Structured light projection optical device

Abstract

The utility model provides a structured light projection optical device, which is sequentially arranged along a propagation path of a light beam: a light source for emitting a divergent light beam; the collimating lens group is used for converting the divergent light beams into parallel light beams; the dodging sheet is used for performing diffraction dodging on the parallel light beams to obtain illumination light beams; the negative cylindrical lens is used for shaping a light spot of the illumination light beam, so that the light spot reaches a proper length-width ratio; the reflector is used for reflecting the shaped illumination light beam; the illumination relay assembly converges the reflected light beams, and the reflected light beams are refracted by an internal prism and then irradiate on the DMD light modulator at a proper incident angle; the DMD light modulator displays and projects a structured light pattern based on the light beam of the incident angle; the projection lens is used for projecting the structured light pattern on a projection surface; the light source, the collimating lens group, the dodging sheet and the negative cylindrical lens are sequentially arranged on the same center line along a light path; the equivalent image plane of the DMD light modulator, the plane where the normal of the optical axis of the projection lens is located and the projection plane intersect on the same straight line, and the light path structure meets the Gremer's law.

Description

Technical Field

[0001] The present application relates to the field of optical detection, and in particular to a structured light projection optical device. Background Art

[0002] With the rapid development of current science and technology, all walks of life have entered an era of industrialization and standardization. In the current era, the two-dimensional information of parts can no longer meet today's manufacturing needs. High-precision three-dimensional dimension detection of key parts through advanced measurement technology has become the key to the development of industries such as industrial manufacturing automation, industrial inspection automation, high-precision 3D printing, and machine vision AI inspection.

[0003] Three-dimensional information detection technology is divided into contact three-dimensional detection and non-contact three-dimensional detection according to whether the test instrument is in contact with the object to be tested. For traditional contact three-dimensional detection technology, a probe-type coordinate measuring instrument is generally used for detection. This detection method is prone to scratches, low detection efficiency and low precision due to the direct contact of the instrument probe with the object to be tested. In addition, due to the huge size of the measuring equipment, it is easily subject to various restrictions in the manufacturing industry, so it is impossible to achieve accurate and efficient detection in today's production and manufacturing. In non-contact three-dimensional detection technology, optical measurement technology has the advantages of non-contact, high precision and efficiency, and adaptability to complex working conditions. Optical measurement technology has excellent adaptability when facing the detection of complex surfaces. Structured light three-dimensional detection technology is a common optical means for three-dimensional detection of objects. Structured light is a specific pattern light with certain coded information. The structured light is projected on the surface of the object to be tested through projection technology, and the modulated light reflected back from the object to be tested is collected by imaging instruments such as cameras. The surface information of the object to be tested is determined by analyzing the image data and comparing it with the calibration data model.

[0004] Structured light 3D detection generally consists of two parts. The first part is the lighting part, which uses a projection device to project point structured light, line structured light or surface structured light with specific information onto the surface of the object to be tested. The second part is generally a CCD camera or a CMOS camera, which receives the reflected light signal from the surface of the object to be tested. After receiving the modulated light signal, the camera converts the photoelectric signal and transmits the digital signal to the computer. After calculation by the preset structured light demodulation algorithm, the 3D information of the object surface is calculated.

[0005] The structured light projection optical devices currently on the market have low output luminous flux, large size, and the spatial position of the optical device and the projection surface is parallel. When multiple optical devices need to be applied and the camera needs to be perpendicular to the detection surface, clear projection of the entire projection surface cannot be achieved. Summary of the invention

[0006] The utility model provides an optical device for structured light projection, which solves the problems of low light output flux, large volume, high manufacturing cost, short life and difficult layout of the existing optical device.

