Retro-Reflective Disc Target With NIR Reflection Suppression

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Solution Overview

Problem

Traditional disc targets for optical tracking systems suffer from inaccuracies due to direct light reflections and border material reflections, particularly near-infrared (NIR) light reflections, which degrade tracking accuracy and resistance to contaminants.

Innovation Solution

A multi-layered retro-reflective marker design featuring a bare retro-reflective layer, a near-infrared (NIR) wavelength-specific anti-reflective coating, and an NIR absorbent border coating, which reduces direct reflections and suppresses stray light, maintaining high accuracy and resistance to contaminants.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional encapsulated retro-reflective tape is used to achieve wipeability, then resistance to contaminants is improved, but tracking accuracy deteriorates due to direct light reflections and border material reflections

Engineering Contradiction:

Improveresistance to contaminantsVSAvoidtracking accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The marker is divided into distinct functional layers: a retro-reflective layer with exposed beads for accuracy, a protective layer for wipeability, and a border layer for contamination resistance. Each layer performs a specific function, resolving the contradiction between accuracy and contaminant resistance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the marker have different properties: the center region has exposed retro-reflective beads for maximum tracking accuracy, while the border region has a protective coating for wipeability and contaminant resistance. This local differentiation allows each region to optimize its specific function.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If encapsulated retro-reflective tape is used, then wipeability is achieved, but direct light reflections from the top-encapsulating layer interfere with retro-reflected signals

Engineering Contradiction:

ImprovewipeabilityVSAvoidtracking accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The marker structure separates the retro-reflective function (exposed beads in center) from the protective function (coating on border), allowing the retro-reflective layer to provide accurate signals without interference from encapsulating layer reflections.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The encapsulating material is removed from the retro-reflective bead region, leaving only a thin protective coating on the border. This extraction eliminates the source of direct reflections that interfere with tracking accuracy while preserving wipeability where it is most needed.

Inventive Principle:

Principle #2Taking out (Extraction)

3Strength

If commonly used bordering material (plastic, anodized aluminum) is used, then structural integrity is maintained, but NIR light reflections add inaccuracies to the retro-reflected signal

Engineering Contradiction:

Improvestructural integrityVSAvoidtracking accuracy

Core Design Contradiction:

StrengthVSMeasurement precision

Solution Approach 1:

The border material's optical properties are modified by applying an NIR-absorbent coating, changing its reflectivity characteristics from high NIR reflection (which causes inaccuracies) to low NIR reflection, thereby eliminating the harmful effect while maintaining structural integrity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The border combines structural material (plastic or anodized aluminum) with an NIR-absorbent coating layer, creating a composite structure that provides both mechanical strength and optimized optical properties for accurate tracking.

Inventive Principle:

Principle #40Composite materials

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 multi-layered design significantly reduces inaccuracies, enhancing tracking accuracy up to three times compared to conventional markers while maintaining wipeability and resistance to contaminants.

Implementation Method 1

passive retro-reflective markers configured to reflect an optical signal to the tracking object in a retro-reflective manner (e.g., such that optical signals are reflected back towards a source of the optical signal with minimum scattering)

Methodology Applied

Scientific EffectRetro-reflection: Retroreflector

Implementation Method 2

a protective layer with a near-infrared (NIR) wavelength specific anti-reflective coating

Methodology Applied

Scientific EffectAnti-reflective coating: Anti-Reflective Coating

Implementation Method 3

a border with an NIR absorbent coating

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentUS12498509B2Retro-reflective disc target having exposed retro-reflective beads

Publication Date: 2025.12.16 NORTHERN DIGITAL

AI summary

A retro-reflective marker comprising a bare retro-reflective layer; a protective layer with a near-infrared (NIR) wavelength specific anti-reflective coating; and a border with an NIR absorbent coating.