Abstract:
The disclosure relates to a display device, and more particularly to a display device having an improved aperture ratio and robustness. The display device may provide a display device including: a substrate; a thin film transistor formed on the substrate; a pixel electrode connected to the thin film transistor; microcavities formed on the pixel electrode, the microcavities holding liquid crystals; a roof layer formed on the microcavities and covering some sides of the microcavities; and an encapsulation layer formed on the roof layer to seal the microcavities, wherein sides of neighboring microcavities define openings are disposed in a matrix configuration.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to and the benefit of Korean Patent Application No. 10-2014-0031849 filed in the Korean Intellectual Property Office on Mar. 18, 2014, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     (a) Technical Field 
     The present invention relates to a display device, and more particularly, to a display device having an improved aperture ratio and robustness. 
     (b) Description of the Related Art 
     A liquid crystal display is a type of flat panel display device that is widely used today. Typically, a liquid crystal display includes two display panels, wherein field generating electrodes such as a pixel electrode and a common electrode sandwich a liquid crystal layer interposed therebetween. The liquid crystal display generates an electric field in the liquid crystal layer by applying a voltage to the field generating electrodes to determine orientations of liquid crystal molecules of the liquid crystal layer and control polarization of incident light, thereby displaying an image. 
     The two display panels constituting the liquid crystal display may be referred to as a thin film transistor array panel and an opposing display panel. In the thin film transistor array panel, a gate line transferring a gate signal and a data line transferring a data signal are formed to cross each other, as well as a thin film transistor connected to the gate line and the data line, a pixel electrode connected to the thin film transistor, and the like. A light blocking member, a color filter, a common electrode, and the like may be formed in the opposing display panel. In some cases, the light blocking member, the color filter, and the common electrode may be formed in the thin film transistor array panel. 
     Conventionally, a liquid crystal display uses two substrates and constituent elements are formed on the two substrates. This structure has some disadvantages, such as the display device being heavy and thick, the cost being high, and the process time being long. 
     The above information disclosed in this Background section is only for enhancement of understanding of the background of the inventive concept and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. 
     SUMMARY 
     The present inventive concept has been made in an effort to provide a display device which can decrease weight, thickness, cost, and process time by manufacturing the display device using one substrate. 
     Further, the embodiments in this disclosure provide a display device having an improved aperture ratio and a robust structure. 
     In addition, embodiments disclosed herein provide a display device including a layer of two or more liquid materials. 
     An exemplary embodiment of the inventive concept provides a display device including: a substrate; a thin film transistor formed on the substrate; a pixel electrode connected to the thin film transistor; microcavities formed on the pixel electrode, the microcavities holding liquid crystals; a roof layer formed on the microcavities and covering some sides of the microcavities; and an encapsulation layer formed on the roof layer to seal the microcavities, wherein sides of neighboring microcavities define openings that are disposed in a matrix configuration. 
     The openings may have a rhombic shape. 
     The injection holes may include: a first injection hole formed on a first side surface of one of the microcavities; and a second injection hole formed on a second side surface of the one of the microcavities, wherein the first injection hole and the second injection hole are formed to face each other. 
     The microcavities may have an octagonal shape. 
     The roof layer may cover sides of the microcavities other than the first side surface and the second side surface. 
     The substrate may be divided into a first region and a second region, and wherein at least one microcavity of the microcavities may have a first side surface and a second side surface which face each other and a third side surface and a fourth side surface which face each other, the first, second, third, and fourth side surfaces not being adjacent to each other, the first injection hole and the second injection hole are respectively formed through the first side surface and the second side surface of the microcavity at the first region, and the first injection hole and the second injection hole may respectively expose the third side surface and the fourth side surface of the microcavity at the second region. 
     A height of the roof layer located above the microcavities may be higher than that of the roof layer located between the microcavities. 
     The openings may have a polygonal shape. 
     The injection holes may include: a first injection hole extending through a part of the first side surface of the microcavity; and a second injection hole extending through an entire part of the second side surface of the microcavity. 
     An area of the first injection hole may be different from that of the second injection hole. 
     Another exemplary embodiment provides a display device including: a substrate; a thin film transistor formed on the substrate; a pixel electrode connected to the thin film transistor; microcavities formed on the pixel electrode, the microcavities holding a material layer; a roof layer formed on the microcavities and covering some sides of the microcavities; and an encapsulation layer formed on the roof layer to seal the microcavities, wherein the roof layer covers the sides of the microcavities that are not coupled to injection holes. 
     each of the microcavities may have a first side surface and a second side surface that face each other, the microcavities may include a first microcavity and a second microcavity, and the injection holes may include a first injection hole extending to the first side surface of the first microcavity, and a second injection hole extending to a second side surface of the second side surface. 
     A second side surface of the first microcavity and a first side surface of the second microcavity may be covered by the roof layer. 
     The first microcavity and the second microcavity may be adjacently disposed in a column direction and a row direction, and the first injection hole and the second injection hole may be formed to face each other with the opening therebetween. 
     The microcavities which are disposed in a row direction may be provided by repeatedly disposing one first microcavity and two microcavities according to a pattern. 
     The microcavities may further include a third microcavity having all sides covered by the roof layer. 
     The material layer may include a first liquid crystal layer made of a first liquid crystal material and a second liquid crystal layer made of a second liquid crystal material, the first liquid crystal layer and the second liquid crystal layer may fill different microcavities, and the first liquid crystal material and the second liquid crystal material may have different properties. 
     The first liquid crystal material may be different from the second liquid crystal material in response speed or transmittance. 
     The material layer may include a red organic light emitting material layer, a green organic light emitting material layer, and a blue organic light emitting material layer, and the red, green, and blue organic light emitting material layers may fill different microcavities. 
     The material layer may include a red quantum dot material layer and a green quantum dot material layer, and the red quantum dot material layer and the green quantum dot material layer may fill different microcavities. 
     In accordance with the exemplary embodiments, it is possible to provide the following effects. 
     The display device in accordance with the exemplary embodiments can improve an aperture ratio by reducing an area of the openings formed in the roof layer, and can strengthen the structure of the microcavities by reducing an area of the injection holes. 
     Further, the display device can form different liquid material layers in the adjacent microcavities by forming the injection hole in only one side surface of the microcavity and appropriately disposing the injection hole. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top plan view illustrating a display device in accordance with an exemplary embodiment of the present inventive concept. 
         FIG. 2  is an equivalent circuit diagram of one pixel of the display device in accordance with the exemplary embodiment of the present inventive concept. 
         FIG. 3  is a layout view illustrating a part of the display device in accordance with the exemplary embodiment of the present inventive concept. 
         FIG. 4  is a cross-sectional view illustrating the display device in accordance with the exemplary embodiment of the present inventive concept taken along line IV-IV of  FIG. 3 . 
         FIG. 5  is a cross-sectional view illustrating the display device in accordance with the exemplary embodiment of the present inventive concept taken along line V-V of  FIG. 3 . 
         FIG. 6  is a cross-sectional view illustrating the display device in accordance with the exemplary embodiment of the present inventive concept taken along line VI-VI of  FIG. 3 . 
