Patent Publication Number: US-2022238619-A1

Title: Display device

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims priority under 35 USC § 119 to Korean Patent Application No. 10-2021-0009419 filed on Jan. 22, 2021 in the Korean Intellectual Property Office (KIPO), the entire disclosure of which is incorporated by reference herein. 
     BACKGROUND 
     1. Field 
     The present inventive concept relates to display devices. More particularly, the present inventive concept relates to display devices that include pluralities of transistors. 
     2. Description of the Related Art 
     In general, a display device may include a light emitting element and a driving circuit for controlling an electrical signal applied to the light emitting element. The driving circuit may include a transistor, a capacitor, or the like. 
     The number of transistors electrically connected to one light emitting element is increasing in order to accurately control whether or not the light emitting element emits light and the degree of light emission. Accordingly, research for solving the problem of high integration and power consumption of the display device is being actively conducted. 
     SUMMARY 
     A display device according to an embodiment may include a first active layer disposed on a substrate, a scan line disposed on the first active layer, extending in a first direction, and including a first protruding portion protruding in a second direction crossing the first direction, a first compensation control line disposed on the first active layer, extending in the first direction, and spaced apart from the scan line in the second direction, and a second active layer disposed on the scan line and the first compensation control line, overlapping the scan line and the first compensation control line, and including a second protruding portion protruding in the first direction. The first protruding portion may be positioned outside the second active layer in the first direction in a plan view. 
     In an embodiment, the second protruding portion may be positioned outside the scan line in the second direction in the plan view. 
     In an embodiment, the first compensation control line may include a third protruding portion protruding in the second direction. The third protruding portion may be positioned outside the second active layer in the first direction in the plan view. 
     In an embodiment, the scan line and the second active layer may form a boosting capacitor in a region in which the scan line and the second active layer overlap each other. 
     A display device according to an embodiment may include a first active layer disposed on a substrate, a scan line disposed on the first active layer and extending in a first direction, a first compensation control line disposed on the first active layer, extending in the first direction, and spaced apart from the scan line in a second direction crossing the first direction, and a second active layer disposed on the scan line and the first compensation control line and overlapping the scan line and the first compensation control line. The scan line and the second active layer may form a boosting capacitor in a region in which the scan line and the second active layer overlap each other. A planar area of the boosting capacitor may be determined by a width of the second active layer in the first direction and a width of the scan line in the second direction in the region in which the scan line and the second active layer overlap each other. 
     In an embodiment, the first compensation control line and the second active layer may form a compensation transistor capacitor in a region in which the first compensation control line and the second active layer overlap each other. A planar area of the compensation transistor capacitor may be determined by a width of the second active layer in the first direction and a width of the first compensation control line in the second direction in the region in which the first compensation control line and the second active layer overlap each other. 
     In an embodiment, the scan line may be disposed between the first active layer and the first compensation control line. 
     In an embodiment, the scan line may be disposed on the same layer as the first compensation control line. 
     In an embodiment, the display device may further include a first conductive pattern disposed on a same layer as the scan line. The first active layer and the first conductive pattern may form a driving transistor. 
     In an embodiment, the driving transistor may be a p-channel metal oxide semiconductor (PMOS) transistor. 
     In an embodiment, the display device may further include a second compensation control line disposed on the second active layer, extending in the first direction, and overlapping the first compensation control line. The first compensation control line, the second active layer, and the second compensation control line may form a compensation transistor for compensating a threshold voltage of the driving transistor. 
     In an embodiment, the compensation transistor may be an n-channel metal oxide semiconductor (NMOS) transistor. 
     In an embodiment, the display device may further include a first gate connection electrode disposed on the second compensation control line and electrically connecting the first conductive pattern and the second active layer. 
     In an embodiment, the display device may further include a data line disposed on the first gate connection electrode, extending in the second direction, and transmitting a data voltage applied to the first conductive pattern through the driving transistor and the compensation transistor. 
     In an embodiment, the display device may further include a first electrode disposed on the data line, an emission layer disposed on the first electrode, and a second electrode disposed on the emission layer. The first electrode, the emission layer, and the second electrode may form a light emitting element emitting a light based on a driving current generated by the driving transistor. 
     In an embodiment, the display device may further include a first bridge line disposed on the same layer as the first gate connection electrode and extending in the first direction. 
     In an embodiment, the display device may further include a second bridge line disposed on the same layer as the data line and extending in the second direction. 
     In an embodiment, the display device may further include a second gate connection electrode disposed on the same layer as the second compensation control line and connecting the first conductive pattern and the first gate connection electrode. 
     In an embodiment, the display device may further include a second conductive pattern disposed on the same layer as the first compensation control line and overlapping the first conductive pattern. The first conductive pattern and the second conductive pattern may form a storage capacitor in a region in which the first conductive pattern and the second conductive pattern overlap each other. 
     In an embodiment, the display device may further include a lower wiring disposed between the substrate and the first active layer. 
     In an embodiment, a material of the first active layer may be different from a material of the second active layer. 
     In an embodiment, the first active layer may include at least one of amorphous silicon and polycrystalline silicon. The second active layer may include an oxide semiconductor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Illustrative, non-limiting embodiments will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings. 
         FIG. 1  is a plan view illustrating a display device according to an embodiment. 
         FIG. 2  is a circuit diagram illustrating a pixel of the display device in  FIG. 1 . 
         FIG. 3  is a plan view illustrating a first active layer of a display device according to an embodiment. 
         FIG. 4  is a plan view illustrating a first conductive layer of a display device according to an embodiment. 
         FIG. 5  is a plan view illustrating a second conductive layer of a display device according to an embodiment. 
         FIG. 6  is a plan view illustrating a second active layer of a display device according to an embodiment. 
         FIG. 7  is a plan view illustrating a third conductive layer of a display device according to an embodiment. 
