Treatment apparatus and methods of treating a substrate

Abstract

Treatment apparatus include a reservoir, a nozzle in fluid communication with the reservoir, a roller, and a pair of barriers. The nozzle is configured to dispense a liquid from the reservoir to a portion of the roller. The pair of barriers bounds the portion of the roller. Methods of treating a substrate include conveying the substrate in a conveyance direction. Methods further comprise dispensing a treatment liquid to a portion of a roller. The portion is bounded in a width direction by a pair of barriers, where the width direction is perpendicular to the conveyance direction. The width between the pair of barriers is less than half of a corresponding dimension of the substrate in the width direction. Methods further comprise transferring the treatment liquid from the roller to a portion of a first major surface of the substrate as the substrate is conveyed in the conveyance direction.

Description

TREATMENT APPARATUS AND METHODS OF TREATING A SUBSTRATECross-reference to Related Applications

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application Serial No. 63 / 569,955, filed on March 26, 2024, the content of which is relied upon and incorporated herein by reference in its entirety.FIELD

[0002] The present disclosure relates generally to treatment apparatus and methods of treating a substrate and, more particularly, to treatment apparatus and methods of treating a substrate comprising dispensing a treatment liquid to roller.BACKGROUND

[0003] Glass-based substrates are commonly used, for example, in display devices, e.g., liquid crystal displays (LCDs), electrophoretic displays (EPD), organic light-emitting diode displays (OLEDs), plasma display panels (PDPs), or the like.

[0004] It is known to etch glass-based substrates. More generally, glass-based substrates can be selectively treated by masking other portions of the substrate to allow a treatment liquid to contact the selected portion of the substrate while preventing the treatment liquid from contacting the other portions. However, the application of masks can be timeconsuming and / or costly, especially when multiple treatments are to be applied to different portions ofthe substrate. Consequently, there is aneed for new ways oftreating substrates more quickly and / or at reduced cost.SUMMARY

[0005] There are set forth herein apparatus for treating a substrate and methods of treating a substrate. Unlike conventional methods, the current disclosure provides methods (and corresponding apparatus) to selectively treat portions of the substrate (e.g., first major surface) without requiring the application of any masks to the corresponding surface (or, in some aspects, the substrate at all). This can reduce processing complexity, reduce processing time, processing cost, and / or increase a yield of the process. The treatment apparatus can dispense the treatment liquid from one or more nozzles to a portion of a roller bounded by barriers to localize the application of the treatment liquid. In aspects, the treatment liquid can then be transferred from the roller to the substrate, for example, by a meniscus on the roller - without the roller directly contacting the substrate. Also, methods enable multiple treatment liquids tobe applied simultaneously to different portions of the substrate. Additionally, the composition of a treatment liquid can be adjusted (e.g., in real-time during processing) using a mixer and either manual adjustment or a controller. In aspects, a treatment liquid applied can be an etchant that can have an etching rate of 2 pm / min or less, 1.5 pm / min or less, or 1.0 pm / min or less, which can facilitate a substantially uniform removal of material from the surface of the substrate, for example, to form a recess in the substrate. In aspects, the opposite surface can be protected from damage by spurious treatment liquid. Providing at least one conveyance roller in contact with a diluent can reduce (e.g., mitigate) an effect associated with any spurious treatment liquid (e.g., from the plurality of nozzles and / or from the roller) that contacts the conveyance rollers that could otherwise change the properties of the second major surface (not being treated at that time). Providing an etch mask on the surface not being treated can protect that surface from damage and / or spurious treatment liquid.

[0006] Some example aspects of the disclosure are described below with the understanding that any of the features of the various aspects may be used alone or in combination with one another.

[0007] Aspect 1. A treatment apparatus comprising: a reservoir; a nozzle, the nozzle in fluid communication with the reservoir; a roller, the nozzle configured to dispense a liquid from the reservoir to a portion of the roller; and a pair of barriers, the pair of barriers bounding the portion of the roller.

[0008] Aspect 2. The treatment apparatus of aspect 1, further comprising a conveyor configured to convey a substrate in a conveyance direction towards the roller, the roller configured to rotate about an axis extending in a width direction perpendicular to the conveyance direction.

[0009] Aspect 3. The treatment apparatus of aspect 2, wherein a width between the pair of barriers in the width direction is configured to be less than half of a dimension of the substrate in the width direction.

[0010] Aspect 4. The treatment apparatus of any one of aspects 2-3, wherein the conveyor is configured to convey the substrate underneath the roller.

[0011] Aspect 5. The treatment apparatus of any one of aspects 2-4, wherein the roller is confined between the pair of barriers.

[0012] Aspect 6. The treatment apparatus of aspect 5, further comprising a plurality of rollers including the roller, the plurality of rollers is aligned in a row in the width direction,each roller of the plurality of rollers is separated from an adjacent roller of the plurality of rollers by a barrier of a plurality of barriers, and the plurality of barriers includes the pair of barriers.

[0013] Aspect 7. The treatment apparatus of aspect 6. further comprising a plurality of nozzles including the nozzle, the plurality of nozzles are configured to dispense a corresponding liquid to a corresponding roller.

[0014] Aspect 8. The treatment apparatus of any one of aspects 1-4, wherein the roller comprises a plurality of portions including the portion, adjacent portions of the plurality of portions are separated by a barrier of a plurality of barriers, and the plurality of barriers includes the pair of barriers.

[0015] Aspect 9. The treatment apparatus of aspect 8, wherein a segment of the roller corresponding to a location of the barrier of the plurality of barriers is recessed relative to an outer periphery of the portion of the roller.

[0016] Aspect 10. The treatment apparatus of any one of aspects 8-9, further comprising a plurality of nozzles including the nozzle, the plurality of nozzles are configured to dispense a corresponding liquid to a corresponding portion of the roller.

[0017] Aspect 11. A treatment apparatus comprising: a plurality of reservoirs configured to hold a plurality of liquids; a plurality of mixers configured to receive fluid corresponding to the plurality of liquids from the plurality of reservoirs to produce a corresponding plurality of treatment liquids; a controller configured to control an amount of liquid flowing from at least one reservoir of the plurality of reservoirs to at least one mixer of the plurality of mixers; a plurality of nozzles configured to dispense a corresponding treatment liquid; and at least one roller configured to transfer at least one treatment liquid of the plurality of treatment liquids to a substrate.

[0018] Aspect 12. The treatment apparatus of aspect 11, further comprising a conveyor configured to convey the substrate in a conveyance direction towards roller, the at least one roller configured to rotate about an axis extending in a width direction perpendicular to the conveyance direction.

[0019] Aspect 13. The treatment apparatus of aspect 12, further comprising a plurality of barriers, wherein a portion of the at least one roller is bounded by a pair of the plurality of barriers, and the portion is configured to receive a treatment liquid dispensed by a nozzle of the plurality of nozzles.

[0020] Aspect 14. The treatment apparatus of any one of aspects 12-13, wherein the controller is manually adjustable.

[0021] Aspect 15. The treatment apparatus of aspect 13, wherein the at least one roller comprises a plurality of rollers arranged in a row in the width direction, and each roller of the plurality of rollers is separated from an adjacent roller of the plurality of rollers by a barrier of the plurality of barriers.

[0022] Aspect 16. The treatment apparatus of aspect 15, wherein the plurality of nozzles are configured to dispense the corresponding treatment liquid to a corresponding roller.

[0023] Aspect 17. The treatment apparatus of aspect 13, wherein the at least one roller comprises a roller including a plurality of portions including the portion, and adjacent portions of the plurality of portions are separated by a barrier of the plurality of barriers.

[0024] Aspect 18. The treatment apparatus of aspect 17, wherein a segment of the roller corresponding to a location of the barrier of the plurality of barriers is recessed relative to an outer periphery of the portion of the roller.

[0025] Aspect 19. The treatment apparatus of any one of aspects 17-18, wherein the plurality of nozzles are configured to dispense the corresponding treatment liquid to a corresponding portion of the roller.

[0026] Aspect 20. The treatment apparatus of any one of aspects 12-19, further comprising: at least one second roller positioned downstream in the conveyance direction from the at least one roller, the at least one second roller configured to rotate about a second axis extending in the width direction; and the at least one second roller is configured to dispense a second liquid to the at least one second roller.

[0027] Aspect 21. The treatment apparatus of any one of aspects 2-4 or 12-20 inclusive, further comprising a diluent reservoir, wherein the conveyor comprising a plurality of conveyance rollers, a conveyance roller of the plurality of conveyance rollers is aligned with the roller, the conveyance roller is at least partially positioned in the diluent reservoir and configured to transport a diluent in the diluent reservoir.

[0028] Aspect 22. The treatment apparatus of any one of aspects 12-20, wherein the roller is configured to translate in a thickness direction perpendicular to the conveyance direction and perpendicular to the width direction.

[0029] Aspect 23. The treatment apparatus of aspect 22, wherein the controller is further configured to control a translation of the roller in the thickness direction based on at least a position of the substrate.

[0030] Aspect 24. A method of treating a substrate comprising: conveying the substrate in a conveyance direction; dispensing a treatment liquid to a portion of a roller, the portion bounded in a width direction perpendicular to the conveyance direction by a pair of barriers, and a width between the pair of barriers is less than half of a dimension of the substrate in the width direction; and transferring the treatment liquid from the roller to a portion of a first major surface of the substrate as the substrate is conveyed in the conveyance direction, wherein the first major surface is opposite a second major surface.

[0031] Aspect 25. The method of aspect 24, wherein the transferring occurs by a meniscus of the treatment liquid on the roller interacting with the portion of the first major surface.

[0032] Aspect 26. The method of any one of aspects 24-25, wherein the transferring occurs as the substrate is conveyed in the conveyance direction underneath the roller.

[0033] Aspect 27. The method of any one of aspects 24-26, wherein the portion of the first major surface that the treatment liquid is transferred to is spaced from a first edge of the substrate in the width direction by a first distance and is spaced from a second edge of the substrate in the width direction by a second distance, a substrate width is defined between the first distance and the second distance, and the first distance and the second distance is equal to or greater than 10% of the substrate width.

[0034] Aspect 28. The method of any one of aspects 24-27, wherein the treatment liquid is an etchant, and the treatment liquid etches the portion of the first major surface to form a first central surface area recessed from the first major surface.

[0035] Aspect 29. The method of any one of aspects 24-28, wherein the substrate comprises a glass-based substrate or a ceramic-based substrate.

[0036] Aspect 30. The method of any one of aspects 24-29, wherein the roller is confined between the pair of barriers.

[0037] Aspect 31. The method of aspect 29, wherein a plurality of rollers including the roller is aligned in a row in the width direction, each roller of the plurality of rollers is separated from an adjacent roller of the plurality of rollers by a barrier of a plurality of barriers, and the plurality of barriers includes the pair of barriers.

[0038] Aspect 32. The method of aspect 31, further comprising:dispensing a second treatment liquid to a second roller of the plurality of rollers, the second roller is separated from the roller by at least the barrier of the plurality of barriers; and transferring the second treatment liquid from the second roller to a second portion of the first major surface of the substrate while the treatment liquid is transferred from the roller to a first portion of the substrate.

[0039] Aspect 33. The method of aspect 32, wherein a composition of the second treatment liquid is different than a composition of the treatment liquid.

[0040] Aspect 34. The method of any one of aspects 24-33, wherein a minimum distance between an outer periphery of the roller and the first major surface of the substrate is 1 millimeter or more, the minimum distance is measured in a direction perpendicular to the conveyance direction and perpendicular to a thickness direction of the substrate between the first major surface and the second major surface.

[0041] Aspect 35. The method of any one of aspects 24-30, wherein the roller comprises a plurality of portions including the portion, adjacent portions of the plurality of portions are separated by a barrier of a plurality of barriers, and the plurality of barriers includes the pair of barriers.

[0042] Aspect 36. The method of aspect 35, wherein a segment of the roller corresponding to a location of the barrier of the plurality of barriers is recessed relative to an outer periphery of the portion of the roller.

