KR102532108B1 - Display device and driving method thereof - Google Patents

Abstract

The present embodiments relate to a display device driven by the FSC driving method and a method of driving the display device, wherein the interval between emission sections of subframes included in the same image frame is shorter than the interval between emission sections included in other image frames. By setting it short, it is possible to prevent color break up that may occur when switching video frames when displaying images in the FSC driving method. In addition, a flicker caused by a luminance difference between white and other colors can be prevented by driving a light emitting unit emitting white color together with a driving section of a light emitting unit emitting light of another color.

Description

Display device and method of driving the display device {DISPLAY DEVICE AND DRIVING METHOD THEREOF}

The present embodiments relate to a display device and a method of driving the display device.

As the information society develops, demands for display devices for displaying images are increasing in various forms. Accordingly, various types of display devices such as a liquid crystal display device, a plasma display device, and an organic light emitting display device have recently been utilized.

Such a display device includes a display panel including a plurality of pixels defined in an area where a plurality of gate lines and a plurality of data lines are disposed and the gate lines and the data lines intersect. Then, an image is displayed by driving each pixel through the data line at the driving timing of each pixel by the gate line.

That is, an image to be displayed is displayed by controlling the gray level of each pixel through the data voltage supplied through the data line.

Since such a display device displays an image by controlling gray levels of a plurality of pixels disposed on a display panel, it is very important to improve luminance performance of each pixel.

As one of the driving methods for improving luminance performance according to such demand, there is a Field Sequential Color (FSC) driving method.

The FSC driving method configures one image frame with a plurality of subframes and sequentially displays different colors in each subframe so that the colors displayed in each subframe are combined to be recognized as one image.

However, this FSC driving method has a problem in that color break up occurs at the moment the video frame is switched, and a phenomenon that is recognized as flickering due to the difference in luminance of each color (flicker) occurs. this exists

An object of the present embodiments is to provide a display device with improved quality of an image displayed by the display device and a method for driving the display device.

An object of the present embodiments is to provide a display device that prevents color break up at the moment an image frame is switched in a display device driven by the FSC driving method and a method for driving the display device. .

An object of the present embodiments is to provide a display device and a driving method for preventing a phenomenon (flicker) in which an image is recognized as flickering in a display device driven by the FSC driving method.

In one aspect, the present embodiments provide a display device in which one image frame is composed of a plurality of subframes and driven to display an image, and a method for driving the display device.

A plurality of subframes included in such an image frame may have the same length and display different colors.

For example, when one image frame is composed of two subframes, the first light emitter emits light in the first subframe and the second emitter emits light in the second subframe to display an image.

The first light emitting unit and the second light emitting unit may be light sources that uniformly radiate light to all pixels disposed on the display panel.

In this case, the interval between emission sections of subframes included in the same image frame and adjacent to each other may be shorter than the interval between emission sections of subframes included in different image frames and adjacent to each other.

That is, the interval between emission sections of subframes in an image frame may be set shorter than the interval between emission sections of subframes of the next image frame, so that the intervals between emission sections may be set to be asymmetrical.

In addition, one of the first light emitting unit and the second light emitting unit may emit white light, and the white light emitting unit may emit light in both the light emitting section of the first subframe and the second subframe.

In another aspect, the present embodiments include the steps of driving the first light emitter in the light emission period of the first subframe of an image frame composed of a plurality of subframes of the same length, and the step of driving the first light emitter in the light emission period of the second subframe of the image frame. A step of driving a second light emitting unit that emits light in a different color from the first light emitting unit, and the interval between the light emitting period of the first subframe and the light emitting period of the second subframe is included in another image frame and adjacent to each other. A driving method of a display device shorter than the interval between emission sections is provided.

According to the present embodiments, in a display device driven by the FSC driving method, by setting the interval between the emission intervals between subframes and the emission intervals between image frames to be asymmetrical, a phenomenon in which color is broken during FSC driving (Color Break Up) It is possible to provide a display device and a driving method for preventing the

According to the present embodiments, a phenomenon (flicker) that is perceived as flickering due to a difference in luminance between subframes is prevented by allowing a light emitting unit that emits light in white color to emit light at the driving timing of a light emitting unit that emits light in a different color in the FSC driving method. It is possible to provide a display device and a driving method thereof.

