WO2017094529A1

WO2017094529A1 - Liquid crystal display device

Info

Publication number: WO2017094529A1
Application number: PCT/JP2016/084246
Authority: WO
Inventors: 敏行飯田
Original assignee: 日東電工株式会社
Priority date: 2015-11-30
Filing date: 2016-11-18
Publication date: 2017-06-08
Also published as: KR102565008B1; KR20230003306A; CN113917738A

Abstract

The purpose of the present invention is to provide a liquid crystal display device that has superior color reproducibility, superior visibility when viewed through an optical member, said optical member having a polarizing effect, and minimized color irregularity. A liquid crystal display device (500) according to the present invention comprises: a liquid crystal panel (100) that includes a liquid crystal cell (10), a first polarizer (20) positioned on a viewing side of the liquid crystal cell (10), and a second polarizer (30) positioned on a back surface side; a phase difference layer (200) that is positioned on the viewing side of the liquid crystal panel (100); and a backlight light source (300) that illuminates the liquid crystal panel (100) from the back surface side. The in-plane phase difference Re(550) of the phase difference layer (200) is 100nm-180nm and satisfies the relationship Re(450)<Re(550)<Re(650). The angle formed by the slow axis of the phase difference layer (200) and a long side of the liquid crystal panel (100) is 35°-55°. The backlight light source (300) has a discontinuous emission spectrum.

Description

Liquid crystal display

The present invention relates to a liquid crystal display device.

In recent years, liquid crystal display devices such as mobile phones, smartphones, tablet personal computers (PCs), car navigation systems, digital signage, window displays, etc. have been increasingly used under strong external light. Thus, when a liquid crystal display device is used outdoors, when a viewer views the liquid crystal display device wearing polarized sunglasses, the transmission axis direction of the polarized sunglasses and the emission of the liquid crystal display device depend on the viewing angle. As a result, the screen becomes black and the display image may not be visually recognized. In order to solve such a problem, a technique for arranging a λ / 4 plate or an ultrahigh retardation film on the viewing side of the liquid crystal display device has been proposed.

On the other hand, in order to improve the color reproducibility of the liquid crystal display device, an attempt has been made to bring the backlight light source closer to the characteristics of a single light source of red (R), green (G), and blue (B). However, in such an attempt, there is a problem that coloring and / or color unevenness occurs even if a λ / 4 plate or an ultrahigh retardation film is simply disposed on the viewing side of the liquid crystal display device as a countermeasure against polarized sunglasses.

JP 2005-352068 A JP2011-107198A

The present invention has been made in order to solve the above-described conventional problems, and the object of the present invention is excellent in color reproducibility and excellent in visibility when viewed through an optical member having a polarizing action and color. An object is to provide a liquid crystal display device in which unevenness is suppressed.

The liquid crystal display device of the present invention includes a liquid crystal panel including a liquid crystal cell, a first polarizer disposed on the viewing side of the liquid crystal cell, and a second polarizer disposed on the back side of the liquid crystal cell; A retardation layer disposed on the viewing side of the liquid crystal panel; and a backlight source that illuminates the liquid crystal panel from the back side. The in-plane retardation Re (550) of the retardation layer is 100 nm to 180 nm, and satisfies the relationship of Re (450) <Re (550) <Re (650). The angle formed by the slow axis of the retardation layer and the long side of the liquid crystal panel is 35 ° to 55 °. The backlight source has a discontinuous emission spectrum.
In one embodiment, the emission spectrum of the backlight source has a peak P1 in the wavelength region of 430 nm to 470 nm, a peak P2 in the wavelength region of 530 nm to 570 nm, and a peak P3 in the wavelength region of 630 nm to 670 nm. The wavelength of the peak P1 is λ1, the height is hP1 and the half width is Δλ1, the wavelength of the peak P2 is λ2, the height is hP2 and the half width is Δλ2, the wavelength of the peak P3 is λ3, the height is hP3 and the half width is Δλ3. When the height of the valley between the peak P1 and the peak P2 is hB1, and the height of the valley between the peak P2 and the peak P3 is hB2, these are expressed by the following relational expressions (1) to (3). Satisfy:
(Λ2−λ1) / (Δλ2 + Δλ1)> 1 (1)
(Λ3-λ2) / (Δλ3 + Δλ2)> 1 (2)
0.8 ≦ {hP2− (hB2 + hB1) / 2} / hP2 ≦ 1 (3).
In one embodiment, the refractive index ellipsoid of the retardation layer exhibits a relationship of nx>nz> ny, and the Nz coefficient is 0.2 to 0.8.
In one embodiment, the liquid crystal display device further includes another retardation layer whose refractive index ellipsoid shows a relationship of nz> nx ≧ ny between the liquid crystal panel and the retardation layer.
In one embodiment, the backlight source includes a red color LED, a green color LED, and a blue color LED, and the phosphor of the red color LED is a tetravalent manganese ion. It is activated. In another embodiment, the backlight source includes an LED that emits blue light and a wavelength conversion layer that includes quantum dots.
In one embodiment, the absorption axis of the first polarizer is substantially perpendicular or parallel to the long side of the liquid crystal panel, and the absorption axis of the second polarizer is the length of the liquid crystal panel. It is substantially orthogonal or parallel to the side, and the absorption axis of the first polarizer and the absorption axis of the second polarizer are substantially orthogonal.

According to an embodiment of the present invention, a retardation light source having a specific emission spectrum and using a backlight layer having a specific emission spectrum and a so-called reverse dispersion wavelength dependency and having a predetermined in-plane retardation are visually recognized at a specific axis angle. By disposing on the side, it is possible to realize a liquid crystal display device that is excellent in color reproducibility, excellent in visibility when viewed through an optical member having a polarizing action, and in which color unevenness is suppressed.

1 is a schematic cross-sectional view of a liquid crystal display device according to an embodiment of the present invention. It is a figure which shows typically an example of the emission spectrum of the backlight light source which can be used for the liquid crystal display device by embodiment of this invention. It is a figure which shows typically an example of the emission spectrum of the conventional backlight light source.

Hereinafter, representative embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

(Definition of terms and symbols)
The definitions of terms and symbols in this specification are as follows.
(1) Refractive index (nx, ny, nz)
“Nx” is the refractive index in the direction in which the in-plane refractive index is maximum (ie, the slow axis direction), and “ny” is the direction orthogonal to the slow axis in the plane (ie, the fast axis direction). “Nz” is the refractive index in the thickness direction.
(2) In-plane retardation (Re)
“Re (λ)” is the in-plane retardation of the film measured with light having a wavelength of λ nm at 23 ° C. For example, “Re (450)” is the in-plane retardation of the film measured with light having a wavelength of 450 nm at 23 ° C. Re (λ) is determined by the formula: Re = (nx−ny) × d, where d (nm) is the thickness of the film.
(3) Thickness direction retardation (Rth)
“Rth (λ)” is a retardation in the thickness direction of the film measured with light having a wavelength of 550 nm at 23 ° C. For example, “Rth (450)” is the retardation in the thickness direction of the film measured with light having a wavelength of 450 nm at 23 ° C. Rth (λ) is determined by the formula: Rth = (nx−nz) × d, where d (nm) is the thickness of the film.
(4) Nz coefficient The Nz coefficient is obtained by Nz = Rth / Re.
(5) nx = ny, nx = nz, ny = nz
nx = ny includes not only the case where nx and ny are completely the same, but also the case where nx and ny are substantially the same. The same applies to the relationship of nx = nz and ny = nz.
(6) Substantially orthogonal or parallel The expressions “substantially orthogonal” and “substantially orthogonal” include the case where the angle between the two directions is 90 ° ± 10 °, preferably 90 ° ± 7 °. And more preferably 90 ° ± 5 °. The expressions “substantially parallel” and “substantially parallel” include the case where the angle between two directions is 0 ° ± 10 °, preferably 0 ° ± 7 °, more preferably 0 ° ± 5 °. Furthermore, the term “orthogonal” or “parallel” may include a substantially orthogonal state or a substantially parallel state.
(7) Angle When this specification refers to an angle, the angle includes angles in both clockwise and counterclockwise directions unless otherwise specified.

A. 1 is a schematic sectional view of a liquid crystal display device according to an embodiment of the present invention. In the drawings, the thickness ratios of the respective layers and the respective optical members are different from actual ones for easy viewing. The liquid crystal display device 500 of this embodiment includes a liquid crystal panel 100, a retardation layer 200 disposed on the viewing side of the liquid crystal panel 100, and a backlight light source 300 that illuminates the liquid crystal panel 100 from the back side. In the illustrated example, another retardation layer 400 may be further disposed between the liquid crystal panel 100 and the retardation layer 200. Another retardation layer may be omitted according to the purpose, configuration, desired characteristics, and the like. For convenience, the retardation layer 200 may be referred to as a first retardation layer, and another retardation layer 400 may be referred to as a second retardation layer. In the embodiment of the present invention, the in-plane retardation Re (550) of the first retardation layer 200 is 100 nm to 180 nm, preferably 110 nm to 170 nm, more preferably 120 nm to 160 nm, and particularly preferably. Is from 135 nm to 155 nm. Further, the first retardation layer 200 satisfies the relationship of Re (450) <Re (550) <Re (650). In addition, in the embodiment of the present invention, the backlight source 300 has a discontinuous emission spectrum.

