Superlens for dot matrix projection and dot matrix projection device comprising same

Abstract

The utility model provides a superlens for dot matrix projection and a dot matrix projection device comprising the same. The super lens is configured to provide a replication diffraction phase, and the replication diffraction phase is used for performing replication projection on emitted light of the light source array to obtain a target dot matrix; the target dot matrix comprises a plurality of unit dot matrixes arranged in an array; in the frequency domain, the pattern of each unit dot matrix is consistent with the pattern of the light source array, and the unit dot matrixes are periodically arranged in the target direction in the frequency domain; the super lens comprises a plurality of unit cells which are periodically arranged; the periodic arrangement direction of the unit cells is perpendicular to the target direction. The dot matrix projected by the super lens provided by the utility model can greatly reduce background noise, and theoretically does not generate any background noise, so that the contrast ratio and the signal-to-noise ratio of the dot matrix are greatly improved, and the application range of the dot matrix is widened.

Description

Technical Field

[0001] The present disclosure relates to the technical field of optical systems, and in particular to a metalens for dot matrix projection and a dot matrix projection device including the metalens. Background Art

[0002] In the design scheme of generating dot matrix based on super lens, the super lens provided by the prior art usually carries a certain intensity of background noise when projecting the dot matrix. At the same time, the process deviation in actual processing will further enhance the background noise. The contrast and signal-to-noise ratio of the dot matrix with large background noise are both low, which leads to a small application range. Utility Model Content

[0003] In order to solve the above technical problems, the present application provides a metalens for dot matrix projection and a dot matrix projection device containing the same. The dot matrix projected by the metalens provided by the present application can greatly reduce the background noise, and theoretically can not generate any background noise, thereby greatly improving the contrast and signal-to-noise ratio of the dot matrix, and increasing the application range of the dot matrix.

[0004] A first aspect of an embodiment of the present application provides a metalens for dot matrix projection, wherein the metalens is configured to provide a replica diffraction phase, and the replica diffraction phase is used to replicate and project the emitted light of a light source array to obtain a target dot matrix;

[0005] The target dot matrix includes a plurality of unit dot matrices arranged in an array; in the frequency domain, the pattern of each of the unit dot matrices is consistent with the pattern of the light source array, and the unit dot matrices are periodically arranged along the target direction in the frequency domain;

[0006] The superlens includes a plurality of periodically arranged unit cells, wherein the unit cell is the smallest structural unit of the superlens for realizing dot matrix projection, and the unit cell includes at least one micro-nano structural unit; and the periodic arrangement direction of the unit cell is perpendicular to the target direction.

[0007] Optionally, the target direction only includes a first direction in the frequency domain; and the unit cells are periodically arranged at least in a direction perpendicular to the first direction.

[0008] Optionally, the target direction includes a first direction and a second direction in the frequency domain, and the first direction and the second direction are not parallel to each other;

[0009] The periodic arrangement direction of the unit cells includes a third direction and a fourth direction; wherein the third direction is perpendicular to the first direction, and the fourth direction is perpendicular to the second direction.

[0010] Optionally, the metalens satisfies:

[0011]

[0012] Among them, D u' is the arrangement period of the unit cells in the fourth direction, and the projection distance obtained by projecting in the first direction; Δu' is the arrangement period of the unit lattice in the first direction; D v' is the projection distance obtained by projecting the arrangement period of the unit cells in the third direction in the second direction; Δv' is the arrangement period of the unit lattice in the second direction.

[0013] Optionally, the micro-nano structure units are periodically arranged along the third direction and the fourth direction respectively; and the superlens satisfies:

[0014]

[0015] Among them, p u' is the projection distance obtained by projecting the arrangement period of the micro-nano structure units in the fourth direction in the first direction; p v' is the arrangement period of the micro-nano structure units in the third direction, and the projection distance obtained by projecting in the second direction; m is a positive integer; n is a positive integer; λ is the central wavelength of the emitted light.

[0016] Optionally, the metalens is further configured to provide a collimation phase, which collimates the emitted light of the light source array based on the effective focal length of the metalens.

[0017] Optionally, the metalens satisfies:

[0018]

[0019] Wherein, FL is the effective focal length of the metalens; L1 is the first side length of the light source array; L2 is the second side length of the light source array, and the direction of the second side length is parallel to the second direction; Δu' is the arrangement period of the unit lattice in the first direction; Δv' is the arrangement period of the unit lattice in the second direction; θ u is the angle between the first direction and the direction of the first side length; θ v is the angle between the second direction and the direction of the second side length; λ is the central wavelength of the emitted light.

[0020] A second aspect of the present application provides a dot matrix projection device, which includes: a light source array; and a super lens as provided in the above embodiment.

[0021] Optionally, the dot matrix projection device includes a collimating element for providing a collimating phase; the collimating phase collimates the emitted light of the light source array based on the effective focal length of the collimating element.

[0022] Optionally, the effective focal length of the collimating element satisfies:

[0023]

[0024] Wherein, FL is the effective focal length of the collimating element; L1 is the first side length of the light source array; L2 is the second side length of the light source array, and the direction of the second side length is parallel to the second direction; Δu' is the arrangement period of the unit lattice in the first direction; Δv' is the arrangement period of the unit lattice in the second direction; θ u is the angle between the first direction and the direction of the first side length; θ v is the angle between the second direction and the direction of the second side length; λ is the central wavelength of the emitted light.

[0025] Optionally, the collimating element is the superlens.

[0026] Optionally, the collimating element is a collimating lens group; the collimating lens group is arranged between the superlens and the light source array; the collimating lens group includes at least one lens.

[0027] In the embodiment of the present application, the arrangement direction of the unit cell of the metalens is perpendicular to the target direction in the frequency domain, that is, perpendicular to the periodic arrangement direction of the unit lattice in the frequency domain. By configuring the arrangement direction of the unit cell to be perpendicular to the periodic arrangement direction of the unit lattice in the frequency domain, the target lattice projected by the metalens has almost no background noise, or even theoretically no background noise at all, thereby improving the contrast and signal-to-noise ratio of the lattice, thereby increasing the application range of the lattice. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the background technology, the drawings required for use in the embodiments of the present application or the background technology are described below. Obviously, the drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 A schematic diagram showing the function of a metalens in one embodiment of the present application when applied to a dot matrix projection device.

[0030] Figure 2 A diagram of an array of light sources in one embodiment is shown.

