Novel speckle projector and optical equipment

Abstract

A novel speckle projector and optical equipment are characterized in that the novel speckle projector comprises an array laser used for projecting array laser; the micro-lens array collimator is positioned on an emergent light path of the array laser and is used for collimating the array laser; a projection lens; the focal plane of the projection lens and the micro lens array collimator are conjugated to form zero-order speckles. According to the utility model, the problem of insufficient uniformity of projected speckles in the existing speckle projection scheme can be solved, and uniform speckle projection is realized.

Description

Technical Field

[0001] This utility model relates to the field of optical technology, specifically to a novel speckle projector and optical device. Background Technology

[0002] In many fields that rely on optical imaging and measurement technologies, such as 3D vision sensing, lidar, and biomedical imaging, there is a strong demand for high-quality speckle projection. Traditional speckle projection schemes have many shortcomings in terms of speckle quality, beam collimation, and overall stability.

[0003] Regarding speckle quality: Early speckle projectors generated speckle patterns with poor uniformity and uneven intensity distribution, which led to errors in speckle-based measurements and imaging, affecting the accuracy and reliability of the data. For example, in 3D visual perception, uneven speckle can cause deviations in depth information acquisition, reducing the accuracy of the reconstructed model.

[0004] Beam collimation effect: In previous optical systems, the collimation of the laser beam was not ideal, resulting in severe divergence and significant energy loss during propagation. This not only limited the projection distance but also made the speckle blurry at long distances, failing to meet the requirements of applications such as lidar that require long-distance, high-precision speckle projection.

[0005] Overall stability: Traditional methods are susceptible to environmental factors (such as temperature and vibration), resulting in poor stability of speckle projection. In biomedical imaging, even minute speckle fluctuations can interfere with the observation and analysis of the fine structures of biological tissues.

[0006] Against this backdrop, and to meet the ever-increasing technical requirements of various fields, it is essential to develop a new type of speckle projector. By optimizing the design and coordination of key components such as array lasers and microlens array collimators, the shortcomings of traditional solutions can be effectively addressed, improving speckle quality, beam collimation, and overall stability, thus providing strong support for the development of related fields.

[0007] The above background information is provided only to aid in understanding the inventive concept and technical solution of this utility model. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed on the filing date of this patent application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Utility Model Content

[0008] To address this issue, this invention proposes a large speckle projection system that overcomes the problem of insufficient uniformity of projected speckle in existing speckle projection schemes, thereby achieving uniform speckle projection.

[0009] In a first aspect, this utility model provides a novel speckle projector, characterized in that it comprises:

[0010] Array laser, used to project array laser beams;

[0011] A microlens array collimator is located in the output optical path of the array laser and is used to collimate the array laser.

[0012] A projection lens; the focal plane of the projection lens is conjugate with the collimator of the microlens array to form zero-order speckle.

[0013] Optionally, the novel speckle projector is characterized by further comprising:

[0014] A 45° reflecting prism is located between the microlens array collimator and the projection lens to change the optical path direction of the array laser.

[0015] Optionally, the novel speckle projector is characterized in that the 45° reflecting prism is either externally reflecting or internally totally reflecting.

[0016] Optionally, the novel speckle projector is characterized in that the array laser includes multiple emitting units, each of which can be individually controlled to change the laser intensity.

[0017] Optionally, the novel speckle projector is characterized in that the microlens array collimator includes a plurality of collimating elements, each of the collimating elements collimating one or more of the transmitting units.

[0018] Optionally, the novel speckle projector is characterized in that at least two of the collimating elements are oriented differently.

[0019] Optionally, the novel speckle projector is characterized in that the collimating element corresponds one-to-one with the transmitting unit.

[0020] Optionally, the novel speckle projector is characterized by further comprising:

[0021] A DOE diffraction device is located on the light-emitting surface of the projection lens to replicate the zero-order speckle.

[0022] Optionally, the novel speckle projector is characterized in that the magnification at the center of the DOE diffraction device is greater than the magnification at the edge.

