Patent Description:
A display apparatus may include a display panel and a display panel driver. The display panel includes a plurality of gate lines, a plurality of data lines and a plurality of pixels. The display panel driver includes a gate driver, a data driver, and a driving controller. The gate driver outputs gate signals to the gate lines. The data driver outputs data voltages to the data lines. The driving controller controls the gate driver and the data driver.

The driving controller may determine a driving frequency of the display panel according to input image data. When an event generated at the display apparatus is not transmitted to the driving controller fast in a low frequency driving mode, an image transmission may be delayed. For example, when a touch event of the display panel is generated in the low frequency driving mode, an immediate image transmission may be required. When the delay of the touch event occurs in <NUM> driving, the image transition may be delayed (e.g., for about a second) so that a user may perceive the image transition as a display defect.

Aspects of some embodiments of the present inventive concept relate to a display apparatus and a method of driving the display apparatus. For example, some embodiments of the present inventive concept relate to a display apparatus determining a touch event fast in a low frequency driving method to prevent or reduce a delay of an image transition and a method of driving the display apparatus.

Aspects of some embodiments of the present inventive concept include a display apparatus that may be capable of preventing or reducing a delay of an image transition, when a touch event is generated, to enhance a display quality.

Aspects of some embodiments of the present inventive concept may also include a method of driving the above-mentioned display apparatus.

According to some embodiments of the present inventive concept, there is provided a display apparatus according to claims <NUM> and a display apparatus according to claim <NUM>.

Optional features of the display device are provided in claims <NUM> to <NUM>.

According to some embodiments of the present inventive concept, there is provided a method of driving a display apparatus according to claim <NUM>. Optional features of the method are set out in claims <NUM> to <NUM>.

The above and other features of the invention are set out in the appended claims.

The above and other features and aspects of the present inventive concept will become more apparent by describing in detail aspects of some embodiments thereof with reference to the accompanying drawings, in which:.

Hereinafter, aspects of some embodiments of the present inventive concept will be explained in more detail with reference to the accompanying drawings.

<FIG> is a block diagram illustrating a display apparatus according to some embodiments of the present inventive concept.

Referring to <FIG>, the display apparatus includes a display panel <NUM> and a display panel driver. The display panel driver includes a driving controller <NUM>, a gate driver <NUM>, a gamma reference voltage generator <NUM> and a data driver <NUM>. The display apparatus further includes a touch driver <NUM>. The display apparatus further includes a host <NUM>.

For example, the driving controller <NUM> and the data driver <NUM> may be integrally formed. For example, the driving controller <NUM>, the gamma reference voltage generator <NUM> and the data driver <NUM> may be integrally formed. A driving module including at least the driving controller <NUM> and the data driver <NUM> may be referred to as a timing controller embedded data driver (TED).

The display panel <NUM> includes a display region and a peripheral region adjacent to the display region.

For example, the display panel <NUM> may be an organic light emitting diode display panel including organic light emitting diodes. Alternatively, the display panel <NUM> may be a liquid crystal display panel including liquid crystal molecules.

The display panel <NUM> includes a plurality of gate lines GL, a plurality of data lines DL, and a plurality of pixels electrically connected to the gate lines GL and the data lines DL. The gate lines GL extend in a first direction D1 and the data lines DL extend in a second direction D2 crossing the first direction D1.

According to some embodiments, the display panel <NUM> may be a touch screen panel perceiving a touch event.

The driving controller <NUM> receives input image data IMG and an input control signal CONT from the host <NUM>. The input image data IMG may include red image data, green image data and blue image data. The input image data IMG may include white image data. The input image data IMG may include magenta image data, yellow image data and cyan image data. The input control signal CONT may include a master clock signal and a data enable signal. The input control signal CONT may further include a vertical synchronizing signal and a horizontal synchronizing signal.

The driving controller <NUM> generates a first control signal CONT1, a second control signal CONT2, a third control signal CONT3 and a data signal DATA based on the input image data IMG and the input control signal CONT.

The driving controller <NUM> generates the first control signal CONT1 for controlling an operation of the gate driver <NUM> based on the input control signal CONT, and outputs the first control signal CONT1 to the gate driver <NUM>. The first control signal CONT1 may include a vertical start signal and a gate clock signal.

The driving controller <NUM> generates the second control signal CONT2 for controlling an operation of the data driver <NUM> based on the input control signal CONT, and outputs the second control signal CONT2 to the data driver <NUM>. The second control signal CONT2 may include a horizontal start signal and a load signal.

The driving controller <NUM> generates the data signal DATA based on the input image data IMG. The driving controller <NUM> outputs the data signal DATA to the data driver <NUM>. According to some embodiments, the driving controller <NUM> may compensate the input image data IMG to generate the data signal DATA.

The driving controller <NUM> generates the third control signal CONT3 for controlling an operation of the gamma reference voltage generator <NUM> based on the input control signal CONT, and outputs the third control signal CONT3 to the gamma reference voltage generator <NUM>.

The gate driver <NUM> generates gate signals driving the gate lines GL in response to the first control signal CONT1 received from the driving controller <NUM>. The gate driver <NUM> outputs the gate signals to the gate lines GL. For example, the gate driver <NUM> may sequentially output the gate signals to the gate lines GL. For example, the gate driver <NUM> may be mounted on the display panel <NUM>. For example, the gate driver <NUM> may be integrated on the display panel <NUM>.

