KR100964468B1 - Display apparatus - Google Patents

Abstract

PURPOSE: A display device is provided to reduce a thickness of the display device by providing a light to a display panel using a backlight unit for a module type consisting of a plurality of light guide plates. CONSTITUTION: A plurality of light sources(13) is located on a substrate and emits a light. A light guide plate(15) is composed of a light incidence part(15b) and a light emitting part(15a). The light incidence part includes an incidence face incidence with coming the light from the light source to the side. The light emitting part emits the light incoming to an upper side. An adjacent optical assembly in a plurality of optical assemblies has an overlapped part.

Description

Display apparatus

The present invention relates to a display device, and more particularly, to a method of driving a backlight unit included in the display device.

As the information society develops, the demand for display devices is increasing in various forms, and in recent years, liquid crystal display devices (LCDs), plasma display panels (PDPs), electro luminescent displays (ELDs), and vacuum fluorescents (VFDs) have been developed. Various display devices such as displays have been studied and used.

Among them, the liquid crystal panel of the LCD includes a liquid crystal layer and a TFT substrate and a color filter substrate facing each other with the liquid crystal layer interposed therebetween, and have no self-luminous power to display an image using light provided from the backlight unit. can do.

An object of the present invention is to provide a method capable of efficiently driving a backlight unit included in a display device and a display device using the same.

According to an exemplary embodiment of the present invention, a display apparatus includes: a backlight unit which is divided into a plurality of blocks each including at least one light source and driven for each of the divided blocks; A display panel positioned above the backlight unit; A controller configured to output a local dimming value corresponding to brightness of each of the blocks of the backlight unit according to the image displayed on the display panel; And a BLU driver controlling brightness of each of the blocks of the backlight unit by using a block-specific local dimming value input from the controller, wherein the backlight unit comprises: a substrate; A plurality of light sources formed on the substrate to emit light with a predetermined direction angle; And a plurality of optical assemblies each having a plurality of light guide plates each having a light incident portion that emits light incident from the light source, and a light emitting portion that emits the incident light upward. At least a portion of two light guide plates adjacent to each other overlap each other, and the BLU driver receives a local dimming value for each block and outputs a plurality of driving signals, and the blocks of the backlight unit are divided into a plurality of scan groups. It is driven in divided group units.

In the display device according to another embodiment of the present invention, the BLU driving unit includes a plurality of driving units, and the driving unit includes a control unit that receives a local dimming value for each block from the control unit and the two or more blocks. A plurality of driver ICs for outputting a drive signal for controlling the brightness, respectively.

According to an embodiment of the present invention, by providing light to the display panel by using a modular backlight unit composed of a plurality of light guide plates, a partial driving method such as local dimming while reducing the thickness of the display device Using to improve the contrast (contrast) of the display image.

In addition, by sequentially driving the plurality of light sources included in the backlight unit in group units, deterioration of image quality such as a motion blur phenomenon may be reduced.

Hereinafter, with reference to the accompanying drawings as follows. Hereinafter, the embodiments may be modified in various forms, and the technical scope of the embodiments is not limited to the embodiments described below. The examples are provided to more fully illustrate those skilled in the art. Accordingly, the shape and size of elements in the drawings may be exaggerated for clarity.

1 is an exploded perspective view showing the overall configuration of a display device.

Referring to FIG. 1, the display apparatus 1 includes a display module 200, a front cover 300 and a back cover 400 surrounding the display module 200, and a display cover 200 with the front cover 300. And / or a fixing member 500 for fixing to the back cover 400.

One side of the fixing member 500 is fixed to the front cover 300 by a fastening member such as a screw, etc., and the other side supports the display module 200 with respect to the front cover 300 to display the front cover 300. Module 200 may be fixed.

In this embodiment, the fixing member 500 is described as being formed in a plate shape extending in one direction as an example, but the separate fixing member 500 is not provided, and the display module 200 is provided by the fastening member. It is also possible that the configuration fixed to the front cover 300 or the back cover 400 is possible.

2 is a cross-sectional view of an embodiment of a display module configuration, and illustrates a cross-sectional configuration of the display module 200 cut along the line A-A of FIG. 1.

Referring to FIG. 2, the display module 200 may form a display panel 210 on which an image is displayed, a backlight unit 100 that provides light to the display panel 210, and a lower exterior of the display module 200. A bottom cover 110, a panel supporter 240 supporting the display panel 210 from below, and a top cover 230 supporting the display panel 210 from above and forming an edge of the display module 200. .

The bottom cover 110 may be formed in a box shape having an upper surface open to accommodate the backlight unit 100.

One side of the bottom cover 110 may be fixed to one side of the top cover 230. For example, a fastening member such as a screw penetrates the side surface of the display module 200, that is, the side where the bottom cover 110 and the top cover 230 overlap each other, and thus the bottom cover 110 and the top cover 230 may be separated. Can be fixed

Although not shown in detail, the display panel 210 includes, for example, a lower substrate 211 and an upper substrate 212 bonded together to maintain a uniform cell gap facing each other, and a liquid crystal layer interposed between the two substrates. can do. A plurality of gate lines and a plurality of data lines intersecting the plurality of gate lines may be formed on the lower substrate 211, and a thin film transistor (TFT) may be formed at an intersection of the gate lines and the data lines. have.

Meanwhile, color filters may be formed on the upper substrate 212, but the structure of the display panel 210 is not limited thereto, and the display panel 210 may have various structures. For example, the lower substrate 211 may include not only a thin film transistor but also a color filter. In addition, the display panel 210 may be formed in various shapes according to a method of driving the liquid crystal layer.

In addition, a gate driving printed circuit board (PCB) for supplying a scan signal to a gate line and a data driving printed circuit board (PCB) for supplying a data signal to a data line are provided at an edge of the display panel 210. ) May be provided. A polarizing film (not shown) may be disposed on at least one of the top and bottom of the display panel 210.

An optical sheet 220 may be disposed between the display panel 210 and the backlight unit 100, and the optical sheet 220 may be removed, but is not limited thereto. The optical sheet 220 may include a diffusion sheet (not shown) or a prism sheet (not shown).