[0043] Aspect 37. The method of any one of aspects 35-36, further comprising: dispensing a second treatment liquid to a second portion of the plurality of portions of the roller, the second portion is separated from the portion by at least the barrier of the plurality of barriers; and transferring the second treatment liquid from the second portion of the roller to a second portion of the first major surface of the substrate while the treatment liquid is transferred from the portion of the roller to the portion of the substrate.

[0044] Aspect 38. The method of aspect 37, wherein a composition of the second treatment liquid is different than a composition of the treatment liquid.

[0045] Aspect 39. The method of any one of aspects 24-38, further comprising, after the transferring the treatment liquid, rinsing at least the portion of the substrate by transferring another liquid from another roller.

[0046] Aspect 40. The method of any one of aspects 24-39, wherein an entirety of the first major surface is exposed during the conveying.

[0047] Aspect 41. The method of any one of aspects 37-38, further comprising:drawing a fluid from at least one reservoir of a plurality of reservoirs; and mixing the fluid in a first mixer of a plurality of mixers to from the treatment liquid, wherein the dispensing comprises dispensing the treatment liquid from a first nozzle of a plurality of nozzles to the portion of the roller.

[0048] Aspect 42. The method of aspect 41, further comprising mixing the fluid in a second mixer of the plurality of mixers to form the second treatment liquid.

[0049] Aspect 43. The method of any one of aspects 24-42, wherein the second major surface of the substrate is masked.

[0050] Aspect 44. The method of any one of aspects 24-43, wherein the conveying comprises transporting the substrate across a plurality of conveyance rollers, a conveyance roller of the plurality of conveyance rollers is aligned with the roller, the conveyance roller is at least partially positioned in a diluent reservoir and configured to transport a diluent in the diluent reservoir.

[0051] Aspect 45. The method of aspect 44, wherein the diluent dilutes any of the treatment liquid transferred to the conveyance roller.

[0052] Aspect 46. The method of any one of aspects 24-45, wherein the roller is configured to translate from an initial position towards the first major surface as the substrate approaches and return to the initial position after the substrate passes the roller.

[0053] Throughout the disclosure, the drawings are used to emphasize certain aspects. As such, it should not be assumed that the relative size of different regions, portions, and substrates shown in the drawings are proportional to its actual relative size, unless explicitly indicated otherwise.BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The above and other features and advantages of aspects of the present disclosure are better understood when the following detailed description is read with reference to the accompanying drawings, in which:

[0055] FIG. 1 is a schematic view of an example treatment apparatus in accordance with aspects of the present disclosure;

[0056] FIG. 2 is a cross-sectional view of an example treatment apparatus taken along line 2-2 of FIG. 1 according to treatment apparatus;

[0057] FIG. 3 is an enlarged view of view 3 of FIG. 3 depicting a roller segmented by the plurality of barriers;

[0058] FIG. 4 is an another aspect of the treatment apparatus depicting a roller with segments corresponding to the plurality of barriers are recessed relative to an outer periphery of the rest of the roller;

[0059] FIG. 5 is another aspect of the treatment apparatus depicting a plurality of rollers, where each roller is positioned between and confined by an adjacent pair of barriers;

[0060] FIG. 6 schematically illustrates a mixer and a nozzle in accordance with aspects of the present disclosure;

[0061] FIG. 7 schematically illustrates plurality of reservoirs in fluid communication with a mixer that is, in turn, in fluid communication with a nozzle in accordance with aspects of the present disclosure;

[0062] FIG. 8 schematically illustrates a treatment apparatus with conveyance rollers positioned in a reservoir in accordance with aspects of the present disclosure;

[0063] FIG. 9 schematically illustrate a plurality of rollers where the rollers can translate in the thickness direction, for example, based on a position of the substrate;

[0064] FIG. 10 schematically illustrates a cross-sectional view of an example foldable apparatus comprising a tapered transition between the first portion and the central portion in accordance with aspects of the present disclosure;

[0065] FIG. 11 schematically illustrates a cross-sectional view of an example foldable apparatus with a steep transition between the first portion and the central portion in accordance with aspects of the present disclosure;

[0066] FIG. 12 is a schematic plan view of an example consumer electronic product according to aspects;

[0067] FIG. 13 is a schematic perspective view of the example consumer electronic product of FIG. 12;

[0068] FIG. 14 is a schematic perspective view of a foldable consumer electronic product.

[0069] FIG. 15 schematically illustrates a surface profile with position in mm on the horizontal axis (x-axis) and relative distance in the thickness direction shown in pm on the vertical axis (y-axis) for an example substrate treated using the treatment apparatus in accordance with methods and aspects of the present disclosure;

[0070] FIG. 16 schematically illustrates a relationship between treatment time in minutes on the horizontal axis (x-axis) and a change in a local thickness of the substrate in pm on the vertical axis (y-axis) for an example in accordance with aspects of the present disclosure;

[0071] FIG. 17- FIG. 19 schematically illustrates a surface profile with position in mm on the horizontal axis (x-axis) and relative distance in the thickness direction shown in pm on the vertical axis (y-axis) for an example substrate treated for 10 minutes, 20 minutes, and 30 minutes, respectively, using the treatment apparatus in accordance with methods and aspects of the present disclosure;

[0072] FIG. 20 schematically illustrates a surface map showing atop view of a foldable substrate made in accordance with methods and aspects of the present disclosure; and

[0073] FIG. 21- FIG. 23 schematically illustrates local thickness in pm on the vertical axis (y-axis) as a function position in mm on the horizontal axis (x-axis) for different traces of the same foldable substrate made in accordance with methods and aspects of the present disclosure.

[0074] Throughout the disclosure, the drawings are used to emphasize certain aspects. As such, it should not be assumed that the relative size of different regions, portions, and substrates shown in the drawings are proportional to its actual relative size, unless explicitly indicated otherwise.DETAILED DESCRIPTION

[0075] Aspects will now be described more fully hereinafter with reference to the accompanying drawings in which example aspects are shown. Whenever possible, the same reference numerals are used throughout the drawings to refer to the same or like parts. However, claims may encompass many different aspects of various aspects and should not be construed as limited to the aspects set forth herein.

[0076] FIGS. 1-9 illustrate schematic views of treatment apparatus 101, 801, and / or 901 in accordance with aspects of the disclosure. FIGS. 10-11 illustrate schematic cross- sectional views of foldable apparatus 1001 and / or 1101 comprising a foldable substrate 1002 in accordance with aspects of the disclosure. Unless otherwise noted, a discussion of features of aspects of one treatment apparatus, method of treating a substrate, foldable apparatus, and / or foldable substrate can apply equally to corresponding features of any aspects of the disclosure. For example, identical part numbers throughout the disclosure can indicate that, in some aspects, the identified features are identical to one another and that the discussion of the identified feature of one aspect, unless otherwise noted, can apply equally to the identified feature of any of the other aspects of the disclosure.

[0077] First, treatment apparatus 101 shown in FIG. 1 will be discussed as the components are generally applicable to the other treatment apparatus, which will be discussed in further detail later. As shown, the treatment apparatus 101 comprises a reservoir 123 in fluidconnection with a nozzle 143 one or more pipes 125 and / or 135 with an optional mixer 133 positioned therebetween. The nozzle 143 is configured to spray 151 a treatment liquid (e.g., from the reservoir 121 and / or optional mixer 133) onto a roller 161 that is configured to rotate about an axis 163 (e.g., clockwise 162 or counterclockwise 164 - extending in a width direction). The roller 161 is configured to transfer the treatment liquid to a substrate 103 being conveyed by and / or supported by a conveyance apparatus 171 (e.g., conveyance rollers 173a and 173b rotating clockwise 174a and 174b about corresponding axes 177a-177b (FIG. 8) - extending in a width direction) that can convey the substrate 103 in a conveyance direction 104. For example, as shown, the conveyance rollers 173a and 173b can the substrate 103 and be configured to convey the substrate 103 underneath the roller 161. In aspects, as indicated by dashed line 167, the nozzle 143 can be configured to spray 151 sufficient amounts of the treatment liquid to form a meniscus (dashed line 167) that can be transferred to the substrate 103 (e.g., first major surface 105) without the outer surface 165 of the roller 161 contacting the substrate 103.

[0078] As shown in FIG. 2, the nozzle 143 from FIG. 1 can be part of a plurality nozzles 141 (e.g., nozzles 143a-143c). Based on an upstream configuration (e.g., one or more reservoirs 121, one or more optional mixers 131 - discussed below) for each nozzle of the plurality nozzles 141, the composition of a corresponding treatment liquid dispensed (e.g., spray 151) by each nozzle of the plurality of nozzles 141 can be independently controlled. For example, a first nozzle 143a can dispense a first treatment liquid while the second nozzle 143b and / or the 143c can dispense another treatment liquid with a different composition. In aspects, a first set of one or more nozzles of the plurality of nozzles can dispense a common, first treatment liquid, while a second set of one or more nozzles can dispense a common, second treatment liquid. For example, the second treatment liquid can comprise a higher concentration of an etchant than the first treatment liquid (e.g., with the second set of nozzles dispensing the second treatment liquid corresponding to locations of the recess 1011 in the foldable apparatus 1001 and / or 1101 (see FIGS. 10-11) resulting from the treatment of the substrate 103.

[0079] Also, as shown in FIGS. 2-5, the plurality of nozzles 141 (e.g., nozzles 143a- 143c) can be configured to dispense a corresponding treatment liquid to a different portion of a roller 161 (FIGS. 3-4) or different rollers 503a-503d (FIG. 5). In aspects, as shown in FIG. 3-5, a spray 153a-153d of an adjacent pair of nozzles (e.g., nozzles 143a-143d) can be separated by a barrier 203a-203c or 403a-403c. For example, spray 153a from nozzle 143a can be separated from spray 153b of nozzle 143b (adjacent to nozzle 143a) by barrier 203a or 403a. In further aspects, a barrier 203a-203c or 403a-403c can be positioned between eachadjacent pair of nozzles 143a-143d to separate the corresponding sprays 153a-153d. In aspects, as shown in FIG. 3, the one or more barriers 201 (e.g., barriers 203a-203c) can be configured to mate with a shape of the roller without substantially changing the size of the roller at that location. For example, a barrier can have a portion of a circle (e.g., semi-circle) removed from its bottom with a radius of the circle removed substantially equal to or slightly greater than (e.g., from 0.1% to 10%, from 0.5% to 5%, from 1% to 3%, or any range or subrange therebetween) a radius of the roller (e.g., for a roller with a circular cross-section). In this configuration, the barrier can prevent the sprays from adjacent rollers from comingling and largely separate any meniscus of treatment liquid(s) on the outer surface 165 of the roller 161 from one another. Alternatively, in aspects, as shown in FIG. 4, the one or more barriers 401 (e.g., barriers 403a-403c) can be configured to extend beyond an outermost periphery of the outer surface 165 (e.g., a line or surface connecting the outer surface other than portions corresponding to the barriers 403a-403c). In further aspects, as shown in FIG. 4, the roller 161 can comprise recessed portions 405a-405c (e.g., relative to an outer periphery of the outer surface 165) configured to receive the one or more barriers 401 (e.g., barriers 403a-403c). For example, as shown in FIG. 4, the roller 161 comprises a recessed portion 405a configured to receive barrier 403a between a region associated with a first nozzle 143a (e.g., spray 153a) and an adjacent nozzle 143b (e.g., spray 153b). For the aspects discussed above with reference to FIGS. 2-4, the pairs of barriers can confine (e.g., define, partition, bound) a segment of the roller 161 associated with each nozzle and / or associated spray, and / or each barrier can separate segments of the roller 161 associated with adjacent pairs of nozzles and / or sprays.

