A metasurface design method, metasurface, projection device and sweeping robot

Abstract

The application relates to the technical field of optics, in particular to a metasurface design method, a metasurface, a projection device and a sweeping robot. The metasurface design method comprises the following steps: obtaining a preset target light source pattern, determining the required phase difference of microstructures in the metasurface by using the preset target light source pattern; determining the shape and material of the microstructures according to the wave band of the light source and the phase difference; establishing a color card mapping table of the microstructure parameters, the wave band of the light source, the phase of the light beam after being shaped by the metasurface and the transmittance of the metasurface based on the shape and material of the microstructures; and selecting corresponding microstructure parameters from the color card mapping table according to the phase difference to determine the microstructures of the metasurface, so that the target metasurface is obtained. The embodiment can realize flexible control of a complex pattern when the light source is regulated.

Description

Technical Field

[0001] This application relates to the field of optical technology, and in particular to a metasurface design method, metasurface, projection device, and sweeping robot. Background Technology

[0002] In existing technologies, depth cameras based on indirect time-of-flight technology typically use laser projection devices to emit a uniform floodlight beam towards the target scene. However, when such depth cameras are applied to specific scenarios, such as ground-based mobile robots, the light emitted near the fixed side is easily blocked and reflected by the ground, tabletops, or other working surfaces. This can lead to excessively large reflected light signals received by the image sensor, resulting in overexposure and inaccurate 3D information of the target measured by the depth camera, thus reducing overall performance. Therefore, it is necessary to shape the floodlight beam using optical devices such as prism systems and diffraction gratings. However, these optical devices have limitations in terms of the complexity and flexibility of beam shaping. Summary of the Invention

[0003] In view of this, embodiments of this application provide a metasurface design method, a metasurface, a projection device, and a sweeping robot, which can solve at least one technical problem in the related art.

[0004] In a first aspect, one embodiment of this application provides a metasurface design method, comprising: acquiring a preset target light source pattern; determining the phase difference required for the microstructure in the metasurface using the preset target light source pattern; determining the shape and material of the microstructure based on the wavelength of the light source and the phase difference; establishing a color chart mapping table of microstructure parameters, light source wavelength, phase of the beam after metasurface shaping, and metasurface transmittance based on the shape and material of the microstructure; and selecting corresponding microstructure parameters from the color chart mapping table according to the phase difference to determine the microstructure of the metasurface, thereby obtaining the target metasurface. This embodiment of the metasurface design method allows for flexible control of complex patterns when adjusting the light source.

[0005] Secondly, one embodiment of this application provides a metasurface obtained according to the metasurface design method described in the first aspect embodiment. The metasurface provided in this embodiment has a simple structure, is easy to process and manufacture, facilitates the thinning of devices, and has effective phase modulation function and transmission efficiency.

[0006] Thirdly, one embodiment of this application provides a projection device, including a light source and the metasurface described in the second aspect embodiment. The metasurface is located in the emission direction of the light source, and the light beam emitted by the light source is shaped by the metasurface to form an illumination light field with a target light source pattern.

[0007] Fourthly, one embodiment of this application provides a depth camera, including the projection device, receiving device, and processing device described in the third aspect embodiment. The receiving device includes a receiving optical element and an image sensor. The projection device is used to emit an illumination light field with a target light source pattern toward a target area. The receiving optical element is used to receive a beam of light from at least a portion of the illumination light field reflected back from the target area and guide it onto the image sensor for imaging. The processing device is used to perform depth calculation on the image generated by the image sensor to obtain depth information of the target area.

[0008] Fifthly, one embodiment of this application provides a sweeping robot, including a sweeping robot body and a depth module. The depth module includes a receiving device, a processing device, and a projection device as described in the third aspect embodiment. The projection device is used to emit light signals to a target scene, the receiving device is used to collect light signals reflected back from the target scene and transmit them to the processing device, and the processing device is used to perform depth calculations based on the received reflected light signals to obtain depth information of the target scene, and use the depth information of the target scene to control the movement of the sweeping robot body.

[0009] In a sixth aspect, one embodiment of this application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the metasurface design method as described in the first aspect embodiment.

[0010] In a seventh aspect, one embodiment of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the metasurface design method as described in the first aspect embodiment.

