KR101002320B1 - Liquid crystal display apparatus and driving method thereof - Google Patents

Abstract

The present invention relates to a liquid crystal display device and a driving method thereof capable of improving display quality.

According to an exemplary embodiment of the present invention, a liquid crystal display device which divides one frame into a plurality of subframes and sequentially drives a light source to display an image includes: a liquid crystal panel in which data lines and gate lines are formed and an image is displayed; A plurality of light sources for irradiating light to the liquid crystal panel, a light source driving circuit for driving the plurality of light sources, a data driving circuit for supplying a data signal to the data lines, and a gate signal to the gate line A gate driver circuit, a power generator for supplying a driving voltage to the liquid crystal panel, the data driver circuit, the gate driver circuit and the light source driver circuit, and a timing controller for controlling the data driver circuit, the gate driver circuit and the light source driver circuit. And the timing controller stores the input image signal data in one frame unit. And a frame memory for; And a video signal discrimination and adjusting unit for discriminating and adjusting video signal data stored in the frame memory.

With this configuration, the liquid crystal display according to the exemplary embodiment of the present invention adjusts the brightness of the image displayed on the liquid crystal panel to adjust the light transmittance of the liquid crystal panel and the brightness of the light source of the backlight unit to display the image displayed on the liquid crystal panel without deterioration of color purity. By increasing or decreasing the brightness of the LED, you can improve the display quality in bright and dark images.

Description

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

1 is a perspective view illustrating a general liquid crystal display module.

FIG. 2 is a cross-sectional view of the liquid crystal display module illustrated in FIG. 1 taken along line II ′. FIG.

FIG. 3 is a diagram illustrating a part of a backlight unit constituting the liquid crystal display module illustrated in FIG. 1.

4 is a cross-sectional view of a liquid crystal display module employing three color light sources of red, green, and blue.

FIG. 5A illustrates that only the red light source is turned on in the liquid crystal display module illustrated in FIG. 4.

5B is a view illustrating an image displayed on a liquid crystal panel when a red light source is turned on.

FIG. 6A illustrates that only the green light source is turned on in the liquid crystal display module illustrated in FIG. 4.

6B illustrates an image displayed on the liquid crystal panel when the green light source is turned on.

FIG. 7A illustrates that only the blue light source is turned on in the liquid crystal display module illustrated in FIG. 4.

7B is a view showing an image displayed on the liquid crystal panel when the blue light source is turned on.

FIG. 8A is a view showing that the tricolor light sources of red, green, and blue are driven by the FSC method in the liquid crystal display module shown in FIG. 4.

FIG. 8B is a view showing an image displayed on the liquid crystal panel when the red, green, and blue tricolor light sources are driven in the FSC method in one frame period.

9 is a view showing lighting of tricolor light in one frame period in a general liquid crystal display device.

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

FIG. 11 is a cross-sectional view of the liquid crystal display module illustrated in FIG. 10 taken along the line II-II ′.

FIG. 12 is a diagram illustrating a part of a backlight unit constituting the liquid crystal display module illustrated in FIG. 11.

FIG. 13 is a perspective view illustrating a light emitting diode array having three colors of red, green, and blue colors.

FIG. 14 is a graph for analyzing and displaying brightness of a display image when the image displayed on the liquid crystal panel is a bright image. FIG.

FIG. 15 is a view showing sequential driving of three color light sources of red, green, and blue in a general liquid crystal display module when the image displayed on the liquid crystal panel is a bright image.                 

FIG. 16 is a diagram showing luminance of tricolor light displayed by sequential driving of the tricolor light source shown in FIG.

FIG. 17 is a diagram illustrating sequential driving of red, green, and blue tricolor light sources of the liquid crystal display according to an exemplary embodiment of the present invention when the image displayed on the liquid crystal panel is a bright image.

FIG. 18 is a diagram illustrating luminance of tricolor light displayed by sequential driving of the tricolor light source shown in FIG. 17.

19 is a graph illustrating an analysis of brightness of a display image when the image displayed on the liquid crystal panel is a dark image.

FIG. 20 is a view illustrating sequential driving of three color light sources of red, green, and blue in a general liquid crystal display module when the image displayed on the liquid crystal panel is a dark image.

FIG. 21 is a view showing luminance of tricolor light displayed by sequential driving of the tricolor light source shown in FIG.

FIG. 22 is a diagram illustrating sequential driving of red, green, and blue tricolor light sources of the liquid crystal display according to an exemplary embodiment of the present invention when the image displayed on the liquid crystal panel is a dark image.

FIG. 23 is a diagram showing luminance of tricolor light displayed by sequential driving of the tricolor light source shown in FIG.

FIG. 24 is a view showing lighting of tricolor light during one frame period in the liquid crystal display according to the exemplary embodiment of the present invention.                 

FIG. 25 illustrates a driving apparatus for driving the liquid crystal display module shown in FIG. 10.

FIG. 26 is a detailed diagram of the timing controller illustrated in FIG. 25.

FIG. 27 is a diagram illustrating the liquid crystal panel shown in FIG. 25.

28A to 28C are diagrams showing the brightness distribution of an image displayed on the liquid crystal panel.

29 is a view showing color gamut of a general liquid crystal display device.

30 is a diagram illustrating color gamut of a liquid crystal display according to an exemplary embodiment of the present invention.

FIG. 31 is a view showing a liquid crystal display module employing an edge type backlight unit. FIG.

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

1,30,100: liquid crystal display module 2,102: top case

3,103: lower substrate 5,105: upper substrate

6,36,106: liquid crystal panel 8,38,108: optical sheet

10,40,110: diffuser plate 12,112: reflective sheet

14,114 support main 16,116 bottom cover

18,48,118 lamp housing 20 lamp

22: lamp holder 28: support side                 

50a: red lamp 50b: green lamp

50c: blue lamp 60160: backlight unit

130: light emitting diode array 132: printed circuit board

134: light emitting diode 134a: red light emitting diode

134b: green light emitting diode 134c: blue light emitting diode

170: timing controller 172: data driving circuit

174: gate driving circuit 176: light source driving circuit

178: power generation unit 180: frame memory

182: Image signal discrimination and adjusting unit 124: Light guide plate

The present invention relates to a liquid crystal display device and a driving method thereof, and more particularly, to a liquid crystal display device and a driving method thereof capable of improving display quality.

