Optical element including a metasurface, light beam pattern projector, method of manufacturing an optical element, computer-implemented method

Abstract

An optical element including a substrate with multiple nanostructures (metasurfaces) on the substrate and a superstrate, wherein each metasurface has a defined position on the substrate and a designed combination of variable heights meta-atoms such that a light beam profile of incoming light having a predetermined wavelength is converted to an output light beam pattern.

Description

[0001] Sony Semiconductor Solutions Corporation et al.

[0002] OPTICAL ELEMENT INCLUDING A METASURFACE, LIGHT BEAM PATTERN PROJECTOR, METHOD OF MANUFACTURING AN OPTICAL ELEMENT, COMPUTER-IMPLEMENTED METHOD TECHNICAL FIELD

[0003] The present disclosure generally pertains to an optical element including a metasurface converting a light beam profile of incoming light to an output light beam pattern with desired field-of-view, a method of manufacturing such an optical element, a light beam pattern projector, and a computer-implemented method.

[0004] TECHNICAL BACKGROUND

[0005] The generation of light beam patterns, such as a line or dot array beam pattern, that have a wide field of view (“FOV”), is known, for example, for (mobile) depth and surface perception related applications in consumer electronics and machine vision systems like face identification and Light Detection and Ranging (“LiDAR”) methods. The FOV may sometimes also be referred to as field of illumination (“FO ’).

[0006] To generate a light beam pattern, an optical element may be used that converts a light beam profile of incoming light incident on the optical element to an output light beam pattern. The incoming light may, for instance, be generated by an active light source.

[0007] Some known optical elements that refract and / or diffract light beam profiles of incoming light may be based on glass or plastic materials that have a low refractive index and are suitable for mass production. Such optical elements for structured light generation are typically based on diffractive optical elements (“DOEs”). These DOEs are based, for example, on binary-phase gratings.

[0008] However, such optical elements are typically limited to a FOV of the output light beam pattern of less than 60 degrees, as optical elements designed for an even wider FOV - i.e., a FOV greater than 60 degrees - may exhibit in some cases a low transmission efficiency and / or a low uniformity of the intensities of the diffraction orders of the output light beam pattern.

[0009] More recently, optical elements with a metasurface made of high refractive index material achieved better results compared to conventional methods, wherein the better results comprise higher transmission efficiencies and higher uniformities.Sony Semiconductor Solutions Corporation et al.

[0010] However, the fabrication of optical elements from materials having a high refractive index is rather complex for mass production compared to optical elements made of low refractive index materials and often requires electron-beam lithography-based processes.

[0011] Although there exist techniques for optical elements that convert a light beam profile of incoming light to an output light beam pattern, it is generally desirable to improve the existing techniques.

[0012] SUMMARY

[0013] According to a first aspect, the disclosure provides an optical element, comprising:

[0014] a substrate body; and

[0015] a measurface consisting of nanostructures building patterns attached on top of the substrate body, wherein each nanostructure has a position on the substrate body and one or more geometric parameters including a height such that a light beam profile of incoming light having a predetermined wavelength is converted to an output light beam pattern.

[0016] According to a second aspect, the disclosure provides a light beam pattern projector, comprising:

[0017] an optical element including:

[0018] a substrate body, and

[0019] a metasurface consisting of nanostructures building patterns attached on top of the substrate body, wherein each nanostructure has a position on the substrate body and one or more geometric parameters including a height such that a light beam profile of incoming light having a predetermined wavelength is converted to an output light beam pattern; and

[0020] a light source configured to emit the light beam profile incident on the optical element such that the optical element coverts the light beam profile to the output light beam pattern. According to a third aspect, the disclosure provides a method of manufacturing an optical element comprising:

[0021] forming the optical element by injection molding, wherein the optical element includes:

[0022] a substrate body, and

[0023] a metasurface consisting of nanostructures building patterns attached on top of the substrate body, wherein each nanostructure has a position on the substrate body and one or more geometric parameters including a height such that a light beam profile of incoming light having a predetermined wavelength is converted to an output light beam pattern.Sony Semiconductor Solutions Corporation et al.

[0024] According to a fourth aspect, the disclosure provides a computer-implemented method, comprising:

[0025] obtaining data representing a light beam profile of incoming light, a predetermined wavelength of the light beam profile of incoming light and a target output light beam pattern with a target field-of-view;

[0026] obtaining data representing geometric parameter ranges for nanostructures; simulating a light propagation through an optical element having a substrate body and a metasuface consisting of nanostructures building patterns attached on top of the substrate body to obtain a simulated output light beam pattern, wherein the simulation is based on the light beam profile of incoming light and the predetermined wavelength as input; and

[0027] optimizing the position and the geometric parameters of each nanostructure, the geometric parameters including a height, by minimizing a root mean square error, RMSE, given by

[0028] N2

[0029] RMSE= N- V ,

[0030] 4^ Min N /

[0031]

[0032] wherein N is the number of diffraction orders of the target output light beam pattern in accordance with the target field-of-view and L is the intensity of the i-th diffraction order of the simulated output light beam pattern normalized by the average intensity Im of the incoming light incident on the optical element.

[0033] Further aspects are set forth in the dependent claims, the drawings, and the following description.

[0034] BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Embodiments are explained by way of example with respect to the accompanying drawings, in which:

[0036] Fig. 1 schematically illustrates in a block diagram an embodiment of a light beam pattern projector;

[0037] Fig. 2A schematically illustrates in a block diagram an embodiment of an optical element;

[0038] Fig. 2B schematically illustrates in a block diagram an embodiment of a section of a periodic pattern of nanostructures;

[0039] Fig. 2C schematically illustrates in a block diagram an embodiment of a nanostructure;Sony Semiconductor Solutions Corporation et al.

[0040] Fig. 3 schematically illustrates an embodiment of intensities of a plurality of diffraction orders of a two-dimensional output light beam pattern;

[0041] Fig. 4 schematically illustrates in a flow diagram an embodiment of a method of manufacturing an optical element;

[0042] Fig. 5 schematically illustrates in a flow diagram an embodiment of a computer-implemented method;

[0043] Fig. 6 schematically illustrates in a flow diagram an embodiment of a computer-implemented method; and

[0044] Fig. 7 schematically illustrates in a block diagram an embodiment of a multi-purpose computer which can be used for implementing an information processing device.

[0045] DETAILED DESCRIPTION OF EMBODIMENTS

[0046] Before a detailed description of the embodiments under reference of Fig. 1 is given, general explanations are made.

[0047] As mentioned in the outset, a wide range of applications relies on devices generating structured light for depth and surface perception, comprising, for example, face identification in consumer electronics and LiDAR techniques.

[0048] Optical elements used in the process of generating structured light may comprise a patterned surface and convert a light beam profile of incoming light to an output light beam pattern.

