Vital sign monitoring sensor module and preparation method thereof

Abstract

The invention discloses a vital sign monitoring sensor module and a preparation method thereof.The module 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 module, and a wide-angle super-structure lens photoelectric detector receiver part is arranged on the other side in the module; the LED packaging design of green light with a small specific angle is achieved in a free-form surface packaging mode, so that light energy enters skin tissue more effectively and reaches a blood vessel network, and the accuracy and sensitivity of the heart rate and blood oxygen sensor are improved. And on the other hand, the design of the wide-angle super-structure lens is adopted, so that the energy of the green light part of the current bottleneck light can be more efficiently collected, not only can the light which is scattered from the skin and is incident to the photoelectric detector module at 0 degree be collected, but also the light energy of the incident light at different angles and even 89 degrees can be collected, and the focal plane is kept unchanged. Similarly, for red light and infrared light, the super-structure lens also has the wide-angle characteristic.

Description

Technical Field

[0001] The invention relates to a vital sign monitoring sensor module, in particular to a vital sign monitoring module based on a free-form surface and a wide-angle meta-lens. Background Art

[0002] The LED used in the current commercial heart rate and blood oxygen saturation vital sign monitoring sensors generally emits Lambertian light, with a half-angle of about 60°, and the utilization rate of LED light sources 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 400-4000μm, and the dermis has different transmission depths for different wavelengths of light. Longer wavelengths can penetrate deeper into the skin tissue. The longest wavelength used for heart rate and blood oxygen saturation sensors is about 940nm, and the wavelength transmission depth is within about 1500μm. Since the wavelength of green light is short and the thickness of human skin that can be penetrated is thin, combined with actual engineering needs, it is often necessary to increase the luminous flux of green LEDs. Therefore, it is necessary to explore green LED emitters at smaller angles to make the green light energy more concentrated to increase the effective light intensity of green light. Compared with traditional Lambertian green LEDs, green LED emitters with smaller angles have greater luminous flux after passing through the module glass window when the luminous flux is the same, and contain more photon energy, which is reflected on the human skin, that is, the light intensity is greater. The light intensity passing through the medium decays exponentially with the medium's absorption coefficient and optical path length, which means that green LED emitters with small angles can reach deeper vascular networks than Lambertian LEDs, making it possible to achieve higher levels of detection accuracy, or at the same level of detection accuracy, the optical power of the chip can be reduced, thereby reducing costs. Summary of the invention

[0003] Technical problem: The purpose of the present invention is to provide a vital sign monitoring sensor module and its preparation method. The vital sign monitoring package module designed by the present invention based on free-form surface and meta-structure surface improves the LED emitter into a small-angle square spot free-form surface design, and improves the glass cover of the photodetector into a wide-angle meta-structure lens based on a glass substrate, compared with the traditional commercial module. It includes a green light emitting diode and a free-form surface molded silicone lens, a red light emitting diode, an infrared light emitting diode, and a photodetector wide-angle meta-structure lens package four-in-one module.

[0004] Technical solution: A vital sign monitoring sensor module of the present invention is based on a vital sign sensor packaging module bracket, a free-form surface light-emitting diode packaging transmitter part is provided on one side of the vital sign sensor packaging module bracket, a light-emitting diode die is provided on the upper side of the free-form surface light-emitting diode packaging transmitter part, a free-form surface silicone lens is molded on the surface of the light-emitting diode die, and a glass window is provided on the groove on the surface of the vital sign sensor packaging module bracket on the front side of the light-emitting diode die; the light-emitting diode die is connected to the positive and negative electrodes of the vital sign sensor packaging module bracket through the positive and negative electrodes of the diode bonding wire respectively; a wide-angle meta-lens photodetector receiver part is provided on the other side of the vital sign sensor packaging module bracket, a photodetector die is provided on the upper side of the wide-angle meta-lens photodetector receiver part, a wide-angle meta-lens is provided on the groove on the surface of the vital sign sensor packaging module bracket on the front side of the photodetector die, and the photodetector die is connected to the positive and negative electrodes of the vital sign sensor packaging module bracket through the positive and negative electrodes of the detector bonding wire respectively.