[0031] Figure 3 The metalens pair in one embodiment is shown Figure 2 The target dot matrix obtained by replicating and projecting the emitted light from the light source array of the shown pattern.

[0032] Figure 4 Shows Figure 3 The diagram shows the position distribution of the target dot matrix in the frequency domain.

[0033] Figure 5 Shows Figure 4 A partial enlarged view of the target dot array in the frequency domain is shown.

[0034] Figure 6 In one embodiment, Figure 4 The unit cell of the target lattice arrangement in the frequency domain is shown.

[0035] Figure 7 In another embodiment, Figure 4 The unit cell of the target lattice arrangement in the frequency domain is shown.

[0036] Figure 8 A schematic diagram showing the regular distribution of micro-nano structural units in a unit cell in one embodiment is shown.

[0037] Fig. 9 (a) shows the pattern of the target dot matrix in the spatial domain projected by the dot matrix projection device provided in Example 1 of the present application.

[0038] Fig. 9 (b) shows the pattern of the target dot matrix in the frequency domain projected by the dot matrix projection device provided in Example 1 of the present application.

[0039] Fig. 9 (c) shows the arrangement of the unit cells of the superlens in Example 1 of the present application.

[0040] Fig. 9 (d) shows the pattern of the light source array in Example 1 of the present application.

[0041] Fig.10 (a) shows the pattern of the target dot matrix in the spatial domain projected by the dot matrix projection device provided in Example 2 of the present application.

[0042] Fig.10 (b) shows the pattern of the target dot matrix in the frequency domain projected by the dot matrix projection device provided in Example 2 of the present application.

[0043] Fig.10 (c) shows the arrangement of the unit cells of the superlens in Example 2 of the present application.

[0044] Fig.10 (d) shows the pattern of the light source array in Example 2 of the present application.

[0045] Fig.11 (a) shows the pattern of the target dot matrix in the spatial domain projected by the dot matrix projection device provided in Example 3 of the present application.

[0046] Fig.11 (b) shows the pattern of the target dot matrix in the frequency domain projected by the dot matrix projection device provided in Example 3 of the present application.

[0047] Fig.11 (c) shows the arrangement of the unit cells of the superlens in Example 3 of the present application.

[0048] Fig.11 (d) shows the pattern of the light source array in Example 3 of the present application.

[0049] Fig.12 (a) shows the pattern of the target dot matrix in the spatial domain projected by the dot matrix projection device provided in Example 4 of the present application.

[0050] Fig.12 (b) shows Fig.12 (a) A partial enlarged view.

[0051] Fig.12 (c) shows the pattern of the target dot matrix in the frequency domain projected by the dot matrix projection device provided in Example 4 of the present application.

[0052] Fig.12 (d) shows the arrangement of the unit cells of the superlens in Example 4 of the present application.

[0053] Fig.12 (e) shows the pattern of the light source array in Example 4 of the present application.

[0054] Fig.13 (a) shows the pattern of the target dot matrix in the spatial domain projected by the dot matrix projection device provided in Example 5 of the present application.

[0055] Fig.13 (b) shows the pattern of the target dot matrix in the frequency domain projected by the dot matrix projection device provided in Example 5 of the present application.

[0056] Fig.13 (c) shows the arrangement of the unit cells of the superlens in Example 5 of the present application.

[0057] Fig.13 (d) shows the pattern of the light source array in Example 5 of the present application.

[0058] Fig.14 (a) shows the pattern of the target dot matrix in the spatial domain projected by the dot matrix projection device provided in Example 6 of the present application.

[0059] Fig.14 (b) shows the pattern of the target dot matrix in the frequency domain projected by the dot matrix projection device provided in Example 6 of the present application.

[0060] Fig.14 (c) shows the arrangement of the unit cells of the superlens in Example 6 of the present application.

[0061] Fig.14 (d) shows the pattern of the light source array in Example 6 of the present application.

[0062] Fig.15 (a) shows the pattern of the target dot matrix in the spatial domain projected by the dot matrix projection device provided in Example 7 of the present application.

[0063] Fig.15 (b) shows the pattern of the target dot matrix in the frequency domain projected by the dot matrix projection device provided in Example 7 of the present application.

[0064] Fig.15 (c) shows the arrangement of the unit cells of the superlens in Example 7 of the present application.

[0065] Fig.15 (d) shows the pattern of the light source array in Example 7 of the present application.

[0066] Fig.16 (a) shows the pattern of the target dot matrix in the spatial domain projected by the dot matrix projection device provided in Example 8 of the present application.

[0067] Fig.16 (b) shows the pattern of the target dot matrix in the frequency domain projected by the dot matrix projection device provided in Example 8 of the present application.

[0068] Fig.16 (c) shows the arrangement of the unit cells of the superlens in Example 8 of the present application.

[0069] Fig.16 (d) shows the pattern of the light source array in Example 8 of the present application.

[0070] Fig.17 (a) shows the pattern of the target dot matrix in the spatial domain projected by the dot matrix projection device provided in Example 9 of the present application.

[0071] Fig.17 (b) shows the pattern of the target dot matrix in the frequency domain projected by the dot matrix projection device provided in Example 9 of the present application.

[0072] Fig.17 (c) shows the arrangement of the unit cells of the superlens in Example 9 of the present application.

[0073] Fig.17 (d) shows the pattern of the light source array in Example 9 of the present application.

[0074] Fig.18 (a) shows the pattern of the target dot matrix in the spatial domain projected by the dot matrix projection device provided in Example 10 of the present application.

[0075] Fig.18 (b) shows the pattern of the target dot matrix in the frequency domain projected by the dot matrix projection device provided in Example 10 of the present application.

[0076] Fig.18 (c) shows the arrangement of the unit cells of the superlens in Example 10 of the present application.

[0077] Fig.18 (d) shows the pattern of the light source array in Example 10 of the present application.

[0078] Fig.19 (a) shows the pattern of the target dot matrix in the spatial domain projected by the dot matrix projection device provided in Example 11 of the present application.

[0079] Fig.19 (b) shows the pattern of the target dot matrix in the frequency domain projected by the dot matrix projection device provided in Example 11 of the present application.

[0080] Fig.19 (c) shows the arrangement of the unit cells of the superlens in Example 11 of the present application.

[0081] Fig.19 (d) shows the pattern of the light source array in Example 11 of the present application.

[0082] Fig. 20 (a) shows the pattern of the target dot matrix in the spatial domain projected by the dot matrix projection device provided in Example 12 of the present application.

