JP2007212466A - System for measuring flow line - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system for measuring a flow line for following the positions of a moving detection target while making it easy to analyze a history of movements of each detection target and enhancing confidentiality of information. <P>SOLUTION: A transmitting apparatus 1 is fixed in a predetermined position, and includes: a compressional wave transmitting section 11 for intermittently transmitting compressional waves; and an identification data transmitting section 12 for transmitting identification data by wireless signals that are transmitted via infrared. A receiving apparatus 2 is mounted in a detection target, such as a moving object, whose positions are to be detected, and stores its positions in a memory section 26 by receiving the compressional waves. The receiving apparatus 2 includes: a unique information input section 28 for inputting unique information that specifies the detection target; a memory section 27 for memorizing a history of positions of the transmitting apparatus 1 and the unique information sent from the unique information input section 28, the positions of the transmitting apparatus 1 being calculated by a control section 20; and an interface 26 for retrieving, via a non-wireless transmission path, memory content stored in the memory section 27. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a flow line measurement system that tracks the position of a detection target using an ultrasonic wave that periodically repeats a pressure change of a medium or a so-called pressure wave in which the pressure change of the medium is single. It is.

  2. Description of the Related Art Conventionally, a technique for adding a function of detecting a current position to a shopping cart and providing information such as a product according to the position of the shopping cart is known (for example, see Patent Document 1). The shopping cart described in Patent Document 1 detects the position of the shopping cart by using a distance sensor, a direction sensor, and a height sensor. Therefore, in order to match the initial position, position information is provided at a specified start position. Need to be reset.

In addition, as a technique for providing information such as a product according to the position of the shopping cart, an IC tag is provided in the shopping cart, and the identification information of the IC tag is read by a reader provided on the display stand of the product. It is also considered to detect the approach of a cart (for example, see Patent Document 2).
JP-A-6-107183 JP 2005-108180 A

  By the way, in the technique described in Patent Document 1, it is necessary to reset the position information by aligning the shopping cart with the start position every time the shopping cart is used. In addition, since only the position of the shopping cart is detected and product information is presented, it is impossible to analyze what kind of product is purchased and what type of product is interested.

  The technique described in Patent Document 2 does not require the trouble of resetting the position information by aligning the shopping cart with the start position, but only detects that the shopping cart is close to the product. It is somewhat difficult to analyze the history of In addition, similar to the one described in Patent Document 1, since only the product information is presented when the shopping cart approaches the product, what customers purchase what products and what products are interested. You cannot analyze what you have.

  In Patent Document 2, identification information for identifying each shopping cart is stored in the IC tag. However, the shopping cart is used by an unspecified number of people, and the identification stored in the IC tag is used. Since the information is fixedly set in each shopping cart, it cannot be used as information for identifying a customer who uses the shopping cart, and eventually the customer and the product cannot be linked. Moreover, since identification information is exchanged using a wireless transmission path, the identification information may be intercepted and used by a third party, which is not suitable for transmission of information including customer personal information. is there.

  The present invention has been made in view of the above reasons, and its purpose is to temporarily store the history of the position of the detection target and the specific information of the detection target in the storage unit when tracking the position where the detection target has moved. By taking it out through a non-wireless transmission path later, it becomes easier to analyze the movement history of the detection target, improve the confidentiality of the information, and provide a specific information input unit for inputting the specific information. It is an object of the present invention to provide a flow line measurement system in which specific information can be input any time and the history of the position for each detection target can be analyzed.

  According to the first aspect of the present invention, there is provided a transmission device that is fixed at a fixed position and intermittently transmits a sparse / dense wave, and a transmission device that is mounted on a position detection target and receives a sparse / dense wave transmitted from the transmission device. A receiving device that detects the relative position of the signal, and a management device that tracks the position to which the detection target has moved based on the position history obtained by the receiving device, and the transmitting device transmits the dense wave. The receiving device is an array in which a plurality of wave receiving elements that receive the dense wave transmitted from the dense wave transmitting unit and convert the received dense wave into a received signal that is an electric signal are arranged. Based on the time difference between the reception times of the dense waves by the receiving elements of the sensor and the receiving elements of the dense wave receiving section and the arrangement positions of the receiving elements, the density of the dense waves receiving section A position calculation unit for determining the direction of arrival and the distance to the transmission device; A storage unit for storing a unique information input unit for inputting unique information for specifying a detection target on which the receiving device is mounted, a history of relative positions of the transmission device obtained by the position calculation unit, and unique information input from the unique information input unit And an interface for retrieving the stored contents stored in the storage unit through a non-wireless transmission path.

  According to this configuration, since the unique information of the detection target and the history of the position are associated with each other and stored in the storage unit, the path along which the detection target has moved can be analyzed for each detection target. Moreover, since the unique information can be input from the unique information input unit, it is possible to input the unique information according to the detection target at any time, for example, a member used by an unspecified number of people such as a shopping cart, It is possible to give unique information for each individual to be used. Furthermore, since the storage content of the storage unit is extracted through a non-wireless transmission path, the confidentiality of the unique information is higher than when a wireless transmission path is used.

