3D structured light module, assembly method and three-dimensional imaging device

Abstract

The application discloses a 3D structured light module, an assembling method and a three-dimensional imaging device. The 3D structured light module comprises a bracket provided with a first inner cavity and a second inner cavity; a projector module is arranged in the first inner cavity; a first laser light source is located on a focal plane of a collimating phase plane of an optical element; a second laser light source is fixed on a conductive pad and located on a virtual focal plane of the collimating phase plane of the optical element; the first laser light source and the second laser light source are connected with a control circuit; the control circuit controls the first laser light source and the second laser light source to emit light alternately, so that the optical element outputs structured light and uniform infrared light alternately; and an infrared camera module is arranged in the second inner cavity, and the infrared camera module is used for outputting a uniform infrared image and an infrared light spot image with coding features alternately. The 3D structured light module provided by the application can reduce the volume of the structured light module, so that the miniaturization design of the imaging device is realized.

Description

Technical Field

[0001] This invention relates to the field of facial recognition technology, and in particular to a 3D structured light module, assembly method, and three-dimensional imaging device. Background Technology

[0002] Facial recognition technology is a key research project in the field of biometric identification. Compared with other identity verification technologies, facial recognition technology has advantages such as being contactless, fast, and capable of recognizing multiple people simultaneously, and has been applied in various fields such as smart door locks, mobile payments, and turnstiles. From the perspective of facial expression models, it is divided into 2D facial recognition and 3D facial recognition. Due to the lack of depth data in 2D recognition, the security factor is not high enough, which limits its application scenarios. 3D facial recognition uses 3D camera stereo imaging, which can accurately identify attacks such as photos, videos, and masks, and has a wider range of application scenarios. Among them, 3D structured light has become the mainstream solution used in existing 3D facial recognition technology due to its high precision and simple algorithm.

[0003] Existing 3D structured light modules for facial recognition include a structured light projector, a flood illuminator, and an infrared camera. Typically, the structured light projector, flood illuminator, and infrared camera are fixed as three independent modules on a structural support and connected to the main board via three board-to-board connectors. This structure is complex to assemble, has high material and assembly costs, and the module baseline distance is generally greater than 25mm, resulting in a large module size, which is not conducive to the miniaturization design of the imaging device. Summary of the Invention

[0004] The main objective of this invention is to provide a 3D structured light module that addresses the technical problems of complex assembly, large baseline distance, and large module size in current 3D structured light modules for face recognition, which hinders the miniaturization design of imaging devices.

[0005] To achieve the above objectives, the present invention proposes a 3D structured light module, comprising:

[0006] The stent has a first inner cavity and a second inner cavity;

[0007] A projector module, located in the first inner cavity, includes a first laser source, a second laser source, a conductive elevation plate, and optical elements. The first laser source is located on the focal plane of the collimated phase plane of the optical element, and the second laser source is fixed to the conductive elevation plate and located on the virtual focal plane of the collimated phase plane of the optical element. A control circuit connects the first and second laser sources, controlling them to emit light alternately, causing the optical element to output structured light and uniform infrared light alternately.

[0008] An infrared camera module is disposed in the second inner cavity. The infrared camera module is used to output uniform infrared images and infrared spot images with coded features at intervals.

[0009] Optionally, the baseline distance B between the optical center of the projector module and the optical center of the infrared camera module is ≤10mm.

[0010] Optionally, the 3D structured light module further includes a circuit board module and a connection module. The first laser source and the second laser source are electrically connected to the circuit board module, and the bracket is fixedly connected to the circuit board module. The connection module is used to connect to an external motherboard.

[0011] Optionally, the infrared camera module includes an infrared imaging chip, electronic components, an infrared lens, and an infrared filter, wherein the infrared imaging chip and the electronic components are respectively connected to the circuit board module, the infrared lens is connected to the bracket, and the infrared imaging chip is located on the imaging focal plane of the infrared lens.

[0012] Optionally, the infrared lens is a conventional lens, the infrared lens is threadedly connected to the bracket, and the infrared filter is fixedly disposed at one end of the infrared lens near the circuit board module; or,

[0013] The lens uses a traditional lens, the infrared lens is bonded to the bracket, and the infrared filter is fixed to the end of the infrared lens near the circuit board module; or...

[0014] The lens is a traditional lens, the infrared lens is bonded to the bracket, the second inner cavity has a second stepped surface, and the infrared filter is disposed on the second stepped surface.

[0015] Optionally, the infrared lens is an infrared metasurface lens, the second inner cavity is provided with a third step surface and a fourth step surface, the infrared lens is disposed on the third step surface, and the infrared filter is disposed on the fourth step surface.

[0016] Optionally, an isolation column is provided between the first inner cavity and the second inner cavity, and the first inner cavity is also provided with a first stepped surface, on which the optical element is disposed.

[0017] Optionally, the distance D1 between the entrance pupil position of the infrared lens and the infrared imaging chip, and the distance D2 between the microstructure surface of the optical element and the laser light source, satisfy |D1-D2|≤1mm; and / or,

[0018] The distance D3 between the top surface of the infrared camera module and the circuit board, and the distance D4 between the top surface of the projector module and the circuit board, satisfy |D3-D4|≤0.5mm.

[0019] The present invention also proposes a three-dimensional imaging device, including a 3D structured light module and a motherboard, wherein the 3D structured light module is as described above, the 3D structured light module is disposed on the motherboard, the motherboard is further provided with a processing chip and a transmission interface, the processing chip is communicatively connected to the 3D structured light module and the transmission interface respectively, and the transmission interface is used to connect to a host computer.

