KR100579545B1 - In Plane Switching mode Liquid crystal display device - Google Patents

Abstract

end. Fields to which the invention described in the claims belong:

In-plane switching mode liquid crystal display with improved image quality deterioration due to wide viewing angle and viewing angle.

I. The technical problem the invention is trying to solve:

To improve the color shift and gray level inversion in the middle gray scale, which are fatal problems of the liquid crystal display.

All. The gist of the solution of the invention:

In a liquid crystal display device operating in an in-plane switching (IPS) mode, a pixel electrode and a common electrode are arranged to form a fringe field, thereby forming domains having at least two different directions in one pixel to form a domain of the liquid crystal display device. Improves the image quality reduction characteristic according to the viewing angle. To this end, the present invention proposes a method of disturbing the direction of an electric field applied to each electrode by forming a plurality of dielectric protrusions having different dielectric constants from the liquid crystal on the electrodes.

Description

In-Plane Switching mode Liquid crystal display device             

1 is a cross-sectional view showing a cross section corresponding to one pixel portion of a general liquid crystal display device.

2A and 2B illustrate the operation of the TN mode liquid crystal display device.

3 is a cross-sectional view showing a cross section corresponding to one pixel portion of a liquid crystal display device in a general IPS mode.

4A and 4B are perspective views illustrating the operation of a general IPS mode LCD.

5A and 5B are plan views showing the operation of a liquid crystal display device in a general IPS mode.

6 is a view illustrating color coordinates according to a viewing angle of a general IPS mode liquid crystal display.

7 is a diagram illustrating transmittance according to a viewing angle according to each gray level of a general liquid crystal display.

8A shows the path of light for a single domain of liquid crystal molecules.

8B shows the path of light for multi-domain liquid crystal molecules.

9 illustrates a liquid crystal display device in an IPS mode according to a first embodiment of the present invention.

FIG. 10 is an enlarged view of a portion Z of FIG. 9; FIG.

11 illustrates rotation of liquid crystal molecules along an alignment direction.

FIG. 12 is a cross-sectional view taken along cut line XII-XII of FIG. 10. FIG.

FIG. 13 illustrates a liquid crystal display device in an IPS mode according to a second embodiment of the present invention. FIG.

<Explanation of symbols for the main parts of the drawings>

50: gate wiring 52: gate electrode

60: common wiring 62: common electrode

76: pixel electrode 90: dielectric projection

The present invention relates to an image display device, and more particularly, to a liquid crystal display (LCD) including a thin film transistor (TFT).

In particular, the present invention relates to a liquid crystal display of an in-plane switching (hereinafter referred to as IPS mode) in which first and second electrodes for driving a liquid crystal of a liquid crystal display are formed on the same substrate.

In general, the driving principle of the liquid crystal display device uses the optical anisotropy and polarization of the liquid crystal. Since the liquid crystal is thin and long in structure, the liquid crystal has directivity in the arrangement of molecules, and the direction of the molecular arrangement can be controlled by artificially applying an electric field to the liquid crystal.

Accordingly, when the molecular arrangement direction of the liquid crystal is arbitrarily adjusted, the molecular arrangement of the liquid crystal is changed, and light polarized by optical anisotropy may be arbitrarily modulated to express image information.

Such liquid crystals may be classified into positive liquid crystals having positive dielectric anisotropy and negative liquid crystals having negative dielectric anisotropy according to electrical characteristics. The liquid crystal molecules having positive dielectric anisotropy have long axes of liquid crystal molecules in a direction in which an electric field is applied. The liquid crystal molecules arranged in parallel and having negative dielectric anisotropy are arranged perpendicularly to the direction in which the electric field is applied and the long axis of the liquid crystal molecules.

Currently, active matrix LCDs (AM-LCDs) in which thin film transistors and pixel electrodes connected to the thin film transistors are arranged in a matrix manner have attracted the most attention due to their excellent resolution and video performance.

