Optical Sensor Calibration via Switchable Reference Plate
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Solution Overview
Problem
Noninvasive biological information acquisition apparatuses face challenges in maintaining accuracy due to changes in sensor sensitivity over time, affecting the detection of reflected light intensity.
Innovation Solution
An information acquisition apparatus with a photoreceiver, a calibrator with stable reflectance, and a switcher that alternates between reflected light from the object and the calibrator, allowing for calibration and accurate detection of light intensity changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a light source unit and imaging section are used to detect blood information, then noninvasive blood analysis can be performed, but the accuracy of detected light information decreases with time due to component degradation
Solution Approach 1:
The patent applies preliminary action by introducing a calibration plate with known reflectance properties before actual measurements. This calibration plate serves as a reference standard that allows the system to detect and compensate for sensitivity changes in the imaging section and light source unit over time, thereby maintaining detection accuracy throughout the sensor's operational lifespan
Solution Approach 2:
The patent implements feedback through a calibration process where the reflected light from the calibration plate is measured and used to adjust or compensate for changes in sensor sensitivity. By continuously or periodically referencing the known reflectance of the calibration plate, the system can correct for degradation in the light source or imaging section, maintaining reliable detection accuracy over extended periods
2Duration of action of stationary object
If the quantity of light from the light source decreases or imaging section sensitivity lowers, then measurement capability is maintained, but the accuracy of detected light information decreases
Solution Approach 1:
The calibration plate acts as an intermediary with known optical properties. By measuring the reflected light from this intermediate reference object with stable reflectance, the system can indirectly detect changes in light source intensity or sensor sensitivity, and subsequently compensate for these changes to maintain measurement precision over time
3Measurement precision
If a calibrator with stable reflectance is introduced to compensate for sensitivity changes, then detection accuracy is maintained, but device complexity increases
Solution Approach 1:
The patent extracts the calibration function into a separate, independent calibration plate with stable reflectance properties. This separate calibration component can be integrated into the existing measurement apparatus without fundamentally redesigning the core measurement system, thereby adding precision while minimizing increases in overall device complexity
Data Source
AI summary
A component measurement apparatus includes: a sensor module that receives reflected light and outputs a signal corresponding to light intensity of the reflected light; a calibration plate that outputs first reflected light to the sensor module, the first reflected light being used for comparing the light intensity of the reflected light; and a calibration unit that switches the input reflected light to the sensor module between the second reflected light reflected at a measured portion, and the first reflected light.