TWI653737B - Thin-film sensor - Google Patents

Abstract

The invention relates to a film sensor, comprising: two film substrates; at least two conductive layers respectively disposed on inner side faces of the two film substrates; a plurality of piezoelectric films, a plurality of piezoelectric films disposed on the two film bases Between the inner side surfaces of the material, the two sides of the piezoelectric film are respectively adhered to one side of the conductive layer relative to the film substrate through the conductive adhesive; when the film sensor of the present invention is bent, the piezoelectric film can follow the film substrate The bending deformation is generated together, and a plurality of piezoelectric films generate a sensing signal due to the piezoelectric effect.

Description

Thin film sensor

The invention relates to a film sensor, in particular to a film sensor for detecting motion or detecting strain and stress.

Most of the sensors currently used to detect motion or deformation on the market are made of mechanical switches or micro-electromechanical components, so their construction is quite complicated and expensive, and cannot be widely used.

Moreover, most of the existing sensors are relatively large in size, are not easily disposed on a space-constrained object, and must also be provided with a mount or a seat for mounting the sensor, thus causing considerable inconvenience in use.

In addition, although some thin film sensors appear on the market, the process technology used in this type of thin film sensor is quite complicated, which also causes the price to be lowered, which limits its use.

Due to the above reasons, the existing sensors are inconvenient to use, so how to solve the above problems through structural improvement has become one of the important issues to be solved by the business.

SUMMARY OF THE INVENTION A primary object of the present invention is to provide a thin film sensor which is simple in construction, low in cost, and easy to be thinned and can be mounted on various objects.

An embodiment of the present invention provides a thin film sensor, comprising: two film substrates, wherein the film substrates respectively have an inner side surface and an outer side surface, and the two film base materials are mutually opposite to each other At least two conductive layers, at least two of the conductive layers are respectively disposed on the inner side surfaces of the two film substrates; at least one piezoelectric film, at least one of the piezoelectric films is disposed on the two film bases Inner side of the material The two sides of the at least one of the piezoelectric films are respectively adhered to one side of the conductive layer relative to the two of the film substrates through a conductive adhesive, such that both sides of the piezoelectric film and the two conductive layers The surface of the film substrate is respectively provided with at least one circuit contact, and at least one of the circuit contacts of each of the film substrates is electrically connected to the conductive layer; When the film sensor is bent, at least one of the piezoelectric films can be bent along with the two film substrates, and at least one of the piezoelectric films generates a sensing signal due to a piezoelectric effect. The sensing signal generated by at least one of the piezoelectric films is conducted to the circuit contacts on the two film substrates via the two conductive layers.

In a preferred embodiment of the invention, the piezoelectric film is a polymeric material having piezoelectric properties.

In a preferred embodiment of the invention, the piezoelectric film is a polyvinylidene fluoride (PVDF) film.

In a preferred embodiment of the invention, the piezoelectric film is one of a polyvinyl chloride, a polyvinylidene fluoride, and a nylon film.

In a preferred embodiment of the present invention, the two film substrates are flexible polymer film substrates, and the two conductive layers are metal layers or metal oxide layers disposed on the surface of the film substrate.

In a preferred embodiment of the present invention, each of the conductive layers includes: at least one contact electrode portion, and at least one wire portion, wherein at least one of the contact electrode portions is disposed on an inner side surface of the film substrate and a position corresponding to at least one of the piezoelectric films, and an area of each of the contact electrode portions is larger than an area of at least one of the piezoelectric films, wherein a surface of at least one of the piezoelectric films is attached to the contact At least one of the wire portions is connected to at least one of the contact electrode portions and at least one of the circuit contacts for causing at least one of the contact electrode portions and at least one of the circuit contacts to be electrically connected to each other.

In a preferred embodiment of the present invention, two of the film substrates are elongated, and a plurality of the piezoelectric films and a plurality of the piezoelectric films are disposed between the two film substrates. Each of the two conductive layers has a plurality of contact electrode portions, and the plurality of the contact electrode portions respectively correspond to the plurality of piezoelectric thin films, and the plurality of the contact electrode portions respectively contact the plurality of The two sides of the piezoelectric film are described.

In a preferred embodiment of the present invention, each of the contact electrode portions is respectively connected to one of the lead portions, and the lead portion connected to each of the contact electrode portions is connected to another contact electrode portion. The wire portions are not connected to each other.

In a preferred embodiment of the present invention, at least one thin film piezoresistive element is disposed between the two film substrates, and at least one of the two sides of the thin film piezoresistive element is adhered through the conductive adhesive and the two conductive layers. And reach an electrical connection.

In a preferred embodiment of the invention, the film substrate is a flexible printed circuit board, and the conductive layer is a conductive line disposed on the flexible printed circuit board.

