CN116859497A - Retroreflective assembly, retroreflector and communication device - Google Patents
Retroreflective assembly, retroreflector and communication device Download PDFInfo
- Publication number
- CN116859497A CN116859497A CN202210314775.0A CN202210314775A CN116859497A CN 116859497 A CN116859497 A CN 116859497A CN 202210314775 A CN202210314775 A CN 202210314775A CN 116859497 A CN116859497 A CN 116859497A
- Authority
- CN
- China
- Prior art keywords
- convex lens
- signal
- retroreflective
- incident
- assembly
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000004891 communication Methods 0.000 title claims abstract description 15
- 230000003287 optical effect Effects 0.000 claims abstract description 63
- 239000000758 substrate Substances 0.000 claims description 25
- 230000000712 assembly Effects 0.000 claims description 10
- 238000000429 assembly Methods 0.000 claims description 10
- 125000006850 spacer group Chemical group 0.000 claims description 9
- 238000003491 array Methods 0.000 claims description 2
- 230000008054 signal transmission Effects 0.000 claims 1
- 230000009286 beneficial effect Effects 0.000 abstract description 4
- 238000010586 diagram Methods 0.000 description 19
- 230000000694 effects Effects 0.000 description 11
- 239000000463 material Substances 0.000 description 8
- 238000007600 charging Methods 0.000 description 4
- 230000010354 integration Effects 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 239000003989 dielectric material Substances 0.000 description 2
- 239000000945 filler Substances 0.000 description 2
- 239000007769 metal material Substances 0.000 description 2
- 238000002834 transmittance Methods 0.000 description 2
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000005499 meniscus Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 238000003032 molecular docking Methods 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/12—Reflex reflectors
- G02B5/126—Reflex reflectors including curved refracting surface
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Communication System (AREA)
- Optical Elements Other Than Lenses (AREA)
Abstract
The application provides a retroreflective assembly, a retroreflector and a communication device. The retroreflection assembly comprises a reflecting mirror, a convex lens and a super surface arranged between the reflecting mirror and the convex lens; the reflector is provided with a bottom surface and a reflecting surface, the convex lens is arranged on one side of the reflecting surface of the reflector, and the distance between the reflecting surface of the reflector and the convex lens is smaller than the focal length of the convex lens; the super surface is used for modulating the phase of the incident signal so that the incident signals with mutually parallel incident paths can be converged at the same point on the reflecting surface. The retro-reflector can reduce the size of the retro-reflector in the optical axis direction, and is beneficial to realizing the light and thin design of devices.
Description
Technical Field
The present application relates to the field of communications technologies, and in particular, to a retroreflecting assembly, a retroreflecting device, and a communication device.
Background
A retro-reflector is an optical or electromagnetic device that reflects incident light or electromagnetic waves back and has a reflection path that is parallel to the incident path and in the opposite direction. The backfire device has wide application in wireless charging, communication, detection and other aspects.
In the prior art, the defects of larger thickness or low efficiency of the retroreflector are limited by the size requirement of the module, which is unfavorable for the development and the practicability of the retroreflector.
Disclosure of Invention
The application provides a retroreflection assembly, a retroreflector and communication equipment, which are used for reducing the thickness of a device and realizing the light and thin design of the device.
In a first aspect, the present application provides a retroreflective assembly that can be used in applications requiring signal feedback for communication, charging, detection, etc. The retroreflection assembly comprises a reflector, convex lenses and a super surface arranged between the convex lenses of the reflector. The reflector is provided with a bottom surface and a reflecting surface, and the convex lens is arranged on one side of the reflecting surface of the reflector. When the lens is applied, the bottom surface of the reflecting mirror faces the signal receiving end, and the convex lens faces the signal transmitting end. The incident signal can reach the reflecting surface of the reflector through the convex lens and the super surface to be reflected, and becomes a reflected signal. The super surface between the convex lens and the reflecting mirror can modulate the phase of the incident signal, so that the incident signal can be focused on the reflecting surface to meet the requirement of back reflection. Specifically, the distance between the reflecting surface of the reflecting mirror and the convex lens is smaller than the focal length of the convex lens, and the super surface is used for modulating the phase of the incident signal, so that the incident signals with parallel incident paths can be converged at the same point on the reflecting surface (i.e. the incident signals parallel to each other are focused at one point). According to the principle of reversibility of the light path, the reflected signal and the incident signal are mutually parallel, so that the reversibility of the signals is realized.
According to the retroreflector, the incident signals are refracted and converged through the convex lens, the super surface between the convex lens and the reflecting mirror can change the characteristic parameters such as amplitude, phase and polarization state of the incident signals to control, the incident signals are guided to and focused on the reflecting surface, the distance of the incident signals reaching the reflecting surface is shortened, and the distance between the reflecting mirror and the convex lens can be reduced to be smaller than the focal length of the convex lens. The retro-reflector can reduce the size of the retro-reflector in the optical axis direction, and is beneficial to realizing the light and thin design of devices.
Wherein the supersurface comprises a substrate and a phase modulating structure.The phase modulation structure is disposed on the substrate, and the specific position is not limited, i.e., the phase modulation structure is disposed on a side of the substrate facing the convex lens or a side of the substrate facing the reflecting mirror. In order to realize the back reflection of the signal, the refraction angle of the incident signal passing through the convex lens optical center in the substrate is set to be theta 2 ，-3°≤θ 2 Less than or equal to 3 degrees. The angle range can optimize the super surface and reduce the maximum emergent angle deviation.