In general, the structure of a liquid crystal panel, which is a basic component of a liquid crystal display, will be described.

1 is a cross-sectional view showing a cross section of a general TN liquid crystal panel.

In the liquid crystal panel 20, two upper and lower panels 4 and 2 having various kinds of elements formed on the substrate 1 are attached to each other, and a liquid crystal layer between the two panels 2 and 4 is formed. 10) is fitted.

A first electrode connected to a thin film transistor corresponding to each pixel is generally referred to as a pixel electrode, and a second electrode corresponding to the pixel is commonly formed across a plurality of pixels.

The upper panel 4 includes a color filter layer 8 for implementing color and a common electrode 12 covering the color filter layer 8, and the common electrode 12 applies a voltage to the liquid crystal 10. It serves as one electrode. The lower panel 2 has a thin film transistor S serving as a switching function and a pixel electrode 14 serving as an electrode for receiving a signal from the thin film transistor S and applying a voltage to the liquid crystal 10. It is composed of

The portion where the pixel electrode 14 is formed is called the pixel portion P. FIG.

In addition, in order to prevent leakage of the liquid crystal 10 injected between the upper panel 4 and the lower panel 2, sealants may be formed at edges of the upper panel 4 and the lower panel 2. It is sealed with).

The liquid crystal display described above has a structure in which a common electrode is formed on a color filter panel which is an upper panel. That is, the liquid crystal display device having a structure in which the common electrode is perpendicular to the pixel electrode drives liquid crystal by an electric field applied up and down, and has excellent characteristics such as transmittance and aperture ratio, and the common electrode of the upper panel is grounded. It serves to prevent the destruction of the liquid crystal cell due to static electricity.

2A and 2B illustrate an operation of the liquid crystal 10 when voltage is applied to the twisted nematic liquid crystal panel, and FIG. 2A is a view showing an arrangement of liquid crystals of the TN liquid crystal panel when no voltage is applied. At this time, the liquid crystal 10 has a positive dielectric anisotropy (+), and has a horizontal arrangement state in which the upper and lower liquid crystals are twisted 90 ^° in plan view from the alignment direction.

FIG. 2B illustrates an arrangement of liquid crystal molecules when voltage is applied to upper and lower substrates. When voltage is applied to the upper and lower substrates, the liquid crystal molecules 10 twisted to 90 ^o are in the direction of an electric field. As a result, the extreme value of the liquid crystal molecules becomes approximately 90 °.

Therefore, there is a problem in that the change in C / R (contrast ratio) and luminance according to the viewing angle becomes severe, and thus the wide viewing angle cannot be realized.

FIG. 3 is a diagram illustrating a configuration of a liquid crystal display device in the IPS mode proposed to solve the problem of the viewing angle caused by the vertical electric field. The pixel electrode 34 and the common electrode 36 are the same on the substrate 30. It is formed on a plane. That is, the liquid crystal 10 is operated by the horizontal electric field 35 of the pixel electrode 34 and the common electrode 36 on the same substrate 1. The color filter panel 32 is formed on the liquid crystal layer 10.

4A and 4B illustrate a change in arrangement of liquid crystal molecules during voltage on / off in IPS mode. As shown in FIG. 4A, an electric field 35 is not applied to the pixel electrode 34 or the common electrode 36. It is shown that the change of the arrangement of the liquid crystal molecules does not occur in the state.

FIG. 4B illustrates a change in liquid crystal molecular arrangement when voltage is applied to the pixel electrode 34 and the common electrode 36. It can be seen that a transverse electric field 35 is formed.

5A and 5B are plan views showing molecular arrangements of liquid crystals according to whether an electric field is applied to the common electrode and the pixel electrode, and FIG. 5A shows a voltage difference between the common electrode 34 and the pixel electrode 35. When not applied, the alignment direction 41 of the liquid crystal molecules is arranged in the same direction as the alignment direction of the initial alignment layer (not shown).

