Wearable Device Wear State Detection Using Light Pulse Differential
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Solution Overview
Problem
Existing human body wearable devices struggle to accurately detect whether they are worn on a human body or in contact with an object, especially in low-light environments, leading to malfunctions and incorrect wear state detection.
Innovation Solution
A human body wearable device with a light emitting unit and a control unit that generates light and detects the intensity of light incident on a light receiving unit, using a difference value between ON and OFF sections to determine the wear state, and further differentiates between a human body and an object based on heart rate analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the light receiving element measures photo-current magnitude to detect wear state, then the device can detect whether it is worn on a human body, but the detection accuracy deteriorates in low-light environments due to insufficient distinction between ambient light and emitted light
Solution Approach 1:
The light emitting element operates in periodic pulse modes (first pulse mode and second pulse mode) rather than continuous emission. By measuring light intensity at specific time points during the periodic cycle (when first light is emitted vs. when only second light or ambient light is present), the system can distinguish between emitted light and ambient light, thereby maintaining detection accuracy in low-light environments.
2Adaptability or versatility
If the device uses ambient light intensity to determine wear state, then it can operate in various lighting conditions, but it cannot accurately distinguish between being worn on a human body and being in contact with other objects
Solution Approach 1:
The system uses periodic pulse emission with at least two different wavelengths (first light and second light). By comparing light intensity measurements taken during different phases of the periodic cycle, the system can detect characteristics specific to human tissue (such as absorption properties at different wavelengths) versus other objects, enabling accurate discrimination while maintaining adaptability to various lighting conditions.
Solution Approach 2:
The system employs light emitting elements that emit light at different wavelengths (e.g., red and infrared) and measures the differential absorption characteristics at these wavelengths. Human tissue has distinct optical properties at different wavelengths compared to other materials, allowing the system to identify wear state based on local optical property variations rather than overall ambient light levels.
3Measurement precision
If the light emitting element continuously emits light to ensure detection accuracy, then measurement precision improves, but energy consumption increases
Solution Approach 1:
Instead of continuous light emission, the system uses periodic pulse emission where the light emitting element is activated only during specific time intervals (first pulse mode and second pulse mode). This periodic operation maintains sufficient light intensity for accurate measurement during the pulse periods while consuming minimal energy during the off periods, thereby resolving the contradiction between measurement precision and energy consumption.
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 accurate detection of wear state regardless of lighting conditions and prevents malfunctions by distinguishing between wear on a human body and contact with objects, ensuring reliable operation.
Implementation Method 1
The light emitting element 20 generates light of a specific wavelength band depending on a light emitting control signal
Implementation Method 2
The light receiving element 30 receives light incident depending on light generated via the light emitting element 20
Data Source
AI summary
According to an embodiment of the present disclosure, there is provided a human body wearable device including: a light emitting unit for generating light to outside, a light receiving unit for receiving light incident from outside; and a control unit for controlling an operation of the light emitting unit and detecting an intensity of light incident on the light receiving unit depending on the operation of the light emitting unit, and detecting a wearing state of the human body wearable device based on an intensity of detected light, wherein the control unit detects the wearing state using a difference value between an intensity of the light incident on the light receiving unit in an ON section of the light emitting unit and that of the light incident on the light receiving unit in an OFF section of the light emitting unit.