Sensor tag and manufacturing method for sensor tag

• US 10,234,334 B2
• Filed: 08/14/2015
• Issued: 03/19/2019
• Est. Priority Date: 02/22/2013
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Ito, Yoshihiro
• Primary Examiner(s): Jagan, Mirellys
• Application Number:
  US14/826,228
• Publication Number:
  US 20150346039A1
• Time in Patent Office: 1,313 Days
• Field of Search: 374117, 374184
• CPC Class Codes: G01K 1/024 for remote indication
• CPC Class Codes: G01K 7/32 using change of resonant frequency of a crystal
• CPC Class Codes: G06K 19/0717 the sensor being capable of sensing environmental conditions such as temperature history or pressure
• CPC Class Codes: H01Q 1/085 Flexible aerials; Whip aerials with a resilient base
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H04Q 2209/47 using RFID associated with sensors
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom
• CPC Class Codes: Y10T 29/49005 Acoustic transducer

Abstract

A sensor tag (10) includes an antenna (102) and connection conductors (103) formed on a surface of a flexible substrate (101). A sensing element (110) is mounted on land conductors (131) of the connection conductors (103). The sensing element (110) is composed of a crystal vibrator (111) and an RFIC (112). The crystal vibrator (111) receives an excitation signal from the outside and generates a resonance signal of a resonant frequency corresponding to the sensed temperature. Equivalent circuit constant information including at least an equivalent inductance (Lxs) or an equivalent capacitance (Cxs) of the crystal vibrator (111) are stored in the RFIC (112).

Claims

1. A sensor tag comprising:

a resonator that generates a resonance signal corresponding to a sensed physical quantity;

an antenna that radiates the resonance signal;

a connection conductor that connects the antenna and the resonator,

wherein the sensor tag is formed based on at least an equivalent inductance or an equivalent capacitance of the resonator; and

a storage unit that stores equivalent circuit constant information including at least the equivalent inductance or the equivalent capacitance.

2. The sensor tag according to claim 1,

wherein the storage unit is an RFIC configured to perform transmission control by transmitting the equivalent circuit constant information from the antenna.

3. The sensor tag according to claim 1, further comprising:

a base member that integrates the resonator, the antenna and the connection conductor with each other, the storage unit being an information recording mark attached to the base member, wherein the base member is a flexible substrate.

4. The sensor tag according to claim 1,

wherein the resonator is an element having a resonant frequency of the resonance signal changed with a sensed temperature.

5. The sensor tag according to claim 1,

wherein the resonator is a crystal vibrator.

6. The sensor tag according to claim 5,

wherein the resonator is an element having a resonant frequency of the resonance signal changed with a sensed temperature.

7. The sensor tag according to claim 1,

wherein the antenna is formed in a shape based on at least the equivalent inductance or the equivalent capacitance.

8. The sensor tag according to claim 7,

wherein the resonator is a crystal vibrator.

9. The sensor tag according to claim 7,

wherein the resonator is an element having a resonant frequency of the resonance signal changed with a sensed temperature.

10. The sensor tag according to claim 1,

wherein the connection conductor is formed in a shape based on at least the equivalent inductance or the equivalent capacitance.

11. The sensor tag according to claim 10, wherein the resonator is a crystal vibrator.

12. The sensor tag according to claim 10,

wherein the resonator is an element having a resonant frequency of the resonance signal changed with a sensed temperature.

13. The sensor tag according to claim 1,

wherein the resonator is connected to the connection conductor at a position based on at least the equivalent inductance or the equivalent capacitance.

14. The sensor tag according to claim 13,

wherein the resonator is a crystal vibrator.

15. The sensor tag according to claim 13,

wherein the resonator is an element having a resonant frequency of the resonance signal changed with a sensed temperature.

16. A manufacturing method for a sensor tag including a resonator that generates a resonance signal corresponding to a sensed physical quantity, an antenna that radiates the resonance signal and a connection conductor that connects the antenna and the resonator, the manufacturing method comprising:

a step of preparing a plurality of types of antennas having different inductances;

a step of measuring at least an equivalent inductance or an equivalent capacitance of the resonator;

a step of storing, in a storage unit, equivalent circuit constant information including at least the equivalent inductance or the equivalent capacitance; and

a step of selecting the antenna on the basis of at least the equivalent inductance or the equivalent capacitance.

17. A manufacturing method for a sensor tag including a resonator that generates a resonance signal corresponding to a sensed physical quantity, an antenna that radiates the resonance signal and a connection conductor that connects the antenna and the resonator, the manufacturing method comprising:

a step of measuring at least an equivalent inductance or an equivalent capacitance of the resonator;

a step of storing, in a storage unit, equivalent circuit constant information including at least the equivalent inductance or the equivalent capacitance; and

a step of changing a shape of the antenna on the basis of at least the equivalent inductance or the equivalent capacitance.