KR20230032634A - Organic light emitting display device and method thereof - Google Patents

Abstract

The present invention relates to an organic light emitting display device and an operating method thereof. According to one aspect of the present invention, an organic light emitting display device includes: a display panel including pixels; a drive circuit for driving the display panel according to a control signal; and a timing controller which generates a control signal corresponding to an input image. A timing controller amplifies a gradation value of the image signal so that a transistor included in the pixel operates in a saturation region, and adjusts the light emission time (DR) of the pixel corresponding to the amplification of the gradation value, so that the control signal having a reduced duty ration the pixel may be generated. Therefore, it is possible for the organic light emitting display to operate in a saturation region.

Description

Organic light emitting display device and its operating method {ORGANIC LIGHT EMITTING DISPLAY DEVICE AND METHOD THEREOF}

The present invention relates to an organic light emitting display device and an operating method thereof.

A flat panel display device is used as a display device that replaces a cathode ray tube display device due to characteristics such as light weight and thin shape. Representative examples of such a flat panel display include a Liquid Crystal Display (LCD) device and an Organic Light Emitting Diode display (OLED) device. Among them, the organic light emitting display device has an advantage in that it has excellent luminance characteristics and viewing angle characteristics compared to the liquid crystal display device and can be implemented in an ultra-thin type because it does not require a back light. In such an organic light emitting display device, electrons and holes injected into an organic thin film through a cathode and an anode recombine to form excitons, and energy from the formed excitons produces a specific wavelength. Use the phenomena of light.

In the organic light emitting display device, when a difficult image is input as TFT (Thin film transistor) is used, it operates not in the serration area but in the sub-threshold area where the slope is not uniform, which causes a problem in which stains are recognized. is being raised

Korean Patent Registration No. 10-2139693, "Brightness control method, luminance control unit, and organic light emitting display having the same"

An object of the present invention is to provide a technology for enabling an organic light emitting display device to operate in a saturation region.

An object of the present invention is to provide a technology for enabling an organic light emitting display device to operate in a saturation region by amplifying grayscale values of a dark input image.

According to one aspect of the present invention, an organic light emitting display device includes a display panel including pixels; a drive circuit that drives the display panel according to the control signal; and a timing controller configured to generate a control signal corresponding to an input image, wherein the timing controller amplifies a grayscale value ( _gi ) of the image signal so that a transistor included in a pixel operates in a saturation region, Correspondingly, a control signal having a reduced emission time DR of a pixel may be generated.

In an exemplary embodiment, the timing controller may include a reference grayscale value determining module configured to determine a maximum grayscale value among grayscale values of an input image as a reference grayscale value (g _d ); a grayscale value amplifying module that amplifies the grayscale value (gi ) of the input image so that the reference grayscale value (g _d ) becomes the maximum grayscale value (g _m ) set in the pixel _; a light emitting time adjusting module that reduces the light emitting time (DR) of a pixel based on the amplification ratio of a grayscale value; and a control signal generating module generating a control signal based on the amplified grayscale value (g _c ) and the reduced light emission time.

In an embodiment, the reference grayscale value determination module determines the reference grayscale value (g _d ) in units of gate lines shared by a plurality of pixels, and the grayscale value amplifying module determines the grayscale value ( _gi ) of the input image as a gate line. Amplification is performed in units of lines, and the emission time adjustment module may decrease the emission time (DR) of pixels in units of gate lines.

In an embodiment, the reference grayscale value determination module determines the reference grayscale value (g _d ) in units of blocks including a plurality of gate lines shared by a plurality of pixels, and the grayscale value amplifying module determines the grayscale of the input image. The value g _i may be amplified in units of blocks, and the emission time adjustment module may decrease the emission time DR of pixels in units of blocks.

)에 따라 입력 영상의 계조값을 증폭시킬 수 있다.In one embodiment, the grayscale value amplification module is expressed by Equation 1 (

), the grayscale value of the input image can be amplified.

