KR102377294B1 - Reflective type film for anti-counterfeiting and manufacturing method for the same - Google Patents

Abstract

The present invention is a base; A diffractive optical element layer located on the base and including a diffraction pattern, wherein the diffraction pattern includes a plurality of layers, and the minimum spacing (△h) in the thickness direction between the plurality of layers is 20. It relates to a reflective anti-counterfeiting film having a thickness of 50 nm to 50 nm and a method of manufacturing the same.

Description

Reflective anti-counterfeiting film and manufacturing method thereof {REFLECTIVE TYPE FILM FOR ANTI-COUNTERFEITING AND MANUFACTURING METHOD FOR THE SAME}

The present invention relates to a method of manufacturing a reflective anti-counterfeiting film that can implement an image for authenticity determination using an authenticity determination pattern.

Counterfeiting of expensive items, including software, media, and storage media containing them, has been a social and economic issue since the past.

Recently, counterfeit products have been increasing significantly not only in the media and expensive items mentioned above, but also in household items that can be commonly purchased in daily life.

These counterfeit products cause great damage to companies and further harm consumers. Furthermore, counterfeit products have the problem of disrupting the market, which is the core of capitalism.

To solve the forgery problem, technologies such as holograms have been applied in the past.

A hologram is a medium that records interference stripes that reproduce three-dimensional images, and is manufactured using the principles of holography.

More specifically, the hologram reproduces (or implements) a specific image by incident (or radiating) reproduced light having the same frequency, wavelength, and phase as the reference light onto the interference stripes at a specific angle.

However, the hologram has a fundamental limitation because the reproduced light must have the same phase, wavelength, and frequency as the reference light.

Furthermore, there are limits to the information that can be recorded in holograms, making it difficult to produce sophisticated holograms.

Furthermore, due to the difficulty of production, holograms are usually located only on part of the product or part of the product packaging, so there is a problem that they can be easily removed.

In order to improve the problems of the hologram, a technology or product that records information on the anti-counterfeiting film itself has been developed using a semiconductor process, especially a nanoimprinting manufacturing method using a micropattern process.

However, since the anti-counterfeiting film uses a semiconductor process, productivity decreases as the number of fine pattern processes increases.

More specifically, as the number of fine pattern processes increases, clearer and brighter information can be recorded, but low productivity dramatically increases the unit cost of the anti-counterfeiting film itself.

As a result, a problem arises where the cost of the film itself to protect the product exceeds the product price.

On the other hand, if the number of fine pattern processes decreases, the clarity of the recorded information decreases and the light efficiency decreases.

The present invention is an invention to solve the problems of the conventional anti-counterfeiting film described above, and its purpose is to provide an anti-counterfeiting film with excellent productivity while securing maximum light efficiency, and a method for manufacturing the same.

Another object of the present invention is to provide an anti-counterfeiting film in which the height of the information pattern portion in which information is stored is controlled, and a method of manufacturing the same.

Another object of the present invention is to provide an anti-counterfeiting film that can clearly embody information with complex images and a method of manufacturing the same.

An anti-counterfeiting film according to an embodiment of the present invention for achieving the above object includes a base; A diffractive optical element layer located on the base and including a diffraction pattern, wherein the diffraction pattern includes a plurality of layers, and the minimum spacing (△h) in the thickness direction between the plurality of layers is 20. It is characterized in that it is from 50 nm.

At this time, the total height (H) of the diffraction pattern is preferably 200 to 330 nm.

At this time, it is preferable to include a residue located between the diffraction pattern and the base.

At this time, the base is preferably transparent PET.

At this time, the diffractive optical element layer is preferably made of urethane-based or acrylic-based resin.

Meanwhile, an adhesive layer, an adhesive layer, or a double-sided tape may be additionally included in the lower part of the base.

Meanwhile, a printing layer may be additionally included on the top and/or bottom of the base.