  According to a second aspect of the present invention, in the first aspect of the invention, the transmitting device includes an identification data transmitting unit that transmits unique identification data using a wireless signal, and the receiving device is identified from the identification data transmitting unit. An identification data receiving unit for receiving data is provided, wherein the position calculation unit obtains a distance from the transmission device based on a relationship between a reception time of the sparse / dense wave and a reception time of the identification data.

  According to this configuration, since the reception device receives the identification data unique to the transmission device, the relative position with the transmission device can be obtained without interference even when there are a plurality of transmission devices. In addition, the position calculation unit can know the propagation time of the dense wave from the transmission device to the reception device using the relationship between the reception time of the identification data and the reception time of the dense wave, and transmission can be performed by using this propagation time. You can know the distance to the device.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the receiving device includes a clock unit that counts time, and the clock unit counts time when the relative position of the transmission device is stored in the storage unit. It is characterized by being stored in association with the current time.

  According to this configuration, since the position where the detection target has moved is associated with the time, the change in the movement speed of the detection target can be analyzed, and the location where the detection target stopped and the average of the detection target moved It becomes possible to find the speed.

  According to a fourth aspect of the present invention, in the third aspect of the present invention, the interface has a function of transferring the stored contents of the storage unit to an external device and receiving time information from the external device, and the clock unit is an external device It has a function of correcting the time using clock information from.

  According to this configuration, since the time measured by the clock unit is automatically adjusted to the time managed by the external device, the time accuracy is improved and the external device manages a plurality of receiving devices. It becomes possible to make the time of each receiving device substantially coincide.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the interface includes a human body that touches an electrode between an electrode that can be contacted by the human body and a reader / writer attached to the human body. And a data communication device that enables data communication used in a part of the transmission path. The reader / writer has a function of storing received data and a function of transmitting stored data.

  According to this configuration, since the human body is used as part of the transmission path and the reader / writer attached to the human body is interposed, data can be transferred between the receiving device and the external device. Such cable connection is unnecessary, and it is possible to prevent data leakage and improve confidentiality as compared with wireless data communication.

  According to the configuration of the present invention, since the unique information of the detection target and the history of the position are stored in the storage unit, there is an advantage that the path along which the detection target has moved can be analyzed for each detection target. In addition, since the unique information can be input from the unique information input unit, the unique information corresponding to the detection target can be input at any time, for example, a member used by an unspecified number of people such as a shopping cart, It is possible to give unique information for each individual to be used. Furthermore, the path traveled by the detection target is stored in the storage unit as stored content, and the stored content in the storage unit is taken out through the interface, and the stored content in the storage unit is taken out through a non-wireless transmission path, so wireless transmission Compared to the case where a road is used, there is an advantage that the possibility of information leakage can be reduced and the confidentiality of unique information is increased.

(Embodiment 1)
In the present embodiment, as shown in FIG. 2, a moving body (for example, a shopping cart) that moves on the floor surface FL in a building is set as a detection target Ob for position detection, and a movement for tracking the position where the detection target Ob has moved is tracked. A line measurement system is illustrated. In order to track the position of the detection target Ob, a transmission device 1 that transmits a sparse / dense wave is installed at a fixed position of the ceiling surface CL above the floor surface FL, and the detection target Ob receives a sparse / dense wave. The receiving device 2 is mounted. Therefore, the transmission device 1 is arranged at a known position. In this embodiment, although the example which installs the transmitter 1 in the ceiling surface CL is shown, you may install in a wall surface. In addition, the relative position of the transmission device 1 is measured in the reception device 2, and the coordinate position of the reception device 2 is obtained from the known coordinate position related to the transmission device 1 and the measured relative position. In the present embodiment, a pressure wave in which a pressure change of the medium (air) occurs once as a dense wave is used.

  As shown in FIG. 1, the transmission device 1 includes a dense wave transmission unit 11 that transmits a dense wave, and an identification data transmission unit 12 that transmits a wireless signal using infrared as a transmission medium. The sparse / dense wave transmission unit 11 and the identification data transmission unit 12 operate in response to instructions from the control unit 10 via the drivers 13 and 14, respectively. The control unit 10 includes a one-chip microcomputer and includes a CPU, RAM, ROM, and serial communication interface. The sparse / dense wave transmission unit 11 intermittently transmits the sparse / dense wave, and the identification data transmission unit 12 transmits a wireless signal including identification data. The identification data is set in the control unit 10, and unique identification data is set for each transmission device 1. The control unit 10 controls the transmission timing of the sparse / dense wave and the transmission timing of the wireless signal. Specifically, a sparse wave is transmitted simultaneously with the transmission of a wireless signal including identification data (actually, the one-chip microcomputer is between the time when the wireless signal is transmitted and the time when the sparse wave is transmitted. In other words, the wireless signal and the sparse / dense wave are intermittently output at a predetermined output interval. The functions of the transmission device 1 described above are realized by mounting an appropriate program on the one-chip microcomputer constituting the control unit 10.

