Patent Publication Number: US-9852678-B2

Title: Display device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a divisional of U.S. patent application Ser. No. 14/489,421, filed Sep. 17, 2014, which claims priority to and the benefit of Korean Patent Application No. 10-2014-0040031, filed Apr. 3, 2014, the entire content of both of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Field 
     Embodiments of the present invention relate to a liquid crystal display (LCD). 
     2. Description of the Related Art 
     A display device displays an image corresponding to a video signal by adjusting light transmittance of liquid crystals. Such a liquid crystal display (LCD) includes an LCD panel in which liquid crystal cells are arranged in an active matrix pattern and driver circuits which drive the LCD panel. The active matrix LCD panel includes a plurality of data lines formed thereon, a plurality of gate lines crossing the data lines, and a plurality of pixel-driving thin-film transistors formed at crossing regions of the data lines and the gate lines. The driver circuits of the LCD include a data driver circuit for supplying data to the data lines of the LCD panel and a gate driver circuit for supplying scan pulses to the LCD panel. The driver circuits may further include a demultiplexer which is interposed between the data driver circuit and the data lines and distributes one output of the data driver circuit to a number of data lines. The demultiplexer reduces the number of outputs of the data driver circuit. Accordingly, the data driver circuit can be simplified, and the number of data input terminals of the LCD panel can be reduced. In addition, since the driver circuit is separated or spaced from the data lines (e.g., by a specific distance), the data lines may have different resistance values due to their different lengths. 
     The different resistance values may cause the data lines to have different signal delays. Accordingly, a different data voltage may be applied to each position, resulting in a vertical line defect (e.g., stain) and crosstalk due to coupling with a scan signal. 
     SUMMARY 
     Aspects of embodiments of the present invention provide a display device in which the size of a demultiplexer is adjusted in order to reduce a difference in signal delay. 
     Aspects of embodiments of the present invention also provide a display device in which a capacitor is added to a demultiplexer in order to reduce a difference in signal delay. 
     Aspects of embodiments of the present invention also provide a display device in which thicknesses of data lines are adjusted in order to reduce a difference in signal delay. 
     However, aspects of embodiments of the present invention are not restricted to the ones set forth herein. The above and other aspects of embodiments of the present invention will become more apparent to one of ordinary skill in the art to which embodiments of the present invention pertain by referencing the detailed description of embodiments of the present invention given below. 
     According to an embodiment of the present invention, there is provided a display device including a display panel including a plurality of gate lines on a substrate, a plurality of data lines crossing the gate lines, and a plurality of pixels, each of the pixels being coupled to one of the gate lines and to one of the data lines, a data driver configured to output data signals through a plurality of channel terminals, and a line selector configured to transmit the data signals to a plurality of data line blocks, each of the data line blocks including a plurality of data lines, wherein the line selector includes a plurality of thin-film transistors, and at least two of the thin-film transistors have different sizes. 
     The line selector may include a plurality of switching blocks, wherein each of the switching blocks is configured to transmit a data signal output from one of the channel terminals to a data line block coupled to the one of the channel terminals. 
     Each of the switching blocks may include a plurality of thin-film transistors, and the switching blocks may include equal numbers of thin-film transistors. 
     The display device may further include a signal controller configured to output a selection control signal for controlling the line selector. 
     The thin-film transistors may be configured to transmit the data signals to the data line blocks in response to the selection control signal. 
     The pixels may include a red pixel, a green pixel, and a blue pixel. 
     The line selector may include a plurality of switching blocks, and each of the switching blocks may include three thin-film transistors of an equal size. 
     The pixels may include a red pixel, a green pixel, a blue pixel, and a white pixel. 
     The line selector may include a plurality of switching blocks, and each of the switching blocks may include four thin-film transistors of an equal size. 
     According to another embodiment of the present invention, there is provided a display device including: a display panel including a plurality of gate lines on a substrate, a plurality of data lines crossing the gate lines, and a plurality of pixels, each of the pixels being coupled to one of the gate lines and to one of the data lines; a data driver configured to output data signals through a plurality of channel terminals; and a line selector configured to transmit the data signals to a plurality of data line blocks, each of the data line blocks including a plurality of data lines, wherein the line selector includes: a plurality of switching blocks; a plurality of selection control lines coupling the switching blocks and configured to transmit a selection control signal; and a compensation capacitor coupled to each of the selection control lines. 
     The display device may further include a signal controller configured to output the selection control signal for controlling the line selector. 
     Each of the switching blocks may include a plurality of thin-film transistors, and the switching blocks may include an equal number of thin-film transistors. 
     Each of the thin-film transistors may be configured to transmit a data signal to a corresponding data line block in response to the selection control signal. 
     The pixels may include a red pixel, a green pixel and a blue pixel, and each of the switching blocks may include three thin-film transistors of an equal size. 
     The pixels may include a red pixel, a green pixel, a blue pixel and a white pixel, and each of the switching blocks may include four thin-film transistors of an equal size. 
     According to another embodiment of the present invention, there is provided a display device including: a display panel including a plurality of gate lines formed on a substrate, a plurality of data lines crossing the gate lines, and a plurality of pixels, each of the pixels being coupled to one of the gate lines and to one of the data lines; a data driver configured to output data signals through a plurality of channel terminals; and a line selector configured to transmit the data signals to a plurality of data line blocks, each of the data line blocks including a plurality of data lines, wherein at least two of the gate lines have different widths. 
