KR101557800B1 - Photonic crystal type optical filter reflective type color filter and display device using the same - Google Patents

Abstract

A photonic crystal optical filter, a reflection type color filter using the same, and a display device are disclosed. The disclosed reflective color filter includes a transparent substrate; A barrier layer formed on the transparent substrate and having a plurality of pixel regions; A first material having a relatively high refractive index and a second material having a relatively low refractive index are periodically arranged so as to reflect light in a wavelength band corresponding to a photonic band gap, And a plurality of photonic crystal units of a structure in which an optical cut-off layer is formed on the material.

Description

Technical Field [0001] The present invention relates to a photonic crystal optical filter, a reflective type color filter using the same, and a display device using the same.

The disclosed embodiments relate to a photonic crystal optical filter, a reflective color filter for realizing high color purity, a display device and a manufacturing method thereof.

A pigment dispersion method in which a solution in which a pigment is dispersed in a photoresist is applied to a substrate and a pixel of each color is formed by patterning the solution is used as a method of manufacturing a color filter. Since the pigment dispersion method uses a photolithography process, it can be realized in a large area, is stable not only in terms of thermal and chemical but also in color uniformity. However, since such a pigment type color filter is determined by the absorption spectrum inherent to the pigment in which the color characteristic is dispersed and the light transmittance decreases as the thickness of the color filter becomes thicker, There is a problem that luminance is lowered.

Recently, a photonic crystal type color filter based on a structural color has been studied. The photonic crystal type color filter uses a nanostructure having a size smaller than the wavelength of light to control the reflection or absorption of light incident from the outside, thereby reflecting (or transmitting) light of a desired color, and transmitting (or reflecting) . Such a photonic crystal color filter has a structure in which unit blocks of nano size are periodically arranged at regular intervals. Since the optical characteristics of the photonic crystal type color filter are determined by the size and period of the nanostructure, the wavelength selectivity is excellent and the color bandwidth can be easily controlled by fabricating a structure suitable for a specific wavelength. Due to such characteristics, the photonic crystal type color filter can be more usefully applied to a reflection type liquid crystal display device using external light having a very wide spectrum distribution.

Embodiments of the present invention are to provide a photonic crystal optical filter, a reflective color filter for realizing high color purity, a display device and a manufacturing method thereof.

An optical filter according to an embodiment of the present invention includes a transparent substrate; A barrier layer formed on the transparent substrate; A first material having a relatively high refractive index and a second material having a relatively low refractive index are periodically arranged so as to reflect light of a wavelength band corresponding to a photonic band gap, And a photonic crystal layer having a structure in which a light cut-off layer is formed.

The first material is configured to form island-shaped patterns.

The difference between the real part of the refractive index of the first material and the real part of the refractive index of the second material may be 2 or more and the imaginary part of the refractive index of the first material and the second material may be 0.1 or less in the visible light wavelength band .

An absorbing layer may be further formed on the lower surface of the transparent substrate.

The first material may form an island pattern, and the second material may be a supporting layer supporting an island pattern composed of the first material.

The barrier layer may be made of the same material as the second material.

A reflective color filter according to an embodiment of the present invention includes a transparent substrate; A barrier layer formed on the transparent substrate and having a plurality of pixel regions; A first material having a relatively high refractive index and a second material having a relatively low refractive index are periodically arranged so as to reflect light having a wavelength band corresponding to a photonic band gap, And a plurality of photonic crystal units of a structure in which a light cut-off layer is formed on the first material.

The plurality of photonic crystal units may include: a plurality of red photonic crystal units for reflecting red light; A plurality of green photonic crystal units for reflecting green light; And a plurality of blue photonic crystal units for reflecting blue light.

The plurality of red photonic crystal units, the green photonic crystal units, and the blue photonic crystal units may be arranged in a stripe type, a mosaic type, or a delta type.

The first material is configured to form island-shaped patterns.

The difference between the real part of the refractive index of the first material and the real part of the refractive index of the second material may be 2 or more and the imaginary part of the refractive index of the first material and the second material may be 0.1 or less in the visible light wavelength band .

