KR20120040868A - Liquid crystal display within a wire grid polarazer - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device having a wire grid polarizer, and more particularly, to a backlight unit emitting upward from a light source and a liquid crystal panel stacked on top of the backlight unit to form a pixel, on a lower substrate of the liquid crystal panel. Characterized in that it comprises a wire grid polarizer formed in the.
According to the present invention, a wire grid polarizer is directly formed on the TFT of the liquid crystal display device and the lower glass substrate on which the liquid crystal is formed, thereby realizing a reduction in production cost by removing the existing polarizing film and reducing the thickness of the entire device. It can be, and there is an effect that can improve the brightness.

Description

Liquid crystal display device {Liquid Crystal Display within a wire grid polarazer}

The present invention relates to a structure of a liquid crystal display device having a wire grid polarizer.

Liquid crystal displays (LCDs) are flat panel displays that are now widely used in mobile phones, laptops, monitors and TVs. A liquid crystal display is a device that transmits or blocks light by applying an electrical signal to each pixel in a liquid crystal panel positioned between two polarizers to change the arrangement of liquid crystals. Therefore, a separate light source is required to operate the liquid crystal display, and providing such a light source corresponds to a backlight unit.

1 is a conceptual view illustrating a general structure of a conventional liquid crystal display device, in which a liquid crystal panel A is disposed above the liquid crystal panel A, and a backlight unit B is disposed below the liquid crystal panel A. The liquid crystal LC is disposed between the substrate 9 and the lower substrate 6, and has a configuration including ITOs 7 and 8 for driving. Particularly, the upper part is a color filter and the lower part is a TFT array. Will be. The backlight unit is disposed below the liquid crystal panel and includes a light guide plate 2, a reflection sheet 1, a diffusion plate 3, and a reinforcing film (BEF) 4 to guide a light source upward.

In particular, polarizing films 5 and 10 may be provided on the lower surface of the lower substrate 6 constituting the TFT array of the liquid crystal panel and the upper surface of the upper substrate 9 constituting the color filter array to increase light transmittance. To make it work.

However, the conventional liquid crystal display device has a problem in that a manufacturing cost is increased because of the use of an expensive polarizing film and a slim liquid crystal display device due to the thickness of the polarizing film. In addition, the durability and heat resistance of the polarizing film is weak, there is a problem that the utilization of the manufacturing process of the liquid crystal display device is extremely limited, there is also a problem that decreases the brightness due to the use of the absorption type polarizing film.

The present invention has been made to solve the above-described problems, an object of the present invention is to form a wire grid polarizer directly on the lower glass substrate on which the liquid crystal display device TFT and the liquid crystal is formed, the production cost by removing the existing polarizing film The present invention provides a liquid crystal display device capable of reducing the thickness of the entire device and improving luminance.

As a means for solving the above problems, the present invention is a backlight unit that emits upward from the light source; A liquid crystal panel stacked on the backlight unit to form a pixel; It is possible to provide a liquid crystal display device comprising a; wire grid polarizer formed on the lower substrate of the liquid crystal panel.

The wire grid polarizer may include a first lattice layer having at least one first lattice pattern on the lower substrate, and at least one second lattice pattern formed on the first lattice pattern. Two lattice layers; As shown in FIG.

The second grid layer may further include a protective layer having a structure covering an upper portion of the second grid layer.

In addition, in the above-described structure, the first lattice layer may be formed of a polymer material having the same refractive index as the substrate.

The second grid pattern may be formed of any one metal selected from aluminum, chromium, silver, copper, nickel, and cobalt, or an alloy thereof.

In addition, the ratio of the width and height of the first grid pattern is preferably implemented to satisfy 1: (0.2 to 5), and the ratio of the width of the first grid pattern to the width of the second grid pattern is It is also possible to implement in the range of 1: (0.2 to 1.5). In this case, the width of the first lattice pattern may be implemented to satisfy a range of 10 nm to 200 nm and a height of 10 nm to 500 nm. Furthermore, the width of the second grid pattern may be implemented in 2 nm to 300 nm, and the period of the first grid pattern may be implemented in 100 nm to 250 nm.

