WO2023003125A1 - Transmissive diffractive optical device, film comprising same, and method for manufacturing film - Google Patents

Abstract

The present invention relates to a transmissive diffractive optical device comprising a diffraction pattern, wherein the diffraction pattern comprises a plurality of layers, the minimum spacing (Δh) in the thickness direction between the plurality of layers is 45 nm to 200 nm, and the total height (H) of the diffraction pattern is 800 nm to 1350 nm, and relates to a film comprising the transmissive diffractive optical device, and a method for manufacturing the film.

Description

Transmissive diffractive optical element, film including the same, and manufacturing method thereof

The present invention relates to a transmissive diffractive optical element capable of implementing an image using a pattern, and a method for manufacturing a film including the same.

A hologram or a diffractive optical element has been used in the forgery prevention technology field or the depth measurement technology field.

A hologram is a medium on which interference fringes that reproduce a three-dimensional image are recorded, and is manufactured using the principle of holography.

More specifically, the hologram reproduces (or implements) a specific image by incident (or irradiated) reproduction light having the same frequency, wavelength, and phase as the reference light at a specific angle to the interference fringe.

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

Furthermore, there is a limit to the information that can be recorded as a hologram, so it is difficult to produce a sophisticated hologram.

Furthermore, since holograms are usually located only in a part of a product or part of a product package due to difficulties in manufacturing, there is a problem in that they can be easily removed.

In order to improve the problems of the hologram, a diffractive optical element using a semiconductor process, particularly a fine pattern process, has been developed.

Diffractive optical elements can generally be classified into transmissive diffractive optical elements, transflective diffractive optical elements, transmissive diffractive optical elements, and the like.

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

In particular, the transmissive diffractive optical element may be applied to a technology for providing necessary information or images to provide information to a user by irradiating light onto a glass surface or a helmet of a means of transportation such as a car or an airplane.

Since the diffractive optical element uses a semiconductor process, productivity decreases as the fine pattern process increases.

More specifically, when the fine pattern process increases, sharper and brighter information can be recorded, but low productivity rapidly 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 that 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 is reduced, the clarity of recorded information is lowered and the light conversion efficiency is reduced.

In particular, unlike conventional holograms or reflective diffractive optical elements, the transmissive diffractive optical element provides images or information on the back side of a base or substrate, so that light absorption by the base or substrate inevitably occurs.

As a result, since the transmissive diffractive optical element is likely to have lower light conversion efficiency compared to holograms or other diffractive optical elements, the need to minimize the decrease in light conversion efficiency is further increased.

The present invention is an invention to solve the problems of the conventional transmissive diffractive optical element described above, and a transmissive diffractive optical element (hereinafter referred to as diffraction optical elements or DOE) with excellent productivity while securing maximum light conversion efficiency and manufacturing the same It aims to provide a method.

Another object of the present invention is to provide a transmissive diffractive optical element in which the height of an information pattern portion in which information is stored is controlled, and a manufacturing method thereof.

Another object of the present invention is to provide a transmissive diffractive optical element and a method for manufacturing the same, which can implement information having a complex image more brightly and clearly.

Furthermore, an object of the present invention is to provide a transmissive diffractive optical element capable of having maximum light conversion efficiency even for input light having various wavelengths by using characteristics of white light in which various wavelengths are mixed, and a manufacturing method thereof.

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 a minimum distance between the plurality of layers in a thickness direction. (Δh) may be 45 to 200 nm, and the total height (H) of the diffraction pattern may be a transmissive diffractive optical element having a range of 800 to 1350 nm.

At this time, in the transmissive diffractive optical element, the minimum distance (Δh) in the thickness direction between the plurality of layers is 60 to 200 nm, and the light conversion efficiency of the diffractive optical element is calculated by Equation 1 below. It may be a transmissive diffractive optical element having a value of 63% or more.

