KR20230099980A - Display device - Google Patents

Abstract

A display device according to an exemplary embodiment of the present invention is divided into a plurality of blocks and driven for each of the divided blocks, and each block includes a backlight unit including a plurality of light source packages and disposed above the backlight unit. A display panel and a control unit outputting a local dimming value for each block corresponding to brightness of each block of the backlight unit according to an image displayed on the display panel, wherein the control unit includes a shadow in a low power driving mode. For an image, a representative color is extracted and a data voltage corresponding to a solid color is controlled to be transmitted to a corresponding sub-pixel of the display panel, and the brightness of each block of the backlight unit corresponding to the image is determined based on the shade. Images can be expressed by local dimming. As a result, it is possible to reduce power consumption while improving image contrast.

Description

Display device {DISPLAY DEVICE}

The present invention relates to a display device, and more particularly, to a display device using a light emitting diode (LED) as a backlight source.

A liquid crystal display (LCD) displays an image by controlling light transmittance of a liquid crystal using an electric field. Since the liquid crystal display device is not self-luminous, a backlight unit is provided to provide light to the rear surface of the liquid crystal display panel on which an image is displayed.

Depending on the arrangement of the light source, the backlight unit is a direct light type that radiates light to the liquid crystal panel from a plurality of light source packages installed on the rear surface of the liquid crystal display device, and a backlight unit installed on the sidewall of a light guide plate (LGP). It can be largely classified into an edge light type that transmits light from a plurality of light source packages to a liquid crystal panel.

An object to be solved by the present invention is to provide a display device capable of reducing the power consumption of a liquid crystal panel.

The tasks of this specification are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the description below.

In order to solve the above problems, a display device according to an exemplary embodiment of the present invention is divided into a plurality of blocks and driven for each of the divided blocks, and each block includes a backlight unit including a plurality of light source packages. , a display panel disposed above the backlight unit and a control unit outputting a local dimming value for each block corresponding to the brightness of each block of the backlight unit according to an image displayed on the display panel, wherein the control unit, In the low-power driving mode, representative colors are extracted for an image including shadows, data voltages corresponding to solid colors are controlled to be transmitted to corresponding sub-pixels of the display panel, and blocks of the backlight unit corresponding to the image An image may be expressed by local dimming each brightness based on the shade.

Details of other embodiments are included in the detailed description and drawings.

In the low-power driving mode, the representative color is extracted from an image including shadows and expressed as a solid color, and the contrast of the image is reduced by using a partial driving method of local dimming. ) and at the same time reduce power consumption.

Effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the present invention.

1 is a schematic cross-sectional view of a display device according to an exemplary embodiment of the present invention.
FIG. 2 is a plan view schematically illustrating the backlight unit of FIG. 1 .
FIG. 3 is a block diagram schematically illustrating the configuration of the display device of FIG. 1 .
FIG. 4 is another block diagram schematically showing the configuration of the display device of FIG. 1 .
5 is a diagram showing an input image as an example.
6A to 6C are diagrams showing an image processing method of the present invention as an example.
7 is a flowchart sequentially showing an image processing method according to the present invention.
8 is a diagram showing an input image as an example.
9A to 9C are diagrams showing grayscale images of the input image of FIG. 8 as examples.
10A to 10C are diagrams showing binary images of the gray scale images of FIGS. 9A to 9C as examples.
FIG. 11 is a diagram showing aligned labels for the binary images of FIGS. 10A to 10C as an example.
FIG. 12 is a diagram showing a solid color map according to FIG. 11 as an example.
FIG. 13 is a diagram showing a local dimming map corresponding to the solid color map of FIG. 12 .
14 is a block diagram schematically showing the configuration of a backlight driver.
15 is a block diagram showing the configuration of a backlight driver in more detail.

The advantages and features of the present invention, and how to achieve them, will become clear with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different shapes, only these embodiments make the disclosure of the present invention complete, and common knowledge in the art to which the present invention pertains. It is provided to completely inform the person who has the scope of the invention, and the present invention is only defined by the scope of the claims.

The shapes, areas, ratios, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of the present invention are illustrative, and the present invention is not limited thereto. Like reference numbers designate like elements throughout the specification. In addition, in describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. In the case where 'includes', 'has', 'consists of', etc. mentioned above is used, other parts may be added unless 'only' is used. In the case where a component is expressed in the singular, the case including the plural is included unless otherwise explicitly stated.

In interpreting the components, even if there is no separate explicit description, it is interpreted as including the error range.

In the case of a description of a positional relationship, for example, when the positional relationship of two parts is described with '~ above', '~ above', '~ below', 'next to', etc., 'directly' or Unless 'directly' is used, one or more other parts may be placed between two parts.

When an element or layer is referred to as being “on” another element or layer, it includes all cases where another element or layer is directly on top of another element or another layer or other element intervenes therebetween.

