KR100976974B1 - A luminance difference compensating circuit and passive matrix organic light emitting diode panel driving system including the circuit - Google Patents

Abstract

The present invention discloses a luminance difference correction circuit, a correction method, and a passive matrix organic light emitting diode panel driving system including the correction circuit which can be applied regardless of the RGB pattern. The luminance difference correction circuit includes an R pattern analysis circuit, a G pattern analysis circuit, a G pattern analysis circuit, and an RGB pattern analysis circuit. The R pattern analysis circuit analyzes a plurality of R patterns according to the R first reference value R second reference value and R control signal to generate an R pattern analysis value and an R current signal. The G pattern analysis circuit generates a G pattern analysis value and a G current signal by analyzing a plurality of G patterns according to the G second reference value, the G second reference value, and the G control signal. The B pattern analysis circuit generates a B pattern analysis value and a B current signal by analyzing a plurality of B patterns according to the B first reference value, the B second reference value, and the B control signal. The RGB pattern analysis circuit is configured to output the R control signal, the G control signal, and the B control signal in response to an RGB first reference value, an RGB second reference value, the R pattern analysis value, the G pattern analysis value, and the B pattern analysis value. And generate a reference current control signal.

Luminance difference, correction circuit, passive matrix, organic light emitting diode

Description

A luminance difference compensating circuit and passive matrix organic light emitting diode panel driving system including the circuit}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a luminance difference correction circuit, and in particular, a cross talk generated according to a pattern of an image signal reproduced in a display panel implemented with a passive matrix organic light emitting diode (PMOLED). And a passive matrix organic light emitting diode panel driving system having the luminance difference correction circuit for correcting the difference.

Organic light emitting diodes (OLEDs) self-emit organic matters emitting red, green, and blue light formed on organic substrates, and their electrical characteristics are similar to those of diodes.

The organic light emitting diode is composed of an organic layer, a cathode and an anode, and electrons and holes injected through the cathode and the anode are recombined in the organic thin film, and the excitons generated at this time are generated. Is used to emit light of a specific wavelength while being reduced to the ground state. The display formed of the organic light emitting diode does not have a viewing angle, has excellent visibility, and does not use liquid crystal, and thus has a low power consumption in addition to the fast response speed. In addition, since the backlight does not require a self-luminous, it can be manufactured in a light and thin form.

The organic light emitting diode is classified into a passive matrix organic light emitting diode and an active matrix organic light emitting diode. In the case of implementing a display using an organic light emitting diode, a passive matrix organic light emitting diode is suitable for a line driving method in which an entire line emits light simultaneously, whereas an active matrix organic light emitting diode is suitable for an individual driving method which emits light individually. Among them, passive matrix organic light emitting diodes are disadvantageous for implementing large-area displays because of their high power consumption, but they are suitable for small display panels such as wireless cellular phones because of their simple manufacturing process and low manufacturing cost.

In a panel implemented with a passive matrix organic light emitting diode, a luminance difference occurs in a specific portion of the panel according to a pattern of a video signal to be reproduced. This is called cross talk.

1 illustrates a crosstalk noise phenomenon of a display panel implemented with a passive matrix organic light emitting diode.

Referring to the left figure of FIG. 1, when a square black pattern is implemented between white pattern lines, a black pattern between white pattern lines and a square The patterns on the left and right sides of the (black pattern) appear brighter than the pattern in which they are all white, in which case a luminance difference occurs in this area.

Referring to the right drawing of FIG. 1, when a square black pattern is implemented between red pattern lines, the black between the red pattern lines and the square black pattern is implemented. The patterns on the left and right sides of the black pattern appear brighter red than the whole red pattern, in which case a luminance difference occurs in this region.

The left figure of FIG. 1 is for a uniform pattern of white, that is, RGB (Red, Green, Blue), while the right figure is for a pattern in which red is emphasized.

The conventional method of compensating for such a difference in luminance occurs by separately analyzing each pattern of input RGB data, and then comparing the amount of current supplied from the current generation circuit used to implement each color to each horizontal line ( row line).

2 is a block diagram of a panel drive system including a conventional luminance difference correction circuit.

Referring to FIG. 2, the conventional panel driving system 200 includes a reference current generating circuit 210, a luminance difference correction circuit 220, a horizontal line driving circuit 230, a vertical line driving circuit 240, and a panel ( 250).

