KR100975805B1 - Liquid crystal display - Google Patents

Abstract

A reflection-transmissive liquid crystal display device having optical conditions for improving display quality is disclosed. The liquid crystal layer has a single cell gap and has a twist angle of 72 ± 10 degrees. The upper λ / 4 retardation film has Δnd1 of 140 ± 10 nm, and the upper λ / 2 retardation film has Δnd2 of 260 ± 10 nm (where Δn is refractive index anisotropy and d is the thickness of the retardation film). The upper [lambda] / 2 retardation film has a slow axis angle of 16 ± 10 degrees with the forward axis centered around the absorption axis angle of the upper polarizing plate, and the upper [lambda] / 4 retardation film has a slow axis angle of 74 ± 10 degrees. Accordingly, while adopting a single cell gap mode, it is possible to improve transmittance and contrast ratio through optimized optical conditions, and to improve display characteristics by symmetrically implementing top, bottom, left and right viewing angles.

Liquid Crystal, Reflective, Transmissive, Optical Conditions, Single Cell Gap, Contrast, Viewing Angle

Description

Liquid crystal display {LIQUID CRYSTAL DISPLAY}

FIG. 1A is a diagram schematically illustrating a general reflection-transmissive liquid crystal display, and FIG. 1B is a diagram for explaining the characteristics of VT (voltage vs. transmittance) and VR (voltage vs. reflectance) of FIG. 1A.

2 is a diagram for describing a general reflection-transmissive liquid crystal display device.

3A to 3C are diagrams for explaining the viewing angle characteristic measurement results of FIG. 2 described above.

4 is a view for explaining a single cell gap reflection-transmissive liquid crystal display according to the present invention.

5 is a view for explaining an optical condition according to the first embodiment of the present invention.

6 is a view for explaining an optical condition according to a second embodiment of the present invention.

7 is a view for explaining an optical condition according to a third embodiment of the present invention.

8A and 8B are graphs of transmission characteristics according to viewing angles corresponding to black characteristics according to a third embodiment of the present invention.

9A and 9B are graphs of transmission characteristics according to viewing angles corresponding to white characteristics according to a third embodiment of the present invention.

10A and 10B are graphs of transmission characteristics according to viewing angles corresponding to contrast ratio characteristics according to a third exemplary embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

100: array substrate 200: color filter substrate

300: liquid crystal layer 400: upper optical film assembly

410: upper lambda / 4 phase difference film 420: upper lambda / 2 phase difference film

430: upper polarizer 500: lower optical film assembly

510: lower lambda / 4 phase difference film 520: lower lambda / 2 phase difference film

530: lower polarizer

The present invention relates to a reflection-transmissive liquid crystal display device, and more particularly, to a reflection-transmission liquid crystal display device having optical conditions for improving display quality.

In general, since reflective type LCDs use natural light incident from the outside, the display becomes dark due to a decrease in the amount of light in a dark place, so that the displayed image cannot be properly viewed.

In addition, since the transmissive type LCD uses artificial light incident from a device such as a backlight, the transmissive type LCD can recognize the displayed image regardless of a bright or dark place, but the power consumption is increased by the amount of the light source. In particular, there is a disadvantage that it is not suitable for a portable display device operated by a battery.

In order to solve these drawbacks, there is a transflective liquid crystal display (Trans-Reflective type LCD) that uses the above-described reflective liquid crystal display and the transmissive liquid crystal display.

FIG. 1A is a diagram schematically illustrating a general reflection-transmissive liquid crystal display, and FIG. 1B is a diagram for explaining the characteristics of VT (voltage vs. transmittance) and VR (voltage vs. reflectance) of FIG. 1A.

Referring to FIG. 1A, a general reflection-transmissive liquid crystal display device 10 includes a lower polarizing plate 11, a lower λ / 2 retardation film 12, and a lower λ / 4 retardation film ( 13), a reflector 14, a liquid crystal layer 15, a color filter 16, an upper λ / 4 retardation film 17, an upper λ / 2 retardation film 18, and an upper polarizing plate 19. The retardation films are used to change linearly polarized light into elliptical polarization or circularly polarized light, to change elliptical polarization or circularly polarized light into linearly polarized light, or to change the polarization direction of linearly polarized light. In particular, the lower and upper λ / 2 retardation films 12 and 18 are used to change the polarization direction of linearly polarized light, and the lower and upper λ / 4 retardation films 13 and 17 change linearly polarized light into circularly polarized light, It is used when changing polarized light into linearly polarized light.

When operating in the transmission mode, the artificial light provided from the backlight assembly (not shown) receives the lower polarizing plate 11, the lower λ / 2 retardation film 12, the lower λ / 4 retardation film 13, the liquid crystal layer 15, and color. An image is displayed by transmitting through the filter 16, the upper lambda / 4 phase difference film 17, the upper lambda / 2 phase difference film 18, and the upper polarizing plate 19.

On the other hand, when operating in the reflection mode, incident through the upper polarizing plate 19, the upper λ / 2 phase difference film 18, the upper λ / 4 phase difference film 17, the color filter 16 and the liquid crystal layer 15 Natural light is reflected using the reflector 14, and the liquid crystal layer 15, the color filter 16, the upper λ / 4 retardation film 17, the upper λ / 2 retardation film 18, and the upper polarizing plate 19. The image is displayed by transmitting through the image.

If the liquid crystal layer 15 is formed of liquid crystal molecules operating in a normally white mode, as shown in FIG. 1B, when the low voltage is applied, the white level is maintained and black when the high voltage is applied. Display the screen by changing to a level. Of course, the VT curve and the VR curve coincide with each other, whether in the transmissive or reflective mode.

However, the above-described reflection-transmissive liquid crystal display device has a 50% reduction in the transmittance in theory in the transmissive mode operation compared with the transmissive liquid crystal display device. The reason for this phenomenon is that all optical conditions must be designed around the reflection area, and thus the transmission area must be designed based on the black characteristics of the transmission.

Accordingly, the technical problem of the present invention is to provide a liquid crystal display device for improving transmittance, contrast ratio, and viewing angle characteristics through optimized optical conditions.

The reflection-transmissive liquid crystal display device according to the first aspect for realizing the object of the present invention is a twist of 72 ± 10 degrees in the liquid crystal display device defining the clockwise direction as the reference angle and the 3 o'clock direction from an observer's point of view. A liquid crystal panel having a liquid crystal layer having an angle; An upper λ / 4 retardation film disposed on the liquid crystal panel with a Δnd1 of 140 ± 10 nm on a light wavelength of 550 nm, wherein Δn is refractive index anisotropy and d1 is the thickness of the upper λ / 4 retardation film; An upper λ / 2 retardation film disposed on the upper λ / 4 retardation film having a Δnd2 of 260 ± 10 nm on a light wavelength of 550 nm, where Δn is refractive index anisotropy and d2 is the thickness of the upper λ / 2 retardation film ); And an upper polarizing plate disposed on the upper λ / 2 retardation film, wherein a slow axial angle of the upper λ / 2 retardation film is 16 ± 10 degrees in a forward direction about the absorption axis angle of the upper polarizing plate, and the upper λ It is characterized in that the slow axis angle of the / 4 retardation film is 74 ± 10 degrees.