The gamma reference voltage generator <NUM> generates a gamma reference voltage VGREF in response to the third control signal CONT3 received from the driving controller <NUM>. The gamma reference voltage generator <NUM> provides the gamma reference voltage VGREF to the data driver <NUM>. The gamma reference voltage VGREF has a value corresponding to a level of the data signal DATA.

According to some embodiments, the gamma reference voltage generator <NUM> may be located in the driving controller <NUM>, or in the data driver <NUM>.

The data driver <NUM> receives the second control signal CONT2 and the data signal DATA from the driving controller <NUM>, and receives the gamma reference voltages VGREF from the gamma reference voltage generator <NUM>. The data driver <NUM> converts the data signal DATA into data voltages having an analog type using the gamma reference voltages VGREF. The data driver <NUM> outputs the data voltages to the data lines DL.

The touch driver <NUM> determines a touch event of the display panel <NUM>. The touch driver <NUM> generates a touch interrupt signal TINT representing an occurrence of the touch event and a touch coordinate signal TC representing coordinates of a touch position. The touch driver <NUM> outputs the touch interrupt signal TINT and the touch coordinate signal TC to the host <NUM>. In addition, the touch driver <NUM> outputs the touch interrupt signal TINT to the driving controller <NUM>. Thus, according to some embodiments, the driving controller <NUM> may include an input port receiving the touch interrupt signal TINT from the touch driver <NUM>.

The host <NUM> outputs the input image data IMG and the input control signal CONT to the driving controller <NUM>.

The host <NUM> receives the touch interrupt signal TINT and the touch coordinate signal TC from the touch driver <NUM>. The host <NUM> may change the input image data IMG to change a display image of the display panel <NUM> in response to the touch interrupt signal TINT and the touch coordinate signal TC.

<FIG> is a block diagram illustrating the driving controller <NUM> of <FIG>. <FIG> is a table illustrating an example flicker lookup table as shown in <FIG>. Referring to <FIG>, the display panel <NUM> may be driven in a normal driving mode and a low frequency driving mode. In the normal driving mode, the display panel <NUM> may be driven in a normal driving frequency. In the low frequency driving mode, the display panel <NUM> may be driven in a driving frequency less than the normal driving frequency.

When the input image data represent a video image, the display panel <NUM> is driven in the normal driving mode. When the input image data represent a still image, the display panel is driven in the low frequency driving mode. For example, when the display apparatus is operated in the always on mode, the display panel may be driven in the low frequency driving mode.

The driving controller <NUM> may include a still image determiner <NUM>, a driving frequency determiner <NUM> and a flicker lookup table <NUM>.

The still image determiner <NUM> may determine whether the input image data IMG is a still image or a video image. The still image determiner <NUM> may output a flag SF representing whether the input image data IMG is the still image or the video image to the driving frequency determiner <NUM>. For example, when the input image data IMG is the still image, the still image determiner <NUM> may output the flag SF of <NUM> to the driving frequency determiner <NUM>. When the input image data IMG is the video image, the still image determiner <NUM> may output the flag SF of <NUM> to the driving frequency determiner <NUM>. When the display panel <NUM> is operated in always on mode, the still image determiner <NUM> may output the flag SF of <NUM> to the driving frequency determiner <NUM>.

When the flag SF is <NUM>, the driving frequency determiner <NUM> may drive the display panel <NUM> in the low frequency driving mode. When the flag SF is <NUM>, the driving frequency determiner <NUM> may drive the display panel <NUM> in the normal driving mode.

The driving frequency determiner <NUM> may refer the flicker lookup table <NUM> to determine a low driving frequency. The flicker lookup table <NUM> may include a flicker value according to a grayscale value of the input image data IMG. For example, the flicker lookup table <NUM> may store a minimum driving frequency in a condition that the difference of the luminance of the writing frame and the luminance of the holding frame does not exceed a just noticeable difference for the grayscale value of the input image data.

In <FIG>, the flicker lookup table may have a value of <NUM> for the grayscale values of <NUM>, <NUM> and <NUM>. Herein the value of <NUM> of the flicker lookup table may represent the driving frequency of <NUM>. In <FIG>, the flicker lookup table may have a value of <NUM> for the grayscale values of <NUM>, <NUM> and <NUM>. Herein the value of <NUM> of the flicker lookup table may represent the driving frequency of <NUM>. In <FIG>, the flicker lookup table may have a value of <NUM> for the grayscale values of <NUM> to <NUM>. Herein the value of <NUM> of the flicker lookup table may represent the driving frequency of <NUM>. In <FIG>, the flicker lookup table may have a value of <NUM> for the grayscale values of <NUM> to <NUM>. Herein the value of <NUM> of the flicker lookup table may represent the driving frequency of <NUM>. In <FIG>, the flicker lookup table may have a value of <NUM> for the grayscale values of <NUM> to <NUM>.

<FIG> is a timing diagram illustrating input and output signals of a display apparatus according to a comparative embodiment;.

Referring to <FIG>, the driving controller <NUM> may generate the data signal DATA (OUTPUT IMAGE) based on the input image data IMG (INPUT IMAGE).

The input image data IMG (INPUT IMAGE) may include input frame images. The data signal DATA (OUTPUT IMAGE) may include output frame images.

A frame may be defined by a vertical synchronizing signal VSYNC. In <FIG>, the frame is defined by a time duration between adjacent rising edges of the vertical synchronizing signal VSYNC.

