Wearable electronic device and method of a wearable electronic device
By combining a photoplethysmography (PPG) sensor and a pressure sensor, the reliability of the PPG signal is determined by measuring the contact force. This solves the problem of inaccurate contact force measurement in traditional wearable devices and achieves accuracy and precision in physiological characteristic monitoring.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- PIXART IMAGING INC
- Filing Date
- 2025-04-16
- Publication Date
- 2026-07-10
AI Technical Summary
Traditional wearable devices cannot accurately measure the contact force between the user's skin and the device, resulting in a decrease in the quality of photoplethysmography (PPG) data and affecting the accuracy of health monitoring.
The system combines a photoplethysmography (PPG) sensor and a pressure sensor. The reliability of the PPG signal is determined by measuring the contact force, and the microcontroller decides whether to output the signal to ensure its accuracy.
The accuracy of physiological characteristic monitoring has been improved. By appropriately adjusting the tightness of the device, the accuracy and precision of the output physiological characteristic data can be ensured.
Smart Images
Figure CN122350652A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a mechanism of a wearable electronic device, and more particularly to a wearable electronic device and a corresponding method thereof. Background Technology
[0002] Generally speaking, traditional wearable devices often cannot measure the contact force between the user's skin and the device when using gravity, optical, or capacitive sensors. Too little or too much contact force will inevitably reduce the quality of the original photoplethysmography (PPG) data, thus affecting the accuracy of health monitoring functions.
[0003] The original photoplethysmography (PPG) signal is a volumetric pulse wave signal acquired optically. It can be used to detect changes in blood volume within the microvascular bed of tissue. Traditional wearable devices typically acquire this PPG signal by irradiating the skin and measuring changes in light absorption. Summary of the Invention
[0004] Therefore, one of the objectives of this invention is to disclose a wearable electronic device and a corresponding method therein, in order to solve the aforementioned problems.
[0005] According to an embodiment of the present invention, a wearable electronic device is disclosed. The wearable electronic device includes a photoplethysmography (PPG) sensor, a pressure sensor, an integrated circuit, and a microcontroller. The PPG sensor is used to sense the user's physiological characteristics by irradiating the user's skin and measuring changes in the absorption of light reflected from the user's skin to obtain a PPG signal when the user wears the wearable electronic device. The pressure sensor is located near the PPG sensor and is used to measure the contact force between the user's skin and the wearable electronic device when the user wears the device. The integrated circuit is coupled to the PPG sensor and the pressure sensor and is used to determine the corresponding reliability level of the PPG signal based on the measured contact force. The microcontroller is coupled to the integrated circuit and is used to determine whether to output the PPG signal information to the user based on the determined reliability level.
[0006] According to an embodiment of the present invention, a method for using a wearable electronic device is also disclosed. The method includes: providing a photoplethysmography (PPG) sensor to sense the user's physiological characteristics by irradiating the user's skin and measuring changes in the absorption of light reflected from the user's skin to measure a PPG signal when the user wears the wearable electronic device; using a pressure sensor located near the PPG sensor to measure the contact force between the user's skin and the wearable electronic device when the user wears the device; determining a corresponding reliability level for the PPG signal based on the measured contact force; and determining whether to output information about the PPG signal to the user based on the determined reliability level. Attached Figure Description
[0007] Figure 1 This is a block diagram of a wearable electronic device according to an embodiment of the present invention.
[0008] Figure 2 This is a schematic diagram of a wearable electronic device as a smartwatch device according to an embodiment of the present invention.
[0009] Figure 3 This is a schematic diagram comparing the waveforms of PPG signals measured under different contact forces (moderate contact force and large contact force) with the normal waveforms of the corresponding reference PPG signals.
[0010] Figure 4 This is a schematic diagram illustrating the relationship between different blood oxygen saturation levels and different contact force values according to an embodiment of the present invention.
[0011] Figure 5 This is a block diagram of a wearable electronic device according to another embodiment of the present invention.
