Stretchable Substrate

Abstract

The present disclosure relates to a flexible substrate. According to one embodiment of the present disclosure, the flexible substrate comprises an island on which an electronic element is disposed and a flexible matrix to which at least a portion of the island is coupled, wherein the island comprises a base having a three-dimensional shape including a first surface to a m-th surface and one or more branches protruding from the m-th surface and coupled to the flexible matrix, wherein the flexible matrix is ​​formed to surround the m-th surface and the one or more branches support the m-th surface so as not to be separated from the m-th surface and the flexible matrix. According to one embodiment of the present disclosure, even if the elastic substrate is subjected to any external force, the non-elastic island does not detach from the elastic matrix, thereby providing an effect.

Description

Technology Field

[0001] The present disclosure relates to a flexible substrate. More specifically, it relates to a flexible substrate in which an island on which an electronic element is disposed and a flexible matrix are formed so as not to be separated from each other, thereby improving mechanical stability and tensile strength. Background Technology

[0002] The content described in this section merely provides background information regarding the present disclosure and does not constitute prior art.

[0003] A wearable device is an electronic device that can be worn on a user's body. A wearable device is an electronic device attached to the body that offers excellent portability and convenience. A wearable device may include a wearable computer or an electronic skin (e-skin).

[0004] Wearable devices include stretchable electronics or stretchable substrates. Stretchable electronics are devices that possess elasticity against stress. Even when an externally applied force deforms the stretchable electronics, the electrical properties of the stretchable electronics do not degrade. A stretchable substrate is a flexible substrate. A stretchable substrate can operate even when it is bent or stretched by receiving an external force.

[0005] Electronic devices can be manufactured using silicon, and substrates can be manufactured using glass. However, there is a problem in that it is difficult to manufacture elastic materials using inorganic materials such as silicon and glass. Therefore, when electronic devices are manufactured using silicon and glass substrates are manufactured using glass, there is a problem in that it is difficult to manufacture flexible electronic devices or flexible substrates. If external force is applied to the electronic device or substrate, the electronic device or substrate may break or crack.

[0006] An example of a stretchable substrate is disclosed as prior art in Korean Registered Patent Publication No. 10-2561540. The prior art includes a stretchable matrix and a non-stretchable island. An electronic element or a substrate is disposed on at least a portion of the non-stretchable island. The non-stretchable island or the electronic element is formed to have a size much smaller than that of the stretchable matrix. The stretchable matrix is ​​formed to surround the non-stretchable island. The non-stretchable island includes a core having a circular or coin-like disk shape and branches protruding from the center of the non-stretchable island and spreading out in a radial shape. According to the prior art, the non-stretchable island includes a plurality of branches, so that the front of the non-stretchable island has a Ferris wheel shape.

[0007] Multiple branches are formed to be physically pulled together by hook-coupled with the elastic matrix. Therefore, when a force is applied toward the elastic matrix, the elastic matrix and the branches pull each other, preventing the non-elastic island from detaching from the elastic matrix. However, according to the prior art, the branches are placed only on the sides of the non-elastic island. Therefore, while the detachment of the non-elastic island can be prevented when an external force is applied toward the side of the non-elastic island, there is a problem that the rear of the non-elastic island may separate from the elastic matrix when an external force is applied toward the front or rear of the non-elastic island. Additionally, since the multiple branches are placed only on a two-dimensional plane, there is a problem that they cannot properly respond to external forces applied in directions other than those applied from the side of the non-elastic island. Prior art literature

[0008] Korean Patent Publication No. 10-2561540 (2023.08.01) The problem to be solved

[0009] According to one embodiment of the present disclosure, the objective is to provide a flexible substrate in which non-stretchable islands do not detach from the flexible matrix even when subjected to external forces applied in all directions.

[0010] According to one embodiment of the present disclosure, the purpose is to provide a flexible substrate that improves mechanical stability and can be used even when the flexible matrix is ​​twisted or crumpled.

[0011] The problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned problems will be clearly understood by a person skilled in the art from the description below. means of solving the problem

[0012] According to one embodiment of the present disclosure, a flexible substrate comprises an island on which an electronic element is disposed and a flexible matrix to which at least a portion of the island is coupled, wherein the island comprises a base having a three-dimensional shape including a first surface to a m-th surface (m is a natural number greater than or equal to 2) and one or more branches formed protruding from the m-th surface and coupled to the flexible matrix, wherein the flexible matrix is ​​formed to surround the m-th surface and the one or more branches support the m-th surface so as not to be separated from the m-th surface and the flexible matrix is ​​provided. Effects of the invention

[0013] According to one embodiment of the present disclosure, even if the elastic substrate is subjected to any external force, the non-elastic island does not detach from the elastic matrix, thereby providing an effect.

