KR102253677B1 - Display Device and Driving Method thereof - Google Patents

Abstract

The present invention relates to a display device including a display panel, a driving unit, and a control unit. The display panel displays an image. The driver drives the display panel. The control unit varies the driving frequency of the driving unit in response to the change in luminance of the display panel.

Description

Display device and driving method thereof TECHNICAL FIELD

The present invention relates to a display device and a driving method thereof.

As information technology develops, the market for display devices, which is a connection medium between users and information, is growing. Accordingly, a flat panel display (FPD) such as a liquid crystal display (LCD), an organic light emitting diode display (OLED), a plasma display panel (PDP), etc. ) Is on the rise. Among them, a liquid crystal display device capable of realizing high resolution and capable of miniaturization as well as enlargement is widely used.

Some of the above-described display devices, for example, a liquid crystal display device or an organic light emitting display device, include a display panel including a plurality of sub-pixels arranged in a matrix form and a driver driving the display panel. The driver includes a scan driver that supplies a scan signal (or a gate signal) to the display panel, and a data driver that supplies a data signal to the display panel.

In the above display device, when a scan signal and a data signal are supplied to subpixels arranged in a matrix form, the selected subpixel emits light, thereby displaying an image.

The display device is implemented in various products such as a television, a mobile device (eg, a smart phone), a wearable display device (eg, a smart watch), and a vehicle display device (eg, a navigation device). When the display device is implemented as a display device for user convenience (a mobile device, a wearable display device, a navigation device, etc.), it is necessary to lower power consumption so that it can be used for a long time.

The present invention for solving the problems of the above-described background technology is to reduce power consumption and display at the same time while varying the driving frequency and removing the flicker issue in consideration of the cognitive feature that the degree of flicker perception according to the change in luminance is changed. It is to improve the quality.

The present invention relates to a display device including a display panel, a driving unit, and a control unit as a means for solving the above problems. The display panel displays an image. The driver drives the display panel. The control unit varies the driving frequency of the driving unit in response to the change in luminance of the display panel.

The controller may increase the driving frequency when the luminance of the display panel increases, and may decrease the driving frequency when the luminance of the display panel decreases.

The control unit may vary the driving frequency step by step in response to the changing luminance section of the display panel.

The control unit varies the driving frequency step by step based on the flicker perception limit driving frequency prepared based on the changed luminance section of the display panel and the flicker perception characteristic data of a person, but the driving frequency may correspond to or be higher than the flicker perception limit driving frequency. have.

The difference between the driving frequency and the flicker perception limit driving frequency may be within 10 Hz.

Further comprising an illuminance sensing unit that detects external light and converts the detected light into an electric signal to generate an illuminance signal capable of determining illuminance, and a memory unit having a reference data value provided based on a person's luminance perception characteristic, The control unit may adjust the luminance of the display panel based on the reference data value and the illuminance signal, and may change the driving frequency corresponding to the variable luminance section.

In another aspect, the present invention relates to a method of driving a display device. A method of driving a display device includes driving a front panel; Determining whether luminance adjustment of the display panel occurs; And changing a driving frequency when the luminance of the display panel is adjusted.

In the step of varying the driving frequency, the driving frequency may be increased when the luminance of the display panel is increased, and the driving frequency may be decreased when the luminance of the display panel is decreased.

In the step of varying the driving frequency, the driving frequency may be changed step by step corresponding to the changed luminance section of the display panel.

The driving frequency is changed step by step based on the flicker perception limit driving frequency prepared based on the changed luminance section of the display panel and the flicker perception characteristic data of a person, but the driving frequency corresponds to or higher than the flicker perception limit driving frequency. I can.

The present invention has an effect of reducing power consumption by differentially applying a driving frequency according to the luminance of a display panel. In addition, in the present invention, since the driving frequency is varied in consideration of a cognitive feature in which the degree of flicker perception varies according to a change in luminance, there is an effect of improving display quality while removing a flicker issue. In addition, the present invention has an effect of reducing power consumption associated with a frame buffer and a related bus as well as a display panel by varying a driving frequency.

