Liquid crystal display and manufacturing method thereof

A liquid crystal display is provided. The liquid crystal display includes a substrate, a thin film transistor disposed on the substrate, a pixel electrode connected with a terminal of the thin film transistor, a microcavity disposed on the pixel electrode, the microcavity including a liquid crystal injection hole disposed at an edge of the microcavity, a supporting member disposed on the microcavity, a first hydrophobic layer disposed on an edge portion of the supporting member, and a capping layer disposed on the supporting member with the capping layer covering the liquid crystal injection hole.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2012-0132573 filed in the Korean Intellectual Property Office on Nov. 21, 2012, the entire contents of which are incorporated herein by reference.

BACKGROUND

(a) Technical Field

The present invention relates to a liquid crystal display and a manufacturing method thereof.

(b) Description of the Related Art

A liquid crystal display is commonly used in flat panel displays. The liquid crystal display may include two sheets of panels having field generating electrodes (e.g., pixel electrodes, common electrodes, or other types of electrodes) and a liquid crystal layer interposed therebetween.

When a voltage is applied to the field generating electrodes, an electric field is generated in the liquid crystal layer. The electric field determines the direction of liquid crystal molecules in the liquid crystal layer and controls polarization of incident light, so as to provide images on the liquid crystal display.

A nano crystal display (NCD) is a type of liquid crystal display. An NCD may be manufactured by forming a sacrificial layer (e.g., an organic material) on a substrate, forming a supporting member on the sacrificial layer, removing the sacrificial layer to form a cavity beneath the supporting member, and injecting liquid crystal material into the cavity.

Before injecting the liquid crystal material into the cavity, an aligning agent may be applied to the cavity in order to facilitate the arrangement and alignment of liquid crystal molecules in the cavity. After the aligning agent is applied to the cavity, drying may be required to drive out the solvent components in the aligning agent. However, in the process of drying the aligning agent, solids in the aligning agent may coalesce to form large clusters of solids in the cavity (or at the opening of the cavity). The large clusters of solids can obstruct the flow of the liquid crystal material into the cavity, and impact the arrangement and alignment of liquid crystal molecules in the cavity. As a result, the liquid crystal display may have defects arising from light leakage or transmittance deterioration.

SUMMARY

The present disclosure is directed to address at least the above problems relating to the flow of a liquid crystal material in a liquid crystal display.

According to an embodiment of the inventive concept, a liquid crystal display is provided. The liquid crystal display includes a substrate, a thin film transistor disposed on the substrate, a pixel electrode connected with a terminal of the thin film transistor, a microcavity disposed on the pixel electrode, the microcavity including a liquid crystal injection hole disposed at an edge of the microcavity, a supporting member disposed on the microcavity, a first hydrophobic layer disposed on an edge portion of the supporting member, and a capping layer disposed on the supporting member with the capping layer covering the liquid crystal injection hole.

In some embodiments, the liquid crystal display may include a second hydrophobic layer disposed between adjacent microcavities.

In some embodiments, the microcavity may include a plurality of regions, and the liquid crystal display may include a groove formed between adjacent regions, with the capping layer covering the groove.

In some embodiments, the second hydrophobic layer and the capping layer may be disposed in contact with each other in the groove.

In some embodiments, the first hydrophobic layer may include a first portion disposed at a top surface of the supporting member and a second portion extending from the first portion, with the second portion disposed on a surface of the supporting member along a lateral surface of the groove.

In some embodiments, the liquid crystal display may include an organic layer disposed on portions of the substrate, and a light blocking member disposed between adjacent organic layers, wherein the second hydrophobic layer is disposed on a portion of the light blocking member.

In some embodiments, the liquid crystal display may include a common electrode disposed on the microcavity.

In some embodiments, a surface of the pixel electrode surrounding the microcavity and a surface of the common electrode may have a hydrophilic property as a result of being subjected to hydrophilic processing.

In some embodiments, the liquid crystal display may include an alignment layer disposed between the pixel electrode and the microcavity, or between the common electrode and the microcavity.

In some embodiments, the microcavity may include a liquid crystal material.

In some embodiments, the first hydrophobic layer may include carbon, hydrogen, or fluorine.

