KR102164552B1 - Display Device - Google Patents

Abstract

The display device includes: a display unit that displays an image; A memory for storing a plurality of preset luminance regions; And a luminance control unit determining a luminance region including a maximum luminance to be displayed from the display unit from the luminance regions. The luminance control unit selects at least one driving of converting image data or adjusting a duty ratio of a light emission control signal based on at least a portion of the determined luminance region.

Description

Display Device

Embodiments of the present invention relate to an organic light emitting display device, and more particularly, to a dimming driving method of an organic light emitting display device capable of implementing a continuous dimming mode.

Organic Light Emitting Display Device is a kind of flat panel display device using organic compounds as a light emitting material. It has excellent luminance and color purity, as well as being thin, light, and capable of driving with low power. It is expected to be usefully used in various display devices.

However, the conventional organic light emitting display device has a disadvantage in that it is difficult to implement a dimming mode that adjusts the brightness (brightness) of a displayed image.

In the conventional case, a certain number of dimming steps (luminance levels) are set in advance to implement the dimming mode of the organic light emitting display device, and the gamma implementation for the step-by-step dimming steps is a method of applying a fixed gamma table collectively. A method of applying a gamma table at a maximum brightness level to each dimming step including a low brightness level in the same manner has been proposed.

However, in this case, there is a disadvantage in that the luminance and color of the image displayed for each dimming step may be non-uniform, and the luminance cannot be adjusted except for several preset dimming steps.

According to an exemplary embodiment of the present invention, in implementing a dimming mode of an organic light emitting display device, the dimming mode is divided into a plurality of luminance regions according to the intensity of luminance, and each luminance region corresponds to the dimming mode corresponding to each luminance region. An object of the present invention is to provide a dimming driving method of an organic light emitting display device capable of naturally implementing a continuous dimming mode by applying a different dimming driving method.

A display device according to an embodiment of the present invention includes: a display unit that displays an image; A memory for storing a plurality of preset luminance regions; And a luminance control unit for determining a luminance region including a maximum luminance to be displayed from the display unit from the luminance regions, wherein the luminance control unit converts image data or converts the light emission control signal based on at least a portion of the determined luminance region. At least one driving may be selected from among adjusting the duty ratio.

According to an embodiment, the luminance regions include first to fourth luminance regions, the first luminance region is an ultra-high luminance region, and the luminance of the highest gray scale corresponds to 300 nit to 250 nit, and the second luminance The region is a high luminance region, and the luminance of the highest gradation corresponds to 250 nit to 170 nit, the third luminance region is a medium luminance region, and the luminance of the highest gradation corresponds to 170 nit to 70 nit, and the fourth luminance region Is a low luminance region, and may be a region in which the highest grayscale luminance corresponds to 70 to 20 nit.

According to an embodiment, when the determined luminance region corresponds to the first luminance region, the luminance controller may select a dimming driving method for converting the image data.

According to an embodiment, in the dimming driving method through image data conversion, grayscales for each luminance at a maximum grayscale of 300nit are set as reference grayscales for each luminance, and grayscales indicated by image data in the determined luminance area are The image data may be converted according to the reference gray level by selecting a reference gray level corresponding to the luminance.

According to an embodiment, when the determined luminance region corresponds to the second luminance region, 250 nit, which is the highest gradation luminance, is set as a reference luminance, and gamma is fixed based on this, and the duty ratio of the emission control signal is adjusted. Dimming drive method can be selected.

According to an embodiment, when the determined luminance region corresponds to the second luminance region and the maximum grayscale luminance is 170 nits, the luminance controller may set the on duty ratio of the emission control signal to 60%.

According to an embodiment, when the determined luminance region corresponds to the third luminance region, the control unit fixes the on-duty ratio of the emission control signal to 60% and selects a dimming driving method for converting the image data. I can.

According to an embodiment, when the determined luminance region corresponds to the third luminance region and the highest grayscale luminance is 170 nits, the luminance controller may set the reference luminance to 250 nits.

