KR102352693B1 - Video wall device and driving method of the same - Google Patents

Abstract

The present invention relates to a video wall device and a driving method thereof, and the video wall device according to the present invention includes a plurality of display devices and a main control unit for outputting image signals to the plurality of display devices, and the main control unit includes each display device. an image average level calculator for calculating the average image level of images output from the display panel of and a Gaussian curve setting unit configured to set the luminance of the display panel to conform to the Gaussian curve, and a gain determining unit configured to determine a luminance gain of each display panel.
Accordingly, the difference in overall luminance of each display panel is reduced below the viewer's perception level, and thus the quality of the entire image of the video wall device may be improved. In addition, by increasing the gain of the luminance of the entire display panel, there is an effect of increasing the luminance of the entire video wall device.

Description

Video wall device and its driving method {VIDEO WALL DEVICE AND DRIVING METHOD OF THE SAME}

The present invention relates to a video wall device and a driving method thereof, and more particularly, by setting the luminance of a display panel provided in the video wall device to conform to a Gaussian curve to uniformly increase the luminance of the video wall device It relates to a video wall device and a driving method thereof.

As the information society develops, the demand for a display device for displaying an image is increasing in various forms, and in recent years, a liquid crystal display device, a plasma display panel, and an organic light emitting display device ( Various display devices such as Organic Light Emitting Display Device) are being used.

Although the screen size of display devices has continuously increased thanks to technological advances, there is a limit to realizing extra-large screens such as electronic boards and billboards.

Accordingly, a video wall device for connecting a plurality of display devices has been developed in order to realize an extra-large screen. A plurality of display devices provided in such a video wall device respectively display a plurality of divided images obtained by dividing one image.

Here, luminances of display panels of a plurality of display devices included in a video wall device are different from each other due to a plurality of different divided images. Accordingly, the luminance of the video wall device is not uniform as a whole, and the quality of the output image is deteriorated.

Therefore, in order to solve this problem, the luminance of the plurality of display panels is set as the minimum luminance value among the luminances of the display panels of the plurality of display devices included in the video wall device.

However, when the luminance of the plurality of display panels is set as the minimum luminance value, the luminance of the video wall device is reduced as a whole, thereby reducing the visibility of the output image.

That is, the video wall device has a problem in that the overall luminance of the video wall device is not uniform and deteriorated due to a plurality of display devices that output different images.

Accordingly, an object of the present invention is to provide a video wall device capable of uniformly increasing the luminance of a video wall device by setting the luminance of a display panel provided in the video wall device to conform to a Gaussian curve, and a method of driving the same will do

The problems of the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

In order to solve the above problems, a video wall device according to an embodiment of the present invention includes a plurality of display devices and a main controller for outputting image signals to the plurality of display devices, and the main controller is configured to control each display device. An image average level calculator for calculating the average image level of images output from the display panel, a peak luminance controller for controlling the peak luminance of each display panel based on the image average level, and each display based on the image average level and a Gaussian curve setting unit configured to set the luminance of the panel to conform to the Gaussian curve, and a gain determining unit configured to determine a luminance gain of each display panel.

In order to solve the above problems, a method of driving a video wall device according to an embodiment of the present invention includes an image average level calculation step of calculating an image average level of images output from each display panel, and based on the image average level Thus, the peak luminance control step of controlling the peak luminance of each display panel, the Gaussian curve setting step of setting the luminance of each display panel to conform to the Gaussian curve based on the image average level, and the luminance of each display panel and a gain determining step of determining a gain.

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

According to the present invention, even when there is a large difference in the image average level (APL) between the plurality of display panels, the difference in overall luminance between the plurality of display panels can be reduced. Accordingly, the difference in overall luminance of each display panel is reduced below the viewer's perception level, and thus the quality of the entire image of the video wall device may be improved.

In addition, the present invention has the effect of increasing the luminance of the entire video wall device by increasing the luminance gain of the entire display panel by comprehensively considering the region of interest, the complexity of the image, and the current consumption value of each display panel.

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

1 is a schematic block diagram illustrating a video wall apparatus according to an embodiment of the present invention.
2 is a schematic block diagram illustrating a plurality of display devices included in a video wall device according to an embodiment of the present invention.
3 is a circuit diagram illustrating driving of pixels disposed in a display device included in a video wall device according to an embodiment of the present invention.
4 is a schematic block diagram illustrating a main controller included in a video wall device according to an embodiment of the present invention.
5 is a graph for explaining an operation of a peak luminance controller included in a video wall device according to an embodiment of the present invention.
6 is a graph illustrating the luminance of a display panel provided in a video wall device according to an exemplary embodiment of the present invention.
7 is a schematic block diagram illustrating a gain determiner included in a video wall device according to an embodiment of the present invention.
8 is a diagram illustrating a plurality of display areas disposed on a display panel provided in a video wall device according to an embodiment of the present invention.
9 is a flowchart illustrating a method of driving a video wall device according to an embodiment of the present invention.
10 is a flowchart illustrating a gain determination step of a method of driving a video wall device according to an embodiment of the present invention.

Advantages and features of the present invention and methods of achieving them will become apparent 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 forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention belongs It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims.

In describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. When 'including', 'having', 'consisting', etc. mentioned in this specification are used, other parts may be added unless 'only' is used. When a component is expressed in the singular, cases including the plural are included unless otherwise explicitly stated.