According to the present invention, a wire grid polarizer is directly formed on the TFT of the liquid crystal display device and the lower glass substrate on which the liquid crystal is formed, thereby realizing a reduction in production cost by removing the existing polarizing film and reducing the thickness of the entire device. It can be, and there is an effect that can improve the brightness.

1 shows the structure and function of a conventional liquid crystal display.
2 is a schematic cross-sectional view showing the structure of a liquid crystal display device having a wire grid polarizer according to the present invention.
FIG. 3 is a conceptual view illustrating main parts of a wire grid polarizer according to the present invention in FIG. 2.
4 and 5 show another embodiment of the wire grid polarizer according to the present invention.
6 is a cross-sectional conceptual view showing the structure of a wire grid polarizer according to the present invention.
7 to 11 is a cross-sectional conceptual view showing a structure as another embodiment of the wire grid polarizer according to the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and operation according to the present invention. In the description with reference to the accompanying drawings, the same components are given the same reference numerals regardless of the reference numerals, and duplicate description thereof will be omitted. The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The present invention provides a technique for forming a wire grid polarizer directly on a lower glass substrate constituting a liquid crystal display device so that TFTs can be formed thereon, thereby making the overall liquid crystal panel thin and simultaneously improving luminance and reducing production cost. It is the summary to offer.

2 is a cross-sectional conceptual view showing the structure of a liquid crystal display device including a wire grid polarizer according to the present invention.

Referring to the drawings, a liquid crystal display according to the present invention comprises a backlight unit (B) that emits an upper portion emitted from a light source and a liquid crystal panel (A) stacked on the backlight unit to form a pixel. In particular, it is composed of a structure including a wire grid polarizer 100 formed on the lower substrate of the liquid crystal panel (A).

That is, the liquid crystal panel A according to the present invention has a technical point of implementing the wire grid polarizer according to the present invention directly on the lower glass substrate. And the TFT array 7 including ITO can be arrange | positioned on it. The color filter 8 and the liquid crystal LC are disposed under the upper glass 9, and a polarizing film may be added to the upper surface of the upper glass.

In addition, the backlight unit B under the liquid crystal panel A has a structure of a general backlight unit including a light guide plate 2, a diffusion plate 3, and various reinforcement films 4 for guiding a light source upward. Can be.

3 illustrates a structure of the wire grid polarizer 100 directly implemented on the upper portion of the lower glass substrate 110 of the liquid crystal panel in the above-described structure.

Referring to the illustrated structure, the wire grid polarizer 100 according to the present invention includes a first lattice layer 120 having at least one first lattice pattern 121 formed directly on the lower substrate 110 of the liquid crystal panel. ) May be implemented, and may include a second grid layer having at least one second grid pattern 130 formed of a metal material on the first grid pattern 121. Of course, the protective layer 140 may be further included on the second grid layer. When the protective layer is provided, the TFT array 7 may be provided on the top.

The substrate 110 may be a glass substrate used in a liquid crystal display, and the first lattice layer 120 stacked on the upper surface of the substrate 110 may be formed of a polymer material, and may be formed of a polymer material. The first grid pattern 121, which is a protrusion pattern having a predetermined period, is preferably formed on the surface of the first grid layer.

That is, the first lattice layer 120 is defined as including a layer including a plurality of first lattice patterns 121, which are protrusion patterns having a predetermined period, on the surface of the resin layer formed of a polymer. In particular, it is more preferred that the first grid layer 120 according to the present invention uses a material having the same refractive index as compared with the substrate 110. Of course, if necessary, the refractive index of the first lattice layer may be lower or higher than that of the substrate.

In addition, the first grid pattern 121 according to the present invention is preferably implemented so that the ratio of the width and height of the first grid pattern satisfies 1: (0.2 ~ 5), the width of the first grid pattern (w) is preferably implemented to satisfy the range of 10nm ~ 200nm, the height (h1) is 10nm ~ 500nm. In addition, the period of the first lattice pattern may be implemented in the range of 100nm ~ 250nm.

