KR20040001621A - Multi domain Liquid Crystal Display Device - Google Patents

Abstract

PURPOSE: A multi-domain liquid crystal display is provided to improve a contrast ratio by interrupting light from leaking at a dielectric structure formed area by forming a second shielding layer on the dielectric structure. CONSTITUTION: A first substrate and a second substrate are provided. A plurality of gate lines(16) and data lines(18) are formed on the first substrate for defining pixel areas. A thin film transistor is formed at every cross point of the gate lines and the data lines. Pixel electrode(20) are connected with the thin film transistors and are formed in the pixel areas. A shielding layer is formed of a first shielding layer is formed on the second substrate and at an area corresponding to the gate lines, the data lines, and the thin film transistors, and a second shielding layer formed at the pixel areas. A color filter layer is formed on the shielding layer. A common electrode is formed on the color filter layer. A dielectric structure(38) is formed on the common electrode and at an upper area of the shielding layer. A liquid crystal layer is formed between the first substrate and the second substrate.

Description

Multi domain Liquid Crystal Display Device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device that realizes a multi-domain effect by driving various liquid crystals by 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 a predetermined interval, 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 in a direction perpendicular to the direction of the electric field to adjust the transmittance of light to display an image.

Meanwhile, in order to implement a wide viewing angle in the vertical alignment mode, a method of implementing a multi-domain effect by distorting an electric field applied to a liquid crystal layer by forming an auxiliary electrode, a rib, or a slit on a substrate (for example, , PVA (Patterned Vertical Alignment), and MVA (Multi-domain Vertical Alignment) have been proposed. Hereinafter, a display device of a conventional liquid crystal will be described with reference to the drawings.

1 is a cross-sectional view of a unit pixel of a conventional liquid crystal display device in which an electric field is distorted by using a protrusion Rib. The conventional liquid crystal display device includes a first substrate 1 and a second substrate 2; A plurality of gate lines and data lines (not shown) formed vertically and horizontally on the first substrate 1 to define pixel regions; A thin film transistor (not shown) formed at an intersection point of the gate line and the data line; A pixel electrode 3 connected to the thin film transistor and formed in the pixel region; A light blocking layer (4) formed on the second substrate (2) to block light leaking from the gate wiring, the data wiring, and the thin film transistor; A color filter layer 6 formed on the light shielding layer 4; A common electrode 8 formed on the color filter layer 6; A protrusion Rib 9 formed on the common electrode 8; And a liquid crystal layer 5 formed between the first substrate 1 and the second substrate 2.

In the conventional liquid crystal display device, the electric field (dashed line in FIG. 1) is distorted by the protrusions 9 formed on the common electrode 8, and the molecules of the liquid crystal 5 are arranged in a direction perpendicular to the direction of the distorted electric field. Therefore, the multi-domain effect is implemented to have a wide viewing angle.

However, in the conventional liquid crystal display device, a light leakage phenomenon occurs in a region where the protrusions 9 are formed, resulting in a problem of lowering contrast ratio characteristics.

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 in which light leakage phenomenon is prevented.

Another object of the present invention is to provide a multi-domain liquid crystal display device having a wide viewing angle through effective field distortion.

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

FIG. 2A 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, and FIG. 2B is a cross-sectional view taken along the line AA ′ of FIG. 2A.

3A 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, and FIGS. 3B and 3C are cross-sectional views of various shapes of the AA ′ line of FIG. 3A, respectively.

4A is a plan view of a unit pixel of a multi-domain liquid crystal display according to a third exemplary embodiment of the present invention, and FIG. 4B is a cross-sectional view taken along the line BB ′ of FIG. 4A.

5 is a plan view of a unit pixel of a multi-domain liquid crystal display device according to a fourth exemplary embodiment of the present invention.

