Beam splitting optical module and manufacturing method thereof

Abstract

The present invention discloses a beam splitting optical module, comprising: a light emitting device; and a diffractive optical element, wherein the diffractive optical element is arranged on the light emitting path of the light emitting device and is configured to modulate the incident light to project at least two groups of light beams and form at least two groups of light spots of corresponding numbers on a target surface, wherein the at least two groups of light beams have different polarization directions from each other and / or different optical paths from the light emitting device to the target surface.

Description

Technical Field

[0001] The present invention relates to the field of optical technology, in particular to the technical field of modulation and projection of diffractive optical elements. Background Art

[0002] At present, mobile phone manufacturers have begun to gradually adopt structured light 3D sensing technology. Structured light technology (StructuredLight) is an active triangulation technology. Its basic principle is: a laser projector projects controllable photoelectric, light strips or light surfaces onto the surface of an object to form feature points, and the camera captures the image to obtain the projection angle of the feature points. Then, according to the calibrated spatial direction and position parameters, the distance between the feature points and the camera lens principal point is calculated using the triangulation measurement principle to obtain the 3D shape of the detected object, realize face recognition, 3D modeling, etc. Currently, the commonly used structured light 3D sensing technology includes pattern (dot matrix, or speckle) projection module and imaging module. As described in PrimeSense's patent US9825425. Compared with 2D recognition, the accuracy of 3D recognition has been significantly improved, gradually approaching or surpassing the recognition accuracy of the human eye, and showing great commercial value. In the Optics Express paper, Xiao Huang et al. proposed to use polarization structured light encoding to improve the recognition accuracy of 3D modeling in complex background light environments.

[0003] At present, structured light solutions are mainly used in mobile applications such as Face ID face unlocking and payment, Apple Pay mobile payment, and secure payment products such as cash registers, facial recognition products such as authentication comparison, gates, security products such as smart door locks, and non-mobile applications such as unmanned supermarkets. These scenarios have high requirements for recognition accuracy, so how to improve recognition accuracy is an urgent need for all manufacturers. At present, the main structural element DOE of the structured light projection module is limited by manufacturing capabilities, and the minimum feature size cannot be further reduced, resulting in the density of feature points of the speckle pattern, point size and number cannot be improved. According to known technical solutions, polarized light is usually generated by multiple modules or complex systems (such as liquid crystal display modules LCD), and dot matrix is ​​generated by DOE, and then more three-dimensional information is extracted. There is currently no compact, low-cost polarization structured light solution. However, for the consumer electronics industry, miniaturization and low-cost solutions are very important.

[0004] The contents of the background technology section are merely the technologies known to the inventors and do not necessarily represent the prior art in the field. Summary of the invention

[0005] In view of this, the present invention proposes a beam splitting optical module, comprising: a light emitting device; and a diffractive optical element, wherein the diffractive optical element is arranged on the light output path of the light emitting device and is configured to modulate the incident light to project at least two groups of light beams and form at least two groups of light spots of corresponding numbers on a target surface, wherein the at least two groups of light beams have different polarization directions with respect to each other, and / or different optical paths from the light emitting device to the target surface.

[0006] According to one aspect of the present invention, a polarization modulation element is provided between the light emitting device and the diffractive optical element, the polarization modulation element is configured to modulate the light emitted by the light emitting device into at least two groups of polarized light with different polarization directions, the number of which corresponds to the at least two groups of light beams, the diffractive optical element is configured to modulate the at least two groups of polarized light to project the at least two groups of light beams, wherein the polarization modulation element is preferably a polarization grating and / or a polarizing film, and the light emitting device is preferably a vertical cavity surface emitting laser or an edge emitting laser or an LED. The embodiment of the present invention optimizes the design of DOE using the characteristics of polarized light, which can reduce the size of feature points and increase the number of feature points exponentially, thereby improving the recognition accuracy. The present invention controls the light emitting cavity to generate specific polarized light by making a diffractive optical structure on the chip surface of a semiconductor light emitting device (such as VCSEL, LED). For example, a diffraction grating structure is designed for the VCSEL light source point to generate two groups of polarized light. Each group of polarized light can project a group of feature point patterns through the polarization optimized DOE. Compared with the traditional solution, the number of points is doubled, which can greatly improve the recognition accuracy.

