Abstract: A high-voltage type photoflash lamp filled with a filamentary combustible material and oxygen and having an ignition structure including a pair of spaced-apart lead-in wires sealed in one end of the glass envelope of the lamp and encapsulated within an interior protruding portion of the envelope glass. The termination of each of the lead-in wires within the envelope is bare of sealing glass and substantially flush with the surrounding glass surface, and a coating of primer material about the inner end of the protruding portion of glass within the envelope covers and bridges the bare terminations of the lead-in wires.

Abstract: A photoflash unit comprising a plurality of high-voltage type flashlamps mounted on a printed circuit board containing circuitry for sequentially igniting the flashlamps in response to successive high-voltage firing pulses applied thereto. One lead-in wire of each of the flashlamps is connected to a common circuit conductor. An electrically conductive reflector unit is positioned between the lamps and the circuit board. The reflector unit is grounded to the common circuit conductor by means of a dried paste of conductive material disposed at the interface between the reflector and common conductor. In this manner, the reflector unit functions as an electrostatic shield for the circuitry.

Abstract: An indicator structure including one or more lengths of perforated tubing arranged in a desired configuration, such as a traffic barricade. The tubing contains one or more flash lamps which produce a light-tunnel effect during operation to provide a high intensity warning or indicating signal in a pre-selected configuration of flash illumination via the tubing perforations.

Abstract: A photoflash unit comprising a linear array of flashlamps mounted on a printed circuit strip disposed within the longitudinal channel of an elongated housing member. A light-transmitting cover panel is attached to the housing member for enclosing the flashlamps. To provide structural rigidity, the cover has rectangular corner posts at each end and a transverse web at the center which engage slots in the housing and are secured by ultrasonic welding. The longitudinal edges are secured by a plurality of cylindrical posts along each side of the cover which fit into matching holes in the housing and have rivet heads formed on the ends as provided by ultrasonic heating and pressure.

Abstract: A tungsten-halogen lamp having a tubular envelope of quartz or high silica glass has a press-seal at one end which is reduced in width by the removal of right-angled sections from opposite lower corners of the press. The lamp further includes a ceramic base having a slot with closed ends for accommodating the reduced width portion of the press-seal.

Abstract: A photoflash unit comprising a linear array of flashlamps mounted on a printed circuit strip disposed within the longitudinal channel of an elongated housing member. A light-transmitting cover panel is attached to the housing member for enclosing the flashlamps. To prevent sympathetic ignition of adjacent lamps, the one-piece cover is molded to have integrally projecting transverse webs which function as light-attenuating partitions between respective pairs of lamps. In addition, the webs bridge the housing channel to provide structural rigidity.

Abstract: For use in a color-corrected photoflash unit, a flashlamp having a clear glass envelope with a transparent protective exterior coating comprising a UV curable photopolymer tinted with a colorant providing a portion of the total color correction capability of the unit.

Abstract: A circuit for starting and operating an arc lamp includes a full wave rectifier having an input connected to a source of alternating current line voltage and a pair of output terminals having a filter capacitor connected thereacross for providing a source of direct current voltage. Connected to one of the direct current terminals is a resonant charging circuit comprising a controlled rectifier switch, an inductor and a capacitor serially connected in a circuit loop. Another inductor, which may comprise the secondary winding of a starting pulse transformer, is connected between the output of the resonant circuit and one of the supply terminals for the arc lamp to provide the dual function of both averaging filter and lamp ballast. The reference terminal of the direct current source is connected to the other arc lamp supply terminal and through a back swing diode to the output of the resonant circuit.

Abstract: A photoflash lamp having a glass envelope with a clear protective exterior coating comprising a photopolymer reinforced with glass fibers. In applying the coating, a long strand of glass fibers is wrapped about the lamp envelope, which is then dipped in a liquid photopolymer, or short lengths of glass fiber are dispersed throughout the liquid photopolymer, either by premixing or application after dipping. The wet-coated lamp is then cure-hardened by a short period of irradiation with a source of ultraviolet light.

Abstract: A switching circuit for energizing a load, such as fluorescent lamp ballasts, in response to a control signal of preselected frequency superimposed on AC power circuits which supply the load. A triac is gated to conduct the AC power to the load by a circuit including an impedance element and a series resonant LC network tuned to the frequency of the control signal. The gate circuit is arranged to block the control signal during all but a small portion of each half cycle of the applied AC power, thereby reducing the consumption of control signal power. Further, a current limiting resistor is connected between the series resonant network and the triac to extend circuit life by protecting the triac from excess current without adversely affecting the signal-blocking function of the gate circuit.

Abstract: A long-duration photoflash lamp comprising a sealed glass bulb containing a gas filling of oxygen and nitrogen, an ignition filament, and a corrugated strip of magnesium foil having a knurled surface for optimizing usable light output.

