Liquid crystal display device

Abstract

The present invention provides a liquid crystal display device with excellent display quality and suppressed generation of halation. The liquid crystal display device of the present invention sequentially includes: a first polarizer; a liquid crystal cell; a second polarizer; and a direct-lit backlight using point light sources. Among them, a light control member is further provided between the second polarizer and the direct-lit backlight, and the relationships of the following formulas (1) to (3) are satisfied. Formula (1): 70% ≤ (I20 / I0) × 100 ≤ 90%; Formula (2): 10% ≤ (I40 / I0) × 100 ≤ 35%; Formula (3): 1% ≤ (I60 / I0) × 100 ≤ 20%.

Description

Technical Field

[0001] The present invention relates to a liquid crystal display device. Background Art

[0002] A liquid crystal display device is an electronic device that uses the fact that the transmittance of liquid crystal changes with applied voltage to convert electrical information into visual information for display.

[0003] A backlight unit is used in a liquid crystal display device. For example, in Patent Document 1, a direct-type backlight that is arranged directly below a liquid crystal display panel is used.

[0004] Previous technical literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2007-123250 Summary of the Invention

[0007] Technical issues to be solved by the invention

[0008] The present inventors studied the characteristics of a liquid crystal display device with a direct backlight as described in Patent Document 1 and found that in areas with a large difference in brightness, haloing occurs where light spreads even in areas that are originally displayed black, blurring the outline of the bright area.

[0009] Furthermore, liquid crystal display devices are also required to have excellent display quality.

[0010] In view of the above-mentioned circumstances, an object of the present invention is to provide a liquid crystal display device having excellent display quality and suppressed halation.

[0011] Means for solving technical problems

[0012] The present inventors have conducted intensive studies on the problems of the conventional technology and have found that the above-mentioned problems can be solved by the following configuration.

[0013] (1) A liquid crystal display device comprising:

[0014] 1st polarizer;

[0015] Liquid crystal cell;

[0016] a second polarizer; and

[0017] Direct backlight, using point light source,

[0018] in,

[0019] There is also a light control component between the second polarizer and the direct-type backlight.

[0020] Satisfies the relationships of the following formulas (1) to (3).

[0021] (2) The liquid crystal display device according to (1), wherein

[0022] The light control member has a first optically anisotropic layer that satisfies the relationships of the following formulas (4) to (6).

[0023] (3) The liquid crystal display device according to (1) or (2), wherein

[0024] The light control member has a light absorption anisotropic layer containing a dichroic substance,

[0025] When the direction with the highest transmittance with respect to the surface of the light absorption anisotropic layer is set as the transmission axis, the angle formed by the normal direction of the light absorption anisotropic layer and the transmission axis is 0 to 45°.

[0026] (4) The liquid crystal display device according to any one of (1) to (3), wherein

[0027] The light control member has a louver layer in which light-transmitting bands and light-shielding bands are alternately and repeatedly arranged.

[0028] (5) The liquid crystal display device according to any one of (1) to (4), wherein

[0029] In at least one of between the first polarizer and the liquid crystal cell and between the second polarizer and the liquid crystal cell, there is a second optically anisotropic layer including a positive A plate that satisfies the relationships of the following formulas (7) to (8) and a positive C plate that satisfies the relationships of the following formulas (9) to (10).

[0030] (6) The liquid crystal display device according to any one of (1) to (5), wherein

[0031] In at least one of between the first polarizer and the liquid crystal cell and between the second polarizer and the liquid crystal cell, there is a third optically anisotropic layer that satisfies the relationships of the following formulas (11) to (12).

[0032] Advantages of the Invention

[0033] [[ID=(39)]]According to the present invention, it is possible to provide a liquid crystal display device with excellent display quality and suppressed halation generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic diagram showing an example of the liquid crystal display device of the present invention.

[0035] Figure 2 [[ID=(49)]]is a diagram for explaining the definitions of the polar angle and the azimuth angle.

[0036] Figure 3It is a cross-sectional view showing an example of a direct-lit backlight.

[0037] Figure 4 It is a plan view showing an example of a direct-lit backlight.

[0038] Figure 5 It is a schematic view showing an example of a louver layer.

[0039] Figure 6 It is along Figure 5 The cross-sectional view taken along line II-II in

[0040] Figure 7 It is a schematic view of an image displayed with halo evaluation. Detailed implementation mode

[0041] Hereinafter, the present invention will be described in detail. In addition, the numerical range indicated by "~" in this specification means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value. First, the terms used in this specification will be described.

[0042] Unless otherwise specified, the slow axis is defined at a wavelength of 550 nm.

[0043] In the present invention, Re(λ) and Rth(λ) respectively represent the in-plane retardation and the thickness-direction retardation at wavelength λ. When not particularly described, the wavelength λ is set to 550 nm.

[0044] In the present invention, Re(λ) and Rth(λ) are values measured at wavelength λ in AxoScan (manufactured by Axometrics, Inc.). By inputting the average refractive index ((nx + ny + nz) / 3) and the film thickness (d (μm)) in AxoScan, they are calculated

[0045] Slow axis direction (°)

[0046] Re(λ) = R0(λ)

[0047] Rth(λ) = ((nx + ny) / 2 - nz) × d.

[0048] In addition, R0(λ) is displayed as a value calculated by AxoScan, but means Re(λ).

[0049] In this specification, regarding the refractive indices nx, ny, and nz, an Abbe refractometer (NAR-4T, manufactured by ATAGO CO., LTD.) is used, and a sodium lamp (λ = 589 nm) is used as the light source for measurement. And when measuring the wavelength dependence, a multi-wavelength Abbe refractometer DR-M2 (manufactured by ATAGO CO., LTD.) can be used and measured in combination with an interference filter.

[0050] Moreover, the values in the Polymer Handbook (JOHN WILEY & SONS, INC) and the catalog values of various optical films can be used. The values of the average refractive index of the main optical films are exemplified below: cellulose acylate (1.48); cycloolefin polymer (1.52); polycarbonate (1.59); polymethyl methacrylate (1.49); and polystyrene (1.59).

[0051] Moreover, in this specification, the Nz coefficient refers to the value given by Nz = (nx - nz) / (nx - ny).

[0052] In this specification, "visible light" refers to light with a wavelength of 400 to 700 nm.

[0053] Moreover, in this specification, when there is no specific note regarding the measurement wavelength, the measurement wavelength is 550 nm.

[0054] In this specification, the positive A plate is defined as follows. When the refractive index in the in-plane slow axis direction (the direction in which the refractive index in the plane is the largest) of the thin film is nx, the refractive index in the direction orthogonal to the in-plane slow axis in the plane is ny, and the refractive index in the thickness direction is nz, the positive A plate satisfies the relationship of the following formula (X). In addition, in the positive A plate, Rth represents a positive value.

[0055] Formula (X): nx > ny ≒ nz

[0056] In addition, the above "≒" includes not only the case where the two are exactly the same, but also the case where the two are substantially the same. "Substantially the same" means that, for example, (ny - nz) × d (where d is the thickness of the thin film) being -10 to 10 nm, preferably -5 to 5 nm, is also included in "ny ≒ nz".

[0057] Moreover, in this specification, the positive C plate is defined as follows. When the refractive index in the in-plane slow axis direction (the direction in which the refractive index in the plane is the largest) of the thin film is nx, the refractive index in the direction orthogonal to the in-plane slow axis in the plane is ny, and the refractive index in the thickness direction is nz, the positive C plate satisfies the relationship of the following formula (Y). In addition, in the positive C plate, Rth represents a negative value.

[0058] Formula (Y): nx ≒ ny < nz

[0059] In addition, the above "≒" includes not only the case where the two are exactly the same, but also the case where the two are substantially the same. "Substantially the same" means that, for example, (nx - ny) × d (where d is the thickness of the thin film) being -10 to 10 nm, preferably -5 to 5 nm, is also included in "nx ≒ ny".

[0060] As a characteristic point of the liquid crystal display device of the present invention, the following can be cited: The light control member is arranged at a specified position to adjust the brightness ratio represented by I20 / I0, I40 / I0, and I60 / I0 described later. That is, in the present invention, by controlling the distribution of transmitted light of the liquid crystal display device, the desired effect is obtained.

[0061] Hereinafter, an example of the liquid crystal display device of the present invention will be described with reference to the accompanying drawings.

