Stretchable electronic device and manufacturing method thereof

Abstract

The present application relates to a stretchable electronic device and a manufacturing method thereof. The stretchable electronic device can overcome a trade-off between a light-emitting area and a maximum tensile ratio of a two-dimensional stretchable display, and exhibit a high tensile ratio while having excellent initial-driving performance. In addition, the stretchable electronic device can be applied to various electronic elements by excluding high-temperature and wet processes of a conventional three-dimensional stretchable display technology. The stretchable electronic device according to one embodiment of the present invention comprises: an elastic substrate; an adhesive layer disposed on the elastic substrate; an anti-adhesive layer disposed on the adhesive layer so as not to cover the edge of the adhesive layer; a plurality of islands disposed on the adhesive layer and the anti-adhesive layer so as to be spaced apart from each other; and interconnectors for connecting the plurality of islands.

Description

Stretchable electronic device and method for manufacturing the same

[0001] The present application relates to a stretchable electronic device and a method for manufacturing the same.

[0002] Recently, in the field of display-related technology, research is actively being conducted to provide stretchable displays that can freely expand and contract the screen size and freely change the shape of the screen, beyond flat, curved, foldable, and rollable displays.

[0003] One technology that has been introduced to commercialize these stretchable displays utilizes rigid islands and interconnectors. This technology's development focuses on improving the elasticity of the interconnectors that connect the two-dimensionally arranged islands. However, this structure has a fundamental limitation: it sacrifices display resolution to improve interconnector elasticity, making it difficult to simultaneously improve both elasticity and resolution.

[0004] Therefore, to overcome these limitations, a three-dimensional stretchable display that transcends the two-dimensional structure has been introduced. Mechanically guided assembly is a known technology for providing three-dimensional stretchable displays.

[0005] A method has been introduced in which an electronic element having a sacrificial layer formed on a pre-tensioned elastic substrate is transferred and bonded using one of the above techniques, the sacrificial layer is removed, and the tensioned elastic substrate is then restored to form a three-dimensional structure.

[0006] Another technique has been introduced in which an elastic substrate having a predetermined shape is stretched, electronic elements are selectively bonded to the predetermined shape of the elastic substrate, and the stretched elastic substrate is returned to form a three-dimensional structure.

[0007] However, existing studies have had technical limitations in implementing electronic devices vulnerable to high-temperature and wet processes in a three-dimensional structure, as they have required high-temperature processes of 180°C or higher to fix elastic substrates and electronic devices through covalent bonding, or wet etching processes such as sacrificial layer removal.

[0008] According to one embodiment of the present application, a stretchable electronic device capable of arranging a three-dimensional structure is provided.

[0009] According to another embodiment of the present application, a method is provided for providing a stretchable electronic device capable of arranging a three-dimensional structure without high temperature and wet processes.

[0010] According to one embodiment of the invention, a stretchable electronic device is provided, comprising: an elastic substrate; an adhesive layer disposed on the elastic substrate; an anti-adhesive layer disposed on the adhesive layer so as not to cover an edge of the adhesive layer; a plurality of islands disposed spaced apart from each other on the adhesive layer and the anti-adhesive layer; and interconnectors connecting the plurality of islands.

[0011] The above plurality of islands may be arranged in a two-dimensional structure on the same plane, or in a three-dimensional structure arranged on different planes or on the same spherical surface.

[0012] The above interconnector may be flexible so that the distance between islands connected by the interconnector can be lengthened or shortened on the same plane, and may be bendable so that islands connected by the interconnector can be positioned on different planes.

[0013] The above-mentioned anti-adhesive layer may exhibit weaker adhesion to the island than the above-mentioned adhesive layer.

[0014] The islands disposed on the anti-adhesive layer may be spaced apart from the anti-adhesive layer or may be in contact with the anti-adhesive layer.

[0015] The effective adhesion work of the above anti-adhesive layer and the island disposed on the above anti-adhesive layer is 0.01 to 0.30 J / m 2 It could be.

[0016] The ratio of the area of ​​the effective area, which is the area occupied by the island to the unit area of ​​the repeating unit of the above island and the interconnector connected thereto, may be 70% or more.

[0017] When the above multiple islands are arranged in a checkerboard pattern, the maximum tensile strength based on both axes can be 20% or more.

[0018] The above anti-adhesive layer may have an engraved pattern formed on the surface that comes into contact with the island.

[0019] The ratio of the area occupied by the negative pattern to the total area of ​​the anti-adhesive layer may be 10% to 97%.

[0020] The above anti-adhesive layer may have a thickness of 0.1 μm to 10 μm.

[0021] The island disposed on the above anti-adhesive layer may include an island substrate and an electronic element formed on at least one surface of the island substrate.

[0022] The electronic device may be a stretchable organic light emitting diode, an optoelectronic device, a transistor, a solar cell, or a battery.

[0023] The islands arranged on the adhesive layer may be the same as or different from the islands arranged on the anti-adhesive layer.

[0024] An organic light-emitting diode may be applied to an island disposed on the above-described anti-adhesive layer, and a driving element for driving the organic light-emitting diode may be applied to an island disposed on the above-described adhesive layer.

[0025] Meanwhile, according to another embodiment of the invention, a method for manufacturing a stretchable electronic device is provided, comprising: a step of applying a tensile force to an elastic substrate to stretch it; a step of disposing an adhesive layer on the stretched elastic substrate; a step of disposing an anti-adhesive layer so as not to cover an edge of the adhesive layer; a step of disposing a plurality of islands connected by interconnectors on the adhesive layer and the anti-adhesive layer; and a step of removing the tensile force applied to the elastic substrate.

[0026] The step of applying a tensile force to the elastic substrate to tension the elastic substrate may include tensioning the elastic substrate in both axial directions on the same plane as the elastic substrate.

[0027] The step of disposing the anti-adhesive layer may include applying a composition for forming an anti-adhesive layer to a template on which a relief pattern corresponding to the desired negative pattern is formed, performing at least one of a drying, polymerization, or curing process to form an anti-adhesive layer, and then transferring the same to the adhesive layer.

