Low birefringent thermoplastic lenses and compositions useful in preparing such lenses

• Main Authors: HAHN, STEPHEN F, DIEHL, CHARLES F, ZHOU, WEI-JUN, KOPPI, KURT A
• Format: Patent
• Language: Chinese; English
• Published: 16.08.2009
• Subjects: CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCESIN A PLASTIC STATE; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

A lens-forming thermoplastic composition of matter has a crystallinity, as determined in accord with differential scanning calorimetry of from 0 percent to less than 1 percent when the composition comprises a hydrogenated vinyl aromatic/isoprene block copolymer or a crystallinity, as determined in accord with differential scanning calorimetry of from more than 0 percent to less than 1 percent when the composition comprises a hydrogenated vinyl aromatic/butadiene block copolymer. The composition has a birefringence, measured at a wavelength of 633 nanometers, within a range of from 0 to less than 6 x 10-6. Molding a melt of these compositions occurs at temperatures within a range from the hydrogenated block copolymer's glass transition minus 20 DEG C to the glass transition temperature minus 90 DEG C. The compositions suitably form lenses such as an optical pick-up lens, which may be aspherical or have at least one of an irregular surface configuration, a non-uniform thickness or an irregular and non-uniform c