Nano crystal display device having patterned microcavity structure

A display panel with microcavities each having ends of asymmetric cross-sectional area. An exemplary display panel has a substrate; a pixel electrode formed on the substrate; a first black matrix and a second black matrix each disposed on the substrate; and a supporting member disposed on the substrate over the pixel electrode and the black matrix, the supporting member shaped so as to form a microcavity between the pixel electrode and the supporting member, the microcavity having an upper surface proximate to the supporting member and a lower surface opposite the upper surface. The microcavity has one end positioned over the first black matrix, and another end opposite the first end and positioned over the second black matrix; the lower surface of the microcavity has first and second channels disposed therein, the first channel positioned over the first black matrix, and the second channel positioned over the second black matrix.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to, and the benefit of, Korean Patent Application No. 10-2013-0004996 filed in the Korean Intellectual Property Office on Jan. 16, 2013, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

Embodiments of the present invention relate generally to flat panel displays and their manufacture. More specifically, embodiments of the present invention relate to displays with patterned microcavity structures.

(b) Description of the Related Art

A liquid crystal display is one type of flat panel display devices that has found wide acceptance, and commonly includes two display panels where field generating electrodes such as pixel electrodes and a common electrode are formed, with a liquid crystal layer interposed therebetween. The liquid crystal display generates an electric field in the liquid crystal layer by applying voltages to the field generating electrodes, thus inducing specific orientations of liquid crystal molecules of the liquid crystal layer and thusly controlling the polarization of incident light, thereby displaying an image.

Liquid crystal displays can have a NCD (Nano Crystal Display) structure that employs a sacrificial layer formed of an organic material. A supporting member is coated thereon, then the sacrificial layer is removed, and a liquid crystal is filled in the empty space formed by removal of the sacrificial layer.

A method of manufacturing liquid crystal displays having a NCD structure also includes a process of injecting and drying an aligning agent before injecting the liquid crystal to arrange and align the liquid crystal molecules. In the process of drying the aligning agent, evaporation of the aligning agent may result in deposits of aligning agent solids such that light leakage or transmittance deterioration may be generated.

SUMMARY OF THE INVENTION

The present invention provides a liquid crystal display minimizing an agglomeration of a solid, and a manufacturing method thereof.

In one embodiment, a display panel comprises a substrate; a pixel electrode formed on the substrate; a first black matrix and a second black matrix each disposed on the substrate; and a supporting member disposed on the substrate over the pixel electrode and the black matrix. The supporting member is shaped so as to form a microcavity between the pixel electrode and the supporting member, the microcavity having an upper surface proximate to the supporting member and a lower surface opposite to the upper surface. The microcavity has a first end positioned over the first black matrix, and a second end opposite the first end and positioned over the second black matrix. Also, the lower surface of the microcavity has first and second channels disposed therein, the first channel positioned over the first black matrix, and the second channel positioned over the second black matrix.

The first channel can be positioned proximate to the first end, and the second channel can be positioned proximate to the second end.

The microcavity can extend lengthwise along a major axis, and have a minor axis oriented perpendicular to the major axis. The first black matrix and the second black matrix can each be oriented parallel to the major or the minor axis.

Widths of each of the first and second depressions can each be less than or equal to a height of the microcavity.

The pixel electrode can be a first pixel electrode, the microcavity can be a first microcavity, and the supporting member can be a first supporting member. The first microcavity can be disposed between the first pixel electrode and the first supporting member. The display panel can further comprise: a second pixel electrode disposed on the substrate proximate to the first pixel electrode; a second supporting member disposed on the substrate over the second pixel electrode; a second microcavity disposed between the second pixel electrode and the second supporting member, the second microcavity having a top surface proximate to the second supporting member and a bottom surface opposite to the top surface; and a third black matrix and a fourth black matrix each disposed on the substrate and under the second microcavity. The second microcavity can have a one end positioned over the third black matrix, and another end opposite the one end and positioned over the fourth black matrix. The bottom surface of the second microcavity can have third and fourth channels disposed therein, the third channel positioned over the third black matrix, and the fourth channel positioned over the fourth black matrix.

In another embodiment, a display panel can comprise a substrate; a pixel electrode disposed on the substrate; a black matrix disposed on the substrate; and a supporting member disposed on the substrate over the pixel electrode and the black matrix. The supporting member can be shaped so as to form a microcavity between the pixel electrode and the supporting member. The microcavity can have an upper surface proximate to the supporting member, a lower surface opposite to the upper surface, a first side surface extending between the upper and lower surfaces, and a second side surface opposite to the first side surface and extending between the upper and lower surfaces. At least one of the first and second side surfaces can have a plurality of depressions patterned therein.

The plurality of depressions can comprise a repeating pattern of depressions extending along a length of its respective side surface, each depression extending from the lower surface to the upper surface.

Each of the depressions can have an at least approximately triangular cross-sectional profile, an at least approximately U-shaped profile, an at least approximately trapezoidal cross-sectional profile, an at least approximately square cross-sectional profile, and/or an at least approximately sawtooth profile.

The depressions can each have a pitch of approximately 3 μm or less. Alternatively, the depressions can each have a pitch of approximately 1.8 μm.

Each of the depressions can be positioned over the black matrix.

The pixel electrode can be a first pixel electrode, the microcavity can be a first microcavity, the black matrix can be a first black matrix, and the supporting member can be a first supporting member. The first microcavity can be disposed between the first pixel electrode and the first supporting member. The display panel can further comprise: a second pixel electrode disposed on the substrate proximate to the first pixel electrode; a second supporting member disposed on the substrate over the second pixel electrode; a second microcavity disposed between the second pixel electrode and the second supporting member, the second microcavity having a top surface proximate to the second supporting member, a bottom surface opposite to the top surface, a third side surface extending between the top and bottom surfaces, and a fourth side surface opposite to the third side surface and extending between the top and bottom surfaces; and a second black matrix disposed on the substrate and under the second microcavity. The third and fourth side surfaces can each have a plurality of depressions patterned therein.