The liquid crystal panel 100 includes a liquid crystal cell 10, a first polarizer 20 disposed on the viewing side of the liquid crystal cell 10, and a second polarizer 30 disposed on the back side of the liquid crystal cell 10. The absorption axis of the first polarizer 20 is substantially orthogonal or parallel to the long side of the liquid crystal panel 100 (liquid crystal cell 10). The absorption axis of the second polarizer 30 is also substantially orthogonal or parallel to the long side of the liquid crystal panel 100 (liquid crystal cell 10). Note that the long side of the liquid crystal panel may be the left-right direction or the vertical direction of the display screen. The absorption axis of the first polarizer 20 and the absorption axis of the second polarizer 30 are substantially orthogonal. A protective film (not shown) may be disposed on one side or both sides of the first polarizer 20. Similarly, a protective film (not shown) may be disposed on one side or both sides of the second polarizer 30.

The angle formed between the slow axis of the first retardation layer 200 and the long side of the liquid crystal panel 100 is 35 ° to 55 °, preferably 38 ° to 52 °, more preferably 40 ° to 50 °. More preferably 42 ° to 48 °, particularly preferably 44 ° to 46 °, and particularly preferably about 45 °. Therefore, the angle formed by the slow axis of the first retardation layer 200 and the absorption axis of the first polarizer 20 is preferably 35 ° to 55 °, more preferably 38 ° to 52 °. More preferably, it is 40 ° to 50 °, particularly preferably 42 ° to 48 °, particularly preferably 44 ° to 46 °, and most preferably about 45 °.

In one embodiment, a conductive layer (not shown) may be provided between the first polarizer 20 and the liquid crystal cell 10. By providing such a conductive layer, the liquid crystal display device can function as a so-called inner touch panel type input display device in which a touch sensor is incorporated between a display cell (liquid crystal cell) and a polarizer.

If necessary, any appropriate optical compensation layer (further different position) is provided between the first polarizer 20 and the liquid crystal cell 10 and / or between the second polarizer 30 and the liquid crystal cell 10. A phase difference layer) may be disposed. The number, combination, arrangement position, arrangement order, optical characteristics (for example, refractive index ellipsoid, in-plane phase difference, thickness direction phase difference, Nz coefficient), mechanical characteristics, etc. of such an optical compensation layer are the purpose, It can be appropriately set according to the configuration and desired characteristics of the liquid crystal display device.

Hereinafter, components (optical film, optical member) of the liquid crystal display device will be described.

B. Liquid crystal panel B-1. Liquid Crystal Cell The liquid crystal cell 10 includes a pair of

substrates

11 and 12 and a liquid crystal layer 13 as a display medium sandwiched between the substrates. In a general configuration, one substrate 11 is provided with a color filter and a black matrix, and the other substrate 12 is provided with a switching element for controlling the electro-optical characteristics of the liquid crystal and a gate signal is given to this switching element. A scanning line and a signal line for supplying a source signal, a pixel electrode, and a counter electrode are provided. The distance (cell gap) between the

substrates

11 and 12 can be controlled by a spacer or the like. For example, an alignment film made of polyimide can be provided on the side of the

substrates

11 and 12 that is in contact with the liquid crystal layer 13.

In one embodiment, the liquid crystal layer 13 includes liquid crystal molecules aligned in a homogeneous alignment in the absence of an electric field. Such a liquid crystal layer (as a result, a liquid crystal cell) typically has a refractive index ellipsoid having a relationship of nx> ny = nz. Typical examples of drive modes using such a liquid crystal layer exhibiting a three-dimensional refractive index include an in-plane switching (IPS) mode and a fringe field switching (FFS) mode. The IPS mode includes a super-in-plane switching (S-IPS) mode and an advanced super-in-plane switching (AS-IPS) mode employing a V-shaped electrode or a zigzag electrode. The FFS mode includes an advanced fringe field switching (A-FFS) mode and an ultra fringe field switching (U-FFS) mode employing a V-shaped electrode or a zigzag electrode. In such a driving mode (for example, IPS mode or FFS mode) using liquid crystal molecules aligned in a homogeneous arrangement in the absence of an electric field, there is no oblique gradation inversion and the oblique viewing angle is wide. There is an advantage that the property is excellent.

In another embodiment, the liquid crystal layer 13 includes liquid crystal molecules aligned in a homeotropic alignment in the absence of an electric field. An example of a drive mode using liquid crystal molecules aligned in a homeotropic alignment in the absence of an electric field is a vertical alignment (VA) mode. The VA mode includes a multi-domain VA (MVA) mode. In a drive mode (for example, VA mode) using liquid crystal molecules aligned in a homeotropic alignment in the absence of such an electric field, the halftone transmittance in the oblique direction is higher than the halftone transmittance in the front direction. Therefore, there is an advantage that the halftone viewed from an oblique direction is bright and there is little blackout.

B-2. Polarizer Any appropriate polarizer may be adopted as the first polarizer 20 and the second polarizer 30. The materials, thicknesses, optical characteristics, and the like of the first polarizer 20 and the second polarizer 30 may be the same or different. Hereinafter, the first polarizer 20 and the second polarizer 30 may be collectively referred to as a polarizer.

The resin film forming the polarizer may be a single layer resin film or a laminate of two or more layers.

Specific examples of polarizers composed of a single-layer resin film include hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and ethylene / vinyl acetate copolymer partially saponified films. In addition, there may be mentioned polyene-based oriented films such as those subjected to dyeing treatment and stretching treatment with dichroic substances such as iodine and dichroic dyes, PVA dehydrated products and polyvinyl chloride dehydrochlorinated products. Preferably, a polarizer obtained by dyeing a PVA film with iodine and uniaxially stretching is used because of excellent optical properties.

The dyeing with iodine is performed, for example, by immersing a PVA film in an aqueous iodine solution. The stretching ratio of the uniaxial stretching is preferably 3 to 7 times. The stretching may be performed after the dyeing treatment or may be performed while dyeing. Moreover, you may dye | stain after extending | stretching. If necessary, the PVA film is subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment and the like. For example, by immersing the PVA film in water and washing it before dyeing, not only can the surface of the PVA film be cleaned of dirt and anti-blocking agents, but the PVA film can be swollen to cause uneven staining. Can be prevented.

As a specific example of a polarizer obtained by using a laminate, a laminate of a resin substrate and a PVA resin layer (PVA resin film) laminated on the resin substrate, or a resin substrate and the resin Examples thereof include a polarizer obtained by using a laminate with a PVA resin layer applied and formed on a substrate. For example, a polarizer obtained by using a laminate of a resin base material and a PVA resin layer applied and formed on the resin base material may be obtained by, for example, applying a PVA resin solution to a resin base material and drying it. A PVA-based resin layer is formed thereon to obtain a laminate of a resin base material and a PVA-based resin layer; the laminate is stretched and dyed to make the PVA-based resin layer a polarizer; obtain. In the present embodiment, stretching typically includes immersing the laminate in an aqueous boric acid solution and stretching. Furthermore, the stretching may further include, if necessary, stretching the laminate in the air at a high temperature (for example, 95 ° C. or higher) before stretching in the aqueous boric acid solution. The obtained resin base material / polarizer laminate may be used as it is (that is, the resin base material may be used as a protective layer of the polarizer), and the resin base material is peeled from the resin base material / polarizer laminate. Any appropriate protective layer according to the purpose may be laminated on the release surface. Details of a method for manufacturing such a polarizer are described in, for example, Japanese Patent Application Laid-Open No. 2012-73580. This publication is incorporated herein by reference in its entirety.

The thickness of the polarizer is preferably 15 μm or less, more preferably 1 μm to 12 μm, still more preferably 3 μm to 10 μm, and particularly preferably 3 μm to 8 μm. When the thickness of the polarizer is in such a range, curling during heating can be satisfactorily suppressed, and good appearance durability during heating can be obtained. Furthermore, if the thickness of the polarizer is in such a range, it can contribute to the thinning of the liquid crystal display device.

The polarizer preferably exhibits absorption dichroism at any wavelength between 380 nm and 780 nm. The single transmittance of the polarizer is preferably 43.0% to 46.0%, more preferably 44.5% to 46.0%. The polarization degree of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and further preferably 99.9% or more.

As described above, a protective film may be disposed on one side or both sides of the first polarizer 20, and a protective film may be disposed on one side or both sides of the second polarizer 30. That is, the polarizer may be a component of the liquid crystal display device alone, or may be a component of the liquid crystal display device as a polarizing plate including the polarizer and the protective film. Further, the polarizer and the protective film may be separately laminated (that is, the polarizer and the protective film, respectively) to be a constituent element of the liquid crystal display device.

