JP2017198774A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device having good display quality.SOLUTION: The liquid crystal display device includes: first and second polarizing plates arranged in a crossed Nicol state outside first and second substrates; a C-plate having a retardation of 210 nm to 230 nm in a thickness direction and a biaxial film having a retardation of 430 nm to 450 nm in a thickness direction disposed between the second substrate and the second polarizing plate; and a white light source disposed on an opposite side of the second polarizing plate to the second substrate. An alignment orientation of center molecules in a vertically aligned liquid crystal layer is in a direction which forms an angle of 45° with respect to the orientation of an absorption axis of the first and second polarizing plates, and which is rotated clockwise by (90+θ)° from a first direction, where θ is an angle from θto θ, and θand θare positive angles represented by specific expressions and satisfying θ<θ.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a liquid crystal display device.

  The vertical alignment type liquid crystal display device has two light polarizations arranged in a substantially crossed Nicols configuration, with a very low light transmittance of the background display portion (voltage non-application portion) when observed from the normal direction of the substrate (when viewed from the front). A dark state equivalent to that of a plate can be realized. Further, by using a viewing angle compensator having negative biaxial optical anisotropy, a viewing angle characteristic in a dark state can be ideally realized. Thus, it has excellent display performance.

  FIG. 22 is a schematic sectional view showing the vertical alignment type liquid crystal display element 10 mounted on the vertical alignment type liquid crystal display device.

  The vertical alignment type liquid crystal display element 10 is arranged between an upper substrate (common substrate) 11, a lower substrate (segment substrate) 12, and both substrates 11, 12 that are opposed to each other in a substantially parallel manner and spaced apart from each other. The vertical alignment liquid crystal layer 13 is formed.

  The upper substrate 11 and the lower substrate 12 are bonded to each other by a main seal portion 14 arranged in a frame shape in a plan view (when viewed from the Z-axis positive direction (substrate 11, 12 normal direction)). The vertical alignment liquid crystal layer 13 is disposed inside the main seal portion 14.

  The upper substrate 11 is formed on (i) the upper transparent substrate 11a, (ii) the upper transparent electrode (common electrode) 11b formed on the upper transparent substrate 11a, and (iii) on the upper transparent substrate 11a and the upper transparent electrode 11b. And (iv) an upper vertical alignment film 11d formed on the upper insulating film 11c. Similarly, the lower substrate 12 includes (i) a lower transparent substrate 12a, (ii) a lower transparent electrode (segment electrode) 12b formed on the lower transparent substrate 12a, and (iii) on the lower transparent substrate 12a. And a lower insulating film 12c formed on the lower transparent electrode 12b, and (iv) a lower vertical alignment film 12d formed on the lower insulating film 12c.

  The upper transparent substrate 11a and the lower transparent substrate 12a are, for example, glass substrates. The upper transparent electrode 11b and the lower transparent electrode 12b are formed of a transparent conductive material such as ITO (indium tin oxide).

  Both the electrodes 11b and 12b overlap each other in plan view with the vertical alignment liquid crystal layer 13 interposed therebetween, and a display portion (pixel) is defined in the overlapping region. The upper and lower transparent electrodes 11b and 12b are formed in a pattern so as to realize, for example, a segment display unit (pixel) that displays a specific pattern, a number, or the like, or a plurality of dot matrix-like rectangular display units (pixels). Yes.

  The vertical alignment liquid crystal layer 13 includes a liquid crystal material having a negative dielectric anisotropy. Spacers 13 s are dispersedly arranged in the vertical alignment liquid crystal layer 13.

  An end portion of the lower substrate 12 projects outward from the upper substrate 11, and an external extraction terminal portion 15 is defined in the projected region. The external extraction terminal portion 15 is provided with an external extraction electrode 15b. The external extraction electrode 15b is electrically connected to the lower transparent electrode 12b.

  An upper polarizing plate 17 is disposed on the surface of the upper substrate 11 opposite to the vertical alignment liquid crystal layer 13. A viewing angle compensation plate 16 and a lower polarizing plate 18 are arranged in this order on the surface of the lower substrate 12 opposite to the vertical alignment liquid crystal layer 13. The viewing angle compensation plate 16 and the polarizing plates 17 and 18 are fixed to the substrates 11 and 12 with an adhesive. The upper and lower polarizing plates 17 and 18 are arranged, for example, in crossed Nicols. The viewing angle compensation plate 16 has a function of improving the viewing angle characteristics by optically compensating for a phase difference shift of the vertical alignment liquid crystal layer 13 during oblique observation, for example.

  FIG. 23 is a schematic cross-sectional view showing the vertical alignment type liquid crystal display device 20.

  The vertical alignment liquid crystal display device 20 includes a vertical alignment liquid crystal display element 10, a drive circuit 21, a backlight unit 22, and a housing (housing, cover, etc.) 23.

  The drive circuit 21 is electrically connected to, for example, the external extraction electrode 15b of the vertical alignment type liquid crystal display element 10, and drives the liquid crystal display element 10 by applying a voltage between the electrodes 11b and 12b of the vertical alignment type liquid crystal display element 10. To do.

  The backlight unit 22 includes, for example, an LED light source (backlight) that emits white light, a light guide plate, a diffusion plate, a brightness enhancement film, and the like, and is provided below the lower polarizing plate 18 (Z (Axis negative direction side)

  The vertical alignment type liquid crystal display element 10, the drive circuit 21, and the backlight unit 22 are fixed at a predetermined position in the housing 23 and integrated.

  Note that the drive circuit 21 may be disposed outside the housing 23.

  In particular, in the multiplex drive vertical alignment liquid crystal display device 20 in which the drive circuit 21 outputs a multiplex drive waveform, when the number of scanning lines N is large, in order to increase the contrast and the light transmittance during bright display, The steepness in electro-optical characteristics must be increased. Therefore, it is necessary to increase the retardation Δnd of the vertically aligned liquid crystal layer 13 (the product of the refractive index anisotropy (birefringence index) Δn of the liquid crystal material and the thickness d of the liquid crystal layer 13). In order to increase the retardation Δnd, the refractive index anisotropy Δn of the liquid crystal material must be increased. However, when the refractive index anisotropy Δn of the liquid crystal material is large, the wavelength dispersion characteristic of the refractive index of the liquid crystal material tends to change as compared with the case where Δn is small. Further, the viewing angle compensation plate 16 can use a single or a plurality of optical films having negative uniaxial or biaxial optical anisotropy. However, depending on the arrangement mode and the type of the optical film used, the viewing angle characteristics themselves. And, the color tone of the background during oblique observation changes.

  For example, in the range of retardation Δnd ≧ 550 nm of the liquid crystal layer, a combination of an A plate having positive uniaxial optical anisotropy and a C plate having negative uniaxial optical anisotropy, and two having negative biaxial optical anisotropy. A viewing angle compensation method using a combination of a shaft film and a C plate, a combination of a plurality of biaxial films, and the like has been proposed (for example, see Patent Documents 1 to 3).

  These viewing angle compensation methods optically compensate for the phase shift of the vertically aligned liquid crystal layer 13 during oblique observation, for example. However, the compensation is not ideally performed in the entire visible light wavelength range, Realized in wavelength.

  For example, as shown in FIG. 24A and FIG. 24B, each polarizing plate arranged orthogonally to the central molecular orientation of the liquid crystal layer (the orientation of liquid crystal molecules located in the center of the thickness direction of the liquid crystal layer) and arranged in crossed Nicols The background light transmittance is observed when observed from a polar angle of 50 ° (a direction inclined at an angle of 50 ° with respect to the normal direction of the substrate) at an azimuth of 45 ° with respect to the absorption axis azimuth of, for example, 3 o'clock (0 ° azimuth). The viewing angle compensation condition set to be the lowest (hereinafter referred to as the background light transmission when observed from an oblique direction that is orthogonal to the liquid crystal layer central molecular orientation direction and that forms an angle of 45 ° with the absorption axis direction of the crossed Nicol polarizing plate. In the viewing angle compensation condition set so that the rate is the lowest, it is also referred to as “conventional ideal condition”.) Light near the wavelength of 550 nm is completely blocked, but the light omission of light on the short wavelength side is large. Because of the background display state Is observed as blue or purple.

  In order to suppress this, a method is known in which the retardation Δnd of the liquid crystal layer is made relatively smaller than the retardation Rth in the thickness direction of the viewing angle compensation plate (see, for example, Patent Document 4). However, in this method, when the retardation Rth in the thickness direction of the viewing angle compensator is constant, it is necessary to set the retardation Δnd of the liquid crystal layer to be small. There is a tendency for the light transmittance of the to decrease. Further, when the retardation Δnd of the liquid crystal layer is small, there is a tendency that the change in viewing angle characteristics with respect to the variation in Δnd is large.

  For example, light leakage of light on the short wavelength side is suppressed at least in the horizontal direction (3 o'clock to 9 o'clock direction) without making the retardation Δnd value of the liquid crystal layer smaller than that in the conventional ideal condition. There is a need for a liquid crystal display device that reduces the blueness of the display state.

Japanese Patent No. 4894036 Japanese Patent No. 4873553 Japanese Patent No. 4901541 JP 2008-83546 A

  An object of the present invention is to provide a liquid crystal display device with good display quality.

According to an aspect of the present invention, a first substrate including a first electrode, a second substrate including a second electrode, disposed substantially opposite to the first substrate, and between the first and second substrates A vertically aligned liquid crystal layer disposed on the first substrate, a first polarizing plate disposed on a side opposite to the vertically aligned liquid crystal layer of the first substrate, and on a side opposite to the vertically aligned liquid crystal layer of the second substrate, A second polarizing plate disposed in crossed Nicols with the first polarizing plate, a C plate having a thickness direction retardation of 210 nm to 230 nm disposed between the second substrate and the second polarizing plate, and A biaxial film having a thickness direction retardation of 430 nm to 450 nm, and a white light source disposed on the opposite side of the second polarizing plate from the second substrate, and a central molecule of the vertically aligned liquid crystal layer The orientation direction forms an angle of 45 ° with the absorption axis direction of the first and second polarizing plates, and A direction rotated from the first direction (90 + θ) ° only in the clockwise direction, the theta is theta _l or more, the angle of less theta _u, the theta _l, theta _u satisfies θ _{l <θ u} When the positive angle, the retardation of the vertically aligned liquid crystal layer is Δnd, and the in-plane retardation of the biaxial film is Re,
Is provided.

  According to the present invention, a liquid crystal display device with good display quality can be provided.

FIG. 1 is a schematic perspective view showing a first panel configuration. FIG. 2 is a schematic perspective view showing the configuration of the second panel. FIG. 3 is a schematic perspective view showing the configuration of the third panel. 4A and 4B are graphs showing the lower limit value and the upper limit value of the observation azimuth range in which the chromaticity (x, y) is x> 0.31371 and y> 0.318411, respectively. FIG. 5A is a table showing the values of the calculated coefficients a and b, and FIGS. 5B and 5C are graphs showing the calculation results. FIG. 6A is a table showing the values of the calculated coefficients a and b, and FIGS. 6B and 6C are graphs showing the calculation results. FIG. 7A shows the lower limit of the observation azimuth range (when observing in the direction of a polar angle of 60 °) in which the chromaticity (x, y) is x> 0.31371 and y> 0.318411 under each Re and Δnd conditions. a table showing a theta _l and the upper limit value theta _u, Figure 7B, the table of FIG. 7A, a table which excludes a range asterisk or asterisk is attached, FIG. 7C, the liquid crystal display device, a liquid crystal display 10 is a table showing a preferable range of a lower limit value θ _l to an upper limit value θ _u when the element is rotated clockwise by an angle not less than the lower limit value θ _{l and not} more than the upper limit value θ _u . FIG. 8A is a schematic plan view showing a display area of the liquid crystal display device according to the embodiment, FIG. 8B is a schematic view showing an arrangement example of the liquid crystal display device according to the embodiment, and FIG. 8C is according to the embodiment. It is the schematic which shows the liquid crystal layer 13 center molecular orientation azimuth | direction and the polarizing plate 17 and 18 absorption-axis azimuth | direction in a liquid crystal display device. FIG. 9A and FIG. 9B are graphs showing the lower limit value and upper limit value of the observation azimuth range in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal conditions. 10A to 10D are graphs showing calculation results. FIG. 11A shows the lower limit value θ _l and the upper limit value of the observation azimuth range (when observing in the 60 ° polar angle direction) in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal conditions under each Re and Δnd conditions. a table showing a theta _u, FIG. 11B, the table of FIG. 11A, a table which excludes a range asterisk or asterisk is attached, FIG. 11C, the liquid crystal display device, a liquid crystal display device, the lower limit value 6 is a table showing a preferable range of a lower limit value θ _l to an upper limit value θ _u when rotating clockwise by an angle of θ _l or more and an upper limit value θ _u or less. 12A and 12B are graphs showing the lower limit value and the upper limit value of the observation azimuth range in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal conditions. 13A to 13D are graphs showing calculation results. FIG. 14A shows the lower limit value θ _l and the upper limit value of the observation azimuth range (when observing in the polar angle 60 ° direction) in which the chromaticity is larger than the chromaticity during frontal observation under conventional ideal conditions under each Re and Δnd conditions. a table showing a theta _u, Figure 14B, the table of FIG. 14A, a table which excludes a range asterisk or asterisk is attached, FIG. 14C, the liquid crystal display device, a liquid crystal display device, the lower limit value 6 is a table showing a preferable range of a lower limit value θ _l to an upper limit value θ _u when rotating clockwise by an angle of θ _l or more and an upper limit value θ _u or less. FIG. 15A and FIG. 15B are graphs showing the lower limit value and upper limit value of the observation azimuth range in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal conditions. 16A to 16D are graphs showing calculation results. FIG. 17A shows a lower limit value θ _l and an upper limit value of the observation azimuth range (when observing in the direction of a polar angle of 60 °) in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal conditions under each Re and Δnd conditions. a table showing a theta _u, FIG. 17B, the table of FIG. 17A, a table which excludes a range in which an asterisk or rice marked with. 18A and 18B are graphs showing the lower limit value and the upper limit value of the observation azimuth range in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal condition. 19A to 19D are graphs showing calculation results. FIG. 20A shows the lower limit value θ _l and the upper limit value of the observation azimuth range (when observing in the polar angle 60 ° direction) in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal conditions under each Re and Δnd conditions. a table showing a theta _u, FIG. 20B, the table of FIG. 20A, a table which excludes a range asterisk or asterisk is attached, FIG. 20C, the liquid crystal display device, a liquid crystal display device, the lower limit value 6 is a table showing a preferable range of a lower limit value θ _l to an upper limit value θ _u when rotating clockwise by an angle of θ _l or more and an upper limit value θ _u or less. FIG. 21 shows the lower limit value θ _l and the upper limit value of the observation azimuth range (when observing in the 60 ° polar angle direction) in which the chromaticity is larger than the chromaticity during frontal observation under conventional ideal conditions under each Re and Δnd conditions. It is a table _| surface which shows (theta) _u . FIG. 22 is a schematic sectional view showing the vertical alignment type liquid crystal display element 10 mounted on the vertical alignment type liquid crystal display device. FIG. 23 is a schematic cross-sectional view showing the vertical alignment type liquid crystal display device 20. 24A and 24B are schematic views showing the observation direction.

  The inventors of the present application have conducted intensive research on the viewing angle characteristics of the background (when no voltage is applied) in a plurality of panel configurations of a vertically aligned liquid crystal display element.

  1 to 3 are schematic perspective views showing a panel configuration of a monodomain vertical alignment type liquid crystal display element.

  FIG. 1 shows a first panel configuration. The first panel configuration corresponds to, for example, a panel configuration in which the viewing angle compensation plate 16 of the vertical alignment type liquid crystal display element 10 shown in FIG. 22 is formed in order from the lower substrate 12 side by a C plate 16a and a biaxial film 16b. Note that the 3 o'clock, 6 o'clock, 9 o'clock and 12 o'clock directions are defined in the XY plane of FIG.

