Laser radar transmitting system, scanning method and wafer-level packaging device

Abstract

The embodiment of the present application provides a laser radar transmission system, a scanning method and a wafer-level packaged device, which belongs to the technical field of laser radar. The system includes: a first superlens array, including a first superlens arranged in an array, and the first superlens is a Huygens superlens; a light-emitting array, including light-emitting units arranged in an array; the light-emitting array is arranged on the object focal plane of the first superlens array, and the light-emitting unit is used to generate a first light beam; the first light beam is a divergent laser whose main light is parallel to the optical axis of the first superlens array; an aperture array, including sub-apertures arranged in an array; the aperture array is arranged on the side of the first superlens array away from the light-emitting array; the first light beam is converted into a second light beam through the first superlens array and emitted from the aperture array; the second light beam is parallel light; wherein the relative position of the light-emitting array and the first superlens array in the direction perpendicular to the optical axis is adjustable. The simple structure of the system promotes the miniaturization of the laser radar transmission system.

Description

Technical Field

[0001] The present application relates to the technical field of laser radar, and specifically, to a laser radar transmitting system, a scanning method and a wafer-level packaged device. Background Art

[0002] Lidar (Light Detection And Ranging) is a technology that detects the position, speed and other characteristic quantities of a target by emitting lasers and receiving laser echo signals. The Lidar transmitting system is one of the core components of Lidar. Generally, the Lidar transmitting system includes a laser light source and a corresponding optical system.

[0003] Among the existing laser radar transmission systems, there is a method that uses a micro-electromechanical system (MEMS) reflector to change the emission angle of the laser beam to achieve the scanning of the laser beam on the far-field detection target. The laser radar adopting this design concept requires the MEMS reflector to scan the stationary point regardless of one-dimensional scanning or two-dimensional scanning.

[0004] The vertical scanning range of the laser radar transmitting system with this structure depends on the number of laser paths, and the horizontal scanning angle depends on the scanning range of the MEMS reflector. That is, the more laser paths there are, the larger the vertical scanning range is; the more the angle of the MEMS reflector changes, the more the laser scanning angle changes.

[0005] However, due to the presence of MEMS mirrors, this structure has complex structure and optical path, high cost and is difficult to adapt to the market's increasingly stringent requirements for miniaturization, lightweight, simplicity and low cost of lidar. Summary of the invention

[0006] In order to solve the problem in the prior art that the scanning range of the laser radar transmitting system is limited by the MEMS reflective galvanometer, the embodiments of the present application provide a laser radar transmitting system, a scanning method and a wafer-level packaged device.

[0007] In a first aspect, an embodiment of the present application provides a laser radar transmission system, characterized in that the system includes:

[0008] A first superlens array, comprising at least one first superlens arranged in an array, wherein the first superlens is a Huygens superlens;

[0009] A light-emitting array, comprising at least one light-emitting unit arranged in an array; the light-emitting array is arranged on the object focal plane of the first super lens array, and the light-emitting unit is used to generate a first light beam; the first light beam is a divergent laser whose main ray is parallel to the optical axis of the first super lens array;

[0010] An aperture array, comprising at least one sub-aperture arranged in an array; the aperture array is arranged on a side of the first super lens array away from the light-emitting array; the first light beam is converted into a second light beam by the first super lens array and emitted from the aperture array; the second light beam is parallel light;

[0011] Wherein, the relative positions of the light-emitting array and the first super lens array in a direction perpendicular to the optical axis are adjustable.

[0012] Optionally, the system further satisfies:

[0013] Δθ=arctan(Δd / L);

[0014] Among them, Δd is the relative displacement between the first super lens array and the light emitting array in the direction perpendicular to the optical axis; L is the distance between the aperture array and the first super lens array; Δθ is the rotation angle of the second light beam after the first super lens array and the light emitting array produce relative displacement in the direction perpendicular to the optical axis.

[0015] Optionally, the light emitting unit includes a point light source and a focus of a converging laser;

[0016] The convergent laser forms the first light beam after passing through the focus.

[0017] Optionally, the system further comprises a converging device array; the converging device array comprises at least one sub-converging device arranged in an array; the converging device array is arranged upstream of the first super lens array, and is used to converge the incident laser to at least one of the focal points;

[0018] The sub-converging device includes a spherical refractive lens, an aspherical refractive lens or a second super lens.

[0019] Optionally, the system further comprises a micro-electromechanical system; the micro-electromechanical system is configured to adjust the displacement of the light-emitting array and / or the first super-lens array along a direction perpendicular to the optical axis.

[0020] Optionally, a driving stroke of the micro-electromechanical system is less than or equal to 10 mm.

[0021] Optionally, a driving accuracy of the micro-electromechanical system is greater than or equal to 1 micron and less than or equal to 5 microns.

[0022] Optionally, the operating frequency of the micro-electromechanical system is greater than 1 kHz.

[0023] Optionally, the system further comprises a wavefront controller; the wavefront controller is arranged at an entrance pupil of the converging device array;

[0024] The wavefront controller is used to adjust the focal position of the focusing device array.

[0025] Optionally, the wavefront controller includes a spatial light modulator, a digital micro-mirror array, or an adjustable metasurface spatial light modulator.

[0026] Optionally, the first superlens and the second superlens each include a substrate and a nanostructure layer disposed on the substrate;

[0027] The nanostructure layer includes nanostructures arranged in an array.

