Patent Publication Number: US-11037484-B2

Title: Display device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation application of U.S. patent application Ser. No. 15/476,213 filed on Mar. 31, 2017, which is a continuation application of U.S. patent application Ser. No. 14/274,541 filed on May 9, 2014 (now U.S. Pat. No. 9,627,415), which claims priority to and the benefit of Korean Patent Application No. 10-2014-0001803 filed in the Korean Intellectual Property Office (KIPO) on Jan. 7, 2014, the contents of the prior applications being herein incorporated by reference. 
    
    
     BACKGROUND 
     (a) Technical Field 
     The inventive concept relates to a display device, and more particularly, to a display device including a gate driver. 
     (b) Description of the Related Art 
     Generally, a display device includes a plurality of pixels which are portions displaying images, and drivers. The drivers include a data driver applying a data voltage to the pixel, and a gate driver applying a gate signal to the pixel. The gate driver and the data driver may be mounted on a printed circuit board (PCB) as an IC chip and the PCB is connected to a display panel. The IC chip may be directly mounted on the display panel. 
     However, recently, in the case of a gate driver without requiring high mobility of a thin film transistor channel, a structure in which the gate driver is not formed by a separate chip, but integrated on the display panel has been developed. 
     The gate driver includes a shift register having a plurality of stages which are serially connected to each other, and a plurality of signal transferring wirings transferring a clock signal and a driving control signal having a low voltage and the like to the shift register. 
     Each of the plurality of stages is connected to respective gate line. Each of the plurality of stages sequentially outputs a gate signal to each gate line in a predetermined order. 
     The signal transferring wirings generally extend in a direction in which the plurality of stages is arranged. 
     The above information disclosed in this Background section is only for enhancement of understanding of the background of the inventive concept and therefore it may contain information that does not form the prior art. 
     SUMMARY 
     According to a layout of the stages of the gate driver and the plurality of signal transferring wirings transferring various driving control signals to the stages, any one signal transferring wiring and another signal wiring or a signal line connected therewith may overlap with each other and cross each other. As such, at a portion where the signal transferring wirings transferring different signals cross each other, a parasitic capacitor is formed, and thus a load of the signal transferring wirings may be increased. As a result, power consumption of the gate driver may be increased, and heat generation may be increased. 
     The inventive concept has been made in an effort to provide a display device having advantages of preventing a parasitic capacitor from being generated by reducing overlap between signal transferring wirings transferring a driving control signal to a gate driver and reduce power consumption of the gate driver by reducing a load of the signal transferring wirings. Particularly, the inventive concept has been made in an effort to provide a display device having advantages of reducing a load of a clock signal wiring transferring a clock signal to the gate driver. 
     An exemplary embodiment of the inventive concept provides a display device, including: a plurality of pixels; a plurality of gate lines connected to the plurality of pixels; a gate driver including a plurality of stages outputting gate signals to the plurality of gate lines; a clock signal wiring transferring a clock signal to the gate driver; a voltage wiring transferring an off voltage to the gate driver, in which the clock signal wiring is positioned at a first side of the gate driver, and the voltage wiring is disposed on a second side facing the first side of the gate driver. 
     The plurality of stages may have spaces between the plurality of stages. The clock signal wiring may have a main clock signal line extending in a first direction and a sub clock signal line extending in a second direction substantially perpendicular to the first direction. The voltage wiring may have a main voltage line extending in a first direction and a sub voltage line extending in a second direction. The sub clock signal line and the sub voltage line may be disposed on the different space. 
     The voltage wiring may include a first voltage wiring and a second voltage wiring which transfer different voltages to the gate driver, the first voltage wiring including a first main voltage line extending in the first direction and a first sub voltage line extending in the second direction, the second voltage wiring including a second main voltage line extending in a first direction and a second sub voltage line extending in a second direction. 
     The first main voltage line, the second main voltage line and the first sub voltage line may be formed of a same material in a same plane, and the second sub voltage line may be formed of a different material from the first main voltage line, the second main voltage line and the first sub voltage line. 
     The second sub voltage line is connected to the second main voltage line via a contact assistance connecting the second main voltage line and the second sub voltage line via a first contact hole and a second contact hole that expose the second main voltage line and the second sub voltage line, respectively. 
     The voltage wiring may be disposed between the gate driver and the plurality of pixels in a plan view. 
     The plurality of gate lines may cross the first main voltage line and the second main voltage line. 
     According to the exemplary embodiment of the inventive concept, it is possible to prevent a parasitic capacitor from being generated by reducing overlapping between signal transferring wirings transferring a driving control signal to a gate driver and reduce a load of the signal transferring wirings. As a result, it is possible to reduce power consumption of the gate driver and reduce heat generation. 
     Particularly, it is possible to reduce power consumption of the gate driver by reducing a load of a clock signal wiring transferring a clock signal to the gate driver. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of a display device according to an exemplary embodiment of the inventive concept. 
         FIG. 2  is a schematic circuit diagram of one pixel of the display device according to the exemplary embodiment of the inventive concept. 
         FIG. 3  is a block diagram of a display device according to an exemplary embodiment of the inventive concept. 
         FIG. 4  is a block diagram of a gate driver according to the exemplary embodiment of the inventive concept. 
         FIG. 5  is an example of a circuit diagram of one stage of the gate driver according to the exemplary embodiment of the inventive concept. 