  In the first panel configuration, the upper polarizing plate 17 includes a polarizing plate polarizing layer 17a and a base film layer 17b. Similarly, the lower polarizing plate 18 includes a polarizing plate polarizing layer 18a and a base film layer 18b.

  The polarizing plate polarizing layers 17a and 18a are formed of, for example, polyvinyl alcohol (PVA) which is obtained by adsorbing a pigment or iodine and drawing the same. For the base film layers 17b and 18b, for example, a film (TAC film) formed of triacetylcellulose (TAC) is used. The in-plane retardation of the TAC film is, for example, about 5 nm, and the retardation in the thickness direction is, for example, about 50 nm.

  At least one of the base film layers 17b and 18b may be formed of a cycloolefin polymer (COP) or an acrylic resin. The base film layer formed of COP or acrylic resin has no in-plane retardation and no retardation in the thickness direction.

  In addition, although the polarizing plates 17 and 18 are comprised, for example by polarizing plate polarizing layers 17a and 18a and two base film layers which pinch | interpose it, in FIGS. 1-3, the base film of the board | substrates 11 and 12 side is shown. Only the layers 17b, 18b are shown.

  In the first panel configuration, the central molecular orientation of the liquid crystal layer 13 is 6 o'clock (270 ° orientation). For example, when a voltage is applied, the central molecule of the liquid crystal layer 13 is inclined in the 6 o'clock direction. The crossed Nicols polarizing plates 17 and 18 are arranged such that the absorption axis direction forms an angle of about 45 ° with respect to the central molecular alignment direction (6 o'clock direction) of the liquid crystal layer 13 when a voltage is applied. For example, the upper polarizing plate 17 (polarizing plate polarizing layer 17a) has an absorption axis orientation of 135 ° -315 °, and the lower polarizing plate 18 (polarizing plate polarizing layer 18a) has an absorption axis orientation of 45 ° -225 °. is there. The base film layers 17b and 18b (TAC film) are arranged such that the in-plane slow axis direction thereof is parallel to the absorption axis direction of the adjacent polarizing layers 17a and 18a. That is, for example, the in-plane slow axis orientation of the base film layer 17b is 135 ° -315 ° orientation, and the in-plane slow axis orientation of the base film layer 18b is 45 ° -225 ° orientation.

  The C plate 16a has an optical anisotropy ideally having an in-plane retardation of 0 and having a retardation in the thickness direction, but is a commercially available product such as a biaxially stretched film made of COP. In some cases, an in-plane retardation of about 7 nm or less may exist. In that case, the C plate 16a is arranged such that its in-plane slow axis direction is parallel to or orthogonal to the absorption axis directions of the adjacent polarizing plates 17 and 18. In the first panel configuration, when there is an in-plane retardation in the C plate 16a, the in-plane slow axis direction is orthogonal to the absorption axis direction (45 ° -225 ° direction) of the adjacent lower polarizing plate 18. Let That is, the in-plane slow axis direction of the C plate 16a is set to 135 ° to 315 °. The C plate 16a may be arranged so that the in-plane slow axis direction is 45 ° to 225 ° (parallel to the absorption axis direction of the adjacent lower polarizing plate 18).

  The biaxial film 16b is disposed so that its in-plane slow axis direction is substantially perpendicular to the absorption axis directions of the polarizing plates 17 and 18 that are close to each other. In the first panel configuration, the biaxial film 16b has an in-plane slow axis direction orthogonal to the absorption axis direction (45 ° -225 ° direction) of the adjacent lower polarizing plate 18, that is, the plane. It arrange | positions so that an inner slow axis azimuth | direction may become a 135 degree-315 degree azimuth | direction.

  In the first panel configuration, the base film layer 18b is disposed between the biaxial film 16b and the adjacent polarizing layer (polarizing layer 18a), but the base film layer 18b is not disposed, and the biaxial film 16b and the polarized light are disposed. The layer 18a may be directly bonded.

  In the first panel configuration, the viewing angle compensation plate 16 is configured by a laminated structure of the C plate 16a and the biaxial film 16b. However, the viewing angle compensation plate 16 may be configured by only the biaxial film 16b.

  In addition, as shown in FIG. 1, when the viewing angle compensation plate 16 is configured by a laminated structure of a C plate 16a and a biaxial film 16b, the biaxial film 16b is disposed at a position close to the adjacent polarizing plate 18. Is preferred.

  FIG. 2 is a schematic perspective view showing the configuration of the second panel. In the first panel configuration, the C plate 16 a and the biaxial film 16 b are disposed between the lower substrate 12 and the lower polarizing plate 18. However, in the second panel configuration, the upper substrate 11 and the upper polarizing plate 17 are arranged. The C plate 16 a is disposed on the lower substrate 12, and the biaxial film 16 b is disposed between the lower substrate 12 and the lower polarizing plate 18. Other points are the same as the first panel configuration. The in-plane slow axis orientation of the C plate 16a and the in-plane slow axis orientation of the biaxial film 16b are both 135 ° -315 ° orientations in the second panel configuration.

  FIG. 3 is a schematic perspective view showing the configuration of the third panel. In the third panel configuration, the biaxial film 16 b is disposed between the upper substrate 11 and the upper polarizing plate 17, and the C plate 16 a is disposed between the lower substrate 12 and the lower polarizing plate 18. In the third panel configuration, the in-plane slow axis orientation of the C plate 16a and the in-plane slow axis orientation of the biaxial film 16b are both 45 ° -225 ° orientation. Other points are the same as the first panel configuration.

  Common to the first to third panel configurations, the thickness direction retardation of the C plate 16a and the thickness direction retardation of the biaxial film 16b do not need to match, but rather show different values. However, the display state at the time of bright display is good when observed from the direction orthogonal to the liquid crystal layer center molecular orientation direction and at an angle of 45 ° with the absorption axis direction of the crossed Nicol polarizing plate. For example, in the first panel configuration, if the observation tilt angle (polar angle) is large, the light transmittance tends to be remarkably high. Therefore, the display quality at the time of oblique observation is particularly important in the lateral direction (3 o'clock to 9 o'clock). When viewed, it is preferable to set both to different values.

  Also, for example, in the second and third panel configurations, when they match, the liquid crystal layer is observed from an orientation perpendicular to the central molecular orientation of the liquid crystal layer and 45 ° with the absorption axis orientation of the crossed Nicol polarizing plate. In this case, coloring is observed in the display state at the time of bright display, and the light transmittance tends to decrease.

  Therefore, for example, in the first to third panel configurations, the thickness direction retardation of the C plate 16a and the thickness direction retardation of the biaxial film 16b are preferably different from each other, 2: 1 or more. It is more preferable to set the ratio to (one is more than twice the other). For example, in the second and third panel configurations, when the thickness direction retardation of the biaxial film 16b is 440 nm, the thickness direction retardation of the C plate 16a is preferably 220 nm or less or 880 nm or more.

  The inventors of the present application performed a simulation using a simulator LCD MASTER 8.7 one-dimensional analysis made by Shintech Co., Ltd., regarding the viewing angle characteristics of the background (when no voltage is applied) in the first to third panel configurations and the like. In the simulation, it was assumed that polarizing plates SHC13U manufactured by Polatechno Co., Ltd. were used as the crossed Nicols polarizing plates 17 and 18, and that the material of the C plate 16a and the biaxial film 16b was COP. Further, the liquid crystal layer 13 was set to have a pretilt angle of 89.85 ° and a liquid crystal material having a refractive index anisotropy Δn of 0.15. Further, it was assumed that a D65 standard light source is disposed below the lower polarizing plate 18. The absorption axis directions of the upper and lower polarizing plates 17 and 18, the central molecular orientation direction of the liquid crystal layer 13, the in-plane slow axis direction of the C plate 16a, the in-plane slow axis direction of the biaxial film 16b, etc. This is as described with reference to FIG.

[First simulation and first embodiment]
First, in the first panel configuration, a first simulation in which the biaxial film 16b has a thickness direction retardation of 440 nm and the C plate 16a has a thickness direction retardation of 220 nm will be described.

  First, the inventors of the present application perpendicularly intersect the liquid crystal layer 13 central molecular orientation (6 o'clock) and form an angle of 45 ° with the absorption axis orientation of the crossed Nicols polarizing plates 17 and 18, for example, the 3 o'clock orientation. A simulation analysis was performed on viewing angle compensation conditions (conventional ideal conditions) in which the background light transmittance was the lowest when observed from a polar angle of 60 °. As a result, the in-plane retardation Re = 45 nm of the biaxial film 16b, the thickness d = 5.8 μm of the liquid crystal layer 13, and the retardation Δnd = 870 nm of the liquid crystal layer 13 were obtained. Moreover, the chromaticity at the time of front observation was (x, y) = (0.31371, 0.318411).

  Next, the inventors of the present application changed the in-plane retardation Re of the biaxial film 16b and the retardation Δnd of the liquid crystal layer 13 in various ways, and the background light transmittance when tilted to a polar angle of 60 ° from the front ( The observation orientation dependency of the background light transmittance observed from the polar angle of 60 ° direction was calculated. The observation azimuth is expressed as an angle formed with respect to the 3 o'clock (0 °) azimuth. When viewed from the upper polarizing plate 17 side (Z-axis positive direction), the observation direction is a positive angle when it is counterclockwise from the 3 o'clock direction, and is a negative angle when it is clockwise from the 3 o'clock direction.

  Further, from the calculation result of the observation light direction dependency of the background light transmittance, the range in which the chromaticity is larger than the chromaticity (x, y) = (0.31371, 0.318411) at the time of frontal observation under the conventional ideal conditions. That is, an observation azimuth range in which chromaticity (x, y) is x> 0.31371 and y> 0.318411 was calculated. An increase in chromaticity corresponds to yellowing.

  4A and 4B are graphs showing the lower limit value and the upper limit value of the observation azimuth range in which the chromaticity (x, y) is x> 0.31371 and y> 0.318411, respectively. The horizontal axis of both graphs represents the in-plane retardation Re of the biaxial film 16b in the unit “nm”. The vertical axis of the graph shown in FIG. 4A represents the lower limit value of the observation azimuth range where the chromaticity (x, y) is x> 0.31371 and y> 0.318411 in the unit “°”. The vertical axis of the graph shown in 4B represents the upper limit value of the observation azimuth range in the unit “°”. In both graphs, the retardation Δnd of the liquid crystal layer 13 is shown as a parameter. For example, a triangular plot shows the relationship between the in-plane retardation Re of the biaxial film 16b when Δnd = 840 nm, the lower limit value and the upper limit value of the observation azimuth range.

  In the observation from the polar angle of 60 ° in the observation azimuth range not less than the lower limit value shown in FIG. 4A and not more than the upper limit value shown in FIG. 4B, the chromaticity of the background becomes larger than the chromaticity during frontal observation under the conventional ideal conditions. . For example, when the retardation Δnd of the liquid crystal layer 13 is 900 nm and the in-plane retardation Re of the biaxial film 16 b is 40 nm, the liquid crystal is viewed from the polar angle 60 ° direction in the range of 3 ° to 18 ° counterclockwise from 3 o'clock. When the display surface of the display element is viewed, a background color tone having a chromaticity larger than the chromaticity at the time of frontal observation under conventional ideal conditions is observed.

4A and 4B, it is considered that there is a linear relationship between the lower limit value and upper limit value of the observation azimuth range and the in-plane phase difference Re in each Δnd condition. Therefore, for the lower limit value of the observation azimuth range (FIG. 4A), the plotted lower limit value θ _l is fitted by the least square method of the linear model θ _l = a × Re + b in each Δnd condition, and in each Δnd condition. The values of the coefficients a and b were calculated.

  FIG. 5A is a table showing the values of the calculated coefficients a and b. Based on this table, FIG. 5B shows a calculation result (Δnd = 840 nm, 855 nm, 870 nm, 885 nm, 900 nm, 915 nm, 930 nm, 945 nm) with Δnd (unit “nm”) on the horizontal axis and coefficient a on the vertical axis. The value of the coefficient a) was plotted. In FIG. 5C, the horizontal axis is Δnd (unit “nm”), the vertical axis is the coefficient b, and the coefficient b when the calculation result (Δnd = 840 nm, 855 nm, 870 nm, 885 nm, 900 nm, 915 nm, 930 nm, 945 nm) is obtained. Value).

The inventor further shows that in each of FIGS. 5B and 5C, the plot is a quadratic function model (a = α × (Δnd) ² + β × (Δnd) + γ in the case of FIG. 5B, and in the case of FIG. 5C. B = α × (Δnd) ² + β × (Δnd) + γ), and found that curve fitting is possible. As a result of calculation using the least square method, in FIG. 5B, α = 4 × 10 ⁻⁵ , β = −0.0718, γ = 35.349, and in FIG. 5C, α = −0.0027, β = The results were 5.2384 and γ = −2574. That is, the lower limit value θ _l of the observation azimuth range (when observing in the polar angle 60 ° direction) where chromaticity (x, y) is x> 0.31371 and y> 0.318411 is the biaxial film 16b. Using the in-plane retardation Re and the retardation Δnd of the liquid crystal layer 13, the following formula (1)
It was found that

The same calculation was performed for the upper limit value θ _u (FIG. 4B) of the observation azimuth range.

In FIG. 4B, for each Δnd condition, the plotted upper limit value θ _u was fitted by the least square method of the linear model θ _u = a × Re + b, and the values of the coefficients a and b in each Δnd condition were calculated.

  FIG. 6A is a table showing the values of the calculated coefficients a and b. Based on this table, FIG. 6B shows the calculation results (Δnd = 840 nm, 855 nm, 870 nm, 885 nm, 900 nm, 930 nm) with the horizontal axis Δnd (unit “nm”) and the vertical axis the coefficient a. Value) was plotted. In FIG. 6C, the horizontal axis is Δnd (unit “nm”), the vertical axis is coefficient b, and the calculation result (value of coefficient b when Δnd = 840 nm, 855 nm, 870 nm, 885 nm, 900 nm, and 930 nm) is shown. Plotted.

The inventor of the present application further shows that in each of FIG. 6B and FIG. 6C, the plot is a quadratic function model (a = α × (Δnd) ² + β × (Δnd) + γ in the case of FIG. 6B, B = α × (Δnd) ² + β × (Δnd) + γ), and found that curve fitting is possible. As a result of calculation using the least square method, in FIG. 6B, α = −3 × 10 ⁻⁵ , β = 0.0429, γ = −16.797, and in FIG. 6C, α = 0.0016, β = -2.4103 and γ = 923.85 were obtained. That is, the upper limit value θ _u of the observation azimuth range (when observing in the polar angle 60 ° direction) where chromaticity (x, y) is x> 0.31371 and y> 0.318411 is the biaxial film 16b. Using the in-plane retardation Re and the retardation Δnd of the liquid crystal layer 13, the following formula (2)
It was found that

Under the observation azimuth range where the lower limit value is θ _l and the upper limit value is θ _u , and the Re and Δnd conditions, a neutral to brown background color tone that does not contain many short wavelength components is observed when the polar angle is 60 °. Is done.

  The inventors of the present application continued to further study.

FIG. 7A shows the lower limit of the observation azimuth range (when observing in the direction of a polar angle of 60 °) in which the chromaticity (x, y) is x> 0.31371 and y> 0.318411 under each Re and Δnd conditions. a again shows table of theta _l and the upper limit value theta _u.

  As described above, the conventional ideal conditions in the panel configuration of the first simulation are the in-plane retardation Re = 45 nm of the biaxial film 16b and the retardation Δnd = 870 nm of the liquid crystal layer 13. Further, as described in “Background Art”, when the retardation Δnd of the liquid crystal layer 13 is reduced, for example, the steepness in the electro-optical characteristics is deteriorated, the light transmittance at the time of bright display is lowered, or the viewing angle with respect to the variation of Δnd. There is a demand that the retardation Δnd of the liquid crystal layer 13 should not be made smaller than the conventional ideal condition because the change in characteristics tends to be large.

