Display device performing local dimming

A display device includes a backlight unit including light source rows, each of the light source rows including light source blocks, a display panel configured to display an image by transmitting light emitted by the backlight unit, a panel driver configured to drive the display panel, and a backlight driver configured to drive the backlight unit. The backlight driver is configured to perform a vertical direction scan operation that sequentially select the light source rows and a horizontal direction sequential driving operation that sequentially drives the light source blocks included in a selected light source row of the light source rows.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority under 35 USC § 119 to Korean Patent Application No. 10-2019-0092272, filed on Jul. 30, 2019 in the Korean Intellectual Property Office (KIPO), the disclosure of the Korean Patent Application is incorporated herein in its entirety by reference.

BACKGROUND

Embodiments of the present inventive concept relate to display devices, and more particularly to display devices performing local dimming.

2. Description of the Related Art

In a display device, such as a liquid crystal display (LCD) device, luminance of the display device is determined by a product of luminance of a backlight unit and light transmittance of liquid crystals depending on image data. The LCD device may employ a backlight dimming method for the purpose of increasing a contrast ratio and reducing power consumption. The backlight dimming method controls backlight luminance and compensates image data by analyzing an input image and adjusting a dimming value based on the analysis. For example, to reduce power consumption, the backlight dimming method may reduce the backlight luminance by decreasing a dimming value (or a duty), and may increase the luminance through data compensation. Thus, power consumption of the backlight unit may be reduced.

A light emitting diode (LED) backlight unit using LEDs as a light source has been used for the backlight unit. The LEDs may boast of high luminance and low power consumption, compared with conventional lamps. Because the LEDs of the LED backlight unit allow for location-based control, the LEDs may be driven by local dimming According to the local dimming technology, the LED backlight unit may be divided into light source blocks and luminance may be controlled on a block-by-block basis. Further, in the local dimming method, local dimming values (or duties) may be determined by analyzing image data on a block basis, and the image data may be compensated based on the local dimming values. Accordingly, the contrast ratio may be increased, and the power consumption may be decreased.

In a conventional display device, to reduce after images or motion blurring, light source rows of the backlight unit are sequentially driven on a row-by-row basis when the local dimming is performed. However, a waterfall phenomenon where a horizontal line image having relatively high or low luminance exists or gradually moves may be caused by the sequential driving of the light source rows.

SUMMARY

Some example embodiments provide a display device capable of preventing or reducing a waterfall phenomenon when local dimming is performed.

According to example embodiments, there is provided a display device including a backlight unit including a plurality of light source rows, each of the plurality of light source rows including a plurality of light source blocks, a display panel configured to display an image by transmitting light emitted by the backlight unit, a panel driver configured to drive the display panel, and a backlight driver configured to drive the backlight unit. The backlight driver performs a vertical direction scan operation that sequentially selects the plurality of light source rows and a horizontal direction sequential driving operation that sequentially drives the plurality of light source blocks included in a selected one of the plurality of light source rows.

In example embodiments, to perform the vertical direction scan operation, the backlight driver may sequentially select one of the plurality of light source rows per first time.

In example embodiments, the first time may be determined by dividing a frame time by a number of the plurality of light source rows.

In example embodiments, to perform the horizontal direction sequential driving operation, the backlight driver may sequentially drive one of the plurality of light source blocks included in the selected one of the plurality of light source rows per second time.

In example embodiments, the second time may be determined by dividing a latency time from a data input time point to an image display time point by a number of the plurality of light source blocks included in each of the plurality of light source rows.

In example embodiments, the plurality of light source rows may include a first light source row and a second light source row, and the backlight driver may initiate the horizontal direction sequential driving operation for the second light source row before the horizontal direction sequential driving operation for the first light source row is completed.

In example embodiments, each of the plurality of light source rows may include first through M-th light source blocks, where M is an integer greater than 1. To perform the horizontal direction sequential driving operation, the backlight driver may sequentially drive the first through M-th light source blocks included in the selected one of the plurality of light source rows in a first horizontal direction from the first light source block to the M-th light source block in an odd-numbered frame, and may sequentially drive the first through M-th light source blocks included in the selected one of the plurality of light source rows in a second horizontal direction from the M-th light source block to the first light source block in an even-numbered frame.

According to example embodiments, there is provided a display device including a backlight unit including a plurality of light source rows, each of the plurality of light source rows including a plurality of light source blocks, a display panel configured to display an image by transmitting light emitted by the backlight unit, a panel driver configured to drive the display panel, and a backlight driver configured to drive the backlight unit. The backlight driver divides the backlight unit into a plurality of horizontal regions, and performs, in each of the plurality of horizontal regions, a vertical direction scan operation that sequentially selects the plurality of light source rows and a horizontal direction sequential driving operation that sequentially drives the plurality of light source blocks included in a selected one of the plurality of light source rows.

In example embodiments, to perform the horizontal direction sequential driving operation in each of the plurality of horizontal regions, the backlight driver may sequentially drive one of the plurality of light source blocks included in the selected one of the plurality of light source rows in each of the plurality of horizontal regions per a block shift time.

In example embodiments, the block shift time may be determined by dividing a latency time from a data input time point to an image display time point by a number of the plurality of light source blocks included in each of the plurality of light source rows in each of the plurality of horizontal regions.

In example embodiments, to perform the horizontal direction sequential driving operation in each of the plurality of horizontal regions, the backlight driver may sequentially drive the plurality of light source blocks in the selected one of the plurality of light source rows in each of the plurality of horizontal regions in a first horizontal direction in an odd-numbered frame, and may sequentially drive the plurality of light source blocks in the selected one of the plurality of light source rows in each of the plurality of horizontal regions in a second horizontal direction opposite to the first horizontal direction in an even-numbered frame.

In example embodiments, the backlight driver may group the plurality of light source rows into an odd-numbered light source row group and an even-numbered light source row group. To perform the horizontal direction sequential driving operation in each of the plurality of horizontal regions, the backlight driver may sequentially drive the plurality of light source blocks in the selected one of the plurality of light source rows belonging to the odd-numbered light source row group in each of the plurality of horizontal regions in a first horizontal direction, and may sequentially drive the plurality of light source blocks in the selected one of the plurality of light source rows belonging to the even-numbered light source row group in each of the plurality of horizontal regions in a second horizontal direction opposite to the first horizontal direction.

In example embodiments, the backlight driver may group the plurality of light source rows into an odd-numbered light source row group and an even-numbered light source row group. To perform the horizontal direction sequential driving operation in each of the plurality of horizontal regions in an odd-numbered frame, the backlight driver may sequentially drive the plurality of light source blocks in the selected one of the plurality of light source rows belonging to the odd-numbered light source row group in each of the plurality of horizontal regions in a first horizontal direction, and may sequentially drive the plurality of light source blocks in the selected one of the plurality of light source rows belonging to the even-numbered light source row group in each of the plurality of horizontal regions in a second horizontal direction opposite to the first horizontal direction. To perform the horizontal direction sequential driving operation in each of the plurality of horizontal regions in an even-numbered frame, the backlight driver may sequentially drive the plurality of light source blocks in the selected one of the plurality of light source rows belonging to the odd-numbered light source row group in each of the plurality of horizontal regions in the second horizontal direction, and may sequentially drive the plurality of light source blocks in the selected one of the plurality of light source rows belonging to the even-numbered light source row group in each of the plurality of horizontal regions in the first horizontal direction.

