Pattern projection and detection using flat optics

Abstract

The optical pattern projection device includes a light-emitting element or array of light-emitting elements, and one or more flat optics layers configured to project and split a light beam from the light-emitting elements to generate a projected optical pattern, each containing multiple subpatterns corresponding to one of the light-emitting elements. The flat optics layer may include one optical metasurface containing superimposed beam shaping and / or projection phase profiles and beam splitting phase profiles. Alternatively, the flat optics layer may include two optical metasurfaces, each containing an optical shaping and / or projection phase profile, which jointly generate a linear relationship between the position of the light-emitting element and the corresponding beam projection angle, and one or both of these metasurfaces further contain superimposed beam splitting phase profiles. The optical shaping and / or projection phase profiles may have similar functions to a microlens array. Structured optical cameras combining optical pattern projection and detection are also provided.

Description

Technical Field

[0001] Background of the Invention The present invention relates to flat optics and their applications in optical and photonic systems.

Background Art

[0002] The generation and detection of optical patterns capture changes in the light intensity, phase, or polarization of an illuminated scene, which is extremely important for application fields such as 3D sensing, medical image generation, automation, lighting, displays, Lidar (light detection and ranging), optical computing, environmental monitoring, etc. The state-of-the-art pattern generation optical systems typically rely on refractive and / or diffractive optical elements (DOEs) for light shaping and projection. What is obtained by such traditional optical methods is usually a complex, multi-element assembly, with suboptimal pattern quality, limited field of view (less than 90°), low efficiency, and a bulky form factor.

[0003] In the optical system described in U.S. Patent Application Publication No. 20210044748 (see FIGS. 13A and 13B), a metasurface is used to modulate the beam emitted by an array of light-emitting elements to generate a 2D or 3D optical pattern, dot array or cloud, image, hologram, or a pattern with different polarization and / or spectral characteristics.

Summary of the Invention

Means for Solving the Problems

[0004] Summary of the Invention The present invention relates to an optical pattern generation architecture based on flat optics that substantially eliminates one or more problems arising from the limitations and drawbacks of the related art.

[0005] Embodiments of the present invention provide optical projection, pattern generation, and detection architectures using metasurface flat optics. These architectures offer higher performance, a smaller form factor, and greater functionality compared to traditional optical methods. This optical architecture can be used in a variety of optical systems, including sensing, structured optical imaging, illumination, display, LiDAR, and computing.

[0006] Further features and advantages of the present invention are described in the following description, and some will become apparent from the description or from the practice of the invention. The objectives and other advantages of the present invention are realized and achieved by the structure specifically shown in the description, the claims, and the accompanying drawings.

[0007] To achieve the above objectives, the present invention provides an optical pattern projection apparatus comprising: one or more light-emitting elements; and a first optical metasurface coupled to the one or more light-emitting elements and configured to project, reshape, and / or split a light beam generated by the one or more light-emitting elements to generate a projected light pattern, wherein the first metasurface layer comprises at least two superimposed phase profiles performing different functions from each other, and each of the at least two phase profiles is configured to modulate, collimate, focus, diverge, deflect, shape, split, diffract, or diffuse a light beam from the one or more light-emitting elements.

[0008] In some embodiments, the superimposed phase profiles are configured to split or diffract the light so as to spatially or angularly disperse the light beam from each of one or more light-emitting devices into multiple channels.

[0009] The apparatus may further include a second optical metasurface spaced apart from the first optical metasurface, the second optical metasurface including an optical shaping and / or projection phase profile configured to collimate, focus, and / or deflect light beams from one or more light-emitting elements, and the first and second optical metasurfaces cooperate with each other to produce a predetermined relationship between the position or optical characteristics of the light-emitting elements and the corresponding beam projection angle. In some embodiments, the predetermined relationship is a linear relationship between the position of the light-emitting elements and the beam projection angle.

[0010] In another embodiment, the present invention provides an optical pattern projection apparatus comprising: an array of light-emitting elements including a plurality of light-emitting elements; and one or more flat optics layers configured to project and divide a light beam generated by the plurality of light-emitting elements to generate a projected optical pattern, wherein the projected optical pattern comprises a plurality of subpatterns, each corresponding to one of the light-emitting elements, and the subpatterns are identical in shape, offset from each other, and overlap each other.

[0011] In another embodiment, the present invention provides an optical pattern projection apparatus comprising: an array of light-emitting elements including a plurality of light-emitting elements; and a flat optics layer coupled to the light-emitting element array and configured to project, reshape, and / or split light beams generated by the plurality of light-emitting elements to generate a projected light pattern, wherein the projected light pattern comprises a plurality of subpatterns, each corresponding to one of the light-emitting elements, and the flat optics layer includes a phase profile for beam collimation and projection configured to combine different regions of the flat optics with light beams from different light-emitting elements, and a beam splitting phase profile configured to spatially disperse the light beams from each light-emitting element into a plurality of channels, thereby providing an optical pattern projection apparatus including a superimposed phase profile.

[0012] In another embodiment, the present invention provides an optical pattern projection apparatus comprising: an array of light-emitting elements including one or more light-emitting elements; and a single flat optics layer coupled to the light-emitting element or array of light-emitting elements and configured to project, reshape, and / or divide a light beam generated by the light-emitting element or array of light-emitting elements to generate a projected light pattern.

[0013] In another embodiment, the present invention provides an optical pattern projection apparatus comprising: an array of light-emitting elements including one or more light-emitting elements; and two flat optics layers spaced apart from each other and having the same size, configured to project, reshape, and / or divide a light beam generated by the light-emitting elements or the plurality of light-emitting elements to generate a projected light pattern, wherein the projected light pattern comprises a plurality of subpatterns, each corresponding to one of the light-emitting elements.

