Optical lens, photoplethysmograph and electronic equipment

Abstract

An optical lens (265), a photoplethysmograph (26) and an electronic device (100) relate to the technical field of electronic devices and are used for solving the problems of how to reduce the reflectivity of light rays at a cover plate, reduce the light emitting angle of the light rays after the light rays are emitted from the cover plate, increase the energy and maximum light intensity of light entering a human body and improve the measurement accuracy and blood perfusion index. The optical lens (265) comprises a light-transmitting substrate (2651) and a micro lens array (2652). The light-transmitting substrate (2651) is provided with a first surface (S1) and a second surface (S2) which are opposite to each other. The micro-lens array (2652) is arranged on the first surface (S1), and the micro-lens array (2652) comprises a first micro-lens group (2652a) and a plurality of second micro-lens group arrays (Ar1). Each of the second microlens group arrays (Ar1) includes a plurality of second microlens groups (2652b) arranged in an array around the first microlens group (2652a). The first microlens group (2652a) and the second microlens group (2652b) each include a first microlens unit (C1) and a second microlens array (Ar2). The second microlens array (Ar2) includes a plurality of second microlenses (T2) arranged in an array around the first microlens unit (C1). The optical lens (265) is used for reducing the light emitting angle.

Description

Optical lens, photoplethysmograph and electronic device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on November 26, 2022, with application number 202211494769.4 and invention name “An optical lens, photoplethysmograph and electronic device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of electronic equipment, and in particular to an optical lens, a photoplethysmograph and an electronic device. Background Art

[0003] Devices such as photoplethysmographs, projectors, cameras, and webcams contain light emitters, which emit light beams for purposes such as heart rate monitoring, illumination, and fill lighting. A translucent cover is typically installed on the light-emitting side of the light emitter to protect it from water, dust, and scratches without obstructing the light path.

[0004] Due to the different refractive indices between the transparent cover and air, light is reflected on the surface of the transparent cover facing the light emitter and the surface facing away from the light emitter, reducing light extraction efficiency and emitting less light energy. Furthermore, the light emitted from the transparent cover has a large angle of exit, resulting in a lower maximum light intensity, which affects the user experience.

[0005] Summary of the Invention

[0006] The embodiments of the present application provide an optical lens, a photoplethysmograph, and an electronic device for solving the problem of how to reduce the reflectivity of light at the cover plate, reduce the light output angle after the light is emitted from the cover plate, and increase the light output energy and maximum light intensity.

[0007] To achieve the above objectives, the embodiments of the present application adopt the following technical solutions:

[0008] In a first aspect, an optical lens is provided, comprising a light-transmitting substrate and a microlens array, wherein the light-transmitting substrate has a first surface and a second surface facing each other. The microlens array is disposed on the first surface, and the microlens array comprises a first microlens group and a plurality of second microlens group arrays. Each second microlens group array comprises a plurality of second microlens groups disposed around the first microlens group array, and the plurality of second microlens group arrays are sequentially arranged radially along the annular array trajectory of the plurality of second microlens groups. The first microlens group and the second microlens group each comprise a first microlens unit and a second microlens array, the first microlens unit comprising at least one first microlens, and the second microlens array comprising a plurality of second microlenses disposed around the first microlens unit array. The first microlens and the second microlens are both convex spheres protruding from the first surface in a direction away from the second surface.

[0009] In this way, when an optical lens is applied between a light emitter and a cover plate, with the first surface of the optical lens facing the light emitter and the second surface facing the cover plate, the first and second microlenses can converge the light beam emitted by the light emitter, reducing the angle of incidence of some light on the surface of the cover plate facing the light emitter and the surface of the cover plate facing away from the light emitter, thereby reducing the amount of light reflected by the cover plate. Furthermore, the first and second microlenses converge the light beam emitted by the light emitter, reducing the light output angle after the light is emitted from the cover plate. At the same time, there is a certain gap between two adjacent second microlens arrays, and these gaps are not provided with convex spheres, which can reduce the energy loss of light when passing through the microlens array. This helps improve light extraction efficiency, increase light output energy and maximum light intensity. At the same time, the microlens array occupies a small height, making it easy to install in electronic equipment with limited space.

[0010] In a possible implementation of the first aspect, two adjacent second microlens group arrays are spaced radially along the annular array trajectory of the multiple second microlens groups and are closely arranged, and the first microlens group and the adjacent second microlens group array are spaced radially along the annular array trajectory of the multiple second microlens groups and are closely arranged. In this way, the number of second microlens group arrays arranged on the first surface is relatively large. This can converge the emitted light beam of the light emitter as much as possible, reducing the incident angle of some light on the surface of the cover plate facing the light emitter and the surface of the cover plate facing away from the light emitter, thereby reducing the amount of light reflected by the cover plate. Moreover, it can converge the emitted light beam of the light emitter as much as possible, reducing the light output angle after the light is emitted by the cover plate. This can improve the light output efficiency, increase the light output energy and maximum light intensity.

[0011] In one possible implementation of the first aspect, within each second microlens group array, multiple second microlens groups are also spaced and closely arranged along the annular array trajectory of the multiple second microlens groups. This allows for a relatively large number of second microlens groups to be arranged within each second microlens group array. This allows for the best possible convergence of the light beam emitted by the light emitter, reducing the angle of incidence of some light on the surface of the cover plate facing the light emitter and the surface of the cover plate facing away from the light emitter, thereby reducing the amount of light reflected by the cover plate. Furthermore, the best possible convergence of the light beam emitted by the light emitter allows for the reduction of the light output angle after the light is emitted from the cover plate. This improves light extraction efficiency, increases light output energy, and increases maximum light intensity.

[0012] In a possible implementation of the first aspect, the second microlens array and the first microlens unit are spaced and closely arranged radially along the annular array trajectory of the plurality of second microlenses. In this way, the first microlens group and the second microlens group occupy a smaller area on the first surface, and a larger number of first microlens groups and second microlens groups can be arranged on the first surface. It is possible to converge the light beam emitted by the light emitter as much as possible, reduce the incident angle of some light on the surface of the cover plate facing the light emitter, and the surface of the cover plate facing away from the light emitter, thereby reducing the amount of light reflected by the cover plate. Moreover, it is possible to converge the light beam emitted by the light emitter as much as possible, and reduce the light output angle after the light is emitted by the cover plate. This can improve the light output efficiency, increase the light output energy and the maximum light intensity.

[0013] In a possible implementation of the first aspect, in the second microlens array, the plurality of second microlenses are also spaced and closely arranged along the annular array trajectory of the plurality of second microlenses. In this way, the number of second microlenses arranged in the second microlens array is relatively large. This can converge the light beam emitted by the light emitter as much as possible, reducing the angle of incidence of some light on the surface of the cover plate facing the light emitter and the surface of the cover plate facing away from the light emitter, thereby reducing the amount of light reflected by the cover plate. Moreover, it can converge the light beam emitted by the light emitter as much as possible, reducing the light output angle after the light is emitted from the cover plate. This can improve the light extraction efficiency, increase the light energy and maximum light intensity entering the human body, and improve measurement accuracy and blood perfusion index.

[0014] In a possible implementation manner of the first aspect, in each of the first microlens units, the number of the first microlens is one, and in the second microlens array, the number of the second microlenses is six.

[0015] In one possible implementation of the first aspect, within the first microlens unit, there are multiple first microlenses, the multiple first microlenses are arranged in a row, and the arrangement direction of the multiple first microlenses within the second microlens group is aligned with the extension direction of the annular array trajectory of the second microlens group array in which the second microlens group is located. This facilitates positioning of the multiple first microlenses within the first surface, thereby reducing design difficulty.

[0016] In one possible implementation of the first aspect, within the first microlens group and the second microlens group, the multiple first microlenses are spaced and closely arranged. The spaced arrangement of the multiple first microlenses means that the spacing between two adjacent first microlenses within the multiple first microlenses is greater than or equal to zero. Furthermore, the closely arranged arrangement of the multiple first microlenses means that the spacing between two adjacent first microlenses is less than or equal to 0.003 mm. This reduces the area occupied by the first microlens units on the first surface, facilitating a reduction in the area occupied by the first and second microlens groups on the first surface, thereby enabling a greater number of first and second microlens groups to be arranged on the first surface. This effectively converges the light beam emitted by the light emitter, reducing the incident angle of some light on the surface of the cover facing the light emitter and the surface of the cover facing away from the light emitter, thereby reducing the amount of light reflected by the cover. Furthermore, the convergence of the light beam emitted by the light emitter can be minimized, reducing the light output angle after the light exits the cover. This improves light extraction efficiency and increases the light energy and maximum light intensity incident on the human body.

[0017] In a possible implementation manner of the first aspect, the number of first microlenses in the first microlens group and the second microlens group is two, and the number of second microlenses in the second microlens array is twelve.

[0018] In a possible implementation manner of the first aspect, the number of first microlenses in the first microlens group and the second microlens group is two, and the number of second microlenses in the second microlens array is six.

[0019] In a possible implementation of the first aspect, the diameter of the area occupied by the first microlens on the first surface is greater than or equal to 0.1 mm and less than or equal to 0.15 mm, and the curvature of the end of the first microlens away from the first surface is 0 mm. -1 The curvature of the end of the first microlens connected to the first surface is greater than or equal to 8 mm -1 and less than or equal to 10mm -1, the height of the first microlens protruding from the first surface is greater than or equal to 0.0252mm and less than or equal to 0.034mm. In this way, the first microlens can better converge the light beam, reduce the incident angle of some light on the surface of the cover plate facing the light emitter, and the surface of the cover plate facing away from the light emitter, thereby reducing the amount of light reflected by the cover plate. Moreover, the first microlens can better converge the light beam and reduce the light exit angle after the light is emitted from the cover plate. This can increase the light energy and maximum light intensity entering the human body, thereby improving measurement accuracy and blood perfusion index.

