Patent Publication Number: US-2023145241-A1

Title: Electronic device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of application Ser. No. 17/752,945, filed May 25, 2022, which is a Continuation of application Ser. No. 17/130,172, filed Dec. 22, 2020 (now U.S. Pat. No. 11,366,545, issued in Jun. 21, 2022), which is a Continuation of application Ser. No. 16/554,685, filed Aug. 29, 2019, which is a Continuation of Application No. 15/670,120, filed Aug. 7, 2017, which claims the benefit of provisional Application No. 62/500,539, filed May 3, 2017, the entirety of which is incorporated by reference herein. 
    
    
     BACKGROUND 
     Technical Field 
     The disclosure relates to display devices, and in particular to display devices including light-emitting diodes. 
     Description of the Related Art 
     As digital technology develops, display devices are becoming more widely used in our society. For example, display devices have been applied in modern information and communication devices such as televisions, notebook computers, desktop computers, mobile phones (e.g., smartphones). In addition, each generation of display devices has been developed to be thinner, lighter, smaller, and more fashionable. 
     Among the various types of display devices, light-emitting diode (LED) display devices are becoming popular due to the advantages of LEDs which include high efficiency and long lifespans. 
     However, existing LED display devices have not been satisfactory in every respect. For example, the conductive line or conductive electrode may be easily cracked during the formation of a curved display device). 
     BRIEF SUMMARY 
     Some embodiments of the disclosure provide a display device. The display device includes a substrate having a first edge and a second edge opposite to the first edge, wherein there is a first distance between the first edge and the second edge; a plurality of light-emitting units disposed on the substrate; and a conductive line disposed on the substrate and electrically connected to at least one of the plurality of light-emitting units, wherein the conductive line includes an undulating edge, wherein the conductive line has an extending length, and wherein the extending length is greater than or equal to half of the first distance and is less than or equal to the first distance. 
     Some embodiments of the disclosure provide a display device. The display device includes a substrate; a plurality of light-emitting units disposed on the substrate; and a conductive line disposed on the substrate and electrically connected to at least one of the plurality of light-emitting units, wherein the conductive line includes a plurality of openings. 
     A detailed description is given in the following embodiments with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure can be more fully understood from the following detailed description when read with the accompanying figures. It is worth noting that in accordance with standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. 
         FIG.  1 A  is a schematic side view of the curved display device  10  according to some embodiments of the present disclosure. 
         FIG.  1 B  is a schematic side view of the curved display device  10 ′ according to some embodiments of the present disclosure. 
         FIG.  2 A  is a schematic top view of the display device  20  according to First Embodiment of the present disclosure. 
         FIG.  2 B  is a schematic top view of a portion of the display region  202  of the display device  20  according to some embodiments of the present disclosure. 
         FIG.  2 C  is a schematic top view of a portion of the display region  202  of the display device  20  according to some embodiments of the present disclosure. 
         FIG.  2 D  is a schematic top view of a portion of the display region  202  of the display device  20  according to some embodiments of the present disclosure. 
         FIG.  2 E  is a schematic top view of a portion of the display region  202  of the display device  20  according to some embodiments of the present disclosure. 
         FIG.  2 F  is a schematic top view of a portion of the conductive line  208  according to some embodiments of the present disclosure. 
         FIG.  2 G  is a schematic top view of a portion of the conductive line  208  according to some embodiments of the present disclosure. 
         FIG.  2 H  is a schematic top view of the display device  20  according to some embodiments of the present disclosure. 
         FIG.  2 I  is a schematic top view of the display device  20  according to some embodiments of the present disclosure. 
         FIG.  2 J  is a schematic top view of the display device  20  according to some embodiments of the present disclosure. 
         FIG.  3 A  is a schematic top view of a portion of the display region  202  of the display device  30  according to Second Embodiment of the present disclosure. 
         FIG.  3 B  is a schematic top view of a portion of the display region  202  of the display device  30  according to some embodiments of the present disclosure. 
         FIG.  3 C  is a schematic top view of a portion of the display region  202  of the display device  30  according to some embodiments of the present disclosure. 
         FIG.  3 D  is a schematic top view of a portion of the conductive electrode  210  according to some embodiments of the present disclosure. 
         FIG.  3 E  is a schematic top view of a portion of the conductive electrode  210  according to some embodiments of the present disclosure. 
         FIG.  4 A  is a schematic cross-sectional view of the display device  40  according to some embodiments of the present disclosure. 
