TWI728345B - Flexible sensor - Google Patents

Abstract

A flexible sensor includes a first elastic circuit module, a second elastic circuit module and a hot melt adhesive film. The first elastic circuit module includes a first elastic film and a first conductive pattern. The first elastic film can be stretched and elastically deformed and has a laminated printing carrier layer and a thermal bonding layer. The first conductive pattern is formed in a printing method by printing. Carrier surface. The second elastic circuit module includes a second elastic film and a second conductive pattern. The second elastic film can be stretched and elastically deformed. The second conductive pattern is formed on the second elastic film by printing and has the same shape and size as the first conductive pattern. Cooperate. The hot melt adhesive film is joined to the first elastic circuit module and the second elastic circuit module by thermocompression and can be stretched and elastically deformed together, and the positions of the first conductive pattern and the second conductive pattern correspond to the heat The melt glue film together constitutes the capacitor structure.

Description

Flexible sensor

The present invention relates to a flexible sensor, in particular to a flexible sensor that uses elastic deformation to generate capacitance or resistance.

The flexible sensor can be applied to a wearable electronic device. The flexible sensor can be elastically deformed with the expansion and contraction movement of the biological body or the joint flexion and extension movement to measure the biological information or movement information of the biological body. For example, Taiwan Patent Publication No. TW201701830A discloses an electrostatic capacitance sensor sheet, which includes a sensor body and a stretchable fabric integrated with the sensor body, and the sensor body has a sheet-like dielectric layer , A first electrode layer and a second electrode layer, the dielectric layer includes an elastomer composition, the first electrode layer and the second electrode layer are respectively formed on the surface and the back surface of the dielectric layer. The conductive material of the electrode layer adopts carbon nanotubes and is formed on the surface of the dielectric layer by coating. In addition, the fabric is laminated on the front and back sides of the sensor body through an adhesive layer.

As the aforementioned electrode layer of the sensor body is made by coating a conductive material on the surface of the dielectric layer, the manufacturing process is not only cumbersome and difficult to control. In addition, the sensor body needs to be glued with an adhesive layer when it is combined with the cloth, which is inconvenient in application.

Therefore, one of the objectives of the present invention is to provide a flexible sensor that is easy to manufacture and easy to combine with a carrier.

Therefore, in some embodiments, the flexible sensor of the present invention includes a first elastic circuit module, a second elastic circuit module, and a hot melt adhesive film. The first elastic circuit module includes a first elastic film and a first conductive pattern, the first elastic film can be stretched and elastically deformed and has a printed carrier layer and a thermal bonding layer laminated, the printed carrier layer For setting the first conductive pattern, the thermal bonding layer can be thermally melted and used to be combined with a carrier by hot pressing, and the first conductive pattern is formed on the surface of the printing carrier by printing. The second elastic circuit module includes a second elastic film and a second conductive pattern. The second elastic film can be elastically deformed by stretching. The second conductive pattern is formed on the second elastic film by printing and has a shape and size. Cooperate with the first conductive pattern. The hot-melt adhesive film is joined to the first elastic circuit module and the second elastic circuit module through a thermocompression bonding method and can be stretched and elastically deformed together. Two sides of the hot-melt adhesive film are respectively hot-melted with the The first conductive pattern and the second conductive pattern are joined, and the positions of the first conductive pattern and the second conductive pattern correspond to each other and form a capacitor structure together with the hot melt adhesive film.

In some embodiments, the second elastic film has the same structure as the first elastic film, and also has a printed carrier layer and a thermal bonding layer laminated, and the second conductive pattern is formed on the second elastic film by printing. The printed carrier surface of the elastic film.

In some embodiments, the first conductive pattern and the second conductive pattern are formed of conductive silver paste.

In some embodiments, the first conductive pattern has a plurality of sensing parts connected in parallel.

In some embodiments, the sensing parts together constitute a geometric figure and the geometric figure contains a plurality of hollow areas to separate the sensing parts.