[0020] In a possible implementation of the first aspect, the diameter of the area occupied by the second microlens on the first surface is greater than or equal to 0.05 mm and less than or equal to 0.1 mm, and the curvature of the end of the second microlens away from the first surface is 0 mm. -1 The curvature of the end of the second microlens connected to the first surface is greater than or equal to 5 mm -1 and less than or equal to 40mm -1 , the height of the second microlens protruding from the first surface is greater than or equal to 0.01mm and less than or equal to 0.0175mm. In this way, the second microlens can better converge the light beam, reduce the incident angle of some light on the surface of the cover facing the light emitter, and the surface of the cover facing away from the light emitter, thereby reducing the amount of light reflected by the cover. Moreover, the second microlens can better converge the light beam and reduce the light exit angle after the light is emitted from the cover. This can increase the light energy and maximum light intensity entering the human body, thereby improving measurement accuracy and blood perfusion index.

[0021] In a possible implementation manner of the first aspect, the microlens array and the light-transmitting substrate are integrally formed, and the material of the microlens array and the light-transmitting substrate includes at least one of glass, sapphire, polyamide, polycarbonate, polymethyl methacrylate, thermoplastic polyurethane elastomer rubber, and transparent nylon.

[0022] In a second aspect, a photoplethysmograph is provided, comprising a cover, a light emitter, a light receiver, and an optical lens. The cover comprises a first light-transmitting portion and a second light-transmitting portion. The light emitter is located on the inner side of the cover, with the light-emitting surface of the light emitter facing the first light-transmitting portion. The light receiver is located on the inner side of the cover, with the light-incident surface of the light receiver facing the second light-transmitting portion. The optical lens is an optical lens as described in any of the above technical solutions, disposed on the surface of the first light-transmitting portion facing the light emitter, with the first surface of the optical lens facing the light emitter and the second surface facing the first light-transmitting portion.

[0023] In this way, the first and second microlenses can be used to converge the light beam emitted by the light emitter, reducing the incident angle of some light on the surface of the cover facing the light emitter and the surface of the cover facing away from the light emitter, thereby reducing the amount of light reflected by the cover. Moreover, by converging the light beam emitted by the light emitter with the help of the first and second microlenses, the light output angle after the light is emitted from the cover can be reduced. At the same time, there is a certain gap between two adjacent second microlens group arrays, and these gaps are not provided with convex spheres, which can reduce the energy loss of light when passing through the microlens array. This is conducive to improving light extraction efficiency, increasing the light energy and maximum light intensity incident on the human body, and improving measurement accuracy and blood perfusion index.

[0024] In one possible implementation of the second aspect, the center of the microlens array of the optical lens is aligned with the center of the light-emitting surface of the light emitter. This effectively converges the light emitted by the light emitter, reduces the amount of light reflected by the cover plate, and reduces the angle of the light emitted from the cover plate.

[0025] In one possible implementation of the second aspect, the optical lens and the first light-transmitting portion are integrally formed. This eliminates any intermediary between the optical lens and the first light-transmitting portion, ensuring light extraction efficiency while also isolating light crosstalk and preventing light leakage between the two portions. Furthermore, the optical lens and the first light-transmitting portion do not require attachment, reducing manufacturing complexity.

[0026] In one possible implementation of the second aspect, the cover further includes a light-shielding portion that is opaque and located at least between the first light-transmitting portion and the second light-transmitting portion. In this manner, the light-shielding portion minimizes the risk of light emitted by the light transmitter from passing directly into the collection range of the light receiver without passing through the detected human body part, thereby preventing the detection accuracy of the photoplethysmograph from being affected.

[0027] In a third aspect, an electronic device is provided, comprising a display screen, a housing, and a photoplethysmograph as described in any of the above technical solutions. The display screen is connected to the housing, which includes a back cover that faces the display screen. A cover plate of the photoplethysmograph is disposed on the back cover, and a light transmitter and a light receiver of the photoplethysmograph are located within the housing.

[0028] Since the electronic device provided in the present application includes the photoplethysmograph described in any one of the technical solutions of the second aspect above, the two can solve the same technical problems and achieve the same effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG1 is a schematic diagram of the structure of an electronic device provided in some embodiments of the present application;

[0030] FIG2 is an exploded view of a watch body in the electronic device shown in FIG1 ;

[0031] FIG3 is a schematic diagram of a cross-sectional structure of the electronic device shown in FIG1 at line CC;

[0032] FIG4 is an enlarged view of the electronic device shown in FIG3 at area I;

[0033] FIG5 is a bottom view of the optical transmitter and optical receiver in the electronic device shown in FIG4 ;

[0034] FIG6 is a top view of the inner cover of the electronic device shown in FIG4 ;

[0035] FIG7 is a schematic structural diagram of the electronic device shown in FIG4 when worn on a user's wrist;

[0036] FIG8 is an enlarged view of an optical lens in the electronic device shown in FIG1 to FIG4;

[0037] FIG9 is a schematic structural diagram of the optical lens shown in FIG8 on the first surface;

[0038] FIG10 is a schematic structural diagram of a first microlens group or a second microlens group in a microlens array within the optical lens shown in FIG9 ;

[0039] FIG11 is a schematic structural diagram of a second microlens array in the optical lens shown in FIG9 ;

[0040] FIG12 is a schematic structural diagram of two adjacent second microlens group arrays in the optical lens shown in FIG9 ;

[0041] FIG13 is a schematic structural diagram of a new array formed by removing one of the second microlens group arrays located in the outer layer of the two adjacent second microlens group arrays shown in FIG12 and arranging the remaining second microlens groups along a ring array;

[0042] FIG14 is a schematic structural diagram of a second microlens array in the optical lens shown in FIG9 ;

[0043] FIG15 is a schematic diagram of the structure of an optical lens on the first surface provided by some other embodiments of the present application;

[0044] FIG16 is a schematic structural diagram of a first microlens group or a second microlens group in a microlens array within the optical lens shown in FIG15 ;

[0045] FIG17 is a schematic diagram of the structure of an optical lens on the first surface provided by some other embodiments of the present application;

[0046] FIG18 is a schematic structural diagram of a first microlens group or a second microlens group in a microlens array within the optical lens shown in FIG17 ;

[0047] FIG19 is a side view of a structure consisting of a single first microlens and a transparent substrate in the first microlens group or the second microlens group shown in FIG10 , FIG16 , or FIG18 ;

[0048] FIG20 is a side view of a structure consisting of a single second microlens in the first microlens group or the second microlens group and a transparent substrate shown in FIG10 , FIG16 , or FIG18 ;

[0049] FIG21 is a schematic diagram of the structure of a photoplethysmograph in an electronic device provided in yet other embodiments of the present application;

[0050] Figure 22 is a structural block diagram of a circuit board assembly in an electronic device provided in some embodiments of the present application. DETAILED DESCRIPTION

[0051] In the embodiments of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0052] In the embodiments of the present application, the terms "comprises," "comprising," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0053] In the embodiments of this application, "and / or" is simply a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0054] The present application provides an optical lens that can be used in a photoplethysmograph. To facilitate understanding of the photoplethysmograph provided in the embodiments of the present application, the following first describes its application scenarios. The photoplethysmograph can be applied to electronic devices such as mobile phones, tablet computers, digital cameras, wearable devices, and other common electronic products, as well as large and small medical devices that use optical methods to measure physiological parameters (heart rate, blood oxygen, blood pressure, blood sugar, etc.). Wearable devices include, but are not limited to, smart watches, smart bracelets, and smart clothing.

[0055] A photoplethysmograph uses photoplethysmograph (PPG) technology to detect changes in the user's heart rate. PPG is a non-invasive technique that uses photoelectric means to measure changes in blood volume in living tissue.

[0056] A photoplethysmograph consists of a light transmitter and a light receiver. The transmitter irradiates a beam of light of a specific wavelength onto the skin surface of the user being tested, which is then reflected by the light receiver. During this process, the blood volume within the blood vessels fluctuates due to the heart's contraction and relaxation. Therefore, when the heart contracts, the blood volume in the peripheral vessels increases, and light absorption also increases, resulting in a lower light intensity detected by the light receiver. Conversely, during diastole, the blood volume in the peripheral vessels decreases, and the light intensity detected by the light receiver is higher. As can be seen, the light intensity detected by the light receiver fluctuates. This light intensity fluctuation is converted into a digital electrical signal, which represents the wearer's heart rate. This heart rate signal can be used to further determine physiological parameters such as the user's blood pressure, blood oxygen, brain oxygen, muscle oxygen, blood sugar, pulse rate, and respiratory rate. Therefore, electronic devices such as smartwatches and smart bracelets currently use photoplethysmographs to track user health.

[0057] Typically, in electronic devices, the light emitter and light receiver are positioned adjacent to each other, and the photoplethysmograph typically includes a cover plate, which protects the light emitter and light receiver from water, dust, and scratches. The light emitted by the light emitter is easily reflected at the cover plate, reducing the light extraction efficiency and reducing the amount of light energy entering the human body. Furthermore, the light emitted by the cover plate has a large angle of emission, resulting in a lower maximum light intensity entering the human body, which affects detection accuracy and the perfusion index (PI), impacting the user experience.

[0058] To this end, an embodiment of the present application provides an improved electronic device.