[0028] The step of arranging a plurality of islands connected by the above interconnectors may include forming a plurality of islands, forming interconnectors connecting the islands, and then arranging them on an adhesive layer and an anti-adhesive layer.

[0029] The step of removing the tensile force applied to the elastic substrate may include applying a compressive force to a plurality of islands arranged on the anti-adhesive layer and interconnectors connecting the islands to induce a three-dimensional structural arrangement of the plurality of islands.

[0030] A stretchable electronic device according to one embodiment of the invention overcomes the trade-off between the light-emitting area and maximum tensile strength of a two-dimensional stretchable display, and exhibits high initial operating performance (e.g., resolution, etc.) while exhibiting a high tensile strength. Furthermore, the stretchable electronic device has the advantage of being applicable to various electronic devices by excluding the high-temperature and wet processes of conventional three-dimensional stretchable display technology.

[0031] FIG. 1 is a perspective view sequentially illustrating an elastic substrate (10) tensioned in two axes, an adhesive layer (20) to be laminated thereon, an anti-adhesive layer (30), and a plurality of islands (41) arranged on a two-dimensional plane, as an example of an implementation.

[0032] FIG. 2 is a perspective view of a stretchable electronic device manufactured by sequentially stacking an adhesive layer (20), an anti-adhesive layer (30), and a plurality of islands (41) arranged on a two-dimensional plane on an elastic substrate (10) tensioned in both axes of FIG. 1, and then removing the tensile force applied to the elastic substrate (10).

[0033] Figure 3 is a cross-sectional view schematically illustrating a state in which an island (41a) is separated from an anti-adhesive layer (30) according to one implementation example.

[0034] Figure 4 is a cross-sectional view schematically illustrating a state in which an island (41a) is in contact with an anti-adhesive layer (30) according to one implementation example.

[0035] Figure 5 is an enlarged view of the portion indicated by the dotted circle (P) in Figure 2.

[0036] FIG. 6 is a perspective view of a flexible electronic device in which a plurality of islands (41a) are arranged in a three-dimensional structure according to an embodiment.

[0037] FIG. 7 is a perspective view of a flexible electronic device in which a plurality of islands (41a) are arranged on a two-dimensional plane according to an embodiment.

[0038] Figure 8 is a graph showing the adhesive strength with islands according to the area ratio of the negative pattern of the anti-adhesive layer manufactured in Examples 1 to 3.

[0039] FIG. 9 is a photograph and a scanning electron microscope image of the stretchable electronic devices manufactured in Examples 1 to 3, taken with a camera equipped with a micro lens.

[0040] Figure 10 is a photograph for evaluating the elasticity and driving performance according to two-dimensional deformation of the elastic electronic device manufactured in Example 3.

[0041] Figure 11 is a drawing for explaining r / R, which is an index of three-dimensional deformation of Figures 12 and 13.

[0042] Figure 12 is a graph showing the maximum strain according to three-dimensional deformation of the stretchable electronic device manufactured in Example 3.

[0043] Figure 13 is a photograph for evaluating the elasticity and driving performance according to three-dimensional deformation of the elastic electronic device manufactured in Example 3.

[0044] Figure 14 is a graph showing the results of evaluating the current density and brightness according to voltage while applying two-dimensional deformation to the flexible electronic device manufactured in Example 3.

[0045] Figure 15 is a graph showing the results of evaluating current efficiency according to brightness while applying two-dimensional deformation to a flexible electronic device manufactured in Example 3.

[0046] Figure 16 is a graph showing the results of evaluating EL performance according to the number of repetitions of applying and removing a tensile force at a speed of 10 mm / s to a flexible electronic device manufactured in Example 3.

[0047] Hereinafter, embodiments will be described with reference to the attached drawings. These embodiments are provided to more fully explain the present invention to those skilled in the art. The described embodiments may be modified in various ways, and the scope of the present invention is not limited to the embodiments described below. The shapes and sizes of elements in the drawings may be exaggerated for clarity.

[0048] A stretchable electronic device according to one embodiment of the invention can freely bend or stretch depending on an external force applied. The stretchable electronic device can be provided as various types of stretchable electronic devices by applying various electronic components to the island. As non-limiting examples, the stretchable electronic device can be provided as a stretchable organic light emitting diode, an optoelectronic device, a stretchable transistor, a stretchable solar cell, or a stretchable battery. Such stretchable electronic devices can be used as, for example, stretchable displays, curved or stretchable lighting, wearable or body-attachable electronic products, robotics, healthcare electronic products, etc.

[0049] Referring to FIG. 1, a stretchable electronic device of one embodiment can be manufactured by, for example, stretching an elastic substrate (10), placing an adhesive layer (20) on the stretched elastic substrate (10), placing an anti-adhesive layer (30) so as not to cover the edge of the adhesive layer (20), placing a plurality of islands (41) connected by interconnectors (43) on the adhesive layer (20) and the anti-adhesive layer (30), and then removing the tensile force applied to the elastic substrate (10).

[0050] Referring to FIG. 2, a stretchable electronic device of one embodiment may include an elastic substrate (10); an adhesive layer (20) disposed on the elastic substrate (10); an anti-adhesive layer (30) disposed on the adhesive layer (20) so as not to cover an edge of the adhesive layer (20); a plurality of islands (41) disposed spaced apart from each other on the adhesive layer (20) and the anti-adhesive layer (30); and interconnectors (43) connecting the plurality of islands (41).

[0051] The elastic substrate (10) may be a flexible substrate that can be bent and reversibly stretched and contracted. In addition, the elastic substrate (10) may be formed of an insulating material.

[0052] The elastic substrate (10) may have a high elongation. For example, the elongation of the elastic substrate (10) may be 100% or more, 300% or more, 500% or more, 600% or more, 700% or more, or 750% or more, and 1000% or less, 950% or less, or 900% or less.