In a further embodiment, a method of manufacturing a display panel can comprise: forming a pixel electrode on a substrate; forming a black matrix on the substrate; and forming a supporting member on the substrate over the pixel electrode and the black matrix. The supporting member can be shaped so as to form a microcavity between the pixel electrode and the supporting member. The method can also include forming a feature proximate to at least one end of the microcavity, the feature positioned over the black matrix and configured to accumulate an aligning agent therein once the aligning agent is injected into the microcavity.

The forming a black matrix can further comprise forming a first black matrix and a second black matrix on the substrate. The microcavity can have an upper surface proximate to the supporting member and a lower surface opposite to the upper surface. The microcavity can have a first end positioned over the first black matrix, and a second end opposite the first end and positioned over the second black matrix. The forming a feature can further comprise forming at least one channel in the lower surface of the microcavity, the at least one channel positioned over at least one of the first black matrix and the second black matrix.

The forming at least one channel can further comprise forming first and second channels in the lower surface of the microcavity, the first channel positioned over the first black matrix, and the second channel positioned over the second black matrix.

The microcavity can have an upper surface proximate to the supporting member, a lower surface opposite to the upper surface, and at least one side surface extending between the upper and lower surfaces; and the method can further comprise patterning a plurality of depressions upon the at least one side surface.

The plurality of depressions can comprise a repeating pattern of depressions extending along a length of its respective side surface, each depression extending from the lower surface to the upper surface.

As described, according to an exemplary embodiment of the present invention, a trench is formed at an edge of a microcavity or a shape of the edge of the microcavity is patterned to have a non-linear shaped profile. Accordingly, a solid of an aligning agent is gathered at the trench or the non-linear shape, thereby minimizing light leakage or transmittance deterioration.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. However, the present invention is not limited to the exemplary embodiments described herein, and may be embodied in other forms. Rather, exemplary embodiments described herein are provided to thoroughly and completely explain the disclosed contents and to sufficiently transfer the ideas of the present invention to a person of ordinary skill in the art.

In the drawings, the thicknesses of layers and regions, as well as other dimensions, are exaggerated for clarity. It is to be noted that when a layer is referred to as being “on” another layer or substrate, it can be directly formed on the other layer or substrate or can be formed on the other layer or substrate with a third layer interposed therebetween. Like constituent elements are denoted by like reference numerals throughout the specification.

Embodiments of the invention relate to a display such as a liquid crystal display, where the display panel has a single substrate that holds both the pixel electrodes and common electrode, as well as a liquid crystal layer injected therebetween. The liquid crystal is held in a number of microcavities, each of which has openings for injection of the liquid crystal. The microcavities have trenches formed in their bottom surfaces, where the trenches are located over a black matrix. In this manner, solid residue from aligning agent injected into the microcavities accumulates in the trenches. As the trenches are positioned over a light-blocking layer, the accumulated solid residue is collected in an area that is not visible to the viewer, thus preventing any deleterious visual effects. Alternative configurations include patterns etched into side walls of the microcavities and positioned over a black matrix, rather than (or in addition to) trenches, where these side wall patterns also act to collect aligning agent solids thereon.

FIG. 1is a top plan view of a liquid crystal display according to an exemplary embodiment of the present invention.FIG. 2is a top plan view schematically explaining an arrangement of a trench according to an exemplary embodiment of the present invention ofFIG. 1.FIG. 3is a cross-sectional view taken along a line ofFIG. 1.FIG. 4is a cross-sectional view taken along a line IV-IV ofFIG. 1.FIG. 5is a perspective view of a microcavity according to an exemplary embodiment of the present invention.

Referring toFIG. 1,FIG. 3, andFIG. 4, thin film transistors Qa, Qb, and Qc are formed on a substrate110made of transparent glass or plastic.

An organic layer230is positioned on the thin film transistors Qa, Qb, and Qc, and a light blocking member220may be formed between neighboring organic layers230. Here, the organic layer230may be a color filter.

FIG. 3andFIG. 4are cross-sectional views taken along the lines III-III and IV-IV, and certain elements shown inFIG. 1as being between the substrate110and the organic layer230are omitted inFIG. 3andFIG. 4for clarity. In actuality,FIG. 3andFIG. 4include at least portions of the thin film transistors Qa, Qb, and Qc between the substrate110and the organic layer230.

The organic layer230may extend generally along a column direction of the pixel electrode191. The organic layer230may be a color filter, and each of the color filters230may display one of a primary color such as red, green, or blue. However, embodiments of the invention are not limited to these primary colors, and may also display any of cyan, magenta, yellow, and white-based colors, or any other color for display of an image.

As shown inFIG. 1, the neighboring organic layers230may be spaced apart from each other in a horizontal direction D and in a vertical direction crossing (and, here, generally perpendicular to) the horizontal direction D.FIG. 3shows exemplary organic layers230that are separated from or spaced apart from each other in the horizontal direction D, andFIG. 4shows organic layers230that are separated from each other in the vertical direction.

Referring toFIG. 3, longitudinal light blocking members220bor black matrices are positioned between the organic layers230separated along the horizontal direction D. The longitudinal light blocking members220brespectively overlap each edge of the neighboring organic layers230, and a width by which the longitudinal light blocking members220boverlap both edges of the organic layer230is substantially the same. That is, each side of the longitudinal light blocking members220boverlaps its adjacent organic layer230to the same degree.

Referring toFIG. 4, a transverse light blocking member220ais formed between neighboring organic layers230that are separated in the vertical direction. Transverse light blocking members220arespectively overlap the neighboring organic layers230, and the widths at which each transverse light blocking member220aoverlaps both edges of its adjacent organic layers230are substantially the same.