1 is a diagram showing a schematic configuration of a display device according to the present embodiments.
2 and 3 are diagrams showing a first embodiment of driving timing of a display device driven by the FSC driving method according to the present embodiments.
4 and 5 are diagrams illustrating a second embodiment of driving timing of a display device driven by the FSC driving method according to the present embodiments.
6 is a diagram showing a third embodiment of driving timing of a display device driven by the FSC driving method according to the present embodiments.
7 is a flowchart illustrating a process of a method of driving a display device driven by the FSC driving method according to the present embodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention are described in detail below with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same numerals as much as possible even if they are displayed on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description may be omitted.

In addition, in describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish the component from other components, and the nature, sequence, order, or number of the corresponding component is not limited by the term. When an element is described as being “connected,” “coupled to,” or “connected” to another element, that element is or may be directly connected to that other element, but intervenes between each element. It will be understood that may be "interposed", or each component may be "connected", "coupled" or "connected" through other components.

1 is a diagram showing a schematic configuration of a display device 100 according to the present embodiments.

Referring to FIG. 1 , in the display device 100 according to the present embodiments, a plurality of gate lines GL and a plurality of data lines DL are disposed and the gate lines GL and the data lines DL cross each other. The display panel 110 including a plurality of pixels disposed in the area where a plurality of pixels are disposed, a gate driver 120 driving a plurality of gate lines GL, and a data driver supplying data voltages to a plurality of data lines DL. 130, and a controller 140 that controls driving of the gate driver 120 and the data driver 130.

The gate driver 120 sequentially drives the plurality of gate lines GL by sequentially supplying scan signals to the plurality of gate lines GL.

The data driver 130 drives the plurality of data lines DL by supplying data voltages to the plurality of data lines DL.

The controller 140 controls the gate driver 120 and the data driver 130 by supplying various control signals to the gate driver 120 and the data driver 130 .

The controller 140 starts scanning according to the timing implemented in each frame, converts input image data input from the outside to suit the data signal format used by the data driver 130, and outputs the converted image data. , data drive is controlled at an appropriate time according to the scan.

The gate driver 120 sequentially supplies a scan signal of an on voltage or an off voltage to the plurality of gate lines GL under the control of the controller 140 to operate the plurality of gate lines GL. run sequentially.

The gate driver 120 may be located on only one side of the display panel 110 or on both sides of the display panel 110 depending on the driving method.

In addition, the gate driver 120 may include one or more gate driver integrated circuits.

Each gate driver integrated circuit is connected to a bonding pad of the display panel 110 by a tape automated bonding (TAB) method or a chip on glass (COG) method, or by a GIP ( Gate In Panel) type and can be directly disposed on the display panel 110 .

In addition, it may be integrated and disposed on the display panel 110 or may be implemented in a chip on film (COF) method mounted on a film connected to the display panel 110 .

When a specific gate line GL is opened, the data driver 130 converts the image data received from the controller 140 into an analog data voltage and supplies it to the plurality of data lines DL, thereby reducing the number of data lines DL. drive

The data driver 130 may include at least one source driver integrated circuit to drive a plurality of data lines DL.

Each source driver integrated circuit is connected to a bonding pad of the display panel 110 by a tape automated bonding (TAB) method or a chip on glass (COG) method, or It may be directly disposed on 110 or may be integrated and disposed on display panel 110 .

In addition, each source driver integrated circuit may be implemented in a Chip On Film (COF) method. In this case, one end of each source driver integrated circuit is bonded to at least one source printed circuit board, and the other end is bonded to the display panel 110 .

The controller 140 generates various timing signals including a vertical sync signal (Vsync), a horizontal sync signal (Hsync), an input data enable (DE) signal, and a clock signal (CLK) together with the input image data. Receive from outside (e.g. host system).

