KR20160112380A

KR20160112380A - Liquid crystal panel and liquid crystal display devices comprising the same

Info

Publication number: KR20160112380A
Application number: KR1020150038032A
Authority: KR
Inventors: 송제훈
Original assignee: 동우 화인켐 주식회사
Priority date: 2015-03-19
Filing date: 2015-03-19
Publication date: 2016-09-28

Abstract

The present invention relates to a liquid crystal panel and a liquid crystal display device having the same, and more particularly, to a liquid crystal panel including a top plate polarizer and a bottom plate polarizer arranged such that their absorption axes are parallel to each other, and a liquid crystal cell disposed between the top plate polarizer and the bottom plate polarizer And a polarizing rotation layer, a negative B-plate, and a negative C-plate having specific optical characteristics between the upper polarizer and the lower polarizer, thereby significantly improving the visibility, and a liquid crystal display having the liquid crystal panel .

Description

TECHNICAL FIELD [0001] The present invention relates to a liquid crystal panel and a liquid crystal display device having the liquid crystal panel.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal panel and a liquid crystal display device having the same, and more particularly, to a liquid crystal panel having improved visual characteristics and a liquid crystal display device having the same.

1, a liquid crystal display device (LCD) is a liquid crystal display device (LCD) in which a top plate polarizing plate 20 and a bottom plate polarizing plate 30 are bonded to the liquid crystal cell 10 on the viewer side and the backlight unit side, .

A typical polarizing plate is composed of a polyvinyl alcohol (PVA) polarizer and a polarizer protective film laminated on at least one side of the polarizer, and is bonded to the liquid crystal cell by a pressure-sensitive adhesive layer. At this time, a polarizing plate having the same configuration as the upper plate polarizer and the lower plate polarizer can be bonded to both sides of the liquid crystal cell.

Normally, the polarizers of the upper plate polarizer and the lower plate polarizer are arranged in Cross-Nicol. For example, in the case of a normally black mode liquid crystal panel such as a VA (Vertical Alignment) mode or an IPS (In-Plane Switching) mode, the polarizer of the upper plate polarizer has its absorption axis direction and the polarizer of the lower plate polarizer, Are arranged to be orthogonal to each other.

However, in recent trends toward larger-sized display devices, it is difficult to manufacture a large polarizer whose absorption axis is vertical due to limitation of the original width of the polarizer.

Further, in the liquid crystal panel, there arises a problem that the optical films disposed on both sides of the liquid crystal cell shrink or expand due to changes in temperature and humidity in use. When the optical film shrinks or expands, there is a problem that the liquid crystal cell adhered to the optical film is bent, thereby causing light leakage.

In this regard, Japanese Patent Application Laid-Open No. 2002-207211 discloses that the thickness of the viewer-side polarizing plate having a transparent protective layer on the polyvinyl alcohol polarizing film and the thickness of the polarizing plate on the back side are set to a predetermined relationship, A liquid crystal display device is disclosed.

Korean Patent Laid-Open Publication No. 2003-0087893 discloses a liquid crystal panel including a polarizing plate having the same shrinkage force as a pressure-sensitive adhesive for bonding to a liquid crystal cell including a pressure-sensitive adhesive having different strengths. Discloses a liquid crystal display device including a top plate polarizer and a bottom plate polarizer, each of which is bonded to a liquid crystal cell by a pressure sensitive adhesive layer having a different shrinkage amount.

However, with the recent enlargement of the liquid crystal panel, the problem of bending of the liquid crystal panel due to elongation and contraction of an optical film such as a polarizing plate becomes more important and has not been sufficiently solved yet.

Patent Document 1: JP-A-2002-207211 Patent Document 2: Korean Patent Publication No. 2003-0087893 Patent Document 3: Korean Patent Publication No. 2005-0080504

It is another object of the present invention to provide a liquid crystal display device having improved visibility characteristics with improved front and slope contrast ratio.