[0020] This invention also proposes an assembly method for a 3D structured light module, applicable to the 3D structured light module described above, the assembly method comprising:

[0021] Laser source one, laser source two, conductive pad, infrared imaging chip, electronic components, and connection module are attached to the circuit board module. When fixing laser source one, laser source two, and conductive pad to the circuit board module, they are first pre-baked to bond them to the circuit board module with conductive adhesive. The three components need to meet a certain pushing force. Then, the three components and the circuit board module are baked together for a long time to ensure that the conductive adhesive achieves complete adhesion.

[0022] This invention employs a bracket with a first inner cavity and a second inner cavity. The projector module is located in the first inner cavity, and the infrared camera module is located in the second inner cavity. The small baseline distance reduces the size of the structured light module. Integrating the projector and infrared camera into a single module further reduces the overall size of the structured light module. The projector module includes a first laser source, a second laser source, a conductive pad, and optical elements. The first laser source is located on the focal plane of the collimated phase plane of the optical element, while the second laser source is fixed to the conductive pad and located on the virtual focal plane of the collimated phase plane of the optical element. A control circuit connects the first and second laser sources, controlling them to emit light at intervals. This allows the laser to output structured light and uniform infrared light at intervals through the optical elements. Compared to existing technologies, this eliminates the need for a collimating lens, saving material costs and reducing assembly and production difficulty and costs. This integration of the structured light projector and floodlight illuminator into a single projector further reduces the size of the structured light module, achieving a miniaturized design for the imaging device. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of a typical existing 3D structured light module;

[0025] Figure 2 This is a schematic diagram of the structure of a 3D structured light module provided by the present invention;

[0026] Figure 3 for Figure 2 Schematic diagram of the mid-support structure;

[0027] Figure 4 This is a schematic diagram of another 3D structured light module provided by the present invention;

[0028] Figure 5 for Figure 4 Schematic diagram of the mid-support structure;

[0029] Figure 6 This is a schematic diagram of another 3D structured light module provided by the present invention;

[0030] Figure 7 for Figure 6 Schematic diagram of the mid-support structure;

[0031] Figure 8 This is a schematic diagram of the structure of the three-dimensional imaging device provided by the present invention.

[0032] Explanation of icon numbers:

[0033] 101 Infrared camera 2014、5014、7014 Optical components 102 floodlights 2021、5021、7021 Infrared imaging chip 103 Structured light projector 2022、5022、7022 electronic devices 104 Structural support 2023、5023、7023 Infrared filter 105 Motherboard 1 2024、5024、7024 Infrared lens 1011、1021、1031 Board-to-board connectors 2051、5051、7051 First step surface 201、401、501、701 Projector Module 5052 Second step surface 202、402、502、702 Infrared camera module 2052 screw thread 203、503、703 Circuit board module 2053 isolation column 204、504、704 Connection module 7052 Third step surface 205、505、705 support 7053 Fourth step surface 206、506、706 AA glue 403 motherboard 2011、5011、7011 Laser source 1 404 Processing chip 2012、5012、7012 Conductive pad 405 Resistor and capacitor components 2013、5013、7013 Laser source two 406 Transmission interface

[0034] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0036] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0037] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0038] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0039] This invention proposes a 3D structured light module.

[0040] Existing 3D structured light modules for face recognition include a structured light projector, a flood illuminator, and an infrared camera. On one hand, the infrared camera receives the uniform infrared light projected by the flood illuminator, obtaining a uniform infrared image. This uniform infrared image can perform face detection, face bounding, face feature comparison, and face recognition in different scenarios. On the other hand, after a face is detected, the structured light projector is activated, and the infrared camera receives the structured light projected by the projector, obtaining a structured light spot map with structural features. This structured light spot map with structural features is used by algorithms to calculate a depth map. The depth map adds depth information of the target object, effectively countering planar attack methods.

[0041] Thus, in the field of facial recognition, existing typical 3D structured light modules, such as Figure 1As shown, the structured light projector 103, floodlight illuminator 102, and infrared camera 101 are typically fixed as three independent modules on the structural support 104 and connected to the main board 105 via board-to-board connectors 1011, 1021, and 1031 (three board-to-board connectors are required). This structure is complex to assemble, has high material and assembly costs, and the module baseline distance is generally greater than 25mm (the distance between the optical center of the infrared camera 101 and the optical center of the structured light projector 103 is called the baseline distance), resulting in a large module size, which is not conducive to the miniaturization design of the imaging device.

[0042] To address the aforementioned technical problems, the present invention employs a bracket with a first inner cavity and a second inner cavity. The projector module is located in the first inner cavity, and the infrared camera module is located in the second inner cavity. The small baseline distance reduces the size of the structured light module. Integrating the projector and infrared camera into a single module further reduces the overall size of the structured light module. The projector module includes a first laser source, a second laser source, a conductive pad, and optical elements. The first laser source is located on the focal plane of the collimated phase plane of the optical element, while the second laser source is fixed to the conductive pad and located on the virtual focal plane of the collimated phase plane of the optical element. A control circuit connects the first and second laser sources, controlling them to emit light at intervals. This allows the laser to output structured light and uniform infrared light at intervals through the optical elements. Compared to existing technologies, this eliminates the need for a collimating lens, saving material costs and reducing assembly and production difficulty and costs. This integration of the structured light projector and floodlight illuminator into a single projector further reduces the size of the structured light module, achieving a miniaturized design for the imaging device.

[0043] The above technical solution will be described in detail below with reference to the accompanying drawings.

[0044] Example 1:

[0045] In this embodiment, reference Figure 2 The image shows a 3D structured light module provided in this embodiment, where (a) is a front view of the 3D structured light module and (b) is a cross-sectional view of the 3D structured light module. The 3D structured light module includes:

[0046] The support 205 has a first inner cavity and a second inner cavity;

[0047] Projector module 201, located in the first inner cavity, includes a laser source one 2011, a laser source two 2013, a conductive elevation plate 2012, and an optical element 2014. Laser source one 2011 is located on the focal plane of the collimated phase plane of optical element 2014. Laser source two 2013 is fixed to the conductive elevation plate 2012 and located on the virtual focal plane of the collimated phase plane of optical element 2014. A control circuit connects laser source one 2011 and laser source two 2013, controlling the laser source one 2011 and laser source two 2013 to emit light alternately, causing the laser to output structured light and uniform infrared light alternately through optical element 2014.

