KR100853778B1 - Multi-domain liquid crystal display device - Google Patents

Abstract

The present invention relates to a multi-domain liquid crystal display device for effectively distorting an electric field to realize a stable texture, comprising: a plurality of gate lines and data lines formed vertically and horizontally on a first substrate to define a pixel region; A pixel electrode formed in the pixel region of the first substrate; A first dielectric structure formed under the pixel electrode; A color filter layer formed on the second substrate; A plurality of second dielectric structures formed to have an inclined surface on the color filter layer; A common electrode formed on an entire surface of the color filter layer including the second dielectric structure; It comprises a liquid crystal layer formed between the first substrate and the second substrate.

Dielectric Structure, Common Electrode

Description

Multi domain Liquid Crystal Display Device

1 is a schematic cross-sectional view of a conventional liquid crystal display device

2 is a plan view illustrating unit pixels of a multi-domain liquid crystal display device according to a first exemplary embodiment of the present invention.

3A and 3B are cross-sectional views taken along line A-A 'and B-B' of FIG. 2, respectively.

4 is a view for explaining the electric field of the present invention

5 is a plan view illustrating unit pixels of a multi-domain liquid crystal display according to a second exemplary embodiment of the present invention.

6A and 6B are cross sectional views taken along the line A-A 'and B-B' of FIG. 5, respectively.

7 is a plan view illustrating unit pixels of a multi-domain liquid crystal display device according to a third exemplary embodiment of the present invention.

8A through 8B are cross-sectional views taken along line A-A 'and B-B' of FIG. 7, respectively.

<Description of main parts of drawing>

10: first substrate 12: gate insulating film

13 pixel electrode 14 protective film

15: electric field induction window 16: gate wiring

18: data wiring 20: second substrate                 

22: light shielding layer 24: color filter layer

26: common electrode 28, 28a: dielectric structure

The present invention relates to a liquid crystal display device, and more particularly, to a multi-domain liquid crystal display device capable of stably distorting an electric field.

In general, a liquid crystal display device is composed of a lower substrate and an upper substrate facing each other at predetermined intervals, and a liquid crystal layer formed between the substrates.

Among the liquid crystal display devices, the vertical alignment mode liquid crystal display device uses a negative liquid crystal having a negative dielectric anisotropy. In a state where no voltage is applied, the long axis direction of the liquid crystal molecules is perpendicular to the alignment layer plane. When the voltage is applied, the liquid crystal molecules are oriented obliquely by the electric field. That is, an image is displayed by adjusting the transmittance of light by using the property oriented by an electric field.

Meanwhile, in the vertical alignment mode, in order to realize a wide viewing angle, an auxiliary electrode, a rib, or a slit is formed on a substrate to distort the electric field applied to the liquid crystal layer, thereby directing the director of the liquid crystal molecules in a desired direction. Positioning methods are proposed, for example, patterned vertical alignment (PVA), multi-domain vertical alignment (MVA), and the like. Hereinafter, a conventional liquid crystal display device will be described with reference to the accompanying drawings.

1 is a cross-sectional view of a unit pixel of a conventional liquid crystal display device for driving liquid crystal by an auxiliary electrode, wherein the conventional liquid crystal display device includes a first substrate and a second substrate (not shown); A plurality of gate wires and data wires (not shown) formed vertically and horizontally on the first substrate to define pixel regions; A thin film transistor (not shown) formed in the pixel region and composed of a gate electrode, a gate insulating film, a semiconductor layer, an ohmic contact layer, and a source / drain electrode; A pixel electrode (1) connected to the thin film transistor and formed in the pixel region; A protective film 3 formed under the pixel electrode 1; A light blocking layer (not shown) formed on the second substrate to block light leaking from the gate wiring, the data wiring, and the thin film transistor; A color filter layer 4 formed on the light blocking layer; A common electrode 5 formed on the color filter layer 4; A dielectric structure 6 formed on the common electrode 5; And a liquid crystal layer (not shown) formed between the first substrate and the second substrate. The conventional liquid crystal display device distorts the electric field applied to the liquid crystal layer by the action of the pixel electrode 1 and the dielectric structure 6. Therefore, the dielectric energy is positioned in the desired direction by the distorted electric field, thereby driving the liquid crystal molecules in the unit pixel in various ways to implement a multi-domain effect.