[0007] In order to achieve the above-mentioned purpose, the utility model provides an optical device, comprising: a light source, a collimating lens group, a light homogenizer, a negative cylindrical lens, a reflector, an illumination relay assembly, a DMD light modulator and a projection lens arranged in sequence along the optical path. The light source emits a divergent light beam; the collimating lens group converts the divergent light beam emitted by the light source into a parallel light beam; the light homogenizer diffracts the parallel light beam through the fine microstructure on the surface to obtain an illumination light beam; the negative cylindrical lens shapes the light spot of the illumination light beam so that the light spot reaches a suitable aspect ratio; the reflector reflects the shaped illumination light beam to change the light path direction of the illumination light beam and reduce the volume of the device. The illumination relay assembly converges the reflected light beam, refracts it through the internal prism, and then irradiates it on the DMD light modulator at a suitable incident angle; the DMD light modulator displays a structured light pattern based on the light beam at the incident angle; the projection lens projects the structured light pattern onto the projection surface; the light source, collimating lens group, homogenizer and negative cylindrical lens are arranged in sequence on a center line; there is an angle between the mirror normal of the reflector and the center line of the optical axis; the equivalent image plane of the DMD light modulator, the plane where the normal line of the optical axis of the projection lens is located and the projection surface intersect in a straight line, so that the optical path structure satisfies Sham's law.

[0008] In some embodiments, the light source 1 is a monochromatic LED, including a white light LED, a red light LED, a green light LED or a blue light LED. Adding the light source 1 to the optical device can realize active projection imaging of the DMD light modulator 8.

[0009] In some embodiments, the collimating lens group 2 is a two-piece lens group or a three-piece lens group, and the collimating lens group 2 includes a spherical lens and an aspherical lens. This can increase the output light flux of the device, facilitate compact layout, and reduce the size of the optical machine.

[0010] In some embodiments, the light homogenizer 3 includes a diffraction-type diffuser or a diffuse light homogenizer, so as to diffract and homogenize the parallel light beam to obtain an illumination light beam.

[0011] In some embodiments, the negative cylindrical lens 4 is a cylinder with an arc-shaped concave incident surface, which is used to pull the light spot of the illumination light beam in one direction so that the aspect ratio of the light spot is consistent with the aspect ratio of the mirror surface of the DMD light modulator 8. With the divergence and stretching effect of the arc-shaped concave surface on the incident light, the rectangular plane serves as the light exit surface, which has a shaping effect on the light spot.

[0012] The reflector 5 reflects the shaped light and then passes through the illumination relay assembly A. By changing the propagation path of the illumination light beam by the reflector 5, the size of the optical machine can be reduced.

[0013] In some embodiments, the illumination relay assembly A includes: a relay lens 6, which converges the reflected light beam; a prism group 7, which adjusts the incident angle of the converged light beam; the angle between the normal of the relay lens 6 and the light beam reflected by the reflector 5 can be adjusted; and there is an angle between the prism group 7 and the DMD light modulator 8. In this way, the area of ​​the reflected light beam can be reduced and the intensity of the light beam can be enhanced by converging the reflected light beam through the relay lens 6; the incident angle of the converged light beam is adjusted through the prism group 7, and the light beam is incident on the DMD light modulator 8 at a suitable illumination angle.

[0014] In some embodiments, the relay lens 6 includes a spherical lens or an aspherical lens, so as to increase the output light flux of the device, reduce the area of ​​the light beam, and enhance the intensity of the light beam.

[0015] In some embodiments, the prism group 7 includes a first right-angle prism and a second right-angle prism, and the two oblique surfaces of the first right-angle prism and the second right-angle prism are in contact with each other; the first right-angle prism adjusts the size and angle of the converged light beam incident on the DMD light modulator 8, and the second right-angle prism adjusts the size and angle of the structured light pattern projected by the DMD light modulator 8, and refracts the structured light pattern into the projection lens 9. In this way, the relay lens 6 and the prism group 7 can optimize the size and angle of the light beam incident on the DMD (image plane), and present the light in the effective light spot evenly, efficiently, and as clearly as possible on the DMD effective surface.

