KR20050094015A - Liquid crystal display device and driving method thereof - Google Patents

Abstract

The present invention discloses a liquid crystal display device and a method of driving the same, which enable display of clearer and more natural images by implementing panel characteristics suitable for moving images and still images. Disclosed is a liquid crystal display device including an LCD module including a liquid crystal panel and a driver IC, a CPU, a backlight unit, and an LED light source main PCB, wherein the plurality of LEDs are configured and displayed in addition to the LED light source. If the image to be a video image is a data transfer between the external input module and the LCD module via the RGB interface, and if the data to be displayed is a still image image, data is transferred between the CPU and the LCD module through the system interface. It is characterized by.

Description

Liquid crystal display and its driving method {LIQUID CRYSTAL DISPLAY DEVICE AND DRIVING METHOD THEREOF}

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 and a method of driving the same, capable of expressing a clearer and more natural image by implementing appropriate panel characteristics corresponding to images of moving pictures and still images.

In general, a liquid crystal display device is a display device that displays an image by adjusting the light transmittance of a liquid crystal having dielectric anisotropy using an electric field.

Such a liquid crystal display device is largely composed of a liquid crystal panel in which liquid crystal cells are arranged in a matrix to display an image, and a driving circuit for driving the liquid crystal panel.

The driving circuit may include a gate driver IC for driving gate lines of a liquid crystal panel, a data driver IC for driving data lines intersected with the gate line, and various timing control signals to the gate driver IC and the data driver IC. And a timing control section for supplying data, and a power supply section for supplying a power supply voltage.

The data driver IC and the gate driver IC are divided into a plurality of integrated circuits and integrated in a chip form, and each of the driver ICs is mounted on a tape carrier package (TCP) to be tape-automated bonding (TAB). It is electrically connected with the liquid crystal panel.

The liquid crystal panel is composed of two glass substrates and a liquid crystal layer enclosed therebetween, and a gate line and a data line defining a pixel region are intersected on the lower substrate, and each pixel region includes a pixel electrode and the gate line. A thin film transistor that is switched by a driving signal and applies a signal of a data line to the pixel electrode is disposed, and a black matrix is formed on the upper substrate to block light from being transmitted to an area except the pixel electrode, and the black matrix is interposed therebetween. The color filter layer is formed in each pixel area, and the common electrode is formed on the front surface.

Such a liquid crystal display device is used in various ways such as a computer monitor, a TV and a mobile phone, and when used in a mobile phone, the module configuration is as shown in FIG.

As shown in FIG. 1, a conventional mobile phone liquid crystal display device includes a liquid crystal panel 1, a driver IC 2, a backlight unit 3, an LED light source 4, and a main printed circuit board (PCB). (5) and FPC (Flexible Printed Circuit) 6.

Here, the liquid crystal panel 1 displays an image by applying data to a pixel area defined by a gate line and a data line, and is composed of two glass substrates.

The driver IC 2 includes a source driver IC for applying a data signal to the data line and a gate driver IC for applying a gate signal to the gate line. The driver IC 2 includes various timing control signals using the source driver IC and the gate driver IC. And a timing controller for outputting a data signal, a DC / DC converter, and a gamma voltage generator for applying a gamma voltage.

The backlight unit 3 is similar to a backlight system of a general TFT-LCD, but has a structure for changing a point light source of an LED to a surface light source.

The main PCB 5 is composed of a CPU interface unit, an RGB interface unit, and an LED driver unit. An 18-bit interface signal (varies depending on the system) and control signals, for example, an RS, CS, WR signal, and the like from the system. Receive or RGB interface signal from an external module.

According to the liquid crystal display device according to the related art configured as described above, the driver IC 2 is selected by a CS (Chip Select) signal, and data including various information for driving the LCD includes an address and a command. It is set in batch via the 18bits interface bus.

However, the conventional liquid crystal display device as described above has a setting by a batch of data transmission and a constant panel characteristic (Brightness, Gamma voltage, etc.), so that the still image and the moving image image are not natural in actually representing the image. In addition, the LED also had a problem of being driven inefficiently.

An object of the present invention is to provide a liquid crystal display device and a method of driving the same, which can display a clearer and more natural image by implementing panel characteristics suitable for a moving picture or a still image.

