Flexible multi-layered cover lens stacks for foldable displays
Embodiments described and discussed herein generally relate to flexible or foldable display devices, and more specifically to flexible cover lens assemblies. In one or more embodiments, a flexible cover lens assembly contains a substrate, an anti-fingerprint coating layer, and an adhesion promotion layer disposed between the substrate and the anti-fingerprint coating layer.
1. A flexible cover lens assembly, comprising:
a substrate;
a wet hardcoat layer disposed directly on the substrate, wherein the wet hardcoat layer comprises an acrylate, and wherein the acrylate comprises a radiation curable acrylate, aliphatic urethane acrylate, a copolymer thereof, an elastomer thereof, or any combination thereof;
an adhesion promotion layer disposed directly on the wet hardcoat layer, wherein the adhesion promotion layer comprises a material selected from the group consisting of silicon oxide, silicon carbide, silicon oxycarbide, silicon nitride, silicon oxynitride, silicon oxycarbide nitride, a dopant thereof, and any combination thereof, and wherein the adhesion promotion layer has a refractive index in a range from about 1.40 to about 1.55;
a dry hardcoat layer disposed directly on the adhesion promotion layer, wherein the dry hardcoat layer comprises a material selected from the group consisting of silicon carbide, silicon oxycarbide, silicon oxycarbide nitride, a dopant thereof, and any combination thereof; and
an anti-fingerprint coating layer disposed directly on the dry hardcoat layer;
wherein the flexible cover lens assembly has a critical strain of greater than 1% to about 15%.
2. The flexible cover lens assembly of claim 1 , wherein the flexible cover lens assembly has a critical strain in a range from about 1.5% to about 10%.
3. The flexible cover lens assembly of claim 1 , wherein the adhesion promotion layer comprises silicon oxide, silicon nitride, silicon oxynitride, or any combination thereof.
4. The flexible cover lens assembly of claim 1 , wherein the adhesion promotion layer has a gradient of carbon concentration across a thickness of the adhesion promotion layer.
5. The flexible cover lens assembly of claim 1 , wherein the adhesion promotion layer comprises from about 2 sublayers to about 10 sublayers.
6. The flexible cover lens assembly of claim 1 , wherein the adhesion promotion layer comprises a plurality of sublayers contained therein, and wherein the plurality of sublayers comprises a gradient of carbon concentration across a thickness of the adhesion promotion layer.
7. The flexible cover lens assembly of claim 1 , wherein the adhesion promotion layer comprises a plurality of sublayers contained therein, and wherein the plurality of sublayers comprises a gradient of hardness across a thickness of the adhesion promotion layer.
8. The flexible cover lens assembly of claim 1 , wherein the adhesion promotion layer comprises a plurality of sublayers contained therein, and wherein the plurality of sublayers has a nano-indentation hardness across a thickness of the adhesion promotion layer within a range from about 0.1 GPa to about 5 GPa, as measured by nano-indentation technique.
9. The flexible cover lens assembly of claim 1 , wherein the dry hardcoat layer has a nano-indentation hardness in a range from about 2 GPa to about 4 GPa.
10. The flexible cover lens assembly of claim 1 , wherein the dry hardcoat layer has a refractive index of about 1.42 to about 1.55 and a nano-indentation hardness in a range from about 1 GPa to about 5 GPa.
11. A flexible cover lens assembly, comprising:
a substrate;
a wet hardcoat layer disposed directly on the substrate, wherein the wet hardcoat layer comprises an acrylate, and wherein the acrylate comprises a radiation curable acrylate, aliphatic urethane acrylate, a copolymer thereof, an elastomer thereof, or any combination thereof;
an adhesion promotion layer disposed directly on the wet hardcoat layer, wherein the adhesion promotion layer comprises a material selected from the group consisting of silicon oxide, silicon carbide, silicon oxycarbide, silicon nitride, silicon oxynitride, silicon oxycarbide nitride, a dopant thereof, and any combination thereof;
a dry hardcoat layer disposed directly on the adhesion promotion layer, wherein the dry hardcoat layer comprises a material selected from the group consisting of silicon carbide, silicon oxycarbide, silicon oxycarbide nitride, a dopant thereof, and any combination thereof, and wherein the dry hardcoat layer has:
a refractive index of about 1.42 to about 1.55;
a nano-indentation hardness in a range from about 1 GPa to about 5 GPa; and
a porosity of about 1% to about 8%; and
an anti-fingerprint coating layer disposed directly on the dry hardcoat layer;
wherein the flexible cover lens assembly has a critical strain of greater than 1% to about 15%.
12. The flexible cover lens assembly of claim 11 , wherein the flexible cover lens assembly has a critical strain in a range from about 1.5% to about 10%.
13. The flexible cover lens assembly of claim 11 , wherein the dry hardcoat layer has a nano-indentation hardness in a range from about 2 GPa to about 4 GPa.
14. A flexible cover lens assembly, comprising:
a substrate;
a wet hardcoat layer disposed directly on the substrate, wherein the wet hardcoat layer comprises an acrylate, and wherein the acrylate comprises a radiation curable acrylate, aliphatic urethane acrylate, a copolymer thereof, an elastomer thereof, or any combination thereof;
an adhesion promotion layer disposed directly on the wet hardcoat layer, wherein the adhesion promotion layer comprises a material selected from the group consisting of silicon oxide, silicon carbide, silicon oxycarbide, silicon nitride, silicon oxynitride, silicon oxycarbide nitride, a dopant thereof, and any combination thereof, and wherein the adhesion promotion layer has a refractive index in a range from about 1.40 to about 1.55;
a dry hardcoat layer disposed directly on the adhesion promotion layer, wherein the dry hardcoat layer comprises a material selected from the group consisting of silicon carbide, silicon oxycarbide, silicon oxycarbide nitride, a dopant thereof, and any combination thereof, and wherein the dry hardcoat layer has a refractive index of about 1.42 to about 1.55; and
an anti-fingerprint coating layer disposed directly on the dry hardcoat layer.
15. The flexible cover lens assembly of claim 14 , wherein the flexible cover lens assembly has a critical strain in a range from about 1.5% to about 10%.
16. The flexible cover lens assembly of claim 14 , wherein the wet hardcoat layer has a porosity of about 6% to about 10%.
17. The flexible cover lens assembly of claim 14 , wherein the refractive index is in a range from about 1.43 to about 1.50.
18. The flexible cover lens assembly of claim 14 , wherein the wet hardcoat layer has a nano-indentation hardness in a range from about 0.5 GPa to about 1.2 GPa, and wherein the wet hardcoat layer has a thickness in a range from about 0.5 μm to about 40 μm.
19. The flexible cover lens assembly of claim 14 , wherein the dry hardcoat layer has a nano-indentation hardness in a range from about 1 GPa to about 5 GPa and a porosity of about 1% to about 8%.
20. The flexible cover lens assembly of claim 19 , wherein the dry hardcoat layer has a nano-indentation hardness in a range from about 2 GPa to about 4 GPa and a porosity of about 3% to about 7%.