[0007] According to one aspect of the present invention, the diffractive optical element is configured to project two groups of light beams and form two groups of light spots on the target surface, or to project four groups of light beams and form four groups of light spots on the target surface.

[0008] According to one aspect of the present invention, the beam splitting optical module also includes a beam splitting element, which is arranged between the light emitting device and the diffractive optical element and is configured to split the received light into at least two groups of beam lights, the number of which corresponds to the at least two groups of light beams. The diffractive optical element is configured to receive the at least two groups of beam lights and modulate and project the at least two groups of light beams.

[0009] According to one aspect of the present invention, the beam splitting element is a polarization beam splitting element configured to split the received light into at least two groups of polarized lights with different polarization directions.

[0010] According to one aspect of the present invention, the beam splitting element is a non-polarizing beam splitter.

[0011] According to one aspect of the present invention, the diffractive optical element is configured to modulate incident light with different polarization directions to form at least two sets of distinctive light spot patterns on the target surface.

[0012] The present invention also provides a light modulation method, comprising: receiving light emitted by a light-emitting device; and modulating the light from the light-emitting device through a diffractive optical element to project at least two groups of light beams and form at least two groups of light spots of corresponding numbers on a target surface, wherein the at least two groups of light beams have different polarization directions and / or different optical paths from the light-emitting device to the target surface.

[0013] According to one aspect of the present invention, the light modulation method further comprises modulating the light emitted by the light emitting device into at least two groups of polarized light with different polarization directions by a polarization modulation element, the number of which corresponds to the at least two groups of light beams, and the diffractive optical element is configured to modulate the at least two groups of polarized light to project the at least two groups of light beams, wherein the polarization modulation element is preferably a polarization grating and / or a polarizing film, and the light emitting device is preferably a vertical cavity surface emitting laser or an edge emitting laser or an LED.

[0014] According to one aspect of the present invention, the diffractive optical element is configured to project two groups of light beams and form two groups of light spots on the target surface, or to project four groups of light beams and form four groups of light spots on the target surface.

[0015] According to one aspect of the present invention, the light modulation method also includes dividing the received light into at least two groups of beam lights by a beam splitter element arranged between the light emitting device and the diffractive optical element, the number of which corresponds to the at least two groups of beams, and the diffractive optical element is configured to receive the at least two groups of beam lights, and modulate and project the at least two groups of beams.

[0016] According to one aspect of the present invention, the beam splitting element is a polarization beam splitting element configured to split the received light into at least two groups of polarized lights with different polarization directions; or the beam splitting element is a non-polarization beam splitter.

[0017] According to one aspect of the present invention, the diffractive optical element is configured to modulate incident light with different polarization directions to form at least two sets of distinctive light spot patterns on the target surface.

[0018] The present invention also provides an electronic device, comprising: the beam splitting optical module as described above; a camera, which collects the pattern formed by the light spot; and a processing device, which receives the pattern collected by the camera and processes the pattern.

[0019] The present invention also provides a method for manufacturing a beam splitting optical module, comprising: providing a substrate for the optical module; preparing a light-emitting device on the substrate; forming a diffractive optical element on the light emission path of the light-emitting device, wherein the diffractive optical element is configured to modulate the incident light to project at least two groups of light beams and form at least two groups of light spots of corresponding numbers on a target surface, wherein the at least two groups of light beams have different polarization directions and / or different optical paths from the light-emitting device to the target surface.

[0020] According to one aspect of the present invention, the manufacturing method also includes: arranging a polarization modulation element between the light-emitting device and the diffractive optical element, the polarization modulation element being configured to modulate the light emitted by the light-emitting device into at least two groups of polarized light with different polarization directions, the number corresponding to the at least two groups of light beams, the diffractive optical element being configured to modulate the at least two groups of polarized light to project the at least two groups of light beams, wherein the polarization modulation element is preferably a polarization grating and / or a polarizing film, and the light-emitting device is preferably a vertical cavity surface emitting laser or an edge emitting laser or an LED.