(Equation 1)

(In Equation 1 above, {U _sig (x')} ² means the Intensity of the Desired Output Field, and {U _in (ξ)} ² below means the Intensity of the Input Field, and the alpha value is As a scaling factor, it corresponds to a kind of correction value to reduce the error between the desired result area (Desired Output Field) and the calculated intensity of the output field. means the position value in the input field, and W _sig means the Optimization Region.)

At this time, in the transmissive diffractive optical element, the minimum distance (Δh) in the thickness direction between the plurality of layers is 50 to 195 nm, and the light conversion efficiency of the diffractive optical element is calculated by Equation 1 above. It may be a transmissive diffractive optical element having a value of 55% or more.

At this time, in the transmissive diffractive optical element, the minimum distance (Δh) in the thickness direction between the plurality of layers is 45 to 190 nm, and the light conversion efficiency of the diffractive optical element is calculated by Equation 1 above. It may be a transmission-type diffractive optical element having a value of 51% or more.

A film according to an embodiment of the present invention includes a base; and a transmissive diffractive optical element layer disposed on the base and including a diffraction pattern, wherein the diffraction pattern 122 includes a plurality of layers, and a minimum distance between the plurality of layers in a thickness direction (Δ h) is 45 to 200 nm, and the total height (H) of the diffraction pattern may be a film of 800 to 1350 nm.

At this time, in the film, the minimum distance (Δh) in the thickness direction between the plurality of layers is 60 to 200 nm, and the light conversion efficiency of the diffractive optical element is 63% calculated by Equation 1 above. Ideally, it may be a film.

At this time, in the film, the minimum distance (Δh) in the thickness direction between the plurality of layers is 50 to 195 nm, and the light conversion efficiency of the diffractive optical element is 55% by the value calculated by Equation 1 above. It may be an ideal film.

At this time, in the film, the minimum distance (Δh) in the thickness direction between the plurality of layers is 40 to 190 nm, and the light conversion efficiency of the diffractive optical element is 51% calculated by Equation 1 above. Ideally, it may be a film.

Preferably, the film may include a residue positioned between the diffraction pattern and the base.

Preferably, the base of the film may be transparent PET.

Preferably, the diffractive optical element layer may be a urethane-based or acrylic-based resin.

Preferably, the film may further include an adhesive layer, an adhesive layer, or a double-sided tape positioned below the base.

Preferably, the film may further include a printing layer positioned above and/or below the base.

A manufacturing method of a transmissive diffractive optical element according to an embodiment of the present invention includes: (a) transforming an original image into a diffraction optical elements (DOE) mask through Fourier transform and inverse Fourier transform; (b) separating the DOE mask into 3, 4 or 5 DOE unit masks; (c) manufacturing each of the 3, 4 or 5 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 method of manufacturing a film according to an embodiment of the present invention includes: (a) transforming an original image into a diffraction optical elements (DOE) mask through Fourier transform and inverse Fourier transform; (b) separating the DOE mask into 3, 4 or 5 DOE unit masks; (c) manufacturing each of the 3, 4 or 5 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; may include.

According to the present invention, it is possible to provide a transmissive diffractive optical element having excellent light conversion efficiency characteristics and high productivity while providing clear information and a manufacturing method thereof.

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

More specifically, the transmissive diffractive optical element according to the present invention has an effect of implementing maximum light conversion efficiency for each of red (R), green (G), and blue (B) components of white light (visible light). can

In addition, according to the manufacturing method of the transmissive diffractive optical element according to the present invention, the manufacturing method of the transmissive diffractive optical element excellent in both productivity and light conversion efficiency can be manufactured at a low cost.

In addition to the effects described above, specific effects of the present invention will be described together while explaining specific details for carrying out the present invention.

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

2 is a cross-sectional view for explaining a phase difference of light transmitted through a diffraction pattern of a transmission-type diffractive optical element (Diffractive Optical Element, hereinafter referred to as an optical diffraction element or DOE).

3 is a photograph of a conventional hologram and a photograph of a transmissive diffractive optical element of the present invention.

4 shows a wafer fabrication process, which is part of a method for manufacturing a transmissive diffractive optical element of the present invention.

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

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

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

8 shows a step of exposing on a silicon substrate.

