WO2023103485A1 - 光电探测器、ppg传感器及电子设备 - Google Patents

光电探测器、ppg传感器及电子设备 Download PDF

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WO2023103485A1
WO2023103485A1 PCT/CN2022/116614 CN2022116614W WO2023103485A1 WO 2023103485 A1 WO2023103485 A1 WO 2023103485A1 CN 2022116614 W CN2022116614 W CN 2022116614W WO 2023103485 A1 WO2023103485 A1 WO 2023103485A1
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Prior art keywords
light
photodiode
signal
filter part
ppg
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PCT/CN2022/116614
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English (en)
French (fr)
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谭银炯
尚睿颖
刘炳鑫
蔡辛培
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荣耀终端有限公司
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Priority to US18/043,841 priority Critical patent/US20240324955A1/en
Priority to EP22857109.7A priority patent/EP4215108A4/en
Publication of WO2023103485A1 publication Critical patent/WO2023103485A1/zh

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
    • A61B5/024—Detecting, measuring or recording pulse rate or heart rate
    • A61B5/02416—Detecting, measuring or recording pulse rate or heart rate using photoplethysmograph signals, e.g. generated by infrared radiation
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
    • A61B5/6801—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be attached to or worn on the body surface
    • A61B5/6802—Sensor mounted on worn items
    • A61B5/681—Wristwatch-type devices
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
    • A61B5/024—Detecting, measuring or recording pulse rate or heart rate
    • A61B5/02416—Detecting, measuring or recording pulse rate or heart rate using photoplethysmograph signals, e.g. generated by infrared radiation
    • A61B5/02427—Details of sensor
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
    • A61B5/024—Detecting, measuring or recording pulse rate or heart rate
    • A61B5/02416—Detecting, measuring or recording pulse rate or heart rate using photoplethysmograph signals, e.g. generated by infrared radiation
    • A61B5/02427—Details of sensor
    • A61B5/02433—Details of sensor for infrared radiation
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
    • A61B5/1455—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
    • A61B5/14551—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters for measuring blood gases
    • A61B5/14552—Details of sensors specially adapted therefor
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
    • A61B2562/02—Details of sensors specially adapted for in-vivo measurements
    • A61B2562/0233—Special features of optical sensors or probes classified in A61B5/00
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
    • A61B2562/02—Details of sensors specially adapted for in-vivo measurements
    • A61B2562/0233—Special features of optical sensors or probes classified in A61B5/00
    • A61B2562/0238—Optical sensor arrangements for performing transmission measurements on body tissue

Definitions

  • the present application relates to the field of biosensing, in particular, to photodetectors, photoplethysmography (photo plethysmograph, PPG) sensors and electronic devices.
  • PPG photo plethysmograph
  • the first aspect of the present application provides a photodetector, which includes:
  • a photodiode for sensing light in the first, second, and third wavelength bands
  • At least one first filter part located on the photodiode, is used to transmit the light of the first wavelength band and the second wavelength band, and block the light of the third wavelength band;
  • At least one second filter part located on the photodiode, is used to pass through the light of the third waveband and block the light of the first waveband and the second waveband.
  • the photodiode by providing the first filter part and the second filter part, the photodiode can relatively decouple the detection of the light of the first waveband and the second waveband from the detection of the light of the third waveband. That is, the photodetector can detect light in the first and second wavelength bands by using the region where the photodiode is provided with the first filter part, and detect light in the third waveband by using the region where the photodiode is provided with the second filter part.
  • the photodetector detects light in the first and second wavelength bands
  • the light in the third waveband will be blocked by the first filter and cannot enter the photodiode, so the influence of the light in the third waveband can be avoided , reducing the noise of detecting the light of the first waveband and the second waveband, thereby improving the signal-to-noise ratio of detecting the light of the first waveband and the second waveband.
  • the photodetector detects the light of the third waveband, the light of the first waveband and the second waveband will be blocked by the second filter part and cannot enter the photodiode, therefore, the light of the first waveband and the second waveband can be avoided. Influenced by the light in the third waveband, the noise of detecting the light in the third waveband is reduced, thereby improving the signal-to-noise ratio in detecting the light in the third waveband.
  • the first waveband is within the red spectrum
  • the second waveband is within the infrared spectrum
  • the third waveband is within the green light spectrum. That is, red light, infrared light, and green light can all be sensed by the photodiode.
  • the first filter part can selectively transmit red light and infrared light and block green light.
  • the second filter part can selectively transmit green light and block red light and infrared light. Therefore, the area of the photodiode covered by the first filter part can receive red light and infrared light, but not green light; the area of the photodiode covered by the second filter part can receive green light, but not red light and infrared light Light.
  • the difference between the projected area of the at least one first filter part on the photodiode and the projected area of the at least one second filter part on the photodiode The ratio is 1: (1.6 ⁇ 1.3).
  • the photodiode is a full-spectrum sensitive photodiode that is not as sensitive to red and infrared light as it is to green light. Specifically, the ratio between the sensitivity of the photodiode to red light and infrared light and the sensitivity of the photodiode to green light is approximately (1.6 ⁇ 1.3):1.
  • the ratio of photogenerated current generated is (1.6-1.3):1.
  • the ratio of the total projected area of all first filter parts on the photodiode to the total projected area of all second filter parts on the photodiode is 1: (1.6 ⁇ 1.3) , so that the photogenerated current produced by the photodetector when irradiated with red light and infrared light with an irradiance of 1mW/cm2 is roughly equivalent to the photogenerated current generated by the photodetector when irradiated with green light with an irradiance of 1mW/cm2.
  • the number of the first filter part and the second filter part are the same, and along the thickness direction of the photodiode, the projected area of each first filter part on the photodiode is equal to that of each second filter part.
  • the ratio of the projected area of the light portion on the photodiode is 1:(1.6 ⁇ 1.3).
  • the projected area of each first filter portion on the photodiode is the same as the projected area of each second filter portion on the photodiode, the first The ratio of the number of the filter part to the second filter part is 1: (1.6 ⁇ 1.3). That is, the total area of all the first filter parts can be adjusted by adjusting the number of the first filter part and the second filter part, or the size of the area of each first filter part and the second filter part The ratio to the total area of all the second filter parts.
  • a plurality of first filter parts and a plurality of second filter parts are arranged in a matrix in multiple rows and columns; in multiple rows and multiple columns, each row has a first filter part and a second filter part.
  • the filter parts are arranged alternately and periodically, and each column is a first filter part and a second filter part which are arranged alternately and periodically.
  • the projection of the first filter part on the photodiode is a rectangle
  • the projection of the second filter part on the photodiode is a rectangle.
  • the shapes and arrangement rules of the first filter part and the second filter part are not limited thereto.
  • the number of the first filter part and the second filter part are the same, and along the thickness direction of the photodiode, the width of the rectangle formed by the projection of the first filter part on the photodiode is equal to that of the second filter part.
  • the width of the rectangle formed by the projection of the light part on the photodiode is the same, and the length of the rectangle formed by the projection of the first filter part on the photodiode is the same as the length of the rectangle formed by the projection of the second filter part on the photodiode.
  • the length ratio is 1:(1.6 ⁇ 1.3).
  • the photodetector further includes a circuit substrate, and the photodiode is electrically connected to the circuit substrate.
  • the circuit substrate is, for example, a printed circuit board, and the photodiodes are electrically connected to the circuit substrate through wires, such as gold wires, but not limited thereto.
  • the photodetector further includes an encapsulation layer, and the encapsulation layer covers the photodiode, the first filter part and the second filter part.
  • the material of the encapsulation layer is, for example, epoxy resin, but not limited thereto.
  • the second aspect of the present application provides a PPG sensor, which includes:
  • the first light source is used to emit a first light signal, and the light reflected by the user's skin/tissue of the first light signal is at least partly in the first wavelength band;
  • the second light source is used to emit a second light signal, and the light reflected by the second light signal from the user's skin/tissue is at least partly in the second wavelength band;
  • the third light source is used to send out a third light signal, and the light reflected by the third light signal from the user's skin/tissue is at least partly in the third waveband;
  • the photodetector is used to receive the light of the first waveband and generate the first PPG signal, receive the light of the second waveband and generate the second PPG signal, receive the light of the third waveband and generate the third PPG signal, the first PPG signal, The second PPG signal and the third PPG signal are used to detect the physiological characteristics of the user.
  • the PPG sensor includes the photodetector of the first aspect. Since the photodetector is provided with a first filter part and a second filter part, the detection of the light of the first waveband and the second waveband by the photodiode can be compared with that of the third waveband. The detection of the light bands is relatively decoupled. That is, the photodetector can detect light in the first and second wavelength bands by using the region where the photodiode is provided with the first filter part, and detect light in the third waveband by using the region where the photodiode is provided with the second filter part.
  • the photodetector detects light in the first and second wavelength bands
  • the light in the third waveband will be blocked by the first filter and cannot enter the photodiode, so the influence of the light in the third waveband can be avoided , reducing the noise of detecting the light of the first waveband and the second waveband, thereby improving the signal-to-noise ratio of detecting the light of the first waveband and the second waveband, so that the detection of the first PPG signal and the second PPG signal is more accurate.
  • the photodetector detects the light of the third waveband
  • the light of the first waveband and the second waveband will be blocked by the second filter part and cannot enter the photodiode, therefore, the light of the first waveband and the second waveband can be avoided.
