KR20060101346A - Optical compensation film, polarizing plate and liquid crystal display - Google Patents

Abstract

Provided is a liquid crystal display device having an enlarged viewing angle in all directions of up, down, left, and right.

A liquid crystal display device having a pair of substrates having at least one electrode disposed to face each other, a liquid crystal layer formed between the substrates, and a first polarizing plate disposed outside the liquid crystal layer, wherein the thickness d of the liquid crystal layer (μm ) And the product of refractive index anisotropy (Δn) (Δn · d) is 0.2 to 1.2 μm, and the alignment state of the liquid crystal layer is changed by applying an electric field of at least two or more values, and the liquid crystal when the electric field is applied or when no electric field is applied. The average orientation inclination angle of the layer with respect to the substrate surface is different, and the first polarizing plate is a polarizing film, a pair of protective films arranged by sandwiching the polarizing film, and a side outside the protective film and closer to the liquid crystal layer. It is a liquid crystal display device which has the optically anisotropic layer in which the disk compound located is hybrid-oriented, and at least one of the said pair of protective films satisfy | fills 25 + Re (633) <= Rth <= 250-Re (633).

LCD, Optical Compensation Film, Polarizer

Description

Optical Compensation Film, Polarizer and Liquid Crystal Display {OPTICAL COMPENSATION FILM, POLARIZING PLATE AND LIQUID CRYSTAL DISPLAY}

1 is a schematic view showing an example of a liquid crystal display device according to a first aspect of the present invention.

Fig. 2 is a graph showing the relationship between Re, Rth, and the down contrast ratio of a TN mode liquid crystal cell of a support film serving as a compensation film according to the first aspect of the present invention.

3 is a schematic diagram illustrating a configuration example of a liquid crystal display device according to a second aspect of the present invention.

4 is a graph showing optical characteristics of an example of a transparent film used in the second aspect of the present invention.

5 is a schematic diagram of a Poincare sphere used for explaining a change in polarization state of incident light in an example of a conventional liquid crystal display device.

6 is a schematic view of a Poincare sphere used for explaining a change in polarization state of incident light in a liquid crystal display device according to a second aspect of the invention.

7 is a schematic diagram illustrating a configuration example of a liquid crystal display device of a conventional TN mode.

* Explanation of symbols for main parts of drawings *

1: Upper polarizer outer protective film

2: slow polarizer outer protective film slow axis

3: upper polarizing plate polarizing film

4: upper polarizer polarizing film absorption axis

5: Upper polarizing plate liquid crystal cell side protective film (support)

6: Upper polarizer liquid crystal cell side protective film (support) slow axis

7: upper optically anisotropic layer

8: Rubbing direction for orientation of the support body side of an upper side optically anisotropic layer

9: liquid crystal cell upper substrate

10: rubbing direction for liquid crystal orientation of the upper substrate

11: liquid crystal molecule (liquid crystal layer)

12: rubbing direction for lower substrate liquid crystal alignment

13: liquid crystal cell lower substrate

14: lower optically anisotropic layer

15: Rubbing facing for orientation of support side of lower optically anisotropic layer

16: Lower polarizing plate liquid crystal cell side protective film (support)

17: lower polarizer liquid crystal cell side protective film (support) slow axis

18: lower polarizing plate polarizing film

19: Absorption axis of lower polarizing plate polarizing film

20: lower polarizing plate outer protective film

21: slow polarizer outer protective film slow axis

22: backlight

51: polarizing film

52: transmission axis

53: transparent film

53a: in-plane slow axis

55: optically anisotropic layer

55a: Orientation average direction of polarizing film side (transparent film interface side) of molecular symmetry axis of liquid crystalline compound

56: substrate

57: liquid crystal component

58: substrate

59: optically anisotropic layer

59a: orientation average direction of the polarization film side (transparent film interface side) of the molecular symmetry axis of the liquid crystal compound

61: polarizing film

62: transmission axis

63: transparent film

63a: In-plane slow axis

73: transparent support of optically anisotropic layer

83: transparent support of optically anisotropic layer

The present invention relates to a polarizing plate and a liquid crystal display device having an optically anisotropic layer containing a discotic compound. The present invention also relates to an optical compensation film having an optically anisotropic layer containing a discotic compound and a liquid crystal display device using the same.

The liquid crystal display device usually consists of a liquid crystal cell, a polarizing element and an optical compensation film (retardation plate). In a transmissive liquid crystal display device, normally two polarizing elements are arrange | positioned at both sides of a liquid crystal cell, and one or two optical compensation films are arrange | positioned between a liquid crystal cell and a polarizing element. In a reflective liquid crystal display device, a reflecting plate, a liquid crystal cell, an optical compensation film, and a polarizing element are usually arranged in this order. The liquid crystal cell consists of a rod-like liquid crystalline molecule, two substrates for encapsulating it, and an electrode layer for applying a voltage to the rod-like liquid crystalline molecule. The liquid crystal cell is a difference in the orientation state of the rod-like liquid crystalline molecules, and for the transmissive type, TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal), OCB (Optically Compensatory Bend), and STN (Super Twisted Nematic) ), Various display modes such as VA (Vertically Aligned), ECB (Electrically Controlled Birefringence), and reflection type are proposed, such as TN, Hybrid Aligned Nematic (HAN), and GH (Guest-Host).

Optical compensation films are used in various liquid crystal display devices in order to eliminate image coloring and to enlarge a viewing angle. As the optical compensation film, a stretched birefringent polymer film is conventionally used. In addition, it is proposed to use an optical compensation film having an optical anisotropic layer formed of a low molecular or high molecular liquid crystalline compound on a transparent support instead of the optical compensation film made of a stretched birefringent film. Since a liquid crystal compound has various orientation forms, the optical property which cannot be acquired with the conventional stretch birefringent polymer film can be implement | achieved by using a liquid crystal compound. Moreover, the structure which serves as a protective film and an optical compensation film is also proposed by adding birefringence to the protective film of a polarizing plate.

For applications requiring high display quality among LCDs, a 90-degree twisted nematic liquid crystal display device (hereinafter referred to as TN mode) driven by a thin film transistor using nematic liquid crystal molecules having positive dielectric anisotropy is mainly used. As an optical compensation film which enlarges the viewing angle of a TN mode liquid crystal layer liquid crystal display cell, the optical compensation film produced by fixing the disk-shaped compound in the state which hybridized was oriented is used (for example, Japanese Patent No. 2587398). In this method, since the nematic liquid crystal cell which consists of rod-shaped liquid crystals is compensated by the disk shaped compound, compensation is possible also about incident light from an oblique direction, and it is possible to enlarge a display viewing angle especially. In this case, with respect to the TN liquid crystal cell in which the rod-shaped molecules are twisted nematically, two compensation films made of a disc-shaped compound are arranged on the back side on which the display surface side and the backlight are arranged. The azimuth direction in which the disc-shaped compound is oriented is designed to enlarge the viewing angle by reducing the black transmittance in the up, down, left, and right directions by effectively compensating for the voltage applied black display in the normally used white mode TN liquid crystal display device. have.

Expansion of the viewing angle was achieved by optically compensating the alignment state of the liquid crystal layer of the liquid crystal display device with a disk compound. However, in this compensation method, the viewing angle region (contrast viewing angle) capable of maintaining high contrast in the TN liquid crystal display is enlarged, but the viewing angle compensation of the polarizer is not completely solved.

In a liquid crystal display device, a pair of polarizing plates are arrange | positioned above and below a liquid crystal layer, and let the absorption axis be orthogonal. Thereby, the transmittance | permeability of the front of a display apparatus turns black, and an image with high contrast is obtained. However, when the display device is observed in the inclined direction in this state, the angle of intersection of the upper and lower polarizing plate absorption axes becomes an angle larger than 90 ° in appearance, and leakage light is generated and the contrast ratio is lowered. That is, the TN mode has excellent display characteristics when viewed from the front, but has a viewing angle characteristic that the display characteristics are deteriorated due to a decrease in contrast or gray level inversion in which brightness is reversed in gray scale display when viewed in an inclined direction. This improvement is strongly desired. In particular, the market demand for contrast is strong, and there is a strong demand for further improvement in visual contrast, particularly in the up, down, left, and right directions.

In order to achieve a wider viewing angle, it is necessary to compensate for the viewing angle of the polarizing plate. For example, Japanese Patent No. 35,6830 discloses a polarizing plate in which the viewing angle is compensated.

However, in the method shown in Japanese Patent No. 3352730, two optical compensation films are required again, so that the light leakage due to the increase in thickness of the display device or the crossing angle error during bonding, and the warpage of the display device due to the change over time, A problem arises.

A method of improving the visual characteristics by controlling the wavelength dispersion of the optical compensation film is also proposed (for example, Japanese Patent Laid-Open No. 2003-202572). However, it is difficult to obtain good visual characteristics only by controlling the optical parameters of wavelength dispersion known in the art as in this method.

A first object of the present invention is to industrially realize that the contrast viewing angle of the liquid crystal display device of the TN liquid crystal mode is further enlarged, thereby improving the reliability of the display performance of such a liquid crystal display device. That is, the present invention provides a liquid crystal display device having an improved contrast viewing angle, particularly a TN mode liquid crystal display device, and a polarizing plate that contributes to the improvement of the contrast viewing angle of the liquid crystal display device.

It is also a second object of the present invention to provide a liquid crystal display device having a high optical contrast, in particular a liquid crystal display device of TN mode, in which the liquid crystal cell is exactly optically compensated. In addition, to provide an optical compensation film that optically compensates for a liquid crystal cell, particularly a TN mode liquid crystal, contributes to the improvement of visual contrast and to the reduction of black luminance floating in the visible light wavelength region in black display.

The said 1st subject is solved by following [1]-[6], and the said 2nd subject is solved by following [7]-[11].

[1] A liquid crystal display device comprising a pair of substrates having electrodes at least on one side and opposing each other, a liquid crystal layer formed between the substrates, and a first polarizing plate disposed outside the liquid crystal layer,

The product (Δn · d) of the thickness d (μm) of the liquid crystal layer and the refractive index anisotropy (Δn) is 0.2 to 1.2 μm, and the alignment state of the liquid crystal layer is changed by applying an electric field of at least two or more values, and an electric field is applied. The average alignment inclination angle of the liquid crystal layer with respect to the substrate surface is different at the time of no application of electric field and

The first polarizing plate contains a polarizing film, a pair of protective films sandwiched by the polarizing film, and a disk-shaped compound fixed in a hybrid alignment state positioned outside of the protective film and closer to the liquid crystal layer. Has an optically anisotropic layer,

A liquid crystal display device in which at least one of the pair of protective films satisfies the following formula (I).

(I) 25 + Re (633) ≤Rth≤250-Re (633)

[Wherein Re (λ) is the front retardation value (unit: nm) at wavelength λ nm, and Rth (λ) is the retardation value (unit: nm) in the film thickness direction at wavelength λ nm. D is the thickness of the film]

[2] The liquid crystal display device according to [1], wherein at least one of the protective films satisfies the following formula (II).

(II) 5≤ | Re (633) |

[3] The liquid crystal display device according to [1] or [2], wherein Δnd of the liquid crystal layer and at least one of Re and Rth of the protective film satisfy the following formulas (III) and (IV) at a wavelength of 400 to 700 nm.

(III) Rth≤Δnd / 2

(IV) Re≤Δnd / 2

[4] The liquid crystal display device according to any one of [1] to [3], wherein the slow axis of the protective film close to the liquid crystal layer and the polarization film absorption axis intersect.

[5] a pair of the optically anisotropic layer comprising a polarizing film, a pair of protective films sandwiched by the polarizing film, and an optically anisotropic layer disposed on an outer side of the protective film and fixed in a hybrid alignment state. At least one of the protective films satisfies the following formula (I).

(I) 25 + Re (633) ≤Rth≤250-Re (633)

[Wherein, Re (λ) is the front retardation value (unit: nm) at the wavelength λ nm, and Rth (λ) is the retardation value (unit: nm) in the film thickness direction at the wavelength λ nm. D is the thickness of the film]

[6] The polarizing plate of [5], wherein the polarizing film and the pair of protective films are bonded to each other with a roll to roll.

[7] An optical compensation film having at least an optically anisotropic layer having an optical anisotropy in the transparent film and the plane,

When the in-plane retardation of the transparent film is Re and the retardation in the thickness direction is Rth, the ratio Re / Rth (450 nm) of Re and Rth at a wavelength of 450 nm is equal to Re / Rth at a wavelength of 550 nm. 550 nm), 0.39 to 0.95 times, Re / Rth (650 nm) at wavelength 650 nm, 1.04 to 2.20 times Re / Rth (550 nm), and Rth at wavelength 550 nm is 70 nm to 400 nm. ,

The optically anisotropic layer is formed of a composition containing a liquid crystalline compound, wherein molecules of the liquid crystalline compound in the optically anisotropic layer are fixed in an alignment state, and at least at the transparent film side interface of the molecular symmetry axis of the liquid crystalline compound. An optical compensation film having an intersection angle between a direction in which an orientation average direction is orthogonal in the plane of the transparent film and a slow axis in the plane of the transparent film is about 0 degrees or about 90 degrees.

[8] The optical compensation film of [7], wherein the liquid crystalline compound is a discotic liquid crystalline compound.

[9] A pair of substrates disposed opposite each other having an electrode on at least one of them, and a pair of substrates sandwiched by the pair of substrates, wherein the liquid crystal molecules of the nematic liquid crystal material are non-driven. A liquid crystal cell having a liquid crystal layer oriented approximately parallel to the surface of the substrate and having a product (Δn · d) of thickness d (micron) and refractive index anisotropy (Δn) of 0.1 to 1.5 microns,

First and second polarizing films arranged to sandwich the liquid crystal cell, and

Having a transparent film between at least one of the first and second polarizing films and the liquid crystal cell,

When the in-plane retardation of the transparent film is Re and the retardation in the thickness direction is Rth, the ratio Re / Rth (450 nm) of Re and Rth at a wavelength of 450 nm is equal to Re / Rth at a wavelength of 550 nm. 550 nm), 0.39 to 0.95 times, Re / Rth (650 nm) at wavelength 650 nm, 1.04 to 2.20 times Re / Rth (550 nm), and Rth at wavelength 550 nm of the transparent film is 70 Nm to 400 nm,

At least one optically anisotropic layer is provided between the said transparent film and the said liquid crystal cell, The said optically anisotropic layer is formed from the composition containing a liquid crystalline compound, and the molecule | numerator of the said liquid crystalline compound is the orientation state among the optically anisotropic layers. The angle of intersection of the orientation average direction at least at the interface of the transparent film side of the molecular symmetry axis of the liquid crystalline compound in the plane of the transparent film and the slow axis in the plane of the transparent film is about 0 degrees. Or about 90 degrees.

[10] The liquid crystal display device according to [9], wherein the liquid crystalline compound is a discotic liquid crystalline compound.

[11] The liquid crystal display device according to [9] or [10], wherein the liquid crystal cell is a TN mode liquid crystal cell.

In addition, in this specification, Re ((lambda)) and Rth ((lambda)) represent in-plane retardation in the wavelength (lambda), and retardation of the thickness direction, respectively. Re (λ) is measured by injecting light having a wavelength of λ nm in the film normal direction in KOBRA 21ADH (manufactured by Oji measurement equipment Co., Ltd.). Rth (λ) is a light having a wavelength of λnm from a direction inclined at + 40 ° with respect to the film normal direction using Re (λ) and the in-plane slow axis (determined by KOBRA 21ADH) as the inclination axis (rotation axis). Measured in three directions of the retardation value measured by injecting light having a wavelength of λ nm in the direction inclined at -40 ° to the film normal direction using the measured retardation value and the in-plane slow axis as the inclination axis (rotation axis). Based on the retardation value, the assumption of the average refractive index and the input film thickness value, KOBRA 21ADH is calculated. Here, the assumption of the average refractive index may be a polymer handbook (JOHN WILEY & SONS, INC), catalog values of various optical films. If the value of the mean refractive index is not already known, it can be measured with an Abbe refractometer. The value of the average refractive index of a main optical film is illustrated below:

Cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethylmethacrylate (1.49), polystyrene (1.59).

KOBRA 21ADH calculates nx, ny, and nz by inputting the assumption values and the film thickness of these average refractive indices. From this calculated nx, ny and nz, Nz = (nx-nz) / (nx-ny) is calculated again.

In addition, in this specification, a "ground axis" means the direction in which a refractive index becomes largest. In addition, in this specification, "polarizing plate" is used by the meaning containing both a long polarizing plate and the polarizing plate cut | jipped to the magnitude | size attached to a liquid crystal device, unless it mentions specially. In addition, although a "polarizing film" and a "polarizing plate" are distinguished and used in this specification, a "polarizing plate" shall mean the laminated body which has a transparent protective film which protects this polarizing film on at least one surface of a "polarizing film."

In addition, in this specification, "45 degree", "parallel", or "orthogonal" means that it exists in the range of less than an exact angle +/- 5 degree. It is preferable that it is less than 4 degrees, and, as for the error with an exact angle, it is more preferable that it is less than 3 degrees. In addition, "+" means clockwise with respect to an angle, and "-" shall mean counterclockwise.

In addition, a "visible light region" means that it is 380 nm-780 nm. In addition, the measurement wavelength of refractive index is a value in (lambda) = 550 nm of visible range unless there is particular notice.

In addition, in this specification, when a molecule | numerator has a rotation symmetry axis | shaft, it means the symmetry axis | shaft, but it does not require that a molecule is rotationally symmetrical in a strict meaning. In general, the molecular symmetry axis coincides with the axis perpendicular to the disc surface penetrating the center of the disc surface in the discotic liquid crystalline compound, and coincides with the long axis of the molecule in the rod-like liquid crystalline compound.

Embodiment of the Invention

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

(1) First aspect of the present invention

[LCD]

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram concerning the structural example of embodiment which applied the 1st aspect of this invention to the transmissive liquid crystal display device.

The transmissive liquid crystal display device shown in FIG. 1 serves as the transparent protective film 1, the polarizing film 3, the transparent protective film (the transparent support of the optically anisotropic layer 7 in order from the observation side; 5) and the optically anisotropic layer ( 7) an observer side polarizing plate, a liquid crystal cell comprising an upper substrate 9 of a liquid crystal cell, a rod-shaped liquid crystal layer 11 and a lower substrate 13 of a liquid crystal cell, an optically anisotropic layer 14, and a transparent protective film (optical It serves as the transparent support of the anisotropic layer 14; 16, the lower polarizing plate which consists of the polarizing film 18, and the transparent protective film 20, and the backlight 22 is provided. And a transparent protective film, a polarizing film, a transparent support body, and optically anisotropic layers 1-7 and 14-21 comprise the polarizing plate which concerns on the 1st aspect of this invention.

It is preferable that liquid crystal cells 9-13 are liquid crystal cells of TN mode. In addition, the TN mode liquid crystal cell is most commonly used as a color TFT liquid crystal display device, and many documents have been described. In this embodiment, the example which used the liquid crystal cell of TN mode which consists of nematic liquid crystal which has positive dielectric anisotropy is demonstrated.

Dielectric anisotropy is positive between the upper and lower substrates 9 and 13, and the liquid crystal of refractive index anisotropy (DELTA) n = 0.0854 (589 nm, 20 degreeC) and dielectric constant anisotropy (DELTA) epsilon = +8.5 is enclosed. The product (Δn · d) of the thickness d (μm) of the liquid crystal layer 11 and the refractive index anisotropy (Δn) is set to 0.2 to 1.2 μm. It is preferable to set it as 0.2-0.5 micrometer. The alignment control of the liquid crystal layer 11 can be controlled by the surface properties of the alignment film (not shown) formed on the inner surfaces of the upper and lower substrates 9 and 13 and the rubbing axes 10 and 12. It is preferable that the director and the so-called tilt angle which show the orientation direction of a liquid crystal molecule shall be about 3 degrees. The rubbing direction is carried out in directions perpendicular to each other on the upper and lower substrates 9 and 13, and the magnitude of the tilt angle can be controlled by the strength, the number of rubbings, and the like. It is preferable to form an alignment film by baking, after apply | coating a polyimide film. The twist angle size of the liquid crystal layer 11 is determined by the crossing angle of the rubbing direction of the upper and lower substrates 9 and 13 and the chiral agent added to the liquid crystal material. For example, in order to make a twist angle 90 degrees, it is preferable to add the chiral agent about 60 micrometers in pitch. The thickness d of the liquid crystal layer 11 may be, for example, about 5 μm. The liquid crystal material (LC) to be used is not particularly limited as long as it is a nematic liquid crystal. The larger the value of the dielectric anisotropy Δε, the lower the driving voltage can be. The smaller the refractive index anisotropy Δn can increase the thickness (gap) of the liquid crystal layer and reduce the gap deviation. In addition, the larger Δn can make the cell gap smaller, thereby enabling high-speed response. In addition, the twist angle (torsion angle) of the liquid crystal layer is generally twisted clockwise from the observation side toward the display observation side from the light source side, so that the vicinity of 90 ° (85 ° to 95 °) becomes an optimum value. In these ranges, a bright and high contrast display device is obtained in that white display brightness is high and black display brightness is small.

The upper polarizing plate and the lower polarizing plate each have a pair of transparent protective films 1 and 5 and 16 and 20, and an optically anisotropic layer 7 and 14 containing a disk compound fixed in a hybrid alignment state. The pair of protective films 1 and 5 and 16 and 20 have at least one optical property satisfying the following formula (I) (preferably the following formula (I '), more preferably the following formula (I "). It is preferable that at least the protective film on the light source side satisfies the following formula (I) among the pair of protective films, and both of the pair of protective films are the following formula (I) (more preferably the following formula (I '), and further It is preferable to satisfy following formula (I ") preferably.

(I) 25 + Re (633) ≤Rth≤250-Re (633)

(I ') 25 + Re (633) ≤ Rth ≤ 175 + Re (633)

Rth≤250-Re (633)

(I ") 50 + Re (633) ≤ Rth ≤ 150 + Re (633)

Rth≤150-Re (633)

[In formula, Re ((lambda)) is a front-side retardation value (unit: nm) in wavelength (lambda) nm, Rth ((lambda)) is a retardation value (unit: nm) of the film thickness direction in wavelength (lambda) nm. D is the thickness of the film].

When the protective film satisfies the optical characteristics, the contrast viewing angle of the liquid crystal display is enlarged in the embodiments described below. However, in theory, when the above satisfies the above equation, a pair of polarizing plates having an orthogonal absorption axis is observed in the oblique direction. The polarizing plate crossing angle of the external appearance at the time of correction | amendment is correct | amended, and it is considered to be orthogonal even if it observes from what angle.

The pair of protective films 1 and 5 and 16 and 20 has at least one (more preferably at least a protective film on the liquid crystal layer side, and more preferably both protective films) having an absolute value of Re at 5 nm at a wavelength of 633 nm. It is preferable that it is above, and it is more preferable that it is 10 nm or more. In addition, the pair of protective films 1 and 5 and 16 and 20 has at least one (more preferably at least a protective film on the liquid crystal layer side, more preferably both protective films) at a wavelength of 400 to 700 nm for both Re and Rth. It is preferable that it is half or less of the retardation ((DELTA) nd) of.

The absorption axis 4 of the upper polarizing film 3 and the absorption axis 19 of the lower polarizing film 18 are approximately orthogonally stacked, and the absorption axis 4 of the upper polarizing film 3 of the liquid crystal cell and the upper side thereof. The rubbing direction 10 of the board | substrate 9 is laminated | stacked, and the absorption axis 19 of the lower polarizing film 18 and the rubbing direction 12 of the lower board | substrate 13 are laminated so that it may become substantially parallel, respectively. The rubbing direction 8 of the optically anisotropic layer 7 is preferably arranged in parallel with the absorption axis 4 of the upper polarizing film 3 and antiparallel to the rubbing direction 10 of the upper substrate 9. The rubbing direction 15 of the optically anisotropic layer 14 is preferably arranged parallel to the absorption axis 19 of the lower polarizing film 18 and antiparallel to the rubbing direction 10 of the lower substrate 12. In addition, when the protective films 5 and 16 arrange | positioned at the position near a liquid crystal cell have in-plane slow axes 6 and 17, the slow axes 6 and 17 are arrange | positioned crossing the absorption axes 4 and 19, respectively. It is preferable to arrange | position it at about 90 degrees.