9 shows the etching step.

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

11 shows a flowchart of an imprinting process for manufacturing a DOE from a substrate having a DOE pattern.

12 shows a film as an example of a final product including a transmissive diffractive optical element manufactured through the imprinting process.

13 shows simulation results of the light conversion efficiency according to the number of steps of the DOE unit mask and the red light (R), green light (G), and blue light (B) light sources.

14 shows simulation results of light conversion efficiencies according to the minimum distance (Δh) between each layer of the DOE diffraction pattern in the thickness direction and red light (R), green light (G), and blue light (B) light sources.

FIG. 15 shows images (images) of transmitted light according to the steps of a DOE unit mask when the incident light is red light (R), green light (G), and blue light (B), and white light (W).

16 shows an image implemented when using two DOE unit masks and an image of a diffraction slit.

17 shows an image implemented when using three DOE unit masks and an image of a diffraction slit.

18 shows an image implemented when using 5 DOE unit masks and an image of a diffraction slit.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings so that those skilled in the art can easily carry out the present invention. This invention may be embodied in many different forms and is not limited to the embodiments set forth herein.

In order to clearly describe the present invention, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification. In addition, some embodiments of the present invention are described in detail with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same numerals as much as possible even if they are displayed on different drawings. In the accompanying drawings, the size and quantity of the objects are shown enlarged or reduced than actual for clarity of the present invention. In addition, in 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 corresponding component is not limited by the term. When an element is described as being “connected,” “coupled to,” or “connected” to another element, that element is or may be directly connected to that other element, but intervenes between each element. It will be understood that may be "interposed", or each component may be "connected", "coupled" or "connected" through other components.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as "comprise" or "have" are intended to designate that the features, steps, functions, components, or combinations thereof described in the specification exist, but other features, steps, functions, or components Or it should be understood that the possibility of existence or addition of those in combination is not precluded.

Meanwhile, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in the present application, they should not be interpreted in an ideal or excessively formal meaning. don't

The present invention intends to invent a transmissive diffractive optical element having a diffraction pattern capable of satisfying both the light conversion efficiency and productivity, which are difficult to coexist with each other, and a film including the transmissive diffractive optical element.

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 transmissive diffractive optical element according to an embodiment of the present invention includes a base 110 and a diffractive optical element layer 120 .

The diffractive optical element layer 120 means a layer on which a diffractive pattern 122 forming a diffractive optical element (DOE) is located.

Most of the visible light, LED light, or laser light incident from the outside is transmitted from the diffractive optical element layer 120 of the film 100 including the transmissive diffractive optical element, and only a small part is reflected.

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

In particular, since the film 100 including the transmissive diffractive optical element may have a large loss of light compared to the film including the reflective or semi-transmissive diffractive optical element, the design of the transmissive diffractive optical element is very important.

This is because, in the case of a film including a transmissive diffractive optical element, light loss occurs in the transmitted light passing through the diffractive optical element layer by the base film or other layered films.

In this case, the specific image may correspond to an image for determining authenticity or an image to be provided to a user. For example, the image may include a trademark or logo of a manufacturer of a product (object) for which authenticity determination is required or information to be provided to a 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 may also be used as the base.

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

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

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

The transmissive 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, and the like. The diffraction pattern 122 may be defined as a pattern for using diffraction characteristics to implement a specific image through a design algorithm including a Fourier transform and an inverse Fourier transform process.

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

The diffraction pattern 122 may implement a specific image by the profile.

2 is a cross-sectional view for explaining a phase difference of light transmitted through a diffraction pattern 122 of a transmissive diffractive optical element layer 120 included in a film including a transmissive diffractive optical element.

In general, when visible light (not a single wavelength) having linearity or light of a single wavelength such as a laser is incident light on a structure having a profile in a height direction as shown in FIG. 2 and transmitted, the transmitted light is transmitted through the profile. A path difference of light is generated as much as a height difference (h) within the path, and the path difference again generates a phase difference of transmitted light.