The reflection-transmissive liquid crystal display device according to the second aspect for realizing the object of the present invention is a twist of 60 ± 10 degrees in a liquid crystal display device defining a clockwise direction at a reference angle of 3 o'clock from an observer's point of view. A liquid crystal panel having a liquid crystal layer having an angle; An upper λ / 4 retardation film disposed on the liquid crystal panel with a Δnd1 of 140 ± 10 nm on a light wavelength of 550 nm, wherein Δn is refractive index anisotropy and d1 is the thickness of the upper λ / 4 retardation film; An upper λ / 2 retardation film disposed on the upper λ / 4 retardation film having a Δnd2 of 260 ± 10 nm on a light wavelength of 550 nm, where Δn is refractive index anisotropy and d2 is the thickness of the upper λ / 2 retardation film ); And an upper polarizing plate disposed on the upper λ / 2 retardation film, wherein a slow axial angle of the upper λ / 2 retardation film is 104 ± 10 degrees in a forward direction about the absorption axis angle of the upper polarizing plate, and the upper λ / 4 The slow axis angle of the retardation film is 169 ± 10 degrees.

According to a third aspect of the present invention, a reflection-transmissive liquid crystal display device has a twist of 60 ± 10 degrees in a liquid crystal display device defining a clockwise direction at a reference angle of 3 o'clock from an observer's point of view. A liquid crystal panel having a liquid crystal layer having an angle; An upper λ / 4 retardation film disposed on the liquid crystal panel with a Δnd1 of 140 ± 10 nm on a light wavelength of 550 nm, wherein Δn is refractive index anisotropy and d1 is the thickness of the upper λ / 4 retardation film; An upper λ / 2 retardation film disposed on the upper λ / 4 retardation film having a Δnd2 of 260 ± 10 nm on a light wavelength of 550 nm, where Δn is refractive index anisotropy and d2 is the thickness of the upper λ / 2 retardation film ); And an upper polarizing plate disposed on the upper λ / 2 retardation film, wherein a slow axial angle of the upper λ / 2 retardation film is 107 ± 10 degrees in a forward direction around the absorption axis angle of the upper polarizing plate, and the upper λ / 4 The slow axis angle of the retardation film is 174 ± 10 degrees.

The reflection-transmissive liquid crystal display device according to the fourth aspect for realizing the object of the present invention is a twist of 60 ± 10 degrees in a liquid crystal display device defining a clockwise direction at a reference angle of 3 o'clock from an observer's point of view. A liquid crystal panel having an angle and a liquid crystal layer having a viewing angle of 10 ° ± 40 degrees; An upper λ / 4 retardation film disposed on the liquid crystal panel with a Δnd1 of 140 ± 10 nm and a slow axis angle of 104 ± 10 degrees based on an optical wavelength of 550 nm, wherein Δn is refractive anisotropy and d1 is the upper λ / 4 retardation film thickness); An upper λ / 2 retardation film disposed on the upper λ / 4 retardation film having a Δnd2 of 260 ± 10 nm and a slow axis angle of 37 ± 10 degrees based on an optical wavelength of 550 nm, wherein Δn is the refractive index anisotropy, and d2 is the Thickness of the upper λ / 2 retardation film); And an upper polarizing plate disposed on the upper λ / 2 retardation film with an absorption axis angle of 110 ± 10 degrees.

According to a fifth aspect of the present invention, a reflection-transmissive liquid crystal display device has a twist of 72 ± 10 degrees in a liquid crystal display device defining a clockwise direction as a reference angle and a three o'clock position from an observer's point of view. A liquid crystal panel having an angle and a liquid crystal layer having a viewing angle of 12 o'clock ± 40 degrees; An upper λ / 4 retardation film disposed on the liquid crystal panel with a Δnd1 of 140 ± 10 nm and a slow axis angle of 44 ± 10 degrees based on an optical wavelength of 550 nm, wherein Δn is refractive index anisotropy and d1 is the upper λ / 4 retardation film thickness); An upper λ / 2 retardation film disposed on the upper λ / 4 retardation film having a Δnd2 of 260 ± 10 nm and a slow axis angle of 166 ± 10 degrees based on an optical wavelength of 550 nm, wherein Δn is the refractive index anisotropy, and d2 is the Thickness of the upper λ / 2 retardation film); And an upper polarizing plate disposed on the upper λ / 2 retardation film with an absorption axis angle of 150 ± 10 degrees.

The reflection-transmissive liquid crystal display device according to the sixth aspect for realizing the object of the present invention described above is 60 ± 10 degrees in a liquid crystal display device defining a clockwise direction at a reference angle of 3 o'clock from an observer's point of view. A liquid crystal panel comprising a liquid crystal layer having a twist angle and a viewing angle of 10 ° ± 40 degrees; An upper λ / 4 retardation film disposed below the liquid crystal panel with a Δnd1 of 140 ± 10 nm and a slow axis angle of 113 ± 10 degrees based on an optical wavelength of 550 nm, wherein Δn is refractive index anisotropy and d1 is the upper λ / 4 retardation film thickness); An upper λ / 2 retardation film disposed on the upper λ / 4 retardation film having a Δnd2 of 260 ± 10 nm and a slow axis angle of 48 ± 10 degrees based on an optical wavelength of 550 nm, wherein Δn is the refractive index anisotropy and d2 is Thickness of the upper λ / 2 retardation film); And an upper polarizing plate disposed on the upper λ / 2 retardation film with an absorption axis angle of 124 ± 10 degrees.

The reflection-transmissive liquid crystal display device according to the seventh aspect for realizing the object of the present invention is a liquid crystal of 72 ± 10 degrees in a liquid crystal display device defining a clockwise direction at a reference angle of 3 o'clock from an observer's point of view. A liquid crystal panel having a liquid crystal layer having a twist angle; A lower λ / 4 retardation film disposed below the liquid crystal panel with a Δnd1 of 145 ± 10 nm based on a wavelength of 550 nm, wherein Δn is refractive index anisotropy and d1 is the thickness of the lower λ / 4 retardation film; A lower λ / 2 retardation film disposed below the lower λ / 4 retardation film, having a Δnd2 of 270 ± 10 nm on a light wavelength of 550 nm, wherein Δn is refractive index anisotropy, and d2 is the lower λ / 2 retardation film thickness); A lower polarizer disposed under the lower λ / 2 retardation film; An upper λ / 4 retardation film disposed on the liquid crystal panel with a slow axis angle of 106 ± 10 degrees in a forward direction with respect to the absorption axis angle of the lower polarizer; And an upper λ / 2 retardation film disposed on the upper λ / 4 retardation film with a slow axial angle of 165 ± 10 degrees in a forward direction about the absorption axis angle of the lower polarizing plate.

