CN211878344U - Laser emission module and 3D imaging device - Google Patents

Abstract

The utility model provides a laser emission module and 3D imaging device relates to optical device technical field, and the light source subassembly can the emergent beam, and the beam of emergent goes out parallel light beam after collimating through the collimating mirror, and this parallel light beam is behind the diffractive optical element, is duplicated and splices and forms many parallel light, and many parallel light emergent extremely reduce behind the camera lens, is reduced the back with preset multiplying power and throws in the target space and generate speckle point pattern to reach the purpose of reducing the angle of view of laser emission module, improve the density of scattered spot in the unit area, simultaneously, utilize to reduce the camera lens and can also reduce the facula diameter of scattered spot, thereby reach the purpose that improves the energy density of the facula of every scattered spot. And then make the texture in target space more clear, the contrast is higher, and the laser emission module of being convenient for can acquire more accurate degree of depth measurement information when remote application, lays a good foundation for its extensive application.

Description

Laser emission module and 3D imaging device

Technical Field

The utility model relates to an optical device technical field particularly, relates to a laser emission module and 3D imaging device.

Background

The 2D imaging device can acquire 2D plane information of an object, but the conventional 2D imaging device has slowly failed to satisfy daily needs of people due to rapid improvement of living standard of people. With the intensive research of science and technology, the 3D imaging device can further acquire the depth information of an object on the basis of 2D imaging, so that a three-dimensional 3D model is constructed, and the three-dimensional 3D model is widely applied to the fields of industrial measurement, biological recognition, AR, VR and the like.

In the 3D imaging device, the core component is a laser emission module which is mainly used for projecting speckle point patterns into a target space and realizing the measurement of depth information by acquiring the speckle point patterns in the target space through a receiving camera. However, in practical applications, when the object is far away from the laser emitting module, the density of scattered spots is small, the diameter of the spot is large, the energy density is low, the texture of the target space is unclear, the contrast is not obvious, and effective depth measurement is difficult to form.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to the not enough among the above-mentioned prior art, provide a laser emission module and 3D imaging device to solve current 3D imaging device and be difficult to acquire the problem of accurate degree of depth measurement information when remote the throwing.

In order to achieve the above object, the embodiment of the present invention adopts the following technical solutions:

the utility model discloses an aspect provides a laser emission module, include: the device comprises a light source component, a collimating mirror, a diffraction optical element and a reduction lens; the light beam emitted from the light source component enters the diffractive optical element after passing through the collimating mirror, and the light beam emitted from the diffractive optical element reduces the field angle of the light beam emitted from the diffractive optical element by a preset reduction magnification through the reduction lens to form a speckle point pattern in a target space.

Optionally, the zoom-out lens includes a first positive lens and a negative lens; the light beams emitted from the diffractive optical element are converged by the first positive lens and then are subjected to beam expanding projection by the negative lens, wherein the distance between the negative lens and the first positive lens is smaller than the focal length of the first positive lens.

Optionally, the distance between the negative lens and the first positive lens is equal to the absolute value of the sum of the focal length of the first positive lens and the focal length of the negative lens.

Optionally, the preset reduction magnification is equal to a ratio of a focal length of the negative lens to a focal length of the first positive lens.

Optionally, the first positive lens is a biconvex lens, and the negative lens is a plano-concave lens.

Optionally, the zoom-out lens includes a second positive lens and a third positive lens; and the light beams emitted from the diffractive optical element are converged by the second positive lens and the third positive lens in sequence and then projected, wherein the distance from the third positive lens to the second positive lens is greater than the focal length of the second positive lens.

Optionally, the distance between the second positive lens and the third positive lens is equal to the sum of the focal length of the second positive lens and the focal length of the third positive lens.

Optionally, the light source module includes a plurality of vertical cavity surface emitting lasers arranged in a matrix.

Optionally, the collimating mirror comprises a micro-lens array; the plurality of microlens units in the microlens array are arranged in one-to-one correspondence with the plurality of vertical cavity surface emitting lasers.

The utility model discloses on the other hand of embodiment provides a 3D imaging device, including receiving module, processing module and any kind of above-mentioned laser emission module, receiving module and laser emission module set up in same reference surface, receiving module is used for gathering the speckle point pattern that laser emission module throwed, and processing module is connected with receiving module electricity for calculate according to speckle point pattern and draw the depth image.