However, since the electric field is distorted due to the difference between the dielectric constant of the dielectric structure 6 and the dielectric anisotropy of the liquid crystal, the conventional liquid crystal display device should be formed in consideration of the dielectric constant of the dielectric structure 6 according to the liquid crystal for effective electric field distortion. The problem arises.

In addition, in the liquid crystal display device, the field distortion near the region where the dielectric structure 6 is formed is unstable, thus making it difficult to obtain a stable texture and causing an afterimage.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a multi-domain liquid crystal display device capable of effectively distorting an electric field irrespective of dielectric constant of a dielectric structure.

Another object of the present invention is to provide a multi-domain liquid crystal display device having a stable texture and no afterimage by improving electric field distortion near the dielectric structure.

The present invention for achieving the above object is a first substrate and a second substrate; A plurality of gate lines and data lines formed vertically and horizontally on the first substrate to define pixel regions; A pixel electrode formed in the pixel region of the first substrate; A first dielectric structure formed under the pixel electrode; A color filter layer formed on the second substrate; A plurality of second dielectric structures formed to have an inclined surface on the color filter layer; A common electrode formed on an entire surface of the color filter layer including the second dielectric structure; It comprises a liquid crystal layer formed between the first substrate and the second substrate. According to the present invention having the above structure, the common electrode is formed to have an inclined surface by using a dielectric structure. As a result, since the electric field adjacent to the common electrode is formed in a direction perpendicular to the equipotential curve formed along the inclined plane, stable electric field distortion can be induced.

Further, in order to improve the response speed, an electric field induction window may be formed on the pixel electrode, or the pixel electrode may be formed to have an inclined surface like the common electrode.                     

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

First embodiment

FIG. 2 is a plan view of a unit pixel of a multi-domain liquid crystal display device according to a first exemplary embodiment of the present invention, FIG. 3A is a cross-sectional view taken along the line AA ′ of FIG. 2, and FIG. 3B is a cross-sectional view taken along the line B-B ′ of FIG. 2.

A first embodiment of the present invention includes a first substrate 10 and a second substrate 20; A plurality of gate wirings 16 and data wirings 18 formed on the first substrate 10 in a lengthwise and horizontal direction to define pixel regions; A gate insulating film 12 formed on the gate wiring 16 and the first substrate 10; A protective film 14 formed on the data wiring 18 and the gate insulating film 12; A pixel electrode 13 formed on the passivation layer 14 in the pixel region; A thin film transistor (not shown) formed at an intersection point of the gate line 16 and the data line 18; A light blocking layer 22 formed in a predetermined region on the second substrate 20 to prevent light leakage generated in the region in which the gate wiring 16, the data wiring 18, and the thin film transistor are formed; A color filter layer 24 formed on a predetermined portion of the light blocking layer 22 and on the second substrate 20; A plurality of dielectric structures 28 formed to have an inclined surface on the color filter layer 24; A common electrode 26 formed on a front surface of the dielectric structure 28; And a liquid crystal layer (not shown) formed between the first substrate 10 and the second substrate 20. The pixel electrode 13 may be made of indium tin oxide (ITO) or indium zinc oxide (IZO), and the common electrode 26 may be made of ITO.                     

The dielectric structure 28 is preferably formed of acrylic resin (photoacrylate), BCB (BenzoCycloButene) or novolac resin, or may be formed of a photosensitive material.

The liquid crystal is a liquid crystal having a negative dielectric anisotropy, and a chiral dopant is preferably included in the VA (Vertical Alignment) liquid crystal so that molecular alignment and optical axis of the liquid crystal are continuously formed by applying an electric field.

The passivation layer 14 may be formed of a material such as BCB (BenzoCycloButene), an acrylic resin, a polyamide compound, SiNx, or SiOx, and the gate insulating layer 12 may be formed of the passivation layer 14. It may be formed of the same material as), but preferably formed of SiNx or SiOx.

In addition, the gate wiring 16, the data wiring 18, the color filter layer 24, etc. may be formed by changing the range within the range which can be easily implemented by those skilled in the art having ordinary skill in the art. have.