         FIG. 6  is a layout view of a gate driver and a signal transferring wiring according to the exemplary embodiment of the inventive concept. 
         FIG. 7  is a cross-sectional view illustrating the gate driver and the signal transferring wiring illustrated in  FIG. 6  taken along line VII-VII. 
         FIG. 8  is a diagram enlarging a part of the gate driver and the signal transferring wiring illustrated in  FIG. 6 . 
         FIG. 9  is a cross-sectional view illustrating the gate driver and the signal transferring wiring illustrated in  FIG. 8  taken along line IX-IX. 
         FIG. 10  is another cross-sectional view illustrating the gate driver and the signal transferring wiring illustrated in  FIG. 8  taken along line IX-IX. 
         FIG. 11  is a cross-sectional view of the gate driver and the signal transferring wiring illustrated in  FIG. 8  taken along line XI-XI. 
         FIG. 12  is a cross-sectional view of the gate driver and the signal transferring wiring illustrated in  FIG. 8  taken along line XII-XII. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The inventive concept will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the inventive concept are shown. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the inventive concept. 
     In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like reference numerals designate like elements throughout the specification. It will be understood that when an element such as a layer, film, region, or substrate is referred to as being “on” another element, it can be formed directly on the other element or formed with intervening elements. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. 
     Throughout this specification and the claims that follow, when it is described that an element is “coupled” to another element, the element may be “directly coupled” to the other element or “electrically coupled” to the other element through a third element. In addition, unless explicitly described to the contrary, the word “comprise” and variations such as “comprises” or “comprising” will be understood to imply the inclusion of stated elements but not the exclusion of any other elements. 
     First, a display device according to an exemplary embodiment of the inventive concept will be described with reference to  FIGS. 1 to 3 . 
       FIG. 1  is a block diagram of a display device according to an exemplary embodiment of the inventive concept,  FIG. 2  is a schematic circuit diagram of one pixel of the display device according to the exemplary embodiment of the inventive concept, and  FIG. 3  is a block diagram of a display device according to an exemplary embodiment of the inventive concept. 
     Referring to  FIG. 1 , a display device according to an exemplary embodiment of the inventive concept includes a display panel  300 , a gate driver  400 , a data driver  500 , and a signal controller  600 . 
     The display panel  300  may be display panels included in various display devices such as a liquid crystal display (LCD), an organic light emitting display (OLED), and an electrowetting display (EWD). 
     The display panel  300  includes a display area DA displaying an image, and a peripheral area PA surrounding the display area DA. 
     In the display area DA, a plurality of gate lines G 1 -Gn, a plurality of data lines D 1 -Dm, and a plurality of pixels PX connected to the plurality of gate lines G 1 -Gn and the plurality of data lines D 1 -Dm are disposed. 
     The gate lines G 1 -Gn may transfer gate signals, extend substantially in a row direction, and be substantially parallel to each other. 
     The data lines D 1 -Dm may transfer data voltages corresponding to the image signals, extend substantially in a column direction, and be substantially parallel to each other. 
     The plurality of pixels PX may be arranged substantially in a matrix form. 
     Referring to  FIG. 2 , each pixel PX may include at least one switching element SW connected to a gate line Gi and a data line Dj, and at least one pixel electrode  191  connected to the gate line Gi and the data line Dj. The switching element SW may be a three-terminal element such as a thin film transistor integrated on the display panel  300 . The thin film transistor includes a gate terminal, an input terminal, and an output terminal. The switching element SW may be turned on or off according to a gate signal of the gate line Gi to selectively transfer a data signal from the data line Dj to the pixel electrode  191 . The switching element SW may include at least one thin film transistor. The pixel PX may display a corresponding image according to the data voltage applied to the pixel electrode  191 . 
     The peripheral area PA may be covered by the light blocking member. The peripheral area PA may surround the display area DA or be positioned at an edge of the display panel  300 . 
     In the peripheral area PA, the gate driver  400  and a plurality of signal transferring wirings (not illustrated) transferring driving control signals to the gate driver  400  may be positioned. In the peripheral area PA, the gate lines G 1 -Gn and the data lines D 1 -Dm of the display area DA may be extended. 
     The signal controller  600  controls the drivers such as the data driver  500  and the gate driver  400 . 
     The signal controller  600  receives input image signals and an input control signal controlling the display of the input image signals from an external graphic controller (not illustrated). An example of the input control signal includes a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a main clock MCLK, a data enable signal DE, and the like. The signal controller  600  convert the input image signal to a digital image signal DAT using the input image signal and the input control signal, and generates a gate control signal CONT 1 , a data control signal CONT 2 , and the like. The gate control signal CONT 1  includes a scanning start signal STV instructing scanning start, at least one clock signal controlling an output period of a gate-on voltage Von, at least one off voltage, and the like. The data control signal CONT 2  includes a horizontal synchronization start signal informing transmission start of the digital image signal DAT for pixels PX in one row, a load signal, a data clock signal, and the like. 
     The signal controller  600  may be mounted on a printed circuit board (PCB), and may transfer the data control signal CONT 2 , the gate control signal CONT 1 , the digital image signal DAT, and the like to the gate driver  400  and the data driver  500  through a film (not illustrated) such as a flexible printed circuit film. 