A transparent electrode (not shown) is formed inside the alignment film of each of the upper substrate 9 and the lower substrate 13, and in a non-driven state in which no driving voltage is applied to the electrode, the liquid crystal molecules in the liquid crystal cell are approximately with respect to the substrate surface. As a result, the polarization state of the light passing through the liquid crystal panel is propagated along the twisted structure of the liquid crystal molecules, and the polarization plane is rotated by 90 ° to exit. That is, the liquid crystal display realizes white display in a non-driven state. In contrast, in the driving state, the liquid crystal molecules are aligned in a direction forming an angle with respect to the substrate surface, and the light passing through the lower polarizing film 18 passes through the liquid crystal layer 11 while maintaining the polarization state and polarizes. Blocked by the membrane 3. In other words, a black display is obtained in the driving state. Since the liquid crystal display device includes optical compensation layers 7 and 14 and a pair of protective films 1 and 15 and 16 and 20 that satisfy predetermined optical characteristics, gray scale inversion occurs depending on the viewing direction. The phenomenon is reduced and the viewing angle is improved.

The above embodiment is a transmissive mode, and the Δnd value of the liquid crystal cell also shows a suitable value in the transmissive mode. However, the liquid crystal display device according to the first aspect of the present invention may be a reflective mode. In terms of double, the optimum? Nd value is about 1/2 of the above. In addition, the twist angle of 30 ° to 70 ° is an optimal value.

The liquid crystal display device which concerns on the 1st aspect of this invention is not limited to the structure shown in FIG. 1, and may contain the other member. For example, you may arrange a color filter between a liquid crystal cell and a polarizing film. A cold cathode or hot cathode fluorescent tube, or a backlight having a light emitting diode, a field emission device, and an electroluminescent device as a light source can be disposed. The liquid crystal display device according to the first aspect of the present invention may be a transflective type in which a reflection part and a transmission part are formed in one pixel of the display device in order to achieve both transmission and reflection modes.

The liquid crystal display device according to the first aspect of the present invention includes an image direct view type, an image projection type, and a light modulation type. The present invention is particularly effective in the embodiment applied to an active matrix liquid crystal display device using a three-terminal or two-terminal semiconductor element such as a TFT or a MIM. Of course, the aspect applied to the passive matrix liquid crystal display device is also effective.

[Polarizing Plate]

Next, the polarizing plate which concerns on the 1st aspect of this invention is demonstrated. The polarizing plate which concerns on the 1st aspect of this invention is an optical anisotropy containing a polarizing film, a pair of protective film which clamps the polarizing film, and the disk-shaped liquid crystal compound fixed in the hybrid orientation state on one outer side of the pair of protective films. Has a layer. Hereinafter, the various members used for the polarizing plate which concerns on the 1st aspect of this invention are demonstrated.

[Shield]

At least one of the pair of protective films protecting the polarizing film satisfies the above formula (I). The material is not particularly limited as long as it has the properties required for the protective film. Moreover, since a protective film on the optically anisotropic layer side is used as a support body which supports an optically anisotropic layer among a pair of protective films, since it can be made thin, it is preferable. It is preferable that a protective film is transparent, and it is preferable that specifically, light transmittance is 80% or more. It is preferable to select a protective film from a polymer film. Examples of the polymer constituting the polymer film include cellulose esters (eg, mono-triacylate bodies of cellulose), norbornene-based polymers, and polymethyl methacrylates. A commercially available polymer (in the norbornene-based polymer, both Aton and Zeonex trade names) may be used. Moreover, even if it is a polymer which birefringence is easy to express like conventionally known polycarbonate and polysulfone, as described in WO00 / 26705 specification, it can also be used for the 1st aspect of this invention, if the expression of birefringence is controlled by modifying a molecule | numerator. have.

Especially, a cellulose ester is preferable and the lower fatty acid ester of cellulose is more preferable. Lower fatty acids mean fatty acids having 6 or less carbon atoms. In particular, cellulose acylate having 2 to 4 carbon atoms is preferable. Cellulose acetate is particularly preferred. You may use mixed fatty acid ester, such as a cellulose acetate propionate and a cellulose acetate butyrate.

It is preferable that it is 250 or more, and, as for the viscosity average polymerization degree (DP) of cellulose acetate, it is more preferable that it is 290 or more. In addition, the cellulose acetate preferably has a narrow molecular weight distribution of Mw / Mn (Mw is mass average molecular weight and Mn is number average molecular weight) by gel permeation chromatography. As a specific value of Mw / Mn, it is preferable that it is 1.0-1.7, and it is more preferable that it is 1.0-1.65.

Moreover, it is preferable to use the cellulose acetate whose acetylation degree is 55.0-62.5%. The degree of acetylation is more preferably 57.0 to 62.0%. Acetylation degree means the amount of bound acetic acid per cellulose unit mass. Acetylation degree is calculated | required by measurement and calculation of the acetylation degree in ASTM: D-817-91 (test methods, such as a cellulose acetate).

Usually, the cellulose acetate does not substitute the hydroxyl of 2nd, 3rd, and 6th position of cellulose uniformly, and there exists a tendency for substitution degree of 6th position to become small. As for the cellulose acetate used for the said transparent support body, it is preferable that the 6th substitution degree of cellulose is about the same or more than 2nd and 3rd positions. It is preferable that the ratio of 6th substitution degree with respect to the sum total of 2nd, 3rd, 6th substitution degree is 30-40%, It is more preferable that it is 31-40%, It is most preferable that it is 32-40%. It is preferable that substitution degree of a 6th position is 0.88 or more.

Methods for synthesizing these specific acyl groups and cellulose acylate are described in detail on page 9 of the Korean Society of Publications (Publication No. 2001-1745, published on March 15, 2001).

In order to adjust the retardation of a polymer film and to give the optical characteristic which satisfy | fills said Formula (I), the method of giving external force like extending | stretching is common. If necessary, a retardation increasing agent for adjusting optical anisotropy, or a compound or a wavelength dispersion adjusting agent may be added to the polymer film in order to reduce the optical anisotropy. In order to adjust the retardation of a cellulose acylate film, it is preferable to use the aromatic compound which has at least two aromatic rings as a retardation increasing agent. It is preferable to use an aromatic compound in 0.01-20 mass parts with respect to 100 mass parts of cellulose acylates. Moreover, you may use together 2 or more types of aromatic compounds. The aromatic ring of the aromatic compound includes an aromatic hetero ring in addition to the aromatic hydrocarbon ring. For example, the compound etc. which were described in European Patent 0911656 A2 specification, Unexamined-Japanese-Patent No. 2000-111914, 2000-275434, etc. are mentioned.

Although the exemplary compound which can be used as a compound for reducing the optical anisotropy of a polymer film below, and the exemplary compound which can be used as a wavelength dispersion regulator are shown, it is not limited to the following compounds.

Examples of Compounds for Degrading Optical Anisotropy

Example of wavelength dispersion regulator

And it is preferable that the moisture absorption expansion coefficient of the cellulose acetate film used as a said protective film is 30x10 <^-5> /% RH or less. The hygroscopic expansion coefficient is preferably 15 × 10 ^-5 /% RH or less, and more preferably 10 × 10 ^-5 /% RH or less. Moreover, although the moisture absorption expansion coefficient is preferable, it is a value normally 1.0x10 <^-5> /% RH or more. The hygroscopic expansion coefficient represents the amount of change in the sample length when the relative humidity is changed under a certain temperature.

By adjusting the hygroscopic expansion coefficient, it is possible to prevent the increase in the frame-like transmittance (light leakage due to deformation) while maintaining the optical performance of the optically anisotropic layer and the polarizing film. It shows below about the measuring method of a moisture absorption expansion coefficient. Width from a polymer film produced 5㎜, the length was cut out of the sample 20㎜, by fixing the one end hung in an atmosphere of 25 ℃, 20% RH (R 0). A 0.5 g weight was hung on the other end and left for 10 minutes to measure the length (L ⁰ ). Next, the temperature (L ¹ ) was measured at a temperature of 25 ° C. with a humidity of 80% RH (R ¹ ). The hygroscopic expansion coefficient can be calculated by the following equation. 10 samples are taken for the same sample, and the average value is used.

Hygroscopic expansion coefficient [/% RH] = {(L ¹ -L ⁰ ) / L ⁰ } / (R ¹ -R ⁰ )

In order to reduce the dimensional change due to moisture absorption of the polymer film, it is preferable to add a compound having a hydrophobic group or fine particles. As a compound which has a hydrophobic group, it is preferable to select from the plasticizers and antideterioration agents which have a hydrophobic group, such as an aliphatic group and an aromatic group, in a molecule | numerator. It is preferable that the addition amount of these compounds exists in the range of 0.01-10 mass% with respect to the solution (dope) to adjust. Moreover, what is necessary is just to reduce the free volume in a polymer film, and the thing which has a small amount of the residual solvent at the time of film formation by the solventcast method mentioned later becomes small free deposition. It is preferable to dry on the conditions which become the range of 0.01-1.00 mass% of residual solvent amount with respect to a cellulose acetate film.

Additives added to the polymer film or additives added for various purposes (e.g. sunscreens, strippers, antistatic agents, anti-degradants (e.g. antioxidants, peroxide decomposers, radical inhibitors, metal deactivators, dispersions) Aggregates, amines), infrared absorbers, etc.) may be either solid or oily. Moreover, when a film is formed in multiple layers, the kind and addition amount of each layer additive may differ. For details, the materials described in detail on pages 16 to 22 of the above technique No. 2001-1745 are preferably used. Although the addition amount of each raw material is not specifically limited as long as the function is expressed, It is preferable that it is 0.001-25 mass% in the whole polymer film composition.

[Production Method of Polymer Film]

It is preferable to manufacture a polymer film by the solvent cast method. In the solvent cast method, a film is produced using a solution (dope) in which a polymer material is dissolved in an organic solvent. In the solvent cast method, the dope is cast on a drum or a band and the solvent is evaporated to form a film. It is preferable to adjust density | concentration so that dope before casting may be 18 to 35% of solid content. The surface of the drum or the band is preferably finished in the mirror state.

The dope is preferably cast on a drum or band having a surface temperature of 10 ° C or lower. It is preferable to dry by air for 2 seconds or more after being soft. The obtained film may be peeled off from the drum or the band, and dried again by hot air having gradually changed the temperature to 100 to 160 ° C to evaporate the residual solvent. The above method is described in JP-A-5-17844. According to this method, the time from casting to peeling can be shortened. In order to carry out this method, the dope needs to be gelated at the surface temperature of the drum or band during casting.

In a casting | flow_spread process, one type of cellulose acylate solution may be single-layer cast, and two or more types of cellulose acylate solutions may be simultaneously and / or gradually covalently smoked.

As a method of co-linking a plurality of cellulose acylate solutions of two or more layers as described above, for example, a solution containing cellulose acylate may be cast from a plurality of oil studies formed at intervals in the advancing direction of the support. A method of laminating (for example, the method described in JP-A-11-198285), a method of casting a cellulose acylate solution from two oil studies (the method described in JP-A-6-134933), high viscosity The method of wrapping a flow of a cellulose acylate solution with a low viscosity cellulose acylate solution, and simultaneously extruding a low viscosity cellulose acylate solution (method of Unexamined-Japanese-Patent No. 56-162617), etc. are mentioned. In the 1st aspect of this invention, it is not limited to these.

The manufacturing process of these solvent cast methods is described in detail on pages 22 to 30 of the above air number 2001-1745, and classified into dissolution, casting (including covalent lead), metal support, drying, peeling, stretching and the like. .

It is preferable that it is 15-120 micrometers, and, as for the thickness of the film used as the said protective film, it is more preferable that it is 30-80 micrometers.

[Surface Treatment of Polymer Film]

The polymer film is preferably surface treated. Surface treatments include corona discharge treatment, glow discharge treatment, flame treatment, acid treatment, alkali treatment and ultraviolet irradiation treatment. These are described in detail in pages 30 to 32 of the aforementioned air number 2001-1745. Among these, especially preferably, it is an alkali saponification process and is very effective as a surface treatment of a cellulose acylate film.

Alkali saponification treatment may be any of immersion in the saponification liquid and coating of the saponification liquid, but a coating method is preferable. Examples of the coating method include a dip coating method, curtain coating method, extrusion coating method, bar coating method and E type coating method. Examples of the alkaline soap treatment solution include potassium hydroxide solution and sodium hydroxide solution, and the prescribed concentration of hydroxide ions is preferably in the range of 0.1 to 3.0N. The saponification solution is prepared by containing a solvent having good wettability with respect to the film (e.g. isopropyl alcohol, n-butanol, methanol, ethanol, etc.), a surfactant, and a humectant (e.g. diols, glycerin, etc.) as the alkali treatment liquid. The wettability with respect to the transparent support, saponification liquid, etc. become good at time stability. Specifically, the content of Unexamined-Japanese-Patent No. 2002-82226 and WO02 / 46809 is mentioned, for example.

Instead of the surface treatment, in addition to the surface treatment, it is a single layer method of applying a single layer of a resin layer such as a undercoat layer (described in JP-A-7-333433) or a gelatin containing both a hydrophobic group and a hydrophilic group. A so-called middle layer which forms an adhesive layer (hereinafter, abbreviated as first layer below) and applies a hydrophilic resin layer (hereinafter, abbreviated as second layer) such as gelatin to adhere well to the alignment film as a second layer thereon. The content of the method (for example, Unexamined-Japanese-Patent No. 11-248940) is mentioned.

[Optical anisotropic layer]

The optically anisotropic layer contains a discotic compound fixed in a hybrid alignment state. Hereinafter, the preferable aspect of an optically anisotropic layer is described in detail.

The optically anisotropic layer is preferably designed to compensate for the liquid crystal compound in the liquid crystal cell in the black display of the liquid crystal display device. The alignment state of the liquid crystal compound in the liquid crystal cell in the black display varies depending on the mode of the liquid crystal display device. The orientation state of the liquid crystal compound in this liquid crystal cell and the orientation relationship of the compensation film are described in IDW'00, FMC7-2, and P411-414.

In the optically anisotropic layer, since the discotic compound is hybridly oriented, the average of the inclination angle with respect to the layer plane of the major axis (long diameter of the disc) of the discotic compound is the depth direction of the optically anisotropic layer and the distance from the transparent supporter interface. It is increasing or decreasing with increase. It is preferable that the average of the inclination angles increases with increasing distance. In addition, the change of the inclination angle may be a continuous increase, a continuous decrease, an intermittent increase, an intermittent decrease, a change including a continuous increase and a continuous decrease, or an intermittent change including an increase and a decrease. The intermittent change includes a region in which the inclination angle does not change in the thickness direction. In the first aspect of the present invention, even if the inclination angle includes a region that does not change, it may be increased or decreased as a whole. And it is preferable that the inclination angle changes continuously.

The optically anisotropic layer may be formed by applying a composition containing a liquid crystalline disk compound to the surface of the transparent support and heating it if necessary. In order to make a liquid crystalline disk-like compound into the above-mentioned desired orientation state, it is preferable to use the material which controls the orientation of liquid crystalline molecules, such as an orientation film, a chiral agent, surfactant, and a polymer. For example, when an alignment film is used, the alignment direction of the major axis of the liquid crystalline disk compound at the alignment film interface can be adjusted in a desired direction by selecting a material of the alignment film or by selecting a rubbing treatment method. In addition, the long-axis (disc surface) direction of the disk-shaped compound on the surface side (air side) can generally be adjusted by selecting the type of the disk compound or the additive to be used with the disk-shaped compound. In addition, in the composition for optically anisotropic layer formation, you may contain the polymeric monomer, initiator, etc. which are used for fixing a liquid crystalline disk-like compound.

Discoid Compound

Examples of discotic (discotic) compounds that can be used in the first aspect of the present invention include C. Destrade et al., Mol. Cryst. Benzene derivatives described in Vol. 71, p. 111 (1981), C. Destrade et al., Mol. Cryst. A report of the Truxen derivative, B. Kohne et al., Described in Vol. 122, 141 (1985), Physics lett, A, 78, 82 (1990), Angew. Chem. The cyclohexane derivatives described in Volume 96, page 70 (1984) and J. M. Lehn et al., J. Chem. Commun., Page 1794 (1985), by J. Zhang et al., J. Am. Chem. Soc. Azacrown-based or phenylacetylene-based macrocycles described in volume 116, page 2655 (1994).

Examples of the disk-shaped compound also include compounds exhibiting liquid crystallinity which is a structure in which a linear alkyl group, an alkoxy group, and a substituted benzoyloxy group are radially substituted as the side chain of the mother nucleus with respect to the mother nucleus of the molecular center. It is preferable that a molecule | numerator or an aggregate of molecules is a compound which has rotational symmetry and can give a fixed orientation. Preferred examples of the discotic compound are described in Japanese Patent Laid-Open No. 8-50206.

[Additive of optically anisotropic layer]

The composition for optically anisotropic layer formation can contain various additives including a chiral agent besides the said disk shaped compound. Examples of the additive include plasticizers, surfactants, polymerizable monomers, and the like. These additives contribute to improving the uniformity of the coating film, the strength of the film or the orientation of the discotic compound, and the like. As surfactant, the following fluorine-containing surfactant is mentioned, for example.

Fluorine-containing surfactant

A radically polymerizable or cationically polymerizable compound is mentioned as a polymerizable monomer. Preferably it is a polyfunctional radically polymerizable monomer, and it is preferable that it is copolymerizable with said polymerizable group containing liquid crystal compound. For example, the thing of Paragraph No. [0018]-[0020] is mentioned in Unexamined-Japanese-Patent No. 2002-296423 specification. It is preferable that the addition amount of the said compound exists in the range of 1-50 mass% generally with respect to a disk shaped compound, and is in the range of 5-30 mass%.

Although a conventionally well-known compound is mentioned as surfactant, Especially a fluorine-type compound is preferable. Specifically, the compound described in Paragraph No. [0028]-[0056] of Unexamined-Japanese-Patent No. 2001-330725 can be mentioned, for example.

It is preferable that the polymer used with a discoid compound can change the inclination angle of a discoid compound.

Examples of the polymer include cellulose esters. As a preferable example of a cellulose ester, the thing of Paragraph No. [0178] of Unexamined-Japanese-Patent No. 2000-155216 specification is mentioned. It is preferable to exist in the range of 0.1-10 mass% with respect to a liquid crystalline disk compound, and, as for the addition amount of the said polymer so that the orientation of a liquid crystalline disk compound is not impaired, it is more preferable to exist in the range of 0.1-8 mass%.

[Formation of Optically Anisotropic Layer]

An optically anisotropic layer can be formed by apply | coating the coating liquid containing a liquid crystalline disk compound and an additive etc. to the surface of an oriented film as needed.

As a solvent used for preparation of a coating liquid, an organic solvent is used preferably. Examples of organic solvents include amides (eg N, N-dimethylformamide), sulfoxides (eg dimethyl sulfoxide), heterocyclic compounds (eg pyridine), hydrocarbons (eg benzene, hexane), alkyl halides ( Chloroform, dichloromethane, tetrachloroethane), esters (e.g. methyl acetate, butyl acetate), ketones (e.g. acetone, methylethylketone), ethers (e.g. tetrahydrofuran, 1,2-dimethoxyethane) This includes. Alkyl halides and ketones are preferred. You may use together 2 or more types of organic solvents.

Application of the coating liquid can be carried out by a known method (eg, wire bar coating method, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method).

[Fixing of Discoid Compounds]

The liquid crystalline disk-shaped compound can be fixed while maintaining the alignment state. It is preferable to perform fixation by a polymerization reaction. Polymerization includes thermal polymerization using a thermal initiator and photopolymerization using a photopolymerization initiator. Photopolymerization is preferred.

Examples of the photopolymerization initiator include α-carbonyl compounds (described in the specifications of US Pat. No. 23,676, 61,673,670), acyloinether (described in the specification of US Pat. No. 2448828), compounds of the α-hydrocarbon substituted aromatic acyl (US patent). 2722512 specification), polynuclear quinone compound (see US Patent 3046127, each specification of US 2951758), combination of triarylimidazole dimer and p-aminophenyl ketone (described in US Pat. No. 3549367), acridine And phenazine compounds (JP-A-60-105667, described in US Pat. No. 4239850) and oxadiazole compounds (described in US Pat. No. 4212970).

It is preferable that the usage-amount of a photoinitiator exists in the range of 0.01-20 mass% of solid content of a coating liquid, and it is more preferable to exist in the range which is 0.5-5 mass%.

It is preferable to use ultraviolet-ray for the light irradiation for superposition | polymerization of a liquid crystalline disk-shaped compound. The irradiation energy is preferably in the range of 20 mJ / cm 2 to 50 J / cm 2, more preferably in the range of 20 to 5000 mJ / cm 2, and even more preferably in the range of 100 to 800 mJ / cm 2. In addition, in order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions.

You may form a protective layer on an optically anisotropic layer.

[Alignment Film]

The alignment film has a function of defining the orientation direction of the discotic compound. It is preferable to use an alignment film in order to bring the liquid crystalline disc-shaped compound into the above-mentioned alignment state. However, if the alignment state is fixed after the liquid crystalline disc-shaped compound is oriented, the alignment film is not necessarily essential as a component. That is, it is also possible to transfer only the optically anisotropic layer on the alignment film to which the alignment state is fixed onto the transparent support.

The alignment film is an organic compound (e.g., ω-tricoic acid, di, by rubbing treatment of an organic compound (preferably a polymer), evaporation of an inorganic compound, formation of a layer having microgrooves, or by a Langmuir blowjet method (LB film)). Octadecyl methylammonium chloride, methyl stearyl acid). Also, an alignment film in which an alignment function is generated by application of an electric field, application of a magnetic field, or light irradiation is also known.

It is preferable to form an alignment film by the rubbing process of a polymer. The polymer used for an oriented film has a molecular structure which has a function which orientates a liquid crystalline molecule in principle. In the first aspect of the present invention, in addition to the function of orienting the liquid crystalline molecules, the side chain having a function of binding a side chain having a crosslinkable functional group (e.g., a double bond) to the main chain or aligning the liquid crystalline molecule is side chained. It is preferable to introduce in.

The polymer used for the alignment film may be either a polymer itself crosslinkable or a polymer crosslinked by a crosslinking agent, and a plurality of combinations thereof may be used.

Examples of the polymer include, for example, methacrylate copolymers, styrene copolymers, polyolefins, polyvinyl alcohols and modified polyvinyl alcohols, polys as described in paragraph [0022] of JP-A-8-338913. (N-methylol acrylamide), polyester, polyimide, vinyl acetate copolymer, carboxymethyl cellulose, polycarbonate, and the like. Silane coupling agents can be used as the polymer. Water-soluble polymers (e.g. poly (N-methylolacrylamide), carboxymethylcellulose, gelatin, polyvinyl alcohol, modified polyvinyl alcohol) are preferred, gelatin, polyvinyl alcohol and modified polyvinyl alcohol are more preferred, and poly Most preferred are vinyl alcohol and modified polyvinyl alcohol. It is especially preferable to use together two types of polyvinyl alcohol or modified polyvinyl alcohol from which a polymerization degree differs.

70-100% is preferable and, as for the saponification degree of polyvinyl alcohol, 80-100% is more preferable. It is preferable that the polymerization degree of polyvinyl alcohol is 100-5000.

Side chains having a function of orienting liquid crystalline molecules generally have a hydrophobic group as a functional group. The kind of specific functional group is determined according to the kind of liquid crystalline molecule and the orientation state required.

For example, the modified group of the modified polyvinyl alcohol may be introduced by copolymerization modification, chain transfer modification or block polymerization modification. Examples of the modified group include hydrophilic groups (carboxylic acid groups, sulfonic acid groups, phosphonic acid groups, amino groups, ammonium groups, amide groups, thiol groups, etc.), hydrocarbon groups having 10 to 100 carbon atoms, hydrocarbon groups having fluorine atom substitution, thioether groups, and polymerization. The group (unsaturated polymerizable group, epoxy group, aziridinyl group, etc.), an alkoxy silyl group (trialkoxy, dialkoxy, monoalkoxy), etc. are mentioned. Specific examples of these modified polyvinyl alcohol compounds include, for example, paragraphs [0022] to [0145] of JP 2000-155216, and paragraphs [0018] to [0022] of JP 2002-62426. The thing described in the above, etc. are mentioned.

When the side chain having the crosslinkable functional group is bonded to the main chain of the alignment film polymer or the crosslinking functional group is introduced into the side chain having the function of orienting the liquid crystal molecules, the polymer of the alignment film and the polyfunctional monomer included in the optically anisotropic layer may be copolymerized. Can be. As a result, not only between the polyfunctional monomer and the polyfunctional monomer, but also between the alignment film polymer and the alignment film polymer and between the polyfunctional monomer and the alignment film polymer are strongly bonded by covalent bonds. Therefore, the strength of the optical compensation film can be remarkably improved by introducing the crosslinkable functional group into the alignment film polymer.