[0011] Eighthly, one embodiment of this application provides a computer program product that, when run on an electronic device, causes the electronic device to perform the metasurface design method as described in the first aspect embodiment.

[0012] It should be understood that the beneficial effects of the third to eighth aspects can be found in the relevant descriptions of the embodiments of the first and second aspects, and will not be repeated here. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1This is a schematic diagram of the structure of a sweeping robot provided in one embodiment of this application;

[0015] Figure 2 This is a schematic diagram of the structure of a depth module applied in a robotic vacuum cleaner according to an embodiment of this application;

[0016] Figure 3 This is a schematic diagram illustrating the implementation process of a metasurface design method provided in an embodiment of this application;

[0017] Figure 4 This is a schematic diagram of step S110 in a metasurface design method provided in an embodiment of this application;

[0018] Figure 5 This is a schematic diagram of the structure of a metasurface provided in one embodiment of this application;

[0019] Figure 6 This is a schematic diagram of a color chart mapping table provided in one embodiment of this application;

[0020] Figure 7 This is a schematic diagram illustrating the relationship between radius and transmittance when the height is kept constant, according to an embodiment of this application.

[0021] Figure 8 This is a schematic diagram illustrating the relationship between the radius and phase difference when the height is a constant, according to an embodiment of this application.

[0022] Figure 9 This is a schematic diagram of the structure of a projection device provided in one embodiment of this application;

[0023] Figure 10 This is a schematic diagram of the structure of an imaging device provided in one embodiment of this application;

[0024] Figure 11 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0025] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0026] The term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items, as well as all possible combinations, and includes such combinations.

[0027] The terms "one embodiment" or "some embodiments" described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0028] Furthermore, in the description of this application, "a plurality of" means two or more. The terms "first" and "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0029] To illustrate the technical solution described in this application, specific embodiments are provided below.

[0030] Figure 1 This is a schematic diagram of a robotic vacuum cleaner according to this application. The robotic vacuum cleaner includes a main body and a depth module embedded in the side of the main body. The depth module provides depth information of the target scene to control the movement of the robotic vacuum cleaner. In one embodiment, such as... Figure 2 As shown, the depth module includes a projection device 11, a receiving device 12, and a processing device 13. The projection device 11 is used to emit light signals to the target scene, the receiving device 12 is used to collect the light signals reflected back from the target scene and transmit them to the processing device 13, and the processing device 13 is used to perform depth calculation based on the received reflected light signals to obtain the depth information of the target scene, and use the depth information of the target scene to control the movement of the sweeping robot body.

[0031] In one embodiment, the projection device 11 includes a light source 111, a beam modulator 112, and a light source driver (not shown). The light source 111 can be a light-emitting diode (LED), an edge-emitting laser (EEL), a vertical-cavity surface-emitting laser (VCSEL), or an array of multiple light sources. The light beam emitted by the light source can be visible light, infrared light, ultraviolet light, etc. Under the control of the light source driver (which can be further controlled by the processing device 13), the light source 111 emits a light beam. For example, in one embodiment, the amplitude of the emitted light beam is modulated under control to emit a pulsed beam, a square wave beam, a sine wave beam, etc., which can be used in indirect time-of-flight (TOF) measurements. It is understood that a portion of the processing device 13 or a sub-circuit existing independently of the processing device 13 can be used to control the emission of the relevant light beam from the light source 111, such as a pulse signal generator.

[0032] The beam modulator 112 receives the beam from the light source 111 and emits a spatially modulated beam, such as a floodlight or a patterned beam. Existing beam modulators 112 are typically prism systems or diffraction gratings. When the depth module, including the projection device 11 and the receiving device 12, is located on the fixed side of the robotic vacuum cleaner, if the projection device 11 uses an existing beam modulator 112 to shape the floodlight, the existing beam modulator has limitations in terms of beam shaping complexity and flexibility. Furthermore, it is easily blocked and reflected by the ground, tabletop, or other working surfaces. This results in an excessively large reflected light signal received by the receiving device 12, leading to overexposure and inaccurate depth information of the target scene. This reduces the performance of the robotic vacuum cleaner and results in a poor user experience.

