EP4323815A1 - Optische materialien und verfahren mit geringem verlust - Google Patents
Optische materialien und verfahren mit geringem verlustInfo
- Publication number
- EP4323815A1 EP4323815A1 EP22721224.8A EP22721224A EP4323815A1 EP 4323815 A1 EP4323815 A1 EP 4323815A1 EP 22721224 A EP22721224 A EP 22721224A EP 4323815 A1 EP4323815 A1 EP 4323815A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- overcoat layer
- layer
- grating
- light
- relief grating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 191
- 239000000463 material Substances 0.000 title claims abstract description 158
- 230000003287 optical effect Effects 0.000 title claims abstract description 81
- 230000008569 process Effects 0.000 title claims description 134
- 239000002105 nanoparticle Substances 0.000 claims abstract description 173
- 239000000758 substrate Substances 0.000 claims abstract description 73
- 229910044991 metal oxide Inorganic materials 0.000 claims abstract description 67
- 150000004706 metal oxides Chemical class 0.000 claims abstract description 67
- 230000003667 anti-reflective effect Effects 0.000 claims abstract description 10
- 239000010410 layer Substances 0.000 claims description 498
- 239000011347 resin Substances 0.000 claims description 140
- 229920005989 resin Polymers 0.000 claims description 140
- 239000011368 organic material Substances 0.000 claims description 66
- 229910010272 inorganic material Inorganic materials 0.000 claims description 45
- 239000011147 inorganic material Substances 0.000 claims description 45
- 239000002904 solvent Substances 0.000 claims description 41
- 239000006117 anti-reflective coating Substances 0.000 claims description 32
- 238000004151 rapid thermal annealing Methods 0.000 claims description 31
- 238000000151 deposition Methods 0.000 claims description 30
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 27
- 238000000231 atomic layer deposition Methods 0.000 claims description 27
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 26
- -1 Z1O2 Chemical compound 0.000 claims description 25
- 238000010336 energy treatment Methods 0.000 claims description 24
- CUDYYMUUJHLCGZ-UHFFFAOYSA-N 2-(2-methoxypropoxy)propan-1-ol Chemical compound COC(C)COC(C)CO CUDYYMUUJHLCGZ-UHFFFAOYSA-N 0.000 claims description 23
- LLHKCFNBLRBOGN-UHFFFAOYSA-N propylene glycol methyl ether acetate Chemical compound COCC(C)OC(C)=O LLHKCFNBLRBOGN-UHFFFAOYSA-N 0.000 claims description 23
- 238000004528 spin coating Methods 0.000 claims description 21
- 238000000576 coating method Methods 0.000 claims description 20
- KPUWHANPEXNPJT-UHFFFAOYSA-N disiloxane Chemical class [SiH3]O[SiH3] KPUWHANPEXNPJT-UHFFFAOYSA-N 0.000 claims description 17
- 239000013110 organic ligand Substances 0.000 claims description 17
- 239000002243 precursor Substances 0.000 claims description 17
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 16
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical compound [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 claims description 15
- 239000004925 Acrylic resin Substances 0.000 claims description 15
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 15
- 238000010521 absorption reaction Methods 0.000 claims description 15
- 229910052799 carbon Inorganic materials 0.000 claims description 15
- 239000004593 Epoxy Substances 0.000 claims description 12
- 238000005240 physical vapour deposition Methods 0.000 claims description 12
- DWCMDRNGBIZOQL-UHFFFAOYSA-N dimethylazanide;zirconium(4+) Chemical compound [Zr+4].C[N-]C.C[N-]C.C[N-]C.C[N-]C DWCMDRNGBIZOQL-UHFFFAOYSA-N 0.000 claims description 11
- JLTRXTDYQLMHGR-UHFFFAOYSA-N trimethylaluminium Chemical compound C[Al](C)C JLTRXTDYQLMHGR-UHFFFAOYSA-N 0.000 claims description 11
- 229910003087 TiOx Inorganic materials 0.000 claims description 10
- 229910052681 coesite Inorganic materials 0.000 claims description 10
- 229910052906 cristobalite Inorganic materials 0.000 claims description 10
- 229910052682 stishovite Inorganic materials 0.000 claims description 10
- MNWRORMXBIWXCI-UHFFFAOYSA-N tetrakis(dimethylamido)titanium Chemical compound CN(C)[Ti](N(C)C)(N(C)C)N(C)C MNWRORMXBIWXCI-UHFFFAOYSA-N 0.000 claims description 10
- HLLICFJUWSZHRJ-UHFFFAOYSA-N tioxidazole Chemical compound CCCOC1=CC=C2N=C(NC(=O)OC)SC2=C1 HLLICFJUWSZHRJ-UHFFFAOYSA-N 0.000 claims description 10
- 229910052905 tridymite Inorganic materials 0.000 claims description 10
- 230000015572 biosynthetic process Effects 0.000 claims description 9
- 238000003786 synthesis reaction Methods 0.000 claims description 9
- 238000000137 annealing Methods 0.000 claims description 8
- 230000005670 electromagnetic radiation Effects 0.000 claims description 6
- LCZVSXRMYJUNFX-UHFFFAOYSA-N 2-[2-(2-hydroxypropoxy)propoxy]propan-1-ol Chemical compound CC(O)COC(C)COC(C)CO LCZVSXRMYJUNFX-UHFFFAOYSA-N 0.000 claims description 4
- 229910010165 TiCu Inorganic materials 0.000 claims description 4
- 238000005229 chemical vapour deposition Methods 0.000 claims description 4
- RTZKZFJDLAIYFH-UHFFFAOYSA-N ether Substances CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 claims description 4
- 239000003960 organic solvent Substances 0.000 claims description 4
- 238000001764 infiltration Methods 0.000 claims description 3
- 230000008595 infiltration Effects 0.000 claims description 3
- ZKATWMILCYLAPD-UHFFFAOYSA-N niobium pentoxide Chemical compound O=[Nb](=O)O[Nb](=O)=O ZKATWMILCYLAPD-UHFFFAOYSA-N 0.000 claims description 3
- PBCFLUZVCVVTBY-UHFFFAOYSA-N tantalum pentoxide Inorganic materials O=[Ta](=O)O[Ta](=O)=O PBCFLUZVCVVTBY-UHFFFAOYSA-N 0.000 claims description 3
- 239000012702 metal oxide precursor Substances 0.000 claims description 2
- 239000000377 silicon dioxide Substances 0.000 claims description 2
- 238000001127 nanoimprint lithography Methods 0.000 description 30
- 239000000203 mixture Substances 0.000 description 28
- 230000009471 action Effects 0.000 description 25
- 238000001723 curing Methods 0.000 description 25
- 238000003384 imaging method Methods 0.000 description 23
- 150000003254 radicals Chemical class 0.000 description 23
- 238000009472 formulation Methods 0.000 description 18
- 230000032798 delamination Effects 0.000 description 17
- 230000001699 photocatalysis Effects 0.000 description 17
- 230000003190 augmentative effect Effects 0.000 description 15
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 14
- 229910052710 silicon Inorganic materials 0.000 description 14
- 239000010703 silicon Substances 0.000 description 14
- 239000010936 titanium Substances 0.000 description 14
- 238000004891 communication Methods 0.000 description 13
- 230000006870 function Effects 0.000 description 13
- 239000011148 porous material Substances 0.000 description 13
- 230000008878 coupling Effects 0.000 description 12
- 238000010168 coupling process Methods 0.000 description 12
- 238000005859 coupling reaction Methods 0.000 description 12
- 230000033001 locomotion Effects 0.000 description 12
- 239000004205 dimethyl polysiloxane Substances 0.000 description 11
- 239000011521 glass Substances 0.000 description 11
- 229920000435 poly(dimethylsiloxane) Polymers 0.000 description 11
- 239000011248 coating agent Substances 0.000 description 10
- 239000003446 ligand Substances 0.000 description 10
- 238000005259 measurement Methods 0.000 description 10
- 238000005530 etching Methods 0.000 description 9
- 229920000840 ethylene tetrafluoroethylene copolymer Polymers 0.000 description 9
- 239000010408 film Substances 0.000 description 9
- 239000011888 foil Substances 0.000 description 9
- 239000010702 perfluoropolyether Substances 0.000 description 9
- 238000003860 storage Methods 0.000 description 9
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 9
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 8
- 238000004833 X-ray photoelectron spectroscopy Methods 0.000 description 8
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 8
- 238000003475 lamination Methods 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 8
- 229910052760 oxygen Inorganic materials 0.000 description 8
- 239000001301 oxygen Substances 0.000 description 8
- 238000000059 patterning Methods 0.000 description 8
- 210000001747 pupil Anatomy 0.000 description 8
- 229910052719 titanium Inorganic materials 0.000 description 8
- 230000000295 complement effect Effects 0.000 description 7
- 238000010586 diagram Methods 0.000 description 7
- 238000007641 inkjet printing Methods 0.000 description 7
- 229920000620 organic polymer Polymers 0.000 description 7
- 229920000642 polymer Polymers 0.000 description 7
- 239000002861 polymer material Substances 0.000 description 7
- 229920002379 silicone rubber Polymers 0.000 description 7
- 238000005516 engineering process Methods 0.000 description 6
- 229920002313 fluoropolymer Polymers 0.000 description 6
- 239000000178 monomer Substances 0.000 description 6
- 238000000465 moulding Methods 0.000 description 6
- 229920000058 polyacrylate Polymers 0.000 description 6
- 230000004075 alteration Effects 0.000 description 5
- 238000003491 array Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 210000003128 head Anatomy 0.000 description 5
- 230000003993 interaction Effects 0.000 description 5
- 230000004044 response Effects 0.000 description 5
- 229920001621 AMOLED Polymers 0.000 description 4
- 229910003070 TaOx Inorganic materials 0.000 description 4
- 229910026551 ZrC Inorganic materials 0.000 description 4
- 229910003134 ZrOx Inorganic materials 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 4
- 238000000429 assembly Methods 0.000 description 4
- 230000000712 assembly Effects 0.000 description 4
- 230000001427 coherent effect Effects 0.000 description 4
- 238000004590 computer program Methods 0.000 description 4
- 238000004132 cross linking Methods 0.000 description 4
- 238000010884 ion-beam technique Methods 0.000 description 4
- 230000031700 light absorption Effects 0.000 description 4
- 239000002086 nanomaterial Substances 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- 238000009281 ultraviolet germicidal irradiation Methods 0.000 description 4
- 229910005540 GaP Inorganic materials 0.000 description 3
- 230000001133 acceleration Effects 0.000 description 3
- 238000009835 boiling Methods 0.000 description 3
- 230000015556 catabolic process Effects 0.000 description 3
- 238000005034 decoration Methods 0.000 description 3
- 238000006731 degradation reaction Methods 0.000 description 3
- QHSJIZLJUFMIFP-UHFFFAOYSA-N ethene;1,1,2,2-tetrafluoroethene Chemical group C=C.FC(F)=C(F)F QHSJIZLJUFMIFP-UHFFFAOYSA-N 0.000 description 3
- 238000010030 laminating Methods 0.000 description 3
- 239000004973 liquid crystal related substance Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 229920003023 plastic Polymers 0.000 description 3
- 239000004033 plastic Substances 0.000 description 3
- 238000007639 printing Methods 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 230000001902 propagating effect Effects 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- 238000001429 visible spectrum Methods 0.000 description 3
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 2
- WAEVWDZKMBQDEJ-UHFFFAOYSA-N 2-[2-(2-methoxypropoxy)propoxy]propan-1-ol Chemical compound COC(C)COC(C)COC(C)CO WAEVWDZKMBQDEJ-UHFFFAOYSA-N 0.000 description 2
- 229910017107 AlOx Inorganic materials 0.000 description 2
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 2
- 101150063042 NR0B1 gene Proteins 0.000 description 2
- OUUQCZGPVNCOIJ-UHFFFAOYSA-M Superoxide Chemical compound [O-][O] OUUQCZGPVNCOIJ-UHFFFAOYSA-M 0.000 description 2
- 238000003848 UV Light-Curing Methods 0.000 description 2
- YHWCPXVTRSHPNY-UHFFFAOYSA-N butan-1-olate;titanium(4+) Chemical compound [Ti+4].CCCC[O-].CCCC[O-].CCCC[O-].CCCC[O-] YHWCPXVTRSHPNY-UHFFFAOYSA-N 0.000 description 2
- CQEYYJKEWSMYFG-UHFFFAOYSA-N butyl acrylate Chemical compound CCCCOC(=O)C=C CQEYYJKEWSMYFG-UHFFFAOYSA-N 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 239000003989 dielectric material Substances 0.000 description 2
- 238000001312 dry etching Methods 0.000 description 2
- 230000004424 eye movement Effects 0.000 description 2
- 239000003574 free electron Substances 0.000 description 2
- 125000000524 functional group Chemical group 0.000 description 2
- HZXMRANICFIONG-UHFFFAOYSA-N gallium phosphide Chemical compound [Ga]#P HZXMRANICFIONG-UHFFFAOYSA-N 0.000 description 2
- 230000014509 gene expression Effects 0.000 description 2
- 238000001802 infusion Methods 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000007726 management method Methods 0.000 description 2
- 238000005459 micromachining Methods 0.000 description 2
- QGLKJKCYBOYXKC-UHFFFAOYSA-N nonaoxidotritungsten Chemical compound O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1 QGLKJKCYBOYXKC-UHFFFAOYSA-N 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 description 2
- 230000008447 perception Effects 0.000 description 2
- 230000001443 photoexcitation Effects 0.000 description 2
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 2
- 239000004926 polymethyl methacrylate Substances 0.000 description 2
- 239000010453 quartz Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000006722 reduction reaction Methods 0.000 description 2
- 230000001953 sensory effect Effects 0.000 description 2
- 239000012703 sol-gel precursor Substances 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 230000003746 surface roughness Effects 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- 229910001930 tungsten oxide Inorganic materials 0.000 description 2
- 230000000007 visual effect Effects 0.000 description 2
- 238000001039 wet etching Methods 0.000 description 2
- 229910001928 zirconium oxide Inorganic materials 0.000 description 2
- 241000226585 Antennaria plantaginifolia Species 0.000 description 1
- 229910002601 GaN Inorganic materials 0.000 description 1
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 description 1
- JMASRVWKEDWRBT-UHFFFAOYSA-N Gallium nitride Chemical compound [Ga]#N JMASRVWKEDWRBT-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910020286 SiOxNy Inorganic materials 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 238000000560 X-ray reflectometry Methods 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 230000032900 absorption of visible light Effects 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 238000004887 air purification Methods 0.000 description 1
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical group [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 1
- 229910003481 amorphous carbon Inorganic materials 0.000 description 1
- 229910021417 amorphous silicon Inorganic materials 0.000 description 1
- 201000009310 astigmatism Diseases 0.000 description 1
- 230000006399 behavior Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 230000010267 cellular communication Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000013500 data storage Methods 0.000 description 1
- 230000006837 decompression Effects 0.000 description 1
- 238000012217 deletion Methods 0.000 description 1
- 230000037430 deletion Effects 0.000 description 1
- 229910003460 diamond Inorganic materials 0.000 description 1
- 239000010432 diamond Substances 0.000 description 1
- 125000002147 dimethylamino group Chemical group [H]C([H])([H])N(*)C([H])([H])[H] 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 229910052733 gallium Inorganic materials 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910000449 hafnium oxide Inorganic materials 0.000 description 1
- WIHZLLGSGQNAGK-UHFFFAOYSA-N hafnium(4+);oxygen(2-) Chemical compound [O-2].[O-2].[Hf+4] WIHZLLGSGQNAGK-UHFFFAOYSA-N 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 230000004886 head movement Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229920002100 high-refractive-index polymer Polymers 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 238000002329 infrared spectrum Methods 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000001459 lithography Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000003550 marker Substances 0.000 description 1
- 229910003465 moissanite Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 125000004430 oxygen atom Chemical group O* 0.000 description 1
- BPUBBGLMJRNUCC-UHFFFAOYSA-N oxygen(2-);tantalum(5+) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ta+5].[Ta+5] BPUBBGLMJRNUCC-UHFFFAOYSA-N 0.000 description 1
- NFHFRUOZVGFOOS-UHFFFAOYSA-N palladium;triphenylphosphane Chemical compound [Pd].C1=CC=CC=C1P(C=1C=CC=CC=1)C1=CC=CC=C1.C1=CC=CC=C1P(C=1C=CC=CC=1)C1=CC=CC=C1.C1=CC=CC=C1P(C=1C=CC=CC=1)C1=CC=CC=C1.C1=CC=CC=C1P(C=1C=CC=CC=1)C1=CC=CC=C1 NFHFRUOZVGFOOS-UHFFFAOYSA-N 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 239000011941 photocatalyst Substances 0.000 description 1
- 238000001020 plasma etching Methods 0.000 description 1
- 230000001179 pupillary effect Effects 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 210000001525 retina Anatomy 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 229910001936 tantalum oxide Inorganic materials 0.000 description 1
- 229910052714 tellurium Inorganic materials 0.000 description 1
- PORWMNRCUJJQNO-UHFFFAOYSA-N tellurium atom Chemical compound [Te] PORWMNRCUJJQNO-UHFFFAOYSA-N 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 238000012549 training Methods 0.000 description 1
- 230000001960 triggered effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/18—Diffraction gratings
- G02B5/1861—Reflection gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/01—Head-up displays
- G02B27/017—Head mounted
- G02B27/0172—Head mounted characterised by optical features
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/18—Diffraction gratings
- G02B5/1866—Transmission gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/0002—Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/01—Head-up displays
- G02B27/0101—Head-up displays characterised by optical features
- G02B2027/0123—Head-up displays characterised by optical features comprising devices increasing the field of view
- G02B2027/0125—Field-of-view increase by wavefront division
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/01—Head-up displays
- G02B27/017—Head mounted
- G02B2027/0178—Eyeglass type
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/18—Diffraction gratings
- G02B5/1847—Manufacturing methods
Definitions
- This disclosure relates generally to surface-relief gratings. More specifically, disclosed herein are techniques for forming low-loss, high-refractive index surface-relief gratings or overcoat layers of surface-relief gratings.
- An artificial reality system such as a head-mounted display (HMD) or heads-up display (HUD) system, generally includes a near-eye display (e.g., in the form of a headset or a pair of glasses) configured to present content to a user via an electronic or optic display within, for example, about 10-20 mm in front of the user’s eyes.
- the near-eye display may display virtual objects or combine images of real objects with virtual objects, as in virtual reality (VR), augmented reality (AR), or mixed reality (MR) applications.
- VR virtual reality
- AR augmented reality
- MR mixed reality
- a user may view both images of virtual objects (e.g., computer-generated images (CGIs)) and the surrounding environment by, for example, seeing through transparent display glasses or lenses (often referred to as optical see-through).
