| 摘要 |
A protective welding lens assembly for use as the eyepiece of a welding helmet in which the lens assembly can be changed from a light-transmitting condition to an essentially opaque condition of very small light transmission, and vice versa, in response to an electrical signal and wherein the electrical signal for changing the light-transmitting characteristics of the lens assembly is controlled by energy emanating from the mouth of the user of the welding helmet. Preferably, the lens assembly comprises a liquid crystal light shutter; however any lens assembly can be used which can be electrically actuated to change its light-transmitting characteristics. A transducer is disposed within the welding helmet so as to be in front of the mouth of the welder when the helmet is positioned over his face. The transducer can comprise either a microphone responsive to sound from the welder's mouth or a pressure transducer responsive to blowing from the welder's mouth. An electrical signal generated by the transducer is then used to control the light-transmitting characteristics of the lens assembly.
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