CN114403823A

CN114403823A - Heart rate blood oxygen detection method and device and wearable device

Info

Publication number: CN114403823A
Application number: CN202210065910.2A
Authority: CN
Inventors: 龚永兴; 聂佳强
Original assignee: Hangzhou Najing Technology Co ltd
Current assignee: Hangzhou Najing Technology Co ltd
Priority date: 2022-01-20
Filing date: 2022-01-20
Publication date: 2022-04-29

Abstract

The invention relates to the technical field of detection, and particularly discloses a heart rate blood oxygen detection method, a heart rate blood oxygen detection device and wearable equipment, wherein the method comprises the following steps: the method comprises the following steps of arranging at least two light source emitters, wherein light rays emitted by the two light source emitters are red light and infrared light respectively; light emitted by the light source emitter is transmitted to the light receivers, the light receivers correspond to the light source emitters one to one, the light source emitters and the light receivers are integrated with superlenses, and the light receivers convert collected light signals into electric signals; the electric signal is output to a processing module, the processing module obtains the signal intensity of the optical receiver, and after sufficient signal intensity is obtained, algorithm software is used for calculating and obtaining a corresponding value. This application has realized the collection of LED light beam at the focus of human blood vessel and high efficiency LED reflection transmission light beam, compares in traditional rhythm of the heart blood oxygen sensor, and integrated super lens can greatly reduce the equipment volume, and convenient integration advances small-size wearable equipment.

Description

Heart rate blood oxygen detection method and device and wearable device

Technical Field

The invention belongs to the technical field of detection, and particularly relates to a heart rate blood oxygen detection method and device and wearable equipment.

Background

In recent years, with the increasing interest of people on health, the demand of monitoring heart rate and blood oxygen of a human body in real time is gradually increased. In combination with the vigorous development of current consumer electronics, it has become a great trend to integrate a sensor for monitoring heart rate and blood oxygen of a human body in real time into a wearable electronic product, wherein the wearable electronic product comprises a mobile phone, a bracelet, a watch, an earphone, glasses and the like. These consumer electronics have in common that they are small, which means that the space that we can integrate the heart rate blood oxygen detector is small, and thus it poses certain challenges to the preparation of the heart rate blood oxygen sensor.

Meanwhile, with the rise of the sports industry, sports become an indispensable part of the life of people. The heart rate and blood oxygen condition of the human body can be changed along with the motion state of the human body, for example, the heart rate is increased and the blood oxygen content is slightly reduced in the motion process, so that the real-time monitoring of the heart rate and blood oxygen condition of the human body in the motion process has greater practical significance, and especially, the early warning effect can be achieved for patients suffering from heart diseases or cardiovascular diseases.

However, carry on heart rate blood oxygen sensor on bracelet or wrist-watch at present can't avoid all the time because wear the inaccurate problem of measurement accuracy that has different elasticity degrees and lead to, simultaneously at the human motion in-process, because the different degree of bracelet and wrist-watch rocks, lead to introducing the error in the measurement process, so will be more favorable to improving measurement accuracy with heart rate blood oxygen detector integration on the higher earphone of stability or glasses, but the space that can supply to carry on heart rate blood oxygen detector on earphone and the glasses is littleer for cell-phone and bracelet, so further the preparation of heart rate blood oxygen detector has provided the challenge.

Disclosure of Invention

The application provides a heart rate blood oxygen detection method, a sensor and wearable equipment, which are used for at least solving the technical problems in the prior art.

The embodiment of the application provides a heart rate blood oxygen detection method, which comprises the following steps: arranging at least two light source emitters; when the number of the light sources is two, the light rays emitted by the two light source emitters are red light and infrared light respectively; the light emitted by the light source emitter is transmitted to the light receivers, the light receivers are in one-to-one correspondence with the light source emitters, the light source emitters and the light receivers are integrated with superlenses, and the light receivers convert collected light signals into electric signals; and the electric signal is output to a processing module, the processing module acquires the signal intensity received by the optical receiver, and after sufficient signal intensity is acquired, algorithm software is used for calculating and obtaining a corresponding value.

In one embodiment, the number of the superlenses is one or four.

In one embodiment, the light emitter emits 660nm red light and 860nm infrared light.