The protective film is formed of any appropriate film. Specific examples of the material as the main component of the film include cellulose resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, and polysulfone-based materials. And transparent resins such as polystyrene, polynorbornene, polyolefin, (meth) acryl, and acetate. Further, thermosetting resins such as (meth) acrylic, urethane-based, (meth) acrylurethane-based, epoxy-based, and silicone-based or ultraviolet curable resins are also included. In addition to this, for example, a glassy polymer such as a siloxane polymer is also included. Further, a polymer film described in JP-A-2001-343529 (WO01 / 37007) can also be used. As a material for this film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and nitrile group in the side chain For example, a resin composition having an alternating copolymer of isobutene and N-methylmaleimide and an acrylonitrile / styrene copolymer can be mentioned. The polymer film can be, for example, an extruded product of the resin composition.

The thickness of the protective film is preferably 20 μm to 200 μm, more preferably 30 μm to 100 μm, and still more preferably 35 μm to 95 μm.

When a protective film (inner protective film) is disposed on the liquid crystal cell 10 side of the first polarizer 20 and / or the second polarizer 30, the inner protective film may be optically isotropic. preferable. In this specification, “optically isotropic” means that the in-plane retardation Re (550) is 0 nm to 10 nm and the thickness direction retardation Rth (550) is −10 nm to +10 nm. Say.

C. First retardation layer As described above, the in-plane retardation Re (550) of the first retardation layer 200 is 100 nm to 180 nm, preferably 110 nm to 170 nm, more preferably 120 nm to 160 nm, Particularly preferred is 135 nm to 155 nm. That is, the first retardation layer can function as a so-called λ / 4 plate. Therefore, the first retardation layer has a function of converting linearly polarized light emitted from the polarizer to the viewer side into elliptically polarized light or circularly polarized light. In this way, by disposing the first retardation layer that can function as a λ / 4 plate on the viewer side with respect to the viewer side polarizer (first polarizer 20) with the specific axial relationship as described above, Even when the display screen is viewed through an optical member having a polarizing action (for example, polarized sunglasses), excellent visibility can be realized. Therefore, the liquid crystal display device of the present invention can be suitably used outdoors.

Further, as described above, the first retardation layer satisfies the relationship of Re (450) <Re (550) <Re (650). That is, the first retardation layer shows the wavelength dependence of reverse dispersion in which the retardation value increases with the wavelength of the measurement light. Re (450) / Re (550) of the first retardation layer is preferably 0.8 or more and less than 1.0, and more preferably 0.8 to 0.95. Re (550) / Re (650) is preferably 0.8 or more and less than 1.0, and more preferably 0.8 to 0.97.

The first retardation layer typically has a refractive index characteristic of nx> ny and has a slow axis. As described above, the angle formed between the slow axis of the first retardation layer 200 and the absorption axis of the first polarizer 20 is preferably 35 ° to 55 °, more preferably 38 ° to 52 °. More preferably 40 ° to 50 °, particularly preferably 42 ° to 48 °, particularly preferably 44 ° to 46 °, and most preferably about 45 °. If the angle is in such a range, the first retardation layer is a λ / 4 plate, and the first retardation layer is arranged on the viewing side with respect to the first polarizer (viewing side polarizer). Thus, even when the display screen is viewed through an optical member having a polarizing action (for example, polarized sunglasses), excellent visibility can be realized. Therefore, the liquid crystal display device of the present invention can be suitably used even outdoors.

The first retardation layer exhibits any appropriate refractive index ellipsoid as long as it has a relationship of nx> ny. Preferably, the refractive index ellipsoid of the first retardation layer shows a relationship of nx> nz> ny. The Nz coefficient of the first retardation layer is preferably 0.2 to 0.8, more preferably 0.3 to 0.7, still more preferably 0.4 to 0.6, particularly Preferably it is about 0.5. By satisfying such a relationship, there is an advantage that coloring is suppressed when viewed from an oblique direction through an optical member having a polarizing action (for example, polarized sunglasses).

The absolute value of the photoelastic coefficient of the first retardation layer is preferably 2 × 10 ⁻¹¹ m ² / N or less, more preferably 2.0 × 10 ⁻¹³ m ² / N to 1.5 × 10 ^−11. m ² / N, more preferably from ^{^{^{1.0 × 10 -12 m 2 /N~1.2×10 -11}}} m 2 / N resin. When the absolute value of the photoelastic coefficient is in such a range, a phase difference change is unlikely to occur when a shrinkage stress is generated during heating. As a result, the thermal unevenness of the liquid crystal display device can be satisfactorily prevented.

The thickness of the first retardation layer can be set so as to function most appropriately as a λ / 4 plate. In other words, the thickness can be set so as to obtain a desired in-plane retardation. Specifically, the thickness is preferably 1 μm to 80 μm, more preferably 10 μm to 80 μm, still more preferably 10 μm to 60 μm, and particularly preferably 30 μm to 50 μm.

The first retardation layer is formed of any appropriate resin that can satisfy the above characteristics. Examples of the resin that forms the first retardation layer include polycarbonate resins, polyvinyl acetal resins, cycloolefin resins, acrylic resins, and cellulose ester resins. Polycarbonate resin is preferable.

As the polycarbonate resin, any appropriate polycarbonate resin can be used as long as the effects of the present invention can be obtained. Preferably, the polycarbonate resin includes a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, an alicyclic diol, an alicyclic dimethanol, di, tri, or polyethylene glycol, and an alkylene. A structural unit derived from at least one dihydroxy compound selected from the group consisting of glycol or spiroglycol. Preferably, the polycarbonate resin is derived from a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, a structural unit derived from an alicyclic dimethanol and / or a di-, tri- or polyethylene glycol. More preferably, a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, and a structural unit derived from di, tri, or polyethylene glycol. The polycarbonate resin may contain structural units derived from other dihydroxy compounds as necessary. Details of the polycarbonate resin that can be suitably used in the present invention are described in, for example, Japanese Patent Application Laid-Open Nos. 2014-10291 and 2014-26266, and the description is incorporated herein by reference. The

The glass transition temperature of the polycarbonate resin is preferably 110 ° C. or higher and 250 ° C. or lower, more preferably 120 ° C. or higher and 230 ° C. or lower. If the glass transition temperature is excessively low, the heat resistance tends to deteriorate, there is a possibility of causing a dimensional change after film formation, and the image quality of the obtained liquid crystal display device may be lowered. If the glass transition temperature is excessively high, the molding stability at the time of film molding may deteriorate, and the transparency of the film may be impaired. The glass transition temperature is determined according to JIS K 7121 (1987).

The molecular weight of the polycarbonate resin can be represented by a reduced viscosity. The reduced viscosity is measured using a Ubbelohde viscometer at a temperature of 20.0 ° C. ± 0.1 ° C., using methylene chloride as a solvent, precisely adjusting the polycarbonate concentration to 0.6 g / dL. The lower limit of the reduced viscosity is usually preferably 0.30 dL / g, more preferably 0.35 dL / g or more. The upper limit of the reduced viscosity is usually preferably 1.20 dL / g, more preferably 1.00 dL / g, still more preferably 0.80 dL / g. If the reduced viscosity is less than the lower limit, there may be a problem that the mechanical strength of the molded product is reduced. On the other hand, if the reduced viscosity is larger than the upper limit, the fluidity at the time of molding is lowered, and there may be a problem that productivity and moldability are lowered.

The retardation film constituting the first retardation layer can be obtained, for example, by stretching a film formed from the polycarbonate resin. Any appropriate molding method can be adopted as a method of forming a film from a polycarbonate-based resin. Specific examples include compression molding methods, transfer molding methods, injection molding methods, extrusion molding methods, blow molding methods, powder molding methods, FRP molding methods, cast coating methods (for example, casting methods), calendar molding methods, and hot presses. Law. Extrusion molding or cast coating is preferred. This is because the smoothness of the resulting film can be improved and good optical uniformity can be obtained. The molding conditions can be appropriately set according to the composition and type of the resin used, the properties desired for the retardation film, and the like.

The thickness of the resin film (unstretched film) can be set to any appropriate value depending on the desired thickness of the obtained retardation film, the desired optical properties, the stretching conditions described later, and the like. The thickness is preferably 50 μm to 300 μm.

Any appropriate stretching method and stretching conditions (for example, stretching temperature, stretching ratio, stretching direction) may be employed for the stretching. Specifically, various stretching methods such as free end stretching, fixed end stretching, free end contraction, and fixed end contraction can be used singly or simultaneously or sequentially. The stretching direction can also be performed in various directions and dimensions such as a length direction, a width direction, a thickness direction, and an oblique direction.

A retardation film having the desired optical characteristics (for example, refractive index characteristics, in-plane retardation, Nz coefficient) can be obtained by appropriately selecting the stretching method and stretching conditions.

In one embodiment, the retardation film is produced by uniaxially stretching a resin film or uniaxially stretching a fixed end. As a specific example of the fixed end uniaxial stretching, there is a method of stretching in the width direction (lateral direction) while running the resin film in the longitudinal direction. The draw ratio is preferably 1.1 to 3.5 times.

