KR101461031B1 - Liquid crystal display device and method for driving the same - Google Patents

Abstract

The present invention relates to a liquid crystal display device and a method of driving the same that can improve the quality of an image by correcting the brightness of light sources, including a backlight unit having a plurality of light sources for providing light of different colors to a display panel; Controlling the plurality of light sources to turn on sequentially during the sensing / correcting period, controlling the light sources of the remaining colors to be turned off while the light sources of one color are on, and controlling the light sources to be turned on during the display period, ; A light sensing unit that sequentially senses light from the light sources for each color during the sensing / correcting period and generates a luminance signal for each color of the light sources for each color; And a controller for generating luminance signals for the respective light sources of respective colors based on the sensing signals of the respective colors from the light sensing unit during the sensing / correcting period, and supplying the luminance signals to the backlight driving unit, And a brightness correction unit for controlling the brightness of the light sources according to the brightness of the light source.

A liquid crystal display, a light sensing part, an LED, a luminance, a sequential driving part,

Description

[0001] The present invention relates to a liquid crystal display device and a method of driving the same,

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 driving method thereof that can improve the quality of an image by correcting the luminance of light sources.

A display device includes a light emitting display device such as a cathode ray tube, an organic electro-luminescence display, a plasma display (PDP), and a liquid crystal display, There is a light-receiving-type display device which can not generate light by itself and requires a separate light source.

A typical liquid crystal display device includes two display panels provided with field generating electrodes and a liquid crystal layer having a dielectric anisotropy therebetween. A voltage is applied to the field generating electrode to generate an electric field in the liquid crystal layer, and the intensity of the electric field is controlled by changing the voltage, thereby adjusting the transmittance of light passing through the liquid crystal layer to obtain a desired image. The light at this time may be an artificial light source or a natural light separately.

As a light source for a liquid crystal display device, a plurality of lamps are generally used. As a light source that transmits light evenly to the entire liquid crystal panel from the rear side of the liquid crystal panel, an external electrode fluorescent lamp (EEFL) A fluorescent lamp such as a cold cathode fluorescent lamp (CCFL) or a light emitting diode (LED) is used.

Since the liquid crystal display device which is a light-receiving type device displays a screen using the light emitted from the backlight, the quality of the visualized surface is determined according to the brightness of the backlight. There is a problem that a luminance deviation is caused due to factors such as nonuniformity. Such a luminance deviation phenomenon is a phenomenon that is common to all the light sources, and is a problem that deteriorates the image quality of the liquid crystal display device.

1 is a view showing a conventional light emitting diode.

The major advantage of the LED backlight for a liquid crystal display device which is actively under research and development is that as shown in FIG. 1, light emitted from red, green, and blue light emitting diodes r, g, And supplying the mixture to a liquid crystal display device to provide an optimal color tone desired by the user. However, in such a light emitting diode used as a backlight source, the light efficiency is drastically changed by heat. This causes a sensitive balance between the external environment of the liquid crystal display device and the internal heat source, resulting in the collapse of the color balance.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a liquid crystal display device capable of increasing the quality of an image by comparing color coordinates and luminance of light irradiated to a panel of a liquid crystal display device, A display device and a driving method thereof are provided.

According to an aspect of the present invention, there is provided a liquid crystal display comprising: a backlight unit having a plurality of light sources for providing light of different colors to a display panel; Controlling the plurality of light sources to turn on sequentially during the sensing / correcting period, controlling the light sources of the remaining colors to be turned off while the light sources of one color are on, and controlling the light sources to be turned on during the display period, ; A light sensing unit sequentially sensing the light from the light sources by the color during the sensing / correcting period and generating a luminance signal representing the luminance of each color of the light sources for each color; And a controller for generating luminance signals for the respective light sources of respective colors based on the sensing signals of the respective colors from the light sensing unit during the sensing / correcting period, and supplying the luminance signals to the backlight driving unit, And a brightness correction unit for controlling the brightness of the light sources according to the brightness of the light source.

According to an aspect of the present invention, there is provided a method of driving a liquid crystal display (LCD) device, comprising: a) preparing a plurality of light sources for emitting light of different colors to a display panel; Controlling the plurality of light sources to sequentially turn on for each color so that the light sources of the other colors are turned off while the light sources of one color are turned on; A step C for sequentially sensing light from a plurality of light sources driven in accordance with the step B by color and generating a luminance signal representing the luminance of the light sources for each color; And a step D for controlling the luminance of the light sources on the basis of the luminance signal for each color from the step (C).

The liquid crystal display device and the driving method thereof according to the present invention have the following effects.

First, uniform white light can be emitted by comparing and correcting the luminance of the light sources with the predetermined reference luminance signal every predetermined period, thereby improving the quality of the image.

Second, since the lighting time of the light sources emitting light of different colors is controlled for each color, the luminance information of the light sources of different colors can be grasped by one light sensing unit, thereby reducing the manufacturing cost of the liquid crystal display device .

Thirdly, by forming the light sensing part on the TFT array substrate simultaneously with the thin film transistor, a liquid crystal display device can be manufactured without increasing process time and cost.

FIG. 2 is a view illustrating a liquid crystal display device according to an embodiment of the present invention, and FIG. 3 is a view illustrating a backlight unit of FIG. 2. Referring to FIG.

2, the liquid crystal display according to the embodiment of the present invention includes gate lines GL and data lines DL intersecting with each other, and gate lines GL and data lines DL, A display panel 100 including a thin film transistor (TFT) formed at an intersection between a plurality of display pixels DL; A data driver DD for inputting data to the data lines DL of the display panel 100 and a gate driver GD for inputting a scan pulse to the gate lines GL of the display panel 100. [ A backlight unit 300 for driving the light sources r, g, and b provided in the backlight unit 200, a backlight unit 300 for driving the backlight unit 200, A light sensing unit 111 for sensing light from the light sources r, g and b and a light sensing unit SS1 for sensing light SS1, SS2 and SS3 from the light sensing unit 111, a luminance correction unit 400 for generating luminance signals BS1, BS2 and BS3 for correcting the luminance of the display panel 100, r, g and b and supplying the luminance signals BS1, BS2 and BS3 to the backlight driving unit 300, A timing controller TC for controlling the data driver DD, the gate driver GD and the backlight driver 300 of the display panel 100, The power required for this teubu 200, and a power generating unit (PW) for supplying.

