Liquid crystal display

Provided is a liquid crystal display, including a first substrate including a plurality of pixel regions including a transmissive light area and a non-transmissive light area, a second substrate facing the first substrate and a liquid crystal layer disposed between the first substrate and the second substrate, wherein the pixel regions includes color filters disposed on a base substrate, a pixel electrode disposed on each of the color filters at the transmissive light area and a black column spacer at a region except a region corresponding to the transmissive light area, wherein the each of the color filters has substantially rectangular shape with a long side and a short side, and wherein the long side has a recess portion in which a part of a long side corresponding to the non-transmissive light area is removed.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2014-0150311, filed on Oct. 31, 2014, in the Korean Intellectual Property Office, the entire content of which is incorporated herein by reference in its entirety.

BACKGROUND

Embodiments relate to a liquid crystal display, and more particularly, to a liquid crystal display with enhanced display qualities.

2. Description of the Related Art

Generally, a liquid crystal display may include an array substrate, a facing substrate facing the array substrate and a liquid crystal layer between the array substrate and the facing substrate. The liquid crystal display may include a color filter for implementing images in color. Recently, liquid crystal displays include color filter on array (COA) substrate, that is, a structure where the color filter is provided on the array substrate.

Also, to prevent a misalignment from occurring in a process coupling the facing substrate where the COA substrate and a light blocking member are formed to the array substrate, research is being conducted on a black matrix on array (BOA) substrate that forms the light blocking member on the COA substrate. Also, a black column spacer BCS that forms a black matrix that blocks light and a column spacer that maintains a cell gap at the same time using the same material is being developed.

The black column spacer may include a light blocking portion and a cell gap retaining portion. The light blocking portion may block light, and the cell-gap retaining portion may maintain a cell gap of the liquid crystal display.

Meanwhile, the light blocking portion may be provided at a region of the liquid crystal display where light does not penetrate, that is, a non-transmissive light area. A part of the light blocking portion may be provided on a region where adjacent color filters overlap. The light blocking portion on the region where the color filters overlap may have a height higher than the other portion. Accordingly, a height difference between the light blocking portion of the region where the color filters overlap and the cell gap retaining portion may decrease.

The decrease in height difference between the light blocking portion and the cell gap retaining portion may cause active unfilled area (AUA) defects. Also, the cell gap of a liquid crystal cell may become non-uniform. Consequently, a problem of stain on the screen may arise.

SUMMARY

Embodiments may be realized by providing a liquid crystal display, including a first substrate including a plurality of pixel regions including a transmissive light area and a non-transmissive light area, a second substrate facing the first substrate, and a liquid crystal layer disposed between the first substrate and the second substrate, wherein the pixel regions includes color filters disposed on a base substrate at the pixel regions, a pixel electrode disposed on each of the color filters at the transmissive light area, and a black column spacer disposed at a region except a region corresponding to the transmissive light area, wherein the each of the color filters has a substantially rectangular shape with a long side and a short side, and wherein the long side has a recess portion in which a part of a long side corresponding to the non-transmissive light area is removed.

Adjacent color filters may at a region between adjacent transmissive light areas but do not overlap at a region where the recess portion is formed.

The black column spacer may include a light blocking portion surrounding the transmissive light area, and a cell gap retaining portion disposed at the non-transmissive light area and maintaining a distance between the first substrate and the second substrate.

The light blocking portion disposed at a region where the adjacent color filters overlap each other may be protruded in a direction of the second substrate due to the overlapping of the color filters.

The pixel electrode may include a hexagon-shaped first pixel electrode provided on the color filter and including a rhombus-shaped open portion at a center, a protective layer covering the first pixel electrode, and a second pixel electrode disposed on the protective layer, wherein the second pixel electrode may include a first sub-pixel electrode overlapping the open portion of the first pixel electrode, and a second sub-pixel electrode surrounding the first sub-pixel electrode and spaced apart from the first sub-pixel electrode.

The first sub-pixel electrode may include a cross-shaped stem and a plurality of first branch portions extending from the stem portion, and the second sub-pixel electrode may include a peripheral portion having a substantially rectangular shape and a plurality of second branch portions extending from the peripheral portion.

