Patent Publication Number: US-2023132797-A1

Title: Display device

Description:
This application claims priority to Korean Patent Application No. 10-2021-0145797, filed on Oct. 28, 2021, and all the benefits accruing therefrom under 35 U.S.C. § 119, the content of which in its entirety is herein incorporated by reference. 
     BACKGROUND 
     1. Field 
     Embodiments provide generally to a display device. More particularly, embodiments relate to the display device that provides visual information. 
     2. Description of the Related Art 
     A flat panel display device is being used as a display device that replaces a cathode ray tube display due to characteristics such as light weight and thinness. Such a flat panel display device may include a liquid crystal display device and an organic light emitting display device, for example. 
     The organic light emitting display device may include a pixel defining layer defining a pixel and a spacer disposed on the pixel defining layer. In a case where the pixel defining layer and the spacer include different materials from each other, productivity may be improved by adding the number of masks and process steps. 
     SUMMARY 
     Embodiment provides a display device with improved display quality. 
     An embodiment of a display device according to the disclosure includes a substrate including a display area and a peripheral area, a driving element disposed in the display area on the substrate, a pixel electrode disposed on the driving element and connected to the driving element, a planarization layer including a first flat portion covering the driving element on the driving element and a first protrusion portion protruding in a thickness direction from an upper surface of the first flat portion adjacent to the pixel electrode, and a pixel defining layer disposed on the planarization layer. In such an embodiment, the pixel defining layer includes a bank portion, in which an opening is defined to expose a portion of the pixel electrode, and a spacer portion protruding in the thickness direction from an upper surface of the bank portion and spaced apart from the first protrusion portion in a plan view. 
     In an embodiment, each of the bank portion and the spacer portion may include a black pigment. 
     In an embodiment, each of the bank portion and the spacer portion may include a negative photosensitive material. 
     In an embodiment, the bank portion may include a second flat portion disposed on the planarization layer and a second protrusion portion protruding in the thickness direction from an upper surface of the second flat portion overlapping the first protruding portion. 
     In an embodiment, a first thickness of the second protrusion portion, which is a distance from an upper surface of the first protrusion portion to an upper surface of the second protrusion portion, may be smaller than a second thickness of the second flat portion, which is a distance from the upper surface of the first flat portion to the upper surface of the second flat portion, in a cross-sectional view. 
     In an embodiment, an upper surface of the spacer portion and an upper surface of the second protrusion portion may be located at different levels from each other in a cross-sectional view. 
     In an embodiment, the upper surface of the spacer portion may be located at a higher level than the upper surface of the second protrusion portion in the cross-sectional view. 
     In an embodiment, the planarization layer may include an organic insulating material. 
     In an embodiment, the driving element may include an active layer disposed on the substrate, a gate electrode disposed on the active layer, and a source electrode and a drain electrode, which are disposed on the gate electrode and connected to the active layer. 
     In an embodiment, the display device may further include a light emitting layer disposed on the pixel electrode and a common electrode disposed on the pixel defining layer and the light emitting layer. 
     In an embodiment, the display device may further include an encapsulation structure disposed on the common electrode, where the encapsulation structure may include an organic layer and an inorganic layer, a light blocking layer disposed on the encapsulation structure and overlapping the pixel defining layer and a reflection control layer disposed on the encapsulation structure and covering the light blocking layer. 
     An embodiment of a display device according to the disclosure includes a substrate including a display area and a peripheral area, a driving element disposed in the display area on the substrate, a pixel electrode disposed on the driving element and connected to the driving element, a planarization layer including a first flat portion covering the driving element on the driving element and a first protrusion portion protruding in a thickness direction from an upper surface of the first flat portion adjacent to the pixel electrode, and a pixel defining layer disposed on the planarization layer. In such an embodiment, the pixel defining layer includes a bank portion, in which an opening is defined to expose a portion of the pixel electrode, and a spacer portion disposed on the bank portion, including a same material as the bank portion, and spaced apart from the first protrusion portion in a plan view. 
     In an embodiment, each of the bank portion and the spacer portion may include a black pigment. 
     In an embodiment, each of the bank portion and the spacer portion may include a negative photosensitive material. 
     In an embodiment, the bank portion may include a second flat portion disposed on the planarization layer and a second protrusion portion protruding in the thickness direction from an upper surface of the second flat portion overlapping the first protruding portion. 
     In an embodiment, a first thickness of the second protrusion portion, which is a distance from an upper surface of the first protrusion portion to an upper surface of the second protrusion portion, may be smaller than a second thickness of the second flat portion, which is a distance from the upper surface of the first flat portion to the upper surface of the second flat portion, in a cross-sectional view. 
     In an embodiment, an upper surface of the spacer portion and an upper surface of the second protrusion portion may be located at different levels from each other in a cross-sectional view. 
     In an embodiment, the upper surface of the spacer portion may be located at a higher level than the upper surface of the second protrusion portion in the cross-sectional view. 
     In an embodiment, the planarization layer may include an organic insulating material. 