[0062] Figure 1 The liquid crystal display device 10 shown has, in order, a first polarizer 12, a liquid crystal cell 14 (the upper substrate 22 of the liquid crystal cell, a liquid crystal layer 26, and the lower substrate 24 of the liquid crystal cell), a second polarizer 16, a light control member 18, and a direct-lit backlight 20 using a point light source. The liquid crystal cell 14 includes an upper substrate 22, a lower substrate 24, and a liquid crystal layer 26 sandwiched therebetween.

[0063] Hereinafter, first, the relationships of formulas (1) to (3) that are characteristic points of the liquid crystal display device will be described, and then the components constituting the liquid crystal display device 10 will be described in detail.

[0064] In the liquid crystal display device of the present invention, the transmitted light under white display satisfies the relationships of the following formulas (1) to (3).

[0065] Formula (1) 70% ≤ (I20 / I0) × 100 ≤ 90%

[0066] Formula (2) 10% ≤ (I40 / I0) × 100 ≤ 35%

[0067] Formula (3) 1% ≤ (I60 / I0) × 100 ≤ 20%

[0068] I0 represents the brightness measured at a polar angle of 0° and an azimuth angle of 0° with the liquid crystal display device set to white display.

[0069] I20 represents the average brightness obtained by arithmetically averaging the brightnesses measured at a polar angle of 20° and an azimuth angle of 45°, a polar angle of 20° and an azimuth angle of 135°, a polar angle of 20° and an azimuth angle of 225°, and a polar angle of 20° and an azimuth angle of 315° with the liquid crystal display device set to white display.

[0070] I40 represents the average brightness obtained by arithmetically averaging the brightnesses measured at a polar angle of 40° and an azimuth angle of 45°, a polar angle of 40° and an azimuth angle of 135°, a polar angle of 40° and an azimuth angle of 225°, and a polar angle of 40° and an azimuth angle of 315° with the liquid crystal display device set to white display.

[0071] I60 represents the average luminance obtained by arithmetically averaging the luminance measured at a polar angle of 60° and an azimuth angle of 45°, the luminance measured at a polar angle of 60° and an azimuth angle of 135°, the luminance measured at a polar angle of 60° and an azimuth angle of 225°, and the luminance measured at a polar angle of 60° and an azimuth angle of 315° when the liquid crystal display device is set to white display.

[0072] "(I20 / I0)×100" in Equation (1) represents the ratio of I20 to I0, "(I40 / I0)×100" in Equation (2) represents the ratio of I40 to I0, and "(I60 / I0)×100" in Equation (3) represents the ratio of I60 to I0.

[0073] I20, I40, and I60 represent the average values of the luminance when the liquid crystal display device is set to white display and observed from a specified tilt direction. When these average luminances are within a specified range with respect to I0, which is the luminance in the front direction, the desired effect is obtained.

[0074] Hereinafter, first, based on Figure 2 , the above-mentioned polar angle and azimuth angle will be described. Figure 2 is equivalent to a diagram showing only the first polarizer 12 of the liquid crystal display device 10 in Figure 1 .

[0075] Figure 2 In, the plane of the first polarizer 12 (the main plane, the plane perpendicular to the thickness direction) is set as the xy plane, and the y-axis direction is set as the absorption axis of the first polarizer 12. Therefore, Figure 2 in, the y-axis direction becomes the reference for the azimuth angle of 0°. As shown in Figure 2 , the angle θ formed by the vector v1 and the z-axis is defined as the polar angle (the angle formed with the normal direction of the first polarizer 12), and the angle φ formed by the projection of the vector v1 onto the xy plane and the y-axis (the absorption axis of the first polarizer 12) is defined as the azimuth angle. That is, the polar angle is the angle formed with the normal direction of the first polarizer. And the azimuth angle is the angle formed with the absorption axis of the first polarizer.

[0076] For example, a polar angle of 20° means <9111111> the angle where θ is 20° in. And an azimuth angle of 45° means Figure 2 the angle where φ is 45° in.

[0077] In addition, in the present invention, when representing the azimuth angle, the first polarizer in the liquid crystal display device is observed from the visual recognition side, and the counterclockwise direction is represented by a positive value based on the absorption axis direction of the first polarizer. Therefore, Figure 2 in, when the azimuth angle is 45°, it means an azimuth that rotates 45° counterclockwise from the reference y-axis.

[0078] The liquid crystal display device of the present invention preferably satisfies the relationship of formula (1A) and more preferably satisfies the relationship of formula (1B) in terms of achieving at least one of the effects of further suppressing the halo effect and having more excellent display quality (hereinafter, simply referred to as "the point where the effect of the present invention is more excellent").

[0079] Formula (1A) 73% ≤ (I20 / I0) × 100 ≤ 87%

[0080] Formula (1B) 76% ≤ (I20 / I0) × 100 ≤ 84%

[0081] Moreover, the liquid crystal display device of the present invention preferably satisfies the relationship of formula (2A) and more preferably satisfies the relationship of formula (2B).

[0082] Formula (2A) 13% ≤ (I40 / I0) × 100 ≤ 30%

[0083] Formula (2B) 16% ≤ (I40 / I0) × 100 ≤ 19%

[0084] Moreover, the liquid crystal display device of the present invention preferably satisfies the relationship of formula (3A) and more preferably satisfies the relationship of formula (3B).

[0085] Formula (3A) 1% ≤ (I60 / I0) × 100 ≤ 15%

[0086] Formula (3B) 2% ≤ (I60 / I0) × 100 ≤ 5%

[0087] The above I0, I20, I40, and I60 are obtained by making the liquid crystal display device display white in a dark room and measuring the white brightness at a specified polar angle position and azimuth angle position using a measuring machine (EZ-Contrast XL88, manufactured by ELDIM Company).

[0088] More specifically, in a dark room, the liquid crystal display device is set to white display, and the measuring machine is placed at a position where the polar angle is 0° ( Figure 2 where θ in Figure 2 is 0°) and the azimuth angle is 0° (

[0089] where φ in Figure 2 is 20°) and the azimuth angle is 45° ( Figure 2 where φ in Figure 2 is 20°) and the azimuth angle is 135° ( Figure 2The brightness (brightness 20B) is obtained by arranging a measuring machine at a position where φ in it is 135°), and at a polar angle of 20° ( Figure 2 where θ in it is 20°) and an azimuth angle of 225° ( Figure 2 where φ in it is 225°), and the brightness (brightness 20C) is obtained by arranging a measuring machine at this position, and at a polar angle of 20° ( Figure 2 where θ in it is 20°) and an azimuth angle of 315° ( Figure 2 where φ in it is 315°), and the brightness (brightness 20D) is obtained by arranging a measuring machine at this position. Then, the arithmetic mean of the obtained 4 brightness values (brightness 20A, brightness 20B, brightness 20C, brightness 20D) is calculated to obtain the average brightness, which is designated as I20.

[0090] Furthermore, regarding I40, first, the liquid crystal display device is set to white display in a dark room, and the brightness (brightness 40A) is obtained by arranging a measuring machine at a position where the polar angle is 40° ( Figure 2 where θ in it is 40°) and the azimuth angle is 45° ( Figure 2 where φ in it is 45°), and the brightness (brightness 40B) is obtained by arranging a measuring machine at a position where the polar angle is 40° ( Figure 2 where θ in it is 40°) and the azimuth angle is 135° ( Figure 2 where φ in it is 135°), and the brightness (brightness 40C) is obtained by arranging a measuring machine at a position where the polar angle is 40° ( Figure 2 where θ in it is 40°) and the azimuth angle is 225° ( Figure 2 where φ in it is 225°), and the brightness (brightness 40D) is obtained by arranging a measuring machine at a position where the polar angle is 40° ( Figure 2 where θ in it is 40°) and the azimuth angle is 315° ( Figure 2 where φ in it is 315°). Then, the arithmetic mean of the obtained 4 brightness values (brightness 40A, brightness 40B, brightness 40C, brightness 40D) is calculated to obtain the average brightness, which is designated as I40.

