Retroreflective Electro-Optic Display for High Contrast

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Solution Overview

Problem

Conventional electro-optic displays face challenges in providing high contrast and low power consumption while maintaining visibility and durability, especially in applications requiring wide viewing angles and flexibility.

Innovation Solution

An electro-optic display comprising a layer of electro-optic medium that switches between open and closed states with an electric field, combined with a retro-reflector layer and light-transmissive electrodes, allowing for variable light transmission and reflection, and optionally incorporating colored materials or color filter arrays for enhanced contrast.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If conventional electro-optic displays are used, then power consumption is reduced, but contrast ratio and visibility deteriorate

Engineering Contradiction:

Improvepower consumptionVSAvoidcontrast ratio

Core Design Contradiction:

Use of energy by moving objectVSIllumination intensity

Solution Approach 1:

The patent combines retro-reflective elements with the electro-optic display structure, merging the functions of light reflection and electro-optic modulation in a single integrated system. This allows the display to utilize ambient light effectively while maintaining low power consumption for the electro-optic layer only.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The retro-reflective layer acts as an intermediary that captures and redirects ambient light through the electro-optic medium to the viewer, enabling high contrast without requiring continuous power input to the display system.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If conventional electro-optic displays are used, then power consumption is low, but viewing angle and flexibility deteriorate

Engineering Contradiction:

Improvepower consumptionVSAvoidviewing angle

Core Design Contradiction:

Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The patent employs flexible substrate materials and thin-film construction for the display layers, enabling the display to be bent or conform to curved surfaces while maintaining electro-optic functionality and wide viewing angles through the retro-reflective optical path.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The retro-reflective structure introduces a new optical dimension by reflecting light back through the electro-optic layer, creating a bidirectional light path that expands the effective viewing angle beyond conventional unidirectional display geometries.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Illumination intensity

If retro-reflective elements are added to enhance visibility, then contrast and viewing angle improve, but device complexity increases

Engineering Contradiction:

Improvecontrast ratioVSAvoidstructure complexity

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The retro-reflective elements are integrated directly into the display stack as a combined structure, eliminating the need for separate auxiliary lighting systems or complex optical assemblies, thereby reducing overall device complexity while maintaining enhanced visibility.

Inventive Principle:

Principle #5Merging (Combining)

4Illumination intensity

If retro-reflective elements are added to enhance visibility, then contrast and viewing angle improve, but manufacturing difficulty increases

Engineering Contradiction:

Improvecontrast ratioVSAvoidmanufacturing ease

Core Design Contradiction:

Illumination intensityVSEase of manufacture

Solution Approach 1:

The use of flexible thin-film retro-reflective materials enables conventional coating and lamination manufacturing processes, avoiding complex precision assembly steps and facilitating scalable production while achieving the desired optical performance.

Inventive Principle:

Principle #30Flexible shells and thin films

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

The solution enables displays with high contrast, low power consumption, and wide viewing angles, suitable for applications like road signs and safety reflectors, while maintaining flexibility and durability.

Implementation Method 1

a layer comprising a plurality of retro-reflectors

Methodology Applied

Scientific EffectRetroreflection: Retroreflector

Implementation Method 2

a layer of an electro-optic medium capable of being switched between an open state and a closed state upon application of an electric field

Methodology Applied

Scientific EffectElectro-optic effect: Electro-Optic Effects

Data Source

PatentUS11402719B2Retroreflective electro-optic displays

Publication Date: 2022.08.02 E INK CORP

AI summary

An electro-optic display includes a first light-transmissive electrode, a layer of an electro-optic medium capable of being switched between an open state and a closed state upon application of an electric field, a second light-transmissive electrode, and a layer having a plurality of retro-reflectors.