When an input data enable signal IDE has an active level, the input image data INPUT IMAGE may be inputted. When an output data enable signal ODE has an active level, the data signal OUTPUT IMAGE may be outputted.

The input data enable signal IDE may be activated in all of the frames in <FIG>. In contrast, the output data enable signal ODE may be activated in not all of the frames in <FIG>. The output data enable signal ODE may be activated in a writing frame of the low frequency driving mode and inactivated in a holding frame of the low frequency driving mode.

The input image data INPUT IMAGE during first to third frames F1 to F3 may be respectively A, B and C. The input image data INPUT IMAGE during the first to third frames F1 to F3 are different from one another so that the driving controller <NUM> may determine the input image data INPUT IMAGE during the first to third frames F1 to F3 as the movie image. Thus, during the first to third frames F1 to F3, the data signal OUTPUT IMAGE is driven in a relatively high frequency (e.g. <NUM>).

The input image data INPUT IMAGE of a fourth frame F4 is same as the input image data INPUT IMAGE of the third frame F3 so that the driving controller <NUM> may determine the input image data INPUT IMAGE of the fourth frame F4 as the still image.

The input image data INPUT IMAGE during fifth to seventh frames F5 to F7 are same as the input image data INPUT IMAGE of the fourth frame F4 so that the driving controller <NUM> may determine the input image data INPUT IMAGE during the fifth to seventh frames F5 to F7 as the still image.

When the input image data (INPUT IMAGE) represent the movie image, the display panel <NUM> is driven in the normal driving mode. When the input image data INPUT IMAGE represent the still image, the display panel <NUM> is driven in the low frequency driving mode.

According to some embodiments, the driving frequency (e.g. <NUM>) in the low frequency driving mode may be half of the driving frequency (e.g. <NUM>) in the normal driving mode. Thus, the writing frame and the holding frame may be alternately arranged in the low frequency driving mode.

A touch event may involve a request to transition between a video and a still image. In this way, the touch event is a request to transition between the low frequency and normal driving modes. For example, when a video is being display, a touch input is a request to display a still image, or a request to transition from the normal driving mode to the low frequency driving mode. Similarly, when a still image is being display, a touch input is a request to display a video image, or a request to transition from the low frequency driving mode to the normal driving mode. As discussed below, the latter case is the most likely to cause image defects noticeable by a user.

In <FIG>, a touch event occurs on the display panel <NUM> in the seventh frame F7. A sensing clock signal SENSING CLOCK is a signal for sensing the touch event. A frequency of the sensing clock signal SENSING CLOCK may be different from a frequency of the vertical synchronizing signal VSYNC. In <FIG>, for example, the frequency of the sensing clock signal SENSING CLOCK may be greater than the frequency of the vertical synchronizing signal VSYNC by three times.

When the touch event occurs on the display panel <NUM>, the touch driver <NUM> detects the touch event. When the touch event occurs, a related-art touch driver may output the touch interrupt signal TINT and the touch coordinate signal TC to the host <NUM>.

The host <NUM> may change the input image data INPUT IMAGE to respond to the touch event. The host <NUM> may change the input image data INPUT IMAGE based on the touch interrupt signal TINT and the touch coordinate signal TC and output the input image data INPUT IMAGE to the driving controller <NUM>.

A first delay DY1 may be generated from a time point of detecting the touch event to a time point of generating the touch interrupt signal TINT. A second delay DY2 may be generated from the time point of generating the touch interrupt signal TINT to a time point of generating the touch coordinate signal TC. A third delay DY3 may be generated from the time point of generating the touch coordinate signal TC to a time point of completely transmitting the touch coordinate signal TC to the host <NUM>.

In a related-art display apparatus, the driving controller <NUM> may receive the touch event from the host <NUM> so that the driving controller <NUM> perceives the touch event after the first delay DY1, the second delay DY2 and the third delay DY3.

In <FIG>, the touch event may occur in an early time point of the seven frame F7 and the host <NUM> may perceive the touch event in a late time point of the seven frame F7 due to the delay.

When the host <NUM> perceives the touch event in the late time point of the seven frame F7, the host <NUM> may change the input image data of an eighth frame F8 to "D. " Because the input image data (D) of the eighth frame F8 is different from the input image data (C) of the seventh frame F7, the driving controller <NUM> determines the input image data as the movie image in the eighth frame F8 and the driving controller <NUM> drives the display apparatus in the normal driving mode (a high frequency driving mode) from a ninth frame F9. As a result, although the touch event occurs in the seventh frame F7, the display panel <NUM> is driven in the low frequency driving mode until the eighth frame F8. In the eighth frame F8, the output image is output in the driving frequency of the low frequency driving mode so that the output image of the eight frame F8 is not D but C due to the data delay.

In the low frequency driving mode, a cycle of refreshing the image may be long. Accordingly, when the touch event occurs in the seventh frame F7 and a changed image E is displayed in the ninth frame F9, a user may perceive the delay of the image transition.

<FIG> is a timing diagram illustrating input and output signals of a display apparatus according to a comparative embodiment. <FIG> represents a case worse than a case of <FIG>.

Referring to <FIG>, the input image data INPUT IMAGE during first to third frames F1 to F3 may be respectively A, B and C. The input image data INPUT IMAGE during the first to third frames F1 to F3 are different from one another so that the driving controller <NUM> may determine the input image data INPUT IMAGE during the first to third frames F1 to F3 as the movie image. Thus, during the first to third frames F1 to F3, the data signal OUTPUT IMAGE is driven in a relatively high frequency (e.g. <NUM>).

