阅读说明：本技术 一种具有纳米复合结构的光学防伪标识 (Optical anti-counterfeiting mark with nano composite structure ) 是由 潘安练 李梓维 黄明 于 2020-11-24 设计创作，主要内容包括：本发明公开了一种具有纳米复合结构的光学防伪标识,采用如下方法制得,采用如下方法制得,步骤一：制备纳米复合结构,所述纳米复合结构包括衬底以及衬底上方的金纳米结构层,衬底包括单晶硅片或金属氧化物制成,步骤二：纳米复合结构阵列组合成任意图形；步骤三：利用白光照射所述图形,对光进行明场与暗场区分,从而显示出不同的明暗场图案而实现光学防伪。本发明操作简单,难度小,实现可能性高,实际生产价值更大。(The invention discloses an optical anti-counterfeiting mark with a nano composite structure, which is prepared by the following method: preparing a nano composite structure, wherein the nano composite structure comprises a substrate and a gold nano structure layer above the substrate, the substrate comprises a monocrystalline silicon wafer or a metal oxide, and the second step comprises the following steps: combining the nano composite structure array into any pattern; step three: the pattern is irradiated by white light, and bright field and dark field of the light are distinguished, so that different bright and dark field patterns are displayed, and optical anti-counterfeiting is realized. The method has the advantages of simple operation, small difficulty, high realization possibility and higher actual production value.)

1. An optical anti-counterfeiting mark with a nano composite structure is characterized by being prepared by the following method, comprising the following steps: preparing a nano composite structure, wherein the nano composite structure comprises a substrate and a gold nano structure layer above the substrate, the substrate comprises a monocrystalline silicon wafer or a metal oxide, and the second step comprises the following steps: combining the nano composite structure array into any pattern; step three: the pattern is irradiated by white light, and bright field and dark field of the light are distinguished, so that different bright and dark field patterns are displayed, and optical anti-counterfeiting is realized.

2. The optical anti-counterfeiting mark with the nano-composite structure according to claim 1, wherein the gold nano-structure layer is a spiral structure or a cylindrical three-dimensional structure.

3. The optical anti-counterfeiting mark with the nano-composite structure according to claim 2, wherein the spiral structure is a single-turn Archimedes spiral grating structure and is divided into a clockwise structure or a counterclockwise structure, the spiral starting radius of the spiral layer is 100nm, the grating width is 100nm, the grating interval is 200nm, and the silicon wafer is a <100> or <111> crystal orientation single-side polished intrinsic monocrystalline silicon wafer; the pattern is composed according to a plurality of clockwise spiral units and counterclockwise spiral units according to a predetermined design, and the interval between the adjacent spiral units is 1000 nm.

4. The optical anti-counterfeiting mark with the nano-composite structure according to claim 1, wherein the metal oxide is one of aluminum oxide, magnesium oxide, calcium oxide or potassium oxide.

5. The optical anti-counterfeit mark with nano-composite structure as claimed in claim 3 or 4, wherein the nano-composite structure is prepared by selecting a silicon wafer or a metal oxide as a substrate, and exposing the optimized nano-composite structure on a previously prepared silicon wafer by using an electron beam exposure system through nano-pattern generation software.

Technical Field

The invention belongs to the technical field of optical anti-counterfeiting materials, and particularly relates to an optical anti-counterfeiting mark with a nano composite structure.

Background

At present, special fluorescent materials are designed into patterns or characters, and then are identified by naked eyes or professional instruments under the irradiation of an external light source, and the anti-counterfeiting material is applied to various emerging fields according to the unique performance of the anti-counterfeiting material, including the fields of food safety, industrial manufacturing, medical treatment, military affairs and the like. The existing fluorescent anti-counterfeiting material is mainly innovated in the aspect of physical properties of the fluorescent material, such as diffraction optical anti-counterfeiting: conventional holographic gratings are surface gratings of reflective transparent materials, while the diffractions can be hidden in microlayers with different optical indices or in transparent materials. It has a micro-grating structure finer than that of hologram and may be used as one layer of optical film as anti-fake optical mark. The anti-counterfeiting method is currently applied to the anti-counterfeiting of the second-generation identity card, the front face of the icon at the upper left corner of the second-generation identity card is seen as lake green, but when the plane of the icon is rotated by 90 degrees, the icon is completely changed into another color; for example, the patent CN201310059481.9 of the present invention is a polymer ultraviolet fluorescent material that can be used in anti-counterfeiting technology, and relates to a polymer fluorescent material and a preparation method thereof. The invention provides a polymer luminescent material which introduces micromolecule organic luminescent groups with definite structures into the side chains of stable polyarylether non-conjugated polymers and a preparation method thereof.