In example embodiments, the backlight driver may group (4K+1)-th and (4K+2)-th ones of the plurality of light source rows into a first light source row group, and may group (4K+3)-th and (4K+4)-th ones of the plurality of light source rows into a second light source row group, where K is an integer greater than 0. To perform the horizontal direction sequential driving operation in each of the plurality of horizontal regions, the backlight driver may sequentially drive the plurality of light source blocks in the selected one of the plurality of light source rows belonging to the first light source row group in each of the plurality of horizontal regions in a first horizontal direction, and may sequentially drive the plurality of light source blocks in the selected one of the plurality of light source rows belonging to the second light source row group in each of the plurality of horizontal regions in a second horizontal direction opposite to the first horizontal direction.

In example embodiments, the backlight driver may group (4K+1)-th and (4K+2)-th ones of the plurality of light source rows into a first light source row group, and may group (4K+3)-th and (4K+4)-th ones of the plurality of light source rows into a second light source row group, where K is an integer greater than 0. To perform the horizontal direction sequential driving operation in each of the plurality of horizontal regions in an odd-numbered frame, the backlight driver may sequentially drive the plurality of light source blocks in the selected one of the plurality of light source rows belonging to the first light source row group in each of the plurality of horizontal regions in a first horizontal direction, and may sequentially drive the plurality of light source blocks in the selected one of the plurality of light source rows belonging to the second light source row group in each of the plurality of horizontal regions in a second horizontal direction opposite to the first horizontal direction. To perform the horizontal direction sequential driving operation in each of the plurality of horizontal regions in an even-numbered frame, the backlight driver may sequentially drive the plurality of light source blocks in the selected one of the plurality of light source rows belonging to the first light source row group in each of the plurality of horizontal regions in the second horizontal direction, and may sequentially drive the plurality of light source blocks in the selected one of the plurality of light source rows belonging to the second light source row group in each of the plurality of horizontal regions in the first horizontal direction.

In example embodiments, to perform the horizontal direction sequential driving operation in an odd-numbered horizontal region of the plurality of horizontal regions, the backlight driver may sequentially drive the plurality of light source blocks in the selected one of the plurality of light source rows in the odd-numbered horizontal region in a first horizontal direction. To perform the horizontal direction sequential driving operation in an even-numbered horizontal region of the plurality of horizontal regions, the backlight driver may sequentially drive the plurality of light source blocks in the selected one of the plurality of light source rows in the even-numbered horizontal region in a second horizontal direction opposite to the first horizontal direction.

In example embodiments, the horizontal direction sequential driving operation in the odd-numbered horizontal region and the horizontal direction sequential driving operation in the even-numbered horizontal region may have different start time points.

In example embodiments, the horizontal direction sequential driving operation in the odd-numbered horizontal region and the horizontal direction sequential driving operation in the even-numbered horizontal region may have different block shift times.

In example embodiments, to perform the horizontal direction sequential driving operation in an odd-numbered horizontal region of the plurality of horizontal regions, the backlight driver may sequentially drive the plurality of light source blocks in the selected one of the plurality of light source rows in the odd-numbered horizontal region in a first horizontal direction in an odd-numbered frame, and may sequentially drive the plurality of light source blocks in the selected one of the plurality of light source rows in the odd-numbered horizontal region in a second horizontal direction opposite to the first horizontal direction in an even-numbered frame. To perform the horizontal direction sequential driving operation in an even-numbered horizontal region of the plurality of horizontal regions, the backlight driver may sequentially drive the plurality of light source blocks in the selected one of the plurality of light source rows in the even-numbered horizontal region in the second horizontal direction in the odd-numbered frame, and may sequentially drive the plurality of light source blocks in the selected one of the plurality of light source rows in the even-numbered horizontal region in the first horizontal direction in the even-numbered frame.

In example embodiments, the horizontal direction sequential driving operation in the odd-numbered horizontal region and the horizontal direction sequential driving operation in the even-numbered horizontal region may have different start time points or different block shift times.

An embodiment may be related to a display device. The display device includes a backlight unit including light source rows, each of the light source rows including light source blocks; a display panel configured to display an image by transmitting light emitted by the backlight unit; a panel driver configured to drive the display panel; and a backlight driver configured to drive the backlight unit. The backlight driver is configured to perform a vertical direction scan operation that sequentially selects the light source rows and a horizontal direction sequential driving operation that sequentially drives the light source blocks included in a selected light source row of the light source rows.

To perform the vertical direction scan operation, the backlight driver is configured to sequentially select a light source row of the light source rows based on a first time period.

The first time period is determined by dividing a frame time by a number of the light source rows.

To perform the horizontal direction sequential driving operation, the backlight driver is configured to sequentially drive a light source block of the light source blocks included in the selected light source row of the light source rows based on a second time period.

The second time period is determined by dividing a latency time from a data input time point to an image display time point by a number of the light source blocks included in each of the light source rows.

The light source rows include a first light source row and a second light source row, and the backlight driver is configured to initiate the horizontal direction sequential driving operation for the second light source row before the horizontal direction sequential driving operation for the first light source row is completed.

Each of the light source rows includes first through M-th light source blocks, where M is an integer greater than 1. To perform the horizontal direction sequential driving operation, the backlight driver is configured to sequentially drive the first through M-th light source blocks included in the selected light source row of the light source rows in a first horizontal direction from the first light source block to the M-th light source block in an odd-numbered frame, and sequentially drive the first through M-th light source blocks included in the selected light source row of the light source rows in a second horizontal direction from the M-th light source block to the first light source block in an even-numbered frame.

In an embodiment, the display device includes a backlight unit including light source rows, each of the light source rows including light source blocks; a display panel configured to display an image by transmitting light emitted by the backlight unit; a panel driver configured to drive the display panel; and a backlight driver configured to drive the backlight unit. The backlight driver is configured to divide the backlight unit into horizontal regions, and perform, in each of the horizontal regions, a vertical direction scan operation that sequentially selects the light source rows and a horizontal direction sequential driving operation that sequentially drives the light source blocks included in a selected light source row of the light source rows.

To perform the horizontal direction sequential driving operation in each of the horizontal regions, the backlight driver is configured to sequentially drive a light source block of the light source blocks included in the selected light source row of the light source rows in each of the horizontal regions per a block shift time.

The block shift time is determined by dividing a latency time from a data input time point to an image display time point by a number of the light source blocks included in each of the light source rows in each of the horizontal regions.

To perform the horizontal direction sequential driving operation in each of the horizontal regions, the backlight driver is configured to sequentially drive the light source blocks in the selected light source row of the light source rows in each of the horizontal regions in a first horizontal direction in an odd-numbered frame, and sequentially drive the light source blocks in the selected light source row of the light source rows in each of the horizontal regions in a second horizontal direction opposite to the first horizontal direction in an even-numbered frame.

The backlight driver is configured to group the light source rows into an odd-numbered light source row group and an even-numbered light source row group. To perform the horizontal direction sequential driving operation in each of the horizontal regions, the backlight driver is configured to sequentially drive the light source blocks in the selected light source row of the light source rows belonging to the odd-numbered light source row group in each of the horizontal regions in a first horizontal direction, and sequentially drive the light source blocks in the selected light source row of the light source rows belonging to the even-numbered light source row group in each of the horizontal regions in a second horizontal direction opposite to the first horizontal direction.

