Patent Publication Number: US-11659755-B2

Title: Display device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of China application no. 202010371932.2, filed on May 6, 2020. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     TECHNICAL FIELD 
     The disclosure relates to a display device. 
     BACKGROUND 
     As the application of display devices continues to expand, the development of display technology is also changing with each passing day. With different application conditions, the display devices will also face different problems. Therefore, the research and development of display devices must be continuously updated and adjusted. 
     SUMMARY 
     The disclosure provides a display device having a preferable display quality. 
     According to an embodiment of the disclosure, the display device includes a red pixel unit, a green pixel unit and a blue pixel unit. The red pixel unit includes a light emitting element, a light conversion element and a color filter, wherein the light emitting element emits blue light that then passes through the light conversion element and the color filter and the blue light is converted into a red light while passing through the light conversion element. The green pixel unit includes a light emitting element, a light conversion element and a color filter, wherein the light emitting element emits a blue light that then passes through the light conversion element and the color filter and the blue light is converted into a green light while passing through the light conversion element. The blue pixel unit which includes a light emitting element and a color filter, wherein the light emitting element emits a blue light that then passes through the color filter. The red pixel unit has a lighting area greater than a lighting area of the blue pixel unit and less than a lighting area of the green pixel unit. 
     To make the aforementioned more comprehensible, several embodiments accompanied with drawings are described in detail as follows. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of the specification. The drawings illustrate embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure. 
         FIG.  1 A  is a partial view of a display device in lit state according to an embodiment of the disclosure. 
         FIG.  1 B  is a partial view of a display device in lit state according to an embodiment of the disclosure. 
         FIG.  1 C  is a partial view of a display device in lit state according to an embodiment of the disclosure. 
         FIG.  2 A  is a partial cross-sectional view of a display device according to an embodiment. 
         FIG.  2 B  is a partial cross-sectional view of a display device according to an embodiment. 
         FIG.  2 C  is a partial cross-sectional view of a display device according to an embodiment. 
         FIG.  3 A  to  FIG.  3 G  are partial cross-sectional views of a display device according to an embodiment of the disclosure. 
         FIG.  4 A  to  FIG.  4 F  are cross-sectional views of a display device according to an embodiment of the disclosure. 
         FIG.  5 A  to  FIG.  5 J  are cross-sectional views of a display device according to an embodiment of the disclosure. 
         FIG.  6 A  to  FIG.  6 C  are cross-sectional views of a display device according to an embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The disclosure may be understood with reference to the following detailed description and the accompanying drawings. It should be noted that, for ease of understanding by readers and concise drawings, a plurality of drawings in the disclosure merely show a part of an electronic device, and specific elements in the drawings are not drawn to scale. In addition, the quantity and size of the elements in the drawings are merely exemplary, and are not intended to limit the scope of the disclosure. 
     Some words are used to refer to specific elements in the whole specification and the appended claims in the disclosure. A person skilled in the art should understand that an electronic device manufacturer may use different names to refer to the same elements. The specification is not intended to distinguish elements that have the same functions but different names. In the specification and the claims, words such as “include”, “comprise”, and “have” are open words, and should be interpreted as “including, but not limited to”. Therefore, when terms “include”, “comprise”, and/or “have” are used in the description of the disclosure, the presence of corresponding features, regions, steps, operations and/or components is specified without excluding the presence of one or more other features, regions, steps, operations and/or components. 
     The directional terms mentioned herein, like “above”, “below”, “front”, “back”, “left”, and “right”, refer to the directions in the accompanying drawings. Therefore, the directional terms are used for illustration instead of limiting the disclosure. In the accompanying drawings, common features of a method, a structure and/or a material used in a specific embodiment are shown in the drawings. However, these drawings should not be construed as defining or limiting the scope or nature of these embodiments. For example, the relative sizes, thicknesses and positions of films, regions and/or structures may be reduced or enlarged for clarity. 
     When a corresponding component (e.g., a film or a region) is referred to as being “disposed or formed on another component”, it may be directly on the another component, or there may be other components between the two components. In another aspect, when a component is referred to as being “directly disposed or formed on another component”, there is no component between the two components. In addition, when a component is referred to as being “disposed or formed on another component”, the two components have an up and down relationship in a top view. The component may be located above or below the another component, and the up and down relationship depends on the orientation of the device. 
     It should be understood that, when a component or a film is referred to as being “connected to” another component or film, it may be directly connected to the another component or film, or there are components or films inserted between the two components or films. When a component or a film is referred to as being “directly connected to” another component or film, there is no component or film inserted between the two components or films. In addition, when a component is referred to as being “coupled to another component (or a variant thereof)”, it may be directly connected to the another component, or may be indirectly connected to (e.g., electrically connected to) the another component through one or more components. 
     The terms “approximately”, “equal to”, “identical to” or “the same as”, or “substantially” or “generally” are generally interpreted as within 20% of the given value or range, or interpreted as within 10%, 5%, 3%, 2%, 1%, or 0.5% of the given value or range. 
     Ordinal numbers used in the specification and the claims, like “first” and “second”, are used to modify the elements, and do not imply or represent that the (or these) element(s) has (or have) any ordinal number, and do not indicate any order between an element and another element, or an order in a manufacturing method. These ordinal numbers are merely used to clearly distinguish an element having a name with another element having the same name. Different terms may be used in the claims and the specification, so that a first component in the specification may be a second component in the claims. 
     It should be noted that in the following embodiments, features in a plurality of embodiments may be replaced, recombined, or mixed to complete other embodiments without departing from the spirit of the disclosure. The features of the embodiments may be used in any combination without departing from the spirit of the disclosure or conflicting with each other. 
       FIG.  1 A  is a partial view of a display device in lit state according to an embodiment of the disclosure. In  FIG.  1 A , a display device  100 A includes a red pixel unit  102 A, a green pixel unit  104 A and a blue pixel unit  106 A. When the display device  100 A is lit, lit screens presented by the red pixel unit  102 A, the green pixel unit  104 A and the blue pixel unit  106 A may be observed under an optical microscope. The outline of each lit screen observed under the microscope may define a lighting area RA of the red pixel unit  102 A, a lighting area GA of the green pixel unit  104 A and a lighting area BA of the blue pixel unit  106 A. For example, an observer may take a photo of the lit screens of the display device  100 A under microscope observation, and determine the outline of the lighting area for each color in the taken photo to define the lighting areas. In some embodiments, the lighting area RA, the lighting area GA, and the lighting area BA are different from each other. In addition, the display device  100 A may be provided with a black matrix  108 A to space apart the red pixel unit  102 A, the green pixel unit  104 A and the blue pixel unit  106 A from each other, but not limited thereto. In some embodiments, the black matrix  108 A may be omitted. In some embodiments, the lighting area RA, the lighting area GA and the lighting area BA may be different from actual lighting areas of the red pixel unit  102 A, the green pixel unit  104 A and the blue pixel unit  106 A. For example, the lighting area RA may be greater than or less than an area of a region of the red pixel unit  102 A not covered by the black matrix  108 A; the lighting area GA may be greater than or less than an area of a region of the green pixel unit  104 A not covered by the black matrix  108 A; and/or the lighting area BA may be greater than or less than an area of a region of the blue pixel unit  106 A not covered by the black matrix  108 A. Nonetheless, in some other embodiments, the lighting area RA may be equal to the area of the region of the red pixel unit  102 A not covered by the black matrix  108 A; the lighting area GA may be equal to the area of the region of the green pixel unit  104 A not covered by the black matrix  108 A; and/or the lighting area BA may be equal to the area of the region of the blue pixel unit  106 A not covered by the black matrix  108 A. 
     In an embodiment, each of the lighting area RA of the red pixel unit  102 A, the lighting area GA of the green pixel unit  104 A and the lighting area BA of the blue pixel unit  106 A may substantially present a rectangular outline when viewed under the optical microscope. The rectangular outline formed by each of the lighting area RA, the lighting area GA and the lighting area BA has, for example, approximately the same length LA. In addition, a width W 102 A of the rectangular outline formed by the lighting area RA may be greater than a width W 106 A of the rectangular outline formed by the lighting area BA and less than a width W 104 A of the rectangular outline formed by the lighting area GA. Accordingly, the red pixel unit  102 A has the lighting area RA greater than the lighting area BA of the blue pixel unit  106 A and less than the lighting area GA of the green pixel unit  104 A, but not limited thereto. For brevity of description, in the following part of the description, the element symbols RA GA, and BA will be used to represent the lighting areas of the pixel units of different colors instead repeatedly describing them as the lighting area of the red pixel unit and the blue light emitting unit and the lighting area of the green pixel unit. That is to say, the lighting area RA is the lighting area of the red pixel unit; the lighting area GA is the lighting area of the green pixel unit; and the lighting area BA is the lighting area of the blue pixel unit. 
     In some embodiments, a ratio of the lighting area GA of the green pixel unit  104 A to the lighting area RA of the red pixel unit  102 A is, for example, ranged from 1.02 to 2.90 or ranged from 1.37 to 2.07. In some embodiments, a ratio of the lighting area GA of the green pixel unit  104 A to the lighting area BA of the blue pixel unit  106 A is, for example, ranged from 1.68 to 3.29 or ranged from 1.71 to 2.35. In some embodiments, a ratio of the lighting area RA of the red pixel unit  102 A to the lighting area BA of the blue pixel unit  106 A is, for example, ranged from 1.02 to 1.84 or ranged from 1.03 to 1.37. 
       FIG.  1 B  is a partial view of a display device in lit state according to an embodiment of the disclosure. In  FIG.  1 B , a display device  100 B is similar to the display device  100 A, and the difference between the two embodiments of  FIG.  1 A  and  FIG.  1 B  is mainly the outlines of the lighting areas when the pixel units are lit. In  FIG.  1 B , the display device  100 B includes a red pixel unit  102 B, a green pixel unit  104 B, a blue pixel unit  106 B and a black matrix  108 B. Here, the black matrix  108 B spaces apart the red pixel unit  102 B, the green pixel unit  104 B and the blue pixel unit  106 B from each other. However, in some embodiments, the black matrix  108 B may be omitted. When the display device  100 B is lit, a lighting area RB of the red pixel unit  102 B, a lighting area GB of the green pixel unit  104 B and a lighting area BB of the blue pixel unit  106 B may be observed under the optical microscope. In some embodiments, the lighting area RB, the lighting area GB and the lighting area BB are different from each other. 
     A ratio of the lighting area GB of the green pixel unit  104 B to the lighting area RB of the red pixel unit  102 B is, for example, ranged from 1.02 to 2.90 or ranged from 1.37 to 2.07. In some embodiments, a ratio of the lighting area GB of the green pixel unit  104 B to the lighting area BB of the blue pixel unit  106 B is, for example, ranged from 1.68 to 3.29 or ranged from 1.71 to 2.35. In some embodiments, a ratio of the lighting area RB of the red pixel unit  102 B to the lighting area BB of the blue pixel unit  106 B is, for example, ranged from 1.02 to 1.84 or ranged from 1.03 to 1.37. 
     In this embodiment, each of the outlines of the lighting area RB, the lighting area GB and the lighting area BB observed under the optical microscope forms an irregular geometric shape, such as a P-like shape. In order to explain a measurement example of the lighting areas, each of the outlines of the lighting area RB, the lighting area GB and the lighting area GB is substantially divided into a plurality of sub portions of approximately rectangular outlines. For instance, the outline formed by the lighting area RB is divided into a sub portion RB 1  and a sub portion RB 2 ; the outline formed by the lighting area GB is divided into a sub portion GB 1  and a sub portion GB 2 ; and the outline formed by the lighting area BB is divided into a sub portion BB 1  and a sub portion BB 2 . The sub portion RB 1 , the sub portion GB 1  and the sub portion BB 1  have the same length LB 1 ; the sub portion RB 2 , the sub portion GB 2  and the sub portion BB 2  have the same length LB 2 , but not limited thereto. The length LB 1  of the sub portion RB 1  is longer than the length LB 2  of the sub portion RB 2  to form the P-like shape. The length LB 1  of the sub portion GB 1  is longer than the length LB 2  of the sub portion GB 2  to form the P-like shape. The length LB 1  of the sub portion BB 1  is longer than the length LB 2  of the sub portion BB 2  to form the P-like shape. In addition, the sub portion RB 1  has a width W 102 B 1 , and the sub portion RB 2  has a width W 102 B 2 . The width W 102 B 1  may be greater than the width W 102 B 2 , but not limited thereto. The sub portion GB 1  has a width W 104 B 1 , and the sub portion GB 2  has a width W 104 B 2 . The width W 104 B 2  may be greater than the width W 104 B 1 , but not limited thereto. The sub portion BB 1  has a width W 106 B 1 , and the sub portion BB 2  has a width W 106 B 2 . The width W 106 B 1  may be greater than the width W 106 B 2 , but not limited thereto. The relationship between the lengths and widths describe above is simply an exemplary embodiment illustrating the outlines of the lighting areas, but the disclosure is not limited thereto. 
       FIG.  1 C  is a partial view of a display device in lit state according to an embodiment of the disclosure. In  FIG.  1 C , a display device  100 C is similar to the display device  100 A, and the difference between the two embodiments of  FIG.  1 A  and  FIG.  1 C  is mainly the outlines of the lighting areas when the pixel units are lit. In  FIG.  1 C , the display device  100 C includes a red pixel unit  102 C, a green pixel unit  104 C, a blue pixel unit  106 C and a black matrix  108 C. Here, the red pixel unit  102 C, the green pixel unit  104 C and the blue pixel unit  106 C are spaced apart from each other by the black matrix  108 C. However, in some embodiments, the black matrix  108 C may be omitted. 
     When the display device  100 C is lit, it may be observed under the microscope that, the red pixel unit  102 C includes a lighting area RC; the green pixel unit  104 C includes a lighting area GC; and the blue pixel unit  106 C includes a lighting area BC. As can be seen from  FIG.  1 C , the lighting area GC of the green pixel unit  104 C may be divided into a sub lighting area GC 1  and a sub lighting area GC 2 . In an embodiment, a size of the lighting area GC of the green pixel unit  104 C may be a sum of the sub lighting area GC 1  and the sub lighting area GC 2 . In some embodiments, the lighting area RC of the red pixel unit  102 C may be less than the lighting area GC of the green pixel unit  104 C. In addition, the lighting area RC of the red pixel unit  102 C may be greater than the lighting area BC of the blue pixel unit  106 C. In some embodiments, the ratios of the lighting area RC, the lighting area GC and the lighting area BC may refer to the description of the foregoing embodiments. For example, the ratio of the lighting area GB to the lighting area RB (the lighting area GB/the lighting area RB) may be, for example, ranged from 1.02 to 2.90 or ranged from 1.37 to 2.07. The ratio of the lighting area GB to the lighting area BB (the lighting area GB/the lighting area BB) may be, for example, ranged from 1.68 to 3.29 or ranged from 1.71 to 2.35. The ratio of the lighting area RB to the lighting area BB (the lighting area RB/the lighting area BB) may be, for example, ranged from 1.02 to 1.84 or ranged from 1.03 to 1.37, but not limited thereto. 
