Portable Noninvasive Blood Glucose Measurement Using LED and Tunnel Junction Photodetector
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Solution Overview
Problem
Conventional noninvasive blood glucose measurement devices using light sources like white halogen tungsten lamps or laser diodes are difficult to miniaturize and have high power consumption, making it challenging to create portable and wearable devices that can accurately measure blood glucose levels with high sensitivity, especially in the presence of ambient light and varying skin conditions.
Innovation Solution
A portable apparatus using LEDs as light sources with wavelengths between 400 to 1,000 nm, combined with a tunnel junction light receiving element and a control unit that adjusts light integration time based on environmental and biometric factors, allowing for accurate glucose concentration measurement independent of external influences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If white halogen tungsten lamps or laser diodes are used as light sources for noninvasive blood glucose measurement, then measurement precision is improved, but device size and power consumption increase making miniaturization difficult
Solution Approach 1:
The patent changes the wavelength parameter of the light source from conventional choices (white halogen tungsten lamps or laser diodes) to LED wavelengths between 400-1000 nm. This parameter change enables miniaturization while maintaining measurement precision through optimized wavelength selection that balances glucose absorption characteristics with detector sensitivity.
Solution Approach 2:
The patent employs LEDs which are cheaper, smaller, and more power-efficient compared to conventional light sources. While LEDs have shorter operational lifetimes than some conventional sources, their miniaturized form factor and low power consumption make them ideal for portable wearable devices where size and energy efficiency are critical constraints.
2Measurement precision
If white halogen tungsten lamps or laser diodes are used as light sources for noninvasive blood glucose measurement, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent optimizes the wavelength parameter of the light source to fall within the 400-1000 nm range where LED technology achieves high efficiency. This parameter selection enables low power consumption while maintaining sufficient signal strength for accurate glucose measurement through optimized optical path design.
Solution Approach 2:
The patent employs periodic modulation of the LED light source and synchronized detection to enhance signal-to-noise ratio. By using pulsed LED operation and lock-in detection techniques, the system achieves precise measurements with reduced average power consumption compared to continuous operation of conventional light sources.
3Volume of moving object
If silicon photodiode detector is used to detect light in 400-1100 nm range, then device miniaturization is achieved, but sensitivity to detect trace glucose in blood decreases
Solution Approach 1:
The patent optimizes the wavelength parameter within the 400-1000 nm range to balance detector sensitivity and glucose absorption. By selecting specific wavelength bands and optimizing the LED output characteristics, the system achieves sufficient sensitivity for trace glucose detection while maintaining miniaturization benefits of silicon photodiode technology.
Solution Approach 2:
The patent implements feedback mechanisms where the detected signal is continuously monitored and used to adjust the LED drive current and integration time. This feedback control optimizes the sensitivity of the detection system in real-time, compensating for variations in tissue properties and ambient light conditions while maintaining accurate glucose measurement.
4Measurement precision
If light receiving area of silicon PD is enlarged to detect trace glucose signals, then detection sensitivity is improved, but device miniaturization is compromised
Solution Approach 1:
The patent changes the operational parameters of the photodetector including integration time, gain settings, and wavelength selection to enhance sensitivity without requiring a larger light receiving area. By optimizing these parameters, the system achieves trace glucose detection capability while maintaining a compact detector size suitable for portable devices.
Solution Approach 2:
The patent uses periodic modulation and synchronized detection to enhance signal detection capability. By using pulsed LED operation with optimized pulse width and duty cycle, the system improves signal-to-noise ratio without requiring increased light receiving area, thereby maintaining device miniaturization while achieving high detection sensitivity.
5Adaptability or versatility
If measurement is performed in presence of ambient light and varying skin conditions, then adaptability is improved, but measurement precision decreases
Solution Approach 1:
The patent implements feedback control mechanisms that continuously monitor measurement quality and adjust system parameters in real-time. The control unit analyzes the detected signal characteristics and automatically adjusts LED drive current, integration time, and gain settings to compensate for ambient light variations and skin condition differences, thereby maintaining measurement precision while improving adaptability.
Solution Approach 2:
The patent performs preliminary calibration and baseline measurement procedures before actual glucose measurement. By first characterizing the tissue properties and ambient light conditions, the system establishes compensation parameters that are then applied during measurement, enabling accurate glucose detection despite varying skin conditions and environmental factors.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables reliable, miniaturized, and low-power consumption noninvasive blood glucose monitoring, capable of being worn on the body, with accurate results despite ambient light, temperature, and skin color variations, achieving sufficient sensitivity for measuring glucose levels within the required tolerance.
Implementation Method 1
uses light sources such as light emitting diodes (LEDs), which are easy to miniaturize and lower power consumption... those which range from 800 to 900 nm have the largest depth of penetration... wavelengths which range from 400 to 1,100 nm... absorbed in the covalent bonds of C—H, O—H and others of glucose
Implementation Method 2
measuring a second signal value according to light which is scattered by or transmitted through subject tissue and enters the light measuring unit
Data Source
AI summary
Disclosed is an operating method of a portable apparatus for noninvasively measuring blood glucose levels, and the method comprising (a) measuring a first signal value according to ambient environmental light and temperature by using at least one light receiving elements when an LED which emits light with wavelengths to be absorbed into or scattered by glucose is switched off; (b) measuring a second signal value according to incident light which is scattered by or transmitted through subject tissue and enters the photodetecting unit when the LED is switched on; (c) calculating a glucose concentration measurement of a subject by using the first signal value and the second signal value; and (d) wherein the quantity of light detected by the photodetecting unit is adjusted by feeding the difference between the glucose concentration measurement and a first reference value back to the photodetecting unit.