In another embodiment, the retardation film can be produced by continuously stretching a long resin film obliquely in a direction at a predetermined angle with respect to the longitudinal direction. By adopting oblique stretching, a long stretched film having an orientation angle of a predetermined angle with respect to the longitudinal direction of the film (slow axis in the direction of the predetermined angle) is obtained. For example, with a polarizer Roll-to-roll is possible at the time of lamination, and the manufacturing process can be simplified. The predetermined angle may be an angle formed by the absorption axis of the first polarizer and the slow axis of the first retardation layer in the liquid crystal display device. As described above, the angle is preferably 35 ° to 55 °, more preferably 38 ° to 52 °, still more preferably 40 ° to 50 °, and particularly preferably 42 ° to 48 °. Especially preferred is 44 ° to 46 °, most preferred about 45 °.

Examples of the stretching machine used for the oblique stretching include a tenter type stretching machine capable of adding feed forces, pulling forces, or pulling forces at different speeds in the lateral and / or longitudinal directions. The tenter type stretching machine includes a horizontal uniaxial stretching machine, a simultaneous biaxial stretching machine, and the like, but any suitable stretching machine can be used as long as a long resin film can be continuously stretched obliquely.

By appropriately controlling the left and right velocities in the stretching machine, a retardation film having a desired in-plane retardation and having a slow axis in the desired direction (substantially long film) Shaped retardation film) can be obtained.

Examples of the oblique stretching method include, for example, JP-A-50-83482, JP-A-2-113920, JP-A-3-182701, JP-A-2000-9912, JP-A-2002-86554, Examples thereof include the method described in JP-A-2002-22944.

A retardation film (that is, a retardation film having an Nz coefficient of less than 1.0) that can be suitably used in an embodiment of the present invention is a heat-shrinkable film via, for example, an acrylic adhesive on one or both sides of a resin film. Can be manufactured by forming a laminated body and subjecting the laminated body to stretching as described above. A retardation film having a desired Nz coefficient can be obtained by adjusting the configuration of the heat-shrinkable film (for example, shrinkage force) and stretching conditions (for example, stretching temperature).

The stretching temperature of the film can vary depending on the in-plane retardation value and thickness desired for the retardation film, the type of resin used, the thickness of the film used, the stretching ratio, and the like. Specifically, the stretching temperature is preferably Tg-30 ° C to Tg + 30 ° C, more preferably Tg-15 ° C to Tg + 15 ° C, and most preferably Tg-10 ° C to Tg + 10 ° C. By stretching at such a temperature, a retardation film having appropriate characteristics in the present invention can be obtained. Tg is the glass transition temperature of the constituent material of the film.

A commercially available film may be used as the polycarbonate resin film. Specific examples of commercially available products include “Pure Ace WR-S”, “Pure Ace WR-W”, “Pure Ace WR-M” manufactured by Teijin Limited, and “NRF” manufactured by Nitto Denko Corporation. It is done. A commercially available film may be used as it is, and a commercially available film may be used after secondary processing (for example, stretching treatment, surface treatment) depending on the purpose.

D. Backlight light source The backlight light source 300 is included in a backlight unit (not shown). The backlight unit typically includes a light guide plate, a diffusion sheet, a prism sheet, and the like in addition to the light source. As described above, the backlight light source has a discontinuous emission spectrum. “Having a discontinuous emission spectrum” means that there is a clear peak in each wavelength region of red (R), green (G), and blue (B), and the respective peaks are clearly distinguished. That means. FIG. 2 is a diagram schematically showing an example of a discontinuous emission spectrum. As shown in FIG. 2, the emission spectrum of the backlight light source preferably has a peak P1 in the wavelength region (blue wavelength region) of 430 nm to 470 nm, more preferably 440 nm to 460 nm, preferably 530 nm to 570 nm, more preferably 540 nm. It has a peak P2 in the wavelength region of ˜560 nm (green wavelength region), and a peak P3 in the wavelength region of 630 nm to 670 nm, more preferably 640 nm to 660 nm (red wavelength region). Preferably, the wavelength λ1, the height hP1 and the half width Δλ1 of the peak P1, the wavelength λ2, the height hP2 and the half width Δλ2, the wavelength λ3 of the peak P3, the height hP3 and the half width Δλ3, the peak P1 and the peak P2 And the valley height hB2 between the peak P2 and the peak P3 satisfy the following relational expressions (1) to (3):
(Λ2−λ1) / (Δλ2 + Δλ1)> 1 (1)
(Λ3-λ2) / (Δλ3 + Δλ2)> 1 (2)
0.8 ≦ {hP2− (hB2 + hB1) / 2} / hP2 ≦ 1 (3).
(Λ2−λ1) / (Δλ2 + Δλ1) in the formula (1) is more preferably 1.01 to 2.00, and further preferably 1.10 to 1.50. (Λ3-λ2) / (Δλ3 + Δλ2) in the formula (2) is more preferably 1.01 to 2.00, and further preferably 1.10 to 1.50. {HP2- (hB2 + hB1) / 2} in the formula (3) is more preferably 0.85 to 1, and further preferably 0.9 to 1. Equation (1) means that the relationship between blue light and green light is independent as a light source without being mixed. Equation (2) means that the relationship between green light and red light is independent as a light source without being mixed. Equation (3) means that the valleys between the peaks P1, P2 and P3 are low and the peaks of blue light, green light and red light are clearly distinguished. By defining the expressions (1) to (3), there is an advantage that the color reproducibility is improved. Due to the synergistic effect of the backlight source 300 having an emission spectrum satisfying the expressions (1) to (3) and the first retardation layer 200 described above, the color reproducibility is excellent and the polarizing action is achieved. It is possible to realize a liquid crystal display device that is excellent in visibility when visually recognized through an optical member and in which color unevenness is suppressed. For example, an optical having color reproducibility and polarization action as compared with a conventional backlight light source having a light emission spectrum as shown in FIG. 3 (a white light source simply combining LEDs that emit red light, green light and blue light). Visibility and color unevenness when viewed through the member can be significantly improved.

The backlight light source has any suitable configuration capable of realizing the emission spectrum as described above. In one embodiment, the backlight source includes a red color LED, a green color LED, and a blue color LED, and the phosphor of the red color LED is activated with tetravalent manganese ions. ing. By activating the phosphor of the LED that develops red color, the overlap of red light and green light in the emission spectrum shown in FIG. 3 can be reduced, and the emission spectrum as shown in FIG. 2 can be realized. As a preferable specific example of such a red phosphor activated with tetravalent manganese ions, William M. et al. Yen and Marvin J.H. Weber CRC Publishing "INORGANIC PHOSPHORS" p. 212 (SECTION 4: PHOSPHOR DATA 4.10 Miscellaneous Oxides), Mn ⁴⁺ activated Mg fluorogermanate phosphor (2.5MgO · MgF ₂ : Mn ⁴⁺ ) and Journal of the ElectroSocial A: M ¹ ₂ M ² F ₆ : Mn ⁴⁺ (M ¹ = Li, Na, K, Rb, Cs; M ² = Si, Ge, Sn, Ti, Zr, exemplified in SCIENCE AND TECHNOLOGY, July 1973, p942 ) Phosphors. A backlight light source using such a red phosphor is described in, for example, Japanese Patent Application Laid-Open No. 2015-52648. Further, a backlight light source having a general configuration including a red color LED, a green color LED, and a blue color LED is described in, for example, Japanese Patent Application Laid-Open No. 2012-256014. The descriptions in these publications are incorporated herein by reference.

In another embodiment, the backlight source includes a blue color LED and a wavelength conversion layer including quantum dots. With such a configuration, part of the blue light emitted from the LED is converted into red light and green light by the wavelength conversion layer, and part of the blue light is emitted as blue light as it is. As a result, white light can be realized. Furthermore, by appropriately configuring the wavelength conversion layer, an emission spectrum (emission spectrum as shown in FIG. 2) in which the peaks of red light, green light, and blue light are clear and the overlap of each color light is small is realized. be able to.

The wavelength conversion layer typically includes a matrix and quantum dots dispersed in the matrix. Any appropriate material can be used as a material constituting the matrix (hereinafter also referred to as matrix material). Examples of such materials include resins, organic oxides, and inorganic oxides. The matrix material preferably has low oxygen permeability and moisture permeability, high light stability and chemical stability, a predetermined refractive index, excellent transparency, and / or Have excellent dispersibility with respect to quantum dots. Considering these comprehensively, the matrix material is preferably a resin. The resin may be a thermoplastic resin, a thermosetting resin, or an active energy ray curable resin (for example, an electron beam curable resin, an ultraviolet curable resin, or a visible light curable resin). May be. A thermosetting resin or an ultraviolet curable resin is preferable, and a thermosetting resin is more preferable. The resins may be used alone or in combination (for example, blend, copolymerization).

Quantum dots can control the wavelength conversion characteristics of the wavelength conversion layer. Specifically, a wavelength conversion layer that realizes light having a desired emission center wavelength can be formed by appropriately combining quantum dots having different emission center wavelengths. The emission center wavelength of the quantum dot can be adjusted by the material and / or composition, particle size, shape, etc. of the quantum dot. Examples of the quantum dot include a quantum dot having an emission center wavelength in a wavelength band in the range of 600 nm to 680 nm (hereinafter referred to as quantum dot A), and a quantum dot having an emission center wavelength in a wavelength band in the range of 500 nm to 600 nm (hereinafter referred to as “dots”). Quantum dots B) and quantum dots having an emission center wavelength in the wavelength band of 400 nm to 500 nm (hereinafter, quantum dots C) are known. The quantum dots A are excited by excitation light (in the present invention, light from a backlight light source) to emit red light, the quantum dots B emit green light, and the quantum dots C emit blue light. By appropriately combining these, when light having a predetermined wavelength (light from the backlight light source) enters and passes through the wavelength conversion layer, light having a light emission center wavelength in a desired wavelength band can be realized.