In the table of FIG. 7A, an asterisk (*) is added to the range of the lower limit value θ _l to the upper limit value θ _u where the retardation Δnd of the liquid crystal layer 13 is smaller than the conventional ideal condition.

Furthermore, the conventional liquid crystal display device having the Re and Δnd conditions in the range including 0 ° between the lower limit value θ _l and the upper limit value θ _u has a chromaticity when observed from the polar angle of 60 ° in the 3 o'clock direction. The liquid crystal display device is larger than the chromaticity at the time of frontal observation and is described in “Background Technology”, “at least in the horizontal direction (3 o'clock to 9 o'clock direction), the blueness of the background display state is reduced”. It can be said. That is, the range including 0 ° between the lower limit value θ _l and the upper limit value θ _u is considered to be a range including the configuration of the conventional liquid crystal display device.

In the table of FIG. 7A, an asterisk (*) is attached to the observation azimuth range (excluding the range marked with *) including 0 ° between the lower limit value θ _l and the upper limit value θ _u .

  FIG. 7B is a table in which the range marked with an asterisk (*) or an American mark (*) is excluded from the table of FIG. 7A.

It can be seen that both the lower limit value θ _l and the upper limit value θ _u are positive values.

For example, in the panel configuration of the first simulation, the Re and Δnd conditions shown in this table are applied, and the corresponding observation azimuth (observation azimuth not less than the lower limit θ _{l and not} more than the upper limit θ _u ) is viewed from the direction of the polar angle 60 °. When the display surface of the liquid crystal display element is observed, a background color tone having a chromaticity larger than the chromaticity during frontal observation under the conventional ideal condition is observed. Further, Δnd applied has a value equal to or higher than the retardation of the liquid crystal layer under the conventional ideal conditions.

For this reason, in the liquid crystal display device, the liquid crystal display element is rotated in the reverse direction (clockwise direction) by an angle not less than the lower limit value θ _{l and not} more than the upper limit value θ _u , for example. A liquid crystal display device having Δnd equal to or higher than the retardation, and that suppresses light leakage of light on the short wavelength side and reduces the blueness of the background display state at least in the left-right direction (3 o'clock to 9 o'clock direction). It is feasible.

Here, the lower limit value θ _l is a positive value and is represented by the following equation (1).

The upper limit value θ _u is a positive value that satisfies θ _l <θ _u and is represented by the following equation (2).

FIG. 7C shows a preferable lower limit value θ _l to upper limit value when the liquid crystal display element is rotated in the reverse direction (clockwise direction) by an angle not less than the lower limit value θ _{l and not} more than the upper limit value θ _u in the liquid crystal display device, for example. It is a table | surface which shows the range of (theta) _u . This table is created by changing the upper limit value θ _u to 25 ° when the upper limit value θ _u shown in the table of FIG. 7B exceeds 25 °, and the upper limit value θ _{u is set} to 25 °. Are marked with a sharp (#).

For example, when a vertically aligned liquid crystal display element of monodomain alignment is rotated in a range exceeding 25 °, it is assumed that the asymmetry of the light transmittance appears remarkably during the left and right observation of bright display. For this reason, when the value of the upper limit value θ _u exceeds 25 °, the display quality can be improved by setting the upper limit value θ _u to 25 ° (the rotation angle is set to 25 ° or less).

  In the first simulation, in the first panel configuration, the thickness direction retardation of the biaxial film 16b is 440 nm and the thickness direction retardation of the C plate 16a is 220 nm. However, in the second panel configuration and the third panel configuration, It was found that substantially equivalent results were obtained when the thickness direction retardation of the biaxial film 16b was 440 nm and the thickness direction retardation of the C plate 16a was 220 nm.

  Based on the knowledge obtained by the first simulation or the like, for example, the following liquid crystal display device can be used as the liquid crystal display device according to the first embodiment.

  The liquid crystal display device according to the first embodiment has, for example, the configuration shown in FIG. For example, a vertical alignment liquid crystal display element 10, a drive circuit 21 that applies a voltage between the electrodes 11 b and 12 b of the liquid crystal display element 10, and multiplex-drives the liquid crystal display element 10 as an example, and a lower side of the liquid crystal display element 10 A white light source (backlight unit 22) disposed below the polarizing plate 18 is included.

  The vertical alignment type liquid crystal display element 10 is, for example, a monodomain alignment liquid crystal display element, and has a configuration shown in FIG. For example, the upper substrate 11 including the upper transparent electrode 11 b, the lower substrate 12 including the lower transparent electrode 12 b, and disposed substantially opposite to the upper substrate 11, and the vertical alignment disposed between the substrates 11 and 12. And a liquid crystal layer 13.

  An upper polarizing plate 17 is disposed on the surface of the upper substrate 11 opposite to the vertical alignment liquid crystal layer 13. A viewing angle compensation plate 16 and a lower polarizing plate 18 are arranged in this order on the surface of the lower substrate 12 opposite to the vertical alignment liquid crystal layer 13. The upper and lower polarizing plates 17 and 18 are arranged in crossed Nicols. The viewing angle compensation plate 16 has a laminated structure of, for example, a C plate 16a and a biaxial film 16b in order from the lower substrate 12 side. The thickness direction retardation of the C plate 16a is 220 nm, and the thickness direction retardation of the biaxial film 16b is 440 nm.

  Both electrodes 11b and 12b define a display portion (pixel) in a region where they overlap each other in plan view. An area where display is performed using pixels is a display area. The display area (display surface) of the liquid crystal display element 10 is defined on the upper substrate 11 side.

The liquid crystal display device according to the first embodiment is a liquid crystal display in which the liquid crystal display element having the first panel configuration (see FIG. 1) is rotated clockwise by an angle θ not less than the lower limit θ _{l and not} more than the upper limit θ _u , for example. Device. Both the lower limit value θ _l and the upper limit value θ _u are positive angles and satisfy θ _l <θ _u . Further, the lower limit value θ _l and the upper limit value θ _u are expressed by the following formulas (1) and (2). The units of θ, θ _l , and θ _u are all “°”.

  FIG. 8A shows a display area (display surface) of the liquid crystal display device according to the first embodiment. The vertical direction of the display area is 12 o'clock-6 o'clock direction (up direction is 12 o'clock direction, down direction is 6 o'clock direction), horizontal direction is 3 o'clock-9 o'clock direction (right direction is 3 o'clock direction, left direction is 9 o'clock direction).

  As shown in FIG. 8B, the liquid crystal display device according to the first embodiment is disposed, for example, in a console (HVAC display section) between a driver seat 31 and a passenger seat 32 in an automobile.

  FIG. 8C shows the central molecular orientation of the liquid crystal layer 13 and the absorption axes of the polarizing plates 17 and 18 in the liquid crystal display device according to the first embodiment.

  In the liquid crystal display device according to the first embodiment, the central molecular orientation of the liquid crystal layer 13 is a (270-θ) ° azimuth and rotates clockwise from the right direction (3 o'clock) of the display region by (90 + θ) °. Direction. The absorption axis orientation of the crossed Nicols polarizing plates 17 and 18 is an orientation that forms an angle of 45 ° with the central molecular orientation orientation of the liquid crystal layer 13. For example, the absorption axis orientation of the upper polarizing plate 17 is (135−θ) ° − (315 The −θ) ° azimuth and the lower polarizer 18 absorption axis azimuth are (45−θ) ° − (225−θ) ° azimuth.

  The liquid crystal display device according to the first embodiment is a liquid crystal display device having good display quality. For example, light leakage of light on the short wavelength side is suppressed at 60 ° oblique observation at least in the left-right direction (3 o'clock to 9 o'clock direction) with Δnd equal to or higher than the retardation of the liquid crystal layer under conventional ideal conditions, and the background This is a liquid crystal display device in which the blueness of the display state is reduced. For example, a brown background color tone can be realized in the horizontal direction.

  The angle θ is preferably 25 ° or less. By setting θ to 25 ° or less, it is possible to suppress the appearance of asymmetry of the light transmittance in the horizontal direction during bright display.

  In the liquid crystal display device according to the first embodiment, the central molecular orientation direction of the liquid crystal layer 13 is the direction rotated clockwise by (90 + θ) ° from the right direction of the display area, but is not limited to the right direction of the display area. Alternatively, a direction rotated clockwise by (90 + θ) ° from the first direction for reducing the bluishness of the background color tone may be used.

Further, the liquid crystal display element of the first panel configuration (see FIG. 1) (the liquid crystal display element in which the C plate 16a and the biaxial film 16b are disposed between the lower substrate 12 and the lower polarizing plate 18) is set to the lower limit value θ _l. above, not only the liquid crystal display device is rotated in the clockwise direction by an angle of less than theta upper limit theta _u, during a second panel constituting the liquid crystal display device (the upper substrate 11 and the upper polarizing plate 17 (see FIG. 2) A liquid crystal display element in which a C plate 16a is arranged and a biaxial film 16b is arranged between the lower substrate 12 and the lower polarizing plate 18), and a liquid crystal display element (see FIG. 3) in the third panel configuration (see FIG. 3) A liquid crystal display element in which a biaxial film 16b is disposed between the upper polarizing plates 17 and a C plate 16a is disposed between the lower substrate 12 and the lower polarizing plate 18 is, for example, a lower limit value _θl or more and an upper limit value θ. Rotate clockwise by angle θ less than _u A liquid crystal display device can be provided.

  Furthermore, the thickness direction retardation of the biaxial film 16b may be in the range of 440 nm ± 10 nm (430 nm to 450 nm), and the thickness direction retardation of the C plate 16a may be in the range of 220 nm ± 10 nm (210 nm to 230 nm). The same effect as the case where the thickness direction retardation of the biaxial film 16b is 440 nm and the thickness direction retardation of the C plate 16a is 220 nm will be exhibited.

  The inventors of the present application performed the second to sixth simulations similarly to the first simulation.

[Second simulation and second embodiment]
In the first panel configuration, a second simulation in which the thickness direction retardation of the biaxial film 16b is 220 nm and the thickness direction retardation of the C plate 16a is 440 nm will be described.

  First, from a direction orthogonal to the central molecular alignment direction (6 o'clock direction) of the liquid crystal layer 13 and 45 ° with the absorption axis direction of the crossed Nicols polarizing plates 17 and 18, for example, from the polar angle 60 ° direction of the 3 o'clock direction A simulation analysis was performed on the viewing angle compensation condition (conventional ideal condition) in which the background light transmittance was the lowest when observed. As a result, the in-plane retardation Re = 50 nm of the biaxial film 16b and the retardation Δnd = 870 nm of the liquid crystal layer 13 were obtained.

  Next, the in-plane retardation Re of the biaxial film 16b and the retardation Δnd of the liquid crystal layer 13 are variously changed, and the background light transmittance when tilted from the front to the polar angle 60 ° (from the polar angle 60 ° direction) The observation orientation dependency of the observed background light transmittance) was calculated. The observation azimuth is expressed as an angle formed with respect to the 3 o'clock (0 °) azimuth. When viewed from the upper polarizing plate 17 side (Z-axis positive direction), the observation direction is a positive angle when it is counterclockwise from the 3 o'clock direction, and is a negative angle when it is clockwise from the 3 o'clock direction.

  Further, from the calculation result of the dependency of the background light transmittance on the observation direction, an observation direction range in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal condition was calculated.

  FIG. 9A and FIG. 9B are graphs showing the lower limit value and upper limit value of the observation azimuth range in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal conditions. The horizontal axis of both graphs represents the in-plane retardation Re of the biaxial film 16b in the unit “nm”. The vertical axis of the graph shown in FIG. 9A represents the lower limit value of the observation azimuth range in which the chromaticity is larger than the chromaticity at the time of frontal observation under the conventional ideal condition in the unit “°”. The vertical axis represents the upper limit value of the observation azimuth range in the unit “°”. In both graphs, the retardation Δnd of the liquid crystal layer 13 is shown as a parameter. For example, a triangular plot shows the relationship between the in-plane retardation Re of the biaxial film 16b when Δnd = 915 nm and the lower limit value and upper limit value of the observation azimuth range.

  In the observation from the polar angle of 60 ° in the observation azimuth range not less than the lower limit value shown in FIG. 9A and not more than the upper limit value shown in FIG. 9B, the chromaticity of the background becomes larger than the chromaticity during frontal observation under the conventional ideal conditions. . For example, when the retardation Δnd of the liquid crystal layer 13 is 915 nm and the in-plane retardation Re of the biaxial film 16b is 40 nm, the liquid crystal is observed from the polar angle 60 ° direction in the range of 4 ° to 83 ° counterclockwise from 3 o'clock. When the display surface of the display element is viewed, a background color tone having a chromaticity larger than the chromaticity at the time of frontal observation under conventional ideal conditions is observed.

9A and 9B, it is considered that there is a linear relationship between the lower limit value and upper limit value of the observation azimuth range and the in-plane phase difference Re in each Δnd condition. Therefore, for the lower limit value of the observation azimuth range (FIG. 9A), the plotted lower limit value θ _l is fitted by the least square method of the linear model θ _l = a × Re + b in each Δnd condition, and in each Δnd condition. The values of the coefficients a and b were calculated.

  The calculation results are shown in FIGS. 10A and 10B. FIG. 10A plots the calculation result (value of coefficient a when Δnd = 885 nm, 900 nm, 915 nm, 930 nm, 945 nm, and 960 nm) with Δnd (unit “nm”) on the horizontal axis and coefficient a on the vertical axis. . In FIG. 10B, the horizontal axis is Δnd (unit “nm”), the vertical axis is coefficient b, and the calculation result (value of coefficient b when Δnd = 885 nm, 900 nm, 915 nm, 930 nm, 945 nm, 960 nm) is shown. Plotted.

Further, the inventor of the present application has a linear model (a = α × (Δnd) + β in the case of FIG. 10A and b = α × (Δnd) in the case of FIG. 10B in each of FIGS. 10A and 10B. It was found that fitting was possible by + β). As a result of calculation using the method of least squares, α = −0.0131 and β = 13.208 are obtained in FIG. 10A, and α = 0.8375 and β = −811.17 in FIG. 10B. It was. That is, the lower limit value θ _l of the observation azimuth range (when observing in the 60 ° polar angle direction) in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal condition is the in-plane retardation Re of the biaxial film 16b. And the retardation Δnd of the liquid crystal layer 13, the following formula (3)
It was found that

The same calculation was performed for the upper limit value θ _u (FIG. 9B) of the observation azimuth range.

In FIG. 9B, for each Δnd condition, the plotted upper limit value θ _u was fitted by the least square method of the linear model θ _u = a × Re + b, and the values of the coefficients a and b in each Δnd condition were calculated.

  The calculation results are shown in FIGS. 10C and 10D. In FIG. 10C, the calculation result (value of coefficient a when Δnd = 900 nm, 915 nm, 930 nm, 945 nm, and 960 nm) is plotted with the horizontal axis being Δnd (unit “nm”) and the vertical axis being the coefficient a. FIG. 10D plots the calculation result (value of coefficient b when Δnd = 900 nm, 915 nm, 930 nm, 945 nm, and 960 nm) with Δnd (unit “nm”) on the horizontal axis and coefficient b on the vertical axis. .

The inventor of the present application further shows that in each of FIG. 10C and FIG. 10D, the plot is a linear model (a = α × (Δnd) + β in the case of FIG. 10C, b = α × (Δnd) in the case of FIG. 10D. It was found that fitting was possible by + β). As a result of calculation using the method of least squares, α = 0.0107 and β = -10.94 are obtained in FIG. 10C, and α = −0.6622 and β = 736.51 are obtained in FIG. 10D. It was. That is, the upper limit value θ _u of the observation azimuth range (when observing in the direction of the polar angle of 60 °) where the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal condition is the in-plane retardation Re of the biaxial film 16b. And the retardation Δnd of the liquid crystal layer 13, the following formula (4)
It was found that

Under the observation azimuth range where the lower limit value is θ _l and the upper limit value is θ _u , and the Re and Δnd conditions, a neutral to brown background color tone that does not contain many short wavelength components is observed when the polar angle is 60 °. Is done.

