Patent Publication Number: US-2022216435-A1

Title: Display device having ultraviolet light blocking properties

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a Division of co-pending U.S. patent application Ser. No. 16/268,147, filed on Feb. 5, 2019, which claims priority under 35 USC § 119 to Korean Patent Application No. 10-2018-0027537, filed on Mar. 8, 2018 in the Korean Intellectual Property Office (KIPO), the entire disclosures of which are incorporated by reference herein. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a display device and, more specifically, to a display device having ultraviolet light blocking properties. 
     DISCUSSION OF THE RELATED ART 
     A display device is a device that generates an image that can be viewed by a user. Display devices have been incorporated into a wide variety of electronic products such as information devices, for example, smartphones and the like. Among the various types of display devices commonly in use, an organic light emitting diode (OLED) display device is attracting attention as a display device having excellent characteristics, such as a slim profile, light weight, and low power consumption. 
     As outdoor use of information devices such as smartphones increases, display devices may be exposed to sunlight for longer periods of time. Furthermore, ultraviolet light may be used in various processes that are part of manufacturing display devices. Exposure to ultraviolet light may damage various components of the display device. 
     SUMMARY 
     A display device includes a substrate, a thin film transistor disposed on the substrate, and a display element electrically connected to the thin film transistor. The substrate includes a first substrate layer, a second substrate layer disposed on the first substrate layer, a first barrier layer disposed between the first substrate layer and the second substrate layer, and a first ultraviolet light blocking layer disposed between the first substrate layer and the second substrate layer. 
     A display device includes a substrate, a thin film transistor disposed on the substrate, a display element electrically connected to the thin film transistor, and a sensor disposed under the substrate. The substrate includes a first substrate layer, a second substrate layer disposed on the first substrate layer, and an ultraviolet light blocking layer disposed between the first substrate layer and the second substrate layer. 
     A display device includes a substrate having a plurality of ultraviolet light blocking particles disposed therein. A thin film transistor is disposed on the substrate. A display element is electrically connected to the thin film transistor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the present disclosure and many of the attendant aspects thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
         FIGS. 1, 2, 3, 4, and 5  are cross-sectional views illustrating a display device according to exemplary embodiments of the present disclosure; and 
         FIGS. 6, 7, 8, 9, and 10  are cross-sectional views illustrating a display device according to exemplary embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     In describing exemplary embodiments of the present disclosure illustrated in the drawings, specific terminology is employed for sake of clarity. However, the present disclosure is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents which operate in a similar manner. 
     Hereinafter, a display device according to exemplary embodiments of the present disclosure will be described with reference to  FIGS. 1, 2, 3, 4, and 5 . 
       FIGS. 1, 2, 3, 4, and 5  are cross-sectional views illustrating a display device according to exemplary embodiments of the present disclosure. 
     Referring to  FIGS. 1, 2, 3, and 4 , a display device  100 , according to exemplary embodiments of the present disclosure, may include a substrate SUB, a pixel circuit disposed on the substrate SUB, and a display element DE disposed on the pixel circuit. The pixel circuit may include a thin film transistor TFT and a capacitor CAP. The display device  100  may further include a protective film  140  disposed under the substrate SUB. 
     The substrate SUB may include a first substrate layer  111 , a first barrier layer  112 , a second substrate layer  113 , a second barrier layer  114 , and a first ultraviolet light blocking layer  115 . 
     The first substrate layer  111  may include a flexible material that is also electrically insulating. For example, the first substrate layer  111  may include an organic material such as polyimide (PI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyarylate (PAR), polycarbonate (PC), polyetherimide (PEI), polyethersulfone (PS), or the like. However, the material of the first substrate layer  111  is not limited thereto, and any material that is relatively flexible and electrically insulating may be used as the material of the first substrate layer  111 . 
     The first barrier layer  112  may be disposed on the first substrate layer  111 . The first barrier layer  112  may include an inorganic material. For example, the first barrier layer  112  may include a silicon-based material such as amorphous silicon (a-Si), silicon oxide (SiO x ), silicon nitride (SiN x ), or the like. The first barrier layer  112  may be formed on the first substrate layer  111  that is vulnerable to oxygen and moisture. Accordingly, the first barrier layer  112  is configured to protect the first substrate layer  111  from damage and is configured to prevent impurities such as oxygen and moisture from permeating into the sensitive layers of the display device  100 . 
