Stretchable devices, display panels, sensors, and electronic devices

Abstract

The present invention relates to stretchable devices, display panels, sensors, and electronic devices. A stretchable device includes a stretchable substrate including a first elastomer, a plurality of unit devices on the stretchable substrate, a connection line configured to electrically connect adjacent unit devices, and a plurality of auxiliary structures each including a second elastomer and each at least partially overlapping at least one unit device or the connection line, wherein the first elastomer and the second elastomer are separate respective polymers that collectively include at least one structural unit.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2020-0093154, filed in the Korean Intellectual Property Office on July 27, 2020, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] Stretchable devices, display panels, sensors, and electronic devices are disclosed. BACKGROUND

[0004] Recently, attachable devices that attach display devices or biometric devices, such as smart skin devices, soft robots, and biomedical devices, directly to the skin or clothes have been researched. The attachable devices need stretchability to flexibly respond to the motion of a living body and to return to their original state. SUMMARY

[0005] Some example embodiments provide a stretchable device capable of reducing or preventing damage to the device by stretching.

[0006] Some example embodiments provide a display panel including the stretchable device.

[0007] Some example embodiments provide a sensor including the stretchable device.

[0008] Some example embodiments provide an electronic device including the stretchable device, the display panel, or the sensor.

[0009] According to some example embodiments, a stretchable device includes a stretchable substrate including a first elastomer, a plurality of unit devices on the stretchable substrate, a connection line configured to electrically connect adjacent unit devices of the plurality of unit devices, and a plurality of auxiliary structures. Each of the plurality of auxiliary structures can at least partially overlap at least one unit device of the plurality of unit devices and / or the connection line in a vertical direction perpendicular to an upper surface of the stretchable substrate, each of the plurality of auxiliary structures including a second elastomer. The first elastomer and the second elastomer can be separate respective (corresponding) polymers that collectively include at least one structural unit.

[0010] An elastic modulus of the second elastomer can be higher than an elastic modulus of the first elastomer.

[0011] An elastic modulus of the second elastomer can be higher than an elastic modulus of the first elastomer and lower than an elastic modulus of each separate unit device of the plurality of unit devices.

[0012] Each of the first elastomer and the second elastomer can be a thermoplastic elastomer.

[0013] The first and second elastomers can collectively belong to one of a styrene-containing polymer, an olefin-containing polymer, a urethane-containing polymer, or an ether-containing polymer.

[0014] The first elastomer can be a first copolymer comprising a hard structural unit of the first elastomer and a soft structural unit of the first elastomer. The second elastomer can be a second copolymer comprising a hard structural unit of the second elastomer and a soft structural unit of the second elastomer. The first and second elastomers can collectively comprise at least one hard structural unit.

[0015] The first and second elastomers can each collectively comprise a styrene-containing structural unit.

[0016] The soft structural unit of the first elastomer and the soft structural unit of the second elastomer can each comprise an ethylene structural unit, a propylene structural unit, a butylene structural unit, an isobutylene structural unit, a butadiene structural unit, an isoprene structural unit, or a combination thereof.

[0017] A weight ratio of the hard structural unit of the second elastomer to the soft structural unit of the second elastomer can be greater than a weight ratio of the hard structural unit of the first elastomer to the soft structural unit of the first elastomer.

[0018] A weight ratio of the hard structural unit of the first elastomer to the soft structural unit of the first elastomer can be less than about 1, and a weight ratio of the hard structural unit of the second elastomer to the soft structural unit of the second elastomer can be greater than about 1.

[0019] A weight ratio of the hard structural unit of the first elastomer to the soft structural unit of the first elastomer can be less than or equal to about 0.5, and a weight ratio of the hard structural unit of the second elastomer to the soft structural unit of the second elastomer can be greater than or equal to about 1.5.

[0020] Each auxiliary structure of the plurality of auxiliary structures can be under or over a lower surface or an upper surface of the stretchable substrate, or can be embedded in the stretchable substrate.

[0021] An area of each particular auxiliary structure can be greater than an area of a respective unit device of the plurality of unit devices that at least partially overlaps the particular auxiliary structure.

[0022] The plurality of unit devices can each comprise a light-emitting device, a light-absorbing device, a transistor, a resistive device, an imaging device, or a combination thereof.

[0023] According to some example embodiments, a stretchable device includes a stretchable substrate, a plurality of unit devices on the stretchable substrate, a connection line configured to electrically connect adjacent unit devices of the plurality of unit devices, and a plurality of auxiliary structures under or on or in the stretchable substrate. The plurality of auxiliary structures can at least partially overlap at least one unit device of the plurality of unit devices and / or the connection line in a vertical direction perpendicular to an upper surface of the stretchable substrate. The stretchable substrate can include a first copolymer including hard structural units and soft structural units. Each of the plurality of auxiliary structures can include a second copolymer including hard structural units and soft structural units. A weight ratio of the hard structural units of the second copolymer to the soft structural units of the second copolymer can be greater than a weight ratio of the hard structural units of the first copolymer to the soft structural units of the first copolymer.

[0024] A weight ratio of the hard structural units of the first copolymer to the soft structural units of the first copolymer can be less than about 1, and a weight ratio of the hard structural units of the second copolymer to the soft structural units of the second copolymer can be greater than about 1.

[0025] A weight ratio of the hard structural units of the first copolymer to the soft structural units of the first copolymer can be less than or equal to about 0.5, and a weight ratio of the hard structural units of the second copolymer to the soft structural units of the second copolymer can be greater than or equal to about 1.5.

[0026] The stretchable substrate and the plurality of auxiliary structures collectively include at least one same hard structural unit, and the at least one same hard structural unit includes a styrene-containing structural unit.

[0027] The soft structural units of the second copolymer and the soft structural units of the first copolymer can each include ethylene structural units, propylene structural units, butylene structural units, isobutylene structural units, butadiene structural units, isoprene structural units, or a combination thereof.

[0028] The stretchable substrate and the plurality of auxiliary structures can each include one of: styrene-ethylene-butylene-styrene SEBS, styrene-ethylene-propylene-styrene SEPS, styrene-butadiene-styrene SBS, styrene-isoprene-styrene SIS, styrene-isobutylene-styrene SIBS, or a combination thereof.