The beneficial effects of the utility model include:

the utility model provides a laser emission module, include: light source subassembly, collimating mirror, diffraction optical element and reducing lens. The light source component can emit light beams, the emitted light beams are collimated by the collimating lens and then emit parallel light beams, the parallel light beams are copied and spliced to form a plurality of parallel light beams after passing through the diffraction optical element, the plurality of parallel light beams are emitted to the reduction lens and then reduced by a preset multiplying power to be projected into a target space to generate a speckle point pattern, so that the aim of reducing the field angle of the laser emission module is fulfilled, the density of scattered spots in a unit area is improved, meanwhile, the field angle is reduced, the diameter of light spots of the scattered spots is also reduced, and the aim of improving the energy density of the light spots of each scattered spot is fulfilled. And then make the texture in target space more clear, the contrast is higher, and the laser emission module of being convenient for can acquire more accurate degree of depth measurement information when remote application, lays a good foundation for its extensive application.

The utility model also provides a 3D image device is applied to foretell laser emission module in the 3D formation of image, still including receiving module and processing module simultaneously. With receiving module and laser emission module setting at same reference surface, because the light beam that the laser emission module sent has certain angle of vision, receiving module is when receiving, also receives the pattern to certain angle within range, consequently, the target space should just be located receiving module and the mutual overlapping within range of laser emission module to be convenient for accurate discernment and receipt. After the laser emission module projects the speckle point pattern into the target space, because the speckle point pattern is displayed in the target space after being reduced by the reduction lens with the preset reduction ratio, the area of the whole speckle point pattern is reduced to increase the speckle point density in the unit area, thereby reducing the diameter of the light beam of each scattered spot, improving the energy density of each scattered spot, thereby effectively improving the texture definition, the contrast and the like of the speckle point pattern projected by the laser emission module in the target space when the 3D imaging device is applied in a long distance, therefore, the receiving module collects clearer images, the processing module can calculate and analyze the depth information of the object in the target space more accurately according to the clear speckle point pattern with high contrast, and the depth information measurement with higher precision is realized.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a schematic structural diagram of a laser emitting module according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a zoom lens of a laser transmitter module according to an embodiment of the present invention;

fig. 3 is a second schematic structural view of a zoom lens of a laser transmitter module according to an embodiment of the present invention;

fig. 4 is a third schematic structural view of a zoom lens of a laser transmitter module according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of a 3D imaging apparatus according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of a light source assembly of a laser emission module according to an embodiment of the present invention;

fig. 7 is a schematic view of a speckle dot pattern formed in a target space by the laser emission module according to an embodiment of the present invention;

fig. 8 is a schematic diagram of a speckle dot pattern formed in a target space by a conventional laser emission module.

Icon: 100-a laser emission module; 110-a light source assembly; 120-a collimating mirror; 130-a diffractive optical element; 140-zoom out lens; 141-a first positive lens; 142-a negative lens; 143-a second positive lens; 144-third positive lens; 210-a first light beam; 220-a second light beam; 230-a third beam; 250-existing speckle dot pattern; 260-speckle dot pattern; 300-a processing module; 400-a receiving module; 500-object to be measured.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the accompanying drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. It should be noted that, in the case of no conflict, various features in the embodiments of the present invention may be combined with each other, and the combined embodiments are still within the scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate the position or positional relationship based on the position or positional relationship shown in the drawings, or the position or positional relationship which is usually placed when the product of the present invention is used, and are only for convenience of description and simplification of the description, but do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

Furthermore, the terms "horizontal", "vertical" and the like do not imply that the components are required to be absolutely horizontal or pendant, but rather may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In 2D imaging, a planar sensor receives visible light reflected or emitted by a subject to be photographed, thereby forming a two-dimensional image, which is a planar image containing no depth information. Two dimensions are four directions of left and right, up and down, without front and back. The content on a piece of paper can be seen as two-dimensional, i.e. it can represent an area, but not a volume. Since the real world is a three-dimensional world, 2D imaging has a condition of object feature missing (object depth information cannot be obtained), which means that 2D imaging does not support measurement of three-dimensional information of an object, such as AI functions of 3D face recognition, three-dimensional modeling, and the like, and 2D imaging techniques cannot support the measurement. Therefore, in order to meet more and more demands, the 3D imaging technology has been widely researched and broken through, and mainly obtains depth information of an object to be measured on the basis of 2D imaging, so as to combine with a two-dimensional image to establish a three-dimensional model of the object.