The invention has the advantages of simple structure, easy manufacture and low cost, and the thin film sensor of the invention can be widely used for various sensing purposes, and its structure can be easily attached and mounted on various articles. Therefore, it is widely used and extremely flexible.

For a better understanding of the features and technical aspects of the present invention, reference should be made to the accompanying drawings.

1‧‧‧Film sensor

10‧‧‧film substrate

20‧‧‧ Conductive layer

21‧‧‧Contact electrode

22‧‧‧Wire Department

23‧‧‧Circuit contacts

30‧‧‧Piezoelectric film

31‧‧‧ conductive adhesive

40‧‧‧Thin film piezoresistive elements

41‧‧‧Conductive adhesive

1 is a schematic cross-sectional view showing a first embodiment of a film sensor of the present invention.

2 is a partially enlarged plan view showing the first embodiment of the film sensor of the present invention.

3 is a schematic view showing the action of the first embodiment of the film sensor of the present invention in a state of being subjected to bending.

4 is a schematic plan view showing the first embodiment of the film sensor of the present invention.

Fig. 5 is a partially enlarged plan view showing the second embodiment of the film sensor of the present invention.

Figure 6 is a cross-sectional view showing the third embodiment of the film sensor of the present invention.

[First Embodiment]

As shown in FIGS. 1 and 2, the present invention provides a thin film sensor 1 having flexibility for detecting bending, displacement, or stress, strain, and the like of an object. As shown in FIG. 1, the film sensor 1 of the present invention comprises two film substrates 10, at least two conductive layers 20 disposed on the surface of the film substrate 10, and a plurality of piezoelectric films 30.

The film substrate 10 is made of a flexible polymer material. In this embodiment, the film substrate 10 is a flexible printed circuit board, and the conductive layer 20 is disposed on the flexible printed circuit. Conductive lines on the board. In particular, the film substrate 10 and the conductive layer 20 can also be formed by other methods. For example, the film substrate 10 can be made of various types of plastic or polymer materials, such as PET, PP, nylon, and the like. The conductive layer 20 can be plated or printed with a metal layer or a conductive material disposed on the surface of the film substrate 10.

The film substrate 10 has an inner side surface and an outer side surface, and the two film base materials 10 are superposed on each other with the inner side surfaces facing each other, and the two conductive layers are respectively disposed on the inner side surfaces of the two film substrates. A plurality of the piezoelectric thin films 30 are respectively disposed between the two conductive layers 20, thereby forming a sandwich structure in which the film substrate 10, the conductive layer 20, and the piezoelectric film 30 are combined.

As shown in FIG. 2, the conductive layer 20 is formed of a patterned conductor material disposed on the inner surface of the film substrate 10. In this embodiment, the conductive layer 20 includes a contact electrode portion 21 and a lead portion 22. The position where the contact electrode portion 21 is disposed on the film substrate 10 and the position of the piezoelectric film 30 correspond to each other, and the area of each of the contact electrode portions 21 is larger than the area of each of the piezoelectric films 30 so that the respective piezoelectric films 30 are Both side surfaces can be completely attached to the surfaces of the respective contact electrode portions 21.

In this embodiment, the two sides of the piezoelectric film 30 are adhered to the side of the contact electrode portion 21 of the conductive layer 20 with respect to the side of the film substrate 10 through the conductive paste 31, thereby causing the piezoelectric film 30 and the conductive layer 20 to be fixedly bonded, and Achieve an electrical connection.

The piezoelectric film 30 is made of a polymer material having piezoelectric characteristics, and may be, for example, selected from the group consisting of polyvinyl chloride, polyvinylidene fluoride, polyvinylidene fluoride (PVDF), nylon, etc., so that when the piezoelectric film 30 is subjected to When the force is deformed, two volumes of the piezoelectric film 30 can be The surface generates positive and negative opposite charges, thereby generating a sensing signal, and the sensing signal generated when the piezoelectric film 30 is deformed is conducted to the conductive layer 20 attached to both sides of the piezoelectric film 30 via the conductive adhesive.

Among the various piezoelectric materials having piezoelectric characteristics, preferred is polyvinylidene fluoride (PVDF), so that the piezoelectric film 30 is preferably implemented by using a polyvinylidene fluoride (PVDF) film material. .

As shown in FIG. 4, in this embodiment, the film substrate 10 is formed into a strip-like structure, and at least one circuit contact 23 is disposed at one end of the film substrate 10, and one end of the conductive layer 20 is connected through the wire portion 22. The circuit contact 23 is. The circuit contact 23 can be connected to the signal processing chip or the sensing circuit. After the plurality of piezoelectric films 30 are deformed by force to generate a sensing signal, the sensing signal can be transmitted through the wire portion 22 of the conductive layer 20. To the circuit contact 23 and the sensing circuit or signal processing chip connected to the circuit contact 23.

