This application claims priority to Korean Patent Application No. 10-2008-0115297, filed on Nov. 19, 2008, and all the benefits accruing therefrom under 35 U.S.C. §119, the contents of which in its entirety are herein incorporated by reference.
1. Field of the Invention
The present invention relates to a display apparatus and a method of driving the same, and more particularly, to a display apparatus with substantially improved display quality and a method of driving the display apparatus.
2. Description of the Related Art
Display apparatus such as an organic light emitting device (OLED), a plasma display panel (PDP), and a liquid crystal display (LCD) have been actively developed as substitutes for the cathode ray tube (CRT), which may be heavy and large. A PDP is a device that displays characters or images using plasma generated by a gas-discharge, and an OLED is a device that displays characters or images using electroluminescence of a specific organic material or high molecular weight polymeric compounds. A liquid crystal display (“LCD”) typically includes a first display substrate, a second display substrate and a dielectrically anisotropic liquid crystal layer interposed between the first display substrate and the second display substrate. The first substrate has a plurality of pixel electrodes disposed thereon. The second substrate has a common electrode disposed thereon. Otherwise, the first substrate may have a common electrode disposed thereon. The plurality of pixel electrodes is arranged in a substantially matrix pattern and is connected to switching devices such as thin-film transistors (“TFTs”), for example. A data voltage is applied to a corresponding pixel electrode. The common electrode receives a common voltage. The liquid crystal layer, interposed between the first substrate and the second substrate, forms a liquid crystal capacitor, and the liquid crystal capacitor and the switching device connected to the liquid crystal capacitor form a basic unit of a pixel.
The LCD generates an electric field in the liquid crystal layer by applying voltages to the pixel electrodes and the common electrode and controls an intensity of the electric field to control an amount of light transmitted through the liquid crystal layer. Thus, the LCD displays a desired image. However, when an electric field aligned in a given direction is applied to the liquid crystal layer for an extended amount of time, a display quality of the LCD is substantially degraded. To prevent this problem, a polarity of the data voltage is inverted, with respect to a polarity of the common voltage, based on units of frames, rows, columns or pixels, for example. However, when the polarity of the data voltage is inverted as described above, a response time of liquid crystal molecules in the liquid crystal layer is substantially reduced. Thus, a time required for the liquid crystal capacitor to charge to a target voltage level is substantially increased, thereby causing screen blurring in the LCD.
To address this problem, driving methods such as a black insertion driving method in which black images are inserted into specific regions of the screen of an LCD, or, alternatively, an impulsive driving method, have been developed. However, when a plurality of gate lines are divided into a plurality of groups and a gate-on signal is transmitted to each of the groups such that black data (or impulsive data) is inserted into the groups, a large difference between a normal data output time of a last gate line in each group and a normal data output time of a first gate line in a next group develops. Thus, bright lines, caused by a discontinuous difference in gray level, are formed, thereby substantially degrading display quality of the LCD.
Exemplary embodiments of the present invention provide a display apparatus with substantially improved display quality.
Exemplary embodiments of the present invention also provide a method of driving an display apparatus with substantially improved display quality.
According to an exemplary embodiment of the present invention, an display apparatus includes: a display panel including gate lines, data lines which cross the gate lines and pixels electrically connected to the gate lines and the data lines and which display images; a gate driver electrically connected to the gate lines and which transmits a first gate signal and a second gate signal to the gate lines; and a data driver electrically connected to the data lines and which transmits normal data voltages and impulsive data voltages to the data lines. The pixels receive the normal data voltages in response to the first gate signal, and receive the impulsive data voltages in response to the second gate signal. The gate lines are divided into at least one first group and at least one second group disposed adjacent to the at least one first group. An order in which the first gate signal is transmitted to the gate lines in the at least one first group is different from an order in which the first gate signal is transmitted to the gate lines in the at least one second group.
According to an exemplary embodiment of the present invention, a display apparatus includes: a display panel comprising: gate lines, data lines which cross the gate lines and pixels electrically connected to the gate lines and the data lines, which display an image; a gate driver electrically connected to the gate lines, which transmits a first gate signal and a second gate signal to the gate lines; a data driver electrically connected to the data lines, which transmits normal data voltages and impulsive data voltages to the data lines; and a signal controller. the pixels receive the normal data voltages in response to the first gate signal. the pixels receive the impulsive data voltages in response to the second gate signal. the gate lines are divided into at least one first group and at least one second group. The at least one first group is disposed adjacent to the at least one second group. And an order in which the first gate signal is transmitted to the gate lines in the at least one first group is different from an order in which the first gate signal is transmitted to the gate lines in the at least one second group the signal controller receives original image signals. the signal controller generates the normal data signals which is corresponding to the normal data voltages, by changing an order of the original image signals based on at least one of the order in which the first gate signal is transmitted to the gate lines in the at least one first group and the order in which the first gate signal is transmitted to the gate lines in the at least one second group.