It is preferable that the crosslinkable functional group of an oriented film polymer contains a polymeric group similarly to a polyfunctional monomer. Specifically, the thing of Paragraph No. [0080]-[0100] etc. in Unexamined-Japanese-Patent No. 2000-155216 specification are mentioned, for example.

The alignment film polymer may be crosslinked using a crosslinking agent separately from the crosslinkable functional group.

Crosslinking agents include aldehydes, N-methylol compounds, dioxane derivatives, compounds which act by activating carboxyl groups, active vinyl compounds, active halogen compounds, isoxazoles and dialdehyde starches. You may use together 2 or more types of crosslinking agents. Specifically, the compound etc. which were described in Paragraph No. [0023]-[0024] of Unexamined-Japanese-Patent No. 2002-62426 specification are mentioned, for example. Aldehydes having high reactive activity, in particular glutaraldehyde, are preferred.

0.1-20 mass% is preferable with respect to a polymer, and, as for the addition amount of a crosslinking agent, 0.5-15 mass% is more preferable. It is preferable that it is 1.0 mass% or less, and, as for the quantity of the unreacted crosslinking agent which remains in an oriented film, it is more preferable that it is 0.5 mass% or less. By this adjustment, even if the alignment film is left in the liquid crystal display for a long time or left for a long time in a high temperature and high humidity atmosphere, sufficient durability without reticulation is obtained.

The alignment film can be formed by applying a rubbing treatment on the transparent support including the polymer and the crosslinking agent, which is basically an alignment film forming material, followed by heat drying (crosslinking). The crosslinking reaction may be performed at any time after the coating on the transparent support as described above. In the case of using a water-soluble polymer such as polyvinyl alcohol as the alignment film forming material, it is preferable that the coating liquid is a mixed solvent of an organic solvent (eg, methanol) and water having a bubble removing effect. As for the ratio, as for mass ratio, water: methanol is 0-100-100: 1, and it is more preferable that it is 0-100-91: 9. For this reason, generation | occurrence | production of a bubble is suppressed and the defect of the surface of the layer of an oriented film and further an optically anisotropic layer is remarkably reduced.

The coating method of the alignment film is preferably a spin coating method, a dip coating method, a curtain coating method, an extrusion coating method, a rod coating method or a roll coating method. In particular, the rod coating method is preferable. Moreover, as for the film thickness after drying, 0.1-10 micrometers is preferable. Heat drying can be performed at 20 degreeC-110 degreeC. In order to form sufficient crosslinking, 60 to 100 degreeC is preferable, and 80 to 100 degreeC is especially preferable. Although drying time can be performed in 1 minute-36 hours, Preferably they are 1 minute-30 minutes. It is preferable to set it to the value suitable for the crosslinking agent which uses pH, and when glutaraldehyde is used, it is pH4.5-5.5, Especially 5 is preferable.

The alignment film can be formed on the surface of the transparent support or when the undercoat is formed on the transparent support as desired. The alignment film may be prepared by rubbing the surface after crosslinking the polymer layer as described above.

The rubbing treatment can be applied to a treatment method widely employed as a liquid crystal alignment treatment process for LCDs. That is, the method of obtaining an orientation by rubbing the surface of an oriented film in a fixed direction using paper, a gauze, a felt, rubber, nylon, polyester fiber, etc. can be used. Generally, rubbing is performed several times using a cloth or the like in which fibers having a uniform length and thickness are planted on average.

Next, the alignment film is functioned to align the liquid crystalline disk compound of the optically anisotropic layer formed on the alignment film. Thereafter, if necessary, the alignment film polymer and the polyfunctional monomer contained in the optically anisotropic layer may be reacted, or the alignment film polymer may be crosslinked using a crosslinking agent.

It is preferable that the film thickness of an oriented film exists in the range of 0.1-10 micrometers.

Moreover, it is also possible to form the said optically anisotropic layer directly on the surface of a polarizing film. Specifically, the optically anisotropic layer is formed by applying the above-mentioned coating liquid for optically anisotropic layer to the surface of the polarizing film. As a result, a thin polarizing plate with small stress (strain x cross-sectional area x elastic modulus) accompanying the dimensional change of the polarizing film is produced without using a polymer film between the polarizing film and the optically anisotropic layer. When the polarizing plate according to the first aspect of the present invention is attached to a large liquid crystal display device, an image with high display quality is displayed without causing problems such as light leakage.

[Polarizing Film]

The polarizing film which can be used for the 1st aspect of this invention is Optiva Inc. The coating type polarizing film represented by this, or the polarizing film which consists of a binder and iodine or a dichroic dye is preferable. Iodine and dichroic dye in the polarizing film exhibit deflection performance by being oriented in a binder. The iodine and the dichroic dye are preferably oriented along the binder molecule, or the dichroic dye is oriented in one direction by self-organization such as liquid crystal. Currently, commercially available polarizers are generally produced by immersing an elongated polymer in a solution of iodine or dichroic dye in a bath and infiltrating iodine or dichroic dye into a binder.

Commercially available polarizing films have iodine or dichroic pigments distributed on the surface of the polymer at about 4 μm (about 8 μm in total), and in order to obtain sufficient polarization performance, it is preferable to use a polarizing film having a thickness of 10 μm or more. Permeability can be controlled by the solution concentration of an iodine or dichroic dye, the temperature of the same bath, and the same immersion time.

As mentioned above, it is preferable that the minimum of binder thickness is 10 micrometers. The thinner the upper limit of the thickness, the better. It is preferable that it is currently commercially available polarizing plate (about 30 micrometers) or less, 25 micrometers or less are preferable, and 20 micrometers or less are more preferable. If it is 20 micrometers or less, a light leakage phenomenon will not be observed by a 17-inch liquid crystal display device.

The binder of the polarizing film may be crosslinked. As the crosslinked binder, a crosslinkable polymer may be used. The binder obtained by introducing a functional group into the polymer or polymer having a functional group can be reacted between the binders by light, heat or pH change to form a polarizing film. Moreover, you may introduce a crosslinked structure into a polymer with a crosslinking agent. Crosslinking is generally performed by apply | coating the coating liquid containing a polymer or a mixture of a polymer and a crosslinking agent on a transparent support body, and then heating. Since durability can be ensured at the final product stage, the crosslinking treatment can be performed at any stage until obtaining the final polarizing plate.

The binder of a polarizing film can use either the polymer itself crosslinkable, or the polymer crosslinked by a crosslinking agent. Examples of the polymer include the same polymers as those described for the alignment film. Most preferred are polyvinyl alcohol and modified polyvinyl alcohol. The modified polyvinyl alcohol is described in Japanese Unexamined Patent Publications Nos. 8-338913, 9-152509 and 9-316127. Polyvinyl alcohol and modified polyvinyl alcohol may use 2 or more types together.

As for the crosslinking agent addition amount of a binder, 0.1-20 mass% is preferable with respect to a binder. The orientation of a polarizing element and the moisture heat resistance of a polarizing film become favorable.

The alignment film contains a crosslinking agent that has not reacted to some extent even after the crosslinking reaction is completed. However, it is preferable that it is 1.0 mass% or less in an alignment film, and, as for the quantity of the remaining crosslinking agent, it is more preferable that it is 0.5 mass% or less. By doing so, even if the polarizing film is placed in a liquid crystal display device and left for a long time in a long-term use or a high temperature and high humidity atmosphere, the polarization degree is not lowered.

Crosslinking agents are described in the specification of US reissued patent 23297. In addition, boron compounds (eg, boric acid, borax) can also be used as the crosslinking agent.

As the dichroic dye, an azo dye, a stilbene dye, a pyrazolone dye, a triphenylmethane dye, a quinoline dye, an oxazine dye, a thiazine dye or an anthraquinone dye is used. It is preferable that a dichroic dye is water-soluble. The dichroic dye preferably has a hydrophilic substituent (eg, sulfo, amino, hydroxyl). As an example of a dichroic dye, the compound as described in the invention association open method, air number 2001-1745, page 58 (issue date March 15, 2001) is mentioned, for example.

In terms of yield, the polarizing film is preferably dyed with iodine or a dichroic dye after stretching the binder in the longitudinal direction (MD direction) of the polarizing film (stretching method) or rubbing (rubbing method).

In the stretching method, the stretching ratio is preferably 2.5 to 30.0 times, more preferably 3.0 to 10.0 times. Stretching can be performed by dry stretching in air. In addition, you may perform wet drawing in the state immersed in water. The stretching ratio of dry stretching is preferably 2.5 to 5.0 times, and the stretching ratio of wet stretching is preferably 3.0 to 10.0 times. An extending process may be divided into several times including diagonal stretch. By dividing into several times, it can extend | stretch more uniformly even in high magnification extending | stretching. Before extending | stretching, you may perform some extending | stretching (a grade which prevents contraction of the width direction) by the horizontal or longitudinal. Stretching can be performed by carrying out tenter stretching in biaxial stretching at different stages. The said biaxial stretching is the same as the extending method performed by normal film forming. In biaxial stretching, since the stretching is carried out at different speeds, the thickness of the binder film before stretching needs to be different from right to left. In flexible film forming, the taper is attached to the die so that the flow rate of the binder solution can be left or right.

In the rubbing method, a rubbing treatment method widely adopted as a liquid crystal alignment treatment process for LCDs can be applied. That is, the orientation is obtained by rubbing the surface of the film in a predetermined direction using paper, gauze, felt, rubber, nylon, or polyester fiber. Generally, it carries out by rubbing about several times using the cloth which averaged the fiber of uniform length and thickness. It is preferable to implement using the rubbing roll whose roundness, cylinder degree, and shake (eccentricity) of a roll itself are all 30 micrometers or less. As for the wrap angle of the film with respect to a rubbing roll, 0.1-90 degrees is preferable. However, as described in JP-A-8-160430, it is also possible to obtain stable rubbing treatment by winding 360 ° or more. When rubbing a long film, it is preferable to convey a film by the conveying apparatus at the speed of 1-100 m / min in the state of constant tension. It is preferable that the rubbing roll is freely rotated in the horizontal direction with respect to the film advancing direction in order to set an arbitrary rubbing angle. It is desirable to select an appropriate rubbing angle in the range of 0 to 60 degrees.

It is preferable that the polarizing plate which concerns on the 1st aspect of this invention is manufactured by a roll-to-roll system. In the roll-to-roll manufacturing method, for example, a long protective film wound in a roll shape and a long polarizing film wound in a roll shape are rewound in a roll shape while being successively laminated. Since it can manufacture continuously, it contributes to productivity improvement.

You may bond the laminated body (henceforth this laminated body also called an "optical compensation film") in which the said optically anisotropic layer was formed on the transparent support body (it is also a protective film) to one surface of a polarizing film. It is preferable that the surface bonded to a polarizing film is the back surface (surface of the side in which an optically anisotropic layer is not formed) of a transparent support body. An adhesive can be used at the time of joining. As the adhesive, a polyvinyl alcohol-based resin (including modified polyvinyl alcohol based on acetoacetyl group, sulfonic acid group, carboxyl group and oxyalkylene group) or boron compound aqueous solution can be used. Polyvinyl alcohol-type resin is preferable. The adhesive may be applied to the bonding surface of the polarizing film and / or the optical compensation film to form an adhesive layer, and both surfaces thereof may be laminated by heating or pressing as desired. It is preferable that the thickness of the said adhesive bond layer exists in the range of 0.01-10 micrometers after drying, and it is especially preferable to exist in the range which is 0.05-5 micrometers.

The optical compensation film and the polarizing film may also be laminated in a roll-to-roll manner.

On the other side of the polarizing film, a polymer film or the like which is a protective film is bonded. The polymer film is not particularly limited as long as the polymer film has a property capable of functioning as a protective film of the polarizing film. In addition, the polymer film is preferably formed by forming an antireflection film whose outermost surface has antifouling properties and scratch resistance. The antireflection film can be used any conventionally known.

In order to raise the contrast ratio of a liquid crystal display device, it is preferable that the transmittance | permeability of a polarizing plate is high, and it is preferable that a polarization degree is also high. The transmittance of the polarizing plate is preferably in the range of 30 to 50% for light having a wavelength of 550 nm, more preferably in the range of 35 to 50%, and most preferably in the range of 40 to 50%. The degree of polarization is preferably in the range of 90 to 100% for light having a wavelength of 550 nm, more preferably in the range of 95 to 100%, and most preferably in the range of 99 to 100%.

(2) Second aspect of the present invention

EMBODIMENT OF THE INVENTION Hereinafter, the action which concerns on the 2nd aspect of this invention is demonstrated using drawing.

3, the schematic diagram of the structural example of the liquid crystal display device which concerns on the 2nd aspect of this invention is shown. The liquid crystal display device of the TN mode shown in FIG. 3 is a liquid crystal cell composed of a liquid crystal layer 57 in which a liquid crystal bends to a substrate surface when a voltage is applied, that is, black, and both substrates 56 and 58. Has The substrates 56 and 58 are subjected to the alignment treatment on the liquid crystal surface, and the rubbing direction is indicated by an arrow RD. In the case of the back side, it is shown by the broken arrow. The polarizing films 51 and 61 are arrange | positioned by sandwiching a liquid crystal cell. The transmission axes 51a and 61a of each of the polarizing films 51 and 61 are arranged at right angles to each other and at an angle of 0 degrees or 90 degrees with the RD direction of the liquid crystal layer 57 of the liquid crystal cell. Between the polarizing films 51 and 61 and the liquid crystal cell, the transparent films 53 and 63 and the optically anisotropic layers 55 and 59 are arrange | positioned, respectively. The transparent films 53 and 63 are arrange | positioned in parallel with the direction of the transmission axis 51a and 61a of the polarizing films 51 and 61 whose slow axes 53a and 63a are adjacent, respectively. In addition, the optically anisotropic layers 55 and 59 have optical anisotropy expressed by the orientation of a liquid crystalline compound.

The liquid crystal cell of FIG. 3 has an upper substrate 56 and a lower substrate 58 and a liquid crystal layer formed of liquid crystal molecules 57 sandwiched therebetween. An alignment film (not shown) is formed on a surface (hereinafter also referred to as an "inner surface") in contact with the liquid crystal molecules 57 of the substrates 56 and 58, and the liquid crystal molecules 57 in a voltage-free state or a low applied state The orientation of is controlled in the parallel direction having a pretilt angle. Moreover, the transparent electrodes (not shown) which can apply a voltage to the liquid crystal layer which consists of liquid crystal molecules 57 are formed in the inner surface of the board | substrates 56 and 58. As shown in FIG. In the second aspect of the present invention, the product (Δn · d) of the thickness d (micron) and the refractive index anisotropy (Δn) of the liquid crystal layer is preferably 0.1 to 1.5 microns, more preferably 0.2 to 1.5 microns. More preferably 0.2 to 1.2 microns, even more preferably 0.6 to 0.9 microns. In these ranges, the white display luminance at the time of applying the white voltage is high, so that a bright and high contrast display device is obtained. Although there is no restriction | limiting in particular about the liquid crystal material to be used, In the aspect in which an electric field is applied between the upper and lower board | substrates 56 and 58, the liquid crystal material with positive dielectric anisotropy, such that the liquid crystal molecule 57 responds parallel to an electric field direction, is used. do.

For example, when making a liquid crystal cell into a TN mode liquid crystal cell, the nematic liquid crystal material etc. which have positive dielectric anisotropy and (DELTA) n = 0.08 and (DELTA) epsilon between the upper and lower substrates 56 and 58 can be used. Although it does not restrict | limit especially about the thickness d of a liquid crystal layer, When using the liquid crystal of the said range characteristic, it can set to about 6 micron. Since the brightness at the time of white display is changed by the thickness d and the product (Δn · d) of the refractive index anisotropy (Δn) at the time of application of the white voltage, in order to obtain sufficient brightness at the time of application of the white voltage, It is preferable to set Δn · d of the liquid crystal layer to be in a range of 0.6 to 1.5 microns.

In addition, in the liquid crystal display of the TN mode, a chiral material is sometimes added in order to reduce orientation defects. In addition, a multi-domain structure may be used in the TN mode. The multi-domain structure refers to a structure obtained by dividing one pixel of a liquid crystal display into a plurality of regions. For example, the multi-domain structure in the TN mode is preferable because the viewing angle characteristics of luminance and color tone are improved. Specifically, by constructing and averaging each pixel in two or more regions (preferably 4 or 8) in which the initial alignment states of liquid crystal molecules differ from each other, it is possible to reduce the deflection of luminance and color tone depending on the viewing angle. In addition, even when each pixel is composed of two or more different regions where the alignment direction of the liquid crystal molecules continuously changes in the voltage application state, the same effect is obtained.

In the transparent films 53 and 63, the ratio Re / Rth (450 nm) of Re and Rth at a wavelength of 450 nm is 0.39-0.95 times that of Re / Rth (550 nm) at a wavelength of 550 nm, and at a wavelength of 650 nm. Re / Rth (650 nm) satisfies the relationship of 1.04 to 2.20 times Re / Rth (550 nm), and Rth is 70 to 400 nm. The transparent films 53 and 63 may function as supports of the optically anisotropic layers 55 and 59, may function as protective films of the polarizing film 51 and the polarizing film 61, and have both functions. You may be. That is, the polarizing film 51, the transparent film 53, and the optically anisotropic layer 55, or the polarizing film 61, the transparent film 63, and the optically anisotropic layer 59 are integrated laminates inside the liquid crystal display device. May be contained, or may be contained as a single member, respectively. The protective film for the polarizing film may be separately disposed between the transparent film 53 and the polarizing film 51, or between the transparent film 63 and the polarizing film 61, but the protective film is preferably not disposed. . It is preferable that the slow axis 53a of the transparent film 53 and the slow axis 63a of the transparent film 63 are substantially parallel or orthogonal to each other. When the slow axes 53a and 63a of the transparent films 53 and 63 are orthogonal to each other, it is possible to reduce the deterioration in optical characteristics of light incident on the liquid crystal display by canceling the birefringence of each transparent film from each other. In the embodiment where the slow axes 53a and 63a are parallel to each other, when the liquid crystal layer has a residual phase difference, the phase difference can be compensated by birefringence of the protective film.

Materials used for each member regarding the transmission axes 51a and 61a of the polarizing films 51 and 61, the slow axis directions 53a and 63a of the transparent films 53 and 63, and the orientation direction of the liquid crystal molecules 57 The adjustment is made in an appropriate range depending on the display mode, the laminated structure of the members, and the like. That is, the transmission axis 51a of the polarizing film 51 and the transmission axis 61a of the polarizing film 61 are arranged so as to be substantially perpendicular to each other. However, the liquid crystal display device according to the second aspect of the present invention is not limited to this configuration.

The optically anisotropic layers 55 and 59 are disposed between the transparent films 53 and 63 and the liquid crystal cell. The optically anisotropic layers 55 and 59 are layers formed of a composition containing a liquid crystalline compound, for example, a rod-shaped compound or a disk-shaped compound. In the optically anisotropic layer, molecules of the liquid crystal compound are fixed in a predetermined alignment state. Orientation average direction 55a and 59a at the interface of the transparent film 53 and 63 side of the molecular symmetry axis of the liquid crystalline compound in the optically anisotropic layers 55 and 59, and the in-plane slow axis of the transparent films 53 and 63 53a and 63a intersect at about 0 degrees or about 90 degrees (the example which crossed 90 degrees in FIG. 3). When arranged in such a relationship, the optically anisotropic layer 55 or 59 does not generate retardation with respect to incident light from a normal direction, and does not generate light leakage, and it is the second invention of this invention about incident light from an oblique direction. The effect of an aspect can fully be exhibited. Also at the interface on the liquid crystal cell side, the orientation average direction of the molecular symmetry axes of the optically anisotropic layers 55 and 59 and the in-plane slow axes 53a and 63a of the transparent films 53 and 63 are preferably about 0 degrees or about 90 degrees. . In addition, the orientation average direction 55a of the polarizing film side (transparent film interface side) of the molecular symmetry axis of the liquid crystalline compound of the optically anisotropic layer 55 is weak with the transmission axis 51a of the polarizing film 51 located closer. It is preferable to arrange at 0 degree or about 90 degrees (in FIG. 3, 0 degree arrangement | positioning is shown). Similarly, the transmission axis 61a of the polarizing film 61 in which the orientation average direction 59a of the polarization film side (transparent film interface side) of the molecular symmetry axis | shaft of the liquid crystalline compound of the optically anisotropic layer 59 is located closer to it. It is preferable to arrange | position so that it may be about 0 degree or about 90 degree (In FIG. 3, the arrangement of 0 degree is shown). When arranged in such a relationship, light switching can be performed in accordance with the sum of the retardation generated by the optically anisotropic layer 55 or 59 and the retardation generated in the liquid crystal layer, and the incident light from the oblique direction can be viewed. The effects of the second aspect of the invention can be sufficiently exhibited.

Next, the image display principle of the liquid crystal display of FIG. 3 will be described.

In the driving state in which a driving voltage corresponding to black is applied to the transparent electrodes (not shown) of each of the liquid crystal cell substrates 56 and 58, the liquid crystal molecules 57 in the liquid crystal layer are more likely to stand on the liquid crystal molecules from the twist orientation in the initial state. The deformation is close to the state, and the polarization state of the incident light hardly changes in the front direction. Since the transmission axes 51a and 61a of the polarizing films 51 and 61 are orthogonal, the light incident from the lower side (for example, the back electrode) is polarized by the polarizing film 61 and the liquid crystal is maintained while maintaining the polarization state. It passes through the cells 55 to 58 and is blocked by the polarizing film 51. That is, in the liquid crystal display of Fig. 3, black display is realized in the driving state. On the other hand, in the driving state in which the driving voltage corresponding to the bag is applied to the transparent electrode (not shown), the liquid crystal molecules 57 in the liquid crystal layer are deformed close to the twisted alignment state, and the polarization plane of the incident light is the liquid crystal cell. By passing through it, it rotates about 90 degrees and passes through the polarizing film 51. In other words, a white display is obtained.

Conventionally, in TN mode, there existed a subject that even if the front contrast was high, it will fall in inclination direction. In Japanese Patent No. 2587398, in order to increase the visual contrast in the oblique direction, high contrast is obtained by compensating the liquid crystal cell and the optically anisotropic layer, but the transmission axes 51a and 61a of the upper and lower polarizing films 51 and 61 are obtained. Although the crossing angle is orthogonal to 90 degrees from the front, it is not sufficiently considered that the angle shifts from 90 degrees when viewed from the inclination. This causes a problem that leakage light occurs in the inclination direction and the contrast decreases. In the liquid crystal display device according to the second aspect of the present invention having the configuration shown in Fig. 3, attention is paid to this point of view, and the transparent film having the optical characteristics in which Re / Rth of R, G, and B do not coincide and satisfies specific conditions By using (53; or 63), light leakage in the oblique direction at the time of black display is reduced, and the contrast is improved.

More specifically, according to the second aspect of the present invention, by using the transparent film having the above optical properties, optical compensation of light having R, G, and B wavelengths incident in the oblique direction can be optically compensated with different slow axes and retardations for each wavelength. To make it possible. And in the optically anisotropic layer (55 and 59 in FIG. 3) which fixed the orientation of a liquid crystalline compound, the orientation average direction in the transparent film side interface of the symmetry axis of a liquid crystalline compound molecule, and the slow axis of a transparent film are 0 degree or 90 degrees. By arranging to cross the road, the unique compensation method of TN orientation can be performed in all wavelengths. As a result, the visual contrast of the black display is particularly improved, and the coloring in the visual direction of the black display is further reduced.

Here, in this specification, as wavelength of R, G, and B, R used wavelength 650 nm, G used wavelength 550 nm, and B used wavelength 450 nm. Although the wavelength of R, G, B is not necessarily represented by this wavelength, it is thought that it is a wavelength suitable for defining the optical characteristic which shows the effect of 2nd aspect of this invention.