According to an embodiment, a liquid crystal display may include a first substrate including a plurality of pixel regions divided into a transmissive light area and a non-transmissive light area, a second substrate facing the first substrate and a liquid crystal layer disposed between the first substrate and the second substrate, wherein the first substrate may include a gate line disposed on the first base substrate, a data line crossing the gate line by being insulated from the gate line, a plurality of thin film transistors coupling to the gate line and the data line and disposed at the non-transmissive light area, a first protective layer covering the thin film transistors, color filters disposed on the first protective layer at the pixel regions, a first pixel electrode disposed on each of the color filters and coupling to one of the thin film transistors, a second protective layer covering the first pixel electrode, a second pixel electrode provided on the second protective layer and coupling to another one of the thin film transistors and a black column spacer disposed at a region except a region corresponding to the transmissive light area, wherein the color filters are quadrilateral-shaped with a long vertical side and a chamfer-shaped part of a long side corresponding to an adjacent color filter at the non-transmissive light area.

The adjacent color filters may overlap at a region between adjacent transmissive light regions and do not overlap at a region where the recessed portion is formed.

The black column spacer may include a light blocking portion surrounding the transmissive light area, and a cell gap retaining portion disposed at the non-transmissive light area and maintaining a distance between the first substrate and the second substrate.

The light blocking portion disposed at a region where the adjacent color filters overlap may protrude in a direction of the second substrate due to the overlapping of the color filters.

A third protective layer may be further included disposed between the color filter and the first pixel electrode.

The first pixel electrode may be hexagon-shaped and may include a rhombus-shaped open portion at a center, and the second pixel electrode may include a first sub-pixel electrode overlapping the open portion of the first pixel electrode and a second sub-pixel electrode, spaced apart from the first pixel electrode and surrounding of the first sub-pixel electrode.

The first sub-pixel electrode may include a cross-shaped stem portion and a plurality of first branch portions extending from the stem portion, and the second sub-pixel electrode may include a peripheral portion having a substantially rectangular shape and a plurality of second branch portions extending from the peripheral portion.

Embodiments may be realized by providing a liquid crystal display, including a first substrate including a plurality of pixel regions including a transmissive light area and a non-transmissive light area, the pixel regions including adjacent subpixel regions, a second substrate facing the first substrate, and a liquid crystal layer disposed between the first substrate and the second substrate, wherein the pixel regions includes color filters disposed on a base substrate, a pixel electrode disposed on each of the color filters at the transmissive light area, and a black column spacer disposed at a region except a region corresponding to the transmissive light area, wherein an overlap length of adjacent color filters at a region corresponding to the transmissive light areas is longer than that in the non-transmissive light area.

Each of the color filters may have a recess portion at a region corresponding to the non-transmissive light area.

The adjacent color filters at a region corresponding to the non-transmissive light area may not overlap.

The recess portion may have a trapezoidal shape in which a long base is closer to the pixel edge than a short base. The long base and the short base may be substantially parallel to the pixel edge.

DETAILED DESCRIPTION

In the following detailed description, only certain exemplary embodiments of the present inventive concept have been shown and described, simply by way of illustration. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present inventive concept. Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. In addition, it will be understood that when an element or layer is referred to as being “on”, “connected to” or “coupled to” another element or layer, it can be directly on, connected or coupled to the other element or layer or intervening elements or layers may be present between the element or layer and the another element or layer. In contrast, when an element is referred to as being “directly on,” “directly connected to” or “directly coupled to” another element or layer, there are no intervening elements or layers present between the element or layer and the another element or layer. Like numbers refer to like elements throughout the specification. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

FIG. 1is an exploded perspective view illustrating a liquid crystal display according to an embodiment.

Referring toFIG. 1, a liquid crystal display may include a liquid crystal display panel100, a backlight unit200, an upper cover410and a lower cover420.

The liquid crystal display panel100may have a rectangular plate shape with long and short sides. The liquid crystal display panel100may have a display region for displaying images and a non-display region around the display region. Also, the liquid crystal display panel100may include a first substrate110, a second substrate120facing the first substrate110and a liquid crystal layer (not shown) between the first substrate110and the second substrate120. Also, polarizing film (not shown) may be attached on both sides of the liquid crystal display panel100, i.e., on outer surfaces of the first substrate110and the second substrate120.