According to another embodiment of the inventive concept, a method of manufacturing a liquid crystal display is provided. The method includes forming a thin film transistor on a substrate, forming a pixel electrode on the thin film transistor is formed, forming a sacrificial layer on the pixel electrode, forming a supporting member on the sacrificial layer, forming a microcavity by removing the sacrificial layer, wherein the microcavity includes a liquid crystal injection hole formed at an edge of the microcavity, forming a first hydrophobic layer on an edge portion of the supporting member, injecting a liquid crystal material into the microcavity, and forming a capping layer on the supporting member so as to cover the liquid crystal injection hole.

In some embodiments, the method may include forming a second hydrophobic layer between adjacent microcavities.

In some embodiments, the microcavity may include a plurality of regions, and the method may include forming a groove between adjacent regions, with the capping layer covering the groove.

In some embodiments, the method may include forming the second hydrophobic layer and the capping layer in contact with each other in the groove.

In some embodiments, forming the first hydrophobic layer may include forming a first portion disposed at a top surface of the supporting member and forming a second portion extending from the first portion, with the second portion disposed on a surface of the supporting member along a lateral surface of the groove.

In some embodiments, the method may include forming an organic layer on portions of the substrate, and forming a light blocking member between adjacent organic layers, wherein the second hydrophobic layer is formed on a portion of the light blocking member.

In some embodiments, the method may include forming a common electrode on the sacrificial layer.

In some embodiments, the method may include performing hydrophilic processing on a surface of the pixel electrode surrounding the microcavity and on a surface of the common electrode.

In some embodiments, the method may include forming an alignment layer between the pixel electrode and the microcavity, or between the common electrode and the microcavity.

DETAILED DESCRIPTION

Hereinafter, embodiments of the inventive concept will be described in detail with reference to the accompanying drawings. As those skilled in the art would realize, the described embodiments may be modified in various different ways without departing from the spirit or scope of the inventive concept.

In the drawings, the thickness of layers, films, panels, regions, etc., may have been exaggerated for clarity. It will be understood that when a layer is referred to as being “on” another layer or substrate, it can be formed directly on the other layer or substrate, or formed on the other layer or substrate with one or more intervening layers therebetween. Like reference numerals designate like elements throughout the specification.

FIG. 1is a plan view illustrating a liquid crystal display according to an exemplary embodiment of the inventive concept.FIG. 2is a cross-sectional view taken along line II-II ofFIG. 1.FIG. 3is a cross-sectional view taken along line III-III ofFIG. 1.FIG. 4is a perspective view illustrating a microcavity according to the exemplary embodiment ofFIGS. 1 to 3.

Referring toFIGS. 1 to 3, the liquid crystal display includes thin film transistors Qa, Qb, and Qc formed on a substrate110. The substrate110may be formed of transparent glass or plastic.

As shown inFIGS. 2 and 3, an organic layer230is formed on portions of the substrate110(where the thin film transistors Qa, Qb, and Qc are formed). A light blocking member220(e.g., horizontal light blocking member220aor vertical light blocking member220b) is formed on the substrate110between adjacent organic layers230. A pixel electrode191is formed on portions of the organic layer230and the light blocking member220. Referring toFIG. 1, the pixel electrode191is electrically connected to a terminal of each of the thin film transistors Qa and Qb via respective contact holes185aand185b. In some embodiments, the organic layer230may be formed being elongated in a column direction of the pixel electrode191.

In some embodiments, the organic layer230may serve as a color filter. A color filter may display one or more of the three primary colors (red, green, and blue). The color filter is not limited to the three primary colors, and may also display one of cyan, magenta, yellow, and white-based colors.

Referring toFIG. 1, adjacent organic layers230may be spaced apart from each other in a horizontal direction D and in a vertical direction that is perpendicular to the horizontal direction D.FIG. 2depicts a section of the liquid crystal display in which adjacent organic layers230are spaced apart from each other in the horizontal direction D.FIG. 3depicts a section of the liquid crystal display in which adjacent organic layers230are spaced apart from each other in the vertical direction.

