Vertically-aligned (VA) liquid crystal display device

Abstract

A vertical alignment mode liquid crystal display device having an improved viewing angle characteristic is disclosed. The liquid crystal display device uses a liquid crystal having a negative anisotropic dielectric constant, and orientations of the liquid crystal are vertical to substrates when no voltage is applied, almost horizontal when a predetermined voltage is applied, and oblique when an intermediate voltage is applied. At least one of the substrates includes a structure as domain regulating means, and inclined surfaces of the structure operate to regulate azimuths of the oblique orientations of the liquid crystal when the intermediate voltage is applied.

Description

This is a divisional of application Ser. No. 09/097,027, filed Jun. 12, 1998 S

FIG. 217 is a diagram showing the constitution of a liquid crystal display device which is a 52th embodiment of the present invention.

Color filter and a common electrode (namely, what is called a full-surface covering electrode) are formed on the liquid-crystal-side surface of CF (Color Filter) substrate that is one of substrates 91 and 92. Further, TFT elements, bus lines and pixel electrodes are formed on the liquid-crystal-side surface of TFT substrate that is the other of the substrates 91 and 92.

Vertical alignment film is formed on the liquid-crystal-side surfaces of the substrates 91 and 92 by applying a vertical alignment material thereto through transfer printing, and by then burn the material at 180° C. Subsequently, a positive photosensitive overcoating (or protecting) material is applied onto the vertical alignment film through spin coating. Then, a protrusion pattern shown in FIG. 54 is formed by performing prebaking, exposure and postbaking.

The substrates 91 and 92 are bonded together through a spacer having a diameter of 3.5 μm. Further, a space formed therebetween is sealed with a liquid crystal material having negative dielectric constant anisotropy. Thus a liquid crystal panel is completed.

As illustrated in FIG. 217, the liquid crystal display device, which is the 52th embodiment of the present invention, is constituted by placing a first polarizing plate 11, a first positive uniaxial film 94, two substrates 91 and 92, a second positive uniaxial film 94 and a second polarizing plate 15 therein in this order. Incidentally, the first and second uniaxial films 94 are placed so that the phase lag axis of the first positive uniaxial film 94 intersects with the absorption axis of the first polarizing plate 11 at right angles.

FIG. 218 shows iso-contrast curves in the case that each of the phase differences R₀ and R₁ respectively corresponding to the first and second positive uniaxial films 61 of the 52th embodiment is set at 110 nm. Further, FIG. 219 shows viewing angle regions, in each of which gray-scale inversion occurs during an eight-gray-scale-level driving operation in such a case. As is apparent from the comparison with FIGS. 214 and 215, a range, in which high contrast is obtained, is enlarged extensively, with the result that the gray-scale reversal does not occur in the entire viewing angle region. Consequently, the viewing angle characteristics are considerably improved.

Incidentally, the viewing angle characteristics were studied by changing the retardation R₀ and R₁ in various ways in the case of the constitution of FIG. 217. Process of studying the viewing angle was as follows. First, while changing the phase differences R₀ and R₁, an angle at which the contrast (ratio) was 10, was found in each of an upper right direction (corresponding to an azimuth angle of 45° towards the right top), an upper left direction (corresponding to an azimuth angle of 135° towards the left top), a lower left direction (corresponding to an azimuth angle of 225° towards the left bottom) and a lower right direction (corresponding to an azimuth angle of 315° towards the right bottom) with respect to the liquid crystal panel, as viewed in this figure. FIG. 220 is a contour graph showing each contour that connects points, each of which is represented by coordinates R₀ and R₁ thereof and corresponds to the found angle having a same value. Incidentally, the contour graphs respectively corresponding to the upper right direction, the upper left direction, the lower left direction and the lower right direction were the same with one another. It is considered that this was because four regions obtained by the alignment division were equivalent to one another as a result of using the protrusion pattern shown in FIG. 54.

In the case of FIG. 217, the angle, at which the contrast ratio is 10 in each of the directions respectively corresponding to the azimuth angles 45°, 135°, 225° and 315°, is 39°. This reveals that the use of the optical retardation film is effective in the case of the combination of the coordinates R₀ and R₁ shown in FIG. 223. Incidentally, in the case illustrated in FIG. 223, the angle, at which the contrast ratio is 10, is not less than 39° when R₀ and R₁ meet the following conditions or requirements:
R₁≦450 nm−R₀, R₀−250 nm≦R₁≦R₀+250 nm, 0≦R₀ and 0≦R₁.

Additionally, the retardation Δn·d caused in a liquid crystal was changed within a piratical range. Moreover, the twist angle was changed within a range of 0 to 90°. Similarly, the optimum conditions for R₀ and R₁ were obtained. As a result, it was ascertained that the optimum conditions were the same as the aforementioned requirements even in such cases.