[0021] According to one aspect of the present invention, the manufacturing method also includes: further comprising: setting a beam splitter element between the light emitting device and the diffractive optical element, the beam splitter element being configured to split the received light into at least two groups of beam lights, the number of which corresponds to the at least two groups of beams, the diffractive optical element being configured to receive the at least two groups of beam lights, and modulate and project the at least two groups of beams. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0023] Figure 1 A beam splitting optical module according to a first embodiment of the present invention is shown;

[0024] Figure 2 A beam splitting optical module according to a second embodiment of the present invention is shown;

[0025] Figure 3 An example of a light emitting device is shown;

[0026] Figure 4 shows a pattern of random light emitting points of a light emitting device without a polarization modulating element;

[0027] Figure 5 It shows that after the polarization modulation element is set, the light emitted by each light emitting device is modulated into polarized light in two directions;

[0028] Figure 6shows a projected light spot pattern according to one embodiment of the present invention;

[0029] Figure 7 A projected light spot pattern according to another embodiment of the present invention;

[0030] Figure 8 A beam splitting optical module according to another embodiment of the present invention is shown;

[0031] Fig. 9 A light modulation method according to an embodiment of the present invention is shown;

[0032] Fig.10 An electronic device according to another embodiment of the present invention is shown;

[0033] Fig.11 A method for manufacturing a beam splitting optical module according to an embodiment of the present invention is shown; and

[0034] Fig.12 A beam splitting optical module according to another embodiment of the present invention is shown. DETAILED DESCRIPTION

[0035] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0036] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0037] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is lower in level than the second feature.

[0039] The disclosure below provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplicity and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides various specific examples of processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0040] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0041] Figure 1 FIG. 1 shows a beam splitting optical module 100 according to a first embodiment of the present invention. Figure 1As shown, the beam splitting optical module 100 includes: a light emitting device 101 and a diffractive optical element DOE 103. The diffractive optical element 103 is disposed on the light emission path of the light emitting device 101, and is configured to modulate the incident light to project at least two groups of light beams and form at least two groups of light spots of corresponding numbers on a target surface 105, wherein the polarization directions of the at least two groups of light beams are different from each other, and / or the optical paths from the light emitting device 101 to the target surface 105 are different. The following is a detailed description.

[0042] like Figure 1 As shown, the light emitting device 101 can be a polarized light source or a non-polarized light source. The light emitting device 101 emits a light beam 102, and the diffractive optical element 103 modulates the incident light and projects a first group of light beams 104 and a second group of light beams 106, forming two corresponding groups of light spots on the target surface 105. The first group of light beams 104 and the second group of light beams 106 are different in some optical properties, such as different polarization directions, and / or different optical paths from the light emitting device 101 to the target surface 105. In addition to the polarization direction and the optical path, those skilled in the art can conceive of using other optical properties. These are all within the scope of the present invention. The target surface 105 can be a face, or other surface to be identified or illuminated, which can be either flat or curved. At the same time, those skilled in the art can understand that the first group of light beams and the second group of light beams in the present invention are relative concepts. As described above, light beams of different groups are different in some optical properties, while the light beams in the same group of light beams are the same in these optical properties, such as the same polarization direction, and / or the same optical path from the light emitting device 101 to the target surface 105.

[0043] Compared with the prior art, the beam splitting optical module 100 of the first embodiment of the present invention can modulate the incident light to project two sets of light spots, which do not completely overlap in position and may carry other information such as polarization information. The density and number of feature points of the speckle pattern are further improved by the solution of the present invention, thereby improving the recognition accuracy.

[0044] Figure 1 The description is made by taking two groups of light beams and two groups of light spots as an example. Those skilled in the art may adopt technical solutions with more groups of light beams and more groups of light spots on this basis, which are all within the scope of the present invention.

[0045] The preferred embodiments of the beam splitting optical module of the present invention are described below.