According to an embodiment, when the determined luminance region corresponds to the third luminance region and the maximum grayscale luminance is 70 nits, the luminance controller may set the reference luminance to 110 nits.

According to an embodiment, when the determined luminance region corresponds to the fourth luminance region, the luminance controller sets 110 nits as a reference luminance, fixes a gamma based on this, and adjusts the duty ratio of the emission control signal. Dimming drive method can be selected.

According to an embodiment, when the determined luminance region corresponds to the fourth luminance region and the highest grayscale luminance is 70 nits, the luminance control unit may set the on duty ratio of the emission control signal to 60%.

According to an embodiment, when the determined luminance region corresponds to the fourth luminance region and the maximum grayscale luminance is 60 nits, the luminance controller may set the on duty ratio of the emission control signal to 50.5%.

According to an embodiment, when the determined luminance region corresponds to the fourth luminance region and the highest grayscale luminance is 50 nits, the luminance controller may set the on duty ratio of the emission control signal to 41.8%.

According to an embodiment, when the determined luminance region corresponds to the fourth luminance region and the luminance of the highest gray scale is 40 nits, the luminance controller may set the on duty ratio of the emission control signal to 33.2%.

According to an embodiment, when the determined luminance region corresponds to the fourth luminance region and the maximum grayscale luminance is 30 nits, the luminance controller may set the on duty ratio of the emission control signal to 24.5%.

According to an embodiment, when the determined luminance region corresponds to the fourth luminance region and the highest grayscale luminance is 20 nits, the luminance controller may set the on duty ratio of the emission control signal to 15.9%.

According to the exemplary embodiment of the present invention, in implementing the dimming mode of the organic light emitting display device, the luminance level corresponding to each dimming step is not divided into several fixed steps, and the dimming mode is set according to the intensity of the luminance. By dividing into a plurality of luminance regions, and applying a different dimming driving method for each luminance region corresponding to the dimming mode corresponding to each luminance region, there is an advantage in that it is possible to implement a continuous dimming mode naturally.

1 is a block diagram of an organic light emitting diode display according to an embodiment of the present invention.
2 is a diagram for explaining a dimming driving method through image data conversion.
3 is a view for explaining a dimming driving method by adjusting the duty ratio of the emission control signal.
4 is a circuit diagram illustrating a pixel illustrated in FIG. 1 by way of example.
5 is a driving waveform diagram of the pixel PX shown in FIG. 6A.
6 is a block diagram showing an embodiment of the brightness control unit of FIG. 1.
7 is a flowchart illustrating a dimming driving method of an organic light emitting display device according to an exemplary embodiment of the present invention.

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

1 is a schematic diagram of an organic light emitting display device according to an embodiment of the present invention.

Referring to FIG. 1, an organic light emitting display device 100 according to an exemplary embodiment of the present invention includes a pixel unit 110, a timing control unit 120, a scan driving unit 130, and a data driving unit 140. The timing control unit 120, the scan driver 130, and the data driver 140 may be formed on separate semiconductor chips, or may be integrated into one semiconductor chip. In addition, the scan driver 130 may be formed on the same substrate as the pixel portion 110.

The pixel unit 110 includes a plurality of pixels PX arranged in a matrix manner at an intersection of the scan lines SL1 to SLn arranged in rows and the data lines DL1 to DLm arranged in columns. The pixels PX receive a scan signal and a data signal from the scan lines SL1 to SLn and the data lines DL1 to DLn, respectively. In addition, a light emission control signal is supplied from the light emission control signal line ELm. The pixels PX display an image by emitting light corresponding to the scan signal, data signal, light emission control signal, and pixel power sources ELVDD and ELVSS. The emission time of the pixels PX may be adjusted in response to the emission control signal.

The scan driver 130 receives a scan control signal (SCS) and an emission duty control signal (EDCS) from the timing controller 120 to generate a scan signal and an emission control signal. At this time, the duty ratio of the emission control signal is adjusted in response to the emission duty control signal EDCS. The scan driver 130 may supply the generated scan signal and emission control signal to the pixels PX through the scan lines SL1 to SLn and the emission control signal lines EL1 to ELn. A data signal may be provided by sequentially selecting pixels PX for each row according to the scan signal. In addition, the emission time of the pixels PX may be adjusted according to the emission control signal. In the present embodiment, it is illustrated that the scan signal and the light emission control signal are generated by the same scan driver 130, but are not limited thereto. The display device 100 may further include an emission control driver, and a light emission control signal may be generated by the emission control driver.

