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: 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: 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: 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: The invention relates to an electrode-inlead assembly for electrical lamps which comprises a lead-in-wire connected to a foil made of refractory metal and the foil is connected to a shank made of refractory metal and supporting the electrode.The object of the invention is, that the shank is made of two parallel rods which are joined by their one end portions, and their opposite end portions are welded to the foil, so that the foil is sandwiched between the rods.

Abstract: This headlamp comprises a reflector and a discharge lamp comprising an inner envelope having a longitudinal axis coinciding with the optical axis of the reflector. The inner envelope includes a bulbous portion, a front leg extending along the optical axis from the bulbous portion toward the front of the headlamp, and a back leg extending along the optical axis from the bulbous portion toward the reflector. The discharge lamp further comprises a tubular shroud comprising a first hollow portion surrounding the front leg of the inner envelope, a second hollow portion surrounding the back leg of the inner envelope, and a bulbous portion between the two hollow portions. The bulbous portion of the shroud has a central longitudinal axis, and this central axis is upwardly offset by a small distance (e.g., at least about 0.5 mm) from the longitudinal axis of the inner envelope on which the discharge is located.

Abstract: A high pressure discharge lamp with a thermally improved anode, as well as a method of making such a lamp, are disclosed. The lamp includes a refractory arc tube with a hermetically sealed arc chamber, a fill in the arc chamber for facilitating light generation, and an anode and a cathode extending into the hermetically sealed arc chamber and being spaced apart from each other. The anode comprises a shank of refractory metal, a cylindrically shaped refractory metal sleeve on a portion of the shank, and an end proximally facing the cathode. The anode end comprises a substantially solid mass of refractory metal, and is integrally joined to both the shank and the metal sleeve to facilitate heat flow from the anode end to the shank and sleeve. The anode end preferably is generally shaped as a hemisphere facing the cathode. The refractory metal sleeve is preferably one or more layers of a helically wound refractory metal wire having an outer diameter more than twice a diameter of the shank.

Abstract: A liquid crystal display (LCD) is provided with a source of backlighting which augments reflected incident light to provide increased contrast. A liquid crystal cell which does not contain dye, but becomes clear when a field is applied, is sandwiched in back of a liquid crystal cell with a dye and electrically connected so that when the front liquid crystal cell is turned ON to make selected portions of it transparent, the back liquid crystal cell is OFF so that corresponding portions of it are highly reflecting. No voltage is allowed to be applied across nonselected portions of the front liquid crystal and a voltage is applied across corresponding nonselected portions of the back liquid crystal making the nonselected portions of the back liquid crystal clear, producing a display of high contrast. Sandwiched to the rear of the back liquid crystal cell is a clear plastic wedge which is edge lighted.

Abstract: Asymmetric discharge electrode means are provided for a metal halide lamp enabling improved operation at acoustic frequencies. A xenon-metal halide lamp employing such improved discharge electrode means is disclosed together with a reflector lamp unit employing such lamp construction for its light source.

Abstract: This headlamp comprises a reflector and a discharge lamp comprising an inner envelope having a longitudinal axis coinciding with the optical axis of the reflector. The inner envelope includes a bulbous portion, a front leg extending along the optical axis from the bulbous portion toward the front of the headlamp, and a back leg extending along the optical axis from the bulbous portion toward the reflector. The discharge lamp further comprises a tubular shroud comprising a first hollow portion surrounding the front leg of the inner envelope, a second hollow portion surrounding the back leg of the inner envelope, and a bulbous portion between the two hollow portions. The front leg is provided with a large-diameter integral enlargement (referred to herein as a "large-diameter maria"), and the shroud is joined to the front leg by a maria seal located at the outer periphery of this maria.

Abstract: A high brightness discharge light source includes an arctube having an arc chamber formed therein and in which is disposed a fill of gas energizable to a discharge condition. At least two electrodes extend into the arc chamber and are separated by an arc gap of between 2 and 3.5 mm. The dose of mercury disposed in the arc chamber and various arc tube dimensions are selected so as to achieve a balance between three constraints including operating voltage thereby defining lamp efficacy, convective stability and structural integrity of the discharge lamp. A balance between arc gap, arc chamber diameter, wall thickness and the mercury density of the lamp yield a discharge lamp which achieves a light output on the order of 50,000 lumens per square centimeter.

