KR20170079435A - Liquid crystal display device - Google Patents

Abstract

The present invention relates to a liquid crystal display device. The present invention is characterized in that one frame period includes first to Pth (P is a positive integer of 2 or more) sub-frame periods, and the lighting period of each of the first light sources emitting light during the first sub- Emitting period of each of the light-emitting units. As a result, the present invention can greatly reduce the width of the color break-up, thereby improving color break-up.
In addition, the present invention is characterized in that one frame period includes first through P + 1 subframe periods and does not emit the first through P light sources during the P + 1 subframe period. That is, the present invention is characterized in that the (P-1) th frame period of the (N-1) th frame period and the And the (P + 1) th sub frame period existing between the first sub frame periods of the period can be used as a blank period. As a result, the present invention can significantly reduce the width of the color break-up in accordance with the movement of the line of sight of the viewer, thereby improving the color break-up.

Description

[0001] LIQUID CRYSTAL DISPLAY DEVICE [0002]

An embodiment of the present invention relates to a liquid crystal display device.

As the information society develops, the demand for display devices for displaying images is increasing in various forms. In recent years, various flat panel display devices such as a liquid crystal display (LCD), a plasma display panel (PDP), and an organic light emitting diode display device have been used . Among the flat panel display devices, the liquid crystal display device displays an image by controlling the electric field applied to the liquid crystal layer to modulate the light incident from the backlight unit.

A liquid crystal display device includes a display panel including gate lines, data lines, and pixels for displaying an image, a gate drive circuit for supplying gate signals to gate lines, and a source drive circuit And a timing controller for controlling the driving timings of the gate driving circuit and the source driving circuit. Each of the pixels modulates light incident from the backlight unit by driving liquid crystal in the liquid crystal layer by an electric field between a data voltage supplied to the pixel electrode and a common voltage supplied to the common electrode. The backlight unit includes light sources that emit a predetermined light when a driving current is supplied from the backlight driving circuit.

Liquid crystal displays typically display colors using red, green, and blue color filters. In recent years, instead of the red, green, and blue color filters, the backlight unit sequentially emits red light sources emitting red light, green light sources emitting green light, and blue light sources emitting blue light, A field sequential method has been proposed. The field sequential method divides one frame period into three sub frame periods, emits red light sources to emit red light during the first sub frame period, emits green light sources during the second sub frame period to emit green light And emits blue light sources during the third sub-frame period to display blue light. The field sequential method displays an image by a combination of red light in the first sub frame period, green light in the second sub frame period, and blue light in the third sub frame period.

However, in the field sequential method, when the object of the image displayed by the display panel moves, the viewer's line of sight moves along the moving direction of the object. As a result, the viewer may see a color break up (color break up). As a result, a problem that a viewer feels a drop in image quality of the liquid crystal display device may occur.

An embodiment of the present invention provides a field sequential liquid crystal display capable of improving color break up.

A liquid crystal display according to an embodiment of the present invention is divided into a display panel divided into a plurality of display blocks, a plurality of lighting blocks corresponding to a plurality of display blocks, P (P is a positive integer equal to or greater than 2) light sources. One frame period includes first through Pth sub frame periods. In the first to Pth sub frame periods, the first to P light sources sequentially emit light. The light emission period of each of the first light sources is shorter than the light emission period of each of the remaining light sources.

A liquid crystal display device according to an embodiment of the present invention is divided into a display panel divided into a plurality of display blocks and a plurality of lighting blocks corresponding to the plurality of display blocks, And a backlight unit including the P light sources. The one frame period includes the first to (P + 1) th sub frame periods. In the first to Pth sub frame periods, the first to P light sources sequentially emit light. The first through P light sources do not emit light during the (P + 1) th sub frame period.

The embodiment of the present invention is characterized in that one frame period includes first to Pth (P is a positive integer of 2 or more) sub-frame periods, and the lighting period of each of the first light sources emitting light during the first sub- Is shorter than the lighting period of each of the light sources emitting light in each of the frame periods. As a result, embodiments of the present invention can significantly reduce the width of color break-up, thereby improving color break-up.

In addition, the embodiment of the present invention supplies the modulated frame data obtained by modulating the frame data by adjusting the gray level values of the frame data as much as the lighting period of each of the first light sources is shortened during the first sub frame period, And supplies the original frame data during the periods. As a result, the embodiment of the present invention can compensate for the lowering of the luminance of the image displayed in the first sub frame period due to the reduction of the lighting period of each of the first light sources.

Also, the embodiment of the present invention emits blue light, green light, and red light in this order in the first to third sub frame periods of each of the (N-1) th to (N + 1) th frame periods. As a result, the embodiment of the present invention can further reduce the lighting period of the third light sources that emit blue light in the first sub frame period. As a result, the embodiment of the present invention can further reduce the width of the color break-up, thereby further improving the color break-up.

In addition, the embodiment of the present invention does not emit the first through P light sources during the (P + 1) th sub frame period in one frame period including the first through P + 1 sub frame periods. That is, in the embodiment of the present invention, the P-1 sub frame period of the (N-1) -th frame period and the first sub frame period of the N-th frame period, the The (P + 1) -th sub frame period existing between the first sub frame periods of the +1 frame period can be used as a blank period. As a result, the embodiment of the present invention can significantly reduce the width of the color break-up in accordance with the movement of the line of sight of the viewer, thereby improving the color break-up.

