Abstract: For improving the safety of optical measurements performed with an apparatus comprising a set of light sources and detectors controlled by an electronic unit for measuring an optical or physiological parameter in a scattering medium, in particular human tissue, based on a set of measurement wavelengths, it is suggested that the apparatus features at least one optical contact detector, for example in the form of a photodiode or a light sensitive end facet of an optical fiber or the like, for measuring a detection light quantity resulting from a detection wavelength, and wherein the apparatus issues an alarm signal, in case the measured detection light quantity indicates a low optical coupling efficiency between the apparatus and the medium.

Abstract: A spectrophotometric apparatus for determining optical parameters in a scattering medium based on the measurement of attenuation of light propagating through said medium by diffusion. To eliminate the detrimental effect of light being guided in an intermediate optical layer between a surface of the medium and a contact surface of the apparatus, either a multitude of optical barriers may be formed in the contact surface or the angular range over which light is emitted or received by the apparatus may be limited by appropriate means. With both of these alternative approaches, light propagation in the intermediate layer can be suppressed, leading to increased measurement accuracy. This is particularly beneficial for building an oximeter with improved precision. Further aspects include features for improving the applicability of the apparatus on curved surfaces such as the strongly curved skulls of neonates.

Abstract: A spectrophotometric apparatus for determining optical parameters in a scattering medium based on the measurement of attenuation of light propagating through said medium by diffusion. To eliminate the detrimental effect of light being guided in an intermediate optical layer between a surface of the medium and a contact surface of the apparatus, either a multitude of optical barriers may be formed in the contact surface or the angular range over which light is emitted or received by the apparatus may be limited by appropriate means. With both of these alternative approaches, light propagation in the intermediate layer can be suppressed, leading to increased measurement accuracy. This is particularly beneficial for building an oximeter with improved precision. Further aspects include features for improving the applicability of the apparatus on curved surfaces such as the strongly curved skulls of neonates.