JP2002243942A - Method for manufacturing elliptically polarizing plate for viewing angle compensation, elliptically polarizing plate for viewing angle compensation, and liquid crystal display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an elliptically polarizing plate for viewing angle compensation and an optical compensation sheet capable of simply improving the viewing angle characteristics of a TN LCD(twisted nematic liquid crystal display device) such as TN-TFT(twisted nematic-thin film transistor), and further to provide a liquid crystal display device with a simple construction and with a drastically improved viewing angle. SOLUTION: The elliptically polarizing plate for the viewing angle compensation provided with a polarizing plate A, an optically anisotropic layer and a transparent supporting body C with optically biaxial property, the elliptic is characterized by being manufactured via steps (1), (2). The optically anisotropic layer is formed on the polarizing plate A, directly or via another transparent supporting body (1), and subsequently the transparent supporting body C with the optically biaxial property is provided on the optically anisotropic layer directly or via another layer (2).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a viewing angle compensation elliptically polarizing plate, an optical compensation film using the same, and a liquid crystal display.

[0002]

2. Description of the Related Art At present, personal computers are becoming more multimedia, and color display has become common in laptop personal computers. In the above-mentioned laptop computers and desktop monitors, STN liquid crystal displays and TFT liquid crystal displays are mainly used. In recent years, liquid crystal displays have become larger and simultaneously have excellent display quality.
T liquid crystals have become mainstream, and a high degree of improvement in viewing angle characteristics has been demanded. For that purpose, as a display mode of a TFT type liquid crystal, not only a conventional TN type but also an in-plane switching mode (IP
S), vertical alignment method (VA) and the like have been proposed and put into practical use. On the other hand, the TN-type TFT liquid crystal has a feature of high light use efficiency because of its low manufacturing cost and optical rotation mode.
With the advent of the optical compensation film in recent years, the viewing angle characteristics have been improved, and the film has been widely used.

The following three types of configurations have been tried as optical compensation films used for expanding the viewing angle of a liquid crystal display device, and each has been proposed as an effective method.

(1) A method of supporting a discotic liquid crystal compound, which is a compound having a negative uniaxial property described above, on a support, specifically, as disclosed in JP-A-7-191217. Attempts have been made to improve the viewing angle characteristics of the liquid crystal cell by disposing discotic liquid crystal films on the upper and lower surfaces of the liquid crystal cell. The compensation film for a TN type liquid crystal display is disclosed in the above-mentioned JP-A-3-877.
No. 20, Japanese Patent Application Laid-Open No. 4-333019, like the retardation compensator of the liquid crystal display, comprises an optically anisotropic layer in which a liquid crystal compound is oriented on an optically almost isotropic resin film. ing.

(2) A method in which a nematic-type polymer liquid crystalline compound having positive optical anisotropy and having a hybrid orientation in which the pretilt angle of liquid crystal molecules changes in the depth direction is supported on a support.

(3) Two layers of a nematic liquid crystal compound having a positive optical anisotropy are formed on a support, and the orientation direction of each layer is set to approximately 90 °, whereby pseudo negative 1
A method of giving optical characteristics similar to axial properties.

[0007] For example, Japanese Patent Application Laid-Open No. Hei 8-15681 discloses a rod-shaped positive anisotropic layer formed using a positive uniaxial low-molecular liquid crystal compound having a rod-like orientation and having an alignment ability. Forming a layer comprising a uniaxial low-molecular liquid crystal compound of
A four-layer optical structure in which a layer made of a rod-shaped positive uniaxial low-molecular liquid crystal compound that is fixed and then re-oriented via an alignment layer having the re-alignment ability on this layer is further formed and fixed. An anisotropic layer is disclosed.

By giving the alignment directions projected on the plane of the two liquid crystal layers, for example, shifted by 90 degrees, it becomes possible to give a pseudo disk-like characteristic.

In this method, unlike the case of a discotic liquid crystal compound, there is no problem of coloring, so that the method has an advantage in quality in applications such as a liquid crystal TV (television) in which color reproduction is important. I have.

However, each of the configurations described above
It has the following problems. In the method described in the above (1), when applied to a TN mode liquid crystal panel, a disadvantage peculiar to a discotic liquid crystal compound that a screen when viewed from an oblique direction is colored yellow appears.

In the method described in (2), the liquid crystal development temperature is high, and the orientation of the liquid crystal cannot be fixed on an isotropic transparent support such as TAC (cellulose triacetate). After the orientation is fixed on the body, it is necessary to transfer to a support such as TAC, which complicates the process and extremely lowers the productivity.

In the case of the method described in the above (3), what was achieved with a single layer of the discotic liquid crystal compound is intentionally achieved with two liquid crystal layers, which is extremely inefficient. In addition, in order to orient the liquid crystal at right angles, in order to continuously produce an optical compensation film in a roll shape, for example, a method that can freely control the orientation direction of the liquid crystal in the film plane such as optical alignment is used. It had to be used, and there was a problem in productivity.

In recent years, the development of liquid crystal display devices not only for conventional monitors for personal computers but also for entertainment applications such as TVs has progressed rapidly, and optical compensation films satisfying the demand for higher quality and lower cost have been obtained. Did not.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to provide a TN
-Viewing angle characteristics of a TN type LCD such as a TFT,
Liquid crystallinity that uses an optically biaxial support for use in an optical compensation film that can improve the contrast, coloration, and reversal of light and dark when viewed from an oblique direction, and that is oriented and fixed. An object of the present invention is to provide a polarizing plate (herein, referred to as a viewing angle compensating polarizing plate) having extremely excellent optical compensation ability even when the compound has a low pretilt angle.

[0015]

The above objects of the present invention have been attained by the following items 1 to 21.

1. Polarizing plate A, a liquid crystal compound is oriented in a specific direction, an optically anisotropic layer formed by fixing, and a viewing angle compensation elliptically polarizing plate having a transparent support C having optical biaxiality, the following: A viewing-angle-compensating elliptically polarizing plate manufactured through the steps (1) and (2).

(1) The optically anisotropic layer is formed directly on the polarizing plate A or via another transparent support,
(2) On the optically anisotropic layer, the optically biaxial transparent support C is provided directly or via another layer.

2. A first transparent support, a polarizer, a second transparent support, an optically anisotropic layer formed by fixing the orientation of a liquid crystalline compound, and a transparent support C having optical biaxiality in this order. A viewing angle compensating elliptically polarizing plate, comprising: the viewing angle compensating elliptically polarizing plate manufactured through the following steps (1), (2) and (3).

(1) Orienting a liquid crystalline compound directly on the second transparent support or via the third transparent support,
An optically anisotropic layer is formed by immobilization. (2) The side of the second transparent support on which the optically anisotropic layer is not applied faces the first transparent support so that the polarizer is sandwiched therebetween. Deploy,
Next, (3) a transparent support C having optical biaxiality is provided on the optically anisotropic layer directly or via another layer.

3. A first transparent support, a polarizer, a second transparent support, an optically anisotropic layer formed by fixing the orientation of a liquid crystalline compound, and a transparent support C having optical biaxiality in this order. A viewing angle compensating elliptically polarizing plate, comprising: the viewing angle compensating elliptically polarizing plate manufactured through the following steps (1), (2) and (3).

(1) Orienting a liquid crystalline compound directly on the second transparent support or via the third transparent support,
Immobilizing to form an optically anisotropic layer; (2) providing a transparent support C having optical biaxiality directly or via another layer on the optically anisotropic layer; The side of the transparent support on which the optically anisotropic layer is not applied faces the first transparent support, and is disposed so as to sandwich the polarizer.

4. If R _{t (bi)} / R 0 _{of (bi)} of the transparent support C having an optical biaxial property exceeds 1.4, the R _t value of the second transparent substrate is 60nm or less 4. The viewing angle compensating elliptically polarizing plate according to any one of the above items 1 to 3, which is characterized by the following.

5. If R _{t (bi)} / R 0 _{of (bi)} of the transparent support C having an optical biaxial property exceeds 2.0, the R _t value of the second transparent substrate is 35nm or less 4. The viewing angle compensating elliptically polarizing plate according to any one of the above items 1 to 3, which is characterized by the following.

6. Optically biaxial transparent support C
6. The viewing angle compensating elliptically polarizing plate according to any one of the above items 1 to 5, wherein the R ₀ value is from 20 nm to 95 nm.

[7] Optically biaxial transparent support C
6. The viewing angle compensating elliptically polarizing plate according to any one of the above items 1 to 5, wherein the R ₀ value is from 45 nm to 75 nm.

8. In the method for producing a polarizing plate A, an optically anisotropic layer formed by orienting and fixing a liquid crystal compound in a specific direction, and a transparent support C having optical biaxiality, a viewing angle compensation elliptically polarizing plate is provided. , The following step (1),
(2) A method for producing a viewing angle compensating elliptically polarizing plate, characterized by having (2).

(1) The optically anisotropic layer is formed directly on the polarizing plate A or via another transparent support,
(2) The transparent support C having optical biaxiality is provided on the optically anisotropic layer.

9. A first transparent support, a polarizer, a second transparent support, an optically anisotropic layer formed by fixing the orientation of a liquid crystalline compound, and a transparent support C having optical biaxiality in this order. A method for manufacturing a viewing angle compensating elliptically polarizing plate, comprising the following steps (1), (2) and (3).

(1) Orienting a liquid crystalline compound directly on the second transparent support or via the third transparent support,
An optically anisotropic layer is formed by immobilization. (2) The side of the second transparent support on which the optically anisotropic layer is not applied faces the first transparent support so that the polarizer is sandwiched therebetween. Deploy,
Next, (3) a transparent support C having optical biaxiality is provided on the optically anisotropic layer directly or via another layer.

10. A first transparent support, a polarizer, a second transparent support, an optically anisotropic layer formed by fixing the orientation of a liquid crystalline compound, and a transparent support C having optical biaxiality in this order. A method for manufacturing a viewing angle compensating elliptically polarizing plate, comprising the following steps (1), (2) and (3).

(1) Orienting a liquid crystalline compound directly on the second transparent support or via the third transparent support,
Immobilizing to form an optically anisotropic layer; (2) providing a transparent support C having optical biaxiality directly or via another layer on the optically anisotropic layer; The side of the transparent support on which the optically anisotropic layer is not applied faces the first transparent support, and is disposed so as to sandwich the polarizer.

11. Transparent support C having optical biaxiality
Of R _{t (bi)} / R 0 when _{the (bi)} value exceeds 1.4, any one of the 8 to 10 R _t value of the second transparent substrate is equal to or is 60nm or less 13. The method for producing a viewing angle-compensated elliptically polarizing plate according to item 13.

12. Transparent support C having optical biaxiality
Of R _{t (bi)} / R 0 when _{the (bi)} value exceeds 2.0, any one of the 8 to 10 R _t value of the second transparent substrate is equal to or is 35nm or less 13. The method for producing a viewing angle-compensated elliptically polarizing plate according to item 13.

