JP2001201749A - Multidomain liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multidomain liquid crystal display device in which the texture in an image display can be stabilized and improvement in the transmittance and the multidomain effect can be realized. SOLUTION: The multidomain liquid crystal display device consists of a first substrate 31 and a second substrate 33 on which pixel regions are formed, a liquid crystal layer formed between the substrates 31 and 33, a first dielectric structure 53 formed on one of the pixel region, a second dielectric structure 53 formed on the other pixel region, and a third dielectric structure 53 formed between these dielectric structures 53.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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, in which a dielectric structure is formed around and inside a divided pixel region, and another dielectric is formed at the center of each of the divided pixel regions. The present invention relates to a multi-domain liquid crystal display device having a body structure.

[0002]

2. Description of the Related Art Recently, there has been proposed a liquid crystal display device in which a liquid crystal is driven by an auxiliary electrode which is electrically insulated from a pixel electrode without aligning the liquid crystal. FIG. 1 is a sectional view showing a unit pixel of a conventional liquid crystal display device.

A conventional liquid crystal display device comprises a first substrate and a second substrate.
And a substrate. A plurality of data lines and gate lines formed vertically and horizontally on the first substrate to divide the first substrate into a plurality of pixel regions; and a gate electrode and a gate insulating layer formed in each of the pixel regions on the first substrate. Thin film transistor (Thin) composed of a film, a semiconductor layer, an ohmic contact layer, and a source / drain electrode.
Film Transistor (TFT), a protection film 37 formed over the entire first substrate, and a pixel electrode 1 formed on the protection film 37 so as to be connected to the drain electrode.
3 and an auxiliary electrode 21 formed on the gate insulating film so as to overlap a part of the pixel electrode 13.

On the second substrate, a light shielding layer 25 formed to block light leaking from the gate wiring, the data wiring and the thin film transistor, and a color filter layer 23 formed on the light shielding layer 25 are formed. And a common electrode 17 formed on the color filter layer 23. A liquid crystal layer is formed between the first substrate and the second substrate.

The auxiliary electrode 21 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 and variously drive liquid crystal molecules in a unit pixel. This means that when a voltage is applied to the liquid crystal display element, the dielectric energy due to the distorted electric field positions the liquid crystal molecules in a desired direction. However, in order to obtain a multi-domain effect, the liquid crystal display element needs to have an open region 27 in the common electrode 17, and thus, a patterning step of the common electrode 17 is added during a manufacturing process of the liquid crystal display element. .

Furthermore, when the open region does not exist or its width is small, the degree of distortion of the electric field required for dividing the domain is weak, so that the time required for the liquid crystal molecules (directors) to reach a stable state is reduced. There is a problem that it is relatively long. Then, in order to divide the domain by the open area 27, a texture (textur
e) becomes unstable and causes a problem of deterioration in image quality. In addition, when a strong electric field is applied between the pixel electrode 13 and the auxiliary electrode 21, there has been a problem that the luminance increases and the response speed increases.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art. A dielectric structure is formed around and inside a divided pixel region, and the divided structure is formed. By forming another dielectric structure to maintain the cell gap in the shape of an island at the center of each pixel area, stabilization of texture, improvement of transmittance and multi-domain effect of image display are realized. It is an object of the present invention to provide a multi-domain liquid crystal display device that can be used.

[0008]

In order to achieve the above object, a multi-domain liquid crystal display device according to one embodiment of the present invention comprises a first substrate and a second substrate on which a pixel region is formed, and the first substrate. A liquid crystal layer formed between the first and second substrates, a first dielectric structure formed on one of the pixel regions, a second dielectric structure formed on the other of the pixel regions, It is characterized by comprising a third dielectric structure formed between the first dielectric structure and the second dielectric structure.

According to another aspect of the present invention, there is provided a multi-domain liquid crystal display device comprising: a first substrate and a second substrate each having a plurality of divided pixel regions; and a first substrate and a second substrate. A first dielectric structure formed in one of the divided pixel regions, a second dielectric structure formed in the other of the divided pixel regions, It is characterized by comprising a third dielectric structure formed between the first dielectric structure and the second dielectric structure.

In the multi-domain liquid crystal display device, the third dielectric structure may maintain a cell gap of the liquid crystal display device.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a multi-domain liquid crystal display device according to an embodiment of the present invention will be described in detail with reference to the drawings.

FIGS. 2A to 2D are plan views of a multi-domain liquid crystal display device according to a first embodiment of the present invention, and FIGS. FIG. 4 is a plan view of a multi-domain liquid crystal display device according to a second embodiment, and FIG.
(A) to (c) and (a) to (c) of FIG.
FIG. 2A is a cross-sectional view of the multi-domain liquid crystal display device of the present invention taken along line II ′.