  • the influence of the light in the third waveband reduces the noise of detecting the light in the third waveband, thereby improving the signal-to-noise ratio in detecting the light in the third waveband, so that the detection of the third PPG signal is more accurate. In this way, the data of the user's physiological characteristics detected according to the first PPG signal, the second PPG signal and the third PPG signal are more accurate.
  • the PPG sensor includes a light source group
  • the light source group includes a first light source, a second light source and a third light source
  • a plurality of photodetectors are arranged at intervals around the light source group.
  • the PPG sensor includes a plurality of light source groups arranged at intervals.
  • the setting of multiple light source groups enables the photodetector to detect light from different light source groups, thereby avoiding the problem of inaccurate detection results caused by differences in the user's biological tissue or wearing habits, thereby improving the accuracy of the user's biological information detection.
  • the physiological characteristics include blood oxygen saturation and heart rate
  • the first light signal is red light
  • the second light signal is infrared light
  • the first PPG signal and the second PPG signal are used to detect the blood oxygen saturation of the user
  • the third light signal is green light
  • the third PPG signal is used to detect the user's heart rate.
  • the detection of heart rate mainly uses green light, because the signal-to-noise ratio of PPG measured by green light is high, and the requirements for detection and signal conditioning are relatively low, even if there is some interference (such as sports), it is easier to eliminate.
  • the detection of blood oxygen saturation mainly uses red light and infrared light.
  • hemoglobin and oxyhemoglobin in the blood have different absorption rates for red light and infrared light.
  • Oxyhemoglobin absorbs more near-infrared light (around 900nm), while Hemoglobin absorbs more red light (around 650nm), and this difference in absorption of red light and infrared light can be used to measure the value of blood oxygen saturation. Therefore, red light and near-infrared light can be used to detect the PPG signals of oxyhemoglobin and hemoglobin in the human body, and then the corresponding ratio between oxyhemoglobin and hemoglobin can be obtained through the PPG signal, so that the blood oxygen saturation of the human body can be obtained Spend.
  • the third aspect of the present application provides an electronic device, which includes the PPG sensor of the second aspect.
  • the electronic device may be a wrist wearable device (such as a smart watch, a smart bracelet), a head-mounted device (such as a smart helmet), a clothing device (such as a smart clothing, a smart glove, an armband), and the like.
  • the electronic device may also be a device with a health detection function, such as a blood oxygen meter, a heart rate detector, and the like.
  • FIG. 1 is a schematic diagram of the relationship between sensitivity and wavelength of a photodetector in the prior art.
  • FIG. 2 is a schematic diagram of distribution of PPG sensors in electronic equipment in another prior art.
  • FIG. 3 is a schematic structural diagram of an electronic device according to an embodiment of the present application.
  • FIG. 4 is a schematic diagram of distribution of a PPG sensor in an electronic device according to an embodiment of the present application.
  • FIG. 5 is a schematic cross-sectional view of the photodetector in FIG. 4 .
  • FIG. 6 is a schematic structural view of the photodiode in FIG. 5 mounted on a circuit substrate.
  • FIG. 7 is a schematic diagram of the arrangement of the first filter part and the second filter part in FIG. 5 .
  • FIG. 8 is a schematic diagram of the arrangement of the first filter part and the second filter part according to another embodiment of the present application.
  • FIG. 9 is a schematic diagram showing the relationship between sensitivity and wavelength of the photodetector in FIG. 4 .
  • the third light source 223 is the third light source 223
  • the first filter unit 243 The first filter unit 243
  • the pulse wave is the volume change waveform of the blood vessel produced when the heart sends blood.
  • the photoplethysmography (photo plethysmo graph, PPG) tracing method is to trace the corresponding PPG signal by measuring the attenuated light reflected and absorbed by the blood and tissues of the human body, and calculate the user's heart rate or blood oxygen saturation according to the PPG signal.
  • the method of physiological characteristic information such as degree.
  • a sensor that detects changes in the volume of blood vessels that occur when the heart pumps blood using the PPG tracing method is called a PPG sensor.
  • the PPG sensor can be applied to wrist wearable devices (such as smart watches and smart bracelets). After the user wears the smart watch, the PPG sensor surrounds the user's wrist and is located on the side of the watch body close to the user's skin to Detect the user's physiological characteristics. Physiological characteristics include, for example, heart rate and blood oxygen saturation.
  • the PPG sensor can also wrap around other body parts of the user (eg, ankles or fingers) for use in other wearable devices.
  • Other wearable devices are, for example, head-mounted devices (eg, smart helmets), clothing-type devices (eg, smart clothing, smart gloves, armbands), and the like.
  • tissue components when light is irradiated to human body parts such as wrists or fingers, various tissue components will absorb the light so that the light intensity after irradiation is weakened.
  • skin, muscle, bone, and vein are tissue components without pulsation, and the absorption of light is basically unchanged, such as the optical path remains unchanged; while arteries are pulsating, and their blood volume changes periodically with the beating of the heart.
  • the heart contracts, the heart ejects blood and the blood volume increases; when the heart relaxes, the heart returns blood and the blood volume decreases. Therefore, due to the change of blood volume, the absorption of light by the pulsating part of the artery will change, and the difference in light intensity, such as optical path deviation, will exist.
  • the photoplethysmography signal that is, the PPG signal
  • the user's biological information such as heart rate or blood oxygen saturation can be detected through the PPG signal.
  • the number of peaks within a certain period of time is obtained by filtering the original PPG signal, and the user's heart rate can be calculated according to the number of peaks.
  • SaO2 is blood oxygen saturation
  • HbO2 is oxyhemoglobin
  • Hb is hemoglobin.
  • the existing PPG method usually uses green light to measure heart rate, and uses red light and infrared light to measure blood oxygen saturation. That is to say, the existing PPG method uses different optical wavelengths for heart rate measurement and blood oxygen saturation measurement.
  • the detection of heart rate mainly uses green light, because the signal-to-noise ratio of PPG measured by green light is high, and the requirements for detection and signal conditioning are relatively low, even if there is some interference (such as motion), it is easier to eliminate.
  • the detection of blood oxygen saturation mainly uses red light and infrared light. This is because hemoglobin and oxyhemoglobin in the blood have different absorption rates for red light and infrared light. Oxyhemoglobin absorbs more near-infrared light (around 900nm), while Hemoglobin absorbs more red light (around 650nm), and this difference in absorption of red light and infrared light can be used to measure the value of blood oxygen saturation.
  • red light and near-infrared light can be used to detect the PPG signals of oxyhemoglobin and hemoglobin in the human body, and then the corresponding ratio between oxyhemoglobin and hemoglobin can be obtained through the PPG signal, so that the blood oxygen saturation of the human body can be obtained Spend.
  • the human body part is the wrist or finger
  • two beams with different peak wavelengths such as red light with a peak wavelength of 650nm and infrared light with a peak wavelength of 940nm, are used for detection.
  • the PPG sensor with the function of detecting heart rate and blood oxygen saturation usually includes a green light emitting diode (Light Emitting Diode, LED), a red light emitting LED, an infrared light emitting LED and a photodetector.
  • the photodetector is, for example, a photodiode (PD).
  • a photodetector (eg, PD) receiving attenuated light is a full-spectrum receiving device, which has a certain sensitivity to green light, red light and infrared light.
  • the infrared light in the 940nm band is the most sensitive, but the sensitivity to the green light in the 530nm band for heart rate detection is only about 50%, which greatly affects the sensing signal value of the green light.
  • the photodetector uses green light to measure the heart rate, it will also be interfered by the infrared signal emitted by the human body and the infrared signal of the external environment, which reduces the signal-to-noise ratio of the heart rate detection.
  • the photodetector uses red light and infrared light to measure blood oxygen saturation, it will also be interfered by the green light signal, which reduces the signal-to-noise ratio of blood oxygen saturation detection.
  • the PPG sensor uses two photodiodes (PD1 and PD2) with different sensitive wavelengths. Among them, PD1 is sensitive to red spectrum and infrared spectrum, and PD2 is sensitive to green spectrum.
  • this solution has the problem of low effective sensing area. For example, after green light, red light and infrared light are reflected and absorbed by human blood and tissue, the projection on the PPG sensor is shown as the dotted line in Figure 2.
  • the embodiments of the present application provide a photodetector, a PPG sensor using the photodetector, and an electronic device using the PPG sensor, so as to solve the problem of low signal-to-noise ratio existing in the existing PPG sensor.
  • FIG. 3 is a schematic structural diagram of an electronic device according to an embodiment of the present application.
  • the electronic device 100 is a smart watch, which includes a watch body 14 and a watch strap 12 connected to the watch body 14 .
  • a PPG sensor 20 Disposed in watch body 14 is a PPG sensor 20 (shown in FIG. 4 ).
  • the PPG sensor 20 surrounds the user's wrist and is located on the side of the watch body 14 close to the user's skin to detect the user's physiological characteristics.
  • “near” can be slightly separated or directly contacted.
  • Physiological characteristics include, for example, heart rate and blood oxygen saturation.
  • heart rate and blood oxygen saturation are taken as examples, those skilled in the art should understand that the embodiment of the present application can also be used to detect other biological information obtained through PPG signals, such as blood sugar or Blood pressure and other information are also within the protection scope of this application.
  • FIG. 4 is a schematic diagram of distribution of a PPG sensor in an electronic device according to an embodiment of the present application.
  • the PPG sensor 20 includes a plurality of light source groups 22 arranged at intervals and a plurality of photodetectors 24 arranged around the plurality of light source groups 22 .