In general, liquid crystal display (Liquid Crystal Display) due to the characteristics of light weight, thin, low power consumption, etc., the application range is gradually increasing. In accordance with this trend, droplet display devices are used in office automation equipment, audio / video equipment, and the like. On the other hand, the liquid crystal display device displays the desired image on the screen by adjusting the transmission amount of the light beam according to image signals applied to the plurality of control switches arranged in a matrix form.

A general liquid crystal display device is composed of a liquid crystal display module and a driving circuit portion for driving the liquid crystal display module.

The liquid crystal display module includes a liquid crystal panel in which liquid crystal cells are arranged in a matrix form between two glass substrates, and a back light unit for irradiating light to the liquid crystal panel. In addition, a plurality of optical sheets are arranged in the liquid crystal display module to vertically condense the light traveling from the backlight unit toward the liquid crystal panel. The liquid crystal panel, the backlight unit and the optical sheet must be fastened in an integrated form to prevent light loss and must be protected from damage by external impact. To this end, a case for a liquid crystal display device formed to surround the backlight unit and the optical sheets including the edge of the liquid crystal panel is provided. Since the liquid crystal display module is not a self-luminous display device, a light source such as a backlight is required. There are two types of backlight of the liquid crystal display module, a direct type type and an edge type type.

In the edge type system, a light source is installed outside the light guide plate, and the light emitted from the light source is incident on the entire surface of the liquid crystal panel using the transparent light guide plate. The direct type method is a method of directly dimming the front surface of the liquid crystal panel by placing a light source on the rear surface of the liquid crystal panel. Thus, a plurality of light sources may be disposed to increase luminance and widen the light emitting surface as compared to the edge type method.

FIG. 1 is a perspective view illustrating a general liquid crystal display module, and FIG. 2 is a cross-sectional view of the liquid crystal display module shown in FIG. 1 taken along line II ′.

1 and 2, a general liquid crystal display module 1 includes a support main 14, a backlight unit and a liquid crystal panel 6 stacked inside the support main 14, and a liquid crystal panel 6. A top case 2 is provided to surround the edge and the side surface of the support main 14.

The liquid crystal panel 6 includes a spacer (not shown) for injecting liquid crystal between the upper substrate 5 and the lower substrate 3 and for maintaining a constant gap between the upper substrate 5 and the lower substrate 3. . On the upper substrate 5 of the liquid crystal panel 6, a color filter, a common electrode, a black matrix, and the like, which are not shown, are formed. In addition, signal wirings such as data lines and gate lines (not shown) are formed on the lower substrate 3 of the liquid crystal panel 6, and thin film transistors ("TFTs") are formed at intersections of the data lines and the gate lines. Is formed. The TFT switches the data signal to be transmitted from the data line toward the liquid crystal cell in response to the scan signal (gate pulse) from the gate line. The pixel electrode is formed in the pixel region between the data line and the gate line. In addition, a pad area for connecting data lines and gate lines, respectively, is formed at one side of the lower substrate 3, and a tape carrier (not shown) in which a driver integrated circuit for applying a driving signal to a TFT is mounted on the pad area. The package (Tape Carrier Package) is attached. This tape carrier package supplies the data signal from the driver integrated circuit to the data lines. The scan signal is also supplied to the gate lines.

The upper polarizing sheet is attached to the upper substrate 5 of the liquid crystal panel 6, and the lower polarizing sheet is attached to the rear surface of the lower substrate 3.

The support main 14 is a mold, and the side wall surface thereof is formed into a stepped stepped surface, and the stepped surface is formed with a seating portion on which a plurality of optical sheets 8 are seated. Inside the support main 14, a backlight unit for irradiating light to the liquid crystal panel 6 and a liquid crystal panel 6 are stacked.

The backlight unit includes a plurality of lamps 20 for irradiating light to the liquid crystal panel 6, a plurality of lamp holders 22 to which the plurality of lamps 20 are mounted and fixed, and a plurality of lamps 20. A diffuser plate 10 for diffusing light incident from the light source to the liquid crystal panel 6, a lamp housing 18 disposed on the rear surface of the plurality of lamps 20, and a length in the longitudinal direction of the lamp housing 18. It is composed of a support side 28 respectively provided on the side, and a plurality of optical sheets 8 stacked on the diffusion plate 10.

The plurality of lamps 20 is mainly used a cold cathode fluorescent lamp, each of the plurality of lamps 20 is composed of a glass tube, inert gas inside the glass tube, and a cathode and an anode installed at both ends of the glass tube do. Inert gas is filled in the glass tube, and phosphor is coated on the inner wall of the glass tube. As shown in FIG. 3, the plurality of lamps 20 are divided into groups of N (N is a positive integer) and mounted and fixed to the lamp holder 22. Light generated by the plurality of lamps 20 is incident on the diffuser plate 10.

The diffuser plate 10 directs the light incident from the plurality of lamps 20 toward the front direction of the liquid crystal panel 6 and diffuses the light so that the diffuser plate has a uniform distribution in a wide range. We investigate in (6). The diffusion plate 10 is a coating of the light diffusion member on both sides of the film made of a transparent resin.

The lamp housing 18 is composed of a reflective sheet 12 and a bottom cover 16 disposed on the rear surface of the reflective sheet 12, as shown in FIG.

The reflective sheet 12 is disposed on the back of the plurality of lamps 20. The reflective sheet 12 is formed of a material that reflects light, and has the same shape as the bottom cover 16, and is bent to correspond to the bottom surface overlapping the bottom surface of the bottom cover 16 and the inclined surface of the bottom cover 16. It has an inclined surface. The reflective sheet 12 is attached to the bottom surface and the inclined surface of the bottom cover 16 by an adhesive double-sided tape (not shown). The reflective sheet 12 reflects the light traveling toward the rear and side surfaces of the plurality of lamps 20 toward the liquid crystal panel 6 to improve the efficiency of the light irradiated onto the liquid crystal panel 6.

The bottom cover 16 has a bottom surface and an inclined surface extending from the bottom surface. That is, the bottom surface and the inclined surface of the bottom cover 16 are stepped with each other. The reflective sheet 12 is laminated on the bottom cover 16.