1 is a schematic block diagram of a display device.
FIG. 2 is a diagram illustrating an exemplary configuration of a sub-pixel shown in FIG. 1.
3 and 4 are diagrams for explaining an experimental example using a conventional display device.
5 and 6 are diagrams schematically illustrating a display device according to an exemplary embodiment of the present invention.
7 is a flowchart illustrating a method of driving a display device according to an exemplary embodiment of the present invention.
8 is a flowchart illustrating a method of setting a driving frequency for each luminance of FIG. 7.
9 is a graph showing the relationship between the flicker perception-limit driving frequency according to the luminance.
10 is a simulation result graph showing power consumption of the display panel according to the driving frequency of FIG. 9.
11 is an exemplary view of variable driving frequency when the illuminance detection unit is not used.
12 is an exemplary view of variable driving frequency when using an illuminance sensor.

Hereinafter, specific details for carrying out the present invention will be described with reference to the accompanying drawings.

1 is a schematic block diagram of a display device, and FIG. 2 is an exemplary configuration diagram of a sub-pixel shown in FIG. 1.

As shown in FIG. 1, the display device includes an image controller 180, a display panel 100, a timing controller 110, a data driver 120, a scan driver 130 and 140, a memory 160, and an illuminance. A sensing unit 170 is included.

The display panel 100 includes subpixels divided and connected to the data lines DL and the scan lines GL intersecting each other. The display panel 100 includes a display area 100A in which sub-pixels are formed and a non-display area 100B in which various signal lines or pads are formed outside the display area 100A. The display panel 100 may be implemented as a liquid crystal display panel, an organic light emitting display panel, an electrophoretic display panel, or the like. The display panel 100 is driven by the data driver 120 and the scan drivers 130 and 140.

As shown in FIG. 2, one sub-pixel SP is supplied in response to a scan signal supplied through a switching transistor SW and a switching transistor SW connected to the scan line GL1 and the data line DL1. A pixel circuit PC that operates in response to the data signal DATA is included. The sub-pixel SP is implemented as a liquid crystal display panel including a liquid crystal device or an organic light emitting display panel including an organic light emitting device, depending on the configuration of the pixel circuit PC.

When the display panel 100 is composed of a liquid crystal display panel, it is a TN (Twisted Nematic) mode, VA (Vertical Alignment) mode, IPS (In Plane Switching) mode, FFS (Fringe Field Switching) mode, or ECB (Electrically Controlled Birefringence) mode. It is implemented in mode. When the display panel 100 is composed of an organic light emitting display panel, it is implemented in a top-emission method, a bottom-emission method, or a dual-emission method.

The image controller 180 processes the data signal and outputs it together with a vertical synchronization signal, a horizontal synchronization signal, a data enable signal, and a clock signal. The image controller 180 supplies a vertical synchronization signal, a horizontal synchronization signal, a data enable signal, a clock signal, and a data signal to the timing controller 110. The image controller 180 is formed in the form of an integrated circuit (IC) on a system circuit board (such as a printed circuit board).

The timing controller 110 receives timing signals such as a vertical synchronization signal, a horizontal synchronization signal, a data enable signal, and a clock signal from the image controller 180 through an LVDS or TMDS interface receiving circuit connected to the system circuit board. The timing control unit 110 generates timing control signals for controlling the operation timing of the data driving unit 120 and the scan driving units 130 and 140 based on the input timing signal. The timing controller 110 is formed in the form of an IC on the control circuit board.

The data driver 120 includes a plurality of source drive ICs. The source drive ICs receive a data signal DATA and a source timing control signal DDC from the timing controller 110. The source drive ICs convert the data signal DATA from a digital signal to an analog signal in response to the source timing control signal DDC, and supply it through the data lines DL of the display panel 100. The source drive ICs are connected to the data lines DL of the display panel 100 by a chip on glass (COG) process or a tape automated bonding (TAB) process. The data driver 120 is formed in the form of an IC on a display panel or a source circuit board.

The scan driving units 130 and 140 are formed to include a level shifter unit 130 formed in an IC form or an IC form and a shift register unit 140 formed in a gate in panel (GIP) method.