As shown in FIG. 3, when the film sensor 1 of the present invention is bent under force, the two film substrates 10 are bent, and the piezoelectric film 30 disposed between the two substrates is also bent together. The material inside the piezoelectric film 30 is subjected to compressive stress or tensile stress. When the piezoelectric film 30 is strained, a sensing signal can be generated, and both sides of the piezoelectric film 30 are adhered to the surface of the two conductive layers 20 through the conductive adhesive 31. Therefore, the sensing signal generated by the piezoelectric film 30 can pass through the conductive adhesive. 31 is transferred to the conductive layer 20 and transmitted to the circuit contact 23 disposed on the film substrate 10 via the conductive layer 20, and the sensing signal is further conducted to the signal processing chip or circuit via the circuit contact 23, thereby making the film feel The signal that the tester 1 is subjected to bending strain can be detected by the signal processing chip or the sensing circuit.

Of course, in addition to the bending deformation, the thin film sensor 1 of the present invention can also be used to detect a pressure or a gravity load. When the two sides of the thin film sensor 1 are pressed, the piezoelectricity is disposed between the two substrates. The film 30 also generates compressive strain and is capable of generating a sensing signal, thereby causing the film sensor 1 to be detected by the pressure action signal. Therefore, the film sensor 1 of the present invention has the following characteristics, first, the present invention The thin film sensor 1 has a simple structure and is therefore relatively inexpensive to manufacture; and the thin film sensor 1 of the present invention has flexibility and can be attached or disposed on a surface of a plurality of shapes, so that it is relatively easy to install and use. Further, the film sensor 1 of the present invention is made of a film material, so that it can be reduced in size, and thus it is possible to manufacture sensors of various sizes, and the application is used in various occasions.

The following is an example of various practical applications of the thin film sensor 1 of the present invention. For example, the thin film sensor 1 of the present invention can be used as a motion sensor for detecting a bending motion, or as a detecting bending strain or Stress sensor. When the film sensor 1 of the present invention is used as a bending motion sensor, the film sensor 1 of the present invention can be adhered to a bending action of an object to be detected (for example, a hinge of a cover or a door panel, Or the pivoting position of the connecting rod device, when the object to be detected generates a bending motion, a sensing signal can be generated by the film sensor 1 so that the bending motion is detected.

The film sensor 1 of the present invention can also be used to detect changes in compressive stress or weight load, for example, the film sensor of the present invention can be fabricated as a pressure sensitive pad, and the pressure sensitive pad can be placed on an elevated frame. The joint of the floor bracket and the raised floor enables the film sensor 1 of the present invention to detect a change in weight load when there is a load on the floor.

In addition, the film sensor 1 of the present invention can also be used as an anti-counterfeit or tamper-evident label. In this embodiment, the film sensor 1 of the present invention is designed as a stickable label and can be adhered to a packaging container or On the surface of the disassembled object, when the packaging container or object is detached, the film sensor 1 of the present invention is pulled to generate a sensing signal, so that the message that the container or object is disassembled is detected.

[Second embodiment]

As shown in FIG. 5, in the second embodiment of the film sensor 1 of the present invention, the film sensor 1 of the second embodiment of the present invention has a plurality of piezoelectric films 30, and the piezoelectric films 30 are arranged in a spaced relationship. It is disposed between the two film substrates 10. And the conductive layers 20 on the surfaces of the two film substrates 10 respectively have a plurality of contact electrode portions 21, and each contact electrode The position of the portion 21 corresponds to the plurality of piezoelectric thin films 30, and is adhered to both side faces of the plurality of piezoelectric thin films 30 through the conductive paste 31, respectively.

A second embodiment of the present invention is characterized in that a plurality of contact electrode portions 21 on each of the conductive layers 20 are respectively connected to a lead portion 22, and the lead portions 22 to which the respective contact electrode portions 21 are connected are not connected to each other, thus making each difference The contact electrode portions 21 are independent of each other, that is, when one of the piezoelectric films 30 of the thin film sensor 1 of the present invention generates a sensing signal, the sensing signals generated by the piezoelectric film 30 are only transmitted to and The piezoelectric film 30 that generates the signal is in contact with the electrode portion 21 without being conducted to the other contact electrode portion 21.

Therefore, when the thin film sensor 1 in the second embodiment is used, only the piezoelectric film 30 in which the film sensor 1 generates a deformation position generates a sensing signal, and the contact electrodes corresponding to the respective thin film sensors 1 The portion 21 transmits the sensing signal through the mutually independent lead portions 22, thereby enabling the signal processing circuit to easily recognize the position of the piezoelectric film 30 that emits the sensing signal, thereby detecting the position where the thin film sensor 1 is deformed. .

