Monitoring system

A monitoring system for determining whether an object is touched by a living body includes a receiver and a piezoelectric sensor attached to a substrate such that when the substrate is attached to the object. The piezoelectric sensor generates an output signal as a function of whether the living body is in contact with at least one of the substrate and the object. A processor processes the output signal to determine whether the living body is in contact with at least one of the substrate and the object and outputs a contact information signal containing information indicative of whether the living body is in contact with at least one of the substrate and object based on the determination. A transmitter transmits the contact information signal to the receiver.

TECHNICAL FIELD

An embodiment of the present invention relates to a monitoring system including a piezoelectric contact sensor unit and a communication device.

BACKGROUND ART

There has conventionally been proposed a monitoring system that investigates which piece of goods is picked up by a customer among a plurality of pieces of goods displayed on a display shelf in a selling area of a shop.

For example, Japanese Patent Application Laid-Open No. 2005-328985 (“Patent Document 1”) discloses a monitoring system that reads information relating to movement of goods by using a non-contact IC tag attached to each of a plurality of pieces of goods displayed on a display shelf and an IC tag reader provided on the display shelf.

The monitoring system of Patent Document 1 reads information relating to movement of goods based on a frequency and a time period in which the goods are picked up by a customer. The monitoring system of Patent Document 1 performs a variety of types of calculation based on the information.

The monitoring system of Patent Document 1 cannot correctly determine whether goods are picked up by a customer or have merely been moved out of a detection range of the IC tag reader, depending on an installation position of the IC tag reader.

An object of an embodiment of the present invention is to provide a monitoring system that can reliably detect picking up of goods by a living body.

BRIEF SUMMARY OF THE INVENTION

In accordance with one aspect of the invention, a monitoring system for determining whether an object is touched by a living body includes:

a receiver;

a piezoelectric sensor attached to a substrate such that when the substrate is attached to the object, the piezoelectric sensor generates an output signal as a function of whether the living body is in contact with at least one of the substrate and the object;

a processor that processes the output signal to determine whether the living body is in contact with at least one of the substrate and the object and outputs a contact information signal containing information indicative of whether the living body is in contact with at least one of the substrate and object based on the determination;

a transmitter that transmits the contact information signal to the receiver.

In the preferred embodiment the piezoelectric sensor detects biological tremors of the living body when the living body is in contact with at least one of the substrate and the object and the output signal provides an indication of such detected biological tremors. In such a case, the processor determines whether the living body is in contact with at least one of the substrate and the object as a function of whether or not the output signal indicates that the biological tremors are detected.

In preferred embodiments, the piezoelectric sensor also detects bending forces applied to the substrate and the output signal provides an indication of such detected bending forces. In such a case, the processor determines whether the living body is in contact with at least one of the substrate and the object as a function of whether or not the output signal indicates that the biological tremors are detected and whether or not the output signal indicates that a predetermined level of bending forces have been applied to the substrate.

In an aspect of the invention, the information indicative of whether the living body is in contact with at least one of the substrate and object includes a determination that the object has been picked up.

In another aspect of the invention, information indicative of whether the living body is in contact with at least one of the substrate and object is determined as a function of the amount of time that the living body is in contact with the object.

In some embodiments, the object is a product. In another embodiment, the object is a display case.

In preferred embodiments, the receiver includes a display which displays information indicating that the living body has been in contact with at least one of the substrate and the object. The display can display information concerning the object. The information can be sales information.

In preferred embodiments, the monitoring system includes a memory that stores the contact information and the receiver includes a memory that stores the contact information provided in the contact information signal.

The receiver can include a notification unit that provides an indication that the living body is in contact with the object. The indication can be visual and/or audible.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a monitoring system according to a first embodiment of the present invention will be described.

FIG. 1is an external view of a monitoring system100according to the first embodiment of the present inventionFIG. 2is a side view of a piezoelectric contact sensor unit10shown inFIG. 1.FIG. 3is a front view of the piezoelectric contact sensor unit10shown inFIG. 1.FIG. 4is a block diagram of the piezoelectric contact sensor unit10shown inFIG. 1.FIG. 5is a block diagram of a host device150shown inFIG. 1.

As shown inFIG. 1, a monitoring system100includes the piezoelectric contact sensor unit10and a host device150. The monitoring system100determines whether a given product has been picked up by a customer and generates an output signal as a function thereof. Typically the product is one among a plurality of products displayed on a display shelf in a selling area of a shop. A respective piezoelectric contact sensor unit10is attached to at least one, and preferably all, of a plurality of products displayed on a display shelf. Thus, in the preferred embodiment, the monitoring system100includes a plurality of the piezoelectric contact sensor units10and the host device150.

Each piezoelectric contact sensor unit10includes a substrate11and a piezoelectric sensor35. The substrate11is preferably attached to the inside or a back surface of the product80so that a customer is not aware of the piezoelectric contact sensor unit10. The substrate11is attached to a section of the product80that is easily deformed when a customer picks up the product80.

The piezoelectric contact sensor unit10preferably has portable size and weight. For this reason, a salesperson can carry the piezoelectric contact sensor unit10and easily attach it to the product80. A customer can pick up and touch the product80to which the piezoelectric contact sensor unit10is attached and also can pick up and observe the product80from various angles.