As shown in these drawings, the multi-domain liquid crystal display device according to the present embodiment includes a first substrate 31 and a second substrate 33. A plurality of data lines and gate lines 1 formed vertically and horizontally on the first substrate 31 to divide the first substrate into a plurality of pixel regions, and a gate electrode formed on each of the pixel regions on the first substrate. A thin film transistor including a gate insulating film 35, a semiconductor layer, an ohmic contact layer, and a source / drain electrode; a protective film 37 formed over the entire first substrate; and a connection to the drain electrode on the protective film 37 Pixel electrode 13 is provided.

On the second substrate 33, a light-shielding layer 25 for blocking light leaking from the gate wiring 1, the data wiring and the thin film transistor, a color filter layer 23 formed on the light-shielding layer 25, A common electrode 17 formed on a filter layer 23;
A liquid crystal layer is formed between and the second substrate 33.

An overall structure 53 is formed on the first substrate 31 or the second substrate 33 so as to surround a pixel region.
The pixel region is divided into a plurality of domains by being formed inside the pixel region. Further, by separately forming an island-shaped dielectric structure at the center of the pixel region or at the center of each of the domains, a reference point (center point) that stabilizes the configuration of the screen and can display a uniform image. : Single point). The dielectric structure 53 formed around the pixel region can prevent a decrease in transmittance due to an existing auxiliary electrode, and can simplify the process. In other words, the dielectric structure 53 can stabilize the display of the liquid crystal display device by variously distorting the electric field applied to the liquid crystal layer, not only provide a multi-domain effect, but also maintain a cell gap. When formed to be high, it plays a role of a spacer of the liquid crystal display element (FIGS. 4 (b), (c), FIGS. 5 (b), (c)).

In order to manufacture a multi-domain liquid crystal display device having the above structure, first, a gate electrode, a gate insulating film 35, a semiconductor layer,
A thin film transistor including an ohmic contact layer and source / drain electrodes is formed. At this time, the first substrate 31
Are divided into a plurality of pixel regions, and a plurality of gate lines 1 and data lines are formed.

The gate electrode and the gate wiring 1 are composed of A
It is formed by depositing a metal such as l, Mo, Cr, Ta, or Al alloy by a sputtering method and then patterning the deposited metal. A gate insulating film 35 is formed on the
iNx or SiOx is PECVD (Plasma Enhanceme
nt Chemical Vapor Deposition)
It is formed by patterning. Subsequently, the semiconductor layer and the ohmic contact layer are a-Si and n, respectively.
After depositing ⁺ a-Si by the PECVD method, it is formed by patterning.

As another method, a gate insulating film 35 is formed by successively depositing SiNx or SiOx, a-Si and n ⁺ a-Si, and forming a-Si and n ⁺ a-S
The semiconductor layer and the ohmic contact layer may be formed by patterning i. The gate insulating film 35 may be formed of BCB (Benzo Cyclo Butene), an acrylic resin, a polyimide compound, or the like to improve an aperture ratio.

And, Al, Mo, Cr, Ta or A
After depositing a metal such as a 1 alloy by a sputtering method, patterning is performed to form data wiring and source / drain electrodes. At this time, storage electrodes are simultaneously formed so as to overlap with the gate wiring 1. The storage electrode functions as a storage capacitor together with the gate line 1.

Next, BC is applied over the entire first substrate 31.
B, an acrylic resin, a polyimide compound, or a material such as SiNx or SiOx to form a protective film 37;
After depositing a metal such as (indium tin oxide) by a sputtering method, the pixel electrode 13 is formed by patterning. At this time, the pixel electrode 13
Is connected to the drain electrode and the storage electrode through a contact hole.

On the second substrate 33, a light-shielding layer 25 is formed, and a color filter layer 23 is formed so that R (red), G (green), and B (blue) elements are repeated for each pixel. The common electrode 17 is formed thereon as a transparent electrode such as ITO like the pixel electrode 13, and a photosensitive substance is deposited on the common electrode 17 and then patterned by photolithography to form a dielectric structure. 53 is formed.

Next, the first substrate 31 and the second substrate 33
A liquid crystal is injected between the two to complete a multi-domain liquid crystal display device. Liquid crystal constituting the liquid crystal layer,
It is also possible to use a liquid crystal having positive or negative dielectric anisotropy and to include a chiral dopant.