The data driver 140 receives a data control signal (DCS) and image data (RGB') from the timing controller 120, and in response to the data control signal (DCS), the image data (RGB') is The corresponding data signal is supplied to the pixels PX through the data lines DL1 to DLm. The data driver 140 converts the received image data RGB' into a voltage or current data signal.

The timing controller 120 generates signals (SCS, EDCS, DCS) for controlling the scan driver 120 and the data driver 130 based on an image signal (RGB) and a control signal (CS) transmitted from the outside. Thus, it is provided to the scan driver 130 and the data driver 140. The control signal CS may be, for example, timing signals such as a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a clock signal CLK, and a data enable signal DE, or a signal for setting a dimming mode. In addition, the timing controller 120 converts an image signal RGB received from the outside and provides the converted image signal to the data driver 130. The timing controller 120 may include a graphic RAM (GRAM, not shown), and may temporarily store an image signal RGB of one frame received from the outside in the graphic RAM.

Meanwhile, the timing controller 120 may include a brightness controller 10. The luminance control unit 10 may adjust the light emission luminance of the pixel unit 110 by converting the image data RGB or adjusting a duty ratio of the emission control signal according to a preset dimming mode.

Hereinafter, a method of adjusting the luminance through image data conversion to correspond to the dimming mode set with reference to FIGS. 2 and 3 (Fig. 2) and a method of controlling the luminance by controlling the duty ratio of the emission control signal (Fig. 3). It will be described in detail.

2 is a diagram illustrating a dimming driving method through image data conversion.

This is a method of adjusting the luminance through image data conversion so as to correspond to the set dimming mode.The gradations for each luminance at a predetermined luminance level, such as the highest luminance level, are set as the reference gradation for each luminance, and when the dimming mode is changed , In the changed dimming mode, a method of selecting a reference grayscale corresponding to the luminance of grayscales represented by the image data and converting the image data according to the reference grayscale.

2 shows a case where the luminance of the highest gradation (255 gradation) is changed to a dimming mode (hereinafter referred to as 100 nit mode) in which the luminance of the highest gradation is 100 nit based on the highest luminance level of 300 nit (hereinafter referred to as 300 nit mode). Adjusting the luminance will be described as an example.

That is, grayscales for each luminance in the 300nit mode are set as the reference grayscale. When the image data represents 255 grayscales in the 100nit mode, the grayscale luminance at 255 grayscales should be 100nit. The standard grayscale corresponding to 100nit luminance is 155 grayscale. Accordingly, image data representing 255 grayscales is converted into image data representing 155 grayscales. For example, when the image data is an 8-bit digital signal, the signal '11111111' representing 255 gray levels is converted into '10011011' representing 155 gray levels. As another example, when the image data represents 100 grayscales in the 100nit mode, the grayscale luminance at 100 grayscales should be 15nit. Since the reference grayscale corresponding to 15nit is 66 grayscales, image data representing 100 grayscales is converted into image data representing 66 grayscales.

Through this, it is possible to change to a predetermined dimming mode (100 nit mode) by converting only image data without changing a setting (eg, voltage for each gradation) of the display device 100 set to the 300 nit mode, which is the maximum luminance level.

3 is a diagram for describing a dimming driving method by adjusting a duty ratio of a light emission control signal.

This is a method of adjusting the luminance by controlling the duty ratio of the emission control signal to correspond to the set dimming mode, and the ON period for one period (e.g., one frame) of the emission control signal that controls the emission and extinction of the pixel (PX). Alternatively, the luminance is changed by varying the off period. That is, by controlling the on duty ratio of the emission control signal to control the luminance, the on duty ratios of the emission control signal of 100%, 80%, 60%, 40%, 20%, and 5% are set. I can. However, this is an example, and various duty ratios can be set according to the user.

