KR100313950B1 - Multi-domain liquid crystal display device - Google Patents

Abstract

The multi-domain liquid crystal display device according to the present invention includes a first and second substrates facing each other, a liquid crystal layer formed between the first substrate and the second substrate, and a pixel formed vertically and horizontally on the first substrate. A plurality of gate wirings and data wirings defining an area, a pixel electrode formed in the pixel region, a color filter layer having an electric field distortion hole on its surface on the second substrate, and an entire second substrate on the color filter layer. And an organic or inorganic protective film formed over, a common electrode formed on the organic or inorganic protective film, and an alignment film formed on at least one of the first and second substrates.

Description

Multi-domain liquid crystal display device

The present invention relates to a liquid crystal display device, and more particularly, to a multi-domain liquid crystal display device in which an organic protective film or an inorganic protective film is formed on a color filter layer.

Recently, a liquid crystal display device for driving a liquid crystal by an auxiliary electrode electrically insulated from the pixel electrode without aligning the liquid crystal has been proposed. 1A and 1B are cross-sectional views of unit pixels of the above-described conventional liquid crystal display device.

Conventional liquid crystal display devices include a first substrate and a second substrate, a plurality of data wirings and gate wirings formed vertically and horizontally on the first substrate to divide the first substrate into a plurality of pixel regions, and pixels on the first substrate. Thin Film Transistors (TFTs) formed in each of the regions and comprising a gate electrode, a gate insulating film, a semiconductor layer, an ohmic contact layer, and a source / drain electrode, and a protective film formed over the entire first substrate. And a pixel electrode 13 (FIG. 1A) formed to be connected to the drain electrode on the passivation layer, and an auxiliary electrode 15 formed in a region other than the pixel electrode 13 on the passivation layer. )

The light blocking layer 25 for blocking light leaking from the gate wiring, the data wiring, and the thin film transistor on the second substrate, the color filter layer 23 formed on the light blocking layer 25, and A common electrode 17 formed on one color filter layer 23 and a liquid crystal layer formed between the first substrate and the second substrate. In addition, an overcoat layer 31 may be formed on the color filter layer 23, and the overcoat layer 31 is mainly formed of an organic film (FIGS. 1B and 1D).

The auxiliary electrode 15 formed around the pixel electrode 13 and the open area 27 of the common electrode 17 distort the electric field applied to the liquid crystal layer, thereby driving various liquid crystal molecules in the unit pixel. This means that when a voltage is applied to the liquid crystal display, the dielectric energy due to the distorted electric field places the liquid crystal director in a desired direction.

However, the liquid crystal display device requires an open area 27 in the common electrode 17 in order to obtain a multi-domain effect. To this end, a process of patterning the common electrode 17 in the manufacturing process of the liquid crystal display device is added. do. On the other hand, if the open area is not present or the width thereof is small, the time to reach a stable state of the liquid crystal director becomes relatively long.

Further, in the process of depositing and patterning the common electrode, since the common electrode 17 is formed directly on the color filter layer 23 or the common electrode is formed directly on the organic protective layer 31, the adhesion of the common electrode is lowered. As a result, there is a problem that the size and uniformity of the open area is inferior. Although an overcoat layer is sometimes formed on the color filter layer, in this case, the purpose is to planarize the surface in order to protect the color filter layer and to form the electrode uniformly. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the prior art, by forming an organic protective film or an inorganic protective film on a color filter layer to increase the adhesion and pattern precision of an electrode, and patterning a color filter layer or a common electrode, thereby multiplying an electric field. It is an object to provide a domain liquid crystal display device.

In order to achieve the above object, the multi-domain liquid crystal display device according to the present invention, the opposing first substrate and second substrate, the liquid crystal layer formed between the first substrate and the second substrate, and the first A plurality of gate wirings and data wirings formed vertically and horizontally on a substrate to define a pixel region, a pixel electrode formed in the pixel region, a color filter layer having an electric field distortion hole on the surface of the second substrate, and An organic or inorganic protective film formed over the second substrate on one color filter layer, a common electrode formed on the organic or inorganic protective film, and an alignment film formed on at least one of the first and second substrates described above. Is done.

A multi-domain liquid crystal display device according to another exemplary embodiment of the present invention includes a first and second substrates facing each other, a liquid crystal layer formed between the first and second substrates, and a vertical and horizontal width on the first substrate. A plurality of gate wirings and data wirings formed in the pixel region, a pixel electrode formed in the pixel region, a color filter layer formed on the second substrate, and an entire second substrate on the color filter layer. An organic protective film formed, an inorganic protective film formed over the entire second substrate on the organic protective film, a common electrode having an electric field guide window therein on the inorganic protective film, and among the first and second substrates. It is made of an alignment film formed on at least one substrate.