A plurality of pixels (not shown) arranged in a matrix may be provided on the first substrate110. Each pixel may include a plurality of subpixels. Each subpixel may have a different color. For example, each subpixel may have one of red, green, blue, cyan, magenta or yellow colors. Accordingly, light emitted from each subpixel may have one of the red, green, blue, cyan, magenta or yellow colors. Also, each of the subpixels may include a gate line (not shown), a data line DL (not shown) crossing the gate line such that the data line DL may be insulated from the gate line, and a pixel electrode (not shown). Also, each subpixel may include a thin film transistor (not shown) electrically coupled to the gate line and the data line DL electrically coupled corresponding to the pixel electrode. The thin film transistor may switch a driving signal supplied to the corresponding pixel electrode.

In the non-display region of the first substrate110, a sealing layer (not shown) that attaches the first substrate110and the second substrate120together may be provided.

The second substrate120may include a common electrode (not shown) facing the pixel electrode (not shown).

The liquid crystal layer may be arranged in a predetermined direction due to a voltage applied to the pixel electrode and the common electrode in common. The liquid crystal layer may display an image of the liquid crystal display panel100by adjusting transmittance of the light supplied from the backlight unit200.

Meanwhile, in the non-display region, a signal input pad (not shown) may be arranged on an outside surface of any one of the first substrate110or the second substrate120. The signal input pad may be coupled to a flexible circuit board140with a driver IC11mounted thereon, and the flexible circuit board140may be coupled to an outside circuit module (not shown). The driver IC141may receive control signals input from the outside circuit module, and in response to the control signals, the driver IC141may output a driving signal to the thin film transistor.

The backlight unit200may be disposed on a direction opposite to a light emitting direction of the liquid crystal display panel100. The backlight unit200may include a light guide plate210, a light source unit220including a plurality of light sources, an optical member230and a reflection sheet240.

The light source unit220may have a plurality of light sources221, for example, a plurality of light-emitting diodes are mounted on a printed circuit board222.

Here, the light sources221may emit light having the same colors. For example, the light sources221may emit a white light.

Also, the light sources221may emit light having different colors. For example, a portion of the light sources221may release a red light, another portion of the light sources221may release a green light, and remaining may release a blue light.

The light source unit220may be disposed to face any one of side surfaces of the light guide plate210. As a result, the light that is used to display an image by the liquid crystal display panel100may be provided through the light guide plate210.

The optical member230may be provided between the light guide plate210and the liquid crystal display panel100. The optical member230may adjust the light that is provided from the light source unit220and that is emitted through the light guide plate210. Also, the optical member230may include a diffusion sheet236, a prism sheet234and a protective sheet232, the diffusion sheet236, the prism sheet234and the protective sheet232being sequentially stacked.

The diffusion sheet236may diffuse the light that is emitted from the light guide plate210. The prism sheet234may concentrate light that is diffused from the diffusion sheet236in a direction that is vertical to a surface of a liquid crystal display panel100. The light that passes through the prism sheet234, in most cases, may be incident on the liquid crystal display panel100vertically. The protective sheet232may be located on the prism sheet234. The protective sheet232may protect the prism sheet234from an external impact.

In an embodiment, the optical member230is described as including the diffusion sheets236, the prism sheets235and the protective sheets232, but the present inventive concept is not limited thereto. The optical member230may include at least any one of the diffusion sheet236, the prism sheet234and the protective sheet232, and may include a plurality of sheets stacked one over another. Depending on a need, any one of the sheets may be omitted.

The reflection sheet240may be provided on a lower part of the light guide plate210. The reflection sheet240may reflect the light that does not have an emitting direction toward the liquid crystal display panel100among the light emitted from the light source unit220. The reflection sheet240may include a material that reflects light. The reflection sheet240may be located on the lower cover420and reflect the light generated from the light source unit220. As a result, the reflection sheet240may increase the amount of the light provided to the liquid crystal display panel100.