The quantum dots can be composed of any suitable material. The quantum dots are preferably composed of an inorganic material, more preferably an inorganic conductor material or an inorganic semiconductor material. Semiconductor materials include, for example, II-VI, III-V, IV-VI, and IV semiconductors. Specific examples include Si, Ge, Sn, Se, Te, B, C (including diamond), P, BN, BP, BAs, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, ZnO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdSeZn, CdTe, HgS, HgSe, HgTe, BeS, BeSe, BeTe, MgS, MgSe, GeS, GeSe, Sn, Te, SnS PbO, PbS, PbSe, PbTe, CuF, CuCl, CuBr, CuI, Si ₃ N ₄ , Ge ₃ N ₄ , Al ₂ O ₃ , (Al, Ga, In) ₂ (S, Se, Te) ₃ , Al ₂ CO is mentioned. These may be used alone or in combination of two or more. The quantum dot may contain a p-type dopant or an n-type dopant.

Any appropriate size can be adopted as the size of the quantum dot depending on the desired emission wavelength. The size of the quantum dots is preferably 1 nm to 10 nm, more preferably 2 nm to 8 nm. If the size of the quantum dot is in such a range, each of green and red emits sharp light and high color rendering can be realized. For example, green light can be emitted with a quantum dot size of about 7 nm, and red light can be emitted with about 3 nm. The size of the quantum dot is, for example, an average particle diameter when the quantum dot is a true sphere, and is a dimension along the minimum axis in the shape when the quantum dot is other than that. As the shape of the quantum dot, any appropriate shape can be adopted depending on the purpose. Specific examples include a true sphere shape, a flake shape, a plate shape, an elliptic sphere shape, and an indefinite shape.

Quantum dots can be blended in a proportion of preferably 1 to 50 parts by weight, more preferably 2 to 30 parts by weight, with respect to 100 parts by weight of the matrix material. When the blending amount of the quantum dots is in such a range, a liquid crystal display device excellent in hue balance of all RGB can be realized.

Details of the quantum dots are disclosed in, for example, JP2012-169271A, JP2015-102857A, JP2015-65158A, JP2013-544018A, JP2013-544018A, Special Table. No. 2010-533976, and the descriptions of these publications are incorporated herein by reference. A commercial item may be used for the quantum dot.

The thickness of the wavelength conversion layer is preferably 1 μm to 500 μm, more preferably 100 μm to 400 μm. When the thickness of the wavelength conversion layer is in such a range, conversion efficiency and durability can be excellent.

The wavelength conversion layer is disposed as a film on the emission side of the LED (light source) in the backlight unit.

E. Second Retardation Layer As described above, the second retardation layer 400 has a relationship in which the refractive index characteristic is nz> nx ≧ ny. The thickness direction retardation Rth (550) of the second retardation layer is preferably −260 nm to −10 nm, more preferably −230 nm to −15 nm, and still more preferably −215 nm to −20 nm. By providing the second retardation layer having such optical characteristics, coloring when viewed from an oblique direction through an optical member having a polarizing action (for example, polarized sunglasses) is remarkably improved, and as a result A liquid crystal display device having very excellent viewing angle characteristics can be obtained.

In one embodiment, the second retardation layer has a refractive index of nx = ny. In another embodiment, the second retardation layer exhibits a relationship in which the refractive index is nx> ny. Therefore, the second retardation layer may have a slow axis. In this case, the slow axis of the second retardation layer is substantially orthogonal or parallel to the absorption axis of the first polarizer 20. The in-plane retardation Re (550) of the second retardation layer is preferably 10 nm to 150 nm, more preferably 10 nm to 80 nm.

The second retardation layer can be formed of any appropriate material. A liquid crystal layer fixed in homeotropic alignment is preferable. The liquid crystal material (liquid crystal compound) that can be homeotropically aligned may be a liquid crystal monomer or a liquid crystal polymer. Specific examples of the liquid crystal compound and the method for forming the liquid crystal layer include the liquid crystal compounds and methods described in JP-A-2002-333642, [0020] to [0042]. In this case, the thickness is preferably 0.1 μm to 5 μm, more preferably 0.2 μm to 3 μm.

As another preferred specific example, the second retardation layer may be a retardation film formed of a fumaric acid diester resin described in JP 2012-32784 A. In this case, the thickness is preferably 5 μm to 80 μm, more preferably 10 μm to 50 μm.

F. Conductive Layer The conductive layer (not shown) is typically transparent (ie, the conductive layer is a transparent conductive layer). By forming a conductive layer between the first polarizer 20 and the liquid crystal cell 10, the liquid crystal display device can function as a so-called inner touch panel type input display device.

The conductive layer may be used alone as a constituent layer of the liquid crystal display device, or may be provided to the liquid crystal display device as a laminate with the base material (conductive layer with base material). In the case where the conductive layer is formed by itself, the conductive layer can be transferred from the base material on which the conductive layer is formed to a predetermined position of the liquid crystal display device.

The conductive layer can be patterned as needed. By conducting the patterning, a conductive portion and an insulating portion can be formed. As a result, an electrode can be formed. The electrode can function as a touch sensor electrode that senses contact with the touch panel. The pattern shape is preferably a pattern that works well as a touch panel (for example, a capacitive touch panel). Specific examples include the patterns described in JP2011-511357A, JP2010-164938A, JP2008-310550A, JP2003-511799A, and JP2010-541109A. It is done.

The total light transmittance of the conductive layer is preferably 80% or more, more preferably 85% or more, and further preferably 90% or more. For example, if a conductive nanowire described later is used, a transparent conductive layer having openings can be formed, and a transparent conductive layer having a high light transmittance can be obtained.

The density of the conductive layer is preferably 1.0 g / cm ³ to 10.5 g / cm ³ , more preferably 1.3 g / cm ³ to 3.0 g / cm ³ .

The surface resistance value of the conductive layer is preferably 0.1Ω / □ to 1000Ω / □, more preferably 0.5Ω / □ to 500Ω / □, and further preferably 1Ω / □ to 250Ω / □.

Typical examples of the conductive layer include a conductive layer containing a metal oxide, a conductive layer containing a conductive nanowire, and a conductive layer containing a metal mesh. A conductive layer including conductive nanowires or a conductive layer including a metal mesh is preferable. This is because it is excellent in bending resistance and it is difficult to lose conductivity even when bent, so that a conductive layer that can be bent well can be formed. As a result, the liquid crystal display device can be configured to be bendable.

A conductive layer containing a metal oxide is formed on any appropriate base material by any appropriate film formation method (for example, vacuum deposition method, sputtering method, CVD method, ion plating method, spray method, etc.). It can be formed by forming an oxide film. Examples of the metal oxide include indium oxide, tin oxide, zinc oxide, indium-tin composite oxide, tin-antimony composite oxide, zinc-aluminum composite oxide, and indium-zinc composite oxide. Of these, indium-tin composite oxide (ITO) is preferable.

The conductive layer containing conductive nanowires is formed by applying a dispersion liquid (conductive nanowire dispersion liquid) in which conductive nanowires are dispersed in a solvent onto any appropriate substrate, and then drying the coating layer. be able to. Any appropriate conductive nanowire can be used as the conductive nanowire as long as the effects of the present invention can be obtained. The conductive nanowire refers to a conductive substance having a needle shape or a thread shape and a diameter of nanometer size. The conductive nanowire may be linear or curved. As described above, the conductive layer including the conductive nanowire has excellent bending resistance. In addition, a conductive layer containing conductive nanowires can form a good electrical conduction path even with a small amount of conductive nanowires by forming gaps between conductive nanowires and forming a mesh. Thus, a conductive layer having a small electric resistance can be obtained. Further, when the conductive nanowires have a mesh shape, openings can be formed in the mesh gaps to obtain a conductive layer having a high light transmittance. Examples of the conductive nanowire include metal nanowires made of metal, conductive nanowires including carbon nanotubes, and the like.

The ratio between the thickness d and the length L of the conductive nanowire (aspect ratio: L / d) is preferably 10 to 100,000, more preferably 50 to 100,000, still more preferably 100 to 10,000. When conductive nanowires having a large aspect ratio are used in this way, the conductive nanowires can cross well and high conductivity can be expressed by a small amount of conductive nanowires. As a result, a conductive layer having a high light transmittance can be obtained. In this specification, “the thickness of the conductive nanowire” means the diameter when the cross section of the conductive nanowire is circular, and the short diameter when the cross section of the conductive nanowire is elliptical. If it is square, it means the longest diagonal. The thickness and length of the conductive nanowire can be confirmed by a scanning electron microscope or a transmission electron microscope.