The thin film transistor TFT formed at the intersection of the data lines DL and the gate lines GL of the display panel 100 receives data on the data lines DL in response to a scanning pulse from the gate driver GD. To the liquid crystal cell. The source electrode of the thin film transistor TFT is connected to the data line DL, and the drain electrode is connected to the pixel electrode of the liquid crystal cell. The gate electrode of the thin film transistor TFT is connected to the gate line GL. The display panel 100 includes a color filter array substrate and a TFT array substrate bonded together with a liquid crystal layer interposed therebetween. A color filter and a common electrode are formed on the color filter array substrate. The color filters allow red, green, and blue color filter layers to be disposed to transmit light in a specific wavelength band, thereby enabling color display. A black matrix is formed between color filters of adjacent colors.

Each liquid crystal cell includes a liquid crystal capacitance capacitor Clc for holding data for one frame period and an auxiliary capacitance capacitor for stably maintaining the data for the frame period.

The timing controller TC rearranges the digital video data input from the digital video card into red data R, green data G and blue data B. The data (R, G, B) rearranged by the timing controller (TC) is input to the data driver (DD).

The timing controller TC generates the data control signal DCS and the gate control signal GCS using the horizontal synchronizing signal Hsync, the vertical synchronizing signal Vsync and the clock signal CLK input to the timing controller TC And supplies it to the data driver DD and the gate driver GD. The data control signal DCS includes a dot clock, a source shift clock, a source enable signal, a polarity reversal signal, and the like. The gate control signal GCS is input to the gate driver GD including a gate start pulse, a gate shift clock, a gate output enable, and the like.

The data driver DD samples the data in accordance with the data control signal DCS from the timing controller TC and then latches the sampled data by one line for each horizontal period (1H, 2H, 2H) And supplies data to the data lines DL. That is, the data driver DD converts the data (R, G, B) from the timing controller TC into analog pixel signals using the gamma voltages GMA1-6 input from the power generating unit PW And supplies them to the data lines DL.

The gate driver GD includes a shift register for sequentially generating scan pulses in response to a gate start pulse of a gate control signal GCS from the timing controller TC and a control circuit for controlling the voltage of the scan pulse to a voltage level suitable for driving the liquid crystal cell And a level shifter. The gate driver GD sequentially supplies a gate high voltage to the gate lines GL in response to the gate control signal GCS.

The power supply PW supplies the common electrode voltage Vcom to the display panel 100, the gamma voltages GMA1 to GMA6 to the data driver DD, and the lamp driving voltage Vinv to the backlight driver 300. [

Hereinafter, the backlight unit 200, the light sensing unit 111, the backlight driving unit 300, and the luminance correction unit 400 will be described in more detail.

FIG. 3 is a view illustrating light sources provided in the backlight unit 200 of FIG. 2. FIG. 4 is a view for explaining an operation of the backlight driver 300 of FIG.

The backlight unit 200 includes a plurality of light sources r, g, and b as shown in FIG. The plurality of light sources r, g, and b are light emitting diodes (LEDs), a plurality of red light sources r for emitting red light, green light sources g for emitting green light, , And blue light sources (g) for emitting blue light. White light is produced by combining the red light from the red light sources r, the green light from the green light sources g, and the blue light from the blue light sources g.

The red light sources r, the green light sources g, and the blue light sources g are all light emitting diodes (LEDs).

The backlight driver 300 includes a sensing / correction period for sensing the light from the light sources r, g and b to correct the luminance of the light sources r, g and b, And operates differently in the display period in which light is supplied to the display panel 100.

That is, the backlight driver 300 controls the plurality of light sources r, g, b to turn on sequentially for each color during the sensing / correcting period, while the light sources of any color are turned on Off. On the other hand, the backlight driver 300 simultaneously lights all of the light sources r, g, and b during the display period, and maintains the lighted state for the display period. For this, the backlight driver 300 controls the plurality of light sources r, g, and b to be sequentially turned on for each color during the sensing / correcting period, while the light sources of one color are turned on And a simultaneous driving unit Drv2 for controlling the light sources r, g and b to be turned on during the display period.

For example, when the light sources r, g, and b are composed of the three color light sources r, g, and b described above, the backlight driver 300, During the calibration period, the red light sources r are driven first, the green light sources g are driven the second time, and the blue light sources g are driven the third time. The driving order of the light sources r, g, and b may be changed.

4, the backlight driving unit 300 maintains the light sources r, g, and b in a turned-on state regardless of their colors during the display period.

The light sensing unit 111 sequentially senses light from the light sources r, g, and b by color during the sensing / correcting period and sequentially outputs the luminance of each of the light sources r, g, (SS1, SS2, SS3) for each color. For example, the light sensing unit 111 senses red light from red light sources r that are first driven within the sensing / correcting period, and generates a first sensing signal SS1 for the red light. A second sensing signal SS2 for the green light by sensing green light from the second green light sources g in the sensing / correcting period; And generates a third sensing signal SS3 for the blue light by sensing blue light from the blue light sources g that are driven for the third time in the sensing / correcting period. The light sensing unit 111 may be a mono photo sensor or an illumination sensor having no separate color filter for recognizing the light wavelength from the light sources r, g, and b.

As described above, in the present invention, the lighting time of the light sources r, g, and b is controlled for each color, so that the brightness information for the light sources r, g, You can find out.

The luminance corrector 400 corrects the luminance of the light sources r, g, and b on a color-by-color basis based on the sensing signals of the respective colors from the light sensing unit 111 during the sensing / correcting period. By providing the corrected values to the backlight driver 300, the backlight driver 300 can control the brightness of the light sources according to the corrected values during the display period.

The liquid crystal display according to the present invention further includes a control signal generator 500 for setting the operation period of the sequential driver Drv1 and the simultaneous driver Drv2.

5 is a diagram showing a control signal generator 500 for generating a drive control signal CS for controlling the operations of the sequential drive Drv1 and the simultaneous drive Drv2, And a vertical synchronization signal Vsync used to generate the drive control signal CS.

The control signal generator 500 generates the drive control signal CS using the vertical synchronization signal Vsync from the timing controller TC as shown in Fig.

The vertical synchronization signal Vsync has a plurality of high intervals and a plurality of low intervals as a signal having a period of one frame period, as shown in Fig. The row section of the vertical synchronization signal Vsync indicates a blank section in which no data is output. The high period of the vertical synchronization signal Vsync indicates a period of time when an image is displayed on the screen of the display unit, and has a much wider length than the blank period.