[0033] Therefore, this application provides a metasurface to replace the prism system, diffraction grating, etc., used in the existing beam modulator 112. This application also provides a metasurface design method. The metasurface structure obtained by this method is simple, easy to manufacture, and has effective phase modulation and transmission efficiency. In some embodiments, when the metasurface obtained by this method is used to control the floodlight source required for the depth module, flexible control of complex floodlight patterns can be achieved. As a non-limiting example, when the metasurface is applied to the depth module of a robotic vacuum cleaner, it can solve the overexposure phenomenon generated during the measurement process of the depth module and project complex light source patterns of different brightness into different areas of a complex scene.

[0034] In some embodiments, the receiving device 12 includes an image sensor 121, a lens unit 122, and may also include a filter (not shown). The lens unit 122 receives and images at least a portion of the spatially modulated light beam reflected from the target scene onto at least a portion of the image sensor 121. The filter must be a narrowband filter that matches the wavelength of the light source to suppress background light noise in other bands. The image sensor 121 may be an image sensor composed of a charge-coupled device (CCD), a complementary metal-oxide-semiconductor (CMOS), an avalanche diode (AD), a single-photon avalanche diode (SPAD), etc.

[0035] In one embodiment, the image sensor 121 includes at least one pixel, and each pixel includes multiple taps (for storing and reading or discharging charge signals generated by incident photons under the control of a corresponding electrode), such as three taps, for reading charge signal data.

[0036] In some embodiments, the depth module may also include drive circuits, power supplies, color cameras, infrared cameras, IMUs, and other devices, which are not shown in the figure. Combinations with these devices can enable richer functions, such as 3D texture modeling and SLAM.

[0037] In one embodiment, the processing device 13 may be an independent dedicated circuit, such as a dedicated SOC chip, FPGA chip, ASIC chip, etc., which includes a CPU, memory, bus, etc. It may also include a general processing circuit, such as when the depth module is integrated into the robot vacuum cleaner, the processing circuit in the robot vacuum cleaner may be used as at least part of the processing device 13.

[0038] In some embodiments, the processing device 13 is used to provide the modulation signal (emission signal) required when the light source 111 emits laser light, and the light source emits a light beam toward the target scene under the control of the modulation signal; in addition, the processing device 13 also provides the demodulation signal (acquisition signal) of the taps in each pixel of the image sensor 121, and the taps acquire the charge signal generated by the light beam reflected back from the target scene under the control of the demodulation signal. Generally, in addition to the reflected light beam from the target scene, there are also some background light, interference light and other light beams; the processing device 13 can also provide auxiliary monitoring signals, such as temperature sensing, overcurrent, overvoltage protection, detachment protection, etc.; the processing device 13 can also be used to save the raw data acquired by each tap in the image sensor 121 and process it according to the time-of-flight measurement principle to obtain the depth information of the target scene.

[0039] Figure 3 This is a schematic diagram illustrating the implementation flow of a metasurface design method provided in an embodiment of this application. The metasurface design method may include steps S110 to S140, wherein:

[0040] S110, Obtain the preset target light source pattern, and use the preset target light source pattern to determine the phase difference required for the microstructure in the metasurface.

[0041] The preset target light source pattern is the pattern formed after the light source is emitted onto the metasurface and shaped by the metasurface. The preset target light source pattern may include multiple sub-patterns, each of which is formed by the light source being shaped by at least one microstructure in the metasurface. The preset target light source pattern can be stored in advance or generated in real time using optical design software.

[0042] As a possible implementation, when the depth module experiences overexposure during measurement or when complex light source patterns with varying brightness are required to be projected in different areas of a complex scene, a pre-designed target light source pattern that conforms to the current environment can be pre-designed based on the environment in which the depth module is located. For example, Figure 4 As shown, the upper region of the preset target light source pattern is brighter than the lower region, so that when the depth camera acquires the preset target light source pattern reflected by the target object, the obtained image is not overexposed or can measure the target scene in one go without repeating multiple times, thus obtaining accurate measurement results.