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

Like reference numbers designate like elements throughout the specification.

The area and thickness of each component shown in the drawings is shown for convenience of description, and the present invention is not necessarily limited to the area and thickness of the illustrated component.

Each feature of the various embodiments of the present invention can be partially or entirely combined or combined with each other, technically various interlocking and driving are possible, and each embodiment can be implemented independently of each other or can be implemented together in a related relationship. may be

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic cross-sectional view of a display device according to an exemplary embodiment of the present invention.

Referring to FIG. 1 , a display device 100 according to an exemplary embodiment may include a display panel 110 and a backlight unit 120 disposed on a rear surface of the display panel 110 .

Also, although not shown, the display device 100 according to an embodiment of the present invention may further include a top case and a cover bottom as a case configuration.

The top case may protect the display panel 110 from the outside. The top case may be disposed to cover an upper edge of the display panel 110 and a side surface of the display panel 110 . The top case may include a horizontal portion and a vertical portion. A horizontal portion of the top case may surround an upper edge of the display panel 110 and a vertical portion may surround a side surface of the display panel 110 surrounded by a guide panel, but is not limited thereto. The top case may be made of strong plastic or metal material to protect the display panel 110, but is not limited thereto.

The display panel 110 is a panel that displays an image. For example, the display panel 110 may be a liquid crystal display panel 110 that displays an image by adjusting light transmittance of liquid crystal. The liquid crystal display panel 110 may include a lower substrate, an upper substrate, and a liquid crystal layer filled between the lower substrate and the upper substrate.

Pixels are defined on the lower substrate by crossing a plurality of gate lines and data lines. A thin film transistor may be provided at each intersection of each pixel and connected to a pixel electrode formed in each pixel.

The common electrode controls the liquid crystal by forming an electric field with the pixel electrode. Depending on the liquid crystal alignment control method of the liquid crystal layer, the common electrode may be formed on the lower substrate or the upper substrate. For example, when liquid crystal is controlled by TN (Twisted Nematic) mode, VA (Vertical Alignment) mode, etc., a common electrode is disposed on the upper substrate, and the pixel electrode and the common electrode form a vertical electric field to control the liquid crystal. there is. When liquid crystal is controlled by FFS (Fringe Field Switching) mode, IPS (In-Plane Switching) mode, etc., a common electrode is disposed on the lower substrate, and the pixel electrode and the common electrode form a horizontal electric field to control the liquid crystal. .

A color filter and a black matrix may be disposed on the upper substrate. Light emitted from the backlight unit 120 may pass through a liquid crystal layer and a color filter between the lower substrate and the upper substrate and be converted into light of various colors. The black matrix may cover a gate line, a data line, or a thin film transistor disposed on the lower substrate so as not to be visually recognized.

A driver for driving the display panel 110 may be disposed along one side of the display panel 110 . The driving unit may include various ICs such as gate driver ICs or data driver ICs and driving circuits. The driver may apply signals to the gate line and the data line to drive the display panel 110 . The driver may be electrically connected to the display panel 110 through a connecting member. For example, the connection member may be made of COF (Chip On Film) or TCP (Tape Carrier Package), but is not limited thereto.

The guide panel supports the display panel 110 under the display panel 110 . Specifically, the guide panel) may be formed in a rectangular frame shape to support an edge of the lower surface of the display panel 110 . The guide panel may include a vertical portion and a horizontal portion. The vertical portion of the guide panel may be disposed to surround the side surface of the display panel 110 and be in contact with the vertical portion of the top case, and the horizontal portion may be disposed to protrude from the vertical portion and surround the edge of the lower surface of the display panel 110 . , but not limited thereto.

The backlight unit 120 may supply light to the display panel 110 . The backlight unit 120 may include a plurality of optical sheets, a diffusion plate, a plurality of light source packages, and a printed circuit board. The backlight unit 120 of FIG. 1 is a direct type backlight unit, and a plurality of light source packages may be disposed below the display panel 110 .

As in the present invention, since the direct type backlight unit 120 is configured such that the plurality of light source packages face the display panel 110, relatively more light sources can be disposed than the edge type backlight unit. Also, in the direct type backlight unit 120 , a plurality of light source packages may be individually driven.

Accordingly, the direct-type backlight unit 120 may implement an excellent contrast ratio through local dimming driving. In addition, the direct-type backlight unit 120 further increases the luminance of the light source package corresponding to the area where the bright screen is displayed, thereby increasing the contrast ratio between the bright screen and the dark screen. A dynamic image can be realized.

The plurality of optical sheets diffuses or condenses the light emitted from the plurality of light source packages so that light in a uniform planar shape is incident on the display panel 110 . The plurality of optical sheets may include a diffusion sheet and at least one light collecting sheet.