13. The method for producing a viewing angle compensating elliptically polarizing plate according to any one of the above items 8 to 12, wherein the optically biaxial transparent support C has an R ₀ value of 20 nm to 95 nm.

14. The method for producing a viewing angle compensation elliptically polarizing plate according to any one of the above items 8 to 12, wherein the optically biaxial transparent support C has an R ₀ value of 45 nm to 75 nm.

15. A liquid crystal display device comprising the viewing angle compensating elliptically polarizing plate according to any one of the above items 1 to 7.

16. A liquid crystal display device having, on both sides of a liquid crystal cell, a transparent support C having optically biaxial properties, an optically anisotropic layer formed by aligning and fixing a liquid crystal compound, and a polarizer in this order. .

17. Optically biaxial on both sides of the liquid crystal cell
Support C having a polymer, liquid crystal compound is aligned and fixed
Formed optically anisotropic layer, second transparent support, polarized light
And a first transparent support in this order.
R of optically biaxially transparent support C_{t (bi)}/ R
_{0 (bi)}If the value exceeds 1.4, the second transparent support
R _tLiquid crystal display having a value of not more than 60 nm
apparatus.

18. Optically biaxial on both sides of the liquid crystal cell
Support C having a polymer, liquid crystal compound is aligned and fixed
Formed optically anisotropic layer, second transparent support, polarized light
And a first transparent support in this order.
R of optically biaxially transparent support C_{t (bi)}/ R
_{0 (bi)}If the value exceeds 2.0, the second transparent support
R _tLiquid crystal display characterized in that the value is 35 nm or less
apparatus.

19. Wherein the second transparent support is disposed between the optically anisotropic layer and the polarizer.
19. The liquid crystal display device according to any one of 18.

20. 20. The liquid crystal display device according to any one of the items 15 to 19, wherein the optically biaxial transparent support C has an R _{0 (bi)} value of 20 nm to 95 nm.

21. 20. The liquid crystal display device according to any one of the above items 15 to 19, wherein the optically biaxial transparent support C has an R _{0 (bi)} value of 45 nm to 75 nm.

Hereinafter, the present invention will be described in detail. The viewing angle compensation elliptically polarizing plate of the present invention will be described.

The viewing angle compensating elliptically polarizing plate of the present invention has a laminated structure, and a typical example is a first transparent support (usually a cellulose triacetate film) -a polarizer-a second transparent substrate. Support (usually a cellulose ester film)-an optically anisotropic layer formed by fixing the orientation of a liquid crystalline compound in a specific direction-a transparent support C having optical biaxiality (for example, a stretched cellulose ester film) After forming an optically anisotropic layer directly or indirectly on the second transparent support, a transparent support C having optical biaxiality is disposed on the optically anisotropic layer. It is formed by this.

The transparent support C having optical biaxiality described above is defined as follows: the maximum in-plane refractive index is nx, the refractive index in a direction perpendicular to the in-plane direction is ny, and the refractive index in the thickness direction is nz. , Nx>ny> nz, and may be referred to as an optically negative biaxial support or an optically negative biaxial film.

Specifically, as an example of the first transparent support and the second transparent support described above, a cellulose triacetate film having a thickness of 40 μm to 80 μm, which is produced by a casting method, is used. The polarizer is obtained by stretching iodine-doped polyvinyl alcohol, and the polarizer is laminated with the first transparent support and the second transparent support to form a polarizing plate.

The optically anisotropic layer is a layer in which a liquid crystalline compound having a polymerizable group is placed on a support provided with an alignment ability by rubbing or the like by coating or the like, and is fixed by, for example, curing with ultraviolet rays. is there. Further, as the transparent support C having optical biaxiality, a stretched cellulose ester film having a thickness of preferably 40 to 150 μm can be used.

From the viewpoint of productivity, in the case of performing continuous production, a cellulose ester film stretched in the width direction is preferably used as the optically biaxially transparent support C according to the present invention. In this case, the viewing angle compensating elliptically polarizing plate of the present invention can be directly laminated and roll-to-rolled by orienting the liquid crystal compound in the transport direction of the long second transparent support. it can.

A method for manufacturing a viewing angle compensating elliptically polarizing plate according to the present invention will be described. As a procedure for manufacturing the viewing angle compensation elliptically polarizing plate according to the present invention, the optically anisotropic layer is formed directly or indirectly on a transparent support, and the optically anisotropic layer surface has optical biaxiality. There is no particular limitation as long as the transparent support C having the same is arranged.

Here, a method for manufacturing the viewing angle compensating elliptically polarizing plate of the present invention will be specifically described with reference to FIGS.

FIG. 2 is a schematic sectional view showing one step of a method for manufacturing a viewing angle compensating elliptically polarizing plate according to the present invention. FIG.
In (a), first, a transparent support 21b similar to the transparent support 21a is saponified with an alkali, and then laminated so that the polarizer 22 is sandwiched therebetween, thereby producing a polarizing plate A. Then
As shown in FIG. 2B, a layer containing a liquid crystal compound 10 having a polymerizable group is applied on the surface of the transparent support 21b to provide alignment ability, and the liquid crystal is aligned by, for example, rubbing. After that, it is fixed and the optically anisotropic layer 23 is formed.

Here, the liquid crystal compound 10 shown in FIG. 2B has a small pretilt angle and the transparent support 21b
In the vicinity of the interface between the transparent support 21b and the optically anisotropic layer 23, the tilt angle is small, but the tilt angle is large as the distance from the interface of the transparent support 21b is increased. I have.

Next, as shown in FIG. 2C, an optically biaxial transparent support 2 is formed on the surface of the optically anisotropic layer 23.
By providing 4, the viewing angle compensating elliptically polarizing plate of the present invention can be manufactured. When providing the optically biaxially transparent support 24 on the side of the optically anisotropic layer 23, the support may be bonded via an adhesive layer or an adhesive layer.

FIG. 3 is a schematic sectional view showing another step of the method for producing a viewing angle compensating elliptically polarizing plate according to the present invention. In FIG. 3A, first, a transparent support 21b is prepared,
As shown in FIG. 3B, an alignment layer (not shown here) is applied on the transparent support 21b, and after rubbing, a liquid crystal compound layer having a polymerizable group is applied, aligned, and fixed. To form an optically anisotropic layer 23.

Next, as shown in FIG. 3C, both the transparent support 21b having the optically anisotropic layer 23 and the separately prepared transparent support 21a were alkali-saponified, and then the polarizer 2 was used.
After the polarizing plate A is manufactured by laminating the polarizing plate A so as to sandwich the transparent supporting member 2, an optically biaxial transparent support is disposed on the side of the polarizing plate A having the optically anisotropic layer. An angle-compensated elliptically polarizing plate can be manufactured. Moreover, when bonding an optically biaxial transparent support, the support may be bonded via an adhesive layer or an adhesive layer.

Here, the optically biaxial property according to the present invention is provided.
The viewing angle characteristics are slightly affected by the optical characteristics of the transparent support
Although there is a difference in the results, the arrangement between the polarizer and the optically anisotropic layer
The transparent support to be placed is, for example, a cellulose ester filter.
If only a second transparent support, such as
It is preferable to have the following optical characteristic values. Sand
That is, the thickness of the optically biaxial transparent support in the thickness direction is reduced.
The retardation value (R _{t (bi)}) And in-plane retardation
Value (R_{0 (bi)}) Ratio R_{t (bi)}/ R_{0 (bi)}Exceeds 1.4
The thickness of the second transparent support in the thickness direction.
Option (R_t) Value less than 60 nm, preferably 35 n
m or less, more preferably 20 nm or less, still more preferably
Excellent visual field by adjusting to 0 to 10 nm or less
An angular characteristic can be obtained.

The ratio of the retardation value (R _{t (bi )} ) in the thickness direction of the optically biaxially transparent support to the in-plane retardation value (R _{0 (bi)} ) R _{t (bi)} /. When the value of R _{0 (bi)} exceeds 2.0, the retardation (R _t ) value in the thickness direction of the second transparent support is 35 nm or less, preferably 30 nm or less, more preferably 20 nm or less, More preferably, by adjusting it to 0 to 10 nm or less,
Excellent viewing angle characteristics can be obtained.

The value of R _{t (bi)} / R _{0 (bi)} is preferably 5.0 or less, more preferably 3.0 or less, and most preferably 2.5 or less.

R of an optically biaxial transparent support
_{0 (bi)} is preferably 20 nm to 95 nm, preferably 3 nm.
0 nm to 90 nm, more preferably 40 nm
-85 nm, more preferably 45-75 nm.

When there are a plurality of transparent supports disposed between the polarizer and the optically anisotropic layer, the total of the retardation values (R _t ) in the thickness direction is within the above range. It is preferred that

Here, R _{0 (bi)} and R _{t (bi)} indicate retardation values of an optically biaxial transparent support defined by the following formulas (a) and (b).

(A) R _{0 (bi)} = (nx−ny) × d (b) R _{t (bi)} = ((nx + ny) / 2−nz) × d where nx is the maximum refraction in the plane. The refractive index in the x direction, which is the index direction, and ny is the refractive index in the y direction, which is a direction orthogonal to the x direction in the plane. nz is the refractive index in the thickness direction, and d is the thickness (nm).

Hereinafter, each component will be described.
As the optically biaxially transparent support according to the present invention, for example, a cellulose ester film, particularly a cellulose acetate propionate film, is preferably used in exactly the same manner as described in Japanese Patent Application No. 2000-372741.

The total degree of substitution of the cellulose ester is 2.55
To 2.85 is preferred, and when using cellulose acetate propionate, the degree of acetyl substitution is 1.5 to 2.5;
The degree of propionyl substitution is preferably from 0.1 to 1.2.

For example, cellulose acetate propionate having an acetyl substitution degree of 2.0 and propionyl substitution degree of 0.8, or cellulose acetate propionate having an acetyl substitution degree of 1.9 and propionyl substitution degree of 0.7 is preferably used. .

These films were prepared by casting the film by appropriately optimizing the conditions in the same manner as in the case where the transparent supports 1 and 2 described later were cellulose ester films.
It can be produced by adding a stretching step. The stretching step can be carried out simultaneously with the casting or after the casting.

As a method of stretching a film to be formed by casting, there are a method of stretching under heating conditions and a method of stretching under solvent-containing conditions. When stretching under heating conditions, it is preferred to stretch at a temperature near the glass transition point of the resin. In the case of a resin having an unclear glass transition point such as a cellulose ester, the temperature condition is not particularly limited as long as a certain stress is applied. When the cast film is stretched under the solvent impregnating condition, the dried film can be brought into contact with the solvent again to be impregnated with the solvent and stretched. After casting, stretching under the solvent remaining condition during drying (state with residual solution) is preferable from the viewpoint of reducing the number of steps and the uniformity of the solvent impregnation state.

