Methods for display devices and sensing driving characteristics

Abstract

A display device and a method for sensing driving characteristics are provided. The display device includes a sensing circuit and a controller for selecting a row of pixels in a frame period. A vertical blank period in the frame period includes a sensing time in which the sensing circuit performs a sensing operation for the selected row of pixels. The sensing circuit measures a first source voltage of a driving transistor of a pixel in the selected row of pixels at a first point in the sensing time, and measures a second source voltage of the driving transistor at a second point in the sensing time. The controller calculates a threshold voltage parameter and a mobility parameter based on the first and second source voltages, predicts a saturation source voltage of the driving transistor based on the threshold voltage parameter and the mobility parameter, and calculates a threshold voltage of the driving transistor based on the saturation source voltage.

Description

Technical Field

[0001] Embodiments of the invention relate to a display device, and more specifically, to a display device for performing sensing operations and a method for sensing driving characteristics. Background Technology

[0002] Even when multiple pixels included in a display device (such as an organic light-emitting diode (“OLED”) display device) are manufactured using the same process, the driving transistors of the multiple pixels will have different driving characteristics due to process variations, etc. Therefore, the multiple pixels will emit light with different brightness. Furthermore, as the OLED display device is driven over time, the multiple pixels will degrade, and the driving characteristics of the driving transistors will also deteriorate. To compensate for the initial non-uniformity and degradation of brightness, the OLED display device can perform a sensing operation that senses the driving characteristics of the driving transistors of the multiple pixels.

[0003] In order to accurately sense the driving characteristics of the driving transistors of multiple pixels, sufficient sensing time (e.g., tens of milliseconds) is required for the source voltage of the driving transistors to saturate. Therefore, sensing operations cannot be performed in real time while the display device (e.g., an organic light-emitting diode (“OLED”) display device) is displaying an image. Summary of the Invention

[0004] Some embodiments provide a display device capable of performing sensing operations on the driving characteristics of a sensing drive transistor in real time.

[0005] Some embodiments provide a method for sensing the driving characteristics of a driving transistor in real time.

[0006] An embodiment provides a display device, comprising: a display panel including a plurality of pixel rows; a scan driver providing scan signals and sensing signals to corresponding pixel rows among the plurality of pixel rows; a data driver coupled to the plurality of pixel rows via a plurality of data lines; a sensing circuit coupled to the plurality of pixel rows via a plurality of sensing lines; and a controller controlling the scan driver, the data driver, and the sensing circuit, and selecting pixel rows from the plurality of pixel rows during a frame period. A vertical blank period of the frame period includes a sensing time during which the sensing circuit performs a sensing operation on the selected pixel row. The sensing circuit measures a first source voltage of a driving transistor of a pixel in the selected pixel row at a first point in the sensing time, and measures a second source voltage of the driving transistor at a second point in the sensing time. The controller calculates a threshold voltage parameter and a mobility parameter based on the first and second source voltages, predicts a saturation source voltage of the driving transistor based on the threshold voltage parameter and the mobility parameter, and calculates the threshold voltage of the driving transistor based on the saturation source voltage.

[0007] In an embodiment, a pixel may include: a driving transistor, including a gate, a source, and a drain for receiving a first power supply voltage; a first switching transistor, including a gate for receiving a scan signal, a drain connected to one of a plurality of data lines, and a source connected to the gate of the driving transistor; a second switching transistor, including a gate for receiving a sensing signal, a drain connected to the source of the driving transistor, and a source connected to one of a plurality of sensing lines; a storage capacitor, including a first electrode connected to the gate of the driving transistor and a second electrode connected to the source of the driving transistor; and a light-emitting element, including an anode connected to the source of the driving transistor and a cathode for receiving a second power supply voltage.

[0008] In this embodiment, the threshold voltage parameter can be calculated by subtracting the reference voltage from the first source voltage.

[0009] In one embodiment, the gate voltage of the driving transistor can be fixed as the sensing data voltage from the start point of the sensing time to the second time point.

[0010] In an embodiment, the data driver can apply a sensing data voltage to multiple data lines during the sensing time, the scan driver can apply a scan signal to a selected pixel row during the sensing time, the sensing circuit can apply a reference voltage to multiple sensing lines from the start time of the sensing time to a third time point before the first time point, and the scan driver applies a sensing signal to the selected pixel row from the third time point to the end time of the sensing time.

[0011] In this embodiment, the mobility parameter can be calculated using the following equation:

[0012]

[0013] Where β represents the mobility parameter, T1 represents the first time point, T2 represents the second time point, Vs(T1) represents the first source voltage, Vs(T2) represents the second source voltage, Vg represents the sensed data voltage, and Vth represents the threshold voltage of the driving transistor obtained through the previous sensing operation.

[0014] In this embodiment, the saturation source voltage can be predicted using the following equation:

[0015]

[0016] Where SVs represents the saturation source voltage, γ represents the threshold voltage parameter, and β represents the mobility parameter.

