On-chip integrated photoelectric pod system based on area array single photon avalanche diode

Abstract

The invention belongs to an on-chip integrated photoelectric pod system based on an area array single photon avalanche diode, and the system comprises an optical window which protects a photoelectric chip from being affected by rainwater, dust and the like, and has a specific spectrum anti-reflection effect; the mechanical shell provides physical support for the on-chip integrated photoelectric pod system; the photoelectric sensing chip is arranged in the mechanical shell and is used for realizing acquisition and fusion processing of visible light, infrared light or laser ranging information and realizing accurate servo control; the photoelectric sensing chip comprises a metasurface lens layer, a sensor layer, a data processing layer, a power management and interface layer, a heat dissipation layer and an MEMS galvanometer layer. Compared with the prior art, the photoelectric pod system has the advantages that the problems of large size, heavy weight and high cost of the photoelectric pod system caused by discrete devices at present are solved, the novel photoelectric pod system which is small in size, light in weight, low in cost and capable of being produced on a large scale is realized, and the shackles of the discrete devices on the size, the weight and the cost of the system are broken through.

Description

Technical Field

[0001] The invention relates to the technical field of optoelectronic pods, and in particular to an on-chip integrated optoelectronic pod system based on a planar array single photon avalanche diode. Background Art

[0002] With the rapid development of the low-altitude economy, unmanned equipment has gradually become active in various fields of the national economy. As the "eagle eyes" of drones, optoelectronic pods have always been one of the focuses of drone development. At present, optoelectronic pods are developing rapidly in the direction of low cost, small size, light weight and intelligence. However, existing optoelectronic pod systems are all composed of discrete optical sensors (visible light modules, infrared imaging modules, laser ranging modules, etc.), which makes the overall size of the optoelectronic pods relatively large, heavy, and costly, and cannot meet the consumer-grade, low-cost market demand. However, the detection sensitivity of the visible light module and the infrared thermal imaging module in the existing optoelectronic pod system is low, and weak target detection or hidden target detection cannot be achieved.

[0003] Compared with traditional visible light sensors (CMOS, CCD, etc.) and infrared thermal imaging sensors, single photon avalanche diodes (SPADs) have the ability to detect single photons, which can achieve ultra-long-distance target imaging and detection of weak or hidden targets. In addition, SPAD detectors have the ability of active and passive detection, and can achieve high-precision distance detection at the millimeter level. In the past decade, SPAD detectors have been rapidly developed through compatibility with CMOS technology, which has paved the way for planar array SPAD detectors and image processor architectures, and can increase the size of SPAD detector pixels in a miniaturized and scalable manner. SPAD detectors can be divided into Si SPADs and InGaAs / InP SPADs according to the material system, corresponding to the visible light band and the short-wave infrared band, respectively. In recent years, with the rapid development of heterogeneous hybrid on-chip integration technology, the heterogeneous hybrid technology of III-V InGaAs / InP materials and Si materials has gradually matured.

[0004] At present, the main hybrid heterogeneous integration technologies include: molecular covalent bonding technology, adhesive bonding technology, ion knife heterogeneous integration technology, three-dimensional heterogeneous hybrid integration technology and wafer hybrid integration technology.

[0005] According to previous research, traditional optoelectronic pod systems do not use the above-mentioned integration technology and SPAD technology. This patent proposes for the first time an on-chip integrated optoelectronic pod system based on a single-photon avalanche diode array, which overcomes the problems of large size, heavy weight and high cost of traditional optoelectronic pods, and can detect weak and hidden targets. It will greatly promote the integration and on-chip development of optoelectronic pods and help the rapid development of the low-altitude economy. Summary of the invention

[0006] The purpose of the present invention is to provide an on-chip integrated optoelectronic pod system based on a planar array single photon avalanche diode, characterized in that the on-chip integrated optoelectronic pod system based on a planar array SPAD can solve the current problems of large size, heavy mass and high cost of optoelectronic pod systems caused by discrete devices; to achieve the design of an optoelectronic pod system with small size, light weight, low cost and mass production, breaking through the shackles of discrete devices on system size, weight and cost.

[0007] The technical solution to achieve the purpose of the present invention is: an on-chip integrated optoelectronic pod system based on a planar array single photon avalanche diode, the on-chip integrated optoelectronic pod system mainly includes:

[0008] Optical window: protects the optoelectronic chip from rain, dust, etc., and has a specific spectral anti-reflection effect;

[0009] Mechanical shell: provides physical support for the on-chip integrated optoelectronic pod system, facilitating connection and installation with unmanned equipment;

[0010] Photoelectric sensor chip: installed in the mechanical housing to collect and integrate visible light, infrared light or laser ranging information, and achieve precise servo control; photoelectric sensor chips include: area array Si SPAD and area array InGaAs / InPSPAD.