FIG. 221 is a diagram showing the constitution of a liquid crystal display device which is a 53rd embodiment of the present invention. This embodiment is different from the 52nd embodiment in that two positive uniaxial films, namely, first and second positive uniaxial films 94 are placed between the first polarizing plate 11 and the liquid crystal panel, that the phase lag axes of the two positive uniaxial films 94 intersect with each other at right angles and that the phase lag axis of the second positive uniaxial film adjoining the first polarizing plate 11 intersects with the absorption axis of the first polarizing plate 11 at right angles.

FIG. 222 shows iso-contrast curves in the case that the phase differences R₀ and R₁ respectively corresponding to the first and second positive uniaxial films 61 of the 52nd embodiment are set at 110 nm and 270 nm, respectively. Further, FIG. 223 shows viewing angle regions, in each of which gray-scale inversion occurs during an eight-gray-scale-level driving operation in such a case. As is obvious from the comparison with FIGS. 214 and 215, a range, in which high contrast is obtained, is enlarged extensively. Moreover, the range, in which the gray-scale reversal occurs, is greatly reduced. Consequently, the viewing angle characteristics are considerably improved.

FIG. 224 shows the viewing angle characteristics obtained as a result of being studied by changing the phase differences R₀ and R₁ of the first and second uniaxial films 94 in various ways in the case of the constitution of FIG. 221, similarly as in the case of the 52th embodiment. The viewing angle characteristics shown in FIG. 224 are the same as of FIG. 220 and are illustrated by a contour graph showing angles, at which the contrast ratio is 10, in terms of coordinates R₀ and R₁. As is seen therefrom, the angle, at which the contrast ratio is 10, is not less than 39° when R₀ and R₁ meet the following conditions or requirements:
2R₀−170 nm≦R₁≦2R₀+280 nm, R₁≦−R₀/2+800 nm, 0≦R₀ and 0≦R₁.

Further, it was ascertained that the optimum conditions were the same as the aforementioned requirements even in the cases where, similarly, in the case of the 53th embodiment, the retardation Δn·d caused in a liquid crystal was changed within a practical range and where, moreover, the twist angle was changed within a range of 0 to 90°.

FIG. 225 is a diagram showing the constitution of a liquid crystal display device which is a 54th embodiment of the present invention.

This embodiment is different from the 52th embodiment in that the first negative uniaxial film 95 is placed between the liquid crystal panel and the first polarizing plate 11 and that the second negative uniaxial film 95 is placed between the liquid crystal panel and the second polarizing plate 15.

FIG. 226 shows the viewing angle characteristics obtained as a result of being studied by changing the phase differences R₀ and R₁ in various ways in the case of the constitution of FIG. 225, similarly as in the case of the 52th embodiment. The viewing angle characteristics shown in FIG. 226 are the same as of FIG. 220 and are illustrated by a contour graph showing angles, at which the contrast ratio is 10, in terms of coordinates R₀ and R₁. As is seen therefrom, the angle, at which the contrast ratio is 10, is not less than 39° when R₀ and R₁ meet the following condition or requirement:
R₀+R₁≦500 nm.

Incidentally, similarly, in the case of the 54th embodiment, the retardation Δn·d caused in a liquid crystal and the upper limit to the optimum condition were studied by changing the retardation Δn·d within a practical range. FIG. 227 illustrate results of this study. Let R_LC denote Δn·d caused in the liquid crystal. Consequently, the optimum value in the optimum condition for a sum of the phase differences respectively corresponding to the phase difference films is not more than (1.7×R_LC+50) nm.

Further, although this characteristic condition relates to the contrast (ratio), the optimum condition for the gray-scale reversal was similarly studied. Angles, at which gray-scale reversal occurs, were found by changing the phase differences R₀ and R₁ in the direction of the thickness of the first and second negative uniaxial films 95 in various manners in the constitution of FIG. 225, similarly as in the case of the contrast ratio. FIG. 228 shows contour graphs obtained from the found angles, which is illustrated by using the coordinates R₀ and R₁. Incidentally, the angle, at which the gray-scale reversal occurs in the case illustrated in FIG. 215, is 52°. Thus, when the phase differences R₀ and R₁ have values at which the angle enabling an occurrence of the gray-scale reversal is not less than 52° in the case illustrated in FIG. 228, the phase difference film has an effect on the gray-scale reversal. In the case shown in FIG. 228, the angle, at which the contrast ratio is 10, is not less than 39° when R₀ and R₁ meet the following condition or requirement:
R₀+R₁≦345 nm.

Then, in the case of the 54th embodiment, the relation between Δn·d caused in a liquid crystal (display) cell and the upper limit to the optimum condition was studied by changing the retardation Δn·d within a practical range. FIG. 229 illustrate results of this study. This reveals that the upper limit to the optimal condition is nearly constant independent of Δn·d caused in the liquid crystal cell and that the optimum condition for a sum of the phase differences respectively corresponding to the phase difference films is not more than 350 nm.

It is desirable that the angle, at which the contrast ratio is not less than 50°. Further, in view of the gray-scale reversal and Δn·d caused in the liquid crystal cell, it is preferable that a sum of the phase differences respectively corresponding to the phase difference films is not less than 30 nm but is not more than 270 nm.