[0017] In this embodiment, the threshold voltage of the driving transistor can be calculated by subtracting the saturation source voltage from the sensed data voltage.

[0018] In an embodiment, the time from the start of the sensing time to the first time point can be approximately 200 microseconds (μs), and the time from the first time point to the second time point can be approximately 10 microseconds.

[0019] In one embodiment, the gate voltage of the driving transistor can be fixed as the sensed data voltage from the start of the sensing time to a first time point, and can be floating from the first time point to a second time point. The gate-source voltage of the driving transistor can be fixed from the first time point to the second time point.

[0020] In one embodiment, the data driver can apply a sensing data voltage to multiple data lines from the start of the sensing time to a first time point, the scan driver can apply a scan signal to a selected pixel row from the start of the sensing time to the first time point, the sensing circuit can apply a reference voltage to multiple sensing lines from the start of the sensing time to a third time point before the first time point, and the scan driver can apply a sensing signal to a selected pixel row from the third time point to a second time point.

[0021] In this embodiment, the mobility parameter can be calculated using the following equation:

[0022]

[0023] Where β represents the mobility parameter, T1 represents the first time point, T2 represents the second time point, Vs(T1) represents the first source voltage, Vs(T2) represents the second source voltage, Vgs(T1) represents the gate-source voltage of the driving transistor at the first time point, and Vth represents the threshold voltage of the driving transistor obtained through the previous sensing operation.

[0024] In an embodiment, the vertical blank period may include the previous data write time after the sensing time, during which the previous data voltage applied to the pixel in the effective period before the vertical blank period is applied to the pixel again.

[0025] In one embodiment, the display device may further include a characteristic parameter memory storing threshold voltages and mobility parameters of the driving transistors. The controller may calibrate input image data for pixels based on the threshold voltages and mobility parameters stored in the characteristic parameter memory.

[0026] An embodiment provides a method for sensing driving characteristics in a display device comprising a plurality of pixel rows. In this method: a pixel row is selected from the plurality of pixel rows during a frame period; a first source voltage of a driving transistor of a pixel in the selected pixel row is measured at a first time point during a sensing time within a vertical blank period of the frame period; a second source voltage of the driving transistor is measured at a second time point during the sensing time; a threshold voltage parameter is calculated based on the first source voltage; a mobility parameter is calculated based on the first and second source voltages; a saturation source voltage of the driving transistor is predicted based on the threshold voltage parameter and the mobility parameter; and a threshold voltage of the driving transistor is calculated based on the saturation source voltage.

[0027] In one embodiment, the gate voltage of the driving transistor can be fixed as the sensing data voltage from the start point of the sensing time to the second time point.

[0028] In this embodiment, the mobility parameter can be calculated using the following equation:

[0029]

[0030] Where β represents the mobility parameter, T1 represents the first time point, T2 represents the second time point, Vs(T1) represents the first source voltage, Vs(T2) represents the second source voltage, Vg represents the sensed data voltage, and Vth represents the threshold voltage of the driving transistor obtained through the previous sensing operation.

[0031] In this embodiment, the saturation source voltage can be predicted using the following equation:

[0032]

[0033] Where SVs represents the saturation source voltage, γ represents the threshold voltage parameter, and β represents the mobility parameter.

[0034] In one embodiment, the gate voltage of the driving transistor can be fixed as the sensed data voltage from the start of the sensing time to a first time point, and can be floating from the first time point to a second time point. The gate-source voltage of the driving transistor can be fixed from the first time point to the second time point.

[0035] In this embodiment, the mobility parameter can be calculated using the following equation:

[0036]

[0037] Where β represents the mobility parameter, T1 represents the first time point, T2 represents the second time point, Vs(T1) represents the first source voltage, Vs(T2) represents the second source voltage, Vgs(T1) represents the gate-source voltage of the driving transistor at the first time point, and Vth represents the threshold voltage of the driving transistor obtained through the previous sensing operation.

[0038] As described above, in the display device (e.g., OLED display device) and the method for sensing driving characteristics in the embodiments, the first source voltage and the second source voltage of the driving transistor of each pixel in the selected pixel row can be measured at a first time point and a second time point during the sensing time in the vertical blank period. A threshold voltage parameter and a mobility parameter can be calculated based on the first source voltage and the second source voltage. The saturation source voltage of the driving transistor can be predicted based on the threshold voltage parameter and the mobility parameter, and the threshold voltage of the driving transistor can be calculated based on the saturation source voltage. Therefore, since the saturation source voltage of the driving transistor after saturation is predicted using the first source voltage and the second source voltage before saturation, the sensing operation of sensing the driving characteristics (e.g., threshold voltage and / or mobility) of the driving transistor can be performed accurately and efficiently. Attached Figure Description

[0039] The illustrative, non-limiting embodiments will become clearer from the following detailed description taken in conjunction with the accompanying drawings.

[0040] Figure 1 This is a block diagram showing the display device.