[0083] Fig. 20 (b) shows the pattern of the target dot matrix in the frequency domain projected by the dot matrix projection device provided in Example 12 of the present application.

[0084] Fig. 20 (c) shows the arrangement of the unit cells of the superlens in Example 12 of the present application.

[0085] Fig. 20 (d) shows the pattern of the light source array in Example 12 of the present application.

[0086] Fig.21 (a) shows the pattern of the target dot matrix in the spatial domain projected by the dot matrix projection device provided in Example 13 of the present application.

[0087] Fig.21 (b) shows the pattern of the target dot matrix in the frequency domain projected by the dot matrix projection device provided in Example 13 of the present application.

[0088] Fig.21 (c) shows the arrangement of the unit cells of the superlens in Example 13 of the present application.

[0089] Fig.21 (d) shows the pattern of the light source array in Example 13 of the present application.

[0090] Fig. 22 (a) shows the pattern of the target dot matrix in the spatial domain projected by the dot matrix projection device provided in Example 14 of the present application.

[0091] Fig. 22 (b) shows the pattern of the target dot matrix in the frequency domain projected by the dot matrix projection device provided in Example 14 of the present application.

[0092] Fig. 22 (c) shows the arrangement of the unit cells of the superlens in Example 14 of the present application.

[0093] Fig. 22 (d) shows the pattern of the light source array in Example 14 of the present application.

[0094] Fig.23 (a) shows the pattern of the target dot matrix in the spatial domain projected by the dot matrix projection device provided in Example 15 of the present application.

[0095] Fig.23 (b) shows the pattern of the target dot matrix in the frequency domain projected by the dot matrix projection device provided in Example 15 of the present application.

[0096] Fig.23 (c) shows the arrangement of the unit cells of the superlens in Example 15 of the present application.

[0097] Fig.23 (d) shows the pattern of the light source array in Example 15 of the present application.

[0098] List of reference numerals: 10 - light source array, 101 - light source, 11 - light source substrate, 20 - super lens, 30 - collimating lens group. DETAILED DESCRIPTION

[0099] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these example embodiments are provided so that the description of the present application will be more comprehensive and complete and the concepts of the example embodiments will be fully conveyed to those skilled in the art. The accompanying drawings are only schematic illustrations of the present application and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted.

[0100] In addition, the described features, structures or characteristics may be combined in one or more example embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the example embodiments of the present application. However, those skilled in the art will appreciate that the technical solution of the present application may be practiced while omitting one or more of the specific details, or other methods, components, steps, etc. may be adopted. In other cases, known structures, methods, implementations or operations are not shown or described in detail to avoid obscuring the present application and making the various aspects of the present application obscure.

[0101] Some of the blocks shown in the accompanying drawings are functional entities that do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0102] In the related art, there is a dot matrix projection scheme: the metalens replicates and projects the emitted light of the light source array by providing a replicated diffraction phase, thereby obtaining a target dot matrix formed by replication and splicing. Regardless of the replication and splicing method used to obtain the target dot matrix, the arrangement of the minimum structural unit of the metalens used to achieve dot matrix projection is always fixed in advance, that is, the arrangement of the unit cells of the metalens is always fixed in advance. For example: regardless of the replication and splicing method used to obtain the target dot matrix, the unit cells of the metalens are always arranged in a square lattice, a hexagonal lattice or a ring lattice.

[0103] It can be seen that the arrangement of the unit cells of the super lens in the related art is essentially irrelevant to the specific replication and splicing method used by the target dot matrix. The inventor of the present application found that it is for this reason that the dot matrix projected by the related art always carries a certain intensity of background noise, resulting in a low contrast and signal-to-noise ratio of the dot matrix, which in turn leads to a small application range.

[0104] In order to overcome the above-mentioned defects, the present application proposes a metalens for dot matrix projection and a dot matrix projection device including the metalens.

[0105] Figure 1 FIG. 1 is a schematic diagram showing the function of a metalens in an embodiment of the present application when applied to a dot matrix projection device. Figure 1 The dot matrix projection device includes a light source array 10 and a super lens 20. The light source array 10 includes a light source substrate 11 and light sources 101 arranged in an array on the light source substrate 11. The super lens 20 modulates the emitted light received from the light source array 10, thereby projecting a target dot matrix with a certain number of dots and patterns.

[0106] The metalens 20 provided in the present application is configured to provide a replica diffraction phase, which is used to replicate and project the emitted light of the light source array 10 to obtain a target dot matrix. The target dot matrix includes a plurality of unit dot matrices arranged in an array. In the frequency domain, the pattern of each unit dot matrix is ​​consistent with the pattern of the light source array; and the unit dot matrix is ​​periodically arranged along the target direction in the frequency domain.

[0107] Figure 2 FIG. 1 shows a diagram of a light source array 10 in one embodiment, Figure 3 The metalens 20 in one embodiment is shown Figure 2 The target dot matrix is ​​obtained by replicating and projecting the emitted light of the light source array 10 of the pattern shown. Figure 2 and Figure 3 As shown, the replica diffraction phase provided by the super lens 20 can replicate the emitted light of the light source array 10 and can be Figure 2 The dot matrix of the light source array shown is copied into multiple copies and spliced ​​to project in the spatial domain. Figure 3 It should be noted that, due to the nonlinear coordinate transformation from the frequency domain to the spatial domain, most of the unit lattices will be distorted in the spatial domain, but this does not deny that the pattern of the unit lattice in the frequency domain is consistent with the pattern of the light source array, nor does it deny that the unit lattice is periodically arranged along the target direction in the frequency domain.

[0108] The super lens 20 includes a plurality of unit cells arranged in an array. Specifically, the unit cell is the minimum structural unit of the super lens 20 for realizing dot matrix projection, and each unit cell includes at least one micro-nano structural unit. In general, each unit cell includes a plurality of micro-nano structural units. The plurality of micro-nano structural units in the same unit cell can be distributed regularly or randomly, as long as the unit cell can be supported as the minimum structural unit for dot matrix projection.

[0109] In the embodiment of the present application, the arrangement direction of the unit cells of the metalens 20 is perpendicular to the target direction in the frequency domain, that is, perpendicular to the periodic arrangement direction of the unit lattice in the frequency domain. By configuring the arrangement direction of the unit cells to be perpendicular to the periodic arrangement direction of the unit lattice in the frequency domain, the target lattice projected by the metalens 20 has almost no background noise, or even theoretically no background noise at all, thereby improving the contrast and signal-to-noise ratio of the lattice, thereby increasing the application range of the lattice.