[0012] The reference numerals in the attached figures are explained as follows:
[0013] 100, 500 wearable electronic devices
[0014] 105A, 105B, 105C, 105D PPG sensors
[0015] 110A, 110B, 110C, 110D pressure sensors
[0016] 115 Integrated Circuits
[0017] 120 microcontroller
[0018] 205 case
[0019] 210 crown
[0020] 215 watch strap Detailed Implementation
[0021] The present invention aims to disclose a wearable electronic device and a corresponding method thereof. This wearable electronic device and method can notify different users to wear the wearable electronic device with varying tightness based on the measured pressure applied by different users, thereby obtaining accurate and precise results of the physiological characteristics of multiple different users and improving the accuracy of physiological characteristic detection.
[0022] Figure 1 This is a block diagram of a wearable electronic device 100 according to an embodiment of the present invention. For example, the wearable electronic device 100 includes multiple photoplethysmography (PPG) sensors, multiple pressure sensors, an integrated circuit 115, and a microcontroller 120, such as four PPG sensors 105A to 105D (but not limited to this number) and four pressure sensors 110A to 110D (but not limited to this number). The number of the multiple PPG sensors (or the multiple pressure sensors) may vary depending on different embodiments and is not a limitation of the present invention. A raw PPG signal is an optically acquired volumetric pulse wave signal that can be used to detect changes in blood volume within a tissue microvascular bed. The wearable electronic device 100 can generate or acquire a PPG signal by irradiating the user's skin and measuring changes in light absorption.
[0023] Each of the plurality of PPG sensors 105A to 105D is used to measure and generate a PPG signal (i.e., a raw PPG signal) by irradiating a user's skin and measuring changes in the light absorption of reflected light when the wearable electronic device 100 is worn, in order to sense the user's physiological characteristics (or physiological features, biomarkers). This light may be emitted by the light-emitting circuitry of the plurality of PPG sensors 105A to 105D. Figure 1 (Not shown) The light is emitted to multiple different locations on the user's skin, and then the multiple PPG sensors 105A to 105D detect the reflected light at these locations to measure and generate the multiple corresponding PPG signals.
[0024] Furthermore, for example, four PPG sensors 105A to 105D can simultaneously measure and generate four PPG signals to the integrated circuit 115. Each pressure sensor 110A to 110D is located near a corresponding PPG sensor 105A to 105D and is used to measure the contact force between the user's skin and the wearable electronic device 100 when the user wears the wearable electronic device 100. For example, the wearable electronic device 100 may have a square or circular shape, and the PPG sensor 105A and pressure sensor 110A may be adjacent to each other and located above the center point of the square or circle. The PPG sensor 105B and pressure sensor 110B may be adjacent to each other and located to the right of the center point of the square or circle. The PPG sensor 105C and pressure sensor 110C may be adjacent to each other and located at the bottom of the center point of the square or circle. The PPG sensor 105D and pressure sensor 110D may be adjacent to each other and located to the left of the center point of the square or circle. Alternatively, in another embodiment, the four PPG sensors 105A to 105D and the four pressure sensors 110A to 110D may be adjacent to each other and located at four different corners of the center point of the device. In other words, a pressure sensor and a corresponding PPG sensor are adjacent to each other to work together to generate the sensed contact pressure value and the waveform of the PPG signal corresponding to the contact pressure value, respectively.
[0025] The integrated circuit 115 is connected to the plurality of PPG sensors 105A to 105D and the plurality of pressure sensors 110A to 110D, respectively, and is used to receive sensed contact forces (e.g., sensed contact force values) transmitted from the plurality of pressure sensors 110A to 110D, receive the plurality of PPG signals transmitted from the plurality of PPG sensors 105A to 105D, and determine the plurality of corresponding reliability levels corresponding to the plurality of PPG signals based on the plurality of sensed contact forces. If a sensed PPG signal corresponds to a high reliability level, the signal is reliable (i.e., the PPG signal is accurate). Conversely, if a measured PPG signal corresponds to a low reliability level, the signal is unreliable (i.e., the PPG signal is inaccurate).
