report produced/author: Huachuang Securities, Geng Chen, Yueyang
The following is an excerpt from the original report
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1. Lidar : Product maturity continues to improve, and the vehicle field has good prospects
LiDAR (Laser Detecting and Ranging) is a measurement tool that irradiates a target with a pulse laser and uses a sensor to measure the return time of the reflected pulse to measure the target distance. Its working principle is to emit a detection signal ( laser beam ) to the target, and then compare the received signal reflected from the target (target echo) with the transmitted signal. After appropriate processing, the relevant information of the target can be obtained, thereby detecting, tracking and identifying the surrounding environment. It consists of laser transmitter, optical receiver, turntable and information processing system. Its core advantage is to use the high-frequency characteristics of laser to measure a large number of high-speed position and speed information to form an accurate and clear 3D construction of objects.
Lidar was introduced into the automotive field at the beginning of the 21st century. With the increase in the penetration rate of ADAS, has ushered in rapid development. Lidar was first used in the field of map surveying, and the high accuracy requirements made the cost of lidar remain high. Velodyne applied lidar to the DARPA Driverless Vehicle Challenge, bringing lidar into the field of autonomous driving for the first time. Subsequently, with the continued development of downstream applications such as ADAS, the number of companies in the lidar field continued to increase. As research and development continued, the performance of lidar products steadily improved, the cost dropped significantly, and the industry also ushered in considerable development.
lidar products can be evaluated and compared in terms of explicit parameters, measured performance and implicit indicators. Explicit parameters mainly refer to the information listed in in the product parameter table, mainly including distance measurement capability, point frequency, angular resolution, field of view, accuracy, power consumption and integration level, etc. Actual measured performance mainly refers to the product performance measured during the actual use of lidar, which determines the effective sensing distance of driverless cars and service robots to the surrounding environment. Compared with explicit parameters, users will pay more attention to measured performance. However, lidar, as an emerging product that has only gained high attention in the market in recent years, has limited public test data for reference. Hidden indicators include the reliability, safety, service life, cost control, mass production, etc. of lidar products. These indicators are more difficult to quantify and there is a lack of public information.
(1) Lidar technology routes are diverse and are still in the parallel stage of multiple technology routes
Lidar technology routes have four main dimensions: ranging principle, light source, detector, and beam manipulation . Lidar mainly includes four major systems: laser emission, scanning system, laser reception and information processing. The four systems complement each other. Based on the different characteristics of these four systems, the lidar technology route can be explained from four different dimensions. The light source and detector are the transmitting end and receiving end of the lidar, the beam steering is the scanning method of the lidar, and the ranging provides distance information for information processing. Lidar can be classified according to four main dimensions, and each different classification method can be further subdivided into different technical routes. There are large differences between different routes.
According to the ranging method classification, lidar can be divided into 4 types . There are four main types of lidar based on ranging principles: Time of Flight (ToF), Frequency Modulated Continuous Wave (FMCW), triangulation ranging and phase method. The two main measurement methods are ToF and FMCW. The ToF measurement principle is to measure the distance by recording the time between the emission of a short pulse and the reception of the reflected light, and measure the position of the object through the angle of the reflected light during the measurement process.The measurement principle of FMCW is to linearly modulate the light frequency of the emitted laser, so that the echo signal and the reference light are coherently beat to obtain the frequency difference to indirectly obtain the flight time and infer the target distance. The advantage is that it has strong anti-interference and can directly measure the speed.
ToF ranging method is currently the mainstream, and FMCW has good prospects. Among the lidar ranging methods, ToF and FMCW can achieve longer range measurement (100~250m) under outdoor sunlight, and are the preferred solutions for vehicle-mounted lidar . ToF is currently the mainstream solution in the vehicle-mounted medium and long-range lidar market. It has a very high laser emission frequency and has the advantage of high-precision detection. However, the maximum laser power of ToF lidar is limited, and there is a bottleneck in the detection range. It will be interfered by sunlight during the day and generate noise during the signal reception process. In addition to its high cost, FMCW lidar has the advantages of directly measuring speed information, anti-interference, and high long-range. In the future, as the FMCW lidar machine and the upstream industry chain mature, its proportion is expected to increase and become the main ranging method coexisting with ToF.
The detector in the lidar, namely the photodetector , can be divided into four categories: PIN PD, APD, SPAD and SiPM. APD is the current mainstream .
