OLED Pixel Circuit With Photosensitive Capacitor for Sunlight Stability
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Solution Overview
Problem
OLED display panels suffer from screen flickering and color cast under sunlight due to changes in light intensity affecting the driving current and brightness stability.
Innovation Solution
Incorporating a photosensitive capacitor with varying capacitance values based on light intensity to stabilize the gate potential of the driving transistor, reducing brightness fluctuations and color cast by maintaining consistent driving current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional OLED display panel is used, then the display panel achieves high visibility and high brightness, but it suffers from screen flickering and color cast under sunlight
Solution Approach 1:
The patent applies parameter changes by using a photosensitive capacitor whose capacitance value changes in response to light intensity. Under strong sunlight, the capacitance increases to compensate for the driving current reduction caused by light-induced threshold voltage changes in the transistor, thereby maintaining stable brightness and eliminating flickering and color cast phenomena.
2Illumination intensity
If light intensity increases, then the display panel brightness increases, but the driving current changes causing flickering and color cast
Solution Approach 1:
The patent implements feedback by using the photosensitive capacitor to sense light intensity changes and automatically adjust the gate voltage of the driving transistor. The capacitor's capacitance changes with light intensity, creating a feedback mechanism that compensates for light-induced current variations and maintains stable driving current composition regardless of external lighting conditions.
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
Enhances brightness stability and reduces flickering and color cast issues under varying light conditions, ensuring stable display performance.
Implementation Method 1
the photosensitive capacitor has a first capacitance value under a first light intensity and a second capacitance value under a second light intensity; the first light intensity is less than the second light intensity; and the first capacitance value is less than the second capacitance value
Data Source
AI summary
A display panel and a display device are provided. The display panel includes a pixel circuit and a light-emitting element electrically connected to the pixel circuit. The pixel circuit includes a driving transistor and a photosensitive capacitor. The driving transistor is configured to provide a driving current to the light-emitting element; the photosensitive capacitor includes a first electrode electrically connected to a gate of the driving transistor; and a second electrode electrically connected to a first signal line. The first signal line is configured to transmit a first voltage signal; the first voltage signal is a constant voltage signal; the photosensitive capacitor has a first capacitance value under a first light intensity and a second capacitance value under a second light intensity; the first light intensity is less than the second light intensity; and the first capacitance value is less than the second capacitance value.