[0026] The microcontroller 120 is connected to the integrated circuit 115 and is used to determine whether to output information for a corresponding PPG signal based on one or more determined reliability levels. When the reliability level of a PPG signal is lower than a reference level (i.e., it is a low reliability level), the microcontroller 120 decides not to output the PPG signal information to the user. Only when the reliability level of a PPG signal is higher than the reference level (i.e., it is a high reliability level) will the microcontroller 120 directly output the PPG signal information to the user. Thus, if a sensed PPG signal is determined to be unreliable, the microcontroller 120 decides not to output the PPG signal and may request or notify the user to remeasure the PPG signal to attempt to obtain a reliable PPG signal. The microcontroller 120 will only output the PPG signal when it is reliable. Therefore, since the output PPG signals are reliable, the PPG signals output by the wearable electronic device 100 to the user will be accurate and precise results. In other words, only reliable PPG signals can be output by the microcontroller 120 and displayed to the user.
[0027] For example (but not limited to), wearable electronic device 100 may be a smartwatch worn on the user's wrist. Figure 2 This is a schematic diagram of a wearable electronic device 100 as a smartwatch device according to an embodiment of the present invention. Figure 2 As shown, the wearable electronic device 100 can be a smartwatch, which includes a case 205, a crown 210, a strap 215, and a plurality of PPG sensors 105A to 105D and a plurality of pressure sensors 110A to 110D located at different positions on the bottom of the case 205. The plurality of PPG sensors 105A to 105D and the plurality of pressure sensors 110A to 110D are respectively used to detect PPG signals and contact force values at different corresponding locations on the user's skin. This embodiment is not a limitation of the present invention.
[0028] Furthermore, in practice, when the contact force applied by the wearable electronic device 100 to the user's skin is moderate, the PPG signal measured by a PPG sensor will be accurate. If the contact force is inappropriate (e.g., too great or too small), the measured PPG signal will be inaccurate. Figure 3 This is a schematic diagram comparing the waveforms of PPG signals measured under different contact forces (moderate and large contact forces) with the normal waveforms of the corresponding reference PPG signals. For example... Figure 3As shown in section (a), when the wearable electronics 100 applies a moderate contact force to the user's skin, the variation between the PPG signal measured by a nearby PPG sensor and a corresponding reference PPG signal will be less than a reference error threshold. Therefore, the integrated circuit 115 can determine that the reliability level of the PPG signal is high, that is, under these conditions, the generated PPG signal is accurate. Conversely, as Figure 3 As shown in section (b), when the wearable electronics 100 applies a large contact force to the user's skin, the variation between the PPG signal measured by a nearby PPG sensor and another corresponding reference PPG signal will exceed the reference error threshold. Therefore, the integrated circuit 115 can determine that the reliability level of the PPG signal is low, that is, in this case, the generated PPG signal is inaccurate.
[0029] Figure 4 This is a schematic diagram illustrating the relationship between different blood oxygen saturation levels and different contact force values according to an embodiment of the present invention. For a normal user in a normal state, a normal person's blood oxygen level (also known as SpO2, blood oxygen saturation) is approximately 95%. Figure 4 As shown, when the applied contact force is within this appropriate pressure range, based on the multiple measured PPG signals generated by the multiple PPG sensors 105A to 105D, the blood oxygen level of a normal person can be correctly estimated to be approximately 95% (or higher), and not incorrectly estimated as a low level below 95%. In other words, under these conditions, the measured PPG signals are accurate. Conversely, when the applied contact force is within a smaller or larger pressure range than the appropriate pressure range, the blood oxygen level of a normal person may be incorrectly estimated as below 95%. In other words, under these conditions, the measured PPG signals may be inaccurate and unreliable.