[0029] According to some example embodiments, a display panel including the stretchable device is provided.

[0030] According to some example embodiments, a sensor including the stretchable device is provided.

[0031] According to some example embodiments, an electronic device including the stretchable device, a display panel, or a sensor is provided.

[0032] The stretchable device can effectively reduce or prevent damage caused by stretching. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a plan view showing an arrangement of a stretchable device according to some example embodiments,

[0034] Figure 2 is a cross-sectional view of the stretchable device of Figure 1 taken along line II-II',

[0035] Figure 3 is a cross-sectional view of an enlarged portion A of Figure 2

[0036] Figure 4 is a schematic view showing an example of a skin-like display panel according to some example embodiments,

[0037] Figure 5A , 5B and 5C, and Figure 6 is a schematic view showing an example of a biometric sensor according to some example embodiments,

[0038] Figure 7 is a schematic view showing an example of a health care (health) device according to some example embodiments,

[0039] Figure 8 is a graph showing a distribution of strain on a wire and a light emitting device of a stretchable device according to an example, and

[0040] Figure 9 is a graph showing a change in an electrical property of a wire when a stretchable device according to an example is repeatedly stretched. DETAILED DESCRIPTION

[0041] Hereinafter, example implementations will be described in detail so that those having ordinary skill in the art can easily carry them out. However, structures for practical applications can be implemented in various different forms, and are not limited to the example implementations described herein.

[0042] In the drawings, the thicknesses of layers, films, panels, regions, and the like are exaggerated for clarity.

[0043] ​It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements can also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present.

[0044] Hereinafter, "substituted" as used herein, when not otherwise defined, means that a hydrogen of a compound or functional group is replaced with a substituent selected from a halogen atom, a hydroxyl group, an alkoxy group, a nitro group, a cyano group, an amino group, an azido group, a guanidine group, a hydrazine group, a hydrazone group, a carbonyl group, a carbamoyl group, a thiol group, an ester group, a carboxyl group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a silyl group, a Ci to C20 alkyl group, a C2 to C20 alkenyl group, a C2 to C20 alkynyl group, a C6 to C30 aryl group, a C7 to C30 aralkyl group, a Ci to C30 alkoxy group, a Ci to C20 heteroalkyl group, a C3 to C20 heteroaryl group, a C3 to C20 heteroaralkyl group, a C3 to C30 cycloalkyl group, a C3 to C15 cycloalkenyl group, a C6 to C15 cycloalkynyl group, a C3 to C30 heterocycloalkyl group, and combinations thereof.

[0045] Hereinafter, "combination" means a mixture or a stacked structure of two or more.

[0046] It will be understood that an element and / or a property thereof (e.g., structure, surface, direction, etc.) that is referred to as "vertical," "parallel," "coplanar," etc. with respect to another element and / or a property thereof can be "vertical," "parallel," "coplanar," etc. with respect to the other element and / or a property thereof, respectively, or "substantially vertical," "substantially parallel," "substantially coplanar."

[0047] An element and / or a property thereof (e.g., structure, surface, direction, etc.) that is referred to as "substantially vertical" with respect to another element and / or a property thereof will be understood to be "vertical" with respect to the other element and / or a property thereof within manufacturing and / or material tolerances, and / or to have a deviation in magnitude and / or angle from "vertical" with respect to the other element and / or a property thereof that is equal to or less than 10% (a tolerance of ±10%).

[0048] An element and / or a property thereof (e.g., structure, surface, direction, etc.) that is referred to as "substantially parallel" with respect to another element and / or a property thereof will be understood to be "parallel" with respect to the other element and / or a property thereof within manufacturing and / or material tolerances, and / or to have a deviation in magnitude and / or angle from "parallel" with respect to the other element and / or a property thereof that is equal to or less than 10% (a tolerance of ±10%).

[0049] "substantially coplanar" to other elements and / or properties thereof, and / or having a deviation in magnitude and / or angle from "coplanar" to other elements and / or properties thereof that is equal to or less than 10% (a tolerance of ±10%).

[0050] It will be understood that elements and / or properties thereof can be recited herein as being "the same as" or "equal to" other elements, and it will be further understood that elements and / or properties recited herein as being "the same as" or "equal to" other elements can be "the same as" or "equal to" or "substantially the same as" or "substantially equal to" other elements and / or properties thereof. Elements and / or properties that are "substantially the same as" or "substantially equal to" other elements and / or properties thereof will be understood to include elements and / or properties that are the same as or equal to other elements and / or properties thereof within manufacturing and / or material tolerances. Elements and / or properties that are the same as or substantially the same as other elements and / or properties thereof can be structurally the same as or substantially the same as, functionally the same as or substantially the same as, and / or compositionally the same as or substantially the same as.

[0051] It will be understood that elements and / or properties described herein as being "substantially" the same include elements and / or properties having a relative difference in magnitude equal to or less than 10%. Furthermore, whether elements and / or properties are modified as "substantially" or not, it will be understood that these elements and / or properties should be interpreted to include manufacturing or operational tolerances (e.g., ±10%) around the recited elements and / or properties.

[0052] When the term "about" or "substantially" is used in this specification in connection with a numerical value, it is intended that the associated numerical value include a tolerance of ±10% around the stated value. When a range is recited, the range includes all values therein, for example, in increments of 0.1%.

[0053] In the following, a stretchable device according to some example embodiments will be described with reference to the appended drawings.

[0054] Figure 1 is a plan view showing an arrangement of a stretchable device according to some example embodiments, Figure 2 is Figure 1 is a cross-sectional view of the stretchable device of Figure 3 is a cross-sectional view of an enlarged portion A of Figure 2

[0055] Reference is made to Figure 1 and 2 ​The stretchable device 100 according to some example embodiments includes a substrate 110, a plurality of unit devices 300 disposed on the substrate 110, and a connection line 121 configured to connect the plurality of unit devices 300, and a plurality of auxiliary structures 210.

[0056] The substrate 110 can be a stretchable substrate that can be stretched in a certain (or, alternatively, predetermined) direction and restored again. The substrate 110 can include a first elastic body having elasticity, which will be described later. The substrate 110 can be, for example, a light-transmissive (e.g., at least partially transparent) substrate.