Referring toFIG. 2, a vertical light blocking member220bis formed on the substrate110between the adjacent organic layers230(which are spaced apart from each other in the horizontal direction D). As shown inFIG. 2, the vertical light blocking member220bis formed overlapping the edges of the adjacent organic layers230. In some embodiments, an overlapping width between the vertical light blocking member220band the adjacent organic layers230may be substantially the same on opposite edges of the adjacent organic layers230.

Referring toFIG. 3, a horizontal light blocking member220ais formed on the substrate110between the adjacent organic layers230(which are spaced apart from each other in the vertical direction). As shown inFIG. 3, the horizontal light blocking member220ais formed overlapping the edges of the adjacent organic layers230. In some embodiments, an overlapping width between the horizontal light blocking member220aand the adjacent organic layers230may be substantially the same on opposite edges of the adjacent organic layers230.

As shown inFIGS. 2 and 3, a lower alignment layer11is formed on the pixel electrode191. The lower alignment layer11may serve as a vertical alignment layer. The lower alignment layer11may be formed of materials which are generally used as a liquid crystal alignment layer, such as polyamic acid, polysiloxane, or polyimide.

As shown inFIGS. 2 and 3, a microcavity400is formed bounded by the lower alignment layer11and an upper alignment layer21. The microcavity400may be formed in a column direction (i.e., vertical direction) of the pixel electrode191.

Referring toFIG. 3, the microcavity400has a liquid crystal injection hole A formed at an edge of the microcavity400. A liquid crystal material including liquid crystal molecules310can be injected into the microcavity400through the liquid crystal injection hole400. In some embodiments, the liquid crystal material including the liquid crystal molecules310may flow through the liquid crystal injection hole400into the microcavity400via capillary action (capillary force).

In some embodiments, a hydrophobic layer is formed between adjacent microcavities400. For example, as shown inFIG. 3, a first hydrophobic layer275ais formed on a portion of the horizontal light blocking member220abetween the adjacent microcavities400. The first hydrophobic layer275amay contain elements such as carbon, hydrogen, or fluorine. The first hydrophobic layer275amay prevent liquid crystal material from dispersing when the liquid crystal material is first dispensed (or injected) near the liquid crystal injection hole A. Specifically, a hydrophobic property of the first hydrophobic layer275aallows the liquid crystal molecules310in the liquid crystal material to maintain their original shapes when the liquid crystal material is flowing on the first hydrophobic layer275a.

As shown inFIGS. 2 and 3, a common electrode270is formed on the upper alignment layer21, and an overcoat250is formed on the common electrode270. A common voltage may be applied to the common electrode270, while a data voltage may be applied to the pixel electrode191. Together, the common electrode270and the pixel electrode191may generate an electric field that determines the orientation of the liquid crystal molecules310(located in the microcavity400between the two electrodes270and191). Also, the common electrode270and the pixel electrode191collectively constitute a capacitor that can maintain an applied voltage even after the thin film transistor (e.g., Qa, Qb, or Qc) has been turned off. The overcoat250may be formed of silicon nitride (SiNx) or silicon oxide (SiO2).

As shown inFIGS. 2 and 3, a supporting member260is formed on the overcoat250. The supporting member260may include silicon oxycarbide (SiOC), a photoresist, or other organic materials. In some embodiments, a supporting member260including photoresist may be formed using a coating method. In some preferred embodiments, a supporting member260including silicon oxycarbide (SiOC) may be formed using a chemical vapor deposition (CVD) method. The CVD method can produce silicon oxycarbide (SiOC) layers having high transmittance, low layer stress, and low layer deformation.

Referring toFIG. 3, a groove GRV may be formed between the adjacent microcavities400. In some embodiments, the groove GRV may be formed passing through a microcavity400, the upper alignment layer21, the common electrode270, the overcoat250, and the supporting member260.

Next, the microcavity400will be described in detail with reference toFIGS. 2 to 4.

Referring toFIGS. 2 to 4, the microcavity400is divided by a plurality of grooves GRV (positioned at a portion overlapping with a gate line121a) into a plurality of regions extending in the direction D of the gate line121a. The plurality of regions of the microcavity400may correspond to a plurality of pixel areas on the liquid crystal display.

