Reflected Light Identification Device for Long-Range Passive Tagging
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Solution Overview
Problem
RFID systems face challenges in reading multiple tags simultaneously due to interference and have limited range, with passive tags restricted to 20 feet and active tags being expensive and maintenance-intensive.
Innovation Solution
The use of reflected light identification (RLID) systems that employ light sources and reflective film structures to encode and transmit data over long distances with minimal interference, utilizing passive and active RLID structures that can operate without power sources or with energy harvesting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If passive RFID tags are used for identification, then no power source is required, but the transmission range is limited to 20 feet
Solution Approach 1:
The patent replaces radio frequency electromagnetic waves with optical waves (light) as the transmission medium. This substitution enables passive tags to reflect light signals over much longer distances compared to traditional RFID radio wave transmission, thereby extending the transmission range without requiring active power sources.
Solution Approach 2:
The patent changes the transmission parameter from radio frequency to optical frequency. By using visible light or other optical wavelengths instead of radio waves, the system achieves extended transmission range while maintaining passive operation, as optical signals can be reflected effectively by passive structures over longer distances.
2Length of stationary object
If active RFID tags are used to extend transmission range to 100 yards, then transmission range is improved, but cost and maintenance requirements increase prohibitively
Solution Approach 1:
The patent replaces active electronic transmitters with passive optical reflectors. By using mirrors or reflective surfaces to bounce light signals back to receivers, the system achieves long-range transmission without requiring batteries, power management circuits, or active electronic components, thereby eliminating maintenance needs and reducing costs.
Solution Approach 2:
The patent employs inexpensive passive reflective elements such as mirrors or printed reflective patterns that can be manufactured at low cost. These elements have no moving parts or consumable components, making them essentially maintenance-free and economically viable for widespread deployment.
3Productivity
If multiple RFID tags are read simultaneously, then identification efficiency is improved, but signal interference makes it difficult to read multiple tags
Solution Approach 1:
The patent segments the optical spectrum into multiple wavelength channels. By assigning different wavelengths to different tags or using wavelength division multiplexing, multiple tags can be identified simultaneously without interference, as each wavelength channel operates independently.
Solution Approach 2:
The patent employs time-division multiplexing where tags reflect light signals in periodic sequences or at different time intervals. This allows the receiver to distinguish between multiple tags by detecting their unique temporal patterns, enabling simultaneous identification without signal interference.
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
Enables efficient and interference-free data transmission over long distances, allowing for the identification of objects and information without the need for power sources or frequent maintenance, enhancing the range and cost-effectiveness of identification systems.
Implementation Method 1
reflected light identification (RLID) systems that employ light sources and reflective film structures to encode and transmit data
Data Source
AI summary
A reflected light identification (RLID) system uses light to communicate stored information across long distances with minimal interference. The RLID system may include a light source that directs an incident light signal to an RLID structure, which then transmits an encoded light signal to a sensor. The RLID system may include a passive RLID structure (i.e., a structure that does not include power source) such as an RLID reflection surface that includes layered reflective films that reflect the incident light signal back in multiple reflections that serially encodes data. The RLID system may also include an active RLID structure (i.e., a structure that includes power source) that uses energy harvesting to extract and accumulate power from an incident light signal, and then uses the harvested energy to transmit a return signal.