[Third embodiment]

As shown in FIG. 6 , in the third embodiment of the film sensor 1 of the present invention, the film sensor 1 of the third embodiment of the present invention further comprises a film piezoresistive element 40 between the two film substrates 10 . The film piezoresistive element 40 has a thickness and an appearance similar to that of the piezoelectric film 30, and is adhered to the surfaces of the two conductive layers 20 through the conductive paste 41.

The thin film piezoresistive element 40 is made of a piezoresistive material, and thus has a characteristic of changing impedance when deformed. In this embodiment, at least one thin film piezoresistive element 40 is disposed between the plurality of piezoelectric thin films 30, which will enable When the film sensor 1 is deformed, the impedance is changed by the film piezoresistive element 40, so that the sensing signal generated by the piezoelectric film 30 is changed by the impedance change.

[Possible effects of the examples]

As described above, the present invention has an advantageous effect in that it is simple in structure and easy to manufacture, and thus the film sensor 1 of the present invention is inexpensive and can be widely used. Moreover, the thin film sensor 1 of the present invention can be widely used for various sensing applications, and its configuration can be easily attached to various articles, thereby making it widely used and extremely flexible.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Therefore, equivalent technical changes made by using the present specification and the contents of the drawings are included in the protection scope of the present invention. .

Claims (9)

A film sensor comprising: two film substrates, each of the film substrates has an inner side and an outer side, and the film substrates are superposed on each other in such a manner that the inner sides are opposite to each other; at least two Conductive layer, at least two of the conductive layers are respectively disposed on the inner side surfaces of the two film substrates; at least one piezoelectric film, at least one of the piezoelectric films is disposed on the inner side surfaces of the two film substrates The two sides of the at least one of the piezoelectric films are respectively adhered to one side of the conductive layer relative to the two of the film substrates through a conductive adhesive, such that both sides of the piezoelectric film and the two conductive layers The surface of the film substrate is respectively provided with at least one circuit contact, and at least one of the circuit contacts of each of the film substrates is electrically connected to the conductive layer; When the film sensor is bent, at least one of the piezoelectric films can be bent along with the two film substrates, and at least one of the piezoelectric films generates a sensing signal due to a piezoelectric effect. At least one of The sensing signal generated by the electrical film is conducted to the circuit contacts on the two film substrates via at least two conductive layers; wherein each of the conductive layers comprises: at least one contact electrode portion, and at least a wire portion, wherein at least one of the contact electrode portions is disposed at a position corresponding to an inner side surface of the film substrate and at least one of the piezoelectric films, and an area of each of the contact electrode portions is greater than at least one of the pressure portions An area of the electric film for attaching a surface of the at least one piezoelectric film to a surface of the contact portion; at least one of the lead portions connecting at least one of the contact electrode portions and at least one of the circuit contacts The at least one of the contact electrode portions and the at least one of the circuit contacts are electrically connected to each other. The thin film sensor according to claim 1, wherein the piezoelectric film is made of a polymer material having piezoelectric properties. The thin film sensor according to claim 2, wherein the piezoelectric film is a polyvinylidene fluoride (PVDF) film. The thin film sensor according to claim 2, wherein the piezoelectric film is one selected from the group consisting of polyvinyl chloride, polyvinylidene fluoride, and nylon film. The film sensor according to any one of claims 1 to 4, wherein the two film substrates are flexible polymer film substrates, and the two conductive layers are disposed on the film substrate. a metal layer or a metal oxide layer on the surface. The film sensor according to claim 5, wherein two of the film substrates are elongated, and a plurality of the piezoelectric films are disposed between the two film substrates, and the plurality of piezoelectric films are mutually And at least two of the conductive layers respectively have a plurality of contact electrode portions, wherein the positions of the plurality of contact electrode portions respectively correspond to the plurality of piezoelectric thin films, and the plurality of the contact electrode portions respectively contact the plurality of The two sides of the piezoelectric film are described. The thin film sensor according to claim 6, wherein each of the conductive layers has a plurality of the contact electrode portions and a plurality of the lead portions, and each of the contact electrode portions is respectively connected to the lead portion And the wire portions to which the wire portion connected to each of the contact electrode portions and the other contact electrode portion are connected are not connected to each other. The film sensor according to claim 7, wherein at least one film piezoresistive element is disposed between the two film substrates, at least one side of the film piezoresistive element is transmitted through the conductive paste and the two conductive materials. The layers are bonded and electrically connected. The film sensor of claim 8, wherein the film substrate is a flexible printed circuit board, and the conductive layer is a conductive line disposed on the flexible printed circuit board.