KR20190058601A - Sapphire thin film coated substrate - Google Patents

Abstract

The composition of the AR layer is intended to match the refractive indices of the lower substrate, for example glass, chemically reinforced glass, plastic, etc., in order to maximize the light transmitted through the AR layer. In the case of a device having a sapphire film for anti-scratching, since the sapphire has a refractive index different from the refractive index of the lower substrate, the conventional AR layer does not function properly; Not only the amount of transmitted light is reduced, but also the transmission range is changed to impair the imaging or display color. Therefore, an AR integrated with a sapphire film having a top AR layer such as Al ₂ O ₃ serving as an anti-scratch layer will eliminate this problem. This aspect involves replacing one of the material of the uppermost layer in the AR AR layer is such that Al ₂ O ₃ which acts as a scratch-resistant layer into Al ₂ O _3.

Description

Sapphire thin film coated substrate

relation Cross reference to application

This application claims the benefit of (1) U.S. Provisional Application No. 62 / 405,215, filed October 6, 2016; (2) U.S. Provisional Application No. 62 / 409,352, filed October 17, 2016; And (3) U.S. Provisional Application No. 13 / 726,127, filed December 23, 2012, which claims priority from U.S. Provisional Application No. 61,579,668, filed December 23, 2011, No. 14 / 642,742, filed March 9, 2014, which claims priority from U.S. Provisional Application No. 13 / 726,183, filed September 12, 2014, and U.S. Provisional Application No. 62 / 049,364, filed September 12, And filed on May 19, 2016, filed on June 19, 2016, filed on September 10, 2015, which claims priority from U.S. Provisional Application No. 62 / 183,182, filed June 22, 2015, Claim 61 / 597,170, filed May 17, 2017, which claims priority from U.S. Provisional Application No. 62 / 339,074 and U.S. Provisional Application No. 62 / 375,433, filed Aug. 15, 2016; The contents of this application are hereby incorporated by reference in their entirety for reference purposes.

Technical field

The present invention relates to the composition of an antireflective (AR) layer aimed at matching the refractive index of a lower substrate such as, for example, glass, chemically tempered glass, plastic, etc., to maximize its light transmittance . For devices with anti-scratch sapphire films, the refractive index of sapphire differs from the refractive index of the substrate, so that the existing AR layer does not function properly. Not only the amount of transmitted light is reduced, but also the transmitted range is changed to impair imaging and / or display color. Therefore, an AR integrated with a sapphire film having a top AR layer such as Al ₂ O ₃ serving as an anti-scratch layer will eliminate this problem. In particular, the invention relates to a method and device for replacing one of the material of the layer such that in AR Al ₂ O ₃ layer is the uppermost AR that serves as a scratch-resistant layer into Al ₂ O _3.

Sapphire is actively considered as a screen for smart phones and tablets. Sapphire is the second hardest material next to diamond, so using it as a screen means that smart phones / tablets have excellent scratch and crack resistant screens. The sapphire screen already has the features of the iPhone 5S TouchID scanner and the camera lens on the back of the phone. Vertu luxury smartphone makers are also developing sapphire screens. However, since sapphire is the second hardest material, it is difficult to cut and shine. Coupled with the fact that it takes time to grow large sized monocrystalline sapphire, results in long manufacturing time and high manufacturing costs. The high manufacturing costs and long manufacturing times of sapphire screens limit Apple to use only those sapphire screens for Apple watches.

Corning 's Gorilla Glass is used in more than 1.5 billion devices as the' tough 'screen material currently in widespread use. Sapphire is actually more difficult to scratch than gorilla glass, which has been proven by some third-party research institutions, such as the Center for Ceramic New Technologies at Alfred University's Kazuo Inamori Institute of Technology. Regarding the Mohs hardness gauge, the latest gorilla glass records 6.5 mos below the morse of fire and mineral quartz. Thus, the gorilla glass is still susceptible to scratching by sand and metal. Sapphire is the second most hard and naturally occurring material on the planet, after diamonds that have recorded 10 on a mode mineral hardness meter.

The Mohs hardness test is intended to characterize the scratch resistance of minerals through the ability of hard materials to scratch soft materials. This test finds the ability of one material to scratch another material, and is thus a better indicator of scratch resistance than breakage resistance. This is shown in FIG.

The following is a quote from the 'Display Review' for the sapphire screen: "Chemically tempered glass can be excellent, but the sapphire is better in terms of hardness, strength, and toughness," explained Hall. The fracture toughness of the sapphire is about four times greater than that of the gorilla glass at about 3 MPa-m0.5 versus 0.7 MPa-m0.5 ".

Yet this brings with it some rather large disadvantages. Sapphire is heavier than 3.98 g per cm 3 (compared to 2.54 g of gorilla glass), as well as slightly more refracting light.

So besides being heavy, the second hardest material, sapphire, is also a difficult material to cut and polish. The growth of single crystal sapphire takes time, especially when the diameter is large (> 6 inches), which is technically very challenging. Therefore, the manufacturing cost is high and the manufacturing time is long with respect to the sapphire screen. It is an object of the present invention to provide a means of manufacturing a sapphire screen material that can be manufactured quickly and at low cost, with the following advantages:

It is harder than any cured glass;

Less likely to be broken than a pure sapphire screen;

It is lighter than a pure sapphire screen;

It has higher transparency than pure sapphire screen.

In order to cure the sapphire (Al ₂ O ₃ ) thin film deposits, the softening / melting temperature of the soft substrate must be sufficiently higher than the annealing temperature. The hardest substrate, such as quartz, fused silica, can meet this requirement. However, flexible substrates such as polyethylene terephthalate (PET) may not meet such requirements. PET has a melting temperature of about 250 ° C, which is well below the annealing temperature. PET is one of the most widely used flexible substrates. The ability to move a substrate of Al ₂ O ₃ (sapphire) thin films onto a soft, flexible substrate can be achieved by transferring the substrate from a rigid substrate such as glass and metals to a flexible substrate such as PET, polymer, plastic, paper, Which greatly expands the application example. The mechanical properties of the transferred substrate can then be improved. Therefore, moving the Al ₂ O ₃ thin film from the rigid substrate to the flexible substrate can circumnavigate the problem of often lowering the melting temperature of the flexible substrate.

An antireflective (AR) layer is commonly used to reduce optical loss or reflection in glass or clear plastic to improve light collection or brighten the display screen. Therefore, the function of the AR layer is to improve the efficiency of imaging and information display, for example. The AR layer generally consists of at least two optically transparent materials with a significant difference in refractive index and forms a periodic structure in depositing alternating layers of these two materials. Interference created within the periodic structure can then improve transmission to a specific transmission range. Nevertheless, the AR layer is vulnerable to scratches. It is therefore an object of the present invention to design an AR layer with an anti-scratch sapphire outer thin film coating that forms part of the AR layer and the optical properties of the common AR layer.

According to a first aspect of the present invention, a method of moving a layer of a rigid thin film substrate onto a soft flexible substrate is provided. In particular, the present invention provides a method of moving a layer of a sapphire thin film to a soft flexible substrate such as, for example, PET, polymer, plastic, paper, and even a fabric. This combination is better than a pure sapphire substrate.

According to a second aspect of the invention, a method of coating a sapphire (Al ₂ O ₃₎ on a flexible substrate it is provided, the method comprising: at least one in order to form at least a first thin-film-coated substrate A first deposition process for depositing at least one first thin film on a first substrate; A second deposition process for depositing at least one second thin film on at least one first thin film coated substrate to form at least one second thin film coated substrate; A third deposition process for depositing at least one catalyst on at least one second thin film coated substrate to form at least one catalyst coated substrate; A fourth deposition process for depositing at least one sapphire (Al ₂ O ₃ ) thin film on at least one catalyst coated substrate to form at least one sapphire (Al ₂ O ₃ ) coated substrate; In order to form at least one hardened sapphire (Al ₂ O ₃ ) thin film coated substrate, at least one sapphire (Al ₂ O ₃ ) coated substrate is heated from 300 ° C. for a duration of time to a sapphire ₂ O ₃ ) at an annealing temperature in the range of less than the melting point of the annealing process; At least one of sapphire (Al ₂ O ₃₎ a step of mounting at least one of the flexible board to the at least one thin film on the hardened sapphire (Al ₂ O ₃₎ thin film; Separating at least one cured sapphire (Al ₂ O ₃ ) thin film together with at least one second thin film from at least one first thin film coated substrate to form at least one second thin film on the at least one flexible substrate, A mechanical separation process for forming a thin film coated cured sapphire (Al ₂ O ₃ ) thin film; And removing at least one second thin film from the at least one second thin film coated cured sapphire (Al ₂ O ₃ ) thin film on the at least one flexible substrate to form at least one sapphire (Al ₂ O ₃ ) thin film coating And an etching process to form the flexible substrate.

In the method according to the second aspect of the invention, said first and / or said flexible substrate comprises at least one material having a morse value less than the morphology of said at least one sapphire (Al ₂ O ₃ ) thin film .

In a first embodiment of the second aspect of the present invention, said first and / or second and / or third and / or fourth deposition process comprises e-beam deposition and / or sputter deposition Is provided.

In a second embodiment of the second aspect of the present invention, the at least one sapphire (Al ₂ O ₃ ) coated substrate and / or at least one cured sapphire (Al ₂ O ₃ ) coated substrate and / A flexible substrate coated with at least one second thin film coated cured sapphire (Al ₂ O ₃ ) thin film and / or at least one sapphire (Al ₂ O ₃ ) thin film on one flexible substrate comprises at least one sapphire ₂ O ₃ ) thin film is provided.

In a third embodiment of the second aspect of the present invention, the thickness of the at least one first substrate and / or the at least one flexible substrate is at least ten times the thickness of the at least one sapphire (Al ₂ O ₃ ) A method of having one or more orders of magnitude is provided.

In a fourth embodiment of the second aspect of the present invention, the thickness of the at least one sapphire (Al ₂ O ₃ ) thin film is less than about 1 mm of the thickness of the at least one first substrate and / or the at least one flexible substrate / 1000 < / RTI >

In a fifth embodiment of the second aspect of the present invention, a method is provided wherein the at least one sapphire (Al ₂ O ₃ ) thin film has a thickness between 150 nm and 600 nm.

In a sixth embodiment of the second aspect of the present invention, a method is provided wherein said effective duration is at least 30 minutes.

In a seventh embodiment of the second aspect of the present invention, a method is provided wherein the effective duration is less than 2 hours.

In an eighth embodiment of the second aspect of the present invention, a method is provided wherein the annealing temperature has a range between 850 캜 and 1300 캜.

In a ninth embodiment of the second aspect of the present invention, a method is provided in which the annealing temperature has a range between 1150 캜 and 1300 캜.

In a tenth embodiment of the second aspect of the present invention, the at least one material is selected from the group consisting of quartz, fused silica, silicon, glass, toughen glass, PET, polymer, plastic, paper, / RTI > A method is provided in which the material for at least one flexible substrate is not etchable by at least one etching process.

In an eleventh embodiment of the second aspect of the invention, the adhesion between the at least one flexible substrate and the at least one cured sapphire (Al ₂ O ₃ ) thin film is greater than the adhesion between the at least one first thin film and the A method stronger than the bonding between two thin films is provided.

In a twelfth embodiment of the second aspect of the present invention, at least one first thin film comprises chromium (Cr) or any material that forms a weaker bond between the at least one first thin film and the at least one second thin film Include; A method is provided in which the material for at least one first thin film is not etchable by at least one etching process.

In a thirteenth embodiment of the second aspect of the present invention, at least one second thin film comprises silver (Ag) or any material that forms a weaker bond between the at least one first thin film and the at least one second thin film Include; A method is provided in which the material for at least one second thin film is etchable by at least one etching process.

In a fourteenth embodiment of the second aspect of the present invention, the at least one catalyst is selected from the group consisting of Ti, Cr, Ni, Si, Ag, Au, (Ge), and a metal having a melting point higher than that of the at least one first substrate.

In a fifteenth embodiment of the second aspect of the present invention, the at least one catalyst coated substrate comprises at least one catalyst film; The at least one catalyst membrane is not continuous; The at least one catalytic membrane has a thickness in the range between 1 nm and 15 nm; Wherein the at least one catalytic membrane comprises a nano-dot having a diameter ranging between 5 and 20 nm.

In a third aspect of the present invention, sapphire is directly deposited on a substrate selected from quartz, fused silica, silicon, glass or tough glass to provide a sapphire coated substrate, and the substrate is not cooled or heated externally during deposition, e A beam deposition or sputter deposition process; And annealing the sapphire-coated substrate for an effective duration of time at an annealing temperature in the range between about room temperature and 2040 占 폚. A method of coating sapphire on a substrate is provided.

In a first embodiment of the third aspect of the present invention, a method is provided for coating sapphire on a substrate, the substrate comprising at least one material having a morse value lower than the morphology of the sapphire.

In a second embodiment of the third aspect of the present invention, a method is provided for coating sapphire on a substrate, wherein the sapphire is deposited as a sapphire thin film on a substrate.

In a third embodiment of the third aspect of the present invention, there is provided a method of coating sapphire on a substrate, wherein the sapphire is deposited as a doped sapphire thin film on a substrate.

In a fourth embodiment of the third aspect of the present invention, the doped sapphire thin film is made of at least one of chromium, chromium oxide, magnesium, magnesium oxide, beryllium, beryllium oxide, lithium, lithium oxide, sodium, There is provided a method of coating sapphire on a substrate, which is doped with a doping element comprising at least one of calcium oxide, molybdenum, molybdenum oxide, tungsten and tungsten oxide.

In a fifth embodiment of the third aspect of the present invention there is provided a method of coating sapphire on a substrate, wherein the ratio of sapphire: doped element is in the range of 1: x and x is in the range of 1 to 3. [

In a sixth embodiment of the third aspect of the present invention, there is provided a method of coating sapphire on a substrate, wherein the thickness of the substrate is at least 10 times greater than the thickness of the sapphire film.

In a seventh embodiment of the third aspect of the present invention, there is provided a method of coating sapphire on a substrate, wherein the thickness of the sapphire film is about 1/1000 of the thickness of the substrate.

In an eighth embodiment of the third aspect of the present invention, there is provided a method of coating sapphire on a substrate, wherein the at least one sapphire film has a thickness between 10 nm and 1000 nm.

In a ninth embodiment of the third aspect of the present invention, there is provided a method of coating sapphire on a substrate, wherein the effective duration is from 30 minutes to 10 hours.

In a tenth embodiment of the third aspect of the present invention, a method is provided for protecting the surface of a substrate by coating the surface with sapphire using the method according to the invention.

In an eleventh embodiment of the second aspect of the present invention, there is provided a screen produced by using the method according to the invention for use in a display.

In a twelfth embodiment of the third aspect of the present invention, there is provided a composition of a sapphire coating produced by the method of the present invention used as a specific index of said sapphire coating.

In a thirteenth embodiment of the third aspect of the present invention, there is provided a sapphire coated substrate produced by the method according to the present invention.

In a fourth aspect of the present invention, a buffer layer is directly deposited on a substrate selected from polymer, plastic, paper, fiber, PMMA or PET to form a buffer coated substrate and the substrate is not cooled or heated externally during deposition, A first e-beam deposition or sputter deposition process at room temperature; And a second e-beam deposition or sputter deposition process at room temperature in which sapphire is directly deposited on the buffer coated substrate to form a sapphire coated substrate and the buffer coated substrate is not externally cooled or heated during deposition Wherein the buffer layer material has a mechanical hardness higher than the substrate and lower than the sapphire, and the buffer layer material has a refractive index larger than the substrate and lower than that of the sapphire.