Ideally continuously between the individual modulation phases. The phase gradient of the phase modulation structure in a direction perpendicular to the optical axis of the retroreflective assembly satisfies the following rule:
wherein ,is the phase gradient of the phase modulation structure, n 1 Refractive index of the structure on the light incident side of the super surface; n2 is the refractive index of the substrate, θ 1 An angle of incidence for an incident signal to the phase modulation structure. When the structure of the light incident side of the super surface is a convex lens, n 1 Specifically, the refractive index of the convex lens. Wherein θ 2 At 0 °, the retroreflective assembly is capable of making the incident signal and the outgoing signal symmetrical about the secondary (or primary) optical axis.
In some possible implementations, a transparent spacer dielectric layer is also provided between the supersurface and the convex lens. In this structure, n 1 Specifically the refractive index of the spacer dielectric layer. The spacer dielectric layer may provide support between the convex lens and the supersurface such that the face of the convex lens facing the supersurface and the face of the supersurface facing the convex lens can remain relatively parallel.
In order to facilitate the realization of a super-surface structure, the phase modulation structure may specifically comprise a plurality of sub-wavelength units. Along the direction perpendicular to the optical axis of the retroreflective assembly, the distance between any two points on the contour line of the cross section of each sub-wavelength unit is smaller than the wavelength of the incident signal, and the distance between any two adjacent sub-wavelength units is smaller than the wavelength of the incident signal.
In some possible implementations, the retroreflective assembly is required to achieve transmission of the signal. At this time, the reflection region and the transmission region may be provided on the mirror. The reflective area is used for reflecting signals, and the transmissive area is used for transmitting signals. In particular, the transmissive region may be realized in the form of a through-hole from which the incident signal may pass through to the receiving end. The transmissive region may also be implemented as a weak portion having a thickness less than that of the reflective region, and the incident signal may be transmitted through the weak portion.
In a second aspect, an embodiment of the present application further provides a retroreflector, which specifically includes a plurality of retroreflecting assemblies provided in the foregoing technical solutions. The multiple retroreflecting assembly arrays are arranged, so that a retroreflector with a larger area can be formed, and the retroreflecting effect with a larger area can be met.
In some possible implementations, there is a gap between the multiple retroreflective assemblies that can be used for signal passing. For example, a retroreflector formed by an array of circular retroreflective elements will form a plurality of gaps that can be used for direct signal passage. Thus, such a retro-reflector can be applied directly to a scene where a transmitted signal is desired.
In a third aspect, an embodiment of the present application further provides a communication device, including a transmitting module, a receiving module, and any one of the foregoing retroreflective assemblies. The transmitting module is used for transmitting signals, and the receiving module is used for receiving signals. The retroreflection assembly is arranged on one side of the receiving module, which faces the transmitting module, and the reflecting mirror of the retroreflection assembly faces the receiving module, so that signals transmitted by the transmitting module can be reflected back to the transmitting module.
Drawings
FIG. 1 is a schematic structural diagram of a retroreflective assembly according to an embodiment of the present application;
FIG. 2 is a schematic diagram of a reflector in a retroreflective assembly according to an embodiment of the present application;
FIG. 3 is a schematic diagram illustrating the working principle of a convex lens in a retroreflective assembly according to an embodiment of the present application;
FIG. 4 is a schematic diagram illustrating the operation of a retroreflective assembly according to an embodiment of the present application;
FIG. 5 is a schematic diagram of a reflection principle of a retroreflective element on an incident signal according to an embodiment of the present application;
FIG. 6 is a schematic diagram of a super-surface structure of a retroreflective assembly according to an embodiment of the present application;
FIG. 7 is a schematic diagram illustrating a reflection principle of a retroreflective element on an incident signal according to an embodiment of the present application;
fig. 8a to 8c are schematic diagrams illustrating reflection principles of a retroreflective element on an incident signal according to an embodiment of the present application;
FIG. 9 is a schematic diagram of a structure of a super surface in a retroreflective assembly according to an embodiment of the present application;
FIG. 10 is a schematic diagram of a structure of a sub-wavelength unit in a retroreflective assembly according to an embodiment of the present application;
FIG. 11 is a schematic diagram showing a variation of the cross section of the sub-wavelength unit in FIG. 10;
FIG. 12 is a schematic diagram of a structure of a sub-wavelength unit in a retroreflective assembly according to an embodiment of the present application;
FIG. 13 is a schematic diagram of a variation in cross-section of the sub-wavelength unit of FIG. 12;
FIG. 14 is a schematic view of a super surface structure of a retroreflective assembly according to an embodiment of the present application;
FIG. 15 is a schematic view of a structure of a super surface in a retroreflective assembly according to an embodiment of the present application;
FIG. 16a is a schematic view of a convex lens in a retroreflective assembly according to an embodiment of the present application;
FIG. 16b is a schematic diagram of a retroreflective assembly according to an embodiment of the present application;
FIG. 17a is a schematic diagram of a convex lens in a retroreflective assembly according to an embodiment of the present application;
FIG. 17b is a schematic diagram of a retroreflective assembly according to an embodiment of the present application;
FIG. 18 is a schematic view of a convex lens in a retroreflective assembly according to an embodiment of the present application;
FIG. 19 is a schematic view of a convex lens in a retroreflective assembly according to an embodiment of the present application;
FIG. 20 is a schematic view of a reflector in a retroreflective assembly according to an embodiment of the present application;
FIG. 21 is a schematic structural view of a retroreflective assembly according to an embodiment of the present application;
FIG. 22 is a schematic diagram of a retroreflector according to an embodiment of the present application;
FIG. 23 is a schematic diagram of a retroreflector according to an embodiment of the present application;
fig. 24 is a schematic structural diagram of a communication device according to an embodiment of the present application.
