3m Innovative Properties Company

Minnesota Mining and Manufacturing Company

David P Erickson

Michele A Waldner

Orlin Bruce Knudson

William J Kelliher, Jr

Jia Hu

Hatim M Carim

Richard L Rylander

Chaodi Li

Michael J Rude

Bruce P Ekholm

Scott D Pearson

Jon A Kirschhoffer

Andrew P Bonifas

John M Kruse

Mitchell B Grunes

Chester Piotrowski

Peter M Eisenberg

Stephen J Willett

Robert A Sainati

Edward D Goff

Janet T Keller

Andrew Bonifas

Swagata R Banerjee

Edmund J Ring

James P McGee

Diane E Morel

Cheryl Lee Senger Elsbernd

Gene J Hickok

James P Mcgee

Some aspects of the present disclosure feature a sensing device comprising a magnetic bias layer, a resonator, a spacer, and a housing. The spacer includes an environmental change receptor. The thickness of the environmental change receptor rapidly increases in response to a change to an environment variable.

Magneto-mechanical resonator sensor with absorption material

Some aspects of the present disclosure feature a system for sensing a change in environment comprising a MMR sensor and a reader. The MMR sensor is configured to be disposed in the environment. The MMR sensor comprises a magnetic bias layer, a resonator, a spacer, and an environmental change receptor. The reader is configured to measure a frequency characteristic of the MMR sensor after the environmental variable changes and the change to the environmental variable is evaluated based on the frequency characteristic.

Systems and methods for magneto-mechanical resonator sensors

The invention provides one or more signal line structures that produce an electromagnetic field having a magnitude of at least an interrogation threshold of a radio frequency identification (RFID) tag for a substantial portion of an interrogation region. The signal lines may be made from copper and laid across a shelf in a storage area. The electromagnetic field may cause the tag to backscatter radio frequency (RF) signals to an RFID reader via the signal line.

Signal line structure for a radio-frequency identification system

Various systems and methods of handling items such as files are disclosed, including systems and methods for polling RFID-tagged items while they are stored in storage areas.

Radio frequency identification in document management

Various radio frequency identification (RFID) tags are described that dynamically vary their resonant frequency to reduce or eliminate the potential effects of electromagnetic 'tag-to-tag' coupling. An RFID tag, for example, includes a main antenna tuned to a first resonant frequency, and switching circuitry that dynamically changes the resonant frequency of the main antenna. The switching circuitry may selectively couple electrical elements, such as capacitive elements, inductive elements, or combinations thereof, to vary the resonant frequency of the RFID tag. The RFID tag may include a sensing circuit that determines when to selectively couple the electrical element to the main antenna to adjust the resonant frequency of the main antenna.

Variable frequency radio frequency identification (RFID) tags

A device for verifying a location of a radio-frequency identification (RFID) tag on an item. One embodiment of the invention provides a device for verifying the location of an RFID tag on an item including: an item holder; and an RF antenna attached to the item holder, where the item holder includes a readable volume where the RF antenna can read or write to an RFID tag, and where the item holder includes a non-readable volume where the RF antenna cannot read or write to an RFID tag. The present invention also relates to methods of verifying the location of a radio-frequency identification (RFID) tag on an item.

Device for verifying a location of a radio-frequency identification (RFID) tag on an item

A method and apparatus for the direct noninvasive prediction of hematocrit in mammalian blood using photoplethysmography techniques and data processing. The method and apparatus also include optional prediction of other analytes of interest: percent oxygen saturation of mammalian blood and methemoglobin of stored blood. The method and apparatus can be used for the immediate, periodic, or continuous noninvasive diagnosis or monitoring of hematocrit levels in mammalian patients without pain to the patient or exposure of the health care practitioner to the blood of the patient.

Method and apparatus for noninvasive prediction of hematocrit

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Stillwater, MN, United States of America

David P Erickson