In a first embodiment of the fourth aspect of the present invention there is provided a method of coating sapphire on a substrate, said buffer layer material having a mechanical hardness in the range of 1 to 5.5 MoS scale.

In a second embodiment of the fourth aspect of the present invention, there is provided a method of coating sapphire on a substrate, wherein the refractive index of the buffer layer material is in the range of 1.45 to 1.65.

In the first embodiment of the fourth aspect of the present invention Example 3, a method of coating a sapphire substrate, in which the buffer layer material comprises silicon dioxide, and SiO ₂ it is provided.

In a fourth embodiment of the fourth aspect of the present invention, a method is provided for protecting the surface of a substrate by coating the surface with sapphire using the method according to the invention.

In a fourth embodiment of the fourth aspect of the present invention, there is provided a screen produced using the method according to the present invention for use in a display.

In a fifth embodiment of the fourth aspect of the present invention, there is provided a sapphire coated substrate produced by the method according to the present invention.

In the fifth aspect of the present invention, it is possible to match the refractive index of a lower substrate such as glass, chemically reinforced glass, plastic or the like with a scratch-resistant sapphire thin film coating on the outermost layer to maximize its light transmittance The composition of the intended AR layer is provided. In a second embodiment of the fifth aspect of the present invention, the sapphire thin film is part of the AR layer relative to the underlying substrate. In a third embodiment of the fifth aspect of the present invention, the lower substrate comprises a flexible material comprising plastic and a metamaterial.

In a sixth aspect of the present invention there is provided an optical waveguide comprising: a top AR material layer comprising sapphire or Al ₂ O ₃ over one or more AR material layers having a higher refraction index of refraction than the top AR material layer; At least one intermediate AR material layer immediately below the uppermost AR material layer and having a higher refractive index than the refractive index of the uppermost AR material layer; And a lowermost AR material layer under one or more intermediate AR material layers deposited on top of the substrate, wherein the top AR material layer, the one or more intermediate AR material layers, and the bottom AR material layer are deposited relative to each other An AR coating on the substrate is provided with alternating high and low refractive indexes.

In a second embodiment of the sixth aspect of the present invention, the second AR material layer has a refractive index in the range of 1.75-1.78 in the visible light region; It may include TiO _2.

In a third embodiment of the sixth aspect of the present invention, the second AR material layer has a refractive index higher than 1.75 in the visible light region; _{YAG, AlAs, ZnSiAs 2, AgBr} , TlBr, C, B 4 C, SiC, AgCl, TlCl, BGO, PGO, CsI, KI, LiI, NaI, RbI, CaMoO 4, SrMoO 4, AlN, GaN, Si 3 N ₄ , LiNbO ₃ , HfO ₂ , Nb ₂ O ₅ , Sc ₂ O ₃ , Y ₂ O ₃ , ZnO, ZrO ₂ , GaP, KTaO ₃ and BaTiO ₃ .

In a fourth embodiment of the sixth aspect of the present invention, the substrate comprises at least one of glass, sapphire, quartz fused silica, plastic and PMMA.

In a fifth embodiment of the sixth aspect of the invention, the bottom material layer of the AR layer structure deposited on top of the substrate is Al ₂ O _3, and; The substrate is not sapphire or Al ₂ O ₃ ; The layered structure may comprise three layers of AR material; Claim 2 AR material layer may include TiO _2.

In a sixth embodiment of the sixth aspect of the present invention, the lowermost AR material layer deposited on top of the substrate is not Al ₂ O ₃ ; The substrate is sapphire or Al ₂ O ₃ ; The layered structure may comprise three layers of AR material; The second AR material layer may comprise TiO ₂ ; The lowermost AR material layer deposited on top of the substrate may comprise MgF ₂ or SiO ₂ depending on the substrate material (e.g. SiO ₂ is not required if the substrate material is glass).

In a seventh embodiment of the sixth aspect of the present invention, the thickness of each of the AR material layers is at least 10 nm.

In an eighth embodiment of the sixth aspect of the present invention, the thickness of each of the AR material layers is 800 nm or less.

In the ninth embodiment of the sixth aspect of the present invention, each of the AR material layers having a low refractive index is made of MgF ₂ , KCl, NaCl, RbCl, CaF ₂ , LaF ₃ , LiF, LiCaAlF ₆ , NaF, RbF, SrF ₂ , ThF _4, it comprises _{YLiF 4, GeO 2, SiO 2} , KH 2 PO 4 and one or more of CS _2.

In a tenth embodiment of the sixth aspect of the present invention, the topmost AR material layer comprises sapphire or Al ₂ O ₃ ; The second AR material layer comprises an AR material having a refractive index higher than the refractive index of the top AR material layer; The lowermost AR material layer is sapphire or Al ₂ O ₃ if the substrate is not sapphire or Al ₂ O ₃ ; The AR material layer on top of the bottom AR material layer comprises an AR material having a refractive index higher than that of the bottom AR material layer.

In an eleventh embodiment of the sixth aspect of the present invention, the topmost AR material layer comprises sapphire or Al ₂ O ₃ ; The second AR material layer comprises an AR material having a refractive index higher than the refractive index of the top AR material layer; AR lowermost material layer and the substrate AR comprises a material having a lower refractive index than the refractive index of the upper right on the AR material of the lowermost layer AR material layer when the sapphire or Al ₂ O _3; The AR material layer on top of the bottom AR material layer comprises an AR material having a refractive index lower than the refractive index of the substrate; The AR material layer on top of the bottom layer of the bottom AR material layer may comprise sapphire or Al ₂ O ₃ .

In a twelfth embodiment of the sixth aspect of the present invention, the layered structure of the AR material layer is fabricated using a physical vapor deposition (PVD) method comprising at least one of electron beam deposition and sputtering.

In a thirteenth embodiment of the sixth aspect of the present invention, a top AR material layer comprising sapphire or Al ₂ O ₃ on top of the bottom AR material layer; A layered structure comprising a lowermost AR material layer deposited on top of a substrate, wherein the topmost AR material layer and the bottommost AR material layer are alternately high and low index of refraction relative to one another.

Those skilled in the art will recognize that variations and modifications other than those specifically described herein may be possible.

The invention includes all such variations and modifications. The present invention also includes any and all combinations or two or more such steps or features, including both steps and features individually or collectively referenced or indicated herein.

Other aspects and advantages of the present invention will become apparent to those skilled in the art upon review of the following description.

(0°로부터 45°까지 변하는)가 PET 기판의 기울기와 입사광의 방향에 의해 정해지는, 실험 도면을 도시한다;
도 20은 Al₂O₃ 박막 이동을 위한 제작 구조물을 도시한다;
도 21은 도너(doner) 기판으로부터 Al₂O₃ 박막을 벗기는 것을 도시한다;
도 22는 PET 기판까지의 Al₂O₃ 박막 이동을 완성하기 위한 희생 Ag 층의 에칭을 도시한다;
도 23은 박막 이동을 위해 준비된 Al₂O₃ 조립체의 제작 샘플을 도시한다;
도 24는 도너 기판으로부터 Al₂O₃를 분리하는 것을 도시한다;
도 25는 상이한 포스트 어닐링(post annealing) 조건을 갖는 소다 라임 유리(SLG) 기판 상의 알루미늄 산화물 막의 나노 압입 결과를 도시한다;
도 26은 사파이어 박막의 상부 상에 증착된 도핑된 알루미늄 산화 막의 샘플의 구조를 도시한다;
도 27은 300℃에서 어닐링한 상이한 강화 층의 나노 압입 측정을 도시한다;
도 28은 상온에서 SLG 및 ASS 상의 1:1(산화 알루미늄:산화 마그네슘) 강화 층의 나노 압입 측정을 도시한다;
도 29는 300℃에서 어닐링한 상이한 강화 층의 투과율을 도시한다;
도 30은 상온에서 SLG 및 ASS 상의 1:1(산화 알루미늄:산화 마그네슘) 강화층의 투과율 결과를 도시한다;
도 31은 상이한 어닐링 온도에서 필드 실리카(field silica, FS) 상의 Al₂O₃:MgO가 1:1인 GID를 도시한다;
도 32는 사파이어 막이 없는, 사파이어 막이 있는 그리고 SiO₂에서 사파이어 막이 있는 선택된 PMMA 샘플의 평균 투과율을 도시한다;
도 33은 사파이어 막이 없는, 사파이어 막이 있는 그리고 SiO₂에서 사파이어 막이 있는 선택된 PMMA 샘플의 평균 경도를 도시한다;
도 34는 긁힘 방지 층뿐만 아니라 최상부 Al₂O₃ AR을 갖는 AR 구조를 도시한다;
도 35는 굴절률이 1.75보다 큰 제2 최외곽 재료를 갖는 AR 구조를 도시한다;
도 36은 유리 기판 상에 TiO₂를 갖는 AR 구조를 도시한다;
도 37은 유리 기판 상에 TiO₂를 갖는 AR 구조의 투과율 시뮬레이션을 도시한다;
도 38은 유리 기판 상에 ZrO₂를 갖는 AR 구조를 도시한다;
도 39는 유리 기판 상에 ZrO₂를 갖는 AR 구조의 투과율 시뮬레이션을 도시한다;
도 40은 유리 기판 상에 HfO₂를 갖는 AR 구조를 도시한다;
도 41은 유리 기판 상에 HfO₂를 갖는 AR 구조의 투과율 시뮬레이션을 도시한다;
도 42은 유리 기판 상에 GaN을 갖는 AR 구조를 도시한다;
도 43은 유리 기판 상에 GaN을 갖는 AR 구조의 투과율 시뮬레이션을 도시한다;
도 44는 사파이어 기판 상의 AR 구조를 도시한다;
도 45는 사파이어 기판 상의 AR 구조의 투과율 시뮬레이션을 도시한다;
도 46은 PMMA 기판 상의 AR 구조를 도시한다;
도 47은 PMMA 기판 상의 AR 구조의 투과율 시뮬레이션을 도시한다;
도 48은 사파이어가 아닌 재료의 기판 상의 3층 AR 구조를 도시한다;
도 49는 사파이어 기판 상의 3층 AR 구조를 도시한다;
도 50은 유리 기판 상의 3층 AR 구조의 투과율 시뮬레이션을 도시한다;
도 51은 사파이어 기판 상의 3층 AR 구조의 투과율 시뮬레이션을 도시한다;
도 52는 150℃의 기판온도에서 마련된 J.Lopez et al.에서의 굴절률을 도시한다;
도 53은 유리 기판 상에 TiO₂ 제2 최외곽 재료를 갖는 3층 AR 구조를 도시한다;
도 54는 증가하는 내부 Al₂O₃ 두께를 갖는 3층 AR의 투과율 시뮬레이션을 도시한다;
도 55는 사파이어 기판 상에 SiO₂를 갖는 3층 AR 구조를 도시한다;
도 56은 사파이어 기판 상에 SiO₂를 갖는 3층 AR 구조의 투과율 시뮬레이션을 도시한다;
도 57은 사파이어 기판 상에 LiF를 갖는 3층 AR 구조를 도시한다;
도 58은 사파이어 기판 상에 LiF를 갖는 3층 AR 구조의 투과율 시뮬레이션을 도시한다;
도 59는 사파이어 기판 상에 KCl을 갖는 3층 AR 구조를 도시한다;
도 60은 사파이어 기판 상에 KCl을 갖는 3층 AR 구조의 투과율 시뮬레이션을 도시한다;
도 61은 유리 기판 상의 5층 AR 구조를 도시한다;
도 62는 사파이어 기판 상의 6층 AR 구조를 도시한다;
도 63은 유리 기판 상의 5층 AR 구조의 투과율 시뮬레이션을 도시한다;
도 64는 사파이어 기판 상의 6층 AR 구조의 투과율 시뮬레이션을 도시한다;
도 65는 사파이어가 아닌 재료의 기판 상의 일반적인 AR 조성을 도시한다;
도 66은 사파이어 기판 상의 일반적인 AR 조성을 도시한다;
도 67은 유리 상에 시뮬레이션되고 실험된 AR 구조에 대한 투과 스펙트럼을 도시한다; 그리고
도 68은 유리 기판 상의 5층 AR 구조의 투과율 시뮬레이션을 도시한다.The above and other objects and features of the present invention will become apparent from the following description of the invention together with the accompanying drawings, in which:
Figure 1 shows the MoScale of mineral hardness;
Figure 2 shows the top surface hardness of " Sapphire thin film on Quartz " as compared to conventional glass, gorilla glass, quartz, and pure sapphire;
3 shows the light transmittance of a quartz and sapphire thin film on quartz and pure sapphire;
4 shows that the light transmittance of quartz and the light transmittance of a 190 nm sapphire thin film on quartz are not annealed at 1300 캜 for 2 hours;
Figure 5 shows the XRD results for a 400 nm sapphire thin film on quartz annealed at 750 ° C, 850 ° C, and 1200 ° C for 2 hours;
Figure 6 shows the transmission spectrum of a 400 nm sapphire thin film on quartz by an e-beam unannealed and annealed at 1200 캜 for 2 hours, compared to a quartz and sapphire substrate;
Figure 7 shows the transmission spectrum of a 160 nm sapphire thin film on fused silica by annealing at 1150 캜 for 2 hours and by non-annealed e-beam compared to quartz and sapphire substrates;
8A shows the XRD results for a 400 nm sapphire thin film on quartz prepared by annealing and sputter depositing at 850 ° C, 1050 ° C, and 1200 ° C for 2 hours;
Figure 8b shows the XRD results for a sapphire thin film with thicknesses of 220 nm, 400 nm, and 470 nm on quartz prepared by annealing and sputtering at 1150 ° C for 2 hours;
Figure 9 shows the transmission spectra of 220 nm, 400 nm and 470 nm sapphire films on quartz by annealing and sputter depositing at 1100 ° C for 2 hours, compared to a quartz substrate;
10 shows XRD results of a 350 nm sapphire film on fused silica prepared by annealing and sputtering at 750 DEG C, 850 DEG C, 1050 DEG C, and 1150 DEG C for 2 hours;
11 shows the transmission spectrum of a 180 nm to 600 nm sapphire film on fused silica by annealing and sputtering at 1150 ° C for 2 hours as compared to a fused silica substrate;
12 shows the transmittance of fused silica with a 250 nm annealed sapphire film with or without a 10 nm Ti catalyst on fused silica annealed at 700 < 0 > C and 1150 < 0 > C for 2 hours;
Figure 13a shows the X-ray reflectance (XRR) measurement results for different samples with different annealing conditions;
Figure 13b shows the optical transmission spectrum for different samples with different annealing conditions;
Figs. 14A to 14E are diagrams for explaining a case where a disk-array device has a period of 600 nm, a disk diameter of 365 nm, a thickness of gold of 50 nm and a thickness of Cr of 30 nm Showing the EBL step in fabrication; 14a illustrates that a multi-layer plasmonic or meta-material device is fabricated on chrome coated quartz; Figure 14b shows a gold / ITO thin film being deposited on the Cr surface; 14C shows that a ZEP520A (positive e-beam resist) thin film rotates on top of an ITO / gold / Cr / quartz substrate and a two-dimensional hole array is obtained in ZIP520A; 14d shows the second gold thin film being coated on the e-beam patterned resist; 14E shows that a two-dimensional gold disk-array nanostructure is formed by removing resist residues;
14f shows a scanning electron microscope (SEM) image of a two-dimensional gold disk-array absorber meta-material;
15A to 15E show schematic drawings of a flip chip transfer method in which a three-layered absorber meta-material having an area of 500 mu m x 500 mu m is transferred to a PET flexible substrate; 15A shows that a double-sided adhesive and optically transparent adhesive is attached to the PET substrate; FIG. 15B shows a three-layered metamaterial device according to an embodiment of the present invention in intimate contact with an optical adhesive and sandwiched between an optical adhesive and a rigid substrate; FIG. 15C shows that a Cr thin film on a quartz substrate is exposed to air for several hours after the RF sputtering process to form a thin natural oxide film on the Cr surface; 15D shows that a three-layered metamaterial nanostructure is peeled from a Cr coated quartz substrate and transferred to a PET substrate; 15E shows that a metamaterial nanostructure is encapsulated by spin-coating a PMMA layer on top of the device;
Figures 16a and 16b show flexible NIR absorber meta-materials on a transparent PET substrate, with each discrete pattern having an area size of 500 占 퐉 x 500 占 퐉;
Figure 17 shows that the NIR light is focused on an ordinary device, the reflected signal is collected by an objective lens 15 times (15X), the blue line is the experimental result, and the red line is simulated using the RCWA method (Gold disk / ITO / gold / Cr / quartz) on the quartz substrate, which is the reflection spectrum of the absorber meta-material;
18A is an angled resolved backside reflectance spectrum measured for a flexible metamaterial (with curved surface), showing that light is incident from the PET side and the back reflection is collected by the NIR detector do;
18B shows the transmission spectrum measured for the flexible absorber meta-material, in which light is incident from the PMMA side and collected from the PET side;
Figures 18c and 18d show the simulated reflection spectra and transmittance spectra for the flexible absorber meta-material, respectively, using the RCWA method;
19 is an experimental view for measuring the reflection spectrum of the meta-material device under different bending conditions, wherein the flexible substrate is bent by adjusting the distance between A and B,