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

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

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

Similar to other general efficiencies, the light conversion efficiency may be defined as a ratio of the intensity of incident light to the intensity of transmitted light of the diffraction pattern image excluding light source points.

Equation 1 below expresses light conversion efficiency in a transmissive diffractive optical element.

(Equation 1)

(In Equation 1 above, {U _sig (x')} ² means the Intensity of the Desired Output Field, and {U _in (ξ)} ² below means the Intensity of the Input Field, and the alpha value is As a scaling factor, it corresponds to a kind of correction value to reduce the error between the desired result area (Desired Output Field) and the calculated intensity of the output field. means the position value in the input field, and W _sig means the Optimization Region.)

3 is a photograph (a) of a conventional hologram and a photograph (b) of a film including a transmissive diffractive optical element (layer) of the present invention.

Unlike conventional holograms, it can be seen that the film including the transmissive diffractive optical element of the present invention has a profile in the height direction.

As shown in FIGS. 1 and 3, the film including the transmissive diffractive optical element of the present invention includes the diffraction pattern 122 constituting the profile. The diffraction pattern 122 includes a plurality of layers (corresponding to the diffraction pattern) 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 transmissive diffractive optical element, and the thickness (h) of each layer is The difference constitutes the profile.

Meanwhile, the transmissive diffractive optical element may include a residue 121 on the lower surface of the diffraction pattern as shown in FIG. 1 due to characteristics of an imprinting process to be described later. The residue 121 refers to a lower portion of a film on which a pattern is not formed by imprinting when a film including a transmissive diffractive optical element is manufactured using an imprinting process.

The thickness of the residue 121 may be optimized according to process conditions. Although the residue 121 does not directly affect the optical characteristics of the transmissive diffractive optical element, the residue 121 may indirectly affect the optical characteristics of the transmissive diffractive optical element.

For example, if the transmissive diffractive optical element is attached to a surface with an uneven surface, the residue 121 functions like a mirror due to the characteristics of the material of the residue 121, which is usually formed of resin. can be performed. Therefore, some of the incident light incident on the rugged material is reflected due to the mirror effect of the residue 121 and incident on the diffractive optical element, thereby contributing negatively to some extent to the intensity improvement of the finally observed diffracted light.

However, since the residue 121 does not directly affect the optical characteristics of the transmissive diffractive optical element, the overall thickness H of the transmissive diffractive optical element and the diffraction pattern 122 described herein below The thickness of the residue 121 is not included in the thickness h of each layer. In other words, the total thickness (H) of the transmissive diffractive optical element layer 120 and the thickness (h) of each layer constituting the diffraction pattern 122, as shown in FIG. 1, are all residue ( 121) means the thickness excluding the thickness. In other words, the total thickness (H, or height) of the diffractive optical element layer 120 is the height from the top of the residue 121 to the top of the diffractive optical element layer 120 based on FIG. it means.

At this time, the total thickness (or height, H) of the transmissive diffractive optical element layer 120 in the film including the transmissive diffractive optical element of the present invention may be 800 to 1,350 nm depending on the color of incident light to be designed. .

If the thickness H is less than 800 nm, the mechanical stability of the transmissive diffractive optical element is weakened, and furthermore, some light is reflected due to the too thin thickness, resulting in a transflective rather than transmissive type or low light conversion efficiency. there is

On the other hand, if the thickness (H) is thicker than 1350 nm, the incident light absorbed by the diffractive optical element itself increases, resulting in a decrease in light conversion efficiency.

Meanwhile, as shown in FIG. 2, in order to form an image (image) of transmitted light, the transmissive diffractive optical element must have the profile.

In addition, as described above, in order to form the profile, a minimum distance Δh in the thickness direction between each layer of the diffraction pattern should be provided.

At this time, the minimum distance (Δh) in the thickness direction between each layer of the diffraction pattern based on white light (also called visible light, including monochromatic red light (R), green light (G), and blue light (B)) Silver is preferably 45 to 200 nm.

If the minimum interval (Δh) is thinner than 45 nm, there is a problem in that productivity is lowered due to the increase in semiconductor process steps for manufacturing the master stamp.

