KR102036759B1 - Multi-functional film with simultaneous color filter and phase retardation functions - Google Patents

Abstract

A multifunctional film having a color filter function and a retardation film function, the first layer comprising a plurality of structures formed on a substrate and formed by a first material having a refractive index n ₁ , and a second material having a refractive index n ₂ . And a second layer formed by the refractive index n ₁ is The refractive index is greater than n ₂ , wherein the plurality of structures are spaced apart from each other, and the structure included in the first layer relates to a multifunctional film, which is disposed inside the second layer.

Description

Multi-functional film with simultaneous color filter and phase retardation functions}

This application relates to the multifunctional film which has a color filter function and a retardation film function simultaneously.

The demand for ultra-thin, high-performance displays, such as UHD displays, flexible displays, and transparent displays, which are recently presented as future displays, is increasing. In order to realize a thin, high-performance display, there is a need to revolutionize the thickness and resolution of panels in currently commercialized displays. However, since a plurality of various elements, such as a color filter, an antireflection film, a polarizing plate, a retardation film, and a compensation film, are used as an essential component of a display element, the total thickness has a problem that it is difficult to reduce the thickness of the element to several hundred microns or more.

The color filter can express colors by transmitting or reflecting a specific wavelength in the visible light band, and the retardation film blocks light leakage in the LCD display to obtain high contrast ratio and color reproduction, and suppresses external light reflection in the OLED display. Do it. Conventional retardation film has a problem that the difference in refractive index according to the direction is small, the thickness is increased to make the desired retardation, the color filter and the retardation film is produced by overlapping, there is a problem that the thickness is further increased.

In this regard, Republic of Korea Patent Publication No. 2015-0034021, the biaxially stretched base film having a phase difference characteristic; And a coating layer formed on at least one surface of the base film and having a negative retardation characteristic and uniaxially stretched in the width direction (TD) and a method of manufacturing the retardation film.

In order to solve the above-mentioned problem, an object of the present invention is to provide a multifunctional film having a color filter function and a retardation film function.

Another object of the present invention is to provide a thin film optical element by implementing a color filter function and a retardation film function in a multifunctional film at once.

However, the problem to be solved by the present application is not limited to the above-mentioned problem, another task that is not mentioned will be clearly understood by those skilled in the art from the following description.

A first aspect of the present application is a multifunctional film having a color filter function and a retardation film function, the first layer including a plurality of structures formed on a substrate and formed by a first material having a refractive index n ₁ and a refractive index. a second layer formed by a second material having n ₂ , wherein the refractive index n ₁ is The refractive index is greater than n ₂ , wherein the plurality of structures are spaced apart from each other, and the structure included in the first layer is disposed inside the second layer, to provide a multifunctional film.

In embodiments of the present disclosure, a multifunctional film capable of reducing the thickness of the device may be provided by using a multifunctional film having two functions of a retardation film and a color filter in a conventional device. Specifically, the multifunctional film according to embodiments of the present invention is formed on a substrate, the first layer comprising a plurality of structures formed by the first material having a refractive index n ₁ and a second material having a refractive index n ₂ And a second layer formed by the refractive index n ₁ is The refractive index is greater than n ₂ , wherein the plurality of structures are spaced apart from each other, and the structures included in the first layer may be disposed inside the second layer.

The multifunctional film according to the embodiments of the present invention has the effect of simplifying the process because the color filter and the retardation film can be implemented by one design of the same structure.

In the embodiments of the present invention, in terms of the color filter, the structure is a structure using a metal, inorganic, or organic / inorganic hybrid-based material having a size (subwavelength) smaller than the wavelength, having a high refractive index difference Using a design, the color filter has the effect of having high transmission or reflectance, wide color gamut, and high color purity. In addition, also in the side of the retardation film, by using the material having a high refractive index difference there is an effect of greatly reducing the thickness by increasing the refractive index difference along the direction.