[0110] In one embodiment, the target direction only includes the first direction in the frequency domain. That is, in this embodiment, the unit lattice is periodically arranged only along the first direction in the frequency domain. Therefore, in this embodiment, the unit cells in the super lens 20 only need to be periodically arranged in a direction perpendicular to the first direction to completely eliminate the background noise in theory.

[0111] It should be noted that, in this embodiment, the unit cells may be periodically arranged only in the direction perpendicular to the first direction, or may be periodically arranged in the direction perpendicular to the first direction and in other directions at the same time.

[0112] In one embodiment, the target direction includes a first direction and a second direction in the frequency domain, and the first direction and the second direction are not parallel to each other. That is, in this embodiment, the unit lattice is periodically arranged along the first direction in the frequency domain, and is also periodically arranged along the second direction in the frequency domain. The first direction and the second direction can be perpendicular to each other, or can be inclined to each other.

[0113] In this embodiment, the unit cells in the super lens 20 are adaptively arranged periodically along the third direction and the fourth direction, respectively; wherein the third direction is perpendicular to the first direction, and the fourth direction is perpendicular to the second direction.

[0114] Figure 4 Shows Figure 3 The diagram shows the position distribution of the target dot matrix in the frequency domain. Figure 5 It shows Figure 4 A partial enlarged view of the target dot array in the frequency domain is shown. Figure 6 In one embodiment, Figure 4 The unit cell of the target lattice arrangement in the frequency domain is shown. Figure 7 In another embodiment, Figure 4 The unit cell of the target lattice arrangement in the frequency domain is shown.

[0115] The coordinate system of the two-dimensional plane where the point matrix in the spatial domain is located is composed of the x-axis and the y-axis, and the x-axis is perpendicular to the y-axis; the coordinate system of the two-dimensional plane where the point matrix in the frequency domain is located is composed of the u-axis and the v-axis, and the u-axis is perpendicular to the v-axis. Figure 3 to Figure 4In the spatial domain, the unit lattices are closely arranged along the y-axis to form rows of lattices, and there is a certain offset between adjacent rows of lattices; in the frequency domain, the unit lattices are closely arranged along the v-axis to form rows of lattices, and there is also a certain offset between adjacent rows of lattices.

[0116] See also Figures 3 to 5 In fact, in the frequency domain, the unit lattices corresponding to adjacent diffraction orders are arranged along the u' direction and the v' direction respectively; therefore, the u' direction can be recorded as the first direction in which the unit lattices are periodically arranged in the frequency domain, and the v' direction can be recorded as the second direction in which the unit lattices are periodically arranged in the frequency domain.

[0117] In order to eliminate the background noise of the target lattice in the spatial domain, the unit cells in the metalens are controlled to be arranged periodically along the third direction, that is, along the direction perpendicular to the u' direction; at the same time, the unit cells are controlled to be arranged periodically along the fourth direction, that is, along the direction perpendicular to the v' direction. For details, see Figure 6 as well as Figure 7 , the smallest parallelogram or the smallest rectangle enclosed by the solid line is a unit cell. Whether it is a parallelogram or a rectangle, the unit cells are periodically arranged in the vertical direction along the u' direction and in the vertical direction along the v' direction. Figure 4 As shown in the target lattice, if the unit cell in the super lens 20 is Figure 6 or Figure 7 If the projection is performed in the manner shown, the target dot matrix can theoretically completely eliminate background noise.

[0118] It should be noted that when the unit lattice is periodically arranged in the first direction and the second direction in the frequency domain, in order to eliminate background noise, in addition to controlling the periodic arrangement of the unit cells in the third direction and the fourth direction, it is also necessary to control the arrangement period of the unit cells in the third direction and the arrangement period in the fourth direction.

[0119] Specifically, in order to arrange the unit lattice periodically in the first direction in the frequency domain, it is necessary to control the unit cells to be arranged periodically in the third direction perpendicular to the first direction; in this case, if it is not considered that the unit lattice also needs to be arranged periodically in the second direction in the frequency domain, the arrangement period of the unit cells in the third direction can be set arbitrarily. However, in order to arrange the unit lattice periodically in the second direction, it is necessary to control the arrangement period of the unit cells in the third direction in combination with the second direction and the arrangement period of the unit lattice in the second direction.

[0120] Similarly, in order to arrange the unit lattice periodically in the second direction in the frequency domain, it is necessary to control the arrangement period of the unit cells in the fourth direction perpendicular to the second direction. In order to arrange the unit lattice periodically in the first direction in the frequency domain, it is necessary to control the arrangement period of the unit cells in the fourth direction in combination with the first direction and the arrangement period of the unit lattice in the first direction.

[0121] Specifically, the projection distance obtained by projecting the arrangement period of the unit cells in the third direction onto the second direction and the arrangement period of the unit lattice in the second direction should be reciprocals of each other. At the same time, the projection distance obtained by projecting the arrangement period of the unit cells in the fourth direction onto the first direction and the arrangement period of the unit lattice in the first direction should be reciprocals of each other.

[0122] See also Figures 5 to 7 , the arrangement period of the unit lattice in the first direction (i.e., u' direction) is Δu', and the arrangement period in the second direction (i.e., v' direction) is Δv'; at the same time, the arrangement period of the unit cell in the third direction (i.e., the direction perpendicular to the u' direction) is Δu', and the projection distance obtained by projecting in the second direction (i.e., v' direction) is D v' , the arrangement period of the unit cell in the fourth direction (ie, the direction perpendicular to the v' direction), and the projection distance obtained by projection in the first direction (ie, the u' direction) is D u' Δu' and D u' should be reciprocal of each other, and Δv' and D v' They should be reciprocal of each other.

[0123] Thus, in one embodiment, the metalens 20 satisfies:

[0124]

[0125] As mentioned above, when a unit cell contains multiple micro-nano structural units, these micro-nano structural units can be regularly distributed or randomly distributed. Figure 8 FIG. 1 is a schematic diagram showing the regular distribution of micro-nanostructure units in a unit cell in an embodiment. Figures 6 to 8 , the black solid circle represents the micro-nano structure unit. In one embodiment, the multiple micro-nano structures contained in the unit cell are regularly distributed, and these micro-nano structure units are also periodically arranged along the third direction (i.e., the direction perpendicular to u') and the fourth direction (i.e., the direction perpendicular to v'). Therefore, in this embodiment, the metalens also satisfies:

[0126]

[0127]

[0128] Among them, p u' is the projection distance obtained by projecting the arrangement period of the micro-nano structure units in the fourth direction in the first direction; p v' is the arrangement period of the micro-nano structural units in the third direction, and the projection distance obtained by projecting in the second direction; m is a positive integer; n is a positive integer; λ is the central wavelength of the emitted light.