Abstract: Heat sink means are provided for a metal halide lamp to enable more light output during lamp start-up. A xenon-metal halide lamp employing the heat sink means is disclosed along an with automotive headlamp having this lamp for its light source.

Abstract: Miniature high pressure arc lamps containing a substantial pressure of xenon, in addition to metal halide and mercury, can provide instant light at turn-on and are suitable for automotive headlamps. The xenon aggravates convection which causes arc-bowing and overheating of the envelope above the arc. By operating the lamps on unidirectional current upon which a frequency-modulated high frequency ripple has been imposed, acoustic resonance is used to straighten out the arc. The use of unidirectional current permits a reduction in cost and size of the ballast control circuits operated from auto storage battery. Frequency modulation of the ripple broadens the band allowing acoustic straightening of the arc. Additional control of the arc plus reduction of cataphoresis may be achieved through a horizontal magnetic field at the arc, transverse to current flow.

Abstract: Fused quartz containing both titanium dioxide and cerium oxide as UV absorbing dopants has been found to be particularly effective for lamp envelopes for high temperature lamps such as halogen-incandescent lamps and metal halide arc discharge lamps which emit both UV and visible light radiation. The codoped quartz transmits visible radiation and absorbs a substantial portion of the emitted UV radiation. The UV absorption is far superior at temperatures above 500.degree. C. and the codoped quartz does not react with the fill within.

Abstract: Miniature high pressure arc lamps containing a substantial pressure of xenon, in addition to metal halide and mercury, can provide instant light at turn-on and are suitable for automotive headlamps. The high pressure of xenon aggravates convection which causes arc bowing and overheating of the envelope above the arc. By operating the lamp at high frequency within selected bands, acoustic modes are excited in the fill which straighten the arc and make the envelope more isothermal. Frequency modulation of the input can be used to broaden the band selected for acoustic operation and relax the tolerance on arc tube and circuit parameters needed for a match. Acoustic operation may also be used to effect physical displacement of the arc for beam switching.

Abstract: Anode and cathode means are provided for a metal halide lamp which cooperate in providing more rapid light output during lamp start-up. A xenon-metal halide lamp employing the improved discharge electrode means is disclosed along with an automotive headlamp having this lamp for its light source.

Abstract: A method and a ballast circuit are disclosed for operating a xenon-metal halide lamp particularly suited for automotive applications with a direct curernt (DC) levels having selectable amount of ripple imposed thereon. The ripple provides for acoustically straightening the arc between the electrodes of the xenon-metal halide lamp. The DC acoustic operation has the capability of utilizing cataphoresis effect so as to provide a less distracting forward beam illumination for a vehicle.

Abstract: An arc discharge headlamp system employs a single continuously operating arc discharge source to provide both high and low beam patterns. The continuously operating arc discharge increases lamp life and eliminates the problem in arc light source headlamp systems of momentary dimming when switching to high beam operation due to mercury condensing within source. The headlamp has an arc light source mounted horizontally within a reflector. Light from an arc light source is reflected by the reflector through a lens to form a low beam pattern. A mirror within the reflector is positioned to form a virtual image of the light source and which is directed towards a second lens concentric with the first lens to form a high beam pattern when combined with the low beam pattern. Switching between the high beam and low beam patterns is accomplished in a variety of ways.

Abstract: An apparatus to compensate for refraction of radiation passing through a curved wall of an article is provided. The apparatus of a preferred embodiment is particularly advantageous for use in arc tube discharge diagnostics. The apparatus of the preferred embodiment includes means for pre-refracting radiation on a predetermined path by an amount equal and inverse to refraction which occurs when radiation passes through a first wall of the arc tube such that, when the radiation passes through the first wall of the arc tube and into the cavity thereof, the radiation passes through the cavity approximately on the predetermined path; means for releasably holding the article such that the radiation passes through the cavity thereof; and means for post-refracting radiation emerging from a point of the arc tube opposite its point of entry by an amount equal and inverse to refraction which occurs when radiation emerges from the arc tube.