The control signal generator 500 counts the number of blank intervals of the vertical synchronization signal Vsync by a predetermined number by using a counter so that whenever the counted number reaches the set number, And sets a low period of the driving control signal CS by outputting a low logic value during the counting period. Thereby, a drive control signal CS having a period of several frames as shown in Fig. 5 is generated. FIG. 5 shows an example of a drive control signal CS having one high logic value per three blank periods. Each high period of the driving control signal CS has a length corresponding to the blank period and each low period of the driving control signal CS has a length corresponding to several frame periods. In FIG. 5, each of the high periods is set to a period corresponding to about three frame periods, but it is preferable to set a period corresponding to about several hundreds to several thousand frame periods.

The period corresponding to each high section of the drive control signal CS is the sensing / correction period described above, and the period corresponding to each low section of the drive control signal CS is the display period described above.

The control signal generator 500 supplies the driving control signal CS to the sequential driving unit Drv1 and the simultaneous driving unit Drv2. The sequential driver Drv1 operates during a period corresponding to a high period of the driving control signal CS and does not operate during a period corresponding to a low period of the driving control signal CS. Conversely, the simultaneous driving unit Drv2 operates during a period corresponding to a low period of the driving control signal CS and does not operate during a period corresponding to a high period of the driving control signal CS. In other words, the sequential driver Drv1 sequentially turns on the light sources r, g and b of the backlight unit 200 when the drive control signal CS has a high logic value, (Drv2) keeps all the light sources (r, g, b) of the backlight unit 200 in a lighted state when the drive control signal CS has a low logic value. The sequential driving unit Drv1 outputs a plurality of lighting control signals LS1, LS2 and LS3 in response to the driving control signal CS and the simultaneous driving unit Drv2 generates a plurality of driving signals DS1 , DS2, and DS3.

7 is a diagram showing a timing chart between the drive control signal CS, the lighting control signal, and the drive signal.

The sequential driving unit Drv1 generates a plurality of lighting control signals LS1, LS2 and LS3 during the sensing / correction period in which the driving control signal CS has a high logic value, and sequentially outputs them. That is, as shown in FIG. 7, the sequential driver Drv1 generates and outputs first to third turn-on control signals LS1, LS2, LS3 having phase differences with each other during the sensing / correcting period. For example, the first turn-on control signal LS1 is output first within the sensing / correcting period, the second turn-on control signal LS2 is output secondly within the sensing / correcting period, And the third lighting control signal LS3 is output for the third time within the sensing / correcting period.

The first turn-on control signal LS1 is a signal for driving the red light sources r, the second turn-on control signal LS2 is a signal for turning on the green light sources g, LS3 are control signals for turning on the blue light sources g.

Accordingly, during the sensing / correcting period, the red light sources r are firstly turned on, the green light sources g are turned on secondly, and the blue light sources g are turned on thirdly.

The simultaneous drive unit Drv2 generates a plurality of drive signals DS1, DS2 and DS3 during the display period in which the drive control signal CS has a low logical value and outputs the drive signals DS1, DS2, And supplies them to the light sources r, g, and b at the same time. That is, the simultaneous driving unit Drv2 supplies the first driving signal DS1 to the red light sources r, the second driving signal DS2 to the green light sources g, (DS3) to the blue light sources (g).

Since the red light source r, the green light source g and the blue light source g emit light of different wavelengths, different light from the light sources r, g and b is combined to emit white light The amplitude of the second driving signal DS2 for driving the green light source g must be the largest among the first to third driving signals DS1, DS2, and DS3. The amplitude of the third driving signal DS3 for driving the blue light source g should be the smallest among the first to third driving signals DS1, DS2 and DS3. The amplitude of the first driving signal DS1 for driving the red light source r should be smaller than the amplitude of the second driving signal DS2 and larger than the amplitude of the third driving signal DS3. However, the duty ratios of the first to third driving signals DS1, DS2, and DS3 output during the display period are all the same. The initial duty ratio of the first to third driving signals DS1, DS2, and DS3 is set to about 80%. Similarly to the first to third drive signals DS1, DS2 and DS3, the first to third turn-on control signals LS1, LS2 and LS3 have different amplitudes.

The first to third turn-on control signals LS1, LS2, and LS3 output from the sequential driver Drv1 are also supplied to the brightness corrector 400 to control the brightness corrector 400. [ The brightness correction unit 400 sequentially receives detection signals of the respective colors from the light sensing unit 111 according to the first to third turn-on control signals LS1, LS2, and LS3.

2, the brightness correction unit 400 includes an input control unit 401, a brightness adjustment unit 402, and a memory unit 403.

The input control unit 401 receives the sensing signals SS1, SS2, and SS3 from the light sensing unit 111 according to the first to third lighting control signals LS1, LS2, and LS3 from the sequential driving unit Drv1, ) Sequentially, and sequentially outputs them. The brightness adjusting unit 402 corrects the sensing signals SS1, SS2, and SS3 for each color from the input controller 401 using a preset reference brightness signal. The calibrated sensing signal is a luminance signal, and the memory unit 403 stores a luminance signal for each color from the luminance controller 402,

8 is a detailed configuration diagram of the input controller 401 and the luminance controller 402 of FIG.

The input control unit 401 includes first to third switching elements SW1, SW2, and SW3 as shown in FIG.

The first switching device SW1 outputs a first sensing signal SS1 from the light sensing unit 111 according to a first lighting control signal LS1. That is, the first switching device SW1 is turned on for a period corresponding to a high section of the first lighting control signal LS1, and is turned on during a period corresponding to a low section of the first lighting control signal LS1 And maintains the turn-off state. The first switching device SW1 supplies a first sensing signal SS1 from the turn-on light sensing unit 111 to the luminance correction unit 400. [

The second switching device SW2 outputs the second sensing signal SS2 from the light sensing unit 111 according to the second lighting control signal LS2. That is, the second switching device SW2 is turned on during a period corresponding to a high section of the second turn-on control signal LS2, and during a period corresponding to a low section of the second turn-on control signal LS2 And maintains the turn-off state. The second switching device SW2 supplies a second sensing signal SS2 from the turn-on light sensing unit 111 to the luminance correction unit 400. [

The third switching device SW3 outputs the third sensing signal SS3 from the light sensing unit 111 according to the third lighting control signal LS3. That is, the third switching device SW3 is turned on during a period corresponding to the high section of the third turn-on control signal LS3 and during a period corresponding to the low section of the third turn-on control signal LS3 And maintains the turn-off state. The third switching device SW3 supplies the third sensing signal SS3 from the turn-on light sensing unit 111 to the luminance correction unit 400. [

The first through third switching elements SW1, SW2 and SW3 are controlled by the sequential driving part Drv1 so that the switching elements SW1, SW2 and SW3 are also sequentially Turn on. That is, the first switching device SW1 is turned on first, the second switching device SW2 is turned on second time, and the third switching device SW3 is turned on, Is turned on for the third time. At this time, when any one of the first to third switching elements SW1, SW2, and SW3 is in the turn-on state, the remaining switching elements maintain the turn-off state.