In system terms, each of the piezoelectric contact sensor units10is a slave unit to the host device150. As shown inFIGS. 2 to 4, the piezoelectric contact sensor unit10includes the substrate11, a controller16, a memory17, a communication unit40, and a piezoelectric sensor35.

The host device150is what is called a master unit, and, as shown inFIG. 5, includes a communication unit140, a storage unit117, a controller116and a display155. The host device150is preferably installed, for example, in an administrative room of a shop. In the preferred embodiment, the controller is a CPU. However, other types of controllers can be used. When the controller is a CPU, the program for controlling the CPU is typically stored in the storage unit or memory117. The storage unit117is configured, for example, with a hard disk. The display155is configured, for example, with a liquid crystal monitor. By using the monitoring system100, a salesperson can check how much a customer is interested in each product more accurately. With a real-time situation transmitted to a mobile terminal held by a salesperson, the salesperson can serve a customer in consideration of degree of his or her interest in the product.

In the present embodiment, the piezoelectric sensor unit is used to determine whether a product80has been touched and/or picked up. However, the invention is not so limited. More generally the invention can be used to determine whether a living body (e.g., a person) has contacted and/or picked up an object. Examples of other objects are set forth in some of the embodiments disclosed herein.

As shown inFIGS. 1 to 3, the substrate11is preferably an insulating flexible plate, and is formed of polymer having comparatively high strength, such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), and acrylic resin (PMMA).

The substrate11preferably has a plate-like shape. A thickness of the substrate11is appropriately set in accordance with strength required for the substrate11. The controller16, the storage unit17, the communication unit40, and the piezoelectric sensor35are preferably mounted on a surface of the substrate11.

The controller16is configured, for example, with a microcomputer and includes a timer circuit (not shown). The storage unit17is configured, for example, with a flash memory. The storage unit17preferably stores a control program that is used by the microcomputer and controls the operation of each unit of the piezoelectric contact sensor unit10.

As shown inFIG. 3, the piezoelectric sensor35includes a rectangular piezoelectric film135. As best shown inFIG. 2, a signal electrode136and a GND electrode137are formed on opposite main surfaces of the piezoelectric film135. The signal electrode136is configured, for example, with a copper foil and an aluminum foil. The GND electrode137is configured, for example, with a conductive non-woven film. The GND electrode137is formed, for example, on a main surface of the piezoelectric film135by silver printing.

Since the substrate11can be significantly deformed, an organic electrode using ITO, ZnO, and polythiophene as main components, an organic electrode using polyaniline as a main component, a silver nanowire electrode, a carbon nanotube electrode, and the like are preferably used for the GND electrode137and the signal electrode136. By using the above materials, an electrode pattern excellent in flexibility can be formed.

The piezoelectric film135is preferably a piezoelectric film, and is preferably formed of uniaxially stretched polylactic acid (PLA) or L-type polylactic acid (PLLA).

The piezoelectric film135is formed of uniaxially stretched L-type polylactic acid (PLLA). In the present embodiment, the piezoelectric film135is uniaxially stretched in a direction that is substantially along a diagonal line of a rectangle (refer to an arrow shown inFIG. 3).

Hereinafter, the direction will be referred to as a uniaxially stretching direction901. The uniaxially stretching direction901preferably forms an angle of 45° with respect to a longitudinal direction or a lateral direction of the piezoelectric film135. However, the angle is not limited to the above, and may be designed to an optimum angle in consideration of a characteristic and a use state of the piezoelectric film135. For example, the uniaxially stretching direction preferably forms an angle of 45° with respect to a bending direction.

The angle is not limited strictly to 45°, and may be substantially 45°. The angle of substantially 45° includes, for example, an angle of around 45°±10°. The above angles are setting matters to be designed as appropriate in accordance with entire design, such as bending detection accuracy, based on a use of the piezoelectric contact sensor unit10.

The PLLA described above is a chiral polymer with a main chain having a spiral structure. The PLLA is uniaxially stretched and has piezoelectricity when molecules are oriented. The uniaxially stretched PLLA generates charges when a flat film surface of the piezoelectric film is pressed. An amount of charges generated at this time is uniquely determined based on an amount of displacement of the pressed flat film surface that is displaced in a direction orthogonal to the plat film surface. A piezoelectric constant of the uniaxially stretched PLLA belongs to a group having an extremely high piezoelectric constant among polymers.

Accordingly, a displacement of the piezoelectric film135caused by bending of the substrate11can be reliably detected at high sensitivity by using the PLLA. That is, bending of the substrate11can be reliably detected, and an amount of the bending can be detected with a high degree of sensitivity.

A stretching magnification is preferably around three to eight times. By applying heat treatment after stretching, crystallization of an extended-chain crystal of polylactic acid is promoted, and a piezoelectric constant is increased. When biaxial stretching is applied, stretching magnifications of axes are made different, so that an effect similar to that of uniaxial stretching can be obtained. For example, when stretching of eight times is applied in a direction as an x-axis and stretching of two times is applied in a y-axis direction orthogonal to the x-axis, an effect similar to that of uniaxial stretching of around four times applied to the x-axis direction can be obtained with respect to a piezoelectric constant. A film simply applied with uniaxial stretching is easily split along a stretching axis direction. Accordingly, by applying biaxial stretching, strength can be somewhat improved.

