INFORMATION ACCESS SYSTEM, INFORMATION STORAGE DEVICE AND READER/WRITER DEVICE

• US 20100026469A1
• Filed: 04/30/2009
• Published: 02/04/2010
• Est. Priority Date: 07/29/2008
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Yamada, Isamu, Shiotsu, Shinichi, Yamashita, Daisuke, Tanaka, Hideki, Inano, Satoshi
• Granted Patent: US 8,587,413 B2
• Time in Patent Office: Days
• US Class Current: 340/10.510
• CPC Class Codes: G06K 19/0705 the battery being connected to a power saving arrangement
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• 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: G06K 7/10059 transponder driven
• CPC Class Codes: G06K 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas

Abstract

An information access system includes a reader/writer device and an information storage device. In the information storage device, a receiver unit senses a carrier of an RF signal at a first frequency for detection, in a first time period occurring at time intervals, and receives an information request signal in response to detection of a carrier of an RF signal at the first frequency, and senses a carrier of an RF signal at a second frequency in response to reception of the information request signal. In the storage device, a control causes the receiver unit to sense a carrier of an RF signal at the first frequency for detection, in a second time period after a sleep time period which is shorter than the time interval, in response to non-detection by the receiver unit of a carrier of an RF signal at the first frequency in the first time period.

Claims

1. An information access system comprising:

a reader/writer device comprising;

a first memory,

a first timing generator for measuring time,

a first transmitter unit for transmitting an information request signal at a first frequency in a transmission time period,

a first receiver unit for receiving a response signal at a second frequency which is different from the first frequency, and

a first control for causing the first transmitter unit to suspend its transmission in a non-transmission time period; and

an information storage device comprising;

a second memory for storing an identification,

a second timing generator for measuring time,

a battery,

a second receiver unit for sensing a carrier of an RF signal at a first frequency for detection, in a first time period occurring at time intervals, and further receiving the information request signal in response to detection of a carrier of an RF signal at the first frequency, and for sensing a carrier of an RF signal at the second frequency in response to reception of the information request signal,

a second control for causing the second receiver unit to sense a carrier of an RF signal at the first frequency for detection, in a second time period after a sleep time period which is shorter than the time interval, in response to non-detection by the second receiver unit of a carrier of an RF signal at the first frequency in the first time period, and

a second transmitter unit for transmitting the response signal at the second frequency in response to non-detection by the second receiver unit of a carrier of an RF signal at the second frequency in the first time period.

2. An information access system comprising:

a reader/writer device comprising;

a first memory,

a first timing generator for measuring time,

a first transmitter unit for transmitting an information request signal at a first frequency in a transmission time period,

a first receiver unit for receiving a response signal at a second frequency which is different from the first frequency, and for sensing a carrier of an RF signal at the first frequency in a first time period within a non-transmission time period, and

a first control for causing the first transmitter unit to suspend its transmission in the non-transmission time period, and for continuing the non-transmission time period and causing the first receiver unit to sense a carrier of an RF signal at the first frequency in a second time period after an inactivation time period, in response to detection by the first receiver unit of a carrier of an RF signal at the first frequency in the first time period; and

an information storage device comprising;

a second memory for storing an identification,

a second timing generator for measuring time,

a battery,

a second receiver unit for sensing a carrier of an RF signal at a first frequency for detection, in a third time period occurring at time intervals, and further receiving the information request signal in response to detection of a carrier of an RF signal at the first frequency, and for sensing a carrier of an RF signal at the second frequency in a fourth time period in response to reception of the information request signal,

a second control for causing the second receiver unit to sense a carrier of an RF signal at the first frequency for detection, in a fifth time period after a first sleep time period which is shorter than the time interval, in response to non-detection by the second receiver unit of a carrier of an RF signal at the first frequency in the third time period, and for causing the second receiver unit to sense a carrier of an RF signal at the second frequency for detection, in a sixth time period after a second sleep time period which is shorter than the time interval, in response to detection by the second receiver unit of a carrier of an RF signal at the second frequency in the fourth time period, and

a second transmitter unit for transmitting the response signal at the second frequency in response to non-detection by the second receiver unit of a carrier of an RF signal at the second frequency.

