KR20120040869A - A wire grid polarazer and liquid crystal display within the same - Google Patents

Abstract

PURPOSE: A wire grid polarizer and a liquid crystal display device including the same are provided to minimize color change rate according of an observation angle by controlling the transmittance of each wavelength according to the optical angle of incident light. CONSTITUTION: A first grid layer(120) comprises one or more first grid patterns(121) on a substrate(110). The second grid layer comprises one or more second grid patterns formed of metal material on the top of the first grid pattern. A light absorption layer is laminated on the second grid layer and absorbs the light from the outside.

Description

Wire grid polarizer and liquid crystal display including the same {A Wire Grid Polarazer and Liquid Crystal Display within the same}

The present invention relates to a wire grid polarizer for implementing luminance enhancement and a structure of a liquid crystal display device having the same.

In general, a polarizer or a polarizer refers to an optical device that derives linearly polarized light having a specific vibration direction among unpolarized light such as natural light. One of the optical devices, a wire grid polarizer, is an optical device that generates polarized light using a conductive wire grid. Since it has higher polarization separation performance than other polarizers, it has long been used as a reflective polarizer useful in the wavelength range of the infrared region.

1 illustrates a structure and a function of a conventional wire grid polarizer, and has a structure in which a metal grid 2 having a predetermined thickness h disposed at a predetermined period A is arranged on a substrate 1. In particular, the period of the fine metal lattice of the wire grid polarizer is manufactured to less than half of the visible light wavelength. Such a wire grid polarizer is a component having a vector orthogonal to the conductive wire grid when the light in the non-polarization state is incident when the wavelength of the incident light is sufficiently smaller, that is, a component having a vector that transmits and is parallel to the wire grid. S polarized light is reflected.

Conventional wire gird polarizers (WGP) have a nano-grade lattice structure on the surface of the substrate, which has only one side of the adhesive surface to the substrate, and the durability of the metal wire lattice is low due to the low adhesion and hardness of the metal wire lattice. . Furthermore, this problem is applied to the product as a physically weak point such as the metal grid collapses or scratches during the assembly process or use, resulting in a decrease in the reliability of the entire product.

Conventionally, in order to compensate for these physical problems, conventional technologies mainly use expensive metal materials to protect the metal line gratings, but this increases the manufacturing cost due to the high price of the metal materials, and reduces the productivity. Will be generated. In addition, when the protective layer is formed to protect the metal grid, a problem of deterioration or change of optical properties occurs.

In addition, the conventional wire grid polarizer is generally used as a reflective polarizer using aluminum metal, and is applied to the liquid crystal display device to implement a brightness enhancement effect. However, in the case of the conventional wire grid polarizer, the light passing through is re-reflected from the glass, or the incoming light is reflected back by the reflective wire grid polarizer, thereby reducing the contrast, thereby replacing the existing absorption polarizing film. In the following, there is a difficulty in using the liquid crystal display. In addition, the currently commercially available brightness enhancement polarizing film (trade name: DBEF-P) is used by attaching the fabric of the dual brightness enhancement film (DBEF) to the absorption type polarizing film by means of a lining method, which is thick and sold at a very high cost. It also has many problems in reliability.

The present invention has been made to solve the above problems, an object of the present invention is to implement a brightness enhancement without lowering the contrast contrast through a wire grid polarizer having an absorption function and a reflection function, an insulating agent formed on a substrate The present invention provides a wire grid polarizer capable of minimizing color change according to an observation angle by controlling a transmittance of each wavelength according to a light angle of incident light by implementing a single grid pattern and a metal grid pattern thereon.

As a means for solving the above problems, the present invention is a first lattice layer having at least one first lattice pattern on the substrate; A second grid layer having at least one second grid pattern formed of a metal material on the first grid pattern; And a light absorbing layer stacked on the second lattice layer to absorb light introduced from the outside, thereby providing a wire grid polarizer.