[0059] The electronic device provided in the embodiments of the present application is described below with reference to the accompanying drawings. Please refer to Figure 1, which is a schematic diagram of the structure of an electronic device 100 provided in some embodiments of the present application. In this embodiment and the embodiments below, the electronic device 100 is illustrated as a smart watch, which is not to be considered as a special limitation on the structural form of the electronic device 100. The smart watch includes a watch body 2 and a watch strap 1. The watch body 2 is used to implement the main functions of the smart watch, and the watch strap 1 is used to wear the watch body 2 on a human wrist.

[0060] In some embodiments, referring again to FIG. 1 , the watchband 1 may include a first strap portion 11 and a second strap portion 12 . One end of the first strap portion 11 and one end of the second strap portion 12 are connected to opposite ends of the watch body 2 . A first locking portion 111 is provided at the other end of the first strap portion 11, and a second locking portion 121 is provided at the other end of the second strap portion 12. The first locking portion 111 and the second locking portion 121 are detachably locked to each other to allow the watch body 2 to be worn on a person's wrist.

[0061] Among them, the matching structure composed of the first locking part 111 and the second locking part 121 can be a watch buckle structure such as a hook buckle, a hidden buckle, a butterfly buckle, a belt snap buckle, a folding safety buckle, a folding buckle or a pin buckle, and this application does not make specific limitations on this.

[0062] The following mainly introduces the watch body 2.

[0063] Continuing with Figure 1, the watch body 2 is generally disc-shaped. To facilitate the description of the following embodiments, an XYZ coordinate system is established for the watch body 2 described in this embodiment and the following embodiments. Specifically, the thickness direction of the watch body 2 is defined as the Z-axis, and the plane perpendicular to the Z-axis is defined as the XY plane. The location on the watch body 2 for connecting to the first strap portion 11 is defined as first location A, and the location on the watch body 2 for connecting to the second strap portion 12 is defined as second location B. First location A and second location B are located within the XY plane. Based on this, the direction of alignment of first location A and second location B is defined as the X-axis, and the direction perpendicular to the X-axis within the XY plane is defined as the Y-axis. It is understood that the coordinate system configuration of the watch body 2 can be flexibly configured based on practical needs and is not specifically limited here. In other embodiments, the watch body 2 may also be generally disc-shaped, such as an elliptical disc, a triangular disc, a polygonal disc, or a rectangular disc, which are not specifically limited here.

[0064] Please refer to Figures 1 and 2 together. Figure 2 is an exploded view of the watch body 2 in the electronic device 100 shown in Figure 1. The watch body 2 includes a watch body 21, a screen 22, an upper case 23, a lower case 24, a circuit board assembly 25, a battery (not shown), and a photoplethysmograph 26.

[0065] It is understood that Figures 1 and 2 schematically illustrate some components included in the watch body 2, and the actual shape, actual size, actual position and actual structure of these components are not limited by Figures 1 and 2. In some other embodiments, the watch body 2 may also not include the screen 22.

[0066] The watch body 21 is the support frame of the watch body 2, and the first position A and the second position B are located on the watch body 21. The material of the watch body 21 can be stainless steel to ensure the structural strength of the watch body 21 and the support strength for other components.

[0067] The upper case 23 is connected to one end of the watch body 21 along the Z axis, and the lower case 24 is connected to the other end of the watch body 21 along the Z axis. The materials of the upper case 23 and the lower case 24 include, but are not limited to, metal materials such as stainless steel, and plastics such as polycarbonate (PC), PC + fiberglass, and ABS (acrylonitrile butadiene styrene plastic).

[0068] The upper case 23, the body 21, and the lower case 24 form the housing of the watch body 2, with the lower case 24 forming the back cover. The interior of the housing forms a housing space, which houses the circuit board assembly 25 and a battery. The battery is used to power the circuit board assembly 25.

[0069] The screen 22 is fixed to the upper case 23. The screen 22 is used to display hour hand, minute hand, second hand, dial, digital time, weather, temperature, electrocardiogram (ECG), human body temperature, heart rate, body fat, voltage and other numerical values ​​or graphics.

[0070] The photoplethysmograph 26 uses PPG technology to detect changes in the wearer's heart rate. Please refer to Figures 2 and 3 . Figure 3 is a schematic cross-sectional view of the electronic device 100 shown in Figure 1 along line CC. The photoplethysmograph 26 includes a cover 261, a light transmitter 262, a light receiver 263, and a circuit board 264.

[0071] The cover plate 261 is used to protect the light emitter 262 and the light receiver 263. The cover plate 261 is provided on the lower case 24.

[0072] In some embodiments, referring to FIG. 4 , which is an enlarged view of region I of the electronic device 100 shown in FIG. 3 , the lower housing 24 is provided with a first light hole 24a and a second light hole 24b. The first light hole 24a allows the light beam emitted by the light emitter 262 to pass through and enter the outer side of the lower housing 24, while the second light hole 24b allows the light beam from the outer side of the lower housing 24 to pass through and enter the light receiver 263. The shapes of the first light hole 24a and the second light hole 24b can be circular, rectangular, polygonal, or other irregular shapes. It should be noted that in the above embodiment and the following embodiments, the term "outer side" used in describing the "lower housing 24" refers to the side of the lower housing 24 facing away from the aforementioned accommodating space, the term "outer surface" refers to the surface of the lower housing 24 facing away from the aforementioned accommodating space, and the term "inner side" refers to the side of the lower housing 24 facing the aforementioned accommodating space. These terms will not be explained in detail below.

[0073] On the basis of the above, the cover plate 261 is arranged on the outer surface of the lower case 24 and covers the first light hole 24a and the second light hole 24b.

[0074] In this way, a retaining wall is formed by the portion of the lower case 24 located between the first light hole 24a and the second light hole 24b to separate the light emitted by the light emitter 262 and the light received by the light receiver 263, thereby reducing light crosstalk between the light emitter 262 and the light receiver 263.

[0075] In other embodiments, the lower case 24 may be provided with an opening, with the cover plate 261 covering the opening. Alternatively, a portion of the lower case 24 may form the cover plate 261. This eliminates any overlap between the cover plate 261 and the lower case 24 in the Z-axis direction, thus reducing the height of the watch body 2 in the Z-axis direction.

[0076] Continuing with Figure 4, the cover plate 261 includes a first light-transmitting portion 261a and a second light-transmitting portion 261b. The first light-transmitting portion 261a covers the first light-through hole 24a, and the second light-transmitting portion 261b covers the second light-through hole 24b. The first light-transmitting portion 261a allows the light beam emitted by the light emitter 262 to pass through and enter the outside of the cover plate 261, while the second light-transmitting portion 261b allows the light beam outside the cover plate 261 to pass through and enter the light receiver 263. It should be noted that in the above embodiment and the following embodiments, the "outer side" used in describing the "cover plate 261" refers to the side of the cover plate 261 facing away from the aforementioned accommodating space, the "outer surface" used in describing the "cover plate 261" refers to the surface of the cover plate 261 facing away from the aforementioned accommodating space, and the "inner side" used in describing the cover plate 261 facing away from the aforementioned accommodating space. These terms will not be explained in detail below.

[0077] The remaining portion of the cover plate 261, excluding the first light-transmitting portion 261a and the second light-transmitting portion 261b, may be a light-transmitting structure, an opaque structure, or a partially light-transmitting structure and a partially opaque structure. The embodiment shown in FIG4 is illustrative of the embodiment in which the remaining portion is light-transmitting, and this is not to be construed as a special limitation of the present application.

[0078] In the above embodiment, the present application does not limit the specific material of the cover plate 261, as long as it meets the light transmission requirements of the light emitter 262 and the light receiver 263. The material of the cover plate 261 is sapphire or ultra-clear glass. Sapphire and ultra-clear glass have good light transmittance and high strength, ensuring both light transmittance and impact resistance.

[0079] Referring back to Figure 3 , the light emitter 262, light receiver 263, circuit board 264, and optical lens 265 are all located inside the cover 261. Furthermore, the light emitter 262, light receiver 263, and circuit board 264 are also located inside the lower case 24. The circuit board 264 is located on the side of the light emitter 262 and light receiver 263 that faces away from the cover 261. The light emitter 262 and light receiver 263 are supported on and electrically connected to the circuit board 264. The circuit board 264 is electrically connected to the circuit board assembly 25.

[0080] The light emitter 262 has a light-emitting surface, which faces the first light-transmitting portion 261a. The light receiver 263 has a light-incident surface, which faces the second light-transmitting portion 261b. The light emitter 262 is used to emit light outward via the light-emitting surface, and the light receiver 263 is used to receive external light signals via the light-incident surface.

[0081] The light emitter 262 may include one lamp bead or may include multiple lamp beads arranged in an array, which is not specifically limited here. When the light emitter 262 includes one lamp bead, the center O1 of the light emitting surface of the light emitter 262 described below refers to the center of the light emitting surface of the one lamp bead; when the light emitter 262 includes multiple lamp beads arranged in an array, the center O1 of the light emitting surface of the light emitter 262 described below refers to the array center of the light emitting surfaces of the multiple lamp beads. For example, please refer to Figure 5, which is a bottom view of the light emitter 262 and the light receiver 263 in the electronic device 100 shown in Figure 4. The light emitter 262 includes two lamp beads 262a. The center O1 of the light emitting surface of the light emitter 262 is the array center of the light emitting surfaces of the two lamp beads 262a.

[0082] The present embodiment does not limit the specific structures of the lamp bead in the light emitter 262 and the light receiver 263. For example, the lamp bead in the light emitter 262 can be a light emitting diode (LED), and the light receiver 263 can be a photodiode (PD).

[0083] The light emitted by the lamp beads in the light emitter 262 can be visible light, such as green light. In other embodiments, the light emitted by the lamp beads in the light emitter 262 can also be red light or blue light, etc., which is not specifically limited here.