[0014] In another embodiment, the present invention provides an optical pattern projection apparatus comprising: an array of light-emitting elements including one or more light-emitting elements; and two optical metasurfaces spaced apart from each other and configured to project, reshape, and / or split light beams generated by the light-emitting elements or the plurality of light-emitting elements to generate a projected optical pattern, wherein the projected optical pattern comprises a plurality of subpatterns, each corresponding to one of the light-emitting elements; each of the two optical metasurfaces includes an optical shaping, projection, and / or splitting phase profile configured to collimate, focus, and / or deflect light beams from the light-emitting elements or the plurality of light-emitting elements; the two optical metasurfaces cooperate with each other to produce a predetermined relationship between the position or optical properties of the light-emitting elements and the beam projection angle; and at least one of the two optical metasurfaces further includes a superimposed beam splitting phase profile configured to spatially disperse the light beams from each light-emitting element into a plurality of channels.

[0015] In another embodiment, the present invention provides an optical pattern projection detection device that includes any of the above-described optical pattern projection devices, and further includes an optical pattern detection device that includes another optical metasurface and a light receiving device coupled to the other optical metasurface.

[0016] Both the above general description and the following detailed description are illustrative and intended to further elaborate on the claimed invention. [Brief explanation of the drawing]

[0017] Brief explanation of the drawing [Figure 1A] An example of a light pattern generation architecture using flat optics according to an embodiment of the present invention is schematically shown. [Figure 1B] An example of a light pattern generation architecture using flat optics according to an embodiment of the present invention is schematically shown. [Figure 1C] An example of a light pattern generated by the light pattern generation architecture according to an embodiment of the present invention is shown. [Figure 1D] An example of a light pattern generated by the light pattern generation architecture according to an embodiment of the present invention is shown. [Figure 1E] An example of a light pattern generated by the light pattern generation architecture according to an embodiment of the present invention is shown. [Figure 2A] An exemplary light pattern generation architecture according to one embodiment of the present invention, which generates a light pattern similar to that shown in Figure 1C, is shown. [Figure 2B] An exemplary light pattern generation architecture according to one embodiment of the present invention, which generates a light pattern similar to that shown in Figure 1C, is shown. [Figure 2C] An exemplary light pattern generation architecture according to one embodiment of the present invention, which generates a light pattern similar to that shown in Figure 1C, is shown. [Figure 2D]An exemplary optical pattern generation architecture according to an embodiment of the present invention that generates an optical pattern similar to that shown in FIG. 1C is shown. [Figure 3A] The light emitting element array and dot projection characteristics of an optical pattern generation architecture similar to that shown in FIGS. 2A - 2D are shown. [Figure 3B] The light emitting element array and dot projection characteristics of an optical pattern generation architecture similar to that shown in FIGS. 2A - 2D are shown. [Figure 3C] The light emitting element array and dot projection characteristics of an optical pattern generation architecture similar to that shown in FIGS. 2A - 2D are shown. [Figure 3D] The light emitting element array and dot projection characteristics of an optical pattern generation architecture similar to that shown in FIGS. 2A - 2D are shown. [Figure 3E] The light emitting element array and dot projection characteristics of an optical pattern generation architecture similar to that shown in FIGS. 2A - 2D are shown. [Figure 4A] The light emitting element array and dot projection characteristics of another optical pattern generation architecture similar to that shown in FIGS. 2A - 2D are shown. [Figure 4B] The light emitting element array and dot projection characteristics of another optical pattern generation architecture similar to that shown in FIGS. 2A - 2D are shown. [Figure 4C] The light emitting element array and dot projection characteristics of another optical pattern generation architecture similar to that shown in FIGS. 2A - 2D are shown. [Figure 4D] The light emitting element array and dot projection characteristics of another optical pattern generation architecture similar to that shown in FIGS. 2A - 2D are shown. [Figure 4E] The light emitting element array and dot projection characteristics of another optical pattern generation architecture similar to that shown in FIGS. 2A - 2D are shown. [Figure 5A] An exemplary optical pattern generation architecture according to an embodiment of the present invention that generates an optical pattern similar to that shown in FIG. 1D is shown. [Figure 5B]An exemplary light pattern generation architecture according to an embodiment of the present invention is shown, which generates a light pattern similar to that shown in Figure 1D. [Figure 5C] An exemplary light pattern generation architecture according to an embodiment of the present invention is shown, which generates a light pattern similar to that shown in Figure 1D. [Figure 5D] An exemplary light pattern generation architecture according to an embodiment of the present invention is shown, which generates a light pattern similar to that shown in Figure 1D. [Figure 6A] Figures 5A to 5D show the light-emitting element arrays and dot projection characteristics of other optical pattern generation architectures similar to those shown. [Figure 6B] Figures 5A to 5D show the light-emitting element arrays and dot projection characteristics of other optical pattern generation architectures similar to those shown. [Figure 6C] Figures 5A to 5D show the light-emitting element arrays and dot projection characteristics of other optical pattern generation architectures similar to those shown. [Figure 6D] Figures 5A to 5D show the light-emitting element arrays and dot projection characteristics of other optical pattern generation architectures similar to those shown. [Figure 6E] Figures 5A to 5D show the light-emitting element arrays and dot projection characteristics of other optical pattern generation architectures similar to those shown. [Figure 7A] An exemplary optical pattern generation architecture according to another embodiment of the present invention is shown. [Figure 7B] An exemplary optical pattern generation architecture according to another embodiment of the present invention is shown. [Figure 8] A schematic diagram of a structured optical camera combining a flat optics-based pattern projector and a flat optics-based image sensor, according to one embodiment of the present invention, is shown. [Figure 9A] A schematic diagram of a multilayer flat optics architecture according to one embodiment of the present invention is shown. [Figure 9B] A schematic diagram of a multilayer flat optics architecture according to one embodiment of the present invention is shown. [Figure 9C] A schematic diagram of a multilayer flat optics architecture according to one embodiment of the present invention is shown. [Figure 9D] A schematic diagram of a multilayer flat optics architecture according to one embodiment of the present invention is shown. [Figure 10A] A schematic representation of a multilayer flat optics architecture according to another embodiment of the present invention is shown. [Figure 10B] The light distribution generated by the structure shown in Figure 10A is shown. [Figure 10C] This shows the light distribution generated by a single-layer flat optics. [Modes for carrying out the invention]