     In an embodiment, the display device may further include a light emitting layer disposed on the pixel electrode and a common electrode disposed on the pixel defining layer and the light emitting layer. 
     In an embodiment, the display device may further include an encapsulation structure disposed on the common electrode, where the encapsulation structure includes an organic layer and an inorganic layer, a light blocking layer disposed on the encapsulation structure and overlapping the pixel defining layer, and a reflection control layer disposed on the encapsulation structure and covering the light blocking layer. 
     In embodiments of a display device according to the invention, a planarization layer may include a first flat portion and a first protrusion protruding in a thickness direction from a upper surface of the first flat portion adjacent to a pixel electrode. In such embodiments, a bank portion disposed on the planarization layer may include a second flat portion and a second protrusion protruding from an upper surface of the second flat portion overlapping the first protrusion in the thickness direction. Accordingly, when a halftone mask is used in a photolithography process of forming the pixel defining layer including the bank portion and the spacer portion, a critical dimension (“CD”) distribution of the pixel defining layer may be improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Illustrative, non-limiting embodiments will be more clearly understood from the following detailed description in conjunction with the accompanying drawings. 
         FIG.  1    is a plan view illustrating a display device according to an embodiment. 
         FIG.  2    is a cross-sectional view taken along line I-I′ of  FIG.  1   . 
         FIG.  3    is a cross-sectional view illustrating an enlarged area ‘A’ of  FIG.  2   . 
         FIGS.  4 ,  5 ,  6 ,  7 ,  8 ,  9 , and  10    are cross-sectional views illustrating an embodiment of a method of manufacturing the display device of  FIG.  3   . 
         FIG.  11    is a block diagram illustrating an embodiment of an electronic device including the display device of  FIG.  1   . 
         FIG.  12    is a diagram illustrating an embodiment in which the electronic device of  FIG.  11    is implemented as a television. 
         FIG.  13    is a diagram illustrating an embodiment in which the electronic device of  FIG.  11    is implemented as a smartphone. 
     
    
    
     DETAILED DESCRIPTION 
     The invention now will be described more fully hereinafter with reference to the accompanying drawings, in which various embodiments are shown. This invention may, however, be embodied in many different forms, and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals refer to like elements throughout. 
     It will be understood that when an element is referred to as being “on” another element, it can be directly on the other element or intervening elements may be present therebetween. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. 
     It will be understood that, although the terms “first,” “second,” “third” etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, “a first element,” “component,” “region,” “layer” or “section” discussed below could be termed a second element, component, region, layer or section without departing from the teachings herein. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, “a”, “an,” “the,” and “at least one” do not denote a limitation of quantity, and are intended to include both the singular and plural, unless the context clearly indicates otherwise. For example, “an element” has the same meaning as “at least one element,” unless the context clearly indicates otherwise. “At least one” is not to be construed as limiting “a” or “an.” “Or” means “and/or.” As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof. 
     Furthermore, relative terms, such as “lower” or “bottom” and “upper” or “top,” may be used herein to describe one element&#39;s relationship to another element as illustrated in the Figures. It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. For example, if the device in one of the figures is turned over, elements described as being on the “lower” side of other elements would then be oriented on “upper” sides of the other elements. The term “lower,” can therefore, encompasses both an orientation of “lower” and “upper,” depending on the particular orientation of the figure. Similarly, if the device in one of the figures is turned over, elements described as “below” or “beneath” other elements would then be oriented “above” the other elements. The terms “below” or “beneath” can, therefore, encompass both an orientation of above and below. 
     “About” or “approximately” as used herein is inclusive of the stated value and means within an acceptable range of deviation for the particular value as determined by one of ordinary skill in the art, considering the measurement in question and the error associated with measurement of the particular quantity (i.e., the limitations of the measurement system). For example, “about” can mean within one or more standard deviations, or within ±30%, 20%, 10% or 5% of the stated value. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     Embodiments are described herein with reference to cross section illustrations that are schematic illustrations of idealized embodiments. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments described herein should not be construed as limited to the particular shapes of regions as illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, a region illustrated or described as flat may, typically, have rough and/or nonlinear features. Moreover, sharp angles that are illustrated may be rounded. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region and are not intended to limit the scope of the present claims. 
     Hereinafter, embodiments of the disclosure will be described in detail with reference to the accompanying drawings. 
       FIG.  1    is a plan view illustrating a display device according to an embodiment. 
     Referring to  FIG.  1   , an embodiment of the display device  10  may include a display area DA and a peripheral area PA. The display area DA may be defined as an area in which an image is displayed by generating light or adjusting transmittance of light provided from a light source. The peripheral area PA may be defined as an area that does not display an image. In an embodiment, the peripheral area PA may surround at least a portion of the display area DA. In an embodiment, for example, the peripheral area PA may entirely surround the display area DA. 
     A plurality of pixels PX may be disposed in the display area DA. In an embodiment, for example, each of the plurality of pixels PX may include a driving element (e.g., a driving element  200  of  FIG.  3   ), a light emitting element (e.g., a light emitting element  300  of  FIG.  3   ), and the like. 
     One pixel PX may display one predetermined basic color. In an embodiment, one pixel PX may be a minimum unit capable of displaying colors independent of other pixels PX. In an embodiment, for example, one pixel PX may display any one of red, green, and blue colors. 
     The plurality of pixels PX may be arranged in a matrix shape along a first direction D 1  and a second direction D 2  intersecting the first direction D 1 . In an embodiment, for example, the first direction D 1  and the second direction D 2  may be orthogonal to each other. 
     In an embodiment, the display device  10  may be an organic light emitting display device (“OLED”), but the configuration of the invention is not limited thereto. In an alternative embodiment, the display device  10  may include a liquid crystal display device (“LCD”), a field emission display device (“FED”), a plasma display device (“PDP”), or an electrophoretic display device (“EPD”). Hereinafter, for convenience of description, embodiments in which the display device  10  is an organic light emitting display device will be described in detail. 
       FIG.  2    is a cross-sectional view taken along line I-I′ of  FIG.  1   .  FIG.  3    is a cross-sectional view illustrating an enlarged area ‘A’ of  FIG.  2   . 
     Referring to  FIGS.  1 ,  2  and  3   , an embodiment of the display device  10  may include a substrate  100 , a buffer layer  110 , a gate insulating layer  130 , a driving element  200 , an interlayer insulating layer  160 , a planarization layer  170 , a light emitting element  300 , a pixel defining layer  180 , an encapsulation structure  400 , a light blocking layer  260 , a reflection control layer  270 , an overcoat layer  280  and a window member  500 . 
     In an embodiment, the driving element  200  may include an active layer  120 , a gate electrode  140 , a source electrode  161 , and a drain electrode  162 . The light emitting element  300  may include a pixel electrode  190  and a light emitting layer  210 , and a common electrode  220 . In an embodiment, the encapsulation structure  400  may include a first inorganic encapsulation layer  230 , an organic encapsulation layer  240 , and a second inorganic encapsulation layer  250 . 
     In an embodiment, as described above, the display device  10  may include the display area DA and the peripheral area PA. In such an embodiment where the display device  10  includes the display area DA and the peripheral area PA, the substrate  100  may also include the display area DA and the peripheral area PA. 
     The substrate  100  may include a transparent material or an opaque material. In an embodiment, for example, the substrate  100  may be formed of or defined by a transparent resin substrate. In such an embodiment, the transparent resin substrate may include a polyimide substrate, for example. In such an embodiment, the polyimide substrate may include a first polyimide layer, a barrier film layer, a second polyimide layer, and the like. In an alternative embodiment, the substrate  100  may include or defined by a quartz substrate, a synthetic quartz substrate, a calcium fluoride substrate, a fluorine-doped quartz substrate, a soda-lime glass substrate, a non-alkali glass substrate, or the like. These may be used alone or in combination with each other. 
     The buffer layer  110  may be disposed on the substrate  100 . The buffer layer  110  may prevent diffusion of metal atoms or impurities from the substrate  100  to the driving element  200 . In an embodiment, where a surface of the substrate  100  is not uniform, the buffer layer  110  may serve to improve a flatness of the surface of the substrate  100 . In an embodiment, for example, the buffer layer  110  may include silicon oxide, silicon nitride, or the like. These may be used alone or in combination with each other. 
     The active layer  120  may be disposed in the display area DA on the buffer layer  110 . The active layer  120  may include a metal oxide semiconductor, an inorganic semiconductor (e.g., amorphous silicon, polysilicon), or an organic semiconductor. The active layer  120  may include a source region, a drain region, and a channel region positioned between the source region and the drain region. 
     The gate insulating layer  130  may be disposed on the buffer layer  110 . The gate insulating layer  130  may cover the active layer  120 . The gate insulating layer  130  may sufficiently cover the active layer  120  on the buffer layer  110  and may have a substantially flat upper surface without creating a step difference around the active layer  120 . In an alternative embodiment, the gate insulating layer  130  may cover the active layer  120  on the buffer layer  110  and may be disposed along a profile of the active layer  120  with a uniform thickness. In an embodiment, for example, the gate insulating layer  130  may include an inorganic insulating material. In such an embodiment, the inorganic insulating material included in the gate insulating layer  130  may include silicon oxide (SiO x ), silicon nitride (SiN x ), silicon carbide (SiC x ), silicon oxynitride (SiO x N y ), silicon oxycarbide (SiO x C y ), or the like, for example. These may be used alone or in combination with each other. 
     The gate electrode  140  may be disposed in the display area DA on the gate insulating layer  130 . The gate electrode  140  may overlap the channel region of the active layer  120 . In an embodiment, for example, the gate electrode  140  may include a metal, an alloy, a metal nitride, a conductive metal oxide, a transparent conductive material, or the like. These may be used alone or in combination with each other. 
     The interlayer insulating layer  150  may be disposed on the gate insulating layer  130 . The interlayer insulating layer  150  may cover the gate electrode  140 . The interlayer insulating layer  150  may sufficiently cover the gate electrode  140  on the gate insulating layer  130  and may have a substantially flat upper surface without generating a step difference around the gate electrode  140 . In an alternative embodiment, the interlayer insulating layer  150  may cover the gate electrode  140  on the gate insulating layer  130  and may be disposed along a profile of the gate electrode  140  with a uniform thickness. In an embodiment, the interlayer insulating layer  150  may include an inorganic insulating material. In such an embodiment, the inorganic insulating material included in the interlayer insulating layer  150  may include silicon oxide, silicon nitride, silicon carbide, or the like, for example. These may be used alone or in combination with each other. 
     The source electrode  161  and the drain electrode  162  may be disposed in the display area DA on the interlayer insulating layer  150 . The source electrode  161  may be connected to the source region of the active layer  120  through a first contact hole CNT 1  defined through (e.g., formed by removing) a first portion of the gate insulating layer  130  and the interlayer insulating layer  150 . The drain electrode  162  may be connected to the drain region of the active layer  120  through a second contact hole CNT 2  defined through (e.g., formed by removing) a second portion of the gate insulating layer  130  and the interlayer insulating layer  150 . In an embodiment, for example, each of the source electrode  161  and the drain electrode  162  may include a metal, an alloy, a metal nitride, a conductive metal oxide, a transparent conductive material, or the like. These may be used alone or in combination with each other. 
     Accordingly, the driving element  200  including the active layer  120 , the gate electrode  140 , the source electrode  161 , and the drain electrode  162  may be disposed in the display area DA on the substrate  100 . 
     The planarization layer  170  may be disposed on the interlayer insulating layer  150 . The planarization layer  170  may sufficiently cover the source electrode  161  and the drain electrode  162 . In an embodiment, for example, the planarization layer  170  may have a substantially flat upper surface, and a planarization process may be added to the planarization layer  170  to implement such the flat upper surface of the planarization layer  170 . 
     The planarization layer  170  may include an inorganic insulating material or an organic insulating material. In an embodiment, the planarization layer  170  may include an organic insulating material. In such an embodiment, the organic insulating material included the planarization layer  170  may include photoresists, polyacrylic resins, polyimide resins, siloxane resins, acrylic resins, or epoxy resins, for example. These may be used alone or in combination with each other. 
     In an embodiment, the planarization layer  170  may have a multilayer structure including a first planarization layer including a substantially transparent siloxane-based resin and a second planarization layer including a substantially transparent photosensitive polyimide (“PSPI”) disposed on the first planarization layer. In such an embodiment, the first planarization layer and the second planarization layer may include different materials from each other. 
     In an embodiment, the planarization layer  170  may include a first flat portion  171  covering the driving element  200  on the driving element  200  and a first protrusion portion  172  protruding in a thickness direction (e.g., a third direction D 3 ) from an upper surface of the first flat portion  71  adjacent to the pixel electrode  190 . In such an embodiment, the first flat portion  171  and the first protrusion portion  172  may be integrally formed as a single unitary indivisible part. 
     The pixel electrode  190  may be disposed in the display area DA on the planarization layer  170 . In an embodiment, the pixel electrode  190  may be disposed on the first flat portion  171  of the planarization layer  170  to be adjacent to the first protrusion portion  172  of the planarization layer  170 . The pixel electrode  190  may be connected to the drain electrode  162  through a third contact hole CNT 3  defined through (e.g., formed by removing) a portion of the planarization layer  170 . In an embodiment, for example, the pixel electrode  190  may include a metal, an alloy, a metal nitride, a conductive metal oxide, a transparent conductive material, or the like. These may be used alone or in combination with each other 
     The pixel defining layer  180  may be disposed on the planarization layer  170  and the pixel electrode  190 . In an embodiment, the pixel defining layer  180  may include a bank portion  181  disposed on the planarization layer  170  and in which an opening is defined to expose a portion of the pixel electrode  190 , and a spacer portion  182  protruding in the thickness direction (e.g., a third direction D 3 ) from an upper surface of the bank portion  181 . During a manufacturing process of the display device  10 , the spacer portion  182  may serve to support a mask layer from collapsing when the light emitting layer  210  is formed. 
     In an embodiment, for example, the spacer portion  182  may have one of a truncated pyramid, a prism, a truncated cone, and a cylindrical shape in a cross-section. 
     In an embodiment, the spacer portion  182  may not overlap the first protrusion portion  172  of the planarization layer  170 . In an embodiment, the spacer portion  182  may not overlap the first protrusion portion  172  of the planarization layer  170  in the third direction D 3 . In such an embodiment, the spacer portion  182  may be spaced apart from the first protrusion portion  172  of the planarization layer  170  in a plan view. Herein, “in a plan view” may mean when viewed from a plan view in the third direction D 3   
     The bank portion  181  and the spacer portion  182  may be integrally formed as a single unitary indivisible part through a photolithography process using a photosensitive material as a material. In such an embodiment, the bank portion  181  and the spacer portion  182  may include a same material as each other. In an embodiment, each of the bank portion  181  and the spacer portion  182  may include a negative photosensitive material. 
     Each of the bank portion  181  and the spacer portion  182  may include an inorganic insulating material or an organic insulating material. In an embodiment, each of the bank portion  181  and the spacer portion  182  may include an organic insulating material. In such an embodiment, the organic insulating material included in each of the bank portion  181  and the spacer portion  182  may include polyacrylic resin, polyimide-based resin, acrylic resin, phenol resin, or the like, for example. These may be used alone or in combination with each other. 
     In an embodiment, each of the bank portion  181  and the spacer portion  182  may further include a black pigment or a black dye having a high light absorption rate. In an embodiment, for example, carbon black or the like may be used as the black pigment or the black dye. However, the invention is not limited thereto. 
     In an embodiment, the bank portion  181  may include a second flat portion  181   a  disposed on the planarization layer  170  and a second protrusion portion  181   b  protruding in the thickness direction (e.g., the third direction D 3 ) from an upper surface of the second flat portion  181   a  overlapping the first protrusion portion  172 . In an embodiment, for example, a thickness from the upper surface of the second flat portion  181   a  to the upper surface of the second protrusion portion  181   b  may be about 0.2 micrometer (μm) or more. 
     The upper surface of the spacer portion  182  and the upper surface of the second protrusion portion  181   b  may be located at different levels from each other. In an embodiment, the upper surface of the spacer portion  182  may be located at a higher level than the upper surface of the second protrusion portion  181   b . Alternatively, the upper surface of the spacer portion  182  may be located at a same level as the upper surface of the second protrusion portion  181   b . Here, a level of a surface may be defined based on a distance thereof from an upper surface of the substrate  100  in the thickness direction of the substrate  100  or the third direction D 3 . 
     In an embodiment, a first thickness T 1  of the second protrusion portion  181   b , which is a distance from the upper surface of the first protrusion portion  172  to the upper surface of the second protrusion portion  181   b , may be smaller than a second thickness T 2  of the second flat portion  181   a , which is a distance from the upper surface of the first flat portion  171  to the upper surface of the second flat portion  181   a.    
     The light emitting layer  210  may be disposed on the pixel electrode  190 . The light emitting layer  210  may include or be formed using at least one of light emitting materials that emit different color lights (e.g., red light, green light, blue light, and the like) according to the sub-pixels. 
     The common electrode  220  may be disposed on the pixel defining layer  180  and the light emitting layer  210 . The common electrode  220  may include a metal, an alloy, a metal nitride, a conductive metal oxide, a transparent conductive material, or the like. These may be used alone or in combination with each other. In an embodiment, for example, the common electrode  220  may be a cathode electrode. 
     Accordingly, in such an embodiment, the light emitting element  300  including the pixel electrode  190 , the light emitting layer  210 , and the common electrode  220  may be disposed in the display area DA on the substrate  100 . 
     The encapsulation structure  400  may be disposed on the common electrode  220 . The encapsulation structure  400  may include at least one inorganic layer and at least one organic layer. In an embodiment, the encapsulation structure  400  may include the first inorganic encapsulation layer  230  disposed on the common electrode  220 , the organic encapsulation layer  240  disposed on the first inorganic encapsulation layer  230 , and the second inorganic encapsulation layer  250  disposed on the organic encapsulation layer  240 . 
     The first inorganic encapsulation layer  230  may prevent the light emitting element  300  from being deteriorated due to penetration of moisture, oxygen, or the like. In addition, the first inorganic encapsulation layer  230  may also perform a function of protecting the light emitting element  300  from external impact. In an embodiment, for example, the first inorganic encapsulation layer  230  may include an inorganic insulating material having flexibility. 
     The organic encapsulation layer  240  may improve the flatness of the display device  10 , and may protect the light emitting element  300  together with the first inorganic encapsulation layer  230 . In an embodiment, for example, the organic encapsulation layer  240  may include an organic insulating material having flexibility. 
     The second inorganic encapsulation layer  250  together with the first inorganic encapsulation layer  230  may prevent the light emitting element  300  from being deteriorated due to penetration of moisture, oxygen, or the like. In addition, the second inorganic encapsulation layer  250  may protect the light emitting element  300  together with the first inorganic encapsulation layer  230  and the organic encapsulation layer  240  from external impact. In an embodiment, for example, the second inorganic encapsulation layer  250  may include an inorganic insulating material having flexibility. 
     A polarizing plate may not be disposed on the encapsulation structure  400 . In such an embodiment, the display device  10  may not include the polarizing plate. Accordingly, the light efficiency of the display device  10  may be improved. 
     The light blocking layer  260  may be disposed on the encapsulation structure  400 . The light blocking layer  260  may overlap the pixel defining layer  180 . The light blocking layer  260  may be disposed to have a plurality of openings corresponding to the light emitting layer  210 . The light blocking layer  260  may prevent visible rays of different colors implemented in the light emitting element  300  from abnormally mixing or affecting each other. In addition, the light blocking layer  260  may prevent members of the driving element  200  from being damaged by external light. 
     The light blocking layer  260  may include a light blocking material. In an embodiment, for example, the light blocking layer  260  may include a black organic material mixed with a black pigment, chromium oxide, and the like. In an embodiment, a color of the light blocking layer  260  is not limited to black, and alternatively, the light blocking layer  260  may include pigments or dyes of other colors. 
     The reflection control layer  270  may be disposed on the encapsulation structure  400 . The reflection control layer  270  may cover the light blocking layer  260 . The reflection control layer  270  may selectively pass only light of a specific wavelength, such as red light, green light, or blue light among the light emitted from the light emitting element  300 , and may absorb light of the remaining wavelengths. In addition, the reflection control layer  270  may block light reflected by external light. In an embodiment, for example, the reflection control layer  270  may include an inorganic insulating material or an organic insulating material. 
     The overcoat layer  280  may be disposed on the reflection control layer  270 . The overcoat layer  280  may prevent the reflection control layer  270  from being exposed from external moisture or air. In addition, the overcoat layer  280  may function as a planarization layer. In an embodiment, for example, the overcoat layer  280  may include an inorganic insulating material or an organic insulating material. 
     In an embodiment of the display device  10  according to the invention, the planarization layer  170  may include the first flat portion  171  and the first protrusion portion  172  protruding in the direction thickness (e.g., the third direction D 3 ) from the upper surface of the first flat portion  171  adjacent to the pixel electrode  190 . In such an embodiment, the bank portion  181  disposed on the planarization layer  170  may include the second flat portion  181   a  and the second protrusion portion  181   b  protruding in the direction thickness from the upper surface of the second flat portion  181   a  overlapping the first protrusion  172 . Accordingly, in such an embodiment, when a halftone mask is used in the photolithography process of forming the pixel defining layer  180  including the bank portion  181  and the spacer portion  182 , the degree of crosslinking of the second protrusion portion  181   b  may be improved. In such an embodiment, the distribution of a critical dimension (“CD”) of the pixel defining layer  180  may be improved. 
       FIGS.  4 ,  5 ,  6 ,  7 ,  8 ,  9 , and  10    are cross-sectional views illustrating an embodiment of a method of manufacturing the display device of  FIG.  3   . 
     Referring to  FIG.  4   , in an embodiment of a method of manufacturing the display device, the buffer layer  110  may be provided or formed on the substrate  100  including the display area DA and the peripheral area PA. The substrate  100  may include a transparent material or an opaque material. In an embodiment, for example, the substrate  100  may include a transparent resin substrate. In an embodiment, for example, the buffer layer  110  may be formed using silicon oxide, silicon nitride, or the like. 
     The active layer  120  may be formed in the display area DA on the buffer layer  110 . The active layer  120  may include a metal oxide semiconductor, an inorganic semiconductor, or an organic semiconductor. The active layer  120  may include a source region, a drain region, and a channel region positioned between the source region and the drain region. 
     The gate insulating layer  130  may be provided or formed on the buffer layer  110 . The gate insulating layer  130  may cover the active layer  120 . In an embodiment, for example, the gate insulating layer  130  may be formed using silicon oxide, silicon nitride, silicon oxide, or the like. 
     The gate electrode  140  may be provided or formed in the display area DA on the gate insulating layer  130 . The gate electrode  140  may overlap the channel region of the active layer  120 . In an embodiment, for example, the gate electrode  140  may be formed using a metal, an alloy, a metal nitride, a conductive metal oxide, a transparent conductive material, or the like. 
     The interlayer insulating layer  150  may be provided or formed on the gate insulating layer  130 . The interlayer insulating layer  150  may cover the gate electrode  140 . In an embodiment, for example, the interlayer insulating layer  150  may be formed using silicon oxide, silicon nitride, silicon carbide, or the like. 
     In an embodiment, the first contact hole CNT 1  exposing the source region of the active layer  120  may be defined through (e.g., formed by removing) a first portion of the gate insulating layer  130  and the interlayer insulating layer  150 . In such an embodiment, the second contact hole CNT 2  exposing the drain region of the active layer  120  may be defined through (e.g., formed by removing) a second portion of the gate insulating layer  130  and the interlayer insulating layer  150 . Subsequently, a metal layer may be provided or formed on the interlayer insulating layer  150  while filing the first contact hole CNT 1  and the second contact hole CNT 2 . By pattering the metal layer, the source electrode  161  and the drain electrode  162  may be formed respectively connected to the source region and the drain region. In an embodiment, for example, each of the source electrode  161  and the drain electrode  162  may be formed using a metal, an alloy, a metal nitride, a conductive metal oxide, a transparent conductive material, or the like. 
     A first photosensitive organic layer  175  may be provided or formed on the interlayer insulating layer  150 . The first photosensitive organic layer  175  may cover the source electrode  161  and the drain electrode  162 . In an embodiment, the first photosensitive organic layer  175  may be formed using an organic insulating material. In such an embodiment, since the first photosensitive organic layer  175  may be selectively removed by direct exposure without using a separate photoresist layer, a manufacturing process may be simplified. In an embodiment, for example, the first photosensitive organic layer  175  may be formed using a negative photosensitive material or a positive photosensitive material. 
     Referring to  FIGS.  5  and  6   , the planarization layer  170  including the first flat portion  171  and the first protrusion  172  protruding in the thickness direction from the upper surface of the first flat portion  171 , and the third contact hole CNT 3  exposing the drain electrode  162  may be formed through a photolithography process. 
     In an embodiment, a portion of the first photosensitive organic layer  175  may be removed by adjusting an exposure amount through a semi-transmission exposure process using a halftone mask or a slit mask. In such an embodiment, the first flat portion  171  and the first protrusion portion  172  of the planarization layer  170  may be formed, and the third contact hole CNT 3  exposing the drain electrode  162  may be formed. 
     The pixel electrode  190  may be provided or formed on the planarization layer  170  while filling the third contact hole CNT 3 . The pixel electrode  190  may be connected to the drain electrode  162  through the third contact hole CNT 3 . In an embodiment, for example, the pixel electrode  190  may be formed using a metal, an alloy, a metal nitride, a conductive metal oxide, a transparent conductive material, or the like. 
     Referring to  FIG.  7   , a second photosensitive organic layer  185  may be provided or formed on the planarization layer  170  and the pixel electrode  190 . The second photosensitive organic layer  185  may include a second flat portion  185   a  and a second protrusion portion  185   b . The second protrusion portion  185   b  may protrude from an upper surface of the second flat portion  185   a  in the thickness direction and may overlap the first protrusion portion  172  of the planarization layer  170 . 
     In an embodiment, the second photosensitive organic layer  185  may be formed using an organic insulating material. In an embodiment, the second photosensitive organic layer  185  may further include a black pigment or a black dye. In such an embodiment, since the second photosensitive organic layer  185  may be selectively removed by direct exposure without using a separate photosensitive layer, a manufacturing process may be simplified. The second photosensitive organic layer  185  may be formed using a negative photosensitive material. 
     Referring  FIGS.  8  and  9   , the pixel defining layer  180  including the bank portion  181  including the second flat portion  181   a  and the second protrusion portion  181   b  protruding in the thickness direction from the upper surface of the second flat portion  181   a , and the spacer portion  182  protruding in the thickness direction from the upper surface of the bank portion  181  may be formed through a photolithography process. 
     In an embodiment, a region in which the second photosensitive organic layer  185  is removed through the halftone mask  600  or the slit mask, a region in which the bank portion  181  is formed because the second photosensitive organic layer  185  remains, and a region in which the spacer portion  182  is formed because the second photosensitive organic layer  185  remains may be exposed to different degrees. 
     The halftone mask  600  may be divided into a first transmission portion  601  that transmits light entirely, a second transmission portion  602  that transmits light to an intermediate level, and a blocking portion  603  that substantially blocks light. The halftone mask  600  may be disposed such that the first transmission portion  601  corresponds to a region in which the spacer portion  182  is formed because the second photosensitive organic layer  185  remains, the second transmission portion  602  corresponds to a region in which the bank portion  181  is formed because the second photosensitive organic layer  185  remains, and the blocking portion  603  corresponds to a region in which the second photosensitive organic layer  185  is removed. 
     In an embodiment, the second transmission portion  602  may correspond to a region in which the second flat portion  181   a  of the bank portion  181  is formed because the second flat portion  185   a  of the second photosensitive organic layer  185  remains and a region in which the second protrusion portion  181   b  of the bank portion  181  is formed because the second protrusion portion  185   b  of the second photosensitive organic layer  185  remains, respectively. 
     The second photosensitive organic layer  185  may be removed through development in a portion where the light is blocked by the blocking portion  603 , so that the upper surface of the pixel electrode  190  may be exposed. In addition, the second photosensitive organic layer  185  may remain in a portion through which all light are transmitted by the first transmission portion  601 , so that the spacer portion  182  of the pixel defining layer  180  may be formed. The second photosensitive organic layer  185  may remain partially in a portion through which the light is transmitted through the second transmission portion  602  to an intermediate degree, so that the bank portion  181  of the pixel defining layer  180  may be formed. 
     Referring to  FIG.  10   , the light emitting layer  210  may be provided or formed on the pixel electrode  190 . The light emitting layer  210  may be formed using at least one of light emitting materials that emit different color lights from each other (e.g., red light, green light, blue light, and the like) according to the sub-pixels. 
     The common electrode  220  may be provided or formed on the pixel defining layer  180  and the light emitting layer  210 . In an embodiment, for example, the common electrode  220  may be formed using a metal, an alloy, a metal nitride, a conductive metal oxide, a transparent conductive material, or the like. 
     The encapsulation structure  400  may be provided or formed on the common electrode  220 . The encapsulation structure  400  may include the first inorganic encapsulation layer  230  formed on the common electrode  220 , the organic encapsulation layer  240  formed on the first inorganic encapsulation layer  230 , and the second inorganic encapsulation layer  250  formed on the organic encapsulation layer  240 . In an embodiment, for example, each of the first inorganic encapsulation layer  230  and the second inorganic encapsulation layer  250  may be formed using an inorganic insulating material having flexibility. The organic encapsulation layer  240  may be formed using an organic insulating material having flexibility. 
     Referring back to  FIGS.  2  and  3   , a light blocking layer  260  may be provided or formed on the second inorganic encapsulation layer  250 . The light blocking layer  260  may overlap the pixel defining layer  180 . In an embodiment, a plurality of openings may be defined or formed through the light blocking layer  260  to correspond to the light emitting layer  210 . 
     The reflection control layer  270  may be provided or formed on the second inorganic encapsulation layer  250 . The reflection control layer  270  may cover the light blocking layer  260 . In an embodiment, for example, the reflection control layer  270  may be formed using an inorganic insulating material or an organic insulating material. The overcoat layer  280  may be provided or formed on the reflection control layer  270 . In an embodiment, for example, the overcoat layer  280  may be formed using an inorganic insulating material or an organic insulating material. 
     The window member  500  may be provided or disposed on the overcoat layer  280 . The window member  500  may serve to protect the substrate  100 , the driving element  200 , the light emitting element  300 , the encapsulation structure  400 , and the like. In an embodiment, for example, the window member  500  may include or be formed using polyimide or the like. 
     Accordingly, an embodiment of the display device  10  illustrated in  FIGS.  1 ,  2 , and  3    may be manufactured through processes described above. 
       FIG.  11    is a block diagram illustrating an embodiment of an electronic device including the display device of  FIG.  1   .  FIG.  12    is a diagram illustrating an embodiment in which the electronic device of  FIG.  11    is implemented as a television.  FIG.  13    is a diagram illustrating an embodiment in which the electronic device of  FIG.  11    is implemented as a smartphone. 
     Referring to  FIGS.  11 ,  12  and  13   , in an embodiment, the electronic device  900  may include a processor  910 , a memory device  920 , a storage device  930 , an input/output (“I/O”) device  940 , a power supply  950  and a display device  960 . In such an embodiment, the display device  960  may correspond to the display device  10  described with reference to  FIGS.  1 ,  2   , and  3 . The electronic device  900  may further include various ports capable of communicating with a video card, a sound card, a memory card, a USB device, or the like. 
     In an embodiment, as illustrated in  FIG.  12   , the electronic device  900  may be implemented as a television. In an alternative embodiment, as illustrated in  FIG.  13   , the electronic device  900  may be implemented as a smart phone. However, embodiments are not limited thereto, in another alternative embodiment, the electronic device  900  may be implemented as a cellular phone, a video phone, a smart pad, a smart watch, a tablet personal computer (“PC”), a car navigation system, a computer monitor, a laptop, a head disposed (e.g., mounted) display (“HMD”), or the like. 
     The processor  910  may perform various computing functions. In an embodiment, the processor  910  may be a microprocessor, a central processing unit (“CPU”), an application processor (“AP”), or the like. The processor  910  may be coupled to other components via an address bus, a control bus, a data bus, or the like. In an embodiment, the processor  910  may be coupled to an extended bus such as a peripheral component interconnection (“PCI”) bus. 
     The memory device  920  may store data for operations of the electronic device  900 . In an embodiment, the memory device  920  may include at least one non-volatile memory device such as an erasable programmable read-only memory (“EPROM”) device, an electrically erasable programmable read-only memory (“EEPROM”) device, a flash memory device, a phase change random access memory (“PRAM”) device, a resistance random access memory (“RRAM”) device, a nano floating gate memory (“NFGM”) device, a polymer random access memory (“PoRAM”) device, a magnetic random access memory (“MRAM”) device, a ferroelectric random access memory (“FRAM”) device, or the like, and/or at least one volatile memory device such as a dynamic random access memory (“DRAM”) device, a static random access memory (“SRAM”) device, a mobile DRAM device, or the like. 
     The storage device  930  may include a solid state drive (“SSD”) device, a hard disk drive (“HDD”) device, a CD-ROM device, or the like. The I/O device  940  may include an input device such as a keyboard, a keypad, a mouse device, a touchpad, a touch-screen, or the like, and an output device such as a printer, a speaker, or the like. 
     The power supply  950  may provide power for operations of the electronic device  900 . The display device  960  may be coupled to other components via the buses or other communication links. In an embodiment, the display device  960  may be included in the I/O device  940 . 
     Embodiments of the disclosure may be applied to various electronic devices that may include a display device. In an embodiment, for example, embodiments of the disclosure may be applied to high-resolution smartphones, mobile phones, smart pads, smart watches, tablet PCs, in-vehicle navigation systems, televisions, computer monitors, notebook computers, and the like. 
     The invention should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concept of the invention to those skilled in the art. 
     While the invention has been particularly shown and described with reference to embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit or scope of the invention as defined by the following claims.