JP2007148755A - Id tag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily check the state of electric wave intensity of an ID tag. <P>SOLUTION: An ID tag 1 includes a light emitting diode 4. The light emitting diode 4 emits light according to a voltage level output from a rectifier circuit 5 which generates a power supply voltage by rectifying the power produced by electromagnetic induction of an electric wave output from a reader/writer. With this, it is possible to visually grasp the supply condition of the electric wave and electric wave intensity quantitatively, from the presence or non-presence of the light emission from the light emitting diode 4, and the degree of emitted light intensity. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a communication technology of a semiconductor integrated circuit device, and more particularly to a technology effective for grasping radio wave intensity in an RFID (Radio Frequency IDentification) tag.

  RFID is spreading as an automatic recognition technology capable of data communication by wireless communication. The RFID includes an ID tag that can store information and a reader / writer that reads and writes information from the ID tag. The ID tag includes, for example, a semiconductor integrated circuit device such as a non-contact IC chip and an antenna.

  This type of ID tag is provided with a regulator. This regulator reduces the voltage generated at the antenna terminal, which has become too high when data communication is performed in a region where the radio wave intensity is strong, to an arbitrary voltage level. Thereby, destruction of the semiconductor element of the semiconductor integrated circuit device is prevented.

  However, the present inventors have found that the ID tag as described above has the following problems.

  In ID tag wireless communication, in a region where the radio wave intensity is weak during data communication, the voltage generated at the antenna terminal becomes too low, and the semiconductor integrated circuit device does not operate. In this case, it is possible to grasp the radio wave intensity to some extent at the point where the ID tag stops operating.

  However, there is no means for quantitatively grasping the electric field strength applied to the ID tag, the radio wave state, the power supply state, etc. in a region where the radio wave intensity is high, that is, under a strong electric field, thereby causing a problem in wireless communication. There is a problem that analysis at the time of occurrence becomes difficult.

  The objective of this invention is providing the technique which can confirm the state of the electromagnetic wave intensity in an ID tag easily.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  The present invention is an ID tag that converts radio waves received from a reader / writer into power and returns information to the reader / writer, and when the radio waves received from the reader / writer are converted into power, A power detection light emitting unit that emits light according to the electric power is provided.

  Moreover, the outline | summary of the other invention of this application is shown briefly.

  In the present invention, the power detection light emitting unit is formed of a light emitting diode.

  In the present invention, the light-emitting diode is made of a surface mount component.

  Furthermore, in the present invention, the light emitting diode is connected to a semiconductor chip for controlling the ID tag by a bonding wire.

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

  (1) It is possible to quantitatively grasp the radio wave supply state and radio wave intensity visually by the presence or absence of light emission in the power detection light emitting unit and the intensity of light emission.

  (2) According to the above (1), it is easy to grasp the radio wave supply state and radio wave intensity in the ID tag, and the reliability of the ID tag can be improved.

  (3) Further, by using a light emitting diode as the power detection light emitting unit, a voltage limiter effect that makes the rectified voltage constant can be obtained, and a protective circuit such as a regulator can be eliminated from the ID tag.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

  FIG. 1 is a block diagram of an ID tag according to an embodiment of the present invention, and FIG. 2 is a plan view showing an outline of the ID tag of FIG.

  In the present embodiment, the ID tag 1 is used for RFID, which is one of automatic recognition technologies, for example. As shown in FIG. 1, the ID tag 1 includes an antenna 2, an RFID chip 3, and a light emitting diode (LED: Light Emitting Diode) 4.

  The antenna 2 transmits and receives analog signals in communication with the reader / writer. The RFID chip 3 includes a rectifier circuit 5, a clock circuit 6, a modulation circuit 7, a logic circuit 8, and a smoothing capacitor 9.

  The rectifier circuit 5 is connected to the antenna 2 via an antenna pad 3a and a ground (reference potential) pad 3b. The rectifier circuit 5 rectifies electric power by electromagnetic induction of radio waves output from a reader / writer that reads and writes information in the ID tag via the antenna 2 and outputs the rectified power as a power supply voltage VCC.

