Non-contact tamper sensing by electronic means

Patent · Fri Jan 01 00:00:00 EST 1993

OSTI ID:868891

Gritton, Dale G ^[1]

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1. Pleasanton, CA

A tamper-sensing system for an electronic tag 10 which is to be fixed to a surface 11 of an article 12, the tamper-sensing system comprising a capacitor having two non-contacting, capacitively-coupled elements 16, 19. Fixing of the body to the article will establish a precise location of the capacitor elements 16 and 19 relative to each other. When interrogated, the tag will generate a tamper-sensing signal having a value which is a function of the amount of capacity of the capacitor elements. The precise relative location of the capacitor elements cannot be duplicated if the tag is removed and affixed to a surrogate article having a fiducial capacitor element 19 fixed thereto. A very small displacement, in the order of 2-10 microns, of the capacitor elements relative to each other if the tag body is removed and fixed to a surrogate article will result in the tamper-sensing signal having a different, and detectable, value when the tag is interrogated.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
• DOE Contract Number: W-7405-ENG-48
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 5237307
• OSTI ID: 868891
• Country of Publication: United States
• Language: English

Related Subjects

non-contact
tamper
sensing
electronic
means
tamper-sensing
tag
10
fixed
surface
11
article
12
comprising
capacitor
non-contacting
capacitively-coupled
elements
16
19
fixing
establish
precise
location
relative
interrogated
generate
signal
value
function
amount
capacity
duplicated
removed
affixed
surrogate
fiducial
element
thereto
displacement
2-10
microns
result
detectable
electronic means
relative location
fixed thereto
/340/324/