Liquid crystal display device

A liquid crystal panel includes a TFT substrate, an opposite substrate and a liquid crystal layer formed of a liquid crystal, which is filled in a space between the TFT and the opposite substrates, and has a negative dielectric anisotropy. A quarter wave plate and a polarizer are arranged on a front surface of the liquid crystal panel, and a quarter wave plate and a polarizer are arranged on a back surface thereof. An optical compensation layer is formed on a surface of the opposite substrate facing the liquid crystal layer. The optical compensation layer is divided into a plurality of regions for each picture element, and the respective regions are made of polymer films, each having a different compensation capability Rth in a thickness direction.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims priority of Japanese Patent Application No. 2005-60220 filed on Mar. 4, 2005 the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an MVA (Multi-domain Vertical Alignment) mode liquid crystal display device, and particularly to a liquid crystal display device in which a quarter wave plate is placed between a liquid crystal panel and a polarizer.

2. Description of the Prior Art

In general, a liquid crystal display device is composed of a liquid crystal panel, in which a liquid crystal is filled in a space between two substrates, and polarizers respectively placed on each of both sides of the liquid crystal panel. A picture element electrode is formed on one substrate of the liquid crystal panel for each picture element, and a common electrode common to each picture element is formed on the other substrate. When a voltage is applied between the picture element electrode and the common electrode, an alignment direction of liquid crystal molecules is changed according to the voltage, as a result, an amount of light, which passes through the liquid crystal panel and the polarizers provided on both sides thereof, is changed. The applied voltage is controlled for each picture element, thereby it is possible to display various images on the liquid crystal display device.

In a TN (Twisted Nematic) mode liquid crystal display device that has been heretofore widely used, the liquid crystal with a positive dielectric anisotropy is used and liquid crystal molecules are twist-aligned between two substrates. However, in the TN mode liquid crystal display device, there is a drawback in which a viewing angle characteristic is insufficient, gradation and contrast are considerably deteriorated, and in an extreme case, displayed images are reversed when the liquid crystal panel is looked at from an oblique direction.

An MVA (Multi-domain Vertical Alignment) mode liquid crystal display device using a liquid crystal with a negative dielectric anisotropy has been known as a liquid crystal display device having an excellent viewing angle characteristic. In the general MVA mode liquid crystal display device, protrusions (alignment control protrusions), which are formed of a dielectric material and extend in an oblique direction, are formed on the common electrode, and slits (alignment control slits) in parallel with the protrusions are formed on a picture element electrode.

In the MVA mode liquid crystal display device, liquid crystal molecules are oriented in a direction perpendicular to a substrate surface in a state where no voltage is applied, and when a voltage is applied to between the picture element electrode and the common electrode, the liquid crystal molecules are inclined and oriented at an angle according to the voltage. At this time, a plurality of regions (domains) where tilting directions of liquid crystal molecules are different from one another due to the slits formed on the picture element electrode and protrusions are formed in one picture element. Accordingly, a plurality of domains where tilting directions of liquid crystal molecules are different from one another are formed in one picture element, thereby it is possible to suppress leakage light in an oblique direction and to obtain a satisfactory viewing angle characteristic. Moreover, the MVA mode liquid crystal display device has a manufacturing advantage that eliminates a process for rubbing an alignment layer.

However, in the MVA mode liquid crystal display device, there is a drawback in which light transmittance is lower and display becomes darker unless strong backlight is used as compared with the TN mode liquid crystal display device. This is caused when the inclined orientations of the liquid crystal molecules in the edge of the protrusions and slits are shifted from predetermined orientations decided by orientations of absorption axes of polarizer and analyzer (hereinafter referred to as polarizers).

In order to solve the above drawback, Japanese Patent Laid-open Publication No. 2001-318371 proposes that circular polarizers (λ/4 plates) are respectively placed between the liquid crystal panel and a polarizer of a back surface side (backlight side), and between the liquid crystal panel and a polarizer of a front surface side (light outgoing side). These two quarter wave plates are arranged in such a manner that their slow axes are orthogonal to each other and each of the slow axes makes an angle of 45° with an absorption axis of each of adjacent polarizers. As mentioned above, the quarter wave plates are respectively placed between the liquid crystal panel and the polarizer of the back surface side, and between the liquid crystal panel and the polarizer of the front surface side, so that light passing through a liquid crystal layer is converted into a circurlar polarized light. In the case of the circurlar polarized light, the influence of the inclined orientation of the liquid crystal molecules in the edge of the protrusions and slits and the influence of the inclined orientation of the liquid crystal molecules at the picture element end portions are eliminated, thereby it is possible to improve light transmittance and provide a bright liquid crystal display device.