[0016] In some embodiments, the angle between the DMD light modulator 8 and the prism group 7 is α, 2<α<6 degrees, the first right-angle prism is a non-isosceles right-angle prism, the second right-angle prism is an isosceles right-angle prism, and the side length of the inclined surface of the first right-angle prism is smaller than that of the second right-angle prism. In this way, the size of the incident DMD (image plane) and the angle requirements are controlled.

[0017] In some embodiments, the projection lens 9 includes a plurality of different optical lenses, and projects the structured light pattern projected by the DMD light modulator 8 onto the projection surface 10 at a certain magnification, wherein the angle between the optical axis of the projection lens 9 and the normal of the projection surface 10 is β, 20<β<35 degrees. Thus, the angle between the optical axis of the projection lens 9 and the normal of the projection surface 10 is β, α and β satisfy the Sham's law of the optical path structure, and a comprehensive and clear image can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the multiple embodiments disclosed in this specification, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only the multiple embodiments disclosed in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] The following is a brief introduction to the drawings required for describing the embodiments or prior art.

[0020] Figure 1 A structural diagram of an optical device provided in an embodiment of the present application;

[0021] Figure 2a A schematic diagram of a rectangular negative cylindrical lens in an embodiment of the present application;

[0022] Figure 2b is a cross-sectional view of a negative cylindrical lens in an embodiment of the present application;

[0023] Figure 2c This is a light path diagram of a negative cylindrical lens in an embodiment of the present application;

[0024] Figure 2d This is a schematic diagram of the light spot shaping effect of the negative cylindrical lens in the embodiment of the present application;

[0025] Figure 2e is a schematic diagram of a circular negative cylindrical lens in an embodiment of the present application;

[0026] Figure 3 A schematic diagram of an optical device provided in Example 1 of the present application;

[0027] Figure 4 This is a schematic diagram of the optical path structure in Example 1 of the present application.

[0028] Figure ID

[0029] 1, light source; 2, collimating lens group; 3, light homogenizer; 4, negative cylindrical lens; 5, reflector; 6, relay lens; 7, prism group; 8, DMD light modulator; 9, projection lens; 10, projection surface; 32, two-piece collimating lens group; 71, first right-angle prism; 72, second right-angle prism. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0031] In the description of the embodiments of the present application, words such as "exemplary", "for example" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary", "for example" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary", "for example" or "for example" is intended to present related concepts in a concrete way.

[0032] In the description of the embodiments of the present application, the term "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, B exists alone, and A and B exist at the same time. In addition, unless otherwise specified, the term "multiple" means two or more. For example, multiple systems refers to two or more systems, and multiple terminals refers to two or more terminals.

[0033] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. The terms "include", "comprises", "has" and their variations all mean "including but not limited to", unless otherwise specifically emphasized.

[0034] The utility model provides an optical device for structured light projection, which solves the problems of low light output flux, large volume, high manufacturing cost, short life and difficult layout of the existing optical device.

[0035] In order to achieve the above-mentioned purpose, the utility model provides an optical device, comprising: a light source, a collimating lens group, a light homogenizer, a negative cylindrical lens, a reflector, an illumination relay assembly, a DMD light modulator and a projection lens arranged in sequence along the optical path. The light source emits a divergent light beam; the collimating lens group converts the divergent light beam emitted by the light source into a parallel light beam; the light homogenizer diffracts the parallel light beam through the fine microstructure on the surface to obtain an illumination light beam; the negative cylindrical lens shapes the light spot of the illumination light beam so that the light spot reaches a suitable aspect ratio; the reflector reflects the shaped illumination light beam to change the light path direction of the illumination light beam and reduce the volume of the device. The illumination relay assembly converges the reflected light beam, refracts it through the internal prism, and then irradiates it on the DMD light modulator at a suitable incident angle; the DMD light modulator displays a structured light pattern based on the light beam at the incident angle; the projection lens projects the structured light pattern onto the projection surface; the light source, collimating lens group, homogenizer and negative cylindrical lens are arranged in sequence on a center line; there is an angle between the mirror normal of the reflector and the center line of the optical axis; the equivalent image plane of the DMD light modulator, the plane where the normal line of the optical axis of the projection lens is located and the projection surface intersect in a straight line, so that the optical path structure satisfies Sham's law.

