Abstract:
The present disclosure generally describes radio frequency (RF) particles and an RF powder-containing base including a plurality of such RF particles. The RF particles may include an antenna element and an integrated circuit element coupled together by at least one interconnection. The base may be formed from sheet-like subjects, such as various kinds of cards, bills, and documents. Methods of forming the RF powder-containing base are also generally disclosed.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This patent application is a continuation of U.S. patent application Ser. No. 12/153,662, filed May 22, 2008, now U.S. Pat. No. 8,154,456, which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a radio frequency (RF) particles, a radio frequency powder-containing base and in particular, to RF powder-containing base which can read information or the like via radio waves. 
     BACKGROUND 
     Currently, it is considered that integrated circuit (IC) tags are products indicating the beginning of the ubiquitous age. Labels, Suica cards, FeRAM cards, or the like have been developed previously as RF-ID (micro radio identification). Many people expect that an IC tag market will certainly grow larger in the future. However, the market has not grown enough to be expected. The reason is that there are also problems such as cost, security, and privacy other than technologies, which must be solved socially. 
     In addition, the RF-ID technology is considered to apply to identification of documents which have proprietary nature such as bills or securities. Forgery of bills and the like have been problems, and embedding the IC tags into the bills or the like can be devised as a method for solving those problems. However, the above-described method has not been achieved yet due to a high cost or a large size of the IC tags. 
     The cost of the IC tag can be reduced by reducing the size of the IC tag chip. It is because the number of IC tag chips obtained from a single wafer can be increased if the size of the IC tag chips is reduced. An IC tag chip of 0.4 millimeters square has been developed so far. This IC tag chip can read memory data of 128-bit via a 2.45 GHz microwave (refer to, for example, Non-patent Document 1). 
     Meanwhile, the RF-ID technology applicable to identification of bills, credit cards, or the like using components other than the IC tag is also devised. As an example thereof, a plurality of resonators which resonate to a plurality of radio frequencies are made to be contained in a substrate composed of paper or plastic in Patent Document 1. The resonator is a passive individual resonator, and resonates when a plurality of resonators are radiated by electromagnetic waves with radio frequency, and thus an arrangement of the plurality of resonators is grasped by detecting the resonance, allowing the substrate to be identified. 
     Patent Document 1: Japanese Unexamined Patent Publication (Kokai) No. 10-171951. 
     Non-patent Document 1: “Micro Radio IC Tag Chip ‘μ-Chip’” by Mitsuo Usami in Applied Physics, Vol. 73, No. 9, 2004, p.1179-p.1183. 
     SUMMARY 
     Technologies described herein generally include a radio frequency particle. The radio frequency particle may include an integrated circuit overlying and in direct contact with a substrate, an insulating layer overlying and in direct contact with the integrated circuit such that the integrated circuit is positioned between the substrate and the insulating layer, an antenna element overlying and in direct contact with the insulating layer and at least one interconnection connecting the integrated circuit with the antenna element. 
     Technologies described herein generally include a radio frequency powder-containing base. The radio frequency base may include a plurality of radio frequency powder particles dispersed therein. Each of the radio frequency powder particles may include an integrated circuit overlying a substrate, an insulating layer overlying the integrated circuit, at least one antenna element disposed in the insulating layer and having an exposed surface and at least one interconnection extending from the integrated circuit to the antenna element. 
     Technologies described herein generally include methods of forming a base including a plurality of radio frequency powder particles. Such a method may include forming a first adhesive-containing solution containing first radio frequency powder particles responsive to electromagnetic waves having a first frequency, forming a second adhesive-containing solution containing second radio frequency powder particles responsive to electromagnetic waves having a second frequency different from the first frequency and applying the first and second adhesive-containing solutions to the base. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a sectional perspective view showing an embodiment of an RF powder-containing base according to the present disclosure; 
         FIG. 2  is a three dimensional view showing a sectional main part of a single RF powder particle contained in the RF powder-containing base according to the present embodiment; 
         FIG. 3  is a block diagram showing a configuration example of an integrated circuit contained in the RF powder particle of the RF powder-containing base according to the present embodiment; 
         FIG. 4  is a device configuration view illustrating an actual usage and an action of the RF powder-containing base according to the present embodiment; 
         FIG. 5  is a schematic view showing a signal exchange between a reader/writer and the RF powder-containing base; and 
         FIG. 6  is a view showing a transmission/reception relation of a radio-frequency electromagnetic wave with the reader/writer in an existence position of a single RF powder particle. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, embodiments (examples) according to the present disclosure will be explained based on accompanying drawings. 
