Patent Abstract:
In the field of portable electronic devices in the future, portable electronic devices will be desired, which are smaller and more lightweight and can be used for a long time period by one-time charging, as apparent from provision of one-segment partial reception service “1-seg” of terrestrial digital broadcasting that covers the mobile objects such as a cellular phone. Therefore, the need for a power storage device is increased, which is small and lightweight and capable of being charged without receiving power from commercial power. The power storage device includes an antenna for receiving an electromagnetic wave, a capacitor for storing power, and a circuit for controlling store and supply of the power. When the antenna, the capacitor, and the control circuit are integrally formed and thinned, a structural body formed of ceramics or the like is partially used. A circuit for storing power of an electromagnetic wave received at the antenna in a capacitor and a control circuit for arbitrarily discharging the stored power are provided, whereby lifetime of the power storage device can be extended.

Full Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a power storage device capable of being charged without receiving power from commercial power. 
         [0003]    2. Description of the Related Art 
         [0004]    Electronic devices such as a cellular phone, a mobile computer, a digital camera, and a digital audio player have been advanced to be downsized, and a large variety of products have been shipped to the market. In such portable electronic devices, a secondary battery as a power supply for driving is incorporated. As a secondary battery, a lithium-ion battery, a nickel-hydrogen battery, or the like is used. The secondary battery is charged by receiving power from commercial power. For example, a user connects an AC adapter to a household plug socket deposited in each home to charge the secondary battery. 
         [0005]    Although portable electronic devices are convenient, the hour of use is restricted by the capacity of the secondary battery. The user of the electronic device needs to pay attention to remaining battery level of the secondary battery and to be always conscious of the charging time. Further, the charging plugs of the electronic devices are different for each device or for each model. Therefore, many AC adapters are required to be possessed. 
         [0006]    In contrast, a power storage device is disclosed, in which a permanent magnet is moved back and forth in a slide where a coil is rolled to generate electromagnetic induced electromotive force, whereby the power storage device is charged (for example, Reference 1: Japanese Published Patent Application No. 2006-149163 (FIG. 1, and p. 4)). According to this device, power storage devices are considered to be capable of being charged without receiving power from commercial power supply. 
       SUMMARY OF THE INVENTION 
       [0007]    However, the power storage device utilizing electromagnetic induced electromotive force generated by a coil and a permanent magnet needs a movable portion, and therefore, downsizing of the power storage device is structurally difficult. Moreover, such a power storage device is required to move the magnet as well as to possess it, and the weight of the device is increased because the permanent magnet is used. Therefore, the conventional power storage device has a problem that the volume and the weight thereof are increased, and portability is lost. 
         [0008]    Incidentally, in the field of portable electronic devices in the future, portable electronic devices will be desired, which are smaller and more lightweight and can be used for a long time period by one-time charging, as apparent from provision of one-segment partial reception service “1-seg” of terrestrial digital broadcasting that covers the mobile objects such as a cellular phone. Therefore, the need for the power storage device is increased, which is small and lightweight and capable of being charged without receiving power from commercial power. 
         [0009]    It is an object of the present invention to provide a power storage device that can be charged without receiving power from commercial power, in which the charging is performed easily while reduction in size and weight or reduction in weight and thickness is achieved. It is another object of the present invention to maintain durability and required functions in the case where such a power storage device becomes small and downsized. 
         [0010]    The present invention is to provide a power storage device including an antenna for receiving an electromagnetic wave, a capacitor for storing power, and a circuit for controlling store and supply of power. In a case where the antenna, the capacitor, and the control circuit are integrally formed and thinned, a structural body formed of ceramics or the like is used for part of the integral structure. 
         [0011]    The structural body formed of ceramics or the like has resistance to pressing force or bending stress applied from outside. Therefore, in the case of thinning the antenna and the control circuit, the structural body formed of ceramics or the like serves as a protector. In addition, this structural body can have a function as a capacitor. 
         [0012]    According to the present invention, a circuit for storing power of an electromagnetic wave received at an antenna in a capacitor and a control circuit for discharging the given power are provided, whereby lifetime of the power storage device can be extended. 
         [0013]    When the structural body formed of ceramics or the like is used for part of the power storage device, rigidity can be improved. Accordingly, even when the power storage device is thinned, durability and required functions can be maintained. 
         [0014]    For example, even when pressing force is applied with a pointed object such as a tip of a pen, malfunction due to stress applied to the capacitor and the control circuit can be prevented. Moreover, resistance to bending stress can also be provided. In addition, when a wiring for connection is formed in the structural body formed of ceramics or the like so that the antenna and the control circuit are connected, malfunction caused by detachment of a connection portion can be prevented even when bending stress is applied. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0015]      FIG. 1  is a plan view showing one mode of a power storage device of the present invention. 
           [0016]      FIG. 2  is a cross-sectional view showing an example of a structure taken along a line A-B of  FIG. 1 . 
           [0017]      FIG. 3  is a cross-sectional view showing an example of a structure taken along a line A-B of  FIG. 1 . 
           [0018]      FIGS. 4A to 4C  are plan views showing an example of a power storage device that includes a first structural body provided with an antenna, a second structural body provided with a capacitor, and a power supply control circuit. 
           [0019]      FIGS. 5A and 5B  are cross-sectional views showing an example of a power storage device that includes a first structural body provided with an antenna, a second structural body provided with a capacitor, and a power supply control circuit. 
           [0020]      FIGS. 6A to 6D  are plan views showing an example of a power storage device that includes a first structural body provided with an antenna, a second structural body provided with a capacitor, a power supply control circuit, and a ceramics antenna. 
           [0021]      FIGS. 7A and 7B  are cross-sectional views showing an example of a power storage device that includes a first structural body provided with an antenna, a second structural body provided with a capacitor, a power supply control circuit, and a ceramics antenna. 
           [0022]      FIG. 8  is a view showing an example of a power supply control circuit in a power storage device. 
           [0023]      FIG. 9  is a view showing an output waveform of a low-frequency signal generation circuit. 
           [0024]      FIG. 10  is a view showing a structure of a low-frequency signal generation circuit of a power supply control circuit in a power storage device. 
           [0025]      FIG. 11  is a timing chart of a signal output from the low-frequency signal generation circuit shown in  FIG. 10 . 
           [0026]      FIG. 12  is a diagram showing a structure of a power supply circuit of a power supply control circuit in a power storage device. 
           [0027]      FIG. 13  is a view showing a structure of a power storage device provided with a plurality of antennas. 
           [0028]      FIG. 14  is a view showing a structure of a power storage device having a function of controlling supply of power stored in a capacitor. 
           [0029]      FIG. 15  is a view showing a structure of a control circuit of a power supply control circuit in a power storage device. 
           [0030]      FIG. 16  is a view showing a structure of a voltage-comparing circuit of a power supply control circuit in a power storage device. 