)에 따라 발광 시간을 감소시킬 수 있다.In one embodiment, the light emitting time adjustment module is Equation 2 (

), the emission time can be reduced according to

According to another aspect of the present invention, a display panel including pixels; a drive circuit for driving the display panel according to the control signal; and a timing controller configured to generate a control signal corresponding to an input image, wherein the timing controller controls the gray level value ( _gi) of the image signal to allow a transistor included in a pixel to operate in a saturation region. ) is amplified; and generating a control signal having a reduced emission time (DR) of a pixel corresponding to the grayscale value amplification.

According to an exemplary embodiment of the present invention, an organic light emitting display device can operate in a saturation region.

According to an exemplary embodiment of the present invention, the organic light emitting display device can operate in a saturation region by amplifying a grayscale value of a dark input image.

1 is a block diagram illustrating an organic light emitting display device according to the present invention.
FIG. 2 is a diagram showing an example of an internal block diagram of the image display device of FIG. 1 .
3 is a block diagram of a timing controller according to another embodiment of the present invention.
4 is a diagram for explaining an example of adjusting a grayscale value and a light emission time in the case of a dark input image.
FIG. 5 is a diagram for explaining the operation of a transistor when a grayscale value of an input image is amplified according to an embodiment of the present invention, and FIG. 6 is a diagram for explaining the operation of a transistor when a grayscale value of an input image is amplified.
7 is a diagram for explaining an operating method of a timing controller according to an embodiment of the present invention.

Hereinafter, various embodiments of this document will be described with reference to the accompanying drawings.

Examples and terms used therein are not intended to limit the technology described in this document to specific embodiments, and should be understood to include various modifications, equivalents, and/or substitutes of the embodiments.

In the following description of various embodiments, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the invention, the detailed description will be omitted.

In addition, terms to be described below are terms defined in consideration of functions in various embodiments, and may vary according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout this specification.

In connection with the description of the drawings, like reference numerals may be used for like elements.

Singular expressions may include plural expressions unless the context clearly dictates otherwise.

In this document, expressions such as "A or B" or "at least one of A and/or B" may include all possible combinations of the items listed together.

Expressions such as "first," "second," "first," or "second," may modify the corresponding components regardless of order or importance, and are used to distinguish one component from another. It is used only and does not limit the corresponding components.

When a (e.g., first) element is referred to as being "(functionally or communicatively) coupled to" or "connected to" another (e.g., second) element, that element refers to the other (e.g., second) element. It may be directly connected to the component or connected through another component (eg, a third component).

In this specification, "configured to (or configured to)" means "suitable for," "having the ability to," "changed to" depending on the situation, for example, hardware or software ," can be used interchangeably with "made to," "capable of," or "designed to."

In some contexts, the expression "device configured to" can mean that the device is "capable of" in conjunction with other devices or components.

For example, the phrase "a processor configured (or configured) to perform A, B, and C" may include a dedicated processor (eg, embedded processor) to perform the operation, or by executing one or more software programs stored in a memory device. , may mean a general-purpose processor (eg, CPU or application processor) capable of performing corresponding operations.

Also, the term 'or' means 'inclusive or' rather than 'exclusive or'.

That is, unless otherwise stated or clear from the context, the expression 'x employs a or b' means any one of the natural inclusive permutations.

Terms such as '..unit' and '..group' used below refer to a unit that processes at least one function or operation, and may be implemented by hardware or software, or a combination of hardware and software.

1 is a block diagram illustrating an organic light emitting display device according to the present invention, and FIG. 2 is a diagram showing an example of an internal block diagram of the image display device of FIG. 1 .

Referring to FIG. 1 , an organic light emitting diode display device according to an exemplary embodiment may include a display panel 10 and a panel driver driving the display panel 10 . The panel driver may include a data driver 30 , a gate driver 40 and a timing controller 20 .

The timing controller 20 includes a control signal generator 22 and a data converter 24 . The control signal generator 22 generates data control signals and gate control signals that control driving timings of the data driver 30 and the gate driver 40, respectively, and supplies them to the data driver 30 and the gate driver 40. do. The data converter 24 may process image data and supply the image data to the data driver 30 .

The data driver 30 may convert input image data into image data voltages during the light emitting display period by a data control signal supplied from the timing controller 20 and supply the converted image data voltages to the data line DL of the display panel 10 . Also, the data driver 30 may supply the black data voltage to the data line DL of the display panel 10 during the black display period according to the data control signal supplied from the timing controller 20 .

