KR20070064061A - Display device - Google Patents

Abstract

A display apparatus is provided to prevent a phenomenon that different hue is represented at the same gradation level, by disposing two data driving units at different sides and alternately arranging the data lines connected to the data driving units. A plurality of pixels is arranged in a matrix form. Data lines(D1~Dm) are connected to the pixels and transfer data voltages. A plurality of data driving units(500a,500b) applies data voltages to the data lines. The pixels and data lines are formed in a display substrate(300). The data driving units are disposed at different sides of the display substrate, and the data lines are alternately connected to the data driving units.

Description

Display device {DISPLAY DEVICE}

With reference to the accompanying drawings will be described in detail the embodiments of the present invention to make the present invention clear.

1 is a block diagram of a liquid crystal display according to an exemplary embodiment of the present invention.

2 is an equivalent circuit diagram of one pixel of a liquid crystal display according to an exemplary embodiment of the present invention.

3 is a schematic diagram of a liquid crystal display according to an exemplary embodiment of the present invention.

4 is a schematic view of a liquid crystal display device according to the prior art.

<Description of Drawing>

3: liquid crystal layer 100: lower display panel

191: pixel electrode 200: upper display panel

230: color filter 270: common electrode

300: liquid crystal panel assembly 400: gate driver

500a and 500b: data driver 600: signal controller

800: gray voltage generator

R, G, B: Input image data DE: Data enable signal

MCLK: Main Clock Hsync: Horizontal Sync Signal

Vsync: Vertical Sync Signal CONT1: Gate Control Signal

CONT2: data control signal DAT: digital video signal

Clc: Liquid Crystal Capacitor Cst: Keeping Capacitor

Q: switching element VGa, VGb: gradation voltage

The present invention relates to a display device.

Recently, organic light emitting diode display (OLED), plasma display panel (PDP), liquid crystal display (liquid crystal display) in place of heavy and large cathode ray tube (CRT) Flat panel displays such as LCDs are being actively developed.

The PDP is a device for displaying characters or images using plasma generated by gas discharge, and the organic light emitting diode display displays characters or images by using electroluminescence of specific organic materials or polymers. The liquid crystal display device applies an electric field to a liquid crystal layer interposed between two display panels, and adjusts the intensity of the electric field to adjust a transmittance of light passing through the liquid crystal layer to obtain a desired image.

Among such flat panel displays, for example, a liquid crystal display and an organic light emitting display may turn on / off a switching element of a pixel by emitting a gate signal to a pixel including a switching element, a display panel having a display signal line, and a gate line among the display signal lines. The off-key is a gate driver, a gray voltage generator for generating a plurality of gray voltages, a data driver for applying a data voltage to a data line among display signal lines by selecting a voltage corresponding to image data among the gray voltages, and It includes a signal control unit for controlling.

Meanwhile, among such display devices, small and medium sized display devices such as mobile phones and PDAs are gradually increasing in size and resolution, and two or more data driving integrated circuits, which were previously displayed using one data driving integrated circuit, should be used.

In this case, when the outputs of the data driving integrated circuits are different, so-called color separation phenomenon in which colors are different from each other even though the same gray levels are expressed.

Accordingly, an object of the present invention is to provide a display device capable of eliminating such color separation.

According to an exemplary embodiment of the present invention, a display device includes a plurality of pixels arranged in a matrix form, a data line connected to the pixel and transferring a data voltage, and a data voltage applied to the data line. A plurality of data driving units, and a display panel unit in which the pixel and the data line are provided, wherein the plurality of data driving units are disposed on different sides of the display panel unit, and the data lines are alternately connected to the data driving unit. have.

In this case, the plurality of data drivers may include first and second drivers, the first driver may be disposed above the display panel, and the second driver may be disposed below the display panel.

The first driver may be connected to odd-numbered data lines of the data lines, and the second driver may be connected to even-numbered data lines.

DETAILED DESCRIPTION Embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like parts are designated by like reference numerals throughout the specification. When a portion of a layer, film, region, plate, etc. is said to be "on top" of another part, this includes not only when the other part is "right on" but also another part in the middle. On the contrary, when a part is "just above" another part, there is no other part in the middle.

First, a display device according to an exemplary embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2, and a liquid crystal display device will be described as an example.

1 is a block diagram of a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 2 is an equivalent circuit diagram of one pixel of the liquid crystal display according to an exemplary embodiment of the present invention. 3 is a schematic diagram of a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 4 is a schematic diagram of a liquid crystal display according to the related art.

As shown in FIG. 1, a liquid crystal display according to an exemplary embodiment of the present invention includes a liquid crystal panel assembly 300, a gate driver 400 and a data driver 500a and 500b connected thereto, The gray voltage generator 800 connected to the data drivers 500a and 500b and a signal controller 600 for controlling the gray voltage generator 800 are included.

The liquid crystal panel assembly 300 may include a plurality of signal lines G ₁ -G _n , D ₁ -D _m and a plurality of pixels PX connected to the plurality of signal lines G ₁ -G _n , D ₁ -D _m , and arranged in a substantially matrix form. Include. On the other hand, in the structure shown in FIG. 2, the liquid crystal panel assembly 300 includes lower and upper panels 100 and 200 facing each other and a liquid crystal layer 3 interposed therebetween.