In particular, in the second aspect of the present invention, attention was paid to Re / Rth which is the ratio of Re and Rth of the transparent film. This is because the value of Re / Rth determines the axes of two intrinsic polarizations in the light propagation propagating the birefringent medium in the oblique direction. The axes of the two intrinsic polarizations in the light propagation for advancing the birefringent medium in the oblique direction correspond to the major axis and minor axis of the cross section generated when the refractive index ellipsoid is cut in the normal direction of the light traveling direction. In Fig. 4, the direction of one axis of two intrinsic polarizations in the case where light traveling in the oblique direction is incident on the transparent film used in the second aspect of the present invention, that is, the angle of the slow axis and the Re / Rth in this case. An example of the result of having calculated the relationship of is shown. 4, it is assumed that the propagation direction of light is azimuth angle of 45 degrees and polar angle of 34 degrees. As shown in FIG. 4, the angle of the slow axis does not depend on the wavelength of incident light, and is uniquely determined by Re / Rth. How the polarization state of incident light changes by passing through the transparent film is mainly determined by the slow axis direction of the transparent film and the retardation of the transparent film. However, in the related art, regardless of the wavelengths of R, G, and B, Re / Rth The values of were almost the same, that is, the slow axis angles were almost the same. In contrast, in the second aspect of the present invention, by separately defining the relationship of Re / Rth for each of the wavelengths of R, G, and B, both the slow axis and the retardation, which are factors that mainly determine the change in polarization state, G and B are optimized for each wavelength. Then, when the light in the oblique direction through the transparent film passes the optically anisotropic layer fixing the alignment of the liquid crystal compound and passes the liquid crystal layer in the bend orientation again, the external transmission axis of the retardation and the vertical polarizing film is shifted from the front at any wavelength. In order to compensate for the two factors at the same time, the Re / Rth value of the transparent film is adjusted according to the wavelength. Specifically, the larger the wavelength, the greater the Re / Rth of the transparent film, thereby eliminating the difference in the polarization states in R, G, and B caused by the wavelength dispersion of the optically anisotropic layer and the liquid crystal cell layer. As a result, complete compensation was made possible and the fall of contrast was reduced. If the parameters of the film are defined by representing the entire area of visible light by R, G, and B, almost complete compensation can be achieved in the entire area of visible light.

Here the polar and azimuth angles are defined. The polar angle is the normal direction of the film surface, that is, the inclination angle from the z axis of FIG. 3, for example, the normal direction of the film surface is a direction in which the polar angle is 0 degrees. The azimuth represents the direction rotated counterclockwise with respect to the positive direction of the x axis. For example, the positive direction of the x axis is a direction in which the azimuth angle is 0 degrees, and the positive direction of the y axis is a direction in which the azimuth angle is 90 degrees. Since the polarization axis of the polarizing layer is ± 45, the inclination direction where the lack of light of black display is most problematic indicates mainly the case where the polar angle is not 0 degrees, and the azimuth angle is 0 degrees, 90 degrees, 180 degrees, and 270 degrees.

In order to demonstrate the effect | action of the 2nd aspect of this invention in more detail, the polarization state of the light which injected into the liquid crystal display device was shown on the Poincare sphere in FIG. In addition, in FIG. 5, the S2 axis | shaft is an axis | shaft penetrating vertically from the ground down, and FIG. 5 is the figure which looked at the Poincare sphere from the positive direction of S2 axis | shaft. In addition, since FIG. 5 shows planarly, the displacement of the point before and after a change of a polarization state is shown by the straight arrow in the figure, The change of the polarization state by actually passing through a liquid crystal layer or a transparent film is respectively carried out on Poincare sphere. It appears to rotate a certain angle around a particular axis, which is determined according to the optical properties of the.

In the conventional TN mode liquid crystal display device shown in FIG. 7, the transparent films 53 and 63 in which Re / Rth exhibits the wavelength dependency are not disposed, and instead, for example, the optical anisotropic layers 55 and 59 are transparent. The supports 73 and 83 are disposed. The transparent supports 73 and 83 are used for the purpose of supporting the optically anisotropic layers 55 and 59 and are made of a general polymer film. Therefore, there is no wavelength dependence on Re / Rth represented by the transparent films 53 and 63 used in the liquid crystal display of FIG. 3, and the same Re and Rth are shown at any wavelength of R, G, and B. FIG. As a result, in the conventional TN-mode liquid crystal display device, when the voltage is applied, that is, when the black display is performed, the front retardation of the liquid crystal cell and the optically anisotropic layer is canceled at the front, and even if black is obtained, there is a lack of light of the black display in the oblique direction. There was a problem that it was not completely suppressed. Moreover, as a result, sufficient visual contrast was not obtained, and since it could not compensate at all wavelengths, it had a coloring problem.

In FIG. 5, the polarization state of the incident light of R is IR, the polarization state of the incident light of G is represented by IB as the polarization state of the incident light of IG and B. In FIG. Further, in the conventional TN mode liquid crystal display device configuration, it is assumed that the transparent supports 73 and 83 in Fig. 7 are Re = 96 nm and Rth = 58 nm at any wavelength of R, G, and B, and the optically anisotropic layer 55 And 59) were calculated assuming Re = 30 nm. First, in FIG. 5, polarization states, IR1, IG1, and IB1 after passing through the polarizing film 61 are the same. When attention is paid to the change in the polarization state of the B light, it can be seen that the B light incident from the left 60 ° is shifted for each wavelength by passing the polarization state IB2 after passing through the transparent support 83 through the optically anisotropic layer 59. . As a result, the positions of the final transition states IR6, IG6 and IB6 of the R, G and B incident light do not coincide. Therefore, a phenomenon in which black is colored is generated because the lack of light of left and right blacks is not complete and sufficient visual contrast cannot be obtained, and light of all wavelengths cannot be blocked at the same time.

In the second aspect of the present invention, the visual contrast of the TN mode liquid crystal display device is improved by disposing a transparent film exhibiting specific optical characteristics. In order to explain in more detail, the result of calculating the polarization state of R, G, B light which passes through the TN mode liquid crystal display device shown in FIG. 3 is shown in the Poincare sphere of FIG. FIG. 6 is a diagram showing changes in polarization states of light incident from 60 ° below with respect to R, G, and B, respectively. In the figure, the polarization state of incident light of R is IR, and the polarization state of incident light of G is represented by IB. In addition, the transparent films 63 and 53 had a Re / Rth (450 nm) of 0.17 at a wavelength of 450 nm, a Re / Rth (550 nm) of 0.28 at a wavelength of 550 nm, and a Re / Rth of 650 nm at a wavelength of 650 nm. Nm) is 0.39, and it calculated on the assumption that Rth in wavelength 550nm is 160nm. Re of the optically anisotropic layers 55 and 59 was assumed to be the same value as the Poincare sphere shown in FIG. 5.

As shown in FIG. 6, the incident R light, G light, and B light pass through the transparent films 63 and 53, and then are all positioned at S1 = 0, and the Re / Rth of the transparent film 63 is measured. It reflects wavelength dependence and changes to the polarization state of the shifted position. This misalignment makes it possible to eliminate the misalignment of the polarization state that the R light, the G light and the B light receive due to the wavelength dispersion of the optically anisotropic layers 59, 55 and the liquid crystal layer 57. As a result, the light incident from any of the left and right directions can be made to have the same final transition point regardless of the wavelength. As a result, the lack of black light at the field of view can be reduced, and the contrast time can be greatly improved.

One of the features of the second aspect of the present invention is the use of the so-called biaxiality of the transparent film adjacent to the optically anisotropic layer to not only improve visual contrast in an oblique direction, for example, azimuth 270 degrees polar angle 60 degrees, but also the transparent film. By actively using the Re and Rth wavelength dispersion relations of the retardation, the lack of black light in the visual direction is improved. In particular, in the TN mode, by using an optical compensation film made of an optically anisotropic layer having a predetermined characteristic and a transparent film having a predetermined characteristic, visual contrast improvement in all directions is possible. The effect by this system is not limited to the display mode of a liquid crystal layer, It can be used also for the liquid crystal display device which has a liquid crystal layer of any display mode, such as TN mode, VA mode, IPS mode, ECB mode, and OCB mode.

In addition, the liquid crystal display device which concerns on the 2nd aspect of this invention is not limited to the structure shown in FIG. 3, and may contain the other member. For example, you may arrange a color filter between a liquid crystal cell and a polarizing film. In the case of using a transmission type, a backlight having a cold cathode or hot cathode fluorescent tube or a light emitting diode, a field emission element, or an electroluminescent element as a light source can be disposed on the rear surface.

The liquid crystal display device according to the second aspect of the present invention includes an image direct view type, an image projection type, and a light modulation type. The present invention is particularly effective when applied to an active matrix liquid crystal display device using a three-terminal or two-terminal semiconductor element such as a TFT or a MIM. Of course, the aspect applied to the passive matrix liquid crystal display device represented by STN type called time division drive is also effective.

Next, the member used in the liquid crystal display device according to the second aspect of the present invention will be described in more detail with respect to the optical properties, the raw material, the manufacturing method, and the like, particularly with respect to the optical compensation film according to the second aspect of the present invention. .

[Optical Compensation Film]

The optical compensation film according to the second aspect of the present invention contributes to the enlargement of the viewing angle contrast of the liquid crystal display device, especially the TN mode liquid crystal display device, and to the reduction of color shift depending on the viewing angle. The optical compensation film which concerns on the 2nd aspect of this invention may be arrange | positioned between the polarizing plate and liquid crystal cell of an observer side, may be arrange | positioned between the polarizing plate and liquid crystal cell of a back side, or may be arrange | positioned in both. For example, it may be placed inside the liquid crystal display device as an independent member, or may be imparted with optical properties to the protective film protecting the polarizing film to function as a transparent film, and may be placed inside the liquid crystal display device as one member of the polarizing plate. The optical compensation film according to the second aspect of the present invention has at least two layers of a transparent film and an optically anisotropic layer having optical anisotropy in the plane. You may have the orientation film which controls the liquid-crystal compound orientation in an optically anisotropic layer between a transparent film and an optically anisotropic layer. Moreover, as long as the optical characteristic mentioned later is satisfied, the transparent film and the optically anisotropic layer may consist of two or more layers, respectively. First, each structural member of the optical compensation film which concerns on the 2nd aspect of this invention is demonstrated in detail.

[Transparent film]

As for the transparent film which comprises the optical compensation film which concerns on the 2nd aspect of this invention, the ratio Re / Rth (450nm) of Re and Rth in wavelength 450nm of visible light region has Re / Rth (550nm) in wavelength 550nm. ) 0.39 to 0.95 times, preferably 0.39 to 0.9 times, more preferably 0.6 to 0.8 times, and Re / Rth (650 nm) at a wavelength of 650 nm is 1.04 to 2.20 of Re / Rth (550 nm). It is double, Preferably it is 1.1-1.9 times, More preferably, it is 1.2-1.7 times. In addition, it is preferable that Re / Rth in each of R, G, and B is all in the range of 0.1 to 0.8.

Moreover, since the retardation (Rth) of the thickness direction of the whole transparent film also has a function for canceling the retardation of the liquid crystal layer of the thickness direction at the time of black display, although a preferable range differs also by the aspect of each liquid crystal layer, Generally, it is preferable that Rth in wavelength 550nm is 70 nm-400 nm. More specifically, the liquid crystal cell of TN mode which has a liquid crystal layer whose product ((DELTA) n * d) of thickness d (micron) and refractive index anisotropy ((DELTA) n) is 0.2-1.5 micron, for example in TN mode When used for optical compensation of a cell), it is preferable that it is 10-200 nm, It is more preferable that it is 20 nm-150 nm, It is further more preferable that it is 40-120 nm. Moreover, Re retardation is generally 20-200 nm, Preferably it is 30-170 nm, More preferably, it is 80-130 nm.

The thickness of the transparent film is not particularly limited but is preferably 110 microns or less, preferably 40 to 110 microns, and more preferably 80 to 110 microns.

The transparent film can produce a transparent film that satisfies the optical properties of Re and Rth by selecting a raw material, its blending amount, manufacturing conditions, and adjusting the value thereof in a desired range. Specifically, a method of mixing two or more kinds of polymers having different wavelength dispersions, a method of controlling the wavelength dispersion of visible light by adding an additive having absorption in the ultraviolet or infrared range, and an additive having absorption in the ultraviolet or infrared range, Structurally orientated in the thickness direction, stretching direction or non-stretching direction of the film, coating or bonding polymers with different wavelength dispersion to adjust wavelength dispersion, nonuniform temperature distribution in the thickness direction in the film manufacturing process, or There is a method of controlling the wavelength dispersion by adjusting the orientation or the uniformity of the material by providing the intensity distribution of ultraviolet rays.

There is no restriction | limiting in particular about the raw material of the said transparent film. For example, a stretched birefringent polymer film may be sufficient, or the optically anisotropic layer formed by fixing a liquid crystalline compound in a specific orientation may be sufficient. The transparent film is not limited to a single layer structure but may have a laminated structure in which a plurality of layers are laminated. In the aspect of a laminated structure, the material of each layer may not be the same, for example, the laminated body of the optically anisotropic layer which consists of a polymer film and a liquid crystalline compound may be sufficient. In the aspect of a laminated structure, when thickness is considered, the coating type laminated body containing the layer formed by application | coating rather than the laminated body of a polymeric stretched film is preferable.

In the case where the liquid crystal compound is used for the production of the transparent film, the liquid crystal compound has various alignment forms, so that the optically anisotropic layer prepared by fixing the liquid crystal compound in a specific alignment state is formed by a single layer or by a multilayer of a plurality of layers. Express the desired optical properties. That is, the said transparent film may be an aspect which consists of a support body and the 1 or more optically anisotropic layer formed on this support body. The retardation of the whole transparent film of this aspect can be adjusted by the optical anisotropy of an optically anisotropic layer. A liquid crystalline compound can be classified into a rod-like liquid crystalline compound and a disk-shaped liquid crystalline compound from the shape of the molecule. Furthermore, there are low molecular and polymer types, respectively, and both can be used. When using a liquid crystalline compound for the production of the transparent film, it is preferable to use a rod-like liquid crystalline compound or a discotic liquid crystalline compound, and to use a rod-like liquid crystalline compound having a polymerizable group or a discotic liquid crystalline compound having a polymerizable group. It is more preferable.

In addition, the transparent film may be made of a polymer film. The polymer film may be a stretched polymer film, or may be a combination of a coating polymer layer and a polymer film. As the material of the polymer film, a synthetic polymer (eg, polycarbonate, polysulfone, polyethersulfone, polyacrylate, polymethacrylate, norbornene resin, triacetyl cellulose) is generally used. Moreover, the cellulose acylate type film which made into the film the composition which added the rod-shaped compound (specifically, aromatic compound which has two aromatic rings) which has an aromatic ring to cellulose acylate is also preferable. The polymer film which has desired optical characteristic can be produced by adjusting the kind, addition amount, and extending | stretching condition of a film of the said aromatic compound.

≪Cellulose acylate film≫

The cellulose acylate film which can be used as the transparent film will be described in more detail.

Optical properties of the transparent film by adjusting the type and amount of the rod-shaped compound having an aromatic ring to be added (specifically, an aromatic compound having two aromatic rings), or production conditions (for example, stretching conditions of the film). A cellulose acylate film which satisfies can be produced. Moreover, the protective film of a polarizing plate generally consists of a cellulose acylate film. When the cellulose acylate film is used as one protective film of the polarizing plate, an optical compensation function can be added to the polarizing plate without increasing the number of polarizing plate components.

In addition, when two or more types of rod-shaped compounds having a maximum absorption wavelength (λ max) of shorter wavelength than 250 nm are used in combination in the ultraviolet absorption spectrum, a Re / Rth ratio different according to the wavelength is obtained.

As the raw material side of the cellulose acylate, a known raw material may be used (see, for example, JP 2001-1745). Synthesis of cellulose acylate can also be carried out by known methods (see, for example, Migita et al., Pages 180-190 of wood chemistry (Gyoritsu Publication, 1968)). As for the viscosity average polymerization degree of a cellulose acylate, 200-700 are preferable, 250-500 are more preferable, 250-350 are the most preferable. Moreover, it is preferable that the cellulose acylate to be used has a narrow molecular weight distribution of Mw / Mn (Mw is mass average molecular weight and Mn is number average molecular weight) by gel permeation chromatography. As specific Mw / Mn value, it is preferable that it is 1.5-5.0, It is more preferable that it is 2.0-4.5, It is most preferable that it is 3.0-4.0.

Although the acyl group of this cellulose acylate film does not have a restriction | limiting in particular, It is preferable to use an acetyl group and a propionyl group, and especially an acetyl group is preferable. 2.7-3.0 are preferable and, as for the substitution degree of all acyl groups, 2.8-2.95 are more preferable. In the present specification, the degree of substitution of the acyl group is a value calculated according to ASTM D817. It is most preferable that an acyl group is an acetyl group, When using the cellulose acetate whose acyl group is an acetyl group, the acetylation degree is 59.0-62.5%, and its 59.0-61.5% is more preferable. When the acetylation degree is in this range, Re does not become larger than a desired value by conveyance tension at the time of casting | flow_spread, there are few in-plane deviations, and there are few changes of retardation value by temperature and humidity. In addition, the substitution degree of the acyl group at the 6th position is preferably 0.9 or more from the viewpoint of suppressing the gap between Re and Rth.

Moreover, wavelength dispersion characteristic can be adjusted using the thing which can adjust the wavelength-dispersion characteristic of retardation, if two kinds of cellulose acetates which mix acetylation degree in a fixed range are adjusted. This method is described in detail in Japanese Laid-Open Patent Publication No. 2001-253971, and the difference between the acetylation degree of cellulose acetate having the highest degree of acetylation (Ac1) and the cellulose acetate having the minimum degree of acetylation (Ac2) (Ac1- Ac2) is preferably 2.0 to 6.0% (2.0% ≤Ac1-Ac2≤6.0%). It is preferable that the average acetylation degree of the whole cellulose acetate mixture is 55.0-61.5%. Further, the ratio (P1 / P2) of the cellulose acetate having the maximum viscosity average degree of polymerization (P1) and the cellulose acetate having the minimum viscosity average degree of polymerization (P2) is not less than 1 but less than 2 (1 ≦ P1 / P2 < 2) is preferable. It is preferable that it is 250-500, and, as for the viscosity average polymerization degree of the whole cellulose acetate mixture, it is more preferable that it is 250-400.

≪Retardation control agent≫

It is preferable to contain the rod-shaped compound which has at least two aromatic ring in a cellulose acylate film as a retardation control agent. The rod-shaped compound preferably has a linear molecular structure. The linear molecular structure means that the molecular structure of the rod-shaped compound is linear in the thermodynamic most stable structure. The most thermodynamically stable structure can be obtained by crystal structure analysis or molecular orbital calculation. For example, the molecular orbital calculation software (for example, WinMOPAC2000, manufactured by Fujitsu Co., Ltd.) can be used to calculate the molecular orbital to obtain a molecular structure in which the generated heat of the compound is the smallest. The linear structure means that the angle constituting the main chain in the molecular structure is 140 degrees or more in the thermodynamic most stable structure calculated and calculated as described above.

As a rod-shaped compound which has at least two aromatic rings, the compound represented by following General formula (1) is preferable.

General formula (1): Ar ¹ -L ¹ -Ar ²

In the general formula (1), Ar ¹ and Ar ² are each independently an aromatic group, and L ¹ is a group consisting of an alkylene group, an alkenylene group, an alkynylene group, -O-, -CO- and combinations thereof Is the divalent linker of choice.

In the present specification, the aromatic group includes an aryl group (aromatic hydrocarbon group), a substituted aryl group, an aromatic heterocyclic group, and a substituted aromatic heterocyclic group.

An aryl group and a substituted aryl group are more preferable than an aromatic heterocyclic group and a substituted aromatic heterocyclic group. The heterocycle of the aromatic heterocyclic group is generally unsaturated. It is preferable that an aromatic hetero ring is a 5-membered ring, a 6-membered ring, or a 7-membered ring, and it is more preferable that it is a 5-membered ring or a 6-membered ring. Aromatic heterocycles generally have the largest number of double bonds. The hetero atom is preferably a nitrogen atom, an oxygen atom or a sulfur atom, and more preferably a nitrogen atom or a sulfur atom. Examples of aromatic hetero rings include furan ring, thiophene ring, pyrrole ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, pyrazole ring, furazane ring, triazole ring, pyran ring, pyridine ring and pyri Polyazine ring, pyrimidine ring, pyrazine ring, and 1,3,5-triazine ring are included.

As an aromatic ring of an aromatic group, a benzene ring, a furan ring, a thiophene ring, a pyrrole ring, an oxazole ring, a thiazole ring, imidazole ring, a triazole ring, a pyridine ring, a pyrimidine ring, and a pyrazine ring are preferable, and a benzene ring is especially preferable. .

Examples of the substituent of the substituted aryl group and the substituted aromatic heterocyclic group include halogen atom (F, Cl, Br, I), hydroxyl, carboxyl, cyano, amino, alkylamino group (e.g. methylamino, ethylamino, butylamino , Dimethylamino), nitro, sulfo, carbamoyl, alkylcarbamoyl groups (e.g., N-methylcarbamoyl, N-ethylcarbamoyl, N, N-dimethylcarbamoyl), sulfamoyl, alkylsulfamo Diaries (e.g., N-methylsulfamoyl, N-ethylsulfamoyl, N, N-dimethylsulfamoyl), ureido, alkylureido groups (e.g., N-methylureido, N, N-dimethylureido, N, N, N'-trimethylureido), alkyl group (e.g. methyl, ethyl, propyl, butyl, pentyl, heptyl, octyl, isopropyl, s-butyl, t-amyl, cyclohexyl, cyclopentyl), alkenyl group (e.g. , Vinyl, allyl, hexenyl), alkynyl groups (e.g. ethynyl, butynyl), acyl groups (e.g. formyl, acetyl, butyryl, hexanoyl, lauryl), acyloxy groups (e.g. acetoxy, part Aryloxy, hexanoyloxy, lauryloxy), alkoxy groups (e.g. methoxy, ethoxy, propoxy, butoxy, pentyloxy, heptyloxy, octyl oxy), aryloxy groups (e.g. phenoxy), alkoxy Carbonyl groups (e.g. methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, pentyloxycarbonyl, heptyloxycarbonyl), aryloxycarbonyl groups (e.g. phenoxycarbonyl), alkoxycarbonyl Amino groups (e.g. butoxycarbonylamino, hexyloxycarbonylamino), alkylthio groups (e.g. methylthio, ethylthio, propylthio, butylthio, pentylthio, heptylthio, octylthio), arylthio groups ( Phenylthio), alkylsulfonyl groups (e.g. methylsulfonyl, ethylsulfonyl, propylsulfonyl, butylsulfonyl, pentylsulfonyl, heptylsulfonyl, octylsulfonyl), amide groups (e.g. acetamide, butyl Amide groups, hexylamides, laurylamides) and non-aromatic heterocyclic groups (e.g., morpholine, La include possess).

Substituents of a substituted aryl group and a substituted aromatic heterocyclic group include halogen atom, cyano, carboxyl, hydroxyl, amino, alkyl substituted amino group, acyl group, acyloxy group, amide group, alkoxycarbonyl group, alkoxy group, alkylthio group And alkyl groups are preferred.

The alkyl portion and alkyl group of the alkylamino group, the alkoxycarbonyl group, the alkoxy group and the alkylthio group may further have a substituent. Examples of the alkyl moiety and the substituent of the alkyl group include halogen atom, hydroxyl, carboxyl, cyano, amino, alkylamino group, nitro, sulfo, carbamoyl, alkylcarbamoyl group, sulfamoyl, alkylsulfamoyl group, ureido, Alkyl ureido group, alkenyl group, alkynyl group, acyl group, acyloxy group, alkoxy group, aryloxy group, alkoxycarbonyl group, aryloxycarbonyl group, alkoxycarbonylamino group, alkylthio group, arylthio group, alkylsulfonyl group, amide group And non-aromatic heterocyclic groups. As the substituent of the alkyl moiety and the alkyl group, halogen atom, hydroxyl, amino, alkylamino group, acyl group, acyloxy group, acylamino group, alkoxycarbonyl group and alkoxy group are preferable.

L ¹ is a divalent linking group selected from a group consisting of an alkylene group, an alkenylene group, an alkynylene group, -O-, -CO-, and a combination thereof.

The alkylene group may have a cyclic structure. As the cyclic alkylene group, cyclohexylene is preferable, and 1,4-cyclohexylene is particularly preferable. As a linear alkylene group, a linear alkylene group is more preferable than a branched alkylene group.

It is preferable that the number of carbon atoms of an alkylene group is 1-20, More preferably, it is 1-15, More preferably, it is 1-10, More preferably, it is 1-8, Most preferably, it is 1-6. .

It is preferable that an alkenylene group and an alkynylene group have a linear structure rather than a cyclic structure, and it is more preferable to have a linear structure rather than the branched linear structure. The number of carbon atoms of the alkenylene group and the alkynylene group is preferably 2 to 10, more preferably 2 to 8, still more preferably 2 to 6, still more preferably 2 to 4, and most preferably Is 2 (vinylene or ethynylene). It is preferable that arylene group has 6-20 carbon atoms, More preferably, it is 6-16, More preferably, it is 6-12.

The example of the bivalent coupling group which consists of combinations is shown.