[0057] The plurality of unit devices 300 are arranged on the substrate 110, for example, along rows and / or columns, forming an array 300A. The plurality of unit devices 300 can be, for example, arranged as a Bayer matrix, a PenTile matrix, a diamond matrix, or the like, but are not limited thereto. The plurality of unit devices 300 can be the same as or different from each other, and each unit device 300 can each include, for example, a light-emitting device such as an organic light-emitting diode, an inorganic light-emitting diode, a quantum dot light-emitting diode, a micro light-emitting diode, or a perovskite light-emitting diode; a light-absorbing device such as a photoelectric conversion device; a transistor such as a thin film transistor; a resistive device; an imaging device, or a combination thereof, but is not limited thereto. Each unit device 300 can include a conductor such as an electrode, a semiconductor such as an active layer (an active layer), an insulator, or the like, but is not limited thereto.

[0058] For example, each unit device 300 can be a light-emitting device configured to independently display light including a red wavelength spectrum, a green wavelength spectrum, a blue wavelength spectrum, or a combination thereof. For example, the light-emitting device can include a pair of electrodes and a light-emitting layer between the pair of electrodes and configured to emit light in the red wavelength spectrum, the green wavelength spectrum, the blue wavelength spectrum, or the combination thereof. For example, each unit device 300 can be a light-absorbing device configured to absorb light in a red wavelength spectrum, a green wavelength spectrum, a blue wavelength spectrum, an infrared wavelength spectrum, or a combination thereof. For example, the light-absorbing device can include a pair of electrodes and a light-absorbing layer between the pair of electrodes and configured to absorb light in the red wavelength spectrum, the green wavelength spectrum, the blue wavelength spectrum, the infrared wavelength spectrum, or the combination thereof. For example, the plurality of unit devices 300 can include a plurality of light-emitting devices and a plurality of light-absorbing devices alternately arranged along rows and / or columns.

[0059] For example, each unit device 300 can include at least one thin film transistor. The thin film transistor can include, for example, a switching transistor and / or a driving transistor. The switching transistor can be electrically connected to a gate line and a data line, and can include a first gate electrode connected to the gate line, a first source electrode connected to the data line, a first drain electrode facing the first source electrode, and a first semiconductor electrically connected to the first source electrode and the first drain electrode. The driving transistor can include a second gate electrode electrically connected to the first drain electrode, a second source electrode connected to a driving voltage line, a second drain electrode facing the second source electrode, and a second semiconductor electrically connected to the second source electrode and the second drain electrode. For example, the first semiconductor and the second semiconductor can individually include a semiconductor material and an elastomer. For example, the first semiconductor and the second semiconductor can include an organic semiconductor material and an elastomer.

[0060] In the drawings, all unit devices 300 have the same size, but are not limited thereto, and at least one unit device 300 can be larger or smaller than the other unit devices 300. In the drawings, all unit devices 300 have the same shape, but are not limited thereto, and at least one unit device 300 can have a different shape from the other unit devices 300.

[0061] The connection lines 121 (for example, each connection line 121) can be provided between adjacent unit devices 300 of the plurality of unit devices, and thus can be configured to electrically connect the adjacent unit devices 300. In some example embodiments, separate respective connection lines 121 can be included in the stretchable device 100 between and configured to electrically connect adjacent unit devices 300. The connection lines 121 can be one or at least two, and arranged in a row direction (for example, an x direction) and a column direction (for example, a y direction) between the unit devices 300 arranged along the row and / or the column. The connection lines 121 can be connected to a signal line (not shown), and the signal line can include, for example, a gate line that transmits a gate signal (or a scan signal), a data line that transmits a data signal, a driving voltage line that applies a driving voltage, and / or a common voltage line that applies a common voltage, but is not limited thereto. The connection lines 121 can include, for example, a low-resistance conductor such as silver, gold, copper, aluminum, or an alloy thereof.

[0062] Each auxiliary structure 210 of the plurality of auxiliary structures 210 can be an island structure at least partially overlapping (for example, in a z direction) the unit device 300 and / or the connection line 121, and the plurality of auxiliary structures 210 can be spaced apart to be provided at a specific (or alternatively predetermined) gap (for example, spacing) between adjacent auxiliary structures 210 (establishing a specific (or alternatively predetermined) gap (for example, spacing) between adjacent auxiliary structures 210), for example, as shown in at least Figures 1-2 FIG. 2B.

[0063] For example, auxiliary structures 210 may be arranged to correspond to unit devices 300, e.g., along rows and / or columns. In some exemplary embodiments, and as at least Figures 1-2 As shown, each auxiliary structure 210 may at least partially overlap with at least one of the multiple unit devices 300 and / or with the connecting line 121 (e.g., in the z-direction). Figure 2 As shown, the z-direction may be perpendicular to the upper surface 110a of the substrate 110. For example, auxiliary structures 210 may overlap with unit devices 300 (e.g., in the z-direction) and be arranged on a portion of the connecting line 121 (e.g., overlapping in the z-direction), and therefore, the area of ​​the auxiliary structures 210 (e.g., the area of ​​each specific auxiliary structure 210 in the xy plane) may be larger than the area of ​​the unit devices 300 (e.g., larger than the area of ​​each corresponding unit device 300 that at least partially overlaps with the specific auxiliary structure 210 in the z-direction in the xy plane). For example, the auxiliary structures 210 may be arranged randomly (randomly).

[0064] In the attached figure ( Figures 1-2 In this embodiment, each auxiliary structure 210 is disposed below the individual unit device 300 and the connecting line 121 (e.g., at least partially overlapping in the z-direction), but not limited thereto, and may be disposed on the unit device 300 and the connecting line 121. Furthermore, in the figures, each auxiliary structure 210 is disposed within the substrate 110, but not limited thereto, and may be disposed on or below the substrate 110. Each of the plurality of auxiliary structures 210 may be below or above the substrate 110, or may be embedded in the substrate 110. The auxiliary structure 210 may be below, above, or inside the substrate 110.