3. An information storage device comprising:

a memory for storing an identification,

a timing generator for measuring time,

a battery,

a receiver unit for sensing a carrier of an RF signal at a first frequency for detection, in a first time period occurring at time intervals, and further receiving an information request signal in response to detection of a carrier of an RF signal at the first frequency, and for sensing a carrier of an RF signal at a second frequency which is different from the first frequency, in response to reception of the information request signal,

a control for causing the receiver unit to sense a carrier of an RF signal at the first frequency for detection, in a second time period after a sleep time period which is shorter than the time interval, in response to non-detection by the receiver unit of a carrier of an RF signal at the first frequency in the first time period, and

a transmitter unit for transmitting the response signal at the second frequency in response to non-detection by the receiver unit of a carrier of an RF signal at the second frequency.

4. An information storage device according to claim 3, wherein

in response to non-detection by the receiver unit an RF signal at the first frequency in the first time period, the control causes the receiver unit to repeat a combination of a sleep state in the sleep time period and subsequent carrier sensing of an RF signal at the first frequency in the second time period, up to a maximum number of times unless a carrier of an RF signal at the first frequency is detected.

5. An information storage device comprising:

a memory for storing an identification;

a timing generator for measuring time;

a battery;

a receiver unit for sensing a carrier of an RF signal at a first frequency for detection, in a first time period occurring at time intervals, and further receiving an information request signal in response to detection of a carrier of an RF signal at the first frequency, and for sensing a carrier of an RF signal at a second frequency which is different from the first frequency in a second time period, in response to reception of the information request signal;

a control for causing the receiver unit to sense a carrier of an RF signal at the first frequency for detection, in a third time period after a first sleep time period which is shorter than the time interval, in response to non-detection by the receiver unit of a carrier of an RF signal at the first frequency in the first time period, and for causing the receiver unit to sense a carrier of an RF signal at the second frequency for detection, in a fourth time period after a second sleep time period which is shorter than the time interval, in response to detection by the receiver unit of a carrier of an RF signal at the second frequency in the second time period; and

a transmitter unit for transmitting the response signal at the second frequency in response to non-detection by the receiver unit of a carrier of an RF signal at the second frequency.

6. The information storage device according to claim 5, wherein in response to non-detection by the receiver unit of a carrier of an RF signal at the first frequency in the first time period, the control causes the receiver unit to repeat a combination of a sleep state in the first sleep time period and subsequent carrier sensing of an RF signal at the first frequency in the third time period, up to a first number of times unless a carrier of an RF signal at the first frequency is detected.

7. The information storage device according to claim 5, wherein, in response to detection by the receiver unit of a carrier of an RF signal at the second frequency in the second time period, the control causes the receiver unit to repeat a combination of a sleep state in the second sleep time period and subsequent carrier sensing of an RF signal at the second frequency in the fourth time period, up to a second number of times as long as a carrier of an RF signal at the second frequency is detected.

8. The information storage device according to claim 6, wherein, in response to detection by the receiver unit of a carrier of an RF signal at the second frequency in the second time period, the control causes the receiver unit to repeat a combination of a sleep state in the second sleep time period and subsequent carrier sensing of an RF signal at the second frequency in the fourth time period, up to a second number of times as long as a carrier of an RF signal at the second frequency is detected.

9. A reader/writer device comprising:

a memory;

a timing generator for measuring time;

a transmitter unit for transmitting an information request signal at a first frequency in a transmission time period;

a receiver unit for receiving a response signal at a second frequency which is different from the first frequency, and sensing a carrier of an RF signal at the first frequency in a first time period within a non-transmission time period; and

a control for causing the transmitter unit to suspend its transmission in the non-transmission time period, and, in response to detection by the receiver unit of a carrier of an RF signal at the first frequency in the first time period, continuing the non-transmission time period and causing the receiver unit to sense a carrier of an RF signal at the first frequency for detection, in a second time period after an inactivation time period.

10. The reader/writer device according to claim 9, wherein in response to detection by the receiver unit of a carrier of an RF signal at the first frequency in the first time period, the control causes the receiver unit to repeat a combination of an inactivation state of operation in the inactivation time period and subsequent carrier sensing of an RF signal at the first frequency in the second time period, up to a maximum number of times as long as a carrier of an RF signal at the first frequency is detected.