[0028] Optionally, the nanostructure layer includes superstructure units arranged in an array;

[0029] The superstructure unit is a densely packed figure; the nanostructure is arranged at the center position and / or the vertex position of the densely packed figure.

[0030] Optionally, the metalens further comprises a filling material;

[0031] The filling material is filled between the nanostructures.

[0032] Optionally, an absolute value of a difference between a refractive index of the filling material and a refractive index of the nanostructure is greater than or equal to 0.5.

[0033] Optionally, the period of the superstructure unit is greater than or equal to 0.3λ c , and less than or equal to 2λ c ;

[0034] Among them, λ c is the central wavelength of the operating band of the system.

[0035] Optionally, the height of the nanostructure is greater than or equal to 0.3λ c , and less than or equal to 5λ c ;

[0036] Among them, λ c is the central wavelength of the operating band of the system.

[0037] Optionally, the shape of the nanostructure includes a polarization sensitive structure.

[0038] Optionally, the shape of the nanostructure includes a polarization insensitive structure.

[0039] Optionally, the metalens further includes an anti-reflection film;

[0040] The anti-reflection film is arranged on a side of the substrate and the nanostructure layer adjacent to the air.

[0041] Optionally, the phase of the first metalens at least satisfies:

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048] Wherein, r is the distance from the center of the first super lens to the center of any of the nanostructures; λ is the operating wavelength, is any phase related to the working wavelength, x, y are the mirror coordinates of the first superlens, and f is the focal length of the first superlens.

[0049] In a second aspect, an embodiment of the present application further provides a laser radar scanning method, which is applicable to a laser radar transmitting system provided in any of the above embodiments, and the method includes:

[0050] The light-emitting array, the first super lens array and the aperture array are arranged in sequence along the laser emission direction; the first light beam generated by the light-emitting array is converted into a second light beam by the first super lens array and emitted from the sub-aperture; the first light beam is a divergent laser whose main ray is parallel to the optical axis of the first super lens; the second light beam is a parallel light;

[0051] The relative positions of the light emitting array and the first super lens array in a direction perpendicular to the optical axis are adjusted so that the emission angle of the second light beam is rotated.

[0052] Optionally, the relative position satisfies:

[0053] Δx=Ltan(θ x );

[0054] Δz=L tan(θ z );

[0055] Wherein, x is a first direction perpendicular to the optical axis, z is a second direction perpendicular to the optical axis, and the x direction is perpendicular to the z direction; L is a distance between the aperture array and the first super lens array; θ is a rotation angle of the second light beam emitted through the aperture array.

[0056] Optionally, the light emitting array, the first super lens array and the aperture array are all two-dimensional arrays;

[0057] The relative positions of the light emitting array and the first super lens array in a direction perpendicular to the optical axis are adjusted so that the second light beam rotates in a two-dimensional scanning form.

[0058] Optionally, the light emitting array, the first super lens array and the aperture array are all one-dimensional arrays;

[0059] The relative positions of the light emitting array and the first super lens array in a direction perpendicular to the optical axis are adjusted so that the second light beam rotates in a one-dimensional scanning form.

[0060] In a third aspect, an embodiment of the present application further provides a wafer-level packaged device, characterized in that it is applicable to a laser radar transmitting system provided in any of the above embodiments, and the wafer-level packaged device includes:

[0061] The light emitting array includes an array of light sources disposed on a focal plane of the array of converging devices; and

[0062] A first spacing layer is disposed between the converging device array and the light source array, and a height of the first spacing layer is equal to a focal length of the converging device array;

[0063] The first super lens array is arranged on a side of the converging device array away from the light source array; and the object-side focal plane of the first super lens array coincides with the focal plane of the converging device array;

[0064] A second spacing side is provided on a side of the first super lens array away from the focusing device array, and is used to support the aperture array;

[0065] Furthermore, the light-emitting array and / or the first super lens array are arranged on a displacement platform to achieve relative displacement of the light-emitting array and the first super lens array.

[0066] The laser radar transmitting system provided in the embodiment of the present application forms an object-side telecentric system through the first super lens array and the aperture array, and realizes the deflection of the second light beam by virtue of the relative displacement of the light emitting array and the first super lens array in the direction perpendicular to the optical axis. The system omits the MEMS reflective galvanometer, has a streamlined structure, and a simple optical path, which is conducive to the miniaturization and lightweight of the laser radar transmitting system. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] The accompanying drawings are included to provide a further understanding of the present application and are incorporated in and constitute a part of this specification. The accompanying drawings illustrate embodiments of the present application and together with the following description serve to explain the principles of the present application.

[0068] Figure 1An optional structural schematic diagram of a laser radar transmitting system provided in an embodiment of the present application is shown;

[0069] Figure 2 Another optional structural schematic diagram of the laser radar transmitting system provided in the embodiment of the present application is shown;

[0070] Figure 3 Another optional structural schematic diagram of the laser radar transmitting system provided in the embodiment of the present application is shown;

[0071] Figure 4 Another optional structural schematic diagram of the laser radar transmitting system provided in the embodiment of the present application is shown;

[0072] Figure 5 Another optional structural schematic diagram of the laser radar transmitting system provided in the embodiment of the present application is shown;

[0073] Figure 6 An optional structural schematic diagram of a sub-convergence device provided in an embodiment of the present application is shown;

[0074] Figure 7 A schematic diagram showing another optional structure of the sub-convergence device provided in an embodiment of the present application is shown;

[0075] Figure 8 A schematic diagram showing another optional structure of the sub-convergence device provided in an embodiment of the present application is shown;