[0049] In conventional approaches, the output light beam pattern may have a limited FOV, thus covering only a small extent of the scene at hand and, in some cases, may have a low transmission efficiency and / or low uniformity.

[0050] In recent developments, as also mentioned in the outset, materials with high refractive indices are used to form optical elements with a metasurface with higher transmission efficiencies and uniformities. However, such optical elements may require more complex manufacturing methods such as electron-beam lithography.

[0051] Electron-beam lithography is a maskless lithography technique wherein a beam of accelerated electrons patterns custom features on a substrate covered with an electron-sensitive resist, followed by exposure and development of the resist. While allowing for customized, high-resolution patterning, electron-beam lithography may be, in some cases, a low-throughput technique entailing high manufacturing costs when high-volume production is required.Sony Semiconductor Solutions Corporation et al.

[0052] It has been recognized that optical elements with a nanostructured surface having nanostructures of variable heights and diameters may be used to achieve a FOV exceeding 60 degrees along with a high transmission efficiency and uniformity.

[0053] Moreover, it has further been recognized that optical elements may be manufactured from low refractive index materials suitable for high-volume production such as a plastic, which allows to use nanofabrication techniques, for example, like injection molding, nano-imprint lithography, 3D (“three-dimensional”) nano-printing or two photon greyscale lithography.

[0054] In addition, it has further been recognized that optimizing the positions and geometric parameters of the nanostructures on a substrate body of the optical element may be derived by a computer-implemented method.

[0055] Hence, some embodiments pertain to an optical element, wherein the optical element includes:

[0056] a substrate body; and

[0057] a metasurface consisting of nanostructures building patterns attached on top of substrate body, wherein each nanostructure has a position on the substrate body and one or more geometric parameters including a height such that a light beam profile of incoming light having a predetermined wavelength is converted to an output light beam pattern.

[0058] The optical element may be used in applications relying on depth and surface perception. Such applications may include face identification in consumer electronics and LiDAR techniques used in various fields, for example, geology or autonomous driving, without limiting embodiments to these applications.

[0059] The substrate body may be a three-dimensional body that is plate-shaped or that has a cylindrical shape or that is shaped as a truncated cone, without limiting the disclosure in this regard, and may have a surface from which nanostructures protrude. For example, the substrate body may also be shaped as a sphere.

[0060] The substrate body may have a first surface side through which incoming light enters the optical element and a second surface side opposite to the first surface side through which the transmitted part of the incoming light leaves the optical element such that the output light beam pattern is generated. The nanostructures of the metasurface may protrude from the first or the second surface side or partially from the first surface side and partially from the second surface side. Generally, metasurfaces are two-dimensional metamaterials with a thickness comparable to or below the wavelength of interest. Typically, metamaterials are engineered structures designed to interact with electromagnetic waves in a desired fashion, wherein properties of metamaterialsSony Semiconductor Solutions Corporation et al.

[0061] may not be found in naturally occurring materials and may stem from their internal structure and the arrangement of meta-atoms building them rather than their chemical composition.

[0062] Generally, meta-atoms, which may also be referred to as nanostructures, may be building blocks of metamaterials and metasurfaces and may have a size smaller than the wavelengths of interest in a lateral direction. For example, meta-atoms may be smaller or comparable (e.g., up to two times) to the wavelengths of interest in direction of light incidence. Typically, meta-atoms may have a precise shape, geometry, size, orientation, composition, and arrangement, giving the metamaterial or metasurface its novel and smart properties.

[0063] In general, non-identical meta-atoms can be used to build up one metamaterial or metasurface. Generally, metasurfaces may be any arrangement in between: spatially highly inhomogeneous, with generally non-identical meta-atoms placed on a generally aperiodic lattice; and (essentially) periodic with identical meta-atoms placed in a periodic lattice (including photonic crystal slab geometries).

[0064] Generally, metasurfaces may dominantly inherit properties from their individual meta-atoms and their resonant properties.

[0065] Nanostructures may be three-dimensional structures having, at least along one spatial dimension, an extent on the nanoscale. In other words, the extent of a nanostructure along at least one spatial dimension is sized in the nanometer range. For example, at least one spatial dimension may be less than 1000 nanometers, without limiting the disclosure in this regard.

[0066] The nanostructures may have a cylindrical shape, a conical shape, a cuboidal shape, a spherical shape, a pyramidical shape, a prism-shape or the like. The cylindrical shape may have a circular base area or an elliptical base area for example.

[0067] A nanostructure has one or more geometric parameters that may describe the spatial extent of a nanostructure along at least one spatial dimension. The geometric parameters include a height which may be a spatial distance between a portion of a nanostructure closest to a surface of the substrate body from which nanostructures protrude and a portion of a nanostructure farthest away from the surface of the substrate body from which nanostructures protrude. Another geometric parameter may be a diameter, for example, when the nanostructures have a cylindrical shape with a circular base area.

[0068] The incoming light, having a light beam profile, may be incident on a surface of the substrate body, as mentioned above. The light beam profile of incoming light may have a spatial GaussianSony Semiconductor Solutions Corporation et al.

[0069] light beam profile or any other light beam profile. The light beam profile may have a narrow wavelength range (e.g., in terms of the full width at half maximum ("FWHM”) in the spectral domain) in the ultraviolet or visible or near infrared region of the electromagnetic spectrum. The conversion of the light beam profile of incoming light may be impacted by the positions and geometric parameters of the nanostructures on the substrate body and may include a conversion of the amplitude and / or phase and / or polarization of the light beam profile of incoming light. In some embodiments, the output light beam pattern may have a plurality of diffraction orders, wherein a root mean square error, RMSE, given by

[0070]

[0071] is less than or equal to 10% (percent), wherein N is the number of diffraction orders and li is the intensity of the i-th diffraction order normalized by the average intensity Im of the incoming light incident on the optical element.

[0072] The light beam profile of incoming light is refracted and diffracted in particular by the nanostructures such that the output light beam pattern has one or more diffraction orders along one or more spatial dimensions. In other words, the optical element refracts and diffracts the light beam profile of incoming light into one or more diffraction orders of the output light beam pattern.

[0073] The optical element may be provided such that, in an ideal case, in some embodiments, the average intensity of the incoming light incident on the optical element is equally distributed among the plurality of diffraction orders. That is, in an ideal case, in some embodiments, the intensity of each diffraction order equals the reciprocal of the number of diffraction orders of the output light beam pattern. The intensity in the ideal case is referred to as theoretical intensity hereafter.

[0074] For each diffraction order of the output light beam pattern, the deviation between a measured intensity and the theoretical intensity is squared. After adding up the squared deviations of the plurality of diffraction orders, the root mean squared error is calculated as the root of the mean squared deviations and therewith quantifies the average deviation of measured intensities of the plurality of diffraction orders of the output light beam pattern from the theoretical intensities.Sony Semiconductor Solutions Corporation et al.