[0048] Infrared camera module 202 is located in the second inner cavity. Infrared camera module 202 is used to output uniform infrared images and infrared spot images with coded features at intervals.

[0049] In the specific implementation process, the projector module 201 projects uniform infrared light (flood light) and structured light with coded features at intervals to the object under test. The reflected light from the object under test is imaged on the infrared camera module 202. The infrared camera module 202 outputs uniform infrared images and infrared spot images with coded features at intervals. The uniform infrared images are used for face detection and face bounding, while the infrared spot images with structured features are used to calculate a depth map through an algorithm for face liveness detection.

[0050] The projector module 201 includes a laser source one 2011, a conductive pad 2012, a laser source two 2013, and an optical element 2014. The laser source one 2011 can be an array of VCSELs (vertical cavity surface laser emitters), HCCSELs (horizontal cavity surface laser emitters), etc., composed of multiple pseudo-randomly distributed light-emitting holes. The laser source two 2013 can be an array of VCSELs or LEDs. When the laser source two 2013 is an array of VCSELs, the light spot arrangement on it can be composed of multiple pseudo-randomly distributed light-emitting holes or multiple regularly arranged light-emitting holes. Here, it is preferred to be composed of multiple regularly arranged light-emitting holes. The optical element 2014 integrates collimation and diffraction functions. It can be a collimation and diffraction optical element 2014 or a metasurface structure element. It integrates the collimation function of a traditional collimating lens and the replication diffraction function of a diffraction optical element 2014 into a single optical element 2014, eliminating the need for a collimating lens and saving material costs, assembly and production difficulty, and costs. The projector module 201 and the infrared camera module 202 share a bracket 205, which integrates the projector and the infrared camera into a single module, further reducing the size of the structured light module.

[0051] The 3D structured light module in this embodiment also includes a circuit board module 203 and a connection module 204. Laser source one 2011 and laser source two 2013 are electrically connected to the circuit board module 203, and the bracket 205 is fixedly connected to the circuit board module 203. The connection module 204 is used to connect to an external motherboard.

[0052] In the specific implementation process, laser source one 2011 is located on the focal plane of the collimated phase plane of optical element 2014. Laser source two 2013 is elevated by conductive pad 2012 and located on the virtual focal plane of the collimated phase plane of optical element 2014. The lower surface of laser source one 2011, i.e., the cathode, is electrically connected to circuit board module 203 via conductive adhesive. The conductive adhesive is an adhesive with both bonding and conductivity properties, generally doped with a high concentration of metal particles, such as conductive silver paste, copper powder conductive paste, nickel-carbon conductive paste, silver-copper conductive paste, etc. The upper surface anode pad of laser source one 2011 is electrically connected to circuit board module 203 via gold wire soldering. The gold wire is a metal conductor, which can be conductive copper wire, aluminum wire, gold wire, etc. The lower surface of laser source two 2013, i.e., the cathode, is electrically connected to conductive pad 2012 via conductive adhesive. The upper surface anode pad of laser source two 2013 is electrically connected to circuit board module 203 via gold wire. On 203, the conductive pad 2012 can be a copper block plated with nickel-palladium-gold, or a ceramic substrate with electrically conductive upper and lower surfaces. The lower surface of the conductive pad 2012 is electrically connected to the circuit board module 203 via conductive adhesive, and the upper surface of the conductive pad 2012 is electrically connected to the laser source 2013 via conductive adhesive. When the laser source 2011, which contains N light-emitting points, passes through the optical element 2014, it is collimated and replicated into a structured light spot with M*N points, where M is the replication order of the optical element 2014. When the light emitted by the laser source 2013 passes through the optical element 2014, since the laser source 2013 is located on the virtual focal plane of the optical element 2014, the replicated light spots are superimposed on each other, making the output light uniform infrared light. The laser source 2011 and the laser source 2013 can be controlled by an external control circuit to emit light alternately, so that the projector module 201 outputs structured light and uniform infrared light alternately. The structured light projector and floodlight illuminator are integrated into a single projector, further reducing the size of the structured light module.

[0053] The circuit board module 203 can be a PCB (Printed Circuit Board), a rigid-flex board, an FPC (Flexible Printed Circuit) reinforced with steel sheets, or a ceramic substrate with good heat dissipation. The connection module 204 can be a board-to-board connector or a gold finger. Through the connection module 204, the 3D structured light module can be electrically connected to the motherboard.

[0054] In this embodiment, the first inner cavity is further provided with a first stepped surface 2051, and the optical element 2014 is disposed on the first stepped surface 2051. (See reference) Figure 2 and 3 The optical element 2014 is fixed to the first stepped surface 2051 of the bracket 205 using low-flow adhesive. The bracket 205 is fixed to the circuit board module 203 using AA adhesive 206. AA adhesive 206 is an abbreviation for adhesive used in the active focusing technology of camera AA process. It is generally a UV adhesive and uses a dual curing method of UV + heat curing to achieve the expected adhesive strength. This is prior art and will not be described in detail in this embodiment.

[0055] Furthermore, the infrared camera module 202 includes an infrared imaging chip 2021, electronic components 2022, an infrared lens 2024, and an infrared filter 2023. The infrared imaging chip 2021 and electronic components 2022 are respectively connected to the circuit board module 203, the infrared lens 2024 is connected to the bracket 205, and the infrared imaging chip 2021 is located on the imaging focal plane of the infrared lens 2024.

