Fibre optic coupling plate for checking fluorescence in a sample

A fibre optic coupling plate 24 has a sample viewing face 14 for receiving light from a sample 20, an output window 18 for conveying light from the sample to a detector 22 and an additional surface. A primary light path 16 conveys light from the viewing face 14 to the output window 18 and a second separate light path 10 conveys excitation radiation from the additional window to the viewing surface 14. The coupling plate 24 is further used for checking fluorescence in a sample 20 and is used in an imaging apparatus which further includes a CCD camera and a sample holder adjacent to the viewing surface 14.