The light absorption layer may include: a first absorption grid pattern formed on the second grid pattern; and a third grid pattern formed of a metal material on the first absorption grid pattern; And a second absorption type grid pattern formed on the third grid pattern.

Alternatively, the light absorption layer according to the present invention may include a first absorption grid pattern formed on the second grid pattern; and a third grid pattern formed of a metal material on the first absorption grid pattern; The second absorption type grating layer formed on the pattern; may be implemented as a structure having a.

In the wire grid polarizer according to the present invention, the first and second absorption grating patterns and the second absorption grating layer may be formed using a metal oxide of a transparent material.

Furthermore, the thickness of the first absorption grating pattern may be implemented in a range of 50 nm to 300 nm, and the thickness of the third lattice pattern may be 1 nm to 20 nm.

Alternatively, the second absorption grating pattern and the second absorption grating layer may have a thickness in the range of 50 nm to 500 nm.

The first grid layer of the wire grid polarizer according to the present invention may be formed of a polymer material having the same refractive index as the substrate, and the second grid layer, the third metal layer, or the third grid pattern may include aluminum, chromium, It may be formed of any one metal selected from silver, copper, nickel, cobalt, or an alloy thereof.

In addition, the wire grid polarizer according to the present invention may be implemented as a structure further comprising a functional film for implementing viewing angle compensation stacked on the light absorbing layer.

Further, in the present invention, the ratio of the width and height of the first grid pattern satisfies 1: (0.2 to 5), or the ratio of the width of the first grid pattern and the width of the second grid pattern is 1 :( 0.2 to 1.5).

Alternatively, the width of the first lattice pattern is within the range of 10nm ~ 200nm, the height is 10nm ~ 500nm, or the width of the second lattice pattern is 25nm ~ 200nm, the period of the first lattice pattern is in the range of 50nm ~ 400nm Can be implemented.

Unlike the above-described structure, the wire grid polarizer according to the present invention comprises: a first lattice layer having at least one first lattice pattern on a substrate; A light absorption layer having an absorption type grid pattern formed on the first grid pattern; It is also possible to implement a structure including a; a second grid layer having at least one second grid pattern formed of a metal material on the absorption grid pattern. In this case, the light absorption layer may be implemented in a structure in which a third metal layer is formed inside the absorption grid pattern, and may further include a protective layer stacked on the second grid layer.

The wire grid polarizer according to the present invention described above includes a backlight unit that emits upward from the light source; In the liquid crystal display device comprising a liquid crystal panel stacked on top of the backlight unit to form a pixel, it is disposed on the upper or lower portion of the liquid crystal panel to improve the brightness of the liquid crystal display device.

According to the present invention, it is possible to implement brightness enhancement without deteriorating bright room contrast through a wire grid polarizer having both absorption and reflection functions.

In addition, according to the present invention, by implementing an insulating first grid pattern formed on the substrate and a metal grid pattern thereon, by controlling the transmittance of each wavelength according to the light angle of the incident light to minimize the color change rate according to the viewing angle The advantage of providing a grid polarizer is also realized.

1 is a conceptual diagram showing the structure of a conventional wire grid polarizer.
2 is a cross-sectional conceptual view showing the structure of a wire grid polarizer according to the present invention.
3 to 7 is a cross-sectional conceptual view showing a structure as another embodiment of the wire grid polarizer according to the present invention.
8 is a conceptual diagram illustrating an embodiment of a liquid crystal display device employing a 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 is to provide a wire grid polarizer capable of improving the luminance without deterioration of the contrast by implementing a wire grid polarizer having an absorption function and a reflection function at the same time.

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

1. Wire Grid Polarizer Basic Structure

Referring to the drawings, the wire grid polarizer according to the present invention includes a first grid layer 120 and the first grid pattern 121 having at least one first grid pattern 121 on the substrate 110. A second grid layer having at least one second grid pattern 130 formed of a metallic material on top of the second grid layer, and a light absorption layer A stacked on the second grid layer to absorb light introduced from the outside; It is configured by. In particular, the second grid pattern 121 is made of a metal material is made of a metal material having a high reflectance to increase the reflection efficiency of the light to recycle 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.