         FIG.  4 B  is a schematic cross-sectional view of the display device  40  according to some embodiments of the present disclosure. 
         FIG.  4 C  is a schematic cross-sectional view of the display device  40  according to some embodiments of the present disclosure. 
         FIG.  5    is a schematic cross-sectional view of the display device  50  according to Third Embodiment of the present disclosure. 
         FIG.  6 A  is a schematic side view of the display device  60  according to Fourth Embodiment of the present disclosure. 
         FIG.  6 B  is a schematic side view of the display device  70  according to an embodiment of the present disclosure. 
         FIG.  7 A  is a schematic top view of the display device  80  according to Fifth Embodiment of the present disclosure. 
         FIG.  7 B  is a schematic top view of the display device  80  according to some embodiments of the present disclosure. 
         FIG.  7 C  is a schematic top view of the display device  80  according to some embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The following disclosure provides many different embodiments, or examples, for implementing different features of the subject matter provided. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various embodiments. This repetition is for simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. 
     Some embodiments are described below. Throughout the various views and illustrative embodiments, like reference numbers are used to designate like features. It should be understood that additional operations can be provided before, during, and after the method, and some of the operations described can be replaced or eliminated for other embodiments of the method. 
       FIG.  1 A  is a schematic side view of the curved display device  10  according to some embodiments of the present disclosure. As shown in  FIG.  1 A , the curved display device  10  includes one or more curved portions  100 . For example, the curved portions  100  can include the end portions of the display device  10 . In some embodiments, the curved portions  100  (e.g., two curved portions  100 ) are symmetrical with respect to the center line C of the curved display device  10  as shown in  FIG.  1 A . 
       FIG.  1 B  is a schematic side view of another curved display device  10 ′ according to embodiments of the present disclosure. As shown in  FIG.  1 B , the curved display device  10 ′ can have curved portion  100 ′ including the center portion of the display device  10 ′. 
     It should be noted that the curved display devices (e.g., curved display device  10  or curved display device  10 ′) of some embodiments of the present disclosure can be foldable display devices. However, in other embodiments, the shape of the curved display device is substantially fixed. 
     First Embodiment 
     First Embodiment of the present disclosure provides some display devices which can be used to form curved display devices. The conductive lines of the display devices of First Embodiment may have a wavy shape and/or include one or more openings, which may avoid or reduce the formation of cracks in the step of using these display devices to form curved display devices. 
       FIG.  2 A  is a schematic top view of the display device  20  according to First Embodiment of the present disclosure. The display device  20  can be used to form a curved display device (e.g., a curved display device with a side view the same as, or similar to the curved display devices  10  or  10 ′ discussed above). For example, the display device  20  can be bent to form a curved display device. 
     As shown in  FIG.  2 A , the display device  20  can include a display region  202  and a non-display region  204  adjacent to the display region  202 . For example, the non-display region  204  can surround or enclose the display region  202 , as shown in  FIG.  2 A . The display region  202  can refer to the display region in the display device  20  in which the light-emitting units (e.g., light-emitting diodes) are disposed. On the other hand, the non-display region  204  refers to a region other than the display region  202  in the display device  20 . For example, an integrated circuit (IC), a demultiplexer (DEMUX), a gate driver on panel (GOP), other applicable devices or components, or a combination thereof may be disposed in the non-display region  204 . For example, the devices or components disposed in the non-display region  204  may be electrically connected to the light-emitting units (e.g., light-emitting diodes) disposed in the display region  202  to provide some desired functions (e.g., providing driving signal to the light-emitting units disposed in the display region  202 ). 
     As shown in  FIG.  2 A , the display device  20  includes a substrate  200  having a first edge  200   a  and a second edge  200   b  opposite to the first edge  200   a.  In some embodiments, the first edge  200   a  and the second edge  200   b  are substantially parallel to each other and are spaced apart by a first distance Di (e.g., 5 cm to 10 cm). For example, the substrate  200  of the display device  20  may include polyimide, glass, other applicable materials, or a combination thereof. It should be noted that the elements of the display device  20  formed on the substrate  200  are not shown in  FIG.  2 A , and will be discussed in the following paragraph. 
     Then, referring to  FIG.  2 B , a schematic top view of a portion of the display region  202  of the display device  20  is illustrated. As shown in  FIG.  2 B , the display region  202  can include a plurality of light-emitting units  206  (e.g., light-emitting diodes), one or more conductive lines  208 , and one or more conductive electrodes  210 . 