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

[0006] The green light diode tube core, the red light diode tube core, and the infrared diode tube core are connected in the vital sign sensor packaging module bracket through a solid crystal glue or solder paste or eutectic solder.

[0007] The surface of the photoelectric detector core is coated with a silica gel layer.

[0008] The photoelectric detector die is connected to the vital sign sensor packaging module bracket through die bonding glue, solder paste or eutectic solder.

[0009] The free-form silicone lens formed by molding on the surface of the LED core has a light-emitting angle of less than or equal to 45°.

[0010] The wide-angle meta-lens adopts titanium dioxide, an artificial nanostructured material, wherein the diameter of titanium dioxide ranges from 20nm to 300nm, and the height of the titanium dioxide microstructure ranges from 400nm to 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 0.25 mm.

[0012] The phase distribution of the nanocolumn arrays at different positions on the wide-angle metalens layer is:

[0013]

[0014] Wherein, k0 is the wave vector in free space, f is the corresponding focal length, r∈[0,2f] is the distance from any metastructure unit to the center of the metastructure lens; suppose the incident collimated light beam is located in the xz plane, and the angle with the normal axis of the lens is θ, where k0xsinθ is the gradient phase caused by oblique incidence, x is the horizontal coordinate of the metastructure lens, and y is the vertical coordinate of the metastructure lens.

[0015] A method for preparing a vital sign monitoring sensor module of the present invention: the vital sign monitoring sensor module is a vital sign monitoring module of a free-form surface and a wide-angle meta-lens, a glass window is installed on the free-form surface light-emitting diode package transmitter part after the standard wire bonding 4, 6 process is completed, and a wide-angle meta-lens is installed on the wide-angle meta-lens photodetector receiver part, and the specific steps are:

[0016] Step 1: Select the LED chip. The main wavelength of the green light chip is between 525nm and 535nm, the main wavelength of the red light is around 660nm, and the main wavelength of the infrared chip is between 935nm and 945nm.

[0017] Step 2, selection of a photodetector die, the photodetector being a PIN photodiode or a phototransistor;

[0018] Step 3, cleaning the bracket: using plasma cleaning or ultrasonic cleaning to clean the bracket of the vital sign sensor packaging module;

[0019] Step 4, bonding the crystal, using manual or automatic bonding machine to bond the crystal, using silver glue, solder paste, or eutectic welding to connect all the dies to the vital sign sensor package module bracket through bonding glue, solder paste, or eutectic solder;

[0020] Step 5, wire bonding, using gold wire ball welding or aluminum wire ultrasonic welding, or copper wire or silver wire bonding to connect the light-emitting diode die and the vital sign sensor package module bracket with diode bonding wire, and use detector bonding wire to connect the photodetector die and the vital sign sensor package module bracket;

[0021] Step 6, the free-form surface silicone lens is formed into a free-form surface small-angle silicone lens by molding;

[0022] Step 7, the wide-angle meta-lens is prepared by nanoimprinting to prepare titanium dioxide nanorods with high aspect ratio on a silicon dioxide substrate;

[0023] Step 8: Paste the wide-angle meta-lens using a high-precision die-bonding machine to pick up, align and place the wide-angle meta-lens.

[0024] Beneficial effects: The vital signs monitoring module based on free-form surfaces and wide-angle meta-lenses proposed in the present invention uses meta-lenses to focus light, so that more light can be collected within the limited volume of consumer electronic products. At the same time, because the skin is a turbid and inhomogeneous optical medium, light will be strongly scattered during its propagation, so that the light incident on the detector surface may exist at various angles, and current commercial photodetector modules generally use flat glass, and the outgoing light also exists at various angles. In order to collect more light on a smaller photodetector area, a meta-lens that can collect various incident light angles is designed to replace the flat glass, thereby forming a new architecture for the heart rate and blood oxygen sensor module. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The figure is a schematic diagram of the structure of a vital signs monitoring sensor module.