However, in the MVA mode liquid crystal display device using the aforementioned quarter wave plates, the viewing angle characteristic is deteriorated as compared with the MVA liquid crystal display device using no quarter wave plate. For this reason, there has been proposed an MVA mode liquid crystal display device in which an optical compensation layer is placed between a quarter wave plate and a liquid crystal panel to suppress deterioration in the viewing angle characteristic. The optical compensation layer is formed to compensate for a negative retardation which a liquid crystal layer has, and there is used a polymer film in which the relationship of Nx=Ny>Nz is established when refractive indexes in an in-plane direction are Nx and Ny and a refractive index in a thickness direction is Nz.

However, sufficient improvement in the viewing angle characteristic cannot be obtained by placing only the optical compensation layer between the liquid crystal panel and the quarter wave plate, and further improvement in the viewing angle characteristic has been demanded.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an MVA mode liquid crystal display device having an excellent viewing angle characteristic as compared with the conventional one.

The above-mentioned problem can be solved by a liquid crystal display device including: a liquid crystal panel formed of first and second substrates arranged opposite to each other and of a liquid crystal layer formed of liquid crystal, which is filled in a space therebetween and has a negative dielectric anisotropy; first and second polarizers arranged to sandwich the liquid crystal panel; a first quarter wave plate placed between the liquid crystal panel and the first polarizer; a second quarter wave plate placed between the liquid crystal panel and the second polarizer; and an optical compensation layer, which has a plurality of regions, each having a different compensation capability Rth in a thickness direction for each picture element and is placed between the first and second quarter wave plates.

According to the present invention, the optical compensation layer, which has a plurality of regions, each of which has a different compensation capability Rth in a thickness direction for each picture element, is placed between the first and second quarter wave plates. In the liquid crystal display device using the liquid crystal having a negative dielectric anisotropy, it is necessary to use the optical compensation layer having a positive refractive index anisotropy in order to compensate for a negative refractive index anisotropy of the liquid crystal layer. In this case, a compensation capability Rth in the thickness direction of the optical compensation layer can be defined by Rth=((Nx+Ny)/2−Nz)×d where refractive indexes in an in-plane direction are Nx and Ny and a refractive index in a thickness direction is Nz among the main refractive indexes of the optical compensation layer. In addition, d is a thickness of the optical compensation layer.

The viewing angle characteristic of the liquid crystal display device is decided by a relationship between the negative refractive index anisotropy of the liquid crystal layer and the compensation capability of the optical compensation layer. The optical compensation layer cancels the negative retardation of the liquid crystal layer. For this reason, if the optical compensation layer is placed between the first and second quarter wave plates, the effect that is given to the viewing angle characteristic of the liquid crystal display device is the same in the case where the total sum of the compensation capabilities of the optical compensation layers is constant even if the optical compensation layer is placed between the liquid crystal layer and the first quarter wave plate, between the liquid crystal layer and the second quarter wave plate, or both between the liquid crystal layer and the first quarter wave plate and between the liquid crystal layer and the second quarter wave plate. Moreover, a material such as glass showing an optical isotropy does not have an influence upon passing light. Accordingly, for example, when a pair of glass substrates are arranged to sandwich the liquid crystal layer, the effect that is given to the viewing angle characteristic of the liquid crystal display device is the same even if the optical compensation layer is placed on the inner side of the pair of glass substrates (namely, the optical compensation layer is placed adjacent to the liquid crystal layer) or on the outer side of the pair of glass substrates. When the plurality of regions, each having a different compensation capability, are formed in one picture element as described in the present invention, the entire viewing angle characteristic is one that is obtained by averaging the viewing angle characteristics of the respective regions. This improves the viewing angle characteristic of the liquid crystal display device as compared with a case where an optical compensation layer has only a single compensation capability.

In addition, Japanese Patent Laid-open No. 10-62623 describes a liquid crystal display device including an optical anisotropic film with a plurality of regions, each having a different direction of an optical axis in one picture element. However, in order to form such an optical anisotropic film, it is necessary to provide a process for performing several rubbing processes, a process for coating a solvent containing a polymer liquid crystal or a discotic-type liquid crystal, and a process for fixing an alignment direction, and therefore, there is a drawback that the manufacture of the liquid crystal display device becomes complicated.