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

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

Like reference numerals refer to like elements throughout.

Each feature of the various embodiments of the present invention may be partially or wholly combined or combined with each other, and as those skilled in the art will fully understand, technically various interlocking and driving are possible, and each embodiment may be implemented independently of each other, It may be possible to implement together in a related relationship.

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

1 is a schematic block diagram illustrating a video wall apparatus according to an embodiment of the present invention.

Referring to FIG. 1 , a video wall device 1000 according to an embodiment of the present invention includes a plurality of display devices 100 to 900 and a main controller 1010 . For example, in FIG. 1 , the video wall device 1000 is configured by arranging a plurality of display devices 100 to 900 in a 3×3 tile shape. However, although FIG. 3 shows that the video wall device 1000 is configured by arranging nine display devices 100 to 900 in a 3×3 tile shape, the number of display devices constituting one video wall device 1000 and There are no restrictions on the layout structure.

In addition, the main controller 1010 receives an input signal Input from an external host system and outputs an image signal VS to each of the plurality of display devices 100 to 900 . Here, the input signal Input is a signal for displaying one entire image output to the video wall device 1000 , and the image signal VS is a signal obtained by dividing one entire image by the plurality of display devices 100 to 900 . It is a signal for displaying a divided image. Accordingly, the plurality of display devices 100 to 900 individually receive the plurality of image signals VS and respectively output divided images. Accordingly, the divided images displayed on the display devices 100 to 900 of the video wall device 1000 are combined to realize the entire image.

2 is a schematic block diagram illustrating a plurality of display devices included in a video wall device according to an embodiment of the present invention.

Hereinafter, the first display device 100 among the plurality of display devices 100 to 900 included in the video wall device 1000 will be described as an example.

Referring to FIG. 2 , the first display device 100 includes a display panel 110 , a data driver 120 , a gate driver 130 , and a timing controller 140 .

In the display panel 110 , a plurality of gate lines GL1 to GLm and a plurality of data lines DL1 to DLn are intersected in a matrix form on a substrate made of glass or plastic. A plurality of pixels Px are defined at intersections of the plurality of gate lines GL1 to GLm and the data lines DL1 to DLn.

In addition, each pixel Px of the display panel 110 is provided with at least one thin film transistor. The gate electrode of the thin film transistor is connected to the gate line GL, and the source electrode is connected to the data line DL.

The first display device 100 may be an organic light emitting diode display. In this case, current is applied to the organic light emitting diodes (OLEDs of FIG. 3 ) disposed in the plurality of pixels Px, and excitons are generated by the combination of emitted electrons and holes. Then, the exciton emits light to realize the grayscale of the organic light emitting diode display. Details on this will be described later with reference to FIG. 3 .

As described above, the first display device 100 is not limited to an organic light emitting diode display, and may be a display device of various types, such as a liquid crystal display.

In addition, each pixel Px may include a plurality of sub-pixels, and each sub-pixel may implement light of a specific color. For example, the plurality of sub-pixels may include a red sub-pixel implementing red, a green sub-pixel implementing green, and a blue sub-pixel implementing blue, but is not limited thereto.

The timing controller 140 supplies various control signals DCS and GCS and image data RGB to the data driver 120 and the gate driver 130 to control the data driver 120 and the gate driver 130 . .

The timing controller 140 starts a scan according to the timing implemented in each frame based on the timing signal TS received from the main controller 1010 . In addition, the timing controller 140 converts the image signal VS received from the main controller 1010 according to a data signal format that can be processed by the data driver 120 , and outputs image data RGB. Accordingly, the timing controller 140 controls data driving at an appropriate time according to the scan.

The timing controller 140 may include a vertical sync signal Vsync, a vertical sync signal Hsync, a data enable signal (DE), a data clock signal DCLK, etc. together with the image signal VS. The timing signals TS are received from the main controller 1010 .

The timing controller 140 controls the data driver 120 and the gate driver 130 , a vertical synchronization signal Vsync, a vertical synchronization signal Hsync, a data enable signal DE, and a data clock signal DCLK. It receives the timing signal TS such as, etc., generates various control signals DCS and GCS, and outputs them to the data driver 120 and the gate driver 130 .

For example, the timing controller 140 controls the gate driver 130 , a gate start pulse (GSP), a gate shift clock (GSC), and a gate output enable signal (Gate Output). Various gate control signals (GCS) including Enable (GOE) and the like are output.

Here, the gate start pulse controls the operation start timing of one or more gate circuits constituting the gate driver 130 . The gate shift clock is a clock signal commonly input to one or more gate circuits and controls shift timing of a scan signal (gate pulse). The gate output enable signal specifies timing information of one or more gate circuits.

In addition, the timing controller 140 controls the data driver 120 , a source start pulse (SSP), a source sampling clock (SSC), a source output enable signal (Source Output Enable; Various data control signals (DCS) including SOE) are output.

Here, the source start pulse controls the data sampling start timing of one or more data circuits constituting the data driver 120 . The source sampling clock is a clock signal that controls the sampling timing of data in each of the data circuits. The source output enable signal controls the output timing of the data driver 120 .

The timing controller 140 is a control connected to the source printed circuit board to which the data driver 120 is bonded through a connection medium such as a flexible flat cable (FFC) or a flexible printed circuit (FPC). It may be disposed on a printed circuit board (Control Printed Circuit Board).