[0011] Compared with the prior art, the present invention has the following significant advantages:

[0012] 1. Realize on-chip integration of visible light and infrared through hybrid heterogeneous integration technology and wafer to wafer packaging technology;

[0013] 2. Two area array SPADs made of different materials are used to replace traditional CMOS and infrared cameras to achieve single-photon level sensitivity detection; at the same time, the SPAD detector directly converts visible light signals and infrared light signals into digital electrical signals, avoiding the analog-to-digital conversion of traditional sensors and realizing a fully digital on-chip processing system.

[0014] 3. Hybrid heterogeneous integration technology and wafer to wafer packaging technology directly connect the sensing layer and the data processing layer, achieving high-bandwidth on-chip data transmission and breaking through the bottleneck of limited data processing rate of traditional optoelectronic pod systems.

[0015] 4. For the first time, MEMS galvanometer technology is introduced into the optoelectronic pod to achieve on-chip high-precision, large-angle horizontal and pitch axis control. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is composed of an on-chip integrated optoelectronic pod system structure;

[0017] Figure 2 It is a 2D photoelectric sensor chip;

[0018] Figure 3 It is a 3D photoelectric sensor chip. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0020] The present invention proposes an on-chip integrated optoelectronic pod system based on area array SPAD. Based on hybrid heterogeneous integration technology, wafer to wafer wafer packaging technology and SPAD technology, the design of the on-chip integrated optoelectronic pod system is realized, and the core of the system is the optoelectronic sensor chip 2.

[0021] The on-chip integrated optoelectronic pod system mainly includes: an optical window 1, an optoelectronic sensor chip 2, and a mechanical housing 3, such as Figure 1 Its specific functions are as follows:

[0022] Optical window 1: protects the optoelectronic chip from rain, dust, etc., and has a specific spectral anti-reflection effect;

[0023] Photoelectric sensor chip 2: realizes the collection and fusion processing of visible light, infrared light or laser ranging information, and realizes precise servo control.

[0024] Mechanical shell 3: provides physical support for the on-chip integrated optoelectronic pod system, facilitating connection and installation with unmanned equipment.

[0025] The core of the on-chip integrated optoelectronic pod system is the optoelectronic sensor chip. In the optoelectronic sensor chip, the area array SiSPAD and the area array InGaAs / InP SPAD respectively replace the visible light sensor and infrared thermal imaging sensor in the traditional optoelectronic pod. The growth of Si SPAD and InGaAs / InP SPAD on the same wafer is achieved through hybrid heterogeneous integration technology, realizing on-chip integrated detection and imaging of visible light and infrared light. Compared with common visible light sensors and infrared thermal imaging sensors, the area array SPAD has single-photon sensitivity, which can realize weak target detection and hidden target detection. The main structure of the optoelectronic sensor chip is realized through three-dimensional hybrid heterogeneous integration technology and wafer to wafer wafer packaging technology.

[0026] Embodiment 1:

[0027] An on-chip integrated optoelectronic pod system based on area array SPAD, such as Figure 1 As shown, it includes an optical window 1, a 2D photoelectric sensor chip 4 and a mechanical housing 3.

[0028] Optical window: used to protect optoelectronic chips from rain, dust, etc., and has a specific spectral anti-reflection effect.

[0029] Mechanical shell: used to provide physical support for the on-chip integrated optoelectronic pod system to facilitate connection and installation with the drone.

[0030] The 2D photoelectric sensor chip 4 is the core of the on-chip integrated photoelectric pod system. Its function is to realize the collection and fusion processing of visible light, infrared light or laser ranging information, and to achieve high-precision servo control. The 2D photoelectric sensor chip 4 consists of six parts: metasurface microlens layer, sensor layer, data processing layer, power management and interface layer, heat dissipation layer and MEMS galvanometer layer. Figure 2 As shown,

[0031] Metasurface microlens 4-1: The main function is to achieve filtering and focusing. Through micro-nanostructure design and light field control, the surface of the metasurface microlens is divided into two regions, one for visible light and the other for short-wave infrared 1μm-2μm. The function of the metasurface microlens is to focus visible light and infrared light on the focal planes of the array Si SPAD and array InGaAs / InPSPAD respectively, and filter stray light in other bands. The field of view of visible light and infrared light can be designed according to the actual application.

[0032] Sensor layer 4-2: The main function is to realize the collection of visible light and infrared image information. The area array Si SPAD detector realizes the collection of visible light image information, and the area array InGaAs / InP detector realizes the collection of infrared light image information. The area array Si SPAD and the area array InGaAs / InP SPAD are integrated on the same wafer through hybrid heterogeneous integration technology to realize on-chip integrated detection and imaging of visible light and infrared light. Compared with common visible light sensors and infrared thermal imaging sensors, the area array SPAD has single-photon sensitivity and can realize weak target detection and hidden target detection. Data processing layer: The main function is to realize the fusion processing of visible light and infrared image information and MEMS galvanometer control.