The 3D sensor generally consists of a plurality of cameras and a depth sensor, and the 3D sensor can acquire depth information of an object by projecting an active light source of a special waveband and calculating a light emission and reflection time difference. The 3D sensing technology realizes the acquisition of real-time three-dimensional information of the object and provides key features for later image analysis. The intelligent device can restore the real three-dimensional world according to the 3D sensing and realize subsequent intelligent interaction. Currently, there are two main types of 3D imaging devices that are most widely used: structured light and TOF (time of flight) depth cameras.

The most important part in the depth camera is the laser emission module, which mainly functions to project a speckle dot pattern (i.e. a pattern with depth information is composed of a large number of scattered spots, which can also be called as light spots, stripes, etc.) into a target space by utilizing a self-luminous form. However, in practical use, when the object is far from the laser emission module, the area of the speckle dot pattern formed by projecting the light beam emitted by the laser emission module in the target space (i.e. the position of the object in the space) is large, so that the number of the speckle dots in a unit area is relatively small, i.e. the density of the scattered dots is relatively small, meanwhile, the diameter of the light spot of the scattered dot is relatively large, the energy density carried by the light spot is relatively low, the texture of the speckle dot pattern presented in the target space is directly unclear, the contrast is relatively low, the edge is dispersed, and when subsequent processing is caused, the depth information of the object to be detected is difficult to be accurately acquired according to the presented speckle dot pattern, and the three-dimensional model of the object cannot be accurately constructed. This problem directly results in 3D imaging devices that are difficult to use at long distances. Based on this basis, this application provides a laser emission module 100 and 3D imaging device, reduces the diameter of the facula of the speckle point that laser emission module 100 presented from the angle of reducing the angle of view of laser emission module 100, improves the definition, the contrast of the speckle point pattern 260 that laser emission module 100 presented in the target space.

The embodiment of the utility model provides an aspect, refer to fig. 1, provide a laser emission module 100, include: a light source module 110, a collimating mirror 120, a diffractive optical element 130, and a reduction lens 140; the light beam emitted from the light source assembly 110 enters the diffractive optical element 130 through the collimating mirror 120, and the light beam emitted from the diffractive optical element 130 reduces the field angle of the light beam emitted from the diffractive optical element 130 by a predetermined reduction magnification through the reduction lens 140 to form the speckle dot pattern 260 in the target space.

Illustratively, as shown in fig. 1, the light source assembly 110, the collimator lens 120, the diffractive optical element 130, and the reduction lens 140 are sequentially disposed. The light source assembly 110 can emit a light beam to the collimating mirror 120, and the light beam directly emitted from the light source assembly 110 generally has a certain divergence angle. When the light beam passes through the collimating mirror 120, the light beam can be collimated by using the converging effect thereof, so that the light beam with a certain divergence angle passes through the collimating mirror 120 and then exits in a parallel light beam manner (the parallel light beam here can be not only completely parallel light beams, but also approximately parallel light beams, that is, the radius of the light beam is close to a constant within a required transmission distance), the parallel light beam collimated by the collimating mirror 120 enters the diffractive optical element 130, and when the light beam passes through the diffractive optical element 130, the parallel light beam is replicated into a plurality of beams by using the replication and splicing characteristics of the diffractive optical element 130 itself, and the plurality of parallel light beams exit at a specific angle by means of diffraction.

On one hand: when a plurality of parallel light beams exit from the diffractive optical element 130 and then enter the reduction lens 140, the field angle of the light beams exiting from the diffractive optical element 130 (the field range of the optical instrument is determined by the size of the field angle) is reduced by the reduction lens 140 at a predetermined reduction magnification, so that the speckle dot pattern 260 is finally formed in the target space. It should be noted here that, according to the characteristics of light propagation and the function of the diffractive optical element 130, for a given laser emission module, the area of the speckle dot pattern projected and formed at a short distance is smaller than that of the speckle dot pattern projected and formed at a long distance, but as the projection distance increases, the area of the speckle dot pattern increases, the number of scattered spots in a unit area gradually decreases, the diameter of a single scattered spot becomes larger, and the energy density becomes lower, which is also an important factor causing poor long-distance imaging.

