KR20130074878A - Transflective vertical align liquid crystal display - Google Patents

Abstract

PURPOSE: A transflective vertical align mode liquid crystal display is provided to lower brightness of black status in inclined direction, thereby increasing a contrast ratio. CONSTITUTION: A negative C plate (27,37), a λ/4 phase difference layer (23,33), a phase difference layer which is comprised of a λ/2 biaxial phase difference layer (25,35) and a polarizer (21,31) are laminated in order from liquid crystal cell party. Front phase different value (RO) of the negative C plate is in a range of -0.01-0.01 nm. Thickness direction phase difference value (Rth) of the negative C plate is in a range of 300-231 nm. A refractive index rate (NZ) of the λ/2 biaxial phase difference layer is in a range of 0.75-0.3. RO of the λ/2 biaxial phase difference layer is in a range of 260-250 nm. Rth of the λ/2 biaxial phase difference layer is in a range of -36 - 52 nm.

Description

Transflective Vertical Alignment Mode Liquid Crystal Display {TRANSFLECTIVE VERTICAL ALIGN LIQUID CRYSTAL DISPLAY}

The present invention relates to a transflective vertical alignment mode liquid crystal display device having a high contrast ratio not only in front but also in inclined surfaces.

The transflective liquid crystal display is free to switch to the reflective or transmissive mode according to the user's will.

That is, when the natural light or artificial light is present, the light may be used in the reflective mode, and in the dark, the light may be switched to the transmissive mode using the backlight light inside the liquid crystal display.

As such a transflective liquid crystal display device, it is comprised normally as shown in FIG. In detail, the transflective vertical alignment mode liquid crystal cell 10 has a reflector 13 disposed at a predetermined portion thereof. The upper and lower plates of the liquid crystal cell are disposed in the order of the phase difference layer and the polarizer toward the liquid crystal cell, respectively.

In this case, the retardation layer is used to convert the linearly polarized light into a polarized light by using a λ / 4 retardation layer or a λ / 4 retardation layer and a λ / 2 uniaxial retardation layer.

However, the transflective vertical alignment mode LCD has a high front contrast ratio because it is possible to realize a completely black state from the front side, but it is difficult to secure a wide viewing angle because light leakage occurs in the black state on an inclined surface.

SUMMARY OF THE INVENTION An object of the present invention is to provide a transflective vertical alignment mode liquid crystal display device which can secure a wide viewing angle by improving light leakage on the side surface.

In order to achieve the above object, the present invention is a polarizing plate laminated in the order of a negative C plate, a retardation layer composed of a λ / 4 retardation layer and a λ / 2 biaxial retardation layer and a polarizer from the liquid crystal cell in the upper plate and the lower plate, respectively Wherein the negative C plate is -0.01nm≤front phase difference value (RO) ≤0.01nm, 231nm≤thickness direction phase difference value (Rth) ≤300nm, the lambda / 2 biaxial retardation layer is 0.3≤ refractive index ratio ( NZ)? 0.75, 250 nm? Front phase difference value RO? 260 nm, and -36 nm? Thickness direction phase difference value Rth? 52 nm.

The λ / 2 biaxial retardation layer may have an upper plate of 0.3 ≦ NZ ≦ 0.5 and a lower plate of 0.55 ≦ NZ ≦ 0.75.

The upper and lower plate retardation layers may be formed by laminating a λ / 2 biaxial retardation layer on the λ / 4 retardation layer, respectively.

The upper and lower plate retardation layers may each have a λ / 4 retardation layer laminated on the λ / 2 biaxial retardation layer.

The λ / 4 retardation layer and the λ / 2 biaxial retardation layer may be by liquid crystal coating or by stretching of a film, respectively.

The slow axis of the λ / 4 retardation layer may be substantially 75 ° with respect to the transmission axis of the polarizer, and the slow axis of the λ / 2 biaxial retardation layer may be substantially 15 ° with respect to the transmission axis of the polarizer.

Polarizers of the upper and lower plates may be the absorption axis is perpendicular to each other.

