Abstract: A modified carbon ink for a flash lamp array circuit containing a particulated electrically conductive material such as graphite or metal flakes, metal-coated glass spheres and the like. The increased electrical conductivity obtained in this manner improved flashability and electrostatic flash out protection for the associated flash lamps.

Abstract: A modified conductive ink is provided for a photoflash array having a plurality of high voltage flash lamps connected to a lamp firing circuit pattern deposited on a circuit board with radiation-sensitive switches and fuse elements being connected in said circuit pattern for sequential firing of said flash lamps, said fuse elements being provided by narrowing the width of the circuit pattern at the fuse locations and undergoing thermal decomposition activated with radiation, wherein the improvement comprises a modified carbon ink containing a particulated electrically conductive material such as conductive powdered carbon incorporated therein. Increased electrical conductivity is provided at the fuse locations before thermal decomposition of the fuse elements takes place together with increased residual electrical resistance being provided by the thermally decomposed fused elements.

Abstract: A flash lamp array circuit having radiation-sensitive switches and fuse elements being connected in the conductive carbon ink circuit pattern wherein each of said fuse elements comprises a plurality of spaced apart strips to provide more reliable thermal decomposition and increased electrical conductivity.

Abstract: A flash lamp array having a plurality of high-voltage flash lamps in front of a reflector unit and a circuit board behind the reflector unit and carrying a plurality of circuit runs of relatively high resistance inexpensive material such as powered carbon and including a common or "ground" circuit run connected to a lead-in wire of each lamp. A shield is positioned behind the circuit board and is connected to the common circuit run near a connector tab at an end of the circuit board. This reduces the possibility of accidental flashing of lamps by electrostatic electricity.

Abstract: A flash lamp array having a plurality of high-voltage flash lamps in front of a reflector unit and a circuit board behind the reflector unit and carrying a plurality of circuit runs of relatively high resistance inexpensive material such as powdered carbon and including a common or "ground" circuit run connected to a lead-in wire of each lamp. The common circuit run is made wider than the other circuit runs, and preferably covers a major portion of the circuit board area. This reduces the possibility of accidental flashing of lamps by electrostatic electricity.