KR100667112B1 - Plasma display apparatus and method of the same - Google Patents

Abstract

A plasma display device and a driving method thereof are provided to reduce power consumption of the plasma display device by decreasing a displacement current by adjusting the gains of respective frames. A frame memory(300) stores data and calculates the APL(Average Picture Level) of the data. An inverse gamma compensator(310) linearly changes the brightness to the gradation values of image signals. A gain adjuster(320) adjusts the effective gains of red, green, and blue data. A dithering unit(330) performs dithering on an image signal to finely change the brightness of the image signal. A sub-field mapper(340) maps the data from the dithering unit to a pre-stored sub-field pattern in a bitwise manner. A data arranging unit(350) supplies digital video data from the sub-field mapper to a data driver. A switching counter(360) calculates the generation degree of a displacement current at every frame by using the sub-field data from the sub-field mapper.

Description

Plasma display device and driving method thereof {PLASMA DISPLAY APPARATUS AND METHOD OF THE SAME}

1 is a diagram illustrating one frame of a typical plasma display panel.

Fig. 2 is an equivalent circuit diagram equivalently showing the capacitance of the PDP.

3 is a diagram schematically illustrating an example of a data processing scheme that causes power consumption and heat generation according to switching of a data driver IC;

4 is a diagram schematically showing another example of a data processing method that causes power consumption and heat generation according to switching of a data driver IC.

5 is a diagram illustrating a data control apparatus of a plasma display panel according to an exemplary embodiment of the present invention.

6 is a view showing a method for determining whether displacement current is generated for each cell according to the present invention.

7 is a flowchart illustrating a gain adjustment method according to the present invention.

8 is a view showing a gain adjusting method according to the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data control method and apparatus for a plasma display panel, and more particularly, to reducing power consumption and heat generation of a data driving circuit by reducing a displacement current by adjusting a gain value of each frame according to a switching load. The present invention relates to a display device and a driving method.

1 is a diagram illustrating one frame of a general plasma display panel.

Recently, there is a growing interest in flat panel displays that can reduce the weight and volume of cathode ray tubes. Such a flat panel display includes a liquid crystal display (hereinafter referred to as "LCD"), a plasma display panel (hereinafter referred to as "PDP"), a field emission display (hereinafter referred to as "PDP"). FED ", and electroluminescence (hereinafter referred to as" EL "), and the like, and supply digital signals or analog data to the display panel.

In such a flat panel display, the PDP displays an image including text or graphics by emitting phosphors by 147 nm ultraviolet rays generated when discharge of an inert mixed gas such as He + Xe, Ne + Xe or He + Ne + Xe. . Such a PDP is not only thin and easy to enlarge, but also greatly improved in quality due to recent technology development. In particular, the three-electrode AC surface discharge type PDP has advantages of low voltage driving and long life because wall charges are accumulated on the surface during discharge and protect the electrodes from sputtering caused by the discharge.

The PDP is driven by dividing one frame into several subfields with different number of flashes in order to express the gray level of an image. Each subfield is further divided into a reset period for uniformly generating discharge, an address period for selecting a discharge cell, and a sustain period for implementing gray scale according to the number of discharges. When the image is to be displayed in 256 gray levels, a frame period (16.67 ms) corresponding to 1/60 second is divided into eight subfields SF1 to SF8 as shown in FIG. Each of the eight subfields SF1 to SF8 is divided into a reset period, an address period, and a sustain period. The reset period and the address period of each subfield are the same for each subfield, while the sustain period and the number of discharges thereof are 2n in each subfield (where n = 0,1,2,3,4,5,6,7). Is increased by the ratio. In this way, since the sustain period is different in each subfield, the gray level of the image can be expressed.

However, PDP has a large power consumption because the driving voltage is relatively high due to the discharge characteristics causing the discharge between the two electrodes and the large panel size. In addition, the driver integrated circuit (hereinafter, referred to as 'IC') for driving the data electrode and the scan electrode of the PDP has to supply a high voltage to each of the electrodes Y, Z, and X in order to cause discharge. High power consumption and high heat generation

Most of the power consumption of the PDP is consumed in the sustain period, and then much in the subsequent address period. For example, the sustain period requires several hundred watts of power, and the address period requires tens of watts of power. The power consumption during the sustain period is mainly increased by the efficiency of the PDP. The power consumption in the address period increases and decreases according to the capacitance value C of the PDP, the voltage V, and the switching frequency of the driver IC.