The signal lines G ₁ -G _n and D ₁ -D _m are a plurality of gate lines G ₁ -G _n for transmitting a gate signal (also called a “scan signal”) and a plurality of data lines for transmitting a data signal ( D ₁ -D _m ). The gate lines G ₁ -G _n extend substantially in the row direction and are substantially parallel to each other, and the data lines D ₁ -D _m extend substantially in the column direction and are substantially parallel to each other.

Each pixel PX, for example, the pixel PX connected to the i-th (i = 1, 2,, n) gate line G _i and the j-th (j = 1, 2,, m) data line Dj. ) Includes a switching element Q connected to the signal line G _i D _j , a liquid crystal capacitor Clc, and a storage capacitor Cst connected thereto. Holding capacitor Cst can be omitted as needed.

The switching element Q is a three-terminal element of a thin film transistor or the like provided in the lower panel 100, the control terminal of which is connected to the gate line G _i , and the input terminal of which is connected to the data line D _j . The output terminal is connected to the liquid crystal capacitor Clc and the storage capacitor Cst.

The liquid crystal capacitor Clc has two terminals, the pixel electrode 191 of the lower panel 100 and the common electrode 270 of the upper panel 200, and the liquid crystal layer 3 between the two electrodes 191 and 270 is a dielectric material. Function as. The pixel electrode 191 is connected to the switching element Q, and the common electrode 270 is formed on the front surface of the upper panel 200 and receives the common voltage Vcom. Unlike in FIG. 2, the common electrode 270 may be provided in the lower panel 100. In this case, at least one of the two electrodes 191 and 270 may be formed in a linear or bar shape.

The storage capacitor Cst, which serves as an auxiliary part of the liquid crystal capacitor Clc, is formed by overlapping a separate signal line (not shown) and the pixel electrode 191 provided on the lower panel 100 with an insulator interposed therebetween. A predetermined voltage such as the common voltage Vcom is applied to the separate signal line. However, the storage capacitor Cst may be formed such that the pixel electrode 191 overlaps the front gate line directly above the insulator.

On the other hand, in order to implement color display, each pixel PX uniquely displays one of the primary colors (spatial division) or each pixel PX alternately displays the primary colors over time (time division). The desired color is recognized by the spatial and temporal sum of these primary colors. Examples of the primary colors include three primary colors such as red, green, and blue. 2 illustrates that each pixel PX includes a color filter 230 representing one of the primary colors in an area of the upper panel 200 corresponding to the pixel electrode 191 as an example of spatial division. . Unlike FIG. 2, the color filter 230 may be formed above or below the pixel electrode 191 of the lower panel 100.

At least one polarizer (not shown) for polarizing light is attached to an outer surface of the liquid crystal panel assembly 300.

Referring back to FIG. 1, the gray voltage generator 800 generates two sets of gray voltage sets (or reference gray voltage sets) VGa and VGb related to the transmittance of the pixel PX. One of the two sets has a positive value for the common voltage Vcom and the other set has a negative value.

A gate driver 400, a gate line (G ₁ -G _n) and is connected to the gate turn-on voltage (Von), and a gate signal consisting of a combination of a gate-off voltage (Voff), a gate line (G ₁ of the liquid crystal panel assembly 300 -G _n ).

The data drivers 500a and 500b are disposed in the peripheral area PA of the liquid crystal panel assembly 300 and connected to the data lines D ₁ -D _m . The liquid crystal panel assembly 300 is illustrated in FIG. 3. The data driver 500a positioned at the upper side of the data driver 500a is connected to the odd-numbered data lines D ₁ , D ₃ ,..., D _m-1 , and the data driver 500b positioned below the liquid crystal panel assembly 300 is provided. It is connected to even-numbered data lines D ₂ , D ₄ , .., D _m .

As such, when the data drivers 500a and 500b are disposed above and below the liquid crystal panel assembly 300, color separation may be solved. That is, even if the outputs of the two data drivers 500a and 500b are different, the data lines D _{1 to} D _m connected to the data drivers 500a and 500b are alternately arranged, thereby representing an average value of the outputs of the two data drivers 500a and 500b. For this reason, a uniform screen is displayed on the whole screen.

In contrast, the data drivers 500a and 500b of the conventional liquid crystal display are positioned on only one side, and a part of the data lines D ₁ -D _k are stored in the data driver 500a and the remaining D _{k + 1} -D _m It is connected to the data driver 500b. As a result, when the outputs of the data drivers 500a and 500b differ, the color difference occurs immediately after the color difference, in which the display area DA is divided into two areas A and B. FIG. However, according to the present invention, since the data lines D ₁ -D _m connected to the two data drivers 500a and 500b are alternately positioned, this color separation can be prevented.

Each data driver 500a and 500b selects the gray voltages VGa and VGb from the gray voltage generator 800 and applies them to the data lines D ₁ -D _m as data signals. However, when the gray voltage generator 800 provides only a predetermined number of reference gray voltages instead of providing all of the voltages for all grays, the data driver 500 divides the reference gray voltages to divide the gray voltages for all grays. Generate and select the data signal from it.

