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 multi-color light source, a collimating lens, an optical mask and a projection lens which are arranged in sequence, and the LED multi-color light source comprises at least two LED chips with different wavelengths and is used for emitting divergent beams with different wavelengths; the collimating lens is used for focusing the divergent light beams emitted by the LED multi-color light source to obtain focused light beams; 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. According to the projection module provided by the invention, the miniaturization of the projection module is facilitated, so that the projection module has different working field depths, the application requirements of different scenes are met, and the practicability of the projection module in different application fields is greatly enriched.

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, the VCSEL array light source in the traditional projection module is usually in the near-infrared band. When it encounters a light-absorbing object such as black or an object with a rough texture, the infrared light projected by the projection module will be absorbed, resulting in missing data scanned by the 3D scanning system. On the other hand, the working depth of field of the projection module in the 3D scanning system is generally limited by the depth of field of the light source and the projection lens of a single wavelength. If multiple light sources of different wavelengths are integrated into the 3D scanning system, the cost and structural complexity of the system will increase.

[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, comprising an LED multi-color light source, a collimating lens, an optical mask and a projection lens arranged in sequence, wherein: the LED multi-color light source comprises at least two LED chips with different wavelengths, which are used to emit divergent light beams of different wavelengths; the collimating lens is used to focus the divergent light beams emitted by the LED multi-color 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 the focal plane of the projection lens, which 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] This application can realize the switching of multi-wavelength light beams through a single light source, which is conducive to the miniaturization of the projection module, so that the projection module has different working depths of field, meets the application requirements of different scenes, and greatly enriches the practicality of the projection module in different application fields. In addition, this application only uses LED multi-color light sources and optical masks engraved with preset patterns to realize multi-wavelength structured light field projection. Compared with the use of VCSEL array light sources and diffractive optical elements to realize single-wavelength structured light field projection, it is easy to achieve mass production and has low development and manufacturing costs. 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 This is a schematic diagram of the structure of an LED multi-color light source provided according to the present application;

[0013] Figure 4 A schematic diagram of a design of an optical mask provided according to the present application;

[0014] Figure 5 A schematic diagram of the optical path of light of different wavelengths passing through a projection lens to generate defocus according to the present application;

[0015] Figure 6 A schematic diagram of a design of an outgoing light path provided in the present application;

[0016] Figure 7 A schematic diagram of the structure of a focusing device for quality inspection of a projection module provided by the present application;

[0017] Figure 8 A partial schematic diagram of detecting projection speckle of a projection module provided in accordance with the present application. DETAILED DESCRIPTION

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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 of a corresponding wavelength to a target area according to application scenario requirements 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.

[0023] In one embodiment, the projection module 10 includes an LED multi-color light source, a collimating lens and an optical mask, wherein the LED multi-color light source is used to emit divergent light beams of different wavelengths respectively, and the collimating lens is used to focus the divergent light beams of different wavelengths to obtain corresponding focused light beams, and the focused light beams include parallel light beams or nearly parallel light beams. After the focused light beam passes through the optical mask, it forms a structured light pattern beam of different wavelengths and is projected onto the target area, thereby forming a structured light field of different wavelengths in the target area.

[0024] In some embodiments, the receiving module 20 includes a lens unit and at least one 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.

[0025] In one embodiment, when the receiving module 20 includes more than one image sensor, the image sensor is a black and white image sensor, that is, it does not include a filter. The black and white image sensor can collect structured light patterns of different wavelengths projected by the projection module 10 and generate corresponding images; in another embodiment, when the receiving module 20 includes more than two image sensors, the receiving module also includes a filter arranged between the image sensor and the lens unit, and the filter filters the remaining wavelength band light beams except the light beam projected by the projection module 10, and only allows the light beam projected by the projection module 10 to enter the image sensor for imaging, thereby avoiding interference from stray light.

[0026] Furthermore, the processing chip 30 processes the image collected by the receiving module 20 based on the structured light principle, stereo matching principle or 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 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.

[0027] Figure 2The 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 multicolor 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 multicolor light source 102 and / or control the working state of the LED multicolor light source 102; the LED multicolor light source 102 is arranged on the focal plane of the collimating lens 103, and is used to emit divergent light beams of different wavelengths in a time-sharing or simultaneous manner; the collimating lens 103 is arranged on the light-emitting path of the LED multicolor light source 102, and is used to focus the divergent light beams emitted by the LED multicolor 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 used to amplify the structured light pattern and project it to a target area, so as to form a structured light field in the target area.

[0028] The present application can realize the switching of multi-wavelength light beams through a single light source, which is conducive to the miniaturization of the projection module 10 and meets the application requirements of different scenes, greatly enriching the practicality of the projection module in different application fields. In addition, the present application only uses LED multi-color light sources and optical masks engraved with preset patterns to realize multi-wavelength structured light field projection. Compared with the use of VCSEL array light sources and diffractive optical elements to realize single-wavelength structured light field projection, it is easy to achieve mass production and has low development and manufacturing costs.

