Electronic Paper Display Substrate with Equipotential Conductive Layer
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Solution Overview
Problem
Conventional electronic paper displays suffer from poor contrast between pixel and non-pixel regions due to the influence of fringe fields, resulting in monotonic colors and suboptimal display quality.
Innovation Solution
The manufacturing method involves forming a colored layer and transparent conductive thin films on a base substrate, with an equipotential conductive thin film covering the entire substrate to eliminate fringe fields, allowing the pixel electrode to have a predetermined pattern and improving contrast by displaying the color of the colored layer when electrified.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional pixel electrode structure is used, then the display can be manufactured with simple processes, but the contrast between pixel and non-pixel regions is poor due to fringe field influence
Solution Approach 1:
The pixel electrode is segmented into multiple regions with different potentials. The non-pixel region electrode is separated from the common electrode, creating independent potential zones. This segmentation eliminates fringe field interference at boundaries while maintaining simple manufacturing processes.
Solution Approach 2:
The non-pixel region electrode is connected to the common electrode through a conductive layer, creating an equipotential region. This eliminates potential differences at the pixel-non-pixel boundaries, removing the source of fringe fields that cause poor contrast.
2Ease of manufacture
If the display medium is PDLC film without polarization sheets, then the process is simplified and luminance is improved, but the displayed pattern has poor contrast with non-pixel region
Solution Approach 1:
Different regions of the display are given different electrical properties. The pixel region has controlled potential differences to activate PDLC film, while the non-pixel region maintains equipotential conditions to keep PDLC film in a stable state, creating local quality differences that improve contrast.
Solution Approach 2:
A conductive layer is introduced as an intermediary between the non-pixel region electrode and the common electrode. This intermediary ensures equipotential conditions in the non-pixel region without requiring complex structures or additional manufacturing steps.
3Device complexity
If fringe fields are present between pixel electrode and common electrode, then the conventional structure is maintained, but the display quality deteriorates
Solution Approach 1:
The fringe field effect, which is normally harmful to display quality, is eliminated by creating an equipotential non-pixel region. The simple conventional structure is retained, but the harmful fringe fields are converted into beneficial equipotential conditions through the conductive layer connection.
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 enhances the contrast between pixel and non-pixel regions, enabling the display of colorful patterns with improved luminance and performance by eliminating the interference from fringe fields and maintaining the display medium's state in non-pixel regions.
Implementation Method 1
The equipotential conductive thin film may be connected with the common electrode on the upper substrate to form an equipotential, so that there is no electric field between the non-pixel region and the common electrode.
Implementation Method 2
EC material may generate a reversible change between chromatic state of low transmittance and achromatic state of high transmittance by injecting or drawing charges (ions or electrons) under the effect of alternate high and low external field or alternate positive and negative external field.
Implementation Method 3
A PDLC film can present two different optical states of transmission and dispersion under the effect of external field, such as, alternating current field, heat field, and so on.
Data Source
AI summary
By forming a corresponding colored layer under the pixel electrode having a predetermined pattern of the electronic paper display substrate, the pattern displayed in the region where the pixel electrode and the colored layer is disposed has the color of the colored layer when displaying. Compared with the transparency color, the color of the colored layer can make the contrast of the pixel region to the non-pixel region high and display colorful pattern.