KR100475115B1 - Liquid crystal display device - Google Patents

Abstract

The present invention provides a low-cost liquid crystal display device by changing the pixel configuration to express high resolution with a small number of pixels and by reducing the number of data driver ICs. Red and Green subpixels alternately arranged in one line region, and Blue alternately arranged in a second line region of the substrate to have a width twice the width of the red and green subpixels. White and white subpixels, and green and red subpixels alternately arranged in a third line region of the substrate to have the same width as the red and green subpixels, and on the substrate. The first to third line regions having the subpixels are repeatedly arranged.

Description

Liquid crystal display {LIQUID CRYSTAL DISPLAY DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device suitable for expressing high resolution in a small number of pixels by changing pixel configurations, and reducing manufacturing costs by reducing the number of data driver ICs.

As the information society develops, the demand for display devices is increasing in various forms, and in recent years, the LCD (Lipuid Crystal Display Device), PDP (Plasma Display Panel), ELD (Electro Luminescent Display), and VFD (Vacuum Fluorescent) Various flat panel display devices such as displays have been studied, and some of them are already used as display devices in various devices.

Among them, LCD is the most widely used as the substitute for CRT (Cathode Ray Tube) for mobile image display because of its excellent image quality, light weight, thinness, and low power consumption. In addition to the use of the present invention, a variety of applications such as a television, a computer monitor, and the like for receiving and displaying broadcast signals have been developed.

Such a liquid crystal display may be classified into a liquid crystal display panel displaying a video signal and a driving circuit applying a driving signal to the liquid crystal display panel from the outside.

Although not shown in the drawing, the liquid crystal display panel is a display device in which liquid crystal is injected between two transparent substrates (glass substrates) bonded to each other with a predetermined space, and a plurality of liquid crystal display panels arranged at regular intervals on one of the two transparent substrates. A plurality of gate lines, a plurality of data lines arranged at regular intervals in a direction perpendicular to the gate lines, a plurality of pixel electrodes formed in each pixel region in a matrix form defined by the gate lines and the data lines, A plurality of thin film transistors for applying the signal of the data line to each pixel electrode in accordance with the signal of the gate line is formed at a portion where the gate line and the data line cross each other. A color filter layer, a common electrode, and a black matrix layer are formed on the remaining substrates.

Therefore, when the turn-on signal is sequentially applied to the gate line, an image is displayed because a data signal is applied to the pixel electrode of the corresponding line.

In addition, a backlight is provided on the back surface of the two substrates thus bonded to provide a uniform light source. CCFL (Cold Cathode Fluorescent Lamp), which is used as a light source of the backlight, has an inverse relationship in brightness and lifetime in terms of its characteristics. That is, when driving at a high current to increase the brightness, the life is reduced, while to increase the life, it is difficult to achieve high luminance because it must be driven at a low current. In practice, however, in most cases, high brightness and long life are required simultaneously.

To meet these demands, while driving a screen with a certain brightness in a screen state of a general liquid crystal display device, when driving a screen where a high brightness is required, a high current is temporarily applied to a backlight lamp to temporarily It is applying technology to widen the active area.

In addition, in the case of the liquid crystal display device, the amount of current used varies depending on the image displayed on the screen. For example, in the normally white mode, in which liquid crystal molecules are rearranged in the direction of an electric field with the application of a voltage to block incident light, the panel consumes more power as the number of bright pixels on the screen increases. On the other hand, as the number of dark pixels increases, the power consumed by the panel tends to increase. By using this tendency, a method of controlling a current value of a lamp interlocked with the panel according to power consumed is mainly used.

The application of this technique requires the implementation of additional circuitry such as detecting the current consumed by the panel and modifying it to fit the variable range of the luminance control signal of the inverter driving the backlight.

Hereinafter, a general liquid crystal display having a driving circuit will be described with reference to the accompanying drawings.

1 is a block diagram of a driving circuit of a general liquid crystal display device.

As described above, the driving circuit of the liquid crystal display device includes a liquid crystal display panel 1 having a plurality of gate lines G and data lines D arranged in a direction perpendicular to each other and having a matrix-like pixel region, and the liquid crystal. The driving circuit unit 2 supplies a driving signal and a data signal to the display panel 1, and the backlight 8 provides a constant light source to the liquid crystal display panel 1.