[0046] Figure 2 FIG. 2 shows a beam splitting optical module 200 according to a second embodiment of the present invention. Figure 2As shown, the light emitting device 201 emits two groups of polarized light 2021 and 2022, wherein the polarized light 2021 is, for example, polarized light in the X direction, and the polarized light 2022 is, for example, polarized light in the Y direction. The polarized light 2021 and 2022 are incident on the diffractive optical element 203, and the diffractive optical element 203 is configured to modulate the two groups of polarized light 2021 and 2022 according to the polarization state of the incident light to project two groups of light beams 204 and 206, forming two groups of light spots on the target surface 205, wherein the light beams 204 and 206 have different polarization directions.

[0047] Figure 3 An example of a light emitting device 201 is shown. Figure 3 As shown, the light emitting device 201 includes a vertical cavity surface emitting laser (VCSEL) 2011 and a polarization modulation element 2013, and the polarization modulation element 2013 is configured to modulate the light emitted by the light emitting device 201 into at least two groups of polarized light with different polarization directions, the number of which corresponds to the at least two groups of light beams, wherein the polarization modulation element 2013 is preferably a polarization grating. Optionally, the polarization modulation element 2013 can also be realized by attaching polarizing films in multiple directions to the vertical cavity surface emitting laser 2011. It is easy to understand that in addition to the vertical cavity surface emitting laser, the light emitting device 201 can also include an edge emitting laser or an LED.

[0048] The embodiments of the present invention can control the light-emitting cavity to produce specific polarized light by manufacturing a diffraction optical structure (such as a polarization grating) on ​​the chip surface of a semiconductor light-emitting device (such as VCSEL, LED). For example, a diffraction grating structure is designed for the VCSEL light source point to generate two groups of polarized light. Each group of polarized light can project a set of characteristic point patterns through the diffraction optical element DOE with polarization optimization design. Compared with the traditional scheme, the number of points is doubled, which can greatly improve the recognition accuracy. This embodiment mainly involves processing a diffraction optical structure on the upper surface of the VCSEL light-emitting cavity, which can make the VCSEL emit linear polarized light with a specific polarization state. Figure 2 As shown in the figure, a grating is processed on the upper surface of the VCSEL to realize that a single point light source of the VCSEL outputs polarized light in two directions. Combined with the optimized DOE components, a Figure 6 The dot matrix shown.

[0049] This embodiment makes full use of the characteristics of polarized light, designs the surface of the VCSEL random light source point into a metasurface, so that it emits linear polarized light in the X direction and linear polarized light in the Y direction, and optimizes the polarization DOE structure according to the direction of the polarized light to generate two sets of polarized structured light dot arrays. Compared with the traditional design, the number of feature points is doubled. In addition, the size of the feature points can be reduced, further improving the density of the feature points.

[0050] It is easy to understand that the light emitting device of this embodiment may include a VCSEL light source matrix.

[0051] The solution described in this embodiment can increase the number of feature points of the structured light projection module exponentially and reduce the size of the feature points, thereby improving recognition accuracy.

[0052] If the light emitted by the light source itself is non-polarized light, it can also be converted into polarized light in different directions by a polarization modulation element (such as a polarization grating) on ​​the upper surface of the VCSEL, thereby forming different dot patterns for different polarization directions.

[0053] Figure 3 It is shown that the light emitted by the VCSEL 2011 is modulated into polarized light in at least two directions by the polarization modulation element 2013. The present invention is not limited to generating polarized light by a single polarization modulation element, and at least two polarized light sources may be directly provided to generate polarized light in at least two directions. All of these are within the protection scope of the present invention.

[0054] Figure 4 The pattern of random light emitting points of the vertical cavity surface emitting laser 2011 without the polarization modulation element 2013 is shown. Figure 5 It is shown that after the polarization modulation element 2013 is provided, the light emitted by each vertical cavity surface emitting laser 2011 is modulated into polarized light in two directions, namely, polarized light in the X direction and polarized light in the Y direction. Figure 6 It shows that after the light emitted from the polarization modulation element 2013 is modulated by the diffractive optical element 203, two groups of light spots are formed on the target surface, thereby doubling the number of projected light spots.

[0055] The diffractive optical element 203 is configured to modulate incident light with different polarization directions to form at least two groups of light spots with different patterns on the target surface. In the present invention, "at least two groups of light spots with different patterns" means that there are some differences between the two groups of light spots, such as the difference in the positions of the light spots, the difference in the polarization directions of the light rays forming the light spots, the difference in the optical path length of the light rays from the light source to the target surface, etc.

