A presentation of the company R&D: the company operates in the health-care field, providing systems for the in vitro diagnostic market. The main mission and organization structure of the enterprise R&D are first shown before presenting a real case study: design of a fluorescence detector for immunological diagnostic; from the optical model and electro-mechanical integration to the digital implementation on DSP. A very brief insight on electronics expertise of the R&D is given inside the last part.