The thickness of the conductive nanowire is preferably less than 500 nm, more preferably less than 200 nm, still more preferably 1 nm to 100 nm, and particularly preferably 1 nm to 50 nm. If it is such a range, a conductive layer with high light transmittance can be formed. The length of the conductive nanowire is preferably 2.5 μm to 1000 μm, more preferably 10 μm to 500 μm, and further preferably 20 μm to 100 μm. Within such a range, a conductive layer having high conductivity can be obtained.

As the metal constituting the conductive nanowire (metal nanowire), any appropriate metal can be used as long as it is a highly conductive metal. The metal nanowire is preferably composed of one or more metals selected from the group consisting of gold, platinum, silver, and copper. Among these, silver, copper, or gold is preferable from the viewpoint of conductivity, and silver is more preferable. Alternatively, a material obtained by performing a plating process (for example, a gold plating process) on the metal may be used.

Any appropriate carbon nanotube can be used as the carbon nanotube. For example, so-called multi-walled carbon nanotubes, double-walled carbon nanotubes, single-walled carbon nanotubes and the like are used. Among these, single-walled carbon nanotubes are preferably used because of their high conductivity.

As the metal mesh, any appropriate metal mesh can be used as long as the effects of the present invention can be obtained. For example, it is possible to use a metal wiring layer provided on a film substrate that is patterned in a mesh pattern.

Details of the conductive nanowire and the metal mesh are described in, for example, Japanese Patent Application Laid-Open Nos. 2014-113705 and 2014-219667. The description of the publication is incorporated herein by reference.

The thickness of the conductive layer is preferably 0.01 μm to 10 μm, more preferably 0.05 μm to 3 μm, and still more preferably 0.1 μm to 1 μm. If it is such a range, the conductive layer excellent in electroconductivity and light transmittance can be obtained. When the conductive layer contains a metal oxide, the thickness of the conductive layer is preferably 0.01 μm to 0.05 μm.

G. Adhesive Layer or Adhesive Layer Any appropriate pressure-sensitive adhesive layer or adhesive layer is used for laminating each layer and the optical member constituting the liquid crystal display device of the present invention. The pressure-sensitive adhesive layer is typically formed of an acrylic pressure-sensitive adhesive. The adhesive layer is typically formed of a polyvinyl alcohol-based adhesive.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. In addition, the measuring method of each characteristic is as follows. Unless otherwise specified, “parts” and “%” in the examples are based on weight.

(1) Thickness The thickness was measured using a dial gauge (manufactured by PEACOCK, product name “DG-205”, dial gauge stand (product name “pds-2”)).
(2) Retardation A 50 mm × 50 mm sample was cut out from each retardation film and the liquid crystal solidified layer to obtain a measurement sample, which was measured using Axoscan manufactured by Axometrics. The measurement wavelength was 450 nm, 550 nm, and the measurement temperature was 23 ° C.
Moreover, the average refractive index was measured using an Abbe refractometer manufactured by Atago Co., Ltd., and the refractive indexes nx, ny, and nz were calculated from the obtained retardation values.
(3) Water absorption rate Measured according to “Test method for water absorption rate and boiling water absorption rate of plastic” described in JIS K 7209. The size of the test piece was a square with a side of 50 mm, and was obtained by immersing the test piece in water at a water temperature of 25 ° C. for 24 hours and then measuring the weight change before and after the immersion. The unit is%.
(4) Backlight spectrum measurement A white image was displayed on the liquid crystal display device obtained in each example and each comparative example, and an emission spectrum was measured using SR-UL1R manufactured by Topcon. With respect to the obtained emission spectrum, the wavelength λ1, wavelength λ2, wavelength λ3, height hP1, height hP2, height hP3, height hB1, height hB2, half width Δλ1, half width Δλ2, and half shown in FIG. Based on the value width Δλ3, values represented by the following formulas (4), (5), and (6) were obtained. Since the spectrum of the display light when the white image is displayed on the liquid crystal display device is substantially equal to the emission spectrum of the backlight light source, the spectrum of the display light when the white image is displayed is the emission spectrum of the backlight light source. It was.
(Λ2-λ1) / (Δλ2 + Δλ1) (4)
(Λ3-λ2) / (Δλ3 + Δλ2) (5)
{HP2- (hB2 + hB1) / 2} / hP2 (6)
(5) Visibility evaluation A white image was displayed on the liquid crystal display devices obtained in each example and each comparative example, and the visibility when the image was observed through polarized sunglasses was evaluated according to the following criteria.
Good: Coloring and rainbow unevenness did not occur. Coloring occurred.

<Example 1>
(Preparation of retardation film A constituting the first retardation layer)
Polymerization was carried out using a batch polymerization apparatus comprising two vertical reactors equipped with a stirring blade and a reflux condenser controlled at 100 ° C. 9,9- [4- (2-hydroxyethoxy) phenyl] fluorene (BHEPF), isosorbide (ISB), diethylene glycol (DEG), diphenyl carbonate (DPC), and magnesium acetate tetrahydrate in a molar ratio of BHEPF / ISB / DEG / DPC / magnesium acetate = 0.348 / 0.490 / 0.162 / 1.005 / 1.00 × 10 ⁻⁵ . After sufficiently replacing the inside of the reactor with nitrogen (oxygen concentration 0.0005 to 0.001 vol%), heating was performed with a heating medium, and stirring was started when the internal temperature reached 100 ° C. After 40 minutes from the start of temperature increase, the internal temperature was reached to 220 ° C., and control was performed so as to maintain this temperature. The phenol vapor produced as a by-product with the polymerization reaction was led to a reflux condenser at 100 ° C., and a monomer component contained in a small amount in the phenol vapor was returned to the reactor, and the phenol vapor not condensed was led to a condenser at 45 ° C. and recovered.
Nitrogen was introduced into the first reactor and the pressure was once restored to atmospheric pressure, and then the oligomerized reaction liquid in the first reactor was transferred to the second reactor. Subsequently, the temperature increase and pressure reduction in the second reactor were started, and the internal temperature was 240 ° C. and the pressure was 0.2 kPa in 50 minutes. Thereafter, polymerization was allowed to proceed until a predetermined stirring power was obtained. When a predetermined power is reached, nitrogen is introduced into the reactor, the pressure is restored, the reaction solution is withdrawn in the form of a strand, pelletized with a rotary cutter, and BHEPF / ISB / DEG = 34.8 / 49.0 / A polycarbonate resin having a copolymer composition of 16.2 [mol%] was obtained. This polycarbonate resin had a reduced viscosity of 0.430 dL / g and a glass transition temperature of 128 ° C. The obtained polycarbonate resin was vacuum-dried at 80 ° C. for 5 hours, and then a single-screw extruder (manufactured by Isuzu Chemical Industries, screw diameter 25 mm, cylinder set temperature: 220 ° C.), T-die (width 900 mm, set temperature: 220). ° C), a chill roll (set temperature: 125 ° C), and a film forming apparatus equipped with a winder, a polycarbonate resin film having a thickness of 70 µm was produced. The polycarbonate resin film obtained had a water absorption rate of 1.2%. The obtained polycarbonate resin film was uniaxially stretched 2.0 times at 133 ° C. to obtain a retardation film A (thickness 50 μm). Re (550) of the obtained retardation film A was 140 nm, Rth (550) was 140 nm, and Re (450) / Re (550) was 0.89.

(Production of polarizer)
An A-PET (amorphous-polyethylene terephthalate) film (manufactured by Mitsubishi Plastics Co., Ltd., trade name: Novaclear SH046 200 μm) was prepared as a base material, and the surface was subjected to corona treatment (58 W / m ² / min). On the other hand, 1 wt% of acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name: Gohsephimer Z200 (polymerization degree 1200, saponification degree 99.0% or more, acetoacetyl modification degree 4.6%)) is added. Prepared PVA (polymerization degree 4200, saponification degree 99.2%), coated on a substrate so that the film thickness after drying becomes 12 μm, and dried for 10 minutes by hot air drying in an atmosphere of 60 ° C. And the laminated body which provided the layer of the PVA-type resin on the base material was produced.
Next, the laminate was first stretched 2.0 times in the MD direction at 130 ° C. in air to produce a stretched laminate. Next, a step of insolubilizing the PVA layer in which the PVA molecules contained in the stretched laminate were oriented was performed by immersing the stretched laminate in a boric acid insolubilized aqueous solution having a liquid temperature of 30 ° C. for 30 seconds. The boric acid aqueous solution for insolubilization in this step contains 3 parts by weight of boric acid content with respect to 100 parts by weight of water. A colored laminate was produced by dyeing the stretched laminate after the insolubilization step. In this colored laminate, iodine is adsorbed on the PVA layer contained in the stretched laminate by immersing the stretched laminate in a dyeing solution. The staining solution contains iodine and potassium iodide, the temperature of the staining solution is 30 ° C., water is used as a solvent, the iodine concentration is in the range of 0.08 to 0.25 wt%, and the potassium iodide concentration Was in the range of 0.56 to 1.75% by weight. The ratio of iodine to potassium iodide concentration was 1: 7. As dyeing conditions, the iodine concentration and the immersion time were set so that the single transmittance of the PVA resin layer constituting the polarizer was 40.9%.
Next, the colored laminate was immersed in an aqueous boric acid solution for crosslinking at 30 ° C. for 60 seconds to perform a step of crosslinking the PVA molecules of the PVA layer on which iodine was adsorbed. The boric acid aqueous solution for crosslinking used in this crosslinking step had a boric acid content of 3 parts by weight with respect to 100 parts by weight of water and a potassium iodide content of 3 parts by weight with respect to 100 parts by weight of water. Is. Further, the obtained colored laminate is stretched 2.7 times in a boric acid aqueous solution at a stretching temperature of 70 ° C. in the same direction as the previous stretching in air, whereby the final stretching ratio is increased. The film was stretched by 5.4 times to obtain an optical film laminate including the test polarizer. The boric acid aqueous solution used in this stretching step has a boric acid content of 4.0 parts by weight with respect to 100 parts by weight of water and a potassium iodide content of 5 parts by weight with respect to 100 parts by weight of water. It is. The obtained optical film laminate was taken out from the boric acid aqueous solution, and the boric acid adhering to the surface of the PVA layer was washed with an aqueous solution containing 4 parts by weight of potassium iodide with respect to 100 parts by weight of water. The washed optical film laminate was dried by a drying process using hot air at 60 ° C. to obtain a polarizer having a thickness of 5 μm laminated on the PET film.