The controller 140 converts the input video data input from the outside to suit the data signal format used by the data driver 130 and outputs the converted video data, as well as the gate driver 120 and the data driver 130. In order to control the gate driver ( 120) and the data driver 130.

For example, in order to control the gate driver 120, the controller 140 includes a gate start pulse (GSP), a gate shift clock (GSC), and a gate output enable signal (GOE: It outputs various gate control signals (GCS: Gate Control Signal) including Gate Output Enable).

Here, the gate start pulse GSP controls the operation start timing of one or more gate driver integrated circuits constituting the gate driver 120 . The gate shift clock (GSC) is a clock signal commonly input to one or more gate driver integrated circuits and controls the shift timing of the scan signal. The gate output enable signal GOE specifies timing information of one or more gate driver integrated circuits.

In addition, the controller 140, in order to control the data driver 130, a source start pulse (SSP: Source Start Pulse), a source sampling clock (SSC: Source Sampling Clock), a source output enable signal (SOE: Source Output It outputs various data control signals (DCS) including Enable) and the like.

Here, the source start pulse SSP controls data sampling start timing of one or more source driver integrated circuits constituting the data driver 130 . The source sampling clock (SSC) is a clock signal that controls sampling timing of data in each source driver integrated circuit. The source output enable signal SOE controls output timing of the data driver 130 .

The controller 140 is a source printed circuit board to which the source driver integrated circuit is bonded and a control printed circuit board connected through a connection medium such as a flexible flat cable (FFC) or a flexible printed circuit (FPC). (Control Printed Circuit Board).

On this control printed circuit board, a power controller (not shown) is further disposed to supply various voltages or currents to the display panel 110, gate driver 120, and data driver 130 or to control various voltages or currents to be supplied. It can be. Such a power controller is also referred to as a power management IC.

The plurality of pixels are disposed in an area where the gate line GL and the data line DL intersect, and supply the data voltage output from the data driver 130 when the scan signal is output by the gate driver 120. Receive and display the video.

A plurality of pixels may display an image in a combination of colors displayed in each subframe in an image frame composed of a plurality of subframes having the same length.

For example, one video frame is composed of three subframes, and red, blue, and green colors are displayed in each subframe. Three colors are sequentially displayed in different subframes, and the displayed colors are combined to be recognized as an image to be displayed.

This driving method is called a Field Sequential Color (FSC) driving method. In the FSC driving method, the length of each subframe is the same and the interval between emission sections in each subframe is constant.

That is, the interval between emission sections of sub-frames within one image frame and the interval between emission sections between image frames are the same.

Accordingly, at the moment when one image frame is switched to another image frame, a color break-up phenomenon in which the human eye perceives a color other than the desired color to be displayed may occur.

In the present embodiments, in the display device 100 driven by the FSC driving method, the above-described color break up phenomenon (Color Break Up) can be prevented, and furthermore, flicker caused by a difference in luminance between colors can be prevented. A possible FSC driving method and a display device 100 driven by the driving method are provided.

2 is a diagram showing a first embodiment of the driving timing of the display device 100 driven by the FSC driving method according to the present embodiments.

Referring to FIG. 2 , the display device 100 driven by the FSC driving method according to the present embodiments displays images through image frames such as a first image frame, a second image frame, and a third image frame.

Each image frame may be composed of a plurality of subframes having the same length, and FIG. 2 shows an example in which one image frame is composed of a first subframe and a second subframe.

The display device 100 sequentially displays different colors in a first subframe and a second subframe having the same length, and uses a combination of the color displayed in the first subframe and the color displayed in the second subframe. Indicates the image to be displayed.

The display device 100 drives the first light emitting unit in the light emitting period of the first subframe and drives the second light emitting unit in the light emitting period of the second subframe.

In this case, the interval S1 between the emission interval of the first subframe and the emission interval of the second subframe included in one image frame is set to be asymmetrical with the interval S2 between the emission interval of the other image frame.

For example, the interval S1 between the emission period of the first subframe and the emission period of the second subframe in the first image frame is the emission period of the second subframe of the first image frame and the emission period of the second subframe of the first image frame. It may be set shorter than S2, which is an interval between emission sections of subframes.