The lower passivation layer170and the upper passivation layer180are positioned on the organic layer230and the light blocking member220. The lower passivation layer170may be formed of an organic material and may have a planarizing function, effectively flattening the uneven upper surfaces of their underlying layers. The upper passivation layer180may be formed of an inorganic material such as silicon oxide or silicon nitride. The upper passivation layer180may be omitted.

A pixel electrode191is positioned on the upper passivation layer180, and the pixel electrode191is electrically connected to one terminal of the thin film transistors Qa and Qb through contact holes185aand185b.

A lower alignment layer11is formed on the pixel electrode191, and the lower alignment layer11may be a vertical alignment layer. The lower alignment layer11can be a liquid crystal alignment layer made of one or more materials such as polyamic acid, polysiloxane, or polyimide.

A microcavity400is formed on the lower alignment layer11. The microcavity400is a cavity that can hold a liquid. Here, the microcavity400is injected with a liquid crystal material including liquid crystal molecules310, and the microcavity400has a liquid crystal injection hole A through which the liquid crystal material is injected. The microcavity400may be formed with a major axis extending along a column direction of the pixel electrodes191, in other words, in a longitudinal direction. The minor axis of microcavity400extends laterally, or parallel to direction D ofFIG. 1. In the present exemplary embodiment, the alignment material forming alignments layers11and21, as well as a liquid crystal material including the liquid crystal molecules310, may each be injected into the microcavity400by using a capillary force.

In the present exemplary embodiment, as shown inFIG. 2andFIG. 3, an open part OPN is formed between the microcavity400neighboring in the horizontal direction and a trench SP is formed at both edges of the microcavity400adjacent to the microcavity400and the trenches SP may be formed over portions of the organic layer230and the transverse light blocking member220bthat overlap each other. More generally, the trenches SP may be formed over the light blocking member220b. At this time, it is preferable that the first width w1 of the trench SP formed at the edge of the microcavity400is less than the cell gap of the liquid crystal layer including liquid crystal molecules310, i.e. less than the height of the interior of the microcavity400. As shown inFIG. 2, a space between neighboring short edges of the pixel electrodes191aand191bincludes a region where a liquid crystal injection hole A of the microcavity400is formed, and may be referred to as an inlet part EP. The inlet part EP may have substantially the same width as the transverse light blocking member220a.

The trench SP extends along the vertical direction or major axis of the microcavity400, and the first length L1 corresponding to the length (as measured along the major axis) of the trench SP may extend to within the inlet part EP.

InFIG. 2, when viewed along the vertical direction, the trenches SP are not continuous, but instead are separated by gaps at the inlet part EP. However, this need not be the case, and embodiments of the invention contemplate continuous trenches SP that have no such gaps.

The cell gap of the liquid crystal layer may be in a range of more than about 2 um to less than about 10 urn.

In a manufacturing process of a liquid crystal display, not only the liquid crystal material may be injected through the liquid crystal injection hole A, but also an alignment material of which a solid and a solvent are mixed. That is, the manufacturing process involves first injecting the alignment material, drying the alignment material, and then injecting liquid crystal. More specifically, a drying process is performed after injection of the alignment material. At this time, the solid remaining when the solvent is volatilized may be agglomerated inside the microcavity400. That is, when the alignment material is dried, its liquids vaporize but its solids are left behind. These solids form deposits within the microcavity400. In conventional microcavity configurations, when the drying simultaneously starts at the two injection holes of both sides and the drying progresses toward the center portion of the microcavity400, solids accumulate at the center of the microcavity400, thereby generating a huddle defect, i.e. a dark spot formed by accumulation of dried solids from the aligning agent. Also, if the drying starts at one side of the liquid crystal injection hole, the solid may be agglomerated at the liquid crystal injection hole at the other side of the microcavity. In this way, if the solid is agglomerated inside the microcavity, a display defect such as light leakage or transmittance deterioration is generated.

In the present exemplary embodiment, if the trench SP is formed at the edge of the microcavity400, agglomeration of aligning agent solids is decreased at the liquid crystal injection hole A, so that light leakage and other deleterious effects are minimized. If the width w1 of the trench SP is less than the cell gap of the liquid crystal layer, the capillary force of the trench SP structure is higher than the capillary force of the microcavity400, so that the remaining solid may be induced to the trench SP. Like this, the remaining solid after the drying is spread to the trench SP thereby preventing agglomeration of the solid in a visible area.

In the present exemplary embodiment, one liquid crystal injection hole is disposed at both edges of the microcavity400, as another exemplary embodiment, one liquid crystal injection hole may be only disposed at one edge of the microcavity400.

The upper alignment layer21is positioned on the microcavity400, and a common electrode270and an first overcoat250are formed on the upper alignment layer21. The common electrode270receives a common voltage and the pixel electrode191receives a data voltage, so as to collectively generate an electric field within the liquid crystal. This electric field determines an inclination direction of the liquid crystal molecules310positioned in the minute space layer400between the two electrodes. The common electrode270and the pixel electrode191together form a capacitor (hereafter referred to as “a liquid crystal capacitor”) to maintain the applied voltage after the thin film transistor is turned off. The first overcoat250may be formed of silicon nitride (SiNx) or silicon oxide (SiO2).

A supporting member260is positioned on the first overcoat250. The supporting member260may include silicon oxycarbide (SiOC), a photoresist, or an organic material. When the supporting member260includes silicon oxycarbide (SiOC), a chemical vapor deposition method may be used, and when including the photoresist, a coating method may be applied. Among layers that may be formed through chemical vapor deposition, silicon oxycarbide (SiOC) layers have high transmittance and low layer stress. Accordingly, in the present exemplary embodiment, the supporting member260can be formed of silicon oxycarbide (SiOC) such that light is transmitted well and the layer is stable.

A groove GRV passing under the microcavity400, the upper alignment layer21, the common electrode270, the first overcoat250, and the supporting member260is formed over the transverse light blocking member220a.

