KR20160105161A - Transparent and Stretchable Electrotactile Stimulator and Process for Preparing the Same - Google Patents

Abstract

The present invention relates to a transparent and flexible electric stimulator, and to a manufacturing method thereof. The electric stimulator comprises: a patterned first protection layer; a patterned electrode layer formed near the patterned first protection layer; a patterned second protection layer formed near the patterned electrode layer; and an adhesive layer formed near the patterned second protection layer.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a transparent and stretchable electric stimulator,

The present invention relates to a transparent stretchable electric stimulator and a method of manufacturing the same. More particularly, the present invention relates to a patterned first protective layer; A patterned electrode layer formed adjacent to the patterned first passivation layer; A patterned second protective layer formed adjacent to the patterned electrode layer; And an adhesive layer formed adjacent to the patterned second protective layer, and a method of making the same.

A wearable interactive human machine interface (iHMI) system is particularly well suited for use with smart glasses (Feng, S., et al . Immunochromatographic diagnostic assay using google glass, ACS Nano 8, 3069-3079 (2014)) and a timepiece (Wile, DJ, Ranawaya, R. , Kiss, ZHT Smart watch accelerometry for analysis and diagnosis of tremor, J. Neurosci. Methods 230, 1-4 (2014)) Has recently been attracting attention with the recent development of wearable electronic devices.

Wearable devices incorporating robust sensors and actuators offer high performance and practicality, but inconveniences arise from mechanical incompatibility between the human body and bulky rigid devices (Kim, D.-H., et al . Epidermal Electronics. Science 333 , 838-843 (2011) (Son, D., et al . Multifunctional wearable devices for diagnosis and therapy of movement disorders. Nat . Nanotech . 9 , 397-404 (2014) (Jeong, J.-W., et al . Materials and optimized designs for human-machine interfaces via epidermal electronics. Adv. Mater . 25 , 68396846 (2013)); Due to the design irreversibility of rugged electronics (Reuss, RH, et al . Macroelectronics: perspectives on technology and applications, Proc. IEEE , 93 , 1239-1256 (2005)), An unnatural appearance of the wearer due to design misalignment; And signal artefacts due to the nonconformal attachment of the robust sensor to the human body (Kim, D.-H., et al . Epidermal Electronics. Science 333 , 838-843 (2011) (Son, D., et al . Multifunctional wearable devices for diagnosis and therapy of movement disorders. Nat . Nanotech . 9 , 397-404 (2014) (Jeong, J.-W., et al . Materials and optimized designs for human-machine interfaces via epidermal electronics. Adv . Mater . 25 , 68396846 (2013)).

Therefore, there is a need for a new device that can be conformally laminated to human skin to have a natural appearance and a high signal-to-noise ratio (SNR).

The adoption of a flexible and stretchable design and subsequent reduction in thickness and weight of the device is an important goal with respect to wearable electronic device design.

Recently, a flexible inorganic electronic device (Kim, D.-H., et al . Epidermal Electronics. Science 333 , 838-843 (2011) (Son, D., et al . Multifunctional wearable devices for diagnosis and therapy of movement disorders. Nat . Nanotech . 9 , 397-404 (2014) (Webb, RC, et al . Ultrathin conformal devices for precise and continuous thermal characterization of human skin. Nat . Mater . 12 , 938-944 (2013)), ultra-light and lightweight organic sensors (Someya, T., et al . Conformable, flexible, large-area networks of pressure and thermal sensors with organic transistor active matrixes. Proc . Natl . Acad . Sci . USA 102, 12321-12325 (2005) ( Sekitani, T., Zchieschang, U., Klauk, H., Someya, T. Flexible organic transistors and circuits with extreme bending stability. Nat. Mater. 9, 1015-1022 (2010 ), flexible electronics skin (Takei, K., et al. Nanowire active-matrix circuitry for low-voltage artificial skin macroscale. Nat. Mater. 9, 821-826 (2010) (Wang, C., et al . User-interactive electronic skin for instantaneous pressure visualization. Nat . Mater . 12, 899-904 (2013), and highly sensitive and flexible mechanical sensor (Mannsfeld, SCB, et al. Highly sensitive flexible pressure sensors with microstructured rubber dielectric layers. Nat. Mater. 9, 859-864 (2010)) (Lipomi, DJ, meat al . Skin-like pressure and strain sensors based on transparent elastic films of carbon nanotubes. Nat . Nanotech . 6 , 788-792 (2011)) (Jung, S., et al . Reverse-Micelle-Induced Porous Pressure-Sensitive Rubber for Wearable HumanMachine Interfaces. Adv Mater. Early View (2014)) (Gong, S, et al . A wearable and highly sensitive pressure sensor with ultrathin gold nanowires. Nat. Comm, 5 , 3132 (2014)).

