Color mixing in LED illuminating system for endoscopic purposes

Endoscope equipment is used in many applications. One of them is medical diagnostics. The illuminator is an important part of the endoscope, as it enables the performance of the observed object. The quality of light is particularly important if the assessed essential feature is the colour of an object or its distribution on the surface of the object. For this reason, special attention should be paid to the quality of the illuminator in terms of colour rendering, as well as adapting it to the intended diagnostic procedure. The use of light emitting diodes allows shaping flexibly the spectral characteristics which is an innovative solution in case of endoscope equipment. In the paper the idea of the endoscope illuminator construction, based on 13 LEDs, that allows adjusting the correlated colour temperature is presented. The essential part of the paper is the issue of quality of colour mixing. Results of exemplary simulations are presented and compared with the measurement results of performed mixing elements. They are evaluated from the point of view of obtained superficial uniformity of colour mixing on the output of the element.