KR20150037423A - Method and apparatus controlling peak luminance of organic light emitting diode display device - Google Patents

Abstract

The present invention relates to a method and a device for controlling peak luminance of an OLED display device which can reduce power consumption by controlling peak luminance according to various image characteristics. The method for controlling peak luminance according to the present invention comprises: a first step of detecting APL from an input image; a second step of setting at least two different peak luminance according to the APL; a third step of extracting at least one image characteristic information among edge information and histogram distribution information from the input image and generating a weight representing the complexity of the corresponding image using the extracted image characteristic information; and a fourth step of outputting final peak luminance by selecting one of the peak luminance using the weight or weighted averaging the peak luminance using the weight.

Description

TECHNICAL FIELD [0001] The present invention relates to an organic light emitting diode (OLED) display device, and more particularly,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting diode (OLED) display device, and more particularly, to a method and apparatus for controlling peak luminance of an OLED display device capable of controlling peak luminance according to various image characteristics.

The OLED display is a self-luminous device that emits an organic light-emitting layer by recombination of electrons and holes, and is expected to be a next-generation display device because of its high brightness, low driving voltage and ultra thin film.

Each of the plurality of pixels (sub-pixels) constituting the OLED display device includes an OLED element composed of an organic light emitting layer between the anode and the cathode, and a pixel circuit independently driving the OLED element. The pixel circuit includes at least a switching transistor and a storage capacitor and a driving transistor. The switching transistor charges the storage capacitor with a voltage corresponding to the data signal in response to the scan pulse, and the driving transistor controls the current supplied to the OLED element according to the voltage charged in the storage capacitor to adjust the amount of light emitted from the OLED element. The amount of light emission of the OLED is proportional to the current supplied from the driving transistor.

In order to reduce the power consumption, the conventional OLED display device controls the current through the peak luminance control, that is, controls the current of the display panel by adjusting the gamma voltage by controlling the peak luminance (maximum white luminance) And the like.

Conventional OLED display devices control the peak luminance using the average picture level (APL) or maximum data of each frame. For example, in conventional OLED display devices, the peak luminance is increased when the APL is low, and the power consumption is reduced by lowering the peak luminance when the APL is high.

However, the conventional OLED display device has limitations in terms of power consumption because it controls the peak luminance using only one reference (APL or maximum data) of various image characteristics.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a peak brightness control method and apparatus for an OLED display which can reduce power consumption by controlling peak brightness according to various image characteristics. .

According to an aspect of the present invention, there is provided a method of controlling peak brightness of an OLED display device, including: a first step of detecting an APL from an input image; A second step of setting at least two different peak luminances depending on the APL; A third step of extracting at least one image characteristic information from edge information and histogram distribution information from the input image and generating a weight indicating a complexity of the image using the extracted image characteristic information; And a fourth step of selecting one of the at least two peak luminances using the weight or weight-averaging the at least two peak luminances using the weight and outputting the final peak luminance.

An apparatus for controlling peak brightness of an OLED display according to the present invention includes: an APL detecting unit for detecting an APL from an input image; A peak brightness setting unit for setting at least two different peak brightnesses according to the APL; A weight generation unit for extracting at least one image characteristic information from edge information and histogram distribution information from the input image and generating a weight indicating a complexity of the image using the extracted image characteristic information; And a peak luminance adjusting unit for selecting one of the at least two peak luminance using the weight or weight-averaging the at least two peak luminance using the weight and outputting a final peak luminance.

Wherein the second step and the peak luminance setting unit use at least two lookup tables corresponding to at least two peak luminance curves different in peak luminance for all the APLs, Respectively.

The third step and the weight generation unit may include detecting edge counts from the input image, extracting the edge information, and generating an edge gain using the edge information; Generating and analyzing a histogram for each gradation from the input image, extracting the histogram distribution information indicating a distribution size of the histogram, and generating a histogram gain using the histogram distribution information; Multiplying the edge gain and the histogram gain by the weight value, and outputting either the edge gain or the histogram gain as the weight value.