The luminance difference correction circuit 220 includes three analysis circuits 221 to 223 and three current generation circuits 224 to 226. The three analysis circuits 221 to 223 analyze the three red row patterns, the green row patterns, and the blue row patterns, respectively. Generate current reference signals R_Ref, G_Ref, and B_Ref. The three current generation circuits 224 to 226 may respond to the three currents R_I in response to the corresponding signals among the reference current I_Ref and the three current reference signals R_Ref, G_Ref, and B_Ref generated from the reference current generation circuit 210. , G_I, B_I).

The horizontal line driving circuit 230 drives the panel by one horizontal line unit using three currents R_I, G_I, and B_I. The vertical line driver circuit 240 drives the vertical line of the panel 250.

As described above, the conventional luminance difference correction circuit for compensating the luminance difference can be distinguished when the luminance difference occurs in a pattern in which a specific color is highlighted among RGB and when the luminance difference occurs in a uniform white pattern of RGB. Since no means or method is applied, a correction circuit suitable for one pattern includes a disadvantage that crosstalk noise is generated when applied to another pattern as it is.

The technical problem to be solved by the present invention is to provide a luminance difference correction circuit that can be applied regardless of the RGB pattern.

Another technical problem to be solved by the present invention is to provide a passive matrix organic light emitting diode panel driving system that can be applied regardless of the RGB pattern.

Another technical problem to be solved by the present invention is to provide a luminance difference correction method that can be applied regardless of the RGB pattern.

The luminance difference correction circuit according to the present invention for achieving the above technical problem includes an R pattern analysis circuit, a G pattern analysis circuit, a G pattern analysis circuit, and an RGB pattern analysis circuit. The R pattern analysis circuit analyzes a plurality of R patterns according to the R first reference value R second reference value and R control signal to generate an R pattern analysis value and an R current signal. The G pattern analysis circuit generates a G pattern analysis value and a G current signal by analyzing a plurality of G patterns according to the G second reference value, the G second reference value, and the G control signal. The B pattern analysis circuit generates a B pattern analysis value and a B current signal by analyzing a plurality of B patterns according to the B first reference value, the B second reference value, and the B control signal. The RGB pattern analysis circuit is configured to output the R control signal, the G control signal, and the B control signal in response to an RGB first reference value, an RGB second reference value, the R pattern analysis value, the G pattern analysis value, and the B pattern analysis value. And generate a reference current control signal.

The passive matrix organic light emitting diode panel driving system according to the present invention for achieving the above technical problem includes a luminance difference correction circuit and an RGB current generation circuit. The luminance difference correction circuit generates a reference current, an R current signal, a G current signal, and a B current signal in response to a plurality of R patterns, a plurality of G patterns, a plurality of B patterns, and a plurality of reference signals. The RGB current generation circuit generates R current, G current and B current in response to the reference current, the R current signal, the G current signal, and the B current signal.

According to another aspect of the present invention, there is provided a method for compensating a luminance difference, wherein a reference current, an R current, and a G current are generated in response to a plurality of R patterns, a plurality of G patterns, a plurality of B patterns, and a plurality of reference signals. And a luminance difference correction method for generating a B current, in order to correct a crosstalk noise generated in a pattern in which a specific color is emphasized, the amount of the R current, the G current, and the B current is adjusted, and the crosstalk generated in a uniform pattern is generated. To correct the noise, the amount of the reference current is adjusted.

According to another aspect of the present invention, a luminance difference correcting method includes a plurality of R patterns, a plurality of G patterns), a plurality of B patterns, and a plurality of reference signals in response to a reference current, an R current, A luminance difference correction method for generating a G current and a B current, the R current, the G current, and the B current for correcting a crosstalk noise occurring in a pattern in which a specific color is emphasized and correcting a crosstalk noise occurring in a uniform pattern. The amount of reference is controlled simultaneously with the amount of.

The present invention has the advantage that it is possible to correct the luminance difference that can be applied regardless of the RGB pattern.

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

3 is a block diagram of a passive matrix organic light emitting diode panel driving system according to the present invention.