Figure 1 (a) is a schematic diagram of a composite structure having a high refractive index difference including a color filter function in one embodiment of the present application, Figure 1 (b) is a color filter function in an embodiment of the present application A graph showing a simulation result of a composite structure having a high refractive index difference including.
2 (a) is a schematic diagram of a composite structure having a high refractive index difference including the function of the retardation film in one embodiment of the present application, Figure 2 (b) is a retardation film in one embodiment of the present application It is a graph showing the simulation results of a composite structure having a high refractive index difference including the function of.
3A to 3C are schematic views for explaining a structure having resonance in a predetermined wavelength region in one embodiment of the present application.
4A is a schematic diagram for explaining a unit structure of structures according to an example and a comparative example of the present application.
4B and 4C are graphs showing simulation results of the structures of FIG. 4A according to one embodiment of the present disclosure.
5 (a) and 5 (b) are schematic diagrams for explaining the structure of a multifunctional film based on a blue wavelength according to one embodiment of the present application.
6A to 6C are graphs showing simulation results of a multifunctional film based on a blue wavelength according to an embodiment of the present application.
7 is a graph illustrating a phase difference according to a height of a multifunctional film based on a blue wavelength according to an embodiment of the present application.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present disclosure. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted for simplicity of explanation, and like reference numerals designate like parts throughout the specification.

Throughout this specification, when a part is said to be "connected" with another part, this includes not only the "directly connected" but also the "electrically connected" between other elements in between. do.

Throughout this specification, when a member is located “on” another member, this includes not only when one member is in contact with another member but also when another member exists between the two members.

Throughout this specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding the other components unless otherwise stated. As used throughout this specification, the terms “about”, “substantially”, and the like, are used at, or in close proximity to, numerical values when manufacturing and material tolerances inherent in the meanings indicated are provided, and an understanding of the present application may occur. Accurate or absolute figures are used to assist in the prevention of unfair use by unscrupulous infringers. As used throughout this specification, the term “step of” or “step of” does not mean “step for”.

Throughout this specification, the term "combination (s) thereof" included in the expression of a makushi form refers to one or more mixtures or combinations selected from the group consisting of components described in the expression of makushi form, It means to include one or more selected from the group consisting of the above components.

Throughout this specification, the description of “A and / or B” means “A or B, or A and B”.

Throughout this specification, "refractive index" refers to the ratio of the speed at which the phase of light advances in vacuum divided by the speed running in the medium. The refractive index varies with wavelength, and at the interface of the media with different refractive indices, the light bends according to Snell's law and some reflects according to the angle of incidence. The refractive index may be expressed as a square root of the product of relative permittivity and relative permeability, as shown in Equation 1 below, and as the refractive index value increases, resolution, which is an ability to distinguish two objects from each other in an optical device, is improved. Because the resolution increases:

[Equation 1]

(n = 굴절률, ε = 상대 유전율, μ = 상대 투자율)

(n = refractive index, ε = relative permittivity, μ = relative permeability)

Hereinafter, with reference to the accompanying drawings will be described embodiments and embodiments of the present application; However, the present disclosure may not be limited to these embodiments, examples, and drawings.

A first aspect of the present application is a multifunctional film having a color filter function and a retardation film function, the first layer including a plurality of structures formed on a substrate and formed by a first material having a refractive index n ₁ and a refractive index. a second layer formed by a second material having n ₂ , wherein the refractive index n ₁ is The refractive index is greater than n ₂ , wherein the plurality of structures are spaced apart from each other, and the structure included in the first layer is disposed inside the second layer, to provide a multifunctional film.

In one embodiment of the present application, as shown in Fig. 1 (a) and 2 (a), a first layer 200 including a plurality of structures are formed on the substrate 100, the first The second layer 300 is formed by the second material on the surface of the structure of the first layer 200 and / or on the first layer 200. For example, the structure may be disposed inside the second material, or the height of the first layer 200 and the second layer 300 may be the same or completely overlap each other. In this case, the structure is surrounded by the second material in the x and y directions, but not the second material in the z direction.