1. A liquid crystal display comprising: a top plate polarizer and a bottom plate polarizer arranged such that their absorption axes are parallel to each other; and a liquid crystal cell disposed between the top plate polarizer and the bottom plate polarizer,

A polarizing rotation layer, a negative B-plate, and a negative C-plate disposed between the upper plate polarizer and the lower plate polarizer,

Wherein the polarizing rotating layer rotates the linearly polarized light by 85 ° to 95 °, and the wavelength dispersion characteristic is inversely dispersed,

The negative B-plate satisfies the following formula (1)

Wherein the negative C-plate satisfies the following formula (2): < EMI ID =

[Equation 1]

0.00041 * Ro ² - 0.12315 * Ro + 10.17798? Nz? 0.00041 * Ro ² - 0.12315 * Ro + 10.37798

&Quot; (2) "

-55.3375 * (Nz value of B-plate) + 434.2867? Rth? -82.5740 * (Nz value of B-plate) + 307.5324

(Wherein Ro of the negative B-plate is 50 to 150 nm).

2. The liquid crystal panel according to 1 above, wherein the negative C-plate satisfies the following formula (3)

&Quot; (3) "

-82.5740 * (Nz value of B-plate) + 414.2867? Rth? -82.5740 (Nz value of B-plate) + 434.2867.

3. The liquid crystal panel of claim 1, wherein the negative C-plate satisfies the following formula (4)

&Quot; (4) "

-55.3375 * (Nz value of B-plate) + 307.5324? Rth? -55.3375 * (Nz value of B-plate) + 327.5324.

4. The liquid crystal panel according to 1 above, wherein the wavelength dispersion characteristics of the polarizing rotating layer are Ro (450) / Ro (550) = 0.78 to 0.86 and Ro (650) / Ro (550) = 1.14 to 1.22.

5. The liquid crystal panel as in 1 above, wherein the polarization rotation layer is formed as a single layer or a half-wave plate (half-wave plate) of two layers.

6. The polarizing plate of claim 1, wherein the polarization rotation layer is formed of a half-wave plate (half-wave plate) of two layers, the optical axis of each half-wave plate forms an angle of 20 to 40 And 60 [deg.] To 80 [deg.].

7. The polarizing plate of claim 1, wherein the polarization rotation layer is formed of a half wave plate (half wave plate) of two layers, and one of the half wave plates is Ro (450) / Ro (550) = 0.78 to 0.86 and Ro 650) / Ro (550) = 1.14 to 1.22.

8. The liquid crystal panel of 1 above, wherein the polarizing rotating layer is bonded to one surface of the upper polarizer or the lower polarizer of the liquid crystal cell.

9. The liquid crystal panel according to 1 above, wherein the polarization rotation layer is bonded to one surface of the polarizer of the upper plate polarizer or the lower plate polarizer, which is the liquid crystal cell side.

10. The liquid crystal panel according to item 1 above, wherein the negative B-plate is bonded to one surface of the polarizer of the upper plate polarizer or the lower plate polarizer.

11. The liquid crystal panel as in 1 above, wherein the Nz of the negative C-plate is 20 or more.

12. The liquid crystal panel according to 1 above, wherein the negative C-plate is bonded to one surface of the polarizer of the upper plate polarizer or the lower plate polarizer.

13. The liquid crystal panel of claim 1, wherein the negative B-plate is bonded to one side of the liquid crystal cell side of the upper plate polarizer or the upper plate polarizer, and the negative C-plate is bonded to one side of the lower plate polarizer or the lower plate polarizer.

14. The liquid crystal panel of 1 above, wherein said liquid crystal cell is a vertically aligned liquid crystal mode.

15. A liquid crystal display device comprising the liquid crystal panel according to any one of 1 to 14 above.

In the liquid crystal display device of the present invention, the absorption axes of the upper polarizer and the lower polarizer are arranged in parallel so that the upper polarizer and the lower polarizer shrink or expand in the same direction so that the stress applied to the liquid crystal cell is the same on both sides, It is possible to prevent the panel from warping.