The semi-transmissive vertical alignment mode liquid crystal display device of the present invention has a low luminance in the black state in the inclined direction and thus improves the contrast ratio (white luminance / black luminance), thereby making it clear and ensuring a viewing angle not only on the front side but also on the inclined surface.

1 is a cross-sectional view schematically illustrating a configuration of a conventional general transflective vertical alignment mode liquid crystal display device.
2 is a cross-sectional view schematically showing the configuration of a transflective vertical alignment mode liquid crystal display device according to the present invention;
3A and 3B illustrate a change in polarization state of light emitted in an inclined direction (θ = 70 ° and Φ = 45 °) in Example 1 of the present invention on a Poincare Sphere, and FIG. 3A is a reflection 3b is a transmissive mode,
Figures 4a and 4b is a simulation result of the visibility of the visibility of Example 1 according to the present invention, Figure 4a is a reflective mode and Figure 4b is a transmissive mode,
5A and 5B illustrate changes in polarization state of light emitted in an inclined direction (θ = 70 ° and Φ = 45 °) in Example 2 of the present invention on Poincare Sphere, and FIG. 5A is a reflection 5b is a transmissive mode,
6A and 6B are simulation results of the visibility of the visibility of Example 2 according to the present invention. FIG. 6A is a reflective mode and FIG. 6B is a transmissive mode.
7A and 7B illustrate a change in polarization state of light emitted in an inclined direction (θ = 70 ° and Φ = 45 °) on a Poincare Sphere in Example 3 of the present invention, and FIG. 7A is a reflection 7b is a transmissive mode,
8A and 8B are simulation results of the visibility of the visibility of Example 3 according to the present invention, FIG. 8A is a reflective mode and FIG. 8B is a transmissive mode,
9A and 9B illustrate a change in polarization state of light emitted in an inclined direction (θ = 70 ° and Φ = 45 °) in Example 4 of the present invention on a Poincare Sphere, and FIG. 9A is a reflection. 9b is a transmissive mode,
10A and 10B are simulation results of the visibility of the visibility of Example 4 according to the present invention. FIG. 10A is a reflective mode and FIG. 10B is a transmissive mode.
11A and 11B illustrate a change in polarization state of light emitted in an inclined direction (θ = 70 ° and Φ = 45 °) in Example 5 of the present invention on a Poincare Sphere, and FIG. 11A is a reflection 11b is the transmissive mode,
12A and 12B are simulation results of the visibility omnidirectional transmittance of Example 5 according to the present invention. FIG. 12A is a reflective mode and FIG. 12B is a transmissive mode.
13A and 13B illustrate a change in polarization state of light emitted in an inclined direction (θ = 70 ° and Φ = 45 °) in Example 6 of the present invention on a Poincare Sphere, and FIG. 13A is a reflection 13b is the transmissive mode,
14A and 14B are simulation results of the visibility of omnidirectional transmittance of Example 6 according to the present invention. FIG. 14A is a reflective mode and FIG. 14B is a transmissive mode.
15A and 15B illustrate a change in polarization state of light emitted in an inclined direction (θ = 70 ° and Φ = 45 °) in Example 7 of the present invention on a Poincare Sphere, and FIG. 15A is a reflection 15b is the transmissive mode,
16A and 16B are simulation results of the visibility of omnidirectional transmittance of Example 7 according to the present invention. FIG. 16A is a reflective mode and FIG. 16B is a transmissive mode.
17A and 17B show a change in polarization state of light emitted in an inclined direction (θ = 70 ° and Φ = 45 °) in Comparative Example 1 on Poincare Sphere, and FIG. 17A is a reflection. 17b is the transmissive mode,
18A and 18B are simulation results of the visibility of the visibility of Comparative Example 1 according to the present invention. FIG. 18A is a reflection mode and FIG. 18B is a transmission mode.
19A and 19B show a change in polarization state of light emitted in an inclined direction (θ = 70 ° and Φ = 45 °) in Comparative Example 2 on the Poincare Sphere, and FIG. 19A is a reflection. 19b is a transmissive mode,
20A and 20B are simulation results of the visibility of the visibility of Comparative Example 2 according to the present invention. FIG. 20A is a reflection mode and FIG. 20B is a transmission mode.
21A and 21B show a change in polarization state of light emitted in an inclined direction (θ = 70 ° and Φ = 45 °) in Comparative Example 3 on the Poincare Sphere, and FIG. 21A is a reflection. 21b is the transmissive mode,
22A and 22B are simulation results of the visibility of the visibility of Comparative Example 3 according to the present invention. FIG. 22A is a reflection mode and FIG. 22B is a transmission mode.
23A and 23B show a change in polarization state of light emitted in an inclined direction (θ = 70 ° and Φ = 45 °) in Comparative Example 4 on Poincare Sphere, and FIG. 23A is a reflection 23b is a transmissive mode,
24A and 24B are simulation results of the visibility of the visibility of Comparative Example 4 according to the present invention. FIG. 24A is a reflection mode and FIG. 24B is a transmission mode.
FIG. 25 illustrates a change in polarization state (transmission mode) of light emitted in an inclined direction (θ = 70 ° and Φ = 45 °) in Comparative Example 5 of the present invention on Poincare Sphere.
26 is a simulation result (transmission mode) of the visibility of the visibility of Comparative Example 5 according to the present invention,
27 is a view showing a change in polarization state (transmission mode) of light emitted in an inclined direction (θ = 70 °, Φ = 45 °) in Comparative Example 6 of the present invention on Poincare Sphere.
FIG. 28 is a simulation result (transmission mode) of the visibility of omnidirectional transmittance of Comparative Example 6 according to the present invention. FIG.