<Description of Signs of Major Parts of Drawing>

10: first substrate 30: second substrate

12 gate insulating film 14 protective film

16: gate wiring 18: data wiring

20: pixel electrode 25: electric field induction window

32a: first light blocking layer 32b: second light blocking layer

34: color filter layer 36: common electrode

38 dielectric structure 40 auxiliary electrode

The present invention to achieve the above object, the first substrate and the second substrate; A plurality of gate wirings and data wirings formed vertically and horizontally on the first substrate to define pixel regions; A thin film transistor formed at an intersection point of the gate line and the data line; A pixel electrode connected to the thin film transistor and formed in the pixel area; A light blocking layer formed on the second substrate and including a first light blocking layer formed in a region corresponding to the gate wiring, a data wiring, and a thin film transistor, and a second light blocking layer formed in the pixel region; A color filter layer formed on the light blocking layer; A common electrode formed on the color filter layer; A dielectric structure formed on the common electrode and formed in an area above the second light blocking layer; And it provides a multi-domain liquid crystal display device comprising a liquid crystal layer formed between the first substrate and the second substrate.

That is, the multi-domain liquid crystal display device according to the present invention is to prevent the leakage of light in the dielectric structure formation region by forming a second light shielding layer on the dielectric structure formed to distort the electric field.

In addition, in the multi-domain liquid crystal display according to the present invention, an auxiliary electrode may be further formed to surround the pixel electrode in order to more stably distort the electric field around the pixel electrode.

In addition, the multi-domain liquid crystal display device according to the present invention can implement a wide viewing angle effect by dividing a plurality of domains by forming an electric field induction window inside the pixel electrode.

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

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

As shown in FIG. 2A and FIG. 2B, gate wirings 16 and data wirings 18 are formed on the first substrate 10 in a vertical and horizontal direction to define pixel regions, and include the gate wirings 16. A gate insulating film 12 is formed on the entire surface of the substrate, a protective film 14 is formed on the entire surface of the substrate including the data line 18, and a pixel electrode 20 is formed on the protective film 14.

The gate insulating layer 12 and the protective layer 14 may be formed of a material such as SiNx, SiOx, BCB (BenzoCycloButene), acrylic resin, polyamide compound, or the like.

Although not shown, the intersection of the gate wiring 16 and the data wiring 18 includes a gate electrode, a source / drain electrode formed to face each other, and a semiconductor layer interposed between the gate electrode and the source / drain electrode. A thin film transistor is formed.

In this case, the gate electrode is connected to the gate line 16, the source electrode is connected to the data line 18, and the drain electrode is connected to the pixel electrode 20.

On the second substrate 30, a first light blocking layer 32a is formed in a region corresponding to the gate wiring 16, the data wiring 18, and a thin film transistor region, and a second light blocking layer in the pixel region. 32b is formed.

In this case, the first light blocking layer 32a and the second light blocking layer 32b may be formed of the same material or different materials.

A red, green, and red color filter layer 34 is formed on the light blocking layers 32a and 32b, and a common electrode 36 is formed on the color filter layer 34.

In addition, a dielectric structure 38 is formed on the common electrode 36 on the region where the second light blocking layer 32b is formed.

The dielectric structure 38 is preferably made of a photosensitive material, and more preferably made of acrylic resin (photoacrylate) or BCB (BenzoCycloButene). In addition, the dielectric structure 38 may have a dielectric constant equal to or smaller than that of the liquid crystal, preferably 3 or less.

The dielectric structure 38 may be formed in a circular shape in the center of the pixel region as shown in the drawing, but is not limited thereto. The dielectric structure 38 may be formed in a rectangular shape, may be formed in a diagonal direction, or may be formed in a cross shape. It may be formed in a zigzag shape.

As the structure of the dielectric structure 38 is changed, the structure of the second light blocking layer 32b is also changed.

A liquid crystal layer (not shown) is formed between the first substrate 10 and the second substrate 30.

As the liquid crystal, a liquid crystal having a negative dielectric anisotropy is used. It is preferable that a chiral dopant is included in the vertical alignment liquid crystal so that the molecular alignment and the optical axis of the liquid crystal are continuously formed by applying an electric field. .

Although not shown, an alignment layer may be formed on the entire surface of at least one of the first substrate 10 and the second substrate 30.

The alignment layer may be formed by rubbing orientation treatment using a material such as a polyamide or polyimide compound, polyvinylalcohol (PVA), polyamic acid, or the like, or may be formed without orientation treatment. have.