The diffusion sheet evenly spreads the light emitted from the light guide plate, and the diffused light may be focused onto the display panel by the prism sheet. Here, the prism sheet may be selectively configured using a horizontal or / and vertical prism sheet, one or more roughness reinforcing films, and the like. Type or number of optical sheets 220 may be added or deleted within the technical scope of the embodiment, but is not limited thereto.

Meanwhile, the backlight unit 100 may include a plurality of optical assemblies 10 forming a plurality of divided driving regions. In addition, the display panel 210 has a plurality of divided regions corresponding to the respective optical assemblies 10, and the optical assemblies 10 of the display panel 210 are configured according to gray peak values or color coordinate signals of the divided regions. You can adjust the brightness.

The shape or structure of the liquid crystal panel 210, the backlight unit 100, or the optical assembly 10 provided in the backlight unit 100 illustrated in FIG. 2 is an embodiment according to the present invention, and the present invention is not limited thereto. .

3 is a plan view illustrating a first embodiment of the configuration of the backlight unit 100 and briefly illustrates a configuration of the backlight unit 100 viewed from the front.

Referring to FIG. 3, the plurality of optical assemblies 10 included in the backlight unit 100 may be arranged in a matrix form with N and M (N, M being one or more natural numbers) in the x and y axis directions, respectively. Can be.

According to an embodiment of the present invention, the optical assemblies 10 may be disposed to overlap a predetermined area with each other. That is, the optical assembly 10 may define the first area A and the second area B on a plane, and the first area A may include the light source 13, the first part 15b, and the side cover. 20, and the second region B may emit light received from the first region to the front side. The first region A may be disposed under the second region B of the optical assembly 10 disposed nearby.

The plurality of optical assemblies 10 may be arranged such that the first regions A overlap each other and are not observed in a plane. However, the first regions A of the optical assemblies 10 disposed at one edge of the backlight unit 100 may be exposed on a plane without overlapping. The second regions B may be provided in close proximity to the front / rear boundary and the left / right boundary.

Each optical assembly 10 is driven in an edge type backlight method, and each optical assembly 10 again acts as a light source to form a backlight unit by arranging a plurality of optical assemblies 10 in a direct type backlight mode. can do. Therefore, the problem of the light emitting diodes being observed as a hot spot on the screen can be solved, and the thickness of the light guide plate can be reduced and the number of optical films can be reduced, thereby making the backlight unit slim.

For example, in the backlight unit 100 of FIG. 1, nine optical assemblies M1 to M9 may be arranged in a 3 × 3 arrangement.

Each optical assembly 10 may be manufactured as an independent assembly, and may be disposed in close proximity to form a modular backlight unit. Such a modular backlight unit may provide light to the display panel as a backlight means.

The backlight unit 100 according to the embodiment may be driven in a full driving manner or a partial driving scheme such as local dimming or impulsive. The driving method of the light emitting diode 11 may be variously changed according to a circuit design, but is not limited thereto. As a result, the color contrast ratio is increased and the image of the bright and dark portions on the screen can be clearly expressed, thereby improving image quality.

That is, the backlight unit 100 may be divided into a plurality of blocks and driven for each of the divided blocks, and the black portion of the image may be connected to the luminance of each of the divided blocks by the luminance of the image signal. Reduced and bright parts can increase the brightness, thereby improving the contrast ratio and sharpness.

For example, when the backlight unit 100 is driven by a local dimming method, the display panel 210 may have a plurality of divided regions corresponding to each of the blocks of the backlight unit 100, and the display panel 210 The brightness of the light emitted from each of the blocks of the backlight unit 100 may be adjusted according to a luminance level of each of the divided regions of, for example, a peak value of a gray level or a color coordinate signal.

More specifically, only some of the optical assemblies included in the backlight unit 100, for example, the optical assembly M5 may be driven independently to emit light.

The backlight unit 100 according to the embodiment reduces the power consumption by applying a partial driving method, thereby reducing the cost.

In addition, the backlight unit 100 according to the embodiment may simplify the process of manufacturing the backlight unit 100 by assembling the optical assemblies 10 and may improve productivity by minimizing a loss that may occur during the assembly process. have. In addition, it is possible to reduce the occurrence of defects due to the light guide plate scratch, etc. that may occur in the assembly process of the backlight unit 100, and to improve the optical mura, thereby improving process reliability and improving quality.

The backlight unit 100 according to the embodiment has an effect that can be applied to backlight units of various sizes by standardizing the optical assembly 10 to mass production.

When a failure occurs in any one of the optical assemblies 10 of the backlight unit 100 according to the embodiment, the replacement operation is easy because only the optical assembly in which the failure occurs is replaced, instead of replacing the entire backlight unit 100. The cost of replacing parts is reduced.

The optical assembly 10 and the backlight unit 100 having the same according to the embodiment have a strong and durable effect against impact or environmental changes from the outside.

Since the optical assemblies 10 of the backlight unit 100 according to the exemplary embodiment are arranged with a part of the adjacent optical assemblies 10 overlapping each other, the generation of bright or dark lines at the boundary of the optical assemblies 10 and the uniformity of light are ensured. Has the possible effect.

The backlight unit 100 according to the embodiment can be easily applied to a large display panel. In addition, the embodiment has an advantageous effect in slimming the backlight unit and the display module.

In FIG. 3, the light source and the light guide plate constitute one optical assembly 10 and the plurality of optical assemblies 10 constitute the backlight unit 100 as an example, but the embodiment according to the present invention has been described. It is not limited.

According to the exemplary embodiment of the present invention, the backlight unit 100 may be composed of a plurality of optical assemblies 10, and each of the optical assemblies 10 may be driven by being divided into two or more blocks.

That is, the plurality of light sources included in one optical assembly 10 may be divided into a plurality of blocks, and may be driven for each of the divided blocks. For example, the plurality of light sources included in the optical assembly 10 M3 may be divided into a plurality of blocks, and may be driven in units of the divided blocks.

The block is a basic unit to which driving power for emitting light is emitted from the backlight unit 100, more specifically, the light sources included in the backlight unit 100, that is, the light sources included in one block are turned on at the same time. on or off, and may emit light of the same brightness when turned on. In addition, light sources included in different blocks of the backlight unit 100 may be supplied with different driving powers to emit light having different luminance.