[0036] Figure 1 This is a structural diagram of an optical device provided in an embodiment of the present application. Figure 1 As shown, it includes a light source 1, a collimating lens group 2, a light beam homogenizer 3, a negative cylindrical lens 4, a reflector 5, an illumination relay component A, a DMD light modulator 8, and a projection lens 9 which are arranged in sequence along the light path.

[0037] The Lambertian distribution light beam emitted by the light source 1 passes through the collimating lens group 2 .

[0038] The light source 1 is a monochromatic LED, including a white light LED, red light, green light, or blue light.

[0039] The collimating lens group 2 converts the Lambertian distribution light beam emitted by the light source 1 into a parallel light beam. The collimating lens group 2 includes a spherical lens and an aspherical lens.

[0040] In some embodiments, the collimating lens group 2 is a three-piece lens group, which is composed of three superimposed spherical lenses. The interval between every two spherical lenses depends on the actual model of the device and the product performance design requirements.

[0041] In some embodiments, the collimating lens group 2 is a two-piece lens group, wherein the two-piece lens group consists of a spherical lens and an aspherical lens; due to the complex manufacturing process of the aspherical lens, this combination is more expensive than the three-piece lens group, and the interval between each two spherical lenses depends on the actual model of the device and the product performance design requirements.

[0042] In this embodiment, the collimating lens group 2 can be a combination of a spherical lens and / or an aspherical lens according to performance and cost requirements.

[0043] The parallel light beam passing through the collimating lens group 2 reaches the light homogenizer 3, and the light homogenizer 3 diffracts and homogenizes the parallel light beam to obtain an illumination light beam.

[0044] The surface of the light homogenizer 3 has fine microstructures, and the light is diffracted and homogenized by these fine microstructures. The light homogenizer 3 includes a diffraction type diffuser or other diffuse type light homogenizers.

[0045] The uniform light beam passing through the light homogenizer 3 reaches the negative cylindrical lens 4, and the negative cylindrical lens 4 shapes the light spot by stretching the uniform light beam in one direction, so that the illumination light spot reaches a suitable aspect ratio.

[0046] The negative cylindrical lens 4 is a column with an arc-shaped concave incident surface, and is used to pull up the light spot of the illumination light beam in one direction so that the aspect ratio of the light spot is consistent with the aspect ratio of the mirror surface of the DMD light modulator (8).

[0047] The negative cylindrical lens 4 can be a rectangular parallelepiped or a circular cylinder.

[0048] For example, Figure 2a A schematic diagram of a rectangular negative cylindrical lens is given. Figure 2aAs shown in the actual figure, the negative cylindrical lens 4 is a cylindrical lens with an arc-shaped concave light-entering surface and a rectangular light-emitting surface; the light-emitting surface of the negative cylindrical lens 4 is a rectangular plane with a length of B and a width of A. The values ​​of various parameters such as the object focal length, back intercept, center thickness, edge thickness and principal point of the negative cylindrical lens 4 depend on the actual model of the device and the product performance design requirements.

[0049] For example, Figure 2b As shown, the curvature radius of the light incident surface of the negative cylindrical lens 4 is 25.84.

[0050] For example, Figure 2c As shown, the optical path diagram shows the divergence and stretching effect of the arc-shaped concave surface on the incident light, and the rectangular plane serves as the light-emitting surface, which has a shaping effect on the light spot.

[0051] For example, Figure 2d As shown, the square black frame area in the schematic diagram of the light spot without the cylindrical lens is the light spot area without the cylindrical lens; the rectangular black frame area in the schematic diagram of the light spot after the negative cylindrical lens is stretched is the light spot area after the negative cylindrical lens is stretched.

[0052] For example, Figure 2e A schematic diagram of a circular negative cylindrical lens is given. In different application scenarios, the rectangular negative cylindrical lens and the circular negative cylindrical lens can be replaced.

