CN117133767A

CN117133767A - PPG (PPG) packaging module and electronic equipment

Info

Publication number: CN117133767A
Application number: CN202310422573.2A
Authority: CN
Inventors: 黄书藤; 郭小丫; 黄松
Original assignee: Honor Device Co Ltd
Current assignee: Honor Device Co Ltd
Priority date: 2023-04-13
Filing date: 2023-04-13
Publication date: 2023-11-28

Abstract

The embodiment of the application provides a PPG (surface-modified) packaging module and electronic equipment, which relate to the technical field of electronics, and can reduce the height of the PPG packaging module, increase the reliability of the PPG packaging module, improve the light emitting efficiency of an LED and facilitate the detection of PPG. The PPG packaging module comprises a packaging substrate; the retaining wall structure is positioned on one side of the packaging substrate; the retaining wall structure comprises a plurality of hollowed-out parts, and the hollowed-out parts expose partial areas of the packaging substrate; the at least one light emitting module and the at least one light receiving module are respectively arranged in the plurality of hollowed-out parts and are electrically connected with the packaging substrate; the light emitting module comprises at least one LED chip, the LED chip is a flip LED chip, and the light receiving module comprises a flip photoelectric detector.

Description

PPG (PPG) packaging module and electronic equipment

Technical Field

The present application relates to the field of electronic devices, and in particular, to a PPG packaging module and an electronic device.

Background

Currently, with the development of terminal technology, terminal devices have become part of people's work and life. In order to meet the requirement of users on self health management, more terminal devices can support the human body data monitoring function of the users. For example, a user may measure a person's heart rate, respiration rate, or blood oxygen, etc., characteristics of the person using a wearable device, such as a smart watch, etc.

Typically, the terminal device may be configured with a photoplethysmography (PPG) module for measuring a human body feature, the PPG module mainly comprising a light emitting diode (light emitting diode, LED) light source and a Photodetector (PD), the detection principle of which is: after the light signals are transmitted to the skin through the LEDs, part of the light signals can be absorbed by human tissues (including blood) in the skin, part of the light signals can be scattered and reflected, and part of the scattered and reflected light signals can be received by the PDs and converted into electric signals; the scattered and reflected optical signals can change regularly along with the pulsation of the human pulse, the pulse wave change condition can be detected based on the change of the electrical signals detected by the PD, and then the data such as heart rate, blood oxygen and the like can be determined based on the pulse wave change condition.

However, the existing PPG module is limited by the large overall height, and the LED package cannot achieve both high light extraction efficiency and reliability.

Disclosure of Invention

In order to solve the technical problems, the application provides a PPG packaging module and electronic equipment, which can reduce the height of the PPG packaging module, increase the reliability of the PPG packaging module, improve the light emitting efficiency of an LED and facilitate the detection of PPG.

In a first aspect, an embodiment of the present application provides a PPG package module, including: packaging a substrate; the retaining wall structure is positioned on one side of the packaging substrate; the retaining wall structure comprises a plurality of hollowed-out parts, and the hollowed-out parts respectively expose partial areas of the packaging substrate; the at least one light emitting module and the at least one light receiving module are respectively arranged in the plurality of hollowed-out parts and are electrically connected with the packaging substrate; the light emitting module comprises at least one LED chip, the LED chip is a flip LED chip, and the light receiving module comprises a flip photoelectric detector.

According to the PPG packaging module provided by the embodiment of the application, gold wires are not required to be arranged, pins electrically connected with the gold wires are not required to be reserved on the packaging substrate, the reliability of the PPG module is improved, the risk of breakage of the gold wires in the transportation process and the installation process is reduced, and the cost increase caused by damage (very thin, such as damage caused by falling and the like) and the like of the gold wires in the packaging process and the transportation process is avoided; and avoid because the gold thread welding leads to the high of PPG module to and avoid because the area of the encapsulation base plate that leads to of reserving the pin that is connected with gold thread electricity on the encapsulation base plate is great, and then lead to the size of PPG module on the horizontal plane great, reduce the height of PPG encapsulation module to and reduce the size of PPG encapsulation module on the horizontal plane. When the PPG packaging module is applied to electronic equipment, especially for intelligent wearing equipment, the miniaturized design of the intelligent wearing equipment is facilitated, so that the requirement of a user on the miniaturization of the electronic equipment is met. In addition, when the PPG module height is reduced, the thickness of the retaining wall structure is reduced, the light absorption of the side retaining wall structure to the light signal emitted by the LED chip is reduced, the light emitting efficiency of the LED chip is improved, and the detection precision is improved. In addition, the LED chip and the PD share the packaging substrate, so that the integral packaging of the LED chip and the PD is realized, and the reliability of the PPG module is further improved.

In some possible implementations, the PPG package module further includes a first encapsulant covering at least the first and second electrodes of the LED chip.

The first packaging adhesive is arranged, so that on one hand, a first die bonding layer between the first electrode and the packaging substrate and a second die bonding layer between the second electrode and the packaging substrate can be protected from external influences, the risk of short circuit caused by migration of anions along with the action of an electric field after the die bonding layer is solidified is avoided, and the reliability of the PPG packaging module is greatly improved; on the other hand, the stability of the light type of the LED chip is ensured.

In some possible implementations, on the basis that the PPG packaging module further includes a first packaging adhesive, along the first direction, a height of the first packaging adhesive is smaller than a height of the LED chip; wherein the first direction is perpendicular to the package substrate.

By the arrangement, the reliability of the PPG packaging module can be greatly improved, the refraction inside the LED chip can be reduced, the light angle of the LED chip is reduced, the light-emitting concentration of the PPG packaging module is ensured, the refraction of light of the subsequent PPG packaging module on the skin of a human body is facilitated, and the absorption of PD to the light is facilitated.

