KR20110075252A - Driving circuit for liquid crystal display device and method for driving the same - Google Patents

Abstract

PURPOSE: A device and method for driving a liquid display device are provided to minimize power consumption by driving a backlight with the minimum power in a mood lighting function. CONSTITUTION: A liquid crystal panel has a plurality of pixel areas. A data driver(4) drives a plurality of data lines. A gate driver(6) drives a plurality of gate lines. A timing controller controls the gate and data drivers to display preset mode image data on a liquid crystal panel if image data is not supplied from the outside and outputs a mood dimming signal corresponding to mode image data. A backlight controller(10) controls the brightness of a backlight unit(12) which irradiates light to the liquid crystal panel according to a mood dimming signal.

Description

DRIVING CIRCUIT FOR LIQUID CRYSTAL DISPLAY DEVICE AND METHOD FOR DRIVING THE SAME}

The present invention can be used for a variety of purposes, such as mood lighting function in addition to the main purpose for the user to display the image, and the liquid crystal display device to minimize the power consumption by driving the backlight with the minimum power consumption when the mood lighting function It relates to a driving device and a driving method thereof.

Recently, with the development of display device technology of flat panel display devices, thin display devices such as liquid crystal displays (PDPs) and plasma display panels (PDPs) have begun to be used as display devices of flat panel display devices. Among them, the liquid crystal display is most widely used among television display systems because it can be applied to small devices and large devices. Televisions using such liquid crystal displays are only a few centimeters thick and can be hung on a wall or even mounted on a ceiling.

However, the conventional television only had a function of displaying an image transmitted from a broadcasting station or displaying an image input from another external device (for example, VDR, VDP, etc.). These televisions do not meet the needs of consumers who want a product with more various functions because the television does not have a different function in the off state.

On the other hand, since the liquid crystal panel does not emit light by itself, a liquid crystal display device requires a backlight on the rear side of the liquid crystal panel. Such a backlight is divided into an edge method and a direct method according to the location where the lamp unit is installed. The light source may be an EL (Electro Luminescence), an LED (Light Emitting Diode), a CCFL (Cold Cathode Fluorescent Lamp), HCFL (Hot Cathode Fluorescent Lamp).

The backlight unit occupies a substantial portion of power consumption in a television employing a liquid crystal display. For this reason, there is an urgent need for technology development that reduces the power consumption of the backlight unit as the television becomes larger.

The problem to be solved by the present invention is that the user can be used for a variety of purposes, such as mood lighting function in addition to the main purpose to display the image, and also the power consumption by driving the backlight with the minimum power consumption when the mood lighting function It is an object of the present invention to provide a driving device of a liquid crystal display device and a driving method thereof.

In order to achieve the above object, a driving apparatus of a liquid crystal display according to an exemplary embodiment of the present invention includes: a liquid crystal panel including a plurality of pixel regions; A data driver for driving a plurality of data lines; A gate driver for driving a plurality of gate lines; A timing controller which controls the gate and data driver so that predetermined mood image data is displayed on the liquid crystal panel when no image data is supplied from the outside, and outputs a mood dimming signal corresponding to the mood image data; A backlight unit radiating light onto the liquid crystal panel; And a backlight controller for controlling the brightness of the backlight unit according to the mood dimming signal.

In addition, the driving method of the liquid crystal display device according to an embodiment of the present invention for achieving the above object, if the image data is not supplied from the outside to control the gate and data driver so that the predetermined mood image data is displayed on the liquid crystal panel Outputting a plurality of mood dimming signals corresponding to the mood image data; And controlling brightness of the backlight unit according to the mood dimming signal.

The driving apparatus and driving method thereof of the liquid crystal display according to the present invention may be used for various purposes such as a mood lighting function in addition to the main purpose of displaying an image by a user.

In addition, when the mood lighting function, the backlight can be driven with minimum power consumption to minimize power consumption.

Hereinafter, a driving apparatus and a driving method thereof of the liquid crystal display according to the present invention having the above characteristics will be described in detail with reference to the accompanying drawings.

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

A driving device of the liquid crystal display shown in FIG. 1 includes a liquid crystal panel 2 formed with a plurality of pixel regions; A data driver 4 for driving a plurality of data lines DL1 to DLm; A gate driver 6 driving a plurality of gate lines GL1 to GLn; If the image data is not supplied from the outside, the gate and data drivers 6 and 4 are controlled to display the preset mood image data MRGB on the liquid crystal panel 2 and correspond to the luminance of the mood image data MRGB. A timing controller 8 for outputting a mood dimming signal MDS; A backlight unit 12 for irradiating light onto the liquid crystal panel 2; The backlight controller 10 controls the brightness of the backlight unit 12 according to the mood dimming signal MDS.