[0029] The LED multicolor light source 102 includes at least two LED chips with different wavelengths integrated on the same chip, such as Figure 3 As shown, two LED chips 1021 with different wavelengths are integrated on the same chip 1020. Each LED chip can work independently or in parallel. The LED chips with different wavelengths have a common positive electrode and a separate negative electrode. The LED multi-color light source 102 is controlled to emit divergent light beams of different wavelengths by independently controlling the negative electrode of the LED chip. The LED multi-color light source 102 includes any one or more combinations of LED chips with different wavelengths, such as near-infrared LED chips, ultraviolet LED chips, blue LED chips or green LED chips. By simply replacing LED chips with different wavelengths, it is possible to project structured light patterns with different wavelengths, so that the light source of the projection module is not limited to the VCSEL array light source with near-infrared wavelengths.

[0030] The circuit board 101 includes a power module and a plurality of switch modules, the positive electrode of the power module is electrically connected to the common positive electrode of each LED chip in the LED multicolor light source 102, and the independent negative electrode of each LED chip in the LED multicolor light source 102 is electrically connected to the negative electrode of the power module through the switch module, and the switch module includes a circuit switch or a transistor. When any switch module is turned on, the LED chip electrically connected to the turned-on switch module will emit a divergent light beam. In the present application, the circuit board 101 is preferably an aluminum substrate circuit board.

[0031] In one embodiment, the LED multicolor light source 102 is electrically connected to the circuit board 101 through a bonding conductor. Specifically, the bonding conductor includes solder paste, and the present application accurately prints the solder paste on the circuit board 101 based on the SMT process so that the LED multicolor light source 102 is directly soldered on the circuit board 101 through the solder paste, so that the common positive electrode of the LED multicolor light source 102 is soldered to the positive electrode of the power module on the circuit board 101, and the independent negative electrodes of the LED multicolor light source 102 are respectively soldered to different switch switching modules to indirectly achieve electrical connection with the negative electrode of the power module, thereby powering the LED multicolor light source 102 and controlling the working state of the LED multicolor light source 102 through the circuit board 101.

[0032] It should be noted that the circuit board 101 communicates with the processing chip 30 in the three-dimensional scanning system via wireless or wired means, and 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 multi-color light source 102 through the circuit board 101.

[0033] The collimating lens 103 is disposed on the light-emitting path of the LED multicolor light source 102, and is used to focus the divergent light beams emitted by the LED multicolor light source 102, respectively, to compress the divergence angle of the divergent light beams, obtain parallel light beams or focused light beams close to parallel light beams, and propagate to the optical mask 104, so that the light beams passing through the optical mask 104 are more uniform. It should be understood that the collimating lens 103 can be one or more convex lenses or any optical element that can realize the focusing function, such as a microlens array, liquid crystal, super lens, etc., and the present application does not limit this.

[0034] 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.

[0035] 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 beam and the preset output 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 multi-color light source 102 is used as the preset input beam, and the structured light pattern of the required density is used as the preset output 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 4 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 multi-color light source 102 can form a structured light pattern of required density 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 required density is formed.

[0036] 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 structured light field of a desired density by changing the preset pattern on the optical mask 104, a structured light field of a desired density can also be obtained by adjusting the focal length of the projection lens 105. Specifically, the principle of obtaining a structured light field of a desired density 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 a plurality of 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 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 to form a structured light pattern, compared to 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 structured light field of the desired density in the target area.

[0037] Furthermore, since the projection lens 105 is used to enlarge or reduce the structured light pattern, if only a single-wavelength light source is used, the focal length of the projection lens 105 will limit the working depth of field of the projection module 10, and constrain the projection module 10 to project a clear structured light field within a certain distance range. For this reason, the present application uses an LED multi-color light source 102 to emit light beams of different wavelengths, and according to the optical property of the projection lens 105 itself that the axial chromatic aberration has, when light beams of different wavelengths pass through the projection lens 105, defocusing will occur, that is, the focal points of light beams of different wavelengths are not on the same plane when passing through the projection lens 105, such as Figure 5As shown, the projection module 10 has different working depths of field, thereby broadening the working range of the three-dimensional scanning system using the projection module 10 in the present application.

[0038] 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.

[0039] In addition, when the structured light pattern is a speckle pattern, in order to ensure that the structured light field with the required density is 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: any speckle in the structured light field modulated by the optical mask and / or the projection lens must cover an area of ​​at least more than 1 pixel unit on the imaging surface of the image sensor after being captured by the image sensor in the receiving module, 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.

[0040] like Figure 2 As shown, the projection module 10 further includes a mounting bracket 106, which is a cavity with openings at both ends, and is used to fix the circuit board 101, the collimating lens 103, and the optical mask 104 provided with the LED multi-color 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 multi-color light source 102 fixed to the circuit board 101 is exactly 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 path of the LED multi-color light source 102 by glue and / or internal and external thread rotation matching. The installation distance between the collimating lens 103 and the LED multi-color 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.

[0041] 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.

[0042] Specific as Figure 6 As shown in the optical path, the divergent light beam emitted by the LED multicolor 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.

