JP2008203996A - Base body, and confirmation system of frequency response characteristic and position thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base body capable of reading a position and a frequency response characteristic of a chip by detecting variation in the resonant state of a tank circuit while combining the tank circuit having a specific resonance frequency and a modulated laser beam externally supplied. <P>SOLUTION: A powder chip (a base body) 11 includes a substrate 12, an inductance element formed thereon, a first upper electrode 16 disposed between both end electrodes of the inductance element, a first conductor film 17a facing the first end electrode of the inductance element via an insulating film, and a second conductor film 17b facing the second end electrode of the inductance element via an insulating film, wherein the first conductor film and the second conductor film include a second upper electrode disposed via a gap and a photoconductive film 20 formed on the upper face of the second upper electrode so as to cover a region including the gap. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a substrate that can be used as a powder chip and the like, and a system for confirming the existence position and frequency response characteristics of the substrate, and in particular, has a minute tank circuit and a photoconductive film made by a film forming technique, The present invention relates to a substrate whose resonance frequency is changed by irradiated laser light, and a system for confirming the existence position and frequency response characteristics of the substrate.

  At present, a wireless IC tag or a wireless IC card (hereinafter referred to as “wireless IC tag / card” when expressed in a unified manner) is considered as a product at the entrance of the ubiquitous era. For example, RFID (wireless identification) is used for applications such as identification of name tags and products, management of sorting parts / materials, intermediate products / finished products, etc. in factories, and for prepaid ticket cards that can be used repeatedly. It is used. In general, the wireless IC tag / card does not have a power source inside, and generates a direct current power source that drives a control circuit and a memory by receiving and rectifying a radio wave for a read signal from a reader / writer. When used as an RFID, a frequency of 900 MHz or 2.45 GHz is used as a radio frequency in order to secure a reading distance of several tens of centimeters to several meters. Furthermore, RFID radiates radio waves with a dipole antenna or the like. The card also has a built-in antenna that receives radiated radio waves. Similarly, an antenna that radiates radio waves for read / write signals is used for the reader / writer. By using the radiated radio wave, it is possible to read information stored in the RFID even from a distance of several tens of centimeters to several meters and sort cargo such as goods.

  In addition, the prepaid ticket card has a purpose of avoiding interference between lanes by simple control, so that a signal as low as 13.5 MHz is wirelessly transmitted so that signals can be exchanged only when the distance is several cm. A spiral coil that is used as a frequency and is much smaller than a wavelength at a radio frequency is incorporated together with a radio IC connected thereto. With this spiral coil, when the ticket card approaches, the reader / writer coil in the ticket checker is magnetically coupled to automatically exchange information necessary for ticket check work.

The price of the wireless IC tag can be reduced by reducing the size of the IC tag chip. This is because if the size of the IC tag chip is reduced, the number of IC tag chips obtained from one wafer can be increased. To date, for example, a 0.4 mm square IC tag chip has been developed. This IC tag chip can read 128-bit memory data in the chip with a microwave of 2.45 GHz (for example, see Non-Patent Document 1). However, despite the convenience of wireless IC tags, the application market is limited. It has price and technology challenges.
Mitsuo Usami, “Ultra-miniature wireless IC tag chip“ Muchip ””, Applied Physics, Vol. 73, no. 9, 2004, p. 1179-p. 1183

  For example, consider the case where a conventional IC tag is applied to a bill. In order to prevent counterfeit bills, a small circuit element (chip) having a smaller size than the IC tag is desirable. However, miniaturization of the IC tag is impossible because it has a built-in IC circuit.

  Therefore, the present inventors propose a chip including only a tank circuit. This chip can be manufactured as an element that is considerably smaller than the size of the IC tag, and is about the size of a powder particle. On the other hand, when such a chip is attached to or contained in the bill or a similar card, a reading technique for confirming the presence and characteristics of the chip is an important technique. There is a need for a practical technique for detecting the presence and characteristics of the chip in a base sheet such as a bill or a card from a remote location. Electromagnetic coupling is used to read the presence and characteristics of the chip, but the configuration of electromagnetic coupling is a technical issue.

  An object of the present invention is to detect a change in a resonance state of a tank circuit by combining a tank circuit having a specific resonance frequency and a modulated laser beam given from the outside, and to read a position where the chip exists and a frequency response characteristic. An object of the present invention is to provide a substrate that can be used.

  Another object of the present invention is to use electromagnetic waves even at a relatively distant distance without causing physical contact or proximity relations, even for fine powder chips of 1 mm or less on a base sheet. Another object of the present invention is to provide a system for confirming the existence position of a substrate and a frequency response characteristic that can stably form a coupling relationship.

  In order to achieve the above object, the substrate and the presence position of the substrate and the frequency response characteristic confirmation system according to the present invention are configured as follows.

  The substrate according to the present invention includes at least one of an inductance element and a capacitance element, a photoconductive film is provided so as to cover part or all of the inductance element and the capacitance element, and light is applied to the photoconductive film. It is configured to change the inductance of the inductance element and / or the capacitance of the capacitance element.