The support side 28 is installed in each of the longitudinal side of the lamp housing 18. The support side 28 is formed with an inclined surface having a predetermined slope and an insertion portion into which both side surfaces of the plurality of lamps 20 are inserted. Both sides of the plurality of lamps 20 are inserted into this insertion portion. By this structure, the support side 28 supports the plurality of lamps 20. For this purpose, the support side 28 is fixed to the lamp housing 18 by screws, not shown. The support side 28 serves to support the plurality of lamps 20 and transmits light propagating from the plurality of lamps 20 to both sides of the lamp housing 18. The reflection is made to proceed toward the side to improve the efficiency of light irradiated to the liquid crystal panel 6.

Light emitted through the diffusion plate 10 is incident on the liquid crystal panel 6 via the plurality of optical sheets 8.

The light emitted from the diffuser plate 10 has a large viewing angle as diffuse light. When the light incident on the liquid crystal panel 6 is vertical, the light efficiency is increased. For this purpose, the optical sheets 8 are arranged on the diffuser plate 10.

The plurality of optical sheets 8 generates light emitted from the diffuser plate 10 vertically to improve light efficiency. Accordingly, the light emitted from the diffuser plate 10 is incident on the liquid crystal panel 6 via the plurality of optical sheets 8.

The top case 2 is manufactured in the form of a square strip having a flat portion and a side portion bent at a right angle. The top case 2 surrounds the edge of the liquid crystal panel 6 and the support main 14.

The general liquid crystal display module 1 having such a structure has low light transmittance due to light absorption of the color filter, and thus, the luminance of the image displayed on the liquid crystal panel 6 is low, and the color purity is low due to the characteristics of the color filter. A plurality of lamps 20 are driven in a hold type driving method, that is, a method in which a plurality of lamps 20 are continuously turned on, so that power consumption is large. In addition, the liquid crystal display module 1 has a slow response characteristic of the liquid crystal and a holding characteristic of the liquid crystal, so that the blurring motion blur phenomenon or the tailing phenomenon that the contour appears to be drawn when the moving image is realized, and the previous screen affect the next screen. This results in a blur that blurs the screen, resulting in deterioration of the image quality of the liquid crystal display module.

In order to remedy the above disadvantages, as shown in Fig. 4, the light source employs red, green and blue lamps 50a to 50c and these red, green and blue lamps 50a to 50c are sequentially A liquid crystal display module 30 for driving has been proposed.

The liquid crystal display module 30 shown in FIG. 4 has the same light source as the three color light sources of the red lamp 50a, the green lamp 50b, and the blue lamp 50c, and the color filter is deleted. Since it has the same components as the liquid crystal display module 1, detailed description thereof will be omitted.

The liquid crystal display module 30 employing the three color light sources of the red lamp 50a, the green lamp 50b, and the blue lamp 50c has the color filter removed, and the red lamp 50a, the green lamp 50b, and the blue lamp ( It is driven by the 'Field Sequential Control' method (hereinafter referred to as "FSC") which sequentially flashes the tricolor light source of 50c).

As shown in FIG. 9, the liquid crystal display module 30 driven by the FSC method charges the red data to the liquid crystal cell during the scan time of the TFT, and then turns off the red lamp 50c after the response time of the liquid crystal. Lights up to indicate red color for a period shorter than the ⅓ frame period. After red is displayed, green and blue are displayed by writing green data and lighting of the green lamp 50b, followed by writing of blue data and lighting of the blue lamp 50c.

In more detail, the liquid crystal display module 30 for displaying an image by driving the tricolor light sources of the red lamp 50a, the green lamp 50b, and the blue lamp 50c of the backlight unit 60 in the FSC method is limited. The frame period is driven by dividing the response time of the liquid crystal and the lighting time of the lamps 50a, 50b, and 50c. As shown in FIG. 5A for a time shorter than the frame period, when the red lamp 50a is turned on, an image as shown in FIG. 5B is displayed on the liquid crystal panel 36 by the emitted red light. Then, the red lamp 50a is turned off and the green lamp 50b is turned on, as shown in Fig. 6A, for a time shorter than the ⅓ frame period. When the green lamp 50b is turned on, the image shown in FIG. 6B is displayed on the liquid crystal panel 36 by the emitted green light. Then, the green lamp 50b goes out and the blue lamp 50c is turned on, as shown in Fig. 7A, for a time shorter than the ⅓ frame period. When the blue lamp 50c is turned on, an image as shown in FIG. 7B is displayed on the liquid crystal panel 36 by the emitted blue light. When the backlight unit 60 is driven through this driving method, as shown in FIG. 8A, all three color light sources of the red lamp 50a, the green lamp 50b, and the blue lamp 50c are turned on for one frame period. As shown in Fig. 8B, the panel 36 displays the original image to be displayed by displaying all the colors.

The liquid crystal display module for driving the three color light sources of the red lamp 50a, the green lamp 50b, and the blue lamp 50c by the FSC method eliminates the color filter and the red lamp 50a, the green lamp 50b, and the blue lamp. The luminance and color purity are high by employing the tricolor light source of 50c, but the lighting time of the red lamp 50a, the green lamp 50b, and the blue lamp 50c is reduced by the scanning time and the response time of the liquid crystal, so that the effect of increasing the brightness is almost reduced. There is a problem in that the display quality is poor when expressing a bright screen such as an instant explosion or a dark screen such as a night by controlling the brightness of an image displayed on the liquid crystal panel 36 only by the light transmittance of the liquid crystal cell.

Accordingly, an object of the present invention is to provide a liquid crystal display device and a driving method thereof capable of improving display quality.

In order to achieve the above object, a liquid crystal display device according to an embodiment of the present invention is divided into a plurality of sub-frames and a liquid crystal display device for displaying an image by sequentially driving the light source, the data line and the gate line is formed A liquid crystal panel displaying an image, a plurality of light sources for irradiating light to the liquid crystal panel, a light source driving circuit for driving the plurality of light sources, a data driving circuit for supplying a data signal to the data lines, and A gate driving circuit for supplying a gate signal to a gate lie, a power generation unit supplying a driving voltage to the liquid crystal panel, the data driving circuit, the gate driving circuit and the light source driving circuit, the data driving circuit, the gate driving circuit and the light source; A timing controller for controlling a driving circuit, wherein the timing controller inputs an image signal; A frame memory for storing data in one frame unit; And a video signal discrimination and adjusting unit for discriminating and adjusting video signal data stored in the frame memory.                     

Each of the plurality of light sources of the liquid crystal display according to the embodiment of the present invention is characterized in that it emits one of the color light of red, green and blue light.