The diffusion plate may be disposed between the plurality of optical sheets and the plurality of light source packages. The diffusion plate may diffuse the light emitted from the plurality of light source packages so that the light is incident on the plurality of optical sheets.

A plurality of light source packages emit white light. Light emitted from the plurality of light source packages passes through the diffusion plate and the plurality of optical sheets, and may be evenly supplied to the entire surface of the display panel 110 . Specifically, the light source package may function as a surface-emitting light source package so that light is evenly supplied to the entire surface of the display panel 110 . A more detailed description of the light source package will be described later with reference to FIG. 2 .

A plurality of light source packages may be mounted on the printed circuit board. The printed circuit board may be electrically connected to each of the plurality of light source packages to apply voltage to the light source packages.

The cover bottom may accommodate the backlight unit 120 . Also, the cover bottom may emit heat generated in the light source package to the outside. A reflective sheet for reflecting light from the light source package to the front surface may be attached to the bottom surface of the cover bottom.

FIG. 2 is a plan view schematically illustrating the backlight unit of FIG. 1 .

FIG. 2 schematically shows the arrangement of a plurality of light source packages in the backlight unit 120 of FIG. 1 .

Referring to FIG. 2 , the backlight unit 120 may be composed of a plurality of blocks 170 made of a plurality of light source packages. That is, one block 170 may include a plurality of light source packages, and the backlight unit 120 includes N and M blocks 170 in the X-axis and Y-axis directions, respectively (N and M are 1 or more natural numbers) may be arranged in the form of a matrix.

Each block 170 is driven by a direct backlight method, and each block 170 operates as one light source, and a plurality of blocks 170 are arranged in a direct backlight method to provide backlight unit 120. can be configured.

Accordingly, the thickness of the light guide plate can be reduced and the number of optical films can be reduced, so that the backlight unit 120 can be slimmed down.

For example, 60 and 26 blocks 170 may be arranged in the X-axis and Y-axis directions, respectively, so that a total of 1560 blocks 170 may be arranged in a matrix form.

For example, 2X3, that is, 6 light source packages may be disposed in each block 170, but is not limited thereto.

Each block 170 may be manufactured as an independent assembly, and may configure the modular backlight unit 120 by being closely arranged. The modular backlight unit 120 as described above may provide light to the display panel as a backlight unit.

The backlight unit 120 according to an embodiment of the present invention may be driven by a partial driving method such as a full driving method or a local dimming method or an impulsive method. A driving method of the light source package may be variously changed according to circuit design, but is not limited thereto.

When driven in the partial driving method, the contrast ratio is increased and images for the bright and dark parts of the screen can be clearly expressed, resulting in an improvement in image quality. That is, since the backlight unit 120 can be divided into a plurality of blocks 170 and driven for each of the divided blocks 170, the luminance of each of the divided blocks 170 is linked to the luminance of the video signal to obtain an image quality. Contrast ratio and sharpness can be improved by decreasing luminance of dark areas and increasing luminance of bright areas.

Also, when the backlight unit 120 is driven in a local dimming method, the display panel may have a plurality of divided regions corresponding to each of the blocks 170 of the backlight unit 120, and each of the divided regions of the display panel The brightness of light emitted from each block 170 of the backlight unit 120 may be adjusted according to a luminance level of the luminance level, for example, a peak value of a gray level or a color coordinate signal.

The backlight unit 120 according to an embodiment of the present invention has an effect of cost reduction by reducing power consumption by applying a partial driving method. In addition, since the backlight unit 120 according to an embodiment of the present invention is manufactured by assembling a plurality of blocks 170, the manufacturing process of the backlight unit 120 is simple and loss that may occur during the assembly process is minimized. This can improve productivity. In addition, it is possible to reduce defects due to light guide plate scratches that may occur during the assembly process of the backlight unit 120 and to improve optical mura, thereby improving process reliability and quality.

In addition, the backlight unit 120 according to an embodiment of the present invention has an effect that can be applied to backlight units of various sizes by standardizing and mass-producing the blocks 170 .

In addition, when a defect occurs in any one of the blocks 170 of the backlight unit 120 according to an embodiment of the present invention, only the defective block 170 is replaced without replacing the entire backlight unit 120. Therefore, the replacement work is easy and the cost of replacing parts is reduced.

In addition, the backlight unit 120 according to an embodiment of the present invention is robust against external shocks or environmental changes and has excellent durability.

In addition, the backlight unit 120 according to an exemplary embodiment of the present invention can be easily applied to a large display panel and has an advantageous effect on slimming the display device.

The block 170 is a basic unit to which driving power is supplied to the backlight unit 120, more specifically, a plurality of light source packages provided in the backlight unit 120 to emit light, that is, one block 170 A plurality of included light source packages are simultaneously turned on or turned off, and can emit light having the same luminance when turned on. In addition, a plurality of light source packages included in different blocks 170 of the backlight unit 120 may receive different driving powers and emit light having different luminance.

