| 摘要 |
An optical sensor is described for providing an output responsive to the position and normality of a test surface with respect to a predetermined plane. A beam of radiant energy is focused by a lens onto the test surface, while being modulated along its optical axis by a first mirror oscillating at one frequency and being modulated transverse to its optical axis by a second mirror at a second frequency. The first harmonic of the frequency of the modulation of the first mirror is then monitored as to phase and amplitude by a single photodetector to provide a measure of the direction and distance of the test surface from the determined plane. The sum or difference harmonic of the radiant energy reflected from the test surface is also monitored as to phase and amplitude by the same photodetector to provide a measurement of the normality of the test surface with respect to the determined plane.
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