  In the above substrate, the electric circuit element forming the inductance element and the electric circuit element forming the capacitance element form a tank circuit, and are configured to change the resonance frequency of the tank circuit by irradiating the photoconductive film with light. The The light is preferably laser light, and the laser light is preferably pulsed laser light modulated by an on / off signal.

The above-mentioned base is a particulate powder chip that does not have connection terminals as a whole.

  In the base body (or powder chip) according to the present invention, an inductance element and a capacitance element are provided on a substrate, and a photoconductive film (or a photoconductive film) is provided so as to cover a part or all of the element. Yes. A tank circuit in which inductance and / or capacitance changes when light strikes the photoconductive film is formed. Preferably, the light is a laser beam in order to determine the arrangement position of the substrate. Since the resonance frequency of the tank circuit changes when the inductance or capacitance is changed, the change in the resonance characteristic at the position where the light hits provides information on the location of the substrate and the frequency response characteristic.

In the above substrate, both the inductance and the capacitance may be changed. However, if either one of the inductance and the capacitance is changed, the effect of the change is the same. Therefore, any simple configuration is selected. be able to.

Below, the structural example which changes the capacitance of the capacitance element in a base | substrate is demonstrated.

  The substrate according to the present invention includes a substrate, an inductance element formed on the substrate, a first upper electrode disposed between the first and second end electrodes of the inductance element, and a first of the inductance element. A second upper electrode having a first conductor portion facing the end electrode and a second conductor portion facing the second end electrode, wherein the first conductor portion and the second conductor portion are arranged with a gap therebetween; And a photoconductive film formed to cover a region including a gap on the upper surface of the second upper electrode. Based on this configuration, when the photoconductive film is not irradiated with laser light, the first tank circuit is formed by the inductance element and the first capacitance element formed by the first upper electrode, and the photoconductive film is irradiated with laser light. The second upper electrode becomes a second capacitance element connected between the first and second end electrodes of the inductance element, and the second tank is formed by the inductance element, the first capacitance element, and the second capacitance element. A circuit is formed.

  In the above configuration, the inductance element formed on the substrate is a coil. A first upper electrode is provided which forms a first capacitor as a first capacitance element connected to the first and second end electrodes constituting both ends of the coil via a dielectric. Further, in addition to the first upper electrode, the first and second end electrodes of both ends of the coil can be connected to the coil only when the laser beam hits in parallel with the first capacitor. A second upper electrode composed of two first conductor portions and a second conductor portion is provided on the top via a dielectric. A photoconductive film is formed on the upper surface of the second upper electrode. When the photoconductive film is irradiated with light, a second capacitor is formed on the second upper electrode. Based on the above configuration, when the laser beam is not irradiated from the outside, a first tank circuit is formed by the inductance element and the first capacitance element by the first capacitor. When the laser beam is irradiated, the second capacitor becomes a second capacitance element, and a second tank circuit is formed by the inductance element and the first and second capacitance elements.

In the substrate configured as described above, the first tank circuit has a first resonance frequency (f ₀ ), and the second tank circuit has a different second resonance frequency (f _n ). The frequency (f _n ) varies depending on the intensity of the laser beam or on / off.

In order to be able to respond to a high-frequency pulse laser in the substrate having the above structure, the material of the photoconductive film is preferably high-resistance GaAs with a short lifetime. Alternatively, TiO ₂ or ZnS is also a candidate, but a material that cannot be expected to have a high-speed response.

  In the substrate configured as described above, preferably, the opposing edge portions of the first and second conductor portions (second capacitor electrodes) of the second upper electrode (electrode serving as the second capacitor) have a comb shape. According to this comb shape, the connection surface is lengthened, and the two second capacitor electrodes are electrically connected with minute light to facilitate the function.

In the substrate having the above-described configuration, when the resonance frequency characteristic of the substrate is detected by the frequency spectrum of the reflection component, there is a method of detecting the difference between the reflection spectrum when the light is applied and the reflection spectrum when the light is not applied. When the amount of change is small, the difference spectrum gives a differential spectrum and can be used as a method for accurately obtaining the resonance frequency. As a method for improving the signal-to-noise ratio (SN ratio), there is a method of applying pulse modulation to the laser light. When a pulsed laser beam modulated with an on / off signal having a frequency (f ₁ ) is used, the reflected RF electromagnetic wave is a reflected wave modulated with f ₁ , so that only the frequency component of f ₁ is detected as a signal component. It is possible to determine that the signal is only at the position where the laser beam hits and to obtain a frequency spectrum with a good S / N ratio.

  In the substrate configured as described above, the inductance element is preferably a spiral coil of at least one turn formed on the insulating film surface of the substrate.