An absorbing layer may be further formed on the lower surface of the transparent substrate.

The first material may form an island pattern, and the second material may be a supporting layer supporting an island pattern composed of the first material.

The barrier layer may be made of the same material as the second material.

A reflective display device according to an embodiment of the present invention includes a liquid crystal layer in which transmittance to incident light is electrically controlled; A reflection type color filter according to an embodiment of the present invention reflects light of a wavelength band corresponding to a photonic band gap among light incident through the liquid crystal layer. An absorbing layer provided on a lower surface of the transparent substrate; And a TFT-array layer having a plurality of thin film transistors for driving the liquid crystal layer in accordance with image information.

 Each of the plurality of thin film transistors is provided adjacent to each of the plurality of photonic crystal units for each pixel region, and the plurality of thin film transistors and the plurality of photonic crystal units may be provided on the same substrate.

A method of fabricating a reflective color filter according to an embodiment of the present invention includes: forming a barrier layer on a transparent substrate; Wherein a first material having a high refractive index and a second material having a relatively low refractive index are periodically arranged on the barrier layer and the first material forms island patterns and the optical cutoff layer is formed on the first material And forming a photonic crystal layer of the structure.

The optical filter according to the embodiment of the present invention can easily determine the reflection wavelength band by the shape and period of the high-refraction patterns, and is excellent in the filtering performance.

The reflection type color filter according to the embodiment of the present invention has excellent color characteristics and is different from the photolithography process in which the same process is repeated three times in order to realize R, G, B, B can be realized, and the number of processes can be reduced.

The reflective display device according to the embodiment of the present invention can provide a display of excellent quality and can form a reflection type color filter and a TFT array on the same substrate so that manufacturing steps and process errors can be reduced, It is possible.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following drawings, like reference numerals refer to like elements, and the size of each element in the drawings may be exaggerated for clarity and convenience of explanation.

 FIG. 1 is a perspective view showing a schematic structure of an optical filter according to an embodiment of the present invention, and FIG. 2 is a sectional view of the optical filter of FIG. The optical filter 100 includes a transparent substrate 130, a barrier layer 150 formed on the transparent substrate 130, and a photonic crystal layer 160 formed on the barrier layer 150. The absorbing layer 110 may be further provided on the lower portion of the transparent substrate 130.

The photonic crystal layer 160 is provided to reflect light in a wavelength band corresponding to the photonic band gap by a periodic refractive index distribution. The photonic crystal layer 160 has a structure in which a first material 162 having a relatively high refractive index and a second material 166 having a relatively low refractive index are periodically arranged. On the first material 162, A layer 164 is formed.

The first material 162 forms patterns in an island shape. Although shown in the form of a rectangular parallelepiped in the drawing, it is possible to have a circular or polygonal pillar shape, and may have various other shapes. The first material 162 has a larger refractive index than the second material 166. For example, the difference between the refractive index of the first material 162 and the real part of the refractive index of the second material 166 is 2 or more . The imaginary component of the refractive index of the first material 162 and the refractive index of the second material 166 may be 0.1 or less in the visible light wavelength band. If the imaginary component of the refractive index is large, the reflectance becomes low, It is intended to use a substance having a small sub-component value. The single-crystal silicon, poly-silicon as the first material (162) (Poly Si), AlSb, AlAs, AlGaAs, AlGaInP, BP, ZnGeP ₂ which has one may be employed wherein the second material (166) may include Air, PC, PS , PMMA, Si ₃ N ₄ , and SiO ₂ may be employed.

The second material 166 may form a supporting layer that supports an isometric pattern of the first material 162 and may include a region between the patterns formed by the first material 162, And may be formed to cover the entire upper portion of the first material 162. Such a structure can be selected, for example, in order to protect the pattern shape from damage while protecting the first material 162 from being patterned using amorphous silicon and then crystallizing the first material 162 into single crystal silicon or polysilicon .

The optical cutoff layer 164 serves to improve the cut-off characteristics of the optical filter 100. The optical cutoff layer 164 may be formed of a silicon oxide film (SiO2) or a silicon nitride film (Si3N4).