The PLLA generates piezoelectricity by molecule orientation processing by stretching and the like, and does not require polling processing to be performed like other polymers, such as PVDF, and piezoelectric ceramics. That is, piezoelectricity of the PLLA that does not belong to a ferroelectric substance does not express by polarization of ions like ferroelectric substances, such as PVDF and PZT, and derives from a spiral structure which is a characteristic structure of a molecule.

For this reason, pyroelectricity that is generated in other ferroelectric and piezoelectric substances is not generated in the PLLA. Further, in PVDF and the like, a temporal change is observed in a piezoelectric constant, and, in some cases, a piezoelectric constant is significantly lowered. However, a piezoelectric constant of the PLLA is extremely stable over time. Accordingly, deformation of the piezoelectric film135can be detected at high sensitivity without any influence from an ambient environment.

The PLLA has a high piezoelectric output constant (=piezoelectric g constant, g=d/εT). Accordingly, by using the PLLA, deformation of the piezoelectric film135can be detected at extremely high sensitivity.

The controller16may be mounted on any main surface of the substrate11, and is preferably disposed on the same surface as the piezoelectric sensor35. By disposing the piezoelectric sensor35and the controller16on the same surface, the piezoelectric sensor35and the controller16can be connected without using an interlayer connection conductor, such as a via hole having a large conductor loss. As a result, a weak signal from the piezoelectric sensor35can be detected with high accuracy.

Next, a method for using the piezoelectric sensor35to detect bending deformation of the substrate11will be described.

FIG. 6Ais a side view of the piezoelectric contact sensor unit10shown inFIG. 1.FIG. 6Bis a side view showing a state in which a customer bends the piezoelectric contact sensor unit10shown inFIG. 1. The bending amount of the piezoelectric contact sensor unit10is exaggerated inFIG. 6B.

As shown inFIG. 6A, when bending deformation is zero (i.e., the piezoelectric contact sensor unit10is not bent), the substrate11is in a flat state. In this case, the piezoelectric film135of the piezoelectric sensor35is neither stretched nor shrunk, and an output voltage from the piezoelectric sensor35does not indicate that the piezoelectric film has been deformed.

On the other hand, when a customer presses the center of the substrate11and bends the substrate11as shown inFIG. 6B, the substrate11is curved along a longitudinal direction. In this case, the piezoelectric film135of the piezoelectric sensor35is stretched or shrunk depending on a surface on which the piezoelectric sensor35is adhered to the substrate11and a bending direction with the result that the piezoelectric film generates an output (a charge).

The piezoelectric sensor35detects the charge generated on the signal and GND electrodes136and137of the piezoelectric film135and detects bending deformation of the substrate11as a function of this charge. When the charge meets certain criteria, the piezoelectric sensor35outputs a signal having a voltage value VM and indicating that the substrate11has been bent to the controller16.

The voltage value VM changes in accordance with the degree of deformation of the piezoelectric film135. As a result, the controller16can detect a deformation state of the piezoelectric film135from the voltage value VM. The voltage value VM is changed, for example, as described below.

When bending deformation is +a (i.e., the substrate11is bent in a positive direction by an amount a), the voltage value VM is +Va due to a relationship between the uniaxially stretching direction901and a bending direction (a longitudinal direction of the substrate11). When bending deformation is +b (i.e., the substrate11is bent in a positive direction by an amount b), +b being less than +a, the voltage value VM is +Vb which is less than +Va.

In this case, +Va and +Vb are, for example, in a relationship of 0<+Vth2<+Vth3<+Vb<+Vth1<+Va wherein +Vth1 is a first threshold value, +Vth2 is a second threshold value, and +Vth3 is a third threshold value. The first threshold value, the second threshold value, and the third threshold value will be described in detail below.

On the other hand, when bending deformation is −a (i.e., the substrate11is bent in a negative direction—that is, a direction opposite to the positive direction—by an amount a), the voltage value VM is −Va. When bending deformation is −b, the voltage value VM is −Vb which is greater than −Va (that is, it is more negative and of greater absolute value than −Va).

In this case, −Va and −Vb are, for example, in a relationship of 0>−Vth2>−Vth3>−Vb>−Vth1>−Va wherein −Vth1 is the first threshold value, −Vth2 is the second threshold value, and −Vth3 is the third threshold value. The first threshold value, the second threshold value, and the third threshold value will be described in detail below.

Accordingly, the controller16can detect both a bending direction and a bending amount by measuring the voltage value VM.

Next, a description of a method of detecting a minute vibration (what is called a biological tremor) of a living body that is generated when the living body is in contact with the substrate11or the product80will be described.

The controller16records the voltage value VM output from the piezoelectric sensor35as a signal on a time axis and converts the signal on the time axis to a signal on a frequency axis. The controller16determines whether or not a contact state, in which a living body is in contact with the substrate11or the product80, is established based on the signal on the frequency axis.

When a finger of a customer is in contact with the substrate11or the product80, a voltage showing a voltage change (minute vibration) of a certain frequency is output from the piezoelectric sensor35to the controller16.

A mechanical minute vibration (what is called a biological tremor) of a muscle exists as a physiological phenomenon of a living body. A biological tremor is a vibration of a certain frequency within a predetermined frequency band (for example, a band of around 5 to 20 Hz). A biological tremor is transmitted to the piezoelectric film135only when a finger (or other portion of the customer's hand) is in contact with the substrate11or the product80. The product80is assumed to be configured with a hard material by which a biological tremor is transmitted to the piezoelectric film135.

