Green Sheet Illuminator
Original Publication Date: 1983-Sep-01
Included in the Prior Art Database: 2005-Feb-07
During the inspection of ceramic green sheets it is difficult to observe small (e.g., 0.001") ceramic contamination particles on the surface of the green sheet. The green sheet illuminator disclosed herein provides low angle, collimated light around the four sides of the green sheet. This results in a dark field effect, with a high sparkle indicating the presence of contamination particles. The figure illustrates a cross section of the green sheet illuminator. High intensity neon lamps are mounted on each side of a frame. The lamps project (via a reflector and collimating slit) light around the perimeter of the green sheet at very low angle, to uniformly illuminate the green sheet. The green sheet illuminator can be used in other applications that require a dark field over several lineal inches.