KR101604496B1 - Liquid Crystal Display device - Google Patents

Abstract

A liquid crystal display device is disclosed.

A liquid crystal display device according to the present invention includes a liquid crystal display panel in which a plurality of gate lines and a plurality of data lines are arranged and displays an image, and a gate driver for supplying a scan signal to the gate lines. A data driver for supplying data to the data line; a light emitting diode array for emitting light to the liquid crystal display panel; and a controller for analyzing image data to be input to the liquid crystal display panel, A letter box area luminance controller for calculating a letter box area which is a black margin appearing at a lower end and generating a control signal for controlling the luminance of the LED array corresponding to the calculated letter box area; And a light emitting diode driver driving the light emitting diodes included in the light emitting diode array and driving the light emitting diodes corresponding to letter box regions of the liquid crystal display panel according to a control signal provided from the letter box region luminance controller do.

Letter box, backlight, power consumption, light emitting diode array

Description

[0001] The present invention relates to a liquid crystal display device,

The present invention relates to a liquid crystal display (LCD) device, and more particularly to a liquid crystal display device in which a light emitting diode array is arranged in a vertical direction, an input image is analyzed to convert a letter box area according to a standard specification, box region of the liquid crystal display device, thereby reducing power consumption.

CRT (Cathode Ray Tube), one of the commonly used display devices, is mainly used for monitors such as TVs, measurement devices, information terminals, etc. However, due to the weight and size of the CRT itself, We could not actively cope with the demand.

In order to replace such a CRT, a liquid crystal display device having advantages such as small size, light weight and low power consumption has been actively developed, and in recent years, it has sufficiently played a role as an ultra-thin flat display device in which the thickness of a display screen is only a few centimeters It was developed to the extent possible.

Since such a liquid crystal display device is a light-receiving device that displays an image by adjusting the amount of light coming from the outside, a separate light source for illuminating the liquid crystal display panel, that is, a backlight device is necessarily required.

The performance required for the backlight device must maintain a uniform luminance on a wide surface and maintain a sufficient luminance in consideration of a light transmittance of the liquid crystal display panel of less than 10%. In recent years, a cold cathode fluorescent lamp (CCFL) has been used as a light source of a backlight device. However, in recent years, it has become possible to use a light emitting diode (LED) And the use of such devices has been increasing. That is, a plurality of light emitting diodes are mounted on a substrate and used as a light source of a backlight device.

On the other hand, when a moving picture is displayed on a liquid crystal display panel in a liquid crystal display device having such a backlight device, a black margin called a letter box appears on the top and bottom of the liquid crystal display panel to match the aspect ratio Lt; / RTI > A light emitting diode (LED) used as a light source of the backlight device is always on when a moving picture in which the letter box is displayed is displayed on the liquid crystal display panel. In the case of the letter box, the black margin is present, but the power consumption is lost because the light emitting diode (LED) is always on.

In the present invention, a light emitting diode array is arranged in a vertical direction, an input image is analyzed, a letter box area according to a standard standard is converted, and a luminance of a backlight of the converted letter box area is calculated And a liquid crystal display device capable of reducing power consumption by controlling the power consumption of the liquid crystal display device.

A liquid crystal display device according to the present invention includes a liquid crystal display panel in which a plurality of gate lines and a plurality of data lines are arranged and displays an image, and a gate driver for supplying a scan signal to the gate lines. A data driver for supplying data to the data line; a light emitting diode array for emitting light to the liquid crystal display panel; and a controller for analyzing image data to be input to the liquid crystal display panel, A letter box area luminance controller for calculating a letter box area which is a black margin appearing at a lower end and generating a control signal for controlling the luminance of the LED array corresponding to the calculated letter box area; And a light emitting diode driver driving the light emitting diodes included in the light emitting diode array and driving the light emitting diodes corresponding to letter box regions of the liquid crystal display panel according to a control signal provided from the letter box region luminance controller do.

A liquid crystal display (LCD) device according to the present invention arranges an input light emitting diode array in a vertical direction, analyzes a input image to calculate a letter box area according to a standard specification, the power consumption can be reduced by arranging the light emitting diodes on the substrate so as to match the ratio of the letter box area and adjusting the brightness of the light emitting diode according to the ratio of the letter box area.

