IES20020553A2 - A luminescence-based sensor assembly - Google Patents

Abstract

The present invention relates to a luminescence based sensor assembly of the type comprising a superstrate, a substrate mounting on an emitting spot, an array of spots or a layer transmitting luminescence into the substrate and excitation source and a detector for measuring some of the light omitted into and transmitted out of the substrate and addresses deficiencies in the prior art with coupling the luminescence to the detector. In particular the invention provides a luminescence sensor configuration for use in a medium having a first refractive index, the sensor configuration comprising a source of direct illumination, a substrate having an upper and lower surface and being of a second refractive index, a material capable of luminescence, a detector arrangement provided below the lower surface of the substrate and adapted to detect light emitted through that lower surface, light emitted through that lower surface, and wherein, in use, the medium and the substrate meet along the upper surface of the substrate which defines the boundary between the fires and second refractive indices, the material capable of luminescence is excited by the source of direct illumination, thereby luminescence and the detector arrangement is adapted to discriminate between luminescent light emitted from a region within a predetermined distance of the upper surface and light emitted from any other regions, the discrimination being effected by selective detection of light emitted from the luminescent material at angles greater than the critical angle of the medium/substrate interface. <Figure 16>