According to an exemplary embodiment of the present invention, a method of driving an display apparatus includes: providing a display panel including gate lines, data lines which cross the gate lines and pixels electrically connected to the gate lines and the data lines and which display images; transmitting a first gate signal and a second gate signal to the gate lines; and transmitting normal data voltages and impulsive data voltages to the data lines. The pixels receive the normal data voltages in response to the first gate signal, and receive the impulsive data voltages in response to the second gate signal. The gate lines are divided into at least one first group and at least one second group disposed adjacent to the at least one first group. An order in which the first gate signal is transmitted to the gate lines in the at least one first group is different from an order in which the first gate signal is transmitted to the gate lines in the at least one second group.
The above and other aspects, features and advantages of the present invention will become more readily apparent by describing in further detail exemplary embodiments thereof with reference to the accompanying drawings, in which:
The invention will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. The present invention may, however, be embodied in many different forms and should not be construed as 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 scope of the invention to those skilled in the art. Like reference numerals refer to like elements throughout.
It will be understood that when an element is referred to as being “on” another element, it can be directly on the other element or intervening elements may be present therebetween. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
It will be understood that although the terms “first,” “second,” “third” etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including,” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components and/or groups thereof.
Furthermore, relative terms, such as “lower” or “bottom” and “upper” or “top” may be used herein to describe one element's relationship to other elements as illustrated in the Figures. It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. For example, if the device in one of the figures is turned over, elements described as being on the “lower” side of other elements would then be oriented on the “upper” side of the other elements. The exemplary term “lower” can, therefore, encompass both an orientation of “lower” and “upper,” depending upon the particular orientation of the figure. Similarly, if the device in one of the figures were turned over, elements described as “below” or “beneath” other elements would then be oriented “above” the other elements. The exemplary terms “below” or “beneath” can, therefore, encompass both an orientation of above and below.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning which is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Exemplary embodiments of the present invention are described herein with reference to cross section illustrations which are schematic illustrations of idealized embodiments of the present invention. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments of the present invention should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes which result, for example, from manufacturing. For example, a region illustrated or described as flat may, typically, have rough and/or nonlinear features. Moreover, sharp angles which are illustrated may be rounded. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region and are not intended to limit the scope of the present invention.
Hereinafter, a liquid crystal display (“LCD”) and a method of driving the same according to an exemplary embodiment of the present invention will be described in further detail with reference to the accompanying drawings.
Referring to
The display panel 300 includes the first through (3n)th gate lines G1 through G3n, respectively, first through mth data lines D1 through Dm, respectively, and a plurality of pixels PX. The first through (3n)th gate lines G1 through G3n extend in a substantially first direction and substantially parallel to each other, and the first through mth data lines D1 through Dm extend in a substantially second direction and substantially parallel to each other. In an exemplary embodiment, the plurality of pixels PX are disposed in regions in which the first through (3n)th gate lines G1 through G3n cross the first through mth data lines D1 through Dm, respectively. The gate driver 400 transmits gate signals to the first through (3n)th gate lines G1 through G3n, and the data driver 500 transmits data voltages to the first through mth data lines D1 through Dm. The plurality of pixels PX display images in response to the data voltages, respectively.
In an exemplary embodiment, the gate signals are transmitted to the gate lines G1 through G3n and include first gate signals and second gate signals. In addition, the data voltages applied to the data lines D1 through Dm include normal data voltages and impulsive data voltages. The pixels PX receive the normal data voltages in response to the first gate signals, and the pixels PX receive the impulsive data voltages in response to the second gate signals.
More specifically, the first through (3n)th gate lines G1 through G3n are divided into a plurality of sections (e.g., parts), and each of the sections (e.g., parts) is defined as a first group or a second group. For example, the first through (3n)th gate lines G1 through G3n, disposed sequentially on the display panel 300, are divided into three sections A, B and C. That is, the first through nth gate lines G1 through Gn may be included in section A, the (n+1)th through (2n)th gate lines G(n+1) through G2n may be included in section B, and the (2n+1)th through (3n)th gate lines G(2n+1) through G3n may be included in section C. For ease of description, the sections A, B and C will hereinafter be referred to as parts A, B and C, respectively.