Referring to FIG. 3, the passive matrix organic light emitting diode panel driving system 300 includes a luminance difference correction circuit 310, an RGB current generation circuit 320, a horizontal line driving circuit 330, a vertical line driving circuit 340, and the like. A passive matrix organic light emitting diode panel 350 is provided.

The luminance difference correction circuit 310 responds to the reference currents I_Ref and the plurality of reference values Ref_ *, the plurality of R patterns R_RPD, the plurality of G patterns G_RPD, and the plurality of B patterns B_RPD. R pattern analysis circuit 311, G pattern analysis circuit 312, B pattern analysis circuit 313, RGB pattern analysis circuit 314 and reference current generation circuit which generate four current signals R_Ref, G_Ref and B_Ref. 315.

The R pattern analysis circuit 311 analyzes the plurality of R patterns R_RPD according to the R first reference value Ref_R1, the R second reference value Ref_R2, and the R control signal C_R, thereby analyzing the R pattern analysis value R_Count and The R current signal R_Ref is generated.

The G pattern analysis circuit 312 analyzes the plurality of G patterns G_RPD according to the G first reference value Ref_G1, the G second reference value Ref_G2, and the G control signal C_G, thereby analyzing the G pattern analysis values G_Count and The G current signal G_Ref is generated.

The B pattern analysis circuit 313 analyzes a plurality of B patterns B_RPD according to the B first reference value Ref_B1, the B second reference value Ref_B2, and the B control signal C_B, thereby analyzing the B pattern analysis value B_Count. And a B current signal B_Ref.

The RGB pattern analysis circuit 314 responds to the RGB first reference value Ref_RGB1, the RGB second reference value Ref_RGB2, the R pattern analysis value R_Count, the G pattern analysis value G_Count, and the B pattern analysis value B_Count. The R control signal C_R, the G control signal C_G, the B control signal C_B and the reference current control signal REF_CTRL are generated. The reference current generation circuit 315 generates the reference current I_Ref in response to the reference current control signal REF_CTRL.

The R pattern analysis circuit 311, the G pattern analysis circuit 312, the B pattern analysis circuit 313, and the RGB pattern analysis circuit 314 will be described in more detail with reference to FIGS. 4 to 7.

The RGB current generation circuit 320 generates a plurality of currents R_I, G_I, and B_I in response to the reference current I_Ref and the plurality of current signals R_Ref, G_Ref, and B_Ref. The horizontal line driving circuit 330 drives the horizontal line of the passive matrix organic light emitting diode panel 350 in response to the plurality of currents R_I, G_I, and B_I. The vertical line driving circuit 340 drives the vertical line of the passive matrix organic light emitting diode panel 350.

FIG. 4 is a block diagram of an R pattern analysis circuit shown in FIG. 3.

Referring to FIG. 4, the R pattern analysis circuit 311 includes an adder 410, a comparator 420, a counter 430, and a control circuit 440.

The adder 410 generates the R pattern addition signal SUM_R by adding the plurality of R patterns R_RPD. The comparator 420 generates an R pattern comparison signal COM_R by comparing the R pattern addition signal SUM_R with the R first reference value Ref_R1. The counter 430 counts the R pattern comparison signal COM_R and generates an R pattern analysis value R_Count. The control circuit 440 generates an R current signal R_Ref in response to the R pattern analysis value R_Count and the R control signal C_R, and generates the R second reference value Ref_R2 when generating the R current signal R_Ref. It is also possible to consider more.

Here, the R first reference value Ref_R1 is used in the same concept that the R pattern addition signal SUM_R is the threshold value at which crosstalk noise occurs in the panel, and must be set in advance before the circuit operates. The R first reference value Ref_R1 will be determined according to the panel driving system used.

The R second reference value Ref_R2 is used to determine the value of the R current signal R_RF generated by the control circuit 440 and must be set in advance before the circuit operates.

As a result of analyzing a plurality of R patterns R_RPD, a plurality of G patterns G_RPD, and a plurality of B patterns B_RPD, the R control signal C_R includes a pattern in which a specific color is highlighted among RGB. The signal is selectively outputted from the RGB pattern analysis circuit 314 as it is and the value of which is selectively changed depending on the case where RGB contains a uniform white pattern.

FIG. 5 is a block diagram of the G pattern analysis circuit shown in FIG. 3.