Moreover, as a result of studying the optimal condition by changing the twist angle in a range of 0 to 90°, it is found that the optimum condition was the same as the aforementioned requirement.

A 55th embodiment of the present invention is obtained by removing one of the first and second negative uniaxial films 95 from the constitution of the liquid crystal display device of FIG. 225, which is the third embodiment of the present invention.

FIG. 230 shows iso-contrast curves in the case that the phase difference corresponding to one of the negative uniaxial films 95 of the 55th embodiment is set at 200 nm. Further, FIG. 231 shows viewing angle regions, in each of which gray-scale inversion occurs during an eight-gray-scale-level driving operation in such a case. As is obvious from the comparison with FIGS. 214 and 215, a range, in which high contrast is obtained, is enlarged extensively. Moreover, the range, in which the gray-scale reversal occurs, is greatly reduced. Consequently, the viewing angle characteristics are considerably improved. Moreover, the optimal condition for realizing the contrast ratio of 10 and the optimal condition for the gray-scale reversal were studied. Results of this study reveal that it is sufficient to use a single negative uniaxial film having the phase difference corresponding to a sum of the phase differences of the negative uniaxial films of the 54th embodiment.

Each of 56th to 58th embodiments of the present invention uses the combination of positive and negative uniaxial films. Although there are various kinds of modifications to the arrangement of such films, it has been found that the constitutions of the fifth to seventh embodiments have (advantageous) effects.

FIG. 232 is a diagram showing the constitution of a liquid crystal display device which is a 56th embodiment of the present invention.

The 56th embodiment differs from the 52th embodiment in that a negative uniaxial film 95 is used and placed between the liquid crystal panel and the first polarizing plate 11 instead of the first positive uniaxial film 94.

FIG. 233 shows iso-contrast curves in the case that the phase difference R₀ in an inplane direction in the surface of the positive uniaxial film 94 and the phase difference R₁ in the direction of thickness of the negative uniaxial film 95 are set at 150 nm in the 56th embodiment. Further, FIG. 234 shows viewing angle regions, in each of which gray-scale inversion occurs during an eight-gray-scale-level driving operation in such a case. As is obvious from the comparison with FIGS. 214 and 215, a range, in which high contrast is obtained, is enlarged extensively. Moreover, the range, in which the gray-scale reversal occurs, is greatly reduced. Consequently, the viewing angle characteristics are considerably improved.

In the case of the 56th embodiment, the optimal condition for the contrast was studied. FIG. 235 shows results of this study, which reveal that the optimum condition indicated by FIG. 235 was the same as illustrated in FIG. 220.

FIG. 236 is a diagram showing the constitution of a liquid crystal display device which is a 57th embodiment of the present invention. This embodiment is different from the 52th embodiment in that a positive uniaxial films 61 are placed between the liquid crystal panel and the first polarizing plate 11 and that a negative uniaxial film 95 is placed between this positive uniaxial film 94 and the first polarizing plate 11. The positive uniaxial film 94 is placed in such a manner that the phase lag axis thereof intersects with the absorption axis of the first polarizing plate 11 at right angles.

FIG. 237 shows iso-contrast curves in the case that the phase difference R₀ in an inplane direction in the surface of the positive uniaxial film 61 and the phase difference R₁ in the direction of thickness of the negative uniaxial film 62 are set at 50 nm and 150 nm in the 57th embodiment, respectively. Further, FIG. 238 shows viewing angle regions, in each of which gray-scale inversion occurs during an eight-gray-scale-level driving operation in such a case. As is obvious from the comparison with FIGS. 214 and 215, a range, in which high contrast is obtained, is enlarged extensively. Moreover, the range, in which the gray-scale reversal occurs, is greatly reduced. Consequently, the viewing angle characteristics are considerably improved.

Even in the case of the 57th embodiment, the optimal condition for the contrast was studied. FIG. 239 shows results of this study, which reveal that the optimum condition indicated by FIG. 239 was the same as illustrated in FIG. 220.

FIG. 240 is a diagram showing the constitution of a liquid crystal display device which is a 58th embodiment of the present invention. This embodiment is different from the 52th embodiment in that a negative uniaxial films 95 are placed between the liquid crystal panel and the first polarizing plate 11 and that a positive uniaxial film 94 is placed between this negative uniaxial film 95 and the first polarizing plate 11. The positive uniaxial film 94 is placed in such a manner that the phase lag axis thereof intersects with the absorption axis of the first polarizing plate 11 at right angles.

FIG. 241 shows iso-contrast curves in the case that the phase difference R₁ in an inplane direction in the surface of the positive uniaxial film 94 and the phase difference R₀ in the direction of thickness of the negative uniaxial film 95 are set at 150 nm in the 58th embodiment. Further, FIG. 242 shows viewing angle regions, in each of which gray-scale inversion occurs during an eight-gray-scale-level driving operation in such a case. As is obvious from the comparison with FIGS. 214 and 215, a range, in which high contrast is obtained, is enlarged extensively. Moreover, the range, in which the gray-scale reversal occurs, is greatly reduced. Consequently, the viewing angle characteristics are considerably improved.