  The system for confirming the presence position and frequency response characteristics of the substrate according to the present invention is arranged so that the substrate (powder chip) arranged on the substrate sheet and the substrate sheet are magnetically coupled to the inductance element of the substrate. An antenna wire having a circular conductor wire provided, a probe antenna that is spatially separated from the base sheet and electromagnetically coupled to the antenna wire, an oscillator that outputs an oscillation signal having a frequency in a band to be examined, a reflected wave, etc. A detecting device (including a circulator) for detecting a transmitted wave (including a circulator), in which an electromagnetic wave related to an oscillation signal is incident on an antenna line on a sheet via a probe antenna, and reflected from the antenna line to a reflected wave or the like Such a signal is detected to know the position of the chip and the frequency response characteristic (spectrum). Based on this configuration, when the on-off modulated pulsed laser light is irradiated to the base on the base sheet, the detection device outputs a signal related to the reflected wave or the like in synchronization with the on / off of the laser light. To detect.

  In the system for confirming the presence position and frequency response characteristics of the base body having the above-described configuration, the detection apparatus includes an extraction unit that extracts a modulation signal related to a reflected wave or the like, and the frequency of the base body is determined from the frequency spectrum of the obtained tank circuit. The characteristics are confirmed, and the frequency is used as the ID data of the substrate together with the position information.

According to the substrate of the present invention, as a method for detecting the substrate, the frequency characteristic (spectrum) of a tank circuit having a specific resonance frequency is combined with a modulated laser beam that accurately gives positional information to the substrate (powder chip). It is possible to reliably and easily read the existing position and frequency characteristic of the.
According to the system for confirming the presence position of the substrate and the frequency response characteristic according to the present invention, the fine powder chip on the substrate sheet can emit electromagnetic waves even at a long distance without physically contacting or approaching the prober. By using the electromagnetic coupling and the magnetic coupling, the signal transmission / reception coupling relationship can be made stably, and the signal related to the reflected wave or the like is extracted by the modulation method, thereby having a predetermined resonance frequency characteristic. The substrate can be detected accurately and reliably.

  DESCRIPTION OF EMBODIMENTS Preferred embodiments (examples) of the present invention will be described below with reference to the accompanying drawings.

  An embodiment of a substrate according to the present invention will be described with reference to FIGS. In this embodiment, a powder chip is shown as an example of the substrate. 1 shows an external perspective view of the powder chip, FIG. 2 shows a plan view of the powder chip, and FIG. 3 shows a longitudinal sectional view taken along line AA in FIG. In the cross-sectional view taken along the line AA in FIG. 3, the thickness of the constituent material of the powder chip is exaggerated.

  Here, the “powder chip” is a particle that does not have an electrical connection terminal and is treated like powder (powder or granular material) without distinction between the upper and lower sides, and each particle is an electric circuit element. It means something that has and functions. The “substrate” according to the present invention is not limited to the “powder chip”.

  The powder chip 11 preferably has a shape of a cube or a plate-like rectangular parallelepiped similar to this, and with respect to a plurality of rectangular planes on the outer surface, the rectangular plane including the longest side is preferably 1 mm square or less, more preferably It has a three-dimensional shape having a size of 0.15 mm square or less. As shown in FIG. 2, the powder chip 11 of this embodiment is formed so that its planar shape is substantially square. In the powder chip 11, in a substantially square planar shape, for example, the length L of one side shown in FIG. 2 is 0.15 mm (150 μm).

In the powder chip 11, as shown in FIGS. 1 and 3, an insulating layer (oxide film SiO ₂ or the like) 13 is formed on a substrate 12 such as P-type silicon (Si). When the upper surface of the insulating layer 13 is divided into large regions, there are a region where a spiral coil 14 is formed and a region where a capacitor (or capacitor) 15 is formed. The coil 14 and the capacitor 15 can be separated as two electric circuit element parts on the insulating layer 13 formed on the surface of the substrate 12. The coil 14 functions as an inductance element, and the capacitor 15 functions as a capacitance element.

  The capacitor 15 further includes two elements, that is, a capacitor element 15-1 that always functions as a capacitance element and a pseudo capacitor element 15-2 that functions as a capacitance element depending on conditions. The capacitor element 15-1 and the pseudo capacitor element 15-2 are arranged on the upper surface of the powder chip 11 so that the geometrical positional relationship is parallel to the longitudinal direction.

  As will be described later, the capacitor element 15-1 is formed of lower electrodes (electrode pads) 14 a and 14 b formed on both ends of the coil 14, and an upper electrode 16 facing the lower electrodes (electrode pads) 14 a and 14 b. The upper electrode 16 is formed integrally with one electrode film, and always has a function as a capacitor element having a previously designed capacity. The upper electrode 16 of the capacitor element 15-1 includes, as its parts, capacitor electrode pad portions 16a and 16b located at both ends, and a photoconductive photoconductive wiring 16c connecting the two pad portions 16a and 16b located at both ends. have. The portions 16a and 16b forming the capacitor electrode pads face the two lower electrodes 14a and 14b, respectively. In the capacitor element 15-1, two capacitor elements are formed at the pad portions 16a and 16b at both ends of the upper electrode 16 based on the opposing relationship with the lower electrodes 14a and 14b.