[0033] Data processing layer 4-3: It is mainly composed of FPGA chips and SOC (system on chip) chips. The FPGA chip is mainly responsible for high-speed parallel preprocessing of visible light and infrared image information. Specifically: control the SPAD chips of two material systems (Si and InGaAs / InP), including timing, power-on, data acquisition, etc., and pre-process the collected image signals, including noise reduction, filtering and image enhancement; the SOC chip is mainly used for image target recognition, locking, tracking and high-precision control of MEMS galvanometers. Specifically: SOC uses AI algorithms to identify, lock and track the preprocessed image signals, and encodes the generated video stream; while locking and tracking the target, SOC controls the MEMS galvanometer to achieve angular rotation in the pitch, horizontal or roll directions.

[0034] It should be noted that the SOC chip in the data processing layer includes CPU, storage chip, etc.

[0035] Power management and interface layer 4-4: including power chip and interface conversion chip, where the power chip is responsible for the management of the power system of the entire 2D photoelectric sensor chip 4, and the interface conversion chip provides interface conversion function for data transmission. The video stream data transmitted by the dedicated interface is transmitted to the ground display and control platform or other designated display and control platform through the image transmission platform to assist the UAV to make reasonable decisions.

[0036] Heat dissipation layer 4-5: mainly provides heat dissipation for the data processing layer, power management and interface layer, ensures the normal operation of the 2D photoelectric sensor chip 4, and avoids downtime caused by excessive temperature.

[0037] MEMS galvanometer layer 4-6: realizes the pitch and horizontal scanning functions of the 2D photoelectric sensor chip 4, and adds a micro-electromechanical system layer (MEMS, Micro-Electro-Mechanical System) to the main body of the 2D photoelectric sensor chip 4. The MEMS-based two-dimensional scanning mirror has the characteristics of small size, low driving power consumption, high scanning frequency, and long life. It can achieve large-angle horizontal and pitch control and provide fast field of view switching for the on-chip integrated photoelectric pod system. The MEMS galvanometer is mainly composed of a horizontal axis, a pitch axis, and a micro-electromechanical galvanometer.

[0038] Each layer is bonded to another layer through wafer-to-wafer bonding technology (such as Cu-Cu hybrid bonding, micro-bumps), and each small chip or chiplet in a wafer is connected by metal wires in the interposer in the wafer, or the wafer is interconnected through TSV technology. This wafer-to-wafer bonding method is a 3D packaging method that can maximize the performance of 2D optoelectronic sensor chips 4, achieve high-bandwidth on-chip data transmission, and break through the bottleneck of limited data processing rate of traditional optoelectronic pod systems.

[0039] The FPGA in this embodiment can be replaced by other signal control and preprocessing modules, or directly replaced by SOC. The SOC chip can be composed of many sub-modules, including ARM, CPU, GPU, power management chip, etc. Similarly, the functions of SOC can be realized by a combination of ARM, CUP, GPU, etc.

[0040] It should be noted that this photoelectric sensor chip is not only suitable for photoelectric pods, but also for other photoelectric sensing systems.

[0041] Embodiment 2:

[0042] An on-chip integrated optoelectronic pod system based on area array SPAD is different from the first embodiment in that a light source layer is added to the optoelectronic sensor chip, and a 3D data processing algorithm is added to the data processing layer. More importantly, the SPAD chip in the sensing layer has 3D detection capabilities. Figure 3 As shown in Figure 2, the on-chip integrated optoelectronic pod system based on the 3D sensor chip can simultaneously obtain the 2D and 3D information of the target.

[0043] The 3D optoelectronic sensor chip 5 is composed of a metasurface microlens layer, a light source layer, a sensor layer, a data processing layer, a power management and interface layer, a heat dissipation layer, and a MEMS galvanometer layer.

[0044] Light source layer 5-1: A single point or array laser emits a laser beam, and beam shaping is achieved through a metasurface microlens. The metasurface microlens focuses the laser light diffusely reflected from the target on the focal plane of the array Si SPAD or InGaAs / InP SPAD to obtain the target's 3D distance information.

[0045] Sensing layer 5 - 2 : Compared with the SPAD chip in the 2D photoelectric sensor chip 4 , the SPAD chip in the 3D photoelectric sensor chip 5 adds a peripheral TDC circuit to achieve high-precision time recording.

[0046] Data processing layer 5-3: Add point cloud data processing algorithm and image and point cloud matching fusion algorithm to achieve high-precision matching fusion of high-precision two-dimensional image information and 3D point cloud information.

