This technology is available from Temarex Corporation.

OPTICAL AND/OR BIREFRINGENT POLYMERS

 

Title:NEGATIVE BIREFRINGENT RIGID ROD POLYMER FILMS

Inventor(s):F. Harris, S.Z. Cheng

Disclosure 244 U.S. Patent 5,580,950

This invention relates to a class of soluble polymers having a rigid rod backbone, which when used to cast films, undergo a self-orientation process whereby the polymer backbone becomes more or less aligned parallel to a film surface.This in-plane orientation results in a film that displays negative birefringence.The degree of in-plane orientation and thus, the magnitude of the negative birefringence is controlled by varying the backbone linearity and ridigity of the class of polymers through selection of substituents in the polymer backbone chain. By increasing the polymer backbone linearity and rigidity, the degree of in-plane orientation and associated negative birefringence can be increased, and that conversely, by decreasing the polymer backbone linearity and rigidity, the negative birefringence can be decreased.

A negative birefringent film can be prepared from a rigid rod wherein the polymer is selected from the group consisting of polyamide, polyester, poly(amide-imide) and poly(ester-imide).

These films are equally applicable to liquid crystal displays which have either active or passive display areas, as well as both active and passive display areas.This invention is applicable to reflective as well as transmissive type liquid crystal displays.

Advantages of these films are (1) enhanced viewing properties of a LCD over a wide range of viewing angles, (2) that customization to a desired negative birefringent value can be achieved, (3) one does not need to resort to the use of stretching to achieve the desired orientation, and (4) films need not be comprised of an inorganic birefringent crystal, such as sapphire.

 

Title: ORGANIC AND TRANSPARENT NONLINEAR OPTIC (NLO) POLYMERS

Inventor(s):W. Brittain, J. Kulig, C. Moore

Disclosure 223 U.S. Patent 5,405,926

The objectives of this invention are to provide (1) a solvent free polymerization process, via a low viscosity prepolymer stage which may enhance electric field poling of materials, (2) polymers having asymmetric charge distribution, (3) polycarbonate and polyether polymers which exhibit nonlinear optical responses, (4) a new process for the synthesis of a polycarbonate polymer having highly polarizable -electron systems, (5) a method to make a polymer material which has a non-centric alignment and which has a relatively high orientation stability, and (6) laminates incorporating the NLO polymers and suitable substrates.

This technology is ideally suitable for fabricating films for devices which contain polymeric NLO components such as a laser frequency converter, optical Pockels effect device, optical Kerr effect device, degenerate four wave mixing device, optical interferometric waveguide gate, wide-band electro optical guided wave analog-to-digital converter, all-optical multiplexer or demultiplexer, optical bi-stable device, an optical parametric device, or the like.

 

Title:NON-BIREFRINGENT OPTICAL ADHESIVES, FILMS, AND SUBSTRATES

Inventor(s):T. Kyu

Disclosure 214 U.S. Patent Notice of Allowance

This invention relates the development of birefringence-free optical adhesives and films using a birefringence compensation technique.Most polymers are optically anisotropic because of the nature of the long macromolecular chains.Depending on the chemical structure, a macromolecule could have a positive or negative birefringence.Polymers with aromatic compounds in the main chain generally have positive birefringence due to large polarizability along the chain axis compared with that in the transverse direction.Polymers are subject to flow during extrusion or molding; therefore, the end product is often highly birefringent due to chain orientation and residual stress.This induced birefringence causes undesirable effects in many optical applications such as laser disks, electronic devices, etc.

To minimize the birefringence of polymeric films and adhesives, it is customary to blend polymers with opposite anisotropy.However, the polymer pairs must be completely miscible, which is extremely difficult, if not impossible, to achieve.This invention has successfully demonstrated that positive polarizability of polycarbonate (PC) can be compensated by blending with negatively birefringent polyphenylmethacrylate (PPMA).This polymer pair is completely miscible.

This invention also discloses that some thermoset/thermoplastic blends are completely miscible before and after curing; thus these blends may be used as non-birefringent adhesives.One of the functionalized thermoset/thermoplastic blends exhibit true miscibility and the refractive indices can be varied from 1.49 to 1.58.The refractive index of this blend can, therefore, be matched with the refractive index of many substrates including glasses.The pot-life of the adhesive varies from a few days to a week, depending on formulation.

This invention also covers synthesized and formulated non-birefringent optical adhesives through copolymerization of functional monomers.

 

Title:NEGATIVE BIREFRINGENT POLYIMIDE FILM

Inventor(s):F. Harris, S. Z. Cheng

Disclosure 212(a) U.S. Patent 5,344,916 Disclosure 212(b)-CIP U.S. Patent 5,480,964

A method for controlling the negative birefringence of a polyimide film which allows the matching of an application to a targeted amount of birefringence by controlling the degree of in-plane orientation of the polyimide by a selection of functional groups within both the diamine and dianhydride segments of the polyimide which affect the polyimide backbone chain rigidity, linearity, and symmetry.The higher the rigidity, linearity and symmetry of the polyimide backbone, the larger the value of the negative birefringence of the polyimide film.

 

Title:POLYMERIC NETWORKS OF POLYSILOXANE WITH INCREASED MODULUS

Inventor(s):V. Galiatsatos, P. R. Subramanian

Disclosure 194 U.S. Patent 5,376,738

The objective of this invention is to make polysiloxane networks of higher modulus without resorting to adding proportionately more short chain polysiloxanes and without adding reinforcing fillers. Thus, new networks with increased modulus and without the need of a particulate filler while maintaining reinforcement and transparency properties have been developed.

A method for making polyorganosiloxane networks with controlled heterogeneity of the molecular weight between crosslinks.Low molecular weight polyorganosiloxane are reacted with a polyfunctional crosslinking agent to form a product of higher molecular weight than that of the starting materials.These partially crosslinked chains are then reacted with more crosslinking agents and polyorganosiloxane with higher molecular weights.The molecular weight achieved in the first reaction has an effect on the properties such as modulus, birefringence, and stress optical coefficient.The low molecular weight chains in this form serve to increase modulus and durability while keeping optical clarity of the inherently soft networks.

These networks are ideally suitable for gaskets, sealants, caulks, optical windows, and molded parts where high modulus and/or controllable birefringence are required.