Optical measurement apparatus and method

摘要

An optical measurement apparatus comprises an optical system (100). The optical system (100) includes a source (102) and a detector (112). The source, when in use, emits a probe beam (116) and the optical system is arranged to direct the probe beam (116) to a location to be measured (114). The detector (112) is arranged to receive a reflected beam (120) from the location to be measured (114). The optical system (100) has a receiving numerical aperture associated therewith and is also arranged so that the probe beam (116) has a probe cone angle corresponding to a probe numerical aperture. The receiving numerical aperture is greater than the probe numerical aperture. The receiving numerical aperture may be provided so as to prevent vignetting of the reflected beam. Alternatively or additionally, the optical system (100) is arranged to apply a magnification ratio between the detector (112) and the location to be measured (114) so as to minimise deviation of the reflected beam from a receiving axis (119) of the optical system (100). The apparatus may be a confocal measurement apparatus for measuring the glucose content of the aqueous humor (e.g. a glucometer to check for diabetes), since the refractive index of the aqueous humor varies in line with glucose content.