A method of manufacturing an anti-counterfeiting film according to an embodiment of the present invention to achieve the above object includes the steps of (a) converting the original image image into a DOE (diffraction optical elements) mask; (b) separating the DOE mask into three DOE unit masks; (c) manufacturing each of the three DOE unit masks; (d) manufacturing a master stamp including a diffraction pattern on the silicon substrate by sequentially exposing and etching each of the DOE unit masks; (e) imprinting a diffractive optical element using the master stamp.

A reflective diffractive optical element according to an embodiment of the present invention for achieving the above object includes a diffraction pattern, the diffraction pattern includes a plurality of layers, and the minimum gap in the thickness direction between the plurality of layers (Δh) is characterized in that it is 20 to 50 nm.

At this time, the total height (H) of the diffraction pattern is preferably 200 to 330 nm.

According to the present invention, it is possible to provide an anti-counterfeiting film that has excellent light efficiency characteristics, provides clear information, and has high productivity, and a method of manufacturing the same.

Specifically, the anti-counterfeiting film according to the present invention can provide an anti-counterfeiting film that can provide clear information with high light efficiency.

In addition, according to the manufacturing method of the anti-counterfeiting film according to the present invention, the manufacturing method of the anti-counterfeiting film with excellent productivity and light efficiency characteristics can be manufactured at low cost.

In addition to the above-described effects, specific effects of the present invention are described below while explaining specific details for carrying out the invention.

Figure 1 is a cross-sectional view of a reflective anti-counterfeiting film according to an embodiment of the present invention.
Figure 2 is a cross-sectional view for explaining the phase difference of light reflected in the diffraction pattern 122 of the diffractive optical element (hereinafter referred to as optical diffraction element or DOE) included in the reflective anti-counterfeiting film.
Figure 3 is a photograph (a) of a conventional hologram and a photograph (b) of a reflective anti-counterfeiting film having a diffractive optical element of the present invention.
Figure 4 shows a wafer manufacturing process for manufacturing a diffractive optical element, which is part of the method for manufacturing the reflective anti-counterfeiting film of the present invention.
Figure 5 shows steps for converting an original image into a DOE mask.
Figure 6 shows the steps of separating and designing the DOE mask into a plurality of unit masks.
Figure 7 shows an example of arranging each unit mask of the DOE mask on a reticle.
Figure 8 shows exposure steps on a silicon substrate.
Figure 9 shows the etching steps.
Figure 10 shows an example in which a DOE pattern substrate is manufactured.
Figure 11 shows a flow chart of the imprinting process.
Figure 12 shows an example of an anti-counterfeiting film, which is a final product manufactured through the imprinting process.
Figure 13 shows the results of simulating light efficiency according to the number of steps of the DOE unit mask.
Figure 14 shows the results of simulating the light efficiency according to the minimum gap (△h) in the thickness direction between each layer of the diffraction pattern.
Figure 15 shows the image (image) of reflected light according to the level of the DOE unit mask.
Figure 16 shows an image implemented when using two DOE unit masks and an image of a diffraction slit.
Figure 17 shows an image implemented when using three DOE unit masks and an image of a diffraction slit.
Figure 18 shows an image implemented when using five DOE unit masks and an image of a diffraction slit.

Hereinafter, with reference to the drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. The present invention may be implemented in many different forms and is not limited to the embodiments described herein.

In order to clearly explain the present invention, parts that are not relevant to the description are omitted, and identical or similar components are given the same reference numerals throughout the specification. Additionally, some embodiments of the present invention will be described in detail with reference to the exemplary drawings. In adding reference numerals to components in each drawing, identical components may have the same reference numerals as much as possible even if they are shown in different drawings. In the attached drawings, the sizes and amounts of objects are enlarged or reduced from the actual size to ensure clarity of the present invention. Additionally, when describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description may be omitted.

In describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish the component from other components, and the nature, sequence, order, or number of the components are not limited by the term. When a component is described as being “connected,” “coupled,” or “connected” to another component, that component may be directly connected or connected to that other component, but there are no other components between each component. It should be understood that may be “interposed” or that each component may be “connected,” “combined,” or “connected” through other components.