     The data driver  500  is connected to the data lines D 1 -Dm of the display panel  300 . The data driver  500  receives the data control signal CONT 2  and the digital image signal DAT from the signal controller  600  and selects a gray voltage corresponding to each digital image signal DAT to convert the digital image signal DAT into an analog data signal, and then apply the converted analog data signal to the corresponding data lines D 1 -Dm. 
     The data driver  500  may be mounted on the peripheral area PA of the display panel  300  as a plurality of driving IC chips, or mounted on a flexible printed circuit film or a printed circuit board (PCB) connected to the display panel  300 . According to another exemplary embodiment of the inventive concept, the data driver  500  may be integrated in the peripheral area PA of the display panel  300  by the same process together with an electric element such as a thin film transistor of the display area DA. 
     The gate driver  400  is connected to the gate lines G 1 -Gn. The gate driver  400  generates a gate signal having a gate-on voltage Von and a gate-off voltage Voff according to the gate control signal CONT 1  from the signal controller  600 , and applies the gate signals to the gate lines G 1 -Gn. The gate-on voltage Von is a voltage which is applied to the gate terminal of the thin film transistor in the display area DA to turn on the thin film transistor, and the gate-off voltage Voff is a voltage which is applied to the gate terminal of the thin film transistor to turn off the thin film transistor. 
     Referring to  FIG. 1 , the gate driver  400  according to the exemplary embodiment of the inventive concept includes a plurality of stages ST 1 -STn which are serially connected to each other and arranged in sequence. The output of each stage is connected to a data input of the next stage in a chain. 
     The plurality of stages ST 1 -STn generates gate signals to sequentially transfer the gate signals to the respective gate lines G 1 -Gn. Each of the stages ST 1 -STn includes a gate driving circuit connected to each of the gate lines G 1 -Gn, and may have a gate output terminal (not illustrated) outputting a gate signal. 
     The stages ST 1 -STn of the gate driver  400  may be positioned in the peripheral area PA at the left or the right of the display area DA, and arranged in a column direction in a line. In  FIG. 1 , an example in which the plurality of stages ST 1 -STn is positioned in the peripheral area PA positioned at the left of the display area DA is illustrated, but the positions of the plurality of stages ST 1 -STn are not limited thereto, and the plurality of stages ST 1 -STn may be positioned at least one position of the peripheral areas PA at the right, the upper side, or the lower side of the display area DA. 
     According to an exemplary embodiment of the inventive concept, each of the stages ST 1 -STn may be connected to output terminals of previous stages ST 1 -STn or subsequent stages ST 1 -STn. A first stage ST 1  without having the previous stage may receive a scanning start signal STV notifying a start of one frame. The last stage STn without having the subsequent stage may not be connected to the output terminal of the subsequent stage, but receive another signal, for example, a reset signal or another scanning start signal. 
     Each of the stages ST 1 -STn may include an active element such as a plurality of thin film transistors and a passive element such as a capacitor which are integrated in the peripheral area PA of the display panel  300 . The active element and the passive element included in the gate driver  400  may be manufactured by the same process as the thin film transistor and the like included in the pixel PX of the display area DA. 
     The driving control signals such as the off voltage and the clock signal required for driving the plurality of gate drivers  400  including the gate control signal CONT 1  may be input to the gate driver  400  through the plurality of signal transferring wirings formed at a portion adjacent to the gate driver  400 . The plurality of signal transferring wirings may be positioned in the peripheral area PA of the display panel  300  where the gate driver  400  is positioned and extended in a column direction. 
     Referring to  FIG. 3 , the display device according to the exemplary embodiment of the inventive concept is almost the same as the display device illustrated in  FIGS. 1 and 2  described above, but the gate driver  400  may include a first gate driver  400   a  and a second gate driver  400   b  which are positioned in left and right peripheral areas PA of the display device  300 , respectively. 
     Although not illustrated, the first gate driver  400   a  and the second gate driver  400   b  may receive driving control signals such as the gate control signal CONT 1  through different signal transferring wirings. 
     Each of the first gate driver  400   a  and the second gate driver  400   b  may have substantially the same structure and feature as the gate driver  400  illustrated in  FIG. 1  described above. 
     Each of the first gate driver  400   a  and the second gate driver  400   b  includes the plurality of stages ST 1 -STn arranged in a column direction in a line. The corresponding stages of the first gate driver  400   a  and the second gate driver  400   b  may be connected to the same gate line G 1 -Gn to apply a gate signal as illustrated in  FIG. 3 . 
     According to another exemplary embodiment of the inventive concept, the first gate driver  400   a  and the second gate driver  400   b  may be connected to the different gate lines G 1 -Gn to apply the gate signal. For example, the first gate driver  400   a  may be connected to odd numbered gate lines G 1 , G 3  . . . and the second gate driver  400   b  may be connected to even numbered gate lines G 2 , G 4 , . . . . On the contrary, the first gate driver  400   a  may be connected to even numbered gate lines G 2 , G 4 , . . . and the second gate driver  400   b  may be connected to odd numbered gate G 1 , G 3 , . . . , lines. 
     Next, a detailed structure of the gate driver according to the exemplary embodiment of the inventive concept will be described with reference to  FIG. 4 . 
       FIG. 4  is a block diagram of a gate driver according to the exemplary embodiment of the inventive concept. 