The fourth step and the peak luminance adjusting unit use the following Equation (1) when weighting averaging the at least two peak luminance values using the weight values.

&Quot; (1) "

Pout = w x P1 + (1-w) x P2

Here, P1 and P2 are the peak luminance, w is the weight, and Pout is the final peak luminance.

The weight increases as the complexity of the image represented by at least one of the edge information and the histogram distribution information increases, and the final peak luminance decreases as the weight increases.

The method and apparatus for controlling the peak luminance of the OLED display according to the present invention can control the peak luminance by using at least one of the edge information and the histogram distribution information showing the image complexity in consideration of the luminance perception characteristics of the viewer as well as the APL, Can be maximized and the image quality can be improved.

1 is a graph showing the relationship between APL and peak luminance applied to the present invention and the relationship between APL and current consumption.
2 is a graph showing two peak luminance curves applied to the present invention.
3 is a block diagram showing a part of the configuration of the peak luminance control unit of the OLED display according to the first embodiment of the present invention.
4 is a graph showing a plurality of peak luminance curves used in the peak luminance setting unit shown in FIG.
5 is a block diagram showing a part of the configuration of the peak luminance control unit of the OLED display according to the second embodiment of the present invention.
6 is a graph showing a plurality of peak luminance curves used in the peak luminance setting unit shown in Fig.
7 is a block diagram illustrating a weight generator for applying the peak brightness controller according to the first and second embodiments of the present invention.
8 is a graph showing a histogram distribution used in the histogram distribution calculation unit shown in FIG.
FIG. 9 is a block diagram of a peak brightness control unit of an OLED display according to an exemplary embodiment of the present invention. Referring to FIG.
FIG. 10 is a block diagram of a peak brightness control unit of an OLED display according to a second embodiment of the present invention. Referring to FIG.
11 is a block diagram schematically illustrating an OLED display device to which a peak luminance controller according to an embodiment of the present invention is applied.
Fig. 12 is a flow chart for explaining the peak brightness control method of the peak brightness control section shown in Fig. 11 step by step.

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

1 is a graph showing the relationship between APL and peak luminance applied to the present invention and the relationship between APL and current consumption.

Since the correlation between the luminance and the current of the self-luminous element OLED is approximately linear, the total consumption current is proportional to the number of OLED pixels (luminous area) and luminance intensity emitted from the OLED display device. Since the emission area and luminance intensity can be expressed by APL, the consumption current is "APL × peak luminance".

Therefore, when the maximum consumption current is to be constant for reducing power consumption, the peak luminance is set so as to be in inverse proportion to the APL (peak luminance = k / APL; k is an arbitrary constant such as the peak luminance curve for APL shown in FIG. )do. That is, as the APL is larger (the bright image is), the peak brightness is lowered, and the smaller the APL (the darker the image), the higher the peak brightness.

As shown in FIG. 1 (a), when the peak luminance is set to be in inverse proportion to the APL, the current consumed in the OLED display device is higher than the peak luminance in the section where APL is relatively small, And when the APL exceeds a certain period, it becomes constant by the decrease of the peak luminance.

Referring to FIG. 1, it can be seen that the peak luminance curve for the APL shown in (a) must be changed when the consumption current is further reduced or the luminance upward for improving the image quality is required.

Therefore, in the present invention, the peak luminance curve is adaptively changed according to the recognition characteristics of the input image, thereby maximizing the reduction of the current consumption or improving the image quality.

For example, as shown in FIG. 2, the second peak luminance curve PLC2 is additionally set while maintaining the existing first peak luminance curve PLC1. In the second peak luminance curve (PLC2), the peak luminance is lower than that of the first peak luminance curve (PLC1) in order to reduce the consumption current in the section A where the APL is small, or the consumption current is slightly increased However, in order to improve the image quality, the peak luminance may be higher than the first peak luminance curve (PLC2).

  The first and second peak luminance curves PLC1 and PLC2 are selected according to the characteristic information of the input image.