  The receiver 2 includes a sparse wave receiver 21 that receives the sparse wave transmitted from the sparse wave transmitter 11 provided in the transmitter 1, and the sparse wave receiver 21 receives the sparse wave. A received signal that is an electrical signal is output. That is, the dense wave receiving unit 21 converts the dense wave into a received signal. The receiving device 2 is also provided with an identification data receiving unit 22 that receives a wireless signal transmitted from the identification data transmitting unit 12 provided in the transmitting device 1. The identification data receiving unit 22 removes the carrier from the wireless signal and extracts the identification data. The identification data composed of the pulse train extracted by the identification data receiving unit 22 is input to the control unit 20, and the transmission device 1 that has transmitted the identification data is recognized by the control unit 20. The control unit 20 includes a microcomputer as a main component, and includes a CPU, a RAM, a ROM, and a serial communication interface.

  Further, an interface 26 capable of input / output is added to the control unit 20. As the interface 26, a serial interface with specifications such as TIA / EIA-232-E and USB, a parallel interface with specifications such as SCSI, and the like can be adopted, and a management device such as a computer server (external device) ( (Not shown), the detection result of the receiving device 2 can be used. The interface 26 does not necessarily require a cable, but employs a configuration that does not use a wireless transmission path.

  The dense wave receiving unit 21 is an array sensor in which a plurality of receiving elements are arranged, and the control unit 20 is based on the time difference between the receiving times of the dense waves by the receiving elements and the arrangement positions of the receiving elements. Thus, the arrival direction of the dense wave, that is, the direction in which the detection object Ob exists is obtained. The direction to be obtained here is a relative direction with respect to the dense wave receiving unit 21, but since the arrangement of the transmission device 1 is known, the arrival direction of the dense wave in absolute coordinates specifying the arrangement of the transmission device 1 is obtained. Can do.

  As described above, in order to obtain the arrival direction of the dense wave, information including the time difference between the reception times at the wave receiving elements that have received the dense wave is required. The wave signal is converted into received data that is a digital signal by the A / D converter 23 and then stored in the data storage unit 24 that temporarily stores the output corresponding to each receiving element. The sparse / dense wave receiving unit 21 always receives incoming sparse / dense waves, but the timing control unit 25 controls the operation timing of the A / D conversion unit 23 and the data storage unit 24 according to instructions from the control unit 20. . The timing control unit 25 is configured using CPLD (Complex Programmable Logic Device) or FPGA (Field Programmable Gate Array), and generates an enable signal for controlling the operation timing of the A / D conversion unit 23 and the data storage unit 24. In addition, an address for designating a storage area of the data storage unit 24 is generated.

  In the control unit 20, when the identification data input from the identification data receiving unit 22 through the serial communication interface is identification data within a pre-registered range, the control unit 20 instructs the timing control unit 25 to receive the reception signal corresponding to the received signal. The standby state for storing the wave data in the data storage unit 24 is entered. This standby state is limited to a wave reception time set after receiving a wireless signal including identification data. In other words, the dense wave received by the dense wave receiving unit 21 outside the reception possible time is not converted into received data and is not stored in the data storage unit 24. In other words, a sparse / dense wave is received only within the reception time.

  The wave reception time is a fixed time, and when the dense wave receiving unit 21 receives the dense wave within the wave reception possible time after the wave reception possible time is started, each wave receiving element receives the density wave. The received data corresponding to the received signal is stored in the data storage unit 24 in a form including the time information. In addition, when the wave reception possible time ends, the dense wave received thereafter becomes invalid.

  The received data stored in the data storage unit 24 is read into the control unit 20 after the reception-enabled time has ended, and adjacent reception signals are obtained in order to obtain a time corresponding to the time difference between reception times at each reception element. The received data corresponding to the element is shifted by a predetermined time in the time axis direction and added.

This process will be briefly described. Now, it is assumed that the receiving elements 40 are arranged one-dimensionally at equal intervals on the same plane as shown in FIG. 3 (in practice, they are arranged two-dimensionally). ). When the angle of the wavefront of the ultrasonic wave with respect to the surface on which the wave receiving elements 40 are arranged is θ ₀ , the arrival direction of the dense wave is also θ ₀ . If the speed of sound is c and the arrangement pitch (intermediate distance) of the receiving elements 40 is L, the time difference ΔT ₀ when the wavefront of the dense wave whose arrival direction is θ ₀ reaches the adjacent receiving element 40 is , ΔT ₀ = L · sin θ ₀ / c. That is, θ ₀ = sin ⁻¹ (ΔT ₀ · c / L), and the arrival direction θ ₀ can be obtained by obtaining the time difference ΔT ₀ .

Based on the above relationship, if the received signal corresponding to the sparse / dense wave received by each receiving element 40 is delayed by the time difference ΔT ₀ corresponding to the arrival direction θ ₀ , the position of the received signal matches in the time axis direction. You can see that For example, the received signals as shown in FIGS. 4A to 4C are output from three adjacent receiving elements 40, and the received signals output from the adjacent receiving elements 40 have a time difference ΔT ₀ . Suppose you are. In this case, the reception signals obtained from the adjacent reception elements 40 are delayed by ΔT _{0 from} each other by appropriate delay means. That is, when the received signal in FIG. 4C is delayed by 2ΔT ₀ and the received signal in FIG. 4B is delayed by ΔT ₀ , both received signals in FIG. It matches the position of the received signal. If the received signals that are the outputs of the receiving elements 40 have the same position in the time axis direction, when these received signals are added, the addition result has a large amplitude. In other words, if the amplitude of the addition result is large, it can be said that the arrival direction θ ₀ of the density wave corresponds to the delay time ΔT ₀ .