The terms used in this application are only used to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as “comprise” or “comprise” are intended to designate the presence of features, steps, functions, components, or a combination thereof described in the specification, but are not intended to indicate the presence of other features, steps, functions, or components. It should be understood that the existence or addition possibility of combinations thereof is not excluded in advance.

Meanwhile, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and unless explicitly defined in the present application, should not be interpreted in an ideal or excessively formal sense. No.

The present invention seeks to invent a reflective anti-counterfeiting film having a diffraction pattern that can satisfy both the luminous efficiency and productivity that are difficult to coexist with.

Figure 1 is a cross-sectional view of a reflective anti-counterfeiting film according to an embodiment of the present invention.

Referring to FIG. 1, the reflective anti-counterfeiting film 100 according to an embodiment of the present invention includes a base 110 and a diffractive optical element layer 120.

The reflective anti-counterfeiting film 100 reflects most of the visible light, LED light, or laser light incident from the outside from the diffractive optical element layer 120 of the anti-counterfeiting film 100, and some of it is transmitted.

As a result, the upper part of the base 110 can be implemented as a specific image.

In particular, the reflective anti-counterfeiting film 100 has the advantage of less light loss compared to the transmissive or semi-transmissive anti-counterfeiting film.

In the case of a transmissive or semi-transmissive anti-counterfeiting film, the transmitted light passing through the diffractive optical element layer suffers light loss due to the base film or other laminated films.

At this time, a specific image may correspond to an image for determining authenticity. For example, the specific image may include the trademark or log of the manufacturer of the product (object) for which authenticity is to be determined.

As a non-limiting and specific example, the base 110 may be made of a polymer material.

For example, the base 110 may be made of PET material, but is not limited thereto.

As a non-limiting and specific example, synthetic resins such as PP, OPP, and PVC can also be used as the base 110.

Furthermore, paper such as paper or clothing such as cloth can also be used as the base 100.

Additionally, as a non-limiting example, an adhesive layer, an adhesive layer, or a double-sided adhesive tape (not shown) may be placed on the lower surface of the base 110.

The adhesive layer, adhesive layer, or adhesive tape may perform the function of attaching the base 110 to a specific product such as packaging paper.

A diffractive optical element layer 120 may be located on the upper surface of the base 110 (for example, in the case of packaging paper, the outer surface of the packaging paper).

The diffractive optical element layer 120 includes a diffraction pattern 122 on its upper surface. The diffraction pattern 122 may have various sizes and shapes. For example, the shape of the diffraction pattern 122 may include a stripe shape, a mosaic shape, a pyramid shape, etc. The diffraction pattern 122 may be defined as a pattern for using diffraction characteristics to implement a specific image through a design algorithm including Fourier transform and inverse Fourier transform processes.

The diffraction pattern 122 formed on the diffractive optical element layer 120 has a profile in the height (or thickness relative to the packaging) direction.

The diffraction pattern 122 can implement a specific image based on the profile.

Figure 2 is a cross-sectional view for explaining the phase difference of light reflected in the diffraction pattern 122 of the diffractive optical element layer 120 included in the reflective anti-counterfeiting film.

In general, when visible light (not a single wavelength) or light of a single wavelength such as a laser, which travels in a straight line, is incident light and is reflected after being incident on a structure having a profile in the height direction as shown in FIG. 2, the reflected light has the profile A path difference of light occurs as much as the height difference (h') within the light, and the path difference again generates a phase difference of the reflected light.

At this time, the phase difference causes constructive interference or destructive interference of reflected light, forming an image.

Therefore, when the diffraction pattern 122 is designed to finally obtain the desired image, the diffraction pattern 122 reflects incident light such as natural light or light of a single wavelength to create reflected light with the desired image. You can.

At this time, the quality of reflected light having the desired image is determined by the luminous efficiency of the reflected light.

Similar to other general efficiencies, the optical efficiency can be defined as the ratio of the intensity of the reflected light of the remaining diffraction pattern image excluding the light source point to the intensity of the incident light.