Further, in the embodiment of the present invention, as the lighting periods of all of the first through P light sources are shortened in each of the first through Pth sub frame periods, the modulation frame Data is supplied. As a result, in the embodiment of the present invention, the length of the first to Pth sub frame periods is shortened, so that the luminance of the image displayed by the display panel can be compensated for.

FIGS. 1A to 1C are exemplary diagrams showing the movement of an object during an Nth and (N + 1) -th frame periods in the conventional field sequential method and an image shown to a viewer.
FIG. 2 is an exemplary diagram for explaining color break-up according to movement of an object during N-1 th to (N + 1) th frame periods in a conventional field sequential method.
3 is a block diagram showing a liquid crystal display according to an embodiment of the present invention.
4 is a circuit diagram showing an example of the pixel of FIG.
5 is an exemplary view showing the blocks of the display panel and the blocks of the backlight unit for backlight scanning driving.
6A and 6B are diagrams illustrating an example of a histogram of frame data and modulation of frame data.
7 is an exemplary view for explaining a field sequential method of a liquid crystal display device according to an embodiment of the present invention.
8 is an exemplary diagram showing data addressing and lighting timing of the lighting blocks according to an embodiment of the present invention.
9 is an exemplary diagram showing the timing of turning on the backlight of the Q-th lighting block during the (N-1) th to (N + 1) -th frame periods.
10 is another exemplary diagram showing the backlight lighting timing of the Q-th lighting block during the (N-1) th to (N + 1) -th frame periods.
11 is an exemplary diagram showing data addressing and lighting timing of lighting blocks according to an embodiment of the present invention.
12 is another exemplary diagram showing the backlight lighting timing of the Q-th lighting block during the (N-1) th to (N + 1) -th frame periods.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

The shapes, sizes, ratios, angles, numbers, and the like disclosed in the drawings for describing the embodiments of the present invention are illustrative, and thus the present invention is not limited thereto. Like reference numerals refer to like elements throughout the specification. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

Where the terms "comprises," "having," "consisting of," and the like are used in this specification, other portions may be added as long as "only" is not used. Unless the context clearly dictates otherwise, including the plural unless the context clearly dictates otherwise.

In interpreting the constituent elements, it is construed to include the error range even if there is no separate description.

In the case of a description of the positional relationship, for example, if the positional relationship between two parts is described as 'on', 'on top', 'under', and 'next to' Or " direct " is not used, one or more other portions may be located between the two portions.

In the case of a description of a temporal relationship, for example, if the temporal relationship is described by 'after', 'after', 'after', 'before', etc., May not be continuous unless they are not used.

The first, second, etc. are used to describe various components, but these components are not limited by these terms. These terms are used only to distinguish one component from another. Therefore, the first component mentioned below may be the second component within the technical spirit of the present invention.

The terms "X-axis direction "," Y-axis direction ", and "Z-axis direction" should not be construed solely by the geometric relationship in which the relationship between them is vertical, It may mean having directionality.

It should be understood that the term "at least one" includes all possible combinations from one or more related items. For example, the meaning of "at least one of the first item, the second item and the third item" means not only the first item, the second item or the third item, but also the second item and the second item among the first item, May refer to any combination of items that may be presented from more than one.

It is to be understood that each of the features of the various embodiments of the present invention may be combined or combined with each other, partially or wholly, technically various interlocking and driving, and that the embodiments may be practiced independently of each other, It is possible.

FIGS. 1A to 1C are exemplary diagrams showing the movement of an object during an Nth and (N + 1) -th frame periods and an image shown to a viewer in a conventional field sequential liquid crystal display. FIG. 1A shows an image displayed by frame data in the Nth frame period, and FIG. 1B shows an image displayed by frame data in the (N + 1) frame period. 1C shows an image that is displayed to the viewer in accordance with the movement of the object OBJ of the picture during the Nth and (N + 1) -th frame periods. In FIGS. 1A to 1C, for convenience of explanation, the object OBJ is a circle represented by white tones, and the background is represented by black tones. The object OBJ can be defined as an object of an image displayed on the display panel.

When the object OBJ moves from one side of the image to the center during the Nth and (N + 1) -th frame periods as shown in Figs. 1A and 1B, Up (color break up, CBU). That is, the viewer can not properly view the object (CBU) displayed on the image due to the color break-up (CBU), so that a problem that the quality of the image is deteriorated may occur. Hereinafter, the reason why the color break-up (CBU) occurs when the object OBJ moves during the frame periods in the conventional field sequential liquid crystal display device will be described in detail with reference to FIG.

FIG. 2 is an exemplary diagram for explaining color break-up according to movement of an object during N-1th to (N + 1) -th frame periods in a conventional field sequential liquid crystal display. In FIG. 2, the X-axis direction represents the moving direction of the object, and the Y-axis direction represents the time flow. In FIG. 2, only the (N-1) th to (N + 1) th frame periods F (N-1), F (N) and F (N + 1) are shown for convenience of explanation. In Fig. 2, an arrow indicates a line of sight (VE) of the viewer.