Referring to FIG. 3, the on period T2 of the emission control signal EM2 in the 100 nit mode is smaller than the on period T4 of the emission control signal EM1 in the 300 nit mode. Conversely, the off period T3 of the emission control signal EM2 is longer than the off period T1 in the 300 nit mode. When the pixels emit light during the on period of the emission control signal and the pixels are quenched during the off period, as the on period of the emission control signal decreases or the off period of the emission control signal increases, the luminance may decrease. In this case, the on-duty ratio of the emission control signals EM1 and EM2 for each luminance mode may be set in consideration of unique characteristics of the pixel unit 110.

Referring back to FIG. 1, the luminance control unit 10 according to an embodiment of the present invention may apply the above-described image data conversion method or the emission control signal duty ratio adjustment method, or a combination thereof to change to a predetermined dimming mode.

According to an exemplary embodiment of the present invention, in implementing a dimming mode of an organic light emitting display device, the dimming mode is divided into a plurality of luminance regions according to the intensity of luminance, and each luminance region corresponds to the dimming mode corresponding to each luminance region. It is characterized by applying a different dimming driving method, and through this, it is possible to realize a continuous dimming mode naturally.

More specifically, in the case of setting the dimming mode in which the luminance of the highest gradation (255 gradation) corresponds to 300 nit to 250 nit (hereinafter referred to as 300 nit to 250 nit mode), for example, the image data described above with reference to FIG. Dimming driving method through conversion is applied.

In addition, in the case of setting the dimming mode corresponding to the high luminance region, e.g., 250 nit to 170 nit mode, the luminance of the highest gradation, that is, the reference luminance, is set to 250 nit, and the gamma is fixed based on this, and the emission control signal as shown in FIG. The luminance is controlled by controlling the on duty ratio of. In this case, in the 170 nit mode, the on duty ratio of the emission control signal may be set to 60%.

That is, the dimming modes corresponding to the high luminance region are set to have the same reference luminance, and the on-duty ratio of the emission control signal is reduced to reduce the luminance. In this case, the image data is converted by setting the dimming mode to a reference luminance of 250 nits, but the on-duty ratio of the emission control signal is reduced, so that the luminance of the image displayed on the pixel unit 110 may be reduced according to the dimming mode.

In addition, in the case of setting the dimming mode corresponding to the medium luminance region, for example, 170nit to 70nit mode, the on-duty ratio of the emission control signal is fixed to 60%, and the dimming driving method through image data conversion described in FIG. 2 is applied. do.

However, in this case, since the on duty ratio of the light emission control signal is 60%, the luminance is lower than when the on duty ratio is 100%. Accordingly, in the 170 nit mode, when applying the dimming driving method shown in FIG. 2, the highest gradation luminance, that is, the reference luminance is set to 250 nit instead of 170 nit, and the 70 nit mode sets the reference luminance to 110 nit instead of 70 nit.

For example, in the 170 nit mode, by setting the reference luminance to 250 nit and the on duty ratio of the emission control signal to 60%, the luminance of an image displayed on the pixel unit 110 may be 170 nit.

In addition, in the case of setting the dimming mode corresponding to the low luminance region, for example, the 70 nit to 20 nit mode, the highest gradation luminance, that is, the reference luminance, is set to 110 nit, and gamma is fixed based on this, and emission control as in FIG. A method of controlling the luminance by controlling the on duty ratio of the signal is applied. In this case, in the case of the 70 nit mode, the on duty ratio of the light emission control signal is set to 60%, in the 60 nit mode, the on duty ratio is 50.5%, in the 50 nit mode, the on duty ratio is 41.8%, and in the 40 nit mode, the on duty ratio is set to 60%. The duty ratio may be set to 33.2%, the on duty ratio may be set to 24.5% in the 30nit mode, and the on duty ratio may be set to 15.9% in the 20nit mode.