A power control unit for supplying various voltages or currents to the display panel 110 , the data driver 120 , and the gate driver 130 , or controlling various voltages or currents to be supplied may be further disposed on the control printed circuit board. The power control unit may be referred to as a power management integrated circuit (PMIC).

The above-described source printed circuit board and control printed circuit board may be configured as one printed circuit board.

The gate driver 130 sequentially supplies a gate voltage of an on voltage or an off voltage to the gate lines GL1 to GLm under the control of the timing controller 140 .

The gate driver 130 may be positioned on only one side of the display panel 110 or, in some cases, on both sides, depending on a driving method.

The gate driver 130 is connected to a bonding pad of the display panel 110 by a Tape Automated Bonding (TAB) method or a Chip On Glass (COG) method, or a gate (GIP) method. In Panel) type and may be disposed directly on the display panel 110 , or may be integrated and disposed on the display panel 110 in some cases.

The gate driver 130 may include a shift register, a level shifter, and the like.

The data driver 120 converts the image data RGB received from the timing controller 140 into an analog data voltage and outputs it to the data lines DL1 to DLn.

The data driver 120 may be connected to a bonding pad of the display panel 110 by a tape automated bonding method or a chip-on-glass method or may be directly disposed on the display panel 110 , and in some cases, the display panel 110 . It may be integrated and disposed in the

Also, the data driver 120 may be implemented in a Chip On Film (COF) method. In this case, one end of the data driver 120 may be bonded to at least one source printed circuit board, and the other end may be bonded to the display panel 110 .

The data driver 120 may include a logic unit including various circuits such as a level shifter and a latch unit, a digital analog converter (DAC), an output buffer, and the like.

3 is a circuit diagram illustrating driving of pixels disposed in a display device included in a video wall device according to an embodiment of the present invention.

The driving of each pixel Px will be described with reference to FIG. 3 as follows. First, the switching transistor ST is turned on by the gate voltage supplied to the gate lines GL1 to GLm of each pixel Px. In addition, the data voltage Vdata is supplied from the data lines DL1 to DLn by the turned-on switching transistor ST, and the driving current i is increased by the driving transistor DT applied thereto. Controlled. Finally, the organic light emitting diode OLED displays an image by emitting light corresponding to the controlled driving current i.

4 is a schematic block diagram illustrating a main controller included in a video wall device according to an embodiment of the present invention.

As shown in FIG. 4 , the main controller 1010 includes an image average level calculator 1011 , a peak luminance controller 1013 , a Gaussian curve setter 1015 , and a gain determiner 1017 .

The image average level calculator 1011 calculates an average image level (APL) representing an average grayscale of divided images output to each of the display panels 110 to 910 .

Here, the image average level APL refers to an average grayscale percentage value of the pixels Px of each of the display panels 110 to 910 in one frame. Specifically, since each pixel Px may include a red sub-pixel implementing red, a green sub-pixel implementing green, and a blue sub-pixel implementing blue, the image average level APL is also the grayscale of the red sub-pixel. , may be calculated in consideration of the grayscale of the green sub-pixel and the grayscale of the blue sub-pixel.

The method of calculating the average image level APL may be different depending on detailed settings of the average image level APL, but may be described through Equation 1 as an example.

[Equation 1]

Here, R is the gray level of the red sub-pixel, B is the gray level of the green sub-pixel, B is the gray level of the blue sub-pixel, and γ is the gamma value of the display panels 110 to 910 , which may be set to 2.2. have.

According to Equation 1, it can be seen that the image average level APL is determined by the maximum grayscale value among the grayscale of the red sub-pixel, the grayscale of the green sub-pixel, and the grayscale of the blue sub-pixel. .

5 is a graph for explaining an operation of a peak luminance controller included in a video wall device according to an embodiment of the present invention.

Next, the peak luminance controller 1013 controls the peak luminance PL of the display panels 110 to 910 based on the image average level APL.

Here, the peak luminance PL of the display panels 110 to 910 refers to the maximum luminance among the luminances of the display panels 110 to 910 . That is, the peak luminance PL may mean the luminance in the central portion of the display panel 110 to 910 , but is not limited thereto and refers to the maximum luminance in the entire position of the display panel 110 to 910 .

Also, as the average image level APL increases, the peak luminance PL may decrease. The method of controlling the peak luminance PL may be different for each setting of the display panels 110 to 910 , but may be described by Equation 2 as an example.

[Equation 2]

Specifically, referring to FIG. 5 , when the average image level (APL) is 25% or more, it is possible to control the peak luminance (PL) to decrease relatively rapidly, and when the average image level (APL) is 25% or less, it is possible to relatively It can be controlled so that the peak luminance PL is gently decreased.

In the case of an image having a low image average level (APL), the display panels 110 to 910 having high luminance can be implemented by increasing the peak luminance (PL), and in the case of an image having a high image average level (APL), the peak luminance (PL) is increased. PL) is lowered to reduce power consumption.

6 is a graph illustrating luminance of a display panel provided in a video wall device according to an exemplary embodiment of the present invention.

The Gaussian curve setting unit 1015 sets the luminance of each of the display panels 110 to 910 to conform to the Gaussian curve based on the calculated average image level APL.