FIG. 5B illustrates an arrangement direction 41a of liquid crystal molecules when a voltage is applied to the pixel electrode 35 and the common electrode 34. It is understood that the liquid crystal molecules are arranged in a direction 42 in which an electric field is applied. Can be.

The advantage of the IPS mode is that the wide field of view is possible because the change of the extreme value of each liquid crystal is small when the electric field is applied. That is, when the liquid crystal display device is viewed from the front, the liquid crystal display device may be visible at about 70 ° in the up / down / left / right directions.

FIG. 6 is a diagram illustrating characteristics of color coordinates according to viewing angles of the liquid crystal display of the IPS mode according to angles of 45 ^° and 135 ^° .

The IPS mode has the advantage of a wide viewing angle, but it can be seen that color shift occurs depending on the viewing angle in standard white light (0.329, 0.333). This is due to the birefringence characteristics of the liquid crystal, and published by S. Endow et al., "18.1-inch Diagonal Super-TFT-LCDs with wide viewing angle and fast response time of 20 ms" (Advanced 18.1-inch Diagonal Super-TFT-LCDs with Mega Wide Viewing Angle and Fast Response Speed of 20ms: IDW 99 ', p. 187) also point to this problem.

FIG. 7 is a diagram illustrating transmittance according to a viewing angle in each gray scale by dividing the gray scales of a general liquid crystal display into eight levels. When the gray scale of 0% transmittance is represented at the front, the viewing angles of the left and right sides are 60 ^o. It is understood that the transmittance is greater than that when expressing the fourth level of gray level in the region of about 25%.

In other words, one level of gray indicating the dark state indicates the dark state in front, but the left / right viewing angle is about 60 ^o. In this case, gray level inversion occurs, and gray level inversion corresponding to about four levels is generated and becomes a white state instead of a dark state.

Such a phenomenon is referred to as gray scale inversion, and this phenomenon is caused by the birefringence characteristic of the liquid crystal, and thus there is a problem in implementing a high-quality liquid crystal display device due to the inversion of transmittance between gray level.

In order to solve the problems of the conventional liquid crystal display of the TN mode and the liquid crystal display of the IPS mode as described above, an object of the present invention is to provide an excellent liquid crystal display with less color dependence and gray level inversion according to the viewing angle. .

