Liquid crystal display

A liquid crystal display device includes a display panel including: a lower display substrate on which a plurality of pixel electrodes are disposed in a matrix and data lines extend in a column direction between adjacent pixel electrodes; an upper display substrate on which a common electrode is disposed; and a liquid crystal layer disposed between the lower display substrate and the upper display substrate and including liquid crystal molecules. The display panel includes a plurality of unit pixels, each unit pixel including pixels having different colors, and each pixel including one of the pixel electrodes. A gap between neighboring unit pixels is larger than a gap between neighboring pixel electrodes within each unit pixel, and a data line positioned between the neighboring unit pixels has a portion having a width larger than that of a data line positioned between the neighboring pixel electrodes within each unit pixel.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2015-0003663 filed in the Korean Intellectual Property Office on Jan. 9, 2015, the entire contents of which are incorporated herein by reference.

BACKGROUND

(a) Technical Field

The present invention relates to a liquid crystal display.

(b) Description of the Related Art

Liquid crystal displays (LCD) are currently one of most widely used flat panel displays (FPDs). Liquid crystal displays include two display substrates and a liquid crystal layer interposed therebetween. The display substrates include field generating electrodes such as a pixel electrode, a common electrode, and the like, formed thereon. In an LCD, a voltage is applied to a field generating electrode to generate an electric field in a liquid crystal layer, whereby orientation of liquid crystal molecules of the liquid crystal layer is determined and polarization of incident light is controlled to display an image.

Among LCDs is a vertically aligned mode LCD in which liquid crystal modules are aligned such that a longer axis thereof is perpendicular to a display panel in a state in which a field is not applied. In order to secure a wide viewing angle, the vertically aligned mode LCD uses a scheme of forming a cutout portion such as a fine slit, or the like, in a field generating electrode to form a plurality of domains in which liquid crystal molecules are controlled to be oriented in different directions, or the like. Also, in order to make lateral visibility approximate to front visibility, a method of dividing a single subpixel into two sections and applying different voltages thereto to differentiate transmittance has been proposed.

Recently, LCDs have been increased in size, and curved display panels that increase the engagement (or immersion) and presence of viewers have been developed. LCDs employing such a curved display panel have emerged. However, in a curved display panel, a lower display substrate and an upper display substrate may be misaligned, generating texture to due to interference between adjacent pixels to limit a reduction in a width of a light blocking member.

SUMMARY

A liquid crystal display device having excellent display quality is provided.

A liquid crystal display device having advantages of reducing texture generated as lower and upper display substrates are misaligned in a curved display panel and preventing generation of spots due to a coupling effect based on capacitance between a pixel electrode and a data line is also provided.

In one aspect, a liquid crystal display device includes a display panel including: a lower display substrate on which a plurality of pixel electrodes are disposed in a matrix and data lines extend in a column direction between adjacent pixel electrodes; an upper display substrate on which a common electrode is disposed; and a liquid crystal layer disposed between the lower display substrate and the upper display substrate and including liquid crystal molecules. The display panel includes a plurality of unit pixels, each unit pixel including pixels having different colors, and each pixel including one pixel electrode of the plurality of pixel electrodes. A gap between neighboring unit pixels is larger than a gap between neighboring pixel electrodes within the same unit pixel, and a data line positioned between the neighboring unit pixels has a portion having a width larger than that of a data line positioned between the neighboring pixel electrodes within each unit pixel.

A distance between a left data line and a pixel electrode adjacent to the data line positioned between the neighboring unit pixels and a distance between a right data line and the pixel electrode may be substantially equal.

The portion having a larger width of the data line positioned in the boundary between the neighboring unit pixels may have a ring shape with both ends rounded.

The portion having a larger width of the data line positioned in the boundary between the neighboring unit pixels may have a ring shape with both ends angular.

The portion having a larger width of the data line positioned in the boundary between the neighboring unit pixels may be formed as a solid body.

The portion having a larger width of the data line positioned in the boundary between the neighboring unit pixels may be continuously formed across the plurality of pixel electrodes in a column direction.

The portion having a larger width of the data line positioned in the boundary between the neighboring unit pixels may be formed to be discontinuous at every portion between the pixels.

Each pixel electrode may include a first subpixel electrode and a second subpixel electrode, each of the first and second subpixel electrodes may include a plurality of subregions in which tilting directions of liquid crystal molecules may be differently controlled, and directions in which the liquid crystal molecules are controlled may be substantially the same in the corresponding subregions of the pixel electrodes within each unit pixel.

Directions in which the liquid crystal molecules are controlled may be substantially opposite in corresponding subregions of the pixel electrodes adjacent to the boundary between the neighboring unit pixels.

The first subpixel electrode may include first, second, third, and fourth subregions sequentially from an upper side, and a direction in which the liquid crystal molecules are controlled in the first and second subregions and a direction in which the liquid crystal molecules are controlled in the third and fourth subregions may be substantially opposite.

The second subpixel electrode may include first, second, third, and fourth subregions sequentially from an upper side, and a direction in which the liquid crystal molecules are controlled in the first and second subregions and a direction in which the liquid crystal molecules are controlled in the third and fourth subregions may be substantially opposite.

A direction in which the liquid crystal molecules are controlled in the first and second subregions of the first subpixel electrode and a direction in which the liquid crystal molecules are controlled in the first and second subregions of the second subpixel electrode may be substantially the same.