A plurality of regions of the microcavity400formed in the vertical direction is referred to as a group. When a plurality of groups is formed in a row direction, the grooves GRV dividing the microcavity400may be positioned extending in the direction D of the gate line121a. As shown inFIG. 3, the liquid crystal injection hole A of the microcavity400may be formed in a region corresponding to a boundary between the groove GRV and the microcavity400.

The liquid crystal injection hole A is formed extending in the direction of the groove GRV. Referring toFIG. 2, an opening OPN may be formed between the adjacent microcavities400extending in the direction D of the gate line121a, with the opening OPN covered by the supporting member260.

As shown inFIG. 3, the liquid crystal injection hole A may be formed at an edge of the microcavity400between the upper alignment layer21and the horizontal light blocking member220a(or between the upper alignment layer21and the lower alignment layer11).

In some embodiments, the groove GRV may be formed extending in the direction D of the gate line121a. In some other embodiments, the groove GRV may be formed extending in a direction of the data line171, and a plurality of groups (plurality of regions of the microcavity400formed in the vertical direction) may be formed in a column direction. The liquid crystal injection hole A may be formed extending in the direction of the groove GRV (being formed extending in the direction of the data line171).

Referring toFIGS. 2 and 3, a passivation layer240is formed on the supporting member260. The passivation layer240may be formed of silicon nitride (SiNx) or silicon oxide (SiO2). As shown inFIG. 3, a second hydrophobic layer275bis formed on the passivation layer240. The second hydrophobic layer275bmay include a first portion275b1located above a top surface of the supporting member260and a second portion275b2extending from the first portion275b1, with the second portion275b2formed along a side surface of the supporting member260that is adjacent to the groove GRV. The second hydrophobic layer275bmay include elements such as carbon, hydrogen, or fluorine.

The second hydrophobic layer275bcan prevent mis-alignment of liquid crystal material in the liquid crystal display. First, the mis-alignment of liquid crystal material will be briefly described.

To allow the liquid crystal material to flow into the microcavity400through the liquid crystal injection hole A (e.g., via capillary action), the liquid crystal material is first dispensed (injected) onto the groove GRV. However, if the liquid crystal material is not dispensed accurately at a predetermined position, mis-alignment of the liquid crystal material may occur, resulting in dispersion of the liquid crystal material to surrounding areas. As a result, the liquid crystal material may not flow properly into the microcavity400. For example, mis-alignment of the liquid crystal material may occur if the liquid crystal material is inaccurately dispensed above a portion of the supporting member260located near the groove GRV, or on top of the passivation layer240.

As mentioned above, the second hydrophobic layer275bcan prevent mis-alignment of the liquid crystal material. Specifically, the second hydrophobic layer275bcan prevent the liquid crystal material from dispersing to another location, and can aid the flow of the liquid crystal material towards the liquid crystal injection hole A (and microcavity400). Similar to the first hydrophobic layer275a, a hydrophobic property of the second hydrophobic layer275ballows the liquid crystal molecules310in the liquid crystal material to maintain their original shapes when the liquid crystal material is flowing on the second hydrophobic layer275b.

It is noted that the second hydrophobic layer275bneed not be formed above the entire top portion of the supporting member260. In some embodiments, the second hydrophobic layer275bmay be formed above a top corner portion of the supporting member260which (the top corner portion) is adjacent to the groove GRV where the liquid crystal injection hole A is formed.

As shown inFIG. 3, a capping layer280is formed on the second hydrophobic layer275b. The capping layer280may be formed covering the first portion275b1and the second portion275b2of the second hydrophobic layer275b, with the liquid crystal injection hole A (of the microcavity400) being exposed through the groove GRV. The capping layer280may be formed of a thermosetting resin, silicon oxycarbide (SiOC), or graphene.

In some embodiments, the capping layer280is formed of graphene. The graphene layer may serve as a capping layer to cap the liquid crystal injection hole A. Graphene is suitable for use as a capping layer because it is highly impermeable to gases (such as helium). Although the liquid crystal material may contact the graphene layer, the liquid crystal material will not be contaminated because graphene comprises carbon bonds. In addition, the graphene capping layer can protect the liquid crystal material in the microcavity400from external oxygen and moisture.

In some embodiments, the liquid crystal display may be formed without having a separate upper substrate (since liquid crystal material is injected through the liquid crystal injection hole A into the microcavity400).