     In this embodiment, a sub-pixel  212  has two light-emitting units  206  (e.g., light-emitting diodes). However, the sub-pixel  212  may have less or more than two light-emitting units  206  with the same color in other embodiments. In some embodiments, adjacent sub-pixels  212  (e.g., three sub-pixels  212 ) can form a pixel. For example, the pixel can include sub-pixels  212  containing light-emitting units  206  of different colors (e.g., red, green, blue, or a combination thereof). 
     For example, the material of the conductive electrodes  210  can include, but is not limited to, indium tin oxide (ITO), tin oxide (SnO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), indium tin zinc oxide (ITZO), antimony tin oxide (ATO), antimony zinc oxide (AZO), metal, or a combination thereof. For example, the material of the conductive lines  208  can include, but is not limited to, indium tin oxide (ITO), tin oxide (SnO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), indium tin zinc oxide (ITZO), antimony tin oxide (ATO), antimony zinc oxide (AZO), metal, or a combination thereof. For example, the conductive electrodes  210  and the conductive lines  208  may be respectively formed by a deposition process followed by a lithography process and an etching process. 
     In some embodiments, the conductive line  208  can be a common line, the conductive electrode  210  can be a common electrode, and the conductive line  208  can be electrically connected to at least one of the light-emitting units  206  through the conductive electrode  210 . 
     In some embodiments, the one or more conductive electrodes  210  can be disposed on the one or more conductive lines  208  and the plurality of light-emitting units  206 . In other words, the one or more conductive lines  208  and the plurality of light-emitting units  206  can be disposed between the substrate  200  and the one or more conductive electrodes  210 . 
     In some embodiments, the conductive line  208  may have a wavy shape. For example, as shown in  FIG.  2 B , the conductive line  208  may include an undulating edge  208   a  (e.g., an undulating edge extending along a direction substantially perpendicular to the first edge  200   a  and/or the second edge  200   b  of the substrate  200 ), and thus the formation of cracks in the conductive line  208  during the step of forming a curved display device (e.g., bending the display device  20  to form a curved display device) may be avoided or reduced. 
     In some embodiments, as shown in  FIG.  2 B , the conductive line  208  can extend along a direction substantially perpendicular to the first edge  200   a  and/or the second edge  200   b  of the substrate  200  (referring to  FIG.  2 A ), and an extending length Li (e.g., a distance measured in a direction perpendicular to the first edge  200   a  and/or the second edge  200   b  of the substrate  200 ) of the conductive line  208  can be greater than or equal to half of the first distance D 1  and be less than or equal to the first distance Di (i.e., 0.5 D 1 ≤L 1 ≤D 1 ). In some embodiments, since the extending length L 1  is greater than or equal to half of the first distance D 1  and less than or equal to the first distance D 1 , a better device performance can be obtained. 
       FIGS.  2 C,  2 D,  2 E,  2 F, and  2 G  illustrate some conductive lines  208  of some embodiments of the present disclosure which also may avoid or reduce the formation of cracks during the step of forming a curved display device. 
     Referring to  FIG.  2 C , one difference between the embodiments illustrated in  FIG.  2 C  and  FIG.  2 B  is that the conductive line  208  of the embodiments illustrated in  FIG.  2 C  further includes one or more openings  214 . For example, a pattering process including a lithography process followed by an etching process may be used to form the one or more openings  214  in the conductive line  208 . In some embodiments, the opening  214  may have a shape including a first curved portion  214   a  (e.g., the round corners of the rectangular opening  214 ), and thus the mechanical property of the conductive line  208  may be further improved. In other embodiments, the opening  214  may also be substantially oval-shaped (e.g., as shown in  FIG.  2 D ), substantially square, substantially rectangular, substantially round, substantially oblong, substantially triangular, polygon, irregularly-shaped, other applicable shapes, or a combination thereof. 
     Referring to  FIG.  2 E , one difference between the embodiments illustrated in  FIG.  2 C  and  FIG.  2 E  is that the conductive line  208  of the embodiments illustrated in  FIG.  2 E  includes a substantially straight edge  208   a  (e.g., a straight edge extending along a direction substantially perpendicular to the first edge  200   a  and/or the second edge  200   b  of the substrate  200 ). Notably, the opening  214  of the embodiments illustrated in  FIG.  2 E  may also be substantially oval-shaped, substantially square, substantially rectangular, substantially round, substantially oblong, substantially triangular, polygon, irregularly-shaped, other applicable shapes, or a combination thereof. 
