Information processing device

• US 20060220863A1
• Filed: 03/06/2006
• Published: 10/05/2006
• Est. Priority Date: 03/16/2005
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Koyama, Jun
• Granted Patent: US 7,786,863 B2
• Time in Patent Office: Days
• US Class Current: 340/572.100
• CPC Class Codes: G08B 13/2402 Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting mechanical aspects of the tags, e.g. related to locking E05B73/0017; RFID readers G06K7/00; RFID tags G06K19/00; access control systems G07C9/00; anti-theft control in point of sale systems G07G3/003; security seals G09F3/03

Abstract

An information processing device of the invention has an antenna circuit, and a reader/writer device provided with a received signal generating circuit, a microcomputer, a transmitted signal generating circuit, a level detecting circuit, and a D/A converter. The received signal generating circuit is connected to the microcomputer and the antenna circuit, the transmitted signal generating circuit is connected to the microcomputer and the antenna circuit, the D/A converter is connected to the microcomputer and the antenna circuit, the level detecting circuit is connected to the microcomputer and the antenna circuit, and the antenna circuit has an antenna, a resonant capacitor, and a variable capacitor.

Claims

1. An information processing device comprising:

an antenna circuit; and

a reader/writer device including a received signal generating circuit, a microcomputer, a transmitted signal generating circuit, a level detecting circuit, and a D/A converter,

wherein the received signal generating circuit is connected to the microcomputer and the antenna circuit;

the transmitted signal generating circuit is connected to the microcomputer and the antenna circuit;

the D/A converter is connected to the microcomputer and the antenna circuit;

the level detecting circuit is connected to the microcomputer and the antenna circuit; and

the antenna circuit includes an antenna, a resonant capacitor, and a variable capacitor.

2. The information processing device according to claim 1, wherein the level detecting circuit comprises a diode, a capacitor, and an A/D converter.

3. The information processing device according to claim 1, wherein the level detecting circuit comprises a diode, a capacitor, an A/D converter, and choke coil.

4. The information processing device according to claim 1, wherein the variable capacitor comprises a variable capacitance diode, a coupling capacitor, and a voltage supply resistor.

5. The information processing device according to claim 1, wherein the antenna is any one of a dipole antenna, a patch antenna, a loop antenna, and a Yagi antenna.

6. An information processing device comprising:

an antenna circuit; and

a reader/writer device including a received signal generating circuit, a transmitted signal generating circuit, a level detecting circuit, a first D/A converter, a second D/A converter, a microcomputer, and a matching circuit,

wherein the received signal generating circuit is connected to the microcomputer and the antenna circuit;

the transmitted signal generating circuit is connected to the microcomputer and the antenna circuit;

the first D/A converter is connected to the microcomputer and the antenna circuit;

the second D/A converter is connected to the microcomputer and the matching circuit;

the level detecting circuit is connected to the microcomputer and the antenna circuit;

the antenna circuit includes an antenna, a resonant capacitor, and a first variable capacitor; and

the matching circuit includes a second variable capacitor.

7. The information processing device according to claim 6, wherein the level detecting circuit comprises a diode, a capacitor, and an A/D converter.

8. The information processing device according to claim 6, wherein the level detecting circuit comprises a diode, a capacitor, an A/D converter, and choke coil.

9. The information processing device according to claim 6, wherein at least one of the first variable capacitor and the second variable capacitor comprises a variable capacitance diode, a coupling capacitor, and a voltage supply resistor.

10. The information processing device according to claim 6, wherein the antenna is any one of a dipole antenna, a patch antenna, a loop antenna, and a Yagi antenna.

11. An information processing device comprising:

an antenna circuit including an antenna, a resonant capacitor, and a variable capacitor;

a received signal generating circuit that demodulates a voltage signal received by the antenna circuit and outputs the demodulated voltage signal to a microcomputer;

a transmitted signal generating circuit that modulates a voltage signal outputted from the microcomputer and transmits the modulated voltage signal to the antenna circuit;

a D/A converter for outputting a voltage signal for changing capacitance of the variable capacitor; and

a level detecting circuit that detects an output value of the antenna circuit when the modulated voltage signal and the voltage signal for changing capacitance of the variable capacitor from the D/A converter are inputted and that outputs the output value to the microcomputer.

12. The information processing device according to claim 11, wherein the level detecting circuit comprises a diode, a capacitor, and an A/D converter.