[0043] After obtaining the preset target light source pattern, the phase difference required for the microstructure in the metasurface is determined based on the preset target light source pattern. As one possible implementation, see [link to relevant documentation]. Figure 4 As shown, based on the iterative Fourier method, the relative phase distribution of a preset target light source pattern is generated, thereby determining the phase difference required for the microstructure in the metasurface based on the relative phase distribution. Figure 4 In the example shown, the target light source pattern obtained after metasurface shaping is used in time-of-flight depth measurement, so that the brightness of the illumination field projected onto the target area is higher in the upper region (i.e., the far-ground region) than in the lower region (i.e., the near-ground region). When this illumination field obtained after metasurface shaping is applied to a robotic vacuum cleaner, the light emitted from the side near the ground is less likely to be blocked and reflected by the ground, tabletop, or other working surfaces, effectively solving the problem of excessive reflected light signals collected by the receiving device and overexposure, thereby improving the accuracy of the target three-dimensional information measured by the depth module.

[0044] It should be noted that in the following embodiments or examples, the microstructure is exemplified as a cylindrical microstructure. It should be understood that the exemplary description should not be construed as a specific limitation of this application.

[0045] S120 determines the shape and material of the microstructure based on the wavelength and phase difference of the light source.

[0046] Different shapes and materials of microstructures in metasurfaces result in different responses to optical signals. After determining the preset target light source pattern, a suitable cylindrical microstructure and material are selected based on the wavelength of the emitted light beam and the phase difference required by the microstructure to obtain the first metasurface. It should be noted that this only restricts the structure and material of the metasurface; the microstructure of the first metasurface still needs to be specifically designed subsequently.

[0047] In some embodiments, such as Figure 5 As shown, the first metasurface includes a glass substrate and cylindrical microstructures disposed on the glass substrate. The cylindrical microstructures can be arranged in a certain pattern on one side surface of the glass substrate, so that when a light source passes through the metasurface, it can be shaped to obtain a floodlight with a preset target light source pattern. In this embodiment, a dielectric metasurface is used. In this embodiment, the metasurface may include multiple artificial atomic units arranged in a two-dimensional manner. The artificial atomic units may be subwavelength-scale microstructures (i.e., cylindrical microstructures) to control the propagation of light. In one implementation, the center-to-center distance of the cylindrical microstructures is 0.3 μm (unit: micrometer).

[0048] To avoid the materials used in the microstructures of the metasurface affecting the shaping effect of the light source, in some embodiments, when the light source is in the visible light band, titanium dioxide (TiO2) is preferably used as the material of the microstructure; when the light source is in the near-infrared band, silicon (Si) is preferably used as the material of the microstructure. This allows the microstructure to adapt to light sources of different wavelengths.

[0049] S130, based on the shape and material of the microstructure, establishes a color chart mapping table of microstructure parameters with the wavelength of the light source, the phase of the beam after metasurface shaping, and the transmittance of the metasurface.

[0050] Based on the shape and material of the microstructure, a first color chart mapping table is established, which maps the microstructure parameters, the wavelength of the light source, and the phase of the beam after metasurface shaping. A second color chart mapping table is also established, which maps the microstructure parameters, the wavelength of the light source, and the transmittance of the metasurface.

[0051] Given a fixed microstructure shape and material, by modifying microstructure parameters such as cylinder height and radius, metasurfaces of different specifications can be simulated. The phase and energy of the light beam after metasurface shaping are then simulated by passing the light source through these different specifications, and a corresponding color chart is established. In other words, the color chart reflects the influence of microstructure parameters (including the height and radius of the cylindrical microstructure) on phase and transmitted energy. It should be noted that comparing the luminous flux emitted by the light source with the luminous flux obtained after metasurface shaping yields the metasurface transmittance. Therefore, the color chart can be considered to reflect the influence of microstructure parameters on phase and transmittance; that is, a phase-dependent color chart and a transmittance-dependent color chart. In one possible implementation, [the text continues...] Figure 4 As shown in the example, when the wavelength of the light beam emitted by the light source is, for example, 532nm, the corresponding color chart mapping table is as follows: Figure 6 As shown, Figure 6 Figure A in the middle is a phase-dependent color chart. Figure 6 Figure B shows a color chart mapping table related to transmittance. Figure 6 Different heights and radii correspond to squares of different colors. Based on the color, the corresponding microstructure parameters can be found in the color chart corresponding to the phase or transmittance.