     The second substrate layer  113  may be disposed on the first barrier layer  112 . The second substrate layer  113  may include a flexible material that is electrically insulating. The second substrate layer  113  may include a material substantially the same as that of the first substrate layer  111 , or may have a thickness substantially the same as that of the first substrate layer  111 . However, the present invention is not limited thereto, and the first substrate layer  111  and the second substrate layer  113  may include different materials, or may have different thicknesses from each other. 
     The second barrier layer  114  may be disposed on the second substrate layer  113 . The second barrier layer  114  may include an inorganic material. The second barrier layer  114  may include a material substantially the same as that of the first barrier layer  112 , or may have a thickness substantially the same as that of the first barrier layer  112 . However, the present invention is not limited thereto, and the first barrier layer  112  and the second barrier layer  114  may include different materials, or may have different thicknesses from each other. The second barrier layer  114  may be formed on the second substrate layer  113  that is vulnerable to oxygen and moisture thereby protecting the second substrate layer  113  from damage and preventing impurities such as oxygen and moisture from permeating into the display device  100 . 
     The first ultraviolet light blocking layer  115  may be disposed between the first substrate layer  111  and the second substrate layer  113 . 
     The display device  100  may be exposed to ultraviolet light that is cast upon a bottom of the substrate SUB. Here, the ultraviolet light may be from sunlight, or may be ultraviolet light used during a process of manufacturing the display device  100 . For example, ultraviolet light may be used during the process of manufacturing the display device  10  to cure members formed under the substrate SUB. 
     The ultraviolet light cast onto the bottom of the substrate SUB may adversely affect the thin film transistor TFT, the capacitor CAP, and/or the display element DE. The first ultraviolet light blocking layer  115  may be formed in the substrate SUB thereby blocking the ultraviolet light from traveling to the bottom of the substrate SUB. Accordingly, damage of the thin film transistor TFT, the capacitor CAP, and the display element DE disposed over the substrate SUB may be prevented. 
     The first ultraviolet light blocking layer  115  may include a material absorbing ultraviolet light. 
     In an exemplary embodiment of the present disclosure, the first ultraviolet light blocking layer  115  may include an organic material such as a benzophenone compound, a benzotriazole compound, a benzoate compound, a cyanoacrylate compound, a triazine compound, an oxanilide compound, and/or a salicylate compound. 
     Examples of the benzophenone compound may include, for example, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-2-dihydroxybenzophenone, 2,2′,4′,4′-tetrahydroxybenzophenone, 2-hydroxy-4-octylbenzophenone. 4-dodecyloxy-2′-hydroxy-4,4′-dimethoxybenzophenone, and the like. 
     Examples of the benzotriazole compound may include 2-(5-methyl-2-hydroxyphenyl)benzotriazole, 2-(2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole, 2-(3,5-di-t-butyl-2-hydroxyphenyl)benzotriazole, 2-(3-t-butyl-5-methyl-2-hydroxyphenyl)-5-chlorobenzotriazole, 2-(3,5-di-t-butyl-2-hydroxyphenyl)-5-chlorobenzotriazole, 2-(3,5-di-t-acyl-2-hydroxyphenyl)benzotriazole, 2-(2′-hydroxy-5′-t-octylphenyl)benzotriazole, and the like. 
     Examples of the benzoate compound may include 2,4-di-t-butylphenyl-3′,5′-di-t-butyl-4-hydroxybenzoate and the like. 
     Examples of the triazine compound may include 2-[4-[(2-hydroxy-3-dodecyloxypropyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, and the like. 
     Examples of the salicylate compound may include phenyl salicylate, 4-t-butylphenylsalicylate, etc. 
     Chemical formulas of the benzophenone compound and the benzotriazole compound from among the above-stated ultraviolet light absorbent organic materials are shown below. 
     
       
         
         
             
             
         
       
     
     In Formula 1 above, R 1  may be hydrogen (H), an alkyl group, or a hydroxyl group, R 2  may be hydrogen (H), an alkyl group, or a phenyl group, R 3  may be hydrogen (H) or an alkyl group, and R 4  may be hydrogen (H) or an alkoxy group. 
     
       
         
         
             
             
         
       
     
     In Formula 2 above, R 5  may be hydrogen (H) or an alkyl group. 
