Abstract: An optical module includes an optical connector element formed of first and second substrates for carrying optical fibers therebetween, and a device substrate carrying photodiodes on an upper major surface thereof in correspondence to the optical fibers, wherein the optical connector element is mounted upon the device substrate such that end surfaces of the first and second substrates face the principal surface of the device substrate and such that polygonal projections provided on the principal surface of the device substrate for positioning engage with corresponding spaces formed between the first and second substrates at the foregoing end surfaces.

Abstract: A method of avoiding phase discontinuities between adjacent sections of a long Bragg grating written section-by-section in an optical fibre uses masks with alignment parts additional to their writing parts. Each alignment part is a replica of a portion of the writing part of the adjacent mask. The writing of the Bragg grating produces an associated absorption grating and so, for light directed in series through the alignment part of the mask and the already-written previous section of the grating, transmission is at a maximum when the mask is moved into exact registry. Fine adjustment of mask position is made to find this condition before writing with this mask is commenced.

Abstract: Fabricated articles of fluoropolymer are foamed by heating the articles to a deformable state, pressurizing the heated article with supercritical CO.sub.2, depressurizing the pressurized heated article while still in the foamable state, whereby said CO.sub.2 foams said article, and cooling the resultant foamed article.

Abstract: Microporous membranes are described and characterized as having a morphological microstructure of very highly elongated nodes interconnected by fibrils which form a structural network of voids or pores through the spaces between the nodes and fibrils, which voids or pores extend from one side of the membrane to the other. The membranes are highly uniform in terms of mass per volume, have very high strength and a very open microstructure.

Abstract: Monoaxially stretched moulded article made of polytetrafluorethylene (PTFE) containing talc and/or mica and/or a high temperature resistant polyimide and/or whiting as filler, and having strength values in the stretching direction of at least 10 cN/tex.The moulded article according to the invention may be formed into dental floss if it contains whiting as filler.

Abstract: A porous plastic filter for separating fine particles, which is obtained by sinter-forming particles of thermoplastic material, wherein the contact angle to water of at least one surface of the porous plastic filter is at least 60.degree., preferably at least 90.degree., and at least a thermoplastic material having an average particle size within a range of from 5 to 90 .mu.m, is used.

Abstract: Expanded graphite sealing rings having particles of PTFE captured at least in a surface layer are disclosed. The sealing rings are produced by impregnating porous rings, cut from a sheet of low density expanded graphite, with a PTFE dispersion and then compressing the rings to a desired final density. Impregnation is accomplished in the presence of an electric field.

Abstract: A composite hollow fiber membrane is provided, which includes a microporous hollow fiber support membrane and a polymeric ultrathin layer formed on the outer surface of the microporous hollow fiber support membrane by interfacial polymerization, and which contains an organic fluorine compound. Also provided is a process for its production, in which a microporous hollow fiber support membrane is successively contacted with first and second solutions involved in the polymerization, but it is further contacted with a third liquid which is substantially immiscible with the first and/or second solutions and which contains an organic fluorine compound, before and/or after contact with the second solution. Thus, it becomes possible to produce a composite hollow fiber membrane exhibiting excellent permeability and selectivity performance in a continuous and stable manner.

Abstract: A method of manufacturing a die for optical elements having a given construction on a relief type grating or the like is disclosed. The method includes the steps of: forming a workpiece film on a substrate; machining the workpiece film in a required configuration; subjecting the workpiece film machined in the required form and the substrate to etching to transfer the configuration of the workpiece film on the substrate analogously in the depth direction; and forming a die by using the etched substrate as a master matrix.

Abstract: A process for spinning a fully water washed fluorinated olefinic polymer intermediate fiber structure from a mixture of an aqueous dispersion of particles of the fluorinated olefinic polymer and a solution of a cellulosic ether.

Abstract: A method and apparatus for releasably securing mold pieces used to mold an artificial eye lens, for example a hydrophilic contact lens. The apparatus includes an ultrasonic welding system to provide directed energy, modified so that the output horn is convex to extend within the outer concave portion of one of the mold pieces and has a shoulder to rest upon the flange of said piece thereby centering it. The method applies directed energy, such as ultrasonic vibrations, through the energy emitter horn to soften or melt then fuse the mating peripheral edge portion of the lens mold pieces.