[0023] Secondly, this utility model provides an optical device, characterized in that it includes the novel speckle projector described in any one of the above claims.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The array laser used in this invention has multiple laser emitting units precisely arranged inside, and the output array laser intensity is ensured to be uniform and stable by precisely controlling the driving current. This provides a stable and reliable foundation for the entire speckle projection process, greatly reducing speckle fluctuations caused by laser source instability, and ensuring consistency in measurement and imaging in various application scenarios.

[0026] The microlens array collimator of this invention is composed of high-precision microlenses, enabling independent and precise collimation of the laser beam corresponding to each laser emitting unit. Compared with traditional collimation methods, it greatly improves the directionality of the laser beam, reduces beam divergence loss, and allows the laser beam to maintain a high energy density during propagation, providing a strong guarantee for the formation of high-quality zero-order speckle on the focal plane of the projection lens.

[0027] In this invention, the focal plane of the projection lens is conjugate to the collimator of the microlens array, a conjugate relationship carefully designed and calculated. This ensures that the collimated laser beam is accurately focused on the focal plane of the projection lens, forming a clear, stable, and intensity-distributed zero-order speckle pattern. This precise focusing and speckle formation method effectively avoids blurring and distortion of the speckle, improving its quality and usability.

[0028] This invention, through the coordinated operation of its various components, from stable laser source emission to precise collimation and focusing to form zero-order speckle, effectively solves the shortcomings of traditional speckle projectors in terms of speckle quality, beam collimation effect, and overall stability. It significantly improves the quality and reliability of speckle projection and provides strong technical support for the technological development in related fields. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort. Other features, objects, and advantages of this utility model will become more apparent by reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0030] Figure 1 This is a schematic diagram of the optical path of a novel speckle projector according to an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the optical path of another novel speckle projector in an embodiment of this utility model;

[0032] Figure 3 This is a schematic diagram of the optical path of another novel speckle projector in an embodiment of this utility model;

[0033] Figure 4 This is a schematic diagram of the structure of a microlens array collimator in an embodiment of the present invention;

[0034] Figure 5 This is a schematic diagram of the optical path of another novel speckle projector in an embodiment of this utility model;

[0035] Figure 6 This is a schematic diagram of the projection effect of a DOE diffraction device in an embodiment of this utility model.

[0036] 1-Array laser;

[0037] 2-Microlens array collimator;

[0038] 3-45° reflecting prism;

[0039] 4-Projection lens;

[0040] 5-DOE diffraction device; Detailed Implementation

[0041] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0042] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the utility model described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0043] This utility model provides a novel speckle projector, which aims to solve the problems existing in the prior art.

[0044] The technical solutions of this utility model and this application solve the above-mentioned technical problems in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this utility model will now be described with reference to the accompanying drawings.

[0045] This invention first uses an array laser to emit an array of laser beams. A microlens array collimator then shapes the beams into a collimated and uniform rectangular light field. This field is then projected and cross-focused to form a zero-order speckle pattern. Finally, a DOE diffractometer replicates the zero-order speckle pattern, thus multiplying the number of speckles and expanding the projection angle. Compared to existing technologies, this invention can project tens of times more speckles, and this higher speckle count provides the hardware necessary for more accurate 3D visual modeling.

[0046] Figure 1 This is a schematic diagram of the optical path of a novel speckle projector according to an embodiment of this utility model. Figure 1 As shown, a novel speckle projector in this embodiment of the present invention includes:

[0047] Array laser 1, used to project array laser.

[0048] Specifically, the array laser, as the light source component of the speckle projector, emits an array of laser beams. These laser beams are arranged in a specific array pattern, providing the initial light basis for subsequent speckle pattern generation. By precisely controlling the position and intensity of each emitting unit in the array laser, a stable and adjustable light input can be provided for subsequent optical processing. The array laser is typically rectangular in shape, resulting in a rectangular distribution of the emitted laser light.

[0049] The microlens array collimator 2 is located in the output optical path of the array laser and is used to collimate the array laser.