The transparent substrate 130 is provided to serve as a waveguide. Only the light of a specific wavelength is reflected by the crystal structure of the photonic crystal layer 160, and the remaining light is transmitted and confined in the transparent substrate 130. As the transparent substrate 130, a glass substrate may be used.

The barrier layer 150 is provided between the transparent substrate 130 and the photonic crystal layer 160. The barrier layer 150 may be formed by doping an impurity in the glass substrate used as the transparent substrate 130 during the crystallization process into a silicon material used as the first material 162 of the photonic crystal layer 160, So as to prevent the purity from lowering. The barrier layer 150 may be made of a material having a refractive index similar to the refractive index of the transparent substrate 130. As the material of the barrier layer 150, a material such as a material selected from the second material 166 forming the supporting layer may be used.

The absorbing layer 110 may be further provided on the lower portion of the transparent substrate 130. The absorption layer 110 can improve the reflectance characteristic of the optical filter 100 by absorbing light confined in the transparent substrate 130.

The optical filter 100 having the above-described structure reflects light of a specific wavelength band by a photonic cystal structure forming a periodic refractive index distribution. In this case, since the band width and the width are determined by the shape and the period of the patterns formed by the first material 162, it is easy to select them appropriately and the filtering performance is excellent, so that the present invention can be applied to various technical fields. For example, it can be applied to a solar cell, a QD-LED, an OLED, and can also be applied to a color filter of a display device, as described below.

3 is a cross-sectional view showing a schematic structure of a reflection type color filter according to an embodiment of the present invention. The reflective color filter 200 includes a transparent substrate 230, a barrier layer 250 formed on the transparent substrate 230, and a plurality of photonic crystals 250 that reflect light of a predetermined wavelength band formed on the barrier layer 250. [ Units 270, 280, and 290.

The area on the barrier layer 250 is made up of a plurality of pixel areas PA1, PA2 and PA3. For example, the red pixel _R , which reflects the red light L _R of the incident light L, The unit 270 includes a green photonic crystal unit 280 for reflecting the green light L _G and a blue photonic crystal unit 290 for reflecting the blue light L _{B in the} pixel area PA3 do. The red photonic crystal unit 270, the green photonic crystal unit 280 and the blue photonic crystal unit 290 are formed of a first material 272 (282) 292 having a relatively high refractive index and a second material 272 Off layers 274, 286 and 296 are arranged on the first materials 272, 282 and 292, respectively. The first materials 272, 282, and 292 form patterns in an island shape.

The first material 272, 282, 292, the second material 276, 286, 296 in the red photonic crystal unit 270, the green photonic crystal unit 280 and the blue photonic crystal unit 290, The material of the first material 162, the second material 166 and the optical cutoff layer 164 of the optical filter 100 of FIG. 1 may be selected from various materials have. In addition, the photonic crystals may be selected from different materials or the same materials in different photonic crystal units, and photonic materials having the pattern shapes and the cycles formed by the first materials 272, 282, and 292 may be red, green, Are set differently to have a bandgap. For example, the pattern size formed by the first material 272 of the red photonic crystal unit 270 may be a pattern formed by the first material 282 of the green photonic crystal unit 280, The pattern formed by the material 292 is larger in size and cycle. The pattern formed by the first material 282 of the green photonic crystal unit 280 is larger in size and period than the pattern formed by the first material 292 of the blue photonic crystal unit 290.

The absorbing layer 210 may be further formed on the lower surface of the transparent substrate 230. The absorption layer 210 absorbs the light confined in the transparent substrate 230. That is, since light of a color not reflected by each of the red photonic crystal unit 270, the green photonic crystal unit 280 and the blue photonic crystal unit 290 is confined in the transparent substrate 230 and absorbed by the absorption layer 210, 200 have higher color purity.

In the drawing, only three photonic crystal units 270, 280, and 290 constituting basic pixels are shown as an example, but the reflective color filter 200 has a structure in which a plurality of photonic crystal units 270, 280, and 290 constituting basic pixels are repeatedly arranged.