The ultra-thin, deformable design allows accurate data collection from the human body with minimal signal noise. However, these previously reported devices are made of opaque semiconductors and metals and appear different from human skin. In addition, most of these sensors consume large amounts of power and thus require large power supplies (Kim, D.-H., et al., Epidermal Electronics Science 333 , 838-843 (2011) D., et al . Multifunctional wearable devices for diagnosis and therapy of movement disorders. Nat . Nanotech . 9 , 397-404 (2014) (Jeong, J.-W., et al . Materials and optimized designs for human-machine interfaces via epidermal electronics. Adv. Mater . 25 , 68396846 (2013)).

Transparent electronic materials can make the wearable device invisible, creating a natural look and enhanced aesthetics.

For example, carbon-based nanomaterials (Grafin (Kim, KS , et al . Large-scale pattern growth of graphene films for stretchable transparent electrodes. Nature 457 , 706-710 (2009)) and carbon nanotubes (Wu, Z. , et al . Transparent, conductive carbon nanotube films. Science , Vol. 87 , 1273-1276 (2004)) and metal nanowires (NW) (Hu, L., Kim, HS, Lee, J.-Y., Peumans, P., Cui, Y., meat al . Scalable coatings and properties of transparent, flexible, silver nanowire electrodes. ACS Nano 4 , 2955-2963 (2010)) and gold nanowires (Moraq, A., Ezersky, V., Froumin, N., Moqiliansky, D., Jelinek, R., Transparent, conductive gold nanowire networks assembled from soluble Au thiocyanate. Chem. Comm ., 49 , 8552-8554 (2013))) have been intensively studied.

Such transparent nanomaterials can be used in flexible electronic devices because they dramatically reduce the bending strength of nanoscale structures (Son, D., et al . Multifunctional wearable devices for diagnosis and therapy of movement disorders. Nat . Nanotech . 9 , 397-404 (2014)) (Rogers, J., Lagally, MG, Nuzzo, RG, Synthesis, Assembly and Applications of Semiconductor Nanomembranes, Nature 477 , 45-53 (2011)).

On the other hand, self-powered mechanical sensors based on piezoelectric materials can reduce the power dissipation of electronic systems (Xu, S., et al., Self-powered nanowire devices, 5 , 366-373 2010).

Poly (vinylidene chloride) (Lee, M. , et al . A hybrid piezoelectric structure for wearable nanogenerators. Adv . Mater . 24, 1759-1764 (2012)) ( Persano, L., et al. High performance piezoelectric devices based on aligned arrays of nanofibers of poly (vinylidenefluoride-co-trifluoroethylene). Nat. Comm. 4, 1633 (2013)) and Polylactic acid (PLA) (Yoshida, T. , et al . In this paper, we propose a new type of chiral polymer film. Jpn . J. Appl . Phys . 50 , 09ND13-1-09ND13-5 (2011)), and zinc oxide (Wang, ZL, Song, J., Piezoelectric nanogenerators based on zinc oxide nanowire arrays. Science 312 , 242-246 (2006) And lead zirconate titanate (Qi, Y. , et al . Enhanced piezoelectricity and stretchability in energy harvesting devices fabricated from buckled PZT ribbons. Nano Lett . 11 , 1331-1336 (2011)), a wide variety of piezoelectric materials have been studied.