         FIG. 8  is a plan view illustrating a fourth conductive layer of a display device according to an embodiment. 
         FIG. 9  is a plan view illustrating a fifth conductive layer of a display device according to an embodiment. 
         FIG. 10  is a cross-sectional view illustrating the display device taken along a line I-I′ in  FIG. 9 . 
         FIG. 11  is a layout view illustrating a region A in  FIG. 6 . 
         FIG. 12  is a plan view illustrating a lower wiring of a display device according to an embodiment. 
         FIG. 13  is a cross-sectional view illustrating the display device taken along the line I-I′ in  FIG. 9 . 
         FIG. 14  is a plan view illustrating a first active layer of a display device according to an embodiment. 
         FIG. 15  is a plan view illustrating a first conductive layer of a display device according to an embodiment. 
         FIG. 16  is a plan view illustrating a second conductive layer of a display device according to an embodiment. 
         FIG. 17  is a plan view illustrating a second active layer of a display device according to an embodiment. 
         FIG. 18  is a plan view illustrating a third conductive layer of a display device according to an embodiment. 
         FIG. 19  is a plan view illustrating a fourth conductive layer of a display device according to an embodiment. 
         FIG. 20  is a plan view illustrating a fifth conductive layer of a display device according to an embodiment. 
         FIG. 21  is a layout view illustrating a display device according to an embodiment. 
         FIG. 22  is a cross-sectional view illustrating an example of the display device taken along a line II-II′ in  FIG. 21 . 
         FIG. 23  is a cross-sectional view illustrating another example of the display device taken along the line II-II′ in  FIG. 21 . 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Embodiments provide a display device for preventing occurrence of stains. 
     In the display device according to the embodiments, the planar area of the boosting capacitor and the planar area of the compensation transistor capacitor may be determined by the width of the second active layer in the first direction, or the scan line and the first compensation control line may be disposed on the same layer, so that deviation of a kickback voltage due to the boosting capacitor and the compensation transistor capacitor may decrease. Accordingly, the occurrence of stains of the display device may be reduced or substantially prevented. 
     Hereinafter, display devices in accordance with embodiments will be explained in detail with reference to the accompanying drawings. 
       FIG. 1  is a plan view illustrating a display device according to an embodiment. 
     Referring to  FIG. 1 , a display device may include a plurality of pixels PX. Each pixel PX refers to a single area defined by partitioning a display area in a plan view for color display, and one pixel PX may display one predetermined basic color. In other words, one pixel PX may be a minimum unit capable of displaying colors independent from other pixels PX. The pixels PX may be arranged along a first direction DR 1  and a second direction DR 2  crossing the first direction DR 1 . In an embodiment, the first direction DR 1  and the second direction DR 2  may be a pixel row direction and a pixel column direction, respectively. In another embodiment, the first direction DR 1  and the second direction DR 2  may be the pixel column direction and the pixel row direction, respectively. 
       FIG. 2  is a circuit diagram illustrating the pixel PX of the display device in  FIG. 1 . 
     Referring to  FIG. 2 , the pixel PX may include a plurality of transistors, a storage capacitor CST, a boosting capacitor CBT, and a light emitting element EL. In an embodiment, the plurality of transistors may include a driving transistor T 1 , a switching transistor T 2 , a compensation transistor T 3 , a first initialization transistor T 4 , a first emission control transistor T 5 , a second emission control transistor T 6 , and a second initialization transistor T 7 . However, the present inventive concept is not limited thereto, and in another embodiment, the plurality of transistors may include 2 to 6 or 8 or more transistors. 
     A gate electrode of the driving transistor T 1  may be connected to a first node N 1 . A first electrode of the driving transistor T 1  may be connected to a second node N 2 , and a second electrode of the driving transistor T 1  may be connected to a third node N 3 . The driving transistor T 1  may generate a driving current based on a voltage between the first node N 1  and the second node N 2 . 
     A gate electrode of the switching transistor T 2  may receive a scan signal GW. A first electrode of the switching transistor T 2  may receive a data voltage DATA, and a second electrode of the switching transistor T 2  may be connected to the second node N 2 . The switching transistor T 2  may transmit the data voltage DATA to the second node N 2  based on the scan signal GW. 
     A gate electrode of the compensation transistor T 3  may receive a compensation control signal GC. A first electrode of the compensation transistor T 3  may be connected to the third node N 3 , and a second electrode of the compensation transistor T 3  may be connected to the first node N 1 . The compensation transistor T 3  may compensate a threshold voltage of the driving transistor T 1  by connecting the first node N 1  and the third node N 3  based on the compensation control signal GC. 
     A gate electrode of the first initialization transistor T 4  may receive a first initialization control signal GI. A first electrode of the first initialization transistor T 4  may receive a first initialization voltage VINT, and a second electrode of the first initialization transistor T 4  may be connected to the first node N 1 . The first initialization transistor T 4  may initialize the gate electrode of the driving transistor T 1  by transmitting the first initialization voltage VINT to the first node N 1  based on the first initialization control signal GI. 
     A gate electrode of the first emission control transistor T 5  may receive an emission control signal EM. A first electrode of the first emission control transistor T 5  may receive a driving voltage ELVDD, and a second electrode of the first emission control transistor T 5  may be connected to the second node N 2 . 
     A gate electrode of the second emission control transistor T 6  may receive the emission control signal EM. A first electrode of the second emission control transistor T 6  may be connected to the third node N 3 , and a second electrode of the second emission control transistor T 6  may be connected to a fourth node N 4 . The first emission control transistor T 5  and the second emission control transistor T 6  may transmit the driving current generated by the driving transistor T 1  to the light emitting element EL based on the emission control signal EM. 