In the present embodiment, the received signal is not shifted in the time axis direction, but the received data is shifted in the time axis direction. However, for the purpose of calculating the arrival direction θ ₀ , the difference is Absent. Therefore, the control unit 20 adds the delay time to the received data stored in the data storage unit 24 after applying a plurality of preset delay times and delays the addition result. Ask for time. Since this delay time corresponds to the time difference ΔT ₀ , the arrival direction of the dense wave can be immediately obtained by associating the arrival direction θ ₀ with the delay time in advance. The delay time is set so that, for example, the arrival direction can be detected in increments of 5 degrees. As described above, the process of adding the received data after shifting the received data in the time axis direction is called a delay addition process. The delay addition process is realized by a program set in the control unit 20.

  As described above, when the receiving device 2 receives the wireless signal from the transmitting device 1 and confirms that the wireless signal includes identification data within the range registered in the control unit 20, the reception time limit is limited. The received signal is waited for in the receiver, and the arrival direction of the sparse / dense wave is calculated using only the sparse / dense wave received within the reception time.

  Here, as described above, there is a known fixed time delay between the transmission of the wireless signal and the reception of the sparse / dense wave, but the transmission of the wireless signal from the identification data transmitting unit 12 and the identification data receiving unit 22 Therefore, the time difference between the reception time of the wireless signal at the identification data receiving unit 22 and the reception time of the dense wave at the dense wave receiving unit 21 is known. If the calculation is performed in consideration of the time delay, it can be regarded as a time during which the dense wave propagates through the medium. Therefore, the control unit 20 obtains the relative distance of the transmission device 1 with respect to the reception device 2 based on the time from reception of the wireless signal to reception of the dense wave. That is, since the direction and distance of the transmission device 1 can be known, the reception device 2 can obtain the three-dimensional position of the transmission device 1. The operation of the control unit 20 described above is realized by installing an appropriate program in the microcomputer. Since the control unit 20 obtains the three-dimensional position of the transmission device 1, the control unit 20 functions as a position calculation unit.

  By the way, the management device described above is provided separately from the detection target Ob. For example, if the detection target Ob is a shopping cart, it can be used together with the management device to configure a flow line measurement system that tracks the position where the shopping cart has moved. In this case, the position history obtained by the control unit 20 is stored in the storage unit 27, and the stored contents of the storage unit 27 are transferred to the management device connected via the interface 26. The storage unit 27 uses a flash memory or a hard disk.

  The storage unit 27 also stores unique information set in the receiving device 2. The unique information is information for specifying the receiving device 2, the detection target Ob, the user of the detection target Ob, and the like. For example, when the detection target Ob is a shopping cart, the individual information of the shopping cart and the use of the shopping cart are used. Personal information for identifying the person may be used. The personal information does not necessarily have to identify an individual, and may be information about age and gender, for example. By registering age and gender as unique information in the storage unit 27 together with the history of position, it becomes possible to sort out the trends of products that are of interest by age and gender by the management device, and some kind of marketing research Is possible.

  The unique information is input from the unique information input unit 28. The unique information input unit 28 may use a keyboard, but if a card reader that reads a magnetic card or an IC card is used, information such as a shopping card can be read and solid information can be taken in.

  In the present embodiment, the receiving device 2 is provided with an information presentation unit 29 using at least one of a display and a speaker, and appropriate presentation information is stored in the storage unit 27 with respect to the solid information read from the solid information input unit 28. If stored, the information is presented to the user through the information presentation unit 29.

  For example, when a shopping card is read by a card reader attached to a shopping cart, product information corresponding to specific information registered in the shopping card (information such as recommended products or new products that may be interested) is stored in the storage unit 27. And is presented by the information presentation unit 29. The presentation of product information by the information presentation unit 29 may be linked to the position detected by the control unit 20. For example, when it is determined by the position detected by the control unit 20 that the receiving device 2 has approached the product shelf displaying the product related to the product information to be presented (a predetermined range centered on the position of the product shelf is set in advance) When it is detected that the product is within the range, the product information related to the product on the display shelf is presented to the information presentation unit 29. Such information presentation makes it possible to present highly satisfying information to customers. Information to be presented to the information presentation unit 29 may be fetched from the management device into the storage unit 27 in advance.

  By the way, although the ultrasonic transducer which consists of a piezoelectric element may be used for the transmission element which comprises the dense wave transmission part 11 in the transmitter 1, a piezoelectric element generally has a sharpness (Q value). Since it exceeds 100, the reverberation time is relatively long, and considering the reverberation time, the time interval for transmitting the dense wave becomes long. That is, when the detection target on which the transmission device 1 is mounted is a moving body, the position of the moving body cannot be measured finely.

  Therefore, it is desirable to use the transmission element 30 having a short reverberation time having the structure shown in FIG. In this transmission element 30, a heat insulating layer 32 made of a porous silicon layer is formed on one surface (upper surface in FIG. 5) of a support substrate 31 made of a single crystal p-type silicon substrate. A heating element layer 33 made of a metal thin film (for example, a tungsten thin film) is formed, and a pair of electrode pads 34 electrically connected to the heating element layer 33 is formed on the one surface side of the support substrate 31. Yes. The planar shape of the support substrate 31 is rectangular, and the planar shape of the heat insulating layer 32 and the heating element layer 33 is also rectangular.