Referring toFIG. 1andFIG. 3toFIG. 5, the microcavity400is divided into individual cavities by a plurality of grooves GRV overlapping gate lines121a, and a plurality of microcavity400are thereby formed along a direction D in which the gate line121agenerally extends. The plurality of microcavity400may respectively correspond to a pixel area, and multiple groups of the pluralities of microcavity400may be formed along the column direction. Here, pixel area may correspond to a region displaying the image.

The present exemplary embodiment has a thin film transistor and pixel electrode design structure in which two sub-pixel electrodes191aand191bare disposed via the gate line121interposed therebetween. Accordingly, one microcavity400corresponds to the first subpixel electrode191aand the second subpixel electrode191bof one pixel PX. However, any other thin film transistor or pixel design structure is contemplated, and the microcavity400may be formed over any such pixel.

At this time, the groove GRV formed between the microcavity400may extend along the direction D that the gate line121aextends, and the liquid crystal injection holes A1 and A2 of the microcavity400form a region corresponding to a boundary of the groove GRV and the microcavity400. The liquid crystal injection hole A is formed along a direction that the groove GRV extends. Also, an opening part OPN formed between neighboring microcavity400in the direction D that the gate line121aextends may be covered by the supporting member260as shown inFIG. 3.

The liquid crystal injection hole A included in the microcavity400may be widely positioned between the supporting member260and the pixel electrode191, but may be positioned between the upper alignment layer21and the lower alignment layer11.

In the present exemplary embodiment, the groove GRV is formed to extend along the direction D that the gate line121aextends. However, as another exemplary embodiment, a plurality of grooves GRV may be formed to extend along a direction that a data line171extends, so that multiple groups of the plurality microcavity400may be formed in a row direction. The liquid crystal injection hole A may be formed parallel to the direction along which the groove GRV extends.

A second overcoat240is positioned on the supporting member260. The second overcoat240may be formed of silicon nitride (SiNx) or silicon oxide (SiO2). A capping layer280is positioned on the second overcoat240. The capping layer280contacts the upper surface of the second overcoat240and the side surface of the supporting member260, and the capping layer280covers the liquid crystal injection holes A of the microcavity400exposed by the groove GRV. The capping layer280may be made of a thermal hardening resin, silicon oxycarbide (SiOC), or graphene.

When the capping layer280is formed of graphene, the graphene has transmission resistance against a gas including helium, thereby acting as a capping layer for capping the liquid crystal injection hole A. The capping layer280may be made of a carbon combination such that the liquid crystal material is not contaminated even if it contacts the capping layer280. Also, the graphene protects the liquid crystal material from oxygen or moisture from the outside.

In the present exemplary embodiment, the liquid crystal material is injected through the liquid crystal injection hole A of the minute space layer400, thereby forming a liquid crystal display without the additional formation of an upper substrate. That is, the microcavities400hold a liquid crystal layer on the same substrate110as the pixel electrode191and common electrode270, thus preventing the need for a second substrate. This has significant advantages, including allowing for a thinner display than conventional displays that use two substrates, as well as making for cheaper and more easily manufacturable displays.

An overcoat (not shown) made of an organic layer or an inorganic layer may be positioned on the capping layer280. The overcoat protects the liquid crystal molecules310injected into the microcavity400from an external impact that may flatten them.

Next, again referring toFIG. 1toFIG. 4, a liquid crystal display according to the present exemplary embodiment will be described.

Referring toFIG. 1toFIG. 4, a plurality of gate conductors including a plurality of gate lines121a, a plurality of step-down gate lines121b, and a plurality of storage electrode lines131are formed on a substrate110made of transparent glass or plastic.

The gate lines121aand the step-down gate lines121bextend mainly in a transverse direction, and transmit gate signals. The gate line121aincludes a first gate electrode124aand a second gate electrode124bprotruding upward and downward respectively in the view ofFIG. 1, and the step-down gate line121bincludes a third gate electrode124cprotruding upward in the view ofFIG. 1. The first gate electrode124aand the second gate electrode124bare connected to each other to form a single protrusion.

The storage electrode lines131are mainly extended in the transverse direction (i.e. along direction D inFIG. 1), and transfer a predetermined voltage such as a common voltage. Each storage electrode line131includes a storage electrode129protruding upward and downward from the storage electrode line131in the view ofFIG. 1, a pair of longitudinal portions134extending substantially perpendicular to the gate lines121aand121band downward, and a transverse portion127connecting ends of the pair of longitudinal portions134. The transverse portion127includes a capacitive electrode137extending downward.

A gate insulating layer140is formed on the gate conductors121a,121b, and131.

A plurality of semiconductor stripes (partially shown) that may be made of amorphous silicon or crystallized silicon are formed on the gate insulating layer140. The semiconductor stripes mainly extend in the longitudinal direction, and include first and second semiconductors154aand154bprotruding toward the first and second gate electrodes124aand124band connected to each other, and a third semiconductor154cdisposed on the third gate electrode124c.

A plurality of pairs of ohmic contacts (not shown) are formed on the semiconductors154a,154b, and154c. The ohmic contacts may be made of silicide or of n+ hydrogenated amorphous silicon doped with an n-type impurity at a high concentration.

A data conductor including a plurality of data lines171, a plurality of first drain electrodes175a, a plurality of second drain electrodes175b, and a plurality of third drain electrodes175cis formed on the ohmic contacts.

The data lines171transmit data signals and extend in a longitudinal direction, thereby intersecting, though insulated from, the gate line121aand the step-down gate line121b. Each data line171includes a first source electrode173aand a second source electrode173bextending toward the first gate electrode124aand the second gate electrode124brespectively, and connected to each other.

The first drain electrode175a, the second drain electrode175b, and a third drain electrode175ceach include one end having a wide area and the other end having a bar type shape. Bar ends of the first drain electrode175aand the second drain electrode175bare partially enclosed by the first source electrode173aand the second source electrode173b. The wide end of the first drain electrode175aalso has a portion extending to semiconductor154c, thereby forming a third source electrode173cwhich is curved to have a “U” shape. A wide end177cof the third drain electrode175coverlaps the capacitive electrode137thereby forming a step-down capacitor Cstd, and the bar end is partially enclosed by the third source electrode173c.