     A gate electrode of the second initialization transistor T 7  may receive a second initialization control signal GB. A first electrode of the second initialization transistor T 7  may receive a second initialization voltage AINT, and a second electrode of the second initialization transistor T 7  may be connected to the fourth node N 4 . In an embodiment, when the pixel PX is included in an N-th pixel row, the second initialization control signal GB may be a scan signal GW applied to an (N+1)-th pixel row. The second initialization transistor T 7  may initialize the light emitting element EL by transmitting the second initialization voltage AINT to the fourth node N 4  based on the second initialization control signal GB. 
     In an embodiment, each of the driving transistor T 1 , the switching transistor T 2 , the first emission control transistor T 5 , the second emission control transistor T 6 , and the second initialization transistor T 7  may be a transistor having a single gate structure, and each of the compensation transistor T 3  and the first initialization transistor T 4  may be a transistor having a double gate structure. In such an embodiment, the gate electrode of each of the compensation transistor T 3  and the first initialization transistor T 4  may include a lower gate electrode and an upper gate electrode, and the lower gate electrode and the upper gate electrode may be electrically connected. 
     In an embodiment, an active layer of each of the driving transistor T 1 , the switching transistor T 2 , the first emission control transistor T 5 , the second emission control transistor T 6 , and the second initialization transistor T 7  may be formed of amorphous silicon or polycrystalline silicon, and an active layer of each of the compensation transistor T 3  and the first initialization transistor T 4  may be formed of an oxide semiconductor. In an embodiment, each of the driving transistor T 1 , the switching transistor T 2 , the first emission control transistor T 5 , the second emission control transistor T 6 , and the second initialization transistor T 7  may be a p-channel metal oxide semiconductor (PMOS) transistor, and each of the compensation transistor T 3  and the first initialization transistor T 4  may be an n-channel metal oxide semiconductor (NMOS) transistor. 
     A first electrode of the storage capacitor CST may receive the driving voltage ELVDD, and a second electrode of the storage capacitor CST may be connected to the first node N 1 . The storage capacitor CST may maintain a voltage between the first node N 1  and the second node N 2  when the switching transistor T 2  is turned off, so that the light emitting element EL may emit light. 
     A first electrode of the boosting capacitor CBT may receive the scan signal GW, and a second electrode of the boosting capacitor CBT may be connected to the first node N 1 . When the scan signal GW is at a voltage level which turns off the switching transistor T 2 , the boosting capacitor CBT may increase the voltage of the first node N 1  to reduce a voltage for displaying black (black voltage). Accordingly, power consumption of the pixel PX may be reduced. 
     A first electrode of the light emitting element EL may be connected to the fourth node N 4 , and a second electrode of the light emitting element EL may receive a common voltage ELVSS. In an embodiment, a voltage level of the common voltage ELVSS may be lower than a voltage level of the driving voltage ELVDD. The light emitting element EL may emit light based on the driving current. 
       FIG. 3  is a plan view illustrating a first active layer ACT 1  of a display device according to an embodiment.  FIG. 4  is a plan view illustrating a first conductive layer  110  of a display device according to an embodiment.  FIG. 5  is a plan view illustrating a second conductive layer  120  of a display device according to an embodiment.  FIG. 6  is a plan view illustrating a second active layer ACT 2  of a display device according to an embodiment.  FIG. 7  is a plan view illustrating a third conductive layer  130  of a display device according to an embodiment.  FIG. 8  is a plan view illustrating a fourth conductive layer  140  of a display device according to an embodiment.  FIG. 9  is a plan view illustrating a fifth conductive layer  150  of a display device according to an embodiment.  FIG. 10  is a cross-sectional view illustrating the display device taken along a line I-I′ in  FIG. 9 . 
     Referring to  FIGS. 3, 4, 5, 6, 7, 8, 9, and 10 , a display device may include a first active layer ACT 1 , a first conductive layer  110 , a second conductive layer  120 , a second active layer ACT 2 , a third conductive layer  130 , a fourth conductive layer  140 , a fifth conductive layer  150 , a first electrode  160 , an emission layer  170 , and a second electrode  180 , which are disposed on a substrate SUB. 
     The substrate SUB may be an insulating substrate including glass, quartz, plastic, or the like. In an embodiment, the substrate SUB may include a first flexible layer, a first barrier layer disposed on the first flexible layer, a second flexible layer disposed on the first barrier layer, and a second barrier layer disposed on the second flexible layer. The first flexible layer and the second flexible layer may include an organic insulation material such as polyimide (PI) or the like, and the first barrier layer and the second barrier layer may include an inorganic insulation material such as silicon oxide, silicon nitride, amorphous silicon, or the like. 
     The first active layer ACT 1  may be disposed on the substrate SUB. 
     A buffer layer BUF may be disposed between the substrate SUB and the first active layer ACT 1 . The buffer layer BUF may block diffusion of impurities such as oxygen, moisture, etc. through the substrate SUB to above the substrate SUB. Further, the buffer layer BUF may provide a planarized upper surface on the substrate SUB. The buffer layer BUF may include an inorganic insulation material such as silicon oxide, silicon nitride, silicon oxynitride, or the like. Alternatively, the buffer layer BUF may be omitted. 
     The first conductive layer  110  may be disposed on the first active layer ACT 1 . The first conductive layer  110  may include a conductive material such as molybdenum (Mo), copper (Cu), aluminum (Al), titanium (Ti), or the like. 
     The first conductive layer  110  may include a scan line  111 , an emission control line  112 , and a first conductive pattern  113 . The scan line  111  may extend in the first direction DR 1 . The emission control line  112  may be spaced apart from the scan line  111 , and may extend in the first direction DR 1 . The first conductive pattern  113  may be positioned between the scan line  111  and the emission control line  112 . 
