Protection structure for protecting metasurface and alignment system
Patent Information
- Application Number
- CN202422311038.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-23
- Publication Date
- 2025-07-04
- Estimated Expiration
- 2034-09-23
AI Technical Summary
In the prior art, when protecting metasurface micro-nano structures, commonly used bonding methods cause the refractive index difference of the protective layer to decrease, affecting the phase modulation capability, and irregular filling air gaps between nanostructures affect device performance.
The protective structural design of grooves and alignment marks is used to place the metasurface in the grooves, and precise alignment is achieved through alignment marks, combined with dispensing fixation, and a simple geometry is used to protect the metasurface.
Effective protection of the metasurface micro-nano structure is achieved, avoiding the difficulties of the bonding scheme, reducing costs, and ensuring alignment accuracy and device performance.
Smart Images
Figure CN223065543U_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of optical devices, and particularly relates to a protection structure and an alignment system for protecting a metasurface. Background Art
[0002] Metasurface devices have strong flexibility and degrees of freedom in wavefront regulation and are widely used in fields such as polarization devices, phase modulation devices, amplitude modulation devices, and integration. Damage to micro-nano structures will directly affect the performance parameters of the devices. Therefore, improving the resistance of micro-nano structures to external impacts has become one of the research topics in the industry.
[0003] A commonly used method is to grow a layer of protective material above the micro-nano structure by bonding. Since the refractive index of the protective layer material is higher than that of air, the refractive index difference becomes smaller. For phase modulation type devices, the phase coverage ability will decrease. In addition, irregular air gaps will appear in the filling between nano-structures, affecting the performance of the devices. Summary of the Utility Model
[0004] This application provides a protection structure and an alignment system for protecting a metasurface to at least solve the above technical problems existing in the prior art.
[0005] On the one hand, an embodiment of this application provides a protection structure for protecting a metasurface, including a groove provided inside the protection structure, at least one metasurface, and alignment marks provided on the surface of the protection structure, and the metasurface is placed inside the groove.
[0006] In an implementable manner, the size of the groove is larger than the size of the metasurface.
[0007] In an implementable manner, there are at least two alignment marks, and the two alignment marks are respectively provided at the upper left corner and the upper right corner of the metasurface.
[0008] In an implementable manner, the alignment mark is '+' or 'T'.
[0009] In an implementable manner, the center of the '+' is hollow and light-transmitting, and the outer circle is light-impermeable; there is a hollow area in the middle of the 'T' that is light-transmitting, and the periphery is light-impermeable.
[0010] On the other hand, an embodiment of this application provides an alignment system, which sequentially includes a light source, any one of the above protection structures, a metasurface, a microscopic imaging lens, and a camera from left to right.
[0011] In an implementable manner, the microscopic imaging lens includes a first lens, a microscope, and a second lens.
[0012] In an implementable manner, it further includes a displacement stage, and the displacement stage is used to adjust the protection structure.
[0013] Compared with the prior art, the present application has the following advantages:
[0014] The present application realizes the protection of the metasurface micro-nano structure through a simple geometric structure, avoiding many difficulties in using the bonding scheme for protection and reducing the cost;
[0015] The alignment system of the present application can achieve precise alignment. Description of the Drawings
[0016] Figure 1 It is a schematic diagram of the structure when the metasurface in the protection structure is single-layer in the embodiment of the present application;
[0017] Figure 2 It is a schematic diagram of the structure when the metasurface of the protection structure is double-layer in the embodiment of the present application;
[0018] Figure 3 It is a schematic diagram of the alignment mark in the embodiment of the present application;
[0019] Figure 4 It is an optical path diagram of the alignment system in the embodiment of the present application;
[0020] Figure 5 It is a schematic diagram of the microscope imaging effect of alignment in the embodiment of the present application;
[0021] Figure 6 It is a schematic diagram of the microscope imaging effect with eccentricity misalignment on the front and back surfaces in the embodiment of the present application;
[0022] Figure 7 It is a schematic diagram of the microscope imaging effect with tilt misalignment on the front and back surfaces in the embodiment of the present application. Detailed Embodiments
[0023] The present application will be further described in detail below with reference to the drawings.
[0024] In the description of the present application, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.
[0025] The present application discloses a protection structure for protecting a metasurface, including a groove provided inside the protection structure, at least one metasurface, and alignment marks provided on the surface of the protection structure, and the metasurface is placed in the groove. The size of the groove is larger than the size of the metasurface. There are at least two alignment marks, and the two alignment marks are respectively provided at the upper left corner and the upper right corner of the metasurface.
[0026] The main material of the protection structure can be glass or resin. The grooving on the glass can be achieved by cutting or laser processing. The side wall thickness is determined according to the actual device size and is between 100um and 500um. The top wall thickness is determined according to the size of the structural area of the metasurface. The larger the structural area, the thicker the top wall thickness, generally >100um, to ensure the structural strength of the structure. The resin material can be made by film pressing process. The side wall thickness is determined according to the actual device size and is between 100um and 500um.
[0027] The protection structure has reserved glue dispensing positions, and the glue dispensing areas are designed with frosting. As Figure 1 shown, when single-sided protection is used, the substrate of the metasurface is completely embedded in the protection layer for glue dispensing. As Figure 2 shown, when double-sided protection is used, the protection structure is bonded in two layers, upper and lower. The first layer is bonded at the 1 / 2 position of the substrate. After the first layer is bonded, the second layer is bonded to the other side of the substrate.
