Eye protection device for welding helmets

A liquid crystal lens assembly for protecting the eyes, comprising

• a. a band pass filter for transmitting visible light of a given wavelength and for blocking transmission of visible light of a different wavelength, and
• b. a liquid crystal device in optical serial relation with said band pass filter,
• said liquid crystal device having variable visible light transmitting conditions as a function of an application of an electric field thereto,
• said liquid crystal device being tuned for operation in the absence of an electric field to transmit some light and to block some light at the wavelength transmitted by said band pass filter,
• said liquid crystal device being responsive to application of a minimal electric field to be tuned to transmit substantially a maximum of light incident thereon, and
• said liquid crystal device being responsive to application of a larger electric field to block transmission of substantially all light incident thereon.

Apparatus for controlling transmission of electromagnetic energy which has a plurality of visible wavelengths and is incident thereon, comprising

• a. band pass filter means for transmitting at least some said electromagnetic energy incident thereon at at least one wavelength and for filtering at least some electromagnetic energy at at least another wavelength, and
• b. a controllable optical device in optical series with said band pass filter means, said controllable optical device being able to assume at least three different operational modes includes,
• i. a first said mode providing substantial transmission of said electromagnetic energy at the wavelength transmitted by said band pass filter means,
• ii. a second said mode providing filtering of a substantial part of said electromagnetic energy transmitted by said band pass filter means, and
• iii. a third said mode providing filtering of at least some of said electromagnetic energy at the wavelength transmitted by said band pass filter means.

A welding helmet comprising a shield means for protecting the face of an individual, an opening in said shield means and apparatus positioned in said opening to provide variable eye protection for the individual, said apparatus being operative for controlling transmission of electromagnetic energy which has a plurality of visible wavelengths and is incident thereon and comprising

• a. band pass filter means for transmitting at least some said electromagnetic energy incident thereon at least one wavelength and for filtering at least some of said electromagnetic energy at least another wavelength, and
• b. a controllable optical device in optical series with said band pass filter means, said controllable optical device being able to assume at least three different operational modes including,
• i. a first said mode providing substantial transmission of such electromagnetic energy at the wavelength transmitted by said band pass filter means,
• ii. a second said mode providing filtering of a substantial part of said electromagnetic energy transmitted by said band pass filter means, and
• iii. a third said mode providing filtering of at least some of said electromagnetic energy at the wavelength transmitted by said band pass filter means.

An eye protection device for protecting the eyes of a welder or the like, comprising a support for supporting a variable protective lens in position to protect said eyes, and a variable protective lens comprising apparatus operative for controlling transmission of electromagnetic energy which has a plurality of visible wavelengths and is incident thereon, comprising

• a. band pass filter means for transmitting at least some said electromagnetic energy incident thereon at least one wavelength and for filtering at least some of said electromagnetic energy at least another wavelength, and
• b. a controllable optical device in optical series with said band pass filter means, said controllable optical device being able to assume at least three different operational modes including,
• i. a first said mode providing substantial transmission of said electromagnetic energy at the wavelength transmitted by said band pass filter means,
• ii. a second said mode providing filtering of a substantial part of said electromagnetic energy transmitted by said band pass filter means, and
• iii. a third said mode providing filtering of at least some of said electromagnetic energy at the wavelength transmitted by said band pass filter means.