[0053] The thickness of the elastic substrate (10) can be controlled depending on the type of elastic electronic device to be provided. In one example, the thickness of the elastic substrate (10) can be 1 μm or more, 50 μm or more, or 100 μm or more, and 20 mm or less, 10 mm or less, or 5 mm or less.

[0054] The elastic substrate (10) may be made of, for example, a siloxane polymer such as polydimethylsiloxane (PDMS); a urethane polymer; an olefin polymer; or a vinyl rubber such as acrylonitrile-butadiene-styrene rubber, acrylonitrile-butadiene rubber, butadiene rubber, styrene-butadiene-styrene rubber, or chloroprene rubber.

[0055] In one embodiment, a flexible electronic device uses an adhesive layer (20) to secure an island (41b) disposed on an adhesive layer (20) to an elastic substrate (10). Therefore, compared to conventional methods of securing an island to an elastic substrate through covalent bonding, there is an advantage in that a high-temperature process can be omitted.

[0056] The adhesive layer (20) can exhibit sufficient adhesive strength to firmly fix the island (41b) to the elastic substrate (10).

[0057] As an example, the effective work of adhesion between the adhesive layer (20) and the island (41b) is 1 J / m 2 It may be ideal. In addition, the upper limit of the effective work of adhesion of the adhesive layer (30) and the island (41b) is not particularly limited, but is 10 J / m 2 It may be as follows. Within this range, the island (41b) can be firmly fixed to the elastic substrate (10) and exhibit excellent durability against an applied external force, and the shape of the elastic electronic device can be deformed depending on the applied external force. The effective bonding work may be a value measured through a double cantilever beam test.

[0058] The adhesive layer (20) may have an appropriate thickness so that the laminate of the elastic substrate (10), the adhesive layer (20), and the anti-adhesion layer (30) exhibits excellent elasticity. In one example, the thickness of the adhesive layer (20) may be 0.1 ㎛ or more, 0.5 ㎛ or more, or 1 ㎛ or more, and 10 ㎛ or less, 5 ㎛ or less, or 3.5 ㎛ or less.

[0059] The adhesive layer (20) can be manufactured using any adhesive known in the art without any particular limitation, as long as it can firmly fix the island (41b) to the elastic substrate (10). The adhesive layer (20) can be formed of, for example, an acrylic adhesive or a silicone adhesive. In one example, the adhesive layer (20) can be manufactured using commercially available DOWSIL TM It can be formed with a silicone adhesive such as SE 9186.

[0060] The interconnector (43) can electrically connect the islands (41). The interconnector (43) can be shaped to relieve stress generated by an external force applied to the flexible electronic device.

[0061] In one example, the interconnector (43) may be flexible so that the distance between islands (41) connected to the interconnector (43) can be lengthened or shortened on the same plane. In addition, the interconnector (43) may be bendable so that the islands (41) connected to the interconnector (43) can be positioned on different planes (e.g., a plane or a spherical surface).

[0062] The shape of the interconnector (43) is not particularly limited, and can be formed into various shapes such as a straight line, a curve, a winding shape, or a zigzag shape.

[0063] The interconnector (43) can be formed using, for example, a metal material such as aluminum (Al), copper (Cu), gold (Au), or silver (Ag), or a conductive film.

[0064] The anti-adhesive layer (30) may exhibit a weaker adhesive force to the island (41) than the adhesive layer (20). Accordingly, depending on the external force applied to the stretchable electronic device of one embodiment, the island (41a) disposed on the anti-adhesive layer (30) may be separated from the anti-adhesive layer (30) or may come into contact with the anti-adhesive layer (30).

[0065] Referring to Fig. 3, an island (41a) disposed on an anti-adhesive layer (30) may be spaced apart from the anti-adhesive layer (30). The island (41a) may include an island substrate (401) and an electronic element (402) formed on at least one surface of the island substrate (401). Fig. 3 is an example of a case where an organic light-emitting diode (OLED) element is employed as the electronic element (402).

[0066] Referring to Fig. 4, the island (41a) spaced from the anti-adhesive layer (30) can come into contact with the anti-adhesive layer (30) again.

[0067] When a compressive force is applied to the flexible electronic device of one embodiment, the islands (41b) fixed by the adhesive layer (20) may become closer to each other. In addition, the islands (41a) arranged on the anti-adhesive layer (30) between the islands (41b) fixed to the adhesive layer (20) and the interconnectors (43) connecting them may receive compressive stress. As a result, the interconnectors (43) arranged on the anti-adhesive layer (30) may bend, and the plurality of islands (41a) may be arranged on different surfaces (e.g., a plane or a spherical surface).

[0068] Referring to FIGS. 5 and 6, a plurality of islands (41a) disposed on an anti-adhesive layer (30) subjected to compressive stress and interconnectors (43) connecting them may be buckled, and some of the plurality of islands (41a) disposed on the anti-adhesive layer (30) may be separated from the anti-adhesive layer (30) and float in the air.

[0069] When a tensile force is applied to the stretchable electronic device of one embodiment, the islands (41b) fixed by the adhesive layer (20) may move apart from each other. In addition, the islands (41a) arranged on the anti-adhesive layer (30) between the islands (41b) fixed to the adhesive layer (20) and the interconnectors (43) connecting them may be subjected to tensile stress. As a result, the interconnectors (43) arranged on the anti-adhesive layer (30) may be stretched by a pulling force at both ends, and the plurality of islands (41a) and the interconnectors (43) may be arranged on the same surface (e.g., a plane or a spherical surface).

[0070] If tensile force is applied to the interconnector (43) while it is bent as in Fig. 6, the interconnector (43) can be straightened as in Fig. 7. Thereafter, if tensile force is continuously applied, the interconnector (43) can be stretched to its maximum elongation.

