KR101640818B1 - Polarizing color filter using surface plasmon and liquid crystal display device having the same - Google Patents

Abstract

A polarizing color filter, a liquid crystal display, and a method of manufacturing the same using a surface plasmon of the present invention form a transmissive film pattern composed of a plurality of sub-wavelength holes having a periodicity in a metal film By selectively transmitting only a specific wavelength of light using a surface plasmon phenomenon, the transmittance of the panel can be improved by realizing a desired color, and a slit-shaped hole having a very large aspect ratio can be applied to linearly polarize the transmitted light, And the like.
Particularly, the polarizing color filter and the liquid crystal display using the surface plasmon of the present invention, and the method of manufacturing the same, can form a plurality of slit-shaped grooves having periodicity in a region surrounding the plurality of slit- It is possible to improve the viewing angle dependency of the center peak wavelength of the transmitted light and improve the transmittance and the light condensing property simultaneously by forming a beam shape having a narrow divergence angle.
In addition, the polarizing color filter and the liquid crystal display using the surface plasmon according to the present invention and the method of manufacturing the same can be realized by providing a reflector having a one-dimensional lattice arrangement under a backlight light source to reflect incident light of a specific wavelength band, Or the incident light of the S polarized light component is converted into the P polarized light and re-entered, whereby the backlight can be recycled.

Description

TECHNICAL FIELD [0001] The present invention relates to a polarizing color filter using a surface plasmon, and a liquid crystal display device having the polarizing color filter. [0002]

The present invention relates to a polarizing color filter using a surface plasmon and a liquid crystal display having the same, and more particularly to a polarizing color filter using a surface plasmon having a slit-shaped transmission film pattern selectively transmitting only light of a specific wavelength, To a liquid crystal display device.

Recently, interest in information display has increased, and a demand for using portable information media has increased, and a light-weight flat panel display (FPD) that replaces a cathode ray tube (CRT) And research and commercialization are being carried out. Particularly, among such flat panel display devices, a liquid crystal display (LCD) is an apparatus for displaying an image using the optical anisotropy of a liquid crystal, and is excellent in resolution, color display and picture quality and is actively applied to a notebook or a desktop monitor have.

The liquid crystal display comprises a color filter substrate, an array substrate, and a liquid crystal layer formed between the color filter substrate and the array substrate.

Since the manufacturing process of the 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.

Hereinafter, the structure of a typical liquid crystal display device will be described in detail with reference to FIG.

1 is an exploded perspective view schematically showing a general liquid crystal display device.

As shown in the figure, the liquid crystal display comprises a color filter substrate 5, an array substrate 10, and a liquid crystal layer (not shown) formed between the color filter substrate 5 and the array substrate 10 30).

The color filter substrate 5 is a color filter substrate composed of a plurality of sub-pixels 7 that implement the colors of red (R), green (G) and blue (B) A black matrix 6 for separating the filter C and the sub-color filter 7 from each other and shielding light transmitted through the liquid crystal layer 30, and a black matrix 6 for applying a voltage to the liquid crystal layer 30 And a transparent common electrode (8).

The array substrate 10 includes a plurality of gate lines 16 and data lines 17 arranged vertically and horizontally to define a plurality of pixel regions P and a plurality of gate lines 16 and data lines 17, A thin film transistor (TFT) T which is a switching device formed in the intersection region and a pixel electrode 18 formed on the pixel region P.

The color filter substrate 5 and the array substrate 10 constituted as described above are adhered to each other so as to oppose each other by a sealant (not shown) formed on the periphery of the image display area to constitute a liquid crystal display panel, 5 and the array substrate 10 are bonded together through a cemented key (not shown) formed on the color filter substrate 5 or the array substrate 10.

At this time, in order to prevent the defects of the light leakage due to the alignment error during the cementation, an alignment margin is secured by enlarging the line width of the black matrix, thereby decreasing the aperture ratio of the panel.

Conventional color filters used in the liquid crystal display use only dyes or pigments to absorb and dissipate unnecessary color light and transmit only the color light to be realized, By transmitting only one of the RGB three primary colors in white light, the transmittance is not more than 30%. For this reason, the transmission efficiency of the panel is so low that the power consumption by the backlight is increased.

Fig. 2 is an exemplary diagram schematically showing the transmission efficiency of a panel when a color filter using a general pigment dispersion method is used.

Referring to FIG. 5, it can be seen that the light incident from the backlight is reduced in light amount through the polarizer, the TFT array, the liquid crystal, and the color filter, thereby reducing the transmission efficiency to less than 5%.

In this case, the polarizing plate, the TFT array, and the color filter each have a transmittance of 40%, 45% to 55%, and 25%, respectively.

Particularly, when the above color filter is applied to a liquid crystal display device, linearly polarized light is used to obtain a high contrast ratio. In order to make linearly polarized light from a non-polarized backlight source, Two aligned linear prisms are used so that more than 40% of the incident light is lost due to the arrangement of the polarizers. That is, since the liquid crystal display device is basically not a self-luminous element, a backlight unit which is a separate light source is required. At this time, the amount of light transmitted through the movement of the liquid crystal molecules according to the applied signal voltage is adjusted. In order to prevent the transmitted light from being interfered with or canceled, a polarizing plate which passes only linearly polarized light as a component is necessarily required. In this way, the polarizing plate transmits light polarized in one direction and absorbs polarized light in the other direction. In this case, since about 45% of the unpolarized incident light is absorbed, there has been a problem of lowering the luminance of the liquid crystal display device.

In addition, since the conventional color filter must repeat the color resist coating, exposure, development and curing processes for each primary color, the process is complicated. In order to manufacture a color filter on a color filter substrate, a color filter process Line investment, which leads to an increase in line investment costs.

Disclosure of the Invention The present invention has been made to solve the above problems, and it is an object of the present invention to provide a color filter having improved transmission efficiency by using surface plasmon phenomenon without using a conventional dye or pigment, A color filter, and a liquid crystal display device having the same.

Another object of the present invention is to provide a polarizing color filter using a surface plasmon which improves the viewing angle dependence of the center peak wavelength and improves the transmittance and the light condensing property, and a liquid crystal display device having the polarizing color filter.

Another object of the present invention is to provide a liquid crystal display device in which the color filter is used as a polarizer and simultaneously used as a common electrode or rear ITO, or formed with a switching element on a lower array substrate, thereby simplifying the process and reducing investment cost .

It is another object of the present invention to provide a liquid crystal display device capable of reusing a backlight source.

Other objects and features of the present invention will be described in the following description of the invention and claims.

In order to achieve the above object, the polarizing color filter using the surface plasmon of the present invention comprises a transparent film pattern formed of a plurality of slit-shaped holes having a wavelength of a certain period or less in the metal film, And may include a plurality of slit-shaped grooves provided in an area surrounding the slit-shaped holes.
At this time, only the light of a specific wavelength is selectively transmitted according to the period (a) between the slit-shaped holes by using surface plasmons derived from the surface of the metal film to realize a desired color, and the thickness of the metal film corresponding to each wavelength Are different from each other.

The liquid crystal display device of the present invention is provided on a first substrate and includes a transparent film pattern formed of a plurality of slit-shaped holes having a wavelength of a predetermined period (a) or less in the metal film, and the plurality of slit- A polarizing color filter having a plurality of slit-shaped grooves in an area surrounding the hole, and a second substrate bonded to be opposite to the first substrate.

Another liquid crystal display device of the present invention is a liquid crystal display device provided on an outer surface of a first substrate and having a transmissive film pattern made of a plurality of slit-shaped holes having a wavelength of a certain period or less in a metal film, A polarizing color filter having a plurality of slit-shaped grooves in an area surrounding the slits, and a second substrate facing the first substrate.

Another liquid crystal display device of the present invention includes a thin film transistor provided on a first substrate, and a transmissive film pattern formed on a second substrate, the transmissive film pattern including a plurality of slit-shaped holes having a wavelength of a certain period (a) And a polarizing color filter having a plurality of slit-shaped grooves in an area surrounding the plurality of slit-shaped holes on a surface of the metal film, wherein the first substrate is adhered to and opposed to the second substrate, The polarizing color filter may replace the common electrode or the back ITO.

