Memory alloy micro-nano structure and manufacturing method

Abstract

This invention discloses a shape memory alloy micro / nano structure and its manufacturing method, relating to the field of optical structural devices. The shape memory alloy micro / nano structure uses shape memory alloy material and can achieve wide-spectrum modulation. The manufacturing method includes the following steps: Step 1, fabricating a micro / nano structure mold; Step 2, coating the upper surface of a shape memory alloy block with photoresist, heating the shape memory alloy block and photoresist, and imprinting the photoresist using the micro / nano structure mold to create a micro / nano structure mask; Step 3, processing the shape memory alloy micro / nano structure on the surface of the shape memory alloy block using ion beam etching. This shape memory alloy micro / nano structure avoids the limitation of diffraction limit preventing the fabrication of smaller structures, and avoids the shortcomings of poor memory capacity and low precision caused by relying on external force to stretch the micro / nano structure. It solves the problem of the fixed and narrow service bands of existing optical structural devices, which restricts their application scenarios.

Description

Technical Field

[0001] This invention relates to the field of optical structural devices, and in particular to a shape memory alloy micro / nano structure and its manufacturing method. Background Technology

[0002] In recent years, optical structural devices have been developing towards greater spectral modulation range, cross-band functionality, and adaptability to complex and changing service environments. In nature, the structure on a chameleon's skin possesses the characteristic of broad-spectrum modulation. The geometric features of its micro / nano structures can change with environmental changes, thus altering the modulated light wavelength and changing the skin's color accordingly. This ability to memorize and modify light modulation has significant practical value. Just as a chameleon's skin returns to its corresponding color when the environment changes along a path and returns to its origin, memorized optical micro / nano structures will play a crucial role in broad-spectrum modulation. The size of the micro / nano structure determines the service wavelength. When the size of the optical micro / nano structure changes, structural color optics can display different colors, and filters can filter light of different wavelengths. This memorized and modifyable micro / nano structure possesses broad-spectrum modulation capabilities across wavelengths and will play a key role in optical displays and intelligent optoelectronic systems.

[0003] Current variable optical micro / nano structures and manufacturing technologies mainly target polymer liquid crystal materials. The first method is to form micro / nano structures by changing the refraction of the material, and the second method is to form surface relief micro / nano structures on the material by imprinting.

[0004] Regarding changes in the refractive index of materials, researchers have used photographic techniques and the properties of liquid crystal materials to induce periodically varying refractive indices within these materials, which they then use as micro / nano structures. Because liquid crystal materials possess excellent elasticity, applying force to stretch the optoelectronic material alters its refractive index, thereby enabling the manipulation of light across different wavelengths.

[0005] In the field of nanoimprinted relief structures, researchers first fabricate a mold, and then replicate the micro- and nanostructures on the mold surface onto a softer polymer by heating and applying pressure. Since polymers typically possess excellent elasticity, stretching the material also allows for alteration of the size and morphology of the surface micro- and nanostructures, thus enabling broad-spectrum manipulation.

[0006] As mentioned above, the method of forming micro- and nano-structures by changing the refractive index of materials can only be achieved in liquid crystal materials. Furthermore, the formation of such micro- and nano-structures relies on optical photography techniques, and is therefore limited by the diffraction limit, preventing the fabrication of structures with smaller scales. In addition, relying on external stretching to achieve changes in micro- and nano-structures has drawbacks such as poor memory and low precision, which limits its application in optical systems such as displays and filters. Summary of the Invention

[0007] To address the above technical problems, this invention provides a shape memory alloy micro / nano structure and manufacturing method, which avoids the limitation of diffraction limit that prevents the fabrication of smaller structures, and avoids the disadvantages of poor shape memory and low precision caused by relying on external force to stretch the micro / nano structure.

[0008] To achieve the above objectives, the present invention provides the following solution:

[0009] This invention provides a shape memory alloy micro / nano structure, which is made of shape memory alloy material and can achieve wide-spectrum tunability.

[0010] Preferably, the shape memory alloy micro / nano structure includes multiple micro / nano units, wherein the micro / nano units are triangular pyramidal structures or quadrangular pyramidal structures.