       FIG. 1  is a sectional perspective view showing an RF powder-containing base according to an embodiment of the present disclosure.  FIG. 1  is an enlarged view showing that three kinds of RF powder particles  11 ,  12 , and  13  are contained in a base  10  made of paper as an example. Herein, a bill is used as an example of the base  10 . The RF powder particles  11 ,  12 , and  13  have sensitivity to the electromagnetic waves with different frequencies, respectively. Although the RF powder particles  11 ,  12 , and  13  are shown in  FIG. 1  while slightly changing sizes thereof, it is shown to easily understand that the RF powder particles  11 ,  12 , and  13  have sensitivity to the electromagnetic waves with different frequencies, respectively, and actually, the sizes 
     Actually, each of the above-described RF powder particles  11 ,  12 , and  13  is collectively treated in a use form of a powdery substance due to a large number of or a large quantity of RF powder particles, and configures the RF powder. Although the RF powder particles  11 ,  12 , and  13  are shown as  13  pieces in total in  FIG. 1 , the number of RF powder particles is not limited thereto. If the use form of the RF powder of the powdery substance is taken into consideration, the RF powder particles  11 ,  12 , and  13  dispersively spread over the base  10  with a sheet-like shape in practice. As described above, the base  10  which contains a large number of RF powders thereinside or a surface thereof will be referred to as “RF powder-containing base  10 .” 
     Additionally, the above-described “RF powder” means a powder, in which each of a large quantity of particles composing the powder (powdery substance) has an electrical circuit element for transmitting/receiving signals (information) with an external reader/writer device via radio waves (radio-frequency electromagnetic waves), and a normal use form is a collective form. 
       FIG. 2  is a sectional view showing a single RF powder particle ( 11 ). In  FIG. 2 , a thickness of the RF powder particle  11  is exaggeratedly shown. The RF powder particle  11  has a three-dimensional shape, in which with respect to a plurality of rectangular planes in outer front sides thereof, a size of the rectangular plane is not less than 0.05 millimeters square and not more than 0.30 millimeters square, and more particularly 0.15 millimeters square. In the RF powder particle  11  according to the present embodiment, a side L in the front shown in  FIG. 2  is 0.15 millimeters (150 micrometers). 
     The RF powder particle  11  has an integrated circuit (IC)  15  provided with a memory function, such as FeRAM, formed on a substrate  14 , such as silicon or the like, an insulating layer  16  with a thickness of approximately 30 micrometers formed on the integrated circuit  15 , and an antenna element  17  responsive to an electromagnetic wave with a specific frequency (for example, 2.45 GHz) formed on the insulating layer  16 . As an example of electrical circuit elements, transistors  18  and  19  which configure the integrated circuit  15 , interconnections  20  connected to the transistors  18  and  19 , and interconnections  21  for connecting the antenna element  17  and the integrated circuit  15  are shown in  FIG. 2 . The interconnections  21  are embedded in the insulator  16 . 
       FIG. 3  shows one example of a circuit configuration of the integrated circuit  15  provided in the RF powder particle  11 . The integrated circuit  15  is provided with a rectifier circuit  22 , a voltage suppressor  23 , an initialization circuit  24 , a clock circuit  25 , a control register  26 , a decoder  27 , and a memory  28 , for example. These circuit elements have following functions, respectively. 
     The rectifier circuit  22  has a function for rectifying radio-frequency electromagnetic waves incoming from the outside into a DC power supply voltage. For example, the 2.45 GHz electromagnetic wave which is introduced via the antenna  17  and an antenna terminal  29  is converted into a voltage for operating internal analog circuits and digital circuits by the rectifier circuit  22 . When the RF powder particles  11  approach a reader/writer  32  (refer to  FIG. 5 ) and the rectifier circuit  22  generates the excessive voltage in response to excessive electromagnetic wave energy from the reader/writer  32 , the voltage suppressor  23  suppresses the voltage and prevents semiconductor devices in the integrated circuit  15  from being damaged. The initialization circuit  24  controls start and end of the circuit operation and the clock circuit  25  demodulates a clock waveform. The memory  28  is, for example, an FeRAM in which identification numbers are stored. Contents in the Memory  28  are selected by the control register  26  and the decoder  27  to be transmitted to the reader/writer  32 . 