4 is a block diagram illustrating a configuration of a display apparatus according to a first embodiment of the present invention. The illustrated display apparatus includes a controller 600, a BLU driver 610, a panel driver 620, and a backlight unit 100. And a display panel 210. Meanwhile, descriptions of the same elements as those described with reference to FIGS. 1 through 3 among the configurations of the display device illustrated in FIG. 4 will be omitted below.

Referring to FIG. 4, an image may be displayed at 60, 120, or 240 frames per second on the display panel 210. As the number of frames per second increases, the scan period T of the frame is shortened.

The panel driver 620 receives various control signals and image signals from the controller 600, generates a driving signal for driving the display panel 210, and supplies the driving signal to the display panel 210. For example, the panel driver 620 may include a gate driver (not shown) connected to the gate line of the display panel 210, a data driver (not shown), a timing controller (not shown) for controlling them, and the like. have.

The controller 600 controls the local dimming value according to the image signal to control the luminance of the light sources included in the backlight unit 100 and more specifically, the backlight unit 100 in response to the image signal. Can be printed as

In addition, the controller 600 may provide the BLU driver 610 with information about a scan period T in which one frame is displayed on the display panel 210, for example, a vertical synchronization signal Vsync.

The BLU driver 610 drives the light sources included in the backlight unit 100 according to the input scan period T so that the light is emitted from the light sources in synchronization with the display of the image on the display panel 210. can do.

Meanwhile, the light sources included in the backlight unit 100 may each include a plurality of point light sources, for example, light emitting diodes (LEDs), and the plurality of point light sources included in one block may be turned on at the same time. Or may be turned off.

Meanwhile, according to the exemplary embodiment of the present invention, by the dividing driving method such as local dimming, the plurality of light sources included in the backlight unit 100 are divided into a plurality of blocks, and each of the divided blocks The luminance of the light sources belonging to each block may be adjusted according to the luminance level of the area of the display panel 210 corresponding to the gray level peak value or the color coordinate signal.

For example, when the image is displayed in the first area of the display panel 210 and the image is not displayed in the second area, that is, displayed in black, the BLU driver 610 may display the image in the divided blocks. The light source included in the backlight unit 100, more specifically, the backlight unit 100 so that light sources belonging to the block corresponding to the second region emit light having a lower luminance than light sources belonging to the block corresponding to the first region. Can control them.

Meanwhile, the light sources belonging to the block of the backlight unit 100 corresponding to the second area in which the image is not displayed on the display screen of the display panel 210 and are displayed in black may be turned off. The power consumption of the display device can be further reduced.

That is, the controller 600 may adjust the local dimming value corresponding to the brightness of each of the blocks of the backlight unit 100 according to the luminance level of the input image signal, for example, the luminance level of the entire image or the luminance level of the specific region. A block-specific local dimming value may be generated and output to the BLU driver 610, and the BLU driver 610 may control the brightness of each of the blocks of the backlight unit 100 using the input block-specific local dimming value. .

Hereinafter, a driving method of a display apparatus according to an exemplary embodiment of the present invention will be described in detail with reference to FIGS. 5 to 10.

FIG. 5 is a block diagram illustrating a configuration of a display apparatus according to a second embodiment of the present invention, and descriptions of the same elements as those described with reference to FIGS. 1 to 4 are omitted below. Let's do it.

Referring to FIG. 5, a display apparatus according to an exemplary embodiment of the present invention receives an RGB image signal and determines the image by an image analyzer 601 and an image analyzer 601 to determine a luminance level of the entire or partial region of the image. The brightness determining unit 602 for determining the brightness of the light source corresponding to the brightness level, for example, the LED, and the BLU driver 610 for driving the backlight unit 100 according to the brightness level determined by the brightness determining unit 602. It may include.

In addition, the display device may be compensated by the pixel compensator 603 and the pixel compensator 603 that change the luminance level of the RGB image signal by reflecting the luminance level of the image analyzed by the image analyzer 601. The panel driver 620 may output a driving signal to the display panel 210 to output an image according to the R'G'B 'signal.

The image analyzer 601 divides an image area into a plurality of input RGB image signals, and determines a brightness of light sources belonging to a block of the backlight unit 100 corresponding to each area. ) Provides information about the luminance level of the image.

For example, the information on the luminance level of the image provided from the image analyzer 601 to the brightness determiner 602 may include an average luminance level (ABL) of a region corresponding to a block for which brightness is to be determined. ) As well as an average luminance level (APL) of another region adjacent to or an entire region of the image.

That is, the image analyzer 601 divides an image of one frame into a plurality of regions, and provides information on the average luminance level of the divided first region as well as the average luminance level of the other region adjacent to the first region. It may be provided to the brightness determining unit 602. In addition, the image analyzer 601 may provide corresponding information so that the brightness determiner 602 may use information on an average luminance level of the entire image when the brightness determiner 602 intends to determine the brightness of a specific block of the backlight unit 100. .

According to an embodiment of the present invention, a look-up table for determining the brightness of a specific block of the backlight unit 100 needs to be provided according to the average brightness level of all or a part of the measured image, and the brightness is determined. The unit 602 may read out and output the brightness of the light source corresponding to the average luminance level measured by the image analyzer 601 from the look-up table.

FIG. 6 is a graph illustrating a first embodiment of a method of determining a brightness of a light source according to an average brightness level of an image, wherein the x-axis is an average brightness level ABL of a divided area of the display panel 210. The y-axis represents the brightness of the block of the backlight unit 100 corresponding to the divided region, and the z-axis represents the average luminance level APL of the entire region.

Referring to FIG. 6, when the average luminance level of the entire image is less than the 'A' value, the brightness of the corresponding block of the backlight unit 100 is determined according to the first graph 3A, and the average luminance level of the entire image is' The brightness of the block of the backlight unit 100 is determined according to the second graph 3B when the A value is greater than or equal to the 'B' value, and when the average brightness level of the entire image is greater than or equal to the 'B' value, the third graph 3C As a result, the brightness of the block of the backlight unit 100 may be determined.

For example, when the average luminance level of the entire image is greater than or equal to the preset 'B' value, since the entire image should be expressed in bright gray levels, the brightness of the corresponding block of the backlight unit 100 using the third graph 3C is increased. Can be determined. In this case, since the image to be displayed on the display panel 210 is overall brightness, the phenomenon that the screen is dark while maximizing the local dimming effect of the backlight unit 100 is not a big problem.

