JP2010054439A - Flow line measuring system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent erroneous detection of received wave signals as precisely as possible even in cases of piezo-electric ultrasonic-generating elements having a property of received wave signals of initial lower rising and subsequent gradual growth. <P>SOLUTION: A first, a second and a third sensors S1, S2a and S3a are respectively linearly arranged along the right and left directions and a vertical direction perpendicular thereto on a substrate 1 of an array sensor 2, and when a wavelength of ultrasonic wave generated from an acoustic source is λ, the second sensor S2a is disposed at a space L of less than λ/2 from the first sensor S1 and the third sensor S3a is disposed at a space of n×λ (n: a natural number) from the first sensor S1. A control section 3 runs a prediction means obtaining a predicted value of a wave receiving time of the third sensor S3a by multiplying a difference of wave receiving times between the second sensor S2a and the first sensor S1 by n×λ/L and a confirmation means employing only the received wave signals detected within a predetermined period from the predicted value in the third sensor S3a as correct signals. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a flow line measurement system that uses ultrasonic waves to track the position of a moving object to be detected.

Conventionally, for example, as shown in Patent Document 1 below, a sound source that is mounted on a movable body that is a position detection target and that can generate ultrasonic waves, and a plurality of ultrasonic waves that are transmitted from the sound source and are converted into electrical signals. Each receiving element is arranged on the same substrate, and based on the time difference of the time when the receiving element of the ultrasonic array sensor received the ultrasonic wave and the arrangement position of each receiving element Thus, a flow line measurement system for obtaining the direction in which a moving body exists has been proposed.
JP 2007-127663 A

  FIG. 9 is a diagram showing a positional relationship between sensors A to C arranged on a substrate of a conventional ultrasonic array sensor, and the sensors A and C are arranged with a distance d. In FIG. 9, there is a sound source at a position rotated by an angle θ from the direction perpendicular to the plane on which the sensors A to C are arranged to the left. Since the distance to the sound source is sufficiently far compared with the distance between the sensors A to C, it can be considered that the ultrasonic waves 91 to 93 are incident substantially in parallel in FIG.

  Since the ultrasonic waves 91 to 93 are incident on the arrangement surfaces of the sensors A to C at an incident angle θ, for example, the time for the ultrasonic wave 93 to reach the sensor C is the time for the ultrasonic wave 91 to reach the sensor A. As compared with, the time is delayed by a time depending on the incident angle θ. Since the difference between the distances to the sound sources of the sensors A and C can be obtained by the equation of dsin θ, if the sound velocity is ν (about 340 m / s), the difference in the arrival times of the ultrasonic waves of the sensors A and C t Can be obtained by the equation t = dsin θ / ν.

  10 to 11 show the case where the array sensor of FIG. 9 receives the ultrasonic wave transmitted from the thermal excitation type ultrasonic wave generation element used as the sound source in the flow line measurement system of Patent Document 1. 2 shows the waveform of the received signal in FIG. In each figure, (a) shows the received signal of sensor A, (b) shows the received signal of sensor B, and (c) shows the received signal of sensor C.

  The thermal excitation type ultrasonic wave generating element energizes between the pads at both ends of the heating element layer to cause a temperature change in the heating element layer to generate ultrasonic waves, so that the energization to the heating element layer is appropriately controlled. Thus, the frequency of the ultrasonic wave generated can be changed over a wide range. In FIG. 11, the reverberation time is slightly longer, but it is also possible to generate an ultrasonic wave of approximately one cycle as shown in FIG.

  When the received signals of the sensors A to C are displayed on the same time axis as shown in FIGS. 10 to 11, they have a certain time delay. Therefore, for example, as shown in FIG. 10, when attention is paid to the first rise of each waveform, the rise waveform appears at a position delayed by a predetermined time in the order of the sensors A, B, and C. Since the time difference t in FIG. 10 is obtained by the calculation formula of t = dsin θ / ν, conversely, if the difference in the reception time of each sensor is known, in which direction the sound source exists ( The value of the incident angle θ). The flow line measurement system of Patent Document 1 tracks the position of a moving body by such a method.