[0075] The uniformity of the intensities of the plurality of diffraction orders of the output light beam pattern relates to the highest intensity Imax and to the lowest intensity Imin of the intensities of the pluralities of diffraction orders and is given by

[0076] lmax“lniiii

[0077]

[0078] l|iiax+l|iiin

[0079] In case the average intensity of the incoming light is equally distributed among the intensities of the plurality of diffraction orders, Imax = Imin, resulting in a uniformity of 0%, whereas in case Imax equals the average intensity of the incoming light, Imin = 0, resulting in a uniformity of 100%. Therewith, the uniformity may take on values between 0% and 100%. In other words, the uniformity as defined above indicates how much the maximum intensity and the minimum intensity deviate such that a low value indicates a high degree of uniformity of the intensity distribution in the plurality of diffraction orders and vice versa. In some embodiments, the uniformity as defined above is thus referred to as a uniformity deviation.

[0080] In some embodiments, the uniformity is less than or equal to 1% (percent).

[0081] In some embodiments, the measured transmission efficiency of an optical element, given by

[0082]

[0083] lin ’

[0084] is greater than or equal to 90% (percent), wherein N is the number of diffraction orders of the output light beam pattern, L is the intensity of the i-th diffraction order and lin is the average intensity of the incoming light incident on the optical element.

[0085] In case the sum of the intensities of the diffraction orders equals the average intensity of the incoming light, the transmission efficiency is 100%, whereas in case the sum of the intensities of the diffraction orders equals zero, the transmission efficiency is 0%.

[0086] In some embodiments, the optical element includes a material that has a refractive index greater than or equal to 1.3 and less than or equal to 1.9, which may be an optical plastic that includes at least one of polymethyl methacrylate, polystyrene, or polycarbonate, or any other chemical compound.

[0087] The refractive index of the material included in the optical element depends on the wavelength of the light incident on the optical element. The light beam profile of incoming light has a predetermined wavelength. In some embodiments, the wavelength may be greater than or equal to 300 nanometers and less than or equal to 2000 nanometers, without limiting the disclosure in this regard.Sony Semiconductor Solutions Corporation et al.

[0088] In some embodiments, the output light beam pattern may have a FOV greater than 60 degrees. The FOV may be quantified by an angle describing the spatial extent of the output light beam pattern in a horizontal and / or vertical dimension. For instance, the spatial extent of the output light beam pattern may be marked by two points at two outermost portions of the output light beam pattern in one spatial dimension, wherein the outermost portion may correspond, for example, to the highest diffraction orders. Connecting each of the two points to a point on the optical element creates two straight lines spanning the angle that quantifies the FOV with respect to a spatial dimension. The spatial dimension may be a horizontal, vertical, or any other dimension.

[0089] In some embodiments, the output light beam pattern may include a line pattern, a dot pattern, or any other pattern. In case of a dot pattern, the intensity of the incoming light incident on the optical element may be diffracted into a plurality of diffraction orders of the output light beam pattern, wherein each dot of the dot pattern may correspond to one diffraction order of the plurality of diffraction orders.

[0090] In some embodiments, nanostructures provided on the substrate body may be positioned according to sections of a periodic pattern, wherein each section may include a plurality of nanostructures such that, in each section, each nanostructure of the plurality of nanostructures may have the same relative position and the same geometric parameters.

[0091] A surface of the substrate body from which nanostructures protrude may conceptually be subdivided into sections. The sections may be sized equally or have different sizes. The sections may be arranged according to a periodic or recurring pattern, i.e., the sections may be arranged next to each other along the spatial dimensions of the surface of the substrate body from which nanostructures protrude and may thus be repeated. Such sections may also be referred to as unit cells or super cells.

[0092] A section may include a plurality of nanostructures. Each section may include the same or different pluralities of nanostructures. A section may include any number of nanostructures. Within a section, a nanostructure may be provided at a relative position. The relative position may be relative to the section and / or relative to the other nanostructures within the section.

[0093] Considering more than one section, more than one nanostructure may have the same relative position. Nanostructures having the same relative position may have the same particular set of geometric parameters or may differ in the set of geometric parameters.Sony Semiconductor Solutions Corporation et al.

[0094] Nanostructures within a section or, more generally, nanostructures provided on the substrate body, may have one or more geometric parameters that may be equal or different. For example, two cylindrical nanostructures within a section may have the same height and different diameters, different heights and the same diameter, the same height and the same diameter, or different heights and different diameters.

[0095] The sections including the pluralities of nanostructures may function as a grating that diffracts the light beam profile of incoming light incident on the optical element into a plurality of diffraction orders of the output light beam pattern.

[0096] In some embodiments, the nanostructures protruding from the substrate body are provided in a predetermined symmetry.

[0097] In some embodiments, the predetermined symmetry is an axial symmetry in case of a onedimensional output light beam pattern, and a fourfold rotational symmetry in case of a two-dimensional output light beam pattern.

[0098] In an axial symmetry, an object is axially symmetric. In some embodiments, given the entirety of nanostructures provided on the substrate body represents an object, the entirety of nanostructures may be mapped onto itself by mirroring with respect to an axis, i.e., the entirety of nanostructures is axially symmetric. In some embodiments, the plurality of nanostructures within a section is provided in an axial symmetry.

[0099] Nanostructures provided in an axial symmetry on the substrate body of the optical element may render a one-dimensional output light beam pattern independent of the polarization of the light beam profile of incoming light incident on the optical element.

[0100] Likewise, in a fourfold rotational symmetry, an object appears identical when rotated at certain angels with respect to four axes. In some embodiments, given the entirety of nanostructures provided on the substrate body represents an object, the entirety of nanostructures may be mapped onto itself by rotation at a certain angle, i.e., the entirety of nanostructures is partially rotationally symmetric. The angle of rotation may be 90 degrees. In some embodiments, the plurality of nanostructures within a section is provided in a fourfold rotational symmetry.

[0101] Nanostructures provided in a fourfold rotational symmetry on the substrate body of the optical element may render a two-dimensional output light beam pattern independent of the polarization of the light beam profile of incoming light incident on the optical element.Sony Semiconductor Solutions Corporation et al.

[0102] In some embodiments, each nanostructure provided on the substrate body has substantially the same shape. The shape of a nanostructure may be a geometric object. The shape of a nanostructure may be a sphere, a cylinder, a cone, or any other shape, as mentioned above. In some embodiments, each nanostructure has substantially the same shape, the shape of a nanostructure may be substantially a cylindrical shape.

[0103] In some embodiments, each nanostructure has substantially a cylindrical shape, each nanostructure may have a diameter greater than or equal to 100 nanometers and less than or equal to 1000 nanometers.

[0104] In some embodiments, each nanostructure has substantially a cylindrical shape, the distance between any two nanostructures may be greater than 100 nanometers.