The liquid crystal panel 2 includes a thin film transistor (TFT) formed in each pixel area defined by a plurality of gate lines GL1 to GLn and a plurality of data lines DL1 to DLm, and a TFT. A liquid crystal capacitor Clc is provided. The liquid crystal capacitor Clc is composed of a pixel electrode connected to a TFT and a common electrode facing each other with the pixel electrode and the liquid crystal interposed therebetween. The TFT supplies the data signals from the respective data lines DL1 to DLm to the pixel electrodes in response to the scan pulses from the respective gate lines GL1 to GLn. The liquid crystal capacitor Clc charges the difference voltage between the data signal supplied to the pixel electrode and the common voltage supplied to the common electrode, and adjusts the light transmittance by varying the arrangement of liquid crystal molecules according to the difference voltage. The storage capacitor Cst is connected to the liquid crystal capacitor Clc in parallel so that the voltage charged in the liquid crystal capacitor Clc is maintained until the next data signal is supplied. The storage capacitor Cst is formed by overlapping the pixel electrode with the previous gate line and the insulating layer interposed therebetween. In contrast, the storage capacitor Cst may be formed by overlapping the pixel electrode with the storage line and the insulating layer interposed therebetween.

The data driver 4 converts the data Data and mood data MData into analog image data according to the data control signal DCS from the timing controller 8, and scan pulses are applied to the gate lines GL1 to GLn. The analog image data for one horizontal line is supplied to the data lines DL1 to DLm for each horizontal period supplied. In other words, the data driver 4 selects a gamma voltage having a predetermined level according to the gray value of the analog image data and supplies the selected gamma voltage to the data lines DL1 to DLm.

The gate driver 6 sequentially generates scan pulses, for example, gate high pulses, and supplies them to the gate lines GL1 to GLn in response to the gate control signal GCS from the timing controller 8.

FIG. 2 is a configuration diagram illustrating the timing controller shown in FIG. 1.

The timing controller 8 shown in FIG. 2 includes a mood controller 22 which outputs mood image data MRGB when the image data RGB is not supplied; An image aligner 20 which aligns the image data RGB and the mood image data MRGB according to the resolution of the liquid crystal panel 2 and outputs data and mood data; A dimming control unit 24 for outputting a dimming signal DS and a mood dimming signal MDS corresponding to luminance of the data and mood data Mdata; The data driver control unit 26 for supplying the data control signal DDC to the data driver 4 in accordance with the synchronization signals HSync, VSync, DCLK, DE, and the synchronization signals HSync, VSync, DCLK, DE And a gate driver controller 28 for supplying a gate control signal GDC to the gate driver 6.

The mood controller 22 receives image data RGB in at least one frame unit. The mood controller 22 does not operate when the image data RGB is continuously input. On the other hand, the mood controller 22 determines that the power is turned off when the input of the image data RGB is interrupted for a predetermined frame or more, and supplies the preset mood image data MRGB to the image aligner 20 with reference to the memory. do. The mood image data MRGB may be a still image or a moving image for a mood lighting function. In addition, the memory may be embedded in the timing controller 8, and in some cases, may be an external memory.

The dimming controller 24 receives the data Data or the mood data MData of the image aligning unit 20. In this case, the mood image data MRGB of the mood controller 22 may be supplied instead of the mood data MData. The dimming controller 24 outputs a preset mood dimming signal MDS corresponding to the luminance of the mood data MData.

The mood dimming signal MDS may not be set in advance. At this time, the dimming control unit 24 detects the luminance of the supplied data (Data) or mood data (MData). Then, the dimming signal DS or the mood dimming signal MDS for individually driving the light source array of the backlight unit 12 is output according to the detected luminance. In this case, the dimming signal DS and the mood dimming signal MDS include duty ratio information for controlling the luminance of each light source array.

Meanwhile, the liquid crystal display according to the present invention may use EL, LED, CCFL, HCFL, or the like as the light source of the backlight lamp unit. Here, the case of using the LED as the light source of the backlight lamp unit will be described by way of example.

3 is a block diagram illustrating the backlight controller of FIG. 1.

