Tried-and-true technology and techniques together with high-tech products and procedures put a new face on polarization

摘要

Industry-wide, the top quick test to check and see if a lens is polarized or not is the “twist test.” Hold the lens to be checked near another, confirmed polarized lens and rotate one lens until the view through the lenses is dark, indicating a polarized lens. If the view doesn't darken, the lens isn't polarized.With new polarized photochromic technology and brand new variable polarization (clear-to-polarized) lenses, the twist test works as long as the polarization properties are activated first. Testing a non-activated lens won't work.“Activate the lens first, either with outside sunlight or with an appropriate UV light activation demonstrator,” advises John Ligas, director, research and development at Transitions Optical, Inc. “You can then overlay another polarized lens or polarized sheet over the top and rotate 90 degrees. You should see the lens go much darker.”“Since the level of polarization is variable,” he cautions, “this test may not result in total darkness but rather a lens that is darker than without the film.”.