KR20080003559A - Liquid crystal display - Google Patents

Abstract

An LCD is provided to remove a converting circuit by integrally forming a graphic control unit for generating an image signal and a liquid crystal driving unit for controlling an LCD(liquid crystal display) panel and to prevent the quality of LCD from being deteriorated. A display area and a mounting area are defined in an LCD panel. A data driving unit(110) and a gate driving unit(120) are formed in the mounting area. A graphic control unit(210) and a liquid crystal driving unit(220) are integrally formed in a driving circuit board. The graphic control unit outputs an image signal. The liquid crystal driving unit receives the image signal and converts the image signal into a control signal suitable for the driving characteristic of the LCD panel to output the converted control signal. A flexible printed circuit transmits the control signal output from the driving circuit board to the LCD panel.

Description

Liquid crystal display

1 is a perspective view illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

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

3 is a circuit diagram illustrating a configuration circuit of a gray voltage generator of a liquid crystal display according to an exemplary embodiment of the present invention.

4 is a block diagram illustrating a connection relationship between a graphic controller and a timing controller in a liquid crystal display according to a comparative example and an application example of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: liquid crystal display panel 110: data driver

120: gate driver 210: graphic controller

221: timing control unit 222: power conversion unit

223: gray voltage generator 224: reference voltage generator

300: flexible printed circuit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display, and more particularly, to a liquid crystal display including an integrated graphic control unit for generating an image signal and a liquid crystal driving unit for controlling the liquid crystal display panel.

Liquid crystal display is a display device that realizes an image by controlling the amount of light incident from a light source using the optical anisotropy of liquid crystal molecules and the polarization characteristics of a polarizing plate. The liquid crystal display can realize light weight, high resolution, and large screen. In addition, the power consumption is small, the application range is expanding rapidly in recent years.

Such a liquid crystal display implements an image that can be recognized by a user by receiving an image signal from an external graphic controller.

In general, the liquid crystal display includes a liquid crystal display panel for implementing an image, a liquid crystal driver for controlling the liquid crystal display panel, and the graphic controller includes a graphic processor, a RAMDAC, and a memory. The graphic controller and the liquid crystal driver include a LVDS transmitter and an LVDS receiver that satisfy a Low Voltage Differential Signaling (LVDS) standard, which is a transmission protocol. The LVDS is a protocol for transmitting signals at high speed using copper wire, and has a merit of reducing power consumption by using a low voltage of 3.3 V or 1.5 V instead of 5 V, which is a standard voltage. This is the technique used.

The graphic processor generates and outputs a digital signal including a synchronization signal and an image signal, and the output digital signal is stored in a memory. The RAMDAC encodes an image signal stored in a memory so as to be suitable for color and resolution, and converts a digital signal into an analog signal and outputs the analog signal. The output analog signal is transmitted to the liquid crystal driver through the LVDS transmitter and the LVDS receiver, and the liquid crystal driver restores the digital signal back to the digital signal and generates and outputs various control signals corresponding thereto to control the liquid crystal display panel. In this case, digital-to-analog conversion is performed by the graphic controller because the CRT monitor which is generally used operates as an analog signal, and analog-to-digital conversion is performed by the liquid crystal driver because the liquid crystal display operates as a digital signal. .

However, the liquid crystal display according to the related art needs to convert an analog signal output from the graphic controller into a digital signal suitable for the operation characteristics of the liquid crystal display, and thus requires a separate converting circuit, and the original signal may be distorted during the converting process. There was concern. In addition, a transmission protocol for transmitting an analog signal output from the graphic controller, that is, a transceiver that satisfies the LVDS standard is required. In addition, it is difficult to test compatibility and compatibility with the graphic control unit in advance. For this reason, the liquid crystal display according to the related art has a problem of low display quality and high manufacturing cost.

Accordingly, the present invention integrates the graphic control unit for generating an image signal and the liquid crystal drive unit for controlling the liquid crystal display panel, thereby eliminating the converting circuit, thereby preventing display quality deterioration and reducing the manufacturing cost. It is an object of the present invention to provide a liquid crystal display device having a.