The color filter layer or the common electrode is formed by patterning.

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

2 is a cross-sectional view of a multi-domain liquid crystal display device according to a first embodiment of the present invention.

3 is a cross-sectional view of a multi-domain liquid crystal display device according to a second embodiment of the present invention.

4A to 4D are plan views of a multi-domain liquid crystal display device according to an exemplary embodiment of the present invention.

5A through 5C are plan views of a multi-domain liquid crystal display device according to an exemplary embodiment of the present invention.

6A through 6D are plan views of a multi-domain liquid crystal display device according to an exemplary embodiment of the present invention.

7A to 7D are plan views of a multi-domain liquid crystal display device according to an exemplary embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

1: Gate wiring

3: Data wiring

5: semiconductor layer

7: source electrode

9: drain electrode

10: mask

11: gate electrode

13: pixel electrode

14 photosensitive film

15: auxiliary electrode

17: common electrode

19: Field distortion hole

23: color filter layer

25: light shielding layer

27: open area

31: organic protective film

33: Weapon Shield

39: electric field induction window

Hereinafter, a multi-domain liquid crystal display device according to the present invention will be described in detail with reference to the drawings.

2 is a cross-sectional view of a multi-domain liquid crystal display device according to a first embodiment of the present invention.

As shown in the above drawings, the multi-domain liquid crystal display device of the present invention comprises a plurality of data which are formed vertically and horizontally on the first substrate and the second substrate and the first substrate to divide the first substrate into a plurality of pixel regions. A gate electrode 11, a gate insulating film, a semiconductor layer 5, an ohmic contact layer and a source / drain electrode 7, 9 formed in each of the wiring 3 and the gate wiring 1 and the pixel region on the first substrate. The thin film transistor includes a thin film transistor, a passivation film (not shown) formed over the entire first substrate, and a pixel electrode 13 formed to be connected to the drain electrode 9 on the passivation film.

Then, the color filter layer 23 formed on the second substrate, the organic protective film 31 formed on the color filter layer 23, the inorganic protective film 33 formed on the organic protective film 31, The common electrode 17 formed on the inorganic protective film 33 and a liquid crystal layer formed between the first substrate and the second substrate.

As shown in FIGS. 2A and 2B, the common electrode 17 is formed by patterning the field induction window 39, thereby inducing an electric field distortion effect.

FIG. 3 is a view showing a second embodiment of the present invention. The field distortion effect may be realized by patterning the field distortion holes 19 in the color filter layer 23. At this time, the organic or inorganic protective film 31, 33 formed on the color filter layer 23, the common electrode 17 formed on the organic or inorganic protective film 31, 33, and The liquid crystal layer is formed between the first substrate and the second substrate.

As a modification of the present invention, the embodiment shown in Figs. 2B and 3B further comprises an auxiliary electrode 15 formed in a region other than the pixel electrode 13 above the protective film on the first substrate.

In order to manufacture the multi-domain liquid crystal display device having the above-described structure, first, the gate electrode 11, the gate insulating film, the semiconductor layer 5, the ohmic contact layer and the source / drain electrode 7 are respectively formed in each pixel area of the first substrate. A thin film transistor consisting of 9) is formed. At this time, a plurality of gate wirings 1 and data wirings 3 are formed which divide the first substrate into a plurality of pixel regions. The gate electrode 11 and the gate / data wirings 1 and 3 are formed by sputtering a metal such as Al, Mo, Cr, Ta, or an Al alloy, and then patterned thereon. The gate insulating film is formed by stacking SiN _X or SiO _X by plasma CVD and then patterning. Subsequently, the semiconductor layer 5 and the ohmic contact layer are formed by laminating and patterning a-Si and n ⁺ a-Si, respectively, by plasma CVD (Plasma Chemical Vapor Deposition).

Subsequently, a protective film (not shown) is formed of a material such as BCB (BenzoCycloButene), an acrylic resin, a polyimide compound, SiN _X or SiO _X , and the ITO (indium) is formed over the first substrate. A metal electrode 13 is formed by stacking a metal such as tin oxide), Al, or Cr by a sputtering method and then patterning the metal. In this case, the pixel electrode 13 is formed by patterning once with the same metal or twice with different kinds of metals.

In the case of forming the auxiliary electrode 15, a metal such as Al, Mo, Cr, Ta, or Al alloy is stacked and formed by sputtering and then patterning.