  • Each light source group 22 includes a first light source 221 , a second light source 222 and a third light source 223 .
  • the outline of the PPG sensor 20 is substantially circular.
  • Two light source groups 22 are located in the middle area of the circle, and eight photodetectors 24 are arranged at equal intervals around the light source groups 22 .
  • the method of arranging a plurality of photodetectors 24 around the light source group 22 to detect the PPG signal can detect the light from different light source groups 22 to obtain PPG signals in multiple positions and directions, thereby avoiding the possibility of the user's biological tissue or Differences in wearing habits lead to inaccurate detection results; on the other hand, since PPG signals with better signal quality can be selected from PPG signals in multiple directions, the accuracy of user biometric information detection can be improved.
  • the contour shape of the PPG sensor 20 , the number of light source groups 22 , the number of photodetectors 24 , and the arrangement of the light source groups 22 and photodetectors 24 are not limited thereto.
  • the outline of the PPG sensor 20 can also be elliptical, long and so on.
  • the light source group 22 may include only one group, or more than two groups. There may be four photodetectors 24 respectively located on the four sides of the light source group 22 .
  • the first light source 221 , the second light source 222 , and the third light source 223 are respectively used to send out a first light signal, a second light signal, and a third light signal.
  • the light reflected by the first optical signal from the user's skin/tissue is at least partly in the first wavelength band
  • the light reflected by the second optical signal from the user's skin/tissue is at least partly in the second waveband
  • the third optical signal is transmitted by the user's skin/tissue.
  • the light reflected back by the tissue is at least partially in the third wavelength band.
  • the photodetector 24 is used to receive the light in the first waveband reflected by the user's skin/tissue from the first light signal and generate the first PPG signal, and receive the light in the second waveband reflected back by the user's blood and tissue from the second light signal. and generate the second PPG signal and receive the light in the third waveband reflected by the third light signal from the user's skin/tissue and generate the third PPG signal.
  • the first PPG signal, the second PPG signal and the third PPG signal are used to detect the physiological characteristics of the user.
  • the first PPG signal and the second PPG signal are used to detect the blood oxygen saturation of the user.
  • the first light signal is red light
  • the second light signal is infrared light.
  • the first light source 221 and the second light source 222 are respectively a light emitting diode (light emitting diode, LED) emitting red light and an LED emitting infrared light.
  • the third PPG signal is used to detect the user's heart rate.
  • the third light signal is green light
  • the third light source 223 is an LED that emits green light
  • the LED that emits red light, the LED that emits infrared light, and the LED that emits green light can be jointly arranged in a single package or a single die, They may also be respectively provided in separate packages or dies. That is, in a single package or die, one light source may be included, or more than two light sources emitting light of different colors may be included. Illustratively, in a single package or die, one red emitting LED, one green emitting LED and one infrared emitting LED are included.
  • a red-emitting LED can emit light with a peak wavelength of 650 nm
  • a green-emitting LED can emit light with a peak wavelength of 530 nm
  • an infrared-emitting LED can emit light with a peak wavelength of 940 nm. , but not limited to this.
  • the electronic device 100 further includes a processor (not shown) electrically connected to the PPG sensor 20 and a memory (not shown) storing instructions executable by the processor.
  • the processor may process the PPG signal generated by the PPG sensor 20 .
  • the processor detects the blood oxygen saturation of the user by processing the first PPG signal and the second PPG signal generated by at least one photodetector 24 (for example, determining the oxygenated hemoglobin and hemoglobin levels according to the first PPG signal and the second PPG signal) ratio, and then obtain the blood oxygen saturation of the user's target site).
  • the processor detects the user's heart rate by processing the third PPG signal generated by at least one photodetector 24 (eg, determines the user's heart rate to be detected according to the number of peaks in the third PPG signal).
  • the processor can also process instructions executed in the electronic device 100, and the instructions include instructions stored in the memory or instructions input from an external input/output device.
  • the memory can be used to store non-transitory software programs, non-transitory computer-executable programs and modules.
  • the processor performs various functional applications and data processing by executing non-transitory software programs, instructions and modules stored in the memory.
  • FIG. 5 is a schematic cross-sectional view of the photodetector in FIG. 4 .
  • the photodetector 24 includes a circuit substrate 241 , a photodiode 242 on the circuit substrate 241 , a first filter 243 and a second filter 244 on the photodiode 242 , and an encapsulation layer 246 .
  • the first filter part 243 and the second filter part 244 are located on a side of the photodiode 242 away from the circuit substrate 241 .
  • the photodiode 242 is electrically connected to the circuit substrate 241 through a wire 245 .
  • the encapsulation layer 246 covers the photodiode 242 , the first filter part 243 , the second filter part 244 and the leads 245 .
  • the circuit substrate 241 is, for example, a printed circuit board
  • the lead wires 245 are, for example, gold wires
  • the material of the packaging layer 246 is, for example, epoxy resin, but not limited thereto.
  • FIG. 6 is a schematic structural view of the photodiode in FIG. 5 mounted on a circuit substrate. As shown in FIG. 6 , the photodiode 242 is electrically connected to the circuit substrate 241 through a wire 245 . The light receiving surface of the photodiode 242 is substantially rectangular.
  • FIG. 7 is a schematic diagram of the arrangement of the first filter part and the second filter part in FIG. 5 .
  • the plurality of first filter portions 243 and the plurality of second filter portions 244 are arranged in a matrix in multiple rows and columns. Among them, in multiple rows and multiple columns, each row is arranged with a first filter part 243 and a second filter part 244 alternately and periodically, and each column is a first filter part 243 and a second filter part 244 are arranged alternately and periodically.
  • the projection of the first filter part 243 on the photodiode 242 is a rectangle
  • the projection of the second filter part 244 on the photodiode 242 is a rectangle.
  • the first filter part 243 and the second filter part 244 are equal in size. In other embodiments, the shapes and arrangement rules of the first filter part 243 and the second filter part 244 are not limited thereto.
  • the photodiode 242 is used to sense the light of the first wavelength band, the second wavelength band and the third wavelength band.
  • the first filter part 243 is used for selectively passing the light of the first wavelength band and the second wavelength band, and selectively blocking the light of the third wavelength band.
  • the second filter part 244 is used to selectively transmit the light of the third wavelength band, and selectively block the light of the first and second wavelength bands.
  • the first waveband is within the red spectrum (620nm-780nm)
  • the second waveband is within the infrared spectrum (780nm-1mm)
  • the third waveband is within the green light spectrum (490nm-560nm). That is, red light, infrared light and green light can all be sensed by the photodiode 242 .
  • the first filter part 243 can selectively transmit red light and infrared light and block green light.
  • the second filter part 244 can selectively transmit green light and block red light and infrared light.
  • the area covered by the first filter part 243 of the photodiode 242 can receive red light and infrared light, but not green light; the area covered by the second filter part 244 of the photodiode 242 can receive green light, but not Red and infrared light.
  • the first filter part 243 can selectively transmit the red light and infrared light, and the second filter part 244 can selectively block the red light and infrared light. Therefore, the area of the photodiode 242 covered by the first filter portion 243 is the most sensitive area for sensing red light and infrared light. When red light and infrared light are used to test blood oxygen saturation, the area of the photodetector 24 provided with the first filter part 243 is the area that mainly senses red light and infrared light.
  • the second filter part 244 can selectively transmit the green light, and the first filter part 243 can selectively block the green light. Therefore, the area of the photodiode 242 covered by the second filter portion 244 is the most sensitive area for sensing green light. When the heart rate test is performed with green light, the area of the photodetector 24 provided with the second filter portion 244 is the area that mainly senses the green light.
  • the photodetector when the heart rate test is performed by using the LED that emits green light, the photodetector mainly uses the area provided with the second filter part (that is, the area most sensitive to green light) to sense ; while utilizing red-lighting LEDs and infrared-light LEDs to carry out blood oxygen saturation tests, the photodetector mainly utilizes the area provided with the first filter (that is, the most sensitive area to red light and infrared light) for sensing. In this way, the measurement of the heart rate by the photodetector is relatively decoupled from the measurement of the blood oxygen saturation, which can achieve a high signal-to-noise ratio and improve measurement accuracy.
  • the PPG sensor 20 uses red-light emitting LEDs and infrared-emitting LEDs to measure blood oxygen saturation, the red light and infrared light are reflected and absorbed by the blood and tissues of the human body to form attenuated light, and the attenuated light
  • the light transmitted through the first filter unit 243 is received by the photodiode 242 .
  • the photodiode 242 converts the received attenuated light into an electrical signal.
  • the electrical signal is subjected to signal processing such as amplification and filtering to obtain a first PPG signal and a second PPG signal.
  • the processor can determine the ratio of oxyhemoglobin to hemoglobin according to the first PPG signal and the second PPG signal, and then calculate the blood oxygen saturation of the user's target site. Because when red light and infrared light are used to measure blood oxygen saturation, green light will be blocked by the first filter part 243 . Therefore, the noise during blood oxygen saturation detection can be reduced, thereby improving the signal-to-noise ratio of blood oxygen saturation detection.
  • the PPG sensor 20 uses green LEDs to perform heart rate tests, the green light is reflected and absorbed by the blood and tissues of the human body to form attenuated light, which passes through the second filter part 244 and is received by the photodiode 242. take over.
  • the photodiode 242 converts the received attenuated light into an electrical signal.
  • the electrical signal is subjected to signal processing such as amplification and filtering to obtain a third PPG signal.