  The pseudo capacitor element 15-2 is formed of lower electrodes 14a and 14b formed on both ends of the coil 14, and upper electrodes (17a and 17b) opposed to the lower electrodes 14a and 14b, respectively. As shown in FIGS. 1 and 2, the upper electrode of the pseudo capacitor element 15-2 includes two electrode portions 17a and 17b that are separated from each other in the plan view. The two upper electrodes 17a and 17b each have a rectangular shape, are in a positional relationship facing each other at one edge of each end, and are separated and arranged with a narrow gap G designed. Has been. In the normal state, the pseudo capacitor element 15-2 is in a state where the two upper electrodes 17a and 17b are separated from each other in an electric circuit, and does not function as a capacitor, and when a specific state as described later occurs. Only the two upper electrodes 17a and 17b are in an electric circuit-connected state, and are elements having a characteristic of generating a function as a capacitor element.

On the upper surface of the powder chip 11, a coil 14 (including pads 14 a and 14 b) is formed in an insulating layer 18 (SiO ₂ , SiN, etc.) formed on the insulating layer 13. The coil 14 and the capacitor element 15-1 have an effect of resonating at a specific resonance frequency (f ₀ ) set according to the powder chip 11. More precisely, the coil 14 forms a tank circuit with the capacitor element 15-1. If the tank circuit is coupled to a magnetic field having a frequency that causes resonance in the tank circuit, the reflection coefficient is reduced. As will be described later, when magnetic field energy is applied to the tank circuit from the outside through electromagnetic coupling between the antennas, the reflected wave of the incident electromagnetic wave is lowered.

  As shown in FIG. 1 or 2, the coil 14 is formed by, for example, triple winding a single conductor wiring along each side of the substantially square planar shape of the powder chip 11. The material of the conductor wiring that forms the coil 14 is, for example, copper (Cu).

  Both ends of the coil 14 are rectangular pads 14a and 14b having a required area. These pads 14a and 14b are portions having the function of the lower electrode described above. The two pads 14a and 14b are disposed on the inner peripheral side and the outer peripheral side of the loop-shaped coil 14, respectively. Each of the pads 14a and 14b functions as a lower electrode for both ends 16a and 16b of the upper electrode 16 of the capacitor element 15-1 and each of the two upper electrodes 17a and 17b of the pseudo capacitor element 15-2.

  In the above, the number of turns, the length, and the shape of the coil 14 can be arbitrarily set according to the target resonance frequency design.

The capacitor element 15-1 further includes two capacitor elements 15-1a and 15-1b. The capacitor element 15-1a is formed from the lower electrode 14a and the pad portion 16a (aluminum (Al) or the like) of the upper electrode 16. The capacitor 15-1b is formed from the lower electrode 14b and the pad portion 16b of the upper electrode 16. The pad portions 16a and 16b of the capacitor elements 15-1a and 15-1b are connected by a conductor wiring 16c. Actually, the two pad portions 16a and 16b and the conductor wiring 16c are formed as an integral conductor metal layer 16, that is, the upper electrode 16 described above. As shown in FIG. 3, an insulating film 19 (SiO ₂ ) as a dielectric is provided between the lower electrode 14a and the electrode portion 16a and between the lower electrode 14b and the electrode portion 16b. The insulating film 19 electrically insulates the pad portion 16a of the lower electrode 14a and the upper electrode 16 and the pad portion 16b of the lower electrode 14b and the upper electrode 16 from each other. In FIG. 1 and FIG. 2, the insulating film 19 is transparent and is not shown.

The upper surfaces of the two upper electrodes 17a and 17b forming the pseudo capacitor element 15-2 are covered with a photoconductive film (photoconductive film) 20 including the region where the gap G exists. The region covered with the photoconductive film 20 may be a region that is in contact with the upper surfaces of the two upper electrodes 17a and 17b and is capable of electrically connecting both electrodes. In FIG. 1 and FIG. 2, the formation area of the photoconductive film 20 is shown as a hatched portion. The photoconductive film 20 is a non-conductive material when not exposed to light, and is conductive when exposed to light. As a material of the photoconductive film 20, for example, there is GaAs. This material is easy to design because it also has photoconductive properties for red and can be made semi-insulating by adjusting the As component. Low-temperature growth such as spectroscopic epitaxy (MBE) is also possible, and the carrier lifetime can be nanoseconds or less, so that the upper limit of the modulation frequency of the pulse-modulated laser is afforded. TiO ₂ or ZnS can also be used. When the photoconductive film 20 is not irradiated with laser light or the like from the outside, the two upper electrodes 17a and 17b are not electrically connected, so that the pseudo capacitor element 15-2 does not function as a capacitor element. When the photoconductive film 20 is irradiated with laser light or the like from the outside, the two upper electrodes 17a and 17b are electrically connected, and the pseudo capacitor element 15-2 functions as a capacitor. At this time, the electrical resistance changes according to the intensity of light.

