Patent Publication Number: US-2018047791-A1

Title: Display device

Description:
CROSS-REFERENCE TO RELATED FIELD APPLICATION 
     This application claims the priority benefits of Taiwan application serial no. 105125896, filed on Aug. 15, 2016. The entirety of the above-mentioned patent applications is hereby incorporated by reference herein. 
     Technical Field 
     The disclosure relates to a display device. 
     Background 
     A light emitting diode display is a display element utilizing the self-luminescent characteristics of light emitting materials to display. The luminescent structure of the light emitting diode display mainly includes a pair of electrodes and a light emitting layer between the electrodes. When a current flows through the light emitting layer via an anode and a cathode, electrons and holes are combined in the light emitting layer to generate excitons, so as to generate light beams of different colors based on material characteristics of the light emitting layer. 
     For a self-luminescent display, the display quality affected by the ambient light is an important factor need to be considered. The color purity is also a factor to affect the display quality. The display quality of high output luminance, high ambient contrast ratio and good color purity are required for a self-luminescent display. 
     SUMMARY 
     An embodiment of the disclosure provides a display device including a substrate, a plurality of pixel structures and a color filter layer. The substrate has a plurality of pixel regions thereon. The plurality of pixel structures are correspondingly disposed on the plurality of pixel regions, respectively. Each of the pixel structures includes an active device layer, a light absorption layer, an optical matching layer, a first transparent electrode, a light emitting layer and a second transparent electrode. The active device layer is disposed on the substrate, the light absorption layer is disposed on the active device layer, the optical matching layer is disposed on the light absorption layer, the first transparent electrode is disposed on the optical matching layer, the light emitting layer is disposed on the first transparent electrode and the second transparent electrode is disposed on the light emitting layer. The color filter layer covers the plurality of pixel structures and has a plurality of color filter elements correspondingly disposed in the plurality of pixel regions, respectively. The plurality of pixel structures are disposed between the substrate and the color filter. 
     The foregoing will become better understood from a careful reading of a detailed description provided herein below with appropriate reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a display device according to an embodiment of the disclosure. 
         FIG. 2A  illustrates a top view of the display device of  FIG. 1 . 
         FIG. 2B  illustrates a top view of the display device of  FIG. 1  and  FIG. 7 . 
         FIG. 3A  to  FIG. 3C  illustrate a relationship between wavelength and emission intensity of a display device according to an embodiment of the disclosure. 
         FIG. 4A  to  FIG. 4C  illustrate a relationship between wavelength and reflectance of a display device according to an embodiment of the disclosure. 
         FIG. 5  illustrates a display device according to another embodiment of the disclosure. 
         FIG. 6  illustrates a top view of the display device of  FIG. 5  and  FIG. 8 . 
         FIG. 7  illustrates a display device according to another embodiment of the disclosure. 
         FIG. 8  illustrates a display device according to another embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS 
     Below, exemplary embodiments will be described in detail with reference to accompanying drawings so as to be easily realized by a person having ordinary knowledge in the art. The inventive concept may be embodied in various foiiiis without being limited to the exemplary embodiments set forth herein. Descriptions of well-known parts are omitted for clarity, and like reference numerals refer to like elements throughout. 
       FIG. 1  illustrates a display device according to an embodiment of the disclosure. As shown in  FIG. 1 , a display device  100  includes a substrate  110 , a plurality of pixel structures  120  and a color filter layer  130 . The substrate  110  has a plurality of pixel regions  111  thereon. The plurality of pixel structures  120  are correspondingly disposed on the pixel regions  111 , respectively. Each of the pixel structures  120  includes an active device layer  121 , a light absorption layer  122 , an optical matching layer  123 , a first transparent electrode  124 , a light emitting layer  125  and a second transparent electrode  126 . The active device layer  121  is disposed on the substrate  110 , the light absorption layer  122  is disposed on the active device layer  121 , the optical matching layer  123  is disposed on the light absorption layer  122 , the first transparent electrode  124  is disposed on the optical matching layer  123 , the light emitting layer  125  is disposed on the first transparent electrode  124  and the second transparent electrode  126  is disposed on the light emitting layer  125 . The color filter layer  130  covers the plurality of pixel structures  120  and has a plurality of color filter elements  131  correspondingly disposed in the plurality of pixel regions  111 , respectively. The plurality of pixel structures  120  is disposed between the substrate  110  and the color filter layer  130 . 
       FIG. 2A  illustrates a top view of the display device  100  of  FIG. 1 .  FIG. 2A  illustrates the substrate  110  and the plurality of pixel regions  111 . The substrate  110  has a plurality of pixel regions  111  thereon. In this embodiment, the plurality of pixel regions are arranged in an array on the substrate. The plurality of pixel structures  120  and the plurality of color filter elements  131  are correspondingly disposed on the pixel regions  111 , respectively.  FIG. 2A  also illustrates light emission regions Re and non-emission regions Rne of the display device  100 . Each of the light emission regions Re is located in one of the pixel regions  111 . The light emission regions Re of  FIG. 2A  are substantially located in the center of the pixel regions  111 , but it&#39;s just an exemplary embodiment, the scope of the disclosure is not limited thereto. 
     The light emission region Re in one of pixel regions  111  is defined by the first transparent electrode  124 , the light emitting layer  125  and the second transparent electrode  126  of the pixel region  111 . The light emitting layer  125  disposed between the first transparent electrode  124  and the second transparent electrode  126  may emit light by applying a voltage to the electrodes and fonn the light emission region Re. The region excluding the light emission region Re in the pixel region  111  is non-emission region Rne. 
     In the present embodiment, the substrate  110  may be, but not limited to a flexible substrate, wherein the material of the flexible substrate may be polyimide (PI), complex of polyimide and inorganic material(hybrid PI), Polyethylene terephthalate (PET), Polyethersulfone (PES), polyacrylate (PA), Polyethylene naphthalatc (PEN), polycarbonate (PC), polynorbornene (PNB), polyetherimide (PEI), polyetheretherketone (PEEK), Cyclo olefin polymer (COP), PMMA, Glass Fiber Reinforced Plastic (GFRP) or Carbon Fiber Reinforced Polymer (CFRP), or the like. In another embodiment, the substrate  110  may be made of glass or other rigid materials. Alternately, the substrate  110  may also be a composite substrate made of a plurality of material layers for providing gas or vapor barrier functions, wherein the material layers may include at least one organic layer and/or at least one inorganic layer. The scope of the disclosure is not limited thereto. 