The gate driver 40 may output a gate signal including a scan signal and an emission control signal to the gate lines GL under the control of the timing controller 20. The gate driver 40 may sequentially supply the signals to the gate lines GL by shifting the gate signals using a shift register.

A plurality of sub-pixels SP may be disposed on the display panel 10 to implement an image. For color implementation, red (R), green (G), and blue (B) sub-pixels SP may be disposed or white sub-pixels SP may be further disposed.

As shown in FIG. 2 , each sub-pixel SP may include a light emitting element EL and a pixel driving circuit for driving the light emitting element EL. The pixel driving circuit may include first to fifth switch TFTs (T1, T2, T3, T4, T5), a driving TFT (DT), and a storage capacitor (Cst). Here, the pixel driving circuit is not limited to the structure of FIG. 2 and can be changed in various ways.

For the first to fifth switch TFTs (T1, T2, T3, T4, T5) and the driving TFT (DT), an amorphous TFT, a polycrystalline TFT, an oxide TFT, or an organic TFT may be used according to the material of the active layer.

The first switch TFT (T1) is controlled by the first scan signal (SCAN1) of the first gate line 142 and applies the data voltage (Vdata) of the data line 178 to the first node during the sampling period after the initialization period. (n1) can be supplied. The second switch TFT (T2) is controlled by the second scan signal (SCAN2) of the second gate line 144, and connects the second node (n2) and the third node (n3) during the sampling period to the driving TFT ( DT) can be connected with a diode. The third switch TFT (T3) is controlled by the emission control signal (EM) of the third gate line 146, and the first node (n1) and the storage capacitor (Cst) through the reference voltage line 152 during the initialization period. may be initialized with the reference voltage (Vref). The fourth switch TFT (T4) is controlled by the light emission control signal (EM) of the third gate line 146, and drives the driving current supplied from the driving TFT (DT) during the light emission period after the sampling period to the light emitting element (EL). can be supplied with The fifth switch TFT T5 is controlled by the second scan signal SCAN2 of the second gate line 144 and may initialize the fourth node n4 to the reference voltage Vref during the sampling period. The driving TFT DT can adjust the current flowing through the light emitting element EL according to the gate-source voltage Vgs stored in the storage capacitor Cst.

The storage capacitor Cst is connected between the first node n1 and the second node n2. The data voltage Vdata compensated for by the threshold voltage Vth of the driving TFT DT may be charged in the storage capacitor Cst. Therefore, since the data voltage Vdata is compensated for by the threshold voltage Vth of the driving TFT DT, the variation in characteristics of the driving TFT DT between pixels can be compensated for.

The light emitting element EL may emit light with an amount of current controlled by the driving TFT DT according to the data voltage Vdata.

3 is a block diagram of a timing controller according to another embodiment of the present invention.

Referring to FIG. 3 , the timing controller 20 may include a reference grayscale value determining module 410 , a grayscale value amplifying module 420 , an emission time adjustment module 430 and a control signal generating module 440 .

The reference grayscale value determination module 410 may determine a reference grayscale value (g _d ) used to amplify the grayscale value so that the transistor included in the pixel operates in the saturation region, based on the grayscale value information of the input image.

In an embodiment, the reference grayscale value determining module 410 may determine a maximum grayscale value among grayscale values of the input image as the reference grayscale value g _d .

In an exemplary embodiment, the reference grayscale value determination module 410 may determine the reference grayscale value g _d in units of gate lines shared by a plurality of cells. Specifically, the reference grayscale value determining module 410 may determine the maximum grayscale value among the grayscale values of the input image corresponding to each gate line as the reference grayscale value g _d .

In an embodiment, the reference grayscale value determination module 410 may determine the reference grayscale value g _d in units of blocks including a plurality of gate lines. Specifically, the reference grayscale value determining module 410 may determine the maximum grayscale value among the grayscale values of the input image corresponding to each block as the reference grayscale value g _d .