The reflection-transmissive liquid crystal display device according to the eighth aspect for realizing the object of the present invention is a twist of 60 ± 10 degrees in the liquid crystal display device which defines the clockwise direction as the reference angle at 3 o'clock from an observer's point of view. A liquid crystal panel having a liquid crystal layer having an angle; A lower λ / 4 retardation film disposed below the liquid crystal panel with a Δnd1 of 140 ± 10 nm based on a wavelength of 550 nm, wherein Δn is refractive anisotropy and d is 1, the thickness of the lower λ / 4 retardation film; A lower λ / 2 retardation film disposed below the lower λ / 4 retardation film, having a Δnd2 of 270 ± 10 nm on a light wavelength of 550 nm, wherein Δn is refractive index anisotropy, and d2 is the lower λ / 2 retardation film thickness); A lower polarizer disposed under the lower λ / 2 retardation film; An upper λ / 4 retardation film disposed on the liquid crystal panel with a slow axial angle of 104 ± 10 degrees in a forward direction about the absorption axis angle of the lower polarizer; And an upper [lambda] / 2 retardation film disposed on the upper [lambda] / 4 retardation film with a slow axis angle of 38 ± 10 degrees in the forward direction about the absorption axis angle of the lower polarizing plate.

The reflection-transmissive liquid crystal display device according to the ninth aspect for realizing the object of the present invention is a twist of 60 ± 10 degrees in the liquid crystal display device which defines the clockwise direction as the reference angle from the 3 o'clock position from the observer's point of view. A liquid crystal panel having a liquid crystal layer having an angle; A lower λ / 4 retardation film disposed below the liquid crystal panel with a Δnd1 of 140 ± 10 nm on a light wavelength of 550 nm, wherein Δn is refractive index anisotropy and d1 is the thickness of the lower λ / 4 retardation film; A lower λ / 2 retardation film disposed below the lower λ / 4 retardation film, having a Δnd2 of 270 ± 10 nm on a light wavelength of 550 nm, wherein Δn is refractive index anisotropy, and d2 is the lower λ / 2 retardation film thickness); And a lower polarizing plate disposed below the lower λ / 2 retardation film, wherein a slow axial angle of the upper λ / 2 retardation film is 11 ± 10 degrees in a forward direction around the absorption axis angle of the lower polarizing plate, and the upper λ / It is characterized in that the slow axis angle of the four retardation film is 69 ± 10 degrees.

A reflection-transmissive liquid crystal display device according to a tenth aspect for realizing the object of the present invention is a twist of 72 ± 10 degrees in a liquid crystal display device defining a clockwise direction at a reference angle of 3 o'clock from an observer's point of view. A liquid crystal panel having an angle and a liquid crystal layer having a viewing angle of 12 o'clock ± 40 degrees; A lower λ / 4 retardation film disposed below the liquid crystal panel with a Δnd1 of 145 ± 10 nm and a slow axis angle of 46 ± 10 degrees based on an optical wavelength of 550 nm, wherein Δn is refractive index anisotropy, and d1 is the lower λ / 4 retardation film thickness); A lower λ / 2 retardation film disposed below the lower λ / 4 retardation film with Δnd2 of 270 ± 10 nm and a slow axis angle of 105 ± 10 degrees on an optical wavelength of 550 nm, where Δn is the refractive index anisotropy, d2 Is the thickness of the lower λ / 2 retardation film); And a lower polarizing plate disposed below the lower λ / 2 retardation film with an absorption axis angle of 120 ± 10 degrees.

The reflection-transmissive liquid crystal display device according to the eleventh aspect for realizing the object of the present invention described above is 60 ± 10 degrees in a liquid crystal display device defining a clockwise direction at a reference angle of 3 o'clock from an observer's point of view. A liquid crystal panel comprising a liquid crystal layer having a twist angle and a viewing angle of 10 ° ± 40 degrees; A lower λ / 4 phase difference film disposed below the liquid crystal panel with a Δnd1 of 140 ± 10 nm and a slow axis angle of 48 ± 10 degrees based on an optical wavelength of 550 nm, wherein Δn is refractive anisotropy and d1 is the lower λ / 4 retardation film thickness); A lower λ / 2 retardation film disposed below the lower λ / 4 retardation film with Δnd2 of 270 ± 10 nm and a slow axis angle of 162 ± 10 degrees on an optical wavelength of 550 nm, where Δn is the refractive index anisotropy, d2 Is the thickness of the lower λ / 2 retardation film); And a lower polarizing plate disposed below the lower λ / 2 retardation film with an absorption axis angle of 146 ± 10 degrees.

The reflection-transmissive liquid crystal display device according to the twelfth aspect for realizing the object of the present invention is a twist of 60 ± 10 degrees in the liquid crystal display device defining the clockwise direction as the reference angle at 3 o'clock from an observer's viewpoint. A liquid crystal panel having an angle and a liquid crystal layer having a viewing angle of 10 ° ± 40 degrees; A lower λ / 4 retardation film disposed below the liquid crystal panel with a Δnd1 of 140 ± 10 nm and a slow axis angle of 49 ± 10 degrees based on an optical wavelength of 550 nm, wherein Δn is refractive anisotropy and d1 is the lower λ / 4 retardation film thickness); A lower λ / 2 retardation film disposed below the lower λ / 4 retardation film with Δnd2 of 270 ± 10 nm and a slow axis angle of 171 ± 10 degrees based on a wavelength of 550 nm, wherein Δn is the refractive index anisotropy, d2 Is the thickness of the lower λ / 2 retardation film); And a lower polarizing plate disposed below the lower λ / 2 retardation film with an absorption axis angle of 160 ± 10 degrees.                     

According to the reflection-transmissive liquid crystal display device, while adopting a single cell gap mode, it is possible to improve transmittance and contrast ratio through optimized optical conditions, and to realize display characteristics by symmetrically implementing top, bottom, left and right viewing angles.

Hereinafter, with reference to the accompanying drawings, it will be described in detail the present invention.

