Hierarchical Optical Code for Distance-Based Data Encoding

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Solution Overview

Problem

Current barcode technologies, including QR codes, face limitations in encoding capacity and efficiency due to the need for visible boundaries and the inability to differentiate information at varying distances, leading to reduced data density and increased complexity in design.

Innovation Solution

A machine-readable optical code system utilizing a hierarchy of optical element sets with parent and child elements, where the same optical element can represent different information based on distance, allowing for increased encoding efficiency and simpler design by using a retroreflective substrate and infrared-absorbing materials to create a code visible only in the infrared spectrum.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If traditional 2D barcodes like QR codes are used, then data can be encoded in two dimensions, but the encoding capacity is limited by the need for visible boundaries and uniform bit sizes

Engineering Contradiction:
Improvedata encoding capacityVSAvoidcode design complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The code is segmented into multiple hierarchical levels with parent optical elements containing child optical elements. Each level serves different decoding distances, allowing the system to encode more data without increasing overall code complexity. The segmentation enables progressive disclosure of information based on viewing distance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Child optical elements are nested within parent optical elements, creating a multi-scale hierarchical structure. This nesting allows the same physical space to encode information at multiple resolution levels, effectively increasing encoding capacity without proportionally increasing code area or design complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Quantity of substance

If the size of optical elements is reduced to encode more data, then data density increases, but the decoding distance and reliability decrease

Engineering Contradiction:
Improvedata densityVSAvoiddecoding reliability at distance
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The system dynamically adapts the effective code resolution based on decoding distance. At greater distances, only parent optical elements are decoded providing reliable information. At closer distances, child optical elements become resolvable, increasing data density. This dynamic approach maintains reliability across varying distances while maximizing overall data capacity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent adds a temporal/distance dimension to the encoding system by creating multiple resolution levels. Instead of a single static resolution, the code provides different effective resolutions based on the decoding distance, allowing small optical elements to be reliably decoded when appropriate distance criteria are met.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If error correction level is increased to improve reliability, then decoding accuracy improves, but storage capacity decreases

Engineering Contradiction:
Improvedecoding accuracyVSAvoidstorage capacity
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

Error correction is segmented and applied at multiple hierarchical levels rather than uniformly across the entire code. Each parent-child relationship can have its own error correction parameters, allowing optimized allocation of correction capacity that preserves overall storage capacity while maintaining reliability.

Inventive Principle:
Principle #1Segmentation

4Measurement precision

If finder patterns and alignment markers are added to improve decoding accuracy, then orientation and bounds detection improve, but the available space for data encoding decreases

Engineering Contradiction:
Improveorientation detection accuracyVSAvoiddata encoding space
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

Optical elements serve multiple functions simultaneously - they encode data bits, provide hierarchical structure for distance-based decoding, and can function as alignment references through their nested relationships. This multi-functionality reduces the need for separate dedicated finder and alignment patterns, preserving more space for actual data encoding.

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

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 approach enables more information to be encoded in a smaller space, reduces the number of required finder elements, and allows for different information to be read at varying distances, enhancing data density and simplifying code design while maintaining accuracy.

Implementation Method 1

a retroreflective sheet and an optical code layer over the retroreflective sheet. The optical code layer includes a hierarchy of optical elements that absorb, scatter or otherwise inhibit retroreflection of the retroreflective sheet beneath the optical code layer

Methodology Applied
Scientific EffectRetroreflection: Retroreflector

Implementation Method 2

The optical code layer includes a hierarchy of optical elements that absorb, scatter or otherwise inhibit retroreflection of the retroreflective sheet beneath the optical code layer

Methodology Applied
Scientific EffectInfrared absorption: Absorption (EM radiation)

Data Source

PatentEP3520030B1Hierarchichal optical element sets for machine-read articles
Publication Date: 2023.05.24 3M INNOVATIVE PROPERTIES CO
  • EP3520030B1 patent drawingFigure 1
  • EP3520030B1 patent drawingFigure 2A~2B
  • EP3520030B1 patent drawingFigure 3~4A

AI summary

In some examples, an article includes a substrate, the substrate including a physical surface; a hierarchy of parent and child optical element sets embodied on the physical surface, wherein a first encoded value represented by the parent optical element set is based at least in part on a visual appearance of a particular optical element in the child optical element set, and a second encoded value represented by the particular optical element is based at least in part on the visual appearance, the first and second encoded values being different, and the second encoded value not being decodable from a distance greater than a threshold distance, the first encoded value being decodable from the distance greater than the threshold distance.