[0071] In this specification, when a plurality of islands (41a) are located on the same plane, as in FIG. 7, it is expressed as “the plurality of islands are arranged in a two-dimensional structure,” and when a plurality of islands (41a) are located on different planes (e.g., a plane or a spherical surface) or on the same spherical surface, as in FIG. 6, it is expressed as “the plurality of islands are arranged in a three-dimensional structure.”

[0072] The above-described plurality of islands (41a) can be freely arranged into a two-dimensional structure and a three-dimensional structure by means of an adhesive prevention layer (30) that exhibits an adhesive strength sufficient to allow separation by an applied external force. Accordingly, the stretchable electronic device of one embodiment can be arranged into a three-dimensional structure without using a sacrificial layer, unlike a conventional three-dimensional stretchable display. Therefore, the stretchable electronic device of one embodiment can be manufactured without a wet etching process for removing the sacrificial layer, thereby providing a stretchable electronic device including an electronic element sensitive to a wet process.

[0073] The above-mentioned plurality of islands (41a) may be arranged in a two-dimensional structure in an initial state in which no external force is applied, or may be arranged in a three-dimensional structure.

[0074] In one example, the plurality of islands (41a) can be arranged to be located on different surfaces in an initial state where no external force is applied. In this state, when a tensile force is applied along an axis on the same plane as the islands (41a), the plurality of islands (41a) located on different surfaces can be arranged on the same plane (see FIG. 10), and when the plurality of islands (41a) are pushed up to a convex surface, the plurality of islands (41a) located on different surfaces can be arranged on the same spherical surface (see FIG. 13).

[0075] In the case of existing two-dimensional stretchable electronic devices, there was a limitation that in order to improve stretchability, the area occupied by the interconnector per unit area had to increase, which inevitably narrowed the effective area for driving the actual electronic device.

[0076] However, the flexible electronic device of the above embodiment can compactly arrange the island (41) and interconnector (43) compared to the two-dimensional structure due to the arrangement of the three-dimensional structure, thereby increasing the ratio of the effective area per unit area.

[0077] In one example, the stretchable electronic device of one embodiment may have a high ratio of effective area per unit area of ​​70% or more, 75% or more, 80% or more, or 85% or more. Here, the unit area refers to the area of ​​a repeating unit (see U in FIG. 1) of an island (41) and an interconnector (43) connected thereto, and the ratio of effective area per unit area refers to the ratio of the area occupied by the island (41) among the areas of the repeating unit (U) when the plurality of islands (41) are most compactly arranged. In one example, the plurality of islands (41) illustrated in FIG. 1 may be most compactly arranged in a structure such as FIG. 2.

[0078] The stretchable electronic device of one embodiment can exhibit excellent stretchability as the plurality of islands (41a) are freely arranged in a two-dimensional structure and a three-dimensional structure. In one example, when the plurality of islands (41) are arranged in a checkerboard shape as shown in FIG. 1, the maximum tensile strength based on both axes can be 20% or more, 30% or more, or 35% or more. Here, the two-axis standards refer to the horizontal axis along which the plurality of islands (41) of FIG. 1 are arranged and the vertical axis orthogonal thereto. That is, the maximum tensile strength based on both axes of 35% means that both the horizontal axis and the vertical axis are stretched by 35%.

[0079] The higher the effective area per unit area ratio and the maximum tensile rate based on both axes, the more advantageous it is, and their upper limits are not particularly limited. This test example shows the test results of a stretchable electronic device with an effective area per unit area ratio of 85% and a maximum tensile rate of 40% based on both axes. If a device with an effective area per unit area ratio of 85% and a maximum tensile rate of 40% based on both axes is to be implemented in a conventional two-dimensional stretchable electronic device structure, an interconnector with a tensile rate of 510% must be adopted. Since an interconnector with a tensile rate of 510% is difficult to implement in practice, it can be confirmed that the limitations of the conventional two-dimensional stretchable electronic device structure can be overcome by the stretchable electronic device of the above-described embodiment.

[0080] The anti-adhesive layer (30) is placed on the adhesive layer (20) so as not to cover the edge of the adhesive layer (20).

[0081] In order for the flexible electronic device of one embodiment to exhibit elasticity, it is necessary to exhibit appropriate adhesive strength so that the islands (41a) and interconnectors (43) arranged on the anti-adhesive layer (30) can freely contact and be separated from the anti-adhesive layer (30) in response to an external force applied.

[0082] The anti-adhesive layer (30) needs to exhibit weaker adhesive strength with respect to the island (41a) and the interconnector (43) than the adhesive layer (20). In addition, the anti-adhesive layer (30) needs to exhibit an appropriate level of adhesive strength so that the island (41a) and the interconnector (43) can have an appropriate critical buckling strain. The critical buckling strain refers to the compressibility at which buckling occurs, and tends to increase as the adhesive strength of the anti-adhesive layer (30) increases.

[0083] As an example, the effective work of adhesion of the anti-adhesion layer (30) and the island (41a) is 0.30 J / m 2 Below, 0.28 J / m 2 Below, 0.25 J / m 2 Below, 0.23 J / m 2 Below, 0.20 J / m 2 Below, 0.18 J / m 2 Below, 0.15 J / m 2 Below, 0.13 J / m 2 Below, 0.10 J / m 2 Below, 0.08 J / m 2 Less than or equal to 0.05 J / m 2 It may be below. In addition, the lower limit of the effective work of adhesion of the anti-adhesion layer (30) and the island (41a) is 0.001 J / m 2 or more than 0.015 J / m 2 This may be ideal. Within this range, the island (41a) and interconnector (43) can have an appropriate critical buckling strain, thereby providing a flexible electronic device that can freely deform even with a small force. The effective bonding work may be a value measured through a double cantilever beam test.

[0084] The anti-adhesive layer (30) can be formed of an appropriate material to exhibit an adhesive strength within the above range. The anti-adhesive layer (30) can be formed of, for example, a siloxane-based polymer such as polydimethylsiloxane (PDMS); a urethane-based polymer; an olefin-based polymer; or a vinyl-based rubber such as acrylonitrile-butadiene-styrene rubber, acrylonitrile-butadiene rubber, butadiene rubber, styrene-butadiene-styrene rubber, or chloroprene rubber. In one example, the anti-adhesive layer (30) can be formed of a siloxane-based polymer in terms of low elastic modulus and good process compatibility.