(Preparation of polarizing plate with retardation layer)
In the polarizer produced as described above, the retardation film A is attached to the surface opposite to the PET with a UV curable adhesive on the 5 μm thick polarizer laminated on the PET film. Bonding was performed so that the angle between the slow axis and the absorption axis of the polarizer was substantially 45 °. Furthermore, the PET film was peeled from this laminate to obtain a polarizing plate with a retardation layer.

(Production of liquid crystal display device)
Take out the liquid crystal panel from the liquid crystal display device of the smartphone (SONY Xperia Z4: the backlight emission spectrum is discontinuous) equipped with an IPS liquid crystal display device, remove the polarizing plate placed on the viewing side of the liquid crystal cell, The glass surface of the liquid crystal cell was washed. Subsequently, the surface on the viewing side of the liquid crystal cell is the surface on the polarizer side of the polarizing plate with the retardation plate so that the absorption axis of the polarizer is orthogonal to the initial alignment direction of the liquid crystal cell (first The angle between the slow axis of the retardation layer and the long side of the liquid crystal panel is 45 °, and the angle between the absorption axis of the polarizer and the long side of the liquid crystal panel is 0 °), an acrylic adhesive A liquid crystal panel was obtained by laminating via an agent (thickness 20 μm). The backlight unit of the smartphone was attached to the liquid crystal panel on which the polarizing plate with a retardation plate was laminated to obtain the liquid crystal display device of this example. A white image was displayed on the liquid crystal display device, and the visibility was evaluated through polarized sunglasses in a white image state. The evaluation results are shown in Table 1.

<Example 2>
(Preparation of retardation film B constituting the first retardation layer)
A polycarbonate resin (10 kg) obtained in the same manner as in Example 1 was dissolved in methylene chloride (73 kg) to prepare a birefringent layer forming material. Next, the birefringent layer-forming material was directly coated on a shrinkable film (longitudinal uniaxially stretched polypropylene film, trade name “Noblen” manufactured by Tokyo Ink Co., Ltd.), and the coating film was dried at 30 ° C. at 5 ° C. The laminate was dried at 80 ° C. for 5 minutes for 5 minutes to form a shrinkable film / birefringent layer laminate. The obtained laminate is stretched at a stretching temperature of 155 ° C. at a stretching temperature of 155 ° C. by stretching the shrinkage ratio to 0.80 in the MD direction and 1.3 times in the TD direction, thereby forming the retardation film B on the shrinkable film. Formed. Next, the retardation film B was peeled from the shrinkable film.
Thus, a retardation film B (thickness 60 μm) was obtained. Re (550) of the obtained retardation film B was 140 nm, Rth (550) was 70 nm, and Re (450) / Re (550) was 0.89. The slow axis direction of the retardation film B was 90 ° with respect to the longitudinal direction.

(Preparation of polarizing plate with retardation layer and liquid crystal display device)
A polarizing plate with a retardation layer was prepared in the same manner as in Example 1 except that the retardation film B was used in place of the retardation film A, and the polarizing plate with a retardation layer was used. In the same manner as in Example 1, a liquid crystal display device was produced. A white image was displayed on the liquid crystal display device, and the visibility was evaluated through polarized sunglasses in a white image state. The evaluation results are shown in Table 1.

<Example 3>
(Preparation of the liquid crystal solidified layer constituting the second retardation layer)
20 parts by weight of a side chain type liquid crystal polymer represented by the following chemical formula (I) (numbers 65 and 35 in the formula indicate mol% of the monomer units and are represented by block polymer for convenience: weight average molecular weight 5000), Dissolve 80 parts by weight of a polymerizable liquid crystal exhibiting a nematic liquid crystal phase (manufactured by BASF: trade name: Palicolor LC242) and 5 parts by weight of a photopolymerization initiator (trade name: Irgacure 907, manufactured by Ciba Specialty Chemicals) in 200 parts by weight of cyclopentanone. Thus, a liquid crystal coating solution was prepared. And after apply | coating the said coating liquid to a base film (norbornene-type resin film: Nippon Zeon Co., Ltd. make, brand name "ZEONEX") with a bar coater, a liquid crystal is dried by heating at 80 degreeC for 4 minutes. Oriented. The liquid crystal layer was irradiated with ultraviolet rays to cure the liquid crystal layer, thereby forming a liquid crystal solidified layer (thickness: 1.10 μm) serving as a second retardation layer on the base film. This liquid crystal solidified layer had Re (550) of 0 nm, Rth (550) of −100 nm, and exhibited a refractive index characteristic of nz> nx = ny.

(Preparation of polarizing plate with retardation layer)
For the laminate of the PET film and the polarizer obtained in the same manner as in Example 1, the liquid crystal solidified layer was formed on the surface opposite to the PET film via a UV curable adhesive, and the base film The base film was peeled off when removing the film and the polarizer was bonded so that the absorption axis of the polarizer was substantially parallel. Further, the base film is removed, and the retardation film A produced in the same manner as in Example 1 is provided on the opposite side of the liquid crystal solidified layer from the polarizer with a UV curable adhesive as its slow axis. Bonding was performed so that the angle with the absorption axis of the polarizer was substantially 45 °. Furthermore, after peeling the PET film from this laminate, an acrylic protective film or a retardation layer as needed was bonded via a UV curable adhesive to produce a polarizing plate with a retardation layer.

(Production of liquid crystal display device)
A liquid crystal display device was produced in the same manner as in Example 1 except that the polarizing plate with a retardation layer was used and a smartphone having a different backlight was used. A white image was displayed on the liquid crystal display device, and the visibility was evaluated through polarized sunglasses in a white image state. The evaluation results are shown in Table 1.

<Example 4>
(Preparation of retardation film C constituting the first retardation layer)
The polycarbonate resin obtained in the same manner as in Example 1 was vacuum-dried at 80 ° C. for 5 hours, and then a single-screw extruder (manufactured by Isuzu Chemical Industries, screw diameter 25 mm, cylinder setting temperature: 220 ° C.), T-die ( A polycarbonate resin film having a thickness of 130 μm was prepared using a film forming apparatus equipped with a width of 900 mm, a set temperature: 220 ° C., a chill roll (set temperature: 125 ° C.), and a winder. The polycarbonate resin film obtained had a water absorption rate of 1.2%.
The polycarbonate resin film was obliquely stretched by a method according to Example 1 of JP 2014-194383 A to obtain a retardation film C.
The specific production procedure of the retardation film C is as follows: A polycarbonate resin film (thickness 130 μm, width 765 mm) was preheated to 142 ° C. in the preheating zone of the stretching apparatus. In the preheating zone, the clip pitch of the left and right clips was 125 mm. Next, as soon as the film entered the first oblique stretching zone C1, the clip pitch of the right clip began to increase and increased from 125 mm to 177.5 mm in the first oblique stretching zone C1. The clip pitch change rate was 1.42. In the first oblique stretching zone C1, the clip pitch of the left clip started to decrease and decreased from 125 mm to 90 mm in the first oblique stretching zone C1. The clip pitch change rate was 0.72. Furthermore, as soon as the film entered the second oblique stretching zone C2, the clip pitch of the left clip started to increase and increased from 90 mm to 177.5 mm in the second oblique stretching zone C2. On the other hand, the clip pitch of the right clip was maintained at 177.5 mm in the second oblique stretching zone C2. Simultaneously with the oblique stretching, stretching in the width direction was performed 1.9 times. The oblique stretching was performed at 135 ° C. Next, MD shrinkage treatment was performed in the shrinkage zone. Specifically, the clip pitches of the left clip and right clip were both reduced from 177.5 mm to 165 mm. The shrinkage rate in the MD shrinkage treatment was 7.0%.
Thus, a retardation film C (thickness 40 μm) was obtained. Re (550) of the obtained retardation film C was 140 nm, Rth (550) was 168 nm, and Re (450) / Re (550) was 0.89. The slow axis direction of the retardation film C was 45 ° with respect to the longitudinal direction.