The present inventors have found that by observing human motion, converting recorded data into a signal for machine control, delivering a triggering signal to the machine, and transmitting feedback information from the machine to an operator via an electrotactile device A stimulator was developed to transmit the stimulus.

A basic object of the present invention is to provide a patterned first protective layer; A patterned electrode layer formed adjacent to the patterned first passivation layer; A patterned second protective layer formed adjacent to the patterned electrode layer; And an adhesive layer formed adjacent to the patterned second protective layer.

Still another object of the present invention is to provide a method of manufacturing a semiconductor device, comprising: (i) forming a first protective layer on a silicon substrate coated with nickel; (ii) patterning the first passivation layer; (iii) transferring the graphene layer onto the patterned first protective layer; (iv) coating the silver nanowire dispersion on the graphene layer and then heating; (v) transferring the graphene onto the dried silver nanowire layer; (vi) patterning the graphene / silver nanowire / graphene multilayer; (vii) forming a second protective layer over the patterned graphene / silver nanowire / graphene multilayer; (viii) patterning the second passivation layer; (ix) coating polymethylmethacrylate on the patterned second passivation layer; (x) removing the nickel layer using an etchant and separating the silicon wafer to produce an electric stimulator; (xi) transferring the electric stimulator to polydimethylsiloxane; And (xii) removing the polymethylmethacrylate layer. ≪ Desc / Clms Page number 2 >

The basic object of the present invention described above is to provide a patterned first protective layer; A patterned electrode layer formed adjacent to the patterned first passivation layer; A patterned second protective layer formed adjacent to the patterned electrode layer; And an adhesive layer formed adjacent to the patterned second protective layer. ≪ RTI ID = 0.0 > [0002] < / RTI >

In the transparent and stretchable electrical stimulator of the present invention, the patterned first protective layer may be an epoxy resin (e.g. SU8, Microchem) or benzocyclobutene (BCB). In addition, the thickness of the patterned first protective layer may be 100 nm to 100 탆.

In the transparent and stretchable electrical stimulator of the present invention, the patterned electrode layer may be graphene, single wall carbon nanotubes (SWNTs) or silver nanowires (AgNW). Preferably, the patterned electrode layer may be a graphene / silver nanowire / graphene multilayer. The silver nanowire serves to increase the conductivity of graphene. Further, the thickness of the patterned conductive layer may be 1 nm to 100 nm.

In the transparent and stretchable electrical stimulator of the present invention, the patterned second protective layer may be an epoxy resin (e.g., SU8) or benzocyclobutene. Also, the thickness of the patterned second protective layer may be 100 nm to 100 탆.

In the transparent and stretchable electrical stimulator of the present invention, the adhesion layer may be polydimethylsiloxane. Further, the thickness of the adhesion layer may be from 1 μm to 100 μm.

Still another object of the present invention is to provide a method of manufacturing a semiconductor device, comprising: (i) forming a first protective layer on a silicon substrate coated with nickel; (ii) patterning the first passivation layer; (iii) transferring the graphene layer onto the patterned first protective layer; (iv) coating the silver nanowire dispersion on the graphene layer and then heating; (v) transferring the graphene onto the dried silver nanowire layer; (vi) patterning the graphene / silver nanowire / graphene multilayer; (vii) forming a second protective layer over the patterned graphene / silver nanowire / graphene multilayer; (viii) patterning the second passivation layer; (ix) coating polymethylmethacrylate on the patterned second passivation layer; (x) removing the nickel layer using an etchant and separating the silicon wafer to produce an electric stimulator; (xi) transferring the electric stimulator to polydimethylsiloxane; And (xii) removing the polymethylmethacrylate layer. ≪ Desc / Clms Page number 6 >

In the transparent and stretchable electric stimulator manufacturing method of the present invention, the patterning of each layer can be performed by photolithography.