           [0031]      FIG. 17  is a cross-sectional view for explaining a structure of a thin film transistor used for forming a power supply control circuit. 
           [0032]      FIG. 18  is a cross-sectional view for explaining a structure of a MOS transistor used for forming a power supply control circuit. 
           [0033]      FIG. 19  is a block diagram showing a structure of an active wireless tag. 
           [0034]      FIG. 20  is a view showing an example of distribution management using an active wireless tag. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0035]    Hereinafter, an embodiment mode and embodiments of the present invention is described below with reference to the accompanying drawings. Note that the present invention is not limited to the following description and it is easily understood by those skilled in the art that modes and details can be modified in various ways without departing from the purpose and the scope of the present invention. Accordingly, the present invention should not be interpreted as being limited to the description of the embodiment mode below. Note that like portions in the drawings may be denoted by the like reference numerals in a structure of the present invention to be given below. 
         [0036]    A power storage device of the present invention includes a first structural body provided with an antenna, a power supply control circuit formed using a semiconductor layer interposed between insulating layers that are provided over and below the semiconductor layer, and a second structural body provided with a capacitor and having higher rigidity than the first structural body. This second structural body includes at least a dielectric layer inside, and the capacitor is preferably formed using the dielectric layer. The second structural body is formed of ceramics or the like, which has high rigidity, whereby mechanical strength of the power storage device can be maintained even when the power supply control circuit is thinned. 
         [0037]      FIG. 1  shows one mode of such a power storage device. A first structural body  10  is fowled of an insulating material. The thickness of the first structural body  10  is 1 μm to 100 μm, preferably, 5 μm to 30 μm. As the insulating material, a plastic sheet, a plastic film, a glass epoxy resin, a glass plate, paper, a nonwoven fabric, or other variety of objects can be used. An antenna  16  is formed using a conductive material at least on one of surfaces of the first structural body  10 . A structure of the antenna is preferably differentiated depending on a frequency band of an electromagnetic wave used by the power storage device. The antenna may have a suitable shape for a frequency band, when a frequency in a short wave band (electromagnetic wave with frequency of 1 to 30 MHz), an ultrashort wave band (electromagnetic wave with frequency of 30 to 300 MHz), or a microwave band (electromagnetic wave with frequency of 0.3 to 3 GHz) is used.  FIG. 1  shows a dipole antenna, which is suited for communication in the ultrashort wave band and the microwave band. A monopole antenna, a patch antenna, a spiral antenna, a loop antenna, or the like can be used as the antenna, other than the dipole antenna shown in  FIG. 1 . 
         [0038]    The antenna  16  is provided with an antenna terminal  18  in order to be connected to a power supply control circuit  14 . The power supply control circuit  14  is formed so that at least a part thereof overlaps with the first structural body  10 . A second structural body  12  is used as a connector for tightening connection of the first structural body  10  and the power supply control circuit  14 . 
         [0039]      FIG. 2  shows a cross-sectional structure of the power storage device taken along a line A-B of  FIG. 1 . The second structural body  12  is located to face one side on which the antenna terminal  18  of the first structural body  10  is formed. The power supply control circuit  14  is located to face the other side of the second structural body  12 . A through electrode  20  is formed in the second structural body  12  at a position corresponding to that of the antenna terminal  18 . The through electrode  20  is formed so as to be connected to a connection electrode  24  of the power supply control circuit  14  on the other side of the second structural body  12 . The through electrode  20  is formed using a metal foil or metal paste in a through hole formed in the second structural body  12 . 
         [0040]    The second structural body  12  has a thickness of 0.1 μm to 50 μm, preferably 5 μm to 30 μm, and is preferably harder than the first structural body  10 . In addition, the second structural body  12  preferably has toughness and elasticity to certain bending stress. This is because in a case where the first structural body  10  is formed of a flexible material such as a plastic film or a nonwoven fabric, bending stress can be dispersed when the second structural body  12  has uniform elasticity. Accordingly, disconnection failure between the antenna teiininal  18  and the connection electrode  24  which are connected via the through electrode  20  can be prevented. In addition, when the through electrode  20  is formed in the second structural body  12 , the power supply control circuit  14  can be downsized. 
         [0041]    As the second structural body  12 , an insulating substance such as hard plastics or glass can be used, and in particular, the ceramic material is preferably used. This is because the ceramic material realizes the foregoing characteristics and therefore, the material to be used can be selected from a wide range of materials. Further, a plurality of ceramics can be combined to be a compound. 
         [0042]    As a typical example of the ceramic material, alumina (Al 2 O 3 ) is preferably used as a highly insulating material. In addition, barium titanate (BaTiO 3 ) is preferably used as a high capacitance material. When mechanical strength has higher priority, alumina (Al 2 O 3 ), titanium oxide (TiO x ), silicon carbide (SiC), tempered glass, or crystallized glass is preferably used. In addition, when composite ceramics in which nanoparticles of SiC are added to Si 3 N 4 , or composite ceramics which contains hexagonal system BN is used, high strength, oxidation resistance, and high toughness can be obtained, which is preferable. 
         [0043]    These ceramic materials may be used to form a stacked layer structure of a plurality of layers each having a thickness of 0.1 μm to 2 μm in the second structural body  12 . In other words, it is preferable that a stacked-layer substrate be formed and an electrode be formed in each layer to form a stacked layer capacitor in the second structural body  12 . 
         [0044]    The power supply control circuit  14  is formed using an active element formed of a semiconductor layer having a thickness of 5 nm to 500 nm, preferably, 30 nm to 150 nm. Over and below the semiconductor layer, insulating layers are provided. These insulating layers are formed as layers for protecting the semiconductor layer. In addition, they may be used as a functional layer such as a gate insulating layer. A typical example of an active element is a field-effect transistor. Since the semiconductor layer is a thin film as described above, a field-effect transistor formed here is also referred to as a thin film transistor. The semiconductor layer is preferably a crystalline semiconductor layer that is crystallized by heat treatment or energy beam irradiation with a laser beam or the like, after a semiconductor layer is formed by a vapor deposition method, a sputtering method, or the like. This is because when a crystalline semiconductor layer is formed, field-effect mobility of the field-effect transistor becomes 30 to 500 cm 2 /V·sec (electron), which suppresses power loss. 
         [0045]    The power supply control circuit  14  includes a semiconductor layer, an insulating layer, a layer for forming a wiring, and is preferably formed to have a thickness of 0.5 μM to 5 μm in total. When the power supply control circuit  14  is formed to have this thickness, the power supply control circuit  14  can contribute to reduction in thickness of the power storage device. Further, the power supply control circuit  14  can have resistance to bending stress. When the semiconductor layer is separated to be island-shaped semiconductor layers, resistance to bending stress can be improved. 
