A vital sign monitoring sensor module and a manufacturing method thereof

Abstract

The application discloses a kind of vital sign monitoring sensor module and preparation method thereof, the module is based on vital sign sensor packaging module support, free-form surface light emitting diode packaging emitter portion is provided in one side thereof, the other side is provided with wide-angle super-structure lens photodetector receiver portion, the LED packaging design of specific smaller angle of green light is realized by free-form surface packaging, so that light energy is more effectively entered into skin tissue, reaches blood vessel network, improves the accuracy and sensitivity of heart rate and blood oxygen sensor. On the other hand, by using the design of wide-angle super-structure lens, the energy of the current bottleneck light green part can be more efficiently collected. Not only can the light rays scattered from the skin at 0° incidence be collected into the photodetector module, but also the light energy of light rays at different angles, even up to 89° incidence, can be collected, and the focal plane remains unchanged. Similarly for red light and infrared light, the super-structure lens also has wide-angle characteristics.

Description

TECHNICAL FIELD

[0001] The present application relates to a vital sign monitoring sensor module, in particular to a vital sign monitoring module based on freeform surface and wide-angle superlens. BACKGROUND

[0002] The LED light used in the current commercial heart rate and blood oxygen saturation vital sign monitoring sensor is generally Lambertian, with a half-angle of emission of about 60°, and the utilization rate of the LED light source is often not high. In engineering practice, the photodetector can be placed on one side of the LED or arranged according to specific needs. Since the dermis contains a rich network of blood vessels, the depth is 400-4000 μm, and the dermal tissue transmits different wavelengths of light to different depths. Longer wavelengths can penetrate deeper into the skin tissue. The longest wavelength used for heart rate and blood oxygen saturation sensors is about 940 nm, and the transmission depth of this wavelength is within about 1500 μm. Since the wavelength of green light is short, it can penetrate a relatively thin layer of human skin. Combined with the actual engineering needs, it is often necessary to increase the luminous flux of the green LED. Therefore, it is necessary to explore a green LED emitter with a smaller angle to make the green light energy more concentrated, so as to improve the effective light intensity of the green light. Compared with the traditional Lambertian green LED, the green LED emitter with a smaller angle has a larger luminous flux and contains more photon energy after the module glass windowing, which means that the light intensity reflected on the human skin is greater. The light intensity through the medium is exponentially attenuated with the light path length and the light absorption coefficient of the medium, which means that the light energy of the green LED emitter with a smaller angle can reach deeper blood vessels compared with the Lambertian LED, which has the potential to achieve higher detection accuracy, or under the same level of detection accuracy, the chip's light power can be reduced, thereby reducing the cost. SUMMARY

[0003] Technical problem: The purpose of the present application is to provide a vital sign monitoring sensor module and a preparation method thereof. The vital sign monitoring packaging module based on freeform surface and super surface designed in the present application improves the LED emitter to a small-angle square spot freeform surface design, and improves the glass cover plate of the photodetector to a wide-angle superlens based on a glass substrate. The module includes a green light emitting diode and a freeform surface molded silica gel lens, a red light emitting diode, an infrared light emitting diode, and a photodetector wide-angle superlens packaging four-in-one module.

[0004] Technical solution: The vital sign monitoring sensor module of the present application is based on a vital sign sensor packaging module support, a free-form surface light emitting diode packaging emitter part is arranged on one side in the vital sign sensor packaging module support, a light emitting diode die is arranged on the upper side in the free-form surface light emitting diode packaging emitter part, a free-form surface silica gel lens is formed by mold pressing on the surface of the light emitting diode die, and a glass window is arranged on the groove on the surface of the vital sign sensor packaging module support in front of the light emitting diode die; the light emitting diode die is connected with the positive and negative electrodes of the vital sign sensor packaging module support through the positive and negative electrodes of the diode bonding wire; a wide-angle super-structure lens photodetector receiver part is arranged on the other side in the vital sign sensor packaging module support, a photodetector die is arranged on the upper side in the wide-angle super-structure lens photodetector receiver part, and a wide-angle super-structure lens is arranged on the groove on the surface of the vital sign sensor packaging module support in front of the photodetector die; the photodetector die is connected with the positive and negative electrodes of the vital sign sensor packaging module support through the positive and negative electrodes of the photodetector bonding wire.

