Electrophoretic Display Driving Waveform for Gray Level Control
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Solution Overview
Problem
Existing electrophoretic display technologies face challenges in accurately controlling gray levels due to historical dependency and residual voltage, leading to errors in image representation and potential damage from improper DC balance during gray level adjustments.
Innovation Solution
A method and system for driving electrophoretic displays that involves determining a driving waveform based on initial and final gray levels, ensuring DC balance by changing gray levels through extreme optical states, and using a processing unit and driving control circuit to apply specific voltage pulses to pixel electrodes, allowing for accurate gray level control while maintaining DC balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If direct driving with look-up table is used to control gray levels, then the driving process is simple, but the gray level control accuracy deteriorates due to historical dependency and residual voltage
Solution Approach 1:
The patent segments the gray level control process into multiple driving procedures, each corresponding to a specific gray level changing direction. Instead of using a single direct driving approach with look-up table, the method divides the control into sequential steps that account for historical dependency, thereby improving accuracy while maintaining operational feasibility
Solution Approach 2:
The patent applies preliminary action by determining the driving waveform based on both initial and final gray levels before actual driving occurs. This preliminary determination ensures that the driving process compensates for residual voltage and historical dependency effects, achieving accurate gray level control without requiring complex real-time adjustments
2Stability of the object's composition
If gray level control is maintained for a long period, then the display stability is improved, but the error accumulates and increases due to inability to return to extreme optical state
Solution Approach 1:
The patent implements periodic action by incorporating extreme optical state transitions into the gray level control process. By periodically returning to extreme states (black or white), the system resets accumulated errors while maintaining display stability during intermediate states, thus preventing error accumulation over time
Solution Approach 2:
The patent uses feedback mechanisms by monitoring the current gray level state and adjusting the driving waveform accordingly. The system determines whether the final gray level is gradually changing in the current direction and adjusts the driving procedure to prevent error accumulation, ensuring both stability and accuracy are maintained
3Adaptability or versatility
If DC balance is not maintained during gray level control, then the control flexibility is improved, but the electrode and display medium may be damaged
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the driving waveform parameters based on the initial and final gray levels. This allows the system to maintain DC balance while adapting to different gray level transitions, thus preserving both control flexibility and component safety through optimized voltage application
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 enables precise control of gray levels and maintains DC balance, reducing errors and preventing electrode damage, thereby enhancing the accuracy and reliability of electrophoretic display technology.
Implementation Method 1
presents display effect of different colors using colored charged particles moving in a liquid environment by means of an external electric field
Implementation Method 2
determining a driving waveform of the electrophoretic display based on the initial gray level and the final gray level of a pixel, applying a display signal of the driving waveform to the pixel electrode
Data Source
AI summary
The present invention discloses an electrophoretic display and a driving met hod thereof, comprising: arranging each pixel electrode in the electrophoretic display to correspond to a pixel; determining a driving waveform of the electrophoretic display based on the initial gray level and the final gray level of the pixel, applying a display signal of the driving waveform to the pixel electrode, controlling the pixel whose gray level value needs to be changed; wherein the driving waveform comprises at least one gray level driving procedure, each driving procedure corresponds to a gray level changing direction, the final gray level is a gradually changing gray level in the gray level changing direction which the last driving procedure corresponds to. The present invention can realize relatively accurate control to the gray level change while keeping DC balance by means of the electrophoretic display and the driving method thereof when the screen is refreshed.