Each of the first subpixel electrode and the second subpixel electrode may include an upper electrode and a lower electrode connected to each other, each of the upper electrode and the lower electrode each may include a horizontal stem portion, a vertical stem portion, and a plurality of fine branch portions slantingly extending from the horizontal stem portion or the vertical stem portion, and the horizontal stem portion forms the boundary between two neighboring subregions.

In another aspect, a liquid crystal display device includes a display panel including: a lower display substrate on which a plurality of pixel electrodes are disposed in a matrix and data lines extend in a column direction between adjacent pixel electrodes; an upper display substrate on which a common electrode is disposed; and a liquid crystal layer disposed between the lower display substrate and the upper display substrate and including liquid crystal molecules. The display panel may include a plurality of unit pixels, each unit pixel including pixels having different colors, and each pixel including one pixel electrode of the plurality of pixel electrodes, a gap between pixel electrodes adjacent to the boundary between unit pixels neighboring in a row direction is larger than a gap between neighboring pixel electrodes within each unit pixel, and a wing is connected to a side, which is adjacent to the boundary, of the pixel electrode that is adjacent to the boundary.

A distance between the pixel electrode adjacent to the boundary and a data line adjacent to a side of the pixel electrode where the wing is not connected and a distance between the wing connected to the pixel electrode and the data line positioned in the boundary may be substantially equal.

One wing adjacent to the boundary may be connected to the pixel electrode.

A plurality of wings may be connected to the pixel electrode adjacent to the boundary.

The wing may be formed to be substantially parallel to the data line positioned in the boundary.

The wing may be formed on the same layer as that of the pixel electrode, and may be formed of the same material as that of the pixel electrode.

The wing may be covered by a light blocking member.

According to an embodiment of the present invention, generation of spots due to coupling between a pixel electrode and a data line in a pixel adjacent to the boundary of a unit pixel may be suppressed or prevented, while an aperture ratio of the curved display panel increases since a light blocking member is differentially applied.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like reference numerals designate like elements throughout the specification. It will be understood that when an element such as a layer, film, region, or substrate is referred to as being “on” another element, it can be directly on the other element, or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. Throughout the specification, “overlap” refers to “overlap viewed in the plan view”, unless otherwise mentioned.

A liquid crystal display (LCD) device according to an example embodiment will be described in detail with reference to the accompanying drawings.

FIG. 1is a view illustrating a pixel of a liquid crystal display device according to an example embodiment, andFIG. 2is an equivalent circuit diagram of a pixel of the LCD device according to an example embodiment.

Referring toFIG. 1, an LCD device according to an example embodiment includes a plurality of pixels PX arranged in a matrix direction. A pixel PX is a minimum unit area used in displaying an image, and one pixel PX may display any one of a set of primary colors used to display an image. For example, one pixel may display any one of a red, green, or blue color, which are three primary colors of light. A pixel is called a red pixel (R), a green pixel (G), or a blue pixel (B) depending on the color displayed by the pixel, and the colored pixels R, G, and B are repeatedly disposed in particular order. In the present disclosure, a set of pixels that includes at least one of each of the three types of colored pixels R, G, and B is called a unit pixel PXU. According to example embodiments, there may also be a pixel displaying a white color (a white pixel W), and the unit pixel may further include the white pixel W.

Pixels PX are disposed at equal gaps within the unit pixel PXU, but are disposed at a larger gap between unit pixels PXU. For example, as illustrated inFIG. 1, when a red pixel R, a green pixel G, and a blue pixel B are disposed in this order, a gap g1between the red pixel R and the green pixel G and a gap g2between the green pixel G and the blue pixel B within the unit pixel PXU are equal, while a gap g3between the blue pixel B and the red pixel R adjacent between neighboring unit pixels PXU is greater than g1or g2. The arrangement order of the colored pixels R, G, and B is merely illustrative and may be variously modified.

One pixel PX may include a first subpixel PXA and a second subpixel PXB. The first subpixel PXa and the second subpixel PXB may display an image according to different gamma curves with respect to one input image signal, or may display an image according to the same gamma curve. That is, with respect to one input image signal, the first subpixel PXa and the second subpixel PXb of one pixel PX may display images having different brightness to enhance lateral visibility. The first subpixel PXa and the second subpixel PXb may have the same area or different areas. The pixel PX including the first subpixel PXa and the second subpixel PXB may have various circuit structures and dispositions to display an image having different brightness.

Referring toFIG. 2, the LCD device according to an example embodiment includes signal lines such as a gate line121, a data line171, and a reference voltage line172transmitting a reference voltage, and the like, and a pixel PX connected thereto.

Each pixel PX includes first and second subpixels PXa and PXb. The first subpixel PXa includes a first switching element Qa and a first liquid crystal capacitor Clca, and the second subpixel PXb includes a second and third switching elements Qb and Qc and a second liquid crystal capacitor Clcb. The first switching element Q1and the second switching element Qb are connected to the gate line121and the data line171, respectively, and the third switching element Qc is connected to an output terminal of the second switching element Qb and the reference voltage line172. An output terminal of the first switching element Qa is connected to the first liquid crystal capacitor Clca, and the output terminal of the second switching element Qb is connected to the second liquid crystal capacitor Clcb and an input terminal of the third switching element Qc. A control terminal of the third switching element Qc is connected to the gate line121, an input terminal thereof is connected to the second liquid crystal capacitor Clcb, and an output terminal thereof is connected to the reference voltage line172.