         FIG. 7  and  FIG. 8  are top plan views illustrating a display device in accordance with an exemplary embodiment of the present inventive concept. 
         FIG. 9  is a top plan view illustrating the display device in accordance with the exemplary embodiment of the present inventive concept. 
         FIG. 10  is a top plan view illustrating the display device in accordance with another exemplary embodiment of the present inventive concept. 
         FIG. 11  is a top plan view illustrating the display device in accordance with yet another exemplary embodiment of the present inventive concept. 
         FIG. 12  is a top plan view illustrating the display device in accordance with yet another exemplary embodiment of the present inventive concept. 
         FIG. 13  to  FIG. 15  are stepwise top plan views showing a manufacturing method of a display device in accordance with an exemplary embodiment of the present inventive concept. 
         FIG. 16  shows a test result observed by removing a sacrificial layer from a structure in which one injection hole is formed in one microcavity. 
         FIG. 17  is a top plan view illustrating the display device in accordance with the exemplary embodiment of the present inventive concept. 
         FIG. 18  is a top plan view illustrating the display device in accordance with another exemplary embodiment of the present inventive concept. 
         FIG. 19  is a top plan view illustrating the display device in accordance with yet another exemplary embodiment of the present inventive concept. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The inventive concept will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present disclosure. 
     In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like reference numerals designate like elements throughout the specification. It will be understood that when an element such as a layer, film, region, or substrate is referred to as being “on” another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. 
     A display device in accordance with an exemplary embodiment will be briefly described with reference to  FIG. 1 . 
       FIG. 1  is a top plan view illustrating the display device in accordance with the exemplary embodiment of the present inventive concept. 
     The display device in accordance with the exemplary embodiment of the present inventive concept includes a substrate  110  formed of a material such as glass and plastic. 
     A plurality of microcavities  305  covered by roof layers  360  are formed on the substrate  110 . The microcavities  305  may have a substantially octagonal planar shape. The microcavities  305  may be disposed in rows and columns. As a result, the microcavities  305  may be disposed in a matrix form. In the embodiment of  FIG. 1 , a total of 20 microcavities  305  are formed by disposing 5 microcavities  305  in the row direction and 4 microcavities  305  in the column direction. However, this particular arrangement is not a limitation of the inventive concept, and the shape, disposal form, and number of microcavities  305  may be changed. 
     A plurality of openings  365  are formed in the roof layer  360 . No microcavity  305  is formed in regions where the openings  365  are located. The openings  365  may have a substantially rhombic planar shape. The openings  365  may be disposed in rows and columns, for example in a matrix form. In the embodiment of  FIG. 1 , a total of 12 openings  365  are formed by disposing 4 openings  365  in the row direction and 3 openings  365  in the column direction. However, this particular arrangement is not a limitation of the inventive concept, and the shape, disposal form, and number of the openings  365  may be changed. 
     The microcavities  305  are partially exposed at portions that interface the openings  365 . The roof layer  360  is formed to cover the upper surfaces and a part of side surfaces of the microcavities  305 . The roof layer  360  does not cover all of the side surfaces of the microcavities  305 . The microcavities  305  are exposed through the side surfaces of the microcavities  305  that are not covered by the roof layer  360 . As used herein, the parts of the microcavities  305  that are exposed are referred to as injection holes  307   a  and  307   b.    
     The injection holes  307   a  and  307   b  are formed at opposite edges of each of the microcavities  305 , such as the sides of neighboring octagonal microcavities  305  that form the facing sides of an opening  365 . The injection holes  307   a  and  307   b  include a first injection hole  307   a  and a second injection hole  307   b . The first injection hole  307   a  is formed to expose a first side surface of the microcavity  305 , and the second injection hole  307   b  is formed to expose a second side surface of the microcavity  305 . The first side surface and the second side surface of the microcavity  305  face each other. Accordingly, the first injection hole  307   a  and the second injection hole  307   b  are formed to face each other. 
     The roof layer  360  does not cover the first and second side surfaces of the microcavity  305  at which the injection holes  307   a  and  307   b  are respectively formed. The roof layer is formed to cover the six remaining side surfaces of the microcavity  305  except the first side surface and the second side surface. 
     An alignment material, a liquid crystal material, or the like may be injected into the microcavity  305  through the injection holes  307   a  and  307   b . In this case, the opening  365  is required to be equal to or larger than a predetermined size to facilitate easy injection of the alignment material, the liquid crystal material, or the like. In one embodiment, the predetermined size may be that a length T 1  of each diagonal of the openings  365  is about 50 μm. 
     Generally, in a display device, all openings positioned in the same row are connected to each other to have a quadrangular shape, thereby occupying a relatively large area. In the present exemplary embodiment, the openings that are adjacent in the row direction are separated from each other by microcavities  305  because the openings are disposed in a matrix configuration. Accordingly, the areas of the microcavities may be increased by reducing the areas occupied by the openings, thereby improving an aperture ratio. 
     Further, when a large amount of liquid crystal material is supplied to a specific opening, the opening may appear as a spot in the displayed image. In the present exemplary embodiment, a liquid crystal material that is supplied to one opening is injected into a microcavity located in a different row. Different color pixels are disposed at different rows, thereby reducing the formation of visual artifacts such as spots. 
     The aforementioned structure of the display device in accordance with the present exemplary embodiment is merely an example, and various modifications are feasible. For example, additional openings may be formed at parts of the roof layer  360  which covers the side surfaces of the microcavities  305 , thereby allowing adjacent microcavities  305  to be connected to each other. 
     Hereinafter, one pixel of the display device in accordance with the exemplary embodiment of the present inventive concept will be briefly described with reference to  FIG. 2 . 
       FIG. 2  is an equivalent circuit diagram of one pixel of the display device in accordance with the exemplary embodiment of the inventive concept. 
     The display device of the present exemplary embodiment includes a plurality of signal lines  121 ,  171   h , and  171   l , and a plurality of pixels PX connected to the plurality of signal lines  121 ,  171   h , and  171   l . Although not explicitly shown, a plurality of pixels PX may be arranged in a matrix including a plurality of pixel rows and a plurality of pixel columns. 
     Each pixel PX may include a first sub-pixel PXa and a second sub-pixel PXb. The first sub-pixel PXa and the second sub-pixel PXb may be disposed between adjacent signal lines  171   h  and  171   l , as in the embodiment that is shown. 
     The signal lines  121 ,  171   h , and  171   l  include a gate line  121  for transmitting a gate signal, and a first data line  171   h  and a second data line  171   l  for transmitting different data voltages. 
     The display device in accordance with the exemplary embodiment includes a first switching element Qh connected to the gate line  121  and the first data line  171   h , and a second switching element Ql connected to the gate line  121  and the second data line  171   l.    
     A first liquid crystal capacitor Clch connected with the first switching element Qh is formed in the first sub-pixel PXa, and a second liquid crystal capacitor Clcl connected with the second switching element Ql is formed in the second sub-pixel PXb. 