(Varying from 0 DEG to 45 DEG) is determined by the slope of the PET substrate and the direction of the incident light;
Figure 20 shows the fabrication structure for Al ₂ O ₃ thin film transport;
Figure 21 shows stripping of Al ₂ O ₃ thin film from a donor substrate;
22 shows the etching of the sacrificial Ag layer to complete the Al ₂ O ₃ thin film transfer to the PET substrate;
Figure 23 shows a production sample of an Al ₂ O ₃ assembly prepared for thin film transfer;
Figure 24 shows the separation of Al ₂ O ₃ from the donor substrate;
Figure 25 shows the result of nanoindentation of an aluminum oxide film on a soda lime glass (SLG) substrate with different post annealing conditions;
26 shows the structure of a sample of a doped aluminum oxide film deposited on top of a sapphire thin film;
27 shows nanoindentation measurements of different enhancement layers annealed at 300 < 0 >C;
Figure 28 shows nanoindentation measurements of a 1: 1 (aluminum oxide: magnesium oxide) reinforcing layer on SLG and ASS at room temperature;
29 shows the transmittance of the different enhancement layers annealed at 300 [deg.] C;
30 shows the transmittance results of a 1: 1 (aluminum oxide: magnesium oxide) reinforcing layer on SLG and ASS at room temperature;
Figure 31 shows GID with 1: 1 Al ₂ O ₃ : MgO on field silica (FS) at different annealing temperatures;
32 shows the average transmittance of a selected PMMA sample with and without a sapphire film and with a sapphire film at a SiO ₂ ;
33 shows the average hardness of a selected PMMA sample with a sapphire film and without sapphire film and with a sapphire film at SiO ₂ ;
Figure 34 shows an AR structure with top Al ₂ O ₃ AR as well as an anti-scratch layer;
Figure 35 shows an AR structure with a second outermost material with a refractive index greater than 1.75;
Figure 36 shows an AR structure with TiO ₂ on a glass substrate;
Figure 37 shows a transmission simulation of an AR structure with TiO ₂ on a glass substrate;
38 shows an AR structure with ZrO ₂ on a glass substrate;
Figure 39 shows a transmission simulation of an AR structure with ZrO ₂ on a glass substrate;
Figure 40 shows an AR structure with HfO ₂ on a glass substrate;
41 shows a transmission simulation of an AR structure with HfO ₂ on a glass substrate;
Figure 42 shows an AR structure with GaN on a glass substrate;
Figure 43 shows a transmission simulation of an AR structure with GaN on a glass substrate;
44 shows an AR structure on a sapphire substrate;
45 shows a transmission simulation of an AR structure on a sapphire substrate;
46 shows an AR structure on a PMMA substrate;
Figure 47 shows a transmission simulation of an AR structure on a PMMA substrate;
Figure 48 shows a three layer AR structure on a substrate of non-sapphire material;
49 shows a three layer AR structure on a sapphire substrate;
Figure 50 shows the transmission simulation of a three layer AR structure on a glass substrate;
Figure 51 shows the transmission simulation of a three layer AR structure on a sapphire substrate;
Figure 52 shows the refractive index in J.Lopez et al. Prepared at a substrate temperature of 150 캜;
53 shows a three-layer AR structure having a TiO ₂ second outermost material on a glass substrate;
54 shows a transmission simulation of a three layer AR with increasing internal Al ₂ O ₃ thickness;
55 shows a three layer AR structure with SiO ₂ on a sapphire substrate;
56 shows a transmission simulation of a three layer AR structure with SiO ₂ on a sapphire substrate;
57 shows a three layer AR structure with LiF on a sapphire substrate;
Figure 58 shows the transmission simulation of a three layer AR structure with LiF on a sapphire substrate;
59 shows a three layer AR structure with KCI on a sapphire substrate;
Figure 60 shows the transmission simulation of a three layer AR structure with KCI on a sapphire substrate;
61 shows a 5-layer AR structure on a glass substrate;
62 shows a six layer AR structure on a sapphire substrate;
63 shows the transmission simulation of a 5-layer AR structure on a glass substrate;
64 shows the transmission simulation of a 6-layer AR structure on a sapphire substrate;
65 illustrates a typical AR composition on a substrate of a material other than sapphire;
Figure 66 shows a typical AR composition on a sapphire substrate;
67 shows the transmission spectrum for an AR structure simulated and tested on glass; And
68 shows the transmission simulation of a 5-layer AR structure on a glass substrate.

The present invention is not to be limited in scope by any of the specific embodiments described herein. The following embodiments are provided for illustrative purposes only.

Without wishing to be bound by theory, the inventors of the present invention have discovered through their attempts, experiments, and studies that a layer of a more rigid thin film substrate on a soft, flexible substrate such as PET, polymer, plastic, paper, To complete the work of moving. This combination is better than a pure sapphire substrate. In fact, the harder the material, the deeper the material is, the more fragile the sapphire substrate is, the more difficult it is to scratch, but it is easily broken, and the quartz substrate is easier to scratch but less broken than the sapphire substrate. Hence depositing a harder thin film substrate on a soft, flexible substrate results in a single gain. Soft and flexible substrates are less brittle, have good mechanical performance, and are less costly. The function of scratch prevention should be performed by using a harder thin film substrate. For curing of the sapphire (Al ₂ O ₃ ) thin film deposition, the softening / melting temperature of the soft substrate must be sufficiently higher than the annealing temperature. Most rigid substrates such as quartz and fused silica can meet these requirements. However, flexible substrates such as polyethylene terephthalate (PET) can not meet these requirements. PET has a melting temperature of about 250 ° C below the annealing temperature. PET is one of the most widely used flexible substrates. The ability to move a substrate of Al ₂ O ₃ (sapphire) thin film onto a soft, flexible substrate can be used to transport substrates from rigid substrates such as glass and metals to flexible substrates such as PET, polymers, plastics, paper, To a large extent. The mechanical properties of the transferred substrate can be improved. Moving the Al ₂ O ₃ thin films from a rigid substrate to a flexible substrate can therefore often avoid the problems of lower melting temperatures of flexible substrates.

According to a first aspect of the present invention, there is provided a method of coating / depositing / transferring a layer of a rigid thin film substrate onto a soft flexible substrate. In particular, the present invention provides a method of depositing a layer of a sapphire thin film on a soft flexible substrate such as, for example, PET, polymer, plastic, paper, and fabric. This combination is better than a pure sapphire substrate.

According to a second aspect of the invention, a method of coating a sapphire (Al ₂ O ₃₎ on a flexible substrate it is provided, the method comprising: at least one in order to form at least a first thin-film-coated substrate A first deposition process for depositing at least one first thin film on a first substrate; A second deposition process for depositing at least one second thin film on at least one first thin film coated substrate to form at least one second thin film coated substrate; A third deposition process for depositing at least one catalyst on at least one second thin film coated substrate to form at least one catalyst coated substrate; A fourth deposition process for depositing at least one sapphire (Al ₂ O ₃ ) thin film on at least one catalyst coated substrate to form at least one sapphire (Al ₂ O ₃ ) coated substrate; In order to form at least one hardened sapphire (Al ₂ O ₃ ) thin film coated substrate, at least one sapphire (Al ₂ O ₃ ) coated substrate is heated from 300 ° C. for a duration of time to a sapphire ₂ O ₃ ) at an annealing temperature in the range of less than the melting point of the annealing process; Attaching at least one flexible substrate to at least one cured sapphire (Al ₂ O ₃ ) thin film on at least one sapphire (Al ₂ O ₃ ) thin film; Separating at least one cured sapphire (Al ₂ O ₃ ) thin film together with at least one second thin film from at least one first thin film coated substrate to form at least one second thin film on the at least one flexible substrate, A mechanical separation process for forming a thin film coated cured sapphire (Al ₂ O ₃ ) thin film; And removing at least one second thin film from the at least one second thin film coated cured sapphire (Al ₂ O ₃ ) thin film on the at least one flexible substrate to form at least one sapphire (Al ₂ O ₃ ) thin film coating And an etching process to form the flexible substrate.

In the method according to the invention, said first and / or said flexible substrate comprises at least one material having a morse value less than that of said at least one sapphire (Al ₂ O ₃ ) thin film.

In a first embodiment of the second aspect of the present invention, a method is provided wherein said first and / or second and / or third and / or fourth deposition process comprises e-beam deposition and / or sputter deposition .

In a second embodiment of the second aspect of the present invention, the at least one sapphire (Al ₂ O ₃ ) coated substrate and / or at least one cured sapphire (Al ₂ O ₃ ) coated substrate and / A flexible substrate coated with at least one second thin film coated cured sapphire (Al ₂ O ₃ ) thin film and / or at least one sapphire (Al ₂ O ₃ ) thin film on one flexible substrate comprises at least one sapphire ₂ O ₃ ) thin film is provided.

In a third embodiment of the second aspect of the present invention, the thickness of the at least one first substrate and / or the at least one flexible substrate is at least ten times the thickness of the at least one sapphire (Al ₂ O ₃ ) Or more is provided.

In a fourth embodiment of the second aspect of the present invention, the thickness of the at least one sapphire (Al ₂ O ₃ ) thin film is less than about 1 mm of the thickness of the at least one first substrate and / or the at least one flexible substrate / 1000 < / RTI >

In a fifth embodiment of the second aspect of the present invention, a method is provided wherein the at least one sapphire (Al ₂ O ₃ ) thin film has a thickness between 150 nm and 600 nm.

In a sixth embodiment of the second aspect of the present invention, a method is provided wherein said effective duration is at least 30 minutes.

In a seventh embodiment of the second aspect of the present invention, a method is provided wherein the effective duration is less than 2 hours.

In an eighth embodiment of the second aspect of the present invention, a method is provided wherein the annealing temperature has a range between 850 캜 and 1300 캜.

In a ninth embodiment of the second aspect of the present invention, a method is provided in which the annealing temperature has a range between 1150 캜 and 1300 캜.

In a tenth embodiment of the second aspect of the present invention, the at least one material comprises quartz, fused silica, silicon, glass, tough glass, PET, polymer, plastic, paper, fabric or any combination thereof; A method is provided in which the material for at least one flexible substrate is not etchable by at least one etching process.

In an eleventh embodiment of the second aspect of the invention, the adhesion between the at least one flexible substrate and the at least one cured sapphire (Al ₂ O ₃ ) thin film is greater than the adhesion between the at least one first thin film and the A method stronger than the bonding between two thin films is provided.

In a twelfth embodiment of the second aspect of the present invention, at least one first thin film comprises chromium (Cr) or any material that forms a weaker bond between the at least one first thin film and the at least one second thin film Include; A method is provided in which the material for at least one first thin film is not etchable by at least one etching process.

In a thirteenth embodiment of the second aspect of the present invention, at least one second thin film comprises silver (Ag) or any material that forms a weaker bond between the at least one first thin film and the at least one second thin film Include; A method is provided in which the material for at least one second thin film is etchable by at least one etching process.

In a fourteenth embodiment of the second aspect of the present invention, the at least one catalyst is selected from the group consisting of Ti, Cr, Ni, Si, Ag, Au, (Ge), and a metal having a melting point higher than that of the at least one first substrate.

In a fifteenth embodiment of the second aspect of the present invention, the at least one catalyst coated substrate comprises at least one catalyst film; The at least one catalyst membrane is not continuous; The at least one catalytic membrane has a thickness in the range between 1 nm and 15 nm; Wherein the at least one catalytic film comprises nanodots having diameters in the range between 5 nm and 20 nm.

Justice

For clarity and completeness, the following definitions of terms are used in this disclosure:

The word "sapphire" used herein to refer to a material or substrate, such a material or substrate comprising different ones having impurities, aluminum oxide (alpha -Al ₂ O _3), alumina, or in the material, or substrate It is also known as the gem stone variety of mineral corundum. Pure Corundum (Aluminum Oxide) is colorless or corundum with a maximum of 0.01% titanium. The various sapphire colors arise from the presence of different chemical impurities or trace elements:

Blue sapphire is typically colored by traces of iron and titanium (only 0.01%).

The combination of iron and chromium produces yellow or orange sapphire.

Chrome alone makes pink or red (ruby); In the case of deep red ruby, there is at least 1% chromium.

Iron alone produces weak yellow or green.

Violet or purple sapphire is colored by vanadium.

As used herein, the term " harder " refers to the relative measure of the hardness of a material as compared to others. For the sake of clarity, if the first material or substrate is defined as being stiffer than the second material or substrate, the morse value for the first material or substrate is higher than the morse value for the second material or substrate.

As used herein, the term " softer " refers to the relative degree of hardness of a material as compared to others. For the sake of clarity, if the first material or substrate is defined as being smoother than the second material or substrate, the morse value for the first material or substrate is lower than the morse value for the second material or substrate.

As used herein, the term " flexible " refers to the mechanical properties of a substrate, which may be physically steered to change its physical shape using force without breaking the substrate .

The term " screen " as used herein in the present specification refers to a cover-glass, a cover-screen, a cover window, a display screen, a display window, a cover surface or a cover plate of a device. For the sake of clarity, in many cases the screen on a given device has a dual function of displaying the interface of the device and protecting the surface of the device, in which case good light transmission is a necessary feature of the screen, . In other cases where only the function of providing surface protection is required, the light transmittance of the screen is not essential.