Referring to FIG. 2, each of the (N-1) th to (N + 1) th frame periods F (N-1), F SF1, SF2, and SF3. 2, the red light sources emit light during the first sub frame period SF1 of the (N-1) th to (N + 1) th frame periods F (N-1), F , Green light sources emit light during the second sub frame period (SF2), and blue light sources emit during the third sub frame period (SF3). The light emission periods (DUTY) of red light sources, green light sources, and blue light sources are the same.

(OBJ_MW) for the (N-1) th to (N + 1) th frame periods F (N-1), F Respectively. In this case, the line of sight VE of the viewer perceives moving along the moving direction of the object. Further, the red, green, and blue light sources are divided into first to third sub-frames (N-1 to N + 1) of each of the N-1 to N + 1 frame periods F And sequentially emits light during the frame periods SF1, SF2, and SF3. Accordingly, the viewer's line VE sequentially recognizes red (R), green (G), and blue (B) during the sub-frame periods of one frame period. Thus, the viewer feels color break-up as shown in Fig.

Color breakup occurs on both sides of the plateau width PW as shown in Fig. The plateau width (PW) refers to the width at which the object is viewed properly by the combination of red, green, and blue light, and narrows due to color break-up. According to the VE movement of the viewer, only a combination of red light and green light except for blue light is visible on one side of the object, and only the combination of green advertisement blue light except red light is visible on the other side of the object. As a result, red shift occurs on one side of the plateau width PW, and blue shift occurs on the other side.

The width of the object (PIW) recognized by the viewer is the sum of the width of the color breakup (CBU_W) generated on both sides of the plateau width (PW) and the plateau width (PW). As the width CBU_W of the color break-up becomes wider, the width of the object (PIW) recognized by the viewer can be widened.

As described above, there is a problem that the color break-up is visually recognized in accordance with the movement of the viewer's line of sight (VE). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention capable of improving color break-up will be described in detail with reference to the accompanying drawings.

3 is a block diagram showing a liquid crystal display according to an embodiment of the present invention. 3, a liquid crystal display 100 according to an embodiment of the present invention includes a display panel 110, a display panel driver, a timing controller 140, a frame data modulation A backlight unit 210, and a backlight driving unit 220, as shown in FIG. The display panel driving unit includes a gate driving unit 120 and a data driving unit 130 and drives the display panel 110 so that the display panel 110 displays an image under the control of the timing controller 140.

The display panel 110 includes a lower substrate 111, an upper substrate 112, and a liquid crystal layer LC formed therebetween. The data lines D1 to Dm and the gate lines G1 to Gn are disposed on the lower substrate 111 of the display panel 110 so as to intersect with each other. Pixels P are arranged in a matrix in regions formed by intersections of the data lines D1 to Dm and the gate lines G1 to Gn. Each of the pixels P may be connected to any one of the data lines D1 to Dm and the gate lines G1 to Gn. Accordingly, the pixel P receives the data voltage of the data line when the gate signal is supplied to the gate line, and emits light with a predetermined brightness according to the supplied data voltage.

For example, each of the pixels P may include a transistor T, a pixel electrode PE, a common electrode CE, and a storage capacitor Cst as shown in FIG. The transistor T may be a thin film transistor formed by a semiconductor process. The transistor T is connected to the gate of the gate line Gk at a jth (j is a positive integer satisfying 1? J? M) in response to the gate signal of the k-th gate line Gk (k is a positive integer satisfying 1? And supplies the data voltage of the data line Dj to the pixel electrode PE. Each of the pixels P drives the liquid crystal of the liquid crystal layer LC by an electric field generated by a potential difference between a data voltage supplied to the pixel electrode PE and a common voltage supplied to the common electrode CE The amount of light transmitted from the backlight unit can be adjusted. The common electrode CE is supplied with a common voltage from the common line CL. The storage capacitor Cst is provided between the pixel electrode PE and the common electrode CE to maintain a constant voltage difference between the pixel electrode PE and the common electrode CE.

A black matrix and color filters may be formed on the upper substrate 112 of the display panel 110. However, when the liquid crystal display device 100 is formed by a COT (color filters on tft array) method, a black matrix and color filters may be formed on a lower substrate.

The common electrode CE is formed on the upper substrate 112 in the case of a vertical field driving method such as TN (Twisted Nematic) mode and VA (Vertical Alignment) And may be formed on the lower substrate 111 together with the pixel electrode PE in the case of a horizontal field driving method such as a field switching mode. The liquid crystal display of the present invention can be implemented in any liquid crystal mode as well as a TN mode, a VA mode, an IPS mode, and an FFS mode. An upper polarizer 112a is attached to the upper substrate 112 of the display panel 110 and a lower polarizer 111a is attached to the lower substrate 111. [ An alignment film for setting a pre-tilt angle of the liquid crystal is formed.

The gate driver 120 receives the gate control signal GCS from the timing controller 140. The gate driver 120 generates gate signals according to the gate control signal GCS and supplies the gate signals to the gate lines G1 to Gn.

The gate drive circuit 120 may include a plurality of gate drive integrated circuits (hereinafter referred to as "ICs "). Each of the gate drive ICs may be fabricated as a driving chip. Each of the gate drive ICs may be mounted on a gate flexible film, and each of the gate flexible films may be implemented as a tape carrier package or a chip on film. The chip-on film may include a base film such as polyimide and a plurality of conductive lead wires provided on the base film. Each of the gate flexible films may be bent or bent. The gate flexible films can be attached on the lower substrate by a tape automated bonding (TAB) method using an anisotropic conductive film, whereby the gate drive ICs can be connected to the gate lines G1 to Gn .

