Optical inspection of gold surfaces
First Claim
1. A method of making an article comprising the step of determining the condition of a gold surface on said article by steps comprising directing illumination from a source toward the inspected gold surface and detecting reflected light therefrom by means of an inspection detector, with said illumination thereby traversing an optical path between said source, said surface, and said detector, characterized in that the reflected light detected by said inspection detector is substantially in the wavelength range of 450 to 575 nanometers, and further characterized in that the amount of reflected light detected in said wavelength range is substantially determined by the degree of scattering of said illumination by said gold surface.
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Abstract
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.
113 Citations
10 Claims
- 1. A method of making an article comprising the step of determining the condition of a gold surface on said article by steps comprising directing illumination from a source toward the inspected gold surface and detecting reflected light therefrom by means of an inspection detector, with said illumination thereby traversing an optical path between said source, said surface, and said detector, characterized in that the reflected light detected by said inspection detector is substantially in the wavelength range of 450 to 575 nanometers, and further characterized in that the amount of reflected light detected in said wavelength range is substantially determined by the degree of scattering of said illumination by said gold surface.
Specification