Optical device components
Inventors
Assignees
University of Missouri System • St Louis Medical Devices Inc
Publication Number
US-7809418-B2
Publication Date
2010-10-05
Expiration Date
2028-10-03
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Abstract
Embodiments of the invention relate to an apparatus including a light source to generate a plurality of light beams with each of the plurality of light beams having a different wavelength range. The apparatus also includes a light funnel to direct the plurality of light beams to the target area, an aperture to direct the plurality of light beams emitting from the target area to a lens, the lens configured to collect the light beams emitting from the target area. Further, the apparatus includes a detector including a plurality of light-sensing devices each configured to detect a light beam and configured to generate an output signal indicative of an intensity of light detected and a processor for determining the blood characteristic as a function of each generated output signal.
Core Innovation
The invention relates to an apparatus designed to enhance non-invasive optical measurement of blood characteristics such as glucose level. The apparatus includes a light source that generates a plurality of light beams, each beam having a distinct wavelength range. A key component is a frusto-conical light funnel, which gathers the light beams through a larger entrance and directs them to a target area, such as a fingertip, via a smaller exit, thus increasing the intensity of light at the target.
An aperture collects the light beams after they pass through the target area, and a lens, such as an aspheric lens, further collects and focuses the light onto a detector array. The detector contains multiple light-sensing devices, each configured to detect specific wavelengths, often via associated interference filters. A processor receives output signals from these devices and determines a blood characteristic as a function of the detected light intensity.
This approach addresses the limitations of previous optical devices, notably the low light power reaching detectors and high noise levels due to signal attenuation in small, battery-powered, non-invasive blood monitoring devices. The combination of the light funnel, improved collection optics, wavelength-selective filtering, and signal processing results in enhanced signal-to-noise ratio and measurement accuracy for determining blood characteristics such as glucose concentration.
Claims Coverage
The patent contains two independent claims, each introducing major inventive features for optical blood characteristic determination.
Optical apparatus with frusto-conical light funnel and multiple wavelength light sources
An optical apparatus comprising: - A light source that generates multiple light beams, each having a different wavelength range. - A frusto-conical light funnel that collects the multiple light beams through a larger entrance opening and directs them to a target area through a smaller exit opening. - An aperture to direct the light beams emitted from the target area. - A lens configured to collect light beams from the aperture. - A detector with multiple light-sensing devices, each configured to detect a light beam and output a signal indicative of light intensity. - A processor for determining a blood characteristic as a function of each generated output signal.
Apparatus with light funnel, light source, collection optics, detectors, and filters for blood characteristic determination
An apparatus comprising: - A light source to generate a plurality of light beams, each with a different wavelength range. - A frusto-conical light funnel with an entrance opening (first diameter) and a smaller exit opening (second diameter). - An aperture for directing light beams from the target area. - A lens to collect the light beams from the aperture. - One or more detectors configured to generate output signals based on detected light intensity. - One or more filters between the lens and the detector(s). - A processor to determine a blood characteristic based on each generated output signal.
The inventive features center on the integration of a frusto-conical light funnel, precise wavelength selection, optimized light collection and detection, and signal processing to improve non-invasive blood characterization.
Stated Advantages
The light funnel significantly increases the total light power received by the target area, thus enhancing the signal-to-noise ratio compared to conventional designs.
Using an aspheric lens as a collector increases the total light power received by each detector by a factor of 3 to 4 over traditional configurations.
Combining a light illumination funnel with improved collection optics can increase the light power detected by about 20 to about 40 times compared to known systems.
Employing a transmission grating for wavelength separation reduces wasted light and increases the light power delivered to each photodiode by a factor of 10 to 20 over conventional structures.
The combined use of light funnel, aspheric lens, and transmission grating can increase detected light power by about 100 to 200 times compared to prior art configurations, improving measurement accuracy.
Documented Applications
Non-invasive measurement of blood characteristics such as glucose, cholesterol, and hemoglobin levels in human or animal subjects by optical spectroscopy.
Self-monitoring of blood glucose (SMBG) concentration by diabetics in a home environment without the need for drawing blood.
Use in optical instrumentation such as optical detectors, microscopes, and spectrometers for measurement and analysis applications.
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