Electrowetting Display Electrode Cut-Out for Fluid Initiation
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Solution Overview
Problem
Existing electrowetting display devices face challenges in controlling the motion of the first fluid due to a poorly defined initiation point, leading to variations in fluid motion between picture elements over time.
Innovation Solution
The electrode design includes a cut-out shape that deviates from the wall edge, with parts of the edge following the wall shape, creating a strong electric fringe field near the cut-out, which initiates the fluid motion preferentially at a well-defined location, improving control over fluid movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a high portion electrode is used to improve fluid motion control, then the electric field strength above the electrode increases, but the place of initiation of fluid motion becomes poorly defined and varies over time
Solution Approach 1:
The electrode design incorporates a cut-out in the high portion, creating a localized region with enhanced electric field concentration. This local modification to the electrode structure creates a specific zone where the electric field is strongest, providing a well-defined initiation point for fluid motion while maintaining the overall high field strength needed for effective fluid control
Solution Approach 2:
The cut-out in the electrode introduces a geometric feature that creates electric field fringing effects in the vertical dimension. This dimensional change in the electric field distribution creates a concentrated field region at specific locations around the cut-out, establishing precise initiation points for fluid motion that are consistent over time
2Area of stationary object
If the electrode edge follows the wall shape, then the electrode coverage is maximized, but the fluid motion initiation is not well-defined
Solution Approach 1:
The electrode design follows the wall shape in most areas to maximize coverage, but introduces a localized cut-out feature in the high portion. This local deviation from the wall-following pattern creates the necessary electric field concentration for well-defined fluid initiation while preserving the overall large electrode area for effective fluid control
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 design enhances the control and consistency of fluid motion, reducing hysteresis and threshold voltage, resulting in improved performance and stability across picture elements.
Implementation Method 1
an electrowetting display device with a plurality of scanning lines disposed on a lower substrate
Implementation Method 2
The cut-out in the electrode causes an electric fringe field when a voltage between the electrode and the second fluid is applied. The fringe field is relatively strong and has a relatively short range in the vicinity of the cut-out.
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
The present invention relates to an electrowetting display device (1) comprising at least one picture element (8) having a first support plate (2) and a second support plate (3) and a space (9) between the first support plate (2) and the second support plate (3), the space (9) including at least one first fluid (13) and a second fluid (14) immiscible with each other, the second fluid (14) being electroconductive or polar; the first support plate (2) including a wall (6) defining the extent of the picture element, the wall (6) having a shape, an electrode (15) for applying an electric field between the electrode and the second fluid (14), the electrode having an edge (28-35), a low portion (42) and a high portion (41), the high portion being closer to the second support plate than the low portion, the high portion being arranged adjacent to the wall and having an area smaller than the area of the low portion; the high portion of the electrode having a cut-out (37, 38, 39) causing an increased electric field in the space, and at least part of the edge (28, 29, 30, 31) of the electrode adjacent to the cut-out following the shape of the wall.