Stretchable touchscreen, method for manufacturing the same, and display device using the same
11287935 · 2022-03-29
Assignee
Inventors
Cpc classification
G06F3/0446
PHYSICS
G06F2203/04102
PHYSICS
H05K2201/0195
ELECTRICITY
G06F2203/04103
PHYSICS
H05K3/107
ELECTRICITY
International classification
H05K3/00
ELECTRICITY
Abstract
Disclosed are a stretchable touchscreen, a method for manufacturing the same and a display device including the same. After using a material having a high elastic restoring force as a substrate and determining regions where touch electrodes are formed by defining grooves thereon, touch electrodes are formed by filling the grooves with nanowires. Accordingly, it is possible to maintain elastic restoring force of the substrate and electrical connection between wires of nanowires, so that the touch electrode neither breaks nor factures despite being stretched any direction, and reliable stretchable touchscreens can be provided due to no resistance increase.
Claims
1. A stretchable touchscreen comprising: a stretchable substrate of a single layer having a modulus of 100 MPa to 200 MPa and a strain higher than 10%; a plurality of first grooves arranged in a first direction and defined by removing a first predetermined depth from a first surface of the stretchable substrate, wherein the first predetermined depth is from 1/200 to 1/10 of a thickness of the stretchable substrate; a plurality of first electrodes, each of the plurality of first electrodes including nanowires within each of the plurality of first grooves, wherein the nanowires connect each other in a form of a chain in each of the plurality of first grooves; gaps among the nanowires within each of the plurality of first grooves, wherein the gaps among the nanowires are changed by elongation of the stretchable substrate; and a protective film over the plurality of first electrodes, wherein an inner surface of the protective film is in coplanar contact with the first surface of the stretchable substrate and an upper surface of the nanowires included in each of the plurality of first electrodes.
2. The stretchable touchscreen according to claim 1, wherein the stretchable substrate is a silicone-based film or a polyurethane-based film.
3. The stretchable touchscreen according to claim 1, wherein the plurality of first grooves are parallel to each other and are disposed along the direction of one side of the stretchable substrate.
4. The stretchable touchscreen according to claim 1, wherein the protective film is an organic film for planarizing a surface.
5. The stretchable touchscreen according to claim 1, further comprising: a plurality of second electrodes disposed in a second direction crossing the first electrodes in the first direction on the protective film; and a plurality of first connection electrodes disposed in in the first direction and connecting adjacent ones of the first electrodes, the first connection electrodes not overlapping the second electrodes and disposed in the first direction, wherein the second electrodes and the first connection electrodes also include nanowires.
6. The stretchable touchscreen according to claim 5, wherein the protective film comprises a laminate of an organic film and an inorganic film.
7. The stretchable touchscreen according to claim 6, further comprising: a barrier film covering the second electrodes and the first connection electrodes on the protective film.
8. The stretchable touchscreen according to claim 1, further comprising: a plurality of second grooves on a second surface of the substrate with a second predetermined depth from the second surface of the substrate, the second surface of the substrate opposite the first surface of the substrate, the first grooves arranged in a first direction and the second grooves arranged in a second direction crossing the first direction; and a plurality of second electrodes which fill the second grooves and include nanowires.
9. A display device comprising the stretchable touchscreen according to claim 1; and a display panel bonded to the stretchable touchscreen through an adhesive layer.
10. The stretchable touchscreen of claim 1, further comprising a plurality of routing lines electrically connecting the first electrodes to corresponding pad electrodes, the routing lines made of same metals as the nanowires.