[0041] Figure 2 This is a circuit diagram illustrating an embodiment of pixels included in a display device.

[0042] Figure 3 This is a diagram illustrating an embodiment of the source voltage variation over time for describing the sensing operation of a display device.

[0043] Figure 4 This is a flowchart illustrating a method for sensing driving characteristics in a display device.

[0044] Figure 5 This is a diagram used to illustrate an example of selecting the row of pixels to which sensing operations will be performed in each frame cycle.

[0045] Figure 6 This is a timing diagram used to describe an embodiment of the operation of a display device.

[0046] Figure 7 This is a diagram illustrating an embodiment of the equation used to predict the saturation source voltage in a method for sensing drive characteristics.

[0047] Figure 8 This is a diagram illustrating an embodiment based on the value of k of the gate-source voltage of the driving transistor.

[0048] Figure 9 This is a diagram illustrating an embodiment of the equation used to calculate the mobility parameter in a method for sensing driving characteristics.

[0049] Figure 10 This is a diagram illustrating an embodiment of the difference between the predicted saturation source voltage and the actual saturation source voltage based on the sensing time in a method for sensing drive characteristics.

[0050] Figure 11 This is a diagram illustrating an embodiment of the difference between the predicted saturation source voltage and the actual saturation source voltage based on the degree of degradation in a method for sensing drive characteristics.

[0051] Figure 12 This is a flowchart illustrating a method for sensing driving characteristics in a display device.

[0052] Figure 13 This is a timing diagram used to describe an embodiment of the operation of a display device.

[0053] Figure 14 This is a diagram illustrating an embodiment of the equation used to calculate the mobility parameter in a method for sensing driving characteristics.

[0054] Figure 15 This is a block diagram showing an electronic device including a display device. Detailed Implementation

[0055] In the following description, embodiments of the invention will be illustrated in detail with reference to the accompanying drawings.

[0056] The invention will now be described more fully below with reference to the accompanying drawings, in which various embodiments are illustrated. However, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The same reference numerals throughout denote the same elements.

[0057] What will be understood is that when an element is referred to as being "on" another element, the element may be directly on the other element, or there may be an intermediate element between them. Conversely, when an element is referred to as being "directly on" another element, there is no intermediate element.

[0058] 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 parts, these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or part from another element, component, region, layer, or part. Therefore, without departing from the teaching herein, “first element,” “first component,” “first region,” “first layer,” or “first part” discussed below may be referred to as a second element, second component, second region, second layer, or second part.

[0059] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” are intended to include the plural forms containing “at least 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 also be understood that when the terms “comprising” and / or “including” are used in this specification, it indicates the presence of the stated features, regions, integrals, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, regions, integrals, steps, operations, elements, components, and / or groups thereof.

[0060] Furthermore, relative terms such as “down” or “bottom” and “up” or “top” may be used herein to describe the relationship between one element and another as shown in the figures. It will be understood that, in addition to the orientations depicted in the figures, the relative terms are intended to include different orientations of the device. In an embodiment, when a device in one of the figures is flipped, an element described as being “down” to the other element will subsequently be positioned “up” to the other element. Thus, depending on the specific orientation in the figure, the exemplary term “down” can include both “down” and “up” orientations. Similarly, when a device in one of the figures is flipped, an element described as being “below” or “under” the other element will subsequently be positioned “above” the other element. Thus, the exemplary terms “below” or “under” can include both “up” and “down” orientations.

[0061] As used herein, “about” or “approximately” includes the stated value and means: within an acceptable deviation of the stated value as determined by one of ordinary skill in the art, taking into account the measurement in question and the error associated with the measurement of the particular quantity (i.e., the limitations of the measurement system). For example, “about” may mean within one or more standard deviations, or within ±30%, ±20%, ±10%, ±5% of the stated value.

[0062] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It will also be understood that terms (such as those defined in a general dictionary) shall be interpreted as having the same meaning as they have in the relevant field and in the context of the invention, and shall not be interpreted in an idealized or overly formal sense, unless expressly defined herein.

[0063] The embodiments are described herein with reference to cross-sectional views, which are schematic illustrations of idealized embodiments. Thus, variations in the shape of the illustrations will be expected, for example, due to manufacturing techniques and / or tolerances. Therefore, the embodiments described herein should not be construed as limited to the specific shapes of the areas shown herein, but will include, for example, deviations in shape due to manufacturing processes. In the embodiments, areas shown or described as flat may generally have rough and / or non-linear characteristics. Furthermore, acute angles (sharp corners) shown may be rounded (rounded). Therefore, the areas shown in the figures are schematic in nature, and their shapes are not intended to show the precise shapes of the areas, nor are they intended to limit the scope of the claims.

[0064] Figure 1 This is a block diagram illustrating an embodiment of the display device. Figure 2 This is a circuit diagram illustrating an embodiment of pixels included in an OLED display device, and Figure 3 This is a diagram illustrating an embodiment of the source voltage variation over time for describing the sensing operation of an OLED display device.

