Patent ID: 7602497

Claim:
A reflectance sensor, comprising: an optical unit, comprising: a light source comprising a lamp; and a fiber-optic system comprising fibers comprising an optical waveguide fiber and a reference waveguide fiber; a sample analysis unit, comprising: a measuring window; and a removable sample analysis cell; and a system control unit, comprising: a detector for recording measured data; and an evaluation device connected thereto; wherein the optical unit is disposed on a first side of the measuring window and the sample analysis cell is disposed on a second side of the measuring window opposite the first side; wherein the analysis cell is pressed against the measuring window to form a gap having a pressure drop between the measuring window and the analysis cell, wherein the gap is traversed by a sample to be measured in the form of a liquid pigment preparation, the sample being sheared by the pressure drop as it traverses the gap, wherein the optical waveguide fiber extends from the light source to the measuring window, and from the measuring window to the detector, to generate a measured reflectance signal; and further wherein the reference waveguide fiber extends directly from the light source to the detector or from the measuring window to the detector to produce a reference signal.