     A first terminal of the first switching element Qh is connected with the gate line  121 , a second terminal thereof is connected with the first data line  171   h , and a third terminal thereof is connected to the first liquid crystal capacitor Clch. 
     A first terminal of the second switching element Ql is connected with the gate line  121 , a second terminal thereof is connected with the second data line  171   l , and a third terminal thereof is connected to the second liquid crystal capacitor Clcl. 
     The operation of the liquid crystal display in accordance with the exemplary embodiment will now be described. When a gate-on voltage is applied to the gate line  121 , the first switching element Qh and the second switching element Ql connected to the gate line  121  enter a turn-on state, and the first and second liquid crystal capacitors Clch and Clcl are charged by different data voltages transmitted through the first and second data lines  171   h  and  171   l . The data voltage transmitted by the second data line  171   l  is lower than the data voltage transmitted by the first data line  171   h . Accordingly, the second liquid crystal capacitor Clcl is charged with a lower voltage than that of the first liquid crystal capacitor Clch, thereby improving side visibility. 
     Hereinafter, a structure of one pixel of the liquid crystal display in accordance with the exemplary embodiment will be described with reference to  FIGS. 3 to 6 . 
       FIG. 3  is a layout view illustrating a part of the display device in accordance with the exemplary embodiment, and  FIG. 4  is a cross-sectional view of the display device in accordance with the exemplary embodiment taken along line IV-IV of  FIG. 3 .  FIG. 5  is a cross-sectional view illustrating the display device in accordance with the exemplary embodiment taken along line V-V of  FIG. 3 , and  FIG. 6  is a cross-sectional view illustrating the display device in accordance with the exemplary embodiment taken along line VI-VI of  FIG. 3 . 
     Referring to  FIGS. 3 to 6 , the gate line  121  and a first gate electrode  124   h  and a second gate electrode  124   l  protruding from the gate line  121  are formed on the substrate  110 . 
     The gate line  121  extends in a horizontal direction, and transmits a gate signal. The gate line  121  is positioned between the two microcavities  305  that are adjacent in a column direction. The first gate electrode  124   h  and the second gate electrode  124   l  upwardly protrude in a plane view at an upper side of the gate line  121 . The first gate electrode  124   h  and the second gate electrode  124   l  are connected to each other to form one protrusion, as shown in  FIG. 3 . However, this is not a limitation of the inventive concept, and the first gate electrode  124   h  and the second gate electrode  124   l  may be modified without departing from the spirit of the concept. 
     A storage electrode line  131  and storage electrodes  133  and  135  protruding from the storage electrode line  131  may be further formed on the substrate  110 . 
     The storage electrode line  131  extends in a direction parallel to the gate line  121 , and is formed to be spaced apart from the gate line  121 . A constant voltage may be applied to the storage electrode line  131 . The storage electrode  133  protruding from the storage electrode line  131  is formed in the first subpixel area PXa. The storage electrode  135  protruding from the storage electrode line  131  in a different direction (e.g., an opposite direction) than the storage electrode  133  is formed to be adjacent to the first gate electrode  124   h  and the second gate electrode  124   l.    
     A gate insulating layer  140  is formed on the gate line  121 , the first gate electrode  124   h , the second gate electrode  124   l , the storage electrode line  131 , and the storage electrode  135 . The gate insulating layer  140  may be formed of an inorganic insulating material, such as a silicon nitride (SiNx) and a silicon oxide (SiOx). Further, the gate insulating layer  140  may be formed of a single layer or a multilayer. 
     A first semiconductor  154   h  and a second semiconductor  154   l  are formed on the gate insulating layer  140 . The first semiconductor  154   h  may be positioned on the first gate electrode  124   h , and the second semiconductor  154   l  may be positioned on the second gate electrode  124   l . The first semiconductor  154   h  may be elongated under the first data line  171   h , and the second semiconductor  154   l  may be elongated under the second data line  171   l . The first semiconductor layer  154   h  and the second semiconductor  154   l  may be formed of amorphous silicon, polycrystalline silicon, a metal oxide, or the like. 
     An ohmic contact member (not illustrated) may be formed on each of the first semiconductor  154   h  and the second semiconductor  154   l . The ohmic contact members may be made of a silicide or a material such as n+ hydrogenated amorphous silicon on which an n-type impurity is doped at a high concentration. 
     The first data line  171   h , the second data line  171   l , a first source electrode  173   h , a first drain electrode  175   h , a second source electrode  173   l , and a second drain electrode  175   l  are formed on the first semiconductor  154   h , the second semiconductor  154   l , and the gate insulating layer  140 . 
     The first data line  171   h  and the second data line  171   l  transfer a data signal, and extend in a vertical direction to cross the gate line  121  and the storage electrode  131 . The data line  171  is positioned between the two microcavities  305  which are adjacent in the row direction. 
     The first data line  171   h  and the second data line  171   l  transmit different data voltages. The data voltage transmitted by the second data line  171   l  is lower than the data voltage transmitted by the first data line  171   h.    
     The first source electrode  173   h  is formed s to protrude toward the first gate electrode  124   h  from the first data line  171   h , and the second source electrode  173   l  is formed to protrude toward the second gate electrode  124   l  from the second data line  171   l . Each of the first drain electrode  175   h  and the second drain electrode  175   l  has one wide end portion and the other rod-shaped end portion. The wide end portions of the first drain electrode  175   h  and the second drain electrode  175   l  overlap the storage electrode  135  protruding from the storage electrode line  131 . Each of the rod-shaped end portions of the first drain electrode  175   h  and the second drain electrode  175   l  is partially surrounded by the first source electrode  173   h  and the second source electrode  173   l , respectively. 
     The first and second gate electrodes  124   h  and  124   l , the first and second source electrodes  173   h  and  173   l , and the first and second drain electrodes  175   h  and  175   l  form first and second thin film transistors (TFT) Qh and Ql together with the first and second semiconductors  154   h  and  154   l , and channels of the thin film transistors are formed in the semiconductors  154   h  and  154   l  between the source electrodes  173   h  and  178   l  and the drain electrodes  175   h  and  175   l , respectively. 
     A passivation layer  180  is formed on the first semiconductor  154   h  exposed between the first data line  171   h , the second data line  171   l , the first source electrode  173   h , the first drain electrode  175   h , the first source electrode  173   h , and the first drain electrode  175   h , and the second semiconductor  154   l  exposed between the second source electrode  173   l , the drain electrode  175   l , the second source electrode  173   l , and the second drain electrode  175   l . The passivation layer  180  may be formed of an organic insulating material or an inorganic insulating material, and may be formed of a single layer or a multilayer. 
     A color filter  230  is formed in each pixel PX on the passivation layer  180 . 
     Each color filter  230  may display any one of primary colors, such as red, green, and blue. The color filter  230  is not limited to three primary colors or red, green, and blue, and may display cyan, magenta, yellow, and white-based colors. 
     A light blocking member  220  is formed in a region between adjacent color filters  230 . The light blocking member  220  is formed on a boundary of the pixel PX and the thin film transistor to prevent light leakage. The color filter  230  and the light blocking member  220  may be overlapped with each other in a partial region. 