Referring to an operation of the pixel PX illustrated inFIG. 2, first, when a gate ON voltage is applied to the gate line121, the first switching element Qa, the second switching element Qb, and the third switching element Qc connected to the gate line121are turned on. Thus, a data voltage applied to the data line171is applied to the first liquid crystal capacitor Clca and the second liquid crystal capacitor Clcb, respectively, through the first switching element Qa and the second switching element Qb in the turned-on state, and the first liquid crystal capacitor Clca and the second liquid crystal capacitor Clcb are charged by a difference between the data voltage and the common voltage. Here, the same data voltage is transmitted to the first liquid crystal capacitor Clca and the second liquid crystal capacitor Clcb through the first and second switching elements Qa and Qb, but a charge voltage of the second liquid crystal capacitor Clcb is divided by the third switching element Qc. Thus, because the charge voltage of the second liquid crystal capacitor Clcb is smaller than the charge voltage of the first liquid crystal capacitor Clca, luminance of the two subpixels PXa and PXb may be varied. Thus, when the voltage charged in the first liquid crystal capacitor Clca and the voltage charged in the second liquid crystal capacitor Clcb are appropriately adjusted, an image viewed from the side may approximate to an image viewed from the front side. This means that lateral visibility is enhanced.

In the illustrated example embodiment, the third switching element Qc connected to the second liquid crystal capacitor Clcb and the reference voltage line172is included to vary the voltage charged in the first liquid crystal capacitor Clca and the voltage charged in the second liquid crystal capacitor Clcb, but any other configuration may be provided according to example embodiments. For example, the second liquid crystal capacitor Clcb may be connected to a step-down capacitor. In detail, a third switching element including a first terminal connected to a step-down gate line, a second terminal connected to the second liquid crystal capacitor Clcb, and a third terminal connected to the step-down capacitor may be included to charge a portion of an amount of an electric charge charged in the second liquid crystal capacitor Clcb to the step-down capacitor, whereby charge voltages of the first liquid crystal capacitor Clca and the second liquid crystal capacitor Clcb may be set to be different. In another example, the first liquid crystal capacitor Clca and the second liquid crystal capacitor Clcb may be connected to different data lines to receive different data voltages, whereby charge voltages of the first liquid crystal capacitor Clca and the second liquid crystal capacitor Clcb may be set to be different. According to example embodiments, a single pixel may not be divided into subpixels.

Hereinafter, the LCD device according to an example embodiment will be described in detail with reference toFIGS. 3, 4 and 5.

FIG. 3is a layout view of a pixel of the LCD device according to an example embodiment,FIG. 4is a cross-sectional view of the LCD device ofFIG. 2, taken along line II-II, andFIG. 5is a plan view of a subpixel electrode of the LCD device according to an example embodiment.

The LCD device includes a display panel including the lower display substrate100and the upper display substrate200facing each other, and a liquid crystal layer3positioned between the two display substrates100and200. A plurality of pixels PXs are disposed on the display panel.

First, the lower display substrate100will be described.

A gate conductor including a gate line121and storage electrode lines131and132is formed on an insulating substrate110formed of transparent glass, plastic, and the like.

The gate line121includes a large end portion (not shown) for contacting with a gate electrode and any other layer or an external driving circuit. The gate line121may be formed of an aluminum-based metal such as aluminum (Al), an aluminum alloy, and the like, a silver-based metal such as silver (Ag), a silver alloy, and the like, a copper-based metal such as copper (Cu), a copper alloy, and the like, a molybdenum-based metal such as molybdenum (Mo), a molybdenum alloy, and the like, chromium (Cr), tantalum (Ta), or titanium (Ti). The gate line121may have multilayer structure including at least two conductive films having different physical properties.

The gate line121may extend mainly in a horizontal direction and may be formed to traverse one pixel area having a substantially quadrangular shape horizontally. An upper region of the pixel above the gate line121is a first subpixel region displaying a high gray level and a lower region of the pixel below the gate line121is a second subpixel region displaying a low gray level. The first and second subpixel regions may have a substantially quadrangular shape, and the second subpixel region may be greater than the first subpixel region.

The storage electrode lines131and132may be formed of the same material as that of the gate line121, and may be formed through a simultaneous process with the gate line121.

The storage electrode line131above the gate line121may have a shape surrounding the first subpixel region in a quadrangular shape. A horizontal portion positioned in the uppermost portion of the storage electrode line131having the quadrangular shape may extend, beyond one pixel area, in a horizontal direction so as to be connected to a different layer or an external driving circuit.

The storage electrode line132below the gate line121may have a shape similar to the digital number5in the second subpixel region. For example, the storage electrode line132includes three horizontal portions and two vertical portions connecting the three horizontal portions on the edges thereof, and here, the vertical portions connect only one ends of the horizontal portions. When the first horizontal portion and the second horizontal portion are connected by the first vertical portion on the left, the second horizontal portion and the third horizontal portion are connected by the second vertical portion on the right. The third horizontal portion positioned in the lowermost portion of the storage electrode line132may extend, beyond one pixel area, in a horizontal direction so as to be connected to a different layer or an external driving circuit. The third horizontal portion of the storage electrode line132may be the same as a horizontal portion positioned in the uppermost portion of the storage electrode line131of a different pixel area adjacent in a vertical direction.