[0076] Fig. 9 A schematic diagram showing another optional structure of the sub-convergence device provided in an embodiment of the present application is shown;

[0077] Fig.10 An optional structural schematic diagram of a metalens provided in an embodiment of the present application is shown;

[0078] Fig.11 An optional structural schematic diagram of the nanostructure provided in the embodiment of the present application is shown;

[0079] Fig.12 Another optional structural schematic diagram of the nanostructure provided in the embodiment of the present application is shown;

[0080] Fig.13 An optional structural diagram of a superstructure unit provided in an embodiment of the present application is shown;

[0081] Fig.14 Another optional structural diagram of the superstructure unit provided in the embodiment of the present application is shown;

[0082] Fig.15Another optional structural diagram of the superstructure unit provided in the embodiment of the present application is shown;

[0083] Fig.16 A diagram showing the relationship between transmittance and phase modulation of an optional nanostructure provided in an embodiment of the present application is shown;

[0084] Fig.17 An optional schematic diagram of a laser radar scanning method provided in an embodiment of the present application is shown;

[0085] Fig.18 Another optional schematic diagram of the laser radar scanning method provided in the embodiment of the present application is shown;

[0086] Fig.19 An optional structural schematic diagram of a wafer-level packaged device provided in an embodiment of the present application is shown;

[0087] Fig. 20 Another optional structural schematic diagram of a wafer-level packaged device provided in an embodiment of the present application is shown;

[0088] Fig.21 An optional phase diagram of the spatial light modulator provided in an embodiment of the present application is shown;

[0089] Fig. 22 Another optional phase diagram of the spatial light modulator provided in the embodiment of the present application is shown.

[0090] The reference numerals in the figure represent respectively:

[0091] 10-first metalens array; 20-light emitting array; 30-aperture array; 40-converging device array; 50-wavefront controller; 60-adjustable focus optical system;

[0092] 101 - first super lens; 201 - light emitting unit; 301 - sub-aperture; 401 - sub-converging device. DETAILED DESCRIPTION

[0093] The present application will now be described more fully below with reference to the accompanying drawings, in which various embodiments are shown. However, the present application can be implemented in many different ways and should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that the present application will be exhaustive and complete, and will fully convey the scope of the present application to those skilled in the art. The same reference numerals throughout the text represent the same components. Furthermore, in the accompanying drawings, the thickness, ratios, and sizes of the components are exaggerated for clarity.

[0094] The terms used herein are only used for the purpose of describing specific embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, "one", "the", "at least one" as used herein do not represent a limitation on quantity, but are intended to include both the singular and the plural. For example, unless the context clearly indicates otherwise, "a component" has the same meaning as "at least one component". "At least one" should not be interpreted as being limited to the number "one". "Or" means "and / or". The term "and / or" includes any and all combinations of one or more of the associated listed items.

[0095] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meanings as those generally understood by those skilled in the art. Terms defined in commonly used dictionaries should be interpreted as having the same meanings as in the relevant technical context, and unless explicitly defined in the specification, these terms are not interpreted as having formal meanings in an idealized or overly formal sense.

[0096] The meaning of “include” or “comprising” specifies properties, quantities, steps, operations, components, parts or a combination thereof, but does not exclude other properties, quantities, steps, operations, components, parts or a combination thereof.

[0097] Embodiments are described herein with reference to cross-sectional views as idealized embodiments. Thus, variations in shape relative to the illustrated diagram are anticipated as a result of, for example, manufacturing techniques and / or tolerances. Therefore, the embodiments described herein should not be interpreted as being limited to the specific shapes of the regions as shown herein, but should include deviations in shape due to, for example, manufacturing. For example, a region shown or described as flat may typically have rough and / or nonlinear features. Moreover, the sharp angles shown may be rounded. Therefore, the regions shown in the figures are schematic in nature, and their shapes are not intended to illustrate the precise shape of the regions and are not intended to limit the scope of the claims.

[0098] Hereinafter, exemplary embodiments according to the present application will be described with reference to the accompanying drawings.

[0099] The present application embodiment provides a laser radar transmission system, such as Figures 1 to 5 As shown, the laser radar transmitting system includes a first super lens array 10, a light emitting array 20 and an aperture array 30.

[0100] The light emitting array 20 is arranged on one side of the first super lens array 10, and the aperture array 30 is arranged on the other side of the first super lens array 10, and the relative position of the light emitting array 20 and the first super lens array 10 in a direction perpendicular to the optical axis is adjustable.

[0101] Specifically, the aperture array 30 is located in the image space of the first super lens array 10 and is arranged on the same optical axis as the first super lens array 10 to form an object telecentric system. The first light beam generated by the light emitting array 20 is modulated by the first super lens array 10 to form a second light beam emitted from the aperture array 30. The first light beam is a divergent laser whose main light is parallel to the optical axis of the first super lens array 10. The second light beam is parallel light. Optionally, the distance between the aperture array 30 and the first super lens array 10 is less than or equal to one times the focal length of the first super lens array 10.

[0102] refer to Figure 2 Due to the characteristics of the telecentric system, if the light-emitting array 20, the first super lens array 10 and the aperture array 30 are arranged on the same optical axis, the second light beam is parallel to the optical axis of the first super lens array 10; if the optical axes of the light-emitting array 20 and the first super lens array 10 do not coincide, the second light beam is deflected. For example, when the position of the first super lens array 10 is fixed, when the light-emitting array 20 is displaced in any direction perpendicular to the optical axis of the first super lens array 10, the second light beam is deflected in the direction opposite to the displacement direction. For another example, when the position of the light-emitting array 20 is fixed, when the combination of the first super lens array 10 and the aperture array 30 is displaced in any direction perpendicular to the optical axis of the light-emitting array 20, the second light beam is deflected in the same direction as the displacement. By adjusting the relative displacement between the light-emitting array 20 and the first super lens array 10 in the direction perpendicular to the optical axis, the second light beam is deflected, thereby realizing the scanning of the second light beam.