  The pseudo capacitor element 15-2 is composed of two capacitor elements 15-2a and 15-2b when functioning as a capacitor element. The capacitor element 15-2a is formed of the lower electrode 14a and the upper electrode 17a (aluminum (Al) or the like). The capacitor element 15-2b is formed of the lower electrode 14b and the upper electrode 17b. Between the lower electrode 14a and the upper electrode 17a and between the lower electrode 14b and the upper electrode 17b, the insulating films 19 as the dielectric are provided. The insulating film 19 electrically insulates the lower electrode 14a and the upper electrode 17a, and the lower electrode 14b and the upper electrode 17b from each other.

  Further, the intersecting portion of the conductor wiring 16c connecting the pad portions 16a and 16b of the upper electrode 16 and the coil 14 is electrically insulated by the insulating film 19 described above. Further, the intersecting portions of the upper electrodes 17 a and 17 b and the coil 24 are electrically insulated by the insulating film 19.

  With the above configuration, between the two end portions of the coil 14, in a normal state where the photoconductive film 20 is not irradiated with laser light, two capacitor elements 15-1a and 15-1b electrically connected in series are used. The capacitor element 15-1 to be made will be connected. A first tank circuit (LC resonance circuit) is formed by the coil 14 and the capacitor element 15-1 connected so as to form a loop. In this case, the tank circuit produces a sharp resonance characteristic.

  In a state where the photoconductive film 20 is irradiated with laser light, a capacitor element 15-1 made of two capacitor elements 15-1a and 15-1b electrically connected in series between both ends of the coil 14 is used. Then, the capacitor element 15-2 made of two capacitor elements 15-2a and 15-2b electrically connected in series is connected in a parallel connection relationship. A second tank circuit (LC resonance circuit) is formed by the coil 14 connected to form a loop and the parallel circuit of the capacitor elements 15-1 and 15-2. The capacity due to the parallel circuit of the two capacitor elements 15-1 and 15-2 is increased. In this case, the resonance frequency of the second tank circuit is shifted to a frequency different from the resonance frequency of the first tank circuit, the Q value is lowered, and the resonance characteristics are moderated.

FIG. 4 shows a tank circuit made up of an inductance element and a capacitance element provided in the powder chip 11 as an equivalent circuit. In the tank circuit 21, for the circuit indicated by the solid line (first tank circuit), the symbol L indicates an inductance element realized by the coil 14, and the symbol C1 is a capacitance element realized by the capacitor element 15-1. Is shown. In FIG. 4, the capacitance element C1 is represented by a series circuit of two capacitor elements. The two capacitor elements correspond to the two capacitor elements 15-1a and 15-1b described above. Further, in the circuit indicated by a two-dot chain line in FIG. 4, when the powder chip 11 is irradiated with the laser light 41 and the photoconductive film 20 has conductivity, the pseudo capacitor element 15-2 is used as a capacitor element. The circuit state in which the capacitance element C2 having the following functions and connected in parallel to the capacitance element C1 is generated is shown. In this case, the tank circuit 21 also includes a variable resistance component R corresponding to the resistance of the photoconductive film. In the tank circuit 21, a second tank circuit is formed by a circuit indicated by a solid line and a circuit indicated by a two-dot chain line. When the laser light 41 is not irradiated onto the powder chip 11, the circuit portion indicated by the two-dot chain line does not occur. Resonance frequency of the second tank circuit is assumed to be f _n.

  Next, with reference to FIGS. 5 to 9, a system for confirming the presence position and frequency response characteristics of the powder chip 11 with respect to the base sheet provided with the powder chip 11 having the above structure will be described.

  In FIG. 5, the powder chip 11 is provided at an appropriate location on the surface or inside of the base sheet 31. The structure formed on the surface of the powder chip 11 is as described above. In practice, the powder chip 11 is fine. However, in FIG. 5, the powder chip 11 is exaggerated. The base sheet 31 is, for example, a plastic sheet, paper, banknote, card or the like. With respect to the powder chip 11, a loop-shaped antenna wire 32 that is closed as a whole is provided on the surface of the base sheet 31. The antenna wire 32 is made of a conductor wire. In addition, the antenna wire 32 is formed with a part of the conductor wire portion 32 a disposed so as to surround the periphery of the powder chip 11. The circular conducting wire portion 32 a is a portion that produces a magnetic coupling action with the coil 14 on the surface of the powder chip 11.

