Photoelectric volumetric sensor device

Abstract

This application discloses an apparatus comprising: a photoplethysmography sensor head including a light emitter and a photodetector, wherein the photodetector is arranged diagonally relative to the optical path from the light emitter to the photodetector; and an opaque mask on the photodetector, the mask at least partially covering half of the photodetector at a greater distance from the light emitter, and exposing the other half of the photodetector.

Description

Technical Field

[0001] This invention relates to the field of optical biometry, and in particular to photoelectric volumetric recording for measurement users. Technical Background

[0002] Electrocardiograms (ECGs) can be measured using various sensors. Photoplethysmography (PPG) sensors are an example of ECG sensors. A PPG sensor typically includes at least one light source (e.g., a light-emitting diode (LED)) and at least one photodetector (e.g., a photodiode). Light emitted by the LED(s) is directed to the skin of the user wearing the PPG sensor, and the light is transmitted through the skin to the photodiode. An electrocardiogram (ECG) sensor is another type of heart activity sensor, configured to measure electrical heart activity using one or more electrodes attached to the user's skin.

[0003] The physical dimensions of the light source and the photoelectric sensor form a rectangle. Figure 1 The diagram illustrates a conventional arrangement of a rectangular photoelectric sensor relative to a light source. The light source (light emitter 10) and the photoelectric sensor (photodetector 12) are arranged such that the side of the photoelectric sensor closest to the light source is substantially perpendicular to the line from the light source to the photoelectric sensor. Figure 1 The direction of the dashed line (in the diagram). In other words, the photodetector is viewed as a rectangle when viewed from the light source. It has been observed that this arrangement is not optimal for PPG measurements. This is indicated by the curve above photodetector 12.

[0004] The curve graph shows the trend along the line. Figure 1 The intensity of light received from the light emitter at various points in the photodetector of the specially arranged array further represents the ratio between the pulsating (AC) and non-pulsating (DC) components of the PPG measurement signal. The AC / DC ratio is important in the detection of cardiac activity because a larger AC / DC ratio means a larger AC component and a larger amplitude of the PPG measurement signal, thus enabling better detection of PPG signal peaks. Light intensity is important in relation to the portion of the light propagating from the light emitter 10 relative to noise reflections. Greater intensity means a greater signal-to-noise ratio. For example... Figure 1 As shown, the specific arrangement of the photodetector 12 relative to the light emitter results in a solution where the light intensity is maximized at the portion of the photodetector 12 where the AC / DC component is at its minimum. Typically, the curve is inversely proportional to the spatial distribution of the photodetector. At any particular point on the photodetector, the intensity or AC / DC component is relatively small. Summary of the Invention

[0005] This invention is defined by the independent claims. Various embodiments are provided in the dependent claims. Attached Figure Description

[0006] The present invention will now be described in more detail with reference to the accompanying drawings and preferred embodiments, in which:

[0007] Figure 1 This illustrates the conventional arrangement of the head of the photoelectric volumetric imaging sensor;

[0008] Figure 2 This describes a system to which embodiments of the present invention can be applied;

[0009] Figure 3 This illustrates the arrangement of the photoelectric volumetric sensor head according to an embodiment;

[0010] Figure 4 Some embodiments of masked photodetectors are shown;

[0011] Figure 5 This illustrates the arrangement of the photoelectric volumetric imaging sensor head according to another embodiment; and

[0012] Figure 6 This illustrates the arrangement of the housing for the head of a photoelectric volumetric sensor according to any embodiment described herein. Detailed Implementation

[0013] The following embodiments are exemplary. Although the specification may refer to "a," "an," or "some" embodiments in multiple places in the text, this does not necessarily mean that the same embodiment is mentioned every time, or that a particular feature applies only to a single embodiment. Individual features of different embodiments may also be combined to provide other embodiments.

[0014] Figure 2 This illustrates a system to which embodiments of the present invention can be applied. The system can be used to monitor the physical training, activity, and / or inactivity of user 100. Therefore, the embodiments are not limited to monitoring and / or measuring the physical training of user 100; thus, the system can be used to monitor physical activity and / or inactivity during the day and / or night (e.g., 24 hours a day). This can be achieved by using... Figure 1 This is achieved through one or more of the means described in the examples below.