[0056] In this embodiment, the infrared imaging chip 2021 is electrically connected to the circuit board module 203 via solder or red glue and gold wire. The electronic component 2022 can be a capacitor, diode, resistor, or other electronic component 2022, electrically connected to the circuit board module 203 via solder (for simplicity, only one electronic component 2022 is shown here; the actual number is set according to the imaging requirements of the infrared chip). The infrared lens 2024 consists of one or more lenses and a lens barrel. The infrared filter 2023 is directly integrated into the lens barrel, and the infrared filter 2023 is a narrow-band infrared filter. The function of the narrow-band infrared filter is to cut off the light beam in the light reflected from the object under test that is inconsistent with the wavelength range emitted by the projector. Figure 2 and Figure 3 The infrared lens 2024 uses a traditional lens, and the infrared filter 2023 is fixedly installed at one end of the infrared lens 2024 near the circuit board module 203. The infrared lens 2024 is threadedly connected to the bracket 205. Specifically, the second inner cavity is provided with threads 2052. The infrared lens 2024 is locked in the bracket 205 through the threads 2052. By rotating the infrared lens 2024, the distance between the infrared lens 2024 and the infrared imaging chip 2021 can be adjusted, thereby achieving clear imaging at different object distances. The infrared imaging chip 2021 is located on the imaging focal plane of the infrared lens 2024. The bracket 205 is connected to the circuit board module 203 by AA glue.

[0057] An isolation pillar 2053 is provided between the first inner cavity and the second inner cavity to isolate the laser light source 1 2011 and the laser light source 2013 from the infrared imaging chip 2021, so as to prevent the light emitted by the laser light source 1 2011 and the laser light source 2013 from being reflected by the first inner cavity and the second inner cavity of the bracket 205 and directly forming an image on the infrared imaging chip 2021, thus creating background noise.

[0058] Optionally, the baseline distance B between the optical center of the projector module 201 and the optical center of the infrared camera module 202 is ≤10mm. With a short baseline, the overall size of the structured light module can be made very small.

[0059] The distance D1 between the entrance pupil position of the infrared lens 2024 and the infrared imaging chip, and the distance D2 between the microstructure surface of the optical element 2014 and the laser source, satisfy |D1-D2|≤1mm; and / or,

[0060] The distance D3 between the top surface of the infrared camera module 202 and the circuit board module 203, and the distance D4 between the top surface of the projector module 201 and the circuit board module 203, satisfy |D3-D4|≤0.5mm.

[0061] against Figure 2 Because the baseline is smaller than that of traditional structured light modules, and structured light is based on the principle of triangulation to calculate depth distance, the smaller the baseline distance, the lower the accuracy of long-distance measurement. In order to ensure the measurement accuracy when the baseline distance is small, the distance D1 between the entrance pupil position of the infrared lens 2024 (the entrance pupil of the lens is the effective aperture that restricts the incident light beam on the object surface, and is the image formed by the aperture stop of the lens on the optical system in front; if the aperture stop is the top surface of the first lens, then the top surface of the first lens is the entrance pupil position) and the infrared imaging chip 2021, and the distance D2 between the microstructure surface of the optical element 2014 and the laser source 2011, must meet certain conditions, namely, |D1-D2|≤1mm. Under the condition of short baseline, certain conditions must be met to ensure measurement accuracy.

[0062] In addition, to facilitate the subsequent assembly and cooperation of the 3D module with the terminal (mobile terminal, cabinet or robot, etc.) and to facilitate the opening design of the terminal structure, the distance D3 between the top surface of the infrared camera module 202 and the circuit board module 203 and the distance D4 between the top surface of the projector module 201 and the circuit board module 203 must also meet certain conditions, namely |D3-D4|≤0.5mm, in order to optimize the opening of the terminal structure.

[0063] The assembly process of the 3D structured light module provided in this embodiment can be briefly described as follows: That is, the present invention also proposes a method for assembling a 3D structured light module, the assembly method including:

[0064] Laser source 1 2011, laser source 2 2013, conductive pad 2012, infrared imaging chip 2121, electronic component 2022, and connection module 204 are attached to circuit board module 203. Specifically, when fixing laser source 1 2011, laser source 2 2013, and conductive pad 2012 to circuit board module 203, they are first rapidly pre-baked to bond them to the circuit board module with conductive adhesive, ensuring sufficient force. Then, they are baked together with the circuit board module for an extended period to achieve complete adhesion of the conductive adhesive. The specific steps are as follows:

[0065] Assembly Step 1: Attach the laser light source 1 2011, conductive pad 2012, laser light source 2 2013, electronic components 2022, infrared imaging chip 2021, and connection module 204 to the circuit board module 203.