[0056] The above description is based on two groups of polarized light as an example. It is easy for a person skilled in the art to understand that the present invention can use more groups of polarized light. Figure 7As shown, the light emitted by each vertical cavity surface emitting laser 2011 passes through the polarization modulation element 2013 and is modulated into polarized light in four directions, namely, polarized light in the α direction, polarized light in the β direction, polarized light in the γ direction, and polarized light in the δ direction, so that a single point light source of the VCSEL outputs polarized light in four directions. The diffractive optical element 2013 modulates the polarization direction of the polarized light and projects four groups of light spots, wherein the polarization direction of the light in each group of light spots is different. In this way, compared with the technical solution of directly projecting the light emitted by the vertical cavity surface emitting laser 2011 to the diffractive optical element 2013, each polarized light direction forms a dot matrix, and the number of light spots becomes four times.

[0057] The above description is mainly based on the vertical cavity surface emitting laser as an example. The light emitting device 201 is not limited to the vertical cavity surface emitting laser, and may also include other types of polarized or non-polarized light sources.

[0058] Figure 8 FIG. 3 shows a beam splitting optical module 300 according to another preferred embodiment of the present invention. Figure 3 As shown, in addition to the light-emitting device 301 and the diffractive optical element 303, the beam splitting optical module 300 also includes a beam splitting element 307, which is arranged between the light-emitting device 301 and the diffractive optical element 303, and is configured to split the received light into at least two groups of beam lights, the number of which corresponds to the at least two groups of light beams, and the diffractive optical element 303 is configured to receive the at least two groups of beam lights, and modulate and project the at least two groups of light beams to form at least two groups of light spots of corresponding number on the target surface 305.

[0059] According to a preferred embodiment, the beam splitting element 307 is a polarization beam splitting element, which is configured to split the received light into at least two groups of polarized light with different polarization directions, which are incident on the diffractive optical element 303 and are emitted as at least two groups of light with different polarization directions of a corresponding number, forming a corresponding number of light spots.

[0060] According to a preferred embodiment of the present invention, Figure 8 As shown, the beam splitter element 307 is a polarization beam splitter, including a polarization beam splitting surface 3071 and a reflection surface 3072. The polarization beam splitting surface 3071 can separate the incident light 302 according to its polarization direction. For example, the polarized light 3022 in the X direction is emitted to the diffractive optical element 303 through refraction; the polarized light 3021 in the Y direction is reflected by the polarization beam splitting surface 3071, and then reflected by the reflection surface 3072, and then incident on the diffractive optical element 303. For the polarized light 3021 in the Y direction, its light source virtual image is 301', as shown in FIG. Figure 8 As shown, the optical path of the Y-direction polarized light 3021 is longer, and the optical path of the X-direction polarized light 3022 is shorter.

[0061] According to one embodiment, the beam splitting element 307 may be a non-polarizing beam splitter.

[0062] By setting a beam splitter / beam splitting element, the distance between the light emitting device and the diffractive optical element DOE can be reduced, and the number of points can be increased at the same time, and a polarization beam splitter can be directly added to the light source and DOE. If the device uses a material with a refractive index of 1.5, the optical path of the polarized light 3022 in polarization direction 1 will increase by about 50%, and the optical path of the polarized light 3021 in polarization direction 2 will increase by about 100%. In this way, a dot matrix projection module combining long focal length and short focal length can be formed, which is beneficial to increase the working distance. According to the object-image relationship, a light beam with a long optical path corresponds to a long focal length, and a light beam with a short optical path corresponds to a short focal length. If the light emitting device is non-polarized and the beam splitter is an ordinary beam splitter, the above optical path diagram scheme is also applicable. The optical paths of the light beams separated by the beam splitter will be different, resulting in different focal lengths. With Figure 8 For example, for a non-polarized light emitting device, different regions of the diffractive optical element 303 may have different microstructures (for example, Figure 8 In the embodiment, the microstructure of the upper part of the diffractive optical element 303 is different from that of the lower part, and the incident light beams with different optical paths are modulated respectively. The incident light beams are modulated accordingly according to the length of the optical path, thereby forming different focal lengths. For polarized light emitting devices, different microstructures can be arranged in different regions on the diffractive optical element 303 to modulate polarized light with different polarization directions accordingly, or different microstructures do not need to be arranged in different regions. Figure 1 and Figure 2 In the case shown, light beams with different polarization directions are incident on the diffractive optical element, and the diffractive optical element will be modulated accordingly according to the polarization direction of the incident light. If the light source is divided into more than two light beams, the above optical path diagram scheme is also applicable. Figure 8 The two groups of light spots are shown as being located on different planes, which does not constitute a limitation to the present invention, and the two groups of light spots may also be located on the same plane.