Here, that the luminance of the display panels 110 to 910 follows a Gaussian curve means that the luminance of the display panels 110 to 910 is set so that the luminance of the central portion of the display panel 110 to 910 becomes the peak luminance PL. It means that is set by the Gaussian function described in Equation (3).

[Equation 3]

Here, x denotes a position in a first axial direction, y denotes a position in a second axial direction perpendicular to the first axial direction, and G denotes a luminance gain, which will be described later. Here, the Gaussian curve setting unit 1015 sets the gain to 1 and sets the Gaussian curve. In addition, since the display panels 110 to 910 are generally two-dimensional, Gaussian curves are respectively set for the first axis and the second axis. However, hereinafter, for convenience of explanation, the first axis is used as a reference.

Referring to FIG. 6 , the luminance along the Gaussian curve is set to be symmetrical with respect to the central portion of the display panels 110 to 910 . And, since the first sigma value (σ1) is smaller than the second sigma (σ2), the curvature of the first Gaussian curve (Gaussian 1) by the first sigma (σ1) is the second Gaussian by the second sigma (σ2) It is greater than the curvature of the curve (Gaussian 2). That is, as the sigma value increases, the curvature of the Gaussian curve decreases.

Also, as the curvature of the Gaussian curve decreases, the overall luminance of the display panels 110 to 910 to which the Gaussian curve is applied is relatively high. Specifically, assuming that the percentage value of the total luminance of the display panels 110 to 910 to which the Gaussian curve is not applied is 100%, the total luminance of the display panels 110 to 910 to which the first Gaussian curve Gaussian 1 is applied. The percentage value of is 86%, while the percentage value of the total luminance of the display panels 110 to 910 to which the second Gaussian curve Gaussian 2 is applied is 65%.

Based on this content, the Gaussian curve setting unit 1015 sets the Gaussian curve to increase the percentage value of the total luminance of the display panels 110 to 910 as the calculated average image level APL increases. In other words, the Gaussian curve setting unit 1015 sets the curvature of the Gaussian curve to decrease as the calculated average image level APL increases.

Then, the sigma values (σ _x , σ _y ) according to the set Gaussian curve are determined through Equation (4).

[Equation 4]

For example, the percentage value of the total luminance of the display panels 110 to 910 to which the Gaussian curve set by the Gaussian curve setting unit 1015 is applied according to the image average level APL and the sigma value thereof are described in Table 1.

[Table 1]

In summary, as the image average level APL increases, the peak luminance PL decreases by the peak luminance controller 1013 , but the Gaussian curve setting unit 1015 controls the total luminance of the display panels 110 to 910 to which the Gaussian curve is applied. increase the percentage value of Conversely, as the image average level APL decreases, the peak luminance PL increases by the peak luminance controller 1013, but the Gaussian curve setting unit 1015 controls the total luminance of the display panels 110 to 910 to which the Gaussian curve is applied. Decrease the percentage value.

Accordingly, the peak luminance control unit 1013 and the Gaussian curve setting unit 1015 adjust the peak luminance PL and the overall luminance of the display panels 110 to 910, respectively, to thereby adjust the image average level between the plurality of display panels 110 to 910 . Even if there is a large difference in APL, the difference in overall luminance between the plurality of display panels 110 to 910 may be reduced. Accordingly, the difference in overall luminance of each of the display panels 110 to 910 is reduced below the viewer's perception level, so that the quality of the entire image of the video wall apparatus 1000 may be improved.

7 is a schematic block diagram illustrating a gain determiner included in a video wall device according to an embodiment of the present invention.

7 , the gain determining unit 1017 includes a region of interest setting unit 1017a, a complexity calculating unit 1017b, a current consumption value calculating unit 1017c, and a gain setting unit 1017d.

As described above, the Gaussian curve setting unit 1015 sets the gain to 1 and sets the Gaussian curve. Accordingly, the gain determiner 1017 synthesizes a region of interest (ROI), an image complexity (IC), and a current consumption (CC) of each of the display panels 110 to 910 . In consideration of this, the gain set to 1 is determined as a specific value.

The region of interest setting unit 1017a sets a region of interest (ROI) in each video wall device 1000 . Here, the region of interest (ROI) may mean a segmented image to be emphasized as necessary among images displayed on the video wall apparatus 1000 , and may refer to a segmented image that is variable according to a viewer's position.

Accordingly, the region of interest setting unit 1017a stores information on the display panels 110 to 910 on which a preset region of interest (ROI) is arranged, or tracks the position of a viewer so that the region of interest (ROI) is arranged in real time. Information on the display panels 110 to 910 may be grasped.

8 is a diagram illustrating a plurality of display areas disposed on a display panel provided in a video wall device according to an embodiment of the present invention.

The complexity calculator 1017b analyzes the images output from each of the display panels 110 to 910 to analyze the complexity (IC) of each image.

Here, the image complexity (IC) is an index indicating how complex the images output from the display panels 110 to 910 are. This may be interpreted in various meanings according to settings, but may mean, for example, a difference in gradation between adjacent display areas PA in one display panel 110 to 910 .

Specifically, referring to FIG. 8 , the display panels 110 to 910 include display areas PA(1,1) disposed in the first row and first column to the display areas PA(1,1) disposed in the p-th row and the q-th row. PA(p,q)). Here, the gray level of the display area PA(2,2) disposed in the second row and second column and eight display areas adjacent to the display area PA(2,2) disposed in the second row and second column The image complexity (IC) is calculated by averaging the difference between the gray levels of (PA(1,1) to PA(3,3)) and converting it into a percentage value. That is, by setting both i and j to 2 according to Equation 5, the complexity IC of the image of the display area PA(2,2) disposed in the second row and second column may be calculated.