FIG. 3 is a block diagram schematically illustrating the configuration of the display device of FIG. 1 .

Among the configurations of the display device shown in FIG. 3, a description of the same components as those described with reference to FIGS. 1 and 2 will be omitted.

Referring to FIG. 3 , the display device according to an exemplary embodiment of the present invention includes a control unit 160, a backlight unit (hereinafter referred to as 'BLU') driving unit 140, a panel driving unit 130, and a backlight unit 120. ) and the display panel 110 .

In the display panel 110, images may be displayed at 60, 120, or 240 frames per second, and as the number of frames per second increases, the frame scan period decreases.

At this time, the panel driver 130 may receive various control signals and image signals from the control unit 160 to generate driving signals for driving the display panel 110 and supply them to the display panel 110 . For example, the panel driver 130 may include a gate driver connected to a gate line of the display panel 110, a data driver connected to a data line, and a timing controller controlling them.

Meanwhile, the control unit 160 transmits a local dimming value according to the video signal to the BLU driver 140 so that the luminance of the backlight unit 120, that is, the light source packages included in the backlight unit 120, is controlled in response to the video signal. can be printed out.

In addition, the controller 160 may provide information about a scan period in which one frame is displayed on the display panel 110 , for example, a vertical synchronization signal to the BLU driver 140 .

At this time, the BLU driving unit 140 drives the light source packages included in the backlight unit 120 according to the input scan period, and controls light to be emitted from the light source packages in synchronization with the display of an image on the display panel 110. can do.

Meanwhile, each of the light source packages included in the backlight unit 120 may include a plurality of point light sources, for example, a light emitting diode (LED), and the plurality of point light sources included in one block are simultaneously It can be turned on or turned off.

Meanwhile, according to an embodiment of the present invention, a plurality of light source packages provided in the backlight unit 120 are divided into a plurality of blocks by a division driving method such as local dimming as described above, and the divided blocks The luminance of the light source packages belonging to each block may be adjusted according to the luminance level of the region of the display panel 110 corresponding to each block, for example, a gray level peak value or a color coordinate signal.

For example, when an image is displayed on the first area of the display panel 110 and no image is displayed on the second area, that is, it is displayed in black, the BLU driving unit 140 removes the second area from among the divided blocks. Light source packages included in the backlight unit 120 may be controlled so that light source packages belonging to blocks corresponding to region 2 emit light having a lower luminance than light source packages belonging to blocks corresponding to region 1 .

Meanwhile, light source packages belonging to a block of the backlight unit 120 corresponding to a second area of the display screen of the display panel 110 that is not displayed and displayed in black may be turned off, Accordingly, power consumption of the display device may be further reduced.

That is, the controller 160 controls the local dimming value corresponding to the brightness of each block of the backlight unit 120 according to the luminance level of the input video signal, for example, the luminance level of the entire image or the luminance level of a specific region, that is, A local dimming value for each block is generated and output to the BLU driver 140 , and the BLU driver 140 may control the brightness of each block of the backlight unit 120 using the input local dimming value for each block.

Hereinafter, a method of driving a display device according to an exemplary embodiment of the present invention will be described in more detail with reference to FIGS. 4 to 7 .

FIG. 4 is another block diagram schematically showing the configuration of the display device of FIG. 1 .

Among the configurations of the display device shown in FIG. 4 , a description of the same components as those described with reference to FIGS. 1 to 3 will be omitted.

Referring to FIG. 4 , the display device according to an exemplary embodiment of the present invention includes an image analyzer 165 that receives an RGB image signal and determines a black region for the entire image or a partial region, and the remaining region except for the black region. A solid color map generating unit 161 generating a solid color map for the black area and a local dimming map generating unit 162 generating a local dimming map for remaining areas except for the black area.

In addition, the display device according to an embodiment of the present invention outputs a driving signal to the display panel 110 so that an image is output according to the R'G'B' signal generated by the solid color map generator 161. A driving unit 130 may be further included.

The display device according to an exemplary embodiment of the present invention may further include a BLU driver 140 that drives the backlight unit 120 according to the brightness level determined by the local dimming map generator 162 .

The image analyzer 165 divides an image region into a plurality of regions for an input RGB image signal, and maps the local dimming map to determine the brightness of light source packages belonging to blocks of the backlight unit 120 corresponding to each region. Information on the luminance level of the image may be provided to the generator 162 .

For example, the information on the luminance level of the image provided from the image analyzer 165 to the local dimming map generator 162 is the average luminance level (Average Block Level) of an area corresponding to a corresponding block whose brightness is to be determined. ; ABL) as well as the average luminance level (APL) of other adjacent areas or the entire area of the image.