The driving circuit unit 2 applies a gate driver pulse to a data driver 1b for inputting a data signal to each data line of the liquid crystal display panel 1 and a gate line of the liquid crystal display panel 1. Input the gate driver 1a, the display data R, G, and B inputted from the driving system of the liquid crystal display panel, and the control signals DTEN such as the vertical and horizontal synchronization signals Vsync and Hsync and the clock signal DCLK. A timing controller 3 which formats and outputs each display data, a clock, and a control signal at a timing suitable for each data driver 1b and the gate driver 1a of the liquid crystal display panel 1 to reproduce a screen; A power supply unit 4 for supplying a voltage required for the liquid crystal display panel 1 and each unit, and digital data input from the data driver 1b by receiving power from the power supply unit 4; A gamma reference voltage unit 5 for supplying a reference voltage required for conversion into analog data, a constant voltage V _DD and a gate used in the liquid crystal display panel 1 using the voltage output from the power supply unit 4. A DC / DC converter 6 for outputting a high voltage V _GH , a gate low voltage V _GL , a reference voltage V _ref , a common voltage Vcom, and an inverter for driving the backlight 8; 9) is configured.

The operation of the driving circuit of the conventional liquid crystal display device configured as described above is as follows.

That is, the timing controller 3 controls the display data R, G, and B inputted from the driving system PC of the liquid crystal display panel, the control signals such as the vertical and horizontal synchronization signals Vsync and Hsync, and the clock signal DCLK. Since the data driver 1b and the gate driver 1a of the liquid crystal display panel 1 provide each display data, a clock, and a control signal at a timing suitable for reproducing the screen, The gate driver 1a applies a gate driving pulse to each gate line of the liquid crystal display panel 1, and in synchronization therewith, the data driver 1b applies a data signal to each data line of the liquid crystal display panel 1. Display the input video signal.

At this time, the backlight 8 provides a backlight having a constant brightness regardless of the brightness of the input video signal.

Hereinafter, a pixel configuration of the liquid crystal display panel 1 according to the related art in the driving circuit of the liquid crystal display device having the above configuration will be described.

2 is a view showing a pixel configuration of a liquid crystal display panel according to the prior art, Figure 3 is a view showing a pixel configuration of a liquid crystal display panel according to another conventional technique, Figure 4 is a unit layout diagram of a conventional RGBW pixel to be.

First, FIG. 2 is a pentile (Pentile ^TM 1A) structure, which is a pixel layout of ClairVoyante Laboratories of the United States, in which red and green subpixels are alternately arranged in a line. Blue subpixels are arranged in a line adjacent thereto.

Using this structure of pixel layout enables high resolution with fewer pixels.

3 shows a general RGB stripe structure in which R subpixel lines, B subpixel lines, and G subpixel lines are repeatedly formed in this order.

Referring to the driving of the pixel line of the liquid crystal display device having the structure as shown in FIG. 2 and FIG. 3 as follows.

First, the driving of one pixel line in the pentile structure of FIG. 2 is performed by alternately driving a blue subpixel of a line in which red and green subpixels are alternately arranged, and a blue subpixel of an adjacent line thereof. In this case, the reason why the blue subpixels are alternately driven is that the resolution is reduced, and thus, even when driven alternately, it is recognized as one line.

Accordingly, in the pentile structure of FIG. 2 which drives the above driving, three data lines drive two pixel lines.

Next, driving of one pixel line in the RGB stripe structure of FIG. 3 is performed by driving red, green, and blue subpixels.

Thus, in the RGB stripe structure, three data lines drive one pixel line.

In Figs. 23 two structures are the same area one time, also cyclopenta one (Pentile ^TM 1A) of the second structure, while the four of horizontal lines, a possible implementation of vertical lines to six, RGB stripe structure of FIG 2 the horizontal lines Up to three vertical lines can be implemented.

In this case, since the number of pixels of the Pentile ^TM 1A structure is twice the same area, the resolution improvement is doubled assuming the same number of pixels.

Therefore, when implementing the same resolution, the number of gate driver ICs is the same and the number of data driver ICs can be reduced by half.