     The active device layer  121  comprises a thin film transistor (TFT), for instance. The thin film transistor may be an organic thin film transistor (OTFT). The light absorption layer  122  may be a black resin, for example, for absorbing external ambient light. Alternatively, the light absorption layer  122  may include a multi-layer structure formed by alternately stacking different film-layers, such as a low-reflectance multi-layer structure formed by alternately stacking a plurality of LiF layers and a plurality of Cr layers. The optical matching layer  123  may include a single layer or a multi-layer structure formed by alternately stacking different film-layers, such as a multi-layer structure formed by alternately stacking a plurality of SiO 2  and TiO 2  layers. The first transparent electrode  124  and the second transparent electrode  126  may be respectively an anode and a cathode for providing a current to the light emitting layer  125 , so that the light emitting layer  125  may emit light beams L 1  and L 2 . The first transparent electrode  124  and the second transparent electrode  126  may include indium tin oxide (ITO), indium zinc oxide (IZO), etc., but the scope of the disclosure is not limited thereto. The first transparent electrode  124  and the second transparent electrode  126  may be made of the same material or different materials. The light emitting layer  125  may be any organic light emitting layer suitable for an organic light emitting diode (OLED) display device, or an inorganic light emitting layer (or a quantum dot light emitting layer) suitable for a quantum dot light emitting diode (QLED) display device, for example. The color filter elements  131  may include photosensitive resin or thermosetting resin, but the scope of the disclosure is not limited thereto. 
     The light emitting layer  125  may be formed, by sequentially stacking a first carrier injection layer, a first carrier transmission layer, a second carrier blocking layer, an emission layer, a first carrier blocking layer, a second carrier transmission layer and a second carrier injection layer, from the first transparent electrode  124  to the second transparent electrode  126 . The first carrier and the second carrier described in the embodiment may be considered as different types of carriers such as electron and hole. For example, the first carrier is an electron and the second carrier is an electric hole, or the first carrier is an electric hole and the second carrier is an electron. The scope of the disclosure is not limited thereto. In one embodiment of  FIG. 1  the light emitting layer  125  includes an emission layer  1251 , an electron transmission layer (ETL)  1252  and a hole transmission layer (HTL)  1253 , wherein the emission layer  1251  is disposed between the electron transmission layer (ETL)  1252  and the hole transmission layer (HTL)  1253 . The structure of the light emitting layer  125  is not limited to the present embodiment. 
     In another embodiment, the display device  100  further includes a pixel define layer (PDL)  140 , a thin film encapsulation (TFE) layer  150 , glue  160  and a cover  170 . The plurality of pixel structures  120  of the display device  100  are defined by the pixel define layer (PDL)  140 . The pixel define layer (PDL)  140  is disposed between the light emitting layer  125  and the light absorption layer  122 . The optical matching layer  123  and the first transparent electrode  124  are disposed between the light absorption layer  122  and the pixel define layer (PDL)  140 . The thin film encapsulation (TFE) layer  150  is disposed on the second transparent electrode  126 , the glue  160  disposed on the thin film encapsulation (TFE) layer  150 . The thin film encapsulation (TFE) layer  150  and the glue  160  are disposed between the second transparent electrode  126  and the color filter layer  130 , the cover  170  is disposed on the color filter layer  130 , and the color filter layer  130  is disposed between the glue  160  and the cover  170 . 
     In the embodiment, the color filter layer  130  is formed on the cover  170  and the pixel structures  120 , the pixel define layer (PDL)  140 , and the thin film encapsulation (TFE) layer  150  are formed on the substrate  110  in sequence during the process of fabricating the display device  100 . The color filter layer  130  on the cover  170  and the thin film encapsulation (TFE) layer  150  on the substrate  110  are bonded by the glue  160 . Then the display device  100  is completed. 
     The pixel define layer (PDL)  140  may include photosensitive resin. The thin film encapsulation (TFE) layer  150  may include a multi-layer structure formed by stacking different inorganic films, such as a multi-layer structure foamed by alternately stacking a plurality of silicon nitride (SiN x ) and silicon oxycarbide (SiOC) films. But the number of layers or the material constituting of the inorganic films is not limited to the present embodiment. In other embodiment, the thin film encapsulation layer  150  may include a single layer or a multi-layer structure formed by alternately stacking organic or inorganic films. The inorganic material includes, for instance, Al 2 O 3 , SiO x , SiN x , SiO x N y  or SiOC. The organic material includes parylene, polymer or acrylic. It may be appropriately changed according to the actual design requirement. The glue  160  may include Epoxy resin, Urea resin, Melamine, Phenol resin, Acrylics, Butyl rubber, ethylene-vinyl acetate, nitriles, silicon rubber, styrene block copolymer. The scope of the disclosure is not limited thereto. 
     The cover  170  may be, but not limited to a flexible substrate, wherein the material of the flexible substrate may be polyimide (PI), complex of polyimide and inorganic material (hybrid PI), Polyethylene terephthalate (PET), Polyethersulfone (PES), polyacrylate(PA), Polyethylene naphthalatc (PEN), polycarbonate(PC), polynorbornene (PNB), polyetherimide (PEI), polyetheretherketone (PEEK), Cyclo olefin polymer (COP), PMMA, Glass Fiber Reinforced Plastic (GFRP) or Carbon Fiber Reinforced Polymer (CFRP), or the like. In another embodiment, the cover  170  may be made of glass or other rigid material. Alternately, the cover  170  may also be a composite substrate made of a plurality of material layers for providing gas or vapor barrier functions, wherein the material layers may include at least one organic layer and/or at least one inorganic layer. The scope of the disclosure is not limited thereto. 