In one embodiment of the present application, by using a multifunctional film having two functions of a retardation film and a color filter in a conventional device, it is possible to provide a multifunctional film capable of reducing the thickness of the device. Retardation films currently used in commercial devices are usually tens of micrometers, at least a few micrometers thick, and color filters are also a few micrometers thick (i.e. twice the thickness of the wavelength). On the other hand, the multifunctional film according to one embodiment of the present application may have two functions of a phase difference film and a color filter simultaneously in one film, and may have a thickness of less than twice the wavelength, for example, visible The light ray can be implemented to a thickness of about 100 nm to about 1 μm.

In one embodiment of the present application, the multifunctional film, a first layer comprising a plurality of structures formed by a first material having a refractive index n ₁ on the substrate is formed, the refractive index on the first layer A second layer including a second material having n ₂ is formed, and the plurality of structures spaced apart from each other may be disconnected and the empty portion may be filled with the second material, but may not be limited thereto.

In one embodiment of the present application, by adjusting the length or arrangement period of the two axes parallel to and perpendicular to the substrate of the structure, it is possible to produce a multifunctional film having a color filter function and a retardation film function (see FIG. 3). ).

In one embodiment of the present application, each of the plurality of structures included in the first layer may have an anisotropic structure (see FIG. 3A). For example, when the structure has a rectangular parallelepiped or rod-shaped anisotropic structure, each of the plurality of structures included in the first layer may have different lengths in each direction of two axes parallel to and perpendicular to the substrate. The plurality of structures included in the first layer may be spaced apart at equal intervals in one direction (see FIG. 3A).

In another embodiment of the present invention, the plurality of structures included in the first layer has a two-dimensional array structure that is spaced apart at different periods in each direction in each direction of two axes parallel to and perpendicular to the substrate. Can be. For example, the structure may be anisotropic or the top and bottom surfaces of the structure parallel to the substrate may be isotropic, and the plurality of structures included in the first layer may be of two axes parallel to and perpendicular to the substrate. It may have a two-dimensional array structure that is spaced apart at different periods in each direction (see FIGS. 3B and 3C).

In one embodiment of the present application, for example, the arrangement of the plurality of structures included in the first layer, the plurality of structures included in the first layer are each direction of two axes parallel to and perpendicular to the substrate Two-dimensional array structures spaced at different intervals from each other, and / or each of the plurality of structures included in the first layer has a different length from each other in two directions parallel to and perpendicular to the substrate, The plurality of structures included in the first layer may be spaced apart at equal intervals in one direction (see FIG. 3A).

In one embodiment of the present application, the structure may include, but is not limited to, an anisotropic structure such as a rectangular parallelepiped, a rod, an elliptic cylinder, a semi-ellipse, or a lying semi-circular cylinder. For example, the rectangular parallelepiped may include a strip form, but may not be limited thereto.

In one embodiment of the present application, each of the period and the width of the arrangement of the structure included in the first layer, may be of a subwavelength (subwavelength) length of less than 1/2 of the target wavelength, it is included in the first layer The height of the structure may be less than twice the length of the target wavelength. The period of the arrangement of the structures may be defined by the period p _{x in the x-} axis direction and the period p _y in the y-axis direction shown in FIG. 3.

In one embodiment of the invention, the first material is a metal, metal mixture, alloy; Inorganic, organic / inorganic hybrid materials; And combinations thereof selected from the group consisting of:

For example, the inorganic material may include an oxide, a nitride, a semiconductor having a bandgap larger than visible light, or a dielectric material, but may not be limited thereto.

For example, the oxide may include SiO ₂ , ZnO, Al ₂ O ₃ , ITO, TiO ₂ , ZrO ₂ , HfO ₂ , or SnO ₃ , and the nitride may be Si ₃ N _4. or It may be to include nitrides of the transition metal, but may not be limited thereto. For example, the semiconductor having a bandgap larger than the visible light may include AlGaN and the like, and the dielectric material may include SiC and the like, but is not limited thereto.