However, in order to apply the Pentile ^TM 1A structure to the liquid crystal display panel, a separate hardware for converting a signal generated in a conventional system to such a structure is required, which causes difficulty in driving.

In addition, in order to increase the luminance of the liquid crystal display device having the Pentile ^TM 1A structure, the backlight should be brightened. If the backlight is brightened as described above, power consumption is increased.

 FIG. 4 is a layout diagram of RGBW pixels in which white subpixels are added to RGB subpixels in order to realize CRT-like image quality in a liquid crystal display, and may increase peak luminance by adding white subpixels. FIG. .

However, in this case, when implementing the same resolution, there is a problem that the number of data driver ICs is increased by 4/3 times.

This structure is inconsistent with the recent trend toward lower prices of liquid crystal displays.

As described above, the liquid crystal display according to the related art has the following problems.

First, in order to increase the brightness of a pentile (Pentile ^TM 1A) liquid crystal display device, it is necessary to brighten the backlight, thereby increasing the power consumption.

Second, the RGB stripe structure has a problem in that the number of data driver ICs is increased compared to the pentile structure, and the resolution decreases when driving the same number of data driver ICs.

Third, in the RGBW pixel structure, the number of data driver ICs is increased by 4/3 compared to the RGB stripe structure, making it difficult to manufacture a low-cost liquid crystal display device.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a low-cost liquid crystal display device by changing the pixel configuration to represent a high resolution with a small number of pixels, and by reducing the number of data driver ICs. have.

According to an exemplary embodiment of the present invention, a liquid crystal display device includes red and green subpixels alternately disposed in a first line region of a substrate, and twice the width of the red and green subpixels. Blue and white subpixels alternately arranged in the second line region of the substrate to have a width, and alternately arranged in the third line region of the substrate so as to have the same width as the red and green subpixels. Green and red subpixels and the first to third line regions having the subpixels on the substrate are repeatedly arranged.

The blue and white subpixels and the red and green subpixels have the same length.

The blue and white subpixels are adjacent to each other in the length direction of each of the red and green subpixels of the first and third line regions, respectively.

The area ratios of the red, green, blue, and white subpixels, which are physical repeating units of the subpixels, may be 1: 1: 1: 1.

The subpixels are color filter layers disposed on the upper substrate of the liquid crystal display panel.

In the lower substrate of the liquid crystal display panel, a gate line and a data line cross each other to correspond to a boundary area of each subpixel of the upper substrate, and a thin film transistor T is formed at the crossing portion.

A pixel area is defined by crossing the gate line and the data line, and the pixel area is formed to correspond to the width and length of each subpixel of the upper substrate.

The present invention is characterized by changing the pixel layout of the liquid crystal display panel so as to express high resolution and reduce the number of data driver ICs.

Hereinafter, a liquid crystal display according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.

5 is a driving circuit diagram of a liquid crystal display device having a liquid crystal display panel for applying the present invention, FIG. 6 is a view showing a pixel configuration of a liquid crystal display panel according to the present invention, and FIG. The corresponding unit circuit diagram is shown.

In the driving circuit of the liquid crystal display device having the liquid crystal display panel according to the present invention, as shown in FIG. 5, a plurality of gate lines G and data lines D are arranged in a cross-section to define a plurality of pixel regions. And a driving circuit unit 52 for supplying a driving signal and a data signal to the liquid crystal display panel 51, and a backlight 58 for providing a constant light source to the liquid crystal display panel 51.

The driving circuit unit 52 applies a gate driver pulse to the data driver 51b for inputting a data signal to each data line of the liquid crystal display panel 51 and the gate lines of the liquid crystal display panel 51. the gate driver (51a), and a display data inputted from the drive system of the liquid crystal display panel (R _i, G _i, B _i) and the vertical and horizontal sync signals (Vsync, Hsync) and clock signal (DCLK) such as a control signal (DTEN ) the input received, displays the inputted display data (R _i, G _i, B _i) an operation to display output data (R _o, G _o, B _o, W _o) computing unit (60) for outputting, and a liquid crystal Format each display output data (R _o , G _o , B _o , W _o ) and clock and control signals at a timing suitable for each data driver 51b and gate driver 51a of the panel 51 to reproduce the screen. And a timing controller 53 and the liquid crystal display panel 51 to output the same. A gamma supplying power supply unit 54 for supplying a necessary voltage to each unit, and a reference voltage required for converting digital data input from the data driver 51b into analog data by receiving power from the power supply unit 54; The constant voltage V _DD , the gate high voltage V _GH , the gate low voltage V _GL used in the liquid crystal display panel 51 by using the reference voltage unit 55 and the voltage output from the power supply unit 54, And a DC / DC converter 56 for outputting a reference voltage V _ref , a common voltage Vcom, and the like, and an inverter 59 for driving the backlight 58.