     The line selector may include a plurality of switching blocks, wherein each of the switching blocks is configured to transmit a data signal output from one of the channel terminals to a data line block coupled to the one of the channel terminals, and each of the switching blocks includes a plurality of thin-film transistors. 
     The display device may further include a signal controller configured to output the selection control signal for controlling the line selector, wherein each of the thin-film transistors is configured to transmit a data signal to a corresponding data line block in response to the selection control signal. 
     The pixels may include a red pixel, a green pixel and a blue pixel, and each of the switching blocks may include three thin-film transistors of an equal size. 
     The pixels may include a red pixel, a green pixel, a blue pixel and a white pixel, and each of the switching blocks may include four thin-film transistors of an equal size. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects and features of the present invention will become more apparent by describing in detail example embodiments thereof with reference to the attached drawings, in which: 
         FIG. 1  is a block diagram of a display device according to an embodiment of the present invention; 
         FIG. 2  is an equivalent circuit diagram of one pixel illustrated in  FIG. 1 ; 
         FIG. 3  is a plan view of a line selector according to an embodiment of the present invention; 
         FIG. 4  is an enlarged plan view of a portion shown in  FIG. 3 ; 
         FIG. 5  is a diagram illustrating the structure of a display panel according to an embodiment of the present invention; 
         FIG. 6  is a diagram illustrating the line selector shown in  FIG. 3 ; 
         FIG. 7  is a circuit diagram of the display device illustrated in  FIG. 1 ; 
         FIG. 8  is a plan view of line blocks according to an embodiment of the present invention; 
         FIG. 9  is a timing diagram of selection control signals transmitted to the line selector shown in  FIG. 6 ; 
         FIG. 10  is a diagram illustrating the structure of a display panel according to another embodiment of the present invention; 
         FIG. 11  is a diagram illustrating a line selector according to another embodiment of the present invention; 
         FIG. 12  is a plan view of the line selector illustrated in  FIG. 11 ; 
         FIG. 13  is a timing diagram of selection control signals transmitted to the line selector illustrated in  FIG. 11 ; 
         FIG. 14  is a block diagram of a display device according to another embodiment of the present invention; 
         FIG. 15  is a circuit diagram of a display device according to another embodiment of the present invention; 
         FIG. 16  is a circuit diagram of a display device according to another embodiment of the present invention; 
         FIG. 17  is a circuit diagram of a display device according to another embodiment of the present invention; 
         FIG. 18  is a circuit diagram of one pixel of a display device according to another embodiment of the present invention; 
         FIG. 19  is a plan view of a display device according to another embodiment of the present invention; and 
         FIG. 20  is a cross-sectional view taken along the line I-I′ shown in  FIG. 19 . 
     
    
    
     DETAILED DESCRIPTION 
     Aspects and features of the present invention and methods of accomplishing the same may be understood more readily by reference to the following detailed description of example embodiments and the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concept of the invention to those skilled in the art, and the present invention will only be defined by the appended claims, and equivalents thereof. Thus, in some embodiments, well-known structures and devices may not be shown in order not to obscure the description of the invention with unnecessary detail. Like numbers refer to like elements throughout. In the drawings, the thickness of layers and regions are exaggerated for clarity. 
     It will be understood that when an element or layer is referred to as being “on,” or “connected to” or “coupled to” another element or layer, it can be directly on or connected to or coupled to the other element or layer or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on” or “directly connected to” or “directly coupled to” another element or layer, there are no intervening elements or layers present. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     Spatially relative terms, such as “below,” “beneath,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. 
     Embodiments described herein will be described referring to plan views and/or cross-sectional views by way of ideal schematic views of the invention. Accordingly, the example views may be modified depending on manufacturing technologies and/or tolerances. Therefore, the embodiments of the present invention are not limited to those shown in the views, but include modifications in configuration formed on the basis of manufacturing processes. Therefore, example regions in figures have schematic properties, and shapes of regions shown in figures are examples of specific shapes of regions of elements and do not limit aspects of the present invention. 
     A “display device” described herein may encompass a liquid crystal display (LCD) or an organic light-emitting display (e.g., organic light emitting diode (OLED) display). 
     Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. 
       FIG. 1  is a block diagram of a display device according to an embodiment of the present invention.  FIG. 2  is an equivalent circuit diagram of one pixel illustrated in  FIG. 1 . 
     Referring to  FIGS. 1 and 2 , the display device according to the current embodiment includes a display panel  100 , a gate driver  200 , a data driver  300 , a line selector  400 , a signal controller  500 , and a driving voltage generator  600 . 
     The display panel  100  includes a plurality of gate lines G 1  through Gn extending along a direction (e.g., a row direction) and a plurality of data lines D 1  through Dm extending along another direction (e.g., a column direction) orthogonal to the above direction. The display panel  100  further includes pixel regions provided at crossing regions of the gate lines G 1  through Gn and the data lines D 1  through Dm. A pixel PX including a thin-film transistor T, a storage capacitor Cst, and a liquid crystal capacitor Clc is formed in each of the pixel regions. The display panel  100  includes a thin-film transistor substrate  11  on which the thin-film transistors T, the gate lines G 1  through Gn, the data lines D 1  through Dm and pixel electrodes P are formed, and a color filter substrate  120  on which a black matrix, color filters, and a common electrode are formed. 
     A thin-film transistor T includes a gate electrode, a source electrode and a drain electrode. The gate electrode is coupled to a gate line, the source electrode is coupled to a data line, and the drain electrode is coupled to a pixel electrode P. 