In the transparent and stretchable electric stimulator manufacturing method of the present invention, the first protective layer may be an epoxy resin (for example, SU8) or benzocyclobutene. In addition, the thickness of the first protective layer may be 100 nm to 100 m.

In the method of the present invention for producing a transparent and stretchable electric stimulator, the thickness of the graphene / silver nanowire / graphene multilayer may be between 1 nm and 100 nm.

In the transparent and stretchable electrical stimulator manufacturing method of the present invention, the second protective layer may be an epoxy resin (e.g., SU8) or benzocyclobutene. The thickness of the second protective layer may be 100 nm to 100 m.

In the method of the present invention for producing a transparent and stretchable electric stimulator, the skin attachment film may be polydimethylsiloxane. Further, the thickness of the skin attachment film may be from 1 μm to 100 μm.

The transparent and stretchable electrical stimulator of the present invention can be applied to an interactive human machine interface since it can be conformally attached to human skin and does not fall off well. In addition, due to the transparency of the electric stimulator of the present invention, the wearer can be esthetically improved when worn.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a method of manufacturing a transparent electric stimulator of the present invention. FIG.
Figure 2a is a photograph of a transparent electrical stimulator of the present invention conformally contacting an upper part of a human wrist, and Figure 2b is a photograph of a part of a transparent electrical stimulator of the present invention being peeled off.
3 is a developed view of a patterned graphene (GP) heterostructure used in the electrical stimulator of the present invention.
FIG. 4 is a scanning electron microscope (SEM) photograph (epoxies: blue, GP / AgNW / GP: pink) obtained by coloring a cross section of a patterned graphene (GP) heterostructure used in the electric stimulator of the present invention.
5 is the transmittance in the visible light region of the electric stimulator (blue) of the present invention.
Figure 6 shows the sheet resistance of the initial (red), gold-doped (green), and silver nanowire (AgNW) -coated (blue) GP heterostructures. 6 is an SEM photograph of the GP coated with the silver nanowire.
Fig. 7 shows human motion (left), its enlarged view (middle) with its corresponding bending radius, and its bending motion at each bend radius (right).
Figure 8 shows the change in resistance per unit length of the initial (red), gold-doped (green), and silver nanowire-coated (blue) GP heterostructures, and the resistance varies inversely with the bending radius.
9 is a SEM photograph of the surface of the ITO film on the PET layer after bending the structure.
10 shows a finite element analysis showing the strain distribution of the GP heterostructure when the bending radius R is ∞ (FIG. 10A), 1.3 cm (FIG. 10B), 0.52 cm (FIG. 10C) and 0.38 cm (FEA) results and corresponding photographs of the bent heterostructure.
Figure 11 is a photograph of a transparent electrical stimulator of the present invention attached to pig skin.
Figure 12 is an illustration of an experimental apparatus for performing electrical stimulation and recording using the electrical stimulator of the present invention.
Fig. 13 shows the measured voltages from the recorders (2), (3) and (4) shown in Fig.
Figure 14 shows the recorded voltage as a function of the number of skin layers for different stimulation currents.
Figure 15 plots the minimum stimulation voltage needed to be sensed as a function of frequency.
16 is FEA (Finite Element Analysis) results of the three-dimensional potential distribution of the skin in the case of direct stimulation using the electric stimulator of the present invention.
Figure 17 is a photograph of the pristine (left) and elongated (right) states of the transparent and stretchable electrical stimulator of the present invention.
Figure 18 shows the resistance of the serpentine GP electrode as a function of applied strain.
Figure 19 is an FEA result showing the strain distribution on an electric stimulator / recorder under 30% stretching.

Hereinafter, the present invention will be described in more detail with reference to the following examples or drawings. It is to be understood, however, that the following description of the embodiments or drawings is intended to illustrate specific embodiments of the invention and is not intended to be exhaustive or to limit the scope of the invention to the precise forms disclosed.

