Laser-Activated RFID Tag for Selective Long-Range Reading
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Solution Overview
Problem
Current RFID technologies face challenges in long-range selective reading due to poor signal-to-noise ratios and directional issues, making it difficult to target specific items in environments with multiple co-located RFID tags, especially when combined with the limitations of barcode reading methods like laser scanning and 2D imaging.
Innovation Solution
A portable data terminal (PDT) equipped with a laser and RFID reader unit that uses a processor IC chip to control the operation of both imaging and RFID functions, including a photosensitive device in RFID tags that requires specific laser light activation to enable precise reading, allowing for directional antenna alignment and isolation from other RFID signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional RFID reading is used in crowded environments, then RFID tags can be read, but the signal-to-noise ratio deteriorates and selective reading becomes difficult
Solution Approach 1:
The patent introduces laser light as an intermediary mediator between the RFID reader and the photosensitive device in RFID tags. The laser beam selectively activates only the target tag's photosensitive device, creating a controlled signal pathway that filters out interference from other tags in the crowded environment, thereby improving signal-to-noise ratio without increasing device complexity
Solution Approach 2:
The patent applies local quality by making the RFID tag's photosensitive device responsive only to specific laser light characteristics (wavelength, intensity, duration). This creates a localized activation zone where only the targeted tag responds to the laser signal, enabling selective reading in crowded environments while maintaining simple RFID reader architecture
2Length of stationary object
If laser scanning is used for long range barcode reading, then reading distance increases, but signal-to-noise ratio deteriorates
Solution Approach 1:
The patent changes the parameters of light interaction by using laser light with specific wavelength and intensity characteristics that match the photosensitive device's response characteristics. This parameter matching enables long-range reading while maintaining high signal-to-noise ratio, as the photosensitive device is selectively activated only by the matching laser parameters, not by ambient light or other interferers
3Measurement precision
If RFID tags are made directional for selective reading, then targeting accuracy improves, but compatibility with conventional readers deteriorates
Solution Approach 1:
The patent achieves universality by designing the RFID tag with dual functionality: the photosensitive device responds to both conventional RFID electromagnetic fields and selective laser activation. This multi-functionality allows the tag to be read by conventional RFID readers while enabling selective targeting when laser-activated, maintaining backward compatibility while adding new selective reading capability
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 reliable, long-range, selective reading of RFID tags even in crowded environments by using laser-activated RFID tags, improving data capture and reducing interference from other RFID signals, thereby enhancing data density and reading accuracy.
Implementation Method 1
a photosensitive device in RFID tags that requires specific laser light activation
Data Source
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AI summary
A data transfer system includes a radio frequency identification (RFID) reader having a radio frequency transmitter and receiver and a laser. The data transfer system also includes a RFID tag on a container which has a first photosensitive device coupled to an electronic circuit in the tag which is in a first state when light from the laser is not striking the photosensitive device and in a second state when light from the laser is striking the photosensitive device such that the RFID tag transmits a signal only when a light beam from the laser is striking the photosensitive device. The tag may be passive, semi-passive (battery assisted passivc-BAP), or active. If the tag is BAP then the laser light causes the tag to wake up so that it can respond to the RF signal from a RFID reader. The radio frequency transmitter provides power to the RFID tag sufficient to transmit a signal to the receiver which can be decoded by the RFID reader when the RFID reader is 40 feet or more away from the RFID tag.