In order to achieve the above object, in the present invention, the first and second substrates facing each other; A gate wiring extending in a first direction on the first substrate and a data wiring crossing the gate wiring and extending in a second direction; A thin film transistor formed at a portion where the gate line and the data line cross each other and receiving a signal from the gate and data line; A common wiring extending in the same direction as the gate wiring and receiving a first voltage; A plurality of common electrodes branched in the second direction in the common wiring; A plurality of pixel electrodes interposed between the common electrodes in the second direction and receiving a second voltage signal corresponding to the first voltage from the thin film transistor; A plurality of first dielectric protrusions formed on a substrate on which the plurality of common electrodes and pixel electrodes are formed; Provided is a liquid crystal display device comprising a liquid crystal positioned between the first and second substrates and having a different dielectric constant from the first dielectric protrusion.
The first dielectric protrusion is characterized by having a lower dielectric constant than the liquid crystal, and the first dielectric protrusion is characterized by having a higher dielectric constant than the liquid crystal.
In addition, the first dielectric protrusion is characterized in that the organic material, the organic material is characterized in that the material selected from the group consisting of photoresist, BCB, acrylic.
The first dielectric protrusion is positioned along a plurality of first virtual lines extending in the first direction on the pixel electrodes, and formed on the common electrodes and extending in the first direction. And a plurality of second dielectric protrusions positioned along the plurality of second virtual lines.
In addition, the liquid crystal is a positive liquid crystal having a positive dielectric anisotropy and the initial alignment direction is the second direction, the liquid crystal is a negative liquid crystal having a negative dielectric anisotropy and the initial alignment direction is the first liquid crystal It is characterized by one direction.
In another embodiment of the invention, the first and second substrates facing each other and corresponding; A gate wiring formed on the first substrate and extending in a first direction, and a data wiring crossing the gate wiring and extending in a second direction; A thin film transistor formed at a portion where the gate and the data line cross each other and receiving a signal from the gate and the data line; A common wiring extending in the same direction as the gate wiring and having a first common wiring auxiliary electrode and a second common wiring auxiliary electrode spaced apart from the first common wiring auxiliary electrode by a predetermined distance, respectively; A plurality of common electrodes vertically branched from the first and second common wiring auxiliary electrodes in a direction facing the first and second common wiring auxiliary electrodes; A plurality of pixel electrodes which receive signals from the thin film transistors and are alternately formed between the common electrodes; A plurality of first dielectric protrusions are disposed on a substrate on which the common electrode and the pixel electrode are formed. Provided is a liquid crystal display including liquid crystal positioned between the first and second substrates.
The first dielectric protrusion is characterized by having a lower dielectric constant than the liquid crystal, and the first dielectric protrusion is characterized by having a higher dielectric constant than the liquid crystal.
In addition, the first dielectric protrusion is characterized in that the organic material, the organic material is characterized in that the material selected from the group consisting of photoresist, BCB, acrylic.
The first dielectric protrusion is formed along a plurality of first virtual lines extending in a first direction on an upper portion of the pixel electrode, and is formed on an upper portion of each common electrode and extends in a first direction. And a plurality of second dielectric protrusions positioned along the second virtual line.
The liquid crystal is a positive liquid crystal having a positive dielectric anisotropy and an initial alignment direction is the first direction, wherein the liquid crystal is a negative liquid crystal having a negative dielectric anisotropy and an initial alignment direction is the second direction. It is characterized by that.
Hereinafter, a liquid crystal display according to the present invention will be described in detail with reference to the accompanying drawings.

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In general, the cause of the unevenness of brightness in the halftone in the liquid crystal display is due to the birefringence characteristic of the liquid crystal itself.

That is, the birefringence should be zero between the two polarizers in order to display the complete dark state in the liquid crystal display. However, since the liquid crystal itself is an optical system operating by birefringence, the value is opposite and the magnitude is corrected. Is to create a new system with the same birefringence.

To this end, the present invention uses a method of compensating birefringence of the liquid crystal by forming at least two domains having the same size and opposite directions in the same pixel area.

8A and 8B illustrate differences in birefringence according to a viewing angle of a general liquid crystal display and a liquid crystal display having two domains. In the case of a two domain liquid crystal display arranged in different directions, the birefringence value of one direction is shown. Since other domains compensate, the phenomenon of gray level inversion with the viewing angle is reduced.

That is, FIG. 8A is a diagram showing a cross section of a liquid crystal display having one domain, wherein the birefringence values at positions a, b, and c are different. Therefore, in the liquid crystal display having the domain shown in FIG. 8A, a deterioration in image quality characteristics inevitably occurs according to the viewing angle.

Figure 8b is a diagram showing the cross section of a liquid crystal display device forming the two domains in the pixel region, the second liquid-crystal birefringence value of a _first of the liquid crystal molecules will take a molecular arrangement in a direction opposite to the first liquid crystal molecules The birefringence value of a ₂ of the molecule is compensated (as a result, the birefringence value is about 0), so that the deterioration of the image quality according to the viewing angle is small.

As described above, the present invention provides a liquid crystal display having a multi domain by forming a plurality of dielectric protrusions 90 on each electrode in the liquid crystal display of the IPS mode.

First embodiment

In the first embodiment of the present invention, in order to form a multi-domain in the liquid crystal display of the IPS mode, the pixel electrodes 76 or the common electrodes 62 are alternately disposed, and a plurality of dielectric protrusions 90 are disposed on the positive electrodes. The present invention relates to a structure of a liquid crystal display device that forms multiple domains by forming an array and scattering an array of electric fields.