13. The information processing device according to claim 11, wherein the level detecting circuit comprises a diode, a capacitor, an A/D converter, and choke coil.

14. The information processing device according to claim 11, wherein the level detecting circuit regularly detects the output value.

15. The information processing device according to claim 11, wherein the variable capacitor comprises a variable capacitance diode, a coupling capacitor, and a voltage supply resistor.

16. The information processing device according to claim 11, wherein the antenna is any one of a dipole antenna, a patch antenna, a loop antenna, and a Yagi antenna.

17. An information processing device comprising:

an antenna circuit including an antenna, a resonant capacitor, and a first variable capacitor;

a received signal generating circuit that demodulates a voltage signal received by the antenna circuit and outputs the demodulated voltage signal to a microcomputer;

a transmitted signal generating circuit that modulates a voltage signal outputted from the microcomputer and transmits the modulated voltage signal to the antenna circuit;

a matching circuit including a second variable capacitor;

a first D/A converter for outputting a voltage signal for changing capacitance of the first variable capacitor;

a second D/A converter for outputting a voltage signal for changing capacitance of the second variable capacitor; and

a level detecting circuit that detects an output value of the antenna circuit when the modulated voltage signal and the voltage signal for changing capacitance of the first variable capacitor from the first D/A converter are inputted and that outputs the output value to the microcomputer.

18. The information processing device according to claim 17, wherein the level detecting circuit comprises a diode, a capacitor, and an A/D converter.

19. The information processing device according to claim 17, wherein the level detecting circuit comprises a diode, a capacitor, an A/D converter, and choke coil.

20. The information processing device according to claim 17, wherein the level detecting circuit regularly detects the output value.

21. The information processing device according to claim 17, wherein at least one of the first variable capacitor and the second variable capacitor comprises a variable capacitance diode, a coupling capacitor, and a voltage supply resistor.

22. The information processing device according to claim 17, wherein the antenna is any one of a dipole antenna, a patch antenna, a loop antenna, and a Yagi antenna.

23. A method for calibrating a resonant frequency of an information processing device,

said information processing device comprising:

an antenna circuit including a variable capacitor;

a transmitted signal generating circuit connected to a microcomputer and the antenna circuit;

a D/A converter connected to the microcomputer and the variable capacitor; and

a level detecting circuit connected to the microcomputer and the antenna circuit,

said method comprising the steps of;

outputting first signal from the antenna circuit in accordance with a signal outputted from the transmitted signal generating circuit to the antenna circuit;

changing a signal outputted from the antenna circuit to second signal by changing an outputted voltage from the D/A converter to the variable capacitor;

setting an output voltage of a signal outputted from the antenna circuit by outputting signals to the transmitted signal generating circuit and the D/A converter from the microcomputer by inputting voltage signals of the first signal and the second signal outputted from the antenna circuit to the microcomputer via the level detecting circuit.

24. The method for calibrating a resonant frequency of an information processing device according to claim 23, wherein the level detecting circuit comprises a diode, a capacitor, and an A/D converter.

25. The method for calibrating a resonant frequency of an information processing device according to claim 23, wherein the level detecting circuit comprises a diode, a capacitor, an A/D converter, and choke coil.

26. The method for calibrating a resonant frequency of an information processing device according to claim 23, wherein the variable capacitor comprises a variable capacitance diode, a coupling capacitor, and a voltage supply resistor.

27. The method for calibrating a resonant frequency of an information processing device according to claim 23, wherein the antenna is any one of a dipole antenna, a patch antenna, a loop antenna, and a Yagi antenna.

28. The method for calibrating a resonant frequency of an information processing device according to claim 23, wherein the microcomputer sets a signal outputted to one of the transmitted signal generating circuit, the first D/A converter and the second D/A converter so as to maximize an output of a signal from the antenna circuit.