     Referring to  FIGS. 1, 3, and 4 , the gate drivers  400 ,  400   a , and  400   b  according to the exemplary embodiment of the inventive concept include a plurality of stages ST 1 , . . . , STi, ST(i+1), ST(i+2), . . . which is serially connected to each other and sequentially outputs gate signals Gout 1, . . . , Gout(i), Gout i+1, Gout i+2, . . . , Gout(n), and a plurality of signal transferring wirings transferring various driving control signals CLK, CLKB, VSS 1 , VSS 2 , and STV inputted to the stages ST 1 , . . . , STi, ST(i+1), ST (i+2), . . . . Here, the signal transferring wirings will be named according to the driving control signals CLK, CLKB, VSS 1 , and VSS 2  transferred by the signal transferring wiring, respectively. 
     The plurality of signal transferring wirings may include, for example, clock signal wirings transferring a clock signals including a clock signal CLK and a clock signal bar CLKB, a voltage wiring including first and second voltage wirings VSS 1  and VSS 2  transferring the first off voltage VSS 1  (firs off voltage) and the second off voltage VSS 2  (second off voltage), a scanning start signal wiring (not illustrated) transferring the scanning start signal STV, and the like. Phases of the clock signal CLK and the clock signal bar CLKB may be opposite to each other. 
     According to the exemplary embodiment of the inventive concept, the plurality of signal transferring wirings is separated into a first signal transferring wiring disposed on the first signal transferring wiring region SL 1  and a second signal transferring wiring disposed on the second signal transferring wiring region SL 2 . The first signal transferring wiring region SL 1  and the second signal transferring wiring region SL 2  are positioned at both sides of the plurality of stages ST 1 , . . . , STi, ST(i+1), ST(i+2), . . . arranged in a column direction. For example, the clock signal wirings transferring the clock signals CLK and CLKB may be positioned in the first signal transferring wiring region SL 1 , and the first and second voltage wirings VSS 1  and VSS 2  may be positioned in the second signal transferring wiring region SL 2 . 
     Particularly, according to the exemplary embodiment of the inventive concept, the first and second voltage wirings VSS 1  and VSS 2  are positioned in the signal transferring wiring region SL 2  which are opposite to the signal transferring wiring region SL 1  in which the clock signal wirings transferring the clock signals CLK and CLKB are positioned. Thus the first and second voltage wiring VSS 1  and VSS 2  do not to cross or overlap with the clock signal wirings transferring the clock signals CLK and CLKB. 
     Each of the stages ST 1 , . . . , STi, ST(i+1), ST(i+2), . . . may include a clock terminal CK, a first off voltage input terminal VS 1 , a second off voltage input terminal VS 2 , a first output terminal OUT 1 , a second output terminal OUT 2 , a first input terminal IN 1 , a second input terminal IN 2 , and a third input terminal IN 3 . 
     One of the clock signal CLK and the clock signal bar CLKB may be input to the clock terminal CK of each of the stages ST 1 , . . . , STi, ST(i+1), ST(i+2), . . . . For example, the clock signals CLK may be applied to the clock terminals CK of the odd numbered stages ST 1 , ST 3  . . . , and the clock signals bar CLKB may be applied to the clock terminals CK of the even numbered stages ST 2 , ST 4  . . . . On the contrary, the clock signals CLK may be applied to the clock terminals CK of the even numbered stages ST 2 , ST 4  . . . , and the clock signals bar CLKB may be applied to the clock terminals CK of the odd numbered stages ST 1 , ST 3  . . . . 
     The first off voltage VSS 1  and the second off voltage VSS 2  which are off voltages having different voltage levels are input to the first off voltage input terminal VS 1  and the second off voltage input terminal VS 2 , respectively. According to an exemplary embodiment of the inventive concept, the second off voltage VSS 2  may be lower than the first off voltage VSS 1 . Values of the first off voltage VSS 1  and the second off voltage VSS 2  may vary according to the pixel used, and be approximately −5 V or less. The first off voltage VSS 1  may be, for example, approximately −5.6 V, and the second off voltage VSS 2  may be, for example, approximately −9.2 V. 
     The first output terminal OUT 1  is a gate output terminal outputting the gate signals Gout 1 , . . . , Gout(i), Gout(i+1), Gout(i+2), . . . generated by the stages ST 1 , . . . , STi, ST(i+1), ST(i+2), . . . , respectively. The second output terminal OUT 2  is a carry output terminal outputting carry signals Cr 1 , . . . , Cr(i), Cr(i+1), Cr(i+2), . . . generated by the stages ST 1 , . . . , STi, ST(i+1), ST(i+2), . . . , respectively. 
     The first input terminal IN 1  may receive carry signals Cr 1 , . . . , Cr(i), Cr(i+1), Cr(i+2), . . . of the previous stage. In the case of the first stage ST 1  which has no previous stage, the scanning start signal STV may be input to the first input terminal IN 1 . 
     The carry signals Cr 1 , . . . , Cr(i), Cr(i+1), Cr(i+2), . . . of the subsequent stage, particularly, the carry signals Cr 1 , . . . , Cr(i), Cr(i+1), Cr(i+2), . . . of the next stage may be input to the second input terminal IN 2 . 