[0014] According to one embodiment of the present disclosure, the mechanical stability of a flexible substrate is improved, and the flexible substrate can be used even when the flexible matrix is ​​twisted or crumpled. Brief explanation of the drawing

[0015] FIG. 1 is a plan view of a flexible substrate according to one embodiment of the present disclosure. Figure 2 is a cross-sectional view along line A-A' of Figure 1. FIG. 3 is a cross-sectional view along line A-A' according to another embodiment of the present disclosure. FIG. 4a is a plan view of an island according to one embodiment of the present disclosure. FIG. 4b is a plan view of an island according to another embodiment of the present disclosure. FIG. 5 is a cross-sectional view along line A-A' according to another embodiment of the present disclosure. FIG. 6 is a conceptual diagram showing a flexible substrate according to one embodiment of the present disclosure. FIG. 7 is a photograph showing the process of a tensile force test of a flexible substrate according to one embodiment of the present disclosure. FIG. 8 is a photograph and conceptual diagram showing the process of a shear force test of a flexible substrate according to one embodiment of the present disclosure. FIG. 9 is a conceptual diagram showing a base according to another embodiment of the present disclosure. FIG. 10 is a photograph showing the process of a tensile force test of a flexible substrate according to another embodiment of the present disclosure. Figure 11 is a graph showing the results of tensile force tests in the horizontal and vertical directions according to the shape of the base. FIG. 12 is a conceptual diagram showing the arrangement of branches according to another embodiment of the present disclosure. Figure 13 is a graph showing the extent to which each variable affects the change in tensile force of the flexible substrate. Figure 14 is a graph showing the results of a tensile force test according to the number of branches. Figure 15 is a graph showing the results of a tensile force test according to the material of the elastic matrix. FIG. 16 is a photograph and graph showing the results of a shear force test of a flexible substrate according to one embodiment of the present disclosure. FIG. 17 is a photograph showing the process of a tensile force test of a flexible substrate according to another embodiment of the present disclosure. FIG. 18 is a photograph of an example of use in which a flexible substrate according to one embodiment of the present disclosure is applied to a display. FIG. 19 is a photograph of an example of use in which a flexible substrate according to one embodiment of the present disclosure is applied to a battery. Specific details for implementing the invention

[0016] Some embodiments of the present disclosure are described in detail below with reference to the exemplary drawings. It should be noted that in assigning reference numerals to the components of each drawing, the same components are given the same reference numeral whenever possible, even if they are shown in different drawings. Furthermore, in describing the present disclosure, if it is determined that a detailed description of related known components or functions could obscure the essence of the present disclosure, such detailed description is omitted.

[0017] In describing the components of the embodiments according to the present disclosure, symbols such as first, second, i), ii), a), b), etc., may be used. These symbols are intended only to distinguish the components from other components, and the essence, order, or sequence of the components is not limited by the symbols. When a part in the specification is described as 'comprising' or 'having' a component, this means that, unless explicitly stated otherwise, it does not exclude other components but may include additional components.

[0018] In describing the components of the present invention, terms such as first, second, A, B, (a), (b), etc., may be used. These terms are intended merely to distinguish the components from other components, and the essence, order, or sequence of the components is not limited by such terms.

[0019] Where it is stated that one component is 'connected', 'combined', or 'joined' to another component, it should be understood that while the component may be directly connected or joined to the other component, another component may also be 'connected', 'combined', or 'joined' between each component.

[0020] Unless otherwise stated, it should be noted that the description of any one embodiment may also apply to other embodiments.

[0021] The description of the invention disclosed below, together with the accompanying drawings, is intended to describe exemplary embodiments of the invention and is not intended to represent the only embodiment in which the invention may be practiced.

[0022] According to one embodiment of the present disclosure, stretchability and non-stretchability include the following meanings. Place a material with a length of on the x-axis. The left end of the material Place at the coordinates, and the right edge of the material After placing it at the coordinates, pull the right end of the material toward the (+) x-axis direction. The right end coordinates at the moment the material is torn or destroyed are In the case of, cast The value divided by can be defined as the external deformation rate.

[0023] Define the meaning of elasticity and non-stretchability using external strain values, and class Criteria for stretchable and non-stretchable materials can be defined by comparing values. Stretchable materials are materials with an external deformation rate exceeding 5%, It is a material. Non-stretchable materials are materials with an external deformation rate of 5% or less, It is a material.

[0024] FIG. 1 is a plan view of a flexible substrate according to one embodiment of the present disclosure.

[0025] Referring to FIG. 1, a flexible substrate (10) according to one embodiment of the present disclosure includes an island (100) and a flexible matrix (200). An electronic element (300) may be disposed on at least a portion of the island (100). The electronic element (300) is disposed on the upper surface or inside the island (100). The flexible substrate (10) may further include a plurality of electronic elements (300), and the plurality of electronic elements (300) may be stacked and disposed on at least a portion of the island (100). The island (100) may be formed using a non-flexible material. When the island (100) is disposed on the flexible matrix (200), at least a portion of the island (100) is bonded to one surface of the flexible matrix (200).

[0026] According to one embodiment of the present disclosure, the island (100) may include a base (110) and one or more branches (120). The base (110) has a three-dimensional shape, and the branches (120) are formed to protrude from at least a portion of the base (110) and are combined with an elastic matrix (200).