  • the processor determines the heart rate of the user to be detected according to the third PPG signal. Because the infrared signal emitted by part of the human body and the infrared signal of the external environment are blocked by the second filter part 244 when using the green light to detect the heart rate. Therefore, the noise of the heart rate detection can be reduced, thereby improving the signal-to-noise ratio of the heart rate detection.
  • the first filter part 243 and the second filter part 244 can be formed in a specific area of the photodiode 242 by coating.
  • the first filter part 243 can block the green light through absorption or reflection.
  • the second filter part 244 can block red light and infrared light through absorption or reflection.
  • the photodiode 242 is a full spectrum sensitive photodiode, but the photodiode 242 is not as sensitive to red and infrared light as the photodiode 242 is to green light.
  • the ratio of the sensitivity of the photodiode 242 to red light and infrared light to the sensitivity of the photodiode 242 to green light is roughly (1.6 ⁇ 1.3):1.
  • the photogenerated current ratio generated is (1.6-1.3):1.
  • the total area of the projection of all the first filter parts 243 on the photodiode 242 is the same as the projection of all the second filter parts 244 on the photodiode 242
  • the ratio of the total area is 1: (1.6 ⁇ 1.3), so that the photoelectric current generated by the photodetector 24 receiving 1mW/cm2 light radiation illuminance and infrared light irradiation and the photodetector 24 receiving 1mW/cm2 light
  • the photogenerated current generated by the green light irradiation of the irradiance is roughly equivalent.
  • the sensitivity of the photodetector 24 to the green light of about 520 nm is approximately equal to the sensitivity of the photodetector 24 to the infrared light of about 860 nm.
  • the ratio of the total area of projections of all second filter parts 244 on the photodiodes 242 to the total area of projections of all first filter parts 243 on the photodiodes 242 is, for example, (1.6: 1), (1.5:1), (1.4:1), (1.3:1), etc. Wherein, when the ratio is 1.5:1, the sensitivity of the photodetector to the green light around 520nm is the closest to the sensitivity to the infrared light around 860nm.
  • the total area of the projection of the first filter portion 243 on the photodiode 242 smaller than the total area of the projection of the second filter portion 244 on the photodiode 242, when the PPG sensor 20 uses green light
  • the LED performs a heart rate test, even if the infrared signal emitted by part of the human body and the infrared signal of the external environment are incident on the first filter part 243 and sensed by the photodiode 242, because all the first filter parts 243 are on the photodiode 242
  • the total area of the projection is smaller than the total area of projections of all the second filter parts 244 on the photodiode 242.
  • the photodiode 242 After the photodiode 242 receives the infrared signal emitted by the human body and the infrared signal of the external environment, it emits the infrared signal corresponding to the human body.
  • the infrared signal of the infrared signal and the infrared signal of the external environment can generate a small photocurrent, so that the noise of the heart rate detection can be reduced, thereby improving the signal-to-noise ratio of the heart rate detection.
  • the projected area of each first filter part 243 on the photodiode 242 is the same as the projected area of each second filter part 244 on the photodiode 242, by adjusting the first filter part 243 and the ratio of the number of the second filter parts 244, so that the total area of the projections of all the first filter parts 243 on the photodiodes 242 and the total area of the projections of all the second filter parts 244 on the photodiodes 242
  • the area ratio is 1:(1.6 ⁇ 1.3).
  • the number of the first filter part 243 and the number of the second filter part 244 are the same, and the area of the projection of each first filter part 243 on the photodiode 242 can be adjusted by adjusting the area of the projection of each first filter part 243 on the photodiode 242
  • the ratio of the projected area of the portion 244 on the photodiode 242 makes the total area of the projection of all the first filter portions 243 on the photodiode 242 and the ratio of the projection of all the second filter portions 244 on the photodiode 242
  • the ratio of the total area is 1: (1.6 ⁇ 1.3).
  • a plurality of first filter parts 243 and a plurality of second filter parts 244 are arranged in a matrix in multiple rows and multiple columns. Among them, in multiple rows and multiple columns, each row is arranged with a first filter part 243 and a second filter part 244 alternately and periodically, and each column is a first filter part 243 and a second filter part 244 are arranged alternately and periodically.
  • the number of the first filter part 243 and the number of the second filter part 244 are the same.
  • the projection of the first filter part 243 on the photodiode 242 and the projection of the second filter part 244 on the photodiode 242 are rectangular, and the width of the first filter part 243 is the same as the width of the second filter part 244 . Therefore, by adjusting the ratio of the length of the first filter part 243 to the length of the second filter part 244 to be 1: (1.6-1.3), the projection of all the first filter parts 243 on the photodiode 242 The ratio of the total area to the total area of the projections of all the second filter parts 244 on the photodiode 242 is 1:(1.6 ⁇ 1.3).
  • the shapes and arrangement rules of the first filter part 243 and the second filter part 244 are not limited thereto.
  • the number of the first filter part 243 and the second filter part 244 is different, and the area of each first filter part 243 and the area of the second filter part 244 are also different, but all the first filter parts 243
  • the ratio of the total area of the projections on the photodiode 242 to the total area of the projections of all the second filters 244 on the photodiode 242 is 1:(1.6 ⁇ 1.3).
  • the photodiode is sensitive to multiple bands (red light band, green light band, and infrared light band).
  • the light part selectively transmits green light.
  • the measurement of the heart rate and the measurement of the blood oxygen saturation by the photodetector are relatively decoupled, and can Achieve high signal-to-noise ratio and improve measurement accuracy.
  • the PPG sensor of the embodiment of the present application can effectively sense heart rate when using green light and blood oxygen saturation using red light and infrared. The measurement area is larger and the signal-to-noise ratio is higher.
  • the total area of the projection of the first filter part on the photodiode is the same as the total area of the projection of all the second filter parts on the photodiode.
  • the ratio of the projected total areas can vary.
  • a processor of the electronic device may process the PPG signal generated by the one or more photodetectors.
  • the total area of all first filter parts is greater than or equal to the total area of all second filter parts, this part of photodetectors (for convenience of description, define this part of photodetectors as the first A photodetector) is more sensitive to red light and infrared light than to green light; and in other photodetectors, the total area of all the first filter parts is smaller than that of all the second filter parts
  • the total area of the other photodetectors (for the convenience of description, define the other photodetectors as the second photodetectors) is more sensitive to green light than to red light and infrared light.
  • the processor of the electronic device can choose to turn on the first photodetector that is more sensitive to red light and infrared light, and turn off the second photodetector, By using the first photodetector which is more sensitive to red light and infrared light, the accuracy of blood oxygen saturation measurement is improved.
  • the processor of the electronic device can choose to turn on the second photodetector that is more sensitive to heart rate sensing, and turn off the first photodetector. The second photodetector improves the accuracy of heart rate measurement.
  • the processor of the electronic device can also turn on the first photodetector and the second photodetector at the same time, by multiple first photodetectors
  • the heart rate (or blood oxygen saturation) is measured by performing processing and calculation with the PPG signals generated by the plurality of second photodetectors.
  • the PPG sensor is not limited to being applied to smart watches, for example, the PPG sensor can also be applied to a smart bracelet; or, the PPG sensor can also surround other body parts of the user (such as the head, ankle or finger), used in other wearable devices.
  • Other wearable devices are, for example, head-mounted devices (eg, smart helmets), clothing-type devices (eg, smart clothing, smart gloves, armbands), and the like.
  • the PPG sensor may be attached or integrated into a user's shoe, sock, tie, sleeve or collar of a shirt, waistband of pants or skirt, and the like. Further, the PPG sensor can also be detached from the user's shoes or clothing. For example, when using the PPG sensor to detect the user's physiological characteristics, the PPG sensor can be attached to the user's shoes or clothing, and after the detection is completed, the PPG sensor can be detached from the user's shoes or clothing. In this way, the location where the PPG sensor needs to be attached can be selected for different users and/or for different body parts of the same user, making the application scenarios of the PPG sensor diverse and flexible.
  • the PPG sensor can also be applied to devices with a health detection function, such as blood oxygen meters, heart rate detectors, etc., but not limited thereto.