     A first portion of the scan line  111  overlapping the first active layer ACT 1  may form the gate electrode of the switching transistor T 2 , and a second portion of the scan line  111  overlapping the first active layer ACT 1  may form the gate electrode of the second initialization transistor T 7 . In an embodiment, when the pixel PX is included in the N-th pixel row, the second portion of the scan line  111  may form the gate electrode of the second initialization transistor T 7  of the pixel included in an (N−1)-th pixel row. A portion of the first active layer ACT 1  overlapping the gate electrode of the switching transistor T 2  may be a channel region of the switching transistor T 2 , and a portion of the first active layer ACT 1  overlapping the gate electrode of the second initialization transistor T 7  may be a channel region of the second initialization transistor T 7 . Accordingly, the first active layer ACT 1  and the first portion of the scan line  111  may form the switching transistor T 2 , and the first active layer ACT 1  and the second portion of the scan line  111  may form the second initialization transistor T 7 . 
     A first portion of the emission control line  112  overlapping the first active layer ACT 1  may form the gate electrode of the first emission control transistor T 5 , and a second portion of the emission control line  112  overlapping the first active layer ACT 1  may form the gate electrode of the second emission control transistor T 6 . A portion of the first active layer ACT 1  overlapping the gate electrode of the first emission control transistor T 5  may be a channel region of the first emission control transistor T 5 , and a portion of the first active layer ACT 1  overlapping the gate electrode the second emission control transistor T 6  may be a channel region of the second emission control transistor T 6 . Accordingly, the first active layer ACT 1  and the first portion of the emission control line  112  may form the first emission control transistor T 5 , and the first active layer ACT 1  and the second portion of the emission control line  112  may form the second emission control transistor T 6 . 
     A portion of the first conductive pattern  113  overlapping the first active layer ACT 1  may form the gate electrode of the driving transistor T 1 . A portion of the first active layer ACT 1  overlapping the gate electrode of the driving transistor T 1  may be a channel region of the driving transistor T 1 . Accordingly, the first active layer ACT 1  and the portion of the first conductive pattern  113  may form the driving transistor T 1 . 
     A first insulation layer  101  may be disposed between the first active layer ACT 1  and the first conductive layer  110 . The first insulation layer  101  may include an inorganic insulation material such as silicon oxide, silicon nitride, silicon oxynitride, or the like. 
     The second conductive layer  120  may be disposed on the first conductive layer  110 . The second conductive layer  120  may include a conductive material such as molybdenum (Mo), copper (Cu), aluminum (Al), titanium (Ti), or the like. 
     The second conductive layer  120  may include a first compensation control line  121 , a first initialization control line  122 , a second conductive pattern  123 , and a first initialization voltage line  124 . The first compensation control line  121  may extend in the first direction DR 1 . The first initialization control line  122  may be spaced apart from the first compensation control line  121 , and may extend in the first direction DR 1 . The second conductive pattern  123  may be spaced apart from the first compensation control line  121 . The first initialization voltage line  124  may be spaced apart from the first initialization control line  122 , and may extend in the first direction DR 1 . 
     The second conductive pattern  123  may overlap the first conductive pattern  113 . The first conductive pattern  113  and the second conductive pattern  123  may form the storage capacitor CST in a region in which the first conductive pattern  113  and the second conductive pattern  123  overlap each other. 
     A second insulation layer  102  may be disposed between the first conductive layer  110  and the second conductive layer  120 . The second insulation layer  102  may include an inorganic insulation material such as silicon oxide, silicon nitride, silicon oxynitride, or the like. 
     The second active layer ACT 2  may be disposed on the second conductive layer  120 . The second active layer ACT 2  may not overlap the first active layer ACT 1 . A material of the first active layer ACT 1  may be different from a material of the second active layer ACT 2 . In an embodiment, the first active layer ACT 1  may include at least one of amorphous silicon and polycrystalline silicon, and the second active layer ACT 2  may include an oxide semiconductor. However, the present inventive concept is not limited thereto, and in another embodiment, the first active layer ACT 1  may include an oxide semiconductor, and the second active layer ACT 2  may include at least one of amorphous silicon and polycrystalline silicon. 
     A third insulation layer  103  may be disposed between the second conductive layer  120  and the second active layer ACT 2 . The third insulation layer  103  may include an inorganic insulation material such as silicon oxide, silicon nitride, silicon oxynitride, or the like. 
     The third conductive layer  130  may be disposed on the second active layer ACT 2 . The third conductive layer  130  may include a conductive material such as molybdenum (Mo), copper (Cu), aluminum (Al), titanium (Ti), or the like. 
     The third conductive layer  130  may include a second compensation control line  131  and a second initialization control line  132 . The second compensation control line  131  may extend in the first direction DR 1 . The second initialization control line  132  may be spaced apart from the second compensation control line  131 , and may extend in the first direction DR 1 . The second compensation control line  131  and the second initialization control line  132  may overlap the first compensation control line  121  and the first initialization control line  122 , respectively. 
     A portion of the first compensation control line  121  overlapping the second active layer ACT 2  may form a lower gate electrode of the compensation transistor T 3 , and a portion of the second compensation control line  131  overlapping the second active layer ACT 2  may form an upper gate electrode of the compensation transistor T 3 . A portion of the second active layer ACT 2  overlapping the lower gate electrode and the upper gate electrode of the compensation transistor T 3  may be a channel region of the compensation transistor T 3 . Accordingly, the portion of the first compensation control line  121 , the second active layer ACT 2 , and the portion of the second compensation control line  131  may form the compensation transistor T 3 . The compensation transistor T 3  may be a transistor having a double gate structure. 
     A portion of the first initialization control line  122  overlapping the second active layer ACT 2  may form a lower gate electrode of the first initialization transistor T 4 , and a portion of the second initialization control line  132  overlapping the second active layer ACT 2  may form an upper gate electrode of the first initialization transistor T 4 . A portion of the second active layer ACT 2  overlapping the lower gate electrode and the upper gate electrode of the first initialization transistor T 4  may be a channel region of the first initialization transistor T 4 . Accordingly, the portion of the first initialization control line  122 , the second active layer ACT 2 , and the portion of the second initialization control line  132  may form the first initialization transistor T 4 . The first initialization transistor T 4  may be a transistor having a double gate structure. 