  The wave transmitting element 30 is of a thermal excitation type, and the heating element layer 33 is energized so that a temperature change occurs in the heating element layer 33 and the medium in contact with the heating element layer 33 is encouraged to expand and contract. Generate a wave. That is, by energizing between the electrode pads 34 at both ends of the heating element layer 33 to cause a temperature change in the heating element layer 33, a temperature change is caused in the air that is in contact with the heating element layer 33. The air in contact with the heating element layer 33 expands when the temperature of the heating element layer 33 rises and contracts when the temperature of the heating element layer 33 decreases. It is possible to generate a dense wave.

  Since a wave transmitting element made of a piezoelectric element has a high sharpness (Q value), even if a sparse wave is generated instantaneously, even after the driving of the piezoelectric element is stopped, as shown in FIG. Thus, reverberation continues due to resonance. On the other hand, the thermally excited wave transmitting element 30 shown in FIG. 5 has a small sharpness and substantially does not have a resonance frequency. In the thermal excitation type wave transmitting element 30, as described above, a sparse wave is generated in accordance with a temperature change of the heating element layer 33 accompanying energization to the heating element layer 33 via the pair of electrode pads 34.

  That is, when the waveform of the drive voltage or drive current applied to the heating element layer 33 has a sine wave shape, a dense wave having a frequency twice that of the sine waveform can be generated. Therefore, if the waveform of the drive voltage applied to the electrode pad 34 is an isolated wave corresponding to a half cycle of a sine wave, a dense wave corresponding to one cycle of the sine waveform as shown in FIG. 6A is generated. Can do. In addition, the reverberation time is very short because the thermal excitation type transmitting element 30 does not substantially have a resonance frequency. In addition, since the piezoelectric element has a specific resonance frequency, the frequency range of the density wave that can be generated is narrow. However, since the thermal excitation type transmission element 30 does not substantially have the resonance frequency, the frequency range of the density wave that can be generated. Becomes widespread. In addition, if the waveform of the drive voltage or drive current is an isolated wave, a sparse / dense wave of about one cycle can be generated as shown in FIG.

  The above-described thermally excited wave transmitting element 30 uses a p-type silicon substrate as the support substrate 31, and the thermal insulating layer 32 is a porous silicon layer having a porosity of 60 to 80% (preferably about 70%). It is constituted by. This is because if the porosity is less than 60%, the heat insulating effect is reduced, and if the porosity exceeds 80%, the structure becomes brittle. The thermal insulating layer 32 can be formed by anodizing a part of a silicon substrate used as the support substrate 31 in an electrolytic solution made of a mixed solution of hydrogen fluoride aqueous solution and ethanol. Here, by appropriately setting conditions for anodizing treatment (for example, current density, energization time, etc.), the porosity and thickness of the porous silicon layer to be the heat insulating layer 32 can be set to desired values, respectively. .

It is known that the porous silicon layer has a lower thermal conductivity and heat capacity as the porosity increases. For example, a single crystal silicon substrate having a thermal conductivity of 148 W / (m · K) and a heat capacity of 1.63 × 106 J / (m ³ · K) is anodized to form a porous silicon layer having a porosity of 60%. When formed, this porous silicon layer has a thermal conductivity of 1 W / (m · K) and a heat capacity of 0.7 × 10 6 J / (m ³ · K). In the present embodiment, as described above, the heat insulating layer 32 is formed of a porous silicon layer having a porosity of approximately 70%, and the heat conductivity of the heat insulating layer 32 is 0.12 W / (m · K), The heat capacity is 0.5 × 10 6 J / (m ³ · K).

  The thermal insulation layer 32 is made smaller than the support substrate 31 in terms of thermal conductivity and heat capacity, and the product of thermal conductivity and thermal capacity is also made sufficiently smaller than the support substrate 31 in terms of the product of thermal conductivity and thermal capacity. The temperature change of the heat generating body layer 33 can be efficiently transmitted to the air, and heat can be efficiently exchanged between the heat generating body layer 33 and the air. In addition, since the support substrate 31 efficiently receives the heat from the heat insulating layer 32, the heat of the heat insulating layer 32 can be released and the heat from the heating element layer 33 is prevented from being accumulated in the heat insulating layer 32. Can do.

The heating element layer 33 is made of tungsten, which is a kind of refractory metal, and has a thermal conductivity of 174 W / (m · K) and a heat capacity of 2.5 × 10 6 J / (m ³ · K). . The material of the heating element layer 33 is not limited to tungsten, and for example, tantalum, molybdenum, iridium, or the like may be employed.

  In the thermal excitation type wave transmitting element 30 described above, the thickness of the support substrate 31 is 525 μm, the thickness of the thermal insulating layer 32 is 10 μm, the thickness of the heating element layer 33 is 50 nm, and the thickness of each electrode pad 34 is 0. .5 μm. However, these thicknesses are only examples, and are not intended to be particularly limited. Further, Si is adopted as the material of the support substrate 31, but the material of the support substrate 31 is not limited to Si, and for example, it can be made porous by anodizing treatment of Ge, SiC, GaP, GaAs, InP or the like. Other semiconductor materials may be used.