The light source of the liquid crystal display according to an exemplary embodiment of the present invention may be a plurality of red light emitting diodes emitting red light, a green light emitting diode emitting green light, and a blue light emitting diode emitting blue light.

According to an exemplary embodiment of the present invention, a liquid crystal display device includes a red frame which emits the red light emitting diode as a main light source, a green frame which emits the green light emitting diode as a main light source, and the blue light emitting diode as a main light source. It is characterized by being driven by dividing into a blue frame to emit light.

The red light emitting diodes, the green light emitting diodes, and the blue light emitting diodes of the liquid crystal display according to the embodiment of the present invention are characterized in that the flashing sequentially.

The image signal discrimination and adjusting unit of the liquid crystal display according to an embodiment of the present invention determines the brightness level of the image signal data input in units of one frame and adjusts the image signal data according to the determined result to adjust the image signal. And supplying data to the data driver.

In the liquid crystal display according to the embodiment of the present invention, when the determined image signal data is a video signal displaying a bright image, the main light source is turned on for each of the red frame, green frame, and blue frame periods. The sub-light sources other than the main light source are also turned on.

The sub light sources of the liquid crystal display according to the exemplary embodiment of the present invention are turned on at a predetermined brightness to increase the brightness of the image displayed on the liquid crystal panel.

The main light source of the liquid crystal display according to an exemplary embodiment of the present invention is characterized in that the brightness is increased in proportion to the brightness of the sub light source is turned on.

According to an exemplary embodiment of the present invention, when the determined image signal data is a video signal displaying a dark image, only the main light source is turned on during each of the red frame, green frame, and blue frame periods. do.

The main light source of the liquid crystal display according to an exemplary embodiment of the present invention may be controlled to be turned on at a lower brightness than the brightness of the input original image signal data.

The brightness of the main light source and the sub light source of the liquid crystal display according to an exemplary embodiment of the present invention is controlled by a voltage or a current value supplied from the light source driving circuit.

A driving method of a liquid crystal display device according to an exemplary embodiment of the present invention is a driving method of a liquid crystal display device which divides one frame into a plurality of subframes and sequentially drives a plurality of light sources to display an image. And providing a timing controller for controlling the light source driving circuit, storing image signal data input to the timing controller in a frame memory in units of frames, and storing image signal data in units of frames stored in the frame memory. Determining brightness through an image signal discrimination and control unit; adjusting the video signal data through the video signal discrimination and adjustment unit according to a result of the image signal discrimination and control unit; and Driving the light source to correspond to the image signal data adjusted by the The furnace is characterized in that it comprises a step of supplying a light source control signal.

The light source of the method of driving an LCD according to an embodiment of the present invention is characterized in that the plurality of red light emitting diodes, green light emitting diodes and blue light emitting diodes emitting red, green and blue light.

According to an exemplary embodiment of the present invention, a driving method of a liquid crystal display device includes a red frame for emitting a red light emitting diode as a main light source, a green frame for emitting a green light emitting diode as a main light source, and a blue light emitting diode as a main light source. It is characterized by being driven by dividing into a blue frame to emit light.

A method of driving a liquid crystal display according to an exemplary embodiment of the present invention is characterized in that the red light emitting diode, the green light emitting diode, and the blue light emitting diode are sequentially flashed.

The driving method of the liquid crystal display according to an exemplary embodiment of the present invention may further include supplying the adjusted image signal data to the data driver.

According to an exemplary embodiment of the present invention, when the determined image signal data is a video signal displaying a bright image, the main light source is turned on during each of the red, green, and blue frame periods. In addition, it is characterized in that the sub-light sources other than the main light source.

The driving method of the liquid crystal display according to the exemplary embodiment of the present invention is characterized in that the sub light sources are turned on at a predetermined brightness to increase the brightness of the image displayed on the liquid crystal panel.

The driving method of the liquid crystal display according to an exemplary embodiment of the present invention is characterized in that the main light source is turned on by increasing its brightness in proportion to the brightness of the sub light sources.

According to an exemplary embodiment of the present invention, when the determined image signal data is a video signal displaying a dark image, only the main light source is turned on during each of the red, green, and blue frame periods. It is characterized by.

The driving method of the liquid crystal display device according to an exemplary embodiment of the present invention is characterized in that the main light source is adjusted to a brightness lower than the brightness of the input original image signal data and is turned on.

The driving method of the liquid crystal display according to the exemplary embodiment of the present invention is characterized in that the brightness of the main light source and the sub light source is controlled by a voltage or a current value supplied from the light source driving circuit.

Other objects and features of the present invention in addition to the above objects will be apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, a liquid crystal display and a driving method thereof according to embodiments of the present invention will be described in detail with reference to FIGS. 10 to 31.

FIG. 10 is a perspective view illustrating a liquid crystal display module of a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 11 is a cross-sectional view of the liquid crystal display module shown in FIG. 10 taken along a line II-II '.

10 and 11, the liquid crystal display module 100 of the liquid crystal display according to the exemplary embodiment of the present invention includes a support main 114, a backlight unit and a liquid crystal panel stacked inside the support main 114. 106 and a top case 102 for wrapping the edge of the liquid crystal panel 106 and the side surface of the support main 114.

The liquid crystal panel 106 includes a spacer (not shown) for injecting liquid crystal between the upper substrate 105 and the lower substrate 103 and for maintaining a constant gap between the upper substrate 105 and the lower substrate 103. . The common electrode, not shown, is formed on the upper substrate 105 of the liquid crystal panel 106. In addition, signal lines such as data lines and gate lines (not shown) are formed on the lower substrate 103 of the liquid crystal panel 106, and thin film transistors ("TFTs") at the intersections of the data lines and the gate lines. Is formed. The TFT switches the data signal to be transmitted from the data line toward the liquid crystal cell in response to the scan signal (gate pulse) from the gate line. The pixel electrode is formed in the pixel region between the data line and the gate line. In addition, a pad area for connecting data lines and gate lines, respectively, is formed at one side of the lower substrate 103, and the tape carrier (not shown) in which a driver integrated circuit for applying a driving signal to the TFT is mounted on the pad area. The package (Tape Carrier Package) is attached. This tape carrier package supplies the data signal from the driver integrated circuit to the data lines. The scan signal is also supplied to the gate lines. The upper polarizing sheet is attached to the upper substrate 105 of the liquid crystal panel 106, and the lower polarizing sheet is attached to the rear surface of the lower substrate 103.