Example  1. Silver Of nanowires (AgNW)  synthesis

5 ml of ethylene glycol (EG, JUNSEI, Japan) was poured into a 50 ml vial and heated in an oil bath (153 ° C) with stirring at 260 rpm to synthesize the nanowires. After heating for 30 minutes, 40 μL of 4 mM copper chloride (CuCl ₂ .2H ₂ O, 99%, DAEJUNG, Korea) solution dissolved in EG was added with heating for 15 minutes. 1.5 ml of 0.094 M silver nitrate (AgNO ₃ 99% +, Strem Chemicals, Inc.) dissolved in 1.5 mL of 0.147 M poly (vinylpyrrolidone) (PVP, avg. MW 55000, Aldrich, USA) and EG. , USA). After the injection, the reaction was allowed to proceed for 1 hour. Next, the silver nanowire solution was centrifuged and redispersed in acetone three times. Finally, the silver nanowires were dried and dispersed in ethanol to 1 wt%.

Example  2. Grapina  synthesis

Graphene was synthesized by chemical vapor deposition (CDV) on 25 μm copper foil (Alfa Aesar, USA). The copper foil was annealed at 1000 占 폚 for 1 hour with a constant hydrogen flow (8 sccm) and then methane gas (20 sccm) was inserted for 30 minutes. Subsequently, under a hydrogen atmosphere, the temperature of the chamber was rapidly cooled to room temperature. After the PMMA (A4, 495, Microchem, USA) was spin-coated, the graphene layer synthesized on the copper foil was immersed in a copper etching solution to etch copper, and the graphene / PMMA layer was floated. The separated graphene layer was washed with deionized water to remove the residual etchant.

Example  3. Transparent Wearable  Manufacture of electric stimulator

A schematic description of the manufacturing method is shown in Fig. The method comprises the steps of: Starting from the wafer plating (Cr / Ni, 7 nm / 70 nm thickness), the substrate was then spin-coated with a negative epoxy (SU8, Microchem, USA). An epoxy pattern was formed by photolithography. Then, the graphene layer was transferred to the substrate. Next, the silver nanowire dispersion was spin-coated on the graphene layer at 3000 rpm for 30 seconds and baked at 200 DEG C for 5 minutes. Finally, a second graphene layer was transferred to the graphene layer containing the silver nanowires and separated using reactive ion etching (O ₂ plasma, 150 sccm, chamber pressure of 150 mTorr, high frequency power 100 W, etch time 20 seconds). The upper epoxy layer was patterned through photolithography. PMMA layer was spin-coated on top; This layer served as a supporting layer. A nickel etchant was used to remove the nickel film serving as a sacrificial layer. After the etching treatment was completed, the stimulator was transferred onto a PDMS / PVA film. Finally, the PMMA layer of the device was removed with an acetone solution.

Example  4. Optical, electrical and mechanical properties

Figure 2 shows an electrical stimulator (Figure 2a) and a photograph partially separated (Figure 2b) with respect to the electrical stimulator. The device's ultra-thin, lightweight and stretch allows confomal intergration with the human skin and is considerably comfortable. Also, due to the high transparency, the device is still difficult to notice after partial delamination. The invisible, skin-conforming device using a transparent material has a natural, aesthetically pleasing appearance and assures privacy of the individual.

The structural design of the device and the properties of the material used are shown in an enlarged view of the patterned conductive graphene (GP) heterostructure used in the electrical stimulator (FIG. 3). The electrical stimulator consists of a conductive graphene heterostructure (Fig. 4), i.e. a network of silver nanowires sandwiched between doped graphene layers, which leads to better conductivity and charge-injection into the skin . The silver nanowires were synthesized in ethylene glycol using a copper seed and a poly (vinyl pyrrolidone) ligand. Figure 4 shows a scanning electron microscope (SEM) photograph of a cross section of a conductive graphene heterostructure used in a stimulator. The epoxy and graphene / AgNW / graphene layers of the stimulator were blue and pink, respectively.