[0026] Figure 2 Schematic diagram of the structure of the wide-angle meta-lens of the present invention.

[0027] The figure includes: free-form surface light-emitting diode package transmitter part 1, light-emitting diode core 2, free-form surface silicone lens 21, vital sign sensor package module bracket 3, diode bonding wire 4, subcutaneous tissue 5, detector bonding wire 6, photodetector core 7, silicone layer 71, glass window 8, wide-angle meta-lens 9, wide-angle meta-lens photodetector receiver part 10. DETAILED DESCRIPTION

[0028] The following is combined with Figure 1 The present invention is described in further detail.

[0029] See also Figure 1As shown, a vital sign monitoring sensor module of the present invention is based on a vital sign sensor package module bracket 3, a free-form surface light emitting diode package emitter part 1 is provided on one side of the vital sign sensor package module bracket 3, a light emitting diode tube core 2 is provided on the upper side of the free-form surface light emitting diode package emitter part 1, a free-form surface silicone lens 21 is molded on the surface of the light emitting diode tube core 2, and a glass window 8 is provided on the groove on the surface of the vital sign sensor package module bracket 3 on the front side of the light emitting diode tube core 2; the light emitting diode tube core 2 is connected to the light emitting diode tube core 2 by a diode bonding wire 4. The positive and negative electrodes are connected to the positive and negative electrodes of the vital sign sensor package module support 3 respectively; a wide-angle meta-lens photodetector receiver part 10 is provided on the other side of the vital sign sensor package module support 3, a photodetector tube core 7 is provided on the upper side of the wide-angle meta-lens photodetector receiver part 10, and a wide-angle meta-lens 9 is provided on the groove on the surface of the vital sign sensor package module support 3 on the front of the photodetector tube core 7. The positive and negative electrodes of the photodetector tube core 7 are connected to the positive and negative electrodes of the vital sign sensor package module support 3 respectively through the detector bonding wire 6. The light emitting diode tube core 2 includes a green light diode tube core, a red light diode tube core, and an infrared diode tube core. The light from the transmitter is received from the subcutaneous tissue 5 and focused on the surface of the photodetector chip.

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

[0031] The meta-lens is a wide-angle meta-lens. The substrate of the meta-lens is silicon dioxide, and the nanostructure material is titanium dioxide. The received visible green light, red light, and infrared light are respectively focused onto the chip surfaces of detectors of various colors through the wide-angle meta-lens.

[0032] Furthermore, the phase distribution of the nanorod arrays at different positions on the metalens layer is:

[0033]

[0034] Where k0 is the wave vector in free space, f is the corresponding focal length, r∈[0,2f] is the distance from any metastructure unit to the center of the metastructure lens; suppose the incident collimated light beam is located in the xz plane, and the angle between it and the normal axis of the lens is θ, where k0xsinθ is the gradient phase caused by oblique incidence, x is the horizontal coordinate of the metastructure lens, and y is the vertical coordinate of the metastructure lens. The last term of the formula is independent of the position coordinate r. Therefore, after the oblique incident light is subjected to secondary phase modulation, the spot has a lateral offset of -fsinθ in the x direction, while the focal length does not change.

[0035] The green light diode die, the red light diode die, and the infrared diode die are connected to the vital sign sensor package module bracket through solid crystal glue, solder paste, or eutectic solder. The surface of the photodetector die 7 is coated with a silicone layer 71. The photodetector die 7 is connected to the vital sign sensor package module bracket 3 through solid crystal glue, solder paste, or eutectic solder. The free-form silicone lens 21 molded on the surface of the light-emitting diode die 2 has a light-emitting angle less than or equal to 45°. The wide-angle meta-lens 9 uses an artificial nanostructured material titanium dioxide, wherein the diameter of titanium dioxide ranges from 20nm to 300nm, and the height of the titanium dioxide microstructure ranges from 400nm to 700nm. The distance D from the geometric center of the light-emitting diode die 2 to the geometric center of the photodetector die 7 needs to be at least greater than 0.25mm.