That is, the interval S1 between emission sections of adjacent subframes within one image frame is set shorter, and the interval between emission sections of adjacent subframes included in another image frame is set longer than S1.

The difference between the interval S1 and the interval S2 may be set to an optimal value according to the quality of the image displayed in the FSC driving method.

In addition, when one image frame is composed of three or more subframes, the interval between emission sections of each subframe is set constant.

Therefore, by setting the length of the subframe and the interval between the emission sections within the subframe to be the same within the same image frame, an image with improved luminance can be displayed with a combination of different colors sequentially displayed in each subframe. do.

At the same time, by setting the interval S2 between the emission intervals of different image frames longer than the interval S1 between the emission intervals of the subframes in the same image frame, the color break phenomenon that may occur in the displayed image at the moment the image frame is switched (Color Break) Up) can be prevented.

That is, by asymmetrically setting the interval between the emission sections of the subframes included in the video frame, color break up, which is a problem of the FSC driving method, occurs while maintaining the luminance increasing effect, which is an advantage of the FSC driving method. Do not do this.

3 shows a case where the FSC driving method according to the first embodiment is applied to a liquid crystal display.

Referring to FIG. 3 , a case in which only a red color filter and a green color filter are disposed in each pixel disposed on the display panel 110 and no blue color filter is disposed is illustrated as an example.

Since the blue color filter is removed, images are displayed using blue and white LEDs as LED light sources.

In addition, FSC driving may be performed using LEDs that emit light in each color without arranging all color filters, and the present embodiments include all combinations in which color filters are deleted and colors are expressed using LEDs.

Taking a liquid crystal display driven by a blue LED and a white LED as an example, one image frame is composed of two subframes, and the lengths of the two subframes are the same.

As the pixels displaying different colors in the display panel 110 are driven at equal intervals, the blue LED and the white LED also operate at equal intervals.

At this time, the interval S1 between the blue LED emitting section in the subframe where the blue LED is driven and the white LED emitting section in the white LED driven subframe is set to be asymmetrical with the interval S2 of the emission section between the video frames.

For example, when the display device 100 displays white, black, and white in three consecutive image frames, all pixels are driven in the image frame displaying white, and blue LEDs and white LEDs are sequentially driven.

In addition, the blue LED and the white LED are sequentially driven without driving all the pixels in the image frame displaying black.

Here, the interval S1 between the section in which the blue LED and the white LED emit light in the video frame displaying white is the section in which the white LED emits light in the image frame displaying white and the section in which the blue LED emits light in the video frame displaying black. The interval between them is set shorter than S2.

Through this, it is possible to prevent a color break up phenomenon occurring at the moment when an image frame is switched, compared to a case in which the interval between the emission sections of the blue LED and the white LED is the same in all subframes.

That is, when the intervals between the emission sections of the blue LED and the white LED are all the same, A for which white is recognized with the naked eye and A' for which black is recognized are not distinguished, but are included in different image frames and adjacent subframes are displayed as one. It is recognized as an image frame and can be recognized as B and B'.

In the present embodiments, in the FSC driving method, the interval S1 between the emission intervals of the subframes in the video frame and the interval S2 between the emission intervals between the video frames are asymmetrically set, and S1 is set shorter than S2 to reduce the increase in luminance due to FSC driving. While maintaining the effect, it is prevented from occurring when the video frame is switched, which is incorrectly recognized by the naked eye.

On the other hand, when one of the light emitting parts is used in white color for FSC driving, a phenomenon (flicker) may occur in the displayed image due to the luminance difference between the light emitting part emitting white color and the light emitting part of a different color. may be

The FSC driving method of the display device 100 according to the present embodiments provides a method for preventing a luminance difference when a white color is included in the light emitting portion.

4 and 5 show a second embodiment of the driving timing of the display device 100 driven by the FSC driving method according to the present embodiments.

Referring to FIG. 4, a liquid crystal display driven by the FSC driving method is shown as an example, and a case of driving a blue LED and a white LED is shown.