That is, the image analyzer 165 divides the image of one frame into a plurality of regions, and transmits information on the average luminance level of the divided first region as well as the average luminance level of other regions adjacent to the first region to the local area. It may be provided to the dimming map generation unit 162 . However, the present invention is not limited thereto, and the image analyzer 165 provides information about the average luminance level of the entire image when the local dimming map generator 162 determines the brightness of a specific block of the backlight unit 120. You can also provide that information to use.

According to an embodiment of the present invention, it is necessary to provide a look-up table for determining the brightness of a specific block of the backlight unit 120 according to the average luminance level of the entire or partial region of the measured image, and a local dimming map The generator 162 may extract and output brightness of light source packages corresponding to the average luminance level measured by the image analyzer 165 from a look-up table.

For example, when the average luminance level of the entire image is equal to or greater than the predetermined 'B' value, the entire image should be expressed in a bright grayscale, and the brightness of a corresponding block of the backlight unit 120 may be determined. In this case, since the image to be displayed on the display panel 110 is generally bright, the phenomenon of darkening of the screen is not a big problem while maximizing the local dimming effect of the backlight unit 120 . According to another expression, when the image is to be expressed in a bright grayscale as a whole, the higher the average luminance level measured for each divided region of the image is, the higher the brightness of the corresponding block is determined, and the smaller the average luminance level of the divided region is, the higher the brightness of the corresponding block is. The brightness of the corresponding block may be determined to be low.

On the other hand, if the entire image is to be expressed in a dark grayscale, that is, if the average luminance level of the entire image is less than the 'A' value, local dimming may be performed only on the divided area having an average luminance level smaller than the preset luminance value. there is. That is, the proposed look-up table may be set so that local dimming in which the brightness of the light source package is changed is performed only for a divided region having an average luminance level lower than a predetermined luminance value. This is because, when the overall image is a dark image, if the brightness of the light source is determined according to the local dimming graph, the brightness of the image becomes too dark and color reproducibility is rather deteriorated.

Therefore, when the luminance level of the entire image is low, local dimming is not performed on the divided regions having an average luminance level equal to or greater than a predetermined brightness level.

And, when the average luminance level of the entire image is located between the 'A' value and the 'B' value, if the average luminance level of the segmented area to be measured is greater than the preset value, the change in brightness of the light source package is small, When the average luminance level of the divided regions is less than a predetermined value, the brightness change of the light source package may be set to be large. That is, a local dimming value corresponding to the light source may be reduced for divided areas having a bright grayscale, and a local dimming value corresponding to the light source may be relatively increased for divided areas having a lower grayscale.

Meanwhile, the image analyzer 165 according to an embodiment of the present invention determines whether a black region exists in the entire image or a partial region, and uses the solid color map generator 161 to determine the solid color for the remaining region except for the black region. It is characterized in that a (solid color) map is generated and provided to the panel driver 130 . By outputting an image using the backlight unit 120 driven by the aforementioned local dimming method, power consumption can be further reduced in the low power driving mode.

That is, in a user environment, patterns containing shadows are driven more often than solid patterns.

For reference, a solid pattern means a pattern consisting of a single color, and if there is a curve on the surface of an object, a change in spatial contrast occurs when a light source acts, and this variation in brightness of light can be called shade. there is.

Patterns that contain these solid pattern contrast shading data Power consumption of the display panel is high due to data transition.

In particular, in the case of an IPS panel, a black screen is brightly expressed due to the luminance of the backlight, and the contrast ratio may be weaker than that of an OLED panel. Accordingly, as described above, the contrast ratio may be improved by using a local dimming technique in which the luminance of the LED is higher in a bright area and the luminance of the LED is darker in a dark area. However, in the case of the local dimming technology, although the contrast ratio can be increased, there is a disadvantage in that logic power consumption is high because many changes occur in driving-related data of the display panel. That is, the driving power consumption of the display panel may increase due to the data change in the shaded area.

Accordingly, the present invention focuses on the fact that the power consumption related to driving of the display panel is reduced because the solid pattern has a small data change compared to a pattern containing shadows, and expresses a gradation based on a solid pattern in a low power driving mode. Thus, power consumption related to driving of the display panel is reduced.

5 is a diagram showing an input image as an example.

6A to 6C are diagrams showing an image processing method of the present invention as an example.

FIG. 5 shows an example of an input image for an entire image or a partial region, that is, an input image of a green pattern including shades.

First, in the low power driving mode, the timing controller may recognize a gradation region of an input image.

Thereafter, after analyzing RGB/gray level data, a representative color as shown in FIG. 6A may be derived. In this case, a green solid color map can be created.

In addition, to implement a gradation, a local dimming map as shown in FIG. 6B may be generated using a local dimming technique to control the luminance of LEDs according to luminance data.

