Intelligent ring system and light interference suppression method thereof

Abstract

The invention discloses an intelligent ring system and a light interference suppression method thereof, and the system comprises a ring housing which is a circular ring with a ring cavity; the flexible printed circuit board is used for loading various electronic and non-electronic elements required by the ring system, and the flexible printed circuit board is arranged in the ring shell and is encapsulated and fixed through epoxy resin; the light-emitting module is composed of one or more wavelength light-emitting diodes, and the light-emitting module is coupled to the flexible printed circuit board; the light sensing module is composed of photodiodes, is coupled to the flexible printed circuit board and is matched with the light emitting module to complete PPG signal acquisition; the method has the beneficial effects that the optical crosstalk inside / outside the finger ring can be effectively inhibited, so that the quality of a finger PPG signal is optimized, the dependence on a signal processing algorithm is reduced, and finally the calculation accuracy of physiological indexes such as HR, SpO2, HRV and the like is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of smart rings, and in particular to a smart ring system and a method for suppressing light interference thereof. Background Art

[0002] With the advancement of technology and improved living standards, people are increasingly concerned about their health. Smart rings based on photoplethysmography (PPG) technology have become a rising star in the wearable electronics market due to their convenience, non-invasiveness, and continuous measurement capabilities. PPG technology is an absorptiometry method based on the Lambert-Beer law. Acquiring a PPG signal requires a light-emitting diode (LED) (light-emitting module) to illuminate tissue and a photodiode (PD) to receive the reflected / transmitted light, which contains information about tissue pulsation. Based on the acquired PPG signal, data processing and feature extraction can be used to calculate various physiological parameters such as heart rate (HR), blood oxygen saturation (SpO2), heart rate variability (HRV), and sleep stages. The accuracy of these metrics depends both on the accuracy of the algorithm and the quality of the raw PPG signal.

[0003] During actual signal acquisition, the PPG signal is highly susceptible to light interference, which primarily consists of two components. I: Light emitted by the light-emitting module couples directly to the PD without passing through tissue, affecting the DC component of the collected PPG signal and even causing signal link saturation. This interference can severely impact the calculation of physiological indicators that require a DC component, such as blood oxygen saturation. II: External light sources directly illuminate the PD, causing the collected PPG signal to include external light interference information such as ambient light fluctuations and fluorescent light flicker. This type of interference poses significant challenges to signal processing algorithms and ultimately affects the accuracy of the calculation of various physiological indicators.

[0004] Existing technologies generally reduce optical crosstalk by optimizing the fit between the sensor and the skin. However, ring packaging often uses a glue potting process, and its fillers such as epoxy resin, polyethylene, photosensitive adhesive and other transparent materials can still cause light leakage. At the same time, the extremely tight fit can also affect the wearing experience. In severe cases, it can even cause allergies and poor blood circulation. Summary of the Invention

[0005] The object of the present invention is to provide a smart ring system and a method for suppressing light interference thereof, so as to solve the problems raised in the above background technology.

[0006] To achieve the above objectives, the present invention provides the following technical solutions: a smart ring system, comprising: The ring housing is a circular ring with a ring cavity; A flexible printed circuit board (FPCB) is used to carry various electronic and non-electronic components required by the ring system. The FPCB is installed inside the ring housing and fixed by epoxy resin potting. A light emitting module, which is composed of one or more wavelength light emitting diodes and is coupled to a flexible printed circuit board; Light sensing module, which consists of a photodiode, coupled to a flexible printed circuit board and works with the light emitting module to complete PPG signal acquisition; Isolation light window, the isolation light window is an optical isolation element, which is installed on the periphery of the light-emitting module or light-sensing module to optimize the light path and reduce optical signal crosstalk.

[0007] An arc-shaped battery is placed inside the cavity of the ring and is electrically connected to the flexible printed circuit board, and is used to provide power for the smart ring system.

[0008] Preferably, it also includes electronic components, which are soldered on the flexible printed circuit board and include a microprocessor, a PPG signal analog front-end chip, a power management chip, a charging chip, and an antenna.

[0009] Preferably, the height of the isolated light window is higher than the light emitting module or the light sensing module and lower than the thickness of the ring cavity.

[0010] Preferably, the method for collecting the PPG signal is: The light-emitting module emits light and illuminates the signal collection part corresponding to the finger; The reflected or transmitted light is received by the light sensing module; The light sensing module converts the received light signal into a photocurrent, which is converted into a digital signal by the PPG signal analog front-end chip on the flexible printed circuit board; The digital signal is received, processed, and stored by the microprocessor and communicates with the outside world and transmits data via the antenna.

[0011] A method for suppressing optical interference, comprising: To prevent light interference from the same light source, an isolated light window with at least one light-through hole is used to effectively reduce the emission angle of the light-emitting module or the reception angle of the light-receiving module, thereby avoiding interference from the same light source and eliminating the DC component of the reflected / transmitted light that does not pass through the tissue and is directly coupled to the photodiode. For light interference from external light sources, the correlated double / triple sampling method is used for signal acquisition, and time-division multiplexing timing control logic is used for the signal acquisition link. The light interference signal is collected before / after the light-emitting module is lit, and the PPG signal containing the interference signal is collected when the light-emitting module is lit. Finally, the ambient light is subtracted from the PPG signal containing the interference signal to eliminate the interference of the external light source.