The level shifter unit 130 is formed on a scan circuit board connected to the display panel 100. The level shifter 130 generates power along with the gate clock signal based on the on and off clock signals supplied from the timing control unit 110, and shifts the generated gate clock signal and the power level, and then shifts the register unit. Supply to (140). The level shifter 130 may be included in a power supply that generates and outputs power.

The shift register unit 140 is formed in the form of a thin film transistor in the non-display area 100B of the display panel 100. The shift register unit 140 includes stages for shifting and outputting a scan signal in response to a gate clock signal and power supplied from the level shifter 130. Stages included in the shift register unit 140 sequentially output scan signals through output terminals.

As described above, the level shifter unit 130 and the shift register unit 140 are separated from each other, and the built-in scan driver is implemented with the shift register unit 140 as an oxide or amorphous silicon thin film transistor. Oxide thin film transistors have an advantage of being able to reduce the size of a circuit compared to amorphous silicon thin film transistors because they have excellent current transfer characteristics. Since the amorphous silicon thin film transistor can maintain a constant threshold voltage over time, the amorphous silicon thin film transistor has a good advantage of recovering the threshold voltage according to the stress bias compared to the oxide thin film transistor.

The memory unit 160 has a reference data value prepared based on a person's luminance perception characteristic. The memory unit 160 provides the reference data value BRC stored therein to the timing controller 110.

The illuminance detector 170 detects (or receives) ambient light and converts the detected light into an electric signal to generate an illuminance signal LIS capable of determining illuminance. The illuminance sensor 170 supplies an illuminance signal LIS to the timing controller 110. The illuminance detection unit 170 is a sensor unit capable of detecting external light such as an optical sensor, a camera, and an illuminance sensor (Cds) and converting it into an electric signal, and a sensor unit capable of converting an analog type electric signal into a digital type electric signal. It may be composed of a conversion unit or the like.

The display device described above is implemented as a variety of products such as a television, a mobile device (eg, a smart phone), a wearable display device (eg, a smart watch), and a vehicle display device (eg, a navigation device). When the display device is implemented as a display device for user convenience (a mobile device, a wearable display device, a navigation device, etc.), it is necessary to lower power consumption so that it can be used for a long time.

Hereinafter, a description of an exemplary embodiment of the present invention will be embodied as an example in which the display device is implemented as a smart phone.

3 and 4 are diagrams for explaining an experimental example using a conventional display device, and FIGS. 5 and 6 are diagrams for schematically illustrating a display device according to an exemplary embodiment of the present invention.

As shown in FIGS. 3 and 4, a conventional smart phone was driven under two environmental conditions. As a result of driving the luminance of the display panel under the environmental conditions of 100 cd/m2 as shown on the right side of FIG. 3 and 400 cd/m2 as shown on the left, the conventional smart phone is equal to 60 Hz even if the brightness of the display panel is changed. Was driven at a frequency of.

According to a person's flicker perception characteristic (perception ability criterion), it is reported that the ability to perceive flicker at low luminance such as 100 cd/m2 environmental conditions is insensitive. On the other hand, it is reported that the ability to perceive flicker at high luminance such as 400 cd/m2 environmental conditions is sensitive.

As such, conventional devices use the same high driving frequency (mostly 60 Hz) without reflecting the flicker perception characteristic of a person (regardless of changes in luminance) even though the threshold frequency at which a person perceives flicker decreases as the luminance increases. Accordingly, there was a problem that it was difficult to reduce the power consumption. In addition, in the conventional device, when the driving frequency is lowered to reduce power consumption, there is a problem in that display quality is deteriorated due to problems such as flickering.

As shown in FIGS. 5 and 6, the device according to the embodiment of the present invention implements a smart phone such that a driving frequency varies differently when the luminance is varied based on the flicker perception characteristic data of a person.

And in the embodiment of the present invention, as in the experimental example, the smartphone was driven under two environmental conditions. In the device according to the exemplary embodiment of the present invention, when the luminance of the display panel is changed, the driving frequency is also changed in response thereto. As a result, it was confirmed that the embodiment of the present invention reduces power consumption compared to the conventional technology.