In some implementations, the geometric figure is a quadrilateral and the hollow areas are linear and parallel to each other.

In some embodiments, the geometric figure is circular and the hollow areas are linear and parallel to each other.

In some implementations, the geometric figure is circular and the hollow areas are each arc-shaped and arranged rotationally symmetrically with the center of the circle.

In some embodiments, the first conductive pattern has a plurality of connected sensing parts, and each sensing part has at least one hollow area.

In some embodiments, each sensing part has a spiral shape.

In some embodiments, the flexible sensor of the present invention includes an elastic circuit module. The elastic circuit module includes an elastic film and a conductive pattern, the elastic film can be stretched and elastically deformed and has a printed carrier layer and a thermal bonding layer laminated to each other, the printed carrier layer is used to set the conductive pattern, the The thermal bonding layer can be thermally melted and used to be combined with a carrier by thermal compression. The conductive pattern is formed on the surface of the printed carrier by printing and is used for resistance sensing and has at least one sensing portion.

In some embodiments, a protective film is further included. The protective film covers the conductive pattern and can be stretched and elastically deformed together with the elastic circuit module.

In some embodiments, the protective film is a hot-melt adhesive film and is combined with the elastic circuit module in a thermocompression bonding manner.

In some embodiments, the protective film is formed by covering the conductive pattern with ink through printing.

In some embodiments, the conductive pattern is formed of conductive silver paste.

In some embodiments, the sensing portion is a curved circuit to increase the total length of the conductive path.

In some embodiments, the sensing part is mirror-symmetrical.

In some embodiments, the sensing part has a spiral shape with multiple turns from a center to the outside.

In some embodiments, the conductive pattern has a plurality of sensing parts arranged in parallel.

The present invention has at least the following effects: the elastic film of the elastic circuit module has a printed carrier layer to print a conductive pattern and a thermal bonding layer to be combined with the carrier by hot pressing, which not only facilitates the production of conductive patterns and makes the flexible sensor need not be recoated The cloth adhesive layer can be combined with the carrier, thereby increasing the ease of combining the flexible sensor with the carrier.

Before the present invention is described in detail, it should be noted that in the following description, similar elements are denoted by the same numbers.

Referring to FIGS. 1 and 2, a first embodiment of the flexible sensor 100 of the present invention is a capacitive sensor, which includes two elastic circuit modules 1 and a hot melt adhesive film 2. Each elastic circuit module 1 includes an elastic film 11 and a conductive pattern 12, the elastic film 11 can be elastically deformed by stretching, and has a printed carrier layer 111 and a thermal bonding layer 112 laminated, the printed carrier layer 111 is used to set the conductive pattern 12, the thermal bonding layer 112 can be thermally melted and used to be combined with a carrier 4 (see FIG. 3) by thermal compression, and the conductive pattern 12 is formed on the surface of the printing carrier layer 111 by printing. The material of the elastic film 11 can be, for example, polyurethane (PU), thermoplastic polyurethane (TPU), and the like. Since the printed carrier layer 111 must not be thermally deformed during the process of printing the conductive pattern 12 and the thermal bonding layer 112 and the carrier 4, the softening point of the printed carrier layer 111 needs to be higher than that of the printed conductive pattern 12. The process temperature and the thermal bonding temperature of the thermal bonding layer 112. In this embodiment, the main components of the printing carrier layer 111 and the thermal bonding layer 112 are polyurethane, but the softening point of the printing carrier layer 111 is 184°C, and the softening point of the thermal bonding layer 112 is 105°C. Moreover, in this embodiment, the thickness of the printing carrier layer 111 is about 44 μm, and the thickness of the thermal bonding layer 112 is about 45 μm.