2 is a diagram for describing optical conditions of a general reflection-transmissive liquid crystal display device. In particular, it is a figure for demonstrating the optical conditions of a reflection-transmissive liquid crystal display device. For convenience of explanation, the reference values of the angles to be described below are assumed to be 0 o'clock, clockwise to the forward direction, and the reference light has an optical wavelength of 550 nm from an observer's point of view. In addition, Δn to be described below defines anisotropic refractive index, d defines the thickness of the phase difference film,

Referring to FIG. 2, the liquid crystal layer formed between the array substrate 15T and the color filter substrate 15C has a Δn of 0.078 ZSM5342, a cell gap d1 of 3.0 μm, a twist angle of 72 degrees, and an optical wavelength of 589 nm. Has a viewing angle of degrees. The upper λ / 4 retardation film 17 is disposed on the color filter substrate 15C, has Δnd2 of 140 nm on the basis of the light wavelength of 550 nm, and has a slow axis that is 74 degrees in the forward direction. The slow axis defines an axis that retards the transmission speed of light. The upper [lambda] / 2 retardation film 18 is disposed on the upper [lambda] / 4 retardation film 17, has a [Delta] nd3 of 260 nm on the basis of the light wavelength of 550 nm, and has a slow axis of 16 ± 10 degrees in the forward direction. The upper polarizing plate 19 is disposed on the upper λ / 2 retardation film 18 and has an absorption axis of 0 ± 10 degrees in the forward direction.

On the other hand, the lower lambda / 4 phase difference film 13 is disposed on the rear surface of the array substrate 15T, has a Δnd4 of 145nm on the basis of the optical wavelength of 550nm, and has a slow axis of 16 degrees in the forward direction. The lower [lambda] / 2 retardation film 12 is disposed on the rear surface of the lower [lambda] / 4 retardation film 13, has a slow axis that is 75 degrees in the forward direction with [Delta] nd5 of 270 nm on the basis of the optical wavelength of 550 nm. The lower polarizing plate 11 is disposed on the rear surface of the lower λ / 2 retardation film 12 and has an absorption axis that is 90 degrees in the forward direction.

3A to 3C are diagrams for explaining the viewing angle characteristic measurement results of FIG. 2 described above. In particular, FIGS. 3A to 3C are graphs of transmission characteristics for each viewing angle corresponding to each of black characteristics, white characteristics, and contrast ratio characteristics observed when the liquid crystal panel is viewed while changing the viewing angle from 12 o'clock to 6 o'clock.

As shown in FIG. 3A, when the liquid crystal panel is observed, black characteristics are observed from the front to the 6 o'clock direction, but normal black characteristics are not observed from the front to the 12 o'clock position, and especially in the vicinity of 60 to 80 degrees, 17.5 [ Cd / m 3], it can be seen that the white characteristic is observed rather. On the other hand, as shown in Fig. 3B, when observing the liquid crystal panel, white characteristics are normally observed in the front vicinity (-20 to 20 degrees).

However, as shown in FIG. 3C, not only can the contrast ratio characteristic be shifted from the front to the lower side, but also the upper and lower contrast characteristics are different.

As described above, in the general reflection-transmissive single cell gap liquid crystal display device, the transmittance is low, and the vertical, horizontal, left and right viewing angles and contrast ratio characteristics are asymmetric, thereby degrading display characteristics.

4 is a cross-sectional view illustrating a single cell gap reflection-transmissive liquid crystal display device according to the present invention. In particular, it is a figure for explaining the single cell gap reflection-transmission type liquid crystal display device of the top ITO system.

Referring to FIG. 4, a single cell gap reflection-transmissive liquid crystal display includes an array substrate 100, a color filter substrate 200, a liquid crystal layer 300 formed between the array substrate 100 and the color filter substrate 200. The upper optical film assembly 400 formed on the color filter substrate 200 and the lower optical film assembly 500 formed below the array substrate 100.

The array substrate 100 includes a gate electrode 110 formed on the transparent substrate 105, a gate electrode 110 formed on the transparent substrate 105, a gate insulating layer 112, a semiconductor layer 114, and an ohmic contact layer 116. And a passivation device that exposes a portion of the drain electrode 130 while covering the switching element TFT and the switching element TFT including the source electrode 120 and the drain electrode 130, and covering the switching element TFT. An organic insulating layer 144 is formed on the layer 140 and the passivation layer 140 while being exposed while exposing a part of the drain electrode 130. Here, it is preferable to form a plurality of grooves and protrusions on the surface of the organic insulating layer 144 to increase the reflection efficiency.

In addition, the array substrate 100 includes a pixel electrode 150 connected to the drain electrode 130 through a first contact hole 141 by opening a portion of the region on the organic insulating layer 144, and the switching element TFT. An interlayer insulating film 152 formed to cover the entirety, and a reflecting plate 160 formed on the interlayer insulating film 152, and a region in which the reflecting plate 160 is formed is defined as a reflecting region, and a region in which the reflecting plate 160 is not formed. Is defined as the transmission window 145.

The pixel electrode 150 is a kind of transmission electrode that transmits light, and indium tin oxide (ITO), tin oxide (TO), or indium zinc oxide (IZO) is used. Although not shown, before the pixel electrode 150 is formed, a separate capacitor wiring is formed in an area spaced from the switching element TFT by a predetermined distance to define the capacitor wiring and the pixel electrode as the storage capacitor Cst.

The reflective plate 160 is formed in a region corresponding to the reflective region of the upper region of the interlayer insulating layer 152. In the drawing, although the reflective plate 160 and the pixel electrode 150 are separated by the interlayer insulating film 152 and electrically insulated, the reflective plate 160 and the pixel are removed by removing a portion (reflected region) of the interlayer insulating film 152. The electrode 150 may be connected.

The color filter substrate 200 may include a black matrix layer (not shown) defining pixel areas of R, G, and B on the transparent substrate 205, and a color pixel layer 210 formed in a region defined by the black matrix layer. And a surface protection layer (not shown) applied to protect the black matrix layer and the color pixel layer 210. Of course, the black matrix function may be provided by overlapping adjacent color pixel layers 210 without forming the black matrix layer. In addition, a common electrode layer, which is not shown, may be further formed on the surface protection layer, that is, the surface close to the liquid crystal layer 300.                     

Meanwhile, the liquid crystal layer 300 is formed between the array substrate 100 and the color filter substrate 200, so that the power applied to the pixel electrode 150 of the array substrate 100 and the common electrode layer of the color filter substrate 200 ( Natural light passing through the color filter substrate 200 may be transmitted or artificial light passing through the transmission window 145 may be transmitted in response to a power applied to the power supply.

In addition, the liquid crystal provided in the liquid crystal layer 300 is homogeneous (or horizontal) aligned to design a twist angle of the liquid crystal molecules to 0 degrees.

In order to design the twist angle to 0 degrees, an alignment film (not shown) provided on the array substrate 100 is rubbed in a right direction, which is a first direction from an observer's point of view, and an alignment film (not shown) provided on the color filter substrate 200. ) May be rubbed in a second direction that is opposite to the first direction, that is, in a left direction, or vice versa.

In the above description, a method of applying power between both ends of the liquid crystal layer 300 by forming a pixel electrode 150 on the array substrate 100 and a common electrode layer (not shown) on the color filter substrate 200 has been described. In the case where the common electrode layer is not formed at 200, the same applies to a liquid crystal display device employing the Coplanar Electrode (CE) mode, for example, in the in-plane switching (IPS) mode or the fringe field switching (FFS) mode. can do.