As also shown in the prior art CN111474613A, the invention is an optical anti-counterfeit mark with a nano composite structure and its application, and discloses an optical anti-counterfeit mark with a nano composite structure, which comprises a gold nano spiral layer, a molybdenum disulfide luminescent layer, a silica thin layer, a gold thin layer and a silicon wafer in sequence from top to bottom, wherein the gold nano spiral layer is a two-turn archimedes spiral grating structure, the light absorption efficiency of a semiconductor material is effectively regulated and controlled by using the local plasmon resonance effect of the gold nano structure, and the fluorescence emission polarization can be regulated by using monochromatic polarization laser to excite the material, thereby realizing high-precision and high-safety fluorescence anti-counterfeit.

In the prior art, the anti-counterfeiting method by using fluorescence is urgently needed to be developed by using an optical anti-counterfeiting technology of detecting by using a common incandescent lamp, wherein polarized white light irradiates different structures and scatters signals with different intensities to realize the anti-counterfeiting, because some fluorescent materials need to be selected and some fluorescent materials need to be excited by using laser with specific wavelengths, the operation is troublesome and the realization difficulty is high. At present, the prior art does not have a technology for realizing anti-counterfeiting by using wide-spectrum white light reflection on different structures.

Disclosure of Invention

The invention provides an optical anti-counterfeiting mark with a nano composite structure, which is made of a geometric figure formed by combining a plurality of optical anti-counterfeiting nano composite structure arrays.

In order to achieve the purpose, the invention adopts the technical scheme that: an optical anti-counterfeiting mark with a nano composite structure is prepared by the following method, comprising the following steps: preparing a nano composite structure, wherein the nano composite structure comprises a substrate and a gold nano structure layer above the substrate, the substrate comprises a monocrystalline silicon wafer or a metal oxide, and the second step comprises the following steps: combining the nano composite structure array into any pattern; step three: the pattern is irradiated by white light, and bright field and dark field of the light are distinguished, so that different bright and dark field patterns are displayed, and optical anti-counterfeiting is realized.

Further, the gold nanostructure layer is of a spiral structure or a cylindrical three-dimensional structure.

Furthermore, the spiral structure is a single-turn Archimedes spiral grating structure and is divided into a clockwise structure or a counterclockwise structure, the spiral initial radius of the spiral layer is 100nm, the grating width is 100nm, the grating interval is 200nm, and the silicon wafer is a <100> or <111> crystal orientation single-side polished intrinsic monocrystalline silicon wafer; the pattern is composed according to a plurality of clockwise spiral units and counterclockwise spiral units according to a predetermined design, and the interval between the adjacent spiral units is 1000 nm.

Further, the metal oxide is one of aluminum oxide, magnesium oxide, calcium oxide and potassium oxide.

Further, the nano-composite structure is prepared by a method comprising the steps of firstly selecting a silicon wafer or a metal oxide as a substrate, and exposing the designed and optimized nano-composite structure on a prepared silicon wafer through nano-pattern generation software by using an electron beam exposure system.

The principle of the invention is as follows: when the structures are different, different polarizations can be generated, different reflected lights can be generated under different polarization effects, so that different bright and dark field patterns can be displayed, and different patterns can be reflected by different structures through pattern comparison under the irradiation light in different ranges of the bright and dark fields, so that high-precision and high-safety optical anti-counterfeiting is realized.

The invention has the beneficial effects that:

the nano composite structure of the invention is based on the physical principle of light reflection, realizes different optical images by designing a gold nano spiral structure, utilizing white light reflection and reflecting through different structures without involving light absorption and re-reflection, thereby generating luminous patterns with different 'plain texts' and 'dark texts' and realizing optical anti-counterfeiting. The structure is simple to operate and easy to realize, can realize flexible light emission range regulation and control, realizes different patterns through regulation and control of different light ranges, and has great application potential in the fields of optical anti-counterfeiting marks, photoelectricity and biomedicine.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art and the advantages of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other structures can be obtained according to the structures shown in the drawings without creative efforts for those skilled in the art.

FIG. 1 is a schematic structural view of an integral composite structure of the present invention.

Fig. 2 is a dimension parameter of the gold nano-helical structure.

