Display device

Abstract

A display device includes: a display panel including pixels; and a display panel driver driving the display panel. When a driving frequency of the display panel changes from a first driving frequency to a second driving frequency different from the first driving frequency, the display panel driver determines a non-transmission time of a first frame period of the second driving frequency based on a non-transmission time of a frame period of the first driving frequency.

Description

Technical Field

[0001] Embodiments of the present invention relate to a display device, and more particularly, to a display device for improving display quality in variable frequency driving. Background Art

[0002] Typically, a display device may include a display panel and a display panel driver. The display panel may include gate lines, data lines, emission lines, and pixels. The display panel driver may include a gate driver for providing a gate signal to the gate line, a data driver for providing a data voltage to the data line, an emission driver for providing an emission signal to the emission line, and a drive controller for controlling the gate driver, the data driver, and the emission driver. Such a display device may be driven at a variable frequency. Summary of the invention

[0003] In a display device driven with a variable frequency, when the driving frequency of the display panel is changed from a first driving frequency to a second driving frequency different from the first driving frequency, the hysteresis characteristic of the driving transistor included in the pixel may change, and a brightness difference of the display panel may occur. The brightness difference of the display panel may be visible as flicker. When the average brightness of the first frame period of the second driving frequency is equal to the average brightness of the frame period of the first driving frequency, the flicker can be improved.

[0004] However, even if the average brightness of the first frame period of the second driving frequency is equal to the average brightness of the frame period of the first driving frequency, momentary flicker may be visible and the display quality may be degraded.

[0005] Embodiments of the present invention provide a display device for improving instantaneous flicker when a driving frequency of a display panel is changed from a first driving frequency to a second driving frequency.

[0006] In an embodiment of a display device according to the present invention, the display device includes: a display panel including pixels; and a display panel driver configured to drive the display panel. In such an embodiment, when the driving frequency of the display panel is changed from a first driving frequency to a second driving frequency different from the first driving frequency, the display panel driver determines the non-emission time of the first frame period of the second driving frequency based on the non-emission time of the frame period of the first driving frequency.

[0007] In an embodiment, the emission duty cycle of the first frame period of the second driving frequency may be determined based on the non-emission time of the first frame period of the second driving frequency.

[0008] In an embodiment, the non-emission time of the first frame period of the second driving frequency may be equal to the non-emission time of the frame period of the first driving frequency.

[0009] In an embodiment, when the second driving frequency is lower than the first driving frequency, an emission duty ratio of a first frame period of the second driving frequency may be greater than an emission duty ratio of a frame period of the first driving frequency.

[0010] In an embodiment, when the second driving frequency is greater than the first driving frequency, an emission duty ratio of a first frame period of the second driving frequency may be less than an emission duty ratio of a frame period of the first driving frequency.

[0011] In an embodiment, an average brightness of a first frame period of the second driving frequency may be equal to an average brightness of a frame period of the first driving frequency.

[0012] In an embodiment, when the second driving frequency is lower than the first driving frequency, the peak brightness of the first frame period of the second driving frequency may be lower than the peak brightness of the frame period of the first driving frequency.

[0013] In an embodiment, when the second driving frequency is greater than the first driving frequency, the peak brightness of the first frame period of the second driving frequency may be greater than the peak brightness of the frame period of the first driving frequency.

[0014] In an embodiment, during multiple frame periods of the second driving frequency, the emission duty cycle of the frame period of the second driving frequency can be changed from the emission duty cycle of the first frame period of the second driving frequency to the target emission duty cycle of the frame period of the second driving frequency.

[0015] In an embodiment, during a plurality of frame periods of the second driving frequency, an emission duty ratio of a frame period of the second driving frequency may be gradually changed.

[0016] According to an embodiment of the display device, the non-emission time of the first frame period of the second driving frequency may be determined based on the non-emission time of the frame period of the first driving frequency, so that instantaneous flicker may be improved.

[0017] In such an embodiment, the average brightness of the first frame period of the second driving frequency may be equal to the average brightness of the frame period of the first driving frequency, so that the flicker may be improved.

[0018] In such an embodiment, during each frame period of the second driving frequency, the emission duty cycle of the frame period of the second driving frequency can be changed from the emission duty cycle of the first frame period of the second driving frequency to the target emission duty cycle of the frame period of the second driving frequency, so that motion blur can be improved.