In an embodiment, the example of the light source unit220is arranged to provide light in a direction towards a side surface of the light guide plate210, however, the present inventive concept is not limited thereto. For example, the light source unit220may be arranged to provide light in a direction towards a lower surface of the light guide plate210. Also, the light guide plate210may be omitted from the backlight unit200, and the light source unit220may be provided on a lower part of the liquid crystal display panel100. The light source unit220may emit light that is directly provided to the liquid crystal display panel100.

The upper cover410may be provided on an upper part of the liquid crystal display panel100. The upper cover410may include a display window411that exposes the display region of the liquid crystal display panel100. The upper cover410may support a front edge of the liquid crystal display panel100by being coupled to the lower cover420.

The lower cover420may be provided on a lower part of the backlight unit200. The lower cover420may include a space that can accommodate the liquid crystal display panel100and the backlight unit200. Also, the lower cover420may receive and support the liquid crystal display panel100and the backlight unit200in an inner space by being coupled to the upper cover410.

FIG. 2is a plane view illustrating one pixel of a liquid crystal display panel shown inFIG. 1.FIG. 3is a cross-sectional view along a I-I′ line ofFIG. 2.FIG. 4is a cross sectional view along a II-II′ line ofFIG. 2.FIG. 5is a cross sectional view along a III-III′ line ofFIG. 2.FIG. 6is a plane view for illustrating a layout of color filters.FIG. 7is a plane view for illustrating a form of a light shield maintenance member.

Referring toFIGS. 2 to 7, a liquid crystal display panel may include a first substrate110, a second substrate120facing the first substrate110and a liquid crystal layer LC between the first substrate110and the second substrate120.

The first substrate110may be a thin film transistor array substrate with thin film transistors formed thereon in order to drive liquid crystal molecules of the liquid crystal layer LC.

The first substrate110may include a first base substrate SUB1having a plurality of pixel regions. The pixel regions may include a transmissive light area TLA that allows light to pass through and a non-transmissive light area NTLA that does not allow light to pass through.

The first base substrate SUB1may be a base substrate of a rigid or a flexible type. The base substrate of the rigid type may be one of a glass base substrate, a quartz base substrate, a glass ceramic base substrate or a crystalline structure glass base substrate. The base substrate of the flexible type may be one of a film base substrate that includes an organic polymer or a plastic base substrate. The material applied to the first base substrate SUB1may have a resistance (or a heat resistance) to a high process temperature at the time of manufacture.

A gate line GL may be provided on the first base substrate SUB1of the non-transmissive light area NTLA. The gate line GL may transmit a gate signal and extend in a first direction. A part of the gate line GL may be a first, second, or third gate electrode (not shown).

A light blocking pattern LBP extending in a second direction may be provided on the first base substrate SUB1of the transmissive light area TLA. The second direction may be a direction that crosses the first direction. The light blocking pattern LBP may have a same material as the gate line GL. The light blocking pattern LBP may be electrically insulated from the gate line GL.

A gate insulating layer GI may be provided on the gate line GL and the light blocking pattern LBP. The gate insulating layer GI may include at least one of a silicon oxide SiOx or a silicon nitride SiNx.

First to third semiconductor layers SA1, SA2and SA3may be provided on the gate insulating layer GI of the non-transmissive light area NTLA. Meanwhile, although not shown in the drawings, an ohmic contact layer may be provided on surfaces of the first to third semiconductor layers SA1, SA2and SA3.

A data line DL, a reference voltage line VL, first to third source electrodes SE1, SE2and SE3and first to third drain electrodes DE1, DE2and DE3may be provided on the gate insulating layer GI and the first to third semiconductor layers SA1, SA2and SA3.

The data line DL may extend in the second direction from one side of each of the pixel regions and may be coupled to an external driving circuit.

The reference voltage line VL may extend in the second direction and may overlap the light blocking pattern LBP.

A first protective layer PSV1may be formed on the data line DL, the reference voltage line VL, the first to third source electrodes SE1, SE2and SE3and the first to third drain electrodes DE1, DE2and DE3. The first protective layer PSV1may include at least one of the silicon oxide SiOx or the silicon nitride SiNx.