The transmittance of an electric stimulator made of GP / AgNW / GP was measured in the visible light region (FIG. 5, 380 to 780 nm); The electrical stimulator exhibits high transparency. Indium tin oxide (ITO) electrodes are widely used as transparent electrodes. However, in the pristine state, graphene has sheet resistance higher than that of ITO, and therefore graphene must be deformed in order to improve the conductivity. Thus, conductive graphene heterostructures comprising silver nanowires, comprised of multi-layer graphene doped with gold chloride, are used. Figure 6 shows the sheet resistance measured for an initial state (696.5? /?), Gold doping (354.5? /?) And silver nanowire coating (98.8? /?) For a graphene electrode; The measured values indicate that the conductivity of graphene can be successfully increased by doping. The inset of FIG. 6 shows a SEM photograph of silver nanowire coated graphene.

One of the advantages of the graphene heterostructure for ITO is the extremely high mechanical deformability. The graphene heterostructure and the ITO film are bent at different bending radii using a bending step. The bending radius is measured based on the position of the bent human wrist (Fig. 7). In the bending test, it was confirmed that the graphene heterostructure was maintained at a high electrical conductivity even in an extremely bent state, whereas the ITO film showed a sharp increase in sheet resistance (FIG. 8). As shown in the SEM image of the ITO film (FIG. 9), the increase in resistance of the ITO is due to the cracks formed when bent. On the other hand, cracks are not observed in the graphene heterostructure.

An analysis based on theoretical mechanics confirms this observation. Strain distributions for different bending radii of the graphene heterostructure and ITO films were obtained by FEA; Photographs of the experiment are shown in Figs. 10E to 10H. The red dotted box corresponds to the analysis area of FEA. The FEA results show that the local strain distributions of the graphene heterostructure and ITO film at the same bending radius are not much different. However, critical strains that cause mechanical cracks in the ITO film (<1%) and graphene heterostructures (> 5%) are different. The addition of silver nanowires further improves the mechanical strength of the graphene heterostructure. Thus, the conductive graphene heterostructure maintains its inherent electrical properties even during the dynamic operation of the human body.

Example  5. Electricity Stimulator  conductivity GP Heterostructure

Information transmitted from the outside can be transmitted to the human operator through the electric stimulator. In addition, the electrical stimulator must be transparent and stretchable, thereby aesthetically pleasing, and is also conformally integrated into the human skin for effective charge injection. Figure 1 shows a schematic view of the stimulator manufacturing method. The above process starts with deposition of a sacrificial layer (Cr / Ni, 7 nm / 70 nm) patterned with a transparent epoxy (SU8, Microchem, USA). The GP / AgNW / GP multilayer is then transferred onto the epoxy layer, patterned and covered in an additional epoxy. Next, the whole device is transferred-printed onto a PDMS / polyvinyl alcohol (PVA) substrate. Finally, the electrical stimulator is delivered to the skin by dissolving the PVA layer in water.

Pork skin was used to determine the charge injection characteristics of the electrical stimulator. Electric stimulators and recording electrodes were placed at the upper and lower sides of the pig skin piece, respectively, at an equal angle (Fig. 11). Figure 12 shows the experimental setting and the distance between the electrical stimulator and the recording electrode. The distance between the electrodes increases in the following order: (1) - (2) <(1) - (3) <(1) - (4). The amplitude of the recorded voltage between the two electrodes decreased with decreasing distance (Fig. 13). Also, as the skin thickness increased, the recording voltage decreased (FIG. 14). A stimulus voltage greater than the threshold that can be perceived must be applied; The voltage depends on the thickness of the skin (Delmas, P., Hao, J., Rodat-Despoix, L., Molecular mechanisms of mechanotransduction in mammalian sensory neurons. Nat . Neurosci . 12 , 139-153 (2011)). Figure 15 shows that the sensing voltage is a plot as a function of the stimulation frequency and the minimum sensing voltage is inversely proportional to the frequency (Ying, M., meat al . Silicon nanomembranes for fingertip electronics. Nanotechnology . 23 , 1-7 (2012)). The spatial distribution of the mechanoreceptors that can be successfully stimulated can be estimated using FEA (Fig. 16). Even after the stimulator is elongated to greater than about 30% (Figure 17) (Son, D., et al . Multifunctional wearable devices for diagnosis and therapy of movement disorders. Nat . Nanotech . 9 , 397-404 (2014)) and stable charge injection (Fig. 18). Figure 19 shows the strain distribution on the stimulator when stretched.

