Photolithographic patterning of polymeric materials
The invention comprises methods for the photolithographic patterning of features in a photo-curable polymer composition coated onto a plastic substrate. In one embodiment of this invention, the plastic substrate is coated with a reflective film such as a metallic barrier. In another embodiment, the plastic substrate is coated or co-extruded with a polymer barrier layer containing an additive that absorbs the photo-curing radiation. In yet another embodiment the plastic substrate contains an intrinsic additive that absorbs the photo-curing radiation. Combinations of these embodiments are also within the scope of this invention. The methods of the present invention may be advantageously applied to the fabrication of optical waveguides comprising a photo-curable polymer supported on a plastic substrate, but are applicable to the fabrication of any device or object comprising a photo-curable polymer supported on a plastic substrate.
1. An optical device comprising:
a plastic substrate;
an intermediate layer opaque to UV curing radiation deposited over the plastic substrate; and
a patterned UV-cured polymer deposited over the intermediate layer, wherein the intermediate layer shields the plastic substrate from the UV curing radiation, and the optical device is free from polymerized material in gaps between cured polymer regions or at the boundary of said cured polymer regions,
wherein said cured polymer regions define one or more waveguides or lenses which are separated by said gaps.
2. An optical device according to claim 1 wherein said intermediate layer comprises a metal film.
3. An optical device according to claim 1 wherein said intermediate layer comprises a polymer with an additive that absorbs said UV curing radiation.
4. An optical device according to claim 3 wherein said intermediate layer is co-extruded with said plastic substrate.
5. An optical device according to claim 1 wherein said plastic substrate is chosen from the group consisting of polyethylene terephthalate and a polycarbonate.
6. An optical device according to claim 1 wherein the UV-cured polymer comprises a siloxane polymer.
7. A waveguide-based optical touch screen sensor comprising the optical device according to claim 1 .
8. An optical device comprising:
a plastic substrate; a barrier layer deposited over the plastic substrate; and
a patterned radiation-cured polymer deposited over the barrier layer;
wherein the plastic substrate contains an additive that absorbs radiation used to cure the polymer,
wherein the barrier layer is opaque to the radiation and the optical device is free from polymerized material in gaps between cured polymer regions or at the boundary of said cured polymer regions, and
wherein said cured polymer regions define one or more waveguides or lenses which are separated by said gaps.
9. An optical device according to claim 8 , wherein the radiation is UV radiation.
10. An optical device according to claim 8 wherein said plastic substrate is chosen from the group consisting of: polyethylene terephthalate and a polycarbonate.
11. An optical device according to claim 8 wherein the radiation-cured polymer comprises a siloxane polymer.
12. A waveguide-based optical touch screen sensor comprising the optical device according to claim 8 .
13. An optical device comprising:
a plastic substrate;
an intermediate layer opaque to UV curing radiation co-extruded with said plastic substrate; and
a patterned UV-cured polymer deposited thereon, wherein the intermediate layer shields the plastic substrate from the UV curing radiation and the optical device is free from polymerized material in gaps between cured polymer regions or at the boundary of said cured polymer regions,
wherein said cured polymer regions define one or more waveguides or lenses which are separated by said gaps.
14. An optical device according to claim 13 wherein said plastic substrate is chosen from the group consisting of polyethylene terephthalate and a polycarbonate.
15. An optical device according to claim 13 wherein the UV-cured polymer comprises a siloxane polymer.
16. A waveguide-based optical touch screen sensor comprising the optical device according to claim 13 .
17. An optical device comprising:
a plastic substrate having a UV absorbing additive and having a patterned UV-cured polymer deposited over the plastic substrate,
wherein the UV absorbing additive shields the plastic substrate from UV-curing radiation and the optical device is free from polymerized material in gaps between cured polymer regions or at the boundary of said cured polymer regions, and
wherein said cured polymer regions define one or more waveguides or lenses which are separated by said gaps.
18. An optical device according to claim 17 wherein said plastic substrate is chosen from the group consisting of: polyethylene terephthalate comprising a UV absorbing additive; and a polycarbonate comprising a UV absorbing additive.
19. An optical device according to claim 17 wherein the UV-cured polymer comprises a siloxane polymer.
20. A waveguide-based optical touch screen sensor comprising the optical device according to claim 17 .