The present invention relates to a transflective vertical alignment mode liquid crystal display device having a high contrast ratio (CR, white luminance / black luminance) not only on the front surface but also on the inclined surface.

Hereinafter, the present invention will be described in detail.

The transflective type vertically aligned mode liquid crystal display device of the present invention comprises a polarizing plate laminated in the order of a negative C plate, a retardation layer composed of a λ / 4 retardation layer and a λ / 2 biaxial retardation layer, and a polarizer from the liquid crystal cell on the upper and lower plates. It includes each.

Negative C plates have a relationship of Nx = Ny> Nz and have a refractive index ratio (NZ) of ∞. At this time, Nx and Ny are planar refractive indices, and Nz is a thick direction refractive index.

However, it is practically impossible to make a negative C plate that perfectly conforms to the above theoretical definition. In the general process, in the case of the C plate, the situation is distinguished by setting the range of the front phase difference to an arbitrary value.

The optical characteristics of the negative C plate used in the present invention are -0.01 nm ≤ front phase difference value (RO) ≤ 0.01 nm, preferably the front phase difference value (RO) is 0, and 231 nm ≤ thickness direction phase difference value (Rth) ≤ 300 nm. When the optical characteristic is out of the range, the optical path of the liquid crystal display device to which the optical characteristic is applied may deviate greatly from the circularly polarized state.

The negative C plate usually imparts a phase difference through stretching, specifically triacetyl cellulose (TAC), cycloolefin polymer (COP), cycloolefin copolymer (COC), polyethylene terephthalate (PET), polypropylene (PP) , Polycarbonate (PC), polysulfone (PSF) and polymethyl methacrylate (PMMA) can be prepared from the group consisting of.

The retardation layer is composed of a λ / 4 retardation layer and a λ / 2 biaxial retardation layer, and is commonly referred to as a broadband retardation layer. The broadband retardation layer has a phase delay effect by 1/4 of the entire visible light region. In the liquid crystal display device to which the wideband retardation layer is applied, generation of light leakage and the like can be remarkably improved compared to the lambda / 4 retardation layer, so that image display can be clear.

The slow axis of the λ / 4 retardation layer is arranged to be substantially 75 ° with respect to the transmission axis of the polarizer, and the slow axis of the λ / 2 biaxial retardation layer is substantially 15 ° with respect to the transmission axis of the polarizer. Substantially 75 degrees and substantially 15 degrees mean that it is permissible to about +/- 5 degree about each angle, Specifically, it can be made into the range of 70-80 degree and 10-20 degree.

