Detailed Description
Reference will now be made in detail to the various embodiments, one or more examples of which are illustrated in each figure. The examples are provided by way of explanation and are not meant as limitations. For example, features illustrated or described as part of one embodiment can be used on or in conjunction with any other embodiment to yield yet a further embodiment. It is intended that the present disclosure include such modifications and variations.
In the following description of the drawings, the same reference numerals indicate the same or similar components. In general, only the differences between the individual embodiments will be described. Descriptions of parts or aspects in one embodiment can also apply to corresponding parts or aspects in another embodiment, unless explicitly stated otherwise.
Before describing various embodiments of the present disclosure in more detail, certain aspects will be explained with respect to certain terms and expressions used herein.
In the present disclosure, a "hard coating system" is understood to be a multilayer stack in which at least the topmost layer comprises a hard coating. In particular, a "hard coating system" can be understood as a stack of layers comprising an inorganic hard coating top layer. More particularly, the hard coating can be characterized as having a pencil hardness of at least 2H. In this regard, it will be understood that the resistance to coating, i.e. the hardness of the coated layer, can be determined as the grade of the hardest pencil that does not permanently leave a mark when firmly pressed against the coated layer at an angle of 45 degrees. Typically, the pencil is pressed against the surface to be tested with a force of 7.5N. The pencil hardness test is also known as the "Wolff-Wilborn test".
In the present disclosure, a "layer stack" is understood to be a multilayer stack having at least two layers of different material compositions. In particular, the multilayer stack described herein can be transparent. The term "transparent" as used herein can in particular include structures having the ability to transmit light in a relatively low scattering manner, so that for example light transmitted therethrough can be seen substantially in a clear manner.
In the present disclosure, a "flexible substrate" may be characterized as a substrate that is bendable. For example, the flexible substrate may be a foil. In particular, it will be understood that the flexible substrates described herein may be processed in a continuous roll-to-roll process as described herein, such as in a roll-to-roll processing system as described herein. In particular, the flexible substrates described herein are suitable for use in the manufacture of coatings or electronic devices on flexible substrates. In particular, the flexible substrate described herein can be transparent, e.g., the flexible substrate can be made of a transparent polymeric material. More particularly, the flexible substrate described herein may comprise materials like the following: polyethylene terephthalate (PET), Polycarbonate (PC), Polyethylene (PE), Polyimide (PI), Polyurethane (PU), polymethyl methacrylate (poly (methacrylic acid) ester), cellulose triacetate (triacetyl cellulose), cellulose Triacetate (TAC), cyclic olefin polymer (cyclo olefin polymer), polyethylene terephthalate (poly (ethylene naphthalate)), one or more metals, paper, combinations thereof, and coated substrates such as: hard-coated PET (HC-PET) or TAC (HC-TAC), and the like.
In the present disclosure, an "adhesion promoting layer" is understood to be a layer disposed between two structures, such as a substrate and a layer therebetween or a layer between two layers, and configured to promote adhesion between the two structures. For example, the adhesion promoting layer APL can be configured to be covalently bonded to at least one of the two structures between which the adhesion promoting layer is disposed. Thus, the adhesion promoting layer APL can be configured to be covalently bonded to the flexible substrate described herein and/or to a subsequent layer deposited on the adhesion promoting layer APL. Further, the mechanical properties of the adhesion promoting layer can be adapted to the mechanical properties of the flexible substrates described herein. For example, the flexibility, e.g. the elastic modulus, of the adhesion promoting layer APL can be adapted to the mechanical properties of the flexible substrate. Accordingly, since the adhesion promoting layer APL may follow the deformation of the flexible substrate, the adhesion of the adhesion promoting layer APL to the substrate may be improved.
In the present disclosure, "hard-coated top layer" is understood to be the topmost layer of a multilayer stack. In particular, the hard coat top layer can be characterized as having a pencil hardness of at least 2H.