[0018] Detailed description of the invention Embodiments of the present invention provide pattern projection and detection optical architectures, systems, and designs using flat optics (e.g., metasurface optics, metamaterials, subwavelength optics, etc.). As schematically shown in Figures 1A and 1B, an exemplary pattern generation system includes the following components: a light-emitting element array 101 containing one or more light-emitting elements, and one or more flat optics components (FOs) 102 coupled to the light-emitting element array. The flat optics 102 (which may consist of one or more elements) are designed to provide beam projection, shaping, splitting, and / or deflection functions. The flat optics 102 can modulate the phase, intensity, and / or deflection of a beam or beam array emitted by the light-emitting element array 101.

[0019] For example, the flat optics 102 may be a metasurface including superimposed phase profiles that include optical shaping and / or projection and beam splitting functions for generating a desired pattern. The optical shaping and / or projection phase profile may be designed to collimate, focus, and / or deflect light from a light-emitting element (e.g., to generate a dot array or pattern from a light-emitting element array) or to provide other wavefront modulation functions. The beam splitting phase profile further functions to spatially disperse the projected light into multiple channels, for example, to generate multiple dot arrays or multiple projection patterns. In another example, the metasurface 102 includes two or more superimposed phase profiles that perform different functions from one another, and each phase profile is configured to modulate, collimate, focus, diverge, deflect, shape, split, diffract, diffuse, or otherwise modulate light from a light-emitting element array 101.

[0020] The pattern-generating optical system can generate any 2D or 3D pattern, including, but not limited to, arrays of dots, lines, matrices, letters, graphics, holograms, random patterns, grayscale patterns, uniform patterns, diffuse patterns, etc. Therefore, they can be used in projectors, illuminators, light diffusers, etc. Optical shaping and / or projection (e.g., acting as a lens) and beam splitting phase profiles can be superimposed on the same flat optics layer (Figure 1A) or on another flat optics layer (Figure 1B). In addition, the superimposed phase profiles can be configured to function the same or differently depending on the characteristics of the incident light (e.g., wavelength, polarization, angle of incidence, etc.). The flat optics 102 can be configured to provide different responses depending on the differences in the characteristics of the light.

[0021] The flat optics component 102 may be a metasurface containing one or more superimposed phase profiles. As an example, the flat optics component may be a metasurface containing superimposed lens phase profiles or lens and beam splitter phase profiles. The lens phase profile may collimate and / or shape and project light from the light-emitting element array 101. The beam splitter phase profile may further disperse the projection pattern into multiple channels or create multiple copies of the projection pattern, deflecting them in different directions. The beam splitting phase profile may include subregions with different k-vectors (e.g., k-vectors parallel to the flat optics plane or in-plane phase gradient patterns) that disperse the incident light beam and deflect them in different directions. This may include phase profiles similar to those of a prism and / or grating array, where each prism and / or grating deflects a portion of the incident light in a different direction (channel). This may also be similar in form to a grating that diffracts the incident light to different orders. The metasurface may be designed to control the power distribution across various diffraction orders.

[0022] The metasurface 102 is also sensitive to various properties of incident light (e.g., polarization, wavelength, angle of incidence, etc.), thereby modulating light with different properties in different ways, and redirecting it, for example, to different directions (channels), so that it can function as a beam splitter, light diffuser, or distributor. Additional beam splitting or pattern generation phase profiles can be applied to each or all of the split channels to create additional subchannels.

[0023] One embodiment of a lens phase profile is a four-phase profile. In other examples, a lens phase profile may also be defined as a polynomial expansion of spatial coordinates, a free phase profile, a discontinuous phase profile, a segmented phase profile, a superimposed phase profile, or other forms. One or more metasurfaces or lens profiles may be used. Phase profiles may be designed to control or improve the performance of an optical system, such as image generation and / or projection quality, resolution, field of view (FOV), depth of field, angle of incidence (AOI)-image height relationship, distortion, peripheral illumination ratio, uniformity, efficiency, etc.

[0024] More generally, flat optics 102 may include, but are not limited to, subwavelength optics, metasurfaces, multilayer metasurfaces, metamaterials, diffractive optical elements (DOEs, e.g., binary, multilevel, or grayscale DOEs), holographic optical elements (HOEs), wafer-level optics, microoptics, etc., or combinations thereof. One embodiment of flat optics is an optical metasurface. Also known as a subwavelength diffractive optics, an optical metasurface is an artificial medium containing a 2D array of subwavelength optical structures (commonly called metaatoms) typically positioned on a substrate. The metaatoms and substrate may be fabricated from the same or different optical materials. The metaatoms are designed to alter the phase, amplitude, and / or polarization of incident light. The metaatoms may have the same or different geometric shapes, dimensions, and orientations. Exemplary geometric shapes may include rectangles, cylinders, freeforms, or any other suitable shapes, or combinations of different shapes, etc. The lattice of metaatoms can have any suitable shape and period (e.g., square, rectangle, or hexagon). The lattice may also be periodless, with varying or random distances between adjacent metaatoms. In some examples, the gaps between adjacent metaatoms may be designed to have a constant gap distance.