Alternatively, the gate driver 120 may be formed in a non-display region of the display panel 110 by a gate driver in panel (GIP) scheme. The non-display area indicates an area where no image is displayed in the peripheral portion of the display area PA.

The data driver 130 is connected to the data lines D1 to Dm. The data driver 130 receives the frame data DATA or the modulation frame data DATA and the data control signal DCS from the timing controller 140 and outputs the frame data DATA or And converts the modulated frame data (DATA ') into analog data voltages. The data driver 130 supplies the data voltages to the data lines D1 to Dm.

The data driver 130 may include at least one source driver IC. The source drive IC may be made of a drive chip and mounted on the source flexible film. The source flexible film may be implemented as a tape carrier package or a chip-on film. Each of the source flexible films can be bent or bent. The source flexible films can be attached on the lower substrate in a TAB manner using an anisotropic conductive film.

The timing controller 140 receives frame data (DATA) and timing signals (TS) from an external system board. In addition, the timing controller 140 receives the modulation frame data (DATA ') from the frame data modulator 150. The frame data indicates digital video data corresponding to one frame period. The timing signals TS may include a vertical sync signal, a horizontal sync signal, a data enable signal, and a dot clock.

The timing controller 140 divides one frame period into a plurality of sub frame periods to drive in a field sequential manner. The timing controller 140 divides one frame period into P or P + 1 subframe periods when the backlight unit 210 includes light sources for displaying P (P is a positive integer of 2 or more) colors can do. For example, if the backlight unit 210 includes light sources that display three colors, such as red, green, and blue light sources 211, 212, and 213, as shown in FIG. 3, The frame period can be divided into three or four sub frame periods. Hereinafter, the backlight unit 210 includes red, green, and blue light sources 211, 212, and 213 for convenience of explanation.

The timing controller 140 can set the frame frequency so that the gate driver 120 and the data driver 130 can be driven at a high speed of 180 Hz when one frame period is divided into three subframe periods. Alternatively, the timing controller 140 may set the frame frequency so that the gate driver 120 and the data driver 130 can be driven at a high frequency of 240 Hz to 360 Hz when one frame period is divided into four subframe periods.

The timing controller 140 generates a gate control signal GCS for controlling the operation timing of the gate driver 120 based on the timing signals TS and a data control signal for controlling the operation timing of the data driver 130 DCS). The timing controller 140 supplies the frame data DATA or the modulation frame data DATA and the data control signal DCS to the data driver 130 and supplies the gate control signal GCS to the gate driver 120 do.

In addition, the timing controller 140 supplies the first backlight data BD1 so that the red light sources 211 emit light during the first sub frame period of the frame period. The first backlight data BD1 may include information on the lighting time point, the light-off time point, and the duty ratio of the red light sources 211. [ The timing controller 140 supplies the second backlight data BD2 so that the green light sources 212 emit light during the second sub frame period of the frame period. The second backlight data BD2 may include information on the lighting time point, the light-off time point, and the duty ratio of the green light sources 212. [ The timing controller 140 supplies the third backlight data BD3 so that the blue light sources 213 emit light during the third sub frame period of the frame period. The third backlight data BD3 may include information on the light-on timing, the light-off timing, and the duty ratio of the blue light sources 213. [ The duty ratio represents the lighting ratio of the light source as shown in Equation (1).

In Equation (1), DR (%) is the duty ratio, Ton is the lighting time of the light source during the sub frame period, and Toff is the off time of the light source during the sub frame period.

The frame data modulator 150 receives frame data (DATA) from an external system board. The frame data modulator 150 modulates the frame data (DATA) to generate modulated frame data (DATA '). The frame data modulator 150 modulates the frame data DATA to compensate for the luminance reduction due to the duty ratio adjustment when there is the duty ratio adjustment of some or all of the first to third light sources, DATA ').

The frame data modulator 150 calculates the histogram of the frame data (DATA) as shown in FIG. 6A. In FIG. 6A, the frame data DATA is 8-bit data having gray level values from 0 to 255, mainly.

The frame data modulator 150 modulates the frame data (DATA) based on the calculated histogram as shown in FIG. 6B. 6B, the frame data modulator 150 adjusts the gray scale values of the frame data DATA up to the duty ratio of the modulated frame by adjusting the duty ratio of the first through third light sources, Data (DATA ') can be generated. In this case, since the gray level values of the modulation frame data DATA 'are distributed in a higher gray level range than the gray level values of the original frame data (DATA), the brightness of the image displayed by the modulation frame data (DATA' May be higher than the luminance of the image displayed by the data (DATA). The duty ratio of some or all of the first to third light sources may be stored in the memory of the frame data modulating unit 150. [

That is, the embodiment of the present invention adjusts the tone values of the frame data (DATA) upward as the duty ratio is decreased when the duty ratio of some or all of the first to third light sources is adjusted. Accordingly, the embodiment of the present invention can compensate for the luminance reduction due to the duty ratio adjustment.