FIG. 1 shows a schematic view of a hard coating system according to embodiments described herein. According to various embodiments, which can be combined with any other embodiment described herein, the hard coating system is suitable for use in a touch screen panel. In particular, the hard coating system includes a flexible substrate 101 and a layer stack 110 disposed on the flexible substrate 101. For example, the flexible substrate 101 may include a polymer material selected from the group consisting of polycarbonate (polycarbonate), polyethylene terephthalate (polyethylene terephthalate), polymethyl methacrylate (poly (methacrylic acid methyl ester)), cellulose triacetate (triacetyl cellulose), cyclo olefin polymer (cyclo olefin polymer), and poly (ethylene terephthalate). As exemplarily shown in fig. 1, the layer stack 110 comprises an adhesion promoting layer 111 and an inorganic hard coat top layer 113, the adhesion promoting layer 111 being disposed on the flexible substrate 101. The adhesion promoting layer 111 is configured to be covalently bonded to a surface of the flexible substrate. Further, the mechanical properties of the adhesion promoting layer 111 at the interface 102 with the flexible substrate 101 are adapted to the mechanical properties of the flexible substrate 101. For example, the flexibility, such as the elastic modulus, of the adhesion promoting layer APL may be adapted to the mechanical properties of the flexible substrate.
Accordingly, various embodiments described herein provide improved hard coating systems. In particular, the hard coating systems described herein have improved structural stability and integrity (integration) compared to conventional hard coating systems. Thus, by employing various embodiments of the hard coating system as described herein in an optoelectronic device, such as a display device or touch panel, structural stability and scratch resistance may be improved such that improved product durability of the optoelectronic device may be achieved.
With exemplary reference to FIG. 2, according to various embodiments, which can be combined with any of the other embodiments described herein, the adhesion promoting layer 111 can have a T of 100nm ≦ TAPLThickness T less than or equal to 800nmAPL。
For example, the thickness T of the adhesion promoting layer 111APLMay be selected from a range having a lower limit and an upper limit. The lower limit is 100nm, in particular 200nm, more in particular 300nm, and the upper limit is 600nm, in particular 700nm, more in particular 800 nm. Thus, by providing a film having a thickness T as described hereinAPLThe hardness layer system of the adhesion promoting layer of (2), the stability of the entire hard coating system can be improved.
Further, referring exemplarily to fig. 2, according to various embodiments, which can be combined with any other embodiments described herein, the inorganic hardcoat top layer 113 has a thickness THTLCan be 100nm or less THTLLess than or equal to 1 mu m. For example, the thickness T of the inorganic hardcoat top layerHTLMay be selected from a range having a lower limit and an upper limit. The lower limit is 100nm, in particular 200nm, more in particular 300nm, and the upper limit is 600nm, in particular 800nm, more in particular 1 μm. Thus, by providing a film having a thickness T as described hereinHTLThe hard coating system of the inorganic hard coating top layerThe overall hard coating system stability can be improved, in particular the scratch resistance can be improved.
According to various embodiments, which can be combined with any of the other embodiments described herein, the adhesion promoting layer 111 comprises silicon oxycarbide SiOxCy. In particular, the adhesion promoting layer 111 may be formed of silicon oxycarbide SiOxCyAnd (4) forming. Thus, by employing an adhesion promoting layer having the material composition described herein, the adhesion promoting layer is configured to covalently bond to the surface of the flexible substrate described herein, which facilitates improved structural stability of the hardcoat system.
According to various embodiments, which can be combined with any of the other embodiments described herein, the inorganic hard coat top layer 113 comprises silicon oxide SiOx. In particular, the inorganic hard coat top layer 113 can be made of silicon oxide SiOxAnd (4) forming. Alternatively, the inorganic hard coating top layer 113 may comprise silicon carbide SiC, in particular the inorganic hard coating top layer 113 can consist of silicon carbide SiC.
According to various embodiments that can be combined with any of the other embodiments described herein, the inorganic hard coat top layer has a pencil hardness of from 2H to 9H. For example, the pencil hardness of the inorganic hard coat layer can be 2H, 3H, 4H, 5H, 6H, 7H, 8H, or 9H. The pencil hardness of the inorganic hard coat top layer can be measured using the pencil hardness test, also known as the Wolff-Wilborn test. In particular, the hardness of the hard coat top layer can be determined as the grade of the hardest pencil that does not permanently leave a mark on the hard coat top layer when firmly pressed against the hard coat top layer at an angle of 45 degrees. Typically, the pencil is pressed against the surface to be tested, e.g. the surface of the inorganic hard-coated top layer, with a force of 7.5N.