The liquid crystal panel 106 of the liquid crystal display device according to the embodiment of the present invention improves the productivity of the liquid crystal display device by removing the color filter formed on the liquid crystal panel 6 of the general liquid crystal display device, and the light of the color filter. The luminance may be improved by eliminating a phenomenon in which light transmittance is lowered due to absorption.

The support main 114 is a mold, and the side wall surface therein is formed into a stepped stepped surface, and the stepped surface is formed with a seating portion on which the plurality of optical sheets 108 are seated. Inside the support main 114, a backlight unit for irradiating light to the liquid crystal panel 106 and a liquid crystal panel 106 are stacked.

The backlight unit includes a plurality of LED arrays 130 including a plurality of light emitting diodes (hereinafter referred to as "LEDs") 134 for irradiating light to the liquid crystal panel 106, and a plurality of LEDs 134. Diffusion plate 110 for diffusing the light incident from the light into the liquid crystal panel 106, the reflective sheet 112 disposed on the rear surface of the plurality of LED arrays 130, and the diffusion plate 110. It consists of a plurality of optical sheets 108 stacked.

12 and 13, the plurality of LED arrays 130 includes a printed circuit board on which a plurality of LEDs 134 to generate light and a circuit for controlling light emission of the plurality of LEDs 134 are mounted. Printed Circuit Board: hereinafter referred to as " PCB " LED 132 emits a unique color light (e.g. red, green and blue) as a point light source. The PCB 132 supports the LED 134 and controls the light emission of the LED 134 by a circuit configured therein. Light generated by the LED 134 is incident on the diffuser plate 110. The light propagated to the lower surface of the LED array 130 is reflected by the reflecting sheet 112 and proceeds toward the diffuser plate 110.

The diffusion plate 110 directs the light incident from the plurality of LEDs 134 emitting red, green, and blue unique color light toward the front direction of the liquid crystal panel 106, and diffuses the light so that the light is uniform in a wide range. The diffused light is irradiated onto the liquid crystal panel 106 to have a distribution. The diffusion plate 110 is used to coat the light diffusion member on both sides of the film made of a transparent resin.

The reflective sheet 112 is disposed on the back of the plurality of LED arrays 130. The reflective sheet 112 is formed of a material that reflects light to reflect the light traveling toward the rear surface of the plurality of LED arrays 130 toward the liquid crystal panel 106 to improve the efficiency of the light irradiated onto the liquid crystal panel 106.

Light emitted through the diffusion plate 110 is incident on the liquid crystal panel 106 via the plurality of optical sheets 108. The light emitted from the diffuser plate 110 is formed with diffused light so that a viewing angle is large. When the light incident on the liquid crystal panel 106 is vertical, the light efficiency is increased. To this end, a plurality of optical sheets 108 are disposed on the diffuser plate 110.

The plurality of optical sheets 108 concentrate light emitted from the diffuser plate 110 vertically to improve light efficiency. Accordingly, the light emitted from the diffuser plate 110 is incident on the liquid crystal panel 106 via the plurality of optical sheets 108.

The top case 102 is manufactured in the form of a square strip having a flat portion and a side portion bent at a right angle. The top case 102 surrounds the edge of the liquid crystal panel 106 and the support main 114.

FIG. 14 is a graph for analyzing and displaying brightness of a display image when the image displayed on the liquid crystal panel is a bright image. FIG.

Referring to FIG. 14, when the image displayed on the liquid crystal panel 36 is a bright image, the general liquid crystal display module 30 emits light to the liquid crystal panel 36 as shown in FIG. 15. ), The tricolor light sources of the green lamp 50b and the blue lamp 50c are driven in the FSC method so that the red lamp 50a, the green lamp 50b, and the blue lamp 50c are shown in FIG. 16 during one frame period. ), All three color light sources are turned on to express the color and luminance to be expressed. However, as described above, the luminance is adjusted only by the light transmittance of the liquid crystal panel 36, so that the image is brightened instantaneously and the image displaying high luminance is displayed. There is a disadvantage that cannot express all the luminance.

According to an exemplary embodiment of the present invention, when the image displayed on the liquid crystal panel is a bright image as shown in FIG. 28C, the brightness information of each unit pixel of the display image is accumulated according to the brightness level. Histogram) and determines the degree of light and dark of the image to be displayed based on the accumulated brightness information.

According to an exemplary embodiment of the present invention, as shown in FIG. 17 with the determined brightness information, a red LED 134a, a green LED 134b, and a blue LED ( The tricolor light source of 134c) is driven by the FSC method. In more detail, one frame period includes a red frame for lighting the red LED 134a as the main light source, a green frame for lighting the green LED 134b as the main light source, and a blue LED 134c. ) Is divided into three subframes of a blue frame which is turned on by the main light source.

The green LED 134b which turns on the red LED 134a which emits the red light which is the primary color light in the red frame period in which the red LED 134a is turned on as the main light source, and emits green light and blue light which is not the main light source. ) And the blue LED 134c are turned on. At this time, the green LED 134b and the blue LED 134c are turned on at a predetermined brightness to increase the brightness, and the brightness of the red LED 134a emitting the primary color light is in accordance with the brightness of the green LED 134b and the blue LED 134c. Increase proportionately.

The red LED 134a which turns on the green LED 134b that emits green light, which is the primary color light, and emits red light and blue light instead of the main light source in the green frame period in which the green LED 134b is turned on as the main light source. ) And the blue LED 134c are turned on. At this time, the red LED 134a and the blue LED 134c are turned on at a predetermined brightness to increase the brightness, and the brightness of the green LED 134b that emits the primary color light is based on the brightness of the red LED 134a and the blue LED 134c. Increase proportionately.

The red LED 134a which turns on the blue LED 134c which emits blue light, which is the primary color light, and emits red light and green light, which is not the main light source, in the blue frame period in which the blue LED 134c is turned on by the main light source. ) And the green LED 134b are turned on. At this time, the red LED 134a and the green LED 134b are turned on at a predetermined brightness to increase the brightness, and the brightness of the blue LED 134c emitting the primary color light is the brightness of the red LED 134a and the green LED 134b. Increase in proportion to.