Reference numerals: 1-a mirror; 11-a reflective region; 12-a transmissive region; 2-convex lenses; 3-super surface; 31-a substrate; a 32-phase modulation structure; 321-sub-wavelength units; 4-filling; 5-spacer dielectric layer. A 10-retroreflective assembly; a 20-emission module; 30-a receiving module; 100-retro-reflector.
Detailed Description
The retro-reflector, which may also be referred to as a retro-reflector, may reflect incident signals (including light and electromagnetic waves) back, with the reflection direction parallel to the direction of incidence. The position or the angle state of the side of the reflected signal can be automatically acquired by the retro-reflector on the side of the transmitted signal. The existing retroreflectors have the defects of large size and low efficiency, and cannot meet the requirement of the development of the backfire.
Based on the above, the embodiment of the application provides a retroreflection assembly, a retroreflector comprising the retroreflection assembly and a communication device comprising the retroreflection assembly, which have smaller closed structures and are beneficial to the light and thin design of devices.
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be further described in detail with reference to the accompanying drawings.
The terminology used in the following examples is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the specification of the application and the appended claims, the singular forms "a," "an," "the," and "the" are intended to include, for example, "one or more" such forms of expression, unless the context clearly indicates to the contrary.
Reference in the specification to "one embodiment" or "some embodiments" or the like means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," and the like in the specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments" unless expressly specified otherwise. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless expressly specified otherwise.
The embodiment of the application provides a retroreflective assembly 10, and the retroreflective assembly 10 can be applied to a receiving terminal of a laser charging or wireless communication system, and is mainly used for reflecting an incident signal (light or electromagnetic wave) back. The reflected direction of the reflected signal is parallel and opposite to the direction of the incident signal. No additional alignment is required when the signal is transferred between the terminal transmitting the signal and the terminal receiving the signal.
As shown in fig. 1, the retroreflective assembly 10 includes a mirror 1, a convex lens 2, and a super surface 3 disposed between the mirror 1 and the convex lens 2. The retroreflective member 10 serves as an optical system whose optical axis P is parallel to the stacking direction of the reflecting mirror 1, the super surface 3, and the convex lens 2. In use, the convex lens 2 faces the emitting end of the signal to direct an incident signal from the emitting end into the retroreflective assembly 10. The reflector 1 is positioned at the receiving end of the signal, the incident signal reaches the reflector 1 after passing through the convex lens 2 and the super surface 3, and the reflector 1 reflects the incident signal and then the reflected signal is emitted out through the super surface 3 and the convex lens 2.
Specifically, as shown in fig. 2, the reflecting mirror 1 has a bottom surface a1 and a reflecting surface a2, and the convex lens 2 is provided on the reflecting surface a2 side of the reflecting surface 1. When the incident signal reaches the reflecting surface a2, the reflecting surface a2 has a strong reflecting effect on the incident signal, and a metal material can be selected. The angle between the incident signal and the normal line N perpendicular to the reflection surface a2 is the incident angle α1, and the angle between the reflected signal and the normal line N perpendicular to the reflection surface a2 is the reflection angle α2, α1=α2.
The convex lens 2 is composed of a material transparent to an incident signal, typically a dielectric material. The convex lens 2 needs to generate a certain aggregation effect on the incident signal, so that the super surface 3 is convenient for modulating the phase of the incident signal.
In general, as shown in fig. 3, the incident signals parallel to each other (the incident signals have the same incident angle) are converged to a convergence point after passing through the convex lens 2. The incident signals with different incident directions are converged to different convergence points after passing through the convex lens 2. The plane on which the convex lens 2 is located is set to be M1. The optical center of the convex lens 2 is O, and the optical center of the convex lens 2 is located on the optical axis P of the retroreflective member 10. The direction of the light passing through the optical center O of the convex lens 2 is unchanged. Taking the incident signals A0, A1 and A2 with different incident directions as examples, the incident direction of the incident signal A0 is perpendicular to the plane of the convex lens 2. The light of the incident signal A0 is converged to the converging point Q0, the light of the incident signal A1 is converged to the converging point Q1, and the light of the incident signal A2 is converged to the converging point Q2. The plane in which these convergence points lie may be defined as focal plane M0. An axis perpendicular to the plane M1 in which the convex lens 2 is located and passing through the optical center O is set as a main optical axis L0 (the main optical axis L0 coincides with the optical axis P of the retroreflective element 10), and an intersection point of the main optical axis L0 and the focal plane M0 is set as a main focus (i.e., a convergence point Q0). The other axis passing through the optical center O and not perpendicular to the plane in which the convex lens 2 is located is the secondary optical axis (secondary optical axis L1 of the incident signal A1, secondary optical axis L2 of the incident signal A2). The focal point of the secondary optical axis and the focal plane M0 is a secondary focal point, the secondary focal point of the secondary optical axis L1 is a convergence point Q1, and the secondary focal point of the secondary optical axis L2 is a convergence point Q2. The plane in which the convex lens 2 is located is the distance between M1 and the focal plane M0, i.e. the focal length f of the convex lens 2. In fig. 3, the signals are all double-headed arrows, and when any convergence point is used as a transmitting end to transmit signals to the convex lens 2, the paths of the signals are the same as the paths of the signals which can be converged at the convergence point by the convex lens 2.