The second grid layer 130 collectively includes a structure including a plurality of second grid patterns 130, which are metal grid patterns formed on the first grid pattern 121, as one layer. It is defined as. The second grid pattern 130 has a structure in which the fine protrusion patterns of the metal material are arranged at regular intervals, and in particular, the second grid pattern 130 is a protrusion structure formed on the upper surface of the first grid pattern 121 by a process such as deposition. It can be formed using any one metal selected from aluminum, chromium, silver, copper, nickel, cobalt, or an alloy thereof. Here, the period means a distance between one metal grid pattern (second grid pattern) and a neighboring metal grid pattern (second grid pattern).

In addition, the shape of the cross-section of the second grid pattern 130 may have a variety of structures, such as square, triangle, semi-circular, etc., may have a metal line shape formed on a portion of the substrate patterned in the form of a triangle, square, sine wave, and the like. have. In other words, any one having a long line of metal line lattice having a certain period in one direction regardless of the cross-sectional structure may be used. In this case, the period may be less than half of the wavelength of light used, and thus the period may be formed in the range of 100 nm to 250 nm. In addition, in the preferred embodiment of the present invention can be implemented as 1: (0.5 ~ 1.5) of the ratio of the width and height of the second grid pattern 130. In particular, the ratio of the width of the first grid pattern and the width of the second grid pattern may be formed in the range of 1: (0.2 ~ 1.5), specifically, the width of the second grid pattern is 2nm ~ 300nm It can be implemented in a range.

Furthermore, in the wire grid polarizer according to the present invention, the transmittance can be adjusted according to the height and width of the two gratings (first and second grid patterns), respectively. If the width of the lattice is wider at the same pitch, the transmittance is lowered and the polarization extinction ratio is increased. In order to ensure maximum polarization efficiency, the polarization characteristic increases as the pitch decreases. As the height of the lattice increases, the polarization characteristic increases, and when the distance between the same lattice and the same lattice height is formed, the polarization characteristic improves as the width of the lattice increases. In this case, it is preferable to adjust the width of the first grid to have a width of (0.2 to 1.5) times the width of the second grid pattern in the present invention.

The wire grid polarizer according to the present invention as described above implements a structure of a unique wire grid polarizer directly on the lower glass substrate of the liquid crystal panel constituting the liquid crystal display device, thereby producing a cost of the liquid crystal display device by eliminating the existing polarizing film. It is possible to achieve the reduction of. In addition, since the occupational grid pattern is implemented on the lower substrate of the liquid crystal panel, the overall thickness of the equipment may be reduced, and the luminance may be improved compared to the existing polarizing film.

Hereinafter, various modifications of the wire grid polarizer according to the present invention formed on the above-described lower glass substrate will be described. The structure of the substrate 110 and the first and second lattice layers 120 and 130 which are basic structures are the same, and will be described with reference to a part that brings about additional deformation.

(1) Formation structure of blackening process layer

Another embodiment of the wire grid polarizer according to the present invention, provided with a metal grid pattern 130 formed on one surface or both surfaces of the lower glass substrate 110, the blackening formed on part or all of the metal grid pattern 130 It may be implemented in a structure for implementing a processing layer. Such a blackening layer can significantly reduce the surface re-reflection of the light flowing from the outside to enhance the contrast ratio, and can improve the readability.

The blackening layer may be implemented by basically blackening a part or all of the metal grid pattern 130 with an organic material or an inorganic material. That is, the blackening treatment in the preferred embodiment of the present invention means forming a cover film having a structure covering the surface of the metal grid pattern 130 by using an organic material or an inorganic material, and more preferably, due to the blackening treatment layer. The surface reflectance of the substrate can be made to be 40% or less.