[0050] Specifically, a microlens array collimator is placed in the output optical path of the array laser, and its core function is to collimate the array laser emitted from the array laser. Since the light emitted by the laser may initially have a certain divergence angle, the collimator, through a series of microlenses, adjusts these divergent rays into parallel rays. This process improves the directionality and consistency of the light, making subsequent optical processing more precise and laying the foundation for the formation of high-quality zero-order speckle. It should be noted that in this embodiment, each beam is adjusted to be a parallel beam, rather than adjusting different beams together to be parallel beams. In this embodiment, the multiple beams after passing through the microlens array collimator may not be parallel; they may have a certain angle between them, and the overall beams may exhibit a certain divergence angle.

[0051] Projection lens 4; the focal plane of the projection lens is conjugate with the collimator of the microlens array to form zero-order speckle.

[0052] Specifically, the focal plane of the projection lens is conjugate to the collimator of the microlens array. Parallel light rays, processed by the collimator, enter the projection lens. The projection lens focuses and images the light rays on the focal plane, ultimately forming zero-order speckle at a specific location. This zero-order speckle is the foundation for the entire speckle projector to generate complex speckle patterns, and its quality and characteristics directly affect the effect of the subsequently reproduced speckle. The optical performance of the projection lens, such as focal length and aberrations, plays a crucial role in the sharpness and uniformity of the zero-order speckle.

[0053] The larger the emission angle of the array laser, the greater the distance between the array laser and the microlens array collimator. There is a correlation between the emission angle of the array laser and the distance between the array laser and the microlens array collimator. When the emission angle of the array laser is larger, in order to ensure that the collimating element can effectively capture and collimate the light, the distance between the array laser and the microlens array collimator needs to be increased. This is because a larger emission angle means a wider divergence range of the light during propagation, and a greater distance allows the collimator sufficient space to adjust the convergence or divergence of the light to achieve the preset output.

[0054] In some embodiments, the array laser includes multiple emitting units, each of which can be individually controlled to change the laser intensity. As the light source component of the speckle projector, the array laser consists of multiple emitting units arranged in a specific array, each of which can be individually controlled. This feature makes it possible to change the intensity of the emitted laser by precisely adjusting the operating state of each emitting unit. For example, in different application scenarios, the laser intensity of each emitting unit can be flexibly controlled according to actual needs, thereby providing a stable and finely adjustable light input for subsequent speckle pattern generation. This individually controllable characteristic greatly enhances the flexibility and adaptability of the light source, enabling it to meet diverse optical processing requirements.

[0055] Figure 2 This is a schematic diagram of the optical path of another novel speckle projector in an embodiment of this utility model. Figure 2 As shown, compared to the aforementioned embodiments, another novel speckle projector in this embodiment of the present invention further includes:

[0056] A 45° reflecting prism 3 is located between the microlens array collimator and the projection lens to change the optical path direction of the array laser.

[0057] Specifically, the 45° reflecting prism is located between the microlens array collimator and the projection lens, and its main function is to change the optical path direction of the array laser. When parallel light rays processed by the collimator enter the 45° reflecting prism, according to the law of reflection, the light rays will change their propagation direction at a 90° angle. This design makes the optical path layout more flexible, and in practical applications, it can meet different spatial constraints and optical system layout requirements, providing more possibilities for system integration and application. By reasonably setting the position and angle of the 45° reflecting prism, the direction of the light rays can be precisely controlled to ensure that they accurately enter the projection lens for subsequent processing.

[0058] A high-reflectivity film is deposited on the reflective surface. The appropriate coating material and thickness are selected based on the wavelength of the light source to achieve a high level of reflectivity. For example, for the visible light band, a multilayer dielectric film can be used to achieve a reflectivity of over 99%. Simultaneously, an anti-reflective film can be deposited on other non-reflective surfaces to reduce interference from stray light.

