Wearable device

Abstract

The present application provides a wearable device, which relates to the field of terminal technologies. The wearable device includes a PPG module; the PPG module includes a light-emitting unit, and the light-emitting unit includes a packaging substrate, a light-emitting chip layer, and a packaging glue layer arranged along a first direction; the light-emitting unit further includes a first microlens layer disposed on a side of the packaging glue layer away from the light-emitting chip layer, and / or a second microlens layer disposed on a side of the light-emitting chip layer away from the packaging substrate; both the first microlens layer and the second microlens layer are used to enhance the light flux and change the light shape. The wearable device improves the light-emitting efficiency by adding a first microlens layer and / or a second microlens layer in the light-emitting unit.

Description

Technical Field

[0001] This application relates to the technical field of terminals, and particularly to a wearable device. Background Art

[0002] With the explosive growth of wearable devices such as smart watches and sports bracelets, more and more functions are integrated on wearable devices. For example, users can use wearable devices to measure vital signs information such as heart rate, pulse, or blood oxygen saturation.

[0003] When measuring vital signs information, a wearable device can be based on a light emitting unit and a light receiving unit, and use photoplethysmography (PPG) to measure the attenuated light after reflection and absorption by human blood vessels and tissues, record the pulsation state of blood vessels, and measure the pulse wave.

[0004] In the above method, the light output efficiency of the light emitted by the light emitting unit through the back cover of the wearable device is a key parameter affecting the PPG performance. However, in the prior art, this light output efficiency is not high. For this reason, a new design solution is urgently needed. Summary of the Invention

[0005] This application provides a wearable device, and by adding one or more layers of microlens arrays in the light emitting unit, the purpose of improving the light output efficiency of the light emitting unit is achieved.

[0006] In a first aspect, a wearable device is provided, and the wearable device includes a PPG module;

[0007] The PPG module includes a light emitting unit, and the light emitting unit includes a packaging substrate, a light emitting chip layer, and a packaging glue layer arranged along a first direction;

[0008] The light emitting unit further includes a first microlens layer disposed on a side of the packaging glue layer away from the light emitting chip layer, and / or a second microlens layer disposed on a side of the light emitting chip layer away from the packaging substrate;

[0009] Both the first microlens layer and the second microlens layer are used to enhance the light flux and change the light shape.

[0010] Wherein, the first direction indicates the thickness direction of the light emitting unit in the embodiments of this application, that is, the direction z.

[0011] An embodiment of the present application provides a wearable device. The light-emitting unit included in the PPG module of the wearable device includes, in addition to a packaging substrate, a light-emitting chip layer, and a packaging glue layer, one or more layers of microlens arrays. The one or more layers of microlens arrays are disposed on the light-emitting side of the light-emitting chip layer, for example, on the light-emitting surface of the light-emitting chip layer, or on the packaging glue layer, to enhance the light-emitting efficiency of the light-emitting unit, or in other words, to enhance the light flux of the emitted light.

[0012] Since the microlens array also changes the light path, it is also possible to adjust the light-emitting shape of the light-emitting chip layer, such as adjusting the light-emitting angle, the light density distribution, etc.

[0013] In combination with the first aspect, in some implementation manners of the first aspect, the first microlens layer includes a plurality of first microlenses, and the first microlens is a first convex lens composed of a first plane and a first convex surface;

[0014] The first plane is located on the side close to the packaging glue layer, and the first convex surface is located on the side away from the packaging glue layer.

[0015] In this implementation manner, since the first microlens is a first convex lens, the first plane is located on the side close to the packaging glue layer, the first convex surface is located on the side away from the packaging glue layer, and the surface of the first microlens close to the air side has an increased area relative to the plane, thereby enhancing the light-emitting efficiency.

[0016] In combination with the first aspect, in some implementation manners of the first aspect, the refractive index of the first microlens layer is greater than the refractive index of air and less than or equal to the refractive index of the packaging glue layer.

[0017] In this implementation manner, when the refractive index of the first microlens is equal to the refractive index of the packaging glue layer, when light rays are emitted from the packaging glue layer into the first microlens, the light rays undergo a certain refraction and no total reflection occurs; when the refractive index of the first microlens is less than the refractive index of the packaging glue layer, when light rays are emitted from the relatively high-refractive-index packaging glue layer into the relatively low-refractive-index first microlens, the light rays will undergo refraction and total reflection, and the total reflection causes a decrease in the light output; however, because the added first microlens is in the shape of a convex lens, that is, because of the curvature of the first microlens, when the light rays are emitted from the relatively high-refractive-index first microlens into the relatively low-refractive-index air, compared with the light rays emitted from a plane, the total reflection is destroyed, thereby improving the light-emitting efficiency to a certain extent.

[0018] It should be understood that the "high" and "low" in the description of the high refractive index and low refractive index in the present application are relative and not fixed.

[0019] In combination with the first aspect, in some implementation manners of the first aspect, the plurality of first microlenses are arranged in a first array on the packaging glue layer.

[0020] In this implementation, when arranged in the first array pattern, by utilizing the array arrangement relationship among multiple first microlenses, the light shape of the light emitted into the air can be adjusted, such as the light emission angle of the light and the density distribution of the light.

[0021] Combined with the first aspect, in some implementations of the first aspect, the second microlens layer includes multiple second microlenses, and the second microlens is a second convex lens composed of a second plane and a second convex surface;

[0022] The second plane is located on the side close to the light-emitting chip layer, and the second convex surface is located on the side away from the light-emitting chip layer.

[0023] In this implementation, since the second microlens is a second convex lens, the second plane is located on the side close to the light-emitting chip layer, the second convex surface is located on the side away from the light-emitting chip layer, and the surface of the second microlens close to the encapsulation glue layer has an increased area relative to the plane area, thereby enhancing the light extraction efficiency.

[0024] Combined with the first aspect, in some implementations of the first aspect, the refractive index of the second microlens layer is greater than the refractive index of the encapsulation glue layer and less than or equal to the refractive index of the light-emitting chip layer.

[0025] In this implementation, when the refractive index of the second microlens is equal to the refractive index of the LED chip layer, when light travels from the LED chip layer into the second microlens, the light undergoes a certain degree of refraction and no total internal reflection occurs; while when the refractive index of the second microlens is less than the refractive index of the LED chip layer, when light travels from the LED chip layer with a relatively high refractive index into the second microlens with a relatively low refractive index, total internal reflection of the light will occur, resulting in a decrease in the light output. However, because the added second microlens is in the shape of a convex lens, that is, due to the existence of the curvature of the second microlens, when light travels from the second microlens with a relatively high refractive index into the encapsulation glue layer with a relatively low refractive index, compared with the light emitted from a plane, the total internal reflection is disrupted, thereby also improving the light extraction efficiency to a certain extent.