     In this embodiment, to prevent the light beam L 1  emitted downward from being absorbed by the light absorption layer  122 , the optical matching layer  123  is disposed between the light absorption layer  122  and the first transparent electrode  124 . In addition, with the optical matching layer  123  being matched with the light absorption layer  122 , a portion of the light beam L 1  emitted downward may be reflected by the optical matching layer  123  to maintain a top output luminance without reflecting a significant amount of the ambient light. Here, a refractive index of the light absorption layer  122  and a refractive index of the optical matching layer  123  are set to satisfy the condition of 0.008&lt;[(n 1 −n 2 )/(n 1 +n 2 )]̂2&lt;0.8, wherein n 1  is the refractive index of the light absorption layer  122 , and n 2  is a refractive index of the optical matching layer  123 . In this embodiment, the refractive index of the light absorption layer  122  is less than the refractive index of the optical matching layer  123 . Namely, in this embodiment, the top output luminance and a reflectance of the ambient light are controlled by adjusting the refractive indices of the optical matching layer  123  and the light absorption layer  122 , so as to increase an ambient contrast ratio of the display device  100 . In the present embodiment, the color purity of the display device  100  also may be increased due to the disposition of color filter elements  131 . 
     When the optical matching layer  123  includes a metal material, such as Al, Ag, or AlNd, etc., the refractive index of the light absorption layer  122  and the refractive index of the optical matching layer  123  satisfy the condition of 0.008&lt;[(n 1 −n 2 )/(n 1 +n 2 )]̂2&lt;0.8. Also, when the optical matching layer  123  includes a material such as Si, the refractive index of the light absorption layer  122  and the refractive index of the optical matching layer  123  satisfy the condition of 0.008&lt;[(n 1 −n 2 )/(n 1 +n 2 )]̂2&lt;0.3. Furthermore, when the optical matching layer  123  includes an organic material or a metal oxide, such as SiO x  or Nb 2 O x , etc., the refractive index of the light absorption layer  122  and the refractive index of the optical matching layer  123  satisfy the condition of 0.008&lt;[(n 1 −n 2 )/(n 1 +n 2 )]̂2&lt;0.15. 
     Please refer to  FIG. 1  again, in one pixel region  111 , the color of the light emitted by the light emitting layer  125  of the pixel structure  120  is substantially the same as the filtered color of the color filter element  131  (the color that appears after the white color passes through the color filter element  131 ) in the same pixel region  111 . The color of the light emitted by the light emitting layer  125  of a pixel structure  120  in one pixel region  111  may be the same as or different from the color of the light emitted by the light emitting layer  125  of its one or more neighboring the pixel structures  120 . 
       FIG. 2B  illustrates a top view of the display device  100  of  FIG. 1 .  FIG. 2B  illustrates a substrate  110 , a plurality of pixel regions  111 , light emission regions Re and non-emission regions Rne of the display device  100 . In the embodiment, the color of the light emitted by the light emitting layer  125  of the pixel structure  120  is substantially the same as the filtered color of the color filter element  131  in the same pixel region  111 . The light emitting layer  125  of the display device  100  includes a first light emitting layer (light emission region Re 1 ) for emitting light of a first color, a second light emitting layer (light emission region Re 2 ) for emitting light of a second color, and a third light emitting layer (light emission region Re 3 ) for emitting light of a third color in different pixel regions of the plurality of pixel regions  111 . The first light emitting layer, the second light emitting layer, and the third light emitting layer respectively correspond to three color filter elements, and the filtered colors of the three color filter element are respectively the same as the three colors of the light emitted by the light emitting layer  125 , as show in  FIG. 1 , the three color filter elements are a first color filter element  1311 , a second color filter element  1312 , and a third color filter element  1313 , respectively. The light emission regions Re 1 , Re 2  and Re 3  are arranged in sequence and repeatedly along a first direction D 1  shown in  FIG. 2B . The light emission regions Re 1 , Re 2  and Re 3  are arranged with the light emission regions of same light emitting color and repeatedly along a second direction D 2 , as shown in  FIG. 2B . The first direction D 1  is substantially perpendicular to the second direction D 2 . The non-emission region Rne in each pixel region  111  exhibit the filtered color of its corresponding color filter element  131  in the pixel region  111 .  FIG. 2B  illustrates the arrangement of the non-emission regions of the first color Rne 1 , the non-emission regions of the second color Rne 2  and the non-emission regions of the third color Rne 3 . In one embodiment, the first color, the second color and the third color are red, green and blue respectively. In other embodiments, the first color, the second color and the third color may be other colors, but the scope of the disclosure is not limited thereto. In addition, there are 3 kinds of pixel colors in the embodiment, but in other embodiments, the number of pixel colors may be greater or less than 3, but the scope of the disclosure is not limited thereto. 
     The arrangements of the pixels of the first color, the second color and the third color illustrated in the embodiments of  FIG. 2A  and  FIG. 2B  are strip-shaped. In other embodiments, the arrangement of the 3 pixel colors may be triangle-shaped or a mosaic arrangement, but the scope of the disclosure is not limited thereto. Pixel regions are categorized by their pixel arrangements. That is, pixel regions correspond to pixel arrangements, respectively. Color filter elements  131  also respectively correspond to the pixel arrangements. In a same pixel region, the filtered color of the color filter element  131  is substantially the same as the color of the light emitted by the light emitting layer  125 . 
       FIG. 3A  to  FIG. 3C  illustrate a relationship between wavelength and emission intensity of a display device  100  according to an embodiment of the disclosure, which illustrate the simulation results of the emission intensity of the display device  100 . Wherein  FIG. 3A  illustrates a relationship between the wavelength and the emission intensity of red light. The horizontal axis represents wavelength and the wavelength unit is nanometer. The vertical axis represents emission intensity and the unit is W·m −2 ·nm −1 ·sf −1 . The dotted line represents the relationship between wavelength and emission intensity without adding the color filter (CF) layer  130  in the embodiment. The solid line represents the relationship between wavelength and emission intensity with adding the color filter (CF) layer  130  in the embodiment. In  FIG. 3A , the filtered color of the color filter layer  130  is red. The disposition of the color filter layer  130  may narrow the full width at half maximum (FWHM) of the spectrum of output light, and raise the red color purity of the display device  100 . Similar to  FIG. 3A ,  FIG. 3B  illustrate a relationship between the wavelength and the emission intensity of green light,  FIG. 3C  illustrate a relationship between the wavelength and the emission intensity of blue light. As shown in  FIG. 3B  and  FIG. 3C , the disposition of the color filter (CF) layer  130  (In  FIG. 3B  and  FIG. 3C , the filtered colors of the color filter layer  130  are green and blue, respectively) narrow the full width at half maximum (FWHM) of the spectrum of output light, and raise the green color purity and the blue color purity of the display device  100 . Therefore, the color purity of the display device  100  may be increased. 