Generally, if the number of edges in the image is large or the histogram distribution is wide, it can be regarded as a high-complexity image. Also, an image having a high complexity can be judged as an image having a high contrast ratio because a large number of edges, a high local contrast ratio, and a wide histogram distribution. Therefore, since a high-contrast image has a high contrast ratio, the degradation of the perceived image quality is small even when the peak luminance is reduced as compared with the conventional one.

Accordingly, in the present invention, one of the first and second peak luminance curves PLC1 and PLC2 can be selected using at least one of the image characteristic information of the edge information and the histogram distribution information extracted through the image analysis.

For example, in the case of a low-complexity image, the existing first peak luminance curve PLC1 is selected and the existing peak luminance is maintained, thereby not affecting the basic luminance specification of the display device. On the other hand, in an image having a high complexity such as a moving image, the added second peak luminance curve PLC2 is selected or the first and second peak luminance curves PLC1 and PLC2 are weighted averaged to reduce the peak luminance, can do. At this time, the number of peak luminance curves is not limited to two.

3 is a block diagram showing a part of a peak luminance control unit according to the first embodiment of the present invention.

The peak luminance control unit according to the first embodiment shown in FIG. 3 includes a peak luminance setting unit 112 and a multiplexer (hereinafter referred to as MUX) 114 which is a peak luminance selection unit.

4, the peak luminance setting section 112 includes a plurality of peak luminance curves (PLC1 to PLCn; n is an integer of 2 or more) set in advance and a plurality of peak luminance curves (PLC1 to PLCn) A plurality of peak intensities P1 to Pn corresponding to the APL are selected and output to set and output a plurality of peak intensities P1 to Pn according to the APL. The peak luminance setting unit 112 includes a plurality of look-up tables (LUTs) whose peak luminance according to the APL is set to be different from each other so as to correspond to the plurality of peak luminance curves PLC1 to PLCn shown in FIG. do. The peak luminance setting unit 112 selects and outputs a plurality of peak luminances P1 to Pn corresponding to APLs input from a plurality of LUTs to set and output a plurality of peak luminances P1 to Pn corresponding to the APLs .

The MUX 114 serving as a peak luminance selection unit selects one of the plurality of peak luminance P 1 to Pn supplied from the peak luminance setting unit 112 using the weight w determined in accordance with the image characteristic information indicating the image complexity The peak luminance is selected and output to the final peak luminance Pout. The weight w is generated using at least one of edge information and histogram dispersion information extracted through analysis of the input image. The larger the edge information, the wider the variance of the histogram, the more complex the image with higher contrast ratio, and the weight w which indicates the image complexity increases. As the weight w increases, the smaller peak luminance is selected for the higher-complexity image, and the smaller peak luminance is output as the final peak luminance Pout, thereby further reducing the power consumption. A specific method of generating the weight w will be described later.

5 is a block diagram showing a part of a peak luminance control unit according to a second embodiment of the present invention.

The peak luminance control unit according to the second embodiment shown in FIG. 5 includes a peak luminance setting unit 122 and a weighted average calculation unit 124 that is a peak luminance adjustment unit.

6, the peak luminance setting unit 122 includes two peak luminance curves PLC1 and PLC2 that are set in advance and two peaks corresponding to the APLs input from the two peak luminance curves PLC1 and PLC2, By selecting and outputting the luminances P1 and P2, two peak luminances P1 and P2 according to the APL are set and outputted. The peak luminance setting unit 122 includes two LUTs whose peak luminance according to the APL is set to be different from each other so as to correspond to the two peak luminance curves PLC1 and PLC2 shown in Fig. The peak luminance setting unit 122 selects and outputs two peak luminances P1 and P2 corresponding to APLs input from the two LUTs, thereby setting and outputting two peak luminances P1 and P2 according to the APL .