For example, in the case of a cellulose ester film, optically biaxial properties can be imparted by stretching the film while maintaining the width in uniaxial stretching or the free-end uniaxial stretching at an appropriate stretching ratio.

In the production of a stretched cellulose ester film according to the optical compensation film of the present invention, a cellulose ester solution dope is cast on a casting support, and then
The web (film) peeled from the casting support is preferably stretched 1.0 to 3.0 times in the width direction while the amount of the residual solvent in the web is in the range of 10 to 100% by mass. .

The residual solvent amount can be determined by the following equation. Residual solvent amount (% by mass) = {(M−N) / N} × 100 where M is the mass of the web at any time, and N is M
The mass when dried at 0 ° C. for 3 hours.

If the amount of the residual solvent in the web is too large, it is difficult to obtain the effect of stretching, and if it is too small, the stretching becomes extremely difficult, and the web may be broken. A more preferred range for the amount of residual solvent in the web is 10
Most preferred is from 50% by weight to 50% by weight, especially from 20% by weight to 40% by weight. On the other hand, if the stretching ratio is too small, a sufficient retardation cannot be obtained, and if it is too large, stretching becomes difficult and cloudiness or breakage may occur. A more preferred range of the stretching ratio is in the range of 1.01 to 2.5 times.

The solution cast film formed using the cellulose ester used in the present invention can be stretched without heating to a high temperature as long as the residual solvent content is within a specific range. It is also possible. However, if the temperature of the web is too high, the plasticizer volatilizes, so that the room temperature (15
C) to 160C or less.

The film thickness may decrease with stretching.
If the film thickness fluctuation of the cellulose ester film support is too large, the phase difference becomes uneven, which causes problems such as coloring when used as an optical compensation film. The thickness distribution of the cellulose ester film support is preferably in the range of ± 3%, more preferably ± 1%. For the purpose as described above, the method of stretching in biaxial directions orthogonal to each other is effective, and the stretching ratio in biaxial directions orthogonal to each other is 0.8 to 0.8.
It is preferable to set the range to 4.0 times, 0.4 to 1.2 times.

The method for stretching the web is not particularly limited. For example, fix both ends of the web with clips or pins,
A method of spreading the clip or pin in the horizontal direction and extending it in the horizontal direction, a method of expanding the clip or pin simultaneously in the vertical and horizontal directions and extending in both the vertical and horizontal directions, and a method of expanding it in the width direction and shrinking it in the transport direction can be used. Of course, these methods may be used in combination. Stretching to TD and shrinking to MD
This is an effective method for setting the refractive indexes Nx, Ny, and Nz of the film within the scope of the present invention. In the case of the so-called tenter method, when the clip portion is driven by the linear drive method, smooth stretching is performed, and the risk of breakage or the like can be reduced, which is preferable.

In the film obtained as described above, the amount of the residual solvent in the final film is preferably 2% by mass or less, more preferably 0.4% by mass or less, particularly preferably 0.1% by mass or less. Is preferable for obtaining a film having good dimensional stability.

In the present invention, in the stretching in the width direction, since the film is stretched in the width direction while being conveyed, stress is applied in a complicated direction in the stretching process (the process of increasing the magnification). Including these, it refers to a stretching mode in which the film dimension extends in the width direction after a continuous stretching operation. In this case, both cases where the dimensional change in the transport direction is accompanied and cases where it is not accompanied are included.

When the film is stretched in the width direction as described above, the orientation angle may be distributed in the width direction. That is, the direction of the film having the maximum refractive index may deviate from the stretching direction. This may be seen, for example, when using the tenter method, but by stretching in the width direction, a contraction force is generated at the center of the film, and a phenomenon that occurs when the end is fixed, This is the so-called Boeing phenomenon. In this case, the bowing phenomenon can be suppressed by stretching or shrinking in the casting direction, or other stretching conditions such as heat and residual solution, and the distribution of the phase difference in the width direction can be reduced.

With regard to the production of the transparent support according to the present invention,
One example of a schematic diagram of a manufacturing apparatus will be described with reference to FIG. Figure 1
, The endless stainless belt 1 circulates between a low-temperature drying zone 3 and a high-temperature drying zone 4. The dope composition is cast from the die 2 onto the endless stainless belt 1 at the casting section 5, is conveyed in the direction of the arrow, is dried in the low-temperature drying zone 3 and the high-temperature drying zone 4, and is stripped.
The film is peeled from the endless stainless belt by the peeling roll 7 to form a cellulose ester film. The cellulose ester film further passes through the first drying zone 8, is transported from the second drying zone 13 to the third drying zone 11, and is wound by the winding unit 12 as a product. still,
The first drying zone 8 and the third drying zone 11 are transported by the transport rolls 9 in order to take a long path.

The thickness of the transparent support having optical biaxiality according to the present invention may be such that it has optical characteristics for improving the viewing angle characteristics of the liquid crystal display. The stretching ratio and the thickness of the transparent support are sufficient. Can be controlled by The thickness of the cellulose ester film support is preferably 25 μm
Not less than 250 μm, more preferably 40 μm
It is 140 μm or less. A conventionally known polarizer can be used. For example, a film obtained by treating a film made of a hydrophilic polymer such as polyvinyl alcohol with a dichroic dye such as iodine and stretching the film can be used.

Next, another transparent support according to claim 1, a first transparent support according to claim 2, and a second transparent support will be described.

The other transparent support, the first transparent support, and the second transparent support according to the present invention may be of the same type or different types. These are usually preferably optically isotropic or have no in-plane anisotropy, and such optical characteristics are particularly preferable for a transparent support that is disposed closer to the liquid crystal cell than the polarizer. Required. These transparent supports are not particularly limited as long as they satisfy such properties.Since they are easy to obtain adhesiveness with the polyvinyl alcohol of the polarizer, and have almost no optical in-plane anisotropy. Cellulose esters, especially cellulose triacetate, are preferably used.

As the cellulose ester used in the present invention, either a cellulose ester synthesized from cotton linter or a cellulose ester synthesized from wood pulp can be used alone or in combination. It is preferable to use a large amount of cellulose ester synthesized from cotton linter which has good releasability from a belt or a drum because the production efficiency is high. When the ratio of the cellulose ester synthesized from the cotton linter is 60% by mass or more, the effect of the releasability becomes remarkable, so that it is preferably 60% by mass or more, more preferably 85% by mass.
Most preferably, it is used in an amount of at least 1% by mass, and more preferably alone.

Next, a method for producing a film when the other transparent support, the first transparent support and the second transparent support according to the present invention are cellulose esters will be described.

First, a cellulose ester is dissolved in an organic solvent to form a dope. The concentration of the cellulose ester in the dope is preferably about 10 to 35% by mass.

Examples of the organic solvent include methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran,
3-dioxolan, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,
1,3,3,3-hexafluoro-2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro Non-chlorine organic solvents such as -1-propanol and nitroethane can be used. Also, methylene chloride can be used. It is preferable to use a lower alcohol such as methanol, ethanol, or butanol in combination because the solubility of the cellulose ester in an organic solvent can be improved and the viscosity of the dope can be reduced. Particularly, ethanol having a low boiling point and low toxicity is preferable. The lower alcohol is preferably contained in an amount of 4 to 30% by mass of the organic solvent used in the dope.

In the dope, additives such as the above-mentioned plasticizer, ultraviolet absorber and matting agent may be added. The dope is then cast on a rotating belt or drum support, dried until peelable, and the film is peeled. Stretched in the state of a peeled dry film,
The film can be further dried to evaporate the organic solvent in the film almost completely, but may be stretched after drying. The content of the organic solvent in the film is preferably 2% by mass or less, more preferably 0.4% by mass or less in order to obtain good dimensional stability of the film.

In the production of the transparent support according to the present invention, in particular, in order to improve the slip property in coating,
During the dope for producing these transparent supports, for example, silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin, talc, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, silicate It is preferable to include a matting agent such as inorganic fine particles such as magnesium and calcium phosphate and a crosslinked polymer. Among them, silicon dioxide is preferable because the haze of the film can be reduced. The fine particles preferably have an average secondary particle diameter of 0.01 to 1.0 μm and a content of 0.005 to 0.3% by mass based on the cellulose ester.

The fine particles such as silicon dioxide are preferably surface-treated with an organic substance, because the haze of the film can be reduced. Preferred organic substances in the surface treatment include halosilanes, alkoxysilanes, silazane,
Siloxane and the like. The average diameter of the fine particles is the same as the fine particles used in the anti-curl treatment described later.

The first and second transparent supports may curl if some stress and strain remain in the film. Therefore, an anti-curl layer can be provided on the side opposite to the coated optically anisotropic layer in order to prevent the curl and thereby eliminate the inconvenience caused by the curl and not to impair the function as an optically anisotropic layer. That is, the degree of curl is balanced by giving the property of trying to curl with the surface on which the anti-curl layer is provided inside. The anti-curl layer is preferably provided also as a blocking layer, and in such a case, the coating composition may contain inorganic fine particles and / or organic fine particles for imparting an anti-blocking function. For example, inorganic fine particles include silicon oxide, titanium oxide, aluminum oxide, tin oxide, zinc oxide, calcium carbonate, barium sulfate, talc, kaolin, calcium sulfate, and the like, and organic fine particles include polymethacrylic acid. Methyl acrylate resin powder, acrylic styrene resin powder, polymethyl methacrylate resin powder, silicon resin powder, polystyrene resin powder,
Polycarbonate resin powder, benzoguanamine resin powder, melamine resin powder, polyolefin resin powder,
Examples thereof include polyester resin powder, polyamide resin powder, polyimide resin powder, and polyfluoroethylene resin powder, which can be added to the anticurl layer coating composition. Fine particles such as silicon dioxide are preferably surface-treated with an organic substance because the haze of the film can be reduced. Preferred organic substances for the surface treatment include halosilanes, alkoxysilanes, silazanes, siloxanes and the like.

As fine particles of silicon dioxide, AEROSIL 200, 200V, 30 manufactured by Nippon Aerosil Co., Ltd.
0, R972, R974, R202, R812, OX5
0, TT600, etc., preferably AEROS
IL 200V, R972V, R974, R974V,
R202, R812 and the like.

These particles have a volume average particle size of 0.005
0.1 to 5 parts by mass of particles having a particle size of 0.1 to 0.1 μm is preferably added to 100 parts by mass of the resin composition. The fine particles are preferably blended such that the haze of the film is 0.6% or less and the dynamic friction coefficient between the front and back surfaces of the optically anisotropic body is 0.5 or less.

The fine particles can be provided as a layer containing a resin such as diacetyl cellulose. Such a layer can also be improved in strength by using a crosslinking agent such as an isocyanate derivative.