The backlight driver is configured to group the light source rows into an odd-numbered light source row group and an even-numbered light source row group. To perform the horizontal direction sequential driving operation in each of the horizontal regions in an odd-numbered frame, the backlight driver is configured to sequentially drive the light source blocks in the selected light source row of the light source rows belonging to the odd-numbered light source row group in each of the horizontal regions in a first horizontal direction, and sequentially drive the light source blocks in the selected light source row of the light source rows belonging to the even-numbered light source row group in each of the horizontal regions in a second horizontal direction opposite to the first horizontal direction. To perform the horizontal direction sequential driving operation in each of the horizontal regions in an even-numbered frame, the backlight driver is configured to sequentially drive the light source blocks in the selected light source row of the light source rows belonging to the odd-numbered light source row group in each of the horizontal regions in the second horizontal direction, and sequentially drive the light source blocks in the selected light source row of the light source rows belonging to the even-numbered light source row group in each of the horizontal regions in the first horizontal direction.

The backlight driver is configured to group (4K+1)-th and (4K+2)-th light source rows of the light source rows into a first light source row group, and group (4K+3)-th and (4K+4)-th light source rows of the light source rows into a second light source row group, where K is an integer greater than 0. To perform the horizontal direction sequential driving operation in each of the horizontal regions, the backlight driver is configured to sequentially drive the light source blocks in the selected light source row of the light source rows belonging to the first light source row group in each of the horizontal regions in a first horizontal direction, and sequentially drive the light source blocks in the selected light source row of the light source rows belonging to the second light source row group in each of the horizontal regions in a second horizontal direction opposite to the first horizontal direction.

The backlight driver is configured to group (4K+1)-th and (4K+2)-th light source rows of the light source rows into a first light source row group, and group (4K+3)-th and (4K+4)-th light source rows of the light source rows into a second light source row group, where K is an integer greater than 0. To perform the horizontal direction sequential driving operation in each of the horizontal regions in an odd-numbered frame, the backlight driver is configured to sequentially drive the light source blocks in the selected light source row of the light source rows belonging to the first light source row group in each of the horizontal regions in a first horizontal direction, and sequentially drive the light source blocks in the selected light source row of the light source rows belonging to the second light source row group in each of the horizontal regions in a second horizontal direction opposite to the first horizontal direction. To perform the horizontal direction sequential driving operation in each of the horizontal regions in an even-numbered frame, the backlight driver is configured to sequentially drive the light source blocks in the selected light source row of the light source rows belonging to the first light source row group in each of the horizontal regions in the second horizontal direction, and sequentially drive the light source blocks in the selected light source row of the light source rows belonging to the second light source row group in each of the horizontal regions in the first horizontal direction.

To perform the horizontal direction sequential driving operation in an odd-numbered horizontal region of the horizontal regions, the backlight driver is configured to sequentially drive the light source blocks in the selected light source row of the light source rows in the odd-numbered horizontal region in a first horizontal direction. To perform the horizontal direction sequential driving operation in an even-numbered horizontal region of the horizontal regions, the backlight driver is configured to sequentially drive the light source blocks in the selected light source row of the light source rows in the even-numbered horizontal region in a second horizontal direction opposite to the first horizontal direction.

The horizontal direction sequential driving operation in the odd-numbered horizontal region and the horizontal direction sequential driving operation in the even-numbered horizontal region have different start time points.

The horizontal direction sequential driving operation in the odd-numbered horizontal region and the horizontal direction sequential driving operation in the even-numbered horizontal region have different block shift times.

To perform the horizontal direction sequential driving operation in an odd-numbered horizontal region of the horizontal regions, the backlight driver is configured to sequentially drive the light source blocks in the selected light source row of the light source rows in the odd-numbered horizontal region in a first horizontal direction in an odd-numbered frame, and sequentially drive the light source blocks in the selected light source row of the light source rows in the odd-numbered horizontal region in a second horizontal direction opposite to the first horizontal direction in an even-numbered frame. To perform the horizontal direction sequential driving operation in an even-numbered horizontal region of the horizontal regions, the backlight driver is configured to sequentially drive the light source blocks in the selected light source row of the light source rows in the even-numbered horizontal region in the second horizontal direction in the odd-numbered frame, and sequentially drive the light source blocks in the selected light source row of the light source rows in the even-numbered horizontal region in the first horizontal direction in the even-numbered frame.

The horizontal direction sequential driving operation in the odd-numbered horizontal region and the horizontal direction sequential driving operation in the even-numbered horizontal region have different start time points or different block shift times.

As described above, a display device according to example embodiments may perform a vertical direction scan operation that sequentially selects light source rows included in a backlight unit, and a horizontal direction sequential driving operation that sequentially drives light source blocks included in a selected one of the light source rows. Accordingly, while local dimming is performed, a waterfall phenomenon where a relatively high or low luminance horizontal line image exists or gradually moves may be prevented or reduced.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, embodiments of the present inventive concept will be explained in detail with reference to the accompanying drawings.

FIG. 1is a block diagram illustrating a display device100according to an example embodiment.FIG. 2is a diagram of a backlight unit160included in a display device according to an example embodiment.

Referring toFIG. 1, the display device100may include a display panel110, a panel driver120that drives the display panel110, the backlight unit160, and a backlight driver170that drives the backlight unit160. In an example embodiment, the panel driver120may include a data driver130that provides data signals DS to the display panel110, a gate driver140that provides gate signals GS to the display panel110, and a controller150that controls an operation of the display device100.

The display panel110may include data lines, gate lines, and pixels PX coupled to the data lines and the gate lines. The display panel110may selectively transmit light emitted by the backlight unit160to display an image. In some example embodiments, each pixel PX may include a switching transistor and a liquid crystal capacitor coupled to the switching transistor, and the display panel110may be a liquid crystal display (LCD) panel. However, the display panel110according to example embodiments may be any suitable display panel. The display panel110may include pixel blocks respectively corresponding to light source blocks of the backlight unit160. Here, a set of the pixels PX located corresponding to one light source block may be referred to as the pixel block. Thus, here, the pixel block may be a logical unit of the pixels PX that are grouped according to the light source block, and the pixel blocks may not be physically or structurally distinguished from each other.

The data driver130may generate the data signals DS based on output image data ODAT and a data control signal DCTRL received from the controller150, and may provide the data signals DS to the pixels PX through the data lines. For example, the data control signal DCTRL may include an output data enable signal, a horizontal start signal and a load signal. In an example embodiment, the data driver130may be implemented with one or more data integrated circuits (ICs). Further, according to an example embodiment, the data driver130may be mounted directly on the display panel110in a form of a chip on glass (COG), or may be coupled to the display panel110in a form of a chip on film (COF) or a tape carrier package (TCP). In an example embodiment, the data driver130may be integrated in a peripheral portion of the display panel110.

The gate driver140may generate the gate signals GS based on a gate control signal GCTRL received from the controller150, and may provide the gate signals GS to the pixels PX through the gate lines. For example, the gate control signal GCTRL may include a vertical start signal STV and a gate clock signal. In some example embodiments, the gate driver140may be implemented as an amorphous silicon gate (ASG) driver integrated in the peripheral portion of the display panel110. In other example embodiments, the gate driver140may be implemented with one or more gate ICs. Further, according to some example embodiments, the gate driver140may be mounted directly on the display panel110in the form of COG, or may be coupled to the display panel110in the form of COF or TCP.