         [0046]    The first structural body  10  and the second structural body  12  are fixed by an adhesive  28  so that the antenna terminal  18  and the through electrode  20  are electrically connected. For example, as the adhesive  28 , an acrylic-based, urethane-based, or epoxy-based adhesive, in which conductive particles are dispersed, can be used. Alternatively, a connection portion of the antenna terminal  18  and the through electrode  20  may be fixed by a conductive paste or a solder paste and another part may be fixed by acrylic-based, urethane-based, or epoxy-based adhesive. Also, the second structural body  12  and the power supply control circuit  14  are fixed so that the through electrode  20  and the connection electrode  24  are electrically connected. 
         [0047]    A sealant  30  is formed using an acrylic-based, urethane-based, phenol-based, epoxy-based, or silicone-based resin material and is preferably provided in order to protect the power supply control circuit  14 . The sealant  30  is formed to cover the power supply control circuit  14  and to preferably cover side surfaces of the power supply control circuit  14  and the second structural body  12 . When the sealant  30  is provided, the power supply control circuit  14  can be prevented from being damaged. Further, the adhesive strength between the power supply control circuit  14 , the second structural body  12 , and the first structural body  10  can be enhanced. In such a way, a power storage device with a thickness of 2 μm to 150 μm, preferably, 10 μm to 60 μm can be obtained. 
         [0048]      FIG. 3  shows a structure in which the antenna terminal  18  of the first structural body  10  and the connection electrode  24  of the power supply control circuit  14  are located to face and be connected to each other. The second structural body  12  is located on a back side of the power supply control circuit  14  so as to protect the power supply control circuit  14 . In a case where the second structural body  12  is provided with a capacitor, a ceramics antenna-connection electrode  27  may be formed in the power supply control circuit  14  so as to be electrically connected to a capacitor external electrode  22  of the second structural body  12 . The first structural body  10 , the second structural body  12 , and the power supply control circuit  14  are preferably fixed by the adhesive  28 . In a structure shown in  FIG. 3 , since the second structural body  12  is located on the back side of the power supply control circuit  14 , the sealant  30  may be provided as appropriate. 
         [0049]    As described above, according to the present invention, when the structural body formed of ceramics or the like is used, rigidity of the power storage device can be improved. Accordingly, even when the power storage device is thinned, durability and required functions can be maintained. When a wiring for connection is formed in the structural body formed of ceramics or the like and an antenna and a power supply control circuit are connected, malfunction caused by detachment of a connection portion can be prevented even when bending stress is applied. 
       Embodiment 1 
       [0050]    This embodiment will explain an example of a power storage device that includes a first structural body provided with an antenna, a second structural body provided with a capacitor, and a power supply control circuit  14 , with reference to FIGS.  4 A to  4 C and  FIGS. 5A and 5B .  FIGS. 4A to 4C  are plan views of the power storage device, and  FIGS. 5A and 5B  are cross-sectional views taken along lines A-B and C-D of  FIG. 4A . 
         [0051]      FIG. 4A  shows a mode in which an antenna  16  having a coil-shape is formed in a first structural body  10 . The first structural body  10  is formed using a plastic material such as PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PES (polyethersulfone), polypropylene, polypropylene sulfide, polycarbonate, polyether imide, polyphenylene sulfide, polyphenylene oxide, polysulfone, polyphthalamide, acrylic, or polyimide, or an insulating material such as nonwoven fabric, or paper. 
         [0052]    The antenna  16  is formed in the first structural body  10  using a low resistance metal material such as copper, silver, or aluminum, by a printing method, a plating method, or the like. The antenna  16  shown in  FIG. 4A  has a coil-shape which is suitable when an electromagnetic induction method (for example, 13.56 MHz band) is employed. When a microwave method (for example, an UHF band (860 to 960 MHz band), 2.45 GHz band, or the like) is employed, a length and a shape of a conductive layer serving as antenna may be appropriately set in consideration of a wavelength of an electromagnetic wave that is used for transmitting signals. In this case, a monopole antenna, a dipole antenna, a patch antenna, and the like may be used. 
         [0053]      FIG. 4A  shows a mode in which a second structural body  12  and a power supply circuit  14  are provided in accordance with an antenna terminal  18 .  FIG. 4B  is a plan view of the second structural body  12 , and  FIG. 4C  is a plan view of the power control circuit  14 . An outside dimension of the second structural body  12  and that of the power supply control circuit  14  are preferably almost the same. Alternatively, the outside dimension of the power supply control circuit  14  may be smaller than that of the second structural body  12 . 
         [0054]    In this embodiment, the second structural body  12  is preferably formed of a ceramic material. In this second structural body  12 , a through electrode  20  and a capacitor electrode  34  are formed. In the power supply control circuit  14 , a connection electrode  24  that is connected to the antenna terminal  18  and a capacitor-portion connection electrode  26  that is connected to the capacitor electrode  34  are formed. Subsequently, the details of a connection structure of the second structural body  12  and the power supply control circuit  14  is explained with reference to  FIGS. 5A and 5B . 
         [0055]      FIG. 5A  is a cross-sectional view taken along a line A-B. The first structural body  10  and the power supply control circuit  14  are connected to each other by the through electrode  20  formed in the second structural body  12 . They are fixed by an adhesive  28 . In the second structural body  12 , layers each including a dielectric layer  32  and the capacitor electrode  34  are stacked so as to be engaged with each other. A capacitor is formed by stacking the dielectric layer  32  and the capacitor electrode  34  in such a manner. 
         [0056]    The dielectric layer  32  is formed by coating a surface of the substrate with a ceramics paste in which a ceramic material such as barium titanate (BaTiO 3 ), strontium titanate (SrTiO 3 ), or a Pb-based complex perovskites compound material contains a binder compound, a plasticizer, and an organic solvent. Then, an electrode paste selected from copper or a copper alloy, nickel or a nickel alloy, silver or a silver alloy, and tin or a tin alloy, is printed thereover to form the capacitor electrode  34 . Note that when the through electrode  20  is formed, the dielectric layer and the capacitor electrode are formed to have an opening in a corresponding position where the through electrode  20  is formed. The dielectric layer and the capacitor electrode are dried, and then, cut into predetermined shapes. Then, the capacitor electrodes  34  are stacked to be engaged with each other. The stacked layers are interposed between protective layers  36  formed of a ceramic material or the like, the binder is removed, and baking and heating treatment are performed to form the capacitor. 
         [0057]    In  FIGS. 5A and 5B , the dielectric layer  32  and the capacitor electrode  34  can be fowled to have a thickness of 1 to 10 μm by using nanoparticles. Accordingly, when five dielectric layers  32  each having a thickness of 2 μm are stacked, the thickness thereof is 10 μm. Further, even when ten dielectric layers  32  each having a thickness of 1 μm are stacked, the thickness thereof is not greater than 10 μm. 
