Patent ID: 7333841
Filing Date: 2008-02-19
Classification: A61B,G16H

Abstract:
1. A device for calculating a biological component density of a subject, which comprises: a light source generating a light having a NIR (near infrared) spectrum; an incident guide directing said light to a skin of said subject; a reflective guide directing the NIR spectrum reflected back from within said skin; a sensor receiving said NIR spectrum through said reflective guide to provide NIR data thereof; a processing unit which substitutes said NIR data into a predetermined calibrating equation to calculate the biological component density of said subject, characterized in that said device further includes: a skin thickness memory storing a plurality of the calibrating equations which are different from each other and which are each specific to each of a plural groups classified in terms of a skin thickness parameter indicative of a skin thickness with respect to individuals of a species to which said subject belongs; and a means for determining the skin thickness parameter with a non-invasive technique to identify the group of the subject in accordance with the determined skin thickness parameter; said processing unit operating to derive one of said calibrating equations from said skin thickness memory in match with the identified group in order to calculate the biological component density of the subject, wherein said skin thickness memory stores two calibrating equations which are different from each other, one corresponding to a group in which the skin thickness is 1.2 mm or more, and the other corresponding to a group in which the skin thickness is less than 1.2 mm, and wherein said incident guide has a light projecting end adapted to be held in close proximity to said skin, and said reflective guide has a light receiving end adapted to be held in close proximity to said skin, said light receiving end being spaced from said light projecting end by a distance of 2 mm or less across said skin, said incident guide and said reflective guide being made respectively by optical fibers which are integrated into a single probe head having an object end to which said light projecting end and said light receiving end are exposed, said probe including a plurality of different incident guides and a single reflective guide, said different incident guides having individual light projecting ends which are spaced by different distances, respectively from said light receiving end on said object end, a selector being provided to selectively couple one of said different incident guides to said light source so as to direct said light having the NIR spectrum through the selected incident guide, said processing unit further including: a table storing a relation between each one of said groups and each one of said different light incident guides; and a module which analyzes said NIR data statistically based upon the NIR spectrum irradiated through one of said incident paths and received from said skin to determine said skin thickness parameter and to identify the corresponding one of said group, said module operating to select from said table one of said different incident guides as corresponding to the identified group, said module calculating said biological component density based upon said NIR spectrum when the selected incident light guide corresponds with the incident guide which directed the light having the NIR spectrum to the skin to determine the skin thickness parameter, said module enabling said selector to activate the other incident guide and directing the light having the NIR spectrum to said skin once again through the activated incident guide and calculating said biological component density based upon the NIR spectrum received from the skin when the selected incident guide does not correspond with the incident guide which directed the light having the NIR spectrum to the skin to determine the skin thickness parameter.