[0065] Reference Figure 1 The display device 100 in the embodiments (e.g., an organic light-emitting diode (“OLED”) display device) may include: a display panel 110 including a plurality of pixel rows, a scan driver 120 providing scan signals SC and sensing signals SS to corresponding pixel rows in the plurality of pixel rows, a data driver 130 coupled to the plurality of pixel rows via a plurality of data lines DL, a sensing circuit 140 coupled to the plurality of pixel rows via a plurality of sensing lines SL, and a controller 160 controlling the scan driver 120, the data driver 130, and the sensing circuit 140. In some embodiments, the display device 100 may further include a characteristic parameter memory 150, which stores driving characteristic parameters of the driving transistors of each pixel PX.

[0066] Display panel 110 may include multiple data lines DL, multiple sensing lines SL, and multiple pixel rows coupled to the data lines DL and sensing lines SL. Here, each pixel row may be a row of pixels PX, and pixels PX in the same pixel row may receive the same scan signal SC and the same sensing signal SS. Display panel 110 may also include multiple scan signal lines coupled to the multiple pixel rows and multiple sensing signal lines coupled to the multiple pixel rows respectively. In some embodiments, each pixel PX may include an OLED, and display panel 110 may be an OLED display panel. In other embodiments, each pixel PX may include any suitable light-emitting element, such as a quantum dot (QD) light-emitting element.

[0067] In an embodiment, such as Figure 2 As shown, each pixel PX may include, for example, a driving transistor TDR, a first switching transistor TSW1, a second switching transistor TSW2, a storage capacitor CST, and a light-emitting element EL.

[0068] The storage capacitor CST can store the data voltage VDAT (or sense data voltage VSD) transmitted via the data line DL and / or the sense line SL. In some embodiments, the storage capacitor CST may include a first electrode coupled to the gate of the driving transistor TDR and a second electrode coupled to the source of the driving transistor TDR.

[0069] The first switching transistor TSW1 can connect the data line DL to the first electrode of the storage capacitor CST in response to the scan signal SC. Therefore, the first switching transistor TSW1 can transmit the data voltage VDAT (or sensed data voltage VSD) of the data line DL to the first electrode of the storage capacitor CST in response to the scan signal SC. In some embodiments, the first switching transistor TSW1 may include a gate for receiving the scan signal SC, a drain connected to the data line DL, and a source connected to the first electrode of the storage capacitor CST and the gate of the driving transistor TDR.

[0070] The second switching transistor TSW2 can, in response to a sensing signal SS, connect the sensing line SL to the second electrode of the storage capacitor CST and the source of the driving transistor TDR. In some embodiments, the second switching transistor TSW2 may include a gate for receiving the sensing signal SS, a drain connected to the source of the driving transistor TDR, and a source connected to the sensing line SL. The sensing line SL may be connected to a line capacitor CL. In some embodiments, the line capacitor CL may be, but is not limited to, a parasitic capacitor of the sensing line SL.

[0071] The driving transistor TDR can generate a driving current based on the data voltage VDAT stored in the storage capacitor CST. In some embodiments, the driving transistor TDR may include a gate coupled to a first electrode of the storage capacitor CST, a drain receiving a first power supply voltage ELVDD (e.g., a high power supply voltage), and a source coupled to a second electrode of the storage capacitor CST and the drain of a second switching transistor TSW2.

[0072] The light-emitting element EL can emit light in response to a drive current generated by the drive transistor TDR. In some embodiments, the light-emitting element EL may include an anode coupled to the source of the drive transistor TDR and a cathode receiving a second power supply voltage ELVSS (e.g., a low power supply voltage).

[0073] Although Figure 2 An embodiment of pixel PX is shown, but the pixel PX of the display device 100 is not limited to... Figure 2 Examples of implementations.

[0074] The scan driver 120 can generate a scan signal SC and a sensing signal SS based on a scan control signal SCTRL from the controller 160, and can sequentially provide the scan signal SC and the sensing signal SS to a plurality of pixels PX by pixel row during the effective time period of each frame cycle. In some embodiments, the scan control signal SCTRL may include, but is not limited to, a start signal and a clock signal. In some embodiments, the scan driver 120 may be integrated or discretely disposed in the peripheral portion of the display panel 110. In other embodiments, the scan driver 120 may be implemented using one or more integrated circuits (“ICs”).

[0075] The data driver 130 can generate a data voltage VDAT based on the output image data ODAT received from the controller 160 and a data control signal DCTRL, and can provide the data voltage VDAT to a plurality of pixels PX during the effective period of each frame cycle. In some embodiments, the data driver 130 can provide a sensed data voltage VSD to pixels PX in a selected pixel row during the vertical blank period of each frame cycle. The data control signal DCTRL may include a data enable signal DE (see reference). Figure 5 and Figure 6The data enable signal DE periodically transitions during the active period to notify the data driver 130 of the transmission timing of the output image data ODAT, and has a low level during the vertical blank period. In some embodiments, the data control signal DCTRL may also include, but is not limited to, a horizontal start signal and a load signal. In some embodiments, the data driver 130 and the controller 160 may be implemented using at least one single IC, and this single IC may be referred to as a timing controller embedded data driver (“TED”) IC. In other embodiments, the data driver 130 and the controller 160 may be implemented using separate ICs.