     In some embodiments, as shown in  FIGS.  2 C,  2 D, and  2 E , the one or more openings  214  may be located between adjacent conductive electrodes  210 . 
     In some embodiments, as shown in  FIG.  2 F , a single conductive line  208  may include a plurality of openings  214  having different shapes or sizes to increase design flexibility. 
     In some embodiments, as shown in  FIG.  2 G , the conductive line  208  may have a partially undulating edge  208   a.  For example, the edge  208   a  of the conductive line  208  may include a substantially straight portion  208   a ′ and a wavy portion  208   a ″, where the wavy portion is provided at weak points that are prone to cracking. 
     In some embodiments, the conductive lines  208  are common lines that can be used to transmit common signals from an IC disposed in the non-display region  204  of the display device  20  to the light-emitting units  206  disposed in the display region  202  of the display device  20 . For example, as shown in  FIG.  2 H , the common signals can be transmitted from an IC  216  into the display region  202  of the display device  20  through the common lines  208  in a direction substantially perpendicular to the first edge  200   a  and/or the second edge  200   b  of the substrate  200 . As shown in  FIG.  2 H , the common lines  208  may be electrically connected to the IC  216  through another common line  218  disposed in the non-display region  204  of the substrate  200 . In some embodiments, the common line  218  may also have a wavy shape, and/or include a plurality of openings as do the common lines  208  discussed above. In some embodiments, the common line  218  and the common lines  208  may be disposed in different layers, and in such cases one or more vias may be used to electrically connect the common line  218  to the common lines  208 . In some embodiments, the common line  218  and the common lines  208  may be disposed in the same layer, and the common line  218  and the common lines  208  may be formed by a same process (e.g., deposition, lithography, etching, other applicable processes, or a combination thereof). As shown in  FIG.  2 H , a demultiplexer (DEMUX)  222 ′ electrically connected to the IC  216 , and a gate driver on panel  222  electrically connected to the IC  216  may also be disposed in the non-display region  204  of the display device  20 . In addition, as shown in  FIG.  2 H , the IC  216  may be electrically connected to a printed circuit board  220 . 
     In some embodiments, as shown in  FIG.  2 I , the common signals can be transmitted from the IC  216  into the display region  202  of the display device  20  through common lines  224  extending along a direction substantially parallel to the first edge  200   a  and/or the second edge  200   b  of the substrate  200 , and thus the common signals are transmitted into the display region  202  of the display device  20  in the direction substantially parallel to the first edge  200   a  and/or the second edge  200   b.  In some embodiments, the common lines  224  may also have a wavy shape, and/or include a plurality of openings as do the common lines  208  discussed above. 
     In some embodiments, as shown in  FIG.  2 J , the common signals can be transmitted into the display region  202  of the display device  20  through both the common lines  208  extending along a direction that is substantially perpendicular to the first edge  200   a  and/or the second edge  200   b  of the substrate  200 , and the common lines  224  extending along a direction that is substantially parallel to the first edge  200   a  and/or the second edge  200   b  of the substrate  200 . In other words, the common signals can be transmitted into the display region  202  of the display device  20  in two directions substantially perpendicular to each other. 
     Understandably,  FIGS.  2 H,  2 I, and  2 J  are schematic top views of some display devices according to some embodiments of the present disclosure, and the elements illustrated in these FIGS. may be disposed in the same layer or in different layers. 
     It should be noted that the curved display devices formed of the display devices of the above embodiments may include technical features which are the same as or similar to the technical features of the display devices of the above embodiments. For example, the conductive lines may still have a wavy shape and/or include one or more openings in the curved display devices formed of the display devices of the above embodiments. These curved display devices are intended to be included within the scope of the present disclosure. 
     Second Embodiment 
       FIG.  3 A  is a schematic top view of a portion of the display region  202  of the display device  30  according to Second Embodiment of the present disclosure. One difference between Second Embodiment and the above embodiments is that the one or more conductive electrodes  210  (e.g., a common electrode) may have a wavy shape and/or include one or more openings, which may avoid or reduce the formation of cracks in the one or more conductive electrodes during the step of forming a curved display device (e.g., bending the display device  30  to form a curved display device). 
     As shown in  FIG.  3 A , the conductive electrode  210  may have a wavy shape. For example, as shown in  FIG.  3 A , the conductive electrode  210  may include an undulating edge  210   a  (e.g., an undulating edge extending along a direction substantially parallel to the first edge  200   a  and/or the second edge  200   b  of the substrate  200 ). 