Therefore, in the laser emission module 100 of the present application, the reduction lens 140 is added behind the diffractive optical element 130, and with reference to fig. 7 and 8, the area of the speckle dot pattern 260 projected in the target space at a long distance is smaller than the area of the conventional speckle dot pattern 250 projected in the same target space without adding the reduction lens 140, but the number of the light spots forming the speckle dot pattern 260 is not reduced, so that the number of the scattered light spots in a unit area can be effectively increased. It should be noted that, as shown in fig. 5, it should be understood by those skilled in the art that when the preset reduction magnification is set, it is necessary to ensure that the area of the speckle dot pattern 260 projected and formed by the laser emitting module 100 in the target space can completely cover the object 500 to be measured, that is, when the preset reduction magnification value is set, those skilled in the art may flexibly set the value according to the size of the object to be measured and the projected distance.

On the other hand: when the field angle of the plurality of parallel light beams is reduced by the reducing lens 140 at a predetermined reduction ratio, the diameter of each parallel light beam is also reduced at the predetermined reduction ratio, that is, the diameter of each parallel light beam after exiting from the reducing lens 140 is smaller than the diameter of each parallel light beam before entering the reducing lens 140. From the viewpoint of the diameter of the light spot, the diameter of the light spot formed in the target space by each parallel light beam emitted after entering the reduction lens 140 is smaller than the diameter of the light spot formed in the target space by each parallel light beam before entering the reduction lens 140, and the light spot formed by each parallel light beam is regarded as a circle approximately, that is, the area of the circle formed by the former is smaller than that of the circle formed by the latter.

In summary, the laser emitting module 100 in the present application reduces the angle of view of the light beam emitted from the diffractive optical element 130 to reduce the diameter of the light spot, so as to effectively improve the quality of the speckle dot pattern 260 projected in the long-distance target space, i.e. to form the high-definition and high-contrast speckle dot pattern 260. The method provides a good basis for the subsequent analysis and calculation of the receiving module 400 and the processing module 300, so that the depth information in the target space can be accurately obtained from the high-quality speckle dot pattern 260, and the high-precision depth information measurement in the three-dimensional imaging mode is realized.

First, the number of the light source assemblies 110 in the present application may be one, may also be multiple, and may also be a point light source, a line light source, a surface light source, or the like. When there are a plurality of them, they may be arranged in a matrix as shown in fig. 6 in the following embodiments, or may be arranged randomly, and this embodiment does not specifically limit them.

Second, the collimating lens 120 in this application may be a plano-convex lens, a biconvex lens, or another combined lens capable of transforming the light of each point into a parallel light beam, and the type of the lens is not particularly limited in this application.

Third, the Diffractive Optical element 130 (DOE) is a phase modulation device, which mainly implements phase modulation by adjusting the height of the structure therein. And the step height is obtained by calculating the design according to the target light field by a computer and then is prepared by the photoetching technology. The diffractive optical element 130 can be used to perform holographic imaging, focusing, and beam splitting functions.

Fourth, the conventional speckle pattern 250 and the speckle pattern 260 are patterns formed by a plurality of scattered spots formed by a plurality of light beams. The target space refers to a spatial position where an object to be measured is located, and includes not only two-dimensional information but also depth information, i.e., information of a third dimension. In fig. 7, the speckle dot pattern 260 of the laser emission module 100 of the present application and the existing speckle dot pattern 250 of the existing laser emission module both belong to the same target space (the laser emission modules of the two are also arranged at the same position).

The reduction lens 140 in the present application is a lens with a preset reduction magnification. Which can reduce the diameter of a spot formed by each beam in such a manner that the angle of view of the laser emission module 100 is reduced. The specific structure will be described below schematically in two embodiments, it should be understood that the present invention should not be construed as being limited thereto.

One of them is:

optionally, the zoom-out lens 140 includes a first positive lens 141 and a negative lens 142; the light beam emitted from the diffractive optical element 130 is converged by the first positive lens 141 and then expanded and projected by the negative lens 142, wherein the distance from the negative lens 142 to the first positive lens 141 is smaller than the focal length of the first positive lens 141.