Specifically, the substrate 110 is used as a support, a glass substrate capable of transmitting visible light, and various polymers such as quartz, acryl, TAC, COP, PC, PET, and the like may be used. In particular, in the present invention, it is more preferable to be able to process in a continuous process through a process using an optical film substrate having a certain degree of flexibility.

The first lattice layer 120 is formed in close contact with the upper surface of the substrate 110, the material may be implemented as a resin layer made of a polymer material, in particular, the surface of the first lattice pattern (a certain protrusion pattern) It is preferable to have many 121). That is, the first lattice layer 120 is defined as including a layer provided with 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. The first grid layer 120 may be formed by implementing a pattern by an imprinting method using a mold. In particular, the first lattice layer 120 according to the present invention is more preferably used to improve the utilization efficiency of light by using a material having a lower refractive index or the same or higher than the substrate 110 according to the purpose. .

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 may be formed using any one metal selected from aluminum (Al), chromium (Cr), silver (Ag), copper (Cu), nickel (Ni), cobalt (Co), and molybdenum (Mo) or an alloy thereof. Can be. In particular, the method of forming the second lattice pattern may be implemented by a deposition method such as sputtering, chemical vapor deposition, or an evaporator. Here, the period refers to a distance between one lattice pattern (eg, the second lattice pattern) and a neighboring lattice pattern (eg, the second lattice pattern). In particular, the second grid layer is implemented by the second grid pattern 130 made of a metal material, and reflects light to recycle light, thereby performing a function of increasing brightness. 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 the light used, and thus the period may be formed in the range of 50 nm to 400 nm, and more preferably in the range of 50 nm to 200 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 metal grid pattern 130. 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. In addition, the width of the first grid pattern or the second grid pattern may be implemented in the range of 25nm ~ 200nm.

In addition, the light absorption 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 various shapes. As shown in FIG. 2, 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.

2. Second Implementation

The structure of the wire grid polarizer according to the present invention shown in FIG. 2 is different from the structure of the light absorption layer Q.

Referring to FIG. 3, a first absorption grid pattern 140 formed on the first grid layer 120, the second grid pattern 130, and the second grid pattern 130 on the substrate 110. And a structure in which the third grid pattern 150 of the metal material formed on the first absorption grid pattern 140 is the same as the structure of FIG. 2, but is not a pattern structure formed on the metal grid pattern. It may be modified to form a structure having a second absorption type lattice layer 170 of a structure for implementing one layer. That is, other than the shape of the second absorptive lattice layer 170, the technical configuration such as the material, numerical limitation, and cycle described in FIG. 2 may be applied to the second embodiment in the same manner. In addition, when the thickness h1 of the first absorption grating pattern 140 is 50 nm to 300 nm, and the thickness of the third grating pattern 150 is 1 nm to 20 nm, the second absorption grating layer 170 is also formed. It is preferable to implement with a thickness (h2) in the range of 50nm ~ 500nm.

That is, there is a difference in that the second absorption grating pattern 140 in FIG. 2 is implemented as the second absorption grating layer 170. 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.

3. Third and fourth implementation

Another embodiment of the wire grid polarizer according to the present invention described in FIGS. 2 and 3 will be described with reference to FIGS. 4 and 5.

In the present exemplary embodiment, the structure of the wire grid polarizer of FIG. 2 may further include a functional film 180 on the second absorption type grid pattern 160, or as shown in FIG. 5. The second absorption type grating layer 170 may be formed in a structure including a functional film 180 further.

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.

4. Fifth and Sixth Examples

Hereinafter, another embodiment of implementing the wire grid polarizer according to the present invention will be described with reference to FIGS. 6 and 7.

Referring to FIG. 6, 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 grid layer 130 in FIG. 2 or FIG. 3 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. 7 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. 6. .