In one embodiment of the present invention, a method of developing a harder and better transparent screen than a gorilla glass is provided, and such a transparent screen is comparable to a pure sapphire screen, but has the following advantages:

It is harder than any cured glass;

Less likely to be broken than a pure sapphire screen;

It is lighter than a pure sapphire screen;

It has higher transparency than pure sapphire screen.

In one embodiment of the present invention, a method of depositing a sapphire thin film on a quartz substrate is provided. With a post-deposit treatment such as thermal annealing, one embodiment of the present invention achieves an upper surface hardness of up to 8 to 8.5 Mohs, which is close to a sapphire single crystal hardness of 9 mos. One embodiment of the invention herein is known as " quartz-like sapphire thin film ". Figure 2 shows the top surface hardness of a " quartz sapphire thin film " compared to conventional glass, gorilla glass, quartz and pure sapphire.

The quartz substrate itself is a single crystal of SiO ₂ having a morse value higher than that of glass. Its melting point is 1610 ° C, which can withstand high annealing temperatures. In addition, such a substrate can be cut to a desired size such that one embodiment of the present invention can deposit a sapphire thin film. The thickness of the deposited sapphire film is 1/1000 of that of the quartz substrate alone. The cost of the synthetic quartz crystals is relatively low (which is only less than US $ 10 / kg at the time the present invention is disclosed herein). Thus, in one embodiment of the present invention, fabrication cost and fabrication time are significantly reduced compared to fabrication of pure sapphire substrates.

The invention Example  Features and Benefits

Hardness higher than hardened glass

In one embodiment of the present invention, the developed quartz sapphire thin film has a maximum value of 8.5 mos in the upper surface hardness. The gorilla glass used in the recent spot phone screens recorded only about 6.5 mos in hardness value and the natural quartz substrate had a hardness value of 7 mos. Therefore, the present invention achieves a significant improvement in the upper surface hardness compared with the state of the art. The quartz sapphire thin film has a hardness value of 8.5 mos, which is very close to the pure sapphire hardness value of 9 mos, and the quartz sapphire thin film has the advantages of low manufacturing cost and less time to manufacture.

Less crushed than sapphire light

In fact, the harder the material, the more fragile the material is, and thus the sapphire substrate is difficult to scratch but easily crumpled, and vice versa. Quartz has a relatively low elastic modulus, which makes it much more shock resistant than sapphire.

Further, in one embodiment of the present invention, the deposited sapphire film is very thin compared to a quartz substrate, and the deposited sapphire film is only 1/1000 of the quartz substrate thickness. Therefore, the total weight of the quartz sapphire thin film is almost the same as that of the quartz substrate, which is only 66.6% (2/3) of the weight of a pure sapphire substrate having the same thickness. This is because the density of quartz is 2.65 g / cm3, the sapphire is 3.98 g / cm3, and the gorilla glass is 2.54 g / cm3. In other words, quartz substrates are 4.3 times heavier than gorilla glass, whereas pure sapphire substrates are roughly 1.5 times heavier than gorilla glass and quartz. Table 1 shows a comparison between the density of quartz, gorilla glass and pure sapphire.

Table 1: Density comparison of gorilla glass, quartz, and pure sapphire and their percentage difference.

US patent application Ser. No. 13 / 783,262, filed recently by the company, also discloses a sapphire and glass layer that produces sapphire laminated glass to combine the advantages of glass's weight and flexibility with the durability of sapphire And that they have designed a way to dissolve them together. However, it is very difficult to polish thin (<0.3 mm) sapphire substrates with larger areas (> 6 inches). Therefore, using a quartz-like sapphire thin film is the best combination for screen with lighter weight, higher top surface hardness, less shattered substrate.

Transparency higher than pure sapphire

Since the refractive indices of sapphire crystal, quartz crystal and gorilla glass are respectively 1.76, 1.54 and 1.5, their total light transmittance is 85%, 91% and 92% due to Fresnel reflection loss. This means that there is a trade-off between light transmittance and durability. Sapphire can transmit less light, resulting in dimmer devices or shorter device battery life. When more light is transmitted, more energy is saved and the device battery life becomes longer. 3 shows the light transmittance of quartz, quartz sapphire thin film and pure sapphire.

Most crystals, including sapphire and quartz, have birefringence problems. By comparing the refractive index (n ₀ , n _e ) with respect to the normal ray and the extraordinary ray, the magnitude of the difference (n) is quantified by birefringence. In addition, the value of [Delta] n in one embodiment of the present invention is also small such that such a birefringence problem is not significant for applications having thinner substrate thicknesses (~ 1 mm). For example, pure sapphire is used as a camera cover lens on Apple's iPhone 5S, which does not report any blurred images. Table 2 shows the refractive indices (n ₀ , n _e ) of normal and extraordinary rays and their difference (Δn) in birefringence with respect to quartz and sapphire.

Table 2: refractive index (n ₀ , n _e ) of normal and extraordinary rays and their difference (Δn) with respect to quartz and sapphire.

Better production times and lower production costs than pure sapphire

In recent years, both synthetic sapphire and quartz monocrystals have grown and are commercially available. Because sapphire has a higher melting point than quartz, the growth of sapphire is more difficult and more expensive. More importantly, the time to grow the sapphire is much longer than quartz. It is difficult to grow sapphire for products larger than 6 inches, and a limited number of companies can achieve this. Therefore, it limits the production rate so that the manufacturing cost of the sapphire substrate is higher than that of quartz. Table 3 shows the formula, melting point, and Mohs hardness values for quartz and sapphire.

Table 3: Formula, melting point, and Mohs hardness values for quartz and sapphire.

Another difficulty in using pure sapphire is that sapphire crystals with a hardness value of 9 mos are very difficult to cut and polish. So far, it is very difficult to have a shiny (<0.3 mm) sapphire substrate with a larger area (> 6 inches). The successful ratio is not too high, which prevents the sapphire substrate from falling too much even though a larger number of sapphire crystal growth furnaces are now operating. Corning claims that sapphire screens can cost up to 10 times more than gorilla glass. On the other hand, quartz has a Mohs hardness value of 7 and is easier to cut and polish. In addition, the cost of synthetic quartz crystals is relatively less expensive (less than US $ 10 / kg at the time of this disclosure).

The additional cost of the quartz sapphire film is therefore the cost of depositing the sapphire film on the quartz substrate and post-treatment of the quartz sapphire film. In one embodiment of the present invention, when all conditions are optimized, the mass production process can be fast and the cost is low.

In one embodiment of the present invention, a method of depositing a harder sapphire thin film on a quartz substrate is provided. The thickness of this thin film ranges between 150 nm and 1000 nm. With a post-deposition treatment such as thermal annealing at 500 ° C to 1300 ° C, embodiments of the present invention achieve a hardness of 8 to 8.5 mos very close to 9 mos, which is a sapphire single crystal hardness. In another embodiment of the present invention, it has been found that, with an achieved hardness value of 8 to 8.5 mos very close to 9 mos, which is a sapphire single crystal hardness, the thickness ranges between 150 nm and 500 nm, A sapphire thin film having optical performance is provided. The annealing temperature ranges between 1150 ° C and 1300 ° C. 4 shows the case where the light transmittance of quartz and the case where the light transmittance of the sapphire thin film of 190 nm on the quartz surface are annealed at 1300 캜 for 2 hours and not. Therefore, from a hardness point of view, the sapphire thin film on quartz is comparable to that of a pure sapphire screen and its weight is approximately the same as that of a glass / quartz substrate which is approximately 66.6% of the weight of a pure sapphire substrate, Cm &lt; 3 &gt;, and sapphire is 3.98 g / cm &lt; 3 &gt;. Since anyone can cut the substrate to a desired size according to the method and then deposit the sapphire thin film, the fabrication cost and time are significantly reduced compared to the case of a pure sapphire substrate.

In fact, the value of the hardness of the sapphire film by e-beam deposition is not too high. In one embodiment of the invention, the value of the hardness was measured to be less than 7 mos. However, after the thermal annealing process, the film hardness was significantly improved. In one embodiment of the present invention, it was found that the sapphire thin film was softened by annealing at 1300 캜 for 2 hours. The film thickness was reduced by about 10%, and the film hardness was improved from 8 to 8.5 mos. Since the quartz substrate is a single crystal of SiO ₂ having a melting point of 1610 ° C, it can withstand a high annealing temperature. Therefore, the hardness of the sapphire thin film on the annealed quartz substrate can reach up to 8.5 mos. 4 shows the transmittance of a 190 nm sapphire thin film on quartz and the transmittance of quartz in the case of annealing at 1300 캜 for 2 hours and in the case of not annealing.

Further, in another embodiment of the present invention, the annealing process of the sapphire thin film is also performed on other substrates. For example, a sapphire thin film annealed at 1000 ° C on a fused silica substrate and a sapphire thin film annealed at 500 ° C on a glass substrate, their hardness was measured.

Electron beam (E-beam) and sputter deposition are two of the most widely used methods of depositing a sapphire thin film on quartz and other related substrates. In an embodiment of the present invention, these two common deposition methods are used.

Sapphire Thin Films by e-beam Deposition

Summary points for sapphire film deposition on a given substrate by e-beam deposition are given as follows:

The deposition of the sapphire thin film uses e-beam evaporation because aluminum oxide has a very high melting point at 2040 ° C. White pellets or colorless crystals of pure aluminum oxide are used as e-beam evaporation sources. The high melting point of the aluminum oxide also allows the annealing temperature to be below the melting point of the maximal sapphire (e.g. 2040 ° C at atmospheric pressure).

The substrates are held vertically on the sample holder far further away than the evaporation source 450 mm. The sample holder is rotated at 1 to 2 RPM when deposition occurs.

The base vacuum of the evaporation chamber is less than 5 × 10 ^-6 torr and the vacuum is maintained below 1 × 10 ^-5 torr when deposition occurs.

The thickness of the film deposited on the substrate is about 150 nm to 1000 nm. The deposition rate is about 1-5 A / s. The substrate under deposition has no external cooling or heating. The film thickness is measured by an ellipsometry method and / or a scanning electron microscope (SEM).

Higher temperature film deposition is possible from room temperature to 1000 ° C.

A more detailed description of the process of e-beam deposition for a sapphire thin film on another substrate is given below:

1) Deposition of the sapphire thin film uses e-beam evaporation because aluminum oxide has a high melting point of 2040 ° C. The aluminum oxide pellets are used as e-beam evaporation sources. The high melting point of the aluminum oxide also allows the annealing temperature to be below the melting point of the maximum sapphire (e.g., 2040 ° C at atmospheric pressure).

2) The coated substrate is vertically fixed on the sample holder, far away from the evaporation source 450 mm. The sample holder is rotated at 2 RPM when deposition occurs.

3) The thickness of the film deposited on the substrate is between about 190 nm and 1000 nm. The deposition rate is about 1 Å / s. The substrate during deposition has no external cooling or heating. The film thickness is measured by an ellipsometric method.

4) After the sapphire thin film is deposited on the substrate, it is annealed by the furnace from 500 ° C to 1300 ° C. The temperature rising rate is 5 占 폚 / min and the temperature lowering rate is 1 占 폚 / min. The time to maintain a certain thermal annealing temperature ranges from 30 minutes to 2 hours.

5) The deposition substrate includes quartz, fused silica, and (tempered) glass. Their melting points are 1610 캜, 1140 캜 and 550 캜, respectively. The annealing temperatures of the sapphire thin films coated on them are 1300 ° C, 1000 ° C and 500 ° C, respectively.

6) The transmittance of quartz and the transmittance of a 190 nm sapphire thin film on quartz are shown in FIG. 4 for cases of annealing at 1300 占 폚 for 2 hours. The percentage of light transmission in the entire visible range from 400 nm to 700 nm is greater than 86.7%, at most up to 91.5% at 550 nm, while the percentage of light transmission for pure sapphire substrates is only 85 to 86%. A large amount of transmitted light indicates that more energy is saved from the backlight-source of the display panel, thus increasing the battery life of the device.

The invention Example Annealing  fair

After deposition of the sapphire thin film on the substrate, the sapphire thin film is annealed in the furnace from 500 ° C to 1300 ° C. The temperature rising rate is 5 占 폚 / min and the temperature lowering rate is 1 占 폚 / min. The time to maintain a certain thermal annealing temperature ranges from 30 minutes to 2 hours. In order to improve hardness and also to reduce microcracks in the thin film, multiple steps of annealing at different temperatures within the above range are also used. Table 4 shows the surface hardness and XRD characteristic peaks at different annealing temperatures provided by e-beam deposition. The table also shows the crystalline phases of the various sapphires present in the films; Most common phases are alpha (alpha), theta (theta), and delta (delta).

Table 4: Surface hardness and XRD characterization peaks at different annealing temperatures provided by e-beam deposition.

Table 4 shows the surface hardness variation of the sapphire thin film as a function of the annealing temperature varying from 500 캜 to 1300 캜. In fact, the initial value of the hardness of the e-beam deposited sapphire film without annealing is about 5.5 mos. However, after the thermal annealing process, the film hardness is significantly improved. With respect to the annealing temperature in the range of 500 캜 to 850 캜, 850 캜 to 1150 캜 and 1150 캜 to 1300 캜, the hardness values of the quartz sapphire thin film are respectively 6 to 7 mos, 7 to 8 mos , And 8 to 8.5 mos.

Figure 5 shows the XRD results for a 400 nm sapphire thin film on quartz annealed at 750 ° C, 850 ° C and 1200 ° C for 2 hours. When the annealing temperature is higher than 850 DEG C, the film starts to partially crystallize. The formation of new XRD peaks corresponds to the mixing of the theta and delta structural phases of aluminum oxide.

When annealing above 1300 ° C, the film begins to evolve into some larger crystallites that can scatter visible light considerably; This reduces the transmittance intensity. In addition, these larger crystallizers become more and more deposited, the membrane becomes cracked, and some micro-sized pieces fall off the substrate.

In one embodiment of the present invention, it has been discovered that a sapphire thin film on a quartz substrate can be annealed from 1150 ° C to 1300 ° C within 30 minutes to 2 hours. The film thickness is reduced by about 10%, and the film hardness is improved to 8 to 8.5 mos. Since the quartz substrate is monocrystalline SiO ₂ with a melting point of 1610 ° C, it can withstand such high annealing temperatures. Under these annealing temperatures, the hardness of the annealed sapphire film on the quartz substrate achieved 8.5 mos.

The light transmittance of a 400 nm sapphire thin film on quartz in the case of annealing at 1200 ° C. for 2 hours and in the case of no annealing is shown in FIG. 6 and is compared with the case of a quartz substrate and a sapphire substrate. The light transmittance of the quartz sapphire thin film in the visible region between 400 nm and 700 nm is greater than 88% and reaches a maximum of 92% at 550 nm. The interference pattern is due to the difference between the refractive index of the material and the film thickness. The overall average light transmittance is about 90%, whereas the pure sapphire substrate is only 85 to 86%. In addition, the light transmission spectrum of a quartz sapphire thin film coincides with that of a quartz substrate at a specific wavelength, which indicates that the optical performance is excellent and the scattering loss is low. The difference between the maximum intensity and the minimum intensity of the interference pattern is only about 4%. In practical applications, the more light transmitted, the more energy is saved from the backlight source of the display panel, resulting in a longer battery life of the device.

