Abstract: A welding helmet and lens therefor includes a shield and a lens including a two identical optical components, each including a polarizer, a further polarizer (analyzer) optically between said optical components and effectively shared as an output device from one optical component and an input device for the other optical component, the transmissive axes of respective polarizers of said optical components being operatively oriented relative to one another to improve extinction of light incident on said lens at prescribed angles. The lens may be used in other optical systems.

Abstract: A frame assembly for a light shutter including a frame structure for enclosing an electro-optic shutter assembly, the frame structure having a front surface which can be positioned opposite a cover lens, and a switch for controlling an operation mode of the electro-optic shutter assembly, the switch being mounted on the front surface whereby pressure applied to the cover lens activates the switch. The frame assembly can be inserted and used in a welding helmet or other protective eyewear having a standard sized lens aperture.

Abstract: A driving circuit for a liquid crystal shutter or for other devices that reduces the power drain on the portable power supply and has the characteristic of fast response time. Accurate voltage regulation also is provided by referencing an accurate reference voltage supplied by a diode.

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.

Abstract: A sensor circuit for detecting light hazards or bright light sources that will cause discomfort. The sensor and sensor electronics which provide a wide sensitivity range which is fully automatically adjustable, and which has the ability to detect point sources of light. The sensor further has the ability to distinguish low power stable light generated from a small welding arc from bright ambient light or even direct sunlight.

Abstract: Light transmission control device includes band pass filter for transmitting light of a wavelength or group of wavelengths and partially blocking transmission of light of a different wavelength or group of wavelengths, and variable optical filter for controllably transmitting light of a wavelength or group of wavelengths, the band pass filter and variable optical filter being cooperative to provide at least three light transmitting modes, including maximum transmission, minimum transmission, and a third mode less transmissive than the maximum, the device being operative to minimum transmissive mode upon being driven by a maximum energy input, the device also being operative to maximum transmissive mode upon being driven by a lesser energy input, and such third transmission mode occurring in response to no power or a failure of power or adequate power for energizing the device to the maximum or minimum transmissive mode.