Patent ID: 8042958

Claim:
An automatic darkening protective shield, comprising: an automatic darkening filter (ADF) helmet; a switchable filter mounted in the ADF helmet, the switchable filter capable of changing from a light state to a dark state in response to a control signal; a switchable filter control unit capable of applying the control signal to the switchable filter in response to detected levels of incident light when the filter control unit is in an ON state but not when the filter control unit is in an OFF state; and a power management control unit comprising a sensor that senses movement of the ADF helmet, the power management unit transmitting an activation signal to the switchable filter control unit if the sensed movement satisfies a threshold condition, causing the switchable filter control unit to enter into an ON state, but if the threshold condition is not satisfied, the power management control unit causes the switchable filter control unit to remain in or enter the OFF state, wherein the threshold condition corresponds to a minimum level of sensed movement that may result from a user activity, and wherein a user is not required to control power to the automatic darkening protective shield prior to use.