[0026] Combined with the first aspect, in some implementations of the first aspect, the light-emitting chip layer includes multiple light-emitting chips arranged at intervals;

[0027] The multiple second microlenses are arranged in a second array pattern on the light-emitting chips.

[0028] In this implementation, when arranged in the second array pattern, by utilizing the array arrangement relationship among multiple second microlenses, the light shape of the light emitted into the encapsulation glue layer can be adjusted, such as the light emission angle of the light and the density distribution of the light.

[0029] In combination with the first aspect, in some implementations of the first aspect, the first array type and the second array type are respectively at least one of the following:

[0030] Multi-row and multi-column type, circular ring type.

[0031] In combination with the first aspect, in some implementations of the first aspect, the light-emitting chip is an LED chip, and the LED chip is at least one of the following:

[0032] Yellow LED chip, green LED chip, blue LED chip, red LED chip, cyan LED chip, orange LED chip, infrared LED chip;

[0033] Among them, the yellow LED chip is used to emit yellow light with a peak wavelength range of 550.0 nm to 579.9 nm; the green LED chip is used to emit filtered light with a peak wavelength range of 510.0 nm to 549.9 nm; the cyan LED chip is used to emit cyan light with a peak wavelength range of 480.0 nm to 509.9 nm; the blue LED chip is used to emit blue light with a peak wavelength range of 450.0 nm to 479.9 nm; the red LED chip is used to emit red light with a peak wavelength range of 610.0 nm to 699.9 nm; the orange LED chip is used to emit light with a peak wavelength range of 580.0 nm to 609.9 nm; the infrared LED chip is used to emit infrared light with a peak wavelength range of 700.0 nm to 1100.0 nm.

[0034] It should be understood that in the embodiments of the present application, when the light-emitting chip is an LED chip, the light-emitting chip layer can also be referred to as an LED chip layer.

[0035] In this implementation, the light-emitting chip can be used to emit various color lights. Based on this, the characteristic dimensions of the above-mentioned first microlens and second microlens can be adaptively adjusted and prepared according to the wavelength of the light, so as to achieve the purpose of improving the light extraction efficiency for lights of different wavelengths. Among them, the characteristic dimensions include curvature, diameter, and filling ratio.

[0036] In combination with the first aspect, in some implementations of the first aspect, the first microlens array is prepared by a mold forming process.

[0037] In this implementation, the preparation method is simple and fast, and the characteristic dimensions of the first microlens layer can also be flexibly adjusted by adjusting the transfer size of the mold.

[0038] In combination with the first aspect, in some implementations of the first aspect, the second microlens array is prepared by an etching and stripping process or an annealing process.

[0039] In this implementation manner, both the etching and stripping process and the annealing process belong to the patterning process. Through the patterning process, the present application can mass-produce second microlenses on the LED chip, with mature technology, convenient implementation, and low cost.

[0040] Combined with the first aspect, in some implementation manners of the first aspect, the encapsulation substrate may be at least one of an epoxy molding compound substrate, a ceramic substrate, an aluminum substrate, a copper substrate, a silicon substrate, etc.

[0041] Combined with the first aspect, in some implementation manners of the first aspect, when the encapsulation substrate is the ceramic substrate, the light-emitting chip layer is fixed on the ceramic substrate by means of flip-chip bonding.

[0042] In this implementation manner, by using flip-chip bonding technology for fixation, the interconnection line between the LED chip and the driving circuit in the encapsulation substrate is short, and the parasitic capacitance, parasitic inductance, etc. are all very small.

[0043] Combined with the first aspect, in some implementation manners of the first aspect, the PPG module further includes a light-receiving unit; the light-emitting unit and the light-receiving unit are arranged on the same layer in a plane perpendicular to the first direction.

[0044] In this implementation manner, since the distances between the light-emitting unit and the light-receiving unit and the human body are the same, the light-receiving unit will not be affected by other factors such as distance when detecting the vital sign information.

[0045] Combined with the first aspect, in some implementation manners of the first aspect, the wearable device is a smart watch or a smart bracelet.

[0046] The embodiment of the present application provides a wearable device. The wearable device includes a PPG module, and the PPG module includes a light-emitting unit. The light-emitting unit includes an encapsulation substrate, a light-emitting chip layer (LED chip layer), and an encapsulation glue layer. In the present application, by adding a plurality of second microlenses arranged in a second array on the LED chip layer, the light output is increased by using the shape of each second microlens; and by using the array arrangement relationship between the plurality of second microlenses, the light shape of the light emitted into the encapsulation glue layer is adjusted, and then the light shape of the light emitted into the air subsequently can be adjusted.

[0047] In addition, the embodiment of the present application also adds a plurality of first microlenses arranged in a first array on the encapsulation glue layer, increases the light output by using the shape of the first microlens; and adjusts the light shape of the light emitted into the air by using the array arrangement relationship between the plurality of first microlenses, such as the light emission angle and the density distribution of the light.

[0048] It should be understood that the light output and light shape of the light finally emitted into the air will be affected by both the second microlens and the first microlens. Description of the Drawings

[0049] Figure 1 is the usage status of a wearable device provided by an embodiment of the present application;

[0050] Figure 2 is a schematic structural diagram of a wearable device provided by an embodiment of the present application;

[0051] Figure 3 is Figure 2 a top view schematic diagram of the PPG module shown in

[0052] Figure 4 is Figure 2 another top view schematic diagram of the PPG module shown in

[0053] Figure 5 is a schematic diagram of the working principle of a PPG module provided by the related art;

[0054] Figure 6 is Figure 5 a schematic structural diagram of the light emitting unit in the PPG module shown in

[0055] Figure 7 is the first schematic structural diagram of the light emitting unit provided by an embodiment of the present application;

[0056] Figure 8 is Figure 7 a schematic structural diagram of the first microlens layer in

[0057] Figure 9 is the second schematic structural diagram of the light emitting unit provided by an embodiment of the present application;

[0058] Figure 10 is Figure 9 a schematic structural diagram of the second microlens layer in

[0059] Figure 11 is the third schematic structural diagram of the light emitting unit provided by an embodiment of the present application;

[0060] Figure 12 is Figure 11 a top view schematic diagram of the first microlens layer and the second microlens layer in

[0061] Figure 13 is the light output and ray simulation diagram corresponding to the light emitting unit provided by the related art;

[0062] Figure 14 is the light output and ray simulation diagram corresponding to the light emitting unit provided by an embodiment of the present application.