At this time, the polarizing color filter selectively transmits only light of a specific wavelength according to the period (a) between the slit-shaped holes using the surface plasmon derived from the surface of the metal film to realize a desired color, and corresponds to each wavelength The thickness of the metal film can be made different from each other.
At this time, the plurality of grooves may have a constant period P such that the wavefront vector by the surface plasmons is less than or equal to the lattice vector (2? / P).
The first and second substrates may be formed of a glass substrate. The first and second substrates may further include an insulating layer formed on the metal film including the transparent film pattern and made of the same dielectric material as the glass substrate.

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As described above, the polarizing color filter using the surface plasmon according to the present invention and the liquid crystal display device having the same can be fabricated by forming a color filter having a simple structure using surface plasmon phenomenon without using a conventional dye or pigment, Can be simplified, and the manufacturing cost can be lowered.

The polarizing color filter using the surface plasmon according to the present invention and the liquid crystal display device having the same can solve the problem of decreasing the aperture ratio for ensuring the alignment margin since alignment of the upper and lower substrates is unnecessary, And the power consumption for the backlight is reduced as the number of triple increases. In addition, the liquid crystal display device according to the present invention can minimize the power consumption for the backlight by providing a reflection plate having a one-dimensional lattice arrangement under the backlight and recycling the backlight light source.

The polarizing color filter using the surface plasmon according to the present invention and the liquid crystal display device having the same can realize a multi-primary pixel as the power consumption of the backlight is reduced, thereby providing an image of high color reproduction.

The polarizing color filter using the surface plasmon according to the present invention and the liquid crystal display device having the same can be manufactured by forming an insulating layer on the metal film including the transmissive film pattern with the same or substantially the same refractive index as the substrate, The efficiency and the color reproducibility of the transmitted light can be improved.

A polarizing color filter using a surface plasmon according to the present invention and a liquid crystal display device having the same have a plurality of slit-shaped grooves having periodicity in a region surrounding a plurality of slit- It is possible to improve the viewing angle dependency of the center peak wavelength of the transmitted light and improve the transmittance and the light condensing property. At this time, the transmittance can be controlled by adjusting the number of the grooves, and the transmittance improving effect can be obtained. In addition, since the center peak wavelength of the transmitted light is independent of the viewing angle change, the polarizing color filter using the surface plasmon according to the present invention can be free from the condition of vertical incidence of incident light, that is, restriction to use a condensed light source.

The polarizing color filter using the surface plasmon according to the present invention and the liquid crystal display device having the same have a slit-shaped hole having a very high aspect ratio to linearly polarize the transmitted light, thereby removing a conventional polarizer as the color filter functions as a polarizer So that the manufacturing cost can be reduced and the thickness of the display device can be made slim.

1 is an exploded perspective view schematically showing a structure of a general liquid crystal display device.
BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a color filter.
FIGS. 3A and 3B are a plan view and a sectional view schematically showing a structure of a color filter according to a first embodiment of the present invention, which is manufactured using surface plasmon phenomenon. FIG.
4 is a graph showing a change in the center peak wavelength of transmitted light according to an incident angle.
Figs. 5A and 5B are views showing an example of a change in a hole interval formed by holes due to a viewing angle difference; Fig.
FIGS. 6A and 6B are cross-sectional views illustrating the concept of focusing light at the exit surface of a color filter using surface plasmon and the concept of diverging light. FIG.
7 is a plan view and a partial cross-sectional view schematically showing a polarizing color filter using a surface plasmon according to a second embodiment of the present invention.
8A to 8F are graphs showing the characteristics of the intensity of surface plasmon resonance according to a change in depth of a groove formed in an aluminum metal film exposed to air.
FIG. 9 is a graph showing the relationship between the groove depth and the intensity of surface plasmon resonance obtained from the results of FIGS. 8A to 8F. FIG.
10A to 10F are graphs showing the intensity of surface plasmon resonance according to the number of grooves.
11 is a graph showing the intensity of surface plasmon resonance at a viewing angle of 0 ° according to the change in the number of grooves shown in Figs. 10A to 10F.
12A to 12F are graphs showing the intensity of surface plasmon resonance according to the formation position of the groove.
13 is a sectional view schematically showing a structure of a liquid crystal display device according to a second embodiment of the present invention.
14 is a cross-sectional view schematically showing another structure of a liquid crystal display device according to a second embodiment of the present invention.
FIG. 15 is a plan view schematically showing a part of an array substrate of a liquid crystal display device according to a second embodiment of the present invention shown in FIG. 14; FIG.
16A to 16G are cross-sectional views sequentially showing a manufacturing process of the liquid crystal display device shown in FIG. 14;
Figs. 17A to 17E are plan views sequentially showing the manufacturing steps of the array substrate shown in Fig. 15; Fig.
18 is a cross-sectional view schematically showing a structure of a liquid crystal display device according to a third embodiment of the present invention.

Hereinafter, preferred embodiments of a polarizing color filter, a liquid crystal display, and a manufacturing method thereof using the surface plasmon according to the present invention will be described in detail with reference to the accompanying drawings.

The improvement of the transmissivity through the improvement of the aperture ratio of the existing array substrate is faced with the physical limitations, and therefore, it is necessary to shift the paradigm by improving the transmissivity by removing the color filter rather than improving the aperture ratio.

For this purpose, a method of filtering light by forming a transparent film pattern so that only a specific wavelength of light is selectively transmitted through a predetermined metal film is proposed. A color filter using the surface plasmon phenomenon is formed, And a color filter transmitting blue light.

3A and 3B are a plan view and a cross-sectional view schematically showing a structure of a color filter according to a first embodiment of the present invention manufactured using a surface plasmon phenomenon.

Referring to FIG. 6, when a transmissive film pattern 153 having a plurality of sub-wavelength holes having a predetermined period (a) is formed in a predetermined metal film 152, the transmissive film pattern 153 having a near- As the electric field of the incident light and the plasmon are coupled, only light of a specific wavelength is transmitted, and all the remaining wavelengths are reflected, thereby obtaining selected red, green and blue colors.

For example, when a hole pattern of a wavelength shorter than a predetermined period (a) is formed in a silver film, only light of a specific wavelength of red, green, and blue selected according to the diameter (d) So that the RGB color can be realized and the light transmission can transmit a larger amount of light than the hole area as the light around the hole is drawn.

In order to realize a high-purity color, the thickness of the metal film 152 corresponding to each wavelength may be adjusted as shown in the figure, but the present invention is not limited thereto.

For reference, the plasmon refers to a pseudoparticle in which free electrons induced in the surface of a metal film are collectively vibrated by an electric field of incident light. The surface plasmon refers to a plasmon locally present on the surface of a metal film, And the electromagnetic wave propagating along the interface between the dielectric and the dielectric.

The surface plasmon phenomenon refers to a phenomenon in which light of a specific wavelength and free electrons on a metal film resonate to form light of a specific wavelength when light is incident on a metal film surface having a periodic hole pattern at a nano level, Only light of a specific wavelength capable of forming a surface plasmon by the incident light can pass through the hole, and all the remaining light is reflected by the metal film surface.

In general, a thick metal film has a non-transmissive property with respect to incident light. If the size of the hole formed in the metal film is much smaller than the incident light wavelength, the intensity of transmitted light is remarkably small. However, even if a small hole having a wavelength or less is periodically arranged in the metal film, the transmittance of light is greatly amplified due to the excitation of the surface plasmon. In general, the light or photon does not have its dispersion curve intersecting the dispersion curve of the surface plasmon. Therefore, in order to directly couple the photons to the surface plasmons, a lattice structure of a hole pattern with a certain period is formed on the surface of the metal film to excite the surface plasmons by satisfying the momentum conservation.