       FIG.  2 A  is a partial cross-sectional view of a display device according to an embodiment of the disclosure. A cross-sectional structure of  FIG.  2 A  schematically shows some components of a display device. A display device  200 A may include, for example, a red pixel unit  202 A, a green pixel unit  204 A, a blue pixel unit  206 A, a black matrix  208 A and a substrate  210 . Further, the red pixel unit  202 A, the green pixel unit  204 A, the blue pixel unit  206 A and the black matrix  208 A are all disposed on a first side SA of the substrate  210 . 
     The red pixel unit  202 A of the display device  200 A includes, for example, a light emitting element E 202 A, a light conversion element Q 202 A and a color filter C 202 A. The light emitting element E 202 A emits a light R 202 . After being emitted from the light emitting element E 202 A, the light R 202  then passes through the light conversion element Q 202 A and the color filter C 202 A, and the light R 202  is converted into a red light while passing through the light conversion element Q 202 A. In some embodiments, the light passed through the light conversion element Q 202 A may contain the blue light not converted by the light conversion element Q 202 A. In this case, the color filter C 202 A may filter or suppress the blue light not converted by the light conversion element Q 202 A. Therefore, a pixel light L 202  emitted by the red pixel unit  202 A is the red light or a red light containing a small amount of the blue light. That is to say, the pixel light L 202  is a pure red light or a red light with a small amount of leaking blue light. The pure red light may be exemplified as conforming to the red in the color standard established by the International Telecommunication Union BT.2020 (ITU-R Recommendation BT.2020). 
     The green pixel unit  204 A of the display device  200 A includes, for example, a light emitting element E 204 A, a light conversion element Q 204 A and a color filter C 204 A. The light emitting element E 204 A emits a light R 204 . After being emitted from the light emitting element E 204 A, the light R 204  then passes through the light conversion element Q 204 A and the color filter C 204 A, and the light R 204  is converted into a green light while passing through the light conversion element Q 204 A. In some embodiments, the light passed through the light conversion element Q 204 A may contain the blue light not converted by the light conversion element Q 204 A. In this case, the color filter C 204 A may filter or suppress the blue light not converted by the light conversion element Q 204 A. Therefore, a pixel light L 204  emitted by the green pixel unit  204 A is the green light or a green light containing a small amount of blue light. That is to say, the pixel light L 204  is a pure green light or a green light with a small amount of leaking blue light. The pure green light may be exemplified as conforming to the green in the color standard established by the International Telecommunication Union BT.2020 (ITU-R Recommendation BT.2020). 
     The blue pixel unit  206 A includes a light emitting element E 206 A and a color filter C 206 A. The light emitting element E 206 A emits a light R 206 , and after being emitted from the light emitting element E 206 A, the light R 206  then passes through the color filter C 206 A. In some embodiments, the color filter C 206 A may be a transparent filling element, or may be a filling element with scattering particles, but not limited thereto. Furthermore, the color filter C 206 A may be adjusted according to optical requirements and may completely fill, partially or partially fill an opening AB defined by the black matrix  208 A. For example, in the opening AB of  FIG.  2 A , the color filter C 206 A does not fill the entire opening AB. In some embodiments, the light R 206  passed through the color filter C 206 A may also be filtered or absorbed by the color filter C 206 A. In this way, a pixel light L 206  emitted by the blue pixel unit  206 A is a blue light. 
     The light emitting element E 202 A, the light emitting element E 204 A and the light emitting element E 206 A may be elements such as organic light emitting elements, micro light emitting elements or the like, but not limited thereto. The light conversion element Q 202 A of the red pixel unit  202 A and the light conversion element Q 204 A of the green pixel unit  204 A may convert, for example, short-wavelength light into long-wavelength light to achieve light conversion. The light conversion element Q 202 A and the light conversion element Q 204 A may comprise a matrix material and a light conversion material dispersed in the matrix material. Among them, the matrix material comprises an organic transparent material; the light conversion material includes a fluorescent material, a phosphorescent material, a quantum dot material, other suitable material or a combination of the foregoing materials, but not limited thereto. When the materials of the light conversion element Q 202 A and the light conversion element Q 204 A are the quantum dot material, the light conversion element Q 202 A and the light conversion element Q 204 A may emit a red light, a green light, a blue light or other color light based on the selection of the quantum dot material (e.g., an adjustment of particle size). For example, the quantum dot material may be used to convert short-wavelength light such as a blue light or an ultraviolet light into longer-wavelength light such as a red light, a yellow light and a green light. In some embodiments, the light R 202  and the light R 204  emitted by the light emitting element E 202 A and the light emitting element E 204 A may be the blue light or the ultraviolet light, and the light R 206  emitted by the light emitting element E 206 A is, for example, the blue light. 
     The color filter C 202 A of the red pixel unit  202 A is, for example, a red filter, and its material comprises a photoresist material or an ink material. The color filter C 204 A of the green pixel unit  204 A is, for example, a green filter, and its material comprises a photoresist material or an ink material. The color filter C 206 A of the blue pixel unit  206 A is, for example, a blue filter, and its material comprises a photoresist material or an ink material or a filling element with scattering particles, but not limited thereto. In some embodiments, the color filter C 206 A may comprise a transparent material, which allows the light R 206  of the light emitting element E 206 A to pass through without providing color filtering. In an alternative embodiment, the color filter C 206 A may be doped with scattering particles to diverge the light R 206  from the light emitting element E 206 A. In addition, the light conversion element Q 202 A and the light conversion element Q 204 A may also be doped with scattering particles. In some embodiments, a material of scattering particles may comprise TiO 2  or contain titanium (Ti), zirconium (Zr), aluminum (Al), indium (In), zinc (Zn), tin (Sn), antimony (Sb), silicon (Si), gold (Au), silver (Ag), copper (Cu), platinum (Pt), iron (Fe), cobalt (Co), nickel (Ni) and manganese (Mn). 
     In  FIG.  2 A , the light emitting element E 202 A, the light emitting element E 204 A and the light emitting element E 206 A are schematically represented by rectangular patterns. However, specific structures of the light emitting element E 202 A, the light emitting element E 204 A and the light emitting element E 206 A may vary according to different implementations. In addition, in order to present the lights R 202 , R 204  and R 206 ,  FIG.  2 A  simply schematically shows arrangement positions of the light emitting element E 202 A, the light emitting element E 204 A and the light emitting element E 206 A relative to other components without directly showing their actual arrangements. In  FIG.  2 A , the black matrix  208 A disposed on the first side SA of the substrate  210  forms openings AR, AG and AB. The color filter C 202 A and the light conversion element Q 202 A of the red pixel unit  202 A are disposed in the opening AR, and the color filter C 202 A is disposed between the light conversion element Q 202 A and the substrate  210 . In addition, the color filter C 202 A and the light conversion element Q 202 A of the red pixel unit  202 A are both disposed between the light emitting element E 202 A and the substrate  210 . The color filter C 204 A and the light conversion element Q 204 A of the green pixel unit  204 A are disposed in the opening AG, and the color filter C 204 A is disposed between the light conversion element Q 204 A and the substrate  210 . In addition, the color filter C 204 A and the light conversion element Q 204 A of the green pixel unit  204 A are both disposed between the light emitting element E 204 A and the substrate  210 . The color filter C 206 A of the blue pixel unit  206 A is disposed in the opening AB, and the color filter C 206 A of the blue pixel unit  206 A is disposed between the light emitting element E 206 A and the substrate  210 . In addition, the display device  200 A may include a passivation layer PV that covers the light conversion element Q 202 A, the light conversion element Q 204 A and the light conversion element C 206 A In some embodiments, the color filter C 202 A and the light conversion element Q 202 A are stacked together and an overall thickness of the two may be greater than a thickness of the black matrix  208 A; and/or the color filter C 204 A and the light conversion element Q 204 A are stacked together and an overall thickness of the two may be greater than the thickness of the black matrix  208 A, but not limited thereto. In some other embodiments, the overall thickness the color filter C 202 A and the light conversion element Q 202 A may be less than the thickness of the black matrix  208 A; and/or the overall thickness the color filter C 204 A and the light conversion element Q 204 A may be less than the thickness of the black matrix  208 A. In some embodiments, the thickness of the black matrix  208 A may be determined based on the fabrication method of the black matrix  208 A. The fabrication method of the black matrix  208 A may include a photolithography process, an ink-ject printing process, a method combined the photolithography process and the ink-ject printing process, or other alternative methods. 
     In an embodiment, a lighting area RD of the red pixel unit  202 A, a lighting area GD of the green pixel unit  204 A and a lighting area BD of the blue pixel unit  206 A may be understood as sizes of lighting regions observed from a second side SB of the substrate  210  when the red pixel unit  202 A, the green pixel unit  204 A and the blue pixel unit  206 A are lit. As can be seen from  FIG.  2 A , the black matrix  208 A surrounds the red pixel unit  202 A; the green pixel unit  204 A and the blue pixel unit  206 A; and the black matrix  208 A has the function of covering light, preventing from a light leakage, preventing from mixing of different colored light generated by different ones of the red, green, and blue pixel units, or a combination thereof. Accordingly, in other embodiments, the lighting area RD of the red pixel unit  202 A, the lighting area GD of the green pixel unit  204 A and the lighting area BD of the blue pixel unit  206 A may also be respectively understood as a size of the opening AR of the black matrix  208 A corresponding to the red pixel unit  202 A on the first side SA of the substrate  210 , a size of the opening AG of the black matrix  208 A corresponding to the green pixel unit  204 A on the first side SA of the substrate  210  and a size of the opening AB of the black matrix  208 A corresponding to the blue pixel unit  206 A on the first side SA of the substrate  210 . The above two definitions of the lighting areas are included in the scope of the disclosure. 
     With different applications, a display effect of the display device  200 A may be specified. In some embodiments, with a white point displayed by the display device  200 A in the CIE1931 colorimeter system as an example, the X coordinate may be specified as 0.273±0.020 and the Y coordinate may be specified as 0.275±0.020. In some applications, a peak wavelength of red light may be set to 630±20 nanometers (nm); a peak wavelength of green light may be set to 532±20 nanometers (nm); and a peak wavelength of blue light may be set to 450±20 nanometers (nm), but not limited thereto. In addition, to achieve the white point with the X coordinate as 0.273±0.020 and the Y coordinate as 0.275±0.020 in the CIE1931 colorimeter system, a target radiation weight percentage (light intensity ratio) of the red light (e.g., the pixel light L 202 ) is set to 20%, for example; a target radiation weight percentage of the green light (e.g., the pixel light L 204 ) is set to 29%, for example; and a target radiation weight percentage of the blue light (e.g., the pixel light L 206 ) is set to 51%, for example. 
     In this embodiment, the pixel light L 202 , the pixel light L 204  and the pixel light L 206  are originated from the light R 202  of the light emitting element E 202 A, the light R 204  of the light emitting element E 204 A and the light R 206  of the light emitting element E 206 A, respectively. However, because the light emitting element E 202 A, the light emitting element E 204 A and the light emitting element E 206 A have substantially similar or even the same light emitting efficiency, the influence of the light R 202 , the light R 204  and the light R 206  on the radiation weight percentages of different color light may be ignored. Nonetheless, a radiation of the pixel light L 202  may be affected by a conversion efficiency of the light conversion element Q 202 A and a transmittance of the color filter C 202 A; a radiation of the pixel light L 204  may be affected by a conversion efficiency of the light conversion element Q 204 A and a transmittance of the color filter C 204 A; and a radiation of the pixel light L 206  may be affected by a transmittance of the color filter C 206 A. Therefore, in order to achieve the target radiation weight percentages, the radiation weight percentage of each color light may be designed according to a formula below: (a design radiation weight percentage) proportional to (the target radiation weight percentage)/(the conversion efficiency of the light conversion element*the transmittance of the color filter). 
     In some embodiments, because the radiation of each color light is proportional to the lighting area of each color light, the design radiation weight percentage obtained by the above formula may be used as a parameter for designing the ratio of the lighting area of each color light. Here, for the pixel units having the color filter and the light conversion element stacked together, the transmittance of the color filter may be defined as a ratio of a light intensity of the light passed through the light conversion element to a light intensity of the light further passed through the color filter after being passed through the light conversion element. However, the transmittance may also be defined by other definitions known in the industry. 
     In some embodiments, a light conversion efficiency (External Quantum Efficiency, EQE) of the light conversion element Q 202 A in the red pixel unit  202 A is approximately 24% to 39%, and a light conversion efficiency of the light conversion element Q 204 A in the green pixel unit  204 A is approximately 20% to 35%. The transmittance of the color filter C 202 A in the red pixel unit  202 A is approximately 90%, and the transmittance of the color filter C 204 A in the green pixel unit  204 A is approximately 85%. Meanwhile, the transmittance of the color filter C 206 A in the blue pixel unit  206 A is approximately 90% since the scattering particles in the color filter C 206 A, for example having a material of TiO 2  may absorb around 10% of the blue light emitted from the light emitting element E 206 A. By substituting the transmittance of the color filter and the light conversion efficiency of the light conversion element described above into the formula: (the design radiation weight percentage) proportional to (the target radiation weight percentage)/(the conversion efficiency of the light conversion element×the transmittance of the color filter), the design radiation weight percentage of each color pixel unit for achieving the target radiation weight percentages may be obtained and served as the parameters for designing and manufacturing. For instance, to achieve the target radiation weight percentages of the red light, the green light and the blue light which are at 20%, 29% and 51% and present the white point with the X coordinate as 0.273±0.020 and the Y coordinate as 0.275±0.020 in the CIE1931 colorimeter system, these values may be substituted in the formula to obtain the following results. The design radiation weight percentage of the red pixel unit  202 A is approximately 58% to 94%. The design radiation weight percentage of the green pixel unit  204 A is approximately 96% to 168%. The design radiation weight percentage of the blue pixel unit  206 A is approximately 51% to 57%. Results obtained by dividing the design radiation weight percentages of different color pixel units may be used as the ratios of lighting areas of different color pixel units. Therefore, in order to achieve the radiation weight percentages of the red light, the green light and the blue light which are at 20%, 29% and 51%, and present the white point with the X coordinate as 0.273±0.020 and the Y coordinate as 0.275±0.020 in the CIE1931 colorimeter system, a ratio of the lighting area GD of the green pixel unit  204 A to the lighting area RD of the red pixel unit  202 A (the lighting area GD of the green pixel unit  204 A/the lighting area RD of the red pixel unit  202 A) is, for example, ranged from the 1.02 to 2.90; a ratio of the lighting area GD of the green pixel unit  204 A to the lighting area BD of the blue pixel unit  206 A (the lighting area GD of the green pixel unit  204 A/the lighting area BD of the blue pixel unit  206 A) is, for example, ranged from the 1.68 to 3.29; and/or a ratio of the lighting area RD of the green pixel unit  202 A to the lighting area BD of the blue pixel unit  206 A (the lighting area RD of the green pixel unit  202 A/the lighting area BD of the blue pixel unit  206 A) is, for example, ranged from the 1.02 to 1.84. 