[0066] Specifically, for step one: If the infrared imaging chip 2021 is a CSP chip, then 1) the electronic components 2022, the infrared imaging chip 2021, and the connection module 204 are first soldered onto the circuit board using SMT process with solder paste; 2) the lower surface of the laser source 2011 is fixed to the circuit board module 203 using conductive adhesive through the DB (Die bond) process in COB process, and the laser source 2011 is initially fixed to the circuit board module 203 through rapid pre-baking, meeting certain pushing force requirements (the force required to push the laser source 2011), generally baking time ≤ 10 minutes; 3) the lower surface of the conductive pad 2012 is fixed to the circuit board module 203 using conductive adhesive through the DB (Die bond) process in COB process, so that the conductive pad 2012 is initially fixed to the circuit board module 203, meeting certain pushing force requirements (the force required to push the conductive pad 2012), generally baking time ≤ 10 minutes; 4) the lower surface of the conductive pad 2012 is fixed to the circuit board module 203 using conductive adhesive through the DB (Die bond) process in COB process ...5) the lower surface of the conductive pad 2012 is fixed to the circuit board module 203 through the DB (Die bond) process in COB process, meeting certain pushing force requirements (the force required to push the conductive pad 2012), generally baking time ≤ 10 minutes; 6) the lower surface of the conductive pad 2012 is fixed to the circuit board module 203 through the DB The process involves: 1) fixing the lower surface of laser source 2013 to the conductive pad 2012 using conductive adhesive, thus initially fixing laser source 2013 to the conductive pad 2012 and meeting certain pushing force requirements (the force required to push laser source 2013). The baking time is generally ≤10 minutes. 2) Baking the circuit board module 203 with the corresponding components (laser source 1, laser source 2, and conductive pad) for 2-3 hours to ensure the conductive adhesive achieves full adhesion. 3) Using the WB (Wireless Bonding) process in COB... The bonding process electrically connects the anode pads on the upper surfaces of laser light source 1 2011 and laser light source 2 2013 to the circuit board module 203. In the traditional COB process, the bonding process involves attaching the components to the circuit board with conductive silver adhesive and then baking for 2-3 hours to fully fix them. However, the conductive adhesive serves to conduct electricity, adhere, and conduct heat, and its high metal content results in a long curing time. Therefore, fixing three components—laser light source 1 2011, conductive pad 2012, and laser light source 2 2013—requires 6-9 hours to complete the bonding process. This invention, after each component is fixed to the circuit with conductive adhesive, first quickly bakes for initial fixation, and then bakes all three components for 2-3 hours, significantly shortening the bonding process time and greatly improving production efficiency. After applying the conductive adhesive, the circuit board module needs to be repositioned to attach other components or transferred to other machines for other operations. Since the conductive adhesive is liquid, without initial fixation, the position of the attached components can easily change when the circuit board is moved, leading to defects.

[0067] If the infrared imaging chip 2021 is a COB chip, the steps are slightly different: 1) First, solder the electronic components 2022 and the connection module 204 to the circuit board module 203 using SMT process with solder paste; 2) Fix the infrared imaging chip 2021 to the circuit board module 203 with red glue using the DB (Diebond) process in COB process, and quickly bake it to allow the glue to exert its full adhesive force. Red glue is different from conductive glue, and the curing time is shorter, generally within 6 minutes; 3) Fix the laser light source 1 2011, conductive pad 2012, and laser light source 2 2013 to the circuit board module 203 respectively using the DB process in COB process, and connect the anode pads of laser light source 1 2011 and laser light source 2 2013 to the circuit board module 203 with gold wire using the WB process (the process is the same as above, and will not be repeated here).

[0068] Assembly Step 2: Align the geometric center of the optical element 2014 with the window geometric center of the first step surface 2051, and attach the optical element 2014 to the bracket 205 using low-flow adhesive.

[0069] Assembly Step 3: Using the AA process, align the optical center of optical component 2014 with the optical center of laser source 2011, as follows: Figure 2 The aligned optical axis shown is the O-axis marked with a dashed line, placing the laser source 2011 on the focal plane of the collimated phase plane of the optical element 2014. A slight offset in the XY direction can be made according to the actual situation (allowing 2011 and 2013 to be symmetrically distributed about the optical axis O in the XY plane). The bracket 205 is fixed to the circuit board module 203 using AA adhesive layer 206. The AA process utilizes Adaptive Alignment technology. By processing images of the laser source 2011 relative to the optical element 2014 at different positions captured by a high-definition camera, different field-of-view sharpness and resolution values ​​are obtained. Then, an automatic feedback control 6-DOF moving platform aligns the optical element 2014 and the laser source 2011, applies AA adhesive, and performs UV curing. Active Alignment, compared to traditional Passive Alignment such as the COB process, differs in that it does not use external position or size for alignment but rather uses images captured by a high-definition camera, resulting in higher alignment accuracy.

[0070] Assembly Step 4: Attach the infrared lens 2024 to the bracket 205, adjust the distance between the infrared lens 2024 and the infrared imaging chip 2021 by the threads so that the infrared imaging chip 2021 is located on the focal plane of the infrared lens 2024, and fix the infrared lens 2024 to the bracket 205 by applying glue.

[0071] The above four steps complete the assembly and production of the entire 3D structured light module.

[0072] The assembly process of existing 3D structured light modules can be summarized as follows:

[0073] 1. Assembly of the structured light projector module

[0074] Assembly Step 1: In the DB process of COB, the lower surface of the laser source is attached to the circuit board 1 with conductive adhesive and baked for 2-3 hours. Then, in the WB process of COB, the anode pads on the upper surface of the laser source are electrically connected to the circuit board 1 with gold wire.

[0075] Assembly Step 2: Attach the diffractive optical element to the collimating lens barrel, i.e., structural support one;

[0076] Assembly Step 3: Using the AA process, align the optical center of the diffractive optical element with the optical center of the laser source, and fix the structural support to the circuit board using AA glue; thus completing the assembly of the structured light projector module.

[0077] Part Two: Assembly of the Infrared Camera Module

[0078] Assembly Step 1: If the infrared receiver chip is a CSP chip, then attach the infrared receiver chip and electronic components to circuit board 2 using SMT technology. If the infrared receiver chip is a COB chip, first attach the electronic components to circuit board 2 using SMT technology, then attach the lower surface of the laser source to circuit board 2 using conductive adhesive through the DB process of COB technology, bake for 2-3 hours, and then use the WB process of COB technology to electrically connect the anode pads on the upper surface of the laser source to circuit board 2 using gold wire.

[0079] Assembly Step Two: Attach the filter to Structural Support Two;

[0080] Assembly Step 3: Align the center of the window on the structural bracket with the optical center of the infrared receiver chip, and fix the structural bracket to the circuit board 2 with black glue;

[0081] Assembly Step 4: Using the AA process, align the optical center of the infrared lens with the optical center of the infrared receiving chip, and fix the infrared lens to the structural bracket with AA glue; thus completing the assembly of the infrared camera module.