(Preparation of polarizing plate with retardation layer and liquid crystal display device)
A polarizing plate with a retardation layer was produced in the same manner as in Example 1 except that the retardation film C was used in place of the retardation film A, and the polarizing plate with a retardation layer was used. In the same manner as in Example 1, a liquid crystal display device was produced. A white image was displayed on the liquid crystal display device, and the visibility was evaluated through polarized sunglasses in a white image state. The evaluation results are shown in Table 1.

<Comparative Example 1>
(Preparation of retardation film D constituting first retardation layer)
A biaxially stretched polypropylene film (trade name “Trephan” (thickness 60 μm) manufactured by Toray, Inc.) is placed on both sides of a commercially available Arton film (manufactured by JSR, thickness 70 μm) via an acrylic adhesive layer (thickness 15 μm). Pasted together. Thereafter, the longitudinal direction of the film was held with a roll stretching machine, and the film was stretched 1.45 times in an air circulation type thermostatic oven at 147 ° C. to obtain a retardation film D. Re (550) of the obtained retardation film D was 140 nm, Rth (550) was 70 nm, and Re (450) / Re (550) was 1.00.

(Preparation of polarizing plate with retardation layer and liquid crystal display device)
A polarizing plate with a retardation layer was produced in the same manner as in Example 1 except that the retardation film D was used in place of the retardation film A, and the polarizing plate with a retardation layer was used. In the same manner as in Example 1, a liquid crystal display device was produced. A white image was displayed on the liquid crystal display device, and the visibility was evaluated through polarized sunglasses in a white image state. The evaluation results are shown in Table 1.

<Comparative Example 2>
(Preparation of retardation film E constituting the first retardation layer)
A commercially available ARTON film (manufactured by JSR Co., Ltd., thickness 100 μm) is stretched 1.8 times in a 147 ° C. air-circulating constant temperature oven while maintaining the longitudinal direction of the film with a roll stretching machine to obtain a retardation film E. It was. Re (550) of the obtained retardation film E was 140 nm, Rth (550) was 140 nm, and Re (450) / Re (550) was 1.00.

(Preparation of polarizing plate with retardation layer)
A polarizing plate with a retardation layer was produced in the same manner as in Example 1 except that the retardation film E was used.

(Production of liquid crystal display device)
Take out the liquid crystal panel from the liquid crystal display device of the smartphone (Apple 5 iPhone 5: backlight emission spectrum is continuous) equipped with the IPS liquid crystal display device, remove the polarizing plate placed on the viewing side of the liquid crystal cell, The glass surface of the liquid crystal cell was washed. Subsequently, the surface on the viewing side of the liquid crystal cell is the surface on the polarizer side of the polarizing plate with retardation plate, and the acrylic system is such that the absorption axis of the polarizer is orthogonal to the initial alignment direction of the liquid crystal cell. It laminated | stacked through the adhesive (thickness 20 micrometers), and obtained the liquid crystal panel. The liquid crystal panel on which the polarizing plate with a retardation plate was laminated was attached to the smartphone to obtain the liquid crystal display device of this example. A white image was displayed on the liquid crystal display device, and the visibility was evaluated through polarized sunglasses in a white image state. The evaluation results are shown in Table 1.

<Comparative Example 3>
(Preparation of retardation film F constituting the first retardation layer)
Phosgene as the carbonate precursor, (A) 2,2-bis (4-hydroxyphenyl) propane as the aromatic dihydric phenol component, and (B) 1,1-bis (4-hydroxyphenyl) -3,3,5- Using trimethylcyclohexane, a repeating unit of the following chemical formulas (II) and (III) having a weight ratio of (A) :( B) of 4: 6 and a weight average molecular weight (Mw) of 60,000 according to a conventional method Polycarbonate resin [number average molecular weight (Mn) = 33,000, Mw / Mn = 1.78] was obtained. 70 parts by weight of the above polycarbonate resin and 30 parts by weight of a styrene resin having a weight average molecular weight (Mw) of 1,300 [number average molecular weight (Mn) = 716, Mw / Mn = 1.78] (Sanyo Kasei Heimer SB75) Was added to 300 parts by weight of dichloromethane and stirred and mixed at room temperature for 4 hours to obtain a transparent solution. This solution was cast on a glass plate and allowed to stand at room temperature for 15 minutes, then peeled off from the glass plate, dried in an oven at 80 ° C. for 10 minutes, and then at 120 ° C. for 20 minutes, and had a thickness of 40 μm and a glass transition temperature (Tg ) Obtained a polymer film of 140 ° C. The polymer film obtained had a light transmittance of 93% at a wavelength of 590 nm. The in-plane retardation value of the polymer film: Re (590) was 5.0 nm, and the retardation value in the thickness direction: Rth (590) was 12.0 nm. The average refractive index was 1.576.
The obtained polymer film was uniaxially stretched 1.5 times in an air circulation type thermostatic oven at 150 ° C. to obtain a retardation film F. Re (550) of the obtained retardation film F was 140 nm, Rth (550) was 140 nm, and Re (450) / Re (550) was 1.06.

(Preparation of polarizing plate with retardation layer and liquid crystal display device)
A polarizing plate with a retardation layer was produced in the same manner as in Example 1 except that the retardation film F was used in place of the retardation film A, and the polarizing plate with a retardation layer was used in the same manner as in Example 1. In the same manner as in Example 1, a liquid crystal display device was produced. A white image was displayed on the liquid crystal display device, and the visibility was evaluated through polarized sunglasses in a white image state. The evaluation results are shown in Table 1.

The liquid crystal display device of the present invention includes portable information terminals (PDAs), mobile phones, watches, digital cameras, portable game devices such as portable game machines, OA devices such as personal computer monitors, notebook computers, copy machines, video cameras, liquid crystal televisions, Household electrical equipment such as microwave ovens, back monitors, car navigation system monitors, in-car equipment such as car audio, display equipment such as commercial store information monitors, security equipment such as monitoring monitors, nursing care monitors, medical care It can be suitably used for various uses such as nursing care and medical equipment such as monitors for medical use.

DESCRIPTION OF SYMBOLS 10 Liquid crystal cell 11 Board | substrate 12 Board | substrate 13 Liquid crystal layer 20 1st polarizer 30 2nd polarizer 100 Liquid crystal panel 200 Phase difference layer (1st phase difference layer)
300 Backlight source 400 Another retardation layer (second retardation layer)
500 Liquid crystal display device

Claims

A liquid crystal panel including a liquid crystal cell, a first polarizer disposed on the viewing side of the liquid crystal cell, and a second polarizer disposed on the back side of the liquid crystal cell;
A retardation layer disposed on the viewing side of the liquid crystal panel;
A backlight source that illuminates the liquid crystal panel from the back side;
The in-plane retardation Re (550) of the retardation layer is 100 nm to 180 nm, and satisfies the relationship of Re (450) <Re (550) <Re (650),
The angle formed by the slow axis of the retardation layer and the long side of the liquid crystal panel is 35 ° to 55 °,
The backlight source has a discontinuous emission spectrum;
Liquid crystal display device.
The emission spectrum of the backlight source has a peak P1 in a wavelength region of 430 nm to 470 nm, a peak P2 in a wavelength region of 530 nm to 570 nm, and a peak P3 in a wavelength region of 630 nm to 670 nm,
The wavelength of the peak P1 is λ1, the height is hP1 and the half width is Δλ1, the wavelength of the peak P2 is λ2, the height is hP2 and the half width is Δλ2, the wavelength of the peak P3 is λ3, the height is hP3 and the half width is Δλ3. When the height of the valley between the peak P1 and the peak P2 is hB1, and the height of the valley between the peak P2 and the peak P3 is hB2, these are expressed by the following relational expressions (1) to (3). The liquid crystal display device according to claim 1, wherein:
(Λ2−λ1) / (Δλ2 + Δλ1)> 1 (1)
(Λ3-λ2) / (Δλ3 + Δλ2)> 1 (2)
0.8 ≦ {hP2− (hB2 + hB1) / 2} / hP2 ≦ 1 (3).
3. The liquid crystal display device according to claim 1, wherein the refractive index ellipsoid of the retardation layer shows a relationship of nx> nz> ny and the Nz coefficient is 0.2 to 0.8.
4. The liquid crystal display device according to claim 1, further comprising: another retardation layer having a refractive index ellipsoid showing a relationship of nz> nx ≧ ny between the liquid crystal panel and the retardation layer. 5. .
The backlight light source includes an LED that develops red, an LED that develops green, and an LED that develops blue. The phosphor of the LED that develops red is activated with tetravalent manganese ions. 5. A liquid crystal display device according to any one of 1 to 4.
The liquid crystal display device according to any one of claims 1 to 4, wherein the backlight light source includes a blue color LED and a wavelength conversion layer including quantum dots.
The absorption axis of the first polarizer is substantially perpendicular or parallel to the long side of the liquid crystal panel, and the absorption axis of the second polarizer is substantially parallel to the long side of the liquid crystal panel. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is orthogonal or parallel, and the absorption axis of the first polarizer and the absorption axis of the second polarizer are substantially orthogonal.