On the second substrate, a color filter layer 23 having an electric field distortion hole 19 is formed so that R, G, and B (red, green, blue) elements are repeated for each pixel, and acrylic or poly is formed on the entire second substrate. After forming an organic protective film 31 made of a material such as a medi-based material or an inorganic protective film 33 made of a material such as SiN _x or SiO _x , a metal such as indium tin oxide (ITO), Al or Cr, etc. may be sputtered After lamination, the common electrode 17 is formed by patterning, and liquid crystal is injected between the first substrate and the second substrate to complete the liquid crystal display device. In the case where the electric field induction window 39 is formed inside the common electrode 17, the organic protective layer 31 and the inorganic protective layer 33 are formed on the color filter layer 23.

In addition, in the case where the electric field induction window 39 is formed inside the common electrode 17, as shown in FIGS. 4A to 4D and 5A to 5C, patterning is performed in two domains by lengthwise horizontally, vertically, and diagonally. The divided effect is obtained, or the X-shape, the + -shape, and the X- and + -shape are simultaneously patterned to realize the effect of dividing into 4 domains and multi-domain.

In the case where the field distortion holes 19 are formed on the surface of the color filter layer 23, the color distortion layer 19 is formed at the same time as the color filter layer 23 is formed using a mask having various shapes of slits. Pattern. The above-described electric field distortion hole 19 can also be divided into two domains by patterning the pattern horizontally, vertically, and diagonally, or by simultaneously patterning the X-shape, the + -shape, and the X-shape and the + -shape at the same time. Implement the effect of splitting into domains and multidomains.

At this time, since the common electrode 17 is formed along the surfaces of the color filter layer 23 and the organic / inorganic protective film 31, 33, the electric field is formed by the electric field distortion hole 19 of the color filter layer 23. Distorts the resulting multi-domain effect.

That is, by forming the thickness of the color filter layer 23 in the range of about 1.0 μm to 2.0 μm, the response characteristics are improved, and the electric field distortion effect is increased by the field distortion holes 19, thereby stabilizing the liquid crystal molecules when the liquid crystal display is driven. To increase the multidomain effect.

6A to 6D and 7A to 7D show a multi-domain liquid crystal display according to various embodiments when the auxiliary electrode 15 is formed on the first substrate as in the liquid crystal display device shown in FIGS. 2B and 3B. Top view of the device.

In the liquid crystal display device shown in Figs. 6A to 6D, the auxiliary electrode 15 and the pixel electrode 13 are separated by a protective film (not shown), so that the gate wiring 1 and the data wiring 3 are auxiliary. The interference of the distorted electric field of the electrode 15 is prevented. The protective film is formed by applying materials such as SiN _X or SiO _X. In addition, when the auxiliary electrode 15 and the pixel electrode 13 are formed to overlap the thin film transistor and / or the data wiring 3, crosstalk occurs, and thus, the auxiliary electrode 15 and the pixel electrode 13 are described above. ) Is formed so as not to overlap the protective film.

As compared with the liquid crystal display device of FIG. 7A, the liquid crystal display device shown in FIGS. 6C and 6D has a liquid crystal display device in which the auxiliary electrode 15 is formed only on the data wiring 3 side and the liquid crystal formed only on the gate wiring 1 side, respectively. The display element is shown.

In the liquid crystal display device shown in Figs. 7A to 7D, the protective film is formed of BCB (Benzocyclobutene), an acrylic resin, or a polyimide compound, which is an organic insulating film, so that the auxiliary electrode on the side of the data wiring 3 has the data wiring (3). It is formed in any part of (), and an opening ratio improves. In addition, the position of the auxiliary electrode may be formed at any position. Therefore, the pixel area is enlarged as compared with the liquid crystal display of FIG. 6.

7C and 7D show that the liquid crystal display device shown in FIG. 7A has a liquid crystal display device in which an auxiliary electrode 15 is formed only on any part of the data line 3 and any part of the gate line 1. It shows only the liquid crystal display device formed.

In addition, the multi-domain liquid crystal display device of the present invention forms an alignment film (not shown) over the entirety of the first substrate and / or the second substrate. In this case, a material such as polyamide or polyimide compound, PVA (polyvinylalcohol), polyamic acid or SiO ₂ may be used as the alignment material constituting the alignment layer. In the case of determining the orientation direction by use, any material suitable for other rubbing treatments can be applied.