Hereinafter, embodiments according to the present invention will be described with reference to the accompanying drawings.

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

1, a liquid crystal display according to an exemplary embodiment of the present invention includes a plurality of gate lines GL1 to GLn and a plurality of data lines DL1 to DLm, A gate driver 110 for supplying a scan signal to the gate lines GL1 to GLn and a data line DL1 to DLm for supplying a scan signal to the gate lines GL1 to GLn, A timing controller 130 for controlling the gate driver 110 and the data driver 120 and a timing controller 130 for controlling the vertical direction of one side of the liquid crystal display panel 100 A light emitting diode array 140 disposed on the rear surface of the liquid crystal display panel 100 and configured to condense and diffuse the light emitted from the light emitting diode array 140, And an optical sheet 150 which is made of a transparent material.

Also, the liquid crystal display according to the embodiment of the present invention analyzes the inputted image data, calculates a letter box area, which is a black margin of the image data, and calculates the luminance of the letter box area And a backlight driver 170 for driving the light emitting diodes included in the light emitting diode array 140. The light emitting diode array 140 includes a light emitting diode (LED)

At this time, the light emitting diode array 140 and the optical sheets 150 constitute a backlight unit 200.

The liquid crystal display panel 100 includes a plurality of mutually intersecting gate lines GL1 to GLn and a plurality of data lines DL1 to DLm. The thin film transistors TFT formed at the intersections of the plurality of gate lines GL1 to GLn and the plurality of data lines DL1 to DLm are connected to the data lines DL1 to DLn in response to scan signals from the gate lines GL1 to GLn, DLm to the liquid crystal cell Clc. To this end, the gate electrode of the thin film transistor TFT is connected to the gate lines GL1 to GLn, and the source electrode thereof is connected to the data lines DL1 to DLm. The drain electrode of the thin film transistor TFT is connected to the pixel electrode of the liquid crystal cell Clc.

A storage capacitor Cst for holding the voltage of the liquid crystal cell Clc is formed on the liquid crystal display panel 100. The storage capacitor Cst may be formed between the liquid crystal cell Clc and a separate common line.

The gate driver 110 correspondingly supplies scan signals to a plurality of gate lines GL1 to GLn in response to a gate control signal GCS from the timing controller 130. [ The plurality of scan signals cause the plurality of gate lines GL1 to GLn to be sequentially enabled for one horizontal synchronous signal period.

The data driver 120 generates a plurality of pixel data voltages each time one of the plurality of gate lines GL1 to GLn is enabled in response to a data control signal DCS from the timing controller 130 And supplies them to the plurality of data lines DL1 to DLm on the liquid crystal display panel 100, respectively.

 The timing controller 130 receives synchronization signals (Vsync, Hsync) supplied from an external system (for example, a graphics module of a computer system or a video demodulation module of a television receiving system, not shown) A gate control signal GCS for controlling the gate driver 110 and a data control signal DCS for controlling the data driver 120 are generated using a clock signal DE and a clock signal CLK. In addition, the timing controller 130 arranges image data (Data) input from an external system and supplies the aligned data to the data driver 120. [

The light emitting diode array 140 constituting the backlight unit 200 includes a plurality of light emitting elements. The light emitting device includes a light emitting device that emits red, green, and blue light, and emits white light through a combination of red, green, and blue. The optical sheets 150 include a light guide plate for providing the white light emitted from the light emitting element of the light emitting diode array 140 to the liquid crystal display panel 100 and a prism sheet and a diffusion sheet for collecting and diffusing the white light do.

The letter box area luminance controller 160 analyzes the image input from the timing controller 130 and displays a letter box area of a black margin appearing when a moving picture is displayed on the liquid crystal display panel 100 And generates a control signal for controlling the luminance of the light emitting device corresponding to the calculated letter box area.

The backlight driver 170 generates a driving voltage for turning on / off a light emitting element located in the letter box region according to a control signal from the letter box region luminance controller 160 . Also, the backlight driver 170 generates a driving voltage for driving the light emitting devices located in the remaining areas except the letter box area.

FIG. 2 is a detailed block diagram of the letterbox area luminance controller of FIG. 1. Referring to FIG.