The first gate electrode124a, the first source electrode173a, and the first drain electrode175aform a first thin film transistor Qa along with the first semiconductor154a; the second gate electrode124b, the second source electrode173b, and the second drain electrode175bform a second thin film transistor Qb along with the second semiconductor154b; and the third gate electrode124c, the third source electrode173c, and the third drain electrode175cform a third thin film transistor Qc along with the third semiconductor154c.

The semiconductor stripes including the first semiconductor154a, the second semiconductor154b, and the third semiconductor154cexcept for the channel region between the source electrodes173a,173b, and173c, and the drain electrodes175a,175b, and175chave substantially the same plane shape as the data conductors171a,171b,173a,173b,173c,175a,175b, and175cand the underlying ohmic contacts (i.e., the same shape in the plan view ofFIG. 1).

The first semiconductor154aincludes a portion that is not covered by the first source electrode173aand the first drain electrode175ato be exposed between the first source electrode173aand the first drain electrode175a, the second semiconductor154bincludes a portion that is not covered by the second source electrode173band the second drain electrode175bto be exposed between the second source electrode173band the second drain electrode175b, and the third semiconductor154cincludes a portion that is not covered by the third source electrode173cand the third drain electrode175cto be exposed between the third source electrode173cand the third drain electrode175c.

A lower passivation layer (not shown) made of an inorganic insulator such as silicon nitride or silicon oxide is formed on the data conductors171a,171h,173a,173b,173c,175a,175b, and175cand the exposed first, second, and third semiconductors154a,154b, and154c.

The organic layer230may be positioned on the lower passivation layer. The organic layer230is present across most of the display area except for positions where the first thin film transistor Qa, the second thin film transistor Qb, and the third thin film transistor Qc are disposed. However, it may extend in the longitudinal direction along the space between adjacent data lines171. In the present exemplary embodiment, the organic layer230may be a color filter, and the color filter230may be formed under the pixel electrode191. However, it may alternatively be formed on the common electrode270.

The light blocking member220is positioned on a region where the organic layer230is not present, and on a portion of the organic layer230. That is, light blocking members220are positioned between, and slightly overlapping, neighboring organic layers230. The light blocking member220includes transverse light blocking member220aextending along the gate line121aand the step-down line121b, and covering the region at which the first thin film transistor Qa, the second thin film transistor Qb, and the third thin film transistor Qc are disposed, as well as longitudinal light blocking member220bthat extends along the data line171.

The light blocking member220is referred to as a black matrix, and prevents light leakage.

The lower passivation layer and the light blocking member220have a plurality of contact holes185aand185bexposing the first drain electrode175aand the second drain electrode175b, respectively.

Also, the lower passivation layer170and the upper passivation layer180are formed on the organic layer230and the light blocking member220and a pixel electrode191including a first sub-pixel electrode191aand a second sub-pixel electrode191bis formed on the upper passivation layer180. The first sub-pixel electrode191aand the second sub-pixel electrode191bare positioned on opposite sides of the gate line121aand the step-down gate line121b, and are disposed upward and downward such that they are adjacent to each other in the column direction. The height of the second sub-pixel electrode191bis greater than the height of the first sub-pixel electrode191a, and may be in a range of about 1 to 3 times that of the first sub-pixel electrode191a.

Each overall shape of the first sub-pixel electrode191aand the second sub-pixel electrode191bis a quadrangle, and the first sub-pixel electrode191aand the second sub-pixel electrode191brespectively include a cross stem including transverse stems193aand193band longitudinal stems192aand192bcrossing the transverse stems193aand193b. Also, the first sub-pixel electrode191aand the second sub-pixel electrode191brespectively include a plurality of minute branches194aand194b, and protrusions197aand197bprotruding upward or downward from the edge of the sub-pixel electrodes191aand191h.

The pixel electrode191is divided into four sub-regions by the transverse stems193aand193band the longitudinal stems192aand192b. The minute branches194aand194bobliquely extend from the transverse stems193aand193band the longitudinal stems192aand192b, and the extending direction thereof forms an angle of about 45 degrees or 135 degrees with the gate lines121aand121bor the transverse stems193aand193b. Also, the minute branches194aand194bof two neighboring sub-regions may be crossed.

In the present exemplary embodiment, the first sub-pixel electrode191afurther includes an outer stem enclosing the outer portion, and the second sub-pixel electrode191bfurther includes a transverse portion disposed on the upper and lower portions and right and left longitudinal portions198disposed on the right and left sides of the second sub-pixel electrode191b. The right and left longitudinal portions198may prevent capacitive coupling between the data line171and the first sub-pixel electrode191a.

The lower alignment layer11, the microcavity400, the upper alignment layer21, the common electrode270, the first overcoat250, and the capping layer280are formed on the pixel electrode191, and the description of these constituent elements is not repeated here.

The above described liquid crystal display is but one embodiment representing one application of the invention. One of ordinary skill in the art will realize that other applications exist. For example, one of ordinary skill in the art will realize that embodiments of the invention can be implemented in other displays besides a liquid crystal display.

A manufacturing method for a liquid crystal display according to another exemplary embodiment of the present invention will be described with reference toFIG. 6toFIG. 12.FIG. 6toFIG. 12are cross-sectional views of a method of manufacturing a liquid crystal display according to another exemplary embodiment of the present invention, and these figures sequentially show stages in the fabrication of a liquid crystal display as viewed from the cross-section taken along the line III-III ofFIG. 1.