The liquid crystal display device of the present invention for achieving the above object is a liquid crystal display device comprising an LCD module including a liquid crystal panel and a driver IC, a CPU, a backlight unit, an LED light source main PCB, In addition, if a plurality of LEDs are configured, and the image to be displayed is a moving image, data transmission is performed between the external input module and the LCD module through an RGB interface. It is characterized by the data transfer between the CPU and the LCD module.

Here, the system interface is composed of a command bit and a data bit, and the additionally configured plurality of LEDs are turned on when the image to be displayed is a moving image and off when the image to be displayed is a still image. OFF) state.

On the other hand, the driving method of the liquid crystal display device as described above is a liquid crystal display device driving method comprising an LCD module including a liquid crystal panel and a driver IC, and a CPU, a backlight unit, and an LED light source main PCB. In the case where the image to be displayed is a moving image and a still image, the data is transmitted to the LCD module through different interfaces.

Here, when the image to be displayed is a moving image, data is transmitted between the external input module and the LCD module through an RGB interface, and when the data to be displayed is a still image image, the CPU and the LCD module are connected through a system interface. It is characterized by transmitting data.

In addition, the method of driving the liquid crystal display of the present invention preferably transmits gamma data corresponding to the moving image or the still image before the moving image or the still image image data is transmitted.

Hereinafter, a liquid crystal display and a driving method thereof of the present invention will be described with reference to the accompanying drawings.

2 is a schematic block diagram illustrating a liquid crystal display of the present invention, and FIG. 3 is a conceptual diagram illustrating an interface method according to the method of driving the liquid crystal display of the present invention.

First, as shown in FIG. 3, the liquid crystal display of the present invention uses two interfaces to drive the LCD module.

One of them is a system interface between the CPU 10 and the LCD module 12, and the other is an RGB interface composed of 18 bits between the CPU 10 or the external input module and the LCD module 12.

In this case, the system interface is composed of 6-bit, 8-bit, 16-bit, 18-bit data, and the bits are composed of a command and data.

Such a system interface generates a 16-bit command along with control signals according to a predetermined procedure to generate all the information about the LCD module 12 using a register built in the driver IC, for example, gamma voltage, After transmitting information related to the driving method, Von / Voff, etc., the CPU 10 is ready to send data and sends a still image.

Accordingly, the liquid crystal display device of the present invention implements the moving image and still image as shown in FIG. 4 while the CPU 10, the external input module (not shown), and the LCD module 12 are interlocked by using the system interface and the RGB interface described above. It becomes the number.

For example, when the LCD module 12 is ready to be driven by the command of the system interface, the moving image image and the still image image are stored in the internal memory of the driver IC using different interface methods, and then sent to the liquid crystal panel. do.

Here, the gamma data is transmitted in advance before the moving image is sent, and the still image also satisfies the conditions required for the moving image and the still image by sending the gamma voltage accordingly before the still image is sent.

At this time, the CPU 10 requires the write enable signal 1 (WR1), the write enable signal 2 (Write Enable 2: WR2), and the chip select signal (Chip Select) to perform the respective procedures. .

Hereinafter, the software setting and the hardware setting will be described.

First, the software setting sequence is as follows.

First, 16-bit commands for the gamma data (system interface)

At this time, the CS for selecting the source driver IC is "Low" and WR1 is "High".

Second, 18-bit still image data (system interface)

At this time, CS is "Low" and WR1 is "High", and gamma data suitable for still images is secured.

Third, 16-bit command for gamma data (system interface)

At this time, CS is "Low" and WR1 is "High".

Fourth, 18-bit video image data (RGB interface)

At this time, CS is "Low", WR2 is "High" state, to ensure gamma data suitable for the video image.

Fifth, 16-bit command for gamma data (system interface)

At this time, CS is "Low" and WR1 is "High".

Sixth, 18-bit still image data (system interface)

At this time, CS is "Low" and WR1 is "High", and gamma data is secured for still images.

On the other hand, the hardware setting is made as follows, two control signals are required for effective LED driving by the hardware setting.

This will be described with reference to the LED driving circuit of the present invention shown in FIG.