[0091] Furthermore, regarding I60, first, the liquid crystal display device is set to white display in a dark room, and the brightness (brightness 60A) is obtained by arranging a measuring machine at a position where the polar angle is 60° ( Figure 2 where θ in it is 60°) and the azimuth angle is 45° ( Figure 2 where φ in it is 45°), and the brightness (brightness 60B) is obtained by arranging a measuring machine at a position where the polar angle is 60° ( Figure 2 where θ in it is 60°) and the azimuth angle is 135° ( Figure 2 where φ in it is 135°), and the brightness (brightness 60C) is obtained by arranging a measuring machine at a position where the polar angle is 60° ( Figure 2 where θ in it is 60°) and the azimuth angle is 225° ( Figure 2 where φ in it is 225°), and the brightness (brightness 60D) is obtained by arranging a measuring machine at a position where the polar angle is 60° ( Figure 2where θ is 60°) and azimuth angle 315°( Figure 2 The brightness (brightness 60D) is obtained by arranging a measuring machine at a position where φ in Figure 2 is 315°). Next, the arithmetic mean of the four obtained brightnesses (brightness 60A, brightness 60B, brightness 60C, brightness 60D) is calculated to obtain the average brightness, which is designated as I60.

[0092] <First polarizer and second polarizer>

[0093] There are no particular limitations on the types of the first polarizer and the second polarizer, and known polarizers can be cited.

[0094] As the first polarizer and the second polarizer, for example, linear polarizers are preferred. As the linear polarizer, a polarizer composed of an adhesive and iodine or a dichroic substance or a coating type polarizer is preferred.

[0095] Iodine and dichroic substances in the linear polarizer exhibit polarization performance by orienting in the adhesive. Iodine and dichroic substances are preferably oriented along the adhesive molecules, or the dichroic substance is oriented in one direction by self-assembly such as liquid crystal. Currently, commercially available polarizers are generally manufactured by immersing an extended polymer in a solution of iodine or a dichroic substance in a bath and allowing iodine or the dichroic substance to penetrate into the adhesive.

[0096] There are no particular limitations on the thicknesses of the first polarizer and the second polarizer, but from the viewpoint of thinning the liquid crystal display device, those of 30 μm or less are preferred, those of 15 μm or less are more preferred, and those of 10 μm or less are further preferred. In particular, during the use and durability test of the liquid crystal display device, from the viewpoint of suppressing appearance defects such as cracks and fractures in the polarizer due to differences in dimensional changes between components, the thicknesses of the first polarizer and the second polarizer are preferably 10 μm or less, more preferably 7 μm or less, and further preferably 3 μm or less.

[0097] There are no particular limitations on the lower limits of the thicknesses of the first polarizer and the second polarizer, but from the viewpoint of mechanical strength, those of 2 μm or more are preferred.

[0098] <Liquid crystal cell>

[0099] As the liquid crystal cell, liquid crystal cells capable of using various display modes can be used. For example, TN (Twisted Nematic), IPS (In-Plane Switching), FFS (Fringe Field Switching), FLC (Ferroelectric Liquid Crystal), AFLC (Anti-ferroelectric Liquid Crystal), OCB (Optically Compensatory Bend), STN (Super Twisted Nematic), VA (Vertically Aligned), and HAN (Hybrid Aligned Nematic) can be mentioned.

[0100] The structure of the liquid crystal cell is not particularly limited, but it is preferably in a form having a liquid crystal layer, an upper substrate and a lower substrate arranged so as to sandwich the liquid crystal layer. The types of the upper substrate and the lower substrate are not particularly limited, and for example, a glass substrate and a resin substrate can be mentioned.

[0101] It is preferable that an electrode (preferably a transparent electrode) is arranged on the surface of at least one of the upper substrate and the lower substrate.

[0102] A color filter layer and a TFT (Thin Film Transistor) layer can be included in the liquid crystal cell. The positions of the color filter layer and the TFT layer are not particularly limited, and generally, they are arranged on either surface of the upper substrate or the lower substrate. The color filter layer and the TFT layer are preferably arranged between the upper substrate and the lower substrate.

[0103] It is preferably arranged such that the slow axis (slow axis during black display) of the liquid crystalline compound in the liquid crystal layer is parallel to the absorption axis of the second polarizer.

[0104] Moreover, the liquid crystal cell preferably has pixels composed of at least sub-pixels of blue, green, and red.

[0105] <Direct-lit backlight>

[0106] The liquid crystal display device of the present invention has a direct-lit backlight using point light sources. The direct-lit backlight is a backlight having point light sources on the side opposite to the visual recognition side of the liquid crystal cell.

[0107] The structure of the above-mentioned direct-lit backlight is not particularly limited, and known direct-lit backlights can be mentioned.

[0108] Figure 3 and Figure 4 An example of a direct - type backlight is shown. Figure 3 A cross - sectional view showing the direct - type backlight, Figure 4 A plan view showing the direct - type backlight.

[0109] As Figure 3 and Figure 4 shown, the direct - type backlight 30 has a substrate 32 and a plurality of point light sources 34 two - dimensionally arranged on the substrate 32. The plurality of point light sources 34 can be driven by a local dimming method. The minimum unit of local dimming driving can be one point light source or two or more point light sources.

[0110] There is no particular limitation on the type of the point light source. For example, an LED (light emitting diode) and a laser light source can be cited.

[0111] The point light source can be a white light source, or a plurality of light sources with different emission colors can be used.

[0112] As the point light source, preferably Figure 3 a mini - LED in which the size S in

[0113] is 1.0 mm or less (preferably 0.6 mm or less, more preferably 0.15 mm or less). The arrangement of the point light sources is preferably a grid - like arrangement in a two - dimensional grid pattern, but can also be a triangular arrangement, a hexagonal arrangement, etc. In addition, the "grid - like arrangement in a two - dimensional grid pattern" here means that a light source row in which a plurality of point light sources are arranged at a constant pitch in one direction has a plurality of rows arranged in a direction intersecting with the one direction, and the point light sources are located at the grid points of the two - dimensional grid. When the above - mentioned one direction is orthogonal to the intersecting direction and the pitch of the point light sources on the light source row is the same as the arrangement pitch of the light source rows, the grid is square. When the pitch of the point light sources on the light source row is different from the arrangement pitch of the light source rows, the grid is rectangular. And when the above - mentioned one direction and the intersecting direction are not orthogonal, the grid is a parallelogram. Thus, the point light sources are preferably arranged regularly, but can also be arranged irregularly.

[0114] In addition, the interval P between the nearest point light sources is preferably 2 - 20 mm. In the case of regular arrangement, the interval between the point light sources means the arrangement pitch.

[0115] There is no particular limitation on the type of the substrate on which the point light sources are arranged, but a reflector is preferred.

[0116] As the reflector, for example, a reflector having a reflecting surface composed of a white PET (polyethylene terephthalate) and a multilayer film made of a polyester - based resin can be cited.

[0117] <Light control component>

[0118] The light control component included in the liquid crystal display device of the present invention is not particularly limited as long as it satisfies the necessary conditions of the above formulas (1) to (3), but the following modes 1 to 3 are preferred.

[0119] Mode 1: A first optically anisotropic layer that satisfies the relationships of the following formulas (4) to (6)

[0120] Mode 2: A light absorption anisotropic layer that contains a dichroic substance. When the direction with the highest transmittance with respect to the surface of the light absorption anisotropic layer is set as the transmission axis, the angle formed by the normal direction of the light absorption anisotropic layer and the transmission axis is 0 to 45°.

[0121] Mode 3: A louver layer in which light-transmitting bands and light-blocking bands are alternately and repeatedly arranged

[0122] Hereinafter, modes 1 to 3 will be described in detail.

[0123] (Mode 1)

[0124] As the light control component, a first optically anisotropic layer that satisfies the relationships of formulas (4) to (6) can be cited.

[0125] Formula (4) 0 nm ≤ Re1(550) ≤ 300 nm

[0126] Formula (5) 100 nm ≤ |Rth1(550)| ≤ 1000 nm

[0127] Formula (6) |Nz| ≥ 1.2

[0128] Re1(550) represents the in-plane retardation of the first optically anisotropic layer at a wavelength of 550 nm. Rth1(550) represents the retardation in the thickness direction of the first optically anisotropic layer at a wavelength of 550 nm. Nz represents the Nz coefficient of the first optically anisotropic layer. In formula (5), |Rth1(550)| represents the absolute value of Rth1(550). In formula (6), |Nz| represents the absolute value of the Nz coefficient.