[0015] refer to Figure 1User 100 may wear wearable devices, such as wrist device 102, head sensor unit 104C, torso sensor 104B, and / or leg sensor 104A. In another example, the wearable device may be glasses and / or included within glasses. In another example, the wearable device includes or is configured to connect to clothing (or apparel). Examples of such clothing may include bras, swimwear (e.g., swimsuits or caps), and gloves. The clothing or apparel may be worn by the user. In some embodiments, the wearable device is integrated as part of the clothing or apparel. For simplicity, we will refer to the wearable device below as wrist device 102. However, the embodiments described with respect to wrist device 102 can be used for other types of wearable devices, i.e., the embodiments are not necessarily limited to wrist device 102.

[0016] Wrist device 102 can be, for example, a smartwatch, smart device, sports watch, and / or activity tracking device (e.g., bracelet, armband, wristband, mobile phone). Wrist device 102 can be used to monitor the physical activity of user 100 using data from internal sensors included in wrist device 102, data from external sensor devices 104A-C, and / or data from an external server (e.g., training database 112). Information related to physical activity can be received from network 110, as the network can include, for example, information related to physical activity from user 100 and / or some other users. Therefore, wrist device 102 can be used to monitor information related to physical activity from user 100 and / or other users. Of course, one or more external sensor devices 104A-C can be worn by other users, so information received from said one or more sensor devices 104A-C can be monitored by user 100 from wrist device 102. Network 110 can include training database 112 and / or server 114. Server 114 can be configured to transfer data between training database 112 and some external devices (such as wearable devices). Therefore, database 112 can be used to store cardiac activity measurement data, for example.

[0017] It should be understood that the wrist device 102 can be used to monitor the physical activities of the user 100 and / or function as a smartwatch configured to communicate with, for example, a portable electronic device 106, a network 110, and / or other networks (e.g., cellular networks). Therefore, the wrist device 102 can connect (i.e., wirelessly connect) to the portable electronic device 106, such as a mobile phone, smartphone, tablet, and / or computer. This enables data transfer between the wrist device 102 and the portable electronic device 106. For example, data transfer can be based on the Bluetooth protocol. Other wireless communication methods, such as wireless local area networks (WLAN) and / or near field communication (NFC), can also be used.

[0018] The wrist device 102 may include a cardiac activity sensor configured to determine the cardiac activity of the user 100, such as heart rate, heart rate interval (HBI), and / or heart rate variability (HRV). The cardiac activity sensor may include an optical cardiac activity sensor unit configured to measure the user 100's cardiac activity using optical measurements. An example of such a sensor is a PPG (photoplethysmography) sensor. The sensor head of the PPG sensor may include one or more light-emitting diodes (LEDs) as light emitters and a photodetector, such as a photodiode. Optical measurements may include the LEDs emitting light toward the user 100's body tissue and measuring light reflected, diffracted, scattered, and / or emitted from the user 100's body tissue using a photodiode. The emitted light is modulated as it travels through the user 100's veins, and this modulation may be detected by the optical cardiac activity sensor unit. By using the detected optical measurement data, the wrist device 102 can determine the user 100's cardiac activity, such as heart rate. The optical cardiac activity sensor unit can acquire measurement signals characterizing or carrying information about the user's cardiac activity through measurement. As understood, similar cardiac activity circuitry can be included in other wearable devices described herein.

[0019] It should also be noted that the cardiac activity circuitry can generate raw measurement data of cardiac activity, and / or it can process the measurement data into cardiac activity information, such as heart rate. Sensors in the cardiac activity circuitry may include data processing capabilities. Furthermore, the wrist device 102 and / or some other wearable devices may include processing circuitry configured to acquire cardiac activity measurement data from the cardiac activity circuitry and process the data into cardiac activity information, such as cardiac activity measurements characterizing the cardiac activity of user 100. For example, measurement data from an optical cardiac activity sensor unit can be used by the processing circuitry to determine user 100's heart rate, HRV, and / or HBI. Moreover, the raw measurement data and / or processed information can be processed by the wrist device 102 or some other wearable devices, and / or transmitted to an external device, such as portable electronic device 106.

[0020] The wrist device 102 (or more broadly, the wearable device) may include other types of sensors. Such sensors may include laser Doppler-based blood flow sensors, magnetic blood flow sensors, electromechanical membrane (EMFi) pulse sensors, temperature sensors, pressure sensors, electrocardiogram (ECG) sensors, and / or polarized blood flow sensors.

[0021] A wearable device including a PPG sensor head may include a housing and a securing mechanism configured to attach the housing to an object, such as a user 100. If the portable training computer is a wrist-worn computer, the securing mechanism may be a wristband. The securing mechanism may also be clothing, to which the portable training computer may be integrated or removably attached. The housing may house at least some of the electronic circuitry of the portable training computer. The housing may also store the power source for the portable training computer, such as a battery.