     In Formulas 1 and 2, each of the benzophenone compound and the benzotriazole compound has a hydroxyl group (—OH). The first ultraviolet light blocking layer  115  may include, for example, a monomer material having a hydroxyl group (—OH), which may provide hydrogen bonding. Ultraviolet light from outside may be absorbed, for example, due to an excited-state intramolecular proton transfer (ESIPT) phenomenon. For example, the first ultraviolet light blocking layer  115  may include a compound having atoms adjacent to a hydroxyl group (—OH) and having non-covalent electron pairs, such as oxygen (O) atoms or nitrogen (N) atoms, where hydrogen bonding may be generated between a hydroxyl group (—OH) and the atoms having non-covalent electron pairs. The compound in the ultraviolet light blocking layer  115  excited by absorbing ultraviolet light may undergo phototautomerization, in which protons move in excited molecules, and thus hydrogen (H) atoms may be released from the hydroxyl group (—OH) to form a stable keto-form molecules. As a result, heat may be released. Therefore, ultraviolet light incident onto the first ultraviolet light blocking layer  115  may be converted into heat energy and radiated to the outside, which may reduce or prevent ultraviolet light from being transmitted into the display device  100 . 
     According to an exemplary embodiment of the present disclosure, the first ultraviolet light blocking layer  115  may include an inorganic material such as calcium oxide (CaO) and/or lithium fluorine (LiF). For example, when supplying oxygen on calcium after depositing the calcium, a layer on which the calcium is deposited may react with the oxygen to turn into calcium oxide (CaO), and the first ultraviolet light blocking layer  115  including calcium oxide (CaO) may be formed. Alternatively, the first ultraviolet light blocking layer  115  may be formed by exposing deposited calcium to ultraviolet light in an oxygen atmosphere. 
     In an exemplary embodiment of the present disclosure, the first ultraviolet light blocking layer  115  may be disposed between the first substrate layer  111  and the first barrier layer  112  as illustrated in  FIG. 1 , or may be disposed between the first barrier layer  112  and the second substrate layer  113  as illustrated in  FIG. 2 . The substrate SUB may include single ultraviolet light blocking layer disposed between the first substrate layer  111  and the second substrate layer  113 . 
     In an exemplary embodiment of the present disclosure, the substrate SUB may further include a second ultraviolet light blocking layer  116  as illustrated in  FIG. 3 . The second ultraviolet light blocking layer  116  may be disposed between the first substrate layer  111  and the second substrate layer  113 . The second ultraviolet light blocking layer  116  may be formed in the substrate SUB thereby blocking the ultraviolet light that is cast onto the bottom of the substrate SUB. Accordingly, damage of the thin film transistor TFT, the capacitor CAP, and the display element DE disposed over the substrate SUB may be prevented. 
     The second ultraviolet blocking layer  116  may include a material substantially the same as that of the first ultraviolet blocking layer  115 , or may have a thickness substantially the same as that of the first ultraviolet blocking layer  115 . However, the present invention is not limited thereto, and the first ultraviolet blocking layer  115  and the second ultraviolet blocking layer  116  may include different materials, or may have different thicknesses from each other. 
     The first ultraviolet blocking layer  115  may be disposed between the first substrate layer  111  and the first barrier layer  112 , and the second ultraviolet blocking layer  116  may be disposed between the first barrier layer  112  and the second substrate layer  113 . The substrate SUB may include double ultraviolet light blocking layers disposed between the first substrate layer  111  and the second substrate layer  113 . 
     In an exemplary embodiment of the present disclosure, the first ultraviolet light blocking layer  115  may be disposed between the first substrate layer  111  and the second substrate layer  113  instead of the first barrier layer  112  as illustrated in  FIG. 4 . For example, the substrate SUB might not include the first barrier layer  112 , and may instead include the first ultraviolet light blocking layer  115 . The first ultraviolet light blocking layer  115  may act as the first barrier layer  112 . 
     The first ultraviolet light blocking layer  115  may include an inorganic material such as calcium oxide (CaO) and/or lithium fluorine (LiF) among the aforementioned organic material and inorganic material. Accordingly, the first ultraviolet light blocking layer  115  may block ultraviolet light, and may prevent impurities such as oxygen and moisture from permeating into the display device  100 . 