Illustratively, the reduction lens 140 includes a first positive lens 141 and a negative lens 142. The two are arranged as shown in fig. 2, and the negative lens 142 is located behind the first positive lens 141 according to the light propagation path. The light beam emitted from the diffractive optical element 130 firstly enters the first positive lens 141, and under the converging action of the first positive lens 141, the light beam converges in the focal direction on the main optical axis of the first positive lens 141, and in order to achieve the purpose of reducing the field angle of the light beam emitted from the diffractive optical element 130 to reduce the diameter of the light spot, the optical center of the negative lens 142 should be located between the optical center of the first positive lens 141 and the focal point of the first positive lens 141, that is, the distance from the negative lens 142 to the first positive lens 141 should be smaller than the focal length of the first positive lens 141, where it should be noted that the distance from the negative lens 142 to the first positive lens 141 refers to the distance from the optical center of the negative lens 142 to the optical center of the first positive lens 141. The light beam converged by the first positive lens 141 propagates toward the focal point of the first positive lens 141, and before reaching the focal point of the first positive lens 141, the light beam enters the negative lens 142 at an angle, and under the beam expanding effect of the negative lens 142, the converged light beam is diverged at a certain angle, which includes three divergence situations:

first, the diverging light beam is still a converging light beam, and in this case, it is necessary to ensure that the diameter of the light spot formed by the light beam at the target space is smaller than the diameter of the light spot formed by each parallel light beam in the target space before entering the reduction lens 140.

Secondly, the beam after divergence is a diverging beam, and in this case, it is necessary to ensure that the diameter of the light spot formed by the beam in the target space is smaller than the diameter of the light spot formed by each parallel beam in the target space before entering the reduction lens 140.

Thirdly, the beam after being diverged is a parallel beam, and it is also necessary to ensure that the diameter of the spot formed by the beam in the target space is smaller than the diameter of the spot formed by each parallel beam in the target space before entering the reduction lens 140. As shown in fig. 2.

That is, the first positive lens 141 and the negative lens 142 are combined to reduce the angle of view of the light beam emitted from the diffractive optical element 130 and the diameter of the light spot thereof, and the lens having such a configuration has a small volume and a low manufacturing cost.

Optionally, the distance from the negative lens 142 to the first positive lens 141 is equal to the absolute value of the sum of the focal length of the first positive lens 141 and the focal length of the negative lens 142.

Illustratively, the distance from the negative lens 142 to the first positive lens 141 is equal to the absolute value of the sum of the focal length of the first positive lens 141 and the focal length of the negative lens 142. Here, the focal length of the first positive lens 141 should be positive and the focal length of the negative lens 142 should be negative, defined by the focal lengths of the positive and negative lenses. That is, in fig. 2, the focal point of the first positive lens 141 and the focal point of the negative lens 142 coincide. At this time, it can be ensured that after the parallel light beams enter the first positive lens 141 and are converged, the light beams are emitted again in the form of parallel light by the divergence of the negative lens 142, and the diameter of the parallel light beams emitted from the negative lens 142 is smaller than that of the corresponding parallel light beams before entering the first positive lens 141. When the light beam after being emitted by the reduction lens 140 is parallel light, the limitation of the laser emission module 100 in the application to the position of the subsequent object 500 to be detected in the space can be effectively reduced, and the high efficiency and the application range of the laser emission module 100 in the application are improved.

In addition, the optical track length (which can characterize the length of the zoom-out lens 140 to a certain extent) is the sum of the focal length of the first positive lens 141 and the focal length of the negative lens 142, so that the first positive lens 141 and the negative lens 142 having the focal lengths meeting the requirements are selected according to the size of the zoom-out lens 140 during actual setup and manufacture. The requirements of different customers can be met conveniently, and the universality of actual production and application is improved.

It should be noted that when the parallel light beams collimated by the collimator lens 120 pass through the diffractive optical element 130, the parallel light beams are diffracted at a specific angle, the light beams in different diffraction orders can be approximately regarded as having a certain tiny angle, and the speckle having a certain field angle is finally formed by overlapping a plurality of tiny angles. However, the light beams in each diffraction order can also be regarded as approximately parallel light, that is, for the reducing lens 140, the light beams of different diffraction orders emitted from the diffractive optical element 130 are incident on the reducing lens 140 in a parallel light manner, except that the light beams of different diffraction orders are incident on the reducing lens 140 at different incident angles, and the incident angles are related to the diffraction orders, wherein the angles can be calculated by a grating equation, for example, as shown in fig. 4, the first light beam 210, the second light beam 220, and the third light beam 230 belong to different diffraction orders and are respectively incident on the reducing lens 140 at different angles, but the light beams of each diffraction order are also parallel light. When the first positive lens 141 and the negative lens 142 are disposed at positions where the distance from the negative lens 142 to the first positive lens 141 is equal to the absolute value of the difference between the focal length of the first positive lens 141 and the focal length of the negative lens 142, the light beams in each diffraction order are incident on the first positive lens 141 as parallel light and exit from the negative lens 142 as parallel light. I.e., the entire zoom-out lens 140 has no focal length.