Referring to fig. 4 and 5 for example, according to various embodiments that may be combined with any of the other embodiments described herein, the layer stack 110 may further include an anti-reflective layer stack 120 disposed between the adhesion-promoting layer 111 and the inorganic hard-coated top layer 113. For example, as exemplarily shown in fig. 4, the anti-reflective layer stack 120 may include SiO disposed on the adhesion-promoting layer 111x First layer 121, NbO disposed on the first layer 121x Second layer 122 and SiO disposed on second layer 122xAnd a third layer 123. Further, as exemplarily shown in fig. 5, the anti-reflective layer stack 120 may include a fourth layer 124 of ITO (indium tin oxide) disposed on the third layer 123.
For example, the first layer 121 can have a T ≦ 5nm1Thickness T less than or equal to 10nm1. For example, the thickness T of the first layer 1211Can be selected from a range having a lower limit and an upper limit. The lower limit is 5nm, in particular 6nm, more in particular 7nm, and the upper limit is 8nm, in particular 9nm, more in particular 10 nm.
The second layer 122 may have a T of 5nm ≦ T2Thickness T less than or equal to 10nm2. For example, the thickness T of the second layer 1222Can be selected from a range having a lower limit and an upper limit. The lower limit is 5nm, in particular 6nm, more in particular 7nm, and the upper limit is 8nm, in particular 9nm, more in particular 10 nm.
The third layer 123 can have a T of 40nm ≦ T3Thickness T less than or equal to 80nm3. For example, the thickness T of the third layer 1233Can be selected from a range having a lower limit and an upper limit. The lower limit is 40nm, in particular 45nm, more in particular 50nm, and the upper limit is 60nm, in particular 70nm, more in particular 80 nm.
The fourth layer 124 can have a T of 20nm ≦ T4Thickness T less than or equal to 60nm4. For example, the thickness T of the fourth layer 1244Can be selected from a range having a lower limit and an upper limit. The lower limit is 20nm, particularly 25nm, more particularly 30nm, and the upper limit is 40nm, particularly 50nm, more particularly 60 nm.
Providing a hard coat system with an anti-reflective layer stack 120 as described herein can be advantageous for enhancing the optical performance of the hard coat system compared to conventional layer structures, particularly for use in optoelectronic devices such as OLED displays. For example, the layer stacks described herein may be advantageous for achieving a hard coating system with anti-reflective properties.
Referring to fig. 6 exemplarily, according to some embodiments, which may be combined with other embodiments described herein, an additional adhesion-promoting layer 112 may be disposed between the anti-reflective layer stack 120 and the inorganic hard coat top layer 113. For example, the thickness of the other adhesion-promoting layer 112 can be selected from a range having a lower limit and an upper limit. The lower limit is 100nm, in particular 200nm, more in particular 300nm, and the upper limit is 600nm, in particular 700nm, more in particular 800 nm. Thus, by providing a hard coat system with an additional adhesion promoting layer having a thickness as described herein, overall hard coat system stability may be improved.
Further, according to some embodiments, which can be combined with other embodiments described herein, the other adhesion promoting layer 112 can be configured to be covalently bonded to the topmost layer of the anti-reflective layer stack 120, such as to the third layer 123 or the fourth layer 124. Further, the mechanical properties of the other adhesion promoting layer 112 may be adapted to the mechanical properties of the topmost layer of the anti-reflective layer stack 120, e.g. the mechanical properties of the third layer 123 or the fourth layer 124. For example, the flexibility, e.g., elastic modulus, of other adhesion promoting layers can be adapted to the mechanical properties of the topmost layer of the anti-reflective layer stack 120. Thus, the structural stability and integrity of the hard coating systems described herein may be improved more than conventional hard coating systems.