  The clock circuit 6 generates a clock signal and supplies it to the logic circuit 8. The modulation circuit 7 demodulates the analog signal received by the antenna 2 into a digital signal and outputs it to the logic circuit 8, and also modulates the digital signal output from the logic circuit 8 into an analog signal and reads it through the antenna 2. / Send to writer.

  The logic circuit 8 includes a memory made of a nonvolatile semiconductor memory such as an EEPROM (Electronically Erasable and Programmable Read Only Memory), for example, and controls operation in reading / writing information, and reads / writes information. The smoothing capacitor 9 smoothes the power supply voltage VCC generated by the rectifier circuit 5.

  The light emitting diode (power detection light emitting unit) 4 is connected between the voltage monitor pad 3c and the ground pad 3b of the RFID chip 3, and emits light according to the voltage level of the power supply voltage VCC output from the rectifier circuit 5. .

  The antenna 2, the RFID chip 3, and the light emitting diode 4 are laminated in, for example, paper or plastic, and formed in a card shape.

  FIG. 2 is a plan view showing a configuration example of the ID tag 1.

  The antenna 2 is made of a metal such as copper or aluminum, and is formed in a rectangular film shape as illustrated. A slit for optimizing the antenna gain is formed at an arbitrary position of the antenna 2. The antenna 2 transmits and receives analog signals in communication with the reader / writer.

  The RFID chip 3 is mounted on the antenna 2, and a ground pad 3 b formed on the back surface of the RFID chip 3 is connected to the main surface of the antenna 2. An antenna pad 3 a is formed on the main surface of the RFID chip 3, and the antenna pad 3 a is connected to the tip of the slit formed in the antenna 2 via a bonding wire 10.

  In the light emitting diode 4, the anode formed on the main surface of the light emitting diode 4 is connected to the voltage monitor pad 3 c through the bonding wire 11. Further, the cathode formed on the back surface of the light emitting diode 4 is directly connected to the main surface of the antenna 2.

  When data communication with the reader / writer is started by wireless communication, the rectifier circuit 5 of the ID tag 1 receives a radio wave from the reader / writer, and the voltage level power supply proportional to the radio wave intensity received by the antenna 2 A voltage VCC is generated.

  Since the power supply voltage VCC is applied to the voltage monitor pad 3c, if the conversion efficiency of the rectifier circuit 5 is known in advance, the supply of radio waves depends on whether or not the light emitting diode 4 emits light and the intensity of light emitted from the light emitting diode 4. The state and the radio wave intensity can be quantitatively grasped visually.

  Further, by providing the light emitting diode 4 to discharge the electric charge of the smoothing capacitor 9, a voltage limiter effect that makes the rectified voltage constant can be obtained. Thereby, a protection circuit such as a regulator is not necessary, and the RFID chip 3 can be further downsized.

  Thereby, according to the present embodiment, the radio wave intensity in the ID tag 1 can be confirmed by visual observation, so that it is easy to grasp the radio wave supply state and the radio wave intensity, and the reliability of the ID tag is improved. Can be improved.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  The present invention is suitable for a technique for improving the reliability of an ID tag used for RFID.

It is a block diagram of the ID tag by one embodiment of this invention. It is a top view which shows the ID tag outline | summary of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ID tag 2 Antenna 3 RFID chip 3a Antenna pad 3b Ground (reference potential) pad 3c Voltage monitor pad 4 Light emitting diode (power detection light emitting unit)
5 Rectifier circuit 6 Clock circuit 7 Modulation circuit 8 Logic circuit 9 Smoothing capacitors 10 and 11 Bonding wire VCC Power supply voltage

Claims (4)

An ID tag that converts radio waves received from a reader / writer into electric power and returns information to the reader / writer,
An ID tag, comprising: a power detection light emitting unit that emits light in accordance with electric power when radio waves received from the reader / writer are converted into electric power. The ID tag according to claim 1,
The ID tag, wherein the power detection light emitting unit is a light emitting diode. The ID tag according to claim 2,
The light emitting diode is formed of a surface mount component. In the ID tag according to claim 2 or 3,
The light emitting diode is
The ID tag is connected to a semiconductor chip for controlling the ID tag by a bonding wire.

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