In some possible implementations, on the basis that the PPG packaging module further includes a first packaging adhesive, along a first direction, a height of the first packaging adhesive is greater than a height of the LED chip; wherein the first direction is perpendicular to the package substrate. When the height of the first packaging adhesive is larger than that of the LED chip, the whole LED chip can be sealed and protected, so that the LED chip is suitable for severe environments.

In some possible implementations, on the basis that the PPG packaging module further includes a packaging adhesive, the refractive index n of the first packaging adhesive satisfies: n is more than or equal to 1.4 and less than or equal to 1.6 so as to enhance the light extraction efficiency of the LED chip.

In some possible implementations, the PPG packaging module further includes a first packaging adhesive, where the first packaging adhesive includes polycarbonate, polymethyl methacrylate, glass, silica gel, or epoxy resin.

In some possible implementations, the PPG packaging module further includes a second encapsulant covering at least the first and second electrodes of the flip-chip photodetector.

The setting of second encapsulation is glued, can protect flip-chip photoelectric detector's first electrode and second electrode and encapsulation base plate between the solid brilliant layer of third and fourth and be influenced by the outside, avoids solid brilliant layer solidification back anion to follow the electric field effect migration and leads to the risk of short circuit, and PPG encapsulation module reliability further promotes.

In some possible implementations, when the PPG packaging module further includes a first packaging adhesive and a second packaging adhesive, the first packaging adhesive and the second packaging adhesive are formed by the same process, so as to simplify the process steps and reduce the process cost.

In some possible implementations, a first isolation structure is disposed between the first electrode and the second electrode of the LED chip. The first electrode and the second electrode are isolated through the first isolation structure, so that the risk of short circuit caused by migration of anions under the action of an electric field after solidification of the first die bonding layer between the first electrode and the packaging substrate and the second die bonding layer between the second electrode and the packaging substrate is prevented.

In some possible implementations, a second isolation structure is provided between the two electrodes of the flip-chip photodetector. And the two electrodes of the flip photoelectric detector are isolated through the second isolation structure, so that the risk of short circuit caused by migration of anions under the action of an electric field after solidification of the third solid crystal layer and the fourth solid crystal layer between the two electrodes of the flip photoelectric detector and the packaging substrate is prevented. The first isolation structure and the second isolation structure may be formed by the same process to simplify the process steps.

In some possible implementations, the at least one LED chip includes a first LED chip, the first LED chip being a closest LED chip to the wall structure among the at least one LED chip; the distance from the first LED chip to the retaining wall structure and the height of the retaining wall structure meet the following conditions: tan theta _1＝ (H2-H1)/H3, (180-2 theta) ₁ )＞θ ₂ And H2 > H1; wherein H1 is the height of the first LED chip, H2 is the height of the retaining wall structure, H3 is the distance from the first LED chip to the retaining wall structure, and θ ₁ Is the minimum included angle theta between the luminous light of the first LED chip and the plane of the packaging substrate ₂ Is the luminous angle of the LED chip.

When the distance from the first LED chip to the retaining wall structure and the height of the retaining wall structure meet the above relation, the shielding of the retaining wall structure to the LED light is avoided, the light emitting efficiency is improved, the detection precision is improved, the height of the retaining wall structure is minimized, and the PPG packaging module is further reduced.

In some possible implementations, the light emitting module includes at least three LED chips including a red flip LED chip, a green flip LED chip, and an infrared flip LED chip. Of course, the light emitting module may also include other numbers of LED chips, and the types of LED chips are not limited to red flip LED chips, green flip LED chips, and infrared flip LED chips.

In some possible implementations, on the basis that the three LED chips include a red flip LED chip, a green flip LED chip and an infrared flip LED chip, the peak wavelength of the red flip LED chip ranges from 640.0nm to 670.0nm, and the material of the light emitting layer of the red flip LED chip includes aluminum gallium indium phosphorus; the peak wavelength range of the green flip LED chip is 520nm, and the material of the light-emitting layer of the green flip LED chip comprises indium gallium nitride; the peak wavelength range of the infrared flip LED chip is 940nm, and the material of the light emitting layer of the infrared flip LED chip comprises aluminum gallium arsenide.

When the PPG package module includes the three LED chips, the chip level height gain is about 130um, so that the height gain of the PPG package module is about 130 um.

In some possible implementations, the number of light emitting modules is three, and the number of light receiving modules is three; the three light emitting modules and the three light receiving modules are circumferentially arranged in sequence, and a light receiving module is arranged between two adjacent light emitting modules. The layout mode enables each light receiving module to generate a plurality of optical measurement channels, and improves the optical efficiency of the light emitting module. Of course, the layout of the PPG package module 50 is not limited thereto, and one skilled in the art can set the layout according to practical situations.

In some possible implementations, the PPG package module further includes a reflective layer disposed on a sidewall of the retaining wall structure. The arrangement of the reflecting layer can reflect the light signals irradiated to the retaining wall structure, reduce the absorption of the retaining wall structure to the light signals and improve the light-emitting efficiency.

In some possible implementations, the PPG packaging module includes a reflective layer made of a material including Indium Tin Oxide (ITO) coating, diffuse reflection coating, antireflection coating, baSO ₄ Reflective coatings or nano-reflective coatings, and the like.

In some possible implementation manners, on the basis that the three light emitting modules and the three light receiving modules are sequentially circumferentially arranged, the PPG packaging module further comprises a temperature detector and/or a humidity detector; three light emitting modules and three light receiving modules surround the temperature detector and/or the humidity detector.

In some possible implementations, the package substrate includes an epoxy molding compound substrate, a ceramic substrate, an aluminum substrate, a copper substrate, a silicon substrate, or the like.