In the liquid crystal display according to the present invention for achieving the above object, a display region and a mounting region are defined, the liquid crystal display panel formed with a data driver and a gate driver in the mounting region, a graphic controller for outputting an image signal and the And a driving circuit board integrally formed with a liquid crystal driver for receiving an image signal and converting the image signal into a control signal suitable for driving characteristics of the liquid crystal display panel.

Preferably, the data driver and the gate driver are driving chips mounted directly on the liquid crystal display panel using a COG method. Alternatively, the data driver and the gate driver may be driving chips formed together when the liquid crystal display panel is manufactured.

The liquid crystal display device may further include a flexible printed circuit which transmits a control signal output from the driving circuit board to the liquid crystal display panel.

The flexible printed circuit is preferably formed of a multilayer wiring.

The liquid crystal driver may apply a control signal to the data driver and the gate driver in a current mode interface cascade COG (CICC) method for transmitting data to another chip through an adjacent driver chip.

Hereinafter, with reference to the accompanying drawings will be described embodiments of the present invention;

However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the embodiments make the disclosure of the present invention complete and the scope of the invention to those skilled in the art. It is provided to inform you completely. Like reference numerals in the drawings refer to like elements.

1 is a perspective view illustrating a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 2 is a block diagram illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

1 and 2, the liquid crystal display includes a liquid crystal display panel 100 in which a display area A1 and a mounting area A2 are defined, and various control signals for driving the liquid crystal display panel 100. And a flexible printed circuit 300a and 300b for transmitting a control signal output from the driving circuit board 200 to the liquid crystal display panel 100. It includes.

The display area A1 includes a plurality of unit pixels formed in a lattice structure. The unit pixel is defined by an intersection area of a plurality of data lines D1 to Dm and a plurality of gate lines G1 to Gn formed vertically and horizontally, and includes a switching element, a liquid crystal capacitor Clc, and a storage capacitor Cst connected thereto. It includes. In addition, the unit pixel may include red (R), green (G), and blue (B) pixels, and display a color image through a combination thereof.

The switching element is formed of amorphous silicon, polycrystalline silicon, or the like as a channel layer, and uses a thin film transistor (TFT) including a gate electrode, a source electrode, and a drain electrode. Is effective. In this case, the source electrode is connected to the data lines D1 to Dm, the gate electrode is connected to the gate lines G1 to Gn, and the drain electrode is connected to the pixel electrode, the liquid crystal capacitor Clc, and the storage capacitor Cst. Connected.

The liquid crystal capacitor Clc includes a pixel electrode (not shown), a common electrode (not shown), and a liquid crystal layer (not shown) filled therebetween. The electric field formed between the pixel electrode and the common electrode is changed according to the input gray voltage to change the molecular arrangement of the liquid crystal molecules, thereby changing the transmittance of the light incident from the lower backlight (not shown), thereby realizing an image.

The storage capacitor Cst may be configured by overlapping data lines D1 to Dm or gate lines G1 to Gn with a portion of the pixel electrode (not shown). The gray voltage transferred through the data lines D1 to Dm and the source electrode is charged in the storage capacitor Cst and maintained for a predetermined frame, of course, the storage capacitor Cst may be omitted as necessary. .

The data driver 110 and the gate driver 120 for driving the unit pixel are provided in the mounting area A2. The data driver 110 is connected to each data line D1 to Dm to apply a data control signal, and the gate driver 120 is connected to each gate line G1 to Gn to apply a gate control signal. The data driver 110 and the gate driver 120 are formed on a driving chip mounted directly on the liquid crystal display panel 100 using a chip on glass (COG) method or a driving chip formed when the liquid crystal display panel 100 is manufactured. It is preferable to use.

The driving circuit board 200 is integrally formed including the graphic controller 210 and the liquid crystal driver 220, and the liquid crystal driver 220 includes a timing controller 221, a power converter 222, and a gray voltage generator. 223 and a reference voltage generator 224.

The graphic controller 210 receives an image signal and generates and outputs a digital signal including an R, G, and B image signal and a synchronization signal. The graphic controller 210 may include a graphic processor and a memory, and a digital-to-analog converter (AD converter) for outputting an analog signal may be omitted.

The timing controller 221 is a data enable signal which is an R, G, B image signal, a horizontal synchronization signal (Hsync), a vertical synchronization signal (Vsync), a main clock signal (MCLK), and an output signal input from the graphic controller 210. R, G, and B grayscale data and various control signals are generated and output in response to a synchronization signal such as (DE).