A gate insulating layer140is formed on the gate conductor, and a first semiconductor154a, a second semiconductor154b, and a third semiconductor154cmay be formed on the gate insulating layer140. A plurality of resistive contact members163a,165a,163b,165b,163c, and165cmay be formed on the semiconductors154a,154b, and154c. A data conductor including the data line171and the reference voltage line172is formed on the resistive contact members163a,165a,163b,165b,163c, and165c, and the gate insulating layer140.

The data conductor includes the data line171, a first drain electrode175a, a second drain electrode175b, and the reference voltage line172. The data line171extends substantially in the vertical direction along one pixel area, and includes a first source electrode173aand a second source electrode173b. The reference voltage line172includes a third drain electrode175c. The second drain electrode175bis connected to a third source electrode173c, and includes an extending portion.

The reference voltage line172may have a shape similar to the digital number5in each of the first subpixel region and the second subpixel region. For example, the reference voltage line172includes three horizontal portions and two vertical portions connecting the three horizontal portions on the edges thereof, and here, the vertical portions connect only one ends of the horizontal portions. When the first horizontal portion and the second horizontal portion are connected by the first vertical portion on the left, the second horizontal portion and the third horizontal portion are connected on the right. The reference voltage line172may have a shape in which the foregoing shape is reversed left and right according to directions of the pixel electrode formed later. That is, the reference voltage line172may have a shape of the digital number5reversed left to right in each of the first subpixel region and the second subpixel region.

In the reference voltage line172positioned in the first subpixel region, a portion of the third horizontal portion positioned in the lowermost portion may be branched to become a third drain electrode175c.

The first gate electrode124a, the first source electrode173a, and the first drain electrode175amay form one first switching element Qa as a thin film transistor (TFT) together with the first semiconductor154a, and a channel of the TFT is formed in the first semiconductor154apart between the first source electrode173aand the first drain electrode175a. Similarly, the second gate electrode124b, the second source electrode173b, and the second drain electrode175bform one second switching element Qb together with the second semiconductor154b, and the third gate electrode124c, the third source electrode173c, and the third drain electrode175cform one third switching element Qc together with the third semiconductor154c.

A first passivation layer180pis formed on exposed portions of the data conductor and the semiconductors154a,154b, and154c. The first passivation layer180pmay include an inorganic insulating layer such as a silicon nitride (SiNx) or a silicon oxide (SiOx). When a second passivation layer180qis a color filter, the first passivation layer180pmay prevent pigment of the color filer230from being introduced to the exposed portions of the semiconductors154a,154b, and154c.

The second passivation layer180qis formed on the first passivation layer180p. The second passivation layer180qmay be omitted. The second passivation layer180qmay be a color filter. When the second passivation layer180qis a color filter, the second passivation layer180qmay uniquely display one primary color.

A first contact hole185aand a second contact hole185bexposing the first drain electrode175aand the second drain electrode175bare formed in the first passivation layer180pand the second passivation layer180q, respectively.

A plurality of pixel electrodes191may be formed on the second passivation layer180q, and an alignment layer11may be formed on the pixel electrode191. Each pixel electrode191includes a first subpixel electrode191aand a second subpixel electrode191b, and the first subpixel electrode191aand the second subpixel electrode191bare separated with the gate line121interposed therebetween. The pixel electrode191may be formed of a transparent conductive material (TCO) such as an indium tin oxide (ITO) or an indium zinc oxide (IZO), or may be formed of a reflective metal such as aluminum (Al), silver (Ag), chromium (Cr), or an alloy thereof. Each pixel electrode191is illustrated as being connected to the data line171on the left side thereof, but may also be connected to the data line171on the right side thereof. The subpixel electrodes191aand191bwill be described in more detail with reference toFIG. 5.

Although not shown, a shielding electrode may be formed to overlap with the data line171along the data line171positioned between the pixel electrodes191adjacent in the horizontal direction. In this case, when a voltage the same as a voltage applied to a common electrode270is applied to the shielding electrode, an electric field is not generated between the shielding electrode and the common electrode270. The liquid crystal molecules present therebetween are in a vertically aligned state, preventing light leakage between the pixel electrodes191and light reflection by the data line171. The shielding electrode may be formed of a material that is the same as that of the pixel electrode191on the second passivation layer180q.

Hereinafter, the upper display substrate200will be described.

A light blocking member220formed of transparent glass, plastic, or the like, is formed on an insulating substrate210. The light blocking member220is also called a black matrix and prevents light leakage and light reflection. The light blocking member220is formed to overlap with the gate line121, the switching elements Qa, Qb, and Qc, and the like, in the direction in which the gate line121extends. The light blocking member220may also be formed to overlap with the data line171in the direction in which the data line extends, so as to have a lattice structure having an opening (so that the light blocking member does not cover the first and second subpixel electrodes191aand191b) corresponding to the region (namely, the subpixel region) in which light is emitted to display an image. In a case in which the shielding electrode is formed to overlap with the data line171, the light blocking member220extending along the data line171may be omitted. The light blocking member220may be formed of a material not allowing light to be transmitted therethrough.

A color filter230is also formed on the substrate210. In a case in which the second passivation layer180qof the lower display substrate100is a color filter, the color filter230of the upper display substrate200may be omitted. The light blocking member220of the upper display substrate200may also be formed on the lower display substrate100.

An overcoat250may be formed on the color filter230and the light blocking member220to prevent the color filter230from being exposed and provide a flat surface. The overcoat250may be omitted. A common electrode270is formed on the overcoat250, and an alignment layer21may be formed on the common electrode270.