Brightness of the red LED 134a, the green LED 134b, and the blue LED 134c is applied to each of the red LED 134a, the green LED 134b, and the blue LED 134c, as shown in FIG. Adjusted by voltage or current value.

In the liquid crystal display according to the exemplary embodiment of the present invention, the tricolor light sources of the red LEDs 134a, the green LEDs 134b, and the blue LEDs 134c are driven by the FSC method, and as shown in FIG. The tricolor light sources of the LED 134a, the green LED 134b, and the blue LED 134c are all lit to express the color and luminance to be expressed.

The liquid crystal display according to the embodiment of the present invention improves color purity by adopting three colors of light of the red LED 134a, the green LED 134b, and the blue LED 134c as the light source of the backlight unit 160, and general liquid crystal. The color filter formed in the liquid crystal panel 106 of the display device may be deleted to prevent the luminance decrease caused by the color filter. In addition, the brightness of the image displayed on the liquid crystal panel 106 is expressed by adjusting the light transmittance of the liquid crystal panel 106 and the brightness of the light source of the backlight unit 160. In the emission period (subframe) of a specific primary color light, the light sources of the other two color lights except for the main color light are turned on at a predetermined brightness, and the brightness of the light source emitting the primary color light is increased in proportion to the brightness of the light sources of the other two color lights. The display quality of the bright image may be improved by increasing the luminance of the image displayed on the liquid crystal panel 106 without degrading the color purity.                     

19 is a graph illustrating an analysis of brightness of a display image when the image displayed on the liquid crystal panel is a dark image.

Referring to FIG. 19, when the image displayed on the liquid crystal panel 36 is a bright image, the general liquid crystal display module 30 may emit a red lamp 50a that irradiates light onto the liquid crystal panel 36. ), The tricolor light sources of the green lamp 50b and the blue lamp 50c are driven by the FSC method so that the red lamp 50a, the green lamp 50b and the blue lamp 50c are shown in Fig. 21 during one frame period. In the three-color light source of (), all the lights are turned on to express the color and luminance to be expressed. There is a disadvantage that cannot express all desired luminance.

According to an exemplary embodiment of the present invention, when the image displayed on the liquid crystal panel is a dark image as shown in FIG. 28B, the brightness information of each unit pixel of the display image is accumulated according to the brightness level. Histogram) and determines the degree of light and dark of the image to be displayed based on the accumulated brightness information.

According to the exemplary embodiment of the present invention, as shown in FIG. 22 with the determined brightness information, a red LED 134a, a green LED 134b, and a blue LED (that irradiates light to the liquid crystal panel 106) The tricolor light source of 134c) is driven by the FSC method. In more detail, one frame period includes a red frame for lighting the red LED 134a as the main light source, a green frame for lighting the green LED 134b as the main light source, and a blue LED 134c. ) Is divided into three subframes of a blue frame which is turned on by the main light source.

A green LED 134b that turns on a red LED 134a that emits red light as the primary color light in a red frame period in which the red LED 134a is turned on as the main light source, and emits green light and blue light that are not the main light source; The blue LED 134c does not light up. At this time, the brightness of the red LED 134a emitting the primary color light is lower than the brightness of the LED in the case of displaying image data of general brightness.

A red LED 134a that lights up the green LED 134b that emits green light, which is the primary color light, in the green frame period in which the green LED 134b is turned on by the main light source, and emits red light and blue light that are not the main light source; The blue LED 134c does not light up. At this time, the brightness of the green LED 134b emitting the primary color light is lower than the brightness of the LED in the case of displaying image data of general brightness.

A red LED 134a which turns on a blue LED 134c which emits blue light as main color light in a blue frame period in which the blue LED 134c is turned on as a main light source, and emits red light and green light which are not the main light source; The green LED 134b does not light up. At this time, the brightness of the blue LED 134c emitting the primary color light is lower than the brightness of the LED when displaying image data of general brightness.

The liquid crystal display according to the exemplary embodiment of the present invention is driven by a general method of driving a liquid crystal display when the image displayed on the liquid crystal panel is a normal brightness image as shown in FIG. 28A.

The brightness of the red LED 134a, the green LED 134b and the blue LED 134c is applied to each of the red LED 134a, the green LED 134b and the blue LED 134c, as shown in FIG. Adjusted by voltage or current value.

In the liquid crystal display according to the exemplary embodiment of the present invention, the tricolor light sources of the red LEDs 134a, the green LEDs 134b, and the blue LEDs 134c are driven by the FSC method, as shown in FIG. 23 during one frame period. The tricolor light sources of the LED 134a, the green LED 134b, and the blue LED 134c are all lit to express the color and luminance to be expressed.

The liquid crystal display according to the embodiment of the present invention improves color purity by adopting three colors of light of the red LED 134a, the green LED 134b, and the blue LED 134c as the light source of the backlight unit 160, and general liquid crystal. The color filter formed in the liquid crystal panel 106 of the display device may be deleted to prevent the luminance decrease caused by the color filter. In addition, the brightness of the image displayed on the liquid crystal panel 106 is expressed by adjusting the light transmittance of the liquid crystal panel 106 and the brightness of the light source of the backlight unit 160. In the emission period (subframe) of a specific primary color light, the brightness of the light source that emits the primary color light is lower than the brightness of the original image data without turning on the light sources of the other two color lights except the light source of the primary color light, thereby reducing the color purity. The display quality in the dark image can be improved by reducing the luminance of the image displayed on the panel 106.

In the above description, the light source is an LED emitting color light of red, green, and blue color. However, not only the LED but also light sources emitting color light such as color fluorescent lamps or organic ELs also display liquid crystal display according to an exemplary embodiment of the present invention. Applicable to the device.

FIG. 25 is a diagram illustrating a driving device for driving the liquid crystal display module shown in FIG. 10.

Referring to FIG. 25, a liquid crystal display according to an exemplary embodiment of the present invention drives the liquid crystal cell Clc formed at the intersections of the data lines D1 to Dm and the gate lines G1 to Gn. A liquid crystal panel 106 having TFTs formed therein, a data driving circuit 172 for supplying data to the data lines D1 to Dm of the liquid crystal panel 106, and gate lines G1 of the liquid crystal panel 106. A gate driving circuit 174 for supplying scan pulses to ˜Gn, a plurality of red LEDs 134a, green LEDs 134b, and blue LEDs 134c for irradiating light to the liquid crystal panel 106; A light source driving circuit 176 for sequentially driving the plurality of red LEDs 134a, green LEDs 134b, and blue LEDs 134c, a data driving circuit 172, a gate driving circuit 174, and a light source driving circuit. To control 176, fill in timing controller 170, liquid crystal panel 106, data driver circuit 172, gate driver circuit 174, and light source driver circuit 176. A power generator 178 for supplying required power is provided.