At this time, the control signal output to the data driver 110 includes a horizontal synchronization start signal (Hstart) corresponding to the horizontal synchronization signal and a load signal (LOAD) for commanding the application of the signal of the R, G, B grayscale data, the gate The control signal output to the driver 120 includes a vertical synchronization start signal Vstart corresponding to the vertical synchronization signal and a gate clock signal GCLK for sequentially applying a gate signal to each of the gate lines G1 to Gn. do. In addition, the control signal output to the power converter 222 defines the period and amplitude of the common voltage.

In response to the control signal of the timing controller 221, the power converter 222 steps down or boosts the input voltage DVDD applied from the power supply unit (not shown) to convert to an appropriate voltage level, and converts the input voltage in a digital form ( DVDD) is converted into an analog type liquid crystal drive voltage AVDD and outputted. As the power converter 222, it is preferable to use a conventional DC-DC converter.

The gray voltage generator 223 outputs gray voltages having different voltage levels according to the luminance by using the gray data input from the timing controller 221 and the liquid crystal driving voltage DVDD input from the power converter 222. do.

3 is a circuit diagram illustrating a configuration circuit of a gray voltage generator of a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the gray voltage generator 223 may be configured using a resistance string connected in series between the power converter 222 and the ground. At this time, the upper voltage becomes the liquid crystal driving voltage AVDD input from the power converter 222, the lower voltage becomes the ground voltage, and the voltage divided by the node of each resistor connected in series is the gray level voltage GMA1 to GMAn. ) In the present exemplary embodiment, the gray voltage generator 223 is configured as a resistor string connected in series, but this is merely an example for description and may be configured in other ways such as a variable resistor or digital resistor.

The reference voltage generator 224 outputs the common voltage Vcom applied to the common electrode by using the liquid crystal driving voltage AVDD input from the power converter 222, and gate-on applied to the gate driver 120. The voltage Von and the gate-off voltage Voff are output.

The data driver 110 applies a data signal to each of the data lines D1 to Dm in response to the horizontal synchronization start signal of the timing controller 221 and the gray voltage of the gray voltage generator 223, and the gate driver 120. ) Applies a gate signal to each gate line G1 to Gn in response to the vertical control signal of the timing controller 221 and the gate on-off voltage of the reference voltage generator 224. The data driver 110 and the gate driver 120 may include a driving chip which is directly mounted in the COG method on the mounting area A1 of the liquid crystal display panel 100 or a driving chip formed when the liquid crystal display panel 100 is manufactured. It is preferable to use.

Meanwhile, various control signals generated and output from the driving circuit board 200 are transferred to the data driver 110 and the gate driver 120 formed in the liquid crystal display panel 100 through the flexible printed circuits 300a and 300b. . That is, a connection pattern electrically connected to the data driver 110 and the gate driver 120 is formed in the mounting area A1 of the liquid crystal display panel 100, and the control signal is also applied to one side of the driving circuit board 200. Connection patterns for output are formed so that the connection patterns on both sides are electrically connected to one ends of the flexible printed circuits 300a and 300b, respectively. At this time, the flexible printed circuits 300a and 300b are formed with wires for connecting the connection patterns of both sides, and the wirings are formed in a multilayer, which is more advantageous for miniaturization, and the flexible printed circuits 300a and 300b and the connection patterns may be formed. The connection is preferably an anisotropic conductive film (ACF).

The flexible printed circuits 300a and 300b may be connected to the data driver 110, may be connected to the gate driver 120, and may be connected to both the data driver 110 and the gate driver 120. .

Next, the operation of the liquid crystal display having the above configuration will be briefly described.

The graphic controller 210 receiving an image signal from the outside generates a digital signal including image signals of R, G, and B and a synchronization signal, and the liquid crystal driver 220 drives the liquid crystal display panel 100 in response thereto. Various control signals suitable for characteristics are generated and transmitted to the data driver 110 and the gator driver 120. In this case, the liquid crystal driver 220 may use the serial mode, that is, the CICC (Current mode interface Cascade COG; CICC) method so that the data driver 110 and the gator driver 120 may transmit a control signal to another chip through an adjacent driving chip. It is desirable to send to. The CICC method can reduce power consumption and reduce transmission lines between driving chips.