[0105] In some embodiments, each nanostructure has substantially a cylindrical shape, each nanostructure may have a height of less than 2.5 micrometers.

[0106] In some embodiments, each nanostructure has substantially a cylindrical shape, each nanostructure may have an aspect ratio of less than 5:1, wherein the aspect ratio corresponds to the ratio of the height to the diameter.

[0107] In some embodiments, the nanostructures provided on the substrate body have geometric parameters and positions, wherein the geometric parameters and positions are determined according to the computer-implemented method described herein.

[0108] Some embodiments pertain to a light beam pattern projector, wherein the light beam pattern projector includes:

[0109] an optical element including:

[0110] a substrate body, and

[0111] a metasurface consisting of nanostructures building patterns attached on top of the substrate body, wherein each nanostructure has a position on the substrate body and one or more geometric parameters including a height such that a light beam profile of incoming light having a predetermined wavelength is converted to an output light beam pattern; and

[0112] a light source configured to emit the light beam profile incident on the optical element such that the optical element coverts the light beam profile to the output light beam pattern. The (active) light source of the incoming light may be a vertical cavity surface emitting laser (“VCSEL”), an edge emitting semiconductor laser or any other light source, for example, a light emitting diode (“LED”). A collimator, i.e., a device substantially parallelizing rays of theSony Semiconductor Solutions Corporation et al.

[0113] incoming light beam, and / or a lens or the like may be provided between the light source of the incoming light and the optical element. Moreover, an aperture may be provided between the light source of the incoming light and the optical element.

[0114] Some embodiments pertain to a method of manufacturing an optical element, as discussed herein, including forming the optical element by injection molding, wherein molten material is injected into a mold where the material cools and hardens. The optical element may be formed in one piece. The manufacturing method is also discussed under reference of Fig. 4 further below. In some embodiments, the optical element may be formed by nanofabrication techniques such as nanoimprint lithography, three-dimensional nano-printing, two photon greyscale lithography, or any other manufacturing method, as mentioned above. The manufacturing method may be of low cost and / or suitable for mass production.

[0115] Summarizing some aspects of some embodiments:

[0116] The light beam pattern generation may be based on an optical element made of a low refractive index material having an index between 1.0 and 1.9 (e.g., plastic), which is suitable for low-cost mass production by nanofabrication techniques like injection molding, nano-imprint lithography, 3D (three-dimensional) nano-printing, or two photon greyscale lithography.

[0117] The optical element may be designed for specific narrow-band wavelengths in the near-infrared spectral region (e.g., 940 nanometers) and may be for on-chip integration on VCSEL or other light sources, or act as standalone optical element.

[0118] The optical element may consist of a metasurface, which is a surface consisting of similar or different nanosized structures (called meta-atoms) arranged to interact with incoming light in a specific way. Here, the interaction may be in such a way that the outgoing light forms a specific, wide FOV, ID (one-dimensional) or 2D (two-dimensional) beam pattern in the far field like dot array, line array, or any other coded pattern. The meta-atoms may be varied in height and / or diameter to individually and / or collectively change the local phase and / or local amplitude of the incoming light.

[0119] The metasurface may consist of repeating unit cells, the size of which is specific for the wavelength of incoming light and desired wide FOV between 60 degrees-120 degrees or even larger than 120 degrees, to allow the efficient and uniform diffraction of the incoming light up to a specific diffraction order for ID (line pattern) or 2D (dot pattern) and suppress higher diffraction orders. The size may be calculated by the known grating equation.Sony Semiconductor Solutions Corporation et al.

[0120] The unit cell itself may be a supercell consisting of an arrangement of meta-atoms varying in diameter and / or height. The number of meta-atoms may be 5 to 10 (ID) or between 5x5 to 10x10 (2D). The meta-atoms are arranged in a mirror (ID) or fourfold rotational symmetry (2D) to ensure independence of the polarization of the incoming light. Each meta-atoms’ diameter, height, and / or relative position within the supercell is optimized to ensure the uniform (< ±20%) transmission of the incoming light into each diffraction order with a high overall transmission efficiency (> 60%). The meta-atoms may be in cylindrical form with diameters between 100-1000 nanometers, aspect ratios < 5:1, and distances of > 100 nanometers between the meta-atoms as well as a total of up to eight arbitrarily different height levels of all meta-atoms with the maximum height being < 2.5 micrometers.

[0121] Metasurfaces based on this concept for (mobile) applications in consumer electronics, machine vision systems, or others, like face identification, LiDAR, or other depth and surface perception related applications.

[0122] In particular:

[0123] A metasurface design for dot pattern generation of 9x9 dots (in circular shape total of 69 diffraction orders) with FOV of 120 degrees at 940 nanometers wavelength for plastic material with refractive index of n = 1.67 may be obtained. A representation of the designed supercell with size 4.34 micrometers x 4.34 micrometers, for example, is shown in Fig. 2B. The supercell has a fourfold rotational symmetry and consists of ten different meta-atoms with eight different height levels between 280-2345 nanometers, diameters between 250-520 nanometers, aspect ratio < 5:1, and distance > 100 nanometers between the meta-atoms. In simulation, this metasurface has a high transmission efficiency of 90%. The uniformity of the transmitted intensity into all 69 diffraction orders is very high and < ±1% of the average intensity (see Fig.

[0124] 3).

[0125] Some embodiments pertain to a computer-implemented method, including:

[0126] obtaining data representing a light beam profile of incoming light, a predetermined wavelength of the light beam profile of incoming light and a target output light beam pattern with a target field-of-view;

[0127] obtaining data representing geometric parameter ranges for nanostructures; simulating a light propagation through an optical element having a substrate body and a metasurface consisting of nanostructures building patterns attached on top of the substrate body to obtain a simulated output light beam pattern, wherein the simulation is based on the light beam profile of incoming light and the predetermined wavelength as input; andSony Semiconductor Solutions Corporation et al.

[0128] optimizing the position and the geometric parameters of each nanostructure, the geometric parameters including a height, by minimizing a root mean square error, RMSE, given by

[0129]

[0130] wherein N is the number of diffraction orders of the target output light beam pattern in accordance with the target field-of-view and L is the intensity of the i-th diffraction order of the simulated output light beam pattern normalized by the average intensity Im of the incoming light incident on the optical element.

[0131] The computer-implemented method may be performed or executed by an information processing device. The information processing device may be a mobile computing device (e.g., a smartphone, a tablet, a laptop), a computer, a server or the like.

[0132] The information processing device includes circuitry configured to perform the computer-implemented method.

[0133] The circuitry may include one or more processors. A processor may be or may include an application processor, a central processing unit (“CPU”), a graphical processing unit (“GPU”), a digital signal processor (“DSP”), a field-programmable gate array (“FPGA”), an application specific integrated circuit (“ASIC”) etc.