Abstract: A photoflash unit comprising a plurality of high voltage type flashlamps mounted on a printed circuit board containing circuitry for sequentially igniting the flashlamps. A plurality of electrically conductive reflectors respectively associated with the flashlamps are disposed between the lamps and the circuit board, with each reflector having an aperture in alignment with a corresponding aperture in the circuit board. Connected in series with each but the last lamp of the array is a radiant-energy-activated disconnect switch comprising a strip of electrically conductive heat-shrinkable polymeric material which is attached at both ends to the circuit board so that the midportion of the strip bridges a respective one of the apertures therein. A sheet of electrically insulating material is interposed between the reflectors and circuit board to prevent shorting therebetween. A plurality of deformations, such as dimples, are formed in the insulating sheet for spacing the sheet from the disconnect switch strips.

Abstract: A photoflash lamp in which the combustible material within the lamp envelope comprises a plurality of filaments released from the periphery of a rotating heat-extracting disk in contact with a melt of suitable combustible material, such as hafnium, zirconium or magnesium. Filament configurations are determined to a large degree by the peripheral geometry of the rotating disk. In one embodiment, the filaments have unequal lengths, while in another arrangement, filaments having unequal cross-sections are arranged in a substantially homogeneous mass. In yet another embodiment, each of the filaments has periodic notches along the length thereof.

Abstract: A photoflash lamp array comprising a plurality of high-voltage type flashlamps mounted on a printed circuit board containing circuitry for sequentially igniting the flashlamps in response to successive high-voltage firing pulses applied thereto. Each of the flashlamps has a pair of lead-in wires connected to the circuit board by eyelets which project through to the opposite side of the board, one lead of each lamp being connected via its respective eyelet to a common circuit conductor. Electrostatic protection is provided by a conductive shield of planar configuration disposed parallel to the circuit board and spaced therefrom on the side opposite that on which the lamps are disposed. Selected ones of the common circuit connected eyelets project from the back of the circuit board in a manner which maintains the spacing between the shield and circuit board, to prevent short circuiting of leads, and facilitates electrical connection of the planar shield to the common circuit conductor.

Abstract: A photoflash lamp having a glass envelope with a clear protective exterior coating comprising a photopolymer. In applying the coating, the lamp is dipped in a liquid photopolymer and then cure-hardened by a short period of irradiation with a source of ultraviolet light.

Abstract: A method of applying a protective light-transmitting coating on the exterior surface of the glass envelope of a lamp, the method comprising: holding the lamp with its longitudinal axis disposed horizontally and rotating the lamp about its longitudinal axis; flow-dispensing a liquid coating material of a predetermined viscosity onto the rotating lamp envelope from a dispensing means including a profiled row of needles located above the lamp; and allowing the envelope coating to be cure-hardened, such as by irradiation. The method is particularly useful for applying an optically clear photopolymer coating on the glass envelope of a photoflash lamp in less than one second and then curing the coating by irradiation with a source of ultraviolet light.

Abstract: An intrusion alarm system and method is provided which includes one or more sound pulse transmitters that are triggered upon the opening of an entryway, such as a door or window, to produce a high-intensity sound pulse having a decibel level above a predetermined minimum. For example, each transmitter may comprise a percussive photoflash unit in combination with a pyrotechnic device which responds to the radiant output of the fired photoflash unit to emit the intense sound pulse. A centralized detector responds to the sound pulse above a predetermined threshold level to produce an alarm signal. Preferably, the detector comprises an electroacoustical transducer arrangement which provides the dual functions of both sound pulse detection and generation of an audible alarm.

Abstract: A high-voltage type photoflash lamp having an ignition structure including an improved primer material with enhanced breakdown voltage characteristics for the reliable ignition of filamentary combustible material distributed within the oxygen-filled envelope of the lamp. The primer material comprises a particulate fuel such as zirconium powder, a binding agent such as nitrocellulose, and an additive of relatively coarse inert material which is nonconductive and insoluble in the vehicle used in the applied slurry. A preferred additive consists of glass microbeads having a particle size substantially larger than the zirconium powder used.

Abstract: An isolator circuit for use with a switching circuit for energizing a ballasted load in response to a control signal of preselected frequency superimposed on AC power circuits which supply the load. In the switching circuit, a triac is gated to conduct the AC power to the load by a circuit including an impedance element and a series resonant LC network tuned to the frequency of the control signal. The control signal may be one of a plurality of control signals having different frequencies superimposed on the power circuits. The isolator circuit is connected between the traic and the load and comprises a plurality of series connected parallel resonant LC circuits each tuned to block a respective one of the control signals. A series choke blocks spurious signal voltages.

Abstract: A photoflash unit comprising a plurality of high-voltage type flashlamps mounted on a printed circuit board containing circuitry for sequentially igniting the flashlamps in response to successive high-voltage firing pulses applied thereto. One lead-in wire of each of the flashlamps is connected to a common circuit conductor. An electrically conductive reflector unit is positioned between the lamps and the circuit board. The reflector unit is connected to the common circuit conductor by means of a pliable, electrically conductive adhesive material, whereby the reflector unit functions as an electrical shield for the circuitry.