The weighted average calculation unit 124 that is the peak luminance adjustment unit uses the weight w determined in accordance with the image characteristic information indicating the image complexity to weight the two peak luminance values P1 and P2 supplied from the peak luminance setting unit 122 And outputs it as a final peak luminance on average. The weight w is generated using at least one of edge information and histogram dispersion information extracted through analysis of the input image. The weighted average calculator 124 outputs the final peak luminance Pout by weighting averaging the two peak intensities P1 and P2 determined according to the APL using the weight w as shown in Equation 1 below.

The weighted average calculator 124 determines the final peak luminance Pout by using the weighted average calculation using Equation 1 so that the final peak luminance Pout is obtained by using the two peak luminance curves PLC1 and PLC2 shown in FIG. Can be adaptively adjusted according to the weight (w). Accordingly, the higher the complexity of the image with the weight w increases, the smaller the final peak luminance, thereby further reducing the power consumption. A specific method of generating the weight w will be described later.

7 is a block diagram illustrating a weight generator for applying the peak brightness controller according to the first and second embodiments of the present invention.

The weight generation unit 160 shown in FIG. 7 includes an edge gain generation unit 130 for generating an edge gain according to the edge information extracted through the input image analysis, and a histogram distribution information extraction unit A histogram gain generating unit 146 for generating a histogram gain Hgain corresponding to the histogram gain Hgain and an arithmetic operation unit 150 for calculating the edge gain Eg and the histogram gain Hgain and outputting the result as a weight w.

The edge gain generator 130 includes an edge detector 132, an edge counter 134, and an edge gain calculator 136.

The edge detecting unit 132 scans an input image in at least one direction using a high pass filter (HPF) or a band pass filter (BPF) to detect a portion having a large luminance change amount as an edge, And extracts and outputs edge information indicating the edge.

The edge counter 134 counts the edge information supplied from the edge extracting unit 132 and outputs the edge information count number.

The edge gain calculator 136 calculates the edge gain Egain using the edge information count number supplied from the edge counter 134. [ The edge gain calculator 136 calculates an edge gain Egain proportional to or in inverse proportion to the edge information count number using a gain function predetermined by the designer. For example, the edge gain calculator 136 calculates a higher edge gain Egain as the number of counts of the edge information indicating the complexity of the image increases, and calculates the lower edge gain Egain as the count number of the edge information decreases have.

The histogram gain generation unit 140 includes a histogram generation unit 142, a histogram distribution calculation unit 144, and a histogram gain calculation unit 146.

The histogram generating unit 142 analyzes the input image and counts the frequency of each gradation to generate a histogram.

The histogram distribution calculation unit 144 arranges the histogram supplied from the histogram generation unit 142 for each gradation, digitizes the degree of distribution of the histogram, and outputs it as histogram distribution information. The histogram distribution calculation unit 144 arranges histograms in the order of increasing gradation as shown in Fig. The histogram distribution calculator 144 calculates a histogram average value of each frame and then calculates an absolute value (count-mean) of the difference between the counts of the gradation counts and the mean value as shown in Equation 2 below The histogram distribution (Histogram_distribution) can be quantified by summing the sum of absolute differences (SAD).

&Quot; (2) "

The histogram gain calculator 146 calculates the histogram gain Hgain using the histogram distribution information supplied from the histogram distribution calculator 144. [ The histogram gain calculator 146 calculates the histogram gain Hgain proportional to the histogram distribution information using a gain function preset by the designer. For example, the histogram gain calculator 146 may calculate a higher histogram gain Hgain as the histogram distribution representing the complexity of the image becomes wider, and a lower histogram gain Hgain as the histogram distribution becomes narrower.

The arithmetic unit 150 multiplies the edge gain Eggen supplied from the edge gain generator 130 by the histogram gain Hgain supplied from the histogram gain generator 140 and outputs the result as a weight w.

The edge gain generator 130 and the histogram gain generator 140 may selectively turn off the output of the edge gain Eg and the histogram gain Hgain in response to an external control signal including user selection . The edge gain generating unit 130 and the histogram gain generating unit 140 output the gain value of "1 " to the calculating unit 150 when the gain output is turned off by the external control signal.