[0005] The light emitting diode die includes a green light diode die, a red light diode die and an infrared diode die.

[0006] The green light diode die, the red light diode die and the infrared diode die are connected in the vital sign sensor packaging module support through die bonding glue, tin paste or eutectic solder.

[0007] The surface of the photodetector die is coated with a silica gel layer.

[0008] The photodetector die is connected in the vital sign sensor packaging module support through die bonding glue, tin paste or eutectic solder.

[0009] The free-form surface silica gel lens formed on the surface of the light emitting diode die has a light emitting angle less than or equal to 45°.

[0010] The wide-angle super-structure lens adopts artificial nano-structure material titanium dioxide, wherein the diameter of the titanium dioxide is not equal to 20nm-300nm, and the height of the titanium dioxide microstructure is in the range of 400nm-700nm.

[0011] The distance D from the geometric center of the light emitting diode die to the geometric center of the photodetector die needs to be at least greater than 0.25mm.

[0012] The phase distribution of the nano-pillar array at different positions on the super-structure lens layer is:

[0013]

[0014] wherein k0 is the wave vector in free space, f is the corresponding focal length, r is an arbitrary distance from a super unit to the center of the super lens, and r is in the range of [0, 2f]; it is assumed that the incident collimated light beam is located in the xz plane, and the angle between the lens normal and the lens is θ, wherein k0xsinθ is the gradient phase caused by the oblique incidence, x is the horizontal coordinate of the super lens, and y is the vertical coordinate of the super lens.

[0015] A preparation method of a vital sign monitoring sensor module of the present application: the vital sign monitoring sensor module is a free-form surface and wide-angle super lens vital sign monitoring module, which is installed with a glass window on the free-form surface light-emitting diode package emitter part after the standard wire bonding 4, 6 process is completed, and a wide-angle super lens is installed on the photodetector receiver part of the wide-angle super lens, and the specific steps are as follows:

[0016] Step 1, selection of light-emitting diode chip: the main wavelength of the green chip is between 525 nm and 535 nm, the main wavelength of the red light is about 660 nm, and the main wavelength of the infrared chip is between 935 nm and 945 nm;

[0017] Step 2, selection of photodetector chip: the photodetector is a PIN photodiode or a phototriode;

[0018] Step 3, cleaning support: the vital sign sensor package module support is cleaned by adopting the method of plasma cleaning or the method of ultrasonic cleaning;

[0019] Step 4, die bonding: the die bonding is performed by adopting manual or automatic die bonder, and all the chips are connected on the vital sign sensor package module support by adopting the method of silver glue, tin paste or eutectic soldering;

[0020] Step 5, wire bonding: the diode bonding wire is used to connect the light-emitting diode chip and the vital sign sensor package module support by adopting the method of gold wire ball welding or aluminum wire ultrasonic welding, or the method of copper wire or silver wire bonding; the detector bonding wire is used to connect the photodetector chip and the vital sign sensor package module support;

[0021] Step 6, free-form surface silica gel lens: the free-form surface small-angle silica gel lens is formed by adopting the method of molding;

[0022] Step 7, preparation of wide-angle super lens: the high aspect ratio titanium dioxide nanocolumns are prepared on the silicon dioxide substrate by adopting the method of nanoimprinting;

[0023] Step 8, pasting of wide-angle super lens: the wide-angle super lens is picked up, aligned and placed by adopting the high-precision die bonder.

[0024] Beneficial effects: the vital sign monitoring module based on free-form surface and wide-angle super lens provided by the application adopts super lens to focus light, so that more light can be collected in a limited volume of consumer electronics. At the same time, since the skin is a turbid and inhomogeneous optical medium, the light will be strongly scattered during its propagation, so that the light incident on the surface of the detector may exist in various angles, and the current commercial photodetector module generally uses flat glass, and the outgoing light also exists in various angles. In order to collect more light on a smaller photodetector area, a super lens that can collect various incident light angles is designed to replace the flat glass, thereby forming a new architecture of heart rate and blood oxygen sensor module. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a vital sign monitoring sensor module structure schematic diagram.