[0043] 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.

[0044] 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 7As shown, the focusing device includes a closed light box 701, a receiving test board (chart board) 702, an industrial camera 703 and a host computer 704. The closed light box 701 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 701, and the closed light box 701 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 703 is placed on the top of the upper space. The projection module 10 is used to project structured light patterns of different wavelengths onto the receiving test board 702 in sequence, and the industrial camera 703 is used to respectively collect structured light patterns of different wavelengths on the receiving test board 702 to generate corresponding structured light images. The structured light image under a single wavelength is shown as follows. Figure 8 As shown; the host computer 704 is used to receive the structured light image and perform contrast and size detection on the structured light pattern in the structured light image at different wavelengths, so as to determine whether the structured light pattern of each wavelength 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.

[0045] In one embodiment, the host computer 704 can be electrically connected to the projection module 10 and the industrial camera 703 to power the projection module 10 and the industrial camera 703 and control the working status of the projection module 10 and the industrial camera 40; in another embodiment, the host computer 704 can only be electrically connected to the industrial camera 703 to power the industrial camera 703 and control the working status of the industrial camera 703, 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.

[0046] 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 multicolor 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 4The 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.

[0047] 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 702, 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 judged whether the different wavelength structured light patterns projected when the projection module 10 is in the above position are qualified.

[0048] 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 multi-color light source and optical mask, which can not only realize the projection of structured light patterns of different wavelengths to meet the diversified needs of scenes, but also does not need to consider the problem of optical axis alignment. It only needs to focus through a simple focusing device, without the need to use AA equipment, and its assembly cost is reduced, and it is easy to achieve mass production.

[0049] 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 LED multicolor light source, collimating lens, optical mask and projection lens arranged in sequence, wherein: The LED multicolor light source includes at least two LED chips with different wavelengths, which are used to emit divergent light beams with different wavelengths; The collimating lens is used to focus the divergent light beam emitted by the LED multicolor 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 LED multi-color light source is arranged on the focal plane of the collimating lens. The LED multi-color light source also includes a chip. The at least two LED chips with different wavelengths are integrated on the same chip.

3. 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 multi-color light source through an adhesive conductor and is used to supply power to the LED multi-color light source and / or control the working state of the LED multi-color light source.

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

5. The projection module according to claim 3, characterized in that: The circuit board includes a power module and multiple switch switching modules. The LED chips with different wavelengths have a common positive pole and separate negative poles. The positive pole of the power module is electrically connected to the common positive pole of each LED chip in the LED multi-color light source, and the independent negative pole of each LED chip in the LED multi-color light source is electrically connected to the negative pole of the power module through the switch switching module.

6. The projection module according to claim 5, characterized in that: The switch switching module includes a circuit switch or a transistor. When any switch switching module is turned on, the LED chip electrically connected to the turned-on switch switching module will emit a divergent light beam.

7. The projection module according to any one of claims 1 to 6, 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 multi-color 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.

8. The projection module according to any one of claims 1 to 6, 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.

9. The projection module according to any one of claims 1 to 6, 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.

10. The projection module according to claim 9, 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.

11. The projection module according to any one of claims 1 to 6, characterized in that: The projection lens has an optical property of axial chromatic aberration. When light beams of different wavelengths emitted by the LED multicolor light source pass through the projection lens, the focal points of the light beams are not located on the same plane, so that the projection module has different working depths of field.

12. The projection module according to any one of claims 4 to 6, characterized in that: The projection module also includes a mounting bracket for fixing the circuit board provided with the LED multi-color light source, the collimating lens and the optical mask.

13. The projection module according to claim 12, wherein: 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.

14. The projection module according to claim 12, wherein: The mounting bracket is a cavity with openings at both ends. The circuit board is fixed to the 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 multi-color light source fixed to the circuit board is exactly opposite the opening of the mounting bracket.

15. The projection module according to claim 14, wherein: 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 multi-color light source through the installation method of dispensing glue and / or rotating matching of internal and external threads.

16. The projection module according to claim 12, 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.

17. The projection module according to claim 16, wherein: The projection lens is installed in the lens barrel by means of glue dispensing and / or rotational matching of internal and external threads.

18. The projection module according to any one of claims 1 to 6, 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.

19. The projection module according to any one of claims 1 to 6, characterized in that: The focal length ratio of the collimating lens to the projection lens is 1:

1.

20. 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 19, wherein: The projection module is used to project a structured light pattern beam of a corresponding wavelength to a target area according to application scenario requirements 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.

21. A focusing device, characterized in that: Used to perform quality inspection on the projection module according to any one of claims 1 to 19, 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, and the projection module is placed on the bottom plane of the lower space. The projection module is used to project structured light patterns of different wavelengths onto the receiving test board, and the industrial camera is used to collect the structured light patterns on the receiving test board to generate corresponding structured light images. 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 patterns of different wavelengths projected by the projection module are qualified according to the detection results.

22. The focusing device according to claim 21, 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 patterns of different wavelengths projected when the projection module is in the corresponding position are qualified.

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