[0065] The stiffness of the auxiliary structure 210 may differ from the stiffness of the substrate 110, the unit device 300, and the connecting line 121. Here, stiffness represents the degree of resistance to deformation when an external force is applied. A relatively high stiffness indicates a relatively high resistance to deformation and therefore relatively small deformation, while a relatively low stiffness indicates a relatively low resistance to deformation and therefore relatively large deformation. Specifically, the stiffness of the auxiliary structure 210 may be relatively higher than the stiffness of the substrate 110 and relatively lower than the stiffness of the unit device 300 and the connecting line 121. Stiffness can be evaluated by the elastic modulus, where a high elastic modulus indicates high stiffness, and a low elastic modulus indicates low stiffness. The elastic modulus may be, for example, Young's modulus.

[0066] Each auxiliary structure 210 can include a second elastic body. The second elastic body can have an elastic modulus higher than that of the first elastic body included in the substrate 110. Reiterating, the elastic modulus of the second elastic body can be higher than that of the first elastic body. For example, the elastic modulus of the second elastic body can be greater than or equal to about 50 times, within the range, greater than or equal to about 80 times, greater than or equal to about 100 times, greater than or equal to about 150 times, greater than or equal to about 200 times, for example, about 50 times to about 100,000 times, about 80 times to about 100,000 times, about 100 times to about 100,000 times, about 150 times to about 100,000 times, or about 200 times to about 100,000 times, but not limited thereto. For example, the elastic modulus of the first elastic body can be greater than or equal to about 10 2 Pa and less than about 10 7 Pa, and the elastic modulus of the second elastic body can be about 10 7 Pa to about 10 10 Pa, but not limited thereto. In some example embodiments, the elastic modulus of the second elastic body can be lower than that of each individual unit device 300 including an electrode and a component such as a metal and / or the connection line 121 (e.g., ≥ 10 12 Pa). Reiterating, the elastic modulus of the second elastic body can be higher than that of the first elastic body and can be lower than that of each individual unit device 300 of the plurality of unit devices 300 and / or the elastic modulus of the second elastic body can be lower than that of the plurality of unit devices 300 and / or the connection line 121.

[0067] The difference in the elastic modulus of the first elastic body and the second elastic body can result in a difference in the elastic modulus of the substrate 110 and the auxiliary structure 210, and the elongation of the auxiliary structure 210 can be lower than that of the substrate 110. Here, the elongation can be the percentage of the change in length up to the breaking point with respect to the initial length.

[0068] For example, the elongation of the auxiliary structure 210 can be less than or equal to about 100%, and within the range, about 10% to about 100%, about 15% to about 100%, about 20% to about 100%, about 10% to about 80%, about 15% to about 80%, about 20% to about 80%, about 10% to about 50%, about 15% to about 50%, about 20% to about 50%, about 10% to about 40%, about 15% to about 40%, or about 20% to about 40%.

[0069] For example, the elongation of the substrate 110 can be greater than or equal to about 200%, and within the range, greater than or equal to about 250%, greater than or equal to about 300%, or greater than or equal to about 500%, for example, about 200% to about 1000%, about 250% to about 1000%, about 300% to about 1000%, or about 500% to about 1000%.

[0070] For example, the first and second elastomers can each be (e.g., can each be) a thermoplastic elastomer. The first and second elastomers can each be a polymer including a plurality of structural units that are the same as or different from each other, and including at least one common structural unit (e.g., at least one identical structural unit) among them. Restated, the first and second elastomers can be separate respective polymers that collectively include (e.g., each include) at least one identical structural unit. For example, the first and second elastomers can include two types of structural units, and collectively include one or both types of structural units among them. For example, the first and second elastomers can include three types of structural units, and collectively include one, two, or three types of structural units.

[0071] In this way, the first and second elastomers collectively include (e.g., can each include) at least one structural unit (e.g., at least one identical structural unit), and thus can reduce heterogeneity at the interface of the substrate 110 including the first elastomer and the auxiliary structure 210 including the second elastomer, and at the same time, increase the adhesion performance of the interface of the substrate 110 and the auxiliary structure 210 due to the thermoplastic properties of the first and second elastomers by chemical bonds, for example, cross-linking bonds, between the first and second elastomers at or above the glass transition temperature (Tg) or the melting point (Tm). Accordingly, separation or detachment of the auxiliary structure 210 from the substrate 110 can be prevented when the stretchable device 100 or the substrate 110 is elongated.

[0072] In some example embodiments, the substrate 110 and the auxiliary structure 210 can be formed by coating and drying a solution including the first elastomer and a solution including the second elastomer, respectively, wherein the solution including the first elastomer and the solution including the second elastomer can further include a hardening agent, for example, a photo-hardening agent and / or a thermal hardening agent, and thus improve chemical resistance, and at the same time, further facilitate chemical bonds, for example, cross-linking bonds, of the first and second elastomers, and thus further improve the adhesion performance of the interface of the substrate 110 and the auxiliary structure 210.

[0073] For example, the first and second elastomers can independently be a copolymer including at least one hard structural unit providing a relatively hard property and at least one soft structural unit providing a relatively soft property. Restated, the first elastomer can be a first copolymer including a hard structural unit of the first elastomer and a soft structural unit of the first elastomer, and the second elastomer can be a second copolymer including a hard structural unit of the second elastomer and a soft structural unit of the second elastomer. The first and second elastomers can collectively include (e.g., each include) at least one same hard structural unit. Restated, the substrate 110 and the auxiliary structures 210 can each include at least one same hard structural unit, which can include, for example, a styrene-containing structural unit.

[0074] The substrate 110 and the auxiliary structures 210 can each independently include a copolymer including a hard structural unit and a soft structural unit. Restated, the substrate 110 can include a first copolymer including a hard structural unit of the stretchable substrate and a soft structural unit of the stretchable substrate. The auxiliary structures 210 can each include a second copolymer including a hard structural unit of the plurality of auxiliary structures and a soft structural unit of the plurality of auxiliary structures.

[0075] The first and second copolymers can include the same or different copolymers.

[0076] The hard structural unit can provide, for example, plastic properties such as high-temperature performance, thermoplastic processability, tensile strength, and tear strength, and the soft structural unit can provide, for example, elastic properties such as low-temperature performance, hardness, flexibility, and tensile / compression. By appropriately setting the hard structural unit and the soft structural unit, the first and second elastomers can exhibit thermoplastic elastomeric properties. The hard structural unit and the soft structural unit can be alternately arranged or arranged as clusters or blocks in the first and second elastomers.