Even in the case of the 58th embodiment, the optimal condition for the contrast was studied. FIG. 243 shows results of this study, which reveal that the optimum condition indicated by FIG. 243 was the same as illustrated in FIG. 220.

FIG. 244 is a diagram showing the constitution of a liquid crystal display device which is an 59th embodiment of the present invention.

This embodiment is different from the 52nd embodiment in that a phase difference film 96, whose inplane dielectric constantes n_x and n_y and dielectric constant n_z in the direction of thickness thereof have the following relation: n_x, n_y≧n_z, is placed between the liquid crystal panel and the first polarizing plate 11 and that a positive uniaxial film 94 is removed from between the liquid crystal panel and the second polarizing plate 15. The phase difference film 96 is placed in such a manner that the x-axis thereof intersect with the absorption axis of the first polarizing plate 11 at right angles.

FIG. 245 shows iso-contrast curves in the case that the x-axis is employed as the phase lag axis of the phase difference film 96, namely, n_x>n_y and that the phase difference in an inplane direction in the surface of the film and the phase difference in the direction of thickness thereof are set at 55 nm and 190 nm, respectively, in the 59th embodiment. Further, FIG. 246 shows viewing angle regions, in each of which gray-scale inversion occurs during an eight-gray-scale-level driving operation in such a case. As is obvious from the comparison with FIGS. 214 and 215, a range, in which high contrast is obtained, is enlarged extensively. Moreover, the range, in which the gray-scale reversal occurs, is greatly reduced. Consequently, the viewing angle characteristics are considerably improved.

Incidentally, quantities R_xy and R_yz are defined as follows:
R_xy=(n_x−n_y)d;
and
R_yz=(n_y−n_z)d.

In the case of the 59th embodiment, the optimal condition for the contrast (ratio) was studied by changing the quantities R_xy and R_yz in various ways. FIG. 247 shows the found optimal condition for the contrast. The optimum condition shown in FIG. 247 was the same as the aforementioned condition (of FIG. 220), except that R₀ and R₁ correspond to R_xy and R_yz, respectively. These results reveal that the angles, at which the contrast ratio is 10, are not less than 39° when the quantities R_xy and R_yz satisfy the following conditions:
R_xz−250 nm≦R_yz≦R_yz+150 nm, R_yz≦−R_xz+1000 nm, 0≦R_yz and 0≦R_xz.

Incidentally, let R₀ and R₁ denote the phase difference in an inplane direction of the phase difference film 96 and the phase difference in the direction of thickness thereof, respectively. Thus, the following relations hold for these phase differences:
R₀=(n_x−n_y)d=R_xz−R_yz . . . (in the case that n_x≧n_y);
R₀=(n_y−n_x)d=R_yz−r_xz . . . (in the case that n_y≧n_x);
and
R_yz=((n_x+n_y)/2−n_z)d=(R_xz−R_yz)/2.
Therefore, the optimal conditions for R_xz and R_yz are written as follows:
R₀≦250 nm, R₁≦500 nm.

Namely, it is desirable that the inplane phase difference is not more than 250 nm and the phase difference in the direction of thickness of the film is not more than 500 nm and that the biaxial phase difference film is placed so that the phase lag axis thereof intersects with the absorption axis of the adjacent polarizing plate at right angles.

As a result of studying the relation between the retardation Δn·d caused in a liquid crystal cell and the upper limit to the optimal condition by changing the retardation Δn·d in various way within a practical range, it was found that the optimal condition for the phase difference in an inplane direction was not more than 250 nm regardless of the retardation Δn·d caused in a liquid crystal cell. In contrast, the phase difference in the direction of thickness depends on the retardation Δn·d caused in a liquid crystal cell. FIG. 248 shows the results of the study on the relation between the retardation Δn·d caused in a liquid crystal cell and the upper limit to the optimal range of the phase difference in the direction of thickness of the film. Let R_LC denote Δn·d caused in the liquid crystal. Consequently, it is concluded that the optimum value in the optimal condition for the phase difference in the direction of thickness of the phase difference film is not more than (1.7×R_LC+50) nm.

Incidentally, the optimal condition in the case of a configuration, in which a plurality of phase difference films 96 were placed in at least one of spaces formed between the liquid crystal panel and one of the first polarizing plate 11 and the second polarizing plate 15, which were provided at one or both of sides of the liquid crystal panel, and between the liquid crystal panel and the other thereof was studied similarly. As a result, it was found that the optimum condition was the case where the phase difference in the inplane direction of each of the phase difference films 96 was not more than 250 nm and that a sum of the phase differences in the direction of thickness of the phase difference films 96 was not more than (1.7×R_LC+50) nm.

Further, as a result of studying the optimal condition similarly by changing the twist angle in a range of 0 to 90°, it was found that the optimum condition was the same as the aforementioned requirement.