In the above description, the reflection-transmissive liquid crystal display device having a reflection plate and a transmission window in one unit pixel has been described. However, a switching element, a pixel electrode connected to the drain electrode of the switching element, and a pixel electrode are formed on the pixel electrode to reflect the natural light. The present invention can also be applied to a reflective liquid crystal display device having an array substrate having a reflector.                     

In addition, although the top ITO type reflective-transmissive liquid crystal display device in which the pixel electrode is formed on the organic insulating layer in a thick manner has been described, the present invention may also be applied to the bottom ITO type reflective-transmissive liquid crystal display device formed under the organic insulating layer.

Meanwhile, the upper optical film assembly 400 includes an upper λ / 4 retardation film 410, an upper λ / 2 retardation film 420, and an upper polarizer 430 sequentially formed on the color filter substrate 200, and the lower The optical film assembly 500 includes a lower λ / 4 retardation film 510, a lower λ / 2 retardation film 520, and a lower polarizer 530 sequentially formed below the array substrate 100.

Next, preferred embodiments of the liquid crystal display device having the optical film assembly will be described with reference to the accompanying drawings. For convenience of explanation, the reference values of the angles to be described below are assumed to be 0 o'clock, clockwise to the forward direction, and the reference light has an optical wavelength of 550 nm from an observer's point of view. Further, Δn to be described below defines anisotropic refractive index, d defines the thickness of the phase difference film, and the slow axis defines the axis of retarding the transmission speed of light.

5 is a view for explaining an optical condition according to the first embodiment of the present invention.

Referring to FIG. 5, the liquid crystal layer formed between the array substrate 100 and the color filter substrate 200 has a Δn of 0.078 ZSM5342, a cell gap d1 of 3.0 μm, a twist angle of 72 degrees, and 12 at an optical wavelength of 589 nm. Has a viewing angle of degrees. Δn is the refractive index anisotropy.

The upper λ / 4 retardation film 412 is disposed on the color filter substrate 200, has a Δnd2 of 140 ± 10 nm on the basis of the optical wavelength of 550 nm, and has a slow axis of 44 ± 10 degrees in the forward direction. Here, Δn is refractive index anisotropy, and d2 is the thickness of the upper λ / 4 retardation film.

The upper [lambda] / 2 retardation film 422 is disposed on the upper [lambda] / 4 retardation film 412, has a [Delta] nd3 of 260 ± 10 nm on the basis of the optical wavelength of 550 nm, and has a slow axis of 166 ± 10 degrees in the forward direction. Here, Δn is the refractive index anisotropy, and d3 is the thickness of the upper λ / 2 retardation film.

The upper polarizing plate 432 is disposed on the upper λ / 2 retardation film 422 and has an absorption axis of 150 ± 10 degrees in the forward direction.

On the other hand, the lower λ / 4 retardation film 512 is disposed on the rear surface of the array substrate 100, has a Δnd4 of 145 ± 10 nm on the basis of an optical wavelength of 550 nm, and has a slow axis of 46 ± 10 degrees in the forward direction. Here, Δn is refractive index anisotropy, and d4 is the thickness of the lower λ / 4 retardation film.

The lower λ / 2 retardation film 522 is disposed on the rear surface of the lower λ / 4 retardation film 512, has a Δnd5 of 270 ± 10 nm on the basis of the optical wavelength of 550 nm, and has a slow axis of 105 ± 10 degrees in the forward direction. Here, Δn is refractive index anisotropy, and d5 is the thickness of the lower λ / 2 retardation film.

The lower polarizing plate 532 is disposed on the rear surface of the lower λ / 2 retardation film 522 and has an absorption axis of 120 ± 10 degrees in the forward direction.

According to the optical conditions according to the first embodiment of the present invention described above, the transmittance is 0.2373 and the transmit contrast ratio is 911. Compared with the comparative example described with reference to FIG. 2, it can be seen that the transmittance is increased approximately 20%, and the transmit contrast ratio is almost similar.

On the other hand, according to the optical property measurement results according to the first embodiment measured by the applicant, the reflectance of the comparative example and the first embodiment is the same as 8%, the reflection contrast ratio of the comparative example and the first embodiment is 30 In the same manner, the integrating sphere reflectance of the comparative example and the first embodiment is the same as 5%, and the integrating sphere reflection contrast ratio of the comparative example and the first embodiment is the same as 10.

However, while the front luminance of the comparative example is 55 [Cd / m 2], the front luminance of the first embodiment is 69 [Cd / m 2], so it can be confirmed that the improvement is approximately 25%, and the front contrast ratio of the comparative example is 80 In contrast, since the front contrast ratio of the first embodiment is 110, it can be confirmed that the front contrast ratio is improved by about 12%. The upper, lower, left, and right viewing angles of the comparative example are 21, 36, 22, and 38 degrees, respectively, whereas the first Since the upper, lower, left and right viewing angles of the embodiments are 28, 28, 52, and 22 degrees, the viewing angles for all four directions are superior.

6 is a view for explaining an optical condition according to a second embodiment of the present invention.

Referring to FIG. 6, the liquid crystal layer formed between the array substrate 100 and the color filter substrate 200 has a Δn of 0.078 ZSM5342, a cell gap d1 of 3.0 μm, a twist angle of 60 degrees, and a wavelength of 10, based on an optical wavelength of 589 nm. Has a viewing angle of degrees. Δn is the refractive index anisotropy.

The upper λ / 4 retardation film 414 is disposed on the color filter substrate 200, has a Δnd2 of 140 ± 10 nm on the basis of the light wavelength of 550 nm, and has a slow axis of 113 ± 10 degrees in the forward direction. Here, Δn is refractive index anisotropy, and d2 is the thickness of the upper λ / 4 retardation film.

The upper [lambda] / 2 retardation film 424 is disposed on the upper [lambda] / 4 retardation film 414, has a [Delta] nd3 of 260 ± 10 nm on the basis of the optical wavelength of 550 nm, and has a slow axis of 48 ± 10 degrees in the forward direction. Here, Δn is the refractive index anisotropy, and d3 is the thickness of the upper λ / 2 retardation film.

The upper polarizing plate 434 is disposed on the upper λ / 2 retardation film 424 and has an absorption axis of 124 ± 10 degrees in the forward direction.

On the other hand, the lower λ / 4 retardation film 514 is disposed on the rear surface of the array substrate 100, has a Δnd4 of 130 ± 10 nm on the basis of the wavelength of 550 nm, and has a slow axis of 48 ± 10 degrees in the forward direction. Here, Δn is refractive index anisotropy, and d4 is the thickness of the lower λ / 4 retardation film.

The lower [lambda] / 2 retardation film 524 is disposed on the rear surface of the lower [lambda] / 4 retardation film 514, has a Δnd5 of 270 ± 10 nm on the basis of the optical wavelength of 550 nm, and has a slow axis of 162 ± 10 degrees in the forward direction. Here, Δn is refractive index anisotropy, and d5 is the thickness of the lower λ / 2 retardation film.