[0080] Alternatively, as shown in FIG. 5, the roller can be a plurality of rollers 501 comprising rollers 503a-503d. In aspects, a barrier 403a (of the plurality of barriers 403a-403c) can be positioned between adjacent rollers 503a and 503b of the plurality of rollers 501. In further aspects, each adjacent pair of rollers 503a- 503d of the plurality of rollers 501 can be separated by a barrier of the plurality of barriers 403a-403c (e.g., positioned therebetween). In aspects, as shown, the plurality of rollers 501 (e.g., rollers 503a-503d) can be aligned in a row (e.g., single row - with a barrier of the plurality of barriers positioned between adjacent pairs of rollers) along axis 163. In aspects, the rollers 503a-503d can each have an outer surface 505a-505d that form a common outer periphery for the plurality of rollers 501. Also, in aspects as shown in FIG. 5, the barrier 403a can extend beyond an outermost periphery of the outer surface 165 (e.g., line or surface connecting the outer surface other than portions corresponding to the barriers 403a-403c).

[0081] As shown in FIGS. 3-4, a width 207a or 207b of a segment of the roller 161 can be defined between adjacent barriers (e.g., barriers 203a and 203b, or barriers 203b and 203d). In aspects, a width 207a or 207b of the segment can be less than half of a corresponding dimension (e.g., width) of the substrate 103 - such the roller 161 can have at least three segments above the substrate 103. In aspects, the width 207a or 207b can be 5 mm or more, 10 mm or more, 15 mm or more, 20 mm or more, 25 mm or more, 30 mm or more, 40 mm or more, 50 mm or more, 80 mm or less, 60 mm or less, 40 mm or less, 35 mm or less, 30 mm or less, 25 mm or less, 20 mm or less, or 15 mm or less. In aspects, the width 207a or 207b can be from 5 mm to 80 mm, from 5 mm to 60 mm, from 10 mm to 40 mm, from 10 mm to 35 mm, from 15 mm to 30 mm, from 15 mm to 25 mm, from 15 mm to 20 mm, or any range or subrange therebetween. Similarly, although not shown, with reference to FIG. 5, a width of a roller 503a- 503d of the plurality of rollers 501 can be within one or more of the ranges discussed above for the width 207a or 207b of the segment. In aspects, the roller 161 or plurality of rollers 501 can comprise a spongy material (e.g., open-celled material, polyurethane foam), a woven nap (e.g., polyamide - nylon, polyester, natural fiber - lambswool, mohair), or a substantially non- porous material (e.g., polystyrene, rubber, neoprene, polyethylene (PE)).

[0082] As shown in FIG. 3, a spray 153b of a nozzle 143b can have a swept angle 155. In aspects, the swept angle 155 can be controlled by adjusting the corresponding nozzle 143b. In aspects, as shown in FIG. 2, the distance 159 between the nozzle 143b (or the plurality of nozzles 141) and an outer surface 165 (e.g., outer periphery) of the roller 161 can be adjusted to control a spread of the corresponding spray 153b between and / or on barriers 203b and / or 203c and segment of the roller 161. In further aspects, a swept angle 155 of the spray 153b and / or the distance 159 can be adjusted such that the spray covers substantially an entire width 207a of the corresponding segment of the roller 161 without substantially impinging the barriers 203a and 203b, although other arrangements can be provided in other aspects. As shown in FIG. 2, the treatment apparatus 101 can have a support 261 that forms a structure through which rods 241 can extend, for example, to adjust the distance 159.

[0083] Additionally, aspects of the reservoir and / or mixer will now be discussed with reference to FIGS. 6-7. A mixer and plurality of reservoirs that can be connected to a single nozzle will be discussed with the understanding that other nozzles can be connected to a similar mixer and / or plurality of reservoirs. In aspects, as shown in FIG. 7, the treatment apparatus can comprise a plurality of reservoirs 121, for example, reservoirs 123a-123d, that are in fluid connection with one or more mixers 131. In further aspects, one or more of the reservoirs 123a- 123d can be configured to hold a different liquid than other reservoirs. In even further aspects,each of the reservoirs 123a-123d in fluid communication with a nozzle 143a can be different. In further aspects, as shown, a pump 127a-127 and / or a valve 129a-129d can be positioned between the corresponding reservoir 123a-123d and at least one mixer 133 of the one or more mixers 131. For example, a controller 701 can control one or more pumps 127a-127d and / or one or more valves 129a-129d to control which and / or how much of a fluid from each reservoir 123a-123d travels along a corresponding pipe 125a-125d to the mixer 133. Consequently, a composition of a treatment liquid provided to the nozzle 143a can be changed by adjusting the configuration and / or operation of the pumps 127a-127d and / or valves 129a-129d. While a composition of a treatment liquid provided to the nozzle 143a can be maintained during the treatment of a substrate, a composition of the treatment liquid can change throughout a treatment of a substrate. For example, a composition of a treatment liquid can be an etchant in a first stage of treating a substrate that can change to be a neutralizing or washing treatment liquid in a subsequent stage of treating the substrate, although multiple rollers and / or sets of nozzles can be provided as discussed with reference to FIG. 9 or a single composition of the treatment liquid provided to the nozzle 143a can be maintained.

[0084] In aspects, as shown in FIG. 6, a plurality of liquids can be provided along corresponding pipes 125a-125d to a mixer 133 as part of treatment apparatus 601. As shown in FIGS. 6-7, the mixer 133 can combine the plurality liquids provided along corresponding pipes 125a-125d to produce a treatment liquid that can be provided to the nozzle 143, for example, along pipe 135. Also, in aspects, a valve 137 can be provided between the mixer 133 and the nozzle 143a to control when and / or whether or not a treatment liquid is provided to the nozzle 143a from the mixer 133 along pipe 135. More generally, as shown in FIG. 2, the one or more mixers 131 can comprise a plurality of mixers 133a-133c. In aspects, the plurality of mixers 133a-133c can be configured to receive liquid from (e.g., in fluid communication with) the same plurality of reservoirs (e.g., with a different valve and / or pump provided between a reservoir and at least two mixers of the corresponding plurality of mixers), although additional reservoirs can be provided for other mixers in some aspects. Consequently, a plurality of mixers 131 can be configured to receive fluid corresponding to a plurality of liquids from a corresponding plurality of reservoirs 121 to produce a corresponding plurality of treatment liquids (e.g., one treatment liquid per mixer). As discussed above, a controller 701 can be configured to an amount (e.g., when and / or whether) liquid flows from at least one reservoir of the plurality of reservoirs 121 to at least one mixer of the plurality of mixers 131. In aspects, the controller and / or one or more valves 129a-129d, 137 can be manually adjustable (e.g., directly or through a manual setting on a controller - to define a composition of the treatmentliquid and / or what portions of the substrate are treated with a treatment liquid), although the controller 701 can be programmed and digitally operate the one or more valves in other aspects. In aspects, as shown in FIGS. 2 and 6-7, a mixer 133 or 133a can be in fluid communication with a single nozzle 143a (e.g., provide a treatment liquid to a single nozzle 143a), although a mixer can provide a treatment liquid to more than one nozzle in other aspects. As discussed above with reference to FIGS. 1-2, the one or more rollers (e.g., roller 161 or plurality of rollers 501) can receive treatment liquid from the plurality of nozzles 141 and transfer the treatment liquid to a substrate 103, for example, as a conveyance apparatus 171 can convey the substrate 103 in the conveyance direction 104 (e.g., towards and / or under the one or more rollers) while the one or more rollers (e.g., roller 161 or plurality of rollers 501) can rotate about an axis 163 (e.g., clockwise 162 or counterclockwise 164 - extending in a width direction). Also, a plurality of barriers 201, 401, or 501 can be provided between the plurality of nozzles 141 to define segments of the roller 161 or between the rollers of the plurality of rollers 501.

[0085] In aspects, as shown in FIGS. 1-2, the roller 161 can be configured to translate 166 in a thickness direction of the substrate 103 (e.g., a direction of the substrate thickness 109 - perpendicular to the conveyance direction 104 and axis 163), which can control a first distance 169 between the outer surface 165 (e.g., outer periphery) of the roller 161 and the first major surface 105 of the substrate 103 in the thickness direction. In further aspects, as shown in FIG. 2, the first distance 169 can be substantially equal to a thickness of a meniscus to be formed on the roller (as indicated by dashed line 167). In further aspects, the first distance 169 can be 0.5 mm or more, 0.7 mm or more, 1 mm or more, 5 mm or more, 10 mm or more, 15 mm or more, 20 mm or more, 50 mm or less, 30 mm or less, 20 mm or less, 15 mm or less, 10 mm or less, 8 mm or less, or 5 mm or less. In further aspects, the first distance 169 can be from 0.5 mm to 50 mm, from 0.7 mm to 30 mm, from 1 mm to 30 mm, from 5 mm to 20 mm, from 10 mm to 15 mm, or any range or subrange therebetween.

[0086] In aspects, as shown in FIGS. 1 and 9, the roller 161 can translate 166 based on a location of the substrate 103. In further aspects, as shown in FIG. 9, the roller 161 or 961 can be configured with the first distance 169 discussed above in the previous paragraph when the substrate 103 is underneath the (corresponding) roller 161 or 961, and the roller 161 or 971 can be at a second distance 179 or 979 (between a corresponding outer periphery of the roller and the substrate) - greater than the first distance 169 - when the substrate 103 is not underneath the roller 161 or 971. Consequently, the roller 161, 961, and / or 971 can be configured to translate 166, 966, and / or 976 in a thickness direction (e.g., substrate thickness 109) based on at least a position of the substrate 103 (e.g., in the conveyance direction 104 -going from a second distance 179 and / or 979 to the first distance 169 and to the second distance 179 and / or 979).

[0087] In aspects, as shown in FIG. 9, the treatment apparatus 901 can comprise multiple rollers 161, 961, and 971 positioned at different locations in the conveyance direction 104 It is to be understood that rollers 961 and 971 can resemble roller 161 and / or the aspects discussed above for roller 161 and the associated barriers, plurality of nozzles, optional one or more mixers, and one or more reservoirs are applicable to roller 961 and / or 971 as well. In aspects, as a second roller 961 can be positioned downstream (e.g., in the conveyance direction 104) from the roller 161. A treatment liquid dispensed to the roller 161 (and transferred to the substrate 103) can be different from another treatment liquid dispensed to the second roller 961 (and transferred to the substrate 103). For example, roller 161 can selectively dispense an etchant (e.g., based on the position of the plurality of nozzles, at locations corresponding to recess 1011 in FIGS. 10-11) while the second roller 161 can dispense (e.g., uniformly, or selectively) a neutralizing or washing treatment liquid to the substrate 103, for example, to stop the etching process. Although not shown, it is to be understood that the substrate can travel back and forth (e.g., in the conveyance direction 104 and then opposite the conveyance direction) for multiple treatment steps (e.g., with each pass or set of passes corresponding to a different treatment step). Also, although not shown, it is to be understood that the substrate can be flipped (e.g., switching the first major surface and the second major surface) to treat the second major surface after treating the first major surface.

[0088] In aspects, as shown in FIG. 8, the treatment apparatus 801 can comprise the conveyance apparatus 171, where the conveyance rollers 173a and / or 173b are in contact with a diluent 193a and / or 193b (e.g., at least partially positioned in a diluent reservoir 191a and / or 191b). In further aspects, the diluent can comprise water and / or an alkaline detergent solution. In further aspects, as shown, at least one conveyance roller 173a and / or 173b can be configured to transport the diluent 193a and / or 193b from the diluent reservoir 191a and / or 191b to the substrate 103 (e.g., second major surface 107). In further aspects, the at least one conveyance roller 173a and / or 173b in contact with the diluent 193a and / or 193b can be positioned closest to the roller 161 or plurality of rollers 501. The conveyance rollers can rotate around axis 177a and / or 177b that can be parallel to axis 163 (see FIGS. 1-2). Providing at least one conveyance roller in contact with a diluent can reduce (e.g., mitigate) an effect associated with any spurious treatment liquid (e.g., from the plurality of nozzles and / or from the roller) that contacts the conveyance rollers that could otherwise change the properties of the second major surface (not being treated at that time).