By using such characteristics, it becomes possible to transmit light of a desired wavelength by adjusting the transmissive film pattern, specifically, the size of the holes, the spacing between the holes, the permittivity of the adjacent medium, and the thickness of the metal film. When there is a metal film having a square arrangement structure by holes, the center peak wavelength of transmitted light due to the light incident perpendicularly thereto, that is, the surface plasmon resonance wavelength, is given by the following equation.

Equation 1

은 금속의 유전 상수이고,

는 금속에 인접한 유전체 물질의 유전 상수이다. 즉, 투과막 패턴의 주기를 바꾸어 주거나 유전체 물질을 변화시킴으로써 표면 플라즈몬 현상에 의해 투과되는 피크 파장을 조절할 수 있다.here,

Is the dielectric constant of the metal,

Is the dielectric constant of the dielectric material adjacent to the metal. That is, it is possible to control the peak wavelength transmitted by the surface plasmon phenomenon by changing the period of the transmissive film pattern or changing the dielectric material.

At this time, the hole of the transparent film pattern can be changed into various shapes such as an ellipse, a square, a triangle, and a slit as well as a simple circular shape. In case of a circle, the circle size is 50 nm to 10 탆, The period may have a range of 50 nm to 10 탆.

Meanwhile, in the color filter using the surface plasmon according to the first embodiment of the present invention, the width of the center peak wavelength band of the transmitted light and the position of the center peak wavelength greatly depend on the observation angle.

FIG. 4 is a graph showing the change of the center peak wavelength of transmitted light according to the incident angle. FIG. 4 shows the transmittance intensity of the transmitted light measured by varying the incident angle θ from 0 to 24 °.

As shown in the figure, it can be seen that the width of the center peak wavelength band of the transmitted light and the position of the center peak wavelength largely depend on the observation angle, and the rate of change of the center peak wavelength of the transmitted light due to the surface plasmon resonance Is shown as 8.3 nm / degree.

Also, it can be seen that the transmittance of light vertically incident on the color filter becomes maximum, and the transmittance decreases rapidly as the incident angle [theta] increases.

Therefore, if a special light source capable of entering at a narrow angle is used, it is possible to realize a color of a desired wavelength band.

FIGS. 5A and 5B are diagrams illustrating changes in the hole spacing formed by the holes due to the viewing angle difference, respectively. FIG. 5A and FIG. 5B show changes in the hole spacing in the case of incidence at the front incidence and angle θ.

Referring to the drawing, assuming that a distance between adjacent two holes H is P, the effective grating period changes to P x cos? According to the change of the incident angle?, And when the area formed by each hole H is A, The effective cross-sectional area is changed to A × cos θ. Therefore, as the incident angle? Increases, the effective cross-sectional area of the hole H through which the incident light can pass through decreases, and thus the transmittance decreases. Further, as the viewing angle increases, the effective grating period and the diameter of the hole H decrease, so that the position of the center peak wavelength of the transmitted light due to the surface plasmon resonance is shifted.

Therefore, the second embodiment of the present invention aims to manufacture a color filter using a surface plasmon which is emitted in a beam form having excellent collimation and directionality, in addition to the above-mentioned transmittance increasing effect.

The second embodiment of the present invention aims to fabricate a polarizing color filter using a surface plasmon that functions as a polarizer by applying a slit-shaped hole having a very large ratio of aspect ratio, that is, an aspect ratio, .

That is, in the polarizing color filter using the surface plasmon according to the second embodiment of the present invention, a slit-shaped hole having a very large aspect ratio is applied to the hole of the transmissive film pattern to linearly polarize the transmitted light so that the color filter functions as a polarizer It becomes possible to remove the expensive lower polarizing plate. As a result, the manufacturing cost can be reduced, and the thickness of the display device can be reduced.

At this time, the polarizing color filter using the surface plasmon according to the second embodiment of the present invention has a plurality of slit-shaped grooves having periodicity in the area surrounding the plurality of slit- By making a beam shape having a divergent angle, it is possible to improve the viewing angle dependency of the center peak wavelength of the transmitted light, and to improve the transmittance and the light condensing property.

Specifically, when the grooves are formed on the incident surface of the metal film, the funneling effect of the incident light around the slit-shaped holes is enhanced to further increase the transmittance. The amplifying effect of the floodlight occurs because the effect of the reinforcing interference between the surface plasmon waves is generated by the periodic groove formed additionally on the surface of the metal film. When grooves are formed on the exit surface of the metal film, the light transmitted through the surface of the metal film is condensed to suppress the divergence of light, thereby forming a sheet having a separate light-collecting lens array, such as a micro- there is no need to insert a sheet.

The structure proposed by the second embodiment of the present invention has a function of suppressing the dependency of the center peak wavelength of the transmitted light according to the viewing angle or the change of the measuring angle. Particularly, it is possible to suppress light emitted to a boundary region between sub-pixels, thereby reducing the loss of transmitted light. In addition, since there is no color mixing phenomenon between neighboring sub-pixels, it is not necessary to separately form a barrier structure such as a black matrix, and the pixel size can be made small to the level of several hundred nanometers. do.

6A and 6B are cross-sectional views illustrating the concept of focusing light at the exit surface of a color filter using surface plasmons and the concept of diverging light.

As shown in the figure, when the groove h is formed on the outlet side of the metal film 152 ', the directionality of the emitted light and the shape of the transmitted light can be determined.

At this time, if the groove h is formed on the outlet side of the metal film 152 'as described above, the light transmitted through the surface of the metal film 152' can be condensed to suppress the divergence of light. Further, although not shown in the drawing, when the grooves are formed on the incident surface of the metal film, the funnel effect of the incident light around the slit-shaped holes can be enhanced to further increase the transmittance. A method of patterning the periodic grooves h on the surface of the metal film 152 'is etching, milling, or metal deposition.

Specifically, the light incident on the color filter 150 'is transmitted through the nano-sized hole (H) region in a manner coupled with the surface plasmon. At the exit side, the surface-emitting light is separated from the surface plasmon and deviates from the region of the metal film 152 '. At this time, if constant grooves (h) of the period P are formed on the emission surface, surface plasmons are induced in the respective groove (h) regions, and the surface emission lights separated from them cause interference with each other. Under the condition that the wave vector (k _sp ) by the surface plasmon becomes smaller than the grating vector (2? / P), the emitted light proceeds in such a manner that the two beams converge as shown in FIG. 6A . In particular, when the wave number vector is equal to the lattice vector, the transmitted light oscillates in the form of a collimated beam.

7 is a plan view and a partial cross-sectional view schematically showing a polarizing color filter using a surface plasmon according to a second embodiment of the present invention. When a plurality of slit-shaped grooves having periodicity are formed in a region surrounding a slit- For example.

In this case, for the sake of convenience, the polarizing color filter for one pixel composed of sub-color filters corresponding to red, green, and blue from the left is shown as an example, but the present invention is not limited thereto, The present invention is also applicable to the case of implementing multi-primary colors of three or more primary colors.

Although a plurality of slit-shaped grooves are formed on the exit surface of the metal film, the present invention is not limited thereto. The plurality of slit-shaped grooves may be formed on the incident surface side of the metal film It can be formed on both the exit face and the incidence face of the metal film.

As shown in the figure, the polarizing color filter 250 according to the second embodiment of the present invention includes a plurality of slit-shaped holes H having a predetermined period in the row or column direction, So that only the light of a specific wavelength is selectively transmitted therethrough, thereby realizing a desired color.

At this time, the light of the specific wavelength to be selectively transmitted is determined by the period between the slits-shaped holes H, and the period of the slits-shaped holes H may range from 50 nm to 1000 nm.

Since a plurality of slit-shaped grooves h having a periodicity are formed in the region surrounding the plurality of slit-shaped holes H, the viewing angle dependency of the center peak wavelength of the transmitted light is improved, and the transmittance and the light- .

At this time, the transmissive film pattern 253 is formed in the pixel region except the region where the gate line, the data line, and the thin film transistor are located, and a slit-shaped periodic groove (h) pattern is formed in the boundary region between the pixel regions .

