KR101510725B1 - Active surface plasmonic color filter including anisotropic patterns, and display device including the same - Google Patents

Abstract

The active surface plasmon color filter includes a substrate, a metal thin film formed on the substrate and arranged periodically and including a plurality of holes each having a nano size, and a first dielectric layer formed on the metal thin film do. The holes included in the metal thin film are arranged periodically in a first directional axis and a second directional axis perpendicular to each other so as to adjust the color according to the polarization direction of the linearly polarized light provided from the outside, And the intervals of the holes disposed in the second directional axis are different from each other. An active surface plasmon color filter capable of gradation display is provided on a substrate and is arranged on the substrate and arranged periodically so as to adjust the intensity of linearly polarized light according to the polarization direction of linearly polarized light incident from the outside and has a nano- A metal thin film including a plurality of holes each having a shape and a first dielectric layer formed on the metal thin film, wherein the holes included in the metal thin film are a square unit hole array pattern It is repeatedly arranged in the shape of a regular hexagon unit hole array.

Description

[0001] The present invention relates to a display device including an active surface plasmonic color filter including an anisotropic pattern, and an active surface plasmonic color filter including an active surface plasmonic color filter including anisotropic patterns,

The present invention relates to surface plasmonic color filter technology, and more particularly, to an active surface plasmonic color filter including an anisotropic pattern, and a display device including the active surface plasmonic color filter.

The liquid crystal display (LCD), which is the mainstream of the flat panel display market, implements colors by selectively transmitting red, green, and blue light using a white light source through a backlight and a liquid crystal layer using a color filter. In order to express a gray scale for each color, a liquid crystal display is driven in such a manner that the amount of light transmitted through the liquid crystal layer is adjusted by adjusting the amount of change of the liquid crystal layer. For this purpose, All require a polarizer. A color filter of a flat panel display that is commercialized absorbs light of a certain color depending on the material characteristics of the pigment or dye and colors are implemented by transmitting and reflecting only light of a specific wavelength band. have. Since light emitted from a backlight must pass through many structures such as a polarizer, a liquid crystal layer, and a color filter layer of two layers, the power consumption of the backlight increases for high light efficiency.

On the other hand, the present invention can be applied to a color filter using a surface plasmon generated in a metal thin film layer forming a pattern composed of a plurality of nano-sized holes having periodicity. The surface plasmon resonance phenomenon plays a role of increasing the amount of light of a specific wavelength band transmitted through a metal thin film, and the period of the hole array pattern, the size of the hole, the shape of the hole, Or the thickness of the metal thin film or the like can be adjusted to change the wavelength band. The surface plasmonic color filter using the surface plasmon is formed by a simple structure and configuration using a thin film of a metal and a dielectric to overcome the material limit of the color filter based on the conventional pigment or dye, And has the advantage of achieving the transmittance.

One example of a surface plasmonic color filter is disclosed in Korean Patent Laid-open Nos. 10-2011-0120722 and 10-2011-0070571. Although the present invention (the invention of the present application) uses metal layers of various types of periodic patterns, it is limited to a square grid, a regular hexagonal grid, or a regular triangular grid. In the present invention, since the intervals between adjacent holes are the same, the present invention has a single periodicity. Although the present invention does not have any particular limitation on the shape (shape) of a hole such as a circle, a rectangle, a triangle, a slit, or an ellipse, all of them are intended to be used for the purpose of maintaining constant transmission of a specific color .

Another example of a surface plasmonic color filter is disclosed in Korean Patent Laid-open Nos. 10-2011-0070574 and 10-2011-0120718.

The hole patterns in the hole periodicity pattern of the invention disclosed in Korean Patent Laid-open Nos. 10-2011-0120722, 10-2011-007057, 10-2011-0070574, and 10-2011-0120718 are circular, triangular, square, It looks like a slit. The pattern serves to uniformly transmit only a specific color.

The invention described in Korean Patent Publication No. 10-2011-0120718 selectively transmits linearly polarized light using a 1D array slit.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a method of manufacturing a light emitting device, which is based on a surface plasmonic color filter including a metal thin film having a hole array, An active surface plasmonic color filter including an anisotropic pattern or a new concept active surface plasmonic color filter using a surface plasmon resonance characteristic capable of adjusting the transmittance according to the polarization of light transmitted through the structure, And a display device.

According to an aspect of the present invention, there is provided an active surface plasmonic color filter comprising: a substrate; A metal thin film formed on the substrate, the metal thin film including a plurality of holes arranged periodically and each having a nano size; And a first dielectric layer formed on the metal thin film. The holes included in the metal thin film may include a first direction axis perpendicular to the first direction axis and a second direction axis perpendicular to the first direction axis, The intervals of the holes arranged periodically in the second directional axis and arranged in the first directional axis and the intervals of the holes arranged in the second directional axis may be different from each other.

The active surface plasmon color filter may further include a second dielectric layer formed between the substrate and the metal thin film, wherein the dielectric material included in the first dielectric layer and the dielectric material included in the second dielectric layer are the same can do. The substrate may be a glass substrate or a plastic substrate.

According to another aspect of the present invention, there is provided an active surface plasmonic color filter comprising: a substrate; A metal thin film formed on the substrate, the metal thin film including a plurality of holes arranged periodically and each having a nano size; And a first dielectric layer formed on the metal thin film. The holes included in the metal thin film may have an anisotropic shape so that the intensity of the linear polarized light is adjusted according to the polarization direction of the linearly polarized light provided from the outside. The intervals of the holes arranged periodically in the first directional axis and the second directional axis perpendicular to each other and arranged in the first directional axis and the intervals of the holes arranged in the second directional axis may be the same.