[0019] In such an embodiment, the emission duty cycle of the frame period of the second driving frequency can be gradually changed during each frame period of the second driving frequency, and the average brightness of the frame period of the second driving frequency can be constant during each frame period of the second driving frequency, so that the brightness variation of the display panel can be minimized. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and other features of the embodiments of the present invention will become more apparent by describing in detail the embodiments of the present invention with reference to the accompanying drawings, in which:

[0021] Figure 1 is a block diagram for describing a display device according to an embodiment of the present invention;

[0022] Figure 2 Is used to describe Figure 1 A conceptual diagram of the driving frequency of the display panel;

[0023] Figure 3 It is shown that the Figure 1 A circuit diagram of an embodiment of a pixel in a display device;

[0024] Figure 4 is a view for describing the brightness of a display panel according to a transmission signal;

[0025] Figure 5 is a timing diagram for describing a frame period at a driving frequency of 120 Hz;

[0026] Figure 6 is a timing diagram for describing a frame period at a driving frequency of 60 Hz;

[0027] Figure 7 is a timing diagram for describing a state in which flicker is visually recognized when the driving frequency of the display panel is changed from a first driving frequency to a second driving frequency;

[0028] Figure 8 is a timing diagram for describing a state in which instantaneous flicker is visually recognized when the driving frequency of the display panel is changed from a first driving frequency to a second driving frequency;

[0029] Fig. 9 and Fig.10 is a timing diagram for describing a non-emission time adjustment operation for improving instantaneous flicker according to an embodiment;

[0030] Fig.11 is a block diagram for describing an electronic device; and

[0031] Fig.12 is used to describe Fig.11 FIG. 1 is a diagram of an embodiment in which the electronic device is implemented as a smart phone. DETAILED DESCRIPTION

[0032] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which various embodiments are shown. However, the present invention may be embodied in a variety of different forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that this disclosure will be comprehensive and complete and will fully convey the scope of the invention to those skilled in the art. The same reference numerals refer to the same elements throughout.

[0033] It will be understood that when an element is referred to as being “on” another element, it can be directly on the other element or intervening elements may be present therebetween. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present.

[0034] It will be understood that although the terms "first", "second", "third", etc. may be used herein to describe various elements, components, regions, layers and / or portions, these elements, components, regions, layers and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or portion from another element, component, region, layer or portion. Therefore, the first element, component, region, layer or portion discussed below may be referred to as a second element, component, region, layer or portion without departing from the teachings herein.

[0035] The terms used herein are only for the purpose of describing specific embodiments, and are not intended to be limited. As used herein, "one", "the (described)" and "at least one" do not represent quantitative restrictions, and are intended to include both singular and plural numbers, unless the context clearly indicates otherwise. Therefore, in the claim, mentioning "one" element and then mentioning "described" element includes one element and multiple elements. For example, "element" has the same meaning as "at least one element", unless the context clearly indicates otherwise. "At least one" is not interpreted as being limited to "one". "Or" means "and / or". As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It will be further understood that the term "include" and / or its variants or "include" and / or its variants are used in this specification to indicate the presence of stated features, regions, wholes, steps, operations, elements and / or parts, but does not exclude the presence or addition of one or more other features, regions, wholes, steps, operations, elements, parts and / or their groups.

[0036] In addition, relative terms such as "lower" or "bottom" and "upper" or "top" may be used herein to describe the relationship of one element to another element as shown in the accompanying drawings. It will be understood that relative terms are intended to cover different orientations of the device in addition to the orientation depicted in the accompanying drawings. For example, if the device in one of the figures in the accompanying drawings is turned over, the element described as being on the "lower" side of the other elements will then be oriented to be on the "upper" side of the other elements. Therefore, depending on the specific orientation of the drawings, the term "lower" can cover both "lower" and "upper" orientations. Similarly, if the device in one of the figures in the accompanying drawings is turned over, the element described as being "below" or "below" the other elements will then be oriented to be "above" the other elements. Therefore, the term "below" or "below" can cover both upper and lower orientations.

[0037] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless explicitly so defined herein.

[0038] Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

[0039] Figure 1 is a block diagram for describing a display device 10 according to an embodiment of the present invention.

[0040] refer to Figure 1 , an embodiment of the display device 10 may include a display panel 100 and a display panel driver. The display panel driver may include a driving controller 200, a gate driver 300, a gamma reference voltage generator 400, a data driver 500, and an emission driver 600.

[0041] In an embodiment, for example, the driving controller 200 and the data driver 500 may be integrally formed with each other as a single module or chip. In an embodiment, for example, the driving controller 200, the gamma reference voltage generator 400, and the data driver 500 may be integrally formed with each other as a single module or chip. In an embodiment, for example, the driving controller 200, the gate driver 300, the gamma reference voltage generator 400, and the data driver 500 may be integrally formed with each other as a single module or chip. In an embodiment, for example, the driving controller 200, the gate driver 300, the gamma reference voltage generator 400, the data driver 500, and the emission driver 600 may be integrally formed with each other as a single module or chip. In an embodiment, a driving module in which at least the driving controller 200 and the data driver 500 are integrally formed may be referred to as a timing controller embedded data driver (TED).

