Eye-shield condensation prevention system for use in a ski goggle, dive mask, medical or testing face shield or the like, that prevents undesirable hot spots on the eye-shield and maintains constant heat, with the ability to compensate for variations in resistance encountered from one eye-shield region to another, and/or one eye-shield to another, comprising a power source, a pulse-width modulator, a microcomputer, a heating element, and a sensing circuit. The microcomputer uses the sensing circuit to sense voltage and determine a value of resistance of the heating element. The microcomputer then uses this value to adjust the duty cycle of the pulse-width modulator, and may employ a two-dimensional table in assisting calculation. Multiple pulse-width modulators may be employed that correspond to a plurality of eye-shield regions and a corresponding plurality of heating elements.
Micro-current sensing auto-adjusting heater system for eye-shield
07.07.2015
Patent
Elektronische Ressource
Englisch
IPC: | G02C SPECTACLES , Brillen / A61F FILTERS IMPLANTABLE INTO BLOOD VESSELS , Filter in Blutgefäße implantierbar / H05B ELECTRIC HEATING , Elektrische Heizung / A42B Hüte , HATS / B63C LAUNCHING, HAULING-OUT, OR DRY-DOCKING OF VESSELS , Zuwasserlassen, Trockenstellen, Docken oder Bergen von Schiffen |
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