Each of the holes having an anisotropic shape includes a shape having a different length in the longitudinal direction and the transverse direction, and may have an elliptical shape, a rectangular shape, or a hexagonal shape.

The active surface plasmon color filter may further include a second dielectric layer formed between the substrate and the metal thin film, wherein the dielectric material included in the first dielectric layer and the dielectric material included in the second dielectric layer are the same can do.

According to another aspect of the present invention, there is provided an active surface plasmonic color filter comprising: a substrate; And a plurality of holes each having a nano-sized anisotropic shape so as to adjust the intensity of the linearly polarized light according to the polarization direction of the linearly polarized light incident from the outside ; And a first dielectric layer formed on the metal thin film. The holes included in the metal thin film may be repeatedly arranged in a unit hole array pattern of a regular hexagon.

Each of the holes having an anisotropic shape includes a shape having a different length in the longitudinal direction and the transverse direction, and may have an elliptical shape, a rectangular shape, or a hexagonal shape. The active surface plasmon color filter may further include a second dielectric layer formed between the substrate and the metal thin film, wherein the dielectric material included in the first dielectric layer and the dielectric material included in the second dielectric layer are the same can do.

According to an aspect of the present invention, there is provided a display device comprising: a substrate; a metal layer formed on the substrate, the metal layer including a plurality of holes periodically arranged in the nano- An active surface plasmon color filter including a thin film and a first dielectric layer formed on the thin metal film; A liquid crystal layer for adjusting the polarization direction of the linearly polarized light and making the light enter the active surface plasmon color filter in response to a voltage applied between the first conductive layer and the second conductive layer; And a linear polarizer that linearly polarizes the light generated from the backlight unit and provides the linear polarized light to the liquid crystal layer, wherein the holes included in the metal thin film of the active surface plasmon color filter include a polarization direction of the linearly polarized light Wherein a distance between the holes arranged in the first direction axis and a distance between the holes arranged in the second direction axis are set to be shorter than a distance between the first direction axis and the second direction axis, May be different.

The active surface plasmon color filter may further include a second dielectric layer formed between the substrate and the metal thin film, wherein the dielectric material included in the first dielectric layer and the dielectric material included in the second dielectric layer are the same can do.

The brightness of light emitted from the backlight unit can be adjusted so that the display device can express a gray scale. Each of the first conductive layer and the second conductive layer may include a conductive transparent dielectric material. The material contained in the first dielectric layer and the material contained in the second conductive layer may be the same.

According to another aspect of the present invention, there is provided a display device including a substrate, a plurality of holes formed on the substrate and periodically arranged and each having a nano size, An active surface plasmon color filter including a metal thin film and a first dielectric layer formed on the metal thin film; A liquid crystal layer for adjusting the polarization direction of the linearly polarized light and making the light enter the active surface plasmon color filter in response to a voltage applied between the first conductive layer and the second conductive layer; And a linear polarizer that linearly polarizes the light generated from the backlight unit and provides the linear polarized light to the liquid crystal layer, wherein the holes included in the metal thin film of the active surface plasmon color filter include a polarization direction of the linearly polarized light And the pitches of the holes arranged in the first directional axis and periodically arranged in the first directional axis and the second directional axis which are perpendicular to each other and which are respectively anisotropic in shape so that the intensity of the linearly polarized light is adjusted according to the intensity The spacing of the holes disposed in the directional axis may be equal to each other.

The active surface plasmon color filter may further include a second dielectric layer formed between the substrate and the metal thin film, wherein the dielectric material included in the first dielectric layer and the dielectric material included in the second dielectric layer are the same can do. The material contained in the first dielectric layer and the material contained in the second conductive layer may be the same.

According to another aspect of the present invention, there is provided a display device including a substrate, a plurality of holes formed on the substrate and periodically arranged and each having a nano size, An active surface plasmon color filter including a metal thin film and a first dielectric layer formed on the metal thin film; A liquid crystal layer for adjusting the polarization direction of the linearly polarized light and making the light enter the active surface plasmon color filter in response to a voltage applied between the first conductive layer and the second conductive layer; And a linear polarizer that linearly polarizes the light generated from the backlight unit and provides the linear polarized light to the liquid crystal layer, wherein the holes included in the metal thin film of the active surface plasmon color filter include a polarization direction of the linearly polarized light And may be repeatedly arranged in a unit hole array pattern having a regular hexagonal shape such that the intensity of the linearly polarized light is adjusted according to the shape of the linear polarized light.

The active surface plasmon color filter may further include a second dielectric layer formed between the substrate and the metal thin film, wherein the dielectric material included in the first dielectric layer and the dielectric material included in the second dielectric layer are the same can do. The material contained in the first dielectric layer and the material contained in the second conductive layer may be the same.

The active surface plasmonic color filter structure according to the present invention includes a metal thin film formed with a hole array pattern of a rectangular lattice structure having a period of different sizes in the longitudinal and transverse directions, The transmission peak wavelength can be adjusted by using the property that the transmission peak wavelength of the formed metal thin film is affected by the polarization characteristic of the incident light. Therefore, the display device according to the present invention using the active surface plasmonic color filter structure can be used as a simple structure of a surface plasmonic color filter of the present invention, in which a polarizing plate in a conventional liquid crystal display device and a dye or pigment- The present invention can simplify the structure of the existing liquid crystal display and the processing procedure of the existing liquid crystal display structure and reduce the processing cost of the conventional liquid crystal display structure.