  The inventors of the present application continued to further study.

FIG. 11A shows the lower limit value θ _l and the upper limit value of the observation azimuth range (when observing in the 60 ° polar angle direction) in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal conditions under each Re and Δnd conditions. It is a table | surface which shows (theta) _u again.

  As described above, the conventional ideal conditions in the panel configuration of the second simulation are the in-plane retardation Re = 50 nm of the biaxial film 16b and the retardation Δnd of the liquid crystal layer 13 = 870 nm. Further, as described in “Background Art”, there is a demand that the retardation Δnd of the liquid crystal layer 13 should not be smaller than the conventional ideal condition.

In the table of FIG. 11A, an asterisk (*) is added to the range of the lower limit value θ _l to the upper limit value θ _u where the retardation Δnd of the liquid crystal layer 13 is smaller than the conventional ideal condition.

Further, the range including 0 ° between the lower limit value θ _l and the upper limit value θ _u is considered to be a range including the configuration of the conventional liquid crystal display device.

In the table of FIG. 11A, an asterisk (*) is attached to the observation azimuth range (excluding the range marked with *) including 0 ° between the lower limit value θ ₁ and the upper limit value θ _u .

  FIG. 11B is a table in which the range marked with an asterisk (*) or an American mark (*) is excluded from the table of FIG. 11A.

It can be seen that both the lower limit value θ _l and the upper limit value θ _u are positive values.

For example in a panel configuration of the second simulation, the Re shown in this table, and apply the Δnd conditions, corresponding observations orientation (lower limit theta _l above, the following observations azimuth limit theta _u) from polar angle 60 ° direction When the display surface of the liquid crystal display element is observed, a background color tone having a chromaticity larger than the chromaticity during frontal observation under the conventional ideal condition is observed. Further, Δnd applied has a value equal to or higher than the retardation of the liquid crystal layer under the conventional ideal conditions.

For this reason, in the liquid crystal display device, the liquid crystal display element is rotated in the reverse direction (clockwise direction) by an angle not less than the lower limit value θ _{l and not} more than the upper limit value θ _u , for example. A liquid crystal display device having Δnd equal to or higher than the retardation, and that suppresses light leakage of light on the short wavelength side and reduces the blueness of the background display state at least in the left-right direction (3 o'clock to 9 o'clock direction). It is feasible.

Here, the lower limit value θ _l is a positive value and is represented by the following equation (3).

The upper limit value θ _u is a positive value that satisfies θ _l <θ _u and is represented by the following equation (4).

  7B and FIG. 11B, the second simulation condition (the biaxial film 16b has a thickness direction retardation of 220 nm, the C plate 16a has a thickness direction retardation of 440 nm, and the Re of the conventional ideal conditions) Is 50 nm), compared to the first simulation conditions (the biaxial film 16b has a thickness direction retardation of 440 nm, the C plate 16a has a thickness direction retardation of 220 nm, and Re is 45 nm in the conventional ideal condition). It can be seen that the condition under which the blueness of the background display state is reduced in the azimuth is shifted to a lower region with reference to Re in the conventional ideal condition.

FIG. 11C shows a preferable lower limit value θ _l to upper limit value when the liquid crystal display element is rotated in the reverse direction (clockwise direction) by, for example, an angle not less than the lower limit value θ _{l and not} more than the upper limit value θ _u in the liquid crystal display device. It is a table | surface which shows the range of (theta) _u . This table is created by changing the upper limit value θ _u to 25 ° when the upper limit value θ _u shown in the table of FIG. 11B exceeds 25 °, and the upper limit value θ _{u is set} to 25 °. Are marked with a sharp (#).

For example, when a vertically aligned liquid crystal display element of monodomain alignment is rotated in a range exceeding 25 °, it is assumed that the asymmetry of the light transmittance appears remarkably during the left and right observation of bright display. For this reason, when the value of the upper limit value θ _u exceeds 25 °, the display quality can be improved by setting the upper limit value θ _u to 25 ° (the rotation angle is set to 25 ° or less).

  In the second simulation, in the first panel configuration, the thickness direction retardation of the biaxial film 16b is 220 nm and the thickness direction retardation of the C plate 16a is 440 nm. However, in the second panel configuration and the third panel configuration, It was found that substantially equivalent results were obtained when the thickness direction retardation of the biaxial film 16b was 220 nm and the thickness direction retardation of the C plate 16a was 440 nm.

  Based on the knowledge obtained by the second simulation or the like, for example, the following liquid crystal display device can be used as the liquid crystal display device according to the second embodiment.

Also any liquid crystal display device according to the second embodiment, like the liquid crystal display device according to the first embodiment, the liquid crystal display device of the first panel configuration (see FIG. 1), for example, the lower limit value theta _l above, the following upper limit theta _u The liquid crystal display device is rotated clockwise by an angle θ. Both the lower limit value θ _l and the upper limit value θ _u are positive angles and satisfy θ _l <θ _u . Here, the units of θ, θ _l , and θ _u are all “°”.

  The liquid crystal display device according to the second embodiment is different from the liquid crystal display device according to the first embodiment in that the thickness direction retardation of the C plate 16a is 440 nm and the thickness direction retardation of the biaxial film 16b is 220 nm. Different.

Further, the lower limit value θ _l and the upper limit value θ _u are different from the liquid crystal display device according to the first embodiment in that they are expressed by the following formulas (3) and (4).

  The other points are the same as those of the liquid crystal display device according to the first embodiment.

  The display area (display surface) of the liquid crystal display device according to the second embodiment also has, for example, an upward direction of 12:00, a downward direction of 6 o'clock, a right direction of 3 o'clock, and a left direction of 9 o'clock. The liquid crystal display device according to the second embodiment is also arranged, for example, on a console between a driver seat and a passenger seat in an automobile.

  Further, also in the liquid crystal display device according to the second embodiment, the central molecular orientation direction of the liquid crystal layer 13 is (270-θ) °, and the clockwise direction from the right direction (3 o'clock direction) of the display region by (90 + θ) °. It is the direction rotated in the direction. The absorption axis orientation of the crossed Nicols polarizing plates 17 and 18 is an orientation that forms an angle of 45 ° with the central molecular orientation orientation of the liquid crystal layer 13. For example, the absorption axis orientation of the upper polarizing plate 17 is (135−θ) ° − (315 The −θ) ° azimuth and the lower polarizer 18 absorption axis azimuth are (45−θ) ° − (225−θ) ° azimuth.

  The liquid crystal display device according to the second embodiment is also a liquid crystal display device having good display quality. For example, light leakage of light on the short wavelength side is suppressed at 60 ° oblique observation at least in the left-right direction (3 o'clock to 9 o'clock direction) with Δnd equal to or higher than the retardation of the liquid crystal layer under conventional ideal conditions, and the background This is a liquid crystal display device in which the blueness of the display state is reduced. For example, a brown background color tone can be realized in the horizontal direction.

  The angle θ is preferably 25 ° or less. By setting θ to 25 ° or less, it is possible to suppress the appearance of asymmetry of the light transmittance in the horizontal direction during bright display.

  In the liquid crystal display device according to the second embodiment, the central molecular orientation direction of the liquid crystal layer 13 is the direction rotated clockwise by (90 + θ) ° from the right direction of the display area, but is not limited to the right direction of the display area. Alternatively, a direction rotated clockwise by (90 + θ) ° from the first direction for reducing the bluishness of the background color tone may be used.

Further, the liquid crystal display element of the first panel configuration (see FIG. 1) (the liquid crystal display element in which the C plate 16a and the biaxial film 16b are disposed between the lower substrate 12 and the lower polarizing plate 18) is set to the lower limit value θ _l. above, not only the liquid crystal display device is rotated in the clockwise direction by an angle of less than theta upper limit theta _u, during a second panel constituting the liquid crystal display device (the upper substrate 11 and the upper polarizing plate 17 (see FIG. 2) A liquid crystal display element in which a C plate 16a is arranged and a biaxial film 16b is arranged between the lower substrate 12 and the lower polarizing plate 18), and a liquid crystal display element (see FIG. 3) in the third panel configuration (see FIG. 3) A liquid crystal display element in which a biaxial film 16b is disposed between the upper polarizing plates 17 and a C plate 16a is disposed between the lower substrate 12 and the lower polarizing plate 18 is, for example, a lower limit value _θl or more and an upper limit value θ. Rotate clockwise by angle θ less than _u A liquid crystal display device can be provided.

  Further, the thickness direction retardation of the biaxial film 16b may be in the range of 220 nm ± 10 nm (210 nm to 230 nm), and the thickness direction retardation of the C plate 16a may be in the range of 440 nm ± 10 nm (430 nm to 450 nm). The same effect as that when the thickness direction retardation of the biaxial film 16b is 220 nm and the thickness direction retardation of the C plate 16a is 440 nm will be exhibited.

[Third simulation and third embodiment]
In the first panel configuration, a third simulation in which the thickness direction retardation of the biaxial film 16b is 125 nm and the thickness direction retardation of the C plate 16a is 535 nm will be described.

  First, from a direction orthogonal to the central molecular alignment direction (6 o'clock direction) of the liquid crystal layer 13 and 45 ° with the absorption axis direction of the crossed Nicols polarizing plates 17 and 18, for example, from the polar angle 60 ° direction of the 3 o'clock direction A simulation analysis was performed on the viewing angle compensation condition (conventional ideal condition) in which the background light transmittance was the lowest when observed. As a result, the in-plane retardation Re = 65 nm of the biaxial film 16b and the retardation Δnd = 870 nm of the liquid crystal layer 13 were obtained.

  Next, the in-plane retardation Re of the biaxial film 16b and the retardation Δnd of the liquid crystal layer 13 are variously changed, and the background light transmittance when tilted from the front to the polar angle 60 ° (from the polar angle 60 ° direction) The observation orientation dependency of the observed background light transmittance) was calculated. The observation azimuth is expressed as an angle formed with respect to the 3 o'clock (0 °) azimuth. When viewed from the upper polarizing plate 17 side (Z-axis positive direction), the observation direction is a positive angle when it is counterclockwise from the 3 o'clock direction, and is a negative angle when it is clockwise from the 3 o'clock direction.

  Further, from the calculation result of the dependency of the background light transmittance on the observation direction, an observation direction range in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal condition was calculated.

  12A and 12B are graphs showing the lower limit value and the upper limit value of the observation azimuth range in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal conditions. The horizontal axis of both graphs represents the in-plane retardation Re of the biaxial film 16b in the unit “nm”. The vertical axis of the graph shown in FIG. 12A represents the lower limit value of the observation azimuth range in which the chromaticity is larger than the chromaticity at the time of frontal observation under the conventional ideal condition in the unit “°”. The vertical axis represents the upper limit value of the observation azimuth range in the unit “°”. In both graphs, the retardation Δnd of the liquid crystal layer 13 is shown as a parameter. For example, a triangular plot shows the relationship between the in-plane retardation Re of the biaxial film 16b when Δnd = 900 nm and the lower and upper limits of the observation azimuth range.

  In observation from the polar angle of 60 ° in the observation azimuth range not less than the lower limit value shown in FIG. 12A and not more than the upper limit value shown in FIG. 12B, the chromaticity of the background becomes larger than the chromaticity during frontal observation under the conventional ideal conditions. . For example, when the retardation Δnd of the liquid crystal layer 13 is 900 nm and the in-plane retardation Re = 55 nm of the biaxial film 16b, the liquid crystal is observed from the polar angle 60 ° direction in the range of 7 ° to 77 ° counterclockwise from 3 o'clock. When the display surface of the display element is viewed, a background color tone having a chromaticity larger than the chromaticity at the time of frontal observation under conventional ideal conditions is observed.

From FIG. 12A and FIG. 12B, it is considered that there is a linear relationship between the lower limit value and upper limit value of the observation azimuth range and the in-plane phase difference Re under each Δnd condition. Therefore, for the lower limit value of the observation azimuth range (FIG. 12A), the plotted lower limit value θ _l is fitted by the least square method of the linear model θ _l = a × Re + b in each Δnd condition, and in each Δnd condition. The values of the coefficients a and b were calculated.

  FIG. 13A and FIG. 13B show the calculation results. In FIG. 13A, the horizontal axis is Δnd (unit “nm”), and the vertical axis is the coefficient a, and the calculation result (value of coefficient a when Δnd = 885 nm, 900 nm, 915 nm, 930 nm, and 945 nm) is plotted. FIG. 13B plots the calculation result (value of coefficient b when Δnd = 885 nm, 900 nm, 915 nm, 930 nm, and 945 nm) with Δnd (unit “nm”) on the horizontal axis and coefficient b on the vertical axis. .

The inventor of the present application further shows that in each of FIGS. 13A and 13B, the plot is a quadratic function model (a = α × (Δnd) ² + β × (Δnd) + γ in the case of FIG. 13A, B = α × (Δnd) ² + β × (Δnd) + γ), and found that curve fitting is possible. As a result of calculation using the least squares method, α = −0.0004, β = 0.7479, γ = −336.65 in FIG. 13A, and α = 0.016, β = −28 in FIG. 13B. .45, γ = 12507. That is, the lower limit value θ _l of the observation azimuth range (when observing in the 60 ° polar angle direction) in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal condition is the in-plane retardation Re of the biaxial film 16b. And the retardation Δnd of the liquid crystal layer 13, the following formula (5)
It was found that

The same calculation was performed for the upper limit value θ _u (FIG. 12B) of the observation azimuth range.

In FIG. 12B, for each Δnd condition, the plotted upper limit value θ _u was fitted by the least square method of the linear model θ _u = a × Re + b, and the values of the coefficients a and b in each Δnd condition were calculated.

  The calculation results are shown in FIGS. 13C and 13D. In FIG. 13C, the horizontal axis is Δnd (unit “nm”) and the vertical axis is the coefficient a, and the calculation results (values of the coefficient a when Δnd = 900 nm, 915 nm, 930 nm, 945 nm, and 960 nm) are plotted. FIG. 13D plots the calculation result (value of coefficient b when Δnd = 900 nm, 915 nm, 930 nm, 945 nm, and 960 nm) with Δnd (unit “nm”) on the horizontal axis and coefficient b on the vertical axis. .

Further, the inventor of the present application has a quadratic function model (a = α × (Δnd) ² + β × (Δnd) + γ in the case of FIG. 13C, and FIG. 13D in each of FIGS. 13C and 13D). B = α × (Δnd) ² + β × (Δnd) + γ), and found that curve fitting is possible. As a result of calculation using the least square method, α = −0.0003, β = 0.05057, γ = −252.72 in FIG. 13C, and α = 0.0177, β = −34 in FIG. 13D. 918, γ = 17369. That is, the upper limit value θ _u of the observation azimuth range (when observing in the direction of the polar angle of 60 °) where the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal condition is the in-plane retardation Re of the biaxial film 16b. , And the retardation Δnd of the liquid crystal layer 13, the following formula (6)
It was found that

Under the observation azimuth range where the lower limit value is θ _l and the upper limit value is θ _u , and the Re and Δnd conditions, a neutral to brown background color tone that does not contain many short wavelength components is observed when the polar angle is 60 °. Is done.

  The inventors of the present application continued to further study.

FIG. 14A shows the lower limit value θ _l and the upper limit value of the observation azimuth range (when observing in the polar angle 60 ° direction) in which the chromaticity is larger than the chromaticity during frontal observation under conventional ideal conditions under each Re and Δnd conditions. It is a table | surface which shows (theta) _u again.

  As described above, the conventional ideal conditions in the panel configuration of the third simulation are the in-plane retardation Re = 65 nm of the biaxial film 16b and the retardation Δnd of the liquid crystal layer 13 = 870 nm. Further, as described in “Background Art”, there is a demand that the retardation Δnd of the liquid crystal layer 13 should not be smaller than the conventional ideal condition.