The operation of the driving circuit of the liquid crystal display device configured as described above is as follows.

That is, the timing controller 53, the display data inputted from the drive system (PC) of the liquid crystal display panel (R _i, G _i, B _i) and the vertical and horizontal sync signals (Vsync, Hsync) and clock signal (DCLK), etc. In response to the control signal DTEN, the data driver 51b and the gate driver 51a of the liquid crystal display panel 51 display the display data, the clock, and the control signal at a timing suitable for reproducing the screen. Since the gate driver 51a applies a gate driving pulse to each gate line of the liquid crystal display panel 51, the data driver 51b is applied to each data line of the liquid crystal display panel 51 in synchronization with the gate driver 51a. The data signal is input to display the input video signal.

In this case, the backlight 58 provides a backlight having a constant brightness regardless of the brightness of the input image signal.

The present invention is characterized in that the driving circuit configured as described above is configured by changing the pixel layout of the liquid crystal display panel.

That is, as shown in FIG. 6, red and green subpixels are alternately arranged in the first line region, and blue and white subpixels are alternately arranged in the second line region. Green and Red subpixels are alternately placed in the third line region.

Subpixels of the first, second, and third line regions are repeatedly formed.

At this time, the red and green subpixels of the first line region and the green and red subpixels of the third line region have the same width and the blue of the second line region. ) And white subpixels are twice as wide as the first and third line regions.

The blue and white subpixels and the red and green subpixels have the same length, and the blue and white subpixels have first and third lines, respectively. Each red and green subpixel of the region is adjacent to each other by 1/2 in the length direction.

The pixel layout shown in FIG. 6 is a layout of a color filter layer disposed on an upper substrate of the liquid crystal display panel.

An area 'A' of FIG. 6 is a physical repeating unit of a pixel, and an area ratio of R, G, B, and W is 1: 1: 1: 1.

This configuration has the advantage that the white balance problem does not occur.

As shown in FIG. 7, a circuit diagram of a lower substrate corresponding to the pixel layout includes a plurality of gate lines G / L1 and G / L2 formed with irregularities on a lower substrate corresponding to each pixel region of the upper substrate; A thin film that crosses the gate line to form a switching region by crossing a plurality of data lines D / L1, D / L2, and D / L3 and crossing the gate line and the data line. There is a liquid crystal capacitor Clc between the transistor T, the drain electrode of the thin film transistor T, and the ground voltage, and a storage capacitor Cst between the drain electrode of the thin film transistor T and the gate line of the previous stage. .

The circuit configuration described above shows a circuit configuration that is physically repeated and corresponds to the area 'A' of FIG. 6.

In addition, the circuit diagram shown in FIG. 7 illustrates a structure formed on the lower substrate of the liquid crystal display panel, and the gate line and the data line cross each other to correspond to the boundary region of each subpixel formed on the upper substrate of FIG. The thin film transistor T is formed in the portion.

In this case, a pixel region is defined by crossing the gate line and the data line, and the pixel region is configured to correspond to the width and length of each subpixel of the upper substrate.

The driving of one pixel line of the liquid crystal display having the above structure simultaneously operates the red and green subpixels of the first line region and the blue and white subpixels of the second line region. Is done.

Subsequently, another driving of one pixel line is performed by simultaneously operating the blue and white subpixels of the two line region and the green and red subpixels of the third line region.

In the conventional RGB stripe structure, one pixel is formed by subpixels of R, G, and B. Three data lines are required to drive one pixel line, and six data are required to implement two pixel lines. I need a line.