Referring to FIG. 5, the G pattern analysis circuit 312 includes an adder 510, a comparator 520, a counter 530, and a control circuit 540.

The adder 510 generates the G pattern addition signal SUM_G by adding the plurality of G patterns G_RPD. The comparator 520 generates a G pattern comparison signal COM_G by comparing the G pattern addition signal SUM_G with the G first reference value Ref_G1. The counter 530 counts the G pattern comparison signal COM_G and generates a G pattern analysis value G_Count. The control circuit 540 generates the G current signal G_Ref in response to the G pattern analysis value g_Count and the G control signal C_G, and generates the G second reference value Ref_G2 when generating the G current signal G_Ref. It is also possible to consider more.

Here, the G first reference value Ref_G1, the G control signal C_G, and the G second reference value Ref_G2 are for the green image data, and are easily explained from the description of the R pattern analysis circuit 311 for the red image data. Can be inferred.

FIG. 6 is a block diagram of the B pattern analysis circuit shown in FIG. 3.

Referring to FIG. 6, the G pattern analysis circuit 313 includes an adder 610, a comparator 620, a counter 630, and a control circuit 640.

The adder 610 adds the plurality of B patterns B_RPD to generate the B pattern addition signal SUM_B. The comparator 620 generates the B pattern comparison signal COM_B by comparing the B pattern addition signal SUM_B and the B first reference value Ref_B1. The counter 630 counts the B pattern comparison signal COM_B to generate a B pattern analysis value B_Count. The control circuit 640 generates the B current signal B_Ref in response to the B pattern analysis value B_Count and the B control signal C_B, and generates the B second reference value Ref_B2 when generating the B current signal B_Ref. It is also possible to consider more.

Here, the B first reference value Ref_B1, the B control signal C_B, and the B second reference value Ref_B2 are for the blue image data, and are easily explained from the description of the R pattern analysis circuit 311 for the red image data. Can be inferred.

FIG. 7 is a block diagram of the RGB pattern analysis circuit of FIG. 3.

Referring to FIG. 7, the RGB pattern analysis circuit 314 includes a comparator 710 and a control circuit 720.

 The comparator 710 responds to the RGB first reference value Ref_RGB1, the R pattern analysis value R_Count, the G pattern analysis value G_Count, and the B pattern analysis value B_Count in response to the R control signal C_R and G control signal ( C_G), B control signal C_B and RGB total pattern analysis value RGB_TD. The control circuit 720 generates the reference current control signal REF_CTRL in response to the R control signal C_R, the G control signal C_G, the B control signal C_B, and the RGB total pattern analysis value RGB_TD. In accordance with this, the RGB second reference value Ref_RGB2 may be further considered.

Here, the RGB first reference value Ref_RGB1 is compared with the R pattern analysis value R_Count, the G pattern analysis value G_Count, and the B pattern analysis value B_Count, so that the input image signal includes a pattern in which a specific color is highlighted among RGB. Is a reference value to determine the case of the current condition and the case where RGB contains a uniform white pattern and should be set in advance before the circuit operates.

The RGB total pattern analysis value RGB_TD is a total value of the R pattern analysis value R_Count, the G pattern analysis value G_Count, and the B pattern analysis value B_Count.

The RGB second reference value Ref_RGB2 is used to determine the value of the reference current control signal REF_CTRL generated by the control circuit 720 and must be set in advance before the circuit operates.

The luminance value correction circuit according to the present invention adjusts the amounts of R current (R_I), G current (G_I), and B current (B_I) in order to correct crosstalk noise occurring in a pattern in which a specific color is emphasized. To correct the crosstalk noise generated, the amount of reference current I_Ref is adjusted. Although not described here, the amount of R current (R_I), G current (G_I), and B current (B_I) is used to correct crosstalk noise occurring in a pattern in which a specific color is emphasized, and to correct crosstalk noise occurring in a uniform pattern. It is also possible to adjust the amount of reference current I_Ref at the same time.

First, a method of correcting crosstalk noise occurring in a pattern in which a specific color is highlighted will be described.

