KR101783133B1

KR101783133B1 - Plasmonic Color Filters With High Color Reproducibility

Info

Publication number: KR101783133B1
Application number: KR1020160030250A
Authority: KR
Inventors: 주병권; 이선욱
Original assignee: 고려대학교 산학협력단
Priority date: 2016-03-14
Filing date: 2016-03-14
Publication date: 2017-09-28
Also published as: KR20170106759A; WO2017160031A1

Abstract

The present invention provides a plasmonic color filter. The plasmonic color filter comprises a red filter formed of a conductor and transmitting red light and the islands being two-dimensionally arranged periodically; A green filter formed of a conductor and arranged to be adjacent to the red filter to transmit green and holes arranged two-dimensionally periodically; And a blue filter formed of a conductor and transmitting blue light and disposed adjacent to the red filter or the green filter and the holes periodically arranged two-dimensionally.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a plasma color filter,

Field of the Invention [0002] The present invention relates to a color filter mounted on a display, a sensor or the like to implement color, and more particularly, to a plasma color filter including an island pattern color filter including periodic islands and an island pattern color filter including periodic islands will be.

The liquid crystal display may comprise a color filter substrate, an array substrate (thin film transistor (TFT) array substrate), and a liquid crystal layer formed between the color filter substrate and the array substrate . Since a manufacturing process of a liquid crystal display device basically requires a number of mask processes, that is, a photolithography process, a method of reducing the number of masks in terms of productivity is required.

The color filter used in the liquid crystal display device absorbs unnecessary color light using dyes or pigments and extinguishes it. The color filter transmits only light of a desired color to realize a color, so that a white light incident on one sub- By transmitting only one of the RGB primary colors, it is difficult for the color filter layer to have a transmittance of 30 (%) or more. For this reason, the transmission efficiency of the panel (LCD panel) is very low, so that the power consumption by the backlight can be increased. In addition, since the color filter repeats color resist application, exposure, development and curing processes for each primary color, the process may be complicated.

As a color filter, a plasmonic color filter (PCF) technique for selectively extracting wavelengths using a scattering phenomenon of light generated in a nanostructure having a periodic pattern has attracted attention. However, among the existing hole pattern plasmonic color filters, the red filter causes serious color interference. Therefore, a color filter having a high color reproducibility of a new structure is required.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a plasmonic color filter which eliminates color interference, increases luminance, and provides high transmittance.

A plasmonic color filter according to an exemplary embodiment of the present invention includes a red filter formed of a conductor and transmitting red light and islands periodically arranged in a two-dimensional manner; A green filter formed of a conductor and arranged to be adjacent to the red filter to transmit green and holes arranged two-dimensionally periodically; And a blue filter formed of a conductor and transmitting blue light and disposed adjacent to the red filter or the green filter and the holes periodically arranged two-dimensionally.

In one embodiment of the present invention, the period of the islands of the red filter may be 270 nm to 370 nm.

In one embodiment of the present invention, the fill factor, which is the ratio of the area occupied by the islands to the total area of the red filter, may be 0.5 to 0.8.

A color filter according to an embodiment of the present invention includes a transparent substrate; And a surface plasmon resonance color filter layer disposed on the same plane on the transparent substrate. Wherein the plasmonic color filter layer comprises a red filter region formed as a conductor and transmitting red light and having islands arranged two-dimensionally periodically; A green filter region formed of the conductor and disposed adjacent to the red filter for transmitting green light and the holes arranged two-dimensionally periodically; And a blue filter region formed of the conductor and permeable to blue and arranged adjacent to the red filter region or the green filter region and the holes periodically arranged two-dimensionally.

In one embodiment of the present invention, the period of the islands of the red filter region may be from 270 nm to 370 nm.

In one embodiment of the present invention, the fill factor, which is the ratio of the area occupied by the islands to the total area of the red filter area, may be 0.5 to 0.8.

In an exemplary embodiment of the present invention, the plasma display device may further include a transparent protective layer that fills spaces and holes between the islands of the plasmonic color filter layer and is laminated on the plasmonic color filter layer.

According to an embodiment of the present invention, the refractive index matching layer may be disposed between the transparent substrate and the plasmonic color filter layer.

In one embodiment of the present invention, the transparent substrate is a glass substrate, and the protective layer may be a dielectric material having an average transmittance of 90% or more in the visible region.

In one embodiment of the present invention, the transparent substrate is a glass substrate, the plasmonic color filter is made of aluminum, has a thickness of 100 nm to 200 nm, the refractive index matching layer has a thickness of 40 nm to 200 nm, The thickness of the protective layer may be 100 nm to 200 nm, and the refractive index matching layer and the protective layer may be LiF.

In one embodiment of the present invention, in the red filter region, the unit lattice of the islands is a square lattice or a triangular lattice, and in the blue filter region and the green filter region, the unit lattice of the holes is a square lattice or a triangular lattice Lt; / RTI >

A liquid crystal display according to an embodiment of the present invention includes a first glass substrate having a thin film transistor layer, a second glass substrate having a color filter layer, and a liquid crystal disposed between the thin film transistor layer and the color filter layer . Wherein the color filter layer comprises a red filter region formed of a conductor and transmitting red light and the islands being two-dimensionally periodically arranged; A green filter region formed of the conductor and disposed adjacent to the red filter for transmitting green light and the holes arranged two-dimensionally periodically; And a blue filter region formed of the conductor and permeable to blue and arranged adjacent to the red filter region or the green filter region and the holes periodically arranged two-dimensionally.