According to another expression, when the image is to be expressed with a bright gradation as a whole, the larger 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 brightness of the corresponding block may be determined to be low. For reference, the LED brightness graph for the average brightness level for each partition is shown as a graph having a single slope.

On the other hand, when the image is to be represented with a dark gradation as a whole, that is, when the average luminance level of the entire image is less than the 'A' value, local dimming is performed only on the divided region having an average luminance level smaller than the preset luminance value. Can be.

That is, the proposed look-up table may allow local dimming in which the brightness of the light source is changed only to the divided region having an average luminance level smaller than the predetermined luminance value. This is because, when the image is entirely dark, if the brightness of the light source is determined according to a local dimming graph such as the third graph 3C, the brightness of the image is 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 the average luminance level of the predetermined brightness or more.

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 measured divided region is greater than the preset value, the brightness change of the light source is small and divided. When the average luminance level of the region is smaller than the preset value, the change in brightness of the light source is large. That is, the local dimming value corresponding to the light source may be reduced for the divided regions having bright gray levels, and the local dimming value corresponding to the light source may be relatively large for the divided regions having lower gray levels.

The graph showing the brightness of the light source for each average brightness level according to the look-up table is stored for the case where the average brightness level of the entire image is MAX and the average brightness level of the entire image is MIN. In addition, the table corresponding to the average luminance level of the entire measured image may be determined between the maximum (MAX) and the minimum (MIN) graph of the average luminance level.

Referring to FIG. 7, a graph 4C applied when the average luminance level APL of the entire image is maximum (MAX) and a graph 4A applied when the minimum (MIN) is applied are illustrated. That is, when the average brightness level of the entire image is the maximum, the image brightness is the maximum, so even if local dimming is performed on each divided region, color reproduction does not fall and power consumption due to driving of the backlight unit 100 may be considerably reduced. Can be.

When the average luminance level of the entire image is minimum, the image brightness is minimal. In this case, if local dimming is performed on the entire image, color reproducibility of the image is rather impaired. Therefore, in this case, when the average luminance level of the divided region is smaller than the preset value 4AA, local dimming is performed on the divided region, thereby preventing the color reproducibility from dropping significantly. It is possible to reduce the power consumption.

When the average luminance level of the entire image is not the maximum or the minimum, the look-up table (graph) to be applied may be generated by interpolating the graphs 4A and 4C. That is, the brightness determiner 602 may generate a new graph located in the area formed by the 4A and 4C graphs by using the look-up tables at the maximum and the minimum of the average luminance level of the entire image. .

According to another embodiment of the present invention, compensation for an image signal provided to the display panel 210, for example, an RGB signal, may be performed.

That is, when local dimming is performed on the backlight unit 100 as described above, there may be an area (or pixel) in which the color should be expressed in each of the divided areas of the display panel 100. In this case, gain may be applied to the RGB signal provided to the panel driver 620 according to the luminance level of the entire image, thereby reducing the incomplete reproduction of colors according to local dimming.

For example, when local dimming is performed on a specific area in an image, even if the average luminance level of the corresponding divided area is low, there may be a character or an image to be displayed in the divided area even if the degree of local dimming is large. That is, when the total APL is low, since the local dimming is large and the entire image appears dark, even the above characters or images to be expressed may be darkly expressed.

In this case, the power consumption reduction effect due to local dimming may be maintained, but color reproduction of the character or image may be made possible by improving the luminance level of the RGB signal provided to the display panel 210.

The pixel compensator 603 may compensate an image signal by multiplying the luminance level of an input RGB signal by a compensation value α, and for example, the average luminance level of the entire image measured by the image analyzer 601. The compensation value α can be calculated using.

8 is a graph illustrating an embodiment of a method of determining a compensation value α of an image signal according to an average luminance level of an image.

Referring to FIG. 8, when the screen is dark, a relatively large compensation can be performed, and in the case of a bright image, the compensation value α can be made smaller to reduce the saturation frequency of the RGB value, thereby providing more natural pixel compensation. This can be made possible.

The x-axis of the graph illustrated in FIG. 8 represents an average luminance level of the entire image measured by the image analyzer 601, and the y-axis represents a compensation value α for compensating the pixel of the RGB signal corresponding thereto.

That is, when local dimming is not applied or the local dimming value is less than or equal to a preset reference value, for example, 5 A or less, the compensation value α for compensating the pixel is set to 1 and the local dimming value is close to the maximum value MAX. As the value increases, the compensation value α may be increased to 1 or more. Therefore, it is possible to compensate the pixels as much as the image actually shown for the character or image is darkened by local dimming.

Meanwhile, the compensated character or image may mean a region in which the gain of the RGB image signal is greater than or equal to a preset specific value.

According to another embodiment of the present invention, the control unit 600 is a filtering unit for correcting the brightness level determined by the brightness determining unit 602 in order to prevent a sudden change in the brightness of the light source, for example, the LED ( Not shown) may be further included.

FIG. 9 illustrates a configuration of the BLU driver included in the display device. A description of the same elements as those described with reference to FIGS. 3 to 8 of the illustrated operation of the BLU driver 610 will be omitted below.

Referring to FIG. 9, the BLU driver 610 may indicate brightness of each of the divided blocks of the backlight unit 100 from the brightness determiner 602 included in the controller 600, more specifically, the controller 600. The controller may receive a local dimming value for each block, and output a plurality of driving signals, for example, first to m-th driving signals using the input local dimming value for each block.

Meanwhile, each of the plurality of driving signals output from the BLU driver 610 may control brightness of two or more blocks among the divided blocks of the backlight unit 100.

That is, the BLU driver 610 generates the first driving signal for controlling the brightness of n blocks, for example, the first to nth blocks, among the blocks of the backlight unit 100 to generate the first to nth. The first driving signal may be supplied to light sources belonging to the blocks, and the first driving signal is generated by using local dimming values corresponding to the first to n-th blocks among block local dimming values input from the controller 600. can do.

According to an embodiment of the present invention, the control unit 600 and the BLU driver 610 may transmit and receive signals using SPI (Serial Peripheral Interface) communication, that is, the BLU driver 610 may use the SPI communication. The controller 600 may receive a local dimming value for each block.

