WO2010002170A2

WO2010002170A2 - Selective radio frequency (rf) identification tag using photo signals and method of implementing the same

Info

Publication number: WO2010002170A2
Application number: PCT/KR2009/003535
Authority: WO
Inventors: Young-Sup Lee
Original assignee: Hantherm Co., Ltd.
Priority date: 2008-06-30
Filing date: 2009-06-30
Publication date: 2010-01-07
Also published as: WO2010002170A3

Abstract

Provided are a selective radio frequency (RF) tag which is identified through a photo signal and a method of implementing the RF tag. The circuit of the RF tag is activated in response to a photo signal which is a selection signal for selecting the RF tag among a plurality of tags. Accordingly, the RF tag allows individual identification over a wide range of identification.

Description

SELECTIVE RADIO FREQUENCY (RF) IDENTIFICATION TAG USING PHOTO SIGNALS AND METHOD OF IMPLEMENTING THE SAME

The present invention relates to a radio frequency (RF) tag, and more particularly, to an RF tag which is identified through a photo signal and a method of implementing the RF tag.

Radio frequency identification (RFID) is a technology that incorporates the use of electromagnetic or electro static coupling in the radio frequency portion of the electromagnetic spectrum to identify an object, animal or person. Recently, the use of RFID is gradually increasing since it has the advantage of neither requiring direct contact nor scanning in the visual band.

For example, RFID may be used in various automation industries, business of distribution, livestock management, access control, diligence and indolence management, physical distribution management, parking management, etc. Also, RFID may be applied to various fields, such as credit/debit cards, prepaid cards, traffic cards, access cards for parking, department cards, products to be transferred on conveyer belts, postal delivery systems, identification tables in which information about animals is recorded, etc.

However, the RFID has difficulties in identifying only a specific tag when a plurality of different tags exist together. Accordingly, there may occur errors such as identifying irrelevant tags or failing to read any tag.

Accordingly, the present invention provides a radio frequency (RF) tag which allows individual identification over a wide range of identification and a method of implementing the RF tag.

According to an exemplary aspect, there is provided a Radio Frequency (RF) tag whose circuit is activated in response to a photo signal which is a selection signal for selecting the RF tag among a plurality of tags. The RF tag includes a photo-responsive element to control signal transmission in response to the photo signal, an antenna connected to one end of the photo-responsive element, and a circuit part connected to the other end of the photo-responsive element. The circuit part includes a memory in which tag information is stored, and a controller to process the tag information stored in the memory according to a radio signal which is received/transmitted through the antenna.

According to another exemplary aspect, there is provided an Radio Frequency (RF) tag identifying method including irradiating focused light on an RF tag among a plurality of RF tags, receiving/transmitting a radio signal from/to the RF tag activated by the irradiated focused light, and reading tag information of the activated RF tag based to the received/transmitted radio signal.

As described above, according to the present invention, there are provided a radio frequency (RF) tag allowing individual identification over a wide range of identification and a method of implementing the RF tag. That is, due to the use of RF, the range of identification is widened and the use of a photo-responsive element allows individual identification which is an advantage of barcodes.

Furthermore, a specific RF tag may be selected and designated even when a plurality of RF tags are simultaneously exposed, by focusing light on only the RF tag, so that the specific RF tag can be activated without a user's manipulation.

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and together with the description serve to explain the principles of the invention.

FIG. 1 is a reference view for explaining a radio communication method according to an exemplary embodiment.

FIG. 2 is a block diagram illustrating an RF tag according to an exemplary embodiment.

FIG. 3 is a block diagram illustrating an RF tag according to another exemplary embodiment.

FIG. 4 is a block diagram illustrating an RF tag reader according to an exemplary embodiment.

FIG. 5 is a flowchart illustrating an RF tag identifying method according to an exemplary embodiment.

The invention is described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure is thorough, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity. Like reference numbers in the drawings denote like elements.

Referring to FIG. 1, a radio frequency (RF) system 1 includes an RF tag 10 and an RF tag reader 20.