The controller150, e.g., a timing controller, may receive input image data IDAT and a control signal CTRL from an external host, e.g., a graphic processing unit (GPU) or a graphic card. For example, the input image data IDAT may be RGB image data including red image data, green image data and blue image data. Further, for example, the control signal CTRL may include a master clock signal, a data enable signal, a vertical synchronization signal, a horizontal synchronization signal, etc. The controller150may generate the output image data ODAT, the data control signal DCTRL, the gate control signal GCTRL and a backlight control signal BCTRL based on the input image data IDAT and the control signal CTRL. In some example embodiments, the controller150may generate the output image data ODAT by performing an image enhancement operation, a luminance non-uniformity correction operation, a dynamic capacitance compensation (DCC) operation, etc. on the input image data IDAT. The controller150may control an operation of the data driver130by providing the output image data ODAT and the data control signal DCTRL to the data driver130, may control an operation of the gate driver140by providing the gate control signal GCTRL to the gate driver140, and may control an operation of the backlight driver170by providing the backlight control signal BCTRL to the backlight driver170.

The backlight driver170may drive the backlight unit160based on the backlight control signal BCTRL received from the controller150. In an example embodiment, the backlight control signal BCTRL may include a dimming signal SDIM representing that local dimming is to be performed, and the backlight driver170may perform the local dimming in response to the dimming signal SDIM. In some example embodiments, the dimming signal SDIM may further represent duties of light source block driving signals, e.g., pulse width modulation (PWM) signals, that are to be respectively applied to the N*M light source blocks B11, B12, . . . , B1M, B21, B22, . . . , B2M, . . . , BN1, BN2, . . . , BNM included in the backlight unit160. For example, the controller150may determine the duties of the light source block driving signals by analyzing the input image data IDAT for the pixel blocks of the display panel110respectively corresponding to the N*M light source blocks B11, B12, . . . , B1M, B21, B22, . . . , B2M, . . . , BN1, BN2, . . . , BNM, and may provide the dimming signal SDIM representing the determined duties to the backlight driver170. In an example, the controller150may determine the duty of the light source block driving signal for each light source block according to a representative gray value (e.g., a maximum gray value and/or an average gray value) of the pixel block corresponding to each light source block. The backlight driver170may perform the local dimming by driving the N*M light source blocks B11, B12, . . . , B1M, B21, B22, . . . , B2M, . . . , BN1, BN2, . . . , BNM with the determined duties represented by the dimming signal SDIM, or by driving the N*M light source blocks B11, B12, . . . , B1M, B21, B22, . . . , B2M, . . . , BN1, BN2, . . . , BNM for durations corresponding to the determined duties.

In a conventional display device, light source rows of a backlight unit may be sequentially driven to perform the local dimming, and light source blocks in each light source row may be substantially simultaneously driven. Since the light source blocks in each light source row are substantially simultaneously driven, luminance of each light source block may be affected by luminances of adjacent light source blocks. In particular, when the local dimming is performed in the conventional display device, a waterfall phenomenon where a relatively high or low luminance horizontal line image exists or gradually moves may be caused by the sequential driving of the light source rows. However, in the display device100according to an example embodiment, the light source blocks B11, B12, . . . , B1M, B21, B22, . . . , B2M, . . . , BN1, BN2, . . . , BNM of the backlight unit160are sequentially driven in the vertical direction and the horizontal direction by the vertical direction scan operation and the horizontal direction sequential driving operation. Accordingly, the influence of the luminance of the adjacent light source blocks on the luminance of each light source block may be reduced, and the waterfall phenomenon may be prevented or reduced while the local dimming is performed.

FIG. 3is a flowchart of an operation of a display device according to an example embodiment.FIG. 4is a diagram illustrating driving timing of a backlight unit of a display device performing only a vertical direction scan operation and a driving timing of a backlight unit of a display device performing both of a vertical direction scan operation and a horizontal direction sequential driving operation according to an example embodiment.FIG. 5is a diagram of an operation of a backlight unit of a display device performing only a vertical direction scan operation and an operation of a backlight unit of a display device performing both of a vertical direction scan operation and a horizontal direction sequential driving operation according to driving timings ofFIG. 4according to an example embodiment.FIG. 6is a diagram of an operation of a backlight unit of a display device performing only a vertical direction scan operation and an operation of a backlight unit of a display device performing both of a vertical direction scan operation and a horizontal direction sequential driving operation according to an example embodiment.FIG. 7is a diagram of a driving timing of a backlight unit of a display device performing only a vertical direction scan operation and a driving timing of a backlight unit of a display device performing both of a vertical direction scan operation and a horizontal direction sequential driving operation according to an example embodiment.FIG. 8is a diagram of luminance influences by adjacent light source blocks of first light source rows according to driving timings ofFIG. 7according to an example embodiment.FIG. 9is a diagram of a driving timing of a backlight unit of a display device performing only a vertical direction scan operation and a driving timing of a backlight unit of a display device performing both of a vertical direction scan operation and a horizontal direction sequential driving operation according to an example embodiment.FIG. 10is a diagram of luminance influences by adjacent light source blocks of first light source rows according to driving timings ofFIG. 9according to an example embodiment.FIG. 11is a diagram of an image displayed by a display device performing only a vertical direction scan operation and of an image displayed by a display device performing both of a vertical direction scan operation and a horizontal direction sequential driving operation according to an example embodiment.

Referring toFIGS. 1 and 3, the panel driver120of the display device100may receive input image data IDAT in an operation S210, and may drive the display panel110based on the input image data IDAT in an operation S230. For example, the controller150may provide the data driver130with output image data ODAT corresponding to the input image data IDAT, the data driver130may provide the display panel110with data signals DS corresponding to the output image data ODAT, and the gate driver140may provide the display panel110with gate signals GS. Transmittance, or transmission factors, of the pixels PX of the display panel110may be adjusted based on the data signals DS and the gate signals GS. Further, the controller150may provide the backlight driver170with a dimming signal SDIM representing that local dimming is to be performed.

The backlight driver170may perform a vertical direction scan operation and a horizontal direction sequential driving operation for the backlight unit160in response to the dimming signal SDIM in an operation S250. The vertical direction scan operation may be an operation that sequentially selects light source rows included in the backlight unit160in a vertical direction, e.g., a direction of each data line, and the horizontal direction sequential driving operation may be an operation that sequentially drives light source blocks included in each light source row in a horizontal direction, e.g., a direction of each gate line.

For example, as illustrated in driving timing310ofFIG. 4, a display device that performs only a vertical direction scan operation V-SCAN may sequentially drive the light source rows LSR1, LSR2, LSR3, . . . , and light source blocks included in each light source row, e.g., the light source row LSR1, may be substantially simultaneously driven. However, as illustrated in driving timing320ofFIG. 4, the display device100according to example embodiments may perform the vertical direction scan operation V-SCAN that sequentially selects the light source rows LSR1, LSR2, LSR3, . . . , and a horizontal direction sequential driving operation H-SD that sequentially drives the light source blocks, e.g., B11, B12, B13, . . . , B1M, included in each selected light source row, e.g., light source row LSR1.

