Radiant energy – Photocells; circuits and apparatus – Photocell controls its own optical systems
Reexamination Certificate
2006-02-28
2006-02-28
Le, Que T. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Photocell controls its own optical systems
C250S2140RC
Reexamination Certificate
active
07005624
ABSTRACT:
An auto darkening eye protection device including a shutter assembly, a light sensing circuit, a control circuit and a power supply source. The shutter assembly is adjustable to a plurality of shade levels. The phototransistor of the light sensing circuit senses light from a welding arc and provides an output of the light sensing circuit indicative of the shade level at which the shutter assembly should be operated. The phototransistor is configured for surface mount and has an external base connection connected to the base of the phototransistor. The control circuit is configured to receive the output from the light sensing circuit and provide a drive signal to the shutter assembly responsive to said output, drives the shutter assembly to one of said plurality of shade levels. The present invention provides reduced power consumption, improved attenuation of low intensity light signals, a sharp rise time from the phototransistor in response to high intensity light, and allows implementation into a smaller sleeker eye protection device.
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Data Sheet; Vishay; “Silicon NPN Phototransistor”; Document No. 81556; May 20, 1999; 5 pages.
Dunlap Codding & Rogers P.C.
Jackson Products, Inc.
Le Que T.
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