| 摘要 |
A photoflash unit comprising a plurality of 2n flashlamps attached to a printed circuit board and disposed in a linear array with the longitudinal axes of respective lamps aligned in parallel. Circuit patterns on the circuit board include a plurality of n selective terminal means, each associated with a respective pair of the lamps and connected to one lead-in wire of each of the lamps of the associated pair, and a common terminal associated with all of the 2n lamps but directly connected to the other lead-in wire of one lamp of each pair. Groups of circuit pattern extensions are located behind alternate lamps of the array, the first group comprising two spaced apart segments and the remaining groups each comprising three spaced apart segments. Each group of segments is covered with a mass of radiation sensitive switch material to thereby provide respective solid state switches between bridged segment gaps which are activated upon receiving radiant energy emitted by an adjacent lamp. The circuit pattern arrangement provides a pair of respective normally open switches coupled between the common terminal and a lead-in wire of the other lamp of each pair of lamps, except for the last, one switch positioned for activation by the prior lamp in sequence and the other switch positioned for activation by the next lamp in sequence. In this manner, the second lamp of the first n-1 pairs of lamps can be switched by either of two parallel radiation switches, thereby providing redundant switching in the event that the first lamp in any of the first n-1 pairs of lamps is defective. |
