Pixelated Optical Filter Subpixel Segmentation for Tunable Color

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Solution Overview

Problem

Conventional zero-order diffractive filters face challenges in achieving tunable and recognizable color effects that are easily identifiable by the human eye, requiring precise adjustments of grating period, depth, thickness, fill factor, and refractive indices, which can be complex to manufacture and maintain.

Innovation Solution

A pixelated optical filter with high-index refraction material positioned between low-index refraction matter, featuring a plurality of subpixels with different grating patterns that diffract specific zero-order wavelength spectra, allowing for tunable color effects upon rotation and tilting, and can be manufactured using embossing and replication processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional zero-order diffractive filters use precise adjustments of grating period, depth, thickness, fill factor, and refractive indices to achieve recognizable color effects, then the color effects become tunable and identifiable, but the manufacturing complexity increases

Engineering Contradiction:
Improvecolor effect recognitionVSAvoidmanufacturing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The filter is divided into multiple subpixels, each with different grating patterns (different periods, depths, or orientations). This segmentation allows the system to achieve complex color effects through simple combinations of basic grating units, reducing overall manufacturing complexity while maintaining color tunability and recognizability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions (subpixels) of the filter have locally optimized grating properties tailored to produce specific color effects. Each subpixel can have customized grating parameters (period, depth, fill factor) to achieve its designated function, allowing precise color control without requiring the entire structure to be complex

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If conventional zero-order diffractive filters use precise adjustments of multiple parameters to achieve tunable color effects, then the color effects become recognizable, but the ease of manufacture decreases

Engineering Contradiction:
Improvecolor effect tunabilityVSAvoidmanufacturing ease
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

By segmenting the filter into standardized subpixel units with discrete grating patterns, the system achieves color tunability through spatial arrangement of simple units rather than precise control of complex continuous parameters, significantly improving ease of manufacture

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention achieves color effect tunability by changing the spatial distribution and combination of subpixels with different grating parameters, rather than requiring precise adjustment of each parameter across the entire filter. This discrete parameter approach simplifies manufacturing

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 pixelated optical filter achieves recognizable and tunable color effects, suitable for security and authentication applications, with improved manufacturing efficiency and versatility in displaying combined characteristic color effects.

Implementation Method 1

high-index refraction material positioned between low-index-refraction matter... operative to act as a leaky waveguide for light incident on the pixelated optical filter

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

high-index refraction material... operative to act as a leaky waveguide for light incident on the pixelated optical filter

Methodology Applied
Scientific EffectWaveguide: Waveguide (optics)

Implementation Method 3

grated structure comprising a plurality of at least one grating pattern... operative to diffract incident light to at least one zero-order wavelength spectrum

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 4

grated structure comprises a plurality of at least one grating pattern that is planarly bounded. Each of the plurality of at least one grating pattern constitutes a subpixel

Methodology Applied
Scientific EffectDiffraction grating: Diffraction Grating

Data Source

PatentEP2447744B1Pixelated optical filter and method for the manufacturing thereof
Publication Date: 2021.03.31 CSEM CENTRE SUISSE D ELECTRONIQUE ET DE MICROTECHNIQUE SA
  • EP2447744B1 patent drawingFigure 1
  • EP2447744B1 patent drawingFigure 2
  • EP2447744B1 patent drawingFigure 3

AI summary

The present invention discloses a pixelated optical filter comprising high-index refraction material positioned between low-index-refraction matter. At least some of the high-index refraction material has a grated structure and lateral and vertical dimensions with respect to the low-index-refraction matter such that the high-index refraction material is operative to act as a leaky waveguide for light incident on the pixelated optical filter. The grated structure comprises a plurality of at least one grating pattern that is planarly bounded. Each of the plurality of at least one grating pattern constitutes a subpixel. A plurality of subpixels is operative to diffract incident light to at least one zero-order wavelength spectrum respective of the at least one grating pattern. Additional and alternative embodiments are disclosed and claimed.