Fig. 2 is an equivalent circuit diagram equivalently showing the capacitance of the PDP.

As shown in FIG. 2, the capacitance C of the PDP includes the capacitance C1 between the data electrodes X1 to Xn, and the capacitance C2 between the data electrodes X1 to Xn and the scan electrodes Y1 to Ym. And the capacitance C3 between the scan electrodes Y1 to Ym and the common sustain electrode Z, and the capacitance C4 between the address electrode X and the common sustain electrode Z. More than 90% of the power consumption in the address period is generated by the displacement current generated during charging / discharging of the PDP. In the power consumption of the address period, the power consumption generated by the displacement current can be expressed by Equation 1 below.

P = IV = CV2f

Where I is the current, V is the voltage of the data pulse, C is the capacitance value between the address electrode X and the other electrodes Y and Z adjacent thereto, f is the frequency, and average switching per unit time of the data driver IC. The number of times.

When the energy recovery circuit is employed in the data driver IC as described above, the power consumption of the data driver IC can be expressed by Equation (2).

P = IV = CV2f (1-a)

Here, a represents the energy recovery efficiency by the energy recovery circuit. In the data driver IC, the energy recovery efficiency a is about 0.5 at most.

As can be seen from Equations 1 and 2, in order to reduce the power consumption of the address period, a method of lowering the displacement current (I) by lowering the number of charge / discharge cycles, a method of lowering the data voltage (V), and a power failure of the PDP There is a method of lowering the capacitance C and a method of reducing the number of times f of the data driver IC. However, the method of lowering the data voltage (V) is limited because it is a voltage that can cause discharge in the discharge cell, and there is a limit in reducing the capacitance of the PDP in that the PDP is aimed at high resolution / large screen size.

The switching frequency f of the data driver IC is maximum when a data pattern in which high logic and low logic are repeated in both the column direction and the low direction is input. This will be described in detail with reference to FIG. 3.

3 is a diagram schematically illustrating an example of a data processing method that causes power consumption and heat generation according to switching of a data driver IC.

The number of times f of switching of the data driver IC is shown in FIG. 3 when performing a data processing method in which high logic and low logic are repeated in both the column direction and the row direction of each sub pixel cell (one discharge cell) 100. It is set to maximum. In other words, the data driver IC repeats the switching elements on and off every horizontal period when the data pattern shown in FIG. 3 is input.

Here, when the switching elements of the data driver IC repeat on / off every horizontal period, high power consumption is consumed and heat generation of the data driver IC occurs.

In fact, if the data processing method as shown in FIG. 3 is continuously performed for a predetermined time or more, high heat is generated in the data driver IC, and the data driver IC may be damaged by this heat.

4 is a diagram schematically illustrating another example of a data processing method that causes power consumption and heat generation according to switching of a data driver IC.

As shown in FIG. 4, the switching frequency f of the data driver IC is a column direction of each pixel cell 200 in which the red subpixel cell R, the green subpixel cell G, and the blue subpixel cell B are combined and partitioned. It is also set high when performing a data processing method in which high logic and low logic are repeated in both the and low directions. In other words, when performing the data processing method as shown in FIG. 4, the data driver IC repeats on / off of the switching elements every horizontal period. Accordingly, high power consumption is consumed and high heat is generated.

In addition, the capacitance C of the PDP is also set high when a data processing method having a large voltage difference, that is, a data processing method as shown in FIGS. 3 and 4, is performed in units of adjacent pixel cells or sub-pixel cells.

As can be seen from the above, in the data processing method as shown in FIGS. 3 and 4, the capacitance of the PDP and the number of times of switching of the data driver IC are increased so that the displacement current is increased by the amount of power consumption and heat generation.

The present invention is to solve the above-mentioned problems, an object of the present invention is to reduce the power consumption and heat generation of the data driving circuit by reducing the displacement current by adjusting the gain (gain) of each frame according to the switching rod. An object of the present invention is to provide a data control method and apparatus for a plasma display panel.