[0076] Sensing circuit 140 can provide a reference voltage VREF to a selected row of pixels for which sensing operations are performed via multiple sensing lines SL, and can receive the source voltage Vs of the driving transistor TDR of the pixel PX in the selected pixel row via the multiple sensing lines SL. In some embodiments, sensing circuit 140 may include a first switch 141 that provides the reference voltage VREF to the sensing lines SL in response to a reference signal SREF, a second switch 142 that connects the sensing lines SL to an analog-to-digital converter (“ADC”) 143 in response to a sampling signal SSAM, and an ADC 143 that converts the source voltage Vs received via the sensing lines SL into a digital signal. In some embodiments, sensing circuit 140 may include one ADC 143 for each sensing line SL. In other embodiments, sensing circuit 140 may include one ADC 143 for each plurality of sensing lines SL (e.g., every four, eight, or sixteen sensing lines SL), and the ADC 143 may perform analog-to-digital conversion operations on the source voltage Vs of the plurality of sensing lines SL in a time-division manner. In some embodiments, the sensing circuit 140 may be implemented using an IC that is separate from the IC of the data driver 130. In other embodiments, the sensing circuit 140 may be included in the data driver 130 or may be included in the controller 160.

[0077] The characteristic parameter memory 150 can store the driving characteristic parameters of the driving transistor TDR for each pixel PX. In some embodiments, the sensing circuit 140 can measure a first source voltage Vs(T1) at a first time point and a second source voltage Vs(T2) at a second time point by performing a sensing operation on the selected pixel row during the sensing time period in each vertical blank period. The controller 160 can calculate the threshold voltage parameter and mobility parameter of the driving transistor TDR based on the first source voltage Vs(T1) and the second source voltage Vs(T2). The characteristic parameter memory 150 can store the threshold voltage parameter and mobility parameter of the driving transistor TDR. In other embodiments, the controller 160 can predict the saturation source voltage of the driving transistor TDR based on the threshold voltage parameter and mobility parameter, and can calculate the threshold voltage of the driving transistor TDR based on the predicted saturation source voltage. The characteristic parameter memory 150 can store the threshold voltage and mobility parameter of the driving transistor TDR.

[0078] Controller 160 (e.g., a timing controller (“TCON”)) may receive input image data IDAT and control signal CTRL from an external main processor (e.g., a graphics processing unit (“GPU”), application processor (“AP”), or graphics card). In some embodiments, the control signal CTRL may include, but is not limited to, a vertical synchronization signal, a horizontal synchronization signal, an input data enable signal, a master clock signal, etc. Controller 160 may generate output image data ODAT, a data control signal DCTRL, and a scan control signal SCTRL based on drive characteristic parameters stored in characteristic parameter memory 150, the input image data IDAT, and the control signal CTRL. In some embodiments, characteristic parameter memory 150 may store threshold voltage and mobility parameters of the drive transistor TDR, and controller 160 may generate output image data ODAT by correcting the input image data IDAT based on the threshold voltage and mobility parameters of the drive transistor TDR stored in characteristic parameter memory 150. In an embodiment, for example, controller 160 may generate output image data ODAT representing the data voltage VDAT, in which a threshold voltage stored in characteristic parameter memory 150 is added to the voltage corresponding to the input image data IDAT. Furthermore, for example, controller 160 may generate output image data ODAT such that the data voltage VDAT decreases as the mobility parameter increases and increases as the mobility parameter decreases. Controller 160 may control the operation of scan driver 120 by providing scan control signal SCTRL to scan driver 120, and may control the operation of data driver 130 by providing output image data ODAT and data control signal DCTRL to data driver 130.

[0079] In embodiments of the display device 100, the controller 160 may select, in each frame cycle, a pixel row from a plurality of pixel rows of the display panel 110 to which a sensing operation is to be performed. In some embodiments, the controller 160 may sequentially select a plurality of pixel rows in multiple frame cycles, such that the pixel row to which the sensing operation is to be performed changes in each frame cycle. In other embodiments, the controller 160 may randomly select, in each frame cycle, a pixel row from a plurality of pixel rows of the display panel 110 to which the sensing operation is to be performed.

