Optical inspection of gold surfaces

摘要

Gold plated surfaces are inspected by means of reflected light in the wavelength range of 450 to 575 nanometers to give a sensitive indication of surface conditions. This test automates the visual inspection for "brown gold" and is advantageously used in continuous strip gold plating operations. The technique may be used as a quality control check or as a process control to correct non-optimum process parameters that lead to degradation of gold surface conditions. In a preferred embodiment, the reflected light from the surface being inspected is compared with light reflected from a reference surface. Alternately, a separate wavelength band, typically 700 to 800 nanometers, is reflected from the surface being inspected and compared to the reflected light in the 450 to 575 nanometer wavelength band.