Further, in FIG. 5, reference numeral 33 indicates a probe device. The probe device 33 is a device for detecting whether the base sheet 31 has the powder chip 11 or what the resonance frequency characteristic of the tank circuit 21 of the powder chip 11 is. In other words, this is an apparatus for confirming the presence position and frequency response characteristics of the powder chip 11 having the required resonance frequency (f ₀ ) in the base sheet 31. The probe device 33 includes an oscillator 34, a circulator 35, a coaxial line (transmission line) 36, and a probe antenna 37 formed of a looped conductor. The oscillator 34 generates a high frequency signal including the frequency f ₀ for the characteristic detection probe. The high frequency signal output from the oscillator 34 is supplied to the probe antenna 37 via the circulator 35 and the coaxial line 36. When the probe antenna 37 supplies a high-frequency signal, it emits electromagnetic waves. According to the positional relationship between the probe antenna 37 of the probe device 33 and the antenna line 32 of the base sheet 21 as shown in FIG. 5, the electromagnetic wave radiated from the probe antenna 37 is received by the antenna line 32. Further, the high-frequency signal is incident on the coil 14 of the powder chip 11 through the circuit lead portion 32 a of the antenna wire 32.

In FIG. 5, reference numeral 41 denotes a visible laser beam modulated by an ON / OFF signal, which is a pulse laser beam. Frequency of the on-off is assumed to be f _1. The pulse laser beam 41 is the same as the laser beam 41 described in FIG. In FIG. 5, for convenience of explanation, the pulsed laser light 41 is drawn so as to be focused on the powder chip 11 on the base sheet 31. Not laser light irradiating the powder chip 11 when in the OFF state in the pulse laser light 41, photo-Conductive film 20 described above has no conductivity, the resonant frequency of the tank circuit 21 is set to f _0. When the pulse laser beam 41 is in the on state, the laser beam 41 is irradiated to the powder chip 11, the photoconductive film 20 described above exhibits conductivity, and the capacitor circuit C 2 is generated in the tank circuit 21. The frequency (f _n ) is shifted from the resonance frequency f ₀ .

  In actuality, the pulsed laser light 41 is not switched between an ON state (denoted as “ON” in the figure) and an OFF state (denoted as “OFF” in the figure) that clearly changes with good rise. Usually, a transitional change occurs in the switching state.

  Next, an example of operation when the pulse laser beam 41 is irradiated to the base sheet 31 having the powder chip 11 and the antenna wire 32 in a state where the probe device 33 or the high-frequency electromagnetic wave is applied is reflected waves. From the viewpoint of The operation example in terms of the reflected wave is an example of an operation in which the antenna line 32 reflects the electromagnetic wave received from the probe antenna 37 to the probe antenna 37.

  The result of the operation example regarding a reflected wave is shown in FIG. 6 and FIG. In the graph of FIG. 6, the horizontal axis represents frequency, and the vertical axis represents reflection coefficient (dB). FIG. 7 shows a waveform example of the reflected wave.

When the pulse laser beam 41 is off and the powder chip 11 of the base sheet 31 is not irradiated with light, the tank circuit 21 is set to the resonance frequency f ₀ of the first tank circuit. The high frequency waves supplied from the probe antenna 37 and incident on the coil 14 via the antenna wire 32 and the winding conductor portion 32a are absorbed, and the reflected wave decreases from the antenna wire 32. The magnitude of the reflected wave can be detected in the output state of the branch output end 35 a of the circulator 35 in the probe device 33. This operating state is indicated by the spectral characteristic 51 of FIG. 6 and by the waveform state 61 of FIG. In FIG. 6, f ₀ is the total resonance frequency of the antenna wire 32 and the powder chip 11, and deviates from the frequency of the powder chip 11 alone.

Also when the pulse laser light 41 is light in powder chip 11 of the base sheet 31 in the on state is irradiated, the tank circuit 21 becomes the second tank circuit, the resonant frequency (vibration frequency) is shifted from the resonance frequency f ₀ Therefore, the amount of high-frequency absorption supplied from the probe antenna 37 and incident on the coil 14 via the antenna wire 32 and the loop conductor portion 32a decreases, and the reflected wave from the antenna wire 32 increases. Since the reflection coefficient changes according to the intensity of the pulsed laser light 41, the level of the reflected wave also changes according to the intensity of the light. This operating state is indicated by the characteristics 52 and 53 in FIG. 6 and by the waveform state 62 in FIG. A characteristic 52 in FIG. 6 and a waveform state 62 in FIG. 7 show an operation state when the photoconductive film has a sufficiently low resistance corresponding to strong light and operates as a switch.

  An example of the operation state when the light intensity is low is indicated by a characteristic 53 in FIG. 6 and schematically indicated by a waveform state 63 in FIG.

In the waveform example of the reflected wave 60 shown in FIG. 7, the waveform portion 60 </ b> A is a waveform of the modulated reflected wave corresponding to the resonance of the tank circuit 21. This modulated reflected wave 60A produces an envelope of 60B is modulated at a frequency _{f 1.} As described above, in the probe antenna 37 of the probe lobe device 33 that radiates the high frequency of the frequency f ₀ shown in FIG. 6 with respect to the base sheet 31, the pulse laser light 41 irradiated on the powder chip 11 is turned on / off. Accordingly, the reflected wave 60 can be extracted. In this way, a signal (reflected wave signal) related to the reflected wave can be extracted from the branch output end 35a of the circulator 35 of the probe device 33.

