Light-Transmissive Electrode Films for Flexible Electro-Optic Devices

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Solution Overview

Problem

Existing electro-optic devices face issues such as increased manufacturing costs, higher voltage and energy consumption, reduced operational temperature range, decreased switching speed, and poor electro-optic performance due to the presence of an adhesive layer between the front and back electrodes, as well as defects or voids in the electro-optic material layer.

Innovation Solution

The electro-optic device eliminates the need for an adhesive layer between the front and back electrodes, using a conductive film with a first adhesive layer and a first electrode layer that does not conform to the surface roughness of the electro-optic material layer, ensuring good electro-optic performance even with defects or voids, and allowing for flexible and light-transmissive designs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If an adhesive layer is used between front and back electrodes, then manufacturing is simplified, but electro-optic performance deteriorates due to increased voltage and energy consumption

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidelectro-optic performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent removes the adhesive layer from the device structure entirely. The conductive film is designed to directly contact the electro-optic material layer without requiring an adhesive layer between electrodes, thereby eliminating the harmful electrical insulation barrier while maintaining manufacturing simplicity through direct lamination processes

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The conductive film serves as a dual-function intermediary element that simultaneously provides electrical conductivity and mechanical adhesion. By integrating adhesive properties into the conductive film itself rather than using a separate adhesive layer, the patent eliminates the electrical insulation problem while maintaining bonding capability

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If an adhesive layer is present between electrodes, then assembly is facilitated, but switching speed decreases and operational temperature range is reduced

Engineering Contradiction:
Improveassembly facilitationVSAvoidswitching speed
Core Design Contradiction:
Ease of manufactureVSSpeed

Solution Approach 1:

The adhesive layer is completely removed from the device structure. The conductive film directly contacts the electro-optic material layer, eliminating the insulation barrier that caused slow switching and limited temperature operation, while assembly is maintained through direct lamination or bonding processes

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If a conductive film does not conform to surface roughness, then electro-optic performance is maintained, but manufacturing precision requirements increase

Engineering Contradiction:
Improveelectro-optic performanceVSAvoidsurface conformality
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The conductive film is designed with differentiated surface properties: the portion contacting the electro-optic material layer is made smooth and planar to ensure good optical contact and prevent voids, while the adhesive portion maintains bonding capability. This local differentiation allows non-conformal surfaces to achieve good electro-optic performance by ensuring the critical optical interface is smooth regardless of underlying surface roughness

Inventive Principle:
Principle #3Local quality

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 configuration maintains optimal electro-optic performance, reduces manufacturing costs, and enhances flexibility while minimizing electrical shorts and defects, thus improving the overall efficiency and durability of the device.

Implementation Method 1

The conductive film may be light-transmissive

Methodology Applied
Scientific EffectLight transmission: Light

Implementation Method 2

a first adhesive layer and a first electrode layer

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP4081860B1Transferable light-transmissive electrode films for electro-optic devices
Publication Date: 2026.02.11 E INK CORP
  • EP4081860B1 patent drawingFigure 1~2
  • EP4081860B1 patent drawingFigure 3A
  • EP4081860B1 patent drawingFigure 3B

AI summary

An electro-optic device, and its method of manufacturing, is disclosed comprises a first substrate layer, a conductive film comprising a first adhesive layer and a first electrode layer, an electro-optic material layer, and a second electrode layer. The first electrode layer, which is on contact with the electro-optic material layer, comprises a conductive material, such as conductive particles, a metallic material or a conductive polymer. The first adhesive layer has high storage modulus and does not exhibit plastic flow under the conditions of manufacturing, storage, and operation of the electro-optic device. The conductive film does not conform to the surface roughness of the first surface of the electro-optic material layer. The conductive film may be designed to be thin, flexible and transparent. The resulting electro-optic device exhibit excellent electro-optic performance even where the electro-optic material layer has imperfections in the form of gaps.