[0047] The on-chip integrated optoelectronic pod system based on the area array SPAD of the present invention can solve the problems of large size, heavy mass and high cost of the current optoelectronic pod system caused by discrete devices, and realize a new optoelectronic pod system with small size, light weight, low cost and large-scale production, breaking through the shackles of discrete devices on system volume, weight and cost. The area array SPAD detector has the advantages of small size, high sensitivity and wide coverage band. Through the two optical windows 1 of visible light and infrared light, it can realize detection from visible to infrared band, so it can replace the traditional visible light module and infrared thermal imaging module. In addition, the area array SPAD detector can integrate the peripheral TDC timing circuit to achieve high-precision time measurement.

[0048] It should be noted that this photoelectric sensor chip is not only suitable for photoelectric pods, but also for other photoelectric sensing systems.

Claims

1. An on-chip integrated optoelectronic pod system based on a single-photon avalanche diode array, characterized in that: The on-chip integrated optoelectronic pod system mainly includes: Optical window: used to protect optoelectronic chips from rain and dust, and has a specific spectral anti-reflection effect; Mechanical shell: used to provide physical support for the on-chip integrated optoelectronic pod system, facilitating connection and installation with unmanned equipment; Photoelectric sensor chip: It is installed in the mechanical housing and is used to collect and fuse visible light, infrared light or laser ranging information, and to achieve precise servo control; the photoelectric sensor chip includes area array Si SPAD and area array InGaAs / InPSPAD.

2. The on-chip integrated optoelectronic pod system based on area array single photon avalanche diode according to claim 1 is characterized in that: Area array Si SPAD and area array InGaAs / InP SPAD in photoelectric sensor chips; through hybrid heterogeneous integration technology, Si SPAD and InGaAs / InP SPAD are grown on the same wafer, realizing on-chip integrated detection and imaging of visible light and infrared light.

3. The on-chip integrated optoelectronic pod system based on area array single photon avalanche diode according to claim 2 is characterized in that: The photoelectric sensor chip is a 2D photoelectric sensor chip, including: The metasurface microlens layer mainly realizes filtering and focusing functions; The sensor layer mainly collects visible light and infrared image information, identifies, locks, and tracks image targets, and controls the MEMS galvanometer. Data processing layer, used for parallel preprocessing of visible light and infrared image information; The power management and interface layer includes the power chip and the interface conversion chip. The power chip is responsible for the management of the power system of the entire 2D photoelectric sensor chip, and the interface conversion chip provides interface conversion function for data transmission. The heat dissipation layer mainly provides heat dissipation for the data processing layer, power management and interface layer to ensure the normal operation of the 2D photoelectric sensor chip; The MEMS galvanometer layer realizes the pitch and horizontal scanning functions of the 2D photoelectric sensor chip.

4. The on-chip integrated optoelectronic pod system based on area array single photon avalanche diode according to claim 3 is characterized in that: The layers of the 2D optoelectronic sensor chip are bonded to each other using wafer-to-wafer bonding technology.

5. The on-chip integrated optoelectronic pod system based on area array single photon avalanche diode according to claim 3 is characterized in that: At the sensor layer, the area array Si SPAD detector realizes the collection of visible light image information, and the area array InGaAs / InP detector realizes the collection of infrared light image information; the area array Si SPAD and the area array InGaAs / InP SPAD are integrated on the same wafer through hybrid heterogeneous integration technology to realize on-chip integrated detection and imaging of visible light and infrared light.

6. The on-chip integrated optoelectronic pod system based on area array single photon avalanche diode according to claim 3 is characterized in that: The data processing layer includes FPGA chip and SOC chip; the FPGA chip is used for parallel preprocessing of visible light and infrared image information; the SOC chip is used for image target recognition, locking, tracking and MEMS galvanometer control.

7. The on-chip integrated optoelectronic pod system based on area array single photon avalanche diode according to claim 3 is characterized in that: A light source layer is added to the 2D photoelectric sensor chip. The light source layer: a single-point or planar array VCSEL laser emits a laser beam of equal wavelength, and beam shaping is achieved through a metasurface microlens; the metasurface microlens converges the laser diffusely reflected by the target on the focal plane of the planar array Si SPAD to achieve 3D distance information acquisition of the target.

8. The on-chip integrated optoelectronic pod system based on area array single photon avalanche diode according to claim 7 is characterized in that: A 3D data processing algorithm is added to the data processing layer; a point cloud data processing algorithm and an image and point cloud matching and fusion algorithm are added to realize the matching and fusion of two-dimensional image information and 3D point cloud information.

9. The on-chip integrated optoelectronic pod system based on area array single photon avalanche diode according to claim 8 is characterized in that: Sensing layer: The SPAD chip is equipped with a peripheral TDC circuit.

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