The shapes and sizes of the conductive patterns 12 of the two elastic circuit modules 1 are matched, that is, the two conductive patterns 12 are mirror-symmetrical when they are arranged opposite to each other. For the convenience of description, only one of the conductive patterns 12 is described below. In this embodiment, the conductive pattern 12 is illustrated by taking a sensing portion 121 as an example, and the conductive pattern 12 further has a connecting portion 122 extending from the sensing portion 121, and the connecting portion 122 is used to connect an external wire (Not shown). In a modified embodiment, the conductive pattern 12 may have a plurality of sensing portions 121, which will be further described in the following embodiments. In this embodiment, the conductive pattern 12 is formed of conductive silver paste. The hot-melt adhesive film 2 is sandwiched between the two elastic circuit modules 1 and joined with the two elastic circuit modules 1 through a thermocompression method and can be stretched and elastically deformed together. The two sides of the hot melt adhesive film 2 are respectively joined with the conductive patterns 12 of the two elastic circuit modules 1 by hot melt. The positions of the conductive patterns 12 of the two elastic circuit modules 1 correspond to each other and form a capacitor structure together with the hot melt adhesive film 2. That is, the sensing portions 121 of the two conductive patterns 12 are two electrodes of the capacitor structure and heat The melt adhesive film 2 is the dielectric of the capacitor structure. Since the hot melt adhesive film 2 is joined to the conductive pattern 12 in a hot-melt manner, a better bonding force can be generated, and the entire capacitor structure can have better structural strength and reliability. . The deformation amount of the flexible sensor 100 can be calculated by measuring the change in the capacitance value of the flexible sensor 100.

Referring to Fig. 3, the production process flow of this embodiment is described:

First, prepare the elastic circuit module 1 and the hot melt adhesive film 2 respectively. When preparing the elastic circuit module 1, the elastic film 11 can be arranged on the substrate 3 to support the elastic film 11, and the thermal bonding layer 112 of the elastic film 11 is connected with the substrate 3 to expose the printing carrier layer 111, and then the conductive silver paste is printed A conductive pattern 12 is formed on the printed carrier layer 111 of the elastic film 11. Specifically, the substrate 3 is, for example, release paper.

Next, the two prepared elastic circuit modules 1 and the substrate 3 are arranged facing each other with the conductive patterns 12 and the hot melt adhesive film 2 is placed between the two elastic circuit modules 1, wherein the sensing portions 121 and the conductive patterns 12 of the two conductive patterns 12 are opposite to each other. The hot-melt adhesive film 2 is positioned up and down, and the hot-melt adhesive film 2 and the elastic circuit module 1 are thermally bonded and fixed by a hot pressing machine. After the hot melt adhesive film 2 is combined with the elastic circuit module 1, the hot melt adhesive film 2 is interposed between the sensing portions 121 of the two conductive patterns 12, and the connecting portion 122 of the two conductive patterns 12 is exposed outside the hot melt adhesive film 2 . In this way, the manufacture of the flexible sensor 100 can be completed. The substrate 3 can be used to protect the elastic film 11 and can be removed before being combined with the carrier 4. In addition, a larger area of the elastic film 11 can be used and multiple conductive patterns 12 can be printed at a time when the conductive pattern 12 is printed. After the elastic film 11 and the hot melt adhesive film 2 are combined, multiple flexible sensors 100 are formed, and then a knife is used. The die machine cuts to form a plurality of independent flexible sensors 100 and makes each flexible sensor 100 have an appropriate shape and size.

Further, the flexible sensor 100 can be combined with different carriers 4 according to usage requirements, and the carrier 4 can be, for example, cloth, shoe materials, and other materials used for wearing articles. To combine the flexible sensor 100 with applications (such as wrist guards, clothes, pants, hats, knee pads, shoes, etc.), first remove the substrate 3, and then cover the carrier 4 on the thermal bonding layer 112 of the elastic film 11 and The carrier 4 and the thermal bonding layer 112 are thermally bonded by thermal compression bonding. Although the two elastic films 11 have the same double-layer structure in this embodiment, in a modified embodiment, one of the elastic films 11 may have a single-layer structure for printing the conductive pattern 12, and only the other one has a single-layer structure. The combination of an elastic film 11 with a thermal bonding layer 112 and the carrier 4 can also be implemented.