Thickness of quartz sapphire thin film

A quartz-like sapphire thin film having a thickness between 150 nm and 1000 nm was tested. In one embodiment of the present invention, a sapphire thin film having a thickness between 150 nm and 500 nm is provided, and this thin film has good optical performance with low scattering loss when the annealing temperature is between 1150 ° C and 1300 ° C. However, when the thickness is larger than 600 nm, the film is split, causing significant scattering, which reduces the transmittance intensity.

For a sapphire thin film having a thickness between 150 nm and 500 nm deposited on quartz after annealing between 1150 and 1300 ° C, the measured hardness can achieve 8 to 8.5 mos, which is much thinner And even a coating film can act as an anti-scratch layer.

Other possible substrates for scratch-resistant coatings

In addition to the quartz substrate, another embodiment of the present invention also investigated the deposition of a sapphire thin film on different substrates such as fused silica and silicon. Transparent ceramic substrates or other tempered glass with a higher annealing or melting temperature capable of withstanding an annealing temperature of 850 캜 within a period of between 30 minutes and 2 hours can increase their surface hardness to 7 to 8 on a Mohs hardness scale Lt; / RTI &gt; can also be used as substrates. For example, Schott Nextrema transparent ceramics have short heating temperatures at 925 ° C, and Gorilla glasses at Corning have softening temperatures of up to 850 ° C.

It is a good candidate to begin investigating its suitability as a substrate because the annealing temperature of the fused silica is about 1160 ° C. However, the sapphire films on fused silica show different behaviors compared to the quartz sapphire films annealed between 850 ° C and 1150 ° C, even though they are deposited under the same deposition conditions. The adhesion of the sapphire film on the fused silica is not as good as in quartz (due to a significant difference in the expansion coefficient); Localizing the splitting into thin pieces, and micro-sized cracking of the film on the molten silica substrate. However, using thinner membranes, these problems that could result in mild spawning were substantially mitigated. Figure 7 shows the transmittance of a 160 nm sapphire film on fused silica annealed at 1150 ° C for 2 hours. The transmittance of the sapphire thin film over the fused silica in the entire visible region between 400 nm and 700 nm is greater than 88.5% and up to 91.5% at 470 nm. The percentage of the total average light transmittance is about 90%, while that of the pure sapphire substrate is only 85% to 86%. In addition, the measured surface hardness is also held up to 8 in morascale.

Silicon having a melting point at about 1410 DEG C is an opaque substrate material. From the same deposition conditions, sapphire films on silicon still exhibit similar characteristics in Mohs hardness compared to quartz substrates, which are divided into two groups of temperature ranges. However, silicon is not a transparent substrate and therefore can not be used as a transparent cover glass or window application. Therefore, the sapphire film can only provide scratch-preventive purposes as a protective layer to protect the silicon surface from scratches (silicon has a MoS scale hardness of 7). Such a protective layer can potentially eliminate thick glass encapsulation. This improves light absorption and thus increases the efficiency of light harvesting. Other inorganic semiconductor based solar cells capable of withstanding high temperature processing can also deposit similar sapphire thin films thereon. From the embodiments of the present invention as described herein, those skilled in the art will appreciate that if the underlying substrate is capable of withstanding the annealing temperatures of the present invention for the applicable duration, the sapphire thin film as the scratch- It is envisaged that the present invention can be applied very well to deposit a sapphire thin film on other substrates so that it can function.

Sputtering  By deposition Annealed  Sapphire thin film

Sputtering  Sapphire Thin Film by Deposition

The steps for depositing a sapphire thin film on a given substrate by sputter deposition are given as follows:

1) Deposition of the sapphire thin film can be performed by sputtering deposition using aluminum or an aluminum oxide target.

2) The substrate is attached on a sample holder, which is about 95 mm away from the target. The sample holder is rotated at, for example, 10 RPM to achieve thickness uniformity when deposition is effected.

3) The base vacuum of the evaporation chamber is less than 3 × 10 ^-6 mbar and the coating pressure is about 3 × 10 ^-3 mbar.

4) The thickness of the film deposited on the substrate is between approximately 150 nm and 600 nm.

5) Film deposition at higher temperatures is possible from room temperature to 500 ° C.

The other Example Annealing  fair

After depositing a sapphire thin film on a substrate, they are annealed by a furnace from 500 ° C to 1300 ° C. The temperature rising rate is 5 占 폚 / min and the temperature lowering rate is 1 占 폚 / min. The time to hold at a particular thermal annealing temperature ranges between 30 minutes and 2 hours. Multi-step annealing at different temperatures is also used to increase hardness and also to reduce micro-cracks in the film. This is shown in Table 5.

Table 5: Surface hardness and XRD characterization peaks at different annealing temperatures for a sapphire film on quartz prepared by sputtering deposition.

Table 5 shows the change of the surface hardness of the sapphire thin film on quartz when the annealing temperature is changed from 500 占 폚 to 1300 占 폚. In fact, the initial value of the hardness of the sapphire thin film without annealing by sputtering deposition is slightly higher than that by e-beam deposition; It is about 6-6.5 mos. After performing the thermal annealing process, the performance of the film in terms of hardness is different from that of e-beam deposition. When the annealing temperature is in the range between 500 ° C and 850 ° C, the film hardness does not have any significant change. With respect to the range between 850 DEG C and 1150 DEG C, the thin film coated on the quartz easily peels off. However, in the range between 1150 ° C and 1300 ° C, the film forms a hard film, in which case its surface hardness has a thickness between 300 nm and 500 nm Has a moss of 8.5 to 8.8.

8A shows XRD results for 400 nm sapphire thin films on quartz annealed at 850, 1050 and 1200 for 2 hours. The resulting XRD peaks correspond to a mixture of delta (delta), theta, and alpha (alpha) structures of aluminum oxide. Unlike e-beam evaporation, the generation of the alpha phase of aluminum oxide in the XRD results for sputter deposition results in a more cured surface hardness, recording an average of 8.7 mos. 8B shows XRD results for a sapphire thin film having a thickness of 220 nm, 400 nm and 470 nm on quartz annealed at 1150 ° C for 2 hours. The occurrence of the alpha phase starts from about 300 nm, and when the thickness of the sapphire thin film increases to a maximum of 470 nm, the original composition of the structure is almost switched to the alpha phase. The surface hardness is the hardest under such conditions. However, when the thickness of the sapphire thin film is further increased, the film is peeled off.

The light transmission spectra of 220 nm, 400 nm and 470 nm sapphire thin films on quartz prepared by sputtering deposition annealing at 1100 캜 for 2 hours are shown in Fig. 9 and are compared with quartz substrates. With respect to the 220 nm sapphire thin film annealed in quartz, the optical performance is excellent and there is little scattering loss. The transmittance in the entire visible region between 400 nm and 700 nm is greater than 87% and up to 91.5% at 520 nm. The overall average transmittance is about 90.2%. The difference between the maximum intensity and the minimum intensity of the interference pattern is only about 4.5%.

However, when the thickness of the sapphire thin film is greater than 300 nm, the light transmittance intensity begins to fall particularly in the UV range, indicating that Rayleigh scattering is beginning to dominate. The strong wavelength dependence of Rayleigh scattering is applied to scattering particles with a particle size less than one tenth of the wavelength. This is due to the formation of alpha phase in a sapphire thin film with a sub-100 nm crystallite size. Therefore, the surface hardness becomes harder, but the transmittance becomes worse.

For the quartz annealed 400 nm sapphire and the annealed 470 nm sapphire thin film, the percentage of light transmittance in the entire visible region from 400 nm to 700 nm is 81% to 88% and 78% to 87%, respectively. Their overall average transmittance values are about 85.7% and 83.0%, respectively.

However, when the thickness of the sapphire thin film is larger than 500 nm, larger crystallites having microcracks accumulate, the microcracks are formed in the film, and some micro-sized pieces are peeled off the substrate.

Sputtering  Sapphire Thin Film on Fused Silica by Deposition

In addition to the quartz substrate, low-cost fused silica is a potential candidate for sapphire thin-film coated substrates because the annealing temperature of the fused silica is about 1160 ° C.

Table 6 shows the surface hardness of the sapphire thin film on fused silica when the annealing temperature varies from 750 캜 to 1150 캜. In fact, the initial value of the hardness of the sapphire thin film on the fused silica without annealing by sputter deposition is slightly lower than that for quartz at about 5.5 to 6 mos. In the range between 850 ° C and 1150 ° C, the hardness is less than 5 mos for all 150 nm to 600 nm sapphire films. However, at 1150 [deg.] C, the thin film can re-form a hard film, in which case its surface hardness has a mos of 8 to 8.5 for all sapphire films between 150 and 600 nm.

Table 6: Surface hardness and XRD characterization peaks at different annealing temperatures for sapphire films for fused silica prepared by sputtering deposition.

10 shows the XRD results for a 350 nm sapphire thin film on fused silica prepared by annealing and sputtering deposition at 750 ° C, 850 ° C, 1050 ° C and 1150 ° C for 2 hours. The XRD results show that the mixture of theta and alpha structures of aluminum oxide coexist on the fused silica substrate. Therefore, the sapphire film has a hard surface of 8 to 8.5 mos, whereas the fused silica substrate records only 5.3-6.5 mos.

11 shows the transmission spectrum of a 180 nm to 600 nm sapphire thin film on fused silica prepared by sputtering deposition annealing at 1150 ° C for 2 hours as compared to a fused silica substrate.

In the case of the annealed 180 nm sapphire thin film on fused silica and the 250 nm sapphire thin film, the optical performance is excellent and there is little scattering loss. The transmittance of the sapphire thin films in the entire visible region between 400 nm and 700 nm is between 88.9% and 93.1% and between 84.8% and 92.8%, respectively. Their overall average transmittance values are about 91.3% and 90.7%, respectively.

For annealed 340 nm sapphire thin films on fused silica and 600 nm sapphire thin films, the transmittance in the visible region between 400 nm and 700 nm is between 75% and 86% and between 64% and 80%, respectively. Their overall average transmittance is about 81.7% and 74.1%, respectively.

Therefore, the annealed sapphire thin film on fused silica at a thickness of between 150 nm and 300 nm at 1150 DEG C has good optical performance, has a transmittance of about 91%, and has a strong surface hardness of more than 8 mos.

Low temperature Annealing  fair

The current trend of 'toughened' screen materials is Corning's gorilla glass used in more than 1.5 billion devices. With a modest scale of hardness, the latest gorilla glass records only 6.5 to 6.8, which is below mineral quartz so that it is still easily scratched by sand. Therefore, there is another direction to deposit a harder thin film on the glass substrate. However, for most commonly used cover glasses, their maximum allowed annealing temperature is in the range between 600 ° C and 700 ° C. In this temperature range, the previous hardness of the annealed sapphire film can only reach 6 to 7 mos, which is close to that of the glass substrate itself. Therefore, a new technique is developed that uses an annealing temperature of less than 700 ° C to cause the annealed sapphire thin film to have a Moh hardness of greater than 7.

In another embodiment of the present invention, a monolayer or a plurality of higher hardness thin films of sapphire on a weaker hardness substrate with a maximum allowable annealing temperature below 850 DEG C, such as, for example, gorilla glass, tempered glass, soda lime glass, Layer can be deposited. Therefore, a harder scratch-resistant film may be coated on the glass. This is the fastest way to improve their surface hardness and is less costly.

In another embodiment of the present invention, it is shown that by applying a nano-layer of metal such as Ti and Ag, the polycrystalline sapphire thin film can be grown at lower temperatures. This catalyzed increase can be induced at significantly lower temperatures than when the nanometal catalyst was not used. This increase results from allowing crystallization to occur once there is sufficient kinetic energy to allow the deposited atoms to gather, and such an annealing temperature can start at 300 占 폚. Embodiments of the present invention in which the low temperature annealing starts from &lt; RTI ID = 0.0 &gt; 300 C &lt; / RTI &gt;

Table 7: Embodiments with a substrate / Ti catalyst / sapphire film structure at annealing temperatures of 300 ° C, 400 ° C and 500 ° C in the absence of annealing (room temperature, ie RT).

13A shows X-ray reflectance (XRR) measurement results for different samples with different annealing conditions for each embodiment in Table 7, and FIG. 13B shows the results of XRR measurements for different samples with different annealing conditions Lt; / RTI &gt; shows the optical transmission spectrum for the samples.

In one embodiment, a method of depositing a very thin &quot; discontinuous &quot; metal catalyst and a thicker sapphire film on a glass substrate has been developed. Through post-deposition treatments such as thermal annealing between 600 [deg.] C and 700 [deg.] C, a hardness of 7 to 7.5 mos higher than that of most glasses was achieved.

The nano-metal catalyst should have a thickness between 1 nm and 15 nm deposited by a deposition system such as e-beam evaporation or sputtering. This catalyst is not a continuous film as shown by SEM. The deposited metal may have a nano-dot (ND) shape with a diameter (of 5-20 nm). The metal includes titanium (Ti) and silver (Ag). The thicker sapphire film is in the range between 100 nm and 1000 nm.

In fact, the hardness value of the sapphire film by e-beam or sputtering deposition is not too high, only about 5.5 to 6 mos. However, after the thermal annealing process, the film thickness is significantly improved. Without a nano-metal catalyst, the film thickness is about 6 to 7 mos at an annealing temperature between 600 [deg.] C and 850 [deg.] C. After the addition of the nano-metal catalyst, the film hardness improved from 7 to 7.5 mos at an annealing temperature between 600 and 700 ° C and achieved a hardness of 8.5 to 9 mos at an annealing temperature between 701 ° C and 1300 ° C.

This is a much improved surface hardness on the glass substrate, especially below the glass softening temperature at such an annealing temperature. This means that the glass is not deformed during annealing. Therefore, the role of the metal catalyst is not only to increase adhesion between the sapphire thin film and the glass substrate, but also to cause hardening of the sapphire thin film. Table 8 shows the surface hardness of the sapphire films with and without nano-metal catalysts in the different annealing ranges provided by e-beam deposition.

Table 8: Surface hardness of sapphire films with and without nano-metal catalysts in different annealing ranges provided by e-beam deposition.

The summation points for a sapphire thin film deposited on a glass substrate by e-beam deposition are given by:

1) The base vacuum of the evaporation chamber is less than 5 × 10 ^-6 Torr, and the vacuum deposited when deposition occurs is kept below 1 × 10 ^-5 Torr.

2) The substrate is attached to the sample holder at a distance from the evaporation source, for example 450 nm. The sample holder is rotated at 1-2 RPM when deposition occurs.

3) Deposition of nanometals with higher melting points such as Ti, Cr, Ni, Si, Ag, Au, Ge, etc. uses deposition systems such as e-beam deposition and sputtering. The thickness of the metal catalyst mounted directly on the substrate is monitored by a QCM sensor at about 1 to 15 nm. The deposition rate of the nano-metal catalyst is about 0.1 A / s. The substrate during deposition has no external cooling or heating. Film morphology was measured by SEM top views and cross sections.

4) The deposition of the sapphire film uses e-beam deposition because it has a very high melting point at 2040 ° C. White pellets or colorless crystals of small size of pure aluminum oxide are used as e-beam deposition sources. The high melting point of the aluminum oxide also allows the annealing temperature to be lower than the melting point of the sapphire (e.g., 2040 ° C at atmospheric pressure).

