Projection module, three-dimensional scanning system and focusing device

Abstract

The utility model discloses a projection module, a three-dimensional scanning system and a focusing device.The projection module comprises an LED light source, a collimating lens, an optical mask and a projection lens which are arranged in sequence, and the LED light source is arranged on the focal plane of the collimating lens and used for emitting divergent beams; the collimating lens is arranged on a light emitting path of the LED light source and is used for focusing the divergent light beam emitted by the LED light source to obtain a focused light beam; the optical mask comprises a substrate engraved with a preset pattern, and the preset pattern on the substrate is arranged on a focal plane of the projection lens and is used for shaping the focused light beam to obtain a structured light pattern; and the projection lens is used for amplifying the structured light pattern and projecting the structured light pattern to a target area to form a structured light field. The projection module provided by the utility model can realize short-distance object recognition, and is low in development and manufacturing cost.

Description

Technical Field

[0001] The present application relates to the field of optical technology, and in particular to a projection module, a three-dimensional scanning system and a focusing device. Background Art

[0002] In the prior art, a structured light 3D scanning system includes a projection module, a receiving module and a processing chip. The basic principle of achieving 3D measurement is to project a speckle pattern onto a target area through the projection module. The speckle pattern is reflected by the target area and then collected by the receiving module to obtain a speckle image. The processing chip processes the speckle image to obtain 3D information of the target area.

[0003] As the core equipment of the structured light 3D scanning system, the projection module usually includes optical elements such as a VCSEL array light source, a collimating lens and a diffractive optical element. The VCSEL array light source is used to emit a light beam to the collimating lens. The light beam collimated by the collimating lens is transmitted to the diffractive optical element. The diffractive optical element replicates the focused light beam to form a speckle pattern and projects it to the target area. The speckle image is collected by the receiving module after being reflected back from the target area, so as to further obtain the 3D information of the target area through the processing chip.

[0004] However, due to the current technological level, the area and power consumption of the VCSEL array light source are limited, so the number of light source points will not be too dense, resulting in a low density of the projected speckle pattern. In addition, the laser divergence angle of a single light source of the VCSEL array light source is large, and the spot size after collimation by the collimating lens is also difficult to reduce, further limiting the density of the speckle pattern projected by the projection module. Secondly, the VCSEL array light source is generally in the near-infrared band, which is difficult to meet the needs of speckle patterns in other bands. In addition, the projection module based on the VCSEL array light source is also constrained by the structured light algorithm and the distance from the receiving module, so that its working distance is usually between 0.2-8 meters, making it difficult to achieve closer recognition.

[0005] Therefore, there is an urgent need to improve the above-mentioned projection module. Summary of the invention

[0006] The present application provides a projection module, a three-dimensional scanning system and a focusing device, aiming to solve some of the problems mentioned in the background technology of the related art.

[0007] In order to solve the above technical problems, an embodiment of the present application provides a projection module, including a circuit board, an LED light source, a collimating lens, an optical mask and a projection lens, wherein: the LED light source is arranged on the focal plane of the collimating lens, and is used to emit a divergent light beam; the collimating lens is arranged on the light output path of the LED light source, and is used to focus the divergent light beam emitted by the LED light source to obtain a focused light beam; the optical mask includes a substrate engraved with a preset pattern, and the preset pattern on the substrate is arranged on the focal plane of the projection lens, and is used to shape the focused light beam to obtain a structured light pattern; the projection lens is used to amplify the structured light pattern and project it to a target area to form a structured light field.

