Triboelectric device and corresponding method

Abstract

The first layer (110) and the second layer (120) comprise a first ridge surface (113) and a second ridge surface (123), respectively. The third layer (131) is sandwiched between the first ridge surface (113) and the second ridge surface (123) and is in physical contact with the first ridge surface (113) and the second ridge surface (123). The third layer (130) is elastically deformable and comprises a second triboelectric material (131). The first triboelectric material (111, 121) has an opposite charge type to the second triboelectric material (131). In the compressed state, the first ridge surface (113) and the second ridge surface (123) are adapted to cooperatively deform the third layer (130). In the released state, the first ridge surface (113) and the second ridge surface (123) provide a spacing between the first ridge surface (113) and the third layer (130) and between the second ridge surface (123) and the third layer (130). Each layer (110, 120, 130) further includes an electrode (114, 124, 134).

Description

Technical Field

[0001] Example embodiments relate to electronic devices and methods. Background Art

[0002] Electronic devices such as body activity monitors (e.g., smartwatches), physiological signal sensors (e.g., heart rate sensors, respiratory rate sensors), and implantable devices (e.g., hearing aids, pacemakers) may be used in the health, sports, and lifestyle industries. There is still a need for further development in this field. Summary of the Invention

[0003] The scope of protection sought by the various embodiments of the present invention is defined by the independent claims. Embodiments and features described in this specification that do not fall within the scope of the independent claims (if any) should be construed as examples to facilitate understanding of the various embodiments of the present invention.

[0004] According to a first aspect, an electronic device is described, the electronic device comprising: a first layer and a second layer, each layer comprising a first triboelectric material, wherein the first layer and the second layer comprise a first ridged surface and a second ridged surface respectively; a third layer, sandwiched between the first ridged surface and the second ridged surface and in physical contact with the first ridged surface and the second ridged surface, wherein the third layer is capable of elastic deformation and comprises a second triboelectric material, wherein the first triboelectric material has a charge type opposite to that of the second triboelectric material; wherein, in a compressed state, the first ridged surface and the second ridged surface are adapted to cooperatively deform the third layer; wherein, in a released state, the first ridged surface and the second ridged surface provide a spacing between the first ridged surface and the third layer and between the second ridged surface and the third layer; and wherein each layer further comprises an electrode.

[0005] The electronic device may further comprise an output terminal connected to the electrode.

[0006] The output terminal may be configured to provide a voltage pulse in response to a transition from the released state to the compressed state or vice versa.

[0007] One of the first triboelectric material and the second triboelectric material may be of a negative charge type, and the other of the first triboelectric material and the second triboelectric material may be of a positive charge type.

[0008] The triboelectric material of the negative charge type may comprise a silicone elastomer.

[0009] The triboelectric material of the positive charge type may comprise a thermoplastic polyurethane.

[0010] The first layer and the second layer may further comprise a plane adjacent to their respective ridged surfaces.

[0011] The electrodes of the first layer and the second layer can be respectively disposed on the planes of the first layer and the second layer.

[0012] The electronic device can further include a fourth layer and a fifth layer arranged to cover the electrodes of the first layer and the second layer.

[0013] The electrode of the third layer can be disposed within the third layer.

[0014] The electrode can include a stretchable material.

[0015] The stretchable material can be silver ink.

[0016] Each of the first ridged surface and the second ridged surface can include a ridge defined by protrusions and depressions.

[0017] In the compressed state, the protrusions of the first ridged surface can accommodate the depressions of the second ridged surface.

[0018] The protrusions and depressions can be sinusoidal peaks and valleys, triangular peaks and valleys, or square peaks and valleys within a given plane.

[0019] The electronic device can be a force sensor or can form part of a force sensor.

[0020] According to a second aspect, a method is described, the method comprising: providing a first layer and a second layer, each layer including a first triboelectric material, wherein the first layer and the second layer respectively include a first ridged surface and a second ridged surface; providing a third layer that is elastically deformable and includes a second triboelectric material, wherein the first triboelectric material has a charge type opposite to that of the second triboelectric material; disposing electrodes on or within each layer; sandwiching the third layer between the first ridged surface and the second ridged surface and physically contacting the first ridged surface and the second ridged surface, such that in the compressed state, the first ridged surface and the second ridged surface cooperatively deform the third layer, and such that in the released state, the first ridged surface and the second ridged surface provide a spacing between the first ridged surface and the third layer and between the second ridged surface and the third layer.

[0021] The method can further include providing output terminals connected to the electrodes.

[0022] The output terminals can be configured to provide voltage pulses in response to a transition from the released state to the compressed state or vice versa.

[0023] The method can further include: setting one of the first triboelectric material and the second triboelectric material to a negative charge type, and setting the other of the first triboelectric material and the second triboelectric material to a positive charge type.

[0024] The method can further include setting a silicone elastomer as the triboelectric material of the negative charge type.

[0025] The method may further include setting the thermoplastic polyurethane as a triboelectric material of a positive charge type.

[0026] The method may further include setting a plane adjacent to the respective ridged surfaces on the first layer and the second layer.

[0027] The method may further include setting an electrode of the first layer and an electrode of the second layer on the plane of the first layer and the plane of the second layer, respectively.