11. A stretchable touchscreen comprising: a stretchable substrate having a modulus of 100 MPa to 200 MPa and a strain higher than 10%; a plurality of grooves defined by removing constant first depth from the first surface of the stretchable substrate, the first depth is from 1/200 to 1/10 of a thickness of the stretchable substrate a plurality of first bridge electrodes arranged in a first direction within the plurality of grooves of the stretchable substrate, and a protecting film covering the plurality of first bridge electrodes, a plurality of first touch electrodes arranged in the first direction and disposed on the protecting film; a plurality of second touch electrodes arranged in a second direction crossing the first direction, the plurality of second touch electrodes being disposed on the protecting film; a plurality of second bridge electrodes arranged in the second direction, the plurality of second bridge electrodes crossing the first bridge electrodes, and being electrically connected to the second touch electrodes, and not overlapping with the first touch electrodes, and gaps among nanowires within each of the plurality of grooves, wherein the gaps among the nanowires are changed by elongation of the stretchable substrate; wherein each of the plurality of grooves is disposed inside the stretchable substrate and has a first predetermined depth from a first surface of the stretchable substrate, wherein each of the plurality of first bridge electrodes includes a first nanowire group filling each of the plurality of grooves, the first nanowire group has a plurality of nanowires connecting each other, each nanowires has a nanometer-scale width, wherein the second bridge electrodes, the first touch electrodes and the second touch electrodes include a second nanowire group, the second nanowire group has a plurality of nanowires connecting each other, each nanowire has a nanometer-scale width, wherein at least one of the plurality of nanowires positioned at an upper surface of each of the plurality of first bridge electrodes are coplanar with the first surface of the stretchable substrate, and wherein the first depth is from 1/200 to 1/10 of the thickness of the stretchable substrate.
12. The stretchable touchscreen according to claim 11, further comprising an organic protective film covering both of the first surface of the stretchable substrate and the plurality of first bridge electrodes.
13. The stretchable touchscreen of claim 11, further comprising a plurality of first routing lines electrically connecting the first touch electrodes to corresponding pad electrodes, and a plurality of second routing lines electrically connecting the second touch electrodes to corresponding pad electrodes, wherein the first routing lines and the second routing lines are formed of same metals as the nanowires.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:
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DETAILED DESCRIPTION OF THE INVENTION
(12) Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.
(13) The advantages, features and methods of achieving the same of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings. However, the present invention is not limited to a variety of embodiments described below and can be implemented in various forms. The embodiments of the present invention are provided only to completely disclose the present invention and fully inform a person having ordinary knowledge in the field to which the present invention pertains of the scope of the present invention. Accordingly, the present invention is defined by the scope of the claims.
(14) The shape, size, ratio, angle, number and the like shown in the drawings to illustrate the embodiments of the present invention are only for illustration and are not limited to the contents shown in the drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. In the following description, detailed descriptions of technologies or configurations related to the present invention may be omitted so as not to unnecessarily obscure the subject matter of the present invention. When terms such as “including”, “having” and “comprising” are used throughout the specification, an additional component may be present, unless “only” is used. A component described in a singular form encompasses components in a plural form unless particularly stated otherwise.
(15) It should be interpreted that the components included in the embodiment of the present invention include an error range, although there is no additional particular description.
(16) In describing a variety of embodiments of the present invention, when terms for location relation such as “on”, “above”, “under” and “next to” are used, at least one intervening element may be present between two elements unless “right” or “direct” is used.
(17) In describing a variety of embodiments of the present invention, when terms for temporal relation, such as “after”, “subsequently”, “next” and “before”, a non-continuous case may be present, unless “right” or “direct” is used.
(18) In describing a variety of embodiments of the present invention, terms such as “first” and “second” may be used to describe a variety of components, but these terms only aim to distinguish the same or similar components from one another. Accordingly, throughout the specification, a “first” component may be the same as a “second” component within the technical concept of the present invention, unless specifically mentioned otherwise.
(19) The respective features of various embodiments according to the present invention can be partially or entirely joined or combined and technically variably related Or operated, and the embodiments can be implemented independently or in combination.
(20) Hereinafter, a stretchable touchscreen, a method of manufacturing the same and a display device including the same according to the present invention will be described in detail with reference to the annexed drawings.
(21)
(22) As shown in
(23) The present invention relates to a stretchable display device shown in
Stretchable Touchscreen According to First Embodiment of the Present Invention
(24)
(25) As shown in
(26) Here, the substrate 100 may be a silicone-based film or a polyurethane-based film. However, the present invention is not limited to the aforementioned materials and any organic film material may be used without any restriction so long as it has a modulus of 100 to 200 MPa which is lower than the modulus of 4 to 10 GPa typical of plastic films such as PAC, PET, COP, PC or the like that can be used for touchscreens for flexible displays, can physically elongate in any direction and has elastic restoring force.