[0030] In one embodiment, when the measured contact force is outside a suitable pressure range (e.g., a preset pressure range), the integrated circuit 115 determines that the reliability level of the measured PPG signal corresponding to the measured contact force is low (i.e., the PPG signal is unreliable). In this case, the microcontroller 120 then decides not to output the corresponding PPG signal information to the user. The microcontroller 120 can then instruct the user to adjust the tightness of the wearable electronic device 100 and measure and generate a PPG signal again to measure the user's physiological characteristics. For example, if the measured contact force is below the preset pressure range, the microcontroller 120 will instruct the user to tighten the wearable electronic device 100 and measure the PPG signal again to obtain the user's physiological characteristics. When the measured contact force is above the preset pressure range, the microcontroller 120 will instruct the user to loosen the wearable electronic device 100 and measure at least one PPG signal again to obtain an accurate PPG signal measurement result.
[0031] Furthermore, in one embodiment, multiple pressure sensors 110A to 110D are located adjacent to multiple PPG sensors 105A to 105D, and are used to measure multiple contact force values and output these contact force values to the microcontroller 120 via an integrated circuit 115. The integrated circuit 115 is used to generate multiple corresponding reliability levels for the measured multiple contact force values. Therefore, when the wearable electronics 100 is worn by a user, the microcontroller 120 can sense and determine the user's operating behavior based on the measured multiple contact force values, and then decide whether to notify the user to change their operating behavior.
[0032] For example, based on multiple measured contact forces and their corresponding reliability levels, the microcontroller 120 can determine and sense specific user actions on the wearable electronic device 100. For instance, when the PPG signals generated by the two PPG sensors located at the right corners of the wearable electronic device 100 have a high reliability level while the PPG signals generated by the two PPG sensors located at the left corners have a low reliability level, the microcontroller 120 can determine that the user's action may cause the wearable electronic device 100 to tilt to the left. Conversely, if the reliability level of the PPG signal from the right PPG sensor is low while the reliability level of the PPG signal from the left PPG sensor is high, the microcontroller 120 can determine that the user's action may cause the wearable electronic device 100 to tilt to the right. It should be noted that based on different combinations of measured contact forces and their possible reliability levels, the microcontroller 120 can accurately sense and determine the user's actions.
[0033] In one embodiment, the preset pressure range can be obtained from a cloud server via an Internet connection. For example, a default pressure range can be transmitted from a host device (e.g., a mobile device, smartphone, etc.) to the wearable electronic device 100 via a wireless connection between the host device and the wearable electronic device 100. The host device then obtains the default pressure range from a cloud server (e.g., a calculator device) via the Internet connection. In other words, in an initial preset setting, the actual numerical range of the preset pressure range can be set by the cloud server for one or more wearable electronic devices 100 of one or more different users. In other words, the numerical range of the preset pressure range does not need to be stored and recorded in a storage circuit of the wearable electronic device 100, and can also be modified by the cloud server according to different situations.
[0034] In one embodiment, the wearable electronic device 100 can independently determine and set the preset pressure range. That is, after setting, a first preset pressure range for one wearable electronic device 100 will differ from a second preset pressure range for another. For example, the wearable electronic device 100 includes a training mode in which each PPG sensor 105A to 105D can measure physiological characteristics multiple times to obtain multiple PPG signals, and each pressure sensor 110A to 110D can correspondingly measure the applied contact force multiple times to obtain multiple contact force values. In this training mode, the wearable electronic device 100 has not yet determined the default pressure range, and the integrated circuit 115 does not generate a reliability level for the PPG signals, but directly transmits the PPG signals and contact force values to the microcontroller 120. The microcontroller 120 calculates multiple differences (or variations) between multiple PPG signals and a reference PPG signal (as a standard and accurate PPG signal), compares these differences with a reference error threshold to obtain multiple first differences less than the reference error threshold, and uses first contact force values corresponding to these first differences (less than the reference error threshold) to determine the preset pressure range. For example, an acceptable error (or tolerance) in PPG measurement might be 1%, which can be used as the reference error threshold. Only when the multiple first differences of the multiple PPG signals are less than the reference error threshold (e.g., 1%) will the microcontroller 120 consider the corresponding multiple first contact force values as moderate pressure values, allowing the microcontroller 120 to use these moderate pressure values to form the preset pressure range, which is a moderate pressure range formed by the largest and smallest moderate pressure values among the aforementioned moderate pressure values. In this way, in the normal mode of the wearable electronic device 100, the integrated circuit 115 can use the determined preset pressure range to determine the reliability level corresponding to the contact force measured in the normal mode.