[0063] Figure 8 The embodiments can be used with Figure 2-7 In combination with the embodiments, for example Figure 8 The light emitting device 301 may include a polarization modulation element, so as to modulate the light of a single point light source into polarized light in multiple directions, for example, polarized light in two directions, and then be incident on the beam splitting element 307 .

[0064] Fig. 9 FIG. 4 shows a light modulation method 400 according to an embodiment of the present invention. Fig. 9 As shown, the light modulation method 400 includes:

[0065] In step S401, light emitted by a light emitting device is received.

[0066] In step S402, the light from the light emitting device is modulated by a diffractive optical element to project at least two groups of light beams and form at least two groups of light spots of corresponding numbers on the target surface, wherein the at least two groups of light beams have different polarization directions and / or different optical paths from the light emitting device to the target surface.

[0067] The light modulation method 400 of the present embodiment can be performed by using the beam splitting optical modules 100 , 200 , 300 described above.

[0068] According to a preferred embodiment of the present invention, the light modulation method 400 further comprises modulating the light emitted by the light emitting device into at least two groups of polarized light with different polarization directions by a polarization modulation element, the number of which corresponds to the at least two groups of light beams, wherein the diffractive optical element is configured to modulate the at least two groups of polarized light to project the at least two groups of light beams, wherein the polarization modulation element is preferably a polarization grating and / or a polarizing film, and the light emitting device is preferably a vertical cavity surface emitting laser or an edge emitting laser or an LED. Figure 5 The figure shows the X-direction polarized light and Y-direction polarized light formed after the light emitted by the vertical cavity surface emitting laser passes through the polarization modulation element (such as a polarization grating or a polarization film). The diffractive optical element is designed for polarized light, and projects different light beams according to different polarization directions to form corresponding light spots.

[0069] The present invention is not limited to the number of light beams and light spots, and may be two groups of light beams and two groups of light spots, or four groups of light beams and four groups of light spots, or other numbers, all of which are within the protection scope of the present invention.

[0070] According to a preferred embodiment of the present invention, the received light is further divided into at least two groups of beams by a beam splitter element disposed between the light emitting device and the diffractive optical element, the number of which corresponds to the at least two groups of beams, and the diffractive optical element is configured to receive the at least two groups of beams, and modulate and project the at least two groups of beams. The beam splitter element may be a polarization beam splitter element, configured to divide the received light into at least two groups of polarized light with different polarization directions. The beam splitter element may also be a non-polarization beam splitter.

[0071] According to a preferred embodiment of the present invention, the diffractive optical element is configured to modulate incident light with different polarization directions to form at least two groups of distinctive light spot patterns on the target surface.

[0072] Fig.10An electronic device 500 according to another embodiment of the present invention is shown, comprising: the beam splitting optical module 100 / 200 / 300 as described above, a camera 501 and a processing device 502. The electronic device 500 can be various types of electronic devices such as a mobile phone, a PAD, a laptop computer, a desktop computer, a monitoring system, etc. After the beam splitting optical module projects at least two groups of light spots on the target surface, the camera 501 collects the pattern formed by the light spots and hands it over to the processing device 502 for processing and analysis. The embodiments of the present invention can have various uses, such as for applications such as unlocking, face recognition, and monitoring by collecting light spot patterns after projecting structured light. It can be a polarized receiver or an ordinary receiver. If it is an ordinary receiver, the images can be simply collected together for processing. If it is a polarized receiver, the physical polarization property information is recorded together as a more accurate three-dimensional sensor.