The circuit of the RF tag 10 is activated in response to a photo signal which is a selection signal to select the corresponding RF tag 10 among a plurality of tags. In detail, the circuit of the RF tag 10 is activated only when focused light is sensed by a photo-responsive element 100a exposed to the outside. Accordingly, the RF tag 10 allows individual identification over a wide range of identification. That is, due to the use of RF, the range of identification is widened and the use of the photo-responsive element 100 allows individual identification which is an advantage of barcodes. Details for the RF tag 10 will be described later with reference to FIGS. 2 and 3.

Meanwhile, the RF tag reader 20 irradiates focused light to the RF tag 10 selectively through a transmitter 200, and reads RF tag information from the RF tag 10 activated by the photo-responsive element 100a which has received the focused light. Also, the RF tag reader 20 may transmit the read results to another device.

The RF tag reader 20, as illustrated in FIG. 1, is configured to substantially equalize the light-focusing direction of a photo signal to the radio-oriented direction of the RF tag 10. That is, the light-focusing direction of a photo signal irradiated by the transmitter 200 of the RF tag reader 20 is equal to a radio communication direction between the antenna 230 of the RF tag reader 20 and the antenna of the RF tag 10.

If the RF tag reader 20 irradiates focused light toward one RF tag 10 among a plurality of RF tags simultaneously exposed, only the RF tag 10 may be selected. This method is to activate only a specific RF tag without a user's manipulation. Details for the RF tag reader 20 will be described later with reference to FIG. 4.

FIGS. 2 and 3 are block diagrams illustrating RF tags according to various exemplary embodiments.

In FIGS. 2 and 3, photo-

responsive elements

100a and 100b each is exposed outside the RF tag 10, and is a photoelectric transformation device that uses focused light irradiated by the RF tag reader 20 (see FIG. 1). Here, the photo-

responsive elements

100a and 100b each may control signal transmission depending on the amount of received light.

FIG. 2 is a block diagram illustrating an RF tag 10a according to an exemplary embodiment.

Referring to FIG. 2, the RF tag 10a includes a photo-responsive element 100a, an antenna 110a and a circuit part 120a. The circuit part 120a includes a memory 122a and a controller 124a.

The antenna 110a, which receives/transmit radio signals from/to the outside, is a passive element which can transmit or receive electromagnetic wave signals according to the electromagnetic induction principle. Meanwhile, the memory 122a which stores data may be an EEPROM, a ROM, a RAM or a combination thereof. However the memory 122a is not limited to these.

The photo-responsive element 100a is positioned between the antenna 110a and the circuit part 120a, and responds to a photo signal which is a selection signal to select one of a plurality of tags. Here, the photo-responsive element 100a may be a photo diode, a photo transistor, CdS, a solar cell, etc. Particularly, if the photo-responsive element 100a is made of CdS, the photo-responsive element 100a is a photo-sensitive element whose resistance varies depending on the amount of received light, that is, the photo-responsive element 100a behaves nearly as an insulator in dark places and has conductivity in bright places. However, the photo-responsive element 100a may be any other elements or materials.

Meanwhile, the photo-responsive element 100a, when sensing a photo signal transmitted from an external device (for example, an RF tag reader), forms an electrical connection between the antenna 110a and circuit part 120a. For example, when the photo-responsive element 100a senses focused light, the photo-responsive element 100a becomes conductive to form an electrical connection between the antenna 110a and controller 124a. Thus, the photo-responsive element 100a receives radio signals from the RF tag reader 20 through the antenna 110a, and rectifies or multiplies RF power to use as a supply voltage. Also, the photo-responsive element 100a backscatter-modulates frequency signals received from the RF tag reader 20 and transmits tag information to the RF tag reader 20.

The controller 124 is activated by the photo-responsive element 100a, and processes tag information stored in the memory 122a according to the radio signals received/transmitted through the antenna 110a. In detail, the controller 124a reads data stored in the memory 122a according to the radio signals received through the antenna 110 and transmits a radio signal created based on the read data to the outside through the antenna 110a. The memory 122a and controller 124a may be integrated into an IC chip in the form of Chip-On-Board (COB).

Meanwhile, according to an additional aspect, the RF tag 10a may further include an optical focusing unit (not shown) to focus light on the photo-responsive element 100a. The optical focusing unit may be a lens or in the form of a funnel, but is not limited to these. In detail, if the optical focusing unit is a concave lens, by focusing a light source (for example, laser which is diffused light) to create convergence light, focusing of the laser may be enhanced. Likewise, in the case where the optical focusing unit is a convex lens, focusing of light may also be enhanced since the light source is focused while passing through the convex surface. If the optical focusing unit is in the form of a funnel, the optical focusing unit may be installed in a light receiver of a remote controller.

