KR102377297B1 - Transmissive type diffraction optical elements and manufacturing method for the same - Google Patents

Abstract

The present invention relates to a transmission type diffractive optical element in which a diffraction pattern includes a plurality of layers, and a minimum spacing (△h) in the thickness direction between the plurality of layers is 110 to 160 nm, and a method of manufacturing the same.

Description

Transmissive diffractive optical element and method of manufacturing the same {TRANSMISSIVE TYPE DIFFRACTION OPTICAL ELEMENTS AND MANUFACTURING METHOD FOR THE SAME}

The present invention relates to a transmission type diffractive optical element and a method of manufacturing the same.

Holograms and diffractive optical elements have been used in the fields of anti-counterfeiting technology and depth measurement technology.

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 diffractive optical element using a semiconductor process, especially a micropattern process, has been developed.

Diffractive optical elements can generally be classified into transmission-type diffractive optical elements, semi-transmissive diffractive optical elements, transmission-type diffractive optical elements, etc.

Among these, transmission-type diffractive optical elements have recently been increasingly used in wearable smart glasses and AR/VR.

In particular, transmission-type diffractive optical elements can be applied to technologies that provide necessary information or images to users by irradiating light to the glass surfaces or helmets of transportation vehicles such as cars or airplanes.

Since the diffractive optical element 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 diffractive optical element or the film itself including the diffractive optical element.

As a result, for example, a problem arises where the manufacturing cost of the diffractive optical element itself exceeds the price of the product to which the diffractive optical element is attached.

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

In particular, unlike conventional holograms or reflective diffractive optical devices, transmission-type diffractive optical devices provide images or information on the back of a base or substrate, so light absorption by the base or substrate inevitably occurs.

Ultimately, transmission-type diffractive optical elements are more likely to have reduced optical efficiency compared to holograms or other diffractive optical elements, so the need to minimize the reduction in optical efficiency is even higher.

The present invention is an invention to solve the problems of the conventional transmission-type diffractive optical elements described above, and its purpose is to provide a transmission-type diffractive optical element with excellent productivity while securing maximum light efficiency and a method of manufacturing the same.

Another object of the present invention is to provide a transmission type diffractive optical element 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 a transmission-type diffractive optical element and a method of manufacturing the same that can implement information with complex images brighter and clearer.

A transmissive 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 as being 110 to 160 nm.

At this time, the total height (H) of the diffraction pattern is preferably 800 to 1100 nm.

In order to achieve the above object, a film including a transmission-type diffractive optical element layer according to an embodiment of the present invention includes a base; A transmission type 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 It is characterized in that it is 110 to 160 nm.

At this time, the total height (H) of the diffraction pattern is preferably 800 to 1100 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 a transmission-type diffractive optical element 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 layers; (c) manufacturing each of the three layers of DOE masks; (d) manufacturing a master stamp including a diffraction pattern on the silicon substrate by sequentially exposing and etching each of the DOE masks.

To achieve the above object, a film manufacturing method including a transmission-type diffractive optical element layer according to an embodiment of the present invention includes (a) converting the original image image into a DOE (diffraction optical elements) mask. step; (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.

According to the present invention, it is possible to provide a transmission-type diffractive optical element that has excellent light efficiency characteristics, provides clear information, and has high productivity, and a method of manufacturing the same.

Specifically, the transmissive diffractive optical element according to the present invention can provide a transmissive diffractive optical element that can provide clear information with high light efficiency.

In addition, according to the manufacturing method of a transmission-type diffractive optical element according to the present invention, a transmission-type diffractive optical element with excellent both productivity and light efficiency characteristics can be manufactured at a 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.