Alternatively, the preset reduction magnification is equal to the ratio of the focal length of the negative lens 142 to the focal length of the first positive lens 141.

For example, in the embodiment where the zoom-out lens 140 is the first positive lens 141 and the negative lens 142, as shown in fig. 2, it may be equal to a ratio of a focal length of the negative lens 142 to a focal length of the first positive lens 141, wherein when focal points of the first positive lens 141 and the negative lens 142 coincide, according to the principle of similar triangles, it can be derived that the preset zoom-out magnification is equal to a ratio of a focal length of the negative lens 142 to a focal length of the first positive lens 141. For example, when the laser emission module 100 in the present application is applied at a long distance, the reduction lens 140 reduces the area of the light beam (the area formed by the speckle dot pattern 260) by a preset reduction ratio of 0.5 squared without significantly affecting the total energy contained in the light beam. Compared with the laser emitting module 100 without the reduction lens 140, the structure of the laser emitting module 100 with the reduction lens 140 (i.e., the laser emitting module 100 in the present application) has the advantages that the number of light spots in a unit area is increased by 4 times, the diameter of the light spots is reduced by 0.5 time, and the energy density of the light spots is increased by 4 times. As shown in fig. 7 and 8, at the same distance, the area of the reduced speckle dot pattern 260 is significantly smaller than that of the non-reduced speckle dot pattern 260, and the number of speckle dots per unit area is larger, resulting in a larger energy density. The problems that the number of scattered spots in a unit area is small, the energy density of light spots is low and the like when the laser emission module 100 is far away are solved, the quality of the speckle spot pattern 260 when the laser emission module 100 is far away projected is effectively improved, and the definition and the contrast are improved. In addition, it is also possible to implement reduction of the magnification of the field angle and the spot diameter to different degrees by adjusting the focal lengths of the first positive lens 141 and the negative lens 142 so as to change the value of the preset reduction magnification.

Alternatively, the first positive lens 141 is a biconvex lens and the negative lens 142 is a plano-concave lens.

For example, as shown in fig. 2, the first positive lens 141 may be a biconvex lens, and since the focal lengths of both sides of the biconvex lens are the same, the requirement for installation may be reduced, and the installation efficiency may be improved. Meanwhile, the biconvex lens has two effective curvature variables when focusing a light path, and can be matched with each other to better eliminate aberration. The negative lens 142 is a plano-concave lens, which can effectively reduce the manufacturing cost. In addition, in other embodiments of the present application, the first positive lens 141 may also be a plano-convex lens, and the negative lens 142 may also be a biconcave lens.

The other one is as follows:

optionally, the zoom-out lens 140 includes a second positive lens 143 and a third positive lens 144; the light beams emitted from the diffractive optical element 130 are converged by the second positive lens 143 and the third positive lens 144 in sequence and then projected, wherein the distance from the third positive lens 144 to the second positive lens 143 is greater than the focal length of the second positive lens 143.

Illustratively, as shown in fig. 3, the reduction lens 140 includes a second positive lens 143 and a third positive lens 144. The two are arranged as shown in fig. 3, and the third positive lens 144 is located behind the second positive lens 143 according to the path of the light. The light beam emitted from the diffractive optical element 130 firstly enters the second positive lens 143, and under the converging action of the second positive lens 143, the light beam converges in the focal direction on the main optical axis of the second positive lens 143, and for the purpose of reducing the field angle of the light beam emitted from the diffractive optical element 130 and the diameter of the light spot thereof, the setting position of the optical center of the third positive lens 144 should be located outside the focal point of the second positive lens 143, that is, the distance from the third positive lens 144 to the second positive lens 143 should be greater than the focal length of the second positive lens 143. The light beam converged by the second positive lens 143 propagates toward the focal point of the second positive lens 143, and after reaching the focal point of the second positive lens 143, the light beam enters the third positive lens 144 in a diffused manner at an angle, and under the converging action of the third positive lens 144, the light beam which is diffused after passing through the focal point of the second positive lens 143 is converged at a certain angle, which includes three converging conditions:

first, the converged light beam is a converged light beam, and in this case, it is required to ensure that the diameter of a light spot formed by the light beam at the target space is smaller than the diameter of a light spot formed by each parallel light beam in the target space before entering the reduction lens 140.

