Multiwavelength Readhead for Use in the Determination of Analytes in Body Fluids

摘要

A readhead (10) for use in the determination of the concentration of an analyte in a sample comprises a read area (30) for receiving the sample, a light source (12) including a plurality light emitting elements for outputting light at a plurality of wavelengths such as a multiwavelength surface mount light emitting diode (SMD LED), a light guide (16) having an input end and an output end (18), a lens (22) for receiving light from the output end (18) of the light guide and for illuminating the sample with a substantially collimated beam of light (26), and a detector (34) for detecting light (36) from the sample in response to illuminating the sample. The input end of the light guide (16) being optically coupled to the light source (12) for receiving light output by the plurality of light emitting elements. The input end of the light guide (16) has a center that is offset from the center of at least one of the plurality of light elements. The light guide (16) guides a substantial portion of the light received from the light source to the output end of the light guide. An acrylic light guide (16) having a square cross-section creates an even illumination distribution for each wavelength at the output end (18) of the light guide (16) even though LED dies of an SMD LED are offset from the center of the light guide (16).