[0085] The adhesion prevention layer (30) can exhibit the adhesive strength within the above range by reducing the area in contact with the island (41a), etc. Specifically, the adhesion prevention layer (30) can exhibit the desired adhesive strength by forming a concave pattern on the surface in contact with the island (41a), etc., thereby reducing the area in contact with the island (41a), etc. The concave pattern is formed by forming a pattern of a specific shape inward on the surface of the adhesion prevention layer (30) so that the adhesion prevention layer (30) does not come into contact with the island (41a) or the interconnector (43).

[0086] FIG. 5 is a perspective view showing an anti-adhesive layer (30) having a hemispherical shape of an engraved pattern (31) (circular in terms of a plan view of the anti-adhesive layer (30)), and FIGS. 3 and 4 are cross-sectional views of an anti-adhesive layer (30) having a hemispherical shape of an engraved pattern (31). Referring to FIGS. 3 to 5, the engraved pattern (31) can control the adhesive strength of the anti-adhesive layer (30) by reducing the area in which the anti-adhesive layer (30) comes into contact with the island (41a) and the interconnector (43). The shape of the engraved pattern (31) is not particularly limited, and may be circular as in FIG. 5, or may be various shapes such as polygons such as triangles, squares, or pentagons, or stripes, based on the surface of the anti-adhesive layer (30) (i.e., based on a plan view). The negative pattern (31) may be formed so as not to penetrate the anti-adhesive layer (30), as shown in Fig. 5, or may be formed so as to penetrate the anti-adhesive layer (30). The negative patterns (31) formed on the anti-adhesive layer (30) may all be formed in the same shape, or may be formed in two or more shapes.

[0087] The ratio of the area occupied by the negative pattern (31) to the total area of ​​the anti-adhesive layer (30) (simply referred to as “area ratio of the negative pattern”) can be determined according to the inherent adhesive strength of the anti-adhesive layer (30). The area ratio of the negative pattern (31) can be, for example, 0% or more, 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, or 85% or more, and can be 97% or less or 95% or less. Even if the anti-adhesive layer (30) is formed of the same material, the adhesive strength can become weaker as the ratio of the negative pattern (31) increases.

[0088] The anti-adhesive layer (30) may have an appropriate thickness so that the laminate of the elastic substrate (10), the adhesive layer (20), and the anti-adhesive layer (30) has excellent elasticity, and an intaglio pattern (31) of an appropriate height can be formed on the anti-adhesive layer (30) as needed. In one example, the thickness of the anti-adhesive layer (30) may be 0.1 ㎛ or more, 0.5 ㎛ or more, or 1 ㎛ or more, and 10 ㎛ or less, 5 ㎛ or less, or 3.5 ㎛ or less. The thickness of the anti-adhesive layer (30) may refer to the thickness of a portion where the intaglio pattern (31) is not formed.

[0089] The plurality of islands (41) are classified into an island (41a) placed on the anti-adhesive layer (30) and an island (41b) placed on the adhesive layer (20).

[0090] Various electronic elements may be applied to the island (41a) placed on the anti-adhesive layer (30) depending on the elastic electronic device to be provided. Specifically, referring to FIGS. 3 and 4, the island (41a) may include an island substrate (401) and an electronic element (402) formed on at least one surface of the island substrate (401).

[0091] The island substrate (401) may be a rigid substrate, unlike the elastic substrate (10). The island substrate (401) may be, for example, a polyimide substrate.

[0092] The type of electronic device (402) is not particularly limited, and may be, for example, a stretchable organic light emitting diode, an optoelectronic device, a transistor, a solar cell, or a battery.

[0093] The island (41b) placed on the adhesive layer (20) may be the same as that applied to the island (41a) placed on the anti-adhesive layer (30) or may be different from that applied to the island (41a).

[0094] Referring to FIG. 1, a method for manufacturing a stretchable electronic device according to another embodiment includes a step of applying a tensile force to an elastic substrate (10) to stretch it; a step of arranging an adhesive layer (20) on the stretched elastic substrate (10); a step of arranging an anti-adhesive layer (30) so as not to cover an edge of the adhesive layer (20); a step of arranging a plurality of islands (41) connected by interconnectors (43) on the adhesive layer (20) and the anti-adhesive layer (30); and a step of removing the tensile force applied to the elastic substrate (10).

[0095] According to another embodiment of the manufacturing method, a plurality of islands (41) are arranged while applying tensile force to the elastic substrate (10) first, and then the tensile force is removed to induce a three-dimensional structure arrangement of the plurality of islands (41a).

[0096] In the step of applying tensile force to the elastic substrate (10) to stretch it, the elastic substrate (10) can be stretched using a method known in the art. In one example, as shown in Fig. 1, the elastic substrate (10) can be stretched in both axial directions on the same plane as the elastic substrate (10).

[0097] In the step of placing an adhesive layer (20) on a tensioned elastic substrate (10), an adhesive composition may be applied to the tensioned elastic substrate (10) or a B-stage adhesive film may be transferred. Since the adhesive layer (20) has been described in detail above, a detailed description thereof is omitted here.

[0098] In the step of placing the anti-adhesive layer (30), the anti-adhesive layer (30) may be placed so as not to cover the entire surface of the adhesive layer (20) so that the island (41b) can be fixed to the elastic substrate (10) through the adhesive layer (20). Specifically, the anti-adhesive layer (30) may be placed so as not to cover the edge of the adhesive layer (20). At this time, not covering the edge does not mean that all edges of the adhesive layer (20) are exposed, but that at least a portion of the edges are exposed.