In some embodiments, an overcoat (not illustrated) may be formed on the capping layer280. In some embodiments, the overcoat may be formed of an inorganic layer. In other embodiments, the overcoat may be formed of an organic layer. The overcoat can help to protect the liquid crystal molecules310(that are injected into the microcavity400) from external impact. The overcoat also provides a planar layer on top of the capping layer280.

Next, a liquid crystal display according to an exemplary embodiment will be described with reference toFIGS. 1 to 3.

Referring toFIGS. 1 to 3, a plurality of gate conductors including a plurality of gate lines121a, a plurality of set-down gate lines121b, and a plurality of storage electrode lines131are formed on the substrate110(not illustrated).

The gate lines121aand the set-down gate lines121bextend primarily in the horizontal direction D to transfer gate signals to the thin film transistors Qa, Qb, or Qc. A gate line121aincludes a first gate electrode124aprotruding upward and a second gate electrode124bprotruding downward, and a set-down gate line121bincludes a third gate electrode124cprotruding upward. The first gate electrode124aand the second gate electrode124bare connected to each other to form a protrusion.

The storage electrode line131extends primarily in the horizontal direction D to transfer a predetermined voltage (such as a common voltage Vcom). The storage electrode line131includes storage electrodes129protruding both upward and downward, a pair of vertical portions134extending downward (substantially perpendicular to the gate lines121a), and a horizontal portion127connecting the pair of vertical portions134. The horizontal portion127includes a capacitor electrode137extending downward.

In some embodiments, a gate insulating layer (not illustrated) may be formed on the gate lines121a, set-down gate lines121b, and storage electrode lines131.

In some embodiments, a plurality of semiconductor strips (not illustrated) may be formed on the gate insulating layer. The semiconductor strips may be formed of amorphous or crystalline silicon. The semiconductor strips may extend primarily in a vertical direction, and may include first and second semiconductors154aand154bextending toward the first and second gate electrodes124aand124b, respectively, with the first and second semiconductors154a/154bconnected to each other, and a third semiconductor154cformed on the third gate electrode124c.

In some embodiments, a pair of ohmic contacts (not illustrated) may be formed on each of the semiconductors154a,154b, and154c. An ohmic contact may be formed of a material such as n+ hydrogenated amorphous silicon having a high dopant concentration of silicide (or another n-type impurity).

Next, 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 electrodes175cmay be formed on the pairs of ohmic contacts.

A data line171transfers a data signal and extends primarily in a vertical direction to cross a gate line121aand a set-down gate line121b. Each data line171includes a first source electrode173aand a second source electrode173bextending toward the first gate electrode124aand the second gate electrode124b, respectively, with the first source electrode173aand the second source electrode173bconnected to each other.

Each of a first drain electrode175a, second drain electrode175b, and third drain electrode175cincludes a wide end and a rod-shaped end. The rod-shaped ends of the first drain electrode175aand the second drain electrode175bare partially surrounded by the first source electrode173aand the second source electrode173b, respectively. A wide end of the first drain electrode175aextends to form a third source electrode173cwhich is curved in the shape of a letter ‘U’. A wide end177cof the third drain electrode175cis formed overlapping with the capacitor electrode137so as to form a set-down capacitor Cstd. A rod-shaped end of the third drain electrode175cis partially surrounded by the third source electrode173c.

The first gate electrode124a, the first source electrode173a, and the first drain electrode175a, together with the first semiconductor154a, form a first thin film transistor Qa. The second gate electrode124b, the second source electrode173b, and the second drain electrode175b, together with the second semiconductor154b, form a second thin film transistor Qb. The third gate electrode124c, the third source electrode173c, and the third drain electrode175c, together with the third semiconductor154c, form a third thin film transistor Qc.

The semiconductor strips including the first semiconductor154a, the second semiconductor154b, and the third semiconductor154cmay have substantially the same planar shape as the conductors171,173a,173b,173c,175a,175b, and175cand the ohmic contacts, with the exception of the channel regions formed between the source electrodes173a,173b, and173cand the drain electrodes175a,175b, and175c.