     The carry signals Cr 1 , . . . , Cr(i), Cr(i+1), Cr(i+2), . . . of the subsequent stage, particularly, the carry signals Cr 1 , . . . , Cr(i), Cr(i+1), Cr(i+2), . . . of the stages after next stages may be input to the third input terminal IN 3 . 
     Next, a detailed structure of each stage of the gate driver illustrated in  FIG. 4  described above will be described with reference to  FIG. 5 . 
       FIG. 5  illustrates an example of the circuit diagram of one stage, for example, an i-th stage STi of the gate driver according to the exemplary embodiment of the inventive concept. 
     The stage STi according to the exemplary embodiment of the inventive concept includes a plurality of transistors Tr 1 , Tr 2 , Tr 4 , Tr 6 , Tr 7 , Tr 8 , Tr 9 , Tr 10 , Tr 11 , Tr 12 , Tr 13 , and Tr 15  and at least one capacitor C 1  in addition to the clock terminal CK, the first off voltage input terminal VS 1 , the second off voltage input terminal VS 2 , the first output terminal OUT 1 , the second output terminal OUT 2 , the first input terminal IN 1 , the second input terminal IN 2 , and the third input terminal IN 3 , as described above.  FIG. 5  illustrates 12 transistors, but the number of transistors is not limited thereto. 
     The plurality of transistors and capacitor included in the stage STi may be classified into a buffer portion  411 , a pull-up portion  413 , a carry portion  414 , a discharge portion  415 , a pull-down portion  416 , a switching portion  417 , a first storage portion  418 , and a second storage portion  419 , according to a function. 
     The buffer portion  411  transfers a carry signal of the previous stages or a scanning start signal STV to the pull-up portion  413 . The buffer portion  411  may receive, for example, a carry signal Cr(i−1) of the previous stage ST(i−1). In the exemplary embodiment, it is described that the buffer portion  411  transfers the carry signal Cr(i−1) of the previous stage ST(i−1), but is not limited thereto. 
     The buffer portion  411  may include a fourth transistor Tr 4 . An input terminal and a control terminal of the fourth transistor Tr 4  are connected to the first input terminal IN 1 , and an output terminal is connected to a node Q. Thus, the fourth transistor Tr 4  may act like a diode with characteristics similar to a pn-junction diode. When the carry signal Cr(i−1) input to the first input terminal IN 1  is at a high level, the fourth transistor Tr 4  becomes forward bias and a large current flows through the fourth transistor Tr 4 . As a result, the output voltage becomes a high level voltage. On the contrary, when the carry signal Cr(i−1) is at a low level, the fourth transistor Tr 4  becomes reverse biased and no current flows through the fourth transistor Tr 4 . 
     The pull-up portion  413  is connected to the clock terminal CK, the node Q, and the first output terminal OUT 1 , and outputs a gate signal Gout(i) through the first output terminal OUT 1 . 
     The pull-up portion  413  may include, for example, a first transistor Tr 1  and a capacitor C 1 . The control terminal of the first transistor Tr 1  is connected to the node Q, the input terminal is connected to the clock terminal CK, and the output terminal is connected to the first output terminal OUT 1 . The capacitor C 1  is connected between the control terminal and the output terminal of the first transistor Tr 1 . The capacitor C 1  is charged in response to the carry signal Cr(i−1) provided by the buffer portion  411 . When the clock signals CLK and CLKB from the clock terminal CK are at the high voltages while the voltage of the node Q is at the high level according to the charge of the capacitor C 1 , the first transistor Tr 1  is bootstrapped. In this case, the node Q is boosted from the charging voltage of the capacitor C 1  to a boosting voltage. When the boosting voltage is applied to the control terminal of the first transistor Tr 1 , the first transistor Tr 1  outputs the high voltages of the clock signals CLK and CLKB as a gate-on voltage Von through the first output terminal OUT 1 . When the voltage of the node Q drops to the low level, the first transistor Tr 1  is turned off, and the off voltage may be output to the first output terminal OUT 1 . 
     The pull-down portion  416  pulls-down the voltage of the gate signal Gout(i) output to the first output terminal OUT 1  to the first off voltage VSS 1  applied to the first off voltage input terminal VS 1  when the carry signal of one of the subsequent stages Cr(i+1) is supplied from the second input terminal IN 2 . For example, a carry signal Cr(i+1) of the next stage ST(i+1) may be received in the second input terminal IN 2 . In the exemplary embodiment, it is described that the pull-down portion  416  receives the carry signal Cr(i+1) of the next stage ST(i+1), but is not limited thereto. 
     The pull-down portion  416  may include a second transistor Tr 2 . A control terminal of the second transistor Tr 2  is connected to the second input terminal IN 2 , an input terminal is connected to the first off voltage input terminal VS 1 , and an output terminal is connected to the first output terminal OUT 1 . 
     The carry portion  414  is connected to the clock terminal CK, the node Q, and the second output terminal OUT 2 , and outputs a carry signal Cr(i) through the second output terminal OUT 2 . The carry portion  414  outputs the high voltage of the clock signals CLK and CLKB received in the clock terminal CK as the carry signal Cr(i) when the high voltage is applied to the node Q. 
     The carry portion  414  may include a fifteenth transistor Tr 15 . The clock terminal CK is connected to an input terminal of the fifteenth transistor Tr 15 , a control terminal is connected to the node Q, and an output terminal is connected to the second output terminal OUT 2 . 