[0129] It should be noted that the value of m needs to make p u' Less than λ; at the same time, the value of n needs to make p v' That is, the values ​​of m and n need to make the micro-nano structure unit meet the size requirements of the sub-wavelength structure.

[0130] It should be noted that the light emitted by the light source array 10 usually has a certain divergence angle. Therefore, in order to support the replication of the diffraction phase, the light emitted by the light source array 10 needs to be collimated.

[0131] Therefore, in one embodiment, the metalens 20 is also configured to provide a collimation phase. Specifically, the collimation phase is designed based on the effective focal length of the metalens 20 to collimate the emitted light of the light source array 10. In this case, the phase provided by the metalens 20 includes two parts: one part is the collimation phase, and the other part is the replica diffraction phase. These two parts of the phase can be integrated into the metalens 20 by superposition.

[0132] Optionally, the collimation phase of the superlens 20 satisfies:

[0133]

[0134] Wherein, FL is the effective focal length of the metalens 20, x m ,y m is the position coordinate of the micro-nano structure unit in the superlens 20 relative to the center of the superlens 20, N is the order, is a constant, a i is the phase coefficient.

[0135] In one embodiment, if Figure 2 As shown, the first side length of the light source array 10 is L1, and the second side length is L2; ​​and Figure 5 As shown, in the frequency domain, the unit lattice is periodically arranged along the first direction u' and periodically arranged along the second direction v', and the second direction v' is parallel to the direction of the second side length. Therefore, in this embodiment, the effective focal length of the super lens 20 satisfies:

[0136]

[0137] Wherein, FL is the effective focal length of the super lens 20; L1 is the first side length of the light source array 10; L2 is the second side length of the light source array 10, and the direction of the second side length is parallel to the second direction; Δu' is the arrangement period of the unit lattice in the first direction; Δv' is the arrangement period of the unit lattice in the second direction; θ u is the angle between the first direction and the direction of the first side length; θ v is the angle between the second direction and the direction of the second side length; λ is the central wavelength of the emitted light.

[0138] It should be noted that the effective focal length FL calculated by using this formula takes an absolute value to ensure that the effective focal length FL is a positive value.

[0139] The present application also provides a dot matrix projection device. Figure 1 The dot matrix projection device comprises: a light source array 10; and a super lens 20 provided in any of the above embodiments. The super lens 20 is arranged on the light output side of the light source array 10, so that the super lens 20 replicates and splices the received emitted light of the light source array 10 by providing a replicated diffraction phase, thereby projecting a target dot matrix.

[0140] Similarly to the description of the superlens 20 in the above embodiment, the target dot matrix projected by the dot matrix projection device provided in the present application has almost no background noise, or even theoretically no background noise at all, thereby improving the contrast and signal-to-noise ratio of the dot matrix, thereby increasing the application range of the dot matrix.

[0141] In one embodiment, the light sources 101 in the light source array 10 are arranged in a regular array.

[0142] In one embodiment, the light sources 101 in the light source array 10 are arranged in a pseudo-random array.

[0143] As mentioned above, the light emitted by the light source array 10 usually has a certain divergence angle, so in one embodiment, the dot matrix projection device includes a collimating element for providing a collimating phase. The collimating phase collimates the light emitted by the light source array 10 based on the effective focal length of the collimating element.

[0144] In one embodiment, if Figure 2 As shown, the first side length of the light source array 10 is L1, and the second side length is L2; ​​and Figure 5 As shown, in the frequency domain, the unit lattice is periodically arranged along the first direction u' and periodically arranged along the second direction v', and the second direction v' is parallel to the direction of the second side length. Therefore, in this embodiment, the effective focal length of the collimating element satisfies:

[0145]

[0146] Wherein, FL is the effective focal length of the collimating element; L1 is the first side length of the light source array 10; L2 is the second side length of the light source array 10, and the direction of the second side length is parallel to the second direction; Δu' is the arrangement period of the unit lattice in the first direction; Δv' is the arrangement period of the unit lattice in the second direction; θ u is the angle between the first direction and the direction of the first side length; θ v is the angle between the second direction and the direction of the second side length; λ is the central wavelength of the emitted light.

[0147] It should be noted that the effective focal length FL calculated by using this formula takes an absolute value to ensure that the effective focal length FL is a positive value.

[0148] In one embodiment, the collimating element in the dot projection device is a super lens 20 .

[0149] In one embodiment, if Figure 1 As shown, the collimating element in the dot matrix projection device is a collimating lens group 30. The collimating lens group 30 is arranged between the metalens and the light source array; thus, the emitted light of the light source array is first collimated by the collimating lens group 30, and then the metalens replicates and projects the collimated light beam to obtain the target dot matrix. The collimating lens group 30 can include only one lens or multiple lenses.

[0150] The present application also provides a method for designing a superlens 20, which is used to design the superlens 20 provided in any of the above embodiments. The method comprises:

[0151] Based on the design goal, the position distribution of the unit dot array contained in the target dot array in the frequency domain is obtained, the pattern of the unit dot array is consistent with the pattern of the light source array, and the unit dot array is periodically arranged along the target direction in the frequency domain;

[0152] Determine the position distribution of the unit cells of the super lens 20 based on the position distribution of the unit lattice in the frequency domain, wherein the unit cells are arranged periodically, and the periodic arrangement direction of the unit cells is perpendicular to the target direction;

[0153] Based on the position distribution of the unit cells and the position distribution of the unit lattice in the frequency domain, the replica diffraction phase provided by the superlens 20 is designed to obtain a superlens for replicating and projecting the emitted light of the light source array into a target lattice.

[0154] In one embodiment, based on the design goal, the target dot matrix in the frequency domain can be directly obtained, and then the target dot matrix in the frequency domain is periodically divided according to the pattern of the light source array to obtain the position distribution of the unit dot matrix in the frequency domain.