Secondly, the converged light beam is still a divergent light beam, and in this case, it is required to ensure that the diameter of a light spot formed by the light beam at the target space is smaller than the diameter of a light spot formed by each parallel light beam in the target space before entering the reduction lens 140.

Thirdly, the converged light beams are parallel light beams, and it is also necessary to ensure that the diameter of the light spot formed by the light beams in the target space is smaller than the diameter of the light spot formed by each parallel light beam in the target space before the light beam enters the reduction lens 140. As shown in fig. 3.

That is, the second positive lens 143 and the third positive lens 144 are combined to reduce the angle of view of the light beam emitted from the diffractive optical element 130 and the diameter of the light spot, and the configuration is simple and the manufacturing cost is low.

Optionally, the distance between the second positive lens 143 and the third positive lens 144 is equal to the sum of the focal length of the second positive lens 143 and the focal length of the third positive lens 144.

For example, when the distance between the second positive lens 143 and the third positive lens 144 is set to the sum of the focal lengths of the two positive lenses, that is, the focal points of the two lenses coincide, the parallel light beams incident on the second positive lens 143 can still exit in the form of parallel light beams when exiting through the third positive lens 144, but the diameter of the exiting parallel light beams is smaller than that of the entering parallel light beams. Here, the focal length values of the second positive lens 143 and the third positive lens 144 should be both positive values, defined by the focal length of the positive lenses. The incident parallel light is adopted and emitted in the form of parallel light, so that the diameter of the emitted parallel light beam is basically not changed, namely the diameter of a scattered spot formed by projection in a target space is basically in a constant value, the diameter of the formed scattered spot is not changed due to the change of the position of the target space, the limitation on the position of the object 500 to be detected is reduced, and the application range of the laser emission module 100 is enlarged.

When the focal points of the second positive lens 143 and the third positive lens 144 coincide, it can be derived that the preset reduction magnification is equal to the ratio of the third positive lens 144 to the second positive lens 143 in the embodiment where the reduction lens 140 is the second positive lens 143 and the third positive lens 144 according to the triangle-like principle. The operator can flexibly adjust the reduction ratio according to actual requirements.

Alternatively, the light source module 110 includes a plurality of vertical cavity surface emitting lasers arranged in a matrix arrangement.

For example, when the light source module 110 is a vertical cavity surface emitting laser, it may be in the form of one, or two or more. When two, the spacing is provided, and the spacing may be between 5 microns and 50 microns. When a plurality of light sources are provided, the light sources may be arranged randomly, i.e., in an irregular two-dimensional pattern, or may be arranged in a matrix, i.e., two-dimensional light sources arranged in a two-dimensional pattern, and the pitch of the arrangement may be 5 to 50 micrometers. As shown in fig. 6, only the layout is given for 9. It should be noted that a Vertical-cavity surface-Emitting Laser (VCSEL, also called Vertical-cavity surface-Emitting Laser) is a semiconductor, and Laser light is emitted perpendicularly to the top surface. Compared with a traditional light source, the VCSEL has the advantages of small size, small divergence angle, energy concentration and the like, and the laser emission module 100 projects a pattern with high definition and high contrast in a long-distance target space. In addition, the black grid lines in fig. 7 and 8 are speckle point imaging regions which are manually defined corresponding to the 9 VCSELs respectively for convenience of description and comparison, and actually do not exist.

Optionally, the collimating mirror 120 comprises a micro-lens array; the plurality of microlens units in the microlens array are arranged in one-to-one correspondence with the plurality of vertical cavity surface emitting lasers.

Illustratively, the collimating lens is a micro-lens array (MLA), and each micro-lens unit in the MLA corresponds to one VCSEL, and each VCSEL is located at the focal length of the corresponding MLA. The light interference among the VCSELs can be reduced to some extent, and the collimation effect of the collimating mirror 120 is improved.