(27) Modulus (also referred to as “elastic modulus”) refers to a coefficient of elasticity upon elongation of a material. As modulus increases, elasticity decreases and, as modulus decreases, elasticity increases. Meanwhile, the modulus range of the substrate 100 according to the present invention is defined from 100 MPa to 200 MPa. The reason for this is that, in the case where the modulus is higher than 200 MPa, the material breaks or has difficulty of returning to an original state due to low elastic restoring force like general PET when the device is elongated to some extent. When the modulus is lower than 100 MPa, in the touch electrode array process of the stretchable touchscreen according to the present invention, the substrate loses supporting strength and the shape thereof changes.
(28) In addition, the substrate 100 according to the present invention has a strain higher than 10%. Strain indicates an increase in area of a two-dimensional object. The substrate 100 according to the present invention can be elongated to 10% above the area of the original state. In this case, elongation is possible in a two-dimension scale, that is, in a plane, in any direction.
(29) In addition, regarding the stretchable touchscreen according to the present invention, the electrodes 110 provided in the grooves 110a include nanowires made of a metal such as silver (Ag), gold (Au), copper (Cu), or molybdenum (Mo). Since the nanowires with a fine size of several nanometers are connected, the electrodes 110 can maintain their electrical connection state without breakage or fracture, thus maintaining reliability of the device, although the density of the inner structure increases or decreases upon elongation.
(30) In addition, regarding the stretchable touchscreen according to the present invention, the reason for using a material having a certain modulus for the substrate 100 is to ensure stretchability of the substrate 100. In addition, the reason for previously preparing the grooves 110a to form electrodes 110 is to clearly distinguish patterns from one another in terms of the properties of nanowires. In addition, when the grooves 110a are defined in the substrate 100 and electrodes 110 made of nanowires are provided in the grooves 110a, the part to which elongation force is mainly applied is the substrate 100, and the force does not reach the electrodes 110 in the grooves 110a. As a result, stress applied to the electrodes 110 is reduced.
(31) Meanwhile, the stretchable touchscreen according to the first embodiment of the present invention is operated in a self-capacitance manner. That is, the respective electrodes 110, which receive a signal, detect a signal change and, when the signal change is at a predetermined level or higher, it can be determined to be a touch. Accordingly, the electrodes 110 are disposed in parallel, in the same direction, for example, one direction such as an X or Y direction. In addition, the direction of the electrodes may follow the direction of one side of the substrate 100.
(32) Meanwhile, the stretchable touchscreen may include a protective film 120 covering the electrodes 110 formed in the grooves 110a and the first surface of the substrate 100. This aims at preventing exposure of the electrodes 110 where electrical signal flows as well as planarizing the surface. For these two purposes, an organic film may be used as the protective film 120. In some cases, a barrier film including an inorganic film may be further provided on the organic film.
(33) In addition, a routing line 112 having a thin line width is formed using the same metal as the nanowires of the electrodes 110 and a transparent electrode such as indium tin oxide (ITO) is patterned on the surface of the end of the routing line 112 which can be used as a pad electrode 115. In this case, the electrodes 110 and the routing line 112 can be simultaneously formed with nanowires because the nanowires have a nanometer-scale width (10.sup.−9 m=0.001 μm) and the routing line having a width of several micrometers can be applied. Meanwhile, since the pad electrode 115 is provided only on one side of the substrate 100, elongation does not have a great influence on the pad electrode 115 although elongation force is applied to the substrate 100, unlike the central region of the substrate 100, thus causing no problem such as cracking.
(34) Hereinafter, a method for manufacturing the stretchable touchscreen according to the first embodiment of the present invention will be described in detail.
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(36) As shown in
(37) The grooves 100a are formed by injection molding so as to have a predetermined depth of 1 μm to 10 μm from the first surface (i.e., the top surface) of the substrate 100 when the substrate 100 has a thickness of about 100 μm to 200 μm.
(38) Subsequently, as shown in
(39) Here, the grooves 110a previously define areas where electrodes 110 are formed, thereby solving the problem of difficulty in finely defining patterns during etching, since, like nanowires, wires are connected in the form of a chain.