The lower polarizer 534 is disposed on the rear surface of the lower λ / 2 retardation film 524 and has an absorption axis of 146 ± 10 degrees in the forward direction.

According to the optical conditions according to the second embodiment of the present invention described above, the transmittance is 0.2838 and the transmit contrast ratio is 2247. Compared with the comparative example described with reference to FIG. 2, it can be seen that the transmittance is increased by approximately 250%, and the transmit contrast ratio is almost similar.

On the other hand, according to the optical property measurement results according to the second embodiment measured by the applicant, the reflectance of the comparative example and the second embodiment is the same as 8%, the reflection contrast ratio of the comparative example and the second embodiment is 30 In the same manner, the integrating sphere reflectance of the comparative example and the second embodiment is the same as 5%, and the integrating sphere reflection contrast ratio of the comparative example and the second embodiment is the same as 10.

However, while the front luminance of the comparative example is 55 [Cd / m 2], the front luminance of the second embodiment is 85 [Cd / m 2], so it can be confirmed that the improvement is approximately 54%, and the front contrast ratio of the comparative example is 80 In contrast, since the front contrast ratio of the second embodiment is 150, it can be confirmed that the front contrast ratio is improved by about 180%. The upper, lower, left, and right viewing angles of the comparative example are 21, 36, 22, and 38 degrees, respectively, while the second Since the upper, lower, left and right viewing angles of the embodiments are 44, 42, 36, and 40 degrees, the viewing angles for all four directions are superior.

7 is a view for explaining an optical condition according to a third embodiment of the present invention.

Referring to FIG. 7, the liquid crystal layer formed between the array substrate 100 and the color filter substrate 200 has a Δn of 0.078 ZSM5342, a cell gap d1 of 3.0 μm, a twist angle of 60 degrees, and a wavelength of 1089 based on an optical wavelength of 589 nm. Has a viewing angle of degrees. Δn is the refractive index anisotropy.

The upper λ / 4 retardation film 416 is disposed on the color filter substrate 200, has a Δnd2 of 140 ± 10 nm on the basis of the optical wavelength of 550 nm, and has a slow axis of 104 ± 10 degrees in the forward direction. Here, Δn is refractive index anisotropy, and d2 is the thickness of the upper λ / 4 retardation film.

The upper [lambda] / 2 retardation film 426 is disposed on the upper [lambda] / 4 retardation film 416, has a [Delta] nd3 of 260 ± 10 nm on the basis of the light wavelength of 550 nm, and has a slow axis of 37 ± 10 degrees in the forward direction. Here, Δn is the refractive index anisotropy, and d3 is the thickness of the upper λ / 2 retardation film.

The upper polarizer 436 is disposed on the upper λ / 2 retardation film 426 and has an absorption axis of 110 ± 10 degrees in the forward direction.

On the other hand, the lower λ / 4 retardation film 516 is disposed on the rear surface of the array substrate 100, has a Δnd4 of 130 ± 10 nm on the basis of an optical wavelength of 550 nm, and has a slow axis of 49 ± 10 degrees in the forward direction. Here, Δn is refractive index anisotropy, and d4 is the thickness of the lower λ / 4 retardation film.

The lower λ / 2 retardation film 526 is disposed on the back side of the lower λ / 4 retardation film 516, has a Δnd5 of 270 ± 10 nm on the basis of the optical wavelength of 550 nm, and has a slow axis of 171 ± 10 degrees in the forward direction. Here, Δn is refractive index anisotropy, and d5 is the thickness of the lower λ / 2 retardation film.

The lower polarizer 536 is disposed on the rear surface of the lower λ / 2 retardation film 526 and has an absorption axis of 160 ± 10 degrees in the forward direction.

According to the optical conditions according to the third embodiment of the present invention described above, the transmittance is 0.2658 and the transmit contrast ratio is 4158. Compared with the comparative example described with reference to FIG. 2, it can be seen that the transmittance increases approximately 35%, and the transmit contrast ratio increases approximately 460%.

On the other hand, according to the optical property measurement results according to the first embodiment measured by the applicant, the reflectance of the comparative example and the third embodiment is the same as 8%, the reflection contrast ratio of the comparative example and the third embodiment is 30 In the same manner, the integrating sphere reflectance of the comparative example and the third embodiment is the same as 5%, and the integrating sphere reflection contrast ratio of the comparative example and the third embodiment is the same as 10.

However, while the front luminance of the comparative example is 55 [Cd / m 2], the front luminance of the third embodiment is 77 [Cd / m 2], so it can be confirmed that the improvement is approximately 40%, and the front contrast ratio of the comparative example is 80 In contrast, since the front contrast ratio of the third embodiment is 190, it can be confirmed that the front contrast ratio is improved by about 230%. The upper, lower, left, and right viewing angles of the comparative example are 21, 36, 22, and 38 degrees, respectively, while the third Since the upper, lower, left and right viewing angles of the embodiments are 44, 42, 36, and 40 degrees, the viewing angles for all four directions are superior.

Next, the transmission viewing angle measurement simulation result of the single cell gap liquid crystal display having the optimized optical condition will be described with reference to the accompanying drawings.

FIG. 8A is a graph illustrating transmission characteristics for each viewing angle corresponding to black characteristics according to a third exemplary embodiment of the present invention, and FIG. 8B is a diagram illustrating the graph of FIG. 8A cut in the longitudinal direction (from 6 o'clock to 12 o'clock). It is a graph showing the luminance characteristics for each viewing angle.

As shown in Figs. 8A and 8B, when observing the liquid crystal panel, high luminance characteristics are observed only in the region near 12 o'clock from the center of the center, and near the center of 80 o'clock from the center of the clock at 6 o'clock. It can be seen that the low luminance characteristic is observed in almost the remaining areas. In particular, it can be confirmed that the low luminance characteristic close to the black level is observed at a luminance of 0.5 [Cd / m 3] near the center of the liquid crystal panel.

FIG. 9A is a graph of transmission characteristics for each viewing angle corresponding to a white characteristic according to a third embodiment of the present invention, and FIG. 9B is a diagram illustrating the aforementioned graph of FIG. 9A cut in the vertical direction (from 6 o'clock to 12 o'clock). It is a graph showing the luminance characteristics for each viewing angle.

As shown in FIGS. 9A and 9B, when observing the liquid crystal panel, it can be seen that high luminance characteristics are uniformly observed in all directions from the center to the region near 30 degrees. In particular, it can be seen that the luminance in the vicinity of the center of the liquid crystal panel is 11 [Cd / m 3], and the high luminance characteristic close to the white level is observed.