Referring to FIG. 4, the difference between the second embodiment of a flexible sensor 100 of the present invention and the first embodiment is that, in the second embodiment, the conductive pattern 12 of each elastic circuit module 1 has a plurality of parallel-arranged conductive patterns 12 The sensing part 121 is used to increase the operating range of the flexible sensor 100. When preparing the elastic circuit module 1, a plurality of sensing portions 121 can be printed on the elastic film 11 and each sensing portion 121 extends a connecting portion 122, and then, the required number of sensing portions 121 can be added according to the use requirements. The other is connected with wires to form a parallel capacitor structure. In other words, when printing multiple sensing parts 121 on a large area of the elastic film 11, multiple independent capacitor structures can be fabricated at one time, and then multiple flexible senses each with a capacitor structure can be formed by cutting. For the sensor 100, some of the sensing parts 121 may also be connected in parallel by wires so that a single flexible sensor 100 has a plurality of capacitor structures connected in parallel. This can increase the flexibility of production and reduce the cost of stock preparation.

Referring to FIGS. 5 to 7, there are variations of the conductive pattern 12 of the first embodiment. The conductive pattern 12 has a plurality of sensing portions 121 connected in parallel. The sensing portions 121 collectively form a geometric figure and the geometric figure A plurality of hollow areas 125 are included to separate the sensing parts 121. As shown in FIG. 5, the geometric figure formed by the sensing portion 121 of the conductive pattern 12 is a quadrilateral, and the hollow areas 125 are linear and parallel to each other. As shown in FIG. 6, the geometric figure formed by the sensing portion 121 of the conductive pattern 12 is circular, and the hollow regions 125 are linear and parallel to each other. As shown in FIG. 7, the geometric figure formed by the sensing portion 121 of the conductive pattern 12 is circular, and the hollow regions 125 are arc-shaped and arranged in rotational symmetry with the center of the circle. A plurality of parallel-connected sensing parts 121 can detect the actions of the user at different positions and then connect them in parallel to the overall sensing signal. For example, the flexible sensor 100 is used to detect the degree of bending of the user’s knee. When it is smaller, only a few of the sensing parts 121 are stretched. When the knee bending is larger, more sensing parts 121 are stretched because of the total capacitance generated by the different stretched amounts of the sensing parts 121 The value also changes accordingly, so that the knee bending position can be judged.

Referring to FIGS. 8 to 10, there are variations of the conductive pattern 12 of the first embodiment. The conductive pattern 12 has a plurality of connected sensing portions 121 and each sensing portion 121 has at least one hollow area 125. The areas where the sensing parts 121 are distributed can be designed according to the parts to be sensed. Each sensing part 121 forms a local electrode. By using multiple local electrodes to correspond to multiple local areas that need to be sensed, local muscles and joints can be targeted. Do detection. As shown in FIG. 8, the conductive pattern 12 has three spiral-shaped sensing parts 121. As shown in FIG. 9, the conductive pattern 12 has two spiral-shaped sensing parts 121. As shown in FIG. 10, the conductive pattern 12 has two square sensing portions 121, and each sensing portion 121 has two hollow areas 125.

11 and 12, a third embodiment of the flexible sensor 100 of the present invention is a resistive sensor, which includes an elastic circuit module 1 and a protective film 2'. The difference between the elastic circuit module 1 of the third embodiment and the first embodiment is that the sensing portion 123 of the conductive pattern 12 of the third embodiment is a curved circuit to increase the total length of the conductive path, and the two sensing portions 123 Each end extends a connecting end 124 for connecting to an external wire (not shown), and the deformation of the flexible sensor 100 can be calculated by the change in resistance value generated when the sensing portion 123 is stretched. The protective film 2'covers the conductive pattern 12 and can be stretched and elastically deformed together with the elastic circuit module 1 to seal the conductive pattern 12 and waterproof. In a modified implementation aspect, it can be implemented without the protective film 2'. In the third embodiment, the protective film 2'is a hot-melt adhesive film and is combined with the elastic circuit module 1 in a thermocompression bonding manner. The manufacturing method of the third embodiment is substantially the same as that of the first embodiment, except that one elastic circuit module 1 is reduced. Similarly, in the third embodiment, the thermal bonding layer 112 of the elastic film 11 of the elastic circuit module 1 can also be thermally bonded to the carrier 4 (refer to FIG. 3). In a modified embodiment, the protective film 2'can also be formed by covering the conductive pattern 12 with ink through printing. The printing ink can cover the entire surface of the elastic film 11 or only partially cover the area of the conductive pattern 12 by printing. , As long as the conductive pattern 12 can be covered, and the ink can be an insulating material or a conductive material, which can be adjusted according to the needs of use.