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Abstract

光电探测器（24）、PPG传感器（20）及电子设备（100），旨在解决现有的感测用户生理特征的PPG传感器存在信噪比低的问题。其中，光电探测器（24）包括光电二极管（242），用于感测第一波段、第二波段和第三波段的光；至少一个第一滤光部（243），位于光电二极管（242）上，用于透过第一波段和第二波段的光，并阻挡第三波段的光；以及至少一个第二滤光部（244），位于光电二极管（242）上，用于透过第三波段的光，并阻挡第一波段和第二波段的光。

Description

光电探测器、PPG传感器及电子设备
相关申请的交叉引用
本申请要求在2021-12-07提交中国专利局、申请号为202111485328.3、申请名称为“光电探测器、PPG传感器及电子设备”的中国专利的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及生物感测领域，具体而言，涉及光电探测器、光电容积脉搏波描记(photo plethysmo graph，PPG)传感器及电子设备。
背景技术
现有的应用于电子设备中以感测用户生理特征的PPG传感器，存在信噪比低的问题。
发明内容
本申请第一方面提供一种光电探测器，其包括：
光电二极管，用于感测第一波段、第二波段和第三波段的光；
至少一个第一滤光部，位于光电二极管上，用于透过第一波段和第二波段的光，并阻挡第三波段的光；以及
至少一个第二滤光部，位于光电二极管上，用于透过第三波段的光，并阻挡第一波段和第二波段的光。
该光电探测器，通过设置第一滤光部和第二滤光部，可使光电二极管对第一波段和第二波段的光的检测与对第三波段的光的检测相对解耦。即，光电探测器可利用光电二极管设置有第一滤光部的区域，检测第一波段和第二波段的光；利用光电二极管设置有第二滤光部的区域，检测第三波段的光。此外，在光电探测器检测第一波段和第二波段的光时，由于第三波段的光会被第一滤光部阻挡而无法入射到光电二极管，因此，可避免第三波段的光的影响，降低检测第一波段和第二波段的光的噪声，进而提高检测第一波段和第二波段的光的信噪比。同理，在光电探测器检测第三波段的光时，由于第一波段和第二波段的光会被第二滤光部阻挡而无法入射到光电二极管，因此，可避免第一波段和第二波段的光的影响，降低检测第三波段的光的噪声，进而提高检测第三波段的光的信噪比。
在一些实施例中，第一波段在红光光谱之内，第二波段在红外光谱之内，第三波段在绿光光谱之内。即，红光、红外光和绿光均能被光电二极管感测。第一滤光部可选择性地透过红光和红外光并阻挡绿光。第二滤光部可选择性地透过绿光并阻挡红光和红外光。因此，光电二极管被第一滤光部覆盖的区域可接收红光和红外光，但不接收绿光；光电二极管被第二滤光部覆盖的区域可接收绿光，但不接收红光和红外光。
在一些实施例中，沿光电二极管的厚度方向上，所述至少一个第一滤光部在光电二极管上的投影的面积与所述至少一个第二滤光部在光电二极管上的投影的面积之比为1： (1.6～1.3)。光电二极管为全光谱敏感的光电二极管，该光电二极管对红光和红外光的敏感性和该光电二极管对绿光的敏感性不同。具体地，该光电二极管对红光和红外光的敏感性和该光电二极管对绿光的敏感性比例大致为(1.6～1.3)：1。也就是说，同一颗光电二极管接收1mW/cm2光辐射照度的红光及红外光，和绿光照射，产生的光生电流比为(1.6～1.3)：1。因此，一些实施例中，所有的第一滤光部在光电二极管上的投影的总面积与所有的第二滤光部在光电二极管上的投影的总面积之比为1：(1.6～1.3)，以使得光电探测器对收1mW/cm2光辐射照度的红光及红外光照射产生的光生电流与光电探测器对收1mW/cm2光辐射照度的绿光照射产生的光生电流大致相当。
在一些实施例中，第一滤光部与第二滤光部的数量相同，沿光电二极管的厚度方向上，每一第一滤光部在光电二极管上的投影的面积与每一第二滤光部在光电二极管上的投影的面积之比为1：(1.6～1.3)。在另一些实施例中，沿光电二极管的厚度方向上，每一第一滤光部在光电二极管上的投影的面积与每一第二滤光部在光电二极管上的投影的面积相同，第一滤光部与第二滤光部的数量之比为1：(1.6～1.3)。即，可通过调整第一滤光部与第二滤光部的数量、或者每一个第一滤光部与第二滤光部的面积的大小，来调整所有的第一滤光部的总面积与所有的第二滤光部的总面积之比。
在一些实施例中，多个第一滤光部和多个第二滤光部呈矩阵排布为多行多列；多行多列中，每一行为一个第一滤光部和一个第二滤光部交替周期性重复排布，每一列为一个第一滤光部和一个第二滤光部交替周期性重复排布。
在一些实施例中，沿光电二极管的厚度方向上，第一滤光部在光电二极管上的投影为矩形，第二滤光部在光电二极管上的投影为矩形。在其他实施例中，第一滤光部和第二滤光部的形状及排布规则不限于此。
在一些实施例中，第一滤光部与第二滤光部的数量相同，沿光电二极管的厚度方向上，第一滤光部在光电二极管上的投影所形成的矩形的宽度与第二滤光部在光电二极管上的投影所形成的矩形的宽度相同，第一滤光部在光电二极管上的投影所形成的矩形的长度与第二滤光部在光电二极管上的投影所形成的矩形的长度之比为1：(1.6～1.3)。
在一些实施例中，光电探测器还包括电路基板，光电二极管电性连接电路基板。电路基板例如为印刷电路板，光电二极管通过引线电性连接电路基板，引线例如为金线，但不限于此。
在一些实施例中，光电探测器还包括封装层，封装层包覆光电二极管、第一滤光部及第二滤光部。封装层的材料例如为环氧树脂，但不限于此。
本申请第二方面提供一种PPG传感器，其包括：
第一方面的光电探测器；
第一光源，用于发出第一光信号，第一光信号经用户的皮肤/组织反射的光至少部分位于第一波段；
第二光源，用于发出第二光信号，第二光信号经用户的皮肤/组织反射回的光至少部分位于第二波段；以及
第三光源，用于发出第三光信号，第三光信号经用户的皮肤/组织反射回的光至少部分位于第三波段；
其中，光电探测器用于接收第一波段的光并生成第一PPG信号、接收第二波段的光并生成第二PPG信号以及接收第三波段的光并生成第三PPG信号，第一PPG信号、第二PPG信 号和第三PPG信号用于检测用户的生理特征。
该PPG传感器包括第一方面的光电探测器，由于光电探测器设置有第一滤光部和第二滤光部，可使光电二极管对第一波段和第二波段的光的检测与对第三波段的光的检测相对解耦。即，光电探测器可利用光电二极管设置有第一滤光部的区域，检测第一波段和第二波段的光；利用光电二极管设置有第二滤光部的区域，检测第三波段的光。此外，在光电探测器检测第一波段和第二波段的光时，由于第三波段的光会被第一滤光部阻挡而无法入射到光电二极管，因此，可避免第三波段的光的影响，降低检测第一波段和第二波段的光的噪声，进而提高检测第一波段和第二波段的光的信噪比，使得第一PPG信号和第二PPG信号的检测更准确。同理，在光电探测器检测第三波段的光时，由于第一波段和第二波段的光会被第二滤光部阻挡而无法入射到光电二极管，因此，可避免第一波段和第二波段的光的影响，降低检测第三波段的光的噪声，进而提高检测第三波段的光的信噪比，使得第三PPG信号的检测更准确。如此，根据第一PPG信号、第二PPG信号和第三PPG信号检测的用户的生理特征的数据更准确。
在一些实施例中，PPG传感器包括光源组，光源组包括第一光源、第二光源和第三光源，多个光电探测器环绕光源组间隔设置。将多个光电探测器环绕光源组设置来检测PPG信号的方式，一方面，能够得到多个位置方向上的PPG信号，从而能够避免用户生物组织或佩戴习惯差异导致检测结果不准确的问题；另一方面，由于能够从多个位置方向上的PPG信号中选取信号质量较好的PPG信号，从而能够提高用户生物信息检测的准确性。
在一些实施例中，PPG传感器包括间隔设置的多个光源组。多个光源组的设置，使得光电探测器能够检测来自不同光源组的光，从而能够避免用户生物组织或佩戴习惯差异导致检测结果不准确的问题，从而能够提高用户生物信息检测的准确性。
在一些实施例中，生理特征包括血氧饱和度和心率，第一光信号为红光，第二光信号为红外光，第一PPG信号和第二PPG信号用于检测用户的血氧饱和度，第三光信号为绿光，第三PPG信号用于检测用户的心率。其中，心率的检测主要利用绿光，是因为绿光测到的PPG信噪比高，对于检测及信号调理的要求比较低，即便有一些干扰(例如运动)也比较容易剔除。而血氧饱和度的检测主要利用红光和红外光，是原因血液中血红蛋白和氧合血红蛋白对红光与红外光的吸收率不同，氧合血红蛋白吸收近红外光(900nm左右)较多，而血红蛋白吸收红光(650nm左右)较多，利用这种对红光、红外光吸收的差异性就可以测量出血氧饱和度的值。因此，可以利用红光和接近红外光的光分别检测人体部位的氧合血红蛋白和血红蛋白的PPG信号，然后通过PPG信号得到氧合血红蛋白和血红蛋白相应的比值，这样就得到了人体部位的血氧饱和度。
本申请第三方面提供一种电子设备，其包括第二方面的PPG传感器。电子设备可以为腕式可穿戴设备(如，智能手表、智能手环)、头戴式设备(如，智能头盔)、服装型设备(如，智能服装、智能手套、臂带)等。电子设备也可以为具有健康检测功能的设备，如血氧测量仪、心率检测仪等。
附图说明
图1为一现有技术中光电探测器的灵敏度和波长的关系示意图。
图2为另一现有技术中PPG传感器在电子设备中的分布示意图。
图3为本申请一实施例的电子设备的结构示意图。
