Microfabrication of organic optical elements
Method of fabricating an optical element. A photodefinable composition is provided that includes (i) a hydrophobic, photodefinable polymer, said photodefinable polymer having a glass transition temperature in the cured state of at least about 80° C.; and (ii) a multiphoton photoinitiator system comprising at least one multiphoton photosensitizer and preferably at least one phtoinitiator that is capable of being photosensitized by the photosensitizer. One or more portions of the composition are imagewise exposed to the electromagnetic energy under conditions effective to photodefinably form at least a portion of a three-dimensional optical element.
1. A method of fabricating a three dimensional optical element, comprising the steps of:
(a) providing a photocurable composition, comprising
(i) a hydrophobic, photodefinable polymer or oligomer, said photodefinable polymer or oligomer having a glass transition temperature in the cured state of at least about 80° C.;
(ii) a multiphoton photoinitiator system; and
(b) imagewise exposing one or more portions of the composition to said electromagnetic energy under conditions effective to photodefinably form at least a portion of a three-dimensional optical element comprising a photoinitiator and a separate photosensitizer.
2. The method of claim 1 , wherein the hydrophobic, photodefinable polymer or oligomer has a glass transition temperature greater than about 100° C.
3. The method of claim 1 , wherein the hydrophobic, photodefinable polymer comprises a polyimide or polyimide precursor.
4. The method of claim 1 , wherein the multiphoton photoinitiator system further comprises an electron donor compound.
5. The method of claim 1 , wherein the photocurable composition further comprises a nonphotodefinable binder.
6. The method of claim 5 , wherein the nonphotodefinable binder comprises a thermoplastic polymer having a glass transition temperature of at least about 80° C.
7. The method of claim 5 , wherein the hydrophobic, photodefinable polymer comprises a polyimide and wherein the nonphotodefinable binder comprises a polyimide.
8. The method of claim 5 , wherein the nonphotodefinable binder comprises a thermosetting polymer having a glass transition temperature of at least about 80° C. when cured.
9. The method of claim 1 , further comprising the step of removing at least an uncured portion of the uncured photocurable composition to recover the resultant optical element.
10. The method of claim 9 , further comprising blanket irradiating the recovered optical element.
11. The method of claim 1 , wherein the optical element comprises a polyimide and the method further comprises subjecting at least the resultant optical element to an imidization treatment.
12. The method of claim 1 , wherein the photocurable composition further comprises a monomer, said monomer forming a homopolymer that has a glass transition temperature of at least about 80° C.
13. The method of claim 12 , wherein the monomer comprises isobornyl (meth)acrylate.
14. The method of claim 12 , wherein the monomer comprises 1,6-hexanediol di(meth)acrylate.
15. The method of claim 1 , wherein the optical element is formed over a substrate surface, said optical element having an optical axis that is non-vertically oriented with respect to the substrate surface.
16. The method of claim 15 , wherein the optical axis is substantially parallel to the substrate surface.
17. A method of fabricating a three dimensional optical element comprising the steps of:
(a) providing a photo-hardenable composition, comprising
(i) a hydrophobic, photodefinable polymer, said photodefinable polymer having a glass transition temperature in the cured state of at least about 80° C., and having a substantially constant index of refraction in the cured state in a temperature range from 0° C. to 80° C.;
(ii) a multiphoton photoinitiator system; and
(b) coating the photo-hardenable fluid composition onto a substrate;
(c) imagewise exposing one or more portions of the coated composition to said electromagnetic energy under conditions effective to photodefinably form at least a portion of a three-dimensional optical element comprising a photoinitiator and a separate photosenitizer.
18. A photodefinable composition that can be imagewise cured using a multiphoton curing technique, said composition comprising:
(a) a hydrophobic, photodefinable polymer, said photodefinable polymer having a glass transition temperature in the cured state of at least about 80° C., and having a substantially constant index of refraction in the cured state in a temperature range from 0° C. to 80° C.; and
(b) a multiphoton photoinitiator system comprising a photoinitiator and a separate photosensitizer.
19. An optical element derived from ingredients comprising an imagewise, photodefined composition, said composition comprising:
(a) a hydrophobic, photodefinable polymer, said photodefinable polymer having a glass transition temperature in the cured state of at least about 80° C., and having a substantially constant index of refraction in the cured state in a temperature range from 0° C. to 80° C.; and
(b) a multiphoton photoinitiator system comprising a photoinitiator and a separate photosensitizer.