[0129] Among them, in terms of more excellent effects of the present invention, the first optically anisotropic layer preferably satisfies the relationships of formulas (4A) to (6A).

[0130] Formula (4A) 100 nm ≤ Re1(550) ≤ 300 nm

[0131] Formula (5A) 200 nm ≤ |Rth1(550)| ≤ 600 nm

[0132] Formula (6A) 2.0 ≤ |Nz| ≤ 8.0

[0133] As long as the first optical anisotropic layer satisfies the above optical properties, its structure is not particularly limited. For example, a polymer film (especially a stretched polymer film) and a film formed using a liquid crystalline compound can be mentioned.

[0134] (Mode 2)

[0135] As a light control component, a light absorption anisotropic layer containing a dichroic substance can be mentioned. Among them, when the direction with the highest transmittance with respect to the surface of the light absorption anisotropic layer is set as the transmission axis, the angle formed by the normal direction of the light absorption anisotropic layer and the transmission axis is 0 to 45°.

[0136] Regarding the angle formed by the normal direction of the light absorption anisotropic layer and the transmission axis, in terms of more excellent effects of the present invention, the above angle is more preferably 0 to 20°, and further preferably 0 to 10°.

[0137] As a method for measuring the above transmission axis, in AxoScan OPMF-1 (manufactured by Opto Science, Inc.), the Mueller matrix of the light absorption anisotropic layer at a measurement wavelength of 550 nm is measured. During the measurement, the polar angle with respect to the normal direction of the light absorption anisotropic layer is changed at intervals of 5° from 0 to 90°, and the transmittance at the azimuth angle of each polar angle is measured, and the direction with the maximum transmittance is set as the transmission axis.

[0138] In order for the light absorption anisotropic layer to achieve the above-described orientation of the transmission axis, it is preferably adjusted so that the angle formed by the long axis of the dichroic substance and the thickness direction of the light absorption anisotropic layer is 0 to 45° (preferably 0 to 20°).

[0139] Among them, it is preferable to vertically align the dichroic substance in the light absorption anisotropic layer. In other words, it is preferable to align the dichroic substance so that the long axis direction of the dichroic substance is substantially parallel to the thickness direction of the anisotropic light absorption layer. "Substantially parallel" means that the angle formed by the long axis direction of the dichroic substance and the thickness direction of the anisotropic light absorption layer is 0 to 45°.

[0140] The degree of orientation of the light absorption anisotropic layer at a wavelength of 550 nm is not particularly limited, but in terms of more excellent effects of the present invention, it is preferably 0.80 or more, more preferably 0.90 or more, and further preferably 0.95 or more. As an upper limit, 1.00 can be mentioned.

[0141] The above degree of orientation is calculated by the following method.

[0142] First, in AxoScan OPMF-1 (manufactured by Opto Science, Inc.), the Mueller matrix of the photoabsorption anisotropic layer at a wavelength of 550 nm is measured at intervals of 5° within the polar angle range from -70° to 70°. Then, after removing the influence of surface reflection, ko[λ] and ke[λ] are calculated by fitting the following theoretical formula that takes into account Snell's law or Fresnel's law.

[0143] k = -log(T) × λ / (4πd)

[0144] The absorbance and dichroic ratio in the in-plane direction and thickness direction are calculated from the obtained ko[λ] and ke[λ], and finally the degree of orientation is determined.

[0145] The transmittance of the photoabsorption anisotropic layer at a wavelength of 550 nm in the front direction is preferably 70% or more, more preferably 80% or more. There is no particular limitation on the upper limit, but it is often 90% or less.

[0146] The transmittance of the photoabsorption anisotropic layer at a wavelength of 550 nm in the direction inclined 30° from the transmission axis is preferably 60% or less, more preferably 40% or less, and further preferably 30% or less.

[0147] The transmittance of the above-mentioned photoabsorption anisotropic layer can be appropriately adjusted by the concentration of the dichroic substance, the thickness of the photoabsorption anisotropic layer, etc.

[0148] The photoabsorption anisotropic layer is preferably formed using a composition containing a dichroic substance and a liquid crystalline compound.

[0149] A dichroic substance refers to a substance having the property that the absorbance in the long axis direction of the molecule is different from the absorbance in the short axis direction.

[0150] In addition, examples of the dichroic substance include rod-shaped dichroic substances and disc-shaped dichroic substances based on their molecular shapes, and rod-shaped dichroic substances are preferred.

[0151] The maximum absorption wavelength of the dichroic substance is preferably 400 - 500 nm, more preferably 440 - 480 nm.

[0152] As a method for measuring the maximum absorption wavelength of the dichroic substance, a chloroform solution containing the dichroic substance (concentration: 10 mg / L) and a reference solution not containing the dichroic substance are prepared, and the absorption spectrum of the dichroic substance is measured using a spectrophotometer (UV-3150 manufactured by SHIMADZU CORPORATION) (mode: double-beam method, wavelength range: 380 - 680 nm at a step of 2 nm), thereby obtaining the maximum absorption wavelength of the dichroic substance.

[0153] Examples of the dichroic substance include acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes, and anthraquinone dyes, with azo dyes being preferred. Examples of the azo dye include monoazo dyes, bisazo dyes, trisazo dyes, tetrakisazo dyes, and stilbene azo dyes, with bisazo dyes or trisazo dyes being preferred. Further, compounds described in JP-A-2018-053167 are also preferred.

[0154] The dichroic substance may have a polymerizable group. By having a polymerizable group in the dichroic substance, even when the amount of the dichroic substance used is large, the degree of crosslinking of the anisotropic light absorption layer will not decrease, and even if it is thin, it exhibits high selective wavelength absorbency, and an anisotropic light absorption layer excellent in durability can be formed.

[0155] Examples of the polymerizable group include polymerizable groups having an ethylenic unsaturated bond such as vinyl, vinyloxy, styryl, p-(2-phenylethenyl)phenyl, acryloyl, methacryloyl, acryloyloxy, and methacryloyloxy, epoxy groups, and oxetanyl groups.

[0156] The dichroic substance preferably has an aromatic ring. Examples of the aromatic ring include aromatic hydrocarbon rings and aromatic heterocyclic rings, among which aromatic hydrocarbon rings are preferred, and benzene rings are more preferred.

[0157] The liquid crystalline compound preferably has a polymerizable group. That is, the composition preferably contains a polymerizable liquid crystalline compound (a liquid crystalline compound having a polymerizable group). The definition of the polymerizable group is as described in the section on the dichroic substance.

[0158] The liquid crystalline compound preferably has an aromatic ring. Examples of the aromatic ring include aromatic hydrocarbon rings and aromatic heterocyclic rings, among which aromatic hydrocarbon rings are preferred, and benzene rings are more preferred.

[0159] Examples of the polymerizable liquid crystalline compound include a low-molecular-weight liquid crystalline compound having a polymerizable group and a high-molecular-weight liquid crystalline compound having a polymerizable group.

[0160] Here, the "low-molecular-weight liquid crystalline compound" refers to a liquid crystalline compound that does not have a repeating unit in its chemical structure. And the "high-molecular-weight liquid crystalline compound" refers to a liquid crystalline compound that has a repeating unit in its chemical structure.

[0161] Examples of the low-molecular-weight liquid crystalline compound include compounds described in JP-A-2013-228706.

[0162] Examples of the high-molecular-weight liquid crystalline compound include a thermotropic liquid crystalline polymer described in JP-A-2011-237513 and a side-chain type liquid crystalline compound described in JP-A-2015-107492.

[0163] As a low-molecular liquid crystalline compound, it can be roughly classified into rod-shaped liquid crystalline compounds and disc-shaped liquid crystalline compounds according to the molecular shape. When the dichroic substance has a rod shape, from the point of view of improving the orientation order, a rod-shaped liquid crystalline compound is preferably used as the low-molecular liquid crystalline compound.

[0164] The high-molecular liquid crystalline compound can be roughly classified into a main-chain liquid crystalline compound and a side-chain liquid crystalline compound. The main-chain liquid crystalline compound refers to a compound having a structure indicating liquid crystallinity in the high-molecular main chain, and the side-chain liquid crystalline compound refers to a compound having a structure indicating liquid crystallinity in the high-molecular side-chain portion. A side-chain liquid crystalline compound is preferred in terms of the high orientation order of the obtained anisotropic light absorption layer and the excellent solubility in a solvent when preparing the composition.