In other words, as the first to third turn-on control signals LS1, LS2, and LS3 are sequentially output from the sequential driver Drv1, the first to third switching elements SW1, SW2, and SW3 And are sequentially turned on in synchronization with the lighting sequence of the light sources r, g, and b. That is, a period during which the red light source r is lit and a period during which the first switching device SW1 is turned on are synchronized with each other, and a period during which the green light source g is lit and a period during which the second switching device And the period during which the blue light source g is turned on and the period during which the third switching device SW3 is turned on are synchronized with each other.

The first through third sensing signals SS1, SS2 and SS3 sequentially outputted from the respective switching elements SW1, SW2 and SW3 are supplied to the luminance corrector 400. [ 8, the luminance corrector 400 includes a red luminance controller 411, a green luminance controller 412, and a blue luminance controller 413.

The red luminance controller 411 corrects the first sensing signal SS1 from the first switching element SW1 using a first reference luminance signal set in advance. The green luminance controller 412 corrects the second sensing signal SS2 from the second switching element SW2 using a second reference luminance signal set in advance. The blue brightness adjusting unit 413 corrects the third sensing signal SS3 from the third switching device SW3 using a third reference brightness signal that is set in advance.

Here, the red luminance adjustment unit 411, the green luminance adjustment unit 412, the blue luminance adjustment unit 413, and the memory unit 403 will be described in more detail.

9 is a detailed configuration diagram of the red luminance adjustment unit 411, the green luminance adjustment unit 412, the blue luminance adjustment unit 413, and the memory unit 403 in FIG.

The red luminance adjustment unit 411, the green luminance adjustment unit 412 and the blue luminance adjustment unit 413 are connected to the reference signal generation units 425, 525 and 625, the amplification units 421, 521 and 621, Digital converters 422, 522 and 622, comparators 423, 523 and 623, and adders 424, 524 and 624, respectively.

Specifically, the red reference signal generator 425 provided in the red brightness controller 411 outputs the preset first reference brightness signal Vref_r to the comparator 423 and the adder 424 . The amplifying unit 421 amplifies the first sensing signal SS1 from the first switching device SW1. The analog-to-digital converter 422 converts the amplified first sensing signal SS1 from the amplifier 421 into a digital signal. The comparator 423 compares the magnitude between the first sensing signal SS1 from the analog-to-digital converter 422 and the first reference luminance signal Vref_r from the red reference signal generator 425, A correction value indicating the difference between the two values is calculated. The adder 424 adds the correction value to the first reference luminance signal Vref_r to generate the first luminance signal BS1. The correction value may have a positive value or a negative value according to the comparison result.

The green reference signal generator 525 provided in the green brightness controller 412 outputs a preset second reference brightness signal Vref_g and supplies the second reference brightness signal Vref_g to the comparator 523 and the adder 524. The amplifying unit 521 amplifies the second sensing signal SS2 from the second switching device SW2. The analog-to-digital converter 522 converts the amplified second sensing signal from the amplifier 521 into a digital signal. The comparator 523 compares the magnitude between the second sensing signal SS2 from the analog-to-digital converter 522 and the second reference luminance signal Vref_g from the green reference signal generator 525, A correction value indicating the difference between the two values is calculated. The adder 524 adds the correction value to the second reference luminance signal Vref_g to generate a second luminance signal BS2. The correction value may have a positive value or a negative value according to the comparison result.

The blue reference signal generator 625 provided in the blue brightness controller 413 outputs the preset third reference brightness signal Vref_b to the comparator 625 and the adder 624. The amplifying unit 621 amplifies the third sensing signal SS3 from the third switching device SW3. The analog-to-digital converter 622 converts the amplified third sensing signal SS3 from the amplifier 621 into a digital signal. The comparator 623 compares the magnitude between the third sensing signal SS3 from the analog-to-digital converter 622 and the third reference luminance signal Vref_b from the blue reference signal generator 625, A correction value indicating the difference between the two values is calculated. The adder 624 adds the correction value to the imaginary third reference luminance signal Vref_b to generate the third luminance signal BS3. The correction value may have a positive value or a negative value according to the comparison result.

The first to third reference luminance signals Vref_r, Vref_g and Vref_b are compared with the first to third sensing signals SS1, SS2 and SS3 to control the luminance of the light sources r, g and b These first to third reference luminance signals Vref_r, Vref_g and Vref_b have a constant value as long as there is no adjustment from the outside.

The memory unit 403 includes first to third memories MR1, MR2 and MR3, as shown in Fig.

The first memory MR1 stores the first luminance signal BS1 from the adder 424 provided in the red luminance controller 411. [ The second memory MR2 stores the second luminance signal BS2 from the adder 524 provided in the green luminance controller 412. [ The third memory MR3 stores the third luminance signal BS3 from the adder 624 provided in the blue luminance controller 413. [ The first reference brightness signal Vref_r is previously stored in the first memory MR1 for the initial driving of the light sources r, g and b before the brightness signals BS1, BS2 and BS3 are stored. A second reference brightness signal Vref_g is previously stored in the second memory MR2 and a third reference brightness signal Vref_b is stored in advance in the third memory MR3.

As described above, during one sensing / correcting period, the sequential driver Drv1 is operated by the drive control signal CS having the high logic value, and the sequential driver Drv1 causes the light sources r the first to third switching elements SW1, SW2 and SW3 are sequentially turned on according to the color, and the sensing signals for respective colors (for example, SS1, SS2, and SS3 may be sequentially corrected and sequentially stored in the first to third memories MR1, MR2, and MR3.