In addition, the RF tag 10a may further include an electromagnetic wave shielding film to shield the memory 122a and controller 124a from external electric waves. In this case, it is possible to make the RF tag 10a activated only by the operation of the photo-responsive element 100a by shielding the memory 122a and controller 124a. This is aimed at preventing the case where the RF tag 10a may be read in a short range by an antenna component installed in the circuit part 120a even when there is no antenna 110a. The electromagnetic wave shielding film may be made of a conductor or semiconductor and shield the IC chip by covering the IC chip.

FIG. 3 is a block diagram illustrating an RF tag 10b according to another exemplary embodiment.

Referring to FIG. 4, the RF tag 10b includes a photo-responsive element 100b, an antenna 110b and a circuit part 120b. The circuit part 120b includes a memory 122a and a controller 124b.

The antenna 110b, which receives/transmit radio signals from/to the outside, is a passive element which can transmit or receive electromagnetic wave signals according to the electromagnetic induction principle. Meanwhile, the memory 122b which stores data may be an EEPROM, a ROM, a RAM or a combination thereof. However the memory 122b is not limited to these.

The photo-responsive element 100b is exposed to the outside, and responds to a photo signal which is a selection signal to select one of a plurality of tags. Here, the photo-responsive element 100b may be a circuit including at least one photo-sensitive resistor and at least one switch, wherein the photo-sensitive resistor may be one of a photo diode, a photo transistor, CdS, a solar cell and the like, and the switch may be one of a MOS, a FET, a RF switch and the like that can be controlled by the photo-sensitive resistor. However, the photo-responsive element 100b is not limited to the above-mentioned examples.

When the controller 124b is electrically connected to the antenna 110b and receives radio signals from the antenna 110b, the controller 124b processes tag information stored in the memory 122b only when the switch is turned on in response to a photo signal from the photo-responsive element 100b. The switch is turned on when the controller 124a senses a change in voltage depending on the amount of received light.

For example, referring to FIG. 3, when the photo-responsive element 100b senses a photo signal, a voltage value read by the controller 124b becomes 0 V and the controller 124b senses this change in voltage, thus processing tag information stored in the memory 122b. In detail, when the photo-responsive element 100b senses a photo signal from the outside (that is, an RF tag reader), the controller 124b rectifies or multiplies RF power using a radio signal of the RF tag reader received through the antenna 110b and uses the result of the rectifying or multiplying as a supply voltage. Then, the controller 124b backscatter-modulates a frequency signal received from the RF tag reader and transmits tag information stored in the memory 122b to the RF tag reader.

Meanwhile, according to an additional aspect, the RF tag 10b may further include an optical focusing unit (not shown) to focus light on the photo-responsive element 100b. The optical focusing unit may be a lens or in the form of a funnel but is not limited. In detail, if the optical focusing unit is a concave lens, by focusing a light source (for example, laser light which is diffused light) to thus create convergence light, focusing of the laser can be enhanced. Likewise, in the case where the optical focusing unit is a convex lens, focusing of light may also be enhanced since the light source is focused while passing through the convex surface. If the optical focusing unit is in the form of a funnel, the optical focusing unit may be installed in a light receiver of a remote controller.

In addition, the RF tag 10a may further include an electromagnetic wave shielding film to shield the memory 122b and controller 124b from external electric waves. In this case, it is possible to make the RF tag 10b activated only by the operation of the photo-responsive element 100b by shielding the memory 122b and controller 124b. This is aimed at preventing the case where the RF tag 10b may be read in a short range by an antenna component installed in the circuit part 120b even when there is no antenna 110b. The electromagnetic wave shielding film may be made of a conductor or semiconductor and shield the IC chip by covering the IC chip.