Equation 1 below expresses the light efficiency in the reflective diffraction pattern 122 as a formula.

[Equation 1]

(For a more detailed explanation of Equation 1, see "Calculation of diffraction efficiency in hologram gratings attenuated along the direction perpendicular to the grating vector", J. of the optical society of America, pp. 280-287 vol. 63 No. 3, March (see 1973)

Figure 3 is a photograph (a) of a conventional hologram and a photograph (b) of a reflective anti-counterfeiting film having a diffractive optical element of the present invention.

It can be seen that, unlike conventional holograms, the reflective anti-counterfeiting film of the present invention has a profile in the height direction.

At this time, the reflective anti-counterfeiting film of the present invention includes a diffraction pattern 122 constituting the profile, and the diffraction pattern 122 includes a plurality of layers having different heights.

Each layer of the plurality of layers constituting the diffraction pattern 122 has a thickness (h) lower than the total thickness (H) of the diffractive optical element, and the difference between the thicknesses (h) of each layer is constitutes the profile.

Meanwhile, the diffractive optical element may include a residue 121 on the lower surface of the diffraction pattern due to characteristics such as an imprinting process, which will be described later. The residue 121 refers to the lower part of the film on which a pattern is not formed by imprinting when an anti-counterfeiting film is manufactured using an imprinting process.

The thickness of the residue 121 is optimized depending on process conditions, etc. Even though the residue 121 does not directly affect the optical characteristics of the diffractive optical element, the residue 121 may indirectly affect the optical characteristics of the diffractive optical element.

For example, if the diffractive optical element is attached to a surface with a rough surface, the resin 121 functions like a mirror due to the characteristics of the material of the resin 121. It can be done. Therefore, part of the incident light incident on the uneven material is reflected due to the mirror effect of the residue 121 and enters the diffractive optical element, thereby contributing to a certain extent to improve the intensity of the finally observed diffraction light.

However, since the residue 121 does not directly affect the optical characteristics of the diffractive optical element, the total thickness (H) of the diffractive optical element described hereinafter and each layer constituting the diffraction pattern 122 The thickness (h) of does not include the thickness of the residue 121. In other words, the total thickness (H) of the diffractive optical element 120 and the thickness (h) of each layer constituting the diffraction pattern 122 described in this specification all refer to the thickness excluding the thickness of the residue 121. do.

At this time, the total thickness (H) of the diffractive optical element in the reflective anti-counterfeiting film of the present invention may be 200 to 330 nm.

If the thickness H is thinner than 200 nm, the mechanical stability of the diffractive optical element becomes weak, and furthermore, the too thin thickness makes it difficult to implement the diffraction pattern 122 during imprinting after the semiconductor process.

On the other hand, if the thickness (H) is thicker than 330 nm, there is a problem that the light efficiency is reduced because more incident light is absorbed by the diffractive optical element itself.

Meanwhile, as shown in FIG. 2, in order for reflected light to form an image, the diffractive optical element must have the above profile.

Additionally, in order to form the profile as described above, there must be a minimum spacing (Δh) in the thickness direction between each layer of the diffraction pattern.

At this time, the minimum gap (△h) in the thickness direction between each layer of the diffraction pattern may be 6 to 135 nm.

If the minimum gap (Δh) is thinner than 6 nm, there is a problem in that it becomes difficult to implement the diffraction pattern 122 during imprinting after the semiconductor process.

On the other hand, if the minimum gap (△h) is thicker than 135 nm, there is a problem that the incident light absorbed by the diffractive optical element itself increases and the diffraction of the reflected light is not sufficient, resulting in a decrease in light efficiency.

The minimum spacing (Δh) is preferably 12 to 80 nm.

It is more preferable that the minimum gap (Δh) is 20 to 50 nm.

In particular, the minimum gap (Δh) in the thickness direction between each layer of the diffraction pattern directly affects the light efficiency and productivity (yield).

In general, as the minimum gap (△h) in the thickness direction between each layer of the diffraction pattern becomes smaller, the light efficiency increases and the reflected light image becomes finer and clearer.