Furthermore, the apparatus according to an embodiment of the present invention is implemented to consider the flicker perception characteristic of a person, but divide the luminance into sections and follow the driving frequency accordingly when the luminance of the display panel falls within a specific range.

Specifically, the device according to the embodiment of the present invention is based on the ISO 13406-2 Flicker energy equation expressed below. And, when E _pred <E _obs , it is determined that flicker is recognized.

로 표현된다.Previously described

It is expressed as

In the above equation, E _pred means a flicker reference value, a and b are constants according to the visual angle, f is the driving frequency of the display panel, and e is a natural constant.

According to the ISO 13406-2 flicker energy formula, a and b have values as shown in Table 1 below according to the angle change.

[Table 1]

로 표현된다.Previously described

It is expressed as

로 표현될 수 있다. FFT(Fast Fourier Transform)는 주파수를 시간으로 변경했을 때의 진폭값을 의미한다.In the above equation, E _obs means human cognitive characteristics, L means luminance, and A means the size of the human eye (corresponding to the amount of light entering the eye), and A = b ₀ L ^b1 , C ₀ = L (b ₀ = 12.45184, b ₁ = -0.16032) can be expressed, C ₀ means the luminance (amount of light) in the dark room, and AMP is the flicker that appears on the display panel. As to mean the ratio of,

It can be expressed as FFT (Fast Fourier Transform) refers to the amplitude value when the frequency is changed to time.

The apparatus according to the embodiment of the present invention is implemented to adjust the driving frequency according to the luminance section based on the above equation under the conditions shown in Table 2 below. However, Table 2 shows ISO 13406-2 Annex. This is the result derived by applying a mobile prototype according to B.

[Table 2]

As can be seen from Table 2 above, the driving frequency is varied based on the changeable luminance section of the display panel and the flicker perception limit driving frequency prepared based on the flicker perception characteristic data of a person.

The driving frequency may be set to correspond to the flicker perception limit driving frequency or may be set higher than this by 1Hz to 10Hz. For example, when the luminance section is 50 cd/m2, the flicker perception limit driving frequency is 32.4Hz. Therefore, when the luminance section is 50 cd/m2, the driving frequency may be changed to 32.4Hz corresponding to the flicker perception limit driving frequency.

However, depending on the person, the driving frequency at which the flicker perception limit is felt may be different. For this reason, the driving frequency may be set to have a driving frequency + a margin value (a difference value between the driving frequency and the flicker perception limit driving frequency) in order to further consider the difference in the flicker perception limit characteristic according to the person. That is, in Table 2, the reason why 35Hz is not 32.4Hz as the driving frequency is because a margin value of 2.6Hz is included.

As can be seen from the above description, the driving frequency may be varied to correspond to the flicker recognition limit driving frequency, but the higher the frequency is, the lower the possibility of detecting the flicker.

For this reason, the driving frequency may be set higher than the flicker perception limit driving frequency by 1 Hz to 10 Hz. In terms of power consumption reduction, it is better to lower the driving frequency, so about 1 Hz, which is close to the flicker perception limit driving frequency, can be set as a margin value.

On the contrary, in terms of flicker improvement, since it is good to increase the driving frequency, a margin value of 2 Hz or more, 5 Hz or more, or 8 Hz or more, which is higher than the flicker perception limit driving frequency, can be set.

In response to the luminance section, the lower the driving frequency up to the flicker perception limit driving frequency, the more power consumption can be reduced, but the higher the driving frequency than the flicker perception limit driving frequency, the better the flicker improvement effect. I can. Therefore, in order to consider both power consumption and flicker improvement characteristics, it will be effective to vary the driving frequency to 1 Hz or more but not to exceed 10 Hz.

According to the above equations and experiments, it was found that humans tend to be insensitive to flicker as the luminance increases. Accordingly, the present invention implements the apparatus as follows so that the driving frequency is changed according to the change in luminance based on the cognitive characteristics described above.