On the other hand, in the present invention, for example, since the polymer film having a refractive index anisotropy may be formed with a thickness different for each region, there is an advantage in which the manufacture of the liquid crystal display device can be easily manufactured as compared with the liquid crystal display device described in Japanese Patent Laid-open No. 10-62623.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention will be explained specifically as follows.

FIG. 1is a schematic view illustrating one example of an MVA mode liquid crystal display device. The liquid crystal display device includes a liquid crystal panel10, quarter wave plates15a,15bbonded to the liquid crystal panel10, polarizers16a,16b, and a backlight19placed on a back surface side of the liquid crystal panel10.

The liquid crystal panel10includes first and second substrates11,12, and a liquid crystal layer13formed of a liquid crystal, which is filled in a space between these substrates and has a negative dielectric anisotropy. A TFT (Thin Film Transistor), a picture element electrode and the like are formed on the first substrate11, and a color filter, a common electrode and the like are formed on the second substrate12. In this liquid crystal display device, an optical compensation layer14is formed on a surface of the second substrate12facing the liquid crystal layer13. In two substrates that form the liquid crystal panel, a substrate on which a TFT is formed is hereinafter referred to as a TFT substrate and the other substrate placed opposite to the TFT substrate is hereinafter referred to as an opposite substrate.

A quarter wave plate15ais bonded onto the back surface of the liquid crystal panel10with an adhesive17aand a polarizer16ais bonded onto the quarter wave plate15a(lower side inFIG. 1) with an adhesive18a. Moreover, a quarter wave plate15bis bonded onto the front surface of the liquid crystal panel10with an adhesive17b, and a polarizer16bis bonded onto the quarter wave plate15bwith an adhesive18b.

In the above-configured liquid crystal display device, by passing through the polarizer16a, light emitted from the backlight19is converted into a linearly polarized light, and by further passing through the quarter wave plate15a, the linearly polarized light is converted into a circurlar polarized light. The circurlar polarized light is converted into a linearly polarized light in passing through the quarter wave plate15b.

By the way, since a traveling direction of light, which has passed through the quarter wave plate15a, is changed by a negative refractive index anisotropy of the liquid crystal layer13in passing through the liquid crystal layer13, the negative refractive index anisotropy of the liquid crystal layer13must be compensated in order to obtain a satisfactory display quality. For this reason, in the liquid crystal display device shown inFIG. 1, an optical compensation layer14is placed on the surface of the second substrate (opposite substrate)12facing the liquid crystal layer13.

In order to compensate for the negative refractive index anisotropy of the liquid crystal layer13, the optical compensation layer14must have a positive refractive index anisotropy. Namely, regarding the optical compensation layer14, the relationship of Nx=Ny>Nz must be established when refractive indexes in an in-plane direction are Nx and Ny and the refractive index in a thickness direction is Nz. In this case, a compensation capability Rth in the thickness direction of the optical compensation layer14can be expressed by the following equation (1):
Rth=((Nx+Ny)/2−Nz)×d(1).
In this case, d is a thickness of the optical compensation layer14.

The optical compensation layer14preferably has equal refractive indexes (that is, Nx=Ny>Nz) in the in-plane direction. When the refractive indexes in the in-plane direction of the optical compensation layer14are equal to each other, light as the circurlar polarized light can pass through the optical compensation layer14.

The relationship between the value of the compensation capability Rth in the thickness direction of the optical compensation layer14and retardation RLC, which the liquid crystal layer13has, is changed, and therefore, the viewing angle characteristic of the liquid crystal display device is changed.

A viewing angle characteristic is generally expressed by a view illustrating viewing angle to evaluate the viewing angle characteristic.FIGS. 2A to 2Fare views illustrating viewing angle, each showing a result when the compensation capability Rth in the direction of the thickness of the optical compensation layer is changed. In each ofFIGS. 2A to 2F, an azimuth is taken in a circumferential direction and a polar angle is taken in a concentric circular manner to illustrate iso-contrast contours. In addition, an angle, which is formed by a line obtained by projecting a sight line onto the liquid crystal panel, and an X axis (straight line extending in a right direction with the center of the liquid crystal panel as the origin) of the liquid crystal panel, is called an azimuth and an angle, which is formed by a normal line of the liquid crystal panel and the sight line, is called a polar angle. Moreover, inFIGS. 2A to 2F, a line drawn at an innermost position is an iso-contrast contour with a contrast of 100:1, and a line drawn at an outermost position is an iso-contrast contour with a contrast of 10:1.