The organic light emitting diode display according to an exemplary embodiment of the present invention includes a lower electrode layer, an organic layer, an upper electrode layer, a protective layer, and a plasmonic color filter layer sequentially stacked on a substrate. Wherein the plasmonic color filter layer comprises a red filter region formed as a conductor and transmitting red light and having islands arranged two-dimensionally periodically; A green filter region formed of the conductor and disposed adjacent to the red filter for transmitting green light and the holes arranged two-dimensionally periodically; And a blue filter region formed of the conductor and permeable to blue and arranged adjacent to the red filter region or the green filter region and the holes periodically arranged two-dimensionally.

The plasmonic color filter according to an embodiment of the present invention includes a first plasmonic color filter formed as a conductor and transmitting first wavelength band and islands periodically arranged in a two-dimensional manner; And a second plasmonic color filter which is formed of the conductor and transmits a second wavelength band different from the first wavelength band and which is arranged adjacent to the first plasmonic color filter and in which the holes are two-dimensionally periodically arranged .

In one embodiment of the present invention, the period of the islands of the first plasmonic color filter may be 270 nm to 370 nm.

In one embodiment of the present invention, the fill factor, which is the ratio of the area occupied by the islands to the total area of the first plasmonic color filter, may be 0.5 to 0.8.

The plasmonic color filter according to an embodiment of the present invention provides a color filter employing a blue or green color filter of a hole array structure and a red filter of a dot array structure. Thus, the three-primary-color plasmonic color filter provides a high-color reproducible color filter and can raise the luminance.

1A is a diagram illustrating a color filter according to an embodiment of the present invention.
1B is a cross-sectional view taken along the line A-A 'in FIG. 1A.
FIG. 2A is a perspective view illustrating a plasmonic color filter of a hole array structure according to an embodiment of the present invention. FIG.
FIG. 2B is a simulation result showing the transmittance according to the wavelength of the plasmonic color filter of the hole array structure of FIG. 2A.
3A is a perspective view illustrating a plasmonic color filter having a dot array structure according to an embodiment of the present invention.
FIG. 3B is a simulation result showing the transmittance according to the wavelength of the plasmonic color filter of the dot array structure of FIG. 3A.
FIG. 4A shows color coordinates according to a grating period P of a plasmonic color filter (D-PCF) of a dot array structure and a plasmonic color filter (H-PCF) of a hole array structure according to an embodiment of the present invention.
FIG. 4B shows the color gamut of a plasmonic color filter combined with R _H G _H B _H and a plasmonic color filter combined with R _D G _H B _H.
4C shows the transmittance characteristic according to the wavelength of the blue plasmonic color filter of the hole array structure.
4D shows the transmittance characteristics according to the wavelength of the green plasmonic color filter of the hole array structure.
4E shows the transmittance characteristics according to the wavelengths of the red plasmonic color filter (R _D ) of the dot array structure and the red plasmonic color filter (R _H ) of the hole array structure.
5A is an electron micrograph of a plasmonic color filter (D-PCF) of a dot array structure and a plasmonic color filter (H-PCF) of a hole array structure according to an embodiment of the present invention.
FIG. 5B shows a plasmonic color filter combined with a color coordinate according to a period of a plasmonic color filter (D-PCF) of a dot array structure and a plasmonic color filter (H-PCF) of a hole array structure and R _H G _H B _H , R _D G _H B _H in the color domain of the plasmonic color filter.
FIG. 5C shows the transmittance according to the wavelength of the blue plasmonic color filter (B _H ) of the hole array structure, the green plasmonic color filter (G _H ) of the hole array structure, and the red plasmonic color filter (R _D ) of the dot array structure .
6A is a diagram illustrating a structure of a plasmonic color filter combined with R _D G _H B _H according to an embodiment of the present invention.
FIG. 6B is a simulation result showing the color coordinates of a plasmonic color filter combined with R _D G _H B _H and a plasmonic color filter combined with R _H G _H B _H.
FIG. 6C is a diagram illustrating a blue color filter (B _H ) of a hole array structure, a green plasmonic color filter (G _H ) of a hole array structure, a red plasma color filter (R _H ) of a hole array structure, And simulation results showing the transmittance characteristics according to the wavelengths of the red plasmonic color filter (R _D ).
7A is a view for explaining a structure of a plasmonic color filter combined with R _D G _H B _H according to an embodiment of the present invention.
FIG. 7B is a simulation result showing the color coordinates of a plasmonic color filter combined with R _D G _H B _H and a plasmonic color filter combined with R _H G _H B _H.
FIG. 7C shows a blue color filter (B _H ) of a hole array structure, a green plasmonic color filter (G _H ) of a hole array structure, a red plasma color filter (R _H ) of a hole array structure, And simulation results showing the transmittance characteristics according to the wavelengths of the red plasmonic color filter (R _D ).
8A is a view for explaining a structure of a plasmonic color filter combined with R _D G _H B _H according to an embodiment of the present invention.
FIG. 8B is a simulation result showing the color coordinates of a plasmonic color filter combined with R _D G _H B _H and a plasmonic color filter combined with R _H G _H B _H.
FIG. 8C shows a blue color filter (B _H ) of a hole array structure, a green plasmonic color filter (G _H ) of a hole array structure, a red plasmonic color filter (R _H ) of a hole array structure, And simulation results showing the transmittance characteristics according to the wavelengths of the red plasmonic color filter (R _D ).
9 is a conceptual diagram illustrating a liquid crystal display device according to another embodiment of the present invention.
10 is a conceptual diagram illustrating an organic light emitting diode display device according to another embodiment of the present invention.

