Confocal chromatic sensor with an actively tilted lens for 3D measurement
Martin Fuerst, Ernst Csencsics, Christian Haider, Georg Schitter
Abstract
Confocal chromatic displacement sensors are versatile and precise sensors for measuring the distance to a single point. In order to obtain a 3D measurement device, this paper presents an integrated scanning sensor design that employs a tilting lens mechanism for manipulating the light path of the sensor. The optical implications of the design are analytically modeled and simulated. An experimental setup is constructed to evaluate the system design and to test its performance on a variety of samples. Results show good agreement with the simulations and modeling; with maximal tip/tilt angles of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>±</mml:mo> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msup> <mml:mn>2.5</mml:mn> <mml:mo>∘</mml:mo> </mml:msup> </mml:mrow> </mml:math> , the setup is capable of measuring a volume of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mn>1.7</mml:mn> <mml:mo>×</mml:mo> <mml:mn>1.7</mml:mn> <mml:mo>×</mml:mo> <mml:mn>1</mml:mn> <mml:mspace width="thickmathspace"/> <mml:msup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">m</mml:mi> <mml:mi mathvariant="normal">m</mml:mi> </mml:mrow> </mml:mrow> <mml:mn>3</mml:mn> </mml:msup> </mml:math> with a lateral resolution of 24.8 µm and an axial resolution of 3 µm.