[0035] Furthermore, in another embodiment, in this training mode, the microcontroller 120 can determine a suitable pressure range as the preset pressure range based on the detected multiple blood oxygen saturations. For example, the microcontroller 120 can calculate multiple blood oxygen levels corresponding to multiple PPG signals respectively, and compare the multiple blood oxygen levels with a reference blood oxygen saturation level to obtain multiple abnormal blood oxygen levels (i.e., values lower than the reference blood oxygen saturation level), thereby determining an abnormal blood oxygen range covering the multiple abnormal blood oxygen levels. For example, the standard blood oxygen level for a generally healthy person is between 95% and 100%. The reference blood oxygen saturation level can be set to 95% (i.e., the lowest value in the 95% to 100% range) and serve as a minimum threshold for a normal blood oxygen level. The microcontroller 120 can compare each calculated blood oxygen level with the reference blood oxygen saturation level (e.g., 95%) to determine and obtain multiple abnormal blood oxygen levels less than 95%, thereby forming and obtaining the abnormal blood oxygen range covering the multiple abnormal blood oxygen levels. For example, for one user, if the maximum of multiple abnormal blood oxygen levels they calculate might be 94%, then the abnormal blood oxygen range can be determined to be between 0% and 94%. For another user, if the maximum abnormal blood oxygen level is close to 95%, then the abnormal blood oxygen range could be between 0% and 95%.
[0036] After obtaining the abnormal blood oxygen range, the microcontroller 120 can determine a normal blood oxygen range by excluding the abnormal range, and then determine the preset pressure range by using a contact force range corresponding to the normal blood oxygen range. For example, if the user's abnormal blood oxygen range is between 0% and 94%, the normal blood oxygen range obtained by excluding the abnormal range is 94% to 100%. In another example, if the user's abnormal blood oxygen range is between 0% and 95%, the normal blood oxygen range obtained by excluding the abnormal range is 95% to 100%. Finally, after obtaining the normal blood oxygen range, the microcontroller 120 may acquire all possible contact force values corresponding to all blood oxygen values within the normal blood oxygen range to determine a contact force range that can cover these contact force values as the preset pressure range (i.e., a calculated appropriate pressure range).
[0037] Furthermore, in one embodiment, the aforementioned reference blood oxygen saturation level can be fine-tuned according to different altitude conditions. For example, in a high-altitude environment, a normal blood oxygen saturation level may also be in the range of 90% to 95%, so the reference blood oxygen saturation level can be adjusted down to 90% (but not limited to this). Similarly, the aforementioned normal blood oxygen range can also be fine-tuned according to different situations.
[0038] In another embodiment, the default pressure range can be initially set to the same range for different users, and then the microcontroller 120 can adjust it to different ranges according to the different users. For example, for a first user, the microcontroller 120 can adjust the preset pressure range to a first pressure range, and for a second user, the default pressure range can be adjusted to a second pressure range, wherein the two are different pressure ranges.
[0039] Furthermore, in another embodiment, the microcontroller 120 in this training mode can simultaneously determine the preset pressure range based on the detected blood oxygen saturation level and multiple differences (or variations) calculated between multiple PPG signals and the reference PPG signal. Its operation is similar to the aforementioned steps and will not be detailed here. Additionally, in one embodiment, the number of pressure sensors can be set to one. Figure 5 This is a block diagram of a wearable electronic device 500 according to another embodiment of the present invention. Figure 5 As shown, the wearable electronic device 500 may be a smart ring device (but is not limited to) and includes a single PPG sensor 105A, a corresponding single pressure sensor 110A, the integrated circuit 115, and the microcontroller 120.