[0077] For example, the hard structural unit can include, for example, a styrene-containing structural unit, an olefin-containing structural unit, a urethane-containing structural unit, an ether-containing structural unit, or a combination thereof, but is not limited thereto. For example, the soft structural unit can include, for example, an ethylene structural unit, a propylene structural unit, a butylene structural unit, an isobutylene structural unit, a butadiene structural unit, an isoprene structural unit, or a combination thereof, but is not limited thereto.

[0078] For example, the first elastomer and the second elastomer can collectively include at least one hard structural unit (e.g., can each include the same unit of at least one hard structural unit), such as collectively including (e.g., each including the same unit of) a styrene-containing structural unit, an olefin-containing structural unit, a urethane-containing structural unit, an ether-containing structural unit, or a combination thereof. Thus, the first elastomer and the second elastomer can collectively belong to (e.g., can collectively include) one of a styrene-containing polymer, an olefin-containing polymer, a urethane-containing polymer, or an ether-containing polymer. Restated, the first elastomer and the second elastomer can include (e.g., can each include) the same material, which is one of a styrene-containing polymer, an olefin-containing polymer, a urethane-containing polymer, or an ether-containing polymer. For example, the soft structural unit of the auxiliary structure 210 and the soft structural unit of the substrate 110 can each include an ethylene structural unit, a propylene structural unit, a butene structural unit, an isobutylene structural unit, a butadiene structural unit, an isoprene structural unit, or a combination thereof.

[0079] For example, the first elastomer and the second elastomer can collectively include a styrene-containing structural unit as a hard structural unit, and also include the same or different soft structural unit.

[0080] For example, the first elastomer and the second elastomer can collectively include a styrene-containing structural unit as its respective hard structural unit, and also include an ethylene structural unit, a propylene structural unit, a butene structural unit, an isobutylene structural unit, a butadiene structural unit, an isoprene structural unit, or a combination thereof as its respective soft structural unit. Partially restated, the soft structural unit of the first elastomer and the soft structural unit of the second elastomer each include the same or different structural unit, which includes an ethylene structural unit, a propylene structural unit, a butene structural unit, an isobutylene structural unit, a butadiene structural unit, an isoprene structural unit, or a combination thereof.

[0081] For example, the first elastomer and the second elastomer can be styrene-containing polymers. For example, the first elastomer and the second elastomer can independently include one selected from the group consisting of styrene-ethylene-butylene-styrene SEBS, styrene-ethylene-propylene-styrene SEPS, styrene-butadiene-styrene SBS, styrene-isoprene-styrene SIS, styrene-isobutylene-styrene SIBS, and combinations thereof.

[0082] For example, one of the first or second elastomers can include styrene-ethylene-butylene-styrene SEBS, and the other of the first or second elastomers can include one selected from the group consisting of styrene-ethylene-butylene-styrene SEBS, styrene-ethylene-propylene-styrene SEPS, styrene-butadiene-styrene SBS, styrene-isoprene-styrene SIS, styrene-isobutylene-styrene SIBS, and combinations thereof. For example, the substrate 110 and the auxiliary structure 210 can each include one of styrene-ethylene-butylene-styrene SEBS, styrene-ethylene-propylene-styrene SEPS, styrene-butadiene-styrene SBS, styrene-isoprene-styrene SIS, styrene-isobutylene-styrene SIBS, or combinations thereof.

[0083] For example, the first elastomer can include styrene-ethylene-butylene-styrene SEBS, and the second elastomer can include one selected from the group consisting of styrene-ethylene-butylene-styrene SEBS, styrene-ethylene-propylene-styrene SEPS, styrene-butadiene-styrene SBS, styrene-isoprene-styrene SIS, styrene-isobutylene-styrene SIBS, and combinations thereof.

[0084] For example, the first and second elastomers can each individually include styrene-ethylene-butylene-styrene SEBS.

[0085] In some example embodiments, the first and second elastomers can have an elastic modulus by controlling a ratio of hard structural units and soft structural units, as described above.

[0086] For example, a weight ratio of hard structural units to soft structural units of the second elastomer (e.g., of the plurality of auxiliary structures 210) can be greater than (e.g., higher than) a weight ratio of hard structural units to soft structural units of the first elastomer (e.g., of the substrate 110), and thus, the second elastomer can have an elastic modulus that is higher than an elastic modulus of the first elastomer. For example, the weight ratio of hard structural units to soft structural units of the second elastomer can be greater than or equal to about two times, about 3 times, about 4 times, about 5 times, about 7 times, or about 10 times the weight ratio of hard structural units to soft structural units of the first elastomer.

[0087] For example, the weight ratio of hard structural units to soft structural units of the second elastomer (e.g., of the second elastomer of the plurality of secondary structure bodies 210) can be greater than (e.g., higher than) about 1, and within the range, greater than or equal to about 1.1, greater than or equal to about 1.2, greater than or equal to about 1.3, greater than or equal to about 1.4, greater than or equal to about 1.5, greater than or equal to about 1.7, greater than or equal to about 1.9, or greater than or equal to about 2.0 and less than or equal to about 9.9, about 1.1 to about 9.9, about 1.2 to about 9.9, about 1.3 to about 9.9, about 1.4 to about 9.9, about 1.5 to about 9.9, about 1.7 to about 9.9, about 1.9 to about 9.9, or about 2.0 to about 9.9.

[0088] For example, the weight ratio of hard structural units to soft structural units of the first elastomer (e.g., of the substrate 110) can be less than (e.g., lower than) about 1, and within the range, less than or equal to about 0.9, less than or equal to about 0.8, less than or equal to about 0.7, less than or equal to about 0.6, less than or equal to about 0.5, less than or equal to about 0.4, or less than or equal to about 0.3, about 0.01 to about 0.9, about 0.01 to about 0.8, about 0.01 to about 0.7, about 0.01 to about 0.6, about 0.01 to about 0.5, about 0.01 to about 0.4, or about 0.03 to about 0.01.

[0089] For example, the weight ratio of hard structural units to soft structural units of the second elastomer can be greater than or equal to about 1.2, and the weight ratio of hard structural units to soft structural units of the first elastomer can be less than or equal to about 0.7.