[0084] The number of light receivers 263 can be one or more. "More" means two or more. On this basis, the number of second light-transmitting portions 261b and the number of second light-through holes 24b can be equal to the number of light receivers 263, and correspond one to one.

[0085] In the embodiment shown in FIG. 2 to FIG. 5 , there are two light receivers 263 , and the two light receivers 263 are located on opposite sides of the light transmitter 262 .

[0086] Based on the above, please refer to Figure 6, which is a top view of the inner cover 261 of the electronic device 100 shown in Figure 4. The first light-transmitting portion 261a is generally rectangular in shape and faces the light-emitting surface of the light emitter 262. There are two second light-transmitting portions 261b, each also generally rectangular in shape, facing the light-incident surfaces of the two light receivers 263. In other embodiments, the first light-transmitting portion 261a and the second light-transmitting portion 261b may also be circular, polygonal, or other irregular shapes.

[0087] Please refer to Figure 7, which is a schematic diagram of the structure of the electronic device 100 shown in Figure 4 when worn on a user's wrist. When the photoplethysmograph 26 is in operation, light L1 emitted from the light-emitting surface of the light emitter 262 passes through the first light-transmitting portion 261a and enters the wrist. This light is absorbed by the blood and tissue in the wrist and partially reflected, forming reflected light L2. Reflected light L2 then passes through the second light-transmitting portion 261b and enters the light-incident surface of the light receiver 263, thereby receiving the optical signal.

[0088] When light emitted by light emitter 262 reaches cover plate 261, it is reflected off the surface of cover plate 261 facing light emitter 262 and the surface facing away from light emitter 262 due to the different refractive indices between cover plate 261 and air. The greater the angle of incidence, the stronger the reflected light. Because the light emitted by light emitter 262 is a divergent beam, not a parallel beam, and because the surfaces of cover plate 261 facing light emitter 262 and the surfaces facing away from light emitter 262 are both approximately planar, cover plate 261 has a high reflectivity for the light emitted by light emitter 262. This results in low light extraction efficiency, and less light enters the human body. Furthermore, the large angle of light emitted by cover plate 261 results in a low maximum light intensity entering the human body. This, in turn, affects detection accuracy and blood perfusion index.

[0089] In order to solve the above problem, please refer back to FIG. 2 to FIG. 4 . The photoplethysmograph 26 further includes an optical lens 265 . The optical lens 265 is disposed on the surface of the first light-transmitting portion 261 a facing the light emitter 262 .

[0090] Specifically, the optical lens 265 can be disposed on a portion of the surface of the first light-transmitting portion 261a facing the light emitter 262, or can be disposed on the entire surface of the first light-transmitting portion 261a facing the light emitter 262. Please refer specifically to FIG6 . This embodiment is described by exemplifying that the optical lens 265 is disposed on the entire surface of the first light-transmitting portion 261a facing the light emitter 262, and this is not to be considered a special limitation of the present application.

[0091] The material of the optical lens 265 may include at least one of glass, sapphire, polyamide, polycarbonate, polymeric methyl methacrylate (PMMA), thermoplastic polyurethanes (TPU), and transparent nylon.

[0092] The optical lens 265 can be glued and fixed to the surface of the first light-transmitting portion 261a facing the light emitter 262, or can be integrally formed with the first light-transmitting portion 261a, that is, the optical lens 265 and the first light-transmitting portion 261a are an integral structural component.

[0093] Specifically, when the optical lens 265 is made of polyamide, polycarbonate, polymethyl methacrylate, thermoplastic polyurethane elastomer rubber, or transparent nylon, the optical lens 265 can be formed on the first light-transmitting portion 261a using an integral injection molding process (e.g., a two-color injection molding process). Specifically, the injection molding process includes stages such as mold closing, filling, pressure holding, cooling, mold opening, and demolding.

[0094] In this way, there is no other medium between the optical lens 265 and the first light-transmitting portion 261a, which can ensure the light extraction efficiency and isolate the light from leaking between the optical lens 265 and the first light-transmitting portion 261a. In addition, no attachment operation is required, which reduces the process difficulty.

[0095] The optical lens 265 is used to adjust the angle of incidence of the light emitted by the light emitter 262 on the surface of the cover plate 261 facing the light emitter 262 and the surface facing away from the light emitter 262, thereby reducing the reflectivity and increasing the light energy incident on the human body. At the same time, the optical lens 265 is also used to reduce the light emission angle of the light emitted by the light emitter 262 when it is emitted from the cover plate 261, thereby increasing the maximum light intensity incident on the human body. This improves measurement accuracy and blood perfusion index. At the same time, because the optical lens 265 is provided on the surface of the first light-transmitting portion 261a facing the light emitter 262, the optical lens 265 is not visible to the user of the electronic device, thereby ensuring the aesthetics of the electronic device.

[0096] The structure of the optical lens 265 will be described in detail below.

[0097] Please refer to FIG8 , which is an enlarged view of the optical lens 265 in the electronic device 100 shown in FIG1 to FIG4 . The optical lens 265 includes a light-transmitting substrate 2651 and a microlens array 2652 .

[0098] The light-transmitting substrate 2651 has a first surface S1 and a second surface S2 that oppose each other. Both the first surface S1 and the second surface S2 are planar and substantially parallel to each other. When the optical lens 265 is used in the photoplethysmograph 26, the first surface S1 faces the light emitter 262, and the second surface S2 faces the first light-transmitting portion 261a.

[0099] The thickness h of the transparent substrate 2651 is the distance from the first surface S1 to the second surface S2. In some embodiments, the thickness h of the transparent substrate 2651 can be greater than or equal to 100 nanometers (nm) and less than or equal to 400 nm. Specifically, the thickness h of the transparent substrate 2651 can be 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, or 400 nm. In this way, the thickness h of the transparent substrate 2651 is moderate, capable of supporting the microlens array 2652, while absorbing less light and ensuring light extraction efficiency.

[0100] The microlens array 2652 is disposed on the first surface S1. Please refer to FIG. 9 , which is a schematic diagram of the structure of the optical lens 265 shown in FIG. 8 on the first surface S1. The microlens array 2652 can be distributed over the entire area of ​​the first surface S1, or can be disposed in a partial area of ​​the first surface S1. This application is exemplified by the case where the microlens array 2652 is distributed over the entire area of ​​the first surface S1. The microlens array 2652 includes a plurality of microlenses arranged in an array, each of which is a convex sphere protruding from the first surface S1 in a direction away from the second surface S2.

[0101] The convex sphere can converge the light beam and reduce the incident angle of some light on the surface of the cover plate 261 facing the light emitter 262 and the surface of the cover plate 261 facing away from the light emitter 262, thereby reducing the amount of light reflected by the cover plate 261. Moreover, the convex sphere can converge the light beam and reduce the light output angle after the light is emitted from the cover plate 261. However, since the microlens is located in the light path, it will inevitably absorb some light, which can easily cause energy loss. If the array of microlenses is not designed properly, the light output efficiency will be reduced, the light energy and maximum light intensity entering the human body will be reduced, and the measurement accuracy and blood perfusion index will be reduced.

[0102] Therefore, the following focuses on the array form of microlenses.

[0103] Continuing with FIG9 , the microlens array 2652 includes a first microlens group 2652a and multiple second microlens group arrays Ar1. In the embodiment shown in FIG9 , the number of second microlens group arrays Ar1 is seven. In other embodiments, the number of second microlens group arrays Ar1 may also be three, four, five, six, etc., without specific limitation herein.

[0104] Each second microlens group array Ar1 includes a plurality of second microlens groups 2652b arranged in an array around the first microlens group 2652a. The plurality of second microlens group arrays Ar1 are sequentially arranged along the radial direction of the annular array track of the plurality of second microlens groups 2652b.

[0105] The structures of the first microlens group 2652a and the second microlens group 2652b can be the same or different. The following embodiments are described on the basis that the structures of the first microlens group 2652a and the second microlens group 2652b are the same, which is not to be considered as a special limitation of the present application.

[0106] Based on the above, please refer to Figure 10, which is a schematic diagram of the structure of the first microlens group 2652a or the second microlens group 2652b in the microlens array within the optical lens 265 shown in Figure 9. The first microlens group 2652a and the second microlens group 2652b both include a first microlens unit C1 and a second microlens array Ar2.

[0107] The first microlens unit C1 includes at least one first microlens T1. "At least one" refers to one or more than one. In the embodiment shown in FIG10 , the number of first microlens T1 in the first microlens unit C1 is one. In other embodiments, the number of first microlenses T1 in the first microlens unit C1 may also be multiple, with "multiple" referring to two or more than two.

[0108] The second microlens array Ar2 includes a plurality of second microlenses T2 arranged in an array surrounding the first microlens units C1. In the embodiment shown in FIG10 , the number of second microlenses T2 in the second microlens array Ar2 is six. In other embodiments, the number of second microlenses T2 may be four, five, eight, ten, twelve, etc., without specific limitation herein.

[0109] In the above embodiment, both the first microlens T1 and the second microlens T2 are convex spheres that protrude from the first surface S1 toward a direction away from the second surface S2 .

[0110] The array mode of this microlens array can use the first microlens T1 and the second microlens T2 to converge the light beam emitted by the light emitter 262, reduce the incident angle of some light on the surface of the cover plate 261 facing the light emitter 262, and the surface of the cover plate 261 facing away from the light emitter 262, thereby reducing the amount of light reflected by the cover plate 261. Moreover, by using the first microlens T1 and the second microlens T2 to converge the light beam emitted by the light emitter 262, the light output angle after the light is emitted from the cover plate 261 can be reduced. At the same time, there is a certain gap between two adjacent second microlens group arrays Ar1, such as the gap g1 in Figure 9. These gaps are not provided with convex spheres, which can reduce the energy loss of light when passing through the microlens array. This is conducive to improving the light extraction efficiency, increasing the light energy and maximum light intensity entering the human body, and improving measurement accuracy and blood perfusion index.

