Abstract: An optical-fiber breakage detection system continuously monitors the integrity of a laser-guiding fiber, whether the laser itself is on or off. If an interruption is detected, the system may cut off, lock out, or reduce laser power, as appropriate. An optical element such as a beamsplitter is used to introduce an optical test signal into one end of the fiber so that the signal is carried by the fiber to the other end where the test signal is detected and employed to perform a desired function. In the preferred embodiment, the test signal is modulated and encoded to minimize false shut-downs. The source of the optical test signal is preferably disposed at the first location and carried by a second fiber to the remote location, enabling the test signal to be compared directly to the test signal as detected.

Abstract: A transparent overlay is back lit using an electroluminescent panel which is energized, either continuously or intermittently, by a battery operated electronic DC-AC inverter circuit with flasher circuit. The entire assembly including battery is housed in a lightweight plastic case, which has a fastener on the back for fastening to the wearer.

Abstract: Temperature control mechanism takes the form of discrete electronic circuit or programmed digital computer for accurately regulating the temperature of a hydrate forming solution in a metal halogen battery during charge. The electronic circuit and/or digital computer senses the actual solution temperature, by measuring the temperature of coolant circuit in thermal communication therewith. The actual temperature is compared with a set point temperature based on curve fitting algorithm for approximating the hydrate formation temperature which changes during charge. For sufficiently large differences between actual and set point temperatures, an electrical impulse is applied to servo driven mixing value to selectively increase or decrease flow of chilled coolant to the coolant circuit.