A plasmonic nanostructure in which sub-wavelength holes are arranged two-dimensionally can obtain a uniform optical response from unpolarized incident light. However, in a two-dimensional hole array, because of its geometry, higher order modes of surface plasmon resonance (SPR) are formed, and secondary peaks derived therefrom are formed as main peaks (primary peak) and color interference (color cross-talk).

According to one embodiment of the present invention, we provide a complementary collar that implements pure red-green-blue (RGB) with a combination of a metal hole array and a metal island array (or metal dot array) We propose a filter. Peak-broadening-induced metal island array filters act as optical filters that effectively block wavelengths below 575 nm and extract pure red light. Therefore, the metal island array filter can broaden the color reproducibility without loss of luminance and color tunability. It is expected that the combination of the metal hole array and the metal island array will go beyond the inherent limitations of color reproduction and become competitive as a next generation color filter.

Periodic subwavelength hole arrays can provide extraordinary optical transmission (EOT) by the effect of visible light filtering and coupling of incident light and plasmons. This extraordinary optical transmission has become the basis for the plasmonic color filter to become an important structural color device.

In a typical pigment-based color filter, a single color resist represents only one color. On the other hand, the three primary colors of the plasmonic color filters can be simultaneously fabricated from the same material by adjusting the period of the array. Thus, it has excellent color tunability. Nevertheless, the light efficiency of the plasmonic color filter is still insufficient to replace the pigment-based color filter.

We propose a plasmonic color filter with a combination of hole structure and island structure that can enhance color reproducibility. The plasmonic color filter according to an embodiment of the present invention starts from understanding the chromaticity reduction method of the plasmonic color filter.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in different forms. Rather, the embodiments disclosed herein are provided so that the disclosure can be thorough and complete, and will fully convey the concept of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

Like reference numerals refer to like elements throughout the specification. Accordingly, although the same reference numerals or similar reference numerals are not mentioned or described in the drawings, they may be described with reference to other drawings. Further, even if the reference numerals are not shown, they can be described with reference to other drawings.

1A is a diagram illustrating a color filter according to an embodiment of the present invention.

1B is a cross-sectional view taken along the line A-A 'in FIG. 1A.

1A and 1B, a plasmonic color filter 100 includes a first color filter 126 formed of a conductor and transmitting a first wavelength band and islands 126a arranged two-dimensionally periodically, ; And a second color filter (124) which is formed of the conductor and transmits a second wavelength band different from the first wavelength band and is arranged adjacent to the first color filter (126) and holes arranged two-dimensionally periodically .

The first color filter 126 may include an island pattern layer formed of a conductor and arranged two-dimensionally periodically on the substrate 110, and a dielectric layer disposed on the island pattern layer. The first color filter 126 may be a red color filter.

The second color filter 124 includes a hole pattern layer formed of a conductor and two-dimensionally periodically arranged on the substrate 110 with holes 124a, and a dielectric layer disposed on the hole pattern layer. The second color filter 124 may be a green color filter.

The third color filter 122 includes a hole pattern layer formed of a conductor and two-dimensionally periodically arranged on the substrate 110 with holes 122a and a dielectric layer disposed on the hole pattern layer. The color filter 122 may be a blue color filter.

FIG. 2A is a perspective view illustrating a plasmonic color filter of a hole array structure according to an embodiment of the present invention. FIG.

FIG. 2B is a simulation result showing the transmittance according to the wavelength of the plasmonic color filter of the hole array structure of FIG. 2A.

2A and 2B, a plasmonic color filter 202 having a hole array structure includes a hole array having a hole array stacked on a substrate, a metal layer 222 formed of a metal, and a protective layer of a dielectric material covering the metal layer 232). The plasmonic color filter of the hole array structure may be used as a blue filter or a green filter.

There are two types of spectral distortion that degrade chromaticity of a plasmonic color filter. One is color cross-talk due to multiple transmission peaks. In the visible light region, one transmission peak appears as one color. When two or more peaks are present, another color is created by additive color mixing. The multiple transmission peaks are manifested by the multi-mode of surface plasmon resonance (SPR), which is known to be determined by the geometry of the array. The relationship between the geometrical factor and the center wavelength in a square array is expressed by the following equation.

P is the period of the array, and 竜_m And ε _d Are dielectric constants of the metal layer and the dielectric layer, respectively. i and j are the scattering orders of the two-dimensional array. (

1,0) Let the center wavelength of the ^1st order peak (1 ^st order peak) determined by the resonance mode be λ ₁ , (

One.

1) a center wavelength of the second peak, which is determined by the resonant mode (2 ^nd order peak) Speaking of λ _2,

. Accordingly,? ₂ of the red, green, and blue filters having? ₁ of 620 nm, 530 nm, and 450 nm is 440 nm, 385 nm, and 321 nm, respectively. Unlike green and blue with relatively short wavelengths, a red filter with a first peak at a long wavelength has a second peak with a complete peak shape in the blue visible region.

Referring to FIG. 2B, the transmittance increases as the aperture ratio (area of holes / aperture area, aperture ratio (AR)) of the plasmonic color filter (H-PCF) of the hole array structure increases from 0.1 to 0.5. The period of the hole array is 360 nm. We investigated whether a plasmonic color filter with a hole array structure can operate as a red filter.

The blue light leakage (second peak near 440 nm) of this red filter shifts the color coordinate from red to magenta, and consequently reduces the color reproduction area of the RGB filter. For the same reason, it is known that color cross-talk occurs in a red filter even in a hexagonal array. In the meantime, other researchers have conducted studies to reduce color cross-talk in order to lower the intensity of the secondary peak, or to reduce the intensity of the primary peak (1 ^st order peak) and the secondary peak (2 ^nd order peak) I was able to achieve achievements that increase the distance. But, yet, the second peak (peak 2 ^nd order) by did not completely remove.