[0089] Additionally or alternatively, in aspects, as shown in FIGS. 1-2, an etch mask 183 can be disposed on the second major surface 107 of the substrate 103, although no etch mask is needed on the first major surface 105. As shown, a first surface area 185 of the etch mask 183 can contact the second major surface 107 and a second surface area 187 can contact the outer surface 175a and / or 175b of the conveyance rollers 173a and / or 173b. Providing the etch mask on the surface not being treated can protect that surface from damage and / or spurious treatment liquid.

[0090] The treatment apparatus 101, 801, and / or 901 can be used to produce a foldable substrate 1002 that can be used as part of a foldable apparatus 1001 and / or 1101 with the understanding that other products can be produced using the treatment apparatus discussed herein. As shown in FIGS. 10-11, example aspects of foldable apparatus 1001 and / or 1101 can comprise the foldable substrate 1002 in accordance with aspects of the disclosure in an unfolded (e.g., flat) configuration. The foldable substrate 1002 can be produced using methods in accordance with the present disclosure, for example, using the treatment apparatus discussed herein. In aspects, as shown in FIGS. 10-11, the foldable apparatus 1001 and / or 1101 can comprise the foldable substrate 1002. In aspects, as shown in FIG. 11, the foldable apparatus 1101 can comprise a layer (e.g., release liner 1071, PET sheet 1102) attached to the foldable substrate 1002 by an adhesive layer 1061 with the understanding that other layers (e.g., release liners, display devices) can be used in addition or instead.

[0091] Throughout the disclosure, a length of the foldable apparatus 1001 and / or 1101 is considered the dimension of the foldable apparatus 1001 and / or 1101 taken between opposed edges of the foldable apparatus 1001 and / or 1101 in a direction 1006 perpendicular to the fold axis 1016 of the foldable apparatus. In aspects, as shown in FIGS. 10-11, the foldable apparatus of any aspects of the disclosure can comprise a fold plane 1018 that includes the fold axis 1016 and a direction of a substrate thickness 1007 when the foldable apparatus is in the flat configuration (see FIG. 10). The fold plane 1018 may comprise a central axis of the foldable apparatus positioned, for example, at a second major surface 1005 of the foldable apparatus 1001 and 1101 (see FIGS. 10-11). In aspects, the foldable apparatus can be folded about the fold axis 1016. In aspects, as shown in FIGS. 10-11, the foldable apparatus 1001 and / or 1101 and / or the foldable substrate 1002 can comprise a first major surface 1003 and / or a second major surface 1005 that are substantially planar, where a central portion of the foldable apparatus can be indistinguishable from adjacent portions. As shown in FIGS. 10-11, the foldable apparatus may include a single fold axis to allow the foldable apparatus to comprise a bifold wherein, for example, the foldable apparatus may be folded in half. In further aspects,the foldable apparatus may include two or more fold axes, for example, with each fold axis including a corresponding central portion similar or identical to the central portion discussed herein.

[0092] Foldable apparatus 1001 and / or 1101 of the disclosure comprise the foldable substrate 1002. In aspects, the foldable substrate 1002 can comprise a glass-based substrate having a pencil hardness of 8H or more, for example, 9H or more. In aspects, the foldable substrate 1002 can comprise a glass-based substrate. As used herein, “glass-based” includes both glasses and glass-ceramics, wherein glass-ceramics have one or more crystalline phases and an amorphous, residual glass phase. A glass-based material (e.g., glass-based substrate) may comprise an amorphous material (e.g., glass) and optionally one or more crystalline materials (e.g., ceramic). Amorphous materials and glass-based materials may be strengthened. As used herein, the term “strengthened” may refer to a material that has been chemically strengthened, for example, through ion exchange of larger ions for smaller ions in the surface of the substrate, as discussed below. However, other strengthening methods, for example, thermal tempering, or utilizing a mismatch of the coefficient of thermal expansion between portions of the substrate to create compressive stress and central tension regions, may be utilized to form strengthened substrates. Exemplary glass-based materials, which may be free of lithia or not, comprise soda lime glass, alkali aluminosilicate glass, alkali-containing borosilicate glass, alkali-containing aluminoborosilicate glass, alkali-containing phosphosilicate glass, and alkali-containing aluminophosphosilicate glass. In one or more aspects, a glass-based material may comprise, in mole percent (mol %): SiCh from 40 mol% to 80 mol%, AI2O3 from 5 mol% to 30 mol%, B2O3 from 0 mol% to 10 mol%, ZrCh from 0 mol% to 5 mol%, P2O5 from 0 mol% to 15 mol%, TiCh from 0 mol% to 2 mol%, R2O from 0 mol% to 20 mol%, and RO from 0 mol% to 15 mol%. As used herein, R2O can refer to an alkali metal oxide, for example, Li2O, Na2O, K2O, Rb2O, and CS2O. As used herein, RO can refer to MgO, CaO, SrO, BaO, and ZnO. In aspects, a glass-based substrate may optionally further comprise from 0 mol % to 2 mol % of each of Na2SOr, NaCl, NaF, NaBr, K2SO4, KC1, KF, KBr, AS2O3, Sb2O3, SnO2, Fe2O3, MnO, Mn02, MnOs, Mn20s, M113O4, M112O7. “Glass-ceramics” include materials produced through controlled crystallization of glass. In aspects, glass-ceramics have from 1% to 99% crystallinity. Examples of suitable glass-ceramics may include Li2O-AhO3- SiO2 system (i.e., LAS-System) glass-ceramics, MgO-AhO3-SiO2 system (i.e., MAS-System) glass-ceramics, ZnO x AI2O3xnSiO2 (i.e., ZAS system), and / or glass-ceramics that include a predominant crystal phase including [3-quartz solid solution, [3-spodumene, cordierite, petalite,and / or lithium disilicate. The glass-ceramic substrates may be strengthened using the chemical strengthening processes.

[0093] The foldable substrate 1002 can comprise a glass-based substrate, and the first major surface 1003 and / or second major surface 1005 can comprise one or more compressive stress regions, for example, created by chemically strengthening. Chemically strengthening may comprise an ion exchange process, where ions in a surface layer are replaced by-or exchanged with-larger ions having the same valence or oxidation state. A compressive stress region may extend into a portion of the first portion and / or second portion for a depth called the depth of compression. As used herein, depth of compression means the depth at which the stress in the chemically-strengthened substrates and / or portions described herein changes from compressive stress to tensile stress. Depth of compression may be measured by a surface stress meter or a scattered light polariscope (SCALP, wherein values reported herein were made using SCALP-5 made by Glasstress Co., Estonia) depending on the ion exchange treatment and the thickness of the article being measured. Where the stress in the substrate and / or portion is generated by exchanging potassium ions into the substrate, a surface stress meter, for example, the FSM-6000 (Orihara Industrial Co., Ltd. (Japan)), is used to measure depth of compression. Unless specified otherwise, compressive stress (including surface CS) is measured by surface stress meter (FSM) using commercially available instruments, for example the FSM-6000, manufactured by Orihara. Surface stress measurements rely upon the accurate measurement of the stress optical coefficient (SOC), which is related to the birefringence of the glass. Unless specified otherwise, SOC is measured according to Procedure C (Glass Disc Method) described in ASTM standard C770-16. Where the stress is generated by exchanging sodium ions into the substrate, and the article being measured is thicker than 400 pm, SCALP is used to measure the depth of compression and central tension (CT). Where the stress in the substrate and / or portion is generated by exchanging both potassium and sodium ions into the substrate and / or portion, and the article being measured is thicker than 400 pm, the depth of compression is measured by SCALP. Without wishing to be bound by theory, the exchange depth of sodium may indicate the depth of compression while the exchange depth of potassium ions may indicate a change in the magnitude of the compressive stress (but not the change in stress from compressive to tensile). The refracted near-field (RNF; the RNF method is described in U.S. Patent No. 8,854,623, which is incorporated herein by reference in its entirety) method also may be used to derive a graphical representation of the stress profile.

[0094] In aspects, the first major surface 1003 of the foldable substrate 1002 can comprise a first compressive stress region extending to a first depth of compression from thefirst major surface 1003. In aspects, the second major surface 1005 of the foldable substrate 1002 can comprise a second compressive stress region extending to a second depth of compression from the second major surface. The depth of compressions correspond to a boundary of the corresponding compressive stress region where the stress profile switches from compressive to tensile (or vice versa).

[0095] As shown in FIGS. 10-11, the foldable substrate 1002 can comprise a first major surface 1003 and a second major surface 1005 opposite the first major surface 1003. In aspects, the first major surface 1003 can extend along a first plane 1004a, and / or the second major surface 1005 can extend along a second plane 1004b. As used herein, a substrate thickness 1007 of the foldable substrate 1002 is defined between the first major surface 1003 and the second major surface 1005 as an average distance therebetween. In aspects, the substrate thickness 1007 can be 10 micrometers (pm) or more, 20 pm or more, 30 pm or more, 40 pm or more, 50 pm or more, 60 pm or more, 70 pm or more, 100 pm or more, 200 pm or more, 400 pm or more, 600 pm or more, 1 mm or more, 2 mm or more, 5 mm or less, 3 mm or less, 2 mm or less, 1 mm or less, 750 pm or less, 500 pm or less, 250 pm or less, 200 pm or less, 150 pm or less, 100 pm or less, 95 pm or less, 90 pm or less, 85 pm or less, 80 pm or less, 75 pm or less, 70 pm or less, 60 pm or less, 50 pm or less, 40 pm or less, 30 pm or less, or 25 pm or less. In aspects, the substrate thickness 1007 can be from 10 pm to 5 mm, from 20 pm to 3 mm, from 30 pm to 2 mm, from 40 pm to 1 mm, from 50 pm to 750 pm, from 60 pm to 500 pm, from 70 pm to 250 pm, from 100 pm to 200 pm, from 100 pm to 150 pm, or any range or subrange therebetween. In aspects, the substrate thickness 1007 can be 100 pm or less, for example, from 10 pm to 100 pm, from 15 pm to 95 pm, from 20 pm to 80, from 25 pm to 75 pm, from 30 pm to 70 pm, from 40 pm to 60 pm, from 40 pm to 50 pm, or any range or subrange therebetween. In aspects, the substrate thickness 1007 can be from 50 pm to 100 pm, which can exhibit greater impact resistance and / or puncture resistance than even thinner foldable substrates and reasonable foldability, for example from 50 pm to 100 pm, from 50 pm to 95 pm, from 50 pm to 90 pm, from 60 pm to 80 pm, from 70 pm to 75 pm, or any range or subrange therebetween. The foldable substrate 1002 can comprise the substrate thickness 1007 in a first portion 1021 and / or in a second portion 1031.

[0096] As shown in FIGS. 10-11, the foldable substrate 1002 can comprise a first central surface area 1013 in a central portion 1081 of the foldable substrate 1002 (e.g., positioned between the first portion 1021 and the second portion 1031) that is recessed from the first major surface 1003 (e.g., first plane 1004a) and defining a recess 1011 (between the first central surface area 1013 and the first plane 1004a). In aspects, as shown, at least a portionof the first central surface area 1013 can extend along a third plane 1004c that can be parallel to the first plane 1004a. A central thickness 1009 is defined between the first central surface area 1013 and a second central surface area 1043 opposite the first central surface area 1013 as an average distance therebetween. In aspects, the central thickness 1009 can be 5 pm or more, 10 pm or more, 20 pm or more, 25 pm or more, 40 pm or more, 60 pm or more, 100 pm or more, 300 pm or more, 500 pm or more, 1 mm or less, 800 pm or less, 500 pm or less, 300 pm or less, 200 pm or less, 160 pm or less, 120 pm or less, 100 pm or less, 80 pm or less, 60 pm or less, or 50 pm or less. In aspects, the central thickness 1009 can be in a range from 5 pm to 1 mm, from 10 pm to 800 pm, from 20 pm to 500 pm, from 25 pm to 300 pm, from 40 pm to 200 pm, from 60 pm to 160 pm, from 100 pm to 120 pm, or any range or subrange therebetween. In aspects, the central thickness 1009, as a percentage of the substrate thickness 1007, can be 0.5% or more, 1% or more, 2% or more, 5% or more, 7% or more, 10% or more, 40% or less, 35% or less, 30% or less, 25% or less, 20% or less, 15% or less, 13% or less, 10% or less, or 8% or less. In aspects, the central thickness 1009, as a percentage of the substrate thickness 1007, can be in a range from 0. 1% to 40%, from 0.5% to 40%, from 1% to 35%, from 2% to 30%, from 5% to 25%, from 7% to 20%, from 10% to 15%, or any range or subrange therebetween. In aspects, the central thickness 1009 as a percentage of the substrate thickness 1007 can be 15% or less, for example, in a range from 0. 1% to 20%, from 0.5% to 15%, from 0.5% to 13%, from l% to 13%, from l% to 10%, from 2% to 10%, from 2% to 8%, from 5% to 8%, or any range or subrange therebetween. In aspects, as shown, the second central surface area 1043 can be coplanar with and / or part of the second major surface 1005, although the second central surface area can be recessed from the second major surface in other aspects.