A data control apparatus of a plasma display panel according to the present invention includes a scan driver for scanning a scan electrode; A data driver supplying a data signal corresponding to a scan by the scan driver to the data electrode; And a control unit for generating a gain control reference value for a plurality of consecutive frames and controlling gain according to the gain control reference value.

The controller determines a switching level of each frame, and then generates a gain control reference value for a plurality of consecutive frames.

The control unit maintains a current gain value when the gain value exceeds a predetermined maximum value or is below a predetermined minimum value.

The control unit calculates a switching count according to values of adjacent cells belonging to m-1 rows, n columns and m rows, and n-1 columns in the case of cells belonging to m rows and n columns (m and n are natural numbers). do.

The controller calculates a switching count as 0 when the value of each cell and the value of the neighboring cell are the same, and as 1 when the remaining cells are the same.

The control unit determines the switching level by setting a value obtained by multiplying the switching count values of all cells and the number of subfields to a maximum value.

The controller may determine a switching level by setting 0 to a minimum value.

The controller may set a switching level by setting a threshold region between a maximum value and a minimum value.

The control unit sets the switching level by dividing the first section between the maximum value and the threshold region, the second section that is the threshold region section, and the third section between the threshold region and the minimum value section.

The controller may be configured to set a switching level by allocating a predetermined value to the first, second, and third sections.

The controller may generate a gain control reference value by summing switching levels of a plurality of consecutive frames.

The control unit may control to increase or decrease the gain by a value determined according to the gain control reference value.

A data control method of a plasma display panel according to the present invention includes the steps of calculating a switching count for each cell unit; Setting a switching level of each frame; Generating a gain control reference value for a plurality of consecutive frames; And controlling the gain according to the sum of the switching levels.

The data control method of the plasma display panel according to the present invention may further include maintaining a current gain value when the gain value exceeds the predetermined maximum value or is less than the predetermined minimum value.

The step of calculating the switching count in each cell unit is performed in the case of cells belonging to m rows, n columns (m and n are natural numbers), and the values of adjacent cells belonging to m-1 rows, n columns and m rows, and n-1 columns. And calculating the switching count accordingly.

The switching count is calculated as 0 when the value of each cell and the value of the neighboring cell are the same, and as 1 when the remaining cells are the same.

The setting of the switching level of each frame may include setting the switching level by setting a value obtained by multiplying the switching count values of all cells and the number of subfields to a maximum value.

In the setting of the switching level of each frame, the switching level is set by setting 0 to a minimum value.

The setting of the switching level of each frame may include setting a switching level by setting a threshold region between a maximum value and a minimum value.

The switching level is set by dividing the switching level by dividing the maximum value and the minimum value into a first section between a maximum value and a threshold value area, a second section that is a threshold value area section, and a third section between a threshold value range and a minimum value range. It is characterized by setting.

In the setting of the switching level, the switching level may be set by allocating a predetermined value to the first, second, and third sections.

The generating of the gain control reference value may include generating a gain control reference value by summing switching levels of a plurality of consecutive frames.

The controlling of the gain may include controlling the gain to increase or decrease by a value determined according to the gain control reference value.

DETAILED DESCRIPTION A detailed description of preferred embodiments of the present invention will now be described with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even if displayed on different drawings. In addition, in the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. The terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to a user's intention or custom, and the definitions should be made based on the contents throughout the specification.

5 is a diagram illustrating a data control apparatus of a plasma display panel according to an exemplary embodiment of the present invention.

Referring to FIG. 5, a data control apparatus of a PDP according to an exemplary embodiment of the present invention may include a frame memory unit 30, an inverse gamma correction unit 31, a gain adjusting unit 32, a dithering unit 33, and a subfield mapping unit. 34, a data alignment unit 35, and a switching count calculator 36.

The frame memory unit 30 stores data for APL calculation, and the inverse gamma correction unit 31 performs inverse gamma correction on the input digital video data R, G, and B to adjust luminance of the gray level of the image signal. Convert linearly.

The gain adjusting unit 42 adjusts the effective gain for each data of red, green, and blue. That is, the gain controller 820 may be a user or a set maker for the image signals of R (Red), G (Green), and B (Blue) that are inverse gamma corrected by the inverse gamma correction unit 810. Adjust the gain by red, green and blue by multiplying the gain that can be adjusted by). In the gain adjusting unit 42 according to the present invention, the gain value is adjusted according to the gain control reference value of the switching count calculation unit 36.