[0099] The anti-adhesive layer (30) may be formed with an intaglio pattern (31) as described above. The intaglio pattern (31) may be formed using a template on which a relief pattern corresponding to the intaglio pattern (31) to be formed is formed. Specifically, an anti-adhesive layer forming composition may be applied to a template on which a relief pattern corresponding to the desired intaglio pattern (31) is formed, and at least one of a drying, polymerization, or curing process may be performed to form the anti-adhesive layer (30). The anti-adhesive layer (30) thus formed may be transferred to a predetermined area on the adhesive layer (20) to place the anti-adhesive layer (30) on the adhesive layer (20). Since the anti-adhesive layer (30) has been described in detail above, a detailed description thereof will be omitted here.

[0100] In the step of arranging a plurality of islands (41) connected by interconnectors (43), a plurality of islands (41) can be formed, interconnectors (43) connecting them can be formed, and then arranged on an adhesive layer (20) and an anti-adhesive layer (30).

[0101] Afterwards, by going through a step of removing the tensile force applied to the elastic substrate, a compressive force is applied to the plurality of islands (41a) arranged on the anti-adhesive layer (30) and the interconnectors (43) connecting them, thereby inducing a three-dimensional structure arrangement of the plurality of islands (41a).

[0102]

[0103] The following specific examples of the invention will further illustrate its functions and effects. However, these examples are presented as illustrative examples and do not limit the scope of the invention in any way.

[0104]

[0105] Example 1: Fabrication of a stretchable electronic device (OLED)

[0106] (1) Manufacturing of electronic components (OLED components)

[0107] Polyamic acid (KPI-1200, Komec) was spin-coated onto a 4-inch glass wafer and imidized at 280°C for 1 hour to form a 2.5 μm thick polyimide layer. The polyimide layer was patterned using a photolithography method. A first pV3D3 layer with a thickness of 160 nm was deposited on the patterned polyimide layer through a free radical polymerization reaction in an iCVD chamber using tert-butyl peroxide (TBPO) as an initiator and 1,3,5-trimethyl-1,3,5-trivinylcyclotrisiloxane (V3D3) as a monomer. A 60 nm thick Al2O3 layer was deposited on the first pV3D3 layer through atomic layer deposition (ALD, Lucida D100 NCD Co.) at 70°C using trimethylaluminum as a precursor and H2O as a reactant. A 160 nm thick second pV3D3 layer was formed on the Al2O3 layer using the same method as the first pV3D3 layer manufacturing method described above. The first pV3D3 / Al2O3 / second pV3D3 stacked structure functions as a bottom encapsulation layer of the OLED.

[0108] Each organic layer of the OLED was sequentially deposited using shadow mask technique. First, 5.8 X 10 -3A 100 nm thick indium zinc oxide (IZO) layer was selectively deposited as an anode on the second pV3D3 layer by RF sputtering in a vacuum chamber at a pressure of 10 torr. A 150 nm thick aluminum layer was deposited between the IZO patterns to form interconnectors for electrical connection using a vacuum thermal evaporator (HS-1100, Digital Optics & Vacuum). Using a vacuum thermal evaporator, a 140 nm thick 4,4'-cyclohexylidenebis[N,N-bis(4-methylphenyl)benzenamine] (TAPC) layer as a hole injection layer, a 10 nm thick tris(4-carbazoyl-9-ylphenyl) amine (TCTA) layer as a hole transport layer, a 30 nm thick TCTA: Ir(dmppy-ph)2tmd: 4,6-bis(3,5-di(pyridin-3-yl)phenyl)-2-methylpyrimidine (B3PYMPM) (48: 48: 4 wt. %) layer as an emission layer, and a 70 nm thick B3PYMPM layer as an electron transport layer were sequentially deposited on the IZO layer. Finally, a LiF (1 nm) / Al (150 nm) layer was deposited as a cathode. In the 5 X 5 island structure, the horizontal line of the cathode and the vertical line of the anode overlapped in the island area. The top encapsulation layer of the OLED was formed in the same manner as the lower encapsulation layer.

[0109] For OLED transfer, excimer laser equipment (KORONA TMThe glass wafer was removed using laser-lift off (LLO) technology via AP systems, and interconnectors were formed using silver (Ag) paste (P-100, CANS) to connect the cathode pad and anode pad of the OLED to a customized flexible printed circuit board (FPCB).

[0110]

[0111] (2) Manufacturing of flexible electronic devices

[0112] A 1 ㎛ thick fluorine resin layer (NovecTM 1700 Electronic Grade Coating, 3M) was spin-coated on a flat glass substrate (25 mm X 25 mm) and cured at room temperature for 10 minutes so that the area ratio of the negative pattern was 0% with respect to the total area of ​​the anti-adhesive layer. TM ) was used. Polydimethylsiloxane (PDMS) was spin-coated on the template and cured at 100°C for 30 minutes to produce an anti-adhesive layer (square shape of 25 mm X 25 mm, thickness of 2.6 μm).

[0113] Meanwhile, an elastic polymer (Dragon Skin 10, Smooth-on Inc.) was spin-coated and cured at room temperature for 6 hours to produce a 1 mm thick elastic substrate. A silicone adhesive (DOWSILTM SE 9186) was spin-coated while covering the edges of the elastic substrate with a release film (PI Film Tape 5413, 3M), and the release film was removed.

[0114] As shown in Fig. 1, a custom-made dual-axis stage equipped with two motorized linear translators (T-LSR075D, Zaber Technologies Inc.) was used to apply tensile force in both axes to elongate the elastic substrate coated with a silicone adhesive by 30 mm, and an alignment block was placed on the upper surface. Using the alignment block, the previously manufactured anti-stick layer was transferred so that the edges of the coated adhesive were exposed. Thereafter, the previously manufactured OLED elements were transferred onto the adhesive and anti-stick layer using the alignment block again. Next, as the adhesive was cured at room temperature to form an adhesive layer, the OLED elements placed on the adhesive layer were fixed to the elastic substrate by the adhesive layer.