In a second aspect, an embodiment of the present application provides an electronic device, where the electronic device includes a printed circuit board and the PPG packaging module of the first aspect; the PPG packaging module is arranged on the printed circuit board, and the packaging substrate is electrically connected with the printed circuit board.

Any implementation manner of the second aspect and the second aspect corresponds to any implementation manner of the first aspect and the first aspect, respectively. The technical effects corresponding to the second aspect and any implementation manner of the second aspect may be referred to the technical effects corresponding to the first aspect and any implementation manner of the first aspect, which are not described herein.

In some possible implementations, the electronic device includes a smart wearable device. The intelligent wearable device can be a wearable device capable of supporting human health monitoring, such as an intelligent watch, an intelligent bracelet or an intelligent eye shield. It can be understood that the PPG packaging module provided by the embodiment of the application can also be used in electronic devices such as mobile phones, tablet computers, or the like, and the embodiment of the application is not particularly limited thereto.

Drawings

Fig. 1 is a schematic structural diagram of an electronic device according to an embodiment of the present application;

fig. 2 is a film layer diagram of an electronic device according to an embodiment of the present application;

fig. 3 is a layout diagram of a PPG package module according to an embodiment of the present application;

fig. 4 is a film layer of a PPG package module according to an embodiment of the present application;

fig. 5 is a schematic structural diagram of an LED chip according to an embodiment of the present application;

fig. 6 is a film layer diagram of another PPG package module according to an embodiment of the present application;

fig. 7 is a film layer diagram of another PPG package module according to an embodiment of the present application;

fig. 8 is a film layer diagram of another PPG package module according to an embodiment of the present application;

fig. 9 is a film layer diagram of another PPG package module according to an embodiment of the present application;

fig. 10 shows a schematic structural diagram of the PPG package module in which the LED chips in the PPG package module are vertical LED chips and the LED chips in the PPG package module are flip-chip LED chips;

FIG. 11a shows a simulation of the LED chip in the PPG package module being a vertical LED chip;

fig. 11b shows a simulation of the case where the LED chip in the PPG package module is a flip-chip LED chip.

Detailed Description

The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

The term "and/or" is herein merely an association relationship describing an associated object, meaning that there may be three relationships, e.g., a and/or B, may represent: a exists alone, A and B exist together, and B exists alone.

The terms first and second and the like in the description and in the claims of embodiments of the application, are used for distinguishing between different objects and not necessarily for describing a particular sequential order of objects. For example, the first target object and the second target object, etc., are used to distinguish between different target objects, and are not used to describe a particular order of target objects.

In embodiments of the application, words such as "exemplary" or "such as" are used to mean serving as an example, instance, or illustration. Any embodiment or design described herein as "exemplary" or "e.g." in an embodiment should not be taken as preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "such as" is intended to present related concepts in a concrete fashion.

In the description of the embodiments of the present application, unless otherwise indicated, the meaning of "a plurality" means two or more. For example, the plurality of processing units refers to two or more processing units; the plurality of systems means two or more systems.

At present, PPG modules are often used on smart wearable devices to measure physiological data such as human heart rate and blood oxygen. In order to facilitate control, the intelligent wearable device further comprises a processing module, when the intelligent wearable device works, the processing module drives the LED to emit light signals, after the light signals are transmitted to the skin, one part of the light signals can be absorbed by human tissues (including blood) in the skin, the other part of the light signals can be scattered and reflected, and one part of the scattered and reflected light signals can be received by the PD and converted into electric signals; after receiving the electrical signal output by the PD, the processing module can amplify and sample the electrical signal to obtain a pulse wave signal.

However, the existing PPG module has a large volume and a thick thickness, and the light emitting efficiency of the LED is low, so that the miniaturized design of the intelligent wearable device using the PPG module is not facilitated, and the detection of the PPG is not facilitated.

In order to solve the technical problems, the embodiment of the application provides a PPG packaging module and electronic equipment, wherein the PPG packaging module mainly adopts a flip LED chip, thus, gold wires (wires which are electrically connected with a substrate and are far away from an electrode of the substrate in a vertical LED chip) are not required to be arranged, the reliability of the PPG module is improved, the risk of gold wire breakage in the transportation process and the installation process is reduced, the high of the PPG module caused by gold wire welding is avoided, and meanwhile, the flip PD design is matched, so that the height of the PPG packaging module is reduced. In addition, when the height of the PPG module is reduced, the thickness of the retaining wall structure (a structure for isolating the LEDs from the PD and preventing the light emitted by the LEDs from being directly received by the PD without passing through the skin) is reduced, the light absorption of the side retaining wall structure to the light signals emitted by the LED chip is reduced, the light emitting efficiency of the LEDs is improved, and the detection of the PPG is facilitated.

The PPG packaging module provided by the embodiment of the application can be applied to intelligent wearing equipment, wherein the intelligent wearing equipment can be wearing equipment which can support human health monitoring, such as an intelligent watch, an intelligent bracelet or an intelligent eye shield. It can be understood that the PPG packaging module provided by the embodiment of the application can also be used in electronic devices such as mobile phones, tablet computers, or the like, and the embodiment of the application is not particularly limited thereto. For ease of understanding, the following description will be given by taking the PPG package module as an example applied to the smart watch.

Referring to fig. 1, fig. 1 is a schematic structural diagram of an electronic device according to an embodiment of the present application, and fig. 2 is a film layer diagram of an electronic device according to an embodiment of the present application. As shown in fig. 1 and 2, the smart watch 100 includes a display module 10 and a housing 20, and the housing 20 includes a middle frame 21 and a rear cover 22, wherein the middle frame 21 and the rear cover 22 may be integrally formed or may be separately formed, and the embodiment of the present application is described by taking the middle frame 21 and the rear cover 22 as an example.