According to examples that may be combined with other embodiments described herein, a hard coating system 100 suitable for use in a touch screen panel includes a flexible substrate 101. The flexible substrate 101 is selected from the group consisting of polycarbonate (polycarbonate), polyethylene terephthalate (polyethylene terephthalate), polymethyl methacrylate (poly (methacrylic acid methyl ester)), cellulose triacetate (triacetyl cellulose), cyclic olefin polymer (cyclo olefin polymer), and poly (ethylene terephthalate). Further, the hard coating system 100 comprises a layer stack 110 disposed on the flexible substrate 101, wherein the layer stack 110 comprises an adhesion promoting layer 111 and an inorganic hard coating top layer 113, the adhesion promoting layer 111 being disposed on the flexible substrate 101. In particular, the adhesion promoting layer 111 is configured to be covalently bonded to the surface of the flexible substrate, wherein the hardness of the adhesion promoting layer 111 can be configured to gradually increase from the flexible substrate to the inorganic hardcoat top layer 113. The inorganic hard coat layer 113 can have a pencil hardness of from 2H to 9H. Generally, the adhesion-promoting layer 111 and the inorganic hard coat top layer 113 are deposited by a roll-to-roll PECVD process using one and the same precursor.
Thus, in view of the embodiments of the hard coating system described herein, it will be appreciated that the hard coating system is well suited for being manufactured in a continuous roll-to-roll process, particularly in a continuous vacuum deposition roll-to-roll process.
By way of example, a processing system 300 for manufacturing a hard coating system according to embodiments described herein is shown in FIG. 7. In particular, fig. 7 illustrates a roll-to-roll processing system configured to perform a method for manufacturing a hard coating system in a continuous roll-to-roll process according to embodiments described herein.
As illustrated in fig. 7, the processing system 300 can include at least three chamber sections, such as a first chamber section 302A, a second chamber section 302B, and a third chamber section 302C. In the third chamber section 302C, one or more deposition sources 630 and optional etch stations 430 can be provided as processing tools. A flexible substrate 101, such as the flexible substrate described herein, is disposed on a first roller 764, such as having a shaft. The flexible substrate is unwound from the first roller 764 as shown by the direction of substrate movement shown by arrow 108. A partition wall 701 is provided to separate the first chamber section 302A and the second chamber section 302B. The partition wall 701 can be further provided with a gap gate (gap gates) 740 to allow the flexible substrate 101 to pass therethrough. The vacuum flange 312 disposed between the second chamber section 302B and the third chamber section 302C can be provided with apertures to receive at least some of the processing tools.
The flexible substrate 101 moves through a deposition area disposed at the coating drum 710 and a position corresponding to the deposition source 630. During operation, the coating drum 710 rotates about an axis such that the flexible substrate 101 moves in the direction of arrow 108. According to some embodiments, the flexible substrate 101 is directed from the first roller 764 to the coating drum 710 via one, two or more rollers and from the coating drum 710 to the second roller 764', e.g. having an axis of rotation. The flexible substrate 101 is wound on the second roller 764' after the coating drum process.
According to some embodiments, the deposition source 630 can be configured to deposit the layers of the hard coating systems described herein. As an example, at least one deposition source can be adapted to deposit the adhesion promoting layer 111 and at least one deposition source can be adapted to deposit the inorganic hard coat top layer 113. Further, respective deposition sources may be provided, which are adapted for depositing the first layer 121, the second layer 122, the third layer 123, the fourth layer 124 and the further adhesion promoting layer 112.
In some embodiments, the first chamber portion 302A is separated into an interleaf chamber portion unit 302A1 and a substrate chamber portion unit 302A 2. For example, tucker roll 766/766' and tucker roll 305 can be provided as modular elements of processing system 300. The processing system 300 can further include a pre-heat unit 394 to heat the flexible substrate. Further, a pretreatment plasma source 392 may additionally or alternatively be provided to treat substrates with plasma prior to entering the third chamber portion 302C. The pretreatment plasma source 392 is, for example, an RF (radio frequency) plasma source.
According to yet another embodiment, which can be combined with other embodiments described herein, an optical measurement unit 494 and/or one or more ionization units 492 are also optionally provided. The optical measurement unit 494 is used to evaluate the results of the substrate processing and the ionization unit 492 is used to adapt the charge on the substrate.
According to some embodiments, the deposition material may be selected according to the deposition process and subsequent application of the coated substrate. For example, the deposition material of the deposition source may be selected according to the respective materials of the adhesion-promoting layer 111, the inorganic hard coat top layer 113, the first layer 121, the second layer 122, the third layer 123, the fourth layer 124, and the other adhesion-promoting layer 112 described herein.