       FIG. 4A to 4C  illustrate a relationship between wavelength and reflectance of a display device according to an embodiment of the disclosure, which illustrate the simulation results of the reflectance of the display device  100 . The reflectance means the ratio of the ambient light incident to the display device  100  to the reflected light of the ambient light from the display device  100 .  FIG. 4A  illustrates a relationship between the wavelength and the reflectance of red light. The horizontal axis represents wavelength and the wavelength unit is nanometer. The vertical axis represents reflectance. The dotted line represents the relationship between the wavelength and the reflectance without adding the color filter layer  130  in the embodiment. The solid line represents the relationship between the wavelength and the reflectance of the display device with adding the color filter layer  130  in the embodiment. In  FIG. 4A , the filtered color of the color filter layer  130  is red. The disposition of the color filter layer  130  may reduce the reflectance of the red light and raise the ambient contrast ratio of the display device  100 . Similar to  FIG. 4A ,  FIG. 4B  illustrates a relationship between the wavelength and the reflectance of green light,  FIG. 4C  illustrates a relationship between the wavelength and the reflectance of blue light. As shown in  FIG. 4B  and  FIG. 4C , the disposition of the color filter layer  130  (In  FIG. 4B  and  FIG. 4C , the filtered colors of the color filter layer  130  are green and blue, respectively) reduces the reflectance of the green light and the blue light. Therefore, the ambient contrast ratio of the display device  100  may be raised. 
       FIG. 5  illustrates a display device according to another embodiment of the disclosure. As shown in  FIG. 5 , a display device  500  is similar to the display device  100  in the previous embodiment. The same or similar reference numbers used in each of the following exemplary embodiments represent the same or the like elements, and thus descriptions of the same or the like elements will not be repeatedly provided hereinafter. The difference between the two display devices is that the color filter layer  130  of the display device  500  further includes a plurality of black matrix (BM) structures  532 , in addition to the plurality of color filter element  531 . As shown in  FIG. 5 , the display device  500  includes the substrate  110 , the plurality of pixel structures  120  and the color filter layer  530 . The substrate  110  has a plurality of pixel regions  111  thereon. The plurality of pixel structures  120  are correspondingly disposed on the pixel regions  111 , respectively. Each of the pixel structures  120  includes the active device layer  121 , the light absorption layer  122 , the optical matching layer  123 , the first transparent electrode  124 , the light emitting layer  125  and the second transparent electrode  126 . The active device layer  121  is disposed on the substrate  110 , the light absorption layer  122  is disposed on the active device layer  121 , the optical matching layer  123  is disposed on the light absorption layer  122 , the first transparent electrode  124  is disposed on the optical matching layer  123 , the light emitting layer  125  is disposed on the first transparent electrode  124  and the second transparent electrode  126  is disposed on the light emitting layer  125 . The color filter layer  530  covers the plurality of pixel structures  120  and has a plurality of color filter elements  531  and a plurality of black matrix (BM) structures  532 . The plurality of color filter elements  531  are correspondingly disposed in the plurality of pixel regions  111 , respectively. The disposition of the black matrix (BM) structures  532  may further reduce the reflectance of the ambient light incident to the display device and increase the ambient contrast ratio. 
       FIG. 2A  also illustrates a top view of the display device  500  of  FIG. 5 .  FIG. 2A  illustrates the substrate  110  and the plurality of pixel regions  111 . The substrate  110  has a plurality of pixel regions  111  thereon. The pixel regions are arranged in an array on the substrate, and comprises light emission regions Re and non-emission regions Rne. The light emission regions are located in the pixel regions. The regions excluding the light emission regions Re in the pixel regions  111  are non-emission regions Rne. As shown in  FIG. 5 , each of the color filter elements  531  is correspondingly disposed in one of the light emission regions Re of a same pixel region, while each of the black matrix (BM) structures  532  is correspondingly disposed in one of the non-emission regions Rne of the same pixel region. The light emission region Re of  FIG. 2A  is substantially located at the center of the pixel region  111 , but it&#39;s only an exemplary embodiment, the scope of the disclosure is not limited thereto. The light emission region Re may be located at any position in the pixel region. 
     The light emission region Re in one pixel region  111  is defined by the first transparent electrode  124 , the light emitting layer  125  and the second transparent electrode  126  in the pixel region. The light emitting layer  125  disposed between the first transparent electrode  124  and the second transparent electrode  126  may emit light and form the light emission region Re. In each pixel region  111 , the region excluding the light emission region Re is a non-emission region Rne. 
     In the pixel regions  111 , the shape or the size of the color filter elements  131  may be designed according to the actual demands. The color filter elements  531  in each pixel region  111  substantially cover all the lighting area of the light emission region Re in the pixel region  111 . The region excluding the color filter elements in the color filter layer  530  of each pixel region  111  is the black matrix (BM) structure  532 . 
     In the present embodiment, the substrate  110  may be, but not limited to a flexible substrate, wherein the material of the flexible substrate may be polyimide (PI), complex of polyimide and inorganic material(hybrid PI), Polyethylene terephthalate (PET), Polyethersulfone (PES), polyacrylate (PA), Polyethylene naphthalatc (PEN), polycarbonate (PC), polynorbornene (PNB), polyetherimide (PEI), polyetheretherketone (PEEK), Cyclo olefin polymer (COP), PMMA, Glass Fiber Reinforced Plastic (GFRP) or Carbon Fiber Reinforced Polymer (CFRP), or the like. In another embodiment, the substrate  110  may be made of glass or other rigid material. Alternately, the substrate  110  may also be a composite substrate made of a plurality of material layers for providing gas or vapor barrier functions, wherein the material layers may include at least one organic layer and/or at least one inorganic layer. The scope of the disclosure is not limited on the type and the composition of the substrate  110 . 
