Sigma Labs, Inc.
OPTICAL FILTER HAVING DUAL POLARIZATION

Abstract:

An additive manufacturing system comprises a build plane and an energy source configured to direct energy onto a work region of the build plane. An optical detector is configured to receive one or more optical signals from the work region. An optical filter is positioned between the work region and the optical detector, wherein the optical filter includes a first partially transmissive polarized filter having a first polarization axis and a second partially transmissive polarized filter having a second polarization axis. The first polarization axis is rotationally offset from the second polarization axis approximately 90 degrees. The optical filter improves the signal to noise ratio of the optical sensors.