4A to 4C show various embodiments of the arrangement structure of the plurality of photonic crystal units 270, 280, and 290 of the reflective color filter 200 of FIG. 4A shows a plurality of red photonic crystal units 270 arranged in rows and a plurality of green photocrystal units 280 and a plurality of blue photocrystal units 290 arranged in stripes. 4B shows a mosaic arrangement in which a plurality of red photonic crystal units 270, a green photonic crystal unit 280 and a blue photonic crystal unit 290 are arranged such that photonic crystal units of different colors are adjacent to each other. 4C shows a plurality of red, green, and blue photonic crystal units 270 (FIG. 4C) so that the centers of the red photonic crystal unit 270, the green photonic crystal unit 280, and the blue photonic crystal unit 290 are connected in a delta 280) < / RTI > Although not shown in detail in the drawings, the size and period of the patterns formed by the red photonic crystal unit 270, the green photonic crystal unit 280, and the blue photonic crystal unit 290 are respectively referred to as photonic band gaps corresponding to red, Respectively. For example, the size and cycle of the red photonic crystal unit 270 pattern are the largest, and the size and cycle of the blue photonic crystal unit 290 pattern are the smallest.

5 is a cross-sectional view showing a schematic structure of a display device according to an embodiment of the present invention. Referring to FIG. 1, a display device 300 includes a liquid crystal layer 330 having an optically controlled transmittance to incident light, and a reflective layer 330 that reflects light in a wavelength band corresponding to a photonic band gap of light incident through the liquid crystal layer 330 And a TFT-array layer 310 having a plurality of thin film transistors 312 for driving the liquid crystal layer 330 in accordance with image information.

The reflective color filter 200 has substantially the same structure as the reflective color filter 200 described with reference to FIG. 3, and thus a detailed description thereof will be omitted.

The TFT-array layer 310 includes a plurality of thin film transistors 312 and a plurality of pixel electrodes 314. In this embodiment, a plurality of thin film transistors 312 for driving the liquid crystal layer 330 corresponding to the individual pixels are provided for each of the pixel regions PA1, PA2, and PA3 in a plurality of photonic crystal units 270, 280, As shown in Fig. That is, the thin film transistor 312 and the photonic crystal unit 270 (280, 290) are formed on the same substrate.

The liquid crystal layer 330 is provided between the two transparent substrates 230 and 360 because the transmittance of incident light is changed according to the electrical control. The alignment layers 340 and 320 are provided on the upper and lower sides of the liquid crystal layer 330, respectively. As the liquid crystal layer 330, various kinds of liquid crystal well-known to those skilled in the art can be employed. For example, twisted nematic (TN) liquid crystal, mixed-mode TN liquid crystal, polymer dispersed liquid crystal (PDLC), Heilmeier-Zanoni liquid crystal, CK (Cole-Kashnow) liquid crystal and the like can be employed.

A transparent electrode 350 is provided on one surface of the upper transparent substrate 360 facing the liquid crystal layer 330 and a polarizing plate 370 is provided on the other surface. The polarizing plate 370 may not be required depending on the specific type of the liquid crystal layer 330 and the driving mode or a polarizing plate or a quarter wave plate having a polarization axis perpendicular to the polarization axis of the polarizing plate 370 may be further provided.

The display device 300 of the embodiment of the present invention has a structure in which the photonic crystal units 270, 280 and 290 of the reflective color filter 200 and the thin film transistor 312 are formed on the same substrate, -Array layer 310 can be fabricated in the same process step. Such a structure has various manufacturing advantages as compared with the general liquid crystal display device in which the color filter is provided on the upper substrate and the TFT array is provided on the lower substrate. For example, when a color filter and a TFT array are fabricated separately, the color filter and the TFT array must be connected in line by pixel, and an alignment error may occur. In this embodiment, Since the TFT array is provided, this error can be reduced.

Although the thin film transistor 312 and the photonic crystal units 270, 280 and 290 are formed on the same substrate in this embodiment, the present invention is not limited thereto. Unlike what is shown, the reflective color filter 200 and the TFT-array layer 310 may be formed as separate layers.