In contrast, the minimum spacing (△h) in the thickness direction between each layer in the diffraction pattern that is actually implemented by a process such as imprinting is not only more difficult to implement as the minimum spacing (△h) becomes smaller, but also increases productivity. This becomes deteriorated.

Ultimately, luminous efficiency and productivity have a trade-off relationship depending on the change in the minimum gap (Δh) in the thickness direction between each layer of the diffraction pattern.

In other words, the luminous efficiency and productivity have a characteristic relationship that makes it difficult for them to coexist.

Meanwhile, the reflective anti-counterfeiting film of the present invention may further include a light reflection layer, an adhesive layer, an adhesive layer, and a protective layer in addition to the base and the diffractive optical element layer.

Figure 4 shows a wafer manufacturing process for manufacturing a diffractive optical element, which is part of the method for manufacturing the reflective anti-counterfeiting film of the present invention.

5 to 10 illustrate each step of the wafer manufacturing process.

First, as shown in FIG. 4, the method of manufacturing the reflective anti-counterfeiting film of the present invention includes the steps of (a) converting the original image image into a DOE (diffraction optical elements) mask; (b) separating the DOE mask into a plurality of DOE unit masks; (c) manufacturing each layer of the DOE unit mask; (d) exposing the substrate; (e) etching; (f) manufacturing a DOE pattern substrate.

Figure 5 shows steps for converting an original image into a DOE mask.

First, the original image to be displayed by the diffractive optical element is simulated through Fourier transformation to determine whether the target efficiency and intensity are obtained from an actual light source (natural light or laser light). As a non-limiting and specific example of the light source, the light source may be short-wavelength green light. In particular, green light is desirable because not only is it the most visible to the human eye among natural lights, but the intensity of the light is greater than that of other wavelengths.

The simulation process may be omitted as needed.

Next, after setting the target intensity of the original image, a DOE mask is designed through inverse Fourier transformation to obtain a DOE mask to implement it.

Figure 6 shows the steps of separating and designing the DOE mask into a plurality of unit masks.

The DOE mask may be designed as a single mask or as a plurality of unit masks.

If a single DOE mask is designed, the diffraction pattern 122 in the diffractive optical element included in the anti-counterfeiting film, which is the final product, cannot accurately express the final image (see level 2 in FIG. 13).

On the other hand, if the DOE mask is designed with an excessively large number (steps), the improvement in light efficiency or the clarity perceived by the observer cannot be achieved, and the diffraction pattern 122 included in the final product, the anti-counterfeiting film, becomes too precise and complicated, resulting in productivity loss. Not only does it deteriorate, but it also causes problems with yield.

Figure 7 shows an example of arranging each unit mask of the DOE mask on a reticle.

Figure 8 shows exposure steps on a silicon substrate.

Figure 9 shows etching steps.

As shown in FIGS. 7 to 9, the plurality of unit masks implement a diffraction pattern 122 on a silicon wafer through conventional photo lithography.

Specifically, a diffraction pattern 122 can be formed on the wafer on which the photoresist is applied by exposing a light source (UV or EUV light source) on the reticle original plate.

More specifically, as shown in FIG. 9, when the photolithography process is performed multiple times using each unit mask, a diffraction pattern 122 including layers having different thicknesses is formed in the final wafer.

Figure 10 shows an example in which a DOE pattern substrate is manufactured.

As shown in FIG. 10, a diffraction pattern 122 including layers having different thicknesses as shown in the schematic diagram is formed on the silicon wafer manufactured by the DOE mask by the etching step in FIG. 9. can be seen.

Meanwhile, single or multiple identical master stamps having the same diffraction pattern 122 can be formed on one silicon substrate by the above method.

Hereinafter, as a non-limiting and specific example, a method of manufacturing an anti-counterfeiting film through an imprinting process using the master stamp will be described in more detail.

Figure 11 shows a flow chart of the imprinting process.