The liquid crystal layer3positioned between the lower display substrate100and the upper display substrate200includes liquid crystal molecules31. The liquid crystal molecules31may have negative dielectric anisotropy, and are aligned such that a longer axis thereof is perpendicular to surfaces of the two display substrates100and200in a state in which an electric field is not generated in the liquid crystal layer3. The first subpixel electrode191aand the second subpixel electrode191b, to which a data voltage is applied, generate an electric field together with the common electrode270of the upper display substrate200, thereby determining orientation of the liquid crystal molecules31of the liquid crystal layer3between the two electrodes191and270. Luminance of light passing through the liquid crystal layer3may vary depending on the determined orientation of the liquid crystal molecules31.

The first and second subpixel electrodes191aand191bwill be described in detail with reference toFIG. 5.

The first subpixel electrode191ahas an overall quadrangular shape and includes an upper electrode191a1and a lower electrode191a2neighboring the upper electrode191a1with a gap95interposed therebetween. The upper electrode191a1and the lower electrode191a2may have the substantially same size (in particular, area). The upper electrode191a1and the lower electrode191a2may be electrically connected through at least one connection portion192. A connection portion192may be formed on the same layer as that of the first subpixel electrode191aand formed of the same material as that of the first subpixel electrode191a. As illustrated, the connection portion192may be positioned substantially in the center of the first subpixel electrode191a, or may be positioned substantially in left and/or right edge of the first subpixel electrode191a.

The upper electrode191a1includes at least one horizontal stem portion195aand at least one vertical stem portion197aconnected thereto. The vertical stem portion197amainly extends in a vertical direction, and defines one edge, for example, a left edge, of the upper unit electrode191a1. The horizontal stem portion195amay extend, starting from substantially the center of the vertical stem portion197a, in a horizontal direction substantially perpendicular to the vertical stem portion197a.

The lower electrode191a2may have a shape substantially horizontally symmetrical to the shape of the upper electrode191a1in a reversed manner (i.e., the lower electrode191a2has substantially the same shape as the upper electrode191a1but positioned in a way that is rotated 180 degrees about a center point as compared to upper electrode191a1). That is, the lower electrode191a2includes at least one horizontal stem portion195band at least one vertical stem portion197bconnected thereto. The vertical stem portion197bextends mainly in a vertical direction and defines one edge, for example, a right edge, of the lower unit electrode191a2. The horizontal stem portion195bmay extend, starting from the substantially center of the vertical stem portion197b, in a horizontal direction substantially perpendicular to the vertical stem portion197b.

Lengths of the horizontal stem portions195aand195bmay be greater than those of the vertical stem portions197aand197b.

Each of the horizontal stem portions195aand195bmay include a portion having a changed width, and the horizontal stem portions195aand195bmay have the largest width in a position connected to the vertical stem portions197aand197b. As for the portion having a changed width of each of the horizontal stem portions195aand195b, the width may decrease, starting from the portion connected to the vertical stem portions197aand197b, in a direction away from the vertical stem portions197aand197b.

Each of the vertical stem portions197aand197bmay include a portion having a changed width, and the vertical stem portions197aand197bmay have the largest width in a position connected to the horizontal stem portions195aand195b. As for the portion having a changed width of each of the vertical stem portions197aand197b, the width may decrease, starting from the portion connected to the horizontal stem portions195aand195b, in a direction away from the horizontal stem portions195aand195b.

The first subpixel electrode191ais divided into a plurality of subregions R1, R2, R3, and R4by the horizontal stem portions195aand195b, the vertical stem portions197aand197b, and a gap95. The horizontal stem portions195aand195b, the vertical stem portions197aand197b, and a gap95form boundaries between the neighboring subregions R1, R2, R3, and R4.

The first subpixel electrode191aincludes a plurality of fine branch portions199formed in each of the subregions R1, R2, R3, and R4. The fine branch portions199may slantingly extend outwardly from the horizontal stem portions195aand195bor the vertical stem portions197aand197b. Fine slits91are positioned between neighboring fine branch portions199, from which the electrodes have been removed.

The fine branch portions195of the different subregions R1, R2, R3, and R4of one first subpixel electrode191amay extend in different directions. In particular, the fine branch portions199of the adjacent subregions R1, R2, R3, and R4on opposite sides of horizontal stem portions195aand195bor gap95may be at an angle about 90 degrees or 180 degrees. In each of the subregions R1, R2, R3, and R4, the directions in which the fine branch portions199extend may be uniform. In detail, among the subregions R1and R2defined by the horizontal stem portion195aand the vertical stem portion197a, the fine branch portions199of the upper subregion R1may extend right upwardly from the horizontal stem portion195aor the vertical stem portion197a, and the fine branch portions199of the lower subregion R2may extend right downwardly from the horizontal stem portion195aor the vertical stem portion197a. Also, among the subregions R3and R4defined by the horizontal stem portion195band the vertical stem portion197b, the fine branch portions199of the upper subregion R3may extend left upwardly from the horizontal stem portion195bor the vertical stem portion197b, and the fine branch portions199of the lower subregion R4may extend left downwardly from the horizontal stem portion195bor the vertical stem portion197b. A portion of the fine branch portions199of the subregion R4is connected to an extending portion of the first subpixel electrode191ato receive a voltage from the first drain electrode175aconnected through the first contact hole185a(please refer toFIGS. 1 and 2).