[0103] It should be noted that, in order to ensure the parallelism of the second light beam, the principal ray of the first light beam needs to be parallel to the optical axis direction of the first super lens array 10 .

[0104] According to an embodiment of the present application, optionally, the laser radar transmitting system further satisfies:

[0105] Δθ=arctan(Δd / L); (1)

[0106] In formula (1), Δd is the relative displacement between the first super lens array 10 and the light emitting array 20 in the direction perpendicular to the optical axis; L is the distance between the aperture array 30 and the first super lens array 10; Δθ is the rotation angle of the second light beam after the first super lens array 10 and the light emitting array 20 generate relative displacement in the direction perpendicular to the optical axis.

[0107] According to the implementation mode of this application, Figures 1 to 5As shown, the first superlens array 10 includes at least one first superlens 101 arranged in an array, and the first superlens 101 is a Huygens superlens. The Huygens superlens is a superlens based on the Huygens equivalent principle, characterized in that the angle between the main ray angle and the optical axis is less than or equal to 8°. By designing the phase of the Huygens superlens, the incident light beam can be deflected in a predetermined manner. According to the embodiment of the present application, Figure 2 As shown, the first light beam is modulated by the first super lens 101 to form a second light beam. According to an embodiment of the present application, the light-emitting array 20 includes at least one light-emitting unit 201 arranged in an array. The light-emitting array 20 is arranged on the object focal plane of the first super lens array 10. The light-emitting array 20 is used to generate a first light beam. Optionally, the light-emitting unit 201 includes a point light source and a focus of a converging laser. Preferably, the light-emitting unit 201 adopts the focus of a converging laser. According to an embodiment of the present application, the aperture array 30 includes at least one sub-aperture 301 arranged in an array. Preferably, the sub-aperture 301 corresponds to the first super lens 101 one-to-one, so that any first super lens 101 and the corresponding sub-aperture 301 constitute an object telecentric system.

[0108] According to the implementation mode of this application, Figure 3 and Figure 4 As shown, when the light emitting unit 201 is the focus of the convergent laser, the laser radar transmitting system also includes a convergent device array 40. The convergent device array 40 includes at least one sub-convergent device 401 arranged in an array. The convergent device array 40 is used to converge the parallel or approximately parallel laser light generated by the laser light source to the focus to form the light emitting array 20. The convergent laser forms a divergent first light beam after passing through the focus. Preferably, the focus of the convergent laser is located on the object focal plane of the first super lens array 10.

[0109] According to the implementation mode of this application, Figure 3 As shown, the converging device array 40 is an array of refractive lenses. In some embodiments, the refractive lenses are spherical lenses. Preferably, since aspherical lenses have better spherical aberration control than spherical lenses, the converging device array 40 uses aspherical refractive lenses to reduce the spot size of the focus as much as possible.

[0110] According to the implementation mode of this application, Figure 4 As shown, the converging device array 40 includes second metalenses arranged in an array. Any second metalenses can focus incident parallel light onto the object focal plane of the corresponding first metalenses 101 without spherical aberration. Compared with the refractive lens, the second metalenses are thinner and have no spherical aberration.

[0111] In any of the above embodiments, the relative displacement of the light emitting array 20 and the first super lens array 10 is achieved by means of a micro-electro-mechanical system (MEMS), and the micro-electro-mechanical system is configured to adjust the displacement of the light emitting array 20 and / or the first super lens array 10 in a direction perpendicular to the optical axis. Exemplarily, the micro-electro-mechanical system includes a MEMS flexible suspension. The MEMS flexible suspension is coupled to the converging device array 40, the point light source or the first super lens array 10, and the MEMS flexible suspension is configured to elastically deform in a direction perpendicular to the optical axis. Exemplarily, the driving stroke of the micro-electro-mechanical system is less than or equal to 10 mm. Preferably, the driving accuracy of the micro-electro-mechanical system is greater than or equal to 1 micron and less than or equal to 5 microns. Optionally, the operating frequency of the micro-electro-mechanical system is greater than 1 kHz.

[0112] Furthermore, if Figures 6 to 9 As shown, the laser radar transmitting system provided in the embodiment of the present application further includes a wavefront controller 50. The wavefront controller 50 is arranged at the entrance pupil of the converging device array 40 and is used to adjust the focal position of the converging device array 40. Figure 5 As shown, the focusing device array 40 and the wavefront controller 50 constitute an adjustable focus optical system.

[0113] Optionally, the wavefront controller 50 includes an array-arranged spatial light modulator (SLM), a digital micromirror array (DMD), or an adjustable metasurface spatial light modulator. Optionally, the wavefront controller can be a unit corresponding to multiple sub-converging devices. Optionally, the wavefront controller is in the form of an array, wherein each wavefront control unit is mapped one-to-many with the sub-converging device 401 in the converging device array 40. Optionally, the wavefront controller is in the form of an array, wherein each wavefront control unit is mapped one-to-one with the sub-converging device 401 in the converging device array 40.