[0008] The present application directly depicts a preset pattern on an optical mask through a photolithography process, so that structured light field projection can be achieved by only using an LED light source and an optical mask with a preset pattern. Compared with using a VCSEL array light source and a diffractive optical element to achieve structured light field projection, its development and manufacturing cost is lower. In addition, the projection module provided by the present application can project structured light patterns of different wavelengths by simply replacing LED light sources of different wavelengths, so that the light source of the projection module is not limited to a VCSEL array light source of near-infrared wavelength, and mass production is easy to achieve. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0010] Figure 1 A schematic diagram of the structure of a three-dimensional scanning system provided according to the present application;

[0011] Figure 2 A schematic diagram of the structure of a projection module provided according to the present application;

[0012] Figure 3 A schematic diagram of a design of an optical mask provided according to the present application;

[0013] Figure 4 A schematic diagram of a design of an outgoing light path provided in the present application;

[0014] Figure 5 A schematic diagram of the structure of a focusing device for quality inspection of a projection module provided by the present application;

[0015] Figure 6 A partial schematic diagram of detecting projection speckle of a projection module provided in accordance with the present application. DETAILED DESCRIPTION

[0016] In order to facilitate the understanding of the present application, the present application will be described more comprehensively with reference to the relevant drawings below. The preferred embodiments of the present application are provided in the drawings. However, the present application can be implemented in many other different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0017] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0018] It should be understood that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0019] It should also be noted that, in the embodiments of the present application, the same figure mark is used to represent the same component or the same part. For the same parts in the embodiments of the present application, the figure may only use one of the parts or components as an example to mark the figure mark. It should be understood that the figure marks also apply to other identical parts or components.

[0020] Figure 1 This is a structural schematic diagram of a three-dimensional scanning system provided in the present application, wherein the depth camera includes a projection module 10, a receiving module 20 and a processing chip 30, wherein the projection module 10 is used to project a structured light pattern beam to a target area to form a structured light field in the target area, the receiving module 20 is used to collect the light beam reflected back from the target area to generate an image, and the processing chip 30 is used to process the corresponding image to obtain three-dimensional information of the target area, such as any one or more three-dimensional information such as depth, point cloud, height, parallax, etc.

[0021] In one embodiment, the projection module 10 includes an LED light source, a collimating lens and an optical mask, wherein the LED light source is used to emit a divergent light beam, and the collimating lens is used to focus the divergent light beam to obtain a focused light beam, wherein the focused light beam includes a parallel light beam or a nearly parallel light beam, and after the focused light beam passes through the optical mask, it forms a structured light pattern beam and is projected onto a target area, thereby forming a structured light field in the target area.

[0022] In one embodiment, the receiving module 20 includes a lens unit and an image sensor including multiple pixels, wherein the lens unit is used to receive the structured light pattern beam formed after being reflected by the target person and focus it on the corresponding pixel of the image sensor to generate a corresponding image. In this embodiment, the lens unit can be a single lens, or a lens group composed of multiple lenses, or any optical element that can achieve focusing function, such as a microlens array, liquid crystal, super lens, etc.; the image sensor can be an array image sensor composed of a charge coupled device (CCD), a complementary metal oxide semiconductor (CMOS), an avalanche diode (AD), a single photon avalanche diode (SPAD), etc., and the size of the array represents the resolution.

[0023] Furthermore, the processing chip 30 processes the image collected by the receiving module 20 based on the structured light principle or the time-of-flight principle to obtain the depth information of the target area. In this embodiment, the processing chip 30 and the receiving module 20 are independently set or integrated, and they communicate wirelessly or wired; the processing chip 30 can be an independent dedicated circuit, such as a dedicated SOC chip, FPGA chip, ASIC chip, etc. composed of a CPU, a memory, a bus, etc., or a general processing circuit. For example, when it is integrated into a smart terminal such as a mobile phone, a TV, a computer, a scanner, etc., the processing circuit in the terminal can be used as at least a part of the processing device.