Referring illustratively to fig. 8, in accordance with an aspect of the present disclosure, there is provided an optoelectronic device 150 having a hard coating system 100 in accordance with any embodiment described herein. Thus, it will be appreciated that the hard coating system described herein can be advantageously used in optical applications, such as the protection of OLEDs.
Exemplary referring to fig. 9, an embodiment of a method 200 for manufacturing a hard coating system in a continuous roll-to-roll process is described. According to various embodiments, which can be combined with any of the other embodiments described herein, the method 200 includes providing (see block 210) a flexible substrate to at least one first processing region and at least one second processing region without breaking vacuum. Further, the method includes depositing (see block 220) an adhesion-promoting layer on the flexible substrate in at least one first processing region, and depositing (see block 230) an inorganic hardcoat top layer in at least one second processing region.
In particular, depositing the adhesion promoting layer may include forming covalent bonds between the flexible substrate and the adhesion promoting layer. Further, depositing the adhesion promoting layer may include adapting the mechanical properties of the adhesion promoting layer to the mechanical properties of the flexible substrate. For example, the flexibility, e.g., elastic modulus, of the adhesion promoting layer may be adapted to the mechanical properties of the flexible substrate.
According to various embodiments of the method, which may be combined with any of the other embodiments described herein, depositing the adhesion promoting layer and depositing the inorganic hard coat top layer may comprise using a PECVD process and/or a HWCVD (Hot Wire Chemical Vapor Deposition) process. Further, depositing the anti-reflective layer stack 120 may also include utilizing a PECVD process and/or a HWCVD process. For example, the adhesion-promoting layer and/or inorganic hard coat top layer and/or anti-reflective layer stack 120 described herein may be deposited using a low temperature microwave PECVD process.
According to other embodiments of the method, which may be combined with any of the other embodiments described herein, depositing the adhesion promoting layer includes using at least one precursor selected from the group consisting of HMDSO Hexamethyldisiloxane (hexamethiodisiloxane); plasma polymerization of Hexamethyldisiloxane (plasmapolymer Hexamethyl disiloxane) by ppHMDSO; TOMCATS tetramethylcyclotetrasiloxane (C)4H16O4Si4) (ii) a HMDSN Hexamethyldisilazane (Hexamethyldisilazane) ([ (CH)3)3Si]2NH) and TEOS Tetraethoxysilane (TEOS) and Si (OC)2H5)4) The group consisting of.
Further, depositing an inorganic hardcoat top layer can also include utilizingAt least one precursor selected from the group consisting of HMDSO; ppHMDSO; TOMCATS tetramethylcyclotetrasiloxane (C)4H16O4Si4) (ii) a HMDSN Hexamethyldisilazane (Hexamethyldisilazane) ([ (CH)3)3Si]2NH); and TEOS tetraethoxysilane (Si (OC))2H5)4) The group consisting of. In particular, depositing the adhesion-promoting layer and depositing the inorganic hardness top layer may include using the same precursors.
In particular, depositing the adhesion promoting layer may further comprise using at least one agent selected from the group consisting of peroxides as initiator, in particular TBPO (tributylphosphine oxide tert-butyl peroxide); acrylate monomers, particularly ethylhexyl acrylate; and a crosslinking agent, particularly BDDA (butylene glycol diacrylate). Thus, by using at least one agent selected from the above-mentioned group, the adhesion ability of the adhesion promoting layer can be improved. Further, the use of at least one agent selected from the group may be beneficial in improving the structural stability of the hardcoat systems described herein.
In view of the foregoing, it will be appreciated that the various embodiments described herein provide improved hard coating systems and methods for manufacturing such improved hard coating systems, particularly for use in optoelectronic devices such as touch panels.
In conclusion, while the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
In particular, this description uses examples to disclose the disclosure, including the best mode, and also to enable any person skilled in the art to practice the subject matter, including making and using any devices or systems and performing any incorporated methods. Although the foregoing has disclosed various specific embodiments, features of the above-described embodiments that do not violate each other may be combined with each other. The patentable scope is defined by the claims, and other examples are intended to be included within the scope of the claims if the claims have structural elements that do not differ from the literal language of the claims, or if the claims include equivalent structural elements with insubstantial differences from the literal language of the claims.