The cross-sectional shape of the hole H constituting the transmissive film pattern 253 is characterized by having a slit shape with a very large aspect ratio. In this case, the aspect ratio is defined as a ratio of the length of the major axis to the length of the minor axis formed by a given graphic form, and may have a value of 2 or more, for example. The cross-sectional shape of the groove (h) has a slit shape having a very large aspect ratio, like the cross-sectional shape of the hole (H).

The material of the metal film 252 is preferably aluminum (Al) which can cause surface plasmon resonance in the entire region of the visible light. However, the present invention is not limited thereto. The metal film 252 may be formed of a metal such as Au, Ag, Pt, Cu, Ni, Pd, Selected from the group consisting of Zn, Fe, Cr, Mo, doped semiconductors, carbon nanotubes, fullerene, And a conductive material selected from the group consisting of or a mixture thereof.

In order to realize a high-purity color, the thickness of the metal film 252 corresponding to each wavelength can be adjusted differently, but the present invention is not limited thereto.

Though not shown in the figure, other non-through grooves having no periodicity around the non-through grooves h may be formed.

The slit-shaped hole H having a very high aspect ratio has a very strong polarization characteristic. The transmittance of the incident light having linearly polarized light parallel to the long axis of the slit becomes zero, and the incident light having linearly polarized light perpendicular to the long axis of the slit And has a maximum transmittance. Therefore, in the case of the polarizing color filter 250 using the surface plasmon according to the second embodiment of the present invention, since the light transmitted through the polarizing color filter 250 has the linear polarization characteristic, the conventional polarizing plate can be removed .

At this time, the transmittance of the incident light is proportional to the number of the non-through grooves h around the hole H, and in consideration of the fact that the non-through grooves h are formed on both sides of the hole H, do. The absolute transmittance is proportional to the number of the through holes H, the peak wavelength of the transmitted light is linearly proportional to the period P, and depends on the dielectric constant of the medium adjacent to the metal film 252.

8A to 8F are graphs showing the characteristics of the intensity of surface plasmon resonance according to the depth change of the groove formed in the aluminum metal film exposed to the air. And the intensity of surface plasmon resonance according to the groove depth in the color filter is simulated.

9 is a graph showing the relationship between the groove depth and the intensity of surface plasmon resonance obtained from the results of FIGS. 8A to 8F.

In this case, the slit-shaped holes and grooves of the polarizing color filter used in the simulation have a width of 40 nm and a pitch of 7 nm and 4 × 2, respectively, and the period of the grooves is 600 nm. 8a, 8b, 8c, 8d, 8e and 8f show the intensity of the surface plasmon resonance when the depth of the groove is 30 nm, 50 nm, 70 nm, 90 nm, 110 nm and 130 nm, respectively.

As shown in the figure, when grooves having a depth of 30 nm to 130 nm are formed on the outlet side of a metal film made of aluminum, it is found that the intensity of surface plasmon resonance is optimized in the transmittance when the groove depth is 50 nm .

8A to 8F show transmittance intensities measured at various viewing angles of 0 DEG, 4 DEG, 8 DEG and 12 DEG.

10A to 10F are graphs showing the intensity of surface plasmon resonance according to the number of grooves. In a polarizing color filter in which a dielectric material similar to the refractive index of a glass substrate is deposited on a metal film made of aluminum, And the result of simulation of the resonance intensity is shown. For reference, FIGS. 10A to 10F show transmittance intensities measured at various viewing angles of 0 DEG, 4 DEG, 8 DEG and 12 DEG.

11 is a graph showing the intensity of surface plasmon resonance at a viewing angle of 0 ° according to the change of the number of grooves shown in FIGS. 10A to 10F.

In this case, the slit-shaped holes and grooves of the polarizing color filter used in the simulation have a width of 40 nm, and the depth and period of the grooves are 50 nm and 600 nm, respectively. FIGS. 10A, 10B, 10C, 10D, 10E, and 10F show that the number of grooves is 1 x 2, 2 x 2, 3 x 2, 4 x 2, 5 x 2, and 6 x 2 shows the intensity of surface plasmon resonance.

As shown in Fig. 10, in the case where 1x2 to 6x2 grooves are formed on the outlet side of the metal film made of aluminum, the intensity of the surface plasmon resonance increases as the number of grooves increases and the transmittance due to the surface plasmon effect As shown in FIG. 11, when the number of grooves is 3 × 2 or more, the transmittance converges to a constant value.

12A to 12F are graphs showing the intensity of surface plasmon resonance according to the positions of grooves. In a polarizing color filter in which a dielectric material similar to the refractive index of a glass substrate is deposited on a metal film made of aluminum, And the intensity of the surface plasmon resonance is simulated.

In this case, the slit-shaped holes and grooves of the polarizing color filter used in the simulation are 40 nm wide and 7 and 5 × 2, respectively, and the depth and period of the grooves are 60 nm and 600 nm, respectively 12A, 12B, 12C and 12D, and 12E and 12F show the intensity of the surface plasmon resonance in the case where grooves are formed on both the exit surface, the incident surface, and the exit surface and the incident surface of the metal film, respectively Respectively.

12A, 12C and 12E show the intensity of the surface plasmon resonance in the case where the polarization direction of the incident light is P-polarized light in a direction perpendicular to the long axis of the slit. FIGS. 12B, 12D and 12F show the intensity of the surface plasmon resonance Is the S polarized light in the direction parallel to the long axis of the slit.

As shown in the figure, the case of forming a groove on the side of the metal film exit plane of aluminum, the intensity of the transmittance of the P polarized light and S polarized light at the wavelength of approximately 620nm and 625nm respectively, is 4.87 × 10 ^-11 and 2.12 × 10 ^{respectively 15 shows} that the extinction ratio of the transmitted light to the P-polarized light and the S-polarized light is about 2.29 × 10 ^{4. When} grooves are formed on the incident surface of the metal film, the extinction ratio of about 620 nm and 605 nm It can be seen that the intensities of the transmittances of the P polarized light and the S polarized light at the wavelengths are 1.06 × 10 ^-10 and 3.74 × 10 ^-15 , respectively, and the intensity ratio of the transmitted light to the P polarized light and the S polarized light is about 2.83 × 10 ⁴

When grooves are formed on both the exit face and the incident face of the metal film, the transmittance intensities of the P polarized light and the S polarized light at the wavelengths of approximately 620 nm and 605 nm are respectively 1.43 x 10 ^-10 and 4.31 x 10 ^-15 The intensity ratio of the transmitted light to the P-polarized light and the S-polarized light is about 3.32 × 10 ⁴ (~30,000: 1).

The intensity ratio of the transmitted light to the P-polarized light and the S-polarized light is largest when grooves are formed on both the exit surface and the incident surface of the metal film, and strong surface plasmon resonance induction in the incident light having P- And at the same time, the transmittance of the incident light having S-polarized light is strongly suppressed.

At this time, even if a slit-shaped groove is formed only on the incident surface of the metal film, the transmittance can be improved and the characteristics of the polarizing color filter can be obtained.

The full width at half maximum (FWHM) of the emitted light from the slit-shaped groove having a slit-shaped groove in the periphery shows a strong light condensing property of transmitted light within 6 °.

In addition, it can be seen that the change of the central peak wavelength with respect to the viewing angle change (0 ° to 20 °) is remarkably improved in the viewing angle dependency within 0.5 nm / degree. For reference, the color purity can be improved by suppressing the second peak emitted in the 480 nm band, and when the groove is formed on the incident side, the transmittance ratio of the first peak and the second peak increases from 1.74 times to 3.13 times .

In the polarizing color filter having the above structure, when light is incident from the lower side of the substrate, only light of a specific wavelength determined by the lattice period of the transmissive film pattern is transmitted through the color filter. In addition, it is possible to divide the same metal film into a plurality of regions having different periods of the transmissive film pattern, and selectively transmit light of different wavelengths in the divided regions.