[0024] Figure 2 The detailed structural diagram of a projection module 10 provided according to the present application is shown. The projection module 10 includes a circuit board 101, an LED light source 102, a collimating lens 103, an optical mask 104 and a projection lens 105 arranged in sequence, wherein the circuit board 101 is used to power the LED light source 102 and / or control the working state of the LED light source 102; the LED light source 102 is arranged on the focal plane of the collimating lens 103, and is used to emit a divergent light beam; the collimating lens 103 is arranged on the light output path of the LED light source 102, and is used to focus the divergent light beam emitted by the LED light source 102 to obtain a focused light beam; the optical mask 104 includes a substrate engraved with a preset pattern, and the preset pattern on the substrate is arranged on the focal plane of the projection lens 105, so as to shape the focused light beam to obtain a structured light pattern and transmit it to the projection lens 105; the projection lens 105 is coaxially arranged with the collimating lens 103, and is used to amplify the structured light pattern and project it to the target area, so as to form a structured light field in the target area.

[0025] This embodiment directly engraves a preset pattern on an optical mask through a photolithography process, thereby realizing structured light field projection using only an LED light source and an optical mask engraved with a preset pattern. Compared with using a VCSEL array light source and a diffractive optical element to realize structured light field projection, its development and manufacturing cost is lower.

[0026] In one embodiment, the circuit board 101 and the LED light source 102 are electrically connected via a bonding conductor. Specifically, the bonding conductor includes solder paste, and the present application accurately prints the solder paste onto the circuit board 101 based on the SMT process so that the LED light source 102 is directly soldered onto the circuit board 101 via the solder paste, so that both the positive and negative electrodes of the LED light source 102 are electrically connected to the circuit board 101, thereby powering the LED light source 102 and controlling the working state of the LED light source 102 through the circuit board 101.

[0027] The circuit board 101 is preferably an aluminum substrate circuit board. The circuit board 101 communicates with the processing chip 30 in the three-dimensional scanning system via wireless or wired means. The two can be independently set or integrated on the same circuit board, so that the processing chip 30 in the three-dimensional scanning system indirectly controls the working state of the LED light source 102 through the circuit board 101.

[0028] The LED light source 102 includes any one or more combinations of LED light sources of different wavelengths, such as near-infrared LED light sources, ultraviolet LED light sources, blue LED light sources or green LED light sources. By simply replacing LED light sources of different wavelengths, it is possible to project structured light patterns of different wavelengths, so that the light source of the projection module is not limited to a VCSEL array light source of near-infrared wavelength.

[0029] The collimating lens 103 is disposed on the light path of the LED light source 102, and is used to focus the divergent light beam emitted by the LED light source 102, so as to compress the divergence angle of the divergent light beam, obtain a parallel light beam or a focused light beam close to a parallel light beam, and propagate it to the optical mask 104, so as to make the light beam passing through the optical mask 104 more uniform. It should be understood that the collimating lens 103 can be one or more convex lenses or an optical lens with a focusing function such as a microlens array, a liquid crystal, a super lens, or any other optical element that can achieve a focusing function, and the present application does not limit this.

[0030] The optical mask 104 includes a substrate, on which a preset pattern is engraved through a photolithography process to divide the substrate into a light-transmitting area and a light-impermeable area. When the focused light beam obtained by the collimating lens 103 is propagated to the optical mask 104, the focused light beam passes through the light-transmitting area on the substrate in the optical mask 104, thereby forming a structured light pattern on the light-emitting surface of the optical mask 104.

[0031] In one embodiment, the preset pattern engraved on the substrate can be designed according to the actual situation. The specific design principle is to design a pattern that meets the preset requirements according to the preset input light beam and the preset output light beam, and to make the pattern on the substrate through photolithography technology to form the optical mask required in this embodiment. That is, the divergent light beam emitted by the LED light source 102 is used as the preset input light beam, and the structured light field of the required density is used as the preset output light beam. The pattern on the substrate is designed according to the two to obtain an optical mask 104 that meets the requirements, such as Figure 3 As shown, the white area is the opaque area, and the black spot is the translucent area, so that the divergent light beam emitted by the LED light source 102 can form a high-density structured light pattern after passing through the optical mask 104 engraved with the pattern, and then when the structured light pattern is projected to the target area through the projection lens 105, a structured light field of the required density is formed.