[0111] At the same time, the microlens array 2652 occupies a relatively small height, making it easy to install in electronic devices with limited space.

[0112] In the above embodiment, optionally referring back to FIG. 9 , two adjacent second microlens group arrays Ar1 are spaced apart and closely arranged radially along the annular array trajectory of the plurality of second microlens groups 2652b. That is, the two adjacent second microlens group arrays Ar1 are spaced apart and closely arranged radially along the annular array trajectory of the plurality of second microlens groups 2652b.

[0113] The radial spacing between two adjacent second microlens group arrays Ar1 along the annular array trajectory of the plurality of second microlens groups 2652b means that the radial spacing between the two adjacent second microlens group arrays Ar1 along the annular array trajectory of the plurality of second microlens groups 2652b is greater than or equal to 0. In other words, of the two adjacent second microlens group arrays Ar1, the inner diameter of the outer second microlens group array Ar1 is greater than or equal to the outer diameter of the inner second microlens group array Ar1.

[0114] It should be noted that the outer diameter of the second microlens group array Ar1 refers to the diameter of the outer contour of the circle formed by connecting the points on the plurality of second microlens groups 2652b in the second microlens group array Ar1 that are farthest from the center of the circular array trajectory of the plurality of second microlens groups 2652b. Correspondingly, the inner diameter of the second microlens group array Ar1 refers to the diameter of the inner contour of the circle formed by connecting the points on the plurality of second microlens groups 2652b in the second microlens group array Ar1 that are closest to the center of the circular array trajectory of the plurality of second microlens groups 2652b.

[0115] For example, please refer to Figure 11, which is a schematic diagram of the structure of a second microlens array Ar1 within the optical lens 265 shown in Figure 9. The second microlens array Ar1 refers to the diameter D1 of the circular outer contour N1 formed by connecting the points on the plurality of second microlens groups 2652b in the second microlens array Ar1 that are farthest from the center of the circular array trajectory of the plurality of second microlens groups 2652b. Correspondingly, the inner diameter of the second microlens array Ar1 refers to the diameter D2 of the circular inner contour N2 formed by connecting the points on the plurality of second microlens groups 2652b in the second microlens array Ar1 that are closest to the center of the circular array trajectory of the plurality of second microlens groups 2652b. The inner and outer diameters of the second microlens array Ar1 described in the following embodiments should be understood in the same way and will not be further described.

[0116] In addition, the close arrangement of two adjacent second microlens group arrays Ar1 along the radial direction of the annular array trajectory of the plurality of second microlens groups 2652b means that, in the two adjacent second microlens group arrays Ar1, after one second microlens group 2652b is removed from the outer second microlens group array Ar1, while maintaining the spacing between the two adjacent second microlens groups 2652b unchanged, the inner diameter of a new array formed by arranging the remaining second microlens groups 2652b along the annular array is smaller than the outer diameter of the second microlens group array Ar1.

[0117] For example, please refer to Figure 12, which is a schematic diagram of the structure of two adjacent second microlens group arrays Ar1 within the optical lens 265 shown in Figure 9. Specifically, the outer second microlens group array is labeled Ar11, and the inner second microlens group array is labeled Ar12. The number of second microlens groups 2652b within the outer second microlens group array Ar11 is nineteen, and the outer diameter of the inner second microlens group array Ar12 is D11. After removing one second microlens group 2652b from the outer second microlens group array Ar11, eighteen second microlens groups 2652b remain. The new array formed by arranging these eighteen second microlens groups 2652b along a circular array is shown in Figure 13. The spacing d2 between two adjacent second microlens groups 2652b in this new array is equal to the spacing d1 between two adjacent second microlens groups 2652b within the outer second microlens group array Ar11 shown in Figure 12. Here, "equal" should be understood as approximately equal. When the difference between the two is less than or equal to 0.01 mm, they are considered equal. The inner diameter of the new array shown in Figure 13 is D3. D3 is smaller than the outer diameter D11 of the inner second microlens array Ar12. In other words, the outer second microlens array Ar11 is as close as possible to the inner second microlens array Ar12.

[0118] At the same time, referring back to FIG9 , the first microlens group 2652a and the adjacent second microlens group array Ar1 are also spaced apart and closely arranged radially along the annular array trajectory of the plurality of second microlens groups 2652b. That is, the first microlens group 2652a and the adjacent second microlens group array Ar1 are spaced apart and closely arranged radially along the annular array trajectory of the plurality of second microlens groups 2652b. At the same time, the first microlens group 2652a and the adjacent second microlens group array Ar1 are closely arranged radially along the annular array trajectory of the plurality of second microlens groups 2652b.

[0119] The “adjacent second microlens group array Ar1 ” refers to a second microlens group array Ar1 that is closest to the first microlens group 2652 a .

[0120] Furthermore, the radial spacing between the first microlens group 2652a and the adjacent second microlens group array Ar1 along the annular array trajectory of the plurality of second microlens groups 2652b means that the radial spacing between the first microlens group 2652a and the adjacent second microlens group array Ar1 along the annular array trajectory of the plurality of second microlens groups 2652b is greater than or equal to 0. In other words, the inner diameter of the adjacent second microlens group array Ar1 is greater than or equal to the outer diameter of the first microlens group 2652a.

[0121] Furthermore, the close radial arrangement of the first microlens group 2652a and the adjacent second microlens group array Ar1 along the annular array trajectory of the plurality of second microlens groups 2652b means that after one second microlens group 2652b is removed from the adjacent second microlens group array Ar1, while maintaining the spacing between two adjacent second microlens groups 2652b unchanged, the inner diameter of the new array formed by arranging the remaining second microlens groups 2652b along the annular array is smaller than the outer diameter of the first microlens group 2652a.

[0122] In this way, the number of second microlens arrays Ar1 arranged on the first surface S1 is relatively large. This can converge the light beam emitted by the light emitter 262 as much as possible, reducing the angle of incidence of some light on the surface of the cover plate 261 facing the light emitter 262 and the surface of the cover plate 261 facing away from the light emitter 262, thereby reducing the amount of light reflected by the cover plate 261. Furthermore, it can converge the light beam emitted by the light emitter 262 as much as possible, reducing the light output angle after the light is emitted from the cover plate 261. This can improve light extraction efficiency, increase the light energy and maximum light intensity entering the human body, and improve measurement accuracy and blood perfusion index.

[0123] In addition, in some embodiments, referring back to FIG. 9 , in each second microlens group array Ar1, the plurality of second microlens groups 2652b are spaced apart and closely arranged along the annular array trajectory of the plurality of second microlens groups 2652b. In other words, in each second microlens group array Ar1, the plurality of second microlens groups 2652b are spaced apart and closely arranged along the annular array trajectory of the plurality of second microlens groups 2652b.

[0124] The plurality of second microlens groups 2652b being spaced apart along the annular array track of the plurality of second microlens groups 2652b means that, in the plurality of second microlens groups 2652b, the spacing between two adjacent second microlens groups 2652b along the annular array track of the plurality of second microlens groups 2652b is greater than or equal to 0. In this way, there is no overlap between two adjacent second microlens groups 2652b. The plurality of second microlens groups 2652b being closely spaced along the annular array track of the plurality of second microlens groups 2652b means that, in the plurality of second microlens groups 2652b, the sum of the spacing between two adjacent second microlens groups 2652b along the annular array track of the plurality of second microlens groups 2652b is less than the width of a single second microlens group 2652b along the annular array track of the plurality of second microlens groups 2652b.

[0125] For example, please refer to Figure 14, which is a schematic diagram of the structure of a second microlens group array Ar1 within the optical lens 265 shown in Figure 9. The number of second microlens groups 2652b in the second microlens group array Ar1 is nineteen. Assume that the spacing between two adjacent second microlens groups 2652b along the annular array trajectory of the second microlens group array Ar1 is d1, and d1 ≥ 0 mm. Nineteen spacings d1 are formed between the nineteen second microlens groups 2652b, and the sum of these nineteen spacings d1 is approximately 19 × d1. Based on this, and continuing with Figure 14, assume that the width of a single second microlens group 2652b along the annular array trajectory of the second microlens group array Ar1 is w1. Then, 19 × d1 < w1. In other words, if the diameter of the annular array trajectory of the second microlens group array Ar1 is constant, the number of second microlens groups 2652b in the second microlens group array Ar1 has reached saturation, and no additional second microlens groups 2652b can be added.

[0126] In this way, a large number of second microlens groups 2652b are arranged within each second microlens group array Ar1. This can maximize the convergence of the light beam emitted by the light emitter 262, reducing the angle of incidence of some light on the surface of the cover plate 261 facing the light emitter 262 and the surface of the cover plate 261 facing away from the light emitter 262, thereby reducing the amount of light reflected by the cover plate 261. Furthermore, it can maximize the convergence of the light beam emitted by the light emitter 262, reducing the light output angle after the light is emitted from the cover plate 261. This can improve light extraction efficiency, increase the light energy and maximum light intensity entering the human body, and enhance measurement accuracy and blood perfusion index.

[0127] Furthermore, in some embodiments, referring back to FIG. 10 , within the first microlens group 2652a and the second microlens group 2652b, the second microlens array Ar2 and the first microlens unit C1 are spaced apart and closely arranged radially along the annular array trajectory of the plurality of second microlenses T2. That is, the second microlens array Ar2 and the first microlens unit C1 are spaced apart and closely arranged radially along the annular array trajectory of the plurality of second microlenses T2.