- CGIs computer-generated images
- an optical see-through AR system may use a waveguide-based optical display, where light of projected images may be coupled into a waveguide (e.g., a transparent substrate), propagate within the waveguide, and be coupled out of the waveguide at different locations.
- the light of the projected images may be coupled into or out of the waveguide using diffractive optical elements, such as surface-relief gratings or volume Bragg gratings. Light from the surrounding environment may pass through a see-through region of the waveguide and reach the user’s eyes as well.
- This disclosure relates generally to surface-relief gratings. More specifically, disclosed herein are techniques for forming low-loss, high-refractive index surface-relief gratings or overcoat layers of surface-relief gratings. Various inventive embodiments are described herein, including devices, systems, methods, processes, materials, compositions, and the like.
- an optical device may include a substrate, a first surface-relief grating including grooves and ridges formed on or in the substrate, a first overcoat layer in the grooves of the first surface-relief grating, and a first antireflective layer on the first overcoat layer.
- the ridges of the first surface-relief grating may include metal oxide nanoparticles and a material of the first overcoat layer in regions between the metal oxide nanoparticles, where the metal oxide nanoparticles may be photoactive.
- the first overcoat layer may include the metal oxide nanoparticles and a material of the first antireflective layer in regions between the metal oxide nanoparticles.
- the metal oxide nanoparticles may include TiOx nanoparticles, NbOx nanoparticles, or a combination thereof.
- the ridges of the first surface-relief grating or the first overcoat layer may be characterized by a refractive index greater than 2.0 for visible light.
- a total optical absorption of the first surface-relief grating and the first overcoat layer may be lower than 0.1% for visible light.
- the material in the regions between the metal oxide nanoparticles in the ridges of the first surface-relief grating or the material between the metal oxide nanoparticles in the first overcoat layer may include acrylate, polystyrenics, epoxy, siloxane, AI2O3, S1O2, ZrC , Nb20s, T1O2, Ta20.y or a combination thereof.
- the ridges of the first surface-relief grating or the first overcoat layer may have a carbon atomic concentration less than 10%, less than 5%, less than 2%, or less than 1%, such as close to about 0%.
- the optical device may also include a second surface-relief grating including grooves and ridges formed on or in the substrate, a second overcoat layer in the grooves of the second surface-relief grating, and a second antireflective layer on the second overcoat layer.
- the second surface-relief grating and the first surface-relief grating may be on opposite sides of the substrate.
- the ridges of the second surface-relief grating may include the metal oxide nanoparticles and a material of the second overcoat layer in regions between the metal oxide nanoparticles.
- the second overcoat layer may include the metal oxide nanoparticles and a material of the second antireflective layer in regions between the metal oxide nanoparticles.
- a method may include depositing an overcoat layer on a surface-relief grating to at least partially fill grating grooves of the surface-relief grating, curing the overcoat layer by heat or electromagnetic radiation, performing a high- energy treatment on the overcoat layer to remove light-absorbing organics and form porous structures in the overcoat layer, and depositing a first layer of an organic material, an inorganic material, or a combination thereof on the overcoat layer to fill the porous structures in the overcoat layer.
- the overcoat layer may include a sol-gel material including metal oxide precursors, or a resin layer including metal oxide nanoparticles.
- the method may include, before curing the overcoat layer, imprinting the overcoat layer using a planar imprint stamp to planarize a top surface of the overcoat layer.
- the high-energy treatment may include rapid thermal annealing (RTA), laser spike annealing (LSA), or ultraviolet (UV) light irradiation.
- Depositing the first layer of the organic material, the inorganic material, or a combination thereof on the overcoat layer may include an inkjet coating process, a spin coating process, an atomic layer deposition (ALD) process, a sequential infiltration synthesis (SIS) process, a physical vapor deposition (PVD) process, an initiated chemical vapor deposition (iCVD) process, or a combination thereof.
- ALD atomic layer deposition
- SIS sequential infiltration synthesis
- PVD physical vapor deposition
- iCVD initiated chemical vapor deposition
- ALD precursors used in the ALD process include TiCh and EhO, tetrakis (dimethylamino) htanium(IV) (TDMAT) and O3, tetrakis (dimethylamido) zirconium (IV) (TDMAZ) / trimethylaluminum (TMA) and H2O, or a combination thereof.
- the organic material may include acrylate, polystyrenics, epoxy, siloxane, or a combination thereof.
- the inorganic material may include, for example, AI2O3, SiCh, ZrCh, M>2q5, TiCh, Ta205, or a combination thereof.
- the sol-gel material may include organic solvent soluble Titania with organic ligands; and a solvent including propylene glycol methyl ether acetate (PGMEA), dipropylene glycol methyl ether (DPGME)/tripropylene glycol monomethyl ether (TPM), or a combination thereof.
- the resin layer may include an acrylate resin including photo radical generator or thermal radical generator; TiO x or NbOx nanoparticles decorated with organic ligands; and a solvent including PGMEA, DPGME/TPM, or a combination thereof.
- the first layer of the organic material, the inorganic material, or a combination thereof may form an antireflective coating layer on the overcoat layer.
- a method may include depositing, on a substrate, a resin layer that includes metal oxide nanoparticles; imprinting a surface-relief grating in the resin layer; performing a high-energy treatment on the surface-relief grating to remove light-absorbing organics and form porous structures in the surface-relief grating; and depositing a layer of an organic material, an inorganic material, or a combination thereof on the surface-relief grating to fill grating grooves of the surface-relief grating and the porous structures in the surface-relief grating.
- the high-energy treatment may include rapid thermal annealing (RTA), laser spike annealing (LSA), or ultraviolet (UV) light irradiation.
- the resin layer may include an acrylate resin including photo radical generator or thermal radical generator; TiCh or NbCL nanoparticles decorated with organic ligands; and a solvent including propylene glycol methyl ether acetate (PGMEA), dipropylene glycol methyl ether (DPGME)/tripropylene glycol monomethyl ether (TPM), or a combination thereof.
- RTA rapid thermal annealing
- LSA laser spike annealing
- UV ultraviolet
- the layer of the organic material, the inorganic material, or a combination thereof may include acrylate, polystyrenics, epoxy, siloxane, AI2O3, SiCh, ZrCh, MnCh, TiCh, Ta2Ch, or a combination thereof.
- FIG. 1 is a simplified block diagram of an example of an artificial reality system environment including a near-eye display according to certain embodiments.
- FIG. 2 is a perspective view of an example of a near-eye display in the form of a head-mounted display (HMD) device for implementing some of the examples disclosed herein.
- HMD head-mounted display
- FIG. 3 is a perspective view of an example of a near-eye display in the form of a pair of glasses for implementing some of the examples disclosed herein.
- FIG. 4 illustrates an example of an optical see-through augmented reality system including a waveguide display according to certain embodiments.
- FIG. 5 illustrates an example of an optical see-through augmented reality system including a waveguide display for exit pupil expansion according to certain embodiments.
- FIG. 6 illustrates examples of propagations of display light and external light in an example of a waveguide display.
- FIG. 7 illustrates an example of a slanted grating coupler in a waveguide display according to certain embodiments.
- FIG. 8A illustrates an example of a waveguide-based near-eye display where display light for all fields of view is substantially uniformly output from different regions of a waveguide display.
- FIG. 8B illustrates an example of a waveguide-based near-eye display where display light may be coupled out of a waveguide display at different angles in different regions of the waveguide display according to certain embodiments.
- FIG. 9A illustrates an example of a slanted surface-relief grating with variable etch depths according to certain embodiments.
- FIG. 9B illustrates an example of a slanted surface-relief grating with variable etch depths and variable duty cycles according to certain embodiments.
- FIGS. 10A-10D illustrate an example of a process for fabricating a soft stamp for nanoimprinting according to certain embodiments.
- FIG. 10A shows a master mold.
- FIG. 10B illustrates the master mold coated with a soft stamp material layer.
- FIG. IOC illustrates a lamination process for laminating a soft stamp foil onto the soft stamp material layer.
- FIG. 10D illustrates a delamination process, where the soft stamp including the soft stamp foil and the attached soft stamp material layer is detached from the master mold.
- FIGS. 11 A-l ID illustrate an example of an imprinting process using a soft stamp according to certain embodiments.
- FIG. 11 A shows a waveguide coated with an imprint resin layer.
- FIG. 1 IB shows the lamination of the soft stamp onto the imprint resin layer.
- FIG. 11C shows the delamination of the soft stamp from the imprint resin layer.
- FIG. 1 ID shows an example of an imprinted slanted grating formed on the waveguide.
- FIGS. 12A-12C illustrate an example of a method of forming a planarized overcoat layer on a surface-relief grating according to certain embodiments.
- FIGS. 13A-13B illustrate an example of a method of forming a planarized overcoat layer on a surface-relief grating using inkjet printing and imprinting techniques according to certain embodiments.
- FIG. 14A illustrates an example of the photocatalytic activity of TiCh nanoparticles.
- FIG. 14B illustrates an example of organic degradation caused by the photocatalytic activity of TiCh nanoparticles.
- FIGS. 15A-15D illustrate an example of a process of fabricating a surface-relief grating that includes overcoat layers with organics and metal oxide nanoparticles.
- FIG. 15E illustrates changes in the optical losses of examples of waveguide displays including surface-relief gratings having different metal oxide nanoparticles and organics during the fabrication processes.
- FIGS. 16A-16E illustrate an example of a process of fabricating a surface-relief grating including a high-refractive index and low-loss overcoat layer according to certain embodiments.
- FIG. 17A illustrates an example of a back-filled nanoparticle layers according to certain embodiments.
- FIG. 17B illustrates an example of a surface-relief grating including a back-filled high-refractive index overcoat layer according to certain embodiments.
- FIG. 18A illustrates an X-ray photoelectron spectroscopy (XPS) profile of an example of a structure including a substrate and a resin layer with organics removed by rapid thermal annealing (RTA) according to certain embodiments.
- XPS X-ray photoelectron spectroscopy
- FIG. 18B illustrates an XPS profile of an example of a structure including a substrate, a back-filled nanoparticle layer, and a back-fill layer according to certain embodiments.
- FIG. 18C illustrates an XPS profile of an example of a structure including a substrate, a back-filled nanoparticle layer, and an AI2O3 back-fill layer according to certain embodiments.
- FIG. 18D illustrates correlations between refractive indices and densities of various layers in the examples of structures of FIGS. 18A-18C.
- FIGS. 19A-19E illustrate an example of a process of fabricating a surface-relief grating including an overcoat layer having a high refractive index and a low loss according to certain embodiments.
- FIGS. 20A-20E illustrate an example of a process of fabricating a surface-relief grating including grating ridges having a high refractive index and a low loss according to certain embodiments.
- FIG. 21 includes a flowchart illustrating an example of a process of fabricating a surface-relief grating having a high refractive index contrast and a low loss according to certain embodiments.
- FIG. 22 is a simplified block diagram of an example electronic system of an example near-eye display for implementing some of the examples disclosed herein.
- This disclosure relates generally to surface-relief gratings. More specifically, disclosed herein are techniques for forming low-loss, high-refractive index surface-relief gratings or overcoat layers of surface-relief gratings. Various inventive embodiments are described herein, including devices, systems, methods, processes, materials, compositions, and the like.
- Surface-relief gratings may be used in some optical devices to manipulate behavior of light.
- straight or slanted surface-relief gratings may be used in near-eye display systems to couple display light into or out of a waveguide.
- An overcoat layer having a refractive index different from the refractive index of the grating ridges of the surface-relief grating may be formed on the surface-relief gratings to fill the grating grooves and protect the straight or slanted structures.
- the grating ridges may be made using a high- refractive index nanoimprinting material (e.g., a resin with high-refractive index metal oxide nanoparticles), and an overcoat layer with a low refractive index may be used to achieve the large refractive index contrast.
- a high- refractive index nanoimprinting material e.g., a resin with high-refractive index metal oxide nanoparticles
- the grating ridges may be made of a low-refractive index material (e.g., glass), and an overcoat layer with a high refractive index (e.g., about 2.0 or larger) may be used to achieve the large refractive index contrast.
- a low-refractive index material e.g., glass
- an overcoat layer with a high refractive index e.g., about 2.0 or larger
- the high-refractive index material for the grating ridges or the overcoat layer may include a resin dispersed with high-refractive index nanoparticles, such as TiCh nanoparticles, NbOx nanoparticles, ZrCh nanoparticles, and the like, or may include a sol-gel material that includes a solution and a high-refractive index oxide precursor (e.g., Ti precursor) and has been partially or fully condensed into an extended network.
- a resin dispersed with high-refractive index nanoparticles such as TiCh nanoparticles, NbOx nanoparticles, ZrCh nanoparticles, and the like
- a sol-gel material that includes a solution and a high-refractive index oxide precursor (e.g., Ti precursor) and has been partially or fully condensed into an extended network.
- TiCh has a higher refractive index (e.g., greater than about 2.5 for visible light) than ZrCh (e.g., about 2.15 for visible light) and other dielectric materials (e.g., metal oxides such as NbOx, LaOx, TaOx, AhCh, etc.), and thus may be mixed with a resin material to form a high-refractive index resin (e.g., with a refractive index about 2.0 or higher).
- high- refractive index resin materials such as organics mixed with TiCh particles, may have high absorption in visible wavelengths, and the absorption may increase during the fabrication and usage of the devices made of these high-refractive index resin materials.
- TiCh nanoparticles exposed to ultraviolet (UV) light may interact with moisture and/or oxygen to generate radicals (e.g., hydroxyl radicals) that may oxidize and degrade organics (e.g., ligands and resin) in the high-refractive index resin materials, where the degraded organics may absorb visible light.
- radicals e.g., hydroxyl radicals
- degrade organics e.g., ligands and resin
- TiCh nanoparticles Due to their high surface- volume ratios, TiCh nanoparticles may have high light absorption rates, which may increase the surface photo-induced carrier density that can lead to higher surface photoactivity and enhanced photocatalytic activity of TiCh nanoparticles.
- films including titanium oxide nanoparticles and organics may show some levels of light absorption in the visible spectrum.
- the absorption of the films may increase over time, as the films undergo further redox interactions with their environment, such as upon exposure to ultraviolet (UV) light and heat.
- UV ultraviolet
- Surface-relief gratings and/or overcoat layers made of the high-absorption films may lead to high loss and low throughput for waveguide displays.
- organics in an imprinted grating layer or an overcoat layer such as organic ligands on metal oxide (e.g., TiCh or NbOx) nanoparticles that may have been degraded (oxidized) or may not have been degraded, may be removed and/or replaced with another material, such as an inorganic material (e.g., Si-containing material) or another organic material that may have a low optical loss and may not be degraded by the photocatalytic activity of the metal oxide nanoparticles.
- metal oxide e.g., TiCh or NbOx
- another material such as an inorganic material (e.g., Si-containing material) or another organic material that may have a low optical loss and may not be degraded by the photocatalytic activity of the metal oxide nanoparticles.
- the organic ligands on metal oxide nanoparticles in a grating layer or an overcoat layer may be removed (e.g., burned) by a high-energy treatment process, such as rapid thermal annealing (RTA) or laser spike annealing (LSA), to form porous structures in the grating layer or the overcoat layer.
- a high-energy treatment process such as rapid thermal annealing (RTA) or laser spike annealing (LSA)
- An organic or inorganic material layer (e.g., an overcoat layer or an antireflective coating layer) may then be formed on the grating layer or the overcoat layer to fill the porous structures in the grating layer or the overcoat layer, thereby increasing the refractive index while reducing the absorption loss of the grating layer or the overcoat layer.
- a method of forming a high-refractive index and low-loss overcoat layer on a surface-relief grating may include depositing a first overcoat layer including high- refractive index nanoparticles dispersed in a resin material on a first side of a surface-relief grating to at least partially fill grating grooves of the surface relief grating; optionally imprinting the first overcoat layer to form a planar top surface on the first overcoat layer; curing the first overcoat layer by heat or electromagnetic radiation; optionally depositing a second overcoat layer including the nanoparticles dispersed in the resin material on a second side of the surface-relief grating; optionally curing the second overcoat layer by heat or electromagnetic radiation; performing RTA or LSA on the first overcoat layer and the second overcoat layer to remove light-absorbing organic ligands on the nanoparticles and form porous structures in the first overcoat layer and the second overcoat layer; and depositing an organic and/
- a method of forming a high-refractive index and low-loss surface-relief grating may include depositing, on a substrate, a resin layer that includes metal oxide nanoparticles; imprinting a surface-relief grating in the resin layer; performing a high- energy treatment on the surface-relief grating to remove light-absorbing organics and form porous structures in the surface-relief grating; and depositing a layer of an organic material, an inorganic material, or a combination thereof on the surface-relief grating using, for example, an inkjet coating process, a spin coating process, an ALD process, an SIS process, a PVD process, or an iCVD process, to fill the porous structures in the surface-relief grating.
- the high-refractive index material for imprinting the surface-relief grating or the overcoat layer may include a nanoparticle-based formulation or a sol-gel-based formulation.
- the nanoparticle-based formulation, sol-gel-based formulation, or a mixture of the two types of formulation can be annealed using RTA or LSA to form porous structures in the imprinted surface-relief grating or the overcoat layer.
- the imprinted surface-relief grating or the overcoat layer with the porous structures may be back filled with an organic and/or inorganic material to achieve a high refractive index and ultra- low absorption.
- the organic and/or inorganic material that fills the porous structures can have low optical loss, and may include, for example, organic materials such as acrylate, polystyrenics, epoxy based organic materials; siloxane-based materials; inorganic materials such as AI2O3, S1O2, ZrC , M>2q5, TiC , Ta20s, and the like; or a combination of organic materials and inorganic materials describe above.
- organic materials such as acrylate, polystyrenics, epoxy based organic materials; siloxane-based materials; inorganic materials such as AI2O3, S1O2, ZrC , M>2q5, TiC , Ta20s, and the like; or a combination of organic materials and inorganic materials describe above.
- the sol-gel-based formulation may include EMD MHM-63, Philips high-refractive index sol-gel formulation, or organic solvent soluble Titania with ligands in PGMEA solvent (for spin coating) or DPGME/TPM solvent (for inkjet coating).
- the nanoparticle-based formulation may include acrylate resin (with a refractive index between about 1.55 and about 1.7) with photo radical generator or thermal radical generator; 75%-90% TiOx, ZrOx, NbOx nanoparticles with acrylate and non-functional decoration ligands; and propylene glycol methyl ether acetate (PGMEA) solvent (for spin coating), dipropylene glycol methyl ether (DPGME)/ tripropylene glycol monomethyl ether (TPM) solvent (for inkjet coating), or a solvent blend including one or more solvents that may or may not have boiling points greater than 200°C.