[0053] It can be seen that the negative cylindrical lens 4 can shape the light spot of the illumination light beam so that the aspect ratio of the light spot is consistent with the aspect ratio of the mirror surface of the DMD light modulator 8.

[0054] In this embodiment, the uniformly lighted circular illumination light beam is subjected to spot shaping by a negative cylindrical lens 4 , and an elliptical spot is obtained after being pulled up in one direction. The elliptical spot has a suitable aspect ratio, which is consistent with the aspect ratio of the DMD optical modulator 8 .

[0055] The light source 1, the collimating lens group 2, the light homogenizing sheet 3, and the negative cylindrical lens 4 are sequentially arranged on the same center line nm along the optical path.

[0056] The reflector 5 reflects the shaped light and then passes through the illumination relay assembly A. By changing the propagation path of the illumination light beam by the reflector 5, the size of the optical machine can be reduced.

[0057] The reflector 5 may be arranged at a certain angle to the center line nm; in some embodiments, there is an angle between the normal line of the reflector surface of the reflector 5 and the center line of the optical axis; the angle is adjustable.

[0058] The reflected illumination light beam passes through the illumination relay assembly A, which converges and refracts the light beam and then is incident on the DMD light modulator 8 at a suitable illumination angle.

[0059] Specifically, the illumination relay assembly A includes a relay lens 6 and a prism group 7. The relay lens 6 converges the reflected light beam; the reflected light beam converges through the relay lens 6, which can reduce the area of ​​the light beam and enhance the intensity of the light beam. The relay lens 6 can be set at a certain tilt angle with the reflector 5, and the tilt angle is adjustable.

[0060] The relay lens 6 includes a spherical lens or an aspherical lens, and the spherical lens or the aspherical lens can be used as the relay lens 6 according to performance and cost requirements.

[0061] The prism group 7 adjusts the incident angle of the converged light beam; the converged light beam enters the prism group 7 and is incident on the DMD light modulator 8 at a suitable illumination angle to be displayed, thereby obtaining a structured light pattern. There is an angle between the prism group 7 and the DMD light modulator 8.

[0062] The prism group 7 is generally a single right-angle prism or a combination of multiple right-angle prisms based on experience or theoretical calculations.

[0063] In some embodiments, the prism group 7 uses two right-angle prisms with inclined surfaces to adjust the size and angle of the light beam incident on the DMD (image plane). The relay lens 6 and the prism group 7 can optimize the size and angle of the light beam incident on the DMD (image plane), and present the light in the effective light spot evenly, efficiently, and as clearly as possible on the DMD effective surface.

[0064] For example, in order to control the size of the incident DMD (image plane) and the angle requirement, the relay lens 6 may be tilted, or the overall tilt or decentering of the prism group 7 may be set.

[0065] The DMD light modulator 8 is a spatial micro-mirror array, and the angle between it and the prism group 7 is α, 2<α<6 degrees, in order to make the optical path structure satisfy Sham's law and realize clear oblique projection imaging on the entire projection surface.

[0066] The DMD optical modulator 8 is a reliable, efficient and high-speed MEMS spatial light modulator driven by a pure digital signal, which can be used to modulate the amplitude, direction and phase of the incident light. The DMD optical modulator 8 has a high resolution and a micro-mirror unit structure. In the digital image display, it can clearly and accurately display the details of the image, thereby reducing the distortion of the image during the imaging process.

[0067] The DMD light modulator 8 has high reflectivity and high contrast. Adding the light source 1 to the optical device can realize active projection imaging of the DMD light modulator 8 .

[0068] The projection lens 9 projects the structured light pattern actively projected and displayed on the DMD light modulator 8 onto the projection surface 10 .

[0069] In some embodiments, the projection lens 9 includes a plurality of optical lenses, which are used to project the structured light pattern on the DMD light modulator 8 onto the projection surface 10 at a certain magnification; wherein the angle between the optical axis of the projection lens 9 and the normal of the projection surface 10 is β, 20<β<35 degrees.

