Pixel Initialization Voltage Ramping for Low-Frequency Flicker Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
When the driving frequency of pixels in a display device changes from high to low frequency, hysteresis properties of the pixels change, leading to luminance differences that can cause a visually recognizable flicker phenomenon.
Innovation Solution
A display device design that includes a light emitting element, transistors, and capacitors, where the initialization voltage gradually decreases when converting from a high to a low frequency, with specific scan signals applied at different frequencies to manage hysteresis changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the driving frequency is converted from high frequency to low frequency, then the luminance of pixels increases, but a flicker phenomenon occurs due to large hysteresis property changes
Solution Approach 1:
The patent applies preliminary action by gradually decreasing the initialization voltage over multiple frames before the full low frequency operation begins. This gradual voltage reduction prepares the pixel circuit in advance, allowing the hysteresis properties to adjust progressively rather than experiencing a sudden large change, thereby preventing the flicker phenomenon while maintaining the desired luminance increase.
Solution Approach 2:
The patent implements dynamics by making the initialization voltage a variable parameter that changes over time rather than a fixed value. The voltage is dynamically adjusted across multiple frames during the frequency transition period, allowing the system to adapt to the changing hysteresis properties of the pixel circuit and eliminate the flicker effect.
2Object-affected harmful factors
If the initialization voltage is suddenly decreased to reduce flicker, then the luminance difference is reduced, but the image quality deteriorates
Solution Approach 1:
The patent uses dynamic adjustment of the initialization voltage across multiple frames rather than a sudden static change. This gradual dynamic reduction allows the pixel circuit to adapt smoothly, maintaining image quality while reducing the luminance difference that causes flicker.
Solution Approach 2:
The patent applies periodic action by implementing the voltage reduction over multiple discrete frames in a step-by-step manner. Each frame contributes to the gradual voltage decrease, creating a periodic adjustment pattern that maintains image quality while achieving the desired reduction in luminance difference.
Data Source
AI summary
A display device includes: a light emitting element including an anode and a cathode; a first transistor connected to the anode and a power line, and switchable by a voltage of a first node; a second transistor connected to a data line and a second node, and switchable by a write scan signal; a capacitor connected to the first node and the second node; an initialization transistor connected to the anode and an initialization line configured to receive an initialization voltage, and switchable by a bias scan signal, where the write scan signal is applied to the second transistor at a first frequency and a second frequency lower than the first frequency. When converting from the first frequency to the second frequency, in a k-th frame of the second frequency, a level of the initialization voltage may gradually decrease.