FIG. 2Ais iso-contrast contours when the compensation capability Rth in the thickness direction of the optical compensation layer is 0 (Rth=0 nm);FIG. 2Bis iso-contrast contours when the compensation capability Rth in the thickness direction of the optical compensation layer is 80 nm (Rth=80 nm);FIG. 2Cis iso-contrast contours when the compensation capability Rth in the thickness direction of the optical compensation layer is 120 nm (Rth=120 nm);FIG. 2Dis iso-contrast contours when the compensation capability Rth in the thickness direction of the optical compensation layer is 160 nm (Rth=160 nm);FIG. 2Eis iso-contrast contours when the compensation capability Rth in the thickness direction of the optical compensation layer is 200 nm (Rth=200 nm); andFIG. 2Fis iso-contrast contours when the compensation capability Rth in the direction of the thickness of the optical compensation layer is 240 nm (Rth=240 nm). It is noted that retardation RLCof the liquid crystal layer is 340 nm in any case.

As illustrated inFIGS. 2A to 2F, when the retardation RLCof the liquid crystal layer is constant, the iso-contrast contour is changed depending on the compensation capability Rth of the optical compensation layer. In this example, the orientation, at which the contrast is improved best, is moved in a right direction along the circumference as the compensation capability Rth of the optical compensation layer is increased. Then, when the compensation capability Rth of the optical compensation layer is 240 nm, the contrast is improved best when viewing from the direction of each of the azimuths of 0°, 90°, 180°, and 270° (i.e., the direction of each of the left, right, top and bottom).

Accordingly, in the present embodiment, as illustrated schematically inFIG. 3, one picture element is divided into a plurality of regions (two regions inFIG. 3), and polymer films21aand21b, each of which has a different compensation capability Rth in the thickness direction for each region, are formed to provide an optical compensation layer21. As described above, when the plurality of polymer films, each of which has a different compensation capability Rth in the thickness direction, are formed in each region to serve as the optical compensation layer21, the entire viewing angle characteristic is one that is obtained by averaging the viewing angle characteristics of the respective regions.

Additionally, inFIG. 3, the same elements as those inFIG. 1are assigned the same reference numerals as inFIG. 1. Moreover, inFIG. 3, although the optical compensation layer21is placed on the surface of the second substrate (opposite substrate)12facing the liquid crystal layer13, the optical compensation layer21may be placed between two quarter wave plates15aand15b. For example, the optical compensation layer21may be placed on the surface of the first substrate (TFT substrate)11facing the liquid crystal layer13and the optical compensation layer21may be placed between the liquid crystal panel10and the quarter wave plate15aor15b.

The embodiment of the present invention will be explained specifically as follows.

FIG. 4is a plan view illustrating a liquid crystal display device according to the embodiment of the present invention, andFIG. 5is a schematic cross sectional view of the same. Additionally, inFIG. 4, regions for three picture elements are illustrated.

As illustrated inFIG. 5, a liquid crystal panel100includes a TFT substrate110, an opposite substrate120, and a liquid crystal layer130formed of a liquid crystal, which is filled in a space between these substrates110and120and has a negative dielectric anisotropy. A quarter wave plate141aand a polarizer142aare arranged on a back surface of the liquid crystal panel100, and a quarter wave plate141band a polarizer142bare arranged on a front surface thereof. These two polarizers142aand142bare arranged in such a manner that their polarizing axes are orthogonal to each other. Moreover, the quarter wave plates141aand141bare arranged in such a manner that their slow axes are orthogonal to each other and each of the slow axes makes an angle of 45° with an absorption axis of each of adjacent polarizers. A backlight140is placed on the back surface of the liquid crystal panel100.

As illustrated inFIG. 4, on the TFT substrate110, there are formed a plurality of gate bus lines112aextending in a horizontal direction (X-axis direction) and a plurality of data bus lines113extending in a vertical direction (Y-axis direction). The gate bus lines112aare arranged in a vertical direction at predetermined intervals (for example, about 300 μm) and the data bus lines113are arranged in a horizontal direction at predetermined intervals (for example, about 100 μm). Rectangular regions, which are divided by these gate bus lines112aand data bus lines113, are picture element regions, respectively. Furthermore, on the TFT substrate110, an auxiliary capacitance bus line112bis formed so as to be in parallel with the gate bus lines112aand to cross over a central position of each picture element region.