A positive uniaxial film (n_x>n_y=n_z), a negative uniaxial film (n_x=n_y>n_z) and a biaxial film (n_x>n_y>n_z) are employed as the film 96. Namely, a single or a combination of such films may be used.

In the foregoing description, there has been described the optimal conditions for the phase difference film in the case that alignment division is performed in a pixel by providing rows of protrusions on the liquid-crystal-side of each of the two substrates composing the liquid crystal panel. However, even in the case of performing the alignment division by using depressions or slits formed in the pixel electrodes, the viewing angle characteristics can be improved on the similar conditions.

Further, in the present specification, the polarizing plates have been described as ideal ones. Therefore, it is obvious that the phase difference (incidentally, the phase difference in the direction of thickness of the film is usually about 50 nm) caused by a film (namely, TAC (cellulose triacetate) film) protecting a polarizer should be synthesized with the phase difference caused by the phase difference film of the present invention.

Namely, the provision of the phase difference film may be omitted apparently by making TAC film meet the conditions according to the present invention. However, in this case, needless to say, such TAC film performs as well as the phase difference film of the present invention, which should be added to the device, does.

The embodiments in which the present invention is implemented in a TFT liquid crystal display have been described. The present invention can also be implemented in liquid crystal displays of other types. For example, the present invention can be implemented in a MOSFET LCD of a reflection type but not of the TFT type or in a mode using a diode such as a MIM device as an active device. Moreover, the present invention can be implemented in both a TFT mode using an amorphous silicon and a TFT mode using a polycrystalline silicon. Furthermore, the present invention can be implemented in not only a transmission type LCD but also a reflection type or plasma-addressing type LCD.

An existing TN LCD has a problem that it can cover only a narrow range of viewing angles. An IPS LCD exhibiting an improved viewing angle characteristic has problems that a response speed it can offer is not high enough and it cannot therefore be used to display a motion picture. Implementation of the present invention can solve these problems, and realize an LCD exhibiting the same viewing angle characteristic as the IPS LCD and offering a high response speed surpassing the one offered by the TN LCD. Moreover, the LCD can be realized merely by forming protrusions on substrates or slitting electrodes, and can therefore be manufactured readily. Besides, the rubbing step and after-rubbing cleaning step which are required for manufacturing the existing TN LCD and IPS LCD become unnecessary. Since these steps cause imperfect alignment, an effect of improving a yield and product reliability can also be exerted.

Since the LCD offering a high operating speed and exhibiting a good viewing angle characteristic can be realized, expansion of an application range including the application to a monitor substituting for the CRT is expected.

Claims

1. A liquid crystal display device comprising:

a liquid crystal panel in which liquid crystal having a negative dielectric constant anisotropy is sandwiched between first and second substrates, said liquid crystal is aligned in a direction vertical to said first and second substrates when no voltage is applied to said liquid crystal, and at least one of said first and second substrates includes domain regulating means for regulating said liquid crystal to be oriented in a plurality of azimuths when a voltage is applied to said liquid crystal;

first and second polarizing plates placed on both sides of said liquid crystal panel; and

at least one phase difference film, whose refractive indices n_x and n_y and refractive index n_z in a thickness direction thereof have the following relation: n_x, n_y≧n_z (except n_x=n_y=n_z), said at least one phase difference film being placed in at least one of the spaces between said liquid crystal panel and one of said first and second polarizing plates or between said liquid crystal panel and the other thereof,

wherein a phase lag axis of said at least one phase difference film intersects with an absorption axis of said first polarizing plate or second polarizing plate at a right angle, and

each inplane optical retardation of said at least one phase difference film being less than 250 nm, and a sum of optical retardations in a thickness direction of said at least one phase difference film being less than 1.7×R_1c+50 nm (r_1c: an optical retardation of a liquid crystal cell).

2. A liquid crystal display device according to claim 1, wherein when vertically seen to the substrates, said domain regulating means includes first line portions and second line portions, said first line portions being extended in a first direction, said second line portions being extended in a second direction that is different from said first direction, and neighboring ones of said first line portions being arranged approximately parallel to each other.

3. A liquid crystal display device according to claim 1,

wherein said domain regulating means includes first and second domain regulating means, and

wherein when vertically seen to the substrates, said first and second domain regulating means are arranged on said substrates so that said first domain regulating means substantially surrounds said second domain regulating means in the display areas of the pixels.