     A first insulating layer  240  may be further formed on the color filter  230  and the light blocking member  220 . The first insulating layer  240  may be formed of an organic insulating material, and may serve to planarize the color filters  230 . 
     A second insulating layer  250  may be further formed on the first insulating layer  240 . The second insulating layer  250  may be formed of an inorganic insulating material, and may serve to protect the color filter  230  and the first insulating layer  240 . 
     A first contact hole  181   h  through which the wide end portion of the first drain electrode  175   h  is exposed and a second contact hole  181   l  through which the wide end portion of the second drain electrode  175   l  is exposed are formed in the passivation layer  180 , the first insulating layer  240 , and the second insulating layer  250 . 
     A pixel electrode  191  is formed on the second insulating layer  250 . The pixel electrode  191  may be formed of a transparent metal material, such as indium-tin oxide (ITO) and indium-zinc oxide (IZO). 
     The pixel electrode  191  may be formed of a transparent metal material, such as indium-tin oxide (ITO) and indium-zinc oxide (IZO). The first subpixel electrode  191   h  and the second subpixel electrode  191   l  are disposed on and under the pixel PX based on the gate line  121  and the storage electrode line  131 . The first sub-pixel electrode  191   h  is positioned in the first sub-pixel PXa and the second sub-pixel electrode  191   l  is positioned in the second sub-pixel PXb. 
     The first sub-pixel electrode  191   h  is connected to the first drain electrode  175   h  through the first contact hole  181   h , and the second sub-pixel electrode  191   l  is connected to the second drain electrode  175   l  through the second contact hole  181   l . Accordingly, when the first thin film transistor Qh and the second thin film transistor Ql are in an on-state, the first sub-pixel electrode  191   h  and the second sub-pixel electrode  191   l  receive different data voltages from the first drain electrode  175   h  and the second drain electrode  175   l , respectively. An electric field may be formed between the pixel electrode  191  and a common electrode  270 . 
     A general shape of each of the first sub-pixel electrode  191   h  and the second sub-pixel electrode  191   l  is a quadrangle, and the first sub-pixel electrode  191   h  and the second sub-pixel electrode  191   l  include cross-shaped stem portions formed by horizontal stem portions  193   h  and  193   l  and vertical stem portions  192   h  and  192   l  crossing the horizontal stem portions  193   h  and  193   l . Further, each of the first sub-pixel electrode  191   h  and the second sub-pixel electrode  191   l  includes a plurality of micro-branch portions  194   h  and  194   l.    
     The pixel electrode  191  is divided into four sub-regions by the horizontal stem portions  193   h  and  193   l  and the vertical stem portions  192   h  and  192   l . The micro-branch portions  194   h  and  194   l  obliquely extend from the horizontal stem portions  193   h  and  193   l  and the vertical stem portions  192   h  and  192   l , and the extension direction may form an angle of approximately 45° or 135° with the gate line  121  or the horizontal stem portions  193   h  and  193   l . Further, the directions in which the micro-branch portions  194   h  and  194   l  in two adjacent sub-regions extend may be orthogonal to each other. 
     In the present exemplary embodiment, the first sub-pixel electrode  191   h  and the second sub-pixel electrode  191   l  may further include outer stem portions surrounding outer sides of the first sub-pixel PXa and the second sub-pixel PXb, respectively. 
     The disposition form of the pixel, the structure of the thin film transistor, and the shape of the pixel electrode described above are just one embodiment and the present inventive concept is not limited thereto. 
     The common electrode  270  is formed on the pixel electrode  191  so as to be spaced apart from the pixel electrode  191  by a predetermined distance. The microcavity  305  is formed between the pixel electrode  191  and the common electrode  270 . That is, the microcavity  305  is surrounded by the pixel electrode  191  and the common electrode  270 . The common electrode  270  is formed to contact the upper surface and the side of the microcavity  305 . A width and an area of the microcavity  305  may be variously modified according to a size and resolution of the display device. 
     The common electrode  270  may be formed of a transparent metal such as indium-tin oxide (ITO) and indium-zinc oxide (IZO). A predetermined voltage may be applied to the common electrode  270 , and an electric field may be formed between the pixel electrode  191  and the common electrode  270 . 
     A first alignment layer  11  is formed on the pixel electrode  191 . The first alignment layer  11  may also be formed right on the first insulating layer  240  which is not covered by the pixel electrode  191 . 
     A second alignment layer  21  is formed under the common electrode  270  so as to face the first alignment layer  11 . 
     The first alignment layer  11  and the second alignment layer  21  may be formed as vertical alignment layers, and may be formed of an alignment material such as polyamic acid, polysiloxane, and polyimide. The first and second alignment layers  11  and  21  may be connected on a side wall of the edge of the microcavity  305 . 
     A liquid crystal layer formed of liquid crystal molecules  310  is formed in the microcavity  305  positioned between the pixel electrode  191  and the common electrode  270 . The liquid crystal molecules  310  have negative dielectric anisotropy, and may be erected in a vertical direction on the substrate  110  in the absence of an electric field, in a vertical alignment mode. 
     The first sub-pixel electrode  191   h  and the second sub-pixel electrode  191   l , to which the data voltage is applied, generate an electric field together with the common electrode  270  to determine an alignment direction of the liquid crystal molecules  310  positioned in the microcavity  305  between the two electrodes  191  and  270 . Luminance of light passing through the liquid crystal layer is changed according to the thusly determined alignment direction of the liquid crystal molecules  310 . 
     A third insulating layer  350  may be further formed on the common electrode  270 . The third insulating layer  350  is formed on the common electrode  270 . The third insulating layer  350  may be formed of an inorganic insulating material, such as a silicon nitride (SiNx) and a silicon oxide (SiOx), and may be omitted if necessary. 
     The roof layer  360  is formed on the third insulating layer  350 . As described above, a plurality of openings  365  are formed in a roof layer  360 , and may have a substantially rhombic planar shape. The roof layer  360  may have substantially the same plane pattern as the common electrode  270  and the third insulating layer  350 . Accordingly, the common electrode  270  and the third insulating layer  350  are not formed at portions at which the openings  365  of the roof layer  360  are located. 
     The roof layer  360  is formed to cover an upper surface and a side of the microcavity  305 . The roof layer  360  may be formed of an organic material. The roof layer  360  may be hardened by a hardening process to maintain the shape of the microcavity  305 . That is, the roof layer  360  is formed to be spaced apart from the pixel electrode  191  with the microcavity  305  interposed therebetween. 
     The roof layer  360  located above the microcavities  305  is separated from the substrate  110 , and the roof layer located between the adjacent microcavities  305  is attached to the substrate  110 . In the present exemplary embodiment, it is possible to make the structure of microcavities  305  more durable by increasing the area of the substrate  110  to which the roof layer  360  is attached. 