  By the way, in Patent Document 1, for example, a thermal excitation type ultrasonic wave generating element whose initial rising waveform is large and clear as shown in FIG. 10 is used, but a commercially available piezoelectric ceramic element (for example, In the case of using a piezotite (registered trademark) manufactured by Murata Manufacturing Co., Ltd.) as an ultrasonic wave generating element, voltage application to the element is repeated a plurality of cycles like an AC voltage in order to increase sound pressure. For this reason, as shown in FIG. 12, the received signals of the sensors A to C have a very small initial rise (first wave), and then gradually increase and become maximum at, for example, the seventh to tenth waves. It has the nature of

  Therefore, in order to detect the first wave, it is necessary to set the threshold value of each sensor to a low level. However, if the threshold value is set to be low, the sensitivity of the sensor decreases, and as shown in FIG. In some cases, the second wave E1 may be erroneously detected without detecting a wave, or noise that is not a received signal may be picked up.

  For example, as shown in FIG. 13 (a), even if the threshold is set high so that the fourth wave can be detected, the waveform may be distorted depending on the sensor. As described above, the fifth wave E2 is detected, and there is a case where a half-wavelength shift occurs and a detection error occurs.

  The present invention has been made in view of the above-described conventional problems, and is not a thermal excitation type ultrasonic wave generating element in which the first rising edge (first wave) of a received signal appears largely and clearly, and is generally commercially available. It is an object of the present invention to provide a flow line measurement system capable of preventing erroneous detection of a received signal as much as possible even when a piezoelectric ultrasonic wave generating element is used.

  The problem to be solved is that erroneous detection of a received signal is caused even when a piezoelectric ultrasonic wave generating element having the property that the initial rise (first wave) of the received signal is small and then gradually increases is used. It is a point to prevent as much as possible.

In order to solve the above problems, the flow line measurement system of the present invention is:
An array sensor in which a sound source capable of generating an ultrasonic wave and a plurality of sensors that receive the ultrasonic wave transmitted from the sound source and convert it into a received signal that is an electric signal are two-dimensionally arranged on the same substrate And a control unit that analyzes the received signal, a flow line measuring system in which one of the sound source and the array sensor is mounted on a position detection target moving body, and the other is disposed at a predetermined position. Because
In the array sensor, first, second, and third sensors are linearly arranged in a horizontal direction on the substrate and a vertical direction perpendicular thereto, and the wavelength of the ultrasonic wave generated from the sound source is λ. The second sensor is arranged at an interval L of λ / 2 or less from the first sensor, and the third sensor is arranged at an interval of n × λ (n is a natural number) from the first sensor,
The control unit is configured to calculate a predicted value of the reception time of the third sensor by multiplying a difference between reception times of the second sensor and the first sensor by n × λ / L, and the third sensor And a confirmation means that adopts only a received signal detected within a predetermined time range from the predicted value as a correct signal,
The sound source is based on the difference between the reception time of the reception signal of the third sensor and the reception time of the first sensor, which is confirmed as a correct signal by the confirmation means, and the distance between the first and third sensors. The most important feature point is to obtain the incident angle of the ultrasonic wave transmitted from, and detect the position information of the moving body.

  According to the present invention, erroneous detection of a received signal is prevented as much as possible even when a piezoelectric ultrasonic generating element whose received signal gradually increases is used instead of a thermal excitation type ultrasonic generating element. can do.

  In the present invention, the reason why the distance between the sensors arranged on the substrate of the array sensor is specified as described above is as follows.

  When a thermal excitation type ultrasonic wave generating element is used, the first rising edge (first wave) of the received signal appears large and clearly, so that the first wave can be reliably detected, and the second wave and thereafter are detected. There is no risk of false detection. However, when a piezoelectric ultrasonic wave generating element is used, since the Q value of the resonance characteristics is large and reverberation is applied, voltage application to the element is repeatedly applied for a plurality of cycles like an AC voltage in order to increase sound pressure. The seventh to tenth waves may become the maximum value instead of one wave. That is, when a piezoelectric ultrasonic wave generating element is used, the first wave is not always the maximum, and when a waveform exceeding the sensor threshold value (assumed to be “the nth wave”) is detected, before and after that. The waveform (n + 1 wave or n-1 wave) may also be a signal having the same magnitude as the nth wave. Then, if the distance between the sensors is larger than λ / 2 (λ is the wavelength of the ultrasonic wave), whether the incident angle θ is detected at a positive angle of 0 ° or more, or the incident angle θ is It is difficult to determine whether the (n + 1) th wave is detected at a minus side angle of 0 ° or less. Therefore, in the present invention, first, the second sensor is disposed at a position of λ / 2 or less from the first sensor, and the n + 1-th wave and the n-1-th wave are erroneously detected for any incident angle θ. The risk of doing so was eliminated.