The retroreflective assembly 10 provided in the embodiment of the present application, the mirror 1 is set as follows: the distance between the reflecting surface a2 of the reflecting mirror 1 and the convex lens 2 is smaller than the focal length f of the convex lens 2. For this purpose, a super surface 3 is provided between the reflecting mirror 1 and the convex lens 2 to converge the signal passing through the convex lens 2 to the reflecting surface a2 of the reflecting mirror 1. The principle is that an incident signal is incident on the super surface 3, and the super surface 3 can perform phase modulation on the incident signal, so that the phase of the incident signal is changed, and refraction is generated. This phenomenon in which the super surface 3 modulates the phase of a signal (light or electromagnetic wave) to produce refraction can be expressed by generalized snell's law.
As shown in fig. 4, the plane of the convex lens 2 is M1, the plane of the reflecting surface a2 of the reflecting mirror 1 is M2, and the plane of the super surface 3 is M3. Taking an example of an incident signal that is parallel to each other and is not perpendicular to the plane M1 of the convex lens 2, the incident signal passes through the convex lens 2 and can be focused to a convergence point Q (illustrated by a dotted line) on the focal plane M0. The distance between the focal plane M0 and the plane M1 of the convex lens 2 is the focal length f of the convex lens 2. The distance between the plane M2 of the reflector 1 and the plane M1 of the convex lens 2 is f ', f' being smaller than f. The super surface 3 may change the phase of the incident signal passing through the convex lens 2 so that the incident signal can be converged at a convergence point Q' (solid line example) on the plane M2 where the mirror 1 is located.
As shown in fig. 5, the reflection principle of the retroreflective element 10 provided in the embodiment of the present application will be described by taking an incident signal not perpendicular to the plane M1 of the convex lens 2 as an example. The incident signal is refracted by the convex lens 2, and the refracted incident signal is phase-changed by the super surface 3 and then is incident on the convergence point Q' (solid line example) on the plane M1 where the reflection surface a2 is located. The reflection surface a2 reflects the incident signal to form a reflected signal reaching the super surface 3 again. The angle of incidence between the incident signal and the normal N is the same as the angle of reflection between the reflected signal and the normal N between the plane M3 in which the super surface 3 lies and the plane M2 in which the reflecting surface a2 lies. The super surface 3 carries out phase modulation on the reflected signal so that the reflected signal can be emitted after passing through the convex lens 2, and the emitting direction is parallel to the incident angle, so that the retroreflection of the signal is realized.
It can be seen that, in the retroreflective assembly 10 provided in the embodiment of the present application, the super surface 3 capable of modulating the phase of the incident signal is disposed between the reflecting mirror 1 and the convex lens 2, and the incident signal is modulated by the super surface 3 so that the incident signal can be converged on the reflecting surface a2 of the reflecting mirror 1. The distance between the mirror 1 and the convex lens 2 can be reduced to be smaller than the focal length f of the convex lens 2. The retroreflective assembly 10 can reduce the size of the retroreflective assembly 10 in the optical axis direction, which is beneficial to realizing the light and thin design of the device. It should be appreciated that the retroreflective assembly 10 provided in the embodiments of the present application has a relatively closed structure, and has a high structural integration level, and can avoid the problem that dust deposition affects the performance of the device.
Wherein the structure of the supersurface 3 may be as shown with reference to figure 6. The supersurface 3 comprises a substrate 31 and a phase modulating structure 32. The phase modulation structure 32 may be disposed on the side of the substrate 31 facing the convex lens 2, or may be disposed on the side of the substrate 31 facing the mirror 1, which is not limited herein. Wherein the phase modulation structure 32 can adjust the phase of the signal. Refraction occurs as the signal passes through the substrate 31.
To increase the field angle range, the subsurface 3 makes the following adjustments to the incident signal: the refraction angle of the incident signal passing through the optical center of the convex lens 2 in the substrate 31 is made almost 0. As shown in fig. 7, taking an incident signal passing through the optical center O of the convex lens 2 (the optical center O coincides with the optical axis P) as an example, the incident signal enters the substrate 31 and is refracted in the substrate 31 after being phase-modulated by the phase modulation structure 32 of the super surface 3. The angle of incidence of the incident signal with the normal N in the substrate 31 is the angle of incidence θ 1 . The angle between the incident signal and the normal N in the substrate 31 is the refraction angle theta 2 . The outgoing signal and the incoming signal are parallel to each other, and the outgoing point of the outgoing signal on the plane M1 of the convex lens 2 is close to the optical center O of the convex lens 2.
θ here 2 About 0 DEG, and the specific range may be set to-3 DEG theta or less 2 Less than or equal to 3 degrees. As shown in fig. 8a, after the incident signal passing through the optical center O of the convex lens 2 is phase-adjusted by the phase modulation structure 32 of the super surface 3, the incident signal is phase-adjusted byIs refracted in the substrate 31 and then in a direction perpendicular to the mirror 1 (i.e. θ 2 =0°) reaches the reflecting surface a2. The incident signal is reflected by the reflecting surface a2 of the reflecting mirror 1 and returns to the super surface 3, and can return in the original path. I.e. the incident signal is co-routed with the reflected signal, which signal effects the back reflection of the original path.