         [0058]      FIG. 5B  is a cross-sectional view taken along a line C-D and shows a structure of the capacitor electrode  34  and the capacitor-portion connection electrode  26  of the power supply control circuit  14 . In the second structural body  12 , a capacitor external electrode  22 , which is formed in an outer edge portion, is subjected to nickel plating, tin plating, and the like The adhesive  28  can be used for connecting the capacitor external electrode  22  and the capacitor-portion connection electrode  26 . 
         [0059]    As descried above, the power storage device that includes the first structural body  10  provided with an antenna, the second structural body  12  provided with a capacitor, and the power supply control circuit  14  can be obtained. When the second structural body  12  formed of ceramics or the like is used, rigidity of the power storage device can be improved. Accordingly, even when a power storage device including the power supply control circuit  14  is thinned, durability and required functions can be maintained. 
       Embodiment 2 
       [0060]    This embodiment will explain an example of a power storage device of the present invention provided with a plurality of antennas. An example of a power storage device will be explained with reference to  FIGS. 6A to 6D  and  FIGS. 7A and 7B , which includes a first structural body  10  provided with an antenna, a second structural body  12  provided with a capacitor, a power supply control circuit  14 , and a ceramics antenna  38 .  FIGS. 6A to 6D  are plan views of the power storage device, and  FIGS. 7A and 7B  are cross-sectional views taken along lines E-F and G-H. 
         [0061]    In  FIG. 6A , an antenna  16  having a coil-shape is formed in the first structural body  10 . The shape of the antenna  16  may be appropriately set in accordance with a frequency band that is used for communication, similarly to in Embodiment 1. 
         [0062]      FIG. 6A  shows a mode in which the second structural body  12 , the power supply control circuit  14 , and the ceramics antenna  38  are provided in accordance with an antenna terminal  18 .  FIG. 6B  is a plan view of the second structural body  12 ,  FIG. 6C  is a plan view of the power supply control circuit  14 , and  FIG. 6D  is a plan view of the ceramics antenna  38 . Outside dimensions of the second structural body  12 , the power supply control circuit  14 , and the ceramics antenna  38  are preferably almost the same. Alternatively, the outside dimension of the power supply control circuit  14  may be smaller than those of the second structural body  12  and the ceramics antenna  38 . 
         [0063]    In the second structural body  12  that is formed of a ceramic material, a through electrode  20  and a capacitor external electrode  22  are formed. In the power supply control circuit  14 , a connection electrode  24  that is connected to the antenna terminal  18 , a capacitor-portion connection electrode  26  that is connected to the capacitor external electrode  22 , and a ceramics antenna-connection electrode  27  that is connected to the ceramics antenna  38  are formed. Subsequently, the details of connection structures of the second structural body  12  and the power supply control circuit  14  are explained with reference to  FIGS. 7A and 7B . 
         [0064]      FIG. 7A  is a cross-sectional view taken along a line E-F. In the second structural body  12 , a capacitor is formed using a ceramic material, similarly to Embodiment 1. The structure including the through electrode  20  that connects the antenna terminal  18  of the first structural body  10  and the connection electrode  24  of the power supply control circuit  14 , is similar to that of  FIG. 5A . The ceramics antenna  38  is located on the back side of the power supply control circuit  14 . The second structural body  12  and the ceramics antenna  38 , sandwiching the power supply control circuit  14 , have a function for a protective layer. 
         [0065]      FIG. 7B  is a cross-sectional view taken along a line G-H and shows a connection structure between the power supply control circuit  14  and the ceramics antenna  38 . The ceramics antenna  38  includes a ground body  44  on one side of a dielectric substance  42  (the power supply control circuit  14  side) and a reflector  46  on the other side. The power supply control circuit  14  is provided with the ceramics antenna-connection electrode  27  to which the ground body  44  and a power feeding body  40  are connected. The reflector  46  may have a slit to enhance directivity. The reflector  46  and the power feeding body  40  are provided with a gap therebetween and are capacitive coupled. 
         [0066]    In the power storage device of this embodiment, the antenna  16  formed in the first structural body  10  and the ceramics antenna  38  are used as an antenna for power feeding, and the power is stored in the capacitor formed in the second structural body  12 . The capacitor includes dielectric layers  32  and capacitor electrodes  34 . Large capacitance can be obtained by stacking a plurality of dielectric layers  32  and capacitor electrodes  34 . In this case, frequencies of an electromagnetic wave received at the antenna  16  and the ceramics antenna  38  are varied, whereby the capacitor can be efficiently charged. In other words, a band of the electromagnetic wave received for charging the capacitor can be extended. In this case, the dielectric layer  32  and the capacitor electrode  34  can be formed to have a thickness of 1 to 10 μm by using nanoparticles. Accordingly, when five dielectric layers  32  each having a thickness of 2 are stacked, the thickness thereof is 10 μm. Further, even when ten dielectric layers  32  each having a thickness of 1 μm are stacked, the thickness thereof is not greater than 10 μm. 
         [0067]    As described above, the power storage device including the first structural body  10  provided with an antenna; the second structural body  12  provided with a capacitor, the power supply control circuit  14 , and the ceramics antenna  38  can be obtained. When the second structural body  12  formed of ceramics or the like and the ceramics antenna  38  are used, rigidity of the power storage device can be improved. Accordingly, even when a power storage device including the power supply control circuit  14  is thinned, durability and required functions can be maintained. 
       Embodiment 3 
       [0068]    An example of a power supply control circuit of a power storage device of the present invention will be explained with the use of a block diagram shown in  FIG. 8 . 
         [0069]    A power storage device  100  of  FIG. 8  includes an antenna  102 , a power supply control circuit  104 , and a capacitor  106 . The power supply control circuit  104  includes a rectifier circuit  108 , a low-frequency signal generation circuit  110 , a switching circuit  112 , and a power supply circuit  114 . Power is output from the power supply circuit in the power supply control circuit to a load  118  on the outside of the power storage device. 
         [0070]    The antenna  102  is formed in the first structural body  10  in accordance with Embodiment 1. The capacitor  106  is formed in the second structural body  12 . The power supply control circuit  104  corresponds to the power supply control circuit  14 . 
         [0071]    A structure of the load  118  in  FIG. 8  is different depending on electronic devices. For example, in the cellular phones and the digital video cameras, a logic circuit, an amplifier circuit, a memory controller, and the like correspond to a load. Also, in IC cards, IC tags, and the like, a high-frequency circuit, a logic circuit, and the like correspond to a load. 
         [0072]    Further,  FIG. 8  is the power storage device  100  having a structure in which an electromagnetic wave supplied by a power feeder  120  is received at the antenna  102  and stored in the capacitor  106 . In  FIG. 8 , the electromagnetic wave received at the antenna  102  is rectified at the rectifier circuit  108  and stored in the capacitor  106 . Power obtained by receiving the electromagnetic wave at the antenna  102  is input to the low-frequency signal generation circuit  110  through the rectifier circuit  108 . Further, power obtained by receiving the electromagnetic wave at the antenna  102  is input to the power supply circuit  114  through the rectifier circuit  108  and the switching circuit  112  as a signal. The low-frequency signal generation circuit  110  outputs an on/off control signal to the switching circuit  112  when operation of the low-frequency signal generation circuit  110  is controlled by the input signal. 
