Abstract: A method for reducing the density of sites on the surface of fused silica optics that are prone to the initiation of laser-induced damage, resulting in optics which have far fewer catastrophic defects, and are better capable of resisting optical deterioration upon exposure to a high-power laser beam.

Abstract: A method for reducing the density of sites on the surface of fused silica optics that are prone to the initiation of laser-induced damage, resulting in optics which have far fewer catastrophic defects, and are better capable of resisting optical deterioration upon exposure to a high-power laser beam.

Abstract: A metal halide arc tube is provided having a light-transmitting envelope and electrodes for generating an arc discharge within a sealed chamber of the envelope. The envelope includes a transparent film at a cold region of the sealed chamber where metal halides migrate and condense. The transparent film transmits visible radiation and absorbs ultraviolet radiation emitted by the arc to impose an additional heat load on the cold region so that a high metal halide vapor pressure can be maintained. The temperature of a hot region of the envelope can be maintained at a lower level by reducing power input or increasing chamber surface area. Preferably, the transparent film reflects infrared radiation emitted by the light source back to the arc to increase efficiency and further increase the temperature of the cold region due to decreased thermal emittance. The transparent film is preferably a dichroic coating having alternating layers of high and low index of refraction refractory materials.

Abstract: A light-scattering coating comprising light-scattering particles, such as alumina, dispersed in a silica matrix is formed by applying to the filter a silicone solution in which is dispersed colloidal silica and the light-scattering particles to a suitable substrate and then pyrolyzing the dispersion at high temperature to drive off the organic components and form the silica matrix. This coating is hard and abrasion resistant and is useful for reflectors, lamps and lenses.

Abstract: An interference filter or coating is provided in a predetermined pattern on a lamp envelope. The coating is comprised of alternating layers of high and low index of refraction materials applied to a vitreous outer surface of a lamp envelope. The coating may be geometrically symmetric or asymmetric, continuous or discontinuous with respect to the coating itself or the envelope to which it has been applied. The envelope can be masked prior to deposition of the coating so that removal of the mask leaves the filter in the desired pattern. The preferred process for forming the coating includes forming a boric oxide mask on a portion of the envelope, applying the coating over the mask and removing the coating from masked areas of the envelope by dissolving the mask in an aqueous solution.

Abstract: A lamp-to-light guide coupling arrangement includes an electrodeless high intensity discharge lamp comprising an arc tube with an ionizable fill, and an excitation circuit for electrically exciting the ionizable fill to induce therein a light-producing arc discharge. The coupling arrangement further includes a coupling device comprising a generally tubular, hollow body that has an inlet end for receiving light from the arc discharge and a larger, outlet end. The coupling device further comprises an interiorly directed reflector on a surface of the hollow body for reflecting visible light. Such coupling device is shaped so as to receive light at one solid angle over an area of the inlet end and to transmit light at a smaller solid angle but over a larger area of the outlet end. The coupling device is preferably formed from dielectric material. The reflector preferably comprises a refractory optical interference filter.

Abstract: Incandescent lamps or arc lamps having an infrared red reflecting multilayer optical interference filter on the outer surface of the vitreous or fused quartz lamp envelope enclosing the filament have a light-scattering coating applied over the filter to scatter light emitted by the lamp and thereby diffuse the filament image. The light-scattering coating consists of light-scattering particles, such as alumina, dispersed in a silica matrix. This coating is formed by applying to the filter a silicone solution in which is dispersed colloidal silica and light-scattering particles and pyrolyzing at high temperature to drive off the organic components and form the silica matrix.

Abstract: An electric lamp includes a sealed outer envelope, an arctube located within the envelope, a shroud separate from the arctube having an ellipsoidally-shaped reflecting portion positioned around the arctube, and a coating disposed on the reflecting section of the shroud for reflecting light having predetermined wavelengths emitted by the arctube. The ellipsoidal shape of the shroud is effective for reflecting the light substantially back toward the arctube. Particularly when the coating is a color correcting coating, the shape of the reflecting section is tailored to maximize reflection of radiation at selected wavelengths back toward the arc of the arctube.

Abstract: An interference filter or coating is provided in a predetermined pattern on a lamp envelope. The coating is comprised of alternating layers of high and low index of refraction materials applied to a vitreous outer surface of a lamp envelope. The coating may be geometrically symmetric or asymmetric, continuous or discontinuous with respect to the coating itself or the envelope to which it has been applied. The envelope can be masked prior to deposition of the coating so that removal of the mask leaves the filter in the desired pattern. The preferred process for forming the coating includes forming a boric oxide mask on a portion of the envelope, applying the coating over the mask and removing the coating from masked areas of the envelope by dissolving the mask in an aqueous solution.