[0022] Communication circuitry can provide wearable devices with the ability to wirelessly send and receive signals and data. The communication circuitry may include a radio modem configured to operate according to one or more radio communication protocols (such as Bluetooth, developed within the Bluetooth Special Interest Group (SIG)). It operates using (technology). Supported Bluetooth technologies may include Bluetooth Smart. Bluetooth The modem may use Bluetooth Low Energy (BTLE), or any one or more Bluetooth evolution versions typically from version 1.0 to 5.0 and future versions. In another embodiment, the radio modem supports another communication technology, such as Global Navigation Satellite System (GNSS) technology, such as Global Positioning System or Galileo positioning system. In another embodiment, the radio modem supports Ultra Wideband (UWB) technology. In embodiments, the portable training computer includes multiple radio modems that support different radio communication protocols and operate on different frequency bands. According to a particular embodiment, the communication circuitry may be used to transmit data acquired from the PPG measurement signal to any of the devices 102, 106, 114.

[0023] Figure 3 This indicates a PPG sensor head used in any of the aforementioned devices (which include a PPG sensor). Reference Figure 3 The PPG sensor head includes a light emitter 31 (which may be similar to light emitter 10) and a photodetector 30. The light emitter may include a light-emitting diode. The photodetector 30 is arranged diagonally relative to the light path from the light emitter to the photodetector. Figure 1 Rotating the arrangement by approximately 45 degrees will provide different light intensity curves. The AC / DC curves remain basically similar. Figure 1 The arrangement of the AC / DC curves. Figure 1 The light intensity curve of the arrangement is plotted on Figure 3 The light intensity graph (dash line) is used for comparison. It can be seen that the light intensity curve of the diagonal photodetector has its maximum value at the midpoint of the photodetector, where the light intensity curve along the path from the light emitter 31 to the photodetector (…) Figure 3 The horizontal dashed line (in the image) is the widest. Light intensity decreases approximately exponentially after the midpoint. Now, the light intensity is also high or at least greater than [value missing] in the AC / DC component. Figure 1 The photodetector is positioned relatively high in certain areas. This means that the light component collected by the corresponding region of the photodetector has a high signal-to-noise ratio and a high AC / DC ratio, thus relative to... Figure 1 The arrangement increased the amplitude of the PPG measurement signal.

[0024] Because light intensity decreases quite rapidly at the half of the photodetector furthest from the light emitter, the light component collected by the more distant half has a lower signal-to-noise ratio, even though AC / DC is at its highest. Due to this characteristic, it would be advantageous to mask at least some portion of the more distant half of the photodetector surface to improve the overall signal-to-noise ratio of the PPG measurement signal. For masking purposes, an opaque mask 32 is arranged above the photodetector 30. This mask 32 at least partially covers the half of the photodetector furthest from the light emitter 31, thus exposing the other half of the photodetector to collect light from the light emitter.

[0025] Needless to say, the light emitter and photodetector are arranged on the same plane or substrate, and the aforementioned distance is measured on this plane. In the case of a PPG sensor, both the light emitter and photodetector are arranged on the same plane and point in the same general direction toward the skin. The light emitter emits light in this direction, while the photodetector collects light from this direction.

[0026] The mask can cover most of the far half of the photodetector, including, for example, the corner furthest from the light emitter. The mask can cover only the farthest corner of the photodetector, or it can cover three of the four corners and the far half of the photodetector, thus exposing the corner closest to the light emitter to light.

[0027] The photodetector can be square or rectangular, rotated diagonally from the perspective of the light emitter. The definition of square or rectangular also applies to squares or rectangles with sharp corners and squares or rectangles with rounded corners. Alternatively, the photodetector can be parallelogram or rhombus, or another geometry with four or at least four corners.

[0028] Mask 32 can be implemented using any physical component or coating on the photodetector that achieves an opaque feature and prevents light from reaching the covered portion of the photodetector 30. Therefore, light components with low signal-to-noise ratios are eliminated from the PPG measurement signal measured by the photodetector, thereby improving the signal-to-noise ratio of the PPG measurement signal and increasing its amplitude.

[0029] Next, we will explain the meaning of diagonal orientation. In the apparatus of claim 1, the photodetectors are aligned such that the diagonal of the photodetectors is in the same direction as the optical path. Figure 3 The diagonal in the diagram is drawn by the horizontal dashed line passing through the photodetector. It should be understood that some deviation is permissible without substantially altering the light intensity distribution. Therefore, the diagonal can, for example, deviate from the direction of the light path by 10 degrees or less. Rotation significantly shifts the light intensity distribution towards... Figure 1 The change in light intensity distribution brings the peak of light intensity to the region where the AC / DC component is lower.