[Equation 5]

Here, g denotes a grayscale of the display area, and 1/8 denotes an average of grayscale differences between the central display area and the display area adjacent thereto.

Next, the current consumption value calculator 1017c calculates the current consumption values CC of each of the display panels 110 to 910 based on the average luminance values of the display panels 110 to 910 .

In more detail, the current consumption value CC of the display panel 110 to 910 is the sum of the current consumption values CC of the plurality of pixels Px of the display panel 110 to 910 . And, the current consumption value CC of each pixel Px may be calculated through Equation (6).

[Equation 6]

Here, the pixel current consumption means the current consumption value (CC) of each pixel Px, the average luminance means the average luminance of the display panels 110 to 910, and the efficiency means the efficiency of the organic light emitting diode (OLED). means, and Transmissivity means the transmittance of the polarizer.

In addition, current consumption values CC of the display panels 110 to 910 are calculated by summing all current consumption values CC of the pixels Px calculated in this way.

In addition, the gain setting unit 1017d is configured to operate the display panels 110 to 910 based on the set region of interest (ROI), the calculated image complexity (IC), and the current consumption values (CC) of the display panels 110 to 910 . Determines the overall luminance gain.

The gain setting unit 1017d increases the luminance gain of the display panels 110 to 910 corresponding to the set ROI. Specifically, the gain setting unit 1017d sets the gain of the total luminance of the display panels 110 to 910 corresponding to the set region of interest ROI to be 1 or more, and the total luminance of the other display panels 110 to 910 . By setting the gain of 1 or less, the segmented image output to the region of interest (ROI) can be emphasized.

Also, the gain setting unit 1017d increases the gain of the luminance of the display panels 110 to 910 as the calculated image complexity IC decreases. In the case of a simple image due to a low image complexity (IC), a decrease in luminance of the outer portion of the display panels 110 to 910 due to the Gaussian curve is highly likely to be recognized. Accordingly, when the image complexity IC is low, the luminance gain may be increased to prevent a luminance difference between the outer portions of the display panels 110 to 910 from being recognized. For example, when the complexity (IC) of the image is greater than or equal to the threshold, the gain may be set to 1.2, but the present invention is not limited thereto.

Finally, the gain setting unit 1017d increases a maximum current consumption value among current consumption values CC of the display panels 110 to 910 to a current limit of the display panels 110 to 910 . Thus, the gain of the overall luminance of the display panels 110 to 910 may be increased.

That is, the current consumption value CC of each of the display panels 110 to 910 is the maximum current consumption value among (allowable current limit/current consumption values CC of each of the display panels 110 to 910 ). (Max current)) times, it is possible to increase the gain of the luminance.

Specifically, Table 2 shows the current consumption values CC of the display panels 110 to 910 and the increased current consumption values (Gained CC) of the display panels 110 to 910 . According to Table 2, the current consumption of the fourth display panel 410 is 6.9A, which corresponds to the maximum current consumption, and in this case, the allowable current limit of the display panels 110 to 910 is 7.2. . Accordingly, the current consumption value CC of each of the display panels 110 to 910 is increased by (permissible current value (7.2A)/maximum consumption current value (6.9A)) times. That is, the current consumption value CC of each of the display panels 110 to 910 is increased by 1.04 times. Accordingly, the current consumption value (Gained CC) of the fourth display panel 410 increases to 7.2A, which is an allowable current value, and the current consumption values (Gained CC) of the other display panels 110 to 910 also increase.

[Table 2]

Accordingly, the current consumption value Gained CC of all the display panels 110 to 910 is increased, so that the luminance gain of all the display panels 110 to 910 is also increased, thereby increasing the overall luminance of the video wall device 1000 . It works.

As a result, the video wall device 1000 according to an embodiment of the present invention adjusts the peak luminance PL and the total luminance of the display panels 110 to 910 to thereby adjust the average image level ( Even if there is a large difference in APL), a difference in overall luminance between the plurality of display panels 110 to 910 may be reduced. Accordingly, the difference in overall luminance of each of the display panels 110 to 910 is reduced below the viewer's perception level, so that the quality of the entire image of the video wall apparatus 1000 may be improved.

In addition, the video wall device 1000 according to an embodiment of the present invention comprehensively considers a region of interest (ROI), an image complexity (IC), and a current consumption value (CC) of each of the display panels 110 to 910 . Accordingly, there is an effect of increasing the luminance gain of the entire display panel 110 to 910 to increase the luminance of the entire video wall apparatus 1000 .

Hereinafter, a method of driving a video wall device according to an embodiment of the present invention will be described in detail with reference to FIGS. 9 and 10 .

9 is a flowchart illustrating a method of driving a video wall device according to an embodiment of the present invention.

As shown in FIG. 9 , the video wall device driving method ( S100 ) includes an image average level calculation step ( S110 ), a peak luminance control step ( S120 ), a Gaussian curve setting step ( S130 ), and a gain determination step ( S140 ). include

In the image average level calculation step S110 , an average image level (APL) representing the average grayscale of the divided images output to each of the display panels 110 to 910 is calculated.