The backlight controller 10 shown in FIG. 3 controls the backlight control signal BS whose on-off time of the backlight 12 is controlled according to the duty ratio included in each dimming signal DS of the timing controller 8. Mood backlight control in which the on-off time of the backlight unit 12 is controlled according to the duty ratio included in the plurality of first backlight controllers 30 and the mood dimming signal MDS of the timing controller 8. A plurality of second backlight control unit 30 for outputting the signal (MBS) is provided.

The plurality of first backlight controllers 30 may generate a first PWM modulator 32 to generate a pulse width modulation (PWM) signal according to the duty ratio included in the dimming signal DS of the timing controller 8. And a first transformer 33 for converting the output time of the DC input power according to the PWM signal PWM to output the backlight control signal BS.

The first PWM modulator 32 generates a PWM signal PWM for driving each LED according to the duty ratio included in the dimming signal DS. Here, the plurality of PWM signals PWM are signals for controlling the brightness of each LED to control the brightness of each LED by controlling the on-off time.

The first transformer 33 generates a backlight control signal BS in response to the PWM signal PWM. Specifically, the first transformer 33 converts the on-off time of the DC input power according to the PWM signal PWM to generate the backlight control signal BS in which the dimming value is modulated. Here, the backlight control signal BS is a control signal that makes the current flowing to the LED constant for uniform light irradiation, and adjusts the voltage across the LED to make the current flowing to the LED constant. At this time, the first transformer 33 may adjust the brightness of the LED by varying the on-off time of the LED or the voltage level of the backlight control signal BS.

The plurality of second backlight controllers 31 may include a second PWM modulator 34 which generates a mood PWM signal MPWM according to a duty ratio included in the mood dimming signal MDS of the timing controller 8, The second transformer 35 converts the output time of the DC input power according to the mood PWM signal MPWM and outputs the mood backlight control signal MBS.

The second PWM modulator 34 generates a mood PWM signal MPWM for driving each LED according to the duty ratio included in the mood dimming signal MDS. Here, the plurality of mood PWM signals (MPWM) is a signal for controlling the brightness of each LED may also control the brightness by controlling the on-off time of each LED.

The second transformer 33 generates a mood backlight control signal MBS in response to the mood PWM signal MPWM. Specifically, the second transformer 33 converts the on-off time of the DC input power according to the mood PWM signal MPWM to generate the mood backlight control signal MBS modulated with a dimming value. Here, the mood backlight control signal MBS is a control signal that makes the current flowing in the LED constant for uniform light irradiation, and makes the current flowing in the LED constant by adjusting the voltage across the LED. At this time, the second transformer 33 may adjust the brightness of the LED by varying the on-off time of the LED or the voltage level of the mood backlight control signal MBS.

4 is a configuration diagram illustrating the backlight illustrated in FIG. 1.

The backlight unit 12 illustrated in FIG. 4 includes a light guide plate 40 which uniformly transmits light emitted from the backlight unit to the entire surface of the liquid crystal panel 2, and the light guide plate 40 according to the backlight control signal BS. And a plurality of image LED arrays 50 to 53 for irradiating light to the light guide plate, and a plurality of mood LED arrays 56 and 58 for irradiating light to the light guide plate 40 according to the mood backlight control signal MBS. do.

The light guide plate 40 evenly spreads the light emitted from the LED array to maintain the uniformity of brightness and color in the liquid crystal panel 2. In addition, although not shown, the light guide plate 40 may be selectively stacked with any one of a diffusion sheet for diffusing light emitted from the liquid crystal panel 2 in various directions or a prism sheet which serves to collect the light into the front viewing angle. An optical sheet for improving the luminance may be provided.

The image LED arrays 50 to 53 are disposed on at least one side of the light guide plate 40. Such image LED arrays 50 to 53 are composed of a plurality of LED blocks.

The LED block includes one or more LED chips, each LED block of which the brightness is adjusted by the different backlight control signal (BS) to irradiate light to the light guide plate (40).

The mood LED arrays 56 and 58 are disposed on either side of the light guide plate 40. These mood LED arrays 56, 58 consist of a number of mood LED blocks.

The mood LED block includes one or more mood LED chips, and each mood LED block has its brightness controlled by a different mood backlight control signal MBS to irradiate light to the light guide plate 40.

The brightness of the mood LED arrays 56 and 58 may be based on the brightness of the actual picture frame according to the illumination to maintain the minimum power consumption. That is, the luminance of the mood LED arrays 56 and 58 may be set to about 35 to 45 nit at 200 to 400 lux (surface roughness: 80 to 160 lux) which is an indoor illumination environment.