Referring to FIG. 10, the BLU driver 610 may include a plurality of driving units 611 and 615, and the driving units 611 and 615 may be MCUs 612 and 616 and a plurality of drivers, respectively. ICs 613 and 617 may be included.

For example, the first driving unit 611 may include an MCU 612 and a plurality of driver ICs 613, and the MCU 612 may be provided in the controller 600, more specifically, in the controller 600. The local dimming value for each block is serially input from the brightness determining unit 602 and output in parallel to transfer local dimming values of blocks corresponding to each of the plurality of driver ICs 613.

Meanwhile, each of the plurality of driver ICs 613 may control the brightness of n blocks among the divided blocks of the backlight unit 100, and for this purpose, control the brightness of the n blocks by using n channels. A drive signal can be output.

For example, the first driving unit 611 may include four driver ICs 613, and each of the four driver ICs 613 may output a driving signal using 16 channels to belong to 16 blocks. The brightness of the light sources can be controlled. Accordingly, the first driving unit 611 may control the brightness of 4 × 16, that is, 64 blocks among the divided blocks of the backlight unit 100.

In addition, the second driving unit 615 may include an MCU 616 and a plurality of driver ICs 617, and the MCU 616 may determine brightness of the controller 600, and more specifically, the controller 600. The local dimming value of each block may be input from the unit 602 in serial and output in parallel to transfer local dimming values of blocks corresponding to each of the plurality of driver ICs 617.

Meanwhile, each of the plurality of driver ICs 617 may control the brightness of n blocks among the divided blocks of the backlight unit 100, and for this purpose, control the brightness of the n blocks by using n channels. A drive signal can be output.

Since the configuration of the BLU driver 610 shown in FIG. 10 is only an embodiment according to the present invention, the display device according to the present invention is not limited to the configuration shown in FIG. 10. That is, the BLU driver 610 may include three or more driving units, and the number of blocks of the backlight unit 100, in which each driving unit controls brightness, may be changed.

According to an exemplary embodiment of the present invention, the backlight unit 100 may be divided into a plurality of scan groups, and may be sequentially driven in group units. For this purpose, the BLU driver 610 receives a local dimming value for each block from the controller 600 and drives the light sources provided in the backlight unit 100, more specifically, the backlight unit 100, and thus the backlight unit 100. The divided blocks of) may be controlled to be sequentially driven in one or more group units.

Accordingly, when viewing a scene in which a specific object moves in the video, the phenomenon that the image is aggregated while the viewer's eyes follow the moving object may be reduced, that is, motion blur.

FIG. 11 is a plan view illustrating a configuration of a backlight unit according to a second embodiment of the present invention. Description of the same configuration as that described with reference to FIGS. 1 to 10 of the configuration of the backlight unit 100 illustrated in FIG. Will be omitted below.

Referring to FIG. 11, the backlight unit 100 may be divided into a plurality of blocks 101 to be driven for each of the divided blocks, and the plurality of divided blocks 101 may include at least one convex. The scan groups may be divided into a plurality of scan groups SG1, SG2, and SG3. In addition, the plurality of scan groups SG1, SG2, and SG3 may be sequentially driven.

Meanwhile, the scan groups may include one or more local dimming blocks. For example, the first scan group SG1 may include a plurality of local dimming blocks.

The BLU driver 610 inputs, for each of the scan groups SG1, SG2, and SG3, a local dimming value of blocks belonging to the scan group and information about a time when the scan group is scanned, from the controller 600. The scan groups SG1, SG2, and SG3 may be sequentially driven with a predetermined time difference according to the input local dimming value.

Since the configuration of the backlight unit 100 illustrated in FIG. 11 is only one embodiment according to the present invention, the present invention is not limited thereto. That is, the number of scan groups in which the backlight unit 100 is sequentially driven may be 4 or more, and as illustrated in FIG. 11, at least two scan groups, for example, a first scan group SG1 and a second scan group ( The number of blocks belonging to each of SG2) may be different from each other, or the number of blocks belonging to each of all scan groups may be the same.

Also, the scan group may be composed of various types of blocks instead of radial blocks. For example, it may also be composed of a block of 'b' or 'b' form. In addition, since each scan group may be composed of a plurality of local dimming blocks, local dimming control may be possible for each scan group.

12, a plurality of scan groups SG1, SG2, and SG3 of the backlight unit 100 may be sequentially driven during a period between two vertical sync signals Vsync, that is, a period corresponding to one frame. Can be.

That is, as shown in FIG. 12, light sources belonging to blocks of each of the plurality of scan groups SG1, SG2, and SG3 may be sequentially turned on.

More specifically, the one or more MCUs 612 and 616 included in the BLU driver 610 are connected to the plurality of driver ICs 613 and 617, respectively, by using information on a scan time received from the controller 600. The local dimming value input from the controller 600 may be sequentially output.

13 and 14 illustrate embodiments of a method of scanning driving blocks of a backlight unit in group units.

Referring to FIG. 13, the BLU driver 610 may receive information on a scan period T corresponding to one frame from the controller 600, and the BLU driver 610 may receive information on the scan period T. Accordingly, blocks of the backlight unit 100, more specifically, light sources may be sequentially scanned in groups during the frame period between two consecutive vertical sync signals Vsync.

For example, the controller 600 may include a first group data signal Data 1 representing a local dimming value corresponding to brightness of each of the light sources included in the blocks of the first scan group SG1, and the first scan group. The first group control signal delay 1 indicating the delay time until the light sources of SG1 are scanned according to the data signal Data 1 may be supplied to the BLU driver 610.

Thereafter, the controller 600 may include a second group data signal Data 2 representing a local dimming value corresponding to the brightness of each of the light sources included in the blocks of the second scan group SG2, and the second scan group ( The second group control signal delay 2 representing a delay time until a time point at which the light sources of SG2 are scanned according to the data signal Data 2 may be supplied to the BLU driver 610.

Finally, the controller 600 may include a third group data signal Data 3 representing a local dimming value corresponding to the brightness of each of the light sources included in the blocks of the third scan group SG3, and the third scan group ( A third group control signal delay 3 representing a delay time until a light source of SG3 is scanned according to the data signal Data 3 may be supplied to the BLU driver 610.

