Abstract: A lamp inlead assembly for a light source having a lamp envelope with at least one end region in which the lamp inlead assembly is sealably disposed includes and outer lead wire member to which power to the light source is coupled, an inner lead wire member to which the light generating device is connected, whether incandescent or discharge, and a thin foil member disposed therebetween on which the inner and outer lead wire members are fixedly secured. The thin foil member is constructed of molybdenum and is essentially uniform in thickness throughout.

Abstract: Polycrystalline alumina bodies have been converted to sapphire by a solid state conversion process in which a localized energy source is used to heat only a portion of the body to a temperature above 1800.degree. C. Using a laser as the energy source resulted in conversion to sapphire in less than an hour. The polycrystalline alumina bodies had a magnesia content below 50 wppm, an average grain size below 100 microns, and a density greater than 3.97 g/cc.

Abstract: Disclosed is an electronic ballast circuit for a high pressure gas discharge lamp with a reduced parts-count starting circuit. The circuit comprises an arrangement for supplying d.c. voltage from a d.c. source, and a main inductor for receiving energy from the d.c. source and supplying the energy to the lamp. The main inductor has a plurality of windings. A first winding of the inductor is coupled to receive energy from the d.c. source. Further included is a current-switching arrangement conductive during periodic first part cycles for transferring energy from the d.c. source to the main inductor, and non-conductive during periodic second part cycles. A first part cycle is followed by a second part cycle in successive periods of switching operation of the current-switching arrangement. The first winding of the main inductor has impressed across it substantially the d.c. source voltage during the first part cycles, and reflects substantially the lamp voltage during the second part cycles.

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 lamp assembly includes improved thermal management properties provided by a thermal shield received about the neck region of a reflector. This reduces the temperature in the seal region of the light source. Additionally, the thermal shield can be incorporated into a modular housing to provide a contained lamp assembly. The module includes cooling fins that effectively reduce the temperature of the module without adversely effecting the light output. Alternatively, the housing is operatively connected to an external, secondary heat sink.

Abstract: A luminaire capable of directing a high percentage of light source output in a downward direction includes a housing base, a light source mounted and electrically coupled to the housing base and a dome-shaped lens member made of light transmissive material disposed in surrounding relation to the light source. The lens member has a first region formed adjacent the housing base on which is disposed a first plurality of prismatic surfaces which both reflect and refract light in the downward direction. A second region is formed on the lens member adjacent the first region and includes a second plurality of prismatic surfaces which refract light output.

Abstract: Disclosed is a ballast circuit for a high pressure gas discharge lamp, including a comparator circuit for producing a feedback error signal representing the difference between a feedback signal and a reference signal. The feedback signal is selectively one of a non-light feedback signal and a light feedback signal, as determined by a switching circuit. A power control circuit adjusts the level of power supplied to the lamp in response to the feedback error signal. A first, non-light feedback circuit supplies a non-light feedback signal to the comparator circuit, based on non-light information of the lamp that is fed back to the non-light feedback circuit. A light feedback circuit operative during a lamp warm-up period supplies a light feedback signal to the comparator circuit based on light intensity information that is fed back to the light feedback circuit.

Abstract: A projection headlamp system is capable of projecting a wide spread controlled pattern of light for accommodating low and high beam illuminations. The projection headlamp system includes a curved reflector and a gas discharge lamp. The curved reflector has first and second optical focal points associated therewith positioned along an optical axis. The first focal point is within and closer to the curved reflector than the second focal point which is spaced from the reflector. The lamp is disposed within the curved reflector at the first focal point thereof and along the optical axis. The lamp is operable for generating light. The curved reflector is operable for receiving a substantial portion of the light generated by the lamp and for directing the light along the optical axis toward the second focal point thereof.

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: Disclosed is an electrodeless, low pressure gas discharge lamp. The lamp includes a vitreous envelope containing a metal vapor and an inert gas. The envelope is shaped with an external chamber for receiving an electrical excitation circuit. The excitation circuit is effective for exciting the metal vapor to emit light with electromagnetic fields that are passed through the vitreous envelope from outside, to inside, the envelope. A circuit supplies electrical power from power mains to the excitation circuit. A transparent, electrically conductive coating is disposed on the inner surface of the vitreous envelope for suppressing electromagnetic interference on the power mains. An electrically conductive coating is disposed on the outer surface of the vitreous envelope; it is capacitively coupled to the inner conductive coating, via a wall of the vitreous envelope, and is maintained at a suitable potential for suppressing electromagnetic interference on the power mains.

Abstract: Incandescent reflector lamps of the R and ER type having a metallic light-reflecting coating inside exhibit a pleasing soft white appearance with substantially diminished glare and filament hot spots when the forward, light-projecting portion of the lamp envelope is coated with a coating comprising a silicone containing untreated titanium dioxide particles of a relatively coarse or large size.