     The thin-film transistor T operates in response to a gate signal transmitted to the gate line and changes an electric field formed at both terminals of a liquid crystal capacitor Clc by transmitting a data signal received through the data line to the pixel electrode P. As a result, the arrangement of liquid crystals  130  is changed, thereby adjusting the transmittance of light supplied from a backlight. 
     The gate driver  200 , the data driver  300 , the line selector  400 , the signal controller  500  and the driving voltage generator  600  provide a plurality of signals for driving the display panel  100 . The gate driver  200  may be formed directly on the display panel  100 . The data driver  300  may be mounted on the display panel  100 . Alternatively, the data driver  3  may be mounted on a printed circuit board (PCB) and then electrically coupled to the display panel  1  by a flexible printed circuit board (FPCB). The line selector  400  may be mounted on the display panel  100 , and the signal controller  500  and the driving voltage generator  600  may be mounted on a PCB and electrically coupled to the display panel  100  by an FPCB. 
     The signal controller  500  receives an image signal, that is, pixel data R, G, B and W and control signals for controlling the display of the pixel data R, G, B and W from an external graphics controller. Examples of the control signals include a horizontal synchronization signal Hsync, a vertical synchronization signal Vsync, a main clock CLK, and a data enable signal DE. The signal controller  500  generates a gate control signal CON 1 , a data control signal CON 2 , and a selection control signal CON 3  by processing the pixel data R, G, B and W according to the operating condition of the display panel  100  and transmits the gate control signal CON 1 , the data control signal CON 2  and the selection control signal CON 3  to the gate driver  200 , the data driver  300  and the line selector  400 , respectively. Here, the gate control signal CON 1  includes a vertical synchronization start signal for instructing the output start of a gate turn-on voltage Von, a gate clock signal for controlling the output timing of the gate turn-on voltage Von, and an output enable signal for controlling the duration of the gate turn-on voltage Von. In addition, the data control signal CON 2  includes a horizontal synchronization start signal for informing the transmission start of pixel data, a load signal for instructing the application of a data voltage to a corresponding data line, an inversion signal for inverting the polarity of a gray voltage relative to a common voltage, and a data clock signal. The selection control signal CON 3  includes a plurality of selection control signals, e.g., first through third selection control signals CON 31  through CON 33  (see  FIG. 6 ), for controlling the operation of a plurality of switching devices included in each of line blocks that constitute the line selector  400 . 
     The driving voltage generator  600  generates various driving voltages for driving an LCD using external power input from an external power source. The driving voltage generator  600  generates a reference voltage AVDD, the gate turn-on voltage Von, a gate turn-off voltage Voff, and the common voltage. In response to the control signals from the signal controller  500 , the driving voltage generator  600  applies the gate turn-on voltage Von and the gate turn-off voltage Voff to the gate driver  200  and applies the reference voltage AVDD to the data driver  300 . Here, the reference voltage AVDD is used as a reference voltage needed to generate a gray voltage for driving liquid crystals. 
     The gate driver  200  applies the gate turn-on/turn-off voltage Von/Voff received from the driving voltage generator  600  to the gate lines G 1  through Gn in response to the gate control signal CON 1  received from the signal controller  500 . Accordingly, a corresponding thin-film transistor T can be controlled such that a gray voltage which will be applied to each pixel is applied to a corresponding pixel. 
     The data driver  300  generates a gray voltage using the data control signal CON 2  received from the signal controller  500  and the reference voltage AVDD received from the driving voltage generator  600 , and applies the gray voltage to each of a plurality of channel terminals CH 1  through CHk. 
       FIG. 3  is a plan view of a line selector  4  according to an embodiment of the present invention.  FIG. 4  is an enlarged plan view of a portion shown in  FIG. 3 . 
     Referring to  FIG. 3 , the line selector  4  according to the current embodiment may include a plurality of line blocks LB 1  through LBk. The line blocks LB 1  through LBk may receive data signals through a plurality of channel terminals CH 1  through CHk coupled to the data driver  300 . In addition, the line selector  400  may transmit the data signals received through the channel terminals CH 1  through CHk to the data lines D 1  through Dm in response to the selection control signal CON 3  received from the signal controller  500 . The line blocks LB 1  through LBk may include equal numbers of thin-film transistors. In  FIG. 5  which will be described later, each of the line blocks LB 1  through LBk includes three thin-film transistors. In  FIG. 10 , each of the line blocks LB 1  through LBk includes four thin-film transistors. However, the present invention is not limited thereto, and each of the line blocks LB 1  through LBk may include two or more thin-film transistors. The thin-film transistors may serve as switches that transmit data signals to the data lines D 1  through Dm. 
     A driver integrated circuit (IC) integrates the largest possible number of switching devices in a limited area. Therefore, the data driver  300  and the line selector  400  may be smaller in size than the display panel  100 . That is, as illustrated in  FIG. 3 , the line selector  400  is narrower than the display panel  100  and coupled to the data lines D 1  through Dm which are coupled to the display panel  100 . The data lines D 1  through Dm coupled to the line selector  400  may be arranged in a radial pattern. That is, a data line coupled to a pixel located far away from the line selector  400  is longer than a data line coupled to a pixel located adjacent to the line selector  400  and has a greater resistance value. The data lines D 1  through Dm do not overlap each other. 