As illustrated in FIG. 13, the control unit 600 controls the data signals data 1, 2, and the like for each of a plurality of scan groups, for example, for each of the first, second, and third scan groups SG1, SG2, and SG3. 3) and the group control signals delay 1, 2, and 3 are sequentially supplied, the plurality of blocks included in the backlight unit 100, more specifically, light sources may be scan-driven in group units.

Referring to FIG. 14, the control unit 600 may supply scan start signals STH 1, 2, and 3 for each of the scan groups of the backlight unit 100 to indicate when the light sources of the group are scanned for each scan group. Can be.

That is, the controller 600 may include a first group data signal Data 1 representing brightness of light sources belonging to the first scan group SG1 and a second group data signal Data representing brightness of light sources of the second scan group SG2. 2) and the third group data signal Data 3 representing the brightness of the third scan group SG3 light sources may be sequentially supplied through the data line data.

In addition, the controller 600 supplies a first group scan start signal STH 1 to the BLU driver 610 in synchronization with a scan start time of the first scan group SG1, and the second scan group SG2. The second group scan start signal STH 2 is supplied to the BLU eastern part 610 in synchronization with the scan start time of the third group scan start signal (STH 2) and in synchronization with the scan start time of the third scan group SG3. STH 3) may be supplied to the BLU driver 610.

For example, the controller 600 may generate the scan start signals STH 1, 2, and 3 as shown in FIG. 14 by delaying the vertical sync signal Vsync for each scan group by a predetermined time. The delay time of the vertical sync signal Vsync for each scan group may be set according to the scan start time of each group.

15 is a cross-sectional view illustrating a configuration of a backlight unit according to an exemplary embodiment of the present invention, and FIG. 16 is a perspective view of FIG. 15. 17 to 19 are perspective views illustrating respective parts of the optical assembly according to the embodiment.

15 to 17, the optical assembly 10 according to the embodiment includes a light source 13, a light guide plate 15, and a reflective member 17, and a side for fixing the light source 13 and the light guide plate 15. Cover 20. The side cover 20 provides a fixed position with respect to the bottom cover 110, and includes a first side cover 21 and a second side cover 22.

The light guide plate 15 includes a first part 15b and a second part 15a. In addition, the second part 15a may be formed of four side surfaces, a top surface on which the surface light source is generated, and a bottom surface facing the top surface.

The first part 15b may protrude in a horizontal direction along a lower portion of one side of the side surfaces of the second part 15a. Here, the first part 15b may be referred to as a light incident part through which light is incident from the light source 13, and the second part 15a emits light upward and substantially provides light to the display panel 210. It may be referred to as a light emitting unit.

As shown in FIG. 15, at least a part of the light emitting part 15a of one of the two light guide plates adjacent to each other may be disposed above the light receiving part 15b of the other light guide plate.

A scattering pattern (not shown) may be formed on the top or bottom surface of the light guide plate 15. The scattering pattern has a predetermined pattern and diffuses the incident light to improve light uniformity on the entire surface of the light guide plate 15.

As shown in FIG. 15, the lower part of the light guide plate 15 may be formed to be inclined at a predetermined angle from one side adjacent to the first part 15b to the other end opposite to the first part 15b. The thickness of the two parts 15a may become thinner and thinner.

The lower surface of the light guide plate 15 may be provided with a reflective member 17. The reflective member 17 allows the light incident to the side through the first part 15b to be guided inside the light guide plate 15 to be reflected by the reflective member 17 and then emitted to the upper surface. In addition, the reflective member 17 may serve to block interference by light generated from another optical assembly 10 disposed in an overlapping manner.

The first part 15b may have a structure protruding along the lower side of the light guide plate 15, and may include a protrusion 30 protruding from the upper surface to a predetermined height a.

The protrusions 30 may be formed in at least two locations in the x-axis direction on the upper surface of the first part 15b. The protrusion 30 may have various shapes, for example, a shape similar to a cuboid. The protrusion 30 can be prevented from shaking of the light guide plate 15 along the x-axis and the y-axis by engaging the first side cover 21.

On the other hand, some of the corners (30a) of the corners of the projection 30 is formed to be round to prevent the crack (crack) generated on the projection by the impact applied to the projection 30 by the movement of the light guide plate (15).

The projection 30 may have a height a of 0.3 to 0.6 mm from the upper surface of the first part 15b, the width b on the x axis is 2 to 5 mm, and the width c on the y axis is It may be 1-3mm.

In addition, the protrusion 30 may be disposed between adjacent light emitting diodes 11 and may be formed to be close to the light incident surface 16 on the upper surface of the first part 15b. Therefore, it is possible to prevent the light generated from the light emitting diodes 11 from generating optical interference due to the projection 30 integrally formed with the light guide plate 15.

The positional relationship between the light emitting diodes 11, the protrusions 30 formed on the upper surface of the first part 15b of the light guide plate 15, and the size of the protrusions 30 are not limited thereto. It can have a variety of positional relationships.

The light guide plate 15 may be made of a transparent material, and may include, for example, one of an acrylic resin series such as polymethyl metaacrylate (PMMA), polyethylene terephthlate (PET), polycarbonate (PC), and polyethylene naphthalate (PEN) resin. have. The light guide plate 15 may be formed by an extrusion molding method.

15 and 18, the light source 13 may include at least one light emitting diode 11 and a module substrate 12 on which the light emitting diode 11 is mounted.

The light emitting diodes 11 may be arranged on the module substrate 12 in the x-axis direction and disposed to be adjacent to the light incident surface 16 of the first part 15b.

The module substrate 12 is made of a metal core PCB, FR-4 PCB, a general PCB, a flexible substrate, etc., can be variously changed within the technical scope of the embodiment.

A thermal pad (not shown) may be disposed under the module substrate 12. The heat dissipation member may be formed between the module substrate 12 and the second side cover 22.

The light emitting diode 11 may be a side light emitting type, and the light emitting diode 11 may be a colored LED or a white LED emitting at least one of colors such as red, blue, and green. In addition, the colored LED may include at least one of a red LED, a blue LED, and a green LED, and the arrangement and emission light of the light emitting diode 11 may be changed within the technical scope of the embodiment.

Light generated by the light emitting diodes 11 is incident sideways to the first part 15b. Light incident from the light emitting diodes 11 may be mixed in the light guide plate 15 including the first part 15b.