The grayscale value amplifying module 420 may amplify the grayscale value of the input image so that the transistors included in the pixels operate in the saturation region. This is because the transistor operates in a sub-threshold region when the gradation value is small, and in this case, the sub-threshold slope is not uniform to avoid image quality defects in which stains are recognized.

In an embodiment, the grayscale value amplifying module 420 may amplify the grayscale values of the input image so that the reference grayscale value becomes the maximum grayscale value set in the pixel.

In an embodiment, the grayscale value amplifying module 420 may amplify grayscale values of an input image according to Equation 1 below.

In an embodiment, the grayscale value amplifying module 420 may amplify grayscale values of the input image corresponding to each gate line based on reference grayscale values determined for each gate line shared by a plurality of pixels.

In an embodiment, the grayscale value amplifying module 420 may amplify grayscale values of the input image corresponding to each block based on the reference grayscale value determined for each block including a plurality of gate lines.

The emission time adjustment module 430 may adjust the emission time of the pixel to decrease corresponding to the amplification of the grayscale value of the input image. This is to obtain the same effect as when the original input image is viewed by reducing the emission time of the pixel corresponding to the grayscale value amplification.

In an embodiment, the emission time adjustment module 430 may adjust the emission time of the pixel by reducing or increasing the duty ration (DR) of the EM perspective controlling the emission period of the pixel.

In an embodiment, the emission time adjustment module 430 may adjust the emission time of the pixel according to Equation 2 below.

Here, gamma (γ) is a value that determines a correlation between brightness of a display and luminance of an image displayed on a screen, and may be set differently for each organic light emitting display device, but 2.2 is generally used.

In an embodiment, when the grayscale values of the input image corresponding to each gate line are amplified, the emission time adjustment module 430 may adjust the emission time of the pixel in units of each data line.

In an embodiment, when the grayscale values of the input image corresponding to each block are amplified, the grayscale value amplifying module 420 may adjust the emission time of the pixel for each block.

The control signal generation module 440 may generate a control signal for controlling the display panel to output an image according to the amplified grayscale value and the adjusted light emission time.

In an exemplary embodiment, the control signal generation module 440 may generate a control signal for controlling the display panel to output an image according to the amplified grayscale value and the adjusted emission time for each gate line or block.

4 is a diagram for explaining an example of adjusting a grayscale value and a light emission time in the case of a dark input image.

4(A) shows a dark input image, that is, an input image having low grayscale values. At this time, the timing controller 20 may determine 128, which is the largest grayscale value among grayscale values of the input image, as a reference grayscale value.

4(B) shows an image in which grayscale values are amplified. This allows the timing controller 20 to amplify the grayscale values of the input image so that 128, which is the largest grayscale value among the grayscale values of the input image, becomes 255, the maximum grayscale value set in the pixel.

FIG. 4(C) shows an image in which the image of FIG. 4(B) is cyan when the emission time is decreased. The timing controller 20 shortens the emission time of the pixel corresponding to the input image in which the grayscale value is amplified, so that the image of FIG. 4 (C) similar to that of FIG. do.

FIG. 5 is a diagram for explaining the operation of a transistor when a grayscale value of an input image is amplified according to an embodiment of the present invention, and FIG. 6 is a diagram for explaining the operation of a transistor when a grayscale value of an input image is amplified.

Referring to FIG. 5 , in the case of an input image having low grayscale values as shown in FIG. 5 (A), TFTs operate in a sub-threshold region as shown in FIG. 5 (B). In this case, since the slope of the sub-threshold is not uniform, a problem in which stains are recognized may occur.

Referring to FIG. 6, when the grayscale values of the input image are amplified but the emission time is shortened as shown in FIG. there is.

Accordingly, it can be confirmed that the operation problem in the sub-threshold area can be solved by operating the TFTs in the saturation area when amplifying the gray level value and adjusting the emission time according to the present invention.

7 is a diagram for explaining an operating method of the timing controller 20 according to an embodiment of the present invention.

Hereinafter, the method illustrated in FIG. 7 will be described below by taking the method performed by the timing controller 20 illustrated in FIG. 3 as an example.

Referring to FIG. 7 , a reference grayscale value is determined in step S710. Specifically, the timing controller 20 may determine a reference grayscale value (g _d ) used to amplify the grayscale value so that the transistor included in the pixel operates in the saturation region, based on grayscale value information of the input image.