An image frame is composed of a first subframe and a second subframe having the same length, and a blue LED is driven in the first subframe and a white LED is driven in the second subframe.

At this time, the white LED is simultaneously driven in the first subframe driving the blue LED.

That is, as shown in 401 of FIG. 4 , both the blue LED and the white LED are driven in the first subframe, and only the white LED is driven in the second subframe.

Therefore, by driving the white LED together at the timing of driving the blue LED, flicker caused by a difference in luminance between the blue LED and the white LED is prevented from occurring.

Referring to FIG. 5 , each pixel in the display panel 110 is driven at equal intervals according to subframes having the same length.

And, accordingly, the blue LED and the white LED are sequentially driven at equal intervals to display colors.

At this time, in the period of driving the blue LED, the white LED is also driven during the same emission period.

Therefore, when the white LED is driven by the FSC driving method, it emits light in the emission period of all subframes.

Through this, it is possible to prevent a decrease in luminance compared to the case where only the blue LED is driven without the white LED and to reduce the luminance difference between the section in which the white LED is driven.

Looking at the portion showing the luminance in each subframe in FIG. 5 , it can be seen that the difference in luminance between the section where the blue LED is driven and the section where the white LED is driven is small.

That is, compared to the case where only the blue LED is driven without the white LED being driven in the section in which the blue LED is driven, the luminance is improved to reduce the luminance difference between the section in which the white LED is driven.

Therefore, in FSC driving in the display device 100, when a color filter of some color is not used and an LED of the corresponding color is used, and a white LED is used to express other colors in which the color filter is disposed, white It helps to prevent flicker caused by the difference in luminance between the LED and the LED displaying a different color.

6 shows a third embodiment of driving timing of the display device 100 driven by the FSC driving method according to the present embodiments, and shows a case in which both the first and second embodiments are applied.

Referring to FIG. 6, a display device 100 driving a blue LED and a white LED is shown as an example, and one image frame is divided into a first subframe and a second subframe.

The lengths of the first subframe and the second subframe are the same, and each pixel disposed on the display panel 110 is driven at equal intervals according to the length of the subframe.

Blue LEDs are driven in the first subframe to display colors, white LEDs are driven in the second subframe to display colors, and images are displayed in sequentially displayed color combinations.

An interval S1 between emission sections of subframes in one image frame is set shorter than an interval S2 between emission sections of another image frame.

For example, the blue LED is driven in the emission period of the first subframe of the first image frame. The emission period of the second subframe is set after the interval S1 from the emission period of the first subframe. Therefore, the white LED is driven after S1 from the emission period of the blue LED.

After driving the white LED in the second subframe of the first image frame, driving the blue LED in the first subframe of the second image frame after an interval S2 longer than S1.

By setting the interval S1 between emission sections in the same video frame to be short and the interval S2 between emission sections in different video frames to be long, color break up that can occur at the moment of video frame switching is prevented. can do.

In addition, in order to prevent flicker caused by a difference in luminance between the blue LED and the white LED, the white LED is driven together in the section where the blue LED is driven.

For example, the blue LED and the white LED are simultaneously driven in the first subframe of the first image frame, and only the white LED is driven in the second subframe of the first image frame.

By driving the white LED together in a period in which the blue LED, which has lower luminance than the white LED, is driven, it is possible to reduce a luminance difference with the white LED driving in the next subframe of the subframe driving the blue LED.

By reducing the luminance difference between the subframe driving the blue LED and the subframe driving the white LED, flicker caused by the luminance difference between the blue LED and the white LED can be prevented.

7 illustrates a process of a method of driving the display device 100 driven by the FSC driving method according to the present embodiments.

Referring to FIG. 7 , the first emitter is driven in the first subframe of the first image frame (S700).

The second light emitting unit is driven in the second subframe of the first image frame after the first interval (S1) from the driving period of the first light emitting unit (S720).

The first light emitting unit is driven in the first subframe of the second image frame after the second interval (S2) from the driving period of the second light emitting unit (S740).

At this time, the first interval S1 and the second interval S2 are set asymmetrically, and the second interval S2 is set longer than the first interval S1.