  By the way, the wave receiving element 40 used for the dense wave receiving unit 21 of the receiving device 2 receives the dense wave and converts the received dense wave into a received signal that is an electric signal. The wave section 21 is configured by arranging a plurality of receiving elements 40 on a single substrate (not shown). Here, it is assumed that an array sensor in which the wave receiving elements 40 are two-dimensionally arranged is configured. In the array sensor, the center-to-center distance (arrangement pitch) of the wave receiving elements 40 is set to about the wavelength of the density wave generated from the density wave transmission unit 11 (for example, about 0.5 to 5 times the wavelength of the density wave). It is desirable. This is because if the wavelength is smaller than 0.5 times the wavelength of the dense wave, the time difference between the times when the wave front of the dense wave reaches each of the adjacent receiving elements 40 becomes small, making it difficult to detect the time difference. Although a piezoelectric element can be used as the wave receiving element 40, a configuration with less reverberation is desirable as in the case of the dense wave transmission unit 11. Therefore, it is desirable to use a capacitive wave receiving element 40 that converts the pressure (sound pressure) of the density wave into a change in capacitance.

  This type of receiving element 40 has a configuration shown in FIG. A wave receiving element 40 shown in the figure is formed by a micromachining technique and has a rectangular frame-shaped frame 41 formed by providing a silicon substrate with a window hole 41a penetrating in the thickness direction, and a window hole on one surface side of the frame 41. And a cantilever type pressure receiving plate 42 which is fixed to one of the four sides surrounding 41a and is arranged to cover the window hole 41a. A silicon oxide film 46 is laminated on the one surface of the frame 41 via a thermal oxide film 45, and the surface of the silicon oxide film 46 is covered with a silicon nitride film 47. One end of the pressure receiving plate 42 is fixed to the frame 41 via the thermal oxide film 45, and the other end of the pressure receiving plate 42 faces the silicon oxide film 46 in the thickness direction of the silicon substrate. A fixed electrode 43a made of a metal thin film (for example, a chromium film) is formed on a surface of the silicon oxide film 46 facing the other end of the pressure receiving plate 42, and the other end of the pressure receiving plate 42 faces the fixed electrode 43a. A movable electrode 43b made of a metal thin film (for example, a chromium film) is formed on the back side of the surface facing the fixed electrode 43a. A silicon nitride film 48 is formed on the other surface of the frame 41. Here, the pressure receiving plate 42 is formed of a silicon nitride film formed in a separate process from the silicon nitride films 47 and 48.

  In the capacitive wave receiving element 40 shown in FIG. 7, when the pressure (sound pressure) of the dense wave acts on the pressure receiving plate 42, the distance between the fixed electrode 43a and the movable electrode 43b changes according to the pressure of the dense wave. Therefore, the pressure of the dense wave can be detected by detecting the capacitance between the fixed electrode 43a and the movable electrode 43b. Therefore, if a DC bias voltage is applied between the fixed electrode 43a and the movable electrode 43b, a voltage change corresponding to the pressure of the dense wave occurs between the fixed electrode 43a and the movable electrode 43b. Sound pressure can be converted into an electrical signal. Since this type of capacitive wave receiving element 40 has a sharpness smaller than that of the piezoelectric element, it is possible to widen the frequency bandwidth of the dense wave that can be received compared to the case where the piezoelectric element is used.

  The wave receiving element 40 is not limited to the structure shown in FIG. 7. For example, a movable electrode formed by processing a silicon substrate or the like by a micromachining technique or the like and including a diaphragm portion that receives the pressure of the dense wave, and a diaphragm You may employ | adopt the structure which detects the electrostatic capacitance between the fixed electrodes which consist of a backplate part which opposes a part. In this configuration, a spacer portion made of an insulating film that defines the gap length between the diaphragm portion and the back plate portion when the pressure of the dense wave is not applied is provided, and a plurality of exhaust holes are provided in the back plate portion. To do.

  The sharpness (Q value) of the thermal excitation type transmitting element 30 shown in FIG. 5 is about 1, and the sharpness of the capacitive type receiving element 40 shown in FIG. However, the sharpness is significantly smaller than that of the piezoelectric element. Therefore, as compared with the case where piezoelectric elements are used for the transmitting and receiving elements, the ratio of the reverberation component included in the dense wave transmitted from the dense wave transmitting unit 11 is reduced, and the density of the dense wave receiving unit 21 is reduced. The ratio of the reverberation component contained in the output received signal is reduced. In other words, the transmission interval of the sparse / dense wave can be shortened during transmission, and the received signal corresponding to the sparse / dense wave can be separated so as not to overlap even when the sparse / dense wave is received at a short time interval during reception. it can. Note that the sharpness (Q value) of each of the transmitting element 30 and the receiving element 40 is preferably 10 or less, and more preferably 5 or less.