In the table of FIG. 14A, an asterisk (*) is added to the range of the lower limit value θ _l to the upper limit value θ _u where the retardation Δnd of the liquid crystal layer 13 is smaller than the conventional ideal condition.

Further, the range including 0 ° between the lower limit value θ _l and the upper limit value θ _u is considered to be a range including the configuration of the conventional liquid crystal display device.

In the table of FIG. 14A, an asterisk (*) is added to the observation azimuth range (excluding the range marked with *) including 0 ° between the lower limit value θ _l and the upper limit value θ _u .

  FIG. 14B is a table in which the range marked with an asterisk (*) or an American mark (*) is excluded from the table of FIG. 14A.

It can be seen that both the lower limit value θ _l and the upper limit value θ _u are positive values.

For example, in the panel configuration of the third simulation, the Re and Δnd conditions shown in this table are applied, and the corresponding observation azimuth (observation azimuth not less than the lower limit value θ _{l and not} more than the upper limit value θ _u ) is viewed from the direction of the polar angle 60 °. When the display surface of the liquid crystal display element is observed, a background color tone having a chromaticity larger than the chromaticity during frontal observation under the conventional ideal condition is observed. Further, Δnd applied has a value equal to or higher than the retardation of the liquid crystal layer under the conventional ideal conditions.

For this reason, in the liquid crystal display device, the liquid crystal display element is rotated in the reverse direction (clockwise direction) by an angle not less than the lower limit value θ _{l and not} more than the upper limit value θ _u , for example. A liquid crystal display device having Δnd equal to or higher than the retardation, and that suppresses light leakage of light on the short wavelength side and reduces the blueness of the background display state at least in the left-right direction (3 o'clock to 9 o'clock direction). It is feasible.

Here, the lower limit value θ _l is a positive value and is represented by the following equation (5).

The upper limit value θ _u is a positive value that satisfies θ _l <θ _u and is represented by the following equation (6).

FIG. 14C shows a preferable lower limit value θ _l to upper limit value when the liquid crystal display element is rotated in the reverse direction (clockwise direction) by an angle not less than the lower limit value θ _{l and not} more than the upper limit value θ _u in the liquid crystal display device, for example. It is a table | surface which shows the range of (theta) _u . This table changes the upper limit value θ _u to 25 ° when the value of the upper limit value θ _u shown in the table of FIG. 14B exceeds 25 ° (when the value of the lower limit value θ _l does not exceed 25 °). created by, given the pound (#) the upper limit theta _u in the column was 25 °. Further, when the value of the lower limit value θ _l exceeds 25 °, a strikethrough is added to the columns of the lower limit value θ _l and the upper limit value θ _u .

For example, when a vertically aligned liquid crystal display element of monodomain alignment is rotated in a range exceeding 25 °, it is assumed that the asymmetry of the light transmittance appears remarkably during the left and right observation of bright display. Therefore, when the value of the upper limit value θ _u exceeds 25 ° (when the value of the lower limit value θ _l does not exceed 25 °), the upper limit value θ _{u is set} to 25 ° (the rotation angle is 25 ° or less). Display quality can be improved. Note that when the value of the lower limit value θ _l exceeds 25 °, the rotation angle cannot be made 25 ° or less, and this is excluded from the preferable range of the lower limit value θ _l to the upper limit value θ _u .

  Referring to FIG. 7C and FIG. 14C, the third simulation condition (the phase difference in the thickness direction of the biaxial film 16b is 125 nm, the thickness direction of the C plate 16a, when viewed on the basis of Re in the conventional ideal condition. Under the phase difference of 535 nm, Re in the conventional ideal condition is 65 nm, the first simulation condition (the biaxial film 16b has a thickness direction retardation of 440 nm, the C plate 16a has a thickness direction retardation of 220 nm, It can be seen that Re is 45 nm in an ideal condition and the range in which Δnd can be set and the margin for setting the rotation angle are narrow.

  In the third simulation, in the first panel configuration, the thickness direction retardation of the biaxial film 16b is 125 nm and the thickness direction retardation of the C plate 16a is 535 nm. However, in the second panel configuration and the third panel configuration, It was found that substantially equivalent results were obtained when the thickness direction retardation of the biaxial film 16b was 125 nm and the thickness direction retardation of the C plate 16a was 535 nm.

  Based on the knowledge obtained by the third simulation or the like, for example, the following liquid crystal display device can be used as the liquid crystal display device according to the third embodiment.

Also any liquid crystal display device according to the third embodiment, like the liquid crystal display device according to the first embodiment, the liquid crystal display device of the first panel configuration (see FIG. 1), for example, the lower limit value theta _l above, the following upper limit theta _u The liquid crystal display device is rotated clockwise by an angle θ. Both the lower limit value θ _l and the upper limit value θ _u are positive angles and satisfy θ _l <θ _u . Here, the units of θ, θ _l , and θ _u are all “°”.

  The liquid crystal display device according to the third embodiment is different from the liquid crystal display device according to the first embodiment in that the thickness direction retardation of the C plate 16a is 535 nm and the thickness direction retardation of the biaxial film 16b is 125 nm. Different.

Further, the lower limit value θ _l and the upper limit value θ _u are different from the liquid crystal display device according to the first embodiment in that they are expressed by the following formulas (5) and (6).

  The other points are the same as those of the liquid crystal display device according to the first embodiment.

  The display area (display surface) of the liquid crystal display device according to the third embodiment also has, for example, an upward direction of 12:00, a downward direction of 6 o'clock, a right direction of 3 o'clock, and a left direction of 9 o'clock. The liquid crystal display device according to the third embodiment is also arranged, for example, on a console between a driver seat and a passenger seat in an automobile.

  Further, also in the liquid crystal display device according to the third embodiment, the central molecular orientation of the liquid crystal layer 13 is (270-θ) °, and the clockwise direction from the right direction (3 o'clock) of the display region by (90 + θ) °. It is the direction rotated in the direction. The absorption axis orientation of the crossed Nicols polarizing plates 17 and 18 is an orientation that forms an angle of 45 ° with the central molecular orientation orientation of the liquid crystal layer 13. For example, the absorption axis orientation of the upper polarizing plate 17 is (135−θ) ° − (315 The −θ) ° azimuth and the lower polarizer 18 absorption axis azimuth are (45−θ) ° − (225−θ) ° azimuth.

  The liquid crystal display device according to the third embodiment is also a liquid crystal display device having good display quality. For example, light leakage of light on the short wavelength side is suppressed at 60 ° oblique observation at least in the left-right direction (3 o'clock to 9 o'clock direction) with Δnd equal to or higher than the retardation of the liquid crystal layer under conventional ideal conditions, and the background This is a liquid crystal display device in which the blueness of the display state is reduced. For example, a brown background color tone can be realized in the horizontal direction.

  The angle θ is preferably 25 ° or less. By setting θ to 25 ° or less, it is possible to suppress the appearance of asymmetry of the light transmittance in the horizontal direction during bright display.

  In the liquid crystal display device according to the third embodiment, the central molecular orientation of the liquid crystal layer 13 is the direction rotated clockwise by (90 + θ) ° from the right direction of the display area, but is not limited to the right direction of the display area. Alternatively, a direction rotated clockwise by (90 + θ) ° from the first direction for reducing the bluishness of the background color tone may be used.

Further, the liquid crystal display element of the first panel configuration (see FIG. 1) (the liquid crystal display element in which the C plate 16a and the biaxial film 16b are disposed between the lower substrate 12 and the lower polarizing plate 18) is set to the lower limit value θ _l. above, not only the liquid crystal display device is rotated in the clockwise direction by an angle of less than theta upper limit theta _u, during a second panel constituting the liquid crystal display device (the upper substrate 11 and the upper polarizing plate 17 (see FIG. 2) A liquid crystal display element in which a C plate 16a is arranged and a biaxial film 16b is arranged between the lower substrate 12 and the lower polarizing plate 18), and a liquid crystal display element (see FIG. 3) in the third panel configuration (see FIG. 3) A liquid crystal display element in which a biaxial film 16b is disposed between the upper polarizing plates 17 and a C plate 16a is disposed between the lower substrate 12 and the lower polarizing plate 18 is, for example, a lower limit value _θl or more and an upper limit value θ. Rotate clockwise by angle θ less than _u A liquid crystal display device can be provided.

  Further, the thickness direction retardation of the biaxial film 16b may be in the range of 125 nm ± 10 nm (115 nm to 135 nm), and the thickness direction retardation of the C plate 16a may be in the range of 535 nm ± 10 nm (525 nm to 545 nm). The same effect as the case where the thickness direction retardation of the biaxial film 16b is 125 nm and the thickness direction retardation of the C plate 16a is 535 nm will be exhibited.

[Fourth simulation and fourth embodiment]
In the first panel configuration, the thickness direction retardation of the biaxial film 16b is set to 660 nm, and the C plate 16a is not disposed (the viewing angle compensation plate 16 is configured only by the biaxial film 16b having a thickness direction retardation of 660 nm). 4 Simulation will be described.

  First, from a direction orthogonal to the central molecular alignment direction (6 o'clock direction) of the liquid crystal layer 13 and 45 ° with the absorption axis direction of the crossed Nicols polarizing plates 17 and 18, for example, from the polar angle 60 ° direction of the 3 o'clock direction A simulation analysis was performed on the viewing angle compensation condition (conventional ideal condition) in which the background light transmittance was the lowest when observed. As a result, the in-plane retardation Re = 35 nm of the biaxial film 16b and the retardation Δnd = 870 nm of the liquid crystal layer 13 were obtained.

  Next, the in-plane retardation Re of the biaxial film 16b and the retardation Δnd of the liquid crystal layer 13 are variously changed, and the background light transmittance when tilted from the front to the polar angle 60 ° (from the polar angle 60 ° direction) The observation orientation dependency of the observed background light transmittance) was calculated. The observation azimuth is expressed as an angle formed with respect to the 3 o'clock (0 °) azimuth. When viewed from the upper polarizing plate 17 side (Z-axis positive direction), the observation direction is a positive angle when it is counterclockwise from the 3 o'clock direction, and is a negative angle when it is clockwise from the 3 o'clock direction.

  Further, from the calculation result of the dependency of the background light transmittance on the observation direction, an observation direction range in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal condition was calculated.

  FIG. 15A and FIG. 15B are graphs showing the lower limit value and upper limit value of the observation azimuth range in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal conditions. The horizontal axis of both graphs represents the in-plane retardation Re of the biaxial film 16b in the unit “nm”. The vertical axis of the graph shown in FIG. 15A represents the lower limit value of the observation azimuth range in which the chromaticity is larger than the chromaticity at the time of frontal observation under the conventional ideal condition in the unit “°”. The vertical axis represents the upper limit value of the observation azimuth range in the unit “°”. In both graphs, the retardation Δnd of the liquid crystal layer 13 is shown as a parameter. For example, a triangular plot shows the relationship between the in-plane retardation Re of the biaxial film 16b when Δnd = 855 nm, the lower limit value and the upper limit value of the observation azimuth range.

  In the observation from the polar angle of 60 ° in the observation azimuth range not less than the lower limit value shown in FIG. 15A and not more than the upper limit value shown in FIG. 15B, the chromaticity of the background becomes larger than the chromaticity during frontal observation under the conventional ideal conditions. . For example, when the retardation Δnd of the liquid crystal layer 13 is 870 nm and the in-plane retardation Re of the biaxial film 16b is 30 nm, the liquid crystal is viewed from the polar angle 60 ° direction in the range of 2 ° to 7 ° counterclockwise from 3 o'clock. When the display surface of the display element is viewed, a background color tone having a chromaticity larger than the chromaticity at the time of frontal observation under conventional ideal conditions is observed.

From FIG. 15A and FIG. 15B, it is considered that there is a linear relationship between the lower limit value and upper limit value of the observation azimuth range and the in-plane phase difference Re under each Δnd condition. Therefore, for the lower limit value of the observation azimuth range (FIG. 15A), the plotted lower limit value θ _l is fitted by the least square method of the linear model θ _l = a × Re + b in each Δnd condition, and in each Δnd condition. The values of the coefficients a and b were calculated.

  FIG. 16A and FIG. 16B show the calculation results. In FIG. 16A, the calculation result (value of coefficient a when Δnd = 825 nm, 840 nm, 855 nm, and 870 nm) is plotted with Δnd (unit “nm”) on the horizontal axis and coefficient a on the vertical axis. In FIG. 16B, the calculation result (value of coefficient b when Δnd = 825 nm, 840 nm, 855 nm, and 870 nm) is plotted with the horizontal axis being Δnd (unit “nm”) and the vertical axis being the coefficient b.

The inventor of the present application further shows that in each of FIGS. 16A and 16B, the plot is a quadratic function model (in the case of FIG. 16A, a = α × (Δnd) ² + β × (Δnd) + γ, in the case of FIG. 16B. B = α × (Δnd) ² + β × (Δnd) + γ), and found that curve fitting is possible. As a result of calculation using the least square method, α = −0.0004, β = 0.7667, γ = −331.4 in FIG. 16A, and α = 0.0133, β = −22 in FIG. 16B. .627, γ = 969.1. That is, the lower limit value θ _l of the observation azimuth range (when observing in the 60 ° polar angle direction) in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal condition is the in-plane retardation Re of the biaxial film 16b. , And the retardation Δnd of the liquid crystal layer 13, the following formula (7)
It was found that

The same calculation was performed for the upper limit value θ _u (FIG. 15B) of the observation azimuth range.

In FIG. 15B, for each Δnd condition, the plotted upper limit value θ _u was fitted by the least square method of the linear model θ _u = a × Re + b, and the values of the coefficients a and b in each Δnd condition were calculated.

  FIG. 16C and FIG. 16D show the calculation results. In FIG. 16C, the horizontal axis is Δnd (unit “nm”) and the vertical axis is the coefficient a, and the calculation result (value of coefficient a when Δnd = 825 nm, 840 nm, 855 nm, and 870 nm) is plotted. In FIG. 16D, the calculation result (value of coefficient b when Δnd = 825 nm, 840 nm, 855 nm, and 870 nm) is plotted with the horizontal axis being Δnd (unit “nm”) and the vertical axis being the coefficient b.

The inventor of the present application further shows that in each of FIG. 16C and FIG. 16D, the plot is a quadratic function model (a = α × (Δnd) ² + β × (Δnd) + γ in the case of FIG. 16C, B = α × (Δnd) ² + β × (Δnd) + γ), and found that curve fitting is possible. As a result of calculation using the least square method, α = 0.0002, β = −0.354, γ = 141.39 in FIG. 16C, and α = −0.0078, β = 12. 55, γ = −5072.8. That is, the upper limit value θ _u of the observation azimuth range (when observing in the direction of the polar angle of 60 °) where the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal condition is the in-plane retardation Re of the biaxial film 16b. And the retardation Δnd of the liquid crystal layer 13, the following formula (8)
It was found that

Under the observation azimuth range where the lower limit value is θ _l and the upper limit value is θ _u , and the Re and Δnd conditions, a neutral to brown background color tone that does not contain many short wavelength components is observed when the polar angle is 60 °. Is done.

  The inventors of the present application continued to further study.

FIG. 17A shows a lower limit value θ _l and an upper limit value of the observation azimuth range (when observing in the direction of a polar angle of 60 °) in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal conditions under each Re and Δnd conditions. It is a table | surface which shows (theta) _u again.

  As described above, the conventional ideal conditions in the panel configuration of the fourth simulation are the in-plane retardation Re = 35 nm of the biaxial film 16b and the retardation Δnd of the liquid crystal layer 13 = 870 nm. Further, as described in “Background Art”, there is a demand that the retardation Δnd of the liquid crystal layer 13 should not be smaller than the conventional ideal condition.

In the table of FIG. 17A, an asterisk (*) is added to the range of the lower limit value θ _l to the upper limit value θ _u where the retardation Δnd of the liquid crystal layer 13 is smaller than the conventional ideal condition.

Further, the range including 0 ° between the lower limit value θ _l and the upper limit value θ _u is considered to be a range including the configuration of the conventional liquid crystal display device.