A color filter CF may be provided on the first protective layer PSV1. The color filter CF may include an organic material and may have a flat surface. The color filter CF may have one of red, green or blue colors, but the present inventive concept is not limited hereto. For example, the color filter CF may have one of cyan, magenta or yellow colors.

The color filter CF may be provided corresponding to each of the subpixel regions. For example, a red color filter RCF, a green color filter GCF and a blue color filter BCF may be sequentially provided at a red subpixel region, a green sub pixel region and a blue sub pixel region.

The color filters CF may have a substantially rectangular shape with a long side and short side. The color filters CF may have a recessed portion in which a part of a long side corresponding to the non-transmissive light area NTLA may be removed. That is, the shape may be such that the part of the long side may be recessed in a direction going away from the adjacent color filter CF from one side.

Thus, an overlap length of adjacent color filters at a region corresponding to the transmissive light areas TLA is longer than that in the non-transmissive light area NTLA. At an recess portion RP corresponding to the non-transmissive light area NTLA where the color filter is chamfered or trimmed, the adjacent color filters CF may not overlap each other. The color filter may have open portions OP. The pixel electrode may be connected to respective drain electrode through the open portions.

Therefore, surface texturing due to the overlapping of the color filters CF on the non-transmissive light area NTLA may decrease. Particularly, a region where the adjacent color filters CF do not overlap, that is, a surface of the recess portion RP where the chamfered or trimmed shape is provided may not have a step portion. The recess portion RP may have a trapezoidal shape in which a long base is closer to the pixel edge than a short base. The long base and the short base may be substantially parallel to the pixel edge.

A second protective layer PSV2may be provided on the color filter CF. The second protective layer PSV2may prevent the color filter CF from being exposed. The second protective layer PSV2may include a same material as the first protective layer PSV1. That is, the second protective layer PSV2may include at least one of the silicon oxide SiOx or the silicon nitride SiNx.

A first pixel electrode PE1may be provided on the second protective layer PSV2of the transmissive light area TLA. The first pixel electrode PE1may include a transparent conductive oxide. The transparent conductive oxide may be one of indium tin oxide (ITO), indium zinc oxide (IZO), aluminum zinc oxide (AZO), gallium doped zinc oxide (GZO), zinc tin oxide (ZTO), gallium tin oxide (GTO) or fluorine doped tin oxide (FTO).

The first pixel electrode PE1may be coupled to the first drain electrode DE via contact holes that pass through the first protective layer PSV1, the color filter layer CF and the second protective layer PSV2.

The first pixel electrode PE1may have a hexagonal shape. In more detail, the first pixel electrode PE1may have six sides. That is, the first pixel electrode PE1may include a first side and a second side parallel to one side of the pixel region, a third side and a fourth side extending from one side of the first side and the second side, tilted with respect to the first side and the second side and parallel to each other, and a fifth side and a sixth side coupling the first and second sides to the third and fourth sides and parallel to each other. In an embodiment, lengths of the first to sixth sides may be the same.

The first pixel electrode PE1may have an open portion having a rhombus shape at a center and a coupling portion crossing the open portion. The coupling portion may overlap the reference voltage line VL.

A third protective layer PSV3may be provided on the first pixel electrode PE1. That is, the third protective layer PSV3may cover the first pixel electrode PE1. Also, the third protective layer PSV3may include a same material as the first protective layer PSV1. That is, the third protective layer PSV3may include at least one of silicon oxide SiOx or silicon nitride SiNx.

A second pixel electrode PE2may be provided on the third protective layer PSV3of the transmissive light region TLA. The second pixel electrode PE2may include a same material as the first pixel electrode PE1.

Also, the second pixel electrode PE2may have a plate shape and may cover most of the pixel region. The second pixel electrode PE2may include a first sub-pixel electrode SPE1having a rhombus shape and a second sub-pixel electrode SPE2surrounding the first sub-pixel electrode SPE1. The first sub-pixel electrode SPE1and the second sub-pixel electrode SPE2may be spaced apart from each other.

An edge region of the first sub-pixel electrode SPE1may overlap the first pixel electrode PE1. The first sub-pixel electrode SPE1may include a cross-shaped stem portion SPE1-1including a horizontal stem portion and a vertical stem portion and a plurality of first branch portions B1extending from the stem portion SPE1-1. Also, the first sub-pixel electrode SPE1may be coupled to the first pixel electrode PE1via a contact hole passing through the third protective layer PSV3.