Further, the liquid crystal display device of the present invention includes a polarization rotation layer that rotates linearly polarized light by about 90 degrees, thereby effectively implementing an image display function of the liquid crystal panel.

Further, the liquid crystal display device of the present invention can further improve the slope contrast ratio by providing the optical compensation layer having specific optical characteristics.

Further, since the polarizing rotating layer of the liquid crystal display of the present invention has the wavelength characteristic of inverse dispersion, the front contrast ratio and the slope contrast ratio can be improved, and thus the viewing characteristic is excellent.

1 is a cross-sectional view schematically showing a conventional liquid crystal panel.
2 is a cross-sectional view schematically showing one embodiment of the liquid crystal panel of the present invention.
3 is a diagram showing the relationship of the directions (x, y, z) of the refractive indexes (nx, ny, nz).

The present invention relates to a liquid crystal panel and a liquid crystal display device having the same, and more particularly, to a liquid crystal panel including a top plate polarizer and a bottom plate polarizer arranged such that their absorption axes are parallel to each other, and a liquid crystal cell disposed between the top plate polarizer and the bottom plate polarizer And a polarizing rotation layer, a negative B-plate, and a negative C-plate having specific optical characteristics between the upper polarizer and the lower polarizer, thereby significantly improving the viewing characteristic and a liquid crystal display device having the same .

Hereinafter, the present invention will be described in detail with reference to the drawings. It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. And shall not be construed as limited to such matters.

Fig. 2 schematically shows an embodiment of the liquid crystal panel of the present invention. The liquid crystal panel of the present invention includes a liquid crystal cell 10 and a top plate polarizer 200 on the viewer side and a bottom plate polarizer 300 on the backlight unit side relative to the liquid crystal cell 10, A polarizing rotation layer 400 disposed between the polarizing plates 300, a negative B-plate 500, and a negative C-plate 600.

Polarizer

The upper plate polarizer 200 and the lower plate polarizer 300 according to the present invention are arranged such that the absorption axes of the respective polarizers are parallel to each other. Therefore, the upper plate polarizer and the lower plate polarizer contract or expand in the same direction, so that the stress applied to the liquid crystal cell becomes the same on both sides, and warping of the liquid crystal panel can be prevented. Further, even when the polarizer is manufactured, the influence of the restriction due to the original width can be reduced.

The upper plate polarizer 200 and the lower plate polarizer 300 may be a single layer of a polarizer or a laminate in which a protective film is laminated on at least one surface of a polarizer.

Polarizers of the polarizers 200 and 300 can be applied without any particular limitation as those used in the art. For example, a polarizer is one in which a dichroic dye is adsorbed and oriented on a stretched polymer film.

The polymer film constituting the polarizer is not particularly limited as long as it is a film which can be dyed with a dichroic substance such as iodine. Specifically, the polymer film may be a polyvinyl alcohol film, an ethylene-vinyl acetate copolymer film, an ethylene-vinyl alcohol copolymer film , Cellulose films, partially saponified films thereof, and the like; A polyvinyl alcohol film, a dehydrated polyvinyl alcohol film, and a dehydrochlorinated acid-treated polyvinyl alcohol film; And the like. Of these, a polyvinyl alcohol-based film is preferable because it has an excellent effect of enhancing the uniformity of the degree of polarization in the plane and is excellent in dye affinity for a dichroic substance.

More preferably, it may be a polyvinyl alcohol-based film obtained by saponifying a polyvinyl acetate resin. Examples of the polyvinyl acetate resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Other monomers copolymerizable with vinyl acetate include acrylamide monomers having an unsaturated carboxylic acid type, an unsaturated sulfonic acid type, an olefin type, a vinyl ether type, and an ammonium group.

The polyvinyl alcohol resin may also be modified. For example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The saponification degree of the polyvinyl alcohol-based resin is usually 85 to 100 mol%, preferably 98 mol% or more. The polymerization degree of the polyvinyl alcohol-based resin is usually 1,000 to 10,000, preferably 1,500 to 5,000.