6A to 6K are views for explaining a manufacturing method of a reflective color filter according to an embodiment of the present invention.

A method of fabricating a reflective color filter according to an embodiment of the present invention includes: forming a barrier layer on a transparent substrate; Wherein a first material having a high refractive index and a second material having a relatively low refractive index are periodically arranged on the barrier layer and the first material forms island patterns and the optical cutoff layer is formed on the first material Forming a photonic crystal layer of the structure; And forming an absorbing layer below the transparent substrate.

The above processes will be described in more detail as follows.

First, referring to FIG. 6A, a barrier layer 450 and a silicon layer 462 corresponding to the first material are sequentially formed on a transparent substrate 430.

As the transparent substrate 430, for example, a glass substrate can be used.

The silicon layer 462 is selected in that the silicon material has a large real refractive index and a small imaginary refractive index. This property is especially provided for monocrystalline silicon or polysilicon (poly Si). The silicon layer 462 may be formed of amorphous silicon, which is subjected to a recrystallization step, as described below.

The barrier layer 450 is proposed because it is difficult to directly form a single crystal silicon thin film on a glass substrate. That is, impurities of the glass substrate employed as the transparent substrate 430 in the crystallization step to be described later may be embedded in the silicon layer 462 to lower crystal purity, and the barrier layer 450 serves to prevent this phenomenon . The barrier layer 450 also acts as an etch stop when etching the silicon layer 462, thereby reducing process errors such as under-trenching. The barrier layer 450 may be formed of a material such as PC, PS, PMMA, Si ₃ N ₄ , or SiO _2, and may be formed of a material having a small difference in refractive index from the transparent substrate 430.

Next, a hard mask layer 464 is formed on the silicon layer 462 as shown in FIG. 6B. The hard mask layer 464 serves as a hard mask for etching when patterning the silicon layer 462 and is also provided to ensure etching selectivity. As the material of the hard mask layer 464, a silicon oxide film (SiO 2) or a silicon nitride film (Si 3 N 4) may be employed. A part of the hard mask layer 464 remains after the patterning of the silicon layer 462 and the silicon oxide film (SiO2) or the silicon nitride film (Si3N4) has a lower refractive index than that of the silicon material, It plays a role of improving.

Next, to form a resist pattern, a resin layer 465 'is formed on the hard mask layer 464 as shown in FIG. 6C. As the material of the resin layer 465 ', for example, an ultraviolet ray curable resin may be employed.

Next, the mold M is prepared as shown in FIG. 6D. The mold M is prepared for the nanoimprint process and the specific shape is made to correspond to the pattern of the island shape to be formed by the silicon layer 462. [ For example, it can have any one of the pixel arrays described in Figs. 4A to 4C, and has a different pattern and period corresponding to each color.

Next, as shown in FIG. 6E, the mold M is placed on the resin layer 465 'and irradiated with ultraviolet rays (UV). Then, the mold M is separated as shown in FIG. 6F to form a resist pattern 465.

6G, the hard mask layer 464 is etched using the resist pattern 465 as a mask so that the silicon layer 462 is exposed.

6H, the silicon layer 462 is etched to expose the barrier layer 450 using the resist pattern 465 and the hard mask layer 464 as a mask. The silicon layer 462 forms island-shaped patterns as shown.

The patterning of the silicon layer 462 is performed by the nanoimprint process as described above. In this case, the shape of the pixel array can be selected without restriction as compared with the case of using the photolithography process. For example, among the various pixel arrays illustrated in FIGS. 4A to 4C, the delta type array has the best color mixing characteristic and the driving circuit is simple, but it is known that it is difficult to apply it using the photolithography process. In the case of using the nanoimprint process, there is almost no difference in process according to the pixel array type, and it is easy to apply to the delta type array.

Next, as shown in FIG. 6I, a supporting layer 466 filling between the island-shaped patterns may be further formed. The support layer 466 may be in the form of covering the entirety of the silicon layer 462 and between the island-shaped patterns, as shown.