- acrylate resin with a refractive index between about 1.55 and about 1.7
- photo radical generator or thermal radical generator 75%-90% TiOx, ZrOx, NbOx nanoparticles with acrylate and non-functional decoration ligands
- PMEA propylene glycol methyl ether acetate
- DPGME dipropylene glycol
- the ALD precursor may include TiCU and H2O, tetrakis (dimethyl amino) titanium(IV) (TDMAT) and O3, tetrakis (dimethylamido) zirconium (IV) (TDMAZ) / trimethylaluminum (TMA) and H2O, or the like.
- the term “about” means that dimensions, sizes, formulations, parameters, shapes and other quantities and characteristics are not and need not be exact, but may be approximate and/or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art.
- a dimension, size, formulation, parameter, shape or other quantity or characteristic is “about” or “approximate” whether or not expressly stated to be such. It is noted that embodiments of very different sizes, shapes and dimensions may employ the described arrangements.
- FIG. 1 is a simplified block diagram of an example of an artificial reality system environment 100 including a near-eye display 120 in accordance with certain embodiments.
- Artificial reality system environment 100 shown in FIG. 1 may include near-eye display 120, an optional external imaging device 150, and an optional input/output interface 140, each of which may be coupled to an optional console 110. While FIG. 1 shows an example of artificial reality system environment 100 including one near-eye display 120, one external imaging device 150, and one input/output interface 140, any number of these components may be included in artificial reality system environment 100, or any of the components may be omitted. For example, there may be multiple near-eye displays 120 monitored by one or more external imaging devices 150 in communication with console 110. In some configurations, artificial reality system environment 100 may not include external imaging device 150, optional input/output interface 140, and optional console 110. In alternative configurations, different or additional components may be included in artificial reality system environment 100.
- Near-eye display 120 may be a head-mounted display that presents content to a user. Examples of content presented by near-eye display 120 include one or more of images, videos, audio, or any combination thereof. In some embodiments, audio may be presented via an external device (e.g, speakers and/or headphones) that receives audio information from near-eye display 120, console 110, or both, and presents audio data based on the audio information.
- Near-eye display 120 may include one or more rigid bodies, which may be rigidly or non-rigidly coupled to each other. A rigid coupling between rigid bodies may cause the coupled rigid bodies to act as a single rigid entity. A non-rigid coupling between rigid bodies may allow the rigid bodies to move relative to each other.
- near-eye display 120 may be implemented in any suitable form-factor, including a pair of glasses. Some embodiments of near-eye display 120 are further described below with respect to FIGS. 2 and 3. Additionally, in various embodiments, the functionality described herein may be used in a headset that combines images of an environment external to near-eye display 120 and artificial reality content (e.g., computer-generated images). Therefore, near eye display 120 may augment images of a physical, real-world environment external to near eye display 120 with generated content (e.g, images, video, sound, etc.) to present an augmented reality to a user.
- artificial reality content e.g., computer-generated images
- near-eye display 120 may include one or more of display electronics 122, display optics 124, and an eye-tracking unit 130.
- near-eye display 120 may also include one or more locators 126, one or more position sensors 128, and an inertial measurement unit (IMU) 132.
- IMU inertial measurement unit
- Near-eye display 120 may omit any of eye tracking unit 130, locators 126, position sensors 128, and IMU 132, or include additional elements in various embodiments.
- near-eye display 120 may include elements combining the function of various elements described in conjunction with FIG. 1.
- Display electronics 122 may display or facilitate the display of images to the user according to data received from, for example, console 110.
- display electronics 122 may include one or more display panels, such as a liquid crystal display (LCD), an organic light emitting diode (OLED) display, an inorganic light emitting diode (ILED) display, a micro light emitting diode (pLED) display, an active-matrix OLED display (AMOLED), a transparent OLED display (TOLED), or some other display.
- LCD liquid crystal display
- OLED organic light emitting diode
- ILED inorganic light emitting diode
- pLED micro light emitting diode
- AMOLED active-matrix OLED display
- TOLED transparent OLED display
- display electronics 122 may include a front TOLED panel, a rear display panel, and an optical component (e.g., an attenuator, polarizer, or diffractive or spectral film) between the front and rear display panels.
- Display electronics 122 may include pixels to emit light of a predominant color such as red, green, blue, white, or yellow.
- display electronics 122 may display a three-dimensional (3D) image through stereoscopic effects produced by two-dimensional panels to create a subjective perception of image depth.
- display electronics 122 may include a left display and a right display positioned in front of a user’s left eye and right eye, respectively. The left and right displays may present copies of an image shifted horizontally relative to each other to create a stereoscopic effect (i.e., a perception of image depth by a user viewing the image).
- display optics 124 may display image content optically (e.g., using optical waveguides and couplers) or magnify image light received from display electronics 122, correct optical errors associated with the image light, and present the corrected image light to a user of near-eye display 120.
- display optics 124 may include one or more optical elements, such as, for example, a substrate, optical waveguides, an aperture, a Fresnel lens, a convex lens, a concave lens, a filter, input/output couplers, or any other suitable optical elements that may affect image light emitted from display electronics 122.
- Display optics 124 may include a combination of different optical elements as well as mechanical couplings to maintain relative spacing and orientation of the optical elements in the combination.
- One or more optical elements in display optics 124 may have an optical coating, such as an antireflective coating, a reflective coating, a filtering coating, or a combination of different optical coatings.
- Magnification of the image light by display optics 124 may allow display electronics 122 to be physically smaller, weigh less, and consume less power than larger displays. Additionally, magnification may increase a field of view of the displayed content. The amount of magnification of image light by display optics 124 may be changed by adjusting, adding, or removing optical elements from display optics 124. In some embodiments, display optics 124 may project displayed images to one or more image planes that may be further away from the user’s eyes than near-eye display 120.
- Display optics 124 may also be designed to correct one or more types of optical errors, such as two-dimensional optical errors, three-dimensional optical errors, or any combination thereof.
- Two-dimensional errors may include optical aberrations that occur in two dimensions.
- Example types of two-dimensional errors may include barrel distortion, pincushion distortion, longitudinal chromatic aberration, and transverse chromatic aberration.
- Three-dimensional errors may include optical errors that occur in three dimensions.
- Example types of three-dimensional errors may include spherical aberration, comatic aberration, field curvature, and astigmatism.
- Locators 126 may be objects located in specific positions on near-eye display 120 relative to one another and relative to a reference point on near-eye display 120.
- console 110 may identify locators 126 in images captured by external imaging device 150 to determine the artificial reality headset’s position, orientation, or both.
- a locator 126 may be a light-emitting diode (LED), a comer cube reflector, a reflective marker, a type of light source that contrasts with an environment in which near-eye display 120 operates, or any combination thereof.
- LED light-emitting diode
- comer cube reflector a comer cube reflector
- a reflective marker a type of light source that contrasts with an environment in which near-eye display 120 operates, or any combination thereof.
- locators 126 may emit light in the visible band (e.g., about 380 nm to 750 nm), in the infrared (IR) band (e.g., about 750 nm to 1 mm), in the ultraviolet band (e.g, about 10 nm to about 380 nm), in another portion of the electromagnetic spectrum, or in any combination of portions of the electromagnetic spectrum.
- visible band e.g., about 380 nm to 750 nm
- IR infrared
- ultraviolet band e.g., about 10 nm to about 380 nm
- External imaging device 150 may include one or more cameras, one or more video cameras, any other device capable of capturing images including one or more of locators 126, or any combination thereof. Additionally, external imaging device 150 may include one or more filters (e.g., to increase signal to noise ratio). External imaging device 150 may be configured to detect light emitted or reflected from locators 126 in a field of view of external imaging device 150. In embodiments where locators 126 include passive elements (e.g., retroreflectors), external imaging device 150 may include a light source that illuminates some or all of locators 126, which may retro-reflect the light to the light source in external imaging device 150.
- locators 126 include passive elements (e.g., retroreflectors)
- external imaging device 150 may include a light source that illuminates some or all of locators 126, which may retro-reflect the light to the light source in external imaging device 150.
- Position sensors 128 may generate one or more measurement signals in response to motion of near-eye display 120. Examples of position sensors 128 may include accelerometers, gyroscopes, magnetometers, other motion-detecting or error-correcting sensors, or any combination thereof.
- position sensors 128 may include multiple accelerometers to measure translational motion (e.g., forward/back, up/down, or left/right) and multiple gyroscopes to measure rotational motion (e.g., pitch, yaw, or roll).
- various position sensors may be oriented orthogonally to each other.
- IMU 132 may be an electronic device that generates fast calibration data based on measurement signals received from one or more of position sensors 128. Position sensors 128 may be located external to IMU 132, internal to IMU 132, or any combination thereof. Based on the one or more measurement signals from one or more position sensors 128, IMU 132 may generate fast calibration data indicating an estimated position of near-eye display 120 relative to an initial position of near-eye display 120. For example, IMU 132 may integrate measurement signals received from accelerometers over time to estimate a velocity vector and integrate the velocity vector over time to determine an estimated position of a reference point on near-eye display 120. Alternatively, IMU 132 may provide the sampled measurement signals to console 110, which may determine the fast calibration data. While the reference point may generally be defined as a point in space, in various embodiments, the reference point may also be defined as a point within near-eye display 120 (e.g., a center of IMU 132).
- Eye-tracking unit 130 may include one or more eye-tracking systems. Eye tracking may refer to determining an eye’s position, including orientation and location of the eye, relative to near-eye display 120.
- An eye-tracking system may include an imaging system to image one or more eyes and may optionally include a light emitter, which may generate light that is directed to an eye such that light reflected by the eye may be captured by the imaging system.
- eye-tracking unit 130 may include a non-coherent or coherent light source (e.g., a laser diode) emitting light in the visible spectrum or infrared spectrum, and a camera capturing the light reflected by the user’s eye.
- a non-coherent or coherent light source e.g., a laser diode
- eye-tracking unit 130 may capture reflected radio waves emitted by a miniature radar unit. Eye-tracking unit 130 may use low-power light emitters that emit light at frequencies and intensities that would not injure the eye or cause physical discomfort. Eye-tracking unit 130 may be arranged to increase contrast in images of an eye captured by eye-tracking unit 130 while reducing the overall power consumed by eye-tracking unit 130 (e.g., reducing power consumed by a light emitter and an imaging system included in eye-tracking unit 130). For example, in some implementations, eye-tracking unit 130 may consume less than 100 milliwatts of power.
- Near-eye display 120 may use the orientation of the eye to, e.g., determine an inter pupillary distance (IPD) of the user, determine gaze direction, introduce depth cues (e.g., blur image outside of the user’s main line of sight), collect heuristics on the user interaction in the VR media (e.g., time spent on any particular subject, object, or frame as a function of exposed stimuli), some other functions that are based in part on the orientation of at least one of the user’s eyes, or any combination thereof. Because the orientation may be determined for both eyes of the user, eye-tracking unit 130 may be able to determine where the user is looking.
- IPD inter pupillary distance
- determining a direction of a user’s gaze may include determining a point of convergence based on the determined orientations of the user’s left and right eyes.
- a point of convergence may be the point where the two foveal axes of the user’s eyes intersect.
- the direction of the user’s gaze may be the direction of a line passing through the point of convergence and the mid-point between the pupils of the user’s eyes.
- Input/output interface 140 may be a device that allows a user to send action requests to console 110.
- An action request may be a request to perform a particular action.
- An action request may be to start or to end an application or to perform a particular action within the application.
- Input/output interface 140 may include one or more input devices.
- Example input devices may include a keyboard, a mouse, a game controller, a glove, a button, a touch screen, or any other suitable device for receiving action requests and communicating the received action requests to console 110.
- An action request received by the input/output interface 140 may be communicated to console 110, which may perform an action corresponding to the requested action.
- input/output interface 140 may provide haptic feedback to the user in accordance with instructions received from console 110. For example, input/output interface 140 may provide haptic feedback when an action request is received, or when console 110 has performed a requested action and communicates instructions to input/output interface 140.
- external imaging device 150 may be used to track input/output interface 140, such as tracking the location or position of a controller (which may include, for example, an IR light source) or a hand of the user to determine the motion of the user.
- near-eye display 120 may include one or more imaging devices to track input/output interface 140, such as tracking the location or position of a controller or a hand of the user to determine the motion of the user.
- Console 110 may provide content to near-eye display 120 for presentation to the user in accordance with information received from one or more of external imaging device 150, near-eye display 120, and input/output interface 140.
- console 110 may include an application store 112, a headset tracking module 114, an artificial reality engine 116, and an eye-tracking module 118.
- Some embodiments of console 110 may include different or additional modules than those described in conjunction with FIG. 1. Functions further described below may be distributed among components of console 110 in a different manner than is described here.
- console 110 may include a processor and a non-transitory computer-readable storage medium storing instructions executable by the processor.
- the processor may include multiple processing units executing instructions in parallel.
- the non- transitory computer-readable storage medium may be any memory, such as a hard disk drive, a removable memory, or a solid-state drive (e.g ., flash memory or dynamic random access memory (DRAM)).
- the modules of console 110 described in conjunction with FIG. 1 may be encoded as instructions in the non-transitory computer- readable storage medium that, when executed by the processor, cause the processor to perform the functions further described below.
- Application store 112 may store one or more applications for execution by console 110.
- An application may include a group of instructions that, when executed by a processor, generates content for presentation to the user. Content generated by an application may be in response to inputs received from the user via movement of the user’s eyes or inputs received from the input/output interface 140. Examples of the applications may include gaming applications, conferencing applications, video playback application, or other suitable applications.
- Headset tracking module 114 may track movements of near-eye display 120 using slow calibration information from external imaging device 150. For example, headset tracking module 114 may determine positions of a reference point of near-eye display 120 using observed locators from the slow calibration information and a model of near-eye display 120. Headset tracking module 114 may also determine positions of a reference point of near-eye display 120 using position information from the fast calibration information. Additionally, in some embodiments, headset tracking module 114 may use portions of the fast calibration information, the slow calibration information, or any combination thereof, to predict a future location of near-eye display 120. Headset tracking module 114 may provide the estimated or predicted future position of near-eye display 120 to artificial reality engine 116.
- Artificial reality engine 116 may execute applications within artificial reality system environment 100 and receive position information of near-eye display 120, acceleration information of near-eye display 120, velocity information of near-eye display 120, predicted future positions of near-eye display 120, or any combination thereof from headset tracking module 114. Artificial reality engine 116 may also receive estimated eye position and orientation information from eye-tracking module 118. Based on the received information, artificial reality engine 116 may determine content to provide to near-eye display 120 for presentation to the user. For example, if the received information indicates that the user has looked to the left, artificial reality engine 116 may generate content for near-eye display 120 that mirrors the user’s eye movement in a virtual environment.
- Eye-tracking module 118 may receive eye-tracking data from eye-tracking unit 130 and determine the position of the user’s eye based on the eye tracking data.
- the position of the eye may include an eye’s orientation, location, or both relative to near-eye display 120 or any element thereof. Because the eye’s axes of rotation change as a function of the eye’s location in its socket, determining the eye’s location in its socket may allow eye-tracking module 118 to more accurately determine the eye’s orientation.
- FIG. 2 is a perspective view of an example of a near-eye display in the form of an HMD device 200 for implementing some of the examples disclosed herein.
- HMD device 200 may be a part of, e.g., a VR system, an AR system, an MR system, or any combination thereof.
- HMD device 200 may include a body 220 and a head strap 230.
- FIG. 2 shows a bottom side 223, a front side 225, and a left side 227 of body 220 in the perspective view.
- Head strap 230 may have an adjustable or extendible length. There may be a sufficient space between body 220 and head strap 230 of HMD device 200 for allowing a user to mount HMD device 200 onto the user’s head.
- HMD device 200 may include additional, fewer, or different components.
- HMD device 200 may include eyeglass temples and temple tips as shown in, for example, FIG. 3 below, rather than head strap 230.
- HMD device 200 may present to a user media including virtual and/or augmented views of a physical, real-world environment with computer-generated elements.
- Examples of the media presented by HMD device 200 may include images (e.g., two-dimensional (2D) or three-dimensional (3D) images), videos (e.g., 2D or 3D videos), audio, or any combination thereof.
- the images and videos may be presented to each eye of the user by one or more display assemblies (not shown in FIG. 2) enclosed in body 220 of HMD device 200.
- the one or more display assemblies may include a single electronic display panel or multiple electronic display panels (e.g., one display panel for each eye of the user).
- HMD device 200 may include, for example, an LCD, an OLED display, an ILED display, a pLED display, an AMOLED, a TOLED, some other display, or any combination thereof.
- HMD device 200 may include two eye box regions. [0079]
- HMD device 200 may include various sensors (not shown), such as depth sensors, motion sensors, position sensors, and eye tracking sensors. Some of these sensors may use a structured light pattern for sensing.
- HMD device 200 may include an input/output interface for communicating with a console.
- HMD device 200 may include a virtual reality engine (not shown) that can execute applications within HMD device 200 and receive depth information, position information, acceleration information, velocity information, predicted future positions, or any combination thereof of HMD device 200 from the various sensors.
- the information received by the virtual reality engine may be used for producing a signal (e.g., display instructions) to the one or more display assemblies.
- HMD device 200 may include locators (not shown, such as locators 126) located in fixed positions on body 220 relative to one another and relative to a reference point. Each of the locators may emit light that is detectable by an external imaging device. [0080] FIG.
- Near-eye display 300 may be a specific implementation of near-eye display 120 of FIG. 1, and may be configured to operate as a virtual reality display, an augmented reality display, and/or a mixed reality display.
- Near-eye display 300 may include a frame 305 and a display 310.
- Display 310 may be configured to present content to a user.
- display 310 may include display electronics and/or display optics.
- display 310 may include an LCD display panel, an LED display panel, or an optical display panel (e.g., a waveguide display assembly).
- Near-eye display 300 may further include various sensors 350a, 350b, 350c, 350d, and 350e on or within frame 305.
- sensors 350a-350e may include one or more depth sensors, motion sensors, position sensors, inertial sensors, or ambient light sensors.
- sensors 350a-350e may include one or more image sensors configured to generate image data representing different fields of views in different directions.
- sensors 350a-350e may be used as input devices to control or influence the displayed content of near-eye display 300, and/or to provide an interactive VR/AR/MR experience to a user of near-eye display 300.
- sensors 350a-350e may also be used for stereoscopic imaging.
- near-eye display 300 may further include one or more illuminators 330 to project light into the physical environment.
- the projected light may be associated with different frequency bands (e.g., visible light, infra-red light, ultra-violet light, etc.), and may serve various purposes.
- illuminator(s) 330 may project light in a dark environment (or in an environment with low intensity of infra-red light, ultra-violet light, etc.) to assist sensors 350a-350e in capturing images of different objects within the dark environment.