Thus, a transmissive film pattern composed of a plurality of slit-shaped holes having a specific period and a width is formed in a metal film and used as a color filter by using a surface plasmon phenomenon occurring in a metal film. By applying this to a liquid crystal display device, .

In addition, by applying a slit-shaped hole having a very large aspect ratio to linearly polarize the transmitted light, the color filter can function as a polarizer.

At this time, the conventional color filter is formed on the upper color filter substrate. However, the polarizing color filter using the surface plasmon suggested in the present invention is not limited to the upper color filter substrate, but may be formed on the lower array substrate or the substrate.

In addition, it is possible to fabricate a thin film transistor through a high-temperature process on a metal film because the metal film functions as a color filter, unlike the conventional pigment or dye type color filter, which can not be processed at high temperature. It is possible to solve the problem that the conventional liquid crystal display device has to reduce the aperture ratio in order to secure alignment margins for attaching the upper color filter substrate and the lower array substrate.

13 and 14 are cross-sectional views schematically showing the structure of a liquid crystal display device according to a second embodiment of the present invention. For convenience of explanation, the same reference numerals are applied to substantially the same constituent elements.

As described above, in the polarizing color filter of the liquid crystal display according to the second embodiment of the present invention, a transmissive film pattern composed of a plurality of slit-shaped holes having a predetermined period in a row or column direction and having a wavelength or less So that only a specific wavelength of light is selectively transmitted to realize a desired color.

Particularly, since the polarizing color filter according to the second embodiment of the present invention has a plurality of slit-shaped grooves having periodicity in the area surrounding the plurality of slit-shaped holes, the viewing angle dependency of the center peak wavelength of the transmitted light And the transmittance and the light condensing property can be improved.

In this case, a plurality of slit-shaped grooves are formed on the incident surface of the metal film, but the present invention is not limited thereto. The plurality of slit-shaped grooves may be formed on the exit surface side of the metal film It can be formed on both the exit face and the incidence face of the metal film.

In the polarizing color filter according to the second embodiment of the present invention, a slit-shaped hole having a very large aspect ratio is applied to the hole of the transmission film pattern to linearly polarize the transmitted light so that the color filter functions as a polarizer, And the lower polarizer can be removed.

13, a polarizing color filter 250 according to the second embodiment of the present invention is formed on the upper color filter substrate 205. In the polarizing color filter 250, There is a way.

At this time, the advantage that can be obtained is that a transmissive film pattern is formed by a one-step process on a single metal film to realize RGB, and it is used instead of the upper ITO common electrode or the rear ITO, Can be saved.

As described above, since the polarizing color filter 250 using the surface plasmon is advantageous in terms of color purity and transmittance when the refractive index matching condition is established between the dielectric materials around the metal film 252, a polarizing color filter It is appropriate to form an insulating layer 206 made of a dielectric material substantially the same as the glass substrate such as SiO ₂ on the metal film 252 including the transmissive film pattern 253.

The color filter substrate 205 thus formed is fixed to the array substrate 210 by a sealant (not shown) formed on the outer periphery of the image display region in a state where a certain cell gap is maintained by the column spacer 260, In this case, the array substrate 210 is provided with a plurality of gate lines (not shown) and data lines (not shown) arranged vertically and horizontally to define a plurality of pixel regions, And a pixel electrode 218 formed on the pixel region.

The thin film transistor includes a gate electrode 221 connected to the gate line, a source electrode 222 connected to the data line, and a drain electrode 223 connected to the pixel electrode 218. The thin film transistor includes a first insulating layer 215a for insulating between the gate electrode 221 and the source and drain electrodes 222 and 223 and a first insulating layer 215b for insulating between the source and drain electrodes 222 and 223 by a gate voltage supplied to the gate electrode 221. [ And an active layer 224 forming a conductive channel between the drain electrode 222 and the drain electrode 223. Reference numerals 215b and 225n denote an ohmic contact layer for making ohmic contact between the second insulating layer and the source / drain region of the active layer 224 and the source / drain electrodes 222 and 223, respectively. .

On the other hand, polarizing color filters using surface plasmons have advantages in that they are not damaged by a high-temperature process because they use a metal film. And a color filter is formed on the array substrate by drawing attention to this.

In this case, the polarizing color filter 250 using the surface plasmon can be positioned inside the cell, that is, under the thin film transistor array. As shown in FIG. 14, As shown in Fig.

In this case, a common electrode 208 except for the color filter and the black matrix may be formed on the upper color filter substrate 205, and the polarizing color filter 250 using the surface plasmon formed on the array substrate 210 may be a floating ) Or grounded.

When the polarizing color filter 250 is formed on the array substrate 210 as described above, it is not necessary to secure a margin for aligning the upper color filter substrate 205 and the lower array substrate 210, It is possible to improve the transmittance of the panel. As the panel transmittance is improved, the brightness of the backlight can be reduced, thereby reducing the power consumption for the backlight.

As the power consumption of the backlight is reduced as described above, it is possible to realize a multi-primary-color pixel, thereby providing an effect of obtaining a high-quality color reproduction image.

Further, when the polarizing color filter 250 is formed on the array substrate 210 to remove the color filter process line, the facility investment cost and the construction cost can be reduced by about 50%.

In particular, the polarizing color filter 250 using the surface plasmon according to the second embodiment of the present invention can remove the upper polarizer or the lower polarizer due to the function of the polarizer, The thickness can be made slim.

Reference numerals 201 and 211 denote an upper polarizer and a lower polarizer, respectively.

Hereinafter, a structure of a liquid crystal display device and a manufacturing method thereof when a polarizing color filter using the surface plasmon as described above is formed on an array substrate will be described in detail with reference to the drawings.

15 is a plan view schematically showing a part of an array substrate of a liquid crystal display device according to a second embodiment of the present invention shown in FIG.

Here, for convenience of explanation, one pixel composed of sub-color filters corresponding to red, green, and blue colors is shown as an example from the left. However, the present invention is not limited thereto, and the present invention can also be applied to a case of implementing multi-primary colors of three or more colors.

The sub-pixels corresponding to the red, green and blue colors have substantially the same constituents except for the structure of the transmissive film pattern, that is, the width and the interval of the slit-shaped holes.

In addition, the liquid crystal display according to the second embodiment of the present invention is exemplified by a twisted nematic (TN) liquid crystal display device in which nematic liquid crystal molecules are driven in a direction perpendicular to a substrate, The present invention is not limited thereto.

As shown in the drawing, a gate line 216 and a data line 217, which are vertically and horizontally arranged on the array substrate 210 to define a pixel region, are formed on the array substrate 210 according to the second embodiment of the present invention. Respectively. A thin film transistor, which is a switching device, is formed in the intersection region of the gate line 216 and the data line 217. The thin film transistor is connected to the thin film transistor, And a pixel electrode 218 for driving the liquid crystal layer are formed.

The thin film transistor includes a gate electrode 221 constituting a part of the gate line 216, a source electrode 222 connected to the data line 217 and a drain electrode 223 connected to the pixel electrode 218 do. The thin film transistor includes a first insulating layer (not shown) for insulating the gate electrode 221 from the source / drain electrodes 222 and 223 and a second insulating layer (Not shown) that forms a conduction channel between the drain electrode 222 and the drain electrode 223.

A part of the source electrode 222 extends in one direction to constitute a part of the data line 217. A part of the drain electrode 223 extends toward the pixel region and is connected to a second insulating film (not shown) And is electrically connected to the pixel electrode 218 through the contact hole 240 formed therein.

Particularly, the polarizing color filter 250 using the surface plasmon according to the second embodiment of the present invention is disposed on the array substrate 210. The polarizing color filter 250 is formed on the array substrate 210, And a plurality of slit-shaped holes (H) having a period of less than or equal to the wavelength of the incident light having a wavelength of about 300 nm or less. The field of the incident light having a near-infrared band from the visible light and the plasmon are coupled, Only the light of the corresponding wavelength is transmitted and all the remaining wavelengths are reflected, thereby obtaining RGB colors.