The color filter according to the present invention can solve the problem of low transmittance according to the material characteristics of the color filter using the pigment or dye by utilizing the improvement of the transmission efficiency due to the surface plasmon resonance phenomenon. The present invention uses a rectangular hole array pattern (or a dually periodic hole array pattern) to change the transmittance according to the polarization direction of light passing through the filter structure, It is a new concept of active color filter that can apply the method of changing polarized light and adjust the color to be finally filtered.

The present invention also provides an active color filter capable of adjusting the amount of light according to the polarization direction by imparting anisotropy to the hole shape in the metal thin film of the hole array pattern of the square lattice structure, The structure of the display can be simplified. In further detail, the present invention adopts a square array type or a hexagonal type hole array and forms a hole shape in a metal thin film in an anisotropic manner (for example, an elliptical shape or a rectangular shape) The amount of light passing through the filter can be adjusted by the influence of the polarized light. In this case as well, an active color filter can be implemented in which the method of changing the polarized light is finally applied to adjust the gray level of light.

Since the present invention is composed of a combination of a metal thin film and various dielectric materials, the filter structure of the present invention may be used as an electrode. In the device structure compared to the conventional liquid crystal display, the number of polarizers decreases, The structure of the present invention can be simplified, so that the present invention can have a reduction in process steps, process costs, and the like. Also, as the structure of the present invention is simplified, the number of layers through which light passes is reduced, so that the light transmission amount as a whole increases. Therefore, the present invention can reduce the power consumption generated from the white light source (backlight unit).

Since the present invention has the structural characteristic of using a metal thin film, it is possible to reproduce a high transmittance of a nano-sized metal thin film regardless of whether the substrate is warped or not in the processing method. Therefore, the present invention can be used as a part of a flexible display or a transparent display in addition to a flat panel display.

BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the drawings used in the detailed description of the present invention, a brief description of each drawing is provided.
1 is a view (vertical cross-sectional view) showing a structure of a surface plasmonic color filter using a porous metal layer having a hole array of regular hexagonal or square lattice structure, which is compared with the present invention.
Fig. 2 is a view (plan view) illustrating a hole array pattern of a metal layer (porous metal layer) having a square lattice structure included in the surface plasmonic color filter of Fig.
3 is a view (plan view) illustrating an anisotropic hole array pattern of a metal thin film having a rectangular lattice structure according to an embodiment of the present invention.
FIG. 4 is a graph illustrating the transmittance of an active surface plasmonic color filter including a metal thin film having a hole array pattern structure of a rectangular grid shape shown in FIG.
5 is a view (vertical cross-sectional view) illustrating an active surface plasmonic color filter according to an embodiment of the present invention.
6 is a view (plan view) illustrating an anisotropic hole array pattern of a metal thin film including a square lattice structure having an elliptical hole according to another embodiment of the present invention.
FIG. 7 is a graph illustrating the transmittance of an active surface plasmonic color filter having an anisotropic hole array pattern of FIG. 6. FIG.
8 is a view (vertical cross-sectional view) illustrating an active surface plasmonic color filter according to another embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the present invention, and the objects attained by the practice of the invention, reference should be made to the accompanying drawings, which illustrate embodiments of the invention, and to the description in the accompanying drawings.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to embodiments of the present invention with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. Like reference numerals in the drawings denote like elements.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises" or "having", etc., are used to specify that a feature, a number, a step, an operation, an element, a component, or a combination thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and, unless expressly defined herein, are to be construed as either ideal or overly formal Do not.

Before describing the present invention, the comparative example to be compared with the present invention will be described as follows.

1 is a view (vertical cross-sectional view) showing a structure of a surface plasmonic color filter using a porous metal layer having a hole array of regular hexagonal or square lattice structure, which is compared with the present invention.

Referring to FIG. 1, the surface plasmonic color filter shown on the left side of FIG. 1 comprises a substrate, a porous metal layer formed on the substrate, and a dielectric layer. The surface plasmonic color filter shown on the right side of Fig. 1 is composed of a substrate, two dielectric layers formed on the substrate, a porous metal layer formed on two dielectric layers, and two dielectric layers formed on the porous metal layer.

The surface plasmonic color filter of FIG. 1, which is reported as a result of the research, is a hexagonal (or triangular) or square (square) lattice array, and has a hole pattern And a porous metal layer having a repeated shape.

The transmittance characteristic of the surface plasmonic color filter of Fig. 1 is not affected by the polarization characteristics of incident light. This prior art study does not have any particular limitation on the shape of holes such as circular, square, triangular, slit, or elliptical shapes, but all of them are intended to be used for maintaining the transmission of a specific color at a constant level.

The surface plasmonic color filter forms a plurality of nano-sized holes having a predetermined period in the metal thin film to selectively transmit light of a specific wavelength to filter the color. Surface plasmon resonance occurs at the interface between a metal and a dielectric in a nano-sized metal structure. A surface plasmon is a pseudo particle in which free electrons induced in the metal film surface are collectively vibrated by the electric field of the incident light. In the wavelength band where the surface plasmon resonance occurs, the electric field of the incident light and the plasmon are coupled to each other to maximize the amount of light transmitted through the hole, and the amount of the light exceeds the aperture ratio of the hole, thereby increasing the transmittance.

In order to avoid being influenced by the polarization state of light incident from the outside, the shape of the surface plasmonic color filter being announced is the same as that shown in Fig. 2 (for example, in the left-right direction and the vertical direction) A hole array pattern having a period of intervals is formed. The hole array pattern is formed in the porous metal layer of Fig.

Fig. 2 is a view (plan view) illustrating a hole array pattern of a metal layer (porous metal layer) having a square lattice structure included in the surface plasmonic color filter of Fig.

