Patent ID: 6882411

Claim:
A method of inspecting optical devices comprising: (a) illuminating the optical device and a surrounding background with light, wherein said light comprises a first wavelength band and a second wavelength band, wherein said first wavelength band and said second wavelength band are different wavelengths, and wherein said first wavelength band has a first intensity and said second wavelength band has a second intensity; (b) transmitting said light through said optical device wherein the majority of said first wavelength band is absorbed by said optical device and the majority of the second wavelength band is transmitted through said optical device, and capturing said optical device transmitted light on a photo-sensitive pixel array; (c) transmitting said light through said surrounding background wherein the majority of said first wavelength band and said second wavelength band are transmitted, and capturing said background transmitted light on a photo-sensitive array; (d) reading pixels generated from step (b) and step (c) and comparing the gray scale values of said reading, wherein the difference between the grayscale values of the pixels generated from said background transmitted light and from said optical device transmitted light is of sufficient value to distinguish between holes in said optical device and bubbles in said surrounding background.