- illuminator(s) 330 may be used to project certain light patterns onto the objects within the environment.
- illuminator(s) 330 may be used as locators, such as locators 126 described above with respect to FIG. 1.
- near-eye display 300 may also include a high-resolution camera 340.
- High-resolution camera 340 may capture images of the physical environment in the field of view. The captured images may be processed, for example, by a virtual reality engine (e.g., artificial reality engine 116 of FIG. 1) to add virtual objects to the captured images or modify physical objects in the captured images, and the processed images may be displayed to the user by display 310 for AR or MR applications.
- a virtual reality engine e.g., artificial reality engine 116 of FIG. 1
- the processed images may be displayed to the user by display 310 for AR or MR applications.
- FIG. 4 illustrates an example of an optical see-through augmented reality system 400 including a waveguide display according to certain embodiments.
- Augmented reality system 400 may include a projector 410 and a combiner 415.
- Projector 410 may include a light source or image source 412 and projector optics 414.
- light source or image source 412 may include one or more micro-LED devices described above.
- image source 412 may include a plurality of pixels that displays virtual objects, such as an LCD display panel or an LED display panel.
- image source 412 may include a light source that generates coherent or partially coherent light.
- image source 412 may include a laser diode, a vertical cavity surface emitting laser, an LED, and/or a micro-LED described above.
- image source 412 may include a plurality of light sources (e.g., an array of micro-LEDs described above), each emitting a monochromatic image light corresponding to a primary color (e.g., red, green, or blue).
- image source 412 may include three two-dimensional arrays of micro-LEDs, where each two-dimensional array of micro-LEDs may include micro-LEDs configured to emit light of a primary color (e.g., red, green, or blue).
- image source 412 may include an optical pattern generator, such as a spatial light modulator.
- Projector optics 414 may include one or more optical components that can condition the light from image source 412, such as expanding, collimating, scanning, or projecting light from image source 412 to combiner 415.
- the one or more optical components may include, for example, one or more lenses, liquid lenses, mirrors, apertures, and/or gratings.
- image source 412 may include one or more one-dimensional arrays or elongated two-dimensional arrays of micro-LEDs
- projector optics 414 may include one or more one-dimensional scanners (e.g., micro-mirrors or prisms) configured to scan the one dimensional arrays or elongated two-dimensional arrays of micro-LEDs to generate image frames.
- projector optics 414 may include a liquid lens (e.g., a liquid crystal lens) with a plurality of electrodes that allows scanning of the light from image source 412.
- Combiner 415 may include an input coupler 430 for coupling light from projector 410 into a substrate 420 of combiner 415.
- Combiner 415 may transmit at least 50% of light in a first wavelength range and reflect at least 25% of light in a second wavelength range.
- the first wavelength range may be visible light from about 400 nm to about 650 nm
- the second wavelength range may be in the infrared band, for example, from about 800 nm to about 1000 nm.
- Input coupler 430 may include a volume holographic grating, a diffractive optical element (DOE) (e.g., a surface-relief grating), a slanted surface of substrate 420, or a refractive coupler (e.g., a wedge or a prism).
- DOE diffractive optical element
- input coupler 430 may include a reflective volume Bragg grating or a transmissive volume Bragg grating.
- Input coupler 430 may have a coupling efficiency of greater than 30%, 50%, 75%, 90%, or higher for visible light.
- Light coupled into substrate 420 may propagate within substrate 420 through, for example, total internal reflection (TIR).
- TIR total internal reflection
- Substrate 420 may be in the form of a lens of a pair of eyeglasses.
- Substrate 420 may have a flat or a curved surface, and may include one or more types of dielectric materials, such as glass, quartz, plastic, polymer, poly(methyl methacrylate) (PMMA), crystal, or ceramic.
- a thickness of the substrate may range from, for example, less than about 1 mm to about 10 mm or more.
- Substrate 420 may be transparent to visible light.
- Substrate 420 may include or may be coupled to a plurality of output couplers 440, each configured to extract at least a portion of the light guided by and propagating within substrate 420 from substrate 420, and direct extracted light 460 to an eyebox 495 where an eye 490 of the user of augmented reality system 400 may be located when augmented reality system 400 is in use.
- the plurality of output couplers 440 may replicate the exit pupil to increase the size of eyebox 495 such that the displayed image is visible in a larger area.
- output couplers 440 may include grating couplers (e.g., volume holographic gratings or surface-relief gratings), other diffraction optical elements, prisms, etc.
- output couplers 440 may include reflective volume Bragg gratings or transmissive volume Bragg gratings. Output couplers 440 may have different coupling (e.g., diffraction) efficiencies at different locations. Substrate 420 may also allow light 450 from the environment in front of combiner 415 to pass through with little or no loss. Output couplers 440 may also allow light 450 to pass through with little loss. For example, in some implementations, output couplers 440 may have a very low diffraction efficiency for light 450 such that light 450 may be refracted or otherwise pass through output couplers 440 with little loss, and thus may have a higher intensity than extracted light 460.
- output couplers 440 may have a high diffraction efficiency for light 450 and may diffract light 450 in certain desired directions (i.e., diffraction angles) with little loss. As a result, the user may be able to view combined images of the environment in front of combiner 415 and images of virtual objects projected by projector 410.
- projector 410, input coupler 430, and output coupler 440 may be on any side of substrate 420.
- Input coupler 430 and output coupler 440 may be reflective gratings (also referred to as reflective gratings) or transmissive gratings (also referred to as transmissive gratings) to couple display light into or out of substrate 420.
- FIG. 5 illustrates an example of an optical see-through augmented reality system 500 including a waveguide display for exit pupil expansion according to certain embodiments.
- Augmented reality system 500 may be similar to augmented reality system 500, and may include the waveguide display and a projector that may include a light source or image source 510 and projector optics 520.
- the waveguide display may include a substrate 530, an input coupler 540, and a plurality of output couplers 550 as described above with respect to augmented reality system 500. While FIG. 5 only shows the propagation of light from a single field of view, FIG. 5 shows the propagation of light from multiple fields of view.
- FIG. 5 shows that the exit pupil is replicated by output couplers 550 to form an aggregated exit pupil or eyebox, where different regions in a field of view (e.g., different pixels on image source 510) may be associated with different respective propagation directions towards the eyebox, and light from a same field of view (e.g., a same pixel on image source 510) may have a same propagation direction for the different individual exit pupils.
- a single image of image source 510 may be formed by the user’s eye located anywhere in the eyebox, where light from different individual exit pupils and propagating in the same direction may be from a same pixel on image source 510 and may be focused onto a same location on the retina of the user’s eye.
- FIG. 1 shows that the exit pupil is replicated by output couplers 550 to form an aggregated exit pupil or eyebox, where different regions in a field of view (e.g., different pixels on image source 510) may be associated with different respective propagation directions towards the eyebox, and light from a same field of view
- FIG. 6 illustrates propagations of display light 640 and external light 630 in an example waveguide display 600 including a waveguide 610 and a grating coupler 620.
- Waveguide 610 may be a flat or curved transparent substrate with a refractive index m greater than the free space refractive index m (e.g., 1.0).
- Grating coupler 620 may be, for example, a Bragg grating or a surface-relief grating.
- Display light 640 may be coupled into waveguide 610 by, for example, input coupler 430 of FIG. 4 or other couplers (e.g., a prism or slanted surface) described above. Display light 640 may propagate within waveguide 610 through, for example, total internal reflection. When display light 640 reaches grating coupler 620, display light 640 may be diffracted by grating coupler 620 into, for example, a 0 th order diffraction (i.e., reflection) light 642 and a -1st order diffraction light 644.
- a 0 th order diffraction i.e., reflection
- the 0 th order diffraction may propagate within waveguide 610, and may be reflected by the bottom surface of waveguide 610 towards grating coupler 620 at a different location.
- the -1st order diffraction light 644 may be coupled (e.g, refracted) out of waveguide 610 towards the user’s eye, because a total internal reflection condition may not be met at the bottom surface of waveguide 610 due to the diffraction angle.
- External light 630 may also be diffracted by grating coupler 620 into, for example, a 0 th order diffraction light 632 and a -1st order diffraction light 634. Both the 0 th order diffraction light 632 and the -1st order diffraction light 634 may be refracted out of waveguide 610 towards the user’s eye.
- grating coupler 620 may act as an input coupler for coupling external light 630 into waveguide 610, and may also act as an output coupler for coupling display light 640 out of waveguide 610.
- grating coupler 620 may act as a combiner for combining external light 630 and display light 640.
- grating coupler 620 e.g., a surface-relief grating coupler
- external light 630 i.e., transmissive diffraction
- grating coupler 620 for display light 640 i.e., reflective diffraction
- grating coupler 620 may include a blazed or slanted grating, such as a slanted Bragg grating or surface-relief grating, where the grating ridges and grooves may be tilted relative to the surface normal of grating coupler 620 or waveguide 610.
- FIG. 7 illustrates an example of a slanted grating 720 in a waveguide display 700 according to certain embodiments.
- Slanted grating 720 may be an example of input coupler 430, output couplers 440, or grating coupler 620.
- Waveguide display 700 may include slanted grating 720 on a waveguide 710, such as substrate 420 or waveguide 610.
- Slanted grating 720 may act as a grating coupler for couple light into or out of waveguide 710.
- slanted grating 720 may include a one-dimensional periodic structure with a period p.
- slanted grating 720 may include a plurality of ridges 722 and grooves 724 between ridges 722.
- Each period of slanted grating 720 may include a ridge 722 and a groove 724, which may be an air gap or a region filled with a material with a refractive index n 2.
- the ratio between the width d of a ridge 722 and the grating period p may be referred to as duty cycle.
- Slanted grating 720 may have a duty cycle ranging, for example, from about 10% to about 90% or greater. In some embodiments, the duty cycle may vary from period to period.
- the period p of the slanted grating may vary from one area to another on slanted grating 720, or may vary from one period to another (i.e., chirped) on slanted grating 720.
- Ridges 722 may be made of a material with a refractive index of n gi , such as silicon containing materials (e.g., SiC , S13N4, SiC, SiO x N y , or amorphous silicon), organic materials (e.g, spin on carbon (SOC) or amorphous carbon layer (ACL) or diamond like carbon (DLC)), or inorganic metal oxide layers (e.g., TiOx, AlOx, TaOx, HfOx, etc.).
- Each ridge 722 may include a leading edge 730 with a slant angel a and a trailing edge 740 with a slant angle b.
- leading edge 730 and trailing edge 740 of each ridge 722 may be parallel to each other.
- slant angle a is approximately equal to slant angle b.
- slant angle a may be different from slant angle b.
- slant angle a may be approximately equal to slant angle b.
- the difference between slant angle a and slant angle b may be less than 20%, 10%, 6%, 1%, or less.
- slant angle a and slant angle b may range from, for example, about 30° or less to about 70% or larger.
- grooves 724 between the ridges 722 may be over-coated or filled with a material having a refractive index n g 2 higher or lower than the refractive index of the material of ridges 722.
- a high refractive index material such as Hafinia, Titania, Tantalum oxide, Tungsten oxide, Zirconium oxide, Gallium sulfide, Gallium nitride, Gallium phosphide, silicon, and a high refractive index polymer, may be used to fill grooves 724.
- a low refractive index material such as silicon oxide, alumina, porous silica, or fluorinated low index monomer (or polymer), may be used to fill grooves 724.
- the difference between the refractive index of the ridges and the refractive index of the grooves may be greater than 0.1, 0.2, 0.3, 0.5, 1.0, or higher.
- the user experience with an artificial reality system may depend on several optical characteristics of the artificial reality system, such as the field of view (FOV), image quality (e.g ., resolution), size of the eye box of the system (to accommodate for eye and/or head movement), the distance of eye relief, optical bandwidth, and brightness of the displayed image.
- FOV field of view
- image quality e.g ., resolution
- size of the eye box of the system to accommodate for eye and/or head movement
- the distance of eye relief e.g ., the distance of eye relief
- optical bandwidth e.g., the distance of eye relief
- the output area of the display may be much larger than the size of the eyebox of the near-eye display system.
- the portion of light that may reach a user’s eyes may depend on the ratio between the size of the eyebox and the output area of the display, which, in some cases, may be less than 10% for a certain eye relief and field of view.
- the display light from the projector or the light source may need to be increased significantly, which may increase the power consumption and cause some safety concerns.
- FIG. 8A illustrates an example of a waveguide-based near-eye display where display light for all fields of view is substantially uniformly output from different regions of a waveguide display 810.
- the near-eye display may include a projector 820 and waveguide display 810.
- Projector 820 may be similar to projector 410 and may include a light source or image source similar to light source or image source 412 and projector optics similar to projector optics 414.
- Waveguide display 810 may include a waveguide (e.g., a substrate), one or more input couplers 812, and one or more output couplers 814.
- Input couplers 812 may be configured to couple display light from different fields of view (or viewing angles) into the waveguide, and output couplers 814 may be configured to couple display light out of the waveguide.
- the input and output couplers may include, for example, slanted surface-relief gratings or volume Bragg gratings.
- output coupler 814 may have similar grating parameters across the full region of the output coupler other than parameters that may be varied to adjust the coupling efficiency for more uniform output light.
- the display light may be partially coupled out of the waveguide at different regions of waveguide display 810 in a similar manner as shown in FIG. 8 A, where display light from all fields of view of the near-eye display may be partially coupled out of the waveguide at any given region of waveguide display 810.
- the near-eye display system may have an eyebox at a certain eyebox position 890 and having a limited size and thus a limited field of view 830.
- not all light coupled out of the waveguide in waveguide display 810 may reach the eyebox at eyebox position 890.
- display light 832, 834, and 836 from waveguide display 810 may not reach the eyebox at eyebox position 890, and thus may not be received by the user’s eyes, which may result in significant loss of the optical power from projector 820.
- an optical coupler for a waveguide-based display may include a grating coupler that includes multiple regions (or multiple multiplexed grating), where different regions of the grating coupler may have different angular selectivity characteristics (e.g., constructive interference conditions) for the incident display light such that, at any region of the waveguide-based display, diffraction light that would not eventually reach user’s eyes may be suppressed (i.e., may not be diffracted by the grating coupler so as to be coupled into or out of the waveguide and thus may continue to propagate within the waveguide), while light that may eventually reach the user’s eyes may be diffracted by the grating coupler and be coupled into or out of the waveguide.
- a grating coupler that includes multiple regions (or multiple multiplexed grating), where different regions of the grating coupler may have different angular selectivity characteristics (e.g., constructive interference conditions) for the incident display light such that, at any region of the waveguide-based display, d
- FIG. 8B illustrates an example of a waveguide-based near-eye display where display light may be coupled out of a waveguide display 840 at different angles in different regions of the waveguide display according to certain embodiments.
- Waveguide display 840 may include a waveguide (e.g., a substrate), one or more input couplers 842, and one or more output couplers 844.
- Input couplers 842 may be configured to couple display light from different fields of view (e.g., viewing angles) into the waveguide, and output couplers 844 may be configured to couple display light out of the waveguide.
- the input and output couplers may include, for example, slanted surface-relief gratings or other types of gratings or reflectors.
- the output couplers may have different grating parameters and thus different angular selectivity characteristics at different regions of the output couplers. Thus, at each region of the output couplers, only display light that would propagate in a certain angular range towards the eyebox at eyebox position 890 of the near-eye display may be coupled out of the waveguide, while other display light may not meet the angular selectivity condition at the region and thus may not be coupled out of the waveguide.
- the input couplers may also have different grating parameters and thus different angular selectivity characteristics at different regions of the input couplers, and thus, at each region of an input coupler, only display light from a respective field of view may be coupled into the waveguide. As a result, most of the display light coupled into the waveguide and propagating in the waveguide can be efficiently sent to the eyebox, thus improving the power efficiency of the waveguide-based near-eye display system.
- the refractive index modulation of a slanted surface-relief grating, and other parameters of the slanted surface-relief grating, such as the grating period, the slant angle, the duty cycle, the depth, and the like, may be configured to selectively diffract incident light within a certain incident angular range (e.g., FOV) and/or a certain wavelength band at certain diffraction directions (e.g., within an angular range shown by field of view 830).
- a certain incident angular range e.g., FOV
- a certain wavelength band e.g., within an angular range shown by field of view 830.
- a large angular bandwidth e.g., > 10°
- the output couplers may be achieved at the output couplers to provide a sufficiently large eyebox for the waveguide-based near-eye display system.
- FIG. 9A illustrates an example of a slanted grating 900 with variable etch depths according to certain embodiments.
- Slanted grating 900 may include a substrate 910 (e.g., a glass substrate) and a grating layer 920 (e.g., a dielectric or polymer layer) formed on substrate 910.
- a plurality of grating grooves 922 may be etched or otherwise formed (e.g., imprinted) in grating layer 920.
- Grating grooves 922 may have non-uniform depths, widths, and/or separations.
- slanted grating 900 may have variable grating periods, depths, and/or duty cycles.
- FIG. 9B illustrates an example of a slanted grating 905 with variable etch depths and duty cycles according to certain embodiments.
- slanted grating 905 may be etched in a dielectric layer 930, which may have a refractive index, for example, between about 1.46 and about 2.4.
- slanted grating 905 may have different etch depths and duty cycles at different regions.
- the grating period may also be different at the different regions.
- different regions of slanted grating 905 may have different desire diffraction characteristics as described above with respect to, for example, FIG. 8B.
- the surface-relief gratings with parameters and configurations (e.g., duty cycles, depths, or refractive index modulations) varying over the regions of the gratings described above and other surface-relief gratings (e.g., gratings used for eye-tracking) may be fabricated using many different nanofabrication techniques.
- the nanofabrication techniques generally include a patterning process and a post-patterning (e.g., over-coating) process.
- the patterning process may be used to form slanted ridges or grooves of the slanted grating.
- the slanted grating may be fabricated using lithography techniques including slanted etching.
- the slanted grating may be fabricated using nanoimprint lithography (NIL) molding techniques, where a master mold including slanted structures may be fabricated using, for example, slanted etching techniques, and may then be used to mold slanted gratings or different generations of soft stamps for nanoimprinting.
- the post-patterning process may be used to over-coat the slanted ridges and/or to fill the gaps between the slanted ridges with a material having a different refractive index than the slanted ridges.
- the post-patterning process (e.g., overcoating and planarization) may be independent from the patterning process.
- a same post-patterning process may be used on slanted gratings fabricated using any patterning technique.
- a substrate e.g., a waveguide
- the NIL resin layer may include, for example, a butyl-acrylate-based resin doped with a sol-gel precursor (e.g., titanium butoxide), a monomer containing a reactive functional group for subsequent infusion processes (such as acrylic acid), and/or high refractive index nanoparticles (e.g., titanium oxide, zirconium oxide, hafnium oxide, tungsten oxide, zinc tellurium, or gallium phosphide).