For each picture element, a TFT114, a picture element electrode116and an auxiliary capacitance electrode115are formed. The TFT114is placed in the vicinity of a crossing position of the gate bus line112aand the data bus line113. A drain electrode114cof the TFT114is electrically connected to the data bus line113.

The picture element electrode116is formed of a transparent conductive material such as ITO (indium-Tin Oxide). The picture element electrode116includes alignment control slits116aalong a zigzag imaginary line (shown by a broken line in the figure), which is bent on the gate bus line112aand the auxiliary capacitance bus line112b. Moreover, the picture element electrode116is electrically connected to a source electrode114bof the TFT114through a contact hole133aand is electrically connected to the auxiliary capacitance electrode115through a contact hole133b.

A layered structure of each of the TFT substrate110and the opposite substrate120will be explained with reference toFIG. 5as follows. First, the layered structure of the TFT substrate110will be explained.

On a glass substrate111serving as a base of the TFT substrate110, the gate bus line112aand the auxiliary capacitance bus line112bare formed. These gate bus line112aand the auxiliary capacitance bus line112bare formed simultaneously by patterning, by a photolithographic method, a metal film on which for example, Al(aluminum)/Ti(titanium) are superimposed. On the glass substrate111, there is formed a first insulating film (gate insulating film)131that covers these gate bus line112aand auxiliary capacitance bus line112b. The first insulating film131is formed of, for example, SiO2or SiN.

On a predetermined region of the first insulating film131, there is formed a semiconductor film (amorphous silicon or polysilicon film)114aserving as an active layer for the TFT114. Moreover, on a region serving as a channel for the semiconductor film114a, there is formed a channel protection film132made of SiN. A source electrode114band a drain electrode114cof the TFT114are arranged at a position where they are opposed to each other with the channel protection film132interposed therebetween.

Furthermore, on the first insulating film131, the data bus line113and the auxiliary capacitance electrode115are formed. The data bus line113extends in a direction orthogonal to the gate bus line112aand is connected to the drain electrode114cof the TFT114as mentioned above. Moreover, the auxiliary capacitance electrode115is placed at a position opposed to the auxiliary capacitance bus line112bwith the first insulating film131interposed therebetween. The auxiliary capacitance is formed of the auxiliary capacitance electrodes115, the first insulating film131, and the auxiliary capacitance bus line112b. The data bus line113, the source electrode114b, the drain electrode114cand the auxiliary capacitance electrode115are formed simultaneously by patterning, by the photolithographic method, a metal film on which, for example, Ti/Al/Ti/ are superimposed.

The data bus line113, the source electrode114b, the drain electrode114cand the auxiliary capacitance electrode115are covered with a second insulating film133made of, for example, SiO2or SiN. Then, the picture element electrode116, made of a transparent conductive material such as ITO, is formed on the second insulating film133. As mentioned above, the slits (alignment control structures)116aextending in the oblique direction are formed in the picture element electrode116. Moreover, the picture element electrode116is electrically connected to the source electrode114bthrough the contact hole133aformed in the second insulating film133and is further electrically connected to the auxiliary capacitance electrode115through the contact hole133b. The surface of the picture element electrode116is covered with a vertical alignment layer (not shown), which is made of, for example, polyimide.

On the other hand, the opposite substrate120includes a glass substrate121serving as a base, a black matrix122, an optical compensation layer123, a color filter124, a common electrode125, and protrusions (alignment control structures)126. The black matrix122is formed of metal such as Cr (chromium) or a black resin, and is placed at a position opposite to the gate bus line112a, the data bus line113, and the TFT114of the TFT substrate110.

The optical compensation layer123includes two polymer films123aand123b, each of which has a different compensation capability Rth in the thickness direction for each picture element. In the present embodiment, each of the polymer films123aand123bhas the same quality of material and a different thickness. Each of the polymer films123aand123bmay have the same thickness and a different quality of material.

The color filter124is formed on the optical compensation layer123(lower side inFIG. 5). The color filter124includes three kinds of red (R), green (G), and blue (B), and the color filter124of any one of red (R), green (G), and blue (B) is placed at the position opposite to the picture element electrode116of each picture element.