Accordingly, when a voltage output from the piezoelectric sensor35vibrates minutely at a frequency of around 5 to 20 Hz, the controller16determines that the piezoelectric sensor35detects a contact state in which a customer (typically the customer's hand or finger) is in contact with the substrate11or the product80.

A biological tremor is a phenomenon unique to a living body. If the piezoelectric sensor35outputs a voltage when an object other than a living body is in contact with the substrate11or the product80, and no frequency component is detected within a predetermined frequency band, the controller16determines that the piezoelectric sensor35does not detect a contact state.

Next, a description will be made of an example of a change in the output signal (pressing signal) of the piezoelectric sensor35while a customer holds the product80.

FIG. 7is a graph showing the change in an output signal of the piezoelectric sensor35when the product80is turned over by a customer.FIG. 8is a graph showing a change in the output signal of the piezoelectric sensor35when part of the product80is compressed by the customer.

The output signals shown inFIGS. 7 and 8are preferably obtained by applying a moving average to the actual output signal of the piezoelectric sensor35so that a noise component is erased and a tendency of a signal change is clearer. In this example, the output level when no displacement is generated in the product80(i.e., when the product is not moved) is 500.

As shown inFIG. 7, when a customer turns over the product80(in this case during the time period starting around the 29 seconds time period in the graph to the time period ending around 31 seconds in the graph), the output signal is changed significantly for a long period of time (i.e., a little over two seconds). The controller can use this information to determine whether the customer has turned over the product80. For example, when a standard of determining that a customer turns over the product80once is set to “an output of 700 is continuously exceeded for 0.5 second”, the controller16can detect (determine) that the product80has been turned over.

As shown inFIG. 8, when a customer compresses the product80for during a time interval extending from about 15 seconds on the graph to 19 seconds on the graph, the output signal changes in a manner that can be detected and a determination can be made that the customer has compressed the product. For example, when a standard of determining that a customer compresses (squeezes) the product80once is set to “a peak P in which an amplitude is 100 or larger than the non-deformed value (500) and 200 or smaller than the non-deformed value (500) is observed twice in one second”, the controller16can detect that the customer has compressed (e.g., squeezed) the product80.

The controller16can also detect the biological tremor described above from the output signals shown inFIGS. 7 and 8.

Next, a description will be made of operations performed by the controller16in the monitoring system100.

FIG. 9is a flowchart showing operations performed by the controller16shown inFIG. 4. The operation ofFIG. 9assumes a case where a customer shows an interest in the product80displayed on a display shelf in a selling area of a shop and the piezoelectric contact sensor unit10is attached to the product80.

When the piezoelectric sensor35outputs a signal, the controller16determines whether or not the output signal exceeds the first threshold value (S1). The first threshold value is set, for example, based on a level of a signal generated when the product80is moved from a state in which the product80is static. In the present embodiment, the first threshold value is +Vth1 and −Vth1 as described above.

Next, the controller16determines whether or not an output signal of the piezoelectric sensor35both (a) exceeds a second threshold value for a certain period of time and (b) minutely vibrates at a frequency of around 5 to 20 Hz (S2). When an output signal of the piezoelectric sensor35does not exceed the second threshold value for a certain period of time or does not minutely vibrate at a frequency of around 5 to 20 Hz, the controller16returns to S1and continues the processing.

The second threshold value is set, for example, based on a signal level of a minute vibration (biological tremor) generated when a living body is in contact with the substrate11or the product80. The second threshold value is smaller than the first threshold value. In the present embodiment, the second threshold value is +Vth2 and −Vth2 as described above. The certain period of time is, for example, two seconds. In S2, the controller16can reliably discriminate (determine) whether an output signal of the piezoelectric sensor35indicates that a customer has accidentally contacted the product80or actually picks up the product80.

Next, when an output signal from the piezoelectric sensor35exceeds the second threshold value for a certain period of time and minutely vibrates within a predetermined frequency band (for example, a band of around 5 to 20 Hz), the controller16determines that the piezoelectric sensor35detects a contact state in which a customer is in contact with the substrate11or the product80. The controller16starts measurement of a contact time by using a timer circuit (not shown) (S3). Specifically, the controller16records a contact start time at which a minute vibration starts to be detected in the storage unit17. The controller16then measures a moving time in which the product80is moved by the customer. During the moving time the minute vibration is detected (S4). For example, the controller16can determine that a customer holds and moves the product80when an output signal of the piezoelectric sensor35exceeds the third threshold value while the minute vibration is detected. When the moving time is large, a customer is considered to view the product80from various angles and check details of the product80.

For this reason, the controller16can determine that a customer has an interest in the product80. The third threshold value is set, for example, to a value between the second threshold value and the first threshold value. In the present embodiment, the third threshold value is +Vth3 and −Vth3 as described above.

Next, the controller16determines whether or not the customer has placed the product down. It does this by looking for an output signal of the piezoelectric sensor35which is lower than the second threshold value for a certain period of time (S5), for example two seconds. When a customer returns the product80to a product shelf, an output signal of the piezoelectric sensor35becomes lower than the second threshold value. For this reason, the controller16can reliably determine that a customer returns the product80. When an output signal of the piezoelectric sensor35is determined not to be lower than the second threshold value for a certain period of time, the controller16returns to S4and continues the processing.