Three pattern addition signals SUM_R, SUM_G, and SUM_B are calculated by adding the image data of the corresponding color to the plurality of image data corresponding to one horizontal line 1Row by three pattern analysis circuits 311 to 313, respectively. The pattern analysis value determined by counting the number of data larger than the reference value (Ref_R1, Ref_G1, Ref_B1) by comparing the three pattern addition signals SUM_R, SUM_G, and SUM_B with three corresponding reference values (Ref_R1, Ref_G1, Ref_B1). (R_Count, G_Count, B_Count) is transmitted to the RGB pattern analysis circuit 314. The RGB pattern analysis circuit 314 compares the respective pattern analysis values (R_Count, G_Count, B_Count) and the RGB reference values (Ref_RGB1). By adjusting the control signals C_R, C_G, and C_B, the amount of R current (R_I), G current (G_I), and B current (B_I) used to implement the corresponding color can be adjusted so that Correct crosstalk noise.

Hereinafter, a method of correcting crosstalk noise occurring in a uniform pattern will be described.

Three pattern addition signals SUM_R, SUM_G and SUM_B are calculated by adding the image data of the corresponding color to the image data corresponding to one horizontal line (1Row) in three pattern analysis circuits 311 to 313, respectively. Pattern addition signals SUM_R, SUM_G, and SUM_B are compared with preset reference values Ref_R1, Ref_G1, and Ref_B1, and the pattern analysis value R_Count and G_Count determined by counting the number of data smaller than the reference values Ref_R1, Ref_G1, and Ref_B1. , B_Count) is transmitted to the RGB pattern analysis circuit 314.

If the difference between the three pattern analysis values R_Count, G_Count, and B_Count in the RGB pattern analysis circuit 314 is smaller than the RGB first reference value Ref_RGB1, the control circuit 720 may determine the RGB second reference value Ref_RGB2. The output value of the reference current control signal REF_CTRL is determined by comparing the RGB total pattern analysis value RGB_TD. The reference current I_Ref is increased or decreased by the value assigned to the reference current control signal REF_CTRL. Since the R current R_I, the G current G_I, and the B current B_I are increased or decreased at the same ratio, It is possible to correct the crosstalk noise generated by this.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope of the present invention.

1 illustrates a crosstalk noise phenomenon of a display panel implemented with a passive matrix organic light emitting diode.

2 is a block diagram of a panel drive system including a conventional luminance difference correction circuit.

3 is a block diagram of a passive matrix organic light emitting diode panel driving system according to the present invention.

FIG. 4 is a block diagram of an R pattern analysis circuit shown in FIG. 3.

FIG. 5 is a block diagram of the G pattern analysis circuit shown in FIG. 3.

FIG. 6 is a block diagram of the B pattern analysis circuit shown in FIG. 3.

FIG. 7 is a block diagram of the RGB pattern analysis circuit of FIG. 3.

Claims (9)