Another type of spectral distortion is peak-broadening which causes color degradation. Unlike color cross-talk in which two different colors are mixed, color degradation means that the original color is faded.

Although the extraordinary optical transmission (EOT) has contributed to the improvement of the quantity of light, the plasmonic color filter (H-PCF) of the hole array structure having a small opening spatially divided in the impermeable metal film has an inherently low transmittance There is nothing. If the area of the hole is increased to compensate for the brightness, the function of selectively transmitting the wavelength is weakened and the chromaticity is decreased. This is observed in the form of peak-broadening in which the height and width of the transmission peak increase together.

This peak-broadening has been the solution to the color cross-talk problem mentioned above. That is, the color interference problem can be solved by introducing an island pattern (or a dot pattern) which is an opposite form of the hole pattern. Since the metallic dot reflects light, the reflection spectrum appears as a peak, and the transmission spectrum appears as an inverse-peak. The spectrum transmitting this wide range of wavelengths is not suitable for a transmissive color filter. However, increasing the dot size to induce inverse-peak broadening can result in blocking unwanted light.

According to one embodiment of the present invention, we propose that a dot array-type plasmonic color filter can be used as a red filter.

3A is a perspective view illustrating a plasmonic color filter having a dot array structure according to an embodiment of the present invention.

FIG. 3B is a simulation result showing the transmittance according to the wavelength of the plasmonic color filter of the dot array structure of FIG. 3A.

3B, a plasmonic color filter 206 of a dot array structure includes a metal layer 226 formed of a metal and a dot array 226a stacked on the substrate 110, and a dielectric material covering the metal layer A protective layer 232 may be included. The plasmonic color filter 206 of the dot array structure can be used as a red filter.

The fill factor (FF) of a dot in a rectangular array with a period (P) of 330 nm is defined as a dot area / lattice unit area. When the filter factor (FF) is small, an inverse peak appears in a form in which light of a specific wavelength is partially blocked. When the fill factor (FF) was increased to 0.5 or more, the light of 440 to 505 nm wavelength was completely blocked and the average transmittance of the 380 nm to 575 nm band was reduced to less than 5%. This result implies that an optical filter for extracting pure red light by blocking short wavelengths can be designed through a D-arrayed plasmonic color filter (D-PCF). In conclusion, the red plasmonic color filter of the hole array structure in which color cross-talk occurs is changed to a red plasmonic color filter of a dot array structure. Accordingly, when a red plasmonic color filter of a dot array structure is combined with a blue (B _H ) and a green (G _H ) plasmonic color filter of a hole array structure, an RGB plasmonic color filter of high color can be provided. The period of the plasmonic color filter of the dot array structure may be 270 nm to 370 nm to operate as a red filter and the filter factor may be 0.5 to 0.8.

FIG. 4A shows color coordinates according to a grating period P of a plasmonic color filter (D-PCF) of a dot array structure and a plasmonic color filter (H-PCF) of a hole array structure according to an embodiment of the present invention.

FIG. 4B shows the color gamut of a plasmonic color filter combined with R _H G _H B _H and a plasmonic color filter combined with R _D G _H B _H.

4C shows the transmittance characteristic according to the wavelength of the blue plasmonic color filter of the hole array structure.

4D shows the transmittance characteristics according to the wavelength of the green plasmonic color filter of the hole array structure.

4E shows the transmittance characteristics according to the wavelengths of the red plasmonic color filter (R _D ) of the dot array structure and the red plasmonic color filter (R _H ) of the hole array structure.

Referring to FIG. 4A, in a plasmonic color filter (H-PCF, square) having a hole array structure, the plasma optical color filter (H-PCF) The color coordinates move in the order of blue, green, and red.

The aperture ratio (area of holes / area per lattice) of the plasmonic color filter (H-PCF) of the hole array structure is 0.3. The substrate is a glass substrate. The material of the metal hole pattern and the metal dot pattern is aluminum having a thickness of 130 nm. Further, a 110 nm thick LiF layer is disposed on the metal hole pattern and the metal dot pattern. The metal hole pattern is circular, and the shape of the metal dot pattern is square.

On the other hand, as the period increases from 200 nm to 400 nm at intervals of 10 nm, the color coordinates move in the order of yellow, red, and magenta in a plasmonic color filter (D-PCF, circular) of a dot array structure. In addition, the fill factor (dot area / grid unit area) of the plasmonic color filter of the dot array structure is 0.5. The range of hues that can be expressed by a dot-array plasmonic color filter is limited as compared with a hole-array plasmonic color filter. However, in the case of the red color expression, a plasmonic color filter (D-PCF) of a dot array structure reproduces a red color with higher saturation than a plasmonic color filter (H-PCF) of a hole array structure.

Referring to Figure 4b, a period of 220nm of B _H filter (blue plasmonic color filter of the hole array structure), the period is 300 nm of the G _H filter (of the hole array structure green plasmonic color filters), and, R _H filter (The red color plasmonic color filter of the hole array structure) is 360 nm, and the period of the R _D filter (red color plasmonic color filter of the dot array structure) is 320 nm. R is a red filter, G is a green filter, B is a blue filter, H of a subscript denotes a hole structure, and D of a subscript denotes a dot structure.

In the xy chromaticity coordinate plane, the color reproduction area of the plasmonic color filter combined with R _H G _H B _H is displayed. In addition, a color reproduction area of a plasmonic color filter combined with R _D G _H B _H is displayed.