图4为本申请一实施例的PPG传感器在电子设备中的分布示意图。
图5为图4中光电探测器的剖面示意图。
图6为图5中光电二极管安装至电路基板上的结构示意图。
图7为图5中第一滤光部和第二滤光部的排布示意图。
图8为本申请另一实施例的第一滤光部和第二滤光部的排布示意图。
图9为图4中光电探测器的灵敏度和波长的关系示意图。
主要元件符号说明：
电子设备                          100
表带                              12
表体                              14
PPG传感器                         20
光源组                            22
第一光源                          221
第二光源                          222
第三光源                          223
光电探测器                        24
电路基板                          241
光电二极管                        242
第一滤光部                        243
第二滤光部                        244
引线                              245
封装层                            246
具体实施方式
脉搏波是心脏发送血液时产生的血管的体积变化波形。光电容积脉搏波(photo plethysmo graph，PPG)描记法是通过测量经过人体血液和组织反射、吸收后的衰减光，描记出对应的PPG信号，并根据PPG信号计算出用户的例如心率或血氧饱和度等生理特征信息的方法。利用PPG描记法检测心脏发送血液时产生的血管的体积变化的传感器称为PPG传感器。
PPG传感器可应用于腕式可穿戴设备(如，智能手表、智能手环)中，用户佩戴该智能手表后，PPG传感器环绕用户的手腕，并位于手表的表体靠近用户皮肤的一侧，以检测用户的生理特征。生理特征例如包括心率和血氧饱和度。PPG传感器也可环绕用户的其他身体部位(如，脚踝或手指)，以应用于其他的可穿戴装置中。其他的可穿戴装置例如，为头戴式设备(如，智能头盔)、服装型设备(如，智能服装、智能手套、臂带)等。
具体地，当光照射到人体部位例如手腕或手指时，各种组织成分都会吸收光使得照射后的光强减弱。其中，皮肤、肌肉、骨骼、静脉是没有搏动的组织成分，对光的吸收基本是不变的例如光程保持不变；而动脉是存在搏动的，其血容积随着心脏的搏动而周期性地发生变化，当心脏收缩时，心脏射血，血液容积增大；而当心脏舒张时，心脏回 血，血液容积减小。因此，由于有血液容积变化，动脉搏动部分对光的吸收会所变化，光强的大小不同例如存在光程偏差。正是由于动脉对光的吸收有变化而其他组织对光的吸收基本不变，因此，当光束照射到人体部位例如手腕或手指时，反射光跟随动脉搏动而发生周期性的强弱变化，可以得到光电容积脉搏波信号即PPG信号，通过PPG信号能够检测用户的生物信息例如心率或血氧饱和度等。
以心率为例，通过对原始的PPG信号进行滤波处理，得到一定时间内的波峰个数，根据波峰个数就能够算出用户的心率值。
以血氧饱和度为例，血氧饱和度是指人体血液中氧合血红蛋白HbO2占全部可结合的血红蛋白(Hb)的百分比，即血液中血氧的浓度，可以通过公式SaO2＝HbO2/(HbO2+Hb)确定血氧饱和度。其中，SaO2为血氧饱和度，HbO2为氧合血红蛋白，Hb为血红蛋白。
另外，现有的PPG法通常采用绿光测量心率，采用红光与红外光测量血氧饱和度。也就是说，现有的PPG法测量心率和测量血氧饱和度所使用的光学波长是不同的。
具体地，心率的检测主要利用绿光，是因为绿光测到的PPG信噪比高，对于检测及信号调理的要求比较低，即便有一些干扰(例如运动)也比较容易剔除。而血氧饱和度的检测主要利用红光和红外光，是原因血液中血红蛋白和氧合血红蛋白对红光与红外光的吸收率不同，氧合血红蛋白吸收近红外光(900nm左右)较多，而血红蛋白吸收红光(650nm左右)较多，利用这种对红光、红外光吸收的差异性就可以测量出血氧饱和度的值。因此，可以利用红光和接近红外光的光分别检测人体部位的氧合血红蛋白和血红蛋白的PPG信号，然后通过PPG信号得到氧合血红蛋白和血红蛋白相应的比值，这样就得到了人体部位的血氧饱和度。举例而言，设人体部位为手腕或手指部位，使用两种不同峰值波长的光束如峰值波长为650nm的红光以及峰值波长为940nm的红外光进行检测，当红光、红外光穿过手腕或手指时，由于两种光的氧合血红蛋白和血红蛋白的吸收不同，得到对应的氧合血红蛋白和血红蛋白的PPG信号，通过PPG信号得到氧合血红蛋白和血红蛋白相应的比值，根据该比值得到手腕或手指的血氧饱和度。
因此，兼具检测心率和血氧饱和度功能的PPG传感器通常包括发绿光的发光二极管(Light Emitting Diode，LED)、发红光的LED、发红外光的LED和光电探测器。光电探测器例如为光电二极管(photo diode，PD)。
以下结合图1和图2说明现有的PPG传感器主要存在的问题。
如图1所示，在现有技术中，接收衰减光的光电探测器(如，PD)为全光谱接收的器件，其对绿光、红光及红外光均具有一定的灵敏度。其中，对940nm波段的红外光最灵敏，但是对检测心率功能的530nm波段的绿光灵敏度只有50％左右，极大的影响了对绿光的感应信号值。而且，光电探测器在使用绿光进行心率测量时，还会受到人体发射出来的红外信号和外界环境红外信号的干扰，降低了心率检测的信噪比。此外，光电探测器在使用红光和红外光进行血氧饱和度测量时，还会受到绿光信号的干扰，降低了血氧饱和度检测的信噪比。
[根据细则91更正 09.01.2022]
如图2所示，另一现有技术中，PPG传感器采用两种不同敏感波长的光电二极管(PD1和PD2)。其中，PD1对红光谱段和红外光谱段敏感，PD2对绿光谱段敏感。然而，该种方案存在有效感测面积低的问题。例如，绿光、红光和红外光经过人体血液和组织反射、吸收后，在PPG传感器上的投影为图2中的虚线所示。其中，在使用绿光进行心率测量，只有被虚线所覆盖的PD2用于检测，而被虚线所覆盖的两个PD1不能感测绿光， 导致PPG传感器获得的绿光的感应信号值较弱，降低了心率检测的信噪比。同样，在使用红光和红外光进行血氧饱和度测量时，只有被虚线所覆盖的两个PD1用于检测，而被虚线所覆盖的PD2不能感测红光和红外光，导致PPG传感器获得的红光和红外光的感应信号值较弱，降低了血氧饱和度检测的信噪比。
为此，本申请实施例中提供一种光电探测器、应用该光电探测器的PPG传感器及应用该PPG传感器的电子设备，以解决现有的PPG传感器存在的信噪比低的问题。
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅是本申请一部分实施例，而不是全部的实施例。
图3为本申请一实施例的电子设备的结构示意图。图3中，电子设备100为智能手表，其包括表体14和连接表体14的表带12。表体14中设置有PPG传感器20(示出在图4中)。用户佩戴该智能手表后，PPG传感器20环绕用户的手腕，并位于表体14靠近用户皮肤的一侧，以检测用户的生理特征。其中，“靠近”可以为略微分开或者直接接触。生理特征例如包括心率和血氧饱和度。
需要说明的是，虽然以心率和血氧饱和度为例进行了说明，但是本领域普通技术人员应该理解的是，本申请实施例还能够用于检测其他通过PPG信号得到的生物信息例如血糖或血压等信息，这同样在本申请的保护范围内。
图4为本申请一实施例的PPG传感器在电子设备中的分布示意图。如图4所示，PPG传感器20包括间隔设置的多个光源组22以及环绕该多个光源组22设置的多个光电探测器24。每一光源组22包括一个第一光源221、一个第二光源222和一个第三光源223。图4中，PPG传感器20的轮廓大致呈圆形。两个光源组22位于圆形的中间区域，八个光电探测器24环绕光源组22等间距地间隔设置。
将多个光电探测器24环绕光源组22设置来检测PPG信号的方式，一方面，能够检测来自不同光源组22的光，以得到多个位置方向上的PPG信号，从而能够避免用户生物组织或佩戴习惯差异导致检测结果不准确的问题；另一方面，由于能够从多个位置方向上的PPG信号中选取信号质量较好的PPG信号，从而能够提高用户生物信息检测的准确性。
其他实施例中，PPG传感器20的轮廓形状、光源组22的数量、光电探测器24的数量、及光源组22和光电探测器24的排布不限于此。例如，PPG传感器20的轮廓还可以为椭圆形、长条形等。光源组22可只包括一组，或多于两组。光电探测器24可以为分别位于光源组22的上下左右四侧的四个。
具体地，第一光源221、第二光源222、第三光源223分别用于发出第一光信号、第二光信号、第三光信号。第一光信号经用户的皮肤/组织反射的光至少部分位于第一波段，第二光信号经用户的皮肤/组织反射回的光至少部分位于第二波段，第三光信号经用户的皮肤/组织反射回的光至少部分位于第三波段。光电探测器24用于接收第一光信号经用户的皮肤/组织反射的位于第一波段的光并生成第一PPG信号、接收第二光信号经用户的血液和组织反射回的位于第二波段的光并生成第二PPG信号以及接收第三光信号经用户的皮肤/组织反射回的位于第三波段的光并生成第三PPG信号。第一PPG信号、第二PPG信号和第三PPG信号用于检测用户的生理特征。