     The arrangement of the line selector  400  and the display panel  100  is not limited to the arrangement of  FIG. 3 , and the line selector  400  may be placed at various positions. 
       FIG. 5  is a diagram illustrating the structure of a display panel  100  according to an embodiment of the present invention.  FIG. 6  is a diagram illustrating the line selector  400  shown in  FIG. 3 .  FIG. 7  is a circuit diagram of the display device illustrated in  FIG. 1 . 
     Referring to  FIG. 5 , the display panel  100  includes a plurality of gate lines G 1  through Gn extending along a row direction and a plurality of data lines D 1  through Dm extending along a column direction that crosses the row direction. In addition, the display panel  100  includes a plurality of pixels formed at crossing regions of the gate lines G 1  through Gn and the data lines D 1  through Dm. Each of the pixels is coupled to one of the gate lines G 1  through Gn and one of the data lines D 1  through Dm. 
     The pixels may include red, green and blue pixels R, G and B. In the current embodiment, the red pixel R, the green pixel G, and the blue pixel B may be arranged sequentially in each odd-numbered row. The red pixel R, the green pixel G and the blue pixel B can also be arranged in various patterns other than the arrangement pattern described in the current embodiment. For example, the red pixel R, the green pixel G, and the blue pixel B may be arranged such that pixels of the same color are not arranged successively in the row direction and the column direction. 
     The data lines D 1  through Dm are grouped into a plurality of data line blocks. Each of the data line blocks includes of a plurality of data lines, for example, three data lines. In one embodiment, each channel terminal CH is coupled to a corresponding data line block including three data lines by the line selector  400 . 
     Referring to the configuration and operation of the line selector  400  of  FIG. 6 , the line selector  400  includes a plurality of line blocks LB 1  through LBk. Here, the number of the line blocks LB 1  through LBk may be equal to the number of channel terminals of the data driver  300 . In addition, each of the line blocks LB 1  through LBk includes a plurality of switching devices, for example, three switching devices. The number of switching devices included in each of the line blocks LB 1  through LBk may be equal to the number of data lines included in each data line block. 
     Switching devices SW 11  through SW 13  coupled to a first data line block sequentially transmit a data signal output from a first channel terminal CH 1  to a plurality of data lines, and switching devices SW 21  through SW 23  coupled to a second data line block sequentially transmit a data signal output from a second channel terminal CH 2  to a plurality of data lines. The order in which a data signal is transmitted to a plurality of data lines included in the first data line block may be the same as the order in which a data signal is transmitted to a plurality of data lines included in the second data line block. However, the present invention is not limited thereto, and data signals can also be concurrently (e.g., simultaneously) transmitted to the data lines D 1  through Dm, respectively. In the current embodiment, each line block LBi includes three switching devices SWi 1  through SWi 3  in order to couple one channel terminal CHi to three data lines. The switching devices SWi 1  through SWi 3  may be transistors. However, the present invention is not limited thereto, and the switching devices SWi 1  through SWi 3  may be any other devices capable of performing a switching operation. 
     The first switching device SWi 1  included in an ith line block LBi may be driven in response to the first selection control signal CON 31 , the second switching device SWi 12  included in the ith line block LBi may be driven in response to the second selection control signal CON 32 , and the third switching device SWi 3  included in the ith line block LBi may be driven in response to the third selection control signal CON 33 . 
     Referring to a circuit formed in the data driver  300 , the line selector  400 , and the display panel  100  shown in  FIG. 7 , the data driver  300  may amplify a data signal DS and transmit the amplified data signal DS to one of the channel terminals CH 1  through CHk. The operation of the data driver  300  may be in accordance with the driving principle of a general data driver, and thus a detailed description thereof will be omitted. 
     The line selector  400  may include the line blocks LB 1  through LBk, and each of the line blocks LB 1  through LBk may include the switching devices SWi 1  through SWi 3  respectively corresponding to the red pixel R, the green pixel G, and the blue pixel B. The switching devices SWi 1  through SWi 3  respectively corresponding to the red pixel R, the green pixel G and the blue pixel B may transmit a data signal to a plurality of data lines in response to the first through third selection control signals CON 31  through CON 33 , respectively. The switching devices SWi 1  through SWi 3  may respectively include coupling capacitors CC 1  through CC 3  and line capacitors CD 1  through CD 3 . A coupling capacitor and a line capacitor may stably maintain the magnitude of a voltage applied to a switching device and maintain a voltage level at which the switching device can be turned on. Line resistors RL 1  through RL 3  included in the line selector  4  may have resistance values that are proportional to lengths of data lines corresponding to individual pixels. The sizes of the line resistors RL 1  through RL 3  may be determined by the lengths and thicknesses of the data lines extending from the line selector  4 . That is, different line blocks LB 1  through LBk may have different line resistances and, accordingly, different delay times. 
     The display panel  1  may include pixel resistors RP 1  through RP 3  and pixel capacitors CP 1  through CP 3 . The pixel resistors RP 1  through RP 3  may have resistance values of the red pixel R, the green pixel G, and the blue pixel B, and the pixel capacitors CP 1  through CP 3  may be capacitors respectively corresponding to capacitance values of the red pixel R, the green pixel G and the blue pixel B. Each of the pixel capacitors CP 1  through CP 3  may be, for example, a storage capacitor Cst or a liquid crystal capacitor Clc. 
     That is, the entire circuit centered on the line selector  400  can be roughly understood from the circuit diagram shown in  FIG. 7 . 