     In some embodiments, a light conversion efficiency of the light conversion element Q 202 A in the red pixel unit  202 A is approximately 32% to 39%, and a light conversion efficiency of the light conversion element Q 204 A in the green pixel unit  204 A is approximately 28% to 35%. The transmittance of the color filter C 202 A in the red pixel unit  202 A is approximately 90%, and the transmittance of the color filter C 204 A in the green pixel unit  204 A is approximately 85%. Meanwhile, the transmittance of the color filter C 206 A (or the filling element) in the blue pixel unit  206 A is approximately 92% since the scattering particles in the color filter C 206 A, for example having a material of TiO 2  may absorb around 8% of the blue light emitted from the light emitting element E 206 A. By substituting the transmittance of the color filter and the light conversion efficiency of the light conversion element described above into the formula: (the design radiation weight percentage) proportional to (the target radiation weight percentage)/(the conversion efficiency of the light conversion element*the transmittance of the color filter), when the target radiation weight percentages of the red light, the green light and the blue light are at 20%, 29% and 51%, the design radiation weight percentage of each color pixel unit may be calculated and served as the parameters for designing and manufacturing. For instance, in order to achieve the radiation weight percentages of the red light, the green light, and the blue light which are at 20%, 29% and 51% and to present the white point with the X coordinate as 0.273±0.020 and the Y coordinate as 0.275±0.020 in the CIE1931 colorimeter system, the design radiation weight percentage of the red pixel unit  202 A is approximately 58% to 70%; the design radiation weight percentage of the green pixel unit  204 A is approximately 96% to 120%; and the design radiation weight percentage of the blue pixel unit  206 A is approximately 51% to 56%. Results obtained by dividing the design radiation weight percentages of different color pixel units may be used as the ratios of lighting areas of different color pixel units. Specifically, in order to achieve the radiation weight percentages of the red light, the green light and the blue light which are at 20%, 29% and 51% and to present the white point with the X coordinate as 0.273±0.020 and the Y coordinate as 0.275±0.020 in the CIE1931 colorimeter system, the ratio of the lighting area GD of the green pixel unit  204 A to the lighting area RD of the red pixel unit  202 A (the lighting area GD of the green pixel unit  204 A/the lighting area RD of the red pixel unit  202 A) is, for example, ranged from the 1.37 to 2.07; the ratio of the lighting area GD of the green pixel unit  204 A to the lighting area BD of the blue pixel unit  206 A (the lighting area GD of the green pixel unit  204 A/the lighting area BD of the blue pixel unit  206 A) is, for example, ranged from the 1.71 to 2.35; and/or the ratio of the lighting area RD of the green pixel unit  202 A to the lighting area BD of the blue pixel unit  206 A (the lighting area RD of the green pixel unit  204 A/the lighting area BD of the blue pixel unit  206 A) is, for example, ranged from the 1.03 to 1.37. 
     The values in the above ranges are for illustrative purposes, and this disclosure is not intended to exclude other specific embodiments for the ratio of the areas. In addition, the outlines of the lighting area RA, the lighting area GA and the lighting area BA are not limited to rectangles, but may have other arbitrary shapes. 
       FIG.  2 B  is a partial cross-sectional view of a display device. A cross-sectional structure of  FIG.  2 B  schematically shows some components of a display device. Since a display device  200 B is similar to the display device  200 A, the same element symbol table i used in the two embodiments to refer to the same elements. Specifically, the display device  200 B includes a red pixel unit  202 B, a green pixel unit  204 B, the blue pixel unit  206 A, a black matrix  208 B and the substrate  210 . The red pixel unit  202 B includes the light emitting element E 202 A, the light conversion element Q 202 A and a color filter C 202 B. The green pixel unit  204 B includes the light emitting element E 204 A, the light conversion element Q 204 A and a color filter C 204 B. The blue pixel unit  206 A includes the light emitting element E 206 A and the color filter C 206 A. The relationship between the sizes of the lighting areas of the red pixel unit  202 B, the green pixel unit  204 B and the blue pixel unit  206 A may refer to the foregoing embodiments, which is not repeated hereinafter. In this embodiment, a peripheral portion C 202 B 1  may be simultaneously fabricated on the substrate  210  when fabricating the color filter C 202 B, and a peripheral portion C 204 B 1  may be simultaneously fabricated on the substrate  210  when fabricating the color filter C 204 B. The peripheral portion C 202 B 1  may be disposed around the color filter C 202 B, and the peripheral portion C 204 B 1  may be disposed around the color filter C 204 B. Meanwhile, the peripheral portion C 204 B 1  may be stacked together with the peripheral portion C 202 B 1  to form the black matrix  208 B. 
       FIG.  2 C  is a partial cross-sectional view of a display device. A cross-sectional structure of  FIG.  2 C  schematically shows some components of a display device. Since a display device  200 C is similar to the display device  200 A, the same element symbol table is used in the two embodiments to refer to the same elements. Specifically, the display device  200 C includes the red pixel unit  202 A, the green pixel unit  204 A, the blue pixel unit  206 A and the substrate  210 . The main difference between the display device  200 C and the display device  200 A is that the display device  200 C does not include the black matrix. 
     In this embodiment, a width of the color filter C 202 A of the red pixel unit  202 A may be greater than a width of the light conversion element Q 202 A, and a width of the color filter C 204 A of the green pixel unit  204 A may be greater than a width of the light conversion element Q 204 A. In some embodiments, a distance DW between an edge of the light conversion element Q 202 A and an edge of the color filter C 202 A may be approximately 1 μm to 5 μm. Similarly, a distance between an edge of the light conversion element Q 204 A and an edge of the color filter C 204 A may also be approximately 1 μm to 5 μm. In some embodiments, the light conversion element Q 202 A and the light conversion element Q 204 A may have inclined sidewalls, and an interior angle formed by the inclined sidewalls and a top surface of the color filter thereunder is an acute angle. Here, an angle of the inclined angle of the sidewalls may be approximately 40 degrees to 80 degrees or 60 degrees to 85 degrees. However, the above values are for illustrative purposes, and are not intended to limit the specific design of the display device  200 C. 
       FIG.  3 A  is a partial cross-sectional view of a display device according to an embodiment of the disclosure. In  FIG.  3 A , a display device  300 A includes a red pixel unit  302 A, a green pixel unit  304 A, a blue pixel unit  306 A, a black matrix  308 A, a substrate  312 A and a substrate  314 A. The red pixel unit  302 A, the green pixel unit  304 A, the blue pixel unit  306 A and the black matrix  308 A are all disposed between the substrate  312 A and the substrate  314 A. The red pixel unit  302 A includes a light emitting element E 302 A, a light conversion element Q 302 A and a color filter C 302 A. The green pixel unit  304 A includes a light emitting element E 304 A, a light conversion element Q 304 A and a color filter C 304 A. The blue pixel unit  306 A includes a light emitting element E 306 A and a filling element F 306 A. In this embodiment, the light emitting element E 302 A, the light emitting element E 304 A and the light emitting element E 306 A are all disposed on the substrate  312 A. Further, the black matrix  308 A, the light conversion element Q 302 A, the color filter C 302 A, the light conversion element Q 304 A, the color filter C 304 A and the filling element F 306 A are all disposed on the substrate  314 A. The substrate  314 A is further disposed with a passivation layer PV 1 A to cover the light conversion element Q 302 A, the color filter C 302 A, the light conversion element Q 304 A, the color filter C 304 A and the filling element F 306 A. Here, the passivation layer PV 1 A may also be used to protect the light conversion elements from moisture and oxygen problems. The substrate  312 A is further disposed with a passivation layer PV 2 A to cover the light emitting element E 302 A, the light emitting element E 304 A and the light emitting element E 306 A. In addition, the substrate  312 A and the substrate  314 A may be attached together through an adhesive layer SLA. The passivation layer PV 1 A and the passivation layer PV 2 A are in contact with opposite surfaces of the adhesive layer SLA. In some embodiments, the passivation layer PV 2 A may include a composite stacked layer PV 2 A 1  and a cover layer PV 2 A 2 . Here, the composite stacked layer PV 2 A 1  is a stacked layer sequentially formed by an organic insulation layer, an organic insulation layer and the like, and the cover layer PV 2 A 2  covers the composite stacked layer PV 2 A 1 . In other embodiments, the passivation layer PV 2 A may be one single layer or may be formed by even more layers stacked together. Here, the passivation layer PV 2 A may also be used to protect the light conversion elements from moisture and oxygen problems. 
     The light emitting element E 302 A includes an active element TA and a light emitting unit ELA. Here, the light emitting unit ELA includes a light emitting layer OLA and two electrodes E 1 A and E 2 A, and the light emitting layer OLA is included between the electrode E 1 A and the electrode E 2 A. The light emitting element E 304 A includes an active element TB and a light emitting unit ELB. Here, the light emitting unit ELB includes a light emitting layer OLB and two electrodes E 1 B and E 2 B, and the light emitting layer OLB is included between the electrode E 1 B and the electrode E 2 B. The light emitting element E 304 A includes an active element TC and a light emitting unit ELC. Here, the light emitting unit ELC includes a light emitting layer OLC and two electrodes E 1 C and E 2 C, and the light emitting layer OLC is included between the electrode E 1 C and the electrode E 2 C. In this embodiment, the electrode E 1 A, the electrode E 1 B and the electrode E 1 C are respectively connected to the active element TA, the active element TB and the active element TC, and are not connected to each other. In other words, the electrode E 1 A, the electrode E 1 B and the electrode E 1 C may be an anode of the organic light emitting element or an anode or a cathode of the micro light emitting element, but not limited thereto. Lights emitted by the light emitting element E 302 A, the light emitting element E 304 A and the light emitting element E 306 A travel on optical paths away from the active element TA, the active element TB and the active element TC towards the substrate  314 A, and a display light of the display device  300 A is emitted to the outside from the substrate  314 A. Therefore, the light emitting element E 302 A, the light emitting element E 304 A and the light emitting element E 306 A are light emitting elements of top emission type. 
     The substrate  312 A is disposed with a pixel defining layer PDL, which surrounds the periphery of the electrode E 1 A, the electrode E 1 B and the electrode E 1 C to separate the electrode E 1 A, the electrode E 1 B and the electrode E 1 C from each other and ensure that the light emitting element E 302 A, the light emitting element E 304 A and the light emitting element E 306 A may emit light independently (i.e., to be formed as sub pixels independent from each other). In addition, the light emitting layer OLA, the light emitting layer OLB and the light emitting layer OLC may comprise a continuous light emitting material OL and are not limited to a single layer. That is to say, the light emitting material layer OL may comprise at least one functional layer. In terms of the connection relationship of the circuits, for example, two or more of the light emitting unit ELA, the light emitting unit ELB and the light emitting unit ELC may be connected in series, but not limited thereto. The purpose of such design is to allow the light emitting elements such as the light emitting unit ELA, the light emitting unit ELB, the light emitting unit ELC to provide a maximum brightness, but not limited thereto. Further, the electrode E 2 A, the electrode E 2 B and the electrode E 2 C may comprise, for example, a continuous electrode material layer EE. The electrode material layer EE may be disposed along the light emitting material layer OL, and the light emitting material layer OL may cover the pixel definition layer PDL. The electrode E 2 A, the electrode E 2 B and the electrode E 2 C may comprise transmissive electrode materials including but not limited to magnesium-silver alloy (MgAg), indium tin oxide (no), zinc oxide (ZnO) and other thin layers so that the lights may be emitted on the optical paths towards the substrate  314 A. In this embodiment, a portion where the light emitting material layer OL contacts the electrode E 1 A may be regarded as the light emitting layer OLA; a portion where the light emitting material layer OL contacts the electrode E 1 B may be regarded as the light emitting layer OLB, and a portion where the light emitting material layer OL contacts the electrode E 1 C may be regarded as the light emitting layer OLC. A material of the light emitting material layer OL comprises an organic light emitting material. In some embodiments, the light emitting material layer OL may comprise multiple layers of materials, such as a hole injection layer, a hole transport layer, an active layer, a charge generation layer, an electron transport layer and an electron injection layer, but not limited thereto. In addition, the substrate  312 A may be further disposed with an auxiliary electrode AE, which is disposed on the pixel defining layer PDL and electrically connected to the electrode material layer EE. In some embodiments, arrangement positions of the pixel definition layer PDL and the auxiliary electrode AE may overlap the black matrix  308 A in a thickness direction of the display device  300 A. The auxiliary electrode AE may improve IR (current-resistance) drop. 
     On the substrate  314 A, the color filter C 302 A is disposed between the substrate  314 A and the light conversion element Q 302 A, and the color filter C 304 A is disposed between the substrate  314 A and the light conversion element Q 304 A. A filtering wavelength of the color filter C 302 A may correspond to a conversion wavelength of the light conversion element Q 302 A, and a filter wavelength of the color filter C 304 A may correspond to a conversion wavelength of the light conversion element Q 304 A. For example, if the light conversion element Q 302 A is adapted to convert the blue light or the ultraviolet light into the red light, the color filter C 302 A is a red filter layer. Further, if the light conversion element Q 304 A is adapted to convert the blue light or the ultraviolet light into the green light, the color filter C 304 A is a green filter layer. In this embodiment, a material of the color filter C 302 A and the color filter C 304 A comprises, for example, a photoresist material, and a material of the light conversion element Q 302 A and the light conversion element Q 304 A comprises: a photoresist material and a quantum dot material dispersed in the photoresist material: an ink material and a quantum dot material dispersed in the ink material; or an inkjet material and a quantum dot material dispersed in the inkjet material, but not limited thereto. The photoresist material of the light conversion element Q 302 A and the light conversion element Q 304 A may comprise a transparent organic material. Accordingly, the color filter C 302 A, the color filter C 304 A, the light conversion element Q 302 A and the light conversion element Q 304 A may be fabricated by a photo lithography or fabricated by an inkjet printing. In addition, the filling element F 306 A may also be fabricated by the photo lithography or fabricated by the inkjet printing, but not limited thereto. In some embodiments, the filling element F 306 A may comprise a transparent material, which has good visible light transmittance to allow the light emitted by the light emitting element E 306 A to penetrate. In addition, scattering particles may be dispersed in the filling element F 306 A, the light conversion element Q 302 A and the light conversion element Q 304 A. Here, a material of scattering particles comprises TiO 2 , but not limited thereto. 