[0032] The projection lens 105 is used to magnify the structured light pattern, and is preferably any one or more combinations of optical elements with magnification functions such as an objective lens, a fixed-focus lens or a zoom lens, a super lens, and a liquid crystal. In this embodiment, in addition to obtaining a high-density structured light field by changing the preset pattern on the optical mask 104, a high-density structured light field can also be obtained by adjusting the focal length of the projection lens 105. Specifically, the principle of obtaining a high-density pattern by adjusting the focal length of the projection lens 105 is that when the focused light beam passes through the optical mask 104 to form a structured light pattern including multiple two-dimensional patterns, different focal lengths of the projection lens 105 will result in two-dimensional patterns of different sizes, that is, the spacing between the two-dimensional patterns in the different structured light patterns obtained under the projection lenses 105 with different focal lengths is different, and the density of the two-dimensional patterns in the structured light pattern is different. The two-dimensional pattern can be a speckle pattern, a stripe pattern, a linear pattern or other forms. In other words, when the focused light beam passes through the optical mask 104 engraved with the pattern, a structured light pattern is formed. Compared with a projection module not equipped with a projection lens 105, each two-dimensional pattern in the structured light pattern passing through the projection lens 105 will be magnified and projected toward the target area, thereby reducing the spacing between each two-dimensional pattern, and forming a high-density structured light field in the target area.

[0033] It should be noted that when the structured light pattern is a speckle pattern, in order to ensure a high-density structured light field, the preset pattern on the optical mask and / or the focal length of the projection lens must meet the following requirements: after any speckle in the speckle pattern modulated by the optical mask and / or the projection lens is captured by the image sensor in the receiving module, the coverage area on the imaging surface of the image sensor is at least greater than 1 pixel unit, but it must be ensured that it does not exceed 4 pixel units; when the structured light pattern is a stripe pattern or a linear pattern, its high density depends on the spacing between each stripe or each line; the high density of the structured light pattern can be designed according to the actual application scenario, and this application does not impose any restrictions on this.

[0034] In addition, since the projection lens 105 is used to enlarge or reduce the structured light pattern, its focal length will constrain the distance at which the projection module 10 projects a clear structured light field. Therefore, by matching a suitable projection lens 105 to the projection module 10, the projection module 10 can achieve clear structured light field projection at a close distance, thereby further acquiring three-dimensional information of close objects.

[0035] In one embodiment, when the structured light pattern projected by the projection module 10 is a speckle pattern, if the processing chip 30 in the three-dimensional scanning system processes the image collected by the receiving module 20 based on the structured light principle, the speckle pattern needs to satisfy local irrelevance when being designed, that is, each sub-region in the pattern has a high uniqueness; if the processing chip 30 in the three-dimensional scanning system processes the image collected by the receiving module 20 based on the time-of-flight principle, there is no restriction on the speckle pattern projected by the projection module 10.

[0036] like Figure 2 As shown, the projection module 10 further includes a mounting bracket 106, which is a cavity with two ends opened, and is used to fix the circuit board 101, the collimating lens 103 and the optical mask 104 provided with the LED light source 102. Specifically, the circuit board 101 is fixed to the open side of one end of the mounting bracket 106 by screws and / or glue, and is enclosed with the mounting bracket 106 to form a receiving cavity with only one end open, and the LED light source 102 fixed to the circuit board 101 is just opposite to the opening of the mounting bracket 106. The collimating lens 103 and the optical mask 104 are sequentially arranged in the receiving cavity formed by the mounting bracket 106 and the circuit board 101 along the light output path of the LED light source 102 by glue and / or internal and external thread rotation matching. The installation distance between the collimating lens 103 and the LED light source 102 fixed on the circuit board 101 is exactly equal to the focal length of the collimating lens 103. The optical mask 104 is preferably arranged close to the light-emitting surface of the collimating lens 103 , and the two can be independently arranged or integrated, which can reduce the occupied space and make the projection module 10 miniaturized.