[0134] The circuitry may include one or more memory components. A memory component may be or may include volatile and non-volatile memory such as static random-access memory (“SRAM”), dynamic RAM (“DRAM”), non-volatile RAM (“NVRAM”), read-only memory (“ROM”), programmable ROM (“PROM”), electrically PROM (“EPROM”), electrically erasable PROM (“EEPROM”), flash memory (e.g., NOR flash or NAND flash) etc. A memory component may be or may include one or more registers, caches, main memories, hard disk drives, solid-state drives etc.

[0135] The circuitry may include one or more input / output interfaces, wherein to each input / output interface at least one or more peripheral devices and one or more communication interfaces may be connected to exchange data with at least one of the one or more processors and the one or more memory components. The data exchange may be in simplex, half-duplex or full-duplex mode. The data exchange may be serial or parallel. The data exchange may be synchronous or asynchronous.Sony Semiconductor Solutions Corporation et al.

[0136] The circuitry may be implemented by typical electronic components configured to achieve the functionality as described herein. The circuitry may be implemented in parts by typical electronic components and in parts by software configured to achieve the functionality as described herein. The circuitry may be implemented by software configured to achieve the functionality as described herein.

[0137] An optical element that has a substrate body and nanostructures protruding from the substrate body may convert a light beam profile of incoming light to an output light beam pattern, as discussed herein.

[0138] It is estimated that the nanostructures may be positioned, shaped and sized in various ways to provide a particular output light beam pattern, however, a concrete mathematical relationship between the desired output light beam pattern and the positions, shapes and geometric parameters of the nanostructures is difficult to obtain due to the complexity of the interaction between the light and the nanostructures.

[0139] It has thus been recognized that the positions and geometric parameters of the nanostructures should be determined based on a simulation and an optimization procedure.

[0140] Hence, the computer-implemented method is used to determine the geometric parameters of the nanostructures and the positions of the nanostructures on the substrate body.

[0141] The computer-implemented method includes obtaining data representing the light beam profile of incoming light that may comprise a phase, amplitude, and / or polarization of the incoming light beam.

[0142] In addition, the computer-implemented method includes obtaining data representing a predetermined wavelength of the light beam profile of incoming light which may be determined with regard to the refractive index of the material of the optical element, wherein the refractive index depends on the wavelength of the light beam profile of incoming light.

[0143] Moreover, the computer-implemented method includes obtaining data representing geometric parameter ranges for nanostructures that may be set to confine the results of the computer-implemented method to physically feasible orders of magnitude.

[0144] Furthermore, the computer-implemented method includes obtaining data representing a target output light beam pattern that serves as a reference in the optimization process. The target output light beam pattern may have one or more diffraction orders, wherein each of the diffractionSony Semiconductor Solutions Corporation et al.

[0145] orders has an intensity. In addition, the target output light beam pattern may comprise a two-dimensional dot array or any other pattern.

[0146] To determine the position and geometric parameters of each nanostructure, the computer-implemented method may include performing numerical simulations based on a set of discretized equations that model physical processes underlying the conversion of a light beam profile of incoming light to a simulated output light beam pattern by an optical element.

[0147] Computer-implemented methods for a physical simulation of light propagation through various materials of various structures are generally known and, thus, are not discussed in detail.

[0148] As the target output light beam pattern, the simulated output light beam pattern may have one or more diffraction orders, wherein each of the diffraction orders has an intensity. The computer-implemented method includes optimizing the positions and geometric parameters of the nanostructures such that the root mean squared difference of the intensities of the diffraction orders of the target output light beam pattern and the intensities of the diffraction orders of the simulated output light beam pattern is minimized.

[0149] The computer-implemented method as described herein may also be implemented in some embodiments as a computer program causing a computer and / or a processor to perform the method, when being carried out on the computer and / or processor. In some embodiments, also a non-transitory computer-readable recording medium is provided that stores therein a computer program product, which, when executed by a processor, such as the processor described above, causes the methods described herein to be performed.

[0150] Returning to Fig. 1, there is schematically illustrated in a block diagram an embodiment of a light beam pattern generator 1, which is discussed in the following.

[0151] The light beam pattern generator 1 includes an optical element 2 and a light source 3. The optical element 2 converts a light beam profile of incoming light 4. The incoming light 4, emitted by light source 3, is incident on the optical element 2. In the present embodiment, the incoming light 4 includes a wavelength of 940 nanometers and has a narrow spectral width, for example, of a few nanometers (e.g., ± 5 nanometers).

[0152] The optical element 2 converts the light beam profile of incoming light 4 to an output light beam pattern 5. The output light beam pattern 5 has a FOV 6. In the present embodiment, the FOV 6 is 120 degrees in a vertical and a horizontal spatial dimension, respectively.Sony Semiconductor Solutions Corporation et al.

[0153] Each dot 7 of the output light beam pattern 5 corresponds to a diffraction order of the output light beam pattern 5. In the present embodiment, the output light beam pattern 5 is a two-dimensional dot array comprising 69 dots 7 corresponding to 69 diffraction orders of the output light beam pattern 5.

[0154] Fig. 2A schematically illustrates in a block diagram an embodiment of the optical element 2 of Fig. 1.

[0155] The optical element 2 includes a substrate body from which nanostructures (not shown) protrude, wherein the nanostructures are positioned according to sections 2a of a periodic pattern, wherein each section includes a plurality of nanostructures such that, in each section, each nanostructure of the plurality of nanostructures has the same relative position and the same geometric parameters.

[0156] Fig. 2B schematically illustrates in a block diagram an embodiment of the section 2a of the periodic pattern of nanostructures of Fig. 2A, which is discussed in the following under reference of Figs. 2B and 2C.

[0157] The plurality of nanostructures 9 protruding from a surface of the substrate body 8 have a cylindrical shape with a height 11 and a diameter 12, as schematically illustrated in Fig. 2C. The section 2a including the plurality of nanostructures 9 has a size equal to 4340 nanometers by 4340 nanometers in the horizontal directions along the surface of the substrate body 8.

[0158] In the present embodiment, 49 nanostructures 9 are provided on the substrate body 8 and include ten different nanostructure types 9a-j, wherein each nanostructure 9 has a cylindrical shape. Each nanostructure type 9a-j has one of eight different heights 11 between 280 and 2345 nanometers, a diameter 12 between 250 and 520 nanometers, and an aspect ratio, relating the height 11 of a nanostructure to the diameter 12 of a nanostructure, of less than 5:1. The distance between any two nanostructures 9 is greater than 100 nanometers.

[0159] The plurality of nanostructures 9 is arranged in a fourfold rotational symmetry with respect to the center of the section 2a, such that the output light beam pattern 5 is independent of the polarization of the light beam profile of incoming light 4.