As shown in the right part of FIG. 2, it is assumed that the light travels (inclines) into or out of the ground (above the porous metal layer). An electric field (E Field) oscillating in a constant direction (angle of? = 0 or? ₁ with respect to the horizontal axis) perpendicular to the direction of light propagation indicates the direction of polarization.

The transmittance peak (λsp) caused by the surface plasmon resonance in the structure shown in FIG. 2 is calculated as shown in the following equation (1). The transmittance peak (transmittance peak wavelength) (λsp) can mean the center peak wavelength of transmitted light, that is, the surface plasmon resonance wavelength.

[Equation 1]

Is the dielectric constant of the Equation 1 in, a ₀ is the period of the holes (hole), wherein m and n are arbitrary integers, respectively, ε _m is the metal (metal layer), ε _d is a dielectric material adjacent to the metal (a dielectric layer ).

Referring to Equation (1), when the dielectric constant of the metal and dielectric material is determined and accordingly the period a ₀ of the hole array is adjusted, the transmission band (transmittance peak? Sp) of light passing through the color filter is Can be designed. In this situation, the thickness of the metal film (metal layer) and the dielectric layer, or the shape (shape) and size of the hole are adjusted to optimize the transmittance curve so that the surface plasmonic color filter can be designed to have high transmittance and high color reproducibility. (M, n) = (1, 0) or (m, n) = (1, 2) The transmittance of the light of the longest wavelength band determined by the resonance mode (surface plasmon resonance mode) of the 1st order (first order) calculated by = (0, 1) is the largest. Typically, the plasmonic color filter uses the band as a transmission band.

In such a plasmonic color filter structure, when different kinds of dielectric materials are applied to both sides of the metal, different plasmon resonance modes are generated, and peaks occur in unnecessary wavelength bands in the transmission spectrum. When these two modes are matched, If the same type of dielectric is formed on both sides, the coupling effect between the resonance modes maximizes the plasmon effect and the transmittance can be improved. Therefore, the same type of dielectric must be formed on both sides of the metal. That is, in the case of the active surface plasmonic color filter of the present invention formed (laminated) in the order of the substrate 105, the porous metal layer 110, and the dielectric 1 layer 115 shown in FIG. 5, And the dielectric first layer 115 should adopt the same material or a substance having a similar dielectric constant (or refractive index), and the substrate 205, the dielectric two layer 210, the porous metal layer 215, and the dielectric two layer 220 In the case of the active surface plasmonic color filter of the present invention formed in this order, the dielectric 2 layer 210 and the dielectric 2 layer 220 may be formed of the same dielectric material as each other.

The structure of the surface plasmonic color filter according to the embodiment of the present invention includes a metal thin film having a rectangular hole array formed in a repeated manner with different periods in the longitudinal and transverse directions as shown in FIG. That is, FIG. 3 is a view (plan view) for explaining an anisotropic hole array pattern of a metal thin film having a rectangular lattice structure according to an embodiment of the present invention.

As shown in the right part of FIG. 3, the light travels (inclines) into or out of the ground (onto the metal foil). It is also assumed that a linearly polarized light having an electric field (E Field) oscillating in a certain direction (angle of? = 0 or? ₁ with respect to the horizontal axis) perpendicular to the traveling direction of light is incident on the metal thin film.

In the structure of Fig. 3, the transmission peak? Sp caused by the surface plasmon is calculated as shown in the following equation (2). The transmittance peak (transmittance peak wavelength) (λsp) can mean the center peak wavelength of transmitted light, that is, the surface plasmon resonance wavelength.

&Quot; (2) "

A ₀ is a period in the horizontal direction of the hole (transverse direction or X direction), b ₀ is a period in the vertical direction of the hole (longitudinal direction or Y direction), and m And n are each an arbitrary integer, [epsilon] _m is the dielectric constant of the metal (thin metal film), and [epsilon] _d is the dielectric constant of the dielectric material (dielectric layer) adjacent to the metal.

In Equation (2), m and n are integers, and transmission peaks occur in various wavelength bands depending on combinations of m and n. Unlike the structure of FIG. 2, (m, n) = (1st mode) occurs in two different wavelength bands of (m, n) = (0, 1). The weights are distributed in two modes according to the polarization direction of the electric field (electric field) of the incident light (E field), and the transmittance peak is changed.

FIG. 4 is a graph showing a transmittance change according to polarization of an incident wave in a surface plasmonic color filter including a metal thin film having a rectangular hole array having two different periods as shown in FIG. 3 (graph). 4 is a graph illustrating the transmittance of a surface plasmonic color filter including a metal thin film having a hole array pattern structure of a rectangular grid shape shown in FIG.

Referring to FIG. 4, as the polarization direction changes from 0 degree to 90 degrees, the transmission peak wavelength? Sp is gradually increased from red (red wavelength band) to green (green wavelength band) It can be seen that it moves. Therefore, by using a rectangular hole array pattern (dually periodic hole array or hole array pattern in a rectangular lattice pattern) influenced by the polarization state, it is possible to change the color transmitted through the color filter by adjusting the polarizing direction from the outside The active filtering device can be realized.

5 is a view (vertical cross-sectional view) illustrating an active surface plasmonic color filter according to an embodiment of the present invention.

5, the active surface plasmonic color filter of the display device 100 or the display device 200 may have a structure in which a plurality of nano-sized holes having a predetermined period are formed in a metal thin film, So that the color can be filtered.

The display device (liquid crystal display device) 100 shown on the left side of FIG. 5 includes a substrate 105, a porous metal layer 110, which is a metal thin film, and a dielectric 1 layer 115, A second conductive layer 120, a liquid crystal layer 125, and a first conductive layer 130 that are sequentially disposed (formed or stacked) on the active surface plasmonic color filter, A linear polarizer 135, and a backlight unit 140. In the manufacturing process of the display device 100, the display device 100 includes a substrate (for example, a reflection plate) (not shown), a backlight unit 140, a linear polarizer 135, (Laminated) in the order of the first conductive layer 130, the liquid crystal layer 125, the second conductive layer 120, and the active surface plasmonic color filter, or may be formed in the reverse order.