The dithering unit 33 dithers the image signal to realize fine luminance.

The subfield mapping unit 34 maps data input from the dithering unit 33 to subfield patterns stored in advance for each bit. The data alignment unit 35 supplies digital video data input from the subfield mapping unit 34 to the data driver.

The switching count calculator 36 calculates the generation level of the displacement current in units of frames by using the subfield data output from the subfield mapping unit 34. That is, the switching count calculator 36 generates a gain control reference value in a predetermined frame in succession, and adjusts the gain of the gain adjuster 42 according to the gain control reference value.

FIG. 6 is a diagram illustrating a method for determining whether a displacement current is generated for each cell according to the present invention. The present invention determines whether a displacement current is generated for all cells in each subfield.

As shown in FIG. 6, if it is desired to determine whether displacement current of any cell belonging to row M and column N is generated, adjacent cells belonging to row M-1 and column N and column M and column N-1 to be included Determine the state of the adjacent cell. At this time, it is set to 1 when the voltage is supplied to the cell and to 0 when the voltage is not supplied to the cell.

Table 1 is a table showing the switching count value according to whether or not displacement current of any cell belonging to the M row and N column according to the state of each cell.

(m, n) (m-1, n) (m, n-1) Switching count value 0 0 0 0 0 0 One One 0 One 0 One 0 One One One One 0 0 One One 0 One One One One 0 One One One One 0

As shown in Table 1, a switching count that is an output value when the state of any (m, n) cell is the same as the state of (m-1, n) or (m, n-1) cells that are adjacent cells Set the value to 0, otherwise set it to 1. In other words, if any one of the (m, n) cells and any of the adjacent cells are different from each other, a displacement current is generated in the (m, n) cells. At this time, the switching count value of any (m, n) cell becomes one.

This operation is performed for every subfield, and the switching count value for each cell is added to every subfield. The switching counting unit calculates a switching count value in units of frames, which is the sum of the values of every subfield.

On the other hand, as described above, the switching level is determined according to the switching count value in units of frames. That is, the switching count value in the unit of frame is the maximum value multiplied by the number of all cells and the number of subfields, and 0 is the minimum value. The threshold region is set between the maximum value and the minimum value. In this case, the switching counting unit sets the switching level to 2 when the switching count value of each frame unit is between the critical area and the maximum value, and sets the switching level to 1 when the switching count value of the frame unit corresponds to the critical area. If the unit's switching count value is between the critical range and the minimum value, it may be set to zero. As described above, when the switching level is set, the switching count unit calculates the final switching level by summing the values of the switching levels in units of 5 consecutive frames.

Table 2 shows a personal adjustment method for performing gain adjustment according to the final switching level.

Final switching level Gain adjustment result 0 5 5 bit increments every frame One 4 4 bit increments every frame 2 3 3 bits increase every frame 3 2 2 bits increase every frame 4 One 1 bit every frame 5 0 No change 6 -One 1 bit decrease every frame 7 -2 2 bits decrease every frame 8 -3 3 bit reduction every frame 9 -4 4 bit reduction every frame 10 -5 5 bit reduction every frame

The gain adjusting unit adjusts the gain according to the criteria set in Table 2, and when the gain adjustment is performed according to the criterion, the gain adjusting unit is adjusted to the final switching level when the current gain value exceeds the maximum value or is less than the predetermined minimum value. Retains the current gain value regardless. If the gain value is maximum, it means that the input and output are the same state, that is, the bypass state. The minimum value is set in consideration of the minimum amount of data for screen realization. If the value falls below the minimum value, the gain adjusting unit maintains the current gain value.

In the present invention, the gain range is set to 1024 as the maximum value and 0 as the minimum value. Therefore, if the gain value adjusted according to the criteria set in Table 2 exceeds 1024, the current gain value 1024 is maintained as it is.

For example, if the current gain value is 1020 and the switching level sum of 5 consecutive frames is 0, the gain value should be 1025 by receiving 5 more bits from the current gain value, but the gain value is exceeded to the maximum value of 1024. The value still keeps 1024.

