Multilayer Light Modulator Using Electrophoretic Particle Positioning

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Solution Overview

Problem

Existing light modulators lack the ability to control light intensity over a specified range of optical frequencies with high precision and efficiency, particularly in reflecting or absorbing light in a controllable manner.

Innovation Solution

A multilayer light modulator comprising optically reflecting, transmitting, and variable layers with electrophoretic particles in a fluid, where a bias generator adjusts the position of the particles to alter reflectance and refraction, enabling high specular reflectance or absorbance based on electrical control signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If liquid crystal modulators are used to modulate light intensity, then polarization rotation control is achieved, but the device requires a fixed polarizer and complex electric field control

Engineering Contradiction:
Improvelight modulation controlVSAvoidstructure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts and removes the fixed polarizer component from the light modulator system. By using electrophoretic particles that can be positioned to control light reflection and absorption directly, the need for a separate polarizer is eliminated, simplifying the overall device structure while maintaining light modulation functionality

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the liquid crystal polarization rotation mechanism with an electrophoretic particle positioning system. Instead of using electric fields to rotate polarization planes, the system uses electrophoresis to move particles that directly reflect or absorb light, substituting a mechanical particle positioning system for an optical polarization control system

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If electrochromic modulators are used with back reflectors, then light absorption and reflection control is achieved, but ions must pass through perforated mirrors increasing device complexity

Engineering Contradiction:
Improvelight absorption controlVSAvoidmirror structure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts and removes the back reflector component from the electrochromic modulator system. By using electrophoretic particles that can be positioned within the fluid layer to control light absorption and reflection, the need for a separate back reflector is eliminated, simplifying the device structure

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The electrophoretic particle system performs multiple functions simultaneously: it controls both light absorption and reflection, and it eliminates the need for separate components like back reflectors or perforated mirrors. The particles themselves provide the light control functionality that previously required multiple separate components

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If multilayer optical interference filters are used, then optical frequency control is achieved, but the device requires multiple fixed layers reducing adaptability

Engineering Contradiction:
Improveoptical frequency controlVSAvoidfrequency range adaptability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic adaptability to the light modulator by using electrophoretic particles that can be repositioned in response to control signals. This allows the device to dynamically adjust its optical properties across different frequencies, transforming a static multilayer filter system into a dynamic, adaptable system that can respond to varying optical conditions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent enables parameter changes by allowing the electrophoretic particles to change their position and distribution within the fluid layer in response to control signals. This changes the optical parameters of the device, allowing it to adapt to different frequency ranges and optical conditions without requiring physical reconfiguration of fixed layers

Inventive Principle:
Principle #35Parameter changes

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 multilayer light modulator achieves controlled light intensity modulation across a range of optical frequencies, providing high reflectance or absorbance with low power consumption and improved modulation efficiency compared to traditional modulators.

Implementation Method 1

The optically variable layers comprise a plurality of electrophoretic particles supported in a fluid. The bias generator creates a bias that changes the reflectance of the light modulating stack by causing the electrophoretic particles to move within the fluid to first and second states

Methodology Applied
Scientific EffectElectrophoresis: Electrophoresis

Implementation Method 2

adjust a reflection and refraction of light through the first and second layers and the fluid

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 3

when the particles are in the second state the device provides a high absorbance

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentEP2401651B1Multilayer light modulator
Publication Date: 2019.07.03 RAYTHEON CO
  • EP2401651B1 patent drawingFigure 1~3
  • EP2401651B1 patent drawingFigure 2A~2C

AI summary

A multilayer light modulator includes, a light modulating stack operable to transform an electrical control signal into a modulated optical signal. The light modulating stack comprises one or more optically- reflecting layers, optically transmitting layers, and optically variable layers. The optically variable layer comprises a plurality of electrophoretic particles supported in a fluid. The multilayer light modulator also includes a bias generator coupled to the optically variable layers. The bias generator is responsive to the electrical control signal, wherein the bias generator creates a bias that changes the reflectance of the light modulating stack by causing the electrophoretic particles to move within the fluid.