     The first storage portion  418  maintains the output of the second output terminal OUT 2  at the second off voltage VSS 2  in response to the signal of the node N except when the second output terminal outputs the high voltage of the carry signal Cr(i). 
     The first storage portion  418  may include an eleventh transistor Tr 11 . A control terminal of the eleventh transistor Tr 11  is connected to the node N, an input terminal is connected to the second off voltage input terminal VS 2 , and an output terminal is connected to the second output terminal OUT 2 . The eleventh transistor Tr 11  maintain the voltage of the carry signal Cr(i) at the second off voltage VSS 2  when the voltage of the node N is at a high level. 
     The switching portion  417  applies a signal having the same phase as the clock signals CLK and CLKB received in the clock terminal CK to the node N for a period other than the output period of the high voltage of the carry signal Cr(i). The switching portion  417  may include a twelfth transistor Tr 12 , a seventh transistor Tr 7 , and a thirteenth transistor Tr 13 , and an eighth transistor Tr 8 . 
     The discharge portion  415  discharges the high voltage of the node Q to the second off voltage VSS 2  having a lower level than the first off voltage VSS 1  in response to the carry signal of at least one of the subsequent stages. 
     The discharge portion  415  may include a first discharge portion  415 _ 1  including a ninth transistor Tr 9 , and a second discharge portion  415 _ 2  including a sixth transistor Tr 6 . 
     The first discharge portion  415 _ 1  discharges the voltage of the node Q to the first off voltage VSS 1  applied to the first off voltage input terminal VS 1  when the carry signal Cr(i+1) is received from the second input terminal IN 2 . 
     The second discharge portion  415 _ 2  discharges the voltage of the node Q to the second off voltage VSS 2  applied to the second off voltage input terminal VS 2  when the carry signal is applied to the third input terminal IN 3 . For example, the carry signal Cr(i+2) of the stage ST(i+2) the stage after next stage may be received in the third input terminal IN 3 . 
     The second storage portion  419  maintains the voltage of the node Q at the second off voltage VSS 2  in response to the signal of the node N for the remaining period of the frame. The second storage portion  419  may include a tenth transistor Tr 10 . 
     The structure of one stage STi of the gate driver  400  illustrated in  FIG. 5  is an example, but is not limited thereto. 
     Next, a structure of a gate driver and signal transferring wirings of a display device according to an exemplary embodiment of the inventive concept will be described with reference to  FIGS. 6 to 12  together with the drawings described above. 
       FIG. 6  is a layout view of a gate driver and signal transferring wirings according to an exemplary embodiment of the inventive concept,  FIG. 7  is a cross-sectional view illustrating the gate driver and the signal transferring wiring illustrated in  FIG. 6  taken along line VII-VII,  FIG. 8  is a diagram enlarging a part of the gate driver and the signal transferring wiring illustrated in  FIG. 6 ,  FIG. 9  is a cross-sectional view illustrating the gate driver and the signal transferring wiring illustrated in  FIG. 8  taken along line IX-IX,  FIG. 10  is another cross-sectional view illustrating the gate driver and the signal transferring wiring illustrated in  FIG. 8  taken along line IX-IX,  FIG. 11  is a cross-sectional view of the gate driver and the signal transferring wiring illustrated in  FIG. 8  taken along line XI-XI, and  FIG. 12  is a cross-sectional view of the gate driver and the signal transferring wiring illustrated in  FIG. 8  taken along line XII-XII. 
     First, referring to  FIG. 6 , a plurality of stages ST 1 , ST 2 , . . . included in the gate drivers  400 ,  400   a , and  400   b  is sequentially arranged in a column direction. A gate output terminal of each of the stages ST 1 , ST 2 , . . . is connected to the gate lines G 1 , G 2 , . . . of the display area DA to output a gate signal. 
     A clock signal wiring transferring the clock signals CLK and CLKB is positioned at one side of the plurality of stages ST 1 , ST 2  . . . . The clock signal wiring includes a main clock signal line  481  substantially extending in a column direction and a sub clock signal line  482  connected thereto. 
     The sub clock signal line  482  may include a portion extending substantially in a direction different from the main clock signal line  481 , and for example, may include a portion extending substantially in a row direction. An end portion of the sub clock signal line  482  has an extension  483 . 
     The main clock signal line  481  may include a plurality of signal lines extending in parallel with each other. 
     Each of the stages ST 1 , ST 2 , . . . may receive the clock signals CLK and CLKB from the main clock signal line  481  through the sub clock signal line  482 . Referring to  FIG. 6 , each sub clock signal line  482  extends between the adjacent stages ST 1 , ST 2 , . . . to be connected to the clock terminal CK of each of the stages ST 1 , ST 2 , . . . . 
     Referring to  FIG. 7 , the main clock signal line  481  and the sub clock signal line  482  may be formed of different layers. For example, the main clock signal line  481  may be formed of a gate conductive layer and be disposed on the substrate  110 . A gate insulating layer  140  may be disposed on the main clock signal line  481 . The sub clock signal line  482  may be formed of a data conductive layer and be disposed on the gate insulating layer  140 . 