To perform the vertical direction scan operation V-SCAN, the backlight driver170may sequentially select one of the light source rows LSR1, LSR2, LSR3, . . . per first time T1, e.g., based on a first time period. The first time T1is a first time period, or a length of time, from a time point. A time point is a specific point in time, e.g., a specific point in time when a light source row is selected. For example, the backlight driver170may select the second light source row LSR2after the first time T1from a time point at which a first light source row LSR1is selected, and may select the third light source row LSR3after the first time T1from a time point at which the second light source row LSR2is selected. In some example embodiments, the first time T1may be determined by dividing a frame time FT by the number of the light source rows LSR1, LSR2, LSR3, . . . . The frame time FT is a time period, or length of time, of a frame. For example, in a case where the display device100operates at a frame rate of about 120 Hz, and the backlight unit160includes 16 light source rows LSR1, LSR2, LSR3, . . . , the frame time FT may be about 8.3 ms (= 1/120 ms), and the first time T1may be about 0.52 ms (=8.3/16 ms).

Further, to perform the horizontal direction sequential driving operation H-SD, the backlight driver170may sequentially drive one of the light source blocks, e.g., light source blocks B11, B12, B13, . . . , B1M, included in the selected light source row, e.g., light source row LSR1, per second time T2. The second time T2is a second time period, or a length of time, from a time point. For example, when the first light source row LSR1is selected, the light source blocks B11, B12, B13, . . . , B1M of the first light source row LSR1may be sequentially driven per the second time T2. Further, when the second light source row LSR2is selected after the first time T1from the time point at which the first light source row LSR1is selected, the light source blocks B21, B22, B23, . . . , B2M of the second light source row LSR2may be sequentially driven per the second time T2. In some example embodiments, as illustrated inFIG. 4, before the horizontal direction sequential driving operation H-SD for the first light source row LSR1is completed, the second light source row LSR2may be selected by the vertical direction scan operation V-SCAN, and the horizontal direction sequential driving operation H-SD for the selected second light source row LSR2may be initiated. Further, when the third light source row LSR3is selected after the first time T1from the time point at which the second light source row LSR2is selected, the light source blocks B31, B32, B33, . . . , B3M of the third light source row LSR3may be sequentially driven per the second time T2. In some example embodiments, the second time T2may be determined based on a latency time LT, i.e., a time period, from a data input time point at which the input image data IDAT are input, or a time point at which a vertical start signal STV is generated, to an image display time point at which an image corresponding to the input image data IDAT is displayed. The latency time LT may be previously determined by a standard or a specification of the display device100. For example, the second time T2may be determined by dividing the latency time LT by the number of the light source blocks, e.g., light source blocks B11, B12, B13, . . . , B1M, included in each light source row, e.g., light source row LSR1. In an example, in a case where the latency time LT is about 2 ms, and each light source row includes 40 light source blocks, the second time T2may be about 50 μs (=2000/40 μs). In this case, driving the second light source block B12of the first light source row LSR1may be initiated after the second time T2of about 50 μs from a time point at which driving the first light source block B11of the first light source row LSR1is initiated. Further, driving the third light source block B13of the first light source row LSR1may be initiated after the second time T2of about 50 μs from a time point at which driving the second light source block B12of the first light source row LSR1is initiated. The second time T2that is an interval of driving start time points of the light source blocks in each light source row may be referred to as a block shift time or a phase shift time.

In the display device that performs only the vertical direction scan operation V-SCAN and the display device100that performs the vertical direction scan operation V-SCAN and the horizontal direction sequential driving operation H-SD, the backlight unit160may operate as illustrated inFIG. 5by driving timings310and320ofFIG. 4. That is, in the display device that operates according to the driving timing310, the first light source row LSR1may emit light, and, after the first time T1, the second light source row LSR2may emit light. Then, after the first time T1, the third light source row LSR3may emit light.

However, in the display device100that operates according to the driving timing320, light emission of a first light source block B11of the first light source row LSR1may be initiated. Light emission of a second light source block B12of the first light source row LSR1may be initiated after the second time T2. Light emission of a third light source block B13of the first light source row LSR1may be initiated after the second time T2. Light emission of a fourth light source block B14of the first light source row LSR1may be initiated after the second time T2.

Then, light emission of a first light source block B21of the second light source row LSR2and a fifth light source block B15of the first light source row LSR1may be initiated. Light emission of a second light source block B22of the second light source row LSR2and a sixth light source block B16of the first light source row LSR1may be initiated after the second time T2. Light emission of a third light source block B23of the second light source row LSR2and a seventh light source block B17of the first light source row LSR1may be initiated after the second time T2. Light emission of a fourth light source block B24of the second light source row LSR2and an eighth light source block B18of the first light source row LSR1may be initiated after the second time T2.

Then, light emission of a first light source block B31of the third light source row LSR3, a fifth light source block B25of the second light source row LSR2and a ninth light source block B19of the first light source row LSR1may be initiated. Light emission of a second light source block B32of the third light source row LSR3and a sixth light source block B26of the second light source row LSR2may be initiated after the second time T2. Light emission of a third light source block B33of the third light source row LSR3and a seventh light source block B27of the second light source row LSR2may be initiated after the second time T2. Light emission of a fourth light source block B34of the third light source row LSR3and an eighth light source block B28of the second light source row LSR2may be initiated after the second time T2.

An operation of the display device that performs only the vertical direction scan operation V-SCAN and the display device100that performs the vertical direction scan operation V-SCAN and the horizontal direction sequential driving operation H-SD may be expressed as graphs315and325inFIG. 6. That is, in the display device that performs only the vertical direction scan operation V-SCAN, as illustrated as the graph315inFIG. 6, the light source blocks B1through B9of the first light source row LSR1may substantially simultaneously emit light, and, after the first time T1, the light source blocks B1through B9of the second light source row LSR2may substantially simultaneously emit light.

However, in the display device100that performs the vertical direction scan operation V-SCAN and the horizontal direction sequential driving operation H-SD, as illustrated as the graph325inFIG. 6, the light source rows LSR1, LSR2, . . . may be sequentially selected per the first time T1, and the light source blocks B1through B9of each of the sequentially selected light source rows LSR1, LSR2, . . . may be sequentially driven per the second time T2.

Luminance influence of adjacent light source blocks on each light source block in the display device100may be reduced compared with the luminance influence of the adjacent light source blocks on each light source block in the display device that performs only the vertical direction scan operation V-SCAN. For example,FIG. 8illustrates the luminance influence of the adjacent light source blocks on each light source block of the first light source row LSR1in display devices that operate according to driving timings330and340illustrated inFIG. 7. FIG.10illustrates the luminance influence of the adjacent light source blocks on each light source block of the first light source row LSR1in display devices that operate according to driving timings350and360illustrated inFIG. 9. InFIGS. 8 and 10, each of light source blocks B11through B19of the first light source row LSR1may be equally divided into four regions along the vertical direction, and the luminance influence of the adjacent light source blocks at the equally divided four regions of each light source block B11through B19may be expressed as numerical values. Further, the values of the luminance influence of the adjacent light source blocks illustrated inFIGS. 8 and 10may be relative values, and may not have a particular unit, or measure. For example, the values of the luminance influence of the adjacent light source blocks illustrated inFIGS. 8 and 10may be determined by assuming luminance of one light source block emitting light as 1.

For example, as illustrated in the driving timing330ofFIG. 7, in a case where the light source rows LSR1, LSR2, LSR3, . . . sequentially emit light, and a light emission time of each light source row, e.g., light source row LSR1, corresponding to a half of the first time T1, as illustrated in diagram335ofFIG. 8, lower half regions of the light source blocks B11through B19of the first light source row LSR1may be affected by the luminance influence ranging from about 1.75 to about 2.5. However, as illustrated in the driving timing340ofFIG. 7, in a case where the light source rows LSR1, LSR2, LSR3, . . . are sequentially selected, and the light source blocks B11through B19of each selected light source row, e.g., light source row LSR1, are sequentially driven, as illustrated in diagram345ofFIG. 8, lower half regions of the light source blocks B11through B19of the first light source row LSR1may be affected by the luminance influence ranging from about 0 to about 1.5. Accordingly, compared with the display device that performs only the vertical direction scan operation V-SCAN, the luminance influence of the adjacent light source blocks on each light source block in the display device100may be reduced.