Figure 12 shows an example of an anti-counterfeiting film, which is a final product manufactured through the imprinting process.

First, a fabric tiling process may be performed using a single or multiple master stamps located on the wafer.

The tiling process is a process for manufacturing a copper plate that can be used to imprint the diffraction pattern 122 of a diffractive optical element on an anti-counterfeiting film using a replica.

Specifically, in the tiling process, the master stamp is copied on a tiling film by machine or manually, and then tiled to match the size of the anti-counterfeiting film. As a non-limiting and specific example, the tiling may be carried out to a size of about 1,200 mm in width, but can be adjusted depending on the size of the final product and/or copper plate, etc.

The tiled exclusive film is used to manufacture a roll-type master mold used in the subsequent molding process, and the master mold is implanted on a copper plate.

The copper plate manufactured through the tiling process can be implanted with a diffractive optical element into an anti-counterfeiting film through a subsequent molding process.

As a non-limiting and specific example, the forming process may be a roll to roll process or a roll to plate process.

The diffractive optical element manufactured through the molding process and located within the anti-counterfeiting film is located on the base as shown in FIGS. 1 and 12.

Therefore, in order to manufacture the diffractive optical element, a base and a laminate of resin positioned on the base and from which the diffractive optical element can be formed must proceed before the molding process.

At this time, the base is preferably a highly transparent film that can transmit light. PET, etc. can be used as a non-limiting and specific example. In particular, PET has higher mechanical rigidity compared to other olefin polymers, so it is suitable as a base.

The diffractive optical element located on the base may be made of polymer resin.

At this time, the polymer resin may be urethane-based or acrylic-based.

At this time, the polymer resin can be cured through heat curing or UV curing.

The laminate of the base and the resin is provided to the master mold in a roll type through a supply roller, and the master mold is applied to the laminate to be worked while applying a certain force to the laminate similar to rolling during the forming process. The opposite pattern can be engraved. Through this, a diffraction pattern 122 constituting a diffractive optical element can be formed in the laminate.

Furthermore, the lower and/or upper part of the base may include a printed layer with a trademark printed on it, if necessary, to increase product identification.

Additionally, an adhesive layer and/or an adhesive layer and/or a double-sided tape may be laminated so that the anti-counterfeiting film can be adhered to the packaging that protects the product.

The reflective anti-counterfeiting film of the present invention and its manufacturing method will be described through examples below.

Example

Figure 13 shows the results of simulating light efficiency according to the number of steps of the DOE unit mask.

Figure 14 shows the results of simulating the light efficiency according to the minimum gap (△h) in the thickness direction between each layer of the diffraction pattern.

The luminous efficiency is a result of simulation using Luen Soft's Virtual Lab Fusion (2nd Generation Technology Update) program based on Equation 1 above.

First, as shown in FIG. 13, it can be seen that light efficiency increases as the level of the DOE mask implementing the diffraction pattern increases.

At this time, as the DOE mask level increases from 1 to 3, the light efficiency increases rapidly.

On the other hand, as the DOE mask level increased from 3 to 6, the light efficiency showed little change or a slight increase.

The results in FIG. 13 mean that the light efficiency is almost saturated when the DOE mask level is 3 or 4.

Meanwhile, as shown in FIG. 14, it can be seen that the light efficiency increases as the minimum gap (△h) in the thickness direction between each layer of the diffraction pattern becomes thinner.

At this time, the light efficiency was found to be almost constant or slightly decreased until the minimum gap (△h) in the thickness direction between each layer of the diffraction pattern was approximately 20 nm.

On the other hand, when the minimum gap (△h) in the thickness direction between each layer of the diffraction pattern exceeds approximately 50 nm, the light efficiency was found to decrease significantly.

The results of FIGS. 13 and 14 mean that the light efficiency does not simply change linearly with respect to the minimum spacing (Δh) in the thickness direction between each layer of the diffraction pattern.

In particular, when the minimum distance (△h) in the thickness direction between each layer of the diffraction pattern is 20 to 50 nm, it means that a diffraction pattern with excellent productivity can be obtained without changing light efficiency.

