Patent Number: 
Section: claims

1. An apparatus for decreasing the birefringence of at least one starting halogenated optical material comprising:a chamber for providing an exposure atmosphere,a support member located within said chamber for supporting at least one starting halogenated optical material under tensile stress;a source having a cathode and an anode for providing a large area electron beam within the chamber, said large area electron beam irradiating said at least one starting halogenated optical material under tensile stress, andcontrol means to control the large area electron beam to decrease the birefringence of said at least one starting halogenated optical material under tensile stress. 2. The apparatus for decreasing the birefringence of at least one starting halogenated optical material of claim 1 further comprising:heating means to raise the temperature of said at least one starting halogenated optical material under tensile stress during said large area electron beam irradiating said at least one starting halogenated optical material under tensile stress. 3. The apparatus for decreasing the birefringence of at least one starting halogenated optical material of claim 2 wherein said heating means is located within said chamber. 4. The apparatus for decreasing the birefringence of at least one starting halogenated optical material of claim 2 wherein said heating means can raise said temperature of said at least one starting halogenated optical material under tensile stress to between 10 degrees Celsius and 1000 degrees Celsius during said large area electron beam irradiating said at least one starting halogenated optical material under tensile stress. 5. The apparatus for decreasing the birefringence of at least one starting halogenated optical material of claim 1 further comprising:an aperture mask for limiting said large area electron beam irradiating said at least one starting halogenated optical material under tensile stress to a selected area on said at least one starting optical material under tensile stress. 6. The apparatus for decreasing the birefringence of at least one starting halogenated optical material of claim 5 wherein said aperture mask forms a pattern to the birefringence in said starting halogenated optical material under tensile stress. 7. The apparatus for decreasing the birefringence of at least one starting halogenated optical material of claim 1 further comprising:an embossing structure for limiting said large area electron beam irradiating said at least one starting halogenated optical material under tensile stress to a selected area on said at least one starting optical material under tensile stress. 8. The apparatus for decreasing the birefringence of at least one starting halogenated optical material of claim 7 wherein said embossing structure forms a pattern to the birefringence in said starting halogenated optical material under tensile stress. 9. The apparatus for decreasing the birefringence of at least one starting halogenated optical material of claim 1 wherein the atmosphere in said chamber is between 1 milliTorr and 760 milliTorr. 10. The apparatus for decreasing the birefringence of at least one starting halogenated optical material of claim 1 wherein said at least one starting halogenated optical material is a mixture of at least two different halogenated optical materials. 11. The apparatus for decreasing the birefringence of at least one starting halogenated optical material of claim 1 further comprising:said large area electron beam irradiating a first sub-layer of said at least one starting halogenated optical material under tensile stress, andcontrol means to control the large area electron beam to decrease the birefringence of said first sub-layer of said at least one starting halogenated optical material under tensile stress with the remaining second sub-layer of said at least one starting halogenated optical material retaining its original birefringence. 12. The apparatus for decreasing the birefringence of at least one starting halogenated optical material of claim 11 wherein said large area electron beam partially penetrates said at least one starting halogenated optical material to form said first sub-layer. 13. A method for decreasing the birefringence of at least one starting halogenated optical material comprising:placing said at least one starting halogenated optical material under tensile stressirradiating said at least one starting halogenated optical material under tensile stress with a large area electron beam source, andcontrolling the energy of the electron beam source to decrease the birefringence of said at least one starting halogenated optical material under tensile stress. 14. The method for decreasing the birefringence of at least one starting halogenated optical material of claim 13 further comprising the step of:heating said at least one starting halogenated optical material under tensile stress during said irradiating said at least one starting halogenated optical material under tensile stress. 15. The method for decreasing the birefringence of at least one starting halogenated optical material of claim 14 wherein said heating can raise said temperature of said at least one starting halogenated optical material under tensile stress to between 10 degrees Celsius and 1000 degrees Celsius during said irradiating said at least one starting halogenated optical material under tensile stress. 16. The method for decreasing the birefringence of at least one starting halogenated optical material of claim 13 further comprising the step of:masking said at least one starting halogenated optical material under tensile stress to limit said irradiating said at least one starting halogenated optical material under tensile stress to a selected area on said at least one starting halogenated optical material under tensile stress. 17. The method for decreasing the birefringence of at least one starting halogenated optical material of claim 16 wherein said masking is done by an aperture mask. 18. The method for decreasing the birefringence of at least one starting halogenated optical material of claim 17 wherein said masking is done by an embossing structure. 19. The method for decreasing the birefringence of at least one starting halogenated optical material of claim 13 wherein the atmosphere during said irradiating said at least one starting halogenated optical material is between 1 milliTorr and 760 milliTorr. 20. The method for decreasing the birefringence of at least one starting halogenated optical material of claim 13 further comprising the step of:forming in said at least one starting halogenated optical material a decreased birefringence by creating additional bond structure in said at least one starting halogenated optical material under tensile stress. 21. The method for decreasing the birefringence of at least one starting halogenated optical material of claim 13 wherein said at least one starting halogenated optical material is a mixture of at least two different halogenated optical materials. 22. The method for decreasing the birefringence of at least one starting halogenated optical material of claim 13 whereinirradiating a first sub-layer of said at least one starting halogenated optical material under tensile stress with a large area electron beam source, andcontrolling the energy of the electron beam source to decrease the birefringence of said first sub-layer of said at least one starting halogenated optical material under tensile stress with the remaining second sub-layer of said at least one starting halogenated optical material retaining its original birefringence. 23. The method for decreasing the birefringence of at least one starting halogenated optical material of claim 22 wherein said large area electron beam partially penetrates said at least one starting halogenated optical material to form said first sub-layer.