The backlight unit 210 includes light sources 211, 212, and 213 for illuminating the display panel 110 with light. For example, the backlight unit 210 may include red light sources 211 for emitting red light, green light sources 212 for emitting green light, and blue light sources 213 for emitting blue light. have. Each of the red, green, and blue light sources 211, 212, and 213 may be mounted on the light source circuit board. Each of the red, green, and blue light sources 211, 212, and 213 may be a light emitting diode (LED). The red light sources 211 emit light according to the first driving current DC1 supplied from the backlight driving unit 220 and the green light sources 212 emit light according to the second driving current DC2, Emit light in accordance with the third driving current DC3.

The backlight unit 210 may be implemented as a direct type or an edge type. The direct type backlight unit 210 has a structure in which a plurality of optical sheets and a diffusion plate are stacked under the display panel 110 and a plurality of light sources 211, 212, and 213 are disposed under the diffusion plate. The edge type backlight unit 210 has a structure in which a plurality of optical sheets and a light guide plate are stacked under the display panel 110 and a plurality of light sources are disposed on a side surface of the light guide plate.

The backlight unit 210 may be divided into a plurality of lighting blocks BBL1 to BBL4 as shown in FIG. The lighting blocks BBL1 to BBL4 of the backlight unit 210 may correspond to the display blocks PBL1 to PBL4 of the display panel 110. [ That is, the light of each of the lighting blocks BBL1 to BBL4 of the backlight unit 210 can be irradiated to each of the display blocks PBL1 to PBL4 of the display panel 110 corresponding to each other. For example, the light of the first lighting block BBL1 is irradiated to the first display block PBL1, the light of the second lighting block BBL2 is illuminated to the second display block PL2, The light from the fourth block BLL3 may be irradiated to the third display block PL3 and the light from the fourth lightening block BBL4 may be irradiated to the fourth display block PL4.

The backlight driver 220 receives the first through third backlight data BD1, BD2, and BD3 from the timing controller 140. The backlight driver 220 generates a first driving current DC1 for emitting the red light sources 211 according to the first backlight data BD1 and supplies the first driving current DC1 to the red light sources 211. [ The backlight driver 220 generates a second driving current DC2 for emitting the green light sources 212 according to the second backlight data BD2 and supplies the second driving current DC2 to the green light sources 212. [ The backlight driver 220 generates a third driving current DC3 for emitting the blue light sources 213 according to the third backlight data BD3 and supplies the third driving current DC3 to the blue light sources 213. [ The backlight driver 220 emits red light sources 211 during the first sub frame period of each of the frame periods and emits green light sources 212 during the second sub frame period, And supplies the first to third driving currents DC1 to DC3 so that the light sources 213 emit light.

The backlight unit 210 supplies the red light RL to the display panel 110 using the red light sources 211 during the first sub frame period of each of the frame periods as shown in FIG. The green light GL is supplied to the display panel 110 using the green light sources 212 and the blue light BL is supplied to the display panel 110 using the blue light sources 213 during the third sub- . The display panel 110 displays the color image PL according to the combination of the red light RL, the green light GL and the blue light BL sequentially input during the first to third sub frame periods . That is, in the embodiment of the present invention, as shown in FIG. 7, one frame period is divided into a plurality of sub-frame periods, and a plurality of sub-frame periods are sequentially driven in a field sequential manner .

8 is an exemplary diagram showing data addressing and lighting timing of the lighting blocks according to an embodiment of the present invention. 8, the horizontal axis represents time t, and the arrows represent data addressing DA for which the data voltages are supplied.

In FIG. 8, first through third sub frame periods of the Nth frame period are illustrated for convenience of explanation, and driving at 180 Hz is exemplified. In FIG. 8, for convenience of description, it is illustrated that each of the lighting blocks BBL1 to BBL4 of the backlight unit 210 includes the first to third light sources. The first light sources are red light sources emitting red light RL and the second light sources are green light sources emitting green light GL and the third light sources are blue light sources emitting blue light BL .

Referring to FIG. 8, each of the first through third sub frame periods SF1, SF2, and SF3 represents a period from the start of data addressing (DA) to the end of data display on the display panel 110.

The first light sources emitting red light RL emit light during the first sub frame period SF1. The lighting blocks BBL1 to BBL4 of the backlight unit 210 are driven in a scanning backlight manner which sequentially emits light. That is, the first light sources of the first lighting block BBL1 emit light in the first display block PBL1 of the display panel 110 during data addressing (DA), and the data display DA is applied to the second display block PBL2. And the first light sources of the second turn-on block (BBL2) emit light. The first light sources of the third lighting block BBL3 emit light in the third display block PBL3 of the display panel 110 during the data addressing DA and data addressing DA is applied to the fourth display block PBL4. The first light sources of the fourth on-off block BBL4 emit light. Each of the first light sources emits light only during the first sub frame period SF1, and goes out before the data addressing DA of the second sub frame period SF2.

And the second light sources emitting the green light GL during the second sub frame period SF2 emit light. The lighting blocks BBL1 to BBL4 of the backlight unit 210 are driven in a scanning backlight manner which sequentially emits light. That is, the second light sources of the first lighting block BBL1 emit light in the first display block PBL1 of the display panel 110 during the data addressing (DA), and the data addressing DA is applied to the second display block PBL2. And the second light sources of the second turn-on block (BBL2) emit light. When the second light sources of the third lighting block BBL3 emit light in the third display block PBL3 of the display panel 110 during data addressing DA and the second light sources of the third lighting block BBL3 emit light during the data addressing DA And the second light sources of the fourth lighting block BBL4 emit light. Each of the second light sources emits light only during the second sub frame period (SF2), and goes out before the data addressing (DA) of the third sub frame period (SF3).