That is, the luminance control unit 10 is a dimming mode (300 nit to 250 nit mode, 250 nit to 170 nit mode, 170 nit mode) for each of a plurality of luminance regions (super high luminance region, high luminance region, medium luminance region, low luminance region) corresponding to the intensity of luminance. ~ 70nit mode and 70nit ~ 20nit mode) are classified, and the optimized dimming driving method is applied to the dimming mode corresponding to each luminance region.

FIG. 4 is a circuit diagram illustrating the pixel illustrated in FIG. 1 by way of example, and FIG. 5 is a driving waveform diagram of the pixel PX illustrated in FIG. 6A.

Referring to FIGS. 4 and 5, the pixel PX includes a pixel circuit 1 including transistors T1 to T6 and a capacitor Cst and a light emitting device OLED.

The transistors T1 to T6 may be thin film transistors (TFTs), and the transistors T1 to T6 are P-type transistors. Also, driving may be performed by inverting the driving waveform of FIG. 5. In addition, in the present embodiment, the pixel circuit 1 is illustrated as including six transistors T1 to T6 and one capacitor Cst, but the present invention is not limited thereto. The number of transistors and capacitors constituting the pixel circuit 1 may vary.

The light-emitting element OLED receives a driving voltage through the pixel circuit 1 and emits light by itself. For example, the light emitting device OLED may be an organic light emitting diode (OLED).

During the initialization period, the previous scan signal Sn-1 of a low level is supplied through the previous scan line SLn-1. The initialization transistor T4 is turned on in response to the low-level previous scan signal Sn-1, and the initialization voltage Vint is applied to the gate electrode of the driving transistor T1 through the initialization transistor T4. It is connected, and the driving transistor T1 is initialized by the initialization voltage Vint.

Thereafter, during the data programming period, the low-level scan signal Sn is supplied through the scan line SLn. Then, the switching transistor T2 and the compensation transistor T3 are turned on in response to the low-level scan signal Sn.

At this time, the driving transistor T1 is diode-connected by the turned-on compensation transistor T3 and is biased in the forward direction.

Then, the compensation voltage (Dm+Vth, Vth is a value of (-)) reduced by the threshold voltage (Vth) of the driving transistor T1 from the data signal Dm supplied from the data line DLm is the driving transistor. It is applied to the gate electrode of (T1).

A driving voltage ELVDD and a compensation voltage Dm+Vth are applied to both ends of the capacitor Cst, and a charge corresponding to the voltage difference between both ends is stored in the capacitor Cst. Thereafter, during the light emission period Ton, the light emission signal EMn supplied from the light emission signal line ELn is changed from the high level to the low level. Then, the operation control transistor T5 and the light emission control transistor T6 are turned on by the low-level light emission signal EMn during the light emission period Ton.

Then, a driving current Id according to a voltage difference between the voltage of the gate electrode of the driving transistor T1 and the driving voltage ELVDD is generated, and the driving current Id is transmitted through the light emission control transistor T6. OLED).

During the light emission period, the gate-source voltage Vgs of the driving transistor T1 is maintained at {(Dm+Vth)-ELVDD} by the storage capacitor Cst, and according to the current-voltage relationship of the driving transistor T1, The driving current Id is proportional to the square {(Dm-ELVDD) ² } of the gate-source voltage minus the threshold voltage. That is, the emission luminance of the organic light emitting diode OLED may be controlled according to the data signal Dm.

In addition, the light emission luminance may be controlled according to the duty ratio of the light emission period Ton of the organic light-emitting device OLED according to the emission control signal EMn or the duty ratio of the light emission period Toff. Even if the same data signal Dm is applied, the higher the duty ratio of the light emission period Ton for one period including the emission period Ton and the extinction period Toff, for example, the display period of one frame, the organic light-emitting device OLED ) Has high luminance. Conversely, as the duty ratio of the extinction period Toff to the display period of one frame increases, the emission luminance of the organic light-emitting device OLED decreases. Accordingly, the emission luminance of the organic light-emitting device OELD may be controlled according to the data signal Dm and the emission control signal EMn.

6 is a block diagram illustrating an embodiment of the brightness control unit of FIG. 1.