On the other hand, the above-described backlight unit 12 is an edge-type system in which the position of the LED array is disposed on the side of the light guide plate 40. In addition to the edge type method described above, the backlight unit 12 may be a direct type method in which the position of the LED array is formed under the liquid crystal panel 2.

Referring to FIG. 5, the backlight unit 12 includes a plurality of image LED arrays 60 and a mood backlight control signal MBS for irradiating light to the liquid crystal panel 2 according to the backlight control signal BS. The panel 2 is provided with a plurality of mood LED arrays 66 for irradiating light.

In this case, individual operations of each image LED array 60 and each mood LED array 66 may be applied in the same manner as the above-described driving method.

As described above, the driving device and the driving method of the liquid crystal display according to the present invention may be used as a decorative article by displaying a preset image when the power is turned off, and a backlight unit separately provided when displaying the preset image. Can be operated with the minimum power consumption to minimize power consumption.

The present invention described above is not limited to the above-described embodiment and the accompanying drawings, it is conventional in the art that various substitutions, modifications and changes are possible without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

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

FIG. 2 is a configuration diagram of the timing controller shown in FIG. 1. FIG.

3 is a block diagram of the backlight controller illustrated in FIG. 1.

4 is a configuration diagram illustrating a backlight unit illustrated in FIG. 1.

FIG. 5 is a configuration diagram illustrating the backlight unit illustrated in FIG. 1. FIG.

* Brief description of symbols for the main parts of the drawings.

 8: Timing Controller 10: Backlight Control

12: backlight 22: mood control

24: dimming controller 32: PWM modulator

Claims (8)

A liquid crystal panel formed with a plurality of pixel regions; A data driver for driving a plurality of data lines; A gate driver for driving a plurality of gate lines; A timing controller which controls the gate and data driver so that predetermined mood image data is displayed on the liquid crystal panel when no image data is supplied from the outside, and outputs a mood dimming signal corresponding to the mood image data; A backlight unit radiating light onto the liquid crystal panel; And And a backlight controller configured to control the brightness of the backlight unit in response to the mood dimming signal. The method of claim 1, The timing controller is A mood controller configured to output the mood image data when the image data is not supplied; An image alignment unit to align the image data and the mood image data to the resolution of the liquid crystal panel to output data and mood data; A dimming controller configured to generate a plurality of dimming signals corresponding to the luminance of the data and the mood data and the mood dimming signal; A data driver control unit for supplying a data control signal to the data driver in accordance with a synchronization signal; And a gate driver controller for supplying a gate control signal to the gate driver by using the synchronization signal. The method of claim 2, The backlight control unit A plurality of first backlight controllers for outputting a backlight control signal to control an on-off time of the backlight unit according to a duty ratio included in each of the dimming signals of the timing controller; And a plurality of second backlight controllers configured to output a mood backlight control signal to control an on-off time of the backlight unit according to a duty ratio included in each mood dimming signal of the timing controller. Drive. The method of claim 3, wherein The backlight unit A light guide plate for uniformly transmitting light incident from a lower side or side surface to the entire surface of the liquid crystal panel; A plurality of image light source arrays for irradiating light from the bottom or the side of the light guide plate according to the backlight control signal; And a plurality of mood light source arrays for irradiating light from the bottom or the side of the light guide plate according to the mood backlight control signal. If the image data is not supplied from the outside, controlling the gate and the data driver to display the preset mood image data on the liquid crystal panel and outputting a plurality of mood dimming signals corresponding to the mood image data; And And controlling brightness of a backlight unit according to the mood dimming signal. The method of claim 5, The outputting of the plurality of mood dimming signals may include Outputting the mood image data when the image data is not supplied; Outputting the data and the mood data by aligning the image data and the mood image data to the resolution of the liquid crystal panel; and And generating a plurality of dimming signals and the mood dimming signal corresponding to the luminance of the data and the mood data. The method of claim 6, Controlling the brightness of the backlight unit Controlling an on-off time of the backlight unit according to a duty ratio included in each of the dimming signals, and And controlling an on-off time of the backlight unit according to a duty ratio included in each of the mood dimming signals. The method of claim 7, wherein Controlling the brightness of the backlight unit Irradiating light onto the liquid crystal panel according to the duty ratio included in each of the dimming signals using the image light source array of the backlight unit; and And irradiating light to the liquid crystal panel according to the duty ratio included in each mood dimming signal using the mood light source array of the backlight unit.

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