     In some embodiments, as shown in  FIG.  3 B , the conductive electrode  210  may have one or more openings  302 . For example, a pattering process including a lithography process followed by an etching process may be used to form the one or more openings  302  in the conductive electrode  210 . In some embodiments, the opening  302  may have a shape including a first curved portion  302   a  (e.g., the round corners of the rectangular opening  302 ), and thus the mechanical property of the conductive electrode  210  may be further improved. In other embodiments, the opening  302  may also be substantially oval-shaped, substantially square, substantially rectangular, substantially round, substantially oblong, substantially triangular, polygon, irregularly-shaped, other applicable shape, or a combination thereof. 
     In some embodiments, as shown in  FIG.  3 B , the area of one of the openings  302  is smaller than the area of one of the light-emitting units  206  (e.g., the area of the bottom surface or top surface of one of the light-emitting units  206 ), and thus the mechanical property of the conductive electrode  210  may be further improved. 
     In some embodiments, as shown in  FIG.  3 C , a single bulk conductive electrode  210  including a plurality of openings  302  can be provided. In addition, the single conductive electrode  210  may cover a plurality of sub-pixels  212 . 
     In some embodiments, as shown in  FIG.  3 A,  3 B, and  3 C , the light-emitting units  206  are fully covered by the conductive electrodes  210 . 
       FIGS.  3 D and  3 E  illustrate some conductive electrodes  210  according to some embodiments of the present disclosure which also may avoid or reduce the formation of cracks during the step of forming a curved display device. 
     In some embodiments, as shown in  FIG.  3 D , a single conductive electrode  210  may include a plurality of openings  302  having different shapes or sizes to increase design flexibility. 
     In some embodiments, as shown in  FIG.  3 E , the conductive electrode  210  may have a partially undulating edge  210   a.  For example, the edge  210   a  of the conductive electrode  210  may include a substantially straight portion  210   a ′ and a wavy portion  210   a ″, where the wavy portion is provided at weak points that are prone to cracking. 
     In some other embodiments, the design of the conductive electrodes  210  (e.g., the wavy shape, and/or the opening therein) discussed above can be applied to a common electrode, a touch electrode, other conductive electrodes, or a combination thereof of a display device. The details will be discussed in the following paragraph. 
       FIG.  4 A  is a schematic cross-sectional of the display device  40  according to some embodiments of the present disclosure. The display device  40  can be used to form a curved display device (e.g., a curved display device with a side view the same as, or similar to the curved display devices  10  or  10 ′ discussed above). For example, the display device  40  can be bent to form a curved display device. 
     As shown in  FIG.  4 A , the display device  40  includes a substrate  400 . For example, the substrate  400  can be made of glass, polyimide, other applicable materials, or a combination thereof. A buffer layer  402  may be optionally formed on the substrate  400  to reduce the lattice mismatch. For example, the buffer layer  402  can be made of silicon oxide, silicon nitride, other applicable materials, or a combination thereof. A semiconductor layer  404  may be formed on the buffer layer  402 . For example, the semiconductor layer  404  may include one or more doped regions  404   a  which may serve as source/drain regions. A gate insulator  406  may be formed on the semiconductor layer  404 . For example, the gate insulator  406  may be made of silicon oxide, other applicable materials, or a combination thereof. One or more gate electrodes  408  may be formed on the gate insulator  406 , and a first insulating layer  410  (e.g., silicon oxide) may be formed on the one or more gate electrodes  408 . A second insulating layer  412  may be formed on the first insulating layer  410 . For example, the second insulating layer  412  may be made of a material (e.g., silicon nitride) that is different from the material of the first insulating layer  410 . A third insulating layer  414  may be formed on the second insulating layer  412 . For example, the third insulating layer  414  may be made of silicon nitride, organic materials (e.g., Acrylic based organic material), other applicable insulating materials, or a combination thereof. A pixel defining layer (PDL)  416  may be formed on the third insulating layer  414 . For example, the pixel defining layer  416  (e.g. an insulating layer) may be made of photosensitive polyimide, acrylic, siloxane, novolac materials, other applicable materials, or a combination thereof. A reflector  420  may be formed on the pixel defining layer  416 . As shown in  FIG.  4 A , the reflector  420  may extend from a top surface of the pixel defining layer  416  into the pixel defining layer  416  and the third insulating layer  414 . For example, the reflector  420  may be made of metal (e.g., Al or Ag), metal alloys (e.g., metal alloys of Al or Ag), other applicable materials, or a combination thereof. One or more light-emitting units  424  (e.g., light-emitting diodes) may be formed on the reflector  420 . As shown in  FIG.  4 A , a filling material may be formed on the reflector  420  and around the one or more light-emitting units  424 . For example, the filling material  422  may be made of organic material, anisotropic conductive film (ACF) bonding material, other applicable materials, or a combination thereof. In some embodiments, the filling material can include quantum dots therein. As shown in  FIG.  4 A , one or more conductive lines  418  may be formed on the pixel defining layer  416 . For example, the conductive lines  418  may also have a wavy shape and/or include one or more openings as do the conductive lines  208  discussed above. As shown in  FIG.  4 A , the display device  40  may also include a fourth insulating layer  426  formed on the conductive lines  418 , the light-emitting units  424 , and the pixel defining layer  416 . For example, the fourth insulating layer  426  may be made of an organic material, inorganic/organic stacked layer (e.g., SiNx/organic/SiNx stacked layer), other applicable insulating materials, or a combination thereof. As shown in  FIG.  4 A , a conductive electrode  428  which may be configured to electrically connect the conductive line  418  to the light-emitting unit  424  may be formed on the conductive lines  418 , the light-emitting units  424 , and the fourth insulating layer  426 . 