Claims (18)

A first patterned protective layer; A patterned electrode layer formed adjacent to the patterned first passivation layer; A patterned second protective layer formed adjacent to the patterned electrode layer; And an adhesive layer formed adjacent the patterned second protective layer. &Lt; Desc / Clms Page number 19 &gt; 2. The transparent, stretchable electrical stimulator of claim 1, wherein the patterned first passivation layer is an epoxy resin or benzocyclobutene. 2. The transparent, stretchable electrical stimulator of claim 1, wherein the thickness of the patterned first passivation layer is 100 nm to 100 [mu] m. 3. The transparent, stretchable electrical stimulator of claim 1, wherein the patterned electrode layer is selected from the group consisting of graphene, single-wall carbon nanotubes, and silver nanowires. 6. The transparent, stretchable electrical stimulator of claim 1, wherein the patterned electrode layer is a graphene / silver nanowire / graphene multilayer. 2. The transparent and stretchable electrical stimulator of claim 1, wherein the patterned conductive layer has a thickness of 1 nm to 100 nm. The transparent, stretchable electrical stimulator of claim 1, wherein the patterned second protective layer is an epoxy resin or benzocyclobutene. 2. The transparent, stretchable electrical stimulator of claim 1, wherein the thickness of the patterned second protective layer is 100 nm to 100 m. 2. The transparent, stretchable electrical stimulator of claim 1, wherein the adhesive layer is polydimethylsiloxane. 2. The transparent, stretchable electrical stimulator according to claim 1, wherein the thickness of the adhesive layer is between 1 [mu] m and 100 [mu] m. (i) forming a first protective layer on a silicon substrate coated with nickel;
(ii) patterning the first passivation layer;
(iii) transferring the graphene layer onto the patterned first protective layer;
(iv) coating the silver nanowire dispersion on the graphene layer and then heating;
(v) transferring the graphene onto the dried silver nanowire layer;
(vi) patterning the graphene / silver nanowire / graphene multilayer;
(vii) forming a second protective layer over the patterned graphene / silver nanowire / graphene multilayer;
(viii) patterning the second passivation layer;
(ix) coating polymethylmethacrylate on the patterned second passivation layer;
(x) removing the nickel layer using an etchant and separating the silicon wafer to produce an electric stimulator;
(xi) transferring the electric stimulator to a skin attachment film; And
(xii) removing the polymethylmethacrylate layer.
A method for manufacturing a transparent and stretchable electrical stimulator. 12. The method of claim 11, wherein the first protective layer is an epoxy resin or benzocyclobutene. 12. The method of claim 11, wherein the thickness of the first passivation layer is 100 nm to 100 占 퐉. 12. The method of claim 11, wherein the graphene / silver nanowire / graphene multilayer has a thickness of 1 nm to 100 nm. 12. The method of claim 11, wherein the second protective layer is an epoxy resin or benzocyclobutene. 12. The method of claim 11, wherein the thickness of the second protective layer is 100 nm to 100 占 퐉. 12. The method of claim 11, wherein the skin attachment film is polydimethylsiloxane. 12. The method of claim 11, wherein the skin attachment film has a thickness of 1 占 퐉 to 100 占 퐉.

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