[0155] In one embodiment, based on the design goal, obtaining the position distribution of the unit lattices included in the target lattice in the frequency domain includes:

[0156] Based on the design goal, the position distribution of the target point array in the spatial domain is obtained;

[0157] The position distribution of the target point array in the spatial domain is mapped to the frequency domain to obtain the position distribution of the unit point array in the frequency domain.

[0158] In this embodiment, based on the design goal, the target dot matrix in the spatial domain can be directly obtained. In this case, based on the coordinate conversion relationship between the spatial domain and the frequency domain, the target dot matrix in the frequency domain can be obtained from the target dot matrix in the spatial domain. After obtaining the target dot matrix in the frequency domain, the target dot matrix in the frequency domain is periodically divided according to the pattern of the light source array, and the position distribution of the unit dot matrix in the frequency domain can be obtained.

[0159] Specifically, the spatial domain and the frequency domain satisfy the following coordinate transformation relationship:

[0160]

[0161] Among them, x and y are the two-dimensional coordinates of the plane where the target lattice is located in the spatial domain, z is the distance between the target lattice and the super lens, and u and v are the two-dimensional coordinates of the plane where the target lattice is located in the frequency domain.

[0162] In one embodiment, determining the position distribution of the unit cells based on the position distribution of the unit lattice in the frequency domain includes:

[0163] Determine the target direction based on the position distribution of the unit point array in the frequency domain;

[0164] Based on the target direction, the periodic arrangement direction of the unit cells is determined, and based on the periodic arrangement direction of the unit cells, the position distribution of the unit cells is determined.

[0165] In this embodiment, after determining the position distribution of the unit lattice in the frequency domain, the periodic arrangement direction of the unit lattice in the frequency domain can be determined, that is, the target direction can be determined. Then, it can be naturally determined that the direction perpendicular to the target direction is the periodic arrangement direction of the unit cell. Then, based on the periodic arrangement direction of the unit cell, the position distribution of the unit cell can be determined.

[0166] It should be noted that if the target direction is one-dimensional, that is, if the target direction only includes the first direction in the frequency domain, then in this embodiment, it is basically only necessary to control the position distribution of the unit cells to satisfy the periodic arrangement in the direction perpendicular to the target direction. If the target direction is two-dimensional, that is, if the target direction includes the first direction and the second direction in the frequency domain that are not parallel to each other, then in this embodiment, in addition to controlling the position distribution of the unit cells to satisfy the periodic arrangement in the direction perpendicular to the target direction, it is also necessary to control the projection distance of the arrangement period of the unit cells to satisfy the reciprocal relationship with the arrangement period of the unit lattice.

[0167] To further describe the features of the metalens 20 and the dot matrix projection device provided in the embodiments of the present application, the present application provides 15 embodiments as shown below:

[0168] Example 1

[0169] Embodiment 1 of the present application provides a dot matrix projection device. Fig. 9 (a) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the space domain, Fig. 9 (b) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the frequency domain, Fig. 9 (c) shows the arrangement of the unit cells of the super lens 20, Fig. 9 (d) shows a pattern of the light source array 10. In which, each unit cell is used to control the arrangement period m and n of the micro-nano structure units, which are 8 and 12 respectively.

[0170] Table 1. Parameters of the dot matrix projection device provided in Example 1

[0171] project Numeric Working wavelength 940nm FOV (inscribed rectangle) 63*58(deg*deg) VCSEL light source size 600*400(um*um) Total number of copies 39 <![CDATA[θ u *i v ]]> -12.5*0(deg*deg) <![CDATA[P u *P v ]]> 542.8*556.1(nm*nm) Effective focal length 2.8mm Dot Matrix Arrangement Random Dots

[0172] Example 2

[0173] Embodiment 2 of the present application provides a dot matrix projection device. Fig.10 (a) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the space domain, Fig.10 (b) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the frequency domain, Fig.10 (c) shows the arrangement of the unit cells of the super lens 20, Fig.10 (d) shows a pattern of the light source array 10. In which, each unit cell is used to control the arrangement period m and n of the micro-nano structure units, which are 8 and 12 respectively.

[0174] Table 2. Parameters of the dot matrix projection device provided in Example 2

[0175] project Numeric Working wavelength 940nm FOV (inscribed rectangle) 96*80(deg*deg) VCSEL light source size 600*400(um*um) Total number of copies 59 <![CDATA[θ u *i v ]]> -12.5*0(deg*deg) <![CDATA[P u *P v ]]> 535.3*548.4(nm*nm) Effective focal length 2.8mm Dot Matrix Arrangement Random Dots

[0176] Example 3

[0177] Embodiment 3 of the present application provides a dot matrix projection device. Fig.11 (a) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the space domain, Fig.11 (b) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the frequency domain, Fig.11 (c) shows the arrangement of the unit cells of the super lens 20, Fig.11 (d) shows a pattern of the light source array 10. In which, each unit cell is used to control the arrangement period m and n of the micro-nano structure units, which are 9 and 13 respectively.

[0178] Table 3. Parameters of the dot matrix projection device provided in Example 3

[0179] project Numeric Working wavelength 940nm FOV (inscribed rectangle) 120*93.8(deg*deg) VCSEL light source size 590*410(um*um) Total number of copies 85 <![CDATA[θ u *i v ]]> -13*0(deg*deg) <![CDATA[P u *P v ]]> 531.3*543.3(nm*nm) Effective focal length 3.08mm Dot Matrix Arrangement Random Dots

[0180] Example 4

[0181] Embodiment 4 of the present application provides a dot matrix projection device. Fig.12 (a) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the space domain, Fig.12 (b) shows Fig.12 (a) is a partial enlarged view. Fig.12 (c) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the frequency domain, Fig.12 (d) shows the arrangement of the unit cells of the super lens 20, Fig.12 (e) shows a pattern of the light source array 10. In which, each unit cell is used to control the arrangement period m and n of the micro-nano structure units, which are 13 and 19 respectively.

[0182] Table 4. Parameters of the dot matrix projection device provided in Example 4

[0183]

[0184]

[0185] Example 5

[0186] Embodiment 5 of the present application provides a dot matrix projection device. Fig.13 (a) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the space domain, Fig.13(b) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the frequency domain, Fig.13 (c) shows the arrangement of the unit cells of the super lens 20, Fig.13 (d) shows a pattern of the light source array 10. In which, each unit cell is used to control the arrangement period m and n of the micro-nano structure units, which are 8 and 10 respectively.