- a sol-gel precursor e.g., titanium butoxide
- a monomer containing a reactive functional group for subsequent infusion processes such as acrylic acid
- high refractive index nanoparticles e.g., titanium oxide, zirconium oxide, hafnium oxide, tungsten oxide, zinc tellurium, or gallium phosphide.
- the NIL resin layer may include polydimethylsiloxane (PDMS) or another silicone elastomer or silicon-based organic polymer.
- the NIL resin layer may be deposited on the substrate by, for example, spin coating, lamination, or inkjet printing.
- a NIL mold with a nanostructure formed thereon may be pressed against the NIL resin layer and the substrate for molding a nanostructure in the NIL resin layer.
- the NIL resin layer may be cured subsequently (e.g., crosslinked) using heat and/or ultraviolet (UV) light. After the curing, the NIL mold may be detached from the NIL resin layer and the substrate.
- a nanostructure e.g., a slanted grating
- a nanostructure that is complementary to the nanostructure in the NIL mold may be formed in the NIL resin layer on the substrate.
- a master NIL mold e.g., a hard mold including a rigid material, such as Si, SiCh, S13N4, or a metal
- a soft stamp may be fabricated using the master NIL mold, and the soft stamp may then be used as the working stamp to fabricate the slanted grating or may be used to fabricate a next generation soft stamp.
- the slanted grating structure in the master NIL mold may be similar to the slanted grating of the grating coupler for the waveguide display, and the slanted grating structure on the soft stamp may be complementary to the slanted grating structure in the master NIL mold and the slanted grating of the grating coupler for the waveguide display.
- a soft stamp may offer more flexibility during the molding and demolding processes.
- FIGS. 10A-10D illustrate an example of a process 1000 for fabricating a soft stamp for nanoimprinting according to certain embodiments.
- FIG. 10A shows a master mold 1010 (e.g., a hard mold or hard stamp).
- Master mold 1010 may include a rigid material, such as a semiconductor substrate (e.g., Si or GaAs), an oxide (e.g., SiCh, S13N4, TiOx, AlOx, TaOx, or HfOx), or a metal plate.
- Master mold 1010 may be fabricated using , for example, a slanted etching process using reactive ion beams or chemically assisted reactive ion beams, a micromachining process, or a 3-D printing process.
- master mold 1010 may include a slanted grating 1020 that may in turn include a plurality of slanted ridges 1022 with gaps 1024 (referred to as grooves) between slanted ridges 1022.
- FIG. 10B illustrates master mold 1010 coated with a soft stamp material layer 1030.
- Soft stamp material layer 1030 may include, for example, a resin material or a curable polymer material.
- soft stamp material layer 1030 may include polydimethylsiloxane (PDMS) or another silicone elastomer, or a silicon-based organic polymer.
- soft stamp material layer 1030 may include ethylene tetrafluoroethylene (ETFE), perfluoropoly ether (PFPE), or other fluorinated polymer or acrylic polymer materials.
- soft stamp material layer 1030 may be coated on master mold 1010 by, for example, spin-coating or inkjet printing.
- FIG. IOC illustrates a lamination process for laminating a soft stamp foil 1040 onto soft stamp material layer 1030.
- a roller 1050 may be used to press soft stamp foil 1040 against soft stamp material layer 1030.
- the lamination process may also be a planarization process to make the thickness of soft stamp material layer 1030 substantially uniform. After the lamination process, soft stamp foil 1040 may be tightly or securely attached to soft stamp material layer 1030.
- FIG. 10D illustrates a delamination process, where a soft stamp including soft stamp foil 1040 and attached soft stamp material layer 1030 is detached from master mold 1010.
- Soft stamp material layer 1030 may include a slanted grating structure that is complementary to the slanted grating structure on master mold 1010. Because the flexibility of soft stamp foil 1040 and attached soft stamp material layer 1030, the delamination process may be relatively easy compared with a demolding process using a hard stamp or mold.
- a roller e.g., roller 1050
- roller 1050 may be used in the delamination process to ensure a constant or controlled delamination speed. In some embodiments, roller 1050 may not be used during the delamination.
- an anti-sticking layer may be formed on master mold 1010 before soft stamp material layer 1030 is coated on master mold 1010.
- the anti-sticking layer may facilitate the delamination process. After the delamination of the soft stamp from master mold 1010, the soft stamp may be used to mold the slanted grating on a waveguide of a waveguide display.
- FIGS. 11A-11D illustrate an example of an imprinting process 1100 using a soft stamp according to certain embodiments.
- FIG. 11A shows a waveguide 1110 coated with an imprint resin layer 1120.
- Imprint resin layer 1120 may include, for example, a butyl-acrylate based resin doped with a sol-gel precursor (e.g., titanium butoxide), a monomer containing a reactive functional group for subsequent infusion processes (such as acrylic acid), and/or high refractive index nanoparticles (e.g., TiC , NbOx, ZrCh, GaP, HfCh, WO3, GaAs, etc.).
- a sol-gel precursor e.g., titanium butoxide
- a monomer containing a reactive functional group for subsequent infusion processes such as acrylic acid
- high refractive index nanoparticles e.g., TiC , NbOx, ZrCh, GaP, HfCh, WO3, GaAs, etc.
- imprint resin layer 1120 may include polydimethylsiloxane (PDMS) or another silicone elastomer, or silicon-based organic polymer.
- imprint resin layer 1120 may include ethylene tetrafluoroethylene (ETFE), perfluoropoly ether (PFPE), or other fluorinated polymer or acrylic polymer materials.
- Imprint resin layer 1120 may be deposited on waveguide 1110 by, for example, spin-coating, lamination, or inkjet printing.
- a soft stamp 1130 including slanted ridges 1132 attached to a soft stamp foil 1140 may be used for the imprint.
- FIG. 11B shows the lamination of soft stamp 1130 onto imprint resin layer 1120.
- Soft stamp 1130 may be pressed against imprint resin layer 1120 and waveguide 1110 using a roller 1150, such that slanted ridges 1132 may be pressed into imprint resin layer 1120.
- Imprint resin layer 1120 may be cured subsequently.
- imprint resin layer 1120 may be crosslinked using heat and/or ultraviolet (UV) light.
- UV ultraviolet
- FIG. llC shows the delamination of soft stamp 1130 from imprint resin layer 1120.
- the delamination may be performed by lifting soft stamp foil 1140 to detach slanted ridges 1132 of soft stamp 1130 from imprint resin layer 1120.
- Imprint resin layer 1120 may now include a slanted grating 1122, which may be used as the grating coupler or may be over coated to form the grating coupler for the waveguide display.
- a roller e.g., roller 1150
- roller 1150 may be used in the delamination process to ensure a constant or controlled delamination speed.
- roller 1150 may not be used during the delamination.
- FIG. 11D shows an example imprinted slanted grating 1122 formed on waveguide 1110 using soft stamp 1130.
- slanted grating 1122 may include ridges and grooves between the ridges and thus may be over-coated with a material having a refractive index different from imprint resin layer 1120 to fill the grooves and form the grating coupler for the waveguide display.
- the period of the slanted grating may vary from one area to another on slanted grating 1122, or may vary from one period to another (i.e., chirped) on slanted grating 1122.
- Slanted grating 1122 may have a duty cycle ranging, for example, from about 11% to about 100% or greater. In some embodiments, the duty cycle may vary from period to period. In some embodiments, the depth of the grooves or height of the ridges of slanted grating 1122 may be greater than about 50 nm, about 110 nm, about 200 nm, about 300 nm, about 400 nm, or higher.
- the slant angles of the leading edges of the ridges of slanted grating 1122 and the slant angles of the trailing edges of the ridges of slanted grating 1122 may be greater than about 30°, about 45°, about 60°, or higher.
- the leading edge and training edge of each ridge of slanted grating 1122 may be parallel to each other.
- the difference between the slant angle of the leading edge of a ridge of slanted grating 1122 and the slant angle of the trailing edge of the ridge of slanted grating 1122 may be less than about 20%, about 11%, about 5%, about 1%, or less.
- a master mold (which may be referred to as a generation 0 mold) may be fabricated (e.g., etched) in, for example, a semiconductor substrate, a quartz, or a metal plate.
- the master mold may be a hard stamp and may be used as the working stamp to mold the slanted grating directly, which may be referred to as hard stamp NIL or hard NIL.
- the slanted structure on the mold may be complimentary to the desired slanted structure of the slanted grating used as the grating coupler on a waveguide display.
- the master NIL mold may be fabricated first, and a hybrid stamp (which may be referred to as generation 1 mold or stamp) may then be fabricated using the master NIL mold.
- the hybrid stamp may be used as the working stamp for nanoimprinting.
- the hybrid stamp may include a hard stamp, a soft stamp, or a hard-soft stamp. Nanoimprinting using a soft stamp may be referred to as soft stamp NIL or soft NIL.
- the hybrid mold may include a plastic backplane with soft or hard patterned polymer (e.g., having a Young’s modulus about 1 GPa).
- the hybrid mold may include a glass backplane with soft or hard patterned polymer (e.g., having a Young’s modulus about 1 GPa). In some embodiments, the hybrid mold may include a glass/plastic laminated backplane with soft or hard patterned polymer. In some embodiments, a generation 2 hybrid mold may be made from the generation 1 mold, and may then be used as the working stamp for the nanoimprinting. In some embodiments, generation 3 hybrid molds, generation 4 hybrid molds, and the like, may be made and used as the working stamp. NIL molding may significantly reduce the cost of making the slanted surface-relief structures because the molding process may be much faster than the etching process and no expensive reactive ion etching equipment may be needed.
- FIGS. 12A-12C illustrate an example of a method of forming a planarized overcoat layer on a surface-relief grating using an imprint process according to certain embodiments.
- FIG. 12A shows that an overcoat material as described above may be dispensed on a surface- relief grating 1220 on a substrate 1210 to form an overcoat layer 1230.
- the overcoat material may be dispensed by, for example, by spin-coating or inkjet printing.
- the amount of overcoat material dispensed on surface-relief grating 1220 may be determined based on the dimensions of the grating grooves and the desired thickness of the overburden (e.g., the portion of the overcoat layer on top of the grating ridges).
- the overburden thickness is less than about 20 nm.
- the top surface of overcoat layer 1230 may not be flat as shown in the illustrated example.
- the height of the top surface at the grating ridge regions may be greater than the height of the top surface at the grating groove regions.
- the overcoat layer may optionally be baked to remove the solvent from the overcoat layer.
- Air trapping e.g., air bubbles
- the solvent in the overcoat material may have not completely evaporated.
- the solvent and/or trapped air may result in a varying refractive index of the overcoat layer and an efficiency loss.
- the problems may be exacerbated when the grating grooves are relatively deep (e.g., 120 nm, 200 nm, 300 nm, or greater), when the grating grooves are relatively narrow (e.g., gratings with large duty cycles), and/or when the slant angles of the grating ridges are relatively large, such as greater than about 30°, 45°, 50°, 70°, or larger. Baking may help to remove the solvent and the trapped air such that the overcoat material in the overcoat layer may be more uniform or homogeneous.
- FIG. 12B shows that a planar imprint stamp 1240 (e.g., a soft stamp or mold described above) may be laminated or otherwise applied on overcoat layer 1230 in an imprint process.
- planar imprint stamp 1240 may include polydimethylsiloxane (PDMS) or another silicone elastomer or silicon-based organic polymer.
- planar imprint stamp 1240 may include ethylene tetrafluoroethylene (ETFE), perfluoropoly ether (PFPE), or other fluorinated polymer or acrylic polymer materials.
- ETFE ethylene tetrafluoroethylene
- PFPE perfluoropoly ether
- the bottom surface of planar imprint stamp 1240 that contacts overcoat layer 1230 may have a low surface roughness.
- Planar imprint stamp 1240 may be pressed against overcoat layer 1230, for example, using a roller as described above with respect to, for example, FIG. 12B. Thus, some portions of the overcoat materials on top of the grating ridges may be forced to the regions on top of the grating grooves, and the flat bottom surface of planar imprint stamp 1240 may be transferred to the top surface of overcoat layer 1230.
- the overcoat layer may then be cured (e.g., using UV light) to crosslink and fix the base resin in the overcoat material as described above.
- the planar imprint stamp may be delaminated or otherwise detached from the overcoat layer and the surface-relief grating, as described above with respect to, for example, FIG. 12C.
- FIG. 12C shows that, after the delamination of planar imprint stamp 1240, the top surface of overcoat layer 1230 can be flat and smooth.
- the overburden can be very thin, such as less than about 20 nm.
- FIGS. 13A-13B illustrate an example of a method of forming a planarized overcoat layer on a surface-relief grating 1300 having variable grating parameters according to certain embodiments.
- FIG. 13A shows surface-relief grating 1300 including grating ridges 1320 on a substrate 1310 (or a grating material layer or waveguide), where the duty cycle and slant angle of surface-relief grating 1300 may vary from region to region.
- Inkjet printing or 3-D printing techniques may be used to dispense different amounts of overcoat material 1330 in different regions of surface-relief grating 1300.
- a larger number of small drops of overcoat material 1330 may be dispensed in regions where the dimensions of the grating grooves are larger, and a smaller number of small drops of overcoat material 1330 may be deposited in regions where the dimensions of the grating grooves are smaller.
- the amount of overcoat material dispensed may be more precisely controlled by dispensing small drops of overcoat material 1330.
- FIG. 13B shows that a planar imprint stamp 1340 may be laminated or otherwise applied on overcoat material 1330, for example, after an optional baking process to remove solvent and/or trapped air.
- Planar imprint stamp 1340 may be pressed against overcoat material 1330, for example, using a roller as described above with respect to, for example, FIG. IOC.
- some portions of the overcoat material 1330 on top of grating ridges 1320 may be forced to the regions on top of the grating grooves, and the flat bottom surface of planar imprint stamp 1340 may be transferred to the top surface of the overcoat layer formed by overcoat material 1330.
- Overcoat material 1330 may then be cured (e.g., using UV light) to crosslink and fix the base resin as described above.
- planar imprint stamp 1340 may be delaminated or otherwise detached from the overcoat material layer and the surface-relief grating, as described above with respect to, for example, FIG. IOC. In this way, the top surface of the overcoat layer may be flat. Because the amount of overcoat material dispensed can be more precisely controlled, the thickness of the overburden can be more precisely controlled, and can be very thin, such as less than about 20 nm, less than about 10 nm, or less.
- the grating ridges may be formed in a high-refractive index material layer (e.g., including a resin with high-refractive index nanoparticles) using nanoimprinting techniques described above with respect to, for example, FIGS. 10A-11D, and an overcoat layer with a low refractive index may be used to achieve the large refractive index contrast.
- a high-refractive index material layer e.g., including a resin with high-refractive index nanoparticles
- an overcoat layer with a low refractive index may be used to achieve the large refractive index contrast.
- the grating ridges may be made of a low-refractive index material (e.g., glass), and an overcoat layer with a high refractive index (e.g., about 2.0 or larger) may be used to achieve the large refractive index contrast.
- a low-refractive index material e.g., glass
- an overcoat layer with a high refractive index e.g., about 2.0 or larger
- the high-refractive index material for the grating ridges or the overcoat layer may include a resin dispersed with high- refractive index nanoparticles, such as TiCh nanoparticles, ZrCh nanoparticles, NbOx nanoparticles, and the like, or may include a sol-gel material that includes a solution and a high-refractive index oxide precursor (e.g., Ti precursor) and has been partially or fully condensed into an extended network.
- a resin dispersed with high- refractive index nanoparticles such as TiCh nanoparticles, ZrCh nanoparticles, NbOx nanoparticles, and the like
- a sol-gel material that includes a solution and a high-refractive index oxide precursor (e.g., Ti precursor) and has been partially or fully condensed into an extended network.
- TiCh has a higher refractive index (e.g., greater than 2.5 for visible light) than ZrCh (e.g., about 2.15 for visible light) and some other materials (e.g., metal oxides such as NbOx, LaOx, TaOx, AI2O3, etc.), and thus may be mixed with a resin material to form a high refractive index resin (e.g., with a refractive index about 2.0 or higher) for nanoimprinting or overcoating. For example, a 200-nm-thick resin layer including 90 wt.
- a high refractive index resin e.g., with a refractive index about 2.0 or higher
- a 200-nm-thick resin layer including 90 wt.
- % of ZrCh nanoparticles may have a refractive index about 1.78 for 520-nm light, while a 200-nm-thick resin layer including 90 wt. % of TiCh nanoparticles may have a refractive index about 2.05 for 520-nm light.
- TiCh may absorb UV light (e.g., with a wavelength l ⁇ 388 nm) to excite electrons (e ) to the conduction band and leave holes (h + ) in the valence band. The electrons and holes may migrate to the surface of the nanoparticles to reduce and/or oxidize reactants adjacent to the nanoparticles.
- FIG. 14A illustrates an example of the photocatalytic activity of TiCh nanoparticles.
- electrons in TiCh particles may be excited to the conduction band, to generate free electrons and holes. Some free electrons and holes may recombine within a short time period to release energy in the form of heat or photons. Some electrons and holes may migrate to the surfaces of the TiCh nanoparticles.
- the photo- produced holes may generate hydroxyl radicals ⁇ OH by the oxidation of OH and/or H2O molecules that may be absorbed onto the surfaces of TiCh nanoparticles.
- the photo-produced electrons may facilitate the reduction of O2 molecules absorbed onto the surfaces of TiCh nanoparticles to form superoxide radical anions « 0 ⁇ .
- These photo-generated hydroxyl radicals and superoxide radicals may in turn oxidize and degrade adjacent organic and/or inorganic materials.
- These reduction and oxidation reactions shown in FIG. 14A may be used in photocatalytic hydrogen production and photocatalytic water/air purification, respectively.
- Other metal oxides, such as NbOx, which may have a refractive index between about 2.3 and about 2.35, may also be photoactive.
- FIG. 14B illustrates an example of organic degradation caused by the photocatalytic activity of TiCh nanoparticles 1410.
- TiCh nanoparticles 1410 may interact with moisture (H2O) and/or oxygen (O2) to generate radicals (e.g., hydroxyl radicals and superoxide radical anions).
- the hydroxyl radicals may oxidize and degrade organics 1420 (e.g., ligands and resin) adjacent to TiCh nanoparticles 1410. These interaction may be triggered via titanium oxide photoexcitation and/or may be thermally induced.
- TiCh nanoparticles 1410 due to their high surface-volume ratios, may have high light absorption rate, which may increase the surface photo-induced carrier density that can lead to higher surface photoactivity and enhanced photocatalytic activity of TiCh nanoparticles.