In one embodiment of the present application, the second material may be a gas phase material, a liquid material, or a solid material. For example, the gaseous substance may include air, nitrogen, or an inert gas, and the inert gas may specifically include argon gas, but may not be limited thereto. For example, the solid material may be a low refractive index dielectric material such as SiO ₂ , MgF ₂ , NaF, or poly (methyl methacrylate), polystyrene, polycarbonate, or the like. It may include an organic material or a material including pores such as expanded polystyrene, but may not be limited thereto.

In one embodiment of the present application, the wavelength at which the multifunctional film may operate may include a microwave section, an infrared section, a near infrared section, a visible light section, an ultraviolet section, or an X-ray section.

Multifunctional film according to an embodiment of the present application has the effect of simplifying the process because the color filter and the retardation film can be implemented by one design of the same structure.

In one embodiment of the present application, in the aspect of the color filter, using a structural design using a metal, inorganic, or organic / inorganic hybrid-based material having a size (subwavelength) smaller than the wavelength, having a high refractive index difference Thus, the color filter has an effect of having high transmission or reflectance, wide color gamut, and high color purity. In addition, also in the side of the retardation film, by using the material having a high refractive index difference there is an effect of increasing the refractive index difference along the direction to significantly reduce the thickness.

Hereinafter, the embodiments of the present application will be described in detail. However, the present application may not be limited thereto.

[ Example ]

1A is a schematic diagram of a composite structure having a high refractive index difference including a color filter function, and FIG. 1B is a graph showing a simulation result of a composite structure having a high refractive index difference including a color filter function. to be.

In FIG. 1A, the rectangular parallelepiped structures formed on the substrate are a plurality of structures formed by a first material having a refractive index n ₁ , and external materials surrounding the structures are formed by a second material having a refractive index n ₂ . Second layer. By adjusting the shape of the structure according to the width and period in the x-axis or y-axis direction and the height in the z-axis direction of the structure shown in FIG. 1A, the incident light and the resonance wavelength of the structure can be adjusted, and visible light The wavelength characteristics such as wavelength and bandwidth at which transmission and reflection occur in the band can be controlled.

As shown in the simulation result shown in FIG. 1 (b), it has a maximum reflectance and a minimum transmittance in the vicinity of the wavelength of about 532 nm, and the reflectance is very high in the wavelength region from 500 nm to 550 nm, while the transmittance is low. I could confirm it.

FIG. 2A is a schematic diagram of a strip-shaped structure having a high refractive index difference including a function of a retardation film, and FIG. 2B is a simulation of a composite structure having a high refractive index difference including a function of a retardation film. A graph showing the results.

Like the strip-shaped structure shown in FIG. 2A, a difference in refractive indexes in the x-axis direction and the y-axis direction of the structure may be differently manufactured, and a phase difference film in which a phase difference occurs depending on the polarization direction may be designed.

FIG. 2 (b) shows a result of simulating the phase difference due to the x-axis polarization and the y-axis polarization according to the height in the z-axis direction of the structure shown in FIG. By adjusting the parameters (width, period, or thickness) of the structure, anisotropic effective refractive index is obtained, and anisotropy can be used to design a structure for a retardation film having a thin thickness. Can be.

3A to 3C are schematic diagrams for explaining a structure having resonance in a predetermined wavelength region.

In FIG. 3, the period in the x-axis direction is represented by p _x , the period in the y-axis direction is represented by p _y, and the shape of the structure formed on the substrate is shown in FIG. 3 (b) is a rectangular parallelepiped, and FIG. 3 (c) is a cylinder.