Such a polyvinyl alcohol-based resin film is used as the original film of the polarizer. The method of forming the film of the polyvinyl alcohol-based resin is not particularly limited, and a known method can be used. The thickness of the original film is not particularly limited, and may be, for example, 10 to 150 mu m.

The polarizer is produced by using a disc method using a known method. For example, swelling, dyeing, crosslinking, stretching, and the like. The order and the number of the steps are not particularly limited. The final draw ratio is about 4.5 to 7.0 times, preferably about 5.0 to 6.5 times.

Each of the polarizers 200 and 300 according to the present invention may include a polarizer protective film on at least one surface of the polarizer.

As the usable protective film, a film superior in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like can be used. Specific examples include polyester resins such as polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate and polybutylene terephthalate; Cellulose-based resins such as diacetylcellulose and triacetylcellulose; Polycarbonate resin; Acrylic resins such as polymethyl (meth) acrylate and polyethyl (meth) acrylate; Styrene resins such as polystyrene and acrylonitrile-styrene copolymer; Polyolefin resins such as polyethylene, polypropylene, cyclo- or norbornene-structured polyolefins, ethylene-propylene copolymers; Vinyl chloride resin; Amide resins such as nylon and aromatic polyamide; Imide resin; Polyether sulfone type resin; Sulfone based resin; Polyether ether ketone resin; A sulfided polyphenylene resin; Vinyl alcohol-based resin; Vinylidene chloride resins; Vinyl butyral resin; Allylate series resin; Polyoxymethylene type resin; Epoxy resin, and the like, and a film composed of the blend of the thermoplastic resin may also be used. Further, a film made of a thermosetting resin such as (meth) acrylic, urethane, acrylic urethane, epoxy, or silicone or a film made of an ultraviolet curable resin may be used.

The content of the thermoplastic resin in the polarizer protective film is preferably 50 to 100% by weight, preferably 50 to 99% by weight, more preferably 60 to 98% by weight, and most preferably 70 to 97% by weight. When the content is less than 50% by weight, the inherent high transparency of the thermoplastic resin may not be sufficiently exhibited.

Such a transparent protective film may contain one or more suitable additives. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a release agent, a coloring inhibitor, a flame retardant, a nucleating agent, an antistatic agent, a pigment and a colorant.

Further, if necessary, the protective film may be surface-treated. Examples of the surface treatment include a chemical treatment such as an alkaline treatment including a dry treatment such as a plasma treatment, a corona treatment, a primer treatment, and a saponification treatment.

Liquid crystal cell

The structure of the liquid crystal cell 10 used in this field is not particularly limited and can be used. For example, the liquid crystal cell includes a pair of liquid crystal cell substrates, a spacer interposed between the liquid crystal cell substrates, a liquid crystal layer formed between the pair of liquid crystal cell substrates, into which liquid crystal material is injected, And an electrode element such as a TFT substrate for driving provided on the inner surface of the other liquid crystal cell substrate.

The liquid crystal material to be injected into the liquid crystal layer is not particularly limited, and an appropriate one may be selected according to the liquid crystal mode. As the liquid crystal mode, for example, a normally black mode such as VA (Vertical Alignment) mode which is a vertical alignment liquid crystal mode or a horizontal alignment liquid crystal mode including an IPS (In-Plane Switching) or FFS do. Among them, the liquid crystal cell of the VA mode is preferable because a very high contrast ratio can be realized.

Polarized rotation layer

The polarization rotation layer 400 has a function of rotating the linearly polarized light passing through the lower plate polarizer 300 by about 90 ° in the upper plate polarizer 200 and the lower plate polarizer 300 in which absorption axes are arranged in parallel. Therefore, even when the absorption axes of the polarizing plates are arranged in parallel, it is possible to realize the normally black mode (the black mode when the liquid crystal is OFF). In the present invention, about 90 deg. Means substantially 90 deg., For example, from 85 deg. To 95 deg..

