Electrophoretic Display Microcups Segmented Partition Wall

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Solution Overview

Problem

In electrophoretic displays, defects in the partition wall between microcups can cause fluid to move between adjacent cells, leading to visual defects, and reducing microcup size to minimize these defects lowers the fill factor and optical performance.

Innovation Solution

The design features microcups of different shapes, where one shape is surrounded by another that is 90% or less in area, and includes double walls with bridges between layers to prevent fluid leakage, maintaining the fill factor and reducing defect visibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the partition wall between microcups is made thinner to increase fill factor, then the fill factor improves, but defects in the partition wall become more noticeable and fluid can move between adjacent cells

Engineering Contradiction:

Improvefill factorVSAvoidpartition wall integrity

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The partition wall is divided into multiple segments (first partition wall portion and second partition wall portion) that are separated by a gap. This segmentation prevents fluid communication between adjacent microcups even when the overall wall thickness is reduced to increase fill factor, as the gap acts as a barrier to fluid flow while allowing the wall to be thinner.

Inventive Principle:

Principle #1Segmentation

2Object-affected harmful factors

If the microcup size is reduced to minimize defect visibility, then defect visibility decreases, but the fill factor and optical performance are lowered

Engineering Contradiction:

Improvedefect visibilityVSAvoidfill factor

Core Design Contradiction:

Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

Instead of reducing microcup size in two dimensions, the solution addresses defect visibility by modifying the vertical dimension through the segmented partition wall structure. The gap between wall portions creates a visual and functional barrier that reduces defect visibility while allowing microcups to maintain their original size and fill factor.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If the partition wall is made single-layer to simplify manufacturing, then manufacturing complexity decreases, but fluid can leak between adjacent microcups through defects

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidfluid containment

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The partition wall is segmented into multiple portions with a gap between them, creating a multi-chamber structure that prevents fluid leakage. This segmentation provides redundant barriers against fluid communication, enhancing reliability without requiring a completely separate dual-wall structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The segmented partition wall portions are nested within the same microcup structure, with each portion forming a barrier layer. The gap between portions creates a nested barrier system that prevents fluid leakage while maintaining structural integration within the microcup array.

Inventive Principle:

Principle #7Nested doll (Nesting)

Data Source

PatentUS9291872B1Electrophoretic display design

Publication Date: 2016.03.22 E INK CORP

AI summary

The present invention is directed to electrophoretic displays comprising microcups of a first shape and the microcups of a second shape, wherein each of the microcups of the first shape is surrounded by the microcups of the second shape, and the second shape is 90% or less of the first shape in area. The present electrophoretic displays comprise novel microcup designs, which may reduce the appearance of defects in the display images.