[0082] Three: Flood Light Source Module

[0083] Assembly Step 1: Attach the laser light source or infrared filler lamp to the circuit board using COB or SMT processes;

[0084] Assembly Step 2: Align the optical center of the diffuser with the window center of structural bracket 3, and use low-bend adhesive to fix the diffuser to structural bracket 3;

[0085] Assembly Step 3: Align the center of the window on the structural bracket with the light-emitting center of the laser source or infrared filler lamp, and fix the structural bracket three to the circuit board three with black glue; complete the packaging of the floodlight module;

[0086] 4. Fix the structured light projector module, infrared camera module, and flood light source module onto the structural bracket 4 respectively (this also requires alignment and glue application in three steps).

[0087] In comparison, the 3D structured light module provided in this embodiment has many advantages:

[0088] 1) Projector module: The structured light projector module and the floodlight module are merged into one projection module, reducing the number of floodlight illuminators (specifically reducing the use of the diffuser and structural support), and the collimating lens and diffractive optical elements are integrated into one optical element, reducing the number of collimating lenses.

[0089] 2) The infrared camera module integrates the infrared filter into the lens barrel of the infrared lens, reducing the need for a separate structural support for attaching and fixing the filter as a single component.

[0090] 3) The projector module and the infrared camera module share a single structural support, which reduces the use of multiple structural supports, greatly reduces material costs, and significantly reduces assembly steps, saving assembly time and assembly costs.

[0091] 4) The projector module and the infrared camera module share a single circuit board, which reduces the use of multiple circuit boards and connection modules, greatly reducing material costs and assembly steps and costs.

[0092] 5) The module baseline is less than 10mm, and the entire 3D structured light module is small in size, which can meet the application needs of thinner or smaller mobile electronic devices.

[0093] Example 2

[0094] In this embodiment, see Figure 4 As shown, this is another 3D structured light module provided in this embodiment, where (a) is a front view of the 3D structured light module and (b) is a cross-sectional view of the 3D structured light module. The 3D structured light module proposed in this embodiment includes a projector module, an infrared camera module, a circuit board module, and a connection module as described in Embodiment 1. The projector module and the infrared camera module share a bracket. This is to ensure compatibility with Embodiment 1. Figure 2 and Figure 3 For distinction, please refer to Figure 4 and Figure 5 As shown, the labels for each structure in this embodiment are as follows:

[0095] Projector module 501, infrared camera module 502, circuit board module 503, connection module 504, bracket 505, AA glue 506, laser light source one 5011, conductive shim 5012, laser light source two 5013, optical element 5014, infrared imaging chip 5021, electronic device 5022, infrared filter 5023, infrared lens 5024, first step surface 5051, second step surface 5052.

[0096] Optionally, the infrared lens 5024 uses a conventional lens, is bonded to the bracket 505, and the infrared filter 5023 is fixed to one end of the infrared lens 5024 near the circuit board module 503; or, the infrared lens 5024 uses a conventional lens, is bonded to the bracket 505, and the second inner cavity has a second stepped surface 5052, on which the infrared filter 5023 is disposed. In this embodiment, the infrared lens 5024 uses a conventional lens, which differs from Embodiment 1 in that: 1) the infrared lens 5024 used in this embodiment is an integrated lens, while Figure 2 The infrared lens 2024 is a threaded lens; 2) the infrared filter 5023 can be integrated into the barrel of the infrared lens 5024, or placed on the second stepped surface 5052 of the bracket 505. Figure 4 (b) shows that the infrared camera module 502 uses an integrated lens and the infrared lens 5024 is attached by the AA process, which results in higher assembly precision.

[0097] The assembly steps for the 3D structured light module proposed in this embodiment are as follows:

[0098] Assembly Step 1: Attach the laser light source 5011, conductive pad 5012, laser light source 5013, infrared imaging chip 5021, electronic components 5022, and connection module 504 to the circuit board 503; (The steps are the same as described in Example 1, and will not be repeated here).

[0099] Assembly Step 2: Align the geometric center of the optical element 5014 with the window geometric center of the first step surface 5051, and attach the optical element 5014 to the bracket 505 using low-flow adhesive.

[0100] Assembly Step 3: Using the AA process, align the optical center of optical element 5014 with the optical center of laser source 5011, such as... Figure 4(b) The aligned optical axis is the O axis marked by the dashed line, so that the laser source 1 5011 is located on the focal plane of the collimation phase plane of the optical element 5014. A small offset in the XY direction can be made according to the actual situation, so that the laser source 1 5011 and the laser source 2 5013 are symmetrically distributed about the optical axis O in the XY plane. The bracket 505 is fixed to the circuit board module 503 by AA glue 506.

[0101] Assembly Step 4: After aligning the optical center of the infrared lens 5024 with the optical center of the infrared imaging chip 5021 using the AA process, use AA glue 506 to fix the infrared lens 5024 onto the circuit board module 503; thus completing the assembly of the 3D structured light module.

[0102] This embodiment and Figure 2 Differences: Figure 2 The infrared lens 2024 and the bracket 205 are connected by threads. The bracket is attached to the circuit board during assembly step three according to the alignment requirements of the projector module, not according to the alignment requirements during infrared camera assembly. The infrared lens can only be adjusted in the height direction to change its distance from the chip. To achieve better imaging results from the infrared camera, the X and Y dimensions of the bracket attached to the infrared camera module must meet certain tolerance requirements. This places high demands on the precision of the bracket 205, the flatness of the circuit board, the consistency of the assembly equipment, and the overall assembly precision. However, in embodiment two... Figure 4 In the process of attaching the projector module 501 to the circuit board module 503, the relative positions of the infrared lens 5024 and the infrared imaging chip 5021 can be adjusted again through the AA process. The position of the infrared lens 5024 can be adjusted in six degrees of freedom so that the infrared imaging chip 5021 is at the optimal imaging plane of the infrared lens 5024, thereby achieving the best imaging effect. A suitable solution can be selected according to the actual situation.