[0080] The vertical blank period of each frame cycle may include the sensing time during which the sensing circuit 140 performs sensing operations on the selected pixel row. Therefore, the sensing circuit 140 can perform sensing operations on the selected pixel row during the sensing time within the vertical blank period. To perform the sensing operation, at the beginning of the sensing time, a sensing data voltage VSD can be applied to the gate of the driving transistor TDR of each pixel PX in the selected pixel row via the data line DL and the first switching transistor TSW1, and a reference voltage VREF can be applied to the sensing line SL. Subsequently, when the second switching transistor TSW2 is turned on in response to the sensing signal SS, the source of the driving transistor TDR can be coupled to the sensing line SL. In this case, as... Figure 3 As shown, the source voltage Vs of the driving transistor TDR can be gradually increased from the reference voltage VREF and can saturate to a saturation source voltage SVs corresponding to the voltage obtained by subtracting the threshold voltage Vth of the driving transistor TDR from the sensing data voltage VSD. In conventional display devices, to sense the threshold voltage Vth of the driving transistor TDR, the source voltage Vs of the driving transistor TDR can be measured after the source voltage Vs of the driving transistor TDR saturates to the saturation source voltage SVs. However, the saturation point TSAT at which the source voltage Vs of the driving transistor TDR saturates to the saturation source voltage SVs is later than the end time of the vertical blank period VBP of each frame period, so the sensing operation of a conventional display device may not be possible within the vertical blank period VBP. Therefore, conventional display devices cannot perform sensing operations in real time while displaying an image.

[0081] However, in an embodiment of the display device 100, the sensing circuit 140 can measure the first source voltage Vs(T1) of the driving transistor TDR for each pixel PX in the selected pixel row at a first time point T1 of the sensing time ST within the vertical blank period VBP, and can measure the second source voltage Vs(T2) of the driving transistor TDR at a second time point T2 of the sensing time ST within the vertical blank period VBP. The controller 160 can receive the first source voltage Vs(T1) and the second source voltage Vs(T2) from the sensing circuit 140, can calculate a threshold voltage parameter and a mobility parameter based on the first source voltage Vs(T1) and the second source voltage Vs(T2), can predict the saturation source voltage SVs of the driving transistor TDR based on the threshold voltage parameter and the mobility parameter, and can calculate the threshold voltage Vth of the driving transistor TDR based on the saturation source voltage SVs. Therefore, in the embodiment of the display device 100, since the sensing circuit 140 measures the first source voltage Vs(T1) and the second source voltage Vs(T2) at the first time point T1 and the second time point T2 respectively before the saturation time point TSAT, and predicts the saturation source voltage SVs based on the first source voltage Vs(T1) and the second source voltage Vs(T2), the sensing operation through the sensing circuit 140 can be performed during the vertical blank period VBP, and the sensing operation through the sensing circuit 140 can be performed in real time while the display device 100 displays the image.

[0082] As described above, in the embodiment of the display device 100, the first source voltage Vs(T1) and the second source voltage Vs(T2) of the driving transistor TDR for each pixel PX in the selected pixel row can be measured at a first time point T1 and a second time point T2 within the sensing time ST during the vertical blank period VBP, respectively. A threshold voltage parameter and a mobility parameter can be calculated based on the first source voltage Vs(T1) and the second source voltage Vs(T2). The saturation source voltage SVs of the driving transistor TDR can be predicted based on the threshold voltage parameter and the mobility parameter. Furthermore, the threshold voltage Vth of the driving transistor TDR can be calculated based on the saturation source voltage SVs. Therefore, since the saturation source voltage SVs of the driving transistor TDR after saturation can be predicted using the first source voltage Vs(T1) and the second source voltage Vs(T2) before saturation of the driving transistor TDR, a sensing operation that senses the driving characteristics (e.g., the threshold voltage Vth and / or mobility) of the driving transistor TDR can be performed accurately and efficiently in real time.

[0083] Figure 4 This is a flowchart illustrating an embodiment of a method for sensing driving characteristics in a display device. Figure 5 This is a diagram used to illustrate an example of selecting the row of pixels to be sensed in each frame period. Figure 6 This is a timing diagram used to describe an embodiment of the operation of a display device. Figure 7 This is a diagram illustrating an embodiment of the equation used to predict the saturation source voltage in a method for sensing drive characteristics. Figure 8 This is a diagram illustrating an embodiment based on the value of k of the gate-source voltage of the driving transistor. Figure 9 This is a diagram illustrating an embodiment of the equation used to calculate the mobility parameter in a method for sensing driving characteristics. Figure 10 This is a diagram illustrating an embodiment of a method for describing the difference between the predicted saturation source voltage and the actual saturation source voltage based on the sensing time in a sensing drive characteristic method. Figure 11 This is a diagram illustrating an embodiment of the difference between the predicted saturation source voltage and the actual saturation source voltage based on the degree of degradation in a method for sensing drive characteristics.