     A fourth insulation layer  104  may be disposed between the second active layer ACT 2  and the third conductive layer  130 . The fourth insulation layer  104  may include an inorganic insulation material such as silicon oxide, silicon nitride, silicon oxynitride, or the like. 
     The fourth conductive layer  140  may be disposed on the third conductive layer  130 . The fourth conductive layer  140  may include a conductive material such as aluminum (Al), titanium (Ti), copper (Cu), or the like. In an embodiment, the fourth conductive layer  140  may have a multilayer structure including a titanium layer, an aluminum layer, and a titanium layer, which are stacked. 
     The fourth conductive layer  140  may include a second initialization voltage line  141 , a first gate connection electrode  142 , an active connection electrode  143 , a data connection electrode  144 , a driving voltage connection electrode  145 , a first light emitting element connection electrode  146 , and a first initialization voltage connection electrode  147 . The second initialization voltage line  141  may extend in the first direction DR 1 . The second initialization voltage line  141  may be connected to the first active layer ACT 1  through a contact hole. Specifically, the second initialization voltage line  141  may be connected to the first electrode of the second initialization transistor T 7 . 
     The first gate connection electrode  142  may be spaced apart from the second initialization voltage line  141 . The first gate connection electrode  142  may be connected to the first conductive pattern  113  and the second active layer ACT 2  through contact holes, respectively. Specifically, the first gate connection electrode  142  may connect the gate electrode of the driving transistor T 1 , the second electrode of the compensation transistor T 3 , and the second electrode of the first initialization transistor T 4 . 
     The active connection electrode  143  may be spaced apart from the first gate connection electrode  142 . The active connection electrode  143  may be connected to the first active layer ACT 1  and the second active layer ACT 2  through contact holes, respectively. Specifically, the active connection electrode  143  may connect the second electrode of the driving transistor T 1 , the first electrode of the compensation transistor T 3 , and the first electrode of the second emission control transistor T 6 . 
     The data connection electrode  144  may be spaced apart from the active connection electrode  143 . The data connection electrode  144  may be connected to the first active layer ACT 1  through a contact hole. Specifically, the data connection electrode  144  may be connected to the first electrode of the switching transistor T 2 . 
     The driving voltage connection electrode  145  may be spaced apart from the data connection electrode  144 . The driving voltage connection electrode  145  may be connected to the first active layer ACT 1  and the second conductive pattern  123  through contact holes, respectively. Specifically, the driving voltage connection electrode  145  may be connected to the first electrode of the first emission control transistor T 5  and the first electrode of the storage capacitor CST. 
     The first light emitting element connection electrode  146  may be spaced apart from the driving voltage connection electrode  145 . The first light emitting element connection electrode  146  may be connected to the first active layer ACT 1  through a contact hole. Specifically, the first light emitting element connection electrode  146  may be connected to the second electrode of the second emission control transistor T 6 . 
     The first initialization voltage connection electrode  147  may be spaced apart from the first light emitting element connection electrode  146 . The first initialization voltage connection electrode  147  may be connected to the first initialization voltage line  124  and the second active layer ACT 2  through contact holes, respectively. Specifically, the first initialization voltage connection electrode  147  may be connected to the first electrode of the first initialization transistor T 4 . 
     A fifth insulation layer  105  may be disposed between the third conductive layer  130  and the fourth conductive layer  140 . The fifth insulation layer  105  may include an inorganic insulation material such as silicon oxide, silicon nitride, silicon oxynitride, etc. and/or an organic insulation material such as polyimide (PI), etc. 
     The fifth conductive layer  150  may be disposed on the fourth conductive layer  140 . The fifth conductive layer  150  may include a conductive material such as aluminum (Al), titanium (Ti), copper (Cu), or the like. In an embodiment, the fifth conductive layer  150  may have a multilayer structure including a titanium layer, an aluminum layer, and a titanium layer, which are stacked. 
     The fifth conductive layer  150  may include a data line  151 , a driving voltage line  152 , and a second light emitting element connection electrode  153 . The data line  151  may extend in the second direction DR 2 . The data line  151  may be connected to the data connection electrode  144  through a contact hole. Accordingly, the data line  151  may be connected to the first electrode of the switching transistor T 2  by the data connection electrode  144 . 
     The driving voltage line  152  may be spaced apart from the data line  151 , and may extend in the second direction DR 2 . The driving voltage line  152  may be connected to the driving voltage connection electrode  145  through a contact hole. Accordingly, the driving voltage line  152  may be connected to the first electrode of the first emission control transistor T 5  and the first electrode of the storage capacitor CST by the driving voltage connection electrode  145 . 
     The second light emitting element connection electrode  153  may be spaced apart from the driving voltage line  152 . The second light emitting element connection electrode  153  may be connected to the first light emitting element connection electrode  146  through a contact hole. 
     A sixth insulation layer  106  may be disposed between the fourth conductive layer  140  and the fifth conductive layer  150 . The sixth insulation layer  106  may include an inorganic insulation material such as silicon oxide, silicon nitride, silicon oxynitride, etc. and/or an organic insulation material such as polyimide (PI), etc. 
     The first electrode  160  may be disposed on the fifth conductive layer  150 . The first electrode  160  may include a conductive material such as a metal, an alloy, a transparent conductive oxide, or the like. For example, the first electrode  160  may include silver (Ag), indium tin oxide (ITO), or the like. In an embodiment, the first electrode  160  may have a multilayer structure including an indium tin oxide layer, a silver layer, and an indium tin oxide layer, which are stacked. 