1 and 2, the letterbox area luminance controller 160 receives an image data from the timing controller 130 and analyzes image data according to a standard standard, A letter box area that is a black margin appearing in the upper / lower part when the moving picture is displayed on the liquid crystal display panel 100 according to the result analyzed by the image data analysis unit 161; An image area average luminance analyzer 165 for analyzing an average luminance of an image area excluding a letter box area conversion unit 163 and a letter box and an image area average luminance analyzer 165 A comparator 167 for comparing the result of the comparison with the reference value and generating a comparison signal according to the comparison result, and a comparator 166 for comparing the converted letter box area On And a on / off of the light emitting element per (On / Off) letter box, for generating a luminance control signal for controlling the timing (letter box), area luminance control signal generating portion 169.

The image data analyzing unit 161 receives data for displaying a moving image out of the sorted data in the timing controller 130 and determines whether the moving image data corresponds to a certain standard (e.g., Academy Standard Standard or Cinema Scope Standard) .

The letter box area conversion unit 163 determines which standard format the moving image data corresponds to in the image data analysis unit 161 and then converts the letter box area corresponding to the standard format into a ratio .

For example, when the moving picture data is data corresponding to the Academy Standard standard, the ratio of the letter box area of the liquid crystal display panel 100 may be converted to 4.52%. In addition, if the moving picture data is data conforming to the Cinema Scope standard, the ratio of the letter box area of the liquid crystal display panel 100 may be converted to 32.77%.

The image area average luminance analyzer 165 extracts a letter box area converted from the letter box area converter 163 and calculates an average luminance of data corresponding to an image area displaying the image . The image area average luminance analyzer 165 analyzes the average luminance of the image area and provides the analyzed luminance to the comparator 167.

The comparator 167 compares the average luminance value of the image region analyzed by the image area average luminance analyzer 165 with a preset reference value and generates a comparison signal according to the comparison result. The comparator 167 generates a comparison signal having a logic high when the average luminance value of the image area is higher than the reference value and outputs a comparison signal having a low logic when the average luminance value of the image area is lower than the reference value. Signal. The comparison signal generated by the comparator 167 is provided to the letter box region luminance control signal generator 169.

The letter box area luminance control signal generator 169 generates a luminance control signal for controlling the luminance of the converted letter box area according to the logical value of the comparison signal provided from the comparator 167. [ .

Specifically, when the high-logic comparison signal is supplied from the comparator 167, the letter box area luminance control signal generator 169 generates a luminance control signal having a predetermined PWM duty ratio of 30% To the backlight driver 170 of FIG. When a low logic comparison signal is supplied from the comparator 167, the letter box area luminance control signal generator 169 outputs a luminance control signal having a preset PWM duty ratio of 0 to 30% Signal to the backlight driver 170 of FIG.

The luminance control signal generated by the letter box region luminance control signal generating unit 169 is used to control the luminance of the light emitting device corresponding to the letter box region of the upper and lower sides of the liquid crystal display panel 100 Signal.

Accordingly, when a luminance control signal having a PWM duty ratio of 0% is supplied to the backlight driving unit 170, the backlight driving unit 170 turns off the light emitting device corresponding to the letter box area. When the luminance control signal having the PWM duty ratio of 30% is supplied to the backlight driving unit 170, the backlight driving unit 170 drives the light emitting device corresponding to the letter box area to have a luminance of about 30% do. As a result, the luminance of the light emitting device corresponding to the letter box is about 30% and off when the average luminance value of the image region is lower than the reference value.

Accordingly, in the case of displaying a moving picture on the liquid crystal display panel 100, the present invention controls the luminance of the light emitting device corresponding to the letter box area, which is a black margin at the upper and lower ends of the liquid crystal display panel 100 , The power consumption can be reduced in the letter box area as compared with the conventional case of generating light having a uniform luminance as in the other areas.

FIG. 3 is a schematic view of the liquid crystal display panel and the light emitting diode array of FIG. 1. FIG.

1 and 3, the light emitting diode array 140 includes a light emitting diode 143 for emitting light, and a light emitting diode 143 mounted on the light emitting diode 143 and electrically connected to the light emitting diode 143, And a printed circuit board 141 on which patterns for providing a driving signal to the light emitting diode 143 are formed.