[0084] Reference Figures 1 to 4 In an embodiment of the method for sensing driving characteristics in the display device 100, the controller 160 may select, in each frame cycle, a pixel row to which a sensing operation is to be performed (S210) from a plurality of pixel rows of the display panel 110. In some embodiments, a plurality of pixel rows may be selected sequentially during multiple frame cycles. In embodiments, for example, such as Figure 5As shown, the display panel 110 may include N pixel rows PXR1, PXR2, ..., PXRN, where N is an integer greater than 1. The controller 160 may sequentially select the first pixel row to the Nth pixel row PXR1, PXR2, ..., PXRN during the first frame period to the Nth frame period FP1, FP2, ..., FPN, in the order from the first pixel row PXR1 to the Nth pixel row PXRN. Each frame period FP1, FP2, ..., FPN and FPN+1 may include an active time period AP and a vertical blank time period VBP. During the active time period AP, the data enable signal DE periodically changes, and during the vertical blank time period VBP, the data enable signal DE is fixed at a low level. The sensing circuit 140 can perform a sensing operation on the first pixel row PXR1 during the sensing time ST within the vertical blank period VBP of the first frame period FP1, and can perform a sensing operation on the second pixel row PXR2 during the sensing time ST within the vertical blank period VBP of the second frame period FP2. In this way, a sensing operation can be performed on the Nth pixel row PXRN during the sensing time ST within the vertical blank period VBP of the Nth frame period FPN. Furthermore, the controller 160 can select the first pixel row PXR1 again in the (N+1)th frame period FPN+1, and the sensing circuit 140 can perform a sensing operation on the first pixel row PXR1 again during the sensing time ST within the vertical blank period VBP of the (N+1)th frame period FPN+1. In other embodiments, the controller 160 can randomly select the pixel row to be sensed from a plurality of pixel rows of the display panel 110 in each frame period.

[0085] The gate voltage of the driving transistor TDR for each pixel PX in the selected pixel row can be fixed as the sensing data voltage VSD during the sensing time ST within the vertical blank period VBP (e.g., from the start of the sensing time ST to the second time point T2). The sensing circuit 140 can measure the first source voltage Vs(T1) of the driving transistor TDR at the first time point T1 of the sensing time ST (S220), and can measure the second source voltage Vs(T2) of the driving transistor TDR at the second time point T2 of the sensing time ST (S230).

[0086] In an embodiment, for example, such as Figure 6As shown, the vertical blank period VBP may include a sensing time ST in which sensing operations are performed on the selected pixel row. At the start time TS of the sensing time ST, the scan driver 120 may provide a scan signal SC with a high level to the selected pixel row, and the data driver 130 may apply a sensing data voltage VSD to multiple data lines DL. The sensing data voltage VSD may be any voltage higher than the reference voltage VREF. In embodiments, for example, the sensing data voltage VSD may be, but is not limited to, a 255 grayscale voltage, a 128 grayscale voltage, etc. The first switching transistor TSW1 of each pixel PX in the selected pixel row may be turned on in response to the scan signal SC with a high level, and the first switching transistor TSW1 may transfer the voltage V_DL of the data line DL or the sensing data voltage VSD to the gate of the driving transistor TDR and the first electrode of the storage capacitor CST. Therefore, the driving transistor TDR may have a gate voltage corresponding to the sensing data voltage VSD. Furthermore, the sensing circuit 140 may apply a reference voltage VREF to multiple sensing lines SL, and the line capacitors CL of the multiple sensing lines SL may be pre-charged to the reference voltage VREF. In some embodiments, the reference voltage VREF may be (but is not limited to) about 0 volts (V). In an embodiment, for example, the first switch 141 of the sensing circuit 140 may be turned on in response to a reference signal SREF having a high level, and the reference voltage VREF may be applied to the sensing line SL through the first switch 141.

[0087] After a predetermined time from the start time point TS of the sensing time ST, or at a third time point T3 before the first time point T1, the sensing circuit 140 may stop applying the reference voltage VREF to the multiple sensing lines SL, and the scan driver 120 may provide a sensing signal SS with a high level to the selected pixel row. In an embodiment, for example, the first switch 141 of the sensing circuit 140 may be turned off in response to the reference signal SREF with a low level, and the reference voltage VREF may not be applied to the sensing lines SL. Furthermore, the second switching transistor TSW2 of each pixel PX in the selected pixel row may be turned on in response to the sensing signal SS with a high level, and the second switching transistor TSW2 may connect the source of the driving transistor TDR to the sensing line SL.

[0088] Since the voltage V_DL of the data line DL is the sensed data voltage VSD, and the scan signal SC is high, the gate voltage of the driving transistor TDR can be fixed at the sensed data voltage VSD. The driving transistor TDR can be turned on based on the sensed data voltage VSD. The drain-source current of the driving transistor TDR can flow to the line capacitor CL of the sense line SL through the second switching transistor TSW2, and the voltage of the sense line SL can gradually increase until the driving transistor TDR is turned off. Since the source of the driving transistor TDR is coupled to the sense line SL, the source voltage Vs of the driving transistor TDR can be substantially the same as the voltage of the sense line SL. Therefore, the voltage of the sense line SL or the source voltage Vs of the driving transistor TDR can gradually increase until the source voltage Vs saturates to a saturation source voltage SVs, which corresponds to the voltage obtained by subtracting the threshold voltage Vth of the driving transistor TDR from the sensed data voltage VSD.