When the output of the edge gain generator 130 is turned off by the external control signal, that is, when the gain value of "1" is input from the edge gain generator 130, the arithmetic unit 150 receives the gain value from the histogram gain generator 140 And outputs the histogram gain Hgain of the histogram as a weight w.

When the output of the histogram gain generator 140 is turned off by the external control signal, that is, when the gain value of "1" is inputted from the histogram gain generator 140, the arithmetic unit 150 receives the gain value from the edge gain generator 130 And outputs an edge gain (Egain) of the weighting factor w as a weight w.

When the outputs of the edge gain generator 130 and the histogram gain generator 140 are both turned off by the external control signal, the arithmetic unit 150 outputs a meaningless "1" as the weight w.

Alternatively, the weight generating unit 160 may include only the edge gain generating unit 130 and may output the edge gain Eg as a weight w or may include only the histogram gain generating unit 140 to obtain the histogram gain Hgain And output it as a weight w.

FIG. 9 is a block diagram of a peak brightness control unit of an OLED display according to an exemplary embodiment of the present invention. Referring to FIG.

The peak luminance controller 100 of the first embodiment shown in FIG. 9 includes an APL detector 110, a peak luminance setting unit 112, a MUX 114 as a peak luminance selector, and a weight generator 160. The peak luminance controller 100 further includes a luminance-voltage converter 116 and a digital-to-analog converter (DAC) 118.

The APL detecting unit 110 detects and outputs an APL indicating the number of pixels having a peak luminance in each frame of the input image, that is, an area occupied by white pixels in one screen.

The peak luminance setting unit 112 has a plurality of LUTs corresponding to a plurality of peak luminance curves PLC1 to PLCn, respectively, and having different peak luminance according to the APL. The peak luminance setting unit 112 selects and outputs a plurality of peak intensities P1 to Pn corresponding to the APLs supplied from the APL detecting unit 110 in a plurality of LUTs to generate a plurality of peak intensities P1 to Pn ) And outputs it. For power consumption control, the peak luminance in each peak luminance curve is determined to have an inverse relationship with APL. That is, the peak luminance is set to be lower as the APL is larger (the bright image is), and the peak luminance is set higher as the APL is lower (darker image).

The MUX 114 serving as the peak luminance selection unit uses the weight w determined in accordance with the image characteristic information indicating the image complexity in the weight generation unit 160 to generate a plurality of peak luminance P1 To Pn, and outputs the selected peak luminance to the final peak luminance Pout.

The weight generation unit 160 generates a weight w indicating the complexity of the image using at least one of the edge information and the histogram dispersion information extracted through the input image analysis and supplies the weight w to the MUX 114 .

The weight generation unit 160 includes an edge gain generation unit 130 for generating an edge gain according to the edge information extracted through the input image analysis as described above with reference to FIG. 7, a histogram generation unit 130 for generating a histogram A histogram gain generating unit 146 for generating a histogram gain Hgain in accordance with the dispersion information and an operation unit 150 for calculating the edge gain and the histogram gain Hgain and outputting the result as the weight w.

The weight generation unit 160 may not affect the weight w by turning off the output of at least one of the edge gain generation unit 130 and the histogram gain generation unit 140 in response to the external control signal.

Alternatively, the weight generating unit 160 may include only the edge gain generating unit 130 and may output the edge gain Eg as a weight w or may include only the histogram gain generating unit 140 to obtain the histogram gain Hgain And output it as a weight w.

The larger the edge information, the wider the variance of the histogram, the more complex the image with higher contrast ratio. Therefore, as the edge information increases, the edge gain Eg increases, and as the histogram dispersion degree becomes wider, the histogram gain Hgain increases, and the weight w indicating the image complexity increases.

The MUX 114 selects a small peak luminance as the weight w supplied from the weight generation unit 160 increases, that is, the image having a higher complexity (or contrast ratio), and outputs the smaller peak luminance as the final peak luminance Pout Thereby further reducing power consumption. At this time, as the APL increases, the final peak luminance may be slightly increased compared to the case where only the conventional APL is used. However, in this case, the luminance may be improved and the image quality may be improved.