[0030] From another perspective, diagonal orientation can be understood as follows: when viewed from the direction of the light emitter 31, the photodiode appears as having a diagonal (rhomboid) shape, rather than a rectangular (square) shape. This means that from... Figure 1 Rotating the azimuth by at least 20 degrees will push the light intensity peak to the region with higher AC / DC components, thus providing some benefit to the amplitude of the PPG measurement signal.

[0031] From another perspective, the diagonal orientation can be understood as making the point (corner) of the photodetector 30 (rather than the side) the part of the photodetector that has the shortest distance to the light emitter 31.

[0032] It should be understood that the light emitter 31 and the photodetector 30 form a PPG sensor, which is configured to measure the PPG measurement signal together. A light emitter is needed to emit light onto the skin of the user 10, and a photodetector is needed to collect the emitted light traveling from the light emitter through the skin. Clearly, the light is collected by the exposed portion of the photodetector.

[0033] We then disclose some embodiments of how the mask at least partially covers the more distant half of the photodetector when viewed from the light emitter. The more distant half can be defined as a continuous or uniform region of the photodetector that starts from the point of the photodetector 30 furthest from the light emitter 31 and extends toward the light emitter 31. Figure 4 Some embodiments are illustrated in which less than half of the photodetector is covered by a mask, but the covered portion covers a specific amount of the area furthest from the light emitter. The mask can be symmetrical or asymmetrical with respect to the shape of the photodetector, such as... Figure 4 As shown.

[0034] exist Figure 3 In one embodiment, mask 32 completely covers half of the photodetector at the greater distance from the light emitter. This is in the case where the photodetector is asymmetrical from the viewpoint of the light emitter, for example, the photodetector relative to... Figure 1The photodetector is rotated greater than zero degrees but less than 45 degrees, and the mask can cover half of it, forming a continuous or uniform region starting from the farthest point of the photodetector relative to the light emitter and extending from there toward the photoemitter.

[0035] In one embodiment, the device includes another light emitter, and the photodetector is arranged diagonally relative to the optical path from the other light emitter to the photodetector. Figure 5 An embodiment is illustrated in which light emitters 31 and 51 are arranged such that a photodetector 50 (which may be the same as photodetector 30) is diagonally opposite to the two light emitters 31 and 51. In other words, different corners of the photodetector may point to different light emitters 31 and 51. The light emitters 31 and 51 may be arranged on the same side of the photodetector, but at different angles from the photodetector's perspective. The light emitters may be arranged in the same general direction from the photodetector, thus leaving at least a portion of the photodetector furthest from the two light emitters 31 and 51.

[0036] Similar to Figure 3 In one embodiment, the mask 52 may at least partially cover half of the photodetector at a greater distance from the other light emitter, leaving the other half of the photodetector exposed. Figure 5 An embodiment of the area covered by this mask is shown. In Figure 5 In the arrangement, straight lines from light emitter 31 and another light emitter 51 are drawn to pass through the photodetector. Lines with intersection points divide the photodetector's photodetection area into multiple quadrants. The mask at least partially covers the quadrant of the photodetector at its maximum distance from light emitter 31 and the other light emitter 51.

[0037] Typically, the exposed portion of a photodetector can form a triangular or combined region of multiple triangles (excluding the rectangle that forms the combined region), wherein each light emitter faces at least one corner of a triangle. Figure 3 In this embodiment, the triangle is easily visible. Figure 5 In the embodiments, the exposed area is determined according to and Figure 3 It is formed by two triangles with the same logic.

[0038] In an embodiment, the device described in conjunction with any of the above embodiments includes a circuit board housing light emitters 31, 51 and photodetector 30. Figure 6An embodiment is illustrated in which the circuit board is more typically represented by a substrate 60. The circuit board can be a rigid or flexible printed circuit board. The device may also include a cover 66 disposed on the circuit board. The cover includes a first window 62 at the location of the light emitter and a second window 63 at the location of the photodetector 30. In embodiments with multiple light emitters, corresponding windows may be provided. The windows may be holes etched into the cover or made of a transparent material that fills or covers the holes. For example, the cover may be metal or plastic and also includes a transparent layer covering the windows 62, 63 to prevent the holes from becoming blocked. Figure 6 In one embodiment, mask 32 is disposed within the cover and connected to the second window. The mask may be an integral part of the cover body and have the same material as the cover 66. Therefore, the mask can be implemented by etching the second window 63 such that it exposes only the half (partial) of the photodetector closer to the light emitter and designed to be exposed according to the above embodiment. Thus, the implementation of mask 32 does not require additional components or layers and can be formed by the cover itself. However, other embodiments may implement the mask as a separate component arranged to connect to the second window 63 in the cover 66.