[0073] Fig.11 FIG. 6 shows a method 600 for manufacturing a beam splitting optical module according to an embodiment of the present invention. Fig.11 As shown, in step S601, a substrate of an optical module is provided; in step S602, a light-emitting device is prepared on the substrate; in step S603, a diffractive optical element is formed on the light emission path of the light-emitting device, and the diffractive optical element is configured to modulate the incident light to project at least two groups of light beams and form at least two groups of light spots of corresponding numbers on the target surface, and the at least two groups of light beams have different polarization directions and / or different optical paths from the light-emitting device to the target surface.

[0074] According to one embodiment of the present invention, the manufacturing method 600 also includes: setting a polarization modulation element between the light-emitting device and the diffractive optical element, the polarization modulation element is configured to modulate the light emitted by the light-emitting device into at least two groups of polarized lights with different polarization directions, the number corresponding to the at least two groups of light beams, the diffractive optical element is configured to modulate the at least two groups of polarized lights to project the at least two groups of light beams, wherein the polarization modulation element is preferably a polarization grating and / or a polarizing film, and the light-emitting device is preferably a vertical cavity surface emitting laser or an edge emitting laser or an LED.

[0075] According to one embodiment of the present invention, the manufacturing method 600 also includes: a beam splitter element is arranged between the light emitting device and the diffractive optical element, and the beam splitter element is configured to split the received light into at least two groups of beams of light, the number of which corresponds to the at least two groups of beams of light, and the diffractive optical element is configured to receive the at least two groups of beams of light, and modulate and project the at least two groups of beams of light.

[0076] Fig.12 A beam splitting optical module 700 according to another embodiment of the present invention is shown. Figure 8The beam splitting optical module 300 shown is similar. Figure 8 The beam splitting optical module 300, Fig.12 The beam splitting optical module 700 includes multiple beam splitting surfaces, such as beam splitting surface 1, beam splitting surface 2, beam splitting surface 3, beam splitting surface 4 or more beam splitting surfaces shown in the figure. By setting multiple beam splitting surfaces, the light beam emitted by the light source can be divided into multiple groups of light beams with different optical paths. Fig.12 As shown in the figure, there are four groups of light beams, which are incident on different areas on the surface of the diffractive optical element. Accordingly, the different areas on the surface of the diffractive optical element have different microstructures according to the different optical paths of the incident light beams, and the incident light beams are modulated accordingly to form different focal lengths, project different groups of light beams and form a corresponding number of light spots on the target surface. Alternatively, each beam splitting surface can be a polarization beam splitting surface, for example, splitting the light beam emitted by the light source into polarized lights of multiple polarization directions. In this case, it is not necessary for the surface of the diffractive optical element to have different microstructures in different areas, such as Figure 1 and Figure 2 As shown in the case shown, light beams with different polarization directions are incident on the diffractive optical element, and the diffractive optical element will be modulated accordingly according to the polarization direction of the incident light. By adding multiple beam splitting surfaces, each light beam corresponds to a different focal length, and the combination of long and short focal lengths can increase the coverage range.

[0077] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

[0078] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A beam splitting optical module, comprising: A light emitting device, wherein the light emitting device comprises a polarization modulation element, so as to modulate light from a single point light source into polarized light in multiple directions; a diffractive optical element, the diffractive optical element being arranged on a light emitting path of the light emitting device and configured to modulate the incident light to project at least two groups of light beams and to form at least two groups of light spots of corresponding numbers on a target surface, wherein the polarization directions of the at least two groups of light beams are different from each other; and A polarization beam splitter element is arranged between the light emitting device and the diffractive optical element, and is configured to split the received light into at least two groups of polarized light with different polarization directions, the number of which corresponds to the at least two groups of light beams, and the diffractive optical element is configured to receive the at least two groups of polarized light, and modulate and project the at least two groups of light beams.