[0103] Example 3

[0104] In this embodiment, see Figure 6 The image shows another 3D structured light module provided by the present invention, wherein (a) is a front view of the 3D structured light module and (b) is a cross-sectional view of the 3D structured light module. The 3D structured light module proposed in this embodiment includes a projector module, an infrared camera module, a circuit board module, and a connection module as described in Embodiment 1. The projector module and the infrared camera module share a bracket. This is to ensure compatibility with Embodiment 1. Figure 2 and Figure 3 For distinction, please refer to Figure 6 and Figure 7 As shown, the labels for each structure in this embodiment are as follows:

[0105] Projector module 701, infrared camera module 702, circuit board module 703, connection module 704, bracket 705, AA glue 706, laser light source one 7011, conductive shim 7012, laser light source two 7013, optical element 7014, infrared imaging chip 7021, electronic device 7022, infrared filter 7023, infrared lens 7024, first step surface 7051, third step surface 7052, fourth step surface 7053.

[0106] In this embodiment, the infrared lens 7024 is an infrared metasurface lens. The second inner cavity has a third stepped surface 7052 and a fourth stepped surface 7053. The infrared lens 7024 is disposed on the third stepped surface 7052, and the infrared filter 7023 is disposed on the fourth stepped surface 7053. Specifically, it is similar to that in Embodiment 1. Figure 2 The differences are: 1) The infrared lens 7024 here is not composed of traditional lenses, but is an infrared metasurface lens; 2) The infrared filter 7023 is attached to the fourth step surface 7053 of the second inner cavity of the bracket 705. The infrared lens uses an infrared metasurface lens, which has lower material costs and a smaller module size.

[0107] Metasurfaces, based on the generalized Snell's law, introduce subwavelength-scale unit structures on the surface to generate abrupt phase changes, allowing for the manipulation of the phase, amplitude, and polarization of the light field within a two-dimensional plane. Optical devices designed based on metasurfaces are characterized by miniaturization, lightweight design, and integration. Metasurfaces are considered a revolutionary technology in the field of optics, with the potential to completely overturn the cumbersome lens groups in traditional optical systems and become the next generation of mainstream optical components. Metasurface lenses are generally made by etching or depositing multiple subwavelength-scale units arranged in a certain pattern on a high-transmittance substrate material. Commonly used substrate materials include quartz, SiO2, polymer materials, and PC, while commonly used microstructure materials include metals such as copper, aluminum, gold, and titanium, or dielectric materials such as silicon, silicon nitride, TiO2, and aluminum arsenide.

[0108] The assembly steps of the 3D structured light module in this embodiment are as follows:

[0109] Assembly Step 1: Attach the laser light source 7011, conductive pad 7012, laser light source 7013, infrared imaging chip 7021, electronic components 7022, and connection module 704 to the circuit board module 703; (The steps are the same as described in Embodiment 1, and will not be repeated here).

[0110] Assembly Step 2: According to the alignment requirements of geometric dimensions, attach the optical element 7014, infrared filter 7023 and infrared lens 7024 to the bracket 705 in sequence.

[0111] Assembly Step 3: Using the AA process, align the optical center of the infrared lens 7024 with the optical center of the infrared imaging chip 7021, such as... Figure 6 (b) The aligned optical axis is the O axis marked by the dashed line, and the relative position of the optical center of the optical element 7014 and the infrared imaging chip 7021 is within a certain tolerance range. The bracket 705 is fixed to the circuit board module 703 using AA glue 706.

[0112] This structured light module has a higher integration level, can be made smaller, and has a simpler assembly process. Since the optical center of the infrared camera is used as the reference AA, the relative position of the laser source 7011 and the optical element 7014 is determined by the processing accuracy of the structural bracket, the flatness of the circuit board, and the AA attachment tolerance. This places high demands on the processing accuracy of the structural bracket, the flatness of the circuit board, and the assembly accuracy.

[0113] against Figure 6 Alternatively, the functions of the infrared filter 7023 and the infrared lens 7024 can be integrated onto a single metasurface lens, which further reduces material costs and assembly steps.

[0114] Example 4

[0115] refer to Figure 8 As shown, this embodiment proposes a three-dimensional imaging device, including a 3D structured light module and a motherboard. The 3D structured light module is the same as described in Embodiments 1, 2, and 3, and is mounted on the motherboard 403. The motherboard 403 also includes a processing chip 404 and a transmission interface 406. The processing chip 404 is communicatively connected to both the 3D structured light module and the transmission interface 406, and the transmission interface 406 is used to connect to a host computer. Additionally, the motherboard also includes resistors and capacitors 405.

[0116] The 3D structured light module includes a projector module and an infrared camera module as described in Embodiments 1, 2, and 3. The projector module and the infrared camera module share a bracket, in order to be compatible with Embodiment 1. Figure 2 and Figure 3 For distinction, please refer to Figure 8 As shown, the labels of the various structures in this embodiment are as follows: projector module 401, infrared camera module 402.