  However, when the distance between the sensors is λ / 2 or less, the time difference between the times when the ultrasonic waves reach each sensor becomes extremely small, and it is difficult to accurately detect the incident angle from the time difference. Therefore, in the present invention, the third sensor is arranged at a position spaced by n × λ (n is a natural number) from the first sensor. Further, according to the present invention, the control unit for analyzing the received signal output from the array sensor is multiplied by n × λ / L by the difference between the reception times of the second sensor and the first sensor. Prediction means for obtaining a predicted value of time and confirmation means for adopting only a received signal detected within a predetermined time range from the predicted value by the third sensor as a correct signal are provided.

  In this way, in the present invention, the difference between the reception time of the reception signal of the third sensor confirmed as a correct signal by the confirmation means and the reception time of the reception signal of the first sensor corresponding thereto, Based on the distance between the first sensor and the third sensor, the incident angle of the ultrasonic wave transmitted from the sound source can be obtained.

  Therefore, in the present invention, by setting an arbitrary threshold value sufficiently higher than the noise level of each sensor, when the first sensor detects a waveform (n-th wave) exceeding the threshold value, the second sensor The waveform (n + 1 wave or n-1 wave) is not erroneously detected, and a sufficient time difference is obtained between the first sensor and the third sensor, so a piezoelectric ultrasonic generator is used. Even in this case, the received signal can be detected with a certain accuracy.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view for explaining the configuration of the receiving unit of the flow line measurement system of this embodiment, and FIG. 2 is a view for explaining the positional relationship between a plurality of sensors arranged on the substrate of the array sensor.

  In FIG. 1, R is a receiving unit, which receives a plurality of sensors for receiving an ultrasonic wave transmitted from a sound source capable of generating an ultrasonic wave and converting the received ultrasonic wave into a received signal which is an electric signal. An array sensor 2 in which S1, S2a, S3a and sensors S2b, S3b (not shown in FIG. 1) are two-dimensionally arranged on the same substrate 1 and a received signal from the array sensor 2 are analyzed. It is comprised by the control part 3 and the housing | casing 4 which stores these apparatuses.

  The sensors S <b> 1, S <b> 2 a, and S <b> 3 a are disposed at positions in contact with the back surface of the upper surface plate 40 of the housing 4. As shown in FIG. 1, ultrasonic contact holes 41, 42a and 43a having a size smaller than the area of the upper surface of each sensor S1, S2a and S3a are provided at the contact position.

  FIG. 2 is a diagram for explaining the configuration of the array sensor 2. In the array sensor 2, the first sensor S1, the second sensor S2a, and the third sensor S3a are linearly arranged in the left-right direction on the substrate 1, and the first sensor S1, the second sensor S2b are also arranged in the vertical direction perpendicular to the first sensor S1, the second sensor S2a, and the third sensor S3a. The third sensors S3b are arranged linearly.

  The sensor arranged in the left-right direction arranges the second sensor S2a at an interval of λ / 2 from the first sensor S1 when the wavelength of the ultrasonic wave generated from the sound source is λ, and the third sensor S3a One sensor S1 is arranged at a distance of 3λ. As for the sensors arranged in the vertical direction, the second sensor S2b is arranged with an interval of λ / 2 from the first sensor S1, and the third sensor S3b is arranged with an interval of 3λ from the first sensor S1. ing.

  Although not shown in FIG. 1, the upper surface plate 40 of the housing 4 is provided with ultrasonic introduction holes similar to those of 41, 42a, and 43a in the portion where the sensors S2b and S3b are in contact. In the present embodiment, a total of five ultrasonic introduction holes are opened in the upper surface plate 40 and ultrasonic waves are formed on the upper portion of the upper surface plate 40 of the housing 4 so that dust and water do not enter the housing from the ultrasonic introduction holes. A permeable membrane 5 is attached. Details of the configuration of the ultrasonic introduction holes 41, 42a, 43a and the ultrasonic transmission film 5 will be described later.