     As shown in  FIG.  4 A , one or more conductive structures  434  may be formed in the display device  40  to electrically connect different elements of the display device  40 . 
     In some embodiments, the conductive electrode  428  may include a common electrode, a touch electrode, or a combination thereof. As noted above, the design of the conductive electrodes  210  (e.g., the wavy shape, and/or the opening therein) discussed above can be applied to the conductive electrode  428  (e.g., a common electrode, a touch electrode, or a combination thereof), such that the formation of cracks during the step of forming a curved display device may be avoided or reduced. 
     In some embodiments, a single bulk conductive electrode  428  may simultaneously serve as a common electrode and a touch electrode, and thus the route for transmitting common signals and the route for transmitting touch signals may be the same. However, in other embodiments, as shown in  FIG.  4 B , two conductive electrodes  428   a  and  428   b  may respectively serve as a touch electrode and a common electrode, and thus the route for transmitting touch signals and the route for transmitting common signals may be different. 
     In some embodiments, the touch electrode and the common electrode may be formed in different layers. For example, as shown in  FIG.  4 C , one or more touch electrodes  432  can be formed on the common electrode  428 , and an insulating layer  430  may be formed between the one or more touch electrodes  432  and the common electrode  428 . In some embodiments, as shown in  FIG.  4 C , the one or more touch electrodes  432  and the light-emitting units  424  do not overlap, and thus a better device performance may be obtained. 
     Notably, more layers of conductive electrodes can be formed on the conductive electrode  428  according to, for example, the application of the display device. For example, more layers of touch electrodes can be formed on the common electrode  428  and the touch electrodes  432  of the display device illustrated in  FIG.  4 C . 
     In some embodiments, as shown in  FIG.  4 A , the insulating layer under the light-emitting units  424  (e.g., insulating layers  414 ) may include a recess or a trench  414   a  therein, which may further reduce the formation of cracks in the display device during the step of forming a curved display device. 
     It should be noted that the curved display devices formed of the display devices of the above embodiments may include technical features that are the same as or similar to the technical features of the display devices of the above embodiments. For example, the conductive electrodes may still have a wavy shape and/or include one or more openings in the curved display devices formed of the display devices of the above embodiments. These curved display devices are intended to be included within the scope of the present disclosure. 
     Third Embodiment 
       FIG.  5    is a schematic cross-sectional of the display device  50  according to Third Embodiment of the present disclosure. The display device  50  can be used to form a curved display device (e.g., a curved display device with a side view the same as, or similar to the curved display devices  10  or  10 ′ discussed above). For example, the display device  50  can be bent to form a curved display device. 
     The display device  50  may be similar to the display devices of the above embodiments (e.g., the display device  40 ), and the difference between the display device  50  and the display devices of the above embodiments will be discussed in the following paragraph. 