[0026] Figure 2 It is a wide-angle super lens structure schematic diagram.

[0027] In the figure: free-form surface LED package emitter part 1, LED die 2, free-form surface silica gel lens 21, vital sign sensor package module support 3, diode bonding wire 4, subcutaneous tissue 5, detector bonding wire 6, photodetector die 7, silica gel layer 71, glass window 8, wide-angle super lens 9, wide-angle super lens photodetector receiver part 10. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings Figure 1 The application will be further described in detail.

[0029] Reference Figure 1As shown, the vital sign monitoring sensor module of the present application is based on a vital sign sensor package module support 3, a free-form surface light emitting diode package emitter part 1 is arranged on one side in the vital sign sensor package module support 3, a light emitting diode die 2 is arranged on the upper side in the free-form surface light emitting diode package emitter part 1, a free-form surface silica gel lens 21 is formed by mold pressing on the surface of the light emitting diode die 2, and a glass window 8 is arranged on the groove on the surface of the vital sign sensor package module support 3 in front of the light emitting diode die 2; the light emitting diode die 2 is connected to the positive and negative electrodes of the vital sign sensor package module support 3 through the positive and negative electrodes of the diode bonding wire 4; a wide-angle super-structured lens photodetector receiver part 10 is arranged on the other side in the vital sign sensor package module support 3, a photodetector die 7 is arranged on the upper side in the wide-angle super-structured lens photodetector receiver part 10, and a wide-angle super-structured lens 9 is arranged on the groove on the surface of the vital sign sensor package module support 3 in front of the photodetector die 7; the photodetector die 7 is connected to the positive and negative electrodes of the vital sign sensor package module support 3 through the positive and negative electrodes of the photodetector bonding wire 6. The light emitting diode die 2 includes green light diode dies, red light diode dies, and infrared diode dies. The light emitted by the emitter is received from the subcutaneous tissue 5 and focused on the surface of the photodetector chip.

[0030] The vital sign monitoring module can monitor the heart rate and blood oxygen concentration of the human body.

[0031] The super-structured lens is a wide-angle super-structured lens, the substrate of the super-structured lens is silicon dioxide, and the nano-structured material is titanium dioxide. The received visible light, green light, red light, and infrared light are respectively focused on the chip surfaces of the respective color detectors through the wide-angle super-structured lens.

[0032] Further, the phase distribution of the nano-pillar array at different positions on the super-structured lens layer is

[0033]

[0034] wherein k0 is the wave vector in free space, f is the corresponding focal length, r is an arbitrary distance from a super-structured unit to the center of the super-structured lens, θ is the angle between the incident collimated light beam and the optical axis of the lens, k0xsinθ is the gradient phase caused by oblique incidence, x is the horizontal coordinate of the super-structured lens, and y is the vertical coordinate of the super-structured lens. The last term of the formula is independent of the position coordinate r, so the oblique incident light undergoes secondary phase modulation, and the light spot in the x direction is shifted by -fsinθ, but the focal length does not change.

[0035] The green light diode chip, red light diode chip, and infrared diode chip are connected in the vital sign sensor packaging module support through the die bonding glue or tin paste or eutectic solder. The surface of the photodetector chip 7 is coated with a silica gel layer 71. The photodetector chip 7 is connected in the vital sign sensor packaging module support 3 through the die bonding glue or tin paste or eutectic solder. The free-form surface silica gel lens 21 formed by mold pressing on the surface of the light-emitting diode chip 2 has a light-emitting angle less than or equal to 45°. The wide-angle superlens 9 adopts artificial nano-structured material titanium dioxide, wherein the diameter of the titanium dioxide is different from 20 nm to 300 nm, and the height of the titanium dioxide microstructure ranges from 400 nm to 700 nm. The distance D from the geometric center of the light-emitting diode chip 2 to the geometric center of the photodetector chip 7 needs to be at least greater than 0.25 mm.