[0025] The metasurface 102 may be flat, curved, or conformally integrated with its substrate. One or both sides of the substrate may be flat or curved. Both the metasurface and the substrate may be rigid, flexible, or stretchable. The geometry, dimensions, and layout of the metaatom and substrate are designed to provide the desired optical function. The metasurface is designed to operate at a single wavelength, multiple wavelengths, or across a continuous spectral range. The metasurface may be designed to provide different functions depending on the characteristics of the incident light (e.g., polarization, wavelength, angle of incidence, intensity, etc.). With appropriate configuration and materials, the metasurface can be designed for all wavelengths of light (e.g., UV, visible light, near-infrared, mid-infrared, long-wavelength infrared, etc.). The metasurface may be embedded in other optical materials. Other elements (one or an array thereof) may also be included to modulate light, such as filters (e.g., spectral, polarization, spatial, and / or angular filters), refractive and / or diffracting and / or reflective optical elements, optical modulators, liquid crystal elements, etc.

[0026] A spacer 103, made of air, glass, polymer, semiconductor, or other optical material, may be positioned between the flat optics component 102 and the light-emitting element array 101. The light-emitting element array 101, the flat optics component 102, and the spacer 103 (if any) may be mechanically bonded to each other using any suitable structure, such as an adhesive.

[0027] The flat optics architectures and designs described herein can be used for both light projection (when coupled with light-emitting elements) and detection (when coupled with detectors or photodetectors) (see Figure 8, which will be described in more detail later). When used for light projection, the light-emitting element 101 may include one or more light sources (e.g., lasers, light-emitting diodes (LEDs)) and / or optical channels (e.g., fibers, waveguides, optical couplers, etc.). When used for light detection, the photodetector may include one or more photodetectors and / or optical channels (e.g., fibers, waveguides, optical couplers, etc.). In addition to physical purposes, light-emitting elements (more commonly called optical transmitters) and photodetectors can also be non-physical, such as images and / or optical patterns generated or received, respectively, by other optical components or systems. An array of light-emitting elements may include light-emitting elements configured to emit light with the same or different characteristics, such as wavelength, polarization, beam divergence angle, order, or other beam characteristics. Additional elements (a single element or an array of elements) may also be included to modulate the emitted light, such as filters (e.g., spatial, polarization, spatial, and / or angular filters), refractive and / or diffracting and / or reflective optical elements, optical modulators, liquid crystal elements, etc. One example is a pixelate spectral filter array coupled to a light-emitting element array or a standalone filter. Another example is a pixelate polarization filter array coupled to a light-emitting element array or a standalone filter.

[0028] Light-emitting elements may have the same or different geometric shapes, dimensions, and orientations. Exemplary geometric shapes may include circles, squares, rectangles, freeforms, or any other suitable shape, or combinations of different shapes. The positions of the light-emitting elements may be any suitable layout and spacing (e.g., square, rectangle, or hexagon). The space may also be periodic, with varying or random distances between adjacent light-emitting elements. Light-emitting elements may be positioned in both planar and non-planar directions.

[0029] Figures 1C-1E show three examples of optical patterns that can be generated by the optical pattern generation architectures of Figures 1A and 1B. Each optical pattern contains multiple subpatterns, each subpattern generated by light from one of the light-emitting element arrays. Note that the circles, squares, and triangles in these figures are used to represent different subpatterns and do not represent the shape of the projected light spot. The subpatterns are the same shape but offset from each other. The subpatterns may overlap with each other (e.g., Figures 1C and 1E) or not (e.g., Figure 1D). In the optical pattern shown in Figure 1C, the light spot formed by the three light-emitting elements contains alternating dot columns. More specifically, in this example, the 1st, 4th, 7th, etc. columns are formed by the third light-emitting element, the 2nd, 5th, 8th, etc. columns are formed by the second light-emitting element, and the 3rd, 6th, 9th, etc. columns are formed by the first light-emitting element. In the light pattern shown in Figure 1D, the light spot formed by the three light-emitting elements includes three spatially spaced dot arrays, each formed by one of the three light-emitting elements. In the light pattern shown in Figure 1E, the light spot formed by the three light-emitting elements includes alternatingly arranged multi-column blocks. More specifically, in this example, the 1st, 4th, and 7th three-column blocks are formed by the third light-emitting element, the 2nd, 5th, and 8th three-column blocks are formed by the second light-emitting element, and the 3rd, 6th, and 9th three-column blocks are formed by the first light-emitting element.

[0030] An example of an optical pattern generation architecture according to an embodiment of the present invention will be described in more detail below.

[0031] In one example (Figures 2A-2D), the flat optics (e.g., a metasurface) includes superimposed phase profiles of lenses (for beam collimation and / or projection) and beam splitters to generate an alternating spot array pattern similar to that shown in Figure 1C. Figure 2A shows a ray-traced simulation of a miniature pattern generation system design realized by such flat optics. The flat optics component collimates light from the light-emitting elements, projects it in different directions, and further divides each beam into multiple channels (seven in this example, labeled 0 to +3) to generate high-density, high-quality spot projections. Figure 2B shows a ray-traced simulation of a single channel (channel 0) (note that the dashed rectangle in Figure 1C also represents channel 0). In Figures 2A and 2B, the most counterclockwise ray within each channel corresponds to the light-emitting element at the lower end of the light-emitting element array 101 in Figure 2A. Figures 2C and 2D show simulation results demonstrating the diffraction-limited beam quality of the collimated beam emitted from the light-emitting element array. The divergence angle is less than 0.13 degrees in this example. In this example, the system's design wavelength is 940 nm, but other wavelengths can also be selected.

