Non-invasive blood glucose meter

• US 6,043,492 A
• Filed: 10/27/1997
• Issued: 03/28/2000
• Est. Priority Date: 10/27/1997
• Status: Expired due to Fees

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Liu, Kuo-Kang, Lee, Shih-Ping, Chen, Hsiu-Hsiang, Lin, Ran-Jin
• Primary Examiner(s): Hannaher, Constantine
• Application Number:
  US08/958,338
• Time in Patent Office: 883 Days
• Field of Search: 250/339.12
• US Class Current: 250/339.12
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: G01J 3/26 using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters
• CPC Class Codes: G01N 21/314 with comparison of measurements at specific and non-specific wavelengths dual wavelength spectrometry G01J3/427

Abstract

A non-invasive blood glucose meter includes a near-infrared energy analyzer which includes a light filter assembly of two Fabry-Perot interferometers and a photosensor. The near-infrared energy analyzer detects near-infrared energy absorbed by a human or animal body and generates spectra of such absorption so that the blood glucose content in the body may be analyzed. In order to provide stable energy absorption information of the blood, special designs are provided to stabilize the light source, to calibrate the spectrum and to obviate the noise from the heartbeats of the body. A single crystal silicon elastic power source is used to provide the driving power of the Fabry-Perot interferometer to avoid mechanical hysteresis.

Claims

1. A non-invasive blood glucose meter comprising:

a light source for emitting light onto a human or animal tissue;

a light filter comprising at least two Fabry-Perot interferometers, for receiving light emitted from said light source after passing through said tissue to filter out noise contained in said light;

a light sensor for receiving light filtered by said filter and for transforming said filtered light into an electric format; and

an analyzer for analyzing tissue information contained in said light transformed into said electric format, wherein;

each of said at least two Fabry-Perot interferometers comprises a resonance cavity gap adjustment means for adjusting the gap of a resonance cavity formed inside said at least two Fabry-Perot interferometers respectively and said filter filters said light according to the relation of a matrix of the compound transmittance of said at least two Fabry-Perot interferometers and the electric character of said light sensor,

each of said at least two Fabry-Perot interferometers comprises a moveable silicon substrate, a fixed glass substrate and a resonance cavity formed by said substrates,

said resonance cavity gap adjustment means adjusts said gap of said resonance cavity by supplying to said moveable silicon substrate an elastic force generated by a corrugated structure formed on said silicon substrate and an electrostatic force generated by a controlled electric voltage, and

said moveable silicon substrate comprises an area diffused with highly concentrated boron and a gold film, both functioning as a zero potential electrode and said fixed glass substrate comprises another electrode and said two electrodes function to provide an electrostatic force.

2. The non-invasive blood glucose meter according to claim 1 wherein the wavelength of said light emitted by said light source is within the range of 0.8-1.7 μ

m.

3. The non-invasive blood glucose meter according to claim 1 wherein said light sensor senses light with wavelength within the range of 0.8-1.7 μ

m.

4. The non-invasive blood glucose meter according to claim 1 wherein the material of said light sensor is selected from the group consisting of InGaAs and Germanium.

5. The non-invasive blood glucose meter according to claim 1 wherein the surface of said resonance cavities is coated with a flat gold film with thickness of about 20-35 nm.

6. The non-invasive blood glucose meter according to claim 1 wherein the concentration of boron in said moveable silicon substrate is higher than 10¹⁹ atoms/cm³.

7. The non-invasive blood glucose meter according to claim 1 wherein the thickness of said silicon substrate is within the range of 5-8 μ

m whereby infrared light with a wavelength within the range of 0.8-1.7 μ

m may pass through.

8. The non-invasive blood glucose meter according to claim 1, further comprising a semiconductor laser diode or a light emitting diode to supply calibration light source.

9. The non-invasive blood glucose meter according to claim 1, further comprising a chopper to chop said light into pulses before said light reaches said tissue.

10. The non-invasive blood glucose meter according to claim 1, further comprising a rigid silicon membrane with thickness of about 5-8 μ

m and a flexible corrugated membrane with thickness of about 1-3 μ

m.