Thereafter, the display period begins immediately after the completion of the sensing / correcting period. During this display period, the simultaneous driver Drv2 starts operating by the drive control signal CS having a low logic value. The simultaneous driver Drv2 generates the first driving signal DS1 based on the first luminance signal BS1 stored in the first memory MR1 and outputs the second luminance signal BS2 stored in the second memory MR2, Generates the second driving signal DS2 based on the signal BS2 and generates the third driving signal DS3 based on the third luminance signal BS3 stored in the third memory MR3.

Specifically, the simultaneous driving unit Drv2 generates the above-described first to third driving signals DS1, DS2 and DS3 by modulating the pulse width of each luminance signal. To this end, the simultaneous drive unit Drv2 may include a pulse width modulation unit.

The first to third driving signals DS1, DS2 and DS3 from the simultaneous driving unit Drv2 are simultaneously supplied to the light sources r, g and b. That is, the first driving signal DS1 is supplied to the red light sources r, the second driving signal DS2 is supplied to the green light sources g, and the third driving signal DS3 is supplied to the blue light source Are supplied to the circles g. Accordingly, all of the light sources r, g, and b remain lit during the display period irrespective of colors.

As the light sources r, g, and b are all kept on during the display period, the display panel 100 is supplied with white light. Of course, the white light is also supplied to the light sensing unit 111. The light sensing unit 111 operates to output the sensing signals SS1, SS2 and SS3. During this display period, the sequential driving unit Drv1 is not operated and all the switching elements of the input control unit 401 The sensing signals SS1, SS2, and SS3 from the light sensing unit 111 can not be supplied to the brightness controller 402 because the switches SW1, SW2, and SW3 are maintained in the turn-off state. Accordingly, there is no risk that the luminance signals stored in the memories MR1, MR2, and MR3 are changed by the white light during the display period.

At the end of this display period, a second sense / correction period starts. During the second sensing / correcting period, the first to third turn-on control signals LS1, LS2 and LS3 are outputted again as the sequential driver Drv1 operates again. At this time, the sequential driving unit Drv1 controls the first to third lighting controls BS1, BS2 and BS3 based on the first to third luminance signals BS1, BS2 and BS3 stored in the first to third memories MR1, MR2 and MR3. And outputs signals LS1, LS2, and LS3. Therefore, the first to third turn-on control signals LS1, LS2 and LS3 outputted in the second sensing / correcting period are the same as the first to third driving signals DS1, DS2 and DS3 outputted during the above- Pulse width. This is because the first to third turn-on control signals LS1, LS2 and LS3 and the first to third drive signals DS1, DS2 and DS3 are both the first to third And is a signal generated based on the luminance signals BS1, BS2, and BS3.

In other words, the first to third luminance signals BS1, BS2 and BS3 generated in the (k-1) th sensing / correcting period (k is a natural number of 2 or more) And is a signal necessary to output the signals DS1, DS2, and DS3. The first through third brightness signals BS1, BS2 and BS3 generated in the (k-1) th sensing / correcting period are supplied to the first through third lighting control signals LS1, LS2 and LS3 ).

Meanwhile, a black image may be displayed on the front face of the display portion of the display panel 100 to prevent an unnecessary light source from the outside from being incident on the sensing portion during the sensing / correcting period. Thus, the reliability of the light sensing unit 111 can be improved.

Figs. 10 and 11 are diagrams showing waveforms of a scan pulse outputted for displaying a black image on the display panel 100. Fig.

The scan pulses sequentially output from the gate driver GD are sequentially supplied to the gate lines GL of the display panel 100. [ One scan pulse (SP1 to SPn) is supplied to each gate line GL every frame period. In other words, as shown in FIG. 10, the scan pulses SP1 to SPn are sequentially output in the display period. In this display period, data is output from the data driver DD in synchronization with the scan pulses SP1 to SPn and supplied to the data lines DL.

 As shown in FIG. 10, during the sensing / correction period, the scan pulses SP1 to SPn are simultaneously output and all the scan pulses And simultaneously supplied to the lines GL. In this detection / correction period, black data for displaying black from the data driver DD is supplied to the data lines DL in synchronization with the respective scan pulses SP1 to SPn. Accordingly, a black image is displayed on the entire display portion of the display panel 100 during the sensing / correcting period.

As another example, the scan pulses SP1 to SPn may be sequentially output during the sensing / correction period, as shown in FIG. During the detection / correction period, the scan pulses SP1 to SPn are sequentially output and sequentially supplied to the gate lines GL. In this detection / correction period, black data for displaying black from the data driver DD is supplied to the data lines DL in synchronization with the respective scan pulses SP1 to SPn. At this time, as the gate lines GL are sequentially driven in the sensing / correcting period, the entire display unit of the display panel 100 displays a black image in units of one horizontal line. Of course, a black image is displayed on the entire display portion of the display panel 100 at the moment when the last gate line GL is driven. At this time, since the time for which the sensing / correcting period is maintained is short, the pulse width of each of the scan pulses SP1 to SPn must be reduced. Therefore, the amplitude of the scan pulses SP1 to SPn in the sensing / Period of the scan pulses SP1 to SPn.

In order to display a black image on the entire display portion every detection / correction period, the timing controller TC has a function of inserting black data between each data and a function of inserting the black data into the black It should have more functionality to align data and data properly. The timing controller TC may be configured to allow the gate driver GD to output scan pulses SP1 to SPn during the sensing / (GD) and the data driver (DD) by further including a separate control signal for controlling data output to the gate control signal (GCS) and the data control signal (DCS) do.

Meanwhile, the first to third turn-on control signals LS1, LS2, and LS3 may be sequentially output during a plurality of sensing / correcting periods.

12 is a diagram showing another waveform diagram of the first to third turn-on control signals LS3.

As shown in FIG. 12, the first turn-on control signal LS1 has a high logic value during the first sensing / correction period of the three adjacent sensing / correction periods, and a low logic value during each display period . The second turn-on control signal LS2 has a high logic value during the second sensing / correcting period and a low logic value during each display period. The third turn-on control signal LS3 has a high logic value during the third sensing / correcting period and a low logic value during each display period.

In order to sequentially output the first to third turn-on control signals LS1, LS2 and LS3 during the adjacent sense / correction period, the control signal generator 500 generates the turn-on control signals LS1, LS2 and LS3 ) Of the number of counters. At this time, each counter is set to count different numbers.

That is, the control signal generator 500 counts the number of blank intervals of the vertical synchronization signal (Vsync) by a predetermined number using the first counter so that the high-logic Value to set the high period of the drive control signal CS and outputs a low logic value during the counting period to set the low period of the drive control signal CS.