The anti-curl function is imparted by applying a composition containing a solvent for dissolving or swelling the resin film substrate. As a solvent to be used, in addition to a mixture of a solvent to be dissolved or a solvent to be swollen,
Further, a solvent that does not dissolve may be contained, and the composition is applied using a composition and an application amount in which these are mixed at an appropriate ratio depending on the curl degree of the resin film and the type of the resin. When it is desired to enhance the curl prevention function, it is effective to increase the mixing ratio of the solvent for dissolving or swelling the solvent composition to be used and to decrease the ratio of the solvent that does not dissolve. The mixing ratio is preferably (solvent to be dissolved or swellable) :( solvent not to be dissolved) = 10: 0 to 1: 9. As the solvent contained in such a mixed composition, for dissolving or swelling the resin film substrate, for example,
Benzene, toluene, xylene, dioxane, acetone, methyl ethyl ketone, N, N-dimethylformamide, methyl acetate, ethyl acetate, trichloroethylene, methylene chloride, ethylene chloride, tetrachloroethane, trichloroethane, chloroform and the like.
Examples of the solvent that does not dissolve include methanol, ethanol, n-propyl alcohol, i-propyl alcohol, and n-butanol.

A gravure coater was used to apply these coating compositions.
Using a dip coater, reverse coater, extrusion coater, etc., wet film thickness of 1 to 1 on the resin film surface
It is preferable to apply 00 μm, but it is particularly preferable to apply 5 to 30 μm. Examples of the resin used here include a vinyl chloride / vinyl acetate copolymer, a vinyl chloride resin, a vinyl acetate resin, a copolymer of vinyl acetate and vinyl alcohol, a partially hydrolyzed vinyl chloride / vinyl acetate copolymer, Vinyl-based polymers such as vinyl / vinylidene chloride copolymer, vinyl chloride / acrylonitrile copolymer, ethylene / vinyl alcohol copolymer, chlorinated polyvinyl chloride, ethylene / vinyl chloride copolymer, and ethylene / vinyl acetate copolymer Coalescence or copolymer, nitrocellulose, cellulose acetate propionate, diacetyl cellulose, cellulose ester resin such as cellulose acetate butyrate resin, copolymer of maleic acid and / or acrylic acid, acrylate copolymer, acrylonitrile / Styrene copolymer, salt Polyethylene,
Acrylonitrile / chlorinated polyethylene / styrene copolymer, methyl methacrylate / butadiene / styrene copolymer, acrylic resin, polyvinyl acetal resin, polyvinyl butyral resin, polyester polyurethane resin, polyether polyurethane resin, polycarbonate polyurethane resin, polyester resin, polyether Examples include, but are not limited to, resins, polyamide resins, amino resins, rubber resins such as styrene / butadiene resins, butadiene / acrylonitrile resins, silicone resins, and fluorine resins. Particularly preferred is a cellulose resin layer such as diacetyl cellulose.

When an optically biaxial transparent support is produced by stretching, a strain due to a larger stress may remain, and it is preferable to perform the same treatment.

Next, the rubbed alignment layer according to the present invention will be described. The rubbed alignment layer according to the present invention is disposed on the second transparent support, and is used for aligning and fixing the liquid crystalline compound in the optically anisotropic layer.

Here, the material constituting the alignment layer will be described. Specific examples include the following resins and substrates, but are not limited thereto. For example, polyimide, polyamide imide, polyamide, polyether imide, polyether ether ketone, polyether ketone, polyketone sulfide, polyether sulfone, polysulfone, polyphenylene sulfide, polyphenylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyacetal , Polycarbonate, polyarylate, acrylic resin, polyvinyl alcohol, polypropylene, cellulosic plastics, cellulose ester, epoxy resin, phenol resin and the like.

The alignment layer can be obtained by applying the above-mentioned alignment layer on the transparent resin substrate of the present invention, drying and setting the layer, and then performing a rubbing treatment.

A polyimide film (preferably polyimide containing a fluorine atom) which is widely used as an alignment layer for aligning a liquid crystal compound is also preferable as the alignment film. This is obtained by applying a polyamic acid (for example, LQ / LX series manufactured by Hitachi Chemical Co., Ltd., SE series manufactured by Nissan Chemical Co., Ltd.) on a transparent resin substrate, heat-treating, and then rubbing.

For the rubbing treatment, a treatment method widely used as a liquid crystal alignment treatment step of LCD can be used. That is, a method of rubbing the surface of the alignment film in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber or the like to obtain the alignment can be used. In general, rubbing is performed by using a cloth in which fibers having a uniform length and thickness are planted on average.

The rubbing treatment is preferably performed on the alignment layer from the viewpoint of maximizing the alignment ability, but may be performed directly on the transparent support.

Next, the liquid crystal compound according to the present invention will be described. A liquid crystal compound can be suitably used to realize such an optically anisotropic layer by controlling the alignment. Hereinafter, the liquid crystal compound according to the present invention will be described in detail.

The liquid crystal compound according to the present invention may be a low-molecular liquid crystal compound or a high-molecular liquid crystal compound. Optical properties include a positive uniaxial rod-like liquid crystalline compound,
Biaxial liquid crystal compounds are preferably used.

The compound having positive uniaxial optical anisotropy (also referred to simply as having positive uniaxial property) according to the present invention,
A biaxial compound exhibiting optical characteristics close to a rod-shaped liquid crystal compound can be treated as the optical characteristics of the rod-shaped liquid crystal compound, and can be included in the rod-shaped liquid crystal compound in the present invention.

In the case of an optically biaxial liquid crystal compound,
Two optical axes (not directions giving nx, ny, nz,
The angle between the optical axes) is greater than 0 ° and 20 °
The following are preferred.

Here, “having a positive uniaxial property (optically uniaxial)” means that among the values of the refractive indexes nx, ny, and nz in the triaxial directions of an anisotropic element having optical anisotropy. Only two have the same value, indicating that the two refractive indices are smaller than the refractive index of the remaining one axis, and having biaxiality means that the refractive index values nx, ny, nz in the three-axis direction Represent different values.

More specifically, the positive uniaxial rod-like liquid crystalline compound according to the present invention may have a positive or negative dielectric anisotropy, and each may have a dielectric anisotropy in the thickness direction of the optical compensation film. From the viewpoint of ease of tilt control of the optical axis of the liquid crystal molecules in the thickness direction, those having a positive dielectric anisotropy are preferable,
The tilt angle of the optical axis can be adjusted by tilting the liquid crystal molecules themselves having a negative dielectric anisotropy by selecting an alignment layer or the like.

Dielectric anisotropy (Δε) of rod-shaped liquid crystalline compound
Is the difference between the dielectric constant (ε //) when the major axis of the molecule is oriented parallel to the electrolysis and the dielectric constant (ε⊥) when the minor axis of the molecule is oriented parallel to the electrolysis, Δε (= Ε // − ε⊥ ≠
0). The dielectric anisotropy (Δε) affects the anisotropy of the refractive index of light passing through the liquid crystal molecules, and the relationship between the two is Δε = n / −2ε2 (where Δn = n //
-N⊥ = ne-no; ne is the extraordinary light refractive index, no is the ordinary light refractive index, n // is the refractive index for light that is biased in the direction of the orientation vector of the liquid crystal molecule, and n⊥ is the direction perpendicular to the orientation vector. Is the refractive index for light that is biased toward. ).

Note that the values of Δε and Δn are the same as those of a normal T
It is a positive value in the case of a liquid crystal compound used for driving an N liquid crystal cell or the like.

The optical anisotropy (specifically, the anisotropy of the refractive index) of the liquid crystal compound according to the present invention is defined by the whole molecule in the case of a low-molecular liquid crystal compound, In the case of (1), there are a main-chain type liquid crystal and a side-chain type liquid crystal. In any case, the mesogen group is defined according to the low molecular weight liquid crystal compound.

The mesogen group (mesogen unit) described above represents an essential part for imparting liquid crystallinity in a liquid crystal compound. Usually, a mesogen group (mesogen unit) is a rigid part of a core or a flexible part. And a terminal group located at the terminal. However, the above three are not essential as long as the liquid crystal compound exhibits a liquid crystal phase.

Hereinafter, specific examples of the positive uniaxial rod-like liquid crystal compound will be shown, but the present invention is not limited thereto.

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[0114]

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[0115]

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In addition to the specific examples described above, liquid crystal chemistry: Quarterly
Chemical review no. 22, 1994, edited by The Chemical Society of Japan (Society Publishing Center), pp. 42, 44. Further, as the above-mentioned rod-like liquid crystal compound having a positive uniaxial property, an ordinary rod-like nematic liquid crystal used for a TN cell can be suitably used.

As the rod-like liquid crystalline compound according to the present invention, those exhibiting a nematic liquid crystal phase are preferably used.

Specific examples of the biaxial liquid crystal compound include:
For example, Synthetic Organic Chemistry, Vol. 49; No. 5 (1991)
Compounds described on pages 124 to 143 of D.C. W. Bruc
e's research report [AN EU-SPONSORED'O
XFORD WORKSHOP ON BIAXIAL
NEMATICS '(St Benet's Hal
1, University of Oxford 20
-22 December, 1996), p157-2
93]; CHANDRASEK HAR and other research reports [A Thermotropic Biaxial N
eMatic Liquid Crystal; Mol.
Cryst. Liq. Cryst. , 1988, Vo
l. 165, pp. 123-130]; Demu
s, J.S. Goodby et al. [Handbook of
Liquid Crystals Vol. 2B: Low
Molecular Weight Liquid
Crystals II, pp933-943: WIL
EY-VCH, Inc.] and the like.

The liquid crystalline polymer according to the present invention is not particularly limited, but preferably has a positive or negative intrinsic birefringence value. For more information on these, see "LIQUI
DCRYSTALS, 1989, Vol. 5, NO.
1, pp. 159-170 ".

The liquid crystal polymer used in the present invention can be roughly classified into a main chain type and a side chain type as described above, in which mesogen groups are incorporated. It can also be classified into thermotropic and lyotropic.

The liquid crystalline polymer used in the present invention is not particularly limited, but preferably exhibits a nematic liquid crystal. Further, a side chain type is preferable in terms of orientation,
Thermotropic is preferred from the viewpoint of fixing the orientation. The skeleton used in the side chain type liquid crystalline polymer is a vinyl type polymer,
Polysiloxane, polypeptide, polyphosphazene, polyethyleneimine, cellulose and the like are preferred.

In the present invention, the orientation of the liquid crystal compound is determined by the direction in which the optically biaxial cellulose ester film support has the maximum refractive index and the direction in which the rod-shaped liquid crystal compound has the maximum refractive index. Are arranged so as to be substantially perpendicular to the direction projected in the plane of the second transparent support.