The luminance-voltage converter 116 converts the final peak luminance Pout supplied from the MUX 114 into a corresponding gamma high-potential voltage and outputs the converted voltage. The luminance-voltage conversion unit 116 has a LUT in which the corresponding gamma high potential voltage is preset according to the final peak luminance Pout. The luminance-voltage converter 116 selects and outputs the gamma high potential voltage corresponding to the final peak luminance Pout in the LUT.

The DAC 118 converts the gamma high voltage supplied from the brightness-voltage converter 116 into the analog voltage MVDD and supplies the analog voltage MVDD to the high potential power supply of the gamma voltage generator.

FIG. 10 is a block diagram of a peak brightness control unit of an OLED display according to a second embodiment of the present invention. Referring to FIG.

The peak luminance controller 200 of the second embodiment shown in FIG. 10 is different from the peak luminance controller 100 of the first embodiment shown in FIG. 9 in that the peak luminance controller 122 and the weighted average calculator 124 Are distinguished from the peak brightness setting unit 112 and the MUX 114 of the first embodiment, and the remaining configurations are the same, so the description of the overlapping configurations will be omitted or omitted.

Referring to FIG. 10, the peak luminance setting unit 122 includes two LUTs whose peak luminance according to the APL is set to be different from each other so as to correspond to the two peak luminance curves PLC1 and PLC2, respectively. The peak luminance setting section 122 selects and outputs two peak luminance values P1 and P2 corresponding to the APL supplied from the APL detecting section 110 in the two LUTs to obtain two peak luminance values P1 and P2 ) And outputs it.

The weighted average calculation unit 124 that is the peak luminance adjustment unit uses the weight w determined in accordance with the image characteristic information indicating the image complexity to weight the two peak luminance values P1 and P2 supplied from the peak luminance setting unit 122 And the average is output as the final peak luminance Pout.

The weight generation unit 160 generates a weight w indicating the complexity of the image using at least one of the edge information and the histogram dispersion information extracted through the input image analysis and outputs the weight w to the weighted average operation unit 124 Supply.

The weighted average calculator 124 outputs the final peak luminance Pout by weighted average calculation using the weight w using the two peak intensities P1 and P2 determined according to the APL as described above. Accordingly, the weighted average calculator 124 can further reduce the power consumption by reducing the final peak luminance Pout as the image having a high complexity in which the weight w increases.

The final peak luminance Pout output from the weighted average calculator 124 is converted to a corresponding gamma high potential voltage MVDD through the brightness-to-voltage converter 116 and the DAC 118, .

11 is a block diagram schematically illustrating an OLED display device to which a peak luminance controller according to an embodiment of the present invention is applied.

1 includes a timing controller 10, a data driver 20, a gate driver 30, a gamma voltage generator 40 and a display panel 50. The OLED display includes a timing controller 10, And a peak luminance control unit 60 connected between the voltage generating units 40.

The timing controller 10 generates a data control signal and a gate control signal for controlling the driving timings of the data driver 20 and the gate driver 30 using a plurality of synchronous signals inputted from the outside, And the timing of driving the gate driver 30. The timing controller 10 modulates the input image through various data modulation methods for improving image quality and outputs the modulated input image to the data driver 20. [

The peak luminance controller 60 determines the peak luminance according to the characteristics of the image supplied from the timing controller 10, adjusts the gamma high potential voltage according to the determined peak luminance, and outputs the adjusted gamma high potential voltage MVDD to the gamma voltage generation (40). The peak luminance control unit 100 of the first embodiment described above with reference to FIG. 9 is applied to the peak luminance control unit 60, or the peak luminance control unit 200 of the second embodiment described above with reference to FIG. 10 is applied.

The peak luminance controller 60 analyzes the input image frame by frame and determines the final peak luminance using at least two pieces of information, i.e., the APL, the edge information, and the histogram dispersion information.