Here, the image average level APL refers to an average grayscale percentage value of the pixels Px of each of the display panels 110 to 910 in one frame. Specifically, since each pixel Px may include a red sub-pixel implementing red, a green sub-pixel implementing green, and a blue sub-pixel implementing blue, the image average level APL is also the grayscale of the red sub-pixel. , may be calculated in consideration of the grayscale of the green sub-pixel and the grayscale of the blue sub-pixel.

The method of calculating the average image level APL may be different depending on detailed settings of the image average level APL, but may be described through Equation 1 as an example.

[Equation 1]

Here, R is the gray level of the red sub-pixel, B is the gray level of the green sub-pixel, B is the gray level of the blue sub-pixel, and γ is the gamma value of the display panels 110 to 910 , which may be set to 2.2. have.

According to Equation 1, it can be seen that the image average level APL is determined by the maximum grayscale value among the grayscale of the red sub-pixel, the grayscale of the green sub-pixel, and the grayscale of the blue sub-pixel. .

Next, in the peak luminance control step S120 , the peak luminance PL of the display panels 110 to 910 is controlled based on the image average level APL.

Here, the peak luminance PL of the display panels 110 to 910 refers to the maximum luminance among the luminances of the display panels 110 to 910 . That is, the peak luminance PL may mean the luminance in the central portion of the display panel 110 to 910 , but is not limited thereto and refers to the maximum luminance in the entire position of the display panel 110 to 910 .

Also, as the average image level APL increases, the peak luminance PL may decrease. The method of controlling the peak luminance PL may be different for each setting of the display panels 110 to 910 , but may be described by Equation 2 as an example.

[Equation 2]

Specifically, referring to FIG. 5 , when the average image level (APL) is 25% or more, it is possible to control the peak luminance (PL) to decrease relatively rapidly, and when the average image level (APL) is 25% or less, it is possible to relatively It can be controlled so that the peak luminance PL is gently decreased.

In the case of an image having a low image average level (APL), the display panels 110 to 910 having high luminance can be implemented by increasing the peak luminance (PL), and in the case of an image having a high image average level (APL), the peak luminance (PL) is increased. PL) is lowered to reduce power consumption.

In the Gaussian curve setting step S130 , the luminance of each of the display panels 110 to 910 is set to conform to the Gaussian curve based on the calculated image average level APL.

Here, that the luminance of the display panels 110 to 910 follows a Gaussian curve means that the luminance of the display panels 110 to 910 is set so that the luminance of the central portion of the display panel 110 to 910 becomes the peak luminance PL. It means that is set by the Gaussian function described in Equation (3).

[Equation 3]

Here, x denotes a position in a first axial direction, y denotes a position in a second axial direction perpendicular to the first axial direction, and G denotes a luminance gain, which will be described later. Here, in the Gaussian curve setting step ( S130 ), the gain is set to 1, and the Gaussian curve is set. In addition, since the display panels 110 to 910 are generally two-dimensional, Gaussian curves are respectively set for the first axis and the second axis. However, hereinafter, for convenience of explanation, the first axis is used as a reference.

Referring to FIG. 6 , the luminance along the Gaussian curve is set to be symmetrical with respect to the central portion of the display panels 110 to 910 . And, since the first sigma value (σ1) is smaller than the second sigma (σ2), the curvature of the first Gaussian curve (Gaussian 1) by the first sigma (σ1) is the second Gaussian by the second sigma (σ2) It is greater than the curvature of the curve (Gaussian 2). That is, as the sigma value increases, the curvature of the Gaussian curve decreases.

Also, as the curvature of the Gaussian curve decreases, the overall luminance of the display panels 110 to 910 to which the Gaussian curve is applied is relatively high. Specifically, assuming that the percentage value of the total luminance of the display panels 110 to 910 to which the Gaussian curve is not applied is 100%, the total luminance of the display panels 110 to 910 to which the first Gaussian curve Gaussian 1 is applied. The percentage value of is 86%, while the percentage value of the total luminance of the display panels 110 to 910 to which the second Gaussian curve Gaussian 2 is applied is 65%.

Based on this content, the Gaussian curve setting step S130 sets the Gaussian curve to increase the percentage value of the total luminance of the display panels 110 to 910 as the calculated average image level APL increases. In other words, the Gaussian curve setting step S130 sets the curvature of the Gaussian curve to decrease as the calculated average image level APL increases.

Then, the sigma values (σ _x , σ _y ) according to the set Gaussian curve are determined through Equation (4).

[Equation 4]

For example, the percentage value of the total luminance of the display panels 110 to 910 to which the Gaussian curve set in the Gaussian curve setting step S130 according to the image average level APL is applied, and the sigma value thereof are described in Table 1.

[Table 1]

In summary, as the image average level APL increases, the peak luminance PL decreases by the peak luminance control step S120 , but the entire display panels 110 to 910 to which the Gaussian curve is applied in the Gaussian curve setting step S130 . Increases the percentage value of luminance. Conversely, as the image average level APL decreases, the peak luminance PL increases by the peak luminance control step S120 , but the overall luminance of the display panels 110 to 910 to which the Gaussian curve is applied in the Gaussian curve setting step S130 . decreases the percentage value of

Accordingly, in the peak luminance control step S120 and the Gaussian curve setting step S130 , the peak luminance PL and the overall luminance of the display panels 110 to 910 are adjusted, respectively, and the average image between the plurality of display panels 110 to 910 is performed. Even if there is a large difference in the level APL, a difference in overall luminance between the plurality of display panels 110 to 910 may be reduced. Accordingly, the difference in overall luminance of each of the display panels 110 to 910 is reduced below the viewer's perception level, so that the quality of the entire image of the video wall apparatus 1000 may be improved.

