Method of making optical films and stacks
Methods of making optical films and optical stacks are described. A method of making an optical lens molded to a first curved optical film includes providing a first optical film including alternating first and second polymeric layers; providing a thermoform tool having a curved surface; heating and conforming the first optical film to the curved surface to form a first curved optical film; and molding an optical lens onto the first curved optical film.
1. A method of making an optical film and lens molded thereto comprising:
providing a first optical film comprising alternating first and second polymeric layers;
providing a thermoform tool having a curved surface;
heating and conforming the first optical film to the curved surface and then releasing the first optical film from the curved surface resulting in a first curved optical film, the first curved optical film being rotationally symmetric about an optical axis, the curved surface being rotationally asymmetric about the optical axis; and
molding a molten optical material onto the first curved optical film resulting in an optical lens molded to the first curved optical film.
2. The method of claim 1 , wherein the molding step comprises molding the optical lens onto a second optical film opposite the first curved optical film.
3. The method of claim 2 , wherein the first curved optical film comprises a reflective polarizer and the second optical film comprises a partial reflector.
4. The method of claim 2 , further comprising the step of thermoforming the second optical film prior to the molding step.
5. The method of claim 1 , wherein the first curved optical film comprises a reflective polarizer.
6. The method of claim 5 , wherein the reflective polarizer comprises at least one layer substantially optically uniaxial at at least one location.
7. The method of claim 5 , wherein the first curved optical film further comprises a retarder.
8. The method of claim 1 , wherein prior to the heating and conforming step, the first polymeric layers are substantially uniaxially oriented and the second polymeric layers are substantially isotropic.
9. The method of claim 1 , wherein the molding step comprises film insert molding.
10. The method of claim 1 , wherein the molding step comprises injection molding.
11. The method of claim 1 , wherein the molten optical material comprises polycarbonate.
12. A method of making an optical film comprising:
providing an optical film;
providing a tool having an external surface having a first shape different than a desired shape, the desired shape being rotationally symmetric about an optical axis, the first shape being rotationally asymmetric about the optical axis;
conforming the optical film to the external surface having the first shape while stretching the optical film along at least orthogonal first and second directions resulting in a conformed optical film having the first shape;
releasing the conformed optical film from the external surface resulting in the optical film having the desired shape.
13. The method of claim 12 , wherein the optical film comprises alternating first and second polymeric layers.
14. The method of claim 13 , wherein prior to the conforming step, the first polymeric layers are substantially uniaxially oriented and the second polymeric layers are substantially isotropic.
15. The method of claim 12 , wherein the optical film having the desired shape is a reflective polarizer comprising at least one layer substantially optically uniaxial at at least one location.
16. The method of claim 12 , further comprising molding a molten optical material onto the optical film having the desired shape.