5) The thickness of the sapphire thin film deposited on the substrate is between about 100 nm and 1000 nm. The deposition rate is about 1-5 A / s. The substrate being deposited is at room temperature, and the activation temperature is not essential. The film thickness can be measured with similar or better accuracy by ellipsometry or other suitable methods.

6) After the sapphire thin film is deposited on the substrate, the sapphire thin film is annealed in the furnace at a temperature between 500 ° C and 1300 ° C. The temperature ramp-up slope should be gradual, such as 5 ° C per minute, and the ramp-down slope should also be gradual, such as 1 to 5 ° C per minute. The annealing time is in the range of 30 minutes to 10 hours within the specified thermal annealing temperature range. Further, in order to increase the hardness of the thin film and also to reduce the microcracks of the thin film, it is also possible to anneal at a plurality of stages at different temperatures within the above-mentioned range.

The transmittance of the fused silica and the transmittance of the 250 nm annealed sapphire film with and without a 10 nm Ti catalyst on fused silica, annealed at 700 &lt; 0 &gt; C and 1150 &lt; 0 &gt; C for 2 hours are shown in Fig. For 700 ° C annealing results, the average transmittance percentage in the visible region of 400 nm to 700 nm is greater than 89.5%, the maximum is at 93.2% at 462 nm, and the fused silica substrate has an average transmittance of 93.5%.

Thin Film Transfer Process

Another embodiment of the present invention provides a method and apparatus by which a multilayer flexible metamaterial can be fabricated using flip chip transfer (FCT) technology. Such metamaterials include a more rigid thin film substrate transferred onto a soft flexible substrate. This technique differs from other similar technologies, such as a metal lift-off process, or nanometer printing techniques, in which nanostructures are fabricated directly on flexible substrates. It is a FCT technique without a solution using a double-side optical adhesive since the three-layer metamaterial nanostructure on the rigid substrate and the intermediate transfer layer can be transferred first on the adhesive. Another embodiment of the present invention is a fabrication method and apparatus that allows transfer of meta material from a rigid substrate such as glass, quartz, and metals onto a flexible substrate such as a plastic or polymer film. Thus, the flexible metamaterial can be fabricated regardless of the substrate originally used.

Device fabrication

A schematic fabrication process of the multi-layer metamaterial is shown in Fig. First, a multilayer plasmon or metamaterial device was fabricated on chromium (Cr) coated quartz using a conventional EBL process. A Cr layer with a thickness of 30 nm was used as the sacrificial layer. A gold / ITO (50 nm / 50 nm) thin film was then deposited on the Cr surface using thermal evaporation and RF sputtering methods, respectively. A ZEP520A (positive e-beam resist) thin film with a thickness of about 300 nm was then spun on top of the ITO / gold / Cr / quartz substrate and a two-dimensional hole array was obtained on the ZEP520A using the EBL process . In order to obtain a gold nanostructure (disk pattern), a 50 nm thick second gold thin film was coated on a resist having an e-beam pattern. Finally, by removing the resist residue, a two-dimensional gold disc-array nanostructure was formed. The area size of each meta-material pattern is 500 mu m x 500 mu m, the period of the disk array is 600 nm, and the disk diameter is 365 nm at the maximum.

Flip  Chip transfer FCT ) Technology

15 shows a process of transferring a flexible absorber metamaterial, in which a double-sided adhesive, optically transparent adhesive (having a thickness of 50 mu m; for example, a commercially available product manufactured by 3M Company) Branch). Thus a three layer metamaterial device is placed in close contact with the optical adhesive and is sandwiched between the rigid substrate and the optical adhesive. Note that the Cr thin film on the quartz was exposed to air for several hours after the RF sputtering process so that a thin native oxide film was present on the Cr surface. Therefore, the surface adhesion between Cr and gold is much weaker than that of gold / ITO / gold disc / optical adhesive bonding. This allows the 3-layer metamaterial nanostructure to be stripped from the Cr-coated quartz substrate. Once the metamaterial nanostructure is transported onto the PET substrate, it possesses sufficient flexibility to bend to various shapes. Finally, the metamaterial nanostructure was encapsulated by spin-coating a 300 nm thick PMMA layer on top of the device.

In another embodiment, the present invention provides a new NIR meta-material device that can be deformed into various shapes by bending the PET substrate.

16A shows a flexible absorber meta-material sandwiched between a transparent PET and a PMMA thin film. Various absorber metamaterial nanostructures having an area size of 500 mu m x 500 mu m were fabricated on a flexible substrate. In fact, using the flexible nature of the PET layer, the absorber metamaterial device can be matched in many shapes, such as cylindrical (Figure 16b). The minimum radius of the cylindrical substrate is about 3 mm and no obvious defects on the meta-material device can be observed after 10 repetitive bend tests.

optics Characterization  And optical characterization and simulation.

The three-layer metal / dielectric nanostructure discussed above is an absorber metamaterial device. The design of this device is such that the energy of the incident light is strongly localized in the ITO layer. The absorption effect of the NIR three layer metamaterial architecture can be interpreted as localized surface plasmon resonance or magnetic resonance. The absorption phenomenon discussed here differs from the suppression of the transmission effect in metal disk arrays where the incident light is strongly absorbed by the anomaly of extremely thin metal nanostructures. Fourier transform infrared spectroscopy (FTIR) was used to measure the reflection spectrum of the absorber metamaterial to characterize the optical properties of the gold disk / ITO / gold absorber metamaterial. By combining an infrared microscope with an FTIR spectrometer, the transmission spectrum and reflection spectrum from a micro-area nanoscopic device can be measured. In Fig. 17, the reflection spectrum (experimental line plot) from the air / meta material interface was measured with a sampling area of 100 mu m x 100 mu m. At an absorption peak with a wavelength of up to 1690 nm, the reflection efficiency is about 14%, i.e. the absorber meta-material acts at this wavelength. In the RCWA simulation (simulation line plot), E.D. Actual optical constants in Palik, Handbook of optical constants of solids, Academic Press, New York, 1985 are used; Which is incorporated herein by reference in its entirety. At the resonance wavelength, the experimental content and the calculated content agree well with each other.

The reflection spectrum of the flexible absorber meta-material is shown in Fig. 18a (0 [deg.] Line plot). In comparison with the FTIR results in Fig. 17, the absorption dip of the flexible meta-material was red shifted up to 1.81 [mu] m. This redshift is mainly due to the refractive index change of the surrounding medium (the refractive index of the optical adhesive and PET is about 1.44). 18C and 18D, a three-dimensional rigorously coupled wave analysis (RCWA) method is used to calculate the reflection and transmission spectra for the absorber metamaterial, and gold, ITO, Cr, SiO 2 , And experimentally identified parameters of the materials of PET were used. Resonance absorption at wavelengths up to 1.81 [mu] m can also be observed in the theoretical simulation. However, in the measured reflection spectrum, there are two resonance dips of approximately 1.2 mu m. In the RCWA calculation (Fig. 18c), a double dip is reproduced and is due to two localized resonance modes, because they are not very sensitive to the angle of incidence. For angle-dependent calculations, TE polarized light is used to match the experimental results (the electric field is perpendicular to the incident plane). When the incident light changes from 0 to 45 degrees, the reflection efficiency tends to increase because the light can not be localized efficiently at large incidence angles. However, the back reflection efficiency (FIG. 18A) in the experiment is obviously reduced. This is because this experimental setup (discussed in the next section) only allows the inventor to collect the backside reflectance signal (the incidence direction and the gathering direction are equal to each other), and the collecting efficiency is very low for large incidence angles to be. In Figure 18b, the transmissive spectrum of the flexible metamaterial was measured using the same FTIR setting, the main difference being that light was incident from the air / PMMA interface. A Fano-type transmission peak is observed at a wavelength of up to 1.85 占 퐉. At the resonance wavelength, the transmission efficiency from the test is higher than in the theoretical simulation (Fig. 18d). This may be due to defects in the planar film and the two-dimensional disk arrays of gold, which increases the efficiency of the leakage radiation and thus contributes to higher transmission efficiency in the measured results.

)은 메타물질 장치의 위치에서 구부러지는 기울기로부터 결정되었다. 도 18a로부터, 입사각이 0°로부터 45°까지 증가될 때, 배면 반사의 세기가 더 약해지고, 흡수 딥이 더 얕아지는 것이 관찰된다. 그렇지만, 그것은 가요성 흡수체 메타물질의 공명 흡수 파장이 광의 입사각에 민감하지 않은 것을 보여준다. 메타물질로부터 만들어진 장치는 매우 민감한 센서들로 만들어질 수 있다. 본 발명은 가요성 기판에 메타물질 장치들을 제작하는 새로운 기술을 제공한다. 가요성은 장치로 하여금 장치 구조를 변경시키는 구부림과 스트레칭(stretching)을 하는 것을 허용한다. 각 장치의 공명 주파수가 장치 구조의 함수이기 때문에, 공명 주파수는 기판의 구부림과 스트레칭에 의해 조정될 수 있다. 따라서, 본 발명의 다른 실시예는 물리적 수단이 그 재료의 구조를 변경하는 것을 허용하는 메타물질이고, 이는 그것의 공명 주파수의 변경을 가져온다. 물질 구성을 변경할 필요는 없다. 본 메타물질의 구현예는 전자파 흡수체로서 사용된 가요성 플라즈몬 또는 메타물질 나노구조 장치이다.As shown in Fig. 19, bending the PET substrate allows to measure the optical response of the absorber meta-material under different bending shapes. The shape of the curved PET substrate is controlled by adjusting the distance between the substrate ends A and B. The angle with respect to the resolved backside reflection in the absorber device was measured by varying the bending conditions. 19, incident light (90 DEG-

) Was determined from the slope of bending at the location of the meta-material device. From Fig. 18A, it is observed that when the incident angle is increased from 0 DEG to 45 DEG, the intensity of the back reflection becomes weaker and the absorption dip becomes shallower. However, it shows that the resonance absorption wavelength of the flexible absorber meta-material is not sensitive to the incident angle of light. Devices made from metamaterials can be made from very sensitive sensors. The present invention provides a new technique for fabricating metamaterial devices on flexible substrates. Flexibility allows the device to bend and stretch to alter the device structure. Since the resonant frequency of each device is a function of the device structure, the resonant frequency can be adjusted by bending and stretching the substrate. Thus, another embodiment of the present invention is a meta material that allows the physical means to modify the structure of the material, which results in a change in its resonant frequency. There is no need to change the material composition. An embodiment of the present meta-material is a flexible plasmonic or metamaterial nanostructure device used as an electromagnetic wave absorber.

In the above-described embodiments of the present invention, a flexible three-layer absorber meta-material device operating at the NIR wavelength has been reported. By using the FCT method, a three layer gold disk / ITO / gold absorber meta material was transferred from a quartz substrate to a transparent PET substrate using an optically transparent adhesive (e.g., a commercially available product made by 3M Company). In addition, the three-layer absorber meta-material was encapsulated by a PMMA thin film and an optical adhesive layer to form a flexible device. FTIR experiments have shown that the absorber metamaterial works well on both the quartz substrate and the highly flexible PET substrate. In addition, an angle-insensitive absorption effect and pano-type transmission resonance were observed in these flexible metamaterials.

In addition, the solution-free FCT technique described in this invention can also be used to transport other visible-NIR metal / dielectric multi-layer metamaterials onto a flexible substrate. Flexible metamaterials acting in the visibility-NIR framework show more advantages in manipulating light in three-dimensional space, especially when the metamaterial architecture is designed on curved surfaces. In another embodiment of the present invention, the FCT technique of the present invention can be employed to transfer a cured film to a soft, flexible substrate.

Flexibility  Transferring a thin film to a substrate Experiment details for Contents

The adopted method for transferring Al ₂ O ₃ films from a rigid substrate to a PET substrate is through transfer using a weakly adherent metal interlayer. This approach is based on U.S. Provisional Application No. 13 / 726,127, filed December 23, 2012, and U.S. Provisional Application No. 13 / 726,183, filed on December 23, 2012, both of which are incorporated herein by reference in their entirety U.S. Provisional Application No. 61 / 579,668, filed on March 23rd. One embodiment of the present invention is to use a transparent polyester tape that applies mechanical stress to separate the Al ₂ O ₃ thin film completely from the sacrificial metal layer. Then, the Al ₂ O ₃ thin film is transferred to the PET substrate, and the sacrificial metal layer can be etched by the acid.

First, a thin silver (Ag) film (i. E., A 30 to 100 nm thick) is deposited on a fused silica substrate and then deposited on top of Cr, Of) comes. Then another layer of metal such as a Ti film (3 to 10 nm thick) is deposited, which is for the annealing process. Then, an Al ₂ O ₃ thin film (for example, of 100 to 500 nm) is deposited on the metal layer. Annealing is then performed in a temperature range between 300 [deg.] C and 800 [deg.] C for each of the embodiments of the low temperature annealing process of the present invention as described hereinabove. A flexible transparent polyester tape having an optical transmittance higher than 95% is attached to the Al ₂ O ₃ film, and the cured Al ₂ O ₃ thin film is mechanically peeled again. The fabrication structure is schematically illustrated in Fig. Due to the different surface energies, the adhesion between Cr and Ag is weak and can therefore be easily overcome by applying stress. The applied stress consists of a pure open stress mode and a shear stress mode. These two modes ensure that there is a clear separation between Ag and Cr. Under the applied stress, the cured Al ₂ O ₃ thin film separates itself from the rigid substrate with the sacrificial Ag layer and the flexible transparent polyester tape as shown in FIG. Finally, the sacrificial layer is an Ag diluted HNO ₃ (1: 1) is etched by immersing the assembly, as shown in Figure 21 with an acid, such as. Because the tape and the Al ₂ O ₃ thin film are acid resistant, the etchant solution will only etch the sacrificial Ag layer faster. Al ₂ O ₃ is completely transferred to the PET substrate shown in FIG. 22 after the Ag thin film is completely etched.

result

Fig. 23 shows a sample prepared for transporting an Al ₂ O ₃ thin film. On the fused silica substrate, Cr having a thickness of typically 50 nm at a sputtering yield of about 5 nm / min was first sputtered onto the substrate. Then 50 nm of Ag was deposited on top of it by e-beam evaporation. Finally, about 200 nm thick Al ₂ O ₃ was deposited on the assembly by e-beam evaporation.

24 shows peeling of the Al ₂ O ₃ film from the molten silica substrate and Cr after applying mechanical stripping with a transparent tape. Al ₂ O ₃ is completely and smoothly separated from the rigid substrate with Ag film and tape without any cracks and bubbles. Al ₂ O ₃ is successfully transported to the flexible PET substrate after etching the sacrificial Ag layer with an acid.

In yet another embodiment of the present invention, the inventors have found that when depositing a layer of a higher hardness thin film (sapphire) on a substrate of weaker hardness such as, for example, soda lime glass (SLG), quartz and They were found through their attempts, experiments and investigations to carry out the work. This coupling is better than a bare sapphire substrate. Substantially higher hardness materials are less tough and the sapphire substrate is more difficult to scratch but fragile. Therefore, it is best to use a substrate of a weaker hardness with a thin film coating of a higher hardness. Substrates with relatively weaker hardness have small fragmentation potential, good mechanical performance and low cost. The function of scratch resistance is achieved by using a thin film coating of higher hardness.