     The active device layer  121  comprises a thin film transistor (TFT), for instance. The thin film transistor may be organic thin film transistor (OTFT). The light absorption layer  122  is a black resin, for example, for absorbing external ambient light. Alternatively, the light absorption layer  122  may include a multi-layer structure formed by alternately stacking different layers, such as a low reflectance multi-layer structure formed by alternately stacking a plurality of LiF layers and a plurality of Cr layers. The optical matching layer  123  may include a single layer or a multi-layer structure foiiiied by alternately stacking different films, such as a multi-layer structure formed by alternately stacking a plurality of SiO 2  and TiO 2  layers. The first transparent electrode  124  and the second transparent electrode  126  may be respectively an anode and a cathode that provide a current to the light emitting layer  125 , so that the light emitting layer  125  may emit light beams LI and L 2 . The first transparent electrode  124  and the second transparent electrode  126  may include indium tin oxide (ITO), indium zinc oxide (IZO), etc. The disclosure is not limited thereto. The first transparent electrode  124  and the second transparent electrode  126  may be made of the same material or different materials. The light emitting layer  125  may be any organic light emitting layer suitable for an organic light emitting diode (OLED) display device, or an inorganic light emitting layer (or a quantum dot light emitting layer) suitable for a quantum dot light emitting diode (QLED) display device, for example. The color filter elements  131  may include photosensitive resin or thermosetting resin, but the scope of the disclosure is not limited thereto. 
     The light emitting layer  125  is formed by sequentially stacking a first carrier injection layer , a first carrier transmission layer, a second carrier blocking layer, an emission layer, a first carrier blocking layer, a second carrier transmission layer and a second carrier injection layer from the first transparent electrode  124  to the second transparent electrode  126 . The first carrier and the second carrier described in the embodiment may be considered as different types of carriers such as the first carrier is an electron and the second carrier is an electric hole, or the first carrier is an electric hole and the second carrier is an electron. The scope of the disclosure is not limited thereto, which may be adjustable according to demands. In one embodiment of  FIG. 5 , the light emitting layer  125  includes an emission layer  1251 , an electron transmission layer (ETL)  1252  and a hole transmission layer (HTL)  1253 , wherein the emission layer  1251  is disposed between the electron transmission layer (ETL)  1252  and the hole transmission layer (HTL)  1253 . The present composition of the light emitting layer  125  is not limited in the embodiments of the disclosure. 
     In another embodiment, the display device  500  further includes a pixel define layer (PDL)  140 , a thin film encapsulation (TFE) layer  150 , glue  160  and a cover  170 . The plurality of pixel structures  120  of the display device  500  are defined by the pixel define layer (PDL)  140 . The pixel define layer (PDL)  140  is disposed between the light emitting layer  125  and the light absorption layer  122 . The optical matching layer  123  and the first transparent electrode  124  are disposed between the light absorption layer  122  and the pixel define layer (PDL)  140 . The thin film encapsulation (TFE) layer  150  is disposed on the second transparent electrode  126 , and the glue  160  is disposed on the thin film encapsulation (TFE) layer  150 . The thin film encapsulation (TFE) layer  150  and the glue  160  are disposed between the second transparent electrode  126  and the color filter layer  530 , the cover  170  is disposed on the color filter layer  530 , and the color filter layer  530  is disposed between the glue  160  and the cover  170 . 
     The pixel define layer (PDL)  140  may include photosensitive resin. The thin film encapsulation (TFE) layer  150  may include a multi-layer structure formed by stacking different inorganic films, such as a multi-layer structure formed by alternately stacking a plurality of silicon nitride (SiN x ) and silicon oxycarbide (SiOC) films. But the number of layers or the material constituting of the inorganic films is not limited in the present embodiment. In other embodiments, the thin film encapsulation layer  150  may include a single layer or a multi-layer structure formed by alternately stacking organic or inorganic films. The inorganic material includes, for instance, Al 2 O 3 , SiO x , SiN X , SiO X N y  or SiOC. The organic material includes parylene, polymer or acrylic. It may be appropriately changed according to the actual design requirement. The glue  160  may include Epoxy resin, Urea resin, Melamine, Phenol resin, Acrylics, Butyl rubber, ethylene-vinyl acetate, nitriles, silicon rubber, styrene block copolymer. The scope of the disclosure is not limited thereto. 
     The cover  170  may be, but not limited to a flexible substrate, wherein the material of the flexible substrate may be polyimide(PI), complex of polyimide and inorganic material(hybrid PI), Polyethylene terephthalate (PET), Polyethersulfone (PES), polyacrylate (PA), Polyethylene naphthalatc (PEN), polycarbonate (PC), polynorbornene (PNB), polyetherimide (PEI), polyetheretherketone (PEEK), Cyclo olefin polymer (COP), PMMA, Glass Fiber Reinforced Plastic(GFRP) or Carbon Fiber Reinforced Polymer(CFRP), or the like. In another embodiment, the cover  170  may be made of glass or other rigid material. Alternately, the cover  170  may also be a composite substrate made of a plurality of material layers for providing gas/vapor barrier functions, wherein the material layers may include at least one organic layer and/or at least one inorganic layer. The scope of the disclosure is not limited thereto. 
     In this embodiment, to prevent the light beam L 1  emitted downward from being absorbed by the light absorption layer  122 , the optical matching layer  123  is disposed between the light absorption layer  122  and the first transparent electrode  124 . In addition, with the optical matching layer  123  being matched with the light absorption layer  122 , a portion of the light beam L 1  emitted downward may be reflected by the optical matching layer  123  to maintain an upward output luminance without reflecting a significant amount of the ambient light. Here, a refractive index of the light absorption layer  122  and a refractive index of the optical matching layer  123  are set to satisfy the condition of 0.008&lt;[(n 1 −n 2 )/(n 1 +n 2 )]̂2&lt;0.8, wherein n 1  is the refractive index of the light absorption layer  122 , and n 2  is a refractive index of the optical matching layer  123 . In this embodiment, the refractive index of the light absorption layer  122  is less than the refractive index of the optical matching layer  123 . In other words, in this embodiment, the upward top output luminance and a reflectance of the ambient light are controlled by adjusting the refractive indices of the optical matching layer  123  and the light absorption layer  122 , so as to raise an ambient contrast ratio of the display device  500 . In the present embodiment, the color purity of the display device  500  also may be raised due to the disposition of the color filter elements  531 . 