The control signal generator 500 counts the number of blank intervals of the vertical synchronization signal Vsync by a predetermined number using the second counter so that a high logic value is obtained every time the counted number reaches the set number Sets a high period of the drive control signal CS and outputs a low logic value during the counting period to set a low period of the drive control signal CS.

The control signal generator 500 counts the number of blank intervals of the vertical synchronizing signal Vsync by a predetermined number using a third counter so that the counted number reaches a high logic value And outputs a low logic value during the counting period to set a low period of the driving control signal CS.

12 shows drive control signals CS generated by combining the outputs from the first to third counters.

As shown in FIG. 12, the drive control signal CS is held at a high logic value during three sensing / correction periods adjacent to each other, and then held at a low logic value until the next three sensing / correction periods start. Also, the driving control signal CS is maintained at a low logic value during the period between adjacent sensing / correction periods.

The first to third driving signals DS1, DS2 and DS3 have a low logic value during the sensing / correction period and repeatedly have a high logic value and a low logic value during the display period. The duty ratios of the first to third driving signals DS1, DS2, and DS3 output during the display period are all the same.

The display period between the three sensing / correcting periods adjacent to each other may be any frame period, but it is preferable not to exceed one frame period. The period between the first detection / correction period and the second detection / correction period in FIG. 12 corresponds to one frame period, and the display period between the second detection / correction period and the third detection / correction period also corresponds to one frame period . However, the display period between the first detection / correction period and the third detection / correction period and the display period between the third detection / correction period and the first detection / correction period are set to several hundred frame periods It is good to do.

When the first to third turn-on control signals LS1, LS2 and LS3 and the first to third drive signals DS1, DS2 and DS3 are used as shown in Fig. 12, the sequential drive unit Drv1 ) Operates as follows.

That is, the sequential driver Drv1 outputs the first lighting control signal LS1 to the red light sources r at the kth sensing / correcting period (k is a natural number), and supplies the first lighting control signal LS1 to the first switching device SW1 . Accordingly, only the red light sources r are turned on during the kth sensing / correcting period. Accordingly, the first luminance signal BS1 is output from the red luminance controller 411 during the kth sensing / correcting period. The first luminance signal BS1 is stored in the first memory MR1.

Then, in the k-th display period, the coincidence driving unit Drv2 receives the first luminance signal BS1 from the first memory MR1, the second reference luminance signal Vref_g from the second memory MR2, And drives the light sources r, g, b according to the third reference luminance signal Vref_b from the memory MR3.

Next, only the green light sources g are turned on during the (k + 2) th sensing / correcting period. Accordingly, the second luminance signal BS2 is output from the green luminance controller 412 during the (k + 2) th sensing / correcting period. The second luminance signal BS2 is stored in the second memory MR2.

Then, in the (k + 2) th display period, the simultaneous driver Drv2 receives the first luminance signal BS1 from the first memory MR1, the second luminance signal BS2 from the second memory MR2, 3 drives the light sources r, g, and b in accordance with the third reference luminance signal Vref_b from the third memory MR3.

Next, only the blue light sources g are lighted in the (k + 3) th sensing / correcting period. Accordingly, the third luminance signal BS3 is output from the blue luminance controller 413 during the (k + 3) th sensing / correcting period. The third luminance signal BS3 is stored in the third memory MR3.

Then, in the (k + 3) th display period, the coincidence driving unit Drv2 outputs the first luminance signal BS1 from the first memory MR1, the second luminance signal BS2 from the second memory MR2, And drives the light sources r, g, and b according to the third luminance signal BS3 from the third memory MR3.

That is, the (k + 3) -th display period is a period having a length of several hundred frame periods, from which red light sources r, green light sources g, and blue light sources g all emit light .

The detection / correction period may be set to the length of one frame rather than the length of the blank period.

13 is a diagram showing waveforms of various signals in a sensing / correction period having a length of one frame period.

As shown in FIG. 13, the control signal CS is maintained at a high logic value during each sensing / correction period corresponding to one frame period, and maintained at a low logic value during each display period corresponding to several hundred frame periods.

The first to third turn-on control signals LS1, LS2 and LS3 have a high logic value during each sensing / correction period and a low logic value during each display period. The first to third turn-on control signals LS1, LS2, and LS3 may sequentially have a high logic value during one sensing / correcting period, and may also have a high logic value during one sensing / It can also have a high logic value every time.

The first to third driving signals DS1, DS2 and DS3 have a low logic value during each sensing / correcting period and repeatedly have a high logic value and a low logic value during the display period. The duty ratios of the first to third driving signals DS1, DS2, and DS3 output during the display period are all the same.

The display period preferably has a length of several hundred frame periods.

In order to display a black image on the display unit in each sensing / correcting period, the scan pulses SP1 to SPn may be output simultaneously or sequentially in the sensing / correction period of the frame. During each sensing / correction period, black data (BD) is supplied from the data driver (DD) to the display unit.

The light sensing part 111 in the present invention may be formed in a liquid crystal margin area of the display panel 100.

FIG. 14 is a view for explaining the position of the light sensing part 111 in the display panel 100. FIG.

The display panel 100 includes a color filter array substrate 102 and a TFT array substrate 101 which are bonded to each other with a liquid crystal layer interposed therebetween, as shown in Fig. The TFT array substrate 101 has a display portion 999 for displaying an image. The display portion 999 includes an effective display region 911 and a liquid crystal margin region 910. The liquid crystal margin area 910 surrounds the effective display area 911 as an area filled with extra liquid crystal.

The light sensing unit 111 may be formed in the liquid crystal margin region 910. In addition, the light sensing portion 111 may be formed on the TFT array substrate 101 so as to be covered by the black matrix of the color filter array substrate 102.

15 is a view for explaining another position of the light sensing part 111 in the display panel 100. As shown in FIG.

As shown in FIG. 15, the display panel is connected to a data printed circuit board (PCB) through a plurality of data TCPs (Tape Carrier Packages). A data driver IC (D-IC) is mounted on each of the data TCPs.

The data driver IC (D-IC) receives various signals from a driving circuit mounted on the data PCB, and supplies data to the data lines of the display panel 100. At this time, the data lines are connected to the data driver ICs (D-ICs) through a plurality of link lines (LK).

The link lines LK have a shape radially spread out from each data driver IC (D-IC). At this time, an inverted triangular space is formed between the link lines LK connected to the adjacent data driver ICs (D-ICs), and the light sensing part 111 may be formed in this space.