[0128] The second microlens array Ar2 and the first microlens unit C1 are arranged radially spaced apart along the annular array trajectory of the plurality of second microlenses T2, which means that the radial spacing between the second microlens array Ar2 and the first microlens unit C1 along the annular array trajectory of the plurality of second microlenses T2 is greater than or equal to 0. In other words, the inner diameter of the second microlens array Ar2 is greater than or equal to the maximum width of the first microlens unit C1.

[0129] It should be noted that the inner diameter of the second microlens array Ar2 refers to the diameter of the inner contour of the circle formed by connecting the points on the second microlenses T2 in the second microlens array Ar2 that are closest to the center of the annular array trajectory of the second microlenses T2.

[0130] Based on the above, it should be noted that the maximum width of the first microlens unit C1 refers to the maximum width of the area occupied by the first microlens unit C1 on the first surface S1. When there is only one first microlens T1 in the first microlens unit C1, the maximum width is the diameter of the area occupied by the first microlens T1 on the first surface S1. When there are multiple first microlenses T1 in the first microlens unit C1 and they are arranged in a row, the maximum width is the sum of the diameters of the areas occupied by the multiple first microlenses T1 on the first surface S1 and the distance between two adjacent first microlenses T1.

[0131] Furthermore, the close radial arrangement of the second microlens array Ar2 and the first microlens unit C1 along the annular array trajectory of the plurality of second microlenses T2 means that, after removing one second microlens T2 from the second microlens array Ar2, while maintaining the spacing between two adjacent second microlenses T2 unchanged, the inner diameter of the new array formed by arranging the remaining second microlenses T2 along the annular array is smaller than the maximum occupied width of the first microlens unit C1. In other words, the distance between the second microlens array Ar2 and the first microlens unit C1 is as close as possible.

[0132] In this way, the first microlens group 2652a and the second microlens group 2652b occupy a smaller area on the first surface S1, and a larger number of first microlens groups 2652a and second microlens groups 2652b can be arranged on the first surface S1. This can converge the light beam emitted by the light emitter 262 as much as possible, reducing the angle of incidence of some light on the surface of the cover plate 261 facing the light emitter 262 and the surface of the cover plate 261 facing away from the light emitter 262, thereby reducing the amount of light reflected by the cover plate 261. Moreover, it can converge the light beam emitted by the light emitter 262 as much as possible, reducing the light output angle after the light is emitted from the cover plate 261. This can improve light extraction efficiency, increase the light energy and maximum light intensity entering the human body, and improve measurement accuracy and blood perfusion index.

[0133] Furthermore, in some embodiments, referring back to FIG. 10 , the plurality of second microlenses T2 in the second microlens array Ar2 are also spaced apart and closely arranged along the annular array trajectory of the plurality of second microlenses T2. In other words, in the second microlens array Ar2, the plurality of second microlenses T2 are spaced apart and closely arranged along the annular array trajectory of the plurality of second microlenses T2.

[0134] The plurality of second microlenses T2 being arranged at intervals along the annular array track of the plurality of second microlenses T2 means that the spacing between two adjacent second microlenses T2 along the annular array track of the plurality of second microlenses T2 is greater than or equal to 0. In this way, there is no overlap between two adjacent second microlenses T2.

[0135] Furthermore, the multiple second microlenses T2 being closely arranged along the annular array track of the multiple second microlenses T2 means that: within the multiple second microlenses T2, the sum of the spacings d3 between two adjacent second microlenses T2 along the annular array track of the multiple second microlenses T2 is less than the width w2 of a single second microlens T2 along the annular array track (i.e., the diameter of the area occupied by the second microlens T2 on the first surface S1). In other words, if the diameter of the annular array track of the second microlens array Ar2 is constant, the number of second microlenses T2 within the second microlens array Ar2 has reached saturation, and no additional second microlenses T2 can be added.

[0136] In this way, the second microlens array Ar2 includes a larger number of second microlenses T2. This allows the light beam emitted by the light emitter 262 to be converged as much as possible, reducing the angle of incidence of some light on the surface of the cover plate 261 facing the light emitter 262 and the surface of the cover plate 261 facing away from the light emitter 262, thereby reducing the amount of light reflected by the cover plate 261. Furthermore, the light beam emitted by the light emitter 262 can be converged as much as possible, reducing the light output angle after being emitted from the cover plate 261. This improves light extraction efficiency, increases the light energy and maximum light intensity incident on the human body, and enhances measurement accuracy and blood perfusion index.

[0137] The structures of the first microlens group 2652a and the second microlens group 2652b in the optical lens 265 provided by an embodiment of the present application are described above using FIG. 10 as an example. Two other embodiments of the first microlens group 2652a and the second microlens group 2652b are described below.

[0138] Specifically, please refer to Figures 15 and 16. Figure 15 is a schematic diagram of the structure of an optical lens 265 provided in some other embodiments of the present application on the first surface S1, and Figure 16 is a schematic diagram of the structure of a first microlens group 2652a or a second microlens group 2652b in the microlens array within the optical lens 265 shown in Figure 15. The first microlens group 2652a and the second microlens group 2652b shown in this embodiment differ from the first microlens group 2652a and the second microlens group 2652b shown in Figure 8 in that: in this embodiment, the number of first microlenses T1 within the first microlens unit C1 is multiple. Specifically, in the embodiment shown in Figure 16, the number of first microlenses T1 within the first microlens unit C1 is two. In other embodiments, the number of first microlenses T1 within the first microlens unit C1 may also be three, four, five, etc., without specific limitation herein. The multiple first microlenses T1 are arranged in a row. Furthermore, referring specifically to Figure 15 , the arrangement direction of the multiple first microlenses T1 within the second microlens group 2652b is aligned with the extension direction of the annular array trajectory of the second microlens group array Ar1 in which the second microlens group 2652b is located. "Aligned" should be understood as substantially aligned; two directions are considered aligned if the angle between them is less than or equal to 5°. This facilitates the positioning of the multiple first microlenses T1 within the first surface S1, reducing design complexity.

[0139] In the above embodiment, optionally, within the first microlens unit C1, the plurality of first microlenses T1 are spaced apart and closely arranged. That is, within the first microlens unit C1, the plurality of first microlenses T1 are spaced apart and closely arranged.

[0140] The plurality of first microlenses T1 being arranged at intervals means that the spacing d4 between two adjacent first microlenses T1 is greater than or equal to 0. Furthermore, the plurality of first microlenses T1 being arranged closely means that the spacing d4 between two adjacent first microlenses T1 is less than or equal to 0.003 millimeters (mm). Specifically, the spacing d4 can be 0.001 mm, 0.002 mm, or 0.003 mm.

[0141] As a result, the first microlens unit C1 occupies a smaller area on the first surface S1, which helps reduce the area occupied by the first microlens group 2652a and the second microlens group 2652b on the first surface S1, allowing a larger number of first microlens groups 2652a and second microlens groups 2652b to be arranged on the first surface S1. This effectively converges the light beam emitted by the light emitter 262, reducing the angle of incidence of some light on the surface of the cover plate 261 facing the light emitter 262 and the surface of the cover plate 261 facing away from the light emitter 262, thereby reducing the amount of light reflected by the cover plate 261. Furthermore, it effectively converges the light beam emitted by the light emitter 262, reducing the light output angle after the light is emitted from the cover plate 261. This improves light extraction efficiency, increases the light energy and maximum light intensity incident on the human body, and enhances measurement accuracy and blood perfusion index.

[0142] The first microlens group 2652a and the second microlens group 2652b shown in Figures 15 and 16 are similar to the first microlens group 2652a and the second microlens group 2652b shown in Figures 9 and 10 in that the second microlens array Ar2 and the first microlens unit C1 are spaced and closely arranged along the radial direction of the annular array trajectory of the plurality of second microlenses T2.

[0143] In this way, the first microlens group 2652a and the second microlens group 2652b occupy a smaller area on the first surface S1, and a larger number of first microlens groups 2652a and second microlens groups 2652b can be arranged on the first surface S1. This can converge the light beam emitted by the light emitter 262 as much as possible, reducing the angle of incidence of some light on the surface of the cover plate 261 facing the light emitter 262 and the surface of the cover plate 261 facing away from the light emitter 262, thereby reducing the amount of light reflected by the cover plate 261. Moreover, it can converge the light beam emitted by the light emitter 262 as much as possible, reducing the light output angle after the light is emitted from the cover plate 261. This can improve light extraction efficiency, increase the light energy and maximum light intensity entering the human body, and improve measurement accuracy and blood perfusion index.

[0144] The first and second microlens groups 2652a and 2652b shown in Figures 15 and 16 differ from the first and second microlens groups 2652a and 2652b shown in Figures 9 and 10 in another respect: in the optical lens 265 shown in Figures 15 and 16, the plurality of second microlenses T2 within the second microlens array Ar2 are arranged non-densely along the annular array trajectory of the plurality of second microlenses T2. Alternatively, referring specifically to Figure 16, the number of second microlenses T2 within the second microlens array Ar2 is six. This configuration reduces the number of second microlenses T2 within the second microlens array Ar2, thereby reducing the structural complexity and cost of the optical lens 265.

[0145] Please refer to Figures 17 and 18. Figure 17 is a schematic diagram of the structure of an optical lens 265 on the first surface S1 according to further embodiments of the present application. Figure 18 is a schematic diagram of the structure of a first microlens group 2652a or a second microlens group 2652b in the microlens array within the optical lens 265 shown in Figure 17. The first microlens group 2652a and the second microlens group 2652b shown in this embodiment differ from the first microlens group 2652a and the second microlens group 2652b shown in Figures 15 and 16 in that, in this embodiment, within the second microlens array Ar2, a plurality of second microlenses T2 are closely arranged along the annular array trajectory of the plurality of second microlenses T2. Specifically, the number of second microlenses T2 within the second microlens array Ar2 is twelve.