     A layout of the red pixel unit  302 A, the green pixel unit  304 A and the blue pixel unit  306 A may be similar to the description of the foregoing embodiment. In other words, when the display device  300 A is lit, it may be observed under the optical microscope that, a lighting area RB of the red pixel unit  302 A is smaller than a lighting area GB of the green pixel unit  304 B and greater than a lighting area BB of the blue pixel unit  306 A (referring to  FIGS.  1 A,  1 B and  1 C ). 
       FIG.  3 B  is a cross-sectional view of a display device according to another embodiment of the disclosure. Because a display device  300 B of  FIG.  3 B  is substantially the same as the display device  300 A of  FIG.  3 A , the differences between the two embodiments are mainly described below. The display device  300 B includes the red pixel unit  302 A, the green pixel unit  304 A and a blue pixel unit  306 B. The red pixel unit  302 A includes the light emitting element E 302 A, the light conversion element Q 302 A and the color filter C 302 A. The green pixel unit  304 A includes the light emitting element E 304 A, the light conversion element Q 304 A and the color filter C 304 A. The blue pixel unit  306 B includes the light emitting element E 306 A and a filling element F 306 B. In this embodiment, the red pixel unit  302 A and the green pixel unit  304 A are the same as the corresponding elements of the display device  300 A of  FIG.  3 A , and the light emitting element E 306 A of the blue pixel unit  306 B is the same as the corresponding element of the display device  300 A of  FIG.  3 A . Therefore, the same reference numerals are used for these elements in these embodiments. In addition, the black matrix  308 B of the display device  300 B includes a sub matrix  308 B 1  and a sub matrix  308 B 2  disposed on the substrate  314 A, and the filling element F 306 B includes a first filling layer F 306 B 1  and a second filling layer F 306 B 2 . The sub matrix  308 B 1  is used to separate the color filter C 302 A, the color filter C 304 A and the first filling layer F 306 B 1 , and the sub matrix  308 B 2  is used to separate the light conversion element Q 302 A, the light conversion element Q 304 A and the second filling layer F 306 B 2 . In this embodiment, the sub matrix  308 B 1  is located between the sub matrix  308 B 2  and the substrate  314 A, and a width W 308 B 1  of the sub matrix  308 B 1  is greater than a width W 308 B 2  of the sub matrix  308 B 2 . In addition, the sub matrix  308 B 2  may have a trapezoid shape, and the sub matrix  308 B 1  may have a substantially rectangular shape. 
       FIG.  3 C  is a cross-sectional view of a display device according to another embodiment of the disclosure. Because a display device  300 C of  FIG.  3 C  is substantially the same as the display device  300 A of  FIG.  3 A , the differences between the two embodiments are mainly described below. The display device  300 C includes the red pixel unit  302 A, the green pixel unit  304 A and the blue pixel unit  306 A. The red pixel unit  302 A includes the light emitting element E 302 A, the light conversion element Q 302 A and the color filter C 302 A. The green pixel unit  304 A includes the light emitting element E 304 A, the light conversion element Q 304 A and the color filter C 304 A. The blue pixel unit  306 A includes the light emitting element E 306 A and the filling element F 306 A. In this embodiment, the red pixel unit  302 A, the green pixel unit  304 A and the blue pixel unit  306 A are the same as the corresponding elements of the display device  300 A of  FIG.  3 A  Therefore, the same reference numerals are used for these elements in these embodiments. In addition, a black matrix  308 C of the display device  300 C includes a sub matrix  308 C 1  and a sub matrix  308 C 2  disposed on the substrate  314 A. The sub matrix  308 C 1  is used to separate the color filter C 302 A and the color filter C 304 A, and the sub matrix  308 C 2  is used to separate the light conversion element Q 302 A, the light conversion element Q 304 A and the filling element F 306 A. In this embodiment, the sub matrix  308 C 1  is located between the sub matrix  308 C 2  and the substrate  314 A, and a width W 308 C 1  of the sub matrix  308 C 1  is greater than a width W 308 C 2  of the sub matrix  308 C 2 . In addition, both the sub matrix  308 C 2  and the sub matrix  308 C 1  may have a trapezoid shape. Furthermore, a height (thickness) H 308 C 2  of the sub matrix  308 C 2  may be aligned with or even greater than a height HQ 302 A (thickness) of the light conversion element Q 302 A and a height HQ 304 A (thickness) of the light conversion element Q 304 A. In some embodiments, an inkjet device may be used to drop a light conversion material into a groove defined by the sub matrix  308 C 2  on the substrate  314 A, and then the light conversion material is cured to form the light conversion element Q 302 A and the light conversion element Q 304 A. Since the sub matrix  308 C 2  has a sufficient height, during the inkjet printing, the droplets of the light conversion material will not overflow and thus contamination between different light conversion materials may be reduced. In addition, in this embodiment, the color filter C 302 A, the color filter C 304 A and the filling element F 306 A may also be fabricated in an opening defined by the sub matrix  308 C 1  by the inkjet printing. 
       FIG.  3 D  is a cross-sectional view of a display device according to another embodiment of the disclosure. Because a display device  300 D of  FIG.  3 D  is substantially the same as the display device  300 A of  FIG.  3 A , the differences between the two embodiments are mainly described below. The display device  300 D includes a red pixel unit  302 D, a green pixel unit  304 D and the blue pixel unit  306 A. The red pixel unit  302 D includes the light emitting element E 302 A, the light conversion element Q 302 A and a color filter C 302 D. The green pixel unit  304 D includes the light emitting element E 304 A, the light conversion element Q 304 A and a color filter C 304 D. The blue pixel unit  306 A includes the light emitting element E 306 A and the filling element F 306 A. In this embodiment, the light emitting element E 302 A and the light conversion element Q 302 A of the red pixel unit  302 D, the light emitting element E 304 A and the light conversion element Q 304 A of the green pixel unit  304 D and the entire blue pixel unit  306 A are all the same as the corresponding elements of the display device  300 A of  FIG.  3 A  Therefore, the same reference numbers are used. In addition, when fabricating the color filter C 302 D, a peripheral portion PA 1  is fabricated using the same material; when fabricating the color filter C 304 D, a peripheral portion PA 2  is fabricated using the same material. Here, a black matrix  308 D of the display device  300 D is formed by stacking the peripheral portion PA 1  and the peripheral portion PA 2  together. That is to say, a material of the black matrix  308 D may be the same as those of the color filter C 302 D and the color filter C 304 D. 
       FIG.  3 E  is a cross-sectional view of a display device according to another embodiment of the disclosure. Because a display device  300 E of  FIG.  3 E  is substantially the same as the display device  300 D of  FIG.  3 D , the differences between the two embodiments are mainly described below. The display device  300 E includes the red pixel unit  302 D, the green pixel unit  304 D and the blue pixel unit  306 A. The red pixel unit  302 D includes the light emitting element E 302 A, the light conversion element Q 302 A and the color filter C 302 D. The green pixel unit  304 D includes the light emitting element E 304 A, the light conversion element Q 304 A and the color filter C 304 D. The blue pixel unit  306 A includes the light emitting element E 306 A and the filling element F 306 A. In this embodiment, the red pixel unit  302 D and the green pixel unit  304 D are the same as the corresponding elements of the display device  300 D of  FIG.  3 D , and the blue pixel unit  306 A is the same as the corresponding element of the display device  300 A of  FIG.  3 A . Therefore, the same reference numerals are used for these elements in these embodiments. In addition, a black matrix  308 E of the display device  300 E includes a sub matrix  308 E 1  and a sub matrix  308 E 2  disposed on the substrate  314 A. The sub matrix  308 E 1  is used to separate the color filter C 302 D and the color filter C 304 D, and the sub matrix  308 E 2  is used to separate the light conversion element Q 302 A and the light conversion element Q 304 A. In this embodiment, the sub matrix  308 E 1  is located between the sub matrix  308 E 2  and the substrate  314 A. While fabricating the color filter C 302 D and the color filter C 304 D, the peripheral portion PA 1  and the peripheral portion PA 2  may also be fabricated, and the peripheral portion PA 1  and the peripheral portion PA 2  may be stacked together to form the sub matrix  308 E 1 . That is to say, the sub matrix  308 E 1  is substantially the same as the stack of the black matrix  308 D in  FIG.  3 D . 
       FIG.  3 F  is a cross-sectional view of a display device according to another embodiment of the disclosure. A display device  300 F includes the red pixel unit  302 D, the green pixel unit  304 D and the blue pixel unit  306 A. The red pixel unit  302 D includes the light emitting element E 302 A, the light conversion element Q 302 A and the color filter C 302 D. The green pixel unit  304 D includes the light emitting element E 304 A, the light conversion element Q 304 A and the color filter C 304 D. The blue pixel unit  306 A includes the light emitting element E 306 A and the filling element F 306 A. In this embodiment, the red pixel unit  302 D and the green pixel unit  304 D are the same as the corresponding elements of the display device  300 D of  FIG.  3 D , and the blue pixel unit  306 A is the same as the corresponding element of the display device  300 A of  FIG.  3 A . Therefore, the same reference numerals are used for these elements in these embodiments. In addition, a black matrix  308 F includes the peripheral portion PA 1 , the peripheral portion PA 2 , and a light shielding material BM. When fabricating the color filter C 302 D and the color filter C 304 D of the display device  300 F, the peripheral portion PA 1  and the peripheral portion PA 2  may be simultaneously fabricated. In addition, the light shielding material BM is located on the peripheral portion PA 1  and penetrates the peripheral portion PA 2 , for example. In this embodiment, a height of the black matrix  308 F is greater than a height of the light conversion element Q 302 A and a height of the light conversion element Q 304 A, for example. In addition, the light conversion element Q 302 A and the light conversion element Q 304 A may be fabricated by the inkjet printing, but not limited thereto. In some embodiments, the light conversion element Q 302 A and the light conversion element Q 304 A may be fabricated by the photo lithography. 
       FIG.  3 G  is a cross-sectional view of a display device according to another embodiment of the disclosure. Because a display device  300 G of  FIG.  3 G  is substantially the same as the display device  300 A of  FIG.  3 A , the differences between the two embodiments are mainly described below. The display device  300 G includes a red pixel unit  302 G, a green pixel unit  304 G and a blue pixel unit  306 G. The red pixel unit  302 G includes the light emitting element E 302 A, the light conversion element Q 302 A and a color filter C 302 G. The green pixel unit  304 G includes the light emitting element E 304 A, the light conversion element Q 304 A and a color filter C 304 G. The blue pixel unit  306 G includes the light emitting element E 306 A and a filling element F 306 G. In this embodiment, the light emitting element E 302 A and the light conversion element Q 302 A of the red pixel unit  302 G, the light emitting element E 304 A and the light conversion element Q 304 A of the green pixel unit  304 G and the light emitting element E 306 A of the blue pixel unit  306 G are all the same as the corresponding elements of the display device  300 A of  FIG.  3 A . Therefore, the same reference numerals are used for these elements in these embodiments. In addition, the black matrix is not provided on the substrate  314 A of the display device  300 G. The color filter C 302 G, the color filter C 304 G and the filling element F 306 G of the display device  300 G are arranged side by side without overlapping one another. In addition, the light conversion element Q 302 A and the light conversion element Q 304 A may be fabricated by the photo lithography and independently disposed on the color filter C 302 G and the color filter C 304 G. 
       FIG.  4 A  is a partial cross-sectional view of a display device according to an embodiment of the disclosure. In  FIG.  4 A , a display device  400 A includes a red pixel unit  402 A, a green pixel unit  404 A, a blue pixel unit  406 A, a black matrix  408 A and a substrate  412 A. The red pixel unit  402 A, the green pixel unit  404 A, the blue pixel unit  406 A and the black matrix  408 A are all disposed on the substrate  412 A. That is to say, the display device  400 A may be a single substrate device. The red pixel unit  402 A includes a light emitting element E 402 A, a light conversion element Q 402 A and a color filter C 402 A. The green pixel unit  404 A includes a light emitting element E 404 A, a light conversion element Q 404 A and a color filter C 404 A. The blue pixel unit  406 A includes a light emitting element E 406 A and a filling element F 406 A. The substrate  412 A is further disposed with a passivation layer PV 3  to cover the light emitting element E 402 , the light emitting element E 404 A and the light emitting element E 406 A. The substrate  412 A is further disposed with a passivation layer PV 4 A and a passivation layer PVSA to cover the light conversion element Q 402 A, the color filter C 402 A, the light conversion element Q 404 A, the color filter C 404 A and the filling element F 406 A. 
     The light emitting element E 402 A includes the active element TA and the light emitting unit ELA. Here, the light emitting unit ELA includes the light emitting layer OLA and the two electrodes E 1 A and E 2 A, and the light emitting layer OLA is included between the electrode E 1 A and the electrode E 2 A. The light emitting element E 404 A includes the active element TB and the light emitting unit ELB. Here, the light emitting unit ELB includes the light emitting layer OLB and the two electrodes E 1 B and E 2 B, and the light emitting layer OLB is included between the electrode E 1 B and the electrode E 2 B. The light emitting element E 406 A includes the active element TC and the light emitting unit ELC. Here, the light emitting unit ELC includes the light emitting layer OLC and the two electrodes E 1 C and E 2 C, and the light emitting layer OLC is included between the electrode E 1 C and the electrode E 2 C. In this embodiment, the electrode E 1 A, the electrode E 1 B and the electrode E 1 C are respectively connected to the active element TA, the active element TB and the active element TC, and are not connected to each other. Lights emitted by each of the light emitting element E 402 A, the light emitting element E 404 A, and the light emitting element E 406 A are emitted away from the active element TA, the active element TB and the active element TC, and a display light of the display device  400 A is emitted from the passivation layer PVSA. Therefore, the light emitting element E 402 A, the light emitting element E 404 A and the light emitting element E 406 A are light emitting elements of top emission type. 