[0012] Compared with the prior art, the present invention has the following advantages: by using an isolated light window with at least one light-through hole, the emission angle of the light-emitting module or the reception angle of the light-receiving module can be effectively reduced, interference from the same light source can be avoided, and the DC component of the reflected / transmitted light that does not pass through the tissue and is directly coupled to the photodiode can be eliminated; the correlated double / triple sampling method is used for signal acquisition. This method adopts time-division multiplexing timing control logic for the signal acquisition link, collects light interference signals before / after the light-emitting module is lit, and collects PPG signals containing interference signals when the light-emitting module is lit, subtracts ambient light from the PPG signals containing interference signals, thereby eliminating interference from external light sources, and can effectively suppress internal / external light crosstalk in the ring, thereby optimizing the quality of the finger PPG signal, reducing dependence on signal processing algorithms, and ultimately improving the calculation accuracy of physiological indicators such as HR, SpO2, and HRV. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the smart ring system of the present invention; Figure 2 This is a schematic diagram of the assembly of the light-emitting module and the isolation light window in the present invention; Figure 3 This is a schematic diagram of the interference light suppression optical path optimization of the present invention; Figure 4 This is a timing diagram of correlated double / triple sampling of the present invention; Figure 5 Schematic diagram of PPG signal reconstruction using the present invention; In the figure, 100 is a smart ring system; 110 is a ring housing; 120 is an epoxy resin; 130 is a ring cavity; 140 is a flexible printed circuit board; 141 is a light sensing module; 142 is a light emitting module; 143 is an isolation light window; 144 is an electronic component; 150 is a curved battery; and 1421 is a light emitting diode. DETAILED DESCRIPTION

[0014] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0015] See also Figure 1-Figure 5 The present invention provides a technical solution: a smart ring system, comprising: The ring housing 110 is a circular ring having a ring cavity 130; Flexible printed circuit board 140, which is used to load various electronic and non-electronic components required by the ring system. It is installed inside the ring cavity 130 and is fixed by epoxy resin 120; The ring housing 110 , the epoxy resin potting layer 120 and the flexible printed circuit board 140 constitute the main body of the smart ring system 100 ; The epoxy resin encapsulation layer 120 may be provided with two convex lenses to reduce the relative rotation between the finger and the ring and optimize the light collection effect; The arc-shaped battery 150 is placed inside the ring cavity 130 and electrically connected to the flexible printed circuit board 140 to provide power to the smart ring system 100; The light sensing module 141 is coupled to the flexible printed circuit board 140 and is composed of a photodiode for receiving light signals.

[0016] The light sensing module 141 may be installed at a corresponding position of the flexible printed circuit board facing the convex lens to maximize the intensity of the received light signal.

[0017] The light emitting module 142 is mounted on the flexible printed circuit board 140 and is composed of a light emitting diode 1421. The isolation light window 143 is mounted outside the light emitting diode 1421 and has at least one light hole on the top.

[0018] The light emitting diode 1421 in the light emitting module 142 may be a multi-wavelength light emitting diode module composed of multi-wavelength light emitting diodes.

[0019] The isolation light window 143 is a light isolation element, which is installed on the periphery of the light emitting module 142 or the light sensing module 141 and fixed on the flexible printed circuit board 140 to optimize the light path and reduce optical signal crosstalk.

[0020] The height of the isolation light window 143 is greater than the height of the light emitting module 142 or the light sensing module 141 and smaller than the thickness of the ring cavity 130 .

[0021] The isolation light window may be made of silicone, plastic, sponge or metal.

[0022] Electronic components 144 are mounted on the flexible printed circuit board 140 , and include but are not limited to a microprocessor, a PPG signal detection chip, a power management chip, a charging chip, and an antenna.

[0023] The PPG signal acquisition link and signal acquisition process for the ring system include: S1: The light-emitting module 142 emits light and illuminates the signal collection part corresponding to the finger; S2: The reflected or transmitted light is received by the light sensing module 141; S3: The light sensing module 141 converts the received light signal into a photocurrent, which is then converted into a digital signal by the PPG signal analog front-end chip 144 on the flexible printed circuit board 140; S4: The digital signal is received, processed, and stored by the microprocessor and communicates with the outside world and transmits data via the antenna.

[0024] A method for suppressing optical interference, comprising: S1: An isolated light window 143 with at least one light-through hole is installed around the light-emitting module 142 or light-sensing module 141. This isolation window is taller than the enclosed light-emitting module 142 or light-sensing module 141. This effectively reduces the light divergence angle of the light-emitting module and the light reception angle of the light-receiving module, cuts off direct optical coupling from the light-emitting module 142 to the light-sensing module 141, and prevents light interference from within the ring. This eliminates the unmodulated DC component of the photocurrent and improves the accuracy of physiological calculations that require DC information from the photocurrent.