  FIG. 3 is a block diagram illustrating the configuration of the transmission unit 6 and the reception unit R of the flow line measurement system of the present embodiment. In the flow line measurement system of the present embodiment, the position detection target is a moving body (for example, a shopping cart) that moves on a floor surface in a building such as a large store, and a sound source 61 that can generate ultrasonic waves intermittently. On the other hand, the receiving unit R having the array sensor 2 that receives the ultrasonic waves transmitted from the sound source 61 is used as a store wall, a pillar, a display shelf, a ceiling surface, etc. The relative position of the sound source 61 with respect to the receiving unit R is obtained, the movement state of the moving body is tracked, and the flow line is measured.

  The ultrasonic wave generating element of the sound source 61 uses Piezotite (registered trademark) manufactured by Murata Manufacturing Co., Ltd., which is a piezoelectric ceramic element. The transmission unit 6 includes a sound source 61, an ID transmission unit 62 that transmits a unique identification information signal, and a control unit 63 (microcomputer) that controls these drivers. The ID transmitter 62 is made of light, infrared rays, or radio waves, and also has a function of a trigger signal transmitter that transmits a trigger signal. The transmission start timing of the ultrasonic wave from the sound source 61 and the transmission timing of the identification information signal from the ID transmission unit 62 are controlled by mounting and executing an appropriate program on the microcomputer of the control unit 63.

  On the other hand, the receiving unit R includes the array sensor 2 described above, an ID receiving unit 7 that receives the identification information signal transmitted from the ID transmitting unit 62, an amplifier 8, and an AD converter that converts the input signal into digital data. Part 9 and a control part 3 (microcomputer) for controlling these drivers. The ID receiver 7 also has a function of a trigger signal receiver that receives the trigger signal transmitted from the ID transmitter 62. In the present invention, an appropriate program is mounted on the microcomputer of the control unit 3 that analyzes the received signal output from the array sensor 2, and the difference between the received times of the second sensor and the first sensor is expressed by n × λ / L. A prediction means for multiplying the third sensor to obtain a predicted value of the reception time of the third sensor, and a confirmation means for adopting only the received signal detected within the predetermined time range from the prediction value by the third sensor as a correct signal It was configured to make it. The “predetermined time range” allowed in the confirmation unit can be arbitrarily determined. For example, the “predetermined time range” can be set within the time range of the first and second half wavelengths based on the predicted value obtained by the prediction unit. If the received signal is not detected within the time range allowed by the confirmation means, it is determined that the received signal is not correct and error processing is performed.

  In the flow line measurement system of the present invention, as shown in FIG. 4, a plurality of receiving units R are installed at predetermined positions such as store walls, pillars, display shelves, and ceiling surfaces. Data relating to the relative position of the sound source 61 of each transmission unit 6 is converted into a predetermined data string via the AD converter unit 9 and the control unit 3 of the reception unit R, and further, wired or wireless via the output unit 10. The data is sent to the relay device 11 by communication, and finally output to a management device such as the computer device 12 through the LAN line. The output unit 10 may employ a serial transfer system interface such as RS / 485 or a parallel transfer system interface such as SCSI.

  The computer device 12 plots the position of the cart every predetermined time and grasps the flow line of the customer in the store. By using this system, it is possible to analyze the route by which the customer travels in the store to purchase the product using hourly data, so it is possible to determine the optimal product layout for efficiently selling the product. it can.

  In addition, although the present Example discloses the example in which the receiving unit R is installed at a fixed position such as a ceiling surface and the transmitting unit 6 is mounted on the moving body, these may be reversed. In the present invention, the receiving sensor R including the array sensor 2 can be mounted on a moving body, and the transmitting unit 6 including the sound source 61 can be disposed at a fixed position.

  Next, data processing of the flow line measurement system of the present invention will be described. FIG. 5 shows a plurality of sensors arranged on the substrate 1. In this embodiment, the distance between the sensors S1 and S2a arranged in the left-right direction is λ / 2, and the distance between the sensors S1 and S3a is 3λ. Each sensor is arranged so that the distance between the sensors S1 and S2b arranged in the vertical direction is λ / 2 and the distance between the sensors S1 and S3b is 3λ.