The maximum color reproduction area of the plasmonic color filter combined with R _H G _H B _H is 35% of the NTSC area as calculated by the area of the triangle. The maximum color reproduction area of the plasmonic color filter combined with R _D G _H B _H is 46% of the NTSC area as calculated by the area of the triangle. The average value of the RGB luminance was 19% in the same manner. That is, the combination of R _D G _H B _H can increase the color reproducibility by 31% without lowering the luminance.

Referring to FIG. 4C, a B _H filter (blue plasmonic color filter of a hole array structure) has a maximum transmission of around 430 nm with a period of 220 nm.

Referring to FIG. 4D, G _H The filter (green plasmonic color filter in a hole array structure) has a maximum transmittance around 550 nm with a period of 300 nm.

Referring to FIG. 4E, secondary peaks of the red plasmonic color filter (R _H ) of the hole array structure were not observed in the red plasmonic color filter (R _D ) of the dot array structure. The average transmittance at wavelengths of 575 nm to 780 nm is 48% in the red plasmonic color filter (R _D ) of the dot array structure and 30% in the red plasmonic color filter (R _H ) of the hole array structure. In addition, the average transmittance at a wavelength of 380 nm to 575 nm is 5.9% in the red plasmonic color filter (R _D ) of the dot array structure and 9.4% in the red plasmonic color filter (R _H ) of the hole array structure. Each of the chromaticity coordinates (x, y) is in the red plasma monik color filter (R _D) of the dot array structure (0.582, 0.395), and in red plasma of the hole array structure monik color filter (R _H), (0.483, 0.330) . Thus, a red plasmonic color filter (R _D ) of a dot array structure provides a higher transmittance in the pass band and a lower transmittance in the cutoff band than the red plasmonic color filter (R _H ) of the hole array structure , And can provide higher chromaticity.

For the transmission spectral simulation, a finite-difference time-domain (FDTD) solution from Liquidal Solutions was used. Both H-PCF and D-PCF were modeled by stacking a 130 nm Al metal film and a 110 nm LiF dielectric film on a glass substrate. The Al metal film of H-PCF was designed as a circular hole and the D-PCF was designed as a square dot. The mesh size of the simulation model is 5 nm and the stair case method is applied. Planar light was used as the light source.

We also simulated hexagonal arrangements, or plasmonic color filters with different materials. In all cases, a plasmonic color filter combined with R _D G _H B _H showed higher performance than a plasmonic color filter combined with R _H G _H B _H in terms of color representation.

5A is an electron micrograph of a plasmonic color filter (D-PCF) of a dot array structure and a plasmonic color filter (H-PCF) of a hole array structure according to an embodiment of the present invention.

FIG. 5B shows a plasmonic color filter combined with a color coordinate according to a period of a plasmonic color filter (D-PCF) of a dot array structure and a plasmonic color filter (H-PCF) of a hole array structure and R _H G _H B _H , R _D G _H B _H in the color domain of the plasmonic color filter.

FIG. 5C shows the transmittance according to the wavelength of the blue plasmonic color filter (B _H ) of the hole array structure, the green plasmonic color filter (G _H ) of the hole array structure, and the red plasmonic color filter (R _D ) of the dot array structure .

Referring to FIG. 5A, we fabricated a plasmonic color filter (D-PCF) of a dot array structure and a plasmonic color filter (H-PCF) of a hole array structure on the same substrate at the same time using the same materials and processes.

A 0.5 mm glass substrate of Corning (Eagle XG glass) was used as the substrate. For the metal hole pattern and the metal dot pattern, an aluminum layer as a metal layer was deposited on the substrate by thermal evaporation deposition. The thickness of the metal layer is 130 nm. Next, an electron-beam resist (trade name: zep-520a, Zeon Chemicals) was coated on the metal layer using a spin coating method.

The hole array and the dot array were simultaneously patterned using electron beam lithography (E-beam lithography). The metal layer was etched using chlorine (Cl ₂ ) based plasma etching equipment. After the metal layer was patterned, the remaining resist was removed using a dedicated stripper. Finally, 110 nm thick LiF was deposited by thermal evaporation on the patterned metal layer.

Plasmonic color filters (H-PCF) with a hole array structure were designed in 17 regions at intervals of 10 nm and 220 nm to 380 nm. Plasmonic color filters (D-PCFs) with a dot array structure were designed in 11 regions with a period of 300 nm to 400 nm at intervals of 10 nm. A total of 28 areas were simultaneously patterned by the electron beam lithography process. The size of one area is 40um x 40um. Like the H-PCF of the hole array structure, the plasmonic color filter (D-PCF) of the dot array structure also displayed a clear color from the non-polarized incident light.

Referring to FIG. 5A, the R _H plasmonic color filter appears magenta and the R _D plasmonic color filter has a high chromaticity red.

Referring to FIG. 5B, the color of the fabricated plasmonic color filter is smaller than that of the simulation result. However, the plasmonic color filter combined with R _D G _H B _H provides a wider color gamut than the plasmonic color filter combined with R _H G _H B _H and can provide a higher chromaticity.

Referring to FIG. 5B, the plasmonic color filter combined with R _H G _H B _H shows a color reproducibility of only 10% with respect to the NTSC region. On the other hand, the plasmonic color filter combined with R _D G _H B _H showed a color reproducibility of 17%.

Referring to FIG. 5C, the maximum transmittance of R _D , G _H , and B _H is about 29 to 40%, and the average luminance is 16%.

Numerous studies have been conducted on nanostructures using hole arrays or dot arrays. However, the plasmonic color filter combined with R _D G _H B _H can provide an RGB color gamut which is difficult to implement conventionally by a combination of other structures. That is, the plasma color filter (H-PCF) having a hole array structure exhibited a wide range of hue, but had a weak point in red representation due to color cross-talk.

