OLED Display Voltage Control for Halo Phenomenon
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Solution Overview
Problem
Organic light-emitting display devices face issues with the halo phenomenon and display quality, where luminance differences occur due to varying degrees of degradation in transistors across different areas of the display, leading to uneven brightness and reduced contrast ratio.
Innovation Solution
An organic light-emitting display device with a timing controller that calculates the black bias pixel ratio (BBPR) and adjusts the driving voltage based on this ratio, switching between a first and second driving mode to prevent halo phenomena and improve display quality by applying appropriate voltages to the OLEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constant driving voltage is applied to the display unit, then the device structure is simple and power consumption is low, but the halo phenomenon occurs due to transistor degradation and display quality deteriorates
Solution Approach 1:
The patent applies dynamic voltage adjustment by switching between first and second driving voltages based on the black bias pixel ratio (BBPR). The power supply unit dynamically changes the driving voltage applied to the display unit according to the calculated BBPR value, transforming the static voltage application into a dynamic adaptive process that prevents halo phenomenon while maintaining display quality.
Solution Approach 2:
The patent changes the driving voltage parameter based on the BBPR calculation. By adjusting the voltage level (switching between first and second driving voltages) according to the black bias pixel ratio, the system adapts to varying display conditions and prevents transistor degradation-induced halo effects without requiring complex per-pixel control.
2Reliability
If a high driving voltage is continuously applied to prevent transistor degradation, then display quality is maintained, but power consumption increases
Solution Approach 1:
The patent implements periodic voltage adjustment based on the BBPR calculation. Instead of continuously applying high voltage, the system periodically evaluates the BBPR and switches between first and second driving voltages accordingly. This periodic action maintains transistor reliability when needed while reducing power consumption during normal operation.
Solution Approach 2:
The patent dynamically changes the driving voltage parameter based on BBPR to balance reliability and power consumption. By adjusting the voltage level according to actual display conditions rather than maintaining a constant high voltage, the system prevents transistor degradation only when necessary, thereby reducing overall power consumption.
3Manufacturing precision
If different voltages are applied to different pixel units to compensate for degradation, then display uniformity is improved, but device complexity and power consumption increase significantly
Solution Approach 1:
The patent applies local quality adjustment through BBPR-based voltage control. Instead of implementing complex per-pixel voltage adjustment, the system calculates the overall BBPR and applies a unified voltage adjustment to the entire display unit. This approach achieves display uniformity by addressing the root cause (black bias conditions) rather than individually compensating each pixel, thereby avoiding excessive complexity.
Solution Approach 2:
The patent uses a universal voltage control approach where a single BBPR calculation governs the driving voltage for all pixel units. The timing controller and power supply unit work together to apply a unified voltage adjustment that benefits the entire display, eliminating the need for complex individual pixel control circuits while maintaining display uniformity.
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 effectively reduces the degree of degradation in transistors, preventing the halo phenomenon and enhancing display quality by ensuring consistent luminance across the display, thereby improving contrast ratio and reducing power consumption.
Implementation Method 1
organic light-emitting display devices display an image using light-emitting diodes (OLEDs), which generate light through the recombination of electrons and holes
Data Source
AI summary
An organic light-emitting display device includes a display unit having a plurality of pixel units. The display device also includes a timing controller for calculating a black bias pixel ratio (BBPR) of the display unit based on image signals provided by an external source and for generating a control signal based on the BBPR. The BBPR is the ratio of a number of pixel units in a black state to a total number of pixel units. A power supply unit provides a driving voltage to the display unit based on the control signal from the timing controller, wherein the power supply unit provides a first driving voltage to the display unit when the BBPR is less than a reference value and provides a second driving voltage, which is higher than the first driving voltage, otherwise.