Temperature effects in chromatic confocal distance sensors

We show, both theoretically and experimentally, the effect of changes in temperature on measurements of distance and displacement by a typical commercial chromatic confocal sensor. A temperature change of even 1°C can lead to an error which is larger than the specified absolute accuracy of the sensor. The dominant factor in this effect is the change of the refractive index of the optics with temperature. A correction procedure is described which yields high accuracy (better than 5 μm) over a temperature range from -5 to 55°C.