[0032] This optical system can be configured to achieve different beam shaping functions, e.g., collimation, focusing, divergence, or other desired intensity and / or phase distributions of projection patterns (e.g., dots, lines, matrices, graphics, characters, holograms, random patterns, grayscale patterns, uniform patterns, diffuse patterns, etc.). The projected light pattern can be further manipulated by controlling the position or arrangement of the light-emitting element arrays, as well as their optical properties (e.g., polarization, wavelength, angle of incidence, etc.). Other optical elements (e.g., flat optics, refractive / reflective optics, microlens arrays, etc.) may be incorporated to further modify performance and / or possibilities.

[0033] Figures 3A–3E show the dot projection characteristics of a design similar to one of those in Figures 2A–2D. For the exemplary light-emitting element shown in Figure 3A (e.g., a VCSEL (Vertical Cavity Surface Emitting Laser) array), Figure 3B shows the far-field angular distribution of the dot array projected by a single-channel projector (without beam splitting). Each light-emitting element is collimated and projected by the projector's metaoptics to correspond to one dot in the far field. For example, if the light-emitting element array has M light-emitting elements, a total of M dots are formed using a single-channel projector. In flat optics, the beam splitting phase profile can be superimposed on the beam projection (or lens) phase profile to generate multiple dot arrays and redirect them in different directions. For example, if the beam splitting phase profile contains N×N different k-vectors, the dot array projected by a single channel can be split into N×N channels, forming N×N×M dot arrays. Thus, each light-emitting element corresponds to multiple projected dots. Figure 3C shows the far field of view angle distribution of a multi-channel projector that generates a 49-channel dot array with a 7x7 k-vector. The FOV of the multi-channel projector is further increased compared to the single-channel case (e.g., 7 times). Thus, a diagonal field of view of approximately 130° is achieved in this example. Figure 3D is a magnified view of Figure 3C and shows the diffraction-limited performance of the collimated beam with a maximum divergence angle of less than 0.13 degrees. Figure 3E shows the spatial intensity distribution of projected dots at an exemplary projection distance of 100 mm.

[0034] By changing the projected beam characteristics (e.g., divergence angle, size, intensity pattern, etc.), patterns with varying characteristics (e.g., projection distance, spot size, intensity distribution) can be generated. By controlling the position, size, density, and / or phase gradient of the entire sub-region of the flat optics' beam splitting phase profile, the beam splitting ratio between different channels of each channel, beam size, projection distance, and / or deflection angle can be changed. The k-vector can also be realized using structures of the type of 1D or 2D diffraction grating. The diffraction order generated from the grating can be used for beam splitting or redirection. The flat optics may or may not be positioned in direct contact with the light-emitting element array.

[0035] By increasing the number of k-vectors (e.g., in-plane k-vectors or phase gradient patterns), the projection pattern can be further divided and deflected, thereby increasing the number of dots and the overall FOV. For example, as shown in Figures 4A-4E, by combining the same single-channel projection phase profile with a beam-splitting phase profile having 9x9 different k-vectors, the projection dot array can be divided into 81 channels, achieving an overall dFOV of approximately 170°.

[0036] Figures 4A–4E show the dot projection characteristics of this exemplary design. Figure 4A shows an exemplary light-emitting element array (e.g., a VCSEL array). Figure 4B shows the far-field angle distribution of a dot array projected by a single-channel projector (no beam splitting). Each light-emitting element corresponds to one projection dot. Figure 4C shows the far-field angle distribution of a multi-channel projector. A beam splitting phase profile (e.g., consisting of 9 × 9 different k-vectors) is superimposed on the single-channel beam projection phase profile to generate multiple dot arrays (e.g., 81 channels per light-emitting element) and redirect them in different directions. Each light-emitting element corresponds to multiple projection dots. The FOV of the multi-channel projector is further increased compared to the single-channel case (e.g., 9 times). A diagonal FOV of approximately 170° is achieved. Figure 4D is a magnified view of Figure 4C and shows the diffraction-limited performance of a collimated beam with a maximum divergence angle of less than 0.13 degrees. Figure 4E shows the spatial intensity distribution of the projection dots at a distance of 100 mm from the projector.

[0037] In other examples (Figures 5A-5D), flat optics (e.g., metasurfaces) include superimposed phase profiles for beam collimation and / or projection (e.g., acting as wide-angle FOV lenses) and beam splitting, generating a spot array pattern similar to that shown in Figure 1D. In this case, the deflection angles between each split channel can be narrower than the single-channel FOV. Furthermore, the flat optics can be positioned in direct contact with the light-emitting array. Figure 5A shows a ray-traced simulation of a miniature pattern generation system design realized by flat optics with a shortened total track length. The flat optics component collimates light from the light-emitting elements and projects it in different directions, further splitting each beam into multiple channels to generate high-density, high-quality spot projections. Figure 5B shows a single-channel ray-traced simulation. In this example, the projected beam from each light-emitting element contains a 7x7 collimated beam, which is shown in the magnified image of the central ray. Figures 5C and 5D show simulation results demonstrating diffraction-limited beam quality for collimated beams with a divergence angle of less than approximately 0.9 degrees. In this example, the system's design wavelength is 940 nm, but other wavelengths can also be selected.

[0038] This optical system can be configured to achieve different beam shaping functions, such as collimation, focusing, divergence, or other desired intensity and / or phase distributions. The projected light pattern can be further manipulated by controlling the position or arrangement of the light-emitting element arrays, as well as their optical properties (e.g., polarization, wavelength, angle of incidence, etc.). Other optical elements (e.g., flat optics, refractive / reflective optics, microlens arrays, etc.) may be incorporated to further alter performance and / or functionality.