  Now, in FIG. 5, the ultrasonic waves 51, 52, 53 from the sound source 61 of the transmission unit 6 are rotated from the direction perpendicular to the plane on which the sensors S1, S2a, S3a are arranged to the left by an angle θ1. Incident. Since the distance to the sound source 61 is sufficiently far compared to the distance between the sensors, it can be considered that the ultrasonic waves 51 to 53 are incident substantially in parallel in FIG. Further, ultrasonic waves 54 and 55 different from the ultrasonic waves 51, 52 and 53 are incident from a direction rotated to the right side by an angle θ2 from a direction perpendicular to the surface on which the sensors S1, S2a and S3a are arranged. Yes. It can be considered that the ultrasonic waves 54 and 55 are also incident substantially in parallel.

  Since the ultrasonic waves 51 to 53 are incident on the arrangement surface of the sensors S1, S2a, and S3a at an incident angle θ1, the ultrasonic wave 51 reaches the sensor S1 during the time that the ultrasonic wave 53 reaches the sensor S3a. Compared to the time, it is delayed by a time depending on the incident angle θ. Therefore, if the difference between the reception times of the sensors is known, it is possible to know in which direction the sound source exists (value of the incident angle θ).

  FIG. 6 is a diagram for explaining the method of the present invention for obtaining the incident angle θ1 of the ultrasonic wave transmitted from the sound source 61. In FIG. First, an arbitrary threshold value sufficiently higher than the noise level of the first sensor S1 is set, and a point where the received signal exceeds the threshold value is set as P as shown in FIG.

  In this embodiment, the distance between the sensors S1 and S2a is λ / 2. Therefore, when the angles θ1 and θ2 are within ± 50 °, the detection signal of the sensor S2a appears at a position Q within half a wavelength from the point P. In the present invention, since the second sensor S2a is disposed at a distance of λ / 2 or less from the first sensor S1, there is no possibility of erroneously detecting the preceding and succeeding waveforms when a waveform exceeding the sensor threshold is detected. The waveform detected at the position Q within half a wavelength can be considered as a correct signal.

Next, in the present embodiment, since the distance between the sensors S1 and S3a is 3λ, the control unit 3 causes the received signal of the third sensor S3a to be at a time position R that is six times the time difference T _PQ between PQs. It can be predicted that it will be detected. And the control part 3 multiplies the difference of the receiving time of 2nd sensor S2a and 1st sensor S1, and calculates | requires the predicted value of the receiving time of 3rd sensor S3a, and the said 3 sensor S3a WHEREIN: Confirming means for adopting only a received signal detected within a time range corresponding to the first and second half wavelengths from the predicted value as a correct signal is executed.

In this embodiment, the incident angle θ1 of the ultrasonic wave transmitted from the sound source 61 is obtained based on the reception time of the third sensor S3a that has been confirmed to be a correct signal by the confirmation means. Specifically, θ1 can be obtained by the following calculation formula where T _{PR is} the difference in reception time between PRs in FIG. 6 and 340 m / s is the sound velocity.
3λ × sin θ1 = 340 × T _PR
sin θ1 = (340 × T _PR ) / 3λ
θ1 = sin ⁻¹ ((340 × T _PR ) / 3λ)

  Further, by performing the same process as described above between the sensors S1, S2b, and S3b arranged on the substrate 1 in the vertical direction, the direction in which the sound source 61 exists can be two-dimensionally grasped. Similarly, when the incident angle θ2 of the ultrasonic waves 54 and 55 incident from the minus side angle is obtained, it can be obtained by the above formula. However, in this case, as shown in FIG. 6, the second sensor S2a and the third sensor S3a receive the ultrasonic wave earlier than the first sensor S1, and therefore, in the graph of FIG. The point R appears at a position on the left side of the point P.

  Next, a more preferred embodiment of the ultrasonic wave introduction hole and the ultrasonic wave permeable membrane will be described with reference to FIGS. FIG. 7 shows that one rectangular large-sized ultrasonic wave introduction hole 70 including a plurality of sensors S 1, S 2 a, S 3 a, S 2 b, S 3 b arranged on the substrate 1 is formed on the upper surface plate 40 of the housing 4. The first embodiment in which the ultrasonic wave receiving part is configured by attaching the ultrasonically permeable film 5 for dustproofing and dripproofing to the opening part is shown. According to various studies by the present inventors, it has been found that the position detection accuracy in the first embodiment is lower than that in the second embodiment described later.