When a moving image is displayed on the liquid crystal display panel 100, the liquid crystal display panel 100 displays a portion A where the image is displayed and a letter box of a black margin for matching the image ratio, ) Region (B). If the moving picture displayed on the liquid crystal display panel 100 is data corresponding to the Academy Standard standard, the ratio of the letter box area B is about 4.52%. Therefore, a letter box area B is displayed at the top / bottom of the liquid crystal display panel 100 at a ratio of 4.52% of the entire screen.

The light emitting diode 143 of the light emitting diode array 140 corresponding to the letter box region B of the liquid crystal display panel 100 is turned off or a portion And is turned on in a state in which the luminance is lower than the luminance.

When the moving picture is displayed on the liquid crystal display panel 100, the luminance of the light emitting device corresponding to the letter box area B, which is the black margin of the upper / lower end of the liquid crystal display panel 100, Compared to the conventional case in which light having a uniform luminance is generated in the letter box region B as in the other regions by lowering the luminance of the displayed portion A or turning off the luminance of the displayed portion A, Power can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view illustrating a liquid crystal display device according to an embodiment of the present invention. FIG.

2 is a detailed view of the letterbox area luminance controller of FIG. 1;

Fig. 3 is a schematic view of the liquid crystal display panel and the light emitting diode array of Fig. 1; Fig.

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

100: liquid crystal display panel 110: gate driver

120: Data driver 130: Timing controller

140: light emitting diode array 141: printed circuit board

143: Light emitting diode 150: Optical sheets

160: Letter box area luminance controller 161: Image data analyzer

163: Letter box area conversion unit 165: Image area average luminance analysis unit

167: comparator 169: letterbox luminance control signal generator

170: Backlight driver

Claims (6)

A liquid crystal display panel in which a plurality of gate lines and a plurality of data lines are arranged and displays an image; A gate driver for supplying a scan signal to the gate line; A data driver for supplying data to the data line; A light emitting diode array for emitting light to the liquid crystal display panel; The image data to be input to the liquid crystal display panel is analyzed to calculate a letter box area which is a black margin appearing at the upper and lower ends of the liquid crystal display panel of the image data, A letterbox area luminance controller for generating a control signal for controlling the luminance of the corresponding light emitting diode array; And A backlight driver for driving the light emitting diodes included in the light emitting diode array and for driving light emitting diodes corresponding to a letter box area of the liquid crystal display panel according to a control signal provided from the letter box area luminance controller; Including, Wherein the letterbox area luminance controller comprises: An image data analyzing unit that receives image data to be input to the liquid crystal display panel and analyzes image data according to a standard standard; A letter box area conversion unit for converting a ratio of the letter box area in the liquid crystal display panel to a moving picture displayed on the liquid crystal display panel according to a result analyzed by the image data analysis unit; An image area average luminance analyzer for analyzing an average luminance of an image area excluding the letter box area; A comparator for comparing a result analyzed by the image area average luminance analyzer with a preset reference value and generating a comparison signal according to the comparison result; And And a letter box area luminance control signal generator for generating a luminance control signal for controlling the luminance of the light emitting diode corresponding to the converted letter box area according to the comparison signal and providing the luminance control signal to the backlight driving part, Wherein, Generating a comparison signal having a logic high when the average luminance of the image region is greater than the reference value and generating a comparison signal having a logic low when the average luminance of the image region is less than the reference value, Wherein the letter box area luminance control signal generator comprises: When a high logic comparison signal is supplied from the comparator, a luminance control signal having a PWM duty ratio of 30% is supplied to the backlight driver. When a low logic comparison signal is supplied from the comparator, And provides a brightness control signal of 0 to 30% to the backlight driver. delete The method according to claim 1, Wherein the standard is one of an Academy Standard standard and a Cinema Scope standard. delete The method according to claim 1, Wherein the backlight driver controls the brightness of the light emitting diode corresponding to the letter box area according to the brightness control signal provided from the letter box area brightness control signal generator. The method according to claim 1, Wherein the light emitting diodes included in the light emitting diode array are arranged in a vertical direction on one side of the liquid crystal display panel.

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