       FIG. 8  is a plan view of line blocks LB according to an embodiment of the present invention. 
     Referring to  FIG. 8 , the line blocks LB according to the current embodiment include an equal number of switching devices of an equal size. At least two of the line blocks LB may include switching devices of different sizes. More specifically, the line selector  400  may include a first control line  10 , a second control line  20 , and a third control line  30  to which the first through third selection control signals CON 31  through CON 33  are transmitted. In addition, the line selector  400  may include a first gate electrode  11 , a second gate electrode  12 , and a third gate electrode  13  which are coupled to the first control line  10 , the second control line  20 , and the third control line  30  by bridges  81  through  83 , respectively. The first gate electrode  11 , the second gate electrode  12 , and the third gate electrode  13  may be electrically coupled to the first control line  10 , the second control line  20 , and the third control line  30  by contact holes  14   a ,  14   b ,  15   a ,  15   b ,  16   a  and  16   b  formed at the bridges  81  through  83 . 
     Each of the line blocks LB may receive a data signal DS through a channel terminal CH, and the channel terminal CH may transmit the data signal DS to a source pad  51 . The channel terminal CH may be electrically coupled to the source pad  51  by a contact hole  53  formed on the source pad  51 . The source pad  51  may include a first source electrode  61 , a second source electrode  62 , and a third source electrode  63 . The first source electrode  61 , the second source electrode  62  and the third source electrode  63  may be formed on the first gate electrode  11 , the second gate electrode  12 , and the third gate electrode  13 . The first source electrode  61 , the second source electrode  62 , and the third source electrode  63  may be electrically coupled to the source pad  51  by contact holes  54  through  56  formed on the source pad  51 . 
     Each of the line blocks LB may include a first drain electrode  71 , a second drain electrode  72 , and a third drain electrode  73 . The first drain electrode  71 , the second drain electrode  72 , and the third drain electrode  73  may be formed on the first gate electrode  11 , the second gate electrode  12 , and the third gate electrode  13 . Each of the line blocks LB may transmit the received data signal DS to individual data lines through the first drain electrode  71 , the second drain electrode  72 , and the third drain electrode  73 . 
     That is, the first through third drain electrodes  71  through  73  and the first through third source electrodes  61  through  63  may be formed on the first through third gate electrodes  11  through  13 , and width/length ratio (W/L) of a thin-film transistor may be determined by an overlapping area between a drain electrode and a gate electrode and an overlapping area between a source electrode and the gate electrode. Generally, the thin-film transistor may be a metal-oxide-semiconductor field-effect transistor (MOSFET), and the W/L of the MOSFET may determine the magnitude of an electric current flowing through the MOSFET in response to a voltage applied to the MOSFET. That is, the magnitude of the electric current flowing through the thin-film transistor can be controlled by adjusting the W/L of the thin-film transistor, thereby controlling a slew rate. 
     In  FIG. 8 , thin-film transistors included in the first line block LB 1 , thin-film transistors included in the second line block LB 2 , and thin-film transistors included in the third line block LB 3  have different sizes. Therefore, data lines coupled to each of the line blocks LB 1  through LB 3  may have different slew rates from slew rates of data lines coupled to the other line blocks. When the same data voltage is applied to each data line, slew rates of pixels coupled to each data line may vary according to the length of each data line from the line selector  400  to the pixels. As a result, vertical lines can be observed. Therefore, the slew rates of the pixels can be improved by designing the sizes of thin-film transistors included in each line block in view of the slew rates of pixels coupled to each measured data line. 
       FIG. 9  is a timing diagram of the selection control signals CON 31  through CON 33  transmitted to the line selector  400  shown in  FIG. 6 . Referring to  FIG. 9 , the first switching device SWi 1  included in the ith line block LBi may be driven by the first selection control signal CON 31 , the second switching device SWi 2  may be driven by the second selection control signal CON 32 , and the third switching device SWi 3  may be driven by the third selection control signal CON 33 . Each of the selection control signals CON 31  through CON 33  may be repeatedly transmitted during each period  1 H of a gate signal. 
     Pulses of the selection control signal CON 3  may be input in the order of the first selection control signal CON 31 , the second selection control signal CON 32 , and the third selection control signal CON 33  as illustrated in  FIG. 9 . However, the present invention is not limited thereto, and the pulses of the selection control signal CON 3  may also be input in the order of the third selection control signal CON 33 , the second selection control signal CON 32 , and the first selection control signal CON 31 . That is, in other embodiments, the order in which the pulses are input may be determined differently. 
       FIG. 10  is a diagram illustrating the structure of a display panel  100  according to another embodiment of the present invention.  FIG. 11  is a diagram illustrating a line selector  400  according to another embodiment of the present invention.  FIG. 12  is a plan view of the line selector  400  illustrated in  FIG. 11 .  FIG. 13  is a timing diagram of selection control signals CON 31  through CON 34  transmitted to the line selector  400  illustrated in  FIG. 11 . 
     Referring to  FIG. 10 , the liquid crystal display panel  100  includes a plurality of gate lines G 1  through Gn extending along a row direction and a plurality of data lines D 1  through Dm extending along a column direction that crosses the row direction. In addition, the display panel  100  includes a plurality of pixels formed at crossing regions of the gate lines G 1  through Gn and the data lines D 1  through Dm. Each of the pixels is coupled to one of the gate lines G 1  through Gn and one of the data lines D 1  through Dm. 