In <FIG>, a touch event occurs on the display panel <NUM> in the seventh frame F7.

In <FIG>, the touch event may occur in a medium time point of the seven frame F7 and the host <NUM> may perceive the touch event in an early time point of the eighth frame F8 due to the delay.

When the host <NUM> perceives the touch event in the early time point of the eighth frame F8, the host <NUM> may change the input image data of a ninth frame F9 to "D. " Because the input image data (C) of the eighth frame F8 is the same as the input image data (C) of the seventh frame F7, the driving controller <NUM> determines the input image data as the still image in the eighth frame F8 and the driving controller <NUM> drives the display apparatus in the low frequency driving mode in the eighth frame F8. Because the input image data (D) of the ninth frame F9 is different from the input image data (C) of the eighth frame F8, the driving controller <NUM> determines the input image data as the movie image in the ninth frame F9 and the driving controller <NUM> drives the display apparatus in the normal driving mode (a high frequency driving mode) from a tenth frame F10. As a result, although the touch event occurs in the seventh frame F7, the display panel <NUM> is driven in the low frequency driving mode until the ninth frame F9.

In the low frequency driving mode, a cycle of refreshing the image may be long. Accordingly, when the touch event occurs in the seventh frame F7 and a changed image E is displayed in the tenth frame F10, a user may perceive the delay of the image transition and the delay of the image transition in <FIG> may be longer than the delay of the image transition in <FIG>.

<FIG> is a timing diagram illustrating input and output signals of the display apparatus of <FIG>. In <FIG>, the touch driver <NUM> directly outputs the touch interrupt signal TINT to the driving controller <NUM> unlike the comparative embodiments in <FIG> and <FIG>.

When the touch event occurs on the display panel <NUM>, the touch driver <NUM> detects the touch event. When the touch event occurs, a related-art touch driver may output the touch interrupt signal TINT and the touch coordinate signal TC only to the host <NUM>. In contrast, when the touch event occurs, the touch driver <NUM> according to some embodiments outputs the touch interrupt signal TINT to the host <NUM> and the driving controller <NUM>.

According to some embodiments, the driving controller receives the touch event from the touch driver <NUM> before receiving the touch event from the host <NUM> so that the driving controller <NUM> perceives the touch event only after the first delay DY1.

In <FIG>, the touch event may occur in an early time point of the seven frame F7 and the host <NUM> may perceive the touch event in a late time point of the seventh frame F7 and the driving controller <NUM> may perceive the touch event in a medium time point of the seventh frame F7 due to the delay.

When the host <NUM> perceives the touch event in the late time point of the seventh frame F7, the host <NUM> may change the input image data of a eighth frame F8 to "D" same as in the comparative embodiment of <FIG>. Because the related-art driving controller <NUM> may not receive the touch event in advance, the related-art driving controller <NUM> may compare the input image data of the eighth frame F8 and the input image data of the seventh frame F7 and determine the input image data as the movie image in the eighth frame F8. The related-art driving controller <NUM> may drive the display panel <NUM> in the normal driving mode from the ninth frame F9.

However, according to some embodiments, because the driving controller <NUM> receives the touch event from the touch driver <NUM> in advance, the driving controller <NUM> may drive the display panel <NUM> in the normal driving mode from the eighth frame F8. In the comparative embodiment of <FIG>, the output image C of the eighth frame F8 which is different from the input image data D of the eighth frame F8 is outputted. However, in the present example embodiment of <FIG>, the output image D of the eighth frame F8 which is same as the input image data D of the eighth frame F8 is outputted so that the delay of the image transition may be prevented or reduced.

When the display panel <NUM> is driven in the low frequency driving mode and the touch event is perceived by the driving controller <NUM>, the driving controller <NUM> drives the display panel <NUM> in the normal driving mode in a right next frame of a frame when the touch event is perceived.

According to some embodiments, the touch driver <NUM> directly outputs the touch interrupt signal TINT representing the occurrence of the touch event to the driving controller <NUM> so that the driving controller <NUM> may perceive the touch event immediately.

The driving controller <NUM> may determine the touch event immediately so that the display defect due to the delay of the image transition in the low frequency driving mode may be prevented or reduced. Therefore, the display quality of the display panel <NUM> may be enhanced.

<FIG> is a timing diagram illustrating input and output signals of a display apparatus according to some embodiments of the present inventive concept.

The display apparatus and the method of driving the display apparatus according to the present example embodiment is substantially the same as the display apparatus and the method of driving the display apparatus of the previous example embodiment explained referring to <FIG> and <FIG> except for an output timing of the touch interrupt signal. Thus, the same reference numerals will be used to refer to the same or like parts as those described in the previous example embodiment of <FIG> and <FIG> and any repetitive explanation concerning the above elements will be omitted.

Referring to <FIG> and <FIG>, the display apparatus includes a display panel <NUM> and a display panel driver. The display panel driver includes a driving controller <NUM>, a gate driver <NUM>, a gamma reference voltage generator <NUM> and a data driver <NUM>. The display apparatus further includes a touch driver <NUM>. The display apparatus further includes a host <NUM>.

The input image data INPUT IMAGE during the fifth to seventh frames F5 to F7 are same as the input image data INPUT IMAGE of the fourth frame F4 so that the driving controller <NUM> may determine the input image data INPUT IMAGE during the fifth to seventh frames F5 to F7 as the still image.