Since this space does not form the link line LK, it generates a step with the portion where the link lines LK are formed. However, as in the present invention, the step may be removed by forming a light sensing part 111 having an inverted triangular shape capable of filling the space in the space. By eliminating the stepped portion, it is possible to solve problems caused by the polyimide rubbing process.

16 is a diagram showing a structure of the light sensing unit 111 according to the first embodiment and a circuit symbol corresponding thereto.

16A, the photodetector 111 includes a gate insulating film GI formed on the TFT array substrate 101 and a gate insulating film G1 formed on the gate insulating film GI, first and second ohmic contact layers 851 and 852 formed on both side edges of the semiconductor layer 801 and a second ohmic contact layer 852 formed on the first ohmic contact layer 851 A source electrode SE formed on the second ohmic contact layer 852 and a protection film formed on the entire surface of the TFT array substrate 101 including the drain and source electrodes DE and SE, (888).

Such a light sensing portion 111 can be represented by a switching element Tr1 without a gate electrode, as shown in Fig. 16 (b).

When the semiconductor layer 801 of the light sensing part 111 is irradiated with light from the light sources, the semiconductor layer 801 of the light sensing part 111 is excited and the drain electrode DE (Ic) is generated. The light sensing unit 111 supplies the light current Ic as a sensing signal to the luminance corrector 400.

17 is a diagram showing a structure of the light sensing unit 111 according to the second embodiment and corresponding circuit symbols.

17A, the light sensing part 111 includes a gate insulating film GI formed on the TFT array substrate 101 and a gate electrode GE formed on the gate insulating film GI. A semiconductor layer 801 formed on the gate insulating layer GI so as to overlap a part of the gate electrode GE and first and second ohmic contact layers A drain electrode DE formed on the first ohmic contact layer 851 and a source electrode SE formed on the second ohmic contact layer 852 and a source electrode SE formed on the drain and source electrodes 851 and 852, A source electrode SE and a protection film 882 exposed by the first contact hole C1 passing through the protection film 888. The protection film 888 is formed on the entire surface of the TFT array substrate 101, Which electrically connects the gate electrodes GE exposed by the second contact holes C2 that sequentially pass through the gate insulating film GI It includes an electrode (870). The connection electrode 870 is the same as the pixel electrode provided in the liquid crystal cell in the display portion 999.

The light sensing part 111 may be represented by a switching element Tr2 in which the gate electrode GE and the source electrode SE are connected to each other, as shown in FIG. 16 (b).

When the semiconductor layer 801 of the light sensing part 111 is irradiated with light from the light sources, the semiconductor layer 801 of the light sensing part 111 is excited and the drain electrode DE (Ic) is generated. The light sensing unit 111 supplies the light current Ic as a sensing signal to the luminance corrector 400.

The light sensing part 111 is formed at the same time when the thin film transistor TFT is manufactured because the light sensing part 111 is manufactured in the same process as the process of manufacturing the thin film transistor in the liquid crystal cell.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. Will be clear to those who have knowledge of.

1 is a view showing a conventional light emitting diode.

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

3 is a view showing the backlight unit of Fig. 2

4 is a view for explaining the operation of the backlight driving unit of FIG. 2;

5 shows a control signal generator for generating a drive control signal for controlling the operations of the sequential drive unit and the coincidence drive unit

6 is a diagram showing a drive control signal from the control signal generator of FIG. 5 and a vertical synchronization signal used to generate the drive control signal

7 is a timing chart showing the timing between the drive control signal, the lighting control signal, and the drive signal

8 is a detailed configuration diagram of the input controller and the luminance controller of FIG.

9 is a detailed configuration diagram of the red luminance adjustment unit, the green luminance adjustment unit, the blue luminance adjustment unit, and the memory unit of FIG. 8

Figs. 10 and 11 are diagrams showing waveforms of scan pulses outputted for displaying a black image on the display panel

12 is a diagram showing another waveform diagram of the first to third turn-on control signals

13 is a view showing waveforms of various signals in a sensing / correcting period having a length of one frame period

14 is a view for explaining the position of the light sensing part in the display panel

15 is a view for explaining another position of the light sensing portion in the display panel

16 is a view showing a structure of a light sensing unit according to the first embodiment and a circuit symbol corresponding thereto;

17 is a view showing the structure of the light sensing part according to the second embodiment and the corresponding circuit symbol

Description of the Related Art

GD: Gate driver DD: Data driver

TC: timing controller 100: display panel

200: backlight unit 300: backlight driving unit

400: luminance correction unit 111: light sensing unit

PW: Power generating part Drv1: Sequential driving part

Drv2: simultaneous driving unit 401: input control unit

402: luminance adjustment unit 403: memory unit

r: red light source g: green light source

b: blue light source

Claims (25)

