Light curtain safety system

A system to detect obstacles to a power beam using guard beam signals, comprising:

• a plurality of emitters and a plurality of detectors that form a light curtain patterned about the power beam, the plurality of emitters surrounding the power beam having an emitter module including:
• one or more first emitters arranged to emit a first guard beam signal at a first wavelength, the first guard beam signal emitted in proximity to the power beam;
• and
• one or more second emitter arranged to emit a second guard beam signal at a second wavelength, wherein the first wavelength is different than the second wavelength, the second guard beam signal emitted in proximity to the first signal;
• the plurality of detectors surrounding the power beam, the plurality of detectors arranged to respond to the first guard beam signal emitted by the one or more first emitters at the first wavelength and arranged to respond to the second guard beam signal emitted by the one or more second emitters at the second wavelength;
• and
• a controller that directs operations of the plurality of detectors, wherein the controller determines that an unexpected change in a number of detected wavelength signals is indicative of a foreign object near or impeding the power beam, and wherein the controller further generates a responsive signal that causes transmission of the power beam to be stopped in response to the determination of the unexpected change.

A system to detect foreign objects that are approaching the power beam, comprising:

• a plurality of emitters and a plurality of detectors that form a light curtain patterned about the power beam, the plurality of emitters surrounding the power beam having an emitter module including:
• one or more first emitters arranged to modulate a first guard beam signal at a first wavelength, the first guard beam signal emitted in proximity to the power beam;
• and
• one or more second emitter arranged to modulate a second guard beam at a second wavelength, wherein the first wavelength is different than the second wavelength, the second guard beam signal emitted in proximity to the first signal;
• and
• the plurality of detectors surrounding the power beam, the plurality of detectors including:
• one or more first detectors arranged to detect a first guard beam signal emitted by the one or more first emitters at the first wavelength;
• one or more second detectors arranged to detect a second guard beam signal emitted by the one or more second emitters at the second wavelength;
• and
• a controller that directs operations of the one or more first detectors and the one or more second detectors, wherein the controller determines that an unexpected change in intensity of the detected guard beam signals is indicative of a foreign object near or impeding the power beam, and wherein the controller further generates a responsive signal that causes transmission of the power beam to be stopped in response to the determination of the unexpected change.