The second subpixel electrode191bmay have a size different from that of the first subpixel electrode191a, and may have the substantially same structure as that of the first subpixel electrode191a. Thus, the description of the first subpixel electrode191awill replace a detailed description of the second subpixel electrode191b.

Referring toFIGS. 3 through 5, a liquid crystal layer3positioned in one pixel PX includes a plurality of domains in which directions in which the liquid crystal molecules31are tilted are different when an electric field is generated in the liquid crystal layer3, thereby achieving a wide viewing angle. The directions in which the liquid crystal molecules31are tilted may be uniform in each domain, and the particular direction may be referred to as a behavior direction of the liquid crystal molecules31. In this disclosure, a behavior direction of the liquid crystal molecules31in each domain may be referred to simply as a domain direction.

In one pixel PX, domains of the liquid crystal layer3may correspond to a plurality of subregions R1to R4of the first subpixel electrode191aand the plurality of subregions R1to R4of the second subpixel electrode191b, respectively. For example, in a case in which a pixel electrode includes eight subregions, namely, four subregions R1to R4of the first subpixel electrode191aand four subregions R1to R4of the second subpixel electrode191b, the liquid crystal layer3corresponding thereto may have eight domains in each pixel PX.

For a fast response speed, the liquid crystal molecules31of each domain may be initially aligned at a pretilt angle in each behavior direction in a state in which an electrical field is not present in the liquid crystal layer3. In this manner, in order to allow the liquid crystal molecules31to have a pretilt angle at an initial stage, an alignment layer having several orientation directions may be used, or the liquid crystal layer3or the alignment layer may include an alignment assistant for pretilting of the liquid crystal molecules31. In a case in which the alignment layer forms pretilting of the liquid crystal molecules31, light such as ultraviolet ray may be slantingly irradiated to control an initial orientation direction and an orientation angle of the liquid crystal molecules31. In one pixel, directions in which liquid crystal molecules31are tilted are different in each domain, and thus, pretilt directions are also different in each domain.

Operations of the LCD device according to an example embodiment will be described with reference toFIGS. 3 through 5.

When a gate ON voltage is applied to the gate electrodes of the switching elements Qa and Qb to turn on the switching elements Qa and Qb, a data voltage is applied to the first and second subpixel electrodes191aand191b. The first and second subpixel electrodes191aand191b, to which the data voltage has been applied, and the common electrode270to which a common voltage has been applied, generate an electric field together in the liquid crystal layer3.

The electric field includes a vertical component substantially perpendicular to the surfaces of the display substrates100and200, and the liquid crystal molecules31tend to be tilted in a direction substantially parallel to the surfaces of the display substrates100and200by the vertical component of the electric field. A fringe field is formed between the edges of the fine branch portions199and the horizontal stem portions195aand195band the vertical stem portions197aand197bof the first and second subpixel electrodes191aand191band the common electrode270, and thus, the liquid crystal molecules31are substantially tilted toward the connection portions of the horizontal stem portions195aand195band the vertical stem portions197aand197band in a direction substantially parallel to a length direction of the fine branch portions199. Thus, a plurality of domains in which directions in which the liquid crystal molecules31are tilted are different are formed in the liquid crystal layer3of one pixel PX. In this manner, the means for controlling the liquid crystal molecules31of the liquid crystal layer3to be tilted in different directions is called a domain dividing unit.

Referring toFIG. 5, the liquid crystal molecules31corresponding to the subregion R1is tilted substantially in a first direction dr1, and the liquid crystal molecules31corresponding to the subregion R2is tilted substantially in a second direction dr2. The liquid crystal molecules31corresponding to the subregion R3is tilted substantially in a third direction dr3, and the liquid crystal molecules31corresponding to the subregion R4is tilted substantially in a fourth direction dr2. The first to fourth directions dr1to dr4are behavior directions of the liquid crystal molecules31. For example, at a left viewing angle, the domains in which the liquid crystal molecules31are tilted in the first and second directions dr1and dr2are mainly visible, and at the right viewing angle, the domains in which the liquid crystal molecules31are tilted in the third and fourth directions dr3and dr4are mainly visible. Of course, in the front, all the domains are visible regardless of domain direction. Visualized viewing angles of a pair of domains in the first and second directions and a pair of domains in the third and fourth directions are different on left and right sides thereof, it may be expressed that the directions dr1and dr2of the pair of first and second domains and the directions dr3and dr4of the pair of third and fourth domains are staggered.

FIG. 6is a view illustrating domain directions in adjacent pixels of the LCD device according to an example embodiment.

Likewise as inFIG. 1, it illustrated that three pixels PX form each of unit pixels PXU1and PXU2and six pixels PX are adjacent in the horizontal direction. Each of the pixels PX includes a first subpixel PXa and a second subpixel PXb, and each of the first and second subpixels PXa and PXb is divided into four domains.

In the first unit pixel PXU1, the pixels PX are arranged in order of a red pixel R1, a green pixel G1, and a blue pixel B1from the left. The pixels PX of the first unit pixel PXU1have the same domain direction. For example, when the red pixel R1has the foregoing domain directions dr1to dr4, the green pixel G1and the blue pixel B1have the same domain directions dr1to dr4.

In the second unit pixel PXU2adjacent to the first unit pixel PXU1, the pixels PX are arranged in order of a red pixel R2, a green pixel G2, and a blue pixel B2from the left. The pixels PX of the second unit pixel PXU2have the same domain direction. However, the pixels PX of the second unit pixel PXU2have domain directions different from those of the pixels PX of the first unit pixel PXU1. That is, the pixels PX of the two adjacent unit pixels PXU1and PXU2have domain directions symmetrical with respect the boundary of two unit pixels PXU1and PXU2.