[0039] Figures 6A–6E show the dot projection characteristics of a design similar to those described in Figures 5A–5D. For an exemplary light-emitting element array (e.g., a VCSEL array) shown in Figure 6A, Figure 6B shows the far-field angle distribution of the dot array projected by a single-channel projector (without beam splitting). Each light-emitting element is collimated and projected by the projector flat optics, corresponding to one dot in the far field. The dFOV of the single-channel projector is approximately 120°. By superimposing beam splitting phase profiles with five k-vectors, Figure 6C shows the far-field angle distribution of a multi-channel projector, which generates a five-channel projected dot array for each light-emitting element. Each light-emitting element corresponds to multiple projected dots. In this case, the deflection angles between each splitting channel can be narrower than the single-channel FOV. Therefore, the dFOV of the multi-channel projector is similarly approximately 120°. Figure 6D is a magnified view of Figure 6C, showing the diffraction-limited performance of the collimated beam with a maximum divergence angle of less than approximately 0.9 degrees. Figure 6E shows the spatial intensity distribution of a projected dot at an exemplary projection distance of 100 mm.

[0040] By changing the projected beam characteristics (e.g., divergence angle, size, intensity pattern, etc.), patterns with different characteristics (e.g., projection distance, spot size, intensity distribution) can be generated. By controlling the position, size, density, and / or phase gradient of the entire or a portion of the beam splitting phase profile, the beam splitting ratio between different channels, beam size, projection distance, and / or the deflection angle of each channel can be changed. The flat optics may or may not be positioned in direct contact with the light-emitting element array.

[0041] The pattern generation systems shown in Figures 2A-6E can achieve a one-to-one or one-to-many correspondence between the VCSEL aperture and projection dots. This provides optimal beam quality (i.e., minimal aberration), as well as customizable FOV, projection pattern, and channel density.

[0042] In other embodiments, the metasurface phase and / or amplitude profile may be designed by superimposing yet another phase and / or amplitude modulation function. For example, superimposing one or more beam splitting profiles onto the initial beam shaping, projection, and / or splitting phase profile can generate additional channels with more dot arrays, producing a pattern similar to, for example, that shown in Figure 1E.

[0043] In other embodiments, beam projection and / or splitting metaoptics, when coupled with one or more light-emitting elements, can be used as an illuminator or light diffuser.

[0044] In yet another embodiment, the flat optics may be configured to provide a phase profile for beam collimation and projection (similar to a microlens array function), in which case different regions of the flat optics are specified to couple different light-emitting elements, as schematically shown in Figure 7A. The flat optics may further include a beam splitting phase profile superimposed on the microlens phase profile, thereby creating multiple copies of the projection pattern and generating multiple spot arrays as shown in Figure 7B.

[0045] A pattern projector, illuminator, or light diffuser may be paired with an image sensor comprising flat optics and an image sensor. Figure 8 schematically shows such a structured light camera in which a pattern projector including a light-emitting array 101 and flat optics 102 is coupled with an image sensor including other flat optics 104 and a light-receiving device 105 such as an image sensor. The image sensor may be designed to capture part or all of the scene, or only the area of ​​the scene illuminated by the pattern projector. Such a structured light camera architecture can be used for 3D sensing, structured light imaging, Lidar, computing, etc. The projector and image sensor are co-designed to allow correspondence between the light-emitting array and the image sensor array. The image sensor may be designed to capture only the area of ​​the scene illuminated by the pattern projector. The optical metasurface 104 may also be sensitive to different characteristics of incident light (e.g., polarization, wavelength, angle of incidence, etc.) and may be designed to redirect light with different characteristics to a designated detection channel or the image sensor area of ​​the image sensor 105. The flat optics components 102 and 104 of the projector and image sensor can be positioned on the same substrate 103 (see Figure 8) or on different substrates (not shown). Other elements (a single element or an array of elements) can also be included and coupled with the image sensor, such as filters (e.g., spectral, polarization, spatial, and / or angular filters), refraction, diffraction, and / or reflective optical elements, optical modulators, liquid crystal elements, etc. One example is a pixelated spectral filter array or a single filter coupled with the image sensor. Another example is a pixelated polarization filter array or a single filter coupled with the image sensor.

[0046] Figure 9A schematically illustrates a multilayer flat optics architecture (e.g., a two-metasurface structure), which can be used to provide a customized image height-AOI relationship (e.g., minimized strain) with high imaging performance and a wide FOV. Preferably, two metasurfaces spaced apart longitudinally have the same size and their positions coincide when viewed longitudinally. First, this model can be used to design the single-metasurface case by assuming that the first metasurface layer has no phase and / or diffraction. For example, Figures 9B and 9C show two exemplary designs in which one of the two metasurfaces uses a four-phase profile and the other has zero phase. In both cases, the position of the focal point (or conversely, the position of the light-emitting element) increases linearly with sin(α), where α is the AOI (or projected beam angle).

[0047] In Figures 9A to 9C, n1 and n2 represent the refractive indices of the two substrate layers (between the two metasurfaces and between the image plane and the second metasurface, respectively), D and f represent the thicknesses of the two substrate layers, r1 and r2 represent the positions on the first and second metasurfaces, respectively, and s represents the position of the image plane. φ1 and φ1 are the phase profiles of the first and second metasurfaces, respectively.

[0048] A specific example of lens phase profile design in the case of a four-phase system is given below with reference to Figure 9D. The phase gradient at radius r is:

number

[0049] The ideal phase profile is,

number

[0050] Consider the following VCSEL at position r+δr:

number

[0051] Subtracting equation (2) from equation (3), using equation (1), and assuming that s is small,

number

[0052] This yields a four-phase profile:

number

[0053] A two-layer flat optics architecture can be used to customize the relationship between image height and AOI (e.g., minimizing distortion) while providing high imaging quality. Figure 10A shows an exemplary design using two phase profiles that produce a proportional relationship between image height and AOI (or conversely, between the position of the light-emitting element and the beam projection angle), i.e., s = f·α / n. Figure 10B shows the simulation results of the far-field angular distribution for such a projector design that produces a high-quality beam evenly distributed across the angular domain, assuming the light-emitting element array has equally spaced light-emitting elements. In comparison, with a single metasurface (e.g., using a four-phase profile), the resulting pattern becomes increasingly distorted as the AOI increases, as shown in Figure 10C.