[0165] The composition may contain other components in addition to the dichroic substance and the liquid crystalline compound.

[0166] The composition preferably contains a vertical alignment agent. If the composition contains a vertical alignment agent, the orientation of the dichroic substance and the liquid crystalline compound can be made more vertical, and the orientation order can be further improved.

[0167] Examples of the vertical alignment agent include boric acid compounds and onium salts.

[0168] Examples of the other components include a leveling agent, a polymerization initiator, and a solvent.

[0169] The method for forming the anisotropic light absorption layer using the above composition is not particularly limited, and examples thereof include a method sequentially including the following steps: a step of coating the above composition on a specified substrate to form a coating film (hereinafter, also referred to as "coating film forming step"); a step of aligning the liquid crystalline component contained in the coating film (hereinafter, also referred to as "alignment step"); and a step of performing a curing treatment on the coating film (hereinafter, also referred to as "curing step").

[0170] Hereinafter, the above steps will be described in detail.

[0171] The coating film forming step is a step of coating the composition on a specified substrate to form a coating film.

[0172] The type of the substrate is not particularly limited, and examples thereof include a transparent support and a laminate having an alignment film disposed on the transparent support.

[0173] The coating method of the composition is not particularly limited, and examples thereof include known methods.

[0174] The alignment step is a step of aligning the liquid crystalline component contained in the coating film.

[0175] The alignment process may include a drying treatment. Through the drying treatment, components such as solvents can be removed from the coating film.

[0176] The alignment process preferably includes a heating treatment. Thereby, the liquid crystal components contained in the coating film can be aligned.

[0177] The alignment process may include a cooling treatment performed after the heating treatment.

[0178] The curing process is carried out, for example, by heating and / or light irradiation (exposure). Among them, the curing process is preferably carried out by light irradiation.

[0179] (Mode 3)

[0180] As the light control component, a louver layer in which light-transmitting bands and light-shielding bands are alternately and repeatedly arranged can be cited.

[0181] Hereinafter, the mode of the louver layer will be described with reference to the drawings.

[0182] As Figure 5 shown, in the louver layer 40, light-transmitting bands 42 and light-shielding bands 44 are alternately arranged. A first transparent protective layer 46 is laminated on one surface of the louver layer 40, and a second transparent protective layer 48 is laminated on the other surface.

[0183] In addition, Figure 6 is a cross-sectional view taken along the line II-II in Figure 5 .

[0184] In addition, in the liquid crystal display device, as long as it includes a louver layer, the first transparent protective layer 46 and the second transparent protective layer 48 may or may not be included.

[0185] If the thickness direction of the louver layer 40 is set as the Z direction, and two mutually perpendicular directions in the plane perpendicular to the Z direction are respectively set as the X direction and the Y direction, then both the light-transmitting bands 42 and the light-shielding bands 44 constituting the louver layer 40 are strip-shaped extending along the X direction, and a plurality of light-transmitting bands 42 and a plurality of light-shielding bands 44 are alternately arranged in the Y direction. The widths of the plurality of light-transmitting bands 42 in the Y direction are uniform and constant in the X direction. And the widths of the plurality of light-shielding bands 44 in the Y direction are also uniform and constant in the X direction.

[0186] As the material of the light-transmitting band 42, a resin with high transparency and low birefringence of transmitted light is used. From the viewpoint of transparency, only for the light-transmitting band 42, a resin material with a high transparency having a light transmittance of 75% or more, preferably 85% or more when light is transmitted in the Z direction in the figure is preferably used.

[0187] For example, specific examples of resins with high transparency and low birefringence include silicone resins, polycarbonate resins, polyolefin resins (especially cycloolefin polymers), cellulose resins, and acrylic resins. Among them, silicone resins are preferred, and silicone rubbers are more preferred in terms of particularly good heat resistance.

[0188] In addition, the value of the above "light transmittance" is set as follows. That is, when using D65 specified in JIS Z8720 as the light source and using a device that measures the intensity of the inspection light emitted from the light source with a light receiving sensor, the output value of the light receiving sensor in the state where there is no object to be measured on the optical path of the inspection light is set as A, and the output value in the state where the object to be measured is set on the optical path of the inspection light and the transmitted light passing through the object to be measured is received by the light receiving sensor is set as B, the value obtained by light transmittance = (B / A) × 100 (unit: %) is calculated.

[0189] As the material of the light-shielding band 44, a colored resin obtained by using the resin listed above as the material of the light-transmitting band 42 as the base material and adding colorants such as pigments and dyes is preferably used. The color tone of the light-shielding band 44 only needs to obtain the preferred light-shielding property in the light-shielding band 44. For example, black, red, yellow, green, blue, and light blue can be cited. The color tone of the light-shielding band 44 can be adjusted according to the type and addition amount of the colorant. Specifically, only for the light-shielding band 44, it is preferably provided with a light-shielding property such that the light transmittance when light is transmitted in the Y direction in the figure is 40% or less (preferably 10% or less).

[0190] As the colorant, for example, general organic pigments or inorganic pigments such as carbon black, iron oxide red, iron oxide, titanium oxide, yellow iron oxide, bisazo yellow, and phthalocyanine blue can be cited. One type of colorant can be used, or two or more types can be used. And when not using black pigments, in order to obtain good light-shielding property, it is preferable to use white pigments in combination.

[0191] In the louver layer 40, the resin material forming the light-transmitting band 42 and the resin material serving as the base material of the light-shielding band 44 can be the same or different, but considering the adhesiveness between the light-transmitting band 42 and the light-shielding band 44, it is preferable that both are the same.

[0192] In the louver layer 40, the viewing angle θ in the plane perpendicular to the X direction ( Figure 6 the paper surface in the figure) is determined by the thickness in the Z direction and the width in the Y direction of the light-transmitting band 42. And the ratio of the width of the light-transmitting band 42 in the Y direction to the width of the light-shielding band 44 affects the transmittance of the light parallel to the Z direction.

[0193] Specifically, the viewing angle θ in the louver layer 40 is preferably 30 to 150°, more preferably 60 to 120°.

[0194] The thickness T of the light-transmitting band 42 in the Z direction is preferably 50 to 200 μm, more preferably 100 to 200 μm.

[0195] The width W1 of the light-transmitting band 42 in the Y direction is preferably 30 to 300 μm, more preferably 50 to 200 μm.

[0196] The width W2 of the light-shielding band 44 in the Y direction is preferably 5 to 30 μm, more preferably 10 to 20 μm.

[0197] The preferred range of the thickness T of the light-shielding band 44 in the Z direction is the same as the preferred range of the thickness T of the light-transmitting band 42.

[0198] The materials of the first transparent protective layer 46 and the second transparent protective layer 48 are resins with high transparency, and resins with small in-plane birefringence deviation are preferred.

[0199] From the perspective of transparency, the light transmittance when light is transmitted in the Z direction in the figure is preferably 75% or more, more preferably 85% or more, with respect to each monomer of the first transparent protective layer 46 and the second transparent protective layer 48.

[0200] As specific examples of resins with high transparency and small in-plane birefringence deviation in the state of being formed into a film, polycarbonate resins, polyolefin resins (especially, cycloolefin polymers), cellulose-based resins, or acrylic resins are preferred, and polycarbonate resins are more preferred.

[0201] The thicknesses of the first transparent protective layer 46 and the second transparent protective layer 48 are preferably 0.01 to 0.2 mm, more preferably 0.01 to 0.1 mm.

[0202] The first transparent protective layer 46 and the second transparent protective layer 48 may be made of the same material or different materials. And the thicknesses of the two may be the same or different.

[0203] The first transparent protective layer 46 and the second transparent protective layer 48 are preferably bonded and integrated with the louver layer 40 via an unillustrated adhesive layer.

[0204] There is no particular limitation on the manufacturing method of the above louver layer. For example, the manufacturing method described in Japanese Patent Laid-Open No. 2007-086142 can be cited.

[0205] In the above, the way in which the light-transmitting band and the light-shielding band extend in the thickness direction has been described, but it is not limited to this way, and it may also be a way in which the light-transmitting band and the light-shielding band are inclined with respect to the thickness direction.

[0206] In the above, the way in which the light-transmitting band and the light-shielding band have a constant width in the thickness direction has been described, but it is not limited to this way, and it may also be a way in which the width becomes narrower or wider as it faces one direction.