(40) Subsequently, as shown in
(41) The material for the substrate 100 has excellent elastic restoring force, which has a modulus of 100 MPa to 200 MPa. Accordingly, the material has an elongation proportion of 10% to 40% from the two-dimensional initial area which is applicable to stretchable devices. In addition, although the electrodes 110 included in the grooves 110a of the substrate 100 elongate to 20% of the initial state as well, the inner structure of nanowires has a lower density, but maintains its electrical connection state and leads to a change of resistance less than 10% from the initial resistance state. This means that the stretchable display device can maintain electrical reliability even upon reception of harsh stress by elongation.
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(43) As shown in
Stretchable Touchscreen According to Second Embodiment of the Present Invention
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(45) As shown in
(46) In the plan view shown in
(47) In addition, as shown in
(48) Regarding the stretchable touchscreen according to the present invention according to the second embodiment, as shown in
(49) Here, a first interlayer insulating film 210 and a second interlayer insulating film 220 are provided between the bridge electrode 251 and the first diamond patterns 231, and contact holes 220a are provided through the first interlayer insulating film 210 and the second interlayer insulating film 220 at both ends of the bridge electrode 251. The first interlayer insulating film 210 is, for example, an insulation film including an organic film to stabilize the surface of the bridge electrode 251 provided in the lower layer, and the second interlayer insulating film 220 is a barrier film 220 including an organic film such as a nitride film to prevent moisture from permeating the organic film component. The barrier film 220 protects lower components against an etchant used to form the first diamond patterns 231 and the second diamond patterns 233 disposed thereon and the connection electrode 233a integrated with the second diamond patterns and prevents permeation of exterior air or moisture.
(50) In addition, when forming the first diamond patterns 231 and the second diamond patterns 233, and the connection electrode 233a integrated with the second diamond patterns, the contact hole 220a is also filled with the nanowire metal connected to the first diamond patterns 231, thereby causing electrical connection to the bridge electrode 251.
(51) In addition, the stretchable touchscreen according to the second embodiment of the present invention may include a protective film 260 which covers the first, second diamond patterns 231 and 233 and the connection electrode 233a as well.
(52) Meanwhile, the component represented by reference numeral “240” refers to a pad electrode and the component represented by reference numeral 230 refers to a routing line. As described above, the pad electrode 240 may be formed with a line layer including a nanowire metal in a lower part and a transparent metal such as ITO in an upper part, and the routing line 230 is defined by a groove 200a having a smaller width than that of the diamond patterns 231 and 233, and a nanowire metal which is the same layer as the bridge electrode 251 in the groove 200a.
(53) In addition, DA means a dead area and AA means an active area. The dead area DA is a region where sensing is not conducted and a pad part or lines applying a signal extend, and the active area AA means a region where actual touch is sensed by provided Rx and Tx electrodes.
(54) Meanwhile, the reference numeral ‘525’ refers to an anisotropic conductive film for bonding pad electrodes 240 to a display panel.
(55) Hereinafter, the method for manufacturing the stretchable touchscreen according to the second embodiment of the present invention will be described.
(56)
(57) As shown in
(58) As shown in
(59) Subsequently, as shown in
(60) Subsequently, both the second interlayer insulating film 220 and the first interlayer insulating film 210 are selectively etched to form contact holes 220a exposing both ends of the bridge electrodes 251.
(61) Subsequently, as shown in
(62) Subsequently, as shown in
(63) Meanwhile, in the case of the stretchable touchscreen according to the second embodiment, in terms of the function of the electrode, both the first diamond patterns 231 and the bridge electrode 251 are referred to as “first electrodes”, and both the second diamond patterns 233 and the connection electrode 233a are referred to as “second electrodes”.
(64) In addition, the first diamond patterns 231, the second diamond patterns 233 and the connection electrode 233a exposed to the upper surface of the second interlayer insulating film 220 after etching are not patterned in the form of completely regular diamonds or regular polygons and these patterns are spaced by a distance of several micrometers although the wires protrude from the edge so that, the Rx and Tx electrodes crossing each other can maintain electrical isolation.