PIN PD (PIN photodiode ) is suitable for FMCW ranging laser radar and has low cost;
APD (Avalanche Photo Diode) is an avalanche photodiode. The more mature APD is widely used in ToF It is currently the most widely used photoelectric detection device in the LiDAR class;
SPAD (single photon avalanche diode) has long-distance detection capabilities at low laser power, but its disadvantage is that its overly sensitive receiving performance will cause problems such as large channel crosstalk and parasitic pulses. In addition, its circuit design and other process problems also It brings higher manufacturing costs;
SiPM ( silicon photomultiplier tube ) is an array form of multiple SPADs. It can obtain a higher detectable range through multiple SPADs and use it with the array light source, making it easier to integrate CMOS technology.
EEL has a complicated production process, and VCSEL is expected to usher in the rapid development of in the future. In terms of laser light sources, they can be divided into two categories from the emission dimension: edge emission (EEL) and vertical cavity surface emission (VCSEL). According to the prospectus of Hesai Technology, EEL has the advantage of high luminous power density as a detection light source. However, because its light-emitting surface is located on the side of the semiconductor wafer, complex process steps of cutting, flipping, coating, and re-cutting are required during use. Moreover, each laser greatly relies on the manual assembly and adjustment technology of production line workers, resulting in high production costs and difficulty in ensuring consistency. Because the light-emitting surface of VCSEL is parallel to the semiconductor wafer, the laser array formed by it is easy to bond with the planar circuit chip, eliminating the need for separate assembly and adjustment of each laser. It is also easy to integrate with the silicon material micro-lens processed on the surface, which can effectively improve the beam quality. In recent years, many VCSEL laser companies at home and abroad have developed multi-junction VCSEL lasers, which has effectively improved the optical power density of VCSEL and allowed VCSEL to be used in the field of long-range lidar. From the perspective of production cost and product performance reliability, VCSEL is expected to gradually replace EEL in the future.
lasers are classified according to laser wavelength. 905nm and 1550nm wavelength lasers complement each other and coexist . The most critical indicator of laser is wavelength. The wavelength is mainly divided into two mainstream emission bands, namely within 1000nm and between 1000 and 2000nm. The typical value within 1000nm is 905nm, and the typical value between 1000nm and 2000nm is 1550nm.
905nm is a near-infrared laser that is easily absorbed by the human retina and causes retinal damage. Therefore, the 905nm solution can only operate at low power and the safe detection distance does not exceed 200m, but its cost is relatively low.
1550nm is far away from the visible light wavelength of the human eye. Most of the light will be absorbed by the transparent part of the eyeball before reaching the retina. The safe power limit is 40 times that of 905nm. The safe detection distance can reach 250 meters or even more than 300 meters. However, it requires the use of fiber laser , which is more expensive than 905nm.
Generally speaking, 905nm and 1550nm lasers have their own advantages and disadvantages at the current point of time. The two bands are complementary and coexisting for vehicle-mounted sensors.
mechanical lidar still occupies a major position in the industry, and semi-solid/solid-state lidar has good prospects.. According to the classification of scanning methods, lidar is mainly divided into mechanical lidar, semi-solid lidar and solid-state lidar. In the long term, solid-state lidar has great potential in terms of cost and stability because it has no movable parts, and is the optimal technical solution. Among the three current technical routes, the mechanical type is the most commonly used and has been widely used in fields such as Robotaxi. The hybrid lidar is a compromise between the mechanical type and the pure solid-state type (the mechanical type only scans a range within a certain angle in front; the pure solid-state type still has some smaller moving parts). It is the mainstream product for mass production and installation of passenger cars at this stage.
mechanical radar development is relatively mature, but it is difficult to achieve car-grade mass production of due to cost and complicated components. The technical solution for mechanical lidar is mainly a high-line-count mechanical solution. Mechanical lidar, which uses a motor to drive the overall rotation of the optical-mechanical structure, is a classic technical architecture of lidar. The innovations in its technological development are reflected in the increase in the number of system channels, the expansion of ranging range, the improvement of spatial angular resolution, and the improvement of system integration and reliability. Compared with semi-solid and solid-state lidar, the advantage of mechanical rotating lidar is that it can scan the surrounding environment with a 360° horizontal field of view and has stronger ranging capabilities within the field of view. However, the rotating parts are large in size and weight, and the high-frequency rotation and complex mechanical structure make the internal rotating parts easily damaged and have a relatively short service life, making it difficult to meet the stringent requirements of vehicle regulations. In addition, it relies on increasing the number of transceiver modules to achieve a high wiring harness, which makes the cost higher and limits its large-scale use.