And the third light sources emitting the blue light BL emit light during the third sub frame period SF3. The lighting blocks BBL1 to BBL4 of the backlight unit 210 are driven in a scanning backlight manner which sequentially emits light. That is, the third light sources of the first lighting block BBL1 emit light in the first display block PBL1 of the display panel 110 during data addressing (DA), and the data display DA is applied to the second display block PBL2. And the third light sources of the second turn-on block (BBL2) emit light. The third light sources of the third lighting block BBL3 emit light in the third display block PBL3 of the display panel 110 during the data addressing DA and the data addressing DA is applied to the fourth display block PBL4. And the third light sources of the fourth turn-on block (BBL4) emit light. Each of the third light sources emits light only during the third sub frame period SF3, and is extinguished before data addressing DA of the first sub frame period SF1 of the next frame period.

The light emitting period d2 of each of the second light sources emitting light during the second sub frame period SF2 and the light emitting period d2 of each of the third light sources emitting light during the third sub frame period SF3 are substantially equal to each other . The lighting period d1 (or the duty ratio) of each of the first light sources emitting light during the first sub frame period SF1 is different from the second light sources emitting light during the second sub frame period SF2 and the second light sources emitting light during the third sub frame period (Or duty ratio) of each of the third light sources that emit light during the first to third light sources SF1 to SF3. Thus, the luminance of the image displayed in the first sub-frame period SF1 can be lower than the luminance of the image displayed in each of the second and third sub-frame periods SF2 and SF3. Therefore, the modulation frame data (DATA ') generated by the frame data modulator 150 during the first sub frame period SF1 is supplied during the first sub frame period SF1, and the second and third sub frame periods (DATA) during the frame period (SF2, SF3). The modulation frame data DATA 'is obtained by adjusting the gray level values of the frame data DATA upward by increasing the lighting period d1 of each of the first light sources in the first sub frame period SF1, It is modulated data. Therefore, the luminance degradation of the image displayed in the first sub frame period (SF1) due to the decrease of the lighting period (d1) of each of the first light sources can be compensated.

Meanwhile, in order to improve the color break-up, an embodiment of the present invention is characterized in that the light emitting period d1 (or the duty ratio) of each of the first light sources emitting light during the first sub frame period SF1 is defined as a second sub frame period (Or the duty ratio) of the second light sources emitting light during the first sub-frame period SF2 and the third light sources emitting light during the third sub-frame period SF3. A detailed description thereof will be given later with reference to FIG.

9 is an exemplary diagram showing the timing of turning on the backlight of the Q-th lighting block during the (N-1) th to (N + 1) -th frame periods. In FIG. 9, the Q (Q is a positive integer) lighting block indicates one of the lighting blocks of the backlight unit 210. The X axis direction indicates the direction of movement of the object, and the Y axis direction indicates the time flow. In FIG. 9, only the (N-1) th to (N + 1) th frame periods F (N-1), F (N) and F (N + 1) are shown for convenience of explanation. In Fig. 9, an arrow indicates a line of sight (VE) of the viewer.

Referring to FIG. 9, each of the (N-1) th to (N + 1) th frame periods F (N-1), F SF1, SF2, and SF3. The first light sources for displaying the red light RL are arranged in the first sub frame of each of the (N-1) th to (N + 1) th frame periods F (N-1), F The second light sources emitting green for the period SF1 emit light for the second sub frame period SF2 and the third light sources for displaying the blue light BL emit light for the third sub frame period SF3.

(OBJ_MW) for the (N-1) th to (N + 1) th frame periods F (N-1), F Respectively. In this case, the line of sight VE of the viewer perceives moving along the moving direction of the object. Further, the red, green, and blue light sources are divided into first to third sub-frames (N-1 to N + 1) of each of the N-1 to N + 1 frame periods F And sequentially emits light during the frame periods SF1, SF2, and SF3. Accordingly, the viewer's line VE sequentially recognizes red (R), green (G), and blue (B) during the sub-frame periods of one frame period.

The embodiment of the present invention is characterized in that the second light sources emitting light during the second sub frame period (SF2) and the second light sources emitting light during the first sub frame period (SF1) (Or the duty ratio) of each of the third light sources emitting light during the three sub-frame periods SF3. Since the color breakup increases in proportion to the lighting period d1 of the first light sources during the first sub frame period SF1, the embodiment of the present invention is characterized in that the lighting period d1 of the first light sources during the first sub frame period SF1 ), The width (CBU_W) of the color break-up can be greatly reduced and the plateau width (PW) can be greatly increased. The plateau width (PW) indicates the width at which the object is properly viewed by a combination of red, green, and blue light. That is, as shown in FIG. 9, most of the width (PIW) of the object recognized by the viewer corresponds to the plate width PW. As a result, embodiments of the present invention can improve color break-up.