[0027] The base (110) may have a three-dimensional shape including a first surface to a m-th surface (m is a natural number greater than or equal to 2). A branch (120) is formed to protrude from the m-th surface and is coupled to an elastic matrix (200). More specifically, the branch (120) and the elastic matrix (200) may be hook-coupled to support each other. The elastic matrix (200) is formed to surround the m-th surface.

[0028] When the base (110) includes the third to the mth surface, the branch (120) is formed to protrude from all surfaces except the first surface (111), and the elastic matrix (200) may be formed to wrap around all surfaces except the first surface (111). When the elastic matrix (200) and the island (100) are combined, the elastic matrix (200) may be formed with a recess facing the exact opposite direction of the first direction so as to contact the mth surface. The electronic element (300) may be laminated on the first surface (111), and the first surface (111) may be formed to be exposed toward the first direction.

[0029] The first direction may be a direction from the interior of the flexible substrate (10) toward the upper surface of the flexible substrate (10). The first direction may be the same direction as the z-axis direction and may be a direction parallel to the z-axis direction. The direction opposite to the first direction may be the same direction as the z-axis direction and may be a direction parallel to the z-axis direction. A flexible matrix (200), an island (100), and an electronic element (300) may be stacked along the first direction. When the flexible matrix (200) and the island (100) are combined, the first surface (111) is exposed toward the first direction, and the m-th surface is formed protruding along the direction opposite to the first direction to be combined with the flexible matrix (200).

[0030] According to one embodiment of the present disclosure, the electronic element (300) may be a chip such as an LED or a semiconductor. In order to increase the portability or convenience of the wearable device, the wearable device may include a power supply element such as a battery or a solar cell, without receiving power through a power outlet or plug. When manufacturing a wearable device using a flexible substrate (10), the portability of the wearable device can be maximized by placing a battery in at least a part of the island (100).

[0031] According to one embodiment of the present disclosure, an organic solar cell (OSC) may be disposed on the upper surface of an island (100). An organic solar cell is a device that converts light into electrical energy using an organic semiconductor material. The organic semiconductor material forms a photoactive layer. The organic semiconductor material includes an organic polymer chain, and the organic polymer chain is as described in Formula 1, It has a conjugated system, including bonds. A conjugated system is a structure in which molecules forming the main chain repeat single and double bonds.

[0032]

[0033] The organic polymer chain has a conjugated structure as described in Formula 1, and when a material is formed using the organic polymer chain, it has excellent flexibility due to the conjugated structure. Therefore, when an organic solar cell is placed on the upper surface of the island (100), a wearable device that is inexpensive, lightweight, and highly flexible can be manufactured.

[0034] According to one embodiment of the present disclosure, the elastic matrix (200) may be formed using a material selected from the group comprising EcoFlex, silicone, rubber, polymer, organosilicon compound, and polydimethylsiloxane (PDMS). The elastic matrix (200) may be manufactured using any material that imparts flexibility or elasticity to the elastic matrix (200). The elastic matrix (200) is formed to have flexibility and elasticity so that it does not easily tear even when one side of the elastic matrix (200) is held and stretched or tensile force is applied. Even when the elastic matrix (200) is bent, the elastic matrix (200) is formed so that no wrinkles or fold marks remain on one side.

[0035]

[0036] As described in Chemical Formula 2, polydimethylsiloxane contains silicon and oxygen instead of carbon in the polymer main chain. Polydimethylsiloxane contains a methyl group on the silicon atoms in the main chain, constituting at least a portion of an organosilicon compound. EcoFlex contains at least a portion of polydimethylsiloxane. Polydimethylsiloxane has the advantages of being optically transparent and having low toxicity and reactivity. When a stretchable matrix (200) is formed using polydimethylsiloxane, a transparent and low-reactivity wearable device can be easily manufactured. The wearable device does not cause allergic reactions, etc., even when in contact with the skin.

[0037] Figure 2 is a cross-sectional view along line A-A' of Figure 1.

[0038] Referring to FIG. 2, the base (110) may have a hemispherical shape. When the flexible substrate (10) includes a hemispherical base (110), the first surface (111) has a radius It has a circular shape. The m-th surface is A base (110) includes a curved surface having a radius, wherein the first surface (111) and the m-th surface are combined. It is formed to have a hemispherical shape with a radius.

[0039] According to one embodiment of the present disclosure, a flexible substrate (10) receives a tensile force and tensile stress, ) occurs, and receiving shear force, shear stress ... occurs. The flexible substrate (10) is formed such that it does not break even when subjected to greater tensile stress or greater shear stress, including an island (100). Tensile force refers to a force that pulls both ends of an object, and shear force refers to a force acting parallel to the cross-section of an object.

[0040] Referring to FIG. 2(a), when tensile force is applied by pulling both sides of the elastic matrix (200) in the (+) x-axis direction and the (-) x-axis direction, respectively, tensile stress This occurs. Referring to FIG. 2(b), when tensile force is applied by pulling the front and rear surfaces of the elastic matrix (200) in the (+) z-axis direction and the (-) z-axis direction, respectively, the tensile stress ... occurs. Referring to FIG. 2(c), when a shear force in the +x-axis direction is applied to the electronic element (300), shear stress It occurs.