     The substrate  412 A is disposed with the pixel defining layer PDL, which surrounds the periphery of the electrode E 1 A, the electrode E 1 B and the electrode E 1 C to separate the electrode E 1 A, the electrode E 1 B and the electrode E 1 C from each other and ensure that the light emitting element E 402 A, the light emitting element E 404 A and the light emitting element E 406 A can operate (e.g., emit light) independently. In addition, the light emitting layer OLA, the light emitting layer OLB and the light emitting layer OLC may be formed by the continuous light emitting material OL, and the electrode E 2 A, the electrode E 2 B and the electrode E 2 C may be formed by, for example, the continuous electrode material layer EE. The electrode material layer EE may be disposed along the light emitting material layer OL, and the light emitting material layer OL may cover the pixel definition layer PDL. A material of the light emitting material layer OL comprises an organic light emitting material. In some embodiments, the light emitting material layer OL may comprise multiple layers of materials, such as the hole injection layer, the hole transport layer, the active layer, the electron transport layer and the electron injection layer, but not limited thereto. In some embodiments, an arrangement position of the pixel definition layer PDL may overlap the black matrix  408 A in a thickness direction of the display device  400 A. 
     The color filter C 402 A is disposed between the passivation layer PV 4 A and the light conversion element Q 402 A, and the color filter C 404 A is disposed between the passivation layer PV 4 A and the light conversion element Q 404 A. A filtering wavelength of the color filter C 402 A may correspond to a conversion wavelength of the light conversion element Q 402 A, and a filter wavelength of the color filter C 404 A may correspond to a conversion wavelength of the light conversion element Q 404 A. For example, if the light conversion element Q 402 A is adapted to convert the blue light or the ultraviolet light into the red light, the color filter C 402 A is a red filter layer that allows the red light to pass through. In addition, if the light conversion element Q 404 A is adapted to convert the blue light or the ultraviolet light into the green light, the color filter C 404 A is a green filter layer that allows the green light to pass through. A layout of the red pixel unit  402 A, the green pixel unit  404 A and the blue pixel unit  406 A may be similar to the description of the foregoing embodiment. In other words, when the display device  400 A is lit, it may be observed under the optical microscope that, a lighting area of the red pixel unit  402 A is smaller than a lighting area of the green pixel unit  404 A and greater than a lighting area of the blue pixel unit  406 A. 
     The black matrix  408 A of the display device  400 A include a sub matrix  408 A 1  and a sub matrix  408 A 2  disposed on the substrate  412 A, and the sub matrix  408 A 1  and the sub matrix  408 A 2  are stacked together. The sub matrix  408 A 1  is used to separate the color filter C 402 A and the color filter C 404 A, and the sub matrix  408 A 2  is used to separate the light conversion element Q 402 A and the light conversion element Q 404 A. In addition, the filling element F 406 A may directly contact both the sub matrix  408 A 1  and the sub matrix  408 A 2 . In this embodiment, the sub matrix  408 A 1  is disposed between the sub matrix  408 A 2  and the passivation layer PV 4 A. In some embodiments, the sub matrix  408 A 2  may be fabricated on the substrate  412 A, and the sub matrix  408 A 1  may be fabricated on the sub matrix  408 A 2 . Further, a width of the sub matrix  408 A 2  may be greater than a width of the sub matrix  408 A 1 , but not limited thereto. In addition, the sub matrix  408 A 2  may have a trapezoid shape which is gradually reduced away from the substrate  412 A, and the sub matrix  408 A 1  may have a substantially rectangular shape. In some embodiments, a thickness of one of the sub matrix  408 A 1  and the sub matrix  408 A 2  may be greater than that of the light conversion element Q 402 A, the light conversion element Q 404 A and the filling element F 406 A, while the other one is not, but not limited thereto. 
     In some embodiments, a material of the color filter C 402 A and the color filter C 404 A comprises, for example, a photoresist material, and a material of the light conversion element Q 402 A and the light conversion element Q 404 A comprises a photoresist material and a quantum dot material dispersed in the photoresist material. Accordingly, the color filter C 402 A, the color filter C 404 A, the light conversion element Q 402 A and the light conversion element Q 404 A may be fabricated by the photo lithography. In addition, the filling element F 406 A may also be fabricated by the photo lithography or the inkjet, but not limited thereto. In some embodiments, the filling element F 406 A may comprise a transparent material, which has good visible light transmittance to allow the light emitted by the light emitting element E 406 A to penetrate. In an alternative embodiment, the filling element F 406 A may be a blue filter, but not limited thereto. In addition, the filling element F 406 A, the light conversion element Q 402 A and the light conversion element Q 404 A may be dispersed with scattering particles. Here, a material of scattering particles comprises TiO 2 , but not limited thereto. 
     In some other embodiments, the light conversion element Q 402 A and the light conversion element Q 404 A may be fabricated by the inkjet printing. In some embodiments, after the sub matrix  408 A 2  is fabricated on the substrate  412 A, an inkjet device may be used to drop a light conversion material into a groove defined by the sub matrix  408 A 2  on the substrate  412 A, and then the light conversion material is cured to form the light conversion element Q 402 A and the light conversion element Q 404 A. The sub matrix  408 A 2  protrudes away from the substrate  412 A by a surface of the passivation layer PV 3 A. Accordingly, during the inkjet printing, the droplets of the light conversion material will not overflow and thus mixing between different light conversion materials may be reduced. After the light conversion material is cured to form the light conversion element Q 402 A and the light conversion element Q 404 A, the sub matrix  408 A 1  may be fabricated on the sub matrix  408 A 2 . Then, the inkjet device may be used to drop a color filter material into a groove defined by the sub matrix  408 A 1  on the substrate  412 A, and drop a filling material into a groove defined by the sub matrix  408 A 1  and the sub matrix  408 A 2  on the substrate  412 A. Then, after the color liter material and the filling material are cured, the color filter C 402 A, the color filter C 404 A and the filter element F 406 A may be formed. In some embodiments, a top surface T 408 A of the sub matrix  408 A 1  may be farther away from the substrate  412 A than a top surface T 402 A of the color filter C 402 A, a top surface T 404 A of the color filter C 404 A and a top surface T 406 A of the filling element F 406 A. Alternatively, any two or a plurality or all of the top surface T 408 A of the sub matrix  408 A 1 , the top surface T 402 A of the color filter C 402 A, the top surface T 404 A of the color filter C 404 A and the top surface T 406 A of the filling element F 406 A may be coplanar. In some embodiments, a top surface of the sub matrix  408 A 2  from the substrate  412 A may be farther away from the substrate  412 A than a top surface of the light conversion element Q 402 A from the substrate  412 A, and may also be farther away from the substrate  412 A than a top surface of the light conversion element Q 404 A from the substrate  412 A. In addition, top surfaces of the light conversion element Q 402 A and the light conversion element Q 404 A may be at different distances away from the substrate  412 A. Among the top surface of the light conversion element Q 402 A and the top surface of the light conversion element Q 404 A, the top surface farther from the substrate  412 A may be closer to the substrate  412 A than the top surface of the sub matrix  408 A 2  from the substrate  412 A. 
       FIG.  4 B  is a cross-sectional view of a display device according to another embodiment of the disclosure. Because a display device  400 B of  FIG.  4 B  is substantially the same as the display device  400 A of  FIG.  4 A , the differences between the two embodiments are mainly described below. In  FIG.  4 B , a display device  400 B includes the red pixel unit  402 A, the green pixel unit  404 A and the blue pixel unit  406 A. The red pixel unit  402 A includes the light emitting element E 402 A, the light conversion element Q 402 A and the color filter C 402 A. The green pixel unit  404 A includes the light emitting element E 404 A, the light conversion element Q 404 A and the color filter C 404 A. The blue pixel unit  406 A includes the light emitting element E 406 A and the filling element F 406 A. In addition, a black matrix  408 B of the display device  400 B includes a sub matrix  408 B 1 , a sub matrix  408 B 2  and a sub matrix  408 B 3  sequentially stacked on the substrate  412 A. When fabricating the display device  400 B, the sub matrix  408 B 1  may first be fabricated on the passivation layer PV 3 A by the photo lithography. Then, the light conversion element Q 402 A, the light conversion element Q 404 A and a first filling layer F 406 A 1  of the filling element F 406 A may be fabricated in an opening defined by the sub matrix  408 B 1 . Here, the light conversion element Q 402 A, the light conversion element Q 404 A and the first filling layer F 406 A 1  are spaced apart from each other. In some embodiments, the light conversion element Q 402 A, the light conversion element Q 404 A and the first filling layer F 406 A 1  may overlap each other at a position where the black matrix  408 B is located. Then, the sub matrix  408 B 2  is fabricated on the sub matrix  408 B 1 , and the sub matrix  408 B 2  includes a matrix portion SM 1  and a matrix portion SM 2  sequentially stacked on the sub matrix  408 B 1 . The matrix portion SM 1  of the sub matrix  408 B 2  is filled in a gap between the light conversion element Q 402 A, the light conversion element Q 404 A and the first filling layer F 406 A 1 . The matrix portion SM 2  of the sub matrix  408 B 2  forms a structure that protrudes away from the substrate  412 A relative to the light conversion element Q 402 A, the light conversion element Q 404 A and the first filling layer F 406 A 1 . Next, the color filter C 402 A, the color filter C 404 A and a second filling layer F 406 A 2  of the filling element F 406 A are fabricated in an opening defined by the matrix portion SM 2  of the sub matrix  408 B 2 . Then, the sub matrix  408 B 3  is fabricated on the  408 B 2  so that the sub matrix  408 B 3  is filled between the color filter C 402 A, the color filter C 404 A and the second filling layer F 406 A 2 . However, in other embodiments, the second filling layer F 406 A 2  may also be omitted. In some embodiments, the sub matrix  408 B 1  and the matrix portion SM 2  may have a trapezoid shape narrower in direction farther away from the substrate  412 A. The sub matrix  408 B 3  and the matrix portion SM 1  may have a trapezoid shape wider in direction farther away from the substrate  412 A, but not limited thereto. Further, in some embodiments, the sub matrix  408 B 1 , the sub matrix  408 B 2  and the sub matrix  408 B 3  may be fabricated on the substrate  412 A by the photo lithography. 
       FIG.  4 C  is a cross-sectional view of a display device according to another embodiment of the disclosure. Because a display device  400 C of  FIG.  4 C  is substantially the same as the display device  400 A of  FIG.  4 A , the differences between the two embodiments are mainly described below. The display device  400 C of  FIG.  4 C  includes a red pixel unit  402 C, a green pixel unit  404 C and the blue pixel unit  406 A. The red pixel unit  402 C includes the light emitting element E 402 A, the light conversion element Q 402 A and a color filter C 402 C. The green pixel unit  404 C includes the light emitting element E 404 A, the light conversion element Q 404 A and a color filter C 404 C. The blue pixel unit  406 A includes the light emitting element E 406 A and the filling element F 406 A. In addition, a black matrix  408 C of the display device  400 C includes the sub matrix  408 C 1  and a sub matrix  408 C 2 . The sub matrix  408 C 1  is similar to the sub matrix  408 B 1  in  FIG.  4 B , which is disposed on the passivation layer PV 3 A and is located between the light conversion element Q 402 A, the light conversion element Q 404 A and the first filling layer F 406 A 1  of the filling element F 406 A. In addition, when fabricating the color filter C 402 C, the peripheral portion PA 1  is fabricated using the same material; and when fabricating the color filter C 404 C, the peripheral portion PA 2  is fabricated using the same material. Here, the sub matrix  408 C 2  is formed by stacking the peripheral portion PA 1  and the peripheral portion PA 2  together. That is to say, a material of the  408 C 2  may be the same as those of the color filter C 402 C and the color filter C 404 C. In some embodiments, the peripheral portion PA 2  may be filled in a gap between the light conversion element Q 402 A, the light conversion element Q 404 A and the first filling layer F 406 A 1 , but not limited thereto. 
       FIG.  4 D  is a cross-sectional view of a display device according to another embodiment of the disclosure. Because a display device  400 D of  FIG.  4 D  is substantially the same as the display device  400 A of  FIG.  4 A , the differences between the two embodiments are mainly described below. The display device  400 D of  FIG.  4 D  includes a red pixel unit  402 D, the green pixel unit  404 A and the blue pixel unit  406 A. The red pixel unit  402 D includes the light emitting element E 402 A, the light conversion element Q 402 A and a color filter C 402 D. The green pixel unit  404 A includes the light emitting element E 404 A, the light conversion element Q 404 A and the color filter C 404 A. The blue pixel unit  406 A includes the light emitting element E 406 A and the filling element F 406 A. In addition, a black matrix  408 D of the display device  400 D includes the sub matrix  408 B 2 , and the peripheral portion PAL Here, the sub matrix  408 B 2  is substantially the same as the sub matrix  408 B 2  in  FIG.  4 B , and the peripheral portion PA 1  is substantially the same as the peripheral portion PA 1  in  FIG.  4 C . Specifically, the sub matrix  408 B 2  is disposed on the passivation layer PV 3 A; the peripheral portion PA 1  is stacked on the sub matrix  408 B 2 . When fabricating the color filter C 402 D, the peripheral portion PA 1  is fabricated using the same material, and the color filter C 404 A and the second filling layer F 406 A 2  of the filling element F 406 A may directly contact the peripheral portion PA 1  The sub matrix  408 B 2  includes the matrix portion SM 1  and the matrix portion SM 2 . Here, the matrix portion SM 1  is filled in the gap between the light conversion element Q 402 A, the light conversion element Q 404 A and the first filling layer F 406 A 1 . The matrix portion SM 2  forms a structure that protrudes away from the substrate  412 A relative to the light conversion element Q 402 A, the light conversion element Q 404 A and the first filling layer F 406 A 1  of the filling element F 406 A. 