In addition, light passing through the retardation layer and the polarizer exhibits elliptical polarization (including circular polarization).

In the retardation layer of the present invention, the λ / 2 biaxial retardation layer and the λ / 4 retardation layer may be retardation film layers or retardation liquid crystal layers, respectively, or they may be mixed.

In the present invention, a λ / 2 biaxial retardation layer and a λ / 4 retardation layer may be respectively formed on the polarizer, or a broadband retardation layer (λ / 2 biaxial retardation layer + λ / 4 retardation layer) may be directly formed. .

The λ / 4 retardation layer may be a retardation film layer or a retardation liquid crystal layer.

The lambda / 4 phase difference layer emits a phase delayed by 1/4 with respect to the component oscillating the incident light lambda in the slow axis direction. This delays the phase by 1/4 with respect to any reference wavelength of the incident light λ in the visible light region, and has a phase delay value of 110 to 170 nm based on the incident light having a reference wavelength of 589.3 nm.

The material of the [lambda] / 4 retardation film layer is not particularly limited, but specific intrinsic birefringence values can be produced using positive, negative or mixed materials thereof.

In the present invention, the "material having a positive birefringence value" refers to a material having optically positive uniaxial property when molecules are oriented with a uniaxial order. In addition, in this invention, "a material whose negative birefringence value is negative" means the material which has the characteristic which shows negative uniaxial property optically when a molecule is oriented with uniaxial order. The positive or negative material is preferably a resin.

As the positive resin, specifically, an olefin polymer (eg, polyethylene, polypropylene, norbornene polymer, cycloolefin polymer, etc.), a polyester polymer (eg, polyethylene terephthalate, polybutylene terephthalate, etc.), poly Arylene sulfide-based polymers (e.g., polyphenylene sulfide, etc.), polyvinyl alcohol-based polymers, polycarbonate-based polymers, polyallylate-based polymers, cellulose ester-based polymers (the intrinsic birefringence may be negative), polyether sulfone-based Polymers, polysulfone-based polymers, polyallyl sulfone-based polymers, polyvinyl chloride-based polymers, or poly-membered (binary, ternary, etc.) copolymers thereof. These can use together single 1 type or 2 types or more.

As the negative resin, specifically, polystyrene, polystyrene-based polymer (copolymer of styrene or styrene derivative and other monomer), polyacrylonitrile-based polymer, polymethyl methacrylate-based polymer, cellulose ester-based polymer (the intrinsic birefringence value is Amount), or a multi-membered (two-membered, ternary, etc.) copolymer polymer or the like. These may be used individually by 1 type, but may use 2 or more types together.

The λ / 4 retardation film layer is, for example, produced a film by a solution film forming method or an extrusion molding method, it is diagonally stretched. Gradient stretching is a stretching method in which the direction of slow axis is formed diagonally instead of parallel or perpendicular to the direction of MD (Machine Direction) by varying the moving speed of both ends in the stretching process of the long film.

Moreover, this invention can use the (lambda) / 4 phase (s) difference liquid crystal layer which has the optical anisotropy and the liquid crystal compound which has crosslinking property by light or heat is contained. The liquid crystal compound may include, for example, a reactive liquid crystal compound (RM). Examples of the reactive liquid crystal compound (RM) include those described in Information Display 10, No. 1 (Recent Research Trends of Reactive Liquid Crystal Monomer (RM)).

The reactive liquid crystal compound refers to a monomer molecule having a liquid crystal phase including a mesogen capable of expressing liquid crystal and a terminal group capable of polymerization. By polymerizing the reactive liquid crystal compound, it is possible to obtain a crosslinked polymer network while maintaining the aligned phase of the liquid crystal. When the reactive liquid crystal compound molecules are cooled from the clearing point, a large area domain having a structure that is better aligned at a relatively low viscosity in the liquid crystal phase may be obtained than when the liquid crystal polymer having the same structure is used.

