The history of book anti-theft can be divided into three stages, namely mechanical anti-theft, electromagnetic anti-theft, and
RFID anti-theft. The theft prevention of medieval European books was simple and crude, directly locking the books with iron chains. In the 19th century, the invention of electronic article surveillance systems (EAS) made it possible to manage open shelves for books. In the 20th century,
RFID technology replaced electromagnetic anti-theft technology and became the mainstream book anti-theft technology in libraries
Method.
During the era of mechanical anti-theft, books were usually locked in cabinets or tied to desks with book chains, and keys were managed by dedicated personnel. Books are like prisoners, extremely unfree in circulation! At present, there are still a few iron chain libraries in the form of cultural relics preserved in the Hereford Cathedral Library in the UK, the Jutterfen Library in the Netherlands, and the Malatesta Library in Italy. Mechanical anti-theft reflects the lack of technology at that time, and there was a rigid iron chain between books and readers, which was very inconvenient to use.
EAS is currently a widely used electronic commodity security and anti-theft system
One, Electronic Article Surveillance (EAS) system includes electromagnetic anti-theft system, radio frequency anti-theft system, and acoustic magnetic anti-theft system. It mainly consists of three parts: detector, decoder, and electronic tag.
Electromagnetic anti-theft system uses electromagnetic waves as detection signals, mainly composed of anti-theft antennas, demagnetizers, magnetic strips, and magnetic strip detectors. As shown in the figure, the transmitting antenna of the left gate generates a specific electromagnetic field. When the magnetic stripe passes between the left and right gates, the electromagnetic field will excite and generate high-order harmonics. If the right gate detects high-order harmonics, it will sound an alarm. A magnetic stripe is usually a slender metal strip that can be discreetly inserted into the spine of a book. The electromagnetic anti-theft system can adopt two modes: separation of people and books and demagnetization carrying. Libraries generally adopt demagnetization carrying mode. The separation of people and books refers to the process where readers directly pass through the anti-theft system after borrowing books, and then take the books away from the side of the anti-theft door after leaving the house. Demagnetized carrying refers to the manual demagnetization of books by librarians through equipment when readers borrow books, and readers carrying non-magnetic books through anti-theft systems. The drawback of electromagnetic anti-theft is that the anti-theft system is prone to identifying self purchased books carried into the library by readers, causing false alarms. In addition, book thieves may use materials such as tin foil or iron boxes to wrap books, or use strong magnets to shield electromagnetic fields by placing books together, thereby rendering the anti-theft function of the anti-theft system ineffective.
With the development of
RFID technology, book anti-theft technology has entered a new stage.
RFID technology has better anti-theft capabilities and gradually replaces magnetic stripe anti-theft, becoming the mainstream technology and means of book anti-theft at present. The
RFID anti-theft system achieves non-contact recognition through alternating magnetic field or electromagnetic field spatial coupling, and generally works at two frequencies: high frequency (13.56MHz) and ultra-high frequency (860-960MHz). Compared with traditional EAS electromagnetic anti-theft systems,
RFID book anti-theft has advantages such as fast recognition speed, high recognition rate, and large amount of information. The main components of an
RFID anti-theft system include electronic tags, readers, and antennas. Electronic tags have built-in chips and antennas as data carriers for the system. The reader is a read-write device responsible for controlling the communication between the RF module and the tag, while the antenna serves as an intermediary for data transmission between the tag and the reader. The process of
RFID anti-theft system recognition is that when the electronic tag enters the magnetic field, it sends out the book information stored in the chip by the induced current. After the reader reads and decodes the information, it is sent to the anti-theft information system for relevant data processing.
Library security door
It is an important component of the library anti-theft system, which can achieve rapid detection of electronic tags within the antenna sensing range of the security door. The application scope of security doors is very wide. They can not only be used for anti-theft at the entrance and exit of libraries, but also for anti-theft in archives, brand clothing stores, and other scenarios.