In addition, the polarization rotation layer 400 according to the present invention has a wavelength dispersion characteristic of inverse dispersion. When the polarization rotation layer 400 is inversely dispersed, the front contrast ratio is remarkably improved, and excellent visual characteristics can be realized.

Preferably, the polarization rotation layer 400 may have a reverse dispersion of Ro (450) / Ro (550) = 0.78 to 0.86 and Ro (650) / Ro (550) = 1.14 to 1.22. If it has the inverse dispersibility in the above range, it can have a remarkably high front contrast ratio.

Preferably, the polarization rotation layer 400 may be a half-wave plate (half-wave plate) having the above-mentioned reverse dispersion. The polarized-light rotating layer 400 may be a half-layer half-wave plate or a two-layer half-wave plate, provided that it has the above-mentioned reverse scattering property. In terms of improvement of the front contrast ratio, it is preferable to use a half-wave plate of two layers. In the case of a two-layer half-wave plate, the individual half-wave plate may not be reverse-scattering only if the two-layer half-wave plate has the above-described reverse scattering property as a whole. For example, the individual half wave plates may be inverse dispersive, constant dispersive, or flat dispersive (Ro (450) / Ro (550) = 1.0 and Ro (650) / Ro (550) = 1.0) By combining these, the polarization rotation layer 400 can be formed of a half-wave plate of two layers. It is preferable to use half wave plates of Ro (450) / Ro (550) = 1 to 1.1 and Ro (650) / Ro (550) = 0.9 to 1 in the case where the individual half wave plates are positively dispersed Do. In order to maximize the improvement effect of the front contrast ratio, it is preferable that the individual half wave plates are inversely dispersible or flatly dispersed.

As a more preferable example of the polarization rotation layer 400, a half-wave plate (half-wave plate) of two layers is formed, and an optical axis of each half- 40 ° and 60 ° to 80 °, preferably 18 ° to 28 ° and 63 ° to 73 °, more preferably 21.5 ° to 24.5 ° and 66.5 ° to 69.5 °. The effect of improving the front contrast ratio is excellent in the above range.

The front contrast ratio can be most remarkably improved when the polarization rotation layer 400 has the above-described structure and optical characteristics.

The half-wave plate can be manufactured from materials known in the art, and is not particularly limited. For example, there may be mentioned polyolefin (polyethylene, polypropylene, polynorbornene, etc.), amorphous polyolefin, polyimide, polyamideimide, polyamide, polyetherimide, polyetheretherketone, polyetherketone, Polyether sulfone, polysulfone, polyphenylene sulfide, polyphenylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyacetal, polycarbonate, polyarylate, polymethyl methacrylate, polymethacrylate Acrylate, vinyl chloride-based resin, vinylidene chloride-based resin, and the like may be used as the binder resin, such as acrylate, acrylate, polyacrylate, polystyrene, cellulose polymer (triacetyl cellulose and the like), PVA, epoxy resin, phenol resin, norbornene resin, May be used alone or as a mixture of two or more thereof. Preferably, Renen resin can be used.

The half-wave plate can be obtained by forming these resin compositions and performing uniaxial or biaxial orientation. An orientation film in which a liquid crystalline polymer or a liquid crystalline monomer is oriented as a half wave plate may also be used

The polarization rotation layer 400 can be disposed without any particular limitation as long as the light transmitted through the lower plate polarizer 300 is allowed to pass through the polarization rotation layer 400 before it is incident on the upper plate polarizer 200. [

For example, as shown in FIG. 2, the upper plate polarizer 200 or the lower plate polarizer 300 may be bonded to one surface of the liquid crystal cell 10 side. FIG. 2 shows an example in which the lower plate polarizer 300 is bonded to one surface of the liquid crystal cell 10 side. The polarizers 200 and 300 may be formed of a polarizer and a protective film bonded to both surfaces of the polarizer. In this case, the polarizers 200 and 300 may be bonded to one surface of the polarizer protective film.