L-1: -O-CO-alkylene group-CO-O-

L-2: -CO-O-alkylene group-O-CO-

L-3: -O-CO-alkenylene group-CO-O-

L-4: -CO-O-alkenylene group-O-CO-

L-5: -O-CO-alkynylene group-CO-O-

L-6: -CO-O-alkynylene group-O-CO-

L-7: -O-CO-arylene group-CO-O-

L-8: -CO-O-arylene group-O-CO-

L-9: -O-CO-arylene group-CO-O-

L-10: -CO-O-arylene group-O-CO-

In the molecular structure of Formula (1), L ¹ Placed between the angle formed by the Ar ¹ and Ar ² is preferably not less than 140 degrees. As a rod-shaped compound, the compound represented by following General formula (2) is more preferable.

Formula (2): Ar ¹ -L ² -XL ³ -Ar ²

In the said General formula (2), Ar <^1> and Ar <^2> are respectively independently aromatic groups. Definitions and examples of the aromatic group are the same as those of Ar ¹ and Ar ² of the general formula (1).

In General formula (2), L <^2> and L <^3> is respectively independently the bivalent coupling group chosen from the group which consists of an alkylene group, -O-, -CO-, and its combination. It is preferable that an alkylene group has a linear structure rather than a cyclic structure, and it is more preferable to have a linear structure rather than the linear structure which has a branch.

The number of carbon atoms in the alkylene group is preferably 1 to 10, more preferably 1 to 8, still more preferably 1 to 6, still more preferably 1 to 4, and 1 or 2 (methylene or ethylene). Is most preferred. It is particularly preferable that L ² and L ³ are -O-CO- or CO-0-.

In General formula (2), X is 1, 4- cyclohexylene, vinylene, or ethynylene.

Below, the specific example of the compound represented by General formula (1) is shown.

Specific examples (1)-(34), (41), and (42) have two subtitle carbon atoms in the 1st and 4th positions of a cyclohexane ring. However, specific examples (1), (4) to (34), (41), and (42) have a symmetric meso-type molecular structure, so that there is no optical isomer (optical activity), and geometric isomers (trans and cis) Only). The trans form (1-trans) and cis form (1-cis) of the specific example (1) are shown below.

As described above, the rod-shaped compound preferably has a linear molecular structure. Therefore, a trans type is more preferable than a sheath type. Embodiments (2 and 3) have optical isomers (four kinds of isomers in total) in addition to geometric isomers. Similarly, for the geometric isomer, the trans form is more preferable than the cis form. The optical isomer is not particularly superior and may be any of D, L or racemate. In the specific examples (43)-(45), a trans type and a cis type exist in the center vinylene bond. For the same reasons as above, the trans type is more preferable than the cis type.

In addition, the preferable compound which can be used as a retardation control agent is shown below.

As a retardation control agent, it is preferable to use together two or more types of rod-shaped compounds whose maximum absorption wavelength ((lambda) max) is shorter than 250 nm in the ultraviolet absorption spectrum of a solution. Rod-shaped compounds can be synthesized with reference to the methods described in the literature. Literature includes Mol. Cryst. Liq. Cryst., Vol. 53, p. 229 (1979), v. 89, p. 93 (1982), v. 145, p. 111 (1987), v. 170, p. 43 (1989), J. Am. Chem. Soc., Vol. 113, p. 1349 (1991), vol.118, p. 5346 (1996), vol. 92, p. 1582 (1970), J. Org. Chem., 40, 420 (1975), Tetrahedron, 48, 16, 3437 (1992).

It is preferable that it is 0.1-30 mass% of a polymer amount, and, as for the addition amount of a retardation control agent, it is more preferable that it is 0.5-20 mass%.

An aromatic compound is used in 0.01-20 mass parts with respect to 100 mass parts of cellulose acylates. It is preferable to use an aromatic compound in 0.05-15 mass parts with respect to 100 mass parts of cellulose acylate, and it is more preferable to use in 0.1-10 mass parts. You may use together 2 or more types of compounds.

Wavelength dispersion regulator

The compound which adjusts the wavelength dispersion of a cellulose acylate film is demonstrated. The wavelength dispersion property of a cellulose acylate film can be adjusted by various methods. For example, it can adjust by containing in a film the compound which has absorption in the ultraviolet region of 200-400 nm. Although the preferable addition amount of this compound changes with the kind and adjustment of the compound to be used, the cellulose acylate film which has the optical characteristic calculated | required by the said transparent film about 0.01-30 mass% can be produced.

Re and Rth values of a cellulose acylate film generally have a wavelength dispersion characteristic in which the long wavelength side is larger than the short wavelength side. Therefore, the wavelength dispersion can be smoothed by increasing Re and Rth on the relatively short wavelength side. On the other hand, a compound having absorption in the ultraviolet region of 200 to 400 nm has a wavelength dispersion characteristic in which the absorbance at the long wavelength side is larger than the short wavelength side. When the compound itself is isotropically present inside the cellulose acylate film, it is assumed that the birefringence of the compound itself, and further, the Re and Rth wavelength dispersions are large in the short wavelength side similarly to the wavelength dispersion of the absorbance.

Therefore, Re and Rth wavelength dispersion of a cellulose acylate film are prepared by using what has absorption in the ultraviolet region of 200-400 nm mentioned above, and is assumed that Re and Rth wavelength dispersion of a compound itself are large in short wavelength side. can do. For this purpose, it is required that the compound for adjusting the wavelength dispersion is sufficiently uniformly dissolved in the cellulose acylate. The absorption band range of the ultraviolet region of such a compound is preferably 200 to 400 nm, more preferably 220 to 395 nm and even more preferably 240 to 390 nm.

In recent years, in liquid crystal display devices such as televisions, notebook computers, and mobile portable terminals, in order to increase luminance with less power, it is required to have excellent transmittance of the optical member used in the liquid crystal display device. In that respect, when a compound having absorption in the ultraviolet region of 200 to 400 nm is added to the cellulose acylate film, excellent spectral transmittance is required. In the said cellulose acylate film, it is preferable that the spectral transmittances in wavelength 380nm are 45% or more and 95% or less, and the spectral transmittances in wavelength 350nm are 10% or less.

The wavelength dispersion regulator preferably used in this embodiment as described above preferably has a molecular weight of 250 to 1000 from the viewpoint of volatilization. More preferably, it is 260-800, More preferably, it is 270-800, Especially preferably, it is 300-800. If it is these molecular weight ranges, a specific monomer structure may be sufficient and the oligomer structure and polymer structure which the monomer unit couple | bonded two or more may be sufficient.

It is preferable that the wavelength dispersion regulator is not volatilized during the dope softening and drying of the cellulose acylate film.

(Compound addition amount)

As mentioned above, it is preferable that the addition amount of the wavelength dispersion tank tablet used preferably in this aspect is 0.01-30 mass% of cellulose acylate, It is more preferable that it is 0.1-20 mass%, It is 0.2-10 mass Particular preference is given to%.

(Compound addition method)

In addition, these wavelength dispersion regulators may be used independently, or may mix and use 2 or more types of compounds by arbitrary ratios.

In addition, the time of adding these wavelength dispersion regulators may be any time in a dope preparation process, and may be performed last of a dope preparation process.

As a specific example of the wavelength-dispersion adjusting agent suitably used in this embodiment, for example, a benzotriazole compound, a benzophenone compound, a compound containing a cyano group, an oxybenzophenone compound, a salicylic acid ester compound, a nickel complex salt compound Although these etc. are mentioned, it is not limited only to the compound used for this aspect.

As a benzotriazole type compound, what is represented by General formula (3) is used suitably as a wavelength-dispersion regulator.

General formula (3)

Q ¹ -Q ² -OH

(Wherein, Q ¹ represents a nitrogen-containing aromatic heterocycle, Q ² represents an aromatic ring)

Q ¹ represents a nitrogen-containing aromatic heterocycle, preferably a 5- to 7-membered nitrogen-aromatic heterocycle, more preferably a 5- to 6-membered nitrogen-aromatic heterocycle, for example, imidazole, pyra Sol, triazole, tetrazole, thiazole, oxazole, selenazole, benzotriazole, benzothiazole, benzoxazole, benzo selenazole, thiadiazole, oxadiazole, naphthothiazole, naphthooxazole, Azabenzimidazole, purine, pyridine, pyrazine, pyrimidine, pyridazine, triazine, triazaindene, tetrazaindene, and the like, more preferably a 5-membered nitrogen-aromatic heterocycle, and specifically Is preferably imidazole, pyrazole, triazole, tetrazole, thiazole, oxazole, benzotriazole, benzothiazole, benzoxazole, thiadiazole, oxadiazole, and particularly preferably benzotriazole. . The nitrogen-containing aromatic aromatic ring represented by Q ¹ may further have a substituent, and the substituent T described later may be applied as the substituent. In addition, when there are a plurality of substituents, each may be condensed to further form a ring.

The aromatic ring represented by Q ² may be an aromatic hydrocarbon ring or an aromatic hetero ring. In addition, these may be mono-cyclic and may further form a condensed ring with another ring. As an aromatic hydrocarbon ring, Preferably it is a C6-C30 monocyclic or 2 ring aromatic hydrocarbon ring (for example, a benzene ring, a naphthalene ring etc.), More preferably, it is a C6-C20 aromatic hydrocarbon ring, More preferably, It is a C6-C12 aromatic hydrocarbon ring, More preferably, it is a benzene ring.

The aromatic hetero ring is preferably an aromatic hetero ring containing a nitrogen atom or a sulfur atom. Specific examples of the heterocycle include, for example, thiophene, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, indazole, purine, thiazolin, thiazole, thiadiazole, Oxazoline, oxazole, oxadiazole, quinoline, isoquinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, acridine, phenanthroline, phenazine, tetrazole, benz Imidazole, benzoxazole, benzthiazole, benzotriazole, tetrazaindene, etc. are mentioned. As an aromatic heterocyclic ring, Preferably, they are pyridine, triazine, quinoline. The aromatic ring represented by Q ² is preferably an aromatic hydrocarbon ring, more preferably a naphthalene ring or a benzene ring, and particularly preferably a benzene ring. Q ² may further have a substituent, and substituent T described later is preferable. The substituent T is, for example, an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, for example, methyl, ethyl, iso-propyl, tert-butyl). , n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc., alkenyl group (preferably carbon 2-20, more preferably carbon 2-12, particularly preferably carbon number) 2 to 8, for example, vinyl, allyl, 2-butenyl, 3-pentenyl, and the like, alkynyl group (preferably 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably carbon) 2 to 8, for example, propargyl, 3-pentynyl, and the like, an aryl group (preferably 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms), For example, phenyl, p-methylphenyl, naphthyl and the like, a substituted or unsubstituted amino group (preferably 0 carbon atoms) -20, More preferably, it is C0-C10, Especially preferably, it is C6-C6, For example, amino, methylamino, dimethylamino, diethylamino, dibenzylamino etc., an alkoxy group (preferably C1-C20, More preferably, it is C1-C12, Especially preferably, it is C1-C8, For example, Methoxy, ethoxy, Butoxy etc., An aryloxy group (preferably C6-C20) More preferably, they are C6-C16, Especially preferably, it is C6-C12, For example, Phenyloxy, 2-naphthyloxy, etc., Acyl group (Preferably C1-C20, More preferably, C1-C16, Especially preferably, it is C1-C12, For example, acetyl, benzoyl, formyl, pivaloyl, etc., Alkoxycarbonyl group (Preferably C2-C20, More preferably, C2-C20) 16, Especially preferably, it is C2-C12, For example, methox Carbonyl, ethoxycarbonyl and the like, and an aryloxycarbonyl group (preferably having 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 10 carbon atoms), for example, phenyloxycarbonyl and the like. ), Acyloxy group (preferably 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, for example, acetoxy, benzoyloxy, etc.), acylamino group (preferably Is C2-C20, More preferably, it is C2-C16, Especially preferably, it is C2-C10, For example, acetylamino, benzoylamino etc., Alkoxycarbonylamino group (Preferably C2-C20, More preferably, it is C2-C16, Especially preferably, it is C2-C12, For example, a methoxycarbonylamino etc., An aryloxycarbonylamino group (Preferably C7-20, More preferably, carbon number) 7 to 16, Especially preferably, it is C7-C12, for example, phenyloxycarbonylamino etc., sulfonylamino group (preferably C1-C20, More preferably, C1-C16, Especially preferably, C1-C12 12, for example, methanesulfonylamino, benzenesulfonylamino, and the like, sulfamoyl group (preferably having 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, particularly preferably 0 to 12 carbon atoms, For example, sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, phenylsulfamoyl, etc., carbamoyl groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 1 carbon atoms). 12, for example, carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl, etc., an alkylthio group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms); Especially preferably, it is C1-C12, For example, Eh, methylthio, ethylthio, etc.), an arylthio group (preferably C6-C20, more preferably C6-C16, especially preferably C6-C12, for example, phenylthio, etc.), Sulfonyl groups (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, for example, mesyl, tosyl, etc.) and sulfinyl groups (preferably 1 to 20 carbon atoms). More preferably, they are C1-C16, Especially preferably, it is C1-C12, For example, methanesulfinyl, benzenesulfinyl, etc., A ureido group (Preferably C1-C20, More preferably, C1-C12) 1-16, Especially preferably, it is C1-C12, For example, ureido, methylureido, phenylureido, etc., phosphate amide group (preferably C1-C20, More preferably, C1-C12) 16, Especially preferably, it is C1-C12, For example, die Yl phosphate amide, phenyl phosphate amide, etc.), hydroxy group, mercapto group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid Group, sulfino group, hydrazino group, imino group, heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and as a hetero atom, for example, a nitrogen atom, an oxygen atom, a sulfur atom, specifically Examples include, for example, imidazolyl, pyridyl, quinolyl, furyl, piperidyl, morpholino, benzooxazolyl, benzimidazolyl, benzti azolyl, and silyl groups (preferably having 3 to 3 carbon atoms). 40, More preferably, it is C3-C30, Especially preferably, it is C3-C24, For example, trimethylsilyl, triphenylsilyl, etc.) etc. are mentioned. These substituents may further be substituted. In addition, when there are two or more substituents, they may be same or different. In addition, when possible, you may connect with each other and form a ring.

Among the compounds represented by the general formula (3), compounds represented by the following general formula (3-A) are preferable.

General formula (3-A)

In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ each independently represent a hydrogen atom or a substituent.

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ each independently represent a hydrogen atom or a substituent, and the substituent T described above can be applied as the substituent. In addition, these substituents may be further substituted by another substituent, and substituents may be condensed and may form ring structure.

R ¹ and R ³ are preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxy group, a halogen atom, more preferably a hydrogen atom, It is an alkyl group, an aryl group, an alkyloxy group, an aryloxy group, and a halogen atom, More preferably, it is a hydrogen atom and a C1-C12 alkyl group, Especially preferably, it is a C1-C12 alkyl group (preferably C4-C12) to be.

R ² and R ⁴ are preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxy group, a halogen atom, more preferably a hydrogen atom, It is an alkyl group, an aryl group, an alkyloxy group, an aryloxy group, a halogen atom, More preferably, it is a hydrogen atom, a C1-C12 alkyl group, Especially preferably, it is a hydrogen atom, a methyl group, Most preferably, it is a hydrogen atom.

R ⁵ and R ⁸ are preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxy group, a halogen atom, more preferably a hydrogen atom, It is an alkyl group, an aryl group, an alkyloxy group, an aryloxy group, a halogen atom, More preferably, it is a hydrogen atom, a C1-C12 alkyl group, Especially preferably, it is a hydrogen atom, a methyl group, Most preferably, it is a hydrogen atom.

R ⁶ and R ⁷ are preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxy group, a halogen atom, more preferably a hydrogen atom, It is an alkyl group, an aryl group, an alkyloxy group, an aryloxy group, and a halogen atom, More preferably, they are a hydrogen atom and a halogen atom, Especially preferably, they are a hydrogen atom and a chlorine atom.

In general formula (3), it is more preferably a compound represented by the following general formula (3-B).

General formula (3-B)

In formula, R <^1> , R <^3> , R <^6> and R <^7> are synonymous with those in general formula (3-A), and its preferable range is also the same.

Although the specific example of a compound represented by General formula (3) below is given, this invention is not limited to the following specific example at all.

As mentioned above, when the said cellulose acylate film was produced without including the thing whose molecular weight is 320 or less among the benzotriazole type compounds quoted above, it was confirmed that it was advantageous at the point of retention.

Moreover, as a benzophenone type compound which is one of the wavelength dispersion regulators used for the 2nd aspect of this invention, what is represented by General formula (4) is used preferably.

General formula (4)

In the formula, Q ^1a and Q ^2a each independently represent an aromatic ring. X represents NR (R represents a water element or a substituent), an oxygen atom or a sulfur atom.

The aromatic ring represented by Q ^1a and Q ^2a may be an aromatic hydrocarbon ring or an aromatic hetero ring. In addition, these may be mono-cyclic and may further form a condensed ring with another ring. The aromatic hydrocarbon ring represented by Q ^1a and Q ^2a is preferably (preferably a monocyclic or bicyclic aromatic hydrocarbon ring having 6 to 30 carbon atoms (for example, a benzene ring, a naphthalene ring, etc.), and more preferably. Is a C6-C20 aromatic hydrocarbon ring, More preferably, it is a C6-C12 aromatic hydrocarbon ring. More preferably, it is a benzene ring. The aromatic heterocycle represented by Q ^1a and Q ^2a is preferably an aromatic heterocycle including at least one of an oxygen atom, a nitrogen atom or a sulfur atom. Specific examples of heterocycles include, for example, furan, pyrrole, thiophene, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, indazole, purine, thiazolin, thiazole, Thiadiazole, oxazoline, oxazole, oxadiazole, quinoline, isoquinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, acridine, phenanthroline, phenazine, Tetrazole, benzimidazole, benzoxazole, benzthiazole, benzotriazole, tetrazaindene and the like. As an aromatic heterocyclic ring, Preferably, they are pyridine, triazine, quinoline. The aromatic ring represented by Q ^1a and Q ^2a is preferably an aromatic hydrocarbon ring, more preferably an aromatic hydrocarbon ring having 6 to 10 carbon atoms, still more preferably a substituted or unsubstituted benzene ring. Q ^1a and Q ^2a may further have a substituent, and substituent T described later is preferable, but the substituent does not contain carboxylic acid, sulfonic acid or quaternary ammonium salt. In addition, when possible, substituents may connect and form a ring structure.

X represents NR (R represents a hydrogen atom or a substituent. The substituent T mentioned later can be applied), an oxygen atom, or a sulfur atom, and X represents preferably NR (preferably an acyl group, It is a sulfonyl group, These substituents may further substitute), or O, Especially preferably, it is O.

The substituent T is, for example, an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, for example methyl, ethyl, iso-propyl, tert-butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), alkenyl group (preferably 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably 2 carbon atoms) It is -8, for example, vinyl, allyl, 2-butenyl, 3-pentenyl, etc., an alkynyl group (preferably C2-C20, More preferably, it is C2-C12, Especially preferably, it is C2-C) 8, for example propargyl, 3-pentynyl, and the like, an aryl group (preferably 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms), for example Phenyl, p-methylphenyl, naphthyl and the like, and a substituted or unsubstituted amino group (preferably having 0 to 0 carbon atoms). 20, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, for example, amino, methylamino, dimethylamino, diethylamino, dibenzylamino, etc., an alkoxy group (preferably C1) It is -20, More preferably, it is C1-C12, Especially preferably, it is C1-C8, For example, methoxy, ethoxy, butoxy, etc., An aryloxy group (preferably C6-C20, More preferable) Preferably it is C6-C16, Especially preferably, it is C6-C12, For example, phenyloxy, 2-naphthyloxy, etc., Acyl group (Preferably C1-C20, More preferably, C1-C16 , Particularly preferably 1 to 12 carbon atoms, for example, acetyl, benzoyl, formyl, pivaloyl and the like, alkoxycarbonyl group (preferably 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms), particularly preferably Is 2 to 12 carbon atoms, for example, methoxycarb And aryloxycarbonyl groups (preferably having 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 10 carbon atoms, for example, phenyloxycarbonyl); Acyloxy group (preferably C2-C20, More preferably, it is C2-C16, Especially preferably, it is C2-C10, For example, acetoxy, benzoyloxy etc.), Acylamino group (Preferably C2-C2) It is -20, More preferably, it is C2-C16, Especially preferably, it is C2-C10, For example, acetylamino, benzoylamino, etc., The alkoxycarbonylamino group (Preferably C2-C20, More preferably C2-C16, Especially preferably, it is C2-C12, For example, methoxycarbonylamino etc., An aryloxycarbonylamino group (Preferably C7-20, More preferably, C7-16, Especially bar It is preferably 7 to 12 carbon atoms, for example, phenyloxycarbonylamino or the like, a sulfonylamino group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms). For example, methanesulfonylamino, benzenesulfonylamino, etc., sulfamoyl group (preferably C0-20, More preferably, it is C0-16, Especially preferably, it is C12-12, for example, Sulfamoyl, methyl sulfamoyl, dimethyl sulfamoyl, phenyl sulfamoyl, etc., carbamoyl groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms). For example, carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl and the like, alkylthio group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 carbon atom). It is -12, for example, methylthio , Ethylthio, etc.), an arylthio group (preferably 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, for example, phenylthio, etc.), a sulfonyl group (preferably Is C1-C20, More preferably, it is C1-C16, Especially preferably, it is C1-C12, For example, mesyl, tosyl, etc., A sulfinyl group (preferably C1-C20, More preferably, C1-C20) 1-16, Especially preferably, it is C1-C12, For example, methanesulfinyl, benzenesulfinyl, etc., A ureido group (Preferably C1-C20, More preferably, C1-C16, Especially preferably, Is C1-C12, for example, ureido, methylureido, phenylureido, etc., a phosphate amide group (preferably C1-C20, More preferably, C1-C16, Especially preferably, C1-C1) -12, for example, diethyl phosphate amide, pe Nylphosphate amide), hydroxy group, mercapto group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group , A hydrazino group, an imino group, a heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and as a hetero atom, for example, a nitrogen atom, an oxygen atom, a sulfur atom, and specifically, for example, Dazolyl, pyridyl, quinolyl, furyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, etc.), silyl group (preferably carbon number 3-40, more preferably carbon number) 3-30, Especially preferably, it is C3-C24, For example, trimethylsilyl, triphenylsilyl, etc. are mentioned. These substituents may further be substituted. In addition, when there are two or more substituents, they may be same or different. In addition, when possible, you may connect with each other and form a ring.

In general formula (4), it is a compound preferably represented by the following general formula (4-A).

General formula (4-A)

In the formula, R ^1b , R ^2b , R ^3b , R ^4b , R ^5b , R ^6b , R ^7b , R ^8b and R ^9b each independently represent a hydrogen atom or a substituent.

R ^1b , R ^2b , R ^3b , R ^4b , R ^5b , R ^6b , R ^7b , R ^8b and R ^9b each independently represent a hydrogen atom or a substituent, and the substituent T described above may be applied as the substituent. . In addition, these substituents may be further substituted by another substituent, and substituents may be condensed and may form ring structure.

R ^1b , R ^2b , R ^3b , R ^4b , R ^5b , R ^6b , R ^7b , R ^8b and R ^9b are preferably hydrogen atoms, alkyl groups, alkenyl groups, alkynyl groups, aryl groups, substituted or unsubstituted amino groups , An alkoxy group, an aryloxy group, a hydroxy group, a halogen atom, more preferably a hydrogen atom, an alkyl group, an aryl group, an alkyloxy group, an aryloxy group, a halogen atom, more preferably a hydrogen atom, a carbon 1-12 alkyl group Especially preferably, they are a hydrogen atom and a methyl group, Most preferably, they are a hydrogen atom.

R ^2b is preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxy group, a halogen atom, more preferably a hydrogen atom, 1 to 20 carbon atoms. It is an alkyl group, a C0-20 amino group, a C1-C12 alkoxy group, a C6-C12 aryloxy group, and a hydroxyl group, More preferably, it is a C1-C20 alkoxy group, Especially preferably, it is C1-C12 Is an alkoxy group.

R ^7b is preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxy group, a halogen atom, more preferably a hydrogen atom, 1 to 20 carbon atoms. It is an alkyl group, a C0-20 amino group, a C1-C12 alkoxy group, a C6-C12 aryloxy group, and a hydroxy group, More preferably, it is a hydrogen atom and a C1-C20 alkyl group (preferably C1-C12). More preferably, they are C1-C8, More preferably, they are a methyl group, Especially preferably, they are a methyl group and a hydrogen atom.

