Application Notes for Glass Measurements
Measurements To Thick Glass Targets
Philtec sensors are retro-reflective type probes: they emit light which reflects off targets and then returns to the probe tips for signal processing. With opaque targets, light reflects from the front surface. With glass targets light is reflected from the front surface and from the back surface. When the glass is thin, these
two refl ected signals are of approximately equal strength. With thick glass, the amplitude of the back side reflection is diminished significantly, so the resulting signal is mainly comprised of the front side reflection.