Electrowetting Element Voltage Control for Hysteresis
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Solution Overview
Problem
Electrowetting display devices suffer from hysteresis issues, leading to inconsistent display effects due to the difference in behavior when voltage is increased versus decreased, which affects the reliability of grayscale reproduction.
Innovation Solution
A method is introduced where the control system configures the voltage signal level throughout the display period to ensure that both fluids always adjoin the surface, overcoming the hysteresis effect by initiating the display element with a pre-display signal level that meets or exceeds the voltage threshold, allowing for consistent grayscale display states without an off state during the display period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If AC modulation is used to deal with hysteresis, then hysteresis effects are reduced, but power consumption increases due to requiring twice the operating voltage
Solution Approach 1:
A pre-display signal is applied before the display period to initiate the display element and overcome hysteresis effects in advance. This preliminary action ensures the electrowetting element is properly activated before grayscale display begins, eliminating the need for continuous AC modulation and reducing power consumption.
Solution Approach 2:
The patent changes the voltage parameter configuration by using a pre-display signal level that meets or exceeds the voltage threshold, then maintains the display element in an initiated state throughout the display period. This parameter change from transient AC modulation to sustained DC voltage with preliminary activation reduces power consumption while maintaining display consistency.
2Reliability
If the display element is driven from an off state, then hysteresis effects occur requiring threshold voltage to be overcome, but driving continuously in an on state eliminates hysteresis interference
Solution Approach 1:
The display element is maintained in a continuous on state throughout the display period, with the control system configuring the voltage signal level to ensure both fluids always adjoin the surface. This continuous activation eliminates hysteresis interference and ensures consistent grayscale reproduction without requiring complex off-state management.
Solution Approach 2:
A pre-display signal is applied before the display period to initiate the display element and overcome hysteresis effects in advance. This preliminary action ensures the electrowetting element is properly activated before grayscale display begins, eliminating the need for continuous AC modulation and reducing power consumption.
3Ease of operation
If pulse width modulation is used to achieve grayscale, then display states can be controlled, but hysteresis still affects optical performance
Solution Approach 1:
The patent changes the fundamental operating parameter from pulse width modulation (temporal control) to continuous voltage level control with preliminary activation. By maintaining the display element in a continuous on state and using voltage signal level configuration, the system achieves grayscale control without hysteresis interference, improving optical performance consistency.
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 reliable and consistent grayscale display states, improving image quality and eliminating hysteresis interference, while using direct current voltage reduces power consumption and simplifies signal sequences.
Implementation Method 1
Electrowetting display devices are known. Hysteresis may be observed in electrowetting display devices.
Data Source
AI summary
A method of controlling an electrowetting element. The method includes receiving first data indicative of a first display effect. Using the first data, a first magnitude of a first voltage is determined. The first voltage with the first magnitude is generated and applied to the electrowetting element. Second data indicative of a second display effect different from the first display effect is received. Using the second data, a second magnitude of a second voltage is determined. The second magnitude is equal to the first magnitude. The second voltage with the second magnitude is generated and applied to the electrowetting element.