As shown in fig. 8B, taking a group of mutually parallel incident signals as an example, an incident signal passing through the optical center O of the convex lens 2 is defined as a center signal B0, and an incident signal located on the left side of the center signal B0 is defined as a first signal B1. The center signal B0 is the signal on the rightmost side of the horizontal direction of the set of signals, and the first signal B1 is the signal on the leftmost side of the horizontal direction of the set of signals. Along the horizontal direction, there may be other paths of signals parallel to each other between the first signal B1 and the center signal B0. The center signal B0 passes through the optical center of the convex lens 2 and perpendicularly enters the reflecting surface a2 (the path from the plane M3 of the super surface 3 to the plane M2 of the reflecting mirror 1 coincides with the normal N) with respect to the reflecting surface a2. It should be appreciated that the retro-reflective optical path of the center signal B0 is similar to that of fig. 8a and will not be described again. The first signal B1 is refracted by the convex lens 2, the phase is adjusted by the phase modulation structure 32, and the converging point Q' reaching the reflecting surface a2 after being refracted by the substrate 31 is converged with the central signal B0. The first signal B1 is reflected by the reflection surface a2 and then emitted to the right of the normal line N, and passes through the super surface 3 and the convex lens 2 again and then emitted. According to the principle of reversibility of the light path, the emergent first signal B1 and the incident first signal B1 are parallel to each other. The distance from the incident point O' of the first signal B1 to the convex lens 2 to the optical center O of the convex lens 2 is d, and the distance from the exit point o″ of the first signal B1 from the convex lens 2 to the optical center O of the convex lens 2 is also d. The signal incidence range of the other paths between the first signal B1 and the center signal B0 is between the incidence point O' and the optical center O, and the signal emergence range of the other paths between the first signal B1 and the center signal B0 is between the emergence point o″ and the optical center O. That is, as long as the range of the first signal B1 with respect to the center signal B0 can be set, the retroreflection range of the group of signals can be limited, preventing the problem of unavailability due to the outgoing signal exceeding the range of the convex lens 2.
As shown in fig. 8c, taking a group of mutually parallel incident signals as an example, an incident signal passing through the optical center O of the convex lens 2 is defined as a center signal B0, an incident signal located on the left side of the center signal B0 is a first signal B1, and an incident signal located on the right side of the center signal B0 is a second signal B2. The first signal B1 is the leftmost signal in the horizontal direction of the set of signals, and the second signal B2 is the rightmost signal in the horizontal direction of the set of signals. Along the horizontal direction, there may be other multiple paths of signals parallel to each other between the first signal B1 and the central signal B0, and there may be other multiple paths of signals parallel to each other between the second signal B2 and the central signal B0. The center signal B0 passes through the optical center of the convex lens 2 and perpendicularly enters the reflecting surface a2 relative to the reflecting surface a2. The first signal B1 is incident from the incident point O' and exits from the exit point o″. The incidence point of the second signal B2 on the convex lens 2 coincides with the emission point o″ of the first signal B1 from the convex lens 2. According to the principle of reversible optical paths, the incident point O' of the first signal B1 on the convex lens 2, that is, the emergent point of the second signal B2 from the convex lens 2, and the emergent point o″ of the first signal B1 from the convex lens 2, that is, the incident point of the second signal B2 on the convex lens 2. If the first signal B1 and the second signal B2 are defined as signals of which the group of signals illustrates the horizontally outermost edges, the incidence range of the group of signals coincides with the reflection range.
As can be seen from the above embodiments, the retroreflective assembly 10 according to the present embodiment of the application can limit the range of the reflected signal by setting the position of the incident signal relative to the optical center of the convex lens 2 so that the incident signal and the reflected signal are symmetrical about the secondary optical axis (or the primary optical axis), thereby avoiding the problem that the emergent signal exceeds the range of the convex lens 2 and is not usable, and increasing the viewing angle of the retroreflective assembly 10.
In the embodiment of the present application, the phase modulation structure 32 has a continuously variable modulation phase, so that the phase modulation structure 32 can perform different phase modulations on different signals in a whole area, thereby achieving the above technical effects. It will be appreciated that in an ideal situation, the modulation phase variation of the phase modulation structure 32 is continuous. Specifically, as shown in fig. 7 and 8 a-8 c, along the plane of the super surface 3 (i.e., the plane perpendicular to the optical axis of the retroreflective assembly 10), the phase modulation structure 32 is composed of a plurality of points, one for each point of the phase modulation structure 32. The phase gradient of the phase modulation structure 32 satisfies the following law according to the generalized snell's law:
wherein ,n is the phase gradient of the phase modulation structure 32 1 A refractive index of a structure located on the light incident side of the super surface 3 (here, a refractive index of the convex lens 2); n is n 2 For the refractive index of the substrate 31, θ 1 Is the angle of incidence at which the incoming signal is incident on the phase modulation structure 32.
In practical applications, the phase value of the modulation phase corresponding to a certain position on the phase modulation structure 32 may be calculated. Specifically, a reference phase value of a reference position may be set, and a phase value of a target position adjacent to the reference position may be calculated according to the following formula:
wherein alpha is a reference phase value of the reference position, beta is a phase value of the target position, and L is a distance between the reference position and the target position. In the calculation, the phase value of one target position can be calculated according to the formula, and then the phase value of the next target position is calculated by taking the phase value of the target position as a reference phase value. And so on, the phase value at any location on the phase modulation structure 32 may ultimately be determined.
