Abstract:
An ophthalmic glass lens having a compressively stressed surface zone after ion exchanging which is at least 60 micrometers in depth can be formed from an alkali metal oxide silicate glass comprising by weight about 4 to about 15 percent sodium oxide, about 3 to about 15 percent potassium oxide provided the total amount of sodium, potassium and other alkali metal oxides is up to about 20 percent and about 3 to about 15 percent lanthanum oxide. The ion exchange process can take place at a temperature either above or below the strain point of conventional ophthalmic crown glass to produce satisfactory physical properties in the ophthalmic glass lens.
Abstract:
A method of treating ophthalmic quality lenses or lens blanks that produces a reversible progressive local variation in phototropic behavior with a continuous variation in transmissivity. The lens or lens blank is composed of a potentially phototropic glass containing all the necessary ingredients including uniformly dispersed silver halide particles therein to develop a phototropic behavior during the heat treatment of the present method. The steps of the present method include mounting the lens or lens blank in carrier means, heating the lens or lens blank thus mounted in a heat treatment furnace at a temperature sufficient to develop the phototropic behavior of the potentially phototropic glass. Characteristically the required heat treatment temperature to develop this phototropic behavior is one which exceeds the strain point of the glass but not the softening point thereof. The heat treatment includes the further step of maintaining selected portions of the lens or lens blank at a temperature to substantially inhibit the development of the phototropic behavior and thus produce a progressive gradient of transmissivity. The particular improvement of the present invention includes heat sinking the selected portion of the lens to be maintained at a temperature which substantially inhibits the development of phototropic behavior by utilizing the latent heat of transformation of a material which has at least one phase transformation temperature below the temperature required for development of phototropic behavior. This heat sinking is accomplished by positioning the heat sinking material proximate to the portion of the lens or lens blank in which the temperature is to be maintained to substantially inhibit the development of phototropic behavior. This is preferably accomplished by establishing a path of heat conduction between the heat sinking material and the selected portion of the lens or lens blank.
Abstract:
The invention achieves local variation, or a continuous gradation, in photochromic or phototropic properties across the face of glass lenses and lens blanks, especially those of ophthalmic quality. The lenses and lens blanks contain all those ingredients required to produce photochromic or phototropic behavior. They are exposed to a locally variable temperature field or environment, in such manner as to, in at least one portion of the lens or lens blank cause the temperature therein to exceed the strain point but not the softening point of the glass. In other portions of the lens or lens blank the temperature is below the strain point, thus causing development of phototropic or photochromic behavior only in those portions of the lens or lens blank exposed to the temperatures above the strain point.
Abstract:
A laminated optical or ophthalmic element is produced comprised of an amorphous and/or crystalline material possessing phototropic or photochromic properties as a result of applying a thin layer over at least one surface thereof, which layer includes a combination of cations and anions including silver or copper bromide and/or chloride.
Abstract:
Making perforate optical sections (lenses) of pseudophakoi with avoidance of drilling operations and adversities thereof. Lens material is cast over wires corresponding in diametral size and relative juxtaposition to the size and spaced locations of holes needed in a lens and the wires are etched away prior to or following final edging and surface finishing of the lens. The casting of multiple lens preforms is contemplated.
Abstract:
An ophthalmic glass lens can be prepared by exposing an alkali metal silicate glass to an ion exchange process in which the glass is chemically strengthened by an exchange of potassium ions for sodium ions in the surface layer of the lens at a temperature either above or below the strain point of the glass. The glasses prepared are essentially free of alumina, have adequate strength and substantially increased depth of pentration of the neutral zone even when up to about 6 percent lime is utilized in the preparation of the glass. The effect of lime as a diffusion-retarding agent during the ion exchange process can be overcome (1) by use of an appropriate amount of zinc or magnesium oxide or mixtures thereof so as to maintain an adequate rate of diffusion during ion exchange or (2) by preparation of the glass essentially free of alumina.
Abstract:
Faraday rotation glasses exhibiting a high Verdet constant and a low susceptability toward devitrification are formed by introducing a high quantity of rare earth oxides into a borate glass base. The glasses can be melted under standard environmental conditions and may be made on a large scale.
Abstract:
A connector 1 for an optical fiber 2 comprising, an alignment body 3 and a length of optical waveguide 4 drawn into a unitary structure 18, and, while the length of optical waveguide 4 is unitary with the alignment body 3, the length of optical waveguide 4 is shortened by etching or abrading to provide a passage 5 in the alignment body 3 for receiving an external optical fiber 2 for coupling with the length of optical waveguide 4.
Abstract:
Apparatus for supporting a lens during heat treatment that has a heat-sinking material in contact with one side of a heat-conductive cover and the other side of the heat-conductive cover in contact with a portion of a lens being treated to produce photochromic behavior is disclosed. The portion of the lens in contact with the heat-conductive cover exhibits less photochromic activity than the portion of the lens which is not in contact with the heat-conductive cover.
Abstract:
A process for producing a photochromic silicate glass film is disclosed which is characterized by the steps of forming a solution containing silver ions and a film-forming silicate monomer in a solvent common to both, removing the solvent from the solution to produce a discreet film or a film coating on an article, and exposing the formed film to a source of halide ions to form fine silver halide particles within the film.