The excitation source are green Light Emitting Diodes (LED's). LED's have high stability and are very durable so therefore the lifetime of the light source is virtually infinite.
The excitation filter removes all wavelengths from the excitation light except the green light which illuminates the sample.
The emission filter lets only the red fluorescence light pass.
Both filters are made as hard-coated interference filters which have a high durability and in addition excellent blocking properties for the light to be suppressed.
The red fluorescence light from the sperm cell nuclei in the sample is focused onto the detector (CCD camera). The optical inaging system is made of identical lenses and both lenses are fastened with screws and adhesive.
One of the key features of the NucleoCounter SP-100 is the low magnification of the microscope. The effect of the low magnification is the large area of the sample which is represented in each image.
The section which is blown-up in the figure illustrates approximately the field of view in traditional microscopy methods. The effect of low magnification is clearly visible in the limited spatial representation of each cell, which only expands few pixels.