Abstract: An optical module includes an optical connector element formed of first and second substrates for carrying optical fibers therebetween, and a device substrate carrying photodiodes on an upper major surface thereof in correspondence to the optical fibers, wherein the optical connector element is mounted upon the device substrate such that end surfaces of the first and second substrates face the principal surface of the device substrate and such that polygonal projections provided on the principal surface of the device substrate for positioning engage with corresponding spaces formed between the first and second substrates at the foregoing end surfaces.

Abstract: A gasket for use in sealing sanitary piping comprises an annular plate of porous polytetrafluoroethylene, the inner surface layer of the gasket being heat treated to form a pore-free fused solidified layer for directly contacting a fluid to be sealed. The fused solidified layer prevents osmotic leakage of sealed fluid. Since the solidified layer is formed only in the surface layer the intrinsic properties of porous polytetrafluoroethylene, such as flexibility and affinity, are retained. The gasket is made by inserting a tubular member with an internal heater into a porous polytetrafluoroethylene gasket so that the tubular member directly contacts the inner surface layer of the gasket. The tubular member is operated at a temperature of 420.degree. to 460.degree. C. and contacts a gasket for 10 to 30 seconds to form the fused and pore-free layer.

Abstract: An improved process for forming a thin, durable coating of a perfluorosulfonated, salt- or acid-form ionomer on a selected substrate, which comprises contacting the substrate with an aqueous, surface active dispersion of the thermoplastic, sulfonyl fluoride precursor of the perfluorosulfonated, salt- or acid-form ionomer, contacting the dispersion-wetted substrate with a salt solution or a strongly ionizing acid solution of a sufficient ionic strength to cause a thin, adherent coating of the precursor particles in said dispersion to be formed on the substrate, then removing excess dispersion and excess salt or acid solution, annealing the coated substrate at an elevated temperature and thereafter converting the precursor to the desired acid or salt form ionomer.

Abstract: A method for fabricating domain reversals in predetermined periods without the occurrence of localized variations in refractive index. Localized areas of a unipolarized ferroelectric material which is made of an LiNbO.sub.3 substrate, or the like, and possesses a nonlinear optical effect are exposed to electron beams in a predetermined pattern, so that domain reversals are defined. Thereafter, this ferroelectric material is subjected to a heat treatment at a temperature below the Curie temperature of the ferroelectric material.

Abstract: A process for preparing a dispersion spun fluorinated polymer fiber wherein the intermediate fiber structure, immediately before sintering, contains primarily ions characterized as fugitive ions.

Abstract: A method of molding an aromatic polyimide resin, comprising compression molding an aromatic polyimide resin composition powder comprising an aromatic polyimide resin and a fluorine resin added thereto, and then sintering the compression molded product in a mixed gas atmosphere of oxygen and inert gas, having the oxygen concentration of 0.1 to 10% at 360.degree. to 480.degree. C., or sintering the compression molded product in an inert gas atmosphere and then heat treating the same in a mixed gas atmosphere of oxygen and inert gas at 360.degree. to 480.degree. C. This method can solve the problems on color shade and strength due to sintering in the case of molding an aromatic polyimide resin having a fluorine resin added thereto, and can provide a polyimide molding having excellent quality.

Abstract: A hydrophilic oxygen permeable contact lens having a front surface which is not to be in contact with the cornea of a human eye when the contact lens is worn on the human eye, wherein at least the front surface of the contact lens is coated with a hydrophilicity rendering material which renders the front surface hydrophilic and which is selected from the group consisting of: (A) hydrophilic silicone oil which is represented by the formula given in the specification and whose viscosity at a temperature of 20.degree. C. is not higher than 5,000 centipoise; (B) polysaccharide or its derivative; and (C) denatured collagen whose average molecular weight is in a range of 400.about.100,000. Also disclosed is a method of producing the hydrophilic oxygen permeable contact lens.

Abstract: In the present invention a blend of resin composition and blending technique is optimized to provide a desired balance of node size and fibril length with the additional property of thermal stability in the resulting stretched material.The stretched blend can be described as a polytetrafluoroethylene porous material having a microstructure of nodes interconnected by fibrils in which the material comprises a blend of two different polytetrafluoroethylenes, one polytetrafluoroethylene being a homopolymer of tetrafluoroethylene and the other polytetrafluoroethylene being a modified polymer of tetrafluoroethylene.