[0039] Figure 6 The side and top views of the device are shown, which also show the orientation and diagonal shape of the photodetector 30 relative to the light emitter 31.

[0040] In one embodiment, the cover has at least one opaque protrusion 65 extending toward the circuit board between the light emitter 31 and the photodetector 30, thereby blocking direct light propagation from the light emitter to the photodetector within the device. In other words, the outer surface of the cover (designed to face the skin) can define a surface or plane, and the protrusion extends from that plane toward the substrate, and in one embodiment, the protrusion extends to contact the substrate directly or via a gasket or seal 64. As described above, the purpose of the inner wall is to prevent optical noise at the photodetector. The protrusion can extend at least to such an extent that it blocks direct line-of-sight from the light emitter to the photodetector at least for most of the surfaces of the light emitter and the photodetector that face each other. In other words, there is no direct line-of-sight from the surface of the light emitter facing the photodetector to most of the surface of the photodetector facing the light emitter. In one embodiment, there is no direct line-of-sight between the two surfaces. This reduces optical noise compared to conventional solutions where the inner wall protrudes from the substrate toward the cover or is configured as an additional component (thus leaving a small gap between the inner wall and the cover and / or the substrate). Light from the light emitter can reach the photodetector through this gap, thus causing optical noise. The inner wall can be an integral part of the cover, for example, made of the same homogeneous material as the rest of the cover.

[0041] Those skilled in the art will readily recognize that the inventive concept can be implemented in various ways as technology advances. The invention and its embodiments are not limited to the examples described above, but can be varied within the scope of the claims.

Claims

1. An apparatus comprising: A photoelectric volumetric sensor head includes a light emitter and a photodetector arranged on the same plane, wherein the photodetector is arranged diagonally relative to the optical path from the light emitter to the photodetector, and wherein the shape of the photodetector has at least four corners, and the shape of the photodetector has been rotated to the diagonal orientation from the viewpoint of the light emitter. An opaque mask is placed on top of a photodetector, the mask at least partially covering the half of the photodetector furthest from the light emitter, thereby preventing light from the light emitter from reaching the covered portion of the photodetector, while exposing the other half of the photodetector to collect light from the light emitter. The mask covers a continuous region of the photodetector, the continuous region starting from the point of the photodetector furthest from the light emitter and extending towards the light emitter. Another light emitter, wherein a photodetector is arranged diagonally relative to the optical path from the other light emitter to the photodetector, wherein a mask at least partially covers the half of the photodetector that is farther away from the other light emitter, and exposes the other half of the photodetector.

2. The apparatus according to claim 1, wherein: The photodetectors are aligned so that their diagonals are aligned with the optical path.

3. The apparatus according to claim 1, wherein: The mask completely covers the half of the photodetector that is furthest from the light emitter.

4. The apparatus according to claim 1, wherein: The light emitter and another light emitter are arranged on the same side of the photodetector, but at different angles from the perspective of the photodetector.

5. The apparatus according to claim 1, wherein: The photodetector's photodetector region is divided into multiple quadrants by the intersection of a straight line passing through the light emitter and another light emitter. The mask at least partially covers the quadrant of the photodetector that is furthest from both the light emitter and the other light emitter.

6. The apparatus according to claim 1 or 2, wherein: The light emitter is configured to emit light toward the user's skin when the device is attached to the user, and The photodetector is configured to collect light emitted by the light emitter and traveling through the skin using at least half of the exposed area, and to generate a photoplethysmography measurement signal based on the collected light.

7. The apparatus according to claim 1 or 2, wherein: The device is a wearable training computer.

8. The apparatus according to claim 1 or 2, further comprising: A circuit board that houses a light emitter and a photodetector; as well as A cover is disposed on a circuit board, wherein the cover includes a first window at the location of a light emitter and a second window at the location of a photodetector, and a mask is disposed in the cover and connected to the second window.

9. The apparatus according to claim 8, wherein: The cover has at least one opaque protrusion extending toward the circuit board between the light emitter and the photodetector, thereby blocking the direct propagation of light from the light emitter to the photodetector within the device.

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