[0059] like Figure 2 As shown, the 45° reflecting prism is an external reflection. When light from a medium outside the prism (such as air) enters the surface of the 45° reflecting prism at a suitable angle, the light is reflected at the prism surface. In this case, special treatment is needed on the prism surface to improve reflection efficiency and reduce light loss. For example, by coating the prism surface with a high-reflectivity metal film or a multilayer dielectric film, the light can be reflected efficiently, thus changing its propagation direction by 90°. This external reflection method is advantageous in scenarios where the intensity of reflected light is required and the complexity of the prism's internal structure is relatively low.

[0060] like Figure 3 As shown, the 45° reflecting prism exhibits total internal reflection. When light travels from a high-refractive-index medium inside the prism to the interface with a low-refractive-index medium (such as air), total internal reflection occurs if the angle of incidence is greater than the critical angle. The design of the 45° reflecting prism ensures that parallel light rays, after being collimated, propagate within the prism and are incident at a suitable angle onto a specific interface, thus achieving total internal reflection. The advantages of total internal reflection include minimal light loss during reflection, maintaining high light intensity and beam quality. Furthermore, since no additional coatings or complex treatments are required on the prism surface, the manufacturing process is relatively simplified.

[0061] Figure 4This is a schematic diagram of a microlens array collimator according to an embodiment of the present invention. The microlens array collimator includes multiple collimating elements, each of which collimates one or more of the emitting units. Each collimating element is responsible for collimating the light emitted by one or more emitting units. Since the light emitted by the laser's emitting units may initially have a certain divergence angle, the collimating element, through its own microlens structure, adjusts these divergent light rays into parallel light rays. For example, for emitting units at different positions and angles, the corresponding collimating element will precisely adjust the light convergence or divergence according to its light characteristics to achieve parallel output. The orientations of different collimating elements can be different, and at least two of the collimating elements have different orientations. When a collimating element corresponds one-to-one with an emitting unit, each collimating element adjusts the beam emitted by one emitting unit, thereby achieving fine adjustment of the beam and precisely controlling the divergence angle and direction of the beam after passing through the microlens array collimator. Through the coordinated work of multiple collimating elements, the directionality and consistency of the entire array laser are significantly improved, making subsequent optical processing more precise and laying a solid foundation for the formation of high-quality zero-order speckle.

[0062] Figure 5 This is a schematic diagram of the optical path of another novel speckle projector in an embodiment of this utility model. Figure 5 As shown, compared to the aforementioned embodiments, another novel speckle projector in this embodiment of the present invention further includes:

[0063] DOE diffraction device 5 is located on the light-emitting surface of the projection lens to replicate the zero-order speckle.

[0064] Specifically, the DOE diffractometer is located on the light-emitting surface of the projection lens, and its main function is to replicate the already formed zero-order speckle pattern. Utilizing the principle of light diffraction, the DOE diffractometer uses a carefully designed diffraction pattern to diffract the incident zero-order speckle light according to a specific rule, thereby generating multiple speckle patterns in space that are similar to the zero-order speckle. These replicated speckles play an important role in various applications, such as 3D imaging and surface feature measurement. By rationally designing the diffraction structure of the DOE diffractometer, parameters such as the number, distribution, and intensity of the replicated speckles can be flexibly controlled.

[0065] In this embodiment, the DOE diffraction device is located on the light-emitting surface of the projection lens. Utilizing advanced diffraction optics principles, it can replicate and expand zero-order speckle according to predetermined rules. This means that the number and distribution of speckle can be flexibly adjusted according to the needs of different application scenarios, greatly expanding the application range of speckle projectors. Whether in 3D vision perception, LiDAR, or biomedical imaging, it can better meet diverse needs.