In one embodiment, detecting the heart rate comprises the steps of:

a1, running algorithm software and acquiring PPG signals at the frequency of 100-300 Hz;

a2, judging whether the number of the collected signals is enough;

if the number of the collected signals is insufficient, continuing to collect the signals;

and A3, smoothing the acquired PPG signal by using algorithm software, and calculating the number of the PPG signal cycles in unit time to calculate a heart rate value.

In one embodiment, the blood oxygen detection comprises the following steps:

b1, running algorithm software and acquiring PPG signals at the frequency of 100-300 Hz;

b2, judging whether the number of the collected signals is enough;

b3, smoothing the collected PPG signal by using algorithm software, and calculating to obtain an R value;

b4, repeating B1-B3 for multiple times to respectively obtain corresponding R values, and taking the average value of all the R values to calculate and obtain the blood oxygen saturation value.

The embodiment of the application also provides a heart rate blood oxygen detection device, which comprises a light source emitter, an optical receiver and a reading circuit; the number of the light source emitters is at least two; when the number of the light sources is two, the light rays emitted by the two light source emitters are 660nm red light and 860nm infrared light respectively, the light emitted by the light source emitters is transmitted to the light receiver, and the light receiver is integrated with a superlens; the reading circuit is electrically connected with the optical receiver and receives the electric signal transmitted by the optical receiver.

In one embodiment, the substrate material used for preparing the light source emitter is a dielectric material transparent in both near infrared band and visible light band; the dielectric material is any one of silicon dioxide, titanium dioxide, silicon nitride, polymethyl methacrylate and polydimethylsiloxane.

The embodiment of the present application further provides a wearable device, which includes any of the above heart rate blood oxygen detection devices in the implementation manners.

The heart rate blood oxygen detection method and device and wearable equipment provided by the embodiment of the application have the characteristics of miniaturization, low energy consumption and high stability, and are favorable for installing the heart rate blood oxygen detection device in the wearable equipment with smaller volume. And this application has realized the collection of LED light beam at the focus of human blood vessel and high efficiency LED reflection transmission light beam, compares in adopting traditional heart rate blood oxygen sensor, and integrated super lens can greatly reduce the equipment volume, improves the focusing efficiency of transmission light and the collection efficiency of reverberation, conveniently integrates into small-size wearable equipment.

Drawings

FIG. 1 is a schematic diagram of a heart rate blood oxygen detector according to an embodiment of the present application;

FIG. 2 is a schematic diagram of a heart rate blood oxygen detector with four superlenses according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of the optical path of the heart rate blood oxygen detector in the embodiment of the present application;

FIG. 4 is a schematic structural diagram of a light beam emitting module in an embodiment of the present application;

FIG. 5 is a schematic structural diagram of a light beam receiving module in an embodiment of the present application;

fig. 6 is a schematic structural diagram of a heart rate blood oxygen detector when the number of superlenses is one in the embodiment of the present application.

Detailed Description

In order to make the objects, features and advantages of the present disclosure more apparent and understandable, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present disclosure, and it is apparent that the described embodiments are only a part of the embodiments of the present disclosure, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments disclosed herein without making any creative effort, shall fall within the protection scope of the present disclosure.

The inventor of the present application finds that most of the principles of heart rate and blood oxygen detectors on the market at present are based on photoplethysmography (PPG) for detection, and the main principles are as follows: the light path is formed by the emitter and the receiver, and the heart rate and the blood oxygen content of the human body at the moment are calculated in real time by detecting different absorption quantities of human body tissues (such as muscles, bones, veins, arteries and the like) to different wavelengths of light.

Normally, the amount of absorption of incident light by bones, skin and muscles in human tissue is constant, constituting a direct current component in the output electrical signal, while the change in blood volume in blood vessels due to cardiac contraction will change the amount of light absorption, thereby producing fluctuations in the direct current component, constituting an alternating current component in the electrical signal. For example, reduced hemoglobin (Hb) has a high absorbance at 660nm and a low absorbance at 860nm, and oxygenated hemoglobin (HbO) in humans₂) On the contrary, the absorbance for infrared light is high and the absorbance for red light is low, and by using the difference of the absorbances, Hb and HbO in the blood vessel of the human body can be measured₂The content of the red light in the blood oxygen saturation value is calculated, and meanwhile, the heart rate of the human body can be accurately detected through extraction and analysis of a PPG signal according to the periodic change condition of the red light absorption rate of the Hb.