[0042] The display panel 100 may include a display area for displaying an image and a peripheral area disposed adjacent to the display area.

[0043] In an embodiment, for example, the display panel 100 may be an organic light emitting diode display panel including an organic light emitting diode. In another embodiment, for example, the display panel 100 may be a quantum dot organic light emitting diode display panel including an organic light emitting diode and a quantum dot color filter. In another embodiment, for example, the display panel 100 may be a quantum dot nano light emitting diode display panel including a nano light emitting diode and a quantum dot color filter. In another embodiment, for example, the display panel 100 may be a liquid crystal display panel including a liquid crystal layer.

[0044] The display panel 100 may include gate lines GL, data lines DL, emission lines EML, and pixels P electrically connected to the gate lines GL, data lines DL, and emission lines EML. The gate lines GL may extend in a first direction, the data lines DL may extend in a second direction crossing the first direction, and the emission lines EML may extend in the first direction.

[0045] The driving controller 200 may receive input image data IMG and an input control signal CONT from an external device (not shown). In an embodiment, for example, 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 main clock signal and a data enable signal. The input control signal CONT may further include a vertical synchronization signal and a horizontal synchronization signal.

[0046] The driving controller 200 may generate 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 input image data IMG and an input control signal CONT.

[0047] The driving controller 200 may generate a first control signal CONT1 for controlling the operation of the gate driver 300 based on the input control signal CONT, and output the first control signal CONT1 to the gate driver 300. The first control signal CONT1 may include a vertical start signal and a gate clock signal.

[0048] The driving controller 200 may generate a second control signal CONT2 for controlling the operation of the data driver 500 based on the input control signal CONT, and output the second control signal CONT2 to the data driver 500. The second control signal CONT2 may include a horizontal start signal and a load signal.

[0049] The driving controller 200 may generate a data signal DATA based on the input image data IMG. The driving controller 200 may output the data signal DATA to the data driver 500.

[0050] The driving controller 200 may generate a third control signal CONT3 for controlling the operation of the gamma reference voltage generator 400 based on the input control signal CONT, and output the third control signal CONT3 to the gamma reference voltage generator 400 .

[0051] The driving controller 200 may generate a fourth control signal CONT4 for controlling the operation of the emission driver 600 based on the input control signal CONT, and output the fourth control signal CONT4 to the emission driver 600 .

[0052] The gate driver 300 may generate a gate signal for driving the gate line GL in response to the first control signal CONT1 received from the driving controller 200. The gate driver 300 may output the gate signal to the gate line GL.

[0053] In an embodiment, the gate driver 300 may be integrated in a peripheral area of ​​the display panel 100 .

[0054] The gamma reference voltage generator 400 may generate a gamma reference voltage VGREF in response to the third control signal CONT3 received from the driving controller 200. The gamma reference voltage generator 400 may provide the gamma reference voltage VGREF to the data driver 500. The gamma reference voltage VGREF may have a value corresponding to each data signal DATA.

[0055] In an embodiment, the gamma reference voltage generator 400 may be provided in the driving controller 200 , or may be provided in the data driver 500 .

[0056] The data driver 500 may receive the second control signal CONT2 and the data signal DATA from the driving controller 200, and receive the gamma reference voltage VGREF from the gamma reference voltage generator 400. The data driver 500 may convert the data signal DATA into a data voltage of an analog type using the gamma reference voltage VGREF. The data driver 500 may output the data voltage to the data line DL.

[0057] The emission driver 600 may generate an emission signal for driving the emission lines EML in response to the fourth control signal CONT4 received from the driving controller 200. The emission driver 600 may output the emission signal to the emission lines EML.

[0058] In an embodiment, the emission driver 600 may be integrated in a peripheral area of ​​the display panel 100. In an embodiment, the emission driver 600 may be mounted on a peripheral area of ​​the display panel 100.

[0059] In an embodiment, Figure 1 As shown in , the gate driver 300 may be disposed on a first side of the display panel 100, and the emission driver 600 may be disposed on a second side of the display panel 100. However, the present invention is not limited thereto. In an embodiment, for example, both the gate driver 300 and the emission driver 600 may be disposed on a first side of the display panel 100. In an embodiment, for example, both the gate driver 300 and the emission driver 600 may be disposed on both sides of the display panel 100. In an embodiment, for example, the gate driver 300 and the emission driver 600 may be formed integrally with each other as a single module or chip.