At this time, the transmissive film pattern 253 is formed in the pixel region except the region where the gate line 216, the data line 217, and the thin film transistor are located.

As described above, the polarizing color filter 250 according to the second embodiment of the present invention has a plurality of slit-shaped grooves h having a periodicity in an area surrounding the plurality of slit-shaped holes H It is possible to improve the viewing angle dependency of the center peak wavelength of the transmitted light and to improve the transmittance and the light condensing property.

The slit-shaped holes H constituting the transmissive film pattern 253 are formed in a slit shape having a very high aspect ratio to linearly polarize the transmitted light so that the polarizing color filter 250 functions as a polarizer, Can be removed.

The material of the metal film 252 may be selected from the group consisting of aluminum, gold, silver, platinum, copper, nickel, palladium, zinc, iron, chromium, molybdenum, doped semiconductors, carbon nanotubes, fullerenes, And the like, or a mixture thereof. The conductive material may be selected from the group consisting of, for example,

In order to realize a high-purity color, the thickness of the metal film 252 corresponding to each wavelength can be adjusted differently, but the present invention is not limited thereto.

At this time, the light of the specific wavelength to be selectively transmitted is determined by the period between the slits-shaped holes H, and the period of the slits-shaped holes H may have a range of 10 nm to 1000 nm.

Though not shown in the figure, other non-through grooves having no periodicity around the non-through grooves h may be formed.

FIGS. 16A to 16G are sectional views sequentially showing the manufacturing process of the liquid crystal display device shown in FIG. 14, and FIGS. 17A to 17E are plan views sequentially showing the manufacturing steps of the array substrate shown in FIG.

16A and 17A, a polarizing color filter 250 using a surface plasmon according to the second embodiment of the present invention is formed on an array substrate 210 made of a transparent insulating material such as glass.

At this time, the polarizing color filter 250 has a transmissive film pattern 253 formed of a plurality of slit-shaped holes H having a predetermined period or less in a predetermined metal film 252, As the plasmon is coupled with the electric field of the incident light having the band, only the light of wavelength corresponding to red, green and blue is transmitted, and all the remaining wavelengths are reflected, thereby obtaining RGB color.

Here, the slit-shaped hole H is formed such that the major axis of the slit is substantially the same as the direction of the data line 217. However, the present invention is not limited thereto, The hole H of the gate line 216 may be formed such that the long axis of the slit has the same direction as the direction of the gate line 216. [

In particular, since a plurality of slit-shaped grooves h having a periodicity are formed in the region surrounding the plurality of slit-shaped holes H, the viewing angle dependence of the center peak wavelength of transmitted light is improved and the transmittance and the light- .

Although a plurality of slit-shaped grooves h are formed on the incident surface of the metal film 252, the present invention is not limited thereto, and a plurality of slit- h may be formed on the exit face of the metal film 252 or on both the exit face and the incident face of the metal film 252.

The slit-shaped holes H constituting the transmissive film pattern 253 are formed in a slit shape having a very high aspect ratio to linearly polarize the transmitted light so that the polarizing color filter 250 functions as a polarizer, Can be removed.

The slit-shaped hole H having a very high aspect ratio has a very strong polarization characteristic. The transmittance of the incident light having linearly polarized light parallel to the long axis of the slit becomes zero, and the incident light having linearly polarized light perpendicular to the long axis of the slit And has a maximum transmittance. Therefore, in the case of the polarizing color filter 250 using the surface plasmon according to the second embodiment of the present invention, since the light transmitted through the polarizing color filter 250 has the linear polarization characteristic, the conventional polarizing plate can be removed .

At this time, the transmittance of the incident light is proportional to the number of the non-through grooves h around the hole H. Considering that the non-through grooves h are formed on both sides of the hole H, do. The absolute transmittance is proportional to the number of the through holes H, the peak wavelength of the transmitted light is linearly proportional to the period P, and depends on the dielectric constant of the medium adjacent to the metal film 252.

The material of the metal film 252 may be selected from the group consisting of aluminum, gold, silver, platinum, copper, nickel, palladium, zinc, iron, chromium, molybdenum, doped semiconductors, carbon nanotubes, fullerenes, And the like, or a mixture thereof. The conductive material may be selected from the group consisting of, for example, The metal film 252 may be formed by any one of a vapor deposition method, a liquid phase method, a solid phase method and a nano-sol coating method. The transmissive film pattern 253 may be formed by electron beam lithography the laser beam may be formed by any one of lithography, ion beam milling, nanosphere lithography, nano imprinting, photolithography, and laser interference lithography. .

In order to realize a high-purity color, the thickness of the metal film 252 corresponding to each wavelength can be adjusted differently, but the present invention is not limited thereto.

In addition, the light having the specific wavelength to be selectively transmitted is determined by the period between the slits (H), and the period of the slits (H) may range from 10 nm to 1000 nm.

Though not shown in the figure, other non-through grooves having no periodicity around the non-through grooves h may be formed.

A predetermined insulating layer 206 is formed on the metal film 252 including the transmissive film pattern 253 to deposit a dielectric material having the same or substantially the same refractive index as that of the array substrate 210 and planarize the surface thereof. .

At this time, the dielectric material may be filled in the plurality of slit-shaped holes H and the grooves h.

In the polarizing color filter 250 according to the second embodiment of the present invention having the above structure, the red color is selectively transmitted through the transmissive film pattern for red color in the red color area, and the transmissive film pattern for green color in the green color area is And the blue color is selectively transmitted through the transmissive film pattern for the blue color in the blue color area, thereby realizing the RGB color.

Next, as shown in FIGS. 16B and 17B, a gate electrode 221 and a gate line 216 are formed on the array substrate 210 on which the insulating layer 206 is formed.

At this time, the gate electrode 221 and the gate line 216 are formed by selectively depositing a first conductive film on the entire surface of the array substrate 210 and then performing a photolithography process.

Here, as the first conductive film, a low resistance opaque conductive material such as aluminum, aluminum alloy, tungsten, copper, chromium, molybdenum, or molybdenum alloy may be used. Also, the first conductive layer may be formed in a multi-layered structure in which two or more low-resistance conductive materials are stacked.

Next, as shown in FIGS. 16C and 17C, a first insulating layer 215a, an amorphous silicon thin film, an n + amorphous silicon thin film (not shown) are formed on the entire surface of the array substrate 210 on which the gate electrode 221 and the gate line 216 are formed. And an active layer 224 made of the amorphous silicon thin film is formed on the array substrate 210 by selectively removing the second conductive layer through a photolithography process, Source / drain electrodes 222 and 223 which are electrically connected to the source / drain regions of the active layer 224 are formed.

The data line 217 is formed of the second conductive film through the photolithography process and crosses the gate line 216 to define a pixel region.

At this time, on the active layer 224, an ohmic-contact layer 225n is formed of the n + amorphous silicon thin film and is patterned in the same manner as the source / drain electrodes 222 and 223.

In addition, an amorphous silicon thin film pattern (not shown) and an n + amorphous silicon thin film (not shown) formed of the amorphous silicon thin film and the n + amorphous silicon thin film and substantially patterned in the same manner as the data line 217 are formed under the data line 217, A pattern (not shown) is formed.

Here, the active layer 224 and the source / drain electrodes 222 and 223 and the data line 217 according to the second embodiment of the present invention can be formed simultaneously with a single mask process using a half-tone mask or a diffraction mask .

At this time, the second conductive layer may be formed of a low-resistance opaque conductive material such as aluminum, aluminum alloy, tungsten, copper, chromium, molybdenum and molybdenum alloy to form a source electrode, a drain electrode and a data line. The second conductive layer may be formed in a multi-layered structure in which two or more low-resistance conductive materials are stacked.