     The first electrode  160  may be connected to the second light emitting element connection electrode  153  through a contact hole. Accordingly, the first electrode  160  may be connected to the second electrode of the second emission control transistor T 6  by the first light emitting element connection electrode  146  and the second light emitting element connection electrode  153 . 
     A seventh insulation layer  107  may be disposed between the fifth conductive layer  150  and the first electrode  160 . The seventh insulation layer  107  may include an inorganic insulation material such as silicon oxide, silicon nitride, silicon oxynitride, etc. and/or an organic insulation material such as polyimide (PI), etc. 
     An eighth insulation layer  108  may be disposed on the first electrode  160 . The eighth insulation layer  108  may cover the first electrode  160 , and may be disposed on the seventh insulation layer  107 . The eighth insulation layer  108  may have a pixel opening exposing at least a portion of the first electrode  160 . In an embodiment, the pixel opening may expose a central portion of the first electrode  160 , and the eighth insulation layer  108  may cover a peripheral portion of the first electrode  160 . The eighth insulation layer  108  may include an organic insulation material such as polyimide (PI) or the like. 
     The emission layer  170  may be disposed on the first electrode  160 . The emission layer  170  may be disposed on the first electrode  160  exposed by the pixel opening. The emission layer  170  may include at least one of an organic light emitting material and a quantum dot. 
     In an embodiment, the organic light emitting material may include a low molecular weight organic compound or a high molecular weight organic compound. For example, the low molecular weight organic compound may include copper phthalocyanine, N,N′-diphenylbenzidine, tris-(8-hydroxyquinoline)aluminum, or the like, and the high molecular organic compound may include poly(3,4-ethylenedioxythiophene), polyaniline, polyphenylenevinylene, polyfluorene, or the like. 
     In an embodiment, the quantum dot may include a core including a group II-VI compound, a group III-V compound, a group IV-VI compound, a group IV element, a group IV compound, and combinations thereof. In an embodiment, the quantum dot may have a core-shell structure including a core and a shell surrounding the core. The shell may serve as a protective layer for maintaining semiconductor properties by preventing chemical modification of the core, and as a charging layer for imparting electrophoretic properties to the quantum dot. 
     The second electrode  180  may be disposed on the emission layer  170 . In an embodiment, the second electrode  180  may also be disposed on the eighth insulation layer  108 . The second electrode  180  may include a conductive material such as a metal, an alloy, a transparent conductive oxide, or the like. For example, the second electrode  180  may include aluminum (Al), platinum (Pt), silver (Ag), magnesium (Mg), gold (Au), chromium (Cr), tungsten (W), titanium (Ti), or the like. The first electrode  160 , the emission layer  170 , and the second electrode  180  may form the light emitting element EL. 
       FIG. 11  is a layout view illustrating a region A in  FIG. 6 .  FIG. 11  illustrates only the scan line  111 , the first compensation control line  121 , and the second active layer ACT 2  among the components disposed in the region A. 
     Referring to  FIGS. 3, 4, 5, 6, and 11 , the first compensation control line  121  may be disposed on the scan line  111 . In other words, the scan line  111  may be disposed between the first active layer ACT 1  and the first compensation control line  121 . The first compensation control line  121  may be spaced apart from the scan line  111  in the second direction DR 2  in a plan view. 
     The second active layer ACT 2  may be disposed on the scan line  111  and the first compensation control line  121 . The second active layer ACT 2  may overlap the scan line  111  and the first compensation control line  121 . 
     The scan line  111  and the second active layer ACT 2  may form the boosting capacitor CBT in a region in which the scan line  111  and the second active layer ACT 2  overlap each other. A planar area of the boosting capacitor CBT may be determined by a width W 1  of the second active layer ACT 2  in the first direction DR 1  and a width W 2  of the scan line  111  in the second direction DR 2  in the region in which the scan line  111  and the second active layer ACT 2  overlap each other. Specifically, the region, in which the scan line  111  and the second active layer ACT 2  overlap each other, may have a substantially rectangular shape. A first side of the rectangular shape may correspond to the width W 1  of the second active layer ACT 2  in the first direction DR 1 , and a second side of the rectangular shape perpendicular to the first side may correspond to the width W 2  of the scan line  111  in the second direction DR 2 . 
     The scan line  111  may include a first protruding portion PP 1  protruding in the second direction DR 2 . Specifically, the first protruding portion PP 1  may be defined as a portion of the scan line  111  which protrudes in the second direction DR 2  or in a direction opposite to the second direction DR 2 . The first protruding portion PP 1  may be positioned outside the second active layer ACT 2  in the first direction DR 1  in a plan view. Accordingly, a width of the boosting capacitor CBT in the first direction DR 1  may be determined by the width W 1  of the second active layer ACT 2  in the first direction DR 1  in the region in which the scan line  111  and the second active layer ACT 2  overlap each other. 
     The second active layer ACT 2  may include a second protruding portion PP 2  protruding in the first direction DR 1 . Specifically, the second protruding portion PP 2  may be defined as a portion of the second active layer ACT 2  which protrudes in the first direction DR 1  or in a direction opposite to the first direction DR 1 . The second protruding portion PP 2  may be positioned outside the scan line  111  in the second direction DR 2  in a plan view. Accordingly, a width of the boosting capacitor CBT in the second direction DR 2  may be determined by the width W 2  of the scan line  111  in the second direction DR 2  in the region in which the scan line  111  and the second active layer ACT 2  overlap each other. 