On the other hand, a plasmonic color filter (D-PCF) of a dot array structure could not reproduce all three primary colors. However, a plasmonic color filter (D-PCF) of a dot array structure can display a high-luminance red color. Since the plasmonic color filters of two different structures are implemented in the same plane, a plasmonic color filter combined with R _D G _H B _H can retain the existing advantages of color tunability.

6A is a diagram illustrating a structure of a plasmonic color filter combined with R _D G _H B _H according to an embodiment of the present invention.

FIG. 6B is a simulation result showing the color coordinates of a plasmonic color filter combined with R _D G _H B _H and a plasmonic color filter combined with R _H G _H B _H.

FIG. 6C is a diagram illustrating a blue color filter (B _H ) of a hole array structure, a green plasmonic color filter (G _H ) of a hole array structure, a red plasma color filter (R _H ) of a hole array structure, And simulation results showing the transmittance characteristics according to the wavelengths of the red plasmonic color filter (R _D ).

Referring to FIG. 6A, the color filter 300 includes a transparent substrate 110; And a surface plasmon resonance color filter layer 320 disposed on the same plane on the transparent substrate 110.

The plasmonic color filter layer 320 is formed of a conductor and includes a red filter region 326 through which red is transmitted and islands (or dots) 326a are two-dimensionally periodically arranged; A green filter region 324 formed of the conductor and disposed adjacent to the red filter and having holes 324a arranged two-dimensionally periodically; And a blue filter region 322 formed of the conductor and permeable to blue and arranged adjacent to the red filter region or the green filter region and having holes 322a arranged two-dimensionally periodically. The hole array and the dot array are squares in the form of a matrix.

The period of the islands of the red filter region 326 may be from 270 nm to 370 nm. The fill factor, which is the ratio of the area occupied by the islands to the total area of the red filter region 326, may be 0.5 to 0.8.

A transparent protective layer 332 is deposited on the plasmonic color filter layer 320 to fill spaces and holes 322a and 324a between the islands 326a of the plasmonic color filter layer 320. [ The protective layer 332 may be a silicon oxide film or a LiF film. The protective layer may be a dielectric material having an average transmittance of 90 percent or more in the visible region.

The refractive index matching layer 331 may be disposed between the plasmonic color filter layer and the transparent substrate. The refractive index matching layer 331 may be the same as the material of the transparent substrate or the material of the protective layer.

The transparent substrate may be a glass substrate, and the plasmonic color filter may be made of aluminum and may have a thickness of 100 nm to 200 nm. The thickness of the refractive index matching layer is 40 nm to 200 nm, and the refractive index matching layer may be a LiF film. The thickness of the protective layer may be 100 nm to 200 nm, and the protective layer may be a LiF film.

In the red filter region, the unit lattice of the islands may be a square lattice or a triangular lattice (hexagonal lattice structure). In the blue filter region and the green filter region, the unit lattice of the holes may be a square lattice or a triangular lattice.

Referring to FIG. 6B, the color coordinates of a plasmonic color filter (circular) combined with R _D G _H B _H and a plasmonic color filter (square) combined with R _H G _H B _H are displayed. The hole period of R _H is 370 nm, and G _H The hole period of B _H is 220 nm, and the dot period of R _D is 310 nm. The hole diameter of R _H is 229 nm, and G _H Has a hole diameter of 192 nm, a hole diameter of B _H is 136 nm, and a dot diameter of R _D is 210 nm. The color coordinate of R _H is (0.445, 0.279), and G _H (0.328, 0.567), the color coordinates of B _H are (0.164, 0.055), and the color coordinates of R _D are (0.562, 0.378). The mean luminance of the plasmonic color filters combined with R _H G _H B _H is 17.1, The color reproduction area is 33.9% of NTSC. The mean luminance of the plasmonic color filters combined with R _D G _H B _H is 17.3, The color reproduction area is 49.3% of NTSC.

Referring to FIG. 6C, the transmittance of R _D is greater than 0.6 with a maximum at around 650 nm.

7A is a view for explaining a structure of a plasmonic color filter combined with R _D G _H B _H according to an embodiment of the present invention.

FIG. 7B is a simulation result showing the color coordinates of a plasmonic color filter combined with R _D G _H B _H and a plasmonic color filter combined with R _H G _H B _H.

FIG. 7C shows a blue color filter (B _H ) of a hole array structure, a green plasmonic color filter (G _H ) of a hole array structure, a red plasma color filter (R _H ) of a hole array structure, And simulation results showing the transmittance characteristics according to the wavelengths of the red plasmonic color filter (R _D ).

Referring to FIG. 7A, the color filter 400 includes a transparent substrate 110; And a surface plasmon resonance color filter layer 420 disposed on the same plane on the transparent substrate 110.

The plasmonic color filter layer 420 is formed of a conductor and has a red filter region 426 through which red is transmitted and islands (or dots) 426a are two-dimensionally periodically arranged; A green filter region 424 formed with the conductor and disposed adjacent to the red filter and having holes 424a arranged two-dimensionally periodically; And a blue filter region 422 formed of the conductor and permeable to blue and arranged adjacent to the red filter region or the green filter region and having holes 422a arranged two-dimensionally periodically. The hole array and the dot array are squares in the form of a matrix.

The period of the islands of the red filter region 426 may be 270 nm to 370 nm. The fill factor, which is the ratio of the area occupied by the islands to the total area of the red filter region 426, may be 0.5 to 0.8.