[0060] Figure 2 Is used to describe Figure 1 A conceptual diagram of a driving frequency of the display panel 100.

[0061] refer to Figure 2 , the display panel 100 may be driven at a variable frequency. The first frame period FP1 having the first driving frequency DF1 may include a first effective period AC1 and a first blank period BL1. The second frame period FP2 having the second driving frequency DF2 different from the first driving frequency DF1 may include a second effective period AC2 and a second blank period BL2. The third frame period FP3 having the third driving frequency DF3 different from the first driving frequency DF1 and the second driving frequency DF2 may include a third effective period AC3 and a third blank period BL3.

[0062] In an embodiment, for example, Figure 2 As shown in FIG. 1 , the first frame period FP1 may have a driving frequency of 120 Hertz (Hz), the second frame period FP2 may have a driving frequency of 90 Hz, and the third frame period FP3 may have a driving frequency of 60 Hz.

[0063] The first active period AC1 may have the same length as the second active period AC2, and the first blank period BL1 may have a length different from that of the second blank period BL2. In other words, the frame period of the second driving frequency DF2 may be different from that of the first driving frequency DF1.

[0064] The second active period AC2 may have the same length as the third active period AC3, and the second blank period BL2 may have a length different from that of the third blank period BL3. In other words, the frame period of the third driving frequency DF3 may be different from that of the second driving frequency DF2.

[0065] Figure 3 It is shown that the Figure 1 A circuit diagram of an embodiment of a pixel P in a display device 10 is shown in FIG.

[0066] refer to Figure 3 , an embodiment of the pixel P may include a first transistor T1 to a seventh transistor T7 and a light emitting element EE.

[0067] The first transistor (ie, driving transistor) T1 may include a gate electrode connected to the first node N1, a first electrode connected to the second node N2, and a second electrode connected to the third node N3.

[0068] The second transistor T2 may include a gate electrode to which the data write gate signal GW is applied, a first electrode to which the data voltage VDATA is applied, and a second electrode connected to the second node N2. The data voltage VDATA may be applied to the pixel P based on the data write gate signal GW.

[0069] The third transistor T3 may include a gate electrode to which the compensation gate signal GC is applied, a first electrode connected to the third node N3, and a second electrode connected to the first node N1. A threshold voltage of the first transistor T1 may be compensated based on the compensation gate signal GC.

[0070] The fourth transistor T4 may include a gate electrode applied with the data initialization gate signal GI, a first electrode applied with the data initialization voltage VINIT, and a second electrode connected to the first node N1. The gate electrode of the first transistor T1 may be initialized to the data initialization voltage VINIT based on the data initialization gate signal GI.

[0071] The fifth transistor T5 may include a gate electrode to which the emission signal EM is applied, a first electrode to which the first driving voltage ELVDD is applied, and a second electrode connected to the second node N2.

[0072] The sixth transistor T6 may include a gate electrode to which the emission signal EM is applied, a first electrode connected to the third node N3, and a second electrode connected to the anode electrode of the light emitting element EE.

[0073] The seventh transistor T7 may include a gate electrode applied with the anode initialization gate signal GB, a first electrode applied with the anode initialization voltage VAINIT, and a second electrode connected to the anode electrode of the light emitting element EE. The anode electrode of the light emitting element EE may be initialized to the anode initialization voltage VAINIT based on the anode initialization gate signal GB.

[0074] The light emitting element EE may include an anode electrode and a cathode electrode to which a second driving voltage ELVSS is applied. The second driving voltage ELVSS may be lower than the first driving voltage ELVDD.

[0075] The pixel P may further include a storage capacitor CST including a first electrode to which the first driving voltage ELVDD is applied and a second electrode connected to the first node N1. The storage capacitor CST may store a voltage corresponding to the data voltage VDATA.

[0076] The first transistor T1 may generate a driving current ID. The driving current ID may flow in the order of the fifth transistor T5, the first transistor T1, the sixth transistor T6, and the light emitting element EE. The light emitting element EE may emit light based on the driving current ID. The brightness of the light emitting element EE may be determined by the intensity of the driving current ID, and the intensity of the driving current ID may be determined by the level of the data voltage VDATA.

[0077] In the case where all transistors included in the pixel P are P-type transistors, flickering may be caused due to leakage current of the transistors during low-frequency driving. Therefore, in an embodiment, some of the transistors included in the pixel P may be N-type transistors. In an embodiment, for example, the third transistor T3 and the fourth transistor T4 may be N-type transistors, and the first transistor T1, the second transistor T2, the fifth transistor T5, the sixth transistor T6, and the seventh transistor T7 may be P-type transistors.