Light incident from the light emitting diodes 11 is guided in the first part 15b and is incident to the second part 15a. Light incident on the second part 15a is reflected by the reflecting member 17 on the lower surface and emitted to the upper surface. In this case, since light is scattered and diffused by the scattering pattern formed on the lower surface of the light guide plate 15, light uniformity may be improved.

The light emitting diodes 11 may be disposed on the module substrate 12 at predetermined intervals. The light emitting diode 11 may be disposed in an oblique direction with respect to the protrusion 30 in order to minimize the optical effect of the protrusion 30 formed on the light guide plate 15. Thus, the spacing of the light emitting diodes 11 around the protrusion 30 may be wider than the spacing of other light emitting diodes 11.

The light emitting diodes 11 may be provided to secure a space for coupling the first side cover 21 and the second side cover 22 and to minimize an optical effect that may be generated by the light guide plate 15 being pressed by the coupling force. The spacing of some of the light emitting diodes 11 may be wider than the spacing of other light emitting diodes 11.

For example, if the first spacing d of the adjacent light emitting diodes 11 is about 10 mm, the second spacing e of the light emitting diodes 11 near the position where a space for coupling is provided may be about 13 mm. .

Light generated by the light emitting diodes 11 may be mixed in the light guide plate 15 including the first part 15b and uniformly provided to the second part 15a.

15 and 19, the side cover 20 is formed to surround the light source 13 and a part of the light guide plate 15. For example, the side cover 20 may include a first side cover 21 disposed above the light source 13 and the first part 15b and a second side cover disposed below the first part 15b. 22). Meanwhile, the side cover 20 may be made of plastic or metal material.

The first side cover 21 is formed to face the upper surface of the first part 15b. The first side cover 21 may be bent in a downward direction (z-axis line) to face the light incident surface 16 on the upper surface of the first part 15b.

The second side cover 22 is formed to face the lower surface of the first part 15b. The second side cover 22 may be bent in an upward direction (z-axis line) to face the light incident surface 16 on the lower surface of the first part 15b. A portion 22a of the second side cover 22 may be formed to be inclined along the lower surface of the light guide plate 15, that is, the inclined surface, and the light source 13 may be accommodated in the second side cover 22.

The first side cover 21 and the second side cover 22 are fastened to each other by the first fixing member 51 so that the light source 13 and the light guide plate 15 are not shaken by an external impact, in particular in the z-axis direction. Make sure that shaking is prevented.

The second side cover 22 may support the inclined surface of the light guide plate 15 to maintain the alignment of the light guide plate 15 and the light source 13 firmly and protect from external shock.

In the first side cover 21, a first hole 41 may be formed at a position corresponding to the protrusion 30 of the first part 15b, and the first hole 41 may be caught by the protrusion 30. It may be formed larger than the projection (30). Meanwhile, the circumference of the first hole 41 may be spaced apart from a predetermined edge of the fitted protrusion 30 by the predetermined space, and the space is expanded by the light guide plate 15 due to a change in external environment, for example, a sudden temperature rise. It may be a margin for preventing deformation of the light guide plate 15. In this case, another portion of the protrusion 30 may contact the circumference of the first hole 41 to strengthen the fixing force.

At least one second hole 42 may be further formed in the first side cover 21. At least one third hole 43 may be formed in the second side cover 21 at a position corresponding to the second hole 42.

The second and third holes 42 and 43 are disposed in a straight line in the z-axis direction, and the first fixing member 51 is inserted to firmly fix the first side cover 21 and the second side cover 22. can do. In order to secure a fixing force, at least two pairs of second and third holes 42 and 43 may be formed in one optical assembly 10. The second hole 42 and the third hole 43 may be formed at any position of the first side cover 21 and the second side cover 22, respectively.

In the first side cover 21, the second hole 42 may be disposed in a straight line with the first hole 41 in the y-axis direction. In this case, the coupling force between the light guide plate 15 and the first side cover 21 by the protrusion 30 of the first hole 41 and the light guide plate 15, the second and third holes 42 and 43, and the first fixing The first side cover 21 and the second side cover 22 may be more firmly fixed by the coupling force between the first side cover 21 and the second side cover 22 by the member 51. Of course, the positions of the holes and the protrusions are not limited thereto, and any position may be used as long as the position of the holes and the protrusions may provide a coupling force between the light guide plate 15 and the side cover 20.

That is, the second hole and the third hole will be formed in the side portion overlapping the first side cover 21 and the second side cover 22, respectively, it is also possible to be configured that the fixing member is inserted in the y-axis direction.

Meanwhile, a fourth hole through which the second fixing member 52 (see FIG. 10) through which the optical assembly 10 is fixed to the bottom cover 110 passes through the first side cover 21 and the second side cover 22. 44 and the fifth hole 45 may be further formed.

The remaining portion of the optical assembly 10 except for the second part 15a of the light guide plate 15 is a first area that substantially does not provide light to the display panel, and includes the first hole 41 and the second hole 42. And the width of the first region may be further reduced by the arrangement relationship of the third holes 43.

For example, the case where the second hole 42 and the third hole 43 are disposed between the light emitting diodes 11 may reduce the width of the first area than the case where the second hole 42 and the third hole 43 are disposed behind the light emitting diodes 11. Can be.

Here, the shape of the first hole 41, the second hole 42, and the third hole 43 formed in the side cover 20 of the optical assembly 10 may be various, and is limited to the illustrated form. It is not.

The first fixing member 51 may be a screw or a fixing pin, but is not limited thereto. When the first fixing member 51 is a screw, peaks and valleys may be formed on the inner surfaces of the second and third holes 42 and 43 along the screw line. As a result, the first fixing member 51 is inserted into the second hole 42 and the third hole 43 and rotated to clamp and fix the light guide plate 15 and the light source 13 sandwiched therebetween.

In order to secure the pitch of the peaks formed on the inner surfaces of the second hole 42 and the third hole 43, the first and second side covers 21 and 22 may include the second hole 42 and the third hole 43. The thickness of the periphery may be thicker than other parts, or a separate member may be used.

The backlight unit 100 manufactured as described above may be accommodated in a box-shaped bottom cover having an upper surface opened.