[0011] This invention also provides a method for manufacturing shape memory alloy micro / nano structures, comprising the following steps:

[0012] Step 1: Fabricate a micro / nano structure mold;

[0013] Step 2: Coat the upper surface of the shape memory alloy block with photoresist, heat the shape memory alloy block and the photoresist, and use the micro-nano structure mold to imprint the photoresist to create a micro-nano structure mask.

[0014] Step 3: The shape memory alloy micro / nano structure is fabricated on the surface of the shape memory alloy block by ion beam etching.

[0015] Preferably, in step one, a micro-nano structure is fabricated on the molding material to create a micro-nano structure molding die, and the micro-nano structure is transferred onto a hydrophobic material using the micro-nano structure molding die to create the micro-nano structure mold.

[0016] Preferably, in step one, the molding material is nickel phosphide, copper, or aluminum, and micro / nano structures are machined on the upper surface of the molding material using single-point turning, milling, high-speed flying cutting, or ultrasonic vibration-assisted cutting methods.

[0017] Preferably, in step one, the micro-nano structure mold is placed on a horizontal platform, a sleeve adapted to the micro-nano structure mold is installed on the micro-nano structure mold, the hydrophobic material is poured into the sleeve to form a combined device, the combined device is left to stand for 30 minutes and then placed in a constant temperature oven at 85°C for 2 hours. After the hydrophobic material has solidified, the hydrophobic material is separated from the micro-nano structure mold. The lower surface of the hydrophobic material replicates the micro-nano structure on the upper surface of the micro-nano structure mold, thereby producing the micro-nano structure mold.

[0018] Preferably, in step two, a photoresist with a thickness of 1 to 10 micrometers is first spin-coated onto the upper surface of the shape memory alloy block. Then, the shape memory alloy block and the photoresist are preheated to 65°C, heated to 85°C, and then the photoresist is imprinted using the micro-nano structure mold and held for more than 30 minutes. Subsequently, the photoresist is naturally cooled to below the Tg point of the photoresist, and the micro-nano structure mold is separated from the photoresist to fabricate the micro-nano structure mask.

[0019] Preferably, in step three, the shape memory alloy block with the micro / nano structure mask on its surface is placed in an ion beam etching vacuum chamber, and the micro / nano structure is transferred from the micro / nano structure mask to the shape memory alloy block by bombardment with the ion beam, thereby processing the shape memory alloy micro / nano structure.

[0020] The present invention achieves the following technical effects compared to the prior art:

[0021] The shape memory alloy micro / nano structure of this invention uses shape memory alloy material and can achieve wide-spectrum control. High-quality micro / nano structures are manufactured on the surface of shape memory alloy material through a combination of mold processing, imprinting, and ion beam etching. It avoids the limitation of diffraction limit that prevents the fabrication of smaller structures. By utilizing the two-way variable memory characteristics of shape memory alloy, the characteristic size of the micro / nano structure can be changed in a memorized manner, thereby achieving wide-spectrum control. This avoids the shortcomings of poor memorability and low precision caused by relying on external force to stretch the micro / nano structure. It also solves the problem of the limited application scenarios caused by the fixed and narrow service bands of existing optical structure devices. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A flowchart illustrating the manufacturing method of shape memory alloy micro / nano structures provided by this invention.

[0024] Explanation of reference numerals in the attached figures: 1. Molding material; 2. Diamond cutting tool; 3. Shape memory alloy block; 4. Photoresist; 5. Micro / nano structure mold; 6. Micro / nano structure mask; 7. Shape memory alloy micro / nano structure. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] The purpose of this invention is to provide a shape memory alloy micro / nano structure and manufacturing method, which avoids the limitation of diffraction limit that prevents the fabrication of smaller structures, and avoids the disadvantages of poor shape memory and low precision caused by relying on external force to stretch the micro / nano structure to achieve changes.

[0027] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] like Figure 1 As shown, this embodiment provides a shape memory alloy micro / nano structure 7, which is made of shape memory alloy material and can achieve wide spectrum modulation.

[0029] The shape memory alloy micro / nano structure 7 includes multiple micro / nano units, which are triangular or quadrangular pyramidal structures.

[0030] In this embodiment, the shape memory alloy micro / nano structure 7 is a trench-type and two-dimensional array-type micro / nano structure with unit sizes ranging from hundreds of nanometers to several micrometers. The micro / nano trenches can be V-shaped trenches or sawtooth-shaped trenches. The two-dimensional array micro / nano structure is generated orthogonally from parallel trenches at different angles. Therefore, it can be a triangular pyramidal micro / nano structure or a square pyramidal micro / nano structure.