在一些实施例中，第一PPG信号和第二PPG信号用于检测用户的血氧饱和度。第一光信号为红光，第二光信号为红外光。第一光源221、第二光源222分别为发红光的发 光二极管(light emitting diode，LED)、发红外光的LED。第三PPG信号用于检测用户的心率。第三光信号为绿光，第三光源223为发绿光的LED，其中，发红光的LED、发红外光的LED及发绿光的LED可以共同设置在单个封装或单个管芯中，也可以分别设置在分开的封装或管芯中。即，在单个封装或管芯中，可以包括一个光源，也可以包括两个以上发不同颜色光的光源。示例性地，在单个封装或管芯中，包括一个发红光的LED、一个发绿光的LED和一个发红外光的LED。
在一些实施例中，发红光的LED可以发射具有650nm的峰值波长的光，发绿光的LED可以发射具有530nm的峰值波长的光，发红外光的LED可以发射具有940nm的峰值波长的光，但不限于此。
可以理解，电子设备100还包括与PPG传感器20电性连接的处理器(图未示)以及存储有可由处理器执行的指令的存储器(图未示)。处理器可以对PPG传感器20生成的PPG信号进行处理。例如处理器通过处理至少一个光电探测器24生成的第一PPG信号和第二PPG信号以检测用户的血氧饱和度(例如，根据第一PPG信号和第二PPG信号确定氧合血红蛋白和血红蛋白的比值，进而得到用户的目标部位的血氧饱和度)。或，处理器通过处理至少一个光电探测器24生成的第三PPG信号检测用户的心率(例如，根据第三PPG信号中的波峰的个数确定待检测用户的心率)。此外，处理器还可以对在电子设备100内执行的指令进行处理，指令包括存储在存储器中的指令或外部输入/输出装置上输入的指令。存储器作为一种非暂时计算机可读存储介质，可用于存储非暂时软件程序、非暂时计算机可执行程序以及模块。处理器通过运行存储在存储器中的非暂时软件程序、指令以及模块，从而执行各种功能应用以及数据处理。
图5为图4中光电探测器的剖面示意图。如图5所示，光电探测器24包括电路基板241、位于电路基板241上的光电二极管242、位于光电二极管242上的第一滤光部243和第二滤光部244以及封装层246。第一滤光部243和第二滤光部244位于光电二极管242远离电路基板241的一侧。光电二极管242通过引线245电性连接电路基板241。封装层246包覆光电二极管242、第一滤光部243、第二滤光部244和引线245。电路基板241例如为印刷电路板，引线245例如为金线，封装层246的材料例如为环氧树脂，但不限于此。
图6为图5中光电二极管安装至电路基板上的结构示意图。如图6所示，光电二极管242通过引线245电性连接电路基板241。光电二极管242的光接收面大致呈矩形。
图7为图5中第一滤光部和第二滤光部的排布示意图。如图7所示，多个第一滤光部243和多个第二滤光部244呈矩阵排布为多行多列。其中，多行多列中，每一行为一个第一滤光部243和一个第二滤光部244交替周期性重复排布，每一列为一个第一滤光部243和一个第二滤光部244交替周期性重复排布。沿光电二极管242的厚度方向上，第一滤光部243在光电二极管242上的投影为矩形，第二滤光部244在光电二极管242上的投影为矩形。第一滤光部243和第二滤光部244等大。在其他实施例中，第一滤光部243和第二滤光部244的形状及排布规则不限于此。
光电二极管242用于感测第一波段、第二波段和第三波段的光。第一滤光部243用于选择性地透过第一波段、第二波段的光，并选择性地阻挡第三波段的光。第二滤光部244用于选择性地透过第三波段的光，并选择性地阻挡第一波段、第二波段的光。
一些实施例中，第一波段在红光光谱(620nm～780nm)之内，第二波段在红外光谱(780nm～1mm)之内，第三波段在绿光光谱(490nm～560nm)之内。即，红光、红外光和绿光均能被光电二极管242感测。其中，第一滤光部243可选择性地透过红光和红外光并阻挡绿光。第二滤光部244可选择性地透过绿光并阻挡红光和红外光。因此，光电二极管242被第一滤光部243覆盖的区域可接收红光和红外光，但不接收绿光；光电二极管242被第二滤光部244覆盖的区域可接收绿光，但不接收红光和红外光。
当红光和红外光照射到光电探测器24时，第一滤光部243可选择性地使红光和红外光透过，第二滤光部244可选择性地阻挡红光和红外光。因此，光电二极管242被第一滤光部243覆盖的区域为感测红光和红外光的最敏感的区域。在利用红光和红外光进行血氧饱和度测试时，光电探测器24的设置有第一滤光部243的区域为主要感测红光和红外光的区域。
同理，当绿光照射到光电探测器24时，第二滤光部244可选择性地使绿光透过，第一滤光部243可选择性地阻挡绿光。因此，光电二极管242被第二滤光部244覆盖的区域为感测绿光最敏感的区域。在利用绿光进行心率测试时，光电探测器24的设置有第二滤光部244的区域为主要感测绿光的区域。
因此，本申请实施例的PGG传感器，在利用发绿光的LED进行心率测试时，光电探测器主要利用设置有第二滤光部的区域(即，对绿光最敏感的区域)进行感测；而在利用发红光的LED和红外光的LED进行血氧饱和度测试时，光电探测器主要利用设置有第一滤光部的区域(即，对红光和红外光最敏感的区域)进行感测。如此，光电探测器对心率的测量和对血氧饱和度的测量相对解耦，能够实现高信噪比，提高测量精度。
具体地，当该PPG传感器20利用发红光的LED和发红外光的LED进行血氧饱和度测量时，红光和红外光经人体的血液和组织反射、吸收后形成衰减光，该衰减光透过第一滤光部243被光电二极管242接收。光电二极管242将接收到的衰减光转换为电信号。该电信号经放大、滤波等信号处理后得到第一PPG信号和第二PPG信号。处理器根据第一PPG信号和第二PPG信号可确定氧合血红蛋白和血红蛋白的比值，进而计算出用户的目标部位的血氧饱和度。由于在利用红光和红外光进行血氧饱和度测量时，绿光会被第一滤光部243阻挡。因此，可减少血氧饱和度检测时的噪声，进而提升血氧饱和度检测的信噪比。
同理，当该PPG传感器20利用发绿光的LED进行心率测试时，绿光经人体的血液和组织反射、吸收后形成衰减光，该衰减光透过第二滤光部244被光电二极管242接收。光电二极管242将接收到的衰减光转换为电信号。该电信号经放大、滤波等信号处理后得到第三PPG信号。处理器根据第三PPG信号确定待检测用户的心率。由于在利用绿光进行心率检测时，部分人体发射出来的红外信号和外界环境红外信号被第二滤光部244阻挡。因此，可减小心率检测的噪声，进而提升心率检测的信噪比。
需要说明的是，第一滤光部243和第二滤光部244可通过镀膜的方式形成在光电二极管242的特定区域。第一滤光部243可通过吸收或反射的方式阻挡绿光。第二滤光部244可通过吸收或反射的方式阻挡红光和红外光。一些实施例中，光电二极管242为全光谱敏感的光电二极管，但是该光电二极管242对红光和红外光的敏感性和该光电二极管242对绿光的敏感性不同。具体地，该光电二极管242对红光和红外光的敏感性和该光电二极管242对绿光的敏感性比例大致为(1.6～1.3)：1。也就是说，同一颗光电二极 管242接收1mW/cm2光辐射照度的红光及红外光，和绿光照射，产生的光生电流比为(1.6～1.3)：1。因此，一些实施例中，沿光电二极管242的厚度方向上，所有的第一滤光部243在光电二极管242上的投影的总面积与所有的第二滤光部244在光电二极管242上的投影的总面积之比为1：(1.6～1.3)，以使得光电探测器24对收1mW/cm2光辐射照度的红光及红外光照射产生的光生电流与光电探测器24对收1mW/cm2光辐射照度的绿光照射产生的光生电流大致相当。如图9所示，光电探测器24对520nm左右的绿光的敏感度和其对860nm左右的红外光的敏感度大致相当。
在一些实施例中，所有的第二滤光部244在光电二极管242上的投影的总面积与所有的第一滤光部243在光电二极管242上的投影的总面积之比例如为(1.6：1)、(1.5:1)、(1.4:1)、(1.3：1)等。其中，当该比例为1.5:1时，光电探测器对520nm左右的绿光的敏感度和其对860nm左右的红外光的敏感度最为接近。具体地，通过使第一滤光部243在光电二极管242上的投影的总面积小于第二滤光部244在光电二极管242上的投影的总面积，使得当该PPG传感器20利用发绿光的LED进行心率测试时，即使部分人体发射出来的红外信号和外界环境红外信号入射至第一滤光部243被光电二极管242感测到，由于所有的第一滤光部243在光电二极管242上的投影的总面积与所有的第二滤光部244在光电二极管242上的投影的总面积相比较小，光电二极管242接收该人体发射出来的红外信号和外界环境红外信号后，对应该人体发射出来的红外信号和外界环境红外信号能够产生的光电流较小，如此，可减小心率检测的噪声，进而提升心率检测的信噪比。
在一些实施例中，每一个第一滤光部243在光电二极管242上的投影的面积与每一个第二滤光部244在光电二极管242上的投影的面积相同，通过调整第一滤光部243和第二滤光部244的数量的比例，使所有的第一滤光部243在光电二极管242上的投影的总面积与所有的第二滤光部244在光电二极管242上的投影的总面积之比为1：(1.6～1.3)。