  The cause is that the ultrasonic wave entering from the ultrasonic wave introduction hole 70 having a large area is disposed on the substrate on which the ultrasonic transmission film 5 and the sensors S1, S2a, S3a are arranged as shown in FIG. 7B. 1 is repeatedly reflected several times to be input to the sensors S1, S2a, S3a, and is combined with the ultrasonic wave directly entering from the ultrasonic transmission film 5 without being reflected. This is because it may not be possible to correctly detect the azimuth from the phase of the sound wave.

  Therefore, in the present invention, it is most desirable to adopt the configuration of the second embodiment shown in FIG. In the second embodiment, the sensors S 1, S 2 a, S 3 a, S 2 b, S 3 b arranged on the substrate 1 are arranged at positions where they contact the back surface of the top plate 40 of the housing 4. As shown in FIG. 8, ultrasonic introduction holes 81, 82a, 83a, 82b, and 83b each having a smaller size than the area of the upper surface of the sensors S1, S2a, S3a, S2b, and S3b are provided at the positions. .

  If comprised in this way, since the ultrasonic introduction holes 81, 82a, 83a, 82b, and 83b are individually formed in the vicinity of each sensor, they are not combined with ultrasonic waves input from other positions, It is possible to correctly detect the ultrasonic phase difference due to the incident position, and it is possible to measure the position with high accuracy.

  In the case of the configuration of the second embodiment, when looking into the ultrasonic wave introduction hole from any external direction, the internal sensor becomes completely invisible, but the ultrasonic wave reaches each sensor by wraparound. There is no practical problem. Further, since the sizes of the ultrasonic introduction holes 81, 82a, 83a, 82b, and 83b are all equal, it can be considered that the paths reaching each sensor by wraparound are equal, so there is no problem in accuracy.

  The ultrasonic introduction holes 81, 82a, 83a, 82b, and 83b can have a desired shape such as a square shape or a round shape. Further, according to various studies by the present inventors, it has been found that, for example, when using an ultrasonic wave of 40 KHz, the side length or the diameter is preferably in the range of 1 to 4 mm. The guideline for designing the side length or diameter of the ultrasonic introduction hole varies depending on the frequency of the ultrasonic wave. However, when the wavelength of the ultrasonic wave is λ, it is preferable that the range is 1 mm or more and λ / 2 mm or less in the air. It is. If the ultrasonic frequency is 40 KHz and the sound speed is 340 m / s, the wavelength λ is about 8 mm. In this case, the side length or diameter is preferably in the range of 1 to 4 mm.

  As the ultrasonic transmission film 5, for example, a film made of polyethylene terephthalate is used, and the film thickness is desirably in the range of 1 μm to 6 μm. This is because when the thickness is in the range of 1 to 6 μm, the attenuation is small even when ultrasonic waves are transmitted, which is practically preferable.

  As described above, the flow line measurement system of the present invention has the first, second, and third sensors arranged linearly in the left-right direction on the substrate of the array sensor and the vertical direction orthogonal thereto, and When the wavelength of the ultrasonic wave generated from the sound source is λ, the second sensor is arranged at an interval L of λ / 2 or less from the first sensor, and the third sensor is n × λ from the first sensor. Since (n is a natural number), the received signal is erroneously detected even when a piezoelectric ultrasonic generator that gradually increases the received signal is used instead of the thermal excitation ultrasonic generator. Can be prevented as much as possible.

  In addition, a housing for storing the substrate, the array sensor, and the control unit is provided, and the first, second, and third sensors are disposed at a position in contact with the back surface of the upper surface plate of the housing, and at the disposed position. Is provided with ultrasonic introduction holes each having a size smaller than the area of the upper surface of the first, second, and third sensors, and an ultrasonic transmission film that covers the upper surface of the ultrasonic introduction holes. According to the line measurement system, even when an ultrasonic transmission membrane that protects the sensor for dustproof and dripproof purposes is attached, it is possible to correctly detect the ultrasonic phase difference depending on the incident position, and to measure the position accurately. Therefore, a more preferable effect can be obtained.

  The present invention is not limited to the above-described embodiments, and it is needless to say that the embodiments may be appropriately changed within the scope of the technical idea described in each claim. For example, the shape of the ultrasonic wave introduction hole is not limited to the round shape shown in the embodiment, and may be a square shape.