     While the RF powder particles  12  and  13  have substantially the same structures as that of the above-described RF powder particle  11 , resonance circuit systems including the antenna elements  17  respectively owned by the RF powder particles  11 ,  12 , and  13  are designed to have sensitivities to the electromagnetic waves with different frequencies. For example, the RF powder particle  11  is provided with the resonance circuit system which has sensitivity to the 2.45 GHz electromagnetic wave, the RF powder particle  12  is provided with the resonance circuit system which has sensitivity to a 2.0 GHz electromagnetic wave, and the RF powder particle  13  is provided with the resonance circuit system which has sensitivity to a 1.9 GHz electromagnetic wave. 
     Next, with reference to  FIGS. 4 through 6 , actual usages and actions of the RF powder-containing base (base  10 ) according to the embodiment of the present disclosure will be explained. 
     As illustrated in  FIG. 1 , the sheet-like base  10  such as a bill contains a considerable number of RF powder particles ( 11 ,  12 , and  13 ). A thickness of the base  10  is exaggeratedly and enlargedly shown in  FIG. 4 . When it is made to be contained in the base  10 , aqueous solutions (ink, paint, or the like) filled with an adhesive fixative containing the RF powder is made to soak into the base  10  with a dropper or the like. Thus, the RF powder is attached on a surface of the base  10  or is made to soak into the inside of the base  10 . Alternatively, the RF powder may be mixed into the base  10  when manufacturing the base  10 . For example, if the base  10  is paper, the RF powder is mixed thereinto when making paper. 
     The base  10  is scanned by the reader/writer  32  connected to a computer  31 . The computer  31  reads information included in each of the plurality of RF powder particles via the reader/writer  32 . The computer  31  is provided with a display  31   a , a main unit  31   b , a keyboard  31   c , or the like. 
     The above-described reader/writer  32  has a read terminal  33  (refer to  FIG. 6 ) and reads information provided from the RF powder particles  11  to  13  using radio-frequency electromagnetic waves (RF) in a specific frequency band including 2.45 GHz by the read terminal  33 . The frequencies used in each of the plurality of RF powder particles are different from each other, and are, for example, 1.9 GHz, 2.0 GHz, and 2.54 GHz as described above. Hence, the reader/writer  32  is configured to read the electromagnetic waves of, for example, 1.5 to 3.0 GHz frequency band as the above-described specific frequency bands at proper timing. In order to read information from each of the, plurality of RF powder particles  11  to  13  in the base  10  via the read in terminal  33 , the reader/writer  32  performs a scanning operation in a certain direction along the surface of the base  10 , and also changes the frequency used for transmission/reception within the specific frequency band. 
       FIG. 5  schematically shows that a radio-frequency electromagnetic wave E with a specific frequency included in a predetermined frequency band is radiated from the read terminal  33  of the reader/writer  32 . Specifically, it shows that when the frequency of the electromagnetic wave E radiated from the read terminal  33  of the reader/writer  32  is set to 2.45 GHz, the RF powder particle  11  is being responsive to the electromagnetic wave E. At this time, neither of the other RF powder particles  12  and  13  is responsive to the electromagnetic wave with a frequency of 2.45 GHz radiated from the read terminal  33 . Here, since the wavelength of 2.45 GHz band is approximately 15 centimeters, the RF powder particles  11  to  13  are contained in a single wave, so that an electromagnetic field of the electromagnetic wave is combined with antennas to thereby cause energy transfer. It will be described in such a way that the radiated electromagnetic waves are transmitted and received seen from a distance. 
       FIG. 6  shows a state where signals (information) are transmitted and received based on the radio-frequency electromagnetic wave (frequency of 2.45 GHz given from the reader/writer  32  in an existence position of the RF powder particle  11 . Assuming that the read terminal  33  provided in the bottom surface of the reader/writer  32  performs a scanning operation by scanning movements of the reader/writer  32  and is located above the RF powder particle  11 . In this case, the read terminal  33  radiates the radio-frequency electromagnetic waves with several different frequencies, and when the electromagnetic wave of 2.45 GHz to which the RF powder particle  11  is responsive is radiated (an arrow  34  shown in  FIG. 6 ), the RF powder particle  11  receives the radio-frequency electromagnetic wave, operates the integrated circuit  15  based on energy thereof, and extracts (or writes) information from the memory  28  to radiate it as the radio-frequency electromagnetic wave (an arrow  35  shown in  FIG. 6 ). The electromagnetic wave radiated by the RF powder particle  11  is received by the read terminal  33  of the reader/writer  32 . The read terminal  33  of the reader/writer  32  transmits the information received from the RF powder particle  11  to the computer  31 , and the information provided from the RF powder particle  11  is memorized in the memory of the computer  31  in a position where there is the RF powder particle  11 . 