[0078] Although for ease of description, Figure 3 2 shows an embodiment in which the pixel P includes first to seventh transistors T1 to T7 and a light emitting element EE, but the present disclosure is not limited thereto.

[0079] Figure 4is a view for describing the luminance LUM of the display panel 100 according to the emission signal EM. Figure 5 is a timing chart for describing a frame period FP at a driving frequency of 120 Hz. Figure 6 is a timing chart for describing a frame period FP at a driving frequency of 60 Hz.

[0080] refer to Figures 1 to 6 In an embodiment, the frame period FP may include an emission period EP and a non-emission period NEP. The emission period EP may be a period in which the light emitting element EE emits light based on the driving current ID, and the non-emission period NEP may be a period in which the light emitting element EE does not emit light.

[0081] The emission period EP and the non-emission period NEP may be distinguished from each other based on the emission signal EM. In an embodiment, for example, when the emission signal EM has a low level, the drive current ID may flow to the light emitting element EE, the light emitting element EE may emit light, and the brightness LUM of the display panel 100 may be the peak brightness LUM_PEAK. In an embodiment, for example, when the emission signal EM has a high level, the drive current ID may not flow to the light emitting element EE, the light emitting element EE may not emit light, and the brightness LUM of the display panel 100 may be 0.

[0082] The average brightness LUM_AVG of the display panel 100 may be an average value of the brightness LUM of the display panel 100 in the frame period FP. The average brightness LUM_AVG of the display panel 100 may be determined based on the grayscale of the input image data IMG. For example, when the grayscale of the input image data IMG is not 0, the average brightness LUM_AVG of the display panel 100 may not be 0, and the peak brightness LUM_PEAK of the display panel 100 may be greater than the average brightness LUM_AVG of the display panel 100. For example, when the grayscale of the input image data IMG is zero (0), each of the average brightness LUM_AVG of the display panel 100 and the peak brightness LUM_PEAK of the display panel 100 may be zero (0). In addition, when the grayscale of the input image data IMG is constant, the average brightness LUM_AVG of the display panel 100 may be constant regardless of the driving frequency DF of the display panel 100.

[0083] The display panel 100 may be driven at various driving frequencies DF.

[0084] In an embodiment, for example, Figure 5As shown in , the driving frequency DF of the display panel 100 may be 120 Hz. When the display panel 100 has the driving frequency DF of 120 Hz, the length of the frame period FP may be 8.33 milliseconds (ms), each of the emission duty cycle ER and the non-emission duty cycle NER may be 50%, and each of the emission time ET corresponding to the emission duty cycle ER and the non-emission time NET corresponding to the non-emission duty cycle NER may be 4.165 ms.

[0085] In an embodiment, for example, Figure 6 As shown in , the driving frequency DF of the display panel 100 may be 60 Hz. When the display panel 100 has the driving frequency DF of 60 Hz, the length of the frame period FP may be 16.66 ms, each of the emission duty cycle ER and the non-emission duty cycle NER may be 50%, and each of the emission time ET corresponding to the emission duty cycle ER and the non-emission time NET corresponding to the non-emission duty cycle NER may be 8.33 ms.

[0086] The emission duty cycle ER may be constant in the frame period FP. When the emission duty cycle ER is constant in the frame period FP, motion blur may be improved. Therefore, when the grayscale of the input image data IMG is the same or constant, the peak brightness LUM_PEAK and the average brightness LUM_AVG of the driving frequency DF of 120 Hz may be equal to the peak brightness LUM_PEAK and the average brightness LUM_AVG of the driving frequency DF of 60 Hz, respectively.

[0087] Figure 7 is a timing diagram for describing a state in which flicker is visually recognized when the driving frequency DF of the display panel 100 is changed from the first driving frequency DF1 to the second driving frequency DF2.

[0088] refer to Figures 1 to 7 In an embodiment, the display panel 100 may be driven at a variable frequency. The driving frequency DF of the display panel 100 may be changed from the first driving frequency DF1 to a second driving frequency DF2 different from the first driving frequency DF1. For example, the first driving frequency DF1 may be 120 Hz, and the second driving frequency DF2 may be 60 Hz. Although for ease of description, in Figure 7 , the first driving frequency DF1 is greater than the second driving frequency DF2, but the present disclosure is not limited thereto. According to an embodiment, the first driving frequency DF1 may be less than the second driving frequency DF2.