In addition, the alignment layer may be formed of a photoreactive material, that is, a material such as PVCN (polyvinylcinnamate), PSCN (polysiloxanecinnamate), or CelCN (cellulosecinnamate) -based compound to form a photoalignment film, and other optical alignment treatment Any material suitable for is applicable. The photoalignment layer is irradiated with light at least once to simultaneously determine the pretilt angle and alignment direction or pretilt direction of the liquid crystal molecules. As for the light used for the optical alignment, light in the ultraviolet region is suitable, and any light among non-polarized light, linearly polarized light, and partially polarized light may be used.

The rubbing method or the photo-alignment method may be applied to only one of the first substrates or the second substrates, or may be treated on both substrates, or may be subjected to different alignment treatments on both substrates, or only an alignment film is formed and the alignment treatment is performed. It is also possible not to.

In addition, by performing the above-described alignment process, a multi-domain liquid crystal display device divided into at least two regions can be formed so that the liquid crystal molecules of the liquid crystal layer can be differently aligned on each region. That is, the multi-domain effect is realized by dividing each pixel into four regions, such as + or × characters, or by dividing them into horizontal, vertical, or diagonal lines, and by forming different alignment processes or orientation directions in each region and each substrate. do. At least one of the divided regions may be a non-oriented region, and the entire region may be a non-oriented region.

In the multi-domain liquid crystal display device of the present invention, the long axis of the liquid crystal molecules constituting the liquid crystal layer is horizontally aligned (homogeneous alignment) in which the first and second substrates are aligned in parallel with the substrate surface. Vertically oriented homeotropic alignment is possible, and the tilted alignment or twisted alignment is oriented at a specific angle with respect to the substrate surface of the first substrate or the second substrate. alignment, any type of orientation and mode, such as hybrid alignment oriented horizontally with respect to the substrate face of either the first substrate or the second substrate and perpendicular to the substrate face of the other substrate. This has the advantage of being possible.

In the multi-domain liquid crystal display device of the present invention, an organic protective film and an inorganic protective film may be formed on the color filter layer to increase the adhesion of the electrode, thereby realizing a multi-domain liquid crystal display device having excellent pattern uniformity and precision.

In addition, by forming an electric field distortion hole in the color filter layer, or by forming an electric field induction window in the common electrode, and inducing an electric field distortion by the auxiliary electrode, the effect of simplifying the process and maximizing the multi-domain effect, to realize a wide viewing angle There is.

Claims (42)