Likewise, if the minimum value is set to 512, which is 50% of the maximum value, if the switching level sum of five consecutive frames is 10, if the current gain value is 515, it should be reduced to 5, which is 510, but to ensure the minimum value. The gain still remains at 512 for this purpose. If the gain range adjusted by the final switching level is within the maximum and minimum values, the gain adjuster adjusts the gain according to the criteria set in Table 2.

7 is a flowchart illustrating a gain adjusting method according to the present invention.

As described above, the present invention determines whether displacement current is generated for all cells in each subfield. Accordingly, when it is desired to determine whether a displacement current is generated in an arbitrary cell, the state of an adjacent cell is determined. At this time, it is set to 1 if the cell is supplied with a voltage and 0 if the cell is not supplied with a voltage, and a cell of any (m, n) cell is an adjacent cell (m-1, n), When all the states of the (m, n-1) cells are the same, the switching count value, which is an output value, is set to 0, and in all other cases, it is set to 1. That is, if any one of the (m, n) cells and any of the adjacent cells are different from each other, a displacement current is generated in the (m, n) cells. At this time, the switching count value of any (m, n) cell is 1 (S100).

This operation is performed for every subfield, and the switching count value for each cell is added to every subfield. The switching counting unit calculates a switching count value in units of frames, which is the sum of the values of every subfield.

On the other hand, as described above, the switching level is determined according to the switching count value in units of frames. That is, the switching count value in the unit of frame is the maximum value multiplied by the number of all cells and the number of subfields, and 0 is the minimum value. The threshold region is set between the maximum value and the minimum value. In this case, the switching counting unit sets the switching level to 2 when the switching count value of each frame unit is between the critical area and the maximum value, and sets the switching level to 1 when the switching count value of the frame unit corresponds to the critical area. When the switching count value of the unit is between the threshold region and the minimum value, it may be set to 0 (S110).

As described above, when the switching level is set, the switching count unit calculates a final switching level by summing values of the switching levels in units of 5 consecutive frames (S120).

The gain adjusting unit adjusts the gain according to the set criterion, and when performing the gain adjustment according to the criterion, determines whether the current gain value exceeds the maximum value or is less than the predetermined minimum value (S130).

If the current gain value exceeds the maximum value or is below the predetermined minimum value, the gain adjusting unit maintains the current gain value regardless of the final switching level. If the gain value is maximum, it means that the input and output are the same state, that is, the bypass state. The minimum value is a value set in consideration of the minimum amount of data for color realization. When the value falls below the minimum value, the gain adjusting unit maintains the current gain value (S140).

On the other hand, if the range of the gain value adjusted by the final switching level is within the maximum value and the minimum value, the gain adjusting unit adjusts the gain according to the set reference (S150).

8 is a view showing a gain adjusting method according to the present invention.

As described above, in the present invention, data processing is performed on a frame basis. Therefore, when an image signal is input for each frame (0, 1, 2, 3, 4, 5, ...), the switching level is determined for each frame. The method of determining the switching level is as described above.

Referring to FIG. 8, it can be seen that the switching levels of the first 5 frames (0, 1, 2, 3, 4) are 0, 0, 0, 0, and 2, respectively. Thus, the final switching level, which is the sum of the switching levels of five consecutive frames, becomes two. When the final switching level is 2, the gain value increases by 3 based on Table 2, but the current gain value is maintained as the current gain value is 1024, which is the maximum value.

In the case of the sixth frame, it can be seen that the switching levels of five consecutive frames (2, 3, 4, 5, 6) are 0, 0, 2, 2, and 2, respectively. Thus, the final switching level, which is the sum of the switching levels of five consecutive frames, is six. When the final switching level is 6, the gain value is reduced by 1 based on Table 2. At this time, since the gain value is 1024, the current gain value is 1023 with 1 decreased.

Similarly, in the case of the eighth frame, it can be seen that the switching levels of five consecutive frames 4, 5, 6, 7, and 8 are 2, 2, 2, 2, and 2, respectively. Thus, the final switching level, which is the sum of the switching levels of five consecutive frames, is ten. If the final switching level is 10, the gain value is reduced by 5 based on Table 2. At this time, since the gain value is 1020, the current gain value is 1015 with 5 decreased.