10 is another exemplary diagram showing the timing of turning on the backlight of the P-th block during the (N-1) th to (N + 1) -th frame periods. In FIG. 10, the Q (Q is a positive integer) lighting block indicates one of the lighting blocks of the backlight unit 210. In FIG. 10, the X-axis direction represents the moving direction of the object, and the Y-axis direction represents the time flow. In FIG. 10, only the (N-1) th to (N + 1) th frame periods F (N-1), F (N) and F (N + 1) are shown for convenience of explanation. In Fig. 10, an arrow indicates a line of sight (VE) of the viewer.

In FIG. 10, the third light sources for displaying the blue light (BL) are arranged in the (N + 1) th to N + 1th frame periods F (N-1), F The second light sources for emitting the green light GL emit light during the second sub frame period SF2 and the third light sources for displaying the red light RL emit light during the sub frame period SF1, Is substantially the same as that described with reference to Fig. 9, except that it emits light during the period SF3. That is, in FIG. 9, the first to third sub frame periods SF1 (N-1) to F (N + 1)) of the (N-1) th to (N + 1) th to (N + 1) th frame periods (red, green, and blue in FIG. 10) Green light GL and red light RL in the first to third sub frame periods of each of the sub-frame periods F (N-1), F (N-1), F In order.

A person usually does not recognize blue light (BL) more than red light (RL). Therefore, when the third light sources emit blue light BL during the first sub-frame period SF1, even if the lighting period d1 'of the third light sources is reduced, the viewer is aware of the reduction of the blue light BL can not do. Therefore, in the embodiment of the present invention, as shown in FIG. 10, during the first sub-frame period SF1, the lighting period d1 'of the third light sources is changed to the first sub- Can be further reduced compared with the lighting period (d1). As a result, the embodiment of the present invention can further reduce the width (CBU_W) of the color break-up, thereby further improving the color break-up.

11 is an exemplary diagram showing data addressing and lighting timing of light sources according to an embodiment of the present invention. In Fig. 11, the horizontal axis represents time t, and the arrows represent data addressing DA for which the data voltages are supplied.

In FIG. 11, the first to fourth sub frame periods of the Nth frame period are exemplified for convenience of explanation, and the high speed driving of 240 Hz or more is exemplified. In FIG. 11, the lighting blocks BBL1 to BBL4 of the backlight unit 210 include the first to third light sources for convenience of explanation. The first light sources are red light sources emitting red light RL and the second light sources are green light sources emitting green light GL and the third light sources are blue light sources emitting blue light BL .

Referring to FIG. 11, each of the first through fourth sub frame periods SF1, SF2, SF3, and SF4 represents a period from the start of data addressing (DA) to the end of data display on the display panel 110 .

The first to third sub frame periods SF1, SF2, and SF3 are substantially the same as those described in conjunction with Fig. 8, except that the first to third light sources are lit in the same lighting period (d). Therefore, the detailed description of the first through third sub frame periods SF1, SF2, and SF3 is omitted in FIG.

The first to third light sources do not emit light during the fourth sub frame period SF4. Black frame data may be addressed during the fourth sub frame period SF4, or no frame data may be addressed.

The length of the fourth sub frame period SF4 may be substantially equal to the length of each of the first through third sub frame periods SF1, SF2, SF3. Alternatively, the length of the fourth sub frame period SF4 may be longer than the length of each of the first to third sub frame periods SF1, SF2, SF3. Since the width of the color break-up CBU_W can be reduced as the length of the fourth sub frame period SF4 becomes longer, the color break-up can be improved. However, as the length of the fourth sub frame period SF4 becomes longer, the lengths of the first through third sub frame periods SF1, SF2, and SF3 become shorter, so that the first through third sub frame periods SF1 and SF2 , And SF3). Therefore, the length of the fourth sub frame period SF4 can be appropriately set through a preliminary experiment in consideration of color break-up improvement and high-speed frequency operation.

Also, the length of the first to third sub frame periods SF1, SF2, and SF3 is shortened due to the fourth sub frame period SF4. Accordingly, the luminance of the image displayed by the display panel 110 can be lowered. Accordingly, the modulation frame data (DATA ') generated by the frame data modulator 150 is supplied to each of the first to third sub frame periods (SF1, SF2, SF3). The modulation frame data DATA 'is data obtained by modulating the frame data DATA by adjusting the gray level values of the frame data DATA upwards as the lighting period d of all of the first to third light sources is shortened. Therefore, in the embodiment of the present invention, the length of the first to third sub-frame periods SF1, SF2, and SF3 is shortened to compensate for the brightness of the image displayed on the display panel 110 being lowered.

On the other hand, the embodiment of the present invention does not emit the first to third light sources in the fourth sub frame period SF4 to improve color break-up. A detailed description thereof will be given later with reference to FIG.

12 is another exemplary diagram showing the backlight lighting timing of the P-th block during the (N-1) th to (N + 1) -th frame periods. In FIG. 12, the Q (Q is a positive integer) lighting block indicates one of the lighting blocks of the backlight unit 210. The X axis direction indicates the direction of movement of the object, and the Y axis direction indicates the time flow. In FIG. 12, only the (N-1) th to (N + 1) th frame periods F (N-1), F (N) and F (N + 1) are shown for convenience of explanation. In Fig. 12, an arrow indicates a line of sight (VE) of the viewer.