According to some embodiments, the touch driver <NUM> may output the touch interrupt signal TINT to the driving controller <NUM> after a predetermined time delay DYT. When the touch driver <NUM> immediately outputs the touch interrupt signal TINT to the driving controller <NUM>, the driving controller <NUM> may perceive the occurrence of the touch event prior to the host <NUM>. Accordingly, when the driving controller <NUM> perceives the occurrence of the touch event prior to the host <NUM>, an unexpected display defect of the display image of the display panel <NUM> may be generated or the driving mode of the display panel <NUM> is converted to the normal driving mode earlier than a desired frame so that the power consumption of the display apparatus may be increased. Thus, the touch driver <NUM> may output the touch interrupt signal TINT to the driving controller <NUM> after the predetermined time delay DYT and the predetermined time delay DYT may be properly adjusted considering the display defect and the power consumption of the display apparatus.

For example, the predetermined time delay DYT may adjust the timing of the touch interrupt signal TINT such that the touch interrupt signal TINT is simultaneously transmitted to the driving controller <NUM> and the host <NUM>.

For example, the predetermined time delay DYT may adjust the timing of the touch interrupt signal TINT such that the touch interrupt signal TINT is outputted to the driving controller <NUM> at a falling edge of the touch coordinate signal TC.

The host <NUM> may change the input image data INPUT IMAGE in response to the touch event. The host <NUM> may change the input image data INPUT IMAGE based on the touch interrupt signal TINT and the touch coordinate signal TC and output the changed input image data INPUT IMAGE to the driving controller <NUM>.

In <FIG>, the touch event may be occurred in an early time point of the seven frame F7 and the host <NUM> may perceive the touch event in a late time point of the seventh frame F7 and the driving controller <NUM> may perceive the touch event in a late time point of the seventh frame F7 due to the delay.

When the host <NUM> perceives the touch event in the late time point of the seventh frame F7, the host <NUM> may change the input image data of a eighth frame F8 to "D" same as in the comparative embodiment of <FIG>. Because a related-art driving controller <NUM> may not receive the touch event in advance, the related-art driving controller <NUM> may compare the input image data of the eighth frame F8 and the input image data of the seventh frame F7 and determine the input image data as the movie image in the eighth frame F8. The related-art driving controller <NUM> may drive the display panel <NUM> in the normal driving mode from the ninth frame F9.

The display apparatus and the method of driving the display apparatus according to the present example embodiment is substantially the same as the display apparatus and the method of driving the display apparatus of the previous example embodiment explained referring to <FIG> and <FIG> except that the display apparatus includes a button controller. Thus, the same reference numerals will be used to refer to the same or like parts as those described in the previous example embodiment of <FIG> and <FIG> and any repetitive explanation concerning the above elements will be omitted.

Referring to <FIG>, <FIG>, <FIG> and <FIG>, the display apparatus includes a display panel <NUM> and a display panel driver. The display panel driver includes a driving controller <NUM>, a gate driver <NUM>, a gamma reference voltage generator <NUM> and a data driver <NUM>. The display apparatus further includes a host <NUM>. The display apparatus further includes a button controller <NUM>. Although not shown in figures, the display apparatus may further include the touch driver <NUM> of <FIG>. Alternatively, the display apparatus may not include the touch driver <NUM> of <FIG>.

The button controller <NUM> determines a button input event of the display apparatus. The button controller <NUM> generates a button interrupt signal BINT representing an occurrence of the button input event at an input button of the display apparatus. The button controller <NUM> outputs the button interrupt signal BINT to the host <NUM>. In addition, the button controller <NUM> outputs the button interrupt signal BINT to the driving controller <NUM>. Thus, according to some embodiments, the driving controller <NUM> may include an input port receiving the button interrupt signal BINT from the button controller <NUM>.

The host <NUM> receives the button interrupt signal BINT from the button controller <NUM>. The host <NUM> may change the input image data IMG to change a display image of the display panel <NUM> in response to the button interrupt signal BINT.

The display panel <NUM> may be driven in a normal driving mode and a low frequency driving mode. In the normal driving mode, the display panel <NUM> may be driven in a normal driving frequency. In the low frequency driving mode, the display panel <NUM> may be driven in a driving frequency less than the normal driving frequency.

When the button input event occurs, the button controller <NUM> detects the button input event. When the button input event occurs, a related-art button controller may output the button interrupt signal BINT only to the host <NUM>. In contrast, when the button input event occurs, the button controller <NUM> according to some embodiments outputs the button interrupt signal BINT to the host <NUM> and the driving controller <NUM>.

According to some embodiments, the driving controller receives the button input event from the button controller <NUM> before receiving the button input event from the host <NUM> so that the driving controller <NUM> perceives the button input event only after the first delay DY1 of <FIG>.

When the display panel <NUM> is driven in the low frequency driving mode and the button input event is perceived by the driving controller <NUM>, the driving controller <NUM> drives the display panel <NUM> in the normal driving mode in a right next frame of a frame when the button input event is perceived.

According to some embodiments, the button controller <NUM> directly outputs the button interrupt signal BINT representing the occurrence of the button input event to the driving controller <NUM> so that the driving controller <NUM> may perceive the button input event immediately.

The driving controller <NUM> may determine the button input event immediately so that the display defect due to the delay of the image transition in the low frequency driving mode may be prevented or reduced. Therefore, the display quality of the display panel <NUM> may be enhanced.