The substrate 105 may be a transparent flat substrate such as a glass substrate or a flexible substrate such as PET (polyethylene terephthalate) or a plastic substrate (transparent plastic substrate) including PEN (polyethylene naphthalate) ) Substrate. The substrate 105 and the dielectric first layer 115 may be the same material or may each include a material having a similar dielectric constant (or refractive index). The substrate 105 may be a filter substrate.

The metal thin film 110 may include, for example, aluminum (Al), gold (Au), silver (Ag), or copper (Cu). The metal thin film 110 may have a thickness of 10 (nm) to 400 (nm).

The thickness of the dielectric layer 115 may be, for example, 10 (nm) or more and 1000 (nm) or less. Conductive oxides such as dielectric layer 115, for example, include a general dielectric material (dielectric material), such as LiF, or SiO _2, or Al ₂ O _3, MgO, ZnO, ZnS, or ITO (Indium Tin Oxide) (transparent conductive Oxide). ≪ / RTI > The dielectric material of the dielectric layer 115 can fill the inside of the holes of the metal foil 110. [

Each of the first conductive layer 130 and the second conductive layer 120 may include a conductive transparent dielectric material such as ZnO, ITO, ZnS, or WO ₃ (tungsten trioxide).

The active surface plasmonic color filter of the display element 100 includes a substrate 105 and a plurality of apertures formed on the substrate 105 that are periodically disposed and that include a plurality of holes each having a nano- A metal thin film 110 which is a metal layer, and a dielectric first layer 115 which is a first dielectric layer formed on the metal thin film 110.

The holes may be nano holes having a nano-size (a sub-wavelength size of incident light (for example, red light)) and may be arranged two-dimensionally. The shape of each of the holes may be circular, elliptical, rectangular, or triangular, for example, having a sub-wavelength diameter of the incident light. Each of the holes has a size of 50 nm or more and 1 μm or less and an interval between the holes may be 50 nm or more and 1 μm or less .

The holes included in the metal thin film 110 are periodically arranged in a first directional axis and a second directional axis orthogonal to each other so that the color can be adjusted according to the polarization direction of the linearly polarized light provided from the outside, (Period) of the holes arranged in the second direction axis are different from each other. The metal thin film 110 is a metal thin film having a hole pattern in the form of a rectangular array shown in FIG.

The liquid crystal layer 125 of the display device 100 adjusts the polarization direction of the linearly polarized light in response to a voltage (voltage magnitude) applied between the first conductive layer 130 and the second conductive layer 120, And enters the active surface plasmon color filter of the device 100.

The linear polarizer 135 linearly polarizes light (white light) generated from the backlight unit 140 that is the white light and provides the linear polarized light to the liquid crystal layer 125 through the first conductive layer 130. Thus, the active surface plasmon color filter of the display element 100 may be referred to as a voltage driven filter.

The brightness of light generated from the backlight unit 140 can be adjusted so that the display device 100 can express a gray scale (gray scale of light). Therefore, the display device of the present invention can change the color through the active surface plasmon color filter of the display device 100 and can express the gradation by the backlight unit 140.

5 includes a substrate 205, a dielectric 2 layer 210 as a second dielectric layer, a porous metal layer 215 as a thin metal layer, and a dielectric 2 layer 220 as a first dielectric layer. And a second conductive layer 225, a liquid crystal layer 230, and a first conductive layer 235, which are sequentially formed on the active surface plasmonic color filter according to another exemplary embodiment of the present invention, ), A linear polarizer 240, and a backlight unit 245.

The active surface plasmonic color filter of the display element 200 only needs to have an active surface plasma of the display element 100 in that it further includes a second dielectric layer 210 formed between the substrate 205 and the metal film 215. [ A description of the substrate 205, the metal foil 215, and the first dielectric layer 220 included in the active surface plasmonic color filter of the display element 200 is omitted because the display element 100 is different from the monochrome color filter. The description of the substrate 105, the metal foil 110, and the dielectric layer 115 included in the active surface plasmonic color filter of FIG. The dielectric material included in the first dielectric layer 220 and the dielectric material included in the second dielectric layer 210 may be the same. The thickness of the second dielectric layer 210 may be 10 (nm) or more and 1000 (nm) or less. A second dielectric layer 210 may comprise, for example, or include _{Al 2 O 3, MgO, ZnO} , ZnS, or a conductive oxide of a dielectric such as an ITO common dielectric, such as LiF, or SiO _2.

The action (operation) of the second conductive layer 225, the liquid crystal layer 230, the first conductive layer 235, the linear polarizer 240, and the backlight unit 245 included in the display element 200 is performed by the display element The liquid crystal layer 125, the first conductive layer 130, the linear polarizer 135, and the backlight unit 140 included in the liquid crystal display panel 100, Are omitted here.

The active surface plasmonic color filter included in the display device 100 or the display device 200 may be a filter that improves the transmission efficiency of light by utilizing the effect of maximizing the transmittance in a nano-sized hole due to surface plasmon resonance A characteristic in which the transmittance peak wavelength is changed in accordance with the adjusted polarization state (polarization direction) of the incident light by setting different periods in the direction axes repeated in the hole array pattern of the metal thin film repeated in the horizontal and vertical directions Is different from a surface plasmonic color filter in which a conventional transmission color is fixed as a new concept of an active filtering device which can change the filtering color. When a liquid crystal layer is introduced as a method of adjusting the polarization, a polarizing plate in a conventional liquid crystal display device and a dye or pigment-based color filter element can be simplified to a simple structure of the surface plasmonic color filter according to the present invention , The present invention can have advantageous advantages in process procedures, production cost, and design cost.

