OLED Display Degradation Compensation via Sensing Unit
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Solution Overview
Problem
Organic light emitting diodes (OLEDs) in displays degrade quickly under voltage regulation drive, leading to reduced luminance and inability to display desired images due to increased resistance, which reduces the electric current flowing through them.
Innovation Solution
An organic light emitting display with a sensing unit that supplies a first current to OLEDs during a sensing period to convert applied voltage to digital values and adjusts a second current during a sampling period to compensate for degradation, using a current source, current digital-analog converter, switching units, and memory to maintain consistent electric current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If voltage regulation drive is applied to OLEDs, then luminance control is achieved, but degradation of OLEDs progresses faster
Solution Approach 1:
The patent implements a feedback mechanism by measuring the actual voltage across each OLED using a sensing unit, converting it to a digital value, and using this information to adjust the driving current. This closed-loop control allows the system to compensate for OLED degradation in real-time, maintaining reliable luminance output despite aging effects.
Solution Approach 2:
The patent changes the driving parameter from fixed voltage regulation to adaptive current control based on measured voltage characteristics. By measuring the voltage across each OLED and converting it to a digital value, the system adjusts the driving current dynamically, transforming the approach from static voltage control to adaptive parameter control that compensates for degradation.
2Power
If OLEDs operate under voltage regulation drive, then light emission control is enabled, but resistance increases causing reduced current flow
Solution Approach 1:
The sensing unit measures the actual voltage across each OLED and converts it to a digital value that reflects the OLED's resistance characteristics. This feedback information is used to adjust the driving current, ensuring that increased resistance due to degradation does not reduce the current flow and maintain reliable light emission control.
3Reliability
If sensing unit measures voltage and converts to digital values, then degradation compensation is enabled, but device complexity increases
Solution Approach 1:
The patent introduces a sensing unit as an intermediary component that measures voltage and converts it to digital values. This intermediary translates the physical voltage characteristic into a form that can be processed by the control logic, enabling degradation compensation without requiring direct complex control of the OLED itself.
Solution Approach 2:
The patent replaces direct electrical control mechanisms with a sensing and digital conversion system. Instead of directly controlling current based on complex electrical characteristics, the system uses voltage measurement and digital conversion to simplify the control approach, substituting direct electrical control with a measurement-and-response mechanism.
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 by adjusting the electric current, ensuring consistent luminance and image quality by converting voltage to digital values and storing them for adjusting the current sunk from pixels, thereby maintaining desired luminance levels.
Implementation Method 1
the organic light emitting display makes use of organic light emitting diodes that emit light by re-combination of electrons and holes
Data Source
AI summary
An organic light emitting display and a method for driving the same, which may compensate for the degradation of an organic light emitting diode. The organic light emitting display includes: a plurality of pixels, each including an organic light emitting diode and a pixel circuit for controlling a supply of an electric current to the organic light emitting diode; and a sensing unit for converting a voltage applied to the organic light emitting diode to a digital value during a sensing period, and for sinking a second current from the pixel corresponding to the digital value to compensate for a degradation of the organic light emitting diode during a sampling period.