Device for characterizing a sample

Abstract

The present invention relates to a device for optical characterisation of a sample and/or of the material(s) of the same having an illumination unit that can be orientated to illuminate with incident light a sample spatial portion into which the sample can be introduced, a detection unit which is orientated or can be orientated to image the sample introduced into the sample spatial portion by receiving light reflected by the sample, and which is configured to detect at least two different, preferably orthogonal, polarization components in the reflected light, and an evaluation unit with which, in the imaging data recorded by the detection unit, those imaged surface elements (reflection elements) of the sample can be identified, and with which the detected different polarization components for these reflection elements can be evaluated for optical characterisation.

What is claimed is: 
     
         1 . A device for characterizing a sample, the device comprising:
 a light source configured to illuminate the sample;   a detector configured to receive light from the light source reflected by the sample, capture a multi-pixel image of the sample from the received reflected light, and detect at least two different polarization components from the received reflected light; and   a processor configured to:   determine a subset of image pixels of the captured image, such that for each image pixel in the subset of image pixels, the reflected light contributing to the image pixel is specularly reflected from the sample, and for each image pixel of the captured image not included in the subset of image pixels, the reflected light contributing to the image pixel is diffusely reflected from the sample, and   for each image pixel in the subset of image pixels, output the detected values of the at least two different polarization components.   
     
     
         2 . The device of  claim 1 , wherein:
 the sample defines a surface normal as being orthogonal to the sample at a center of the sample;   the light source defines an incident axis as extending from a center of the light source to the center of the sample, the incident axis forming an incident angle with the surface normal;   the detector defines an exiting axis as extending from a center of the detector to the center of the sample, the exiting axis forming an exiting angle with the surface normal; and   the processor determines the subset of image pixels, such that for each image pixel in the subset of image pixels, the incident angle equals the exiting angle.   
     
     
         3 . The device of  claim 2 , wherein the incident angle equals a Brewster angle of the sample. 
     
     
         4 . The device of  claim 2 , wherein the light source includes a plurality of individual illumination elements positioned to illuminate the sample with incident light from different directions. 
     
     
         5 . The device of  claim 4 , wherein the plurality of individual illumination elements includes two individual illumination elements. 
     
     
         6 . The device of  claim 4 , wherein the plurality of individual illumination elements includes four individual illumination elements. 
     
     
         7 . The device of  claim 4 , wherein the plurality of individual illumination elements are positioned in a plane that is orthogonal to the incident axis. 
     
     
         8 . The device of  claim 7 , wherein the individual illumination elements are spaced apart equally along a circle, wherein the incident axis intersects the plane at the center of the circle. 
     
     
         9 . The device of  claim 7 , wherein at least one illumination element of the plurality of illumination elements is positioned at an intersection of the incident axis and the plane. 
     
     
         10 . The device of  claim 1 , wherein the light source comprises an individual illumination element. 
     
     
         11 . The device of  claim 1 , wherein the detector includes two cameras and a polarizing beam splitter, the polarizing beam splitter configured to direct light having a first polarization state to one of the two cameras, the polarizing beam splitter configured to direct light having a second polarization state, orthogonal to the first polarization state, to the other of the two cameras. 
     
     
         12 . The device of  claim 1 , wherein two of the at least two different polarization components in the received reflected light are orthogonal to each other. 
     
     
         13 . The device of  claim 1 , wherein:
 the light source includes a laser configured to linearly scan the sample; and   the detector includes a receiver configured to receive laser light reflected by the sample, the detector further including a plurality of polarization-sensitive elements for separating the received laser light according to the different polarization states, the detector further including a plurality of detecting elements configured to receive the separated light in a one-to-one correspondence from the plurality of polarization-sensitive elements.