As general formula (4), It is a compound represented by following General formula (4-B) more preferably.

General formula (19-B)

In the formula, R ^10b represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aryl group.

R ^10b represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aryl group, and the substituents T described above can be applied as a substituent. have.

R ^10b is preferably a substituted or unsubstituted alkyl group, more preferably a substituted or unsubstituted alkyl group having 5 to 20 carbon atoms, and even more preferably a substituted or unsubstituted alkyl group having 5 to 12 carbon atoms (n-hex). The actual group, 2-ethylhexyl group, n-octyl group, n-decyl group, n-dodecyl group, benzyl group, etc. are mentioned, Especially preferably, a C6-C12 substituted or unsubstituted alkyl group (2 -Ethylhexyl group, n-octyl group, n-decyl group, n-dodecyl group, benzyl group).

The compound represented by General formula (4) can be synthesize | combined by the well-known method of Unexamined-Japanese-Patent No. 11-12219.

Although the specific example of a compound represented by General formula (4) below is given, this invention is not limited to the following specific example at all.

Moreover, as a compound containing the cyano group which is one of the wavelength dispersion regulators used for the 2nd aspect of this invention, what is represented by General formula (5) is used preferably.

General formula (5)

In the formulas, Q ^1c and Q ^2c each independently represent an aromatic ring. X ^1c and X ^2c Represents a hydrogen atom or a substituent, and at least one represents a cyano group, a carbonyl group, a sulfonyl group, or an aromatic heterocycle. The aromatic ring represented by Q ^1c and Q ^2c may be an aromatic hydrocarbon ring or an aromatic hetero ring. In addition, these may be mono-cyclic and may further form a condensed ring with another ring.

As aromatic hydrocarbon ring, Preferably it is (C6-C30 monocyclic or 2 ring aromatic hydrocarbon ring (for example, benzene ring, naphthalene ring etc.), More preferably, C6-C20 aromatic hydrocarbon ring, More Preferably it is a C6-C12 aromatic hydrocarbon ring.) More preferably, it is a benzene ring.

As an aromatic hetero ring, Preferably, it is an aromatic hetero ring containing a nitrogen atom or a sulfur atom. Specific examples of the heterocycle include, for example, thiophene, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, indazole, purine, thiazolin, thiazole, thiadiazole, Oxazoline, oxazole, oxadiazole, quinoline, isoquinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, acridine, phenanthroline, phenazine, tetrazole, benz Imidazole, benzoxazole, benzthiazole, benzotriazole, tetrazaindene, etc. are mentioned. As an aromatic heterocyclic ring, Preferably, they are pyridine, triazine, quinoline.

The aromatic ring represented by Q ^1c and Q ^2c is preferably an aromatic hydrocarbon ring, more preferably a benzene ring. Q ^1c and Q ^2c May further have a substituent, and substituent T described later is preferable. The substituent T is, for example, an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, for example methyl, ethyl, iso-propyl, tert-butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), alkenyl group (preferably 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably 2 to 8, for example, vinyl, allyl, 2-butenyl, 3-pentenyl, and the like, alkynyl group (preferably 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably 2 carbon atoms). It is -8, for example, propargyl, 3-pentynyl, etc., an aryl group (preferably C6-C30, More preferably, it is C6-C20, Especially preferably, it is C6-C12, For example, For example, phenyl, p-methylphenyl, naphthyl, etc., a substituted or unsubstituted amino group (preferably 0 to 20, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, for example, amino, methylamino, dimethylamino, diethylamino, dibenzylamino, etc., an alkoxy group (preferably C1) It is -20, More preferably, it is C1-C12, Especially preferably, it is C1-C8, For example, methoxy, ethoxy, butoxy, etc., An aryloxy group (preferably C6-C20, More preferable) Preferably it is C6-C16, Especially preferably, it is C6-C12, For example, phenyloxy, 2-naphthyloxy, etc., Acyl group (Preferably C1-C20, More preferably, C1-C16 , Particularly preferably 1 to 12 carbon atoms, for example, acetyl, benzoyl, formyl, pivaloyl and the like, alkoxycarbonyl group (preferably 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms), particularly preferably Is 2 to 12 carbon atoms, for example, methoxycarb And aryloxycarbonyl groups (preferably having 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 10 carbon atoms, for example, phenyloxycarbonyl); Acyloxy group (preferably C2-C20, More preferably, it is C2-C16, Especially preferably, it is C2-C10, For example, acetoxy, benzoyloxy etc.), Acylamino group (Preferably carbon number 2-20, More preferably, it is C2-C16, Especially preferably, it is C2-C10, For example, acetylamino, Benzoylamino, etc., The alkoxycarbonylamino group (Preferably C2-C20, More preferably Is C2-C16, Especially preferably, it is C2-C12, For example, methoxycarbonylamino etc., An aryloxycarbonylamino group (Preferably C7-20, More preferably, C7-16, Especially bar It is preferably 7 to 12 carbon atoms, for example, phenyloxycarbonylamino or the like, a sulfonylamino group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms). For example, methanesulfonylamino, benzenesulfonylamino, etc., sulfamoyl group (preferably C0-20, More preferably, it is C0-16, Especially preferably, it is C12-12, for example, Sulfamoyl, methyl sulfamoyl, dimethyl sulfamoyl, phenyl sulfamoyl, etc., carbamoyl groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms). For example, carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl and the like, alkylthio group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 carbon atom). It is -12, for example, methylthio , Ethylthio, etc.), an arylthio group (preferably 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, for example, phenylthio, etc.), a sulfonyl group (preferably Is C1-C20, More preferably, it is C1-C16, Especially preferably, it is C1-C12, For example, mesyl, tosyl, etc., A sulfinyl group (preferably C1-C20, More preferably, C1-C20) 1-16, Especially preferably, it is C1-C12, For example, methanesulfinyl, benzenesulfinyl, etc., A ureido group (Preferably C1-C20, More preferably, C1-C16, Especially preferably, Is C1-C12, for example, ureido, methylureido, phenylureido, etc., a phosphate amide group (preferably C1-C20, More preferably, C1-C16, Especially preferably, C1-C1) -12, for example, diethyl phosphate amide, Nylphosphate amide), hydroxy group, mercapto group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group , A hydrazino group, an imino group, a heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and as a hetero atom, for example, a nitrogen atom, an oxygen atom, a sulfur atom, and specifically, for example, Dazolyl, pyridyl, quinolyl, furyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, etc.), silyl group (preferably carbon number 3-40, more preferably carbon number) 3-30, Especially preferably, it is C3-C24, For example, trimethylsilyl, triphenylsilyl, etc. are mentioned. These substituents may further be substituted. In addition, when there are two or more substituents, they may be same or different. In addition, when possible, you may connect with each other and form a ring.

X ^1c and X ^2c represent a hydrogen atom or a substituent, and at least one represents a cyano group, a carbonyl group, a sulfonyl group, or an aromatic heterocycle. The substituent represented by X <^1c> and X <^2c> can apply the substituent T mentioned above. In addition, X ^1c and X ^2c to or representing substituent is may be further substituted by other substituent, X ^1c and X ^2c are to form a ring structure with each chukhwan.

X ^1c and X ^2c are preferably a hydrogen atom, an alkyl group, an aryl group, a cyano group, a nitro group, a carbonyl group, a sulfonyl group, an aromatic heterocyclic ring, more preferably a cyano group, a carbonyl group, a sulfonyl group, an aromatic heterocyclic ring, More preferably, it is a cyano group and a carbonyl group, Especially preferably, it is a cyano group and an alkoxycarbonyl group (-C (= O) OR (R is a C1-C20 alkyl group, a C6-C12 aryl group, and these combined). .

In general formula (5), it is preferably a compound represented by the following general formula (5-A).

General formula (5-A)

In the formula, R ^1c , R ^2c , R ^3c , R ^4c , R ^5c , R ^6c , R ^7c , R ^8c , R ^9c and R ^10c each independently represent a hydrogen atom or a substituent. X ^1c and X ^2c have the same meanings as those in General Formula (5), and preferred ranges are also the same.

R ^1c , R ^2c , R ^3c , R ^4c , R ^5c , R ^6c , R ^7c , R ^8c , R ^9c and R ^10c each independently represent a hydrogen atom or a substituent and the above-mentioned substituent T is applied as a substituent. can do. In addition, these substituents may be further substituted by another substituent, and substituents may be condensed and may form ring structure.

R ^1c , R ^2c , R ^3c , R ^4c , R ^5c , R ^6c , R ^7c , R ^8c , R ^9c and R ^10c , preferably hydrogen atom, alkyl group, alkenyl group, alkynyl group, aryl group, substituted or no Substituted amino group, alkoxy group, aryloxy group, hydroxy group, halogen atom, more preferably hydrogen atom, alkyl group, aryl group, alkyloxy group, aryloxy group, halogen atom, more preferably hydrogen atom, carbon 1 It is a -12 alkyl group, Especially preferably, it is a hydrogen atom and a methyl group, Most preferably, it is a hydrogen atom.

R ^3c and R ^8c are preferably hydrogen atom, alkyl group, alkenyl group, alkynyl group, aryl group, substituted or unsubstituted amino group, alkoxy group, aryloxy group, hydroxy group, halogen atom, more preferably hydrogen atom, carbon number It is a 1-20 alkyl group, a C0-C20 amino group, a C1-C12 alkoxy group, a C6-C12 aryloxy group, a hydroxy group, More preferably, it is a hydrogen atom, a C1-C12 alkyl group, C1-C12 It is an alkoxy group, Especially preferably, it is a hydrogen atom.

As general formula (5), It is a compound represented by following General formula (5-B) more preferably.

General formula (5-B)

^Wherein R ^3c and R ^8c Is the same meaning as those in General formula (5-A), and its preferable range is also the same. X ^3c represents a hydrogen atom or a substituent.

X <^3c> represents a hydrogen atom or a substituent, The substituent T mentioned above can be applied as a substituent, and if possible, you may further substitute by the other substituent. X ^3c is preferably a hydrogen atom, an alkyl group, an aryl group, a cyano group, a nitro group, a carbonyl group, a sulfonyl group, an aromatic heterocycle, more preferably a cyano group, a carbonyl group, a sulfonyl group, an aromatic heterocycle, and more preferably Is a cyano group and a carbonyl group, and particularly preferably a cyano group and an alkoxycarbonyl group (-C (= O) OR (R is a C1-20 alkyl group, a C6-12 aryl group, and a combination thereof).

As general formula (5), it is more preferably a compound represented by general formula (5-C).

General formula (5-C)

In formula, R <^3c> and R <^8c> are synonymous with those in General formula (5-A), and its preferable range is also the same. R ^21c represents an alkyl group having 1 to 20 carbon atoms.

R ^21c is preferably R ^3c and R ^8c In the case of divalent hydrogen, it is a C2-C12 alkyl group, More preferably, it is a C4-C12 alkyl group, More preferably, it is a C6-C12 alkyl group, Especially preferably, it is n-octyl group and tert- Octyl group, 2-ethylhexyl group, n-decyl group, n-dodecyl group, and most preferably 2-ethylhexyl group.

R ^21c is preferably R ^3c and R ^8c When it is other than hydrogen, the molecular weight of the compound represented by general formula (5-C) will be 300 or more, and a C20 or less carbon alkyl group is preferable.

The compound represented by General formula (5) can be synthesize | combined by the method as described in Journal of American Chemical Society 63, 3452 pages (1941).

Although the specific example of a compound represented by General formula (5) below is given, this invention is not limited to the following specific example at all.

`` Manufacture of cellulose acylate film ''

It is preferable to manufacture a cellulose acylate film by the solvent cast method. In the solvent cast method, a film is manufactured using the solution (dope) which melt | dissolved cellulose acylate in the organic solvent. The organic solvent preferably contains a solvent selected from ethers having 3 to 12 carbon atoms, ketones having 3 to 12 carbon atoms, esters having 3 to 12 carbon atoms, and halogenated hydrocarbons having 1 to 6 carbon atoms. . Ethers, ketones, and esters may have a cyclic structure. Compounds having two or more of functional groups of ethers, ketones and esters (ie, -O-, -CO- and COO-) can also be used as the organic solvent. The organic solvent may have other functional groups, such as an alcoholic hydroxyl group. In the case of the organic solvent which has two or more types of functional groups, the carbon atom number should just be in the defined range of the compound which has any one functional group.

Examples of ethers having 3 to 12 carbon atoms include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole and phentol This includes. Examples of ketones having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclohexanone and methylcyclohexanone. Examples of esters having 3 to 12 carbon atoms include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate and pentyl acetate. Examples of the organic solvent having two or more functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol and 2-butoxyethanol. The number of carbon atoms of the halogenated hydrocarbon is preferably 1 or 2, most preferably 1. It is preferable that halogen of halogenated hydrocarbon is chlorine. It is preferable that the ratio which the hydrogen atom of halogenated hydrocarbon is substituted by halogen is 25-75 mol%, It is more preferable that it is 30-70 mol%, It is further more preferable that it is 35-65 mol%, 40-60 mol Most preferred is%. Methylene chloride is a typical halogenated hydrocarbon. You may mix and use two or more types of organic solvents.

A cellulose acylate solution can be prepared by a general method. A general method means processing at a temperature (normal temperature or high temperature) of 0 degreeC or more. The solution can be prepared using a dope preparation method and apparatus in a conventional solvent cast method. In the general method, it is preferable to use halogenated hydrocarbons (particularly methylene chloride) as the organic solvent.

The amount of cellulose acylate is adjusted to contain 10-40 mass% in the solution obtained. The amount of cellulose acylate is more preferably 10 to 30% by mass. In the organic solvent (main solvent), you may add the arbitrary additive mentioned later. A solution can be prepared by stirring a cellulose acylate and an organic solvent at normal temperature (0-40 degreeC). The high concentration solution may be stirred under pressurized and heated conditions. Specifically, the cellulose acylate and the organic solvent are placed in a pressurized container and sealed, and the mixture is stirred while heating to a temperature not lower than the boiling point at room temperature of the solvent and not causing the solvent to boil under pressure. Heating temperature is 40 degreeC or more normally, Preferably it is 60-200 degreeC, More preferably, it is 80-110 degreeC.

Each component may be premixed beforehand and put into a container. Moreover, you may order to a container sequentially. The vessel needs to be configured to be able to stir. The vessel can be pressurized by injecting an inert gas such as nitrogen gas. Moreover, you may use the raise of the vapor pressure of a solvent by heating. Or after sealing a container, you may add each component under pressure. When heating, it is preferable to heat from the exterior of a container. For example, a jacket type heating device can be used. In addition, the entire container can be heated by forming a plate heater on the outside of the container, piping to circulate the liquid. It is preferable to form a stirring blade inside a container, and to stir using this. It is preferable that a stirring blade is length reaching the vicinity of the wall of a container. It is preferable to form a rake blade at the end of the stirring blade so that the liquid film on the wall of the container is fresh. Instruments may be provided with instruments such as pressure gauges and thermometers. Each component is dissolved in a solvent in a container. The prepared dope is taken out from the container after cooling, or after taking out, it is cooled using a heat exchanger or the like.

A solution can also be prepared by a cooling solution method. In the cooling dissolution method, the cellulose acylate can be dissolved in an organic solvent which is difficult to dissolve in the usual dissolution method. Moreover, even if it is a solvent which can melt | dissolve cellulose acylate by a conventional dissolution method, there exists an effect that a uniform solution can be obtained quickly by a cooling dissolution method. In the cooling solution method, initially, the cellulose acylate is slowly added while stirring in an organic solvent at room temperature. It is preferable to adjust the quantity of cellulose acylate so that it may contain 10-40 mass% in this mixture. The amount of cellulose acylate is more preferably 10 to 30% by mass. In addition, you may add arbitrary additives mentioned later in a mixture.

Next, the mixture is cooled to -100 to -10 占 폚 (preferably -80 to -10 占 폚, more preferably -50 to -20 占 폚, most preferably -50 to -30 占 폚). Cooling can be performed, for example in a dry ice methanol bath (-75 degreeC) or the cooled diethylene glycol solution (-30--20 degreeC). When it cools in this way, the mixture of a cellulose acylate and an organic solvent will solidify.

The cooling rate is preferably 4 ° C / minute or more, more preferably 8 ° C / minute or more, and most preferably 12 ° C / minute or more. The faster the cooling rate is, the more preferable it is, but 10000 ° C / sec is the theoretical upper limit, 1000 ° C / sec is the technical upper limit, and 100 ° C / sec is the practical upper limit. The cooling rate is a value obtained by dividing the difference between the temperature at the start of cooling and the final cooling temperature by the time from the start of cooling to the final cooling temperature.

Moreover, when this is heated to 0-200 degreeC (preferably 0-150 degreeC, more preferably 0-120 degreeC, most preferably 0-50 degreeC), a cellulose acylate will melt | dissolve in an organic solvent. The temperature increase may be left alone in room temperature or may be heated in a warm bath.

The heating rate is preferably 4 ° C / minute or more, more preferably 8 ° C / minute or more, and most preferably 12 ° C / minute or more. Although the heating rate is preferable as soon as possible, 10000 degree-C / sec is a theoretical upper limit, 1000 degree-C / sec is a technical upper limit, and 100 degree-C / sec is a practical upper limit. The heating rate is a value obtained by dividing the difference between the temperature at the start of heating and the final heating temperature by the time from the start of heating to the final heating temperature.

As described above, a uniform solution is obtained. Moreover, when melt | dissolution is inadequate, you may repeat operation of cooling and a heating. Whether dissolution is sufficient can be judged only by observing the external appearance of a solution by visual observation.

In the cooling dissolution method, it is preferable to use a sealed container in order to avoid water mixing due to condensation during cooling. In the cooling heating operation, the dissolution time can be shortened by pressurizing during cooling and depressurizing during heating. In order to perform pressurization and pressure reduction, it is preferable to use a pressure-resistant container.

In addition, a 20 mass% solution in which cellulose acylate (degree of acetylation: 60.9%, viscosity average degree of polymerization: 299) was dissolved in methyl acetate by a cooling dissolution method was found to have a sol state in the vicinity of 33 ° C. according to differential scanning calorimetry (DSC). The pseudo phase transition point of and gel exists, and it becomes a uniform gel state below this temperature. Therefore, this solution needs to be stored at a temperature above the pseudo phase transition temperature, preferably at a temperature of about 10 ° C plus the gel phase transition temperature. However, this pseudo phase transition temperature differs depending on the acetylation degree of cellulose acylate, viscosity average polymerization degree, solution concentration, and the organic solvent to be used.

From the prepared cellulose acylate solution (dope), a cellulose acylate film is manufactured by the solvent cast method.

The dope is flexible on a drum or band and evaporates the solvent to form a film. It is preferable to adjust the density | concentration of the dope before casting | flow_spread so that solid content may be 18 to 35%. The surface of the drum or the band is preferably finished in a mirror state. As for the casting and drying method in the solvent cast method, U.S. Pat.Nos. 2336310, 2367603, 2492078, 2492977, 2492978, 2607704, 2739069, 2739070, and British Patent 640731 Each specification of No. 736892, Unexamined-Japanese-Patent No. 45-4554, 49-5614, Unexamined-Japanese-Patent No. 60-176834, 60-203430, and 62-115035 are described. .

It is preferable that dope is cast on the drum or band whose surface temperature is 10 degrees C or less. It is preferable to let air dry for 2 second or more after being soft. The obtained film may be peeled off from the drum or the band, and further dried by hot air having a temperature change from 100 to 160 ° C in order to evaporate the residual solvent. The above method is described in JP-A-5-17844. According to this method, it is possible to shorten the time from casting to peeling. In order to carry out this method, it is necessary to gel dope at the surface temperature of the drum or band at the time of casting.

A plasticizer can be added to a cellulose acylate film in order to improve a mechanical property or to improve a drying speed. Phosphoric acid ester or carboxylic acid ester is used as a plasticizer. Examples of the phosphate ester include triphenyl phosphate (TPP) and tricresyl phosphate (TCP). Phthalic acid ester and citric acid ester are typical as carboxylic acid ester. Examples of phthalate esters include dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), dioctyl phthalate (DOP), diphenyl phthalate (DPP) and diethylhexyl phthalate (DEHP). . Examples of citric acid ester include O-acetyl citrate triethyl (OACTE) and O-acetyl citrate tributyl (OACTB). Examples of other carboxylic acid esters include butyl oleate, methylacetyl ricinoleate, dibutyl sebacate, and various trimellitic acid esters. Phthalate ester plasticizers (DMP, DEP, DBP, DOP, DPP, DEHP) are preferably used. DEP and DPP are particularly preferred.

It is preferable that the addition amount of a plasticizer is 0.1-25 mass% of the quantity of a cellulose ester, It is more preferable that it is 1-20 mass%, It is most preferable that it is 3-15 mass%.

A deterioration inhibitor (for example, antioxidant, peroxide decomposer, radical inhibitor, metal deactivator, acid scavenger, amine) may be added to a cellulose acylate film. The deterioration inhibitors are described in Japanese Unexamined Patent Publications No. 3-199201, 5-1907073, 5-194789, 5-271471, and 6-107854. It is preferable that the addition amount of a deterioration inhibitor is 0.01-1 mass% of the solution (dope) prepared from a viewpoint which the effect by addition of a deterioration inhibitor expresses, and suppresses the bleed out (exuding) of the deterioration inhibitor to the film surface. And it is more preferable that it is 0.01-0.2 mass%. Examples of particularly preferred deterioration inhibitors include butylated hydroxytoluene (BHT) and tribenzylamine (TBA).

<< stretching treatment of a cellulose acylate film >>

A cellulose acylate film can adjust retardation by an extending | stretching process. It is preferable that a draw ratio is 3 to 100%.

There is no restriction | limiting in particular about an extending method, A well-known method can be used. In terms of uniformity in plane, tenter stretching is particularly preferably used. It is preferable that the cellulose acylate film used for the 2nd aspect of this invention is at least 100 cm or more in width, It is preferable that the variation of Re value of the full width is +/- 5 nm, It is more preferable that it is +/- 3 nm. In addition, the deviation of the Rth value is preferably ± 10 nm, more preferably ± 5 nm. Moreover, it is preferable that the deviation of Re value and Rth value of a longitudinal direction also exists in the range of the deviation of the width direction.

In addition, an extending | stretching process may be performed in the middle of a film forming process, and the raw film which carried out film forming and winding up may be extended | stretched. In the former case, you may extend | stretch in the state containing the residual solvent amount, and it can extend | stretch preferably 2-30%. At this time, it is preferable to extend | stretch in the direction orthogonal to a longitudinal direction, conveying a film in a longitudinal direction, and to make the slow axis of the film orthogonal to the elongate direction of the film.

The stretching temperature can be selected according to the residual solvent amount and the film thickness at the time of stretching. When extending | stretching in the state containing a residual solvent, it is preferable to dry after extending | stretching. A drying method can be performed according to the method as described in the film forming of the said film.

The thickness of the cellulose acylate film after stretching is 110 microns or less, preferably 40 to 110 microns, more preferably 60 to 110 microns, and preferably 80 to 110 microns.

≪Surface treatment of cellulose acylate film≫

When using the transparent film which consists of a cellulose acylate film as a transparent protective film of a polarizing plate, it is preferable to surface-treat a cellulose acylate film. As the surface treatment, corona discharge treatment, glow discharge treatment, flame treatment, acid treatment, alkali treatment or ultraviolet irradiation treatment are performed. Particular preference is given to acid treatment or alkali treatment, i.e. saponification treatment to cellulose acylate.

Cellulose acylate, including a rod-like compound having a linear structure having at least two aromatic rings as described above, satisfying a desired retardation value Re, Rth and Re / Rth ratio, and having a film thickness of 40 microns to 110 microns The film satisfies the optical properties as the transparent film and can be used in various liquid crystal display devices as one member of the optical compensation film.

[Optical anisotropic layer]

The optical compensation film which concerns on the 2nd aspect of this invention has at least one optically anisotropic layer formed from the liquid crystalline compound. The optically anisotropic layer may be directly formed on the surface of the transparent film, or an alignment film may be formed on the transparent film, and may be formed on the alignment film. Moreover, it is also possible to produce the optical compensation film which concerns on the 2nd aspect of this invention by transferring the liquid crystalline compound layer formed from the other base material on a transparent film using an adhesive, an adhesive agent, etc.