In the present invention, "perpendicular" means that the axes are substantially perpendicular to each other as described above, and the angle between the respective axes is within 90 ± 10 °, preferably Within 90 ± 3 °, more preferably within 90 ± 1 °.

Here, the direction in which the refractive index of the rod-shaped liquid crystalline compound becomes maximum usually coincides with the major axis direction of the molecule which is a structural unit of the rod-shaped liquid crystalline compound. However, depending on the substituent of the liquid crystal molecule, the direction of the long axis of the molecule and the direction in which the refractive index has the maximum value may not always coincide. In the present invention, the rod-shaped liquid crystal compound-immobilized layer may be two or more layers.

The axis (not the optical axis) at which the refractive index of the transparent support C having optical biaxiality is the maximum exists in the plane of the transparent support, but the refractive index of the layer made of a liquid crystalline compound is low. The maximum axis does not always exist in the plane of the support. That is, when the liquid crystal compound constituting one layer is, for example, an optically positive uniaxial liquid crystal compound, the axis having the maximum refractive index is the optical axis, and this optical axis forms the transparent support. The angle can take a constant value between 0 ° and 90 °. This is preferably between 5 ° and 8
0 ° or less, more preferably 20 ° or more and 50 ° or less.

Further, as the orientation state with respect to the thickness direction, a so-called hybrid orientation state in which the orientation state is changed continuously or stepwise and distributed within the angle range may be adopted. Are roughly divided into two types.

That is, the axis (the direction indicating the maximum value of the refractive index in the refractive index ellipsoid of the rod-shaped liquid crystalline compound) is
The angle formed by the second transparent support increases from the surface of the second transparent support toward the optically biaxial transparent support C in the thickness direction of the optical compensation film. There are two cases: one is arranged and the other is arranged so as to decrease.

The liquid crystal compound is generally oriented at a certain angle in the vertical direction with respect to the rubbed alignment control plane. At this time, the liquid crystal compound in contact with the alignment control plane and the alignment plane is formed. In the present invention, the pretilt angle, which is an angle, is greater than 0 ° and less than 30 °, and preferably 1 °.
Within 0 °. In this case, the liquid crystalline compound changes continuously from the pretilt angle to 90 °.

The constitutional unit of the rod-shaped liquid crystalline compound can be understood as a unit having an optical axis. For example, it refers to a molecule of the rod-shaped liquid crystalline compound, but is not necessarily limited to a molecular unit. However, when an aggregate of a plurality of molecules has a certain optical axis, the aggregate can also be referred to. Further, an increase or decrease in the angle between the optical compensation film and the optical compensation film means that each of the layers does not have an optical axis as a whole layer. It may change continuously or intermittently in the thickness direction. Such an orientation mode in the thickness direction of the optical compensation film may be hereinafter referred to as hybrid orientation. In this case, as described above, the entire liquid crystal layer does not have an optical axis, but it is possible to define the apparent average tilt angle of the entire layer as an aggregate of liquid crystal units having each optical axis. is there.

This is because the optically anisotropic layer containing the rod-like liquid crystalline compound is refracted by ordinary light and extraordinary light when viewed from the plane including the slow axis of the entire layer and the normal line of the optical compensation film. It can be defined as the angle between the direction in which the rate difference is minimum and the optical compensation film surface.

The apparent average tilt angle of the liquid crystal layer composed of the positive uniaxial liquid crystal compound is more than 0 ° and less than 85 °, preferably 5 ° or more and less than 60 °, more preferably 20 ° or less. Is not less than 50 ° and not more than 50 °.

The fixing of the orientation of the liquid crystalline compound according to the present invention will be described. The liquid crystalline compound according to the present invention is fixed in an aligned state. Further, the structure of the liquid crystal compound according to the present invention is not particularly limited, but the alignment of the liquid crystal compound is performed by a treatment using a chemical reaction or a temperature difference in a state where the liquid crystal molecules are aligned in order to express optical anisotropy. It is required to use it in a fixed state.

When a solution containing a liquid crystal compound is applied,
After the application, the solvent is removed by drying, and a liquid crystal layer having a uniform film thickness can be obtained. The liquid crystal layer can fix the orientation of the liquid crystal by the action of heat or light energy or a chemical reaction using a combination of heat and light energy. In particular, a monomeric liquid crystal compound that is not a high-molecular liquid crystal compound generally has a low viscosity, and the orientation of the liquid crystal is liable to change due to heat externally. It can be fixed by performing a curing reaction by a radical reaction or the like.

In the present invention, when the orientation of the liquid crystal compound is fixed, when an ethylenically unsaturated group is used as the polymerizable group, or when a photopolymerization initiator is used, the activity of the reaction is increased by increasing the activity of the reaction. It is excellent in that the curing time can be shortened. For the generation of radicals, the following light sources can be used. For example, those which can strongly absorb near-ultraviolet rays, such as a high-pressure mercury lamp and a metal halide lamp, are preferably those having a maximum molar extinction coefficient for light of 360 nm to 450 nm of 100 or more, more preferably 500 or more. Electrons, ultraviolet rays, visible rays, and infrared rays (heat rays) can be used as necessary as the light rays as the actinic rays for photopolymerization, but ultraviolet rays are generally preferred. Ultraviolet light sources include low-pressure mercury lamps (germicidal lamps, fluorescent chemical lamps, black lights), high-pressure discharge lamps (high-pressure mercury lamps, metal halide lamps), and short arc discharge lamps (ultra-high-pressure mercury lamps, xenon lamps, mercury-xenon lamps). Can be mentioned.

On the other hand, radical polymerization initiators for the polymerization reaction of ethylenically unsaturated groups include, for example, azobis compounds, peroxides, hydroperoxides, redox catalysts, such as potassium persulfate, ammonium persulfate, and the like.
tert-butyl peroctoate, benzoyl peroxide, isopropyl percarbonate, 2,4-dichlorobenzoyl peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide, dicumyl peroxide, azobisisobutyronitrile, 2,
Examples include 2'-azobis (2-amidinopropane) hydrochloride, benzophenones, acetophenones, benzoins, thioxanthones, and the like. Details of these are described in "Ultraviolet Curing System" General Technology Center, pp. 63-147, 1989. For polymerization of a compound having an epoxy group, as an ultraviolet ray-activated cation catalyst, allyldiazonium salts (hexafluorophosphate, tetrafluoroborate), diallyliodonium salts, group VIa allylonium salts (PF6, AsF6, SbF6) are used. Allylsulfonium salt having an anion) is generally used.

When a curing reaction is carried out by using a radical reaction, irradiation with the above-mentioned actinic ray under a nitrogen atmosphere to avoid a delay in the polymerization reaction due to the presence of oxygen in the air can shorten the reaction time. It is preferable because it can be cured with a small amount of light.

In order to cure the liquid crystal compound by utilizing these reactions, it is necessary to select a monomeric liquid crystal compound which is not a polymer liquid crystal compound having a reactive group introduced therein. is important. This curing reaction can fix the orientation of the liquid crystal.

On the other hand, when the liquid crystalline compound is a polymer liquid crystal, it is not necessary to fix the orientation of the liquid crystal by performing the above-described curing reaction. This is because the polymer liquid crystal compound has a glass transition temperature above the temperature range where the transparent resin substrate is not deteriorated by heat, for example, 90 ° C. or higher. After the installation, the liquid crystal is heated and aligned within the liquid crystal transition temperature range, and then cooled down at a temperature lower than the glass transition temperature, for example, at room temperature, whereby the liquid crystal alignment is maintained.

When the glass transition temperature of the polymer liquid crystal is higher than the heat resistance temperature of the support, the alignment film is provided on the heat resistant support, and the polymer liquid crystal is applied. It can be oriented by heating above the transition temperature. This is allowed to cool to room temperature to fix the orientation of the polymer liquid crystal, and then transferred to the support of the present invention using an adhesive to produce an optically anisotropic body.

The elution block layer used in the present invention will be described. In order to improve the adhesiveness between the second transparent support according to the present invention, in particular, a cellulose ester film and an alignment layer provided on the support, an elution block layer is preferably provided.

The elution block layer refers to a layer of an alignment layer or a liquid crystal compound, which is used as an organic solvent solution when the alignment layer or the liquid crystal compound is coated. This means that elution of any of the compounds constituting the cellulose ester film support into the existing optically anisotropic layer is suppressed. When an alignment layer or a layer of a liquid crystal compound is provided as a thin film, it is a preferable method to prepare and apply an organic solvent solution of these compounds. However, especially a cellulose ester film support such as a cellulose ester film support is composed of a resin and often contains a plasticizer. When an organic solvent dissolving a resin or a plasticizer dissolves a resin or a liquid crystal compound as an alignment layer, diffusion between layers and mixing between layers can be easily inferred by coating.

By providing a resin which is insoluble or hardly soluble in the above-mentioned organic solvent during this time, it is possible to suppress interlayer diffusion and interlayer mixing during the above-mentioned coating. Even if the compound is soluble in an organic solvent that dissolves a resin or a plasticizer, applying an actinic radiation-curable resin on a transparent substrate in the form of a monomer and performing the curing reaction simply involves coating the resin. Unlike this method, a layer having a large number of crosslinked structures can be provided, and when a resin or a liquid crystal compound as an alignment layer is dissolved, diffusion between layers and contamination can be suppressed by coating. Thereby, the orientation of the liquid crystal compound constituting the optically anisotropic layer can be more stably prepared.

Providing the second transparent support according to the present invention, particularly a cellulose ester film, with an elution block layer containing a water-soluble polymer, for example, an organic acid group-containing polymer, can be achieved by combining the cellulose ester film support with the alignment layer. From the viewpoint of improving the adhesiveness, there is a great advantage in terms of production and it is effective.

Examples of the polymer containing an organic acid group include, but are not particularly limited to, a structure having an organic acid group in a side chain of the polymer. Examples of the organic acid group include a -COOH group. Examples of such a compound are not particularly limited, and examples thereof include a structure represented by general formula [1] or general formula [2] described in JP-A-7-333436. The hydrogen of the —COOH group may be substituted with ammonia or an alkali metal cation (sodium cation, lithium cation). Examples of the monomer unit constituting the polymer having an organic acid group include acrylic acid, methacrylic acid, itaconic acid, maleic acid, and fumaric acid. After maleic anhydride is used as a comonomer to increase the molecular weight, the acid anhydride ring may be opened to obtain an organic acid group.

As one mode of the elution block layer according to the present invention, there is an active ray curable resin layer. The actinic ray is preferably an ultraviolet ray because light sources and materials are easily available.

Examples of the ultraviolet curing resin include an ultraviolet curing acrylic urethane resin, an ultraviolet curing polyester acrylate resin, an ultraviolet curing epoxy acrylate resin, an ultraviolet curing polyol acrylate resin, and an ultraviolet curing epoxy resin. Can be mentioned.