[0090] For example, the weight ratio of hard structural units to soft structural units of the second elastomer can be greater than or equal to about 1.5, and the weight ratio of hard structural units to soft structural units of the first elastomer can be less than or equal to about 0.5.

[0091] In this way, the first and second elastomers are adjusted to have different ratios of hard structural units to soft structural units, such that the substrate 110 and the secondary structure bodies 210 can have a desired (e.g., specific) modulus of elasticity.

[0092] Reference Figure 3When the substrate 110 is elongated in one direction (e.g., the x direction), due to the large difference in the elastic modulus of the substrate 110 and the unit device 300 / connection line 121, a high strain can be applied to the unit device 300 / connection line 121. In particular, stress (strain) can be concentrated at a specific location, such as the contact portion of the unit device 300 and the connection line 121. The auxiliary structure 210 has an elastic modulus greater than that of the substrate 110 but less than that of the unit device 300 / connection line 121, and thus, when the substrate 110 is elongated, the stress (strain) applied to the unit device 300 / connection line 121 can be gently dispersed, and thus, damage to the unit device 300 / connection line 121 due to breakage, cracking, etc. can be prevented.

[0093] Accordingly, the stretchable device 100 according to some example embodiments can flexibly respond to external force or external motion of the substrate in a specific (or, alternatively, predetermined) direction, such as twisting, pressing, and pulling, and at the same time, effectively prevent separation or detachment of the substrate 110 from the auxiliary structure 210 due to the external force or external motion, and in addition, can prevent concentration of stress (strain) at a specific location, such as the contact portion of the stretchable device 300 and the connection line 121, by gently dispersing the stress (strain) applied to the unit device 300 / connection line 121, and can effectively reduce or prevent damage to the stretchable device 300 and / or the connection line 121 by adjusting the elastic modulus of the auxiliary structure 210 and thus, smoothly (gently) dispersing the stress (strain) applied to the stretchable device 300 and / or the connection line 121.

[0094] The stretchable device 100 described above can be applied to (e.g., included in) various devices requiring stretchability, such as a bendable display panel, a foldable display panel, a rollable display panel, a wearable device, a skin-like display panel, a skin-like sensor, a large-area conformable display, a smart clothing, etc., but is not limited thereto.

[0095] For example, the stretchable device 100 described above can be included in a skin-like display panel.

[0096] Figure 4 FIG. 1 is a schematic view showing an example of a skin-like display panel according to some example embodiments.

[0097] The stretchable device 100 can be a skin-like display panel (ultra-thin display panel) (e.g., can be included therein), and thus be used by being attached to a part of a living body, e.g., a hand. The skin-like display panel can display specific (or alternatively predetermined) information, e.g., various letters and / or images. The skin-like display panel can include, e.g., a light emitting device such as an inorganic light emitting diode, a micro light emitting diode, an organic light emitting diode (OLED), a quantum dot light emitting diode, or a perovskite light emitting diode as the aforementioned unit device 300, but is not limited thereto.

[0098] For example, the above-described stretchable device 100 can be included in a sensor, e.g., a biometric sensor.

[0099] Figure 5A 5B and 5C, and Figure 6 are schematic diagrams showing examples of a biometric sensor according to some example embodiments.

[0100] The stretchable device 100 can be a wearable biometric sensor (e.g., can be included therein), and can be attached to a surface of a living body, e.g., skin, a living body, e.g., an organ, or an indirect means for contacting a living body, e.g., clothing, to detect and measure biological information, e.g., a biological signal. For example, the biometric sensor can include an electroencephalogram (EEG) sensor, an electrocardiogram (ECG) sensor, a blood pressure (BP) sensor, an electromyogram (EMG) sensor, a blood glucose (BG) sensor, a photoplethysmogram (PPG) sensor, an accelerometer, an RFID antenna, an inertial sensor, an activity sensor, a strain sensor, a motion sensor, or a combination of these, but is not limited thereto. The biometric sensor can be attached to a living body in a very thin patch type or band type form, so that biological information can be monitored in real time.

[0101] The stretchable device 100 can include a light emitting device 310 and a light absorbing device 320 as the aforementioned unit device 300. The light emitting device 310 can be configured to emit first light L1 for sensing a biological signal. The light emitting device 310 can be, e.g., an infrared light emitting diode configured to emit the first light L1 in an infrared wavelength spectrum or a visible light emitting diode configured to emit the first light L1 in a visible wavelength spectrum. The first light L1 emitted from the light emitting device 310 can be reflected by or absorbed in an object 400 (e.g., a body such as skin or a blood vessel).

[0102] The light absorbing device 320 can be configured to absorb second light L2 reflected by the object 400 from the first light L1 emitted from the light emitting device 300, and convert the absorbed light into an electrical signal. The electrical signal converted by the reflected second light L2 can include body information. The electrical signal including biometric information can be transmitted to a sensor IC (not shown) or a processor (not shown).​

[0103] As an example, the stretchable device 100 can be a photoplethysmography (PPG) sensor, and the bio-information can include a heart rate, an oxygen saturation, a stress (pressure, stress), an arrhythmia, a blood pressure, etc., and can be obtained by analyzing a waveform of an electrical signal.

[0104] For example, the stretchable device 100 can be an electromyography (EMG) sensor or a strain sensor attached to a joint for a rehabilitation treatment of a patient having a joint and muscle problem. The EMG sensor or the strain sensor can be attached to a desired site to quantitatively measure a muscle movement or a joint movement to secure data necessary for rehabilitation.

[0105] The aforementioned stretchable device, display panel, or sensor can be included in various electronic devices, and the electronic device can further include a processor (not shown) and a memory (not shown). The electronic device can be a mobile phone, a TV, a health care device, etc., and the health care device can include, for example, a photoplethysmography (PPG) sensor, an electroencephalogram (EEG) sensor, an electrocardiogram (ECG) sensor, a blood pressure (BP) sensor, an electromyography (EMG) sensor, a blood glucose (BG) sensor, an accelerometer, an RFID antenna, an inertial sensor, an activity sensor, a strain sensor, a motion sensor, or a combination thereof, but is not limited thereto.

[0106] Figure 7 FIG. 1 is a schematic diagram illustrating an example of a health care device according to some example embodiments.