       FIG.  4 E  is a cross-sectional view of a display device according to another embodiment of the disclosure. Because a display device  400 E of  FIG.  4 E  is substantially the same as the display device  400 A of  FIG.  4 A , the differences between the two embodiments are mainly described below. The display device  400 E of  FIG.  4 E  includes a red pixel unit  402 E, a green pixel unit  404 E and a blue pixel unit  406 E. The red pixel unit  402 E includes the light emitting element E 402 A, a light conversion element Q 402 E and a color filter C 402 E. The green pixel unit  404 E includes the light emitting element E 404 A, a light conversion element Q 404 E and a color filter C 404 E. The blue pixel unit  406 E includes the light emitting element E 406 A and a filling element F 406 E. The specific structures and designs of the light emitting element E 402 A, the light emitting element E 404 A and the light emitting element E 406 A are substantially the same as those in the embodiment of  FIG.  4 A , which will not be repeated hereinafter. In this embodiment, because the display device  400 E does not include the black matrix, the light conversion element Q 402 E, the light conversion element Q 404 E and a first filling layer F 406 E 1  of the filling element F 406 E are disposed adjacent to each other. The color filter C 402 E is stacked on the light conversion element Q 402 E; the color filter C 404 E is stacked on the light conversion element Q 404 E; and a second filling layer F 406 E 2  of the filling element F 406 E is stacked on the first filling layer F 406 E 1 . The color filter C 402 E, the light conversion element Q 402 E, the color filter C 404 E, the light conversion element Q 404 E and the filling element F 406 E may be fabricated by, for example, the photo lithography. Therefore, even though the display device  400 E does not include the black matrix, the materials of the light conversion element Q 402 E and the light conversion element Q 404 E will not mix with each other, and the materials of the color filter C 402 E and the color filter C 404 E will not mix with each other either. In some embodiments, a space between the materials of the color filter C 402 E, the light conversion element Q 402 E, the color filter C 404 E and the light conversion element Q 404 E and the filling element F 406 E may be filled by a filler FM. In addition, the materials of the color filter C 402 E, the light conversion element Q 402 E, the color filter C 404 E and the light conversion element Q 404 E will not contaminate with the material of the filling element F 406 E. 
       FIG.  4 F  is a cross-sectional view of a display device according to another embodiment of the disclosure. Because a display device  400 F of  FIG.  4 F  is substantially the same as the display device  400 A of  FIG.  4 A , the differences between the two embodiments are mainly described below. The display device  400 F of  FIG.  4 F  includes a red pixel unit  402 F, a green pixel unit  404 F and the blue pixel unit  406 A. The red pixel unit  402 F includes the light emitting element E 402 A, the light conversion element Q 402 A and a color filter C 402 F. The green pixel unit  404 F includes the light emitting element E 404 A, the light conversion element Q 404 A and a color filter C 404 F. The blue pixel unit  406 A includes the light emitting element E 406 A and the filling element F 406 A. The specific structures and designs of the light conversion element Q 402 A, the light conversion element Q 404 A, the light emitting element E 402 A, the light emitting element E 404 A, the light emitting element E 406 A and the filling element F 406 A are substantially the same as those in the embodiment of  FIG.  4 A , which will not be repeated hereinafter. In addition, the display device  400 F further includes a black matrix  408 F, and the structural design of the black matrix  408 F is substantially the same as the sub matrix  408 A 1  of  FIG.  4 A . 
     In this embodiment, the light conversion element Q 402 A, the light conversion element Q 404 A and the first filling layer F 406 A 1  of the filling element F 406 A may be spaced apart by the black matrix  408 F, and the color filter C 402 F, and the color filter C 404 F and the second filling layer F 406 A 2  of the filling element F 406 A may be disposed adjacent to each other. That is to say, the color filter C 402 F, the color filter C 404 F and the second filling layer F 406 A 2  of the filling element F 406 A are in contact with each other on sidewalls. In addition, boundaries between the color filter C 402 F, the color filter C 404 F and the second filling layer F 406 A 2  of the filling element F 406 A are located on the black matrix  408 F, for example. In some embodiments, the boundaries between the color filter C 402 F, the color filter C 404 F and the second filling layer F 406 A 2  of the filling element F 406 A are oblique boundaries, which are inclined relative to a normal direction of the substrate  412 A. In some embodiments, a boundary B 1  between the color filter C 402 F and the color filter C 404 F inclined closer to a center of the color filter C 402 F in direction farther away from the substrate  412 A, and a boundary B 2  between the color filter C 404 F and the second filling layer F 406 A 2  inclined closer to a center of the second filling layer F 406 A 2  in direction farther away from the substrate  412 A. Accordingly, the green pixel unit  404 F and the color filter C 404 F have a trapezoid shape wider in direction farther away from the substrate  412 A, but not limited thereto. 
       FIG.  5 A  is a partial cross-sectional view of a display device according to another embodiment of the disclosure. A display device  500 A includes a red pixel unit  502 A, a green pixel unit  504 A, a blue pixel unit  506 A and a black matrix  508 A. The red pixel unit  502 A, the green pixel unit  504 A, the blue pixel unit  506 A and the black matrix  508 A are all disposed between a substrate  512 A and a substrate  514 A. The red pixel unit  502 A includes a light emitting element E 502 A, a light conversion element Q 502 A and a color filter C 502 A. The light conversion element Q 502 A is disposed between the light emitting element E 502 A and the color filter C 502 A. The green pixel unit  504 A includes a light emitting element E 504 A, a light conversion element Q 504 A and a color filter C 504 A. The light conversion element Q 504 A is disposed between the light emitting element E 504 A and the color filter C 504 A. The blue pixel unit  506 A includes a light emitting element E 506 A and a filling element F 506 A. The filling element F 506 A is disposed between the light emitting element E 502 A and the substrate  512 A. In  FIG.  5 A , the display device  500 A may further include a passivation layer PV 6 A and a passivation layer PV 7 A. The light emitting element E 502 A, the light emitting element E 504 A and the light emitting element E 506 A are disposed between the passivation layer PV 6 A and the substrate  514 A. The light conversion element Q 502 A, the light conversion element Q 504 A, the color filter C 502 A, the color filter C 504 A and the filling element F 506 A are disposed between the passivation layer PV 7 A and the passivation layer PV 6 A. In addition, the passivation layer PV 7  may contact the substrate  512 A, but not limited thereto. 
     The light emitting element E 502 A includes the active element TA and the light emitting unit ELA. The light emitting element E 504 A includes the active element TB and the light emitting unit ELB. The light emitting element E 506 A includes the active element TC and the light emitting unit ELC. The specific structures and designs of the active element TA, the active element TB, the active element TC, the light emitting unit ELA, the light emitting unit ELB and the light emitting unit ELC are substantially the same as those in the embodiment of  FIG.  3 A , which will not be repeated hereinafter. Similar to the embodiment of  FIG.  3 A  described above, the light emitting unit ELA, the light emitting unit ELB and the light emitting unit ELC may be spaced apart by the pixel defining layer PDL. 
     In this embodiment, lights emitted by the light emitting element E 502 A, the light emitting element E 504 A and the light emitting element E 506 A are, for example, emitted away from the substrate  514 A towards the active elements TA, TB and TC. In other words, a light displayed by the display device  500 A is emitted from the substrate  512 A. The light emitting element E 502 A, the light emitting element E 504 A and the light emitting element E 506 A are, for example, designed to be bottom emission type. In this embodiment, the electrode material layer EE of the light emitting element E 502 A, the light emitting element E 504 A, and the light emitting element E 506 A may be, for example, a metal layer, which may fill in an uneven structure formed by the pixel definition layer PDL, for example. In some embodiments, the electrode material layer EE may be a metal layer with a thickness thicker than those of the electrode E 1 A, the electrode E 1 B and the electrode E 1 C (marked in  FIG.  3 A ), or a metal layer with a resistivity higher than those of the electrode E 1 A, the electrode E 1 B and the electrode E 1 C (marked in  FIG.  3 A ). The electrode material layer EE may contact the substrate  514 A. However, in other embodiments, a buffer layer may be further provided between the electrode material layer EE and the substrate  514 A to improve an adhesion of the electrode material layer EE and the substrate  514 A. In some embodiments, the electrode material layer EE may have a light reflection property and is suitable for reflecting the lights emitted by the light emitting element E 502 A, the light emitting element E 504 A and the light emitting element E 506 A to be towards the substrate  512 A, but not limited thereto. 
     The black matrix  508 A of the display device  500 A includes a sub matrix  508 A 1 , a sub matrix  508 A 2  and a sub matrix  508 A 3  sequentially stacked on the substrate  512 A. When fabricating the display device  500 A, the sub matrix  508 A 1  may first be fabricated by the photo lithography. Then, the color filter C 502 A, the color filter C 504 A and a first filling layer F 506 A 1  of the filling element F 506 A may be fabricated in an opening defined by the sub matrix  508 A 1 . Here, the sub matrix  508 A 1  spaces apart the color filter C 502 A, the color filter C 504 A and the first filling layer F 506 A from each other. Then, the sub matrix  508 A 2  is fabricated on the sub matrix  508 A 1 , and the sub matrix  508 A 2  includes the matrix portion SM 1  and the matrix portion SM 2  sequentially stacked on the matrix  508 A 1 . The matrix portion SM 1  of the sub matrix  508 A 2  is filled in a gap between the color filter C 502 A, the color filter C 504 A and the first filling layer F 506 A. The matrix portion SM 2  of the sub matrix  508 A 2  forms a structure that protrudes away from the substrate  512 A relative to the color filter C 502 A, the light color filter C 504 A and the first filling layer F 506 A 1 . Next, the light conversion element Q 502 A, the light conversion element Q 504 A and a second filling layer F 506 A 2  of the filling element F 506 A are fabricated in an opening defined by the matrix portion SM 2  of the sub matrix  508 A 2 . Then, the sub matrix  508 A 3  is fabricated on the  508 A 2  so that the sub matrix  508 A 3  is filled between the light conversion element Q 502 A, the light conversion element Q 504 A and the second filling layer F 506 A 2 . In some embodiments, the sub matrix  508 A 1  and the matrix portion SM 2  may have a trapezoid shape narrower in direction farther away from the substrate  512 A. The sub matrix  508 A 3  and the matrix portion SM 1  may have a trapezoid shape wider in direction farther away from the substrate  512 A, but not limited thereto. Further, in some embodiments, the sub matrix  508 A 1 , the sub matrix  508 A 2  and the sub matrix  508 A 3  may be fabricated on the substrate  512 A by the photo lithography. 
       FIG.  5 B  is a partial cross-sectional view of a display device according to another embodiment of the disclosure. Because a display device  500 B of  FIG.  5 B  is substantially the same as the display device  500 A of  FIG.  5 A , the difference between the two embodiments is mainly an arrangement position of a substrate  514 B. The display device  500 B includes the red pixel unit  502 A, the green pixel unit  504 A and a blue pixel unit  506 A. The red pixel unit  502 A includes the light emitting element E 502 A, the color filter C 502 A and the light conversion element Q 502 A. The green pixel unit  504 A includes the light emitting element E 504 A, the color filter C 504 A and the light conversion element Q 504 A. The blue pixel unit  506 A includes the light emitting element E 506 A and the filling element F 506 A. In the display device  500 B, because the substrate  514 B is used to replace the passivation layer PV 6 A in  FIG.  5 A , the display device  500 B does not have the passivation layer PV 6 A. 
     The light emitting element E 502 A of the red pixel unit  502 A, the light emitting element E 504 A of the green pixel unit  504 A and the light emitting element E 506 A of the blue pixel unit  506 A may be disposed on a first side of the substrate  514 B. The light conversion element Q 502 A and the color filter C 502 A of the red pixel unit  502 A, the light conversion element Q 504 A and the color filter C 504 A of the green pixel unit  504 A and the light conversion element Q 506 A and the color filter C 506 A of the blue pixel unit  506 A are disposed on a second side of the substrate  514 B. The first side and the second side are opposite sides. In addition, the light emitting element E 502 A, the light emitting element E 504 A and the light emitting element E 506 A may share the electrode material layer EE, and the electrode material layer EE is provided as an outermost component of the display device  500 B without being covered by the substrate. In some embodiments, the electrode material layer EE may be covered by another substrate, as shown by  FIG.  5 A . 
       FIG.  5 C  is a cross-sectional view of a display device according to another embodiment of the disclosure. Because a display device  500 C of  FIG.  5 C  is substantially the same as the display device  500 A of  FIG.  5 A , the differences between the two embodiments are mainly described below. The display device  500 C includes the red pixel unit  502 A, the green pixel unit  504 A and the blue pixel unit  506 A. The red pixel unit  502 A includes the light emitting element E 502 A, the color filter C 502 A and the light conversion element Q 502 A. The green pixel unit  504 A includes the light emitting element E 504 A, the color filter C 504 A and the light conversion element Q 504 A. The blue pixel unit  506 A includes the light emitting element E 506 A and the filling element F 506 A. The red pixel unit  502 A, the green pixel unit  504 A and the blue pixel unit  506 A are all disposed between the substrate  512 A and the substrate  514 A. Further, a height of a black matrix  508 C protruding away from the substrate  512 A by the passivation layer PV 7  is greater so that the color filter C 502 A stacked with the light conversion element Q 502 A does not exceed the height of the black matrix  508 C. Meanwhile, the color filter C 504 A stacked with the light conversion element Q 504 A does not exceed the height of the black matrix  508 C, and the filling element F 506  does not exceed the height of the black matrix  508 C either. 
     In some embodiments, after the black matrix  508 C is fabricated on the substrate  512 A, a plurality of groove structures may be formed on the substrate  512 A. The color filter C 502 A, the color filter C 504 A and the first filling layer F 506 A 1  of the filling element F 506 A may be formed on the passivation layer PV 7 A by the inkjet printing. Because the height of the black matrix  508 C is high, the droplets used during the inkjet printing are not prone to spill over and thus mixing between different materials may be prevented. After inkjet droplets are cured in the corresponding grooves to form the color filter C 502 A, the color filter C 504 A and the first filling layer F 506 A 1  of the filling element F 506 A, the light conversion element Q 502 A, the light conversion element Q 504  and the second filling layer F 506 A 2  of the filling element F 506 A may be respectively formed on the color filter C 502 A, the color filter C 504 A and the first filling layer F 506 A 1  of the filling element F 506 A by the inkjet printing. In other embodiments, the filling element F 506 A may be fabricated by using one single inkjet printing. Accordingly, the filling element F 506 A may be a single film layer without being divided into the first filling layer F 506 A 1  and the second filling layer F 506 A 2 . 
       FIG.  5 D  is a cross-sectional view of a display device according to another embodiment of the disclosure. Because a display device  500 D of  FIG.  5 D  is substantially the same as the display device  500 C of  FIG.  5 C , the differences between the two embodiments are mainly described below. A display device  500 D includes the red pixel unit  502 A, the green pixel unit  504 A, the blue pixel unit  506 A and the black matrix  508 C. The red pixel unit  502 A includes the light emitting element E 502 A, the color filter C 502 A and the light conversion element Q 502 A. The green pixel unit  504 A includes the light emitting element E 504 A, the color filter C 504 A and the light conversion element Q 504 A. The blue pixel unit  506 A includes the light emitting element E 506 A and the filling element F 506 A. The light emitting element E 502 A of the red pixel unit  502 A, the light emitting element E 504 A of the green pixel unit  504 A and the light emitting element E 506 A of the blue pixel unit  506 A may be disposed on a first side of the substrate  514 B. The light conversion element Q 502 A and the color filter C 502 A of the red pixel unit  502 A, the light conversion element Q 504 A and the color filter C 504 A of the green pixel unit  504 A and the light conversion element Q 506 A and the color filter C 506 A of the blue pixel unit  506 A are disposed on a second side of the substrate  514 A. The first side and the second side are opposite sides. The light emitting element E 502 A, the light emitting element E 504 A and the light emitting element E 506 A may share the electrode material layer EE, and the electrode material layer EE is provided as an outermost component of the display device  500 D without being covered with the substrate. In addition, the substrate  514 B may replace the passivation layer PV 6 A in the embodiment of  FIG.  5 A . 
