Multilayer optical barrier
A liquid lens architecture includes a transparent substrate, a multilayer thermoplastic polyurethane (TPU)-based membrane overlying at least a portion of the transparent substrate, and a liquid layer disposed between and abutting the transparent substrate and the multilayer thermoplastic polyurethane-based membrane. The TPU-based membrane may exhibit a reversible elastic response to imposed strains of up to approximately 2% and is configured to limit the transpiration of fluid to less than approximately 10 −2 g/m 2 /day.
1. A liquid lens comprising:
a transparent substrate;
a multilayer membrane overlying the transparent substrate, the multilayer membrane comprising two or more thermoplastic polyurethane layers; and
a liquid layer disposed between the transparent substrate and the multilayer membrane.
2. The liquid lens of claim 1 , wherein the multilayer membrane comprises a transparent aliphatic thermoplastic polyurethane layer and a transparent aromatic thermoplastic polyurethane layer.
3. The liquid lens of claim 1 , wherein a total thickness of the multilayer membrane is less than approximately 1 mm.
4. The liquid lens of claim 1 , wherein the multilayer membrane comprises alternating layers of a transparent aliphatic thermoplastic polyurethane material and a transparent aromatic thermoplastic polyurethane material.
5. The liquid lens of claim 4 , wherein each of the alternating layers has a thickness of less than approximately 10 micrometers.
6. The liquid lens of claim 1 , wherein the multilayer membrane comprises a transparent barrier layer.
7. The liquid lens of claim 6 , wherein the transparent barrier layer comprises a polymer selected from the group consisting of polyvinylidene fluoride, chlorotrifluoroethylene, polyvinylidene chloride, and ethylene vinyl alcohol copolymer.
8. The liquid lens of claim 1 , further comprising an antireflective coating disposed directly over the multilayer membrane.
9. The liquid lens of claim 1 , wherein the multilayer membrane is configured to have a reversible elastic response to strains up to approximately 2% and to limit transpiration of fluid therethrough to less than approximately 10 −2 g/m 2 /day.
10. A liquid lens comprising:
a transparent substrate;
a multilayer membrane overlying the transparent substrate, the multilayer membrane comprising alternating layers of a thermoplastic polyurethane and an optically transparent polymer; and
a liquid layer disposed between the transparent substrate and the multilayer membrane.
11. The liquid lens of claim 10 , wherein the thermoplastic polyurethane layers comprise a transparent aliphatic thermoplastic polyurethane material or a transparent aromatic thermoplastic polyurethane material.
12. The liquid lens of claim 10 , wherein the optically transparent polymer layers comprise a polymer selected from the group consisting of polyvinylidene fluoride, chlorotrifluoroethylene, polyvinylidene chloride, and ethylene vinyl alcohol copolymer.
13. The liquid lens of claim 10 , wherein a thickness of each thermoplastic polyurethane layer is greater than a thickness of each optically transparent polymer layer.
14. A method comprising:
forming alternating layers of a transparent thermoplastic polyurethane layer and a transparent polymer layer over a transparent substrate;
to form a multilayer membrane; and
forming a liquid layer between the transparent substrate and the multilayer membrane to form a liquid lens.
15. The method of claim 14 , wherein the transparent thermoplastic polyurethane layer comprises an aliphatic thermoplastic polyurethane material or an aromatic thermoplastic polyurethane material.
16. The method of claim 14 , wherein the transparent polymer layer comprises a polymer selected from the group consisting of polyvinylidene fluoride, chlorotrifluoroethylene, polyvinylidene chloride, and ethylene vinyl alcohol copolymer.
17. The method of claim 14 , wherein a thickness of the transparent thermoplastic polyurethane layer is greater than a thickness of the transparent polymer layer.
18. The method of claim 14 , further comprising forming an antireflective coating over the multilayer membrane.
19. The method of claim 14 , further comprising applying an in-plane tensile stress to the multilayer membrane.
20. The method of claim 14 , further comprising forming a liquid layer over the multilayer membrane.