The second light emitting unit is driven in the second subframe of the second image frame after the first interval (S1) from the period in which the first light emitting unit was driven in the first subframe of the second image frame (S760).

Therefore, the interval S1 between the emission sections of the subframes in the video frame is kept constant and FSC driving is performed, and the interval S2 between the emission sections between different video frames is set longer than S1, thereby preventing color break up during FSC driving. prevent this from happening.

According to the present embodiments, an image frame is composed of a plurality of subframes having the same length and different colors are displayed in each subframe, so that an image can be displayed with a combination of sequentially displayed colors.

At this time, by setting the interval S1 between emission intervals of adjacent subframes in the same image frame to be shorter than the interval S2 between emission intervals of subframes included in another image frame and adjacent to each other, the color breakup phenomenon (Color Break Up ) does not occur.

In addition, in the case of including a light emitting unit emitting white color, the light emitting unit emitting white color is driven together with the driving section of the light emitting unit emitting light in a different color, causing a flickering phenomenon (flicker) due to a luminance difference between the white color emitting unit and the other color emitting unit ) to prevent it.

The above description is merely an example of the technical idea of the present invention, and various modifications and variations can be made to those skilled in the art without departing from the essential characteristics of the present invention. In addition, since the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but are intended to explain, the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed according to the following claims, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

100: display device 110: display panel
120: gate driver 130: data driver
140: controller

Claims (10)

a first light-emitting unit that emits light in a light-emitting section of a first subframe of an N-th image frame; and
A second light emitting unit that emits light in a light emitting section of a second subframe of the Nth image frame and emits light in a color different from that of the first light emitting unit;
The interval between the emission period of the first subframe of the N-th video frame and the emission period of the second subframe of the N-th video frame is the emission period of the last subframe of the N-th video frame and the (N+1)th emission period of the last subframe of the N-th image frame. shorter than the interval between the emission sections of the first subframe of the video frame,
One of the first light emitting part and the second light emitting part emits white light and the other light emits a color other than white;
Among the first light emitting unit and the second light emitting unit, the white light emitting unit emits light in both a light emitting period of a subframe in which the first light emitting unit emits light and a light emitting period of a subframe in which the second light emitting unit emits light. display device.
According to claim 1,
The first light emitting unit and the second light emitting unit are light sources that radiate light to a plurality of pixels disposed on a display panel.
delete delete According to claim 1,
A display device disposed on a display panel and including a plurality of pixels composed of a plurality of subpixels, wherein at least one of the plurality of subpixels included in each pixel is not disposed with a color filter.
According to claim 1,
A display device in which the interval between emission sections of subframes adjacent to each other within the same image frame is constant.
a first light-emitting unit that emits light in a color other than white in a light-emitting section of a first subframe of an image frame; and
A second light-emitting unit that emits white light in a light-emitting period of a first sub-frame and a light-emitting period of a second sub-frame of the image frame;
The second light-emitting unit emits white light simultaneously with a color other than the white of the first light-emitting unit in the light-emitting period of the first sub-frame of the image frame, and emits only white light in the light-emitting period of the second sub-frame. .
driving a first light emitter in a light emission period of a first subframe of an image frame; and
driving a second light emitting unit that emits light in a color different from that of the first light emitting unit in an emission period of a second subframe of the image frame;
The interval between the emission period of the first subframe and the emission period of the second subframe is shorter than the interval between the emission period of the last subframe of the video frame and the emission period of the first subframe of the next video frame;
One of the first light emitting part and the second light emitting part emits white light and the other light emits a color other than white;
Among the first light emitting unit and the second light emitting unit, the white light emitting unit emits light in both a light emitting period of a subframe in which the first light emitting unit emits light and a light emitting period of a subframe in which the second light emitting unit emits light. How to drive the display device.
delete According to claim 8,
When the first light emitting part and the second light emitting part are light sources that radiate light to a plurality of pixels disposed on the display panel, the first light emitting part and the second light emitting part are uniform throughout the display panel in each light emitting section. A method of driving a display device that radiates light in an unobtrusive manner.

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