     As shown in  FIG.  5   , the pixel defining layer  416  may include a first portion  416   a  overlapping with the conductive line  418 , and a second portion  416   b  not overlapping with the conductive line  418 . As shown in  FIG.  5   , the second portion  416   b  of the pixel defining layer  416  is adjacent to the first portion  416   a  of the pixel defining layer  416  (e.g. an insulating layer). In some embodiments, a thickness T 1  of the first portion  416   a  can be greater than a thickness T 2  of the second portion  416   b  (e.g., a minimum thickness of the second portion  416   b ), which may improve the mechanical property of the display device  50  (e.g., avoiding or reducing the formation of cracks in the display device  50  during the step of bending the display device  50  to form a curved display device). 
     As shown in  FIG.  5   , the fourth insulating layer  426  may include a first portion  426   a  overlapping with the conductive electrode  428 , and a second portion  426   b  not overlapping with the conductive electrode  428 . As shown in  FIG.  5   , the second portion  426   b  of the fourth insulating layer  426  is adjacent to the first portion  426   a  of the fourth insulating layer  426 . In some embodiments, a thickness T 4  of the second portion  426   b  can be greater than a thickness T 3  of the first portion  426   a  (e.g., a minimum thickness of the first portion  426   a ), which may improve the mechanical property of the display device  50  (e.g., avoiding or reducing the formation of cracks in the display device  50  during the step of bending the display device  50  to form a curved display device). 
     It should be noted that the curved display devices formed of the display devices of the above embodiments may include technical features which are the same as or similar to the technical features of the display devices of the above embodiments (e.g., the technical features of the insulating layers discussed in paragraphs [0086] and [0087]). These curved display devices are intended to be included within the scope of the present disclosure. 
     Fourth Embodiment 
     Fourth Embodiment of the present disclosure also provides some display devices which may avoid or reduce the formation of cracks in the step of using these display devices to form curved display devices. 
     Referring to  FIG.  6 A , a schematic side view of the display device  60  according to Fourth Embodiment of the present disclosure is provided. Although only the substrate  200  and the light-emitting units (e.g., light-emitting units)  206   a  and  206   b  are shown in  FIG.  6 A  for the interest of simplicity, one skilled in the art can understand that additional layers and/or components discussed in the above embodiments may also be disposed in the display device  60 . For example, some insulating layers may be formed between the substrate  200  and the light-emitting units ( 206   a  and  206   b ) of the display device  60 , and one or more conductive electrodes may be formed on the light-emitting units  206   a  and  206   b.    
     For example, the display device  60  can be bent to form a curved display device (e.g., curved display device  10 ′ shown in  FIG.  1 B ). As shown in  FIG.  6 A , the display device  60  can include a portion  60   a  and a portion  60   b.  For example, the portion  60   a  can correspond to a curved portion of a curved display device (e.g., the curved portion  100 ′ of the curved display device  10 ′ illustrated in  FIG.  1 B ) formed of the display device  60 , and the portion  60   b  can correspond to a non-curved portion of the curved display device formed of the display device  60 . 
     In some embodiments, the dimension of one of the light-emitting units  206   a  in the portion  60   a  may be smaller than the dimension of one of the light-emitting units  206   b  in the portion  60   b,  which may avoid or reduce the formation of cracks in the step of using the display device  60  to form a curved display device. For example, the bottom surface area of one of the light-emitting units  206   a  may be smaller than the bottom surface area of one of the light-emitting units  206   b.  In some embodiments, the ratio of the bottom surface area of one of the light-emitting units  206   a  to the bottom surface area of one of the light-emitting units  206   b  may be 0.3 to 0.95. 
     In some embodiments, as shown in  FIG.  6 A , the density (e.g., number of light-emitting units per unit area) of the light-emitting units  206   a  in the portion  60   a  may be smaller than the density of the light-emitting units  206   b  in the portion  60   b,  which may avoid or reduce the formation of cracks in the step of using the display device  60  to form a curved display device. 
     Referring to  FIG.  6 B , a schematic side view of the display device  70  according to another embodiment of the present disclosure is provided. Similar to the display device  60 , the display device  70  also includes a portion  70   a  corresponding to the curved portion of the curved display device (e.g., the curved portion  100  of the curved display device  10  illustrated in  FIG.  1 A ) formed of the display device  70 , and a portion  70   b  corresponding to the non-curved portion of the curved display device formed of the display device  70 . 
     In some embodiments, the dimension of one of the light-emitting units  206   a  in the portion  70   a  may be smaller than the dimension of one of the light-emitting units  206   b  in the portion  70   b,  which may avoid or reduce the formation of cracks in the step of using the display device  70  to form a curved display device. For example, the bottom surface area of one of the light-emitting units  206   a  may be smaller than the bottom surface area of one of the light-emitting units  206   b.  In some embodiments, the ratio of the bottom surface area of one of the light-emitting units  206   a  to the bottom surface area of one of the light-emitting units  206   b  may be 0.3 to 0.95. 
