OLED Display Driving TFT Compensation Circuit for Stable Luminance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing organic light emitting display devices face challenges in achieving accurate and stable operation of driving transistors due to fluctuations in gate-source voltage caused by changes in high voltage levels, affecting luminance consistency.
Innovation Solution
Incorporation of a voltage compensation circuit and an on-bias stress voltage application to stabilize the gate-source voltage of driving transistors by reflecting voltage differences through capacitors and independent high voltage sources, minimizing fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high voltage is supplied to the driving TFT to enable current control for light emission, then the light emitting capability is improved, but voltage fluctuations occur affecting gate-source voltage stability
Solution Approach 1:
A compensation capacitor is introduced as an intermediary element between the high voltage source and the gate-source junction. This capacitor mediates the voltage transmission by storing charge during periods when the high voltage is stable and releasing it when voltage fluctuations occur, thereby isolating the gate-source voltage from direct high voltage variations while still enabling current control for light emission
2Measurement precision
If the gate electrode is connected to the second electrode during non-emission period for voltage determination, then data voltage input accuracy is improved, but voltage reflection from high voltage changes affects stability
Solution Approach 1:
The compensation capacitor is charged in advance during the non-emission period when the gate electrode is connected to the second electrode. By storing the voltage level information beforehand in the capacitor, the system prepares a stable voltage reference that cushions against subsequent high voltage fluctuations during the emission period, ensuring both accurate voltage determination and stability
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 enhances the accuracy and stability of driving transistor operations, maintaining consistent luminance despite variations in high voltage levels, thereby improving display quality.
Implementation Method 1
a voltage compensation circuit configured to reflect a difference between the first high voltage in the emission period and the first high voltage in the non-emission period in the gate electrode
Data Source
AI summary
A display device includes a light emitting element, a driving TFT including a first electrode, a second electrode connected to the light emitting element, and a gate electrode, wherein a voltage level of the gate electrode is determined according to a data voltage input to the first electrode while the gate electrode and the second electrode are connected in a non-emission period, the driving TFT being configured to receive a first high voltage through the first electrode to control a current applied to the light emitting element according to a voltage difference between the gate electrode and the first electrode while the gate electrode is disconnected from the second electrode in an emission period, and a voltage compensation circuit configured to reflect a difference between the first high voltage in the emission period and the first high voltage in the non-emission period in the gate electrode.