[0036] The vital sign monitoring sensor module of the present application is a free-form surface and wide-angle superlens vital sign monitoring module, which is a free-form surface light-emitting diode packaging emitter part 1 after the completion of the standard wire bonding 4, 6 process, a glass window 8 is installed on the surface of the free-form surface light-emitting diode packaging emitter part 1, and a wide-angle superlens 9 is installed on the wide-angle superlens photodetector receiver part 10. The specific steps are as follows:

[0037] Step 1, selection of the light-emitting diode chip 2, the green chip main wavelength is between 525 nm and 535 nm, the red light main wavelength is around 660 nm, and the infrared chip main wavelength is between 935 nm and 945 nm;

[0038] Step 2, selection of the photodetector chip 7, the light detector is a PIN photodiode or a phototriode;

[0039] Step 3, cleaning the support: adopting the way of plasma cleaning or the way of ultrasonic cleaning to clean the vital sign sensor packaging module support 3;

[0040] Step 4, die bonding, adopting the way of manual or automatic die bonder to bond the die, adopting the way of silver glue, tin paste, or eutectic solder to connect all the chips through the die bonding glue or tin paste or eutectic solder on the vital sign sensor packaging module support 3;

[0041] Step 5, wire bonding, adopting the way of gold wire ball welding or aluminum wire ultrasonic welding, or adopting the way of copper wire or silver wire bonding to connect the light-emitting diode chip 2 and the vital sign sensor packaging module support 3 with the diode bonding wire 4, and to connect the photodetector chip 7 and the vital sign sensor packaging module support 3 with the detector bonding wire 6;

[0042] Step 6, the free-form surface silica gel lens 21 is formed in the way of mold pressing to form a free-form surface small-angle silica gel lens;

[0043] Step 7: Preparation of wide-angle meta-lens 9 by nanoimprinting to prepare titanium dioxide nanorods with high aspect ratio on a silicon dioxide substrate;

[0044] Step 8: Pasting of the wide-angle meta-lens. A high-precision die-bonding machine is used to pick up, align, and place the wide-angle meta-lens 9.

[0045] The photodetector module parts of general wearable devices are in close contact with the wrist. However, the current packaging modules often lack green light energy, so packaging manufacturers will use multiple green light chips to increase the luminous flux of the green light of the packaging module. Some system integration manufacturers even need to purchase separate green light LEDs to enhance the luminous flux of green light, which not only increases the cost but also increases the volume of the module. To address this problem, the present invention adopts a free-form surface lens packaging method to achieve a green light specific smaller angle LED packaging design, so that the light energy can more effectively enter the skin tissue and reach the vascular network, which will improve the accuracy and sensitivity of the heart rate and blood oxygen sensors. At the same time, the wide-angle metasurface lens can also collect and focus incident light at a large angle onto the photodetector, thereby further improving the sensitivity and accuracy of the vital signs monitoring module.

[0046] The above content described in this specification is merely an example of the module structure and preparation method of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described embodiments, as long as they do not deviate from the structure and features of the present invention or exceed the scope defined in this patent document. Such modifications, additions, or substitutions may be made to the described embodiments. As long as such modifications and additions do not deviate from the structure and features of the present invention or exceed the scope defined in this patent document, such modifications and substitutions shall be included within the scope of protection of the present invention.

Claims

1. A vital signs monitoring sensor module, characterized by: The module is based on a vital sign sensor packaging module support (3), a free-form surface LED package emitter part (1) is arranged on one side in the vital sign sensor packaging module support (3), a LED die (2) is arranged on the upper side in the free-form surface LED package emitter part (1), a free-form surface silica gel lens (21) is formed by surface molding on the LED die (2), a glass window (8) is arranged on the groove on the surface of the vital sign sensor packaging module support (3) on the front of the LED die (2); the LED die (2) is connected to the positive and negative electrodes of the vital sign sensor packaging module support (3) through the positive and negative electrodes of the diode bonding wire (4) respectively; a wide-angle superlens photodetector receiver part (10) is arranged on the other side in the vital sign sensor packaging module support (3), a photodetector die (7) is arranged on the upper side in the wide-angle superlens photodetector receiver part (10), a wide-angle superlens (9) is arranged on the groove on the surface of the vital sign sensor packaging module support (3) on the front of the photodetector die (7), and the photodetector die (7) is connected to the positive and negative electrodes of the vital sign sensor packaging module support (3) through the positive and negative electrodes of the photodetector bonding wire (6) respectively.