Accordingly, it is possible to secure the effect of reducing power consumption in addition to the existing contrast ratio increase. That is, it is possible to reduce the power consumption caused by data conversion. For example, in the case of solid white compared to white gradation (~360mA) at 120Hz and white color, only 300mA is consumed, reducing power consumption by about 17%. do.

Hereinafter, the image processing method of the present invention will be described in more detail with reference to FIGS. 7 to 13 .

7 is a flowchart sequentially showing an image processing method according to the present invention.

8 is a diagram showing an input image as an example.

9A to 9C are diagrams showing grayscale images of the input image of FIG. 8 as examples.

10A to 10C are diagrams showing binary images of the gray scale images of FIGS. 9A to 9C as examples.

FIG. 11 is a diagram showing aligned labels for the binary images of FIGS. 10A to 10C as an example.

FIG. 12 is a diagram showing a solid color map according to FIG. 11 as an example.

FIG. 13 is a diagram showing a local dimming map corresponding to the solid color map of FIG. 12 .

Referring to FIG. 7 , the display device according to an embodiment of the present invention may receive RGB image signals from a tuner, a graphic card, or the like (S110). That is, for example, as shown in FIG. 8 , RGB image signals for the entire image or a partial region may be input.

8 shows a red image pattern including shade in the 1/4 quadrant, a blue image pattern including shade in the 2/4 quadrant, and a green image pattern including shade in the 3/4 quadrant. , a case in which there is a white image pattern including shadows in the 4/4 quadrant is shown as an example.

Next, a black region in the image may be extracted from the received RGB image signal (S120). Since the black area does not require image processing, it is possible to smoothly process the image by removing it in advance. A black region may be extracted from an input image and grouping may be performed on the remaining regions.

Next, a black region may be extracted from the input image and an image of the remaining region may be converted into a gray scale image (S130).

That is, as in FIGS. 9A to 9C , the input image may be converted into gray scale images (Grayscale_Red, Grayscale_Green, Grayscale_Blue) for each red, green, and blue color. 9A, 9B, and 9C respectively show a red gray scale image (Grayscale_Red), a green gray scale image (Grayscale_Green), and a blue gray scale image (Grayscale_Blue) of the input image of FIG. 8 as examples.

Referring to FIG. 9A , for example, Grayscale_Red may be converted into a gray scale image in 1/4 and 4/4 quadrants.

Referring to FIG. 9B , for example, Grayscale_Green may be converted into a gray scale image in 3/4 and 4/4 quadrants.

Referring to FIG. 9C , for example, Grayscale_Blue may be converted into a gray scale image in the 2/4 and 4/4 quadrants.

Next, the gray scale image may be converted into a binary image, and labeling may be performed on the converted image (S140).

That is, as shown in FIGS. 10A to 10C , the gray scale images (Grayscale_Red, Grayscale_Green, and Grayscale_Blue) of FIGS. 9A to 9C may be converted into binary images using a threshold. In addition, labeling may be performed within each group in the converted binary image.

For example, referring to FIG. 10A , Grayscale_Red may be labeled as Label_R_2 and Label_R_1 in the first and fourth quadrants, respectively.

Also, referring to FIG. 10B , Grayscale_Green may be labeled as Label_G_2 and Label_G_1 in the 3/4 quadrant and the 4/4 quadrant, respectively.

Also, referring to FIG. 10C , Grayscale_Blue may be labeled as Label_B_2 and Label_B_1 in the second and fourth quadrants, respectively.

Next, the labeling of the binary images of FIGS. 10A to 10C may be compared to align the labels into one binary image (S150).

That is, referring to FIG. 11 , previous images of FIGS. 10A to 10C may be compared to see if there is an overlapping portion, and labels may be aligned as one binary image.

For example, quadrant 1 can have labels aligned with Label_R_2, and quadrant 2 can have labels aligned with Label_B_2.

Also, for example, quadrant 3 may align labels with Label_G_2, and quadrant 4 may align labels with Label_R_1, Label_G_1, and Label_B_1.

Next, a solid color map may be generated by extracting a representative color based on the aligned labels (S150-S160). That is, a solid color map may be generated by extracting a representative color as a color of overlapping labels.

Therefore, referring to FIG. 12, the solid color map consists of red in the first quarter, blue in the second, green in the third, and white in the fourth. It can be.

Next, a local dimming map as shown in FIG. 13 is generated, and an output image may be output by combining the generated solid color map and the local dimming map (S170 to S180).

Hereinafter, the generation of the local dimming map will be described in detail with reference to FIGS. 14 and 15 .

14 is a block diagram schematically showing the configuration of a backlight driver.

15 is a block diagram showing the configuration of a backlight driver in more detail.