[0066] Figure 6 This is a schematic diagram illustrating the projection effect of a DOE diffraction device according to an embodiment of this utility model. Figure 6 In the diagram, D represents the actual projection range of the pattern projected by the projection lens, and E, F, G, H, J, K, L, and M represent the images reproduced by DOE diffraction. Through diffraction optics design, diffraction pattern ranges in different directions can be seamlessly stitched together. The magnification at the center of the DOE diffracting device is greater than that at the edges. DOE diffracting devices utilize the principle of light diffraction, where the magnification at the center is greater than that at the edges. This means that when replicating zero-order speckle, the speckle in the central region will be magnified more significantly in terms of size and other aspects. When the light from the zero-order speckle is incident on the DOE diffracting device, the speckle pattern formed after diffraction in the central part will have a greater spatial expansion. The light at the edges, due to its relatively smaller magnification, will have a limited speckle expansion. Through carefully designed diffraction patterns, the incident zero-order speckle light is diffracted according to specific rules, thereby generating multiple speckle patterns similar to the zero-order speckle in space. This characteristic of different magnification between the center and the edge has significant practical value in applications where high precision and size of the speckle pattern in the central region are required, such as specific 3D imaging and high-precision measurement of surface features at the center of an object. By rationally designing the diffraction structure of the DOE diffractometer, parameters such as the number, distribution, and intensity of the replicated speckle pattern can be flexibly controlled.

[0067] This utility model also provides an optical device comprising the novel speckle projector described in any of the foregoing claims. This optical device can be of various types; a depth camera will be used as an example for illustration below. It should be noted that this embodiment is merely illustrative to provide those skilled in the art with a clearer understanding of the optical device and should not be construed as limiting the scope of protection of this utility model.

[0068] Depth cameras, as devices capable of acquiring depth information of objects in a scene, have wide applications in many fields, such as robot navigation, virtual reality, and security monitoring. The depth camera introduced in this article is unique in that it incorporates a novel speckle projector, which significantly enhances the camera's performance and functionality.

[0069] The novel speckle projector is one of the key components of a depth camera. Its specific workflow is as follows:

[0070] Array laser: As the light source for the speckle projector, the array laser consists of multiple individually controllable emitting units. When the depth camera is operating, these emitting units can precisely adjust the intensity of their emitted lasers according to different scene requirements. For example, in low-light environments, the laser intensity of the emitting units can be increased to ensure the projected speckle pattern is clearly discernible. Furthermore, the emission angle of the array laser is related to the distance between the array laser and the microlens array collimator. A larger emission angle requires increasing the distance between them to ensure collimation, thus allowing sufficient space for the collimating elements to adjust the light into parallel rays during propagation.

[0071] Microlens array collimator: Located in the output light path of the array laser, it consists of multiple collimating elements. Each collimating element is responsible for collimating the light emitted from one or more emitting units. Since the light emitted from the laser emitting units may initially have a divergence angle, the collimating element, through its own microlens structure, adjusts these divergent rays into parallel rays, providing a stable and well-directional beam for subsequent optical processing. This is crucial for forming high-quality zero-order speckle.

[0072] The 45° reflecting prism, positioned between the microlens array collimator and the projection lens, primarily functions to alter the optical path direction of the array laser. It can achieve either external reflection or total internal reflection. For external reflection, special treatment is required on the prism surface, such as coating it with a high-reflectivity metal film or multilayer dielectric film, to improve reflection efficiency. Total internal reflection utilizes the principle that when light travels from a high-refractive-index medium to a low-refractive-index medium interface inside the prism, the angle of incidence is greater than the critical angle. This flexible reflection method allows the optical path layout to better adapt to the internal spatial structure of the depth camera, meeting diverse design requirements.

[0073] Projection lens: Its focal plane is conjugate to the microlens array collimator. Parallel light rays, after being altered by a 45° reflecting prism, enter the projection lens. The projection lens focuses and images the light rays on the focal plane, ultimately forming zero-order speckle at a specific location. This zero-order speckle is the basis for subsequently generating complex speckle patterns, and its quality directly affects the accuracy of the depth camera in acquiring depth information of objects.

[0074] DOE (Diffraction Element): Located on the light-emitting surface of the projection lens, its main function is to reproduce zero-order speckle. Its unique feature is that the magnification at the center is greater than that at the edges. This makes the speckle in the central region more noticeably magnified in terms of size and other aspects when reproducing zero-order speckle. In depth cameras, this characteristic is significant for improving the measurement accuracy of depth information in the central region of objects, for example, providing more precise details when performing depth imaging of important areas such as human faces.