     Similarly, in the case where the reader/writer  32  performs scanning movements, and the read terminal  33  thereof is located above the RF powder particle  12 , when the electromagnetic wave radiated by the read terminal  33  reaches the frequency of 2.0 GHz to which the RF powder particle  12  is responsive, the RF powder particle  12  receives the radio-frequency electromagnetic wave, the integrated circuit  15  operates, and the information from the memory  28  is read (or written). Furthermore, similarly, in the case where the reader/writer  32  performs scanning movements, and the read terminal  33  thereof is located above the RF powder particle  13 , when the electromagnetic wave radiated by the read terminal  33  reaches the frequency of 1.9 GHz to which the RF powder particle  13  is responsive, the RF powder particle  13  receives the radio-frequency electromagnetic wave, the integrated circuit  15  operates, and the information from the memory  28  is read (or written). 
     By the reader/writer  32  scanning over the whole inside and surface of the base  10  shown in  FIG. 4 , position information and frequency information of the RF powder particles  11  to  13  which exist throughout a scanning area in the base  10 , and various kinds of information written in each of them are memorized in the memory of the computer  31 . The information memorized in the memory of the computer  31  is displayed on the display  31  a thereof if needed. 
     Producing bills by making the above-described RF powder particles  11  to  13  to be contained in the bills using the above-described method, or making the RF powders  11  to  13  to be contained in important documents such as official documents, licenses, insurance cards, the other important cards, or the like makes it possible to utilize the RF powder  11  for forgery discrimination of the bills, authentication of the important documents, or the like. Additionally, since the RF powder  11  is used as the powder (powdery substance) of collectively utilizing a plurality or a large number of RF powder particles instead of using it as an individual single IC tag chip in this case, the treatment is easy. 
     When the RF powder-containing base  10  is a bill, it is possible to discriminate whether or not the bill  10  is forgery based on the information displayed on the display  31   a.    
     The RF powder-containing base  10  is produced in such a way that a large quantity of the RF powder particles  11 ,  12 , and  13  separately manufactured in a predetermined RF powder manufacturing process are blended at a proper rate to produce an RF powder and the RF powder is made to be contained in the base  10 . As a manner of making the RF powder particles to be contained in the base  10 , for example, three kinds of adhesive containing aqueous solutions which respectively contain a required number of RF powder particles  11 ,  12 , and  13  are written in the bills or the like with the dropper or the like. Thus, the RF powder particles  11 ,  12 , and  13  are attached to and made to soak into a specific point. 
     In addition, the information memorized in the memory  28  of the integrated circuit  15  of the RF powder particles  11 ,  12 , and  13  may be memorized before writing it in the bills or the like, or the information may be memorized by the reader/writer  32  into the RF powder particles  11 ,  12 , and  13  contained in the bills after making the RF powder particles  11 ,  12 , and  13  to be contained in the bills or the like to then produce the bills as the RF powder-containing base  10 . 
     Note that while an example of the bills as the RF powder-containing base has been explained in the present embodiment, plastic cards such as paper for documents, business cards, credit cards may also be used other than that. For example, even for paper in which the RF powders are made to be contained to then be arranged and on which nothing is drawn, it is possible to create images on a display screen of the computer by reading the paper with the reader/writer, based on an arrangement of each RF powder particle, a frequency of the radio-frequency electromagnetic wave to which each RF powder particle is responsible, and information in the memory of each RF powder particle. 
     Meanwhile, although an example in which three kinds of RF powder particles  11 ,  12 , and  13 , but not limited to, are made to be contained in the base  10  has been explained in the present embodiment, the number of kinds of the RF powder made to be contained in the base may be not more than or not less than three. 
     Furthermore, although it has been explained in the present embodiment that a plurality kinds of RF powder particles are made to be intentionally contained in the base, the RF powder particles in which a distribution has occurred on a frequency to which the RF powder is responsible may be made to be incidentally contained in the base. 
     The RC powder containing base according to the present disclosure is utilized as bills, credit cards, documents, or the like whose forgery can be prevented.