     Here, the gate conductive layer includes a gate terminal of the thin film transistor included in the display area DA of the display panel  300  or the stages ST 1 , ST 2 , . . . of the gate driver  400  and gate lines G 1 , G 2 , . . . , and the like, and the data conductive layer may include an input terminal or an output terminal of the thin film transistor and data lines D 1 , D 2 , . . . . 
     The passivation layer  180  is disposed on the data conductive layer. The passivation layer  180  has contact holes exposing the main clock signal line  481  and the sub clock signal line  482 , respectively. 
     A contact assistant  88  connecting the main clock signal line  481  and the sub clock signal line is disposed on the passivation layer  180 . 
     The main clock signal line  481  and the sub clock signal line  482  may be electrically connected to each other by various methods. When the main clock signal line  481  and the sub clock signal line  482  are positioned at different layers from each other, the main clock signal line  481  and the sub clock signal line  482  may be electrically connected to each other through a contact assistant  88 . Referring to  FIG. 7 , the contact assistant  88  may be positioned, for example, on a passivation layer  180 . In this case, the gate insulating layer  140  and/or the passivation layer  180  may have a contact hole  188  exposing each of the main clock signal line  481  and an extension  483  of the sub clock signal line  482 . The contact assistant  88  may electrically and physically contact the main clock signal line  481  and the extension  483  of the sub clock signal line  482  through the contact hole  188 . 
     Referring back to  FIG. 6 , the first voltage wiring transferring the first off voltage VSS 1  and the second voltage wiring transferring the second off voltage VSS 2  are positioned at the other side of the plurality of stages ST 1 , ST 2 , . . . . That is, the plurality of stages ST 1 , ST 2 , . . . are disposed between the voltage wirings and the clock signal wirings. The first voltage wiring includes a main voltage line  471   a  extending substantially in a column direction and a sub voltage line  472   a  connected thereto. The second voltage wiring includes a main voltage line  471   b  extending substantially in a column direction and a sub voltage line  472   b  connected thereto. 
     The main voltage lines  471   a  and  471   b  may cross the gate lines G 1 , G 2  . . . extending in a column direction. 
     The main voltage line  471   a  and the main voltage line  471   b  are disposed on the same side of the plurality of stages ST 1 , ST 2 , . . . and extend in parallel with each other. 
     According to the exemplary embodiment of the inventive concept, the main voltage line  471   a  and the main voltage line  471   b  may be positioned between the plurality of stages ST 1 , ST 2 , . . . and the display area DA. That is, the main voltage line  471   a  and the main voltage line  471   b  may be positioned at the gate output terminal side of the stages ST 1 , ST 2 , . . . . Particularly, the main voltage line  471   a  of the first voltage wiring transferring the first off voltage VSS 1  may be positioned at the gate output terminal side of the stages ST 1 , ST 2 , . . . in order to optimize the layout, and the second voltage wiring is also positioned at the same side as the first voltage wiring of the stages ST 1 , ST 2 , . . . . 
     Accordingly, the first voltage wiring or the second voltage wiring is disposed on the opposite side of the clock signal wiring transferring the clock signals CLK and CLKB with respect to the stages ST 1 , ST 2 . Thus, the first voltage wiring or the second voltage wiring do not to cross or overlap another signal transferring wiring such as a clock signal wiring. Accordingly, the parasitic capacitor is not generated between the first voltage wiring or the second voltage wiring and other signal transferring wirings such as the clock signal wiring. Thus, a load of signal transferring wirings such as the clock signal wiring is decreased, thereby reducing power consumption and heat generation of the gate driver. 
     The sub voltage lines  472   a  and  472   b  may include a portion extending in a direction different from the main voltage lines  471   a  and  471   b , and for example, may include a portion extending in a row direction. 
     Each of the stages ST 1 , ST 2 , . . . may receive the first off voltage VSS 1  and the second off voltage VSS 2  from the main voltage lines  471   a  and  471   b  through the sub voltage lines  472   a  and  472   b . Referring to  FIG. 6 , each of the sub voltage lines  472   a  and  472   b  extends between the adjacent stages ST 1 , ST 2 , . . . to be connected to each of the first off voltage input terminal VS 1  and second off voltage input terminal VS 2  of each of the stages ST 1 , ST 2 , . . . . 
     The main voltage line  471   a  and the main voltage line  471   b  may be formed of the same layer. For example, both the main voltage line  471   a  and the main voltage line  471   b  may be formed of the data conductive layer. 
     The main voltage line  471   a  and the sub voltage line  472   a  of the first voltage wiring may be formed of different layers from each other, and the main voltage line  471   b  and the sub voltage line  472   b  of the second voltage wiring may be formed of the same layer and which is connected to each other. Accordingly, the sub voltage line  472   a  of the first voltage wiring and the sub voltage line  472   b  of the second voltage wiring may be positioned at different layers from each other, and may overlap with each other and extend in parallel as illustrated in  FIG. 7 . 
     Next, a structure of the first and second voltage wirings and the stages of the gate driver of the display device according to the exemplary embodiment of the inventive concept will be described in detail with reference to  FIGS. 8 to 12  in addition to  FIGS. 6 and 7 . 
     Referring to  FIGS. 8 to 12 , a gate conductive layer including a plurality of gate lines  121 , a plurality of sub voltage lines  472   a  of the first voltage wiring, and a gate terminal of a plurality of thin film transistors positioned in the display area DA or the plurality of thin film transistors included in the stages ST 1 , ST 2 , . . . is positioned on the substrate  110  including an insulating material such as glass and plastic. 