In the liquid crystal panel 106, liquid crystal is injected between two glass substrates. The TFTs formed at the intersections of the data lines D1 to Dm and the gate lines G1 to Gn of the liquid crystal panel 102 are in response to the scanning pulses from the gate driving circuit 174. ) Is supplied to the liquid crystal cell (Clc). For this purpose, the gate electrode of the TFT is connected to the gate lines G1 to Gn, and the source electrode is connected to the data lines D1 to Dm. The drain electrode of the TFT is connected to the pixel electrode of the liquid crystal cell Clc. In each liquid crystal cell Clc of the liquid crystal panel 106, a storage capacitor Cst is formed to maintain a constant voltage charged in the liquid crystal cell Clc.                     

After the data driving circuit 172 samples the data according to the data control signal DDC from the timing controller 170, the data driving circuit 172 latches the sampled data by one line, and latches the latched data to the data lines D1 to Dm. Supply. In addition, the adjusted digital pixel data R ', G', and B 'from the timing controller 170 convert the gamma voltages GMA1 to 6 input from the power supply generator 178 into analog gamma voltages to convert the data lines. To D1 to Dm.

The gate driving circuit 174 may include a shift register for sequentially generating gate pulses in response to a gate start pulse GSP among the gate control signals GDC from the timing controller 170, and a voltage of the gate pulses to the liquid crystal cell Clc. A level shifter for shifting to a voltage level suitable for driving. The gate driving circuit 174 sequentially supplies the gate high voltage Vgh and the gate low voltage Vgl to the gate lines G1 to Gn in response to the gate control signal GDC.

The plurality of LEDs 134 sequentially flash under the control of the light source driving circuit 176 to emit unique color light. Color light emitted from the plurality of LEDs 134 is irradiated to the liquid crystal panel 106 via a diffusion plate and a plurality of optical sheets which are not shown.

The light source driving circuit 176 sequentially drives the plurality of LEDs 134 in response to the light source control signal FMC from the timing controller 170. The light source driving circuit 176 receives the light source driving voltage Vinv from the power generator 178 to drive the plurality of LEDs 134.

The timing controller 170 rearranges the image signal data supplied from the outside for each of red (R), green (G), and blue (B). The video signal data R, G, and B rearranged by the timing controller 170 are stored in a frame unit in the frame memory 180 shown in FIG. 26. The image signal data R, G, and B stored in the frame memory 180 in frame units are transmitted to the image signal discrimination and adjustment unit 182, and the image signal discrimination and adjustment unit 182 receives the input image signal data R, The brightness levels of the G and B are discriminated, and the determined image signal data R, G and B are displayed on each pixel of the liquid crystal panel 106 in one frame period as shown in FIG. The adjusted image signal data R ', G'B' is supplied to the data driving circuit 172 by adjusting to a brightness level.

17 and 18 illustrate light sources for irradiating light to the liquid crystal panel 106 when the brightness level (Gray Level) of the image displayed on the liquid crystal panel 106 during the one frame period is a bright image as shown in FIG. When the brightness of the image displayed on the liquid crystal panel 106 is increased by driving as shown in FIG. 19 and the brightness level of the image displayed on the liquid crystal panel 106 is dark as shown in FIG. A light source for irradiating light to the panel 106 is driven as described in FIGS. 22 and 23 to decrease the luminance of the image displayed on the liquid crystal panel 106 to increase the display quality of the image displayed on the liquid crystal panel 106. Can be.

In addition, the timing controller 170 generates and supplies a light source control signal FMC to the light source driving circuit 176 to adjust the light source so as to correspond to the adjusted image signal data R 'and G'B'. The data control signal DDC for controlling the data driving circuit 172 and the gate driving circuit 174 by using the horizontal and vertical synchronizing signals H and V and the clock signal CLK inputted to the control circuit. The gate control signal GDC is generated.

The data control signal (DDC) includes a source start pulse (SSP), a source shift clock (SSC), a source output signal (SOE), a dot clock (Dclk), and a polarity inversion signal ( Polarity (POL) and the like are supplied to the data driving circuit 172.

The gate control signal GDC includes a gate start pulse (GSP), a gate shift clock (GSC), a gate output signal (GOE), and the like to the gate driving circuit 106. Supplied.

The light source driving circuit 176 receives the light source control signal FMC from the timing controller 170 and controls the light source according to the brightness of the image displayed on the liquid crystal panel 106.

The power generator 178 includes the common electrode voltage Vcom on the liquid crystal display panel 106, the gamma voltage GMA1 to 6 on the data driver 172, the gate high voltage Vgh on the gate driver 174, and the gate low. The voltage Vgl and the light source driving voltage Vinv are supplied to the light source driver 176.

In the general liquid crystal display device, the color purity of the image displayed on the liquid crystal panel using a color filter was about 60% of that of the NTSC (National Television System Committee), as shown in FIG. 29. A liquid crystal display device according to an embodiment of the present invention for displaying an image on 106 uses color LEDs to eliminate color filters and to emit light of red, green, and blue light sources. As shown, it can be improved by more than 90% on average compared to NTSC.

According to an exemplary embodiment of the present invention, a liquid crystal display device drives a tricolor light source of a red LED 134a, a green LED 134b, and a blue LED 134c in an FSC manner, and thus, the red LED 134a and the green LED (for a frame period). Both the 134b) and the three-color light sources of the blue LED 134c are turned on to express the color and luminance to be expressed. In addition, the brightness of the image displayed on the liquid crystal panel 106 is expressed by adjusting the light transmittance of the liquid crystal panel 106 and the brightness of the light source of the backlight unit 160. In the emission period (subframe) of a specific primary color light, the light sources of the other two color lights except for the main color light are turned on at a predetermined brightness, and the brightness of the light source emitting the primary color light is increased in proportion to the brightness of the light sources of the other two color lights. The display quality of the bright image may be improved by increasing the luminance of the image displayed on the liquid crystal panel 106 without degrading the color purity. The light source in the case where the brightness of the light source emitting the main color light is displayed without displaying the light source of the other color light except the light source of the main color light in the emission period (subframe) of the specific main color light. The brightness of the image may be lowered to lower the brightness of the image, thereby reducing the brightness of the image displayed on the liquid crystal panel 106, thereby improving display quality in the dark image.