[0028] The method may further include setting a fourth layer and a fifth layer arranged to cover the electrodes of the first layer and the second layer.

[0029] The method may further include setting an electrode of the third layer within the third layer.

[0030] The method may further include setting an electrode including a stretchable material.

[0031] The method may further include setting the stretchable material as silver ink.

[0032] The method may further include setting ridges defined by protrusions and depressions for the first ridged surface and the second ridged surface.

[0033] The method may further include setting the protrusions of the first ridged surface such that, in a compressed state, it can accommodate the depressions of the second ridged surface.

[0034] The method may further include setting the protrusions and depressions as sinusoidal peaks and valleys, triangular peaks and valleys, or square peaks and valleys in a given plane.

[0035] The method may further include setting the electronic device as a force sensor or a part of a force sensor.

[0036] It should be understood that the above description is of currently considered preferred embodiments. However, it should be noted that the description of the preferred embodiments is given only by way of example, and various modifications can be made without departing from the scope defined by the appended claims. Description of the Drawings

[0037] Example embodiments will now be described by way of non - limiting examples with reference to the accompanying drawings, wherein:

[0038] Figure 1 is a schematic cross - sectional view showing an example embodiment of an electronic device;

[0039] Figure 2 shows an example embodiment of the electronic device transitioning between a fully compressed state and a fully released state;

[0040] Figure 3 shows an example embodiment of the electronic device in a perspective view;

[0041] Figure 4 An exemplary embodiment of an electronic device is shown in an enlarged perspective view;

[0042] Figure 5 (a) of shows an exemplary embodiment of an electronic device in cross-section;

[0043] Figure 5 (b) to (d) of are examples of graphs showing open-circuit voltage, short-circuit charge, and short-circuit current, respectively;

[0044] Figure 6 is an example of a graph showing the relationship between the theoretically calculated maximum contact area and the normal stress and the peak height;

[0045] Figure 7 is an example of a graph showing the relationship between the contact force and the peak height according to an exemplary embodiment;

[0046] Figure 8 (a) to (c) of are examples of graphs showing the output voltage, charge, and current, respectively, as a function of the compressive force according to an exemplary embodiment;

[0047] Figure 8 (d) of is an example of a graph showing the output current as a function of the force frequency according to an exemplary embodiment;

[0048] Figure 9 is an example of a graph showing the relationship between the theoretically calculated maximum contact force and the applied force for various exemplary embodiments having different ridge shapes;

[0049] Figure 10 is an example of a graph showing the relationship between the theoretically estimated ridge deformation and the contact force for various exemplary embodiments having different ridge shapes;

[0050] Figure 11 (a) of is an example of a graph showing the output voltage and current as a function of the resistance according to an exemplary embodiment;

[0051] Figure 11 (b) of is an example of a graph showing the output power density as a function of the resistance according to an exemplary embodiment;

[0052] Figure 11 (c) of is an example of a graph showing the output power density as a function of the resistance for various force frequencies according to an exemplary embodiment;

[0053] Figure 11 (d) of is an example of a graph showing the output voltage stability as a function of the number of force cycles according to an exemplary embodiment;

[0054] Figure 12 An electronic device that directly powers a set of LEDs according to an example embodiment is shown;

[0055] Figure 13 An electronic device that powers a calculator via a rectifier and a capacitor according to an example embodiment is shown;

[0056] Figure 14 (a) of shows an electronic device used as a respiratory monitoring force sensor according to an example embodiment;

[0057] Figure 14 (b) of shows an example of a sensing signal from the electronic device of (a) in use Figure 14 of the electronic device of (a);

[0058] Figure 15 (a) of shows an electronic device used as a pulse monitoring force sensor according to an example embodiment;

[0059] Figure 15 (b) of shows an example of a sensing signal from the electronic device of (a) in use Figure 15 of the electronic device of (a);

[0060] Figure 16 (a) of shows an electronic device used as a pressure sensing sole for gait analysis according to an example embodiment;

[0061] Figure 16 (b) of shows an example of a sensing signal from the electronic device of (a) in use Figure 16 of the electronic device of (a);

[0062] Figure 16 (c) of shows an example of a sensing signal from the electronic device of (a) in use Figure 16 of the electronic device of (a);

[0063] Figure 17 A method for developing the first and second layers of an electronic device according to an example embodiment is shown;

[0064] Figure 18 A method for developing the third layer or interlayer of an electronic device according to an example embodiment is shown. Detailed Description

[0065] Electronic devices such as body activity monitors (e.g., smartwatches), physiological signal sensors (e.g., heart rate sensors, respiratory rate sensors), and implantable devices (e.g., hearing aids, pacemakers) generally require a power source. Common power sources include commercial batteries, which can provide a limited amount of energy and rely on a charging source for continuous use.

[0066] The electronic device can be powered by a mechanical-electrical energy harvester (e.g., an electromagnetic, piezoelectric, or triboelectric nanogenerator).