[0097] In aspects, as shown in FIG. 10, the central portion 1081 can comprise one or more transition regions 1053 and / or 1055 with a first transition surface area 1015 and / or a second transition surface area 1017 extending between the first major surface 1003 and the first central surface area 1013. For example, a thickness of the one or more transition regions 1053 and / or 1055 can gradually increase, smoothly increase, and / or linearly increase from the central thickness 1009 to the substrate thickness 1007 over a corresponding transition width 1054 and / or 1056. Alternatively, as shown in FIG. 11, there may not be a transition region between the central thickness 1009 to the substrate thickness 1007 with the change occurring sharply over a distance less than 50 pm. A central width 1052 of the central portion 1081 includes the first central surface area 1013 and any transition region 1053 and / or 1055 that can be at least a minimum parallel plate distance that foldable substrate 1002 is configured to achieve.

[0098] In aspects, as shown in FIG. 10, a coating 1082 can be disposed over the second major surface 1005 of the foldable substrate 1002. In aspects, the coating 1082 can comprise a third major surface 1083 and a fourth major surface 1085 opposite the third major surface 1083 with a coating thickness 1087 defined as an average distance therebetween. In further aspects, as shown in FIG. 10, the coating 1082 (e.g., third major surface 1083) can contact the foldable substrate 1002 (e.g., second major surface 1005). In further aspects, the coating 1082 can comprise a coating thickness 1087 of 0. 1 pm or more, 1 pm or more, 5 pm or more, 10 pm or more, 15 pm or more, 20 pm or more, 25 pm or more, 40 pm or more, 60 pm or more, 80 pm or more, 200 pm or less, 100 pm or less, or 50 pm or less, 30 pm or less, 25 pm or less, 20 pm or less, 20 pm or less, 15 pm or less, or 10 pm or less. In aspects, the coating thickness 1087 can be from 0. 1 pm to 200 pm, from 1 pm to 100 pm, from 5 pm to 50 pm, from 10 pm to 30 pm, from 15 pm to 25 pm, from 15 pm to 20 pm, or any range or subrange therebetween. In aspects, the coating 1082 can comprise a polymeric hard coating. In further aspects, the polymeric hard coating can comprise one or more of an ethylene-acid copolymer, a polyurethane-based polymer, an acrylate resin, and a mercapto-ester resin. Example aspects of ethylene-acid copolymers include ethylene -acrylic acid copolymers, ethylene-methacrylic acid copolymers, and ethylene-acrylic-methacrylic acid terpolymers (e.g., Nucrel (DuPont)), ionomers of ethylene acid copolymers (e.g., Surlyn (DuPont)), and ethylene -acrylic acid copolymer amine dispersions (e.g., Aquacer (BYK)). Example aspects of polyurethane-based polymers include aqueous-modified polyurethane dispersions (e.g., Eleglas (Axalta)). Example aspects of acrylate resins that can be UV curable include acrylate resins (e.g., Uvekol resin (Allinex)), cyanoacrylate adhesives (e.g., Permabond UV620 (Krayden)), and UV radical acrylic resins (e.g., Ultrabond windshield repair resin). Example aspects of mercapto-ester resins include mercapto-ester triallyl isocyanurates (e.g., Norland optical adhesive NOA 61). In further aspects, the polymeric hard coating can comprise ethylene-acrylic acid copolymers and ethylene -methacrylic acid copolymers, which may be ionomerized to form ionomer resins through neutralization of the carboxylic acid residue with typically alkali-metal ions, for example, sodium and potassium, and also zinc. By providing a coating comprising a polymeric coating, the foldable apparatus can comprise low-energy fracture. In aspects, the coating can comprise a polymeric hard coating comprising an optically transparent polymeric hard-coat layer. Suitable materials for an optically transparent polymeric hard-coat layer include but are not limited to a cured acrylate resin material (e.g., poly methyl methacrylate (PMMA) and aliphatic or aromatic hexafimctional urethane acrylates), a polyimide, a polyethylene terephthalate (PET), a polycarbonate (PC), an inorganic-organic hybrid polymeric material, analiphatic or aromatic hexafunctional urethane acrylate, a siloxane -based hybrid material, and a nanocomposite material, for example, an epoxy and urethane material with nanosilicate. In aspects, an optically transparent polymeric hard-coat layer may consist essentially of one or more of these materials. As used herein, “inorganic-organic hybrid polymeric material” means a polymeric material comprising monomers with inorganic and organic components. An inorganic-organic hybrid polymer is obtained by a polymerization reaction between monomers having an inorganic group and an organic group. An inorganic-organic hybrid polymer is not a nanocomposite material comprising separate inorganic and organic constituents or phases, for example, inorganic particulates dispersed within an organic matrix.

[0099] As shown in FIGS. 10-11, the foldable apparatus 1001 and / or 1101 can comprise an adhesive layer 1061 with a first contact surface 1063 and a second contact surface 1065 opposite the first contact surface 1063. In aspects, as shown, the first contact surface 1063 of the adhesive layer 1061 can comprise a planar surface, and / or the second contact surface 1065 (FIG. 11) of the adhesive layer 1061 can comprise a planar surface. An adhesive thickness 1067 of the adhesive layer 1061 can be defined between the first contact surface 1063 and the second contact surface 1065 as the average distance therebetween excluding any portions positioned in the recess 1011. In aspects, the adhesive thickness 1067 of the adhesive layer 1061 can be 1 pm or more, 5 pm or more, 10 pm or more, 100 pm or less, 60 pm or less, 30 pm or less, or 20 pm or less (e.g., from 1 pm to 100 pm, from 5 pm to 60 pm, from 10 pm to 30 pm, from 10 pm to 20 pm). In aspects, as shown in FIG. 3, the second contact surface 1065 of the adhesive layer 1061 can face and / or contact the first major surface 1003 of the foldable substrate 1002.

[0100] In aspects, the adhesive layer 1061 can comprise one or more of a polyolefin, a polyamide, a halide-containing polymer (e.g., polyvinylchloride or a fluorine -containing polymer), an elastomer, a urethane, phenolic resin, parylene, PET, and polyether ether ketone (PEEK). Example aspects of polyolefins include PE and polypropylene (PP). Example aspects of elastomers include rubbers (e.g., polybutadiene, polyisoprene, chloroprene rubber, butyl rubber, nitrile rubber), and block copolymers (e.g., styrene-butadiene, high-impact polystyrene, poly (dichlorophosphazene). In further aspects, the adhesive layer 1061 can comprise an optically clear adhesive. In even further aspects, the optically clear adhesive can comprise one or more optically transparent polymers: an acrylic (e.g., PMMA), an epoxy, silicone, and / or a polyurethane. Examples of epoxies include bisphenol-based epoxy resins, novolac-based epoxies, cycloaliphatic-based epoxies, and glycidylamine-based epoxies. In even further aspects, the optically clear adhesive can comprise, but is not limited to acrylic adhesives, forexample, 3M 8212 adhesive, or an optically transparent liquid adhesive, for example, a LOCTITE optically transparent liquid adhesive. Exemplary aspects of optically clear adhesives comprise transparent acrylics, epoxies, silicones, and polyurethanes. For example, the optically transparent liquid adhesive could comprise LOCTITE AD 8650, LOCTITE AA 3922, LOCTITE EA E-05MR, and / or LOCTITE UK U-09LV (available from Henkel).

[0101] In aspects, as shown in FIG. 10, the adhesive layer 1061 can be positioned in the recess 1011. Alternatively, as shown in FIG. 11, the foldable apparatus 1101 can comprise a polymer-based portion 1091 positioned (at least partially in the recess 1011). As shown in FIG. 11, the polymer-based portion 1091 can be positioned between the first portion 1021 and the second portion 1031. In aspects, the polymer-based portion 1091 can be at least partially positioned in and / or fill the recess 1011, although the recess may not be totally filled, for example, to leave room for electronic devices and / or mechanical devices. A polymer thickness of the polymer-based portion 1091 is defined as an average distance between a third contact surface 1093 and a fourth contact surface 1095 opposite the third contact surface 1093. In aspects, as shown, the polymeric thickness can be substantially equal to the distance that the first central surface area 1013 is recessed from the first major surface 1003. In further aspects, as shown, the polymer-based portion 1091 can be positioned between the first central surface area 1013 and the adhesive layer 1061.

[0102] In aspects, as shown in FIG. 10, the foldable apparatus 1001 can comprise the release liner 1071 although other substrates (e.g., glass-based substrate and / or ceramic-based substrate) may be used in further aspects rather than the illustrated release liner 1071. The release liner comprises a first surface area 1073 and a second surface area 1075 opposite the first surface area 1073. In further aspects, as shown, the second surface area 1075 of the release liner 1071 can be disposed over and / or contact the adhesive layer 1061 (e.g., first contact surface 1063). A substrate comprising the release liner 1071 can comprise a paper and / or a polymer, for example polyesters (e.g., PET) and polyolefins.

[0103] In aspects, as shown in FIG. 11, alayer (e.g., PET sheet 1102) can be disposed over the first major surface 1003 of the foldable substrate 1002, and / or the layer (e.g., PET sheet 1102) can be attached to the foldable substrate 1002 by the adhesive layer 1061. As shown, the PET sheet comprises a fifth major surface 1103 and a sixth major surface 1105 opposite the fifth major surface 1103. In further aspects, the layer (e.g., sixth major surface 1105 of the PET sheet 1102) can be disposed over and / or contact the first contact surface 1063 of the adhesive layer 1061. In other aspects, the layer can comprise a polymeric material (not limited to PET) such as polyesters and polyolefins. Additionally or alternatively, the layer caninclude a display device (e.g., a liquid crystal display (LCD), an electrophoretic display (EPD), an organic light-emitting diode (OLED) display, or a plasma display panel (PDP)). The display device can be part of a portable electronic device, for example, a consumer electronic product, a smartphone, a tablet, a wearable device, or a laptop.

[0104] The foldable apparatus disclosed herein may be incorporated into another article, for example, an article with a display (or display articles) (e.g., consumer electronics, including mobile phones, tablets, computers, navigation systems, wearable devices (e.g., watches)), architectural articles, transportation articles (e.g., automotive, trains, aircraft, sea craft, etc.), appliance articles, or any article that may benefit from some transparency, scratchresistance, abrasion resistance or a combination thereof. An exemplary article incorporating any of the foldable apparatus 1001 and / or 1101 and / or foldable substrate 1002 disclosed herein is shown in FIGS. 10-11. Specifically, FIGS. 12-13 show a consumer electronic device 1200 including a housing 1202 having front 1204, back 1206, and side surfaces 1208. Although not shown, the consumer electronic device can comprise electrical components that are at least partially inside or entirely within the housing. For example, electrical components include at least a controller, a memory, and a display. As shown in FIGS. 12-13, the display 1210 can be at or adjacent to the front surface of the housing 1202. The consumer electronic device can comprise a cover substrate 1212 at or over the front surface of the housing 1202 such that it is over the display 1210. In aspects, at least one of the cover substrate 1212 or a portion of housing 1202 may include any of the foldable apparatus disclosed herein, for example, the foldable apparatus 1001 and / or 1101 and / or foldable substrate 1002.