9 is a diagram illustrating a plane of the liquid crystal display according to the first exemplary embodiment of the present invention, wherein the pixel electrode 76 and the common electrode 62 are alternately formed.

Referring to the configuration of the liquid crystal display according to the first embodiment of the present invention shown in FIG. 9 in more detail, the gate wiring 50 and the common wiring 60 are arranged parallel to each other in the horizontal direction, and in the vertical direction The data line 70 is located.

The scan lines receive the on / off signals of the thin film transistors (not shown) through the gate lines 50, and receive the image signals for each frame through the data lines 70.
A gate electrode 52 and a source electrode 72 are formed on the gate line 50 and the data line 70 at the portion where the gate line 50 and the data line 70 cross each other, and the source electrode 72 is formed. ), A drain electrode 74 is formed.

On the other hand, the common wires 60 arranged in the horizontal direction are formed with a plurality of common electrodes 62 branched in the vertical direction. The common electrode 62 is formed in a direction in which the data line 70 extends.

In addition, the pixel electrode 76 is in contact with the drain electrode 74 and alternately with the common electrode 62 in a direction in which the common electrode 62 is branched.
The horizontal electric field is formed according to the voltages applied to the common electrode 62 and the pixel electrode 76, and the liquid crystal molecules between the horizontal electric fields are driven by the influence.

A plurality of dielectric protrusions 90 are formed on the pixel electrode 76 and the common electrode 62. As the dielectric protrusion 90, a material having a dielectric constant smaller than that of a liquid crystal (not shown) is used. Preferably, a material having a dielectric constant of about 5 or less is used.

As described above, the electric field generated in the vicinity of the dielectric protrusion 90 having a relatively smaller dielectric constant than the liquid crystal is much thinner than the electric field generated in the portion where only the liquid crystal is present.

In other words, since the dielectric protrusion 90 has a relatively low dielectric constant compared to the liquid crystal, the affinity with the electric field is smaller than that of the liquid crystal, so that the arrangement of the electric field is constant at a predetermined angle around the dielectric protrusion 90. The process proceeds from the common electrode (or pixel electrode) to the pixel electrode (or common electrode).

Here, the dielectric protrusions 90 are alternately formed between the pixel electrode 76 and the common electrode 62, and are formed on the top of each electrode in an extending direction, for example, each pixel electrode 76 is simultaneously formed. When the dielectric protrusion 90 is formed on the first virtual line C1 that crosses the dielectric protrusion 90, the dielectric protrusion 90 is formed on the second virtual line C2 that simultaneously crosses each common electrode 62. It is formed between the first and second virtual lines (C ₁ , C ₂ ).

FIG. 10 is an enlarged view of a portion Z of FIG. 9, and illustrates an electric field formed between the common electrode 62 and the pixel electrode 76 and a molecular arrangement direction of the liquid crystal 80 according to the electric field in detail.

Here, a fringe field is formed in which electric fields applied to the upper and lower portions of the dielectric protrusion 90 formed on the pixel electrode 76 are displaced in opposite directions.

In other words, the electric field applied between the common electrode 62 formed on both sides of the pixel electrode 76 and the pixel electrode 76 with the pixel electrode 76 interposed therebetween is the pixel electrode 76. The dielectric protrusion 90 formed on the upper portion bypasses the dielectric protrusion 90 and faces the pixel electrode 76.

Accordingly, the liquid crystals 80 positioned above and below the dielectric protrusion 90 are formed with first and second domains arranged in different directions according to the application of an electric field.

The reason why the liquid crystals 80 are arranged in opposite directions with respect to the dielectric protrusion 90 as described above is that the degree of freedom of the liquid crystals 80 becomes two.

That is, as shown in FIG. 11, if the molecular arrangement direction (that is, the alignment direction) of the initial liquid crystal 80 is the same direction as the extending direction of the pixel electrode 76 and the common electrode 62, the liquid crystal Since the degrees of freedom are 2, they are arranged left / right. At this time, the force causing the liquid crystal 80 to be arranged left / right is due to the electric field disturbed by the dielectric protrusion 90, and two different domains are formed by the electric field.