The display module 10 and the housing 20 enclose a cavity. The accommodating cavity is internally provided with a printed circuit board (Printed Circuit Board, PCB) 30, a processing module 40, a PPG packaging module 50 and other structures, and the processing module 40 and the PPG packaging module 50 are arranged on the PCB 30. The processing module 40 and the PPG packaging module 50 may be disposed on two opposite sides of the PCB 30, or may be disposed on the same side of the PCB 30, which is not limited in the embodiment of the present application.

Referring to fig. 3 and fig. 4, fig. 3 is a layout diagram of a PPG packaging module according to an embodiment of the present application, and fig. 4 is a film layer of a PPG packaging module according to an embodiment of the present application. As shown in fig. 3 and fig. 4, the PPG package module 50 includes a package substrate 51 and a wall structure 52 located on one side of the package substrate 51, wherein the package substrate 51 is electrically connected to the PCB 30, and the wall structure 52 may include a plurality of hollowed-out portions 521, the hollowed-out portions 521 expose a plurality of areas of the package substrate 51, and each area includes a plurality of pins. For example, the retaining wall structure 52 including the plurality of hollowed-out portions 521 may be disposed on the package substrate 51 by using an adhesive process.

As for the type of the package substrate 51, the embodiment of the present application does not limit the type of the package substrate 51, as long as it can realize electrical connection with the PCB 30, and electrical connection with the light emitting module 53, the light receiving module 54, etc. (described later), and further electrical connection of the light emitting module 53, the light receiving module 54, etc. with the PCB 30. The package substrate 51 includes, for example, an epoxy molding compound (Epoxy Molding Compound, EMC) substrate, a ceramic substrate, an aluminum substrate, a copper substrate, a silicon substrate, or the like.

With continued reference to fig. 3 and 4, the PPG packaging module 50 further includes at least one light emitting module 53 and at least one light receiving module 54. In some embodiments, PPG packaging module 50 may also include other sensors 55, such as at least one of a temperature detector and a humidity detector. The at least one light emitting module 53, the at least one light receiving module 54 and the other sensors 55 are respectively disposed in the plurality of hollowed-out portions 521, and the number of the light emitting modules 53 is three, the number of the light receiving modules 54 is also three, the other sensors 55 are temperature detectors, and the number is one, and accordingly, the retaining wall structure 52 includes seven hollowed-out portions 521, the seven hollowed-out portions 521 expose seven areas of the package substrate 51, the three light emitting modules 53 are respectively disposed in three areas thereof, the three light receiving modules 54 are respectively disposed in the other three areas, and one temperature detector is disposed in the remaining one area. The at least one light emitting module 53, the at least one light receiving module 54 and the other sensors 55 disposed in the plurality of hollowed-out portions 521 are electrically connected with pins of the respective areas to achieve electrical connection with the package substrate 51, and further electrically connected with the PCB 30 through the package substrate 51, so that the processing module 40 disposed on the PCB 30 can achieve electrical connection with the light emitting module 53, the light receiving module 54 and the other sensors 55 through the PCB 30 and the package substrate 51 to conduct signal interaction and transmission. By way of example, the electrical connection of the package substrate 51 with the light emitting module 53, the light receiving module 54 and the other sensors 55 may be achieved by soldering, for example.

Specifically, in operation, the processing module 40 drives the light emitting module 53 to emit a light signal, after the light signal is transmitted to the skin, a part of the light signal is absorbed by human tissue (including blood) in the skin, another part of the light signal is scattered and reflected, and a part of the scattered and reflected light signal is received by the light receiving module 54 and converted into an electrical signal; after receiving the electrical signal output by the light receiving module 54, the processing module 40 may amplify and sample the electrical signal to obtain a pulse wave signal.

Since heart beats of a human body are transferred to skin capillaries through blood vessels, a change in blood volume is caused, wherein when the heart contracts, the blood vessels expand, the blood volume increases, more light signals are absorbed, and scattered signals are reduced; upon diastole, the blood vessels recover, blood volume recovers, the absorbed light signal decreases, and the scattered signal increases. Therefore, the scattered and reflected optical signals will change regularly along with the pulse of the human body, and the pulse wave change condition can be detected based on the change of the electrical signals detected by the optical receiving module 54, so that the data such as heart rate and blood oxygen can be determined based on the pulse wave change condition.

Since the light emitting module 53 and the light receiving module 54 are both located in the hollow portion 521 of the retaining wall structure 52, the light emitting module 53 and the light receiving module 54 can be separated by the area without the hollow portion 521, so that the light signal of the light emitting module 53 is prevented from being directly affected by the light receiving module 54 to affect the detection of the PPG.

The light emitting module 53 includes at least one LED chip. The at least one LED chip comprises at least one of a high-light-efficiency yellow light flip LED chip, a high-light-efficiency green light flip LED chip, a high-light-efficiency blue light flip LED chip, a high-light-efficiency red light flip LED chip, a high-light-efficiency green light flip LED chip, a high-light-efficiency orange light flip LED chip and a high-light-efficiency infrared flip LED chip. Wherein, the peak wavelength range of the yellow flip LED chip is 550.0 nm-579.9 nm, the peak wavelength range of the green flip LED chip is 510.0 nm-549.9 nm, the peak wavelength range of the cyan flip LED chip is 480.0 nm-509.9 nm, the peak wavelength range of the blue flip LED chip is 450.0 nm-479.9 nm, the peak wavelength range of the red flip LED chip is 610.0 nm-699.9.0 nm, the peak wavelength range of the orange flip LED chip is 580.0 nm-609.9 nm, and the peak wavelength range of the infrared flip LED chip is 700.0 nm-1100.0 nm. The type of LED chip (different peak wavelength ranges for different types) can be selected by those skilled in the art according to the actual situation.