The embodiment of the present invention shown in Fig. 5 uses a liquid crystal layer 125 or 230 as a method for adjusting polarized light to a voltage. The polarized light from the backlight unit 140 or 245 is linearly polarized in a predetermined direction through the linear polarizer 135 or 240 and then passes through the liquid crystal layer 125 or 230, do. For example, the polarization direction can be adjusted according to a voltage using a liquid crystal mode (a liquid crystal operation mode) such as a TN (twisted nematic) mode or an STN (super twisted nematic) mode. Accordingly, the light passing through the plasmonic color filter having a rectangular hole array changes the transmission curve according to the magnitude of the voltage applied from the outside, and the filtering color is changed. The present embodiment is different from a method of expressing gradation by adjusting the amount of light according to the state of the liquid crystal layer 125 or 230. The state of the liquid crystal layer (or the magnitude of the applied voltage) And can constitute a new concept of active device.

The first conductive layer 130 or 235 and the second conductive layer 120 or 225 should be formed in order to apply a voltage across the liquid crystal layer 125 or 230 shown in FIG. And the second conductive layer 120 or 225 may be made of the same material as the first dielectric layer 115 or the second dielectric layer 220. [ In addition, when the conductive dielectric material (conductive dielectric) is used, the structure can be simplified because the plasmonic color filter structure composed of the dielectric and the metal thin film can serve as the electrode.

In addition, a polarizer layer is omitted in the present invention as compared with the conventional liquid crystal display, and the complicated structure of the color filter using the dye or the pigment can be simplified as the dielectric and the metal thin film, so that the ultimate transmittance of the light of the backlight as a whole can be improved . In order to be able to apply to the display, it is also possible to adjust not only the color but also the brightness of the light, so that the brightness of the backlight unit can be adjusted so that the amount of light can be controlled to express the gradation.

The period of the pattern (the period of the hole) determines the plasmon resonance band, i.e., the position (wavelength band) of the transmission peak. The shape of the hole adjusts the excitation amount of the surface plasmon, (For example, the broadness or sharpness of the transmission peak) of the substrate. The embodiment of the present invention shown in Fig. 5 uses anisotropy of the period of the holes to take advantage of the influence of polarization, and another embodiment of the present invention shown in Fig. 6 uses the polarization effect , Anisotropy of the shape of the hole is used.

6 is a view (plan view) illustrating an anisotropic hole array pattern of a metal thin film including a square lattice structure having an elliptical hole according to another embodiment of the present invention. FIG. 7 is a graph illustrating the transmittance of an active surface plasmonic color filter having an anisotropic hole array pattern of FIG. 6. FIG.

As shown in FIG. 6, when the period a _{0 of} the holes is the same in each direction (direction axis) and an elliptic or rectangular shape in which the hole pattern is anisotropic is used, The amount of surface plasmon matching is controlled according to the polarization direction, and as a result, the amount of light in the transmission band can be controlled. Referring to FIG. 7, it can be seen that as the polarization direction changes from 0 degree to 90 degrees, the light transmission amount decreases at the peak transmittance wavelength. Therefore, the active filtering device of the present invention can be realized which can adjust the amount of light to be filtered by changing the polarization direction.

Korean Patent Laid-Open No. 10-2011-0120718 discloses an example of a surface plasmonic color filter that selectively transmits linearly polarized light. This is because a plurality of slits are arranged in one direction, .

Similar to the embodiment of the present invention described above with reference to FIG. 5, the liquid crystal layer shown in FIG. 8 is used to form a surface plasmonic color The polarization direction of the light incident on the filter can be adjusted.

8 is a view (vertical cross-sectional view) illustrating an active surface plasmonic color filter according to another embodiment of the present invention.

8, the active surface plasmonic color filter of the display device 300 or the display device 400 may be formed by forming a plurality of nano-sized holes having a predetermined period in a metal thin film to selectively transmit light of a specific wavelength So that the color can be filtered.

A display device (liquid crystal display device) 300 shown on the left side of FIG. 8 includes a substrate 305, a porous metal layer 310, which is a metal thin film, and a dielectric 1 layer 315, according to another embodiment of the present invention An active surface plasmonic color filter, and a second conductive layer 320, a liquid crystal layer 325, a first conductive layer 330, a linear polarizer 335, and a backlight (not shown) sequentially formed on the active surface plasmonic color filter. Unit 340 as shown in FIG. In the manufacturing process of the display device 300, the display device 300 includes a substrate (e.g., a reflector) (not shown) of the display device, a backlight unit 340, a linear polarizer 335, 330, a liquid crystal layer 325, a second conductive layer 320, and an active surface plasmonic color filter may be formed (laminated) in this order, or vice versa.

The substrate 305 may be a transparent flat substrate, such as a glass substrate, or a flexible substrate, such as a plastic substrate comprising PET or PEN. The substrate 305 and the dielectric first layer 315 may be the same material or may each include a material having a similar dielectric constant (or index of refraction). The substrate 305 may be a substrate for a filter.

The metal thin film 310 may include, for example, aluminum (Al), gold (Au), silver (Ag), or copper (Cu). The metal thin film 310 may have a thickness of 10 (nm) to 400 (nm).