(65) In addition, the stretchable touchscreen according to the present invention includes bridge electrodes 251 as first grooves 200a in the substrate 200 so that the same component of the bridge electrode 251 and first diamond patterns 231 are electrically connected, and the second diamond patterns 233 and the connection electrode 233a are electrically connected in a crossing direction and integrated in each direction. Accordingly, when the substrate 200 is elongated in a certain direction, electrodes of each direction receive less stress caused by elongation since nanowires are independently entangled. In addition, in terms of the structure of nanowires, although there is a part, density of which is decreased by elongation, electrical connection can be maintained and reliability of devices can be thus maintained upon touch.
Stretchable Touchscreen According to Third Embodiment of the Present Invention
(66)
(67) As shown in
(68) In this case, first grooves 300a and second grooves 300b are injection-molded on a first surface and a second surface of the substrate 300 in the same process, and the first and second grooves 300a and 300b of the respective surfaces are filled with first electrodes 310 and second electrodes 320 including nanowires.
(69) In addition, the first surface of the substrate 300 including the first electrodes 310 is covered with a first protective film 330 to protect the first surface and the second surface of the substrate 300 including the second electrode 320 is covered with a second protective film 340 to protect the second surface.
(70) Here, the first and second protective films 330 and 340 may be transparent organic films and may further include a barrier film including an inorganic film thereon.
(71) The stretchable touchscreen according to the third embodiment includes Rx and Tx electrodes which transfer different signals in separate formation areas of a single substrate 300, thereby efficiently patterning the electrodes including nanowires and operating in a mutual capacitance manner with almost no or low signal interference because additional etching of contact holes or nanowires is not needed.
(72) Meanwhile, a display device using the stretchable touchscreen according to the present invention will be described.
(73)
(74) As shown in
(75) That is, the display panel 600 includes a plurality of sub-pixels in an active area and each sub-pixel includes at least one thin film transistor and an organic light emitting diode.
(76) In order for the display panel 600 to meet requirements for flexible and stretchable display devices, a thin film transistor and an organic light emitting diode may be incorporated on a flexible substrate (not shown). In some cases, some configurations of the display panel 600 may utilize the grooves of the stretchable touchscreen and filling the grooves with electrodes including nanowires, as described above.
(77) The stretchable touch panel 100 is adhered through an adhesive layer 700 to the display panel 600 and maintains stretchability.
(78) Meanwhile, the stretchable touchscreen according to the present invention utilizes a material having a two-dimensional elongation of 10% to 40%, such as a silicone elastomer or polyurethane, which is suitable for stretchable devices and has almost no resistance change upon elongation, owing to the feature that electrodes have an irregular chain structure due to the nanowires, by filling injection-molded grooves with electrodes including nanowires, and thus maintain reliability of the operation in spite of repeated stretching.
(79) In addition, since grooves are filled with nanowires, rather than being patterned, it is possible to prevent difference in sensibility between areas upon etching, solve the disadvantages of amorphous nanowires, and maintain a desired electrode shape.
(80) The stretchable touchscreen, the method for manufacturing the same and the display device including the same according to the present invention have the following effects.
(81) After using material having a high elastic restoring force as a substrate and determining regions where touch electrodes are formed by defining grooves thereon, touch electrodes are formed by filling the grooves with nanowires. Accordingly, it is possible to maintain the elastic restoring force of the substrate and electrical connection between wires of nanowires, so that the touch electrode neither breaks nor factures despite being stretched in any direction, and reliable stretchable touchscreens can be provided due to no increase in resistance.
(82) In addition, a stretchable display device can be made by attaching such a touchscreen to a flexible display panel.
(83) The features, configurations, effects and the like described in the embodiments described above are included in at least one embodiment of the present invention and the present invention is not necessarily limited to one embodiment. Furthermore, the features, configurations, effects and the like described in the embodiments described above could be combined or modified in conjunction with other embodiments by those skilled in the art. Accordingly, contents related to such combination and modification fall within the scope of the present invention.
(84) In addition, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. For example, respective components specifically shown in the embodiments can be implemented in modified forms.