Referring toFIG. 6, thin film transistors Qa, Qb, and Qc (shown inFIG. 1) are formed on a substrate110made of transparent glass or plastic. An organic layer230corresponding to a pixel area is formed on the thin film transistors Qa, Qb, and Qc, and a light blocking member220, including transverse light blocking member220aand longitudinal light blocking member220b, is formed between the neighboring organic layers230. As shown inFIG. 6, the longitudinal light blocking member220boverlaps the edges of its neighboring organic layers230. As the overlapping of the longitudinal light blocking member220band the organic layer230is increased, a resulting step, or bumplike protrusion, may be generated in the upper surface of member220bby a leveling effect. The height of the step may be controlled by controlling the interval overlapping the organic layer230(i.e., the amount of overlap between the member220band layer230) when forming the longitudinal light blocking member220b. In this manner, each step or protrusion may be independently fabricated to a range of heights, or may be made to not exist at all.

Here, the organic layer230may be a color filter.

Referring toFIG. 7, the lower passivation layer170is formed on the organic layer230and the light blocking member220. The lower passivation layer170may be formed of an organic material. The lower passivation layer170is patterned to be elongated in, i.e. to extend along, the vertical direction, and the trench SP having the first width w1 is formed. As shown inFIG. 2, the trench SP is positioned between pixels that are adjacent in the horizontal direction, and the trench SP may be positioned over that portion of the longitudinal light blocking member220bthat overlaps the organic layer230.

Referring toFIG. 8, the upper passivation layer180is formed on the lower passivation layer170. The upper passivation layer180may be formed of an inorganic material such as silicon oxide or silicon nitride, and may be omitted if so desired. Next, after forming a pixel electrode material on the upper passivation layer180, the pixel electrode material is patterned to form the pixel electrode191in the pixel area, and at this time, the pixel electrode191is electrically connected to one terminal of the thin film transistors Qa and Qb through the contact holes185aand185b(shown inFIG. 1). The pixel electrode191formed by patterning the pixel electrode material may have the shape shown inFIG. 2, however it is not limited thereto and the design of the pixel electrode191may take on any suitable shape.

Referring toFIG. 9, a sacrificial layer300including silicon oxycarbide (SiOC) or a photoresist is formed on the pixel electrode191. The sacrificial layer300may be formed of an organic material as well as silicon oxycarbide (SiOC) or a photoresist.

The sacrificial layer300is patterned to form an open part OPN on the longitudinal light blocking member200b. The open part OPN may divide the microcavity400in the horizontal direction.

The common electrode270and the first overcoat250are sequentially formed on the sacrificial layer300. The common electrode270may be made of a transparent conductor such as ITO or IZO, and the first overcoat250may be made of silicon nitride (SiNx) or silicon oxide (SiO2). The common electrode260and the first overcoat250may cover the open part OPN between the microcavity400.

Referring toFIG. 10, a supporting member260and a second overcoat240are sequentially formed on the overcoat250. The supporting member260according to the present exemplary embodiment may be made of a different material from the sacrificial layer300. The second overcoat240may be made of silicon nitride (SiNx) or silicon oxide (SiO2).

FIG. 11is a cross-sectional view taken along the line IV-IV ofFIG. 1during the fabrication step ofFIG. 10. Referring toFIG. 11, before forming the second overcoat240, the supporting member260is patterned to form a groove GRV exposing the first overcoat250at a position corresponding to the transverse light blocking member220a. The portions of the second overcoat240, the first overcoat250, and the common electrode270over the groove GRV are sequentially patterned to expose the sacrificial layer300, and the sacrificial layer300is then removed through the groove GRV by an O2ashing process or a wet etching method. A microcavity400having the liquid crystal injection hole A is thereby formed. The microcavity400is an empty space where the sacrificial layer300has been removed. The liquid crystal injection hole A may be formed along a direction parallel to the signal line connected to one terminal of the thin film transistor. If the sacrificial layer300is removed, as shown inFIG. 10, the common electrode270, the overcoat250, and the supporting member260cover the open part OPN such that an edge side wall of the microcavity400is formed as a partition.

Referring toFIG. 12, an alignment material is injected through the liquid crystal injection hole A shown inFIG. 11to form alignment layers11and21on the pixel electrode191and the common electrode270. The alignment material has both solids and a solvent. A baking process is performed after injecting the alignment material through the liquid crystal injection holes A. At this time, the alignment layer is formed while the solvent of the alignment material is volatilized and the remaining solids are induced to accumulate within the trench SP while drying progresses to the side of the liquid crystal injection hole A. The solid induced to accumulate within the trench SP may be dragged to the inlet part EP shown inFIG. 2, or may remain in the trench SP. Either way, since both the trench SP and inlet part EP are positioned over the light blocking member220, deleterious effects from accumulation of aligning agent solids, such as light leakage, may be prevented. The width w1 of the trench SP is less than the cell gap and the capillary force preferentially acts at this portion, such that solids may be induced to accumulate in the trench SP.

Next, a liquid crystal material including liquid crystal molecules310is injected into the microcavity400through the groove GRV and the liquid crystal injection holes A using an inkjet method.

Next, the capping layer280covering the upper surface and the side surface of the supporting member260is formed, and at this time, the capping layer280covers the liquid crystal injection holes A of the microcavity400exposed by the groove GRV, thereby completing the liquid crystal display shown inFIG. 3andFIG. 4.

FIG. 13is a top plan view of a liquid crystal display according to an exemplary embodiment of the present invention.FIG. 14is a cross-sectional view taken along the line XIV-XIV ofFIG. 13.

Referring toFIG. 13andFIG. 14, many elements are the same as the exemplary embodiment described with reference toFIG. 1,FIG. 3, andFIG. 4. However, as shown inFIG. 13, the trenches SP extending in the vertical direction at both edges of the microcavity400are also extended in the horizontal direction, thereby forming an additional storage trench SP1. The storage trench SP1 is formed within the inlet part EP, so that some solids are dragged into the inlet part EP from the trench SP in the microcavity400, to be gathered at the storage trench SP1. The width w2 of the storage trench SP1 may be controlled to be within the interval of the inlet part EP. That is, the storage trench SP1 lies within, and is no wider than, inlet part EP.