[0067] The triboelectric nanogenerator utilizes the triboelectric effect. The triboelectric effect is based on the principles of contact electrification and electrostatic induction. When two different triboelectric materials come into contact under an applied mechanical force, contact electrification and electrostatic induction occur between their surfaces. Mechanical contact acquires electrical energy due to the difference in static charges on the surfaces of the contacting materials.

[0068] Figure 1 FIG. is a schematic cross-sectional view of an electronic device according to an exemplary embodiment, which is generally denoted by reference numeral 10. The electronic device 10 includes a first layer 110 and a second layer 120 sandwiching a third layer 130.

[0069] Each of the first layer 110 and the second layer 120 includes a first triboelectric material (denoted as 111 and 121, respectively). The triboelectric material 111 of the first layer 110 includes a flat surface / plane 112 and a first ridged surface 113. The first ridged surface 113 includes a generally sinusoidal cross-section, which includes peaks and valleys. Similarly, the triboelectric material 121 of the second layer 120 includes a flat surface / plane 122 and a second ridged surface 123. The second ridged surface 123 includes a generally sinusoidal cross-section, which includes peaks and valleys. When the first layer 110 and the second layer 120 are pressed together, the peaks and valleys of the first ridged surface 113 are arranged to cooperate with the peaks and valleys of the second ridged surface 123. In other words, the valleys of the first ridged surface 113 can accommodate the peaks of the second ridged surface 123. Similarly, the valleys of the second ridged surface 123 can accommodate the peaks of the first ridged surface 113.

[0070] The third layer 130 is sandwiched between the first ridged surface 113 and the second ridged surface 123 and is in physical contact with the first ridged surface 113 and the second ridged surface 123. The third layer 130 is capable of elastic deformation and includes a second triboelectric material 131. The first triboelectric materials 111 and 121 have a charge type opposite to that of the second triboelectric material 131; for example, the first triboelectric material 111 may include a negative charge type and the second triboelectric material 131 may include a positive charge type, and vice versa. The third layer 130 is capable of elastic deformation and includes two flat surfaces disposed on either side of the third layer 130. The first ridged surface 113 and the second ridged surface 123 contact the opposite flat surfaces of the third layer 130. In some embodiments, the third layer 130 may include a soft material, a stretchable material, and / or a viscoelastic material.

[0071] Each of the first layer 110, the second layer 120, and the third layer 130 includes an electrode (represented by reference numerals 114, 124, and 134, respectively). The frictional charge generated by the device flows through the electrodes to / from an external circuit connected to an electronic device. In some embodiments, the electrodes include stretchable materials. In some embodiments, the electrodes include stretchable silver ink. The electrodes 114, 124 of the first layer 110 and the second layer 120 are disposed on planes 112, 122, respectively, and are covered by a fourth additional layer and a fifth additional layer of the first triboelectric material 111 to protect the electrodes 114, 124. The electrode 134 of the third layer 130 is disposed inside the second triboelectric material 131 of the third layer 130.

[0072] Figure 2 An illustration shows the transition of the electronic device 201 according to an exemplary embodiment between a fully compressed state 210 and a fully released state 220. The electronic device 201 may be the same as or similar to the electronic device 100 Figure 1 associated therewith.

[0073] The flowchart includes four steps corresponding to the states of the electronic device 201 after applying and releasing a compressive force; these steps are labeled: i) fully compressed state, ii) released state, iii) fully released state, and iv) compressed state. As previously described, the electronic device 201 includes a first layer 202 and a second layer 203 sandwiching a third layer 204 that can elastically deform. The first layer 202 and the second layer 203 include negative triboelectric materials, and the third layer 204 includes a positive triboelectric material. The first layer 202 includes a flat surface 211 and a first ridged surface 212. Similarly, the second layer 203 includes a flat surface 213 and a second ridged surface 214. The first ridged surface 212 and the second ridged surface 214 are substantially sinusoidal in cross-section and are arranged such that when the first ridged surface 212 and the second ridged surface 214 are compressed together, the peaks and valleys of the first ridged surface 212 align with the valleys and peaks of the second ridged surface 214. The third layer 204 includes a shape that is substantially flat in its natural state (but can deform), having opposite surfaces 215 and 216. In all steps, the first ridged surface 212 is in physical contact with the surface 215, and the second ridged surface 214 is in physical contact with the surface 216. Each of the layers 202, 203, 204 includes an electrode 217, 218, 219, respectively. Each electrode 217, 218, 219 is connected to an output terminal 221 via a cable.

[0074] In the fully compressed state (step i), a compressive force is applied to the (outer) flat surfaces 211, 213, thereby compressing the third layer 204 between the first ridged surface 212 and the second ridged surface 214. The peaks and valleys of the first ridged surface 212 and the second ridged surface 214 cooperate to deform the third layer 204 that is capable of elastic deformation. Accordingly, the opposing surfaces 215, 216 of the third layer 204 are deformed; presenting a substantially sinusoidal shape, roughly corresponding to the peaks and valleys of the first ridged surface 212 and the second ridged surface 214. In this case, the first ridged surface 212 and the second ridged surface 214 may be in a state of maximum contact (or friction) with the opposing surfaces 215, 216 of the third layer 204. Due to triboelectrification, this may result in triboelectric charges of equal magnitude but opposite polarities being generated between the surface 212 and the surface 215 (negative charge on the surface 212 and positive charge on the surface 215), and similarly, triboelectric charges of equal magnitude but opposite polarities are generated between the surface 214 and the surface 216 (negative charge on the surface 214 and positive charge on the surface 216). Accordingly, the surface charges can be completely neutralized, such that no current flows from the electrodes to the output terminal 221.