Next, when an output signal of the piezoelectric sensor35is determined to be lower than the second threshold value for the certain period of time (i.e., the customer has placed the product down), the controller16calculates a contact time in which the customer held the product80based on the difference between the contact start time recorded in the storage unit17in S3and the current time shown by the timer circuit (not shown) (S6).

The controller16stores the contact time and the moving time in the storage unit17as the contact information (S7). The contact time and the moving time show the degree of interest that the customer has in the product80. For this reason, the controller16may calculate degree of interest a customer has in the product80based on the contact time and the moving time, and store the degree of interest in the storage unit17as the contact information.

Finally, the controller16transmits the contact time and the moving (movement) time as contact information to the host device150using the communication unit40(S8). The controller116of the host device150stores the contact information in the storage unit117. The controller116of the host device150displays the contact information on the display155. A salesperson can check the contact information on the display155.

The controller116may calculate degree of interest a customer has in the product80based on the contact and the moving times and store the degree of interest in the storage unit117or display the degree of interest on the display155as the contact information.

As described above, the monitoring system100can reliably detect that a customer has picked up the product80and can determine the degree of interest that the customer has in the product80. For this reason, a salesperson can grasp an inclination of a customer more in detail.

In the present embodiment, the controller16performs the processing of S1. However, the present invention is not limited to this configuration. When the present invention is implemented, the controller16may start from the processing of S2without performing the processing of S1.

Hereinafter, a monitoring system according to a second embodiment of the present invention will be described.

FIG. 10is an external view of a monitoring system200according to the second embodiment of the present invention.FIG. 11is a block diagram of a display device250shown inFIG. 10. The monitoring system200is different from the monitoring system100with in that it includes a display device250. The other configurations are the same, and will be omitted from the description.

The display device250(e.g., a tablet) includes a communication unit240, a storage unit217, a controller216, a display255, and a speaker256as shown inFIG. 11. The display device250is, for example, installed in a conspicuous location on a display shelf. The controller216is configured, for example, with a CPU. The storage unit217is configured, for example, with a flash memory. The display255is configured, for example, with a liquid crystal panel.

The display device250and a plurality of the piezoelectric contact sensor units10are connected, for example, by a wireless or wired LAN and transmits or receives predetermined information using the communication unit240.

Next, a description will be made on operation performed by the controller16in the monitoring system200.

FIG. 12is a flowchart showing operation performed by the controller16included in the piezoelectric contact sensor unit10shown inFIG. 10. The operation shown inFIG. 12is operation shown inFIG. 9to which S21and S22are added. The other processing is the same, and will be omitted from the description.

The controller16determines that the piezoelectric sensor35detects the contact state in which a customer is in contact with the substrate11or the product80in S2. After executing the processing of S3described above, the controller16transmits the contact information showing the contact state to the display device250via the communication unit40(S21).

The display255of the display device250displays goods information relating to goods when the communication unit240receives the contact information. For example, the display255displays, as goods information, characters, such as “Welcome”, and discount information. The controller216may reproduce a voice which is similar to a content displayed on the display255from the speaker256. A customer views and listens to the goods information on the display255and from the speaker256. In this manner, the monitoring system200can increase buying intention of a customer.

Next, after executing the processing of S7described above, the controller16transmits the contact information to the display device250by using the communication unit40(S22). The contact information includes degree of interest that another customer has on the product80.

The display255of the display device250displays goods information relating to goods when the communication unit240receives the contact information. For example, the display255displays, as goods information, characters, such as “Thank you”, and degree of interest that another customer has in the product80. The controller216may reproduce a voice which is similar to a content displayed on the display255from the speaker256. A customer views and listens to the goods information on the display255and from the speaker256. In this manner, the monitoring system200can increase buying intention of a customer.

As described above, the monitoring system200can attract a customer by using the display device250when a customer picks up the product80, so as to promote buying of the product80.

In the present embodiment, the controller16performs the processing of S1. However, the present invention is not limited to this configuration. When the present invention is implemented, the controller16may start from the processing of S2without performing the processing of S1.

Hereinafter, a monitoring system according to a third embodiment of the present invention will be described.

FIG. 13is an external view of a monitoring system300according to the third embodiment of the present invention. The monitoring system300is different from the monitoring system200in that the monitoring system300includes a showcase380and a display device350(in lieu of the display device250).

In the monitoring system300, the product80is contained in the showcase380. The piezoelectric contact sensor unit10is adhered to a back side (or other part of) the showcase380. A material of the showcase380is, for example, glass. The other configurations are the same, and will be omitted from the description.

A PLLA film used for the piezoelectric film135of the piezoelectric sensor35of the piezoelectric contact sensor unit10is a material having a high transmittance. For this reason, in the monitoring system300, the transparent piezoelectric contact sensor unit10can be implemented by configuring the signal electrode136, the GND electrode137, and the substrate11with a transparent material. The transparent piezoelectric contact sensor unit10does not lower visibility of the product80.

A configuration of the display device350is the same as the configuration of the display device250shown inFIG. 11. The display device350is, for example, a tablet. However, the display device350is carried, for example, by a salesperson. The other points are the same, and will be omitted from the description.

The display device350and a plurality of the piezoelectric contact sensor units10are connected, for example, by a wireless LAN. The display device350transmits or receives predetermined information using the communication unit240.

Next, a description will be made on operation performed by the controller16in the monitoring system300.