[0107] Reference Figure 7 According to some example embodiments, a health care device 1000 (e.g., an electronic device) can be a patch-type or a band-type attachable health care device, and include the aforementioned stretchable device 100, an IC and / or a processor 600 for processing a bio-signal obtained from the stretchable device 100, and a display area 700 for displaying the obtained bio-signal as various letters and / or images.

[0108] Hereinafter, some example embodiments will be explained in more detail with reference to one or more embodiments. However, the current scope of the example embodiments is not limited to the described embodiments.

[0109] Manufacture of stretchable devices

[0110] Embodiments

[0111] A polymer solution for an auxiliary structure was prepared by dissolving styrene-ethylene-butylene-styrene SEBS (H1043, Asahi Kasei Corp.) including styrene structural units and ethylene / butylene structural units at a ratio of 67:33 (w / w) and a hardener (azide crosslinking agent [bis(6-((4-azido-2,3,5,6-tetrafluorobenzoyl)oxy)hexyl) sebacate]) in toluene. In the polymer solution for an auxiliary structure, SEBS and the hardener were included at a weight ratio of 100:4.5. Then, the polymer solution for an auxiliary structure was coated on a glass substrate having a sacrificial layer, and then dried, cured, and patterned to form a plurality of auxiliary structures having a thickness of 5 μm (elongation: about 20%, elastic modulus: about 80 MPa). Subsequently, a polymer solution for a stretchable substrate was prepared by dissolving styrene-ethylene-butylene-styrene SEBS (H1052, Asahi Kasei Corp.) including styrene structural units and ethylene / butylene structural units at a ratio of 20:80 (w / w) and a hardener (azide crosslinking agent [bis(6-((4-azido-2,3,5,6-tetrafluorobenzoyl)oxy)hexyl) sebacate]) in toluene. In the polymer solution for a stretchable substrate, SEBS and the hardener were included at a weight ratio of 100:3. Then, the polymer solution for a stretchable substrate was coated on the plurality of auxiliary structures and dried to form a stretchable substrate of 2.5 μm (elongation: 700%, elastic modulus: ~1 MPa). Subsequently, on the stretchable substrate, a positive electrode and an Au line electrically connected thereto were formed by photolithography to at least partially overlap the plurality of auxiliary structures, and further a light emitting device having a stacked structure of a positive electrode / hole injection layer (HIL) / organic light emitting layer / electron injection layer (EIL) / negative electrode was formed, and thus a stretchable device was manufactured. Subsequently, the sacrificial layer was removed to separate the stretchable device from the glass substrate.

[0112] Comparative Example 1

[0113] A stretchable device was manufactured according to the same method as in the example, except that the plurality of auxiliary structures was not formed.

[0114] Comparative Example 2

[0115] On a polydimethylsiloxane (PDMS) substrate (elongation: about 200%, elastic modulus: about 40 MPa), a precursor solution for polyimide was coated and cured to form a polyimide layer. Subsequently, the polyimide layer was patterned by photolithography to form a plurality of polyimide structures (elongation: about 5%, elastic modulus: about 1 GPa). Subsequently, a positive electrode and an Au wire electrically connected thereto were formed on the polyimide structures by photolithography, and further a light emitting device having a stacked structure of positive electrode / hole injection layer (HIL) / organic light emitting layer / electron injection layer (EIL) / negative electrode was formed to manufacture a stretchable device.

[0116] Evaluation

[0117] Evaluation I

[0118] The adhesion strength between the stretchable substrate and the auxiliary structure in the stretchable device according to the example and the adhesion strength between the PDMS substrate and the polyimide structure in the stretchable device according to Comparative Example 2 were evaluated by t-peel test. Also, the stretchable devices according to the example and the comparative examples were elongated by 20% in both sides (x direction) to evaluate whether the stretchable devices were damaged.

[0119] Whether the stretchable device was damaged was evaluated by checking whether the stretchable device was separated due to detachment after elongation and whether the interface of the light emitting device and the Au wire was damaged.

[0120] The results are shown in Table 1.

[0121] Table 1

[0122] Bonding strength (N / mm) Delamination Short circuit Cracking Examples 0.187 X X X Comparative Example 1 - - ○ ○ Comparative Example 2 0.01 ○ ○ X

[0123] Referring to Table 1, the adhesion strength between the stretchable substrate and the auxiliary structure in the stretchable device according to the example was greater than the adhesion strength between the PDMS substrate and the polyimide structure in the stretchable device according to Comparative Example 2. In addition, the stretchable device according to the example did not exhibit detachment after elongation and did not exhibit cracks and breaks at the interface of the light emitting device and the Au wire, but the stretchable device according to Comparative Example 2 exhibited detachment between the PDMS substrate and the polyimide structure after elongation, and the stretchable devices according to Comparative Examples 1 and 2 exhibited breaks and / or cracks at the interface of the light emitting device and the Au wire.

[0124] Evaluation II

[0125] The stretchable device according to the example was elongated by 10% in both sides (x direction) to perform a strain evaluation.

[0126] The results are shown in Figure 8 .

[0127] Figure 8 A graph showing the strain distribution acting on the wire and the light emitting device of the stretchable device according to the embodiment.

[0128] Reference Figure 8 When the stretchable device according to the embodiment is elongated by 10% in both sides (x direction), the strain hardly acts on the light emitting device, but is concentrated on the Au wire at both sides of the light emitting device. Therefore, since the strain generated during the elongation is directed to the Au wire, the stretchable device can stably work without deteriorating the light emitting device.

[0129] Evaluation III

[0130] When the stretchable device according to the embodiment is repeatedly elongated in both sides (x direction), the change in the electrical property of the Au wire is evaluated.

[0131] The electrical property of the Au wire is evaluated by using the resistance R according to the elongation rate in both sides and the change ratio R / R0 of the resistance R with respect to the initial resistance R0.

[0132] The results are shown in Figure 9 .

[0133] Figure 9 A graph showing the change in the electrical property of the wire when the stretchable device according to the embodiment is repeatedly stretched.

[0134] Reference Figure 9 , the stretchable device according to the embodiment exhibits a relatively constant resistance value through the repeated elongation. Therefore, in the stretchable device according to the embodiment, the wire is not damaged by the repeated elongation.