In an exemplary embodiment, the part A and the part C are included in the first group, and the part B is included in the second group. Thus, although the part A and the part B are adjacent to each other, part A may be in the first group while the part B is in the second group. Likewise, although the parts B and the part C are adjacent to each other, the part B is in the second group while the part C is in the first group.
An order in which the first gate signals are sequentially and respectively transmitted to gate lines included in the first group is different from an order in which the first gate signals are sequentially and respectively transmitted to gate lines included in the second group. Specifically, the order in which the first gate signals are sequentially and respectively transmitted to the first through nth gate lines G1 through Gn (included in the part A, which is in the first group) and the order in which the first gate signals are sequentially and respectively transmitted to the (2n+1)th through (3n)th gate lines G(2n+1) through G3n (included in the part C, which is in the first group) are different from the order in which the first gate signals are sequentially and respectively transmitted to the (n+1)th through (2n)th gate lines G(n+1) through G2n (included in the part B, which is in the second group). More particularly, the first gate signals may sequentially and respectively be transmitted to the first through nth gate lines G1 through Gn in a first order, to the (2n)th through (n+1)th gate lines G2n through G(n+1) in a second order, and to the (2n+1)th through (3n)th gate lines G(2n+1) through G3n in a third order, as will be described in further detail below with reference to
As will also be described in further detail below, the signal controller 600 receives original image signals R, G and B and outputs display data signals DAT to the data driver 500. Moreover, the data driver 500 outputs data voltages (e.g., the normal data voltages and the impulsive data voltages) which correspond to the display data signals DAT. Specifically, the signal controller 600 may receive the original image signals R, G and B, change an arrangement order of the original image signals R, G and B based on the order in which the first gate signals are sequentially and respectively transmitted to the first through (3n)th gate lines G1 through G3n, as described above, and generate the normal data signals. Generating the normal data signals by changing the arrangement order of the original image signals R, G and B will be described in further detail below with reference to
As shown in
Referring now to
Referring again to
The gate driver 400 according to an exemplary embodiment receives the gate control signals CONT1 from the signal controller 600 and transmits the first gate signal and the second gate signal to the first through (3n)th gate lines G1 through G3n. In an exemplary embodiment, the first gate signal and the second gate signal are a combination of a gate-on voltage Von and a gate-off voltage Voff provided by a gate on/off voltage generator (not shown). In an exemplary embodiment, for example, the first gate signals may be gate-on voltages corresponding to the normal image data, while the second gate signals may be gate-on voltages corresponding to the impulsive image data. An operation of the first gate signal and the second gate signal will be described in further detail below with reference to
The data driver 500 receives the data control signals CONT2 from the signal controller 600 and transmits the data voltages, which correspond to the display data signals DAT, to the first through mth data lines D1 through Dm. The data voltages corresponding to the display data signals DAT are provide from the grayscale voltage generator 700. In an exemplary embodiment, the display data signals DAT include the normal data signals and the impulsive data signals. As a result, the data voltages include the normal data voltages and the impulsive data voltages corresponding to the normal data signals and the impulsive data signals, respectively. In an exemplary embodiment, the impulsive data signals are black data signals, for example, but alternative exemplary embodiments are not limited thereto.
The grayscale voltage generator 700 according to an exemplary embodiment divides a driving voltage AVDD into a plurality of data voltages based on gray levels of the display data signals and provides the data voltages to the data driver 500. The grayscale voltage generator 700 may include a plurality of resistors (not shown) connected in electrical series with each other between a node, to which the driving voltage AVDD is applied, and a ground source. Thus, the grayscale voltage generator 700 divides a level of the driving voltage AVDD to generate a plurality of grayscale voltages. An internal circuit of the grayscale voltage generator 700 is not limited to the above mentioned example, and may be implemented in various ways in alternative exemplary embodiments. In an exemplary embodiment, the grayscale voltage generator 700 may divides a driving voltage AVDD into a plurality of gray reference voltages. And the gray reference voltages may be provided to the data driver 500. And the data driver 500 may divide the gray reference voltages into the data voltages corresponding to the display data signals.
Referring now to
The image signal processor 610 receives the original image signals R, G and B and outputs the display data signals DAT. As described above, the display data signals DAT include the normal data signals and the impulsive data signals. In addition, the image signal processor 610 changes the arrangement order of the original image signals R, G and B based on the order in which the first gate signals are sequentially and respectively transmitted to the first through (3n)th gate lines G1 through G3n, and thereby generates the normal data signals.
