Electrophoretic Display Gray Scale Control Using Effective Drive Compensation
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Solution Overview
Problem
The non-linear relationship between driving duration and gray scale in electronic paper makes rapid and accurate adjustment of gray scale difficult due to temperature and historical factors.
Innovation Solution
An electrophoretic display panel with a driving method that calculates a required driving waveform based on specific equations, adjusting gray scale by determining a target effective drive using formulas that minimize the difference between theoretical and actual drives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PWM mode is used to control gray scale, then energy saving and display persistence are achieved, but the non-linear relationship between driving duration and gray scale makes rapid and accurate adjustment difficult
Solution Approach 1:
The patent introduces a compensation parameter δ that modifies the driving duration to account for non-linear effects. By changing the parameter from simple PWM duty cycle to adjusted duration (T - δ), the system compensates for temperature and historical factors, achieving accurate gray scale control without complex real-time calculations.
Solution Approach 2:
The patent implements feedback through the compensation parameter δ, which is determined based on previous driving results and current conditions. This feedback mechanism allows the system to learn from past performance and adjust future driving durations, achieving accurate gray scale control while maintaining simple PWM architecture.
2Measurement precision
If driving duration is extended to improve gray scale accuracy, then measurement precision improves, but the time required for calibration and testing increases
Solution Approach 1:
The patent performs preliminary characterization of the electrophoretic display panel to obtain the compensation parameter δ. This preliminary action is done once during manufacturing or initial calibration, allowing the system to use pre-determined parameters for subsequent operation, thereby avoiding time-consuming repeated calibration during normal use.
Solution Approach 2:
The patent creates a lookup table or characteristic curve that stores pre-calculated compensation values for different gray levels and conditions. During operation, the system queries this pre-computed data rather than performing real-time complex calculations, significantly reducing calibration time while maintaining 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
Improves the speed and accuracy of gray scale adjustment, reducing calibration difficulties in electrophoretic display panels.
Implementation Method 1
The principle of the electronic paper is to use the electrophoresis of charged particles, that is, two anisotropic charged particles move to the two electrodes of the display under the driving of the electric field
Data Source
AI summary
Provided denotes an electrophoretic display panel, a driving method of the electrophoretic display panel, and a display device. The electrophoretic display panel includes a data lines and a pixels, the data lines is configured to transmit a data signal to the pixels, and the data signal includes multiple unit periods. In a driving stage, in an i-th unit period ti, a unit driving voltage of the data signal is Vi, a target effective drive is Vm, and Vm=ΣViti is satisfied, where i is a positive integer. A theoretical effective drive satisfies at least one of following equations: in an equation (1), when a target gray scale is fixed,Vl=64nAx+B,where 0.23<A<0.29, and −20<B<10; in an equation (2), when an initial gray scale is fixed,Vl=64nCy+D,where −0.22<C<−0.10, and 0<D<25.