另一些实施例中，第一滤光部243和第二滤光部244的数量相同，可通过调整每一个第一滤光部243在光电二极管242上的投影的面积与每一个第二滤光部244在光电二极管242上的投影的面积的比值，使所有的第一滤光部243在光电二极管242上的投影的总面积与所有的第二滤光部244在光电二极管242上的投影的总面积之比为1：(1.6～1.3)。
具体地，如图8所示，多个第一滤光部243和多个第二滤光部244呈矩阵排布为多行多列。其中，多行多列中，每一行为一个第一滤光部243和一个第二滤光部244交替周期性重复排布，每一列为一个第一滤光部243和一个第二滤光部244交替周期性重复排布。第一滤光部243和第二滤光部244的数量相同。第一滤光部243在光电二极管242上的投影和第二滤光部244在光电二极管242上的投影均为矩形，且第一滤光部243的宽度和第二滤光部244的宽度相同。因此，可通过调整第一滤光部243的长度和第二滤光部244的长度的比值为1：(1.6～1.3)，使所有的第一滤光部243在光电二极管242上的投影的总面积与所有的第二滤光部244在光电二极管242上的投影的总面积之比为1：(1.6～1.3)。
在其他实施例中，第一滤光部243和第二滤光部244的形状及排布规则不限于此。例如，第一滤光部243和第二滤光部244的数量不同，每一个第一滤光部243的面积和第二滤光部244的面积也不同，但所有的第一滤光部243在光电二极管242上的投影的总面积与所有的第二滤光部244在光电二极管242上的投影的总面积之比为1：(1.6～1.3)。
本申请实施例的PPG传感器，光电二极管对多波段(红光波段、绿光波段、红外光波段)敏感，通过设置第一滤光部选择性地透过红光和红外光，设置第二滤光部选择性地透过绿光，相较于图1所示的现有技术，本申请实施例的PPG传感器，光电探测器对心率的测量和对血氧饱和度的测量相对解耦，能够实现高信噪比，提高测量精度。此外，相较于图2所示的现有技术，相同的占板面积情况下，本申请实施例的PPG传感器在利用绿光测量心率和利用红灯、红外测量血氧饱和度时，有效感测面积更大，信噪比更高。例如，在使用绿光进行心率测试时，图2所示的PPG传感器中只有被虚线所覆盖的PD2用于检测，而被虚线所覆盖的两个PD1不能感测绿光，PPG传感器的有效感测绿光的面积为PD2的总体感光面积(设为A)；而本申请实施例的PPG传感器中，如图4所示，被虚线所覆盖的三个光电探测器24均能够感测绿光，假如每个光电探测器24中，有效感测绿光的面积与有效感测红光和红外光的面积相同，那么本申请实施例中，PPG传感器20的有效感测绿光的面积为A×50％×3＝1.5A，如此增强了PPG传感器20感测的绿光的感应信号值，提升了心率检测的信噪比。
其他实施例中，PPG传感器包括的多个光电探测器中，针对不同的光电探测器，第一滤光部在光电二极管上的投影的总面积与所有的第二滤光部在光电二极管上的投影的总面积之比可不同。电子设备的处理器可处理一个或多个光电探测器生成的PPG信号。例如，部分光电探测器中，所有的第一滤光部的总面积大于或等于所有的第二滤光部的总面积，该部分光电探测器(为描述方便，定义该部分光电探测器为第一光电探测器)对红光和红外光的感测比对绿光的感测更灵敏；而另一些光电探测器中，所有的第一滤光部的总面积小于所有的第二滤光部的总面积，该另一些光电探测器(为描述方便，定义该另一些光电探测器为第二光电探测器)对绿光的感测比对红光和红外光的感测更灵敏。
具体地，针对用户使用电子装置测量血氧饱和度的场景，电子装置的处理器可选择开启对红光和红外光的感测更灵敏的第一光电探测器，而关闭第二光电探测器，通过使用对红光和红外光的感测更灵敏的第一光电探测器，提高对血氧饱和度测量的准确度。同理，针对用户使用电子装置测量心率的场景，电子装置的处理器可选择开启对心率感测更灵敏的第二光电探测器，而关闭第一光电探测器，通过使用对心率感测更灵敏的第二光电探测器，提高对心率测量的准确度。可以理解，针对用户使用电子装置测量心率(或血氧饱和度)的场景，电子装置的处理器也可同时开启第一光电探测器和第二光电探测器，通过对多个第一光电探测器和多个第二光电探测器生成的PPG信号进行处理运算，来测量心率(或血氧饱和度)。
此外，需要说明的是，PPG传感器不限于为应用于智能手表中，例如，PPG传感器还可应用于智能手环中；或者，PPG传感器也可环绕用户的其他身体部位(如，头部、脚踝或手指)，应用于其他可穿戴装置中。其他可穿戴装置例如为头戴式设备(如，智能头盔)、服装型设备(如，智能服装、智能手套、臂带)等。
更具体地，PPG传感器可附着或集成到用户的鞋、袜子、领带、衬衫的袖子或领子、裤子或裙子的腰带上等。进一步地，PPG传感器还可从用户的鞋或服装上拆卸下来。例如，当利用PPG传感器检测用户的生理特征时，可将PPG传感器附着到用户的鞋或服装上，当检测完毕后，可将PPG传感器从用户的鞋或服装上拆卸下来。如此，可针对不同 的用户、和/或针对同一用户不同的身体部位，来选择PPG传感器需要贴附的位置，使得PPG传感器的应用场景多样且灵活。
此外，PPG传感器也可应用到具有健康检测功能的设备中，如血氧测量仪、心率检测仪等，但不限于此。
以上实施方式仅用以说明本申请的技术方案而非限制，尽管参照以上较佳实施方式对本申请进行了详细说明，本领域的普通技术人员应当理解，可以对本申请的技术方案进行修改或等同替换都不应脱离本申请技术方案的精神和范围。

Claims (13)

  1. 一种光电探测器，其特征在于，包括：
    光电二极管，用于感测第一波段、第二波段和第三波段的光；
    至少一个第一滤光部，位于所述光电二极管上，用于透过所述第一波段和所述第二波段的光，并阻挡所述第三波段的光；以及
    至少一个第二滤光部，位于所述光电二极管上，用于透过所述第三波段的光，并阻挡所述第一波段和所述第二波段的光。
  2. 如权利要求1所述的光电探测器，其特征在于，所述第一波段在红光光谱之内，所述第二波段在红外光谱之内，所述第三波段在绿光光谱之内。
  3. 如权利要求1或2所述的光电探测器，其特征在于，沿所述光电二极管的厚度方向上，所述至少一个第一滤光部在所述光电二极管上的投影的面积与所述至少一个第二滤光部在所述光电二极管上的投影的面积之比为1：(1.6～1.3)。
  4. 如权利要求3所述的光电探测器，其特征在于，所述第一滤光部与所述第二滤光部的数量相同，沿所述光电二极管的厚度方向上，每一所述第一滤光部在所述光电二极管上的投影的面积与每一所述第二滤光部在所述光电二极管上的投影的面积之比为1：(1.6～1.3)。
  5. 如权利要求1至4中任意一项所述的光电探测器，其特征在于，多个所述第一滤光部和多个所述第二滤光部呈矩阵排布为多行多列；所述多行多列中，每一行为一个所述第一滤光部和一个所述第二滤光部交替周期性重复排布，每一列为一个所述第一滤光部和一个所述第二滤光部交替周期性重复排布。
  6. 如权利要求1至5中任意一项所述的光电探测器，其特征在于，沿所述光电二极管的厚度方向上，所述第一滤光部在所述光电二极管上的投影为矩形，所述第二滤光部在所述光电二极管上的投影为矩形。
  7. 如权利要求6所述的光电探测器，其特征在于，沿所述光电二极管的厚度方向上，所述第一滤光部在所述光电二极管上的投影所形成的矩形的宽度与所述第二滤光部在所述光电二极管上的投影所形成的矩形的宽度相同。
  8. 如权利要求3所述的光电探测器，其特征在于，沿所述光电二极管的厚度方向上，每一所述第一滤光部在所述光电二极管上的投影的面积与每一所述第二滤光部在所述光电二极管上的投影的面积相同，所述第一滤光部与所述第二滤光部的数量之比为1：(1.6～1.3)。
  9. 一种PPG传感器，其特征在于，包括：
    如权利要求1至8中任意一项所述的光电探测器；
    第一光源，用于发出第一光信号，所述第一光信号经用户的皮肤/组织反射的光至少部分位于所述第一波段；
    第二光源，用于发出第二光信号，所述第二光信号经用户的皮肤/组织反射的光至少部分位于所述第二波段；以及
    第三光源，用于发出第三光信号，所述第三光信号经用户的皮肤/组织反射的光至少部分位于所述第三波段；
    其中，所述光电探测器用于接收所述第一波段的光并生成第一PPG信号、接收所述第二波段的光并生成第二PPG信号以及接收所述第三波段的光并生成第三PPG信号，所述第一PPG信号、所述第二PPG信号和所述第三PPG信号用于检测用户的生理特征。
  10. 如权利要求9所述的PPG传感器，其特征在于，所述PPG传感器包括光源组，所述光源组包括所述第一光源、所述第二光源和所述第三光源，多个所述光电探测器环绕所述光源组间隔设置。
  11. 如权利要求10所述的PPG传感器，其特征在于，所述PPG传感器包括间隔设置的多个所述光源组。
  12. 如权利要求9至11中任意一项所述的PPG传感器，其特征在于，所述生理特征包括血氧饱和度和心率，所述第一光信号为红光，所述第二光信号为红外光，所述第一PPG信号和所述第二PPG信号用于检测用户的血氧饱和度，所述第三光信号为绿光，所述第三PPG信号用于检测用户的心率。
  13. 一种电子设备，其特征在于，包括如权利要求9至12中任意一项所述的PPG传感器。
PCT/CN2022/116614 2021-12-07 2022-09-01 光电探测器、ppg传感器及电子设备 WO2023103485A1 (zh)

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