The UV-curable acrylic urethane-based resin is
In general, a product obtained by reacting an isocyanate monomer or a prepolymer with a polyester polyol is further added with 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate (hereinafter, only acrylate is shown as including methacrylate). It can be easily obtained by reacting an acrylate monomer having a hydroxyl group such as 2-hydroxypropyl acrylate (see, for example,
-151110).

The UV-curable polyester acrylate resin can be easily obtained by generally reacting a polyester polyol with 2-hydroxyethyl acrylate or 2-hydroxy acrylate monomer (for example, JP-A-59-151112). ).

Specific examples of the ultraviolet-curable epoxy acrylate resin include epoxy acrylate as an oligomer, a reactive diluent and a photoreaction initiator added thereto, and reacted (for example, Kaiping 1
No.-105738). As the photoreaction initiator, one or more of benzoin derivatives, oxime ketone derivatives, benzophenone derivatives, thioxanthone derivatives and the like can be selected and used.

Specific examples of the ultraviolet-curable polyol acrylate resin include trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, and alkyl-modified dipentane. Erythritol pentaacrylate and the like can be mentioned. These resins are usually used together with a known photosensitizer. Further, the above-mentioned photoreaction initiator can also be used as a photosensitizer. Specifically, acetophenone, benzophenone,
Examples thereof include hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone and the like, and derivatives thereof. When an epoxy acrylate photoreactive agent is used, a sensitizer such as n-butylamine, triethylamine, tri-n-butylphosphine and the like can be used. The content of the photoreaction initiator or photosensitizer contained in the ultraviolet-curable resin composition excluding the solvent component volatilized after coating and drying is particularly preferably 0.5 to 5% by mass of the composition.

As a method for applying the coating liquid for the ultraviolet curable resin composition, known methods such as a gravure coater, a spinner coater, a wire bar coater, a roll coater, a reverse coater, an extrusion coater, and an air doctor coater can be used. The film thickness of the actinic ray-curable resin layer containing ultraviolet rays after curing is suitably from 0.05 μm to 30 μm, and preferably from 0.1 to 15 μm. If the dried film thickness is too small, the elution blocking property is reduced, and if the dried film thickness is too large, the optically anisotropic material may curl when it is on the film.

The actinic ray-curable resin has two or more polymerizable groups such as a polymerizable vinyl group, an allyl group, an acryloyl group, a methacryloyl group, an isopropenyl group, and an epoxy group. Those which form a crosslinked structure or a network structure are preferred. Among these active groups, an acryloyl group, a methacryloyl group or an epoxy group is preferred from the viewpoint of polymerization rate and reactivity, and a polyfunctional monomer or oligomer is preferred. For example, UV-curable acrylurethane-based resins, polyester acrylate-based resins, epoxy acrylate-based resins, and polyol acrylate-based resins are preferably used.

Next, the transparent support C having optical biaxiality
Will be described. The transparent support can be attached to an alignment fixing layer of an alignment fixing liquid crystalline compound formed on the transparent support by providing an adhesive layer with a transparent adhesive or an adhesive which is usually used, for example.

The adhesive layer is provided by applying an adhesive composition to a transparent support. Examples of the adhesive of the adhesive composition include an acrylic resin, a urethane resin, a rubber, and a polyvinyl alcohol resin. These resins are used after being dissolved in an organic solvent or as a dispersion dispersed in water. A curing agent may be added to the adhesive composition.

Next, the arrangement of the liquid crystal panel, each optical film, and the optically anisotropic layer in the present invention will be described. In the present invention, the optical film or the optically anisotropic layer disposed on both sides of the liquid crystal cell is a transparent support C having optical biaxiality from the liquid crystal cell side to the outside, and the optically anisotropic layer is at least in this order. It is preferable to arrange them.

R of transparent support C having optical biaxiality
When the ratio of _{t (bi)} / R _{0 (bi)} is greater than 1.4, R _{t (bi)}
It is preferable to arrange a film having a thickness of 60 nm or less, but the arrangement location is preferably outside the transparent support C having optical biaxiality, and more preferably outside the optically anisotropic layer, as viewed from the liquid crystal cell. Further, the in-plane slow axis of the optically anisotropic layer is preferably substantially orthogonal to the in-plane slow axis of the transparent support C having optical biaxiality, and the transparent support having optical biaxiality is preferably used. The in-plane slow axis of C is preferably substantially orthogonal to the rubbing axis of the liquid crystal cell.

That is, the in-plane slow axis of the optically anisotropic layer in which the liquid crystal is aligned and the alignment is fixed is preferably substantially parallel to the rubbing axis of the liquid crystal cell.

In the liquid crystal display device of the present invention, the outer layer portion (viewing angle compensating elliptically polarizing plate) of the liquid crystal cell is prepared as a single viewing angle compensating elliptically polarizing plate in advance, and then the liquid crystal cell is pasted. Good, but it is only necessary that the necessary layer structure exists between the liquid crystal cell and the polarizer in the end.For example, the necessary optical film or optically anisotropic layer is sequentially applied to the liquid crystal cell or the polarizer and pasted. It can also be produced by performing a combination.

The TN type liquid crystal cell of the liquid crystal display device according to the present invention is preferably driven by a TFT and is of a transparent type.
This makes it possible to significantly widen the viewing angle.

[0160]

Hereinafter, the present invention will be described with reference to examples.
The present invention is not limited to these.

Example 1 << Preparation of Dope 1 >> (Composition of Dope 1) Cellulose triacetate synthesized from cotton linter (degree of substitution 2.88) 60 kg Cellulose triacetate synthesized from wood pulp (degree of substitution 2.88) 40 kg Tinuvin 326 (manufactured by Ciba Specialty Chemicals) 0.4 kg Tinuvin 109 (manufactured by Ciba Specialty Chemicals) 0.6 kg Tinuvin 171 (manufactured by Ciba Specialty Chemicals) 0.6 kg Araldide GY260 (manufactured by Asahi Ciba) 15 kg Aerosil R972V (Japan) 0.2 kg Methylene chloride 391 kg Ethanol 34 kg The above composition was charged into a closed container, and completely dissolved under pressure while keeping the temperature at 80 ° C. and stirring. Aerosil 200V
(Manufactured by Nippon Aerosil Co., Ltd.) was mixed and dispersed in advance with a part of ethanol to be added, and this was put into a closed container. This was cooled to a temperature at which it was cast, and then allowed to stand to perform a defoaming operation. Then, the solution was subjected to Azumi Filter Paper No.
Filtration was performed using 244 to prepare dope solution 1.

<< Preparation of Dope Liquid 2 >> (Composition of Dope 2) Cellulose triacetate synthesized from cotton linter (degree of substitution 2.88) 70 kg Cellulose triacetate synthesized from wood pulp (degree of substitution 2.88) 30 kg Tinuvin 326 (Chiba) 0.5 kg Tinuvin 109 (manufactured by Ciba Specialty Chemicals) 1 kg Tinuvin 171 (manufactured by Ciba Specialty Chemicals) 1 kg triphenyl phosphate 8 kg ethylphthalylethyl glycolate 3 kg Aerosil 200V (manufactured by Nippon Aerosil) 2 kg methylene chloride 368 kg ethanol 24.5 kg Dope solution 2 was prepared in the same manner as above except that the composition of dope 1 was changed to the composition of dope 2 described above.

Next, the preparation of the transparent support (cellulose ester film) will be described.
Was used.

<< Preparation of Transparent Support 1 >> Using Dope Solution 1 whose temperature was adjusted to 30 ° C., it was uniformly cast on an endless stainless steel belt (support) heated from the back with hot air at 33 ° C. Immediately after casting, the dope film (web) on the belt was dried by blowing hot air at 25 ° C. After 30 seconds from casting, the belt was heated from the back surface of the belt with hot air at 38 ° C. It was dried by blowing hot air at 55 ° C., peeled 80 seconds after casting, and dried while being conveyed by a number of rolls. The temperature of the endless stainless belt at the peeling portion was 11 ° C. The peeled film is at 50 ° C
After transporting the first drying zone set for 1 minute for 1 minute, 9
The second drying zone set at 0 ° C. is transported for 30 seconds,
Further, it was conveyed in a third drying zone set at 118 ° C. for 15 minutes to perform drying. In the second drying zone, the film was stretched 1.05 times in the width direction by a tenter device. After drying, it was wound up in a roll to obtain a transparent support 1 having a thickness of 40 μm.

A transparent support 2 having a thickness of 40 μm was obtained in the same manner except that the dope 1 used for producing the transparent support 1 was changed to the dope 2. Further, a film thickness of 80 μm
m and a 150 μm-thick transparent support 4 were obtained.

For each of the resulting transparent supports 1 and 2, the retardation (R _t ) in the thickness direction of the transparent support and the retardation (R ₀ ) in the in-plane direction were determined as described below.

R _t R ₀ Film thickness (μm) Transparent support 18 nm 1 nm 40 μm Transparent support 2 31 nm 4 nm 40 μm Transparent support 3 60 nm 5 nm 80 μm Transparent support 4 100 nm 8 nm 150 μm where R ₀ and R _t are as follows: The retardation value of the transparent support defined by the formulas (c) and (d) is shown.

[0168] _{(c) R 0 = (nx} -ny) × d (d) R t = | ((nx + ny) / 2-nz) | in × d formula, nx is the maximum refractive index direction in the plane x direction, n
y is the refractive index in the y direction, which is a direction in a plane perpendicular to the x direction. nz is the refractive index in the thickness direction, and d is the thickness (nm).

Next, a biaxial film was prepared as follows. << Preparation of Transparent Support Having Optical Biaxiality >> (Preparation of Transparent Support 5 Having Optical Biaxiality) A dope having the following composition was prepared.

Cellulose acetate propionate (acetyl substitution degree 2.0, propionyl substitution degree 0.8) 100 kg Tinuvin 326 (manufactured by Ciba Specialty Chemicals Co., Ltd.) 0.4 kg Tinuvin 109 (Ciba Specialty Chemicals Co., Ltd.) 0.4 kg Tinuvin 171 (manufactured by Ciba Specialty Chemicals Co., Ltd.) 0.4 kg Ethylphthalylethyl glycolate 5 kg Triphenyl phosphate 3 kg Methylene chloride 290 kg Ethanol 60 kg Using a dope whose temperature has been adjusted to 30 ° C. , 33 from the back
The mixture was uniformly cast on an endless stainless steel belt (support) heated by hot air at a temperature of ℃. Immediately after casting, hot water at a temperature of 25 ° C. was brought into contact with the back surface of the stainless steel belt and dried for 1 minute on a stainless steel belt whose temperature was controlled. Then, cold water at 15 ° C. was brought into contact with the back surface of the stainless steel belt for 15 minutes. After holding for 2 seconds, it was peeled off from the stainless steel belt. The residual solvent amount in the web at the time of peeling was 100% by mass.