Of Figure 3 (a) is a rectangular parallelepiped having an array of rectangular prism (strip-shaped) having a million cycles in the x-axis direction, FIG. 3 (b) is the x-axis direction and y each other period in the axial direction p _x and p _y of 3C shows an array of cylinders having different periods p _x and p _y in the x-axis direction and the y-axis direction, respectively. By adjusting the parameters of each structure, an electromagnetic resonance phenomenon occurs at a target wavelength to change the transmittance and reflectance of the corresponding wavelength relative to other wavelengths, and due to anisotropic structure or different periods, polarization and y-axis directions in the x-axis direction It is possible to make the transmission phases of polarized light appear differently.

4A is a schematic diagram for explaining the unit structures of the structures 1, 2, and 3 according to the present embodiment, and the structures 4 and 5 according to the comparative example, and FIGS. 4B and 4C are simulations of the structures of FIG. 4A. A graph showing the results.

The structure 1, the structure 2, and the structure 3 correspond to the schematic diagrams shown in FIG. 3 (a), and the width w in the x-axis direction, the period p, and the height t in the z-axis direction It is different.

The structure 1 has a period (p) of 330 nm, a width (w) of 130 nm, a height (t) of 100 nm, and the structure 2 has a period (p) of 255 nm, a width (w) of 205 nm, and a height. (t) is 130 nm, and the structure 3 has a period p of 280 nm, a width w of 195 nm, and a height t of 100 nm.

As a comparative example, the structures of the structures 4 and 5 are structures having an isotropic structure, not an anisotropic structure. The structures 4 and 5 correspond to the schematic diagram shown in FIG. 3 (b), wherein the structure 4 has a period p of 305 nm, a width w of 195 nm, and a height t of 100 nm. The arrangement is repeated in the x-axis direction and the y-axis direction. The structure 5 corresponds to the schematic diagram shown in (c) of FIG. 3, the structure 5 has a period (p) of 330 nm, a diameter corresponding to the width (w) is 195 nm, height (t) is 100 nm, The cylindrical arrangement is repeated in the x-axis and y-axis directions.

As described with reference to FIGS. 1 and 2, the structures 1 to 5 may be used as color filters because the reflectance is measured only in a specific wavelength region, and the structures 1 to 3 may be used in the x-axis polarization and the y-axis polarization. It can also be used as a retardation film whose phase is different with respect to.

Simulations were performed assuming that the inorganic structure materials constituting the structure with respect to the structures 1 to 5 had a refractive index of 2.7 and the refractive index of the material surrounding the structure was 1.45. It is shown in Figure 4b to calculate the wavelength-specific reflection graph for the x polarized light of the structures 1 to 3, and to calculate the wavelength-specific reflection graphs of the structures 2, 4, and 5 is shown in Figure 4c. The structures 1 to 5 all have resonance at a wavelength of 532 nm, and it was confirmed that high efficiency reflectance can be obtained in a predetermined wavelength region.

The phase difference of the structure having resonance corresponding to that of the structures 1 to 5 is shown in Table 1 below.

TABLE 1

Table 1 shows the phase difference between the electromagnetic wave polarized in the x-axis direction and the electromagnetic wave polarized in the y-axis direction, and the structures 4 and 5 having only the color filter function have the same effective refractive index in the x-axis direction and the y-axis direction. Is 0, and the structures 1 to 3 do not have a phase difference of 0 due to the difference in the effective refractive index, and as the height is adjusted, a desired phase difference can be obtained between 0 degrees and 360 degrees such as 90 degrees, 180 degrees, and the like. It can be used as a retardation film. In addition, even if the resonance of the same wavelength is the same, the phase difference may be different. Therefore, if the parameters in the x-axis direction and the y-axis direction are properly adjusted, phase control together with wavelength control is possible, and resonance is performed at the same wavelength (color filter function). A multifunctional film capable of obtaining a desired retardation (retardation film) can be implemented.

5A and 5B are schematic views for explaining the structure of a multifunctional film having a color filter function and a retardation film function based on a blue wavelength. 5B illustrates a multi-functional film having a period of 290 nm, a width of 145 nm, a period of 130 nm, and a width of 65 nm in the y-axis direction as a specific example of FIG. 5A.