[0036] The vital sign monitoring sensor module of the present invention is a free-form surface and wide-angle meta-lens vital sign monitoring module. The free-form surface and wide-angle meta-lens vital sign monitoring module is a free-form surface light-emitting diode package transmitter part 1 after the standard wire bonding 4, 6 process is completed, and a glass window 8 is installed on the wide-angle meta-lens photodetector receiver part 10. The specific steps are:

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

[0038] Step 2, selecting the photodetector die 7, the photodetector is a PIN photodiode or a phototransistor;

[0039] Step 3, cleaning the bracket: cleaning the vital sign sensor package module bracket 3 by plasma cleaning or ultrasonic cleaning;

[0040] Step 4, bonding the crystal, using manual or automatic bonding machine to bond the crystal, using silver glue, solder paste, or eutectic welding to connect all the dies to the vital sign sensor package module bracket 3 through bonding glue, solder paste, or eutectic solder;

[0041] Step 5, wire bonding, using gold wire ball welding or aluminum wire ultrasonic welding, or copper wire or silver wire bonding to connect the light-emitting diode die 2 and the vital sign sensor package module bracket 3 with a diode bonding wire 4, and connecting the photodetector die 7 and the vital sign sensor package module bracket 3 with a detector bonding wire 6;

[0042] Step 6, the free-form surface silicone lens 21 is formed into a free-form surface small-angle silicone lens by molding;

[0043] Step 7, the wide-angle meta-lens 9 is prepared 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, using a high-precision die-bonding machine 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 the 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. In response to 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 collect and focus the incident light at a large angle on the photodetector, thereby further improving the sensitivity and accuracy of the vital signs monitoring module.

[0046] The above contents described in this specification are merely examples of the module structure and preparation method of the present invention. Those skilled in the art of the present invention may make various modifications or additions to the specific embodiments described or replace them in a similar manner, and as long as they do not deviate from the structure and features of the present invention or exceed the scope defined in this right, they shall be included in the protection scope of the present invention.

Claims

1. A vital signs monitoring sensor module, characterized in that: The module is based on a vital sign sensor package module support (3), a free-form surface light emitting diode package emitter part (1) is provided on one side of the vital sign sensor package module support (3), a light emitting diode tube core (2) is provided on the upper side of the free-form surface light emitting diode package emitter part (1), a free-form surface silicone lens (21) is formed by molding on the surface of the light emitting diode tube core (2), and a glass window (8) is provided on the groove on the surface of the vital sign sensor package module support (3) on the front side of the light emitting diode tube core (2); the light emitting diode tube core (2) is connected to the positive and negative electrodes of the light emitting diode tube core (2) through the diode bonding wire (4) respectively. The positive and negative electrodes of the vital sign sensor package module support (3) are connected; a wide-angle meta-lens photodetector receiver part (10) is provided on the other side of the vital sign sensor package module support (3); a photodetector tube core (7) is provided on the upper side of the wide-angle meta-lens photodetector receiver part (10); a wide-angle meta-lens (9) is provided on the groove on the surface of the vital sign sensor package module support (3) on the front side of the photodetector tube core (7); and the positive and negative electrodes of the photodetector tube core (7) are respectively connected to the positive and negative electrodes of the vital sign sensor package module support (3) through detector bonding wires (6).

2. A vital sign monitoring sensor module according to claim 1, characterized in that: The light emitting diode die (2) comprises a green light diode die, a red light diode die and an infrared diode die.