6, the luminance control unit 10 includes a dimming mode determination unit 15, a reference luminance selection unit 14, a duty ratio setting unit 11, a gamma setting unit 12, and a data conversion unit 13. Can include.

As described above, the luminance control unit 10 is a dimming mode (300 nit to 250 nit mode, 250 nit to 170 nit mode) for each of a plurality of luminance regions (ultra high luminance region, high luminance region, medium luminance region, low luminance region) corresponding to the intensity of luminance as described above. , 170nit ~ 70nit mode, 70nit ~ 20nit mode), and operate to apply the optimized dimming driving method to the dimming mode corresponding to each luminance region.

That is, the luminance control unit 10 determines which luminance region among the plurality of luminance regions is the selected dimming mode, and emits light in response to a dimming mode corresponding thereto based on a predetermined reference luminance for each luminance region. The converted image data RGB' may be provided to the data driver 140 by generating the duty control signal EDCS and/or converting the image data RGB.

The dimming mode determination unit 15 determines which of the plurality of luminance regions (ultra high luminance region, high luminance region, medium luminance region, and low luminance region) that the dimming mode selected by the user corresponds to each luminance intensity, The determination result is output as a dimming mode signal DMS.

The reference luminance selector 14 may select a reference luminance corresponding thereto in response to the dimming mode signal DMS. For example, the dimming mode (300nit ~ 250nit mode) corresponding to the ultra-high luminance area has a reference luminance of 300nit, and the dimming mode (250nit ~ 170nit mode) corresponding to the high luminance area has a reference luminance of 250nit, and corresponds to the low luminance area. In the dimming mode (70nit to 20nit mode), the reference luminance is 110nit.

However, in the case of the dimming mode (170nit ~ 70nit mode) corresponding to the medium luminance region, the reference luminance may be changed for each dimming mode. For example, the 170nit mode sets the reference luminance to 250nit, and the 70nit mode is the reference luminance. Is set to 110nit.

The duty ratio setting unit 11, the gamma setting unit 12, and the data conversion unit 13 may operate in response to the reference luminance RBR output from the reference luminance selection unit 14.

The duty ratio setting unit 11 may generate and output an emission duty control signal EDCS for adjusting a duty ratio of the emission control signal in response to the reference luminance RBR and the dimming mode signal DMS. The emission duty control signal EDCS may set the duty ratio of the extinction period or the emission period of the emission control signal to 10% to 90%.

However, in the case of the dimming mode (300nit to 250nit mode) corresponding to the ultra high luminance region, since the dimming driving method through image data conversion is applied, a separate emission duty control signal may not be output.

In addition, in the case of the dimming mode (170nit to 70nit mode) against the medium luminance region, an emission duty control signal may be output so that the on duty ratio of the emission control signal is fixed at 60%.

The gamma setting unit 12 sets a gamma value corresponding to the selected dimming mode, which includes a lookup table to which a gamma value according to the dimming mode is mapped, and may select a gamma by referring to the lookup table.

The data converter 13 may generate and output the converted image data RGB' obtained by converting the image data RGB according to the dimming mode. The data conversion unit 13 may include a reference grayscale lookup table LUT_RGY in which reference grayscales for each luminance are mapped based on a predetermined luminance and gamma. The predetermined luminance may be an initial luminance or a maximum luminance level set before the luminance change. For example, the predetermined luminance may be 300 nit and the gamma may be 2.2.

The gamma setting unit 12 may calculate a reference luminance and a luminance for each gradation according to a gamma, and select a reference gradation corresponding to the calculated luminance from the reference gradation lookup table LUT_RGY. After that, the image data RGB may be converted into image data RGB' representing the reference gray level.

7 is a flowchart illustrating a dimming driving method of an organic light emitting display device according to an exemplary embodiment of the present invention.