In the present invention, a method of depositing a higher hardness alumina thin film on a quartz substrate is provided. The film thickness is in the range of 100 to 1000 nm. With subsequent post-deposition treatments such as thermal annealing at 25 캜 to 375 캜 at 25 캜 considered normal temperature, the present invention achieves a high hardness of greater than 14 GPa over uncoated soda lime glass having a typical hardness of 8 to 8.5 GPa do. This technique is called &quot; sapphire thin film coated substrate &quot;. Therefore, in view of hardness, and a sapphire substrate a thin film coating is comparable to that of pure sapphire screen, the weight of the other hand the density of quartz was only 2.65g / m ³ sapphire is compared to the pure sapphire substrate since the 3.98g / m ³ Which is roughly the same as that of a glass / quartz substrate roughly 66.6%. Since anyone can cut the substrate to a desired size and then deposit a sapphire thin film, the manufacturing cost and time are significantly reduced compared to the case of a pure sapphire substrate.

It has been found that alumina thin films coated on soda lime glass thermally annealed through sputtering and for 0.5 hour at 25 DEG C are harder than uncoated soda lime glass. The film hardness improved to over 14 GPa. Thus, the hardness of the annealed alumina film on the soda lime glass substrate is greater than the uncoated soda lime glass.

Further, according to the present invention, the annealing process of the alumina thin film on another substrate is performed at room temperature.

Deposition process

Deposited substrates, such as soda lime glass, quartz, glass.

Temperature of the substrate during deposition: from room temperature to 1000 &lt; 0 &gt; C.

Thin film thickness: 100 nm to 1000 nm.

Thermal annealing time: 30 minutes to 2 hours.

The deposition of the alumina thin film uses sputtering or e-beam.

The thickness of the film deposited on the substrate is about 100 to 1000 nm. The deposition rate is about 1 A / s. During deposition the substrate is not externally cooled or heated. The film thickness is measured by an ellipsometric method.

After deposition of the alumina thin film on the substrate, they are annealed at 25 占 폚. A certain thermal annealing temperature is maintained in the time range from 30 minutes to 2 hours.

The deposition substrate includes soda lime glass.

The result of nano-indentation of the alumina oxide thin film on the soda lime glass (SLG) substrate under different post annealing conditions is shown in Fig.

The addition of the present invention Example

In a further embodiment of the present invention, a layer of doped aluminum oxide (sapphire) thin film may act as an enhancement layer and be deposited on a sapphire thin film coated substrate. 26 shows the structure of a sample. The doping material may include chromium or chromium oxide; It is necessary to have a very different atomic size compared to aluminum, such as magnesium or magnesium oxide. Separate sizes of the two atoms form an interlocking mechanism in the membrane, which can result in a higher surface hardness of the membrane. This engagement mechanism is similar to chemically tempered glass using potassium to replace sodium in glass. The transmittance and hardness of the sample can be manipulated by the thickness of the enhancement layer, the doping ratio, and the doping material.

The intrinsic doping of aluminum oxide (sapphire) thin films can also serve as a unique identifier of a particular aluminum oxide (sapphire) thin film coating applied on a given substrate. Thus, another embodiment of the present invention provides a means for the manufacturer to track doped sapphire coatings fabricated by identifying the proportions and types of dopants used in the deposited sapphire thin film coating.

In one of the experiments described in the present invention, when the ratio of the enhancement layer is 1: 3 (aluminum oxide: chromium oxide) and is about 30 nm on top of a sapphire thin film coated substrate having a thickness of 200 nm by thermal annealing at 300 캜, The invention achieved a hardness of 17 GPa equivalent to 7.2 to 7.5 morascale in nanoindentation measurements (Figure 27).

In another experiment described, when the ratio of the enhancement layer was 1: 1 (aluminum oxide: magnesium oxide) and was about 30 nm on top of a sapphire thin film coated substrate having a thickness of 200 nm without annealing at room temperature, (Figure 28) of greater than 17 GPa, which is greater than 7.2 to 7.5. Figure 28 shows data for an enhancement layer that is a ratio of 1: 1 (aluminum oxide: magnesium oxide) deposited at room temperature onto different substrates, namely soda lime glass (SLG) and chemically enhanced aluminosilicate glass (ASS) . This data is shown in Table 9.

Table 9: Results of nanoindentation measurements on reinforcing layers in a ratio of 1: 1 (aluminum oxide: magnesium oxide) on SLG and ASS. (* Calculations were based on hardness of fused silica (9.25 GPa) and quartz (14.0 GPa), respectively.)

In Figure 29, the transmittance of a sample with different ratios of enhancement layers is shown. When the ratio of the strengthening layer is 1: 2 (aluminum oxide: chromium oxide), the transmittance in the visible light range is about 80%.

In Figure 30, a sample of an enhancement layer that is a ratio of 1: 1 (aluminum oxide: magnesium oxide) deposited at room temperature onto two different substrates, namely soda lime glass (SLG) and chemically enhanced aluminosilicate glass Is shown. When the ratio of the strengthening layer is 1: 1 (aluminum oxide: magnesium oxide), the transmittance exceeds 90% in the visible light range (400 nm to 700 nm). This data is shown in Table 10.

Table 10: Transmittance results for reinforcing layers in the ratio of 1: 1 (aluminum oxide: magnesium oxide) on SLG and ASS

The hardness value of the deposited sapphire film by e-beam or sputter deposition is about 12 to 13 GPa, which is about 5.5 to 6.5. After the thermal annealing process, the film hardness is significantly improved. However, the softening point of the glass is about 500 ° C, which means that the annealing temperature is not high enough to crystallize the sapphire. Alternatively, tempered glass, such as Corning's Gorilla glass, has a lower annealing temperature of 400 DEG C due to the enhancement layer. After the addition of the doped aluminum enhancement layer, the film hardness improved to 7.2 to 7.5 mos by annealing to 300 DEG C at a specific doping rate of the enhancement layer. This method greatly improves stress relief and surface hardness on tempered glass substrates by lowering the annealing temperature.

The procedure for depositing a doped aluminum oxide enhanced layer on a sapphire thin film coated substrate by sputter deposition is given by: &lt; RTI ID = 0.0 &gt;

1. Deposition of the sapphire film is described in U.S. Provisional Application No. 14 / 642,742, filed March 9, 2015, which claims priority from U.S. Provisional Application No. 62 / 049,364, filed September 12, "And follow the same procedure and experimental details.

2. The base vacuum of the chamber is higher than 5 × 10 ^-6 mbar and the deposition vacuum is maintained above 5 × 10 ^-3 mbar when deposition occurs.

3. The substrate is attached to the sample holder at a distance of, for example, 150 mm from the sputtering source. The sample holder is rotated at 10 RPM when deposition occurs.

4. Co-sputtering techniques are used to deposit a doped aluminum oxide layer on a sample. Two sputtering guns containing two different target materials operate simultaneously during coating. The doping ratio is controlled by the sputtering power. E-beam deposition with a similar arrangement is also possible.

5. The thickness of the doped aluminum oxide layer is 10 nm to 100 nm. The deposition rate is about 1 to 20 nm / min, depending on the type of target used, such as oxide or metal target. During the deposition, the substrate is at room temperature and the activation temperature is not essential. The film thickness is measured by ellipsometry or other suitable method with similar or better accuracy.

6. After depositing a doped aluminum oxide layer on a sapphire thin film coated substrate, they are annealed in the furnace from 50 캜 to 1300 캜. The temperature ramp-up slope should be gradual, such as 5 ° C per minute, and the ramp-down slope should also be gradual, such as 1 to 5 ° C per minute. The annealing time is in the range of 30 minutes to 10 hours within the specified thermal annealing temperature range. Further, in order to increase the hardness of the thin film and also to reduce the microcracks of the thin film, it is also possible to anneal at a plurality of stages at different temperatures within the above-mentioned range.

Other possible dopants used are beryllium, beryllium oxide, lithium, lithium oxide, sodium, sodium oxide, potassium, potassium oxide, calcium, calcium oxide, molybdenum, molybdenum oxide, tungsten and tungsten oxide. In fact, an embodiment of the present invention has spinel (MgAl ₂ O ₄ ) prepared in a doped aluminum oxide (sapphire) thin film coating on a softening substrate with a ratio of aluminum oxide: magnesium oxide of 1: 1. From the data in FIG. 31, a doped aluminum oxide (sapphire) thin film having a mixed oxide of MgO (aluminum oxide: magnesium oxide ratio of 1: 1) is deposited on the field silica (FS) using a physical vapor deposition process; Annealing at (S 1000A) and 1000 ° C (M 1000A) at (S 200A), 400 ° C, (S 400A), 600 ° C (S 600A), 800 ° C at different temperatures, , Different levels / concentrations of spinel are detected using XRD. Clearly, the most prominent peak of spinel is detected at 1000 ° C (M 1000A). Nevertheless, the XRD signal of the spinel is detected even at room temperature (RT) and the doped sapphire thin film with MgO is the hardest when there is no annealing, that is, at room temperature (RT). In addition, an XRD peak of alumina is detected at 1000 DEG C (M 1000A) and an XRD peak indicative of MgO is detected at all tested annealing temperature conditions other than 1000 DEG C (M 1000A). The physical deposition process used is either e-beam deposition or sputtering, where the deposition is free of external cooling or heating, and the entire process is performed at room temperature. It can also be seen from the data present in Table 11 that the aluminum oxide (sapphire) thin film layer serves to provide an adhesion force to bond to the substrate when the MgO mixed oxide is deposited at room temperature.

Table 11: Aluminum oxide (sapphire) with different thicknesses on different substrates: Thin film with 1: 1 MgO (mixed oxide).

The addition of the present invention Example

The sapphire thin film has high hardness mechanical properties, which means that it is very hard. Thus, when deposited on a soft or flexible substrate, the difference in mechanical properties between the sapphire and the substrate can cause the film to peel off when the film is too thick or cracked due to stresses between the substrate and the film. For example, the sapphire film starts to peel off from the PMMA or PET substrate when the film thickness exceeds 200 nm.

Also, the refractive index difference of the two materials means that light transmission through the layer can be trapped between the two materials. Thus, in another embodiment of the present invention, there is a buffer layer acting as a mechanical and optical intermediate layer. Mechanically, the buffer layer has a medium hardness between the soft substrate and the sapphire film, so that the high stress caused by the large hardness difference of the two materials can be relaxed. A thicker sapphire film can be grown with an optimum thickness range. A thicker sapphire film is preferred because scratch resistance requires a critical thickness to prevent piercing or penetration of the film. In addition, the buffer layer can reduce the interfacial stress, and thus the thin film has good adhesion.

Additional inventions

Embodiments of the present invention provide:

1. A buffer layer having a thickness of 10 to 100 nm is deposited on a flexible substrate such as PMMA and PET.

2. The deposition method is thermal deposition, sputtering or e-beam, and the substrate need not be heated. That is, the deposition is not externally cooled or heated.

3. The buffer layer material should have a higher mechanical hardness than the substrate and lower than the hardness of a typical sapphire film, and the typical value range is 1 to 5.5 MoS scale.

4. The refractive index of the buffer layer material should be higher than the refractive index of the substrate but lower than the refractive index of a typical sapphire film, and the typical value range is 1.45 to 1.65.

5. This buffer layer also improves the adhesion of sapphire because it reduces the stresses caused by the large differences in hardness.

6. An example of such material is silicon dioxide and SiO _2.

Using SiO ₂ as the buffer layer, the thickness of the sapphire layer can grow to 300 nm on PMMA before film exfoliation is observed. If no sapphire layer is Si0 _2, (hereinafter the "peeling" thick as the threshold thickness), the peeling is observed at 150nm or more in thickness. Thus, the buffer layer improves the mechanical stability of the sapphire film, thereby increasing the critical thickness by more than 100%.

The introduction of SiO ₂ as the buffer layer improved the overall optical transmittance of the coated substrate over the optical range by 2% or more. The transmittance enhancement is caused by the matching of the refractive index of the buffer layer so that light can pass from the substrate to the sapphire film with less loss. The enhancement is due to a reduction in the difference in refractive index values between the two material layers, e.g. the substrate and buffer layer, and the buffer layer and the sapphire film. The reduction in refractive index increases the Brewster angle, which defines the amount of light that can pass from one medium to another across the interface. The larger the Brewster angle, the more light can pass through the interface. Therefore, the introduction of the buffer layer between the substrate and the sapphire film increases the amount of transmitted light. This is shown in FIG.

As shown in Fig. 33, a hardness of 5 GPa or more is achieved when the total thickness is 200 nm or more (buffer layer and sapphire film) when measured using a nano-indenter. The hardness was significantly improved compared to the uncoated substrate. For example, the PMMA hardness is 0.3 GPa and the achieved hardness is 5.5 GPa; This means that the hardness increases by more than ten times. This confirms that hard and light transmission enhancement can be achieved by introducing a buffer layer between the soft substrate and the sapphire film.

The addition of the present invention Example

Additional embodiments in accordance with the invention as described in the specification are not intended to be limiting in scope by any one of the specific embodiments, but are provided for illustration only.

Without wishing to be bound by theory, the inventors have designed the composition of the AR layer for the purpose of matching the refractive indices of their underlying substrates, e.g., glass, chemically reinforced glass, plastic, etc., The experiment was found through experimentation and investigation. In the case of a device having a sapphire film for preventing scratching, the existing AR layer does not function properly because sapphire has a refractive index different from that of the lower substrate. Not only the amount of transmitted light is reduced, but also the transmission range is changed to impair the imaging or display color. Therefore, an AR integrated with a sapphire film having a top AR layer such as Al ₂ O ₃ serving as an anti-scratch layer will eliminate this problem. This AR such that the top layer is Al ₂ O ₃ which acts as a scratch-resistant layer comprises one of the alternative material in the AR layer to Al ₂ O _3.

A further embodiment of the invention provides the following features:

1. Al ₂ O ₃ is used to replace one of the AR film layers to achieve an antireflective function.

2. Two or more AR materials are generally Al ₂ O ₃ and TiO ₂ , and their refractive index difference should be as large as possible.

3. The top AR layer should be Al ₂ O ₃ acting as a scratch-resistant layer.

4. The number of layers ranges from 4 to 20 layers.

5. Deposition processes may use RF, DE sputtering, combinations thereof and / or e-beam deposition.

6. The annealing temperature is from 50 to 800 DEG C; The annealing further enhances scratch resistance hardness.

7. The annealing time is 0.5 to 2 hours.

8. The AR or scratch protection is not attenuated without annealing.

9. Doped sapphire can be an additional layer on the top sapphire layer to further improve its hardness.

10. The buffer layer may be added as a flexible / soft substrate before the integrated AR is deposited to improve adhesion.

11. Applicable to mobile phones, watches, camera lenses, binoculars, glasses, tablets and optical sensors.

Al ₂ O ₃ To  Achieve antireflection by replacing one of the AR membrane layers with

Fig. 34 shows an embodiment of an AR structure that uses Al ₂ O ₃ to replace the top AR film layer to achieve antireflection as well as scratch resistance. This structure is generally applicable to all transparent substrates by matching the refractive indices of alternately high and low substrate and upper Al ₂ O ₃ layers and other deposited AR layers.