[0146] In this way, the second microlens array Ar2 includes a larger number of second microlenses T2. This allows the light beam emitted by the light emitter 262 to be converged as much as possible, reducing the angle of incidence of some light on the surface of the cover plate 261 facing the light emitter 262 and the surface of the cover plate 261 facing away from the light emitter 262, thereby reducing the amount of light reflected by the cover plate 261. Furthermore, the light beam emitted by the light emitter 262 can be converged as much as possible, reducing the light output angle after being emitted from the cover plate 261. This improves light extraction efficiency, increases the light energy and maximum light intensity incident on the human body, and enhances measurement accuracy and blood perfusion index.

[0147] In other embodiments, within the first microlens unit C1 , the plurality of first microlenses T1 may also be arranged in a triangle or a quadrilateral, etc., which is not specifically limited here.

[0148] In any of the above embodiments, the size of the first microlens T1 and the size of the second microlens T2 may be the same or different, and are not specifically limited herein.

[0149] In the embodiment shown in FIG. 10 , FIG. 16 or FIG. 18 , the size of the first microlens T1 is larger than the size of the second microlens T2 .

[0150] Alternatively, please refer to FIG. 19 , which is a side view of a structure consisting of a single first microlens T1 and a transparent substrate 2651 in the first microlens group 2652a or the second microlens group 2652b shown in FIG. 10 , FIG. 16 , or FIG. 18 . The diameter D01 of the area occupied by the first microlens T1 on the first surface S1 is greater than or equal to 0.1 mm and less than or equal to 0.15 mm. Specifically, the diameter D01 can be 0.1 mm, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm, or 0.15 mm. The curvature of the end n1 of the first microlens T1 away from the first surface S1 is 0 mm. -1 The curvature of the end n2 of the first microlens T1 connected to the first surface S1 is greater than or equal to 8 mm. -1 and less than or equal to 10mm -1 Specifically, the curvature of the end n2 of the first microlens T1 connected to the first surface S1 can be 8mm -1 , 9mm -1 or 10mm -1 A height H01 of the first microlens T1 protruding from the first surface S1 is greater than or equal to 0.0252 mm and less than or equal to 0.034 mm. Specifically, the height H01 may be 0.0252 mm, 0.026 mm, 0.027 mm, 0.028 mm, 0.029 mm, 0.030 mm, 0.031 mm, 0.032 mm, 0.033 mm, or 0.034 mm.

[0151] In this way, the first microlens T1 can effectively converge the light beam, reducing the incident angle of some light on the surface of the cover plate 261 facing the light emitter 262 and the surface of the cover plate 261 facing away from the light emitter 262, thereby reducing the amount of light reflected by the cover plate 261. Furthermore, the first microlens T1 can effectively converge the light beam and reduce the angle of light exiting the cover plate 261. This can increase the light energy and maximum light intensity incident on the human body, improving measurement accuracy and blood perfusion index.

[0152] Alternatively, please refer to Figure 20, which is a side view of the structure consisting of a single second microlens T2 and a transparent substrate 2651 in the first microlens group 2652a or the second microlens group 2652b shown in Figures 10, 16, or 18. The diameter D02 of the area occupied by the second microlens T2 on the first surface S1 is greater than or equal to 0.05 mm and less than or equal to 0.1 mm. Specifically, the diameter D02 can be 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, or 0.1 mm. The curvature of the end n3 of the second microlens T2 away from the first surface S1 is 0 mm. -1The curvature of the end of the second microlens T2 connected to the first surface S1 may be greater than or equal to 5 mm. -1 , and less than or equal to 40mm -1 Specifically, the curvature of the end n4 of the second microlens T2 connected to the first surface S1 can be 5mm -1 , 10mm -1 , 15mm -1 , 20mm -1 , 25mm -1 , 30mm -1 , 35mm -1 or 40mm -1 The height H02 of the second microlens T2 protruding from the first surface S1 is greater than or equal to 0.01 mm and less than or equal to 0.0175 mm. Specifically, the height H02 may be 0.01 mm, 0.011 mm, 0.012 mm, 0.013 mm, 0.014 mm, 0.015 mm, 0.016 mm, 0.017 mm, or 0.0175 mm.

[0153] In this way, the second microlens T2 can effectively converge the light beam, reducing the incident angle of some light on the surface of the cover plate 261 facing the light emitter 262 and the surface of the cover plate 261 facing away from the light emitter 262, thereby reducing the amount of light reflected by the cover plate 261. Furthermore, the second microlens T2 can effectively converge the light beam and reduce the angle of light exiting the cover plate 261. This can increase the light energy and maximum light intensity incident on the human body, improving measurement accuracy and blood perfusion index.

[0154] The microlens array, composed of a combination of first microlenses T1 and second microlenses T2 of varying sizes, effectively converges the light beam, minimizing light reflection from cover plate 261 and reducing the angle of light exiting from cover plate 261. Furthermore, the microlens array includes gaps, which are free of convex spheres, to minimize energy loss as light passes through the microlens array. This improves light extraction efficiency, increases the amount of light entering the body and its maximum intensity, and enhances measurement accuracy and blood perfusion index.

[0155] The above describes various structures of the optical lens 265. When the optical lens 265 is installed in the photoplethysmograph 26, the array center O2 (see FIG6 ) of the microlens array within the optical lens 265 is aligned with the center O1 of the light-emitting surface of the light emitter 262. The term "aligned" should be understood as approximately aligned. When the lateral distance between the array center O2 and the center O1 is less than or equal to 0.1 mm, the array center O2 and the center O1 are considered aligned.

[0156] In this way, the light emitted by the light emitter 262 is better converged, the amount of reflection of the light emitted by the light emitter 262 by the cover plate 261 can be reduced, and the light output angle of the light emitted by the cover plate 261 can be reduced.

[0157] To verify the performance of the optical lens 265 provided in the various embodiments described above, the optical lenses 265 shown in Figures 9, 15, and 17 were applied to the photoplethysmograph 26 described above, with the center of the microlens array within the optical lens 265 aligned approximately with the center of the light-emitting surface of the light emitter 262. Four performance indicators were obtained: light-emitting efficiency, light-emitting angle, maximum light intensity, and the blood perfusion index (first PI value and second PI value) detected by the two light receivers 263. These indicators are recorded in Table 1 below. The light-emitting angle refers to the angle of light emitted from the cover plate 261, and the maximum light intensity refers to the maximum light intensity incident on the human body. This maximum light intensity can be measured on the outer surface of the cover plate 261.

[0158] Specifically, the performance indicators of the optical lens 265 shown in Figure 9 are recorded in the "Example 1" row in Table 1, the performance indicators of the optical lens 265 shown in Figure 15 are recorded in the "Example 2" row in Table 1, and the performance indicators of the optical lens 265 shown in Figure 17 are recorded in the "Example 3" row in Table 1.

[0159] Moreover, taking the photoplethysmograph 26 without the optical lens 265 as a comparative solution, the obtained light output efficiency, light output angle, maximum light intensity and the blood perfusion index (first PI value and second PI value) detected by the two light receivers 263 are recorded in the "Comparative Example" row in Table 1.

[0160] Table 1

[0161] When evaluating the performance of the photoplethysmograph 26, among the four performance indicators of light output efficiency, light output angle, light output intensity, and blood perfusion index, the blood perfusion index should be given priority, followed by the light output angle and maximum light output intensity, and finally the light output efficiency. Therefore, it can be seen from Table 1 that compared with the "Comparative Example", in "Example 1", the blood perfusion index is increased by a maximum of 3.8%, and the first PI value and the second PI value are increased by an average of 1.203%. In "Example 2", the blood perfusion index is increased by a maximum of 2.47%, and the first PI value and the second PI value are increased by an average of 1.2036%. In "Example 3", the blood perfusion index is increased by a maximum of 5.28%, and the first PI value and the second PI value are increased by an average of 2.91%. Therefore, the optical lens 265 provided in the embodiment of the present application can improve the performance of the photoplethysmograph 26. The optical lens 265 provided in this application will not only not cause a significant decrease in the light emitting and receiving efficiency of the photoplethysmograph 26 , but will instead improve the blood perfusion index of the photoplethysmograph 26 , specifically by 1%-6%.

[0162] Please refer to Figure 21, which is a schematic diagram of the structure of a photoplethysmograph 26 within an electronic device 100 according to yet another embodiment of the present application. The photoplethysmograph 26 shown in this embodiment differs from the photoplethysmograph 26 shown in Figure 4 in that: In this embodiment, the cover 261 further includes a light-shielding portion 261c, which is opaque and located at least between the first light-transmitting portion 261a and the second light-transmitting portion 261b. This light-shielding portion 261c prevents some light emitted by the light emitter 262 from passing through the body part to be detected and directly entering the acquisition range of the light receiver 263, thereby preventing the detection accuracy of the photoplethysmograph 26 from being affected.

[0163] Based on the above embodiment, optionally, referring to FIG. 21 , the remaining portion of the cover plate 261, except for the first light-transmitting portion 261a and the second light-transmitting portion 261b, is formed as a light-shielding portion 261c. This light-shielding portion 261c minimizes the amount of light emitted by the light emitter 262 from passing directly into the collection range of the light receiver 263 without passing through the body part to be detected, thereby preventing the detection accuracy of the photoplethysmograph 26 from being affected.