In addition, the photoreaction may be formed using a photoreactive material such as PVCN (polyvinylcinnamate), PSCN (polysiloxanecinnamate), or CelCN (cellulosecinnamate) -based compound, or may be formed without orientation treatment. The light alignment treatment simultaneously determines the pretilt angle and the alignment direction by at least one light irradiation, wherein light irradiation preferably uses light in the ultraviolet region. Any of polarized light, linearly polarized light, and partially polarized light may be used.

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 30. The retardation film compensates for the viewing angle in the direction perpendicular to the substrate and the direction of the viewing angle change, thereby widening the region without gray inversion, and increasing the contrast ratio in the oblique direction. Although it may be formed as a negative uniaxial film or a negative biaxial film having two optical axes, a negative biaxial film is more preferable in terms of wide viewing angle.

In addition, polarizers (not shown) are attached to both substrates 10 and 30, and the polarizers may be integrally formed with the retardation film.

3A 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, and FIGS. 3B and 3C are cross-sectional views of various shapes taken along line AA ′ of FIG. 3A.

In the multi-domain liquid crystal display according to the second exemplary embodiment of the present invention shown in FIGS. 3A to 3C, an auxiliary electrode is further formed to surround the pixel electrode in order to more stably distort the electric field around the pixel electrode. The same as the first embodiment of the present invention described above. Therefore, the same reference numerals are given, and descriptions of the same parts will be omitted.

As shown in FIG. 3A, in the multi-domain liquid crystal display device according to the second embodiment of the present invention, an auxiliary electrode 40 is formed around the pixel electrode 20. Although the auxiliary electrode 40 is formed so as not to overlap with the pixel electrode 20 in the drawing, it may be formed to overlap.

The auxiliary electrode 40 is electrically connected to the common electrode 36, and when the auxiliary electrode is formed to overlap the pixel electrode 20, a storage capacitor may be formed therein.

In addition, as shown in FIG. 3B, the auxiliary electrode 40 may be formed on the same layer as the gate line under the gate insulating layer 14, and as shown in FIG. 3C, the data line 18 above the gate insulating layer 14. It may be formed on the same layer as). When the auxiliary electrode 40 is formed on the same layer as the data line 18, the pixel region is increased when the auxiliary electrode 40 is formed on the same layer as the data line 18, which is more preferable in view of the aperture ratio.

4A is a plan view of a unit pixel of a multi-domain liquid crystal display according to a third exemplary embodiment of the present invention, and FIG. 4B is a cross-sectional view taken along the line BB ′ of FIG. 4A.

The multi-domain liquid crystal display device according to the third embodiment of the present invention shown in FIGS. 4A and 4B is the same as the second embodiment of the present invention except that an electric field induction window is formed inside the pixel electrode. Therefore, the same reference numerals are given, and descriptions of the same parts will be omitted.

As shown in FIGS. 4A and 4B, in the multi-domain liquid crystal display device according to the third embodiment of the present invention, an electric field induction window 25 is formed inside the pixel electrode 20, and the electric field induction window 25 is formed. The domain is divided by.

Here, although the field induction window 25 is formed in the left and right directions, it may be formed in the vertical direction, or a plurality of field induction windows may be formed in one pixel.

Meanwhile, when divided into a plurality of domains by the electric field induction window 25, a plurality of dielectric structures 38 are formed, and a plurality of second light blocking layers 32b are formed on the dielectric structures 38. do.

In addition, when the electric field induction window 25 is formed inside the pixel electrode 20, light leakage may occur in the region. Accordingly, although not illustrated, a second light blocking layer 32b may be further formed on the second substrate so as to correspond to the region of the field induction window 25, and the auxiliary electrode 40 formed on the first substrate may be formed on the second substrate. It may be further formed up to the field induction window forming region.

5A and 5B are plan views of a liquid crystal display according to an exemplary embodiment in which a plurality of field induction windows are formed in one pixel as described above, and a cross-shaped first field induction window 25a is formed at the center of the pixel electrode 20. Referring to FIGS. ) Is formed, and the second field induction window 25b having a straight line is formed at the edge of the pixel electrode 20 so as to face the distal end of the first field induction window 25a, so that one pixel is divided into six domains. Structure.