[0054] Furthermore, one or both phase profiles can be superimposed with one or more beam splitting phase profiles to provide combined optical shaping, projection, and / or splitting functions. Additional optical elements may be used to further improve performance and incorporate new functions.

[0055] The multilayer flat optics design architecture described herein can simultaneously suppress aberrations and distortions, and can also provide additional beam manipulation capabilities.

[0056] In summary, the flat optics-based optical pattern generation architecture according to embodiments of the present invention employs hybrid meta-optics that combine beam projection, splitting, deflection, and / or shaping using one or more optical components for optimal performance. These enable high beam quality, such as near diffraction limiting and a wide field of view, for example, up to 180°; customizable projection patterns and / or channel densities in 2D or 3D; illumination patterns not limited to dots; and high efficiency compared to DOE elements.

[0057] Those skilled in the art will see that the flat optics-based optical pattern generation architecture and related methods of the present invention can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the present invention is intended to encompass modifications and changes that fall within the scope of the accompanying claims and their equivalents.

Claims

1. In a light pattern projection device, One or more light-emitting elements, A light pattern projection device comprising: a first optical metasurface coupled to one or more light-emitting elements and configured to project, reshape, and / or split a light beam generated by the one or more light-emitting elements to generate a projected light pattern, wherein the first metasurface layer comprises at least two superimposed phase profiles that perform different functions from each other, and each of the at least two phase profiles is configured to modulate, collimate, focus, diverge, deflect, shape, split, diffract, or diffuse the light beam from the one or more light-emitting elements.

2. The apparatus according to claim 1, further comprising a second optical metasurface spaced apart from the first optical metasurface, the second optical metasurface including an optical shaping and / or projection phase profile configured to collimate, focus, and / or deflect the light beams from the one or more light-emitting elements, and the first and second optical metasurfaces cooperating with each other to produce a predetermined relationship between the position or optical properties of the light-emitting elements and the corresponding beam projection angle or optical properties.

3. The apparatus according to claim 2, wherein the aforementioned predetermined relationship is a linear relationship between the position of the light-emitting element and the beam projection angle.

4. The apparatus according to claim 2, wherein the first and second optical metasurfaces have the same size.

5. The apparatus according to claim 1, wherein at least one of the two superimposed phase profiles splits or diffracts the light to spatially or angularly disperse the light beam from each of the one or more light-emitting elements into a plurality of channels.

6. The apparatus according to claim 5, comprising a plurality of light-emitting elements, wherein the projection light pattern comprises a plurality of subpatterns, each corresponding to one of the light-emitting elements.

7. The apparatus according to claim 6, wherein, in the projection light pattern, the plurality of subpatterns have the same shape and are offset from each other, and the plurality of subpatterns either overlap or do not overlap with each other.

8. The apparatus according to claim 1, wherein the projected light pattern is a 2D or 3D pattern comprising one or more of the following: dots, lines, matrices, characters, graphics, holograms, random patterns, grayscale patterns, uniform patterns, and diffuse patterns.

9. The apparatus according to claim 1, wherein the projected light pattern reaches a diagonal field of view of approximately 170°.

10. The apparatus according to claim 1, further comprising a spacer positioned between the first optical metasurface and the one or more light-emitting elements.

11. The apparatus according to claim 1, wherein the first optical metasurface is flat, curved, or conformally integrated with the substrate.

12. The apparatus according to claim 1, wherein the one or more light-emitting elements are one or more light sources, one or more optical channels, an image, or a light pattern.

13. The apparatus according to claim 1, comprising a plurality of light-emitting elements, wherein the first optical metasurface is configured to provide different responses to different characteristics of light from the plurality of light-emitting elements, the characteristics of the light being the wavelength, polarization, angle of incidence, or intensity of the light beam.

14. The apparatus according to claim 1, wherein the light-emitting element or a plurality of light-emitting elements are configured to emit light beams having the same or different optical properties, the optical properties being wavelength, polarization, beam divergence angle, or order.

15. In an optical pattern projection detection device including the optical pattern projection device described in claim 1, Other optical metasurfaces configured to modulate, shape, collimate, focus, diverge, deflect, split, diffract, or diffuse the aforementioned light beam, One or more photodetectors coupled to the other optical metasurface, A light pattern projection detection device further includes a light pattern detection device that includes a light pattern detection device.

16. The apparatus according to claim 15, wherein the first optical metasurface and the other optical metasurface are formed on separate, partially overlapping, or completely overlapping portions of the same substrate.

17. The apparatus according to claim 15, wherein the light receiver includes a photodetector or an optical channel.

18. In a light pattern projection device, A light-emitting array containing multiple light-emitting elements, A light pattern projection device comprising: one or more flat optics layers configured to project and divide a light beam generated by the plurality of light-emitting elements to generate a projected light pattern, wherein the projected light pattern comprises a plurality of subpatterns, each corresponding to one of the light-emitting elements, and the subpatterns are of the same shape, offset from each other, and overlap each other.

19. In a light pattern projection detection device including the light pattern projection device described in claim 18, A further flat optics layer configured to modulate, shape, collimate, focus, diverge, deflect, split, diffract, or diffuse the aforementioned light beam, A photodetector coupled to the aforementioned other flat optics layer, A light pattern projection detection device further includes a light pattern detection device that includes a light pattern detection device.