6A to 6C are graphs showing simulation results of the multifunctional film on a blue wavelength basis.

6A to 6C are simulation results based on the model of FIG. 5B. Specifically, FIG. 6A illustrates resonant wavelengths of heights of a rectangular parallelepiped with respect to x-axis polarization, and FIG. 6B illustrates y-axis. Resonant wavelengths of the heights of the rectangular parallelepiped with respect to the directional polarization are shown, and FIG. 6C illustrates a reflection graph with respect to the height (about 95 nm) of the rectangular parallelepiped resonating at a wavelength of 460 nm in FIGS. 6A and 6B.

Referring to FIG. 6C, the color filter function having high efficiency reflection on the same wavelength in both the x-axis polarization and the y-axis polarization was confirmed. Here, it is assumed that the refractive index of the structure material constituting the structure is 2.7, and the refractive index of the material surrounding the structure is 1.45. In the arrangement of the x-axis direction and the y-axis direction, a rectangular parallelepiped structure having different periods p and widths w was used as shown in FIG. The height t in the z-axis direction is the same.

6C, both the polarization in the x-axis and the polarization in the y-axis have resonance at the same wavelength, but since there is a difference in the effective refractive indices in the x-axis and the y-axis, a phase difference exists between the two polarizations.

7 is a graph showing the phase difference according to the height of the multifunctional film based on the blue wavelength according to an embodiment of the present application.

이고, 상기 구조체를 이루는 직육면체의 높이가 95 nm일 때, 위상차가 3π/2 가 도시되어 있다. 즉, 직육면체의 두께를 조절함으로써 원하는 위상차를 얻을 수 있다.As shown in Fig. 7, since there is a difference between the effective refractive indices in the x-axis direction and the y-axis direction, there is a phase difference between the two polarizations. Phase difference

When the height of the rectangular parallelepiped constituting the structure is 95 nm, the phase difference is 3π / 2. That is, desired phase difference can be obtained by adjusting the thickness of a rectangular parallelepiped.

The above description of the present application is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present application. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present application is indicated by the following claims rather than the above description, and it should be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalents are included in the scope of the present application.

100: substrate
200: first layer
300: second layer

Claims (9)

As a multifunctional film having a color filter function and a retardation film function,
A first layer formed on the substrate, the first layer comprising a plurality of structures formed by a first material having a refractive index n ₁ and a second layer formed by a second material having a refractive index n ₂ ,
The refractive index n ₁ is the Refractive index is greater than n ₂ ,
The plurality of structures are arranged spaced apart from each other,
Each of the plurality of structures included in the first layer has an anisotropic structure,
The structure included in the first layer is disposed inside the second layer,
Each of the plurality of structures included in the first layer has a two-dimensional array structure that is spaced at different periods from each other in each direction of two axes parallel to and perpendicular to the substrate, or parallel to the substrate. And have different lengths in each direction of two axes perpendicular to each other, and the plurality of structures included in the first layer are arranged at equal intervals in one direction.
Each of the period and the width of the arrangement of the structure included in the first layer is a subwavelength of less than 1/2 of the target wavelength,
The height of the structure included in the first layer is less than twice the target wavelength,
Multifunctional film.
The method of claim 1,
The first material may be a metal, a metal mixture, an alloy; Inorganic, organic / inorganic hybrid materials; And those selected from the group consisting of combinations thereof.
The method of claim 1,
Wherein the second material comprises a gaseous material, a liquid material, or a solid material.
delete delete delete The method of claim 1,
The structure is a multi-functional film that comprises a cuboid, ellipsoid, semi-ellipse, or lying semi-circular cylinder.
delete The method of claim 1,
The wavelength at which the multifunctional film operates includes a microwave section, an infrared section, a near infrared section, a visible light section, an ultraviolet section, or an X-ray section.

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