     A buffer layer  121  may be disposed on the substrate SUB. The buffer layer  121  may prevent impurities from permeating through the substrate SUB. Further, the buffer layer  121  may planarize the surface of the substrate SUB. Alternatively, the buffer layer  121  may be omitted. 
     The thin film transistor TFT and the capacitor CAP may be disposed on the buffer layer  121 . The thin film transistor TFT may supply voltage or current to the display element DE. The display device  100  may include a thin film transistor with a top-gate structure, however, the present invention is not limited thereto. The display device  100  may include a thin film transistor with a bottom-gate structure. The thin film transistor TFT may include a first active pattern  122   a , a gate electrode  124   a , a source electrode  128   a , and a drain electrode  128   b . The capacitor CAP may maintain a voltage of the thin film transistor TFT. The capacitor CAP may include a lower electrode  124   b  and an upper electrode  126 . 
     A semiconductor layer  122   a  and  122   b  may be disposed on the buffer layer  121 . The semiconductor layer  122   a  and  122   b  may include the first active pattern  122   a  and a second active pattern  122   b . The first active pattern  122   a  and the second active pattern  122   b  may be spaced apart from each other. The semiconductor layer  122   a  and  122   b  may include amorphous silicon, polycrystalline silicon, or the like. Alternatively, the semiconductor layer  122   a  and  122   b  may include an oxide semiconductor. 
     A first insulation layer  123  may be disposed on the semiconductor layer  122   a  and  122   b . The first insulation layer  123  may insulate the gate electrode  124   a  from the first active pattern  122   a , and may insulate the lower electrode  124   b  from the second active pattern  122   b . The first insulation layer  123  may include silicon nitride (SiN x ), silicon oxide (SiO x ), or the like. 
     A first conductive layer may be disposed on the first insulation layer  123 . The first conductive layer may include the gate electrode  124   a  and the lower electrode  124   b . The gate electrode  124   a  may at least partially overlap the first active pattern  122   a . The lower electrode  124   b  may be spaced apart from the gate electrode  124   a , and may at least partially overlap the second active pattern  122   b . A thin film transistor including the second active pattern  122   b  and the lower electrode  124   b  acting as a gate may be defined. The first conductive layer may include gold (Au), silver (Ag), copper (Cu), nickel (Ni), platinum (Pt), palladium (Pd), aluminum (Al), molybdenum (Mo), and/or titanium (Ti). 
     A second insulation layer  125  may be disposed on the first conductive layer. The second insulation layer  125  may insulate the upper electrode  126  from the lower electrode  124   b . The second insulation layer  125  may include silicon nitride (SiN x ), silicon oxide (SiO x ), or the like. 
     A second conductive layer may be disposed on the second insulation layer  125 . The second conductive layer may include the upper electrode  126 . The upper electrode  126  may at least partially overlap the lower electrode  124   b . The second conductive layer may include Au, Ag, Cu, Ni, Pt, Pd, Al, Mo, and/or Ti. 
     A third insulation layer  127  may be disposed on the second conductive layer. The second insulation layer  125  and the third insulation layer  127  may together insulate both the source electrode  128   a  and the drain electrode  128   b  from the gate electrode  124   a . The third insulation layer  127  may include silicon nitride (SiN x ), silicon oxide (SiO x ), or the like. 
     A third conductive layer may be disposed on the third insulation layer  127 . The third conductive layer may include the source electrode  128   a  and the drain electrode  128   b . The source electrode  128   a  and the drain electrode  128   b  may be in contact with the first active pattern  122   a . For example, the source electrode  128   a  and the drain electrode  128   b  may be in contact with the first active pattern  122   a  through respective contact holes formed in the first insulation layer  123 , the second insulation layer  125 , and the third insulation layer  127 . The third conductive layer may include Au, Ag, Cu, Ni, Pt, Pd, Al, Mo, and/or Ti. For example, the third conductive layer may be formed as a multi-layered structure such as Mo/Al/Mo or Ti/Al/Ti. 
     A planarization layer  129  may be disposed on the third conductive layer. The planarization layer  129  may provide a planarized surface over the third conductive layer. The planarization layer  129  may include an organic material such as photoresist, polyacrylate-based resin, polyimide-based resin, siloxane-based resin, acryl-based resin, epoxy-based resin, or the like. 