Although not shown in the drawings, the thin film transistor includes a gate electrode, a source electrode, and a drain electrode connected to the gate wiring 16, the data wiring 18, and the pixel electrode 13, respectively. do.

In addition, an auxiliary electrode (not shown) electrically connected to the common electrode 26 may be further formed under the pixel electrode 13 to efficiently drive the liquid crystal at the domain boundary.

Here, the auxiliary electrode is preferably made of any one material selected from the group consisting of indium tin oxide (ITO), Al, Mo, Cr, Ta, Ti, and Al alloy.

In addition, an alignment layer may be formed on an entire surface of at least one of the first substrate 10 and the second substrate 20. The alignment layer may be formed of a material such as polyamide or polyimide compound, PVA (polyvinylalcohol), polyamic acid, or the like, and may be formed without rubbing alignment or alignment treatment. have. In addition, it may be formed by using a photoreactive material such as polyvinylcinnamate (PVCN), polysiloxanecinnamate (PSCN), or cellulosecinnamate (CelCN) -based compound.

In addition, a retardation film may be formed on an outer surface of at least one of the first substrate 10 and the second substrate 20. The retardation film compensates the viewing angle in the direction perpendicular to the substrate and the direction of the viewing angle change, thereby widening the area without gray inversion, and increasing the contrast ratio in the oblique direction. The film may be formed as a negative uniaxial film or a negative biaxial film having two optical axes, but a negative biaxial film is more preferable in terms of a wide viewing angle. The first and second substrates 10, 20) a polarizer (not shown) is attached, the polarizer may be formed integrally with the retardation film.

The liquid crystal display according to the first exemplary embodiment of the present invention configured as described above forms a dielectric structure 28 having an inclined surface on the color filter layer 24 and covers the dielectric structure 28. The common electrode 26 is formed on the substrate to effectively distort the electric field.

As shown in FIG. 4, the common electrode 26 formed on the dielectric structure 28 has a slope by the dielectric structure 28, and an equipotential curve is formed along the slope of the common electrode 26. Is formed. Here, the electric field adjacent to the common electrode 26 is formed in a direction perpendicular to the equipotential curve, leading to stable electric field distortion. Thus, such a structure not only needs to consider the dielectric constants of the dielectric structure and the liquid crystal for electric field distortion, but also greatly improves unstable field distortion in the region adjacent to the dielectric structure 28.

Second embodiment

FIG. 5 is a plan view of a unit pixel of a multi-domain liquid crystal display according to a second exemplary embodiment of the present invention, FIG. 6A is a cross-sectional view taken along the line AA ′ of FIG. 5, and FIG. 6B is a line BB ′ of FIG. 5. It is a cross section of.

A second embodiment of the present invention includes a first substrate 10 and a second substrate 20; A plurality of gate wirings 16 and data wirings 18 formed on the first substrate 10 in a lengthwise and horizontal direction to define pixel regions; A gate insulating film 12 formed on an entire surface of the first substrate 10 including the gate wiring 16; A protective film 14 formed over the gate insulating film 12 including the data wiring 18; A pixel electrode 13 formed on the passivation layer 14 in the pixel region and having an electric field induction window 15 formed therein so as to divide the pixel region into a plurality of domains; A thin film transistor (not shown) formed at an intersection point of the gate line 16 and the data line 18; A light blocking layer 22 formed in a predetermined region on the second substrate 20 to prevent light leakage generated in the region in which the gate wiring 16, the data wiring 18, and the thin film transistor are formed; A color filter layer 24 formed on the light blocking layer 22; A plurality of dielectric structures (28) formed on the color filter layer (24) with inclined surfaces and formed in each of the plurality of domain regions divided by the field induction window (15); A common electrode 26 formed on a front surface of the dielectric structure 28; And a liquid crystal layer (not shown) formed between the first substrate 10 and the second substrate 20. That is, the liquid crystal display according to the second exemplary embodiment of the present invention includes a pixel electrode 13 having various types of electric field induction windows 15 for domain division, and a dielectric structure 28 formed in a semicircle in each of the divided domains. And a common electrode 26 formed to cover the dielectric structure 28 to induce electric field distortion by an inclined surface. The field induction window 15 may be formed as a hole by patterning the gate insulating layer 12 and / or the protective layer 14.