[0052] S140. Based on the phase difference required for the microstructure in the metasurface, select the corresponding microstructure parameters from the color chart to determine the microstructure of the metasurface and obtain the target metasurface.

[0053] Based on the phase difference required for the metasurface microstructure, a suitable microstructure with appropriate radius and height is selected from a color chart to obtain a metasurface that meets the preset specifications. Specifically, based on the phase difference required for the metasurface microstructure, suitable microstructure parameters of radius and height are selected from both a phase-dependent color chart and a transmittance-dependent color chart to obtain the target metasurface.

[0054] In this embodiment, the height and radius of the microstructure can both be variables. By combining different values, a target metasurface that meets the preset index can be obtained. Alternatively, one parameter can be a fixed value and the other parameter can be a variable to obtain a target metasurface that meets the preset index.

[0055] In one embodiment, the radius of the microstructure is preferably controlled by setting the height as a constant to obtain the target metasurface. Preferably, according to actual design requirements, a corresponding height is selected as the height of the microstructure from a transmittance-related color chart. Preferably, a height of 1.35 μm (unit: micrometer) can ensure high and stable transmittance. Figure 7 As shown. While ensuring transmittance, the required radius of the microstructure corresponding to each sub-pattern in the preset target light source pattern is determined based on the phase difference and color chart mapping table, such as... Figure 8As shown, by traversing each sub-pattern, the radius required for the microstructure corresponding to each sub-pattern is obtained, thus completing the metasurface design and obtaining the target metasurface.

[0056] One embodiment of this application also provides a metasurface, which is a metasurface obtained according to the metasurface design method provided in any of the foregoing embodiments. For details not described in this embodiment, please refer to the relevant descriptions of the foregoing metasurface design method embodiments; they will not be repeated here.

[0057] The metasurface design method provided in this application embodiment can achieve flexible control of complex patterns when adjusting the light source. The designed metasurface structure is simple, easy to process and manufacture, and conducive to the thinning of devices. It has effective phase control function and transmission efficiency.

[0058] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0059] One embodiment of this application also provides a projection device, which includes a light source and a metasurface located in the emission direction of the light source. The light source is used to emit a light beam, and the light beam emitted by the light source is shaped by the metasurface to form an illumination light field with a target light source pattern. The metasurface obtained by the design method provided in this application can reduce the size and assembly complexity of the projection device.

[0060] Specifically, the light source can be a light-emitting diode (LED), a laser diode (LD), an edge-emitting laser (EEL), a vertical-cavity surface-emitting laser (VCSEL), etc. The light source can be visible light, infrared light, ultraviolet light, etc. As can be seen from the foregoing embodiments, the wavelength of the emitted light beam is considered during the design of the metasurface.

[0061] In some embodiments, such as Figure 9 As shown, the projection device may further include a collimation system disposed between the light source and the metasurface. The light source is disposed at the light incident end of the collimation system, and the metasurface is disposed at the light emitting end of the collimation system. The light beam emitted by the light source is first collimated by the collimation system and then incident on the metasurface, and then shaped by the metasurface to form an illumination light field with the target light source pattern. Preferably, the collimation system is a collimating lens group composed of concave lenses and convex lenses. It should be understood that the exemplary description herein should not be construed as a limitation of this application. In one possible implementation, the illumination light field may be a floodlight illumination light field.

[0062] In some embodiments, the projection device may also include a driver, etc., and the light source emits a light beam outward under the control of the driver.

[0063] One embodiment of this application also provides an imaging device, such as... Figure 10 As shown, it includes a projection device and a receiving device. The projection device is used to emit an illumination light field with a target light source pattern onto a target area. The receiving device includes a receiving optical element and an image sensor. The receiving optical element is used to receive at least a portion of the light beam reflected back from the target area and guide it onto the sensor for imaging. Figure 10 In the example described, the receiving optical element is a focusing lens.

[0064] In some embodiments, the imaging device may further include a processing unit for calculating depth information of the target region based on the reflected light beam. As a possible implementation, the imaging device may be a depth camera, or it may be... Figure 1 The image shows a depth module used in a robotic vacuum cleaner.