     The pixels may include red, green, blue and white pixels R, G, B and W. In the current embodiment, the red pixel R, the green pixel G, the blue pixel B and the white pixel W may be arranged sequentially in each odd-numbered row. The red pixel R, the green pixel G, the blue pixel B and the white pixel W may also be arranged in various pentile patterns other than the arrangement pattern described in the current embodiment. For example, the red pixel R, the green pixel G, the blue pixel B, and the white pixel W may be arranged such that pixels of the same color are not arranged successively in the row direction and the column direction. 
     The data lines D 1  through Dm are grouped into a plurality of data line blocks. Each of the data line blocks includes a plurality of data lines, for example, four data lines. Here, each channel terminal CH is coupled to a corresponding data line block including four data lines by the line selector  400 . 
     Referring to the configuration and operation of the line selector  400  shown in  FIG. 11 , the line selector  400  includes a plurality of line blocks LB 1  through LBk. Here, the number of the line blocks LB 1  through LBk may be equal to the number of channel terminals of the data driver  300 . In addition, each of the line blocks LB 1  through LBk includes a plurality of switching devices, for example, four switching devices. The number of switching devices included in each of the line blocks LB 1  through LBk may be equal to the number of data lines included in each data line block. 
     Switching devices SW 11  through SW 14  included in the first line block LB 1  sequentially transmit a data signal output from a first channel terminal CH 1  to a plurality of data lines, and switching devices SW 21  through SW 24  included in the second line block LB 2  sequentially transmit a data signal output from a second channel terminal CH 2  to a plurality of data lines. The order in which a data signal is transmitted to a plurality of data lines included in the first data line block may be the same as the order in which a data signal is transmitted to a plurality of data lines included in the second data line block. However, the present invention is not limited thereto, and data signals may also be concurrently (e.g., simultaneously) transmitted to the data lines D 1  through Dm, respectively. 
     In the current embodiment, each line block LBi includes four switching devices SWi 1  through SWi 4  in order to couple one channel terminal CHi to four data lines. The switching devices SWi 1  through SWi 4  may be transistors. However, the present invention is not limited thereto, and the switching devices SWi 1  through SWi 4  may be any other devices capable of performing a switching operation. 
     The first switching device SWi 1  included in an ith line block LBi may be driven in response to a first selection control signal CON 31 , the second switching device SWi 12  included in the ith line block LBi may be driven in response to a second selection control signal CON 32 , the third switching device SWi 3  included in the ith line block LBi may be driven in response to a third selection control signal CON 33 , and the fourth switching device SWi 4  included in the ith line block LBi may be driven in response to a fourth selection control signal CON 34 . 
       FIG. 12  is a plan view of line blocks LB according to another embodiment of the present invention. 
     Referring to  FIG. 12 , the line blocks LB according to the current embodiment include equal numbers of switching devices of an equal size. At least two of the line blocks LB may include switching devices of different sizes. More specifically, the line selector  400  may include a first control line  10 , a second control line  20 , a third control line  30 , and a fourth control line  40  to which the first through fourth selection control signals CON 31  through CON 34  are transmitted. In addition, the line selector  400  may include a first gate electrode  11 , a second gate electrode  12 , a third gate electrode  13  and a fourth gate electrode  14  which are coupled to the first control line  10 , the second control line  20 , the third control line  30 , and the fourth control line  40  by bridges  81  through  84 , respectively. The first gate electrode  11 , the second gate electrode  12 , the third gate electrode  13 , and the fourth gate electrode  14  may be electrically coupled to the first control line  10 , the second control line  20 , the third control line  30 , and the fourth control line  40  by contact holes  14   a ,  14   b ,  15   a ,  15   b ,  16   a ,  16   b ,  17   a  and  17   b  formed on the bridges  81  through  84 . 
     Each of the line blocks LB may receive a data signal DS through a channel terminal CH, and the channel terminal CH may transmit the data signal DS to a source pad  51 . The channel terminal CH may be electrically coupled to the source pad  51  by a contact hole  53  formed on the source pad  51 . The source pad  51  may include a first source electrode  61 , a second source electrode  62 , a third source electrode  63 , and a fourth source electrode  64 . The first source electrode  61 , the second source electrode  62 , the third source electrode  63 , and the fourth source electrode  64  may be formed on the first gate electrode  11 , the second gate electrode  12 , the third gate electrode  13 , and the fourth gate electrode  14 . The first source electrode  61 , the second source electrode  62 , the third source electrode  63 , and the fourth source electrode  64  may be electrically coupled to the source pad  51  by contact holes  54  through  57  formed on the source pad  51 . 
     Each of the line blocks LB may include a first drain electrode  71 , a second drain electrode  72 , a third drain electrode  73 , and a fourth drain electrode  74 . The first drain electrode  71 , the second drain electrode  72 , the third drain electrode  73 , and the fourth drain electrode  74  may be formed on the first gate electrode  11 , the second gate electrode  12 , the third gate electrode  13 , and the fourth gate electrode  14 . Each of the line blocks LB may transmit the received data signal DS to individual data lines through the first drain electrode  71 , the second drain electrode  72 , the third drain electrode  73 , and the fourth drain electrode  74 . 