Alternatively, the polarization rotating layer 400 may be formed in place of the protective film on the liquid crystal cell 10 side of the polarizing plates 200 and 300. That is, the polarization rotation layer 400 may be bonded to one surface of the polarizer of the upper plate polarizer 200 or the lower plate polarizer 300, which is the liquid crystal cell 10 side. In this case, since the polarization rotation layer 400 is formed at the position of the protective film, the protective film is not used, and a thin film structure can be realized.

The optical compensation layer (negative B- Plate And negative C- Plate )

In the present invention, the optical compensation layer can be applied without any particular limitation, as long as the optical compensation film does not deviate from the scope of the present invention.

In the present invention, the refractive index ratio (Nz) is defined within the range of the following expression (1), but may be defined by the following expression (5) as long as the expression (1) is satisfied.

Where nx and ny are plane refractive indexes of the film and x is a vibration direction in which the plane refractive index becomes the maximum, the refractive index due to light oscillating in this direction is nx, nx and ny are perpendicular to each other, ny, and nz represents a refractive index perpendicular to the plane defined by nx and ny (film thickness direction). The directional relationships of nx, ny and nz are schematically shown in Fig.

In Equation (5), R _th is a thickness retardation value indicating a difference in refractive index in the thickness direction with respect to an in-plane averaged refractive index, and R _o is a thickness direction retardation value Is defined as a front retardation value which is a substantial retardation when passed.

Where nx and ny are plane refractive indexes of the film and x is a vibration direction in which the plane refractive index becomes the maximum, the refractive index due to light oscillating in this direction is nx, nx and ny are perpendicular to each other, ny, nz represents the refractive index perpendicular to the plane defined by nx and ny (thickness direction of the film), and d represents the thickness of the film.

Where nx and ny are plane refractive indexes of the film and x is a vibration direction in which the plane refractive index becomes the maximum, the refractive index due to light oscillating in this direction is nx, nx and ny are perpendicular to each other, ny, and d represents the thickness of the film.

In general, the types of optical compensation layers are as follows: 1) when light travels in a specific direction, the refractive indexes of all the vibration directions on the traveling direction are all the same, and the light traveling in the traveling direction A-Plate when the optical axis in the in-plane direction is present; 2) C-Plate when the optical axis exists in the vertical direction of the plane; And 3) when there are two optical axes, it is called B-plate. More specifically, it is as follows.

(1) Nz = -∞: Positive C-plate (POSITIVE C PLATE), nz> nx = ny

(2) Nz <0: Positive B-plate (POSITIVE B PLATE), nz> nx> ny

(3) Nz = 0: Negative A-plate (NEGATIVE A PLATE), nx = nz > ny

(4) 0 < Nz < 1: Z-axis oriented film, nx> nz> ny

(5) Nz = 1: Positive A-plate (POSITIVE A PLATE), nx> ny = nz

(6) 1 <Nz: Negative B-plate (NEGATIVE B PLATE), nx> ny> nz

(7) Nz = ∞: Negative C-plate (NEGATIVE C PLATE), nx = ny> nz

However, the above definition is theoretical and it is practically very difficult to make A-Plate, B-Plate and C-Plate perfectly conforming to the above definition. Accordingly, the refractive index ratio, the frontal retardation, and the like are usually set within a predetermined range within a range that does not largely deviate from the above definition, if necessary.

And serves as an optical compensation layer for improving the slope contrast ratio of the negative B-plate 500 and the negative C-plate 600 according to an embodiment of the present invention. The polarizing plate 200 is disposed between the upper polarizer 200 and the lower polarizer 300 .

The value of Equation (1) of the negative B-plate 500 of the present invention is satisfied.

[Equation 1]

(Wherein Ro of the negative B-plate is 50 to 150 nm).

The above formula (1) is a parameter that derives an appropriate range of the refractive index ratio Nz. When the value is satisfied, a remarkably high slope contrast ratio can be realized, and when the refractive index ratio Nz is within a lower limit range , Or when it exceeds the upper limit range, the slope contrast ratio is remarkably lowered, and it is difficult to ensure visibility.

The negative C-plate 500 of the present invention satisfies the value of Equation (2).