3. A vital sign monitoring sensor module according to claim 2, characterized in that: The green light diode tube core, the red light diode tube core and the infrared diode tube core are connected in the vital sign sensor packaging module bracket (3) via a solid crystal glue or solder paste or eutectic solder.

4. A vital sign monitoring sensor module according to claim 1, characterized in that: The surface of the photodetector tube core (7) is coated with a silica gel layer (71).

5. A vital sign monitoring sensor module according to claim 4, characterized in that: The photoelectric detector tube core (7) is connected to the vital sign sensor packaging module bracket (3) via a die-bonding adhesive or solder paste or eutectic solder.

6. A vital sign monitoring sensor module according to claim 2, characterized in that: The free-form surface silicone lens (21) formed by molding on the surface of the light-emitting diode tube core (2) has a light-emitting angle of less than or equal to 45°.

7. A vital sign monitoring sensor module according to claim 1, characterized in that: The wide-angle meta-lens (9) uses titanium dioxide, an artificial nanostructured material, wherein the diameter of the titanium dioxide ranges from 20 nm to 300 nm, and the height of the titanium dioxide microstructure ranges from 400 nm to 700 nm.

8. A vital sign monitoring sensor module according to claim 2, characterized in that: The distance D from the geometric center of the light emitting diode tube core (2) to the geometric center of the photodetector tube core (7) needs to be at least greater than 0.25 mm.

9. A vital sign monitoring sensor module according to claim 1, characterized in that: The wide-angle metalens (9), the phase distribution of the nanocolumn arrays at different positions on the metalens layer is: Wherein, k0 is the wave vector in free space, f is the corresponding focal length, r∈[0,2f] is the distance from any metastructure unit to the center of the metastructure lens; suppose the incident collimated light beam is located in the xz plane, and the angle with the normal axis of the lens is θ, where k0xsinθ is the gradient phase caused by oblique incidence, x is the horizontal coordinate of the metastructure lens, and y is the vertical coordinate of the metastructure lens.

10. A method for preparing a vital sign monitoring sensor module according to any one of claims 1 to 9, characterized in that: The vital sign monitoring sensor module is a free-form surface and wide-angle meta-lens vital sign monitoring module, which is a free-form surface light-emitting diode package transmitter part (1) after the standard wire bonding 4, 6 process is completed, and a wide-angle meta-lens (9) is installed on the wide-angle meta-lens photodetector receiver part (10). The specific steps are as follows: Step 1, selecting a light-emitting diode die (2), wherein the dominant wavelength of a green light chip is between 525nm and 535nm, the dominant wavelength of a red light chip is about 660nm, and the dominant wavelength of an infrared chip is between 935nm and 945nm; Step 2, selecting a photodetector die (7), wherein the photodetector is a PIN photodiode or a phototransistor; Step 3, cleaning the bracket: cleaning the vital sign sensor package module bracket (3) by plasma cleaning or ultrasonic cleaning; Step 4, bonding the crystal, using manual or automatic bonding machine to bond the crystal, using silver glue, solder paste, or eutectic soldering to connect all the tube cores to the vital sign sensor packaging module bracket (3) through bonding glue, solder paste, or eutectic solder; Step 5, wire bonding, using gold wire ball welding or aluminum wire ultrasonic welding, or copper wire or silver wire bonding, to connect the light-emitting diode die (2) and the vital sign sensor packaging module bracket (3) with a diode bonding wire (4), and to connect the photoelectric detector die (7) and the vital sign sensor packaging module bracket (3) with a detector bonding wire (6); Step 6, the free-form surface silicone lens (21) is formed into a free-form surface small-angle silicone lens by molding; Step 7, the wide-angle meta-lens (9) is prepared by nanoimprinting to prepare titanium dioxide nanorods with high aspect ratio on a silicon dioxide substrate; Step 8, pasting of the wide-angle meta-lens, using a high-precision die-bonding machine to pick up, align and place the wide-angle meta-lens (9).

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