     The height of the roof layer  360  located above the microcavities  305  may be higher than the height of the roof layer  360  located between the adjacent microcavities  305 . This does not necessarily mean the thickness of the roof layer  360  is greater above the microcavities  305 ; rather, the difference in height is at least partially due to the presence of a “dip” between adjacent microcavities  305 . In fact, the roof layer  360  may be formed to have a substantially constant thickness. Recently, a curved display has been developed. In the present exemplary embodiment, the roof layer  360  located between the adjacent microcavities  305  may be formed at a lower height to reduce a force acting between the roof layers  360  located above different microcavities  305  in the curved display, thereby improving the flexibility. 
     However, as the present exemplary embodiment is not limited to a curved display application, the roof layer may be formed to have a constant height regardless of its position. In this case, the thickness of the roof layer  360  located between the microcavities  305  may be greater than that of the roof layer  360  located above the microcavities  305  to fill in the “dip.” 
     The common electrode  270  and the roof layer  360  are formed to expose the side surface of the microcavity  305 , and portions where the microcavity  305  is not covered by the common electrode  270  and the roof layer  360  form the injection holes  307   a  and  307   b . The injection holes  307   a  and  307   b  include the first injection hole  307   a , through which a lateral surface of a first edge of the microcavity  305  is exposed, and the second injection hole  307   b , through which a lateral surface of a second edge of the microcavity  305  is exposed. The first injection hole  307   a  and the second injection hole  307   b  are formed to face each other. The injection holes  307   a  and  307   b  expose side surfaces of the microcavity  305  that is adjacent to the opening  365 . The microcavities  305  are exposed by the injection holes  307   a  and  307   b , so that an alignment solution, a liquid crystal material, or the like may be injected into the microcavities  305  through the injection holes  307   a  and  307   b.    
     A fourth insulating layer  370  may be further formed on the roof layer  360 . The fourth insulating layer  370  may be made of an inorganic insulating material such as a silicon nitride (SiNx) and a silicon oxide (SiOx). The fourth insulating layer  370  may be formed to cover the top and the side of the roof layer  360 . The fourth insulating layer  370  serves to protect the roof layer  360  made of an organic material, and may be omitted if necessary. 
     An encapsulation layer  390  may be formed on the fourth insulating layer  370 . The encapsulation layer  390  is formed to cover the injection hole  307  where a part of the microcavity  305  is exposed to the outside. That is, the encapsulation layer  390  may seal the microcavity  305  so that the liquid crystal molecules  310  formed in the microcavity  305  are not discharged to the outside. The encapsulation layer  390  contacts the liquid crystal molecules  310 , and as a result, the encapsulation layer  390  may be made of a material that does not react with the liquid crystal molecules  310 . For example, the encapsulation layer  390  may be made of parylene and the like. 
     The encapsulation layer  390  may be formed by a multilayer such as a double layer and a triple layer. The double layer is configured by two layers made of different materials. 
     The triple layer is configured by three layers, and materials of adjacent layers are different from each other. For example, the encapsulation layer  390  may include a layer made of an organic insulating material or a layer made of an inorganic insulating material. 
     Although not illustrated, polarizers may be further formed on the upper and lower sides of the display device. The polarizers may be configured by a first polarizer and a second polarizer. The first polarizer may be attached onto the lower side of the substrate  110 , and the second polarizer may be attached onto the encapsulation layer  390 . 
     Hereinafter, a display device in accordance with an exemplary embodiment will be described with reference to  FIG. 7  and  FIG. 8 . 
     Since the display device in accordance with the exemplary embodiment of the present inventive concept illustrated in  FIG. 7  and  FIG. 8  is almost the same as the display device in accordance with the exemplary embodiment of the present inventive concept illustrated in  FIG. 1  to  FIG. 6 , the overlapping description thereof will be omitted. The present exemplary embodiment is different from the above exemplary embodiment where the first injection hole and the second injection hole are respectively formed at the same positions for each microcavity, in that the first injection hole and the second injection hole are respectively formed at different positions according to a position of the microcavity. This will be described later in more detail. 
       FIG. 7  and  FIG. 8  are top plan views illustrating the display device in accordance with the exemplary embodiment of the present inventive concept. 
     A plurality of microcavities  305  covered by roof layers  360  are formed on the substrate  110 . The microcavities  305  may have a substantially octagonal planar shape, and may be disposed in a matrix form. In the embodiments of  FIG. 7  and  FIG. 8 , a total of 36 microcavities  305  are formed by disposing 6 microcavities  305  in the row direction and 6 microcavities  305  in the column direction. However, this exact configuration is not a limitation of the inventive concept, and the shape, disposal form, and number of the microcavities  305  may be changed. 
     A plurality of openings  365  are formed in the roof layers  360 . The openings  365  may have a substantially rhombic planar shape, and may be disposed in a matrix form. In  FIG. 7  and  FIG. 8 , a total of 25 openings  365  are formed by disposing 5 openings  365  in the row direction and 5 openings  365  in the column direction. However, this inventive concept is not limited thereto, and the shape, disposal form, and number of the openings  365  may be changed. 
     The microcavities  305  are partially exposed to the outside at portions that contact the openings  365 . The roof layer  360  is formed to cover upper surfaces and one part of side surfaces of the microcavities  305 , and the roof layer  360  is formed to not cover the other parts of the side surfaces of the microcavities  305 . The microcavities  305  are exposed to the outside at regions at which the side surfaces of the microcavities  305  are not covered by the roof layer  360 . As such, parts at which the microcavities  305  are exposed to the outside are referred to as injection holes  307   a  and  307   b.    
     Each of the microcavities  305  has a first side surface and a second side surface that face each other, and a third side surface and a fourth side surface that face each other. For example, the microcavity  305  has an octagonal planar shape including a top side, a bottom side, a left side, and a right side. The microcavity may further include a first side that connects the top side and the left side, a second side that connects the bottom side and the right side, a third side that connects the top side and the right side, and a fourth side that connects the bottom side and the left side. In this case, a first side surface, a second side surface, a third surface, and a fourth side surface are respectively located at the first side, the second side, the third side, and the fourth side. 
     The injection holes  307   a  and  307   b  are respectively formed on opposite sides of the microcavity  305 . The injection holes  307   a  and  307   b  include a first injection hole  307   a  and a second injection hole  307   b.    
     In  FIG. 7 , in the case of the microcavities located at a first row to a third row, the first injection hole  307   a  is formed to expose a first side surface of the microcavity  305 , and the second injection hole  307   b  is formed to expose a second side surface of the microcavity  305 . In this case, the first injection hole  307   a  and the second injection hole  307   b  are formed to face each other. The roof layer  360  is formed to not cover the first side surface and the second side surface of the microcavity  305  in which the injection holes  307   a  and  307   b  are respectively formed, and is formed to cover the remaining surfaces thereof except the first side surface and the second side surface. 
     Similarly, in the case of the microcavities located at a fourth row to a sixth row, the first injection hole  307   a  is formed to expose a third side surface of the microcavity  305 , and the second injection hole  307   b  is formed to expose a fourth side surface of the microcavity  305 . In this case, the first injection hole  307   a  and the second injection hole  307   b  are also formed to face each other. The roof layer  360  is formed to not cover the third side surface and the fourth side surface of the microcavity  305  in which the injection holes  307   a  and  307   b  are respectively formed, and is formed to cover the remaining surfaces thereof except the third side surface and the fourth side surface. 