The dielectric structure 53 is formed around and inside the pixel region to divide the pixel region into a plurality of domains and to form an island-shaped dielectric structure at the center of each domain. Further formed. Also, when formed so as to extend from the first substrate 31 or the second substrate 33 to the corresponding substrate, it serves as a spacer for maintaining a cell gap of the liquid crystal display element. The dielectric structure 53 can be formed at the same time by performing a single exposure using a transmission / semi-transmission mask or a diffraction mask.

The constituent material preferably has a dielectric constant (3 or less) equal to or smaller than the dielectric constant of the liquid crystal layer. Examples of such a material include acryl or BCB, or a black resin. It can also be formed. When formed by the black resin, since it is formed by a resin BM (resin black matrix), another light shielding layer 25 is not required, and the domain boundary formed to prevent light leakage for each domain is formed. No light-shielding layer is required in some parts.

Further, the first substrate 31 or the second substrate 3
The retardation film 29 is formed of a polymer on at least one of the substrates 3. The retardation film 29,
A negative uniaxial film having one optical axis and serving to compensate for a phase difference in a direction depending on a viewing angle of a substrate. Therefore, the area without gradation inversion is expanded, the contrast ratio is increased from the tilt direction,
By forming one pixel in multi-domain, it is possible to effectively compensate the viewing angle in the left-right direction.

In the multi-domain liquid crystal display device of the present invention, a negative biaxial film may be formed as a retardation film in addition to the negative uniaxial film, and the biaxial liquid crystal display device may be formed of a biaxial material. The obtained negative biaxial film can obtain a wider viewing angle characteristic than the uniaxial film. After attaching the retardation film, polarizers (not shown) are attached to both substrates. At this time, the polarizer can be formed integrally with the retardation film and attached.

The multi-domain liquid crystal display device shown in FIGS. 2A to 2D has a dielectric structure 53 around a pixel region.
Is formed inside the pixel region, and the pixel region is vertically divided into two domains, three domains, and four domains. An island-shaped dielectric structure is independently formed at the center of the pixel region and each domain, and functions as a reference point for screen display.

The multi-domain liquid crystal display device shown in FIGS. 3A to 3D has a dielectric structure 53 around a pixel region.
Is formed inside the pixel region, and the pixel region is vertically divided into two domains, four domains, six domains, and eight domains. An island-shaped dielectric structure is independently formed at the center of the pixel region and each domain, and functions as a reference point for screen display.

FIG. 4A shows a structure in which all of the dielectric structure 53 is formed in a low protrusion shape on the second substrate 33. FIG. 4B shows a structure in which the dielectric structure 53 is formed. 53 is formed on the second substrate 33, and the island-shaped dielectric structure 53 extends from the second substrate 33 toward the first substrate 31 so as to maintain the cell gap of the liquid crystal display element. FIG. 4C shows that the dielectric structure 53 is
The dielectric structure 53 is formed on the second substrate 33, and has an island-like structure extending from the first substrate 31 toward the second substrate 33.

FIG. 5A shows that the dielectric structure 53 is
FIG. 5B shows a structure in which the dielectric structure 53 is formed on the first substrate 31, and the islands of the dielectric structure 53 are formed on the first substrate 31. FIG. 4C shows a structure in which the dielectric structure 53 extends from the second substrate 33 toward the first substrate 31 so as to maintain the cell gap of the liquid crystal display element. The dielectric structure 53 is formed on the substrate 31 and has an island shape extending from the first substrate 31 toward the second substrate 33.

FIGS. 6 (a) and 6 (b) are diagrams showing textures at intermediate gray levels when the multi-domain liquid crystal display device of the present invention and the conventional liquid crystal display device are driven.
FIG. 6A is a view showing a texture appearing on a screen when the multi-domain liquid crystal display device of the present invention is driven. In FIG. It can be confirmed that a uniform texture is formed for each domain. FIG. 6B is a drawing showing a texture appearing on the screen when the conventional liquid crystal display element is driven, and a defective image display due to the formation of a non-uniform texture different for each domain is seen.

Further, in the multi-domain liquid crystal display device of the present invention, an alignment film (not shown) is formed over the whole of the first substrate 31 and / or the second substrate 33. The alignment film is formed of a photoreactive substance, that is, PVCN (polyvinylcin).
The photo-alignment film can be formed by using a material such as namate), PSCN (polysiloxanecinnamate), or CelCN (cellulosecinnamate). In addition,
As the material for the alignment film, any material can be used as long as it is a substance suitable for other optical alignment treatment. In the photo-alignment film, light is irradiated at least once to simultaneously determine a pretilt angle formed by liquid crystal molecules and an alignment direction or a pretilt direction, thereby ensuring alignment stability of the liquid crystal. Is done. As light for such optical alignment, light in the ultraviolet region is suitable, and any of 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 substrate 31 and the second substrate 33, or may be applied to both substrates.
It is also possible to perform different alignment treatments on both substrates, or to form only an alignment film and not to perform the alignment treatment.