A backlight unit having a plurality of light sources for providing light of different colors to the display panel; Controlling the plurality of light sources to sequentially turn on during the sensing / correcting period, controlling the light sources of the remaining colors to be turned off while the light sources of one color are on, and controlling the light sources to be turned on simultaneously during the display period A driving unit; A light sensing unit sequentially sensing the light from the light sources by the color during the sensing / correcting period and generating a luminance signal representing the luminance of each color of the light sources for each color; And And generates the brightness signals for the respective light sources according to the respective colors from the light sensing unit during the sensing / correcting period, and supplies the generated brightness signals to the backlight driver so that the backlight is in contact with the brightness signals And a brightness correction unit for controlling the brightness of the light sources according to the brightness information. The method according to claim 1, The backlight driver includes: A sequential driving unit for controlling the plurality of light sources to sequentially turn on for each color during the sensing / correcting period, and controlling the light sources of the remaining colors to be turned off while the light sources for one color are turned on; And And a simultaneous driver for controlling all of the light sources to be simultaneously turned on during the display period. 3. The method of claim 2, Wherein the sequential driver sequentially outputs a plurality of lighting control signals and sequentially supplies the lighting control signals to the light sources sequentially by color, thereby sequentially driving the light sources according to colors; And, Wherein the simultaneous driving control unit outputs a plurality of driving signals and simultaneously supplies the driving signals to the light sources to simultaneously drive the light sources. The method of claim 3, Wherein the brightness correction unit is supplied with a sensing signal for each color from the light sensing unit according to lighting control signals from the sequential driving unit. 5. The method of claim 4, Wherein the luminance correction unit comprises: An input control unit for sequentially outputting a sensing signal for each color from the light sensing unit according to each lighting control signal from the sequential driving unit; A luminance controller for outputting luminance signals by correcting a sensing signal for each color from the input controller using a preset reference luminance signal; And And a memory unit for storing brightness signals for each color from the brightness controller. 6. The method of claim 5, The input control unit, A first switching device for outputting a first sensing signal from the light sensing unit according to a first lighting control signal; A second switching element for outputting a second sensing signal from the light sensing unit according to a second lighting control signal; And And a third switching element for outputting a third sensing signal from the light sensing unit according to a third lighting control signal. The method according to claim 6, Wherein the brightness adjusting unit comprises: A red luminance controller for outputting a first luminance signal by correcting a first sensing signal from the first switching element using a first reference luminance signal; A green luminance controller for outputting a second luminance signal by correcting a second sensing signal from the second switching element using a second reference luminance signal; And And a blue brightness controller for outputting a third brightness signal by correcting the third sensing signal from the third switching element using a third reference brightness signal. 8. The method of claim 7, Wherein the red luminance controller comprises: A red reference signal generator outputting the first reference luminance signal; An amplifier for amplifying a first sensing signal from the first switching element; An analog-digital converter for converting the amplified first sensing signal from the amplifier into a digital signal; A comparator for comparing a magnitude between a first sensing signal from the analog-to-digital converter and a first reference luminance signal from the red reference signal generator and calculating a correction value indicating a difference therebetween; And And an adder for adding the correction value from the comparator and the first reference luminance signal from the red reference signal generator to generate a first luminance signal. 9. The method of claim 8, The green luminance controller may include: A green reference signal generator outputting the second reference luminance signal; An amplifier for amplifying a second sensing signal from the second switching element; An analog-digital converter for converting the amplified second sensing signal from the amplifying unit into a digital signal; A comparator for comparing a magnitude between a second sensing signal from the analog-to-digital converter and a second reference luminance signal from the green reference signal generator and calculating a correction value indicating a difference therebetween; And And an adder for adding a correction value from the comparator and a second reference luminance signal from the green reference signal generator to generate a second luminance signal. 10. The method of claim 9, The blue luminance controller may include: A blue reference signal generator for outputting the blue light reference luminance signal; An amplifier for amplifying a third sensing signal from the third switching element; An analog-digital converter for converting the amplified third sensing signal from the amplifying unit into a digital signal; A comparator for comparing a magnitude between a third sensing signal from the analog-to-digital converter and a third reference luminance signal from the blue reference signal generator and calculating a correction value indicating a difference therebetween; And And an adder for adding a correction value from the comparator and a third reference luminance signal from the blue reference signal generator to generate a third luminance signal. 11. The method of claim 10, The memory unit, A first memory for storing a first luminance signal from an adder provided in the red luminance controller; A second memory for storing a second luminance signal from an adder provided in the green luminance controller; And And a third memory for storing a third luminance signal from an adder provided in the blue luminance controller. 12. The method of claim 11, During the sensing / correction period, And a control circuit for generating a first lighting control signal based on a first luminance signal stored in the first memory, and a red light source for emitting red light of the light sources using the first lighting control signal, Th drive; And a controller for generating a second lighting control signal based on a second luminance signal stored in the second memory and for generating green light sources for emitting green light among the light sources using the second lighting control signal, Th drive; And, The third light-emitting control signal is generated based on the third luminance signal stored in the third memory, and the blue light sources and the third switching element, which emit the blue light among the light sources, The liquid crystal display device comprising: 13. The method of claim 12, During the display period, the co- Generating a first driving signal based on a first luminance signal stored in the first memory and driving red light sources using the first driving signal; Generating a second driving signal based on a second luminance signal stored in the second memory and driving the green light sources using the second driving signal; And, And generates a third driving signal based on the third luminance signal stored in the third memory, and drives the blue light sources using the third driving signal. The method according to claim 1, Each display period corresponds to a length of a plurality of frame intervals; Each sensing / correcting period corresponds to a length of one blank section; And, Wherein the display period and the sensing / correcting period are alternately generated in time. The method according to claim 1, Each display period corresponds to a length of a plurality of frame intervals; Each sensing / correcting period corresponds to a length of one frame period; And, Wherein the display period and the sensing / correction period are alternately generated in terms of time. The method according to claim 1, In one sense / correction period, First driving red light sources for emitting red light among the light sources; Driving the green light sources emitting the green light for the second time; And, And the blue light sources for emitting the red light of the light sources are driven for the third time. The method according to claim 1, The backlight driver includes: Driving red light sources for emitting red light among the light sources during a first sensing / correcting period; Driving green light sources emitting green light of the light sources during a second sensing / correcting period; And the blue light sources that emit blue light among the light sources are driven during the third sensing / correcting period. The method according to claim 1, And the display unit of the display panel displays a black image during the sensing / correcting period. The method according to claim 1, And the display unit of the display panel sequentially displays a black image in units of horizontal lines during the sensing / correcting period. The method according to claim 1, Wherein the display section of the display panel includes an effective display region for displaying an actual image and a liquid crystal margin region formed around the effective display region; And, Wherein the light sensing unit is formed in the liquid crystal margin region. The method according to claim 1, Wherein the display panel includes first and second substrates facing each other, and a liquid crystal layer disposed between the first substrate and the second substrate; And, And the brightness sensing unit is formed on the first substrate so as to be covered by the black matrix of the second substrate. An A step of preparing a plurality of light sources for emitting light of different colors to a display panel; Controlling the plurality of light sources to be sequentially turned on for each color during the sensing / correcting period, and controlling the light sources of the remaining colors to be turned off while the light sources of one color are turned on; A step C for sequentially sensing the light from the plurality of light sources driven according to the step B during the sensing / correcting period by color and generating a luminance signal representing the luminance of the light sources for each color; And controlling the luminance of the light sources according to the color based on the luminance signal for each color from the step C during the display period and controlling the light sources to be turned on at the same time. Way. 23. The method of claim 22, And the step B is performed during a blank period. 23. The method of claim 22, In the step B, A step J for turning on only the red light sources emitting red light for the first blank period among the three blank periods adjacent to each other; During the second blank period, only the green light sources emitting green light are turned on; And, And turning on only the blue light sources emitting blue light during the third blank period. 23. The method of claim 22, And a black image is displayed on the front surface of the display unit of the display panel during the step B).

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