In a case in which a display panel is a curved display panel, the lower display substrate100and the upper display substrate200have different curvatures. Thus, if the domain directions of adjacent pixels are different, pretilting directions of the lower display substrate100and the upper display substrate200are changed, generating texture (a dark portion) in both left and right end portions of the pixels. Thus, such texture is suppressed or covered by increasing a gap between pixels and expanding the light blocking member220overlapping with the data line171between mutually adjacent pixels. However, as in the example embodiment of the present disclosure, when the domain directions of the pixels of the unit pixels PXU1and PXU2are the same, because the pretilting directions of the pixels are not different, the generation of texture is reduced. Thus, the width of the light blocking member220overlapping with the data line171may be reduced and the gap between adjacent pixels may be reduced, whereby an aspect ratio may increase to increase transmission efficiency.

However, the two pixels B1and R2adjacent to the boundary between the two neighboring unit pixels PXU1and PXU2have different domain directions, so it is necessary to expand the light blocking member220overlapping with the data line171. Thus, gaps g1and g2between the pixels within the unit pixels PXU1and PXU2are smaller than the gap g3between the pixels within the unit pixels PXU1and PXU2, and a width of the light blocking member220between the pixels within the unit pixels PXU1and PXU2is smaller than a width of the light blocking member between the unit pixels PXU1and PXU2.

In the case in which the domain directions of pixels are the opposite in every unit pixel PXU1and PXU2(which is called a unit pixel stagger structure), the gaps g1and g2between the pixels within the unit pixels PXU1and PXU2and the gap g3between the pixels B1and R2adjacent to the boundary between the unit pixels PXU1and PXU2are different. Thus, in the pixels B1and R2adjacent to the boundary between the unit pixels PXU1and PXU2, a gap between the pixel electrode and the data line on the left side thereof and a gap between the pixel electrode and the data line on the right side thereof may be different. Thus, capacitance between the pixel electrode and the data lines is formed to be different on the left side and the right side of the pixel electrode and a pixel voltage is affected by fluctuation in a data voltage due to the coupling based on the different capacitances. When the pixel voltage is changed according to an influence of the data voltage, spots may be generated and image quality may be degraded.

Thus, the present disclosure provides several schemes for making the gaps between the pixel electrode and the data lines equal. In a case in which the gaps between the pixel electrode and the data lines equal on both sides of the pixel electrode, capacitance between the pixel electrode and data lines on both sides of the pixel electrode may be the same, and thus, coupling effect due to both capacitance may be canceled out, preventing generation of spots.

FIGS. 7 through 12are views illustrating dispositions of pixel electrodes and data lines according to some example embodiments.

Referring toFIG. 7, only pixel electrodes and data lines in two unit pixels PXU1and PXU2adjacent in a horizontal direction are schematically illustrated. As described above, each pixel electrode may include a first subpixel electrode and a second subpixel electrode, and each subpixel electrode may be patterned to have a horizontal stem portion, a vertical stem portion, fine branch portions, and the like, and here, each pixel electrode is briefly illustrated as having a quadrangular shape.

Gaps between pixel electrodes191R1,191G1,191B1;191R2,191G2, and191B2within the unit pixels PXU1and PXU2are equal, and data lines171G1,171B1;171G2, and171B2positioned in the gaps between the pixel electrodes extend as a single body, individually and substantially linearly such as in a general LCD device. A gap between the pixel electrodes191B1and191R2adjacent to the boundary of the neighboring unit pixels PXU1and PXU2is larger than the gaps between the pixel electrodes within the unit pixels. Such characteristics are the same even in the example embodiment ofFIGS. 8 through 12.

As illustrated inFIG. 7, the data line171R2positioned between the unit pixels PXU1and PXU2, namely, between the pixel electrodes191B1and191R2, is formed like a vertically elongated ring. That is, the data line171R2extends as one body in substantially upper and lower sides of the pixel electrodes191B1and191R2in a vertical direction, but bifurcates (like a U-shape) to form two lines in parallel between the pixel electrodes191B1and191R2.

When the data line171R2is formed in this manner, because the width of the data line171R2increases, distances between the data line171R2and the pixel electrodes191B1and191R2may be reduced. According to the example embodiment, by appropriately adjusting the width of the data line171R2, the distances between the pixel electrodes191B1and191R2and the data lines171B1and171R2on the left side thereof and the distances between the pixel electrodes191B1and the191R2and the data lines171R2and171G2on the right side thereof may be substantially equal, and thus, capacitance generated with the data lines on both sides can be substantially equal, preventing generation of spots due to non-uniform coupling on both sides of the pixel electrodes191B1and191R2.

In a case in which the data line171R2is formed as a single linear line like the other data lines171G1,171B1,171G2, and171B2, because the gap between the pixel electrodes191B1and191R2is large, and thus, a distance to at least one of the pixel electrodes191B1and191R2may inevitably become relatively distant. Then, capacitances generated with the data lines on both sides are different due to the difference in the distances between at least one of the pixel electrodes191B1and191R2and the data lines171B1and171R2on the left side thereof and the data lines171R2and171G2on the right side thereof, and as a result, a pixel voltage is changed by a data voltage due to the non-uniform coupling, generating spots.