[0041] The elastic matrix (200) is greater than a certain value Upon receiving, if the external strain is exceeded, the elastic matrix (200) may be torn parallel to the z-axis direction, or the side of the island (100) and the elastic matrix (200) may be separated. When the elastic matrix (200) exceeds a certain value Upon receiving, if the external strain is exceeded, the elastic matrix (200) may be torn parallel to the x-axis direction, or the lower surface of the island (100) and the elastic matrix (200) may be separated. When the elastic matrix (200) exceeds a certain value When receiving, the island (100) may be pushed out of the elastic matrix (200) or the island (100) may detach from the elastic matrix (200).

[0042] FIG. 3 is a cross-sectional view along line A-A' according to another embodiment of the present disclosure.

[0043] Referring to FIG. 3, the base (110) may have a hemispheroid shape. When the flexible substrate (10) includes a base (110) having a hemispheroid shape, the first surface (111) has a radius It has a circular shape, but faces the exact opposite direction of the first direction, It has a depth. When looking at the side of the flexible substrate (10) in the +y-axis direction, the base (110) has a width and the height It can have a semi-elliptical shape. and The respective lengths of, and Depending on the ratio of lengths, the adhesion between the island (100) and the elastic matrix (200) may vary. A flexible substrate (10) with optimal conditions can be manufactured by adjusting the value.

[0044] Referring to Fig. 3(a), And, referring to Fig. 3(b), It is. Ireland (100)'s The larger the value, the larger the flexible substrate (10) It is not destroyed by, but smaller It can be destroyed by. Ireland (100)'s The smaller the value, the larger the flexible substrate (10) It is not destroyed by, but smaller It can be destroyed by.

[0045] According to one embodiment of the present disclosure, the base (110) may have a hemi-ellipsoidal shape. The ellipsoid may include both a semi-rotational ellipsoid and a tri-axial ellipsoid. A tri-axial ellipsoid is an ellipsoid in which the radii of the x-axis, y-axis, and z-axis are all different. When the flexible substrate (10) includes a base (110) having a hemi-ellipsoidal shape, the first surface (111) has a length of the first axis and the length of the second axis It has an elliptical shape. The base (110) faces the exact opposite direction of the first direction, It has the depth of , and By adjusting the value of, an optimal flexible substrate (10) according to the use of the wearable device can be manufactured.

[0046] The island (100) may include a base (110) having a different three-dimensional shape other than a hemisphere or a semi-ellipse. The base (110) may have a regular hexahedron, a cuboid, and a cone shape. Depending on the use of the flexible substrate (10) and the arrangement of the circuit, the flexible substrate (10) can be manufactured using a base (110) having various shapes.

[0047] According to one embodiment of the present disclosure, the flexible substrate (10) may further include a plurality of islands (100). One or more electronic elements (300) may be disposed on each of the plurality of islands (100). Different types of electronic elements (300) may be disposed on each of the islands (100), and the islands (100) and electronic elements (300) may be efficiently disposed according to the circuit configuration of the wearable device. When the flexible substrate (10) further includes a plurality of islands (100), each island (100) may include a base (110) of a different shape.

[0048] FIG. 4a is a plan view of an island according to one embodiment of the present disclosure.

[0049] Referring to FIG. 4a, the island (100) may include one or more branches (120) that protrude from the second to m-th surfaces and are combined with the elastic matrix (200). If the first surface (111) has a circular shape, each branch (120) may be arranged to have a radial shape from the center of the first surface (111).

[0050] One or more branches (120) may further include the first to nth branches (not shown). n may be a natural number greater than or equal to 24. The first to nth branches may be formed protruding from the second to mth surfaces and may be arranged adjacent to the first surface (111). More specifically, when the first surface (111) has a circular shape, the first to nth branches are arranged to have an equal angle from the center of the first surface (111). 24 imaginary radial lines are drawn from the center of the first surface (111), and the first to 24th branches are arranged at the parts where each radial line meets the perimeter of the first surface (111). The first branch and the second branch, and the 24th branch and the first branch each form an angle of 15 degrees.

[0051] According to one embodiment of the present disclosure, the branch (120) is formed to have a 'T' shape. The 'T'-shaped branch (120) and the elastic matrix (200) can be hook-coupled. The branch (120) and the elastic matrix (200) are formed to physically pull each other so that the island (100) does not detach from the elastic matrix (200). When one side of the branch (120) includes a 'T' shape, the diameter of the top of the branch (120) has a longer diameter than the diameter of the bottom. When the branch (120) and the base (110) are coupled, the bottom of the branch (120) is coupled to the base (110). The top of the branch (120) is located further from the center of the base (110), and the bottom of the branch is located closer to the center of the base (110).