     That is, the first through fourth drain electrodes  71  through  74  and the first through fourth source electrodes  61  through  64  may be formed on the first through fourth gate electrodes  11  through  14 , and the W/L of a thin-film transistor may be determined by an overlapping area between a drain electrode and a gate electrode and an overlapping area between a source electrode and the gate electrode. Generally, the thin-film transistor may be a MOSFET, and the W/L of the MOSFET may determine the magnitude of an electric current flowing through the MOSFET in response to a voltage applied to the MOSFET. That is, the magnitude of the electric current flowing through the thin-film transistor may be controlled by adjusting the W/L of the thin-film transistor, thereby controlling a slew rate. 
     In  FIG. 12 , thin-film transistors included in a first line block LB 1 , thin-film transistors included in a second line block LB 2 , and thin-film transistors included in a third line block LB 3  have different sizes. Therefore, data lines coupled to each of the line blocks LB 1  through LB 3  may have different slew rates from slew rates of data lines coupled to the other line blocks. When the same data voltage is applied to each data line, slew rates of pixels coupled to each data line may vary according to the length of each data line from the line selector  400  to the pixels. As a result, vertical lines can be observed. Therefore, the slew rates of the pixels can be improved by designing the sizes of thin-film transistors included in each line block in view of the slew rates of pixels coupled to each measured data line. 
     Referring to  FIG. 13 , a first switching device SWi 1  included in an ith line block LBi may be driven by the first selection control signal CON 31 , a second switching device SWi 2  may be driven by the second selection control signal CON 32 , a third switching device SWi 3  may be driven by the third selection control signal CON 33 , and a fourth switching device SWi 4  may be driven by the fourth selection control signal CON 34 . Each of the selection control signals CON 31  through CON 34  may be repeatedly transmitted during each period  1 H of a gate signal. 
     Pulses of a selection control signal CON 3  may be input in the order of the first selection control signal CON 31 , the second selection control signal CON 32 , the third selection control signal CON 33 , and the fourth selection control signal CON 34  as illustrated in  FIG. 13 . However, the present invention is not limited thereto, and the pulses of the selection control signal CON 3  may also be input in the order of the fourth selection control signal CON 34 , the third selection control signal CON 33 , the second selection control signal CON 32 , and the first selection control signal CON 31 . That is, in other embodiments, the order in which the pulses are input may be determined differently (e.g., arbitrarily). 
       FIG. 14  is a block diagram of a display device according to another embodiment of the present invention. 
     Referring to  FIG. 14 , a display panel may have a circular or polygonal shape instead of a rectangular shape. The circular display panel may also operate in the same way as the rectangular display panel  1  illustrated in  FIG. 1 . That is, a plurality of data lines D 1  through Dm may extend from a plurality of line blocks LB along a column direction, and a plurality of gate lines G 1  through Gn may extend along a row direction perpendicular to the column direction. However, the number of pixels coupled to each gate line and the number of pixels coupled to each data line may be different. Gate signal application units GU 1  through GUn may transmit gate signals to the gate lines G 1  through Gn. 
     In a rectangular liquid crystal panel, an equal number of pixels are coupled to each data line. Accordingly, there may be no significant difference between slew rates of the line blocks LB. However, in the circular display panel illustrated in  FIG. 14 , a different number of pixels are coupled to each data line. Accordingly, there may be a significant difference between the slew rates of the line blocks LB. That is, the sizes of thin-film transistors included in each line block LB may be designed in view of a slew rate of each measured data line. 
       FIG. 15  is a circuit diagram of a display device according to another embodiment of the present invention. 
     Referring to a circuit formed in a data driver  300 , a line selector  400 , and a display panel  100  shown in  FIG. 15 , the data driver  300  may amplify a data signal DS and transmit the amplified data signal DS to one of channel terminals CH 1  through CHk. The operation of the data driver  300  may be in accordance with the driving principle of a general data driver, and thus a detailed description thereof will be omitted. 
     The line selector  400  may include a plurality of line blocks LB 1  through LBk, and each of the line blocks LB 1  through LBk may include a plurality of switching devices SW 1  through SWk. The switching devices SW 1  through SWk may transmit a data signal to a plurality of data lines in response to the same selection control signal CON 3 . For example, the switching devices SW 1  through SWk of each line block LB may be controlled by a first selection control signal, a second selection control signal, or a third selection control signal. The switching devices SW 1  through SWk may respectively include coupling capacitors CC 1  through CCk and line capacitors CD 1  through CDk. A coupling capacitor and a line capacitor may stably maintain the magnitude of a voltage applied to a switching device and maintain a voltage level at which the switching device can be turned on. Line resistors RL 1  through RLk included in the line selector  4  may have resistance values that are proportional to lengths of data lines corresponding to individual pixels. The sizes of the line resistors RL 1  through RLk may be determined by the lengths and thicknesses of the data lines extending from the line selector  400 . That is, different line blocks LB 1  through LBk may have different line resistances and, accordingly, different delay times. 
     A node coupled to the selection control signal CON 3  may include a compensation capacitor CCP. The compensation capacitor CCP added outside the line blocks LB (inside the line selector  400 ) may include a greater amount of electric charge than the coupling capacitors CC 1  through CCk and the line capacitors CD 1  through CDk. Therefore, the magnitude of a voltage applied to each switching device can be maintained more stably. In addition, since τ (a time constant)=r*c varies according to the capacitance of the compensation capacitor CCP, a slew rate can be adjusted. 
     The display panel  100  may include pixel resistors RP 1  through RP 3  and pixel capacitors CP 1  through CP 3 . Each of the pixel resistors RP 1  through RP 3  may have a resistance value of a corresponding pixel, and each of the pixel capacitors CP 1  through CP 3  may be a capacitor corresponding to a capacitance value of a corresponding pixel. Each of the pixel capacitors CP 1  through CP 3  may be, for example, a storage capacitor Cst or a liquid crystal capacitor Clc. 