In summary, in the embodiments of FIGS. 2 and 3, the photo-

responsive elements

100a and 100b are exposed to the outside, and the RF tags 10a and 10b are activated only when responding to a photo signal which is a selection signal to select one of a plurality of tags. However, it is also possible that other components in the RF tags 10a and 10b are activated according to the locations of the photo-

responsive elements

100a and 100b. As a result, the RF tags 10a and 10b each allows individual identification over a wide range of identification. That is, due to the use of RF, the range of identification is widened and the use of a photo-responsive element allows individual identification which is an advantage of barcodes. In addition, the RF tags 10a and 10b each may be an active- or passive-type. Preferably, the RF tags 10a and 10b may be passive tags.

Referring to FIG. 4, the RF tag reader 20 includes a transmitter 200, a controller 210, a tag reader 220 and an antenna 230.

The transmitter 200 irradiates focused light to select one of a plurality of RF tags. At this time, the transmitter 200 may be a laser diode but is not limited.

In detail, the light-focusing direction of the transmitter 200 is configured to be substantially equal to the radio-oriented direction of the tag reader 220 which will be described later. That is, since the transmitter 200 orientedly focuses light on one RF tag among a plurality of RF tags, a specific RF tag may be selected and designated even when the RF tags are simultaneously exposed, so that the specific RF tag is activated without a user's manipulation.

The tag reader 220 activates an RF tag by irradiating focused light on the RF tag and receives/transmits radio signals from/to the RF tag. Here, the radio-oriented direction of the tag reader 220 may be equal to the light-focusing direction of the transmitter 200. Meanwhile, the controller 210 reads information of the RF tag based on a radio signal received/transmitted through the tag reader 220 or transmits the information of the RF tag to an external device.

Referring to FIG. 5, focused light is irradiated on one RF tag among a plurality of RF tags (operation 100). At this time, a light-focusing direction may be configured to be equal to a radio-oriented direction. Accordingly, only one RF tag is selected and designated even when a plurality of RF tags are simultaneously exposed, so that the specific RF tag can be activated without a user's manipulation.

Successively, radio signals are received/transmitted from/to the RF tag activated by the focused light irradiated thereon (operation 110). Then, tag information of the activated RF tag is read based on the radio signals (operation 120). Then, the read tag information may be transmitted to an external device (operation 130).

In summary, in the RF tag according to this exemplary embodiment, due to the use of RF, the range of identification is widened and the use of a photo-responsive element allows individual identification which is an advantage of barcodes. Furthermore, one RF tag may be selected and designated even when a plurality of RF tags are simultaneously exposed, by focusing light on only the RF tag, so that the specific RF tag may be activated without a user's manipulation.

It will be apparent to those of ordinary skill in the art that various modifications can be made to the exemplary embodiments of the invention described above. However, as long as modifications fall within the scope of the appended claims and their equivalents, they should not be misconstrued as a departure from the scope of the invention itself.

As described above, the present invention can be applied to various RF tags and RF tag readers.

Claims

An Radio Frequency (RF) tag whose circuit is activated in response to a photo signal which is a selection signal for selecting the RF tag among a plurality of tags.
The RF tag of claim 1, comprising:

a photo-responsive element to control signal transmission in response to the photo signal;

an antenna connected to one end of the photo-responsive element; and

a circuit part connected to the other end of the photo-responsive element.
The RF tag of claim 2, wherein the circuit part comprises:

a memory in which tag information is stored; and

a controller to process the tag information stored in the memory according to a radio signal which is received/transmitted through the antenna.
The RF tag of claim 2, further comprising an electromagnetic wave shielding film to shield the circuit part from external electric waves.
The RF tag of claim 2, further comprising an optical focusing unit to focus light on the photo-responsive element.
The RF tag of claim 5, wherein the optical focusing unit is a lens or in the form of a funnel.
An radio frequency (RF) tag reader comprising:

a transmitter to irradiate focused light;

a tag reader unit to receive/transmit a radio signal from/to an RF tag; and

a controller to read tag information based on a radio signal received/transmitted from/to an RF tag activated by receiving the focused light.
The tag reader of claim 7, wherein the transmitter irradiates laser light.
The tag reader of claim 7, wherein a light-focusing direction of the transmitter is substantially equal to a radio-oriented direction of the tag reader unit.
An Radio Frequency (RF) tag identifying method comprising:

irradiating focused light on an RF tag among a plurality of RF tags;

receiving/transmitting a radio signal from/to the RF tag activated by the irradiated focused light; and

reading tag information of the activated RF tag based to the received/transmitted radio signal.