semi-solid solutions mainly include micro-mirror (MEMS) solutions and rotating mirror solutions . The characteristic of the semi-solid solution is that the transceiver unit is decoupled from the scanning component . The transceiver unit (such as laser, detector) no longer performs mechanical movement. The activity of the scanning component realizes the detection of part of the field of view (such as forward). The volume is more compact than the mechanical rotating radar. The
rotating mirror solution is relatively mature, and its reliability has been verified by vehicle regulations . The rotating mirror solution fixes the transceiver module and uses a 360° high-speed rotating polygonal prismatic reflector to reflect the beam and complete the full field of view scanning within the lidar field of view. The advantage of the rotating mirror is that the prism, motor and transmitter have better heat resistance and durability, so it is easier to pass the vehicle regulations. Currently, Valeo's Scala1 using the rotating mirror solution has passed the vehicle regulations certification. Rotating mirrors are regarded as the only way to advance mechanically to pure solid state. It is the mainstream in the short term, and semi-solid state and pure solid state will be parallel for a long time in the future.
MEMS radar is limited by the deflection range of the galvanometer and the small field of view, and its strong mass production brings low-cost advantages . MEMS galvanometer is a silicon-based semiconductor component, which is a solid-state electronic component. It integrates a very compact micro-galvanometer on a silicon-based chip. Its core structure is a very small cantilever beam . The deflection of the lens is achieved through the vibration of the cantilever beam. MEMS micro-vibration mirrors get rid of mechanical motion devices such as motors, and millimeter-sized micro-vibration mirrors greatly reduce the size of lidar. Due to its high level of integration, it is expected to have greater advantages in cost and reliability after the process matures. The technological innovation of MEMS solutions is reflected in the development of technical solutions with larger aperture, higher frequency, and better reliability than galvanometers, so that they are suitable for laser radar. However, the deflection angle of MEMS currently on the market is only 10-30 degrees. In order to solve the problem of small field of view, multiple first-generation modules are often required to be spliced together.
The solid-state solution does not contain mechanical parts and is easier to pass vehicle regulations, but the technology maturity is relatively low and still requires further development of .The characteristic of the solid-state solution is that it no longer contains any mechanical moving parts and is suitable for detection of partial field of view (such as forward). It specifically includes optical phased array (OPA) solutions, Flash solutions, electronic scanning solutions, etc. Because it does not contain mechanical scanning devices, its internal structure is the most compact compared to other architectures, giving it an advantage in terms of volume.
OPA is still in its infancy, and its manufacturing difficulty and cost are higher than . Optical phased array technology (OPA) adjusts the phase relationship of each phase-controlled unit by applying voltage, and uses the principle of coherence to deflect the emitted beam, thereby completing the system's scanning measurement of a certain range of space. In OPA systems, optical phase modulators are used to control the light beam passing through the lens. OPA has the advantages of high precision, fast scanning, small size, high integration and high degree of mass production standardization, and has strong technical advantages. However, because the OPA industry chain is still in its infancy and the manufacturing process is complex, there are still problems with mass production. In addition, due to its complex structure, there are also problems such as high control complexity and high power consumption.
Flash lidar can quickly record scenes, but its short detection range limits its application to . Flash lidar is classified as a solid-state lidar because it does not have a scanning system or mechanical moving parts. Flash-type lidar can quickly record the entire scene by emitting large-coverage array lasers in all directions in a short period of time, avoiding various troubles caused by the movement of targets or lidar during the scanning process. It operates more like a camera, with laser beams that diffuse directly in all directions, illuminating an entire scene with just one quick flash. The system then uses an array of micro-sensors to collect laser beams reflected from different directions. The disadvantage is that once the propagation distance exceeds tens of meters, the returned photons are greatly reduced, making reliable detection impossible. At the same time, it also increases the height requirements for the receiving end and power, and increases the cost.