         [0073]    In  FIG. 8 , the power obtained by receiving the electromagnetic wave is stored in the capacitor  106 . When the power is not sufficiently supplied from the power feeder  120 , power supplied from the capacitor  106  is supplied to the power supply circuit  114  through the switching circuit  112 . The power feeder  120  is a device for emitting an electromagnetic wave that can be received at the antenna  102 . 
         [0074]    A structure of the antenna  102  in  FIG. 8  may be selected from an electromagnetic coupling method, an electromagnetic induction method, a micro-wave method or the like, depending on a frequency band of the electromagnetic wave that is received. The antenna  102  can arbitrarily receive an electromagnetic wave and supply a signal to the power supply control circuit  104 , regardless of whether or not an electromagnetic wave supplied by the power feeder  120  exists. For example, an electromagnetic wave of a cellular phone (800 to 900 MHz band, 1.5 GHz, 1.9 to 2.1 GHz band, or the like), an electromagnetic wave oscillated from the cellular phone, an electromagnetic wave of a radio wave clock (40 kHz or the like), noise of a household AC power supply (60 Hz or the like), electromagnetic waves that are randomly generated from other wireless signal output means, and the like can be utilized as an electromagnetic wave received at the antenna  102  in order to be stored in the capacitor  106  of the power storage device  100 . 
         [0075]    Next, operation for charging the capacitor  106  and supplying power to the power supply circuit  114  by receiving an electromagnetic wave in the power storage device  100  of  FIG. 8  will be explained. The electromagnetic wave received at the antenna  102  is half-wave rectified and smoothed by the rectifier circuit  108 . Then, the power output from the rectifier circuit  108  is supplied to the power supply circuit  114  through the switching, circuit  112 , and surplus power is stored in the capacitor  106 . 
         [0076]    In the power storage device  100  of this embodiment, by intermittently operating the power storage device  100  depending on strength of the electromagnetic wave, it is attempted that power stored in the capacitor  106  is not consumed wastefully. Although the power storage circuit generally supplies continuous power to a load, continuous power is not always necessary to be supplied depending on use application. In such a case, operation of supplying power from the power storage device  100  is stopped, whereby consumption of the power stored in the capacitor  106  can be suppressed. In this embodiment, only the low-frequency signal generation circuit  110  in  FIG. 8  operates continuously. The low-frequency signal generation circuit  110  operates based on the power stored in the capacitor  106 . An output waveform of the low-frequency signal generation circuit  110  is explained with reference to  FIG. 9 . 
         [0077]      FIG. 9  shows a waveform of a signal that is output from the low-frequency signal generation circuit  110  to the switching circuit. In an example of  FIG. 9 , a duty ratio of the output waveform is set 1:n (n is an integer) so that power consumption can be set approximately 1/(n+1). The switching circuit  112  is driven in accordance with this signal. The switching circuit  112  connects the capacitor  106  and the power supply circuit  114  only during a period where the output signal is high; therefore, power is supplied to a load through the power supply circuit from a battery in the power storage device only during the period. 
         [0078]      FIG. 10  shows an example of the low-frequency signal generation circuit  110  of  FIG. 8 . The low-frequency signal generation circuit  110  in  FIG. 10  includes a ring oscillator  122 , a frequency-divider circuit  124 , an AND circuit  126 , and inverters  128  and  130 . An oscillation signal of the ring oscillator  122  is frequency-divided with the frequency-divider circuit  124  and the output thereof is input into the AND circuit  126  to generate a low-duty ratio signal with the AND circuit  126 . Further, the output of the AND circuit  126  is input to a switching circuit  112  including a transmission gate  132  through the inverters  128  and  130 . The ring oscillator  122  oscillates with a low frequency, and oscillation is performed at 1 kHz, for example. 
         [0079]      FIG. 11  is a timing chart of a signal output from the low-frequency signal generation circuit  110  shown in  FIG. 10 .  FIG. 11  shows an example of an output waveform of the ring oscillator  122 , an output waveform of the frequency-divider circuit  124 , and an output waveform of the AND circuit  126 . In  FIG. 11 , an output waveform is shown, in which a signal output from the ring oscillator  122  is frequency-divided, where the number of division is 1024. As the output waveform, a frequency-divider circuit output waveform  1 , a frequency-divider circuit output waveform  2 , and a frequency-divider circuit output waveform  3  are sequentially output. When these output waveforms are processed with the AND circuit  126 , a signal with a duty ratio of 1:1024 can be formed. As long as the oscillation frequency of the ring oscillator  122  is 1 KHz at this time, an operation period is 0.5 μsec, and a non-operation period is 512 μsec in one cycle. 
         [0080]    The signal output from the low-frequency signal generation circuit  110  regularly controls on/off of the transmission gate  132  of the switching circuit  112  and controls supply of the power from the capacitor  106  to the power supply circuit  114 . Therefore, supply of the power from the power storage device  100  to the load can be controlled. In other words, the power is intermittently supplied from the capacitor  106  to a signal control circuit portion, whereby supply of the power from the power storage device  100  to the load  118  can be suppressed; and low power consumption can be achieved. 
         [0081]    An example of the power supply circuit  114  in  FIG. 8  is explained with reference to  FIG. 12 . The power supply circuit  114  comprises a reference voltage circuit and a buffer amplifier. The reference voltage circuit includes a resistor  134 , and transistors  136  and  138  that are diode-connected. In this circuit, a reference voltage (2×Vgs) corresponding to a voltage between a gate and a source (Vgs) of the transistor is generated by the transistors  136  and  138 . The buffer amplifier includes a differential circuit that includes transistors  140  and  142 , a current mirror circuit that includes transistors  144  and  146 , a current supply resistor  148 , and a common source amplifier that includes a transistor  150  and a resistor  152 . 
         [0082]    The power supply circuit  114  shown in  FIG. 12  operates in such a manner that when a large amount of current is output from an output terminal, the amount of current that flows through the transistor  150  becomes small, whereas when a small amount of current is output from the output terminal, the amount of current that flows through the transistor  150  becomes large. Thus, a current that flows through the resistor  152  is almost constant. In addition, the potential of the output terminal is almost the same as that of the reference voltage circuit. Here, although the power supply circuit including the reference voltage circuit and the buffer amplifier is shown, the power supply circuit  114  is not limited to the structure in  FIG. 12 , and a power supply circuit with a different structure may be used. 