In other words, the liquid crystal 80 in which the initial arrangement direction is parallel to the pixel electrode 76 and the common electrode 62 is rearranged horizontally in the direction of the electric field when an electric field is applied. The rotation direction of the liquid crystal 80 rotates in a direction in which the angle formed with the electric field is small.

Accordingly, since the angles formed between the electric field and the initial arrangement direction of the liquid crystal 80 are different based on the dielectric protrusion 90, different domains are formed.

On the other hand, the positive characteristic of the liquid crystal 80 used in the first embodiment of the present invention is a positive liquid crystal having a positive dielectric anisotropy, the molecular alignment direction of the initial liquid crystal 80 The determining direction is determined in the same direction (ie, vertical direction) as the direction in which the common electrode 62 and the pixel electrode 76 extend.

In addition, when the liquid crystal 80 is initially oriented in a direction perpendicular to the direction in which the common electrode 62 and the pixel electrode 76 extend (that is, the horizontal direction), a liquid crystal having a negative dielectric anisotropy may be used. .

By forming the liquid crystal display device as described above, in the conventional IPS mode liquid crystal display device operating in the birefringence mode, the dependence of the wavelength according to the viewing angle is strong, but in the first embodiment of the present invention in two different directions in the plane The two moving domains compensate each other for color characteristics according to the viewing angle, thereby reducing gradation inversion according to the viewing angle.

FIG. 12 is a cross-sectional view taken along the cut line XII-XII of FIG. 10, and it can be seen that the dielectric protrusion 90 is formed on the pixel electrode 76.

Here, the dielectric protrusion 90 is a material having a lower dielectric constant than the liquid crystal 80, and mainly, an organic material such as photoresist, BCB (benzocyclobutene), acrylic (acryl) is used, the dielectric protrusion 90 is in direct contact with the liquid crystal 80.

Meanwhile, the pixel electrode 76 and the common electrode 62 are insulated by the gate insulating film 3, and the pixel electrode 76 is covered with the protective film 5.

The dielectric protrusion 90 may function as a spacer for maintaining cell gaps of the upper and lower substrates 1.

In the above-described first embodiment of the present invention, the dielectric protrusion 90 has been described above on each electrode (pixel electrode and common electrode), but other than the pixel electrode 76 and the common electrode 62. Even if the dielectric protrusion 90 is formed on the portion of the dielectric projection 90, the same function as that of the liquid crystal display device as in the first embodiment may be performed, and detailed drawings thereof will be omitted.

Second embodiment

Compared to the formation of the common electrode and the pixel electrode in the vertical direction in the first embodiment, the liquid crystal display device of the IPS mode according to the second embodiment of the present invention is to form the positions of the common electrode and the pixel electrode in the horizontal direction. It is about.

FIG. 13 is a diagram illustrating a plane of a liquid crystal display device in an IPS mode according to a second embodiment of the present invention, in which a gate line 50 is formed in a horizontal direction, and a data line 70 is formed in a vertical direction.

In addition, a common wiring 60 is formed in parallel with the gate wiring 50, and a first common wiring auxiliary electrode 64a is vertically branched on the common wiring 60, and the first common wiring auxiliary is formed. The second common wiring auxiliary electrode 64b is formed to be spaced apart from the electrode 64a by a predetermined interval and vertically branched from the common wiring 60.

The first and second common wiring auxiliary electrodes 64a and 64b are divided between the first and second common wiring auxiliary electrodes 64a and 64b in the direction in which the auxiliary electrodes 64a and 64b face each other. A plurality of common electrodes 62 are formed, that is, the common electrodes 62 substantially affecting the molecular arrangement by applying an electric field to the liquid crystal in a direction in which the gate wiring 50 extends (ie, in a horizontal direction). Is formed.