&Quot; (2) "

(2) is a parameter derived from an appropriate range of the retardation in the thickness direction (Rth). When the value is satisfied, a remarkably high slope contrast ratio can be realized, and the thickness direction retardation (Rth) When the ratio is less than the lower limit range or exceeds the upper limit range, the slope contrast ratio is remarkably lowered and visibility is difficult to secure.

The refractive index ratio Nz of the negative C-plate 600 according to the present invention has a value of infinity according to the above description, but substantially satisfies 20 or more.

In another preferred embodiment of the present invention, when the negative C-plate 600 is formed of a Discotic liquid crystal polymer, the negative C-plate 600 may satisfy the following equation (3).

&Quot; (3) "

When the value of Equation (3) is satisfied, it can be applied to a Discotic type (positive dispersion) to realize a better slope contrast ratio.

In another preferred embodiment of the present invention, when the negative C-plate 600 is formed of a COP polymer, it may satisfy the following equation (4).

&Quot; (4) "

When the value of Equation (4) is satisfied, it can be applied to the COP type (inverse variance) to realize a better slope contrast ratio.

The positions of the negative B-plate 500 and the negative C-plate 600 can be specifically bonded to either one of the polarizers 200 and 300 or to one side of the liquid crystal cell 10, respectively. Preferably, the upper polarizer or the lower polarizer can be bonded to one side of the liquid crystal cell side of the polarizer. More preferably, a thin film structure can be realized by being directly bonded to a polarizer instead of the protective film of the polarizing plates 200 and 300. [

The negative B-plate 500 and the negative C-plate 600 are bonded to one surface of the polarizer of the upper plate polarizer or the lower plate polarizer, on the side of the liquid crystal cell, and the negative B- If the negative C-plate 600 has a structure that is bonded to the other surface of the polarizer of the upper polarizer or the lower polarizer, the thin C-plate 600 can realize a high contrast ratio and slope contrast ratio.

The liquid crystal panel of the present invention may be a VA mode.

Optionally, the liquid crystal panel of the present invention may further comprise an additional optical function layer. The optical functional layer is not particularly limited as long as it can be used in a liquid crystal panel. Examples of the optical functional layer include an antireflection layer, a hard coating layer, a low refractive index layer, a high refractive index layer, an antifouling layer and an antistatic layer. Layer or more.

Liquid crystal display

The liquid crystal panel of the present invention can be included as one component of a liquid crystal display device. The liquid crystal display device of the present invention is not particularly limited except for the fact that the liquid crystal panel of the present invention described above is used, and other constituent parts and assemblies of the liquid crystal display device can be adopted. Can be prepared by techniques well known in the art.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to be illustrative of the invention and are not intended to limit the scope of the claims. It will be apparent to those skilled in the art that such variations and modifications are within the scope of the appended claims.

Example 1-8 and Comparative Example 1-2

A VA mode liquid crystal panel having the optical characteristics shown in Table 1 below was constructed.

Test Methods

The black luminance of the front and the slope of the liquid crystal panel constructed in accordance with Table 1 is calculated by TechWiz 1D (Sanayisystem), the BLU brightness is 4500 cd / m ² and the front CR Table 2 below shows the correction in such a manner that the measured value and the calculated value of the front contrast ratio when the mutual angle of the polarizer is 85 to 95 degrees are compared with each other using the liquid crystal display apparatus of 5000: For reference, the contrast ratio can be obtained by dividing the white luminance by the black luminance. The front is the normal direction of the liquid crystal panel, and the slope brightness indicates the minimum contrast ratio in all directions in which the difference between the front view angle and the viewing angle (viewing angle) is 60 ° (Φ = 60 °).

According to Table 2, it can be seen that the embodiments having the polarizing rotating layer of the present invention are significantly superior to the comparative examples in the front and slope contrast ratios.

It was confirmed that the slope contrast ratio of the comparative examples deviating from the values of Equation 1 or 2 according to the present invention was remarkably lowered. In the case of Comparative Example 4 having the polarization rotation layer which is not inversely dispersed, the front and slope contrast ratios Was significantly lowered.