In the third embodiment, the conductive pattern 12 is illustrated by taking one sensing portion 123 as an example. In a modified embodiment, the conductive pattern 12 may have multiple sensing portions 123 arranged in parallel to increase the flexibility of the flexible sensor 100. Scope of action. Similar to the aforementioned capacitive flexible sensor 100, in the third embodiment, when the conductive pattern 12 is printed on the elastic film 11, a plurality of independent sensing portions 123 can be printed at a time, and then cut according to usage requirements, if necessary When the multiple sensing parts 123 are in the same flexible sensor 100, the multiple sensing parts 123 can be connected in parallel by connecting wires to increase flexibility in manufacturing and reduce the cost of stock preparation.

Referring to FIGS. 13 and 14, the changes of the conductive pattern 12 of the third embodiment are shown. The sensing portion 123 shown in FIG. 13 and FIG. 14 is mirror-symmetrical, and the sensing portion 123 shown in FIG. 13 has a sinusoidal waveform. The sensing part 123 shown in FIG. 14 has a square waveform.

Referring to FIGS. 15 and 16 for the modified state of the conductive pattern 12 of the third embodiment, the sensing portion 123 shown in FIGS. 15 and 16 is in a spiral shape with multiple turns from a center to the outside, wherein the sensing portion shown in FIG. 15 The sensing portion 123 is a circular spiral, and the sensing portion 123 shown in FIG. 16 is a square spiral. The concentrically wound sensor 123 can detect local force changes.

Referring to FIG. 17, it is a variation of the conductive pattern 12 of the third embodiment. The sensing portion 123 forms two squares, which can detect two local areas, and can detect local force changes in different areas.

In summary, because the elastic film 11 of the elastic circuit module 1 has a printed carrier layer 111 for printing the conductive pattern 12 and a thermal bonding layer 112 for thermal compression bonding with the carrier 4, it is not only easy to fabricate the conductive pattern 12 but also enables flexible sensing The device 100 can be combined with the carrier 4 without being coated with an adhesive layer, thereby increasing the ease of combining the flexible sensor 100 with the carrier 4.

However, the above are only examples of the present invention. When the scope of implementation of the present invention cannot be limited by this, all simple equivalent changes and modifications made in accordance with the scope of the patent application of the present invention and the content of the patent specification still belong to This invention patent covers the scope.

100: Flexible sensor 1: Flexible circuit module 11: Elastic membrane 111: printed carrier 112: Thermal bonding layer 12: Conductive pattern 121: Sensing Department 122: connection part 123: Sensing Department 124: connection end 125: hollow area 2: Hot melt adhesive film 2’: Protective film 3: substrate 4: carrier

Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, in which: Fig. 1 is a schematic side view of a first embodiment of a flexible sensor of the present invention; Figure 2 is a three-dimensional exploded schematic view of the first embodiment; 3 is a schematic diagram illustrating the steps of the manufacturing method of the first embodiment; 4 is a schematic diagram illustrating a conductive pattern of a second embodiment of the flexible sensor of the present invention; 5 to 10 are schematic diagrams illustrating changes in the conductive pattern of the first embodiment; 11 is a schematic side view of a third embodiment of the flexible sensor of the present invention; FIG. 12 is a schematic diagram illustrating the conductive pattern of the third embodiment; and 13 to FIG. 17 are schematic diagrams illustrating the changing state of the conductive pattern of the third embodiment.