In the liquid crystal display according to the present invention, a motion blur phenomenon in which a screen is blurred or a tailing phenomenon in which an outline is attracted and a blur phenomenon in which a screen is blurred by affecting the next screen when a moving image is implemented It can prevent the occurrence and improve the display quality.

In the above description, the light source of the liquid crystal display according to the exemplary embodiment of the present invention is disposed on the rear surface of the liquid crystal panel 106 to directly illuminate the front surface of the liquid crystal panel 106. As shown, the light source may be disposed outside the light guide plate 124 to be applied to an edge type method of dimming light emitted from the light source to the entire surface of the liquid crystal panel 106 using the transparent light guide plate 124.

As described above, the liquid crystal display according to the exemplary embodiment of the present invention employs a plurality of LEDs 134 that eliminate color filters and emit light of red, green, and blue light sources, and the color reproducibility is 90% or more higher than that of NTSC. Can be improved.

The liquid crystal display according to the embodiment of the present invention expresses the color and luminance to be expressed by driving the tricolor light source of the red LED, the green LED, and the blue LED by the FSC method. In addition, the brightness of the image displayed on the liquid crystal panel is adjusted to adjust the light transmittance of the liquid crystal panel and the brightness of the light source of the backlight unit to increase or decrease the brightness of the image displayed on the liquid crystal panel without decreasing the color purity. The display quality can be improved.

In the liquid crystal display according to the present invention, a motion blur phenomenon in which a screen is blurred or a tailing phenomenon in which an outline is attracted and a blur phenomenon in which a screen is blurred by affecting the next screen when a moving image is implemented It can prevent the occurrence and improve the display quality.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (24)

A liquid crystal display device which displays an image by dividing one frame into a plurality of subframes and sequentially driving a light source. A liquid crystal panel in which data lines and gate lines are formed and an image is displayed; A plurality of light sources for irradiating light to the liquid crystal panel; A light source driving circuit for driving the plurality of light sources; A data driving circuit for supplying a data signal to the data line; A gate driving circuit for supplying a gate signal to the gate lie; A power generator for supplying a driving voltage to the liquid crystal panel, the data driving circuit, the gate driving circuit, and the light source driving circuit; A timing controller controlling the data driving circuit, the gate driving circuit, and the light source driving circuit; The timing controller is A frame memory for storing the input image signal data in one frame unit; A video signal discrimination and adjusting unit for discriminating and adjusting video signal data stored in the frame memory; The image signal discrimination and adjusting unit And determining the brightness level of the video signal data input in one frame unit and adjusting the video signal data according to the determined result to supply the adjusted video signal data to the data driver. The method of claim 1, And each of the plurality of light sources emits one of color lights of red, green, and blue light. The method of claim 2, The light source includes a plurality of red light emitting diodes emitting red light, a green light emitting diode emitting green light, and a blue light emitting diode emitting blue light. The method of claim 3, wherein A red frame for emitting the one frame to the red light emitting diode as a main light source; A green frame for emitting the green light emitting diodes as a main light source; And dividing the blue light emitting diode into a blue frame for emitting light as a main light source. The method of claim 4, wherein And the red light emitting diode, the green light emitting diode, and the blue light emitting diode are sequentially flashed. delete The method of claim 4, wherein When the determined video signal data is a video signal displaying a bright image, And illuminating the main light source for each of the red frame, green frame, and blue frame periods, and the sub light sources other than the main light source. The method of claim 7, wherein And the sub light sources are turned on at a predetermined brightness to increase the brightness of the image displayed on the liquid crystal panel. The method of claim 8, And the main light source increases in brightness in proportion to the brightness of the sub light sources. The method of claim 4, wherein When the determined video signal data is a video signal displaying a dark image, And only a main light source is turned on during each of the red, green, and blue frame periods. The method of claim 10, And the main light source is adjusted to a brightness lower than the brightness of the input original image signal data and is turned on. The method according to any one of claims 8, 9, 11, The brightness of the main light source and the sub light source is controlled by the voltage or current value supplied from the light source driving circuit. A driving method of a liquid crystal display device which divides one frame into a plurality of subframes and sequentially drives a plurality of light sources to display an image. Providing a timing controller for controlling the data driving circuit, the gate driving circuit, and the light source driving circuit; Storing image signal data input to the timing controller in a frame memory in units of frames; Determining the brightness of image signal data in one frame unit stored in the frame memory through image signal determination and a control unit; Adjusting the video signal data through the video signal discrimination and adjusting unit according to the video signal discrimination and the determination result of the control unit; Supplying a light source control signal to the light source driving circuit so as to correspond to the video signal data adjusted by the video signal discrimination and adjusting unit, Supplying the light source control signal The light source driving circuit divides and drives one frame into a red frame that emits a red light emitting diode as a main light source, a green frame that emits a green light emitting diode as a main light source, and a blue frame that emits a blue light emitting diode as a main light source. Supply, When the video signal data determined by the video signal discrimination and control unit is a video signal displaying a bright image, And illuminating the main light sources as the main light sources during the red frame, the green frame, and the blue frame period, as well as the sub light sources other than the main light sources. The method of claim 13, And each of the plurality of light sources emits one of color lights of red, green, and blue light. The method of claim 14, And the light sources are a plurality of red light emitting diodes, green light emitting diodes, and blue light emitting diodes emitting red, green, and blue light. delete The method of claim 15, And the red light emitting diode, the green light emitting diode, and the blue light emitting diode are sequentially flashed. The method of claim 17, And supplying the adjusted image signal data to the data driver. delete delete The method of claim 18, And lighting the main light source by increasing its brightness in proportion to the brightness of the sub light sources. The method of claim 18, When the video signal data determined by the video signal discrimination and control unit is a video signal displaying a dark image, And only the main light source is turned on during each of the red, green, and blue frame periods. The method of claim 22, And lighting the main light source by adjusting the brightness of the main light source to a brightness lower than that of the input original image signal data. The method according to any one of claims 21 and 23, The brightness of the main light source and the sub light source is controlled by the voltage or current value supplied from the light source driving circuit.

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