16D and 17D, a second insulating layer 215b (not shown) is formed on the entire surface of the array substrate 210 on which the active layer 224, the source / drain electrodes 222 and 223 and the data line 217 are formed, The second insulating layer 215b is selectively removed through a photolithography process to form a contact hole 240 exposing a part of the drain electrode 223 on the array substrate 210. [

Here, the second insulating layer 215b may be an inorganic insulating layer such as a silicon nitride layer or a silicon oxide layer, or may be an organic insulating layer such as photo acrylic or benzocyclobutene (BCB).

Next, as shown in FIGS. 16E and 17E, a third conductive layer is formed on the entire surface of the array substrate 210 on which the second insulating layer 215b is formed, and then selectively removed through a photolithography process, And a pixel electrode 218 electrically connected to the drain electrode 223 through the through hole 240 is formed.

Here, the third conductive layer may include a transparent conductive material having a high transmittance such as indium tin oxide (ITO) or indium zinc oxide (IZO) to form a pixel electrode.

16F, the array substrate according to the second embodiment of the present invention has a sealant (not shown) formed on the periphery of the image display region in a state where a certain cell gap is maintained by the column spacer 260, The color filter substrate 205 and the color filter substrate 205 are bonded together.

At this time, a common electrode 208 may be formed on the color filter substrate 205 except for a color filter and a black matrix.

16G, the upper polarizer 201 is attached to the outer surface of the color filter substrate 205. [

At this time, when the TN polarizer 201 is driven in a normally white mode in the TN mode, the upper polarizer 201 is stretched in the substantially same direction as the longitudinal direction of the slit of the polarizing color filter 250 , The polarizing color filter 250 functions as a polarizer, as described above, so that the lower polarizer can be removed.

In the liquid crystal display device, a backlight light source is positioned below the liquid crystal display panel, and the backlight is irradiated to the liquid crystal display panel. A reflection plate having a one dimensional grating array is disposed under the backlight light source, It is possible to re-reflect the incident light of a specific wavelength band that is not suitable for the color filter region into the appropriate color filter region or to convert the incident light of the S polarized component into the P polarized light and re-enter the back light source. The liquid crystal display device will be described in detail.

18 is a cross-sectional view schematically showing a structure of a liquid crystal display device according to a third embodiment of the present invention, except that a reflection plate having a one-dimensional lattice arrangement is provided below a backlight light source, And has the same structure as the liquid crystal display device according to the embodiment.

As shown in the figure, the array substrate 310 according to the third embodiment of the present invention includes a gate line 316 arranged vertically and horizontally on the array substrate 310 to define a pixel region, a data line (not shown) Respectively. In addition, a thin film transistor, which is a switching device, is formed in the intersection region of the gate line 316 and the data line, and is connected to the thin film transistor in the pixel region to be connected to the common electrode 308 of the color filter substrate 305 And a pixel electrode 318 for driving the liquid crystal layer is formed.

The thin film transistor includes a gate electrode 321 constituting a part of the gate line 316, a source electrode 322 connected to the data line and a drain electrode 323 connected to the pixel electrode 318. The thin film transistor includes a first insulating layer 315a for insulating the gate electrode 321 from the source and drain electrodes 322 and 323 and a source electrode And an active layer 324 that forms a conduction channel between the drain electrode 322 and the drain electrode 323.

At this time, a part of the source electrode 322 extends in one direction to form a part of the data line, and a part of the drain electrode 323 extends toward the pixel region to form a contact hole formed in the second insulating layer 315b The pixel electrode 318 is electrically connected to the pixel electrode 318. [

Particularly, on the array substrate 310, a polarizing color filter 350 using surface plasmon according to the third embodiment of the present invention is positioned. The polarizing color filter 350 has a predetermined A transmission film pattern 353 composed of a plurality of slit-shaped holes H having a period of not more than a wavelength is formed so that an electric field of an incident light having a near infrared ray band in a visible ray and a plasmon are coupled to each other, Only the light of the corresponding wavelength is transmitted and all the remaining wavelengths are reflected, thereby obtaining RGB colors.

As described above, the polarizing color filter 350 according to the third embodiment of the present invention has a plurality of slit-shaped grooves h having a periodicity in an area surrounding the plurality of slit-shaped holes H It is possible to improve the viewing angle dependency of the center peak wavelength of the transmitted light and to improve the transmittance and the light condensing property.

At this time, the transmissive film pattern 353 is formed in the pixel region except the region where the gate line 316, the data line and the thin film transistor are located, and the transmissive film pattern 353 is formed in the boundary region between the pixel regions, h) pattern can be formed.

The slit-shaped holes H constituting the transmissive film pattern 353 are formed in a slit shape having a very high aspect ratio to linearly polarize the transmitted light so that the polarizing color filter 350 functions as a polarizer, Can be removed.

The material of the metal film 352 may be selected from the group consisting of aluminum, gold, silver, platinum, copper, nickel, palladium, zinc, iron, chromium, molybdenum, doped semiconductors, carbon nanotubes, fullerenes, And the like, or a mixture thereof. The conductive material may be selected from the group consisting of, for example,

In order to realize high color purity, the thickness of the metal film 352 corresponding to each wavelength can be adjusted differently, but the present invention is not limited thereto.

At this time, the light of the specific wavelength to be selectively transmitted is determined by the period between the slits-shaped holes H, and the period of the slits-shaped holes H may have a range of 10 nm to 1000 nm.

Though not shown in the figure, other non-through grooves having no periodicity around the non-through grooves h may be formed.

In the array substrate 310 according to the third embodiment of the present invention, a sealant (not shown) formed on the outer periphery of the image display region maintains a certain cell gap by the column spacer 360, And the upper polarizer 301 may be attached to the outer surface of the color filter substrate 305.

In this case, when the upper polarizer 301 is driven in the normally white mode in the TN mode, the upper polarizer 301 is stretched in the substantially same direction as the long axis direction of the slit of the polarizing color filter 350. As described above, The lower polarizer can be removed because the filter 350 functions as a polarizer.

A backlight light source 370 is disposed under the liquid crystal display panel in which the color filter substrate 305 and the array substrate 310 are bonded together to irradiate the backlight with the liquid crystal display panel. A reflection plate 380 having a one-dimensional grating 385 array is provided to reflect incident light of a specific wavelength band which can not be selectively transmitted to an appropriate color filter region or to convert incident light of S polarization component into P polarized light and re- Can be recycled.

At this time, the backlight light source 370 is positioned on the lower side of the liquid crystal display panel, and a light guide plate 375 for guiding the light emitted from the backlight light source 370 toward the liquid crystal display panel is provided below the liquid crystal display panel .

A reflection plate 380 having an array of the one-dimensional gratings 385 described above is provided below the light guide plate 375.

The polarizing color filter 350 including the plurality of slit-shaped holes H reflects the light (S polarized light) polarized parallel to the long axis of the slit strongly toward the light guide plate 375, (P polarized light) component in a direction perpendicular to the width direction perpendicular to the direction perpendicular to the direction of the incident light, the polarized light has a function as a polarizer or a wavelength separator for incident light by selectively transmitting light having a predetermined wavelength band. The reflector 380 having the one-dimensional grating 385 array has a polarizing converter that has a good reflection property and changes the light of the S polarized light component into the light of the P polarized light component and re-enters the light guide plate 375, The use of the polarizing color filter 350 together with the polarizing color filter 350 can contribute to the improvement of the brightness by recycling the backlight and can replace the conventional reflector. That is, when resonance is not transmitted through the light incident on a given polarizing color filter 350 and reflection occurs, the reflected light is transmitted through the reflection plate 380 to a neighboring color filter region having a suitable transmission wavelength, It is converted into light having a polarized state, is re-incident and eventually transmitted, and thus has a function of recycling the backlight, which has an advantage that power consumption can be reduced.

The reflection plate 380 is made of a metallic thin film or the surface layer of the reflection plate 380 is coated with a conductive dielectric material or a metal such as aluminum, gold, silver, copper, palladium or the like.