[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A wearable electronic device, characterized in that, include: A photoplethysmography (PPG) sensor is used to sense the user's physiological characteristics by irradiating the user's skin and measuring the changes in the absorption of light reflected from the user's skin when the user wears the wearable electronic device, thereby measuring the PPG signal. A pressure sensor, located near the photoplethysmography sensor, is used to measure the contact force between the user's skin and the wearable electronic device when the user wears the device. An integrated circuit, coupled to the photoplethysmography sensor and the pressure sensor, is used to determine the corresponding reliability level of the photoplethysmography signal based on the measured contact force. as well as A microcontroller, coupled to the integrated circuit, is used to determine whether to output the photoplethysmography (PPG) signal information to the user based on the determined reliability level.
2. The wearable electronic device as described in claim 1, characterized in that, When the measured contact force is outside the preset pressure range, the reliability level is determined to be low, and the microcontroller decides not to output the photoplethysmography signal to the user. The preset pressure range is a medium pressure range.
3. The wearable electronic device as described in claim 2, characterized in that, The microcontroller is used to notify the user to adjust the tightness of the wearable electronic device, and to measure the user's physiological characteristics by measuring the photoplethysmography signal again.
4. The wearable electronic device as described in claim 3, characterized in that, When the measured contact force is below the preset pressure range, the microcontroller is used to notify the user to tighten the wearable electronic device and to measure the user's physiological characteristics by measuring the photoplethysmography signal again; and when the measured contact force is above the preset pressure range, the microcontroller is used to notify the user to relax the wearable electronic device and to measure the user's physiological characteristics by measuring the photoplethysmography signal again.
5. The wearable electronic device as described in claim 2, characterized in that, The default pressure range is transmitted from the host device to the wearable electronic device via a wireless connection between the host device and the wearable electronic device, and the host device obtains the default pressure range from a cloud server via an internet connection.
6. The wearable electronic device as claimed in claim 2, characterized in that, The wearable electronic device includes a training mode in which the photoplethysmography sensor measures the photoplethysmography signal multiple times to obtain multiple photoplethysmography signals, and the pressure sensor measures the contact force multiple times accordingly to obtain multiple contact forces. Furthermore, the microcontroller calculates multiple differences between the plurality of photoplethysmography (PPG) signals and the reference PPG signal, compares the plurality of differences with a reference error threshold to obtain a plurality of first differences that are less than the reference error threshold, and determines the preset pressure range by using a plurality of first pressure values corresponding to the plurality of first differences that are less than the reference error threshold.
7. The wearable electronic device as claimed in claim 2, characterized in that, The wearable electronic device includes a training mode in which the photoplethysmography sensor measures the photoplethysmography signal multiple times to obtain multiple photoplethysmography signals, and the pressure sensor measures the contact force multiple times accordingly to obtain multiple contact forces. Furthermore, the microcontroller calculates multiple blood oxygen levels corresponding to the multiple photoplethysmography signals, compares the multiple blood oxygen levels with a reference blood oxygen saturation level to obtain multiple abnormal blood oxygen levels below the reference blood oxygen saturation level, thereby obtaining an abnormal blood oxygen range covering the multiple abnormal blood oxygen levels, and determines a normal blood oxygen range by excluding the abnormal blood oxygen range, and then determines the preset pressure range by using a pressure range corresponding to the determined normal blood oxygen range.
8. The wearable electronic device as claimed in claim 2, characterized in that, The microcontroller is used to adjust the preset pressure range to become a first pressure range for a first user and a second pressure range for a second user, and the first pressure range is different from the second pressure range.
9. The wearable electronic device as claimed in claim 1, characterized in that, The wearable electronic device includes multiple photoplethysmography (PPG) sensors and multiple pressure sensors located near the PPG sensors; the multiple pressure sensors are used to measure multiple contact forces and output the multiple contact forces to the microcontroller; the microcontroller is used to sense the user's operating behavior based on the measured multiple contact forces, and then decide whether to notify the user to change the user's operating behavior based on the sensed user's operating behavior.