A thin film transistor S is formed as a switching element at a portion where the data line 70 and the gate line 50 cross each other, and the pixel electrode 76 contacting the thin film transistor S is the common electrode 62. ) Are staggered from each other in the direction in which they are formed.

As described above, the liquid crystal display according to the second exemplary embodiment of the present invention has a pixel electrode 76 and a common electrode which substantially affect the molecular arrangement of the liquid crystal as compared to the liquid crystal display described in the first exemplary embodiment. The arrangement position of 62) is different.

That is, in the first embodiment of the present invention, the pixel electrode 76 and the common electrode 62 are formed in the direction in which the data line 70 extends. In the second embodiment of the present invention, the pixel electrode 76 is formed. ) And the common electrode 62 are formed in a direction in which the gate wiring 50 extends.

On the other hand, in the liquid crystal display according to the second embodiment of the present invention, if the alignment direction for determining the initial arrangement direction of the liquid crystal molecules is a direction in which the pixel electrode 76 and the common electrode 62 extend, positive dielectric anisotropy is positive (+). A negative liquid crystal having a dielectric anisotropy is used if the alignment direction is perpendicular to the direction in which the pixel electrode 76 and the common electrode 62 extend.

The liquid crystal display according to the second exemplary embodiment of the present invention uses an electric field distorted by the dielectric protrusion 90 existing on the pixel electrode and the common electrode 76, 62. Since it is the same as in the first embodiment, detailed description thereof will be omitted.

Here, in the liquid crystal display according to the second exemplary embodiment of the present invention, a structure in which the dielectric protrusion 90 is formed only on the pixel electrode and the common electrodes 76 and 62 has been described. It may be formed on portions other than the pixel electrodes and the common electrodes 76 and 62, and detailed drawings thereof will be omitted.

As described above, the present invention, as described in detail in each embodiment, the basic concept is that the conventional IPS mode liquid crystal display device in the multi-domain in the liquid crystal to improve the poor quality of the image according to the viewing angle, such as color shift and gradation inversion depending on the viewing angle To make each domain compensate for image quality.

To this end, each embodiment of the present invention uses a method of disturbing the arrangement of the electric field applied to each electrode by forming a dielectric projection smaller than the liquid crystal on the pixel electrode 76 or the common electrode 62, respectively.

As described above, when the direction of the electric field is distorted by changing the pixel electrode 76 and the common electrode 62, at least two domains arranged in different directions are formed according to the application of the electric field. By compensating the birefringence of the light, there is an advantage that can improve the degradation of the image quality according to the viewing angle.

In the first and second embodiments described above, the structure in which the dielectric protrusions 90 are formed on both the common electrode 62 and the pixel electrode 76 is disclosed. It will be clearly understood that the dielectric protrusion 90 formed only on one of the electrodes has the same effect as the liquid crystal display device shown in the first and second embodiments.

In addition, in the above-described first and second embodiments, the dielectric protrusion 90 has a smaller dielectric constant than the liquid crystal. However, even when the dielectric protrusion 90 uses a material having a higher dielectric constant than the liquid crystal, multiple domains are formed. The molecular arrangement direction of the liquid crystal will be opposite to that of the first embodiment described above.

In other words, if the dielectric protrusion 90 is formed of a material having a different dielectric constant from the liquid crystal, there is no problem in forming multiple domains.

Meanwhile, in the above-described exemplary embodiment, the structure in which the dielectric protrusion 90 is formed on the pixel electrode 76 and the common electrode 62 has been described, but the pixel electrode 76 and Even if the dielectric protrusions 90 are formed at portions other than the common electrode 62, the liquid crystal display device having the same function as the liquid crystal display device of the first and second embodiments of the present invention can be configured. It will be clearly understood through.

As described above, the liquid crystal display according to the exemplary embodiments of the present invention has the following characteristics.