[0037] In one embodiment, the projection module 10 further includes a lens barrel 107, which is fixed to the opening of the other end of the mounting bracket 106 by means of screws and / or glue, and is used to fix the projection lens 105, so that the structured light pattern formed by the optical mask 104 can be magnified by the projection lens 105, thereby forming a structured light field in the target area. Specifically, the projection lens 105 is installed in the lens barrel 107 by means of glue and / or internal and external thread rotation, and the distance between the projection lens 105 and the optical mask 104 is equal to the focal length of the projection lens 105, that is, the preset pattern on the optical mask 104 is exactly located on the image side focal plane of the projection lens 105. According to the principle of reversible optical path, the structured light pattern beam formed by passing through the preset pattern on the optical mask 104 on the imaging surface is reversely projected to the target area in the object space after being magnified by the projection lens 105, thereby forming a clear structured light field.

[0038] Specific as Figure 4 As shown in the optical path, the divergent light beam emitted by the LED light source 102 is collimated by the collimating lens 103 to obtain a focused light beam, and the focused light beam propagates to the optical mask 104, and the optical mask 104 is divided into a left area and a right area with the central axis of the optical mask 104 as the boundary. In view of the fact that the preset pattern on the optical mask 104 is exactly located on the image focal plane of the projection lens 105, that is, when part of the focused light beam passes through the left area of ​​the optical mask 104, the light beam propagates to the right area of ​​the projection lens 105; when part of the focused light beam passes through the right area of ​​the optical mask 104, the light beam propagates to the left area of ​​the projection lens 105; when part of the focused light beam passes through the central axis of the optical mask 104, the light beam propagation path remains unchanged, thereby forming a clear structured light field in the target area after being magnified by the projection lens 105.

[0039] Furthermore, in order to ensure both the miniaturization of the projection module 10 and the optimal effect of projecting the structured light pattern, the focal length ratio of the collimating lens 103 and the projection lens 105 in the present application is preferably 1:1.

[0040] In order to ensure that the projection module 10 meets the preset quality requirements before leaving the factory, during the assembly process of the projection module 10, the present application also provides a focusing device for quality inspection of the projection module 10, such as Figure 5As shown, the focusing device includes a closed light box 501, a receiving test board (chart board) 502, an industrial camera 503 and a host computer 504. The closed light box 501 is an opaque black box that can avoid the influence of external light; the receiving test board (chart board) 502 is arranged in the inner cavity of the closed light box 501, and the closed light box 501 is vertically partitioned to form an upper space and a lower space that are independent of each other; the projection module 10 is placed on the bottom plane of the lower space, and the industrial camera 503 is placed on the top of the upper space. The projection module 10 is used to project a structured light pattern toward the receiving test board 502, and the industrial camera 503 is used to collect the structured light pattern on the receiving test board 502 to generate a structured light image, as shown in FIG. Figure 6 As shown; the host computer 504 is used to receive the structured light image and perform contrast and size detection on the structured light pattern in the structured light image, so as to determine whether the structured light pattern projected by the projection module 10 is qualified according to the detection results, so that each component in the projection module 10 is in the best position.

[0041] In one embodiment, the host computer 504 can be electrically connected to the projection module 10 and the industrial camera 503, power the projection module 10 and the industrial camera 503 and control the working status of the projection module 10 and the industrial camera 40; in another embodiment, the host computer 504 can only be electrically connected to the industrial camera 503, power the industrial camera 503 and control the working status of the industrial camera 503, while the projection module 10 is powered and controlled by another independent power supply and switch, and this application does not impose any restrictions on this.