The receiver is generally used for receiving optical signals reflected or transmitted by fingers, thereby characterizing the absorptivity of the human body to light of different wave bands. The scattering effect of the oxygenated hemoglobin and the reduced hemoglobin in the blood on the light causes the light signal received by the receiver to be weaker, and the detectable light signal is usually enhanced by increasing the emission intensity of the light source or increasing the number of the receivers, but the power consumption and the volume of the device are increased by the method.

In addition, light scattering signals of other wavebands will also interfere with detection of heart rate and blood oxygen, and at present, filtering processing can be performed on an electric signal converted from a light signal through a filtering circuit, and if an optical filtering mode can be adopted at the source of the filtering circuit, interference of stray light is filtered, and great help is generated for circuit optimization.

The detection principle of the heart rate is as follows:

in a normal human body, the waveform of one pulse signal period can correspond to the process of one heart beat, so the waveform diagram detected by the PPG principle is a waveform with periodic change, and the heart rate of the human body can be accurately extracted from the waveform period containing several waveform periods per second. For example, the PPG signal appears for N cycles in F seconds, the cycle number of the PPG signal is N/F in unit time, and then the human heart rate at the moment is calculated to be 60N/F.

Wherein, the detection principle of blood oxygen is as follows:

the detection of the blood oxygen saturation of the human body means that the volume of the oxyhemoglobin of the human body accounts for the proportion of the total combinable hemoglobin. The detection method of the blood oxygen saturation based on the PPG is essentially based on the difference of the absorption coefficients of oxyhemoglobin and reduced hemoglobin to red light and infrared light, so that the blood oxygen saturation of a human body is accurately estimated according to the ratio of the detected signal intensities under two different wavelengths. Wherein the calculation formula of the blood oxygen saturation can be expressed as:

。

wherein

Wherein

And

the amplitude of the ith periodic signal detected at two wavelengths, A, B and C, are calibrated according to different usersThe same constant. Therefore, according to the formula, the optical signal detected by the PPG can be accurately converted into the human blood oxygen saturation.

In an implementation manner, based on the above heart rate and blood oxygen detection principle, the heart rate blood oxygen detection method provided by the present application, as shown in fig. 1, includes:

and S1, arranging at least two light source emitters. The light that the light source transmitter transmitted spreads to light receiver, and light receiver and light source transmitter one-to-one correspond all integrate on light source transmitter and the light receiver and have super lens. Reference is made to the following description regarding the specific structure of the light source emitter, the light receiver and the superlens.

S2, running algorithm software and acquiring PPG signals at the frequency of 100-300Hz to judge whether the number of the acquired signals is enough; and if the number of the collected signals is not enough, continuing to collect the signals.

S3, smoothing the acquired PPG signal by using algorithm software;

when detecting the heart rate: calculating the PPG signal periodicity in unit time to obtain a heart rate value;

when detecting blood oxygen: and calculating the R value, repeating the step S2 for multiple times to obtain the corresponding R value, and then taking the average value of all the R values to calculate the blood oxygen saturation value.

In one embodiment, the heart rate blood oxygen detecting device is manufactured by the following manufacturing method.

Wherein, heart rate blood oxygen detection device includes: the device comprises two light source transmitters, two light receivers, a superlens, a reading circuit and a software processing module.

The light emitted by the two light source emitters is 660nm red light and 860nm infrared light, i.e. the two light source emitters are red light source emitter 12 and infrared light source emitter 14.

The red light source emitter 12 and the infrared light source emitter 14 can both adopt small-sized common LED light sources on the market, and are combined with different wearable devices to design different focal lengths for the super lens of the small-sized LED light sources.

The two light receivers respectively receive the light beams of the two light source transmitters, namely a red light receiver 16 and an infrared light receiver 18.

The light source emitter and the light receiver are both integrated with super lenses, and the number of the super lenses can be one or four.

In an embodiment, referring to fig. 2, the number of the superlenses is four, and the red light source emitter 12, the infrared light source emitter 14, the red light receiver 16 and the infrared light receiver 18 are respectively and correspondingly integrated with a first superlens 11, a second superlens 13, a third superlens 15 and a fourth superlens 17.