First, in the liquid crystal display of the conventional IPS mode, the liquid crystal molecules are rotated in one direction in a plane, so that the color inversion according to the viewing angle exists, but the liquid crystal display according to the present invention rotates in at least two different opposite directions. As the domain is formed, there is an advantage of improving the characteristics of color inversion according to the viewing angle.

Second, there is an advantage that can improve the characteristics of grayscale inversion according to the viewing angle by the two domains that rotate in different directions.

Claims (20)

First and second substrates facing each other; A gate wiring extending in a first direction on the first substrate and a data wiring crossing the gate wiring and extending in a second direction; A thin film transistor formed at a portion where the gate line and the data line cross each other and receiving a signal from the gate and data line; A common wiring extending in the same direction as the gate wiring and receiving a first voltage; A plurality of common electrodes branched in the second direction in the common wiring; A plurality of pixel electrodes interposed between the common electrodes in the second direction and receiving a second voltage signal corresponding to the first voltage from the thin film transistor; A plurality of first dielectric protrusions formed on a substrate on which the plurality of common electrodes and pixel electrodes are formed; A liquid crystal positioned between the first and second substrates and having a different dielectric constant from the first dielectric protrusion Liquid crystal display comprising a. The method according to claim 1, And the first dielectric protrusion has a lower dielectric constant than the liquid crystal. The method according to claim 1, And the first dielectric protrusion has a higher dielectric constant than the liquid crystal. The method according to claim 1, The first dielectric protrusion is an organic material. The method according to claim 4, The organic material is a liquid crystal display device selected from the group consisting of photoresist, BCB, acrylic. The method according to claim 1, And the first dielectric protrusion is positioned along a plurality of first virtual lines extending in the first direction on the pixel electrodes. The method according to claim 6, And a plurality of second dielectric protrusions formed on the common electrodes and positioned along a plurality of second virtual lines extending in a first direction. delete The method according to claim 1, And the liquid crystal is a positive liquid crystal having a positive dielectric anisotropy and an initial alignment direction is the second direction. The method according to claim 1, Wherein the liquid crystal is a negative liquid crystal in which dielectric anisotropy is negative and the initial alignment direction is the first direction. First and second substrates facing each other; A gate wiring formed on the first substrate and extending in a first direction, and a data wiring crossing the gate wiring and extending in a second direction; A thin film transistor formed at a portion where the gate and the data line cross each other and receiving a signal from the gate and the data line; A common wiring extending in the same direction as the gate wiring and having a first common wiring auxiliary electrode and a second common wiring auxiliary electrode spaced apart from the first common wiring auxiliary electrode by a predetermined distance, respectively; A plurality of common electrodes vertically branched from the first and second common wiring auxiliary electrodes in a direction facing the first and second common wiring auxiliary electrodes; A plurality of pixel electrodes which receive signals from the thin film transistors and are alternately formed between the common electrodes; A plurality of first dielectric protrusions on the substrate on which the common electrode and the pixel electrode are formed; Liquid crystal positioned between the first and second substrates Liquid crystal display comprising a. The method according to claim 11, And the first dielectric protrusion has a lower dielectric constant than the liquid crystal. The method according to claim 11, And the first dielectric protrusion has a higher dielectric constant than the liquid crystal. The method according to claim 11, The first dielectric protrusion is an organic material. The method according to claim 14, The organic material is a liquid crystal display device selected from the group consisting of photoresist, BCB, acrylic. The method according to claim 11, And the first dielectric protrusion is formed along a plurality of first virtual lines extending in a first direction on the pixel electrode. The method according to claim 16, And a plurality of second dielectric protrusions formed on the common electrodes and positioned along a plurality of second virtual lines extending in a first direction. delete The method according to claim 11, Wherein the liquid crystal is a positive liquid crystal having a positive dielectric anisotropy and an initial alignment direction is the first direction. The method according to claim 11, Wherein the liquid crystal is a negative liquid crystal in which dielectric anisotropy is negative and the initial alignment direction is the second direction.

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