[0114] According to the implementation mode of this application, Figure 6 As shown, the sub-converging device 401 is a microscope objective lens, and the wavefront controller 50 is located at the entrance pupil of the microscope objective lens. Figure 7 , the sub-converging device 401 is a mirror group composed of a refractive lens, and the wavefront controller 50 is located at the entrance pupil of the mirror group. In some exemplary embodiments, the sub-converging device 401 is a second super lens. In some other exemplary embodiments, the sub-converging device 401 is a mirror group composed of a second super lens and a refractive lens.

[0115] Next, combine Figures 10 to 16, the first superlens and the second superlens provided in the embodiments of the present application are described in detail. The superlens is a specific application of a supersurface, which modulates the phase, amplitude and polarization of incident light through periodically arranged sub-wavelength nanostructures.

[0116] Fig.10 FIG. 1 shows an optional structural diagram of a metalens provided in an embodiment of the present application. Fig.10 The first super lens and the second super lens both include a base layer and a nanostructure layer disposed on the base layer, wherein the nanostructure layer includes periodically arranged nanostructures.

[0117] According to an embodiment of the present application, optionally, in the nanostructure layer, the arrangement period of the nanostructures is greater than or equal to 0.3λ c , and less than or equal to 2λ c ; Among them, λ c is the center wavelength of the operating band.

[0118] According to an embodiment of the present application, optionally, the height of the nanostructures in the nanostructure layer is greater than or equal to 0.3λ c , and less than or equal to 5λ c ; Among them, λ c is the center wavelength of the operating band.

[0119] Fig.11 and Fig.12 A perspective view of a nanostructure in a metalens is shown. Optionally, Fig.11 The nanostructure is a cylindrical structure. Optionally, Fig.12 The nanostructure in is a square columnar structure. Fig.11 and Fig.12 As shown, the metalens also includes a filler, which is filled between the nanostructures, and the extinction coefficient of the filler material for the working band is less than 0.01. Optionally, the filler includes air or other materials that are transparent or translucent in the working band. According to an embodiment of the present application, the absolute value of the difference between the refractive index of the filler material and the refractive index of the nanostructure should be greater than or equal to 0.5.

[0120] In some optional embodiments of the present application, Figures 13 to 15 As shown, the nanostructure layer includes superstructure units arranged in an array. The superstructure unit is a densely packed figure, and the vertex and / or center position of the densely packed figure is provided with a nanostructure. In the embodiment of the present application, the densely packed figure refers to one or more figures that can fill the entire plane without gaps or overlaps.

[0121] like Fig.13 As shown, according to the embodiment of the present application, the superstructure units can be arranged in a fan shape. Fig.14As shown, according to the embodiment of the present application, the superstructure units can be arranged in a regular hexagonal array. Fig.15 As shown, according to the embodiment of the present application, the superstructure units can be arranged in a square array. Those skilled in the art should recognize that the superstructure units included in the nanostructure layer can also include other forms of array arrangements, and all these variations are included in the scope of the present application.

[0122] Exemplarily, the nanostructure provided in the embodiment of the present application can be a polarization-independent structure, which applies a propagation phase to the incident light. According to the implementation of the present application, the nanostructure can be a positive structure or a negative structure. For example, the shape of the nanostructure includes a cylinder, a hollow cylinder, a square prism, a hollow square prism, etc.

[0123] Exemplarily, the shape of the nanostructure includes a cylinder, a hollow cylinder, a square column and a hollow square column. Optionally, the nanostructure is arranged at the center of the superstructure unit. In an optional embodiment of the present application, the shape of the nanostructure includes a cylinder, a hollow cylinder, a square column and a hollow square column. Optionally, the nanostructure is arranged at the center of the superstructure unit.

[0124] According to an embodiment of the present application, the shape of the nanostructure includes a cylinder, a hollow cylinder, a square cylinder and a hollow square cylinder. Optionally, the nanostructure is a negative nanostructure, such as a square hole cylinder, a circular hole cylinder, a square ring cylinder and a circular ring cylinder.

[0125] In an optional embodiment, if Fig.10 As shown, the metalens provided in the embodiment of the present application further includes an anti-reflection film. The anti-reflection film is disposed on the side of the substrate layer away from the nanostructure layer; or, the anti-reflection film is disposed on the side of the nanostructure layer adjacent to the air. The function of the anti-reflection film is to increase the transmittance and reduce the reflection of the incident radiation.

[0126] According to an embodiment of the present application, the material of the nanostructure is a material having an extinction coefficient of less than 0.01 for the working band. For example, the material of the nanostructure includes fused quartz, quartz glass, crown glass, flint glass, sapphire, crystalline silicon, amorphous silicon and hydrogenated amorphous silicon. For another example, when the working band of the superlens is the near-infrared band, the material of the nanostructure includes one or more of silicon nitride, titanium oxide, gallium nitride, gallium phosphide, hydrogenated amorphous silicon, amorphous silicon and crystalline silicon. For another example, when the working band of the superlens is the visible light band, the material of the nanostructure includes fused quartz, quartz glass, crown glass, flint glass, sapphire and alkaline glass. For another example, when the working band of the superlens is the far-infrared band, the material of the nanostructure includes one or more of crystalline silicon, crystalline germanium, zinc sulfide and zinc selenide.

