OLED Pixel Circuit Compensation for Luminance Degradation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional organic light emitting display devices face issues with maintaining desired image luminance due to the deterioration of organic light emitting diodes over time, leading to reduced light emission.
Innovation Solution
Incorporation of a dummy organic light emitting diode and a compensator between the organic light emitting diode and the dummy diode, which adjusts the gate voltage of the second transistor based on the difference in threshold voltages to compensate for the deterioration, ensuring consistent light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pixel circuit is used, then device complexity is low, but luminance stability deteriorates due to OLED deterioration
Solution Approach 1:
The patent introduces a dummy OLED that copies the structure and electrical characteristics of the real OLED but does not emit light. This dummy OLED serves as a reference for threshold voltage compensation, allowing the pixel circuit to track and compensate for OLED deterioration without adding complex external control mechanisms.
Solution Approach 2:
The patent introduces a compensator as an intermediary component between the real OLED and the dummy OLED. This compensator measures the threshold voltage difference between the two OLEDs and adjusts the gate voltage of the driving transistor accordingly, mediating the compensation process and maintaining luminance stability without requiring complex external control systems.
2Productivity
If OLED operates continuously, then productivity is high, but OLED deteriorates faster reducing duration of action
Solution Approach 1:
The patent implements a feedback mechanism where the compensator continuously monitors the threshold voltage of the driving transistor by comparing the real OLED and dummy OLED characteristics. This feedback allows the pixel circuit to dynamically adjust the gate voltage to compensate for OLED deterioration, enabling continuous operation while extending the effective display lifespan.
Solution Approach 2:
The patent performs preliminary compensation by using the dummy OLED to predict and prepare for threshold voltage drift before it significantly impacts display performance. The compensator proactively adjusts the gate voltage based on the threshold voltage difference, preventing luminance degradation rather than correcting it after it occurs.
3Reliability
If compensation mechanism is added, then luminance stability improves, but device complexity increases
Solution Approach 1:
The patent merges the compensation function with the existing pixel circuit structure by integrating the compensator and dummy OLED into the conventional pixel architecture. The compensator is coupled between the real and dummy OLEDs, and the threshold voltage compensation is achieved by adjusting the gate voltage of the existing driving transistor, combining multiple functions into a unified circuit design.
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 effectively compensates for the degradation of organic light emitting diodes by adjusting the current supplied to the organic light emitting diode, maintaining desired luminance levels and extending the device's operational lifespan.
Implementation Method 1
An organic light emitting display device displays images using organic light emitting diodes that emit light through recombination of electrons and holes
Data Source
AI summary
A pixel for an organic light emitting diode display is disclosed. The pixel includes an organic light emitting diode, a dummy organic light emitting diode, and a compensator configured to change the current received by the organic light emitting diode according to the difference in threshold voltages of the organic light emitting diode and the dummy organic light emitting diode.