The lambda / 4 phase difference layer thus formed is mechanically and thermally stable because it has a solid thin film form while maintaining the properties such as optical anisotropy and dielectric constant of the liquid crystal.

The reactive liquid crystal compound (RM) may be used as a liquid crystal coating composition by diluting in a solvent in order to secure the efficiency of the coating process and the uniformity of the coating layer. Preferably, it is good to melt | dissolve in the solvent which can melt | dissolve a liquid crystal compound, and to have uniformity.

The lambda / 4 phase difference liquid crystal layer of the present invention can be formed by coating a liquid crystal coating composition containing a reactive liquid crystal compound directly on the polarizer surface.

In addition, the λ / 4 retardation liquid crystal layer may be formed by bonding a transparent protective film to a polarizer with a known adhesive and coating a liquid crystal coating composition containing a reactive liquid crystal compound directly on the transparent protective film.

In addition, a lambda / 2 biaxial retardation layer may be a lambda / 2 biaxial retardation film layer or a lambda / 2 biaxial retardation liquid crystal layer. The λ / 2 biaxial retardation layer delays the phase by one half of a reference wavelength of the incident light λ in the visible light region. In addition, the manufacturing method, material, etc. of a layer are the same as that of the said (lambda) / 4 phase (s) difference layer.

The optical properties of the lambda / 2 biaxial retardation layer used in the present invention is 0.3≤ refractive index ratio (NZ) ≤0.75, 250nm≤front phase difference value (RO) ≤260nm, -36nm≤ thickness direction phase difference value (Rth) ≤ 52 nm range. Preferably, the λ / 2 biaxial retardation layer of the upper plate is 0.3 ≦ NZ ≦ 0.5, and the λ / 2 biaxial retardation layer of the lower plate is 0.55 ≦ NZ ≦ 0.75.

In this case, when NZ, RO, and Rth are out of the above ranges, a problem of leaving the optimized optical path may occur.

The configuration of the transflective vertical alignment mode liquid crystal display device such as a polarizer and a liquid crystal cell of the present invention is generally used in the art and will not be specifically mentioned. At this time, the absorption axes of the upper and lower polarizers are perpendicular to each other.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

Example 1

As shown in FIG. 2, the top plate of the transflective vertical alignment mode liquid crystal cell has a negative C plate having a front phase difference value (RO) of 0 nm and a thickness direction phase difference value (Rth) of 231.3 nm from a liquid crystal cell side, a lambda / 4 phase difference film, The refractive index ratio NZ was 0.36, the front phase difference value RO was 256.8 nm, and the thickness direction phase difference value Rth was -35.97 nm, and it laminated | stacked in the order of (lambda) / 2 biaxial retardation film and polarizer.

In addition, the lower plate has a negative C plate having a front phase difference value (RO) of 0 nm and a thickness direction phase difference value (Rth) of 295.2 nm, a λ / 4 phase difference film, a refractive index ratio (NZ) of 0.7, and a front phase difference value from the liquid crystal cell side. A semi-transmissive vertical alignment mode liquid crystal display device was manufactured by laminating (lambda) / 2 biaxial retardation film and a polarizer having a (RO) of 256.9 nm and a thickness direction phase difference value (Rth) of 51.39 nm.

In this case, the slow axis of the λ / 4 retardation layer is disposed 75 ° with respect to the transmission axis of the adjacent polarizers, and the slow axis of the λ / 2 biaxial retardation layer is 15 ° with respect to the transmission axis of the adjacent polarizers, respectively. The absorption axes of the upper and lower polarizers were arranged to be perpendicular to each other.

3A and 3B show a change in polarization state at a reference time (θ = 70 ° and Φ = 45 °) of the liquid crystal display manufactured above, and FIGS. 4A and 4B show a case where an arm (BLACK) is displayed on a screen. This is the result of simulation of omnidirectional transmittance.