Abstract: A method, and an article produced according to the method, for embedding conductors in a structure having a signal distribution function associated therewith such as a vehicle instrument panel. The method includes embedding a conductor in a film, and molding a material to the film such that the material and the film integrally form the structure. The method also includes attaching a connector to the integral structure so that the connector is provided in communication with the conductor.

Abstract: The graphite fiber-reinforced fluororesin composite including 99 to 40 parts by weight of a fluororesin, e.g. polytetrafluoroethylene, and 1 to 60 parts by weight of a graphite fiber. The graphite fiber has a specific surface area of 0.6 to 25 m.sup.2 /g and, as determined by X-ray photoelectron spectroscopic analysis, (1) a surface atomic oxygen/atomic carbon ratio of 0.10 to 0.20, (2) a surface atomic halogen/atomic carbon ratio of 0.05 to 1.8 or (3) a surface atomic oxygen/atomic carbon ratio of 0.10 to 0.20 and a surface atomic halogen/atomic carbon ratio of 0.05 to 1.8. Such fiber may, for example, be obtained by subjecting a graphite fiber to oxidizing treatment, halogenating treatment, or oxidizing and halogenating treatments. The graphite fiber imparts high mechanical strength characteristics and wear resistance to the composite.

Abstract: A process is provided for producing an additive-containing PTFE or other fluorocarbon polymer resin which achieves substantially complete and thorough homogeneous distribution of the selected additive within the polymer matrix. The selected additive and polymer are blended and then subjected to an air milling in an air impact pulverizer to achieve particle to particle impact and the homogeneous distribution of the additive in and among the polymer particles. The milled polymer-additive composite is paste extruded and further processed to form additive-containing PTFE products such as dental floss, insulating or conductive materials, laser markable materials, abrasion resistance materials and the like.

Abstract: Bicomponent moulded article made of polytetrafluoroethylene (PTFE) which, in the manner of the side-by-side type, is composed of two PTFE components which shrink under the effect of heat and differ in their hot-air shrinkage by at least 1%. A preferred embodiment is in the form of a fibre which can be crimped under heat treatment. (FIG.

Abstract: Process for the production of thermoinsulating structural elements, which includes:a)producing by thermoforming a cell made of thermoplastic material;b)pulling on such cell on a male die half shell;c)closing the die with a negative half shell suitable to form a cavity between the half shells,d)inserting in the cavity bored hollow elementse)filling the cavity with foamed pearls in thermoplastic polymers;f)sintering the pearls with steam fed through hollow elements.g)cooling and extracting the hollow elementsh)extracting the structural element from the die.

Abstract: There is provided a polytetrafluoroethylene (PTFE) porous material which has improved adhesion and improved buckling resistance on bending without a tearing problem along a tubular axial direction.The porous material is composed of a polytetrafluoroethylene and a heat-meltable resin of which melting point is lower than that of the polytetrafluoroethylene, has fibril portions and node portions and characterized in that the fibril portions are mainly of the polytetrafluoroethylene, and the heat-meltable resin mainly constitutes the node portions and hardly constitutes the fibril portions.

Abstract: The present invention provides high strength fiber of polytetrafluoroethylene (PTFE) having a strength of at least 0.5 GPa, which is manufactured by forming a monofilament of PTFE group polymer by paste extrusion, free end annealing the monofilament, and subsequently drawing the annealed monofilament to form the fiber, wherein PTFE molecular chains are oriented in a direction parallel to an axial direction of the fiber.

Abstract: Sintering oven utilization is increased by completing the sintering cycle for a molded article of granular polytetrafluoroethylene outside of the oven inside an insulation shell.

Abstract: A substantially cylindrical bar of microporous PTFE is non-fibrillated and incorporates pores within any cylindrical surface within the bar centred about the central longitudinal axis of the bar that are of substantially uniform size and are substantially uniformly distributed within that surface. The process for producing such a bar includes the step of applying a substantially radial compressive force to pre-heated and cooled granules of PTFE and subsequently re-heating and cooling the compressed granules, while a film of non-fibrillated, microporous PTFE is formed from the cooled bar, the plane of the film being perpendicular to the direction of the radial compressive force whereby the pores within any plane substantially perpendicular to the thickness of the film are of substantially uniform size and are substantially uniformly distributed within that plane and all such parallel planes.