[0070] The projection lens includes several optical lenses, which project the structured light pattern on the DMD light modulator onto the object to be scanned at a certain magnification. The angle between the optical axis of the projection lens 9 and the normal of the projection surface 10 is β, and α and β satisfy the Schaam's law of the optical path structure.

[0071] Schaum's law states that when the extended surfaces of the image plane, lens plane, and projection plane intersect in a straight line, a completely clear image can be obtained.

[0072] The optical device provided by the utility model has high light output flux, compact layout, long service life, and can realize full-width clear tilt projection.

[0073] Example 1

[0074] Figure 3 This is a schematic diagram of an optical device provided in Example 1 of the present application. Figure 3 As shown, the optical device is used for structured light projection, including a light source 1, a three-piece collimating lens group 32, a light homogenizer 3, a negative cylindrical lens 4, a reflector 5, a relay lens 6, a prism group 7, a DMD light modulator 8, and a projection lens 9. The relay lens 6 and the prism group 7 constitute an illumination relay assembly A.

[0075] The light beam emitted by the light source 1 may be white light or other monochromatic LED. In this embodiment 1, a white light LED is taken as an example. The luminous flux of the selected light source is 1704 lumens. After passing through the collimating lens group 32, the white light divergent beam is converted into a white parallel beam.

[0076] The three-piece collimating lens group 32 is composed of three spherical lenses. Due to the complex manufacturing process of aspherical lenses, this combination is low in cost compared to the two-piece lens group, can increase the output light flux, is conducive to compact layout, and reduces the size of the optical machine.

[0077] The parallel white light beam is diffracted and homogenized by the light homogenizer 3, and the homogenized white light beam is pulled up in a single direction by the negative cylindrical lens 4, and enters the folded light path of the reflector 5. By changing the propagation path of the illumination beam by the reflector 5, the volume of the optical machine can be reduced.

[0078] The light beam after being deflected by the reflector 5 reaches the relay lens 6, and the relay lens 6 converges the light beam after being deflected by the reflector 5; the light beam converged by the relay lens 6 reaches the prism group 7, and the prism group 7 refracts the light beam converged by the relay lens 6; the light beam refracted by the prism group 7 is uniformly irradiated on the DMD light modulator 8 at a suitable angle.

[0079] In the embodiment 1 of the present application, the relay lens 6 is a spherical lens; the area of ​​the light beam can be reduced and the intensity of the light beam can be enhanced after being converged by the relay lens 6. The relay lens 6 can be set at a certain tilt angle with the reflector 5, and the tilt angle is adjustable.

[0080] In Example 1 of the present application, the prism group 7 includes a first right-angle prism 71 and a second right-angle prism 72, and the two inclined surfaces of the first right-angle prism 71 and the second right-angle prism 72 are abutted against each other; the first right-angle prism 71 adjusts the size and angle of the converged light beam incident on the DMD light modulator, and the second right-angle prism 72 adjusts the size and angle of the structured light pattern on the DMD light modulator 8, and refracts the structured light pattern into the projection lens 9.

[0081] In Example 1 of the present application, the angle between the DMD light modulator 8 and the prism group 7 is α, 2<α<6 degrees, the first right-angle prism 71 is a non-isosceles right-angle prism, the second right-angle prism 72 is an isosceles right-angle prism, and the side length of the inclined surface of the first right-angle prism 71 is smaller than that of the second right-angle prism 72.

[0082] Finally, the pattern on the DMD light modulator 8 is projected onto the projection surface 10 by the projection lens 9 .

[0083] In Example 1 of the present application, Figure 4 As shown, the angle p between the optical axis s of the projection lens 9 and the normal of the projection surface 10 is β=30°, and the corresponding angle between the DMD light modulator and the RTIR prism is α=3.32°. Finally, the equivalent image plane of the DMD light modulator 8 after reflection by the RTIR prism group 7, the plane where the normal of the optical axis of the projection lens is located, and the projection surface 10 intersect in a straight line. Its optical path structure satisfies Sham's law, realizing full-frame clear projection.