In the present exemplary embodiment, the inlet part EP lies over the light blocking member220, and when the remaining solid is gathered at the storage trench SP1, the alignment layer that is vertically aligned may be formed at the inlet part EP. The alignment layer that is vertically aligned makes a black state such that there is a merit of reducing the material cost of the light blocking member formed at the inlet part EP.

Most of the description inFIGS. 1, 3, and 4may be applied to the exemplary embodiment described inFIG. 13andFIG. 14, except for the storage trench SP1 added to the described exemplary embodiment. Accordingly, redundant explanations have been omitted.

Next, a method of manufacturing a liquid crystal display according to another exemplary embodiment of the present invention will be described with reference toFIG. 15toFIG. 21.FIG. 15toFIG. 21are cross-sectional views sequentially showing stages in the fabrication of a liquid crystal display as viewed from the cross-section taken along the line XIV-XIV ofFIG. 13.

Referring toFIG. 15, thin film transistors Qa, Qb, and Qc (shown inFIG. 1) are formed on a substrate110made of transparent glass or plastic. Organic layers230corresponding to a pixel area are formed on the thin film transistors Qa, Qb, and Qc, and blocking members220including transverse light blocking members220aand longitudinal light blocking members220bare formed between neighboring organic layers230. As shown inFIG. 15, each transverse light blocking member220aoverlaps the edges of its neighboring organic layers230. As the overlapping of the transverse light blocking member220aand the organic layer230is increased, the step or vertical protrusion produced by the leveling effect may be generated. When forming the transverse light blocking members220a, the heights of the step protrusions may be controlled by controlling the amount of overlap with the organic layer230, or alternatively a step may not be generated.

Here, the organic layer230may be a color filter.

The lower passivation layer170is formed on the organic layer230and the light blocking member220. The lower passivation layer170may be formed of an organic material. The first passivation layer170is patterned to form a storage trench SP1 extending in the horizontal direction and having a second width L2. As shown inFIG. 13, the storage trench SP1 is formed within the inlet part EP such that it overlaps the transverse light blocking member220a. The storage trench SP1 may be simultaneously formed along with the trench SP extending in the vertical direction and having the first width w1.

Referring toFIG. 16, the upper passivation layer180is formed on the lower passivation layer170. The upper passivation layer180may be formed of an inorganic material such as silicon oxide or silicon nitride, and may be omitted if desired. Next, after forming a pixel electrode material on the upper passivation layer180, the pixel electrode material is patterned to form the pixel electrode191to be positioned at the pixel area, and at this time, the pixel electrode191is electrically connected to one terminal of the thin film transistors Qa and Qb through the contact holes185aand185b(shown inFIG. 1). The pixel electrode191formed by patterning the pixel electrode material may have the shape shown inFIG. 13, however it is not limited thereto and the design of the pixel electrode191may take on any other suitable shape.

A sacrificial layer300including silicon oxycarbide (SiOC) or a photoresist is formed on the pixel electrode191. The sacrificial layer300may be formed of an organic material as well as silicon oxycarbide (SiOC) or photoresist.

Referring toFIG. 17, a common electrode270, an overcoat250, and a supporting member260are sequentially formed on the sacrificial layer300. The common electrode270may be made of a transparent conductor such as ITO or IZO, and the first overcoat250may be made of silicon nitride (SiNx) or silicon oxide (SiO2). The supporting member260according to the present exemplary embodiment may be made of a different material from the sacrificial layer300.

The supporting member260is patterned to form a groove GRV exposing the first overcoat250at positions over the transverse light blocking member220a.

Referring toFIG. 18, a second overcoat240covering the exposed first overcoat250and supporting member260is formed. The second overcoat240may be formed of silicon nitride (SiNx) or silicon oxide (SiO2).

Referring toFIG. 19, the second overcoat240, the first overcoat250and the common electrode270corresponding to the groove GRV are sequentially patterned to expose the sacrificial layer300. At this time, a portion of the sacrificial layer300under the groove GRV may be removed.

Referring toFIG. 20, the sacrificial layer300is removed through the groove GRV by an O2ashing process or a wet etching method. A microcavity400having liquid crystal injection hole A is thereby formed. The microcavity400is an empty space where the sacrificial layer300is removed, and forms a cavity capable of holding a liquid such as liquid crystal. The liquid crystal injection hole A may be formed along the direction parallel to the signal line connected to one terminal of the thin film transistor.

Referring toFIG. 21, an alignment material is injected through the liquid crystal injection hole A shown inFIG. 20to form alignment layers11and21on the pixel electrode191and the common electrode270. A baking process is performed after injecting the alignment material through the liquid crystal injection holes A. At this time, alignment layer solids are accumulated in the trench SP shown inFIG. 12while the drying progresses to the side of the liquid crystal injection hole A. At least part of the solid induced to collect within the trench SP is dragged to the inlet part EP shown inFIG. 13and is gathered in the storage trench SP1. The width w2 of the storage trench SP1 may be formed to be as wide as or narrower than the inlet part EP, and to lie within its boundaries.

FIG. 22is a top plan view schematically explaining an arrangement of a trench according to an exemplary embodiment of the present invention.FIG. 23is a cross-sectional view taken along the line XXIII-XXIII ofFIG. 22.

The exemplary embodiment shown inFIG. 22andFIG. 23has largely the same configuration as the exemplary embodiment ofFIG. 1toFIG. 5, however the trench SP shown inFIG. 2andFIG. 3is not formed. Instead of the trench SP, a non-linear part NSLP having a similar function to the trench SP is formed at the edge of the microcavity400. Besides the non-linear part NSLP, other elements of the embodiment ofFIG. 1toFIG. 5may be applied to the present exemplary embodiment, and repetitive explanation of these other elements is omitted for clarity.