     The first compensation control line  121  and the second active layer ACT 2  may form a compensation transistor capacitor T 3 C in a region in which the first compensation control line  121  and the second active layer ACT 2  overlap each other. The compensation transistor capacitor T 3 C may be an internal capacitor of the compensation transistor T 3 . A planar area of the compensation transistor capacitor T 3 C may be determined by a width W 3  of the second active layer ACT 2  in the first direction DR 1  and a width W 4  of the first compensation control line  121  in the second direction DR 2  in the region in which the first compensation control line  121  and the second active layer ACT 2  overlap each other. Specifically, the region, in which the first compensation control line  121  and the second active layer ACT 2  overlap each other, may have a substantially rectangular shape. A first side of the rectangular shape may correspond to the width W 3  of the second active layer ACT 2  in the first direction DR 1 , and a second side of the rectangular shape perpendicular to the first side may correspond to the width W 4  of the first compensation control line  121  in the second direction DR 2 . 
     The first compensation control line  121  may include a third protruding portion PP 3  protruding in the second direction DR 2 . Specifically, the third protruding portion PP 3  may be a portion of the first compensation control line  121  which protrudes in the second direction DR 2  or in a direction opposite to the second direction DR 2 . The third protruding portion PP 3  may be positioned outside the second active layer ACT 2  in the first direction DR 1  in a plan view. Accordingly, a width of the compensation transistor capacitor T 3 C in the first direction DR 1  may be determined by the width W 3  of the second active layer ACT 2  in the first direction DR 1  in the region in which the first compensation control line  121  and the second active layer ACT 2  overlap each other. 
     The boosting capacitor CBT and the compensation transistor capacitor T 3 C induce a kickback voltage of the gate electrode of the driving transistor T 1 , and the boosting capacitor CBT and the compensation transistor capacitor T 3 C may induce kickback voltages of different polarities. The kickback voltage refers to an unintended voltage caused by capacitance between overlapping conductive layers. For example, the boosting capacitor CBT may induce a positive (+) kickback voltage, and the compensation transistor capacitor T 3 C may induce a negative (−) kickback voltage. Further, a capacitance of the boosting capacitor CBT may be proportional to the planar area of the boosting capacitor CBT, and a capacitance of the compensation transistor capacitor T 3 C may be proportional to the planar area of the compensation transistor capacitor T 3 C. 
     In the prior art, a width of the compensation transistor capacitor T 3 C in the first direction DR 1  may be determined by the second active layer ACT 2 , however, a width of the boosting capacitor CBT in the first direction DR 1  may be determined by the scan line  111  or by a combination of the scan line  111  and the second active layer ACT 2 . Accordingly, in the prior art, the correlation between the planar area of the boosting capacitor CBT and the planar area of the compensation transistor capacitor T 3 C may be relatively low, and accordingly, the deviation of the kickback voltage may increase. When the deviation of the kickback voltage increases, stains may occur in the display device. When the deviation of the kickback voltage increases, a difference between luminances of the pixels PX may occur, and the difference between the luminances of the pixels PX may be recognized as the stains. 
     In the present inventive concept, the width of the boosting capacitor CBT in the first direction DR 1  and the width of the compensation transistor capacitor T 3 C in the first direction DR 1  may be determined by the second active layer ACT 2 . Accordingly, in the present inventive concept, the correlation between the planar area of the boosting capacitor CBT and the planar area of the compensation transistor capacitor T 3 C may be relatively high, and accordingly, the deviation of the kickback voltage may be reduced. Accordingly, occurrence of stains in the display device may be reduced or substantially prevented. 
       FIG. 12  is a plan view illustrating a lower wiring of a display device according to an embodiment.  FIG. 13  is a cross-sectional view illustrating the display device taken along the line I-I′ in  FIG. 9 . 
     Referring to  FIGS. 3, 4, 5, 6, 7, 8, 9, 12, and 13 , a display device may include a lower wiring BML, a first active layer ACT 1 , a first conductive layer  110 , a second conductive layer  120 , a second active layer ACT 2 , a third conductive layer  130 , a fourth conductive layer  140 , a fifth conductive layer  150 , a first electrode  160 , an emission layer  170 , and a second electrode  180 , which are disposed on a substrate SUB. The display device described with reference to  FIGS. 3 to 9, 12, and 13  may be substantially the same as or similar to the display device described with reference to  FIGS. 3 to 11  except for the addition of the lower wiring BML. Accordingly, descriptions on components of the display device described with reference to  FIGS. 3 to 9, 12, and 13 , which are substantially the same as or similar to those of the display device described with reference to  FIGS. 3 to 11 , will not be repeated. 
     The lower wiring BML may be disposed between the substrate SUB and the buffer layer BUF. The lower wiring BML may include a conductive material such as molybdenum (Mo), copper (Cu), aluminum (Al), titanium (Ti) etc., or amorphous silicon. 
     The lower wiring BML may overlap the first conductive pattern  113 . The lower wiring BML may be disposed under the driving transistor T 1 . Specifically, the lower wiring BML may be disposed under a portion of the first active layer ACT 1  which overlaps the first conductive pattern  113 . 
     When an electric field due to polarization of the substrate SUB containing polyimide is formed between the driving transistor T 1  and the substrate SUB through under the driving transistor T 1 , the characteristics of the driving transistor T 1  may change, and thus, the brightness of light emitted from the light emitting element EL may change. When the lower wiring BML is disposed under the portion of the first active layer ACT 1  which overlaps the first conductive pattern  113 , the lower wiring BML may prevent an electric field from being formed between the first active layer ACT 1  and the substrate SUB through under the driving transistor T 1 . Accordingly, the characteristics of the driving transistor T 1  may not change, and the brightness of light emitted from the light emitting element EL may constantly maintain. 
     In an embodiment, the lower wiring BML may be connected to the gate electrode, the first electrode, or the second electrode of the driving transistor T 1 . In an embodiment, the lower wiring BML may receive the driving voltage ELVDD in  FIG. 2 , the first initialization voltage VINT in  FIG. 2 , or the second initialization voltage AINT in  FIG. 2 . 