[0084] In this embodiment, α=3.32°, but it is not limited to this angle. Different angles α correspond to different projection inclination angles β.

[0085] It should be understood that the various numerical numbers involved in the embodiments of the present application are only used for the convenience of description and are not used to limit the scope of the embodiments of the present application.

Claims

1. A structured light projection optical device, characterized in that: Set up sequentially along the propagation path of the beam: A light source (1) emitting a divergent light beam; A collimating lens group (2) converts the divergent light beam into a parallel light beam; A light homogenizer (3) is used to diffract and homogenize the parallel light beam to obtain an illumination light beam; A negative cylindrical lens (4) is used to shape the light spot of the illumination light beam so that the light spot has a suitable aspect ratio; A reflector (5) reflects the shaped illumination light beam; The illumination relay assembly converges the reflected light beam, refracts it through an internal prism, and then illuminates the DMD light modulator (8) at a suitable incident angle; A DMD light modulator (8) displays and projects a structured light pattern based on the light beam at the incident angle; A projection lens (9) projects the structured light pattern onto a projection surface (10); The light source (1), the collimating lens group (2), the light homogenizer (3) and the negative cylindrical lens (4) are arranged in sequence on the same center line along the optical path; There is an angle between the normal line of the mirror surface of the reflector (5) and the center line; The equivalent image plane of the DMD light modulator (8), the plane where the normal line of the optical axis of the projection lens (9) is located and the projection surface (10) intersect in a straight line, so that the optical path structure satisfies Schaum's law.

2. The optical device according to claim 1, characterized in that The light source (1) is a monochromatic LED, including a white light LED, a red light LED, a green light LED or a blue light LED.

3. The optical device according to claim 1, characterized in that The collimating lens group (2) is a two-piece lens group or a three-piece lens group, and the collimating lens group (2) comprises a spherical lens and an aspherical lens.

4. The optical device according to claim 1, characterized in that: The light homogenizing sheet (3) comprises a diffraction-type diffuser or a diffusion-type light homogenizing device.

5. The optical device according to claim 1, characterized in that The negative cylindrical lens (4) is a column with an arc-shaped inwardly concave incident surface, and is used to pull up the light spot of the illumination light beam in one direction so that the aspect ratio of the light spot is consistent with the aspect ratio of the mirror surface of the DMD light modulator (8).

6. The optical device according to claim 1, characterized in that The lighting relay assembly comprises: A relay lens (6) for converging the reflected light beam; A prism group (7) for adjusting the incident angle of the converged light beam; The angle between the normal line of the relay lens (6) and the light beam reflected by the reflector (5) can be adjusted; There is an angle between the prism group (7) and the DMD light modulator (8).

7. The optical device according to claim 6, characterized in that The relay lens (6) comprises a spherical lens or an aspherical lens.

8. The optical device according to claim 6, characterized in that The prism group (7) comprises a first right-angle prism and a second right-angle prism, wherein two inclined surfaces of the first right-angle prism and the second right-angle prism are in contact with each other; the first right-angle prism adjusts the size and angle of the converged light beam incident on the DMD light modulator (8), and the second right-angle prism adjusts the size and angle of the structured light pattern projected by the DMD light modulator (8), and refracts the structured light pattern into the projection lens (9).

9. The optical device according to claim 8, characterized in that The angle between the DMD light modulator (8) and the prism group (7) is α, 2<α<6 degrees, the first right-angle prism is a non-isosceles right-angle prism, the second right-angle prism is an isosceles right-angle prism, and the side length of the inclined surface of the first right-angle prism is smaller than that of the second right-angle prism.

10. The optical device according to claim 1, characterized in that: The projection lens (9) comprises a plurality of different optical lenses, and projects the structured light pattern projected by the DMD light modulator (8) onto the projection surface (10) at a certain magnification, wherein an angle β between the optical axis of the projection lens (9) and the normal of the projection surface (10) is 20<β<35 degrees.

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