4. A liquid crystal display device comprising:

a liquid crystal panel in which a liquid crystal having a negative dielectric constant anisotropy is sandwiched between first and second substrates, said liquid crystal is aligned in a direction vertical to said first and second substrates when no voltage is applied to said liquid crystal, and at least one of said first and second substrates includes domain regulating means for regulating said liquid crystal to be oriented in a plurality of azimuths when a voltage is applied to said liquid crystal;

first and second polarizing plates placed on both sides of said liquid crystal panel;

a first phase difference film having a refractive index n_y in a direction parallel to an absorption axis of said first polarizing plate, a refractive index n_x in a direction perpendicular thereto, and a refractive index n_z in a thickness direction, the indices having the following relation: n_x>n_y=n_z, said first phase difference film being placed in space between said liquid crystal panel and said first polarizing plate; and

a second phase difference film having a refractive index n_y in a direction parallel to an absorption axis of said second polarizing plate, a refractive index n_x in a direction perpendicular thereto, and a refractive index n_z in a thickness direction, the indices having the following relation: n_x>n_y=n_z, said second phase difference film being placed in a space between said liquid crystal panel and said second polarizing plate;

wherein an inplane optical retardation r₀ of said first phase difference film and an inplane optical retardation r₁ of said second phase difference film have the following relations:

r₁≦450 nm−R₀,r₀−250 nm≦R₁≦R₀+250 nm, 0≦R₀, 0≦R₁ (except r₀=R₁=0).

5. A liquid crystal display device according to claim 4,

wherein when vertically seen to the substrates, said domain regulating means includes first line portions and second line portions, said first line portions being extended in a first direction, said second line portions being extended in a second direction that is different from said first direction, and neighboring ones of said first line portions being arranged approximately parallel to each other.

6. A liquid crystal display device according to claim 4,

wherein said domain regulating means includes first and second domain regulating means, and

wherein when vertically seen to the substrates, said first and second domain regulating means are arranged on said substrates so that said first domain regulating means substantially surrounds said second domain regulating means in the display areas of the pixels.

7. A liquid crystal display device comprising:

a liquid crystal panel in which a liquid crystal having a negative dielectric constant anisotropy is sandwiched between first and second substrates, said liquid crystal is aligned in a direction vertical to said first and second substrates when no voltage is applied to said liquid crystal, and at least one of said first and second substrates includes domain regulating means for regulating said liquid crystal to be oriented in a plurality of azimuths when a voltage is applied to said liquid crystal;

first and second polarizing plates placed on both sides of said liquid crystal panel;

a first phase difference film having a refractive index n_x in a direction parallel to an absorption axis of said first polarizing plate, a refractive index n_y in a direction perpendicular thereto, and a refractive index n_z in a thickness direction, the indices having the following relation: n_x>n_y=n_z, said first phase difference film being placed in a space between said liquid crystal panel and said first polarizing plate; and

a second phase difference film having a refractive index n_y in a direction parallel to an absorption axis of said first polarizing plate, a refractive index n_x in a direction perpendicular thereto, and a refractive index n_z in a thickness direction, the indices having the following relation: n_x>n_y=n_z, said second phase difference film being placed in a space between said first phase difference film and said first polarizing plate;

wherein an inplane optical retardation r₀ of said first phase difference film and an inplane optical retardation r₁ of said second phase difference film have the following relations:

2R₀−170 nm≦R₁≦2R₀+280 nm, r₁≦−R₀/2+800 nm, 0≦R₀, 0≦R₁ (except r₀=R₁=0).

8. A liquid crystal display device according to claim 7,

wherein when vertically seen to the substrates, said domain regulating means includes first line portions and second line portions, said first line portions being extended in a first direction, said second line portions being extended in a second direction that is different from said first direction, and neighboring ones of said first line portions being arranged approximately parallel to each other.

9. A liquid crystal display device according to claim 7,

wherein said domain regulating means includes first and second domain regulating means, and

wherein when vertically seen to the substrates, said first and second domain regulating means are arranged on said substrates so that said first domain regulating means substantially surrounds said second domain regulating means in the display areas of the pixels.

10. A liquid crystal display device comprising:

a liquid crystal panel in which a liquid crystal having a negative dielectric constant anisotropy is sandwiched between first and second substrates, said liquid crystal is aligned in a direction vertical to said first and second substrates when no voltage is applied to said liquid crystal, and at least one of said first and second substrates includes domain regulating means for regulating said liquid crystal to be oriented in a plurality of azimuths when a voltage is applied to said liquid crystal;

first and second polarizing plates placed on both sides of said liquid crystal panel; and

at least one phase difference film, whose refractive indices n_x and n_y and refractive index n_z in a thickness direction thereof have the following relation: n_x=n_y≧n_z, said at least one phase difference film being placed in at least one of the spaces between said liquid crystal panel and one of said first and second polarizing plates or between said liquid crystal panel and the other thereof,

wherein a sum of optical retardations in a thickness direction of said at least one phase difference film is less than 1.7×R_1c+50 nm (r_1c: an optical retardation of a liquid crystal cell).

11. A liquid crystal display device according to claim 10, wherein when vertically seen to the substrates, said domain regulating means includes first line portions and second line portions, said first line portions being extended in a first direction, said second line portions being extended in a second direction that is different from said first direction, and neighboring ones of said first line portions being arranged approximately parallel to each other.

12. A liquid crystal display device according to claim 10,

wherein said domain regulating means includes first and second domain regulating means, and

wherein when vertically seen to the substrates, said first and second domain regulating means are arranged on said substrates so that said first domain regulating means substantially surrounds said second domain regulating means in the display areas of the pixels.