FIG. 14is a flowchart showing operation performed by the controller16included in the piezoelectric contact sensor unit10shown inFIG. 13. The operation shown inFIG. 14is substantially the same operation as that shown inFIG. 9, but steps S1and S4are deleted and S31is added.

When the piezoelectric sensor35on the piezoelectric contact sensor unit10outputs a signal, the controller16determines whether or not (a) the output signal exceeds the second threshold value for a certain period of time, and (b) the output signal minutely vibrates at a frequency of around 5 to 20 Hz (S2).

In S2, the controller16determines a signal of a minute vibration (biological tremor) generated when a living body is in contact with the showcase380. The second threshold value is set based on a signal level of a minute vibration (biological tremor) generated on the showcase380when a customer touches the showcase380.

When the controller determines that an output signal from the piezoelectric sensor35exceeds the second threshold value for a certain period of time and minutely vibrates within a predetermined frequency band (for example, a band of around 5 to 20 Hz), it determines that the piezoelectric sensor35detects a contact state in which a customer is in contact with the showcase380.

The controller16starts measurement of a contact time by using a timer circuit (not shown) (S3). Specifically, the controller16records a contact start time at which a minute vibration starts to be detected in the storage unit17.

Next, the controller16transmits the contact information showing the contact state to the display device350by using the communication unit40(S31).

The display255or the speaker256of the display device350notifies the contact state when the communication unit240receives the contact information. For example, the display255displays characters, such as “Customer touches a showcase”. The controller216may reproduce a voice which is similar to a content displayed on the display255from the speaker256.

Based on the notification, a salesperson can promptly serve a customer by, for example, preparing a key of the showcase380. In this manner, even when not being able to monitor the showcase380constantly, a salesperson can reliably grasp that a customer is studying closely the product80in front of the showcase380. For this reason, the monitoring system300can prevent a salesperson from missing a timing of serving a customer.

Next, the controller16determines whether or not an output signal of the piezoelectric sensor35is lower than the second threshold value for a certain period of time (S5). The certain period of time is, for example, two seconds. When a customer removes a hand from the showcase380, an output signal of the piezoelectric sensor35is lower than the second threshold value. For this reason, the controller16determines that a customer has moved away from the showcase380. When determining an output signal of the piezoelectric sensor35not to be lower than the second threshold value for a certain period of time, the controller16returns to S31and continues the processing.

Next, when determining an output signal of the piezoelectric sensor35to be lower than the second threshold value for a certain period of time, the controller16calculates a contact time in which a customer is in contact with the showcase380based on the contact start time recorded in the storage unit17in S3and a current time shown by the timer circuit (not shown) (S6).

The controller16stores the contact time in the storage unit17as the contact information (S7). The contact time shows degree of interest that a customer has in the product80. For this reason, the controller16may calculate degree of interest a customer has in the product80based on the contact time, and store the degree of interest in the storage unit17as the contact information.

Finally, the controller16transmits the contact time and the moving time as the contact information to the host device150by using the communication unit40(S8). The controller116of the host device150stores the contact information in the storage unit117. The controller116of the host device150displays the contact information on the display155. A salesperson checks the contact information on the display155.

The controller116may calculate degree of interest a customer has in the product80based on the contact time, and store the degree of interest in the storage unit117or display the degree of interest on the display155as the contact information.

As described above, a salesperson can reliably grasp that a customer shows an interest in the product80in the showcase380. For this reason, the monitoring system300can prevent a salesperson from missing a timing of serving a customer.

In the monitoring system300, a customer does not need to deform the substrate11of the piezoelectric contact sensor unit10. For this reason, the substrate11does not always need to have flexibility. Accordingly, the monitoring system300has an advantage that no damage is caused by bending deformation and the like which are performed repeatedly.

Hereinafter, a monitoring system according to a fourth embodiment of the present invention will be described.

FIG. 15is a front view of a piezoelectric contact sensor unit1010included in the monitoring system400according to the fourth embodiment of the present invention. The monitoring system400of the fourth embodiment is different from the monitoring system100of the first embodiment in that the piezoelectric contact sensor unit1010includes a sensor unit1035that detects twisting deformation of the substrate11in place of the piezoelectric sensor35that detects bending deformation of the substrate11. A difference between the sensor unit1035and the piezoelectric sensor35is a piezoelectric film1135. The other points of the monitoring system400are the same as those in the monitoring system100, and will be omitted from the description.

A uniaxially stretching direction902of the piezoelectric film1135is different from the uniaxially stretching direction901of the piezoelectric film135. The uniaxially stretching direction902of the piezoelectric film1135preferably forms an angle of 45° with respect to a diagonal line of the substrate11. The uniaxially stretching direction902may preferably form an angle of 0° with respect to a longitudinal direction or a lateral direction of the substrate11. However, the angle is not limited to the above, and may be designed as an appropriate angle in consideration of a characteristic and a use state of the piezoelectric film1135.

The angle of 0° with respect to a longitudinal direction or a lateral direction of the substrate11is not limited to exactly 0°, and may be substantially 0°. The angle of substantially 0° includes, for example, an angle of around 0°±10°. The above angles are setting matters to be designed as appropriate in accordance with entire design, such as detection accuracy for twisting, based on a use of the piezoelectric contact sensor unit1010.

When a customer applies an external force that twists the substrate11of the piezoelectric contact sensor unit1010, the substrate11is twisted around the uniaxially stretching direction902. In this case, the piezoelectric film1135of the sensor unit1035is stretched or shrunk.