The technical spirit of the present invention has been described above with reference to the accompanying drawings, but this is by way of example only and not intended to limit the present invention. In addition, it is obvious that any person skilled in the art can make various modifications and imitations without departing from the scope of the technical idea of the present invention.

The present invention can reduce the power consumption and heat generation of the data driving circuit by reducing the displacement current by adjusting the gain (gain) of each frame according to the switching rod.

Claims (23)

A scan driver scanning the scan electrode; A data driver supplying a data signal corresponding to a scan by the scan driver to the data electrode; And And a control unit for generating a gain control reference value for a plurality of consecutive frames and controlling gain according to the gain control reference value. The plasma display apparatus of claim 1, wherein the controller determines a switching level of each frame, and then generates a gain control reference value for a plurality of consecutive frames. The plasma display apparatus of claim 1, wherein the control unit maintains a current gain value when the gain value exceeds a predetermined maximum value or is less than a predetermined minimum value. The switching count according to claim 1, wherein the control unit performs switching counts according to values of adjacent cells belonging to m-1 rows, n columns and m rows, and n-1 columns in the case of cells belonging to m rows and n columns (m and n are natural numbers). Plasma display device, characterized in that for calculating. The plasma display apparatus of claim 4, wherein the controller calculates a switching count as 0 when the value of each cell and the value of the neighboring cell are the same, and as 1 when the remaining values are the same. The plasma display apparatus of claim 2, wherein the controller determines a switching level by setting a value obtained by multiplying the switching count values of all cells and the number of subfields to a maximum value. The plasma display apparatus of claim 2, wherein the controller determines a switching level by setting 0 to a minimum value. The plasma display apparatus of claim 2, wherein the controller sets a switching level by setting a threshold region between a maximum value and a minimum value. The method of claim 2, wherein the control unit sets the switching level by dividing the first section between the maximum value and the threshold region, the second section that is the threshold region section, and the third section between the threshold region and the minimum value region. Plasma display device. The plasma display apparatus of claim 2, wherein the controller sets a switching level by allocating a predetermined value to the first, second, and third sections. The plasma display apparatus of claim 2, wherein the controller generates a gain control reference value by summing switching levels of a plurality of consecutive frames. 12. The plasma display apparatus of claim 11, wherein the controller controls the gain to increase or decrease by a value determined according to the gain control reference value. Calculating a switching count for each cell unit; Setting a switching level of each frame; Generating a gain control reference value for a plurality of consecutive frames; And And controlling the gain according to the sum of the switching levels. 15. The method of driving a plasma display panel according to claim 13, further comprising maintaining a current gain value when the gain value exceeds a predetermined maximum value or is below a predetermined minimum value. The method of claim 13, wherein the calculating of the switching count in each cell unit comprises: m-1 rows, n columns and m rows, and n-1 columns for cells belonging to m rows, n columns (m, n is a natural number). And a switching count is calculated according to a value of an adjacent cell belonging to the plasma display panel. 16. The method of claim 15, wherein the switching count is calculated as 0 when the value of each cell and the value of the neighboring cell are the same, and as 1 when the remaining cells are the same. The driving of the plasma display panel of claim 13, wherein the setting of the switching level of each frame comprises setting the switching level by setting a value obtained by multiplying the switching count values of all cells and the number of subfields to a maximum value. Way. The method of claim 13, wherein the setting of the switching level of each frame comprises setting the switching level by setting 0 to a minimum value. The method of claim 13, wherein the setting of the switching level of each frame comprises setting a switching level by setting a threshold region between a maximum value and a minimum value. 20. The method of claim 19, wherein the switching level is set between a maximum value and a minimum value as a first period between a maximum value and a threshold value area, a second period that is a threshold value area, and a third period between a threshold value area and a minimum value area. And a switching level is set by dividingly setting. 21. The method of claim 20, wherein the setting of the switching level is to set a switching level by allocating a predetermined value to the first, second, and third sections. The method of claim 13, wherein the generating of the gain control reference value comprises generating a gain control reference value by summing switching levels of a plurality of consecutive frames. The method of claim 13, wherein the controlling of the gain is performed such that the gain increases or decreases by a value determined according to the gain control reference value.

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