Electronic article surveillance

Electronic article surveillance (EAS) is a type of system used to prevent shoplifting from retail stores, pilferage of books from libraries, or unwanted removal of properties from office buildings. EAS systems typically consist of two components: EAS antennas and EAS tags or labels. EAS tags are attached to merchandise; these tags can only be removed or deactivated by employees when the item is properly purchased or checked out. If merchandise bearing an active tag passes by an antenna installed at an entrance/exit, an alarm sounds alerting staff that unauthorized merchandise is leaving the store. Some stores also have antennas at entrances to restrooms to deter shoppers from taking unpaid-for merchandise into the restroom where they could remove the tags. EAS tags that could be attached to items in stores were invented by Arthur Minasy in 1964. He filed a patent for his "Method and Apparatus for Detecting the Unauthorized Movement of Articles" in 1965 with the patent being granted in 1970. There are several major types of electronic article surveillance systems: Electro-magnetic, also known as magneto-harmonic or Barkhausen effect Acousto-magnetic, also known as magnetostrictive Radio frequency (RFID, 8.2 MHz) Microwave Video surveillance systems (to some extent) Concealed EAS surveillance systems These new types of systems have caught on lately as there are no visible pedestals or hindrance in the store facade. These systems are installed below the floor and dropped from the ceiling and can then protect merchandise of retailers from being stolen. There are site conditions and other parameters which enable them to be successfully installed but often it has now been noted that malls insist on concealed system as a mandate to improve the shopping experience. These tags are made of a strip of amorphous metal (metglas) which has a very low magnetic saturation value. Except for permanent tags, this strip is also lined with a strip of ferromagnetic material with a moderate coercive field (magnetic "hardness").