Abstract

A light probe method and apparatus is provided for an infrared body chemistry measurement instrument. The light probe includes an illumination ring of a light-conducting material, having facets on an exterior circumferential surface, and an inner circumferential surface at about a forty-five degree angle, infrared light emitting devices positioned at each facet, a coaxially located optical detector, a shielding ring coaxially located between the optical detector and the illumination ring, and a cover having a central opening which exposes the optical detector, the shielding ring, and the illumination ring, wherein a length dimension of the light probe is less than a diameter dimension. The method includes radially illuminating an illumination ring with infrared light, redirecting the infrared light to an axial direction perpendicular to the radially inward direction, conducting the infrared light through the illumination ring and into a body part under test, and receiving reflected and scattered light in an optical detector concentric with the illumination ring.