     In the present exemplary embodiment, the positions at which the injection holes  307   a  and  307   b  are formed are changed according to the position of the microcavity  305 . Accordingly, it is possible to further disperse spots by varying the formation positions of the injection holes  307   a  and  307   b  in a predetermined cycle. As described above, the positions of the injection hole  307   a  and  307   b  are changed in the cycle of 3 rows, but the present exemplary embodiment is not limited thereto. The cycle of the position change of the injection holes  307   a  and  307   b  may be variously changed. 
     The display device shown in  FIG. 8  has an inverse structure to the display device of  FIG. 8 . 
     In  FIG. 8 , in the case of the microcavities located at a first row to a third row, the first injection hole  307   a  is formed to expose a third side surface of the microcavity  305 , and the second injection hole  307   b  is formed to expose a fourth side surface of the microcavity  305 . In this case, the first injection hole  307   a  and the second injection hole  307   b  are also formed to face each other. The roof layer  360  is formed to not cover the third side surface and the fourth side surface of the microcavity  305  in which the injection holes  307   a  and  307   b  are respectively formed, and is formed to cover the remaining surfaces thereof except the third side surface and the fourth side surface. 
     Similarly, in the case of the microcavities located at a fourth row to a sixth row, the first injection hole  307   a  is formed to expose a first side surface of the microcavity  305 , and the second injection hole  307   b  is formed to expose a second side surface of the microcavity  305 . In this case, the first injection hole  307   a  and the second injection hole  307   b  are formed to face each other. The roof layer  360  is formed to avoid covering the first side surface and the second side surface of the microcavity  305  in which the injection holes  307   a  and  307   b  are respectively formed, and is formed to cover the remaining surfaces. 
     Hereinafter, a display device in accordance with another exemplary embodiment will be described with reference to  FIG. 9 . 
     Since the display device in accordance with the exemplary embodiment illustrated in  FIG. 9  is almost the same as the display device in accordance with the exemplary embodiment of  FIG. 1  to  FIG. 6 , the overlapping description thereof will be omitted. The present exemplary embodiment is different from the above exemplary embodiment where the openings of the roof layer have the rhombic planar shape, in that the openings of the roof layer have a pentagonal planar shape. This will be described later in more detail. 
       FIG. 9  is a top plan view illustrating the display device in accordance with an exemplary embodiment of the inventive concept. 
     A plurality of microcavities  305  covered by roof layers  360  are formed on the substrate  110 , and a plurality of openings  365  are formed in a roof layer  360 . The boundaries of the microcavity  305  and the opening  365  are in contact with each other. Accordingly, when the planar shape of the opening  365  is changed, the planar shape of the microcavity  305  is also changed. 
     In the present exemplary embodiment, as shown in  FIG. 9 , the openings  365  of the roof layer  360  have the pentagonal planar shape. Accordingly, the microcavities  305  have a dodecagonal planar shape. 
     The planar shape of the openings  365  of the roof layer  360  may have various polygonal shapes without being limited the rhombus or the pentagon explicitly described herein. Accordingly, the planar shape of the openings  365  may be variously changed. 
     Hereinafter, a display device in accordance with yet another exemplary embodiment will be described with reference to  FIG. 10 . 
     Since the display device in accordance with the exemplary embodiment of the present inventive concept illustrated in  FIG. 10  is almost the same as the display device in accordance with the exemplary embodiment of  FIG. 1  to  FIG. 6 , any redundant description will be omitted. The present exemplary embodiment is different from the above exemplary embodiment where there is symmetry between the first injection hole and the second injection hole, in that there is asymmetry between the first injection hole and the second injection hole. This will be described later in more detail. 
       FIG. 10  is a top plan view illustrating the display device in accordance with the exemplary embodiment of the present inventive concept. 
     The injection holes  307   a  and  307   b  are respectively formed at opposite edges of the microcavity  305 . The injection holes  307   a  and  307   b  include a first injection hole  307   a  and a second injection hole  307   b , the first injection hole  307   a  is formed to expose a first side surface of the microcavity  305 , and the second injection hole  307   b  is formed to expose a second side surface of the microcavity  305 . The first side surface and the second side surface of the microcavity  305  are formed to face each other. Accordingly, the first injection hole  307   a  and the second injection hole  307   b  are formed to face each other. 
     In the present exemplary embodiment, the first injection hole  307   a  is formed to expose a part of the first side surface of the microcavity  305 , and the second injection hole  307   b  is formed on an entire part of the side surface of the microcavity  305 . In other words, as shown in  FIG. 9 , the sidewall parts of the opening  365  that interface each of the two opposing microcavities  305  are formed into an injection hole  307   a/b . In the embodiment of  FIG. 9  where the opening  365  has a pentagonal shape but is surrounded by four microcavities  365 , Accordingly, the size of the second injection hole  307   b  is smaller than that of the first injection hole  307   a . As a result, the first injection hole  307   a  and the second injection hole  307   b  are asymmetrical with each other and different in size. 
     Hereinafter, a display device in accordance with yet another exemplary embodiment will be described with reference to  FIG. 11 . 
     Since the display device in accordance with the exemplary embodiment of  FIG. 11  is almost the same as the display device in accordance with the exemplary embodiment illustrated in  FIG. 1  to  FIG. 6 , any redundant description will be omitted. The present exemplary embodiment is different from the above exemplary embodiment in which the microcavities have a regular octagonal shape, in that the microcavities have an irregular octagonal shape with sides of different lengths. This will be described later in more detail. 
       FIG. 11  is a top plan view illustrating the display device in accordance with the exemplary embodiment of the present inventive concept. 
     A plurality of microcavities  305  covered by roof layers  360  are formed on the substrate  110 . The microcavities  305  may have a substantially octagonal shape, and may be disposed in a matrix form. 
     In the aforementioned exemplary embodiment, the microcavities  305  have a regular octagonal shape with each side of the same length. However, in the present exemplary embodiment, the microcavities  305  have the octagonal planar shape with sides of different lengths. Particularly, a left side and a right side of the octagon are formed to be longer than the other sides. Accordingly, the planar shape of the microcavities  305  may have an octagon that is elongated in one direction. A display device adopting the elongated structure of the present exemplary embodiment may be appropriate for a configuration where two subpixels are disposed in one microcavity  305 . 
     Hereinafter, a display device in accordance with yet another exemplary embodiment will be described with reference to  FIG. 12 . 
     Since the display device in accordance with the exemplary embodiment of  FIG. 12  is almost the same as the display device in accordance with the exemplary embodiment of  FIG. 1  to  FIG. 6 , any redundant description will be omitted. The present exemplary embodiment is different from the above exemplary embodiment where two injection holes are formed in one microcavity. In the embodiment of  FIG. 12 , one injection hole is formed in one microcavity. This will be described later in more detail. 
       FIG. 12  is a top plan view illustrating the display device in accordance with the exemplary embodiment of the present inventive concept. 