As the organic material capable of performing the blackening treatment, a material containing chromium oxide or carbon may be used, and the inorganic material may be performed by an oxidation treatment process for copper. That is, in the case of inorganic materials, after copper is deposited on the metal lattice pattern described above, copper is etched to form only part or all of the copper on the metal lattice pattern, and then wet or dry metal oxidation (blackening) to blacken copper. It may be carried out in a process of advancing the process. Alternatively, the blackening layer may be formed by depositing chromium on the metal lattice pattern and etching to form part or all of the metal lattice pattern as described above.

(2) Formation structure of nano optical pattern under substrate

4 illustrates another embodiment of the wire grid polarizer according to the present invention. The first grid layer 120 and the first grid layer having at least one first grid pattern 121 on the substrate 110 are provided. The same configuration for implementing a second grid layer having at least one second grid pattern 130 formed on the grid pattern, but in particular a plurality of optical patterns formed on the rear surface of the lower glass substrate 110 It may be configured to include a polymer layer 140 having a (141). Since the polymer layer having the optical pattern is formed on the opposite side of the substrate on which the metal lattice pattern is formed, the optical loss is reduced when the light is incident, thereby increasing the amount of transmitted light, thereby making it possible to realize stable color coordinates.

In this case, the polymer layer 140 formed on the opposite surface on which the second grid pattern 130 of the substrate 110 is formed is preferably an optical pattern 141 implemented as a plurality of nano-sized nanopatterns. In this case, the polymer layer may use a UV resin or a thermosetting resin, but is not limited thereto, and a polymer resin having a good light transmittance may be applied.

The optical pattern formed on the surface of the polymer layer 140 may have a protrusion pattern protruding from the surface of the polymer layer uniformly or non-uniformly, such a protrusion pattern may be implemented in the range of 10nm ~ 200nm width. have. The optical pattern may have various shapes having a three-dimensional structure as a protruding pattern. For example, the shape of the vertical cross-section such as a cone, a cylinder, a prism, and a grating may be rectangular, triangular, or the like. It may have various structures such as semicircular.

In addition, the optical pattern may be formed by pressing using a mold in which the pattern is formed when the polymer layer is formed on the substrate. In addition, the polymer layer according to the present invention may be more preferably formed of a material having a lower refractive index than the substrate. As a result, the critical angle of the incident light L1 is increased to reduce the surface reflection of the incident surface, thereby improving the transmittance. The presence of the nanoscale optical pattern on the incident surface of the light increases the incident area of the light, thereby improving the transmittance. Effect can be realized. In addition, the presence of the polymer layer 140 may also be implemented to increase the scratch resistance of the substrate in parallel with the function of the protective film on the substrate 110.

(3) Formation structure of protective layer

In addition, unlike the above, as shown in FIG. 5, it may be implemented as an embodiment of forming the surface treatment layer 140 formed on the first grid pattern or the second grid pattern.

The surface treatment layer 140 may be formed on the first lattice pattern or the second lattice pattern, and the surface treatment layer may include an atmospheric pressure plasma treatment, a vacuum plasma treatment, a hydrogen peroxide solution treatment, and an oxidation accelerator to improve durability and strength. The surface treatment may be performed by any one method of treatment, corrosion inhibitor treatment, and self-assembly monolayer coating (SAM coating).

In particular, as shown in FIG. 2, when forming the surface treatment layer including the entirety of the second grid pattern and the close contact portion of the first grid pattern and the second grid pattern, the surface of each grid pattern is formed on the surface of each grid pattern. By providing an oxide film or similar surface treatment film to improve durability without deformation, it is possible to implement physical properties to improve adhesion between the second grid pattern and the polymer layer of the first grid pattern without deteriorating optical properties.

(4) Multi-layer structure of light absorbing layer

The wire grid polarizer according to the present invention is formed of a metal material on the first grid layer 120 and the first grid pattern 121 having at least one first grid pattern 121 on the substrate 110. It is also possible to implement a structure including a second lattice layer having at least one or more second lattice patterns 130, and a light absorbing layer (A) stacked on the second lattice layer to absorb light introduced from the outside. Do.

The second grid pattern 121 is made of a metal material is made of a metal material with a high reflectance, so that the light can be recycled by increasing the reflection efficiency of the light, the light absorption layer (Q) to receive light from the outside By performing the function of absorbing it is possible to implement the brightness enhancement.