Further, for example, as illustrated in the driving timing350ofFIG. 9, in a case where the light source rows LSR1, LSR2, LSR3, . . . sequentially emit light, and a light emission time of each light source row, e.g., light source row LSR1, corresponding to a double of the first time T1, as illustrated in diagram355ofFIG. 10, the divided regions of the light source blocks B11through B19of the first light source row LSR1may be affected by the luminance influence ranging from about 1.75 to about 3.85. However, as illustrated in the driving timing360ofFIG. 9, in a case where the light source rows LSR1, LSR2, LSR3, . . . are sequentially selected, and the light source blocks B11through B19of each selected light source row, e.g., light source row LSR1, are sequentially driven, as illustrated in diagram365ofFIG. 10, the divided regions of the light source blocks B11through B19of the first light source row LSR1may be affected by the luminance influence ranging from about 0 to about 3.05. Accordingly, compared with the display device that performs only the vertical direction scan operation V-SCAN, the luminance influence of the adjacent light source blocks on each light source block in the display device100according to example embodiments may be reduced.

As illustrated inFIG. 11, in an image410displayed at the display device that performs only the vertical direction scan operation V-SCAN, a waterfall phenomenon where a relatively high or low luminance horizontal line image exists or gradually moves may occur. However, by the reduction of the luminance influence of the adjacent light source blocks, in an image430displayed at the display device100that performs the vertical direction scan operation V-SCAN and the horizontal direction sequential driving operation H-SD, the waterfall phenomenon may be prevented or reduced.

FIG. 12is a flowchart of an operation of a display device according to an example embodiment.FIG. 13is a diagram of an operation of a backlight unit of a display device performing only a vertical direction scan operation and of an operation of a backlight unit of a display device performing an operation ofFIG. 12according to an example embodiment.FIG. 14is a diagram of an image displayed by a display device performing only a vertical direction scan operation and an image displayed by a display device performing an operation ofFIG. 12according to an example embodiment.

Referring toFIGS. 1 and 12, the panel driver120of the display device100may receive input image data IDAT in an operation S510, and may drive the display panel110based on the input image data IDAT in an operation S530.

The backlight driver170may perform, in an odd-numbered frame, a vertical direction scan operation, and a horizontal direction sequential driving operation in a first horizontal direction in an operation S550: ODD FRAME, and in an operation S580, and may perform, in an even-numbered frame, the vertical direction scan operation, and the horizontal direction sequential driving operation in a second horizontal direction opposite to the first horizontal direction in operation S550: EVEN FRAME, and in an operation S590. In some example embodiments, each light source row of a backlight unit160may include first through M-th light source blocks, the horizontal direction sequential driving operation in the first horizontal direction may be an operation that sequentially drives the first through M-th light source blocks in an order from the first light source block to the M-th light source block, and the horizontal direction sequential driving operation in the second horizontal direction may be an operation that sequentially drives the first through M-th light source blocks in an order from the M-th light source block to the first light source block.

For example, as illustrated as a graph610inFIG. 13, in a display device that performs only the vertical direction scan operation V-SCAN, the light source rows LSR1, LSR2, . . . may sequentially emit light, and the light emission operation in the odd-numbered frame may be the same as the light emission operation in the even-numbered frame. However, in the display device100that performs the operation ofFIG. 12, the light source blocks B11through B19of each light source row LSR1may sequentially emit light in the first horizontal direction from the leftmost light source block B11in the odd-numbered frame. The vertical direction scan operation V-SCAN and the horizontal direction sequential driving operation H-SD in the first horizontal direction in the odd-numbered frame may be expressed as a graph630inFIG. 13. Further, in the display device100that performs the operation ofFIG. 12, the light source blocks B11through B19of each light source row LSR1may sequentially emit light in the second horizontal direction from the rightmost light source block B19in the even-numbered frame. The vertical direction scan operation V-SCAN and the horizontal direction sequential driving operation H-SD in the second horizontal direction in the even-numbered frame may be expressed as a graph650inFIG. 13. That is, in the display device100that performs the operation ofFIG. 12, the directions of the horizontal direction sequential driving operation H-SD may be inverted in the odd-numbered frame and the even-numbered frame, and this operation may be referred to as a frame inversion operation.

As illustrated inFIG. 14, in an image710displayed at the display device that performs only the vertical direction scan operation V-SCAN, a waterfall phenomenon where a relatively high or low luminance horizontal line image exists or gradually moves may occur. However, in an image730displayed at the display device100that performs the vertical direction scan operation V-SCAN, the horizontal direction sequential driving operation H-SD and the frame inversion operation, the waterfall phenomenon may be prevented or reduced.

FIG. 15is a flowchart of an operation of a display device according to an example embodiment.FIG. 16is a diagram of an operation of a backlight unit of a display device performing an operation ofFIG. 15according to an example embodiment.

Referring toFIGS. 1 and 15, the panel driver120of the display device100may receive input image data IDAT in an operation S810, and may drive a display panel110based on the input image data IDAT in an operation S830.

The backlight driver170may divide the backlight unit160into horizontal regions in an operation S850, and may perform, in each horizontal region, a vertical direction scan operation that sequentially selects the light source rows of the backlight unit160and a horizontal direction sequential driving operation that sequentially drives the light source blocks included in the selected light source row in an operation S870. Here, each horizontal region may include two or more consecutive light source columns of the backlight unit160.

For example, as illustrated as a graph900inFIG. 16, the backlight driver170may divide the backlight unit160into a first horizontal region HR1including first through third light source blocks B1, B2and B3of each light source row, a second horizontal region HR2including fourth through sixth light source blocks B4, B5and B6of each light source row, and a third horizontal region HR3including seventh through ninth light source blocks B7, B8and B9of each light source row. With respect to the first horizontal region HR1, the backlight driver170may perform the vertical direction scan operation that sequentially select the light source rows, and the horizontal direction sequential driving operation that sequentially drives the first through third light source blocks B1, B2and B3included in each of portions LSR11, LSR21, . . . of the sequentially selected light source rows in the first horizontal region HR1. With respect to the second horizontal region HR2, the backlight driver170may perform the vertical direction scan operation that sequentially select the light source rows, and the horizontal direction sequential driving operation that sequentially drives the fourth through sixth light source blocks B4, B5and B6included in each of portions LSR12, LSR22, . . . of the sequentially selected light source rows in the second horizontal region HR2. With respect to the third horizontal region HR3, the backlight driver170may perform the vertical direction scan operation that sequentially select the light source rows, and the horizontal direction sequential driving operation that sequentially drives the seventh through ninth light source blocks B7, B8and B9included in each of portions LSR13, LSR23, . . . of the sequentially selected light source rows in the third horizontal region HR3.

FIG. 16illustrates an example where each light source row includes nine light source blocks B1through B9, and each horizontal region HR1, HR2and HR3includes three light source columns, the number of light source blocks B1through B9in each light source row may be different, the number of the horizontal regions HR1, HR2and HR3may be different, and the number of the light source columns in each horizontal region HR1, HR2and HR3may be different.