[0160] Nanostructure type 9a is provided at a central position on the substrate body 8, while the remaining nanostructure types 9b-h are arranged in substantially concentric circles around nanostructure type 9a with increasing radii from nanostructure types 9b to 9h.Sony Semiconductor Solutions Corporation et al.

[0161] In the present embodiment, the optical element 2 including the substrate body 8 and the plurality of nanostructures 9 in each section 2a is formed in one piece of a material that has a refractive index of 1.67, corresponding to the refractive index of a plastic material at the wavelength of 940 nanometers of the light beam profile of incoming light 4.

[0162] Fig. 3 shows a schematic diagram of the transmitted normalized intensity of each of the 69 diffraction orders of the output light beam pattern 5. Each dot 7 in Fig. 1 corresponds to one bar 13 in Fig. 3. In Fig. 3, the horizontal axis refers to the horizontal dimension of the output light beam pattern 5. The horizontal coordinate of each diffraction order is denoted on the horizontal axis as diffraction order ranging from -4 to 4.

[0163] The dots 7 in the leftmost column in Fig. 1 have the horizontal coordinate denoted “-4” in Fig. 3. Since the leftmost column of dots 7 in Fig. 1 includes five dots 7, there are five vertical bars 13 in Fig. 3 centered around the horizontal coordinate “-4”. This applies accordingly for the remaining horizontal coordinates depicted in Fig. 3.

[0164] The height of a bar 13 in Fig. 3 corresponds to the transmitted normalized intensity of the respective diffraction order. The dashed horizontal lines 11 labelled + / - 5% indicate a 5% deviation of the intensities of the diffraction orders from the average intensity of the diffraction orders.

[0165] In the present embodiment, the uniformity of the intensities of the diffraction orders of the output light beam pattern 5 is less than 1%. Moreover, the transmitted intensity into all 69 diffraction orders is less than ±1% of the average intensity of the diffraction orders.

[0166] In the present embodiment, the transmission efficiency of the optical element 2 is 90%.

[0167] In the present embodiment, the positions and geometric parameters of the nanostructures 9 provided on a substrate body 8 of an optical element 2 are obtained by the computer-implemented method as described herein.

[0168] Fig. 4 schematically illustrates in a flow diagram an embodiment of a method 50 of manufacturing an optical element as described herein.

[0169] At 51, the optical element is formed by injection molding, wherein the optical element includes a substrate body and nanostructures protruding from the substrate body, wherein each nanostructure has a position on the substrate body and one or more geometric parameters including a height such that a light beam profile of incoming light having a predetermined wavelength is converted to an output light beam pattern, as discussed herein.Sony Semiconductor Solutions Corporation et al.

[0170] Fig. 5 schematically illustrates in a flow diagram an embodiment of a computer-implemented method 60.

[0171] The computer-implemented method 60 may be obtained by the information processing device as described herein.

[0172] At 61, data representing a light beam profile of incoming light, a predetermined wavelength of the light beam profile of incoming light and a target output light beam pattern is obtained, as discussed herein.

[0173] At 62, data representing geometric parameter ranges for nanostructures is obtained, as discussed herein.

[0174] At 63, a light propagation through an optical element having a substrate body and nanostructures protruding from the substrate body is simulated to obtain a simulated output light beam pattern, wherein the simulation is based on the light beam profile of incoming light and the predetermined wavelength as input, as discussed herein.

[0175] At 64, the position and the geometric parameters of each nanostructure, the geometric parameters including a height, are determined by minimizing a root mean square error, RMSE, given by

[0176]

[0177] wherein N is the number of diffraction orders of the target output light beam pattern and li is the intensity of the i-th diffraction order of the simulated output light beam pattern normalized by the average intensity Lnof the incoming light incident on the optical element, as discussed herein. Fig. 6 schematically illustrates in a flow diagram an embodiment of a computer-implemented method 70.

[0178] In the following, it is discussed how the concrete positions and geometric parameters of the nanostructures 9 of the optical element 2 of Fig. 2 are determined with a computer-implemented method such that the output light beam pattern 5 is generated when the light beam profile of incoming light 4 is incident. The output light beam pattern is based on a target output light beam pattern which is assumed in the optimization procedure and corresponds to an ideal case in which each diffraction order has the same intensity.Sony Semiconductor Solutions Corporation et al.

[0179] At 71, a target output light beam pattern, the wavelength of the light beam profile of incoming light 4, the refractive index of the material of the optical element 2, and the size of the section of the substrate body 8 within which the nanostructures 9 are determined.

[0180] In the present embodiment, the target output light beam pattern is a two-dimensional dot array that has 69 diffraction orders (see Fig. 1), the light beam profile of incoming light 4 has a wavelength of 940 nanometers, the refractive index of the material of the optical element 2 is 1.67, and the size of the section 2a of the substrate body 8 within which the nanostructures 9 are provided equals 4340 nanometers by 4340 nanometers.

[0181] At 72, a library of nanostructures 9 is generated for the predetermined wavelength of the light beam profile of incoming light 4 and the refractive index of the material of the optical element 2. The library provides information on the local phase change induced by a nanostructure as a function of the height 11 and diameter 12 of the nanostructure 9.

[0182] At 72, the ranges of the geometric parameters of the nanostructures 9 are further specified to ensure that the computer-implemented method yields physically feasible orders of magnitude of the geometric parameters of the nanostructures 9.

[0183] At 73, the number and geometric parameters, and positions of the nanostructures 9 on the substrate body 8 are determined for a one-dimensional spatial arrangement of the nanostructures 9 on the substrate body 8, involving a numerical simulation of the conversion of the light beam profile of incoming light 4 incident on the optical element 2 to a simulated output light beam pattern.

[0184] The numbers, geometric parameters, and positions of the nanostructures 9 are derived such that the root mean square error, i.e., the average deviation of the intensities of the diffraction orders of the simulated output light beam pattern from the intensities of the diffraction orders of the target output light beam pattern is minimized, wherein, in the present embodiment, the target output light beam pattern 5 is a two-dimensional dot array that has 69 diffraction orders (see Fig.

[0185] 1).

[0186] In the present embodiment, the nanostructures 9 have a cylindrical shape, and the geometric parameters comprise a diameter 12 and a height 11.

[0187] At 74, the number and heights of the nanostructures 9, as determined at 73, are selected and serve as input to 75.Sony Semiconductor Solutions Corporation et al.

[0188] At 75, the previously determined number and heights of the nanostructures 9 serve, along with the previously mentioned parameters, as input to the optimization process of a two-dimensional arrangement of nanostructures 9, which is, similar to 73, based on a numerical simulation.

[0189] The geometric parameters and the positions of the nanostructures 9 in the two-dimensional arrangement are derived by minimizing the average deviation, quantified by means of a root mean square error, of the intensities of the diffraction orders of the simulated output light beam pattern from the intensities of the diffraction orders of the target output light beam pattern.