A transparent protective layer 432 is deposited on the plasmonic color filter layer 420 to fill spaces and holes 422a and 424a between the islands 426a of the plasmonic color filter layer 420. [ The protective layer 432 may be a silicon oxide film or a LiF film. The protective layer may be a dielectric material having an average transmittance of 90 percent or more in the visible region.

The transparent substrate may be a glass substrate, and the plasmonic color filter may be made of aluminum and may have a thickness of 100 nm to 200 nm. The thickness of the protective layer may be 100 nm to 200 nm, and the protective layer may be a silicon oxide layer. The protective layer may be a dielectric material having an average transmittance of 90 percent or more in the visible region.

Referring to FIG. 7B, chromatic coordinates of a plasmonic color filter (circular) combined with R _D G _H B _H and a plasmonic color filter (square) combined with R _H G _H B _H are displayed. The hole period of R _H is 360 nm, and G _H Is 300 nm, the hole period of B _H is 210 nm, and the dot period of R _D is 320 nm. The hole diameter of R _H is 222 nm, and G _H Has a hole diameter of 185 nm, a hole diameter of B _H is 130 nm, and a dot diameter of R _D is 224 nm. The color coordinate of R _H is (0.465, 0.297) and G _H The color coordinates of B _H are (0.171, 0.083), and the color coordinates of R _D are (0.565, 0.374). The mean luminance of the plasmonic color filters combined with R _H G _H B _H is 20.0, The color reproduction area is 31.5% of NTSC. R _D G _H B _H The mean luminance of the plasmonic color filters combined with the < RTI ID = 0.0 > The color reproduction area is 41.4% of NTSC.

Referring to FIG. 7C, the transmittance of R _D is greater than 0.6 with a maximum at around 650 nm.

8A is a view for explaining a structure of a plasmonic color filter combined with R _D G _H B _H according to an embodiment of the present invention.

FIG. 8B is a simulation result showing the color coordinates of a plasmonic color filter combined with R _D G _H B _H and a plasmonic color filter combined with R _H G _H B _H.

FIG. 8C shows a blue color filter (B _H ) of a hole array structure, a green plasmonic color filter (G _H ) of a hole array structure, a red plasmonic color filter (R _H ) of a hole array structure, And simulation results showing the transmittance characteristics according to the wavelengths of the red plasmonic color filter (R _D ).

Referring to FIG. 8A, the color filter 500 includes a transparent substrate 110; And a surface plasmon resonance color filter layer 520 disposed on the same plane on the transparent substrate 110.

The plasmonic color filter layer 520 is formed of a conductor and has a red filter region 526 through which red is transmitted and islands (or dots) 526a are two-dimensionally periodically arranged; A green filter region 524 formed of the conductor and disposed adjacent to the red filter and having holes 524a arranged two-dimensionally periodically; And a blue filter region 522 formed of the conductor and permeable to blue and arranged adjacent to the red filter region or the green filter region and in which the holes 522a are two-dimensionally periodically arranged. The hole array and the dot array are triangular (hexagonal) in the form of a matrix.

The period of the islands of the red filter region 526 may be from 270 nm to 370 nm. The fill factor, which is the ratio of the area occupied by the islands to the total area of the red filter region 526, may be 0.5 to 0.8.

A transparent protective layer 532 is deposited on the plasmonic color filter layer 520 to fill the spaces and holes 522a and 524a between the islands 526a of the plasmonic color filter layer 520. [ The protective layer 532 may be a silicon oxide film or a LiF film.

In the red filter region, the unit lattice of the islands may be a triangular lattice (hexagonal lattice structure). In the blue filter region and the green filter region, the unit cell of the holes may be a triangular lattice.

Referring to FIG. 8B, a color coordinate of a plasmonic color filter (circle) combined with R _D G _H B _H and a plasmonic color filter (square) combined with R _H G _H B _H is displayed. The hole period of R _H is 440 nm, and G _H The hole period of B _H is 230 nm, and the dot period of R _D is 330 nm. The hole diameter of R _H is 253 nm, and G _H Has a hole diameter of 201 nm, a hole diameter of B _H of 132 nm, and a dot diameter of R _D of 245 nm. The color coordinate of R _H is (0.490, 0.283), G _H (0.365, 0.528), the color coordinates of B _H are (0.162, 0.050), and the color coordinates of R _D are (0.586, 0.394). The mean luminance of the plasmonic color filters combined with R _H G _H B _H was 18.9, The color reproduction area is 34.6% of NTSC. R _D G _H B _H The mean luminance of the plasmonic color filter combined with < RTI ID = 0.0 > The color reproduction area is 42.0% of NTSC.

Referring to FIG. 8C, the transmittance of R _D is greater than 0.6 with a maximum at around 650 nm.

9 is a conceptual diagram illustrating a liquid crystal display device according to another embodiment of the present invention.

9, the liquid crystal display 10 includes a first glass substrate 12 having a thin film transistor layer 13, a second glass substrate 17 having a color filter layer 16, And a liquid crystal (14) disposed between the thin film transistor layer (13) and the color filter layer (16).

The color filter layer 16 includes a red filter region 126 formed of a conductor and transmitting red light and the islands being two-dimensionally periodically arranged; A green filter region 124 formed of the conductor and disposed adjacent to the red filter and having holes arranged two-dimensionally periodically; And a blue filter region 122 formed of the conductor and permeable to blue and arranged adjacent to the red filter region or the green filter region and the holes periodically arranged two-dimensionally.

A first polarizing plate 11 is disposed on the opposite side of the first glass substrate 12 on which the thin film transistor layer 13 is disposed and on the opposite side of the second glass substrate on which the color filter layer 16 is disposed The second polarizing plate 18 may be disposed.