[0052] The branch (120) may include a head (121) and a body (122). The head (121) is formed to be coupled with at least a portion of the elastic matrix (200) to secure the island (100) to the elastic matrix (200). The head (121) is formed so that the branch (120) and the elastic matrix (200) are hook-coupled. One end of the body (122) is coupled with at least a portion of the head (121), and the other end of the body (122) is coupled with at least a portion of the m-th surface.

[0053] According to one embodiment of the present disclosure, the head (121) has a diameter and the height It can have a cylindrical shape. The body (122) has a diameter and the height It can have a cylindrical shape. Is Formed to have a larger value, the branch (120) has a 'T' shape. When the first surface (111) has a circular shape and is viewed in the xy plane from the top of the flexible substrate (10), the radius of the first surface (111) is Having the value of, the radius of the island (100) is It has the value of. By adjusting the value of , a flexible substrate (10) or wearable device having optimal conditions can be manufactured.

[0054] FIG. 4b is a plan view of an island according to another embodiment of the present disclosure.

[0055] Referring to FIG. 4b, the branch (120) may include a body (122) having a trapezoidal shape on its side. More specifically, the body (122) may be formed to have a truncated cone shape. The top of the body (122) The lower part of the body (122) has a diameter of It has a diameter. The upper part of the body (122) is joined to at least a part of the head (121), and the lower part is joined to at least a part of the m-th surface. Is With a larger value, the head (121) and base (110) can be stably combined to support the branch (120). As long as the island (100) and the elastic matrix (200) can be effectively hook-coupled, the body (122) may have any shape.

[0056] FIG. 5 is a cross-sectional view along line A-A' according to another embodiment of the present disclosure.

[0057] Referring to FIG. 5(a), the island (100) may further include a fixed portion. When the island (100) further includes a fixed portion, the electronic element (300) is received in the fixed portion. The fixed portion is formed by a recess extending from the first surface (111) toward the interior of the base (110), and the electronic element (300) can be fitted into the fixed portion.

[0058] Referring to FIG. 5(b), the island (100) can be placed inside the flexible matrix (200). The flexible matrix (200) is formed to surround the electronic element (300) and the island (100). If the flexible matrix (200) is manufactured using a material with high light transmittance, a transparent flexible substrate (10) can be manufactured. Even if the island (100) and the LED element are placed inside the flexible matrix (200), light emitted from the LED can pass through the flexible matrix (200). If the island (100) is placed inside the flexible matrix (200), a flexible substrate (10) can be manufactured that has increased durability and prevents the island (100) from easily detaching.

[0059] FIG. 6 is a conceptual diagram showing a flexible substrate according to one embodiment of the present disclosure.

[0060] Referring to FIG. 6, the island (100) was made using Vero Ultra, a material from Stratasys (USA). The island (100) was manufactured by molding the Vero Ultra material using Stratasys’ J55 Prime 3D printer. The J55 Prime printer has a polyjet printing type. When manufacturing the island (100) having a hemispherical base (110), the diameter and height of the island (100) were manufactured to be 12 mm and 6 mm, respectively. The diameter of the island (100) was maintained at 12 mm, but the height of the island (100) was adjusted to have a semi-elliptical base (110).

[0061] The elastic matrix (200) was prepared using EcoFlex Gel, EcoFlex 10, EcoFlex 30, EcoFlex 50, and Dragon Skin 10 NV (hereinafter Smooth-On, USA). When preparing the elastic matrix (200) using EcoFlex 10, Part A and Part B of EcoFlex 10 were mixed in an oil mixer (Thinky AR-100, Japan) and mixed for 2 minutes and deforming for 30 seconds. When preparing the elastic matrix (200) using EcoFlex 30 and EcoFlex 50, Part A and Part B were mixed under the same conditions.

[0062] The island (100) was placed in a mold having a volume of 55 mm × 55 mm × 8 mm, and an unhardened liquid material was poured in and cured at room temperature for 4 hours. A material forming an elastic matrix (200) was injected into the mold, and the height of the material was injected such that it was equal to the height of the island (100). The material was cured to prepare a sample.

[0063] FIG. 7 is a photograph showing the process of a tensile force test of a flexible substrate according to one embodiment of the present disclosure.

[0064] Referring to FIG. 7, the top and bottom of the elastic substrate (10) were fixed to a jig. A tensile force test was performed by applying a vertical force to the top of the elastic substrate (10) and pulling it. A tensile force test was performed by applying a vertical force to the top of the elastic substrate (10) and pulling it, and measuring the force at the moment when the elastic matrix (200) was torn or the elastic substrate (10) was destroyed.

[0065] FIG. 8 is a photograph and conceptual diagram showing the process of a shear force test of a flexible substrate according to one embodiment of the present disclosure.

[0066] Referring to FIG. 8, the 3D FWI (3D Ferris Wheel Island) can be defined as a Ferris wheel-shaped island (100). The 3D FWI is an island according to the prior art and can serve as a comparison group in the experimental process. The upper end of the elastic matrix (200) was fixed to a jig, and the upper end of the elastic matrix (200) was pulled upward. A rigid member was attached to at least a part of the island (100), and the island (100) was pulled downward. The elastic matrix (200) and the island (100) were pulled simultaneously, and the force at the moment the island (100) detached from the elastic matrix (200) was measured to perform a shear force test.