1 is a cross-sectional view of a film including a transmissive diffractive optical element according to an embodiment of the present invention.
Figure 2 is a cross-sectional view for explaining the phase difference of light transmitted through the diffraction pattern of a transmission type diffractive optical element (hereinafter referred to as an optical diffraction element or DOE).
Figure 3 is a photograph taken of a conventional hologram (a) and a photograph taken of a transmission-type diffractive optical element of the present invention (b).
Figure 4 shows a wafer fabrication process that is part of the method for manufacturing the transmission-type diffractive optical element 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 a final product film containing a transmissive diffractive optical element 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 transmitted 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 film including a transmissive diffractive optical element and a transmissive diffractive optical element having a diffraction pattern that can satisfy both the optical efficiency and productivity that are difficult to coexist with.

1 is a cross-sectional view of a film including a transmissive diffractive optical element according to an embodiment of the present invention.

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

Visible light, LED light, or laser light incident from the outside is mostly transmitted from the diffractive optical element layer 120 of the film 100 including the transmission type diffractive optical element, and only a small portion is reflected.

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

In particular, the film 100 including a transmissive diffractive optical element may have a greater loss of light compared to a film containing a reflective or transflective diffractive optical element, so the design of the transmissive diffractive optical element is very important.

In the case of a film containing a transmission-type diffractive optical element, light loss occurs in the transmitted light passing through the diffractive optical element layer due to the base film or other laminated films.

At this time, the specific image may correspond to an image for determining authenticity or an image to be provided to the user. For example, the image may include the trademark or logo of the manufacturer of the product (object) requiring authenticity determination, or information to be provided to the user.

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.

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 transmission type 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 transmission-type 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 film) 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 transmitted through the diffraction pattern 122 of the transmission-type diffractive optical element layer 120 included in the film containing the transmission-type diffractive optical element.

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 on a structure having a profile in the height direction as shown in Figure 2 and then transmitted, the transmitted 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 transmitted light.

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

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

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

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

Equation 1 below expresses the luminous efficiency in a transmission-type diffractive optical element 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) taken of a conventional hologram and a photograph (b) taken of a film including a transmission-type diffractive optical element of the present invention.

It can be seen that, unlike conventional holograms, the film containing the transmission-type diffractive optical element of the present invention has a profile in the height direction.

At this time, the film containing the transmission-type diffractive optical element 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 transmission type diffractive optical element, and the thickness (h) of each layer is The differences constitute the profile.

Meanwhile, the transmission-type 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 portion of the film on which a pattern is not formed by imprinting when a film including a transmission-type diffractive optical element 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 transmission-type diffractive optical element, the residue 121 may indirectly affect the optical characteristics of the transmission-type diffractive optical element.

For example, if the transmission-type 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. can be performed. 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 negatively contributing to an extent to improving the intensity of the finally observed diffraction light.

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

At this time, in the film including the transmission-type diffractive optical element of the present invention, the total thickness (H) of the transmission-type diffractive optical element may be 880 to 1,100 nm.

If the thickness (H) is thinner than 880 nm, the mechanical stability of the transmissive diffractive optical element becomes weak, and furthermore, due to the too thin thickness, some light is reflected and becomes transflective rather than transmissive, or there is a problem of low optical efficiency. .

On the other hand, if the thickness (H) is thicker than 1,100 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 transmitted light to form an image (image), the transmission type 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 (Δh) in the thickness direction between each layer of the diffraction pattern may be 28 to 550 nm.

If the minimum gap (Δh) is thinner than 28 nm, the number of semiconductor processing steps to manufacture the master stamp increases, leading to a problem of reduced productivity.

On the other hand, if the minimum gap (Δh) is thicker than 550 nm, there is a problem that light efficiency is reduced due to insufficient diffraction of transmitted light.

The minimum spacing (Δh) is preferably 55 to 275 nm.

It is more preferable that the minimum spacing (Δh) is 110 to 160 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 transmitted 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 film including the transmission-type diffractive optical element of the present invention may further include a light transmission layer, an adhesive layer, an adhesive layer, and a protective layer in addition to the base and the diffractive optical element layer.