In the table of FIG. 17A, an asterisk (*) is attached to the observation azimuth range (excluding the range marked with *) including 0 ° between the lower limit value θ _l and the upper limit value θ _u .

  FIG. 17B is a table in which the range marked with an asterisk (*) or an American mark (*) is excluded from the table of FIG. 17A.

It can be seen that both the lower limit value θ _l and the upper limit value θ _u are positive values.

For example in a panel configuration of the fourth simulation, each Re is shown in this table, and apply the Δnd conditions, corresponding observations orientation (lower limit theta _l above, the following observations azimuth limit theta _u) from polar angle 60 ° direction When the display surface of the liquid crystal display element is observed, a background color tone having a chromaticity larger than the chromaticity during frontal observation under the conventional ideal condition is observed. Further, Δnd applied has a value equal to or higher than the retardation of the liquid crystal layer under the conventional ideal conditions.

For this reason, in the liquid crystal display device, the liquid crystal display element is rotated in the reverse direction (clockwise direction) by an angle not less than the lower limit value θ _{l and not} more than the upper limit value θ _u , for example. A liquid crystal display device having Δnd equal to or higher than the retardation, and that suppresses light leakage of light on the short wavelength side and reduces the blueness of the background display state at least in the left-right direction (3 o'clock to 9 o'clock direction). It is feasible.

Here, the lower limit value θ _l is a positive value and is represented by the following equation (7).

The upper limit value θ _u is a positive value that satisfies θ _l <θ _u and is represented by the following equation (8).

  When comparing FIG. 7B, FIG. 11B, FIG. 14B and FIG. 17B, it can be seen that the range in which Δnd and the rotation angle can be set is narrow under the conditions of the fourth simulation.

Note that when the monodomain aligned vertical alignment type liquid crystal display element is rotated in a range exceeding 25 °, it is assumed that the asymmetry of the light transmittance appears remarkably during the right and left observation of the bright display. It is preferable to set it to 0 ° or less. By doing so, display quality can be improved. However, there is no angle exceeding 25 ° in the range of the lower limit value θ _l to the upper limit value θ _u shown in FIG. 17B.

  In the fourth simulation, in the first panel configuration, the thickness direction retardation of the biaxial film 16b is set to 660 nm and the C plate 16a is not used. However, in the third panel configuration, the thickness direction of the biaxial film 16b is used. It was found that even when the phase difference was 660 nm and the C plate 16a was not used, almost the same result was obtained.

  Based on the knowledge obtained by the fourth simulation or the like, for example, the following liquid crystal display device can be used as the liquid crystal display device according to the fourth embodiment.

Similarly to the liquid crystal display device according to the first embodiment, the liquid crystal display device according to the fourth embodiment also has the first panel configuration (see FIG. 1. However, in the liquid crystal display device according to the fourth embodiment, the C plate 16a is used. No.) is rotated in the clockwise direction by an angle θ not less than the lower limit θ _{l and not} more than the upper limit θ _u , for example. Both the lower limit value θ _l and the upper limit value θ _u are positive angles and satisfy θ _l <θ _u . Here, the units of θ, θ _l , and θ _u are all “°”.

  The liquid crystal display device according to the fourth embodiment differs from the liquid crystal display device according to the first embodiment in that the C plate 16a is not disposed and the thickness direction retardation of the biaxial film 16b is 660 nm.

Further, the lower limit value θ _l and the upper limit value θ _u are different from the liquid crystal display device according to the first embodiment in that they are expressed by the following formulas (7) and (8).

  The other points are the same as those of the liquid crystal display device according to the first embodiment.

  The display area (display surface) of the liquid crystal display device according to the fourth embodiment also has, for example, an upward direction of 12:00, a downward direction of 6 o'clock, a right direction of 3 o'clock, and a left direction of 9 o'clock. The liquid crystal display device according to the fourth embodiment is also arranged, for example, on a console between a driver seat and a passenger seat in an automobile.

  Further, also in the liquid crystal display device according to the fourth embodiment, the central molecular orientation of the liquid crystal layer 13 is (270-θ) °, and clockwise from the right direction (3 o'clock) of the display region by (90 + θ) °. It is the direction rotated in the direction. The absorption axis orientation of the crossed Nicols polarizing plates 17 and 18 is an orientation that forms an angle of 45 ° with the central molecular orientation orientation of the liquid crystal layer 13. For example, the absorption axis orientation of the upper polarizing plate 17 is (135−θ) ° − (315 The −θ) ° azimuth and the lower polarizer 18 absorption axis azimuth are (45−θ) ° − (225−θ) ° azimuth.

  The liquid crystal display device according to the fourth embodiment is also a liquid crystal display device having good display quality. For example, light leakage of light on the short wavelength side is suppressed at 60 ° oblique observation at least in the left-right direction (3 o'clock to 9 o'clock direction) with Δnd equal to or higher than the retardation of the liquid crystal layer under conventional ideal conditions, and the background This is a liquid crystal display device in which the blueness of the display state is reduced. For example, a brown background color tone can be realized in the horizontal direction.

  The angle θ is preferably 25 ° or less. By setting θ to 25 ° or less, it is possible to suppress the appearance of asymmetry of the light transmittance in the horizontal direction during bright display.

  In the liquid crystal display device according to the fourth embodiment, the central molecular orientation direction of the liquid crystal layer 13 is the direction rotated clockwise by (90 + θ) ° from the right direction of the display area, but is not limited to the right direction of the display area. Alternatively, a direction rotated clockwise by (90 + θ) ° from the first direction for reducing the bluishness of the background color tone may be used.

In addition, the liquid crystal display element (between the lower substrate 12 and the lower polarizing plate 18) of the first panel configuration (see FIG. 1; however, the C plate 16a is not used in the liquid crystal display device according to the fourth embodiment). In addition to the liquid crystal display device in which the biaxial film 16b is arranged in the clockwise direction by an angle θ not less than the lower limit θ _{l and not} more than the upper limit θ _u , a third panel configuration (FIG. 3) is used. in the reference), the liquid crystal display device using no C plate 16a (liquid crystal display element disposing a biaxial film 16b between the upper substrate 11 and the upper polarizing plate 17), for example, the lower limit value theta _l or more, more than the upper limit theta _u The liquid crystal display device can also be rotated clockwise by the angle θ.

  Further, the thickness direction retardation of the biaxial film 16b may be in a range of 660 nm ± 10 nm (650 nm to 670 nm). The same effect as the case where the thickness direction retardation of the biaxial film 16b is 660 nm will be exhibited.

  Under the conditions of the first to fourth simulations, the retardation Δnd of the liquid crystal layer 13 under the conventional ideal conditions is all 870 nm. From the results of the first to fourth simulations, the biaxiality is that the observation direction in which the chromaticity at the observation of the polar angle of 60 ° is larger than the chromaticity at the front observation is a relatively small angle and the margin for Δnd is wide. It can be seen that the thickness direction retardation Rth of the film 16b is about 440 nm (first simulation).

[Fifth simulation and fifth embodiment]
In the first panel configuration, the thickness direction retardation of the biaxial film 16b is set to 440 nm, and the C plate 16a is not disposed (the viewing angle compensation plate 16 is configured only by the biaxial film 16b having a thickness direction retardation of 440 nm). 5 Simulation will be described. The analysis target in the fifth simulation is different from that in the fourth simulation in that the thickness direction retardation of the biaxial film 16b is set to 440 nm instead of 660 nm.

  First, from a direction orthogonal to the central molecular alignment direction (6 o'clock direction) of the liquid crystal layer 13 and 45 ° with the absorption axis direction of the crossed Nicols polarizing plates 17 and 18, for example, from the polar angle 60 ° direction of the 3 o'clock direction A simulation analysis was performed on the viewing angle compensation condition (conventional ideal condition) in which the background light transmittance was the lowest when observed. As a result, the in-plane retardation Re = 45 nm of the biaxial film 16b and the retardation Δnd = 610 nm of the liquid crystal layer 13 were obtained. Under the conditions of the fifth simulation, Δnd (610 nm) in the conventional ideal condition is smaller than that (870 nm) in the first to fourth simulations.

  Next, the in-plane retardation Re of the biaxial film 16b and the retardation Δnd of the liquid crystal layer 13 are variously changed, and the background light transmittance when tilted from the front to the polar angle 60 ° (from the polar angle 60 ° direction) The observation orientation dependency of the observed background light transmittance) was calculated. The observation azimuth is expressed as an angle formed with respect to the 3 o'clock (0 °) azimuth. When viewed from the upper polarizing plate 17 side (Z-axis positive direction), the observation direction is a positive angle when it is counterclockwise from the 3 o'clock direction, and is a negative angle when it is clockwise from the 3 o'clock direction.

  Further, from the calculation result of the dependency of the background light transmittance on the observation direction, an observation direction range in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal condition was calculated.

  18A and 18B are graphs showing the lower limit value and the upper limit value of the observation azimuth range in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal condition. The horizontal axis of both graphs represents the in-plane retardation Re of the biaxial film 16b in the unit “nm”. The vertical axis of the graph shown in FIG. 18A represents the lower limit value of the observation azimuth range in which the chromaticity is larger than the chromaticity at the time of frontal observation under the conventional ideal condition in the unit “°”. The vertical axis represents the upper limit value of the observation azimuth range in the unit “°”. In both graphs, the retardation Δnd of the liquid crystal layer 13 is shown as a parameter. For example, a triangular plot shows the relationship between the in-plane retardation Re of the biaxial film 16b when Δnd = 615 nm and the lower and upper limit values of the observation azimuth range.

  In the observation from the polar angle of 60 ° in the observation azimuth range not less than the lower limit value shown in FIG. 18A and not more than the upper limit value shown in FIG. . For example, when the retardation Δnd of the liquid crystal layer 13 is 660 nm and the in-plane retardation Re of the biaxial film 16b is 40 nm, the liquid crystal is viewed from the polar angle 60 ° direction in the range of 4 ° to 16 ° counterclockwise from 3 o'clock. When the display surface of the display element is viewed, a background color tone having a chromaticity larger than the chromaticity at the time of frontal observation under conventional ideal conditions is observed.

18A and 18B, it is considered that there is a linear relationship between the lower limit value and upper limit value of the observation azimuth range and the in-plane phase difference Re in each Δnd condition. Therefore, for the lower limit value of the observation azimuth range (FIG. 18A), the plotted lower limit value θ _l is fitted by the least square method of the linear model θ _l = a × Re + b in each Δnd condition, and in each Δnd condition. The values of the coefficients a and b were calculated.

  FIG. 19A and FIG. 19B show the calculation results. In FIG. 19A, the horizontal axis is Δnd (unit “nm”), the vertical axis is coefficient a, and the calculation result (value of coefficient a when Δnd = 585 nm, 600 nm, 615 nm, 630 nm, 645 nm, 660 nm, and 675 nm) is shown. Plotted. In FIG. 19B, the horizontal axis is Δnd (unit “nm”), the vertical axis is the coefficient b, and the calculation result (Δnd = 585 nm, 600 nm, 615 nm, 630 nm, 645 nm, 660 nm, 675 nm) ) Was plotted.

Further, the inventor of the present application plots the quadratic function model (a = α × (Δnd) ² + β × (Δnd) + γ in the case of FIG. 19A, FIG. 19B in each of FIGS. 19A and 19B). B = α × (Δnd) ² + β × (Δnd) + γ), and found that curve fitting is possible. As a result of calculation using the least square method, α = 9 × 10 ⁻⁵ , β = −0.1226, γ = 42.069 in FIG. 19A, and α = −0.005, β = in FIG. 19B. The results were 6.842, γ = −2365.8. That is, the lower limit value θ _l of the observation azimuth range (when observing in the 60 ° polar angle direction) in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal condition is the in-plane retardation Re of the biaxial film 16b. , And the retardation Δnd of the liquid crystal layer 13, the following formula (9)
It was found that

The same calculation was performed for the upper limit value θ _u (FIG. 18B) of the observation azimuth range.

In FIG. 18B, for each Δnd condition, the plotted upper limit value θ _u was fitted by the least square method of the linear model θ _u = a × Re + b, and the values of the coefficients a and b in each Δnd condition were calculated.

  FIG. 19C and FIG. 19D show the calculation results. FIG. 19C plots the calculation results (values of coefficient a when Δnd = 585 nm, 600 nm, 615 nm, 630 nm, 645 nm, and 660 nm) with Δnd (unit “nm”) on the horizontal axis and coefficient a on the vertical axis. . In FIG. 19D, the horizontal axis is Δnd (unit “nm”), the vertical axis is the coefficient b, and the calculation result (value of coefficient b when Δnd = 585 nm, 600 nm, 615 nm, 630 nm, 645 nm, and 660 nm) is shown. Plotted.

Further, the inventor of the present application plots a quadratic function model (a = α × (Δnd) ² + β × (Δnd) + γ in the case of FIG. 19C, and FIG. 19D in each of FIGS. 19C and 19D). B = α × (Δnd) ² + β × (Δnd) + γ), and found that curve fitting is possible. As a result of calculation using the least squares method, α = −0.0004, β = 0.4389, γ = −135.8 in FIG. 19C, and α = 0.0146, β = −17 in FIG. 19D. .772, γ = 5469.3 were obtained. That is, the upper limit value θ _u of the observation azimuth range (when observing in the direction of the polar angle of 60 °) where the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal condition is the in-plane retardation Re of the biaxial film 16b. And the retardation Δnd of the liquid crystal layer 13, the following formula (10)
It was found that

Under the observation azimuth range where the lower limit value is θ _l and the upper limit value is θ _u , and the Re and Δnd conditions, a neutral to brown background color tone that does not contain many short wavelength components is observed when the polar angle is 60 °. Is done.

  The inventors of the present application continued to further study.

FIG. 20A shows the lower limit value θ _l and the upper limit value of the observation azimuth range (when observing in the polar angle 60 ° direction) in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal conditions under each Re and Δnd conditions. It is a table | surface which shows (theta) _u again.

  As described above, the conventional ideal conditions in the panel configuration of the fifth simulation are the in-plane retardation Re = 45 nm of the biaxial film 16b and the retardation Δnd = 610 nm of the liquid crystal layer 13. Further, as described in “Background Art”, there is a demand that the retardation Δnd of the liquid crystal layer 13 should not be smaller than the conventional ideal condition.

In the table of FIG. 20A, an asterisk (*) is added to the range of the lower limit value θ _l to the upper limit value θ _u where the retardation Δnd of the liquid crystal layer 13 is smaller than the conventional ideal condition.

Further, the range including 0 ° between the lower limit value θ _l and the upper limit value θ _u is considered to be a range including the configuration of the conventional liquid crystal display device.

In the table of FIG. 20A, an asterisk (*) is attached to the observation azimuth range (excluding the range marked with *) including 0 ° between the lower limit value θ ₁ and the upper limit value θ _u .

  FIG. 20B is a table in which the range marked with an asterisk (*) or an American mark (*) is excluded from the table of FIG. 20A.

It can be seen that both the lower limit value θ _l and the upper limit value θ _u are positive values.

For example, in the panel configuration of the fifth simulation, the Re and Δnd conditions shown in this table are applied, and the corresponding observation azimuth (observation azimuth not less than the lower limit θ _{l and not} more than the upper limit θ _u ) is viewed from the direction of the polar angle 60 °. When the display surface of the liquid crystal display element is observed, a background color tone having a chromaticity larger than the chromaticity during frontal observation under the conventional ideal condition is observed. Further, Δnd applied has a value equal to or higher than the retardation of the liquid crystal layer under the conventional ideal conditions.

For this reason, in the liquid crystal display device, the liquid crystal display element is rotated in the reverse direction (clockwise direction) by an angle not less than the lower limit value θ _{l and not} more than the upper limit value θ _u , for example. A liquid crystal display device having Δnd equal to or higher than the retardation, and that suppresses light leakage of light on the short wavelength side and reduces the blueness of the background display state at least in the left-right direction (3 o'clock to 9 o'clock direction). It is feasible.