In an embodiment, the timing controller 20 may determine a maximum grayscale value among grayscale values of the input image as the reference grayscale value g _d .

In an exemplary embodiment, the timing controller 20 may determine the reference grayscale value g _d in units of gate lines shared by a plurality of cells. Specifically, the timing controller 20 may determine the maximum grayscale value among the grayscale values of the input image corresponding to each gate line as the reference grayscale value g _d .

In an exemplary embodiment, the timing controller 20 may determine the reference grayscale value g _d in units of blocks including a plurality of gate lines. Specifically, the timing controller 20 may determine the maximum grayscale value among the grayscale values of the input image corresponding to each block as the reference grayscale value g _d .

In step S720, grayscale values of the input image are amplified. Specifically, the timing controller 20 may amplify the grayscale value of the input image so that the transistor included in the pixel operates in the saturation region. This is because the transistor operates in a sub-threshold region when the gradation value is small, and in this case, the sub-threshold slope is not uniform to avoid image quality defects in which stains are recognized.

In an embodiment, the timing controller 20 may amplify the grayscale values of the input image so that the reference grayscale value becomes the maximum grayscale value set for the pixel.

In an embodiment, the timing controller 20 may amplify grayscale values of the input image corresponding to each gate line based on reference grayscale values determined for each gate line shared by a plurality of pixels.

In an embodiment, the timing controller 20 may amplify grayscale values of the input image corresponding to each block based on the reference grayscale values determined for each block including a plurality of gate lines.

In step S730, the light emission time of the pixel is adjusted. Specifically, the timing controller 20 may adjust the emission time of the pixel to decrease corresponding to the amplification of the grayscale value of the input image. This is to obtain the same effect as when the original input image is viewed by reducing the emission time of the pixel corresponding to the grayscale value amplification.

In one embodiment, the timing controller 20 may adjust the emission time of the pixel by reducing or increasing the duty ration (DR) of the EM phase controlling the emission period of the pixel.

In an embodiment, the timing controller 20 may adjust the emission time of the pixel in units of each data line when the grayscale values of the input image corresponding to each gate line are amplified.

In an embodiment, the timing controller 20 may adjust the emission time of the pixel in units of each block when the grayscale values of the input image corresponding to each block are amplified.

In step S740, the display panel is driven. The timing controller 20 may generate a control signal for controlling the display panel to output an image according to the amplified grayscale value and the adjusted emission time. The panel driver may drive the display panel to output an image according to a control signal.

In one embodiment, the timing controller 20 may generate a control signal for controlling the display panel to output an image according to the amplified grayscale value and the adjusted emission time for each gate line or block.

In addition, for convenience of description, although step S has been shown and described as being performed prior to step S, it is obvious that it is not limited thereto and both may be performed simultaneously or one may be performed prior to the other.

The method according to the embodiment may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer readable medium. The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination. Program commands recorded on the medium may be specially designed and configured for the embodiment or may be known and usable to those skilled in computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic media such as floptical disks. - includes hardware devices specially configured to store and execute program instructions, such as magneto-optical media, and ROM, RAM, flash memory, and the like. Examples of program instructions include high-level language codes that can be executed by a computer using an interpreter, as well as machine language codes such as those produced by a compiler. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

Software may include a computer program, code, instructions, or a combination of one or more of the foregoing, which configures a processing device to operate as desired or processes independently or collectively. The device can be commanded. Software and/or data may be any tangible machine, component, physical device, virtual equipment, computer storage medium or device, intended to be interpreted by or provide instructions or data to a processing device. , or may be permanently or temporarily embodied in a transmitted signal wave. Software may be distributed on networked computer systems and stored or executed in a distributed manner. Software and data may be stored on one or more computer readable media.

As described above, although the embodiments have been described with limited drawings, those skilled in the art can make various modifications and variations from the above description. For example, the described techniques may be performed in an order different from the method described, and/or components of the described system, structure, device, circuit, etc. may be combined or combined in a different form than the method described, or other components may be used. Or even if it is replaced or substituted by equivalents, appropriate results can be achieved.