[0127] For example, the material of the substrate layer includes fused quartz, quartz glass, crown glass, flint glass, sapphire, crystalline silicon, amorphous silicon and hydrogenated amorphous silicon. For another example, when the operating band of the superlens is the near-infrared band, the material of the substrate layer includes one or more of silicon nitride, titanium oxide, gallium nitride, gallium phosphide, hydrogenated amorphous silicon, amorphous silicon and crystalline silicon. For another example, when the operating band of the superlens is the visible light band, the material of the substrate layer includes fused quartz, quartz glass, crown glass, flint glass, sapphire and alkaline glass. For another example, when the operating band of the superlens is the far-infrared band, the material of the substrate layer includes one or more of crystalline silicon, crystalline germanium, zinc sulfide and zinc selenide.

[0128] In some embodiments of the present application, the material of the nanostructure is the same as the material of the base layer. In some other embodiments of the present application, the material of the nanostructure is different from the material of the base layer. Optionally, the material of the filler is the same as the material of the base layer. Optionally, the material of the filler is different from the material of the base layer.

[0129] It should be understood that in some optional embodiments of the present application, the filler and the nanostructure are made of different materials. Exemplarily, the material of the filler is a high-transmittance material in the working band, and its extinction coefficient is less than 0.01. Exemplarily, the material of the filler includes fused quartz, quartz glass, crown glass, flint glass, sapphire, crystalline silicon, amorphous silicon and hydrogenated amorphous silicon.

[0130] According to an embodiment of the present application, the phase of each first super lens 101 in the first super lens array 10 satisfies at least one of the following formulas (2-1) to (2-6):

[0131]

[0132]

[0133]

[0134]

[0135]

[0136]

[0137] Wherein, r is the distance from the center of the first superlens 101 to the center of any of the nanostructures; λ is the operating wavelength, is any phase related to the working wavelength, x, y are the mirror coordinates of the first superlens, and f is the focal length of the first superlens.

[0138] The phase of the metalens can be expressed by a high-order polynomial, which includes odd-order polynomials and even-order polynomials. In order not to destroy the rotational symmetry of the metalens phase, usually only the phase corresponding to the even-order polynomial can be optimized, which greatly reduces the design freedom of the metalens. Among the above formulas (2-1) to (2-6), formula (2-3) and formula (2-4) can optimize the phase that satisfies the odd-order polynomial without destroying the rotational symmetry of the metalens phase, thereby greatly improving the optimization freedom of the metalens.

[0139] Fig.16 The figure shows the relationship between the transmittance, phase and size of an optional nanostructure provided in the embodiment of the present application. Figure 6 As shown, when a cylindrical nanostructure is used, a suitable diameter of the nanocolumn can be selected according to the transmittance and phase required by the design.

[0140] In a second aspect, the present application also provides a laser radar scanning method, such as Fig.17 and Fig.18 As shown, it is applicable to the laser radar transmitting system provided by any of the above embodiments. The method comprises the following steps:

[0141] The light-emitting array 20, the first super lens array 10 and the aperture array 30 are arranged in sequence along the laser emission direction; the first light beam generated by the light-emitting array 20 is converted into a second light beam by the first super lens array 10 and emitted from the aperture array 30; the first light beam is a divergent laser whose main ray is parallel to the optical axis of the first super lens array 10; the second light beam is a parallel light;

[0142] The relative positions of the light emitting array 20 and the first super lens array 10 in a direction perpendicular to the optical axis are adjusted so that the emission angle of the second light beam is rotated.

[0143] According to the implementation mode of this application, Fig.17 As shown, the method is a two-dimensional array scan. Fig.17 As shown, the light array 20, the first super lens array 10 and the aperture array 30 are two-dimensional arrays, so that the second light beam forms a two-dimensional dot matrix in the far field. By adjusting the relative position of the light array 20 and the first super lens array 10, the two-dimensional array formed by the second light beam moves within the field of view. For example, Fig.17 FIG. 4 shows a schematic diagram of a two-dimensional array completing full-field scanning in a Z-shaped scanning manner within the field of view. Fig.17 Medium θ H represents the rotation angle of the second beam along the horizontal direction, θ V represents the rotation angle of the second light beam along the vertical direction. According to the embodiment of the present application, in the method, the relative positions of the light emitting array 20 and the first super lens array 10 satisfy formula (1).

[0144] In another optional embodiment, Fig.18 As shown, the method is a one-dimensional array scan. Fig.18 As shown, the light emitting array 20, the first super lens array 10 and the aperture array 30 are a one-dimensional array, so that the second beam formation can cover θ in the vertical direction. V By controlling the relative displacement of the light emitting array 20 and the first super lens array 10 in the horizontal direction, the one-dimensional array of the second light beam is deflected in the horizontal direction and covers θ H , thus achieving full field of view scanning. Based on a similar principle, the second beam covers θ in the horizontal direction. H By adjusting the relative displacement between the light emitting array 20 and the first super lens array 10 in the vertical direction, full field scanning can also be achieved.

[0145] In this method, the relative positions of the light emitting array 20 and the first super lens array 10 in the direction perpendicular to the optical axis satisfy:

[0146] Δx=Ltan(θ x ); (3-1)

[0147] Δz=L tan(θ z ); (3-2)

[0148] Wherein, x is a first direction perpendicular to the optical axis, z is a second direction perpendicular to the optical axis, and the x direction is perpendicular to the z direction; L is a distance between the aperture array 30 and the first super lens array 10; θ is a rotation angle of the second light beam emitted through the aperture array 30.

[0149] Any of the above methods can achieve accurate and high-speed scanning through electronically controlled devices such as one-dimensional and / or two-dimensional MEMS actuators or displacement actuators.