[0075] In the released state (step ii), the compressive force (applied during step i) is released, and thus the deformed third layer 204 begins to elastically recover, i.e., returns to its default (substantially flat) shape (or a shape similar to the default shape), forcing the first layer 202 and the second layer 203 to separate from the third layer 204. When the first layer 202 and the second layer 203 separate from the third layer 204, a gap is formed between the surfaces 212, 215 and the surfaces 214, 216. The gap / spacing between the surfaces 212, 215 and the surfaces 214, 216 disrupts the charge balance on their respective surfaces. These perturbed surface charges generate a negative polarity on the electrode 219 and a positive polarity on the electrodes 217 and 218. This polarity causes a voltage pulse and current to flow from the negative electrode 219 to the positive electrodes 217 and 218.

[0076] In the fully released state (step iii), the third layer 204 is completely relaxed and has returned to a substantially flat shape or a similar shape. The surface charge distribution of the layers 202, 203, and 204 is in an equilibrium state, and thus no current flows out from the corresponding electrodes 217, 218, 219.

[0077] In the compressed state (step iv), a compressive force is again applied to the (outer) flat surfaces 211, 213, thereby compressing and deforming the third layer 204 between the first ridged surface 212 and the second ridged surface 214. The balance of the surface charge distribution is disrupted again. Accordingly, in order to restore the surface charge balance, the first layer 202 and the second layer 203 collect electrons from the third layer 204 through a current path from the electrodes 217 and 218 via the output terminal 221 to the electrode 219.

[0078] In some embodiments, once the pressure is released in a repeatable manner, the third layer elastically returns to its original state.

[0079] In some embodiments, under continuous cycles of compression and release of pressure, the third layer deforms and recovers through the first ridged surface and the second ridged surface, and these processes can be repeated in a cyclic manner.

[0080] In some embodiments, during the cyclic contact and separation between the third layer and the other first and second layers, charges are generated on its surface due to the triboelectric effect.

[0081] The continuous cyclic compressive force applied and released on the electronic device 201 causes an alternating current (AC) to be generated from the electrodes 217, 218, 219 to the output terminal 221 when the electronic device 201 transitions from the compressed state to the released state (and vice versa). The compressed state can be the fully compressed state as described above or a partially compressed state. In the partially compressed state, the ridged surfaces 212, 214 do not come into full contact with the third layer 204, so some gaps are retained. The released state can be the fully released state as described above or a partially released state. In the partially released state, the third layer 204 is not fully relaxed and remains under some stress from the ridged surfaces 212, 214. Compared with the fully compressed state or the fully released state, if the device 201 cyclically experiences a partially compressed state and / or a partially released state, the amplitude of the output signal from the device 201 may be lower.

[0082] Figure 3 A perspective view shows an electronic device according to an exemplary embodiment, which is generally denoted by the reference numeral 300. The electronic device 300 can be the same as or similar to Figure 1 and Figure 2 the electronic devices 100 or 201 in. The electronic device 300 includes a first layer 310 and a second layer 320, each layer including a first triboelectric material 301. The first layer 310 and the second layer 320 respectively include a first ridged surface 311 and a second ridged surface 321. A third layer 330 is sandwiched between the first ridged surface 311 and the second ridged surface 321 and is in physical contact with the first ridged surface 311 and the second ridged surface 321. The third layer 330 includes a second triboelectric material 302. The first triboelectric material 301 has a charge type opposite to that of the second triboelectric material 302.

[0083] The first ridged surface 311 and the second ridged surface 321 include ridges defined by protrusions and depressions. The protrusions of the first ridged surface 311 are arranged to mate with the depressions of the second ridged surface 321 (and vice versa) to deform the third layer 330 when the electronic device 300 is in a compressed state. In other words, the depressions of the second ridged surface 321 are arranged to receive the protrusions of the first ridged surface 311, and vice versa. In some embodiments, the protrusions and depressions form generally sinusoidal peaks and valleys in cross-section. In some embodiments, the first ridged surface 311 and the second ridged surface 321 include a plurality of sinusoidal peaks and valleys. In some embodiments, the peaks are symmetric about a central axis. In some embodiments, the plurality of peaks and valleys are arranged in a two-dimensional lattice (e.g., an equilateral triangle lattice). It should be noted that the generally sinusoidal arrangement of the peaks and valleys provided by the ridged surfaces of the electronic device 300 is not essential for all exemplary embodiments. In some embodiments, ridges (in cross-section) including triangles, squares, or other shapes may be used. In some embodiments, the shape and / or size of the ridges may depend on the input compressive force applied to the electronic device 300.

[0084] As described with respect to Figure 2 the electronic device 300 can be compressed and released in a continuous cycle to generate alternating current.