Abstract: The present invention provides an optical device comprising: (a) a substrate; and (b) a plurality of units on the substrate. Each of the units comprises a plurality of tapered waveguides wherein: (i) each of the waveguides has a light input surface adjacent the substrate (a) and a light output surface distal from the light input surface and the light input surface area is greater than the light output surface area; (ii) each of the waveguides tapers from its light input surface to its light output surface at an angle; and (iii) at least one of the light input surface area or the light output surface area of at least one of the tapered waveguides is different than the corresponding surface area of the remaining tapered waveguides in the unit. Preferably, the optical device is a viewing film. The present viewing film has reduced or substantially eliminated intensity hot spots and interference patterns.

Abstract: A method for manufacturing light panels consisting of a plate shaped carrier with light conducting fibers fixed therein according to a given pattern. The method includes the steps of inserting the top end of each fiber from a fiber supply through openings in a mold. The mold is then filled with a castable plastic layer which is allowed to set to form a carrier. The carrier retains the fibers with the top ends of the fibers extending above the carrier. The top ends of the fibers extending above the carrier are melted by heat from a laser to form a melted nob at the top end of each fiber to act as a lense. A cover layer is applied on the carrier to embed the top end of each fiber and to protect the carrier. The carrier can be removed from the mold to allow the mold to be refilled with another castable plastic layer to form a next carrier for repeating the process. Removable plugs may be initially inserted into the openings of the mold to facilitate removal of the carrier at a desired angle.

Abstract: A method and apparatus releasably secure mold pieces used to mold an artificial eye lens, for example a hydrophilic contact lens. The apparatus includes an ultrasonic welding system to provide directed energy, modified so that the output horn is convex to extend within the outer concave portion of one of the mold pieces and has a shoulder to rest upon the flange of said piece thereby centering it. The method applies directed energy, such as ultrasonic vibrations, through the energy emitter horn to soften or melt then fuse the mating peripheral edge portion of the lens mold pieces.

Abstract: A process of manufacturing an article having high load absorption, durability and wear resistance properties with increased lubricity including mixing particles of polyurethane and polytetrafluoroethylene, extruding the mixture of polyurethane and polytetrafluoroethylene particles, reducing the extruded polyurethane/polytetrafluoroethylene product to particle form and molding the polyurethane/polytetrafluoroethylene extruded particles to form the article in a selected configuration.

Abstract: A method for improving the radial enlargeability and other properties of tape-reinforced tubular vascular graft formed of sintered fluoropolymer(s), such as expanded, sintered PTFE. Broadly, the method comprises the step of radially shrinking the reinforcement tape layer of the graft, or the entire tape-reinforced graft, after sintering thereof. Such radial shrinkage of the reinforcement tape layer, or of the entire graft, renders the graft subsequently radially enlargeable by more than 5%, without tearing or breaking of the reinforcement tape layer of the graft. Radially enlargeable grafts of the present invention may be combined with various types of stents or anchoring systems, to form endovascular graft devices which are transluminally insertable and implantable within the lumen of a host blood vessel.

Abstract: A dual porosity PTFE tube including an inner surface of expanded PTFE material having a first porosity and an outer surface of expanded PTFE material having a porosity different from that of the inner surface. The preferred method includes the step of forming inner and outer preformed tubular billets of PTFE resin particles mixed with a lubricant; the outer billet is adapted to closely fit around and concentric to the inner billet. Porosity of the inner and outer surfaces is varied by changing, in the respective billets, the lubrication level and/or the PTFE resin characteristic average particle size. The inner billet is placed inside the outer billet, and the two are extruded together, thereby melding the two billets. The extrudate is then longitudinally expanded and sintered. The inner surface of the resulting PTFE tube exhibits a different porosity than the outer surface of the tube; the porosities of the inner and outer surfaces are both within a range of about 0.10-200 .mu..