10. The wearable electronic device as claimed in claim 1, characterized in that, The wearable electronic device is intended to be worn on the user's wrist.
11. A method for using a wearable electronic device, characterized in that, include: Provide a photoplethysmography (PPG) sensor to sense the user's physiological characteristics by irradiating the user's skin and measuring the changes in the absorption of light reflected from the user's skin when the user wears the wearable electronic device. A pressure sensor located near the photoplethysmography sensor is used to measure the contact force between the user's skin and the wearable electronics when the user wears the wearable electronics. The reliability level of the photoplethysmography signal is determined based on the measured contact force. as well as The decision on whether to output the photoplethysmography (PPG) signal to the user is based on the determined reliability level.
12. The method as described in claim 11, characterized in that, The method further includes: When the measured contact force is outside the preset pressure range, the reliability level is determined to be low, and the information of the photoplethysmography signal is not output to the user; the preset pressure range is a medium pressure range.
13. The method as described in claim 12, characterized in that, The method further includes: The user is notified to adjust the tightness of the wearable electronic device, and the user's physiological characteristics are measured by measuring the photoplethysmography signal again.
14. The method as described in claim 13, characterized in that, The method further includes: When the measured contact force is below the preset pressure range, the user is notified to tighten the wearable electronic device, and the user's physiological characteristics are measured again by measuring the photoplethysmography signal; and When the measured contact force exceeds the preset pressure range, the user is notified to relax the wearable electronic device, and the user's physiological characteristics are measured by measuring the photoplethysmography signal again.
15. The method as described in claim 12, characterized in that, The default pressure range is transmitted from the host device to the wearable electronic device via a wireless connection between the host device and the wearable electronic device, and the host device obtains the default pressure range from a cloud server via an internet connection.
16. The method as described in claim 12, characterized in that, The wearable electronic device includes a training mode in which the photoplethysmography (PPG) sensor measures the PPG signal multiple times to obtain multiple PPG signals, and the pressure sensor correspondingly measures the contact force multiple times to obtain multiple contact forces. The method further includes: Calculate the multiple differences between the multiple photoplethysmography (PPG) signals and the reference PPG signal respectively; The multiple differences are compared with a reference error threshold to obtain multiple first differences that are less than the reference error threshold; and The preset pressure range is determined by using a plurality of first pressure values corresponding to a plurality of first differences that are less than the reference error threshold.
17. The method as described in claim 12, characterized in that, The wearable electronic device includes a training mode in which the photoplethysmography (PPG) sensor measures the PPG signal multiple times to obtain multiple PPG signals, and the pressure sensor correspondingly measures the contact force multiple times to obtain multiple contact forces. The method further includes: Calculate the corresponding blood oxygen levels for each of the multiple photoplethysmography (PPG) signals; The multiple blood oxygen levels are compared with a reference blood oxygen saturation level to obtain multiple abnormal blood oxygen levels that are lower than the reference blood oxygen saturation level, thereby obtaining an abnormal blood oxygen range that covers the multiple abnormal blood oxygen levels. as well as The normal blood oxygen range is determined by excluding the abnormal blood oxygen range, and then the preset pressure range is determined by using the pressure range corresponding to the determined normal blood oxygen range.
18. The method as described in claim 12, characterized in that, The method further includes: The preset pressure range is adjusted to become a first pressure range for the first user and a second pressure range for the second user, and the first pressure range is different from the second pressure range.
19. The method as described in claim 11, characterized in that, The wearable electronic device includes multiple photoplethysmography (PPG) sensors and multiple pressure sensors located near the PPG sensors, and the method further includes: Multiple pressure sensors are used to measure multiple contact forces, and these multiple contact forces are output to a microcontroller; and When the user wears the wearable electronic device, the system senses the user's actions based on the measured multiple contact forces, and then determines whether to notify the user to change their actions based on the sensed user actions.
20. The method as described in claim 11, characterized in that, The wearable electronic device is intended to be worn on the user's wrist.