ONE-TIME SENSOR DEVICE

• US 20110038395A1
• Filed: 08/10/2010
• Published: 02/17/2011
• Est. Priority Date: 08/12/2009
• Status: Active Grant

• Current Assignee: TSI Technolocies, LLC
• Original Assignee: TSI Technolocies, LLC
• Inventors: Clothier, Brian L., Sorkine, Evgeni
• Granted Patent: US 8,485,723 B2
• Time in Patent Office: Days
• US Class Current: 374/163
• CPC Class Codes: C22C 45/04 with nickel or cobalt as the major constituent
• CPC Class Codes: G01K 3/04 in respect of time
• CPC Class Codes: G01K 5/48 the material being a solid
• CPC Class Codes: G01K 7/36 using magnetic elements, e.g. magnets, coils magnetic elements per se H01F
• CPC Class Codes: G01R 33/02 Measuring direction or magnitude of magnetic fields or magnetic flux G01R33/20 takes precedence
• CPC Class Codes: H01F 1/0308 with magnetic shape memory [MSM], i.e. with lattice transformations driven by a magnetic field, e.g. Heusler alloys
• CPC Class Codes: H01F 1/15316 based on Co H01F1/15325 takes precedence
• CPC Class Codes: H01F 1/15333 containing nanocrystallites, e.g. obtained by annealing
• CPC Class Codes: H01F 1/15391 Elongated structures, e.g. wires

Abstract

One-time, single-use sensor elements (22, 46) are provided for detecting the occurrence of predetermined conditions such as temperature and elapsed time-temperature. The sensor elements (22, 46) preferably comprise elongated, glass-coated, metal alloy, amorphous or nanocrystalline microwires (30, 48), which can be placed in a position to detect the predetermined condition of interest. An alternating magnetic field detector (28) may be used to continuously or periodically interrogate the sensor elements (22, 46) to determine if the predetermined condition has occurred. In one aspect of the invention, the microwires (30, 48) experience a change in configuration upon the occurrence of the predetermined condition, and have correspondingly different induced remagnetization responses. In another embodiment, a static microwire is provided having an initial bi-stable single domain; when a predetermined time-temperature condition is experienced, multiple domains are established in the microwire, and this can be detected by the detector (28).

Claims

1. A one-time sensor assembly operable for sensing a predetermined condition, said sensor assembly comprising:

a sensor unit including;

an elongated, resilient sensor element;

a support for said sensor element;

structure releasably holding said sensor element in a first configuration on said support,

said sensor element operable to assume a second configuration different than said first configuration when said condition occurs; and

a detector separate from said sensor element and including a transmitter unit operable to transmit interrogating electromagnetic radiation to said sensor element,

said sensor element having a first response to said radiation when the sensor element is in said first configuration, and a second response different from said first response when the sensor element is in said second configuration,

said detector operable to detect the difference between said first and second responses.

2. The sensor assembly of claim 1, said sensor element comprising an amorphous or nanocrystalline sensor microwire having a positive magneto striction property, said first and second responses being respective remagnetization responses.

3. The sensor assembly of claim 2, said transmitter unit operable to create an alternating magnetic field of sufficient magnitude to magnetically couple with said sensor microwire in order to interrogate the sensor microwire and induce sensor microwire remagnetization responses, said detector further including a remagnetization sensor operable to sense the magnitude of said induced remagnetization responses.

4. The sensor assembly of claim 2, said first remagnetization response being a voltage amplitude of substantially zero, said second remagnetization response being a voltage amplitude substantially greater than zero.

5. The sensor assembly of claim 2, said sensor microwire being glass-coated.

6. The sensor assembly of claim 2, including a coating of shape memory material on said sensor element.

7. The sensor assembly of claim 1, said structure comprising adhesive releasably securing said sensor element to said support.

8. The sensor assembly of claim 1, said condition being a predetermined temperature experienced by said sensor element.

9. A method of detecting the occurrence of a predetermined condition, comprising the steps of:

placing a sensor unit in a position to sense said predetermined condition, said sensor unit including;

an elongated, resilient sensor element;

a support for said sensor element;

structure releasably holding said sensor element in a first configuration on said support,

said sensor element operable to assume a second configuration different than said first configuration when said condition occurs; and

interrogating said sensor element by transmitting interrogating electromagnetic radiation to said sensor element,

said sensor element having a first response to said radiation when the sensor element is in said first configuration, and a second response different from said first response when the sensor element is in said second configuration,

detecting said second response as an indication of occurrence of said predetermined condition.

10. The method of claim 9, including the steps of creating an alternating magnetic field of sufficient magnitude to magnetically couple with said sensor microwire in order to interrogate the sensor microwire and induce sensor microwire remagnetization responses, and detecting said induced remagnetization responses.

11. A one-time sensor element operable to sense a predetermined time-temperature condition, said sensor element comprising an elongated, amorphous or nanocrystalline metal alloy sensor microwire having a positive magnetostriction property, and a bi-stable single magnetic domain aligned along the length of the microwire which can exist at any given time in one of two stable magnetic states, said sensor microwire operable to lose its bi-stable single magnetic domain and have a plurality of magnetic domains oriented generally circumferentially along the length of the sensor microwire, when the sensor microwire experiences said predetermined time-temperature condition.

12. The sensor element of claim 11, said sensor microwire metal alloy containing chromium and having a glass coating.

13. A method of detecting a predetermined time-temperature condition, comprising the steps of:

placing a sensor element in a position to sense said predetermined time-temperature condition, said sensor element comprising an elongated, amorphous or nanocrystalline metal alloy sensor microwire having a positive magnetostriction property, and a bi-stable single magnetic domain aligned along the length of the microwire which can exist at any given time in one of two stable magnetic states, said sensor microwire operable to lose its bi-stable single magnetic domain and have a plurality of magnetic domains oriented generally circumferentially along the length of the sensor microwire, when the sensor microwire experiences said predetermined time-temperature condition; and

interrogating said sensor element by creating an alternating magnetic field of sufficient magnitude to magnetically couple with said sensor element and induce a response from the sensor element,

said sensor element exhibiting a remagnetization response prior to experiencing said predetermined time-temperature condition, and failing to exhibit a remagnetization response after experiencing said predetermined time-temperature condition.

14. The sensor element of claim 13, said sensor microwire metal alloy containing chromium and having a glass coating.

15. The sensor of claim 13, including the step of placing a reference microwire in proximity to said sensor element, said reference microwire having a positive magnetostriction property and operable to maintain a bi-stable single magnetic domain aligned along the length of the microwire which can exist at any given time in one of two stable magnetic states both prior to and after said sensor element experiences said pre-determined time-temperature condition.