Eye protection device for welding helmets

  • US 5,208,688 A
  • Filed: 02/08/1991
  • Issued: 05/04/1993
  • Est. Priority Date: 02/08/1991
  • Status: Expired due to Term
First Claim
Patent Images

1. A light transmission control device, comprisinga. band pass filter means for transmitting visible light of a prescribed wavelength and for blocking transmission of visible light of a different prescribed wavelength, andb. variable optical filter means for controllably transmitting light of a visible wavelength, andc. wherein said band pass filter and variable optical filter are cooperatively related to provide at least three different light transmitting conditions, including a maximum transmission, a minimum transmission, and a third transmission.

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