Patent ID: 7005624

Claim:
An auto darkening eye protection device comprising: a shutter assembly, the shutter assembly being adjustable to a plurality of shade levels; a light sensing circuit for sensing light from a welding arc and providing an output indicative of the shade level at which the shutter assembly should be operated, the light sensing circuit comprising: a phototransistor operative to receive the light from the welding arc and produce a phototransistor output representative thereof, the phototransistor output from the phototransistor being used to form the output of the light sensing circuit, the phototransistor being configured for surface mount and having an external base connection connected to the base of the phototransistor; a control circuit configured to receive the output from the light sensing circuit and provide a drive signal to the shutter assembly responsive to said output, the drive signal being operative to drive the shutter assembly to one of said plurality of shade levels; and a power source coupled to the light sensing circuit and control circuit for powering same.