     A plurality of microcavities  305  covered by roof layers  360  are formed on the substrate  110 . The microcavities  305  may have a substantially quadrangular planar shape. The microcavities  305  may be disposed in a row direction and a column direction. As a result, the microcavities  305  may be disposed in a matrix form. 
     Each of the microcavities  305  includes a first microcavity  305   a  and a second microcavity  305   b . The first microcavity  305   a  and the second microcavity  305   b  are alternately arranged in the row direction and the column direction. For example, as shown in  FIG. 12 , in the case of the microcavities  305  disposed at a first row, the second microcavity  305   b , the first microcavity  305   a , the second microcavity  305   b , and the first microcavity  305   a  are repeatedly disposed in that order. Similarly, in the case of the microcavities  305  disposed at a first column, the second microcavity  305   b , the first microcavity  305   a , and the second microcavity  305   b  are repeatedly disposed in that order. 
     The openings  365  may be formed in the roof layer  360 . No microcavity  305  is formed at portions at which the openings  365  are located. The openings  365  may have a substantially bar-like planar shape. The openings  365  may be formed to extend in the row direction. The openings  365  are disposed between the adjacent microcavities  305  in the column direction. 
     The microcavities  305  are partially exposed at portions that interface the openings  365 . The roof layer  360  is formed to avoid covering a side surface of the microcavity  305 , and is formed to cover a top surface and the remaining side surfaces of the microcavity  305 . The microcavities  305  are exposed at regions where the side surfaces of the microcavities  305  are not covered by the roof layer  360 . As such, parts at which the microcavities  305  are exposed to the outside are referred to as injection holes  307   a  and  307   b.    
     The injection holes  307   a  and  307   b  include a first injection hole  307   a  and a second injection hole  307   b . One of the first injection hole  307   a  and the second injection hole  307   b  is formed at each of the microcavities  305 . Each of the microcavities  305  has a first side surface and a second side surface that face each other. The first injection hole  307   a  may be formed to expose the first side surface of the first microcavities  305   a , and the second injection hole  307   b  may be formed to expose the second side surface of the second microcavity  305   b . The second side surface of the first microcavity  305   a  is covered by the roof layer  360 , and the first side surface of the second microcavity  305   b  is covered by the roof layer  360 . 
     Since the first microcavity  305   a  and the second microcavity  305   b  are alternately arranged in the column direction, the first injection hole  307   a  and the second injection hole  307   b  are formed to face each other with the opening  365  of the roof layer  360  therebetween. 
     Liquid crystal layers having different properties may be formed in the microcavities  305  that are adjacent to each other in the row direction. For example, a first liquid crystal layer made of a first liquid crystal material may be formed in the microcavity  305  located at a first row and a first column, and a second liquid crystal layer made of a second liquid crystal material may be formed in the microcavity  305  located at the first row and a second column. In this case, the first liquid crystal material and the second liquid crystal material have different properties. For example, the first liquid crystal material and the second liquid crystal material may be different from each other in response speed or transmittance. In this case, even when one pixel at which the first liquid crystal layer is formed and another pixel at which the second liquid crystal layer are driven with the same voltage, luminance levels of light passing through the two pixels since the first liquid crystal material and the second liquid crystal material have different properties. In this way, it is possible to improve the visibility. 
     As described above, the liquid crystal layers made of liquid crystal materials having different properties have been described to be formed in different microcavities  305 , but the present inventive concept is not limited thereto. 
     Layers of different materials as well as the liquid crystal layers may be formed in the microcavities  305 . For example, an organic light emitting material layer made of an organic light emitting material may be formed therein. An organic light emitting material made of a liquid as an organic material having a self-luminance characteristic may be injected into the microcavities  305 . As another example, a quantum dot material layer made of quantum dots is possible. The quantum dots are well-known nano-material having a characteristic by which smaller particles emit light having shorter wavelengths, while lager particles emit light having longer wavelengths. Accordingly, by adjusting the size of particles, it is possible to emit light having a desired wavelength range in a visible ray region. 
     Hereinafter, a method for manufacturing a display device in accordance with an exemplary embodiment will be described with reference to  FIG. 13  to  FIG. 15 . 
       FIG. 13  to  FIG. 15  are stepwise top plan views showing a manufacturing method of a display device in accordance with an exemplary embodiment.  FIG. 13  to  FIG. 15  briefly show only some constituent elements without illustration of thin film transistors, pixel electrodes, common electrodes, and the like. The following descriptions are only related to processes for forming roof layers, microcavities, injection holes, and the like. 
     As shown in  FIG. 13 , a photosensitive organic material is first coated on a substrate  110  to form a sacrificial layer  300  through a photolithography process. In  FIG. 13 , shaded portions indicate the sacrificial layer  300 . The sacrificial layer  300  may be formed by connecting H-shaped members to each other. 
     As shown in  FIG. 14 , a roof layer  360  is formed on the sacrificial layer  300 , and the roof layer  360  is patterned to form openings  365 . Specifically, the roof layer  360  is formed to extend in a row direction, and the roof layer is patterned to form the openings  365  that extend in the row direction to have a bar-like shape. The roof layer  360  may be formed to cover a top surface and a side surface of the sacrificial layer  300 . While the sacrificial layer  300  is formed, the roof layer  360  is also formed at a portion where the photosensitive organic material is removed through the photolithography process, and the side surface of the sacrificial layer  300  is covered at the portion by the roof layer  360 . 
     As shown in  FIG. 15 , the sacrificial layer  300  is completely removed by applying a developer or a stripper solution, or by using an ashing process. Once the sacrificial layer  300  is removed, microcavities  305  are formed at the portions from which the sacrificial layer  300  has been formed. With the removal of the sacrificial layer  300 , parts that interface the openings  365  of the roof layer  360  become injection holes  307   a  and  307   b.    
     Next, liquid material is injected into the microcavities  305  by being dripped into the openings  365 . Two openings  365  are shown in  FIG. 15 , and liquid materials having different properties may be supplied to the two openings  365 . When a first liquid crystal material is supplied to a first opening  365 , the first liquid crystal material is injected into the microcavities  305  located at an odd-numbered column among the microcavities  305  located at a first row and a second row. Similarly, when a second liquid crystal material is supplied to a second opening  365 , the second liquid crystal material is injected into the microcavities  305  located at an even-numbered column among the microcavities  305  located at the second row and a third row. In this case, the liquid crystal materials having different properties are injected into the microcavities  305  that are adjacent to each other. 
     In the present exemplary embodiment, one injection hole may be formed in one microcavity. Removal of the sacrificial layer may be performed by referring to an image such as what is shown in  FIG. 16 .  FIG. 16  shows a test result observed by removing a sacrificial layer from a structure in which one injection hole is formed in one microcavity. 
     Hereinafter, a display device in accordance with an exemplary embodiment will be described with reference to  FIG. 17 . 
     Since the display device in accordance with the exemplary embodiment of  FIG. 17  is almost the same as the display device in accordance with the exemplary embodiment of  FIG. 12 , any redundant description will be omitted. The present exemplary embodiment is different from the above embodiment where the first microcavity and the second microcavity are alternatively disposed. In this embodiment, one first microcavity and two second microcavities are alternatively disposed, or vice versa. This will be described later in more detail. 