10: liquid crystal cell
20, 200: upper plate polarizer 30, 300: lower plate polarizer
400: Polarization rotating layer
500: Negative B-Plate
600: Negative C-Plate

Claims

And a liquid crystal cell disposed between the upper plate polarizer and the lower plate polarizer, wherein the upper plate polarizer and the lower plate polarizer are arranged such that their absorption axes are parallel to each other,
A polarizing rotation layer, a negative B-plate, and a negative C-plate disposed between the upper plate polarizer and the lower plate polarizer,
Wherein the polarizing rotating layer rotates the linearly polarized light by 85 ° to 95 °, and the wavelength dispersion characteristic is inversely dispersed,
The negative B-plate satisfies the following formula (1)
Wherein the negative C-plate satisfies the following formula (2): < EMI ID =
[Equation 1]
0.00041 * Ro ² - 0.12315 * Ro + 10.17798? Nz? 0.00041 * Ro ² - 0.12315 * Ro + 10.37798
&Quot; (2) "
-55.3375 * (Nz value of B-plate) + 434.2867? Rth? -82.5740 * (Nz value of B-plate) + 307.5324
(Wherein Ro of the negative B-plate is 50 to 150 nm).

The liquid crystal panel according to claim 1, wherein the negative C-plate satisfies the following formula (3)
&Quot; (3) "
-82.5740 * (Nz value of B-plate) + 414.2867? Rth? -82.5740 (Nz value of B-plate) + 434.2867.

The liquid crystal panel according to claim 1, wherein the negative C-plate satisfies the following formula (4)
&Quot; (4) "
-55.3375 * (Nz value of B-plate) + 307.5324? Rth? -55.3375 * (Nz value of B-plate) + 327.5324.

The liquid crystal panel according to claim 1, wherein the wavelength dispersion characteristics of the polarization rotation layer are Ro (450) / Ro (550) = 0.78 to 0.86 and Ro (650) / Ro (550) = 1.14 to 1.22.

The liquid crystal panel according to claim 1, wherein the polarization rotation layer is formed as a single layer or a half-wave plate (half-wave plate) of two layers.

The polarizing plate of claim 1, wherein the polarization rotation layer is formed of a half-wave plate (half-wave plate) of two layers, the angle of the optical axis of each half-wave plate with the absorption axis of the polarizing plate is 20 to 40 ° and 60 Deg.] To 80 [deg.].

(450) / Ro (550) = 0.78 to 0.86 and Ro (650) is one of the half wave plates, and the polarizing rotating layer is formed of two half wave plates (half wave plates) / Ro (550) = 1.14 to 1.22.

The liquid crystal panel according to claim 1, wherein the polarizing rotation layer is bonded to one surface of the upper plate polarizer or the lower plate polarizer opposite to the liquid crystal cell.

The liquid crystal panel according to claim 1, wherein the polarization rotation layer is bonded to one surface of the polarizer of the upper plate polarizer or the lower plate polarizer, which is the liquid crystal cell side.

The liquid crystal panel according to claim 1, wherein the negative B-plate is bonded to one surface of the polarizer of the upper plate polarizer or the lower plate polarizer.

The liquid crystal panel according to claim 1, wherein the Nz of the negative C-plate is 20 or more.

The liquid crystal panel according to claim 1, wherein the negative C-plate is bonded to one surface of the polarizer of the upper plate polarizer or the lower plate polarizer.

The liquid crystal panel according to claim 1, wherein the negative B-plate is bonded to one surface of the liquid crystal cell side of the upper plate polarizer or the upper plate polarizer, and the negative C-plate is bonded to one surface of the lower plate polarizer or the lower plate polarizer.

The liquid crystal panel according to claim 1, wherein the liquid crystal cell is a vertically aligned liquid crystal mode.

A liquid crystal display device comprising the liquid crystal panel according to any one of claims 1 to 14.