The first semiconductor154aincludes an exposed portion between the first source electrode173aand the first drain electrode175awhich is not covered by the first source electrode173aand the first drain electrode175a. The second semiconductor154bincludes an exposed portion between the second source electrode173band the second drain electrode175bwhich is not covered by the second source electrode173band the second drain electrode175b. The third semiconductor154cincludes an exposed portion between the third source electrode173cand the third drain electrode175cwhich is not covered by the third source electrode173cand the third drain electrode175c.

A lower passivation layer (not illustrated) may be formed on the conductors171,173a,173b,173c,175a,175b, and175cand the exposed portions of the semiconductors154a,154b, and154c. The lower passivation layer may be formed of an inorganic insulator such as silicon nitride or silicon oxide.

A color filter (e.g., organic layer230) may be formed on the lower passivation layer. The color filter may be formed on most regions of the lower passivation layer, except the portions of the lower passivation layer where the first thin film transistor Qa, second thin film transistor Qb, and third thin film transistor Qc are formed. The color filter may be formed being elongated in a vertical direction along a space between adjacent data lines171. In some embodiments, the color filter may be formed below the pixel electrode191and the common electrode270.

A light blocking member220may be formed on the substrate110between adjacent color filters (e.g., organic layers230) and on edge portions of the color filter. The light blocking member220may extend upward along the gate line121aand downward along the set-down gate line121b. The light blocking member220may include a first light blocking member220acovering the regions where the first thin film transistor Qa, second thin film transistor Qb, and third thin film transistor Qc are formed, and a second light blocking member220bextending along the data line171.

The light blocking member220is sometimes referred to as a black matrix and may be capable of reducing light leakage.

A plurality of contact holes185aand185bexposing the first drain electrode175aand the second drain electrode175b, respectively, may be formed in the lower passivation layer and the light blocking member220.

A pixel electrode191(including a first subpixel electrode191aand a second subpixel electrode191b) is formed on portions of the color filter and the light blocking member220. The first subpixel electrode191aand the second subpixel electrode191bare separated from each other, with the gate line121aand set-down gate line121btherebetween disposed at the upper and lower portions and adjacent to each other in a column direction. A height of the second subpixel electrode191bmay be greater than a height of the first subpixel electrode191a. In some embodiments, the height of the second subpixel electrode191bmay be about 1 to 3 times greater than the height of the first subpixel electrode191a.

The shape of each of the first subpixel electrode191aand the second subpixel electrode191bis a quadrangle. Each of the first subpixel electrode191aand the second subpixel electrode191bincludes a cross stem. The cross stem includes horizontal stems193aand193b, and vertical stems192aand192bcrossing the horizontal stems193aand193b. The first subpixel electrode191aincludes a plurality of minute branches194aand a lower protrusion197a. The second subpixel electrode191bincludes a plurality of minute branches194band an upper protrusion197b.

The pixel electrode191is divided into four subregions by the horizontal stems193aand193band the vertical stems192aand192b. The minute branches194aand194bextend obliquely from the horizontal stems193aand193band the vertical stems192aand192b. The extending directions of the minute branches194aand194bmay form an angle of about 45 degrees or 135 degrees with the gate lines121aand121bor with the horizontal stems193aand193b. The extending directions of the minute branches194aand194bof two adjacent subregions may also be perpendicular to each other.

In some embodiments, the first subpixel electrode191afurther includes an outer stem surrounding an outer portion The second subpixel electrode191bfurther includes horizontal portions positioned at the top and the bottom portions of the first subpixel electrode191a, and left and right vertical portions198positioned at the left and the right portions of the first subpixel electrode191a. The left and right vertical portions198may prevent capacitive coupling that may occur between the data line171and the first subpixel electrode191a.

The lower alignment layer11, the microcavity400, the upper alignment layer21, the common electrode270, the overcoat250, and the capping layer280are formed on or above the pixel electrode191. The aforementioned elements are the same as those described above inFIGS. 2 and 3, and further description of these elements shall be omitted.

The liquid crystal display embodiment described above is an example of a visibility structure that allows side visibility to be improved. The structure of the thin film transistor and the design of the pixel electrode are not limited to the structure described in the above embodiment, and may be modified accordingly within the spirit and scope of the inventive concept.