(Embodiment 2)
As shown in FIG. 8, the present embodiment is provided with a clock unit 16 for measuring time in addition to the configuration of the first embodiment. The clock unit 16 includes a real-time clock IC, and measures the time based on the set time. The time counted by the clock unit 16 is registered in the storage unit 27 in association with the position detected by the control unit 20. That is, each time the position detected by the control unit 20 is updated, the storage unit 27 stores the position and time.

  As described above, by associating the position and time of the receiving device 2 with each other and storing them in the storage unit 27, the management device stores the time at which the reception device 2 has stopped at a specific position or the specific time from the stored contents of the storage unit 27. It becomes possible to know the movement speed between places. Therefore, when the detection target Ob is a shopping cart, it is possible to acquire information such as which product was stopped near, or which product was fast when approaching, and is associated with unique information. It can be used as information for analyzing the preferences of the customers.

  Note that it is desirable that the time adjustment of the clock unit 16 is performed by the management device. That is, it is desirable that the clock unit 16 has a function of correcting the time when the time information is given, and the management device is provided with a function of giving the time information to the clock unit 16 through the interface 26. The interface 26 has a function of receiving clock information from the management device when the storage contents of the storage unit 27 are read by the management device. The control unit 20 receives the clock information received through the interface 26 in the clock unit 16. By giving, the time of the clock unit 16 is corrected. By adopting this configuration, the time of the clock unit 16 is automatically corrected when the storage content of the storage unit 26 is read out by the management device. It can be made to almost coincide with the time. That is, when a plurality of receiving apparatuses 2 are managed by one management apparatus, the time counted by the clock unit 16 in each receiving apparatus 2 can be made substantially coincident. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 3)
In the present embodiment, the interface 26 of the receiving apparatus 2 is connected to a pair of electrodes 17a and 17b as shown in FIG. And a data communication device (not shown) that enables data communication using the human body M as a transmission path through the electrodes 17a and 17b.

  A reader / writer 50 is attached to the human body M, and the human body M is used as a part of a transmission path between the electrodes 51 a and 51 b provided on the reader / writer 50 and the electrodes 17 a and 17 b of the receiving device 2. The illustrated reader / writer 50 is attached to one arm of the human body M. Therefore, the reader / writer 50 is provided with a wearing tool such as a wristband for wearing on the arm. The electrodes 51a and 51b provided on the reader / writer 50 are both in contact with the human body M. In the configuration shown in the drawing, both the electrodes 51a and 51b are spaced apart in the longitudinal direction of the arm. In addition, one electrode 17a of the receiving device 2 is arranged so that a part (for example, a fingertip) of the human body M can be contacted, and the other electrode 17b of the receiving device 2 is not in contact with the human body M. It arrange | positions so that it may space apart from.

  The data communication device is configured to apply an alternating voltage modulated with data output from the control unit 20 to the pair of electrodes 17a and 17b. The data communication device also has a function of extracting data from the AC voltage applied to the pair of electrodes 17a and 17b and applying the data to the control unit 20. The reader / writer 50 also includes a data communication device (not shown) having the same configuration, and the reader / writer 50 is provided with a storage unit (not shown) for storing data received through the data communication device. The data communication apparatus also has a function of transmitting data stored in the storage unit.

  In order to perform data communication between the receiving device 2 and the reader / writer 50, the fingertip of the arm wearing the reader / writer 50 is brought into contact with the electrode 17a of the receiving device 2. In this state, a loop-shaped transmission path of electrode 17a-human body M-electrode 51a-human body M-electrode 51b-human body M- (capacitance between human body M and electrode 17b) -electrode 17b is formed. Considering the impedance included in this transmission path, there is an impedance Z1 due to the human body M between the electrode 17a and the electrode 51a, and an impedance Z2 due to the human body M between the electrodes 51a and 51b. Further, the electrode 17b and the human body M are not in contact with each other, but there is an impedance Z4 due to the capacitance between the electrode 17b and the human body M. The impedance between the electrode 51b and the electrode 17b includes the impedance Z3 due to the human body M in addition to the impedance Z4 due to capacitance. Further, the impedance Z5 due to the contact resistance between the electrode 17a and the human body M and the impedance Z6 due to the contact resistance between the electrodes 51a and 51b and the human body M are also included in the transmission path. In addition, the path | route shown with the broken line in FIG. 9 is also included between the electrode 51b and the electrode 17b.

  Since an AC voltage is applied to the electrodes 17a and 17b, data can be transmitted through a transmission path including an impedance Z4 due to capacitance (this type of so-called human body transmission technology is well known, for example, JP-A-2001-77735).

  By using the reader / writer 50 described above, the storage content stored in the storage unit 26 of the receiving device 2 can be read by the reader / writer 50. When reading the stored content from the receiving device 2 to the reader / writer 50, data communication is performed through the human body M, so to speak, so that there is little possibility of data leaking to the outside like a wireless transmission path, and data confidentiality. Becomes higher. Further, it is not necessary to connect a connector or the like as in the case of using a normal wired transmission line, and a person wearing the reader / writer 50 only needs to touch the electrode 17a with no need to attach or detach the cable. .