In contrast, in the present invention, the first and second data lines D / L1 and D / L2 are used to drive one pixel line, and then the second and third data lines D / L2 and D / L3 are used. Since it is used to drive another pixel line, three data lines are required to implement two pixel lines.

As a result, the number of data driver ICs can be reduced by one half compared with the conventional RGB stripe structure.

In addition, it is possible to display a high resolution image with a smaller number of pixels than a conventional RGB stripe structure.

The white subpixel data may be generated based on R, G, and B input data.

There are a method using a harmonic mean, a method using a minimum luminance, and a method using a luminance proportional value.

First, the white subpixel data based on the harmonic mean is

or Obtained using Equation 1

The distinctive feature of this method is that it preserves color among brightness, saturation and color.

Next, the white subpixel data at the minimum luminance is

or It is obtained using Equation 2 as follows.

The main feature of this method is that it maintains color in brightness, saturation and color.

Next, the white sub pixel data using the luminance proportionality is

Wow,

Obtained by using Equation 3, Equation 4, and the like.

In order to apply Equations 3 and 4, R, G, and B values are changed to be R _i : G _i : B _i = R _o + W _sub : G _o + W _sub : B _o + W _sub .

The characteristic of this method is that color reproduction is most faithful with brightness, saturation, saturation, and color retention.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the above embodiments, but should be defined by the claims.

The liquid crystal display of the present invention as described above has the following effects.

First, since the number of data driver ICs can be reduced by half compared to the conventional RGB stripe structure, a low-cost liquid crystal display device can be manufactured.

Second, a high resolution image can be displayed with a smaller number of pixels than the conventional RGB stripe structure.

Third, by constructing a 4-pixel structure of R, G, B, and W, and by setting the area ratio of the physical repeating unit of each pixel to 1: 1: 1: 1, it is possible to prevent a white balance problem from occurring. have.

Fourth, the luminance is higher than that of a liquid crystal display having an RGB pixel structure by having white subpixels. Therefore, even if the backlight is brightened to increase the brightness can reduce the power consumption compared to the prior art.

1 is a configuration diagram of a driving circuit of a general liquid crystal display device

2 is a diagram illustrating a pixel configuration of a liquid crystal display panel according to the related art.

3 is a diagram illustrating a pixel configuration of a liquid crystal display panel according to another conventional technology.

4 is a unit layout diagram of a conventional RGBW pixel.

5 is a configuration diagram of a driving circuit of a liquid crystal display according to an exemplary embodiment of the present invention.

6 is a diagram illustrating a pixel configuration of a liquid crystal display panel according to the present invention.

7 is a unit circuit diagram corresponding to a pixel configuration of the present invention.

Explanation of symbols on the main parts of the drawings

51 liquid crystal display panel 51a gate driver

51b: data driver 52: driver circuit portion

53: timing controller 54: power supply

55: gamma reference voltage section 56: DC / DC converter

57: LCM drive system 58: back light

59: inverter 60: calculator

Claims (7)

Red and Green subpixels alternately disposed in the first line region of the substrate, Blue and white subpixels having a width twice the width of the red and green subpixels and alternately disposed in the second line region of the substrate; Green and red subpixels alternately arranged in the third line region of the substrate to have the same width as the red and green subpixels; And the first to third line regions including the subpixels are repeatedly disposed on the substrate. The method of claim 1, And the blue and white subpixels and the red and green subpixels have the same length. The method of claim 1, The blue and white subpixels are adjacent to each other by 1/2 in the length direction of each of the red and green subpixels of the first and third line regions, respectively. Display. The method of claim 1, The area ratio of the red, green, blue, and white subpixels, which are physical repeating units of the subpixels, is arranged to be 1: 1: 1: 1. . The method of claim 1, And the subpixels are color filter layers disposed on an upper substrate of the liquid crystal display panel. The method of claim 5, wherein The lower substrate of the liquid crystal display panel may have a gate line and a data line intersecting to correspond to a boundary area of each subpixel of the upper substrate, and a thin film transistor T is formed at the crossing portion. Display. The method of claim 6, And a gate area and a data line crossing each other to define a pixel area, wherein the pixel area corresponds to a width and a length of each subpixel of the upper substrate.