The present invention has been described above with reference to preferred embodiments thereof, which are merely examples and are not intended to limit the present invention. Those skilled in the art to which the present invention pertains do not depart from the essential characteristics of the present invention. It will be appreciated that various modifications and applications are not possible that are not illustrated above. For example, each component shown in detail in the embodiment of the present invention may be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

1 is an exploded perspective view showing the configuration of a display device.

2 is a cross-sectional view illustrating an embodiment of a configuration of a display module.

3 is a plan view briefly illustrating a configuration of a backlight unit according to a first exemplary embodiment of the present invention.

4 is a block diagram schematically illustrating a configuration of a display apparatus according to a first embodiment of the present invention.

5 is a block diagram illustrating a configuration of a display apparatus according to a second exemplary embodiment of the present invention.

6 is a graph illustrating a first embodiment of a method of determining the brightness of a light source according to an average brightness level of an image.

7 is a graph illustrating a second embodiment of a method of determining the brightness of a light source according to an average brightness level of an image.

8 is a graph illustrating an embodiment of a method of determining a compensation value of an image signal according to an average luminance level of an image.

9 is a block diagram briefly illustrating a configuration of a BLU driver.

10 is a block diagram illustrating an embodiment of a configuration of a BLU driver.

11 is a plan view briefly illustrating a configuration of a backlight unit according to a second exemplary embodiment of the present invention.

12 to 14 are timing diagrams illustrating embodiments of a method of scanning driving blocks of a backlight unit in group units.

15 is a cross-sectional view illustrating a cross-sectional structure of a backlight unit according to an exemplary embodiment of the present invention.

16 to 19 are perspective views illustrating respective parts of the backlight unit illustrated in FIG. 15.

Claims (19)

A backlight unit which is divided into a plurality of blocks and is driven for each of the divided blocks, and includes a plurality of optical assemblies; A display panel positioned above the backlight unit; A controller configured to output a block-specific local dimming value corresponding to brightness of each block of the backlight unit according to the image displayed on the display panel; And It includes a BLU driver for controlling the brightness of the blocks of the backlight unit by using the local dimming value for each block, The optical assembly Board; A plurality of light sources positioned on the substrate and emitting light; And And a light guide plate including an incident surface including an incident surface on which light is laterally incident from the light source, and a light emitting plate configured to emit the incident light upward. At least a portion of two optical assemblies adjacent to each other of the plurality of optical assemblies overlap each other, The backlight unit includes a plurality of substrates separated to correspond to the plurality of optical assemblies, The BLU driving unit receives the local dimming value for each block and outputs a plurality of driving signals, and the blocks of the backlight unit are divided into a plurality of scan groups and driven in the divided group units. The method of claim 1, wherein the BLU drive unit And a display apparatus for receiving at least one local dimming value of at least one block belonging to the scan group and information on a time point at which the scan group is scanned. The method of claim 2, wherein the information on the scan time is And a delay time from when a vertical synchronization signal is input to when a scan group is scanned. The method of claim 2, wherein the information on the scan time is And a scan start signal indicating a time point at which the scan group is scanned. The method of claim 1, And at least two scan groups among the plurality of scan groups have different numbers of blocks belonging to the scan groups. The method of claim 1, And a plurality of driving signals output from the BLU driver to control brightness of at least two of the blocks of the backlight unit. The method of claim 1, The display panel is divided into a plurality of areas, The control unit And a brightness of a block of the backlight unit corresponding to the area according to brightness of each of the areas of the display panel. The method of claim 1, wherein the BLU drive unit A display device for receiving the local dimming value for each block from the controller using Serial Peripheral Interface (SPI) communication. The method of claim 1, wherein the light source And a light emitting surface intersecting the substrate. The method of claim 1, And at least a portion of the light emitting portion of the first light guide plate of two light guide plates respectively included in the two optical assemblies adjacent to each other, disposed above the light incident portion of the second light guide plate. The method of claim 1, And a light emitting part of the light guide plate that gradually decreases in thickness from one side adjacent to the light incident part to the other side. The optical assembly of claim 1, wherein the optical assembly Reflective members disposed under the light guide plates; And And a side cover to which the substrate, the plurality of light guide plates, and the reflective member are fixed. A backlight unit which is divided into a plurality of blocks and is driven for each of the divided blocks, and includes a plurality of optical assemblies; A display panel positioned above the backlight unit; A controller configured to output a block-specific local dimming value corresponding to brightness of each block of the backlight unit according to the image displayed on the display panel; And It includes a BLU driver for controlling the brightness of the blocks of the backlight unit by using the local dimming value for each block, The optical assembly A plurality of light sources; And And a light guide plate including an incident surface including an incident surface on which light is laterally incident from the light source; The backlight unit includes a plurality of substrates separated to correspond to the plurality of optical assemblies, The blocks of the backlight unit are driven by the divided group by dividing the light source into a plurality of scan groups. The BLU drive unit is configured to include a drive unit, The driving unit includes a control unit receiving a local dimming value for each block from the controller and a plurality of driver ICs respectively output driving signals for controlling brightness of the two or more blocks. The method of claim 13, wherein the control unit And a local dimming value for each block input in serial, in parallel, and transmitted to each of the plurality of driver ICs. The method of claim 13, wherein the driver IC A display device for supplying a driving signal to the light sources included in the n blocks using the n channels. The method of claim 13, wherein the BLU drive unit And a plurality of driving units. The method of claim 13, wherein the light source And a light emitting surface intersecting the substrate. A backlight unit which is divided into a plurality of blocks and is driven for each of the divided blocks, and includes a plurality of optical assemblies; A display panel positioned above the backlight unit; A controller configured to output a block-specific local dimming value corresponding to brightness of each block of the backlight unit according to the image displayed on the display panel; And It includes a BLU driver for controlling the brightness of the blocks of the backlight unit by using the local dimming value for each block, The optical assembly Board; A plurality of light sources positioned on the substrate and emitting light; And And a light guide plate including an incident surface including an incident surface on which light is laterally incident from the light source; The light guide plate includes a portion of which the thickness decreases from one side to the other side, The backlight unit includes a plurality of substrates separated to correspond to the plurality of optical assemblies, The BLU driving unit receives the local dimming value for each block and outputs a plurality of driving signals, and the blocks of the backlight unit are divided into a plurality of scan groups and driven in the divided group units. The method of claim 18, wherein the light source And a light emitting surface intersecting the substrate.

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