[0075] A depth camera actively projects a speckle pattern onto a target object and then uses its lens to capture the reflected light carrying the speckle information. Due to variations in distance and shape on the object's surface, the reflected speckle pattern is distorted accordingly. The image sensor in the depth camera captures these distorted speckle patterns and converts them into electrical signals. Then, built-in algorithms analyze and process these electrical signals, transforming the distortion information of the speckle pattern into depth information for various points on the object's surface. Finally, based on this depth information, a 3D model or depth image of the target object is generated.

[0076] The advantages of depth cameras are as follows:

[0077] High-precision depth measurement: The new speckle projector can project high-quality and customizable speckle patterns. Its unique optical structure and parameter settings, especially the different magnifications of the center and edge of the DOE diffraction device, enable the depth camera to achieve higher accuracy when measuring the depth of objects. In particular, it can clearly distinguish the fine structure and depth changes of objects in the central region.

[0078] Adaptable to complex environments: The laser array's emitting units can be individually controlled for laser intensity, enabling the depth camera to function normally under various lighting conditions. Whether in brightly lit outdoor scenes or dimly lit indoor environments, adjusting the intensity of the emitting units ensures that the projected speckle pattern is clearly visible, thereby accurately acquiring the object's depth information.

[0079] Flexible optical path design: The 45° reflecting prism's ability to achieve external or total internal reflection, along with its placement within the optical path, allows for greater flexibility in the internal optical path design of depth cameras. This helps optimize the optical system's structure within limited space, improving the camera's integration and stability, while also reducing optical losses and interference that may result from improper optical path design.

[0080] Broad Application Prospects: Based on the aforementioned advantages, this depth camera, incorporating a novel speckle projector, has broad application prospects in multiple fields. In robotics, it can be used for robot navigation and obstacle avoidance, enabling robots to perceive their surroundings more accurately; in virtual reality and augmented reality, it can provide users with a more realistic and immersive experience, accurately capturing user movements and location information; in security monitoring, the depth camera can achieve three-dimensional monitoring of target objects, improving the accuracy and reliability of monitoring.

[0081] The various embodiments described in this specification are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The above description of the disclosed embodiments enables those skilled in the art to implement or use this invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this invention. Therefore, this invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0082] The specific embodiments of this utility model have been described above. It should be understood that this utility model is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the substantive content of this utility model.

Claims

1. A novel speckle projector, characterized in that, include: Array laser, used to project array laser beams; A microlens array collimator is located in the output optical path of the array laser and is used to collimate the array laser. Projection lens; The focal plane of the projection lens is conjugate with the collimator of the microlens array to form zero-order speckle.

2. The novel speckle projector according to claim 1, characterized in that, Also includes: A 45° reflecting prism is located between the microlens array collimator and the projection lens to change the optical path direction of the array laser.

3. A novel speckle projector according to claim 2, characterized in that, The 45° reflecting prism is either externally reflecting or internally reflecting.

4. A novel speckle projector according to claim 1, characterized in that, The array laser includes multiple emitting units, each of which can be individually controlled to change the laser intensity.

5. A novel speckle projector according to claim 4, characterized in that, The microlens array collimator includes multiple collimating elements, each of which collimates one or more of the transmitting units.

6. A novel speckle projector according to claim 5, characterized in that, At least two of the collimating elements are oriented differently.

7. A novel speckle projector according to claim 5, characterized in that, The collimating element corresponds one-to-one with the transmitting unit.

8. A novel speckle projector according to claim 1, characterized in that, Also includes: A DOE diffraction device is located on the light-emitting surface of the projection lens to replicate the zero-order speckle.

9. A novel speckle projector according to claim 8, characterized in that, The magnification at the center of the DOE diffraction device is greater than that at the edge.

10. An optical device, characterized in that, Including the novel speckle projector as described in any one of claims 1-9.

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