Variable Frame Time Driving Waveform for Electrophoretic Display Synchronization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Active matrix driving in electrophoretic displays results in non-synchronized image updating from the top to the bottom of the display panel, leading to non-uniformity and lag in pixel updating, particularly at transition time points.
Innovation Solution
A driving waveform with varying frame times, where driving frames at transition time points have a first frame time and the remaining frames have a second frame time, with the first frame time being a fraction of the second frame time, typically between 5% to 60% of it, to synchronize pixel and common electrode updates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If active matrix driving is used to drive electrophoretic display, then the display can be updated continuously, but the image updating becomes non-synchronized from top to bottom of the panel, causing non-uniformity and lag
Solution Approach 1:
The patent applies dynamics by making the frame time variable rather than fixed. Specifically, frame time is adjusted based on the position within the waveform: shorter frame times are used during transition phases and longer frame times during stable phases. This dynamic adjustment synchronizes the updating of pixels with the common electrode, eliminating the non-uniformity and lag caused by fixed frame timing in active matrix driving.
Solution Approach 2:
The patent changes the time parameter of the driving waveform by implementing variable frame times. The frame time is modified according to the operational phase: it is reduced during voltage transitions to minimize lag, and extended during stable states to maintain synchronization. This parameter change resolves the contradiction between continuous updating and synchronization uniformity.
2Manufacturing precision
If variable frame time is applied at transition time points, then synchronization and lag reduction are improved, but the waveform complexity increases
Solution Approach 1:
The patent segments the driving waveform into distinct phases: transition phases and stable phases. Each phase is assigned a specific frame time characteristic (shorter for transitions, longer for stable states). This segmentation allows precise control over when frame time varies, improving synchronization accuracy without requiring continuous complex adjustments throughout the entire waveform.
Solution Approach 2:
The patent implements periodic variation of frame time that aligns with the periodic nature of the driving waveform. The frame time is systematically adjusted at regular transition points rather than arbitrarily, creating a predictable and manageable waveform pattern that reduces complexity while maintaining synchronization accuracy.
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 approach minimizes voltage changes and shortens the overall driving time, reducing lag and non-uniformity, while maintaining similar power consumption and resolution, and can be applied to both mono-polar and bi-polar driving methods.
Implementation Method 1
An electrophoretic display (EPD) is a non-emissive device based on the electrophoresis phenomenon of charged pigment particles suspended in a solvent
Data Source
AI summary
The present invention is directed to driving waveforms and a driving method for an electrophoretic display. The method and waveforms have the advantage that the changes in the driving voltages due to the shift are minimized. In addition, the overall driving time for the waveforms is also shortened due to the shortened driving frames. There are no additional data points required as the number of the driving frames remains the same. Therefore, the power consumption is nearly identical with the waveform having driving frames of a fixed frame time.