         [0083]    As described above, the power supply control circuit of this embodiment can be applied to the power storage device of Embodiment 1. According to the power supply control circuit of this embodiment, an electromagnetic wave can be received and used as power to be stored in the capacitor. The power stored in the capacitor  106  can be supplied to a load. In addition, supply of the power from the power storage device to the load can be controlled. In other words, the power is intermittently supplied from the capacitor to the signal control circuit portion, whereby supply of the power from the power storage device to the load is suppressed, and power consumption can be reduced. 
       Embodiment 4 
       [0084]    This embodiment will explain an example of a power storage device corresponding to Embodiment 2 with reference to  FIG. 13 . Note that different points from  FIG. 8  will be mainly explained below. 
         [0085]    A structure of a power storage device provided with a plurality of antenna circuits is shown in  FIG. 13 . An antenna  102  and a second antenna  103  are provided as the plurality of antenna circuits, which is different point from  FIG. 8 . The antenna  102  and the second antenna  103  are preferably formed so that compatible reception frequencies are different from each other. For example, the antenna  102  can formed of a spiral antenna as shown in  FIG. 6A  of Embodiment 2, and the second antenna  103  can be formed of a ceramics antenna (patch antenna). 
         [0086]    The antenna  102  is formed in the first structural body  10  in accordance with Embodiment 2. The second antenna  103  corresponds to the ceramics antenna  38 . A capacitor  106  is formed in the second structural body  12 . A power supply control circuit  104  corresponds to the power supply control circuit  14 . 
         [0087]    Electromagnetic waves received at the antenna  102  and the second antenna  103  are rectified at a rectifier circuit  108  and stored in the capacitor  106 . In the rectifier circuit  108 , the electromagnetic waves received at both antennas can be rectified concurrently and stored in the capacitor  106 . Alternatively, one of the electromagnetic waves received at the antenna  102  and the second antenna  103 , which has stronger field intensity than the other, may be preferentially rectified at the rectifier circuit  108  to be stored in the capacitor  106 . 
         [0088]    Another structure of the power storage device  100  in this embodiment is the same as that of  FIG. 8 , and a similar operation effect can be obtained. 
       Embodiment 5 
       [0089]    This embodiment shows a power storage device having a function for controlling supply of power that is stored in a capacitor. Note that the portion having a similar function as that shown in Embodiment 3 is denoted by the same reference numeral to explain this embodiment. 
         [0090]    A power storage device  100  of  FIG. 14  includes an antenna  102 , a power supply control circuit  104 , and a capacitor  106 . The power supply control circuit  104  includes a rectifier circuit  108 , a control circuit  116 , a low-frequency signal generation circuit  110 , a switching circuit  112 , and a power supply circuit  114 . Power is supplied from the power supply circuit  114  to a load  118 . 
         [0091]    The antenna  102  is fowled in the first structural body  10  in accordance with Embodiment 1. The capacitor  106  is fowled in the second structural body  12 . The power supply control circuit  104  corresponds to the power supply control circuit  14 . 
         [0092]    In the power storage device of this embodiment, when power output from the rectifier circuit  108  exceeds power consumption of the load  118 , the power supply control circuit  104  stores the excess power in the capacitor  106 . Alternatively, when power that is output from the rectifier circuit  108  is insufficient for power consumption of the load  118 , the power supply control circuit  104  discharges the capacitor  106  so that power is supplied to the power supply circuit  114 . In  FIG. 14 , a control circuit  116  at the subsequent stage of the rectifier circuit  108  is provided for performing such operation. 
         [0093]    In  FIG. 15 , an example of the control circuit  116  is shown. The control circuit  116  includes switches  154  and  156 , rectifier elements  158  and  160 , and a voltage comparator circuit  162 . In  FIG. 15 , the voltage comparator circuit  162  compares a voltage output from the capacitor  106  with a voltage output from the rectifier circuit  108 . When a voltage output from the rectifier circuit  108  is sufficiently higher than a voltage output from the capacitor  106 , the voltage comparator circuit  162  turns the switch  154  on and turns the switch  156  off. In such a condition, a current flows in the capacitor  106  from the rectifier circuit  108  through the rectifier element  158  and the switch  154 . On the other hand, when a voltage output from the rectifier circuit  108  is insufficient as compared with a voltage output from the capacitor  106 , the voltage comparator circuit  162  turns the switch  154  off and turns the switch  156  on. At this time, when a voltage output from the rectifier circuit  108  is higher than a voltage output from the capacitor  106 , a current does not flow in the rectifier element  160 ; however, when a voltage output from the rectifier circuit  108  is lower than a voltage output from a battery, a current flows in the switch circuit  112  from the capacitor  106  through the switch  156  and the rectifier element  160 . 
         [0094]      FIG. 16  shows a structure of the voltage comparator circuit  162 . In the structure shown in  FIG. 16 , the voltage comparator circuit  162  divides the voltage output from the capacitor  106  with resistor elements  164  and  166 , and divides the voltage output from the rectifier circuit  108  with resistor elements  168  and  170 . Then, the voltage comparator circuit  162  inputs the divided voltage into a comparator  172 . Inverter-type buffer circuits  174  and  176  are connected in series by an output of the comparator  172 . Then, an output of the buffer circuit  174  is input to a control terminal of the switch  154 , and an output, of the buffer circuit  176  is input to a control terminal of the switch  156 , whereby on/off of the switches  154  and  156  is controlled. For example each of the switches  154  and  156  is turned on when an output of the buffer circuit  174  or  176  is at the high potential (“H” level), and each of the switches  154  and  156  is turned off when an output of the buffer circuit  174  or  176  is at the low potential (“L” level). In such a manner, each voltage of the capacitor  106  and the rectifier circuit  108  is divided with the resistor to be input into the comparator  172 , whereby on/off of the switches  154  and  156  can be controlled. 
         [0095]    Note that the control circuit  116  and the voltage comparator circuit  162  are not limited to the above structure, and other types of control circuits and voltage comparator circuits may be used as long as they have various functions. 
         [0096]    Operation of the power storage device  100  shown in  FIG. 14  is generally as follows. First, an external wireless signal received at the antenna  102  is half-waved rectified by the rectifier circuit  108  and then smoothed. Then, a voltage output from the capacitor  106  and a voltage output from the rectifier circuit  108  are compared at the control circuit  116 . When the voltage output from the rectifier circuit  108  is sufficiently higher than the voltage output from the capacitor  106 , the rectifier circuit  108  is connected to the capacitor  106 . At this time, power output from the rectifier circuit  108  is supplied to the capacitor  106  and the power supply circuit  114 , and surplus power is stored in the capacitor  106 . 