[0105] Also, FIG. 14 shows a perspective view of a consumer electronic product 1401 that is foldable. The consumer electronic product 1401 can include the foldable apparatus 1001 and / or 1101 and / or foldable substrate 1002. The consumer electronic product 1401 can include a front surface 1403 and a side surface 1405. The consumer electronic product 1401 can include electronic components, including a display 1402 (e.g., viewed through the front surface 1403). In aspects, the consumer electronic product 1401 can be folded in a direction 1412 to form a folded configuration that brings a first end 1427 and a second end 1437 (opposite the first end 1427) closer together (than in the unfolded configuration) (e.g., folded so that the front surface 1403 and / or display 1402 faces itself, although the consumer electronic product could be folded opposite the direction 1412 so that the front surface 1403 is on the outside of the consumer electronic product in the folded configuration). The fold axis 1016 can correspond to a central portion 1481 that is located between a first portion 1421 including the first end 1427 and a second portion 1431 including the second end 1437, where a location ofthe fold axis 1016 can determine a first distance 1413 between the first end 1427 and the fold axis 1016 (e.g., in direction 1004) relative to a second distance 1415 between the second end 1437 and the fold axis 1016 (e.g., in direction 1408). A total length of the consumer electronic product can be the sum of the first distance 1413 and the second distance 1415. Also, the consumer electronic product is depicted as being in a folded or partially folded configuration with an angle A formed by front surface 1403 about the fold axis 1016. The consumer electronic product 1401 can comprise a width 1423 in direction 1424 that can be substantially equal to a width of the foldable substrate 1002.

[0106] As used herein, “foldable” includes complete folding, partial folding, bending, flexing, or multiple capabilities. As used herein, the terms “fail” and “failure” refer to breakage, destruction, delamination, or crack propagation. A foldable apparatus achieves a parallel plate distance of “X” or withstands a parallel plate distance of “X” if it resists failure when the foldable apparatus is held at parallel plate distance of “X” for 10 minutes at 25°C and 50% relative humidity. In aspects, the foldable substrate and / or the foldable apparatus can be rollable. As used herein, a foldable substrate or a foldable apparatus is “rollable” if it can achieve a threshold parallel plate distance over a length of the corresponding foldable substrate and / or foldable apparatus that is the greater of 10 mm or 10% of the length of the corresponding foldable substrate and / or foldable apparatus. As used herein, the “parallel plate distance” of a foldable apparatus and / or foldable substrate is measured by placing the foldable apparatus or foldable substrate is placed between a pair of parallel rigid stainless-steel plates as-is (without modification) and the distance between the parallel plates is reduced at a rate of 1 millimeter per second (mm / sec) until the parallel plate distance is equal to the “parallel plate distance” to be tested. Then, the parallel plates are held at the “parallel plate distance” to be tested for 10 minutes at 25°C and 50% relative humidity. As used herein, the “minimum parallel plate distance” is the smallest parallel plate distance that the foldable apparatus can withstand without failure under the conditions and configuration described above.

[0107] In aspects, the foldable apparatus 1001 and / or 1101 and / or the foldable substrate 1002 can achieve a parallel plate distance of 20 mm or less, 10 mm or less, 7 mm or less, 5 mm or less, 3 mm or less, 2 mm or less, or 1 mm or less. In aspects, the foldable apparatus 1001 and / or 1101 and / or the foldable substrate 1002 can comprise a minimum parallel plate distance of 5 mm or less, 4 mm or less, 3 mm or less, 2 mm or less, or 1 mm or less (e.g., from 0.5 mm to 5 mm, from 0.5 mm to 4 mm, from 0.5 mm to 3 mm, from 0.5 mm to 2 mm, from 1 mm to 2 mm).

[0108] Aspects of methods of treating a substrate, for example, to form the foldable substrate 1002 (e.g., in methods of making the foldable apparatus 1001 and / or 1101) illustrated in FIGS. 10-11, in accordance with aspects of the disclosure, will now be discussed. Methods of the present disclosure allow for selective treatment of portions of the substrate (e.g., first major surface) without masking the surface of the substrate being treated. This can reduce processing complexity, reduce processing time, processing cost, and / or increase a yield of the process.

[0109] Methods can start with providing a substrate 103. In aspects, the substrate 103 may be provided by purchase or otherwise obtaining a substrate or by forming the substrate. In aspects, the substrate 103 can comprise a glass-based substrate that can be provided by forming them with a variety of ribbon forming processes, for example, slot draw, down-draw, fusion down-draw, up-draw, press roll, redraw, or float. In further aspects, glass-based substrates comprising ceramic crystals can be provided by heating a glass-based substrate to crystallize one or more ceramic crystals. In aspects, as shown in FIGS. 1-2 and 8-9, the substrate 103 can comprise a planar (e.g., monolithic) substrate before being treated. In aspects, the substrate 103 can have a composition within one or more of the ranges discussed above for the glass-based substrate. In aspects, the substrate 103 can be substantially unstrengthened. As used herein, substantially unstrengthened refers to a substrate comprising either no depth of compression or a depth of compression from 0% to about 5% of the substrate thickness. Alternatively, the substrate 103 can be chemically strengthened, for example, having a depth of compression within one or more of the corresponding ranges discussed above. In aspects, as shown in FIGS. 1-2, the etch mask 183 can be disposed on the second major surface 107 while the first major surface 105 can be unmasked (e.g., the entire first major surface can be exposed), although the second major surface may not be masked in other aspects.

[0110] As shown in FIGS. 1 and 8-9, methods can comprise conveying the substrate 103 in the conveyance direction 104 towards the one or more rollers (e.g., roller 161 and / or rollers 961 and / or 971). In aspects, as discussed above with reference to FIG. 8, the substrate can be conveyed by a conveyance apparatus 171 comprising conveyance rollers 173a-173b, where one or more of the conveyance rollers (e.g., closest to the one or more rollers) can be in contact with a diluent 193a-193b (e.g., at least partially positioned in a diluent reservoir 191a- 191b containing diluent 193a-193b) that can dilute any treatment liquid transferred (e.g., incidentally, spurious) to the corresponding conveyance roller (e.g., from the one or more roller).

[0111] In aspects, as discussed above with reference to FIGS. 1-2 and 9, the one or more rollers (e.g., roller 161, plurality of rollers 501 in FIG. 5, and / or rollers 961 and / or 971) can translate 166, 966, and / or 976 based on a location of the substrate 103. For example, as the substrate 103 is conveyed towards roller 161 (e.g., within a predetermined proximity of the roller), the roller can translate 166 (e.g., in the thickness direction of the substrate thickness 109 - form a second distance 179) towards the substrate 103 to a first distance 169, which can be within one or more of the corresponding ranges discussed above. Similarly, once the substrate 103 has passed underneath the corresponding one or more rollers (e.g., passed beyond a predetermined proximity that can be the same or different than the predetermined proximity used to determine when to lower the roller), the corresponding one or more rollers can translate 166, 966, and / or 976 away from the substrate (e.g., from the first distance 169 to the second distance 179). Alternatively, the one or more rollers can be maintained at constant distance (e.g., first distance 169 in the thickness direction) throughout the method. In aspects, the first distance 169 can be within one or more of the corresponding ranges discussed above (e.g., 0.5 mm or more, 1 mm or more). In aspects, a conveyance speed that the substrate is conveyed in the conveyance direction 104 at can be 0.2 mm / s or more, 0.5 mm / s or more, 1 mm / s or more, 2 mm / s or more, 5 mm / s or more, 50 mm / s or less, 20 mm / s or less, 10 mm / s or less, 5 mm / s or less, 2 mm / s or less, or 1 mm / s or less (e.g., from 0.2 mm / s to 50 mm / s, from 0.5 mm / s to 20 mm / s, from 1 mm / s to 10 mm / s, from 1 mm / s to 5 mm / s).

[0112] In aspects, methods can form a treatment liquid to provide to the plurality of nozzles 141. In further aspects, as discussed above with reference to FIGS. 6-7. For example, methods can draw a plurality of liquids from a corresponding plurality of reservoirs 121 that are mixed in a first mixer 133 (e.g., of the plurality of mixers 131) to form a treatment liquid that is provided to one or more nozzles 143a of the plurality of nozzles 141. As discussed above, the settings for the mixer 133, pumps 127a-129 and / or valves 129a-129 and / or 137 can be controlled manually and / or by controller 701. As discussed above, the treatment liquid can be provided to one or more of the nozzles of the plurality of nozzles, although the treatment liquid can be provided to a single nozzle in other aspects. Additionally, in further aspects, a second mixer can draw liquids from reservoirs (e.g., the same or different reservoirs in fluid communication with the first mixer) to form a second treatment liquid that is provided another one or more nozzles (different from the one or more nozzles receiving the (first) treatment liquid from the first mixer) that has a different composition than the (first) treatment liquid. Alternatively, a treatment liquid (e.g., already mixed or a stock material) can be drawn from areservoir to a nozzle (e.g., without a mixer). In aspects, the treatment liquid can be an etchant, water, a detergent solution, and / or a neutralizing solution (e.g., neutralizing the etchant).

[0113] As shown in FIGS. 1-5, methods can proceed to dispensing a treatment liquid to a portion of a roller from one or more nozzles 143a-143d of the plurality of nozzles 141, for example, as spray 153a-153d and / or 151. In aspects, as discussed above, one or more of the portions of the roller 161 (FIGS. 3-4) or plurality of rollers 501 can be bounded (e.g., defined, partitioned, confined - in a width direction perpendicular to the conveyance direction 104 and the thickness direction of the substrate thickness 109) by a pair of barriers 203a-203c and / or 403a-403c of a plurality of barriers 201, 401, and / or 501. As discussed above, a width 207a, 207b of a segment (e.g., portion) of the roller 161 can be less than half of a corresponding dimension (e.g., width measured perpendicular to the conveyance direction 104 and a vertical direction (e.g., translate 166), or along the axis 163) of the roller 161 and / or within one or more of the corresponding ranges discussed above. In further aspects, as shown in FIG. 4, the roller 161 can comprise recessed portions 405a-405c (e.g., relative to an outer periphery of the outer surface 165) configured to receive the one or more barriers 401 (e.g., barriers 403a-403c) that extend. For example, as shown in FIG. 4, the roller 161 comprises a recessed portion 405a configured to receive barrier 403a between a region associated with a first nozzle 143a (e.g., spray 153a) and an adjacent nozzle 143b (e.g., spray 153b). Alternatively, as shown in FIG. 5, the roller 161 (from FIG. 2) can be a plurality of rollers 501 comprising rollers 503a-503d aligned in a row (e.g., single row - with a barrier of the plurality of barriers positioned between adjacent pairs of rollers) in the width direction (e.g., axis 163). In further aspects, abarrier 403a (of the plurality of barriers 403a-403c) can be positioned between adjacent rollers 503a and 503b of the plurality of rollers 501. Also, as shown in FIG. 5, a barrier 403a can be configured to extend beyond an outermost periphery of the outer surface 165 (e.g., a line or surface connecting the outer surface other than portions corresponding to the barriers 403a-403c).