More specifically, the order in which the first gate signals are sequentially and respectively transmitted to the gate lines in the first group is different from the order in which the first gate signals are sequentially and respectively transmitted to the gate lines in the second group. Thus, to transmit the normal data signals to the pixels PX which are electrically connected to the first through (3n)th gate lines G1 through G3n, the normal data signals are sequentially and respectively transmitted to the pixels PX based on the order in which the first gate signals are sequentially and respectively transmitted to the first through (3n)th gate lines G1 through G3n. The image signal processor 610 and the normal data signals will be described in further detail below with reference to
In an exemplary embodiment, the display data signals DAT may be corrected by an additional process to substantially improve display quality.
The control signal generator 620 receives the external control signals (such as the data enable signal DE, the horizontal synchronization signal Hsync, the vertical synchronization signal Vsync and the main clock signal Mclk, for example) from an external source (not shown) and outputs the gate control signals CONT1 and the data control signals CONT2.
The gate control signals CONT1 control an operation of the gate driver 400. The gate control signals CONT1 may include, for example, a vertical start signal STV for starting the gate driver 400, a gate clock signal CPV for determining when to output the gate-on voltage Von and an output enable signal OE for determining a pulse width of the gate-on voltage Von.
The data control signals CONT2 control an operation of the data driver 500. The data control signals CONT2 may include, for example, a horizontal start signal STH for starting the data driver 500 and an output instruction signal TP for instructing output of the image data voltage.
The first gate signal and the second gate signal transmitted to the first through (3n)th gate lines G1 through G3n will now be described in further detail with reference to
Referring to
In
In an exemplary embodiment, the first group and the second group are adjacent to each other. More particularly, when a plurality of the gate lines are sequentially arranged on the display panel 33 and are divided into two or more groups, one of the groups is defined as a first group, and an adjacent successive group, relative to the first group, is therefore defined as a second group. Thus, the first group and the second group are defined in the above mentioned order. Conversely, when the first group, as defined above, is defined as the second group, and an adjacent and successive to the second group is therefore defined as the first group. Put another way, the groups may be defined according to an order of the second group and the first group.
The first through (3n)th gate lines G1 through G3n receive the first gate signal and the second gate signal such that the normal data voltages and the impulsive data voltages, respectively, are applied to the pixels PX which are electrically connected to the first through (3n)th gate lines G1 through G3n. More specifically, the pixels PX receive the normal data voltages in response to the first gate signals, and receive the impulsive data voltages in response to the second gate signals. As a result, the pixels PX display images, which respectively correspond to the normal and impulsive data voltages, on the display panel 300. In an exemplary embodiment, the first gate signals (indicated by reference character “N” in
The first gate signals are transmitted to the first through (3n)th gate lines G1 through G3n. In an exemplary embodiment, an order in which the first gate signals are sequentially and respectively transmitted to the first through (3n)th gate lines G1 through G3n is determined according to the group (e.g., the first group or the second group) to which the first through (3n)th gate lines G1 through G3n belong. For example, in an exemplary embodiment the first group includes ath through mth gate lines disposed sequentially on the display panel 300, and the first gate signals are sequentially transmitted to the ath through mth gate lines in this order. In addition, the second group includes nth through xth gate lines disposed sequentially on the display panel 300, and the first gate signals are sequentially be transmitted to the xth through nth gate lines.
Referring to the part A1 of
In an exemplary embodiment, the normal data voltages are charged in the pixels PX and are maintained until the second gate signals B are transmitted to the pixels PX after the first gate signals N are transmitted thereto. In an exemplary embodiment, a normal data output time is defined as a period of time which begins after a first gate signal N is transmitted to a given pixel PX and which ends before a second gate signal B is transmitted to the given pixel PX.
Still referring to
As described in greater detail above, the first gate signals N are sequentially transmitted to the first through nth gate lines G1 through Gn in part A1, and the second gate signals B are simultaneously applied to the first through nth gate lines G1 through Gn in the part A1. Thus, the normal data output time is gradually reduced along the first through nth gate lines G1 through Gn.
Specifically, referring to the part A1, the normal data output time of the second gate line G2 is (M−1)·H, which is shorter than the normal data output time (M·H) of the first gate line G1 by 1H, and the normal data output time of the third gate line G3 is ((M−2)·H), which is 1H shorter than the normal data output time ((M−1)·H) of the second gate line G2.
In addition, referring to the part B2, the normal data output time of the (n+1)th gate line Gn+1is [M−(n−1)]H, and the normal data output time of the (2n)th gate line G2n is M·H. Thus, the normal data output time (M·H) of the first gate line G1 in the part A1 is equal to normal data output time of the (2n)th gate line G2n in the part B2, and the normal data output time ([M−(n−1)]·H) of the nth gate line Gn in part A1 is equal to normal data output time of the (n+1)th gate line Gn+1 in the part B2.
