Achromatized Compressor Prisms
Original Publication Date: 1989-May-01
Included in the Prior Art Database: 2005-Jan-29
Compressor prisms 1 and 2 used in laser delete equipment were achromatized to facilitate accurate prealignment of the He-Ne laser 3 to assure that the working visible Ruby laser 4 struck a target precisely. Due to the wavelength difference of Ruby (6943A) and He-Ne (6328A) alignment laser, the two lasers beams did not track each other at refracting surfaces. Due to refraction at the prisms it was found that the He-Ne beam deviated from the Ruby beam in excess of eight minutes of arc which, over a distance of greater than 21 inches, produced a considerable beam displacement error. The solution was to achromatize the compressor prism 1, and provide an achromatic compensator block 5 so that the He-Ne alignment laser 3 would track parallel to the Ruby cutting laser 4 and no further optical alignments of the Ruby were required.