Next, an exemplary method of manufacturing the above liquid crystal display embodiment will be described with reference toFIGS. 5 to 14.FIGS. 5, 7, 9, and 13illustrate cross-sectional views taken along line II-II ofFIG. 1at different stages of fabrication of the liquid crystal display, andFIGS. 6, 8, 10, 11, 12, and 14illustrate cross-sectional views taken along line III-III ofFIG. 1at different stages of fabrication of the liquid crystal display.

Referring toFIGS. 5 and 6, thin film transistors Qa, Qb, and Qc (see, e.g.,FIG. 1) are formed on a substrate110. The substrate110may be formed of transparent glass or plastic. An organic layer230is formed on portions of the substrate110(where the thin film transistors Qa, Qb, and Qc are formed), with each portion corresponding to a pixel area. A light blocking member220(e.g., horizontal light blocking member220aand vertical light blocking member220b) is formed on the substrate110between adjacent organic layers230.

Next, a pixel electrode191(having minute branches) is formed on portions of the organic layer230and the light blocking member220. The pixel electrode191may be formed of a transparent conductor such as ITO or IZO.

Next, a sacrificial layer300is formed on the pixel electrode191. In some embodiments, the sacrificial layer300may be formed of silicon oxycarbide (SiOC), a photoresist, or an organic material. In some embodiments, a sacrificial layer300including silicon oxycarbide (SiOC) may be formed using a chemical vapor deposition method. In some other embodiments, a sacrificial layer300including a photoresist may be formed using a coating method. The sacrificial layer300is patterned to form a groove GRV in a direction substantially parallel to a signal line that is connected to a terminal of a thin film transistor. The sacrificial layer300is also patterned to form an opening OPN in a substantially vertical direction that is perpendicular to the groove GRV.

Referring toFIGS. 7 and 8, the common electrode270, the overcoat250, and the supporting member260are sequentially formed on the sacrificial layer300.

The common electrode270may be formed of a transparent conductor such as ITO or IZO. The overcoat250may be formed of silicon nitride (SiNx) or silicon oxide (SiO2). In some embodiments, the supporting member260may be formed of a material that is different from the sacrificial layer300.

The common electrode270, overcoat250, and supporting member260may be formed on or above the sacrificial layer300to completely fill the opening OPN. Next, as shown inFIG. 8, portions of the common electrode270, overcoat250, and supporting member260above the horizontal light blocking member220amay be removed to form a groove GRV. The groove GRV provides a passage for removing the sacrificial layer300to form a microcavity400(shown inFIG. 9).

Referring toFIGS. 9 and 10, the sacrificial layer300inFIGS. 7 and 8is removed. The sacrificial layer300may be removed using O2ashing or a wet-etching method. The removal of the sacrificial layer300results in a microcavity400having a liquid crystal injection hole A formed at an edge of the microcavity400. The microcavity400is an empty space that is formed as a result of removing the sacrificial layer300. The liquid crystal injection hole A may be formed in a direction parallel to a signal line that is connected to a terminal of the thin film transistor.

Referring toFIG. 11, plasma processing (“PP”) is performed on the microcavity400. The surface of the pixel electrode191and the surface of the common electrode270within the microcavity400may have a hydrophilic property after the plasma processing PP. The plasma processing PP includes oxygen plasma, which may be obtained from gases such as O2, O3, NO, N2O, CO, or CO2. A processing pressure during the plasma processing PP may range from about 10−3torr to 10 torr, and a processing temperature may range from about −20° C. to 80° C. Further, an inflow amount of injected gas may range from about 10 sccm (standard cubic centimeter per minute) to 10,000 sccm.

During subsequent processing, when an alignment material is injected into the groove GRV, the alignment material may enter the microcavity400through the liquid crystal injection hole A via capillary action (capillary force). As previously mentioned, after the alignment material is dispensed (or injected), the alignment material typically requires a drying step to drive out the solvents in the alignment material. However, after drying of the alignment material, the solids in the alignment material may coalesce to form large clusters of solids. The large clusters of solids can obstruct the flow of the liquid crystal material into the liquid crystal injection hole A and the microcavity400. However, if an inner wall of the microcavity400has a hydrophilic property, the solids in the alignment material can be dispersed without coalescing together after the drying of the alignment material.