[0067] FIG. 9 is a conceptual diagram showing a base according to another embodiment of the present disclosure. FIG. 10 is a photograph showing the process of a tensile force test of a flexible substrate according to another embodiment of the present disclosure.

[0068] Referring to FIGS. 9 and 10, the island (100) is manufactured to have a base (110) in the shape of a cube, a rectangular prism, and a cone, in addition to a base (110) in the shape of a hemisphere or a semi-ellipse. When the island (100) includes a base (110) in the shape of a cube, a rectangular prism, and a cone, the tensile or shear force is improved compared to the prior art. However, compared to the island (100) including a hemisphere or semi-ellipse base (110), stress distribution is not efficient, so the branch (120) is easily broken or the base (110) is easily destroyed.

[0069] Figure 11 is a graph showing the results of tensile force tests in the horizontal and vertical directions according to the shape of the base.

[0070] Referring to FIG. 11, the flexible substrate (10) includes a base (110) in the shape of a hemisphere or a semi-ellipse. A represents the height of the base (110), and B represents the radius of the base (110). Thus, A and correspond to each other, and B and These correspond to each other.

[0071] When a force is applied to the flexible substrate (10) in the (+) x-axis direction and the (-) x-axis direction, a horizontal force and This occurs, and the horizontal tensile force can be measured. When a force is applied to the elastic substrate (10) in the (+) z-axis direction and the (-) z-axis direction, the vertical force and This occurs, and the tensile force in the vertical direction can be measured.

[0072] The strain at failure is the initial length of the flexible substrate (10). and the length at the point where destruction begins initial length It is defined as the ratio of the length excluding . Elongation can be expressed by Equation 1.

[0073]

[0074] For example, of a flexible substrate (10). is 100 mm and If the value is 240 mm, the elongation is It becomes. The elongation rate is the elongation rate at the point when the elastic substrate (10) breaks.

[0075] When the base (110) has a hemispherical shape, This is the case. When the flexible substrate (10) is stretched in the (+) z-axis direction and the (-) z-axis direction and stretches about 3.5 times its initial height (when the elongation rate is about 250%), it can be seen that the flexible substrate (10) is destroyed (see the vertical part of the graph). When the flexible substrate (10) is stretched in the (+) x-axis direction and the (-) x-axis direction and stretches about 4.3 times its initial width (when the elongation rate is about 330%), it can be seen that the flexible substrate (10) is destroyed (see the horizontal part of the graph).

[0076] When the base (110) has a short semi-elliptical shape facing the vertical direction ( In the case of), the flexible substrate (10) is larger While not destroyed by, smaller It is destroyed by. In the case where the base (110) has a long semi-elliptical shape facing the vertical direction ( In the case of), the flexible substrate (10) is larger While not destroyed by, smaller It is destroyed by. It can be seen that when the value is between 0.6 and 1.4, an island (100) with optimal durability can be manufactured.

[0077] FIG. 12 is a conceptual diagram showing the arrangement of branches according to another embodiment of the present disclosure. FIG. 13 is a graph showing the extent to which each variable affects the change in tensile force of a flexible substrate.

[0078] Referring to FIGS. 12 and 13, the branch (120) may include heads (121) and bodies (122) of various sizes, and may combine a variety of branches (120) and bases (110). Sixteen different islands (100) were manufactured and classified according to four variables. The variables are, respectively: ① the number of branches (120), ② the diameter of the island (100) and the diameter of the base (110), ③ the length of the head (121) and the length of the body (122), and ④ the distance between each head (121) and the diameter of the head (121).

[0079] ① is defined as n (the number of teeth) and is the number of branches from the first to the nth. ② is defined as the r / R ratio, and It corresponds to the value. Referring to Fig. 13, r is the radius of the base, and R is the radius of the island or the sum of the heights of the base and the basin. ③ is defined as the a / b ratio, and Corresponds to the value. Referring to Fig. 13, a is the height of the head and b is the height of the body. ④ is defined as the p / I ratio, and It corresponds to the value. Referring to FIG. 13, p is the distance between each head, and I is the diameter of the head. Referring to the graph, it can be seen that the tensile force of the flexible substrate (10) is affected in the order of ①, ②, ③, ④.

[0080] Figure 14 is a graph showing the results of a tensile force test according to the number of branches.

[0081] Referring to FIG. 14, it can be seen that when performing a tensile strength measurement experiment by fixing variables ② through ④ and adjusting variable ③, the elongation rate is improved. The horizontal axis of the graph represents the number of branches (120), and the vertical axis of the graph represents the elongation rate. The I-shape extending vertically from the point on the graph represents the standard deviation of the elongation rate. The branches (120) are arranged with 0 (when the branches (120) are not arranged and the island (100) itself is in a hemispherical shape, and the experiment is conducted on a control group), 6 to 24, centered on the first surface (111). The branches (120) are arranged to have a number that is a multiple of 6, and are arranged to have a radial shape based on the center of the first surface (111). It can be seen that when there are 18 or more branches (120), the elongation rate is improved, and when there are 24 branches (120), the standard deviation is reduced, and the reliability of the experimental results is also improved.