[0085] Figure 4 An electronic device according to an exemplary embodiment is shown in an enlarged perspective view and is generally designated by the reference numeral 400. The electronic device 400 can be the same as or similar to the electronic device 300 associated with Figure 3 As previously described, the electronic device 400 includes a first layer 410 and a second layer 420 sandwiching a third layer 430.

[0086] The first layer 410 includes an electrode 412 laminated on a layer of silicone elastomer (e.g., (00 - 30)) 413. The electrode 412 can include a stretchable silver ink sheet. The silicone elastomer is a negative triboelectric material. The silicone elastomer 413 includes a flat surface / plane and a first ridged surface (similar to the surface 311 described with respect to Figure 3 )). An additional layer of silicone elastomer 411 is coated on top of the electrode 412 to protect the electrode 412 from mechanical wear. Thus, the electrode 412 is encapsulated within the first layer 410.

[0087] Similarly, the second layer 420 includes an electrode 422 laminated on a layer of silicone elastomer (e.g., (00 - 30)) 423. The electrode 422 can include a stretchable silver ink sheet. The silicone elastomer is a negative triboelectric material. The silicone elastomer 423 includes a flat surface / plane and a second ridged surface (similar to the surface Figure 3The described surface 311). An additional silicone elastomer layer 421 is coated on top of the electrode 422 to protect the electrode 422 from mechanical wear. Thus, the electrode 422 is wrapped within the second layer 420.

[0088] The third layer 430 includes an electrode 432 sandwiched between two thin layers 431 and 433 of thermoplastic polyurethane (TPU). The electrode 432 may include a stretchable silver ink sheet. TPU is a positive triboelectric material. The top TPU layer 431 is in physical contact with the first ridged surface 413, and the bottom TPU layer 433 is in physical contact with the second ridged surface 423.

[0089] Figure 5 FIG. (a) shows an electronic device 400 according to an exemplary embodiment in cross-section. As previously described, the electronic device 400 includes a first silicone elastomer layer 410 and a second silicone elastomer layer 420 sandwiching a TPU layer 430. The silicone elastomer layers 410, 420 include a first ridged surface and a second ridged surface, the cross-section of which is generally sinusoidal, having peaks and valleys. The width 52 of the peaks (and valleys) and the height 51 of the peaks are indicated by arrows.

[0090] Figure 5 FIGS. (b) to (d) are graphs showing the open-circuit voltage, short-circuit charge, and short-circuit current, respectively, as a function of time after applying a cyclic compressive force of 30 N at a frequency of 1 Hz for six embodiments of the electronic device 400. These six embodiments correspond to peak heights 51 of 0 mm (i.e., flat), 0.25 mm, 0.5 mm, 1 mm, 2 mm, and 3 mm, respectively. Each embodiment has the same peak width 52 of 4 mm. Thus, the surface areas of the ridged surfaces provided by these six embodiments are 1600 mm 2 (flat), 1603 mm 2 (0.25 mm), 1614 mm 2 (0.5 mm), 1658 mm 2 (1 mm), 1831 mm 2 (2 mm), and 2120 mm 2(3 mm). For a peak height 51 of 1 mm, the maximum voltage, charge, and current are achieved because this configuration provides the maximum contact area between the first and second ridged surfaces and the TPU layer 430. For the peak width 52, increasing the peak height 51 beyond 1 mm does not significantly increase the contact area because the peak cannot further deform the TPU layer 430 (due to the stiffness of the TPU layer 430), and thus the peak itself begins to be in a compressed state. This is due to the viscoelasticity of the elastic material. In theory, the peaks on the silicone elastomer layers 410, 420 can exert pressure on the TPU layer 430 and push it up to a certain level, after which the stiffness of the TPU layer 430 causes an increase in the normal stress on the ridged surface, ultimately resulting in the compression of the viscoelastic Eco - flex peaks rather than further pushing the TPU layer 430. To verify this, a mechanical structure simulation was performed on the design structure of the electronic device 400.

[0091] The material properties of the silicone elastomer layers 410, 420 and the TPU layer 430 are given in Table 1.

[0092]

[0093] Table 1

[0094] To depict real - world situations, the 3D structures of the electronic devices 400 with different peak heights 52 were subjected to incremental compressive forces from 0 to 70 N.

[0095] The increase in the force applied to the electronic device 400 results in an increase in the electrical output. Similarly, the increase in the force applied to the contact area (i.e., the contact force) results in an increase in the electrical performance. To verify this theory, we derived the values of the contact area between the two triboelectric layers and the normal stress applied to the TPU layer 430 under a force of 30 N for all ridge sizes.

[0096] Figure 6 is a graph showing the relationship between the maximum contact area and the normal stress analyzed theoretically according to the exemplary embodiment and the peak height 51. It can be observed that the normal stress increases with the increase in the peak height 51, and the maximum contact area is 100% until the ridge size reaches 1 mm. Thereafter, the maximum contact area begins to decrease, which means that the maximum contact area is achieved at a peak height 51 of 1 mm.