Referring to FIG. 7, it is determined which of the first internal fourth luminance regions (ultra-high luminance region, high luminance region, medium luminance region, and low luminance region) that the dimming mode selected by the user corresponds to the intensity of luminance. , The determination result is output as a dimming mode signal DMS. (ST1)

For example, the dimming mode corresponding to the ultra-high luminance region (first luminance region) is 300 nit to 250 nit mode, the dimming mode corresponding to the high luminance region (second luminance region) is 250 nit to 170 nit mode, and the medium luminance region (third luminance region) The dimming mode corresponding to the luminance region) is a 170nit to 70nit mode, and the dimming mode corresponding to the low luminance region (the fourth luminance region) is a 70nit to 20nit mode.

Accordingly, when the selected dimming mode is a dimming mode corresponding to an ultra-high luminance region, the dimming driving method through image data conversion described above with reference to FIG. 2 is applied. (ST2-1)

That is, the gradation for each luminance in the 300nit mode in which the highest gradation (255 gradation) is 300nit is set as a reference gradation for each luminance, and in the selected dimming mode, a reference gradation corresponding to the luminance of the gradations represented by image data is selected. And, the image data is converted according to the reference gray level.

In addition, when the selected dimming mode is a dimming mode corresponding to a high luminance region, the luminance of the highest gradation, that is, the reference luminance is set to 250 nits, and the gamma is fixed based on this, and the on duty ratio of the emission control signal ( On duty ratio) is controlled to adjust the luminance, that is, a dimming driving method is applied by adjusting the duty ratio of the emission control signal. (ST2-2)

In this case, in the 170 nit mode, the on duty ratio of the emission control signal may be set to 60%.

That is, the dimming modes corresponding to the high luminance region are set to have the same reference luminance, and the on-duty ratio of the emission control signal is reduced to reduce the luminance. In this case, the image data is converted by setting the dimming mode to a reference luminance of 250 nits, but the on-duty ratio of the emission control signal is reduced, so that the luminance of the image displayed on the pixel unit 110 may be reduced according to the dimming mode.

In addition, when the selected dimming mode is a dimming mode corresponding to the medium luminance region, the on duty ratio of the emission control signal is fixed at 60%, and the dimming driving method through image data conversion described in FIG. 2 is applied. (ST2-3)

However, in this case, since the on duty ratio of the light emission control signal is 60%, the luminance is lower than when the on duty ratio is 100%. Accordingly, in the 170 nit mode, when applying the dimming driving method shown in FIG. 2, the highest gradation luminance, that is, the reference luminance is set to 250 nit instead of 170 nit, and the 70 nit mode sets the reference luminance to 110 nit instead of 70 nit.

For example, in the 170 nit mode, by setting the reference luminance to 250 nit and the on duty ratio of the emission control signal to 60%, the luminance of an image displayed on the pixel unit 110 may be 170 nit.

In addition, when the selected dimming mode is the dimming mode corresponding to the low luminance region, the luminance of the highest grayscale, that is, the reference luminance, is set to 110 nits, and gamma is fixed based on this, and the duty ratio of the emission control signal is adjusted as shown in FIG. The dimming driving method is applied. (ST2-4)

In this case, in the case of the 70 nit mode, the on duty ratio of the light emission control signal is set to 60%, in the 60 nit mode, the on duty ratio is 50.5%, in the 50 nit mode, the on duty ratio is 41.8%, and in the 40 nit mode, the on duty ratio is set to 60%. The duty ratio may be set to 33.2%, the on duty ratio may be set to 24.5% in the 30nit mode, and the on duty ratio may be set to 15.9% in the 20nit mode.

Thereafter, the pixel unit is driven in response to the image data converted through one of steps ST2-1 to ST2-4 and a light emission control signal whose duty ratio is adjusted in response to the selected dimming mode. (ST3)

Those of ordinary skill in the art to which the present invention pertains will understand that the present invention can be implemented in a modified form without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments should be considered from an illustrative point of view rather than a limiting point of view. The scope of the present invention is shown in the claims rather than the above description, and the invention claimed by the claims and the inventions equivalent to the claimed invention should be construed as being included in the invention.