Referring to the transmissive mode of FIG. 3B as an example, polarization state 1 when passing through lower polarizer 21 on Poincare Sphere; polarization state 2 when passing through the λ / 2 biaxial retardation film 23; polarization state 3 when passing through the [lambda] / 4 retardation film 25; Polarization state 4 when passing through negative C plate 27; Polarization state 5 when passing through the liquid crystal cell 10; Polarization state 6 when passing through negative C plate 37; polarization state 7 when passing through the [lambda] / 4 retardation film 35; And a polarization state 8 when passing through the λ / 2 biaxial retardation film 33. It can be confirmed that the polarization state 8 coincides with A, the absorption axis polarization state of the upper polarizer 31.

4A and 4B, the visibility of the omnidirectional transmittance is in the range of 0% to 0.1% of the transmittance on the scale, and when the cancer is displayed, a portion exceeding 0.1% transmittance is indicated in red, and a portion having low transmittance is indicated in blue. In this case, the wider the range of blue in the center, the wider the viewing angle.

Example 2

The same method as in Example 1, except that the upper plate has a λ / 2 biaxial retardation film having a refractive index ratio (NZ) of 0.38, a front phase difference value (RO) of 256.8 nm, and a thickness direction phase difference value (Rth) of -30.91 nm. The lower plate is a semi-transmissive vertical alignment mode liquid crystal using a λ / 2 biaxial retardation film having a refractive index ratio (NZ) of 0.65, a front phase difference value (RO) of 256.9 nm, and a thickness direction phase difference value (Rth) of 38.42 nm. A display device was manufactured.

5A and 5B show a change in polarization state at a reference time (θ = 70 ° and Φ = 45 °) of the liquid crystal display manufactured above, and FIGS. 6A and 6B show a case where an arm (BLACK) is displayed on a screen. This is the result of simulation of omnidirectional transmittance.

Example 3

In the same manner as in Example 1, the upper plate is a λ / 2 biaxial retardation film having a refractive index ratio (NZ) of 0.43, front phase difference value (RO) of 256.8 nm, and thickness direction phase difference value (Rth) of -18.07 nm. The lower plate is a semi-transmissive vertical alignment mode liquid crystal using a λ / 2 biaxial retardation film having a refractive index ratio (NZ) of 0.6, a front phase difference value (RO) of 256.9 nm, and a thickness direction phase difference value (Rth) of 25.58 nm. A display device was manufactured.

7A and 7B show a change in polarization state at a reference time (θ = 70 ° and Φ = 45 °) of the liquid crystal display manufactured above, and FIGS. 8A and 8B show a case where an arm (BLACK) is displayed on a screen. This is the result of simulation of omnidirectional transmittance.

Example 4

In the same manner as in Example 1, the upper plate is a λ / 2 biaxial retardation film having a refractive index ratio (NZ) of 0.48, front phase difference value (RO) of 256.8 nm, and thickness direction phase difference value (Rth) of -5.24 nm. The lower plate is a semi-transmissive vertical alignment mode liquid crystal using a λ / 2 biaxial retardation film having a refractive index ratio (NZ) of 0.55, front phase difference value (RO) of 256.9 nm, and thickness direction phase difference value (Rth) of 12.74 nm. A display device was manufactured.

9A and 9B show a change in polarization state at a reference time (θ = 70 ° and Φ = 45 °) of the liquid crystal display manufactured above, and FIGS. 10A and 10B illustrate a case where an arm (BLACK) is displayed on a screen. This is the result of simulation of omnidirectional transmittance.

Example 5

In the same manner as in Example 1, the upper plate uses a negative C plate having a front phase difference value (RO) of 0 nm and a thickness direction phase difference value (Rth) of 240 nm, and the lower plate has a front phase difference value (RO) of 0 nm and a thickness. A semi-transmissive vertical alignment mode liquid crystal display device was manufactured using a negative C plate having a direction phase difference value (Rth) of 285 nm.

11A and 11B show a change in polarization state at a reference time (θ = 70 ° and Φ = 45 °) of the liquid crystal display manufactured above, and FIGS. 12A and 12B show a case where an arm (BLACK) is displayed on a screen. This is the result of simulation of omnidirectional transmittance.

