Passive Optical Identification Tags for Long-Range Low-Cost Tracking
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Solution Overview
Problem
Current automated identification technologies, such as RFID and bar codes, face limitations in range and cost, with passive RFID tags having effective ranges of only a few feet and active RFID tags being expensive due to power supply limitations, while bar code scanning is restricted to short distances.
Innovation Solution
The development of a passive thin embossed plastic optical identification tag using micro retroreflective arrays, refractive and diffractive holographic light modification elements, and nano-structural arrays for encoding information, enabling identification at long distances with a solid-state laser-based transceiver unit, potentially up to a mile, and at a lower cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If passive RFID tags are used for automated identification, then cost is reduced compared to active RFID, but identification range is limited to only a few feet
Solution Approach 1:
The patent replaces electromagnetic field-based RFID communication with optical communication using laser illumination. The optical identification tag uses retroreflective elements to reflect laser light back to the transceiver, enabling long-range identification without requiring active electronics or power supplies, thus maintaining low cost while achieving extended range.
Solution Approach 2:
The patent changes the operating wavelength from radio frequency to optical wavelength. By using visible or near-infrared laser light instead of RF signals, the system achieves much longer propagation distances while keeping the tag passive and inexpensive, resolving the contradiction between range and cost.
2Length of stationary object
If active RFID tags are used to increase identification range, then range is improved, but cost increases significantly due to active circuitry and power supplies
Solution Approach 1:
The patent extracts and removes the active electronics, power supplies, and associated circuitry from the RFID tag. By eliminating these expensive components, the system achieves long-range identification capability through passive optical reflection rather than active transmission, resolving the cost issue while maintaining extended range.
Solution Approach 2:
The patent uses simple, inexpensive passive optical elements (retroreflective arrays, holographic elements) that can be manufactured at low cost, replacing expensive active RFID components. These passive elements have no limited lifespan from battery degradation, providing a cost-effective long-range solution.
3Ease of manufacture
If bar code scanning is used for identification, then cost is kept low, but scanning distance is limited to several feet or inches
Solution Approach 1:
The patent replaces contactless optical scanning with laser-based illumination and retroreflection. The structured light patterns created by laser illumination of the retroreflective tag elements enable precise encoding detection at long distances, extending scanning range far beyond traditional bar code capabilities while maintaining low cost.
Solution Approach 2:
The patent transitions from 2D bar code patterns to 3D structured light patterns in space. By using spatially encoded light patterns from multiple retroreflective elements illuminated by laser, the system achieves long-range identification with enhanced precision and extended detection distance.
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 solution provides reliable identification over greater distances than existing technologies, maintaining a low-cost advantage while ensuring robustness through redundancy and error correction, suitable for applications like vehicle identification, toll-road fee collection, and inventory tracking.
Implementation Method 1
The tag may comprise a retroreflective array of light encoding elements
Implementation Method 2
refractive and diffractive holographic light modification elements
Implementation Method 3
refractive and diffractive holographic light modification elements
Data Source
AI summary
Embodiments for electro-optical identification are disclosed.