     When the optical matching layer  123  includes a metal material, such as Al, Ag, or AlNd, etc., the refractive index of the light absorption layer  122  and the refractive index of the optical matching layer  123  satisfy the condition of 0.008&lt;[(n 1 −n 2 )/(n 1 +n 2 )]̂2&lt;0.8. Also, when the optical matching layer  123  includes a material such as Si, the refractive index of the light absorption layer  122  and the refractive index of the light matching layer  123  satisfy the condition of 0.008&lt;[(n 1 −n 2 )/(n 1 +n 2 )]̂2&lt;0.3. Furtheimore, when the optical matching layer  123  includes an organic material or a metal oxide, such as SiO x  or Nb 2 O x , etc., the refractive index of the light absorption layer  122  and the refractive index of the optical matching layer  123  satisfy the condition of 0.008&lt;[(n 1 −n 2 )/(n 1 +n 2 )]̂2&lt;0.15. 
     Please refer to  FIG. 5  again, in an exemplary embodiment, the color of the light emitted by the light emitting layer  125  of each pixel structure  120  in the plurality of pixel regions  111  is substantially the same as the filtered color of the color filter element  531 (the color that appears after the white color passes through the color filter element  531 ) corresponding to the same pixel region  111 . The color of the light emitted by the light emitting layer  125  of one pixel structure  120  in one pixel region  111  may be the same as or different from the color of the light emitted by the light emitting layer  125  of the pixel structure  120  in one or more neighboring pixel regions  111 . 
     In the pixel regions  111 , the shape or the size of the color filter elements  531  may be designed according to the actual demands. The color filter elements  531  in each pixel region  111  substantially cover all the lighting areas of the light emission region Re. In each pixel region  111 , the area excluding the color filter elements  531  is a black matrix (BM) structure  532 . 
       FIG. 6  illustrates a top view of the display device  500  of  FIG. 5 .  FIG. 6  illustrates a substrate  110 , a plurality of pixel regions  111 , light emission regions Re and non-emission regions Rne of the display device  500  in an embodiment. In the embodiment, the color of the light emitted by the light emitting layer  125  of each pixel structure  120  in the plurality of pixel regions  111  is substantially the same as the filtered color of the color filter element  531  corresponding to the same pixel region  111 . In this embodiment, the light emitting layer  125  of the display device  500  includes a first color light emitting layer (light emission region Re 1 ) for emitting light of a first color, a second color light emitting layer (light emission region Re 2 ) for emitting light of a second color, and a third color light emitting layer (light emission region Re 3 ) for emitting light of a third color in different pixel regions  111 . The first color light emitting layer, the second color light emitting layer, and the third color light emitting layer correspond respectively to three color filter elements having three filtered colors that are the same as the colors of the light emitted by the three color light emitting layers, respectively. As shown in  FIG. 5 , the color filter elements  531  may include a first color filter element  5311 , a second color filter element  5312 , and a third color filter element  5313 . The light emission regions Re 1 , Re 2  and Re 3  are arranged in sequence and repeatedly along a first direction D 1  in  FIG. 6 . The light emission regions Re 1 , Re 2  and Re 3  are arranged with the light emission regions of same light emitting color and repeatedly along a second direction D 2 , as shown in  FIG. 6 . The first direction D 1  is substantially perpendicular to the second direction D 2 . The non-emission regions Rne in each pixel region  111  exhibit the black color due to the disposition of the black matrix structures. The non-emission regions of the first color Rne 1 , the non-emission regions of the second color Rne 2  and the non-emission regions of the third color Rne 3  are as shown in  FIG. 6 . In one embodiment, the first color, the second color and the third color may be red, green and blue, respectively. In other embodiments, the first color, the second color and the third color may be other colors, the scope of the disclosure is not limited thereto. In addition, there are 3 pixel colors in the embodiment, but in other embodiments, the pixel colors may be more or less than 3, the scope of the disclosure is not limited thereto. 
     The arrangements of the pixels of the first color, the second color and the third color illustrated in the embodiment of  FIG. 6  are strip-shaped. In other embodiments (not shown), the arrangement of the 3 pixel colors may be triangle-shaped or a mosaic arrangement, but the scope of the disclosure is not limited thereto. Pixel regions are categorized by their pixel arrangements. That is, pixel regions correspond to pixel arrangements, respectively. Color filter elements  131  also respectively correspond to the pixel arrangements. In a same pixel region, the filtered color of the color filter element  131  is substantially the same as the color of the light emitted by the light emitting layer  125 . 
       FIG. 7  illustrates a display device according to another embodiment of the disclosure. As shown in  FIG. 7 , a display device  700  is similar to the display device  100  in the aforementioned embodiment. The same or similar reference numbers used in each of the following exemplary embodiments represent the same or the like elements, and thus descriptions of the same or the like elements will not be repeatedly provided hereinafter. The difference between the two display devices is that the color filter layer  130  of the display device  700  is disposed between the thin film encapsulation (TFE) layer  150  and the glue  160 . 