Third embodiment

FIG. 7 is a plan view illustrating various types of unit pixels of a multi-domain liquid crystal display according to a third exemplary embodiment of the present invention, FIG. 8A is a cross-sectional view taken along a line A-A 'of FIG. 7, and FIG. 8B is a B- line of FIG. 7. Sectional view of line B '.

A third embodiment of the present invention includes a first substrate 10 and a second substrate 20; A plurality of gate wirings 16 and data wirings 18 formed on the first substrate 10 in a lengthwise and horizontal direction to define pixel regions; A gate insulating film 12 formed on the gate wiring 16 and the first substrate 10; A protective film 14 formed on the data wiring 18 and the gate insulating film 12; At least one first dielectric structure 28a formed on the passivation layer 14 to have an inclined surface; A pixel electrode 13 formed on the first dielectric structure 28a and the passivation layer 14 in the pixel region; A thin film transistor (not shown) formed at an intersection point of the gate line 16 and the data line 18; A light blocking layer 22 formed in a predetermined region on the second substrate 20 to prevent light leakage generated in the region in which the gate wiring 16, the data wiring 18, and the thin film transistor are formed; A color filter layer 24 formed on a predetermined portion of the light blocking layer 22 and on the second substrate 20; A plurality of second dielectric structures 28 formed to have an inclined surface on the color filter layer 24; A common electrode 26 formed on a front surface of the second dielectric structure 28; And a liquid crystal layer (not shown) formed between the first substrate 10 and the second substrate 20. That is, the liquid crystal display device according to the third embodiment of the present invention includes a semicircular first dielectric structure 28a formed on the protective layer 14 and a protective layer 14 including the first dielectric structure 28a. The pixel electrode 13 formed on the front surface, the second dielectric structure 28 formed to have an inclined surface on the color filter layer 24, and the color filter layer 24 formed to cover the second dielectric structure 28. It characterized in that it comprises a common electrode (26).

Here, the first dielectric structure 28a is formed at a position opposite the intermediate point between the second dielectric structures 28. Therefore, the electric field in the region adjacent to the second dielectric structure 28 as well as the electric field in the region adjacent to the first dielectric structure 28a are distorted, thereby achieving stable texture and improving response speed.                     

The present invention is not limited to the above embodiments, but is within the range that can be modified by those skilled in the art within the scope of the technical idea of the present invention.

In the multi-domain liquid crystal display device according to the present invention having the above configuration, by forming a common electrode having an inclined surface on the dielectric structure, the electric field can be effectively distorted regardless of the dielectric constant difference between the liquid crystal and the dielectric structure. Therefore, the efficiency of a manufacturing process can be improved.

In addition, by improving the electric field distortion in the vicinity of the dielectric structure it is possible to implement a stable texture and solve the afterimage problem.

Claims (9)

A first substrate and a second substrate; A plurality of gate lines and data lines formed vertically and horizontally on the first substrate to define pixel regions; A pixel electrode formed in the pixel region of the first substrate; A first dielectric structure formed under the pixel electrode; A color filter layer formed on the second substrate; A plurality of second dielectric structures formed to have an inclined surface on the color filter layer; A common electrode formed on an entire surface of the color filter layer including the second dielectric structure; And a liquid crystal layer formed between the first substrate and the second substrate. The method of claim 1, And the pixel electrode further comprises an electric field induction window for dividing the pixel region into a plurality of domains. delete The multi-domain liquid crystal display of claim 1, wherein the liquid crystal layer is formed of a vertical alignment liquid crystal. The method of claim 1, And a thin film transistor formed at an intersection point of the gate line and the data line. The method of claim 1, The first and second dielectric structures are made of any one of acrylic resin (photoacrylate), BCB (BenzoCycloButene), novolac resin (novolac) resin. The method of claim 1, And a retardation film formed on at least one of the first substrate and the second substrate. The method of claim 1, And an auxiliary electrode electrically connected to the common electrode and formed under the pixel electrode. The method of claim 1, And the first dielectric structure is formed at a position opposite to an intermediate point between the second dielectric structures.

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