By performing the plasma processing PP, the inner wall of the microcavity400may have a hydrophilic property, and the surfaces of the supporting member260or the passivation layer240may also have a hydrophilic property. As mentioned above, the hydrophilic property of these surfaces allows solids to be dispersed and prevents the solids from coalescing together after the drying of the alignment material. Accordingly, the risk of solids obstructing the flow of liquid crystal material into the liquid crystal injection hole A and microcavity400can be reduced in the above embodiments.

Referring toFIG. 12, a first hydrophobic layer275ais formed on a portion of the horizontal light blocking member220abetween the adjacent microcavities400. A second hydrophobic layer275bis formed on the passivation layer240and a side portion of the supporting member260. The second hydrophobic layer275bmay include a first portion275b1formed above a top surface of the supporting member260, and a second portion275b2extending from the first portion275b1, with the second portion275b2formed on a side surface of the supporting member260along the side of the groove GRV.

The first hydrophobic layer275aand the second hydrophobic layer275bmay include elements such as carbon, hydrogen, or fluorine, and may be formed using a chemical vapor deposition method or a sputtering method. When the first hydrophobic layer275aand the second hydrophobic layer275bare formed using a sputtering method, a processing pressure may range from about 10−2torr to 10 torr, a processing temperature may range from about 20° C. to 300° C., and an inflow amount of injected gas may range from about 10 sccm (standard cubic centimeter per minute) to 10,000 sccm.

The first hydrophobic layer275aand the second hydrophobic layer275bcan prevent liquid crystal material from dispersing when the liquid crystal material is first dispensed (or injected) onto the groove GRV. A hydrophobic property of the first hydrophobic layer275aand the second hydrophobic layer275balso allows the liquid crystal molecules310in the liquid crystal material to maintain their original shapes when the liquid crystal material is flowing on the first hydrophobic layer275aand/or the second hydrophobic layer275b.

Referring toFIGS. 13 and 14, alignment layers11and21are respectively formed on the pixel electrode191and the common electrode270by dispensing (injecting) an alignment material onto the groove GRV, into the liquid crystal injection hole A and microcavity400. After the alignment material is injected, the alignment material flows through the liquid crystal injection hole A into the microcavity400via capillary action (capillary force). In some embodiments, the alignment layers11and21are formed after the hydrophobic layers275aand275bhave been formed. In yet other embodiments, the hydrophobic layers275aand275bare formed after plasma processing PP, and after the alignment layers11and21have been formed.

As previously mentioned, the dispensed liquid crystal material (including the liquid crystal molecules310) can flow into the microcavity400via capillary action (capillary force) through the groove GRV and the liquid crystal injection hole A. Since the first hydrophobic layer275ais formed in a region adjacent to the liquid crystal injection hole A, the liquid crystal material is not dispersed when the liquid crystal material is dispensed (or injected) onto the groove GRV. Also, as previously mentioned, a hydrophobic property of the first hydrophobic layer275aallows the liquid crystal molecules310in the liquid crystal material to maintain their original shapes when the liquid crystal material is flowing on the first hydrophobic layer275a. The second hydrophobic layer275bis formed above a top surface of the supporting member260and located near the groove GRV. Accordingly, even if mis-alignment occurs during the dispense of the liquid crystal material, the second hydrophobic layer275bmay still guide the liquid crystal material toward the liquid crystal injection hole A, while maintaining the original shape of the liquid crystal molecules310as the liquid crystal material is flowing on the second hydrophobic layer275b.

Next, a capping layer280is formed to cover the liquid crystal injection hole A according to the embodiments described inFIGS. 2 and 3. The capping layer280covers the top and the side walls of the supporting member260, and also covers the liquid crystal injection hole A being exposed by the groove GRV. The first hydrophobic layer275aand the capping layer280may be formed in contact with each other in the groove GRV. As previously mentioned, the capping layer280may be formed of a thermosetting resin, silicon oxycarbide (SiOC), or graphene.

While the inventive concept has been described with reference to some embodiments, it is to be understood that the inventive concept is not limited to the disclosed embodiments, and is intended to cover various modifications and equivalent arrangements within the spirit and scope of the inventive concept.