Referring to FIG. 12, the peak luminance controller 60 detects an APL by analyzing an input image (S2), and selects at least two peak luminances based on the APL in at least two preset peak luminance curves, At least two peak luminances are set (S4). At the same time, the peak luminance controller 60 generates a weight indicating image complexity using at least one of the edge information and the histogram dispersion information extracted through the input image analysis (S6). The peak luminance control unit 60 selects one of at least two peak luminance values or weighted average of at least two peak luminance levels using the weight values to determine the final peak luminance (S8). The peak luminance controller 60 adjusts the gamma high potential voltage (maximum gamma voltage) according to the final peak luminance and supplies the adjusted gamma high potential voltage MVDD to the gamma voltage generator 40 (S10). In other words, the peak luminance controller 60 selects the gamma high potential voltage corresponding to the final peak luminance, converts the selected gamma high potential voltage to an analog voltage, and supplies the analog voltage to the gamma voltage generator 40.

The gamma voltage generator 40 generates a gamma voltage set including a plurality of gamma voltages having different levels corresponding to the gradations and supplies them to the data driver 20. The gamma voltage generator 40 generates a gamma voltage set including a plurality of gamma voltages by dividing the gamma high potential voltage MVDD adjusted according to the final peak luminance through the resistance string from the peak luminance controller 60, do.

To this end, the gamma voltage generator 40 includes a resistor string (not shown) connected in series between the input of the gamma high potential power source (MVDD) adjusted by the peak brightness controller 60 and the ground. The gamma voltage generator 40 generates a gamma voltage set that is independent for each of R, G, and B using a resistor string divided into R, G, and B, or generates a common gamma voltage set using a common RGB resistor string It is also said.

The gamma voltage generator 40 adjusts the gamma high potential power source MVDD in accordance with the final peak brightness so as to adjust the gamma voltage V DDD with other gamma voltages depending on the gamma high potential power source MVDD. do. The gamma voltages adjusted by the gamma voltage generator 40 are supplied to the data signals of the respective pixels of the display panel 50 through the data driver 20 to control the respective pixel currents, 50 to reduce power consumption.

The data driver 20 converts the digital data from the timing controller 10 into an analog data signal in response to a data control signal from the timing controller 10 and supplies it to a plurality of data lines of the display panel 50. At this time, the data driver 20 subdivides the gamma voltage set from the gamma voltage generator 40 into gradation voltages corresponding to the gradation values of the data, and then uses the subdivided gradation voltages to convert the digital data into analog data signals .

The gate driver 30 sequentially drives a plurality of gate lines of the display panel 50 in response to a gate control signal from the timing controller 10. [ The gate driver 30 supplies a gate-on voltage to the respective gate lines in response to the gate control signal, and supplies a gate-off voltage in the remaining periods.

The display panel 50 includes a pixel matrix in which a plurality of red (R), green (G), and blue (B) subpixels connected to a data line, a gate line, a high potential power supply line, Respectively. Each sub-pixel has an OLED element and a pixel circuit for driving the OLED element. The pixel circuit includes at least a switching transistor and a driving transistor and a storage capacitor. The switching transistor charges the storage capacitor with a voltage corresponding to the data signal from the data line in response to the scan pulse from the gate line. The driving transistor controls the current supplied to the OLED element according to the voltage charged in the storage capacitor, Adjust the amount of light emitted by the device. The amount of light emission of the OLED element is proportional to the current supplied from the driving transistor.

As described above, the method and apparatus for controlling the peak luminance of the OLED display according to the embodiment of the present invention uses at least one of edge information and histogram distribution information showing image complexity in consideration of the luminance perception characteristics of the viewer as well as the APL, The power consumption can be maximized and the image quality can be improved.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of illustration, Can be carried out within a range. Accordingly, such modifications are deemed to be within the scope of the present invention, and the scope of the present invention should be determined by the following claims.