[0082] Figure 15 is a graph showing the results of a tensile force test according to the material of the elastic matrix.

[0083] Referring to FIG. 15, the tensile strength of the elastic matrix (200) was measured by comparing the case where the island (100) does not include a branch (120) with the case where the island (100) includes a branch (120). The horizontal axis of the graph represents the material of the elastic matrix (200), and the vertical axis of the graph represents the elongation rate. The I-shape extending vertically from the center of the graph represents the standard deviation of the elongation rate.

[0084] EcoFlex contains at least a portion of polydimethylsiloxane and a curing agent. EcoFlex 10 is the material with the lowest hardness, and EcoFlex 50 is the material with the highest hardness. EcoFlex 10 to 50 are solid materials, and EcoFlex Gel is a gel-type material. When a flexible substrate (10) is manufactured using EcoFlex Gel or EcoFlex 10, it can be seen that the elongation rate is improved. It can be seen that when the island (100) does not contain branches (120) and the hardness of the flexible matrix (200) is high, the elongation rate decreases rapidly. It can be seen that when the island (100) contains branches (120), the elongation rate is maintained at approximately 150% even if the hardness of the flexible matrix is ​​high.

[0085] FIG. 16 is a photograph and graph showing the results of a shear force test of a flexible substrate according to one embodiment of the present disclosure.

[0086] Referring to FIG. 16, the relationship between the inclusion of the branch (120) and the magnitude of the shear force can be seen. The case where the island (100) does not include the branch (120) and the case where it includes the branch (120) were compared, and the shear force of the flexible substrate (10) was measured. The graph on the right shows the relationship between the magnitude of the shear force applied to the electronic device (300) and the strain ratio. The horizontal axis of the graph represents the strain ratio of the flexible substrate (10), and the vertical axis of the graph represents the shear force applied to the flexible substrate (10). The photograph on the left is a picture of the shape of the flexible substrate (10) corresponding to each point on the graph. Points (1) to (6) on the graph correspond to points (1) to (6) in the photograph, respectively. The strain ratio is the initial length of the flexible substrate (10). and the length at the point in time when shear force is applied to the flexible substrate (10) initial length It is defined as the ratio of the length excluding . The elongation rate can be expressed by mathematical formula 2.

[0087]

[0088] For example, of a flexible substrate (10). is 100 mm and If the value is 240 mm, the elongation rate It becomes. The elongation rate is the elongation rate at the point when the elastic substrate (10) breaks.

[0089] The electronic element (300) is fixed, and a shear force is applied by pulling the side of the elastic matrix (200). When the elastic matrix (200) is stretched, shear stress is generated between the elastic matrix (200) and the island (100). When the elastic matrix (200) is stretched, the elongation rate and shear stress increase proportionally (sections (1) to (2) of the graph). However, when the elastic matrix (200) is stretched beyond a certain length, the shear stress no longer increases proportionally to the elongation rate. The elastic matrix (200) and the island (100) begin to separate (point (2) of the graph). When the elastic matrix (200) and the island separate, a gap may occur. When the elastic matrix (200) is pulled further to increase the elongation rate, the size of the gap increases, and the shear stress no longer increases (point (3) of the graph).

[0090] Even after the elastic matrix (200) and the island (100) begin to separate, shear stress of a certain magnitude or greater remains inside the elastic matrix (200) (sections (4) to (5) of the graph). However, if the elastic matrix (200) is pulled further to increase the elongation rate, the elastic matrix (200) is completely destroyed or the elastic matrix (200) and the island (100) are completely separated. When the elastic matrix (200) and the island (100) are completely separated, the shear stress decreases rapidly (point (6) of the graph).

[0091] When the island (100) does not include a branch (120), the elongation rate of the flexible substrate (10) against the shear force is only about 50%, but when the island (100) includes a branch (120), it can be seen that it is about 200%. Referring to the graph, at (2), a crack began to form between the island (100) and the flexible matrix (200), and at (4), the island (100) and the flexible matrix (200) began to separate. At (6), the island (100) and the flexible matrix (200) were completely separated.

[0092] FIG. 17 is a photograph showing the process of a tensile force test of a flexible substrate according to another embodiment of the present disclosure.

[0093] Referring to FIG. 17, the process of a tensile strength test is shown when the flexible substrate (10) includes a plurality of islands (100). It can be confirmed that no cracks occur even when the flexible substrate (10) includes a plurality of islands (100). According to one embodiment of the present disclosure, a flexible substrate (10) with improved tensile strength can be manufactured even when including a plurality of islands (100) and electronic elements (300).

[0094] FIG. 18 is a photograph of an example of use in which a flexible substrate according to one embodiment of the present disclosure is applied to a display. FIG. 19 is a photograph of an example of use in which a flexible substrate according to one embodiment of the present disclosure is applied to a battery.

