1
Positive holes from the anode electrode can be combined with electrons from the cathode electrode in the organic layer to emit light
Data Source
AI summary
An organic light-emitting diode display is disclosed. In one aspect, the display includes a display panel including a plurality of pixels, a scan driver configured to provide a scan signal to the pixels, and a data driver configured to provide a data signal to the pixels. The display also includes a power supply configured to provide first and second power voltages, respectively having first and second voltage levels, to the pixels, wherein the power supply is further configured to substantially periodically change the second voltage level, and wherein the second voltage level is less than the first voltage level. The display also includes a controller configured to control at least one of the scan driver, the data driver, and the power supply.