[0114] In aspects, a first nozzle 143a can dispense (e.g., spray 153a) a first treatment liquid while a second nozzle 143b (separated from the first nozzle by a barrier 203a or 403a) can dispense (e.g., spray 153b) a second treatment liquid, where a composition of the first treatment is different than the second treatment liquid. For example, an etchant concentration can be different (e.g., greater, lower) in the first treatment liquid than the corresponding etchant concentration of the second treatment liquid, which can selectively etch a portion of the substrate corresponding to the second nozzle and the corresponding segment or the roller (or roller of the plurality of rollers). With reference to FIGS. 2 and 10-11, a second treatment liquid comprising an etchant can be dispensed by one or more nozzles in a middle portion (e.g.,one or more segments, or one or more rollers in the plurality of rollers) to the one or more segments or rollers that is then transferred to a central portion (see central portion 1081 in FIGS. 10-11) of the first major surface 105 or 1003 to form the recess 1011 in the resulting foldable substrate 1002; meanwhile, a first treatment liquid that is not an etchant solution (or no treatment liquid at all) can be dispensed by one or more nozzles in other portions to one or more segments or rollers corresponding to a first portion 1021 and / or second portion 1031 of the resulting foldable substrate 1002. In further aspects, the middle portion can correspond to a portion of the substrate that is offset from the edges (e.g., first edge and second edge - at the ends in the view shown in FIG. 2 - in the width direction of the axis 163 that is perpendicular to the conveyance direction 104) by an amount, as a percentage of a corresponding width of the substrate 103, by greater than or equal to 10%, greater than or equal to 15%, greater than or equal to 20%, greater than or equal to 25%, or greater than or equal 35% (e.g., from 10% to 45%, from 15% to 40%, from 20% to 35%, from 25% to 30%, or any range or subrange therebetween).

[0115] In aspects, as discussed above, the one or more nozzles 143a-143d of the plurality of nozzles 141 can dispense sufficient treatment liquid to form and / or maintain a meniscus (e.g., dashed line 167 in FIG. 1) on the one or more rollers (e.g., roller 161, plurality of rollers 501) such that the treatment liquid can be transferred from the meniscus to a corresponding portion of the substrate 103. For example, the one or more nozzles can be pulsed at a rate of about 0.5 seconds (s) every 10 s or more, 0.5 s every 15 s or more, 0.5 s every 18 s or more, 0.5 s ever 20 s or more, 0.5 s every 25 s or more, 0.5 s every 30 s or less, 0.5 s every 25 s or less, 0.5 s every 22 s or less, or 0.5 s every 20 s or less. Consequently, as shown in FIG. 1, methods can include transferring treatment liquid from the one or more rollers (e.g., roller 161, plurality of rollers 501 - including the meniscus formed thereon) to a portion of the first major surface 105 of the substrate 103 as the substrate 103 is conveyed in the conveyance direction 104. In further aspects, as shown in FIG. 1, the transferring of the treatment liquid occurs (e.g., primarily occurs, substantially entirely occurs) by a meniscus (e.g., dashed line 167) on the one or more rollers (e.g., roller 161, plurality of rollers 501) interacting with the corresponding portion of the first major surface 105 of the substrate 103. In further aspects, as shown in FIG. 1, the transferring of the treatment liquid occurs as the substrate 103 is underneath the one or more rollers (e.g., roller 161, plurality of rollers 501), for example, as the substrate is conveyed (e.g., continuously conveyed) in the conveyance direction 104.

[0116] In aspects, the etchant can comprise an acidic solution or an alkaline solution. In further aspects, the acidic solution can comprise one or more mineral acids. In furtheraspects, the acidic solution can comprise a fluoride ion (e.g., HF, ammonium fluoride, ammonium bifluoride, or combinations thereof). In further aspects, the alkaline solution can comprise hydroxide ions, for example, from an alkali metal hydroxide (e.g., NaOH, KOH). In aspects, an etching rate (i.e., rate of material removed from a surface of the substrate) of the etchant can be 2 pm per minute (pm / min) or less, 1.7 pm / min or less, 1.5 pm / min or less, 1.2 pm / min or less, 1.0 pm or less, 0.9 pm / min or less, 0.8 pm / min or less, 0.7 pm / min or less, 0.6 pm / min or less, 0.5 pm / min or less, 0.4 pm / min or less, 0. 1 pm / min or more, 0.2 pm / min or more, 0.3 pm / min or more, 0.4 pm / min or more, 0.5 pm / min or more, 0.7 pm / min or more, 0.9 pm / min or more, 1.1 pm / min or more, or 1.3 pm / min or more. In aspects, an etching rate can be from 0.1 pm / min to 2 pm / min, from 0.2 pm / min to 1.7 pm / min, from 0.3 pm / min to 1.5 pm / min, from 0.4 pm / min to 1.2 pm / min, from 0.5 pm / min to 1.0 pm / min, or any range or subrange therebetween. In aspects, an etching rate can be 1.0 pm / min or less, for example, from 0.1 pm / min to 1.0 pm / min, from 0.2 pm / min to 0.9 pm / min, from 0.3 pm / min to 0.8 pm / min, from 0.4 pm / min to 0.7 pm / min, or any range or subrange therebetween. Providing an etching rate of 2 pm / min or less can facilitate a substantially uniform removal of material from the surface of the substrate, for example, to form a recess in the substrate. Also, providing an etching rate of 2 pm / min can remove a relatively uniform thickness and portion of the compressive stress from the surface(s) to reduce an incidence of waviness and / or warp that can produce optical distortions that can be visible to a user of a consumer electronic product that the foldable substrate may be incorporated in.

[0117] As used herein, a pH of a solution is measured in accordance with ASTM E70-90 at 25°C. In aspects, the etchant can be an acidic solution comprising a concentration of HF of 1 molar (M) or more, 2 M or more, 3 M or more, 4 M or more, 5 M or more, 7 M or less, 5 M or less, 4 M or less, 3.5 M or less, 3 M or less, or 2.5 M or less (e.g., from 1 M to 7 M, from 2 M to 5 M, from 3 M to 4 M, or any range or subrange therebetween). Alternatively, the etchant be an acidic solution comprising a buffered HF solution and / or an aqueous acidic solution. As used herein, buffered HF means that the solution contains NH4F or a similar compound that produces F" anions in the acidic solution. In aspects, the acidic solution can comprise HF, as a wt% of the acidic solution, in an amount of 0.5 wt% or more, 0.6 wt% or more, 1.5 wt% or less, 1.25 wt% or less, 1.0 wt% or less, or 0.75 wt% wt% or less (e.g., from 0.5 wt% to 1.5 wt%, from 0.5 wt% to 1.25 wt%, from 0.5 wt% to 1.0 wt%, from 0.6 wt% to 0.75 wt%). In aspects, the acidic solution can contain NH4F, as a wt% of the acidic solution, in an amount of 0.75 wt% or more, 0.85 wt% or more, 0.9 wt% or more, 0.95 wt% or more, 1.0 wt% or more, 1.1 wt% or more, 2.5 wt% or less, 2.0 wt% or less, 1.5 wt% or less, 1.3 wt% orless, or 1.0 wt% or less (e.g., from 0.75 wt% to 2.5 wt%, from 0.8 wt% to 2.0 wt%, from 0.9 wt% to 1.5 wt%, from 1.0 wt% to 1.3 wt%).

[0118] In aspects, aperiod of time that the substrate 103 (e.g., first major surface 105) is in contact with the etchant (e.g., transferred from the one or more rollers - including a meniscus formed thereon) can be 30 seconds (s) or more, 45 s or more, 60 s or more, 90 s or more, 2 minutes (min) or more, 5 min or more, 10 min or more, 15 min or more, 1 hour or less, 45 min or less, 30 min or less, 20 min or less, 15 min or less, 10 min or less, 8 min or less, 6 min or less, 4 min or less, 3 min or less, 2 min or less, 1.5 min or less, or 1.0 min or less. In aspects, the period of time can be from 30 s to 1 hour, from 60 s to 45 min, from 2 min to 45 min, from 5 min to 30 min, from 10 min to 20 min, from 15 min to 20 min, or any range or subrange therebetween. In aspects, the period of time can be less than 5 min, for example, from 30 s to 4 min, from 45 s to 3 min, from 60 s to 2 min, from 75 s to 1.5 min, or any range or subrange therebetween. In aspects, the substrate can be passed under the one or more rollers one or more additional times during the period of time to ensure efficient etchant is provided to the substrate and / or the replenish (e.g., refresh) the etchant at predetermined portions. Alternatively, in aspects, the etchant dispensed at the beginning of the period of time can remain on the substrate for the period of time (e.g., while the substrate is held after passing under the one or more rollers, or the substrate is continuously conveyed after passing under the one or more rollers on a path corresponding to the period of time before the etchant is removed and / or neutralized and / or the substrate is rinsed). In aspects, as discussed in the next paragraph, methods can further comprise conveying the substrate through another one or more rollers (although the same one or more rollers can be used) to dispense a different one or more treatment liquids to at least a portion of the substrate, where these treatment liquids are different than the corresponding treatment liquid(s) dispensed to the corresponding portion previous (e.g., etchant).

[0119] In aspects, as shown in FIG. 9, methods can further comprise conveying the substrate 103 to (and under) one or more additional rollers 961 and / or 971 in treatment apparatus 901 In further aspects, the one or more additional rollers 961 and / or 971 can be part of a larger apparatus including a corresponding plurality of nozzles and / or plurality of barriers similar to and / or identical to that discussed above with reference to FIGS. 2-5. In further aspects, the one or more additional rollers 961 and / or 971 can dispense another treatment liquid to at least a portion of the substrate 103, although nozzles (e.g., without one or more rollers) can be used for rinsing the substrate and / or neutralizing the etchant in other aspects. For example, the treatment liquid can be transferred from the one or more additional rollers961 and / or 971 to the substrate 103 by a meniscus (similar to and / or identical to the process discussed above with reference to dashed line 167 in FIG. 1). In further aspects, the another treatment liquid can comprise water (e.g., purified, filtered, deionized, distilled), a neutralizing solution (e.g., neutralizing the etchant), a detergent solution, or combinations thereof. In even further aspects, the detergent solution can be an alkaline detergent solution having a pH of 11 or more (e.g., from 11 to 14, from 12 to 14, from 12.5 to 13.5, or any range or subrange therebetween), for example, SemiClean KG (Yokohama Oils & Fats Industry Co.). Consequently, in even further aspects, the additional treatment liquid can stop an etching of the etchant, although other combinations of treatment liquids can be used in other aspects.

[0120] In aspects, methods further can further comprise assembling a foldable apparatus from the foldable substrate produced by treating the substrate with the methods discussed herein. For example, an adhesive layer 1061, polymer-based portion 1091, release liner 1071, PET sheet 1102, display device, or other components can be disposed on and / or over the foldable substrate.EXAMPLES

[0121] Various aspects will be further clarified by the following examples. Unless otherwise indicated, the treatment apparatus comprised a plurality of rollers (see FIG. 5) with 8 rollers corresponding to a width of the substrate (160 mm) with a barrier between each adjacent pair of rollers (corresponding to a width 207a of about 20 mm). A first distance 169 (see FIGS. 1-2) of 0.5 mm was maintained between the outer periphery of the roller and the substrate. The treatment liquid was 3 M HF, which was applied to a single roller (roller 4 of 8 in the row) corresponding to a central portion being formed in the substrate (corresponding to a recess in the resulting foldable substrate). The nozzle for this roller was pulsed for 0.5 s every 18 s to maintain a meniscus on the roller. The substrate (having a substrate thickness of 100 pm) was conveyed at a rate of 1 mm / s.

[0122] The substrate was conveyed through in a first direction through roller in 5 minutes, and then the conveyance direction was reversed to go through the roller again in another 5 minutes for a 10 minute round-trip. Samples were etched with 1 round-trip (10 minutes), 2 round-trips (20 minutes), 3 round-trips (30 minute), and 4 round-trips (40 minutes). FIG. 16 presents the etched depth (corresponding to a distance that the first central surface area is recessed from the first major surface) At in pm on the vertical axis 1603 (e.g., y-axis) as a function of treatment time T in minutes (min) on the horizontal axis 1601 (e.g., x-axis). Points 1605 corresponding to 1-4 round-trips are plotted with a sigmoid curve 1607 (Gompertzfunction) fit to points 1605. As shown, the etched depth increases as the treatment time increases.

