Abstract: An electro-optic welding lens assembly for the use in a welder's helmet or protective eyeshield comprises a filter arrangement with at least one liquid crystal light shutter element and a control unit for changing the transmission rate of the filter assembly in response to ambient light conditions. The light sensing element used to control the transmission of light through the filter arrangement is simultaneously an opto-electric transducer, supplying power to the control unit and the light shutter element. Thereby, there is no need for an additional power supply like a battery. If the sensing and transducer element is arranged behind the light shutter element, a self-regulating loop can be realized to continuously vary the transmission rate of the filter arrangement and thereby to keep the viewing illumination through the lens assembly essentially constant.