Specifically, as shown in fig. 9, the phase modulation structure 32 specifically includes a plurality of sub-wavelength units 321, where the plurality of sub-wavelength units 321 form an array structure, and each sub-wavelength unit 321 may correspond to a distance between adjacent sub-wavelength units 321 without limitation. In a direction perpendicular to the optical axis of the retroreflective assembly 10, the distance between any two points on the cross section of each sub-wavelength unit 321 is smaller than the wavelength of the incident signal. And, the interval between any two adjacent sub-wavelength units 321 is smaller than the wavelength of the incident signal, so that the sub-wavelength units 321 can perform phase modulation on the incident signal.
It should be appreciated that the phase change produced by the sub-wavelength unit 321 is related to the material, shape, size, etc. of the sub-wavelength unit 321. In designing, for a unit of a specific material, it is generally possible to test the phase change value in a certain shape or size and then adjust the shape or size. And then testing the corresponding phase change value, finally obtaining the corresponding shape or size in the phase range of 0-2 pi, and selecting according to the required phase change value. The material of the sub-wavelength unit 321 may be a transparent metal or dielectric material, such as titanium dioxide or silicon nitride.
Wherein the sub-wavelength units 321 of different materials correspond to different phase values, and the shapes or the sizes of the sub-wavelength units may be different, and the sub-wavelength units can be determined by testing or electromagnetic calculation. As one sub-wavelength unit 321 illustrated in fig. 10, has a height (direction parallel to the optical axis of the retroreflective assembly 10) of 500nm and a cross section (direction perpendicular to the optical axis of the retroreflective assembly 10) of square shape. When the side lengths of the cross section of the sub-wavelength unit 321 are respectively 100nm (shown as b1 in fig. 11), 200nm (shown as b2 in fig. 11), and 300nm (shown as b3 in fig. 11), the phase change values corresponding to the sub-wavelength unit 321 are 0.3, 0.6, and 0.9 compared with the reference phase. As one sub-wavelength unit 321 illustrated in fig. 12, has a height (direction parallel to the optical axis of the retroreflective assembly 10) of 600nm and a cross section (direction perpendicular to the optical axis of the retroreflective assembly 10) of a "C" shape. When the notch of "C" has an angle of 0 ° (C1 in fig. 13), 45 ° (C2 in fig. 13), and 60 ° (C3 in fig. 13) with respect to the horizontal direction, the phase change values corresponding to the sub-wavelength units 321 are 0.2, 0.3, and 0.4, respectively, compared to the reference phase.
Based on the top view of the super surface 3 illustrated in fig. 14, as shown in fig. 11 and 13, each of the sub-wavelength units 321 has the same shape and size, and has an elliptical cross section. Different sub-wavelength units 321 can be implemented to correspond to different phase values by rotating each sub-wavelength unit 321 by different angles around the axial direction of each sub-wavelength unit 321 (the direction perpendicular to the substrate 31, i.e., the direction of the optical axis of the retroreflective assembly 10). Or as shown in fig. 15 for a top view of the upper surface 3, each of the sub-wavelength units 321 has the same shape and the same height, and has a square cross section. By changing the side length of the sub-wavelength units 321 at different positions, different phase values corresponding to different sub-wavelength units 321 can be realized.
That is, after determining the phase change values corresponding to the sub-wavelength units 321 at the respective positions of the super-surface 3 in combination with the reference phase values, the sub-wavelength units 321 may be implemented according to the phase change values. That is, after the material is determined, it may be implemented in a specific size or shape so that the phase modulation structure 32 composed of the plurality of sub-wavelength units 321 can satisfy the phase modulation effect on the incident signal.
The structure of the convex lens 2 can be referred to in the following embodiments.
A lenticular lens as illustrated in fig. 16 a. Both surfaces of the convex lens 2 are convex in the direction of the optical axis W of the convex lens 2. When such a convex lens 2 is integrated into the retroreflective assembly 10, as shown in fig. 16b, the convex lens 2 is curved on the side facing the super surface 3, and the filler 4 can be provided in the gap between the convex lens 2 and the super surface 3 to keep the structure stable. The focusing effect of such a convex lens 2 is best, but the integration and thickness of the convex lens 2 are limited by the convexity.
A plano-convex lens as illustrated in fig. 17 a. Along the direction of the optical axis W of the convex lens 2, one surface of the convex lens 2 is convex, and the other surface is planar. In use, as shown in FIG. 1, a planar docking surface 3 may be provided. At this time, the signal is incident through the convex surface, and the performance surface is better in the aspect of the angle of view. Alternatively, as shown in fig. 17b, the convex surface may be abutted against the super surface 3 (in this case, the filler 4 may be provided between the convex lens 2 and the super surface 3 to keep the structure stable). At this time, the signal is first incident through the plane. With the retroreflective member 10, both surfaces in the optical axis direction are planar, and have high integration.
A fresnel biconvex lens as illustrated in fig. 18. Along the direction of the optical axis W of the convex lens 2, one surface of the convex lens 2 is a plane, and the other surface is inscribed with concentric circles from small to large. The arrangement can be referred to as convex lens 2 as shown in fig. 17 a. The Fresnel convex lens is equivalent to a convex lens of infrared rays and visible light in some cases, has a good light focusing effect and is low in cost.
A meniscus lens as illustrated in fig. 19. Along the direction of the optical axis W of the convex lens 2, one surface of the convex lens 2 is concave, the other surface is convex, and the curvature of the convex surface is larger than that of the concave surface. The arrangement can be referred to as convex lens 2 as shown in fig. 17 a.
