APPARATUS AND OPERATIVE METHOD FOR DETECTION AND READING OF TRANSPONDERS IN A CONTROLLED PASSAGE

• US 20020089429A1
• Filed: 11/27/1998
• Published: 07/11/2002
• Est. Priority Date: 06/30/1998
• Status: Active Grant

• Current Assignee: Manneschi Alessandro
• Original Assignee: Manneschi Alessandro
• Inventors: ALESSANDRO, MANNESCHI
• Granted Patent: US 6,452,481 B1
• Time in Patent Office: Days
• US Class Current: 340/870.11
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G07C 9/28 the pass enabling tracking or indicating presence

Abstract

The invention consists of an apparatus and an operative method with which a transponder is detected and read in a controlled passageway. The detection and reading apparatus is programmed to control its transmitter coil (Tx) so as to repeatedly emit a detecting electromagnetic field only for a brief interval of the transmission signal period, of a sufficient duration to allow the transponder to emit its presence signal. When the detection and reading apparatus receive the transponder'"'"'s first presence signal, the transmission coil (Tx) is instructed to emit an electromagnetic field of longer duration, sufficient to activate the transponder so that it emits its own complete coded signal so that it can be read and decoded.

In the following periods the transmitting coil (Tx) is instructed repetitively to emit an electromagnetic field that remains of brief duration as long as the transponder remains in the controlled passage. When detection of the transponder presence signal terminates, the detection and reading apparatus resets itself and returns to the control of the emission of electromagnetic fields of brief duration.

Claims

1. A detection and reading apparatus for transponders crossing a controlled passage, equipped with a group including the transmitting coil (Tx) and a group including the receiving coil (Rx), with the coils (Tx) and (Rx) to be installed in a position facing each other on the transit path or in a position that wraps around the passage to be controlled, characterized by at least one programmed Logic Control Group (2), and by the fact that said Group (2) on the one side, through appropriate electronic circuits, is connected to the receiving coil (Rx), on the other side is equipped with terminals (3) for its connections to external equipment, on one more side it is equipped with command plugs of which at least one (C1) is connected to the group including the transmission coil (Tx) to control the emission and reception of electromagnetic fields respectively for brief time intervals (presence revealing intervals) and for longer time intervals (reading intervals).

2. A method to control transponder detection-reading apparatus, with the help of the apparatus in claim 1. so as to detect and read transponders in transit in the controlled passage, characterized by a succession of phases through which:

the group including the transmitting coil (Tx) is commanded repeatedly so that it emits each time a detection electromagnetic field only for a brief interval of the period of the transmission signal (presence detection interval) of a sufficient duration to make the transponder emit a presence signal;

the group including the transmitting coil (Tx), following the reception by the receiving coil (Rx) of the first transponder presence signal in the controlled passage is commanded to emit an electromagnetic field for a sufficiently long interval (reading interval) capable of determining in the transponder in transit the emission of its own complete coded signal to allow its decoding and reading;

the group including the transmitting coil (Tx), following the reception in the receiving coil (Rx) of the complete coded signal emitted by the transponder in transit, is commanded repeatedly to emit an electromagnetic field that remains each time of brief duration (presence revealing interval) until the identified transponder remains in the controlled passage, with the aim of causing in the transponder in transit the sole emission of the transponder presence signal;

The Logic Control Group (2), which commands the duration of the emission of the electromagnetic field produced by the transmitting coil (Tx) of the transponder detection-reading apparatus, resets itself when the receiving coil (Rx) of the transponder detection-reading apparatus ceases to receive the transponder presence signals inside the controlled passage, for a programmed time interval.

3. The method, as claimed in claim 2, characterized by the fact that the group including the transmitting coil (Tx) of the transponder detection-reading apparatus is commanded so that it emits a detection electromagnetic field that is sufficiently intense only for a brief interval of time (presence revealing interval) but which is sufficient for the transponder in transit in the controlled passage, in whatever position it is oriented, to emit a transponder presence signal.

4. The method, as claimed in claim 2, characterized by the fact that the group including the transmitting coil (Tx) of the transponder detection-reading apparatus is commanded so that the transmitting coil (Tx), in the absence of a correct reading of the coded signal emitted by the transponder transiting in the controlled passage, repeats the emission of the electromagnetic field for a longer interval (reading interval) sufficient to provoke again the emission of the entire coded signal by the transponder in transit at most for n consecutive times, with n a whole and programmable number.

5. The method, as claimed in claim 2, characterized by the fact that the group including the transmitting coil (Tx) of the transponder detection-reading apparatus is commanded so that at the cessation of the reception of the transponder presence signal by the receiving coil (Rx), the Logic Control Groups 2 resets itself and commands it to emit detection electromagnetic fields of brief duration while awaiting the receipt of the first presence signal of the next transponder in transit.

6. The method, as claimed in claim 2, characterized by the fact that the partialisation system of the electromagnetic energy transmitted is made in such a way as to reveal first the presence of the transponder in transit and afterwards to prolong momentarily the duration of the emission for the time required to read it.

7. The method, as claimed in claim 2, characterized by the fact that the partialisation is obtained through levels of emitted electromagnetic field that are always different from zero and with modulated amplitudes.