Data medium for identifying objects, scanning device for interrogation of the data medium and process for controlling the data medium

• US 5,731,762 A
• Filed: 06/10/1996
• Issued: 03/24/1998
• Est. Priority Date: 12/10/1993
• Status: Expired due to Term

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG Osterreich (Siemens AG)
• Inventors: Gila, Janos, Asperger, Karl, Hraby, Gunther, Schiefer, Martin, Veith, Peter-Ernst
• Primary Examiner(s): Horabik, Michael
• Assistant Examiner(s): Beaulieu, Yonel
• Application Number:
  US08/664,993
• Time in Patent Office: 652 Days
• Field of Search: 340/825.54, 340/825.49, 340/568, 340/505, 340/572, 343/767, 343/768, 343/769
• US Class Current: 340/10.42
• CPC Class Codes: G01V 15/00 Tags attached to, or associated with, an object, in order to enable detection of the object record carriers for use with machines having a detectable tag or marker G06K19/00

Abstract

A data medium for identifying objects, in particular gas cylinders, includes a data source and an energy source. Each data medium contains at least one RF signal reflector having a characteristic frequency which can be controlled by the data source. The waveform of the characteristic frequency containing the individual identification of the data medium is in coded form. A scanning device for interrogation of the data medium and a process for controlling the data medium are also provided.

Claims

1. A data medium for identifying objects, comprising a data source, an energy source, and at least one RF signal reflector having a characteristic frequency, said data source periodically recurrently controlling said signal reflector with a period corresponding to a predetermined period of time, whereby the period of time is divided into a first interval and a second interval, and said data source further modulating the characteristic frequency of said signal reflector in the first interval for permitting an individual identification be interrogated by a scanning device, while the characteristic frequency of said signal reflector is not controlled in the second interval.

2. The data medium according to claim 1, wherein said at least one signal reflector is a slot antenna.

3. The data medium according to claim 2, wherein said slot antenna includes a plastic base and a metal layer having a slot formed therein.

4. The data medium according to claim 1, including an impedance to be controlled by said data source for controlling the characteristic frequency of said signal reflector.

5. The data medium according to claim 2, including an impedance to be controlled by said data source for controlling the characteristic frequency of said signal reflector, said slot antenna having two longitudinal borders, and said controllable impedance including two variable capacitance diodes being inserted between said two longitudinal borders and being connected in series in high frequency terms and in parallel in low frequency terms.

6. The data medium according to claim 1, including a plurality of signal reflectors being curved in divided circle form and joined together to form a circular ring.

7. The data medium according to claim 1, wherein the objects are products.

8. In combination, a data medium and a scanning device for interrogation of the data medium,

the data medium comprising:

a data source, an energy source, and at least one RF signal reflector with a characteristic frequency, said data source periodically recurrently controlling said signal reflector with a period corresponding to a predetermined period of time, whereby the period of time is divided into a first interval and a second interval, and said data source further modulating the characteristic frequency of said signal reflector in the first interval for permitting an individual identification to be interrogated by a scanning device, while the characteristic frequency of said signal reflector is not controlled in the second interval; and

the scanning device comprising an RF transmitting device, an RF receiving device and an evaluation circuit.

9. A process for controlling a data medium having a data source, an energy source, and at least one RF signal reflector antenna with a characteristic frequency to be controlled by the data source, which comprises:

periodically recurrently controlling the reflector antenna by the data source with a period corresponding to a predetermined period of time;

subdividing the period of time into at least a first and a second interval;

modulating the characteristic frequency of the reflector antenna by the data source in the first interval for permitting an individual identification to be interrogated by a scanning device; and

providing no control of the characteristic frequency of the reflector antenna in the second interval.

10. The process according to claim 9, which comprises setting a length of time for the second interval at a multiple of a length of time for the first interval.

11. The process according to claim 9, which comprises marking a beginning of the first interval by a synchronization signal and marking an end of the first interval by a check signal.

12. The process according to claim 9, which comprises storing an individual identification of the data medium as a digital code in the data source, and converting the code into an orthogonal pulse sequence with which the characteristic frequency of the signal reflector is modulated.

13. The process according to claim 9, which comprises controlling a plurality of data media and assigning each data medium a predetermined period of time different from the predetermined periods of time assigned to the respectively other data media, and time-shifting the periods of time in relation to one another.

14. The process according to claim 13, which comprises setting the predetermined periods of time in a group of data sources to be of different-length integral multiples of a predetermined time period, and time-shifting the periods of time in relation to one another.

15. The process according to claim 9, which comprises controlling a plurality of data media and assigning each data medium a predetermined period of time and setting different lengths for the predetermined periods of time with timing elements having limited accuracy.