Next, a step of recrystallizing the silicon layer 462 is performed as shown in FIG. 6J. An excimer laser (EL) is applied to the silicon layer 462 for crystallization. In this excimer laser annealing process, the silicon layer 462 may melt and change shape, and the supporting layer 466 protects the silicon layer 462 to reduce such a shape change.

FIG. 6K shows a case where the scan direction is parallel to the array direction of the patterns formed by the silicon layer 462 (flat leading end method) when the excimer laser is irradiated. FIG. (Tapered leading end method). In the drawings, the arrow direction indicates the scan direction. As shown in FIGS. 6K and 61, the crystallization of the silicon layer 462 made of amorphous silicon is caused by the excimer laser irradiation to change into the crystalline silicon layer 463. In the tapered leading end method of FIG. 61, It is possible to nucleate the amorphous semiconductor layer and crystallize easily.

Through the above-described processes, the reflective color filter 400 having the same structure as that of FIG. 6M is manufactured.

Although the step of forming the absorbing layer at the bottom of the transparent substrate 430 is omitted in the above explanation, it may include the step of further providing an absorbing layer at the lower surface of the transparent substrate 430. For example, It is possible to perform the processes described in the transparent substrate 430 formed on the bottom surface.

The optical filter, the reflective color filter, the display device, and the method of manufacturing the same according to the present invention have been described with reference to the embodiments shown in the drawings to facilitate understanding of the present invention. However, those skilled in the art It will be understood that various modifications and equivalent embodiments are possible. Accordingly, the true scope of the present invention should be determined by the appended claims.

1 is a perspective view showing a schematic structure of an optical filter according to an embodiment of the present invention.

2 is a cross-sectional view of the optical filter of Fig.

3 is a cross-sectional view showing a schematic structure of a reflection type color filter according to an embodiment of the present invention.

Figs. 4A to 4C show various embodiments of the arrangement structure of a plurality of photonic crystal units of the reflective color filter of Fig.

5 is a cross-sectional view showing a schematic structure of a display device according to an embodiment of the present invention.

6A to 6M are views for explaining a method of manufacturing a reflective color filter according to an embodiment of the present invention.

Description of the Related Art

100 ... optical filter 110, 210 ... absorbing layer

130, 230, 360, and 460, a transparent substrate 150, 250,

The photonic crystal units 162, 272, 282, 292,

   164,274,284,294,464 ... optical cut-off layer 166,276,286,296 ... second material

   200 ... reflective color filter 300 ... display device

  310 ... TFT-array layer 312 ... thin film transistor

   314 ... pixel electrode 320, 340 ... alignment layer

   330 ... liquid crystal layer 350 ... transparent electrode

   370 ... polarizer 462 ... silicon layer

   463 ... crystalline silicon layer 465 '... resin layer

   465 ... resist pattern 466 ... supporting layer

Claims (29)