[0089] When the driving frequency of the display panel 100 is changed from the first driving frequency DF1 to the second driving frequency DF2, the hysteresis characteristic of the driving transistor T1 may be changed. The hysteresis characteristic of the driving transistor T1 may mean that the driving current ID corresponds to the gate-source voltage of the driving transistor T1. Therefore, when the hysteresis characteristic of the driving transistor T1 changes, the brightness of the display panel 100 corresponding to the same data voltage VDATA may change. For example, the peak brightness LUM_PEAK' of the first frame period FP1 of the second driving frequency DF2 may be greater than the peak brightness LUM_PEAK of the frame period FP of the first driving frequency DF1, and the average brightness LUM_AVG' of the first frame period FP1 of the second driving frequency DF2 may be greater than the average brightness LUM_AVG of the frame period FP of the first driving frequency DF1. The difference between the average brightness LUM_AVG' of the first frame period FP1 of the second driving frequency DF2 and the average brightness LUM_AVG of the frame period FP of the first driving frequency DF1 may be visually recognized as flickering.

[0090] Figure 8 is a timing chart for describing a state in which a momentary flicker is visually recognized when the driving frequency of the display panel 100 is changed from the first driving frequency DF1 to the second driving frequency DF2. Fig. 9 and Fig.10 is a timing diagram for describing a non-emission time adjustment operation for improving instantaneous flicker according to an embodiment.

[0091] refer to Figures 1 to 10 , when the driving frequency of the display panel 100 is changed from the first driving frequency DF1 to the second driving frequency DF2, flicker may be visually recognized. For example, the first driving frequency DF1 may be 120 Hz, and the second driving frequency DF2 may be 60 Hz. In an embodiment, even in the presence of a difference in the hysteresis characteristic of the driving transistor T1, flicker may be improved by changing the average brightness LUM_AVG' of the first frame period FP1 of the second driving frequency DF2 to the average brightness LUM_AVG of the frame period FP of the first driving frequency DF1.

[0092] In such an embodiment, although the average brightness LUM_AVG′ of the first frame period FP1 of the second driving frequency DF2 is equal to the average brightness LUM_AVG of the frame period FP of the first driving frequency DF1 , momentary flicker may be visually recognized.

[0093] In an embodiment, when the driving frequency of the display panel 100 is changed from the first driving frequency DF1 to the second driving frequency DF2, the non-emission time NET of the first frame period FP1 of the second driving frequency DF2 may be adjusted to prevent instantaneous flicker from being visually recognized. In such an embodiment, the non-emission time NET of the first frame period FP1 of the second driving frequency DF2 may be determined based on the non-emission time NET of the frame period FP of the first driving frequency DF1.

[0094] According to an embodiment, the non-emission time NET of the first frame period FP1 of the second driving frequency DF2 may be equal to the non-emission time NET of the frame period FP of the first driving frequency DF1. However, the present disclosure is not limited thereto. The non-emission time NET of the first frame period FP1 of the second driving frequency DF2 may be determined to minimize the difference between the non-emission time NET of the first frame period FP1 of the second driving frequency DF2 and the non-emission time NET of the frame period FP of the first driving frequency DF1.

[0095] In an embodiment, for example, the non-emission time NET of the frame period FP of the first driving frequency DF1 may be 4.165 ms. In this case, the non-emission time NET of the first frame period FP1 of the second driving frequency DF2 may be determined to be 4.165 ms.

[0096] According to an embodiment, the emission duty ratio ER of the first frame period FP1 of the second driving frequency DF2 may be determined based on the determined non-emission time NET of the first frame period FP1 of the second driving frequency DF2. When the non-emission time NET of the first frame period FP1 of the second driving frequency DF2 is 4.165ms, the emission duty ratio ER of the first frame period FP1 of the second driving frequency DF2 may be determined to be 75%, and the non-emission duty ratio NER of the first frame period FP1 of the second driving frequency DF2 may be determined to be 25%.

[0097] When the second driving frequency DF2 is lower than the first driving frequency DF1, the emission duty ratio ER of the first frame period FP1 of the second driving frequency DF2 may be greater than the emission duty ratio ER of the frame period FP of the first driving frequency DF1. When the second driving frequency DF2 is higher than the first driving frequency DF1, the emission duty ratio ER of the first frame period FP1 of the second driving frequency DF2 may be less than the emission duty ratio ER of the frame period FP of the first driving frequency DF1.

[0098] In an embodiment, as described above, when the non-emission time NET of the first frame period FP1 of the second driving frequency DF2 is determined based on the non-emission time NET of the frame period FP of the first driving frequency DF1 , instantaneous flicker may be improved.