FIG. 10A is a graph of transmission characteristics for each viewing angle corresponding to a contrast ratio characteristic according to a third embodiment of the present invention, and FIG. 10B is a diagram illustrating the graph of FIG. 10A cut in the vertical direction (from 6 o'clock to 12 o'clock). It is a graph showing the luminance characteristics for each viewing angle.

As shown in FIGS. 10A and 10B, it can be seen that the contrast ratio is concentrated near the center of the liquid crystal panel. In general, considering that the viewing angle of the observer observing the liquid crystal panel is concentrated near the center, it can be confirmed that the optical condition according to the present invention is optimized.

Although described above with reference to the embodiments, those skilled in the art can be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below. I can understand.

As described above, according to the present invention, a reflection-transmissive liquid crystal display device, in particular, a single cell gap reflection-transmissive liquid crystal, in which a contrast ratio distribution is arranged in the vertical, horizontal, and horizontal directions in terms of the viewing angle in addition to improving the transmittance and contrast ratio of the product. The optical conditions of the display device were secured.

In addition, after applying various optical conditions according to the present invention to the liquid crystal panel, the transmittance can be confirmed that the transmittance is improved by about 40 to 50% and the front contrast ratio is increased by about 200%.

In addition, while the existing reflection mode and transmission mode are both left and right asymmetrical structure in terms of viewing angle, the conditions according to the present invention can be confirmed that the right and left symmetrical distribution and a good level in terms of color characteristics.

Claims (12)