The thickness of the dielectric layer 315 may be, for example, 10 (nm) or more and 1000 (nm) or less. Dielectric layer 315 may comprise, for example, or a conductive oxide of a dielectric such as Al ₂ O _3, MgO, ZnO, ZnS, or ITO (Indium Tin Oxide) a common dielectric, such as LiF or SiO ₂ . The dielectric material of the dielectric layer 315 can fill the inside of the holes of the metal thin film 310. Each of the first conductive layer 330 and the second conductive layer 320 may include a conductive transparent dielectric material such as ZnO, ITO, ZnS, or WO ₃ . The materials included in the second conductive layer 320 and the materials included in the dielectric layer 315 may be the same.

The active surface plasmonic color filter included in the display device 300 includes a substrate 305 and a plurality of light emitting elements formed on the substrate 305 and adapted to emit light of the linear polarized light according to a polarization direction of linearly polarized light provided (The amount of linearly polarized light is adjusted so that the amount of linearly polarized light is output to the outside of the substrate 305), a plurality of holes, each periodically arranged and each having an nano-sized anisotropic shape, And a first dielectric layer 315 formed on the metal thin film 310. The first dielectric layer 315 is formed on the metal thin film 310. The first dielectric layer 315 is formed on the metal thin film 310, The holes included in the metal thin film 310 are arranged periodically in a first directional axis and a second directional axis perpendicular to each other and are spaced apart from each other by intervals (period) of holes arranged in the first directional axis and The spacing of the holes is the same. That is, holes of anisotropic shape may be formed in a square type array having a constant period in the metal thin film 310, as shown in FIG. In other words, holes of anisotropic shape can be repeatedly arranged with a square unit hole array pattern. The holes may be nano-holes having a nano-size (sub-wavelength size of incident light (for example, red light)), and may be two-dimensionally arranged. Each of the holes has a size of 50 nm or more and 1 μm or less and an interval between the holes may be 50 nm or more and 1 μm or less .

In another embodiment of the metal thin film 310, the holes included in the metal thin film 310 are arranged (formed) in the metal thin film 310 repeatedly with a unit hole array pattern of a regular hexagon It is possible. In the hole array pattern of FIG. 6, the second holes (the hole arrays) from the top are moved to the right and are arranged at a central position between the first holes from above in the shape of a unit array of the regular hexagon Lt; / RTI >

Each of the holes having an anisotropic shape may have an anisotropic shape (shape) having different lengths in the longitudinal direction and the transverse direction, such as the elliptical shape, the rectangular shape, or the hexagonal shape shown in Fig.

The liquid crystal layer 325 of the display device 300 includes the substrate 305 by adjusting the polarization direction of the linearly polarized light in response to a voltage applied between the first conductive layer 330 and the second conductive layer 320 To the active surface plasmon color filter.

The linear polarizer 335 linearly polarizes the light generated from the backlight unit 340, which is the white light, and provides the linear polarized light to the liquid crystal layer 325 through the first conductive layer 330. Thus, the active surface plasmon color filter of the display device 300 may be referred to as a voltage driven filter.

The display device of the present invention can realize color and light gradation through the active surface plasmon color filter of the display device 300.

The display device 400 shown in the right side of FIG. 8 includes a substrate 405, a dielectric 2 layer 410 as a second dielectric layer, a porous metal layer 415 as a metal thin film, and a dielectric 2 layer 420 as a first dielectric layer And a second conductive layer 425, a liquid crystal layer 430, and a first conductive layer 435, which are sequentially formed on the active surface plasmonic color filter, according to another exemplary embodiment of the present invention, ), A linear polarizer plate 440, and a backlight unit 445.

The active surface plasmonic color filter of the display element 400 is only capable of forming the active surface plasmas of the display element 300 in that it further includes a second dielectric layer 410 formed between the substrate 405 and the metal foil 415. [ A description of the substrate 405, the metal foil 415, and the first dielectric layer 420 included in the active surface plasmonic color filter of the display device 400 is omitted because the display device 300 is different from the monochrome color filter. The description of the substrate 305, the metal thin film 310, and the dielectric layer 315 included in the active surface plasmonic color filter of FIG. The dielectric material included in the first dielectric layer 420 and the dielectric material included in the second dielectric layer 410 may be the same. The thickness of the second dielectric layer 410 may be 10 (nm) or more and 1000 (nm) or less. A second dielectric layer 410 may comprise, for example, or include _{Al 2 O 3, MgO, ZnO} , ZnS, or a conductive oxide of a dielectric such as an ITO common dielectric, such as LiF, or SiO _2.

The operation of the second conductive layer 425, the liquid crystal layer 430, the first conductive layer 435, the linear polarizer 440, and the backlight unit 445 included in the display device 400 is the same as the operation The liquid crystal layer 325, the first conductive layer 330, the linear polarizer 335, and the backlight unit 340 included in the liquid crystal display panel 300, Are omitted here.

The active surface plasmonic color filter included in the display device 300 or the display device 400 improves the transmission efficiency by utilizing the effect of maximizing the transmittance in a nano-sized hole due to surface plasmon resonance, The use of a property that the transmittance (transmittance) varies with the polarization state (polarization direction) of light when the hole shape is formed anisotropically in a square or hexagonal hole array pattern Is an active filtering element that can artificially control the intensity of light while maintaining the same color, thereby expressing the gray level of light. When a liquid crystal layer is introduced as a method of adjusting the polarization, a polarizing plate in a conventional liquid crystal display device and a dye or pigment-based color filter element can be simplified to a simple structure of the surface plasmonic color filter according to the present invention , The present invention can have advantageous advantages in process procedures, production cost, and design cost.