[0099] In an embodiment, the average brightness LUM_AVG' of the first frame period FP1 of the second driving frequency DF2 may be equal to the average brightness LUM_AVG of the frame period FP of the first driving frequency DF1 to prevent flickering from being visually recognized. When the second driving frequency DF2 is less than the first driving frequency DF1, the peak brightness LUM_PEAK' of the first frame period FP1 of the second driving frequency DF2 may be less than the peak brightness LUM_PEAK of the frame period FP of the first driving frequency DF1. When the second driving frequency DF2 is greater than the first driving frequency DF1, the peak brightness LUM_PEAK' of the first frame period FP1 of the second driving frequency DF2 may be greater than the peak brightness LUM_PEAK of the frame period FP of the first driving frequency DF1.

[0100] In an embodiment, the emission duty ratio ER of the frame period FP of the second driving frequency DF2 may be changed from the emission duty ratio ER of the first frame period FP1 of the second driving frequency DF2 to the target emission duty ratio of the frame period FP of the second driving frequency DF2 to prevent the motion blur from being visually recognized. The target emission duty ratio of the frame period FP of the second driving frequency DF2 may be equal to the emission duty ratio ER of the frame period FP of the first driving frequency DF1. In an embodiment, for example, Fig. 9 As shown in , the emission duty cycle ER of the frame period FP of the second driving frequency DF2 may have an emission duty cycle ER of 75% in the first frame period FP1 of the second driving frequency DF2, and may be changed to an emission duty cycle ER of 50% in the second frame period FP2 of the second driving frequency DF2.

[0101] In an embodiment, the emission duty ratio ER of the frame period FP of the second driving frequency DF2 may be gradually changed to prevent a change in the brightness of the display panel 100 from being visually recognized during the process of changing the emission duty ratio ER of the frame period FP of the second driving frequency DF2 from the emission duty ratio ER to the target emission duty ratio of the frame period FP of the second driving frequency DF2. In an embodiment, for example, Fig.10 As shown in, the emission duty cycle ER of the frame period FP of the second driving frequency DF2 can have an emission duty cycle ER of 75% in the first frame period FP1 of the second driving frequency DF2, can be changed to an emission duty cycle ER of 60% in the second frame period FP2 of the second driving frequency DF2, and can be changed to an emission duty cycle ER of 50% in the third frame period FP3 of the second driving frequency DF2.

[0102] When the second driving frequency DF2 is lower than the first driving frequency DF1, the emission duty cycle ER of the frame period FP of the second driving frequency DF2 may be gradually reduced. When the second driving frequency DF2 is higher than the first driving frequency DF1, the emission duty cycle ER of the frame period FP of the second driving frequency DF2 may be gradually increased.

[0103] When the emission duty cycle ER of the frame period FP of the second driving frequency DF2 is gradually changed, the average brightness LUM_AVG of the frame period FP of the second driving frequency DF2 can be constant. In an embodiment, for example, each of the average brightness LUM_AVG' of the first frame period FP1 of the second driving frequency DF2 and the average brightness LUM_AVG' of the second frame period FP2 of the second driving frequency DF2 can be equal to the average brightness LUM_AVG of the frame period FP of the first driving frequency DF1.

[0104] In an embodiment, as described above, the non-emission time NET of the first frame period FP1 of the second driving frequency DF2 can be determined based on the non-emission time NET of the frame period FP of the first driving frequency DF1, so that instantaneous flicker can be improved. In an embodiment, the average brightness LUM_AVG' of the first frame period FP1 of the second driving frequency DF2 can be equal to the average brightness LUM_AVG of the frame period FP of the first driving frequency DF1, so that flicker can be improved. In an embodiment, the emission duty ratio ER of the frame period FP of the second driving frequency DF2 can be changed from the emission duty ratio ER of the first frame period FP1 of the second driving frequency DF2 to the target emission duty ratio of the frame period FP of the second driving frequency DF2 during each frame period of the second driving frequency DF2, so that motion blur can be improved. In an embodiment, during each frame period of the second driving frequency DF2, the emission duty ratio ER of each frame period FP of the second driving frequency DF2 can be gradually changed, and during each frame period of the second driving frequency DF2, the average brightness LUM_AVG of the frame period FP of the second driving frequency DF2 can be constant, so that the change in brightness of the display panel 100 can be minimized.

[0105] Fig.11 is a block diagram for describing the electronic device 1000 . Fig.12 is used to describe Fig.11 The electronic device 1000 is implemented as a diagram of an embodiment of a smart phone.

[0106] refer to Fig.11 and Fig.12 , an embodiment of the electronic device 1000 may include a processor 1010, a memory device 1020, a storage device 1030, an input / output (I / O) device 1040, a power supply 1050, and a display device 1060. The display device 1060 may be Figure 1The display device 10. In addition, the electronic device 1000 may further include a plurality of ports for communicating with a video card, a sound card, a memory card, a universal serial bus (USB) device, or other electronic devices.