[0097] Figure 7 is a graph showing the relationship between the contact force and the peak height 51 analyzed theoretically according to the exemplary embodiment. The maximum value of the contact force is achieved at a peak height 51 of 1 mm. As Figure 5 shown in (b) to (d) of

[0098] The responsiveness of the electronic device 400 to various forces is relevant to possible practical applications. Therefore, in order to study the relationship between an external mechanical load and the electrical output performance of the electronic device 400, the outputs (VOC, QSC, and ISC) of the above six embodiments were measured by applying a compressive force of 5 N to 70 N.

[0099] A dynamic mechanical customization device based on a custom linear motor was used to analyze the performance of the electronic device 400 by applying different ranges of compressive force and frequency. The electrical output performance under different compression conditions, including VOC, ISC, and QSC, was measured using an electrometer 6514 (Keithley instruments) and a low-noise preamplifier of an integrated digital fluorescence oscilloscope DPO-4104 (Tektronix Inc.).

[0100] Figure 8 (a) to (c) of are graphs showing examples of the output voltage, charge, and current of the six embodiments respectively as a function of the compressive force. The output amplitude of all embodiments can increase as the compressive force increases. This may be because a larger contact force increases the triboelectric surface charge density, thereby improving the output performance. In addition, after a compressive force of 30 N, VOC and QSC may start to saturate. This may be because a compressive force of 30 N is sufficient to push the maximum number of charges onto the contact surface. The output current can be a function of the force frequency because the current depends on the flow rate of the charges. Therefore, if the force frequency increases, the charge movement can also increase, which can result in an increase in the output current.

[0101] Figure 8 (d) of is a graph showing the output current of the six embodiments as a function of the force frequency. The substantially sinusoidal ridge arrangement of the embodiment with a surface area of 1658 mm 2 and a peak height of 1 mm can provide the highest current value at all different frequencies and forces used.

[0102] The above examples describe embodiments in which the ridged surface includes substantially sinusoidal ridges. It should be understood that this is not intended to be restrictive, and other ridge shapes can be used. For example, triangular ridge shapes and square ridge shapes can be used.

[0103] In some embodiments, the ridge shape and size can be designed to suit the specific use of the electronic device. In some embodiments, the ridge shape and size can be designed to suit a specific range of compressive forces expected to be applied to the electronic device.

[0104] Figure 9An example of a graph showing the relationship between the theoretically calculated maximum contact force and the applied force (compressive force) for various example embodiments having different ridge shapes. The example embodiments include a substantially sinusoidal ridge, a substantially triangular ridge, and a substantially square ridge (in cross-section). Figure 9 Indicates that embodiments including a square ridge can provide a higher contact force when the applied force is greater than about 30 N compared to embodiments having a sinusoidal or triangular ridge. However, at lower to medium applied forces (in the range of 10 N to 30 N), embodiments including a sinusoidal ridge can provide a higher contact force than embodiments including a square ridge. At all applied force values, embodiments including a triangular ridge can provide a lower contact force than embodiments including a sinusoidal or square ridge. Thus, in some embodiments, a square ridge may be preferred where the device may be subjected to greater applied forces. Similarly, in some embodiments, a sinusoidal ridge may be preferred where the device may be subjected to lower and medium applied forces (e.g., in biomedical applications where the device is subjected to low pressure from the body).

[0105] Figure 10 An example of a graph showing the relationship between the theoretically estimated ridge deformation and the contact force for various example embodiments having different ridge shapes. The results show that ridges formed as triangles can deform at a faster rate than ridges formed as sinusoids or squares. Thus, ridges formed as squares and sinusoids can provide a slower deformation rate. Additionally, in some embodiments, for all applied forces, the deformation of ridges formed as sinusoids can be less than the deformation of ridges formed as squares. In some embodiments, a sinusoidal ridge can provide a greater contact force than an embodiment including a ridge formed as a square while maintaining the integrity of the structure. Figure 10 Indicates that generally, the deformation rate of embodiments including ridges formed as sinusoids can be lower than embodiments including ridges formed as triangles or squares. Thus, embodiments including sinusoidal ridges can provide improved structural integrity compared to embodiments including ridges formed as triangles or squares.

[0106] In some embodiments, the electronic device can be the same as or similar to the electronic device 400 associated with Figure 5 and can include a sinusoidally shaped ridge with a peak height 51 of 1 mm. Figure 11 Examples of output signals from this example electronic device are shown in (a) to (d) of

[0107] Figure 11 (a) of shows a graph of the output voltage of an example electronic device as a function of load resistance according to an example embodiment. The voltage (V load ) can increase as the resistance increases starting from 1 MΩ and reaches a maximum value (88 V) at 10 GΩ, while the current (Iload ) shows an opposite trend, reaching a maximum value at 10KΩ. The two quantities may cross each other at about 100MΩ, indicating that this value is approximately the internal resistance of the electronic device. Since this electronic device has a high internal resistance, it can be used as a current source.

[0108] Figure 11 (b) is a graph showing the output power density of an example electronic device as a function of load resistance according to an example embodiment. The power density was studied by connecting the example device in series with an external variable resistor (10KΩ to 10GΩ) and testing at 30N and a constant frequency (1Hz). By using the formula P = I 2 R (where I is the output current at the load resistor) calculates the output power density. Figure 11 The maximum measured output current shown in (b) is 360mW / m at 100MΩ 2 In some embodiments, 100 MΩ may be considered an approximation of the internal resistance of an example electronic device.

