Abstract: A circuit and method for powering a high intensity discharge lamp, such as a high pressure sodium lamp (HPSL) are disclosed. Feedback control is used to achieve a nearly constant amplitude of lamp current so as to attain nearly constant lamp color in a HPSL, and further accommodates considerable variations in a.c. line voltage. The circuit, which shares some features with the method, includes a circuit to supply a d.c. bus voltage and first and second feedback-controlled circuits. The first feedback controlled circuit regulates the bus voltage in response to a first error signal which is derived as a function of peak lamp current and a set point signal for such peak current. The second feedback controlled circuit regulates lamp power in response to a second error signal which is derived as a function of average bus current and a set point proportional to the difference between regulated bus voltage and lamp power.

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: A UV absorbing soda-lime glass containing specific amounts of cerium oxide and iron oxide permits the use of significantly less CeO.sub.2 than is used in prior art glass. The amount of cerium oxide and iron oxide present is 0.02-0.07 wt. % and 0.02-0.06 wt. %, respectively, with a combined total typically no more than 0.13 wt. %. This glass is useful for fluorescent lamp envelopes in absorbing UVB radiation having a wavelength between 280-320 nm, while being transparent to visible light radiation without effecting the color of the light emitted by the lamp.

Abstract: A single-ended low pressure discharge lamp having an Edison base includes at least one U-shaped fluorescent tube having electrode leads which are connected to a ballast arrangement disposed in a housing base. The housing base has an upper part on which the fluorescent tubes are mounted, a connecting part on which a threaded base is mounted and a supporting part formed between the upper part and the connecting part. Lead-in wires are connected from the ballast arrangement to the threaded base in a manner to facilitate automated assembly of the lamp. A first lead in wire connects to the central portion of the threaded base whereas a second lead-in wire connects to the sleeve portion after first passing through a guided opening formed in the housing base between the supporting part and the connecting part.

Abstract: A projection headlamp system for a vehicle includes a high beam subsystem and a low beam subsystem. Each of the high and low beam subsystems includes a pair of light pattern projecting arrangements, a remote single arc discharge light source, a pair of solid optical coupling devices, and a pair of elongated light distributing conductors coupled at output ends to the pair of light pattern projecting arrangements and coupled at input ends to the pair of solid optical coupling devices. The high and low beam subsystems employ either separate single arc discharge light sources or a common single arc discharge light source.

Abstract: An optical coupling assembly is useful for coupling a source of light, having high brightness and being non-coherent and focussed at a focal plane, to a plurality of optical light conductors. The coupling assembly includes an elongated light transmissive coupling member which has a central longitudinal axis and is disposed between the focal plane of the light source and leading ends of the optical light conductors. The elongated coupling member is any one of a limited number of different polygonal cross-sectional shapes. Also, the coupling member can have either a hollow tubular or a solid configuration. The hollow tubular member is coated with a highly reflective material. In one embodiment, the polygonal cross-sectional shape of the coupling member remains constant along the entire axial length of the coupling member.

Abstract: A compact fluorescent lamp having an electronic ballast circuit arrangement which exhibits improved thermal management characteristics includes an input conditioning circuit which performs rectification and optionally, power factor correction of a standard power line current. The output of the conditioning circuit is coupled to a high frequency switching circuit which includes a pair of power MOSFET switching devices operated alternately between an on and an off condition in response to a control signal presented to the respective gate terminals thereof. The gate control signal is developed by sampling the load current and generating a speed-up pulse which, by being transformer coupled to the gate terminals, functions as the gate control signal.

Abstract: An alkali metal vapor arc discharge lamp which operates on DC and employs an amalgam of mercury and an alkali metal such as sodium, has a cathode to anode pressure ratio no greater than 5 and a cathode end temperature at least 50.degree. C. hotter than the anode end temperature to prevent cataphoretic separation of the mercury and alkali metal in the arc discharge during operation of the lamp. The lamp is designed to have a cataphoretic driving parameter (CDP) value of less than 150. The CDP is defined as the product of the arc current in amperes, times the arc gap length in centimeters, divided by square of the inner diameter of the arc tube in centimeters.

Abstract: To protect against flexure-induced failure of the conductors of an electrical cord terminated by an electrical connector, a strain relief in the form of an exterior collar is integrally formed with the connector in aligned relation with an exit opening in the connector body from which the cord emerges. The collar surrounds the exiting portion of the cord and is configured to provide longitudinally offset fulcrums for establishing longitudinally displaced flex points in the cord conductors depending upon the direction of flexure of the cord beyond the connector.