Abstract: A light valve for regulating light through an optical fiber system includes a scattering panel interposed between first and second light guides. A reflecting surface directs the light from the output end of the first light guide toward the input end of the second light guide, thereby eliminating losses associated with known arrangements. Use of a reflecting surface advantageously provides multiple passes through the scattering panel to increase the contrast ratio between on and off states of the system, if desired.

Abstract: A power supply circuit for powering a load with bi-directional current comprises means for supplying d.c. power from an a.c. voltage, a series half-bridge converter, and a boost converter. The series half-bridge converter alternately impresses a d.c. bus voltage from a bus conductor across a load circuit first with one polarity and then with the opposite polarity. The series half-bridge converter includes a first switch interposed between the bus conductor and a bridge-switch end of the load circuit; a second switch interposed between ground and the bridge-switch end of the load circuit; and a switching control circuit for alternately switching on the first and second switches. The boost converter comprises a boost capacitor connected between the bus conductor and ground and whose level of charge determines the bus voltage on the bus conductor; a boost inductor for storing energy from the means for supplying d.c.

Abstract: In accordance with the invention, there is provided a ballast circuit for a gas discharge lamp. The circuit comprises means for providing a d.c. bus voltage on a bus conductor with respect to ground. The circuit includes a resonant load circuit incorporating a gas discharge lamp and including first and second resonant impedances whose values determine the operating frequency of the resonant load circuit. Further included is a converter circuit coupled to the resonant load circuit so as to impress a bidirectional voltage thereacross and thereby induce a bidirectional current in the resonant load circuit. The converter comprises first and second switches serially connected between the bus conductor and ground, and having a common node coupled to a first end of the resonant load circuit and through which the bidirectional load current flows. A current-sensing winding senses at least a portion of the current flowing in the resonant load circuit.

Abstract: A lead ballast circuit with power regulation for a gas discharge lamp includes an input pair of conductors for receiving an a.c. supply voltage, the magnitude of which voltage fluctuates within a known range. Further included is an output pair of conductors for supplying a driving voltage to the lamp. A lead inductor having a magnetic core and a lead capacitance serially connected to the lead inductor between an input, and an output, conductor are included. The inductive impedance of the lead inductor is less than the capacitive impedance of the lead capacitance whereby the aggregate impedance of the serially connected inductor and capacitance is capacitive rather than inductive. The lead ballast circuit also includes a power factor-correcting inductor connected across the input conductor pair, and having a magnetic core that shares a leg in common with the magnetic core of the lead inductor.

Abstract: An incandescent lamp containing a coiled filament within a vitreous envelope wherein the filament is supported at at least one point along its coil length by a refractory metal support wire one end of which is welded to a coil and the other end secured to the envelope wall by a glass bead. The support prevents filament sag during lamp operation and is especially useful with double-ended high intensity tungsten-halogen lamps having an elliptically shaped filament chamber with an infrared reflecting and visible light transmitting optical interference coating on the chamber.

Abstract: A modified lamp includes first and second filaments contained in an envelope to which power is selectively provided individually or conjunctively to obtain three distinct light levels. A contact member in the lamp base is modified to include a planar surface over a major portion of its radial width. Additionally, a lead wire opening that receives one of the lead wires extending from one of the filaments, is spaced from the planar surface to limit the potential for electrical contact with a tang of an associated socket. In one preferred embodiment, the lead wire opening is disposed in a recess that has a maximum circumferential dimension less than the cross-section of the tang to preclude advancement of the tang into the recess. A flat is provided along the outer periphery of the contact member to provide accurate orientation of the contact member during lamp assembly.

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: A sports lighting fixture having a broken glass detection arrangement includes a high intensity light source disposed near the closed end of a reflector member. A cover member made of a light transmissive material is disposed at the open end of the reflector and is effective for filtering UV radiation emitted by the light source. A ballast circuit has in input portion receptive of line power and an output portion effective for conditioning the line power to energize the light source. A conductor strip is disposed on the cover member and is effective such that, when the cover member is intact, an electrical signal can be passed therethrough.

Abstract: An illumination system is disclosed which serves to reduce the divergence of a light beam exiting a small diameter optical fiber from what it was upon entering the optical fiber and is particularly suited for automotive forward lighting applications. The illumination system comprises a spherical reflector, a light source, an optical fiber, a hemispherical lens, and an air gap between the planar surface of the hemispherical lens and the output face of the optical fiber. The spherical reflector allows a light beam from the light source to be introduced into the input face of the optical fiber over a wide angle in order to minimize the diameter of the optical fiber. An air gap exists between the planar surface of the hemispherical lens and the output face of the optical fiber that together with the lens are effective in reducing the angular divergence of the beam from what it was upon entering the input face of the optical fiber.