The polarization direction of the light transmitted from the backlight unit 340 or 445 is adjusted according to the voltage applied to the liquid crystal layer 325 or 430 and the amount of light to be filtered is adjusted through the surface plasmonic filter layer of the present invention . Therefore, the structure of the color filter and the polarizer, which are disposed on the liquid crystal layer in the conventional structure of the liquid crystal display, can be replaced by only the dielectric and the metal layer of the plasmonic filter.

As described above, the present invention is characterized in that a hole array pattern of a rectangular lattice structure having a period of different sizes in each of the longitudinal direction and the transverse direction is formed in a metal thin film, There is provided an active color filter capable of adjusting the transmittance peak wavelength by using the property that the peak wavelength is affected by the polarization characteristic of the incident light. The present invention also provides an active color filter capable of adjusting the amount of light according to the polarization direction by imparting anisotropy to the hole shape in the array pattern of the square lattice structure included in the metal thin film, The structure of the liquid crystal display can be simplified.

As described above, the embodiments have been disclosed in the drawings and specification. Although specific terms are used herein, they are used for the purpose of describing the present invention only and are not used to limit the scope of the present invention described in the claims or the claims. It is therefore to be understood by those skilled in the art that various modifications and equivalent embodiments may be made without departing from the scope of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

105: substrate
110: Porous metal layer
115: dielectric 1 layer
120: second conductive layer
125: liquid crystal layer
130: first conductive layer
135: Linear polarizer
140: Backlight unit
205: substrate
210: dielectric two-layer
215: Porous metal layer
220: dielectric 2 layer
225: second conductive layer
230: liquid crystal layer
235: first conductive layer
240: Linear polarizer
245: Backlight unit
305: substrate
310: Porous metal layer
315: dielectric 1 layer
320: second conductive layer
325: liquid crystal layer
330: first conductive layer
335: Linear polarizer
340: Backlight unit
405: substrate
410: dielectric 2 layer
415: Porous metal layer
420: dielectric 2 layer
425: second conductive layer
430: liquid crystal layer
435: first conductive layer
440: Linear polarizer
445: Backlight unit

Claims (11)

delete delete In an active surface plasmon color filter,
Board;
And a plurality of holes each having a nano-sized anisotropic shape so as to adjust the intensity of the linearly polarized light according to the polarization direction of the linearly polarized light incident from the outside ; And
And a first dielectric layer formed on the metal thin film,
The holes included in the metal thin film are repeatedly arranged in the form of a regular hexagon unit hole array,
The period between holes of the holes is selected according to the transmission peak (? Sp) of the surface plasmon of the following formula (1)
[Equation 1]

Here, the surface plasmon resonance wavelength is represented by? Sp, which is the center peak wavelength of transmitted light, a ₀ is a period of a hole, m and n are arbitrary integers, and? _M is a dielectric constant of a metal (metal layer) , and _d is the dielectric constant of the dielectric material (dielectric layer) adjacent to the metal. The method of claim 3,
Wherein each of the holes having an anisotropic shape includes a shape having different lengths in the longitudinal direction and the transverse direction, and has an elliptical shape or a hexagonal shape. 4. The active surface plasmon resonator according to claim 3,
And a second dielectric layer formed between the substrate and the metal thin film, wherein the dielectric material included in the first dielectric layer and the dielectric material included in the second dielectric layer are the same. In the display device,
An active surface plasmon resonator comprising a substrate, a metal thin film formed on the substrate, the metal thin film being periodically arranged and having a plurality of holes each having a nano size, and a first dielectric layer formed on the metal thin film, filter;
A liquid crystal layer which adjusts the polarization direction of the linearly polarized light and makes the linearly polarized light enter the active surface plasmon color filter in response to a magnitude of a voltage applied between the first conductive layer and the second conductive layer; And
And a linear polarizer that linearly polarizes light generated from the backlight unit and provides the linear polarized light to the liquid crystal layer,
Holes included in the metal thin film of the active surface plasmon resonance color filter are periodically arranged in a first direction axis and a second direction axis perpendicular to each other so that color adjustment can be performed according to the polarization direction of the linearly polarized light, The spacing of the holes arranged in the directional axis and the spacing of the holes arranged in the second directional axis are selected according to the following equation (2)
&Quot; (2) "

Here, a ₀ is the period a, b ₀ is the period from the second axis of the hole (hole), m and n are arbitrary integers, respectively from the first axis of the holes (hole), ε _m is a metal (Metal thin film), _d is the dielectric constant of the dielectric material (dielectric layer) adjacent to the metal,
Wherein each of the first conductive layer and the second conductive layer comprises a conductive transparent dielectric material,
Wherein brightness of light generated from the backlight unit is adjusted so that the display device can express a gray scale. 7. The active surface plasmon resonator according to claim 6,
And a second dielectric layer formed between the substrate and the metal thin film,
Wherein the dielectric material included in the first dielectric layer and the dielectric material included in the second dielectric layer are the same. delete In the display device,
An active surface plasmon color filter according to any one of claims 3 to 5;
A liquid crystal layer which adjusts the polarization direction of the linearly polarized light and makes the linearly polarized light enter the active surface plasmon color filter in response to a magnitude of a voltage applied between the first conductive layer and the second conductive layer; And
And a linear polarizer that linearly polarizes light generated from the backlight unit and provides the linear polarized light to the liquid crystal layer,
Wherein each of the first conductive layer and the second conductive layer comprises a conductive transparent dielectric material. 10. The active surface plasmon resonator according to claim 9,
And a second dielectric layer formed between the substrate and the metal thin film,
Wherein the dielectric material included in the first dielectric layer and the dielectric material included in the second dielectric layer are the same. 10. The method of claim 9,
Wherein a material contained in the first dielectric layer and a material contained in the second conductive layer are the same.

Images