The light receiving module 54 may be used to receive the light emitted by the light emitting module 53, and the light receiving module 54 may be a PD, a photo resistor (photo resistor), a photo transistor (photo transistor), a photo converter, etc., and the present application is described taking the light receiving module 54 as a PD.

The light emitting module 53 is a flip-chip light emitting module 53, and the light receiving module 54 is a flip-chip light receiving module 54, that is, when the light emitting module 53 is an LED chip, the LED chip is a flip-chip LED chip, and when the light receiving module 54 is a PD, the PD is a flip-chip PD.

Referring to fig. 5, fig. 5 is a schematic structural diagram of an LED chip according to an embodiment of the present application, where, as shown in fig. 5, the flip-chip LED chip includes a first semiconductor layer 531, a light emitting layer 532, and a second semiconductor layer 533 sequentially disposed away from a package substrate 51; also included are a first electrode 534 and a second electrode 535; wherein the first electrode 534 is located at a side of the first semiconductor layer 531 facing away from the light emitting layer 522; the second electrode 535 is located at a side of the second type semiconductor layer 533 close to the light emitting layer 532.

In addition, the specific materials of the flip LED chip are not specifically limited, that is, the materials of the first type semiconductor layer 531, the light emitting layer 532, and the second type semiconductor layer 533 are not limited in this embodiment, and different materials are selected according to different light emitting colors of the LED chip, for example, materials such as gallium nitride or gallium arsenide may be included.

Because the LED chip in the PPG packaging module 50 provided by the embodiment of the present application is a flip LED chip, that is, the first electrode 534 and the second electrode 535 of the flip LED chip are located on the same side, so that the PPG packaging module can be directly electrically connected with the packaging substrate 51, without arranging a gold wire, and without reserving a pin electrically connected with the gold wire on the packaging substrate 51, the reliability of the PPG module is increased, and the risk of breakage of the gold wire in the transportation process and the installation process is reduced; and avoid the high height of PPG module because gold thread welding leads to and avoid because the area of package substrate 51 that reserves the pin that is connected with gold thread electricity leads to on package substrate 51 is great, and then lead to the size of PPG module on the horizontal plane great, reduce the height of PPG package module to and reduce the size of PPG package module on the horizontal plane. When the PPG packaging module is applied to electronic equipment, especially for intelligent wearing equipment, the miniaturized design of the intelligent wearing equipment is facilitated, so that the requirement of a user on the miniaturization of the electronic equipment is met. In addition, when the PPG module height 50 is reduced, the thickness of the retaining wall structure 52 is reduced, so that the light absorption of the side retaining wall structure 52 to the light signal emitted by the LED chip is reduced, the light emitting efficiency of the LED chip is improved, and the detection precision is improved. In addition, the LED chip and the PD share the packaging substrate 51, so that the whole packaging of the LED chip and the PD is realized, and the reliability of the PPG module height 50 is further improved.

It should be noted that, the layout of the PPG packaging module 50 is not limited in the embodiment of the present application, i.e. the number and the arrangement positions of the light emitting modules 53 and the light receiving modules 54 are not limited.

In a possible implementation manner, with continued reference to fig. 3, the ppg packaging module 50 includes three light emitting modules 53 and three light receiving modules 54, where the three light emitting modules 53 and the three light receiving modules 54 are sequentially circumferentially disposed, and one light receiving module 54 is disposed between two adjacent light emitting modules 53, and one light emitting module 53 is disposed between two adjacent light receiving modules 54.

In this case, in some embodiments, three light emitting modules 53 are uniformly distributed, i.e., the distances between adjacent two light emitting modules 53 are the same, and three light receiving modules 54 are uniformly distributed, i.e., the distances between adjacent two light receiving modules 54 are the same, and the three light emitting modules 53 and the three light receiving modules 54 are located in different orientations. When the PPG package module 50 further includes other detectors 55, three light emitting modules 53 and three light receiving modules 54 are disposed around the other detectors 55. This arrangement allows each light receiving module 54 to create multiple optical measurement paths, improving the optical efficiency of the light emitting module 53.

In addition, the shape of the package substrate 51 may be set according to the shape of the electronic device, and in this example, the electronic device may be circular, and the package substrate 51 may be set to be circular. Alternatively, the package substrate 51 may have other shapes, such as a direction, a diamond shape, etc., which are not listed here.

It should be noted that the number of LED chips included in the light emitting module 53 and the type of LED chips are not limited in the embodiment of the present application.

In one possible implementation, with continued reference to fig. 3, the light emitting module 53 includes three LED chips including a red flip LED chip, a green flip LED chip, and an infrared flip LED chip. The peak wavelength of the red flip-chip LED chip is 640.0nm to 670.0nm, the size is 13 to 14mil, the material of the light emitting layer 532 is aluminum gallium indium phosphide (AlGaInP), and the package substrate 51 is a silicon substrate, a sapphire substrate, or the like. When the red flip LED chip is adopted, the height of the PPG package module 51 can be reduced by about 130 um. The green flip-chip LED chip has a peak wavelength range of 520nm, a size of 19-20mil, for example, and the material of the light emitting layer 532 is indium gallium nitride (InGaN), for example, and the package substrate 51 is a silicon substrate, a sapphire substrate, or the like, for example. When the red flip LED chip is adopted, the height of the PPG package module 51 can be reduced by about 130 um. The peak wavelength range of the infrared flip-chip LED chip is 940nm, the size is 13-14mil, the material of the light emitting layer 532 is aluminum gallium arsenide (AlGaAs), and the package substrate 51 is a silicon substrate or a sapphire substrate, for example. When the infrared flip-chip LED chip is adopted, the height of the PPG package module 51 can be reduced by about 130um, for example. The embodiments of the present application are described taking the example that the light emitting module 53 includes three LED chips.