Abstract: A process and an apparatus for producing a preform for plastic optical fiber having a refractive index distribution in which the refractive index is gradually decreased from the center of the preform toward the outer periphery thereof, by depositing a deposition layer comprising a polymer A (refractive index: N.sub.a) and a refractive index modifier having a refractive index different from that of the polymer A onto a surface of a rod member rotating about an axis thereof, by use of vapor-phase deposition based on a CVD (Chemical Vapor Deposition) process, or a coating process. A plastic optical fiber preform comprising deposition layers having a gradually decreasing refractive index distribution is formed by changing the mixing ratio between the polymer A and the refractive index modifier constituting the deposition layer.

Abstract: A method is provided for creating a plastic component constructed, at least in part, from polychlorotrifluoroethylene, having improved properties. The method creates a component from a composition that has polychlorotrifluoroethylene, heats the component to a temperature that is greater than the melting point of the composition, and rapidly quenches the component in a cold medium.

Abstract: Optical waveguides are produced in laser densified Type VI porous gel-silica. A CO.sub.2 laser directly scans the substrate having a pore size of about 30 angstroms. Tracks having a width of about 50 microns are produced.

Abstract: A method for reducing discoloration in a discolored plastic material which has been subjected to sterilization by gamma radiation which includes exposing the plastic material to light having a wavelength within the range of 200 to 600 nm for a time sufficient to restore the original clarity. A sterilized pack for a medical device including plastic material in which the clarity has been restored by the method is also included.

Abstract: A process for producing a preform for plastic optical fiber having a refractive index distribution in which the refractive index is gradually decreased from the center of the preform toward the outer periphery thereof, by depositing a deposition layer comprising a polymer A (refractive index: N.sub.a) and a refractive index modifier having a refractive index different from that of the polymer A onto an inner surface of a hollow cylindrical member rotating about an axis thereof, by use of vapor-phase deposition based on a CVD (Chemical Vapor Deposition) process, or a coating process. A plastic optical fiber preform comprising deposition layers having a gradually increasing refractive index distribution is formed by changing the mixing ratio between the polymer A and the refractive index modifier constituting the deposition layer.

Abstract: A molded article of fluorine-containing polymer, especially of polytetrafluoroethylene, with increased water-repellency, and a jig for holding articles to be washed during washing processes using an aqueous washing medium. The molded article with superior water-repellency can be obtained by a treatment of the surface of fluorine-containing polymer with a fluorine-containing gas after roughening of the surface. The water-repellent jig made of the surface treated polytetrafluoroethylene is suited for use as a carrier for washing semi-conductor wafers and glass plates or guide rolls of a liquid crystal display device.

Abstract: A method and apparatus releasably secure mold pieces used to mold an artificial eye lens, for example a hydrophilic contact lens. The apparatus includes an ultrasonic welding system to provide directed energy, modified so that the output horn is convex to extend within the outer concave portion of one of the mold pieces and has a shoulder to rest upon the flange of the one piece thereby centering it. The method applies directed energy, such as ultrasonic vibrations, through the energy emitter horn to soften or melt then fuse the mating peripheral edge portion of the lens mold pieces.

Abstract: Methods, and various apparatus therefor, are disclosed for the electrolytic treatment of an acidic solution. Generally the method comprises: (a) providing an electrolytic cell, the cell comprising: (i) an anode chamber and an anode therein; (ii) a cathode chamber and a cathode therein; and (iii) a diaphragm. Usually the diaphragm is of a non-isotropic fibrous mat comprising 5-70 weight percent organic halocarbon polymer fiber in adherent combination with about 30-95 weight percent of finely divided inorganic particulate impacted into said fiber during fiber formation, the diaphragm having a weight per unit of surface area of about 3-12 kilograms per square meter. The method can continue by (b) introducing the acidic solution into the cell; (c) impressing a current on the anode and the cathode causing the migration of ions through the diaphragm; and (d) recovering a product of the electrolytic treatment from the anode chamber, or the cathode chamber, or from both chambers.

Abstract: A method for preparing thin fluoropolymer (PTFE) films, said method generally having the steps of: a) providing an unsintered fluoropolymer film; b) pre-sintering expansion of the film; c) sintering the expanded film with dimensional restraint to prevent shrinkage; and d) post-sintering stretching of the film to a final thickness preferably less than 0.002 inches. The post-sintering stretching of the film in step d may be accomplished in a single step, or may include a series of post-sintering stretching steps. Steps b and c of the method may be carried out bypassing the calendared film through a machine direction orienter device and, thereafter, step d of the method may be accomplished by subsequently repassing the sintered film through the machine direction orienter device, one or more additional times.