[0115] After the OLED element was fixed to the elastic substrate, the tensile force applied to the elastic substrate was removed. Accordingly, the islands that had been arranged in a two-dimensional structure, as shown in Fig. 2, were arranged in a three-dimensional structure.

[0116]

[0117] Example 2: Fabrication of a stretchable electronic device (OLED)

[0118] A stretchable electronic device was manufactured in the same manner as in Example 1, except that the area ratio of the engraved pattern was 41% as the anti-adhesive layer. Specifically, a 1 ㎛ thick fluorine resin layer (NovecTM 1700 Electronic Grade Coating, 3M) was applied to a sapphire substrate (25 mm X 25 mm, HNPS01, LUMTEC, Taiwan) having a surface of a microlens (MLA) array with a minor axis of 1.4 ㎛ and a major axis of 1.8 ㎛. TM ) was formed to manufacture a template, and an anti-adhesive layer having an area ratio of the negative pattern of 41% with respect to the total area of ​​the anti-adhesive layer was manufactured in the same manner as Example 1, except that the template was used.

[0119]

[0120] Example 3: Fabrication of a stretchable electronic device (OLED)

[0121] A stretchable electronic device was manufactured in the same manner as in Example 1, except that the anti-adhesive layer had an area ratio of the engraved pattern of 88%. Specifically, a 100 nm thick Al2O3 layer was deposited on a sapphire substrate (25 mm X 25 mm, HNPS01, LUMTEC, Taiwan) having a surface of a microlens array (MLA) with a minor axis of 1.4 ㎛ and a major axis of 1.8 ㎛ through an ALD process, and a template forming a fluorinated self-assembled monolayer (SAM) using vaporized trichloro-(1H,1H,2H,2H-perfluorooctyl)silane (Sigma-Aldrich) in a vacuum desiccator was manufactured, and an anti-adhesive layer having an area ratio of the engraved pattern of 88% to the total area of ​​the anti-adhesive layer was manufactured in the same manner as in Example 1, except that the template was used.

[0122]

[0123] Test Example: Test Results of a Stretchable Electronic Device

[0124] (1) Evaluation of the adhesion of the anti-adhesive layer

[0125] The interfacial adhesion between the anti-adhesion layer manufactured in Examples 1 to 3 and the layer (pV3D3 layer) included in the island in contact with the anti-adhesion layer was measured using a double cantilever beam (DCB) test device (DTS Company, 390 Delaminator Adhesion Test System), and the results are shown in Fig. 8.

[0126] Referring to Fig. 8, in the case of Example 1 where the area ratio of the negative pattern is 0%, the effective work of adhesion is about 0.259 J / m 2For Example 2, where the area ratio of the engraved pattern is 41%, the effective bonding work is approximately 0.174 J / m 2 For Example 3, where the area ratio of the engraved pattern is 88%, the effective bonding work is approximately 0.033 J / m 2 It was.

[0127]

[0128] (2) Evaluation of the three-dimensional structural arrangement of Ireland

[0129] In order to confirm whether a plurality of islands were arranged in a three-dimensional structure within the stretchable electronic devices manufactured in Examples 1 to 3, an orthogonal view image was obtained using a camera device (ILCE-7M3, Sony) equipped with a micro lens (FE 90mm F2.8 Macro GOSS, Sony), and an SEM image was obtained using a scanning electron microscope (SEM), and these images are shown in Fig. 9. In Fig. 9, images measured for the stretchable electronic devices manufactured in Examples 1 to 3 are sequentially shown from left to right.

[0130] Referring to FIG. 9, in the case of Example 1 where the area ratio of the negative pattern was 0%, the plurality of islands arranged on the anti-adhesive layer and the interconnectors connecting them were not buckled to the desired level, but in the case of Example 2 where the area ratio of the negative pattern was 41% and Example 3 where the area ratio of the negative pattern was 88%, it was confirmed that the plurality of islands arranged on the anti-adhesive layer and the interconnectors connecting them were buckled and arranged in a three-dimensional structure. In particular, in the case of Example 3, it was confirmed that the islands and interconnectors on the anti-adhesive layer were perfectly arranged in a three-dimensional structure.

[0131]

[0132] (3) Evaluation of two-dimensional deformation of flexible electronic devices

[0133] Figure 10 is a photograph for evaluating the elasticity and actuation performance according to the two-dimensional deformation of the stretchable electronic device. Specifically, the stretchable electronic device manufactured in Example 3 is subjected to a tensile test (ε) along both axes. x , ε y ) was stretched biaxially from 0% to 40%, and it was confirmed that the OLED element was operated well under a constant current of 0.2 mA.

[0134] Referring to FIG. 10, it was confirmed that the stretchable electronic device manufactured in Example 3 operates uniformly and well without black dots or noticeable visual defects even when biaxially stretched so that the tensile strength of both axes was 0% to 40%.

[0135]

[0136] (4) Evaluation of three-dimensional deformation of flexible electronic devices

[0137] The stretchability and operating performance according to the three-dimensional deformation of the stretchable electronic device were evaluated. Specifically, a tensile force was applied to the stretchable electronic device manufactured in Example 3 using a convex surface with different r / R, and a graph for the maximum strain according to r / R was obtained and shown in Fig. 12, and a photograph that can confirm the operating state of the OLED element according to r / R is shown in Fig. 13. Referring to Fig. 11, in r / R, R is the radius of curvature, and r means half of the shortest distance between the two ends of the curvature.

[0138] Referring to FIGS. 12 and 13, when r / R is 0.2, the maximum strain is 4%, and even when r / R is as high as 1, the maximum strain is at the level of 25%, and it was confirmed that even when r / R is 1, it operates uniformly without black dots or noticeable visual defects.

[0139]

[0140] (5) Evaluation of electroluminescence performance according to tensile strength of flexible electronic devices

[0141] For the stretchable electronic device manufactured in Example 3, the tensile modulus (ε) of both axes x , ε y ) was stretched biaxially from 0% to 40%, and the electroluminescent (EL) performance of the OLED device was evaluated, as shown in Figs. 14 and 15. In addition, the process of applying and removing a tensile force at a speed of 10 mm / s to the stretchable electronic device manufactured in Example 3 was repeated, and the EL performance according to the number of repetitions was evaluated, as shown in Fig. 16.