100: Flexible sensor

1: Flexible circuit module

11: Elastic membrane

111: printed carrier

112: Thermal bonding layer

12: Conductive pattern

121: Sensing Department

122: connection part

2: Hot melt adhesive film

Claims (19)

A flexible sensor, including: A first elastic circuit module includes a first elastic film and a first conductive pattern. The first elastic film can be stretched and elastically deformed and has a printed carrier layer and a thermal bonding layer laminated together. The printed carrier The layer is used to provide the first conductive pattern, the thermal bonding layer can be thermally melted and used to be combined with a carrier by thermal compression, and the first conductive pattern is formed on the surface of the printing carrier by printing; A second elastic circuit module, including a second elastic film and a second conductive pattern, the second elastic film can be stretched and elastically deformed, and the second conductive pattern is formed on the second elastic film by printing and has a shape The size matches the first conductive pattern; and A hot-melt adhesive film is joined to the first elastic circuit module and the second elastic circuit module through a hot pressing method and can be stretched and elastically deformed together. Both sides of the hot-melt adhesive film are respectively hot-melted with The first conductive pattern and the second conductive pattern are joined, and the positions of the first conductive pattern and the second conductive pattern correspond to each other and form a capacitor structure together with the hot melt adhesive film. The flexible sensor according to claim 1, wherein the second elastic film has the same structure as the first elastic film, and also has a printed carrier layer and a thermal bonding layer laminated, and the second conductive pattern is printed with The method is formed on the surface of the printing carrier layer of the second elastic film. The flexible sensor according to claim 1, wherein the first conductive pattern and the second conductive pattern are formed of conductive silver paste. The flexible sensor according to claim 1, wherein the first conductive pattern has a plurality of sensing parts connected in parallel. The flexible sensor according to claim 4, wherein the sensing parts jointly constitute a geometric figure and the geometric figure contains a plurality of hollow areas to separate the sensing parts. The flexible sensor according to claim 5, wherein the geometric figure is a quadrilateral and the hollow areas are linear and parallel to each other. The flexible sensor according to claim 5, wherein the geometric figure is circular and the hollow areas are linear and parallel to each other. The flexible sensor according to claim 5, wherein the geometric figure is circular and the hollow areas are each arc-shaped and arranged rotationally symmetrically with the center of the circle. The flexible sensor according to claim 1, wherein the first conductive pattern has a plurality of connected sensing parts, and each sensing part has at least one hollow area. The flexible sensor according to claim 9, wherein each of the sensing parts has a spiral shape. A flexible sensor, including: An elastic circuit module includes an elastic film and a conductive pattern, the elastic film can be stretched and elastically deformed and has a printed carrier layer and a thermal bonding layer laminated, and the printed carrier layer is used for arranging the conductive pattern, The thermal bonding layer can be thermally melted and used to be combined with a carrier by thermal compression. The conductive pattern is formed on the surface of the printed carrier by printing and is used for resistance sensing and has at least one sensing portion. According to claim 11, the flexible sensor further includes a protective film that covers the conductive pattern and can be stretched and elastically deformed together with the elastic circuit module. The flexible sensor according to claim 12, wherein the protective film is a hot-melt adhesive film and is combined with the elastic circuit module in a thermocompression bonding manner. The flexible sensor according to claim 12, wherein the protective film is formed by covering the conductive pattern with ink through printing. The flexible sensor according to claim 11, wherein the conductive pattern is formed of conductive silver paste. The flexible sensor according to claim 11, wherein the sensing portion is a curved circuit to increase the total length of the conductive path. The flexible sensor according to claim 16, wherein the sensor part is mirror-symmetrical. The flexible sensor according to claim 16, wherein the sensor portion is in a spiral shape that winds multiple times from a center to the outside. The flexible sensor according to claim 11, wherein the conductive pattern has a plurality of sensing parts arranged in parallel.

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