Inspection method and apparatus for partially drilled microvias
View Patent ↗Inspection of partially drilled microvias by fluorescence based optical imaging techniques, selective coaxial illumination and multivariable off-axis illumination and the use of comparative image analysis and the transformation of back reflected radiation by means of an integrated fluorescing plate mounted to the surface of a CCD or EMCCD array.
1. An apparatus for inspecting a laser drilled blind hole, comprising:
an illuminator for illuminating the blind hole with at least UV light,
an objective lens for imaging the blind hole at a CCD, whereas the CCD for converting the images to electric signals,
an indexing filter wheel for making images of fluorescent light emitted from the blind hole at a plurality of wavelengths,
a vision card for grabbing the electrical images as frames, and
a CPU for comparing the image frame to a predetermined good image at each wavelength.
2. An apparatus for inspecting laser drilled blind holes in a printed circuit board, comprising:
an X-Y-Z stage for mounting the printed circuit board,
an illuminator for illuminating the blind hole with at least UV light,
an objective lens for imaging the blind hole at a CCD, whereas the CCD for converting the images to electric signals,
an indexing filter wheel for making images of fluorescent light emitted from the blind hole at a plurality of wavelengths,
a vision card for grabbing the electrically converted images as frames,
a CPU for comparing the image frame to a predetermined good image at each wavelength, and
a motion control for controlling the X-Y-Z stage, the indexing filter wheel with commands from the CPU.