<FIG> is a block diagram illustrating a display apparatus according to some embodiments of the present inventive concept. <FIG> is a circuit diagram illustrating a pixel of a display panel of <FIG>. <FIG> is a timing diagram illustrating signals applied to the pixel of the display panel of <FIG>. <FIG> is a timing diagram illustrating signals applied to the pixel of the display panel of <FIG> in a low frequency driving mode.

The display apparatus and the method of driving the display apparatus according to the present example embodiment is substantially the same as the display apparatus and the method of driving the display apparatus of the previous example embodiment explained referring to <FIG> and <FIG> except for the structures of the display panel and the emission driver. Thus, the same reference numerals will be used to refer to the same or like parts as those described in the previous example embodiment of <FIG> and <FIG> and any repetitive explanation concerning the above elements will be omitted.

Referring to <FIG>, <FIG>, <FIG> and <FIG>, the display apparatus includes a display panel <NUM> and a display panel driver. The display panel driver includes a driving controller <NUM>, a gate driver <NUM>, a gamma reference voltage generator <NUM> and a data driver <NUM>. The display apparatus may further include an emission driver <NUM>. The display apparatus further includes a touch driver <NUM>. The display apparatus further includes a host <NUM>.

The display panel <NUM> includes a plurality of gate lines GWPL, GWNL, GIL and GBL, a plurality of data lines DL, a plurality of emission lines EL and a plurality of pixels electrically connected to the gate lines GWPL, GWNL, GIL and GBL, the data lines DL and the emission lines EL. The gate lines GWPL, GWNL, GIL and GBL may extend in a first direction D1, the data lines DL may extend in a second direction D2 crossing the first direction D1 and the emission lines EL may extend in the first direction D1.

The driving controller <NUM> generates a first control signal CONT1, a second control signal CONT2, a third control signal CONT3, a fourth control signal CONT4 and a data signal DATA based on the input image data IMG and the input control signal CONT.

The emission driver <NUM> generates emission signals to drive the emission lines EL in response to the fourth control signal CONT4 received from the driving controller <NUM>. The emission driver <NUM> may output the emission signals to the emission lines EL.

The touch driver <NUM> may determine a touch event of the display panel <NUM>. The touch driver <NUM> may generate a touch interrupt signal TINT representing an occurrence of the touch event and a touch coordinate signal TC representing coordinates of a touch position. The touch driver <NUM> may output the touch interrupt signal TINT and the touch coordinate signal TC to the host <NUM>. In addition, the touch driver <NUM> may output the touch interrupt signal TINT to the driving controller <NUM>. Thus, according to some embodiments, the driving controller <NUM> may include an input port receiving the touch interrupt signal TINT from the touch driver <NUM>.

The host <NUM> may receive the touch interrupt signal TINT and the touch coordinate signal TC from the touch driver <NUM>. The host <NUM> may change the input image data IMG to change a display image of the display panel <NUM> in response to the touch interrupt signal TINT and the touch coordinate signal TC.

The display panel <NUM> includes the plurality of the pixels. Each pixel includes an organic light emitting element OLED.

The pixel receives a data write gate signal GWP and GWN, a data initialization gate signal GI, an organic light emitting element initialization signal GB, the data voltage VDATA and the emission signal EM and the organic light emitting element OLED of the pixel emits light corresponding to the level of the data voltage VDATA to display the image.

According to some embodiments, the pixel may include a switching element of a first type and a switching element of a second type different from the first type. For example, the switching element of the first type may be a polysilicon thin film transistor. For example, the switching element of the first type may be a low temperature polysilicon (LTPS) thin film transistor. For example, the switching element of the second type may be an oxide thin film transistor. For example, the switching element of the first type may be a P-type transistor and the switching element of the second type may be an N-type transistor.

For example, the data write gate signal may include a first data write gate signal GWP and a second data write gate signal GWN. The first data write gate signal GWP may be applied to the P-type transistor so that the first data write gate signal GWP has an activation signal of a low level corresponding to a data writing timing. The second data write gate signal GWN may be applied to the N-type transistor so that the second data write gate signal GWN has an activation signal of a high level corresponding to the data writing timing.

At least one of the pixels may include first to seventh pixel switching elements T1 to T7, a storage capacitor CST and the organic light emitting element OLED.

The first pixel switching element T1 includes a control electrode connected to a first node N1, an input electrode connected to a second node N2 and an output electrode connected to a third node N3. For example, the first pixel switching element T1 may be the polysilicon thin film transistor. For example, the first pixel switching element T1 may be the P-type thin film transistor.

The second pixel switching element T2 includes a control electrode to which the first data write gate signal GWP is applied, an input electrode to which the data voltage VDATA is applied and an output electrode connected to the second node N2. For example, the second pixel switching element T2 may be the polysilicon thin film transistor. For example, the second pixel switching element T2 may be the P-type thin film transistor.

The third pixel switching element T3 includes a control electrode to which the second data write gate signal GWN is applied, an input electrode connected to the first node N1 and an output electrode connected to the third node N3. For example, the third pixel switching element T3 may be the oxide thin film transistor. For example, the third pixel switching element T3 may be the N-type thin film transistor.

The fourth pixel switching element T4 includes a control electrode to which the data initialization gate signal GI is applied, an input electrode to which an initialization voltage VI is applied and an output electrode connected to the first node N1. For example, the fourth pixel switching element T4 may be the oxide thin film transistor. For example, the fourth pixel switching element T4 may be the N-type thin film transistor.