The number of domains is changeable by the dielectric structure 38 and the field induction window.

In addition, the auxiliary electrode 40 may be formed to surround the pixel electrode 20 as shown in FIG. 5A, or the auxiliary electrode may not be formed as shown in FIG. 5B.

In addition, a rectangular dielectric structure 38 is formed at the center of each divided domain, and a second light blocking layer (not shown) is formed on the dielectric structure 38. Other components are as described above.

5A and 5B show only two first field induction windows 25a, but the present invention is not limited thereto.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and may be modified within the scope obvious to those skilled in the art.

In the multi-domain liquid crystal display device according to the present invention having the above configuration, by forming a second light shielding layer on the dielectric structure, light leakage from the dielectric structure formation region is blocked, thereby improving the contrast ratio characteristic.

In addition, in the multi-domain liquid crystal display device according to the present invention, an auxiliary electrode is formed to surround the pixel electrode, thereby stably distorting the electric field around the pixel electrode, thereby achieving stable texture.

In addition, the multi-domain liquid crystal display device according to the present invention forms an electric field induction window inside the pixel electrode to have a wide viewing angle by dividing a plurality of domains.

In addition, by using a VA (Vertical Alignment) liquid crystal containing a chiral dopant, it is possible to implement a stable mode such that the molecular arrangement and optical axis of the liquid crystal are continuously formed by applying an electric field.

Claims (14)

A first substrate and a second substrate; A plurality of gate wirings and data wirings formed vertically and horizontally on the first substrate to define pixel regions; A thin film transistor formed at an intersection point of the gate line and the data line; A pixel electrode connected to the thin film transistor and formed in the pixel area; A light blocking layer formed on the second substrate and including a first light blocking layer formed in a region corresponding to the gate wiring, a data wiring, and a thin film transistor, and a second light blocking layer formed in the pixel region; A color filter layer formed on the light blocking layer; A common electrode formed on the color filter layer; A dielectric structure formed on the common electrode and formed in an area above the second light blocking layer; And A multi-domain liquid crystal display device comprising a liquid crystal layer formed between the first substrate and the second substrate. The method of claim 1, And an auxiliary electrode surrounding the pixel electrode is further formed on the first substrate. The method of claim 2, And the auxiliary electrode is formed on the same layer as the gate line. The method of claim 2, And the auxiliary electrode is formed on the same layer as the data line. The method according to claim 1 or 2, The multi-domain liquid crystal display device, characterized in that the field induction window is formed on the pixel electrode. The method of claim 5, And the second light shielding layer is further formed in the field induction window forming region. The method of claim 5, And the auxiliary electrode is formed in the field induction window forming region. The method of claim 1, The first light blocking layer and the second light blocking layer are formed of the same material, multi-domain liquid crystal display device. The method of claim 1, The liquid crystal is a multi-domain liquid crystal display device characterized in that the chiral dopant is included in the vertical alignment liquid crystal (VA). The method of claim 1, An alignment film is formed on at least one of the first substrate and the second substrate. The method of claim 10, The alignment film is a multi-domain liquid crystal display device, characterized in that the alignment treatment. The method of claim 10, And the alignment layer is not aligned. A first substrate and a second substrate; A plurality of gate wirings and data wirings formed vertically and horizontally on the first substrate to define pixel regions; A thin film transistor formed at an intersection point of the gate line and the data line; A pixel electrode formed in the pixel region and having a cross-shaped first field induction window formed at a central portion and a side of the first field induction window formed to face an end of the first field induction window; A light blocking layer formed on the second substrate and including a first light blocking layer formed in a region corresponding to the gate wiring, a data wiring, and a thin film transistor, and a second light blocking layer formed in the pixel region; A color filter layer formed on the light blocking layer; A common electrode formed on the color filter layer; A dielectric structure formed on the common electrode and formed in an area above the second light blocking layer; An alignment layer formed on the first substrate and the second substrate; And A multi-domain liquid crystal display device comprising a liquid crystal layer formed between the first substrate and the second substrate. The method according to claim 1 or 13, And a retardation film formed on at least one of the first substrate and the second substrate.