Referring toFIG. 22, a plurality of microcavity400are formed in a matrix shape (when viewed in plan view), with microcavity400that neighbor in the vertical direction being separated by a groove GRV interposed therebetween. Referring toFIG. 23, microcavity400adjacent in the horizontal direction are divided by the open part OPN, and the common electrode270, the overcoat250, and the supporting member260covering the open part OPN thereby forming a side wall400wof the microcavity400.

These edge side walls are walls connecting the upper and lower surfaces of the cavity400, and are shown as the angled sides shown in the center portion ofFIG. 23. The non-linear parts NSLP are patterns etched into the surface of the edge side walls.

FIG. 23shows the location of the non-linear part NSLP in the microcavity400. As shown inFIG. 22the non-linear part NSLP can be a zigzag pattern etched into the edge side walls, so that the side walls have the zigzag profile shown. A pitch d of the repetition shape of the non-linear part NSLP is less than the cell gap of the liquid crystal layer.

Like the present exemplary embodiment, if the non-linear part NSLP is formed in the edges of the microcavity400, the agglomeration of the solid of the aligning agent is decreased at the liquid crystal injection hole A after injecting and drying the aligning agent, so that light leakage and other deleterious effects are minimized. If the pitch d of the non-linear part NSLP is less than the cell gap of the liquid crystal layer, the capillary force of the non-linear part NSLP structure is higher than the capillary force of the microcavity400such that the remaining solid may be induced to the non-linear part NSLP. Like this, the remaining solid is spread to the non-linear part NSLP thereby preventing the agglomeration of the solid in a visible area.

The non-linear part NSLP of the microcavity400is positioned at a portion overlapping the light blocking member220, such that aligning agent solids accumulate over a part of the display that is unseen by the viewer. Also, the solid may appropriately filled the protrusions and depressions of the non-linear part NSLP to such a degree that the edge side wall of the microcavity400may be made substantially flat.

Referring toFIG. 24, the non-linear part NSLP of the microcavity400according to the present exemplary embodiment is not limited to the zigzag shape ofFIG. 22, and may instead be formed to have a circular, trapezoidal, rectangular, or triangular zigzag profile, as shown. Any other profile is also contemplated, so long as it results in accumulation of aligning agent solids therein.

FIG. 25toFIG. 31are cross-sectional views and top plane views of a manufacturing method of a liquid crystal display according to another exemplary embodiment of the present invention.

Referring toFIG. 25andFIG. 26, thin film transistors Qa, Qb, and Qc (shown inFIG. 1) are formed on a substrate110made of transparent glass or plastic. An organic layer230corresponding to a pixel area is formed on the thin film transistors Qa, Qb, and Qc, and a light blocking member220, including a transverse light blocking member220aand a longitudinal light blocking member220b, is formed between the neighboring portions of the organic layer230. As shown inFIG. 26, the longitudinal light blocking member220boverlaps edges of the neighboring organic layer230.

After forming a pixel electrode material on the organic layer230, the pixel electrode material is patterned to form a pixel electrode191positioned at the pixel area.

Referring toFIG. 27andFIG. 28, a sacrificial layer300including silicon oxycarbide (SiOC) or a photoresist is formed on the pixel electrode191. The sacrificial layer300may be formed of an organic material as well as silicon oxycarbide (SiOC) or photoresist.

The sacrificial layer300is patterned to form an open part OPN on the longitudinal light blocking member200b. The open part OPN may divide the portions of the microcavity400that neighbor each other in the horizontal direction. At this time, as shown inFIG. 27, a non-linear part NSLP including a protrusion and depression part PTP is formed in the exposed edge of the sacrificial layer300. As described above, it is preferable for a pitch of the protrusion and depression part PTP to be less than the cell gap of the liquid crystal layer.

Referring toFIG. 29, the common electrode270and the first overcoat250are sequentially formed on the sacrificial layer300. The common electrode270may be made of a transparent conductor such as ITO or IZO, and the first overcoat250may be made of silicon nitride (SiNx) or silicon oxide (SiO2). The common electrode260and the first overcoat250may cover the open part OPN between the microcavity400.

Referring toFIG. 30andFIG. 31, a supporting member260having a groove GRV is formed on the overcoat250, and then a second overcoat240is formed on the supporting member260. The following process is performed similarly to the previously described exemplary embodiment. In this manner, the passivation layer240, the overcoat250, and the common electrode270positioned at the portion corresponding to the groove GRV are sequentially patterned to expose the sacrificial layer300, and the sacrificial layer300is removed by an ashing process or wet etching method. If the sacrificial layer300is removed, the microcavity400having the liquid crystal injection hole A is formed at this position.

If the sacrificial layer300is removed, as shown inFIG. 31, the common electrode270, the overcoat250, and the supporting member260cover the open part OPN such that an edge side wall of the microcavity400is formed as a partition. The portion corresponding to the edge side wall of the microcavity400has the same shape as the non-linear part NSLP of the sacrificial layer300, such that the non-linear part NSLP including the protrusion and depression part PTP is formed in the edge of the microcavity400.

Referring toFIG. 31, an alignment material is injected through the liquid crystal injection hole A shown inFIG. 30to form alignment layers11and21on the pixel electrode191and the common electrode270. A baking process is performed after injecting the alignment material through the liquid crystal injection holes A. At this time, the alignment layer is formed, and the remaining solids are induced to accumulate in the non-linear part NSLP of the microcavity400while the drying progresses to the side of the liquid crystal injection hole A. Although the solid induced to accumulate on the non-linear part NSLP is maintained, if the protrusion and depression part PTP is formed over the longitudinal light blocking member220b, this portion is a region that is not seen by the viewer, such that deleterious effects like light leakage may be reduced or prevented.

Next, a liquid crystal material including the liquid crystal molecules310are injected through the liquid crystal injection hole A, and a capping layer (not shown) covering the upper surface and the side wall of the supporting member260is formed to cove the liquid crystal injection hole A.

While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The various aspects of these different embodiments can be combined in any manner.