The fifth pixel switching element T5 includes a control electrode to which the emission signal EM is applied, an input electrode to which a high power voltage ELVDD is applied and an output electrode connected to the second node N2. For example, the fifth pixel switching element T5 may be the polysilicon thin film transistor. For example, the fifth pixel switching element T5 may be the P-type thin film transistor.

The sixth pixel switching element T6 includes a control electrode to which the emission signal EM is applied, an input electrode connected to the third node N3 and an output electrode connected to an anode electrode of the organic light emitting element OLED. For example, the sixth pixel switching element T6 may be the polysilicon thin film transistor. For example, the sixth pixel switching element T6 may be a P-type thin film transistor. The control electrode of the sixth pixel switching element T6 may be a gate electrode, the input electrode of the sixth pixel switching element T6 may be a source electrode and the output electrode of the sixth pixel switching element T6 may be a drain electrode.

The seventh pixel switching element T7 includes a control electrode to which the organic light emitting element initialization gate signal GB is applied, an input electrode to which the initialization voltage VI is applied and an output electrode connected to the anode electrode of the organic light emitting element OLED. For example, the seventh pixel switching element T7 may be the oxide thin film transistor. For example, the seventh pixel switching element T7 may be the N-type thin film transistor. Alternatively, the seventh pixel switching element T7 may be the polysilicon thin film transistor. For example, the seventh pixel switching element T7 may be a P-type thin film transistor. When the seventh pixel switching element T7 is the P-type thin film transistor, the organic light emitting element initialization gate signal GB may have an activation signal of a low level unlike <FIG> and <FIG>.

The storage capacitor CST includes a first electrode to which the high power voltage ELVDD is applied and a second electrode connected to the first node N1.

The organic light emitting element OLED includes the anode electrode and a cathode electrode to which a low power voltage ELVSS is applied.

In <FIG>, during a first duration DU1, the first node N1 and the storage capacitor CST are initialized in response to the data initialization gate signal GI. During a second duration DU2, a threshold voltage |VTH| of the first pixel switching element T1 is compensated and the data voltage VDATA of which the threshold voltage |VTH| is compensated is written to the first node N1 in response to the first and second data write gate signals GWP and GWN. During a third duration DU3, the anode electrode of the organic light emitting element OLED is initialized in response to the organic light emitting element initialization gate signal GB. During a fourth duration DU4, the organic light emitting element OLED emit the light in response to the emission signal EM so that the display panel <NUM> displays the image.

During the first duration DU1, the data initialization gate signal GI may have an active level. For example, the active level of the data initialization gate signal GI may be a high level. When the data initialization gate signal GI has the active level, the fourth pixel switching element T4 is turned on so that the initialization voltage VI may be applied to the first node N1. The data initialization gate signal GI[N] of a present stage may be generated based on a scan signal SCAN[N-<NUM>] of a previous stage.

During the second duration DU2, the first data write gate signal GWP and the second data write gate signal GWN may have an active level. For example, the active level of the first data write gate signal GWP may be a low level and the active level of the second data write gate signal GWN may be a high level. When the first data write gate signal GWP and the second data writhe gate signal GWN have the active level, the second pixel switching element T2 and the third pixel switching element T3 are turned on. In addition, the first pixel switching element T1 is turned on in response to the initialization voltage VI. The first data write gate signal GWP[N] of the present stage may be generated based on a scan signal SCAN[N] of the present stage. The second data write gate signal GWN[N] of the present stage may be generated based on the scan signal SCAN[N] of the present stage.

A voltage which is subtraction an absolute value |VTH| of the threshold voltage of the first pixel switching element T1 from the data voltage VDATA may be charged at the first node N1 along a path generated by the first to third pixel switching elements T1, T2 and T3.

During the third duration DU3, the organic light emitting element initialization signal GB may have an active level. For example, the active level of the organic light emitting element initialization signal GB may be a high level. When the organic light emitting element initialization signal GB has the active level, the seventh pixel switching element T7 is turned on so that the initialization voltage VI may be applied to the anode electrode of the organic light emitting element OLED. The organic light emitting element initialization signal GB[N] of the present stage may be generated based on a scan signal SCAN[N+<NUM>] of a next stage.

During the fourth duration DU4, the emission signal EM may have an active level. The active level of the emission signal EM may be a low level. When the emission signal EM has the active level, the fifth pixel switching element T5 and the sixth pixel switching element T6 are turned on. In addition, the first pixel switching element T1 is turned on by the data voltage VDATA.

A driving current flows through the fifth pixel switching element T5, the first pixel switching element T1 and the sixth pixel switching element T6 to drive the organic light emitting element OLED. An intensity of the driving current may be determined by the level of the data voltage VDATA. A luminance of the organic light emitting element OLED is determined by the intensity of the driving current. The driving current ISD flowing through a path from the input electrode to the output electrode of the first pixel switching element T1 is determined as following Equation <NUM>.

In Equation <NUM>, µ is a mobility of the first pixel switching element T1. Cox is a capacitance per unit area of the first pixel switching element T1. W/L is a width to length ratio of the first pixel switching element T1. VSG is a voltage between the input electrode N2 of the first pixel switching element T1 and the control node N1 of the first pixel switching element T1. |VTH| is the threshold voltage of the first pixel switching element T1.