As described above with reference toFIGS. 3 through 11, in the display device100that performs an operation illustrated inFIG. 3, a second time T2, i.e., a block shift time or a phase shift time, that is an interval of driving start time points of the light source blocks in each light source row may be determined by dividing a latency time LT by the number of the light source blocks in each light source row. Thus, as the number of the light source blocks in each light source row increases, the block shift time may be decreased. If the block shift time is decreased, luminance influence of an adjacent light source block on each light source block may be increased.

However, in the display device100that performs an operation illustrated inFIG. 15, the backlight unit160may be divided into the horizontal regions HR1, HR2and HR3, and, in each horizontal region, e.g., horizontal region HR1, the horizontal direction sequential driving operation that sequentially drives the light source blocks, e.g., light source blocks B1, B2and B3, included in the selected light source row, e.g., light source row LSR11, may be performed. Thus, the block shift time may be determined by dividing the latency time LT by the number of the light source blocks, e.g., light source blocks B1, B2and B3, included in each light source row in each horizontal region, e.g., horizontal region HR1. That is, the block shift time in the display device100that performs the operation illustrated inFIG. 15may correspond to a multiplication of the block shift time in the display device100that performs the operation illustrated inFIG. 3by the number of the horizontal regions HR1, HR2and HR3. Accordingly, in the display device100that performs the operation illustrated inFIG. 15, the luminance influence of the adjacent light source block on each light source block may be reduced, and a waterfall phenomenon may be prevented or reduced while local dimming is performed.

FIG. 17is a flowchart of an operation of a display device according to an example embodiment.FIG. 18is a diagram of an operation of a backlight unit of a display device performing an operation ofFIG. 17according to an example embodiment.

Referring toFIGS. 1 and 17, the panel driver120of the display device100may receive input image data IDAT in an operation S1010, and may drive the display panel110based on the input image data IDAT in an operation S1030.

The backlight driver170may divide the backlight unit160into horizontal regions in an operation S1050, and may perform a vertical direction scan operation and a horizontal direction sequential driving operation in each horizontal region. Compared with a display device100performing an operation illustrated inFIG. 15, the display device100performing an operation illustrated inFIG. 17may further perform a frame inversion operation. Thus, to perform the horizontal direction sequential driving operation in each horizontal region, the backlight driver170of the display device100performing the operation illustrated inFIG. 17may sequentially drive the light source blocks in a selected light source row within the horizontal region in a first horizontal direction in an odd-numbered frame in an operation S1070: ODD FRAME, and in an operation S1080, and may sequentially drive the light source blocks in the selected light source rows within the horizontal region in a second horizontal direction opposite to the first horizontal direction in an even-numbered frame in the operation S1070: EVEN FRAME, and in an operation S1090.

For example, as illustrated as a graph1110inFIG. 18, in each of the horizontal regions HR1, HR2and HR3, the vertical direction scan operation and the horizontal direction sequential driving operation in the first horizontal direction from a left light source block to a right light source block may be performed in the odd-numbered frame. Further, as illustrated as a graph1130inFIG. 18, in each of the horizontal regions HR1, HR2and HR3, the vertical direction scan operation and the horizontal direction sequential driving operation in the second horizontal direction from the right light source block to the left light source block may be performed in the even-numbered frame. Accordingly, in the display device100that performs the operation illustrated inFIG. 17, the frame inversion operation may be further performed, and a waterfall phenomenon may be further prevented or reduced while local dimming is performed.

FIG. 19is a flowchart of an operation of a display device according to an example embodiment.FIG. 20is a diagram of an operation of a backlight unit of a display device performing an operation ofFIG. 19according to an example embodiment.FIG. 21is a diagram of an operation of a backlight unit of a display device performing an operation ofFIG. 19according to an example embodiment.

Referring toFIGS. 1 and 19, the panel driver120of the display device100may receive input image data IDAT in an operation S1210, and may drive the display panel110based on the input image data IDAT in an operation S1230.

The backlight driver170may divide the backlight unit160into horizontal regions in an operation S1250, may perform a vertical direction scan operation and a horizontal direction sequential driving operation in each horizontal region, and may further perform a frame inversion operation. Unlike the display device100performing an operation illustrated inFIG. 17, the display device100performing an operation illustrated inFIG. 19may group light source rows of the backlight unit160into two light source groups, and may perform, in each horizontal region, the horizontal direction sequential driving operation in different horizontal directions with respect to the two light source groups.

In some example embodiments, as illustrated inFIG. 20, the backlight driver170may group the light source rows into an odd-numbered light source row group and an even-numbered light source row group. As illustrated as a graph1310inFIG. 20, to perform the horizontal direction sequential driving operation in each of the horizontal regions HR1, HR2and HR3in an odd-numbered frame, the backlight driver170may sequentially drive the light source blocks in a selected light source row belonging to the odd-numbered light source row group in each horizontal region HR1, HR2and HR3in a first horizontal direction from a left light source block to a right light source block, and may sequentially drive the light source blocks in the selected light source row belonging to the even-numbered light source row group in each horizontal region HR1, HR2and HR3in a second horizontal direction from the right light source block to the left light source block in an operation S1270: ODD FRAME, and in an operation S1280. Further, as illustrated as a graph1330inFIG. 20, to perform the horizontal direction sequential driving operation in each of the horizontal regions HR1, HR2and HR3in an even-numbered frame, the backlight driver170may sequentially drive the light source blocks in the selected light source row belonging to the odd-numbered light source row group in each horizontal region HR1, HR2and HR3in the second horizontal direction, and may sequentially drive the light source blocks in the selected light source row belonging to the even-numbered light source row group in each horizontal region HR1, HR2and HR3in the first horizontal direction in the operation S1270: EVEN FRAME, and in an operation S1290.

In other example embodiments, as illustrated inFIG. 21, the backlight driver170may group (4K+1)-th and (4K+2)-th light source rows of the light source rows into a first light source row group, and may group (4K+3)-th and (4K+4)-th light source rows of the light source rows into a second light source row group, where K is an integer greater than 0. As illustrated as a graph1350inFIG. 21, to perform the horizontal direction sequential driving operation in each of the horizontal regions HR1, HR2and HR3in the odd-numbered frame, the backlight driver170may sequentially drive the light source blocks in the selected light source row belonging to the first light source row group in each horizontal region HR1, HR2and HR3in the first horizontal direction, and may sequentially drive the light source blocks in the selected light source row belonging to the second light source row group in each horizontal region HR1, HR2and HR3in the second horizontal direction in the operation S1270: ODD FRAME, and in the operation S1280. Further, as illustrated as a graph1370inFIG. 21, to perform the horizontal direction sequential driving operation in each of the horizontal regions HR1, HR2and HR3in the even-numbered frame, the backlight driver170may sequentially drive the light source blocks in the selected light source row belonging to the first light source row group in each horizontal region HR1, HR2and HR3in the second horizontal direction, and may sequentially drive the light source blocks in the selected light source row belonging to the second light source row group in each horizontal region HR1, HR2and HR3in the first horizontal direction in the operation S1270: EVEN FRAME, and in the operation S1290.

FIG. 22is a flowchart of an operation of a display device according to an example embodiments.FIG. 23is a diagram of an operation of a backlight unit of a display device performing an operation ofFIG. 22according to an example embodiment.

Referring toFIGS. 1 and 22, the panel driver120of the display device100may receive input image data IDAT in an operation S1410, and may drive the display panel110based on the input image data IDAT in an operation S1430.