For this reason, the sensor unit1035detects a charge generated on the signal electrode136and the GND electrode137of the piezoelectric film1135. In this manner, the sensor unit1035detects bending deformation of the substrate11. That is, the sensor unit1035detects a contact state in which a customer is in contact with the substrate11.

That is, in the piezoelectric contact sensor unit1010of the monitoring system400, the sensor unit1035detects both the biological tremor and twisting deformation. The sensor unit1035outputs a signal based on this detection to the controller16. When the sensor unit1035on the piezoelectric contact sensor unit1010outputs a signal, the controller16determines the output signal.

Operation of the controller16in the monitoring system400is the same as the operation (refer toFIG. 9) of the controller16in the monitoring system100, and will be omitted from the description.

The piezoelectric contact sensor unit1010may be used in place of the piezoelectric contact sensor unit10in the monitoring system200or the monitoring system300.

Hereinafter, a monitoring system according to a fifth embodiment of the present invention will be described.

FIG. 16is a side view of a piezoelectric contact sensor unit1110included in a monitoring system500according to the fifth embodiment of the present invention. The monitoring system500of the fifth embodiment is different from the monitoring system100of the first embodiment in that the piezoelectric contact sensor unit1110includes both the piezoelectric sensor35that detects bending deformation of the substrate11and the sensor unit1035that detects twisting deformation of the substrate11. The other points of the monitoring system500are the same as those in the monitoring system100, and will be omitted from the description.

In the piezoelectric contact sensor unit1110of the monitoring system500, the piezoelectric sensor35and the sensor unit1035detect three characteristics, i.e., the biological tremor described above, bending deformation, and twisting deformation. The piezoelectric sensor35and the sensor unit1035output a signal based on the detection to the controller16. When the piezoelectric sensor35and the sensor unit1035on the piezoelectric contact sensor unit1110output a signal, the controller16determines the output signal.

Operation of the controller16in the monitoring system500is the same as the operation (refer toFIG. 9) of the controller16in the monitoring system100, and will be omitted from the description.

The piezoelectric contact sensor unit1110may be used in place of the piezoelectric contact sensor unit10in the monitoring system200or the monitoring system300.

In the above embodiments, the description has been made on the case where the goods are a product80or the showcase380. However, the present invention is not limited to the above. When the present invention is implemented, for example, the goods may be other than a product (for example, an exhibit and the like).

Similarly, in the above embodiments, the description has been made on the case where the living body is a customer. However, the present invention is not limited to the above. When the present invention is implemented, for example, the living body may be a person other than a customer (for example, a thief and the like). The configuration may be such that, for example, when a force larger than assumed is detected to be applied to the substrate11, a thief is determined to destroy a showcase (an upper limit is set to a signal detected by the piezoelectric sensor35or the sensor unit1035, and a trouble is determined to be generated when a force that exceeds the upper limit is detected).

In the above embodiments, the description has been made on the example where the substrate11is formed of a hard material like, for example, a glass epoxy board. However, the present invention is not limited to this configuration. When the present invention is implemented, for example, the substrate11may be formed of a soft material like a resin film.

In the above embodiments, the piezoelectric element is configured with a piezoelectric film. However, the present invention is not limited to this configuration. When the present invention is implemented, for example, the piezoelectric element may be configured with piezoelectric ceramic and the like.

Hereinafter, a monitoring system according to a sixth embodiment of the present invention will be described.

FIG. 17is an external view of a monitoring system600according to the sixth embodiment of the present invention. The monitoring system600of the sixth embodiment is different from the monitoring system100of the first embodiment in that the piezoelectric contact sensor unit10and a host device1501are incorporated in a single housing801of, for example, a smartphone, and the piezoelectric contact sensor unit10and the host device1501are connected by wire. The function of the host device1501can be substituted by, for example, a CPU incorporated in a smartphone. The piezoelectric contact sensor unit10is adhered, for example, to an inner surface of the housing801of a smartphone. The sixth embodiment shows an embodiment as a smartphone. However, an application is not limited to a smartphone, and the present invention can also be applied to, for example, mobile terminals, such as a mouse, a clock, and a camera, a vacuum cleaner, a dryer, an electric bicycle, or equipment held by hand and operated, such as household electric appliances like an electric toothbrush.

An operation process of the present embodiment will be described hereinafter.

First, when pressing force is detected by the piezoelectric contact sensor unit10, processing associated with the piezoelectric contact sensor unit10is executed. The processing includes, for example, a wake-up function for a screen operation standby state, a volume adjustment standby state, and the like.

Next, execution of the processing associated with the piezoelectric contact sensor unit10triggers detection of a minute vibration (biological tremor). While the piezoelectric contact sensor unit10detects a minute vibration (biological tremor), a function associated with the piezoelectric contact sensor unit10is not finished even when a pressing operation detection is not applied for a certain period of time. The detection of a minute vibration (biological tremor) performed by the piezoelectric contact sensor unit10does not need to be always performed constantly, and may be performed at intervals of, for example, one to three seconds. At a time point at which no minute vibration (biological tremor) is detected by the piezoelectric contact sensor unit10, the function associated with the piezoelectric contact sensor unit10is finished.