10 is a conceptual diagram illustrating an organic light emitting diode display device according to another embodiment of the present invention.

10, the organic light emitting diode display device 20 includes a lower electrode layer 22, an organic layer 23, an upper electrode layer 24, a protection layer 25, a plasma- And a filter layer (26).

The plasmonic color filter layer 26 comprises a red filter region 126 formed of a conductor and transmitting red light and the islands being two-dimensionally periodically arranged; A green filter region 124 formed of the conductor and disposed adjacent to the red filter and having holes arranged two-dimensionally periodically; And a blue filter region 122 formed of the conductor and permeable to blue and arranged adjacent to the red filter region or the green filter region and the holes periodically arranged two-dimensionally.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood. It is therefore to be understood that the above-described embodiments are illustrative and non-restrictive in every respect.

100: Plasmonic color filter
110: substrate
122: blue filter
124: Green filter
126: Red filter

Claims

A red filter formed as a conductor and transmitting red light and the islands arranged two-dimensionally periodically;
A green filter formed of a conductor and arranged to be adjacent to the red filter to transmit green and holes arranged two-dimensionally periodically;
A blue filter formed of a conductor and transmitting a blue color and arranged adjacent to the red filter or the green filter and the holes arranged two-dimensionally periodically,
Wherein the conductor of the red filter, the conductor of the green filter, and the conductor of the blue filter constitute a plasmonic color filter layer,
Further comprising a transparent protective layer deposited on the plasmonic color filter layer to fill spaces and holes between the islands of the plasmonic color filter layer,
The period of the islands of the red filter is 270 nm to 370 nm,
Wherein a fill factor, which is the ratio of the area occupied by the islands to the total area of the red filter, is 0.5 to 0.8.

The method according to claim 1,
Wherein the plasmonic color filter layer is made of aluminum and has a thickness of 100 nm to 200 nm.

The method according to claim 1,
The thickness of the protective layer is 100 nm to 200 nm,
RTI ID = 0.0 > 1, < / RTI > wherein the protective layer is LiF.

A transparent substrate; And
And a plasmonic color filter layer disposed on the same plane on the transparent substrate,
Wherein the plasmonic color filter layer comprises:
A red filter region formed as a conductor and transmitting red light and the islands being two-dimensionally periodically arranged;
A green filter region formed of the conductor and disposed adjacent to the red filter for transmitting green light and the holes arranged two-dimensionally periodically;
A blue filter region formed of said conductor and permeable to blue and arranged adjacent to said red filter region or said green filter region and holes arranged two-dimensionally periodically,
Further comprising a transparent protective layer deposited on the plasmonic color filter layer to fill spaces and holes between the islands of the plasmonic color filter layer,
The period of the islands of the red filter region is from 270 nm to 370 nm,
Wherein a fill factor, which is a ratio of the area occupied by the islands to the total area of the red filter area, is 0.5 to 0.8.

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5. The method of claim 4,
And a refractive index matching layer disposed between the plasmonic color filter layer and the transparent substrate.

9. The method of claim 8,
Wherein the transparent substrate is a glass substrate,
Wherein the protective layer is a dielectric material having an average transmittance of 90 percent or more in the visible region.

9. The method of claim 8,
Wherein the transparent substrate is a glass substrate,
Wherein the plasmonic color filter layer is made of aluminum and has a thickness of 100 nm to 200 nm,
The thickness of the refractive index matching layer is 40 nm to 200 nm,
The thickness of the protective layer is 100 nm to 200 nm,
Wherein the refractive index matching layer and the protective layer are LiF.

5. The method of claim 4,
In the red filter region, the unit lattice of the islands is a square lattice or a triangular lattice,
Wherein in the blue filter region and the green filter region, the unit lattice of the holes is a square lattice or a triangular lattice.

1. A liquid crystal display comprising a first glass substrate having a thin film transistor layer, a second glass substrate having a plasmonic color filter layer, and a liquid crystal disposed between the thin film transistor layer and the plasmonic color filter layer,
Wherein the plasmonic color filter layer comprises:
A red filter region formed as a conductor and transmitting red light and the islands being two-dimensionally periodically arranged;
A green filter region formed of the conductor and disposed adjacent to the red filter for transmitting green light and the holes arranged two-dimensionally periodically;
A blue filter region formed of said conductor and permeable to blue and arranged adjacent to said red filter region or said green filter region and holes arranged two-dimensionally periodically,
Further comprising a transparent protective layer deposited on the plasmonic color filter layer to fill spaces and holes between the islands of the plasmonic color filter layer,
The period of the islands of the red filter region is from 270 nm to 370 nm,
Wherein a fill factor, which is a ratio of the area occupied by the islands to the total area of the red filter region, is 0.5 to 0.8.

An organic light emitting diode display comprising a lower electrode layer, an organic layer, an upper electrode layer, a protective layer, and a plasmonic color filter layer sequentially stacked on a substrate,
Wherein the plasmonic color filter layer comprises:
A red filter region formed as a conductor and transmitting red light and the islands being two-dimensionally periodically arranged;
A green filter region formed of the conductor and disposed adjacent to the red filter for transmitting green light and the holes arranged two-dimensionally periodically;
A blue filter region formed of said conductor and permeable to blue and arranged adjacent to said red filter region or said green filter region and holes arranged two-dimensionally periodically,
Further comprising a transparent protective layer deposited on the plasmonic color filter layer to fill spaces and holes between the islands of the plasmonic color filter layer,
The period of the islands of the red filter region is from 270 nm to 370 nm,
Wherein a fill factor, which is a ratio of the area occupied by the islands to the total area of the red filter region, is 0.5 to 0.8.

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