[0063] Reference numerals:

[0064] 1 - Wearable device; 2 - Skin; 10 - PPG module; 11 - Light - emitting unit; 110 - Encapsulation substrate; 111 - LED chip layer; 1110 - LED chip; 112 - Encapsulation adhesive layer; 113 - First microlens layer; 1130 - First microlens; 114 - Second microlens layer; 1140 - Second microlens; 115 - Dam; 12 - Light - receiving unit. Detailed implementation manners

[0065] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are some but not all of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the scope of protection of the present application.

[0066] The term "and / or" in this document describes the association relationship of associated objects and indicates that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. The symbol " / " in this document indicates that the associated objects are in an "or" relationship. For example, A / B represents A or B.

[0067] The terms "first" and "second" in the description and claims of this document are used to distinguish different objects rather than to describe a specific order of objects. In the description of the embodiments of the present application, unless otherwise specified, the meaning of "a plurality of" refers to two or more. For example, a plurality of processing units refers to two or more processing units, and a plurality of elements refers to two or more elements.

[0068] Figure 1 The usage state of a wearable device provided in an embodiment of the present application is shown. As Figure 1 shown, the wearable device 1 can be a smart watch. When the user wears the smart watch, the bottom of the smart watch (the side opposite to the display screen) can contact the user's skin 2. The embodiment of the present application does not specifically limit the form of the wearable device 1. Exemplarily, the wearable device 1 in the embodiment of the present application can also be a sports bracelet, a smart wristband, a smart ring, etc. In the following embodiments, the wearable device 1 is taken as a smart watch for illustration.

[0069] Figure 2 The structural schematic diagram of a wearable device 1 provided in an embodiment of the present application is shown. As Figure 2As shown, the wearable device 1 includes a PPG module 10, which can be disposed on the side of the wearable device 1 in contact with the human body, for implementing photoplethysmography, measuring the attenuated light reflected and absorbed by human blood vessels and tissues, recording the pulsation state of blood vessels, and measuring physical signs such as pulse waves.

[0070] As Figure 2 shown, the PPG module 10 may include a light-emitting unit 11 and a light-receiving unit 12.

[0071] The light-emitting unit 11 is used to emit light. For example, the light-emitting unit 11 may include one or more light-emitting diode (LED) chips, or the light-emitting unit 11 may include an LED chip ( Figure 2 not shown), and other devices are also included. One LED chip can emit one color of light, and multiple LED chips can emit multiple colors of light or the same color of light. If the light-emitting unit 11 includes multiple LED chips, when the multiple LED chips emit a single color of light, the light-emitting unit 11 emits the same color of light; when the multiple LED chips emit multiple colors of light, the light-emitting unit 11 emits a mixed light of multiple colors. The embodiments of the present application do not limit the light-emitting color of the LED chip and the light-emitting unit 11.

[0072] The light-receiving unit 12 is used to receive light. It should be understood that the light received by the light-receiving unit 12 in the PPG module 10 is the attenuated light reflected and absorbed by the light emitted by the light-emitting unit 11 through human blood vessels and tissues. The light-receiving unit 12 can also be called a detector.

[0073] The above is an example description of the PPG module 10 and the wearable device 1, and does not make any limitation on the PPG module 10 and the wearable device 1 of the present application. The PPG module 10 may further include other units, and the wearable device 1 may further include other modules.

[0074] In order to further illustrate the structure of the PPG module 10, Figure 3 a top view schematic diagram of a PPG module 10 provided by an embodiment of the present application is shown; Figure 4 a top view schematic diagram of another PPG module 10 provided by an embodiment of the present application is shown.

[0075] Exemplarily, if the wearable device 1 has a circular structure in the top view angle, the light-emitting unit 11 and the light-receiving unit 12 can be arranged around the center of the circle.

[0076] For example, as Figure 3As shown, the PPG module 10 in the wearable device 1 includes three light-emitting units 11 and three light-receiving units 12. The three light-emitting units 11 and the three light-receiving units 12 are arranged around the center of a circle. Additionally, for uniform light emission and light reception, and to obtain more accurate data during subsequent light reception, the three light-emitting units 11 and the three light-receiving units 12 can be arranged at intervals.

[0077] Exemplarily, if the wearable device 1 has a rectangular structure from a top-down view, the light-emitting units 11 and the light-receiving units 12 can be arranged in rows or columns, or alternatively, they can be arranged in an array.

[0078] For example, as Figure 4 shown, the PPG module 10 in the wearable device 1 includes two light-emitting units 11 and one light-receiving unit 12. The two light-emitting units 11 are distributed on both sides of the light-receiving unit 12.

[0079] In the above two examples, each light-emitting unit 11 can include, for example, three LED chips. The three LED chips can emit red light, green light, and blue light respectively, and the shape of each LED chip is square in the above top-down view.

[0080] Figure 5 shows a schematic diagram of the working principle of the PPG module 10 provided by the related art.

[0081] Combined with Figures 1 to 5 , when the user wears the wearable device 1, the bottom of the wearable device 1 contacts the user's skin 2. It can be considered that the PPG module 10 contacts the user's skin 2. During actual wearing, Figure 5 there may still be a certain gap between the PPG module 10 and the skin 2 shown in

[0082] As Figure 5 shown, when measuring using the PPG module 10, the multiple LED chips included in the light-emitting unit 11 can emit light toward the side of the skin 2, and the angle of the light is not limited. After the light enters the skin 2, when the blood flow dynamics in the human body change, such as when the heart rate or blood volume changes, the light entering the skin 2 will be scattered, thereby affecting the transmission and reflection of the light entering the skin 2; therefore, when the light passes through the skin 2 and then exits to the light-receiving unit 12 in the PPG module 10, the light will have a certain attenuation; the attenuated light can be processed by the light-receiving unit 12, converted into an electrical signal, and can be further used to analyze the fluctuation state of blood vessels, measure physical signs such as pulse waves, etc.; subsequently, the user can perform health management based on the physical sign information obtained from the above measurement.

[0083] On the basis of Figure 5 , Figure 6 shows Figure 5Schematic structural diagram of the light-emitting unit 11 in the PPG module 10 shown. As Figure 6 shown, in the direction of the light-emitting unit 11 facing the bottom of the wearable device 1, that is, in the direction facing the human skin (such as Figure 5 and Figure 6 the direction z shown), it generally sequentially includes a packaging substrate 110, an LED chip layer 111, and a packaging glue layer 112.