10 is a flowchart illustrating a gain determination step of a method of driving a video wall device according to an embodiment of the present invention.

As shown in FIG. 10 , the gain determination step S140 includes a region of interest setting step S141 , a complexity calculation step S142 , a current consumption value calculation step S143 , and a gain setting step S144 .

As described above, in the Gaussian curve setting step (S130), the gain was set to 1 and the Gaussian curve was set. Accordingly, in the gain determining step S140 , a region of interest (ROI), an image complexity (IC), and a current consumption (CC) of each display panel 110 to 910 are synthesized. Considering , the gain set to 1 is determined as a specific value.

In the region of interest setting step S141 , a region of interest (ROI) in each video wall device 1000 is set. Here, the region of interest (ROI) may mean a segmented image to be emphasized as necessary among images displayed on the video wall apparatus 1000 , and may refer to a segmented image that is variable according to a viewer's position.

Accordingly, in the region of interest setting step S141 , information on the display panels 110 to 910 on which the preset region of interest (ROI) is arranged is stored, or the position of the viewer is tracked and the region of interest (ROI) is arranged in real time. Information on the display panels 110 to 910 may be grasped.

Next, in the complexity calculation step ( S142 ), images output from each of the display panels 110 to 910 are analyzed to analyze the complexity (IC) of each image.

Here, the image complexity (IC) is an index indicating how complex the images output from the display panels 110 to 910 are. This may be interpreted in various meanings according to settings, but may mean, for example, a difference in gradation between adjacent display areas PA in one display panel 110 to 910 .

Specifically, referring to FIG. 8 , the display panels 110 to 910 include display areas PA(1,1) disposed in the first row and first column to the display areas PA(1,1) disposed in the p-th row and the q-th row. PA(p,q)). Here, the gray level of the display area PA(2,2) disposed in the second row and second column and eight display areas adjacent to the display area PA(2,2) disposed in the second row and second column The image complexity (IC) is calculated by averaging the difference between the gray levels of (PA(1,1) to PA(3,3)) and converting it into a percentage value. That is, by setting both i and j to 2 according to Equation 5, the complexity IC of the image of the display area PA(2,2) arranged in the second row and the second column may be calculated.

[Equation 5]

Here, g denotes a grayscale of the display area, and 1/8 denotes an average of grayscale differences between the central display area and the display area adjacent thereto.

Next, in the step of calculating the current consumption value ( S143 ), the current consumption value CC of each of the display panels 110 to 910 is calculated based on the average luminance values of the display panels 110 to 910 .

In more detail, the current consumption value CC of the display panel 110 to 910 is the sum of the current consumption values CC of the plurality of pixels Px of the display panel 110 to 910 . And, the current consumption value CC of each pixel Px may be calculated through Equation (6).

[Equation 6]

Here, the pixel current consumption means the current consumption value (CC) of each pixel Px, the average luminance means the average luminance of the display panels 110 to 910, and the efficiency means the efficiency of the organic light emitting diode (OLED). means, and Transmissivity means the transmittance of the polarizer.

In addition, current consumption values CC of the display panels 110 to 910 are calculated by summing all current consumption values CC of the pixels Px calculated in this way.

In addition, in the gain setting step S144 , the display panels 110 to 910 are based on the set region of interest (ROI), the calculated image complexity (IC), and the current consumption values (CC) of the display panels 110 to 910 . Determines the overall luminance gain.

In the gain setting step S144, the gain of the luminance of the display panels 110 to 910 corresponding to the set ROI is increased. Specifically, in the gain setting step S144 , the gain of the total luminance of the display panels 110 to 910 corresponding to the set ROI is set to 1 or more, and the total luminance of the other display panels 110 to 910 is set. By setting the gain of 1 or less, the segmented image output to the region of interest (ROI) can be emphasized.

In addition, in the gain setting step S144 , as the calculated image complexity IC is lower, the luminance gain of the display panels 110 to 910 is increased. In the case of a simple image due to a low image complexity (IC), a decrease in luminance of the outer portion of the display panels 110 to 910 due to the Gaussian curve is highly likely to be recognized. Accordingly, when the image complexity IC is low, the luminance gain may be increased to prevent a luminance difference between the outer portions of the display panels 110 to 910 from being recognized. For example, when the complexity (IC) of the image is greater than or equal to the threshold, the gain may be set to 1.2, but the present invention is not limited thereto.

Finally, in the gain setting step S144 , the maximum current consumption value among the current consumption values CC of the display panels 110 to 910 is increased to the allowable current value of the display panels 110 to 910 . Thus, the gain of the overall luminance of the display panels 110 to 910 may be increased.

That is, the current consumption value CC of each of the display panels 110 to 910 is the maximum current consumption value among (allowable current limit/current consumption values CC of each of the display panels 110 to 910 ). (Max current)) times, it is possible to increase the gain of the luminance.