[0042] Specifically, during the assembly of the projection module 10, the projection lens 105 and the lens barrel 107 are first assembled by internal and external thread assembly to obtain a lens assembly, the collimating lens 103 and the optical mask 104 are sequentially assembled on the inner cavity of the mounting bracket 106 by glue dispensing, the circuit board 101 welded with the LED light source 102 is installed on one end opening of the mounting bracket 106 by glue dispensing and screw locking, and the lens assembly is installed on the other end opening of the mounting bracket by glue dispensing and screw locking. After the projection module 10 is assembled, use the following method: Figure 4 The focusing device shown is subjected to quality inspection. If it is determined that the structured light pattern projected by the projection module 10 is qualified, the threaded rotation of the projection lens 105 and the lens barrel 107 in the projection module 10 is fixed by glue; if it is determined that the structured light pattern projected by the projection module 10 is unqualified, the projection lens 105 can be rotated to adjust the focusing distance of the projection lens 105 so that it and the optical mask 104 in the projection module 10 are in the best imaging position to project a qualified structured light pattern, and then the threaded rotation of the projection lens 105 and the lens barrel 107 in the projection module 10 is fixed by glue.

[0043] Furthermore, the focusing device also includes a moving platform located in the lower space, and the projection module 10 can be placed on the moving platform. The moving platform is used to drive the projection module 10 to move up and down in the vertical direction. After the projection lens 105 and the lens barrel 107 in the projection module 10 are fixed by glue and the threads are rotated, the projection module 10 is driven up and down by the moving platform to change its distance from the receiving test board 502, so that the distance between the projection module 10 and the receiving test board 502 is respectively the focusing distance of the projection lens, the maximum depth of field and the minimum depth of field of the projection module 10, and then it is determined whether the projected structured light pattern is qualified when the projection module 10 is in the above position.

[0044] Compared with the traditional projection module composed of optical elements such as VCSEL array light source, collimating lens and diffractive optical element, which needs to use AA (Auto Alignment) equipment for focusing and optical axis alignment, the projection module 10 provided in the present application uses LED light source and optical mask to realize structured light pattern projection. It does not need to consider the problem of optical axis alignment, and only needs to focus through a simple focusing device. There is no need to use AA equipment, and its assembly cost is reduced, which is easy to achieve mass production.

[0045] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A projection module, characterized in that: It includes an LED light source, a collimating lens, an optical mask and a projection lens arranged in sequence, wherein: The LED light source is disposed on the focal plane of the collimating lens and is used to emit a divergent light beam; The collimating lens is arranged on the light output path of the LED light source, and is used to focus the divergent light beam emitted by the LED light source to obtain a focused light beam; The optical mask comprises a substrate engraved with a preset pattern, wherein the preset pattern on the substrate is arranged on the focal plane of the projection lens and is used to shape the focused light beam to obtain a structured light pattern; The projection lens is used to magnify the structured light pattern and project it onto a target area to form a structured light field.

2. The projection module according to claim 1, characterized in that: The projection module also includes a circuit board, which is electrically connected to the LED light source via an adhesive conductor and is used to supply power to the LED light source and / or control the working state of the LED light source.

3. The projection module according to claim 2, characterized in that: The bonding conductor is solder paste, and the LED light source is directly soldered on the circuit board through the solder paste.

4. The projection module according to any one of claims 1 to 3, characterized in that: The collimating lens includes one or more convex lenses, microlens arrays, liquid crystals and superlenses, and is used to focus the divergent light beam emitted by the LED light source to compress the divergence angle of the divergent light beam to obtain a parallel light beam or a focused light beam that is close to a parallel light beam.

5. The projection module according to any one of claims 1 to 3, characterized in that: The preset pattern divides the substrate into a light-transmitting area and a light-impermeable area. When the focused light beam propagates to the optical mask, the focused light beam passes through the light-transmitting area on the substrate in the optical mask to form the structured light pattern on the light-emitting surface of the optical mask.