[0084] Among them, the packaging substrate 110 is used to provide support and drive. For example, the packaging substrate 110 may include a plurality of thin film transistor (TFT) circuits for driving the LED chip layer 111 (such as Figure 5 and Figure 6 the black line segments in the packaging substrate 110 shown), and the TFT circuits drive the LED chip layer 111 to emit light.

[0085] The packaging glue layer 112 is used to protect the LED chip layer 111, and the packaging glue layer 112 is in a transparent state and is used to emit the light emitted by the LED chip layer 111.

[0086] The LED chip layer 111 may include, for example, 3 LED chips 111; in a plane perpendicular to the direction z, the 3 LED chips 111 are arranged at intervals, and the 3 LED chips 111 may emit different colors of light or the same color of light. In the area of the packaging substrate 110 where the LED chips 111 are not arranged, the packaging glue layer 112 is in direct contact with the packaging substrate 110.

[0087] In addition, as Figure 5 and Figure 6 shown, light-blocking walls 115 are also provided on the left and right sides of the packaging glue layer 112, and the light-blocking walls 115 are used to block light and prevent the light emitted by the LED chips 111 from leaking from the left and right sides. The left and right sides refer to the left and right in the direction perpendicular to the direction z.

[0088] Combined with Figure 5 and Figure 6As shown, when measuring physiological sign information using the wearable device 1 including the PPG module 10 structure, the higher the light output efficiency of the light emitting unit 11, the more attenuated light is received by the light receiving unit 12, and the higher the accuracy of the measured physiological sign information; the lower the light output efficiency of the light emitting unit 11, the less attenuated light is received by the light receiving unit 12, and the lower the accuracy of the measured physiological sign information. It can be seen that the light output efficiency of the light emitting unit 11 is a key parameter affecting the PPG performance. However, in the prior art, due to limitations such as materials and structures, a large amount of total internal reflection occurs inside the light emitting unit 11, resulting in a low light output efficiency of the light emitting unit 11, and thus a low accuracy of measuring physiological sign information. For this, a new solution is urgently needed to solve this problem.

[0089] In view of this, an embodiment of the present application provides a wearable device. The light emitting unit included in the PPG module in this wearable device, in addition to including a packaging substrate, an LED chip layer, and a packaging glue layer, further includes one or more layers of microlens arrays. The one or more layers of microlens arrays are arranged on the light output side of the LED chip layer, for example, on the light output surface of the LED chip layer, or on the packaging glue layer, to enhance the light output efficiency of the light emitting unit, or rather, enhance the light flux of the light output.

[0090] Since the microlens array also changes the light path, therefore, it is also possible to adjust the light output shape of the LED chip, such as adjusting the light output angle, the light density distribution, etc.

[0091] Next, in combination with Figures 7 to 12 The structure of the light emitting unit 11 in the wearable device provided by the embodiment of the present application will be introduced in detail. Figure 7 、 Figure 9 and Figure 11 respectively show three structures of the light emitting unit 11 provided by the embodiment of the present application. Figure 8 For Figure 7 is a schematic structural diagram of the first microlens layer 113 in Figure 10 For Figure 9 is a schematic structural diagram of the second microlens layer 114 in Figure 12 For Figure 11 is a top view schematic diagram of the first microlens layer 113 and the second microlens layer 114 in

[0092] As Figure 7 shown, the light emitting unit 11 of the first structure provided by the embodiment of the present application, in the direction z towards the bottom of the wearable device 1, sequentially includes: a packaging substrate 110, an LED chip layer 111, and a packaging glue layer 112.

[0093] Exemplarily, the encapsulation substrate 110 can be at least one of an epoxy mold compound (EMC) substrate, a ceramic substrate, an aluminum substrate, a copper substrate, a silicon substrate, etc.; in addition, for other introductions of the encapsulation substrate 110, reference can be made to Figure 5 and Figure 6 the introductions of the encapsulation substrate 110 in

[0094] which will not be elaborated herein.

[0095] Exemplarily, the shape of each LED chip 1110 in a top view can be square, rectangular, circular, or irregular, etc. In addition, the LED chip 1110 can also be changed to other non-LED light-emitting chips, and the embodiments of the present application do not make any limitations thereto.

[0096] Exemplarily, when the encapsulation substrate 110 is a ceramic substrate, the LED chip 1110 can be fixed on the ceramic substrate by flip-chip bonding. It should be noted that the flip-chip bonding method refers to a technology in which the LED chip 1110 is directly interconnected with the ceramic substrate, also known as the flip-chip bonding method.

[0097] The thickness of the encapsulation glue layer 112 in the z direction (the dimension from the interface between the LED chip layer 111 and the encapsulation glue layer 112 to the interface between the encapsulation glue layer 112 and the air) is higher than the thickness of the LED chip layer 111. For other introductions, reference can be made to the above Figure 5 and Figure 6 introductions of the encapsulation glue layer 112, which will not be elaborated herein.

[0098] Based on the above structure, as Figure 7As shown in the figure, the light-emitting unit 11 of the first structure provided by the embodiment of the present application sequentially includes a packaging substrate 110, an LED chip layer 111, and a packaging glue layer 112. On the side of the packaging glue layer 112 away from the LED chip layer 111, a first microlens layer 113 is further provided.

[0099] The first microlens layer 113 includes a plurality of first microlenses 1130, and the plurality of first microlenses 1130 are arranged in a first array on the surface of the packaging glue layer 112 on the side away from the LED chip layer 111.

[0100] It should be understood that the first array arrangement means that the plurality of first microlenses 1130 are arranged in a certain order, for example, it can include: multiple rows and multiple columns, circular rings, etc.; there may be no gap between two adjacent first microlenses 1130, or there may be a certain gap. The specific arrangement method of the first microlenses 1130, whether there is a gap and the size of the gap can all be set as needed, and the embodiment of the present application does not make any limitation on this.

[0101] Each first microlens 1130 is in a transparent state, so that the light emitted from the LED chip layer 111 and transmitted through the packaging glue layer 112 is transmitted through the first microlens 1130 and then emitted into the air, and then transmitted to the user's skin 2.

[0102] The first microlens layer 113 also has adjustable characteristic dimensions, and the characteristic dimensions can include the curvature, diameter, filling ratio, etc. corresponding to the first microlenses 1130.

[0103] It should be understood that in order to increase the surface area of the side of the first microlens 1130 close to the air and enhance the light output, the shape of each first microlens 1130 can be convex, that is, the first microlens 1130 can be called a first convex lens, and the first convex lens is composed of a first plane and a first convex surface. For example, as Figure 8 shown in (a) of, the convex first convex surface of the first microlens 1130 is a hemispherical surface, and the curvature of the first microlens 1130 is γ1.

[0104] Exemplarily, as Figure 7 and Figure 8 shown in (a) of, the shape of the first microlens 1130 can be a hemisphere, the bottom surface (circular in the top view) included in the hemisphere is in contact with the packaging glue layer 112, and the hemispherical surface included in the hemisphere is close to the air side.

[0105] As Figure 8 shown in (b) of, the diameter of the first microlens 1130 in the shape of a hemisphere can be d1; when the length of the packaging substrate 110 is represented as L x1 , the width is represented as L y1, when multiple first microlenses 1130 are arranged in multiple rows and columns, M first microlenses 1130 with a diameter of d1 can be arranged in the length direction, and N first microlenses 1130 with a diameter of d1 can be arranged in the width direction. At this time, the filling ratio T1 of the first microlenses 1130 can be calculated according to the following formula: x1 When multiple first microlenses 1130 are arranged in multiple rows and columns, M first microlenses 1130 with a diameter of d1 can be arranged in the length direction, and N first microlenses 1130 with a diameter of d1 can be arranged in the width direction. At this time, the filling ratio T1 of the first microlenses 1130 can be calculated according to the following formula: y1 T1 = (πd1

[0106] × M 2 × N x1 × N y1 ) / (4 × L x1 × L y1 );

[0107] Assume that the encapsulation substrate 110 is square, L x1 = L y1 , then the filling ratio T1 of the first microlenses 1130 can be:

[0108] T1 = (πd1 2 × M x1 × N y1 ) / (2L1) 2 ;

[0109] It should be understood that since it is necessary to increase the light output, a material with a first refractive index can be selected to make the first microlenses 1130, so that the light can be refracted at least at the surface of the first microlenses 1130 close to the air side, and the incident angle of the light is less than the refraction angle. Then, the first refractive index needs to meet the conditions of being greater than the refractive index of air and less than or equal to the refractive index of the encapsulation adhesive layer 112.

[0110] Exemplarily, if the refractive index of the encapsulation adhesive layer 112 is 1.6 and the refractive index of air is 1, the first refractive index corresponding to the first microlenses 1130 needs to meet the conditions of being greater than 1 and less than or equal to 1.6. For example, the refractive index of the first microlenses 1130 can be 1.4, 1.5, 1.6, etc.

[0111] It should be understood that when the refractive index of the first microlens 1130 is equal to that of the encapsulation adhesive layer 112, when light rays exit from the encapsulation adhesive layer 112 into the first microlens 1130, the light rays undergo a certain degree of refraction and do not undergo total internal reflection; while when the refractive index of the first microlens 1130 is less than that of the encapsulation adhesive layer 112, when light rays exit from the relatively high refractive index encapsulation adhesive layer 112 into the relatively low refractive index first microlens 1130, the light rays will undergo refraction and total internal reflection, and the total internal reflection causes a decrease in the light output. However, because the added first microlens 1130 is in the shape of a convex lens, that is, due to the existence of the curvature of the first microlens 1130, when light rays exit from the relatively high refractive index first microlens 1130 into the relatively low refractive index air, compared with the plane-emitted light rays, the total internal reflection is disrupted, thereby improving the light output efficiency to a certain extent.

[0112] Exemplarily, when the first refractive index corresponding to the first microlens 1130 is in the range of 1.4 to 1.6, the first microlens 1130 can be at least one of a polycarbonate lens, a polymethyl methacrylate lens, a glass lens, a silicone lens, or an epoxy resin lens; of course, the first microlens 1130 can also be other lenses that meet the first refractive index requirement, and the embodiments of the present application do not make any limitations in this regard.

[0113] The embodiments of the present application can transfer the first microlens layer 113 on the surface of the encapsulation adhesive layer 112 by using a molding process, which is simple and fast; subsequently, for the first microlenses 1130 with different feature sizes, adjustment can also be made by adjusting the transfer size of the molding die, thereby realizing the flexible adjustment of the first microlens layer 113.

[0114] The light-emitting unit 11 provided by the embodiments of the present application increases the light output by using the shape of the first microlenses 1130 through adding a plurality of first microlenses 1130 arranged in a first array on the encapsulation adhesive layer 112; and adjusts the light shape of the light rays exiting into the air by using the array arrangement relationship between the plurality of first microlenses 1130, such as the light exit angle and the density distribution of the light rays.

[0115] As Figure 9 shown, the light-emitting unit 11 of the second structure provided by the embodiments of the present application sequentially includes: an encapsulation substrate 110, an LED chip layer 111, and an encapsulation adhesive layer 112 in the direction z towards the wearable device 1.

[0116] For the introduction of the encapsulation substrate 110, the LED chip layer 111, and the encapsulation adhesive layer 112, reference can be made to the introductions in the above Figure 7 and Figure 8 and will not be elaborated here.

[0117] On the basis of the above structure, as Figure 9As shown in the figure, the light-emitting unit 11 of the second structure provided by the embodiment of the present application, in addition to sequentially including a packaging substrate 110, an LED chip layer 111, and a packaging glue layer 112, further includes a second microlens layer 114 on the side of the LED chip layer 111 away from the packaging substrate 110, that is, between the LED chip layer 111 and the packaging glue layer 112.

[0118] The second microlens layer 114 includes a plurality of second microlenses 1140, and the plurality of second microlenses 1140 are arranged in a second array on the surface of the LED chip layer 111 on the side away from the packaging substrate 110. It should be understood that the second microlens layer 114 can only be provided in the area where the LED chip layer 111 is provided.

[0119] It should be understood that the second array arrangement means that the plurality of second microlenses 1140 are arranged in a certain order, for example, it can include: multiple rows and multiple columns, circular ring, etc.; there is no gap between adjacent two second microlenses 1140, or there can also be a certain gap. The specific arrangement manner of the second microlenses 1140, whether there is a gap, and the size of the gap can all be set as needed, and the embodiments of the present application do not make any limitations thereto.

[0120] Each second microlens 1140 is in a transparent state, so that the light emitted from the LED chip layer 111 is transmitted through the second microlens 1140 and then emitted into the packaging glue layer 112. Subsequently, after being transmitted through the packaging glue layer 112, it is emitted into the air, and then transmitted to the user's skin 2.

[0121] The second microlens layer 114 also has adjustable characteristic dimensions, and the characteristic dimensions can include the curvature, diameter, filling ratio, etc. corresponding to the second microlenses 1140.

[0122] It should be understood that in order to increase the surface area of the side of the second microlens 1140 close to the packaging glue layer 112 and enhance the light output, the shape of each second microlens 1140 can be convex, that is, the second microlens 1140 can be called a second convex lens, and the second convex lens is composed of a second plane and a second convex surface. For example, as Figure 10 shown in (a) of the figure, the protruding side of the second microlens 1140 is a hemispherical surface, and the curvature of the second microlens 1140 is γ2.

[0123] Exemplarily, as Figure 9 and Figure 10 shown in (a) of the figure, the shape of the second microlens 1140 can be a hemisphere, the bottom surface (circular in the top view) included in the hemisphere is in contact with the LED chip layer 111, and the hemispherical surface included in the hemisphere is close to the side of the packaging glue layer 112.

[0124] As Figure 10As shown in (b) therein, the diameter of the hemispherical second microlens 1140 can be d2; when the length of the encapsulation substrate 110 is expressed as L x2 , the width is expressed as L y2 , when multiple second microlenses 1140 are arranged in multiple rows and columns, M x2 second microlenses 1140 with a diameter of d2 can be arranged in this length direction, and N y2 second microlenses 1140 with a diameter of d2 can be arranged in this width direction. At this time, the filling ratio T2 of the second microlens 1140 can be calculated according to the following formula:

[0125] T2 = (πd2 2 ×M x2 ×N y2 ) / (4×L x2 ×L y2 );

[0126] Assume that the encapsulation substrate 110 is square, L x2 = L y2 , then the filling ratio T2 of the second microlens 1140 can be:

[0127] T2 = (πd2 2 ×M x2 ×N y2 ) / (2L2) 2 ;

[0128] In the embodiments of the present application, the second microlens layer 114 can be prepared by an etching and peeling process or an annealing process; in the embodiments of the present application, other patterning processes can also be used to prepare the second microlens layer 114, and the specific selection of the process depends on the material properties of the LED chip 111.

[0129] Exemplarily, the etching and peeling process is applicable to any LED chip material; if the etching and peeling process is adopted, the LED chip layer 111 and the second microlens layer 114 need to be fabricated separately. For example, a lens thin film including the second microlens layer 114 can be first prepared on a substrate (such as a glass substrate) by an etching method, and then the lens thin film can be peeled off from the substrate by a laser peeling method and transferred to the LED chip layer 111 for bonding and dicing, so that LED chip layers 111 with a second microlens layer 114 can be obtained one by one.

[0130] Exemplarily, the annealing process can be applied to LED chip materials with a passivation layer on the surface; for example, GaN LED chips can be annealed, and for another example, polystyrene can be annealed at 150 degrees. If the annealing process is adopted, the second microlens layer 114 can be directly prepared on the LED chip layer 111. For example, a cylindrical array with a diameter of d2 can be etched on the surface of the LED chip layer 111, and then, by annealing, the cylindrical array can be changed into tiny hemispheres under the action of thermal stress, so that the LED chip layer 111 with the second microlens layer 114 can be obtained.

[0131] It should be understood that since it is necessary to increase the light output, a material with a second refractive index can be selected to make the second microlens 1140, so that the light can be refracted at least on the surface of the second microlens 1140 close to the encapsulant layer 112, and the incident angle of the light is less than the refraction angle. Then, the second refractive index needs to satisfy the condition of being greater than the refractive index of the encapsulant layer 112 and less than or equal to the refractive index of the LED chip layer 111. It should be noted that the refractive index of the LED chip layer 111 refers to the refractive index of the light-emitting surface included in the LED chip 1110 itself.

[0132] Exemplarily, if the refractive index of the LED chip layer 111 is 2.6 and the refractive index of the encapsulant layer 112 is 1.5, the second refractive index corresponding to the second microlens 1140 needs to satisfy the condition of being greater than 1.5 and less than or equal to 2.6. For example, the refractive index of the second microlens 1140 can be 1.6, 1.8, 2.5, etc.

[0133] It should be understood that when the refractive index of the second microlens 1140 is equal to the refractive index of the LED chip layer 111, total internal reflection does not occur when the light exits from the LED chip layer 111 into the second microlens 1140; while when the refractive index of the second microlens 1140 is less than the refractive index of the LED chip layer 111, when the light exits from the relatively high-refractive-index LED chip layer 111 into the relatively low-refractive-index second microlens 1140, total internal reflection of the light will occur, resulting in a decrease in the light output to some extent. However, because the added second microlens 1140 is in the shape of a convex lens, that is, due to the existence of the curvature of the second microlens 1140, when the light exits from the relatively high-refractive-index second microlens 1140 into the relatively low-refractive-index encapsulant layer 112, compared with the plane-emitted light, total internal reflection is destroyed, and thus the light output efficiency can also be improved to a certain extent.

[0134] Exemplarily, when the second refractive index corresponding to the second microlens 1140 is in the range of 1.5 to 2.6, the second microlens 1140 can be at least one of a silicon oxide lens, a silicon carbide lens, and a silicon nitride lens. Of course, the second microlens 1140 can also be other lenses based on silicon materials that meet the requirements of the second refractive index, and the embodiments of the present application do not make any limitations thereto.

[0135] The light-emitting unit 11 provided in the embodiment of the present application adds a plurality of second microlenses 1140 arranged in a second array on the LED chip layer 111, so that the light output can be increased by using the shape of each second microlens 1140; and by using the array arrangement relationship between the plurality of second microlenses 1140, the light shape of the light emitted into the encapsulation glue layer 112 can be adjusted, and then the light shape of the light emitted into the air subsequently can be adjusted, such as the light output angle and the density distribution of the light.

[0136] In addition, the second microlenses 1140 can be prepared on the LED chip 1110 on a large scale through a patterning process, with mature technology, convenient implementation and low cost.

[0137] As Figure 11 shown, the light-emitting unit 11 of the third structure provided in the embodiment of the present application sequentially includes, in the direction z towards the wearable device 1: a packaging substrate 110, an LED chip layer 111, and an encapsulation glue layer 112.

[0138] For the introduction of the packaging substrate 110, the LED chip layer 111, and the encapsulation glue layer 112, reference can be made to the introductions in the above Figure 7 and Figure 8 , and details will not be repeated here.

[0139] On the basis of the above structure, as Figure 11 shown, the light-emitting unit 11 of the third structure provided in the embodiment of the present application, in addition to sequentially including a packaging substrate 110, an LED chip layer 111, and an encapsulation glue layer 112, further has a first microlens layer 113 provided on the side of the encapsulation glue layer 112 away from the LED chip layer 111; and a second microlens layer 114 is also provided between the LED chip layer 111 away from the packaging substrate 110, that is, between the LED chip layer 111 and the encapsulation glue layer 112.

[0140] For the introduction of the first microlens layer 113, reference can be made to the introductions in the above Figure 7 and Figure 8 , and for the introduction of the second microlens layer 114, reference can be made to the introductions in the above Figure 9 and Figure 10 , and details will not be repeated here.

[0141] It should be understood that the array arrangement of the plurality of first microlenses 1130 included in the first microlens layer 113 and the array arrangement of the plurality of second microlenses 1140 included in the second microlens layer 114 may be the same or different. For example, the first microlens layer 113 is arranged in a first array of multiple rows and multiple columns, and the second microlens layer 114 is arranged in a second array in a circular ring shape. The specific arrangement of the first microlens layer 113 and the second microlens layer 114 can be set as needed, and the embodiments of the present application do not make any limitations thereto.

[0142] It should be understood that the adjustable characteristic dimensions of the first microlens layer 113 and the second microlens layer 114 may be the same or different. For example, as Figure 12 shown, when setting, the curvature corresponding to the second microlens 1140 can be made smaller than the curvature corresponding to the first microlens 1130, the diameter corresponding to the second microlens 1140 can also be smaller than the curvature corresponding to the first microlens 1130, and the filling ratio corresponding to the second microlens 1140 is greater than the filling ratio corresponding to the first microlens 1130. Specifically, it can be set as needed, and the embodiments of the present application do not make any limitations thereto.

[0143] The techniques for preparing the first microlens layer 113 and the second microlens layer 114 in the embodiments of the present application can refer to the descriptions in the above two embodiments and will not be elaborated here.

[0144] It should also be understood that both the first microlens 1130 in the first microlens layer 113 and the 1140 in the second microlens layer 114 are in a transparent state. The second refractive index corresponding to the second microlens 1140 needs to be greater than the refractive index of the encapsulation adhesive layer 112 and less than or equal to the refractive index of the LED chip 1110. The first refractive index corresponding to the first microlens 1130 needs to be greater than the refractive index of air and less than or equal to the refractive index of the encapsulation adhesive layer 112. From this, it can be seen that the second refractive index corresponding to the second microlens 1140 is greater than the first refractive index corresponding to the first microlens 1130.

[0145] Exemplarily, if the refractive index of the LED chip 1110 is 2.6, the refractive index of the encapsulation adhesive layer 112 is 1.5, and the refractive index of air is 1, then the second refractive index corresponding to the second microlens 1140 can be 1.8, and the first refractive index corresponding to the first microlens 1130 can be 1.5, and the second refractive index is greater than the first refractive index.

[0146] It should be understood that since the second microlens 1140 is added to the LED chip layer 111 and the first microlens 1130 is added to the encapsulation adhesive layer 112, both the second microlens 1140 and the first microlens 1130 disrupt total internal reflection, making the increased light output stronger than the increased light output when only disrupting total internal reflection once in the above two embodiments.

[0147] The light-emitting unit 11 provided by the embodiment of the present application increases the light output by using the shape of each second microlens 1140 through adding a plurality of second microlenses 1140 arranged in a second array on the LED chip layer 111; and adjusts the light shape of the light emitted into the encapsulation glue layer 112 by using the array arrangement relationship between the plurality of second microlenses 1140, so as to adjust the light shape of the light emitted into the air subsequently. In addition, the embodiment of the present application also increases the light output by using the shape of the first microlens 1130 through adding a plurality of first microlenses 1130 arranged in a first array on the encapsulation glue layer 112; and adjusts the light shape of the light emitted into the air, such as the light output angle and the density distribution of the light, by using the array arrangement relationship between the plurality of first microlenses 1130.

[0148] It should be understood that the light output and light shape of the light finally emitted into the air are affected by both the second microlens 1140 and the first microlens 1130.

[0149] Subsequently, when the light-emitting unit 11 provided by the embodiment of the present application is applied to the PPG module 10 in the wearable device 1 described above, the accuracy of measuring the vital signs information of the PPG module 10 can be improved by enhancing the light-emitting efficiency of the light-emitting unit 11, and thus the experience of the user wearing the wearable device 1 for health management can be improved.

[0150] It should be noted that the above three structures of the light-emitting unit 11 are only three examples. The microlens array arranged in the light-emitting unit 11 can also be arranged in other layer relationships, or multiple layers of microlens arrays can be arranged.

[0151] For example, multiple layers of second microlens layers 114 can be added on the LED chip 111, and the plurality of second microlenses 1140 in the multiple layers of second microlens layers 114 overlap with each other in the z direction, or can be arranged in a staggered manner.

[0152] For another example, multiple layers of first microlens layers 113 can be arranged on the encapsulation glue layer 112, and the plurality of first microlenses 1130 in the multiple layers of first microlens layers 113 overlap with each other in the z direction, or can be arranged in a staggered manner.

[0153] In addition, in the light-emitting unit 11 provided by the embodiment of the present application, retaining walls 115 are also arranged on the left and right sides of the encapsulation glue layer 112.

[0154] As described above in conjunction with Figures 1 to 12 the usage state and internal structure of the wearable device 1 provided by the embodiment of the present application are described. Next, in conjunction with Figure 6 , Figure 7 and Figure and ​, the effects respectively simulated for the structure of the light-emitting unit 11 provided by the related technology and the structure of the first light-emitting unit 11 provided by the embodiments of the present application are introduced.

[0155] Exemplarily, taking ​ the structure of the light-emitting unit 11 provided by the related technology shown as an example, the parameters provided in Table 1 below and the other parameters provided in Table 2 except for the first microlens layer 113 are set. Taking ​ the structure of the light-emitting unit 11 provided by the embodiments of the present application shown as an example, the parameters provided in Table 1 and Table 2 below are set.

[0156] ​ ​ ​ ​ 0.88 0.12 ​ 0.92 0.08 ​ 0.95 0.05

[0157] Table 1

[0158] ​ ​ <![CDATA[Absorption rate (mm -1 )]]> ​ 1.51 0.05 ​ 2.5 5 ​ 1.51 0.05

[0159] Table 2

[0160] Among them, in Table 1, the bottom coating of the encapsulant layer refers to the coating applied between the encapsulation substrate 110 and the encapsulant layer 112 in the area of the encapsulation substrate 110 where the LED chip 111 is not provided. This coating is used to block light leakage.

[0161] The bottom coating of the LED chip refers to the coating applied between the encapsulation substrate 110 and the LED chip 111 in the area of the encapsulation substrate 110 where the LED chip 111 is provided. This coating is used to block light leakage. The bottom coating of the LED chip can be a mirror made of silver (Ag).

[0162] Combined with the above-set parameters, for ​ the light-emitting unit 11 provided by the related technology shown, the distribution of the light output amount simulated is as shown in ​ (a) therein, and the light shape of the light is as shown in ​ (b) therein.

[0163] In ​ (a), the horizontal coordinate X and the vertical coordinate Y are respectively used to indicate the size, with the unit of millimeter; the bar chart on the left is used to indicate the correspondence between color and luminous flux, with the unit of W / m 2 . Combining ​ (a), it can be known that for the light-emitting unit 11 provided by the related technology, the total luminous flux corresponding to the light-emitting unit 11 obtained by simulation is 0.43167 W, and the ratio of the luminous flux to the emitted luminous flux is 0.43167. From this, it can be known that the light extraction rate of this light-emitting unit 11 is approximately 43.1%.

[0164] It should be understood that the emitted luminous flux can be understood as the luminous flux emitted by the LED chip 1110, corresponding to a light power of 1W.

[0165] In ​ (b) therein, the left rectangle is the light-emitting unit 11, the right rectangle is used to indicate the user's skin 2, and the line between the light-emitting unit 11 and the skin 2 is used to indicate the light. It can be seen that due to total internal reflection inside the light-emitting unit 11, the light after multiple reflections is absorbed by the baffle coating and the bottom coating of the encapsulation glue layer, so that a large amount of light does not emit; the emitted light is partially sparse and partially dense, and the distribution is uneven.

[0166] Combined with the above-set parameters, for ​ the light-emitting unit 11 provided by the embodiment of the present application shown, the distribution of the emitted light quantity simulated is as shown in ​ (a) therein, and the light shape of the light is as shown in ​ (b) therein. ​ Same as the coordinates and the meaning indicated by the lines in ​ , which will not be elaborated here.

[0167] Combined with ​ (a) therein, it can be known that for the light-emitting unit 11 provided by the embodiment of the present application, the total luminous flux corresponding to the light-emitting unit 11 obtained by simulation is 0.70526W, and the ratio of the luminous flux to the emitted luminous flux is 0.70526. It can be seen that the light extraction rate of this light-emitting unit 11 is about 70.5%.

[0168] In ​ (b) therein, since the first microlens layer is added to the light-emitting unit 11, the total internal reflection inside can be effectively reduced, so that more light is emitted and the distribution is more uniform.

[0169] Comparing ​ and ​ it can be known that the light-emitting unit 11 provided by the embodiment of the present application improves the light efficiency by more than 70%, and the effects such as the luminous flux and the light shape of the emitted light are better.

[0170] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A wearable device, characterized in that, The wearable device includes a PPG module; The PPG module includes a light-emitting unit, and the light-emitting unit includes a packaging substrate, a light-emitting chip layer, and a packaging glue layer arranged along a first direction; The light-emitting unit further includes a first microlens layer disposed on a side of the packaging glue layer away from the light-emitting chip layer and a second microlens layer disposed on a side of the light-emitting chip layer away from the packaging substrate; the refractive index of the first microlens layer is greater than the refractive index of air and less than the refractive index of the packaging glue layer; the refractive index of the second microlens layer is greater than the refractive index of the packaging glue layer and less than or equal to the refractive index of the light-emitting chip layer; The first microlens layer includes a plurality of first microlenses, the second microlens layer includes a plurality of second microlenses, and the curvature of the second microlens is less than the curvature of the first microlens; Both the first microlens layer and the second microlens layer are used to enhance the light flux and change the light shape, and the first microlens layer is prepared by a mold forming process.

2. The wearable device according to claim 1, wherein The first microlens is a first convex lens composed of a first plane and a first convex surface; The first plane is located on a side close to the packaging glue layer, and the first convex surface is located on a side away from the packaging glue layer.

3. The wearable device according to claim 2, wherein The plurality of first microlenses are arranged in a first array on the packaging glue layer.

4. The wearable device according to claim 3, wherein The second microlens is a second convex lens composed of a second plane and a second convex surface; The second plane is located on a side close to the light-emitting chip layer, and the second convex surface is located on a side away from the light-emitting chip layer.

5. The wearable device according to claim 4, wherein The light-emitting chip layer includes a plurality of spaced-apart light-emitting chips; The plurality of second microlenses are arranged in a second array on the light-emitting chips.

6. The wearable device according to claim 5, characterized in that, The first array and the second array are respectively at least one of the following: Multi-row and multi-column type, circular ring type.

7. The wearable device according to claim 5 or 6, characterized in that, The light-emitting chip is an LED chip, and the LED chip is at least one of the following: Yellow LED chip, green LED chip, blue LED chip, red LED chip, cyan LED chip, orange LED chip, infrared LED chip; Among them, the yellow LED chip is used to emit yellow light with a peak wavelength range of 550.0 nm to 579.9 nm; the green LED chip is used to emit filtered light with a peak wavelength range of 510.0 nm to 549.9 nm; the cyan LED chip is used to emit cyan light with a peak wavelength range of 480.0 nm to 509.9 nm; the blue LED chip is used to emit blue light with a peak wavelength range of 450.0 nm to 479.9 nm; the red LED chip is used to emit red light with a peak wavelength range of 610.0 nm to 699.9 nm; the orange LED chip is used to emit light with a peak wavelength range of 580.0 nm to 609.9 nm; the infrared LED chip is used to emit infrared light with a peak wavelength range of 700.0 nm to 1100.0 nm.

8. The wearable device according to claim 1, wherein The second microlens array is prepared by an etching and stripping process or an annealing process.

9. The wearable device according to claim 1, wherein The packaging substrate is at least one of an epoxy molding compound substrate, a ceramic substrate, an aluminum substrate, a copper substrate, or a silicon substrate.

10. The wearable device according to claim 9, wherein, When the encapsulation substrate is the ceramic substrate, the light-emitting chip layer is fixed on the ceramic substrate by means of flip-chip bonding.

11. The wearable device according to claim 1, wherein, The PPG module further includes a light-receiving unit; the light-emitting unit and the light-receiving unit are arranged on the same layer in a plane perpendicular to the first direction.

12. The wearable device according to claim 1, characterized in that, The wearable device is a smart watch or a smart bracelet.

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