The backlight driver170may divide the backlight unit160into horizontal regions in an operation S1450, may perform a vertical direction scan operation and a horizontal direction sequential driving operation in each horizontal region, and may further perform a frame inversion operation. Unlike the display device100performing an operation illustrated inFIG. 17, the display device100performing an operation illustrated inFIG. 22may perform the horizontal direction sequential driving operation in different horizontal directions with respect to an odd-numbered horizontal region and an even-numbered horizontal region.

In some example embodiments, as illustrated as a graph1510inFIG. 23, to perform the horizontal direction sequential driving operation in an odd-numbered frame, the backlight driver170may sequentially drive light source blocks in a selected light source row within the odd-numbered horizontal region HR1and HR3in a first horizontal direction from a left light source block to a right light source block, and may sequentially drive the light source blocks in the selected light source row within the even-numbered horizontal region HR2in a second horizontal direction from the right light source block to the left light source block in an operation S1470: ODD FRAME, and in an operation S1480. Further, as illustrated as a graph1530inFIG. 23, to perform the horizontal direction sequential driving operation in an even-numbered frame, the backlight driver170may sequentially drive the light source blocks in the selected light source row within the odd-numbered horizontal region HR1and HR3in the second horizontal direction, and may sequentially drive the light source blocks in the selected light source row within the even-numbered horizontal region HR2in the first horizontal direction in the operation S1470: EVEN FRAME, and in an operation S1490.

FIG. 24is a flowchart of an operation of a display device according to an example embodiment.FIG. 25is a diagram of an operation of a backlight unit of a display device performing an operation ofFIG. 24according to an example embodiment.FIG. 26is a diagram of an operation of a backlight unit of a display device performing an operation ofFIG. 24according to an example embodiment.FIG. 27is a diagram of an operation of a backlight unit of a display device performing an operation ofFIG. 24according to an example embodiment.

Referring toFIGS. 1 and 24, the panel driver120of the display device100may receive input image data IDAT in an operation S1610, and may drive the display panel110based on the input image data IDAT in an operation S1630.

The backlight driver170may divide the backlight unit160into horizontal regions in an operation S1650, may perform a vertical direction scan operation and a horizontal direction sequential driving operation in each horizontal region, and may further perform a frame inversion operation, and may further perform the horizontal direction sequential driving operation in different horizontal directions with respect to an odd-numbered horizontal region and an even-numbered horizontal region in operations S1670, S1680and S1690. In the display device100performing an operation illustrated inFIG. 24, unlike the display device100performing an operation illustrated inFIG. 22, the horizontal direction sequential driving operation in the odd-numbered horizontal region and the horizontal direction sequential driving operation in the even-numbered horizontal region may have different start time points and/or different block shift times. In the display device100performing the operation illustrated inFIG. 22, light source blocks adjacent to boundaries of the horizontal regions may substantially simultaneously emit light. However, in the display device100performing the operation illustrated inFIG. 24, the light source blocks adjacent to the boundaries of the horizontal regions may emit light at different time points.

In an embodiment, as illustrated inFIG. 25, the horizontal direction sequential driving operation in the odd-numbered horizontal region HR1and HR3and the horizontal direction sequential driving operation in the even-numbered horizontal region HR2may have different start time points. For example, as illustrated as graphs1710and1720inFIG. 25, the start time point of the horizontal direction sequential driving operation in the even-numbered horizontal region HR2may be delayed compared with the start time point of the horizontal direction sequential driving operation in the odd-numbered horizontal region HR1and HR3. For example, the vertical direction scan operation and the horizontal direction sequential driving operation in the odd-numbered horizontal region HR1and HR3may be initiated at a time point at which a vertical start signal STV is generated, and the vertical direction scan operation and the horizontal direction sequential driving operation in the even-numbered horizontal region HR2may be initiated after a predetermined time from the time point at which the vertical start signal STV is generated.

In other example embodiments, as illustrated inFIG. 26, the horizontal direction sequential driving operation in the odd-numbered horizontal region HR1and HR3and the horizontal direction sequential driving operation in the even-numbered horizontal region HR2may have different block shift times. For example, as illustrated as graphs1730and1740inFIG. 26, the block shift time of the horizontal direction sequential driving operation in the even-numbered horizontal region HR2may be longer than the block shift time of the horizontal direction sequential driving operation in the odd-numbered horizontal region HR1and HR3. Thus, a duration of the horizontal direction sequential driving operation for each light source row in the even-numbered horizontal region HR2may be longer than a duration of the horizontal direction sequential driving operation for each light source row in the odd-numbered horizontal region HR1and HR3, and a line representing the horizontal direction sequential driving operation for each light source row in the even-numbered horizontal region HR2may have a relatively steep slope in the graphs1730and1740.

In an embodiment, as illustrated inFIG. 27, the horizontal direction sequential driving operation in the odd-numbered horizontal region HR1and HR3and the horizontal direction sequential driving operation in the even-numbered horizontal region HR2may have the different start time points and the different block shift times. For example, as illustrated as graphs1750and1760inFIG. 27, the start time point of the horizontal direction sequential driving operation in the even-numbered horizontal region HR2may be delayed compared with the start time point of the horizontal direction sequential driving operation in the odd-numbered horizontal region HR1and HR3, and the block shift time of the horizontal direction sequential driving operation in the even-numbered horizontal region HR2may be longer than the block shift time of the horizontal direction sequential driving operation in the odd-numbered horizontal region HR1and HR3. Accordingly, the light source blocks adjacent to the boundaries of the horizontal regions HR1, HR2and HR3may emit light at different time points.

FIG. 28is a block diagram of an electronic device2100including a display device2160according to an example embodiments

Referring toFIG. 28, the electronic device2100may include a processor2110, a memory device2120, a storage device2130, an input/output (I/O) device2140, a power supply2150, and the display device2160. The electronic device2100may further include ports for communicating with a video card, a sound card, a memory card, a universal serial bus (USB) device, or other electric devices.

The processor2110may perform various computing functions or tasks. The processor2110may be an application processor (AP), a micro processor, a central processing unit (CPU), etc. The processor2110may be coupled to other components via an address bus, a control bus, a data bus, etc. Further, in some example embodiments, the processor2110may be further coupled to an extended bus such as a peripheral component interconnection (PCI) bus.

The storage device2130may be a solid-state drive (SSD) device, a hard disk drive (HDD) device, a CD-ROM device, etc. The I/O device2140may include an input device such as a keyboard, a keypad, a mouse, a touch screen, etc, and/or an output device such as a printer, a speaker, etc. The power supply2150may supply power for operations of the electronic device2100. The display device2160may be coupled to other components through the buses or other communication links.

The display device2160may perform a vertical direction scan operation that sequentially selects light source rows included in a backlight unit, and a horizontal direction sequential driving operation that sequentially drives light source blocks included in a selected light source row. Accordingly, a waterfall phenomenon where a relatively high or low luminance horizontal line image exists or gradually moves may be prevented or reduced while local dimming is performed.

The inventive concepts may be applied to any display device2160, and any electronic device2100including the display device2160. For example, the inventive concepts may be applied to a television (TV), a digital TV, a 3D TV, a smart phone, a wearable electronic device, a tablet computer, a mobile phone, a personal computer (PC), a home appliance, a laptop computer, a personal digital assistant (PDA), a portable multimedia player (PMP), a digital camera, a music player, a portable game console, a navigation device, etc.