[0164] In some embodiments, the light shielding portion 261c can be made of plastic. Specifically, the material of the light shielding portion 261c includes, but is not limited to, metal materials such as stainless steel, and plastics such as polycarbonate (PC), PC+glass fiber, and ABS plastic (acrylonitrile butadiene styrene plastic). The light shielding portion 261c and the lower case 24 form a structural unit, and the light shielding portion 261c is integrally formed with the first light-transmitting portion 261a and the second light-transmitting portion 261b. Specifically, the light shielding portion 261c and the lower case 24 can be formed on the first light-transmitting portion 261a and the second light-transmitting portion 261b using an injection molding process. In this way, the electronic device 100 includes fewer parts, which simplifies the assembly process.

[0165] In some embodiments, referring to FIG. 21 , a retaining wall 266 is further provided on the surface of the circuit board 264 facing the cover 261. The retaining wall 266 is located at least between the light emitter 262 and the light receiver 263. The retaining wall 266 also prevents some of the light emitted by the light emitter 262 from passing through the body part to be detected and directly entering the collection range of the light receiver 263, thereby preventing the detection accuracy of the photoplethysmograph 26 from being affected.

[0166] Please refer to FIG22 , which is a block diagram of a circuit board assembly 25 in an electronic device 100 according to some embodiments of the present application. The circuit board assembly 25 includes at least one processor 251 , a communication bus 252 , at least one communication interface 253 , and a memory 254 .

[0167] It is understood that FIG20 schematically illustrates some components included in the circuit board assembly 25. The circuit board assembly 25 may include more or fewer components than shown in FIG20, or may combine certain components, or may include different components. Although not shown, the circuit board assembly 25 may also include a Bluetooth module, a Global Positioning System (GPS) module, etc., which will not be described in detail here.

[0168] The processor 251 is communicatively connected to at least one communication interface 253, the memory 254, and the screen 22 via a communication bus 252. The processor 251 can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor. The processor is the control center of the electronic device 100, and uses various interfaces and lines to connect the various components of the entire electronic device 100.

[0169] The communication bus 252 may include a pathway for transmitting information between the aforementioned components.

[0170] The communication interface 253 uses any transceiver or other device for communicating with other devices or communication networks, such as Ethernet, radio access network (RAN), wireless local area network (WLAN), etc.

[0171] Memory 254 can be used to store computer programs and / or modules. Processor 251 implements the various functions of circuit board assembly 25 by running or executing the computer programs and / or modules stored in memory 254 and accessing data stored in memory 254. Memory 254 may primarily include a program storage area and a data storage area. The program storage area may store an operating system and application programs required for various functions (such as sound playback and image playback), while the data storage area may store data generated based on the use of circuit board assembly 25 (such as audio data and a phone book). Memory 254 may also include high-speed random access memory (RAM) and non-volatile memory, such as a hard drive, internal memory, a plug-in hard drive, a smart media card (SMC), a secure digital (SD) card, a flash card, multiple disk storage devices, flash memory devices, or other volatile solid-state storage devices. Memory 254 may be independent and connected to processor 251 via communication bus 252. Memory 254 may also be integrated with processor 251.

[0172] In a specific implementation, as an embodiment, the processor 251 may include one or more CPUs, such as CPU0 and CPU1 in the figure.

[0173] In a specific implementation, as an example, the circuit board assembly 25 may include multiple processors 251, such as CPU0 and CPU1 in FIG22 . Each of these processors may be a single-core (single-CPU) processor or a multi-core (multi-CPU) processor. The processor 251 herein may refer to one or more devices, circuits, and / or processing cores for processing data (e.g., computer program instructions).

[0174] In one embodiment of the present application, the processor 251 is electrically connected to the light emitter 262, the light receiver 263 and the screen 22, respectively. When the user triggers the photoplethysmograph to start working, the processor 251 controls the light emitter 262 to emit light outward. After the light is absorbed by the user's blood and tissue, part of it is reflected. The light receiver 263 can receive the reflected light after passing through the user's body, and convert the light signal into an electrical signal and send it to the processor 251. The processor 251 can determine changes in the wearer's heart rate and other conditions based on the reflected light received by the light receiver 263, and display it through the screen 22.

[0175] The above embodiments describe the application scenarios of the optical lens 265 on the photoplethysmograph 26. In other embodiments, the optical lens 265 can also be applied to the light-emitting side of a fill light of a camera or other device to converge the fill light source. Furthermore, the optical lens 265 can also be applied to the light-emitting side of an illumination light source of a projector or other device to converge the illumination light beam. This is not specifically limited here.

[0176] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0177] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An optical lens, characterized in that: include: a light-transmitting substrate having a first surface and a second surface opposite to each other; A microlens array, wherein the microlens array is arranged on the first surface, the microlens array includes a first microlens group and a plurality of second microlens group arrays, each of the second microlens group arrays includes a plurality of second microlens groups arranged around the first microlens group array, and the plurality of second microlens group arrays are sequentially arranged along the radial direction of the annular array trajectory of the plurality of second microlens groups, wherein: The first microlens group and the second microlens group each include a first microlens unit and a second microlens array, the first microlens unit includes at least one first microlens, and the second microlens array includes a plurality of second microlenses arranged around the first microlens unit array; The first microlens and the second microlens are both convex spheres protruding from the first surface toward a direction away from the second surface.

2. The optical lens according to claim 1, wherein Two adjacent second microlens group arrays are spaced apart and closely arranged along the radial direction of the annular array track of the plurality of second microlens groups, and the first microlens group and the adjacent second microlens group array are spaced apart and closely arranged along the radial direction of the annular array track of the plurality of second microlens groups.

3. The optical lens according to claim 1 or 2, characterized in that: In each second microlens group array, a plurality of second microlens groups are also spaced and closely arranged along the annular array track of the plurality of second microlens groups.

4. The optical lens according to any one of claims 1 to 3, characterized in that: The second microlens array and the first microlens unit are spaced apart and closely arranged along the radial direction of the annular array track of the plurality of second microlenses.

5. The optical lens according to any one of claims 1 to 4, characterized in that: In the second microlens array, the plurality of second microlenses are also spaced apart and closely arranged along the annular array track of the plurality of second microlenses.

6. The optical lens according to claim 5, wherein: In the first microlens unit, the number of the first microlens is one, and in the second microlens array, the number of the second microlenses is six.

7. The optical lens according to claim 4 or 5, characterized in that: In the first microlens unit, there are a plurality of first microlenses, the plurality of first microlenses are arranged in a row, and an arrangement direction of the plurality of first microlenses in the second microlens group is consistent with an extension direction of a circular array track of the second microlens group array in which the second microlens group is located.

8. The optical lens according to claim 7, wherein: In the first microlens group and the second microlens group, a plurality of the first microlenses are spaced apart and closely arranged.

9. The optical lens according to claim 8, wherein: In the first microlens group and the second microlens group, the number of the first microlenses is two, and in the second microlens array, the number of the second microlenses is twelve.

10. The optical lens according to claim 8, wherein In the first microlens group and the second microlens group, the number of the first microlenses is two, and in the second microlens array, the number of the second microlenses is six.

11. The optical lens according to any one of claims 1 to 10, characterized in that: The diameter of the area occupied by the first microlens on the first surface is greater than or equal to 0.1 mm and less than or equal to 0.15 mm, and the curvature of the end of the first microlens away from the first surface is 0 mm. -1 The curvature of one end of the first microlens connected to the first surface is greater than or equal to 8 mm -1 and less than or equal to 10mm -1 , a height of the first microlens protruding from the first surface is greater than or equal to 0.0252 mm and less than or equal to 0.034 mm.

12. The optical lens according to any one of claims 1 to 11, characterized in that: The diameter of the area occupied by the second microlens on the first surface is greater than or equal to 0.05 mm and less than or equal to 0.1 mm, and the curvature of the end of the second microlens away from the first surface is 0 mm. -1 The curvature of one end of the second microlens connected to the first surface is greater than or equal to 5 mm -1 and less than or equal to 40mm -1 , a height of the second microlens protruding from the first surface is greater than or equal to 0.01 mm and less than or equal to 0.0175 mm.

13. The optical lens according to any one of claims 1 to 12, characterized in that: The microlens array and the light-transmitting substrate are integrally formed, and the materials of the microlens array and the light-transmitting substrate include at least one of glass, sapphire, polyamide, polycarbonate, polymethyl methacrylate, thermoplastic polyurethane elastomer rubber and transparent nylon.

14. A photoplethysmograph, characterized in that: include: a cover plate, the cover plate comprising a first light-transmitting portion and a second light-transmitting portion; a light emitter, the light emitter being located on the inner side of the cover plate, with a light emitting surface of the light emitter facing the first light-transmitting portion; a light receiver, the light receiver being located on the inner side of the cover plate, with a light incident surface of the light receiver facing the second light-transmitting portion; An optical lens, wherein the optical lens is the optical lens according to any one of claims 1 to 13, wherein the optical lens is arranged on the surface of the first light-transmitting portion facing the light emitter, and the first surface of the optical lens faces the light emitter, and the second surface faces the first light-transmitting portion.

15. The photoplethysmograph according to claim 14, wherein The array center of the microlens array of the optical lens is aligned with the center of the light emitting surface of the light emitter.

16. The photoplethysmograph according to claim 14 or 15, characterized in that The optical lens and the first light-transmitting portion are integrally formed.

17. The photoplethysmograph according to any one of claims 14 to 16, characterized in that The cover plate further includes a light-shielding portion, which is opaque and located at least between the first light-transmitting portion and the second light-transmitting portion.

18. An electronic device, characterized in that: comprising a display screen, a housing, and the photoplethysmograph according to any one of claims 14 to 17; The display screen is connected to the housing, and the housing includes a back cover, and the back cover is opposite to the display screen; The cover plate of the photoplethysmograph is arranged on the back cover, and the light emitter and the light receiver of the photoplethysmograph are located in the housing.

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