PPG Sensor Layout With Surrounding Photodiodes for Stable Wearables
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wearable devices with PPG modules struggle to obtain stable light signals, leading to inaccurate human body feature measurements, particularly in scenarios with movement and high power consumption.
Innovation Solution
A wearable device with a PPG module featuring a surrounding structure of multiple PDs and LEDs, including a processor that controls light emission based on intensity and frequency, and utilizes different light paths to optimize signal reception and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single PD is used to receive light signals, then the device structure is simple, but the light signal reception is unstable and measurement accuracy deteriorates
Solution Approach 1:
The patent divides the single PD into multiple PDs (at least three) arranged in different spatial positions around the LED. Each PD receives light signals from different directions or paths, and their outputs are combined to improve signal stability and measurement accuracy without requiring a completely new system architecture.
Solution Approach 2:
The patent transitions from a single-point detection (one PD) to multi-dimensional detection by arranging multiple PDs in different spatial positions around the LED. This spatial dimensionality addition allows the system to capture light signals from multiple angles and paths, improving signal reception stability.
2Reliability
If the LED emits light continuously at high intensity, then the light signal reception is maximized, but power consumption increases
Solution Approach 1:
The patent implements periodic light emission by controlling the LED to emit light in pulses rather than continuously. The control module adjusts the emission timing and duration based on the detected motion state, creating a periodic action pattern that reduces average power consumption while maintaining sufficient signal reception stability.
Solution Approach 2:
The patent makes the light emission dynamic by adjusting the LED emission parameters (intensity, timing, duration) based on the real-time motion state detected by the acceleration sensor. When motion is detected, the emission pattern is modified to optimize signal reception while minimizing power consumption during movement.
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
The device achieves accurate human body feature measurements by maximizing light signal reception and minimizing power consumption, extending battery life through a fast charging mechanism.
Implementation Method 1
the PPG module may include a photodiode (Photo diode, PD) and an LED (light emitting diode, LED). When the user monitors a human body feature by using the terminal device including the PPG module, a signal may be transmitted through the LED in the PPG module, a light signal reflected by human tissue through the PD is received
Implementation Method 2
This application relates to the technical field of terminals, and in particular, to a wearable device based on photoplethysmography PPG
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A wearable device based on photoplethysmography PPG and a control method thereof are disclosed, where the wearable device includes a PPG module and a processor (110). The PPG module includes a plurality of light emitting diodes LEDs and a plurality of photodiodes PDs. The plurality of PDs are distributed around the plurality of LEDs in a surrounding structure. Each LED is configured to emit light signals. The LED is a tricolor integrated LED in which red light, green light, and infrared light are combined, and the light signals include a green light signal, a red light signal, and/or an infrared light signal. Each PD is configured to: receive the light signals, and transmit the light signals to the processor (110). The processor (110) is configured to obtain a heart rate feature, a blood oxygen feature, and/or a respiration rate feature based on the light signals received from the plurality of PDs. In this way, the wearable device can obtain a valid PPG signal based on the annular surrounding structure of the plurality of PDs, and then can obtain an accurate human body feature based on the signal.