The frequency spectrum of the reflected wave 60 is shown in FIG. In FIG. 8, the horizontal axis indicates the frequency, and the vertical axis indicates the intensity of the reflected wave. A high-frequency signal (reflected wave) having a frequency f ₀ modulated by the frequency f ₁ includes a main band 71 (frequency f ₀ ) positioned as a carrier wave and two side bands 72 and 73 (frequency f ₀ -f) positioned on both sides. ₁ , f ₀ + f ₁ ) appears. When the frequency f ₁ of the signal for turning on / off the pulse laser beam 41 is increased, the separation between the main band and the side band is improved, and the extraction of the signal of the frequency f ₁ is ensured.

  By detecting the resonance frequency based on the signal related to the reflected wave 60 output from the branch output end 35a of the circulator 35 of the probe device 33, the existence position and the frequency response characteristic of the powder chip 11 included in the base sheet 31 are known. be able to. Thus, information on the resonance characteristics (resonance frequency, etc.) of the tank circuit of the powder chip 11 added to the base sheet 31 can be obtained.

  The principle of the above frequency characteristic extraction apparatus will be described with reference to FIGS. 9A and 9B. In FIG. 9, (A) shows the spectrum of the reflected wave, and (B) shows the modulation spectrum.

In FIG. 9A, the horizontal axis indicates the frequency, and the vertical axis indicates the reflection coefficient of the reflected wave. In the characteristics shown 81 in FIG. 9 (A), the resonance frequency f ₀ is given by the peak position.

The modulation spectrum 82 shown in FIG. 9B shows the one side band (f ₀ −f ₁₎ of the reflected high frequency when the resonance characteristic of the tank circuit of the powder chip 11 is modulated by the pulse laser beam 41 having the frequency f _1. ) Is a frequency spectrum of a modulated wave obtained by demodulating. Since the modulation applied with light operates to shift the resonance frequency characteristic, the frequency spectrum 82 is obtained as a spectrum obtained by differentiating the spectrum 81 with respect to the frequency. Since there is only f ₁ component, this spectrum 82 is a signal from the powder chip 11 modulated by the pulse laser beam 41. If the modulation method is not employed, the reflected wave from the probe antenna 37 includes its own large reflected wave, so it is difficult to observe a small reflected component due to the resonance characteristics of the powder chip 11 from the absolute value of the output from the circulator 35. It is. However, according to the modulation method, the f ₁ component can be separated from other components. In FIG. 9B, the resonance frequency of the powder chip 11 can be defined as the frequency at which the spectrum crosses zero. Determining the peak position causes an error, but the frequency at which the spectrum sharply crosses zero can be read much more accurately. This increases the value as the size of significant figures when using the resonance frequency of the powder chip 11 having a different frequency as data. If, for example, three powder chips 11 having different frequency characteristics are arranged side by side and the frequency is used as an ID, if it is a two-digit significant number, it will be the cube of 100, that is, a six-digit significant number ID, but a three-digit significant number Then, it becomes 1000 to the third power, that is, the 9-digit number ID expression.

  Next, another embodiment of the powder chip according to the present invention will be described with reference to FIG. FIG. 10 shows a plan view of a powder tip 91 similar to FIG. 10, elements that are substantially the same as the elements described in FIG. In the pseudo capacitor element 15-2 of the powder chip 91 according to this embodiment, the edge shape of the opposing sides of the two upper electrodes 92a and 92b has a comb shape, and the two upper electrodes 92a and 92b have a comb shape. A meandering slit gap 93 is formed therebetween. The slit gap 93 includes a number of parallel slit portions. The slit gap 93 is made as narrow as possible, and the overall length and area of the gap are increased by the meandering shape. The number of each slit in the meandering slit gap 93 is arbitrary, for example, 250. The length of each slit forming the slit gap 93 is 100 μm, for example. The meandering shape of the slit gap 93 increases the distance of the gap.

  The region where the slit gap 93 is formed can be made as a region portion having a wide area by increasing the length of the side of each of the opposing portions of the upper electrodes 92a and 92b.

  Furthermore, as another modified embodiment of the powder chip according to the present invention, the upper and lower positions of the coil 14 and each electrode or electrode pad of the capacitor element 15-1 and the pseudo capacitor element 15-2 on the surface of the powder chip You can also reverse the relationship.

  In the description of the above embodiment, the capacitance of the capacitance element of the tank circuit 21 formed on the powder chip 11 is changed by the photoconductive film and light irradiation, and the tank circuit frequency is changed. However, the length of the coil is changed. The frequency of the tank circuit can be changed by changing the inductance of the inductance element, for example, by causing a leak between lines.

  The configurations, shapes, sizes, and arrangement relationships described in the above embodiments are merely schematically shown to the extent that the present invention can be understood and implemented. Therefore, the present invention is not limited to the described embodiments, and can be variously modified without departing from the scope of the technical idea shown in the claims.

  For example, in the present embodiment, an example of detection based on a reflected wave has been shown, but the same effect can be achieved even with an example of detection based on an absorptance or transmittance.