[0123] FIG. 15 shows a surface profile 1505 with position in mm on the horizontal axis 1501 (e.g., x-axis) and relative distance in the thickness direction shown in pm on the vertical axis 1503 (e.g., y-axis) for the sample measured after 4 round-trips (40 minutes). As shown, an etched depth of the first central surface area is about 47 pm (47. 1 pm). A width of the central portion is about 18 mm including transition regions having a width of about 2 mm. As shown, internal angles of about 178° (e.g., 177.74° and 178.18°) of the transition regions are measured for linear fits to portions near the top of the transition region relative to the reference plane (nominally corresponding to an idealized, planar first major surface).

[0124] FIGS. 17-19 show surface profiles with position X in mm on the horizontal axis 1701, 1801, 1901 (e.g., x-axis) and relative distance t in the thickness direction shown in pm on the vertical axis 1703, 1803, 1903 (e.g., y-axis) for an example substrate treated for 10 minutes (1 round-trip, FIG. 17), 20 minutes (2 round-trips, FIG. 18), and 30 minutes (3 roundtrips, FIG. 19), respectively. As shown, the etched depth increases going from FIG. 17 to FIG. 19 (from less than 5 mm after 10 minutes to about 25 mm after 20 minutes to about 41 mm after 30 minutes - consistent with trend see in FIG. 16). Also, the internal angle of the transition regions decreases as the treatment time increases (e.g., from about 179.9° after 10 minutes to about 169.6° after 20 minutes to about 179.0° after 30 minutes) as the etched depth increases. For the specific conditions tested, the surface profile after 10 minutes looks rough, but this smooths out for longer times. Also, it was noted that excess etchant dripped from the rollers, indicating that the nozzle pulse schedule was perhaps to frequent. It is expected that a longer pulse schedule could eliminate this and perhaps produce a flatter etched surface (e.g., first central surface area).

[0125] FIG. 20 schematically illustrates a surface map showing a top view of a foldable substrate formed after 30 minutes (3 round-trips). Contours are drawn in to convey the shape of the surface. The major surfaces have peripheral portions 2007 with the substrate thickness (100 pm) and portions 2005 closer to the central portion with slightly decreased thickness (about 97 pm). Again, it is believed that excess treatment liquid and / or splashing in this test configuration resulted in this slight decrease, which it is believed can be eliminated with minor adjustment of the nozzle and corresponding pulse schedule. On the scale of the entire test substrate, the transition region 2003 is relatively narrow, where the thickness goes from about 97 pm to less than 75 pm (other than edge portions 2002). Edge portions 2002 have a thickness of about 78 pm, and it is believed that this may have been the result of an alignmentof the substrate being slightly off (which could be fixed). The bulk of the central portion 2001 had a thickness of from 62 pm to less than 70 pm (see also the surface profile shown in FIG. 19).

[0126] FIGS. 21-23 schematically illustrates traces 2105, 2205, 2305 of the local thickness in pm on the vertical axis 2103, 2203, 2303 (e.g., y-axis) as a function position in mm on the horizontal axis 2101, 2201, 2301 (e.g., x-axis) for different traces equally spaced along the sample substrate treated for 30 minutes (3 round-trips). These are the raw (uncorrected surface profiles) measured where the left edge was set at 100 pm, which is why the local thickness does not necessarily align between these figures and those discussed above. As shown, the traces 2105, 2205, and 2305 generally have the same shape. As discussed above, the shoulders leading up to the transition region can likely be eliminated with minor process adjustment. Also, the deeper right side of recess 2107, 2207, and 2307 in the thickness traces (especially trace 2305) can likely be reduced by adjusting the nozzle pulse schedule and alignment of the substrate.

[0127] The above observations can be combined to provide apparatus for treating a substrate and methods of treating a substrate. Unlike conventional methods, the current disclosure provides methods (and corresponding apparatus) to selectively treat portions of the substrate (e.g., first major surface) without requiring the application of any masks to the corresponding surface (or, in some aspects, the substrate at all). This can reduce processing complexity, reduce processing time, processing cost, and / or increase a yield of the process. The treatment apparatus can dispense the treatment liquid from one or more nozzles to a portion of a roller bounded by barriers to localize the application of the treatment liquid. In aspects, the treatment liquid can then be transferred from the roller to the substrate, for example, by a meniscus on the roller - without the roller directly contacting the substrate. Also, methods enable multiple treatment liquids to be applied simultaneously to different portions of the substrate. Additionally, the composition of a treatment liquid can be adjusted (e.g., in real-time during processing) using a mixer and either manual adjustment or a controller. In aspects, a treatment liquid applied can be an etchant that can have an etching rate of 2 pm / min or less, 1.5 pm / min or less, or 1.0 pm / min or less, which can facilitate a substantially uniform removal of material from the surface of the substrate, for example, to form a recess in the substrate. In aspects, the opposite surface can be protected from damage by spurious treatment liquid. Providing at least one conveyance roller in contact with a diluent can reduce (e.g., mitigate) an effect associated with any spurious treatment liquid that contacts the conveyance rollers that could otherwise change the properties of the second major surface (not being treated at thattime) . Providing an etch mask on the surface not being treated can protect that surface from damage and / or spurious treatment liquid.

[0128] Directional terms as used herein — for example, up, down, right, left, front, back, top, bottom — are made only with reference to the figures as drawn and are not intended to imply absolute orientation. It is also to be understood that, as used herein the terms “the,” “a,” or “an,” mean “at least one,” and should not be limited to “only one” unless explicitly indicated to the contrary. For example, reference to “a component” comprises aspects having two or more such components unless the context clearly indicates otherwise. Likewise, a “plurality” denotes “more than one.”

[0129] The terms “substantial,” “substantially,” and variations thereof as used herein are intended to note that a described feature is equal or approximately equal to a value or description. For example, a “substantially planar” surface denotes a surface that is planar or approximately planar. Also, “substantially similar” denotes that two values are equal or approximately equal, for example within 10% (±10%) of each other, within 5% (±5%) of each other, or within 2% (±2%) of each other.

[0130] Unless expressly stated, it is in no way intended that any method herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed or it is not otherwise specifically stated that the steps are limited to a specific order, no particular order is intended to be inferred. While various features, elements, or steps of particular aspects may be disclosed using the transitional phrase “comprising,” it is to be understood that alternative aspects, including those described using the transitional phrases “consisting of’ or “consisting essentially of,” are implied. For example, implied alternative aspects to an apparatus comprising A±B±C includes aspects where an apparatus consists of A±B±C and aspects where an apparatus consists essentially of A±B±C. The terms “comprising” and “including” shall be construed as synonymous and open-ended unless otherwise indicated.

[0131] It will be appreciated that the various disclosed aspects may involve features, elements, or steps that are described in connection with that aspect. It will also be appreciated that a feature, element, or step, although described in relation to one aspect, may be interchanged or combined with alternate aspects in various non-illustrated combinations or permutations. The above aspects, and the features of those aspects, are exemplary and can be provided alone or in any combination with any one or more features of other aspects provided herein without departing from the scope of the disclosure. It will be apparent to those skilled in the art that various modifications and variations can be made to the present disclosurewithout departing from the spirit and scope of the disclosure. Thus, it is intended that the present disclosure cover the modifications and variations of the aspects herein provided they come within the scope of the appended claims and their equivalents.

Claims

What is claimed is:1 . A treatment apparatus comprising: a reservoir; a nozzle, the nozzle in fluid communication with the reservoir; a roller, the nozzle configured to dispense a liquid from the reservoir to a portion of the roller; and a pair of barriers, the pair of barriers bounding the portion of the roller.

2. The treatment apparatus of claim 1 , further comprising a conveyor configured to convey a substrate in a conveyance direction towards the roller, the roller configured to rotate about an axis extending in a width direction perpendicular to the conveyance direction.

3. The treatment apparatus of claim 2, wherein a width between the pair of barriers in the width direction is configured to be less than half of a dimension of the substrate in the width direction.

4. The treatment apparatus of any one of claims 2-3, wherein the conveyor is configured to convey the substrate underneath the roller.

5. The treatment apparatus of any one of claims 2-4, wherein the roller is confined between the pair of barriers.

6. The treatment apparatus of claim 5, further comprising a plurality of rollers including the roller, the plurality of rollers is aligned in a row in the width direction, each roller of the plurality of rollers is separated from an adjacent roller of the plurality of rollers by a barrier of a plurality of barriers, and the plurality of barriers includes the pair of barriers.

7. The treatment apparatus of claim 6, further comprising a plurality of nozzles including the nozzle, the plurality of nozzles are configured to dispense a corresponding liquid to a corresponding roller.

8. The treatment apparatus of any one of claims 1-4, wherein the roller comprises a plurality of portions including the portion, adjacent portions of the plurality of portions areseparated by a barrier of a plurality of barriers, and the plurality of barriers includes the pair of barriers.

9. The treatment apparatus of claim 8, wherein a segment of the roller corresponding to a location of the barrier of the plurality of barriers is recessed relative to an outer periphery of the portion of the roller.

10. The treatment apparatus of any one of claims 8-9, further comprising a plurality of nozzles including the nozzle, the plurality of nozzles are configured to dispense a corresponding liquid to a corresponding portion of the roller.

11. A method of treating a substrate comprising: conveying the substrate in a conveyance direction, the substrate comprises a glassbased material or a ceramic-based material; dispensing a treatment liquid to a portion of a roller, the portion bounded in a width direction perpendicular to the conveyance direction by a pair of barriers separated, and a width between the pair of barriers is less than half of a dimension of the substrate in the width direction; and transferring the treatment liquid from the roller to a portion of a first major surface of the substrate as the substrate is conveyed in the conveyance direction, wherein the first major surface is opposite a second major surface.

12. The method of claim 11, wherein the transferring occurs by a meniscus of the treatment liquid on the roller interacting with the portion of the first major surface.

13. The method of any one of claims 11-12, wherein the portion of the first major surface that the treatment liquid is transferred to is spaced from a first edge of the substrate in the width direction by a first distance and is spaced from a second edge of the substrate in the width direction by a second distance, a substrate width is defined between the first distance and the second distance, and the first distance and the second distance is equal to or greater than 10% of the substrate width.

14. The method of any one of claims 11-13, wherein the treatment liquid is an etchant, and the treatment liquid etches the portion of the first major surface to form a first central surface area recessed from the first major surface.

15. The method of any one of claims 11-14, wherein the roller is confined between the pair of barriers, wherein a plurality of rollers including the roller is aligned in a row in the width direction, each roller of the plurality of rollers is separated from an adjacent roller of the plurality of rollers by a barrier of a plurality of barriers, and the plurality of barriers includes the pair of barriers.

16. The method of any one of claims 11-15, wherein a minimum distance between an outer periphery of the roller and the first major surface of the substrate is 1 millimeter or more, the minimum distance is measured in a direction perpendicular to the conveyance direction and perpendicular to a thickness direction of the substrate between the first major surface and the second major surface.

17. The method of any one of claims 11-16, wherein the roller comprises a plurality of portions including the portion, adjacent portions of the plurality of portions are separated by a barrier of a plurality of barriers, and the plurality of barriers includes the pair of barriers.

18. The method of any one of claims 11-17, further comprising: dispensing a second treatment liquid to a second portion of the plurality of portions of the roller, the second portion is separated from the portion by at least the barrier of the plurality of barriers; and transferring the second treatment liquid from the second portion of the roller to a second portion of the first major surface of the substrate while the treatment liquid is transferred from the portion of the roller to the portion of the substrate.

19. The method of any one of claims 11-18, further comprising, after the transferring the treatment liquid, rinsing at least the portion of the substrate by transferring another liquid from another roller.

20. The method of any one of claims 11-19, wherein the conveying comprises transporting the substrate across a plurality of conveyance rollers, a conveyance roller of the plurality ofconveyance rollers is aligned with the roller, the conveyance roller is at least partially positioned in a diluent reservoir and configured to transport a diluent in the diluent reservoir, and wherein the diluent dilutes any of the treatment liquid transferred to the conveyance roller.

21. The method of any one of claims 11-20, wherein the roller is configured to translate from an initial position towards the first major surface as the substrate approaches and return to the initial position after the substrate passes the roller.

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