[0031] This embodiment also provides a method for manufacturing a shape memory alloy micro / nano structure 7, including the following steps:

[0032] Step 1: Fabricate the micro / nano structure mold 5;

[0033] Step 2: Coat the upper surface of the shape memory alloy block 3 with photoresist 4, heat the shape memory alloy block 3 and photoresist 4, and use a micro-nano structure mold 5 to imprint the photoresist 4, thereby creating a micro-nano structure mask 6.

[0034] Step 3: The shape memory alloy micro / nano structure 7 is fabricated on the surface of the shape memory alloy block 3 by ion beam etching.

[0035] In this embodiment, a high-quality micro-nano structure is fabricated on the surface of a shape memory alloy material through a composite process of mold processing, imprinting, and ion beam etching. This avoids the limitation of being unable to fabricate smaller structures due to the diffraction limit. By utilizing the two-way variable memory characteristics of shape memory alloys, the characteristic dimensions of the micro-nano structure can be changed in a memorable manner, thereby achieving wide-spectrum control. This avoids the shortcomings of poor memorability and low precision caused by relying on external force to stretch the micro-nano structure, and solves the problem of the limited application scenarios caused by the fixed and narrow service bands of existing optical structure devices.

[0036] Specifically, in step one, micro-nano structures are fabricated on molding material 1 to create a micro-nano structure mold. The micro-nano structure is then transferred onto a hydrophobic material using the micro-nano structure mold to create a micro-nano structure mold 5. By creating a hydrophobic micro-nano structure mold 5, demolding is facilitated during the subsequent fabrication of the micro-nano structure mask 6.

[0037] In this specific embodiment, in step one, the molding material 1 is nickel phosphide, copper, or aluminum. It should be noted that the molding material 1 is not limited to the above-mentioned materials with excellent machinability. Micro-nano structures are machined on the upper surface of the molding material 1 using single-point turning, milling, high-speed flying cutting, or ultrasonic vibration-assisted cutting methods. It should be noted that the processing methods for micro-nano structures on the molding material 1 are not limited to the above methods.

[0038] The micro-nano structures involved in this embodiment have complex morphologies, with V-shaped and sawtooth cross-sectional contours belonging to 3D morphology. Therefore, complex micro-nano structures need to be created with high quality through mechanical processing. Specifically, the micro-nano structures in this embodiment are generated on the molding material 1 by scribing with a diamond tool 2.

[0039] In this specific embodiment, in step one, the micro-nano structure mold is placed on a horizontal platform, a sleeve adapted to the micro-nano structure mold is installed on the micro-nano structure mold, and hydrophobic material is poured into the sleeve to form a combined device. After the combined device is left to stand for 30 minutes, it is placed in a constant temperature oven at 85°C for 2 hours. After the hydrophobic material is cured, the hydrophobic material is separated from the micro-nano structure mold. The lower surface of the hydrophobic material replicates the micro-nano structure on the upper surface of the micro-nano structure mold, thereby producing the micro-nano structure mold 5.

[0040] In this embodiment, the hydrophobic material is PDMS. The prepared PDMS material (the A / B mixing ratio is selected according to the hardness requirement) is poured into the sleeve. It should be noted that the hydrophobic material in this embodiment is not limited to PDMS.

[0041] In step two, the micro-nano structure on the lower surface of the hydrophobic material is transferred to the surface of the photoresist 4 to form a micro-nano structure mask 6. Specifically, a photoresist 4 with a thickness of 1 to 10 micrometers is first spin-coated on the upper surface of the shape memory alloy block 3. Then, the shape memory alloy block 3 and the photoresist 4 are preheated to 65°C and heated to 85°C. The photoresist 4 is then imprinted using a micro-nano structure mold 5 and held for more than 30 minutes. After that, it is naturally cooled down to below the Tg point of the photoresist 4. The micro-nano structure mold 5 is then separated from the photoresist 4 to produce the micro-nano structure mask 6.

[0042] In this embodiment, the shape memory alloy block 3 is made of nickel-titanium alloy. It should be noted that the material of the shape memory alloy block 3 in this embodiment is not limited to nickel-titanium alloy.