     In some embodiments, as shown in  FIG.  6 B , the density (e.g., number of light-emitting units per unit area) of the light-emitting units  206   a  in portion  70   a  may be smaller than the density of the light-emitting units  206   b  in portion  70   b,  which may avoid or reduce the formation of cracks in the step of using the display device  70  to form a curved display device. 
     It should be noted that the curved display devices formed of the display devices of the above embodiments may include technical features which are the same as or similar to the technical features of the display devices of the above embodiments (e.g., the technical features of the light-emitting units discussed in paragraphs [0093]-[0094], and [0096]-[0097]). These curved display devices are intended to be included within the scope of the present disclosure. 
     Fifth Embodiment 
     Fifth Embodiment of the present disclosure also provides some display devices which may avoid or reduce the formation of cracks in the step of using these display devices to form curved display devices. 
     Referring to  FIG.  7 A , a schematic top view of the display device  80  according to Fifth Embodiment of the present disclosure is provided. Although only the substrate  800  and the conductive electrodes (or conductive lines)  802  are shown in  FIG.  7 A  for the interest of simplicity, one skilled in the art can understand that additional layers and/or components discussed in the above embodiments may also be disposed in the display device  80 . For example, some light-emitting units or insulating layers may be formed in the display device  80 . 
     For example, the display device  80  can be bent to form a curved display device (e.g., the curved display devices  10  or  10 ′ shown in  FIGS.  1 A and  1 B ). As shown in  FIG.  7 A , the display device  80  can include a portion  80   a  and a portion  80   b.  For example, the portion  80   a  can correspond to a curved portion of a curved display device (e.g., the curved portion  100 ′ of the curved display device  10 ′ illustrated in  FIG.  1 B ) formed of the display device  80 , and the portion  80   b  can correspond to a non-curved portion of the curved display device formed of the display device  80 . 
     As shown in  FIG.  7 A , the conductive electrode (or conductive line)  802  can include a neck portion  802   a  disposed in the portion  80   a  of the display device  80 , and a portion  802   b  disposed in the portion  80   b  of the display device  80 . For example, the portion  802   a  is narrower than the other portions of the conductive electrode (or conductive line)  802 . In some embodiments, a width W 2  of the portion  802   a  of the conductive electrode (or conductive line)  802  is smaller than a width W 1  of the portion  802   b  of the conductive electrode (or conductive line)  802 , which may avoid or reduce the formation of cracks in the step of using the display device  80  to form a curved display device. 
     In some embodiments, as shown in  FIG.  7 B , the conductive electrode (or conductive line)  802  can include one or more openings  804 . The density (e.g., number of openings per unit area) of the openings  804  in the portion  802   a  of the conductive electrode (or conductive line)  802  and the density of the openings  804  in the portion  802   b  of the conductive electrode (or conductive line)  802  may be different. For example, the density of the openings  804  in the portion  802   a  of the conductive electrode (or conductive line)  802  may be greater than the density of the openings  804  in the portion  802   b  of the conductive electrode (or conductive line)  802 , which may avoid or reduce the formation of cracks in the step of using the display device  80  to form a curved display device. 
     In some embodiments, as shown in  FIG.  7 C , the area of one of the openings  804  in the portion  802   a  of the conductive electrode  802  and the area of one of the openings  804  in the portion  802   b  of the conductive electrode (or conductive line)  802  may be different. For example, the area of one of the openings  804  in the portion  802   a  of the conductive electrode (or conductive line)  802  may be greater than the area of one of the openings  804  in the portion  802   b  of the conductive electrode (or conductive line)  802 , which may avoid or reduce the formation of cracks in the step of using the display device  80  to form a curved display device. 
     It should be noted that the curved display devices formed of the display devices of the above embodiments may include technical features which are the same as or similar to the technical features of the display devices of the above embodiments (e.g., the technical features of the conductive electrodes discussed in paragraphs [00103]-[00105]). These curved display devices are intended to be included within the scope of the present disclosure. 
     Understandably, a deposition process, a lithography process, an etching process, other applicable processes, or a combination thereof may be used to form the display devices of the above embodiments. 
     The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure. In addition, each claim can be an individual embodiment of the present disclosure, and the scope of the present disclosure includes the combinations of every claim and every embodiment of the present disclosure.