20. In a light pattern projection device, A light-emitting array containing multiple light-emitting elements, Optical pattern projection apparatus including superimposed phase profiles, comprising: a flat optics layer coupled to the light-emitting array and configured to project, reshape, and / or split light beams generated by the plurality of light-emitting elements to generate a projected light pattern, wherein the projected light pattern comprises a plurality of subpatterns, each corresponding to one of the light-emitting elements, and the flat optics layer includes a phase profile for beam collimation and projection configured to combine light beams from different light-emitting elements in different regions of the flat optics, and a beam splitting phase profile configured to spatially disperse the light beams from each light-emitting element into a plurality of channels.

21. In a light pattern projection detection device including the light pattern projection device described in claim 20, A further flat optics layer configured to modulate, shape, collimate, focus, diverge, deflect, split, diffract, or diffuse the aforementioned light beam, A photodetector connected to the aforementioned other flat optics layer, A light pattern projection detection device further includes a light pattern detection device that includes a light pattern detection device.

22. In a light pattern projection device, One or more light-emitting elements, A flat optics layer coupled to the light-emitting element or array of light-emitting elements, configured to project, reshape, and / or divide the light beam generated by the light-emitting element or a plurality of light-emitting elements to generate a projected light pattern, A light pattern projection device including a light pattern projection device.

23. The apparatus according to claim 22, comprising a plurality of light-emitting elements, wherein the projection light pattern comprises a plurality of subpatterns, each corresponding to one of the non-light-emitting elements.

24. The apparatus according to claim 22, wherein one flat optics layer is an optical metasurface including superimposed phase profiles, which include an optical shaping and / or projection phase profile configured to collimate, focus, and / or deflect the light beams from the light-emitting element or a plurality of light-emitting elements, and a beam splitting phase profile configured to spatially or angularly disperse the light beams from each light-emitting element into a plurality of channels.

25. In a light pattern projection device, One or more light-emitting elements, An optical pattern projection device comprising: two flat optics layers spaced apart from each other and having the same size, configured to project, reshape, and / or divide a light beam generated by the light-emitting element or a plurality of light-emitting elements to generate a projected light pattern, wherein the projected light pattern comprises a plurality of subpatterns, each corresponding to one of the light-emitting elements.

26. The apparatus according to claim 25, wherein each of the two flat optics layers includes an optical shaping, projection, and / or splitting phase profile configured to collimate, focus, deflect, and / or split the light beam from the light-emitting element or a plurality of light-emitting elements, the two flat optics layers cooperate with each other to realize a predetermined relationship between the position or optical characteristics of the light-emitting element and the corresponding beam projection angle, and at least one of the two flat optics layers further includes a superimposed beam splitting phase profile configured to spatially disperse the light beam from each light-emitting element into a plurality of channels.

27. The apparatus according to claim 26, wherein the aforementioned predetermined relationship is a linear relationship between the position of the light-emitting element and the beam projection angle.

28. In a light pattern projection device, One or more light-emitting elements, Configured to project, reshape, and / or split a light beam generated by the light-emitting element or a plurality of light-emitting elements, which are spaced apart from each other, to generate a projected light pattern, wherein the projected light pattern comprises two optical metasurfaces, each containing a plurality of subpatterns corresponding to one of the light-emitting elements, Includes, An optical pattern projection device comprising superimposed beam splitting phase profiles, wherein each of the two optical metasurfaces includes an optical shaping, projection, and / or splitting phase profile configured to collimate, focus, and / or deflect the light beam from the light-emitting element or a plurality of light-emitting elements, the two optical metasurface sizes cooperate with each other to generate a predetermined relationship between the position or optical properties of the light-emitting element and the beam projection angle, and at least one of the two optical metasurfaces includes an optical pattern projection device comprising superimposed beam splitting phase profiles configured to spatially disperse the light beam from each light-emitting element into a plurality of channels.

29. The apparatus according to claim 28, wherein the aforementioned predetermined relationship is a linear relationship between the position of the light-emitting element and the beam projection angle.

30. The apparatus according to any one of claims 18, 20, 22, 25, and 28, wherein the projected light pattern is a 2D or 3D pattern comprising one or more arrays of dots, lines, matrices, characters, graphics, holograms, random patterns, grayscale patterns, uniform patterns, and diffuse patterns.

31. The apparatus according to any one of claims 18, 20, 22, 25, and 28, wherein the projected light pattern reaches a diagonal field of view of approximately 170°.

32. The apparatus according to any one of claims 18, 20, 22, 25, and 28, further comprising a spacer positioned between the flat optics layer and the one or more light-emitting elements.

33. The apparatus according to any one of claims 18, 20, 22, 25, and 28, wherein the flat optics layer is flat, curved, or conformally integrated with the substrate.

34. The apparatus according to any one of claims 18, 20, 22, 25, and 28, wherein the one or more light-emitting elements are one or more light sources, one or more optical channels, an image, or an optical pattern.

35. The apparatus according to any one of claims 18, 20, 22, 25, and 28, comprising a plurality of light-emitting elements, wherein the flat optics layer is configured to provide different responses to different characteristics of light from the plurality of light-emitting elements, the characteristics of the light being the wavelength, polarization, angle of incidence, or intensity of the light beam.

36. The apparatus according to any one of claims 18, 20, 22, 25, and 28, wherein the light-emitting element or a plurality of light-emitting elements are configured to emit light beams having the same or different optical properties, the optical properties being wavelength, polarization, beam divergence angle, or order.

37. A light pattern projection detection device including a light pattern projection device according to any one of claims 22, 25, and 28, A further flat optics layer configured to modulate, shape, collimate, focus, diverge, deflect, split, diffract, or diffuse the aforementioned light beam, A photodetector coupled to the flat optics layer, A light pattern projection detection device further includes a light pattern detection device that includes a light pattern detection device.

38. The apparatus according to claim 37, wherein the flat optics layer and the other flat optics layer are formed on another, partially overlapping, or completely overlapping portion of the same substrate.

39. The apparatus according to claim 37, wherein the light receiver includes a photodetector or an optical channel.

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