Fig. 3 is a micrograph of the composite structure.

FIG. 4 is an optical image in dark field conditions with different 1/4 circle illumination sizes.

Fig. 5 shows optical images of different semi-circle illumination sizes under white light illumination.

Detailed Description

The specific embodiment of the invention:

as shown in fig. 1, the optical anti-counterfeit mark with a nano composite structure in this embodiment mainly includes a silicon substrate and a spiral structure (the three-dimensional structure of this embodiment is a spiral structure), the silicon substrate includes a silicon dioxide sheet 2 and a base 3, the base 3 is a single-crystal silicon wafer, a gold nano spiral layer 1 is disposed above the silicon substrate, the gold nano spiral layer is a single-turn archimedes spiral grating structure, the initial radius of the spiral is about 100nm, the grating width is about 100nm, the grating pitch is about 200nm, the thickness is about 30nm, and the silicon wafer is a <100> or <111> crystal orientation single-side polished intrinsic single-crystal silicon wafer. The fluorescent anti-counterfeiting mark is prepared by combining a plurality of optical anti-counterfeiting nano composite structure arrays into a geometric figure, the geometric figure is divided into a left-handed structure and a right-handed structure, and the distance between each spiral unit is about 1100 nm.

Then spin-coating PMMA 950K glue on the surface of the silicon substrate, wherein the glue homogenizing parameter is 3000r/s, and the glue homogenizing time is 60 s; then placing the substrate on a hot plate for drying, setting the temperature of the hot plate to be 180 ℃ and drying for 5 minutes, utilizing an electron beam exposure system to design an optimized nano composite structure, exposing the nano composite structure on the prepared dried substrate through nano pattern generation software, clamping the exposed substrate by using tweezers, soaking the substrate in developing and fixing liquid for 60s to form an exposed pattern, then evaporating a 40nm gold film on the prepared substrate by using an electron beam evaporation system, soaking the substrate in acetone, stripping the substrate after 2h, and drying the substrate by using a nitrogen gun to obtain the final composite structure.

Characterization of the nanocomposite structure of this example:

referring to fig. 2, fig. 2 shows the dimensional parameters of the gold spiral structure, wherein the initial radius of the spiral is about 100nm, the grating width is about 100nm, and the grating pitch is about 200 nm.

Referring to fig. 3, the nanocomposite structure array assembly geometry of the present embodiment is depicted, including the clockwise-rotated helical composite structure forming letter "bkn", and the other helical composite structure arrays, all of which are counterclockwise-rotated, are arranged around "bkn", from which it is apparent that different helical structures, different polarization effects will produce different luminous patterns after white light irradiation.

Referring to fig. 4, a fluorescent anti-counterfeit label is combined into a geometric figure by using the nano composite structure unit array of the embodiment, the geometric figure is composed of a clockwise spiral unit and a counterclockwise spiral unit, and the distance between the spiral units is 1.1 mm. In the geometric figure, a plurality of spiral units form three characters 'bkn', under a dark field, the polarized light reflected by the clockwise rotating gold nano spiral particles is different from the polarized light reflected by the counterclockwise rotating gold nano spiral particles, and different luminous images can be formed due to different polarized lights reflected by different structures.

Referring to fig. 5, as in fig. 4, the fluorescent anti-counterfeit mark is combined into a geometric figure by using the nano composite structure unit array of the embodiment, the geometric figure is composed of a clockwise spiral unit and a counterclockwise spiral unit, the 'bkn' is a clockwise single-turn archimedes coil, and the rest nano spirals are precisely designed into the counterclockwise spiral direction. In the geometric figure, a plurality of spiral units form three characters 'bkn', under the irradiation of white light, clockwise rotating gold nano spiral particles hardly emit light, only counterclockwise gold nano spiral structures different from 'bkn' emit fluorescence, and under different irradiation ranges, the structures have different polarized light because different structures reflect different polarized light.

The method is simple to operate, low in difficulty, high in realization possibility and higher in actual production value. The nano composite structure is applied to optical anti-counterfeiting, can realize micron-sized optical resolution, and can greatly improve the resolution compared with the prior technologies such as laser anti-counterfeiting, optical etching anti-counterfeiting and the like. The technology is excited by polarized light, has the advantages of high resolution and high safety, and the related fluorescent anti-counterfeiting technology can be widely applied to products such as hard disks, electronic chips and the like and can also be applied to high-precision anti-counterfeiting of hard disk data and the like.

The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.