It will be appreciated that in application, the convex lens 2 may be selected as desired, provided that the above focusing effect is achieved. Referring to fig. 1, 16a, 17a, 18 and 19, when the convex lens 2 is applied to the retroreflective assembly 10 provided in the embodiment of the present application, the optical axis W of the convex lens 2 coincides with the optical axis P of the retroreflective assembly 10.
For the mirror 1, in some application scenarios such as communication and charging, the mirror 1 needs to transmit a certain incident signal to be captured by the receiving end, which requires that the mirror 1 has a certain transmittance. If the transmittance of the material of the mirror 1 itself is low, as shown in fig. 20, the reflective region 11 and the transmissive region 12 may be provided on the mirror 1. The reflective area 11 is used for reflecting signals and the transmissive area 12 is used for transmitting signals. Specifically, the transmissive region 12 may be a through hole, which may allow a signal to pass directly therethrough. The through holes can be realized in a punching mode. Alternatively, the transmissive area 12 is a weak portion having a thickness smaller than that of the reflective area 11, so that a signal can be transmitted. The weak portion may be formed by grinding and thinning.
A retroreflective assembly 10 as shown in fig. 21 includes a mirror 1, a convex lens 2, a spacer dielectric layer 5, and a supersurface 3 stacked in this order in the optical axis direction. The spacer dielectric layer 5 is a material transparent to signals (light or electromagnetic waves). The spacer medium layer 5 may provide support between the convex lens 2 and the super surface 3 such that the face of the convex lens 2 facing the super surface 3 and the face of the super surface 3 facing the convex lens 2 can be kept relatively parallel.
In the retroreflective assembly 10 shown in fig. 21, the phase gradient of the phase modulation structure 32 in the supersurface 3 is also satisfiedWherein n is 1 Is the refractive index of the structure on the light-entering side of the supersurface 3. In the retroreflective element 10, the spacer medium layer 5 is located on the light-entering side of the supersurface 3, and therefore n is here 1 Is the refractive index of the spacer dielectric layer 5.
Based on the retroreflective assembly 10 described above, embodiments of the present application also provide a retroreflective 100 that can be used to achieve large area retroreflective. Generally, if the retroreflector 100 is the structure shown in fig. 1, the phase gradient difference between different points at a position far from the center of the retroreflector 100 is small, and in order to achieve the retroreflection effect, a higher requirement is placed on the preparation accuracy of the phase modulation structure 32 in the super-surface 3. To avoid the above-mentioned problems, the retroreflector 100 in the embodiment of the present application is specifically composed of a plurality of the above-mentioned retroreflective assemblies 10, and the plurality of retroreflective assemblies 10 may be combined into the retroreflector 100 with a larger area in an array manner.
Taking one type of retroreflective article 100 as shown in fig. 22 for example, the retroreflective article 100 includes a plurality of equally sized hexagonal retroreflective elements 10. Any adjacent retroreflective assemblies 10 are joined without gaps therebetween. Based on this concept, the retroreflective assembly 10 can also be triangular, rectangular, diamond-shaped, etc. structures, all of which can achieve a gapless retroreflective 100.
In other embodiments, a retro-reflector 100 is shown in FIG. 23. The retroreflective article 100 includes a plurality of equally sized circular retroreflective assemblies 10. A gap M may be formed between the plurality of retroreflective assemblies 10. The gap M may act as an aperture for the passage of a signal when some of the retroreflector 100 is required to have a signal-transmitting function. It should be appreciated that other retroreflective assemblies 10 that do not achieve a gapless array can achieve this effect.
In addition, as shown in fig. 24, the embodiment of the present application further provides a communication device, which specifically includes the above-mentioned transmitting module 20, the above-mentioned receiving module 30, and the above-mentioned retroreflective assembly 10. The transmitting module 20 is configured to transmit a signal (light or electromagnetic wave), and the receiving module 30 is configured to receive the signal sent by the transmitting module 20. The retroreflective assembly 10 is disposed on a side of the receiving module 30 facing the transmitting module 20, and is configured to reflect a signal emitted by the transmitting module 20, so as to implement retroreflection of the signal. Wherein the reflecting surface a2 of the reflecting mirror 1 of the retroreflective assembly 10 faces the receiving module 30 and the convex lens 2 faces the emitting module 20.
Possibly, the retroreflective assembly 10 is used as a stand-alone device as shown in fig. 1. Alternatively, the retroreflective assembly 10 may be used with the retroreflective 100 shown in fig. 21 or 22 spliced together. And selecting according to different requirements.
The foregoing is merely illustrative embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think about variations or substitutions within the technical scope of the present application, and the application should be covered. Therefore, the protection scope of the application is subject to the protection scope of the claims.
Claims (11)
1. A retroreflective assembly comprising a mirror, a convex lens, and a supersurface disposed between the mirror and the convex lens;
the reflector is provided with a bottom surface and a reflecting surface, the convex lens is arranged on one side of the reflecting surface of the reflector, and the distance between the reflecting surface of the reflector and the convex lens is smaller than the focal length of the convex lens;
the super surface is used for modulating the phase of an incident signal so that the incident signals with mutually parallel incident paths can be converged at the same point on the reflecting surface.
2. The retroreflective assembly of claim 1 wherein the supersurface comprises a substrate and a phase modulating structure disposed on a side of the substrate facing the convex lens or a side of the substrate facing the mirror;
an angle of refraction of an incident signal passing through the convex lens optical center within the substrate is θ 2 ，-3°≤θ 2 ≤3°。
3. The retroreflective assembly of claim 2 wherein the phase gradient of the phase modulating structure in a direction perpendicular to the optical axis of the retroreflective assembly satisfies the following rule:
wherein ,n is the phase gradient of the phase modulation structure 1 Refractive index of the structure on the light incident side of the super surface; n is n 2 For the refractive index of the substrate, θ 1 An angle of incidence for the incident signal to the phase modulation structure.