A transparent substrate; A barrier layer formed on the transparent substrate; Wherein the first material and the second material are periodically arranged so as to reflect light in a wavelength band corresponding to a photonic band gap, the first material having a larger refractive index than the second material, And a photonic crystal layer having a structure in which an optical cut-off layer is formed on the first material. The method according to claim 1, Wherein the first material forms a plurality of island-shaped patterns spaced apart from each other. The method according to claim 1, And the difference between the real part component of the refractive index of the first material and that of the second material is 2 or more. The method according to claim 1, Wherein an imaginary component of a refractive index of the first material and the second material is 0.1 or less in a visible light wavelength band. The method according to claim 1, Wherein the _{first material} is any one of single crystal Si, Poly Si, AlSb, AlAs, AlGaAs, AlGaInP, BP, and ZnGeP2. The method according to claim 1, Wherein the second material is any one of Air, PC, PS, PMMA, Si ₃ N ₄ and SiO ₂ . The method according to claim 1, Wherein the optical cut-off layer comprises a silicon oxide film (SiO2) or a silicon nitride film (Si3N4). 8. The method according to any one of claims 1 to 7, Wherein an absorption layer is formed on a lower surface of the transparent substrate. 8. The method according to any one of claims 1 to 7, Wherein the first material comprises a plurality of island patterns spaced apart from each other, Wherein the second material forms a supporting layer for supporting an island-like pattern made of the first material. 10. The method of claim 9, Wherein the barrier layer is made of the same material as the second material. A transparent substrate; A barrier layer formed on the transparent substrate and having a plurality of pixel regions; A first material and a second material are periodically arranged in the plurality of pixel regions so as to reflect light in a wavelength band corresponding to a photonic band gap, and the first material has a refractive index larger than that of the second material And a plurality of photonic crystal units having a structure in which an optical cut-off layer is formed on the first material. 12. The method of claim 11, The plurality of photonic crystal units may include: A plurality of red photonic crystal units for reflecting red light; A plurality of green photonic crystal units for reflecting green light; And a plurality of blue photonic crystal units for reflecting blue light. 13. The method of claim 12, Wherein the plurality of red photonic crystal units, green photonic crystal units, and blue photonic crystal units are arranged in stripe, mosaic, or delta shapes. 12. The method of claim 11, Wherein the first material forms a plurality of island-shaped patterns spaced apart from each other. 12. The method of claim 11, Wherein a difference between the first sub-component and the second sub-component of the refractive index of the second substance is 2 or more. 12. The method of claim 11, Wherein the imaginary component of the refractive index of the first material and the second material is 0.1 or less in the visible light wavelength band. 12. The method of claim 11, The first material is a single crystal Si, Poly Si, AlSb, AlAs , AlGaAs, AlGaInP, BP, ZnGeP 2 any one of the reflection type color filter. 12. The method of claim 11, Wherein the second material is any one of Air, PC, PS, PMMA, Si ₃ N ₄ , and SiO ₂ . 12. The method of claim 11, Wherein the optical cut-off layer comprises a silicon oxide film (SiO2) or a silicon nitride film (Si3N4). 20. The method according to any one of claims 11 to 19, And an absorption layer is formed on the lower surface of the transparent substrate. 20. The method according to any one of claims 11 to 19, The first material forms island-shaped patterns, Wherein the second material forms a supporting layer for supporting island-like patterns made of the first material. 22. The method of claim 21, Wherein the barrier layer is made of the same material as the second material. A liquid crystal layer in which transmittance to incident light is electrically controlled; Wherein the reflective color filter of claim 21 reflects light of a wavelength band corresponding to a photonic band gap of light incident through the liquid crystal layer. An absorbing layer provided on a lower surface of the transparent substrate; And a TFT-array layer having a plurality of thin film transistors for driving the liquid crystal layer in accordance with image information. 24. The method of claim 23, Wherein each of the plurality of thin film transistors is provided adjacent to each of the plurality of photonic crystal units for each pixel region, Wherein the plurality of thin film transistors and the plurality of photonic crystal units are provided on the same substrate. Forming a barrier layer on the transparent substrate; Wherein a first material and a second material are periodically arranged on the barrier layer, the first material has a larger refractive index than the second material, and the first material forms a plurality of island patterns spaced apart from each other And forming a photonic crystal layer having a structure in which an optical cut-off layer is formed on the first material. 26. The method of claim 25, Wherein forming the photonic crystal layer comprises: Sequentially forming a silicon layer corresponding to the first material and a hard mask layer to be the optical cutoff layer on the barrier layer; Forming a resist pattern corresponding to the island-shaped patterns on the hard mask layer by an imprint process; Etching the hard mask layer using the resist pattern as a mask; Etching the silicon layer to expose the barrier layer using the resist pattern and the hard mask layer as a mask; And crystallizing the silicon layer. 27. The method of claim 26, Before the crystallization step, And further forming a supporting layer for filling between the island-shaped patterns. 28. The method of claim 26 or 27, Wherein the crystallization step comprises: A method of manufacturing a reflective color filter, which is performed by an excimer laser annealing process. 29. The method of claim 28, Wherein the scan direction when irradiated with the excimer laser has an angle of 45 degrees with respect to the arrangement direction of the island-shaped patterns.

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