- more organics 1420 may be oxidized and degraded to absorb visible light. Therefore, a film including titanium oxide nanoparticles 1410 and organics 1420 may show some levels of light absorption in the visible spectrum even though TiCh nanoparticles 1410 are transparent to visible light.
- the absorption of visible light by the film including titanium oxide nanoparticles and organics may increase over time, as the film undergoes further redox interactions with the environment, such as upon further exposure to UV and heat. Therefore, surface-relief gratings or overcoat layers made (e.g., imprinted) using films including titanium oxide nanoparticles and organics may lead to high absorption and low throughput for waveguide displays.
- FIGS. 15A-15D illustrate an example of a process of fabricating a surface-relief grating that includes overcoat layers with metal oxide nanoparticles and organics.
- FIG. 15A illustrates an example of a substrate 1510 including one or more surface-relief gratings 1512 formed in or on substrate 1510.
- surface-relief gratings 1512 may be fabricated by etching substrate 1510 using wet or dry etching techniques, such as ion beam etching.
- surface-relief gratings 1512 may be fabricated by depositing a nanoimprint resin layer and imprinting the nanoimprint resin layer using a mold or a soft stamp as described above.
- the nanoimprint resin layer may include high-refractive index metal oxide nanoparticles (e.g., TiC nanoparticles, NbOx nanoparticles, and/or ZrCh nanoparticles) dispersed in a resin.
- the resin may include, for example, acrylate resin with photo radical generator or thermal radical generator.
- the refractive index of the acrylate resin may be between about 1.55 and about 1.7.
- the resin may include difunctional high-refractive index monomers, such as Ml from TOKYO OHKA KOGYO CO., LTD. (TOK).
- FIG. 15B illustrates an example of a first overcoat layer 1520 formed on a surface- relief grating 1512 on one side of substrate 1510.
- first overcoat layer 1520 may be formed on surface-relief grating 1512 using techniques disclosed above with respect to, for example, FIGS. 12A-13B.
- first overcoat layer 1520 may be a nanoimprint resin layer that includes high-refractive index metal oxide nanoparticles (e.g., TiCh nanoparticles, NbOx nanoparticles, and/or ZrCh nanoparticles) dispersed in a resin.
- the resin may include, for example, acrylate resin with photo radical generator or thermal radical generator.
- the refractive index of the acrylate resin may be between about 1.55 and about 1.7.
- the resin may include difunctional high- refractive index monomers, such as Ml from TOK.
- First overcoat layer 1520 may be deposited on surface-relief grating 1512, baked at an elevated temperature (e.g., about 90 °C), and cured using UV light 1505.
- the nanoimprint resin layer may be imprinted using a flat stamp as described above with respect to, for example, FIGS. 12A-13B.
- Curing first overcoat layer 1520 using UV light may degrade the organics in first overcoat layer 1520 due to the photocatalytic activity of the metal oxide (e.g., TiCh or NbOx) nanoparticles, as described above with respect to, for example, FIGS. 14A and 14B.
- the metal oxide e.g., TiCh or NbOx
- FIG. 15C shows that a second overcoat layer 1530 may be formed on a surface- relief grating 1512 on a second side of substrate 1510.
- Second overcoat layer 1530 may be formed on surface-relief grating 1512 using techniques disclosed above with respect to, for example, FIGS. 12A-13B.
- second overcoat layer 1530 may be a nanoimprint resin layer that includes high-refractive index metal oxide nanoparticles dispersed in a resin as described above with respect to first overcoat layer 1520, where second overcoat layer 1530 may be deposited on surface-relief grating 1512, baked at an elevated temperature (e.g., about 90 °C), and then cured using UV light 1505.
- an elevated temperature e.g., about 90 °C
- the nanoimprint resin layer may be imprinted using a flat stamp, as described above with respect to, for example, FIGS. 12A-13B and 15B.
- Curing second overcoat layer 1530 using UV light 1505 may degrade the organics in second overcoat layer 1530 due to the photocatalytic activity of the metal oxide (e.g., TiCh or NbOx) nanoparticles.
- Curing second overcoat layer 1530 using UV light 1505 may further expose first overcoat layer 1520 to UV light 1505, and thus may further degrade the organics in first overcoat layer 1520 due to the photocatalytic activity of the metal oxide (e.g., TiCh or NbOx) nanoparticles exposed to UV light.
- FIG. 15D shows that antireflective coating layers 1540 may be coated on first overcoat layer 1520 and second overcoat layer 1530 to form a waveguide display 1500.
- Antireflective coating layers 1540 may be used to reduce Fresnel reflection at the interfaces between waveguide display 1500 and air.
- antireflective coating layers 1540 may be baked and cured using UV light 1505. Curing antireflective coating layers 1540 using UV light 1505 may further expose first overcoat layer 1520 and second overcoat layer 1530 to UV light 1505, and thus may further degrade the organics in first overcoat layer 1520 and second overcoat layer 1530 due to the photocatalytic activity of the metal oxide (e.g., TiCh or NbOx) nanoparticles.
- the metal oxide e.g., TiCh or NbOx
- FIG. 15E illustrates changes in the optical losses of examples of waveguide displays including surface-relief gratings having different metal oxide nanoparticles and organics during the fabrication processes.
- the metal oxide nanoparticles may be photocatalysts that can cause photoactivities upon exposure to light of certain wavelengths.
- the bandgap energy of TiCh may be about 3.0 eV to about 3.2 eV, and may absorb UV light (e.g., with a wavelength l ⁇ 388 nm) to generate free electron-hole pairs that may in turn generate radicals that can react with and degrade adjacent organic or inorganic materials to reduce the transmissivity of the waveguide display.
- the bandgap energy of ZrCh may be about 5.0 eV, much higher than that of TiCh, and thus may only absorb deep UV light. Therefore, a resin layer including ZrCh nanoparticles may have a lower level of degradation of the organic materials after UV curing and thermal processing, and thus may have a lower optical loss for visible light.
- first overcoat layer 1520 and second overcoat layer 1530 may be a mixture including Ml from TOK, ZrCh nanoparticles, and a solvent, where the ZrCh nanoparticles may be about 90 wt. % of the mixture, and the refractive index of first overcoat layer 1520 and second overcoat layer 1530 may be about 1.78.
- a bar 1552 in FIG. 15E shows the optical loss of an example of the structure shown in FIG. 15B after first overcoat layer 1520 is baked at 90 °C and before first overcoat layer 1520 is cured using UV light, where first overcoat layer 1520 may include ZrCh nanoparticles and the thickness of first overcoat layer 1520 may be about 140 nm.
- a bar 1554 shows the optical loss of the example of the structure shown in FIG. 15B after first overcoat layer 1520 is cured using UV light.
- a bar 1556 shows the optical loss of an example of the structure shown in FIG. 15C after second overcoat layer 1530 is baked at 90 °C and is cured using UV light, where second overcoat layer 1530 may include ZrCh nanoparticles and the thickness of second overcoat layer 1530 may be about 140 nm.
- a bar 1558 shows the optical loss of waveguide display 1500 shown in FIG. 15D after antireflective coating layers 1540 are baked at 90 °C and are cured using UV light.
- the optical losses of the overcoat layers including organics and include ZrCh nanoparticles may increase slightly during the fabrication processes.
- first overcoat layer 1520 and second overcoat layer 1530 may be a mixture including Ml from TOK, TiCh nanoparticles, and a solvent, where the TiCh nanoparticles may be about 90 wt. % of the mixture, and the refractive index of first overcoat layer 1520 and second overcoat layer 1530 may be about 2.05.
- a bar 1562 in FIG. 15E shows the optical loss of an example of the structure shown in FIG. 15B after first overcoat layer 1520 is baked at 90 °C and before first overcoat layer 1520 is cured using UV light, where first overcoat layer 1520 may include TiCh nanoparticles and the thickness of first overcoat layer 1520 may be about 140 nm.
- a bar 1564 shows the optical loss of the example of the structure shown in FIG. 15B after first overcoat layer 1520 is cured using UV light.
- a bar 1566 shows the optical loss of an example of the structure shown in FIG. 15C after second overcoat layer 1530 is baked at 90 °C and is cured using UV light, where second overcoat layer 1530 may include TiCh nanoparticles and the thickness of second overcoat layer 1530 may be about 140 nm.
- a bar 1568 shows the optical loss of an example of waveguide display 1500 shown in FIG. 15D after antireflective coating layers 1540 are baked at 90 °C and are cured using UV light.
- first overcoat layer 1520 and second overcoat layer 1530 may increase significantly during the fabrication processes, and can be very high when TiCh nanoparticles are used in the overcoat layers. Thus, it can be difficult to achieve both a high refractive index and a low optical loss for an overcoat layer.
- organics in an imprinted grating layer or an overcoat layer such as organic ligands on metal oxide (e.g., TiCh or NbCh) nanoparticles that may have been degraded (oxidized) or may not have been degraded, may be removed and/or replaced with another material, such as an inorganic material (e.g., Si-containing material) or another organic material that may have a low optical loss and may not be degraded by the photocatalytic activity of the metal oxide nanoparticles.
- metal oxide e.g., TiCh or NbCh
- another material such as an inorganic material (e.g., Si-containing material) or another organic material that may have a low optical loss and may not be degraded by the photocatalytic activity of the metal oxide nanoparticles.
- the organic ligands on metal oxide nanoparticles in a grating layer or an overcoat layer may be removed (e.g., burned) by a high-energy treatment process, such as rapid thermal annealing (RTA) or laser spike annealing (LSA), to form porous structures in the grating layer or the overcoat layer.
- a high-energy treatment process such as rapid thermal annealing (RTA) or laser spike annealing (LSA)
- An organic or inorganic material layer (e.g., an overcoat layer or an antireflective coating layer) may then be formed on the grating layer or the overcoat layer to fill the porous structures in the grating layer or the overcoat layer, thereby increasing the refractive index while reducing the absorption loss of the grating layer or the overcoat layer.
- the imprinted surface-relief grating or the overcoat layer of the surface-relief grating may be characterized by a first refractive index greater than 2.0 for visible light and an absorption lower than 0.05% for visible light.
- a method may include depositing a nanoimprint material layer (including nanoparticles dispersed in a resin material) on a substrate, imprinting a surface-relief grating in the nanoimprint material layer using a stamp, curing the nanoimprint material layer by heat or electromagnetic radiation, delaminating the stamp, performing an RTA process or an LSA process on the imprinted surface-relief grating to remove light-absorbing organics and form porous structures in the imprinted surface-relief grating, and depositing an overcoat layer that includes an organic material, an inorganic material, or a combination thereof on the imprinted surface-relief grating to fill the porous structures in the imprinted surface-relief grating and increase the refractive index of the grating ridges of the imprinted surface-relief grating.
- a method may include depositing an overcoat layer including a sol-gel material or nanoparticles dispersed in a resin material on a surface- relief grating to at least partially fill grating grooves of the surface-relief grating, optionally imprinting the overcoat layer using a planar imprint stamp, curing the overcoat layer by heat or electromagnetic radiation, performing an RTA process or an LSA process on the overcoat layer to remove light-absorbing organics and form porous structures in the overcoat layer, and depositing an antireflective coating layer that may include an organic material, an inorganic material, or a combination thereof on the overcoat layer to fill the porous structures in the overcoat layer and increase the refractive index of the overcoat layer.
- the nanoimprint material layer or the overcoat layer may include nanoparticle-based formulation or sol-gel-based formulation.
- the nanoparticle-based formulation may include acrylate resin (with a refractive index between about 1.55 and about 1.7) with photo radical generator or thermal radical generator, 75%-90% TiOx, ZrOx, and/or NbOx nanoparticles with acrylate and non-functional decoration ligands, and a solvent.
- the solvent may include, for example, propylene glycol methyl ether acetate (PGMEA) (for spin coating) or dipropylene glycol methyl ether (DPGME)/ tripropylene glycol monomethyl ether (TPM) for inkjet coating.
- PGMEA propylene glycol methyl ether acetate
- DPGME dipropylene glycol methyl ether
- TPM tripropylene glycol monomethyl ether
- the solvent may include a solvent blend including one or more solvents that may or may not have boiling points greater than 200°C.
- the sol-gel-based formulation may include EMD MHM-63, Philips high refractive index sol-gel formulation, or organic solvent- soluble Titania with ligands in a solvent, such as PGMEA or DPGME/TPM.
- the organic and/or inorganic material that back-fills the porous structures in the imprinted surface-relief grating or the overcoat layer may have low optical loss, and may include, for example, organic materials such as acrylate, polystyrenics, epoxy based organic materials, siloxane based materials, inorganic materials such as AI2O3, S1O2, ZrCh, M>2q5, TiCh, Ta20s, and the like, or a combination of organic materials and inorganic materials describe above.
- organic materials such as acrylate, polystyrenics, epoxy based organic materials, siloxane based materials, inorganic materials such as AI2O3, S1O2, ZrCh, M>2q5, TiCh, Ta20s, and the like, or a combination of organic materials and inorganic materials describe above.
- depositing the first layer of the organic material, the inorganic material, or a combination thereof on the imprinted surface-relief grating or the overcoat layer may include an inkjet coating process, a spin coating process, an atomic layer deposition (ALD) process, a physical vapor deposition (PVD) process, an initiated chemical vapor deposition (iCVD) process, or a combination thereof.
- ALD atomic layer deposition
- PVD physical vapor deposition
- iCVD initiated chemical vapor deposition
- the ALD process may use ALD precursors such as TiCU and H2O, tetrakis (dimethylamino) titanium(IV) (TDMAT) and O3, tetrakis (dimethylamido) zirconium (IV) (TDMAZ) / trimethylaluminum (TMA) and H2O, or the like.
- ALD precursors such as TiCU and H2O, tetrakis (dimethylamino) titanium(IV) (TDMAT) and O3, tetrakis (dimethylamido) zirconium (IV) (TDMAZ) / trimethylaluminum (TMA) and H2O, or the like.
- FIGS. 16A-16E illustrate an example of a process of fabricating a surface-relief grating including a high-refractive index and low-loss overcoat layer according to certain embodiments.
- FIG. 16A illustrates an example of a substrate 1610 including one or more surface-relief gratings 1612 formed in or on substrate 1610.
- Surface-relief gratings 1612 may be fabricated by etching substrate 1610 using wet or dry etching techniques, such as ion beam etching, or may be fabricated by depositing a nanoimprint resin layer and imprinting the nanoimprint resin layer using a mold or a soft stamp as described above.
- FIG. 16B illustrates an example of a first overcoat layer 1620 formed on a surface- relief grating 1612 on one side of substrate 1610.
- first overcoat layer 1620 may be a nanoimprint resin layer that includes high-refractive index metal oxide nanoparticles (e.g., T1O2 nanoparticles, NbOx nanoparticles, and/or ZrCh nanoparticles) dispersed in a resin and a solvent.
- the resin may include, for example, acrylate resin with photo radical generator or thermal radical generator.
- the refractive index of the acrylate resin may be between about 1.55 and about 1.7.
- the resin may include difunctional high-refractive index monomers, such as Ml from TOK.
- the nanoparticles may be about 75-90 wt. % of the nanoimprint resin layer, and may include TiOx, ZrOx, and/or NbOx nanoparticles with acrylate and non-functional decoration ligands.
- the solvent may include, for example, PGMEA (for spin coating) or DPGME/TPM (for inkjet coating).
- the solvent may include a solvent blend with one or more solvents that may or may not have boiling points greater than 200°C.
- first overcoat layer 1620 may include a sol-gel material that includes a solution and a high-refractive index oxide precursor (e.g., Ti precursor) and has been partially or fully condensed into an extended network.
- the sol-gel material may include EMD MHM-63, Philips high refractive index sol-gel formulation, or organic solvent-soluble Titania with ligands in a solvent, such as PGMEA or DPGME/TPM.
- first overcoat layer 1620 may be formed on the surface-relief grating 1612 using techniques disclosed above, for example, with respect to FIGS. 12A-13B.
- first overcoat layer 1620 may be deposited on surface-relief grating 1612, baked at an elevated temperature (e.g., about 90 °C), and cured using UV light 1605.
- the nanoimprint resin layer may be imprinted using a flat stamp as described above to form first overcoat layer 1620 with a flat top surface.
- Curing first overcoat layer 1620 using UV light may degrade the organics (e.g., ligands on the nanoparticles) in first overcoat layer 1620 due to the photocatalytic activity of the metal oxide (e.g., TiCh or NbOx) nanoparticles described above with respect to, for example, FIGS. 14A and 14B.
- the metal oxide e.g., TiCh or NbOx
- FIG. 16C shows that a second overcoat layer 1630 may be formed on a surface- relief grating 1612 on a second side of substrate 1610.
- second overcoat layer 1630 may be formed on surface-relief gratings 1612 using materials and techniques disclosed above, for example, with respect to FIGS. 12A-13B and 16B.
- second overcoat layer 1630 may be deposited on surface-relief grating 1612, baked at an elevated temperature (e.g., about 90 °C), and then cured using UV light 1605.
- the nanoimprint resin layer may be imprinted using a flat stamp to form a flat top surface on second overcoat layer 1630.
- Curing second overcoat layer 1630 using UV light may degrade the organics in second overcoat layer 1630 due to the photocatalytic activity of the metal oxide (e.g., TiCh or NbOx) nanoparticles. Curing second overcoat layer 1630 may further expose first overcoat layer 1620 to UV light 1605, and thus may further degrade the organics in first overcoat layer 1620 due to the photocatalytic activity of the metal oxide nanoparticles.
- the metal oxide e.g., TiCh or NbOx
- FIG. 16D shows that organic materials in the first overcoat layer 1620 and second overcoat layer 1630, including organics (e.g., organic ligands on nanoparticles) degraded during the fabrication processes, may be removed (e.g., burned) by a high-energy treatment process, such as rapid thermal annealing (RTA), laser spike annealing (LSA), or UV irradiation, to form porous structures 1622 and 1632 that may include metal oxide nanoparticles and pores between the metal oxide nanoparticles.
- RTA rapid thermal annealing
- LSA laser spike annealing
- UV irradiation UV irradiation
- the samples may be heated to or cooled down from a temperature between about 200 °C and about 1300 °C, with a ramp rate about 20-200 °C/sec, combined with gas ambient control.
- the short treatment may activate catalytic reactions to quickly remove the organic materials.
- the rapid heating rate can be achieved by, for example, high intensity lamps (e.g. near-infrared light sources, such as tungsten-halogen lamps) controlled by pyrometer and thermocouples that measure the sample temperature. Cooling may also be controlled to prevent dislocations and sample breakage.
- LSA processes may use a narrow laser beam to heat the sample from a low temperature to a peak annealing temperature to bum the organic materials.