Referring to FIG. 12, each of the (N-1) th to (N + 1) th frame periods F (N-1), F SF1, SF2, SF3, and SF4. The first light sources for displaying the red light RL are arranged in the first sub frame of each of the (N-1) th to (N + 1) th frame periods F (N-1), F The second light sources emitting green for the period SF1 emit light for the second sub frame period SF2 and the third light sources for displaying the blue light BL emit light for the third sub frame period SF3. The lighting period (d) of the first to third light sources is the same. The first to third light sources are driven during the fourth sub frame period SF4 of each of the (N-1) th to (N + 1) th frame periods F (N-1), F It does not emit light.

And that the object OBJ moves to a predetermined moving range OBJ_MW during the (N-1) th to (N + 1) -th frame periods. In this case, the line of sight VE of the viewer perceives moving along the moving direction of the object. Further, the red, green, and blue light sources are divided into first to third sub-frames (N-1 to N + 1) of each of the N-1 to N + 1 frame periods F And sequentially emits light during the frame periods SF1, SF2, and SF3. Accordingly, the viewer's line VE sequentially recognizes red (R), green (G), and blue (B) during the sub-frame periods of one frame period.

The embodiment of the present invention does not emit the first to third light sources during the fourth sub frame period SF4 as shown in FIG. That is, between the third sub frame period SF3 of the (N-1) th frame period F (N-1) and the first sub frame period SF1 of the Nth frame period F (N) The fourth sub frame period SF4 is provided between the third sub frame period SF3 of the period F (N) and the first sub frame period SF1 of the (N + 1) -th frame period F (N + Is inserted as a blank period. Therefore, in the embodiment of the present invention, the third sub frame period SF3 and the Nth frame period F (N (N-1)) of the (N-1) 1) of the (N + 1) -th frame period F (N + 1) in the Nth frame period F (N) and the third sub frame period SF3 of the Nth frame period F The period between the first sub frame periods SF1 can be increased. Therefore, in the embodiment of the present invention, as shown in FIG. 12, the width CBU_W of the color break-up according to the movement of the viewer's line VE can be greatly reduced, and the plateau width PW can be greatly increased . The plateau width (PW) indicates the width at which the object is properly viewed by a combination of red, green, and blue light. That is, as shown in FIG. 12, most of the width (PIW) of the object recognized by the viewer corresponds to the plate width PW. As a result, embodiments of the present invention can improve color break-up.

Although the embodiments of the present invention have been described in detail with reference to the accompanying drawings, it is to be understood that the present invention is not limited to those embodiments and various changes and modifications may be made without departing from the scope of the present invention. . Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. Therefore, it should be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of protection of the present invention should be construed according to the claims, and all technical ideas within the scope of equivalents should be interpreted as being included in the scope of the present invention.

100: liquid crystal display device 110: display panel
120: Gate driver 130: Data driver
140: timing controller 150: frame data modulation unit
210: backlight unit 211: red light sources
212: green light sources 213: blue light sources
220: backlight driver

Claims (10)

A display panel divided into a plurality of display blocks; And
Wherein each of the plurality of lit blocks comprises a backlight unit including first through to Pth (P is a positive integer equal to or greater than 2) light sources,
1 frame period includes first through Pth sub frame periods, the first through P light sources sequentially emit light in the first through Pth sub frame periods,
Wherein the light emission period of each of the first light sources is shorter than the light emission period of each of the remaining light sources. The method according to claim 1,
And the light emission periods of the remaining light sources are the same. The method according to claim 1,
A display panel driver for driving the display panel; And
Further comprising a frame data modulating section for modulating frame data by adjusting the gray level values of the frame data upward and outputting the modulated frame data to the timing controller,
Wherein the timing controller supplies the modulation frame data to the display panel driver during a first sub frame period and supplies the frame data to the display panel driver during a remaining sub frame period. A display panel divided into a plurality of display blocks; And
Wherein the plurality of lighting blocks are divided into a plurality of lighting blocks corresponding to the plurality of display blocks, each of the plurality of lighting blocks includes a backlight unit including first through P light sources,
1 frame periods include first through P + 1 sub frame periods, the first through P light sources sequentially emit light in the first through Pth sub frame periods, and during the P + 1 sub frame period Wherein the first to Pth light sources do not emit light. 5. The method of claim 4,
And the light emission periods of the first through P light sources are the same. 5. The method of claim 4,
And the length of the (P + 1) th sub frame period is the same as the length of each of the first to Pth sub frame periods. 5. The method of claim 4,
And the length of the (P + 1) -th sub-frame period is longer than the length of each of the first to P-th sub frame periods. 5. The method of claim 4,
A display panel driver for driving the display panel; And
Further comprising a frame data modulating section for modulating frame data by adjusting the gray level values of the frame data upward and outputting the modulated frame data to the timing controller,
Wherein the timing controller supplies the modulation frame data to the display panel driver during the first to Pth sub frame periods. The method according to claim 1 or 4,
And the plurality of lit blocks sequentially emit light in each of the first to Pth sub frame periods. The method according to claim 1 or 4,
When the first to Pth light sources are red light sources that emit red light, green light sources that emit green light, and blue light sources that emit blue light, the order of blue light sources, green light sources, and red light sources In the liquid crystal display device.

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