[0135] While the present disclosure has been described in connection with what is presently considered to be the best example embodiment, it is to be understood that the inventive concept is not limited to the disclosed example embodiments. On the contrary, the inventive concept is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A stretchable device comprising: a stretchable substrate comprising a first elastomer; a plurality of unit devices on the stretchable substrate; a connection line configured to electrically connect adjacent unit devices of the plurality of unit devices; and a plurality of auxiliary structures, each auxiliary structure of the plurality of auxiliary structures at least partially overlapping at least one unit device of the plurality of unit devices and / or the connection line in a vertical direction perpendicular to an upper surface of the stretchable substrate, each of the plurality of auxiliary structures comprising a second elastomer, wherein the first elastomer and the second elastomer are separate respective polymers that collectively comprise at least one structural unit, the first elastomer is a first copolymer comprising a hard structural unit of the first elastomer and a soft structural unit of the first elastomer, the second elastomer is a second copolymer comprising a hard structural unit of the second elastomer and a soft structural unit of the second elastomer, the hard structural unit of the first copolymer and the hard structural unit of the second copolymer independently comprise a styrene-containing structural unit, a urethane-containing structural unit, an ether-containing structural unit, or a combination thereof, the soft structural unit of the first copolymer and the soft structural unit of the second copolymer independently comprise an ethylene structural unit, a propylene structural unit, a butylene structural unit, an isobutylene structural unit, a butadiene structural unit, an isoprene structural unit, or a combination thereof, and a weight ratio of the hard structural unit of the second elastomer to the soft structural unit of the second elastomer is greater than a weight ratio of the hard structural unit of the first elastomer to the soft structural unit of the first elastomer.

2. The stretchable device of claim 1, wherein an elastic modulus of the second elastomer is higher than an elastic modulus of the first elastomer.

3. The stretchable device of claim 1, wherein an elastic modulus of the second elastomer is higher than an elastic modulus of the first elastomer, and an elastic modulus of the second elastomer is lower than an elastic modulus of each individual unit device of the plurality of unit devices.

4. The stretchable device of claim 1, wherein the first elastomer and the second elastomer are each a thermoplastic elastomer.

5. The stretchable device of claim 4, wherein the first elastomer and the second elastomer collectively belong to one of the following: a styrene-containing polymer, a urethane-containing polymer, or an ether-containing polymer.

6. The stretchable device of claim 1, wherein the first elastomer and the second elastomer collectively comprise at least one hard structural unit.

7. The stretchable device of claim 6, wherein the first elastomer and the second elastomer each collectively comprise a styrene-containing structural unit.

8. The stretchable device of claim 1, wherein a weight ratio of the hard structural unit of the first elastomer to the soft structural unit of the first elastomer is less than 1, and a weight ratio of the hard structural unit of the second elastomer to the soft structural unit of the second elastomer is greater than 1.

9. The stretchable device of claim 1, wherein ​ a weight ratio of hard structural units of the first elastomer to soft structural units of the first elastomer is less than or equal to 0.5, and a weight ratio of hard structural units of the second elastomer to soft structural units of the second elastomer is greater than or equal to 1.

5.

10. The stretchable device of claim 1, wherein each auxiliary structure of the plurality of auxiliary structures is under or over the stretchable substrate, or embedded in the stretchable substrate.

11. The stretchable device of claim 1, wherein an area of each particular auxiliary structure is greater than an area of a corresponding unit device of the plurality of unit devices that at least partially overlaps with the particular auxiliary structure.

12. The stretchable device of claim 1, wherein each unit device of the plurality of unit devices comprises a light emitting device, a light absorbing device, a transistor, a resistive device, an imaging device, or a combination thereof.

13. A stretchable device, comprising: a stretchable substrate; a plurality of unit devices on the stretchable substrate; connection lines configured to electrically connect adjacent unit devices of the plurality of unit devices; and a plurality of auxiliary structures under or over or inside the stretchable substrate, the plurality of auxiliary structures at least partially overlapping at least one unit device of the plurality of unit devices and / or the connection lines in a vertical direction perpendicular to an upper surface of the stretchable substrate, wherein the stretchable substrate comprises a first copolymer, the first copolymer comprising hard structural units and soft structural units, wherein each auxiliary structure of the plurality of auxiliary structures comprises a second copolymer, the second copolymer comprising hard structural units and soft structural units, and wherein a weight ratio of hard structural units of the second copolymer to soft structural units of the second copolymer is greater than a weight ratio of hard structural units of the first copolymer to soft structural units of the first copolymer, the hard structural units of the first copolymer and the hard structural units of the second copolymer independently comprise styrene-containing structural units, urethane-containing structural units, ether-containing structural units, or a combination thereof, and the soft structural units of the first copolymer and the soft structural units of the second copolymer independently comprise ethylene structural units, propylene structural units, butylene structural units, isobutylene structural units, butadiene structural units, isoprene structural units, or a combination thereof.

14. The stretchable device of claim 13, wherein a weight ratio of hard structural units of the first copolymer to soft structural units of the first copolymer is less than 1, and a weight ratio of hard structural units of the second copolymer to soft structural units of the second copolymer is greater than 1.

15. The stretchable device of claim 13, wherein a weight ratio of hard structural units of the first copolymer to soft structural units of the first copolymer is less than or equal to 0.5, and a weight ratio of hard structural units of the second copolymer to soft structural units of the second copolymer is greater than or equal to 1.

5.

16. The stretchable device of claim 13, wherein the stretchable substrate and the plurality of auxiliary structures collectively comprise at least one same hard structural unit, and the stretchable substrate and the plurality of auxiliary structures collectively comprise at least one same soft structural unit. The at least one identical hard building block comprises a styrene containing building block.

17. The stretchable device of claim 13, wherein the stretchable substrate and the plurality of secondary structures each comprise one of: styrene-ethylene-butylene-styrene (SEBS), styrene-ethylene-propylene-styrene (SEPS), styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), styrene-isobutylene-styrene (SIBS), or a combination thereof.

18. A display panel comprising the stretchable device of any one of claims 1-17.

19. A sensor comprising the stretchable device of any one of claims 1-17.

20. An electronic device comprising the display panel of claim 18 or the sensor of claim 19.

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