Here, the lower limit value θ _l is a positive value and is represented by the following equation (9).

The upper limit value θ _u is a positive value that satisfies θ _l <θ _u and is represented by the following equation (10).

FIG. 20C shows a preferable lower limit value θ _l to upper limit value when the liquid crystal display element is rotated in the reverse direction (clockwise direction) by, for example, an angle not less than the lower limit value θ _{l and not} more than the upper limit value θ _u in the liquid crystal display device. It is a table | surface which shows the range of (theta) _u . This table is created by changing the upper limit value θ _u to 25 ° when the upper limit value θ _u shown in the table of FIG. 20B exceeds 25 °, and the upper limit value θ _{u is set} to 25 °. Are marked with a sharp (#).

For example, when a vertically aligned liquid crystal display element of monodomain alignment is rotated in a range exceeding 25 °, it is assumed that the asymmetry of the light transmittance appears remarkably during the left and right observation of bright display. For this reason, when the value of the upper limit value θ _u exceeds 25 °, the display quality can be improved by setting the upper limit value θ _u to 25 ° (the rotation angle is set to 25 ° or less).

  In the fifth simulation, the thickness direction retardation of the biaxial film 16b is set to 440 nm and the C plate 16a is not used in the first panel configuration. However, in the third panel configuration, the thickness direction of the biaxial film 16b is set. It was found that even when the phase difference was 440 nm and the C plate 16a was not used, almost the same result was obtained.

  Based on the knowledge obtained by the fifth simulation or the like, for example, the following liquid crystal display device can be used as the liquid crystal display device according to the fifth embodiment.

Similarly to the liquid crystal display device according to the first embodiment, the liquid crystal display device according to the fifth embodiment has the first panel configuration (see FIG. 1. However, in the liquid crystal display device according to the fifth embodiment, the C plate 16a is used. No.) is rotated in the clockwise direction by an angle θ not less than the lower limit θ _{l and not} more than the upper limit θ _u , for example. Both the lower limit value θ _l and the upper limit value θ _u are positive angles and satisfy θ _l <θ _u . Here, the units of θ, θ _l , and θ _u are all “°”.

  The liquid crystal display device according to the fifth embodiment differs from the liquid crystal display device according to the first embodiment in that the C plate 16a is not disposed.

Also, the lower limit value θ _l and the upper limit value θ _u are different from the liquid crystal display device according to the first embodiment in that they are expressed by the following equations (9) and (10).

  The other points are the same as those of the liquid crystal display device according to the first embodiment.

  The display area (display surface) of the liquid crystal display device according to the fifth embodiment also has, for example, an upward direction of 12:00, a downward direction of 6 o'clock, a right direction of 3 o'clock, and a left direction of 9 o'clock. The liquid crystal display device according to the fifth embodiment is also arranged, for example, on a console between a driver seat and a passenger seat in an automobile.

  Further, also in the liquid crystal display device according to the fifth embodiment, the central molecular orientation direction of the liquid crystal layer 13 is (270-θ) ° direction, and the clockwise direction from the right direction (3 o'clock direction) of the display region by (90 + θ) °. It is the direction rotated in the direction. The absorption axis orientation of the crossed Nicols polarizing plates 17 and 18 is an orientation that forms an angle of 45 ° with the central molecular orientation orientation of the liquid crystal layer 13. For example, the absorption axis orientation of the upper polarizing plate 17 is (135−θ) ° − (315 The −θ) ° azimuth and the lower polarizer 18 absorption axis azimuth are (45−θ) ° − (225−θ) ° azimuth.

  The liquid crystal display device according to the fifth embodiment is also a liquid crystal display device having good display quality. For example, light leakage of light on the short wavelength side is suppressed at 60 ° oblique observation at least in the left-right direction (3 o'clock to 9 o'clock direction) with Δnd equal to or higher than the retardation of the liquid crystal layer under conventional ideal conditions, and the background This is a liquid crystal display device in which the blueness of the display state is reduced. For example, a brown background color tone can be realized in the horizontal direction.

  The angle θ is preferably 25 ° or less. By setting θ to 25 ° or less, it is possible to suppress the appearance of asymmetry of the light transmittance in the horizontal direction during bright display.

  In the liquid crystal display device according to the fifth embodiment, the central molecular orientation of the liquid crystal layer 13 is set to a direction rotated clockwise by (90 + θ) ° from the right direction of the display area, but is not limited to the right direction of the display area. Alternatively, a direction rotated clockwise by (90 + θ) ° from the first direction for reducing the bluishness of the background color tone may be used.

Further, the liquid crystal display element (between the lower substrate 12 and the lower polarizing plate 18) of the first panel configuration (see FIG. 1; however, the C plate 16a is not used in the liquid crystal display device according to the fifth embodiment). In addition to the liquid crystal display device in which the biaxial film 16b is arranged in the clockwise direction by an angle θ not less than the lower limit θ _{l and not} more than the upper limit θ _u , a third panel configuration (FIG. 3) is used. in the reference), the liquid crystal display device using no C plate 16a (liquid crystal display element disposing a biaxial film 16b between the upper substrate 11 and the upper polarizing plate 17), for example, the lower limit value theta _l or more, more than the upper limit theta _u The liquid crystal display device can also be rotated clockwise by the angle θ.

  Further, the thickness direction retardation of the biaxial film 16b may be within a range of 440 nm ± 10 nm (430 nm to 450 nm). The same effect as the case where the thickness direction retardation of the biaxial film 16b is 440 nm will be exhibited.

[Sixth simulation]
In the first panel configuration, a sixth simulation will be described in which the biaxial film 16b has a thickness direction retardation of 220 nm and the C plate 16a has a thickness direction retardation of 220 nm.

  First, from a direction orthogonal to the central molecular alignment direction (6 o'clock direction) of the liquid crystal layer 13 and 45 ° with the absorption axis direction of the crossed Nicols polarizing plates 17 and 18, for example, from the polar angle 60 ° direction of the 3 o'clock direction When the viewing angle compensation condition (the conventional ideal condition) in which the background light transmittance is the lowest when observed is analyzed by simulation, the in-plane retardation Re = 50 nm of the biaxial film 16b and the retardation Δnd = 610 nm of the liquid crystal layer 13 are obtained. The value was obtained.

  Next, the in-plane retardation Re of the biaxial film 16b and the retardation Δnd of the liquid crystal layer 13 are variously changed, and the background light transmittance when tilted from the front to the polar angle 60 ° (from the polar angle 60 ° direction) The observation orientation dependency of the observed background light transmittance) was calculated. The observation azimuth is expressed as an angle formed with respect to the 3 o'clock (0 °) azimuth. When viewed from the upper polarizing plate 17 side (Z-axis positive direction), the observation direction is a positive angle when it is counterclockwise from the 3 o'clock direction, and is a negative angle when it is clockwise from the 3 o'clock direction.

  Further, from the calculation result of the dependency of the background light transmittance on the observation direction, an observation direction range in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal condition was calculated.

FIG. 21 shows the lower limit value θ _l and the upper limit value of the observation azimuth range (when observing in the 60 ° polar angle direction) in which the chromaticity is larger than the chromaticity during frontal observation under conventional ideal conditions under each Re and Δnd conditions. It is a table _| surface which shows (theta) _u .

In the table of FIG. 21, an asterisk (*) is added to the range of the lower limit value θ _l to the upper limit value θ _u in which the retardation Δnd of the liquid crystal layer 13 is smaller than the conventional ideal condition (610 nm). In addition, an asterisk (*) is attached to the observation azimuth range including 0 ° between the lower limit value θ _l and the upper limit value θ _u (excluding the range marked with *).

An asterisk (*) or a rice sign (*) is attached to the range of all lower limit values θ _l to upper limit value θ _u shown in the table.

  Therefore, in the panel configuration of the sixth simulation, FIG. 7B (first simulation), FIG. 11B (second simulation), FIG. 14B (third simulation), FIG. 17B (fourth simulation), and FIG. It can be seen that there is no range corresponding to the range shown in (Simulation).

  In the sixth simulation, the thickness direction retardation of the biaxial film 16b is 220 nm and the thickness direction retardation of the C plate 16a is 220 nm in the first panel configuration, but in the second panel configuration and the third panel configuration, It was found that substantially the same results were obtained when the thickness direction retardation of the biaxial film 16b was 220 nm and the thickness direction retardation of the C plate 16a was 220 nm.

[Method of Manufacturing Liquid Crystal Display Device According to Examples]
The vertical alignment type liquid crystal display device 20 (see FIG. 23) according to the embodiment can be manufactured as follows, for example.

  First, the vertical alignment type liquid crystal display element 10 (see FIG. 22) is manufactured.

  Two 0.7 mm-thick blue glass substrates (upper transparent substrate 11 a and lower transparent substrate) each patterned with an ITO film (upper transparent electrode 11 b and lower transparent electrode 12 b) by photolithography and etching. A substrate 12a) is prepared.

For example, an SiO ₂ film is formed as an upper insulating film 11c and a lower insulating film 12c so as to cover at least the area corresponding to the display area (effective display portion) of the electrodes 11b and 12b forming surfaces of the substrates 11a and 12a.

  Vertical alignment film material manufactured by Nissan Chemical Industries, Ltd., for example, on the insulating films 11c and 12c so as to cover at least the area corresponding to the display area (effective display portion) of the electrodes 11b and 12b forming surfaces of the substrates 11a and 12a. SE4811 is applied and baked at 180 ° C to 220 ° C.

  The surface of the vertical alignment film is rubbed to one position with a cotton rubbing cloth having a cloth thickness of about 2.8 mm to 3.2 mm. Depending on the rubbing conditions, the pretilt angle of the liquid crystal layer 13 of the liquid crystal display element 10 after completion is controlled within a range of, for example, 88.5 ° to 89.9 °. In this way, for example, the upper vertical alignment film 11d and the lower vertical alignment film 12d subjected to the alignment treatment are formed on the insulating films 11c and 12c.

  Through the above steps, the upper substrate 11 and the lower substrate 12 are manufactured.

  A sealing material 14 is printed in a frame shape so as to surround at least a region larger than the display region (effective display portion) on the surface on which the alignment films 11d and 12d of the one substrate 11 and 12 are formed. The sealing material 14 is a glass fiber spacer manufactured by Nippon Electric Glass Co., Ltd. having a diameter of 5 μm, and a gold-coated plastic ball manufactured by Sekisui Chemical Co., Ltd. that secures electrical connection between the substrates 11 and 12. 0.0 wt% is added.

On the surfaces of the other substrates 11 and 12 where the alignment films 11d and 12d are formed, plastic ball spacers 13s made of Sekisui Chemical Co., Ltd. having a diameter of 4.9 μm are sprayed at 400 pieces / mm ² by a dry spraying method.

  The substrates 11 and 12 are aligned and overlapped so that the alignment film 11d and 12d formation surfaces face each other, and the substrates 11 and 12 are baked (150 ° C.) in a pressed state, and the sealing material 14 is cured. Complete an empty cell.

  A liquid crystal material with negative dielectric anisotropy and refractive index anisotropy of 0.18 manufactured by Merck Co., Ltd. is injected into an empty cell by vacuum injection, and then the injection port is sealed with an ultraviolet curable resin. Then, heat treatment is performed at 120 ° C. for 1 hour to form the liquid crystal layer 13. The retardation Δnd of the liquid crystal layer 13 is about 900 nm.

  After the surfaces of the substrates 11 and 12 are washed with a neutral detergent, the upper polarizing plate 17 is bonded to the upper substrate 11 surface, and the C plate 16a, the biaxial film 16b, and the lower polarizing plate 18 are bonded to the lower substrate 12 surface side. As the polarizing plates 17 and 18, for example, a polarizing plate SHC13U manufactured by Polatechno Co., Ltd. is used. The C plate 16a is, for example, a biaxially stretched COP film having an in-plane retardation Re = 4 nm and a thickness direction retardation Rth = 220 nm, and the biaxial film 16b is, for example, an in-plane retardation Re = 44 nm, in the thickness direction. A biaxially stretched COP film having a phase difference Rth = 440 nm is used. The polarizing plates 17 and 18 are arranged in crossed Nicols so that the respective absorption axis directions form an angle of 45 ° with respect to the central molecular orientation direction of the liquid crystal layer 13 defined by the rubbing process.

  The rubbing treatment of the alignment films 11d and 12d is performed by 103 ° in the clockwise direction from the right direction (0 ° azimuth) of the display region, in which the central molecular alignment direction of the liquid crystal layer 13 is defined by, for example, the formation mode of the electrodes 11b and 12b. It is applied so as to be in the rotated direction (257 ° azimuth). Further, the upper polarizing plate 17 and the lower polarizing plate 18 are bonded so that, for example, the absorption axis directions are 122 ° -302 ° direction and 32 ° -212 ° direction, respectively.

  A lead frame, a flexible film via an anisotropic conductive film, and a driver IC are bonded to the external extraction electrode 15b.

  Through the above process, the vertical alignment type liquid crystal display element 10 is manufactured.

  For example, a drive circuit 21 that multiplex-drives the liquid crystal display element 10 is electrically connected to the vertical alignment type liquid crystal display element 10. Further, a backlight unit 22 including, for example, a white light source is disposed below the lower polarizing plate 18 of the vertical alignment type liquid crystal display element 10. The vertical alignment type liquid crystal display element 10, the drive circuit 21, and the backlight unit 22 are fixedly disposed in the housing 23.

  In this way, the vertical alignment type liquid crystal display device 20 is manufactured.

  It was confirmed that the color tone of the background observed from the direction of about 60 ° in the left-right polar angle of the liquid crystal display device 20 was more yellowish than that in frontal observation.

In the liquid crystal display device 20, when the rotation angle θ = 13 °, FIG. 7B shows an in-plane retardation Re = 45 nm of the biaxial film 16b and a retardation Δnd = 900 nm of the liquid crystal layer 13. The calculation results of the lower limit value θ _l = 5 ° and the upper limit value θ _u = 12 ° are described. However, in the actually produced liquid crystal display element 10, it has been confirmed that the distance between the substrates 11 and 12 has an in-plane variation of about 5 μm ± 0.2 μm. Therefore, in the liquid crystal display device 20, retardation is achieved. There is a margin of Δnd of about ± 36 nm. Therefore, for example, the rotation angle θ = 13 ° is not incompatible with the range shown in FIG. 7B. This corresponds to that when the thickness of the liquid crystal layer 13 is uniform, a margin of the thickness direction retardation Rth of the biaxial film can be expected to be about ± 36 nm. In an actual commercial product, the in-plane variation of Rth of the biaxial film (biaxially stretched COP film) having a thickness direction retardation Rth of 440 nm is within ± 10 nm, and within the range of variation within ± 10 nm, For example, the effect of reducing the blueness of the background color tone in the horizontal direction is exhibited.

  As mentioned above, although this invention was demonstrated along simulation and an Example, this invention is not restrict | limited to these.

  For example, in the embodiment, both the substrates 11 and 12 (alignment films 11d and 12d) are subjected to the alignment treatment, but at least one of the substrates 11 and 12 includes the alignment films 11d and 12d on the liquid crystal layer 13 side. May be provided on at least one side of the substrates 11 and 12 (alignment films 11d and 12d).

  It will be apparent to those skilled in the art that other various modifications, improvements, combinations, and the like can be made.

  It can be used for various liquid crystal display devices. For example, it can be used as a liquid crystal display device mounted on transportation equipment (cars, trains, airplanes, ships, etc.). Further, it can be used for industrial display devices, instruments, consumer electronic devices, and the like.

  According to the design method of the conventional liquid crystal display device, for example, a biaxial film having a thickness direction retardation Rth = 440 nm is used as a viewing angle compensation plate, and the background chromaticity viewed from an oblique direction is changed to the conventional ideal In order to make it larger than the chromaticity at the time of front observation under the conditions, for example, it was necessary to reduce the retardation Δnd of the liquid crystal layer. Although it is effective to reduce the in-plane retardation Re of the biaxial film, Re is uniquely determined in a commercial product and cannot be easily changed.