On the other hand, if the minimum interval (Δh) is thicker than 200 nm, there is a problem in that light conversion efficiency is lowered because diffraction of transmitted light is not sufficient.

The minimum interval Δh changes according to the wavelength (ie, color) of the light source when the optical diffractive element is designed. This is because, in the case of R, G, and B constituting visible light, each wavelength is different from each other, and thus the path of each R, G, and B is different from each other. The minimum interval Δh according to each of the R, G, and B light sources will be described in more detail in the following embodiments.

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

In general, as the minimum distance (Δh) between each layer of the diffraction pattern in the thickness direction decreases, the light conversion efficiency increases and the image of the transmitted light becomes finer and clearer.

Unlike this, the minimum distance (Δh) in the thickness direction between each layer in the diffraction pattern actually implemented by a process such as imprinting is not only difficult to implement as the minimum distance (Δh) is small, but also increases productivity accordingly. this will deteriorate

As a result, light conversion efficiency and productivity have a trade-off relationship with each other according to a change in the minimum distance (Δh) between each layer of the diffraction pattern in the thickness direction.

In other words, the light conversion efficiency and productivity are in a characteristic relationship that is difficult to coexist with each other.

Meanwhile, the film including the transmissive 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 the transmissive diffractive optical element of the present invention.

5 to 10 show each step constituting the wafer fabrication process.

First, as shown in FIG. 4, a method of manufacturing a transmissive diffractive optical element and a film including the same of the present invention includes the steps of (a) converting an original image into a DOE (diffraction optical elements) mask; (b) separating the DOE mask into a plurality of unit masks; (c) fabricating each layer of the DOE unit mask; (d) exposing on a substrate; (e) etching; (f) manufacturing a DOE pattern substrate;

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

First, the original image to be displayed by the transmissive diffractive optical element undergoes Fourier transformation to simulate whether target efficiency and intensity are obtained by an actual light source (visible light or laser light). As a specific and non-limiting example of the light source, the light source may be short-wavelength green light (G), red light (R), or blue light (B). However, in the case of green light (G), it is preferable because it is the most visible to the human eye as an observer among natural light and has a higher intensity of light than other wavelengths.

The simulation process may be omitted if necessary.

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

6 shows a step 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 including the transmissive diffractive optical element, which is the final product, cannot accurately represent the final image. see level)

On the other hand, if the DOE mask is designed with an excessively large number (steps), the improvement in light efficiency or clarity perceived by the observer cannot be achieved, and the final product, the transmission type diffractive optical element or the film included in the transmission type diffractive optical element, cannot be achieved. The diffraction pattern 122 becomes too precise and complex, resulting in a decrease in productivity and a problem in yield.

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

8 shows a step of exposing on a silicon substrate.

9 shows the etching step.

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, the diffraction pattern 122 may be formed on the wafer coated with the photoresist by exposing a light source (UV or EUV-based light source) over the reticle disk.

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 on a final wafer.

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

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

Meanwhile, one or a plurality of identical master stamps having the same diffraction pattern 122 may 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 transmissive diffractive optical element through an imprinting process using the master stamp will be described in more detail.

11 shows a flowchart of an imprinting process for manufacturing a DOE from a substrate having a DOE pattern.

12 shows a film including a transmissive diffractive optical element as an example of a final product manufactured through the imprinting process.

First, a fabric tiling process may be performed using one or a plurality of master stamps located on the wafer.

The tiling process is a process for manufacturing a copper plate that can be used to imprint a diffraction pattern 122 of a diffractive optical element on a film including a transmissive diffractive optical element using a replica.

Specifically, in the tiling process, after copying the master stamp on a tiling-only film by machine or manual, tiling is performed according to the size of the film including the transmissive diffractive optical element. As a non-limiting and specific example, the tiling may be performed in a size of about 1,200 mm in width, but may be adjusted according to the size of the final product and/or copper plate.

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

The copper plate manufactured by the tiling process may be implanted with a transmissive diffractive optical element on a film including a transmissive diffractive optical element through a subsequent molding process.