[0190] In the present embodiment, the thereby derived root mean square error equals 10%.

[0191] Fig. 7 schematically illustrates in a block diagram an embodiment of a multi-purpose computer 30 which can be used for implementing an information processing device configured to perform the computer-implemented method as described herein.

[0192] The computer 30 can be implemented such that it can basically function as any type of information processing device as described herein. The computer has components 31 to 41, which can form a circuitry, such as any one of the circuitries of the information processing device as described herein.

[0193] Embodiments which use software, firmware, programs or the like for performing the methods as described herein can be installed on computer 30, which is then configured to be suitable for the concrete embodiment.

[0194] The computer 30 has a CPU 31 (Central Processing Unit), which can execute various types of procedures and methods as described herein, for example, in accordance with programs stored in a read-only memory (ROM) 32, stored in a storage 37 and loaded into a random-access memory (RAM) 33, stored on a medium 40 which can be inserted in a respective drive 39, etc.

[0195] The CPU 31, the ROM 32 and the RAM 33 are connected with a bus 41, which in turn is connected to an input / output interface 34. The number of CPUs, memories and storages is only exemplary, and the skilled person will appreciate that the computer 30 can be adapted and configured accordingly for meeting specific requirements which arise, when it functions as an information processing device.

[0196] At the input / output interface 34, several components are connected: an input 35, an output 36, the storage 37, a communication interface 38 and the drive 39, into which a medium 40 (compact disc, digital video disc, compact flash memory, or the like) can be inserted.Sony Semiconductor Solutions Corporation et al.

[0197] The input 35 can be a pointer device (mouse, graphic table, or the like), a keyboard, a microphone, a camera, a touchscreen, a time-of-flight device, etc.

[0198] The output 36 can have a display (liquid crystal display, cathode ray tube display, light emittance diode display, etc.), loudspeakers, etc.

[0199] The storage 37 can have a hard disk, a solid-state drive and the like.

[0200] The communication interface 38 can be adapted to communicate, for example, via a local area network (LAN), wireless local area network (WLAN), mobile telecommunications system (GSM, UMTS, LTE, NR etc.), Bluetooth, infrared, etc.

[0201] It should be noted that the description above only pertains to an example configuration of computer 30. Alternative configurations may be implemented with additional or other sensors, storage devices, interfaces or the like. For example, the communication interface 38 may support other radio access technologies than the mentioned UMTS, LTE and NR.

[0202] It should be recognized that the embodiments describe methods with an exemplary ordering of method steps. The specific ordering of method steps is however given for illustrative purposes only and should not be construed as binding.

[0203] In so far as the embodiments of the disclosure described above are implemented, at least in part, using software-controlled data processing apparatus, it will be appreciated that a computer program providing such software control and a transmission, storage or other medium by which such a computer program is provided are envisaged as aspects of the present disclosure.

[0204] Although the present disclosure has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Additionally, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognize that various features of the described embodiments may be combined in any manner suitable to implement the technique.

[0205] Note that the present technology can also be configured as described below.

[0206] (1) An optical element, including:

[0207] a substrate body; and

[0208] a metasurface consisting of nanostructures building patterns attached on top of the substrate body, wherein each nanostructure has a position on the substrate body and one or more geometric parameters including a height such that a light beam profile of incoming light having a predetermined wavelength is converted to an output light beam pattern.Sony Semiconductor Solutions Corporation et al.

[0209] (2) The optical element of (1), wherein the output light beam pattern has a plurality of diffraction orders, wherein a root mean square error, RMSE, given by

[0210] RMSE =

[0211]

[0212] is less than or equal to 10%, wherein N is the number of diffraction orders and li is the intensity of the i-th diffraction order normalized by the average intensity lin of the incoming light incident on the optical element.

[0213] (3) The optical element of (1) or (2), wherein the output light beam pattern has a plurality of diffraction orders, wherein a uniformity, given by

[0214] lmax“lniiii

[0215]

[0216] Imax+lniin

[0217] is less than or equal to 1%, wherein Imax is the intensity of a diffraction order with the highest intensity and Imin is the intensity of a diffraction order with the lowest intensity.

[0218] (4) The optical element of any one of (1) to (3), wherein the output light beam pattern has a plurality of diffraction orders, wherein a transmission efficiency, given by

[0219]

[0220] lin ’

[0221] is greater than or equal to 90%, wherein N is the number of diffraction orders, li is the intensity of the i-th diffraction order and lin is the average intensity of the incoming light incident on the optical element.

[0222] (5) The optical element of any one of (1) to (4), wherein the optical element includes a material that has a refractive index greater than or equal to 1.3 and less than or equal to 1.9 for the predetermined wavelength, and wherein the predetermined wavelength is greater than or equal to 300 nanometers and less than or equal to 2000 nanometers.

[0223] (6) The optical element of (5), wherein the material is a polymer material suitable for injection molding, in particular, the material is poly(methyl methacrylate), polystyrene, or polycarbonate.

[0224] (7) The optical element of any one of (1) to (6), wherein the field of view of the output light beam pattern is greater than 60 degrees.

[0225] (8) The optical element of any one of (1) to (7), wherein the output light beam pattern includes a line pattern or a dot pattern.Sony Semiconductor Solutions Corporation et al.

[0226] (9) The optical element of any one of (1) to (8), wherein the nanostructures are provided in a predetermined symmetry.

[0227] (10) The optical element of (9), wherein the nanostructures are provided in an axial symmetry for one-dimensional output light beam patterns, and in a fourfold rotational symmetry for two-dimensional output light beam patterns.

[0228] (11) The optical element of any one of (1) to (10), wherein each nanostructure has the same shape.

[0229] (12) The optical element of (11), wherein each nanostructure has a cylindrical shape.

[0230] (13) The optical element of (12), wherein each nanostructure has a diameter greater than or equal to 100 nanometers and less than or equal to 1000 nanometers.

[0231] (14) The optical element of (12) or (13), wherein the distance between any two nanostructures is greater than 100 nanometers.

[0232] (15) The optical element of any one of (12) to (14), wherein each nanostructure has an aspect ratio of less than 5:1, wherein the aspect ratio corresponds to the ratio of the height and the diameter, in particular, wherein each nanostructure has a height of less than 2.5 micrometers. (16) The optical element of any one of (1) to (15), wherein the geometric parameters and positions are determined according to the computer-implemented method of (20).

[0233] (17) The optical element of any one of (1) to (16), wherein the nanostructures are positioned according to sections of a periodic pattern, wherein each section includes a plurality of nanostructures such that, in each section, each nanostructure of the plurality of nanostructures has the same relative position and the same geometric parameters.

