Detector system for detecting the occurrence of welding using detector feedback
AssigneeOSD Envizion Company
InventorsJohn D. Fergason, Jeffrey K. Fergason
Life of this patent
Estimating the term…
Abstract
A power supply circuit for a liquid crystal welding lens or shutter develops a relatively low voltage AC signal for driving or powering the liquid crystal shutter to the clear state and two relatively higher or larger magnitude AC electrical signals for initially driving the shutter to the dark state and then for maintaining the shutter in the dark state; a variable frequency circuit for varying the frequency of the driving signal to the shutter to minimize power usage in the dark state and to avoid flicker in the clear state; and power saving and battery level indicator features are included.
Claims15
A detector system for detecting the occurrence of welding, comprising detector means for receiving a light input and producing an output representative thereof;
- feedback means coupled with respect to said detector means for tending to maintain substantially constant such output of said detector means as the intensity of said light input varies, said feedback means having a relatively slow time constant,
- comparator means for producing a comparison output, said comparator means including means for comparing such output with respect to a threshold signal and for producing said comparison output representative of the result of such comparison, and
- tracking means for causing the value of such threshold signal to track the value of such output relatively slowly, whereby relatively rapid transitions in such output of at least a prescribed magnitude will cause one comparison output and relatively slow variations in such output will result in a different comparison output.
A shutter system for controlling transmission of at least one of visible, infrared, and ultraviolet light, comprising
- a variable transmission device for selectively transmitting light as a function of a drive signal thereto,
- output circuit means for delivering such drive signal to said variable transmission device, and
- a detector system for detecting the occurrence of light and controlling operation of said output circuit means, said detector system comprising detector means for receiving a light input and producing an output representative thereof,
- feedback means coupled with respect to said detector means for tending to maintain substantially constant such output of said detector means as the intensity of incident light varies, said feedback means having a relatively slow time constant,
- comparator means for producing a comparison output, said comparator means including
- means for comparing such output with respect to another signal and for producing a comparison output representative of the result of such comparison, and
- tracking means for causing the value of such another signal to track the value of such output relatively slowly, whereby relatively rapid transitions in such output of at least a prescribed magnitude will cause one comparison output and relatively slow variations in such output will result in a different comparison output.
An eye protection system comprising:
- detector means for receiving a light input and producing an output representative thereof;
- comparator means for producing a comparison output, said comparator means including means for comparing said output with respect to a threshold signal and for producing said comparison output representative of the result of such comparison;
- threshold signal developing means for developing said threshold signal, the magnitude of said threshold signal tending to follow the magnitude of said output;
- and
- light shutter means for controlling transmission of incident light as a function of said comparison output.
Dependencies are inferred from the claim text.