[0109] Figure 11 (c) is a graph showing the output power density as a function of resistance for force frequencies of 1 Hz, 5 Hz, and 7 Hz according to an example embodiment. The output power density can be increased by increasing the cyclic frequency of the applied force (360 mW / m at 1 Hz, 5 Hz, and 7 Hz, respectively). 2 、~406mW / m 2 and 490mW / m 2 ).

[0110] Figure 11 (d) is a graph showing the output voltage stability of the electronic device 400 as a function of the number of force cycles according to an example embodiment. The voltage stability was evaluated by applying a compressive force of 30N at 1 Hz and performing 1200 cycles. It was observed that the output voltage (V OC ), indicating the practical value of the electronic device 400 in long-term cycle applications.

[0111] The power supply capability of the electronic device 400 was analyzed by applying a compressive force to power a commercial light emitting diode (LED) and a calculator. To power the LEDs, the LEDs were simply connected in series with each other and connected to the electronic device. To power the calculator, the output of the electronic device was connected to a bridge rectifier IC. Two 47μF capacitors were connected in series to store the rectified output. The calculator was then connected in parallel with the capacitors to power the calculator.

[0112] Figure 12An electronic device according to an exemplary embodiment is shown. The electronic device is used to power a plurality of commercially available LEDs connected in series. After the electronic device is subjected to a compressive force of 30 N at 5 Hz, the LEDs emit light.

[0113] Figure 13 An electronic device according to an exemplary embodiment is shown. The electronic device is used to power a commercially available digital calculator using a compressive force of 30 N and 5 Hz. The output of the electronic device is first rectified and then used to charge a capacitor (23.5 μF) to 2.2 V. The charged capacitor is then used to power the calculator.

[0114] Data acquisition for the respiratory monitor application was performed as follows: using a DAQ-6510 (Keithley Instruments) and integrating it with a custom application developed on the LabView platform (National Instruments Corp.). For the respiratory monitor, a 4x4 cm 2 electronic device is encapsulated in a 3D printed box, which is fixed to the lower chest area. Then, a respiratory wave signal from the electronic device is acquired through a LabView-based program.

[0115] Figure 14 (a) of shows an electronic device according to an exemplary embodiment. The electronic device is used for a real-time respiratory monitoring band. A 3D printed housing and a fabric baseband are used to fix the electronic device against the lower chest area.

[0116] Figure 14 (b) of shows the output voltage of an exemplary electronic device as a function of time according to an exemplary embodiment. The exemplary electronic device is capable of determining different respiratory phases, for example, tachypnea (hyperventilation) condition, apnea (no breathing) condition, and eupnea (normal breathing) condition.

[0117] Data acquisition for the pulse detector and gait analysis applications was performed as follows: using a USB-DAQ6343 (National Instruments) and integrating it with a custom application developed on the LabView platform (National Instruments). For the implementation of the pulse sensor, a 3D printed box is used to place the electronic device therein and strap it to the wrist (as Figure 15 shown). Then a pulse signal from the wrist-strapped electronic device is acquired through a LabView-based program. The program processes the acquired signal in real time using a peak detection module. For the gait analysis application, seven embodiments of an electronic device with dimensions of 1.6 × 1.6 cm 2 are placed in a custom-made sole made of laser-cut flexible corkboard (as Figure 16as shown). The intensity plotting module based on LabView is used to record and plot the real-time activation and deactivation of multiple electronic devices.

[0118] Figure 15 (a) of shows an electronic device used as a pulse monitoring force sensor according to an exemplary embodiment. The electronic device is sized to measure 12x12 mm 2 and is used as a real-time pulse count monitor. In addition, a 3D printed housing and a strap are used to fix the electronic device to the wrist.

[0119] Figure 15 (b) of shows an example of the sensed signal from the electronic device of Figure 15 (a). The sensed signal shows the user's pulse rate.

[0120] Figure 16 (a) of shows an electronic device used as a pressure sensing sole for gait analysis according to an exemplary embodiment. A plurality of electronic devices (S1 to S7) are arranged in an array in the sole for real-time gait monitoring applications. The electronic device allows real-time recording of the pressure map of the human foot.

[0121] Figure 16 (b) of shows an example of the sensed signal from the electronic device of Figure 16 (a). The sensed signal can be used to monitor the pressure distribution on the sole when the user steps on the sole.

[0122] Figure 16 (c) of shows an example of the sensed signal from the electronic device of Figure 16 (a). An example of the sensed signal from the device when the user is running is shown. An example of the sensed signal from the device when the user is walking is also shown. Since the exemplary sensed signals are different from each other, the sensed signals can be used to monitor the user's movement.

[0123] In some embodiments, the electronic device can be used for different biomedical applications, including patient body movement monitoring, monitoring of dementia patients by observing environmental changes and the patient's daily physical activities, etc.

[0124] In some embodiments, a silicon elastomer with a ridged surface and a TPU film are used as a negative triboelectric material and a positive triboelectric material, respectively.