For example, the configuration may be such that the function associated with the piezoelectric contact sensor unit10is finished when neither the minute vibration (biological tremor) nor the pressing operation have been detected for several seconds. It is advantageous to determine whether a person is holding the product by detecting a minute vibration (biological tremor) using the piezoelectric effect of the piezoelectric contact sensor unit10. However, there is a problem that the detection is easily influenced by noise caused by a vibration and the like of the surroundings. In order to mitigate this problem, the high sensitivity of the piezoelectric contact sensor unit10can be reduced during periods before the application of pressure to the piezoelectric contact sensor unit is detected using a CPU incorporated in a smartphone. To that end, the CPU sets a low-sensitivity mode until the application of pressure is detected and then switches the mode to a high-sensitivity mode once the application of pressure is detected. After switching is made from the low-sensitivity mode to the high-sensitivity mode, the high-sensitivity mode may be continuously set.

In another example, the CPU incorporated in the smartphone can prevent the erroneous operation by switching between the high-sensitivity mode and the low-sensitivity mode at predetermined periods of time. In this case, a distinction between whether a minute vibration (biological tremor) is detected by the piezoelectric contact sensor unit10or the detection is influenced by noise caused by a vibration of the surroundings and the like can be detected early as compared to when the modes are not switched at predetermined periods of time.

Hereinafter, a monitoring system according to a seventh embodiment of the present invention will be described.

FIG. 18is an external view of a monitoring system700according to the seventh embodiment of the present invention. The monitoring system700of the seventh embodiment is different from the monitoring system600of the sixth embodiment in that a pair of piezoelectric contact sensor units10,10are adhered to respective, different, inner surfaces of the housing801of a smartphone.

In the sixth embodiment, when unintended deformation, such as deformation of a bottom surface of the housing801, is made, the unintended deformation may be transmitted to the piezoelectric contact sensor unit10adhered to a side surface of the housing801and erroneous operation may be performed.

In view of the above, in the seventh embodiment, the piezoelectric contact sensor units10,10are disposed on various surfaces of the housing801of a smartphone and a difference between detection signals of the piezoelectric contact sensor units10,10is observed. In this manner, an operator can determine which surface of the housing801of a smartphone is being deformed.

Surfaces on which the piezoelectric contact sensor units10,10are disposed are not limited to those in the example ofFIG. 18. For example, the configuration may be such that the piezoelectric contact sensor units10,10are adhered to a substrate surface incorporated in a smartphone and a main surface and a housing side surface of a display, and a difference in detection signals of the piezoelectric contact sensor units10,10is observed.

Hereinafter, a monitoring system according to an eighth embodiment of the present invention will be described.

FIG. 19Ais a cross-sectional view showing an attaching structure of the piezoelectric contact sensor unit10included in a monitoring system800according to the eighth embodiment of the present invention to the housing801. In the present embodiment, the substrate11is adhered to an inner wall surface of the housing801of a smartphone by a double-sided tape, and the piezoelectric contact sensor unit10is attached to the substrate11. Size of the substrate11is larger than the piezoelectric contact sensor unit10. A GND electrode1371is formed on a surface of the substrate11to which the piezoelectric contact sensor unit10is not attached. A surface of the piezoelectric contact sensor unit10on which the GND electrode137is not formed (a surface on which the signal electrode136is formed) and a surface of the substrate11on which the GND electrode1371is not formed, are bonded. In a planar view, the GND electrode1371of the substrate11overlaps the piezoelectric contact sensor unit10and is larger than the piezoelectric contact sensor unit10. By the above configuration, noise from the outside of the housing can be prevented (or at least mitigated) from reaching the piezoelectric contact sensor unit10. That is, when a surface of the substrate11to which the piezoelectric contact sensor unit10is not attached is adhered at a position closer to an inner wall surface of the housing801of the smartphone than the piezoelectric contact sensor unit10, the risk that noise from the outside of the housing reaches the piezoelectric contact sensor unit10can be reduced.

FIG. 19Bis a cross-sectional view showing an attaching structure of the piezoelectric contact sensor unit10included in a monitoring system800according to the eighth embodiment of the present invention to the housing801. In the present embodiment, the piezoelectric contact sensor unit10is adhered to an inner wall surface of the housing801of a smartphone by a double-sided tape and the substrate11is attached in a manner of covering the piezoelectric contact sensor unit10. Size of the substrate11is larger than the piezoelectric contact sensor unit10. A GND electrode1371is formed on a surface of the substrate11to which the piezoelectric contact sensor unit10is not attached. A surface of the piezoelectric contact sensor unit10on which the GND electrode137is not formed (a surface on which the signal electrode136is formed) and a surface of the substrate11on which the GND electrode1371is not formed are bonded. In a planar view, the GND electrode1371of the substrate11overlaps the piezoelectric contact sensor unit10and is larger than the piezoelectric contact sensor unit10. As a result of the above configuration, noise from the inside of the housing can be prevented (or at least ameliorated) from reaching the piezoelectric contact sensor unit10. That is, when a surface of the substrate11to which the piezoelectric contact sensor unit10is not attached is adhered at a position closer to a center section of the housing801of the smartphone than the piezoelectric contact sensor unit10, the influence of noise from the inside of the housing can be restricted.

The description of the above embodiments are exemplifications in every aspect, and should be considered as not restrictive. The scope of the present invention is shown by the scope of claims, and not by the above embodiments. Further, the scope of the present invention includes a scope equal to the scope of the claims.

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