[0142] The low leakage current confirmed in the current density-voltage characteristics of Fig. 14 is a result of the smooth surface with a root-mean-square (RMS) roughness of approximately 1 nm.

[0143] Referring to FIGS. 14 and 15, it was confirmed that the change in EL performance according to the change in the tensile ratio applied to the stretchable electronic device was very minimal. Specifically, when the tensile ratio of both axes was 40%, the current efficiency at 100 nits was 54 cd / A, which was almost the same as the current efficiency of 55 cd / A in the initial state when the tensile ratio of both axes was 0%.

[0144] Referring to Fig. 16, it was confirmed that the EL performance was well maintained even when a tensile force was repeatedly applied and removed to the stretchable electronic device. In particular, even when the process of applying and removing a tensile force was repeated 2000 times, the current density, luminance, and current efficiency decreased very little, at the level of 1.9%, 2.7%, and 0.8%, respectively, confirming the mechanical stability of the stretchable electronic device.

[0145]

[0146] [Explanation of symbols]

[0147] 10: Elastic substrate

[0148] 20: Adhesive layer

[0149] 30: Anti-adhesive layer

[0150] 41: Ireland

[0151] 41a: Island placed on the anti-adhesive layer (30)

[0152] 41b: Island placed on the adhesive layer (20)

[0153] 401: Irish Register

[0154] 402: Electronic components

[0155] 43: Interconnector

Claims

1. Elastic substrate; An adhesive layer disposed on the elastic substrate; An anti-adhesive layer disposed on the adhesive layer so as not to cover the edge of the adhesive layer; A plurality of islands spaced apart from each other on the adhesive layer and the anti-adhesive layer; and A flexible electronic device comprising interconnectors connecting the plurality of islands.

2. A flexible electronic device in accordance with claim 1, wherein the plurality of islands can be arranged in a two-dimensional structure on the same plane and in a three-dimensional structure on different planes or on the same spherical surface.

3. In the first paragraph, the interconnector is a flexible electronic device having flexibility so that the distance between islands connected by the interconnector can be lengthened or shortened on the same plane, and can be bent so that the islands connected by the interconnector can be positioned on different planes.

4. A flexible electronic device according to claim 1, wherein the anti-adhesive layer exhibits weaker adhesive strength to the island than the adhesive layer.

5. A flexible electronic device according to claim 1, wherein the island disposed on the anti-adhesive layer is spaced apart from the anti-adhesive layer or is in contact with the anti-adhesive layer.

6. In the first paragraph, the effective adhesion work of the anti-adhesion layer and the island disposed on the anti-adhesion layer is 0.01 to 0.30 J / m 2 In, flexible electronic devices.

7. A flexible electronic device in which the ratio of the effective area, which is the area occupied by the island to the unit area of ​​the repeating unit of the island and the interconnector connected thereto, in the first paragraph is 70% or more.

8. A flexible electronic device in accordance with claim 1, wherein the maximum tensile strength is 20% or more based on both axes when the plurality of islands are arranged in a checkerboard pattern.

9. A flexible electronic device according to claim 1, wherein the anti-adhesive layer has a negative pattern formed on a surface that contacts the island.

10. A stretchable electronic device in claim 9, wherein the ratio of the area occupied by the negative pattern to the total area of ​​the anti-adhesive layer is 10% to 97%.

11. A stretchable electronic device according to claim 1, wherein the anti-adhesive layer has a thickness of 0.1 ㎛ to 10 ㎛.

12. A stretchable electronic device according to claim 1, wherein the island disposed on the anti-adhesive layer includes an island substrate and an electronic element formed on at least one surface of the island substrate.

13. A stretchable electronic device according to claim 12, wherein the electronic device is a stretchable organic light emitting diode, an optoelectronic device, a transistor, a solar cell, or a battery.

14. A flexible electronic device according to claim 1, wherein the island disposed on the adhesive layer is the same as or different from the island disposed on the anti-adhesive layer.

15. A stretchable electronic device in which an organic light-emitting diode is applied to an island disposed on the anti-adhesive layer in the first paragraph, and a driving element for driving the organic light-emitting diode is applied to an island disposed on the adhesive layer.

16. A step of applying tensile force to an elastic substrate to stretch it; A step of placing an adhesive layer on a tensioned elastic substrate; A step of placing an anti-adhesive layer so as not to cover the edge of the adhesive layer; A step of arranging a plurality of islands connected by interconnectors on the adhesive layer and the anti-adhesive layer; and A method for manufacturing a stretchable electronic device, comprising a step of removing a tensile force applied to the elastic substrate.

17. A method for manufacturing an elastic electronic device, wherein in the step of applying a tensile force to the elastic substrate to stretch the elastic substrate, the elastic substrate is stretched in both axial directions on the same plane as the elastic substrate.

18. A method for manufacturing a flexible electronic device, wherein in the step of disposing the anti-adhesive layer, an anti-adhesive layer forming composition is applied to a template on which a convex pattern corresponding to the desired negative pattern is formed, and at least one of a drying, polymerization, or curing process is performed to form an anti-adhesive layer, and then this is transferred to the adhesive layer.

19. A method for manufacturing a flexible electronic device, wherein in the step of arranging a plurality of islands connected by the interconnectors in the 16th paragraph, a plurality of islands are formed, interconnectors connecting the islands are formed, and then the islands are arranged on an adhesive layer and an anti-adhesive layer.

20. A method for manufacturing an elastic electronic device, wherein in the step of removing the tensile force applied to the elastic substrate in the 16th paragraph, a compressive force is applied to a plurality of islands arranged on the anti-adhesive layer and interconnectors connecting them to induce a three-dimensional structural arrangement of the plurality of islands.

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