  The substrate, powder chip, or the like according to the present invention is added to paper, thin plastics, bills, or the like by an inexpensive method, and is used to specify paper or prevent forgery of bills.

It is a perspective view of a base (powder chip) according to an embodiment of the present invention. It is a top view of the powder chip concerning this embodiment. It is the sectional view on the AA line in FIG. It is an electric circuit diagram which shows the equivalent circuit of the tank circuit formed in the powder chip concerning this embodiment. It is a figure which shows the structure of the system which confirms the presence position and frequency response characteristic of the said powder chip | tip of the base material sheet provided with the powder chip | tip. It is a characteristic view which shows the generation | occurrence | production state of the reflected wave of a powder chip. It is a wave form diagram which shows the change state of a modulation | alteration reflected wave. It is a characteristic view which shows the frequency spectrum regarding a reflected wave. It is a figure for demonstrating the principle of a detection of a reflected wave. It is a top view of the powder chip concerning other embodiments of the present invention.

Explanation of symbols

11 Powder chip (base)
12 Substrate 13 Insulating layer 14 Coil 15 Capacitor
15-1 Capacitor element 15-2 Pseudo capacitor element 16 Upper electrode 17a, 17b Upper electrode 18 Insulating layer 19 Insulating layer 20 Photoconductive film (photoconductive film)
21 Tank circuit 31 Base sheet 32 Antenna wire 33 Probe device 37 Probe antenna 41 Pulse laser beam

Claims (14)

  At least one of an inductance element and a capacitance element is provided, a photoconductive film is provided so as to cover part or all of the inductance element and the capacitance element, and light of the photoconductive film is irradiated to emit light. Substrate characterized by varying inductance and / or capacitance of said capacitance element.   The electrical circuit element forming the inductance element and the electrical circuit element forming the capacitance element form a tank circuit, and the resonance frequency of the tank circuit is changed by irradiating the photoconductive film with the light. Item 4. The substrate according to Item 1.   3. The substrate according to claim 1, wherein the light is a laser beam.   4. The substrate according to claim 3, wherein the laser beam is a pulsed laser beam modulated by an on / off signal.   The substrate according to any one of claims 1 to 4, wherein the whole form is a particulate powder chip having no connection terminal. A substrate,
An inductance element formed on the substrate;
A first upper electrode disposed between the first and second end electrodes of the inductance element;
The inductance element has a first conductor portion that faces the first end electrode and a second conductor portion that faces the second end electrode, and the first conductor portion and the second conductor portion have a gap therebetween. A second upper electrode arranged
A photoconductive film formed so as to cover a region including the gap on the upper surface of the second upper electrode,
When the photoconductive film is not irradiated with laser light, a first tank circuit is formed by the inductance element and a first capacitance element by the first upper electrode,
When the photoconductive film is irradiated with laser light, the second upper electrode becomes a second capacitance element connected between the first and second end electrodes of the inductance element, and the inductance element; A base body characterized in that a second tank circuit is formed by the first capacitance element and the second capacitance element. The first tank circuit has a first resonance frequency (f ₀ ), and the second tank circuit has a second resonance frequency (f _n ) different from the first resonance frequency (f ₀ ). The substrate according to claim 6, wherein the second resonance frequency (f _n ) changes according to on / off of the laser beam. Claim 6 or 7 substrate, wherein the material of the photoconductive layer is GaAs or TiO _2.   The edge part which each said 1st conductor film and said 2nd conductor film opposes in said 2nd upper side electrode has a comb shape, It is any one of Claims 6-8 characterized by the above-mentioned. Substrate. The substrate according to any one of claims 6 to 9, wherein the laser beam is a pulsed laser beam modulated by an on / off signal having a frequency (f ₁ ).   The base body according to claim 6, wherein the inductance element is at least one spiral coil formed on an insulating film of the substrate.   The substrate according to any one of claims 6 to 11, wherein the whole form is a particulate powder chip having no connection terminal. A substrate according to claim 1 or 6 disposed on a substrate sheet;
An antenna wire disposed on the base sheet and having a circular conductor wire provided to be magnetically coupled to the inductance element of the base;
A probe antenna that is spatially separated from the base sheet and electromagnetically coupled to the antenna line; and an oscillator that outputs a probe signal to the probe antenna, the electromagnetic wave based on the oscillation signal being transmitted by the probe antenna. A detector that is incident on an antenna line and detects a signal from the antenna line,
When the pulsed laser light modulated by the on / off signal is applied as the laser light to the base on the base sheet, the detection device detects a corresponding signal when the laser light is turned on / off. A system for checking the presence position and frequency response characteristics of a substrate characterized by   The said detection apparatus is provided with the extraction means which extracts a modulation signal, The frequency characteristic of the said base | substrate is confirmed from the frequency spectrum of the obtained tank circuit, The presence of the said base | substrate is confirmed. A system for checking the position of the substrate and frequency response characteristics.

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