[0117] Specifically, in this embodiment, when the user sends an imaging command to the 3D imaging device, the processing chip 404 receives the imaging command and sends it to the projector module 401 of the 3D structured light module. After receiving the imaging command, the projector module 401 projects structured light and uniform infrared light onto the imaging target. At the same time, the processing chip 404 also sends an imaging command to the infrared camera module 402 of the 3D structured light module. The infrared camera module 402 receives the imaging command and acquires the imaging information of the imaging target, and sends the imaging information to the processing chip 404. The processing chip 404 receives the imaging information and processes it to obtain the distance measurement data and other data required by the user, and transmits it to the host computer through the transmission interface 406. The processing chip 404 may integrate modules such as ISP and MCU, or the ISP and MCU may be mounted as separate modules on the motherboard 403. The transmission interface 406 may be an interface such as USB, UART, or LVDS, which transmits the image data processed by the algorithm to the host computer. The projector module 401 and the infrared camera module 402 are directly connected to the motherboard 403, eliminating the need for electrical connection to the motherboard via the connection modules described in Embodiments 1, 2, and 3. This allows for higher integration of the entire 3D structured light module, saving the cost of a circuit board and a connection module, resulting in lower material costs and further reducing assembly steps and costs. Thus, the projector, infrared camera, and motherboard share a common substrate, leading to even higher integration.

[0118] In this embodiment, the 3D imaging device is assembled by attaching laser light source one, laser light source two, conductive pad, infrared imaging chip, electronic components, processing chip, and transmission interface to the motherboard. Please refer to Embodiments 1, 2, and 3 for details on these components. In this embodiment, when fixing laser light source one, laser light source two, and the conductive pad to the motherboard, they are first rapidly pre-baked to bond the components to the motherboard with conductive adhesive. The components must meet a certain pushing force. Then, the components and the motherboard are baked together for an extended period to ensure complete adhesion of the conductive adhesive. The assembly process for other structures is described in Embodiments 1, 2, and 3 above.

[0119] Therefore, in this invention, the structured light projection function, floodlight illumination function, and infrared camera function are integrated into a single module. It is connected to the motherboard through a board-to-board connector, or the module is directly attached to the motherboard through a common substrate. This greatly reduces the number of optical materials used and the module assembly steps. Moreover, the module baseline distance is less than 10mm, and the entire 3D structured light module is small in size. It can meet the application requirements of thinner or smaller mobile electronic devices while achieving ultra-low cost.

[0120] The above description is merely an optional embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A 3D structured light module, characterized in that, include: The stent has a first inner cavity and a second inner cavity; A projector module, located in the first inner cavity, includes a first laser source, a second laser source, a conductive elevation plate, and optical elements. The first laser source is located on the focal plane of the collimated phase plane of the optical element, and the second laser source is fixed to the conductive elevation plate and located on the virtual focal plane of the collimated phase plane of the optical element. A control circuit connects the first and second laser sources, controlling them to emit light alternately, causing the optical element to output structured light and uniform infrared light alternately. An infrared camera module is disposed in the second inner cavity, and the infrared camera module is used to output uniform infrared images and infrared spot images with coded features at intervals; The baseline distance B between the optical center of the projector module and the optical center of the infrared camera module is ≤10mm; The distance D1 between the entrance pupil position of the infrared lens and the infrared imaging chip, and the distance D2 between the microstructure surface of the optical element and the laser light source, satisfy |D1-D2|≤1mm.

2. The 3D structured light module as described in claim 1, characterized in that, The 3D structured light module also includes a circuit board module and a connection module. The first laser source and the second laser source are electrically connected to the circuit board module, and the bracket is fixedly connected to the circuit board module. The connection module is used to connect to an external motherboard.

3. The 3D structured light module as described in claim 2, characterized in that, The infrared camera module includes an infrared imaging chip, electronic components, an infrared lens, and an infrared filter. The infrared imaging chip and the electronic components are respectively connected to the circuit board module, the infrared lens is connected to the bracket, and the infrared imaging chip is located on the imaging focal plane of the infrared lens.

4. The 3D structured light module as described in claim 3, characterized in that, The infrared lens uses a traditional lens and is threadedly connected to the bracket. The infrared filter is fixedly mounted on one end of the infrared lens near the circuit board module; or... The infrared lens uses a traditional lens and is bonded to the bracket. The infrared filter is fixed to the end of the infrared lens near the circuit board module; or... The infrared lens is a traditional lens and is bonded to the bracket. The second inner cavity has a second stepped surface, and the infrared filter is disposed on the second stepped surface.

5. The 3D structured light module as described in claim 3, characterized in that, The infrared lens is an infrared metasurface lens. The second inner cavity has a third step surface and a fourth step surface. The infrared lens is disposed on the third step surface, and the infrared filter is disposed on the fourth step surface.

6. The 3D structured light module as described in claim 1, characterized in that, An isolation column is provided between the first inner cavity and the second inner cavity. The first inner cavity is also provided with a first stepped surface, and the optical element is disposed on the first stepped surface.

7. The 3D structured light module as described in claim 3, characterized in that, The distance D3 between the top surface of the infrared camera module and the circuit board module, and the distance D4 between the top surface of the projector module and the circuit board module, satisfy |D3-D4|≤0.5mm.

8. A three-dimensional imaging device, characterized in that, The device includes a 3D structured light module and a motherboard. The 3D structured light module is the same as described in claim 1. The 3D structured light module is mounted on the motherboard. The motherboard also has a processing chip and a transmission interface. The processing chip is communicatively connected to the 3D structured light module and the transmission interface, respectively. The transmission interface is used to connect to a host computer.

9. A method for assembling a 3D structured light module, characterized in that, Applied to the 3D structured light module as described in any one of claims 1-7, the assembly method includes: Laser source one, laser source two, conductive pad, infrared imaging chip, electronic components, and connection module are attached to the circuit board module. When fixing laser source one, laser source two, and conductive pad to the circuit board module, they are first quickly pre-baked to bond them to the circuit board module with conductive adhesive. The three components need to meet a certain pushing force. Then, the three components and the circuit board module are baked together for a long time to ensure that the conductive adhesive achieves complete adhesion.

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