[0125] Figure 17 shows a method of manufacturing a silicon elastomer layer with a ridged surface according to an exemplary embodiment. In order to create a ridged surface on the silicon elastomer, first, an inverse ridged pattern mold is developed using 3D printing technology. These molds with different ridge sizes are made of polylactic acid (PLA) in 4x4 cm 2Fabricated on an area of. Subsequently, a mixture of equal volumes of Component A and Component B of Ecoflex 00-30 (Smooth-on Inc.) was prepared and poured onto the 3D printing mold, and then cured in an oven at 60 °C for 4 hours. After the curing process, silver (Ag) ink (DuPont PE874; Insulectro Printed Electronics) was deposited on its surface via a stencil of 3.6 x 3.6 cm 2 Subsequently, another elastomer layer was coated on top and used as a protective layer for the silver electrode, and then cured at 60 °C for 4 hours. The entire stack consisted of a ridged elastomer and a silver electrode, and then the protective layer was peeled off from the 3D printing mold. Further, such an entire elastomer ridged stack was heated in an oven at 120 °C for 20 minutes to fully cure the silver ink.

[0126] Figure 18 Shows a method of manufacturing a TPU layer according to an exemplary embodiment. Silver ink was printed onto a commercially available TPU layer (Platilon U073 Covestro Ag.; thickness 100 μm) with an area of 4×4 cm 2 as an electrode by the doctor blade method, and then cured at 120 °C for 20 minutes. Subsequently, another TPU layer was placed and laminated on top of the TPU / Ag, and a uniform double-sided TPU layer with a silver electrode in the middle was obtained through a hot pressing technique.

[0127] Finally, the fabricated TPU / Ag / TPU stack was further sandwiched between two elastomer ridged stacks to realize an electronic device, such as Figure 3 shown.

Claims

1. An electronic device, comprising: a first layer and a second layer, each layer including a first triboelectric material, wherein the first layer and the second layer respectively include a first ridged surface and a second ridged surface, a third layer sandwiched between the first ridged surface and the second ridged surface and in physical contact with the first ridged surface and the second ridged surface, wherein the third layer is elastically deformable and includes a second triboelectric material, wherein the first triboelectric material has a charge type opposite to that of the second triboelectric material; wherein, in a compressed state, the first ridged surface and the second ridged surface are adapted to cooperatively deform the third layer; wherein, in a released state, the first ridged surface and the second ridged surface provide a spacing between the first ridged surface and the third layer and between the second ridged surface and the third layer; and wherein each layer further includes an electrode.

2. The electronic device according to claim 1, further comprising an output terminal connected to the electrode.

3. The electronic device according to claim 2, wherein, The output terminal is configured to provide a voltage pulse in response to a transition from the released state to the compressed state or from the compressed state to the released state.

4. The electronic device according to any one of claims 1 to 3, wherein, One of the first triboelectric material and the second triboelectric material is of a negative charge type, and the other of the first triboelectric material and the second triboelectric material is of a positive charge type.

5. The electronic device according to claim 4, wherein, The triboelectric material of the negative charge type includes a silicone elastomer.

6. The electronic device according to claim 4 or claim 5, wherein, The triboelectric material of the positive charge type includes a thermoplastic polyurethane.

7. The electronic device according to any one of the preceding claims, wherein, The first layer and the second layer further include planes adjacent to their respective ridged surfaces.

8. The electronic device according to claim 7, wherein, The electrodes of the first layer and the second layer are respectively disposed on the planes of the first layer and the second layer.

9. The electronic device according to claim 8, further comprising a fourth layer and a fifth layer arranged to cover the electrodes of the first layer and the second layer.

10. The electronic device according to any one of the preceding claims, wherein, The electrode of the third layer is disposed within the third layer.

11. The electronic device according to any one of the preceding claims, wherein, The electrode includes a stretchable material.

12. The electronic device according to claim 11, wherein, The stretchable material is silver ink.

13. The electronic device according to any one of the preceding claims, wherein, Each of the first ridged surface and the second ridged surface includes a ridge defined by protrusions and depressions.

14. The electronic device according to claim 13, wherein, In the compressed state, the protrusions of the first ridged surface are capable of accommodating the depressions of the second ridged surface.

15. The electronic device according to claim 13 or 14, wherein, The protrusions and the depressions are sinusoidal peaks and valleys, triangular peaks and valleys, or square peaks and valleys in a given plane.

16. The electronic device according to any one of the preceding claims, wherein, The electronic device is a force sensor or forms part of the force sensor.

17. A method: A first layer and a second layer are provided, each layer including a first triboelectric material, wherein, The first layer and the second layer respectively include a first ridged surface and a second ridged surface, providing a third layer, the third layer being elastically deformable and including a second triboelectric material, wherein the first triboelectric material has a charge type opposite to that of the second triboelectric material; providing an electrode on or within each layer; The third layer is sandwiched between the first ridged surface and the second ridged surface and is in physical contact with the first ridged surface and the second ridged surface, so that in a compressed state, the first ridged surface and the second ridged surface cooperatively deform the third layer, and so that in a released state, the first ridged surface and the second ridged surface provide spacing between the first ridged surface and the third layer and between the second ridged surface and the third layer.

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