In the liquid crystal display device which defines a clockwise direction as a reference angle from the 3 o'clock position from an observer's point of view, A liquid crystal panel comprising a liquid crystal layer having a twist angle of 72 ± 10 degrees; An upper λ / 4 retardation film disposed on the liquid crystal panel with a Δnd1 of 140 ± 10 nm on a light wavelength of 550 nm, wherein Δn is refractive index anisotropy and d1 is the thickness of the upper λ / 4 retardation film; An upper λ / 2 retardation film disposed on the upper λ / 4 retardation film having a Δnd2 of 260 ± 10 nm on a light wavelength of 550 nm, where Δn is refractive index anisotropy and d2 is the thickness of the upper λ / 2 retardation film ); And An upper polarizer disposed on the upper λ / 2 retardation film, The slow axis angle of the upper λ / 2 retardation film is 16 ± 10 degrees and the slow axis angle of the upper λ / 4 retardation film is 74 ± 10 degrees in a forward direction around the absorption axis angle of the upper polarizing plate. Liquid crystal display. In the liquid crystal display device which defines a clockwise direction as a reference angle from the 3 o'clock position from an observer's point of view, A liquid crystal panel comprising a liquid crystal layer having a twist angle of 60 ± 10 degrees; An upper λ / 4 retardation film disposed on the liquid crystal panel with a Δnd1 of 140 ± 10 nm on a light wavelength of 550 nm, wherein Δn is refractive index anisotropy and d1 is the thickness of the upper λ / 4 retardation film; An upper λ / 2 retardation film disposed on the upper λ / 4 retardation film having a Δnd2 of 260 ± 10 nm on a light wavelength of 550 nm, where Δn is refractive index anisotropy and d2 is the thickness of the upper λ / 2 retardation film ); And An upper polarizer disposed on the upper λ / 2 retardation film, The slow axis angle of the upper λ / 2 phase difference film is 104 ± 10 degrees, and the slow axis angle of the upper λ / 4 phase difference film is 169 ± 10 degrees in a forward direction around the absorption axis angle of the upper polarizing plate. Display device. In the liquid crystal display device which defines a clockwise direction as a reference angle from the 3 o'clock position from an observer's point of view, A liquid crystal panel comprising a liquid crystal layer having a twist angle of 60 ± 10 degrees; An upper λ / 4 retardation film disposed on the liquid crystal panel with a Δnd1 of 140 ± 10 nm on a light wavelength of 550 nm, wherein Δn is refractive index anisotropy and d1 is the thickness of the upper λ / 4 retardation film; An upper λ / 2 retardation film disposed on the upper λ / 4 retardation film having a Δnd2 of 260 ± 10 nm on a light wavelength of 550 nm, where Δn is refractive index anisotropy and d2 is the thickness of the upper λ / 2 retardation film ); And An upper polarizer disposed on the upper λ / 2 retardation film, The slow axis angle of the upper λ / 2 retardation film is 107 ± 10 degrees and the slow axis angle of the upper λ / 4 retardation film is 174 ± 10 degrees in a forward direction around the absorption axis angle of the upper polarizing plate. Display device. In the liquid crystal display device which defines a clockwise direction as a reference angle from the 3 o'clock position from an observer's point of view, A liquid crystal panel comprising a liquid crystal layer having a twist angle of 60 ± 10 degrees and a viewing angle of 10 ± 40 degrees; An upper λ / 4 retardation film disposed on the liquid crystal panel with a Δnd1 of 140 ± 10 nm and a slow axis angle of 104 ± 10 degrees based on an optical wavelength of 550 nm, wherein Δn is refractive index anisotropy and d1 is the upper λ / 4 retardation film thickness); An upper λ / 2 retardation film disposed on the upper λ / 4 retardation film having a Δnd2 of 260 ± 10 nm and a slow axis angle of 37 ± 10 degrees based on an optical wavelength of 550 nm, wherein Δn is the refractive index anisotropy, and d2 is the Thickness of the upper λ / 2 retardation film); And And an upper polarizing plate disposed on the upper λ / 2 retardation film with an absorption axis angle of 110 ± 10 degrees. In the liquid crystal display device which defines a clockwise direction as a reference angle from the 3 o'clock position from an observer's point of view, A liquid crystal panel comprising a liquid crystal layer having a twist angle of 72 ± 10 degrees and a viewing angle of 12 ± 40 degrees; An upper λ / 4 retardation film disposed on the liquid crystal panel with a Δnd1 of 140 ± 10 nm and a slow axis angle of 44 ± 10 degrees based on an optical wavelength of 550 nm, wherein Δn is refractive index anisotropy and d1 is the upper λ / 4 retardation film thickness); An upper λ / 2 retardation film disposed on the upper λ / 4 retardation film having a Δnd2 of 260 ± 10 nm and a slow axis angle of 166 ± 10 degrees based on an optical wavelength of 550 nm, wherein Δn is the refractive index anisotropy, and d2 is the Thickness of the upper λ / 2 retardation film); And A liquid crystal display comprising an upper polarizing plate disposed on an upper λ / 2 retardation film with an absorption axis angle of 150 ± 10 degrees. In the liquid crystal display device which defines a clockwise direction as a reference angle from the 3 o'clock position from an observer's point of view, A liquid crystal panel comprising a liquid crystal layer having a twist angle of 60 ± 10 degrees and a viewing angle of 10 ± 40 degrees; An upper λ / 4 retardation film disposed below the liquid crystal panel with a Δnd1 of 140 ± 10 nm and a slow axis angle of 113 ± 10 degrees based on an optical wavelength of 550 nm, wherein Δn is refractive index anisotropy and d1 is the upper λ / 4 retardation film thickness); An upper λ / 2 retardation film disposed on the upper λ / 4 retardation film having a Δnd2 of 260 ± 10 nm and a slow axis angle of 48 ± 10 degrees based on an optical wavelength of 550 nm, wherein Δn is the refractive index anisotropy and d2 is Thickness of the upper λ / 2 retardation film); And And an upper polarizing plate disposed on the upper λ / 2 retardation film with an absorption axis angle of 124 ± 10 degrees. In the liquid crystal display device which defines a clockwise direction as a reference angle from the 3 o'clock position from an observer's point of view, A liquid crystal panel comprising a liquid crystal layer having a liquid crystal twist angle of 72 ± 10 degrees; A lower λ / 4 retardation film disposed below the liquid crystal panel with a Δnd1 of 145 ± 10 nm based on a wavelength of 550 nm, wherein Δn is refractive index anisotropy and d1 is the thickness of the lower λ / 4 retardation film; A lower λ / 2 retardation film disposed below the lower λ / 4 retardation film, having a Δnd2 of 270 ± 10 nm on a light wavelength of 550 nm, wherein Δn is refractive index anisotropy, and d2 is the lower λ / 2 retardation film thickness); A lower polarizer disposed under the lower λ / 2 retardation film; An upper λ / 4 retardation film disposed on the liquid crystal panel with a slow axis angle of 106 ± 10 degrees in a forward direction with respect to the absorption axis angle of the lower polarizer; And And an upper λ / 2 retardation film disposed on the upper λ / 4 retardation film with a slow axis angle of 165 ± 10 degrees in a forward direction about the absorption axis angle of the lower polarizer. In the liquid crystal display device which defines a clockwise direction as a reference angle from the 3 o'clock position from an observer's point of view, A liquid crystal panel comprising a liquid crystal layer having a twist angle of 60 ± 10 degrees; A lower λ / 4 retardation film disposed below the liquid crystal panel with a Δnd1 of 140 ± 10 nm based on a wavelength of 550 nm, wherein Δn is refractive anisotropy and d is 1, the thickness of the lower λ / 4 retardation film; A lower λ / 2 retardation film disposed below the lower λ / 4 retardation film, having a Δnd2 of 270 ± 10 nm on a light wavelength of 550 nm, wherein Δn is refractive index anisotropy, and d2 is the lower λ / 2 retardation film thickness); A lower polarizer disposed under the lower λ / 2 retardation film; An upper λ / 4 retardation film disposed on the liquid crystal panel with a slow axial angle of 104 ± 10 degrees in a forward direction about the absorption axis angle of the lower polarizer; And And an upper [lambda] / 2 retardation film disposed on the upper [lambda] / 4 retardation film with a slow axis angle of 38 ± 10 degrees in a forward direction about the absorption axis angle of the lower polarizing plate. In the liquid crystal display device which defines a clockwise direction as a reference angle from the 3 o'clock position from an observer's point of view, A liquid crystal panel comprising a liquid crystal layer having a twist angle of 60 ± 10 degrees; A lower λ / 4 retardation film disposed below the liquid crystal panel with a Δnd1 of 140 ± 10 nm on a light wavelength of 550 nm, wherein Δn is refractive index anisotropy and d1 is the thickness of the lower λ / 4 retardation film; A lower λ / 2 retardation film disposed below the lower λ / 4 retardation film, having a Δnd2 of 270 ± 10 nm on a light wavelength of 550 nm, wherein Δn is refractive index anisotropy, and d2 is the lower λ / 2 retardation film thickness); And A lower polarizer disposed below the lower λ / 2 retardation film, The slow axis angle of the upper λ / 2 retardation film is 11 ± 10 degrees, and the slow axis angle of the upper λ / 4 retardation film is 69 ± 10 degrees in a forward direction around the absorption axis angle of the lower polarizing plate. Display device. In the liquid crystal display device which defines a clockwise direction as a reference angle from the 3 o'clock position from an observer's point of view, A liquid crystal panel comprising a liquid crystal layer having a twist angle of 72 ± 10 degrees and a viewing angle of 12 ± 40 degrees; A lower λ / 4 retardation film disposed below the liquid crystal panel with a Δnd1 of 145 ± 10 nm and a slow axis angle of 46 ± 10 degrees based on an optical wavelength of 550 nm, wherein Δn is refractive index anisotropy, and d1 is the lower λ / 4 retardation film thickness); A lower λ / 2 retardation film disposed below the lower λ / 4 retardation film with Δnd2 of 270 ± 10 nm and a slow axis angle of 105 ± 10 degrees on an optical wavelength of 550 nm, where Δn is the refractive index anisotropy, d2 Is the thickness of the lower λ / 2 retardation film); And And a lower polarizing plate disposed below the lower λ / 2 retardation film with an absorption axis angle of 120 ± 10 degrees. In the liquid crystal display device which defines a clockwise direction as a reference angle from the 3 o'clock position from an observer's point of view, A liquid crystal panel comprising a liquid crystal layer having a twist angle of 60 ± 10 degrees and a viewing angle of 10 ± 40 degrees; A lower λ / 4 phase difference film disposed below the liquid crystal panel with a Δnd1 of 140 ± 10 nm and a slow axis angle of 48 ± 10 degrees based on an optical wavelength of 550 nm, wherein Δn is refractive anisotropy and d1 is the lower λ / 4 retardation film thickness); A lower λ / 2 retardation film disposed below the lower λ / 4 retardation film with Δnd2 of 270 ± 10 nm and a slow axis angle of 162 ± 10 degrees on an optical wavelength of 550 nm, where Δn is the refractive index anisotropy, d2 Is the thickness of the lower λ / 2 retardation film); And And a lower polarizing plate disposed below the lower λ / 2 retardation film with an absorption axis angle of 146 ± 10 degrees. In the liquid crystal display device which defines a clockwise direction as a reference angle from the 3 o'clock position from an observer's point of view, A liquid crystal panel comprising a liquid crystal layer having a twist angle of 60 ± 10 degrees and a viewing angle of 10 ± 40 degrees; A lower λ / 4 retardation film disposed below the liquid crystal panel with a Δnd1 of 140 ± 10 nm and a slow axis angle of 49 ± 10 degrees based on an optical wavelength of 550 nm, wherein Δn is refractive anisotropy and d1 is the lower λ / 4 retardation film thickness); A lower λ / 2 retardation film disposed below the lower λ / 4 retardation film with Δnd2 of 270 ± 10 nm and a slow axis angle of 171 ± 10 degrees based on a wavelength of 550 nm, wherein Δn is the refractive index anisotropy, d2 Is the thickness of the lower λ / 2 retardation film); And And a lower polarizing plate disposed below the lower λ / 2 retardation film with an absorption axis angle of 160 ± 10 degrees.

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