Therefore, other implementations, other embodiments, and equivalents of the claims are within the scope of the following claims.

Claims (12)

a display panel including pixels;
a drive circuit for driving the display panel according to a control signal; and
A timing controller configured to generate the control signal corresponding to an input image,
The timing controller,
Generating the control signal in which a gradation value ( _gi ) of the image signal is amplified so that a transistor included in the pixel operates in a saturation region, and a light emission time (DR) of the pixel is reduced corresponding to the gradation value amplification. , organic light emitting display device.
According to claim 1,
The timing controller,
a reference grayscale value determining module for determining a maximum grayscale value among the grayscale values of the input image as a reference grayscale value (g _d );
a grayscale value amplifying module _that amplifies the grayscale value (gi ) of the input image so that the reference grayscale value (g _d ) becomes the maximum grayscale value (g _m ) set in the pixel;
a light emitting time adjustment module that reduces the light emitting time (DR) of the pixel based on the amplification ratio of the grayscale value; and
and a control signal generation module configured to generate the control signal based on the amplified grayscale value (g _c ) and the reduced emission time.
According to claim 2,
The reference grayscale value determination module determines the reference grayscale value (g _d ) in units of gate lines shared by a plurality of pixels;
The grayscale value amplifying module amplifies the grayscale value g _i of the input image in units of the gate line;
The organic light emitting display device of claim 1 , wherein the emission time adjusting module reduces the emission time DR of the pixel in units of the gate line.
According to claim 2,
The reference grayscale value determination module determines the reference grayscale value (g _d ) in units of blocks including a plurality of gate lines shared by a plurality of pixels;
The grayscale value amplifying module amplifies the grayscale value g _i of the input image in units of blocks;
The organic light emitting display device of claim 1 , wherein the emission time adjusting module reduces the emission time (DR) of the pixel in units of blocks.
According to claim 2,
The grayscale value amplifying module
Equation 1 (

), the organic light emitting display device characterized in that the grayscale value of the input image is amplified.
According to claim 2,
The emission time adjustment module
Equation 2 (

), the organic light emitting display device characterized in that the emission time is reduced according to.
a display panel including pixels; a drive circuit for driving the display panel according to a control signal; and a timing controller configured to generate the control signal corresponding to an input image.
the timing controller,
amplifying the grayscale value g _i of the image signal so that the transistor included in the pixel operates in a saturation region; and
and generating the control signal in which the emission time (DR) of the pixel is reduced corresponding to the grayscale value amplification.
According to claim 7,
The step of amplifying the gradation value (g _i ) of the image signal,
determining a maximum grayscale value among grayscale values of the input image as a reference grayscale value (g _d ); and
amplifying the grayscale value ( _gi ) of _the input image so that the reference grayscale value (g d ) becomes the maximum grayscale value (g _m ) set in the pixel;
Generating the control signal,
reducing an emission time (DR) of the pixel based on an amplification ratio of the grayscale value; and
and generating the control signal based on the amplified grayscale value (g _c ) and the reduced emission time.
According to claim 8,
The determining of the reference grayscale value (g _d ) may include determining the reference grayscale value (g _d ) in units of gate lines shared by a plurality of pixels;
The amplifying the grayscale value g _i may include amplifying the grayscale value g _i of the input image in units of the gate line;
The reducing of the light emitting time (DR) of the pixel may include reducing the light emitting time (DR) of the pixel in units of the gate line.
According to claim 8,
In the determining of the reference grayscale value (g _d ), the reference grayscale value (g _d ) is determined in units of blocks each including a plurality of gate lines shared by a plurality of pixels;
The step of amplifying the grayscale value (gi ₎ may include amplifying the grayscale value (g _i ) of the input image in units of blocks;
The reducing of the emission time (DR) of the pixel may include reducing the emission time (DR) of the pixel in units of blocks.
According to claim 8,
The step of amplifying the gradation value g _i is
Equation 1 (

), characterized in that the grayscale value of the input image is amplified.
According to claim 8,

The step of reducing the light emission time (DR) of the pixel,
Equation 2 (

), characterized in that to reduce the light emission time according to, the method.

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