The first sub-pixel electrode SPE1may be divided into four sub-regions by the cross-shaped stem portion SPE1-1. Also, the first branch portions B1may be provided at the sub-regions. An angle that the first branch portions B1may form with the stem portion SPE1-1may be approximately 35 degrees to 55 degrees.

An inner edge region of the second sub-pixel electrode SPE2may overlap the first pixel electrode PE1. The second sub-pixel electrode SPE2may be spaced apart from the first sub-pixel electrode SPE1and may surround the first sub-pixel electrode SPE1. The second sub-pixel electrode SPE2may be coupled to the second drain electrode DE2via the contact hole passing through the first protective layer PSV1, the color filter layer CF, the second protective layer PSV2and the third protective layer PSV3.

Also, the second sub-pixel electrode SPE2may include a peripheral portion SPE2-1having a substantially rectangular shape and a plurality of second branch portions B2extending from the peripheral portion SPE2-1. The angle that the second branch portions B2form with the peripheral portion SPE2-1may be approximately 35 degrees to 55 degrees.

A black column spacer BCS may be provided at regions other than the transmissive light region of the third protective layer PSV3. The black column spacer BCS may be provided on the third protective layer PSV3of the region between the non-transmissive region NTLA and the adjacent pixel regions.

The black column spacer BCS may include a light blocking portion that blocks light and surrounding the transmissive light area, and a cell gap retaining portion MCS that maintains a space between the first substrate110and the second substrate120and disposed at the non-transmissive light area. The light blocking portion LBP may block light by being provided between the adjacent transmissive light areas.

The light blocking portion LBP provided on an upper part of an overlapping region OLP where the adjacent color filters CF overlap may maintain a space between the first substrate110and the second substrate120as in the case of the cell gap retaining portion MCS. The region that the adjacent color filters CF overlap each other has an elevated top surface as compared to the other region, and, as a result, the light blocking portion LBP may maintain the cell gap.

Meanwhile, the light blocking portion LBP that corresponds to the recess portion RP where a chamfered or trimmed shape is provided among the light blocking portion LBP may not have an elevated surface. Consequently, a height difference between the light blocking portion LBP and the cell gap retaining portion MCS may be maximized. As a result, AUA defects may be prevented at the recess portion RP where the chamfered or trimmed shape is provided.

The cell gap retaining portion MCS may be provided at a part of the non-transmissive light area NTLA and may have an elevated surface that contacts the second substrate. The cell gap retaining portion MCS may maintain a space between the first substrate110and the second substrate120.

The second substrate120may be a facing substrate facing the first substrate110. The second substrate120may include a second base substrate SUB2and a common electrode CE.

The second base substrate SUB2may include the same material as the first base substrate SUB1.

The common electrode CE may be provided on the second base substrate SUB2. The common electrode CE may have a plate shape at the pixel region.

The common electrode CE may include the same material as the first pixel electrode PE1and the second pixel electrode PE2. That is, the common electrode CE may include the transparent conductive oxide.

An over coat layer (not shown) may be provided between the second base substrate SUB2and the common electrode CE. The over coat layer may be disposed on a side in a direction facing the first substrate110of the second base substrate SUB2. The over coat layer may flatten a surface of the second base substrate SUB2.

The liquid crystal layer LC may include a plurality of liquid crystal molecules having a dielectric anisotropy. The liquid crystal molecules may be provided between the first substrate110and the second substrate120. For example, the liquid crystal molecules may be vertically oriented liquid crystal molecules arranged in a direction vertical to the two substrates110and120between the first substrate110and the second substrate120. If an electric field is applied between the first substrate110and the second substrate120, the liquid crystal molecules may allow light to pass through or block the light by rotating in a predetermined direction between the first substrate110and the second substrate120. Here, the term rotation refers to the liquid crystal molecules lie down in a direction parallel to the first substrate110or the second substrate120. It may also mean that the liquid crystal molecules change the orientation by the electric field.

The liquid crystal display may improve qualities of display by preventing AUA defects.