Then, both ends of the peeled web were gripped with clips using a simultaneous biaxial stretching tenter, and the intervals between the clips were simultaneously changed in the width direction and in the casting direction (length direction). The film was stretched 1.35 times and 1.1 times in the casting direction (length direction).

After the completion of the stretching, the film temperature is once set to 80 ° C.
After cooling to 130 ° C using rollers with different peripheral speeds
And stretched 1.1 times in the length direction. Further, the film was dried at 130 ° C. for 10 minutes while being conveyed by rollers to obtain an optically biaxial transparent support 5 having a film thickness of 85 μm. The retardations of the obtained films were respectively R _{0 (bi)} = 50 nm, R _t
(bi) = 120 nm.

(Preparation of Optically Biaxial Transparent Support 6) The web used for producing the optically biaxial transparent support 5 was cast 1.65 times in the width direction at 120 ° C. In the same manner as above, except that the film was stretched 1.1 times in the direction and the film thickness was adjusted to 65 μm, the transparent support 6 having optical biaxiality was formed.
I got The resulting film had R _{0 (bi)} = 70 nm, R
_{t (bi)} = 70 nm.

(Preparation of Optically Biaxial Transparent Support 7) The web used for producing the optically biaxial transparent support 5 was cast 1.5 times in the width direction at 120 ° C. A transparent support 7 having optical biaxiality was obtained in the same manner as described above except that the film was stretched 1.1 times in the direction and the film thickness was adjusted to 85 μm. The resulting film has R _{0 (bi)} = 70 nm, R _{t (bi)}
= 105 nm.

<< Preparation of Polarizing Plate >> (Preparation of Viewing Angle Compensating Elliptically Polarizing Plate A)
It was immersed in a 2 mol / l aqueous solution of sodium hydroxide at 0 ° C. for 2 minutes, washed with water, and dried at 100 ° C. for 10 minutes to obtain an alkali-saponified transparent support (cellulose ester film).

Further, a polyvinyl alcohol film having a thickness of 120 μm was immersed in 100 parts by mass of an aqueous solution containing 1 part by mass of iodine and 4 parts by mass of boric acid and stretched 4 times at 50 ° C. to form a polarizing film (polarizer 1). Had made.

The polarizer 1 was prepared by laminating a transparent support 3 (cellulose ester film) on one surface of the polarizer 1 which had been alkali-saponified, using a 5% aqueous solution of completely saponified polyvinyl alcohol as an adhesive.

Subsequently, a gelatin thin film (0.1 μm) was coated on the polarizing plate 1, and an alkyl-modified polyvinyl alcohol having the structure shown below was mixed with methanol / water = 1: 1.
3 was applied with a wire bar # 3.
After drying this with hot air at 65 ° C., in the plane of the support, the rubbing treatment is performed on the alkyl-modified polyvinyl alcohol-coated surface in a direction parallel to the absorption axis of the polarizing plate,
An alignment layer was formed. These are referred to as a polarizing plate 1a.

[0179]

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The following solution LC-1 was applied on the polarizing plate 1a produced above using a wire bar # 6. Furthermore, this was dried in a windless state at 55 ° C. for 30 seconds, and then at 100 ° C.
After performing a heat treatment for 30 seconds, the temperature was gradually lowered, and after purging with nitrogen at 98 kPa for 60 seconds, a film was cured with ultraviolet light of 450 mJ / cm ² under the condition of an oxygen concentration of 0.1%. Thus, a polarizing plate 1b having one optically anisotropic layer in which the orientation of the liquid crystal compound was fixed was obtained.

Further, the polarizing plate 1b obtained above and the transparent optically biaxial support 6 were bonded together using SK Dyne 2092 (manufactured by Soken Chemical Co., Ltd.) as an adhesive. At the time of bonding, the optically anisotropic layer of the polarizing plate 1b was adjusted so that the slow axis in the film plane of the transparent support 6 having optical biaxiality coincided with the viewing angle compensating elliptically polarizing plate A. I got

(Preparation of Viewing Angle Compensated Elliptically Polarizing Plate B) A gelatin thin film (0.1 μm) was coated on the transparent support 1, and the above-mentioned alkyl-modified polyvinyl alcohol was dissolved in methanol / water = 1: 3. A 5% solution was applied by wire bar # 3. After drying with hot air at 65 ° C., rubbing treatment was performed on the surface of the transparent support 1 on which the alkyl-modified polyvinyl alcohol was applied to form an alignment layer, and then the following solution LC-1 was formed thereon. Was applied using a wire bar # 6. Further, this was dried in a windless state at 55 ° C. for 30 seconds, then subjected to a heat treatment at 100 ° C. for 30 seconds, gradually cooled, purged with nitrogen at 98 kPa for 60 seconds, and 450 mJ under an oxygen concentration of 0.1%. / Cm ² , a film cured by ultraviolet light was produced, and a transparent support 1 having an optically anisotropic layer was produced.

Subsequently, the transparent support 1 having the optically anisotropic layer described above was saponified in the same manner as in the preparation of the viewing angle compensating elliptically polarizing plate A, and a completely saponified polyvinyl alcohol 5% aqueous solution was used as an adhesive. , Like sandwiching a polarizer,
A polarizing plate 1c having an optically anisotropic layer bonded to a separately prepared transparent support 1 (saponified) was produced.

Further, the polarizing plate 1c obtained above and the transparent support 5 having optical biaxiality were bonded together using SK Dyne 2092 (manufactured by Soken Chemical Co., Ltd.) as an adhesive. At the time of bonding, the optically anisotropic layer of the polarizing plate 1c is adjusted so that the slow axis in the film plane of the optically biaxially transparent support 6 is aligned with the optically anisotropic layer. I got

(Preparation of Viewing Angle Compensated Elliptically Polarizing Plate C) A gelatin thin film (0.1 μm) was coated on the transparent support 3 and the above-mentioned alkyl-modified polyvinyl alcohol was dissolved in methanol / water = 1: 3. A 5% solution was applied by wire bar # 3. After drying with hot air at 65 ° C., rubbing treatment was performed on the surface of the transparent support 1 on which the alkyl-modified polyvinyl alcohol was applied to form an alignment layer, and then the following solution LC-1 was formed thereon. Was applied using a wire bar # 6. Further, this was dried in a windless state at 55 ° C. for 30 seconds, then subjected to a heat treatment at 100 ° C. for 30 seconds, gradually cooled, purged with nitrogen at 98 kPa for 60 seconds, and 450 mJ under an oxygen concentration of 0.1%. / Cm ² was prepared by curing with ultraviolet rays.

Subsequently, a saponification treatment is performed in the same manner as in the production of the viewing angle compensating elliptically polarizing plate A, and a completely saponified polyvinyl alcohol 5% aqueous solution is used as an adhesive to bond the polarizer to the optically anisotropic layer. A polarizing plate 1d was produced.

Further, the polarizing plate 1d obtained above and the optically biaxially transparent support 7 were bonded together using SK Dyne 2092 (manufactured by Soken Chemical Co., Ltd.) as an adhesive. At the time of bonding, the optically anisotropic layer of the polarizing plate 1d is adjusted so that the slow axis in the film plane of the optically biaxially transparent support 7 coincides with the optically anisotropic layer. I got

(Preparation of Viewing Angle Compensating Elliptically Polarizing Plate D) A viewing angle compensating elliptically polarizing plate was prepared in the same manner as the production of the viewing angle compensating elliptically polarizing plate B, except that the transparent support 2 was used instead of the transparent support 1. D was prepared.

(Preparation of Viewing Angle Compensating Elliptically Polarizing Plate E) A viewing angle compensating elliptically polarizing plate was prepared in the same manner as the production of the viewing angle compensating elliptically polarizing plate B, except that the transparent support 3 was used instead of the transparent support 1. E was produced.

(Preparation of Viewing Angle Compensating Elliptically Polarizing Plate F) A viewing angle compensating elliptically polarizing plate was produced in the same manner as the production of the viewing angle compensating elliptically polarizing plate C, except that the transparent support 4 was used instead of the transparent support 3. F was produced.

(Composition of Solution LC-1) MEK 86 parts Compound 2 3 parts Compound 3 2 parts Compound 4 3 parts Compound 5 3 parts Irgacure 369 (manufactured by Ciba Specialty Chemicals) 1 part

[0192]

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[0193]

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[0194]

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[0195]

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Each of the cured layers of the layer containing the liquid crystalline compound was an optically anisotropic layer having a thickness of 1.4 μm. The average tilt angle of these films was measured using Kojira manufactured by Oji Scientific. In addition, the tilt angle (pretilt angle) near the alignment film was measured using a crystal rotation method, and the tilt angle (pretilt angle) was measured in the optically anisotropic layer in which the orientation of the liquid crystal of the viewing angle compensation elliptically polarizing plates A to F was fixed. The pretilt angle was 2 ° and the average tilt angle was 34 °.

<< Preparation of Comparative Viewing Angle Compensating Elliptically Polarizing Plate G >>
Gelatin undercoating was performed on the transparent support 6 having optical biaxiality, and the above-mentioned alkyl-modified polyvinyl alcohol solution was applied, followed by drying and rubbing in the same manner. The rubbing direction was perpendicular to the in-plane slow axis direction of the optically biaxial transparent support 6.

Further, the solution LC-1 described above was similarly applied, dried, heat-treated and cured by ultraviolet rays to obtain a film having an optically anisotropic layer in which the orientation of liquid crystal was fixed. Subsequently, using SK Dyne 2092 (manufactured by Soken Chemical Co., Ltd.) as an adhesive, the optically anisotropic layer side of this film was bonded to the transparent support of the polarizing plate 1 described above. G
I got The bonding direction was such that the in-plane slow axis of the transparent support 6 having optical biaxiality coincided with the transmission axis of the polarizing plate 1.

The pretilt angle was 2 ° and the average tilt angle was 34 ° as measured on the optically anisotropic layer of the viewing angle compensating elliptically polarizing plate G prepared above in which the liquid crystal direction was fixed.

In the optically anisotropic layers of the viewing angle compensating elliptically polarizing plates A to F of the present invention, the optically anisotropic compound molecules (after the liquid crystal compound is oriented in a specific direction, The angle (the so-called pretilt angle) between the transparent support surface and the transparent support surface is small, and the optically anisotropic compound molecules become closer to the interface portion of the optically biaxial transparent support. Oriented so that the angle between the transparent support surface having optically biaxiality increases,
And it is fixed.

In the optical anisotropic layer of the comparative viewing angle compensating elliptically polarizing plate G, contrary to the above, at the interface portion on the transparent support side, the optically anisotropic compound molecules (the liquid crystal compound is oriented in a specific direction) After that, the angle between the transparent support surface and the surface where the orientation is fixed) is large, and the optically anisotropic compound molecules become optically closer to the interface portion of the optically biaxial transparent support. It is oriented and fixed so that the angle with the transparent support surface having biaxiality is reduced.