[0043] Specifically, in step three, the shape memory alloy block 3 with the micro / nano structure mask 6 fabricated on its surface is placed in the ion beam etching vacuum chamber. The micro / nano structure is transferred from the micro / nano structure mask 6 to the shape memory alloy block 3 under the bombardment of the ion beam, thereby fabricating the shape memory alloy micro / nano structure 7. During ion beam etching, morphological errors during the micro / nano structure transfer process are reduced by controlling process parameters such as working gas pressure and ion beam current.

[0044] In this embodiment, the shape-memory change characteristic of shape-memory alloys is utilized to fabricate shape-memory alloy micro / nanostructures 7 on their surface, achieving the memorized changeability of shape-memory alloy micro / nanostructures 7. Since the service wavelength of micro / nanostructures is related to their structural size, this embodiment proposes a method to achieve cross-band broadband spectral control using the size change of shape-memory alloy micro / nanostructures 7. Because shape-memory alloy micro / nanostructures 7 with memorized deformation can be fabricated, the broadband spectral control function also possesses memory properties. Furthermore, the surface of difficult-to-machine materials typically cannot be directly machined to achieve complex structures at the micro / nano scale. The method proposed in this embodiment can be applied to the high-precision machining of micro / nanostructures on the surface of other difficult-to-machine materials.

[0045] This specification uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for manufacturing micro / nano structures of shape memory alloys, characterized in that, The shape memory alloy micro-nano structure is made of shape memory alloy material and can achieve wide spectrum control. The shape memory alloy micro-nano structure includes multiple micro-nano units, and the micro-nano units are triangular pyramidal structures or quadrangular pyramidal structures. The manufacturing method includes the following steps: Step 1: Fabricate a micro / nano structure mold; Step 2: Coat the upper surface of the shape memory alloy block with photoresist, heat the shape memory alloy block and the photoresist, and use the micro-nano structure mold to imprint the photoresist to create a micro-nano structure mask. Step 3: The shape memory alloy micro / nano structure is fabricated on the surface of the shape memory alloy block by ion beam etching.

2. The method for manufacturing shape memory alloy micro / nano structures according to claim 1, characterized in that, In step one, micro-nano structures are fabricated on the molding material to create a micro-nano structure mold. The micro-nano structure is then transferred onto a hydrophobic material using the micro-nano structure mold to create the micro-nano structure mold.

3. The method for manufacturing shape memory alloy micro / nano structures according to claim 2, characterized in that, In step one, the molding material is nickel phosphide, copper, or aluminum, and micro-nano structures are machined on the upper surface of the molding material using single-point turning, milling, high-speed flying cutting, or ultrasonic vibration-assisted cutting methods.

4. The method for manufacturing shape memory alloy micro / nano structures according to claim 2, characterized in that, In step one, the micro-nano structure mold is placed on a horizontal platform, and a sleeve adapted to the micro-nano structure mold is installed on the micro-nano structure mold. The hydrophobic material is poured into the sleeve to form a combined device. After the combined device is left to stand for 30 minutes, it is placed in a constant temperature oven at 85°C and heated for 2 hours. After the hydrophobic material is cured, the hydrophobic material is separated from the micro-nano structure mold. The lower surface of the hydrophobic material replicates the micro-nano structure on the upper surface of the micro-nano structure mold, thereby producing the micro-nano structure mold.

5. The method for manufacturing shape memory alloy micro / nano structures according to claim 1, characterized in that, In step two, a photoresist with a thickness of 1 to 10 micrometers is first spin-coated onto the upper surface of the shape memory alloy block. Then, the shape memory alloy block and the photoresist are preheated to 65°C and heated to 85°C. The photoresist is then imprinted using the micro-nano structure mold and held for more than 30 minutes. After that, the photoresist is allowed to cool naturally to below the Tg point of the photoresist. The micro-nano structure mold is then separated from the photoresist to fabricate the micro-nano structure mask.

6. The method for manufacturing shape memory alloy micro / nano structures according to claim 1, characterized in that, In step three, the shape memory alloy block with the micro / nano structure mask on its surface is placed in an ion beam etching vacuum chamber. The micro / nano structure is transferred from the micro / nano structure mask to the shape memory alloy block by bombardment with the ion beam, thereby processing the shape memory alloy micro / nano structure.

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