         [0097]    The control circuit  116  compares the output voltage of the rectifier circuit  108  with the output voltage of the capacitor  106 . When the output voltage of the rectifier circuit  108  is lower than that of the capacitor  106 , the control circuit  116  controls the capacitor  106  and the power supply circuit  114  to be connected. When the output voltage of the rectifier circuit  108  is higher than that of the capacitor  106 , the control circuit  116  operates so that the output of the rectifier circuit  108  is input to the power supply circuit  114 . In other words, the control circuit  116  controls the direction of current in accordance with the voltage output from the rectifier circuit  108  and the voltage output from the capacitor  106 . 
         [0098]    Moreover, as shown in  FIG. 8  of Embodiment 3, the power is intermittently supplied from the capacitor  106  to the load  118  through the power supply circuit  114 , whereby the amount of power consumption can be reduced. Furthermore, a plurality of antennas may be provided as shown in Embodiment 4. 
         [0099]    In the power storage device of this embodiment, power of an electromagnetic wave received at the antenna and power stored in the capacitor are compared by the control circuit depending on a reception state of an electromagnetic wave, whereby a path of power supplied to the load can be selected. Accordingly, the power stored in the capacitor can be efficiently utilized, and the power can be stably supplied to the load. 
       Embodiment 6 
       [0100]    This embodiment will describe a transistor that can be applied to the power supply control circuit  14  in Embodiments 1 to 5. 
         [0101]      FIG. 17  shows a thin film transistor formed over a substrate  178  having an insulating surface. A glass substrate such as aluminosilicate glass, a quartz substrate, or the like can be employed as the substrate. The thickness of the substrate  178  is 400 μm to 700 μm; however, the substrate may be polished to have a thin thickness of 5 μm to 100 μm. This is because the mechanical strength can be maintained by using the substrate with the second structural body as shown in Embodiments 1 to 3. 
         [0102]    A first insulating layer  180  may be formed using silicon nitride or silicon oxide over the substrate  178 . The first insulating layer  180  has an effect for stabilizing characteristics of the thin film transistor. A semiconductor layer  182  is preferably polycrystalline silicon. Alternatively, the semiconductor layer  182  may be a single crystalline silicon thin film, of which a crystal grain boundary does not affect drift of carriers in a channel formation region overlapping with a gate electrode  186 . 
         [0103]    As another structure, the substrate  178  may be formed using a silicon semiconductor, and the first insulating layer  180  may be found using silicon oxide. In this case, the semiconductor layer  182  can be formed using single crystalline silicon. In other words, a SOI (Silicon on Insulator) substrate can be used. 
         [0104]    The gate electrode  186  is formed over the semiconductor layer  182  with a gate insulating layer  184  interposed therebetween. Sidewalls may be formed on opposite sides of the gate electrode  186 , and a lightly doped drain may be formed in the semiconductor layer  182  by the sidewalls. A second insulating layer  188  is formed using silicon oxide and silicon oxynitiride. The second insulating layer  188  is a so-called interlayer insulating layer, and a first wiring  190  is formed thereover. The first wiring  190  is connected to a source region and a drain region formed in the semiconductor layer  182 . 
         [0105]    A third insulating layer  192  is formed using silicon nitride, silicon oxynitiride, silicon oxide, or the like, and a second wiring  194  is formed. Although the first wiring  190  and the second wiring  194  are shown in  FIG. 17 , the number of wirings to be stacked may be selected as appropriate, depending on the circuit structures. As for a wiring structure, an embedded plug may be formed by selective growth of tungsten in a contact hole, or a copper wiring may be formed by a damascene process. 
         [0106]    A connection electrode  24  is exposed on an outermost surface of the power supply control circuit  14 . The other region than the connection electrode  24  is covered with a fourth insulating layer  196 , for example, so as not to expose the second wiring  194 . The fourth insulating layer  196  is preferably formed using silicon oxide that is formed by coating in order to planarize a surface thereof. The connection electrode  24  is formed by forming a bump of copper or gold by a printing method or a plating method so as to lower contact resistance thereof. 
         [0107]    As described above, an integrated circuit includes a thin film transistor, whereby the power supply control circuit  14  that operates by receiving a communication signal in a microwave band (2.45 GHz) from an RF band (typically, 13.56 MHz) can be formed. 
       Embodiment 7 
       [0108]    This embodiment will describe another structure of the transistor that is applied to the power supply control circuit  14  in Embodiments 1 to 5 shown in  FIG. 18 . Note that a portion having the same function as that of Embodiment 6 is denoted by the same reference numeral. 
         [0109]      FIG. 18  shows a MOS (Metal Oxide Semiconductor) transistor, which is fowled utilizing a semiconductor substrate  198 . A single crystalline silicon substrate is typically employed as the semiconductor substrate  198 . The thickness of the substrate  198  is 100 μm to 300 μm; however, the substrate  198  may be polished to be as thin as 10 μm to 100 μm. This is because the mechanical strength can be maintained when the substrate is used with the second structural body  12  as shown in Embodiments 1 to 3. 
         [0110]    An element isolation-insulating layer  200  is formed over the semiconductor substrate  198 . The element isolation-insulating layer  200  can be formed using a LOCOS (Local Oxidation of Silicon) technique, in which a mask such as a nitride film is formed over the semiconductor substrate  198  and is thermally oxidized to be an oxide film for element isolation. Alternatively, the element isolation-insulating layer  200  may be formed by using a STI (Shallow Trench Isolation) technique in which a groove in the semiconductor substrate  198  is formed and an insulating film is embedded therein and is planarized. When the STI technique is used, the element isolation insulating layer  200  can have a steep side walls, and the distance for element isolation can be reduced. 
         [0111]    An n-well  202  and a p-well  204  are formed in the semiconductor substrate  198 , and accordingly, a so-called double well structure can be formed, in which an n-channel transistor and a p-channel transistor are included. Alternatively, a single-well structure may be used. A gate insulating layer  184 , a gate electrode  186 , a second insulating layer  188 , a first wiring  190 , a third insulating layer  192 , a second wiring  194 , a connection electrode  24 , and a fourth insulating layer  196  are similar to those of Embodiment 6. 
         [0112]    As described above, an integrated circuit includes a MOS transistor, whereby the power supply control circuit  14  can be formed, which operates by receiving a communication signal in a microwave (2.45 GHz) band from an RF band (typically, 13.56 MHz). 
       Embodiment 8 
       [0113]    This embodiment describes an example of a so-called active wireless tag in which an IC (integrated circuit) with a sensor and a power storage device that supplies driving power to the IC with a sensor are provided which is shown in  FIG. 19 . 
         [0114]    This active wireless tag is provided with an IC  206  with a sensor and a power storage device  100 . The power storage device  100  includes an antenna  102 , a power supply control circuit  104 , and a capacitor  106 . 
         [0115]    In the power storage device  100 , an electromagnetic wave received at the antenna  102  generates induced electromotive force at a resonance circuit  107 . The induced electromotive force is stored in the capacitor  106  through a rectifier circuit  108 . When power is supplied to the IC  206  with a sensor, the power is output after an output voltage is stabilized by a constant voltage circuit  109 . 