Meanwhile, the data driver 110 applies a data control signal including the gray voltage generated by the gray voltage generator 223 to each of the data lines D1 to Dm, and the gate driver 120 includes the reference voltage generator. The gate control signal including the gate on voltage Von and the gate off voltage Voff generated at 224 is applied to each of the gate lines G1 to Gn.

When a data control signal is applied to a specific data line and a gate control signal is applied to a specific gate line, a specific pixel corresponding to the intersection area is selected. In this case, the thin film transistor of the selected pixel is turned on to form an electric field between the pixel electrode and the common electrode, thereby changing the molecular arrangement of the liquid crystal layer, thereby changing the transmittance of light incident from the rear surface. Thereafter, the light transmitted through the liquid crystal layer is colored by the red (R), green (G), and blue (B) color filters and emitted to the front, and the light emitted from each pixel is mixed to implement a color image.

4 is a block diagram illustrating a connection relationship between a graphic controller and a timing controller in a liquid crystal display according to a comparative example and an application example of the present invention. Here, (a) shows the connection relationship between the graphic control unit and the timing control unit in the liquid crystal display according to the comparative example of the present invention, and (b) shows the graphic control unit and timing in the liquid crystal display device according to the application example of the present invention. It is a block diagram which shows the connection relationship of a control part.

In the conventional case as shown in (a), the graphic controller 410 and the timing controller 420 require a protocol for signal transmission, that is, an LVDS transmitter and an LVDS receiver that satisfy the LVDS standard, and require a connector for connection. Do. On the other hand, in the case of the present invention as shown in (b), since the graphic controller 121 and the timing controller 122 are directly connected, there is no need for connection means such as an LVDS transmitter, an LVDS receiver, and a connector.

As such, in the liquid crystal display according to the exemplary embodiment of the present invention, since the graphic controller 210 and the liquid crystal driver 220 are integrally formed on the driving circuit board 200, connection means for transmitting and receiving signals, for example, Since no protocols and connectors are needed, manufacturing costs can be reduced. In addition, since the digital signal generated by the graphic controller 210 is transmitted to the liquid crystal driver 220 as it is, a separate analog-digital converting or digital-analog converting is not necessary. The fall can be prevented. In addition, since the graphic controller 210 and the liquid crystal driver 220 are integrated, there is an advantage in that the compatibility and suitability with the graphic controller 210 can be sufficiently tested in advance.

As described above, the above embodiments are disclosed for purposes of illustration, and those skilled in the art will appreciate that various modifications, improvements, substitutions, and additions may be made without departing from the spirit of the present invention. Accordingly, the technical scope of the present invention is defined by the appended claims.

As described above, in the present invention, the graphic control unit for generating the image signal and the liquid crystal drive unit for controlling the liquid crystal display panel are integrally formed. Therefore, the following effects can be expected.

First, a connection means such as a protocol, a connector, etc. for sending and receiving a signal can be omitted, thereby reducing manufacturing costs.

In addition, since the digital signal generated by the graphic controller is transmitted to the liquid crystal driver as it is, a separate analog-digital converting or digital-analog converting is not necessary, and the original signal is distorted during the converting process, thereby preventing the display quality from being degraded. have.

In addition, the compatibility and suitability of the graphic controller and the liquid crystal driver can be sufficiently tested in advance.

Claims (6)

A display area and a mounting area, wherein the liquid crystal display panel includes a data driver and a gate driver; And a graphic circuit controller for outputting an image signal, and a driving circuit board in which a liquid crystal driver for receiving the image signal and converting the image signal into a control signal suitable for driving characteristics of the liquid crystal display panel is output. The method according to claim 1, And the data driver and the gate driver are driving chips mounted directly on the liquid crystal display panel in a COG manner. The method according to claim 1, And the data driver and the gate driver are driving chips formed together when the liquid crystal display panel is manufactured. The method according to claim 1, And a flexible printed circuit for transmitting a control signal output from the driving circuit board to the liquid crystal display panel. The method according to claim 4, And the flexible printed circuit is formed of a multilayer wiring. The method according to claim 1, And the liquid crystal driver applies control signals to the data driver and the gate driver in a current mode interface cascade COG (CICC) method for transmitting data to another chip through an adjacent driver chip.

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