The signal controller 600 controls the gate driver 400, the data driver 500, and the like.

Each of the driving devices 400, 500a, 500b, 600, and 800 may be mounted directly on the liquid crystal panel assembly 300 in the form of at least one integrated circuit chip, or may be a flexible printed circuit film (not shown). It may be mounted on the liquid crystal panel assembly 300 in the form of a tape carrier package (TCP), or mounted on a separate printed circuit board (not shown). Alternatively, these driving devices 400, 500a, 500b, 600, and 800 are connected to the liquid crystal panel assembly 300 together with the signal lines G ₁ -G _n , D ₁ -D _m and the thin film transistor switching element Q. It may be integrated. In addition, the driving devices 400, 500a, 500b, 600, and 800 may be integrated into a single chip, in which case at least one of them or at least one circuit element constituting them may be outside the single chip.

Next, the operation of the liquid crystal display will be described in detail.

The signal controller 600 receives input image signals R, G, and B and an input control signal for controlling the display thereof from an external graphic controller (not shown). Examples of the input control signal include a vertical sync signal Vsync, a horizontal sync signal Hsync, a main clock MCLK, and a data enable signal DE.

The signal controller 600 properly processes the input image signals R, G, and B according to operating conditions of the liquid crystal panel assembly 300 based on the input image signals R, G, and B and the input control signal, and controls the gate. After generating the signal CONT1 and the data control signals CONT2a and CONT2b, the gate control signal CONT1 is sent to the gate driver 400, and the data control signals CONT2a and CONT2b and the processed image signals DATa and DATb. ) Are exported to the data drivers 500a and 500b, respectively.

The gate control signal CONT1 includes a scan start signal STV indicating a scan start and at least one clock signal controlling an output period of the gate-on voltage Von. The gate control signal CONT1 may also further include an output enable signal OE that defines the duration of the gate-on voltage Von.

The data control signals CONT2a and CONT2b apply a data signal to the horizontal synchronization start signal STH and the data lines D ₁ -D _m indicating the start of image data transfer for one row (bundling) of the pixels PX. Includes a load signal LOAD and a data clock signal HCLK. The data control signal CONT2 is also an inverted signal that inverts the voltage polarity of the data signal relative to the common voltage Vcom (hereinafter referred to as " polarity of the data signal " by reducing the " voltage polarity of the data signal for the common voltage &quot;) RVS) may be further included.

According to the data control signal CONT2 from the signal controller 600, the data driver 500a and 500b receive the digital image signal DAT for the pixel PX in one row (bundling), and each digital image signal. By selecting the gray scale voltage corresponding to (DATa, DATb), the digital image signals DATa and DATb are converted into analog data signals and then applied to the corresponding data lines D ₁ -D _m .

The gate driver 400 applies the gate-on voltage Von to the gate lines G ₁ -G _n in response to the gate control signal CONT1 from the signal controller 600, thereby applying the gate lines G ₁ -G _n . Turn on the switching element (Q) connected to. Then, the data signal applied to the data lines D ₁ -D _m is applied to the pixel PX through the turned-on switching element Q.

The difference between the voltage of the data signal applied to the pixel PX and the common voltage Vcom is shown as the charging voltage of the liquid crystal capacitor Clc, that is, the pixel voltage. The arrangement of the liquid crystal molecules varies depending on the magnitude of the pixel voltage, thereby changing the polarization of light passing through the liquid crystal layer 3. The change in polarization is represented by a change in transmittance of light by a polarizer attached to the display panel assembly 300.

This process is repeated in units of one horizontal period (also referred to as "1H" and equal to one period of the horizontal sync signal Hsync and the data enable signal DE), thereby all the gate lines G ₁ -G _n. ), The gate-on voltage Von is sequentially applied to the data signal to all the pixels PX, thereby displaying an image of one frame.

When one frame ends, the state of the inversion signal RVS applied to the data driver 500 is controlled so that the next frame starts and the polarity of the data signal applied to each pixel PX is opposite to the polarity of the previous frame. "Invert frame"). In this case, the polarity of the data signal flowing through one data line is changed (eg, row inversion and point inversion) or the polarity of the data signal applied to one pixel row is different depending on the characteristics of the inversion signal RVS within one frame. (E.g. column inversion, point inversion).

As described above, the two data drivers 500a and 500b are disposed on different sides and the data lines D _{1 to} D _m connected thereto are alternately disposed to prevent color separation.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (3)

A plurality of pixels arranged in a matrix form, A data line connected to the pixel and transferring a data voltage; A plurality of data drivers for applying a data voltage to the data line, and A display panel provided with the pixel and the data line Including, The plurality of data driving units are disposed on different sides of the display panel unit. The data lines are alternately connected to the data driver. Display device. In claim 1, The plurality of data drivers include first and second drivers, The first driver is disposed above the display panel, and the second driver is disposed below the display panel. Display device. In claim 2, And the first driver is connected to odd-numbered data lines of the data lines, and the second driver is connected to even-numbered data lines.

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