Abstract: In a method for the manufacture of plastic parts which are used in an analytical measuring device and there come into contact with liquids, plastic base material is mixed with a suspension liquid and then extruded in the form desired. Before it is mixed with the plastic base material, aromatic and olefinic substances are removed from the suspension liquid by means of a chemical reaction, for instance, so that the final plastic products are free from such substances. In that way, it is avoided that, when using the plastic parts in an analytical measuring device, it may come to interferences of the detection by extraction of such substances into the flow of liquids and transportation into the detector. A vacuum degasser is a particularly advantageous field of application for the plastic parts manufactured in accordance with the invention.

Abstract: A method of forming an optical element on the surface of a substrate by ejecting a curable light guide forming liquid from a nozzle onto the substrate and curing the curable light guide forming liquid. A waveguide may be formed by moving the nozzle in a linear pattern over the surface of the substrate during ejection of the liquid from the nozzle. Curing the liquid may include exposing the liquid to ultraviolet radiation, and the radiation may be applied to only a small portion of the liquid. A multilayered waveguide may be formed by ejecting a further light guide forming liquid onto the first and curing it. A core and cladding may be formed simultaneously by ejecting core forming liquid from an inner tube and cladding forming liquid from an annulus about the inner tube. The waveguide may be formed in a groove, and a splitter may be formed by branching a second waveguide from a first, or by laying out two parallel waveguides and connecting them.

Abstract: The invention relates to a hollow body made of fluoro resin, especially of PTFE, obtained by paste extrusion, exhibiting an anisotropy ratio lower than 1 and substantially equal to 0.5. For the manufacture of such hollow bodies a fluoro resin powder, especially unsintered PTFE, is mixed with lubricant, the mixture is compressed to obtain an isotropic compact tubular preform, the preform is introduced into an extrusion press, the preform is expelled through a passage of small cross-section of a die so as to form lengthwise-oriented fibers, the fibers are compressed at the exit of the passage in an internal expansion chamber of enlarged cross-section, so as to orient the fibers transversely, and the fibers are expelled through the exit orifice of the die to obtain a hollow body.

Abstract: A substantially cylindrical bar of microporous PTFE is non-fibrillated and incorporates pores within any cylindrical surface within the bar centred about the central longitudinal axis of the bar that are of substantially uniform size and are substantially uniformly distributed within that surface. The process for producing such a bar includes the step of applying a substantially radial compressive force to pre-heated and cooled granules of PTFE and subsequently re-heating and cooling the compressed granules, while a film of non-fibrillated, microporous PTFE is formed from the cooled bar, the plane of the film being perpendicular to the direction of the radial compressive force whereby the pores within any plane substantially perpendicular to the thickness of the film are of substantially uniform size and are substantially uniformly distributed within that plane and all such parallel planes.

Abstract: A method for increasing the adhesion of a first layer comprising fluoroplastic to a second layer containing a peroxide-curable hydrocarbon elastomer is disclosed. The method involves adding a primary-amine containing unsaturated compound or polymer of less than 10,000 molecular weight to the hydrocarbon elastomer layer.

Abstract: An improved extrusion method is employed in a process which is used to form tubing for medical applications. The method includes providing an extrusion apparatus having a die which includes a die cavity and a mandrel within the die cavity. The die is rotated in a first rotational direction while the mandrel is rotated in a second rotational direction opposite the first direction. While the die and the mandrel are rotating, a PTFE paste is passed through the annular passage defined between the die and the mandrel. The die cavity is cooled to maintain the PTFE paste passing therethrough at a substantially non-elevated temperature.

Abstract: A laser markable composite material which when so marked retains good color contrast after heat aging. The material comprises polytetrafluoroethylene resin, photosensitive filler material and an extrusion aid. The photosensitive material is preferably a metal oxide and has a larger mean particle size than typical pigments. Also disclosed is a sequence of milling, mixing and blending steps which forms the desired composite material.