As a liquid crystalline compound used for formation of an optically anisotropic layer, a rod-like liquid crystalline compound and a disk-shaped liquid crystalline compound (Hereinafter, a disk-shaped liquid crystalline compound may be called a "discotic liquid crystalline compound"). The rod-like liquid crystal compound and the discotic liquid crystal compound may be a polymer liquid crystal or a low molecular liquid crystal. In addition, the compound finally contained in an optically anisotropic layer does not need to show liquid crystal anymore, for example, when a low molecular liquid crystalline compound is used for preparation of an optically anisotropic layer, in the process of forming an optically anisotropic layer, The aspect which the compound crosslinked and did not show liquid crystal may be sufficient.

(Bar-shaped liquid crystalline compound)

As a rod-shaped liquid crystalline compound which can be used for the 2nd aspect of this invention, azomethine, azoxy, cyano biphenyl, cyano phenyl ester, benzoic acid ester, cyclohexane carboxylic acid phenyl ester, and cyano phenyl Cyclohexanes, cyano substituted phenyl pyrimidines, alkoxy substituted phenyl pyrimidines, phenyldioxanes, tolans and alkenylcyclohexylbenzonitriles are preferably used. Moreover, a metal complex is also contained in a rod-shaped liquid crystalline compound. Moreover, the liquid crystal polymer which contains a rod-shaped liquid crystalline compound in a repeating unit can also be used. In other words, the rod-like liquid crystalline compound may be bonded to the (liquid crystal) polymer.

The rod-shaped liquid crystalline compounds are described in Chapter 4, Chapter 7 and Chapter 11 of the Japanese Chemical Society (1994) Japanese Chemical Society, and Chapter 3 of the 142 Committee Edition of the Liquid Crystal Devices Handbook. There is.

It is preferable that the birefringence of the rod-like liquid crystalline compound used for the second aspect of the present invention is in the range of 0.001 to 0.7.

It is preferable that a rod-shaped liquid crystalline compound has a polymeric group in order to fix the orientation state. The polymerizable group is preferably an unsaturated polymerizable group or an epoxy group, more preferably an unsaturated polymerizable group, and most preferably an ethylenically unsaturated polymerizable group.

(Discotic liquid crystalline compound)

As a discotic liquid crystalline compound, C. Destrade et al. Report, Mo1. Cryst. Vol. 71, p. 111 (1981), Benzene derivatives, C. Destrade et al., Mo1. Cryst. Trexenes derivatives described in Volume 122, page 141 (1985), Physics lett, A, Vol. 78, page 82 (1990), B. Kohne et al., Angew. Chem. The cyclohexane derivatives described in Volume 96, page 70 (1984) and J. M. Lehn et al., J. Chem. Commun., Page 1794 (1985), by J. Zhang et al., J. Am. Chem. Soc. Azacrown-based or phenylacetylene-based macrocycles described in volume 116, page 2655 (1994).

The said discotic liquid crystalline compound also contains the compound which shows liquid crystallinity of the structure which the linear alkyl group, the alkoxy group, or the substituted benzoyloxy group substituted on the radiation as a side chain of a mother nucleus with respect to the mother nucleus of a molecular center. It is preferable that a molecule | numerator or an aggregate of molecules is a compound which has rotational symmetry and can give a fixed orientation.

As mentioned above, when the optically anisotropic layer is formed from the liquid crystal compound, the compound finally contained in the optically anisotropic layer does not need to exhibit liquid crystal any more. For example, when a low molecular discotic liquid crystalline compound has a group reacting with heat or light, the group reacts with heat or light, polymerizes or crosslinks, and forms an optically anisotropic layer by high molecular weight. The compound contained in the optically anisotropic layer may have already lost liquid crystallinity. Preferable examples of the discotic liquid crystalline compound are described in JP-A-8-50206. Moreover, about the superposition | polymerization of a discotic liquid crystalline compound, it describes in Unexamined-Japanese-Patent No. 8-27284.

In order to fix a discotic liquid crystalline compound by superposition | polymerization, it is necessary to couple a polymeric group as a substituent to the disk-shaped core of a discotic liquid crystalline compound. However, when a polymeric group is directly connected to a disk core, it becomes difficult to maintain an orientation state in a polymerization reaction. Thus, a linking group is introduced between the disk core and the polymerizable group. Therefore, it is preferable that the discotic liquid crystalline compound which has a polymeric group is a compound represented by following formula (III).

Formula (III)

D (-LQ) _n

In formula, D is a disc shaped core, L is a bivalent coupling group, Q is a polymeric group, n is an integer of 4-12.

An example of disk shaped core (D) is shown below. In each of the following examples, LQ (or QL) means a combination of a divalent linking group (L) and a polymerizable group (Q).

In Formula (III), a bivalent coupling group (L) is 2 selected from the group which consists of an alkylene group, an alkenylene group, an arylene group, -CO-, -NH-, -O-, -S-, and its combination. It is preferable that it is a valent coupling group. The divalent linking group (L) is more preferably a divalent linking group obtained by combining at least two divalent groups selected from the group consisting of an alkylene group, an arylene group, -CO-, -NH-, -O- and S-. . The divalent linking group (L) is most preferably a divalent linking group in which at least two divalent groups selected from the group consisting of an alkylene group, an arylene group, -CO- and O- are combined. It is preferable that carbon number of the said alkylene group is 1-12. It is preferable that the carbon atom number of the said alkenylene group is 2-12. It is preferable that carbon number of the said arylene group is 6-10.

Examples of the divalent linking group L are shown below. The left side couple | bonds with a disk shaped core (D), and the right side couple | bonds with a polymeric group (Q). AL means an alkylene group or an alkenylene group, AR means an arylene group. In addition, the alkylene group, alkenylene group, and arylene group may have a substituent (for example, an alkyl group).

L1: -AL-CO-O-AL-

L2: -AL-CO-O-AL-O-

L3: -AL-CO-O-AL-O-AL-

L4: -AL-CO-O-AL-O-CO-

L5: -CO-AR-O-AL-

L6: -CO-AR-O-AL-O-

L7: -CO-AR-O-AL-O-CO-

L8: -CO-NH-AL-

L9: -NH-AL-O-

L10: -NH-AL-O-CO-

L11: -O-AL-

L12: -O-AL-O-

L13: -O-AL-O-CO-

L14: -O-AL-O-CO-NH-AL-

L15: -O-AL-S-AL-

L16: -O-CO-AR-O-AL-CO-

L17: -O-CO-AR-O-AL-O-CO-

L18: -O-CO-AR-O-AL-O-AL-O-CO-

L19: -O-CO-AR-O-AL-O-AL-O-AL-O-CO-

L20: -S-AL-

L21: -S-AL-O-

L22: -S-AL-O-CO-

L23: -S-AL-S-AL-

L24: -S-AR-AL-

The polymerizable group (Q) of Formula (III) is determined according to the kind of polymerization reaction. The polymerizable group (Q) is preferably an unsaturated polymerizable group or an epoxy group, more preferably an unsaturated polymerizable group, and most preferably an ethylenically unsaturated polymerizable group.

In Formula (III), n is an integer of 4-12. The specific number is determined according to the kind of disk-shaped core D. Moreover, although the combination of several L and Q may differ, the same thing is preferable.

In the 2nd aspect of this invention, the molecule | numerator of the said rod-shaped compound or the said discotic compound is fixed in the orientation state among the said optically anisotropic layers. The orientation average direction of the molecular symmetry axis of the liquid crystalline compound at the interface on the transparent film side is about 0 degrees or about 90 degrees with the slow axis in the plane of the transparent film. In addition, in this specification, "about 0 degree or 90 degree" means the angle of the range of 0 degrees ± 5 degrees or 90 degrees ± 5 degrees, Preferably it is 42-48 degrees, More preferably, 43 It is -47 degrees. It is preferable that the average direction of the molecular symmetry axis of the liquid crystalline compound in the optically anisotropic layer is 43 ° to 47 ° with respect to the longitudinal direction of the transparent film (that is, the fast axis direction of the transparent film).

The orientation average direction of the molecular symmetry axis of the liquid crystal compound can generally be adjusted by selecting the material of the liquid crystal compound or the alignment film, or by selecting the rubbing treatment method. In the second aspect of the present invention, for example, when the alignment film for forming the optically anisotropic layer is produced by a rubbing treatment, the rubbing treatment is performed in a direction of 45 ° with respect to the slow axis of the transparent film. The at least the orientation average direction in the transparent film interface can form the optically anisotropic layer whose 45 degree with respect to the slow axis of a transparent film. For example, the optical compensation film according to the second aspect of the present invention can be produced continuously by using a long transparent film having a slow axis parallel to the longitudinal direction. Specifically, the coating liquid for forming an alignment film is continuously applied to the surface of the long transparent film to prepare a film, and then the surface of the film is continuously rubbed in a direction of 45 ° in the longitudinal direction to produce an alignment film. The coating liquid for optically anisotropic layer formation containing a liquid crystalline compound is continuously apply | coated on the produced oriented film, the molecule | numerator of a liquid crystalline compound is oriented, and an optically anisotropic layer is produced by fixing in that state, and a long optical compensation The film can be produced continuously. The optical compensation film produced in a long shape is cut into a desired shape before being put into a liquid crystal display device.

In addition, with respect to the orientation mean direction of the molecular symmetry axis on the surface side (air side) of the liquid crystalline compound, the orientation mean direction of the molecular symmetry axis of the liquid crystalline compound on the air interface side is about 0 ° or 90 with respect to the slow axis of the transparent film. It is preferable that it is °, it is more preferable that it is 42-48 degrees, and it is still more preferable that it is 43-47 degrees. The orientation average direction of the molecular symmetry axis of the liquid crystalline compound on the air interface side can generally be adjusted by selecting the kind of additive used with a liquid crystalline compound or a liquid crystalline compound. As an example of the additive used with a liquid crystalline compound, a plasticizer, surfactant, a polymerizable monomer, a polymer, etc. are mentioned. The degree of change in the orientation direction of the molecular symmetry axis can also be adjusted by selection of the liquid crystal compound and the additive as described above. In particular, the surfactant is preferably compatible with the surface tension control of the coating liquid described above.

It is preferable that the plasticizer, surfactant, and polymerizable monomer used with a liquid crystalline compound have compatibility with a discotic liquid crystalline compound, and do not receive the change of the inclination angle of a liquid crystalline compound, or do not inhibit orientation. Polymerizable monomers (for example, compounds having a vinyl group, vinyloxy group, acryloyl group and methacryloyl group) are preferable. It is preferable that the addition amount of the said compound exists in the range of 1-50 mass% generally with respect to a liquid crystalline compound, and exists in the range of 5-30 mass%. Moreover, adhesiveness between an orientation film and an optically anisotropic layer can be improved when mixing and using the monomer whose polymerizable reactive functional group number is four or more.

When using a discotic liquid crystalline compound as a liquid crystalline compound, it is preferable to use the polymer which has some compatibility with a discotic liquid crystalline compound, and receives a change of inclination angle for a discotic liquid crystalline compound.

Examples of the polymer include cellulose esters. Preferred examples of the cellulose esters include cellulose acetate, cellulose acetate propionate, hydroxypropyl cellulose and cellulose acetate butyrate. In order not to inhibit the orientation of the discotic liquid crystalline compound, the amount of the polymer added is preferably in the range of 0.1 to 10% by mass, more preferably in the range of 0.1 to 8% by mass with respect to the discotic liquid crystalline compound. It is more preferable to exist in the range of 0.1-5 mass%.

70-300 degreeC is preferable and, as for the discotic nematic liquid crystal phase-solid-state transition temperature of a discotic liquid crystalline compound, 70-170 degreeC is more preferable.

In the second aspect of the present invention, the optically anisotropic layer preferably has at least in-plane optical anisotropy. The optical characteristic of an optically anisotropic layer is determined according to the optical characteristic and mode of the liquid crystal cell used as the object of optical compensation. When using for a liquid crystal display device of TN mode, it is preferable that in-plane retardation Re of the said optically anisotropic layer is 3-300 nm, It is more preferable that it is 5-200 nm, It is further more preferable that it is 10-100 nm. . It is preferable that it is 20-400 nm, and, as for retardation Rth of the thickness direction of the said optically anisotropic layer, it is more preferable that it is 50-200 nm. In addition, the thickness of the optically anisotropic layer is preferably 0.1 to 20 microns, more preferably 0.5 to 15 microns, and most preferably 1 to 10 microns.

[Alignment Film]

The optical compensation film which concerns on the 2nd aspect of this invention may have an oriented film between a transparent film and an optically anisotropic layer. Moreover, after producing an optically anisotropic layer on an alignment film only when an optically anisotropic layer is produced, only this optically anisotropic layer may be transferred on a transparent film.

In the second aspect of the invention, the alignment film is preferably a layer made of a crosslinked polymer. Although the polymer used for an oriented film is a polymer which can itself crosslink, any of the polymers bridge | crosslinked by a crosslinking agent can be used. The alignment film is formed by reacting a polymer with a functional group or a polymer having a functional group and reacting between the polymers by light, heat or PH change, or by using a crosslinking agent which is a compound having high reaction activity. It can form by introduce | transducing a coupling group derived and crosslinking between polymers.

Orientation film which consists of a crosslinked polymer can be normally formed by apply | coating the coating liquid containing the said polymer or the mixture of a polymer and a crosslinking agent on a support body, and then heating.

In the rubbing process described later, in order to suppress oscillation of the alignment film, it is preferable to increase the degree of crosslinking. Regarding the amount (Mb) of the crosslinking agent added to the coating liquid, the value (1- (Ma / Mb)) obtained by subtracting the ratio (Ma / Mb) of the amount (Ma) of the crosslinking agent remaining after crosslinking from 1 (crosslinking degree) When defined, the crosslinking degree is preferably 50% to 100%, more preferably 65% to 100%, and most preferably 75% to 100%.

In the 2nd aspect of this invention, the polymer used for the said oriented film can use either the polymer which can be crosslinked itself, or the polymer crosslinked by a crosslinking agent. Of course, a polymer having both functions can also be used. Examples of the polymer include polymethyl methacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleinimide copolymer, polyvinyl alcohol and modified polyvinyl alcohol, poly (N-methylol acrylamide), styrene / Vinyltoluene copolymer, chlorosulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, carboxymethylcellulose, gelatin, polyethylene, poly And polymers such as propylene and polycarbonate, and compounds such as silane coupling agents. Examples of preferred polymers are water-soluble polymers such as poly (N-methylolacrylamide), carboxymethylcellulose, gelatin, polyvinyl alcohol and modified polyvinyl alcohol, and gelatin, polyvinyl alcohol and modified polyvinyl alcohol are preferred. In particular, polyvinyl alcohol and modified polyvinyl alcohol can be mentioned.

Among the polymers, polyvinyl alcohol or modified polyvinyl alcohol is preferable.

As polyvinyl alcohol, the saponification degree has 70-100% thing, for example, saponification degree 80-100% is preferable, and saponification degree 82-98% is more preferable, for example. The polymerization degree is preferably in the range of 100 to 3000.

Examples of the modified polyvinyl alcohol include those modified by copolymerization (as a modifying group, for example, COONa, Si (OX) ₃ , N (CH ₃ ) ₃ Cl, C ₉ H ₁₉ COO, SO ₃ Na, C ₁₂ H _25, etc.). Is introduced), modified by chain transfer (as a modifying group, for example, COONa, SH, SC ₁₂ H ₂₅ And modified polyvinyl alcohols such as those modified by block polymerization (COOH, CONH ₂ , COOR, C ₆ H _5, etc. are introduced as the modifying group). . As polymerization degree, the range of 100-3000 is preferable. Among them, unmodified or modified polyvinyl alcohol having a saponification degree of 80 to 100% is preferable, and more preferably unmodified to alkylthio modified polyvinyl alcohol having a saponification degree of 85 to 95%.

As the modified polyvinyl alcohol used for the alignment film, a reactant of a compound represented by the following general formula (6) with polyvinyl alcohol is preferable.

General formula (6):

^Wherein R ^1d represents an unsubstituted alkyl group or an alkyl group substituted with an acryloyl group, methacryloyl group or an epoxy group, W represents a halogen atom, an alkyl group or an alkoxy group, and X ^ld represents an active ester, an acid anhydride or an acid The atom group required in order to form a halide is shown, 1 represents 0 or 1, n represents the integer of 0-4.

Moreover, as modified polyvinyl alcohol used for an oriented film, the reaction material of the compound represented by following General formula (7) and polyvinyl alcohol is also preferable.

General formula (7):

In the formula, X ^2d represents an atomic group necessary for forming an active ester, an acid anhydride or an acid halide, and m represents an integer of 2 to 24.

Examples of the polyvinyl alcohol used to react with the compounds represented by the general formulas (6) and (7) include the above-denatured polyvinyl alcohol and the copolymer-modified one, that is, modified by chain transfer. And modified products of polyvinyl alcohol, such as those modified or modified by block polymerization. Preferable examples of the specific modified polyvinyl alcohol are described in detail in Japanese Patent Application Laid-open No. Hei 8-338913.

When using hydrophilic polymers, such as polyvinyl alcohol, for an oriented film, it is preferable to control a water content from a viewpoint of a film degree, It is preferable that it is 0.4%-2.5%, It is more preferable that it is 0.6%-1.6%. The water content can be measured with a commercially available Karl Fischer moisture content meter.

In addition, the alignment film is preferably a film thickness of 10 microns or less.

[Polarizing Plate]

As a 2nd aspect of this invention, the polarizing plate which consists of a polarizing film and a pair of protective film which clamps the polarizing film can be used. For example, the polarizing plate obtained by dyeing the polarizing film which consists of polyvinyl alcohol films, etc. with iodine, extending | stretching, and laminating | stacking both surfaces with a protective film can be used. The polarizing plate is disposed outside the liquid crystal cell. It is preferable to arrange | position a pair of polarizing plates which consist of a polarizing film and a pair of protective film which clamps the polarizing film, sandwiching a liquid crystal cell. Moreover, as above-mentioned, the protective film arrange | positioned at the liquid crystal cell side may be the optical compensation film (transparent film) which concerns on the 2nd aspect of this invention.

(Shield)

The polarizing plate which can be used by the 2nd aspect of this invention may laminate | stack a pair of protective film (also called protective film) on both surfaces of a polarizing film. The kind of protective film is not specifically limited, Cellulose esters, such as a cellulose acetate, a cellulose acetate butyrate, cellulose ester, a polycarbonate, a polyolefin, polystyrene, polyester, etc. can be used. As mentioned above, the cellulose acylate film which satisfy | fills the optical characteristic as the said transparent film can also be used as a protective film.

It is preferable that a protective film is supplied in roll form normally, and is bonded continuously so that a longitudinal direction may correspond with respect to a long polarizing film. Here, the orientation axis (ground axis) of the protective film may be in any direction, and in view of operational simplicity, the orientation axis of the protective film is preferably parallel to the longitudinal direction.

In the case of imparting optical compensation capability to the protective film, Re / Rth (450 nm), which is the ratio of Re and Rth in the wavelength of 450 nm in the visible light region, is 0.39-0.95 times that of Re / Rth (550 nm) in the wavelength of 550 nm. Further, Re / Rth (650 nm) at a wavelength of 650 nm is 1.04 to 2.20 times that of Re / Rth (550 nm) at a wavelength of 550 nm, and retardation in the thickness direction at a wavelength of 550 nm of the visible light region of the transparent film is performed. It is preferable that Rth is 70 nm-400 nm.

On the other hand, in the aspect which does not function a protective film as a transparent film, it is preferable that the retardation of a transparent protective film is low, and especially the aspect which the transmission axis of a polarizing film and the orientation axis of a transparent protective film are not parallel, especially the retardation value of a transparent protective film. If it is more than this fixed value, since the polarization axis and the orientation axis (ground axis) of a transparent protective film are shifted at an angle, linearly polarized light changes to elliptical polarization, and it is not preferable. As the low retardation polymer film, polyolefins such as cellulose triacetate, zeonex, zeonoa (all manufactured by Nippon Xeon Co., Ltd.), and ARTON (manufactured by JSR Co., Ltd.) are preferably used. In addition, the non-birefringent optical resin material as described in Unexamined-Japanese-Patent No. 8-110402 or 11-293116 is mentioned, for example. In this aspect, when using the laminated body which consists of a support body and the optically anisotropic layer which consists of a liquid crystalline compound on a support body as an optical compensation layer, a protective film may serve as the support body of an optically anisotropic layer.

When bonding a protective film and a polarizing film, so that the slow axis (orientation axis) of at least one protective film (protective film arrange | positioned near a liquid crystal cell when entering a liquid crystal display device) and the absorption axis (extension axis) of the said polarizing film may cross | intersect, It is preferable to laminate a protective film and a polarizing film. Specifically, the angle between the absorption axis of the polarizing film and the slow axis of the protective film is preferably 10 ° to 90 °, more preferably 20 ° to 70 °, still more preferably 40 ° to 50 °, particularly preferably. Preferably it is 43-47 degrees. The angle between the slow axis of the other protective film and the absorption axis of the polarizing film is not particularly limited and can be appropriately set according to the purpose of the polarizing plate, but it is preferable that it is in the above range, and that the slow axes of the pair of protective films coincide with each other. desirable.

Moreover, when the slow axis of a protective film and the absorption axis of a polarizing film are mutually parallel, the mechanical stability of the polarizing plate of the dimension change of a polarizing plate and prevention of curl can be improved. The same effect can be obtained when at least two axes of a total of three films of a polarizing film and a pair of protective films, a slow axis of one protective film and a polarizing film absorption axis, or a slow axis of two protective films are substantially parallel.

≪Adhesive≫

Although the adhesive agent of a polarizing film and a protective film is not specifically limited, PVA system resin (it contains modified PVA, such as an acetacetyl group, a sulfonic acid group, a carboxyl group, an oxyl alkylene group), the boron compound aqueous solution, etc. are mentioned, Especially, PVA System resin is preferable. As for the thickness of an adhesive bond layer, after drying, 0.01-10 microns are preferable, and 0.05-5 microns are especially preferable.

≪Integrated Manufacturing Process of Polarizing Film and Transparent Protective Film≫

Although the polarizing plate which can be used by a 2nd aspect of this invention has a drying process which shrinks | stretches and reduces a volatile fraction after extending | stretching the film for polarizing films, a post-heating process after bonding a transparent protective film to at least one surface after drying or during drying It is preferable to have. As an aspect in which the said transparent protective film overlaps the support body of the optically anisotropic layer which functions as a transparent film, it is preferable to post-heat after attaching the transparent protective film which has a transparent protective film on one side and an optically anisotropic layer on the opposite side. As a specific method of adhesion, during the drying process of the film, the transparent protective film is bonded to the polarizing film using an adhesive in a state where both ends are kept, and then cut or cut at both ends, or after drying, the film for polarizing film is released from both end holding parts. And after inserting a sheath in both ends of a film, there exists a method, such as bonding a transparent protective film. As a method of inserting a sheath, general techniques, such as a method of cutting with a cutter such as a knife and a method of using a laser, can be used. After application, it is preferable to heat the adhesive to dry it and to improve the polarization performance. As heating conditions, although it changes with an adhesive agent, 30 degreeC or more is preferable in a water system, More preferably, it is 40 degreeC-100 degreeC, More preferably, it is 50 degreeC-90 degreeC. It is more desirable for these processes to be manufactured in a consistent line in terms of performance and production efficiency.

≪Performance of Polarizing Plate≫

The optical properties and durability (short-term, long-term storage property) of a polarizing plate made of a transparent protective film, a polarizer, and a transparent support for use in the second aspect of the present invention are commercially available super high contrast products (e.g., manufactured by Sanritsu Co., Ltd.). HLC 2-5618, etc.) It is preferable to have a performance equal or more. Specifically, visible light transmittance is 42.5% or more, and polarization degree {(Tp-Tc) / (Tp + Tc)} 1/2 ≥ 0.9995 (where Tp is parallel transmittance and Tc is orthogonal transmittance). The change rate of light transmittance before and after 500 hours in a% RH atmosphere at 500 ° C. and 500 hours in a dry atmosphere is 3% or less depending on the absolute value, 1% or less, and the change rate of polarization degree is 1% according to the absolute value. In addition, it is preferable that it is 0.1% or less further.

An Example is given to the following and this invention is demonstrated to it further more concretely. The materials, reagents, ratios, operations, and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the Example shown below.

Example 1-1

<Production of Cellulose Acetate Film>

The following composition was thrown into the mixing tank, it stirred while heating, each component was melt | dissolved, and the cellulose acetate solution was prepared.