[0025] S2: Correlated double / triple sampling is used to deal with external light interference. Specifically, when the PPG signal acquisition action occurs, the light interference signal generated by the current external light source is first collected, that is, the ambient light is collected (such as Figure 4 ), from which the ambient light signal can be obtained (as shown in Figure 5 Then, the light emitting module 142 is turned on to collect the finger PPG signal (as shown in FIG. Figure 4 As shown in 220 in FIG), the original PPG signal including the interference signal can be obtained (as shown in FIG. Figure 5 ); S3: The collected ambient light signal (such as Figure 5 320 in FIG) from the original PPG signal as (as shown in FIG) Figure 5 By eliminating the ambient light (shown as 310 in FIG), the PPG signal after the ambient light is eliminated can be obtained (as shown in FIG. Figure 5 As shown in 330 in FIG. 1 ). This can significantly reduce the impact of external light source interference on signal quality.

[0026] Among them, the external light source interferes with the acquisition phase (such as Figure 4 210) and the PPG signal acquisition phase (as shown in FIG. Figure 4 The time interval of the PPG signal (shown as 220 in FIG. 220 ) should be as small as possible, such as 10 microseconds, so that it can be effectively included in the original PPG signal ( Figure 5 310 in FIG) is eliminated without generating additional harmonics.

[0027] Among them, when the frequency of external light interference is too high, the correlated double sampling based on the front-end external light interference collection may not be able to effectively eliminate the external light interference due to insufficient sampling interval. At this time, the correlated triple sampling method can be used for signal collection; specifically, at equal intervals before and after the light-emitting module 142 is lit, the external interference light collection phase (such as Figure 4 As shown in 210 and Figure 4 The smaller the time interval, the better. The two collected interference signals are averaged and then removed from the original PPG signal to address high-frequency external interference light, thereby obtaining a more accurate original PPG signal.

[0028] In the description of the present invention, it should be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "the other end", "upper", "one side", "top", "inside", "front", "center", "both ends", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0029] In addition, the terms "first", "second", "third" and "fourth" are used for descriptive purposes only and cannot be understood as indicating or suggesting relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", "third" and "fourth" may explicitly or implicitly include at least one such feature.

[0030] In the present invention, unless otherwise clearly stipulated and limited, the terms "install", "set", "connect", "fix", "screw" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0031] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A smart ring system, characterized in that: include: A finger ring housing (110), wherein the finger ring housing (110) is a circular ring having a finger ring cavity (130); A flexible printed circuit board (140), the flexible printed circuit board (140) is installed inside the finger ring housing (110) and is fixed by encapsulation with epoxy resin (120); A light emitting module (142), the light emitting module (142) is composed of one or more light emitting diodes (1421) of multiple wavelengths and is coupled to a flexible printed circuit board (140); A light sensing module (141), the light sensing module (141) is composed of a photodiode, which is coupled to a flexible printed circuit board (140) and is used to cooperate with the light emitting module (142) to complete PPG signal acquisition; An isolation light window (143), the isolation light window (143) is installed on the periphery of the light emitting module (142) or the light sensing module (141) and is used to optimize the light path; The arc-shaped battery (150) is placed inside the ring cavity (130) and is electrically connected to the flexible printed circuit board (140), and is used to provide electrical energy for the smart ring system.

2. The smart ring system according to claim 1, characterized in that: It also includes an electronic component (144), which is soldered on the flexible printed circuit board (140). The electronic component (144) includes a microprocessor, a PPG signal analog front-end chip, a power management chip, a charging chip, and an antenna.

3. The smart ring system according to claim 2, characterized in that: The isolation light window (143) is made of a non-light-transmitting material and has at least one light-through hole. Its height is higher than the light-emitting module (142) or the light-sensing module (141) and lower than the thickness of the ring cavity (130).

4. The smart ring system according to claim 3, characterized in that: The method for collecting the PPG signal is: The light emitting module (142) emits light and illuminates the signal collection portion corresponding to the finger; The reflected or transmitted light is received by the light sensing module (141); The light sensing module (141) converts the received light signal into a photocurrent, which is converted into a digital signal by the PPG signal analog front-end chip on the flexible printed circuit board (140); The digital signal is received, processed, and stored by the microprocessor and communicates with the outside world and transmits data via the antenna.

5. The method for suppressing light interference of a smart ring system according to claim 4, characterized in that: The method comprises: For light interference from the same light source, an isolation light window (143) including at least one light-through hole is used to effectively reduce the emission angle of the light-emitting module (142) or the reception angle of the light-receiving module, thereby avoiding interference from the same light source and eliminating the DC component of the reflected / transmitted light that does not pass through the tissue and is directly coupled to the photodiode; For light interference from external light sources, a correlated double / triple sampling method is used for signal acquisition, and a time-division multiplexing timing control logic is used for the signal acquisition link. The light interference signal is collected before / after the light-emitting module (142) is turned on, and a PPG signal containing the interference signal is collected when the light-emitting module (142) is turned on. Finally, the ambient light is subtracted from the PPG signal containing the interference signal, thereby eliminating the interference of the external light source.

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