Wearable equipment can be earphone, wrist-watch etc. to the earphone is the example, and this type of product is comparatively inseparable with human skin is attached, and it is less to relate to the focus, can design the focus and be 8-12mm, designs super lens phase place according to super lens phase place computational formula and distributes:

wherein x and y are superlens superatomic coordinates,

the incidence angles of the oblique incidence beams and the x-axis and the y-axis are included, f is the focal length of the designed super lens, lambda is the incident light wavelength,

，

。

similarly, the phase distribution of the superlens of the optical receiver is determined according to the different wavelengths of the received light and the focal length of the superlens, and according to the designed reflection angle of the light beam on the optical path, above the red light optical receiver 16 and the infrared light optical receiver 18. In the embodiment, the earphone is taken as an example, in the structure of an earphone product, the gap between the optical receiver and the light source emitter is small, about 3-5mm, and the light beam emission and reflection angle in the designed light path can be estimated to be about 10 degrees by combining the focal length of the designed superlens at the moment, so that the phase distribution condition of each position of the superlens can be accurately calculated according to the parameters and the formula, and the size condition of the superatom at each position can be obtained and used as the data support for preparing the superlens.

Selecting substrate material silicon dioxide (SiO) of light source emitter according to the obtained super-atomic size of each position of super lens₂) As a base material, if the light source emitter substrate material is other opaque materials, the substrate needs to be removed first, then a layer of transparent base is re-grown on the light source emitter substrate by using a chemical vapor deposition method, the material can be silicon dioxide, titanium dioxide, silicon nitride, polymethyl methacrylate, polydimethylsiloxane and other common transparent base materials, the thickness is about 1mm (the size can be further reduced according to the actual situation of the size in the earphone), then a layer of silicon (Si) film is grown on the lower surface of the light source emitter substrate by using a plasma enhanced chemical vapor deposition method, and then the super-atom which meets the size design of people is prepared on the Si film by using a photoetching technology according to the super-atom size.

Similarly, the same processing method is adopted for the light receiver, a layer of substrate material is grown on the photosensitive piece of the light receiver by using a chemical vapor deposition method, and then the super atoms which are in accordance with the expected design are prepared on the substrate material, so that the first super lens 11, the second super lens 13, the third super lens 15 and the fourth super lens 17 which are in accordance with the design are obtained.

The first superlens 11 and the red light source emitter 12 form a first light emitting module 21, the second superlens 13 and the infrared light source emitter 14 form a second light emitting module 22, the third superlens 15 and the red light receiver 16 form a first light receiving module 23, and the fourth superlens 17 and the infrared light receiver 18 form a second light receiving module 24.

Thus, a first light emitting module 21 and a second light emitting module 22 for focusing light beams in the blood vessel of the human body and a first light receiving module 23 and a second light receiving module 24 for efficiently collecting reflected light reflected by the blood are prepared, and the structure diagram of the brief light path for light beam emission and collection is shown in fig. 3.

Fig. 4 shows a conventional structure of a light source emitter used, which includes a metal cathode electrode 31 of the LED light source emitter, an electron transport layer 32, a light emitting layer 33, a hole transport layer 34, an ITO film (indium tin oxide film) 35, and a superlens substrate 36, and a superlens 37 is formed or integrated on the LED light source emitter.

Fig. 5 shows a conventional structure of an optical receiver used, which mainly includes an optical receiver reading circuit 41, an optical receiver CMOS chip 42, and an optical receiver super lens substrate 43, and a super lens is grown or integrated on the optical receiver substrate.

Meanwhile, the reading circuit 19 in the schematic structural diagram includes an integrated board for various signal processing, and can process and output the electrical signal response received in the optical receiver.

The software processing module 20 contains an algorithm for processing the PPG signal, and writes an algorithm program for calculating heart rate and blood oxygen according to the above principle formula, or directly processes the PPG signal output by the reading circuit 19 by using a relatively mature commercial heart rate blood oxygen calculation program, thereby obtaining the specific heart rate blood oxygen parameter of the human body. The processing software is generally integrated in a mobile phone connected with the earphone and Bluetooth, and signals processed by the processing software are displayed through a mobile phone APP.