The voltage VG of the first node N1 after the compensation of the threshold voltage |VTH| during the second duration DU2 may be represented as following Equation <NUM>.

When the organic light emitting element OLED emits the light during the fourth duration DU4, the driving voltage VOV and the driving current ISD may be represented as following Equations <NUM> and <NUM>. In Equation <NUM>, VS is a voltage of the second node N2. <MAT> <MAT>.

The threshold voltage |VTH| is compensated during the second duration DU2, so that the driving current ISD may be determined regardless of the threshold voltage |VTH| of the first pixel switching element T1 when the organic light emitting element OLED emits the light during the fourth duration DU4.

According to some embodiments, when the image displayed on the display panel <NUM> is a still image or the display panel is operated in Always On Mode, a driving frequency of the display panel <NUM> may be decreased to reduce a power consumption. When all of the switching elements of the pixel of the display panel <NUM> are polysilicon thin film transistor, a flicker may be generated due to a leakage current of the pixel switching element in the low frequency driving mode. Thus, some of the pixel switching elements may be designed using the oxide thin film transistors. According to some embodiments, the third pixel switching element T3, the fourth pixel switching element T4 and the seventh pixel switching element T7 may be the oxide thin film transistors. The first pixel switching element T1, the second pixel switching element T2, the fifth pixel switching element T5 and the sixth pixel switching element T6 may be the polysilicon thin film transistors.

The display panel <NUM> may be driven in a normal driving mode in which the display panel <NUM> is driven in a normal driving frequency and in a low frequency driving mode in which the display panel <NUM> is driven in a frequency less than the normal driving frequency.

The display panel <NUM> may be driven in a unit of frame. The display panel <NUM> may be refreshed in every frame in the normal driving mode. Thus, the normal driving mode includes only writing frames in which the data is written in the pixel.

The display panel <NUM> may be refreshed in the frequency of the low frequency driving mode in the low frequency driving mode. Thus, the low frequency driving mode includes the writing frames in which the data is written in the pixel and holding frames in which the written data is maintained without writing the data in the pixel.

For example, when the frequency of the normal driving mode is <NUM> and the frequency of the low frequency driving mode is <NUM>, the low frequency driving mode includes one writing frame WRITE and fifty nine holding frames HOLD in a second. Herein, a length of the writing frame WRITE may be substantially the same as a length of the holding frame HOLD. For example, when the frequency of the normal driving mode is <NUM> and the frequency of the low frequency driving mode is <NUM>, fifty nine continuous holding frames HOLD are located between two adjacent writing frames WRITE.

For example, when the frequency of the normal driving mode is <NUM> and the frequency of the low frequency driving mode is <NUM>, the low frequency driving mode includes ten writing frame WRITE and fifty holding frames HOLD in a second. Herein, a length of the writing frame WRITE may be substantially the same as a length of the holding frame HOLD. For example, when the frequency of the normal driving mode is <NUM> and the frequency of the low frequency driving mode is <NUM>, five continuous holding frames HOLD are located between two adjacent writing frames WRITE.

According to some embodiments, the second data write gate signal GWN and the data initialization gate signal GI may have a first frequency in the low frequency driving mode. The first frequency may be the frequency of the low frequency driving mode. In contrast, the first data write gate signal GWP, the emission signal EM and the organic light emitting element initialization gate signal GB may have a second frequency greater than the first frequency. The second frequency may be the normal frequency of the normal driving mode. In <FIG>, for example, the first frequency is <NUM> and the second frequency is <NUM>.

The emission signal EM in the frame may include an emission off duration OD when the emission signal EM has the inactive level and an emission on duration when the emission signal EM has the active level.

According to some embodiments, the driving controller <NUM> determines the driving frequency of the switching element of the first type to a first driving frequency (e.g. the normal driving frequency) and the driving frequency of the switching element of the second type to a second driving frequency (e.g. the low driving frequency) less than the first driving frequency in the low frequency driving mode.

The driving controller <NUM> determines the driving frequency of the switching element of the first type to the first driving frequency (e.g. the normal driving frequency) and the driving frequency of the switching element of the second type to the first driving frequency (e.g. the normal driving frequency) in the normal driving mode.

According to some embodiments of the display apparatus and the method of driving the display apparatus, the display quality in the low frequency driving mode may be enhanced.

Claim 1:
A display apparatus comprising:
a display panel configured to display an image based on input image data including input frame images;
a gate driver configured to output a gate signal to the display panel;
a data driver configured to output a data voltage to the display panel;
a driving controller;
a host configured to output the input image data to the driving controller;
the driving controller further configured to determine a normal driving mode having a driving frequency which is a normal driving frequency when the input image data received from the host represents a video image and a low frequency driving mode having a driving frequency of less than the normal driving mode when the input image data received from the host represents a still image, and to control an operation of the gate driver and an operation of the data driver in accordance with the determined normal driving mode or the determined low frequency driving mode;
a touch driver configured to detect a touch event occurring on the display panel during a frame, and to output a touch interrupt signal directly to the driving controller, wherein the touch interrupt signal represents the touch event, wherein the touch driver is configured to generate a touch coordinate signal representing a touch position, and to output the touch interrupt signal and the touch coordinate signal to the host,
wherein the driving controller is configured to perceive the touch event immediately on receipt of the touch interrupt signal, and
wherein, when the display panel is driven in the low frequency driving mode, the driving controller is further configured in response to the touch event to drive the display panel in the normal driving mode in a right next frame of the frame.