       FIG. 17  is a top plan view illustrating the display device in accordance with the exemplary embodiment of the present inventive concept. 
     A plurality of microcavities  305  covered by roof layers  360  are formed on the substrate  110 . The microcavities  305  may have a substantially quadrangular planar shape, and may be disposed in a row direction and a column direction. 
     Each of the microcavities  305  includes a first microcavity  305   a  and a second microcavity  305   b . The first microcavity  305   a  and the second microcavity  305   b  are alternately arranged in the row direction and the column direction. In  FIG. 17 , in the case of the microcavities  305  disposed at the first row, two first microcavities  305   a  and one second microcavity  305   b  are repeatedly disposed in that order. In the second row, one first microcavity  305   a  and two second microcavities  305   b  are repeatedly disposed in that order. In the third row, two first microcavities  305   a  and one second microcavity  305   b  are repeatedly disposed in that order. 
     In this case, the first microcavity  305   a  and the second microcavity  305   b  are disposed to be vertically adjacent to each other. Accordingly, the first injection hole  307   a  and the second injection hole  307   b  are formed to face each other with the opening  365  of the roof layer  360  between them. 
     Liquid crystal materials having different properties are respectively injected into the first microcavities  305   a  and the second microcavities  305   b  in the same row. For example, the liquid crystal materials having different properties are respectively injected into the microcavities in which blue pixels are formed and the microcavities in which the red and green pixels are formed. In general, a red filter and a green filter have similar thicknesses, but are different from a blue filter in thickness. Accordingly, the difference in a cell gap may be generated, but this can be compensated by injecting liquid crystal materials having different properties. 
     Hereinafter, a display device in accordance with an exemplary embodiment will be described with reference to  FIG. 18 . 
     Since the display device in accordance with the exemplary embodiment of  FIG. 18  is almost the same as the display device in accordance with the exemplary embodiment of  FIG. 12 , any redundant description will be omitted. The present exemplary embodiment is different from the above exemplary embodiment where the microcavities are formed to have the same size. In this embodiment, the microcavities may be formed to have different sizes. This will be described later in more detail. 
       FIG. 18  is a top plan view illustrating the display device in accordance with the exemplary embodiment of the present inventive concept. 
     A plurality of microcavities  305  covered by roof layers  360  are formed on the substrate  110 . The microcavities  305  may have a substantially quadrangular planar shape. 
     Each of the microcavities  305  includes a first microcavity  305   a  and a second microcavity  305   b . The first microcavity  305   a  and the second microcavity  305   b  are formed in different sizes. The first microcavity  305   a  is formed almost twice as large as the second microcavity  305   b  in this particular embodiment. 
     The openings  365  may be formed in the roof layer  360 . The openings  365  have a substantially quadrangular shape, and are disposed in a row direction and an oblique direction. 
     The first microcavity  305   a  and the second microcavity  305   b  are disposed to be vertically adjacent to each other. Accordingly, the first injection hole  307   a  formed in the first microcavity  305   a  and the second injection hole  307   b  formed in the second microcavity  305   b  are formed to face each other with the opening  365  of the roof layer  360  therebetween. 
     Liquid materials having different properties may be respectively supplied to openings  365  located at a first row, openings  365  located at a second row, and openings located at a third row. Accordingly, the liquid materials having different properties may be respectively injected into the microcavities  305  located at the first row, the microcavities  305  located at the second row, and the microcavities  305  located at the third row. As a result, material layers having different properties are formed in the three microcavities that are adjacent to each other in the row direction. 
     For example, the liquid materials having different properties may be respectively injected into the microcavities  305  in which red pixels are formed, the microcavities  305  in which green pixels are formed, and the microcavities  305  in which blue pixels are formed. The material layers may include a red organic light emitting material layer, a green organic light emitting material layer, and a blue organic light emitting material layer. The red organic light emitting material layer, the green organic light emitting material layer, and the blue organic light emitting material layer may be formed to fill different microcavities  305 . 
     Hereinafter, a display device in accordance with an exemplary embodiment will be described with reference to  FIG. 19 . 
     Since the display device in accordance with the exemplary embodiment of the present inventive concept illustrated in  FIG. 17  is almost the same as the display device in accordance with the exemplary embodiment of  FIG. 12 , any redundant description will be omitted. The present exemplary embodiment is different from the above embodiment where the injection hole is formed in all the microcavities, in that no injection hole is formed in some of the microcavities. This will be described later in more detail. 
       FIG. 19  is a top plan view illustrating the display device in accordance with the exemplary embodiment of the present inventive concept. 
     A plurality of microcavities  305  covered by roof layers  360  are formed on the substrate  110 . The microcavities  305  may have a substantially quadrangular planar shape, and the microcavities  305  may be disposed in a matrix form. 
     Each of the microcavities  305  includes a first microcavity  305   a , a second microcavity  305   b , and a third microcavity  305   c . The first microcavity  305   a , the second microcavity  305   b , and the third microcavity  305   c  are alternately arranged in a row direction. In  FIG. 17 , in the case of the microcavities  305  disposed in the first row, the third microcavity  305   c , the second microcavities  305   b , and the first microcavities  305   a  are disposed to repeat in that order. In the case of the microcavities disposed in a second row, the third microcavity  305   c , the first microcavities  305   a , and the second microcavities  305   b  are disposed to repeat in that order. In the case of the microcavities disposed in a third row, the third microcavity  305   c , the second microcavities  305   b , and the first microcavities  305   a  are disposed to repeat in that order. 
     The first injection hole  307   a  may be formed to expose a side surface of the first microcavity  305   a , and the second injection hole  307   b  may be formed to expose a second side surface of the second microcavity  305   b . No injection hole is formed in the third microcavity  305   c . A second side surface of the first microcavity  305   a  is covered by the roof layer  360 , and a first side surface of the second microcavity  305   b  is covered by the roof layer  360 . All side surfaces of the third microcavity  305   c  are covered by the roof layer  360 . 
     In this case, the first microcavity  305   a  and the second microcavity  305   b  are disposed to be vertically adjacent to each other. Accordingly, the first injection hole  307   a  and the second injection hole  307   b  are formed to face each other with the opening  365  of the roof layer  360  therebetween. 
     Two openings  365  are shown in  FIG. 19 , and liquid materials having different properties may be supplied to the two openings  365 . Accordingly, material layers having different properties are respectively formed in the microcavities located in the second row and the microcavities located in the third row. Since no injection hole is formed in the third microcavity  305 , no liquid material is injected therein. 
     For example, liquid materials having different properties may be respectively injected into the microcavities  305  in which red pixels are formed and the microcavities  305  in which green pixels are formed. The material layers may include a red quantum dot material layer and a green quantum dot material layer. The red quantum dot material layer and the green quantum dot material layer may be formed to fill different microcavities  305 . In addition, the third microcavity  305  into which no liquid material is injected can be used to emit blue color light by using a backlight formed of blue light emitting diodes. 
     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 inventive concept 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 disclosure and the appended claims.