On the color filter124(lower side inFIG. 5), there is formed the common electrode125made of a transparent conductive material such as ITO. Then, as illustrated inFIG. 5, the protrusions126, which are made of a dielectric material, are formed under the common electrode125. The protrusions126are made of, for example, a photoresist, and are placed between lines of the slits116aof the picture element electrode116as indicated by alternate long and short dash lines inFIG. 4. The surfaces of these common electrode125and protrusions126are covered with the vertical alignment layer (not shown) which is made of, for example, polyimide.

FIGS. 6A to 6Eare schematic views, each showing a method of forming the optical compensation layer123. First, as illustrated inFIG. 6A, the upper entire surface of the glass substrate121is coated with a photosensitive polymer film material to have a first thickness, thereby the polymer film123ais formed. Next, as illustrated inFIG. 6B, the polymer film123ais exposed through an exposure mask151. After that, a developing process is performed to cause the polymer film123ato be left in only the first region as illustrated inFIG. 6C.

Next, as illustrated inFIG. 6D, the upper entire surface of the glass substrate121is coated with a photosensitive polymer film material to have a second thickness, thereby the polymer film123bis formed. Next, the polymer film123ais exposed through the exposure mask and thereafter a developing process is performed to cause the polymer film123bto be left in only the second region as illustrated inFIG. 6E.

In this way, the polymer films123aand123b, each having a different compensation capability Rth in the thickness direction can be formed in one picture element.

An examined result of the viewing angle characteristic after actually manufacturing the liquid crystal display device of the present embodiments will be explained as follows.

The liquid crystal display device having the structure as illustrated inFIGS. 4 and 5was manufactured. However, on the opposite substrate120, there were formed the polymer films123aand123bas the optical compensation layer123where their compensation capabilities Rth in the thickness direction were 80 nm and 240 nm, respectively. An area ratio between the polymer films123aand123bwas 1:1. Moreover, a liquid crystal having a negative dielectric anisotropy was used as a liquid crystal that forms the liquid crystal layer130.

The quarter wave plate141awas bonded to the back surface of the liquid crystal panel100, and the polarizer142awas placed on the quarter wave plate141a(lower side inFIG. 5) with TAC (triacetyl-cellulose) interposed therebetween. Moreover, the quarter wave plate141bwas bonded to the front surface of the liquid crystal panel100, and the polarizer142bwas placed on the quarter wave plate141bwith the TAC film interposed therebetween. The polarizers142aand142bwere arranged that their optical absorption axes were orthogonal to each other. Moreover, the quarter wave plates141aand141bwere arranged that their slow axes were orthogonal to each other and each of the slow axes made an angle of 45° with an absorption axis of each of adjacent polarizers. In addition, the value of retardation RLCof the liquid crystal layer130was 340 nm.

FIG. 7is a view illustrating viewing angle of the liquid crystal display device of Example 1. InFIG. 7, a line drawn at an innermost position is an iso-contrast contour with a contrast of 100:1, and a line drawn at an outermost position is an iso-contrast contour with a contrast of 10:1. The comparison betweenFIG. 7and each ofFIGS. 2A to 2Fshows that a range where satisfactory contrast can be obtained is wide and the viewing angle characteristic is largely improved in the liquid crystal display device of Example 1.

The liquid crystal display device of Example 2 was manufactured in the same way as Example 1. However, in Example 2, one picture element was divided into three regions to form polymer films as the optical compensation layer where each film has a different compensation capability in the thickness direction for each region. Namely, the polymer film with 80 nm of the compensation capability Rth in the thickness direction was formed in the first region, the polymer film with 120 nm of the compensation capability Rth in the thickness direction was formed in the second region, and the polymer film with 240 nm of the compensation capability Rth in the thickness direction was formed in the third region. In addition, an area ratio among these polymer films was 1:1:1. Moreover, the value of retardation RLCof the liquid crystal layer was 340 nm, which was the same as Example 1.

FIG. 8is a view illustrating viewing angle of the liquid crystal display device of Example 2. InFIG. 8, a line drawn at an innermost position is an iso-contrast contour with a contrast of 100:1, and a line drawn at an outermost position is an iso-contrast contour with a contrast of 10:1. The comparison betweenFIG. 8and each ofFIGS. 2A to 2Fshows that a range where satisfactory contrast can be obtained is wide and the viewing angle characteristic is largely improved in the liquid crystal display device of Example 2.