[0187] Table 5. Parameters of the dot matrix projection device provided in Example 5

[0188] project Numeric Working wavelength 940nm FOV (inscribed rectangle) 96*51.6(deg*deg) VCSEL light source size 550*450(um*um) Total number of copies 39 <![CDATA[θ u *i v ]]> -11.6*0(deg*deg) <![CDATA[P u *P v ]]> 537.3*536.2(nm*nm) Effective focal length 2.57mm Dot Matrix Arrangement Random Dots

[0189] Example 6

[0190] Embodiment 6 of the present application provides a dot matrix projection device. Fig.14 (a) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the space domain, Fig.14 (b) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the frequency domain, Fig.14 (c) shows the arrangement of the unit cells of the super lens 20, Fig.14 (d) shows a pattern of the light source array 10. In which, each unit cell is used to control the arrangement period m and n of the micro-nano structure units, which are 13 and 10 respectively.

[0191] Table 6. Parameters of the dot matrix projection device provided in Example 6

[0192] project Numeric Working wavelength 940nm FOV (inscribed rectangle) 71*61(deg*deg) VCSEL light source size 400*500(um*um) Total number of copies 35 <![CDATA[θ u *i v ]]> -32*0(deg*deg) <![CDATA[P u *P v ]]> 367.9*451.2(nm*nm) Effective focal length 2.4mm Dot Matrix Arrangement Random Dots

[0193] Example 7

[0194] Embodiment 7 of the present application provides a dot matrix projection device. Fig.15 (a) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the space domain, Fig.15 (b) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the frequency domain, Fig.15 (c) shows the arrangement of the unit cells of the super lens 20, Fig.15 (d) shows a pattern of the light source array 10. In which, each unit cell is used to control the arrangement period m and n of the micro-nano structure units, which are 17 and 10 respectively.

[0195] Table 7. Parameters of the dot matrix projection device provided in Example 7

[0196] project Numeric Working wavelength 940nm FOV (inscribed rectangle) 66*72(deg*deg) VCSEL light source size 450*760(um*um) Total number of copies 77 <![CDATA[θ u *i v ]]> 0*0(deg*deg) <![CDATA[P u *P v ]]> 552.9*556.6(nm*nm) Effective focal length 4.5mm Dot Matrix Arrangement Random Dots

[0197] Example 8

[0198] Embodiment 8 of the present application provides a dot matrix projection device. Fig.16 (a) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the space domain, Fig.16 (b) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the frequency domain, Fig.16 (c) shows the arrangement of the unit cells of the super lens 20, Fig.16 (d) shows a pattern of the light source array 10. In which, each unit cell is used to control the arrangement period m and n of the micro-nano structure units, which are 17 and 10 respectively.

[0199] Table 8. Parameters of the dot matrix projection device provided in Example 8

[0200] project Numeric Working wavelength 940nm FOV (inscribed rectangle) 66*72(deg*deg) VCSEL light source size 450*760(um*um) Total number of copies 77 <![CDATA[θ u *i v ]]> 0*0(deg*deg) <![CDATA[P u *P v ]]> 552.9*556.6(nm*nm) Effective focal length 4.5mm Dot Matrix Arrangement Array arrangement

[0201] Example 9

[0202] Embodiment 9 of the present application provides a dot matrix projection device. Fig.17 (a) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the space domain, Fig.17 (b) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the frequency domain, Fig.17 (c) shows the arrangement of the unit cells of the super lens 20, Fig.17 (d) shows a pattern of the light source array 10. In which, each unit cell is used to control the arrangement period m and n of the micro-nano structure units, which are 9 and 6 respectively.

[0203] Table 9. Parameters of the dot matrix projection device provided in Example 9

[0204] project Numeric Working wavelength 940nm FOV (inscribed rectangle) 79*56(deg*deg) VCSEL light source size 410*670(um*um) Total number of copies 16 <![CDATA[θ u *i v ]]> 17.9*0(deg*deg) <![CDATA[P u *P v ]]> 462.5*451.5(nm*nm) Effective focal length 1.93mm Dot Matrix Arrangement Array arrangement

[0205] Example 10

[0206] Embodiment 10 of the present application provides a dot matrix projection device. Fig.18 (a) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the space domain, Fig.18 (b) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the frequency domain, Fig.18 (c) shows the arrangement of the unit cells of the super lens 20, Fig.18 (d) shows a pattern of the light source array 10. In which, each unit cell is used to control the arrangement period m and n of the micro-nano structure units, which are 9 and 9 respectively.

[0207] Table 10. Parameters of the dot projection device provided in Example 10

[0208] project Numeric Working wavelength 940nm FOV (inscribed rectangle) 96*63(deg*deg) VCSEL light source size 400*400(um*um) Total number of copies 35 <![CDATA[θ u *i v ]]> 15*15(deg*deg) <![CDATA[P u *P v ]]> 487.5*487.5(nm*nm) Effective focal length 1.87mm Dot Matrix Arrangement Regular lattice

[0209] Embodiment 11

[0210] Embodiment 11 of the present application provides a dot matrix projection device. Fig.19 (a) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the space domain, Fig.19 (b) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the frequency domain, Fig.19 (c) shows the arrangement of the unit cells of the super lens 20, Fig.19 (d) shows a pattern of the light source array 10. In which, each unit cell is used to control the arrangement period m and n of the micro-nano structure units, which are 11 and 9 respectively.

[0211] Table 11. Parameters of the dot projection device provided in Example 11

[0212]

[0213]

[0214] Example 12

[0215] Embodiment 12 of the present application provides a dot matrix projection device. Fig. 20 (a) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the space domain, Fig. 20 (b) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the frequency domain, Fig. 20 (c) shows the arrangement of the unit cells of the super lens 20, Fig. 20 (d) shows a pattern of the light source array 10. In which, each unit cell is used to control the arrangement period m and n of the micro-nano structure units, which are 11 and 9 respectively.

[0216] Table 12. Parameters of the dot projection device provided in Example 12

[0217] project Numeric Working wavelength 850nm FOV (inscribed rectangle) 74*71(deg*deg) VCSEL light source size 400*500(um*um) Total number of copies 67 <![CDATA[θ u *i v ]]> 17.4*0(deg*deg) <![CDATA[P u *P v ]]> 549.1*562.5(nm*nm) Effective focal length 2.98mm Dot Matrix Arrangement Random Dots

[0218] Embodiment 13

[0219] Embodiment 13 of the present application provides a dot matrix projection device. Fig.21(a) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the space domain, Fig.21 (b) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the frequency domain, Fig.21 (c) shows the arrangement of the unit cells of the super lens 20, Fig.21 (d) shows a pattern of the light source array 10. In which, each unit cell is used to control the arrangement period m and n of the micro-nano structure units, which are 11 and 9 respectively.