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

The transmissive diffractive optical element, which is manufactured through the molding process and positioned in a film including the transmissive diffractive optical element, is positioned on a base as shown in FIGS. 1 and 12 .

Therefore, in order to manufacture the transmissive diffractive optical element, first, a base and a resin stack on the base on which the transmissive diffractive optical element can be formed must be performed prior to the molding process.

At this time, since the diffractive optical element of the present invention is a transmissive type, the base is preferably a film having high transparency capable of transmitting light.

As a non-limiting and specific example, PET or the like may be used.

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

However, in the case of PET, it is suitable for a base because it has high transparency and high mechanical strength compared to other olefin-based polymers.

The transmissive diffractive optical element positioned on the base may be made of a polymer resin.

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

At this time, the polymer resin may be cured through thermal curing or UV curing.

The laminate of the base and the resin is provided to the master mold of a roll type through a supply roller, and during the molding process, a constant force is applied to the laminate in a similar manner to rolling, and the master mold is applied to the laminate to be operated. The reverse pattern of can be imprinted. Through this, the diffraction pattern 122 constituting the transmissive diffractive optical element may be formed on the stack.

Furthermore, a printed layer on which a trademark or the like is printed may be included on the lower part and/or upper part of the base to increase the identification of the product, if necessary.

In addition, an adhesive layer and/or an adhesive layer and/or a double-sided tape may be laminated to attach or attach a film including the transmissive diffractive optical element to a part to which the transmissive optical element is attached.

A film including the transmissive diffractive optical element of the present invention and a manufacturing method thereof will be described through examples below.

Example

13 shows simulation results of light conversion efficiencies according to the number of steps of a DOE unit mask and R (red), G (green), and B (blue) light sources.

14 shows simulation results of light conversion efficiencies according to the minimum distance (Δh) in the thickness direction between each layer of the DOE diffraction pattern and R (red), G (green), and B (blue) light sources.

Table 1 below shows the result of calculating the light conversion efficiency according to the steps of the DOE mask when the light source is R (red), G (green), and B (blue), respectively.

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

[Table 1]

First, as shown in FIG. 13 and Table 1, it can be seen that the light conversion efficiency increases as the number of stages of the DOE mask implementing the diffraction pattern increases.

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

On the other hand, as the number of DOE masks increased from 3 to 6, the light conversion efficiency showed little change or slightly increased.

The results of FIG. 13 and Table 1 mean that the light conversion efficiency is almost saturated at step 3 or 4 of the DOE mask.

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

At this time, the minimum interval Δh is related to the number of steps of the DOE mask in FIG. 13 and Table 1.

If the DOE mask has one step, two height steps are formed on the diffractive optical element layer 120 as shown in FIG. 9 . Furthermore, if the DOE mask has two steps, four height steps are formed on the diffractive optical element layer 120 . In other words, if the DOE mask has n steps, 2 ⁿ steps are formed on the diffractive optical element layer 120 .

However, as shown in FIG. 1 , the DOE pattern 122 is located on the residue 121 and the uppermost surface of the residue 121 corresponds to the lowermost surface of the DOE pattern 122 . Therefore, if the DOE mask has one step, two height steps are formed on the diffractive optical element layer, which means that the formed DOE pattern 122 is one. As a result, if the DOE mask has n steps, 2 ⁿ steps are formed on the diffractive optical element layer 120, and (2 ⁿ - 1) DOE patterns 122 are formed.

Meanwhile, the result of FIG. 14 shows that the light conversion efficiency according to the change in the height of one layer of the DOE pattern 122 (in other words, the minimum distance (Δh) in the thickness direction between each layer of the diffraction pattern) depends on the wavelength of the incident light. change directly.

When the incident light is green light (G), the light conversion efficiency is almost constant or slightly decreased until the minimum distance (Δh) in the thickness direction between each layer of the diffraction pattern is approximately 50 nm.