       FIG.  5 E  is a cross-sectional view of a display device according to another embodiment of the disclosure. Because a display device  500 E of  FIG.  5 E  is substantially the same as the display device  500 B of  FIG.  5 B , the differences between the two embodiments are mainly described below. The display device  300 E includes a red pixel unit  502 E, a green pixel unit  504 E and the blue pixel unit  506 A. The red pixel unit  502 E includes the light emitting element E 502 A, a color filter C 502 E and the light conversion element Q 502 A. The green pixel unit  504 E includes the light emitting element E 504 A, the color filter C 504 E and the light conversion element Q 504 A. The blue pixel unit  506 A includes the light emitting element E 506 A and the filling element F 506 A. In addition, a black matrix  508 E of the display device  500 E includes a sub matrix  508 E 1  and a sub matrix  508 E 2 . The sub matrix  508 E 1  may be formed by stacking a peripheral portion PA 3  and a peripheral portion PA 4 . 
     In this embodiment, the peripheral portion PA 3  and the color filter C 504 E are the same film layer, and the peripheral portion PA 4  and the color filter C 502 E are the same film layer. For instance, the peripheral portion PA 3  may be simultaneously fabricated on the substrate  512 A when fabricating the color filter C 504 E. After the color filter C 504 E is fabricated, the color filter C 502 E and the peripheral portion PA 4  may be fabricated. Since the color filter C 504 E is manufactured earlier than the color filter C 502 E, the peripheral portion PA 4  may be stacked on the peripheral portion PA 3 . That is to say, the peripheral portion PA 3  is located between the peripheral portion PA 4  and the substrate  512 A, but not limited thereto. In addition, the sub matrix  508 E 2  is disposed on the peripheral portion PA 4 . In an embodiment, the sub matrix  508 E 2  may have a trapezoid shape wider in direction farther away from the substrate  512 A, but not limited thereto. 
       FIG.  5 F  is a cross-sectional view of a display device according to another embodiment of the disclosure. Because a display device  500 F of  FIG.  5 F  is substantially the same as the display device  500 A of  FIG.  5 A , the differences between the two embodiments are mainly described below. The display device  500 F includes a red pixel unit  502 F, a green pixel unit  504 F and a blue pixel unit  506 F. The red pixel unit  502 F, the green pixel unit  504 F and the blue pixel unit  506 F are all disposed between the substrate  512 A and the substrate  514 A. The red pixel unit  502 F includes the light emitting element E 502 A, a color filter C 502 F and a light conversion element Q 502 F. The green pixel unit  504 F includes the light emitting element E 504 A, a color filter C 504 F and a light conversion element Q 504 F. The blue pixel unit  506 F includes the light emitting element E 506 A and a filling element F 506 F. In addition, a black matrix  508 F of the display device  500 F includes a sub matrix  508 F 1 , a sub matrix  508 F 2  and a peripheral portion PA 5 . 
     Specifically, the peripheral portion PA 5  is disposed on the passivation layer PV 7 A; the sub matrix  508 F 2  is disposed on the peripheral portion PA 5 ; and the sub matrix  508 F 1  is stacked on the sub matrix  508 F 2 . The peripheral portion PA 5  and the color filter C 502 F may be the same film layer. That is to say, the peripheral portion PA 5  may be simultaneously fabricated when fabricating the color filter C 502 F in this embodiment. The peripheral portion PA 5  may be used to separate the color filter C 502 F, the color filter C 504 F and a first filling layer F 506 F 1  of the filling element F 506 F. The sub matrix  508 F 2  includes a matrix portion SM 3  and a matrix portion SM 4  sequentially stacked on the peripheral portion PA 5 . Here, the matrix portion SM 3  is filled in a gap between the color filter C 502 F, the color filter C 504 F and the first filling layer F 506 F 1 . The matrix portion SM 4  forms a structure that protrudes away from the substrate  512 A relative to the color filter C 502 F, the light color filter C 504 F and the first filling layer F 506 F 1 . The matrix portion SM 4  separates the light conversion element Q 502 F, the light conversion element Q 504 F and a second filling layer F 506 F 2  of the filling element F 506 F. 
       FIG.  5 G  is a cross-sectional view of a display device according to another embodiment of the disclosure. Because a display device  500 G of  FIG.  5 G  is substantially the same as the display device  500 A of  FIG.  5 A , the differences between the two embodiments are mainly described below. The display device  500 G includes a red pixel unit  502 G, a green pixel unit  504 G and the blue pixel unit  506 A. The red pixel unit  502 G includes the light emitting element E 502 A, a color filter C 502 G and a light conversion element Q 502 G. The green pixel unit  504 G includes the light emitting element E 504 A, a color filter C 504 G and a light conversion element Q 504 G. The blue pixel unit  506 A includes the light emitting element E 506 A and the filling element F 506 A. In addition, a black matrix  508 G of the display device  500 G includes a sub matrix  508 G 1  and a sub matrix  508 G 2 . Here, the sub matrix  508 G 1  may include a peripheral portion PA 6  and a peripheral portion PA 7 . The light emitting element E 502 A, the light emitting element E 504 A and the light emitting element E 506 A are disposed on the first side of the substrate  514 B. The light conversion element Q 502 G and the color filter C 502 G of the red pixel unit  502 G, the light conversion element Q 504 G and the color filter C 504 G of the green pixel unit  504 G and the filling element F 506 A of the blue pixel unit  506 G are disposed on the second side of the substrate  514 A. The first side and the second side are opposite sides. 
     In an embodiment, the peripheral portion PA 6  and the color filter C 502 G are the same film layer, and the peripheral portion PA 7  and the color filter C 504 G are the same film layer. For instance, the peripheral portion PA 6  may be simultaneously fabricated on the substrate  512 A when fabricating the color filter C 502 G. After the color filter C 502 G is fabricated, the color filter C 504 G and the peripheral portion PA 7  may be fabricated. Since the color filter C 502 G is manufactured earlier than the color filter C 504 G, the peripheral portion PA 7  may be partially stacked on the peripheral portion PA 6 . However, the peripheral portion PA 7  may also include a portion directly disposed on the passivation layer PV 7 A. In addition, the sub matrix  508 G 2  is disposed on the peripheral portion PA 7 . In some areas, the sub matrix  508 G 2  may partially contact the peripheral portion PA 6  and partially contact the peripheral portion PA 7 . 
     In an embodiment, the sub matrix  508 G 2  may have a trapezoid shape narrower in direction farther away from the substrate  512 A, but not limited thereto. In addition, the sub matrix  508 G 2  protrudes away from the substrate  512 A relative to the color filter C 502 G and the color filter C 504 G. In some embodiments, the light conversion element Q 502 G, the light conversion element Q 504 G and the filling element F 506 A may also be fabricated in an opening defined by the sub matrix  508 G 2  by the inkjet. A height of the sub matrix  508 G 2  helps to prevent the droplets used during the inkjet printing from spilling over and thus mixing between different materials may be prevented. 
       FIG.  5 H  is a cross-sectional view of a display device according to another embodiment of the disclosure. Because a display device  500 H of  FIG.  5 H  is substantially the same as the display device  500 A of  FIG.  5 A , the differences between the two embodiments are mainly described below. The display device  500 H includes a red pixel unit  502 H, a green pixel unit  504 H and the blue pixel unit  506 A. The red pixel unit  502 H, the green pixel unit  504 H and the blue pixel unit  506 A are all disposed between the substrate  512 A and the substrate  514 A. The red pixel unit  502 H includes the light emitting element E 502 A, a color filter C 502 H and a light conversion element Q 502 H. The green pixel unit  504 H includes the light emitting element E 504 A, a color filter C 504 H and a light conversion element Q 504 H. The blue pixel unit  506 A includes the light emitting element E 506 A and the filling element F 506 A. In addition, a black matrix  508 H of the display device  500 H includes a sub matrix  508 H 1  and a sub matrix  508 H 2 . Here, the sub matrix  508 H 1  may include a peripheral portion PA 8  and a peripheral portion PA 9 . 
     The peripheral portion PA 8  and the color filter C 504 H are the same film layer, and the peripheral portion PA 9  and the color filter C 502 H are the same film layer. For instance, the peripheral portion PA 8  may be simultaneously fabricated on the substrate  512 A when fabricating the color filter C 504 H. After the color filter C 504 H is fabricated, the color filter C 502 H and the peripheral portion PA 9  may be fabricated. Since the color filter C 504 H is manufactured earlier than the color filter C 502 H, the peripheral portion PA 9  may be partially stacked on the peripheral portion PA 8 . However, the peripheral portion PA 9  may also include a portion directly disposed on the passivation layer PV 7 A. In addition, the sub matrix  508 H 2  is disposed on the peripheral portion PA 9 . In some areas, the sub matrix  508 H 2  may partially contact the peripheral portion PA 8  and partially contact the peripheral portion PA 9 . In addition, the sub matrix  508 H 2  may have a trapezoid shape narrower in direction farther away from the substrate  512 A, but not limited thereto. In addition, the sub matrix  508 H 2  protrudes away from the substrate  512 A relative to the color filter C 502 H and the color filter C 504 H. In some embodiments, the light conversion element Q 502 H, the light conversion element Q 504 H and the filling element F 506 A may also be fabricated in an opening defined by the sub matrix  508 H 2  by the inkjet printing. A height of the sub matrix  508 H 2  helps to prevent the droplets used during the inkjet printing from spilling over and thus mixing between different materials may be prevented. Here, the passivation layer PV 6 A may be disposed on a top surface of the sub matrix  508 H 2  and may contact top surfaces of the light conversion element Q 502 H, the light conversion element Q 504 H and the filling element F 506 A, but not limited thereto. 
       FIG.  5 I  is a cross-sectional view of a display device according to another embodiment of the disclosure. Because a display device  500 I of  FIG.  5 I  is substantially the same as the display device  500 A of  FIG.  5 A , the differences between the two embodiments are mainly described below. The display device  500 I of  FIG.  5 I  includes a red pixel unit  502 I, a green pixel unit  504 I and a blue pixel unit  506 I. The red pixel unit  502 I, the green pixel unit  504 I and the blue pixel unit  506 I are all disposed between the substrate  512 A and the substrate  514 A. The red pixel unit  502 I includes the light emitting element E 502 A, a light conversion element Q 502 I and a color filter C 502 I. The green pixel unit  504 I includes the light emitting element E 504 A, a light conversion element Q 504 I and a color filter C 504 I. The blue pixel unit  506 I includes the light emitting element E 506 A and a filling element F 506 I. The specific structures and designs of the light emitting element E 502 A, the light emitting element E 504 A and the light emitting element E 506 A are substantially the same as those in the embodiment of  FIG.  5 A , which will not be repeated hereinafter. 
     In this embodiment, because the display device  500 I does not include the black matrix, the light conversion element Q 502 I, the light conversion element Q 504 I and a first filling layer F 506 I 1  of the filling element F 506 I are disposed adjacent to each other. The light conversion element Q 502 I is stacked on the color filter C 502 I. The light conversion element Q 504 I is stacked on the color filter C 504 I. A second filling layer F 506 I 2  of the filling element F 506 E is stacked on the first filling layer F 506 I 1 . The color filter C 502 I, the light conversion element Q 502 I, the color filter C 504 I, the light conversion element Q 504 I and the filling element F 506 I may be fabricated by, for example, the photo lithography. Therefore, even though the display device  500 I does not include the black matrix, the materials of the light conversion element Q 502 I and the light conversion element Q 504 I will not mix with each other, and the materials of the color filter C 502 I and the color filter C 504 I will not mix with each other. In addition, the materials of the color filter C 502 I, the light conversion element Q 502 I, the color filter C 504 I and the light conversion element Q 504 I will not contaminate with the material of the filling element F 506 E either. 
       FIG.  5 J  is a partial cross-sectional view of a display device according to another embodiment of the disclosure. Because a display device  500 J of  FIG.  5 J  is substantially the same as the display device  500 I of  FIG.  5 I , the difference between the two embodiments is mainly an arrangement position of the substrate  514 B. The display device  500 J includes the red pixel unit  502 I, the green pixel unit  504 I and the blue pixel unit  506 I. The red pixel unit  502 I includes the light emitting element E 502 A, the color filter C 502 I and the light conversion element Q 502 I. The green pixel unit  504 I includes the light emitting element E 504 A, the color filter C 504 I and the light conversion element Q 504 I. The blue pixel unit  506 I includes the light emitting element E 506 A and the filling element F 506 I. In the display device  500 I, the light emitting element E 502 A of the red pixel unit  502 I, the light emitting element E 504 A of the green pixel unit  504 I and the light emitting element E 506 A of the blue pixel unit  506 I may be disposed on the first side of the substrate  514 B. The light conversion element Q 502 I and the color filter C 502 I of the red pixel unit  502 I, the light conversion element Q 504 I and the color filter C 504 I of the green pixel unit  504 I and the filling element F 506 I of the blue pixel unit  506 I are disposed on the second side of the substrate  514 B. The first side and the second side are opposite sides. In addition, the light emitting element E 502 I, the light emitting element E 504 I and the light emitting element E 506 I may share the electrode material layer EE, and the electrode material layer EE is provided as an outermost component of the display device  500 I without being covered with the substrate. The foregoing embodiments of  FIG.  5 A  to  FIG.  5 J  include two substrates, but the disclosure is not limited thereto. For instance, the substrate  514 A in  FIG.  5 A ,  FIG.  5 C ,  FIG.  5 F ,  FIG.  5 H  and  FIG.  5 I  may be omitted so that a single substrate structure is provided. 