Opposing first and second substrates, A liquid crystal layer formed between 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 pixel electrode formed in the pixel region, A color filter layer having a field distortion hole formed on the second substrate; An organic or inorganic protective film formed over the second substrate on the color filter layer; A common electrode formed on the organic or inorganic protective film, and A multi-domain liquid crystal display device comprising an alignment film formed on at least one of the first substrate and the second substrate. The multi-domain liquid crystal display device according to claim 1, wherein the color filter layer is formed by patterning. The multi-domain liquid crystal display device according to claim 1, wherein the material constituting the organic protective film is selected from the group consisting of acrylic based materials and polyimide based materials. The multi-domain liquid crystal display device according to claim 1, wherein the material constituting the inorganic protective film is selected from the group consisting of SiN _x and SiO _x . The multi-domain liquid crystal display of claim 1, further comprising an auxiliary electrode on the same layer as the pixel electrode. 6. The multi-domain liquid crystal display device according to claim 5, wherein the auxiliary electrode is formed in a region other than the region where the pixel electrode exists. The multi-domain liquid crystal display device of claim 5, wherein the auxiliary electrode is electrically connected to the common electrode. The multi-domain liquid crystal display of claim 1, wherein the material constituting the pixel electrode is selected from the group consisting of indium tin oxide (ITO), Al, and Cr. The multi-domain liquid crystal display device according to claim 5, wherein the material constituting the auxiliary electrode is selected from the group consisting of indium tin oxide (ITO), Al, Mo, Cr, Ta, Ti and Al alloys. . The multi-domain liquid crystal display of claim 1, wherein the material constituting the common electrode is made of indium tin oxide (ITO). The multi-domain liquid crystal display device according to claim 1, wherein the pixel region is divided into at least two regions so that the liquid crystal molecules of the liquid crystal layer exhibit different driving characteristics on each region. The multi-domain liquid crystal display device according to claim 1, wherein the alignment film is divided into at least two regions so that the liquid crystal molecules of the liquid crystal layer exhibit different alignment characteristics on each region. 13. The multi-domain liquid crystal display device according to claim 12, wherein at least one of the regions of the alignment film is subjected to an alignment process. The multi-domain liquid crystal display device according to claim 12, wherein all of the regions of the alignment film are not aligned. The multi-domain liquid crystal display device according to claim 12, wherein at least one of the regions of the alignment layer is rubbed in alignment. The method of claim 15, wherein the material constituting the alignment layer is selected from the group consisting of polyimide and polyamide-based compounds, polyvinylalcohol (PVA), polyamic acid, and SiO ₂ . A multi-domain liquid crystal display device. 13. The multi-domain liquid crystal display device according to claim 12, wherein at least one of the regions of the alignment layer is optically aligned. The multi-domain liquid crystal display device according to claim 17, wherein the material constituting the alignment layer is selected from the group consisting of polyvinylcinnamate (PVCN), polysiloxanecinnamate (PSCN), and cellulosecinnamate (CelCN) -based compounds. 18. The multi-domain liquid crystal display device according to claim 17, wherein the light used in the optical alignment is light in an ultraviolet region. 18. The multi-domain liquid crystal display device according to claim 17, wherein the optical alignment irradiates light at least once. The multi-domain liquid crystal display device according to claim 1, wherein the liquid crystal constituting the liquid crystal layer is a liquid crystal having positive or negative dielectric anisotropy. Opposing first and second substrates, A liquid crystal layer formed between 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 pixel electrode formed in the pixel region, A color filter layer formed on the second substrate; An organic protective film formed over the second substrate on the color filter layer; An inorganic protective film formed over the second substrate on the organic protective film; A common electrode having an electric field guide window therein on the inorganic protective film, and A multi-domain liquid crystal display device comprising an alignment film formed on at least one of the first substrate and the second substrate. 23. The multi-domain liquid crystal display device according to claim 22, wherein the common electrode is formed by patterning. The multi-domain liquid crystal display device according to claim 22, wherein the material constituting the organic protective film is selected from the group consisting of acrylic based materials and polyimide based materials. 23. The multi-domain liquid crystal display device according to claim 22, wherein the material constituting the inorganic protective film is selected from the group consisting of SiN _x and SiO _x . 23. The multi-domain liquid crystal display of claim 22, further comprising an auxiliary electrode on the same layer as the pixel electrode. 27. The multi-domain liquid crystal display device according to claim 26, wherein the auxiliary electrode is formed in a region other than the region where the pixel electrode exists. 27. The multi-domain liquid crystal display of claim 26, wherein the auxiliary electrode is electrically connected to the common electrode. 23. The multi-domain liquid crystal display device according to claim 22, wherein the material constituting the pixel electrode is selected from the group consisting of indium tin oxide (ITO), Al, and Cr. 27. The multi-domain liquid crystal display device of claim 26, wherein the material constituting the auxiliary electrode is selected from the group consisting of indium tin oxide (ITO), Al, Mo, Cr, Ta, Ti, and Al alloys. . 23. The multi-domain liquid crystal display of claim 22, wherein the material constituting the common electrode is made of indium tin oxide (ITO). 23. The multi-domain liquid crystal display device according to claim 22, wherein the pixel region is divided into at least two regions so that the liquid crystal molecules of the liquid crystal layer exhibit different driving characteristics on each region. 23. The multi-domain liquid crystal display device according to claim 22, wherein the alignment film is divided into at least two regions so that the liquid crystal molecules of the liquid crystal layer exhibit different alignment characteristics on each region. 34. The multi-domain liquid crystal display device according to claim 33, wherein at least one of the regions of the alignment film is subjected to an alignment process. 34. The multi-domain liquid crystal display device according to claim 33, wherein all of the regions of the alignment film are not aligned. 34. The multi-domain liquid crystal display device according to claim 33, wherein at least one of the regions of the alignment layer is rubbed. 37. The method of claim 36, wherein the material constituting the alignment layer is selected from the group consisting of polyimide and polyamide-based compounds, polyvinylalcohol, polyamic acid, and SiO ₂ . A multi-domain liquid crystal display device. 34. The multi-domain liquid crystal display device according to claim 33, wherein at least one of the regions of the alignment layer is optically aligned. 39. The multi-domain liquid crystal display device according to claim 38, wherein the material constituting the alignment layer is selected from the group consisting of polyvinylcinnamate (PVCN), polysiloxanecinnamate (PSCN), and cellulosecinnamate (CelCN) -based compounds. The multi-domain liquid crystal display device according to claim 38, wherein the light used in the optical alignment is light in an ultraviolet region. The multi-domain liquid crystal display device according to claim 38, wherein the optical alignment irradiates light at least once. 23. The multi-domain liquid crystal display device according to claim 22, wherein the liquid crystal constituting the liquid crystal layer is a liquid crystal having positive or negative dielectric anisotropy.