     The display element DE may be disposed on the planarization layer  129 . The display element DE may be configured to emit light based on voltage or current supplied from the thin film transistor TFT. In an exemplary embodiment of the present disclosure, the display element DE may be an organic light emitting element, and may include a first electrode  131 , an organic light emitting layer  133 , and a second electrode  134 . However, the display element DE is not limited thereto, and various display elements such as a liquid crystal display element, or the like may be used as the display element DE. 
     The first electrode  131  may be disposed on the planarization layer  129 . The first electrode  131  may be patterned for each pixel of the display device  100 . The first electrode  131  may be in contact with the drain electrode  128   b . For example, the first electrode  131  may be in contact with the drain electrode  128   b  through a contact hole formed in the planarization layer  129 . The first electrode  131  may be a reflective electrode. The first electrode  131  may include a reflective layer formed of silver (Ag), magnesium (Mg), aluminum (Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Jr), chromium (Cr), or the like and a transmitting layer formed of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium oxide (In 2 O 3 ), or the like. For example, the first electrode  131  may be formed as a multi-layer structure such as ITO/Ag/ITO. 
     A pixel defining layer  132  may be disposed on the planarization layer  129  around the first electrode  131 . The pixel defining layer  132  may cover an edge of the first electrode  131 , and may include an opening that exposes a center of the first electrode  131 . The pixel defining layer  132  may include an organic material such as photoresist, polyacrylate-based resin, polyimide-based resin, siloxane-based resin, acryl-based resin, epoxy-based resin, or the like. 
     The organic light emitting layer  133  may be disposed on the first electrode  131 . The organic light emitting layer  133  may be disposed in the opening of the pixel defining layer  132 . 
     The organic light emitting layer  133  may be formed of a low molecular organic material or a high molecular organic material. When the organic light emitting layer  133  is formed of the low molecular organic material, a hole injection layer (HIL) and a hole transport layer (HTL) may be formed between the first electrode  131  and the organic light emitting layer  133 , and an electron transport layer (ETL) and an electron injection layer (EIL) may be formed on the organic light emitting layer  133 . When the organic light emitting layer  133  is formed of the high molecular organic material, the HTL may be formed between the first electrode  131  and the organic light emitting layer  133 . 
     The second electrode  134  may be disposed on the organic light emitting layer  133 . The second electrode  134  may be commonly provided to the pixels. The second electrode  134  may be a transmitting electrode. For example, the second electrode  134  may be formed of metal, metal alloy, metallic nitride, transparent metallic oxide, transparent conductive material, or the like. 
     A thin film encapsulation layer encapsulating the display element DE may be formed on the second electrode  134 . The thin film encapsulation layer may include at least one organic layer and at least one inorganic layer. 
     The organic layer may include a polymer, and may be a single layer or a stacked layer including, for example, one of polyethylene terephthalate, polyimide, polycarbonate, epoxy, polyethylene, and polyacrylate. In an embodiment, the organic layers may include polyacrylate. Specifically, the organic layer may include a polymerized monomer composition including diacrylate-based monomer and triacrylate-based monomer. The monomer composition may further include monoacrylate-based monomer. Also, the monomer composition may further include a well-known photoinitiator such as trimethyl benzoyl diphenyl phosphine oxide (“TPO”), however, the present invention is not limited thereto. 
     The inorganic layer may be a single layer or a stacked layer including metal oxide or metal nitride. In an embodiment, the inorganic layers may include one of SiN x , Al 2 O 3 , SiO 2 , and TiO 2 . 
     The protective film  140  may be disposed under the substrate SUB. The protective film  140  may absorb impact from outside thereby preventing the display device  100  from being damaged by the impact. The protective film  140  may be formed of a material containing air such as cushion, sponge, or the like to absorb impact. For example, the protective film  140  may include polyethylene terephthalate (PET) or the like. An adhesive layer may be formed between the substrate SUB and the protective film  140  and may attach the protective film  140  to the substrate SUB. 
     Referring to  FIG. 5 , the display device  100 , according to an embodiment of the present disclosure, may further include a sensor  151  disposed under the substrate SUB. For example, the sensor  151  may be disposed under the substrate SUB with the protective film  140  disposed in between. 