[0095] Referring to FIG. 18, an LED chip was placed on the island (100). When the LED chip was placed on the flexible substrate (10), it was confirmed that it operates even under various deformations. Referring to FIG. 19, a battery was placed on the island (100). When the battery was placed on the flexible substrate (10), the LED was observed to light up, confirming that the battery operates. The results of this experiment demonstrate the high versatility of the flexible substrate (10). The results of this experiment suggest that the flexible substrate (10) can be used in various fields such as next-generation preforms, displays, batteries, and the robot industry.

[0096] According to one embodiment of the present disclosure, the problems associated with the island (100) having a circular or Ferris wheel shape according to the prior art can be solved. When the island (100) according to the prior art is combined with a polymer substrate, the durability is weak and the mechanical stability is low, whereas the elastic substrate (10) improves the maximum tensile strength. When an external force is applied to the elastic substrate (10) to crumple or stretch the elastic substrate (10), the island (100) does not easily detach from the elastic matrix (200). In addition, when the elastic substrate (10) is attached to the skin, the island (100) does not easily detach from the elastic matrix (200). Therefore, a wearable device can be easily manufactured using the elastic substrate (10), or a sensor, battery, and display included inside the wearable device can be easily manufactured.

[0097] The above description is merely an illustrative explanation of the technical concept of the present embodiment, and a person skilled in the art to which the present embodiment belongs would be able to make various modifications and variations within the scope of the essential characteristics of the present embodiment. Accordingly, the present embodiments are intended to explain, not limit, the technical concept of the present embodiment, and the scope of the technical concept of the present embodiment is not limited by these embodiments. The scope of protection of the present embodiment shall be interpreted by the claims below, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of rights of the present embodiment. Explanation of the symbols

[0098] 10: Flexible substrate 100: Ireland 110: Bass 111: Page 1 120: Basin 121: Head 122: Body 200: Stretch Matrix 300: Electronic components

Claims

Claim 1 A flexible substrate comprises: an island on which an electronic element is disposed; and a flexible matrix to which at least a portion of the island is coupled, wherein the island comprises a base having a three-dimensional shape including a first surface to an m-th surface (m is a natural number greater than or equal to 2); and one or more branches formed protruding from the m-th surface and coupled to the flexible matrix, wherein the first surface has a radius It is a plane having a circular shape, and the m-th plane has a radius A flexible substrate having a curved surface, wherein the flexible matrix is ​​formed to surround the m-th surface, and the one or more branches support the m-th surface so as not to separate the m-th surface and the flexible matrix. Claim 2 A flexible substrate according to claim 1, wherein the electronic element is laminated on the first surface, and the first surface is formed to be exposed toward a first direction, and the flexible matrix is ​​formed with a groove facing the exact opposite direction of the first direction so as to contact the m-th surface. Claim 3 delete Claim 4 In claim 1, the m-th surface is the base A flexible substrate formed to have a hemispherical shape having a radius. Claim 5 In claim 1, the m-th surface is such that the base faces the exact opposite direction of the first direction. A flexible substrate formed to have a hemispheroid shape having a depth. Claim 6 In paragraph 5, the above base is, A flexible substrate formed to have a value of 0.6 to 1.

4. Claim 7 In claim 1, the one or more branches are arranged to have a radial shape from the center of the first surface, forming a flexible substrate. Claim 8 In claim 7, the one or more branches include a first branch to an nth branch (n is a natural number greater than or equal to 24), and the first to nth branches are formed protruding from the mth surface, formed adjacent to the first surface, and arranged to have a radial shape from the center of the first surface, forming a flexible substrate. Claim 9 A flexible substrate according to claim 1, wherein one side of the branch is formed to have a 'T' shape, the upper end is coupled to at least a part of the flexible matrix, and the lower end is coupled to at least a part of the m-th side. Claim 10 In claim 9, the branch comprises: a head that secures the island to the elastic matrix by being coupled to at least a portion of the elastic matrix; and a body having one end coupled to at least a portion of the head and the other end coupled to at least a portion of the m-th surface, the elastic substrate. Claim 11 In claim 10, the head is a flexible substrate formed such that the branch and the flexible matrix are hook-coupled. Claim 12 In item 10, the above head has a diameter and the height The body has a cylindrical shape, and the diameter is and the height It has a cylindrical shape, but the above The above A flexible substrate with a larger value. Claim 13 In paragraph 12, the above body has an upper portion coupled to at least a part of the head, a lower portion coupled to at least a part of the m-th surface, and the diameter of the upper portion and the diameter of the bottom is and the height It has the shape of a truncated cone, but the above The above A flexible substrate with a larger value. Claim 14 In claim 1, the island further comprises a fixing portion formed to accommodate the electronic element, wherein the fixing portion is formed as a recess from the first surface toward the interior of the base, and the electronic element is fitted into the fixing portion, forming a flexible substrate. Claim 15 In claim 1, the island is disposed inside the elastic matrix, and the elastic matrix is ​​formed to surround the electronic element and the island, forming an elastic substrate.

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