13. A liquid crystal display device comprising:

a liquid crystal panel in which a liquid crystal having a negative dielectric constant anisotropy is sandwiched between first and second substrates, said liquid crystal is aligned in a direction vertical to said first and second substrates when no voltage is applied to said liquid crystal, and at least one of said first and second substrates includes domain regulating means for regulating said liquid crystal to be oriented in a plurality of azimuths when a voltage is applied to said liquid crystal;

first and second polarizing plates placed on both sides of said liquid crystal panel;

a first phase difference film having a refractive index n_y in a direction parallel to an absorption axis of said first polarizing plate, a refractive index n_x in a direction perpendicular thereto, and a refractive index n_z in a thickness direction, the indices having the following relation: n_x>n_y=n_z, said first phase difference film being placed in a space between said liquid crystal panel and said first polarizing plate; and

a second phase difference film, whose refractive indices n_x and n_y and refractive index n_z in a thickness direction thereof have the following relation: n_x=n_y≧n_z, said second phase difference film being placed in a space between said liquid crystal panel and said second polarizing plate,

wherein an inplane optical retardation r₀ of said first phase difference film and an inplane optical retardation r₁ in a thickness direction of said second phase difference film have the following relation:

8R₀−13R₁≦1950 nm, 0≦R₀≦400, 0≦R₁≦400 (except r₀=R₁=0).

14. A liquid crystal display device according to claim 13,

wherein when vertically seen to the substrates, said domain regulating means includes first line portions and second line portions, said first line portions being extended in a first direction, said second line portions being extended in a second direction that is different from said first direction, and neighboring ones of said first line portions being arranged approximately parallel to each other.

15. A liquid crystal display device according to claim 13,

wherein said domain regulating means includes first and second domain regulating means, and

wherein when vertically seen to the substrates, said first and second domain regulating means are arranged on said substrates so that said first domain regulating means substantially surrounds said second domain regulating means in the display areas of the pixels.

16. A liquid crystal display device comprising:

a liquid crystal panel in which a liquid crystal having a negative dielectric constant anisotropy is sandwiched between first and second substrates, said liquid crystal is aligned in a direction vertical to said first and second substrates when no voltage is applied to said liquid crystal, and at least one of said first and second substrates includes domain regulating means for regulating said liquid crystal to be oriented in a plurality of azimuths when a voltage is applied to said liquid crystal;

first and second polarizing plates placed on both sides of said liquid crystal panel;

a first phase difference film having a refractive index n_y in a direction parallel to an absorption axis of said first polarizing plate, a refractive index n_x in a direction perpendicular thereto, and a refractive index n_z in a thickness direction, the indices having the following relation: n_x>n_y=n_z, said first phase difference film being placed in a space between said liquid crystal panel and said first polarizing plate; and

a second phase difference film, whose refractive indices n_x and n_y, and refractive index n_z in a thickness direction thereof have the following relation: n_x=n_y≧n_z, said second phase difference film being placed in a space between said first polarizing plate and said first phase difference film,

wherein an inplane optical retardation r₀ of said first phase difference film and an optical retardation r₁ in a thickness direction of said second phase difference film have the following relations:

5R₁+16R₀≦3310 nm, 19R₁+28R₀≦7330 nm, 0≦R₀≦400, 0≦R₁≦400 (except r₀=R₁=0).

17. A liquid crystal display device according to claim 16,

wherein when vertically seen to the substrates, said domain regulating means includes first line portions and second line portions, said first line portions being extended in a first direction, said second line portions being extended in a second direction that is different from said first direction, and neighboring ones of said first line portions being arranged approximately parallel to each other.

18. A liquid crystal display device according to claim 16,

wherein said domain regulating means includes first and second domain regulating means, and

wherein when vertically seen to the substrates, said first and second domain regulating means are arranged on said substrates so that said first domain regulating means substantially surrounds said second domain regulating means in the display areas of the pixels.

19. A liquid crystal display device comprising:

a liquid crystal panel in which a liquid crystal having a negative dielectric constant anisotropy is sandwiched between first and second substrates, said liquid crystal is aligned in a direction vertical to said first and second substrates when no voltage is applied to said liquid crystal, and at least one of said first and second substrates includes domain regulating means for regulating said liquid crystal to be oriented in a plurality of azimuths when a voltage is applied to said liquid crystal;

first and second polarizing plates placed on both sides of said liquid crystal panel;

a first phase difference film having a refractive index n_y in a direction parallel to an absorption axis of said first polarizing plate, a refractive index n_x in a direction perpendicular thereto, and a refractive index n_z in a thickness direction, the indices having the following relation: n_x>n_y=n_z, said first phase difference film being placed in a space between said liquid crystal panel and said first polarizing plate; and

a second phase difference film, whose refractive indices n_x and n_y and refractive index n_z in a thickness direction thereof have the following relation: n_x=n_y≧n_z, said second phase difference film being placed in a space between said liquid crystal panel and said first phase difference film,

wherein an optical retardation r₀ in a thickness direction of said second phase difference film and inplane optical retardation r₁ of said first phase difference film have the following relation:

8R₁−13R₀≦1950 nm, 0≦R₀≦400, 0≦R₁≦400 (except r₀=R₁=0).