[0150] It should be noted that the metalens provided in the embodiment of the present application can be processed by semiconductor technology, and has the advantages of light weight, thin thickness, simple structure and process, low cost and high consistency in mass production. In view of this, the embodiment of the present application also provides a wafer-level packaged device.

[0151] In an alternative embodiment, see Fig.19 and Fig. 20In the wafer-level packaged device, the light emitting array 20 is a focal array, which is formed by focusing the light generated by the light source array by the converging device array 40. Optionally, the light source array includes a vertical cavity surface emitting laser (VCSEL) and an edge emitting laser (EEL). Fig.19 and Fig. 20 As shown, the converging device array 40 is a second super lens array. The light source array is arranged on the wafer base, and the second super lens array is supported by the first spacer layer to form a first assembly. The height of the first spacer layer is equal to the focal length of the second super lens. Preferably, the first spacer layer is opaque to the working band. Preferably, a single light source in the light source array corresponds one-to-one to a single super lens in the second super lens array, and the light source is located at the focus of the second super lens.

[0152] like Fig.19 and Fig. 20 As shown, the aperture array 30 is connected to the first super lens array 10 through a second spacer layer to form a second assembly. The second assembly is independent of the first assembly, and the first super lens array is located on the side of the focus array away from the second super lens array.

[0153] The first assembly and / or the second assembly is arranged on a displacement platform, and the first assembly and the second assembly are relatively displaced by the displacement platform, so that the first super lens array 10 and the light-emitting array (ie, the focal array) are relatively displaced.

[0154] Example 1

[0155] Embodiment 1 provides a 2x2 laser radar transmitting system, the operating band of which is at 1550nm. The first super lens array is a 2x2 array, the light emitting array is a 2x2 converging laser focus array, the aperture array 30 is correspondingly a 2x2 array, and the aperture array 30 is 2mm away from the first super lens array 10. The half field angle of a single first super lens is 42°, the focal length is 2mm, and the diameter is 3.6mm. The preset field of view to be scanned is 80°×30°, so for the laser radar transmitting system, the transmitting unit composed of a single light emitting unit, a single first super lens and a single aperture has a maximum exit half field angle of 41.4°, so as to cover the field of view to be scanned. The relative displacement of the light emitting array 20 and the first super lens array 10 in the laser radar transmitting system and the corresponding exit angle of the second light beam and the parallelism of the second light beam are shown in Table 1. In Table 1, the y-axis is the optical axis, and the x-axis and the z-axis are two directions perpendicular to the optical axis. x is the horizontal direction and z is the vertical direction.

[0156] Table 1

[0157]

[0158]

[0159] Example 2

[0160] Embodiment 2 provides a 1x31 one-dimensional column scanning laser radar transmission system, the working band is located at 1550nm. The parameters of the single first super lens are the same as the first super lens in Embodiment 1. The laser radar transmission system in Embodiment 2 is based on Fig.18 In the method, the angle between the optical axes of two adjacent light-emitting units is preset to 1° according to formulas (3-1) and (3-2). 801 angle points are preset in the z direction, and the interval between two adjacent angle points is 0.1°. The laser radar transmission system has a depth image imaging frequency of 60 images per second, and the scanning frequency must be greater than 48060 times / second. The corresponding one-dimensional nano-displacement platform has a motion frequency of 48.06Hz.

[0161] Example 3

[0162] Embodiment 3 provides a laser radar transmitting system, the working band is at 1550nm. The laser radar transmitting system also includes a wavefront controller 50. The parameters of a single first super lens in the system are as shown in Embodiment 1. In the converging device array 40 matched with the wavefront controller 50, any sub-converging device 401 has an entrance pupil diameter of 5mm, a focal length of 10mm, an object field of view of 4mm, and good focusing in the 1550nm band.

[0163] According to an embodiment of the present application, the wavefront controller is located at the entrance pupil of the focusing optical system, wherein the relationship between the adjustable focal position and the phase at the entrance pupil is as shown in formula (4):

[0164]

[0165] In the formula, a i With b i are the coordinates of the ith point in the xz plane respectively.

[0166] Fig.21 and Fig. 22The phases of the wavefront controller 50 at the entrance pupil of the sub-converging device array 401 when the second light beam deflection angle is (0°, 0°) and (40°, 15°) in Example 3 are shown respectively. Wherein, (0°, 0°) respectively indicates that the second light beam is deflected by 0° in the horizontal direction perpendicular to the optical axis and by 0° in the vertical direction perpendicular to the optical axis; (40°, 15°) respectively indicates that the second light beam is deflected by 0° in the horizontal direction perpendicular to the optical axis and by 0° in the vertical direction perpendicular to the optical axis.

[0167] In summary, the laser radar transmitting system provided in the embodiment of the present application forms an object-side telecentric system through the first super lens array and the aperture array, and realizes the deflection of the second light beam by virtue of the relative displacement of the light-emitting array and the first super lens array in the direction perpendicular to the optical axis. The system omits the MEMS reflective galvanometer, has a streamlined structure, and a simple optical path, which is conducive to the miniaturization and lightweight of the laser radar transmitting system.

[0168] The above is only a specific implementation of the embodiment of the present application, but the protection scope of the embodiment of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or replacements within the technical scope disclosed in the embodiment of the present application, which should be included in the protection scope of the embodiment of the present application. Therefore, the protection scope of the embodiment of the present application shall be based on the protection scope of the claims.