[0065] In some embodiments, the processing device may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0066] One embodiment of this application also provides an electronic device, such as... Figure 11 As shown, the electronic device may include one or more processors 1100 ( Figure 11 (Only one is shown in the image), memory 1101, and computer program 1102 stored in memory 1101 and executable on one or more processors 1100, such as a program for designing metasurfaces. When one or more processors 1100 execute computer program 1102, they can implement various steps in the metasurface design method embodiments.

[0067] Those skilled in the art will understand that Figure 11 This is merely an example of an electronic device and does not constitute a limitation on electronic devices. Electronic devices may include more or fewer components than illustrated, or combinations of certain components, or different components. For example, electronic devices may also include input / output devices, network access devices, buses, etc.

[0068] In one embodiment, the processor 1100 may be a CPU, or other general-purpose processors, DSPs, ASICs, FPGAs, or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0069] In one embodiment, memory 1101 may be an internal storage unit of an electronic device, such as a hard disk or RAM. Memory 1101 may also be an external storage device of the electronic device, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc. Furthermore, memory 1101 may include both internal and external storage units. Memory 1101 is used to store computer programs and other programs and data required by the electronic device. Memory 1101 can also be used to temporarily store data that has been output or will be output.

[0070] An embodiment of this application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, can implement the various steps in the metasurface design method embodiment.

[0071] One embodiment of this application provides a computer program product that, when run on an electronic device, enables the electronic device to implement the various steps in the metasurface design method embodiment.

[0072] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0073] Those skilled in the art will recognize that the algorithm steps described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0074] Based on this understanding, all or part of the processes in the above method embodiments of this application can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the above method embodiments. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0075] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A metasurface design method, characterized in that, The method comprises: acquiring a preset target light source pattern, and determining a required phase difference of a microstructure in the metasurface by using the preset target light source pattern; determining a shape and a material of the microstructure according to a wave band of the light source and the phase difference; establishing a first color card mapping table of a microstructure parameter, the wave band of the light source and a phase of a light beam reshaped by the metasurface, and establishing a second color card mapping table of the microstructure parameter, the wave band of the light source and a metasurface transmittance based on the shape and the material of the microstructure; the microstructure parameter comprises a height and a radius; selecting a corresponding height as the height of the microstructure in the second color card mapping table according to the metasurface transmittance, and determining the radius of the microstructure according to the phase difference and the first color card mapping table with the height as a constant value; determining the microstructure of the metasurface according to the microstructure parameter, and obtaining the metasurface.

2. The metasurface design method of claim 1, wherein, The microstructure is a cylindrical microstructure.

3. The metasurface design method of claim 2, wherein, When the light source is a visible light wave band, the material of the microstructure is TiO2; and when the wave band of the light source is a near-infrared wave band, the material of the microstructure is Si.

4. A metasurface characterized in that, The metasurface comprises a glass substrate and the microstructure on the glass substrate, and is obtained according to the metasurface design method in any one of claims 1 to 3.

5. A projection device, characterized by The system comprises a light source and the metasurface in claim 4, the metasurface is located in an emission direction of the light source, and the light beam emitted by the light source forms an illumination light field with the target light source pattern after being reshaped by the metasurface.

6. A depth camera characterized by, The system comprises the projection device in claim 5, a receiving device and a processing device, wherein the receiving device comprises a receiving optical element and an image sensor, the projection device is used to emit an illumination light field with the target light source pattern to a target area, the receiving optical element is used to receive a light beam of at least part of the illumination light field reflected back by the target area and direct the light beam to the image sensor to form an image, and the processing device is used to perform depth calculation on the image generated by the image sensor to obtain depth information of the target area.

7. A robot vacuum cleaner comprising a vacuum cleaner body and a depth module, characterized in that, The depth module comprises the receiving device, the processing device and the projection device in claim 5, wherein: the projection device is used to emit an illumination light field with a target light source pattern to a target scene; the receiving device is used to collect a light signal reflected back by the target scene and transmit the light signal to the processing device; the processing device is used to perform depth calculation on the received reflected light signal to obtain depth information of the target scene, and control a motion of the sweeping machine body by using the depth information of the target scene.

8. An electronic device, comprising: The computer readable storage medium stores a computer program, and the computer program is executed by the processor to implement the metasurface design method in any one of claims 1 to 3.

9. A computer-readable storage medium, characterized in that, ​

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