  Here, if the reader / writer 50 capable of communicating with the receiving device 2 is limited to the reader / writer 50 having the identification information registered in the receiving device 2 in advance, the stored contents of the receiving device 2 can be prevented from being read inadvertently. Therefore, the confidentiality of data is further increased. When the fingertip is brought into contact with the electrode 17a, the reader / writer 50 starts reading data by communicating between the receiving device 2 and the reader / writer 50, and when the data reading is finished, If the reader / writer 50 is notified of the end, the stored contents of the receiving device 2 can be reliably taken into the reader / writer 50. Of course, this notification may be performed by the receiving device 2.

  Data taken into the reader / writer 50 is taken out to a management device (not shown). Similar to the receiving device 2, the management device includes an electrode that contacts the human body M and a non-contact electrode that is coupled to the human body M by capacitance, and performs data communication with the reader / writer 50. Between the reader / writer 50 and the management device, the reader / writer 50 delivers the data read from the storage unit 26 of the receiving device 2 to the management device. In this case as well, the reader / writer 50 may notify the end of data transfer. Of course, this notification may be performed by the management device.

  With this configuration, a cable for connecting the reader / writer 50 and the management apparatus is not required, and data confidentiality when data communication is performed between the reader / writer 50 and the management apparatus can be ensured.

  In the configuration of the present embodiment, data is not directly exchanged between the management device and the receiving device 2 and the reader / writer 50 is interposed, so that the time of the clock unit 16 provided in the receiving device 2 is managed by the management device. However, it is not possible to automatically correct the time measured by the clock unit 17 of the receiving apparatus 2 using the time measured by the reader / writer 50 by providing the reader / writer 50 with a clock function. Is possible. Further, the time measured by the reader / writer 50 may be automatically corrected with the time measured by the management device.

  As described above, in this embodiment, there is no troublesome cable connection as in the case of using a wired transmission path, and data confidentiality is higher than in the case of using a wireless transmission path. Therefore, the convenience in transferring the unique information acquired by the receiving device 2 to the management device is enhanced. Other configurations and operations are the same as those in the first and second embodiments.

1 is a block diagram illustrating a first embodiment. It is a schematic block diagram which shows the usage example same as the above. It is operation | movement explanatory drawing same as the above. It is operation | movement explanatory drawing same as the above. It is sectional drawing which shows an example of the wave transmission element used for the same as the above. It is operation | movement explanatory drawing same as the above. An example of the wave receiving element used for the above is shown, (a) is a partially broken perspective view, and (b) is a sectional view. FIG. 6 is a block diagram illustrating a second embodiment. FIG. 6 is a schematic configuration diagram showing a third embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transmission apparatus 2 Reception apparatus 10 Control part 11 Density wave transmission part 12 Identification data transmission part 16 Clock part 17a Electrode 17b Electrode 20 Control part (position calculating part)
DESCRIPTION OF SYMBOLS 21 Density wave receiving part 22 Identification data receiving part 23 A / D converter 24 Data storage part 25 Timing control part 26 Interface 28 Specific information input part 27 Memory | storage part 40 Receiver element 50 Reader / writer M Human body Ob Detection object

Claims (5)

  Detects the relative position of the transmitter by receiving a sparse wave transmitted from the transmitter that is mounted on the detection target of the position detection and a transmitter that is fixed at a fixed position and intermittently transmits the sparse and dense waves And a management device that tracks the position to which the detection target has moved based on the position history obtained by the reception device, the transmission device includes a sparse / dense wave transmission unit that transmits a sparse / dense wave, and the reception device A sparse / dense wave reception comprising an array sensor in which a plurality of receiving elements for receiving the sparse / sparse wave transmitted from the sparse / dense wave transmission unit and converting the received sparse / dense wave into a reception signal as an electric signal are arranged. And a transmission device that obtains the direction of arrival of the sparse / dense wave to the sparse / received wave receiving unit based on the time difference between the reception times of the sparse / dense wave by the receiving elements of the sparse / dense wave receiving unit and the arrangement position of each receiving element It is equipped with a position calculation unit that calculates the distance to the A unique information input unit for inputting unique information for specifying a detection target, a storage unit for storing the history of the relative position of the transmission device obtained by the position calculation unit and the unique information input from the unique information input unit; A flow line measurement system comprising: an interface for retrieving stored contents through a non-wireless transmission path.   The transmission device includes an identification data transmission unit that transmits unique identification data using a wireless signal, and the reception device includes an identification data reception unit that receives identification data from the identification data transmission unit, and the position calculation 2. The flow line measurement system according to claim 1, wherein the unit obtains a distance from the transmission device based on a relationship between a reception time of the sparse / dense wave and a reception time of the identification data.   2. The receiving device includes a clock unit for measuring time, and stores the time measured by the clock unit in association with the relative position of the transmitting device in the storage unit. Alternatively, the flow line measurement system according to claim 2.   The interface has a function of transferring the contents stored in the storage unit to an external device and receiving time information from the external device, and the clock unit has a function of correcting time using the clock information from the external device. The flow line measurement system according to claim 3, wherein:   The interface includes an electrode that can be contacted by a human body, and a data communication device that enables data communication using a human body that has touched the electrode as a part of a transmission path between a reader / writer attached to the human body, 5. The flow line measurement system according to claim 1, wherein the reader / writer has a function of storing received data and a function of transmitting stored data.

Images