6. The projection module according to any one of claims 1 to 3, characterized in that: A high-density structured light field is obtained by changing the preset pattern on the optical mask or adjusting the focal length of the projection lens.

7. The projection module according to claim 6, characterized in that: When the structured light pattern is a speckle pattern, the preset pattern on the optical mask and / or the focal length of the projection lens need to satisfy the following requirements: the coverage area of ​​any speckle in the speckle pattern modulated by the optical mask and / or the projection lens on the imaging surface of the image sensor is at least greater than 1 pixel unit but not more than 4 pixel units.

8. The projection module according to claim 2 or 3, characterized in that: The projection module also includes a mounting bracket for fixing the circuit board provided with the LED light source, the collimating lens and the optical mask.

9. The projection module according to claim 8, characterized in that: The optical mask is arranged closely to the light-emitting surface of the collimating lens, and the optical mask and the collimating lens are independently arranged or integrated.

10. The projection module according to claim 8, characterized in that: The mounting bracket is a cavity with openings at both ends. The circuit board is fixed to an open side of one end of the mounting bracket by screws and / or glue, and is enclosed with the mounting bracket to form a accommodating cavity with only one end open, so that the LED light source fixed to the circuit board is exactly opposite to the opening of the mounting bracket.

11. The projection module according to claim 9, characterized in that: The collimating lens and the optical mask are sequentially arranged in the accommodating cavity formed by the mounting bracket and the circuit board along the light output path of the LED light source by means of glue dispensing and / or rotational matching of internal and external threads.

12. The projection module according to claim 8, wherein: The projection module also includes a lens barrel, which is arranged on the other end opening of the mounting bracket by means of screws and / or glue, and is used for the projection lens.

13. The projection module according to claim 12, wherein: The projection lens is installed in the lens barrel by means of glue dispensing and / or rotational matching of internal and external threads.

14. The projection module according to any one of claims 1 to 3, characterized in that: When part of the focused light beam passes through the left area of ​​the optical mask, the part of the light beam propagates to the right area of ​​the projection lens; when part of the focused light beam passes through the right area of ​​the optical mask, the part of the light beam propagates to the left area of ​​the projection lens; when part of the focused light beam passes through the central axis of the optical mask, the light beam propagation path remains unchanged.

15. The projection module according to any one of claims 1 to 3, characterized in that: The focal length ratio of the collimating lens to the projection lens is 1:

1.

16. A three-dimensional scanning system, characterized in that: The device comprises a projection module, a receiving module and a processing chip as claimed in any one of claims 1 to 15, wherein: The projection module is used to project a structured light pattern beam to a target area to form a structured light field in the target area; The receiving module is used to collect the light beam reflected from the target area to generate an image; The processing chip is used to process the corresponding image to obtain the three-dimensional information of the target area.

17. A focusing device, characterized in that: Used to perform quality inspection on the projection module according to any one of claims 1 to 15, the focusing device comprising: Closed light box to avoid the influence of external light; A receiving test board is arranged in the inner cavity of the closed light box, and the closed light box is vertically partitioned to form an upper space and a lower space which are independent of each other; An industrial camera is placed on the top of the upper space, the projection module is placed on the bottom plane of the lower space, the projection module is used to project the structured light pattern toward the receiving test board, and the industrial camera is used to collect the structured light pattern on the receiving test board to generate a structured light image; The host computer is used to receive the structured light image and perform contrast and size detection on the structured light pattern in the structured light image, and determine whether the structured light pattern projected by the projection module is qualified according to the detection result.

18. The focusing device according to claim 17, characterized in that: The focusing device also includes a moving platform located in the lower space, which is used to be placed on the projection module to drive the projection module to move up and down in the vertical direction, so that the distance between the projection module and the receiving test plate is respectively the focusing distance of the projection lens, the maximum depth of field and the minimum depth of field of the projection module, so as to judge whether the structured light pattern projected when the projection module is in the corresponding position is qualified.

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