Abstract: A low voltage DC input ballast circuit for a discharge lamp particularly suitable for a central lighting system includes an input filter stage which feeds into a first boost converter circuit controlled by way of a pulse width modulator device. The first boost converter provides warm-up and steady state run signals to the lamp in a voltage fed manner over a coupling circuit using components which are reduced in size relative to conventional discharge ballast circuits. Control circuitry provides various monitoring functions, an example of which is that, in the event of a low input voltage, the lamp will operate in a dimmed or faded manner rather than maintain lumen output by drawing additional current. A second boost converter circuit is associated with a starter circuit arrangement and operates such that starting pulses can be generated and repeated if necessary in a very rapid manner.

Abstract: Improved collection optics for a lighting system comprised of a light source, reflector and light receptive component include a multi-portion reflector or a non-imaging optical collector having a positive curvature located at an input end to the light receptive component. The collection optics capture additional lumens for transmission through the light guide. The optical arrangement can also collect different colors of light from the source that would otherwise be omitted from transmission through the light receptive component.

Abstract: An electrodeless HID lamp having a quartz arc tube having a gas fill contained therein, is energized to a discharge state upon the introduction of a high frequency RF current in close proximity thereto, also includes a starting aid stem which extends from the arc tube. An outer jacket surrounds the arc tube and a portion of the starting aid stem. The outer jacket is pinch sealed at the end from which the starting aid stem extends. This pinch sealing results in the formation of a sealed space between the outer jacket and the arc tube and further allows that, by the gripping of the starting aid stem at the pinch seal region, the arc tube is supported in a fixed non-contacting position within the outer jacket. A sealant material can be applied around the starting aid stem at the pinch seal region to prevent leakage of the sealed space formed within the outer jacket.

Abstract: A base assembly and method of forming the base assembly for a lamp includes an annular eyelet having an axially outward extending protrusion. The lead wire is fed through the eyelet and folded across the protrusion while a contact member sandwiches the lead wire and confines it during a welding operation. The eyelet, contact, and lead wire are thus fusion bonded to provide a solder-free connection.

Abstract: An arc stabilization arrangement for a discharge lamp having a light transmissive arc tube containing a fill of gas excitable to a discharge state upon introduction thereto of a drive signal having a predetermined frequency associated therewith, includes a modulating arrangement effective for providing a modulating signal which is imposed onto the drive signal. The modulating signal has a frequency associated therewith which approximates the acoustic resonance of the gases within the fill, such modulating signal frequency being less than the frequency of the drive signal. In one embodiment of the invention the modulating arrangement is an amplitude modulating scheme effective such that a modulating amplitude of greater than about 5% of the amplitude of the drive signal is achieved. In yet a further implementation of the present invention, the frequency of the modulating signal is swept about a range of frequencies so that a varying acoustic resonance frequency can be encompassed by the modulating signal.

Abstract: Electric lamps made using nickel-plated, high nickel content iron alloy ferrules wherein the ferrules have been heated above their surface oxidation temperature and then reduced during the lamp-making process have strong bonds between the ferrule and solder using non-corrosive soldering flux, even when using lead-free solder.

Abstract: The invention relates to an electrical lamp base and socket assembly for mechanically holding and supplying power to an electrical lamp, having a vitreous envelope, allowing mainly axial motion for the lamp and avoiding any turning motion over a certain angle during its insertion into and removal from the socket. The lamp base and socket are made of insulating material, and the lamp base has slot on its surface while the socket has mechanical means with spring mechanism and protruding parts engaging the slot of the socket.

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: A lighting system particularly suited for an automotive application in which it is desired to utilize a central light source and couple the light output therefrom to a headlamp assembly having a number of conventional components includes introducing an output end of a light guide to the reflector assembly in place of an incandescent lamp, and disposing a mirror at the output end of the light guide to reflect light onto a conventional parabolic reflector. The mirror is preferably planar and serves to direct the light from the output end of the light guide to the parabolic reflector for collimation thereby and subsequent passage through a conventional lens member.

Abstract: A method and a ballast circuit are disclosed for operating a metal halide lamp particularly suited for horizontal applications that provides signals capable of being varied so as to control the power applied to the metal halide lamp while still providing a uniform arc. The ballast circuit has a filter which passes a selected band of frequencies for the operating signals of the metal halide lamp.

Abstract: Yttrium-containing phosphors can be stabilized for use in an aqueous slurry containing a binder, which slurry can be used for coating fluorescent lamps by treating with ammonium dihydrogen phosphate and ammonium hydrogen difluoride to inactivate free yttrium ions. The resulting aqueous slurry is stable and provides coated fluorescent lamps having uniform coatings that are bright and long lasting.