10: brightness control unit 11: duty ratio setting unit
12: Gamma setting unit 13: Data conversion unit
14: reference luminance selection unit 15: dimming mode determination unit

Claims (16)

A display unit that displays an image;
A memory for storing a plurality of preset luminance regions;
In response to the luminance of the selected dimming mode, comprising a luminance control unit for determining a luminance region including a maximum luminance to be displayed from the display unit from the luminance regions,
The luminance regions include a first luminance region and a second luminance region,
When the determined luminance region corresponds to the first luminance region, the luminance control unit fixes the on duty ratio of the emission control signal, converts image data according to the luminance of the selected dimming mode,
When the determined luminance region corresponds to the second luminance region, the luminance controller fixes a gamma based on the luminance of the selected dimming mode, and adjusts the duty ratio of the emission control signal according to the luminance of the selected dimming mode. Regulating display. The method of claim 1, wherein the luminance regions further include a third luminance region and a fourth luminance region,
The first luminance region is an ultra-high luminance region, and the luminance of the highest gray scale corresponds to 300 nit to 250 nit,
The second luminance region is a high luminance region, and the luminance of the highest gray scale corresponds to 250 nit to 170 nit,
The third luminance region is a medium luminance region, and a luminance of the highest gray scale corresponds to 170 nit to 70 nit,
The fourth luminance region is a low luminance region, and the luminance of the highest gray scale corresponds to 70 nit to 20 nit. The method of claim 2,
When the determined luminance region corresponds to the first luminance region, the luminance control unit sets gradations for each luminance at a maximum luminance of 300 nit as reference gradations for each luminance, and the emission control signal A display device comprising: fixing an on duty ratio to 100%, selecting a reference grayscale corresponding to the luminance of the selected dimming mode among the reference grayscales, and converting image data according to the reference grayscale. delete The method of claim 2,
When the determined luminance region corresponds to the second luminance region, 250 nit, which is the highest gradation luminance, is set as a reference luminance, and gamma is fixed based on this, and the duty ratio of the light emission control signal corresponds to the luminance of the dimming mode To adjust the display device. The method of claim 5,
When the determined luminance region corresponds to the second luminance region and the luminance of the highest gradation is 170 nits, the luminance control unit sets an on duty ratio of the emission control signal to 60%. The method of claim 2,
When the determined luminance region corresponds to the third luminance region, the control unit fixes the on duty ratio of the emission control signal to 60% and converts the image data based on the luminance in the dimming mode. . The method of claim 7,
When the determined luminance region corresponds to the third luminance region and the luminance of the highest gradation is 170 nits, the luminance control unit sets a reference luminance to 250 nits. The method of claim 7,
When the determined luminance region corresponds to the third luminance region and the highest gradation luminance is 70 nits, the brightness control unit sets a reference luminance to 110 nits. The method of claim 2,
When the determined luminance region corresponds to the fourth luminance region, the luminance control unit sets 110 nits as a reference luminance, fixes a gamma based on this, and adjusts a duty ratio of the emission control signal. The method of claim 10,
When the determined luminance region corresponds to the fourth luminance region and the luminance of the highest gray scale is 70 nits, the luminance control unit sets an on duty ratio of the light emission control signal to 60%. The method of claim 10,
When the determined luminance region corresponds to the fourth luminance region and the luminance of the highest gray scale is 60 nits, the luminance control unit sets an on duty ratio of the light emission control signal to 50.5%. The method of claim 10,
When the determined luminance region corresponds to the fourth luminance region and the luminance of the highest gradation is 50 nits, the luminance control unit sets an on duty ratio of the emission control signal to 41.8%. The method of claim 10,
When the determined luminance region corresponds to the fourth luminance region and the luminance of the highest gray scale is 40 nits, the luminance control unit sets an on duty ratio of the emission control signal to 33.2%. The method of claim 10,
When the determined luminance region corresponds to the fourth luminance region and the luminance of the highest gray scale is 30 nits, the luminance control unit sets the on duty ratio of the emission control signal to 24.5%. The method of claim 10,
When the determined luminance region corresponds to the fourth luminance region and the luminance of the highest gray scale is 20 nits, the luminance control unit sets the on duty ratio of the emission control signal to 15.9%.

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