On the other hand, when the incident light is green light (G) and the minimum distance (Δh) in the thickness direction between each layer of the diffraction pattern exceeds approximately 195 nm, the light conversion efficiency is greatly reduced.

Meanwhile, when the incident light is red light (R), the light conversion efficiency is almost constant or slightly decreased until the minimum distance (Δh) in the thickness direction between each layer of the diffraction pattern is approximately 60 nm.

On the other hand, when the incident light is red light (R) and the minimum distance (Δh) in the thickness direction between each layer of the diffraction pattern exceeds about 200 nm, the light conversion efficiency is greatly reduced.

In addition, when the incident light is blue light (B), the light conversion efficiency is almost constant or slightly decreased until the minimum distance (Δh) in the thickness direction between each layer of the diffraction pattern is approximately 45 nm.

On the other hand, when the incident light is blue light (B) and the minimum distance (Δh) in the thickness direction between each layer of the diffraction pattern exceeds about 190 nm, the light conversion efficiency is greatly reduced.

Furthermore, as shown in FIG. 14 and Table 1, the maximum efficiency was found to decrease in the order of when the incident light is red light (R) > when green light (G) > when blue light (B) (maximum efficiency of blue light) is the lowest). And the minimum interval (Δh) at which the maximum efficiency appears also decreased in the order of when the incident light is red light (R) > green light (G) > blue light (B) (the minimum interval for blue light is the smallest)

Since the wavelengths of the green light (G), the red light (R), and the blue light (B) are different from each other, it could be expected that the minimum interval (Δh) where the maximum efficiency appears decreases as the wavelength of the incident light decreases.

However, when the incident light is green light (G) and red light (R), it is predicted that the difference in maximum efficiency can be changed according to the pattern design.

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

Furthermore, the results of FIGS. 13 and 14 show that the minimum spacing (Δh) in the thickness direction between each layer of the diffraction pattern is 50 to 195 nm (incident light is green light (G)), 60 to 200 nm (incident light is red light ( R)), or 45 to 190 nm (incident light is blue light (B)) without a significant change in light conversion efficiency (approximately, the light conversion efficiency in the case of red light is 63% or more, and in the case of green light, the light conversion efficiency is 55% Above, in the case of blue light, the light conversion efficiency is 51% or more). This means that a diffraction pattern with excellent productivity can be obtained.

15 shows images (images) of transmitted light according to the steps of a DOE unit mask when the incident light is red light (R), green light (G), blue light (B), and white light (W), respectively.

15 intuitively shows an image of transmitted light actually observed by an observer.

As shown in FIG. 15, as the number of layers constituting the diffraction pattern increases with respect to the total height H of a given diffraction pattern (in other words, the minimum distance (Δh) between each layer of the diffraction pattern in the thickness direction) As this decreases), it can be seen that the image of the transmitted light becomes clearer.

Looking more specifically, as the number of layers constituting the diffraction pattern increases from the 2nd level to the 8th level, the sharpness of the transmitted light is rapidly improved, and thereafter, there is almost no change until the 32nd level.

The results of FIG. 15 agree very well with the results of FIGS. 13 and 14 above.

On the other hand, it can be seen that when the incident light is monochromatic light (ie, red light, green light, or blue light), the image of the 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, and thus light of various wavelengths causes mutual interference.

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 having four different heights), the desired lightning image and the actual image are not the same. can know

On the other hand, as shown in FIGS. 17 and 18, there are 3 DOE unit masks (FIG. 17, 8 diffraction patterns 122 having different heights) and 5 (FIG. 18, 32 diffraction patterns 122 having 32 different heights). )), 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 distinguish clearly with the naked eye.

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

As described above, the present invention has been described with reference to the drawings illustrated, but the present invention is not limited by the embodiments and drawings disclosed herein, and various modifications are made by those skilled in the art within the scope of the technical idea of the present invention. It is obvious that variations can be made. In addition, although the operational effects according to the configuration of the present invention have not been explicitly described and described while describing the embodiments of the present invention, it is natural that the effects predictable by the corresponding configuration should also be recognized.