     Referring to  FIG. 7 , one end portion of the gate line  121  has an extension  127  to be connected to an output terminal of the first transistor Tr 1 . 
     The gate conductive layer may include the main clock signal line  481  of the clock signal wiring as described above. 
     The sub voltage line  472   a  of the first voltage wiring has an extension  477   a  to be connected to the main voltage line  471   a . The main voltage line  471   a  facing the extension  477   a  of the sub voltage line  472   a  may form a concave shape by decreasing a width of the wiring. 
     The other end portion of the sub voltage line  472   a  of the first voltage wiring has an extension  478   a  to be connected to each of an input terminal  173  of the stages ST 1 , ST 2  . . . . 
     The gate conductive layer may include at least one conductive material such as a metal. 
     A gate insulating layer  140  including an insulating material such as silicon nitride (SiNx) or silicon oxide (SiOx) is disposed on the gate conductive layer. 
     A data conductive layer including a plurality of data lines (not illustrated), the main voltage line  471   a  of the first voltage wiring, the main voltage line  471   b  and the sub voltage line  472   b  of the second voltage wiring, and an input terminal or an output terminal of the plurality of thin film transistors positioned in the display area DA or the plurality of thin film transistors included in the stages ST 1 , ST 2 , . . . is positioned on the gate insulating layer  140 . For example, the data conductive layer may include an output terminal  175  of the first transistor Tr 1  forming a gate output terminal of the stages ST 1 , ST 2 , . . . , and the input terminal  173  of the second transistor Tr 2  forming the first off voltage input terminal VS 1 . 
     The sub voltage line  472   a  of the first voltage wiring and the sub voltage line  472   b  of the second voltage wiring may be formed of different layers from each other, and may extend to overlap with each other as illustrated in  FIG. 8 . The sub voltage line  472   a  of the first voltage wiring and the sub voltage line  472   b  of the second voltage wiring extend between the adjacent stages ST 1 , ST 2 , . . . to be connected to each of the stages ST 1 , ST 2 , . . . . 
     The data conductive layer may include the sub clock signal line  482  of the clock signal wiring as described above. 
     The data conductive layer may include at least one conductive material such as a metal. 
     Referring to  FIGS. 8 to 12 , semiconductors  151   a  and  151   b  may be further positioned between the data conductive layer and the gate insulating layer  140 . The semiconductor  151   a  and  151   b  may include amorphous silicon, polysilicon, or an oxide semiconductor. The ohmic contacts  161   a  and  161   b , which may be made of a material such as n+ hydrogenated amorphous silicon in which an n-type impurity such as phosphorus is doped at a high concentration or silicide, may be further disposed between the semiconductor  151   a  and  151   b  and the data conductive layer. 
     A passivation layer  180  including an organic insulating material or an inorganic insulating material is disposed on the data conductive layer. 
     The gate insulating layer  140  and/or the passivation layer  180  includes a contact hole  187  exposing each of the main voltage line  471   a  of the first voltage wiring and the extension  477   a  of the sub voltage line  472   a , and a contact hole  186  exposing each of the extension  478   a  of the sub voltage line  472   a  of the first voltage wiring and the input terminal  173  of the second transistor Tr 2  adjacent thereto. Further, the gate insulating layer  140  and/or the passivation layer  180  may include a contact hole  182  exposing each of an extension  127  of the gate line  121  and the output terminal  175  of the first transistor Tr 1 . 
     A pixel electrode layer including a plurality of contact assistants  87 ,  86 , and  82  is positioned on the passivation layer  180 . The pixel electrode layer may include a plurality of pixel electrodes (not illustrated) of the display area DA. 
     The contact assistant  87  electrically connects the main voltage line  471  of the first voltage wiring and the extension  477   a  of the sub voltage line  472   a  with each other through the contact hole  187 . The contact assistant  86  electrically connects the extension  478   a  of the sub voltage line  472   a  of the first voltage wiring and the input terminal  173  of the second transistor Tr 2  of the stages ST 1 , ST 2 , . . . with each other through the contact hole  186 . The contact assistant  82  electrically connects the extension  127  of the gate line  121  and the output terminal  175  of the first transistor Tr 1  with each other through the contact hole  182 . 
     The pixel electrode layer may include a transparent conductive material such as ITO and IZO or a conductive material such as metal. 
     In the exemplary embodiment of the inventive concept, an example in which the main voltage line  471   a  of the first voltage wiring is positioned between the main voltage line  471   b  of the second voltage wiring and the display area DA is mainly described, but is not limited thereto. That is, positions of the first voltage wiring and the second voltage wiring may be changed. 
     In this case, on the contrary to the exemplary embodiment described above, the main voltage line  471   b  and the sub voltage line  472   b  of the second voltage wiring may be formed of different layers from each other and connected to each other through the contact assistant, and the main voltage line  471   a  and the sub voltage line  472   a  of the first voltage wiring may be formed of the same layer which is connected to each other. Further, when the sub voltage line  472   b  of the second voltage wiring may be connected to the input terminal of the corresponding thin film transistor of the stages ST 1 , ST 2 , . . . through a separate contact hole (not illustrated) and a contact assistant (not illustrated). 
     While this inventive concept has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the inventive concept is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.