[0207] As described above, the structures of the light-transmitting band and the light-shielding band can be appropriately adjusted.

[0208] <Other components>

[0209] The liquid crystal display device may have other components in addition to the above-described components.

[0210] In terms of the more excellent effects of the present invention, the liquid crystal display device preferably has a second optically anisotropic layer including a positive A plate satisfying the relationships of formulas (7) to (8) and a positive C plate satisfying the relationships of formulas (9) to (10) in at least one of between the first polarizer and the liquid crystal cell and between the second polarizer and the liquid crystal cell.

[0211] Formula (7) 80 nm ≤ ReA(550) ≤ 160 nm

[0212] Formula (8) 0.75 < ReA(450) / ReA(550) < 1.00

[0213] Formula (9) -160 nm ≤ RthC(550) ≤ -60 nm

[0214] Formula (10) 0.75 < RthC(450) / RthC(550) < 1.00

[0215] ReA(550) represents the retardation of the positive A plate at a wavelength of 550 nm. ReA(450) represents the retardation of the positive A plate at a wavelength of 450 nm. RthC(550) represents the retardation in the thickness direction of the positive C plate at a wavelength of 550 nm. RthC(450) represents the retardation in the thickness direction of the positive C plate at a wavelength of 450 nm.

[0216] In terms of the more excellent effects of the present invention, the above positive A plate preferably satisfies the relationships of formulas (7A) to (8A).

[0217] Formula (7A) 110 nm ≤ ReA(550) ≤ 140 nm

[0218] Formula (8A) 0.80 < ReA(450) / ReA(550) < 0.95

[0219] In terms of the more excellent effects of the present invention, the above positive C plate preferably satisfies the relationships of formulas (9A) to (10A).

[0220] Formula (9A) -130 nm ≤ RthC(550) ≤ -90 nm

[0221] Formula (10A) 0.80 < RthC(450) / RthC(550) < 0.95

[0222] As long as the second optically anisotropic layer satisfies the above optical properties, its structure is not particularly limited. For example, a polymer film (especially a stretched polymer film) and a film formed using a liquid crystalline compound can be mentioned.

[0223] The liquid crystal display device preferably has a third optically anisotropic layer satisfying the relationships of formulas (11) to (12) in at least one of between the first polarizer and the liquid crystal cell and between the second polarizer and the liquid crystal cell.

[0224] Formula (11) 200 nm ≤ Re3(550) ≤ 400 nm

[0225] Formula (12) 0 nm ≤ |Rth3(550)| ≤ 50 nm

[0226] Re3(550) represents the in-plane retardation of the third optically anisotropic layer at a wavelength of 550 nm. Rth3(550) represents the retardation in the thickness direction of the third optically anisotropic layer at a wavelength of 550 nm. In addition, in formula (12), |Rth3(550)| represents the absolute value of Rth3(550).

[0227] In terms of the more excellent effects of the present invention, the above third optically anisotropic layer preferably satisfies formulas (11A) to (12A).

[0228] Formula (11A) 250 nm ≤ Re3(550) ≤ 350 nm

[0229] Formula (12A) 0 nm ≤ |Rth3(550)| ≤ 20 nm

[0230] As long as the third optically anisotropic layer satisfies the above optical properties, its structure is not particularly limited. For example, a polymer film (especially a stretched polymer film) and a film formed using a liquid crystalline compound can be mentioned.

[0231] (Light diffusion plate)

[0232] The liquid crystal display device can have a light diffusion plate. The light diffusion plate is preferably disposed between the light control member and the direct-lit backlight.

[0233] The light diffusion plate refers to a plate that is used to disrupt the traveling direction of the incident light and can emit light with uniform brightness from the main surface (plate surface).

[0234] As the light diffusion plate, a known light diffusion plate can be used.

[0235] (Brightness enhancement film)

[0236] A liquid crystal display device may have a brightness enhancement film. The brightness enhancement film is preferably disposed between the light control member and the direct - type backlight. In addition, the brightness enhancement film is preferably disposed on the side closer to the visual recognition side (the side opposite to the direct - type backlight) than the above - mentioned light diffusing plate.

[0237] As the brightness enhancement film, for example, a reflective polarizing film can be cited. The reflective polarizing film has a function of separating linearly polarized light. For example, when disposed between the second polarizer and the direct - type backlight, it has a function of reflecting or scattering linearly polarized light backward to the side of the direct - type backlight.

[0238] As a multi - layer type brightness enhancement film using the principle of a dielectric mirror, DBEF - E, DBEF - D, DBEF - M, DBEF - P2 (all manufactured by 3M Company) can be cited.

[0239] Examples

[0240] Hereinafter, examples and comparative examples will be given to further specifically illustrate the features of the present invention. The materials, amounts used, ratios, processing contents, processing sequences, etc. shown in the following examples can be appropriately changed as long as they do not depart from the gist of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

[0241] <Example 1>

[0242] An optically anisotropic film 1 with Re(550) of 100 nm, Rth(550) of - 300 nm, and an Nz coefficient of - 2.5 was produced by biaxially stretching ARTON (manufactured by JSR Corporation).

[0243] After that, the above - mentioned optically anisotropic film 1 was attached via an adhesive to the second polarizer disposed on the backlight side of ProArt PA32UCX manufactured by ASUS Corporation, which successively has a first polarizer, a liquid crystal cell, a second polarizer, a brightness enhancement film, a light diffusing plate, and a direct - type backlight. The optically anisotropic film 1 was disposed between the second polarizer and the direct - type backlight (which is also equivalent to between the second polarizer and the brightness enhancement film), thereby manufacturing the liquid crystal display device of Example 1.

[0244] In addition, in the above - mentioned direct - type backlight, a plurality of mini - LEDs were mounted as point light sources.

[0245] <Example 2>

[0246] (Formation of the alignment film)

[0247] The surface of a cellulose acylate film (a TAC substrate with a thickness of 40 μm; TG40 FUJIFILM Corporation) was saponified with an alkaline solution, and a composition for forming an alignment film was coated thereon with a wire bar. The support having the coating film formed thereon was dried with warm air at 60°C for 60 seconds, and then further dried with warm air at 100°C for 120 seconds to form an alignment film, thereby obtaining a TAC film with an alignment film. The film thickness of the alignment film was 1 μm.

[0248]

[0249] Modified polyvinyl alcohol PVA-1

[0250] [Chemical formula 1]

[0251]

[0252] (Formation of the light absorption anisotropic layer)

[0253] On the obtained alignment film, the following composition for forming a light absorption anisotropic layer was continuously coated with a wire bar. After heating the obtained coating film at 120°C for 60 seconds, it was cooled until it reached room temperature (23°C).

[0254] Next, the support having the coating film formed thereon was heated at 80°C for 60 seconds and cooled again until it reached room temperature.

[0255] After that, for the obtained coating film, an LED lamp (center wavelength 365 nm) was used to irradiate it for 2 seconds under irradiation conditions of an illuminance of 200 mW / cm 2 Thereby, a light absorption anisotropic layer was formed on the alignment film.

[0256] The film thickness of the light absorption anisotropic layer was 3.0 μm. The transmittance of the light absorption anisotropic layer at a wavelength of 550 nm was 80%, and the degree of orientation was 0.97. And the angle formed by the transmission axis of the above optical anisotropic layer and the normal direction of the light absorption anisotropic layer was 0°.

[0257]

[0258] Dichroic substance D-1

[0259] [Chemical formula 2]

[0260]

[0261] Dichroic substance D-2 [Chemical formula 3]

[0262]

[0263] Dichroic substance D-3 [Chemical formula 4]

[0264]

[0265] Polymer liquid crystalline compound P-1 [Chemical formula 5]

[0266]

[0267] Compound E-1

[0268] [Chemical formula 6]

[0269]

[0270] Compound E-2

[0271] [Chemical formula 7]

[0272]

[0273] Surfactant F-1 [Chemical formula 8]

[0274]

[0275] (Formation of the color adjustment layer)

[0276] The following color adjustment layer forming composition was continuously coated on the obtained light absorption anisotropic layer with a wire bar to form a coating film.

[0277] Next, the support having the coating film formed thereon was dried with warm air at 60 °C for 60 seconds, and then further dried with warm air at 100 °C for 120 seconds to form a color adjustment layer, which was used as an optical film.

