Patent ID: 6934967

Claim:
A welding-operation, liquid crystal, protection mask for protecting the eyes of a human operator from an arc light generated during a welding operation, which mask comprises: a liquid crystal protection mask main body that is adapted to be attached to the face of a human operator; a detecting means that is disposed in the vicinity of the liquid crystal protection mask main body and that is capable of detecting an incident arc light generated during the welding operation and thus producing a detection result; a liquid crystal light blocking section that is disposed in a position corresponding to the eyes of a human operator wearing the protection mask with the human face being covered by the protection mask main body and that has a liquid crystal member that is capable of blocking the incident light by instantaneously reducing the light transmittance of the liquid crystal in accordance with the detection result output from the detecting means and by means of a liquid crystal driving power source; and a polarizing member that permits light transmittance therethrough when light is incident on the polarizing member in a direction normal thereto to allow the detecting means to produce a detection result but that blocks the transmittance of light sufficiently to not cause the detecting means to produce a detection result when the light is incident thereon at a certain angle exceeding the normal angle of incidence.