1, 5, and 6, in the apparatus according to the embodiment of the present invention, the driving frequency of the device according to the embodiment of the present invention is differently changed based on the flicker recognition characteristic data of a person by the timing control unit 110. In particular, the timing control unit 110 is implemented such that the driving frequency is varied in response to the flicker perception characteristic data of a person when the luminance is varied.

To this end, the timing control unit 110 receives the reference data value BRC provided so that the driving frequency is variable in response to the flicker recognition characteristic data of a person from the memory unit 160, and the illuminance signal ( LIS) is delivered. In addition, the timing controller 110 adjusts the brightness of the display panel 100 based on the reference data value BRC and the illuminance signal LIS, and controls the data driver 120 and the scan driver in response to a variable brightness section. 130, 140) to vary the driving frequency.

Hereinafter, a method of driving a display device according to an exemplary embodiment of the present invention will be described.

7 is a flowchart illustrating a method of driving a display device according to an exemplary embodiment of the present invention, FIG. 8 is a flowchart illustrating a method of setting a driving frequency for each luminance of FIG. 7, and FIG. 9 is a flicker recognition-limit driving frequency according to luminance. And FIG. 10 is a graph showing a simulation result showing power consumption of the display panel according to the driving frequency of FIG. 9.

As shown in FIG. 7, after the device is driven to display an image on the display panel, when luminance is adjusted by the user and the illuminance sensor (illumination sensor) (S110), the standard luminance calculation for each sample (S120) is performed. It goes on. The luminance adjustment occurs manually by the user or, if there is an illuminance sensor, automatically by the sensor.

The reason that the standard luminance for each sample is calculated is that there may be a difference in luminance that can be implemented for each display panel. In the standard luminance calculation step S120 for each sample, the luminance may be calculated through a percentage (%) of the maximum luminance.

For example, if the maximum luminance of the display panel corresponding to the first sample is "max 400 cd/㎡ = 100%", the standard luminance is calculated as 50% luminance, such as "50% luminance setting = 200 cd/㎡". do. However, this is only an example, and the standard luminance calculation step S120 for each sample may be omitted depending on the process yield.

As described above, it is determined whether or not luminance adjustment of the display panel occurs by a user and an illuminance sensor (illumination sensor), and if it is determined that the brightness has been adjusted, a driving frequency for each luminance is set (S130). The driving frequency setting operation S130 for each luminance may be implemented so that the driving frequency is set based on an equation that is determined each time as described with reference to FIG. 6.

In addition, the driving frequency setting step S130 for each luminance may be implemented so that the driving frequency is set based on a look-up table (hereinafter abbreviated as LUT) stored in the memory unit. When the luminance increases, the driving frequency increases, and when the luminance decreases, the driving frequency decreases.

As shown in FIG. 8, a luminance section is set (S131). In the luminance section setting step (S131), it is determined by how many cd/m2 intervals the luminance is to be set. After the luminance section setting (S131) is made, a flicker energy analysis (S132) according to the luminance change is performed.

Flicker energy analysis determines that flicker is recognized when _{E pred} <E _obs as described with reference to FIG. 6. After flicker energy analysis (S132) is performed, driving frequencies for each luminance are derived (S133). As can be seen from Table 2, the driving frequency for each luminance is applied as a driving frequency higher than the flicker recognition and limit driving frequency.

For example, when the luminance section is 50 to 100 cd/m2, the flicker allowable driving frequency range is 35 to 40 Hz, and the flicker recognition-limit driving frequency is 37.3 Hz. However, the driving frequency to be applied is selected to be 40 Hz, which is higher than the flicker perception-limit driving frequency.

The reason for setting the driving frequency to be applied at a frequency higher than the flicker recognition-limit driving frequency is to set a margin so that flicker does not occur due to sudden changes in luminance.

As shown in FIG. 7, after the driving frequency for each luminance is set, driving frequency conversion (S140) is performed. The driving frequency conversion may be performed by the timing controller. The timing controller may perform driving frequency conversion based on an internal reference clock or a variable-frequency signal.