<< Evaluation of Viewing Angle Compensating Elliptically Polarizing Plate >> Viewing angle compensating elliptically polarizing plates A to F of the present invention obtained above, comparative viewing angle compensating elliptically polarizing plate G, and polarizing plate 1 (polarizing plate) described above The optical compensatory film and the polarizing plate, which were previously bonded to each other, were peeled off from the NEC 15 inch display Multi Sync LCD 1525J, and the viewing angle compensating elliptically polarizing plates A to F of the present invention were compared. The compensating elliptically polarizing plate G and the comparative polarizing plate 1 were bonded so that their absorption axes were in the same direction as the absorption axis of the polarizing plate previously bonded.

The viewing angle was evaluated by using the viewing angle compensating elliptically polarizing plates A to F of the present invention obtained above, the comparative viewing angle compensating elliptically polarizing plate G, and the polarizing plate 1 described above. ) Is bonded to EZ-c manufactured by ELDIM.
The viewing angle was measured using ontrast. As the evaluation of the viewing angle, the contrast ratio between the white display and the black display of the liquid crystal panel was 10 or more, and the range of the inclination angle from the normal direction to the panel surface indicating the region where the inversion occurred was expressed.

Table 1 shows the obtained results.

[0205]

[Table 1]

From Table 1, it is clear that the sample of the present invention shows better numerical values in both the contrast ratio and the inversion region as compared with the comparative sample, and shows extremely high viewing angle improvement characteristics.

[0207]

According to the present invention, a TN-TFT
Angle Compensation Elliptically Polarizing Plate that Can Easily Improve the Viewing Angle Characteristics of a Type LCD, That is, Coloring of the Screen When Obliquely Viewed, and Inversion of Brightness and Darkness, and an Optical Compensation Sheet Using the Same And a liquid crystal display device in which the viewing angle is remarkably improved with a simple structure can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus for producing a transparent support according to the present invention.

FIG. 2 is a schematic cross-sectional view showing one step of a method for manufacturing a viewing angle compensating elliptically polarizing plate of the present invention.

FIG. 3 is a schematic cross-sectional view showing one step of a method for manufacturing a viewing angle compensating elliptically polarizing plate of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Endless stainless belt 2 Die 3 Low-temperature drying zone 4 High-temperature drying zone 5 Casting part 6 Peeling part 7 Peeling roll 8 First drying zone 9 Conveyance roll 13 Second drying zone 11 Third drying zone 12 Winding part A Polarizing plate B Viewing angle compensating elliptically polarizing plates 21a, 21b Transparent support 22 Polarizer 23 Optically anisotropic layer 24 Optically biaxial transparent support C 10 Liquid crystal compound

Continuing on the front page (72) Inventor Koji Tasaka 1st Konica Corporation, Sakura-cho, Hino-shi, Tokyo In-house (72) Inventor Takatoshi Yajima 1st Konica Corporation, Sakura-cho, Hino-shi, Tokyo In-house (72) Inventor Kenichiro Fujika Tokyo In-house (72) Inventor Toshiaki Shibue, Sakura-cho, Hino-shi, Tokyo In-house (72) Inventor F-term (reference) 2H049 BA04 BA06 BA25 BA27 BA42 BB43 BB49 BC03 BC04 BC22 2H091 FA08X FA08Z FA11X FA11Z FC09 JA10 LA30

Claims (21)

[Claims] 1. A viewing angle compensated elliptically polarized light having a polarizing plate A, an optically anisotropic layer formed by orienting and fixing a liquid crystalline compound in a specific direction, and a transparent support C having optical biaxiality. A viewing angle-compensating elliptically polarizing plate, which is manufactured through the following steps (1) and (2). (1) The optically anisotropic layer is formed directly on the polarizing plate A or via another transparent support, and then (2) directly or via another layer on the optically anisotropic layer. The transparent support C having optical biaxiality is provided. 2. A first transparent support, a polarizer, a second transparent support, an optically anisotropic layer formed by fixing the orientation of a liquid crystalline compound, and a transparent support C having optical biaxiality. And in this order, the viewing angle compensating elliptically polarizing plate comprises the following steps (1), (2) and (3):
A viewing angle compensating elliptically polarizing plate, which is manufactured through the following. (1) Directly aligning and fixing a liquid crystalline compound on the second transparent support or via the third transparent support to form an optically anisotropic layer; (2) Second transparent support The side of the body where the optically anisotropic layer is not coated and the first transparent support are arranged so as to sandwich a polarizer; and (3) on the optically anisotropic layer, directly or otherwise. The transparent support C having optical biaxiality is provided through the layer of. 3. A first transparent support, a polarizer, a second transparent support, an optically anisotropic layer formed by fixing the orientation of a liquid crystalline compound, and a transparent support C having optical biaxiality. And in this order, the viewing angle compensating elliptically polarizing plate comprises the following steps (1), (2) and (3):
A viewing angle compensating elliptically polarizing plate, which is manufactured through the following. (1) aligning and fixing a liquid crystal compound directly on the second transparent support or via the third transparent support to form an optically anisotropic layer; (2) the optically anisotropic layer A transparent support C having optical biaxiality is provided directly or via another layer, and (3) a side of the second transparent support on which the optically anisotropic layer is not provided, and Are disposed so as to face each other and sandwich the polarizer. 4. R of the transparent support C having optical biaxiality
If _{t (bi)} / R 0 _{of (bi)} value exceeds 1.4, any one of claims 1 to 3 R _t value of the second transparent substrate is equal to or is 60nm or less 4. The viewing angle-compensated elliptically polarizing plate according to 1. 5. R of the transparent support C having optical biaxiality
If _{t (bi)} / R 0 _{of (bi)} value exceeds 2.0, any one of claims 1 to 3 R _t value of the second transparent substrate is equal to or is 35nm or less 4. The viewing angle-compensated elliptically polarizing plate according to 1. 6. The viewing angle-compensated elliptically polarized light according to claim 1, wherein the optically biaxial transparent support C has an R ₀ value of 20 nm to 95 nm. Board. 7. The viewing angle compensated elliptically polarized light according to claim 1, wherein the optically biaxially transparent support C has an R ₀ value of 45 nm to 75 nm. Board. 8. A viewing angle compensated elliptically polarized light having a polarizing plate A, an optically anisotropic layer formed by orienting and fixing a liquid crystalline compound in a specific direction, and a transparent support C having optical biaxiality. In the plate manufacturing method, the following steps (1) and (2)
A method for producing a viewing angle compensating elliptically polarizing plate, comprising: (1) The optically anisotropic layer is formed directly on the polarizing plate A or via another transparent support, and then (2) the optically biaxial transparent film is formed on the optically anisotropic layer. A support C is provided. 9. A first transparent support, a polarizer, a second transparent support, an optically anisotropic layer formed by fixing the orientation of a liquid crystalline compound, and a transparent support C having optical biaxiality. And a manufacturing method of a viewing angle compensating elliptically polarizing plate, which is manufactured through the following steps (1), (2) and (3). . (1) Directly aligning and fixing a liquid crystalline compound on the second transparent support or via the third transparent support to form an optically anisotropic layer; (2) Second transparent support The side of the body where the optically anisotropic layer is not coated and the first transparent support are arranged so as to sandwich a polarizer; and (3) on the optically anisotropic layer, directly or otherwise. The transparent support C having optical biaxiality is provided through the layer of. 10. A first transparent support, a polarizer, a second transparent support, an optically anisotropic layer formed by fixing the orientation of a liquid crystalline compound, and a transparent support C having optical biaxiality. And a manufacturing method of a viewing angle compensating elliptically polarizing plate, which is manufactured through the following steps (1), (2) and (3). . (1) aligning and fixing a liquid crystal compound directly on the second transparent support or via the third transparent support to form an optically anisotropic layer; (2) the optically anisotropic layer A transparent support C having optical biaxiality is provided directly or via another layer, and (3) a side of the second transparent support on which the optically anisotropic layer is not provided, and Are disposed so as to face each other and sandwich the polarizer. 11. In the case of a transparent support C having an optical biaxial property R _{t (bi)} / R 0 _{of (bi)} value exceeds 1.4, R _t value of the second transparent support 60nm The method for producing a viewing angle compensation elliptically polarizing plate according to any one of claims 8 to 10, wherein: When 12. the transparent support C having an optical biaxial property R _{t (bi)} / R 0 _{of (bi)} value exceeds 2.0, R _t value of the second transparent support 35nm The method for producing a viewing angle compensation elliptically polarizing plate according to any one of claims 8 to 10, wherein: 13. A transparent support C having optical biaxiality.
13. The method for producing a viewing angle compensating elliptically polarizing plate according to any one of claims 8 to 12, wherein the R ₀ value is from 20 nm to 95 nm. 14. A transparent support C having optically biaxial properties.
13. The method for producing a viewing-angle-compensating elliptically polarizing plate according to claim 8, wherein the R ₀ value is from 45 nm to 75 nm. 15. A liquid crystal display comprising the viewing angle compensating elliptically polarizing plate according to claim 1. Description: 16. An optically biaxially transparent support C, an optically anisotropic layer formed by orienting and fixing a liquid crystalline compound, and a polarizer on both sides of a liquid crystal cell in this order. Liquid crystal display device. 17. A transparent support C having optically biaxial properties, an optically anisotropic layer formed by aligning and fixing a liquid crystal compound, a second transparent support, and a polarizer on both sides of a liquid crystal cell. ,
_{Rt (bi)} / _{R0 (bi) of the} transparent support C having the first transparent support in this order, and having the optically biaxial property.
If the value exceeds 1.4, the liquid crystal display device which R _t value of the second transparent substrate is equal to or is 60nm or less. 18. A transparent support C having an optically biaxial property on both sides of a liquid crystal cell, an optically anisotropic layer formed by aligning and fixing a liquid crystalline compound, a second transparent support, and a polarizer. ,
_{Rt (bi)} / _{R0 (bi) of the} optically biaxial transparent support C having the first transparent support in this order.
If the value exceeds 2.0, the liquid crystal display device which R _t value of the second transparent substrate is equal to or is 35nm or less. 19. The method according to claim 15, wherein the second transparent support is disposed between the optically anisotropic layer and the polarizer.
19. The liquid crystal display device according to any one of 18. 20. An optically biaxial transparent support C
The liquid crystal display device according to any one of claims 15 to 19, wherein the R0 _(bi) value of the liquid crystal is 20 nm to 95 nm. 21. Optically biaxially transparent support C
20. The liquid crystal display device according to claim 15, wherein the R0 _(bi) value of the liquid crystal is 45 nm to 75 nm.