In one possible embodiment, referring to fig. 6, the number of superlenses is one, the superlens is a broadband superlens 61, and the broadband superlens 61 covers the areas where the red light source emitter 12, the infrared light source emitter 14, the red light receiver 16 and the infrared light receiver 18 are located.

Compared with the implementation mode that the number of the super lenses is four, the implementation mode simplifies the manufacturing process of the super lenses and the manufacturing process of the whole heart rate blood oxygen detector.

Two preparation schemes are provided below:

(1) the broadband super lens 61 is divided into 4 areas, each area is designed into a super lens according to the emission and collection focal length of red light and infrared light, and SiO is also selected₂And as a substrate, growing a Si film on the substrate by using a plasma enhanced chemical vapor deposition technology, and preparing the superlens meeting the design requirement on the Si film by using a photoetching or electronic etching technology.

(2) In the superlensThe implementation mode with four is improved, the phase reconstruction unit of the original focusing super lens is divided into two parts, a basic phase unit irrelevant to wavelength and a compensation phase unit relevant to wavelength, the focusing broadband super lens in 660nm and 860nm wave bands is designed through the two relatively independent phase modulation units, and the SiO is also selected₂And as a substrate, growing a Si film on the substrate by using a plasma enhanced chemical vapor deposition technology, and preparing the superlens meeting the design requirement on the Si film by using a photoetching or electronic etching technology.

After the superlens is successfully prepared, the superlens is integrated above the two light emitters and the light receiver by utilizing a semiconductor processing technology, so that the preparation of the heart rate blood oxygen detector is completed, wherein the light emitters and the light receiver can also adopt small LED light sources and small photoelectric sensors which are common in the market.

The subsequent reading circuit 19 includes an integrated board for various signal processing, and can process the electrical signal response received in the optical receiver and output the processed signal.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present disclosure, "a plurality" means two or more unless specifically limited otherwise.

The above is only a specific embodiment of the present disclosure, but the scope of the present disclosure is not limited thereto, and any person skilled in the art can easily conceive of changes or substitutions within the technical scope of the present disclosure, and shall be covered by the scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.

Claims

1. A method of heart rate oximetry, the method comprising:

arranging at least two light source emitters;

when the number of the light sources is two, the light rays emitted by the two light source emitters are red light and infrared light respectively;

the light emitted by the light source emitter is transmitted to the light receivers, the light receivers are in one-to-one correspondence with the light source emitters, the light source emitters and the light receivers are integrated with superlenses, and the light receivers convert collected light signals into electric signals;

and the electric signal is output to a processing module, the processing module acquires the signal intensity received by the optical receiver, and after sufficient signal intensity is acquired, algorithm software is used for calculating and obtaining a corresponding value.

2. The heart rate blood oxygen detection method according to claim 1, characterized in that: the number of the superlenses is one or four.

3. The heart rate blood oxygen detection method according to claim 1, characterized in that: the light emitted by the light source emitter is 660nm red light and 860nm infrared light.

4. The method for detecting heart rate blood oxygen as claimed in claim 1,

detecting the heart rate comprises the following steps:

a2, judging whether the number of the collected signals is enough;

5. The method for detecting heart rate blood oxygen as claimed in claim 1,

the blood oxygen detection method comprises the following steps:

b2, judging whether the number of the collected signals is enough;

6. A heart rate blood oxygen detection device is characterized by comprising a light source emitter, a light receiver and a reading circuit;

the number of the light source emitters is at least two; when the number of the light sources is two, the light rays emitted by the two light source emitters are 660nm red light and 860nm infrared light respectively, the light emitted by the light source emitters is transmitted to the light receiver, and the light receiver is integrated with a superlens;

the reading circuit is electrically connected with the optical receiver and receives the electric signal transmitted by the optical receiver.

7. The heart rate oximetry device of claim 6, wherein: the substrate material for preparing the light source emitter is a dielectric material with transparent near infrared wave band and visible light wave band;

the dielectric material is any one of silicon dioxide, titanium dioxide, silicon nitride, polymethyl methacrylate and polydimethylsiloxane.

8. A wearable device, characterized by comprising a heart rate blood oxygen detection device according to any one of claims 6-7.