Claims

1. A laser radar transmitting system, characterized in that: The system comprises: A first superlens array (10) comprises at least one first superlens (101) arranged in an array, wherein the first superlens (101) is a Huygens superlens; A light-emitting array (20) comprising at least one light-emitting unit (201) arranged in an array; the light-emitting array (20) is arranged on the object focal plane of the first super lens array (10); the light-emitting unit (201) is used to generate a first light beam; the first light beam is a divergent laser whose main light beam is parallel to the optical axis of the first super lens array (10); An aperture array (30) comprising at least one sub-aperture (301) arranged in an array; the aperture array (30) is arranged on a side of the first super lens array (10) away from the light emitting array (20); the first light beam is converted into a second light beam through the first super lens array (10) and emitted from the aperture array (30); the second light beam is parallel light; The relative positions of the light emitting array (20) and the first super lens array (10) in a direction perpendicular to the optical axis are adjustable, so that the second light beam can be deflected to achieve scanning.

2. The system according to claim 1, characterized in that The system also satisfies: Δθ=arctan(Δd / L); Wherein, Δd is the relative displacement between the first super lens array (10) and the light emitting array (20) in a direction perpendicular to the optical axis; L is the distance between the aperture array (30) and the first super lens array (10); and Δθ is the rotation angle of the second light beam after the first super lens array (10) and the light emitting array (20) generate a relative displacement in a direction perpendicular to the optical axis.

3. The system according to claim 1, characterized in that The light emitting unit (201) comprises a point light source and a focus of converging laser light; The convergent laser forms the first light beam after passing through the focus.

4. The system according to claim 3, characterized in that The system further comprises a converging device array (40); the converging device array (40) comprises at least one sub-converging device (401) arranged in an array; the converging device array (40) is arranged upstream of the first super lens array (10) and is used to converge the incident laser light to at least one of the focal points; The sub-converging device (401) comprises a spherical refractive lens, an aspherical refractive lens or a second super lens.

5. The system according to claim 1, characterized in that The system further comprises a micro-electromechanical system; the micro-electromechanical system is configured to adjust the displacement of the light-emitting array and / or the first metalens array (10) along a direction perpendicular to the optical axis.

6. The system according to claim 5, characterized in that The driving stroke of the micro-electromechanical system is less than or equal to 10 mm.

7. The system according to claim 5, characterized in that The driving accuracy of the micro-electromechanical system is greater than or equal to 1 micron and less than or equal to 5 microns.

8. The system according to claim 5, characterized in that The operating frequency of the micro-electromechanical system is greater than 1 kHz.

9. The system according to claim 4, characterized in that The system further comprises a wavefront controller (50); the wavefront controller (50) is arranged at an entrance pupil of the converging device array (40); The wavefront controller (50) is used to adjust the focal position of the focusing device array (40).

10. The system according to claim 9, characterized in that The wavefront controller (50) comprises an array-arranged spatial light modulator, a digital micro-mirror array or an adjustable metasurface spatial light modulator.

11. The system according to claim 1 or 4, characterized in that: The first superlens (101) and the second superlens both include a substrate and a nanostructure layer disposed on the substrate; The nanostructure layer includes nanostructures arranged in an array.

12. The system according to claim 11, characterized in that The nanostructure layer includes superstructure units arranged in an array; The superstructure unit is a densely packed figure; the nanostructure is arranged at the center position and / or the vertex position of the densely packed figure.

13. The system according to claim 11, characterized in that The metalens also includes a filling material; The filling material is filled between the nanostructures.

14. The system of claim 13, wherein: An absolute value of a difference between a refractive index of the filling material and a refractive index of the nanostructure is greater than or equal to 0.

5.

15. The system of claim 12, wherein: The period of the superstructure unit is greater than or equal to 0.3λ c , and less than or equal to 2λ c ; Among them, λ c is the central wavelength of the operating band of the system.

16. The system of claim 11, wherein: The height of the nanostructure is greater than or equal to 0.3λ c , and less than or equal to 5λ c ; Among them, λ c is the central wavelength of the operating band of the system.

17. The system of claim 11, wherein: The shape of the nanostructure includes a polarization sensitive structure.

18. The system of claim 11, wherein: The shape of the nanostructure includes a polarization insensitive structure.

19. The system of claim 11, wherein: The metalens also includes an anti-reflection film; The antireflection film is arranged on a side of the substrate and the nanostructure layer adjacent to the air.

20. The system of claim 11, wherein: The phase of the first metalens (101) satisfies at least any one of the following formulas: Wherein, r is the distance from the center of the first superlens (101) to the center of any of the nanostructures; λ is the operating wavelength, is any phase related to the working wavelength, x, y are the mirror coordinates of the first superlens, and f is the focal length of the first superlens.

21. A wafer-level packaged device, characterized in that: Applicable to the laser radar transmitting system according to any one of claims 1 to 20, wherein the wafer-level packaged device comprises: an array of light sources disposed on a focal plane of the array of focusing devices (40); and A first spacing layer is arranged between the converging device array (40) and the light source array, and the height of the first spacing layer is equal to the focal length of the converging device array (40); The first super lens array (10) is arranged on a side of the converging device array (40) away from the light source array; and the object-side focal plane of the first super lens array (10) coincides with the focal plane of the converging device array (40); A second spacing side, arranged on a side of the first super lens array (10) away from the focusing device array (40), and used for supporting the aperture array (30); Furthermore, the light-emitting array (20) and / or the first super lens array (10) are arranged on a displacement platform to achieve relative displacement of the light-emitting array (20) and the first super lens array (10).

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