Figure 15 shows the image (image) of reflected light according to the level of the DOE unit mask.

Figure 15 intuitively shows the image of reflected light that an observer actually observes.

As shown in FIG. 15, as the layers constituting the diffraction pattern increase with respect to the total height (H) of the diffraction pattern (in other words, the minimum spacing (△h) in the thickness direction between each layer of the diffraction pattern increases. (As this decreases), it can be seen that the image of reflected light becomes clearer.

Looking more specifically, it can be seen that as the layers constituting the diffraction pattern increase from 2 levels to 8 levels, the clarity of the reflected light rapidly improves, but there is little change thereafter until level 32.

The results of Figure 15 agree very well with the results of Figures 13 and 14 above.

Meanwhile, it can be seen that when the incident light is green light, the image of the reflected light is clearer than when the incident light is white light. This is because in the case of white light, various wavelengths are mixed rather than a single wavelength, which causes the lights of various wavelengths to interfere with each other.

Figures 16 to 18 show examples of actually implemented images and diffraction slits according to the number of DOE unit masks.

As shown in FIG. 16, when an image is implemented using two DOE unit masks (in the case of diffraction patterns 122 with four different heights), the desired lightning image and the actually implemented image are not the same. can be seen.

On the other hand, as shown in FIGS. 17 and 18, there are three DOE unit masks (FIG. 17, diffraction patterns 122 with 8 different heights) and 5 (FIG. 18, diffraction patterns 122 with 32 different heights). When implementing an image using )), it can be confirmed that the desired lightning image is actually implemented, and furthermore, it can be confirmed that the diffraction slits are so similar that the difference is difficult to clearly distinguish with the naked eye.

The results of FIGS. 16 to 18 can be said to intuitively (visually) verify the results of FIG. 15 described above.

As described above, the present invention has been described with reference to the illustrative drawings, but the present invention is not limited to the embodiments and drawings disclosed herein, and various modifications may be made by those skilled in the art within the scope of the technical idea of the present invention. It is obvious that transformation can occur. In addition, although the operational effects according to the configuration of the present invention were not explicitly described and explained while explaining the embodiments of the present invention above, it is natural that the predictable effects due to the configuration should also be recognized.

Claims (10)

Base;
It includes a diffractive optical element layer located on the base and including a diffraction pattern,
The diffraction pattern 122 includes a plurality of layers,
The minimum gap (△h) in the thickness direction between the plurality of layers is 20 to 50 nm,
A reflective anti-counterfeiting film wherein the total height (H) of the diffraction pattern is 200 to 330 nm.
delete According to claim 1,
A reflective anti-counterfeiting film comprising a residue positioned between the diffraction pattern and the base.
According to claim 1,
The base is a reflective anti-counterfeiting film made of transparent PET.
According to claim 1,
The diffractive optical element layer is a reflective anti-counterfeiting film made of urethane-based or acrylic-based resin.
According to claim 1,
A reflective anti-counterfeiting film further comprising an adhesive layer, an adhesive layer, or a double-sided tape located on the lower part of the base.
According to claim 1,
A reflective anti-counterfeiting film further comprising a printing layer located on the top and/or bottom of the base.
(a) converting the original image image into a DOE (diffraction optical elements) mask through Fourier transform and inverse Fourier transform;
(b) separating the DOE mask into three DOE unit masks;
(c) manufacturing each of the three DOE unit masks;
(d) manufacturing a master stamp including a diffraction pattern on a silicon substrate by sequentially exposing and etching each of the DOE unit masks;
(e) imprinting a diffractive optical element using the master stamp. A reflective anti-counterfeiting film manufacturing method comprising a.
In a reflective diffractive optical element including a diffraction pattern,
The diffraction pattern includes a plurality of layers,
The minimum gap (△h) in the thickness direction between the plurality of layers is 20 to 50 nm,
A reflective diffractive optical device wherein the total height (H) of the diffraction pattern is 200 to 330 nm. delete

Images