The control signals required for the effective LED driving mentioned above are the control_1 signal and the control_2 signal shown in FIG. 5.

First, the control_1 signal is a control signal (LED enable signal) for the PWM (Pulse Width Modulation) control block 51, and the control_2 signal is on / off control of the switch for the added LED 7 shown in FIG. 2. As a write enable signal, these signals are output from the CPU 10.

In particular, the control_2 signal is a control signal for generating high brightness when a video image is to be expressed. When the control_2 signal is “high” when a video is expressed through an RGB interface, the control_2 signal corresponds to a switch 53. The Field Effect Transistor (FET) operates to produce high brightness (about 200 cd / m 2 or more) while turning on the added LED 7.

If it is desired to represent an image of a still image such as information data, the control_2 signal is set to "low", and thus the switch 53 is also turned off, so the additional LED 7 is also turned off. Becomes

As described above, when the moving image is turned on, the additional LED 7 is turned on to generate high brightness, and in the case of a still image, the additional LED 7 is turned off to drive the LED to a minimum, thereby increasing energy efficiency.

For reference, the hardware settings are made in the following order.

First, 18-bit still image data input

Second, control signal input ⇒ Existing LED ON

Third, 18-bit video image data input

Fourth, control signal input ⇒ additional LED ON

Although the preferred embodiments of the present invention have been described above, it is clear that the present invention can use various changes, modifications, and equivalents, and that the above embodiments can be appropriately modified and applied in the same manner. Accordingly, the above description does not limit the scope of the invention as defined by the limitations of the following claims.

As described above, the liquid crystal display of the present invention has the following effects.

If the image to be displayed on the liquid crystal panel is image data, the data is transferred between the external input module and the LCD module through the RGB interface. If the image to be displayed on the liquid crystal panel is a still image, the CPU and the LCD module are transferred through the system interface. By using the interface method to transmit the data, it is possible to express the clear and natural image suitable for the image by changing the number of tuning values and LEDs for the video and the still image.

1 is a block diagram of a liquid crystal display device according to the prior art.

2 is a block diagram of a liquid crystal display according to the present invention.

3 is a conceptual diagram illustrating an interface between an LCD module, a CPU, and an external input module according to the present invention;

4 is a view showing a liquid crystal display screen according to an image change according to the present invention.

5 is a configuration diagram of an LED driving circuit according to the present invention.

* Description of the symbols for the main parts of the drawings *

1: liquid crystal panel 2: driver IC

3: backlight unit 4: LED light source

5: main PCB 6: FPC

7: additional LED 10: CPU

12: LCD module 51: PWM control block

53: switch

Claims (7)

An LCD module including a liquid crystal panel and a driver IC, and a CPU, a backlight unit, and an LED light source main PCB. When a plurality of LEDs are configured in addition to the LED light source, and the image to be displayed is a video image, data is transmitted between an external input module and the LCD module through an RGB interface, and the data to be displayed is a still image image. There is a liquid crystal display, characterized in that the data transfer between the CPU and the LCD module via the system interface. The method of claim 1, wherein the system interface, A liquid crystal display device comprising command bits and data bits. The method of claim 1, wherein the plurality of LEDs, And if the image to be displayed is a moving image, the display unit is turned on. If the image to be displayed is a still image image, the liquid crystal display is turned off. In a method of driving a liquid crystal display device comprising an LCD module including a liquid crystal panel and a driver IC, and a CPU, a backlight unit, and an LED light source main PCB, When the image to be displayed on the liquid crystal panel is a moving image image and a still image image, a method of driving a liquid crystal display device, characterized in that for transmitting data to the LCD module through a different interface. The CPU of claim 4, wherein the data to be displayed is a moving image between the external input module and the LCD module through an RGB interface, and when the data to be displayed is a still image, the CPU and the system interface. And a method of transferring data between the LCD modules. The method of claim 5, wherein gamma data according to a still image and a moving image is transmitted in advance before the data is transmitted. According to claim 4, If the image to be displayed is a video image to implement a high brightness with more LED light source than the original LED light source, If the image to be displayed is a video image to implement the brightness of the original LED light source A method of driving a liquid crystal display device.