The arrangement direction of the one-dimensional grating 385 formed on the reflection plate 380 may not be parallel to the grating arrangement direction of the polarizing color filter 350, that is, the major axis direction of the slit. The one-dimensional grating 385 of the reflection plate 380 has an optimum angle for polarization conversion of 45 ° to 50 °. The long axis direction of the one-dimensional grating 385 of the reflection plate 380 may have a range of +/- 45 degrees with respect to the major axis direction of the slit of the polarizing color filter 350 and +/- 30 degrees with a central angle.

In addition, the one-dimensional grating 3850 may have a triangular, semicircular, rectangular, and trapezoidal shape in cross section and may have a periodicity in a stripe shape.

Although the amorphous silicon thin film transistor using the amorphous silicon thin film as the active layer is described as an example of the first to third embodiments of the present invention, the present invention is not limited to this, A polycrystalline silicon thin film transistor using a silicon thin film, and an oxide thin film transistor using an oxide semiconductor.

In addition, the present invention can be applied not only to a liquid crystal display device but also to other display devices manufactured using thin film transistors, for example, organic electroluminescent display devices in which organic light emitting diodes (OLEDs) have.

While a great many are described in the foregoing description, it should be construed as an example of preferred embodiments rather than limiting the scope of the invention. Therefore, the invention should not be construed as limited to the embodiments described, but should be determined by equivalents to the appended claims and the claims.

150, 150a to 150c, 250, 350: Color filters 152, 152a to 152c, 252, 352:
153, 153a to 153c, 253, 353: transmission film patterns 205, 305: color filter substrate
206, 306: insulating layer 210, 310:
370: Backlight source 375: Light guide plate
380: reflector 385: one-dimensional grating
h: groove H: hole

Claims (26)

Metal film;
A transmissive film pattern formed of a plurality of slit-shaped holes each having a wavelength of a certain period (a) or less in the metal film; And
And a plurality of slit-shaped grooves provided in an area surrounding the plurality of slit-shaped holes on the surface of the metal film,
A surface plasmon derived from the surface of the metal film is used to selectively transmit light of a specific wavelength according to the period (a) between the slit-shaped holes to realize a desired color,
Wherein a thickness of the metal film corresponding to each wavelength is made different from that of the surface plasmon. The polarized color filter according to claim 1, wherein the plurality of grooves have a constant period (P) such that the wavefront vector by the surface plasmon is less than or equal to a grid vector (2? / P). The polarized color filter according to claim 1, wherein the cross-sectional shape of the slit-shaped holes and the grooves is a slit-shaped aspect ratio of 2 or more. The method according to claim 1, wherein the metal film is made of aluminum, gold, silver, platinum, copper, nickel, palladium, zinc, iron, chromium, molybdenum, doped semiconductors, carbon nanotubes, fullerenes, conductive plastics and electrically conductive composites And a conductive material selected from the group consisting of a conductive material including at least one selected from the group consisting of a conductive material, a conductive material, and a mixture thereof. The polarized color filter according to claim 3, wherein the metal film having a plurality of slit-shaped holes is made of a surface plasmon that selectively transmits linearly polarized light in a specific direction. The polarizing color filter according to claim 1, wherein the transmissive film pattern is divided into a plurality of regions having different periods (a) of the holes. The polarized color filter according to claim 1, wherein the slit-shaped groove is provided on an incident surface or an exit surface of the metal film, or a surface plasmon provided on both the incident surface and the exit surface. The surface plasmon resonator according to claim 1, wherein the first substrate comprises a glass substrate, a surface plasmon provided on the metal film including the transparent film pattern, and further comprising an insulating layer made of the same dielectric material as the glass substrate, Used polarized color filter. A plurality of slit-shaped holes are formed in the metal film, the metal film having a plurality of slit-shaped holes each having a wavelength of a predetermined period (a) or less, and a plurality of slit- A polarizing color filter having a plurality of slit-shaped grooves for selectively transmitting light of a specific wavelength according to a period (a) between the slit-shaped holes using a surface plasmon derived from the surface of the metal film to realize a desired color;
A thin film transistor provided on the polarizing color filter;
A second substrate bonded to and facing the first substrate; And
And a polarizer attached to an outer surface of the second substrate,
And the thickness of the metal film corresponding to each wavelength is made different from each other. A plurality of slit-shaped holes formed in a surface of the first substrate and having a plurality of slit-shaped holes each having a wavelength of a predetermined period (a) Wherein a plurality of slit-shaped grooves are provided on the surface of the metal film to selectively transmit light of a specific wavelength according to a period (a) between the slit-shaped holes using a surface plasmon derived from the surface of the metal film, filter;
A thin film transistor provided on an inner surface of the first substrate;
A second substrate bonded to and facing the first substrate; And
And a polarizer attached to an outer surface of the second substrate,
And the thickness of the metal film corresponding to each wavelength is made different from each other. A thin film transistor provided on the first substrate;
A polarizer attached to an outer surface of the first substrate; And
And a plurality of slit-shaped holes in the metal film, the slit-shaped holes being formed in the metal film at a predetermined wavelength (a) or less, and a plurality of slit- A slit-shaped groove is provided, and a polarizing color filter is used to selectively transmit light of a specific wavelength according to a period (a) between the slit-shaped holes using a surface plasmon derived from the surface of the metal film to realize a desired color In addition,
Wherein the first substrate is bonded to the second substrate opposite to the first substrate, the polarizing color filter is a common electrode or a rear ITO,
And the thickness of the metal film corresponding to each wavelength is made different from each other. delete The liquid crystal display device according to any one of claims 9 to 11, wherein the cross-sectional shape of the slit-shaped hole and the groove has a slit shape having an aspect ratio of 2 or more. 14. The method of claim 13, wherein the metal film is made of aluminum, gold, silver, platinum, copper, nickel, palladium, zinc, iron, chromium, molybdenum, doped semiconductors, carbon nanotubes, fullerenes, conductive plastics and electrically conductive composites And a conductive material including at least one selected from the group consisting of a conductive material selected from the group consisting of a conductive material and a conductive material. 14. The liquid crystal display of claim 13, wherein the plurality of grooves have a constant period (P) such that a wavenumber vector by the surface plasmon is less than or equal to a lattice vector (2? / P). 14. The liquid crystal display of claim 13, wherein the transmissive film pattern is divided into a plurality of regions having different periods (a) of the holes. 14. The liquid crystal display of claim 13, wherein the slit-shaped groove is provided on an incident surface or an exit surface of the metal film, or on both the incident surface and the exit surface. 14. The method of claim 13, wherein the first and second substrates are formed of a glass substrate and further include an insulating layer provided on the metal film including the transparent film pattern and made of the same dielectric material as the glass substrate Liquid crystal display device. 14. The liquid crystal display of claim 13, wherein the transmissive film pattern is provided in a pixel region excluding a gate line, a data line, and a region where the thin film transistor is located. 20. The liquid crystal display of claim 19, wherein the slit-shaped grooves are provided in a boundary region between the pixel regions to replace the black matrix. 14. The liquid crystal display device according to claim 13, wherein the polarizing color filter reflects light of an S polarized component polarized in parallel with a long axis of the slit, and transmits a linearly polarized P polarized light component selectively passing through the slit, Display device. The liquid crystal display device according to claim 21, further comprising: a backlight light source positioned on a lower side of the liquid crystal display panel in which the first substrate and the second substrate are bonded together; and a light source disposed under the liquid crystal display panel, To the light guide plate. The liquid crystal display according to claim 22, further comprising a reflector having a one-dimensional lattice array disposed under the light guide plate and converting the light of the S polarized component, which has not been selectively transmitted to the polarizing color filter, Device. The liquid crystal display device according to claim 23, wherein the reflection plate is made of a metallic thin film, or the surface layer of the reflection plate is coated with a conductive dielectric material or a metal. 24. The liquid crystal display according to claim 23, wherein the one-dimensional grating of the reflector is inclined at an angle within a range of +/- 30 DEG about 47.5 DEG with respect to the major axis direction of the slit of the polarizing color filter for polarization conversion. The liquid crystal display of claim 25, wherein the one-dimensional lattice has a triangular, semicircular, rectangular, or trapezoidal shape in cross section.

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