The driving frequencies of the data driving unit and the scan driving unit are varied by frequency conversion of the timing control unit. Meanwhile, in the above description, it has been described as an example that the driving frequency is changed by the timing control unit, but the driving frequency may also be changed by the image control unit.

After the driving frequency conversion (S140), an output image is transmitted (S150). The image transmission after the driving frequency is converted is performed by the data driver and the scan driver.

9 and 10, in the embodiment of the present invention, a device is implemented based on a liquid crystal display panel, and the power consumption of the liquid crystal display panel is measured according to the driving frequency by dividing it into two samples. I did. The first sample represents the power consumption when displaying full white, and the second sample represents the power consumption when displaying 8 colors.

As described above, as a result of implementing the device to adjust the driving frequency according to the luminance section based on the flicker perception-limit driving frequency according to the luminance (formula described above), the device according to the embodiment of the present invention has a low power consumption. It was confirmed that the savings were made. In addition, although not shown in the graph, the device according to the exemplary embodiment of the present invention has been shown to reduce power consumption by about 20% in parts related to the display panel and the frame buffer, compared to the conventional device.

Meanwhile, the liquid crystal display panel is generally driven at a driving frequency of 60 Hz due to a flicker issue caused by inversion driving. Accordingly, a device capable of changing a driving frequency in response to a change in luminance while solving the flicker issue as in the present invention is more effective when applied to a liquid crystal display panel. In addition, as the luminance of the display panel increases, the JND (a degree of recognizing a difference) of the driving frequency for recognizing flicker decreases, and thus power consumption may be further lowered by lowering the driving frequency under various conditions.

Hereinafter, a description for aiding understanding of the present invention is added.

FIG. 11 is an exemplary diagram illustrating a variable driving frequency when the illuminance sensor is not used, and FIG. 12 is an exemplary diagram illustrating a variable driving frequency when an illuminance sensor is used.

In the apparatus according to the embodiment of the present invention, the illuminance detection unit 170 and the timing control unit are not interlocked (when the illuminance detection unit is not provided or not used) to adjust the driving frequency according to the luminance section (example of FIG. 11) or In conjunction with the sensing unit, the driving frequency may be adjusted according to the luminance section (example of FIG. 12).

delete

(Example 1)

The timing controller 110 illustrated in FIG. 1 is implemented to analyze a data signal corresponding to an image to be displayed on the display panel 100 and calculate a luminance that can be displayed by the display panel 100. The timing controller 110 is implemented to adjust the driving frequency according to the luminance section using the calculated luminance information.

When the display device is implemented as described above, in the device according to the embodiment of the present invention, the illumination sensor 170 and the timing control unit 110 are not interlocked (when the illumination sensor is not provided or is not used). Accordingly, the timing controller 110 adjusts the driving frequency according to the luminance section based on the analysis of the data signal.

For example, when a bright image (eg, luminance 250 ~ 300 cd/m2) is displayed on the display panel of the device 200 implemented as a smartphone as shown in FIG. 11, the timing controller 110 increases the driving frequency (eg, F = 50 Hz). In contrast, when a slightly darker image (eg, luminance 100 ~ 150 cd/m2) is displayed on the display panel of the device 200 implemented as a smartphone, the timing control unit 110 lowers the driving frequency (eg, F = 42 Hz). ).

As in the above example, when the illuminance detection unit 170 is not used, outdoor visibility may be slightly lowered, but there is an advantage of reducing power consumption when used indoors. This is because the sensing operation of the illuminance sensor included in the illuminance sensor 170 can be omitted.

(Example 2)

The timing control unit 110 shown in FIG. 1 uses the illuminance signal LIS transmitted from the illuminance detection unit 170 and the reference data value BRC transmitted from the memory unit 160 to determine the driving frequency according to the luminance section. It is implemented to adjust.

When the display device is implemented as described above, in the device according to an embodiment of the present invention, the illuminance detection unit 170 and the timing control unit 110 are interlocked. For this reason, the timing controller 110 adjusts the driving frequency according to the luminance section that is automatically changed by the change of external light.