[0028] As Figure 3 shown, the protection structure has alignment marks. Typical alignment marks are '+' or 'T' characters, located at the upper left and upper right of the protection structure respectively. The first function of the marks is to distinguish the bonding direction. The second function of the marks is to judge the inclination. The third function of the marks is to align the upper and lower bonding parts. The size of the marks needs to be determined according to the size and position of the alignment marks on the metasurface sample. The alignment marks on the metasurface are the same as the mark characters on the protection structure, with a hollow and complementary shape. The anti-reflection layer is plated on the side of the protection system facing the micro-nano structure, and the material and thickness are determined according to the different working wavelengths of the device.
[0029] As Figure 1 shown is a typical single-layer metasurface protection scheme. The material of the protection structure 11 is selected as glass, with a square groove opened in the middle, and the size extends 0.2mm outward from the metasurface. The side wall thickness of the protection structure 11 is 0.5mm, and the top wall thickness is 200um. The metasurface is placed in the groove. The metasurface includes a base layer 12 and a nano-column structure layer 14. The thickness of the base layer 12 is 0.5mm, and the material selected for the nano-column structure layer 14 is polysilicon, with a height of about 700nm. There is a glue dispensing position 13 in the groove for fixing the base layer and the protection structure. The glue dispensing position 13 is processed with frosting technology.
[0030] As Figure 2The figure shows a typical double-layer super surface protection scheme, where the protection structure 11 includes an upper protective layer 22 and a lower protective layer 24. The super surface includes an upper nanocolumn structure layer, a base layer and a lower nanocolumn structure layer, where the upper nanocolumn structure layer is placed in the upper protective layer 22, and the lower nanocolumn structure layer is placed in the lower protective layer 24. The upper protective layer 22 and the lower protective layer 24 are bonded by glue, and a glue point 21 is provided in the upper protective layer 22 and the lower protective layer 24. The side walls of the base layer are fixed to the upper protective layer 22 and the lower protective layer 24, respectively, and glue can be used for bonding. The glue point 21 is frosted.
[0031] like Figure 3 As shown in FIG. 1 , an opaque alignment mark is left on the surface of the protective structure 11. Figure 4 As shown, the upper left corner alignment mark is 'X' and the upper right corner mark is 'T'. Figure 4 The upper left corner of the metasurface 43 shown in the figure also has an alignment mark '+', but the center of the cross is hollowed out and transparent, and the outer circle is opaque. The upper right corner also has an alignment mark 'T', with a hollow area in the middle of the mark that is transparent and the outer circle is opaque. After the protective structure is fully aligned with the metasurface, the alignment mark of the protective structure completely overlaps with the hollow area of the alignment mark of the metasurface.
[0032] The present application also discloses an alignment system, which includes, from left to right, a light source 41, any of the above-mentioned processed protective structures 42, a metasurface 43, a microscopic imaging lens and a camera. The light source 41 is a single-wavelength incoherent parallel light, the wavelength of which can be 660nm, 532nm, etc., and is used to provide illumination for the alignment optical path. The microscopic imaging lens includes a first lens 44, a microscope 45 and a second lens 46, which together constitute an imaging system for observing the alignment status. The camera 47 is a CCD, which is used to record the current image for the computer system to analyze and determine the adjustment of the six-axis system to ensure complete alignment. It also includes a displacement stage, which can be a six-axis displacement stage, for adjusting the protective structure.
[0033] like Figure 4 As shown, to the right of the light source 41 is a processed protective structure 42, and the optical axis is located at the center of the device and is vertical. To the right of the processed protective structure 42 is a metasurface 43, and the optical axis is located at the center of the metasurface and is vertical. To the right of the metasurface is a microscopic optical path composed of a first lens 44, a microscope 45, and a second lens 46, which is used to image the front part of the system. To the right of the imaging system is a camera, which is used to record images and provide a basis for adjusting the alignment adjustment system. The six-axis translation stage is used to adjust the relative positions between devices to ensure alignment accuracy.
[0034] like Figure 6 The figure shows the effect when the protective structure deviates from the upper left of the optical axis. At this time, the protective structure needs to be adjusted to the lower right by the translation stage. Figure 7The figure shows a schematic diagram when the protection structure is tilted and rotated. At this time, the computer analyzes the image to automatically adjust the displacement stage, or the operator manually adjusts the displacement stage. Until the modulated image reaches the effect shown in Figure 5 When the shown effect is achieved, it is determined that the alignment is completed. At this time, the dispensing operation is carried out, and after the glue is cured, the assembly of the protective layer is completed.
[0035] The above is only the specific implementation manner of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present disclosure can easily think of changes or substitutions, which should be covered within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.
Claims
1. A protective structure for protecting a metasurface, characterized in that: It includes a groove provided inside the protection structure, at least one metasurface, and alignment marks provided on the surface of the protection structure, and the metasurface is placed inside the groove.
2. The protective structure for protecting a metasurface according to claim 1, wherein: The size of the groove is larger than the size of the metasurface.
3. A protection structure for protecting a metasurface according to claim 1, characterized in that: There are at least two alignment marks, and the two alignment marks are respectively provided at the upper left corner and the upper right corner of the metasurface.
4. A protection structure for protecting a metasurface according to claim 3, characterized in that: The alignment marks are '+' or 'T'.
5. A protective structure for protecting a metasurface according to claim 4, characterized in that: The center of the '+' is hollow and light-transmitting, and the outer ring is light-impermeable; there is a hollow area in the middle of the 'T' that is light-transmitting, and the periphery is light-impermeable.
6. An alignment system, characterized in that, From left to right, it sequentially includes a light source, any one of the protection structures in claims 1-5, a metasurface, a microscopic imaging lens, and a camera.
7. The alignment system according to claim 6, characterized in that: The microscopic imaging lens includes a first lens, a microscope, and a second lens.
8. The alignment system according to claim 6, wherein: It further includes a displacement stage, and the displacement stage is used to adjust the protection structure.