In order to realize stable electrical connection between the first electrode 534 and the second electrode 535 of the LED chip and the pins of the package substrate 51, refer to fig. 6, and fig. 6 is a film layer diagram of another PPG package module according to an embodiment of the present application. As shown in fig. 6, a first die bonding layer 561 is disposed between the first electrode 534 and the pin of the package substrate 51, a second die bonding layer 562 is disposed between the second electrode 535 and the pin of the package substrate 51, and after the first die bonding layer 561 and the second die bonding layer 562 are cured, electrical connection between the first electrode 534 and the pin of the package substrate 51 and electrical connection between the second electrode 535 and the pin of the package substrate 51 are achieved.

Illustratively, the materials of the first die bond layer 561 and the second die bond layer 562 are both, for example, silver.

Similarly, in order to realize stable electrical connection between the two electrodes of the PD and the pins of the package substrate 51, with continued reference to fig. 6, a third die bonding layer 541 and a fourth die bonding layer 542 are disposed between the two electrodes of the PD and the pins of the package substrate 51, and after the third die bonding layer 541 and the fourth die bonding layer 542 are cured, the two electrodes of the PD are electrically connected with the pins of the package substrate 51.

Illustratively, the materials of the third die bond layer 551 and the fourth die bond layer 552 are both, for example, silver.

Considering that the size of the LED chip is small, and because the first electrode 534 and the second electrode 535 are located on the same layer, when the electrical connection between the first electrode 534 and the pin of the package substrate 51 is achieved through the first die attach layer 561, and the electrical connection between the first electrode 534 and the pin of the package substrate 51 is achieved through the second die attach layer 562, there is a risk of a short circuit between the first die attach layer 561 and the second die attach layer 562, and thus, with continued reference to fig. 6, the first isolation structure 57 is provided between the first electrode 534 and the second electrode 535. The first electrode 534 and the second electrode 535 are isolated by the first isolation structure 57, so that the risk of short circuit caused by migration of silver ions under the action of an electric field after the solidification of the first die bond layer 561 and the second die bond layer 562 is prevented.

In order to prevent the risk of short circuit caused by migration of silver ions along with the action of an electric field after solidification of the crystal-fixing layers corresponding to the two electrodes positioned on the same side of the PD, a second isolation structure 543 is arranged between the two electrodes of the PD. The two electrodes of the PD are isolated by a second isolation structure 543.

The material of the first isolation structure 57 and the second isolation structure 543 is not limited in the embodiment of the present application. Illustratively, the material of the first isolation structure 57 is the same as the material of the second isolation structure 543, and both are plastic. When the material of the first isolation structure 57 and the material of the second isolation structure 543 are formed by the same process, the process steps can be simplified.

In order to improve the light emitting efficiency of the LED chips, with continued reference to fig. 3 and 6, at least one LED chip includes a first LED chip 537, where the first LED chip is the LED chip closest to the wall structure 52 among the at least one LED chip, and the distance H1 between the first LED chip and the wall structure 52 and the height H2 of the wall structure 52 satisfy: tan theta _1＝ (H2-H1)/H3, (180-2 theta) ₁ )＞θ ₂ And H2 > H1; wherein H1 is the height of the first LED chip, H2 is the height of the retaining wall structure 52, H3 is the distance from the first LED chip to the retaining wall structure 52, θ ₁ Is the minimum included angle theta between the luminous light of the first LED chip and the plane of the package substrate 51 ₂ Is the luminous angle of the LED chip. Exemplary, when the light emitting angle of the LED chip is 120 DEG, θ ₁ 30 deg..

When the distance from the first LED chip to the retaining wall structure 52 and the height of the retaining wall structure 52 satisfy the above relationship, the shielding of the retaining wall structure 52 to the LED light is avoided, the light extraction efficiency is improved, and the detection accuracy is improved, meanwhile, the height of the retaining wall structure 52 is minimized, which is beneficial to further reducing the height of the PPG packaging module.

For example, when the light emitting module 53 includes three LED chips, the three LED chips are circumferentially arranged with the same distance from the wall structure 52, and thus, the three LED chips are all the first LED chips.

In order to further improve the light emitting efficiency of the LED chip and prevent the light absorption of the light signal emitted by the LED chip by the retaining wall structure 52, referring to fig. 7, fig. 7 is a film layer diagram of another PPG packaging module according to an embodiment of the present application. As shown in fig. 7, the PPG package module 50 further includes a reflective layer 58 disposed on the sidewall of the wall structure 52. The reflective layer 58 can reflect the light signal emitted to the wall structure 52, so as to reduce the absorption of the light signal by the wall structure 52 and improve the light output efficiency.

As for the material of the reflective layer 58, the material of the reflective layer 58 is not limited in the embodiment of the present application, as long as the light extraction efficiency can be improved. Exemplary materials for the reflective layer 58 include Indium Tin Oxide (ITO) coating, diffuse reflective coating, antireflective coating, baSO ₄ Reflective coatings or nano-reflective coatings, and the like.

In order to further improve the light emitting efficiency of the LED chip, a reflective layer (not shown) is also disposed on the surface of the package substrate 51 (on the side where the LED chip is disposed), and the light signal of the LED chip is reflected by the reflective layer.

When the PPG package module 50 is disposed on the PCB 30, a reflective layer (not shown) is also disposed on the surface of the PCB 30 (on the side where the PPG package module 50 is disposed) to reflect the whole optical signal of the PPG package module 50.

As is clear from the foregoing, by curing the first die bond layer 561 and the second die bond layer 562, the electrical connection of the first electrode 534 and the lead of the package substrate 51, and the electrical connection of the second electrode 535 and the lead of the package substrate 51 are realized.

In this case, considering that external moisture and the like easily permeate into the die bonding layer of the LED chip to cause the risk of short circuit and/or open circuit of the LED chip, referring to fig. 8, fig. 8 is a film layer diagram of another PPG packaging module provided in the embodiment of the present application. As shown in fig. 8, the PPG package module 50 further includes a first encapsulant 59, where the first encapsulant 59 covers at least the first electrode 534 and the second electrode 535 of the LED chip, and covers the first die attach layer 561 and the second die attach layer 562.

The first packaging adhesive 59 is arranged, so that on one hand, the die bonding layer can be protected from external influence, the risk of short circuit caused by migration of anions under the action of an electric field after the die bonding layer is solidified is avoided, and the reliability of the PPG packaging module 50 is greatly improved; on the other hand, the stability of the light type of the LED chip is ensured.

As for the height of the LED chip packaging adhesive 59, the height of the first packaging adhesive 59 is not limited in the embodiment of the present application, as long as the first electrode 534 and the second electrode 535 of the LED chip and the first die attach layer 561 and the second die attach layer 562 can be covered.

In some possible implementations, with continued reference to fig. 8, in the first direction, the height H4 of the first encapsulant 59 is less than the height H5 of the LED chip; wherein the first direction is perpendicular to the package substrate 51.

By the arrangement, the reliability of the PPG packaging module 50 can be greatly improved, the refraction inside the LED chip can be reduced, the light angle of the LED chip is reduced, the light-emitting concentration of the PPG packaging module 50 is ensured, the refraction of light of the subsequent PPG packaging module 50 on the skin of a human body is facilitated, and the absorption of PD to the light is facilitated.

In still another possible implementation manner, referring to fig. 9, fig. 9 is a film layer diagram of another PPG packaging module according to an embodiment of the present application. As shown in fig. 9, along the first direction, the height of the first encapsulation adhesive H4 is greater than the height of the LED chip H5; wherein the first direction is perpendicular to the package substrate 51. That is, the whole LED chip is sealed and protected so as to be suitable for the environment with severe conditions. In this case, in order to further improve the light extraction efficiency, a highly reflective material may be coated on the sidewalls of the wall structures 52 through a spin coating process.

In order to enhance the light extraction efficiency of the LED chip, the refractive index n of the first encapsulation compound 59 satisfies: n is more than or equal to 1.4 and less than or equal to 1.6. Illustratively, n is 1.4, 1.5, 1.6, etc.

As for the material of the first encapsulating compound 59, the material of the first encapsulating compound 59 is not limited in the embodiment of the present application, and may be selected by those skilled in the art according to practical situations. By way of example, the encapsulation compound 59 may comprise, for example, polycarbonate, polymethyl methacrylate, glass, silicone, epoxy, or the like.

In addition, in view of the risk of external moisture and the like penetrating into the die bonding layer of the PD to cause short and/or open circuit of the PD, and with continued reference to fig. 8 or 9, the ppg package module 50 further includes a second encapsulant 544, where the second encapsulant 544 covers at least two electrodes (also referred to as a first electrode and a second electrode) of the PD, and covers the third die bonding layer 541 and the fourth die bonding layer 542.

The second packaging adhesive 544 can protect the third die bonding layer 541 and the fourth die bonding layer 542 from external influence, so as to avoid the risk of short circuit caused by the migration of anions under the action of an electric field after the curing of the die bonding layers, and further improve the reliability of the PPG packaging module 50.

To simplify the process steps, the first and second encapsulants 59 and 544 may be formed using the same process.

In summary, the PPG packaging module provided by the embodiment of the application has lower height, improves the light emitting efficiency, and has more concentrated light patterns; in addition, the PPG packaging module has higher reliability and can be applied to electronic equipment such as watchbands and the like with strict requirements on thickness and reliability.

In order to describe the PPG package module of the present application in detail, the light extraction efficiency can be improved, and the following description will be made by comparing the LED chip in the light emitting module 53 with a vertical LED chip.

Fig. 10 shows a schematic structural diagram of the vertical LED chip of the PPG package module and the flip LED chip of the PPG package module, fig. 11a and 11b show simulation diagrams of the vertical LED chip of the PPG package module and the flip LED chip of the PPG package module, respectively, wherein the simulation diagrams are simulation diagrams of brightness, the left graph in fig. 11a and 11b represents the illuminance of radiation, the lighter the color from bottom to top, the higher the illuminance of radiation, the right graph in fig. 11a and 11b represents one receiving plane (plane receiving light emitted from the LED chip) of 25 (units of inches) by 25 (units of inches), and the color corresponding to each position of the receiving plane represents the illuminance of radiation received by the plane.

Wherein the simulation parameter settings and materials are shown in tables 1 and 2.

Table 1 sets specific values for the simulation parameters.

Structure of the	Reflectivity of	Transmittance of light
			Reflective layer on retaining wall structure	0.88	0.12
Reflective layer on package substrate	0.92	0.08
			Reflective layer on PCB	0.95	0.05

Table 2 shows specific materials for each structure.

Fig. 10 (1) is a schematic structural diagram of an LED chip in the PPG package module, referring to fig. 10 (1), the light emitting module 53 includes a vertical LED chip, the vertical LED chip is electrically connected with the package substrate 51 through a gold wire 60, the thickness of the LED chip is 0.13mm, the distance from the highest point of the gold wire 60 to the package substrate 51 is 0.23mm, the height of the wall structure 52 is 0.33mm, and the thickness of the package substrate 51 is 0.2mm.

Fig. 10 (2) is a schematic structural diagram of an LED chip in the PPG package module, referring to fig. 10 (2), the light emitting module 53 includes a flip LED chip, the thickness of the flip LED chip is 0.13mm, the height of the wall structure 52 is 0.23mm, and the thickness of the package substrate 51 is 0.2mm.

As shown in fig. 11a and 11b, the minimum value, the maximum value, and the average value of the illuminance of radiation in the receiving plane (shown in fig. 11a and 11 b) can be found by simulation, and the luminous flux (light-emitting efficiency) in the determination based on the minimum value, the maximum value, and the average value of the illuminance of radiation in the receiving plane, wherein the total luminous flux is 1. It can be found by comparing the simulation graphs that when the LED chip in the PPG package module is a vertical LED chip, the light-emitting efficiency of the PPG package module 50 is 97.7%, and when the LED chip in the PPG package module is a flip LED chip, the light-emitting efficiency of the PPG package module 50 reaches 99.6%, that is, when the LED chip in the PPG package module is a flip LED chip, and accordingly, the height of the retaining wall structure 52 is reduced, the light-emitting efficiency is improved.

Therefore, through simulation, the PPG packaging module provided by the embodiment of the application can improve the light extraction efficiency while reducing the overall height.

It should be noted that the above values are only for illustration, and the solution of the PPG package module including the flip LED chip in the embodiment of the present application is superior to the PPG package module including the vertical LED chip, and the above values do not limit the present application.

The above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the application.

Claims

1. The utility model provides a PPG encapsulation module which characterized in that includes:

packaging a substrate;

the retaining wall structure is positioned on one side of the packaging substrate; the retaining wall structure comprises a plurality of hollowed-out parts so as to expose a part of the area of the packaging substrate;

The at least one light emitting module and the at least one light receiving module are respectively arranged in the hollowed-out parts and are electrically connected with the packaging substrate;

the light emitting module comprises at least one LED chip, the LED chip is a flip LED chip, and the light receiving module comprises a flip photoelectric detector.

2. The PPG packaging module of claim 1, further comprising a first encapsulant covering at least the first and second electrodes of the LED chip.

3. The PPG packaging module of claim 2, wherein a height of the first encapsulant is less than a height of the LED chip along a first direction;

wherein the first direction is perpendicular to the package substrate.

4. The PPG packaging module of claim 2, wherein a height of the first encapsulant is greater than a height of the LED chip along a first direction;

wherein the first direction is perpendicular to the package substrate.

5. The PPG package module of claim 2, wherein the refractive index n of the first encapsulant satisfies: n is more than or equal to 1.4 and less than or equal to 1.6.

6. The PPG module of claim 5, wherein said first encapsulant comprises polycarbonate, polymethyl methacrylate, glass, silicone or epoxy.

7. The PPG packaging module of any one of claims 1-6, further comprising a second encapsulant covering at least the first and second electrodes of the flip-chip photodetector.

8. The PPG module of claim 7, wherein when the PPG module further comprises a first encapsulant, the first encapsulant and the second encapsulant are formed by the same process.

9. The PPG packaging module of claim 1, wherein a first isolation structure is disposed between the first electrode and the second electrode of the LED chip.

10. The PPG packaging module of claim 1 or 9, wherein a second isolation structure is provided between two electrodes of the flip-chip photodetector.

11. The PPG packaging module of claim 1, wherein at least one LED chip comprises a first LED chip, the first LED chip being the closest LED chip to the dam structure among the at least one LED chip;

the distance between the first LED chip and the retaining wall structure and the height of the retaining wall structure are as follows:

tanθ ₁ = (H2-H1)/H3, (180-2θ) ₁ )＞θ ₂ And H2 > H1;

wherein H1 is the height of the first LED chip, H2 is the height of the retaining wall structure, H3 is the distance from the first LED chip to the retaining wall structure, and θ ₁ For the minimum included angle theta between the luminous light of the first LED chip and the plane of the packaging substrate ₂ Is the luminous angle of the LED chip.

12. The PPG packaging module of claim 1, wherein the light emitting module comprises at least three LED chips including a red flip LED chip, a green flip LED chip, and an infrared flip LED chip.

13. The PPG packaging module of claim 12, wherein the peak wavelength range of the red flip LED chip is 640.0 nm-670.0 nm, and the material of the light emitting layer of the red flip LED chip comprises algalnp;

the peak wavelength range of the green flip LED chip is 520nm, and the material of the light-emitting layer of the green flip LED chip comprises indium gallium nitride;

the peak wavelength range of the infrared flip LED chip is 940nm, and the material of the light emitting layer of the infrared flip LED chip comprises aluminum gallium arsenide.

14. The PPG packaging module of claim 1, wherein the number of light emitting modules is three and the number of light receiving modules is three;

The three light emitting modules and the three light receiving modules are sequentially arranged circumferentially, and one light receiving module is arranged between two adjacent light emitting modules.

15. The PPG module of claim 1, further comprising a reflective layer disposed on a sidewall of the wall structure.

16. The PPG packaging module of claim 15, wherein the reflective layer comprises Indium Tin Oxide (ITO) coating, diffuse reflective coating, antireflective coating, baSO ₄ A reflective coating or a nano-reflective coating.

17. The PPG packaging module of claim 14, further comprising a temperature detector and/or a humidity detector;

three of the light emitting modules and three of the light receiving modules surround the temperature detector and/or the humidity detector.

18. The PPG package module of claim 1, wherein said package substrate comprises an epoxy molding compound substrate, a ceramic substrate, an aluminum substrate, a copper substrate, or a silicon substrate.

19. An electronic device comprising a printed circuit board and the PPG packaging module of any one of claims 1-18;

The PPG packaging module is arranged on the printed circuit board, and the packaging substrate is electrically connected with the printed circuit board.

20. The electronic device of claim 19, wherein the electronic device comprises a smart wearable device.