 R first reference value Ref_R1, which is the limit value at which the crosstalk noise occurs on the panel, R second reference value Ref_R2, which is the reference value for the R current signal R_Ref, and the R control signal ( An R pattern analysis circuit 311 analyzing the plurality of R patterns R_RPD according to C_R to generate an R pattern analysis value R_Count and the R current signal R_Ref; The G first reference value Ref_G1, which is the threshold value at which the crosstalk noise is generated on the panel, and the G second reference value Ref_G2, which is the reference value for the G current signal G_Ref, and the G control signal ( A G pattern analysis circuit 312 for analyzing a plurality of G patterns G_RPD according to C_G to generate a G pattern analysis value G_Count and the G current signal G_Ref; The first B reference value Ref_B1, which is the threshold value at which the crosstalk noise occurs on the panel, and the second B reference value Ref_B2, which is the reference value for the B current signal B_Ref, and the B control signal ( A B pattern analysis circuit 313 for analyzing a plurality of B patterns B_RPD according to C_B to generate a B pattern analysis value B_Count and the B current signal B_Ref; And The R control signal in response to the RGB first reference value Ref_RGB1, the RGB second reference value Ref_RGB2, the R pattern analysis value R_Count, the G pattern analysis value G_Count, and the B pattern analysis value B_Count. And an RGB pattern analysis circuit (314) for generating the C_R, the G control signal (C_G), the B control signal (C_B), and the reference current control signal (REF_CTRL). The method of claim 1, And a reference current generating circuit (315) for generating a reference current (I_Ref) in response to the reference current control signal (REF_CTRL). The method of claim 1, wherein the R pattern analysis circuit 311, An adder 410 for generating an R pattern addition signal SUM_R by adding the plurality of R patterns R_RPD; A comparator (420) for generating an R pattern comparison signal (COM_R) by comparing the R pattern addition signal (SUM_R) with the R first reference value (Ref_R1); A counter 430 for counting the R pattern comparison signal COM_R and generating the R pattern analysis value R_Count; And And a control circuit 440 for generating the R current signal R_Ref in response to the R pattern analysis value R_Count, the R second reference value Ref_R2, and the R control signal C_R. Luminance difference correction circuit. The method of claim 1, wherein the G pattern analysis circuit 312, An adder 510 for generating a G pattern addition signal SUM_G by adding the plurality of G patterns G_RPD; A comparator (520) for generating a G pattern comparison signal (COM_G) by comparing the G pattern addition signal (SUM_G) with the G first reference value (Ref_G1); A counter 530 for counting the G pattern comparison signal COM_G and generating the G pattern analysis value G_Count; And And a control circuit 540 for generating the G current signal G_Ref in response to the G pattern analysis value G_Count, the G second reference value Ref_G2, and the G control signal C_G. Luminance difference correction circuit. The method of claim 1, wherein the B pattern analysis circuit 313, An adder 610 for generating a B pattern addition signal SUM_B by adding the plurality of B patterns B_RPD; A comparator (620) for generating a B pattern comparison signal (COM_B) by comparing the B pattern addition signal (SUM_B) with the B first reference value (Ref_B1); A counter 630 for counting the B pattern comparison signal COM_B and generating the B pattern analysis value B_Count; And And a control circuit 640 for generating the B current signal B_Ref in response to the B pattern analysis value B_Count, the B second reference value Ref_B2, and the B control signal C_B. Luminance difference correction circuit. The method of claim 1, wherein the RGB pattern analysis circuit 314, The R control signal (C_R) and the G control signal in response to the RGB first reference value (Ref_RGB1), the R pattern analysis value (R_Count), the G pattern analysis value (G_Count), and the B pattern analysis value (B_Count). A comparator 710 for generating a C_G, the B control signal C_B, and an RGB total pattern analysis value RGB_TD; And The reference current control signal in response to the R control signal C_R, the G control signal C_G, the B control signal C_B, the RGB total pattern analysis value RGB_TD, and the RGB second reference value Ref_RGB2. And a control circuit 720 for generating REF_CTRL. In response to a plurality of R patterns R_RPD, a plurality of G patterns G_RPD, a plurality of B patterns B_RPD, and a plurality of reference signals Ref_ *, a reference current I_Ref, an R current signal R_Ref, and a G current A luminance difference correction circuit 310 for generating a signal G_Ref and a B current signal B_Ref; And R current R_I, G current G_I, and B current B_I in response to the reference current I_Ref, the R current signal R_Ref, the G current signal G_Ref, and the B current signal B_Ref. Passive matrix organic light emitting diode panel drive system, characterized in that it comprises a RGB current generation circuit (320) for generating a. In response to the plurality of R patterns R_RPD, the plurality of G patterns G_RPD, the plurality of B patterns B_RPD, and the plurality of reference signals Ref_ *, the reference current I_Ref, R current R_I, and G current ( In the luminance difference correction method for generating G_I) and B current (B_I), To correct the crosstalk noise generated in a pattern in which a specific color is emphasized, the amount of the R current (R_I), the G current (G_I), and the B current (B_I) is adjusted, and the crosstalk noise generated in a uniform pattern is corrected. In order to adjust the luminance difference, characterized in that for adjusting the amount of the reference current (I_Ref). In response to the plurality of R patterns R_RPD, the plurality of G patterns G_RPD, the plurality of B patterns B_RPD, and the plurality of reference signals Ref_ *, the reference current I_Ref, R current R_I, and G current ( In the luminance difference correction method for generating G_I) and B current (B_I), The R current (R_I), the G current (G_I), the B current (B_I), and the reference current (C) for the correction of the crosstalk noise generated in a pattern in which a specific color is emphasized and the correction of the crosstalk noise generated in a uniform pattern. Adjusting the amount of I_Ref).

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