     A barrier layer BAR may be disposed between the substrate SUB and the lower wiring BML. The barrier layer BAR may block diffusion of impurities such as oxygen, moisture, or the like through the substrate SUB to above the substrate SUB. Further, the barrier layer BAR may provide a planarized upper surface on the substrate SUB. The barrier layer BAR may include an inorganic insulation material such as silicon oxide, silicon nitride, silicon oxynitride, or the like. Alternatively, the barrier layer BAR may be omitted. 
       FIG. 14  is a plan view illustrating a first active layer ACT 1  of a display device according to an embodiment.  FIG. 15  is a plan view illustrating a first conductive layer  110  of a display device according to an embodiment.  FIG. 16  is a plan view illustrating a second conductive layer  120  of a display device according to an embodiment.  FIG. 17  is a plan view illustrating a second active layer ACT 2  of a display device according to an embodiment.  FIG. 18  is a plan view illustrating a third conductive layer  130  of a display device according to an embodiment.  FIG. 19  is a plan view illustrating a fourth conductive layer  140  of a display device according to an embodiment.  FIG. 20  is a plan view illustrating a fifth conductive layer  150  of a display device according to an embodiment. 
     Referring to  FIGS. 14, 15, 16, 17, 18, 19, and 20 , a display device may include a first active layer ACT 1 , a first conductive layer  110 , a second conductive layer  120 , a second active layer ACT 2 , a third conductive layer  130 , a fourth conductive layer  140 , a fifth conductive layer  150 , a first electrode, an emission layer, and a second electrode, which are disposed on a substrate SUB. Descriptions on components of the display device described with reference to  FIGS. 14 to 20 , which are substantially the same as or similar to those of the display device described with reference to  FIGS. 3 to 11 , will not be repeated. 
     The second conductive layer  120  may include a first compensation control line  121 , a first initialization control line  122 , and a second conductive pattern  123 . 
     The third conductive layer  130  may include a second compensation control line  131 , a second initialization control line  132 , a first initialization voltage line  133 , and a second gate connection electrode  134 . The first initialization voltage line  133  may be spaced apart from the second initialization control line  132 , and may extend in the first direction DR 1 . The second gate connection electrode  134  may overlap the first conductive pattern  113 . The second gate connection electrode  134  may be connected to the first conductive pattern  113  through a contact hole. 
     The fourth conductive layer  140  may include a second initialization voltage line  141 , a first gate connection electrode  142 , an active connection electrode  143 , a data connection electrode  144 , a driving voltage connection electrode  145 , a first light emitting element connection electrode  146 , and a first bridge line  148 . 
     The first gate connection electrode  142  may be connected to the second gate connection electrode  134  and the second active layer ACT 2  through contact holes, respectively. Accordingly, the first gate connection electrode  142  and the second gate connection electrode  134  may connect the gate electrode of the driving transistor T 1 , the second electrode of the compensation transistor T 3 , and the second electrode of the first initialization transistor T 4 . 
     The first bridge line  148  may be spaced apart from the first light emitting element connection electrode  146 . The first bridge line  148  may extend in the first direction DR 1 . 
     The fifth conductive layer  150  may include a data line  151 , a driving voltage line  152 , a second light emitting element connection electrode  153 , and a second bridge line  154 . The second bridge line  154  may be spaced apart from the second light emitting element connection electrode  153 . The second bridge line  154  may extend in the second direction DR 2 . 
     In an embodiment, the first bridge line  148  and the second bridge line  154  may serve to transmit the data voltage DATA to the data line  151 . For example, the first bridge line  148  and the second bridge line  154  may be connected to each other through a contact hole in a portion where the first bridge line  148  and the second bridge line  154  intersect, and the second bridge line  154  may be connected to a data driver generating the data voltage DATA. As the first bridge line  148  and the second bridge line  154  are additionally disposed, the number of data lines  151  connected to the data driver may decrease. Accordingly, a planar area of the data driver may decrease, and thus, a dead space of the display device may be reduced. 
       FIG. 21  is a layout view illustrating a display device according to an embodiment.  FIG. 22  is a cross-sectional view illustrating an example of the display device taken along a line II-IF in  FIG. 21 .  FIG. 23  is a cross-sectional view illustrating another example of the display device taken along the line II-II′ in  FIG. 21 . 
     Descriptions on components of the display device described with reference to FIGS.  21  to  23 , which are substantially the same as or similar to those of the display device described with reference to  FIGS. 10 and 11 , will not be repeated. 
     Referring to  FIGS. 21, 22, and 23 , the first compensation control line  121 ′ may be disposed on the same layer as the scan line  111 ′. In an embodiment, as illustrated in  FIG. 22 , the scan line  111 ′ and the first compensation control line  121 ′ may be disposed between the second insulation layer  102  and the third insulation layer  103 . In another embodiment, as illustrated in  FIG. 23 , the scan line  111 ′ and the first compensation control line  121 ′ may be disposed between the first insulation layer  101  and the second insulation layer  102 . 
     In the present embodiment, the first electrode of the boosting capacitor CBT and the first electrode of the compensation transistor capacitor T 3 C may be disposed on the same layer, and the second electrode of the boosting capacitor CBT and the second electrode of the compensation transistor capacitor T 3 C may be disposed on the same layer. Accordingly, the correlation between the planar area of the boosting capacitor CBT determined by the scan line  111 ′ and the second active layer ACT 2  and the planar area of the compensation transistor capacitor T 3 C determined by the first compensation control line  121 ′ and the second active layer ACT 2  may be relatively high, and thus, the deviation of the kickback voltage may decrease. 
     The display device according to the embodiments may be applied to a display device included in a computer, a notebook, a mobile phone, a smart phone, a smart pad, a PMP, a PDA, an MP3 player, or the like. 
     Although the display devices according to the embodiments have been described with reference to the drawings, the illustrated embodiments are examples, and may be modified and changed by a person having ordinary knowledge in the relevant technical field without departing from the scope and spirit described in the following claims.