4. A retroreflective assembly according to claim 2 or 3, wherein the θ 2 Is 0 deg..
5. The retroreflective assembly of any of claims 2-4, wherein the phase modulation structure includes a plurality of sub-wavelength units; the distance between any two points on the cross section of each sub-wavelength unit along the direction perpendicular to the optical axis of the retroreflection assembly is smaller than the wavelength of the incident signal; and the distance between any two adjacent sub-wavelength units is smaller than the wavelength of the incident signal.
6. The assembly of any one of claims 1-5, further comprising a transparent spacer medium layer disposed between the convex lens and the supersurface.
7. The assembly of any one of claims 1-6, wherein the mirror has a reflective region and a transmissive region, the transmissive region being for signal transmission.
8. The retroreflective assembly of claim 7 wherein the transmissive region is a through-hole or a weakened portion having a thickness less than a thickness of the reflective region.
9. A retroreflective article comprising a plurality of retroreflective elements according to any one of claims 1-8, a plurality of said retroreflective element arrays being disposed.
10. The retroreflector of claim 9 wherein there is a gap between a plurality of the retroreflective assemblies, the gap being for the signal to pass through.
11. A communication device comprising a transmitting module, a receiving module, and the retroreflective assembly of any one of claims 1-8;
the retroreflection assembly is arranged on one side of the receiving module, which faces the transmitting module, and the reflecting surface of the reflecting mirror of the retroreflection assembly faces the receiving module.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210314775.0A CN116859497A (en) | 2022-03-28 | 2022-03-28 | Retroreflective assembly, retroreflector and communication device |
| PCT/CN2023/083197 WO2023185600A1 (en) | 2022-03-28 | 2023-03-22 | Retroreflection assembly, retroreflector, and communication device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210314775.0A CN116859497A (en) | 2022-03-28 | 2022-03-28 | Retroreflective assembly, retroreflector and communication device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116859497A true CN116859497A (en) | 2023-10-10 |
Family
ID=88199263
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210314775.0A Pending CN116859497A (en) | 2022-03-28 | 2022-03-28 | Retroreflective assembly, retroreflector and communication device |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN116859497A (en) |
| WO (1) | WO2023185600A1 (en) |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DK111293D0 (en) * | 1993-10-04 | 1993-10-04 | Franke Kell Erik | RETROREFLECTIVE FOLI MATERIAL |
| JPH10221681A (en) * | 1997-02-04 | 1998-08-21 | Sony Corp | Reflection type single plate type picture display element and projection type picture display device using the same |
| US6507441B1 (en) * | 2000-10-16 | 2003-01-14 | Optid, Optical Identification Technologies Ltd. | Directed reflectors and systems utilizing same |
| JP5820955B1 (en) * | 2014-06-27 | 2015-11-24 | 株式会社アスカネット | Retroreflector and stereoscopic image display device using the same |
| CN207424282U (en) * | 2017-10-21 | 2018-05-29 | 西安方元明科技股份有限公司 | A kind of retroreflection device |
| CN111981438A (en) * | 2020-09-09 | 2020-11-24 | 北京环境特性研究所 | Super-surface lens corner reflector |
-
2022
- 2022-03-28 CN CN202210314775.0A patent/CN116859497A/en active Pending
-
2023
- 2023-03-22 WO PCT/CN2023/083197 patent/WO2023185600A1/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| WO2023185600A1 (en) | 2023-10-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP7085559B2 (en) | Optical system | |
| US7701648B2 (en) | Fresnel lens | |
| US10684470B2 (en) | Array-based floating display | |
| US8134778B2 (en) | Monolithic eccentric Mersenne-Cassegrain telescope | |
| KR20180123504A (en) | From the incident electromagnetic waves, a device that forms at least one focused beam in a close- | |
| US6433942B1 (en) | Optical apparatus | |
| EP1660919B1 (en) | Retroreflective device comprising gradient index lenses | |
| US3858046A (en) | Catadioptric beamsplitter system | |
| CN109581330B (en) | Integrated optical phased array chip | |
| CN114545370A (en) | Laser radar transmitting system and corresponding receiving system thereof | |
| TW202109090A (en) | Prism and optical imaging system | |
| CN214478427U (en) | Semiconductor laser | |
| CN116859497A (en) | Retroreflective assembly, retroreflector and communication device | |
| CN111884029A (en) | Polarization beam combiner and laser | |
| US20230221462A1 (en) | Metasurface optical device with tilted nano-structure units and optical apparatus | |
| US10281655B2 (en) | Field inversion waveguide using micro-prism array | |
| CN103887707B (en) | A kind of semiconductor laser with high-power high light beam quality laser | |
| CN209746121U (en) | integrated optical phased array chip | |
| EP1316835A2 (en) | A micro-opto-electro-mechanical system (MOEMS) comprising reflective Fresnel zone plates | |
| CN113031293A (en) | Wavelength selection system | |
| CN218824795U (en) | Coupling device | |
| JP2012008230A (en) | Optical lens barrel and optical device | |
| US20230367129A1 (en) | Diffractive optical element and terminal device | |
| RU2434255C1 (en) | Retroreflective element | |
| WO2023188947A1 (en) | Optical lens, optical system, and imaging device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |