Patent Publication Number: US-2016231972-A1

Title: Display device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to, and the benefit of, Korean Patent Application No. 10-2015-0018640, filed on Feb. 6, 2015, with the Korean Intellectual Property Office (“KIPO”), the disclosure of which is incorporated herein in its entirety by reference. 
     BACKGROUND 
     1. Field 
     Embodiments of the present invention relate to a display device capable of preventing or substantially preventing detachment between a window and a display panel at a high temperature. 
     2. Description of the Related Art 
     Electronic devices that provide images to users, such as smart phones, digital cameras, laptop computers, navigation units, and televisions, include display devices for displaying images. Each display device includes a display panel for displaying images, and a window on the display panel to protect the display panel, the display panel and the window being attached to each other by an adhesive layer. 
     The display panel may be a self-emission-type display panel, such as an organic light emitting diode (“OLED”) display panel, or may be a non-emission type display panel, such as a liquid crystal display (“LCD”) panel, an electro-phoretic display panel, an electro-wetting display panel, and/or the like. 
     It is to be understood that this background section is intended to provide useful background for understanding the technology and, as such, the background section may include ideas, concepts, or recognitions that are not part of the prior art. 
     SUMMARY 
     Embodiments of the present invention are directed to a display device capable of preventing detachment between a window and a display panel. 
     According to an exemplary embodiment of the present invention, a display device includes: a display panel configured to display an image; a window on the display panel, the window including a display area configured to allow transmission of the image and a non-display area around the display area; and an adhesive layer between the display panel and the window. The window includes: a window substrate; a light blocking layer in the non-display area on the window substrate and facing the display panel; and an auxiliary adhesive layer on the light blocking layer. 
     The auxiliary adhesive layer may include a photocurable acrylate oligomer, a photocurable acrylate monomer, a rubber-based polymer, a photoinitiator, and a silane coupling agent. 
     The auxiliary adhesive layer may include: the photocurable acrylate oligomer in an amount of about 20 percent by weight (wt %) to about 40 wt %; the photocurable acrylate monomer in an amount of about 10 wt % to about 35 wt %; the rubber-based polymer in an amount of about 15 wt % to about 35 wt %; the photoinitiator in an amount of about 0.1 wt % to about 5 wt %; and the silane coupling agent in an amount of about 1 wt % to about 10 wt %. 
     The photocurable acrylate oligomer may comprise at least one of urethane (meth) acrylate oligomer, ester (meth) acrylate oligomer, ether (meth) acrylate oligomer, and epoxy (meth) acrylate oligomer. 
     The photocurable acrylate oligomer may have a weight-average molecular weight (Mw) ranging from about 5,000 to about 15,000. 
     The photocurable acrylate monomer may comprise at least one of isobornyl (meth) acrylate, lauryl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, tetrahydro-furyl (meth) acrylate, and n-octyl (meth) acrylate. 
     The rubber-based polymer may comprise at least one of polybutadiene, polyisoprene, polystyrene, and polychloroprene. 
     The rubber-based polymer may have a weight-average molecular weight (Mw) ranging from about 2,000 to about 6,000. 
     The photoinitiator may comprise at least one of 2,2-dimethoxy-1,2-diphenylethane-1-one, trimethylbenzoyl diphenylphosphine oxide, 1-hydroxycyclohexyl-benzophenone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, ethyl-2,4,6-trimethylbenzoyl phenyl phosphinate, 2-hydroxy-2-methyl-1-phenyl-1-propanone, and diphenyl (2,4,6-trimethyl benzoyl) phosphine oxide. 
     The silane coupling agent may comprise at least one of vinyl trimethoxysilane, and 3-glycidyl propyl trimethoxysilane. 
     The auxiliary adhesive layer may contact the adhesive layer. 
     The light blocking layer may include a black matrix. 
     The display device may further include a polarizing layer on the display panel. 
     The foregoing is illustrative only, and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features and aspects of the present disclosure of invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a perspective view illustrating a display device according to an exemplary embodiment; 
         FIG. 2  is a cross-sectional view taken along the line I-I′ of  FIG. 1 ; 
         FIG. 3  is a cross-sectional view illustrating a configuration of a pixel of a display panel in the area A of  FIG. 1 ; 
         FIG. 4  is a perspective view illustrating a display device according to another exemplary embodiment; and 
         FIG. 5  is a cross-sectional view taken along the line II-II′ of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION 
     Aspects and features of embodiments of the present invention and methods for achieving them will be made clear from the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and 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 scope of the invention to those skilled in the art. The present invention is merely defined by the scope of the claims. Therefore, well-known constituent elements, operations and techniques may not be described in detail in the embodiments in order to prevent the embodiments of the present invention from being obscured. Like reference numerals refer to like elements (or components) throughout the specification. 
     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 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 spirit and scope of the present invention. 
     The spatially relative terms “below”, “beneath”, “lower”, “under”, “above”, “upper”, and the like, may be used herein for ease of description to describe the relations between one element or component and another element(s) or component(s) as illustrated in the drawings. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the drawings. For example, in the case in which a device shown in the drawing is turned over, the element positioned “below”, “beneath”, or “under” other elements or features may be placed “above” the other elements or features. Accordingly, the illustrative term “below” or “under” may include both the lower and upper positions. The device may also be oriented in the other direction, and thus the spatially relative terms may be interpreted differently depending on the orientations. 
     Further, it will also be understood that when one element, component, region, layer and/or section is referred to as being “between” two elements, components, regions, layers, and/or sections, it can be the only element, component, region, layer and/or section between the two elements, components, regions, layers, and/or sections, or one or more intervening elements, components, regions, layers, and/or sections may also be present. 
     As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. Further, the use of “may” when describing embodiments of the present invention refers to “one or more embodiments of the present invention.” Also, the term “exemplary” is intended to refer to an example or illustration. 
     The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a” and “an” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprise,” “comprises,” “comprising,” “includes,” “including,” and “include,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     It will be understood that when an element or layer is referred to as being “on,” “connected to,” “coupled to,” “connected with,” “coupled with,” or “adjacent to” another element or layer, it can be “directly on,” “directly connected to,” “directly coupled to,” “directly connected with,” “directly coupled with,” or “directly adjacent to” the other element or layer, or one or more intervening elements or layers may be present. Further “connection,” “connected,” etc. may also refer to “electrical connection,” “electrically connect,” etc. depending on the context in which they are used as those skilled in the art would appreciate. When an element or layer is referred to as being “directly on,” “directly connected to,” “directly coupled to,” “directly connected with,” “directly coupled with,” or “immediately adjacent to” another element or layer, there are no intervening elements or layers present. 
     As used herein, the term “substantially,” “about,” and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent deviations in measured or calculated values that would be recognized by those of ordinary skill in the art. 
     As used herein, the terms “use,” “using,” and “used” may be considered synonymous with the terms “utilize,” “utilizing,” and “utilized,” respectively. 
     Also, any numerical range recited herein is intended to include all sub-ranges of the same numerical precision subsumed within the recited range. For example, a range of “1.0 to 10.0” or between “1.0 and 10.0” are intended to include all subranges between (and including) the recited minimum value of 1.0 and the recited maximum value of 10.0, that is, having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limitation recited herein is intended to include all lower numerical limitations subsumed therein and any minimum numerical limitation recited in this specification is intended to include ail higher numerical limitations subsumed therein. Accordingly, Applicant reserves the right to amend this specification, including the claims, to expressly recite any sub-range subsumed within the ranges expressly recited herein. All such ranges are intended to be inherently described in this specification such that amending to expressly recite any such subranges would comply with the requirements of 35 U.S.C. §112, first paragraph, and 35 U.S.C. §132(a). 
     Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which this invention pertains. 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 will not be interpreted in an ideal or excessively formal sense unless clearly defined in the present specification. 
       FIG. 1  is a perspective view illustrating a display device according to an exemplary embodiment; and  FIG. 2  is a cross-sectional view taken along the line I-I′ of  FIG. 1 . 
     In reference to  FIGS. 1 and 2 , a display device according to an exemplary embodiment includes a display panel  100 , a window  200  on the display panel  100 , and an adhesive layer  300  between the display panel  100  and the window  200 . 
     The display panel  100  generates an image, and the image generated in the display panel  100  is transmitted through the window  200  to be provided to a user. 
     The display panel  100  may be a self-emission-type display panel, such as an organic light emitting diode (“OLED”) display panel, or may be a non-emission-type display panel, such as a liquid crystal display (“LCD”) panel, an electro-phoretic display panel, an electro-wetting display panel, and/or the like. Detailed descriptions with regard to the display panel  100  are to be provided hereinafter with reference to  FIG. 3 . 
     The window  200  includes a display area DA through which the image generated in the display panel  100  is transmitted, and a non-display area NDA around the display area DA. The window  200  is on the display panel  100  to protect the display panel  100  from external impacts. 
     The window  200  includes a window substrate  210 , a light blocking layer  220  on a surface of the window substrate  210 , and an auxiliary adhesive layer  230  on the light blocking layer  220 . 
     The window substrate  210  faces the display panel  100 , and the window substrate  210  may be a transparent glass substrate or a transparent plastic substrate. 
     The window substrate  210  may be quadrangular in shape, and may have a size substantially the same as a size of the display panel  100 . However, the present invention is not limited thereto, and the window substrate  210  may have various suitable shapes, including a shape having a round corner portion, a shape having a curved corner portion, and so forth. 
     The light blocking layer  220  is on a surface of the window substrate  210  facing the display panel  100  in the non-display area NDA. The light blocking layer  220  may prevent or substantially prevent a driver, which is for driving the display panel  100 , or an accommodating unit, which is for accommodating the display panel  100 , from being externally visible. 
     The light blocking layer  220  may have various suitable colors including a black color or a white color. When having a black color, the light blocking layer  220  may include a black matrix. When having a white color, the light blocking layer  220  may include an organic insulating material, such as a white resin. Further, the light blocking layer  220  may include an opaque inorganic insulating material such as CrO x  and MoO x , or an opaque organic insulating material such as a black resin. 
     The light blocking layer  220  may have a monolayer structure having a uniform thickness, but the present invention is not limited thereto. In some embodiments, the light blocking layer  220  may have a multilayer structure in which each layer has the same or substantially the same thickness, or may have a multilayer structure in which respective layers have different thicknesses. 
     The auxiliary adhesive layer  230  is on the light blocking layer  220  in the non-display area NDA, and the auxiliary adhesive layer  230  contacts the adhesive layer  300 . The auxiliary adhesive layer  230  forms a covalent bond with a material forming the light blocking layer  220  and with a material forming the adhesive layer  300 , thus enhancing interfacial bonding force between the light blocking layer  220  and the adhesive layer  300 . 
     The auxiliary adhesive layer  230  may include a photocurable acrylate oligomer, a photocurable acrylate monomer, a rubber-based polymer, a photoinitiator, and/or a silane coupling agent. 
     More particularly, the auxiliary adhesive layer  230  may include the photocurable acrylate oligomer in an amount of about 20 wt % to about 40 wt %, the photocurable acrylate monomer in an amount of about 10 wt % to about 35 wt %, the rubber-based polymer in an amount of about 15 wt % to about 35 wt %, the photoinitiator in an amount of about 0.1 wt % to about 5 wt %, and the silane coupling agent in an amount of about 1 wt % to about 10 wt %. 
     The photocurable acrylate oligomer is cured by light, such as ultraviolet (UV) light, and may impart a cohesive force for an interfacial bonding between the light blocking layer  220  and the adhesive layer  300 . 
     The photocurable acrylate oligomer may comprise at least one of the following: urethane (meth) acrylate oligomer such as a reactant material of polyisocyanate having two or more isocyanate groups in the molecule and hydroxyalkyl (meth) acrylate; ester (meth) acrylate oligomer such as a dehydration-condensation reactant material between polyester polyol and (meth) acrylate acid; ether (meth) acrylate oligomer such as polyalkylene glycol di (meth) acrylate; and epoxy (meth) acrylate oligomer such as an additive reactant material between an epoxy resin and (meth) acrylic acid. As used herein, the term “(meth) acrylate” refers to either acrylate or methacrylate. 
     In addition, the photocurable acrylate oligomer may have a weight-average molecular weight (Mw) ranging from about 5,000 to about 15,000. 
     The photocurable acrylate monomer may serve to decrease the viscosity of the auxiliary adhesive layer  230  to allow the auxiliary adhesive layer  230  to be readily coated on the light blocking layer  220 . 
     The photocurable acrylate monomer may comprise at least one of isobornyl (meth) acrylate, lauryl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, tetrahydro-furyl (meth) acrylate, n-octyl (meth) acrylate, and a mixture thereof. More particularly, the photocurable acrylate monomer may be a mixture of isobornyl (meth) acrylate, lauryl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, tetrahydro-furyl (meth) acrylate, and n-octyl (meth) acrylate. However, a material forming the photocurable acrylate monomer is not limited thereto, and the photocurable acrylate monomer may include various suitable materials having a reactive functional group such as a (meth) acryloyl group. 
     The rubber-based polymer may serve to impart flexibility to the auxiliary adhesive layer  230 . 
     The rubber-based polymer may comprise at least one of polybutadiene, polyisoprene, polystyrene, and polychloroprene. However, a material forming the rubber-based polymer is not limited thereto, and the rubber-based polymer may include various suitable materials known in the pertinent art. 
     In addition, the rubber-based polymer may have a weight-average molecular weight (Mw) ranging from about 2,000 to about 6,000. 
     The photoinitiator is excited by light so as to serve to initiate photocuring. 
     The photoinitiator may comprise at least one of 2,2-dimethoxy-1,2-diphenylethane-1-one, trimethylbenzoyl diphenylphosphine oxide, 1-hydroxycyclohexyl-benzophenone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino propanone-1-one, ethyl-2,4,6-trimethylbenzoyl phenyl phosphinate, 2-hydroxy-2-methyl-1-phenyl-1-propanone, and diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide. However, a material forming the photoinitiator is not limited thereto, and the photoinitiator may include various suitable materials known in the pertinent art. 
     The silane coupling agent may comprise at least one of vinyl trimethoxysilane, and 3-glycidyl propyl trimethoxysilane, and the silane coupling agent may form a covalent bond with a material forming the light blocking layer  220  and a material forming the adhesive layer  300 . 
     The adhesive layer  300  may be a resin, such as a photocurable resin. In a case in which a photoinitiator included in the resin in a small amount is irradiated to light, for example, UV light, a photopolymerization reaction is initiated so that a monomer and an oligomer, which are primary elements (or components) of the resin, may quickly or instantaneously form a polymer to be cured. 
     The polarizing layer  400  is on the display panel  100 . For example, the polarizing layer  400  may be between the display panel  100  and the adhesive layer  300 . The polarizing layer  400  may convert an optical axis of light irradiated from the display panel  100 . 
     The polarizing layer  400  may be formed into a size substantially the same as the size of the display panel  100  to cover the display panel  100 . The polarizing layer  400  may have a monolayer structure, or may have a multilayer structure including a polarization film and a phase retardation film. 
     In a typical display device, a window is attached to a display panel or to a polarizing layer by an adhesive layer, and a light blocking layer on a window substrate contacts the adhesive layer. In this case, adhesion between the light blocking layer and the adhesive layer is significantly lower than adhesion between the window substrate and the adhesive layer, because surface roughness of the light blocking layer is significantly greater than surface roughness of the window substrate. 
     In particular, the adhesive layer contacting the light blocking layer may be detached from the adhesive layer at a high temperature due to low adhesion between the light blocking layer and the adhesive layer, and due to contraction of the polarizing layer, and the adhesive layer contacting the light blocking layer may contract. Accordingly, in the typical display device, detachment may occur between the window and the display panel at a high temperature. 
     In the display device according to the present invention, the auxiliary adhesive layer  230  contacting the adhesive layer  300  is on the light blocking layer  220 , such that adhesion between the light blocking layer  220  and the adhesive layer  300  is enhanced, and such that detachment, which may otherwise occur between the display panel  100  and the window  200  at a high temperature, may be prevented or substantially prevented. In particular, the auxiliary adhesive layer  230  includes a silane coupling agent that forms a covalent bond with the material forming the light blocking layer  220  and the material forming the adhesive layer  300 , such that adhesion between the light blocking layer  220  and the adhesive layer  300  may be enhanced. 
       FIG. 3  is a cross-sectional view illustrating a configuration of a pixel of the display panel  100  in the area A of  FIG. 1 . In the display device according to an exemplary embodiment, the display panel  100  is described as an OLED display panel by way of example. 
     In reference to  FIG. 3 , the first substrate  110  includes an insulating substrate including a material selected from the group consisting of: glass, quartz, ceramic, and plastic. However, an exemplary embodiment is not limited thereto, and the first substrate  110  may include a metal substrate including or being formed of stainless steel and/or the like. 
     A buffer layer  111  is on the first substrate  110 . The buffer layer  111  may serve to reduce or effectively prevent infiltration of undesired elements, and may also planarize a surface of the first substrate  110 . The buffer layer  111  may include, or may be formed of, at least one material selected from the group consisting of: silicon nitride (SiN x ), silicon oxide (SiO 2 ), and/or silicon oxynitride (SiO x N y ). However, the buffer layer  111  is not necessary, and may be omitted in consideration of the kinds and process conditions of the first substrate  110 . 
     A semiconductor layer  128  is on the buffer layer  111 . The semiconductor layer  128  may include at least one semiconductor material selected from the group consisting of polycrystalline silicon, amorphous silicon, and oxide semiconductors such as indium-gallium-zinc oxide (IGZO) and/or indium-zinc-tin oxide (IZTO). For example, in a case in which the semiconductor layer  128  is a polycrystalline silicon layer, the semiconductor layer  128  includes a channel region  128   a  that is not doped with impurities, and includes p+ doped source and drain regions  128   b  and  128   c  that are formed on respective sides of the channel region  128   a.  In this case, p-type impurities, such as boron B, may be used as a dopant ion, and in particular, B 2 H 6  may be used. Such impurities may vary depending on the kind of thin film transistor (TFT). 
     A gate insulating layer  112  is disposed on the semiconductor layer  128 . The gate insulating layer  112  includes, or is formed of, at least one selected from the group consisting of: tetraethylorthosilicate (TEOS), silicon nitride (SiN x ), and/or silicon oxide (SiO 2 ). In some embodiments, the gate insulating layer  112  may have a double-layer structure in which a SiN x  layer having a thickness of about 40 nm, and a TEOS layer having a thickness of 80 nm, are sequentially stacked. However, the gate insulating layer  112  is not limited to the aforementioned configuration, and may have various suitable structures. 
     A gate wiring is on the gate insulating layer  112 . In this case, the gate wiring includes a gate line, a gate electrode  122 , a first storage electrode  132 , and additional wirings. In addition, the gate electrode  122  overlaps at least a portion of the semiconductor layer  128 . For example, the gate electrode  122  may overlap the channel region  128   a.  The gate electrode  122  may serve to prevent or substantially prevent the channel region  128   a  from being doped with impurities when the source and drain regions  128   b  and  128   c  of the driving semiconductor layer  128  are doped with the impurities in the forming of the driving semiconductor layer  128 . 
     The first storage electrode  132  and the gate electrode  122  are formed on the same layer, and include substantially the same metal material. In this case, the metal material may include at least one of molybdenum (Mo), chromium (Cr), and tungsten (W). In some embodiments, the gate electrode  122  and the first storage electrode  132  may include molybdenum (Mo) or molybdenum alloys. 
     The interlayer insulating layer  113  is on the gate insulating layer  112  to cover the gate electrode  122 . The gate insulating layer  112  and the interlayer insulating layer  113  collectively define a source contact hole  142  exposing the source region  128   b  of the semiconductor layer  128 , and a drain contact hole  144  exposing the drain region  128   c  of the semiconductor layer  128 . The interlayer insulating layer  113  may include, or may be formed of, tetraethyl orthosilicate (TEOS), silicon nitride (SiN x ), silicon oxide (SiO 2 ), and/or the like, in a manner similar to that of the gate insulating layer  112 . However, the material forming the interlayer insulating layer  113  is not limited thereto. 
     A data wiring is disposed on the interlayer insulating layer  113 . The data wiring includes a data line, a common power line, a second storage electrode  134 , and additional wirings. The source electrode  124  and the drain electrode  126  are connected to the source region  128   b  and the drain region  128   c  of the semiconductor layer  128 , respectively, through the respective contact holes  142  and  144 . 
     As such, a thin film transistor (“TFT”)  120  includes the gate electrode  122 , the source electrode  124 , the drain electrode  126 , and the semiconductor layer  128 . The TFT  120  may have a p-type metal-oxide semiconductor (PMOS) structure using p-type impurities. However, the type of the TFT  120  is not limited thereto, and the TFT  120  may have an n-type metal-oxide semiconductor (NMOS) structure, or may have a complementary metal-oxide semiconductor (CMOS) structure. In addition, the TFT  120  may be a polycrystalline TFT, an amorphous TFT including an amorphous silicon layer, or an oxide semiconductor TFT. 
     In addition, the first storage electrode  132  and the second storage electrode  134  collectively form a capacitor  130 . In such an embodiment, the interlayer insulating layer  113  is a dielectric body of the capacitor  130 . 
     A planarization layer  114  is disposed on the interlayer insulating layer  113  to cover the data wiring. The planarization layer  114  is configured to remove a step difference and to planarize a surface therebelow to thereby improve light emission efficiency of an OLED  150 , to be described below. Further, the planarization layer  114  has a pixel electrode contact hole  114   a  for exposing a portion of the drain electrode  126 . 
     The planarization layer  114  may include, or may be formed of, at least one selected from the group consisting of: a polyacrylate resin, an epoxy resin, a phenolic resin, a polyamide resin, a polyimide resin, an unsaturated polyester resin, a poly-phenylenether resin, a poly-phenylenesulfide resin, and/or benzocyclobutene (BCB). 
     A pixel electrode  152  is on the planarization layer  114 , and the pixel electrode  152  may be an anode electrode. The pixel electrode  152  is connected to the drain electrode  126  through the contact hole  114   a  in the planarization layer  114 . 
     In addition, a pixel defining layer  160  is disposed on the planarization layer  114 , and the pixel defining layer  160  has an aperture  162  to expose the pixel electrode  152 . For example, the pixel electrode  152  corresponds to the aperture  162  of the pixel defining layer  160 . The pixel defining layer  160  may include, or may be formed of, a resin, such as a polyacrylate resin and/or a polyimide resin. 
     An organic light emitting layer  154  is on the pixel electrode  152  in the aperture  162  of the pixel defining layer  160 , and a common electrode  156  is on the pixel defining layer  160  and the organic light emitting layer  154 . 
     As such, the OLED  150  includes the pixel electrode  152 , the organic light emitting layer  154 , and the common electrode  156 . 
     One of the pixel electrode  152  and the common electrode  156  may be formed of a transparent conductive material, and the other thereof may be formed of a transflective conductive material or a reflective conductive material. Depending on the material forming the pixel electrode  152  and the common electrode  156 , the OLED display device may become a top-emission type, a bottom-emission type, or a dual-emission type. 
     For example, the transparent conductive material may be at least one selected from the group consisting of: indium tin oxides (ITO), indium zinc oxides (IZO), zinc oxide (ZnO), and/or indium oxide (In 2 O 3 ). The reflective material may be at least one selected from the group consisting of: lithium (Li), calcium (Ca), lithium fluoride/calcium (LiF/Ca), lithium fluoride/aluminum (LiF/Al), aluminum (Al), silver (Ag), magnesium (Mg), and/or gold (Au). 
     The organic light emitting layer  154  may be formed of a low molecular weight organic material or a high molecular weight organic material. The organic light emitting layer  154  may have a multilayer structure including at least one of a hole injection layer (“HIL”), a hole transporting layer (“HTL”), a light emitting layer, an electron transporting layer (“ETL”), and/or an electron injection layer (“EIL”). For example, the HIL, the HTL, the light emitting layer, the ETL, and the EIL may be sequentially stacked on the pixel electrode  152 . 
     A capping layer may further be disposed on the common electrode  156 . The capping layer may protect the OLED  150 , and may serve to allow the light generated in the organic light emitting layer  154  to be efficiently emitted externally. 
     The second substrate  170  faces the first substrate  110 , and the second substrate  170  may be attached and sealed to the first substrate  110 . A sealant may further seal the second substrate  170  and the first substrate  110 , and a space may be secured between the first substrate  110  and the second substrate  170 . 
     The second substrate  170  may include a transparent insulating substrate including one of glass, quartz, ceramic, and/or the like. However, an exemplary embodiment is not limited thereto, and the second substrate  170  may be an encapsulation member, and may have a thin film structure in which an organic layer and an inorganic layer are alternately stacked. 
     An air layer  180  may be in the space between the first substrate  110  and the second substrate  170 , more particularly, in a space between the common electrode  156  and the second substrate  170 . However, an exemplary embodiment is not limited thereto, and in lieu of the air layer  180 , a filler formed of a polymer, which is an organic material, may be in the space between the common electrode  156  and the second substrate  170 . 
       FIG. 4  is a perspective view illustrating a display device according to another exemplary embodiment, and  FIG. 5  is a cross-sectional view taken along the line II-II′ of  FIG. 4 . 
     In reference to  FIGS. 4 and 5 , the display device illustrated in  FIG. 4  has the same or substantially the same configuration as that of the display device illustrated in  FIG. 1 , with the exception of a window  200  and a polarizing layer  400 , and thus descriptions with respect to the repeated configuration may be omitted for brevity. 
     A window substrate  210  may be quadrangular in shape, and may have a size that is greater than a size of a display panel  100 . However, the present invention is not limited thereto, and the window substrate  210  may have various suitable shapes, including a shape having a round corner portion, a shape having a curved corner portion, and so forth. 
     A light blocking layer  220  is on a surface of the window substrate  210  facing the display panel  100  in a non-display area NDA, and an auxiliary adhesive layer  230  is on at least a portion of the light blocking layer  220  in the non-display area NDA. 
     The polarizing layer  400  is on the display panel  100  to cover at least a portion of the display panel  100 , and the polarizing layer  400  may have a monolayer structure or a multilayer structure including a polarization film and a phase retardation film. 
     As set forth above, adhesion between the light blocking layer and the adhesive layer is enhanced through the use of the auxiliary adhesive layer, such that detachment phenomenon occurring between the window and the display panel at a high temperature may be prevented or significantly reduced. 
     From the foregoing, it will be appreciated that various embodiments in accordance with the present disclosure have been described herein for purposes of illustration, and that various suitable modifications may be made without departing from the scope and spirit of the present invention. Accordingly, the various embodiments disclosed herein are not intended to be limiting of the true scope and spirit of the present invention. Various features of the above described and other embodiments can be mixed and matched in any manner, to produce further embodiments consistent with the invention. Thus, the present embodiments of the invention should be considered in all respects as illustrative and not restrictive, the scope of the invention to be indicated by the appended claims and their equivalents.