     In an exemplary embodiment of the present disclosure, the sensor  151  may be a fingerprint recognition sensor configured to sense a fingerprint of a user. The sensor  151  may be disposed in a display region on which the display element DE is located. 
     The sensor  151  may be attached to a bottom of the protective film  140  via an adhesive layer  152 . Ultraviolet light may be cast to a bottom of the substrate SUB to harden the adhesive layer  152 . If the ultraviolet light passes through the substrate SUB, the thin film transistor TFT, the capacitor CAP, or display element DE may be adversely affected. Further, when the ultraviolet light is cast onto the substrate SUB, a stain may be generated on the display device  100  due to the ultraviolet light. 
     To solve the aforementioned problem, the substrate SUB may include an ultraviolet light blocking layer  115  that at least partially overlaps the sensor  151  in a plan view. In an exemplary embodiment of the present disclosure, the ultraviolet light blocking layer  115  may be patterned such that at least a portion of the ultraviolet light blocking layer  115  overlaps the sensor  151 . A width of the ultraviolet light blocking layer  115  may be greater than or substantially the same as a width of the sensor  151 . 
     A cushion layer  153 , an embossing layer  154 , and a light shielding layer  155  may be disposed on a portion of the bottom of the protective layer  140  on which the sensor  151  is not disposed. 
     The cushion layer  153  may be disposed under the substrate SUB, and may reduce impact that may otherwise be applied to the display device  100 . The cushion layer  153  may include polymer such as polypropylene (PP) or polyethylene (PE). In an exemplary embodiment of the present disclosure, the cushion layer  153  may include any material that has a density of about 0.5 g/cm 3  or more. The cushion layer  153  may be formed as a foam or gel. In an exemplary embodiment of the present disclosure, the cushion layer  153  may include a material having high elastic force, for example, rubber. 
     The embossing layer  154  may be disposed between the substrate SUB and the cushion layer  153 . The embossing layer  154  may be adhesive. The embossing layer  154  may include polyethylene terephthalate (PET) or the like. 
     The shielding layer  155  may be configured to prevent elements disposed under the substrate SUB from being viewed. The shielding layer  155  may be disposed between the substrate SUB and the embossing layer  154 . The shielding layer  155  may be formed of polyethylene terephthalate (PET) or the like by a screen printing process or the like. Hereinafter, a display device according to some exemplary embodiments of the present disclosure will be described with reference to  FIGS. 6, 7, 8, 9, and 10 . 
       FIGS. 6, 7, 8, 9, and 10  are cross-sectional views illustrating a display device according to some exemplary embodiments of the present disclosure. 
     Referring to  FIGS. 6, 7, 8, 9, and 10 , a display device  200 , according to some exemplary embodiments of the present disclosure may include a substrate SUB, a pixel circuit disposed on the substrate SUB, and a display element DE disposed on the pixel circuit. The pixel circuit may include a thin film transistor TFT and a capacitor CAP. The display device  200  may further include a protective film  240  disposed under the substrate SUB. 
     In describing various elements of the display device  200  with reference to  FIGS. 6, 7, 8, 9, and 10 , some elements may be substantially the same as or similar to corresponding elements of the display device  100  described with reference to  FIGS. 1, 2, 3, 4, and 5 . To the extent that a detailed description of elements is omitted, it may be assumed that these elements are at least similar to the corresponding elements that have already been described. 
     Referring to  FIGS. 6, 7, and 8 , the substrate SUB may include a first substrate layer  211 , a first barrier layer  212 , a second substrate layer  213 , and a second barrier layer  214 . 
     The first substrate layer  211  and/or the second substrate layer  213  may include a matrix including an organic material and a plurality of ultraviolet light blocking particles dispersed within the matrix. 
     The ultraviolet light blocking particles may include an organic material such as a benzophenone compound, a benzotriazole compound, a benzoate compound, a cyanoacrylate compound, a triazine compound, an oxanilide compound, and/or a salicylate compound. 
     An amount of the ultraviolet light blocking particles in the matrix may vary, for example, depending on the thickness of the first and/or second substrate layers  211  and/or  213 , the absorption wavelength range of the ultraviolet light blocking particles, or the like. For example, the ultraviolet light blocking particles may be included in an amount of about 0.1 wt % to about 20 wt %. 