[0278] The film thickness of the color adjustment layer was 0.5 μm.

[0279]

[0280] Pigment compound G-1

[0281] [Chemical formula 9]

[0282]

[0283] After that, the above optical film was adhered via an adhesive to the second polarizer disposed on the backlight side of ProArt PA32UCX manufactured by ASUS Corporation, which successively has a first polarizer, a liquid crystal cell, a second polarizer, and a direct-lit backlight. The above optical film was disposed between the second polarizer and the direct-lit backlight (which is also equivalent to between the second polarizer and the brightness enhancement film), thereby manufacturing the liquid crystal display device of Example 2.

[0284] <Example 3>

[0285] The optical anisotropic film 1 produced in Example 1 and the optical film including the light absorption anisotropic layer produced in Example 2 were adhered via an adhesive to the second polarizer disposed on the backlight side of ProArt PA32UCX manufactured by ASUS Corporation, which sequentially has a first polarizer, a liquid crystal cell, a second polarizer, and a direct-lit backlight. The above-mentioned optical anisotropic film 1 and optical film were disposed between the second polarizer and the direct-lit backlight (which is also equivalent to between the second polarizer and the brightness enhancement film), thereby manufacturing the liquid crystal display device of Example 3.

[0286] <Example 4>

[0287] Using the method described in Japanese Patent Application Laid-Open No. 2007-086142, a Figure 6 louver layer was fabricated in which the width W2 of the light-shielding band shown is 15 μm, the width of the light-transmitting band W1 is 70 μm, the thickness T of the light-shielding band and the light-transmitting band is 150 μm, and the light-transmitting band and the light-shielding band are alternately and repeatedly arranged.

[0288] A liquid crystal display device was manufactured according to the same procedure as in Example 1, except that the louver layer was used instead of the optical anisotropic film. In addition, the louver layer was arranged such that the absorption axis of the second polarizer is orthogonal to the extending direction of the light-transmitting band of the louver layer.

[0289] <Example 5>

[0290] Using the method described in International Publication No. 2018 / 207798, an optical anisotropic film 2 composed of a positive A plate with Re(550) of 130 nm and Re(450) / Re(550) = 0.86 and a positive C plate with Rth(550) of -105 nm and Rth(450) / Rth(550) = 0.90 was fabricated.

[0291] Subsequently, the above-mentioned optical anisotropic film 2 was disposed between the first polarizer and the liquid crystal cell in the liquid crystal display device manufactured in Example 3, thereby manufacturing a liquid crystal display device. In addition, the optical anisotropic film 2 was arranged such that the slow axis of the optical anisotropic film 2 is parallel to the absorption axis of the first polarizer.

[0292] <Example 6>

[0293] Using the method described in Japanese Patent Application Laid-Open No. 2006-72309, an optical anisotropic film 3 with Re(550) of 280 nm and |Rth(550)| of 0 nm was fabricated.

[0294] Subsequently, the above optical anisotropic film 3 was disposed between the second polarizer and the liquid crystal cell in the liquid crystal display device fabricated in Example 3, thereby fabricating a liquid crystal display device. Further, the optical anisotropic film 3 was disposed such that the slow axis of the optical anisotropic film 3 was orthogonal to the absorption axis of the second polarizer.

[0295] <Example 7>

[0296] The above optical anisotropic film 2 was disposed between the first polarizer and the liquid crystal cell in the liquid crystal display device fabricated in Example 4, thereby fabricating a liquid crystal display device. Further, the optical anisotropic film 2 was disposed such that the slow axis of the optical anisotropic film 2 was parallel to the absorption axis of the first polarizer.

[0297] <Example 8>

[0298] The above optical anisotropic film 3 was disposed between the second polarizer and the liquid crystal cell in the liquid crystal display device fabricated in Example 4, thereby fabricating a liquid crystal display device. Further, the optical anisotropic film 3 was disposed such that the slow axis of the optical anisotropic film 3 was orthogonal to the absorption axis of the second polarizer.

[0299] <Comparative Examples 1 and 2>

[0300] By changing the types of the light diffusion plate and the brightness enhancement film in the ProArt PA32UCX manufactured by ASUS Corporation, which sequentially includes a first polarizer, a liquid crystal cell, a second polarizer, a brightness enhancement film, a light diffusion plate, and a direct-lit backlight, a liquid crystal display device satisfying I20 / I0, I40 / I0, and I60 / I0 shown in Table 1 described later was fabricated.

[0301] <Comparative Example 3>

[0302] Using the method described in Japanese Unexamined Patent Application Publication No. 2007-086142, a Figure 6 louver layer was fabricated in which the width of the light-shielding band W2 was 30 μm, the width of the light-transmitting band W1 was 20 μm, the thickness T of the light-shielding band and the light-transmitting band was 300 μm, and the light-transmitting band and the light-shielding band were alternately and repeatedly arranged.

[0303] A liquid crystal display device was fabricated according to the same procedure as in Example 1, except that the louver layer was used instead of the optical anisotropic film. Further, the louver layer was disposed such that the absorption axis of the second polarizer was orthogonal to the extending direction of the light-transmitting band of the louver layer.

[0304] <Measurement of I20 / I0, I40 / I0, and I60 / I0>

[0305] The above I0, I20, I40, and I60 are obtained by displaying the liquid crystal display device as white in a dark room and measuring the white luminance at specified polar angle positions and azimuth angle positions using a measuring machine (EZ-Contrast XL88, manufactured by ELDIM Company).

[0306] More specifically, in a dark room, the liquid crystal display device is set to white display, and the measuring machine is placed at a position where the polar angle is 0° (θ in Figure 2 is 0°) and the azimuth angle is 0° (φ in Figure 2 is 0°), and I0 is obtained by measuring the luminance.

[0307] Regarding I20, first, in a dark room, the liquid crystal display device is set to white display, and the measuring machine is placed at a position where the polar angle is 20° (θ in Figure 2 is 20°) and the azimuth angle is 45° (φ in Figure 2 is 45°) to obtain the luminance (luminance 20A). Then, the measuring machine is placed at a position where the polar angle is 20° (θ in Figure 2 is 20°) and the azimuth angle is 135° (φ in Figure 2 is 135°) to obtain the luminance (luminance 20B). Next, the measuring machine is placed at a position where the polar angle is 20° (θ in Figure 2 is 20°) and the azimuth angle is 225° (φ in Figure 2 is 225°) to obtain the luminance (luminance 20C). Finally, the measuring machine is placed at a position where the polar angle is 20° (θ in Figure 2 is 20°) and the azimuth angle is 315° (φ in Figure 2 is 315°) to obtain the luminance (luminance 20D). Subsequently, the arithmetic mean of the four obtained luminances (luminance 20A, luminance 20B, luminance 20C, luminance 20D) is calculated to obtain the average luminance, which is set as I20.

[0308] Regarding I40, first, in a dark room, the liquid crystal display device is set to white display, and the measuring machine is placed at a position where the polar angle is 40° (θ in Figure 2 is 40°) and the azimuth angle is 45° (φ in Figure 2 is 45°) to obtain the luminance (luminance 40A). Then, the measuring machine is placed at a position where the polar angle is 40° (θ in Figure 2 is 40°) and the azimuth angle is 135° (φ in Figure 2 is 135°) to obtain the luminance (luminance 40B). Next, the measuring machine is placed at a position where the polar angle is 40° (θ in Figure 2 is 40°) and the azimuth angle is 225° (φ in Figure 2 is 225°) to obtain the luminance (luminance 40C). Finally, the measuring machine is placed at a position where the polar angle is 40° (θ in Figure 2 is 40°) and the azimuth angle is 315° ( Figure 2 The brightness (brightness 40D) is obtained by arranging a measuring machine at a position where φ in it is 315°. Next, the arithmetic mean of the four obtained brightness values (brightness 40A, brightness 40B, brightness 40C, brightness 40D) is calculated to obtain the average brightness, which is designated as I40.