2. The beam splitting optical module according to claim 1, characterized in that: The polarization modulation element is configured to modulate the light emitted by the light-emitting device into at least two groups of polarized light with different polarization directions, the number of which corresponds to the at least two groups of light beams, and the diffraction optical element is configured to modulate the at least two groups of polarized light to project the at least two groups of light beams, wherein the polarization modulation element is a polarization grating or a polarizing film, and the light-emitting device also includes a vertical cavity surface emitting laser or an edge emitting laser or an LED.

3. The beam splitting optical module according to claim 1 or 2, characterized in that: The diffractive optical element is configured to project two groups of light beams and form two groups of light spots on the target surface, or to project four groups of light beams and form four groups of light spots on the target surface.

4. The beam splitting optical module according to claim 1 or 2, characterized in that: The diffractive optical element has at least two regions corresponding to the number of the light spots, and the microscopic structures on the at least two regions are different, and are respectively configured to modulate light beams with different optical paths incident thereon.

5. The beam splitting optical module according to claim 1 or 2, characterized in that: The diffractive optical element is configured to modulate incident light with different polarization directions to form at least two sets of distinctive light spot patterns on a target surface.

6. A light modulation method, comprising: Receiving light emitted by a light emitting device, wherein the light emitting device includes a polarization modulation element, so as to modulate light from a single point light source into light polarized in multiple directions; The light from the light emitting device is modulated by a diffractive optical element to project at least two groups of light beams and form at least two groups of light spots with corresponding numbers on a target surface. wherein the polarization directions of the at least two groups of light beams are different from each other; and By means of a polarization beam splitter element disposed between the light emitting device and the diffractive optical element, the received light is split into at least two groups of polarized light with different polarization directions, the number of which corresponds to the at least two groups of light beams. The diffractive optical element is configured to receive the at least two groups of polarized light, and modulate and project the at least two groups of light beams.

7. The light modulation method according to claim 6, characterized in that: The polarization modulation element is configured to modulate the light emitted by the light-emitting device into at least two groups of polarized light with different polarization directions, the number of which corresponds to the at least two groups of light beams, and the diffraction optical element is configured to modulate the at least two groups of polarized light to project the at least two groups of light beams, wherein the polarization modulation element is a polarization grating or a polarizing film, and the light-emitting device also includes a vertical cavity surface emitting laser or an edge emitting laser or an LED.

8. The light modulation method according to claim 6 or 7, characterized in that: The diffractive optical element is configured to project two groups of light beams and form two groups of light spots on the target surface, or to project four groups of light beams and form four groups of light spots on the target surface.

9. The optical modulation method according to any one of claims 6 to 8, characterized in that: The diffractive optical element is configured to modulate incident light with different polarization directions to form at least two sets of distinctive light spot patterns on a target surface.

10. An electronic device, comprising: The beam splitting optical module as claimed in any one of claims 1 to 5; A camera, wherein the camera collects a pattern formed by the light spot; and A processing device receives the pattern captured by the camera and processes the pattern.

11. A method for manufacturing a beam splitting optical module, comprising: Providing a substrate for an optical module; A light-emitting device is prepared on the substrate, wherein the light-emitting device includes a polarization modulation element, so as to modulate light from a single point light source into polarized light in multiple directions; forming a diffractive optical element on the light emitting path of the light emitting device, wherein the diffractive optical element is configured to modulate the incident light to project at least two groups of light beams and form at least two groups of light spots of corresponding numbers on a target surface, wherein the polarization directions of the at least two groups of light beams are different from each other; and A polarization beam splitter element is arranged between the light emitting device and the diffractive optical element, and the polarization beam splitter element is configured to split the received light into at least two groups of polarized light with different polarization directions, the number of which corresponds to the at least two groups of light beams, and the diffractive optical element is configured to receive the at least two groups of polarized light, and modulate and project the at least two groups of light beams.

12. The manufacturing method according to claim 11, characterized in that: The polarization modulation element is configured to modulate the light emitted by the light-emitting device into at least two groups of polarized light with different polarization directions, the number of which corresponds to the at least two groups of light beams, and the diffraction optical element is configured to modulate the at least two groups of polarized light to project the at least two groups of light beams, wherein the polarization modulation element is a polarization grating or a polarizing film, and the light-emitting device also includes a vertical cavity surface emitting laser or an edge emitting laser or an LED.

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