Specifically, Table 2 shows the current consumption values CC of the display panels 110 to 910 and the increased current consumption values (Gained CC) of the display panels 110 to 910 . According to Table 2, the current consumption of the fourth display panel 410 is 6.9A, which corresponds to the maximum current consumption, and in this case, the allowable current limit of the display panels 110 to 910 is 7.2. . Accordingly, the current consumption value CC of each of the display panels 110 to 910 is increased by (permissible current value (7.2A)/maximum consumption current value (6.9A)) times. That is, the current consumption value CC of each of the display panels 110 to 910 is increased by 1.04 times. Accordingly, the current consumption value (Gained CC) of the fourth display panel 410 increases to 7.2A, which is an allowable current value, and the current consumption values (Gained CC) of the other display panels 110 to 910 also increase.

[Table 2]

Accordingly, the current consumption value Gained CC of all the display panels 110 to 910 is increased, so that the luminance gain of all the display panels 110 to 910 is also increased, thereby increasing the overall luminance of the video wall device 1000 . It works.

As a result, in the method ( S100 ) of driving a video wall device according to an embodiment of the present invention, the peak luminance PL and the total luminance of the display panels 110 to 910 are adjusted, so that an image between the plurality of display panels 110 to 910 is adjusted. Even if there is a large difference in the average level APL, the difference in overall luminance between the plurality of display panels 110 to 910 may be reduced. Accordingly, the difference in overall luminance of each of the display panels 110 to 910 is reduced below the viewer's perception level, so that the quality of the entire image of the video wall apparatus 1000 may be improved.

In addition, in the method S100 of driving a video wall device according to an embodiment of the present invention, the region of interest (ROI), the complexity of the image (IC), and the current consumption values (CC) of each of the display panels 110 to 910 are calculated. In general, by increasing the luminance gain of all the display panels 110 to 910 , there is an effect of increasing the overall luminance of the video wall apparatus 1000 .

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 various modifications may be made within the scope without departing from the technical spirit of the present invention. . Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit 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 by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

1000: video wall device
1010: main control unit
1011: video average level calculator
1013: peak luminance control unit
1015: Gaussian curve setting unit
1017: gain determining unit
1017a: region of interest setting unit
1017b: Complexity calculator
1017c: current consumption value calculation unit
1017d: gain setting unit

Claims (15)

a plurality of display devices; and
a main control unit for outputting image signals to the plurality of display devices;
The main control unit,
an image average level calculator configured to calculate an average image level of images output from a display panel of each display device;
a peak luminance controller configured to control a peak luminance of each of the display panels based on the average image level;
a Gaussian curve setting unit configured to set the luminance of each display panel to conform to a Gaussian curve for a position of the display panel based on the image average level;
and a gain determiner configured to determine a gain of luminance of each of the display panels. According to claim 1,
The peak luminance control unit
and decreasing the peak luminance as the average image level increases. According to claim 1,
The Gaussian curve setting unit,
and setting the Gaussian curve such that a luminance of a central portion of the display panel becomes the peak luminance. According to claim 1,
The Gaussian curve setting unit
The video wall device, which decreases the curvature of the Gaussian curve as the average level of the image increases. According to claim 1,
The gain determining unit
a region of interest setting unit configured to set a region of interest in the video wall device;
a complexity calculator configured to calculate a complexity of an image output from each of the display panels;
a current consumption value calculator configured to calculate a current consumption value of each of the display panels; and
and a gain setting unit configured to set a luminance gain of each of the display panels based on the set region of interest, the complexity of the image, and the current consumption value. 6. The method of claim 5,
The gain setting unit
The video wall apparatus of claim 1, wherein the luminance gain is increased as the complexity of the image is lower. 6. The method of claim 5,
The gain setting unit
and increasing a gain of a luminance of a display panel corresponding to the set ROI. 6. The method of claim 5,
The gain setting unit
and increasing the gain of the luminance by increasing the current consumption of each of the display panels by a factor of (permissible current value/maximum consumption current value among the current consumption values of each of the display panels). A method of driving a video wall device having a plurality of display panels, the method comprising:
an image average level calculating step of calculating an image average level of images output from each display panel;
a peak luminance control step of controlling a peak luminance of each of the display panels based on the image average level;
a Gaussian curve setting step of setting the luminance of each display panel to conform to a Gaussian curve for a position of the display panel based on the image average level;
and a gain determining step of determining a luminance gain of each of the display panels. 10. The method of claim 9,
In the peak luminance control step
and decreasing the peak luminance as the average image level increases. 10. The method of claim 9,
In the Gaussian curve setting step
The method of driving a video wall device, wherein the higher the image average level, the lower the curvature of the Gaussian curve. 10. The method of claim 9,
The gain determining step is
a region of interest setting step of setting a region of interest in the video wall device;
a complexity calculation step of calculating a complexity of an image output from each of the display panels;
a current consumption value calculation step of calculating a current consumption value of each of the display panels;
and a gain setting step of setting a luminance gain of each of the display panels based on the set region of interest, the complexity of the image, and the current consumption value. 13. The method of claim 12,
In the above gain setting step
and increasing the gain of the luminance as the complexity of the image decreases. 13. The method of claim 12,
In the above gain setting step
and increasing a luminance gain of a display panel corresponding to the set ROI. 13. The method of claim 12,
In the above gain setting step
and increasing the gain of the luminance by increasing the current consumption of each of the display panels by a factor of (permissible current value/maximum consumption current value among current consumption values of each display panel).

Images