10: timing controller 20: data driver
30: gate driver 40: gamma voltage generator
50: display panel 60, 100, 200: peak brightness control section
110: APL detection unit 112, 122: Peak brightness setting unit
114: MUX 116: luminance-voltage conversion unit
118: DAC 124: weighted average operation unit
130: Edge gain generation unit 132: Edge extraction unit
134: Edge counter 136: Edge gain calculator
140: histogram gain generation unit 142: histogram generation unit
144: histogram distribution calculation unit 146: histogram gain calculation unit
150: operation unit 160: weight generation unit

Claims (11)

A first step of detecting an average picture level (APL) from an input picture;
A second step of setting at least two different peak luminances depending on the APL;
A third step of extracting at least one image characteristic information from edge information and histogram distribution information from the input image and generating a weight indicating a complexity of the image using the extracted image characteristic information;
And a fourth step of weighting averaging the at least two peak luminances by selecting one of the at least two peak luminances by using the weight or outputting a final peak luminance by using the weight. A method of controlling the peak luminance of a light emitting diode (OLED) display device. The method according to claim 1,
The second step
Wherein the at least two peak brightnesses corresponding to the APL are selected by using at least two lookup tables in which peak luminance for all the APLs are set different from each other in correspondence with at least two different peak luminance curves. A method of controlling peak brightness of a display device. The method according to claim 1,
In the third step,
Detecting and counting an edge from the input image to extract the edge information, and generating an edge gain using the edge information;
Generating and analyzing a histogram for each gradation from the input image, extracting the histogram distribution information indicating a distribution size of the histogram, and generating a histogram gain using the histogram distribution information;
And outputting the weighted gain by multiplying the edge gain and the histogram gain, or outputting one of the edge gain and the histogram gain as the weight value. The method according to claim 1,
The fourth step
Wherein the weighted average of the at least two peak luminances is calculated by using the following equation (1): " (1) "
&Quot; (1) "
Pout = w x P1 + (1-w) x P2
Here, P1 and P2 are the peak luminance, w is the weight, and Pout is the final peak luminance. The method according to claim 1,
Wherein the peak value is increased as the complexity of the image represented by at least one of the edge information and the histogram distribution information is higher and the final peak luminance is decreased as the weight value is increased. An APL detecting unit for detecting an APL from an input image;
A peak brightness setting unit for setting at least two different peak brightnesses according to the APL;
A weight generation unit for extracting at least one image characteristic information from edge information and histogram distribution information from the input image and generating a weight indicating a complexity of the image using the extracted image characteristic information;
And a peak luminance adjustment unit for selecting one of the at least two peak luminance using the weight or weight-averaging the at least two peak luminance using the weight and outputting a final peak luminance. A peak luminance control device of a display device. The method of claim 6,
The peak brightness setting unit
The at least two peak brightnesses corresponding to the APL supplied from the APL detecting unit are respectively selected using at least two lookup tables set to have different peak luminances for all APLs corresponding to at least two different peak brightness curves And the peak brightness of the OLED display device. The method of claim 6,
The weight generation unit
An edge gain generator for detecting and counting edges from the input image to extract the edge information and generating an edge gain using the edge information;
A histogram gain generation unit for generating and analyzing a histogram for each gradation from the input image, extracting the histogram distribution information indicating a distribution size of the histogram, and generating a histogram gain using the histogram distribution information;
And an arithmetic unit for multiplying the edge gain and the histogram gain and outputting the result as the weight value, or outputting one of the edge gain and the histogram gain as the weight value. The method of claim 6,
Wherein the peak brightness adjusting unit is a multiplexer for selecting any one of the at least two peak brightnesses according to the weight and outputting the selected one at the final peak brightness. The method of claim 6,
Wherein the peak luminance adjustment unit is a weighted average calculation unit that weight-averages the at least two peak luminance values using the weight values as in Equation (1) below and outputs the result as the final peak luminance value. .
&Quot; (1) "
Pout = w x P1 + (1-w) x P2
Here, P1 and P2 are the peak luminance, w is the weight, and Pout is the final peak luminance. The method of claim 6,
Wherein the peak value increases as the complexity of the image represented by at least one of the edge information and the histogram distribution information increases, and the final peak luminance decreases as the weight value increases.

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