20. A liquid crystal display device according to claim 19,

wherein when vertically seen to the substrates, said domain regulating means includes first line portions and second line portions, said first line portions being extended in a first direction, said second line portions being extended in a second direction that is different from said first direction, and neighboring ones of said first line portions being arranged approximately parallel to each other.

21. A liquid crystal display device according to claim 19,

wherein said domain regulating means includes first and second domain regulating means, and

wherein when vertically seen to the substrates, said first and second domain regulating means are arranged on said substrates so that said first domain regulating means substantially surrounds said second domain regulating means in the display areas of the pixels.

22. The liquid crystal display device of claim 2, wherein said first line portions and said second line portions are protrusions formed on an electrode.

23. The liquid crystal display device of claim 2, wherein said first line portions and said second line portions are depressions formed in an electrode.

24. The liquid crystal display device of claim 2, wherein said first line portions and said second line portions are slits formed in an electrode.

25. The liquid crystal display device of claim 2, wherein said first line portions and said second line portions are each zig-zag shaped.

26. The liquid crystal display device of claim 2, wherein said first line portions and said second line portions are connected via bend portions.

27. The liquid crystal display device of claim 24, wherein said first line portions and said second line portions are connected via bend portions.

28. The liquid crystal display device of claim 2, further comprising a supplemental structure extending from at least one of the first line portions and the second line portions along an edge of a pixel of the liquid crystal display device.

29. The liquid crystal display device of claim 28, wherein said supplemental structure comprises a protrusion.

30. The liquid crystal display device of claim 1, wherein the refractive indices n_x, n_y, and n_z of the phase difference film are characterized by n_x>n_y>n_z.

31. The liquid crystal display device of claim 1, wherein said domain regulating means comprises a plurality of protrusions.

32. The liquid crystal display device of claim 1, wherein said domain regulating means comprises a plurality of slits in at least one electrode.

33. The liquid crystal display device of claim 1, wherein said domain regulating means comprises at least one protrusion on the first substrate and at least one slit defined in an electrode on the second substrate.

34. The liquid crystal display device of claim 1, wherein said domain regulating means comprises: (a) protrusions on the first substrate, and/or (b) at least one slit defined in an electrode on the second substrate.

35. The liquid crystal display device of claim 1, wherein said domain regulating means comprises at least one protrusion at least part of which is V-shaped as viewed from above.

36. The liquid crystal display device of claim 1, wherein said domain regulating means comprises at least one zig-zag shaped protrusion.

37. The liquid crystal display device of claim 1, wherein said domain regulating means comprises at least one substantially V-shaped slit in an electrode.

38. The liquid crystal display device according to claim 1, wherein said domain regulating means includes first line portions and second line portions in a pixel,

said first line portions being extended in a first direction,

said second line portions being extended in a second direction that is different from said first directions, and

neighboring ones of said first line portions being arranged on different substrates.

39. The liquid crystal display device of claim 38, wherein refractive indices n_x, n_y, and n_z of the phase difference film are characterized by n_x>n_y>n_z.

40. The liquid crystal display device of claim 38, wherein said domain regulating means comprises a plurality of protrusions.

41. The liquid crystal display device of claim 38, wherein said domain regulating means comprises a plurality of slits in at least one electrode.

42. The liquid crystal display device of claim 38, wherein said domain regulating means comprises at least one protrusion on the first substrate and at least one slit defined in an electrode on the second substrate.

43. The liquid crystal display device of claim 38, wherein said domain regulating means comprises: (a) protrusions on the first substrate, and/or (b) at least one slit defined in an electrode on the second substrate.

44. The liquid crystal display device of claim 38, wherein said domain regulating means comprises at least one protrusion at least part of which is V-shaped as viewed from above.

45. The liquid crystal display device of claim 38, wherein said domain regulating means comprises at least one zig-zag shaped protrusion.

46. The liquid crystal display device of claim 38, wherein said domain regulating means comprises at least one substantially V-shaped slit in an electrode.

47. The liquid crystal display device of claim 38, wherein said first line portions and second line portions are protrusions formed on an electrode.

48. The liquid crystal display device of claim 38, wherein said first line portions and said second line portions are depressions formed in an electrode.

49. The liquid crystal display device of claim 38, wherein said first line portions and said second line portions are slits formed in an electrode.

50. The liquid crystal display device of claim 49, wherein said first line portions and said second line portions are connected via bend portions.

51. The liquid crystal display device of claim 38, wherein said first line portions and said second line portions are each zig-zag shaped.

52. The liquid crystal display device of claim 38, wherein said first line portions and said second line portions are connected via bend portions.

53. The liquid crystal display device of claim 38, further comprising a supplemental structure extending from at least one of the first line portions and the second line portions along an edge of a pixel of the liquid crystal display device.

54. The liquid crystal display device of claim 53, wherein said supplemental structure comprises a protrusion.