[0107] In an embodiment, Fig.12 As shown in , the electronic device 1000 may be implemented as a smart phone. However, the electronic device 1000 is not limited thereto. For example, the electronic device 1000 may be implemented as a cellular phone, a video phone, a smart tablet, a smart watch, a tablet computer, a car navigation system, a computer monitor, a laptop computer, or a head mounted display (HMD) device, etc.

[0108] The processor 1010 may perform various computing functions. The processor 1010 may be a microprocessor, a central processing unit (CPU), an application processor (AP), etc. The processor 1010 may be coupled to other components via an address bus, a control bus, or a data bus, etc. In addition, the processor 1010 may be coupled to an expansion bus such as a peripheral component interconnect (PCI) bus.

[0109] The memory device 1020 may store data for operation of the electronic device 1000. For example, the memory device 1020 may include at least one nonvolatile memory device such as an erasable programmable read-only memory (EPROM) device, an electrically erasable programmable read-only memory (EEPROM) device, a flash memory device, a phase change random access memory (PRAM) device, a resistive random access memory (RRAM) device, a nano floating gate memory (NFGM) device, a polymer random access memory (PoRAM) device, a magnetic random access memory (MRAM) device, or a ferroelectric random access memory (FRAM) device, and / or at least one volatile memory device such as a dynamic random access memory (DRAM) device, a static random access memory (SRAM) device, or a mobile DRAM device.

[0110] The storage device 1030 may include a solid state drive (SSD) device, a hard disk drive (HDD) device, or a CD-ROM device, etc.

[0111] I / O devices 1040 may include input devices such as a keyboard, keys, a mouse device, a touch pad or a touch screen, and output devices such as a printer or a speaker. In some embodiments, I / O devices 1040 may include a display device 1060 .

[0112] The power supply 1050 may provide power for the operation of the electronic device 1000 .

[0113] Display device 1060 may be connected to other components via a bus or other communication link.

[0114] Embodiments of the present invention can be applied to any display device and any electronic device including a display device, such as a mobile phone, a smart phone, a digital television (TV), a three-dimensional (3D) television, a personal computer (PC) (e.g., a tablet computer or a laptop computer), home appliances, a personal digital assistant (PDA), a portable multimedia player (PMP), a digital camera, a music player, a portable game console, a navigation device, etc.

[0115] The present invention should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be comprehensive and complete, and will fully convey the concept of the present invention to those skilled in the art.

[0116] While the invention has been particularly shown and described with reference to embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit or scope of the invention as defined by the claims.

Claims

1. A display device, comprising: A display panel, including pixels; as well as A display panel driver drives the display panel. When the driving frequency of the display panel changes from a first driving frequency to a second driving frequency different from the first driving frequency, the display panel driver determines the non-emission time of the first frame period of the second driving frequency based on the non-emission time of the frame period of the first driving frequency.

2. The display device according to claim 1, wherein: An emission duty ratio of the first frame period of the second driving frequency is determined based on the non-emission time of the first frame period of the second driving frequency.

3. The display device according to claim 1, wherein: The non-emission time of the first frame period of the second driving frequency is equal to the non-emission time of the frame period of the first driving frequency.

4. The display device according to claim 3, wherein: When the second driving frequency is lower than the first driving frequency, an emission duty ratio of the second driving frequency in the first frame period is greater than an emission duty ratio of the first driving frequency in the frame period.

5. The display device according to claim 3, wherein: When the second driving frequency is greater than the first driving frequency, an emission duty ratio of the second driving frequency in the first frame period is smaller than an emission duty ratio of the first driving frequency in the frame period.

6. The display device according to claim 1, wherein: An average brightness of the first frame period of the second driving frequency is equal to an average brightness of the frame period of the first driving frequency.

7. The display device according to claim 6, wherein: When the second driving frequency is lower than the first driving frequency, the peak brightness of the first frame period of the second driving frequency is lower than the peak brightness of the frame period of the first driving frequency.

8. The display device according to claim 6, wherein: When the second driving frequency is greater than the first driving frequency, the peak brightness of the first frame period of the second driving frequency is greater than the peak brightness of the first frame period of the first driving frequency.

9. The display device according to claim 1, wherein: During a plurality of frame periods of the second driving frequency, an emission duty ratio of a frame period of the second driving frequency is changed from an emission duty ratio of the first frame period of the second driving frequency to a target emission duty ratio of the frame period of the second driving frequency.

10. The display device according to claim 9, wherein: During the plurality of frame periods of the second driving frequency, the emission duty ratio of the frame period of the second driving frequency gradually changes.

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