Blood component measurement apparatus
First Claim
1. A blood component measurement apparatus for measuring a blood component in the arterial blood of a subject body comprising:
- an illuminating device for illuminating said subject body with predetermined light periodically at first timings;
a light intensity detector for detecting light intensity measurement values of light transmitted through said subject body;
a dark level detector for detecting dark level measurement values periodically at second timings without illumination from said illuminating device;
a pulse wave detector for extracting a pulse wave component from said light intensity measurement values, and thereby detecting pulse wave measurement values; and
a blood component measurer for measuring the blood component of said arterial blood on the basis of said light intensity measurement values, said dark level measurement values, and said pulse wave measurement values;
wherein each time interval between said first timings and said second timings is an integer multiple of the period corresponding to a line frequency.
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Accused Products
Abstract
In a pulse oximeter (blood component measurement apparatus), a subject body is irradiated periodically with red light and infrared light. Then, carried out sequentially in a time sharing manner are the measurement of the transmitted light intensity through the subject body, the measurement of the pulse wave component of the transmitted light intensity, and the measurement of the dark level in the state that the subject body is not irradiated with the light. On the basis of these measurement values, oxygen saturation of the arterial blood is measured. In the present embodiments, each measurement is carried out with a time interval equal to the period corresponding to the line frequency. In this approach, periodic noise of the line frequency or other noise are eliminated in dark level correction. This permits precise measurement of the blood component.
240 Citations
14 Claims
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1. A blood component measurement apparatus for measuring a blood component in the arterial blood of a subject body comprising:
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an illuminating device for illuminating said subject body with predetermined light periodically at first timings;
a light intensity detector for detecting light intensity measurement values of light transmitted through said subject body;
a dark level detector for detecting dark level measurement values periodically at second timings without illumination from said illuminating device;
a pulse wave detector for extracting a pulse wave component from said light intensity measurement values, and thereby detecting pulse wave measurement values; and
a blood component measurer for measuring the blood component of said arterial blood on the basis of said light intensity measurement values, said dark level measurement values, and said pulse wave measurement values;
wherein each time interval between said first timings and said second timings is an integer multiple of the period corresponding to a line frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
a second generator for correcting said pulse wave measurement values on the basis of said dark level measurement values, and thereby generating corrected pulse wave measurement values;
an interpolator for interpolating one of said corrected light intensity measurement values and one of said corrected pulse wave measurement values detected by illuminating with said two kinds of light having different wavelengths at timings different from each other, using said corrected measurement values before and after the timing of illumination; and
a calculator for calculating a simulated value of said corrected light intensity measurement value and a simulated value of said corrected pulse wave measurement value which are simulated as if measured at the same timing when said two kinds of light having different wavelengths illuminate simultaneously, on the basis of the interpolation carried out in said interpolator.
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12. The blood component measurement apparatus according to claim 9, wherein said light intensity detector detects said light intensity measurement values amplified by using a first gain, and when said illuminating device does not illuminate said subject body, said dark level detector detects said dark level measurement values amplified by using a second gain equal to said first gain.
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13. The blood component measurement apparatus according to claim 9, wherein said pulse wave detector detects said pulse wave measurement values amplified by using a first gain, and when said illuminating device does not illuminate said subject body, said dark level detector detects said dark level measurement values amplified by using a second gain equal to said first gain.
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14. A method of measuring a blood component in the arterial blood of a subject body, comprising the steps of:
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illuminating said subject body with predetermined light periodically at first timings by an illuminating device;
detecting light intensity measurement values of light transmitted through said subject body;
extracting a pulse wave component from said light intensity measurement values, and thereby detecting pulse wave measurement values;
detecting dark level measurement values periodically at second timings without illumination from said illuminating device; and
measuring the blood component of said arterial blood on the basis of said light intensity measurement values, said dark level measurement values, and said pulse wave measurement values;
wherein each time interval between said first timings and said second timings is an integer multiple of the period corresponding to a line frequency.
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Specification