Light absorbing layer (Q) is implemented on the second grid pattern to perform the function of absorbing light from the outside, its structure can be implemented in a variety of shapes. As shown in FIG. 5, the light absorption layer Q is disposed on the first absorption grid pattern 140 and the first absorption grid pattern 140 formed on the second grid pattern 130. It may be formed of a laminated structure of the third grid pattern 150 of the metal material to be formed, and the second absorption grid pattern 160 formed on the third grid pattern. This can absorb the light from the outside. In particular, the first and second absorption type grating patterns may be formed using transparent metal oxides such as SiO ₂ , MgO ₂ , CeO ₂ , ZrO ₂ , ZnO, ITO, and the like to improve light absorption efficiency. The grid pattern 150 may be provided as a metal material. The third grid pattern 150 is any one metal selected from aluminum (Al), chromium (Cr), silver (Ag), copper (Cu), nickel (Ni), cobalt (Co), and molybdenum (Mo). Or it can form using these alloys. In this case, the thickness h1 of the first absorption grating pattern 140 is 50 nm to 300 nm, and the thickness of the third lattice pattern 150 is 1 nm to 20 nm, and the second absorption grating pattern 160 is It can be implemented with a thickness (h2) in the range of 50nm ~ 500nm.

Of course, the structure of forming the light absorbing layer may be modified in various structures as shown in FIGS. 7 to 11.

For example, as shown in FIG. 7, instead of the pattern structure formed on the second grid pattern 130, the second absorption pattern lattice layer 170 has a structure for implementing a single absorption layer. Can be formed. Such a structure is formed by depositing a structure covering the entire second lattice layer instead of the second absorptive lattice pattern 140 described above, and the second absorptive lattice layer 170 absorbs light. In addition to the function to be able to implement the advantage that can simultaneously implement the protective layer of the entire wire grid polarizer.

Alternatively, as in the implementation structure of FIGS. 8 and 9, the structure of the wire grid polarizer of FIG. 6 may further include a functional film 180 on the second absorption type grid pattern 160, or as illustrated in FIG. 9. As shown in FIG. 7, the second absorption band lattice layer 170 of the wire grid polarizer may further include a functional film 180. The functional film 180 is disposed on the light absorbing layer (Q) according to the present invention to implement a viewing angle compensation or a special color coordinate stability, for this purpose, the compensation film (COP, TAC, PC substrate) through a lamination method It can be formed.

Alternatively, the wire grid polarizer having the structure shown in FIGS. 10 and 11 may be implemented.

Referring to FIG. 10, this is a first lattice layer 120 having at least one first lattice pattern 121 on a substrate 110, and an absorption type lattice pattern formed on the first lattice pattern 121. Light absorbing layer (Q) having a structure is implemented, it may be implemented in a structure including a second grid layer 130 having at least one or more second grid pattern formed of a metal material on the light absorbing layer (Q). . That is, the structure of the second lattice layer 130 in FIG. 6 or 7 may be modified to a structure in which it is disposed at the top.

The light absorbing layer Q is formed of a first lattice pattern 140 formed on the first lattice pattern 121 and a third lattice of metal material formed on the first absorptive lattice pattern 140. The pattern 150 and the second absorption grid pattern 160 formed on the third grid pattern may be formed in a stacked structure. This can absorb the light from the outside. In particular, the first and second absorption type grating patterns may be formed using a transparent metal oxide such as SiO _2, and the third grid pattern 150 may be formed of a metal material to improve light absorption efficiency. .

That is, the third grid pattern 150 is any one selected from aluminum (Al), chromium (Cr), silver (Ag), copper (Cu), nickel (Ni), cobalt (Co), and molybdenum (Mo). It can be formed using a metal or an alloy thereof. In this case, the thickness of the first absorption grating pattern 140 is 50 nm to 300 nm, the thickness of the third lattice pattern 150 is 1 nm to 20 nm, and the second absorption grating pattern 160 is 50 nm to 500 nm. It can be implemented in the thickness of the range as described above, and other configurations, such as the adjustment of the standard of the first grid pattern and the second grid pattern can be applied to the same materials and standards as described in FIG.