     As shown in  FIG. 7 , a display device  700  includes a substrate  110 , a plurality of pixel structures  120  and a color filter layer  530 . The substrate  110  has a plurality of pixel regions  111  thereon. The plurality of pixel structures  120  are respectively disposed on corresponding pixel regions  111 . Each of the pixel structures  120  includes an active device layer  121 , a light absorption layer  122 , an optical matching layer  123 , a first transparent electrode  124 , a light emitting layer  125  and a second transparent electrode  126 . The active device layer  121  is disposed on the substrate  110 , the light absorption layer  122  is disposed on the active device layer  121 , the optical matching layer  123  is disposed on the light absorption layer  122 , the first transparent electrode  124  is disposed on the optical matching layer  123 , the light emitting layer  125  is disposed on the first transparent electrode  124  and the second transparent electrode  126  is disposed on the light emitting layer  125 . The color filter layer  130  covers the plurality of pixel structures  120  and has a plurality of color filter elements  131 . The plurality of color filter elements  131  are correspondingly disposed in the plurality of pixel regions  111 . The display device  700  further includes the pixel define layer (PDL)  140 , the thin film encapsulation (TFE) layer  150 , the glue  160 , the cover  170  and a planarization layer  180 . The plurality of pixel structures  120  of the display device  700  are defined by the pixel define layer (PDL)  140 . The pixel define layer (PDL)  140  is disposed between the light emitting layer  125  and the light absorption layer  122 . The optical matching layer  123  and the first transparent electrode  124  are disposed between the light absorption layer  122  and the pixel define layer (PDL)  140 . The thin film encapsulation (TFE) layer  150  is disposed on the second transparent electrode  126 . The planarization layer  180  is disposed on the thin film encapsulation (TFE) layer  150  and may make the surface more planar, the color filter layer  130  is disposed on the planarization layer  180 , the glue  160  is disposed on the color filter layer  130 , the cover  170  is disposed on the glue  160 . The color filter layer  130  is disposed between the planarization layer  180  and the glue  160 . The thin film encapsulation (TFE) layer  150 , the planarization layer  180 , the color filter layer  130  and the glue  160  are disposed between the second transparent electrode  126  and the cover  170 . 
     In the embodiment of FIG. 7 , the color filter layer  130  is foi ned on the substrate  110 , and then bonding the cover is performed during the process of fabricating the display device  700 . Therefore, after the pixel structures  120 , the pixel define layer (PDL)  140 , the thin film encapsulation (TFE) layer  150 , the planarization layer  180  and the color filter layer  130  are sequentially formed on the substrate  110 , the color filter layer  130  and the cover  170  are bonded with the glue  160 . Thereby, fabricating the display device  700  is done. 
     Please refer to  FIG. 7  again. In a same pixel region  111 , the color of the light emitted by the light emitting layer  125  of the pixel structure  120  is substantially the same as the filtered color of the color filter element  131  (the color that appears after the white color passes through the color filter element  131 ). The color of the light emitted by the light emitting layer  125  of a pixel structure  120  may be the same as or different from the color of the light emitted by the light emitting layer  125  of its one or more neighboring pixel structures  120 . 
     Please refer to  FIG. 2B  again,  FIG. 2B  also illustrates a top view of the display device  700  of  FIG. 7 .  FIG. 2B  illustrates the substrate  110 , the plurality of pixel regions  111 , the light emission region Re and the non-emission region Rne of the display device  700 . In the embodiment, the color of the light emitted by the light emitting layer  125  of the pixel structure  120  is substantially the same as the filtered color of the color filter element  131  in a same pixel region  111 . The light emitting layer  125  of the display device  700  includes a first color light emitting layer (light emission region Re 1 ) for emitting light of a first color, a second color light emitting layer (light emission region Re 2 ) for emitting light of a second color, and a third color light emitting layer (light emission region Re 3 ) for emitting light of a third color, and the three color light emitting layers are in different pixel regions  111 . The first color light emitting layer, the second color light emitting layer, and the third color light emitting layer correspond respectively to three color filter elements having three filtered colors that are the same as the colors of the light emitted by the three color light emitting layers, respectively. As shown in  FIG. 7 , the three color filter elements are a first color filter element  1311 , a second color filter element  1312 , and a third color filter element  1313 , respectively. The light emission regions Re 1 , Re 2  and Re 3  are arranged in sequence and repeatedly along a first direction D 1  shown in  FIG. 2B . The light emission regions Re 1 , Re 2  and Re 3  are arranged with the light emission regions of same light emitting color and repeatedly along a second direction D 2 , as shown in  FIG. 2B . The first direction D 1  is substantially perpendicular to the second direction D 2 . The non-emission region Rne in each pixel region  111  exhibits the filtered color of its corresponding color filter element  131  in the pixel region  111 . The arrangements of the non-emission regions of the first color Rne 1 , the non-emission regions of the second color Rne 2  and the non-emission regions of the third color Rne 3  are as shown in  FIG. 2 . In one embodiment, the first color, the second color and the third color are red, green and blue respectively. In other embodiments, the first color, the second color and the third color may be other colors, but the scope of the disclosure is not limited thereto. In addition, there are 3 kinds of pixel colors in the embodiment, but in other embodiments, the pixel colors may be more or less than 3, the scope of the disclosure is not limited thereto. 
     In one embodiment, the arrangements of the pixels of the first color, the second color and the third color are strip-shaped. In other embodiments (not shown), the arrangement of the 3 pixel colors may be triangle-shaped or a mosaic arrangement, but the scope of the disclosure is not limited thereto. Pixel regions are categorized by their pixel arrangements. That is, pixel regions correspond to pixel arrangements, respectively. Color filter elements  131  also respectively correspond to the pixel arrangements. In a same pixel region, the filtered color of the color filter element  131  is substantially the same as the color of the light emitted by the light emitting layer  125 . 
     The substrate  110 , the active device layer  121 , the light absorption layer  122 , the optical matching layer  123 , the first transparent electrode  124 , the light emitting layer  125 , the second transparent electrode  126 , the color filter layer  130 , the pixel the cover  170  of the display device  700  are the same as those of the display device  100  in the aforementioned embodiments, and thus descriptions of the same or the like elements will not be repeatedly provided hereinafter. 
     As the structure of the display device  700 , the phenomenon that the light emitted by the light emitting layer  125  from one pixel region is emitted from neighboring pixel regions may be reduced, and the crosstalk between pixels may be avoided. 
