Intensity Control of Triangulation Based PSD Sensor Independent of Object Color Variation

Intensity control of triangulation based position sensitive detector(PSD) sensor is addressed to achieve high linearity against object color variation. The controlled signal is added to the pulse amplitude modulation (PAM) signal of the PSD in order to have the beam intensity of photo diode be regulated constant. The control performance for object color variation is compared with the result when intensity control is not applied. Analytical and experimental results indicate that intensity control provides more accurate and higher linearity than that of PSD sensor without using the intensity control by using analysis and experiments.