     The matrix may include an organic material based on which the film characteristics of the first and/or second substrate layers  211  and/or  213 , and may include, for example, an organic material such as polyimide (PI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyarylate (PAR), polycarbonate (PC), polyetherimide (PEI), polyethersulfone (PS), or the like. 
     Various methods may be used to form the first and/or second substrate layers  211  and/or  213 . For example, an organic film forming layer, including, for example, a mixture of a first monomer including an organic material for forming the matrix and a second monomer including the ultraviolet light blocking particles, may be accommodated on a carrier substrate by using methods, such as evaporation, inkjet printing, screen printing, and spin coating. 
     In an exemplary embodiment of the present disclosure, the ultraviolet light blocking particles may be cross-linked within the matrix. 
     The ultraviolet light blocking particles may include, for example, an acrylate group, a methacrylate group, and/or an epoxy group, and may have a structure in which the material or compound is coupled with at least one functional group from among an acrylate group, a methacrylate group, and an epoxy group. The functional group may be cross-linked within the matrix, which may provide a more dense film characteristic to the first and/or second substrate layers  211  and/or  213 . 
     Referring to  FIG. 6 , in an exemplary embodiment of the present disclosure, the first substrate layer  211  may include a first matrix  211   b  including an organic material and a plurality of first ultraviolet light blocking particles  211   a  dispersed in the first matrix  211   b , and the second substrate layer  213  might not include the ultraviolet light blocking particles. The first substrate layer  211  may block ultraviolet light cast to a bottom of the display device  200 . 
     Referring to  FIG. 7 , in another embodiment, the second substrate layer  213  may include a second matrix  213   b  including an organic material and a plurality of second ultraviolet light blocking particles  213   a  dispersed in the second matrix  213   b , and the first substrate layer  211  might not include the ultraviolet light blocking particles. The second substrate layer  213  may block ultraviolet light cast to the bottom of the display device  200 . 
     Referring to  FIG. 8 , according to an exemplary embodiment of the present disclosure, the first substrate layer  211  may include a first matrix  211   b  including an organic material and a plurality of first ultraviolet light blocking particles  211   a  dispersed in the first matrix  211   b , and the second substrate layer  213  may include a second matrix  213   b  including an organic material and a plurality of second ultraviolet light blocking particles  213   a  dispersed in the second matrix  213   b . The first and second substrate layers  211  and  213  may block ultraviolet light cast to the bottom of the display device  200 . 
     Referring to  FIG. 9 , the display device  200 , according to an exemplary embodiment of the present disclosure, may further include a sensor  251  disposed under the substrate SUB. For example, the sensor  251  may be disposed under the substrate SUB with the protective film  240  disposed in between. The first substrate layer  211  may include the first ultraviolet light blocking particles  211   a  overlapping the sensor  251  in a plan view. The first ultraviolet light blocking particles  211   a  may be dispersed within the first matrix  211   b  to overlap the sensor  251 , and the first ultraviolet light blocking particles  211   a  might not be located in a portion of the first substrate layer  211  which does not overlap the sensor  251 . For example, a width of a region in which the first ultraviolet light blocking particles  211   a  are located may be greater than or substantially the same as a width of the sensor  251 . 
     Referring to  FIG. 10 , the substrate SUB of the display device  200 , according to an exemplary embodiment of the present disclosure, might not include the first substrate layer  211 , the first barrier layer  212 , the second substrate layer  213 , and the second barrier layer  214 , different from the substrate SUB of the display device  200  described above. The substrate SUB may include a plurality of ultraviolet light blocking particles SUBa dispersed therein. 
     In an exemplary embodiment of the present disclosure, the substrate SUB may include an organic material such as polyimide (PI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyarylate (PAR), polycarbonate (PC), polyetherimide (PEI), polyethersulfone (PS), or the like. In an exemplary embodiment of the present disclosure, the substrate SUB may include glass, quartz, ceramic, metal, or the like. 
     The display device, according to exemplary embodiments of the present disclosure, may be applied to a display device included in a computer, a notebook, a mobile phone, a smartphone, a smart pad, a PMP, a PDA, an MP3 player, or the like. 
     Although the display devices, according to exemplary embodiments of the present invention, have been described with reference to the drawings, the illustrated embodiments are examples, and may be modified and changed by a person having ordinary knowledge in the relevant technical field without departing from the technical spirit of the present disclosure.