Cellulose Acetate Solution Composition

100 parts by mass of cellulose acetate having a degree of acetylation of 60.7 to 69.1%

Triphenyl phosphate (plasticizer) 7.8 parts by mass

3.9 parts by mass of biphenyldiphenyl phosphate (plasticizer)

Methylene chloride (first solvent) 336 parts by mass

29 parts by mass of methanol (second solvent)

11 parts by mass of 1-butanol (third solvent)

16 mass parts of following retardation increasing agents, 92 mass parts of methylene chlorides, and 8 mass parts of methanol were thrown into another mixing tank, and it stirred, heating, and prepared the retardation increasing agent solution. 25 mass parts of retardation increasing agent solutions were mixed with 474 mass parts of cellulose acetate solutions, and it fully stirred, and dope was prepared. The addition amount of the retardation increasing agent was 6.0 mass parts with respect to 100 mass parts of cellulose acetate.

Retardation synergist

The obtained dope was cast using a band stretching machine. After the film surface temperature on a band became 40 degreeC, it dried for 1 minute by 70 degreeC warm air from a band, and dried a film by 140 degreeC dry air for 10 minutes from a band, and the residual amount of cellulose acetate films (thickness) : 80 µm) was produced. Re-retardation value and Rth retardation value in wavelength 633nm using the automatic birefringence meter (KOBRA 21 ADH, the Ojiometer Co., Ltd. product) about the produced cellulose acetate film (transparent support body, transparent protective film). Was measured. Re was 8 nm and Rth was 78 nm. The produced cellulose acetate film was immersed in 2.0 N potassium hydroxide solution (25 ° C) for 2 minutes, neutralized with sulfuric acid, washed with pure water, and then dried. In this way, the cellulose acetate film for transparent protective films was produced.

<Formation of alignment film>

On this cellulose acetate film, the application liquid of the following composition was apply | coated 28 ml / m <2> with the wire bar coater of # 16. It dried for 60 second by the warm air of 60 degreeC, and 150 second by the warm air of 90 degreeC. Next, the formed film was subjected to a rubbing treatment so as to be oriented in a direction parallel to the in-plane slow axis (parallel direction and parallel direction) of the cellulose acetate film (that is, the rubbing axis was parallel to the slow axis of the cellulose acetate film).

Alignment film coating liquid composition

20 parts by mass of the following modified polyvinyl alcohol

360 parts by mass of water

120 parts by mass of methanol

Glutalaldehyde (crosslinking agent) 1.0 parts by mass

Modified polyvinyl alcohol

<Formation of Optically Anisotropic Layer>

91.0 g of the following disk-like (liquid crystalline) compounds, ethylene oxide-modified trimethylolpropane triacrylate (V # 360, Osaka Organic Chemical Co., Ltd.) 9.0 g, cellulose acetate butyrate (CAB 551-) on an alignment film 0.2, Eastman Chemical Co., Ltd. 2.0g, cellulose acetate butyrate (CAB 531-1, Eastman Chemical Co., Ltd.) 0.5g, photoinitiator (Irgacure 907, Chiba-Gaiyi Co., Ltd.) 3.0g, sensitizer (Kayakyua 1.03.6 of 1.0 g of DETX, Nippon Kayaku Co., Ltd., and 1.3 g of a fluoroaliphatic group-containing copolymer (manufactured by Megapak F 780 Dainippon Ink, Co., Ltd.) with 207 g of methyl ethyl ketone were # 3.6. 6.2 ml / m <2> was apply | coated in the wire bar. This was heated for 2 minutes in the constant temperature zone of 130 degreeC, and the disk shaped compound was orientated. Next, UV irradiation was performed for 1 minute using a 120 W / cm high-pressure mercury lamp under an atmosphere of 60 ° C. to polymerize the disk compound. Thereafter, the mixture was allowed to cool to room temperature. In this way, an optically anisotropic layer was formed and the optical compensation sheet was produced.

Liquid crystalline disk compound (A)

In the produced optically anisotropic layer, the disk-shaped liquid crystalline compound has an angle (tilt angle) between the disk surface and the transparent protective film increasing from the transparent protective film toward the air interface, and is hybridly oriented at an average inclination angle of 37 °. The optically anisotropic layer was a uniform film without defects such as sullene. The thickness of the formed optically anisotropic layer was 1.7 micrometers. The inclination angle was calculated by an automatic birefringence meter (MKOBRA 21 ADH, manufactured by Oji Measuring Instruments Co., Ltd.).

When the nonuniformity of the optical compensation sheet obtained by making a polarizing plate into a cross nicol arrangement was observed, even if it looked from the front and the direction inclined to 60 degrees from normal, the nonuniformity was not able to be detected.

(Production of polarizer)

PVA having an average degree of polymerization of 4000 and a degree of saponification of 99.8 mol% was dissolved in water to obtain an aqueous solution of 4.0%. The solution was band-flexed and dried using a tapered die, and the film was formed so that the width before stretching was 110 mm, the thickness was 120 m at the left end, and 135 m at the right end.

The film was peeled off from the band, tilted and stretched in a 45 degree direction in a dry state, soaked at 30 ° C. for 1 minute in an aqueous solution of 0.5 g / l of iodine and 50 g / l of potassium iodide as it was, followed by 100 g / l of boric acid and 60 g of potassium iodide. It was immersed for 5 minutes at 70 degreeC in 1 liter of aqueous solution, and also it washed with water at 20 degree | times for 10 second in the water washing tank, dried at 80 degreeC for 5 minutes, and obtained the iodine type polarizer. The polarizer was 20 micrometers in width | variety 1340 mm and both left and right.

Iodine was adsorbed to the stretched polyvinyl alcohol film to produce a polarizing film, and the prepared optical compensation sheet was bonded to one side of the polarizing film by the support surface using a polyvinyl alcohol-based adhesive. In addition, saponification was performed to a cellulose triacetate film (TD-80U, manufactured by Fujishashin Film Co., Ltd.) having a thickness of 80 µm, and bonded to the opposite side of the polarizing film using a polyvinyl alcohol-based adhesive. It was arrange | positioned so that it might become perpendicular | vertical to the absorption axis of a polarizing film and the slow axis (parallel direction and parallel direction) of the support body of an optical compensation sheet. In this way, a polarizing plate was produced.

In the produced TN cell, the produced polarizing plate was bonded one by one to the observer side and the backlight side via an adhesive so that an optical compensation sheet might become a liquid crystal cell side. At this time, the liquid crystal display device was produced by adjusting the absorption axis direction of the polarizing plate and the orientation control direction of the optical compensation sheet to be parallel to the rubbing direction of the liquid crystal cell facing each other.

Example 1-2

(Production of support)

The following composition was thrown into the mixing tank, it stirred while heating, each component was melt | dissolved, and the cellulose acetate solution was prepared.

Cellulose Acetate Solution Composition Acetylation degree 60.9% of cellulose acetate 100 parts by weight triphenylphosphate (plasticizer) 7.8 parts by weight biphenyldiphenylphosphate (plasticizer) 3.9 parts by weight methylene chloride (first solvent) 300 parts by weight methanol (second solvent) 45 parts by weight dye 0.009 parts by weight (360 FP manufactured by Sumika Fine Chem Co., Ltd.)

16 mass parts of following retardation increasing agents, 80 mass parts of methylene chlorides, and 20 mass parts of methanol were thrown into another mixing tank, and it stirred, heating, and prepared the retardation increasing agent solution.

36 parts by mass of the retardation synergist solution and 1.1 parts by mass of silica fine particles (R 972, manufactured by Aerosil) were mixed with 464 parts by mass of the cellulose acetate solution, and dope was sufficiently prepared. The addition amount of the retardation increasing agent was 5.0 mass parts with respect to 100 mass parts of cellulose acetate. In addition, the addition amount of a silica fine particle was 0.15 mass part with respect to 100 mass parts of cellulose acetate.

The obtained dope was cast | flow_spreaded using the flexible machine which has a band of 2 m in width and 65 m in length. After the film surface temperature on a band became 40 degreeC, it dried for 1 minute and peeled off, and it extended | stretched 28% in the width direction using the tenter by the drying air of 140 degreeC. Then, it dried for 20 minutes by the drying air of 135 degreeC, and produced the transparent support body whose residual solvent amount is 0.3 mass%.

The width of the transparent support was 1340 mm and the thickness was 46 μm.

The transparent support was reconditioned at a wavelength of 590 nm using an automatic birefringence meter (KOBRA 21 ADH, Oji Scientific Instruments Co., Ltd.) for 2 hours at a temperature of 20 ° C. and a relative humidity of 20%. It was 19.0 nm when the value Re was measured. Moreover, it was 88 nm when the retardation value (Rth) in wavelength 590 nm was measured.

Next, it was 18.9 nm when the transparent support body was temperature-regulated and humidified for 2 hours on condition of the temperature of 10 degreeC, and the relative humidity 20%, and similarly the retardation value Re in wavelength 633nm was measured. Moreover, it was 87.6 nm when the retardation value (Rth) in wavelength 633 nm was measured.

10 mL / m <2> of 1.0N potassium hydroxide solution (solvent: water / isopropyl alcohol / propylene glycol = 69.2 mass part / 15 mass part / 15.8 mass part) was apply | coated to the band surface side of a transparent support body, and it is a state of about 40 degreeC After holding for 30 seconds, the alkaline liquid was scraped off, washed with pure water, and the water droplets were cleaned with an air knife. Then, it dried for 15 second at 100 degreeC. It was 42 degrees when the contact angle with respect to the pure water of the alkali treatment surface was measured. After apply | coating the same coating liquid for optically anisotropic layer formation used in Example 1-1, and forming the optically anisotropic layer to the said support body, it bonded by the polarizing film and roll to roll so that an application surface might turn outward. The rest of the configuration was the same as in Example 1-1.

Example 1-3

The liquid crystal display device of the structure similar to the structure shown in FIG. 1 was produced. That is, from the observation direction (upper) from the outer protective film (1), the polarizing film (3), the support (5), the optical compensation film (7), the liquid crystal cell (9), the liquid crystal layer (11), the lower substrate (13), The optical compensation film 14, the lower polarizing plate protective film 16, and the lower polarizing film outer protective film 20 are laminated, and an optical simulation is performed on the liquid crystal display device having a configuration in which the backlight light source 22 is arranged. Was confirmed. As optical calculations, LCD Master Ver 6.08 manufactured by Syntec Corporation was used. The liquid crystal cell, an electrode, a board | substrate, a polarizing plate, etc. used the value of the material conventionally used for liquid crystal displays as it is. The orientation of the liquid crystal cell is a pretilt angle of 3 degrees for both the upper and lower substrates, the cell gap of the substrate is 5.2 microns, and the retardation of the liquid crystal (ie, the product of the thickness d (micron) of the liquid crystal layer and the refractive index anisotropy Δn) d) was 385 nm at wavelength 550 nm and 400 nm and wavelength 633 nm. C light source attached to LCD Master was used as the light source. In addition, in the liquid crystal display of the configuration shown in Fig. 1, even if the relationship between the backlight and the observer is changed up and down, the same result is obtained. Under the above conditions, simulation was performed by changing the Re and Rth of the support, and the Re and Rth of the support were changed to track the change behavior of the contrast ratio at 60 ° downward.

The value of the contrast ratio in 60 degrees of downwards when Re and Rth of a protective film is changed is shown in FIG. In the same figure, it was found that when 25 + Re (633) ≤ Rth ≤ 250-Re (633), the contrast ratio was 10 or more and a high contrast characteristic was obtained.

If it calculates in detail, it is 25 + Re (633) <= Rth <= 175 + Re (633), and the range of Rth <= 250-Re (633) is preferable. When more detailed calculations were made, it was found that when 50 + Re (633) ≤ Rth ≤ 150 + Re (633) and Rth ≤ 150-Re (633), contrast 10 or more was obtained at a viewing angle of 80 °.

Moreover, it turned out that half or less of retardation (DELTA) nd of a liquid crystal layer is preferable for the absolute value of Re 5nm or more and Re and Rth.

Comparative Example 1-1

In Example 1-1, it arrange | positioned so that the absorption axis of a polarizing film and the slow axis (parallel direction and parallel direction) of the support body of an optical compensation sheet may become parallel.

(Evaluation in TN Liquid Crystal Cell)

A pair of polarizing plates formed on a liquid crystal display device (AQUOS LC20C1S, manufactured by Sharp Co., Ltd.) using a TN-type liquid crystal cell is peeled off, and the direction of retardation of the liquid crystal layer and twisting of the liquid crystal is manufactured by Syntec Co., Ltd. It was measured using the deflection analyzer H 33. It was confirmed that the retardation was about 0.4 μm, and the liquid crystal cell was twisted about 90 ° clockwise from the observation side toward the display observation side from the light source side. Instead of the polarizing plate peeled off, the polarizing plates produced in Examples 1-1 and 1-2 and the polarizing plates produced in Comparative Example 1-1 were placed one by one on the observer side and the backlight side through the adhesive such that the optical compensation film was on the liquid crystal cell side. Adhesion.

About the produced liquid crystal display device, the viewing angle was measured in 8 steps from a black display (L0) to a white display (L7) using a measuring instrument (EZ-Contrast 160D, manufactured by ELDIM). For the liquid crystal display devices of Examples 1-1 to 2 and Comparative Example 1-1, the viewing angles of the upper, lower, left, and right that the contrast ratio is 10 or more are shown in Table 1-1.

TABLE 1-1

Normal viewing angle Hasashiak Left field of view Wuxi angle Lower half Front contrast Example 1-1 85 ° 80 ° 80 ° 80 ° 31 ° 550 Example 1-2 85 ° 85 ° 85 ° 85 ° 35 ° 520 Example 1-4 80 ° 60 ° 70 ° 70 ° 30 ° 530

Viewing angle: Polar angle in the normal direction of the contrast ratio 10 or more

Lower half angle: The angle at which the luminance values of L1 and L2 are reversed.

Example 1-1 is an example using the polarizing plate whose slow axis of a support body was orthogonal to the absorption axis of a polarizing film, and Example 1-2 similarly produced the polarizing plate whose slow axis of a support body was orthogonal to the absorption axis of a polarizing film by roll to roll. It is an example using the polarizing plate. As described above, Example 1-3 tracked the change behavior of the contrast ratio by changing the Re and Rth of the support by simulation with respect to the model using the polarizing plate whose slow axis of the support was orthogonal to the absorption axis of the polarizing film. Yes. Although the contrast viewing angles are good in all of Examples 1-1 to 1-4, Examples 1-1 to 1-3, which are examples of using a polarizing plate whose slow axis of the support is perpendicular to the absorption axis of the polarizing film, particularly show that the contrast viewing angle is enlarged. okay.

Example 2-1

Optical simulation was performed about the liquid crystal display device of the structure shown in FIG. 3, and the effect was confirmed. Synthetic LCD Master Ver 6.08 was used for optical calculation. The liquid crystal cell, an electrode, a board | substrate, a polarizing plate, etc. can use what is conventionally used for liquid crystal displays as it is. ZLI-4792 attached to the LCD Master was used for the liquid crystal material. The orientation of the liquid crystal cell is the horizontal orientation of the parallel orientation at a pretilt angle of 4 degrees, the cell gap of the substrate is 4 microns, and the retardation of the liquid crystal with a liquid crystal material having positive dielectric anisotropy (that is, the thickness d of the liquid crystal layer ( Micron) and the product of refractive index anisotropy (Δn) (Δn · d)) were 395 nm. G 1220 DU attached to LCD Master was used for the polarizing film. In the transparent film, the values of Re and Rth in wavelength were set to the values shown in the column of Example 2-1 of Table 2-1. In addition, the front side retardation value of the optically anisotropic layer was set to 30 nm. As a light source, a backlight light source attached to the LCD Master was used. In this way, the liquid crystal display of Example 2-1 was set as the structure shown in FIG. However, the crossing angle between the transmission axis 51a of the polarizing film 51 and the in-plane slow axis 53a of the transparent film 53, and the transmission axis 61a of the polarizing film 61 and the transparent film 63 The crossing angle with in-plane slow axis 63a was 0 degrees, respectively.

<Leakage light and chromaticity of liquid crystal display device>

To the liquid crystal display of Example 2-1, a voltage having the smallest transmittance at the front, i.e., a black voltage, was applied, and the black display transmittance (%) at the azimuth angle 270 ° and the polar angle 60 ° direction viewing angle at that time was applied. Obtained. The results are shown in Table 2-1.

[Examples 2-2 to 2-4]

In the same manner as in Example 2-1, Re and Rth of the transparent film were set so as to have the optical characteristics shown in Table 2-1. Otherwise, the optical characteristics of the liquid crystal display device were calculated and calculated by the LCD Master in the same manner as in Example 2-1.

<Measurement of leakage light and chromaticity of liquid crystal display device>

To these liquid crystal display devices, a voltage having a smallest transmittance at the front, i.e., a black voltage, was applied, and the black display transmittance (%) at the azimuth angle 270 ° and the polar angle 60 ° direction viewing angle at that time was obtained. The results are shown in Table 2-1.

Comparative Example 2-1

In the same manner as in Example 2-1, Re and Rth of the transparent film were set so as to have the optical characteristics shown in Table 2-1. Other than that, the optical characteristic of the liquid crystal display device was calculated by the LCD Master in the same manner as in Example 2-1. In the comparative example 2-1, Re / Rth which is ratio of Re and Rth was made to become substantially constant in any wavelength of 450, 550, 650 nm for the comparison with the effect of the 2nd aspect of this invention.

<Measurement of leakage light and chromaticity of liquid crystal display device>

To these liquid crystal display devices, a voltage having a smallest transmittance at the front, i.e., a black voltage, was applied, and the black display transmittance (%) at the azimuth angle 270 ° and the polar angle 60 ° direction viewing angle at that time was obtained. The results are shown in Table 2-1.

Table 2-1: Black transmittance (%) at 270 ° azimuth and 60 ° viewing angle

TABLE 2-1

From the results shown in Table 2-1, Re / Rth (450 nm) is 0.39-0.95 times that of Re / Rth (550 nm), and Re / Rth (650 nm) is 1.04-2.20 of Re / Rth (550 nm). In Examples 2-1 to 2-4, which are liquid crystal display devices according to the second aspect of the present invention, the transmittance at the time of black display at a polar angle of 60 ° is lower than that in Comparative Example 2-1. It can be seen that. In addition, from the result of Table 2-1, when Re / Rth (450 nm) is 0.56 times Re / Rth (550 nm), and Re / Rth (650 nm) is 1.69 times Re / Rth (550 nm) It can be understood that the minimum, together with the transmittance and color shift.

The polarizing plate according to the first aspect of the present invention has an optically anisotropic layer containing a disk-shaped compound fixed in a hybrid alignment state, and a protective film satisfies predetermined optical characteristics. The polarizing plate contributes to enlargement of the contrast viewing angle of the liquid crystal display device. The wider viewing angle also improves other viewing angle characteristics, such as gradation inversion. And by providing the function of an optical compensation film to a polarizing plate protective film, it becomes possible to improve the contrast fall at the time of bonding, to reduce the thickness of a device, and to reduce the curvature and the unevenness of a display apparatus at the time of a change.

In addition, the optical compensation film according to the second aspect of the present invention is a transparent film having an optical optimum value by independently controlling the wavelength dispersion of in-plane retardation and retardation in the thickness direction by appropriately selecting a material or a manufacturing method. Have By using this optical compensation film, the visual compensation of the black state of a liquid crystal cell, especially a TN mode liquid crystal cell is attained at almost all wavelengths. As a result, in the liquid crystal display device having such an optical compensation film, the lack of light in the oblique direction at the time of black display is reduced, and the viewing angle contrast is remarkably improved. In addition, since such a liquid crystal display device can suppress the lack of light in the oblique direction at the time of black display in almost all visible light wavelength ranges, it is possible to improve the color shift at the time of black display depending on the viewing angle which was a conventional problem.

Claims (11)

A liquid crystal display device comprising: a pair of substrates having electrodes on at least one side and opposed to each other; a liquid crystal layer formed between the pair of substrates; and a first polarizing plate disposed outside the liquid crystal layer; The product (Δn · d) of the thickness d (μm) of the liquid crystal layer and the refractive index anisotropy (Δn) is 0.2 to 1.2 μm, and the alignment state of the liquid crystal layer is changed by applying an electric field of two or more values, and when an electric field is applied. And the average orientation inclination angle with respect to the substrate surface of the liquid crystal layer when the electric field is not applied, The first polarizing plate contains a polarizing film, a pair of protective films sandwiched by the polarizing film, and a disk-shaped compound fixed in a hybrid alignment state located outside of the protective film and closer to the liquid crystal layer. Has an optically anisotropic layer, A liquid crystal display device in which at least one of the pair of protective films satisfies the following formula (I). (I) 25 + Re (633) ≤Rth≤250-Re (633) [Wherein Re (λ) is the front retardation value (unit: nm) at wavelength λ nm, and Rth (λ) is the retardation value (unit: nm) in the film thickness direction at wavelength λ nm. D is the thickness of the film.] The method of claim 1, A liquid crystal display device in which at least one of the protective films satisfies the following formula (II). (II) 5≤ | Re (633) | The method according to claim 1 or 2, At least one of Re and Rth of (DELTA) nd of the said liquid crystal layer and the said protective film satisfy | fills following formula (III) and (IV) in wavelength 400-700nm. (III) Rth≤Δnd / 2 (IV) Re≤Δnd / 2 The method according to any one of claims 1 to 3, And a slow axis of the protective film close to the liquid crystal layer and the polarizing film absorption axis. A polarizing film, a pair of protective films arranged to sandwich the polarizing film, and an optically anisotropic layer which is disposed outside the protective film and contains a disk-like compound fixed in a hybrid alignment state, wherein at least one of the pair of protective films One polarizer satisfies the following formula (I). (I) 25 + Re (633) ≤Rth≤250-Re (633) [Wherein, Re (λ) is the front retardation value (unit: nm) at the wavelength λ nm, and Rth (λ) is the retardation value (unit: nm) in the film thickness direction at the wavelength λ nm. D is the thickness of the film.] The method of claim 5, A polarizing plate formed by bonding the polarizing film and the pair of protective films in a roll to roll. An optical compensation film having a transparent film and an optically anisotropic layer having optical anisotropy in the plane, When the in-plane retardation of the transparent film is Re and the retardation in the thickness direction is Rth, the ratio Re / Rth (450 nm) of Re and Rth at a wavelength of 450 nm is equal to Re / Rth at a wavelength of 550 nm. 550 nm), 0.39 to 0.95 times, Re / Rth (650 nm) at wavelength 650 nm, 1.04 to 2.20 times Re / Rth (550 nm), and Rth at wavelength 550 nm is 70 nm to 400 nm. , The optically anisotropic layer is formed of a composition containing a liquid crystalline compound, wherein molecules of the liquid crystalline compound in the optically anisotropic layer are fixed in an alignment state, and at least at the transparent film side interface of the molecular symmetry axis of the liquid crystalline compound. An optical compensation film having an intersection angle between a direction in which an orientation average direction is orthogonal in the plane of the transparent film and a slow axis in the plane of the transparent film is about 0 degrees or about 90 degrees. The method of claim 7, wherein The optical compensation film, wherein the liquid crystalline compound is a discotic liquid crystalline compound. A pair of substrates opposed to each other having an electrode on at least one side, and a pair of substrates sandwiched between the pair of substrates and containing a nematic liquid crystal material, wherein liquid crystal molecules of the nematic liquid crystal material are non-driving on the surfaces of the pair of substrates. A liquid crystal cell having a liquid crystal layer oriented approximately parallel to, and having a product (Δn · d) of thickness d (micron) and refractive index anisotropy (Δn) of 0.1 to 1.5 microns, First and second polarizing films arranged to sandwich the liquid crystal cell, and Having a transparent film between at least one of the first and second polarizing films and the liquid crystal cell, When the in-plane retardation of the transparent film is Re and the retardation in the thickness direction is Rth, the ratio Re / Rth (450 nm) of Re and Rth at a wavelength of 450 nm is equal to Re / Rth at a wavelength of 550 nm. 550 nm), 0.39 to 0.95 times, Re / Rth (650 nm) at wavelength 650 nm, 1.04 to 2.20 times Re / Rth (550 nm), and Rth at wavelength 550 nm of the transparent film, 70 Nm to 400 nm, At least one optically anisotropic layer is provided between the said transparent film and the said liquid crystal cell, The said optically anisotropic layer is formed from the composition containing a liquid crystalline compound, The molecule | numerator of the said liquid crystalline compound in the said optically anisotropic layer is an orientation state And a cross angle between the direction in which the orientation average direction at the interface of the transparent film side of the molecular symmetry axis of the liquid crystalline compound is orthogonally projected in the plane of the transparent film and the slow axis in the plane of the transparent film is about 0 degrees. Or about 90 degrees. The method of claim 9, Liquid crystal display device wherein the liquid crystal compound is a discotic liquid crystal compound The method according to claim 9 or 10, And a liquid crystal cell of TN mode.

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