초록 ▼

An improved method and apparatus for determining noninvasively and in vivo one or more unknown values of a known characteristic, particularly the concentration of an analyte in human tissue. The method includes: (1) irradiating the tissue with infrared energy (400 nm-2400 nm) having at least several

An improved method and apparatus for determining noninvasively and in vivo one or more unknown values of a known characteristic, particularly the concentration of an analyte in human tissue. The method includes: (1) irradiating the tissue with infrared energy (400 nm-2400 nm) having at least several wavelengths in a given range of wavelengths so that there is differential absorption of at least some of the wavelengths by the tissue as a function of the wavelengths and the known characteristic, the differential absorption causeing intensity variations of the wavelengths incident from the tissue; (2) providing a first path through the tissue; (3) optimizing the first path for a first sub-region of the range of wavelengths to maximize the differential absorption by at least some of the wavelengths in the first sub-region; (4) providing a second path through the tissue; and (5) optimizing the second path for a second sub-region of the range, to maximize the differential absorption by at least some of the wavelengths in the second sub-region. In the preferred embodiment a third path through the tissue is provided for, which path is optimized for a third sub-region of the range. With this arrangement, spectral variations which are the result of tissue differences (e.g., melanin and temperature) can be reduced. At least one of the paths represents a partial transmission path through the tissue. This partial transmission path may pass through the nail of a finger once and, preferably, twice. Also included are apparatus for: (1) reducing the arterial pulsations within the tissue; and (2) maximizing the blood content in the tissue.

대표청구항 ▼

[ What I claim is:] [1.]1. A method of determining noninvasively an unknown value of a known characteristic, particularly the concentration of at least one analyte in tissue containing multiple spectral interferences, said method including the steps of:(a) providing at least one source of infrared e

[ What I claim is:] [1.]1. A method of determining noninvasively an unknown value of a known characteristic, particularly the concentration of at least one analyte in tissue containing multiple spectral interferences, said method including the steps of:(a) providing at least one source of infrared energy having multiple wavelengths;(b) using at least one means for introducing said infrared energy into said tissue and at least one means for collecting said infrared energy to provide first and second optical paths of different lengths through said tissue;(c) measuring with at least one detector the intensities of at least some of said multiple wavelengths which have traversed said tissue through said first and second optical paths; and(d) calculating said unknown value by using said measured intensities from said first and said second optical paths, said calculating using said measured intensities from both optical paths to compensate for said spectral interferences in said tissue.