Abstract: An electric lamp is provided having a quartz envelope and a light source capable of generating light within the envelope. Disposed on a surface of the envelope is a filter which absorbs a portion of the light emitted by the light source to produce light output poorly seen by insects. The filter includes a blue absorbing pigment in a vitreous glassy silica binder derived from a coating precursor comprising a liquid dispersion of colloidal silica in a silicone. The blue absorbing pigment is preferably a praseodymium doped zircon or an antimony doped nickel titanate. Preferably, the filter also includes a precoat of ultra-fine titania to improve the reduction of ultraviolet radiation.

Abstract: Fused quartz containing europium oxide, titanium dioxide and cerium oxide has been found to be effective for absorbing UV radiation while transmitting visible light radiation. Uses for this material include lamp envelopes and shrouds for halogen-incandescent lamps and metal halide arc discharge lamps which emit both UV and visible light radiation.

Abstract: An optical interference filter produced on a vitreous, light transmissive substrate, such as an electric lamp envelope, includes a plurality of alternating layers of tantala and silica in which each tantala layer includes titania in an amount of less than about 10 mole % whereby the microstructure of the tantala layers is controlled during subsequent crystallization and extrinsic stress in the tantala layers is reduced. Rather than or in addition to including titania in each tantala layer, the present invention additionally contemplates placing at least some of the tantala layers in contact with a titania layer (pre-layer and/or post-layer) whereby the microstructure of the tantala layers is controlled during subsequent crystallization and extrinsic stress in the tantala layers is reduced.

Abstract: The subject invention, therefore, relates to a multi-layer coating for use on a thick-walled metal halide lamp which emits visible light radiation and absorbs and reflects UV radiation, and which further manages the thermal non-uniformity problems across the thickness of the arc tube to substantially eliminate devitrification problems.

Abstract: An electric lamp, such as an incandescent linear quartz heat lamp, is provided having a vitreous light transmissive envelope having an exterior surface and a light source capable of generating light within said envelope. Disposed on a portion of the exterior surface of the envelope is a diffuse reflective coating, such as a boron nitride coating, for reflecting at least a portion of the light emitted by the source. A protective silica coating encapsulates the reflective coating to protect the reflective coating from things such as abrasion, moisture, and cleaning solvents.

Abstract: A light source includes an integral reflective coating on a portion of its envelope for reflecting light back through the source. The light from the source is directed by a reflector toward a focus thereof at which is located an input end of a light guide. The integral reflective coating allows a half ellipsoidal reflector to be used in one embodiment without depreciable loss of light. Accordingly, a pair of light sources can be arranged with a common focus to substantially double the brightness in the light guide. Alternatively, the light sources can provide a primary and redundant arrangement, or used to provide two levels of light in another arrangement. According to another embodiment, a hemispherical reflector is used to obtain unit magnification and increase the angular range through which light may enter the light guide.

Abstract: An optical interference filter produced on a vitreous, light transmissive substrate, such as an electric lamp envelope, includes a plurality of alternating layers of tantala and silica in which each tantala layer includes titania in an amount of less than about 10 mole % whereby the microstructure of the tantala layers is controlled during subsequent crystallization and extrinsic stress in the tantala layers is reduced. Rather than or in addition to including titania in each tantala layer, the present invention additionally contemplates placing at least some of the tantala layers in contact with a titania layer (pre-layer and/or post-layer) whereby the microstructure of the tantala layers is controlled during subsequent crystallization and extrinsic stress in the tantala layers is reduced.

Abstract: A multilayer optical interference filter having a controlled degree of diffuse reflection over a desired visible wavelength range, includes alternating layers of at least one high refractive index material and at least one low refractive index material, wherein at least one layer of the alternating layers is a light scattering layer comprised of titania which diffusely reflects light over a desired visible wavelength range. The multilayer optical interference filter may be provided by a process including sequentially applying the alternating layers by chemical vapor deposition from respective precursors at temperatures effective to pyrolytically decompose the respective precursors, wherein the precursor of the light scattering layer comprised of titania is at least one branched alkoxide of titania.

Abstract: Electric lamps having molybdenum metal parts exposed to an oxidizing environment can withstand exposure to higher operating temperature if the molybdenum metal parts are coated with silicon nitride (Si.sub.3 N.sub.4). Tungsten-halogen lamps having molybdenum outer leads coated with silicon nitride have operated for over 1500 hours at about 450.degree. C. without oxidation failure of the leads.

Abstract: Reflector lamps having vitreous, light transmissive reflectors and containing a source of visible and UV light radiation produce little or no UV radiation in the projected light beam by having a light reflecting coating on the exterior surface of the reflector and the reflector made of UV absorbing glass or having a UV absorbing coating disposed between the light reflecting coating and the exterior reflector surface. An anti-reflecting coating disposed on the interior, light-receiving surface of the reflector reduces UV emission still further.

Abstract: Fluorescent lamps having a tin oxide layer protected by a layer of colloidal alumina having a median particle diameter below 0.4 micron exhibit an objectionable pearlescent coloration if the alumina layer thickness is within the range of 500-8,000 .ANG.. This coloration is reduced to an acceptable level by incorporating from 10-30 wt. % of particulate alumina having a median diameter above 0.75 micron in the colloidal alumina.