4 shows a wafer fabrication process for manufacturing a transmission-type diffractive optical element, which is part of a method of manufacturing a film containing a transmission-type diffractive optical element 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 a film including a transmission-type diffractive optical element of the present invention includes (a) converting the original image image into a DOE (diffraction optical elements) mask; (b) separating the DOE mask into a plurality of 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 transmissive diffractive optical element is simulated to determine whether the target efficiency and intensity are obtained by an actual light source (natural light or laser light) through Fourier transform. 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 transmissive diffractive optical element included in the film containing the transmissive diffractive optical element, which is the final product, cannot accurately express the final image (2 in Figure 13). (see level)

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 final product, the transmission-type diffractive optical element, or the film containing the transmission-type diffractive optical element The diffraction pattern 122 becomes too precise and complex, which not only reduces productivity but 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 the 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 a film including a transmission-type diffractive optical element 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 a film containing a transmission-type diffractive optical element, which is one of the final products 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 a film containing a transmission-type diffractive optical element using a replica.

Specifically, in the tiling process, the master stamp is copied on a tiling-only film by machine or manually, and then tiled to fit the size of the film including the transmissive diffractive optical element. As a non-limiting and specific example, the tiling may be performed at a size of approximately 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 by the tiling process can be implanted with a transmission-type diffractive optical element into a film containing a transmission-type diffractive optical element 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 transmission-type diffractive optical element manufactured through the molding process and located within the film containing the transmission-type diffractive optical element is located on a base as shown in FIGS. 1 and 12.

Therefore, in order to manufacture the transmission-type diffractive optical element, a base and a laminate of resin positioned on the base and capable of forming the transmission-type diffractive optical element must be performed before the molding process.

At this time, since the diffractive optical element of the present invention is a transmission type, the base is preferably a film with high transparency that can transmit light.

PET, etc. may be used as a non-limiting and specific example.

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

However, in the case of PET, it is suitable for the base because it not only has high transparency but also has higher mechanical rigidity compared to other olefin polymers.

The transmission-type 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 during the molding process, a constant force is applied to the laminate similar to rolling and the master mold is applied to the laminate to be worked. The opposite pattern can be engraved. Through this, a diffraction pattern 122 constituting a transmission-type 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 film including the transmission-type diffractive optical element can be adhered to the component to which the transmission-type optical element is attached.

The film including the transmission-type diffractive optical element 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.

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.

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In particular, when the minimum distance (△h) in the thickness direction between each layer of the diffraction pattern is 110 to 160 nm, it means that a diffraction pattern with excellent productivity can be obtained without changing light efficiency.

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

Figure 15 intuitively shows the image of transmitted 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 transmitted 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 transmitted light rapidly improves, but there is almost no change thereafter until the 32nd level.

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 transmitted 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 in the above description of the embodiments of the present invention, it is natural that the predictable effects due to the configuration should also be recognized.

Claims (11)

In a transmission-type 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 110 to 160 nm,
A transmission type diffractive optical device wherein the total height (H) of the diffraction pattern is 880 to 1100 nm.
delete Base;
It includes a transmission type diffractive optical element layer located on the base and including a diffraction pattern,
The diffraction pattern includes a plurality of layers, and the minimum spacing (△h) in the thickness direction between the plurality of layers is 110 to 160 nm,
A film comprising a transmission-type diffractive optical element layer, characterized in that the total height (H) of the diffraction pattern is 880 to 1100 nm.
delete According to claim 3,
A film comprising a transmission-type diffractive optical element layer including a residue positioned between the diffraction pattern and the base.
According to claim 3,
The base is a film comprising a transparent diffractive optical element layer of transparent PET.
According to claim 3,
The diffractive optical element layer is a film comprising a transmission-type diffractive optical element layer made of urethane-based or acrylic-based resin.
According to claim 3,
A film comprising a transmission-type diffractive optical element layer further comprising an adhesive layer, an adhesive layer, or a double-sided tape positioned below the base.
According to claim 3,
A film comprising a transmission-type diffractive optical element layer further comprising a printing layer located on top and/or below 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.
(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 film manufacturing method comprising a transmission-type diffractive optical element layer.

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