It is also possible to form a multi-domain liquid crystal display element divided into at least two regions by performing an alignment treatment, so that the liquid crystal molecules of the liquid crystal layer are aligned in a different manner on each region. it can. That is, each pixel is divided into four regions such as a + shape or a X shape, or divided into horizontal, vertical, or both diagonal lines, and each region and each substrate are formed with different alignment processes or different alignment directions. By doing so, a multi-domain effect can be realized. At least one of the divided regions can be a non-oriented region, and all regions can be non-oriented regions.

[0035]

According to the multi-domain liquid crystal display device of the present invention, a dielectric structure is formed around and inside the divided pixel region, and an island or cell gap is maintained at the center of each of the divided pixel regions. Inducing electric field distortion by forming another dielectric structure to facilitate the adjustment of the orientation direction in the domain and stabilizing the texture in the image display, wide viewing angle and The multi-domain effect can be maximized. Also,
There is an advantage that the transmittance can be improved because the auxiliary electrode of the conventional liquid crystal display element is not formed.

[Brief description of the drawings]

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

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

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

FIG. 4 is a cross-sectional view of the multi-domain liquid crystal display device of the present invention taken along line II ′ of FIG. 2 (a).

FIG. 5 is a cross-sectional view taken along line II ′ of FIG. 2A according to another embodiment.
FIG. 2 is a cross-sectional view of the multi-domain liquid crystal display device of the present invention, taken along a line.

FIGS. 6A and 6B are diagrams illustrating textures when driving the multi-domain liquid crystal display device of the present invention and a conventional liquid crystal display device, respectively.

[Explanation of symbols]

 1: gate wiring 13: pixel electrode 17: common electrode 23: color filter layer 25: light shielding layer 27: open area 29: retardation film 31: first substrate 33: second substrate 35: gate insulating film 37: protective film 53 ： Dielectric structure

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Li Jun-fu South Korea Republic of Korea , 107-1702

Claims (13)

[Claims] A first substrate on which a pixel region is formed;
A substrate; a liquid crystal layer formed between the first substrate and the second substrate; a first dielectric structure formed on one of the pixel regions; and a second dielectric structure formed on the other of the pixel regions. A multi-domain liquid crystal display device comprising: a dielectric structure; and a third dielectric structure formed between the first dielectric structure and the second dielectric structure. 2. The multi-domain liquid crystal display device according to claim 1, wherein the third dielectric structure maintains a cell gap of the liquid crystal display device. 3. The multi-domain liquid crystal display device according to claim 2, wherein the third dielectric structure extends from the first substrate to the second substrate. 4. The multi-domain liquid crystal display device according to claim 2, wherein the third dielectric structure extends from the second substrate to the first substrate. 5. The multi-domain liquid crystal display device according to claim 1, wherein the height of the third dielectric structure is the same as the height of the first dielectric structure. 6. The multi-domain liquid crystal display device according to claim 1, wherein the height of the third dielectric structure is the same as the height of the second dielectric structure. 7. The width of the third dielectric structure is equal to the first dielectric structure.
2. The multi-domain liquid crystal display device according to claim 1, wherein the width is larger than the width of the second dielectric structure. 8. The multi-domain liquid crystal display device according to claim 1, wherein the dielectric structure is formed so as to surround at least three sides of the pixel region. 9. A first substrate and a second substrate on which a pixel region divided into a plurality of regions is formed; a liquid crystal layer formed between the first substrate and the second substrate; A first dielectric structure formed in one of the pixel regions; a second dielectric structure formed in the other of the divided pixel regions; a first dielectric structure and a second dielectric A multi-domain liquid crystal display device comprising a third dielectric structure formed between the structure and the third dielectric structure. 10. The multi-domain liquid crystal display device according to claim 9, wherein the third dielectric structure maintains a cell gap of the liquid crystal display device. 11. The multi-domain liquid crystal display device according to claim 9, wherein the third dielectric structure is located at the center of each of the divided pixel regions. 12. The multi-domain liquid crystal display device according to claim 9, wherein the dielectric structure is formed so as to surround each of the divided pixel regions. 13. The multi-domain liquid crystal display device according to claim 9, wherein each of the divided pixel regions has different driving characteristics.