Referring to FIG. 14 , the BLU driving unit 140 receives a local dimming value for each block representing the brightness of each of the divided blocks of the backlight unit from the controller, more specifically, the local dimming map generator provided in the controller, and inputs the local dimming value for each block. A plurality of driving signals, for example, first to m th driving signals may be output using the received local dimming value for each block.

Meanwhile, each of a plurality of driving signals output from the BLU driving unit 140 may control the brightness of two or more divided blocks of the backlight unit.

That is, the BLU driving unit 140 generates first driving signals for controlling the brightness of n blocks among the blocks of the backlight unit, for example, the first to nth blocks, and belongs to the first to nth blocks. For this, the first drive signal may be generated using local dimming values corresponding to the first to nth blocks among local dimming values for each block input from the controller.

According to an embodiment of the present invention, the controller and the BLU driver 140 may transmit and receive signals using Serial Peripheral Interface (SPI) communication.

That is, the BLU driving unit 140 may receive a local dimming value for each block from the control unit using SPI communication.

Also, referring to FIG. 15 , the BLU driving unit 140 may include a plurality of driving units 141 and 145, and each of the plurality of driving units 141 and 145 is a microcontroller unit; referred to as MCUs) (142, 146) and a plurality of driver ICs (143, 147).

MCU is a type of integrated circuit (IC) that plays a role in manipulating devices or controlling processes.

For example, the first driving unit 141 includes an MCU 142 and a plurality of driver ICs 143, and the MCU 142 is a block from a control unit, more specifically, a local dimming map generator provided in the control unit. The local dimming values of the corresponding blocks may be delivered to each of the plurality of driver ICs 143 by receiving the local dimming values in serial and outputting them in parallel.

Meanwhile, each of the plurality of driver ICs 143 may control the brightness of n blocks among the divided blocks of the backlight unit, and for this purpose, a driving signal for controlling the brightness of the n blocks is transmitted using n channels. It can be output to n block LEDs 171, 172, 173, and 174, respectively.

For example, the first driving unit 141 may include 4 driver ICs 143, and each of the 4 driver ICs 143 outputs a driving signal using 16 channels, and a light source package belonging to 16 blocks. You can control their brightness. Accordingly, the first driving unit 141 may control the brightness of 4×16 blocks, that is, 64 blocks among the divided blocks of the backlight unit. However, the present invention is not limited thereto.

In addition, for example, the second driving unit 145 includes an MCU 146 and a plurality of driver ICs 147, and the MCU 146 is a control unit, more specifically, a block-by-block from a local dimming map generation unit to the control unit. The local dimming values of the corresponding blocks may be transferred to each of the plurality of driver ICs 147 by receiving the local dimming values serially and outputting them in parallel.

Meanwhile, each of the plurality of driver ICs 147 may control the brightness of n blocks among the divided blocks of the backlight unit, and for this purpose, a driving signal for controlling the brightness of the n blocks is transmitted using n channels It can be output to n block LEDs (175, 176, 177, 178), respectively.

Since the configuration of the BLU driving unit 140 shown in FIGS. 14 and 15 is only one embodiment according to the present invention, the display device according to the present invention is not limited to the configuration shown in FIGS. 14 and 15 . That is, the BLU driving unit 140 may include three or more driving units, and the number of blocks of the backlight unit controlling the brightness of each driving unit may be changed.

A display device according to embodiments of the present invention can be described as follows.

A display device according to an exemplary embodiment of the present invention is divided into a plurality of blocks and driven for each of the divided blocks, and each block includes a backlight unit including a plurality of light source packages and disposed above the backlight unit. A display panel and a control unit outputting a local dimming value for each block corresponding to brightness of each block of the backlight unit according to an image displayed on the display panel, wherein the control unit includes a shadow in a low power driving mode. For an image, a representative color is extracted and a data voltage corresponding to a solid color is controlled to be transmitted to a corresponding sub-pixel of the display panel, and the brightness of each block of the backlight unit corresponding to the image is determined based on the shade. Images can be expressed by local dimming.

According to another feature of the present invention, the control unit may include an image analysis unit for determining a black area of the entire image or a partial area, a solid color map generator for generating a solid color map, and a local dimming map for generating a local dimming map. wealth may be included.

According to another feature of the present invention, the solid color map generating unit may generate the solid color map for a region other than the black region.

According to another feature of the present invention, the local dimming map generating unit may generate the local dimming map for a remaining area except for the black area.

According to another feature of the present invention, the image analyzer divides an image region into a plurality of regions for an input RGB image signal, and provides information on a luminance level of the divided regions to the local dimming map generator to Brightness of the light source packages included in the block corresponding to the divided area may be controlled.

According to another feature of the present invention, the image analyzer may receive an RGB image signal for the entire image or the partial region.

According to another feature of the present invention, the image analyzer may extract a black region in an image from the received RGB image signal and perform grouping on the remaining regions.