         [0116]    In the IC  206  with a sensor, a sensor portion  220  has a function for detecting temperature, humidity, illuminance, and other characteristics by a physical or chemical means. The sensor portion  220  includes a sensor  210  and a sensor driving circuit  219  for controlling the sensor  210 . The sensor  210  is formed using a semiconductor element such as a resistor element, a capacitive coupling element, an inductive coupling element, a photovoltaic element, a photoelectric conversion element, a thermoelectric element, a transistor, a thermistor, a diode, or the like. The sensor driving circuit  219  detects changes in impedance, reactance, inductance, a voltage or current; converts signals from analog to digital (A/D conversion); and outputs the signals to a control circuit  214 . 
         [0117]    A memory portion  218  is provided with a read-only memory and a rewritable memory. The memory portion  218  is formed of a static RAM, an EEPROM (Electrically Erasable Programmable Read-Only Memory), a flash memory, or the like, whereby information received through the sensor portion  220  and an antenna  208  can be recorded as needed. In order to memorize the obtained data in the sensor portion  220 , the memory portion  218  preferably includes a nonvolatile memory that is capable of sequentially writing and holding the memorized data. Further, a program for making the sensor portion  220  operate may be memorized in the memory portion  218 . While the program is practiced, the sensor portion  220  can operate at the timing that is set in advance to obtain data without sending a control signal from outside. 
         [0118]    A communication circuit  212  includes a demodulation circuit  211  and a modulation circuit  213 . The demodulation circuit  211  demodulates a signal that is input via the antenna  208  and outputs the signal to the control circuit  214 . The signal includes a signal for controlling the sensor portion  220  and/or information to be memorized in the memory portion  218 . A signal output from the sensor driving circuit  219  and information that is read from the memory portion  218  are output to the modulation circuit  213  via the control circuit  214 . The modulation circuit  213  modulates the signal into a signal capable of wireless communication and outputs the signal to the external device via the antenna  208 . 
         [0119]    Power necessary for operation of the control circuit  214 , the sensor portion  220 , the memory portion  218 , and the communication circuit  212  is supplied from the power storage device  100 . A power supply circuit  216  transforms the power supplied from the power storage device  100  into a predetermined voltage and supplies the voltage to each circuit. For example, in a case where data is written in the above nonvolatile memory, a voltage is temporary boosted to 10V to 20V. Further, a clock signal is generated for making the control circuit operate. 
         [0120]    As described above, by using the power storage device  100  with the IC  206  with a sensor, the sensor portion is effectively utilized, and information can be obtained wirelessly to be memorized. 
         [0121]      FIG. 20  shows an example of distribution management using an active wireless tag  230 . The active wireless tag  230  includes the IC with a sensor and the power storage device shown in  FIG. 19 . This active wireless tag  230  is attached to a packing box  228  containing products  229 . A product management system  222  comprises a computer  224  and a communication device  226  connected to the computer  224 , and the system  222  is used for management of the active wireless tag  230 . The communication devices  226  can be located in each portion where the products are distributed, by using the communication network. 
         [0122]    The distribution management can employ various modes. For example, when a temperature sensor, a humidity sensor, a light sensor, or the like is used as a sensor of the active wireless tag  230 , the environments where the packing box  228  is kept during the distribution process can be managed. In this case, the power storage device is provided for the active wireless tag  230 ; therefore, the sensor can operate at a given timing independently from a control signal from the communication device  226 , and the environment data can be obtained. Furthermore, even when the distance between the communication device  226  and the active wireless tag  230  is large, the communication distance can be increased with the use of power of the power storage device. 
         [0123]    As described, the active wireless tag provided with the IC with a sensor and the power storage device is used, whereby a variety of information is obtained wirelessly with sensors, and the information can be managed by the computer. 
       ADDITIONAL NOTE 
       [0124]    As described above, the present invention includes at least the following structure. 
         [0125]    An aspect of the present invention is a power storage device including a first structural body provided with an antenna, a power supply control circuit formed using a semiconductor layer interposed between insulating layers that are provided over and below the semiconductor layer, and a second structural body provided with a capacitor and having higher rigidity than the first structural body, where the antenna and the power supply control circuit are connected with a through electrode formed in the second structural body, the power supply control circuit includes a rectifier circuit, a switching circuit, a low-frequency signal generation circuit, and a power supply circuit, and the switching circuit controls power that is supplied from the capacitor or the antenna to the power supply circuit in accordance with a signal from the low-frequency signal generation circuit. 
         [0126]    Another aspect of the present invention is a power storage device including a first structural body provided with an antenna, a power supply control circuit formed using a semiconductor layer interposed between insulating layers that are provided over and below the semiconductor layer, and a second structural body provided with a capacitor and having higher rigidity than the first structural body, where the antenna and the power supply control circuit are connected with a through electrode formed in the second structural body, the power supply control circuit includes a rectifier circuit, a control circuit, a switching circuit, a low-frequency signal generation circuit, and a power supply circuit, the control circuit selects power that is output to the switching circuit by comparing power supplied from the antenna with power supplied from the capacitor, and the switching circuit outputs the power selected by the control circuit to the power supply circuit in accordance with a signal from the low-frequency signal generation circuit. 
         [0127]    Another aspect of the present invention is a power storage device including a first structural body provided with an antenna, a power supply control circuit formed using a semiconductor layer interposed between insulating layers that are provided over and below the semiconductor layer, and a second structural body provided with a capacitor and having higher rigidity than the first structural body, where the power supply control circuit has a connection portion of the antenna and the capacitor, which is interposed between the first structural body and the second structural body, the power supply control circuit includes a rectifier circuit, a switching circuit, a low-frequency signal generation circuit, and a power supply circuit, and the switching circuit controls power that is supplied from the capacitor or the antenna to the power supply circuit in accordance with a signal from the low-frequency signal generation circuit. 
         [0128]    Another aspect of the present invention is a power storage device including a first structural body provided with an antenna, a power supply control circuit formed using a semiconductor layer interposed between insulating layers that are provided over and below the semiconductor layer, and a second structural body provided with a capacitor and has higher rigidity than the first structural body, where the power supply control circuit having a connection portion of the antenna and the capacitor, which is interposed between the first structural body and the second structural body, the power supply control circuit includes a rectifier circuit, a control circuit, a switching circuit, a low-frequency signal generation circuit, and a power supply circuit, the control circuit selects power that is output to the switching circuit by comparing power supplied from the antenna with power supplied from the capacitor, and the switching circuit controls an output of power to the power supply circuit, which is selected by the control circuit in accordance with a signal from the low-frequency signal generation circuit. 
         [0129]    This application is based on Japanese Patent Application serial no. 2006-206939 filed in Japan Patent Office on Jul. 28, 2006, the entire contents of which are hereby incorporated by reference.

Technology Classification (CPC): 7