  The liquid crystal display device according to the embodiment can easily make the background chromaticity viewed from an oblique direction larger than the chromaticity at the time of frontal observation under conventional ideal conditions without impairing the steepness in the electro-optical characteristics, for example. It is.

  In the first to sixth simulations, an observation azimuth range in which the chromaticity is larger than the chromaticity during frontal observation under the conventional ideal condition was calculated. Here, in the vertical alignment type liquid crystal display element, the chromaticity at the time of front observation does not depend on the retardation Δnd of the liquid crystal layer, the in-plane retardation Re of the viewing angle compensation plate, and the retardation Rth in the thickness direction. . For this reason, the chromaticity (x, y) at the time of front observation of the liquid crystal display devices according to the first to fifth embodiments is the chromaticity at the time of front observation (x, y) = (0.31371, 0) in the conventional ideal condition. .318411). Therefore, the liquid crystal display device according to the embodiment is a liquid crystal display device in which the background chromaticity when observed from at least a 60 ° oblique direction in the left-right direction is larger than the background chromaticity during front observation.

10 Vertical alignment type liquid crystal display element 11 Upper substrate (common substrate)
11a Upper transparent substrate 11b Upper transparent electrode (common electrode)
11c Upper insulating film 11d Upper vertical alignment film 12 Lower substrate (segment substrate)
12a Lower transparent substrate 12b Lower transparent electrode (segment electrode)
12c Lower insulating film 12d Lower vertical alignment film 13 Vertical alignment liquid crystal layer 13s Spacer 14 Main seal portion 15 External extraction terminal portion 15b External extraction electrode 16 Viewing angle compensation plate 16a C plate 16b Biaxial film 17 Upper polarizing plate 17a Polarizing plate polarization Layer 17b Base film layer 18 Lower polarizing plate 18a Polarizing polarizing layer 18b Base film layer 20 Vertical alignment type liquid crystal display device 21 Drive circuit 22 Backlight unit 23 Housing 31 Driver seat 32 Passenger seat

Claims (15)

A first substrate comprising a first electrode;
A second substrate comprising a second electrode and disposed opposite to and substantially parallel to the first substrate;
A vertically aligned liquid crystal layer disposed between the first and second substrates;
A first polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the first substrate;
A second polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the second substrate in a crossed Nicol manner with the first polarizing plate;
A C plate having a thickness direction retardation of 210 nm to 230 nm and a biaxial film having a thickness direction retardation of 430 nm to 450 nm, disposed between the second substrate and the second polarizing plate;
A white light source disposed on the opposite side of the second polarizing plate from the second substrate;
The central molecular orientation of the vertically aligned liquid crystal layer forms an angle of 45 ° with the absorption axis orientation of the first and second polarizing plates, and is a direction rotated clockwise from the first direction by (90 + θ) ° And
The θ is an angle of θ ₁ or more and θ _u or less,
The θ _l and θ _u are positive angles that satisfy θ _l <θ _u , the retardation of the vertical alignment liquid crystal layer is Δnd, and the in-plane retardation of the biaxial film is Re,
A liquid crystal display device represented by A first substrate comprising a first electrode;
A second substrate comprising a second electrode and disposed opposite to and substantially parallel to the first substrate;
A vertically aligned liquid crystal layer disposed between the first and second substrates;
A first polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the first substrate;
A second polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the second substrate in a crossed Nicol manner with the first polarizing plate;
A C plate having a thickness direction retardation of 210 nm to 230 nm, disposed between the first substrate and the first polarizing plate;
A biaxial film having a thickness direction retardation of 430 nm to 450 nm, disposed between the second substrate and the second polarizing plate;
A white light source disposed on the opposite side of the second polarizing plate from the second substrate;
The central molecular orientation of the vertically aligned liquid crystal layer forms an angle of 45 ° with the absorption axis orientation of the first and second polarizing plates, and is a direction rotated clockwise from the first direction by (90 + θ) ° And
The θ is an angle of θ ₁ or more and θ _u or less,
The θ _l and θ _u are positive angles that satisfy θ _l <θ _u , the retardation of the vertical alignment liquid crystal layer is Δnd, and the in-plane retardation of the biaxial film is Re,
A liquid crystal display device represented by A first substrate comprising a first electrode;
A second substrate comprising a second electrode and disposed opposite to and substantially parallel to the first substrate;
A vertically aligned liquid crystal layer disposed between the first and second substrates;
A first polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the first substrate;
A second polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the second substrate in a crossed Nicol manner with the first polarizing plate;
A biaxial film having a thickness direction retardation of 430 nm to 450 nm, disposed between the first substrate and the first polarizing plate;
A C plate having a thickness direction retardation of 210 nm to 230 nm, disposed between the second substrate and the second polarizing plate;
A white light source disposed on the opposite side of the second polarizing plate from the second substrate;
The central molecular orientation of the vertically aligned liquid crystal layer forms an angle of 45 ° with the absorption axis orientation of the first and second polarizing plates, and is a direction rotated clockwise from the first direction by (90 + θ) ° And
The θ is an angle of θ ₁ or more and θ _u or less,
The θ _l and θ _u are positive angles that satisfy θ _l <θ _u , the retardation of the vertical alignment liquid crystal layer is Δnd, and the in-plane retardation of the biaxial film is Re,
A liquid crystal display device represented by A first substrate comprising a first electrode;
A second substrate comprising a second electrode and disposed opposite to and substantially parallel to the first substrate;
A vertically aligned liquid crystal layer disposed between the first and second substrates;
A first polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the first substrate;
A second polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the second substrate in a crossed Nicol manner with the first polarizing plate;
A C plate having a thickness direction retardation of 430 nm to 450 nm, and a biaxial film having a thickness direction retardation of 210 nm to 230 nm, disposed between the second substrate and the second polarizing plate;
A white light source disposed on the opposite side of the second polarizing plate from the second substrate;
The central molecular orientation of the vertically aligned liquid crystal layer forms an angle of 45 ° with the absorption axis orientation of the first and second polarizing plates, and is a direction rotated clockwise from the first direction by (90 + θ) ° And
The θ is an angle of θ ₁ or more and θ _u or less,
The θ _l and θ _u are positive angles that satisfy θ _l <θ _u , the retardation of the vertical alignment liquid crystal layer is Δnd, and the in-plane retardation of the biaxial film is Re,
A liquid crystal display device represented by A first substrate comprising a first electrode;
A second substrate comprising a second electrode and disposed opposite to and substantially parallel to the first substrate;
A vertically aligned liquid crystal layer disposed between the first and second substrates;
A first polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the first substrate;
A second polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the second substrate in a crossed Nicol manner with the first polarizing plate;
A C plate having a thickness direction retardation of 430 nm to 450 nm, disposed between the first substrate and the first polarizing plate;
A biaxial film having a thickness direction retardation of 210 nm to 230 nm, disposed between the second substrate and the second polarizing plate;
A white light source disposed on the opposite side of the second polarizing plate from the second substrate;
The central molecular orientation of the vertically aligned liquid crystal layer forms an angle of 45 ° with the absorption axis orientation of the first and second polarizing plates, and is a direction rotated clockwise from the first direction by (90 + θ) ° And
The θ is an angle of θ ₁ or more and θ _u or less,
The θ _l and θ _u are positive angles that satisfy θ _l <θ _u , the retardation of the vertical alignment liquid crystal layer is Δnd, and the in-plane retardation of the biaxial film is Re,
A liquid crystal display device represented by A first substrate comprising a first electrode;
A second substrate comprising a second electrode and disposed opposite to and substantially parallel to the first substrate;
A vertically aligned liquid crystal layer disposed between the first and second substrates;
A first polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the first substrate;
A second polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the second substrate in a crossed Nicol manner with the first polarizing plate;
A biaxial film having a thickness direction retardation of 210 nm to 230 nm, disposed between the first substrate and the first polarizing plate;
A C plate having a thickness direction retardation of 430 nm to 450 nm, disposed between the second substrate and the second polarizing plate;
A white light source disposed on the opposite side of the second polarizing plate from the second substrate;
The central molecular orientation of the vertically aligned liquid crystal layer forms an angle of 45 ° with the absorption axis orientation of the first and second polarizing plates, and is a direction rotated clockwise from the first direction by (90 + θ) ° And
The θ is an angle of θ ₁ or more and θ _u or less,
The θ _l and θ _u are positive angles that satisfy θ _l <θ _u , the retardation of the vertical alignment liquid crystal layer is Δnd, and the in-plane retardation of the biaxial film is Re,
A liquid crystal display device represented by A first substrate comprising a first electrode;
A second substrate comprising a second electrode and disposed opposite to and substantially parallel to the first substrate;
A vertically aligned liquid crystal layer disposed between the first and second substrates;
A first polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the first substrate;
A second polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the second substrate in a crossed Nicol manner with the first polarizing plate;
A C plate having a thickness direction retardation of 525 nm to 545 nm and a biaxial film having a thickness direction retardation of 115 nm to 135 nm, disposed between the second substrate and the second polarizing plate;
A white light source disposed on the opposite side of the second polarizing plate from the second substrate;
The central molecular orientation of the vertically aligned liquid crystal layer forms an angle of 45 ° with the absorption axis orientation of the first and second polarizing plates, and is a direction rotated clockwise from the first direction by (90 + θ) ° And
The θ is an angle of θ ₁ or more and θ _u or less,
The θ _l and θ _u are positive angles that satisfy θ _l <θ _u , the retardation of the vertical alignment liquid crystal layer is Δnd, and the in-plane retardation of the biaxial film is Re,
A liquid crystal display device represented by A first substrate comprising a first electrode;
A second substrate comprising a second electrode and disposed opposite to and substantially parallel to the first substrate;
A vertically aligned liquid crystal layer disposed between the first and second substrates;
A first polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the first substrate;
A second polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the second substrate in a crossed Nicol manner with the first polarizing plate;
A C plate having a thickness direction retardation of 525 nm to 545 nm, disposed between the first substrate and the first polarizing plate;
A biaxial film having a thickness direction retardation of 115 nm to 135 nm, disposed between the second substrate and the second polarizing plate;
A white light source disposed on the opposite side of the second polarizing plate from the second substrate;
The central molecular orientation of the vertically aligned liquid crystal layer forms an angle of 45 ° with the absorption axis orientation of the first and second polarizing plates, and is a direction rotated clockwise from the first direction by (90 + θ) ° And
The θ is an angle of θ ₁ or more and θ _u or less,
The θ _l and θ _u are positive angles that satisfy θ _l <θ _u , the retardation of the vertical alignment liquid crystal layer is Δnd, and the in-plane retardation of the biaxial film is Re,
A liquid crystal display device represented by A first substrate comprising a first electrode;
A second substrate comprising a second electrode and disposed opposite to and substantially parallel to the first substrate;
A vertically aligned liquid crystal layer disposed between the first and second substrates;
A first polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the first substrate;
A second polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the second substrate in a crossed Nicol manner with the first polarizing plate;
A biaxial film having a thickness direction retardation of 115 nm to 135 nm, disposed between the first substrate and the first polarizing plate;
A C plate having a thickness direction retardation of 525 nm to 545 nm, disposed between the second substrate and the second polarizing plate;
A white light source disposed on the opposite side of the second polarizing plate from the second substrate;
The central molecular orientation of the vertically aligned liquid crystal layer forms an angle of 45 ° with the absorption axis orientation of the first and second polarizing plates, and is a direction rotated clockwise from the first direction by (90 + θ) ° And
The θ is an angle of θ ₁ or more and θ _u or less,
The θ _l and θ _u are positive angles that satisfy θ _l <θ _u , the retardation of the vertical alignment liquid crystal layer is Δnd, and the in-plane retardation of the biaxial film is Re,
A liquid crystal display device represented by A first substrate comprising a first electrode;
A second substrate comprising a second electrode and disposed opposite to and substantially parallel to the first substrate;
A vertically aligned liquid crystal layer disposed between the first and second substrates;
A first polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the first substrate;
A second polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the second substrate in a crossed Nicol manner with the first polarizing plate;
A biaxial film having a thickness direction retardation of 650 nm to 670 nm, disposed between the second substrate and the second polarizing plate;
A white light source disposed on the opposite side of the second polarizing plate from the second substrate;
The central molecular orientation of the vertically aligned liquid crystal layer forms an angle of 45 ° with the absorption axis orientation of the first and second polarizing plates, and is a direction rotated clockwise from the first direction by (90 + θ) ° And
The θ is an angle of θ ₁ or more and θ _u or less,
The θ _l and θ _u are positive angles that satisfy θ _l <θ _u , the retardation of the vertical alignment liquid crystal layer is Δnd, and the in-plane retardation of the biaxial film is Re,
A liquid crystal display device represented by A first substrate comprising a first electrode;
A second substrate comprising a second electrode and disposed opposite to and substantially parallel to the first substrate;
A vertically aligned liquid crystal layer disposed between the first and second substrates;
A first polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the first substrate;
A second polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the second substrate in a crossed Nicol manner with the first polarizing plate;
A biaxial film having a thickness direction retardation of 650 nm to 670 nm, disposed between the first substrate and the first polarizing plate;
A white light source disposed on the opposite side of the second polarizing plate from the second substrate;
The central molecular orientation of the vertically aligned liquid crystal layer forms an angle of 45 ° with the absorption axis orientation of the first and second polarizing plates, and is a direction rotated clockwise from the first direction by (90 + θ) ° And
The θ is an angle of θ ₁ or more and θ _u or less,
The θ _l and θ _u are positive angles that satisfy θ _l <θ _u , the retardation of the vertical alignment liquid crystal layer is Δnd, and the in-plane retardation of the biaxial film is Re,
A liquid crystal display device represented by A first substrate comprising a first electrode;
A second substrate comprising a second electrode and disposed opposite to and substantially parallel to the first substrate;
A vertically aligned liquid crystal layer disposed between the first and second substrates;
A first polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the first substrate;
A second polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the second substrate in a crossed Nicol manner with the first polarizing plate;
A biaxial film having a thickness direction retardation of 430 nm to 450 nm, disposed between the second substrate and the second polarizing plate;
A white light source disposed on the opposite side of the second polarizing plate from the second substrate;
The central molecular orientation of the vertically aligned liquid crystal layer forms an angle of 45 ° with the absorption axis orientation of the first and second polarizing plates, and is a direction rotated clockwise from the first direction by (90 + θ) ° And
The θ is an angle of θ ₁ or more and θ _u or less,
The θ _l and θ _u are positive angles that satisfy θ _l <θ _u , the retardation of the vertical alignment liquid crystal layer is Δnd, and the in-plane retardation of the biaxial film is Re,
A liquid crystal display device represented by A first substrate comprising a first electrode;
A second substrate comprising a second electrode and disposed opposite to and substantially parallel to the first substrate;
A vertically aligned liquid crystal layer disposed between the first and second substrates;
A first polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the first substrate;
A second polarizing plate disposed on the opposite side of the vertical alignment liquid crystal layer of the second substrate in a crossed Nicol manner with the first polarizing plate;
A biaxial film having a thickness direction retardation of 430 nm to 450 nm, disposed between the first substrate and the first polarizing plate;
A white light source disposed on the opposite side of the second polarizing plate from the second substrate;
The central molecular orientation of the vertically aligned liquid crystal layer forms an angle of 45 ° with the absorption axis orientation of the first and second polarizing plates, and is a direction rotated clockwise from the first direction by (90 + θ) ° And
The θ is an angle of θ ₁ or more and θ _u or less,
The θ _l and θ _u are positive angles that satisfy θ _l <θ _u , the retardation of the vertical alignment liquid crystal layer is Δnd, and the in-plane retardation of the biaxial film is Re,
A liquid crystal display device represented by   The liquid crystal display device according to claim 1, wherein the first direction is a right direction of a display area.   The liquid crystal display device according to claim 1, wherein θ is an angle of 25 ° or less.