Example 6

Implemented in the same manner as in Example 1, the upper plate uses a negative C plate having a front phase difference value (RO) of 0 nm and a thickness direction phase difference value (Rth) of 250 nm, and the lower plate has a front phase difference value (RO) of 0 nm and a thickness. A semi-transmissive vertical alignment mode liquid crystal display device was manufactured using a negative C plate having a direction phase difference value Rth of 275 nm.

13A and 13B show a change in polarization state at a reference time (θ = 70 ° and Φ = 45 °) of the liquid crystal display manufactured above, and FIGS. 14A and 14B show a case where an arm (BLACK) is displayed on a screen. This is the result of simulation of omnidirectional transmittance.

Example 7

In the same manner as in Example 1, the upper plate and the lower plate are stacked in the order of a negative C plate, a λ / 2 biaxial retardation film, a λ / 4 retardation film, and a polarizer, respectively, from the liquid crystal cell side, and the transflective vertical alignment mode liquid crystal display. The device was prepared.

15A and 15B show a change in polarization state at a reference time (θ = 70 ° and Φ = 45 °) of the liquid crystal display manufactured above, and FIGS. 16A and 16B show a case where an arm (BLACK) is displayed on a screen. This is the result of simulation of omnidirectional transmittance.

Comparative Example 1

In the same manner as in Example 1, the upper plate and the lower plate were laminated from the liquid crystal cell side in order of λ / 4 retardation film, λ / 2 biaxial retardation film, and polarizer, respectively, to prepare a transflective vertical alignment mode liquid crystal display device. .

17A and 17B show a change in polarization state at a reference time (θ = 70 ° and Φ = 45 °) of the liquid crystal display manufactured above, and FIGS. 18A and 18B show a case where an arm (BLACK) is displayed on a screen. This is the result of simulation of omnidirectional transmittance.

Comparative Example 2

In the same manner as in Example 1, except that the upper plate and the lower plate are respectively negative C plate, λ / 4 retardation film, refractive index ratio (NZ) is 1, front phase difference value (RO) is 256.8 nm, thickness direction phase difference A semi-transmissive vertical alignment mode liquid crystal display device was manufactured by laminating the λ / 2 uniaxial retardation film having a value Rth of 128.5 nm and the polarizer in order.

19A and 19B show a change in polarization state at a reference time (θ = 70 °, Φ = 45 °) of the liquid crystal display manufactured above, and FIGS. 20A and 20B show a case where an arm (BLACK) is displayed on a screen. This is the result of simulation of omnidirectional transmittance.

Comparative Example 3

In the same manner as in Example 1, the upper plate is a λ / 2 biaxial retardation film having a refractive index ratio (NZ) of 0.25, a front phase difference value (RO) of 256.8 nm, and a thickness direction phase difference value (Rth) of -64.29 nm. The lower plate is a semi-transmissive vertical alignment mode liquid crystal using a λ / 2 biaxial retardation film having a refractive index ratio (NZ) of 0.8, a front phase difference value (RO) of 256.9 nm, and a thickness direction phase difference value (Rth) of 76.94 nm. A display device was manufactured.

21A and 21B show a change in polarization state at a reference time (θ = 70 ° and Φ = 45 °) of the liquid crystal display manufactured above, and FIGS. 22A and 22B show a case where an arm (BLACK) is displayed on a screen. This is the result of simulation of omnidirectional transmittance.

Comparative Example 4

In the same manner as in Example 1, the upper plate is a λ / 2 biaxial retardation film having a refractive index ratio (NZ) of 0.2, a front phase difference value (RO) of 256.8 nm, and a thickness direction phase difference value (Rth) of -77.13 nm. The lower plate is a semi-transmissive vertical alignment mode liquid crystal using a λ / 2 biaxial retardation film having a refractive index ratio (NZ) of 0.85, a front phase difference value (RO) of 256.9 nm, and a thickness direction phase difference value (Rth) of 89.78 nm. A display device was manufactured.

23A and 23B show a change in polarization state at a reference time (θ = 70 ° and Φ = 45 °) of the liquid crystal display manufactured above, and FIGS. 24A and 24B illustrate a case where an arm (BLACK) is displayed on a screen. This is the result of simulation of omnidirectional transmittance.