       FIG.  6 A  is a partial cross-sectional view of a display device according to an embodiment of the disclosure. In  FIG.  6 A , a display device  600 A includes a red pixel unit  602 A, a green pixel unit  604 A, a blue pixel unit  606 A, a black matrix  608 A and a substrate  612 A. The red pixel unit  602 A, the green pixel unit  604 A, the blue pixel unit  606 A and the black matrix  608 A are all disposed on the substrate  612 A. The red pixel unit  602 A includes a light emitting element E 602 A, a light conversion element Q 602 A and a color filter C 602 A. The green pixel unit  604 A includes a light emitting element E 604 A, a light conversion element Q 604 A and a color filter C 604 A. The blue pixel unit  606 A includes a light emitting element E 606 A and a filling element F 606 A. In this embodiment, the light emitting element E 602 A, the light emitting element E 604 A and the light emitting element E 606 A are all disposed on the substrate  612 A, and a passivation layer PV 8 A is disposed on the substrate  612 A. The black matrix  608 A, the light conversion element Q 602 A, the color filter C 602 A, the light conversion element Q 604 A, the color filter C 604 A and the filling element F 606 A are all disposed on the passivation layer PV 8 A. In addition, a passivation layer PV 9 A is further provided on the substrate  612 A to cover the color filter C 602 A, the color filter C 604 A, the filling element F 606 A and the black matrix  608 A. 
     The light emitting element E 602 A includes the active element TA and a light emitting unit EL 6 A. The light emitting element E 604 A includes the active element TB and a light emitting unit EL 6 B. The light emitting element E 606 A includes the active element TC and a light emitting unit EL 6 C. In this embodiment, the light emitting unit EL 6 A, the light emitting unit EL 6 B and the light emitting unit EL 6 C are respectively connected to the active element TA, the active element TB and the active element TC, and are not connected to each other. Each of the light emitting unit EL 6 A, the light emitting unit EL 6 B, and the light emitting unit EL 6 C is, for example, a light emitting diode die or a packaged light emitting diode package. Lights emitted by the light emitting element E 602 A, the light emitting element E 604 A and the light emitting element E 606 A are emitted away from the active element TA, the active element TB and the active element TC. A pixel definition layer PDL 7  is provided on the substrate  612 A, which surrounds peripheries of the light emitting unit EL 6 A, the light emitting unit EL 6 B and the light emitting unit EL 6 C to separate the light emitting unit EL 6 A, the light emitting unit EL 6 B and the light emitting unit EL 6 C from each other and ensure that each of the light emitting element E 602 A, the light emitting element E 602 B and the light emitting element E 602 C may emit light independently. In addition, the pixel definition layer PDL 7  may be a white insulation layer or a black insulation layer. In some embodiments, the pixel definition layer PDL 7  may be used to block lights emitted from the light emitting unit EL 6 A, the light emitting unit EL 6 B and the light emitting unit EL 6 C from a lateral side, and prevent the lights from the light emitting unit EL 6 A, the light emitting unit EL 6 B and the light emitting unit EL 6 C from mixing with each other. 
     The passivation layer PV 8 A may be, for example, filled in an uneven structure formed by the pixel definition layer PDL 7 . The passivation layer PV 8 A may be formed by stacking a plurality of layers together, but not limited thereto. On the passivation layer PV 8 A, the light conversion element Q 602 A is disposed between the passivation layer PV 8 A and the color filter C 602 A, and the light conversion element Q 604 A is disposed between the passivation layer PV 8 A and the color filter C 604 A. In this way, the light emitted by the light emitting element E 602 A will pass through the light conversion element Q 602 A before entering the color filter C 602 A. Similarly, the light emitted by the light emitting element E 604 A will pass through the light conversion element Q 604 A before entering the color filter C 604 A. A filtering wavelength of the color filter C 602 A may correspond to a conversion wavelength of the light conversion element Q 602 A, and a filter wavelength of the color filter C 604 A may correspond to a conversion wavelength of the light conversion element Q 604 A. For example, if the light conversion element Q 602 A is adapted to convert the blue light or the ultraviolet light into the red light, the color filter C 602 A is a red filter layer. If the light conversion element Q 604 A is adapted to convert the blue light or the ultraviolet light into the green light, the color filter C 604 A is a green filter layer. In this way, the lights emitted by the light emitting unit EL 6 A and the light emitting unit EL 6 B may be the blue light or the ultraviolet light. The filling element F 606 A may not provide a color filtering function or a wavelength conversion function, but allows the light emitted by the light emitting element E 606 A to pass directly. Therefore, the light emitted by the light emitting unit EL 6 C of the blue pixel unit  606 A is, for example, the blue light. However, in other embodiments, the filling element F 606 A may be a blue filter layer. In some embodiments, scattering particles may be distributed in the light conversion element Q 602 A, the light conversion element Q 604 A and the filling element F 606 A to provide the function of scattering light. However, the disclosure is not limited in this regard. 
     In this embodiment, the filling element F 606 A may include a first filling layer F 606 A 1  and a second filling layer F 606 A 2 , and the second filling layer F 606 A 2  is located between the first filling layer F 606 A 1  and the passivation layer PV 8 A. The black matrix  608 A includes a sub matrix  608 A 1  and a sub matrix  608 A 2  disposed on the substrate  612 A. Here, the sub matrix  608 A 1  and the sub matrix  608 A 2  are stacked together and the sub matrix  608 A 1  is located between the passivation layer PV 8 A and the sub matrix  608 A 2 . The sub matrix  608 A 1  is configured to separate the light conversion element Q 602 A, the light conversion element Q 604 A and the first filling layer F 606 A 1 . The sub matrix  608 A 2  is configured to separate the color filter C 602 A, the color filter C 604 A and the second filling layer F 606 A 2 . In this embodiment, the sub matrix  608 A 1  is disposed between the sub matrix  608 A 2  and the passivation layer PV 8 A. In some embodiments, the sub matrix  608 A 1  may be fabricated on the passivation layer PV 8 A first, and then the sub matrix  608 A 2  may be fabricated on the sub matrix  608 A 1 . A width of the sub matrix  608 A 1  may be greater than a width of the sub matrix  608 A 2 . The sub matrix  608 A 1  and the sub matrix  608 A 2  may have a trapezoid shape which is gradually reduced away from the substrate  612 A, but not limited thereto. 
     The light conversion element Q 602 A and the light conversion element Q 604 A may be fabricated by the inkjet printing. In some embodiments, after the sub matrix  608 A 1  is fabricated on the substrate  612 A, a inkjet device may be used to drop a light conversion material into a groove defined by the sub matrix  608 A 1  on the substrate  612 A, and then the light conversion material is cured to form the light conversion element Q 602 A and the light conversion element Q 604 A. A height of the sub matrix  608 A 1  protruding away from the substrate  612 A by a surface of the passivation layer PV 8 A helps to ensure that the droplets of the light conversion material will not overflow and thus contamination between different light conversion materials may be reduced. After the light conversion material is cured to form the light conversion element Q 602 A and the light conversion element Q 604 A, the sub matrix  608 A 2  may be fabricated on the sub matrix  608 A 1 . Then, the inkjet device may be used to drop a color filter material into a groove defined by the sub matrix  608 A 2  on the substrate  612 A. In addition, a filling material may also be filled into a groove defined by the sub matrix  608 A 2  and the sub matrix  608 A 2  on the substrate  612 A. Then, after the color liter material and the filling material are cured, the color filter C 602 A, the color filter C 604 A and the filter element F 606 A may be formed. In some embodiments, the first filling layer F 606 A 1  of the filling element F 606 A may be fabricated before the sub matrix  608 A 2  is fabricated, and the second filling layer F 606 A 2  of the filling element F 606 A may be fabricated after the sub matrix  608 A 2  is fabricated. In some other embodiments, the filling element F 606 A may be fabricated by using one single inkjet process without having it done layer by layer. In other words, the filling element F 606 A may be a single film layer. 
     A layout of the red pixel unit  602 A, the green pixel unit  604 A and the blue pixel unit  606 A may be similar to the description of the foregoing embodiment. In other words, when the display device  600 A is lit, it may be may be observed under the optical microscope that, a lighting area of the red pixel unit  602 A is smaller than a lighting area of the green pixel unit  604 A and greater than a lighting area of the blue pixel unit  606 A. A ratio of the lighting area of the green pixel unit  604 A to the lighting area of the red pixel unit  602 A is, for example, ranged from 1.02 to 2.90 or ranged from 1.37 to 2.07. In some embodiments, a ratio of the lighting area of the green pixel unit  604 A to the lighting area of the blue pixel unit  606 A is, for example, ranged from 1.68 to 3.29 or ranged from 1.71 to 2.35. In some embodiments, a ratio of the lighting area of the red pixel unit  602 A to the lighting area of the blue pixel unit  606 A is, for example, ranged from 1.02 to 1.84 or ranged from 1.03 to 1.37. 
       FIG.  6 B  is a cross-sectional view of a display device according to another embodiment of the disclosure. Because a display device  600 B of  FIG.  6 B  is substantially the same as the display device  600 A of  FIG.  6 A , the differences between the two embodiments are mainly described below. In  FIG.  6 B , a display device  600 B includes the substrate  612 A and a substrate  614 B, and the red pixel unit  602 A, the green pixel unit  604 A and the blue pixel unit  606 A are disposed between the substrate  612 A and the substrate  614 B. Because the substrate  614 B may be used to replace the passivation layer PV 9 A in  FIG.  6 A , the display device  600 B does not have the passivation layer PV 9 A. The red pixel unit  602 A includes the light emitting element E 602 A, the light conversion element Q 602 A and the color filter C 602 A. The green pixel unit  604 A includes the light emitting element E 604 A, the light conversion element Q 604 A and the color filter C 604 A. The blue pixel unit  606 A includes the light emitting element E 606 A and the filling element F 606 A. In addition, a black matrix  608 B of the display device  600 B includes a sub matrix  608 B 1  and a sub matrix  608 B 2  sequentially stacked on the substrate  612 A. Here, the sub matrix  608 B 1  is configured to separate the light conversion element Q 602 , the light conversion element Q 604 A and the filling element F 606 A. The sub matrix  608 B 2  is configured to separate the color filter C 602 A, the color filter C 604 A and the filling element F 606 A. 
     In this embodiment, both the sub matrix  608 B 1  and the sub matrix  608 B 2  have a trapezoidal shape. In some embodiments, the sub matrix  608 B 1  may be fabricated on the substrate  614 B first, and then the light conversion element Q 602 A, the light conversion element Q 604 A and the first filling layer F 606 A 1  of the filling element F 606 A may be formed on the substrate  612 B. The sub matrix  608 B 2  may be fabricated on the substrate  614 B first, and then the color filter C 602 A, the color filter C 604 A and the second filling layer F 606 A 2  of the filling element F 606 A may be fabricated on the substrate  614 B and located in a groove defined by the sub matrix  608 B 2 . Then, the substrate  612 A and the substrate  614 B are attached together so the sub matrix  608 B 1  and the sub matrix  608 B 2  are stacked together to form the black matrix  608 B. In some embodiments, a material of the sub matrix  608 B 2  may comprise a black photoresist. Also, the sub matrix  608 B 1  and the sub matrix  608 B 2  may be fabricated by the same material, but not limited thereto. In an alternative embodiment, the material of one or both of the sub matrix  608 B 1  and the sub matrix  608 B 2  may comprise a color photoresist material, such as a red photoresist material, a green photoresist material, etc. 
       FIG.  6 C  is a cross-sectional view of a display device according to another embodiment of the disclosure. Because a display device  600 C of  FIG.  6 C  is substantially the same as the display device  600 A of  FIG.  6 A , the differences between the two embodiments are mainly described below. The display device  600 C of  FIG.  6 C  includes a red pixel unit  602 C, a green pixel unit  604 C and the blue pixel unit  606 A. The red pixel unit  602 C includes the light emitting element E 602 A, the light conversion element Q 602 A and a color filter C 602 C. The green pixel unit  604 C includes the light emitting element E 604 A, the light conversion element Q 604 A and a color filter C 604 C. The blue pixel unit  606 A includes the light emitting element E 606 A and the filling element F 606 A. The specific structures and designs of the light conversion element Q 602 A, the light conversion element Q 604 A, the light emitting element E 602 A, the light emitting element E 604 A, the light emitting element E 606 A and the filling element F 606 A are substantially the same as those in the embodiment of  FIG.  6 A , which will not be repeated hereinafter. In addition, the display device  600 C further includes a black matrix  608 C, and the structural design of the black matrix  608 C is substantially the same as the sub matrix  608 A 1  of  FIG.  6 A . 
     In this embodiment, the light conversion element Q 602 A, the light conversion element Q 604 A and the filling element F 606 A may be spaced apart by the black matrix  608 C, and the color filter C 602 C, and the color filter C 604 C and the filling element F 606 A may be disposed adjacent to each other. That is to say, the color filter C 602 C, the color filter C 604 C and the filling element F 606 A are in contact with each other on the sidewalls. In addition, boundaries between the color filter C 602 C, the color filter C 604 C and the filling element F 606 A are located on the black matrix  608 C, for example. In some embodiments, the boundaries between the color filter C 602 C, the color filter C 604 C and the filling element F 606 A are oblique boundaries, which are inclined relative to a normal direction of the substrate  612 A. In some embodiments, a boundary B 1  between the color filter C 602 C and the color filter C 604 C inclined closer to a center of the color filter C 604 C in direction farther away from the substrate  612 A, and a boundary B 2  between the color filter C 604 C and the filling element F 606 A inclined closer to a center of the color filter C 604 C in direction farther away from the substrate  612 A. Accordingly, the green pixel unit  604 C and the color filter C 604 C have a trapezoid shape narrower in direction farther away from the substrate  612 A. The color filter C 602  of the red pixel unit  602 C and the filling element F 606 A of the blue pixel unit  606 A have a trapezoid shape wider in direction farther away from the substrate  612 A, but not limited thereto. 
     In summary, according to the display devices of the embodiments of the disclosure, the sizes of the lighting areas of the pixel units of different colors may be adjusted so that the display light of each color has a required ratio of light radiation. Therefore, the display devices in the embodiments of the disclosure may meet the needs of application products, for example, may display a required display effect. For instance, the red pixel unit may have the lighting area greater than the lighting area of the blue pixel unit and less than the lighting area of the green pixel unit to achieve the required ratio of light radiation. In this way, the white point presented when the display devices are lit may achieve the set goal. 
     Finally, it should be noted that the foregoing embodiments are merely used for describing the technical solutions of the disclosure, but are not intended to limit the disclosure. Although the disclosure is described in detail with reference to the foregoing embodiments, a person of ordinary skill in the art should understand that, modifications may still be made to the technical solutions in the foregoing embodiments, or equivalent replacements may be made to part or all of the technical features; and these modifications or replacements will not cause the essence of corresponding technical solutions to depart from the scope of the technical solutions in the embodiments of the disclosure.