Abstract: Reflective coating means are provided to replace the conventional reflector cavities surrounding each photoflash lamp of a multilamp photoflash array. A reflective adhesive coating for this purpose can be applied to each photoflash lamp around a portion of the lamp circumference to reflect the light outwardly in a desired direction. A reflective adhesive coating can also be applied to the circuit board member used with a photoflash lamp array to provide sequential firing of flash lamps as an alternate means to provide the desired light reflection and without need for individual lamp processing in achieving this result. The coating material comprises light reflective particulate solids bonded to the substrate with an adhesive binder.

Abstract: A photoflash lamp unit is described having a plurality of flash lamps fired individually and in sequence to include a plurality of switching devices each connected in the electrical circuit so as to interrupt the circuit path to a lamp that is flashed in response to the radiation emitted therefrom but still provide a circuit path to other unflashed lamps in the electrical circuit. In this manner, the desired firing sequence can be carried out although a particular flash lamp in the electrical circuit fails to fire because of defects other than a before-flash shorted condition and a more reliable switching arrangement is thereby provided.

Abstract: Reflecting coating means are provided to replace the conventional reflector cavities surrounding each photoflash lamp of a multilamp photoflash array. A reflective adhesive coating for this purpose can be applied to each photoflash lamp around a portion of the lamp circumference to reflect the light outwardly in a desired direction. A reflective adhesive coating can also be applied to the circuit board member used with a photoflash lamp array to provide sequential firing of flash lamps as an alternate means to provide the desired light reflection and without need for individual lamp processing in achieving this result. The coating material comprises light reflective particulate solids bonded to the substrate with an adhesive binder.

Abstract: An electrically insulative adhesive coating for a circuit board used with a photoflash lamp array to provide sequential firing of the flash lamps. The circuit board includes the lamp firing circuitry along with switching elements connected in said circuitry and the insulative coating prevents electrical shorting of the circuitry. In a preferred embodiment, the coating material may be an organic polymer and may be provided with openings to permit radiation transfer from the flashing lamps to the underlying switches which are radiation-responsive.

Abstract: Fuse elements are used with a circuit board to provide more reliable sequential firing in a flash lamp array. The circuit board includes the lamp firing circuitry along with radiation switches connected in said circuitry and the fuse elements cooperate with said radiation switches in the circuit operation. Fuse elements are deposited on the circuit pattern adjacent to the flash lamps for actuation by radiation being emitted therefrom and the activated fuse elements interrupt the circuit path by thermal action. In a preferred embodiment, the circuit board is constructed from an organic polymer and the fuse elements are deposited at circuit locations wherein the underlying substrate has a thickness less than the substrate thickness elsewhere to produce holes in the circuit board by melting or thermal decomposition.

Abstract: Flash lamp array sequencing circuits in which the lamps are provided with heat-sensitive switch material on the outside surface of the bulbs and extending between lead-in wires. The switch material initially has a relatively high impedance, and changes to a relatively low impedance between the lead-in wires when heated by the lamp when it is flashed. A coating of lacquer or plastic is provided over the bulb and switch material.