[0309] And for I60, first, the liquid crystal display device is set to white display in a dark room, and at a polar angle of 60° ( Figure 2 where θ in it is 60°) and an azimuth angle of 45° ( Figure 2 where φ in it is 45°), a measuring machine is arranged to obtain the brightness (brightness 60A). At a polar angle of 60° ( Figure 2 where θ in it is 60°) and an azimuth angle of 135° ( Figure 2 where φ in it is 135°), a measuring machine is arranged to obtain the brightness (brightness 60B). At a polar angle of 60° ( Figure 2 where θ in it is 60°) and an azimuth angle of 225° ( Figure 2 where φ in it is 225°), a measuring machine is arranged to obtain the brightness (brightness 60C). At a polar angle of 60° ( Figure 2 where θ in it is 60°) and an azimuth angle of 315° ( Figure 2 where φ in it is 315°), a measuring machine is arranged to obtain the brightness (brightness 60D). Next, the arithmetic mean of the four obtained brightness values (brightness 60A, brightness 60B, brightness 60C, brightness 60D) is calculated to obtain the average brightness, which is designated as I60.

[0310] <Display quality evaluation>

[0311] The entire surface of the liquid crystal display devices fabricated in each of the examples and comparative examples was set to blue display, and the display quality was evaluated according to the following criteria by observing the liquid crystal display device from the front at a position 50 cm away from the liquid crystal display device.

[0312] A: Excellent display quality (brightness, chroma) is achieved over the entire surface.

[0313] B: A slight reduction in display quality is observed at the edges of the screen, but it is not a concern.

[0314] C: The reduction in display quality at the edges of the screen is a concern.

[0315] <Halation evaluation>

[0316] Using the liquid crystal display devices fabricated in each of the examples and comparative examples, when displaying an image as shown in Figure 7 a circle with a diameter of 5 cm of white display arranged at intervals of 10 cm on a black background, the halation around the white display part was observed by observing the liquid crystal display device from the front at a position 50 cm away from the liquid crystal display device, and the evaluation was carried out according to the following criteria.

[0317] A: No halation visually recognized

[0318] B: Halation visually recognized, but not bothered

[0319] C: Halation visually recognized and bothered

[0320] In Table 1, the column of "Method" indicates which one of the above-described Method 1 (the method using the first optically anisotropic layer), Method 2 (the method using the light absorption anisotropic layer), and Method 3 (the method using the louver layer). "Method 1 and Method 2" corresponds to the method using both the first optically anisotropic layer and the light absorption anisotropic layer.

[0321] In Table 1, in the column of "Second optically anisotropic layer", the case where the second optically anisotropic layer is used is indicated as "A", and the case where it is not used is indicated as "B".

[0322] In Table 1, in the column of "Third optically anisotropic layer", the case where the third optically anisotropic layer is used is indicated as "A", and the case where it is not used is indicated as "B".

[0323] [Table 1]

[0324]

[0325] As shown in Table 1, it was confirmed that the liquid crystal display device of the present invention exhibits the desired effects.

[0326] From the comparison between Example 3 and Examples 5 and 6, it was confirmed that more excellent effects are obtained when the second optically anisotropic layer or the third optically anisotropic layer is used.

[0327] From the comparison between Examples 1, 2, and 3, it was confirmed that more excellent effects are obtained when the louver layer is used.

[0328] From the comparison between Examples 1 to 3, it was confirmed that more excellent effects are obtained when both the first optically anisotropic layer and the light absorption anisotropic layer are used.

[0329] Symbol Explanation

[0330] 10 - Liquid crystal display device, 12 - First polarizer, 14 - Liquid crystal cell, 16 - Second polarizer, 18 - Light control member, 20, 30 - Direct-lit backlight, 22 - Upper substrate, 24 - Lower substrate, 26 - Liquid crystal layer, 32 - Substrate, 34 - Point light source, 40 - Louver layer, 42 - Light transmissive band, 44 - Light shielding band, 46 - First transparent protective layer, 48 - Second transparent protective layer.

Claims

1. A liquid crystal display device, which successively has: A first polarizer; A liquid crystal cell; A second polarizer; and A direct - type backlight using a point light source, wherein, A light control member is further provided between the second polarizer and the direct - type backlight, satisfying the relationships of the following formulas (1) to (3), Formula (1) 70% ≤ (I20 / I0) × 100 ≤ 90% Formula (2) 10% ≤ (I40 / I0) × 100 ≤ 35% Formula (3) 1% ≤ (I60 / I0) × 100 ≤ 20% When the absorption axis direction of the first polarizer is set as the azimuth angle 0°, and when representing the azimuth angle, observing from the visual recognition side and using the absorption axis direction of the first polarizer as a reference, the counter - clockwise direction is represented by a positive value, I0 represents the luminance measured at the polar angle 0° and the azimuth angle 0° with the liquid crystal display device set to white display, I20 represents the average luminance obtained by arithmetically averaging the luminance measured at the polar angle 20° and the azimuth angle 45°, the luminance measured at the polar angle 20° and the azimuth angle 135°, the luminance measured at the polar angle 20° and the azimuth angle 225°, and the luminance measured at the polar angle 20° and the azimuth angle 315° with the liquid crystal display device set to white display, I40 represents the average luminance obtained by arithmetically averaging the luminance measured at the polar angle 40° and the azimuth angle 45°, the luminance measured at the polar angle 40° and the azimuth angle 135°, the luminance measured at the polar angle 40° and the azimuth angle 225°, and the luminance measured at the polar angle 40° and the azimuth angle 315° with the liquid crystal display device set to white display, I60 represents the average luminance obtained by arithmetically averaging the luminance measured at the polar angle 60° and the azimuth angle 45°, the luminance measured at the polar angle 60° and the azimuth angle 135°, the luminance measured at the polar angle 60° and the azimuth angle 225°, and the luminance measured at the polar angle 60° and the azimuth angle 315° with the liquid crystal display device set to white display.

2. The liquid crystal display device according to claim 1, wherein, The light control member has a first optically anisotropic layer satisfying the relationships of formulas (4) to (6), Formula (4) 0nm ≤ Re1(550) ≤ 300nm Formula (5) 100nm ≤ |Rth1(550)| ≤ 1000nm Formula (6) |Nz| ≥ 1.2 Re1(550) represents the in - plane retardation of the first optically anisotropic layer at a wavelength of 550nm, Rth1(550) represents the retardation in the thickness direction of the first optically anisotropic layer at a wavelength of 55nm, and Nz represents the Nz coefficient of the first optically anisotropic layer.

3. The liquid crystal display device according to claim 1 or 2, wherein, The light control member has a light - absorbing anisotropic layer containing a dichroic substance, When the direction with the highest transmittance with respect to the surface of the light - absorbing anisotropic layer is set as the transmission axis, the angle formed by the normal direction of the light - absorbing anisotropic layer and the transmission axis is 0 to 45°.

4. The liquid crystal display device according to claim 1 or 2, wherein, The light control member has a louver layer in which light-transmitting bands and light-shielding bands are alternately and repeatedly arranged.

5. The liquid crystal display device according to claim 1 or 2, wherein in at least one of between the first polarizer and the liquid crystal cell and between the second polarizer and the liquid crystal cell, there is a second optically anisotropic layer including a positive A plate satisfying the relationships of formulas (7) to (8) and a positive C plate satisfying the relationships of formulas (9) to (10), Formula (7) 80 nm ≤ ReA(550) ≤ 160 nm Formula (8) 0.75 < ReA(450) / ReA(550) < 1.00 Formula (9) -160 nm ≤ RthC(550) ≤ -60 nm Formula (10) 0.75 < RthC(450) / RthC(550) < 1.00 ReA(550) represents the in-plane retardation of the positive A plate at a wavelength of 550 nm, ReA(450) represents the in-plane retardation of the positive A plate at a wavelength of 450 nm, RthC(550) represents the retardation in the thickness direction of the positive C plate at a wavelength of 550 nm, and RthC(450) represents the retardation in the thickness direction of the positive C plate at a wavelength of 450 nm.

6. The liquid crystal display device according to claim 1 or 2, wherein in at least one of between the first polarizer and the liquid crystal cell and between the second polarizer and the liquid crystal cell, there is a third optically anisotropic layer satisfying the relationships of formulas (11) to (12), Formula (11) 200 nm ≤ Re3(550) ≤ 400 nm Formula (12) 0 nm ≤ |Rth3(550)| ≤ 50 nm Re3(550) represents the in-plane retardation of the third optically anisotropic layer at a wavelength of 550 nm, and Rth3(550) represents the retardation in the thickness direction of the third optically anisotropic layer at a wavelength of 550 nm.

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