FIG. 11 may protect the second grid pattern 130 as a metal pattern by forming a protective layer including an oxide layer or a polymer resin on the second grid pattern 130 in the structure of FIG. 10. .

In the foregoing detailed description of the present invention, specific examples have been described. However, various modifications are possible within the scope of the present invention. The technical idea of the present invention should not be limited to the embodiments of the present invention but should be determined by the equivalents of the claims and the claims.

1: reflective sheet
2: light guide plate
3: diffuser plate
4: BEF
5, 10: polarizing film
6, 9: glass substrate
7: TFT array
8: C / F
100: wire grid polarizer
110: lower substrate
120: first lattice layer
121: first grid pattern
130: second grid pattern
140: protective layer, blackening layer, surface treatment layer, polymer material layer, the first absorption grating pattern
150: third grid pattern
160: second absorption grating pattern
170: second absorption grating layer
180: functional film
190: protective film

Claims (17)

A backlight unit emitting upward from the light source;
A liquid crystal panel stacked on the backlight unit to form a pixel;
A wire grid polarizer having a grating layer having a plurality of grating patterns directly formed on an upper surface or a bottom surface of a lower substrate of the liquid crystal panel;
And the liquid crystal display device.
The method according to claim 1,
The wire grid polarizer,
A first lattice layer having at least one first lattice pattern on the lower substrate; and
A second grid layer having at least one second grid pattern formed on the first grid pattern;
Liquid crystal display comprising a.
The method according to claim 2,
The second grid layer,
And a protective layer further covering the upper portion of the second grid layer.
The method according to any one of claims 1 to 3,
And the first lattice layer is formed of the same polymer material as the refractive index of the substrate.
The method of claim 4,
The second grid pattern is,
Liquid crystal display device formed of any one metal selected from aluminum, chromium, silver, copper, nickel, cobalt or alloys thereof.
The method of claim 4,
A liquid crystal display device in which a ratio of width and height of the first grid pattern satisfies 1: (0.2 to 5).
The method of claim 6,
The ratio of the width of the first grid pattern and the width of the second grid pattern is 1: (0.2 ~ 1.5).
The method of claim 6,
The first lattice pattern has a width of 10nm ~ 200nm, the height of the liquid crystal display device satisfying the range of 10nm ~ 500nm.
The method according to claim 8,
The width of the second grid pattern is a liquid crystal display device 2nm ~ 300nm.
The method according to claim 8,
The period of the first grid pattern is a liquid crystal display device 100nm ~ 250nm.
The method according to claim 1,
And a polymer layer having a plurality of optical patterns formed on the rear surface of the substrate.
The method according to claim 2,
And a surface treatment layer formed on the first grid pattern or the second grid pattern of the wire grid polarizer.
The method according to claim 2,
And a blackening layer formed on part or all of the first grid pattern of the wire grid polarizer.
The method according to claim 2,
The wire grid polarizer,
A light absorbing layer stacked on the second grid layer to absorb light introduced from the outside;
Liquid crystal display device further comprises.
The method according to claim 14,
The light absorption layer,
A first absorption grid pattern formed on the second grid pattern; and
A third grid pattern of metal material formed on the first absorption grid pattern;
A second absorption grating pattern formed on the third grating pattern;
Liquid crystal display device comprising a structure.
The method according to claim 14,
The light absorption layer,
A first absorption grid pattern formed on the second grid pattern; and
A third grid pattern of metal material formed on the first absorption grid pattern;
A second absorption grating layer formed on the third grid pattern;
Liquid crystal display device having a structure having.
The method according to claim 1,
The wire grid polarizer,
A first grid layer having at least one first grid pattern on the substrate;
A light absorption layer having an absorption type grid pattern formed on the first grid pattern;
And a second lattice layer having at least one second lattice pattern formed of a metal material on the absorption type lattice pattern.

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