The wire grid polarizer of various structures according to the present invention described with reference to FIGS. 2 to 7 described above may be applied to a liquid crystal display to simultaneously realize an absorption function and a reflection function without improving contrast.

8 illustrates an embodiment of a liquid crystal display including a wire grid polarizer according to the present invention.

That is, referring to the drawing shown, the backlight unit (B) that emits from the light source and the liquid crystal panel (A) stacked on top of the backlight unit to form a pixel, in particular, the liquid crystal panel The wire grid polarizers 100 and 200 according to the present invention may be configured on the upper or lower substrate of (A).

The liquid crystal panel A is implemented in a structure in which the wire grid polarizer according to the present invention is disposed on the upper glass substrate 8 or the lower glass substrate 5. The TFT array 6 including ITO may be disposed on the lower glass substrate. The color filter 7 and the liquid crystal LC may be disposed below the upper glass substrate 8.

In addition, the backlight unit B disposed below the liquid crystal panel A may include a light guide plate or a diffuser plate 2 for guiding the light source L upwards, and various backlight sheets 4. The structure can be implemented.

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.

100, 200: wire grid polarizer
110: lower substrate
120: first lattice layer
121: first grid pattern
130: second grid pattern
140: first absorption grating pattern
150: third grid pattern
160: second absorption grating pattern
170: second absorption grating layer
180: functional film
190: protective film
A: liquid crystal panel
B: backlight unit

Claims (18)

A first grid layer having at least one first grid pattern on the substrate;
A second grid layer having at least one second grid pattern formed of a metal material on the first grid pattern;
A light absorbing layer stacked on the second grid layer to absorb light introduced from the outside;
Wire grid polarizer is configured to include.
The method according to claim 1,
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;
Wire grid polarizer having a structure comprising a.
The method according to claim 2,
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;
Wire grid polarizer having a structure having a.
The method according to claim 2 or 3,
The first and second absorption grating pattern and the second absorption grating layer,
Wire grid polarizer composed of transparent metal oxide.
The method of claim 4,
The thickness of the first absorption type grid pattern is 50nm ~ 300nm, the thickness of the third grid pattern is a wire grid polarizer of 1nm ~ 20nm.
The method according to claim 5,
The second absorption grating pattern and the second absorption grating layer is a wire grid polarizer formed to a thickness in the range of 50nm ~ 500nm.
The method of claim 4,
The first grid layer is a wire grid polarizer formed of a polymer material having the same refractive index as the substrate.
The method of claim 4,
The second grid layer, the third metal layer or the third grid pattern,
A wire grid polarizer formed of any one metal selected from aluminum, chromium, silver, copper, nickel, cobalt or alloys thereof.
The method of claim 4,
Wire grid polarizer further comprising a functional film for implementing a viewing angle compensation stacked on top of the light absorption layer.
The method of claim 4,
A wire grid polarizer in which the ratio of the width and height of the first grid pattern satisfies 1: (0.2 to 5).
The method according to claim 10,
The ratio of the width of the first grid pattern and the width of the second grid pattern is 1: (0.2 ~ 1.5) wire grid polarizer.
The method of claim 11,
A wire grid polarizer satisfying a range of 10 nm to 200 nm and a height of 10 nm to 500 nm of the first grid pattern.
The method of claim 12,
The width of the second grid pattern is a wire grid polarizer of 25nm ~ 200nm.
The method of claim 4,
The period of the first grid pattern is a wire grid polarizer of 50nm ~ 400nm.
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;
A second grid layer having at least one second grid pattern formed of a metallic material on the absorption grid pattern;
Wire grid polarizer comprising a.
The method according to claim 15,
The light absorption layer,
Wire grid polarizer implemented in a structure in which a third metal layer is formed inside the absorption grid pattern.
The method according to claim 16,
The wire grid polarizer further comprises a protective layer stacked on the second grid layer.
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 of claim 1 or 15 disposed above or below the liquid crystal panel;
And the liquid crystal display device.

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