The utility model discloses on the other hand of embodiment provides a 3D imaging device, including receiving module 400, processing module 300 and any kind of laser emission module 100 of the aforesaid, receiving module 400 and laser emission module 100 set up in same reference surface, receiving module 400 is used for gathering the speckle dot pattern 260 that laser emission module 100 throws, and processing module 300 is connected with receiving module 400 electricity for calculate out the depth image according to speckle dot pattern 260.

For example, the laser emitting module 100 is applied to 3D imaging, as shown in fig. 5, and further includes a receiving module 400 and a processing module 300. The receiving module 400 and the laser transmitting module 100 are arranged on the same reference plane, and because the light beam emitted by the laser transmitting module 100 has a certain field angle, the receiving module 400 receives the patterns within a certain angle range when receiving the patterns, therefore, the target space is just located in the range where the receiving module 400 and the laser transmitting module 100 are overlapped with each other, thereby facilitating accurate identification and receiving. After the laser emitting module 100 projects the speckle dot pattern 260 into the target space, because the speckle dot pattern 260 is displayed in the target space after being reduced by the reduction lens 140 with the preset reduction ratio, the area of the whole speckle dot pattern 260 is reduced, thereby increasing the speckle dot density in the unit area, and simultaneously reducing the diameter of the light beam forming each scattered dot, thereby increasing the energy density of each scattered dot, so that when the 3D imaging device is applied in a long distance, the texture definition, the contrast and the like of the speckle dot pattern 260 projected by the laser emitting module 100 in the target space are effectively improved, thereby enabling the receiving module 400 to collect a clearer image, and facilitating the processing module 300 electrically connected with the receiving module 400 to calculate and analyze the more accurate depth information of the object in the target space according to the clear and high-contrast speckle dot pattern 260, and the depth information measurement with higher precision is realized.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A laser emission module, comprising: the device comprises a light source component, a collimating mirror, a diffraction optical element and a reduction lens; and the light beam emitted from the light source component enters the diffractive optical element after passing through the collimating mirror, and the light beam emitted from the diffractive optical element reduces the field angle of the light beam emitted from the diffractive optical element by a preset reduction magnification through the reduction lens to form a speckle point pattern in a target space.

2. The laser transmitter module of claim 1, wherein the demagnifying lens comprises a first positive lens and a negative lens; the light beams emitted from the diffractive optical element are converged by the first positive lens and then subjected to beam expanding projection by the negative lens, wherein the distance between the negative lens and the first positive lens is smaller than the focal length of the first positive lens.

3. The laser transmitter module of claim 2, wherein the distance from the negative lens to the first positive lens is equal to the absolute value of the sum of the focal length of the first positive lens and the focal length of the negative lens.

4. The laser transmitter module of claim 3, wherein the predetermined demagnification is equal to a ratio of a focal length of the negative lens to a focal length of the first positive lens.

5. The laser transmitter module of any of claims 2 to 4, wherein the first positive lens is a biconvex lens and the negative lens is a plano-concave lens.

6. The laser transmitter module of claim 1, wherein the demagnifying lens comprises a second positive lens and a third positive lens; and the light beams emitted from the diffractive optical element are converged by the second positive lens and the third positive lens in sequence and then projected, wherein the distance from the third positive lens to the second positive lens is greater than the focal length of the second positive lens.

7. The laser transmitter module of claim 6, wherein the second positive lens and the third positive lens have a distance equal to the sum of the focal length of the second positive lens and the focal length of the third positive lens.

8. The laser module as recited in claim 1, wherein the light source assembly comprises a plurality of vertical cavity surface emitting lasers arranged in a matrix arrangement.

9. The laser emitter module of claim 8, wherein the collimating mirror comprises a micro-lens array; and the plurality of micro lens units in the micro lens array are arranged in one-to-one correspondence with the plurality of vertical cavity surface emitting lasers.

10. A 3D imaging device, comprising a receiving module, a processing module and the laser emitting module according to any one of claims 1 to 9, wherein the receiving module and the laser emitting module are disposed on the same reference plane, the receiving module is configured to collect a speckle dot pattern projected by the laser emitting module, and the processing module is electrically connected to the receiving module and configured to calculate a depth image according to the speckle dot pattern.

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