For example, as shown in FIG. 12, when a bright image is displayed on the display panel of the device 200 implemented as a smart phone and goes out to an environment with high illumination (eg, daytime), the timing controller 110 increases the driving frequency. When the same image as in FIG. 11 is displayed on the display panel, the luminance of the display panel is increased compared to the previous one by the illuminance sensor (eg, luminance 250 ~ 300 cd/㎡ -> luminance 350 ~ 400 cd/㎡), and driving along with The frequency will also increase (eg F = 50 Hz -> F = 55 Hz).

On the contrary, when a rather dark image is displayed on the display panel of the device 200 implemented as a smartphone and goes out to an environment with low illumination (eg, at night), the timing controller 110 lowers the driving frequency. When the same image as in FIG. 11 is displayed on the display panel, the luminance of the display panel is lowered compared to the previous one by the illuminance sensor (eg, luminance 100 ~ 150 cd/m2 -> luminance 50 ~ 100 cd/m2 ), and driving along with The frequency is also lowered (eg F = 42 Hz -> F = 40 Hz).

When the illuminance detection unit 170 is used as in the above example, the advantage of reducing power consumption may be slightly lowered, but there is an advantage of improving outdoor visibility. This is because a driving frequency adaptive to a change in luminance can be generated by a sensing operation of an illuminance sensor included in the illuminance sensor 170.

As described above, according to the present invention, power consumption can be reduced by differentially applying a driving frequency according to the luminance of the display panel. Further, according to the present invention, since the driving frequency is varied in consideration of a cognitive characteristic in which the degree of flicker perception varies according to a change in luminance, there is an effect of improving display quality while removing a flicker issue. In addition, the present invention has an effect of reducing power consumption associated with a frame buffer and a related bus as well as a display panel by varying a driving frequency.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical configuration of the present invention described above is in other specific forms without changing the technical spirit or essential features of the present invention by those skilled in the art. It will be appreciated that it can be implemented. Therefore, the embodiments described above are illustrative in all respects and should be understood as non-limiting. In addition, the scope of the present invention is indicated by the claims to be described later rather than the detailed description. In addition, all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

180: image control unit 100: display panel
110: timing control unit 120: data driving unit
130, 140: scan driving unit 160: memory unit
170: illuminance detection unit

Claims (10)

Display panel;
An illuminance detector configured to generate an illuminance signal for determining illuminance by sensing external light and converting the detected light into an electric signal;
A memory unit having a reference data value prepared based on a person's luminance perception characteristic;
A driver driving the display panel; And
A control unit for varying a driving frequency of the driving unit in response to a change in luminance of the display panel,
The control unit adjusts the luminance of the display panel based on the reference data value and the illuminance signal and varies the driving frequency in response to a variable luminance section,
The driving frequency is varied step by step based on a flicker perception limit driving frequency prepared based on the changed luminance section of the display panel and the flicker perception characteristic data of a person,
The display device according to claim 1, wherein the driving frequency corresponds to or higher than the flicker perception limit driving frequency. The method of claim 1,
The control unit
When the luminance of the display panel increases, the driving frequency is increased and
When the luminance of the display panel decreases, the driving frequency is lowered. delete delete The method of claim 1,
The display device, characterized in that the difference between the driving frequency and the flicker perception limit driving frequency is within 10 Hz. delete Driving the display panel;
Determining whether luminance adjustment of the display panel occurs; And
When the luminance of the display panel is adjusted, changing a driving frequency,
The step of varying the driving frequency is
When the luminance of the display panel is adjusted based on an illuminance signal that detects external light and converts the detected light into an electrical signal to determine illuminance and a reference data value prepared based on the luminance perception characteristic of a person,
The driving frequency is varied in response to a variable luminance section, but the driving frequency is varied step by step based on a flicker recognition limit driving frequency prepared based on the changed luminance section of the display panel and the flicker recognition characteristic data of a person,
The driving method of a display device, wherein the driving frequency corresponds to or higher than the flicker perception limit driving frequency. The method of claim 7,
In the step of varying the driving frequency,
When the luminance of the display panel increases, the driving frequency is increased and
When the luminance of the display panel is lowered, the driving frequency is lowered. delete delete

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