- porous structures 1622 and 1632 may have lower refractive indices than first overcoat layer 1620 and second overcoat layer 1630.
- FIG. 16E shows that antireflective coating layers 1640 may be coated on first overcoat layer 1620 and second overcoat layer 1630 to form a waveguide display.
- Antireflective coating layers 1640 may be used to reduce Fresnel reflection at the interfaces between the waveguide display and air.
- antireflective coating layers 1640 may be baked and cured using UV light 1605.
- Antireflective coating layers 1640 may include organic and/or inorganic materials, and may fill the pores in porous structures 1622 and 1632 to form filled overcoat layer 1624 and filled overcoat layer 1634 that may have a higher refractive index (due to the back fill) and a lower absorption loss (due to the removal of the degraded organics and other organics that may be degraded upon exposure to UV light or heat).
- the organic and/or inorganic materials that fill the pores in porous structures 1622 and 1632 may have low optical loss, and may include, for example, organic materials such as acrylate, polystyrenics, epoxy based organic materials, siloxane based materials, inorganic materials such as AI2O3, S1O2, ZrCh, Nb20s, T1O2, Ta20s, and the like, or a combination of organic materials and inorganic materials describe above.
- depositing antireflective coating layer 1640 may include an inkjet coating process, a spin coating process, ALD process, a PVD process, an iCVD process, or a combination thereof.
- the ALD process may use ALD precursors, such as TiCL and H2O, TDMAT and O3, TDMAZ/TMA and H2O, or the like.
- FIG. 17A illustrates an example of a device 1700 including a back-filled nanoparticle layer 1720 according to certain embodiments.
- device 1700 may include a substrate 1710, back-filled nanoparticle layer 1720, and an antireflective coating layer 1730.
- Back-filled nanoparticle layer 1720 may be formed by, for example, depositing a resin layer including T1O2 nanoparticles as described above, curing the resin layer, treating the resin layer using RTA (e.g., at about 600 °C) to remove organic materials and form nanoporous structures, and depositing antireflective coating layer 1730 on the nanoporous structures such that materials (e.g., a siloxane based material) in antireflective coating layer 1730 may fill the nanoporous structures in the resin layer to form back-filled nanoparticle layer 1720 that may have a high refractive index and a low optical absorption.
- RTA e.g., at about 600 °C
- antireflective coating layer 1730 may have a thickness about 100 nm and a refractive index about 1.5, and back-filled nanoparticle layer 1720 may have a thickness about 150 nm and a refractive index about 2.02.
- the optical loss of device 1700 for visible light is measured to be about 0.13%.
- FIG. 17B illustrates an example of a surface-relief grating 1705 including a back filled high-refractive index overcoat layer 1760 according to certain embodiments.
- Surface- relief grating 1705 may include a substrate 1740, a grating layer 1750, overcoat layer 1760, and an antireflective coating layer 1770.
- Grating layer 1750 may include surface-relief structures formed therein.
- Overcoat layer 1760 may fill grooves in grating layer 1750, and may be formed by processes described above with respect to, for example, FIGS. 16A-16E.
- antireflective coating layer 1770 may have a thickness about 50 nm and may include AI2O3 with a refractive index about 1.6.
- Antireflective coating layer 1770 may be deposited using, for example, ALD or SIS processes described above.
- the deposited AI2O3 may fill nanoporous structures in overcoat layer 1760.
- the back-filled overcoat layer 1760 may have a thickness about 180 nm and a refractive index between about 2.07 and about 2.11.
- the optical loss of surface-relief grating 1705 for visible light is measured to be about 0.06%.
- FIG. 18A illustrates an X-ray photoelectron spectroscopy (XPS) profile of an example of a structure (e.g., the structure shown in FIG. 16D) including a substrate and an overcoat layer with organics removed by RTA at about 600 °C according to certain embodiments.
- the overcoat layer has a thickness about 135 nm, and is made using a resin material that includes organics and T1O2 nanoparticles as described above.
- Curves 1810, 1820, 1830, and 1840 in FIG. 18A show the atomic concentrations of carbon, oxygen, silicon, and titanium, respectively, in the substrate and the overcoat layer after the RTA.
- the carbon- based resin is removed from the overcoat layer, such that the remaining overcoat layer may include nanoporous structures formed by T1O2 nanoparticles and pores between the T1O2 nanoparticles.
- the remaining overcoat layer may have a refractive index about 1.87 and a density about 2.67 g/cm 3 as measured using x-ray reflectivity.
- FIG. 18B illustrates an XPS profile of an example of a structure (e.g., device 1700 or the structure shown in FIG. 16E) including a substrate, an overcoat layer, and a back-fill layer according to certain embodiments.
- the overcoat layer has a thickness about 135 nm, and may be made using a resin material including T1O2 nanoparticles dispersed in a carbon-based resin.
- the carbon-based resin may be removed from the overcoat layer using the high-energy treatment processes described above (e.g.,
- the overcoat layer may include nanoporous structures formed by TiCh nanoparticles and pores between the TiCh nanoparticles.
- the back-fill layer may be an antireflective coating layer, and may include, for example, a thin film including a siloxane based material and having a thickness about 100 nm.
- the siloxane based material may have a refractive index about 1.5 and a density about 1.37 g/cm 3 .
- the siloxane based material may fill the pores between the TiCh nanoparticles in the nanoporous structures. Curves 1812, 1822, 1832, 1842, and 1850 in FIG.
- the atomic concentration of carbon is greater than about 60% in the back-fill layer, and about 5% or less in the overcoat layer.
- the atomic concentration of oxygen is about 20% in the back-fill layer, and about 60% in the overcoat layer.
- the atomic concentration of silicon is about 15% in the back-fill layer, and about 5% in the overcoat layer.
- the atomic concentration of titanium is 0% in the back-fill layer, and about 30% in the overcoat layer.
- the back-filled overcoat layer may have a refractive index about 2.02 and a density about 2.99 g/cm 3 .
- FIG. 18C illustrates an XPS profile of an example of a structure including a substrate, an overcoat layer, and an AI2O3 layer formed on the overcoat layer according to certain embodiments.
- the overcoat layer has a thickness about 175 nm, and may be made using a resin material including TiCh nanoparticles dispersed in a carbon-based resin.
- the carbon-based resin may be removed from the overcoat layer using the high-energy treatment processes described above (e.g., RTA at about 600 °C), such that the overcoat layer may include nanoporous structures formed by TiCh nanoparticles and pores between the TiCh nanoparticles.
- the AhCh layer may be an antireflective coating layer, and may have a thickness about 50 nm.
- the AI2O3 layer may have a refractive index about 1.6 and a density about 2.66 g/cm 3 .
- the AI2O3 layer may be deposited on the nanoporous structures by, for example, atomic layer deposition.
- the aluminum atoms in the AI2O3 layer may fill the pores between the TiCh nanoparticles in the nanoporous structures.
- Curves 1814, 1824, 1834, 1844, and 1852 in FIG. 18C show the atomic concentrations of carbon, oxygen, silicon, titanium, and aluminum, respectively, in the substrate, the overcoat layer, and the AI2O3 layer.
- the atomic concentration of carbon is 0% in the AI2O3 layer, and about 0% in the overcoat layer.
- the atomic concentration of oxygen is about 65% in the AhCrilayer. and greater than about 66% in the overcoat layer.
- Curve 1834 shows that the atomic concentration of silicon is about 0% in the back-fill layer and the overcoat layer.
- the atomic concentration of titanium is about 0% in the AI2O3 layer, and about 25% in the overcoat layer.
- the atomic concentration of aluminum is about 35% in the AI2O3 layer, and about 10% in the overcoat layer.
- FIG. 18C shows that the atomic concentrations of aluminum and titanium in the back-filled overcoat layer may be uniform in the thickness (depth) direction.
- the back filled overcoat layer may have a refractive index about 2.07 and a density about 3.32 g/cm 3 .
- FIG. 18D illustrates correlations between the refractive indices and the densities of various layers in the examples of structures of FIGS. 18A-18C.
- FIG. 18D shows the refractive index (1.87) and the density (2.67 g/cm 3 ) of the overcoat layer of FIG. 18 A.
- a data point 1862 in FIG. 18D shows the refractive index (2.02) and the density (2.99 g/cm 3 ) of the overcoat layer of FIG. 18B that is back-filled with a siloxane-based material, which has a refractive index about 1.5 and a density about 2.99 g/cm 3 as represented by a data point 1864.
- a data point 1866 in FIG. 18D shows the refractive index (2.07) and the density (3.32g/cm 3 ) of the overcoat layer of FIG. 18C that is back-filled with an AI2O3 layer, which has a refractive index about 1.6 and a density about 2.66 g/cm 3 as represented by a data point 1868.
- FIGS. 19A-19E illustrate an example of a process of fabricating a surface-relief grating including an overcoat layer having a high refractive index and a low loss according to certain embodiments.
- FIG. 19A shows that an overcoat material may be dispensed on a surface-relief grating 1910 on a substrate 1905 to form an overcoat layer 1920 for surface- relief grating 1910.
- the overcoat material may include a resin (e.g., acrylate resin with photo radical generator or thermal radical generator), nanoparticles (e.g., T1O2 nanoparticles and/or NbOx nanoparticles), and a solvent (e.g., PGMEA or DPGME/TPM).
- a resin e.g., acrylate resin with photo radical generator or thermal radical generator
- nanoparticles e.g., T1O2 nanoparticles and/or NbOx nanoparticles
- a solvent e.g., PGMEA
- the overcoat material may include a sol-gel material that includes a solution and a high-refractive index oxide precursor (e.g., Ti precursor) and has been partially or fully condensed into an extended network.
- the sol-gel material may include EMD MHM-63, Philips high refractive index sol-gel formulation, or organic solvent-soluble Titania with ligands in a solvent (e.g., PGMEA or DPGME/TPM).
- the overcoat material may have a refractive index about 1.95.
- the overcoat material may be dispensed by, for example, spin coating or inkjet printing.
- the amount of the overcoat material dispensed on surface-relief grating 1910 may be determined based on the dimensions of the grating grooves and the desired thickness of the overburden (e.g., the portion of the overcoat layer on top of the grating ridges).
- the top surface of overcoat layer 1920 may not be flat as shown in the illustrated example.
- the height of the top surface at the grating ridge regions may be greater than the height of the top surface at the grating groove regions.
- overcoat layer 1920 may be baked to remove the solvent from the overcoat layer. Baking may help to remove the solvent and the trapped air such that the overcoat material in the overcoat layer may be more uniform or homogeneous.
- FIG. 19B shows that a planar imprint stamp 1930 (e.g., a soft stamp or mold described above) may be laminated or otherwise applied on overcoat layer 1920 in an imprint process.
- planar imprint stamp 1930 may include PDMS or another silicone elastomer or silicon-based organic polymer.
- planar imprint stamp 1930 may include ETFE, PFPE, or other fluorinated polymer or acrylic polymer materials.
- the bottom surface of planar imprint stamp 1930 that contacts overcoat layer 1920 may have a low surface roughness.
- Planar imprint stamp 1930 may be pressed against overcoat layer 1920, for example, using a roller as described above with respect to, for example, FIG. 1 IB.
- FIG. 19C shows that overcoat layer 1920 may then be cured (e.g., using UV light) to crosslink and fix the base resin in the overcoat material as described above.
- planar imprint stamp 1930 may be delaminated or otherwise detached from overcoat layer 1920 and surface-relief grating 1910, as described above with respect to, for example, FIG. 11C.
- the top surface of overcoat layer 1920 can be flat and smooth.
- the overburden can be thin, such as less than about 20 nm.
- FIG. 19D shows that a high-energy treatment process (e.g., RTA, LSA, or UV irradiation) may be performed on overcoat layer 1920 to remove the organic materials (e.g., organic ligands that decorate the TiCh nanoparticles and/or NbOx nanoparticles,) in overcoat layer 1920.
- a high-energy treatment process e.g., RTA, LSA, or UV irradiation
- overcoat layer 1920 may become a porous layer 1922 that may have a lower refractive index due to the removal of the organic materials.
- overcoat layer 1920 may have a refractive index about 1.95, while porous layer 1922 may have a refractive index about 1.88 or lower.
- ARC layer 1940 may be deposited on porous layer 1922.
- ARC layer 1940 may include organic and/or inorganic materials and may back-fill porous layer 1922 to form a back-filled overcoat layer 1924 that may have a higher refractive index (due to the back fill of the porous structures) and a low absorption loss (due to the removal of the degraded organics and other organics that can be degraded).
- porous layer 1922 may have a refractive index about 1.88
- back-filled overcoat layer 1924 may have a refractive index about 2.03 or higher.
- the organic and/or inorganic materials that back-fill porous layer 1922 may have a low optical loss, and may include, for example, organic materials such as acrylate, polystyrenics, epoxy based organic materials, siloxane based materials, inorganic materials such as AI2O3, S1O2, ZrC , Nb205, T1O2, Ta20s, and the like, or a combination of organic materials and inorganic materials describe above.
- Depositing ARC layer 1940 may include an inkjet coating process, a spin coating process, an ALD process, a PVD process, an CVD process, or a combination thereof.
- the ALD process may use ALD precursors, such as TiCL and H2O, TDMAT and O3, TDMAZ/TMA and H2O, or the like.
- FIGS. 20A-20E illustrate an example of a process of fabricating a surface-relief grating including grating ridges having a high refractive index and a low loss according to certain embodiments.
- FIG. 20A shows that a resin material 2010 may be dispensed on a substrate 2005.
- resin material 2010 may include a resin (e.g., acrylate resin with photo radical generator or thermal radical generator), nanoparticles (e.g., T1O2 nanoparticles and/or NbOx nanoparticles), and a solvent (e.g., PGMEA or DPGME/TPM).
- resin material 2010 may have a refractive index about 1.95.
- Resin material 2010 may be dispensed by, for example, spin coating or inkjet coating.
- the amount of resin material 2010 dispensed on substrate 2005 may be determined based on, for example, the depth of the grating grooves and the duty cycle of the grating.
- resin material 2010 may be baked to remove the solvent and the trapped air such that the resin material may be more uniform or homogeneous.
- FIG. 20B shows that an imprint stamp 2020 (e.g., a soft stamp) may be laminated or otherwise applied on resin material 2010 in an imprint process.
- imprint stamp 2020 may include PDMS or another silicone elastomer or silicon-based organic polymer.
- imprint stamp 2020 may include ETFE, PFPE, or other fluorinated polymer or acrylic polymer materials.
- the surfaces of imprint stamp 2020 that contacts resin material 2010 may have surface-relief structures.
- Imprint stamp 2020 may be pressed against resin material 2010, for example, using a roller as described above with respect to, for example, FIG. 1 IB.
- the surface-relief structures in imprint stamp 2020 may be transferred to resin material 2010 such that surface-relief structures complementary to the surface-relief structures in imprint stamp 2020 may be formed in resin material 2010.
- FIG. 20C shows that resin material 2010 may be cured (e.g., using UV light) to crosslink and fix the base resin in the resin material as described above.
- imprint stamp 2020 may be delaminated or otherwise detached from resin material 2010, thereby forming surface-relief grating 2012 as described above with respect to, for example, FIG. 11C.
- surface-relief grating 2012 shown in FIG. 20C includes straight grating ridges, in some embodiments, surface-relief grating 2012 may include slanted grating ridges.
- the grating period, duty cycle, and/or depth of surface-relief grating 2012 may be constant or may be variable across the grating.
- FIG. 20D shows that a high-energy treatment process (e.g., RTA, LSA, or UV irradiation) may be performed on surface-relief grating 2012 to remove the organic materials (e.g., organic ligands that decorate TiC nanoparticles and/or NbOx nanoparticles) in surface- relief grating 2012.
- a high-energy treatment process e.g., RTA, LSA, or UV irradiation
- surface-relief grating 2012 may become porous and thus may have a reduced refractive index due to the removal of the organic materials.
- surface-relief grating 2012 may have a refractive index about 1.95 before the high-energy treatment process, and may have a refractive index about 1.87 after the high-energy treatment process.
- FIG. 20E shows that an overcoat layer 2030 may be deposited on surface-relief grating 2012.
- overcoat layer 2030 may include organic and/or inorganic materials and may back-fill the porous surface-relief grating 2012 to form a back-filled surface-relief grating 2012 that may have a higher refractive index (due to the back fill of the porous structures) and a low absorption loss (due to the removal of the degraded organics and other organics that can be degraded).
- surface-relief grating 2012 may have a refractive index about 1.87 after the high-energy treatment process, and may have a refractive index about 2.07 after overcoat layer 2030 is deposited on surface-relief grating 2012 to fill pores in surface-relief grating 2012.
- the organic and/or inorganic materials that back-fill the pores in surface-relief grating 2012 may have a low optical loss, and may include, for example, organic materials such as acrylate, polystyrenics, epoxy based organic materials, siloxane based materials, inorganic materials such as AI2O3, S1O2, ZrC , Nb20s, T1O2, TarOy and the like, or a combination of organic materials and inorganic materials describe above.
- Depositing overcoat layer 2030 may include, for example, an inkjet-coating process or a spin coating process.
- FIG. 21 includes a flowchart 2100 illustrating an example of a process of fabricating a surface-relief grating that has a high refractive index contrast and a low loss according to certain embodiments. It is noted that the specific operations illustrated in FIG.
- FIG. 21 provide a particular process of fabricating a surface-relief grating. Other sequences of operations may be performed according to alternative embodiments. Moreover, the individual operations illustrated in FIG. 21 may include multiple sub-steps that may be performed in various sequences as appropriate to the individual operation. Furthermore, additional operations may be added or some operations may not be performed depending on the particular applications.
- One of ordinary skill in the art would recognize many variations, modifications, and alternatives.
- Operations in block 2110 may include depositing a resin layer (or a sol-gel layer) that includes an organic material and metal oxide nanoparticles dispersed in the organic material.
- the resin layer may include, for example, an acrylate resin including photo radical generator or thermal radical generator, 75%-90% metal oxide (e.g., TiOx, ZrOx, and/or NbOx) nanoparticles decorated with organic ligands, and a solvent including PGMEA, DPGME/TPM, or a combination.
- the resin layer may have a refractive index about 1.95 or higher.
- the resin layer may be deposited on a substrate or a surface-relief grating using spin coating, inkjet coating, or spray coating.
- the resin layer may be baked to remove the solvent. Baking may help to remove the solvent and the trapped air such that the material in the resin layer may be more uniform or homogeneous.
- a sol-gel layer rather than a resin layer, may be deposited on a surface- relief grating to form an overcoat layer.
- the sol-gel material may include a solution and a high-refractive index oxide precursor (e.g., Ti precursor), and may have been at least partially condensed into an extended network.
