Patent ID: 8877129

Claim:
A device for optical detection of substances in a liquid or gaseous medium, comprising: a substrate with fluorescent molecules immobilized thereto for detecting substances that are selectively bindable to said fluorescent molecules; said substrate comprising a polymeric foil element comprising an optically transparent plastic material having a thickness of from 10 to 1000 microns; said foil element having at least one light wave coupling structure capable of guiding coupled light waves, the light wave coupling structure including a prism; and said coupling structure being integrally formed with the foil element at a surface of the foil element, said coupling structure being located at an area of the foil element adapted to be brought into contact with the substances to be detected, wherein the coupling structure is a refractive optical element; wherein the prism is provided for simultaneously with the formation of the film in a mold made for coining, rolling or injection molding, and the prism is provided for in one step with the making of the device.