Comparative Example 5

In the same manner as in Example 1, the upper plate is a λ / 2 biaxial retardation film having a refractive index ratio (NZ) of 0.25, a front phase difference value (RO) of 256.8 nm, and a thickness direction phase difference value (Rth) of -64.29 nm. The lower plate is a semi-transmissive vertical alignment mode liquid crystal using a λ / 2 biaxial retardation film having a refractive index ratio (NZ) of 0.7, a front phase difference value (RO) of 256.9 nm, and a thickness direction phase difference value (Rth) of 51.39 nm. A display device was manufactured.

FIG. 25 illustrates a change in polarization state at a reference time (θ = 70 °, Φ45 °) of the liquid crystal display device manufactured above, and FIG. 26 illustrates simulation of visibility omnidirectional transmittance when displaying a black on a screen. It is the result of implementation.

Comparative Example 6

In the same manner as in Example 1, the upper plate is a λ / 2 biaxial retardation film having a refractive index ratio (NZ) of 0.2, a front phase difference value (RO) of 256.8 nm, and a thickness direction phase difference value (Rth) of -77.13 nm. The lower plate is a semi-transmissive vertical alignment mode liquid crystal using a λ / 2 biaxial retardation film having a refractive index ratio (NZ) of 0.7, a front phase difference value (RO) of 256.9 nm, and a thickness direction phase difference value (Rth) of 51.39 nm. A display device was manufactured.

FIG. 27 illustrates a change in polarization state at a reference time (θ = 70 ° and Φ = 45 °) of the liquid crystal display device manufactured above, and FIG. 28 shows the visibility of transmittance in the case of displaying a black on the screen. This is the result of simulation.

10: vertical alignment mode liquid crystal cell
13: reflector
21, 31: polarizer
23, 33: λ / 2 biaxial retardation layer
25, 35: lambda / 4 phase difference layer
27, 37: negative C plate

Claims (7)

In the upper plate and the lower plate, respectively, the liquid crystal cell side comprises a negative C plate, a retardation layer composed of a λ / 4 retardation layer and a λ / 2 biaxial retardation layer, and a polarizer laminated in the order of polarizers, respectively.
The negative C plate has a -0.01 nm ≤ front phase difference value (RO) ≤ 0.01 nm, 231 nm ≤ thickness direction phase difference value (Rth) ≤ 300 nm,
The λ / 2 biaxial retardation layer has a transmissive vertical orientation in which 0.3 ≦ refractive index ratio (NZ) ≦ 0.75, 250 nm ≦ front phase difference value (RO) ≦ 260 nm, and −36 nm ≦ thickness direction phase difference value (Rth) ≦ 52 nm. Mode liquid crystal display device.
The transflective vertical alignment mode liquid crystal display device of claim 1, wherein the λ / 2 biaxial retardation layer has a top plate of 0.3 ≦ NZ ≦ 0.5 and a bottom plate of 0.55 ≦ NZ ≦ 0.75.
The transflective vertical alignment mode liquid crystal display device according to claim 1, wherein the upper and lower plate retardation layers are each laminated with a λ / 2 biaxial retardation layer on a λ / 4 retardation layer.
The transflective vertical alignment mode liquid crystal display device according to claim 1, wherein the upper and lower plate retardation layers are each laminated with a λ / 4 retardation layer on a λ / 2 biaxial retardation layer.
The transflective vertical alignment mode liquid crystal display device according to claim 1, wherein the λ / 4 retardation layer and the λ / 2 biaxial retardation layer are each formed by liquid crystal coating or stretching of a film.
The method of claim 1, wherein the slow axis of the λ / 4 retardation layer is substantially 75 ° with respect to the transmission axis of the polarizer, and the slow axis of the λ / 2 biaxial retardation layer is substantially 15 ° with respect to the transmission axis of the polarizer. Transmissive vertical alignment mode liquid crystal display device.
The transflective vertical alignment mode liquid crystal display device of claim 1, wherein the upper and lower polarizers have absorption axes perpendicular to each other.

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