- the sol-gel material may include organic solvent soluble Titania with organic ligands, and a solvent including PGMEA,
- the sol-gel material may include EMD MHM-63 or Philips high-refractive index sol-gel formulation.
- Optional operations in block 2115 may include imprinting the resin layer by, for example, laminating a planar imprint stamp or an imprint stamp with structures complementary to the structures of a surface-relief grating on the resin layer.
- the planar imprint stamp may include PDMS or another silicone elastomer or silicon- based organic polymer.
- the planar imprint stamp may include ETFE, PFPE, or other fluorinated polymer or acrylic polymer materials.
- the planar imprint stamp may be used to form an overcoat layer with a flat top surface.
- the imprint stamp with structures complementary to the structures of a surface-relief grating may be used to form the surface-relief grating in the resin layer.
- Operations in block 2120 may include curing the resin layer (e.g., using UV light) to crosslink and fix the base resin in the resin layer.
- the crosslinked base resin may hold the metal oxide nanoparticles in place.
- the imprint stamp (if used) may be delaminated from the resin layer to leave a flat top surface (for an overcoat layer) on the resin layer or a surface-relief grating in the resin layer.
- Operations in block 2130 may include performing a high-energy treatment process (e.g., RTA, LSA, or UV irradiation) on the cured resin layer to remove the organic materials (e.g., organic ligands that decorate TiCh nanoparticles and/or NbOx nanoparticles), including the organic materials that have been degraded during the fabrication processes (e.g., UV curing).
- the resin layer may become a porous layer that may include metal oxide nanoparticles and pores between the metal oxide nanoparticles.
- the porous layer may mainly include Ti and oxygen atoms.
- the porous layer may have a lower refractive index due to the removal of the organic materials.
- Operations in block 2140 may include depositing a back-fill material that has a low optical loss on the porous layer to fill the pores in the porous layer.
- Depositing the back-fill material may include an inkjet coating process, a spin coating process, an ALD process, an SIS process, a PVD process, an iCVD process, or a combination thereof.
- the ALD precursors used in the ALD process may include, for example, TiCU and FLO, TDMAT and O3, TDMAZ/TMA and FLO, or a combination thereof.
- the back-fill material may include of an organic material, an inorganic material, or a combination thereof.
- the organic material may include, for example, acrylate, polystyrenics, epoxy, siloxane, or a combination thereof.
- the inorganic material may include, for example, AI2O3, S1O2, ZrCh, M>2q5, TiCh, Ta20s, or a combination thereof.
- the porous layer with the pores filled with the back-fill material may have a higher refractive index, such as greater than about 2.0. Thus, a low-loss, high- refractive index overcoat layer or surface-relief grating may be formed.
- Embodiments of the invention may include or be implemented in conjunction with an artificial reality system.
- Artificial reality is a form of reality that has been adjusted in some manner before presentation to a user, which may include, for example, a virtual reality (VR), an augmented reality (AR), a mixed reality (MR), a hybrid reality, or some combination and/or derivatives thereof.
- Artificial reality content may include completely generated content or generated content combined with captured (e.g., real-world) content.
- the artificial reality content may include video, audio, haptic feedback, or some combination thereof, and any of which may be presented in a single channel or in multiple channels (such as stereo video that produces a three-dimensional effect to the viewer). Additionally, in some embodiments, artificial reality may also be associated with applications, products, accessories, services, or some combination thereof, that are used to, for example, create content in an artificial reality and/or are otherwise used in (e.g., perform activities in) an artificial reality.
- the artificial reality system that provides the artificial reality content may be implemented on various platforms, including a head-mounted display (HMD) connected to a host computer system, a standalone HMD, a mobile device or computing system, or any other hardware platform capable of providing artificial reality content to one or more viewers.
- HMD head-mounted display
- FIG. 22 is a simplified block diagram of an example electronic system 2200 of an example near-eye display (e.g., HMD device) for implementing some of the examples disclosed herein.
- Electronic system 2200 may be used as the electronic system of an HMD device or other near-eye displays described above.
- electronic system 2200 may include one or more processor(s) 2210 and a memory 2220.
- Processor(s) 2210 may be configured to execute instructions for performing operations at a number of components, and can be, for example, a general-purpose processor or microprocessor suitable for implementation within a portable electronic device.
- Processor(s) 2210 may be communicatively coupled with a plurality of components within electronic system 2200.
- Bus 2240 may be any subsystem adapted to transfer data within electronic system 2200.
- Bus 2240 may include a plurality of computer buses and additional circuitry to transfer data.
- Memory 2220 may be coupled to processor(s) 2210. In some embodiments, memory 2220 may offer both short-term and long-term storage and may be divided into several units. Memory 2220 may be volatile, such as static random access memory (SRAM) and/or dynamic random access memory (DRAM) and/or non-volatile, such as read-only memory (ROM), flash memory, and the like. Furthermore, memory 2220 may include removable storage devices, such as secure digital (SD) cards. Memory 2220 may provide storage of computer-readable instructions, data structures, program modules, and other data for electronic system 2200. In some embodiments, memory 2220 may be distributed into different hardware modules. A set of instructions and/or code might be stored on memory 2220.
- SRAM static random access memory
- DRAM dynamic random access memory
- ROM read-only memory
- flash memory flash memory
- SD secure digital
- the instructions might take the form of executable code that may be executable by electronic system 2200, and/or might take the form of source and/or installable code, which, upon compilation and/or installation on electronic system 2200 (e.g., using any of a variety of generally available compilers, installation programs, compression/decompression utilities, etc.), may take the form of executable code.
- memory 2220 may store a plurality of application modules 2222 through 2224, which may include any number of applications. Examples of applications may include gaming applications, conferencing applications, video playback applications, or other suitable applications. The applications may include a depth sensing function or eye tracking function. Application modules 2222-2224 may include particular instructions to be executed by processor(s) 2210. In some embodiments, certain applications or parts of application modules 2222-2224 may be executable by other hardware modules 2280. In certain embodiments, memory 2220 may additionally include secure memory, which may include additional security controls to prevent copying or other unauthorized access to secure information.
- memory 2220 may include an operating system 2225 loaded therein.
- Operating system 2225 may be operable to initiate the execution of the instructions provided by application modules 2222-2224 and/or manage other hardware modules 2280 as well as interfaces with a wireless communication subsystem 2230 which may include one or more wireless transceivers.
- Operating system 2225 may be adapted to perform other operations across the components of electronic system 2200 including threading, resource management, data storage control and other similar functionality.
- Wireless communication subsystem 2230 may include, for example, an infrared communication device, a wireless communication device and/or chipset (such as a Bluetooth® device, an IEEE 802.11 device, a Wi-Fi device, a WiMax device, cellular communication facilities, etc.), and/or similar communication interfaces.
- Electronic system 2200 may include one or more antennas 2234 for wireless communication as part of wireless communication subsystem 2230 or as a separate component coupled to any portion of the system.
- wireless communication subsystem 2230 may include separate transceivers to communicate with base transceiver stations and other wireless devices and access points, which may include communicating with different data networks and/or network types, such as wireless wide-area networks (WWANs), wireless local area networks (WLANs), or wireless personal area networks (WPANs).
- WWAN may be, for example, a WiMax (IEEE 802.16) network.
- WLAN may be, for example, an IEEE 802.1 lx network.
- a WPAN may be, for example, a Bluetooth network, an IEEE 802.15x, or some other types of network.
- the techniques described herein may also be used for any combination of WWAN, WLAN, and/or WPAN.
- Wireless communications subsystem 2230 may permit data to be exchanged with a network, other computer systems, and/or any other devices described herein.
- Wireless communication subsystem 2230 may include a means for transmitting or receiving data, such as identifiers of HMD devices, position data, a geographic map, a heat map, photos, or videos, using antenna(s) 2234 and wireless link(s) 2232.
- Embodiments of electronic system 2200 may also include one or more sensors 2290.
- Sensor(s) 2290 may include, for example, an image sensor, an accelerometer, a pressure sensor, a temperature sensor, a proximity sensor, a magnetometer, a gyroscope, an inertial sensor (e.g., a module that combines an accelerometer and a gyroscope), an ambient light sensor, or any other similar module operable to provide sensory output and/or receive sensory input, such as a depth sensor or a position sensor.
- sensor(s) 2290 may include one or more inertial measurement units (IMUs) and/or one or more position sensors.
- IMUs inertial measurement units
- An IMU may generate calibration data indicating an estimated position of the HMD device relative to an initial position of the HMD device, based on measurement signals received from one or more of the position sensors.
- a position sensor may generate one or more measurement signals in response to motion of the HMD device. Examples of the position sensors may include, but are not limited to, one or more accelerometers, one or more gyroscopes, one or more magnetometers, another suitable type of sensor that detects motion, a type of sensor used for error correction of the IMU, or some combination thereof.
- the position sensors may be located external to the IMU, internal to the IMU, or some combination thereof. At least some sensors may use a structured light pattern for sensing.
- Electronic system 2200 may include a display module 2260.
- Display module 2260 may be a near-eye display, and may graphically present information, such as images, videos, and various instructions, from electronic system 2200 to a user. Such information may be derived from one or more application modules 2222-2224, virtual reality engine 2226, one or more other hardware modules 2280, a combination thereof, or any other suitable means for resolving graphical content for the user (e.g., by operating system 2225).
- Display module 2260 may use liquid crystal display (LCD) technology, light-emitting diode (LED) technology (including, for example, OLED, ILED, pLED, AMOLED, TOLED, etc.), light emitting polymer display (LPD) technology, or some other display technology.
- LCD liquid crystal display
- LED light-emitting diode
- LPD light emitting polymer display
- Electronic system 2200 may include a user input/output module 2270.
- User input/output module 2270 may allow a user to send action requests to electronic system 2200.
- An action request may be a request to perform a particular action.
- an action request may be to start or end an application or to perform a particular action within the application.
- User input/output module 2270 may include one or more input devices.
- Example input devices may include a touchscreen, a touch pad, microphone(s), button(s), dial(s), switch(es), a keyboard, a mouse, a game controller, or any other suitable device for receiving action requests and communicating the received action requests to electronic system 2200.
- user input/output module 2270 may provide haptic feedback to the user in accordance with instructions received from electronic system 2200.
- the haptic feedback may be provided when an action request is received or has been performed.
- Electronic system 2200 may include a camera 2250 that may be used to take photos or videos of a user, for example, for tracking the user’s eye position. Camera 2250 may also be used to take photos or videos of the environment, for example, for VR, AR, or MR applications. Camera 2250 may include, for example, a complementary metal-oxide- semiconductor (CMOS) image sensor with a few millions or tens of millions of pixels. In some implementations, camera 2250 may include two or more cameras that may be used to capture 3-D images.
- CMOS complementary metal-oxide- semiconductor
- electronic system 2200 may include a plurality of other hardware modules 2280.
- Each of other hardware modules 2280 may be a physical module within electronic system 2200. While each of other hardware modules 2280 may be permanently configured as a structure, some of other hardware modules 2280 may be temporarily configured to perform specific functions or temporarily activated. Examples of other hardware modules 2280 may include, for example, an audio output and/or input module (e.g., a microphone or speaker), a near field communication (NFC) module, a rechargeable battery, a battery management system, a wired/wireless battery charging system, etc. In some embodiments, one or more functions of other hardware modules 2280 may be implemented in software.
- memory 2220 of electronic system 2200 may also store a virtual reality engine 2226.
- Virtual reality engine 2226 may execute applications within electronic system 2200 and receive position information, acceleration information, velocity information, predicted future positions, or some combination thereof of the HMD device from the various sensors.
- the information received by virtual reality engine 2226 may be used for producing a signal (e.g., display instructions) to display module 2260.
- a signal e.g., display instructions
- virtual reality engine 2226 may generate content for the HMD device that mirrors the user’s movement in a virtual environment.
- virtual reality engine 2226 may perform an action within an application in response to an action request received from user input/output module 2270 and provide feedback to the user.
- the provided feedback may be visual, audible, or haptic feedback.
- processor(s) 2210 may include one or more GPUs that may execute virtual reality engine 2226.
- the above-described hardware and modules may be implemented on a single device or on multiple devices that can communicate with one another using wired or wireless connections.
- some components or modules such as GPUs, virtual reality engine 2226, and applications (e.g., tracking application), may be implemented on a console separate from the head-mounted display device.
- one console may be connected to or support more than one HMD.
- electronic system 2200 may be included in electronic system 2200.
- functionality of one or more of the components can be distributed among the components in a manner different from the manner described above.
- electronic system 2200 may be modified to include other system environments, such as an AR system environment and/or an MR environment.
- embodiments were described as processes depicted as flow diagrams or block diagrams. Although each may describe the operations as a sequential process, many of the operations may be performed in parallel or concurrently. In addition, the order of the operations may be rearranged. A process may have additional steps not included in the figure.
- embodiments of the methods may be implemented by hardware, software, firmware, middleware, microcode, hardware description languages, or any combination thereof.
- the program code or code segments to perform the associated tasks may be stored in a computer-readable medium such as a storage medium. Processors may perform the associated tasks.
- components that can include memory can include non-transitory machine-readable media.
- machine-readable medium and “computer-readable medium,” as used herein, refer to any storage medium that participates in providing data that causes a machine to operate in a specific fashion.
- various machine-readable media might be involved in providing instructions/code to processing units and/or other device(s) for execution. Additionally or alternatively, the machine-readable media might be used to store and/or carry such instructions/code.
- a computer-readable medium is a physical and/or tangible storage medium. Such a medium may take many forms, including, but not limited to, non-volatile media, volatile media, and transmission media.
- Computer-readable media include, for example, magnetic and/or optical media such as compact disk (CD) or digital versatile disk (DVD), punch cards, paper tape, any other physical medium with patterns of holes, a RAM, a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), a FLASH-EPROM, any other memory chip or cartridge, a carrier wave as described hereinafter, or any other medium from which a computer can read instructions and/or code.
- CD compact disk
- DVD digital versatile disk
- PROM programmable read-only memory
- EPROM erasable programmable read-only memory
- FLASH-EPROM any other memory chip or cartridge
- carrier wave as described hereinafter
- a computer program product may include code and/or machine-executable instructions that may represent a procedure, a function, a subprogram, a program, a routine, an application (App), a subroutine, a module, a software package, a class, or any combination of instructions, data structures, or program statements.
- code and/or machine-executable instructions may represent a procedure, a function, a subprogram, a program, a routine, an application (App), a subroutine, a module, a software package, a class, or any combination of instructions, data structures, or program statements.
- the term “at least one of’ if used to associate a list, such as A, B, or C, can be interpreted to mean A, B, C, or a combination of A, B, and/or C, such as AB, AC, BC, AA, ABC, AAB, ACC, AABBCCC, or the like.
- Such configuration can be accomplished, for example, by designing electronic circuits to perform the operation, by programming programmable electronic circuits (such as microprocessors) to perform the operation such as by executing computer instructions or code, or processors or cores programmed to execute code or instructions stored on a non-transitory memory medium, or any combination thereof.
- Processes can communicate using a variety of techniques, including, but not limited to, conventional techniques for inter-process communications, and different pairs of processes may use different techniques, or the same pair of processes may use different techniques at different times.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Diffracting Gratings Or Hologram Optical Elements (AREA)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US202163175357P | 2021-04-15 | 2021-04-15 | |
US17/720,058 US20220334289A1 (en) | 2021-04-15 | 2022-04-13 | Low-loss optical materials and processes |
PCT/US2022/025021 WO2022221662A1 (en) | 2021-04-15 | 2022-04-15 | Low-loss optical materials and processes |
Publications (1)
Publication Number | Publication Date |
---|---|
EP4323815A1 true EP4323815A1 (de) | 2024-02-21 |
Family
ID=81579961
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP22721224.8A Pending EP4323815A1 (de) | 2021-04-15 | 2022-04-15 | Optische materialien und verfahren mit geringem verlust |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP4323815A1 (de) |
WO (1) | WO2022221662A1 (de) |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20150322286A1 (en) * | 2012-11-27 | 2015-11-12 | The Regents Of The University Of California | Polymerized Metal-Organic Material for Printable Photonic Devices |
US20200249568A1 (en) * | 2019-02-05 | 2020-08-06 | Facebook Technologies, Llc | Curable formulation with high refractive index and its application in surface relief grating using nanoimprinting lithography |
US11391950B2 (en) * | 2019-06-26 | 2022-07-19 | Meta Platforms Technologies, Llc | Techniques for controlling effective refractive index of gratings |
-
2022
- 2022-04-15 EP EP22721224.8A patent/EP4323815A1/de active Pending
- 2022-04-15 WO PCT/US2022/025021 patent/WO2022221662A1/en active Application Filing
Also Published As
Publication number | Publication date |
---|---|
WO2022221662A1 (en) | 2022-10-20 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US11662584B2 (en) | Gradient refractive index grating for display leakage reduction | |
US11550083B2 (en) | Techniques for manufacturing slanted structures | |
US10845596B2 (en) | Slanted surface relief grating for rainbow reduction in waveguide display | |
US11667059B2 (en) | Techniques for reducing surface adhesion during demolding in nanoimprint lithography | |
US20220082739A1 (en) | Techniques for manufacturing variable etch depth gratings using gray-tone lithography | |
US11249230B2 (en) | Duty cycle, depth, and surface energy control in nano fabrication | |
US20220206232A1 (en) | Layered waveguide fabrication by additive manufacturing | |
EP3903141A1 (de) | Überbeschichtung von schrägen oberflächenreliefstrukturen mittels atomlagenabscheidung | |
US20220334302A1 (en) | In situ core-shell nanoparticle preparation | |
US11709422B2 (en) | Gray-tone lithography for precise control of grating etch depth | |
EP3528032A2 (de) | Abgeschrägtes oberflächenreliefgitter für regenbogenminderung bei einer wellenleiteranzeige | |
US10809448B1 (en) | Reducing demolding stress at edges of gratings in nanoimprint lithography | |
US20220334289A1 (en) | Low-loss optical materials and processes | |
US20230041380A1 (en) | Nanoparticle treatment for optical coating | |
EP4323815A1 (de) | Optische materialien und verfahren mit geringem verlust | |
WO2022221634A1 (en) | In situ core-shell nanoparticle-cluster preparation | |
US20240151971A1 (en) | Techniques for controlling overburden planarization | |
WO2023018680A1 (en) | Nanoparticle treatment for optical coating | |
CN117120885A (zh) | 低损耗光学材料和工艺 | |
CN117203557A (zh) | 核-壳式纳米颗粒簇的原位制备 | |
WO2022146904A1 (en) | Layered waveguide fabrication by additive manufacturing |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: UNKNOWN |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE |
|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE |
|
17P | Request for examination filed |
Effective date: 20231013 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
DAV | Request for validation of the european patent (deleted) | ||
DAX | Request for extension of the european patent (deleted) |