FIGS. 8 through 10illustrate modified examples of the data line171R2positioned between the neighboring unit pixels PXU1and PXU2.

Referring toFIG. 8, the data line171R2includes a quadrangular ring which is elongated in a vertical direction and hollow in a center area. Compared with the example embodiment ofFIG. 7in which both ends of the ring are rounded, the present example embodiment is slightly different in that both ends of the ring are angular. In this manner, even though the data line171R2is formed as a quadrangular ring, the width of the data line171R2is large so as to reduce distances to the pixel electrodes191B1and191R2on both sides of the data line171R2, thus preventing generation of spots due to non-uniform coupling. The quadrangular ring may be continuously formed across the plurality of pixels in the vertical direction, or alternatively, as illustrated inFIG. 9, a quadrangular ring may be formed to be discontinuous at every portion between the pixels in a vertical direction. That is, the data lines171R2may be formed like connected chains.

Referring toFIG. 10, a data line171R2is formed as a solid body, unlike the previous example embodiment in which the data line171R2is formed as a hollow ring shape. That is, the data line171R2present between the unit pixels PXU1and PXU2has a width larger than those of the data lines171G1,171B1,171G2, and171B2of the unit pixels PXU1and PXU2and is not hollow in a center region. The portions having a large width may be present across the plurality of pixels in a vertical direction, or may be formed between pixels in the vertical direction like a Vienna sausage. Because the data line171R2has a large width, distances to the pixel electrodes191B1and191R2adjacent thereto may be reduced, improving non-uniformity of capacitance with the data lines on both sides of the pixel electrodes191B1and191R2.

InFIGS. 11 and 12, the data line171R2between neighboring unit pixels PXU1and PXU2is formed to be the same as data lines171G1,171B1,171G2, and171B2between the pixel electrodes within the unit pixels PXU1and PXU2. That is, even the data line171R2, as well as the data lines171G1,171B1,171G2, and171B2, extend as linear lines overall. Here, a distance between the pixel electrode191B1and the data line171B1on the left side thereof and a distance between the pixel electrode191B1and the data line171R2on the right side thereof are different. A distance between the pixel electrode191R2and the data line171R2on the left side thereof and a distance between the pixel electrode191R2and the data line171G2on the right side thereof are also different.

In order to remove the effect of the difference in distances, a wing W1is electrically connected to the right side of the pixel electrode191B1. The wing W1may be formed to be parallel to the pixel electrode191B1at a predetermined distance, except for the portion thereof connected to the pixel electrode191B1, have a length substantially the same as that of the pixel electrode191B1, and formed to also be parallel to the data line171R2. A distance between the wing W1and the data line171R2and a distance between the pixel electrode191B1and the data line171B1may be substantially the same, whereby capacitance with the data lines171B1and171R2on both sides of the pixel electrode191B1may be substantially the same, thus preventing generation of spots.

Similarly, a wing W2is electrically connected to the right side of the pixel electrode191R2. The wing W2may be formed to be parallel to the pixel electrode191R2at a predetermined distance, except for the portion thereof connected to the pixel electrode191R2, have a length substantially the same as that of the pixel electrode191R2, and formed to also be parallel to the data line171R2. A distance between the wing W2and the data line171R2and a distance between the pixel electrode191G2and the data line171G2may be substantially the same, whereby capacitance with the data lines171R2and171G2on both sides of the pixel electrode191R2may be substantially the same. The wing W2may be formed to be symmetrical with the wing W1with respect to the data line171R2.

The wings W1and W2may be formed as only one in the pixel electrodes191B1and191R2as illustrated inFIG. 11, or a plurality of wings W1and W2may be connected to each of the pixel electrodes191B1and191R2as illustrated inFIG. 12.

The wings W1and W2may be formed together with the pixel electrodes191B1and191R2when the pixel electrodes191B1and191R2are formed. Because the wings W1and W2are electrically connected to the pixel electrodes191B1and191R2, a data voltage applied to the pixel electrodes191B1and191R2may also be applied to the wings W1and W2to generate light leakage or texture. Thus, the portions where the wings W1and W2are present may be covered by the light blocking member220positioned in the upper display substrate200or the lower display substrate100and the light blocking member220may be a light blocking member extending from the light blocking member220overlapping with the data line171R2.

FIGS. 13 and 14are views illustrating a change in a pixel electrode according to capacitance with data lines on both sides of a pixel electrode.

Referring toFIG. 13, a distance between the pixel electrode and a left data line is greater than a distance between the pixel electrode and a right data line. As a result, capacitance C1between the pixel electrode and the left data line is smaller than capacitance C2between the pixel electrode and the right data line. Here, when signals having the mutually opposite polarities are applied to the left data line and the right data line, coupling due to the capacitance C2is greater than coupling due to the capacitance C1. Thus, couplings on both sides of the pixel electrode are not uniform, and thus, a pixel voltage is changed due to a data signal applied to the both data lines.

Referring toFIG. 14, when a distance between the pixel electrode and the left data line and a distance between the pixel electrode and the right data line are equal, capacitance C1between the pixel electrode and the left data line and capacitance C2between the pixel electrode and the right data line may be the same. In this case, when signals having the mutually opposite polarities are applied to the left data line and the right data line, because coupling due to capacitance C1and coupling due to capacitance C1are the same, the two coupling effects are canceled out. As a result, because a pixel voltage is not changed, a degradation of image quality such as spots, or the like, due to coupling may not be generated.