       FIG. 16  is a circuit diagram of a display device according to another embodiment of the present invention. 
       FIG. 16  is similar to  FIG. 15 . However, compensation capacitors CCP′ may be added in parallel in both directions in which a selection control signal is transmitted. Capacitance of various magnitudes can be obtained by adjusting the sizes of the compensation capacitors CCP′. 
       FIG. 17  is a circuit diagram of a display device according to another embodiment of the present invention. 
     Referring to  FIG. 17 , compensation capacitors CCP 1  through CCPk may be added in parallel to each line block LB. With the addition of the compensation capacitors CCP 1  through CCPk to each line block LB, electric charges can be stably supplied to line blocks LB formed in the middle of a line selector  400 , and a slew rate of each line block LB can be adjusted easily. However, the present invention is not limited thereto, and a compensation capacitor CCP can also be added to each plurality of line blocks LB, and the number of compensation capacitors CCP to be added may be suitably adjusted as desired by a user. 
       FIG. 18  is a circuit diagram of one pixel PX of a display device according to another embodiment of the present invention. 
     Referring to  FIG. 18 , the pixel PX includes a driving transistor T 1  and an organic light-emitting diode OLED. The driving transistor T 1  has a gate G coupled to a first node N 1 , a source S coupled to a second node N 2 , and a drain D coupled to a third node N 3 . The driving transistor T 1  can control a driving current Id. The driving current Id may be an electric current flowing from the source S of the driving transistor T 1  to the drain D of the driving transistor T 1 . The driving current Id may be an electric current flowing through the organic light-emitting diode OLED, and the organic light-emitting diode OLED may emit light at a luminance level corresponding to the driving current Id. The magnitude of the driving current Id may correspond to a potential difference between the gate G and the source S of the driving transistor T 1  and a potential difference between the drain D and the source S of the driving transistor T 1 . For example, the greater the potential difference between the gate G and the source S, the greater the driving current Id, and the greater the potential difference between the drain D and the source S, the greater the driving current Id. Assuming that the potential difference between the gate G and the source S is maintained constant, the driving current Id may be controlled according to the potential difference between the drain D and the source S. A switching transistor T 2  may apply a data voltage to the source S of the driving transistor T 1 . Specifically, the switching transistor T 2  may apply a data voltage of a data line coupled to a source S of the switching transistor T 2  to the source S of the driving transistor T 1  in response to a scan signal. The magnitude of the driving current Id of each pixel may vary according to the magnitude of a voltage applied to a corresponding data line. In addition, the width of each data line for applying a voltage to pixels may be adjusted to control the resistance of the data line and control slew rates of pixels coupled to the data line and a slew rate of a line selector. 
       FIG. 19  is a plan view of a display device according to another embodiment of the present invention. 
     Referring to  FIG. 19 , a panel includes a plurality of data lines  121  through  123  extending along a column direction and a gate line  150  extending along a row direction. The data lines  121  through  123  cross the gate line  150 , and a plurality of pixels PX are defined by the data lines  121  through  123  and the gate line  150 . The panel has a general shape of a display device and may be a panel of an LCD, an organic light-emitting display, etc. Each of the pixels PX may include a plurality of thin-film transistors and display a signal, which corresponds to a data voltage received from a data line, in response to a signal transmitted to the gate line  150 . 
     The data lines  121  through  123  may not have equal widths and thus may have different resistance values. Hence, resistances of the data lines  121  through  123  can be controlled by adjusting the widths of the data lines  121  through  123 , and slew rates of the pixels PX coupled to the data lines  121  through  123  and a slew rate of a line selector can also be controlled by adjusting the widths of the data lines  121  through  123 . 
       FIG. 20  is a cross-sectional view taken along the line I-I′ shown in  FIG. 19 . 
     Referring to  FIG. 2 , a gate insulating layer  111  may be formed on a substrate  101 , and gate electrodes  121  through  123  may be formed on the gate insulating layer  111 . First through fourth insulating layers  112  through  115  may be formed on the gate electrodes  121  through  123  and on the gate insulating layer  111 . A plurality of pixel electrodes P may be formed on the first through fourth insulating layers  112  through  115 . 
     The gate electrodes  121  through  123  may have different widths. The first gate electrode  121  may have a first width W 1 , the second gate electrode  122  may have a second width W 2 , and the third gate electrode  123  may have a third width W 3 . The first width W 1 , the second width W 2 , and the third width W 3  may be different from each other. 
     That is, a display device structured to reduce a difference in signal delay of a line selector can be provided. 
     In addition, a display device structured to increase (e.g., improve) the reliability of the line selector can be provided. 
     Furthermore, a display device structured to reduce a difference in signal delay between data lines can be provided. 
     However, the effects of the present invention are not restricted to the ones set forth herein. The above and other effects of the present invention will become more apparent to one of daily skill in the art to which the present invention pertains by referencing the claims, and equivalents thereof. 
     While the present invention has been particularly shown and described with reference to example embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made herein without departing from the spirit and scope of the present invention as defined by the following claims, and equivalents thereof. It is therefore desired that the present embodiments be considered in all respects as illustrative and not restrictive, reference being made to the appended claims, and equivalents thereof, rather than the foregoing description, to indicate the scope of the invention.