  The present invention is not limited to a system for analyzing the flow of a customer by attaching it to a shopping cart or the like. For example, an ultrasonic tag (transmission unit) is pasted on a part or device stored in a warehouse, and intermittently from the tag. The present invention can also be applied to a system for confirming the location of components and devices in real time by transmitting ultrasonic waves and ID signals and receiving them by a receiving unit. Moreover, it is applicable also to the alerting | reporting service etc. which notify a guardian of elderly person and a disabled person by giving a person an ultrasonic tag (transmission unit) and detecting a person's present position.

It is a figure explaining the structure of the receiving unit of the flow line measuring system of this invention. It is a figure explaining the positional relationship of the sensor arranged on the board | substrate of an array sensor. It is a block diagram explaining the structure of a transmission unit and a reception unit. It is the figure which showed the example which installs multiple receiving units in the ceiling surface of a store, etc. It is a figure explaining the state in which the ultrasonic wave is incident on the several sensor arranged on the board | substrate from the direction of angle (theta) 1 or (theta) 2. FIG. It is a figure explaining the system of this invention which calculates | requires the incident angle of the ultrasonic wave transmitted from the sound source. It is explanatory drawing of 1st Example which provided the ultrasonic introduction hole with a large area. It is explanatory drawing of 2nd Example which each provided the ultrasonic introduction hole with a small area. It is a figure which shows the positional relationship of the sensor arranged on the board | substrate of the conventional ultrasonic array sensor. It is the figure which displayed on the same time axis the waveform of the received signal of each sensor at the time of receiving the ultrasonic wave transmitted from the thermal excitation type ultrasonic wave generation element with an array sensor. It is a figure which shows the other example of the received signal from a thermal excitation type ultrasonic generation element. It is the figure which displayed on the same time-axis the waveform of the received signal of each sensor at the time of receiving the ultrasonic wave transmitted from the piezoelectric type ultrasonic wave generation element with an array sensor. It is a figure which shows the other example of the received signal from a piezoelectric type ultrasonic generation element.

Explanation of symbols

S1 1st sensor S2a, S2b 2nd sensor S3a, S3b 3rd sensor 1 Board 2 Array sensor 3 Control part 4 Case 40 Upper surface board 41, 42a, 43a Ultrasonic introduction hole 5 Ultrasonic transmission film 6 Transmission unit 61 Sound source 81 , 82a, 83a, 82b, 83b Ultrasonic introduction hole R receiving unit

Claims (4)

An array sensor in which a sound source capable of generating an ultrasonic wave and a plurality of sensors that receive the ultrasonic wave transmitted from the sound source and convert it into a received signal that is an electric signal are two-dimensionally arranged on the same substrate And a control unit that analyzes the received signal, a flow line measuring system in which one of the sound source and the array sensor is mounted on a position detection target moving body, and the other is disposed at a predetermined position. Because
In the array sensor, first, second, and third sensors are linearly arranged in a horizontal direction on the substrate and a vertical direction perpendicular thereto, and the wavelength of the ultrasonic wave generated from the sound source is λ. The second sensor is arranged at an interval L of λ / 2 or less from the first sensor, and the third sensor is arranged at an interval of n × λ (n is a natural number) from the first sensor,
The control unit is configured to calculate a predicted value of the reception time of the third sensor by multiplying a difference between reception times of the second sensor and the first sensor by n × λ / L, and the third sensor And a confirmation means that adopts only a received signal detected within a predetermined time range from the predicted value as a correct signal,
The sound source is based on the difference between the reception time of the reception signal of the third sensor and the reception time of the first sensor, which is confirmed as a correct signal by the confirmation means, and the distance between the first and third sensors. A flow line measurement system characterized in that an incident angle of an ultrasonic wave transmitted from the vehicle is obtained and position information of the moving body is detected.   A housing for housing the substrate, the array sensor, and the control unit, wherein the first, second, and third sensors are disposed at a position in contact with a back surface of an upper surface plate of the housing; Ultrasonic introduction holes each having a size smaller than the area of the upper surface of the first, second, and third sensors are provided at positions, and an ultrasonic transmission film that covers the upper surface of the ultrasonic introduction holes is further attached. The flow line measurement system according to claim 1.   The ultrasonic introduction hole has a square shape or a round shape, and the side length in the case of the square shape or the diameter in the case of the round shape is in a range of 1 mm to 4 mm. The flow line measurement system according to claim 2, wherein:   4. The flow line measurement system according to claim 2, wherein a film thickness of the ultrasonic transmission film is in a range of 1 μm to 6 μm.

Images