According to another feature of the present invention, the image analyzer may convert the classified input image into a gray scale image for each of red, green and blue.

According to another feature of the present invention, the image analysis unit converts each gray scale image into a binary image using a reference value, and labels within each group in the converted binary image ( labeling) can be performed.

According to another feature of the present invention, the image analysis unit may align the labels into one binary image by comparing whether there is an overlap between each previous image on which the labeling was performed.

According to another feature of the present invention, the solid color map generator may generate the solid color map by extracting a representative color based on the aligned labels.

According to another feature of the present invention, the solid color map generator may extract the representative color as the color of the overlapping labels.

According to another feature of the present invention, the display device may further include a BLU driving unit that receives the local dimming value for each block and outputs a plurality of driving signals using the received local dimming value for each block. .

According to another feature of the present invention, the BLU driver may receive a local dimming value for each block from the local dimming map generator using SPI (Serial Peripheral Interface) communication.

According to another feature of the present invention, the BLU driving unit includes a plurality of driving units, and the driving units include a control unit receiving a local dimming value for each block from the control unit and driving for controlling brightness of two or more blocks. It may include a plurality of driver ICs each outputting a signal.

According to another feature of the present invention, the control unit may parallelly output the local dimming value for each block, which is input serially, and transmit the local dimming values to each of the plurality of driver ICs.

According to another feature of the present invention, the driver IC may supply driving signals to the light source packages included in the n blocks using n channels.

Although the embodiments of the present invention have been described in more detail with reference to the accompanying drawings, the present invention is not necessarily limited to these embodiments, and may be variously modified and implemented without departing from the technical spirit of the present invention. . Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain, and the scope of the technical idea of the present invention is not limited by these embodiments. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The protection scope of the present invention should be construed according to the claims below, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

100: display device
110: display panel
120: backlight unit
130: panel driving unit
140: BLU driving unit
141, 145: drive unit
142, 146: MCU
143, 147: driver IC
160: control unit
161: solid color map generation unit
162: local dimming map generator
165: image analysis unit
170: block
171-178: n block LEDs

Claims (17)

a backlight unit that is divided into a plurality of blocks and driven for each of the divided blocks, each of which includes a plurality of light source packages;
a display panel disposed above the backlight unit; and
a controller outputting a local dimming value for each block corresponding to the brightness of each block of the backlight unit according to an image displayed on the display panel;
In the low-power driving mode, the control unit extracts a representative color for an image including shadows, controls data voltages corresponding to solid colors to be transmitted to corresponding sub-pixels of the display panel, and Displaying an image by local dimming the brightness of each corresponding block of the backlight unit based on the shade. According to claim 1,
The control unit,
an image analyzer for determining a black region of the entire image or a portion of the image;
a solid color map generating unit generating a solid color map; and
A display device comprising a local dimming map generating unit generating a local dimming map. According to claim 2,
The solid color map generating unit generates the solid color map for an area other than the black area. According to claim 2,
wherein the local dimming map generation unit generates the local dimming map for an area other than the black area. According to claim 2,
The image analyzer divides an image region into a plurality of regions for an input RGB image signal, and provides information on the luminance level of the divided region to the local dimming map generator to generate the block corresponding to the divided region. A display device that controls the brightness of the included light source packages. According to claim 2,
The image analysis unit receives an RGB image signal for the entire image or the partial region as an input. According to claim 6,
The image analysis unit extracts a black region in an image from the input RGB image signal and performs grouping on the remaining regions. According to claim 7,
The image analysis unit converts the classified input image into a gray scale image for each red, green and blue color. According to claim 8,
The image analysis unit converts each gray scale image into a binary image using a reference value, and performs labeling within each group on the converted binary image. According to claim 9,
Wherein the image analysis unit aligns the labels into one binary image by comparing each previous image on which the labeling is performed to see if there is an overlapping portion. According to claim 10,
wherein the solid color map generator generates the solid color map by extracting a representative color based on the aligned labels. According to claim 11,
The solid color map generator extracts the representative color as the color of the overlapping labels. According to claim 2,
The display device further includes a BLU driving unit that receives the local dimming value for each block and outputs a plurality of driving signals using the received local dimming value for each block. According to claim 13,
The BLU driving unit receives a local dimming value for each block from the local dimming map generator using SPI (Serial Peripheral Interface) communication. According to claim 13,
The BLU driving unit includes a plurality of driving units,
The display device of claim 1 , wherein the driving unit includes a control unit receiving a local dimming value for each block from the control unit and a plurality of driver ICs respectively outputting driving signals for controlling brightness of two or more blocks. According to claim 15,
wherein the control unit parallelly outputs the local dimming value for each block, which is input in serial, and transmits the output to each of the plurality of driver ICs. According to claim 15,
The driver IC supplies driving signals to the light source packages included in the n blocks using n channels.

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