[0220] Table 13. Parameters of the dot matrix projection device provided in Example 13

[0221]

[0222]

[0223] Embodiment 14

[0224] Embodiment 14 of the present application provides a dot matrix projection device. Fig. 22 (a) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the space domain, Fig. 22 (b) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the frequency domain, Fig. 22 (c) shows the arrangement of the unit cells of the super lens 20, Fig. 22 (d) shows a pattern of the light source array 10. In which, each unit cell is used to control the arrangement period m and n of the micro-nano structure units, which are 16 and 8 respectively.

[0225] Table 14. Parameters of the dot projection device provided in Example 14

[0226] project Numeric Working wavelength 905nm FOV (inscribed rectangle) 67*76(deg*deg) VCSEL light source size 350*700(um*um) Total number of copies 45 <![CDATA[θ u *i v ]]> -33.7*0(deg*deg) <![CDATA[P u *P v ]]> 376.5*452.5(nm*nm) Effective focal length 2.8mm Dot Matrix Arrangement Regular lattice

[0227] Embodiment 15

[0228] Embodiment 15 of the present application provides a dot matrix projection device. Fig.23 (a) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the space domain, Fig.23 (b) shows the pattern of the target dot matrix projected by the dot matrix projection device provided in this embodiment in the frequency domain, Fig.23 (c) shows the arrangement of the unit cells of the super lens 20, Fig.23 (d) shows a pattern of the light source array 10. In which, each unit cell is used to control the arrangement period m and n of the micro-nano structure units, which are 11 and 13 respectively.

[0229] Table 15. Parameters of the dot projection device provided in Example 15

[0230] project Numeric Working wavelength 905nm FOV (inscribed rectangle) 71*41(deg*deg) VCSEL light source size 700*600(um*um) Total number of copies 35 <![CDATA[θ u *i v ]]> 0*0(deg*deg) <![CDATA[P u *P v ]]> 493.6*487.3(nm*nm) Effective focal length 4.2mm Dot Matrix Arrangement Random Dots

[0231] It can be seen that the periodic arrangement of the unit cells in the superlens designed according to the above requirements can project a dot matrix without carrying background noise, thus meeting various application scenarios requiring high signal-to-noise ratio.

[0232] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the utility model disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the appended claims.

Claims

1. A metalens for dot projection, characterized in that: The metalens is configured to provide a replica diffraction phase, and the replica diffraction phase is used to replicate and project the emitted light of the light source array to obtain a target dot matrix; The target dot matrix includes a plurality of unit dot matrices arranged in an array; In the frequency domain, the pattern of each of the unit dot arrays is consistent with the pattern of the light source array, and the unit dot arrays are periodically arranged along the target direction in the frequency domain; The superlens includes a plurality of periodically arranged unit cells, wherein the unit cell is the smallest structural unit of the superlens for realizing dot matrix projection, and the unit cell includes at least one micro-nano structural unit; and the periodic arrangement direction of the unit cell is perpendicular to the target direction.

2. The metalens according to claim 1, characterized in that The target direction only includes a first direction in the frequency domain; the unit cells are periodically arranged at least in a direction perpendicular to the first direction.

3. The metalens according to claim 1, characterized in that The target direction includes a first direction and a second direction in the frequency domain, and the first direction and the second direction are not parallel to each other; The periodic arrangement direction of the unit cells includes a third direction and a fourth direction; wherein the third direction is perpendicular to the first direction, and the fourth direction is perpendicular to the second direction.

4. The metalens according to claim 3, characterized in that The metalens satisfies: Among them, D u' is the arrangement period of the unit cells in the fourth direction, and the projection distance obtained by projecting in the first direction; Δu' is the arrangement period of the unit lattice in the first direction; D v' is the projection distance obtained by projecting the arrangement period of the unit cells in the third direction in the second direction; Δv' is the arrangement period of the unit lattice in the second direction.

5. The superlens according to claim 4, characterized in that The micro-nano structure units are periodically arranged along the third direction and the fourth direction respectively; the super lens satisfies: Among them, p u' is the projection distance obtained by projecting the arrangement period of the micro-nano structure units in the fourth direction in the first direction; p v' is the arrangement period of the micro-nano structure units in the third direction, and the projection distance obtained by projecting in the second direction; m is a positive integer; n is a positive integer; λ is the central wavelength of the emitted light.

6. The superlens according to claim 3, characterized in that The metalens is further configured to provide a collimation phase that collimates the emitted light from the light source array based on an effective focal length of the metalens.

7. The superlens according to claim 6, characterized in that The metalens satisfies: Wherein, FL is the effective focal length of the metalens; L1 is the first side length of the light source array; L2 is the second side length of the light source array, and the direction of the second side length is parallel to the second direction; Δu' is the arrangement period of the unit lattice in the first direction; Δv' is the arrangement period of the unit lattice in the second direction; θ u is the angle between the first direction and the direction of the first side length; θ v is the angle between the second direction and the direction of the second side length; λ is the central wavelength of the emitted light.

8. A dot matrix projection device, characterized in that: The dot matrix projection device comprises: a light source array; and a super lens as described in any one of claims 3 to 5.

9. The dot projection device according to claim 8, characterized in that: The dot matrix projection device includes a collimating element for providing a collimating phase; the collimating phase is based on the effective focal length of the collimating element to collimate the emitted light of the light source array.

10. The dot projection device according to claim 9, characterized in that: The effective focal length of the collimating element satisfies: Wherein, FL is the effective focal length of the collimating element; L1 is the first side length of the light source array; L2 is the second side length of the light source array, and the direction of the second side length is parallel to the second direction; Δu' is the arrangement period of the unit lattice in the first direction; Δv' is the arrangement period of the unit lattice in the second direction; θ u is the angle between the first direction and the direction of the first side length; θ v is the angle between the second direction and the direction of the second side length; λ is the central wavelength of the emitted light.

11. The dot projection device according to claim 9, characterized in that: The collimating element is the superlens.

12. The dot projection device according to claim 9, characterized in that: The collimating element is a collimating lens group; the collimating lens group is arranged between the super lens and the light source array; the collimating lens group includes at least one lens.

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