29. A method for calibrating a resonant frequency of an information processing device,

said information processing device comprising:

an antenna circuit including a first variable capacitor;

a transmitted signal generating circuit connected to a microcomputer and the antenna circuit;

a matching circuit including a second variable capacitor;

a first D/A converter connected to the microcomputer and the first variable capacitor; and

a second D/A converter connected to the microcomputer and the second variable capacitor; and

a level detecting circuit connected to the microcomputer and the antenna circuit,

said method comprising the steps of;

outputting first signal from the antenna circuit in accordance with a signal outputted from the transmitted signal generating circuit to the antenna circuit;

changing a signal outputted from the antenna circuit to second signal by changing an outputted voltage from the first D/A converter to the first variable capacitor;

setting an output voltage of a signal outputted from the antenna circuit by outputting a signal to the transmitted signal generating circuit and the first D/A converter from the microcomputer by inputting voltage signals of the first signal and the second signal outputted from the antenna circuit to the microcomputer via the level detecting circuit;

outputting third signal from the antenna circuit in accordance with a signal outputted from the transmitted signal generating circuit to the antenna circuit;

changing a signal outputted from the antenna circuit to fourth signal by changing an outputted voltage from the second D/A converter to the second variable capacitor;

setting an output voltage of a signal outputted from the antenna circuit by outputting signals to the transmitted signal generating circuit and the second D/A converter from the microcomputer by inputting voltage signals of the third signal and the fourth signal outputted from the antenna circuit to the microcomputer via the level detecting circuit.

30. The method for calibrating a resonant frequency of an information processing device according to claim 29, wherein the level detecting circuit comprises a diode, a capacitor, and an A/D converter.

31. The method for calibrating a resonant frequency of an information processing device according to claim 29, wherein the level detecting circuit comprises a diode, a capacitor, an A/D converter, and choke coil.

32. The method for calibrating a resonant frequency of an information processing device according to claim 29, wherein at least one of the first variable capacitor and the second variable capacitor comprises a variable capacitance diode, a coupling capacitor, and a voltage supply resistor.

33. The method for calibrating a resonant frequency of an information processing device according to claim 29, wherein the antenna is any one of a dipole antenna, a patch antenna, a loop antenna, and a Yagi antenna.

34. The method for calibrating a resonant frequency of an information processing device according to claim 29, wherein the microcomputer sets a signal outputted to one of the transmitted signal generating circuit, the first D/A converter and the second D/A converter so as to maximize an output of a signal from the antenna circuit.

35. A method for calibrating a resonant frequency of an information processing device,

said information processing device comprising:

an antenna circuit including a first variable capacitor;

a transmitted signal generating circuit connected to a microcomputer and the antenna circuit;

a matching circuit including a second variable capacitor;

a first D/A converter connected to the microcomputer and the first variable capacitor; and

a second D/A converter connected to the microcomputer and the second variable capacitor; and

a level detecting circuit connected to the microcomputer and the antenna circuit,

said method comprising the steps of;

outputting first signal from the antenna circuit in accordance with a signal outputted from the transmitted signal generating circuit to the antenna circuit;

changing a signal outputted from the antenna circuit to second signal by changing an outputted voltage from the second D/A converter to the second variable capacitor;

setting an output voltage of a signal outputted from the antenna circuit by outputting a signal to the transmitted signal generating circuit and the second D/A converter from the microcomputer by inputting voltage signals of the first signal and the second signal outputted from the antenna circuit to the microcomputer via the level detecting circuit;

outputting third signal from the antenna circuit in accordance with a signal outputted from the transmitted signal generating circuit to the antenna circuit;

changing a signal outputted from the antenna circuit to fourth signal by changing an outputted voltage from the first D/A converter to the first variable capacitor;

setting an output voltage of a signal outputted from the antenna circuit by outputting signals to the transmitted signal generating circuit and the first D/A converter from the microcomputer by inputting voltage signals of the third signal and the fourth signal outputted from the antenna circuit to the microcomputer via the level detecting circuit.

36. The method for calibrating a resonant frequency of an information processing device according to claim 35, wherein the level detecting circuit comprises a diode, a capacitor, and an A/D converter.

37. The method for calibrating a resonant frequency of an information processing device according to claim 35, wherein the level detecting circuit comprises a diode, a capacitor, an A/D converter, and choke coil.

38. The method for calibrating a resonant frequency of an information processing device according to claim 35, wherein at least one of the first variable capacitor and the second variable capacitor comprises a variable capacitance diode, a coupling capacitor, and a voltage supply resistor.

39. The method for calibrating a resonant frequency of an information processing device according to claim 35, wherein the antenna is any one of a dipole antenna, a patch antenna, a loop antenna, and a Yagi antenna.

40. The method for calibrating a resonant frequency of an information processing device according to claim 35, wherein the microcomputer sets a signal outputted to one of the transmitted signal generating circuit, the first D/A converter and the second D/A converter so as to maximize an output of a signal from the antenna circuit.