Claims (15)

1. In the transmissive diffractive optical element comprising a diffraction pattern,

   The diffraction pattern includes a plurality of layers,

   The minimum spacing (Δh) in the thickness direction between the plurality of layers is 45 to 200 nm,

   A transmissive diffractive optical element wherein the diffraction pattern has a total height (H) of 800 to 13500 nm.
2. According to claim 1,

   The minimum spacing (Δh) in the thickness direction between the plurality of layers is 60 to 200 nm,

   The light conversion efficiency of the diffractive optical element is a value calculated by Equation 1 below of 63% or more, the transmissive diffractive optical element.

   (Equation 1)

   

   (In Equation 1 above, {U _sig (x')} ² means the Intensity of the Desired Output Field, and {U _in (ξ)} ² below means the Intensity of the Input Field, and the alpha value is As a scaling factor, it corresponds to a kind of correction value to reduce the error between the desired result area (Desired Output Field) and the calculated intensity of the output field. means the position value in the input field, and W _sig means the Optimization Region.)
3. According to claim 1,

   The minimum spacing (Δh) in the thickness direction between the plurality of layers is 50 to 195 nm,

   The light conversion efficiency of the diffractive optical element is a value calculated by Equation 1 above of 55% or more, the transmissive diffractive optical element.
4. According to claim 1,

   The minimum spacing (Δh) in the thickness direction between the plurality of layers is 45 to 190 nm,

   The light conversion efficiency of the diffractive optical element is a value calculated by Equation 1 above of 51% or more, the transmissive diffractive optical element.
5. Base;

   A transmissive diffractive optical element layer disposed on the base and including a diffraction pattern;

   The diffraction pattern 122 includes a plurality of layers,

   The minimum spacing (Δh) in the thickness direction between the plurality of layers is 45 to 200 nm,

   A film comprising a transmissive diffractive optical element layer in which the total height (H) of the diffraction pattern is 800 to 1350 nm.
6. According to claim 1,

   The minimum spacing (Δh) in the thickness direction between the plurality of layers is 60 to 200 nm,

   A film comprising a transmissive diffractive optical element layer, wherein the light conversion efficiency of the diffractive optical element is 63% or more as calculated by Equation 1 above.
7. According to claim 1,

   The minimum spacing (Δh) in the thickness direction between the plurality of layers is 50 to 195 nm,

   A film comprising a transmissive diffractive optical element layer, wherein the light conversion efficiency of the diffractive optical element is 55% or more, calculated by Equation 1 above.
8. According to claim 1,

   The minimum spacing (Δh) in the thickness direction between the plurality of layers is 45 to 190 nm,

   A film comprising a transmissive diffractive optical element layer, wherein the light conversion efficiency of the diffractive optical element has a value calculated by Equation 1 above of 51% or more.
9. According to claim 5,

   A film comprising a transmissive diffractive optical element layer comprising a residue positioned between the diffraction pattern and the base.
10. According to claim 5,

    The film comprising a transmission-type diffractive optical element layer in which the base is transparent PET.
11. According to claim 5,

    The film comprising a transmissive diffractive optical element layer in which the diffractive optical element layer is a urethane-based or acrylic-based resin.
12. According to claim 5,

    A film comprising a transmissive diffractive optical element layer further comprising an adhesive layer, an adhesive layer, or a double-sided tape positioned below the base.
13. According to claim 5,

    A film comprising a transmissive diffractive optical element layer further comprising a printing layer disposed above and/or below the base.
14. (a) converting an original image into a diffraction optical elements (DOE) mask through Fourier transform and inverse Fourier transform;

    (b) separating the DOE mask into 3, 4 or 5 DOE unit masks;

    (c) manufacturing each of the 3, 4 or 5 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.
15. (a) converting an original image into a diffraction optical elements (DOE) mask through Fourier transform and inverse Fourier transform;

    (b) separating the DOE mask into 3, 4 or 5 DOE unit masks;

    (c) manufacturing each of the 3, 4 or 5 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 method for manufacturing a film comprising a transmissive diffractive optical element layer comprising:

Images