2. The vital signs monitoring sensor module of claim 1, wherein: The LED die (2) comprises a green light diode die, a red light diode die and an infrared diode die.

3. The vital signs monitoring sensor module of claim 2, wherein: The green light diode die, the red light diode die and the infrared diode die are connected in the vital sign sensor packaging module support (3) through die bonding glue, tin paste or eutectic solder.

4. The vital signs monitoring sensor module of claim 1, wherein: The surface of the photodetector die (7) is coated with a silica gel layer (71).

5. The vital signs monitoring sensor module of claim 4, wherein: The photodetector die (7) is connected in the vital sign sensor packaging module support (3) through die bonding glue, tin paste or eutectic solder.

6. The vital signs monitoring sensor module of claim 2, wherein: The free-form surface silica gel lens (21) formed on the surface of the LED die (2) has a light emitting angle less than or equal to 45°.

7. The vital signs monitoring sensor module of claim 1, wherein: The wide-angle superlens (9) adopts artificial nano-structured material titanium dioxide, wherein the diameter of the titanium dioxide is not equal to 20nm to 300nm, and the height of the titanium dioxide microstructure is in the range of 400nm to 700nm.

8. The vital signs monitoring sensor module of claim 2, wherein: The distance D from the geometric center of the LED die (2) to the geometric center of the photodetector die (7) needs to be at least greater than 0.25mm.

9. The vital signs monitoring sensor module of claim 1, wherein: The phase distribution of the nano-pillar array at different positions on the superlens layer of the wide-angle superlens (9) is as follows: wherein k0 is the wave vector in free space, f is the corresponding focal length, r is the distance from any one super unit to the center of the superlens, θ is the angle between the incident collimated beam and the lens principal axis, k0xsinθ is the gradient phase caused by oblique incidence, x is the horizontal coordinate of the superlens, and y is the vertical coordinate of the superlens.

10. A method of manufacturing a vital signs monitoring sensor module according to any one of claims 1-9, characterized by: The vital sign monitoring sensor module is a free-form surface and wide-angle superlens vital sign monitoring module, glass window (8) is installed on the free-form surface light emitting diode package transmitter part (1) after the completion of standard wire bonding 4, 6 process, wide-angle superlens photodetector receiver part (10) is installed wide-angle superlens (9), the specific steps are: Step 1, the selection of light emitting diode chip (2), the green light chip main wavelength is between 525nm to 535nm, the red light main wavelength is about 660nm, the infrared chip main wavelength is between 935nm to 945nm; Step 2, the selection of photodetector chip (7), the light detector is PIN photodiode or phototriode; Step 3, cleaning support: adopt the way of plasma cleaning, or adopt the way of ultrasonic cleaning to clean the vital sign sensor package module support (3); Step 4, die bonding, adopt manual or automatic die bonder to bond die, adopt the way of point silver glue, solder paste or eutectic solder to connect all chips on the vital sign sensor package module support (3) through die bonding glue or solder paste or eutectic solder; Step 5, wire bonding, adopt the way of gold wire ball welding or aluminum wire ultrasonic welding, or adopt the way of copper wire or silver wire bonding to connect diode bonding wire (4) to connect light emitting diode chip (2), vital sign sensor package module support (3), and connect photodetector bonding wire (6) to connect photodetector chip (7), vital sign sensor package module support (3); Step 6, free-form surface silica gel lens (21) adopts the way of molding to form free-form surface small angle silica gel lens; Step 7, the preparation of wide-angle superlens (9) adopts the way of nanoimprint to realize the preparation of high aspect ratio titanium dioxide nanocolumn on the silicon dioxide substrate; Step 8, the sticking of wide-angle superlens, adopt high-precision die bonder to pick up, align and place wide-angle superlens (9).

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