Electro-optic welding helmet lens assembly
First Claim
1. In a welding helmet of the type employing a liquid crystal light shutter as a lens assembly, the combination of first means exposed to light emitted from a welding arc for producing a first electrical signal in response only to visible light from said arc, second means exposed to light emitted from a welding arc for producing a second electrical signal only in response to infrared wave energy from said arc, and circuitry coupled to said first and second means and operable only when both said first and second electrical signals are produced for increasing the opacity of the liquid crystal light shutter.
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Accused Products
Abstract
A protective welding lens assembly for use as the eyepiece of a welding helmet. The lens assembly utilizes a liquid crystal light shutter together with an electrical circuit adapted to change the light shutter from a uniform light-transmitting condition to a uniform, approximately opaque condition of very small light transmission solely in response to light energy emitted by an electric welding arc without the use of any connecting wires. Two light sensing devices are employed, one of which responds to visible light only and the other of which responds to infrared wave energy only. In order to change the light shutter from a light-transmitting to an opaque condition, both the visible and infrared wave energies from the arc must be sensed. This prevents a condition wherein the light shutter will remain opaque, even after the welding arc is extinguished, due to emission of infrared wave energy from a still-hot weld bead.
60 Citations
5 Claims
- 1. In a welding helmet of the type employing a liquid crystal light shutter as a lens assembly, the combination of first means exposed to light emitted from a welding arc for producing a first electrical signal in response only to visible light from said arc, second means exposed to light emitted from a welding arc for producing a second electrical signal only in response to infrared wave energy from said arc, and circuitry coupled to said first and second means and operable only when both said first and second electrical signals are produced for increasing the opacity of the liquid crystal light shutter.
Specification