(2) The division of labor in the lidar industry chain is clear, and the rapid development of automotive downstream applications continues to increase
lidar integration connects the upstream and downstream of the industry chain, and has strong industrial added value . Lidar mainly includes four major systems: laser emission, scanning system, laser reception and information processing. The different electronic components and optical systems required by the four systems together form the upstream of the industrial chain. Specifically, the upstream industrial chain of the lidar industry mainly includes lasers, detectors, scanning mirrors, FPGA chips , analog chips, and optical component manufacturers and processors. It is the cornerstone of the laser industry and has high entry barriers; the midstream of the industry chain utilizes upstream laser chips and optoelectronic devices , modules, optical components, etc. are used as pump sources for the manufacturing and sales of various types of lidar; the downstream of the industrial chain mainly includes the application fields of various types of lidar, including driverless cars, advanced assisted driving, service robots , surveying and mapping, high-precision maps, etc. LiDAR industry chain companies have a clear division of labor. Midstream integrated companies play a connecting role in the industry chain and have a strong industrial position.
The upstream of the industry chain is dominated by foreign manufacturers, and the gap between domestic and foreign manufacturers in the downstream continues to narrow.. The core components in the upstream of lidar are lasers and detectors. Foreign suppliers have been working in the laser and detector industry for a long time and have competitive advantages in products. Domestic suppliers have developed rapidly in recent years, and domestic lasers and detectors that have passed vehicle regulations have been put on the market. The downstream industry chain of lidar is mainly divided into industries such as driverless driving, advanced assisted driving, service robots and Internet of Vehicles according to application fields.Foreign autonomous driving technology research started earlier and still has a certain leading edge compared to domestic ones. However, domestic autonomous driving technology research is developing rapidly, with continuous application pilots and projects being implemented, and the gap with foreign companies is constantly narrowing. Thanks to the high maturity of the domestic express delivery and instant distribution industries, the domestic technology development level in the field of service robots is comparable to that of foreign countries. In terms of the richness of robot types and the diversity of landing scenarios, domestic companies have more advantages; the Internet of Vehicles industry is developing faster than abroad under the strong promotion of national policies such as "new infrastructure".
The cost of the laser transceiver module accounts for a large proportion of the cost of lidar. The overall cost is expected to further decline with the advancement of mass production in the future. Breaking down the cost of each component of the mechanical lidar, according to data from Automobile Heart, the cost of Velodyne's mechanical lidar VLP-16 after dismantling the cost of the laser, detector, optical components, circuit board, motor housing and structural parts is 40%, 35%, 10%, 10%, and 5% respectively. Taking Valeo's Scala rotating mirror lidar as an example, the total cost of its laser transceiver-related module laser board, mechanical mirror and mechanical laser components accounts for up to 46%. Whether it is mechanical or semi-solid-state lidar, the cost of laser transceiver-related modules is relatively high. This is partly because the current overall shipment volume of lidar is small and the fixed cost is relatively high. As the mass production of lidar advances, the overall cost of the product is expected to decline further.
At present, the surveying and mapping field dominates downstream applications, and the automotive driving field is expected to become the main in the future. Lidar has a wide range of downstream applications, mainly involving unmanned driving, high-end assisted driving, service robots, smart cities, surveying and mapping and other industries. According to data from Yole Intelligence's "2022 Lidar Application Report in Automotive and Industrial Sectors", terrain mapping will still be the largest application field among lidar applications in 2021, accounting for 60% of the market share ; followed by the industrial field, accounting for 27%; driverless taxis , ADAS ( Advanced Driver Assistance System ), wind energy and national defense and other fields occupy the remaining 13%. However, in recent years, with the policy support for intelligent driving in various countries around the world and the rapid development of the automotive lidar industry, the penetration rate of lidar in autonomous driving and advanced assisted driving has been growing rapidly. FrostSullivan predicts that by 2025, advanced assisted driving and driverless driving will become the main downstream applications, accounting for 34.64% and 26.30% of the lidar market respectively. The automotive lidar field will contribute 61% to the growth of the overall market.
2. Intelligent and electrified two-wheel drive, the lidar market is expected to usher in broad growth space
(1) Intelligentization and electrification are advancing steadily, and the ADAS market is ushering in rapid growth
ADAS (Advanced Driving Assistance System) can use various sensors installed on the car ( millimeter wave radar , lidar, single and binocular cameras, and satellite navigation) to collect data, and combine it with map data to perform system calculations to predict possible dangers for the driver and ensure driving safety. ADAS technology greatly reduces the complexity of driving, and its functions include lane monitoring, emergency braking, stability control, etc. ADAS is the first step towards driverless driving. To realize driverless driving, ADAS needs to be popularized first.
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