       FIG. 8  illustrates a display device according to another embodiment of the disclosure. As shown in  FIG. 8 , a display device  800  is similar to the display device  700  in the previous embodiment. The same or similar reference numbers used in each of the following exemplary embodiments represent the same or the like elements, and thus descriptions of the same or the like elements will not be repeatedly provided hereinafter. The difference between the two display devices is that the color filter layer  830  of the display device  800  further includes a plurality of black matrix (BM) structures  832  except the plurality of color filter element  831 . As shown in  FIG. 8 , the display device  800  includes the substrate  110 , the plurality of pixel structures  120  and a color filter layer  830 . The substrate  110  has a plurality of pixel regions  111  thereon. The plurality of pixel structures  120  are correspondingly disposed on the pixel regions  111 , respectively. Each of the pixel structures  120  includes the active device layer  121 , the light absorption layer  122 , the optical matching layer  123 , the first transparent electrode  124 , the light emitting layer  125  and the second transparent electrode  126 . The active device layer  121  is disposed on the substrate  110 , the light absorption layer  122  is disposed on the active device layer  121 , the optical matching layer  123  is disposed on the light absorption layer  122 , the first transparent electrode  124  is disposed on the optical matching layer  123 , the light emitting layer  125  is disposed on the first transparent electrode  124  and the second transparent electrode  126  is disposed on the light emitting layer  125 . The color filter layer  830  covers the plurality of pixel structures  120  and has a plurality of color filter elements  831  and a plurality of black matrix (BM) structures  832 . The plurality of color filter elements  831  are correspondingly disposed in the plurality of pixel regions  111 , respectively. The display device  800  further includes the pixel define layer (PDL)  140 , the thin film encapsulation (TFE) layer  150 , the glue  160 , the cover  170  and the planarization layer  180 . The plurality of pixel structures  120  of the display device  800  are defined by the pixel define layer (PDL)  140 . The pixel define layer (PDL)  140  is disposed between the light emitting layer  125  and the light absorption layer  122 . The optical matching layer  123  and the first transparent electrode  124  are disposed between the light absorption layer  122  and the pixel define layer (PDL)  140 . The thin film encapsulation (TFE) layer  150  is disposed on the second transparent electrode  126 . The planarization layer  180  is disposed on the thin film encapsulation (TFE) layer  150  and may make the surface more planar. The color filter layer  830  is disposed on the glue  160  is disposed on the planarization layer  180 , the glue  160  is disposed on the color filter layer  830 , and the cover  170  is disposed on the glue  160 . The color filter layer  830  is disposed between the planarization layer  180  and the glue  160 . The thin film encapsulation (TFE) layer  150 , the planarization layer  180 , the color filter layer  830  and the glue  160  are disposed between the second transparent electrode  126  and the cover  170 . The disposition of the black matrix (BM) structures  832  may further reduce the reflectance of the ambient light incident to the display device and raise the ambient contrast ratio. 
     Please refer to  FIG. 8  again, in one pixel region  111 , the color of the light emitted by the light emitting layer  125  of each of the plurality of the pixel structures  120  is substantially the same as the filtered color of the color filter element  831 the color that appears after the white color passes through the color filter element  831 ) in the same pixel region  111 . The color of the light emitted by the light emitting layer  125  of a pixel structure  120  in one pixel region  111  may be the same as or different from the color of the light emitted by the light emitting layer  125  of its one or more neighboring the pixel structures  120 . 
     Please refer to  FIG. 6  again.  FIG. 6  also illustrates a top view of the display device  800  of  FIG. 8 .  FIG. 6  illustrates a substrate  110 , a plurality of pixel regions  111 , light emission regions Re and non-emission regions Rne of the display device  800 . In one embodiment, the color of the light emitted by the light emitting layer  125  of each pixel structure  120  is substantially the same as the filtered color of the color filter element  831  in a same pixel region  111 . The light emitting layer  125  of the display device  800  includes a first color light emitting layer (light emission region Re 1 ) for emitting light of first color, a second color light emitting layer (light emission region Ret) for emitting light of second color, and a third color light emitting layer (light emission region Re 3 ) for emitting light of third color in different pixel regions  111 , and the three color light emitting layers are in different pixel regions  111 . The first color light emitting layer, the second color light emitting layer, and the third color light emitting layer correspond respectively to three color filter elements having three filtered colors that are the same as the colors of the light emitted by the three color light emitting layers, respectively. As shown in  FIG. 8 , the color filter elements  831  may include a first color filter element  8311 , a second color filter element  8312 , and a third color filter element  8313 . The light emission regions Re 1 , Re 2  and Re 3  are arranged in sequence and repeatedly along a first direction D 1  in  FIG. 6 . The light emission regions Rel, Re 2  and Re 3  are arranged with the light emission regions of same light emitting color and repeatedly along a second direction D 2 , as shown in  FIG. 6 . The first direction D 1  is substantially perpendicular to the second direction D 2 . The non-emission region Rne in each pixel region  111  exhibit the black color due to the disposition of the black matrix structure. The non-emission regions of the first color Rne 1 , the non-emission regions of the second color Rne 2  and the non-emission regions of the third color Rne 3  are as shown in  FIG. 6 . In one embodiment, the first color, the second color and the third color may be red, green and blue, respectively. In other embodiments, the first color, the second color and the third color may be other colors, the scope of the disclosure is not limited thereto. In addition, there are 3 pixel colors in the embodiment, but in other embodiments of the display device  800 , the pixel colors may be more or less than 3, the scope of the disclosure is not limited thereto. 
     In one embodiment, the arrangements of the pixels of the first color, the second color and the third color are strip-shaped. In other embodiments (not shown), the arrangement of the 3 pixel colors may be triangle-shaped or a mosaic arrangement, but the scope of the disclosure is not limited thereto. Pixel regions are categorized by their pixel arrangements. That is, pixel regions correspond to pixel arrangements, respectively. Color filter elements  831  also respectively correspond to the pixel arrangements. In a same pixel region, the filtered color of the color filter element  831  is substantially the same as the color of the light emitted by the light emitting layer  125 . 
     According to the aforementioned embodiments of the disclosure, the embodiments provide displays with a high output luminance, a high ambient contrast ratio and a high color purity. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments. It is intended that the specification and examples be considered as exemplary embodiments only, with a scope of the disclosure being indicated by the following claims and their equivalents.