[0234] (18) A light beam pattern projector, including:

[0235] an optical element including:

[0236] a substrate body, and

[0237] a metasurface consisting of nanostructures building patterns attached on top of the substrate body, wherein each nanostructure has a position on the substrate body and one or more geometric parameters including a height such that a light beam profile of incoming light having a predetermined wavelength is converted to an output light beam pattern; and

[0238] a light source configured to emit the light beam profile incident on the optical element such that the optical element coverts the light beam profile to the output light beam pattern. (19) A method of manufacturing an optical element, including:Sony Semiconductor Solutions Corporation et al.

[0239] forming the optical element by injection molding, wherein the optical element includes:

[0240] a substrate body, and

[0241] a metasurface consisting of nanostructures building patterns attached on top of the substrate body, wherein each nanostructure has a position on the substrate body and one or more geometric parameters including a height such that a light beam profile of incoming light having a predetermined wavelength is converted to an output light beam pattern.

[0242] (20) A computer-implemented method, including:

[0243] obtaining data representing a light beam profile of incoming light, a predetermined wavelength of the light beam profile of incoming light and a target output light beam pattern with a target field-of-view;

[0244] obtaining data representing geometric parameter ranges for nanostructures; simulating a light propagation through an optical element having a substrate body and a metasurface consisting of nanostructures building patterns on top of the substrate body to obtain a simulated output light beam pattern, wherein the simulation is based on the light beam profile of incoming light and the predetermined wavelength as input; and

[0245] optimizing the position and the geometric parameters of each nanostructure, the geometric parameters including a height, by minimizing a root mean square error, RMSE, given by

[0246]

[0247] wherein N is the number of diffraction orders of the target output light beam pattern in accordance with the target field-of-view and L is the intensity of the i-th diffraction order of the simulated output light beam pattern normalized by the average intensity Im of the incoming light incident on the optical element.

[0248] (21) A computer program comprising program code causing a computer to perform the method according to (20), when being carried out on a computer.

[0249] (22) A non-transitory computer-readable recording medium that stores therein a computer program product, which, when executed by a processor, causes the method according to (20) to be performed.

Claims

Sony Semiconductor Solutions Corporation et al.CLAIMS1. An optical element, comprising:a substrate body; anda metasurface consisting of nanostructures building patterns attached on top of the substrate body, wherein each nanostructure has a position on the substrate body and one or more geometric parameters including a height such that a light beam profile of incoming light having a predetermined wavelength is converted to an output light beam pattern.

2. The optical element according to claim 1, wherein the output light beam pattern has a plurality of diffraction orders, wherein a root mean square error, RMSE, given byRMSE =is less than or equal to 10%, wherein N is the number of diffraction orders and li is the intensity of the i-th diffraction order normalized by the average intensity lin of the incoming light incident on the optical element.

3. The optical element according to claim 1, wherein the output light beam pattern has a plurality of diffraction orders, wherein a uniformity, given bylmax“lniiiiImax+lniinis less than or equal to 1%, wherein Imax is the intensity of a diffraction order with the highest intensity and Imin is the intensity of a diffraction order with the lowest intensity.

4. The optical element according to claim 1, wherein the output light beam pattern has a plurality of diffraction orders, wherein a transmission efficiency, given bylin ’is greater than or equal to 90%, wherein N is the number of diffraction orders, li is the intensity of the i-th diffraction order and lin is the average intensity of the incoming light incident on the optical element.

5. The optical element according to claim 1, wherein the optical element includes a material that has a refractive index greater than or equal to 1.3 and less than or equal to 1.9 for the predetermined wavelength, and wherein the predetermined wavelength is greater than or equal to 300 nanometers and less than or equal to 2000 nanometers.Sony Semiconductor Solutions Corporation et al.

6. The optical element according to claim 5, wherein the material is a polymer material suitable for injection molding, in particular, the material is poly(methyl methacrylate), polystyrene, or polycarbonate.

7. The optical element according to claim 1, wherein the field of view of the output light beam pattern is greater than 60 degrees.

8. The optical element according to claim 1, wherein the output light beam pattern includes a line pattern or a dot pattern.

9. The optical element according to claim 1, wherein the nanostructures are provided in a predetermined symmetry.

10. The optical element according to claim 9, wherein the nanostructures are provided in an axial symmetry for one-dimensional output light beam patterns, and in a fourfold rotational symmetry for two-dimensional output light beam patterns.

11. The optical element according to claim 1, wherein each nanostructure has the same shape.

12. The optical element according to claim 11, wherein each nanostructure has a cylindrical shape.

13. The optical element according to claim 12, wherein each nanostructure has a diameter greater than or equal to 100 nanometers and less than or equal to 1000 nanometers.

14. The optical element according to claim 12, wherein the distance between any two nanostructures is greater than 100 nanometers.

15. The optical element according to claim 12, wherein each nanostructure has an aspect ratio of less than 5:1, wherein the aspect ratio corresponds to the ratio of the height and the diameter, in particular, wherein each nanostructure has a height of less than 2.5 micrometers.

16. The optical element according to claim 1, wherein the geometric parameters and positions are determined according to the computer-implemented method of claim 20.

17. The optical element according to claim 1, wherein the nanostructures are positioned according to sections of a periodic pattern, wherein each section includes a plurality of nanostructures such that, in each section, each nanostructure of the plurality of nanostructures has the same relative position and the same geometric parameters.

18. A light beam pattern projector, comprising:an optical element including:a substrate body, andSony Semiconductor Solutions Corporation et al.a metasurface consisting of nanostructures building patterns attached on top of the substrate body, wherein each nanostructure has a position on the substrate body and one or more geometric parameters including a height such that a light beam profile of incoming light having a predetermined wavelength is converted to an output light beam pattern; anda light source configured to emit the light beam profile incident on the optical element such that the optical element coverts the light beam profile to the output light beam pattern.

19. A method of manufacturing an optical element, comprising:forming the optical element by injection molding, wherein the optical element includes:a substrate body, anda metasurface consisting of nanostructures building patterns attached on top of the substrate body, wherein each nanostructure has a position on the substrate body and one or more geometric parameters including a height such that a light beam profile of incoming light having a predetermined wavelength is converted to an output light beam pattern.

20. A computer-implemented method, comprising:obtaining data representing a light beam profile of incoming light, a predetermined wavelength of the light beam profile of incoming light and a target output light beam pattern with a target field-of-view;obtaining data representing geometric parameter ranges for nanostructures; simulating a light propagation through an optical element having a substrate body and a metasurface consisting of nanostructures building patterns attached on top of the substrate body to obtain a simulated output light beam pattern, wherein the simulation is based on the light beam profile of incoming light and the predetermined wavelength as input; andoptimizing the position and the geometric parameters of each nanostructure, the geometric parameters including a height, by minimizing a root mean square error, RMSE, given bywherein N is the number of diffraction orders of the target output light beam pattern in accordance with the target field-of-view and L is the intensity of the i-th diffraction order of the simulated output light beam pattern normalized by the average intensity Im of the incoming light incident on the optical element.

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