Moreover, the normal data output times of the (2n+1)th through (3n)th gate lines G(2n+1) through G3n in the part C1 are substantially equal to the normal data output times of the first through nth gate lines G1 through Gn in part A1, respectively. Specifically, the normal data output time of the (2n+1)th gate line G(2n+1) is M·H, and the normal data output time of the (3n)th gate line G3n is [M−(n−1)]·H. Thus, the normal data output time of the (2n+1)th gate line G(2n+1) in the part C1 is equal to the normal data output time of the (2n)th gate line G2n in the part B2.
As a result, the order in which the first gate signals are sequentially provided to the gate lines varies according to whether the gate lines are included in the first group or the second group adjacent to the first group. Thus, the normal data output time is gradually reduced in an order from the first gate line G1 through the nth gate line Gn in part A1, and then gradually increases in an order from the (n+1)th gate line G(n+1) through the through the (2n)th gate line G2n in part B2, and is thereafter again reduced in an order from the (2n+1)th gate line G(2n+1) through the (3n)th gate line G3n in part C1.
As shown in
The normal data output time and the impulsive data output time of each gate line will now be described in further detail with reference to
As a result, referring to
As a period of time during which black data is transmitted to each gate line increases, a brightness of each gate line is reduced. When the brightness of the first gate line G1, having a relatively long normal data output time, is BH and when the brightness of the nth gate line Gn, having a short normal data output time relative to the first gate line G1, is BL, the brightness of the first through (3n)th gate lines G1 through G3n fluctuates between BH and BL, as shown in
Furthermore, when a number of the gate lines included in each group increases, gate lines in a boundary region between two adjacent groups have similar brightness levels in the LCD 10 according to an exemplary embodiment. Thus, the second gate signals need not be provided at different times, which results in a substantially reduction in a driving frequency required by the gate driver 400.
Images displayed on the display panel 300 according to an operation of the first through (3n)th gate lines G1 through G3n will now be described in further detail with reference to
In
Referring to
During a second stage Frame1-2 of the first frame, an image is not displayed in the part A, and images are sequentially displayed in the second direction b in the part B while images are sequentially displayed in the first direction a in the part C. Likewise, during a third frame Frame1-3 of the first frame, images are sequentially displayed in the direction “a” in part the A, and the impulsive image data is displayed in the part B while images are sequentially displayed in the direction “a” in the part C. During a first stage Frame 2-1 of a second frame, the first stage Frame 1-1 of the first frame is repeated. In an exemplary embodiment, displaying the impulsive image data includes displaying a black image, e.g., no image.
Thus, as shown in
Referring now to
According to exemplary embodiments of the present invention, the normal data voltages are transmitted to the pixels PX in response to the first gate signals N. Thus, the signal controller 600 changes a data arrangement order of the original image signals R, G and B based on the order in which the first gate signals N are sequentially transmitted corresponding gate lines and then generates the normal data signals.
The original image signals R, G and B according to an exemplary embodiment are arranged to correspond to sequentially arranged gate lines, e.g., the first through (3n)th gate lines G1 through G3n disposed on the display panel 300. Thus, the original signals R, G and B are arranged to correspond respectively to the first through (3n)th gate lines G1 through G3n, regardless of an arrangement of the parts A, B and C, into which the first through (3n)th gate lines G1 through G3n are divided. As shown in
Thus, the signal controller 600 according to an exemplary embodiment changes the data arrangement order of the original image signals R, G and B which corresponds to the arrangement order of the first through (3n)th gate lines G1 through G3n to the data arrangement order which corresponds to the order in which the first gate signals are sequentially and respectively transmitted to the first through (3n)th gate lines G1 through G3n. To this end, the arrangement order of the normal data signals of the display image signals DAT corresponds to the order in which the first gate signals are sequentially transmitted to the first through (3n)th gate lines G1 through G3n.
More specifically, as shown in
As shown in
According to exemplary embodiments of the present invention as described herein, an LCD includes advantages which include, but are not limited to, substantially improved display quality.
The present invention should not be construed as being limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concept of the present invention to those skilled in the art.
While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, the exemplary embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Moreover, it will be understood by those of ordinary skill in the art that various changes in form and detail may be made therein without departing from the spirit or scope of the present invention as defined by the following claims.
Number | Date | Country | Kind |
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10-2008-0115297 | Nov 2008 | KR | national |