Design of AR structure

n > 1.75 Outermost  layer

The composition of the AR layer is to match the refractive indices of the uppermost sapphire layer and the lower substrate. In one embodiment, the refractive index of a particular AR layer under the outermost sapphire layer should be higher than that of Al ₂ O ₃ in the range of 1.75 to 1.78 in the visible light region, as shown in Fig. TiO ₂ is a common AR material with a refractive index higher than Al ₂ O ₃ . Figs. 36 and 37 show another embodiment showing an AR structure having TiO ₂ on a glass substrate and its transmittance simulation, respectively.

In the AR structure, Outermost  The potential material, n > 1.75,

All materials with a refractive index higher than 1.75 in the visible light region are considered potential candidates of the second outermost layer in the AR structure. These materials _{YAG, AlAs, ZnSiAs 2, AgBr} , TlBr, C, B4C, SiC, AgCl, TlCl, BGO, PGO, CsI, KI, LiI, NaI, RbI, CaMoO 4, PbMoO 4, SrMoO 4, AlN, GaN , Si ₃ N ₄ , LiNbO ₃ , HfO ₂ , Nb ₂ O ₅ , Sc ₂ O ₃ , Y ₂ O ₃ , ZnO, ZrO ₂ , GaP, KTaO ₃ and BaTiO ₃ . Figure 38 and 39 shows another embodiment representing the AR structure and permeability simulation having a ZrO ₂ on a glass substrate, respectively. Figure 40 and 41 illustrates an embodiment showing the structure and the AR having a transmittance simulation HfO ₂ on a glass substrate, respectively. Figs. 42 and 43 show another embodiment showing an AR structure having GaN on a glass substrate and its transmittance simulation, respectively.

Different On the substrate  AR structure

In addition to depositing on glass and chemically reinforced glass substrates, AR structures can be applied to substrates of other materials such as sapphire, quartz, fused silica, plastics, and the like. Figs. 44, 45, 46, and 47 illustrate embodiments that illustrate an AR structure on a sapphire substrate, a specific AR transmittance simulation for sapphire, an AR structure on a PMMA substrate, and a specific AR transmittance simulation for a PMMA, respectively.

The first AR layer for the three-layer AR structure

The deposited first AR layer is Al ₂ O ₃ on a substrate of a non-sapphire material for an AR structure with a total of three layers. In the case of a sapphire substrate, the first AR layer is made of a material whose refractive index is lower than Al ₂ O ₃ , that is, 1.75. A common material with a low refractive index is MgF ₂ . Figs. 48 and 49 respectively show an embodiment showing a substrate of a material other than sapphire and a three-layer AR structure on a sapphire substrate. 50 and 51 illustrate a three-layer AR having TiO ₂ as a second outermost AR layer on a glass substrate, and MgF ₂ as a first AR layer and TiO ₂ as a second outermost AR layer on a sapphire substrate Transmittance simulation is shown.

Minimum thickness of AR layer

The thickness of each AR layer should be at least 10 nm. Membranes smaller than 10 nm may not be physically complete membranes. The matching of the index of refraction between the AR layer and the substrate is affected by the refractive index change in these layers. Further, the refractive index can not be accurately measured at a film thickness of less than 10 nm. The refractive index of the ultra thin film is greatly different from the refractive index of the bulk material. This difference is narrowed when the film is larger than 10 nm. Figure 52 shows the refractive indices of bilayer structures of different film thicknesses alternately formed by Al ₂ O ₃ and ZnO.

The maximum thickness of the AR layer

54 shows a three-layer AR having a thickness different from that of the first AR layer of Al ₂ O ₃ increasing from 400 to 1000 nm and having TiO ₂ as the second outermost layer on the glass substrate as shown in FIG. 53 Lt; RTI ID = 0.0 &gt; of &lt; / RTI &gt; By comparing the average transmittance in the visible light region of the glass substrate to the AR structure with the first Al ₂ O ₃ layer of 1000 nm, we have found one AR with lower transmittance that eliminates the AR effect. The maximum thickness of the AR layer can not exceed 800 nm.

1. < / RTI &gt; 1.75 as a low refractive index layer in the AR composition

In addition to MgF ₂ , all materials with a refractive index lower than 1.75 in the visible light region are considered potential candidates for the low refractive index layer in the AR structure. These materials include _{KCl, NaCl, RbCl, CaF 2} , KF, LaF 3, LiF, LiCaAlF 6, NaF, RbF, SrF 2, ThF 4, YLiF 4, GeO 2, SiO 2, KH 2 PO 4 and CS ₂ do. 55 and 56 show a three layer AR structure having SiO ₂ as a first AR layer on a sapphire substrate and its transmittance simulation, respectively. 57 and 58 show another embodiment showing a three layer AR structure having LiF as a first AR layer on a sapphire substrate and its transmittance simulation, respectively. 59 and 60 show an embodiment showing a three layer AR structure with KCl as the first AR layer and a transmittance simulation thereof, respectively, on a sapphire substrate.

AR of more than 3 AR layers in total Having a composition Example

Figs. 61 and 62 show an embodiment showing a five-layer AR structure on a glass substrate and a six-layer AR structure on a sapphire substrate, respectively. SiO ₂ is regarded as a low-index AR layer TiO ₂ is employed as a second outermost layer for the two structures. Their transmittance simulation spectra are shown in Figs. 63 and 64, respectively.

Generally, the AR layer consists of alternating Al ₂ O ₃ films and low refractive index layer deposition on the substrate. In the case of a substrate of non-sapphire material, the Al ₂ O ₃ AR layer is deposited first followed by a low refractive index layer, whereas in the case of a sapphire substrate. That is, the Al ₂ O ₃ AR layer is deposited after the low refractive index layer. This order can be extended to a larger number of layers. The high refractive index AR layer as the second outermost layer is coated on top of the pair of Al ₂ O ₃ and low refractive index layers. Finally, the top Al ₂ O ₃ AR layer is fabricated.

65 and 66 illustrate a general embodiment of the present invention having a substrate of a material other than sapphire and an AR composition on a sapphire substrate, respectively.

Test results Simulated  Transmittance

67 shows an embodiment having an AR structure of [glass / Al ₂ O ₃ (160 nm) / LiF (75 nm) / Al ₂ O ₃ (80 nm) / TiO ₂ (96 nm) / Al ₂ O ₃ do. AR layer coating samples produced by electron beam deposition and sputtering, simulation of specific composition, and transmittance of bare glass substrate. In Figure 67, the experimental transmittance strongly agrees with the simulated. The change in the average transmittance in the visible light region is less than 1% when the experimental results are compared with the simulation data. With the AR structure, 91.7% to 94% more light is transmitted through the substrate in the visible light region. It has also been demonstrated that the AR structure can be fabricated by other physical vapor deposition (PVD) methods such as electron beam deposition and sputtering.

Current embodiments of the present invention may also be applied to flexible flexible substrates such as polymers, plastics, paper and textiles.

Modifications and variations that may be apparent to one of ordinary skill in the art are deemed to be within the scope of the present invention.

Another further embodiment of the present invention provides:

Diamond Award  Carbon (diamond-like carbon, DLC ) Layer AR composition

This AR structure can be combined with a diamond-like carbon (DLC) layer to have an optically reduced reflectance. 68 shows a transmittance simulation spectrum of an AR structure on a sapphire substrate having a diamond-like carbon layer in its composition.

The present invention relates to the composition of an AR layer intended to match the refractive index of a lower substrate such as, for example, glass, chemically tempered glass, plastic, etc., in order to maximize light transmitted through the AR layer. In the case of a device having a sapphire film for anti-scratching, since the sapphire has a refractive index different from the refractive index of the lower substrate, the conventional AR layer does not function properly; Not only the amount of transmitted light is reduced, but also the transmission range is changed to impair imaging and / or display color. Therefore, an AR integrated with a sapphire film having a top AR layer such as Al ₂ O ₃ serving as an anti-scratch layer will eliminate this problem. This AR such that the top layer is Al ₂ O ₃ which acts as a scratch-resistant layer comprises one of the alternative material in the AR layer to Al ₂ O _3.

If desired, the different functions discussed herein may be performed in different orders and / or concurrently. Also, if desired, one or more of the foregoing functions may be optional or combined.

Throughout this specification, unless the context requires otherwise, the word " comprise " and its conjugations, such as " comprises " or " comprising " include the explicitly stated group of integers or integers , But does not exclude any other integer or group of integers. It is also noted that in the present disclosure, and particularly in the claims and / or paragraphs, terms such as "comprises", "comprised", "comprising", and the like may have the meaning of having attributes in US patent law, May mean "includes," "included," "including," and the like terms such as "consisting essentially of" and "consisting essentially of" For example, they exclude elements that are not explicitly listed, but exclude elements found in the prior art or that affect the basic or novel features of the invention.

In addition, throughout this specification and the claims, unless the context requires otherwise, the word " include " and uses such as "includes" or "including" , But does not exclude any other integer or group of integers.

Other definitions of selected terms used herein may be found within the Detailed Description of the invention and apply throughout the specification. Unless defined otherwise, all other technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

While the foregoing invention has been described in terms of various embodiments and examples, it is understood that other embodiments are within the scope of the invention as expressed in the following claims and their equivalents. In addition, the specific examples above are to be construed as merely illustrative, and not as limiting the remainder of the disclosure in any way. Without further elaboration, it is believed that one skilled in the art can, based on the description herein, utilize the present invention to its fullest extent. All publications listed in this specification are incorporated herein by reference in their entirety.

The authentication or identification of any reference in this section or any other section of this document shall not be construed as an admission that such reference is valid as prior art to this application.

Claims (21)

An antireflective coating on a substrate comprising a layered structure,
An uppermost antireflective material layer comprising sapphire or Al ₂ O ₃ on top of at least one antireflective material layer, the at least one antireflective material layer having a higher index of refraction than the top antireflective material layer;
One or more anti-reflection material layers, the intermediate anti-reflective material layer directly under the top anti-reflective material layer is a second anti-reflective material layer, and has a higher refraction index than the refractive index of the top anti-reflective material layer; And
And a lowermost anti-reflective material layer under the one or more anti-reflective material layers, wherein the lowermost anti-reflective material layer is deposited on top of the substrate,
Wherein the top anti-glare material layer, the at least one anti-glare material layer, and the bottom anti-glare material layer have a high and low refractive index, alternating with respect to each other,
Anti-reflective coating on substrate. The method according to claim 1,
Wherein the second anti-reflective material layer has a refractive index in the range of 1.75 to 1.78 in the visible light region,
Anti-reflective coating on substrate. 3. The method of claim 2,
Wherein the _second anti-reflective material layer comprises TiO ₂ .
Anti-reflective coating on substrate. The method according to claim 1,
Wherein the second anti-reflective material layer has a refractive index greater than 1.75 in the visible light region,
Anti-reflective coating on substrate. 5. The method of claim 4,
The second anti-reflective material layer is _{YAG, AlAs, ZnSiAs 2, AgBr} , TlBr, C, B 4 C, SiC, AgCl, TlCl, BGO, PGO, CsI, KI, LiI, NaI, RbI, CaMoO 4, PbMoO 4 , the SrMoO _4, AlN, GaN, Si ₃ N _4, LiNbO _3, HfO _2, Nb ₂ O _5, Sc ₂ O _3, Y ₂ O _3, ZnO, ZrO _2, GaP, KTaO _3, and BaTiO one or more of the _three Including,
Anti-reflective coating on substrate. The method according to claim 1,
Wherein the substrate comprises at least one of glass, sapphire, quartz, fused silica, plastic and PMMA.
Anti-reflective coating on substrate. The method according to claim 1,
The bottom anti-reflective material layer of the layered structure deposited on top of said substrate is Al ₂ O _3,
The substrate is not sapphire or Al ₂ O ₃ ,
Anti-reflective coating on substrate. 8. The method of claim 7,
Wherein the layered structure comprises a three-layer structure of antireflective material,
Anti-reflective coating on substrate. 9. The method of claim 8,
Wherein the _second anti-reflective material layer comprises TiO ₂ .
Anti-reflective coating on substrate. The method according to claim 1,
Wherein the lowermost anti-reflective material layer deposited on top of the substrate is not Al ₂ O ₃ ,
Wherein the substrate is a sapphire or Al ₂ O ₃ ,
Anti-reflective coating on substrate. 11. The method of claim 10,
Wherein the layered structure comprises a three-layer structure of antireflective material,
Anti-reflective coating on substrate. 12. The method of claim 11,
Wherein the _second anti-reflective material layer comprises TiO ₂ .
Anti-reflective coating on substrate. 12. The method of claim 11,
Wherein the lowermost anti-reflective material layer deposited on top of the substrate comprises MgF ₂ or SiO ₂ .
Anti-reflective coating on substrate. The method according to claim 1,
The thickness of each anti-reflection material layer is at least 10 nm,
Anti-reflective coating on substrate. The method according to claim 1,
The thickness of each anti-reflection material layer is 800 nm or less,
Anti-reflective coating on substrate. The method according to claim 1,
Each of the anti-reflective material layer having a low refractive index is _{MgF 2, KCl, NaCl, RbCl} , CaF 2, KF, LaF 3, LiF, LiCaAlF 6, NaF, RbF, SrF 2, ThF 4, YLiF 4, GeO 2, SiO ₂ , KH ₂ PO _4, and CS ₂ .
Anti-reflective coating on substrate. The method according to claim 1,
Wherein the top anti-reflective material layer comprises sapphire or Al ₂ O ₃ ,
Wherein the second anti-reflective material layer comprises an anti-reflective material having a refractive index higher than that of the top anti-reflective material layer,
Wherein the lowermost anti-reflective material layer comprises sapphire or Al ₂ O ₃ if the substrate is not sapphire or Al ₂ O ₃ ,
Wherein the anti-reflection material layer on the top of the lowermost anti-reflection material layer comprises an anti-reflection material having a refractive index higher than that of the lowermost anti-
Anti-reflective coating on substrate. The method according to claim 1,
Wherein the top anti-reflective material layer comprises sapphire or Al ₂ O ₃ ,
Wherein the second anti-reflective material layer comprises an anti-reflective material having a refractive index higher than that of the top anti-reflective material layer,
Wherein the lowermost anti-reflective material layer comprises an anti-reflective material having a refractive index lower than the refractive index of the anti-reflective material layer on top of the lowermost anti-reflective material layer when the substrate is sapphire or Al ₂ O ₃ ,
Wherein the anti-reflection material layer on the top of the lowermost anti-reflective material layer comprises an anti-reflection material having a refractive index lower than the refractive index of the substrate.
Anti-reflective coating on substrate. 19. The method of claim 18,
The anti-reflection material layer on the top of the lowermost anti-reflective material layer may comprise sapphire or Al ₂ O ₃ ,
Anti-reflective coating on substrate. The method according to claim 1,
The layered structure of the antireflective material layer is formed using a physical vapor deposition (PVD) method comprising at least one of electron beam deposition and sputtering.
Anti-reflective coating on substrate. An antireflective coating on a substrate comprising a layered structure,
An uppermost anti-reflective material layer comprising sapphire or Al ₂ O ₃ on top of the lowermost anti-reflective material layer; And
And a lowermost anti-reflective material layer deposited on top of the substrate,
Wherein the uppermost anti-reflective material layer and the lowermost anti-reflective material layer have a high and low refractive index, alternately with respect to each other,
Reflective ring coating on substrate.

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