[0089] Before the source voltage Vs saturates to the saturation source voltage SVs, the sensing circuit 140 can measure the first source voltage Vs(T1) of the driving transistor TDR at the first time point T1 by measuring the voltage of the sensing line SL at the first time point T1 of the sensing time ST, and can measure the second source voltage Vs(T2) of the driving transistor TDR at the second time point T2 by measuring the voltage of the sensing line SL at the second time point T2 of the sensing time ST. In some embodiments, the time from the start time point TS of the sensing time ST to the first time point T1 can be, but is not limited to, about 200 microseconds (μs), and the time from the first time point T1 to the second time point T2 can be, but is not limited to, about 10 μs. In an embodiment, for example, the second switch 142 of the sensing circuit 140 can be turned on at the first time point T1 in response to a sampling signal SSAM with a high level, the ADC 143 of the sensing circuit 140 can convert the voltage of the sensing line SL into a digital signal at the first time point T1, and the controller 160 can receive the first source voltage Vs(T1) in digital signal form from the sensing circuit 140. Furthermore, the second switch 142 of the sensing circuit 140 can be turned on at the second time point T2 in response to a sampling signal SSAM with a high level, the ADC 143 of the sensing circuit 140 can convert the voltage of the sensing line SL into a digital signal at the second time point T2, and the controller 160 can receive the second source voltage Vs(T2) in the form of a digital signal from the sensing circuit 140.

[0090] As described above, the data driver 130 can apply a sensing data voltage VSD to multiple data lines DL during the sensing time ST (e.g., from the start time point TS of the sensing time ST to the end time point TE of the sensing time ST), and the scan driver 120 can apply a scan signal SC to the selected pixel row during the sensing time ST (e.g., from the start time point TS of the sensing time ST to the end time point TE of the sensing time ST, or from the start time point TS of the sensing time ST to a second time point T2). Therefore, the gate voltage of the driving transistor TDR can be fixed to the sensing data voltage VSD during the sensing time ST (e.g., from the start time point TS of the sensing time ST to the second time point T2). Furthermore, the sensing circuit 140 can apply a reference voltage VREF to multiple sensing lines SL from the start time point TS of the sensing time ST to a third time point T3, and the scan driver 120 can apply a sensing signal SS to the selected pixel row from the third time point T3 to the end time point TE of the sensing time ST. Therefore, the voltage of the sensing line SL or the source voltage Vs of the driving transistor TDR can be gradually increased until the source voltage Vs saturates to the saturation source voltage SVs, which corresponds to the voltage obtained by subtracting the threshold voltage Vth of the driving transistor TDR from the sensing data voltage VSD. The sensing circuit 140 can measure the first source voltage Vs(T1) and the second source voltage Vs(T2) of the driving transistor TDR at the first time point T1 and the second time point T2, respectively, before the source voltage Vs saturates to the saturation source voltage SVs.

[0091] In some embodiments, the vertical blank period VBP may further include an initialization time INIT during which the sensing line SL and / or the data line DL are initialized. During the initialization time INIT, a reference voltage VREF may be applied to the sensing line SL. In an embodiment, for example, a first switch 141 of the sensing circuit 140 may be turned on in response to a reference signal SREF having a high level, and the reference voltage VREF may be applied to the sensing line SL through the first switch 141. Furthermore, during the initialization time INIT, the reference voltage VREF or another initialization voltage may be applied to the data line DL.

[0092] In some embodiments, the vertical blank period VBP may further include a preceding data write time PDWT after the sensing time ST or after the initialization time INIT, in which the preceding data voltage PVDAT applied to pixel PX in the effective period AP preceding the vertical blank period VBP is applied to pixel PX again. In the preceding data write time PDWT, scan driver 120 may apply a high-level scan signal SC and a high-level sensing signal SS to the selected pixel row to which sensing operations are performed, sensing circuit 140 may apply a reference voltage VREF to multiple sensing lines SL, and data driver 130 may apply the preceding data voltage PVDAT for the selected pixel row to multiple data lines DL. Therefore, the preceding data voltage PVDAT may be stored in each pixel PX of the selected pixel row in the preceding data write time PDWT, and pixel PX may emit light based on the preceding data voltage PVDAT in the next effective period AP until the next data voltage VDAT is provided in that next effective period AP.

[0093] The controller 160 can receive a first source voltage Vs(T1) and a second source voltage Vs(T2) from the sensing circuit 140. It can calculate a threshold voltage parameter based on the first source voltage Vs(T1) (S240), calculate a mobility parameter based on the first source voltage Vs(T1) and the second source voltage Vs(T2) (S250), predict the saturation source voltage SVs of the driving transistor TDR based on the threshold voltage parameter and the mobility parameter (S260), and calculate the threshold voltage Vth of the driving transistor TDR based on the saturation source voltage SVs (S270).

[0094] In some embodiments, such as Figure 7 As shown, the threshold voltage parameter γ can be calculated by subtracting the reference voltage VREF (or Vs(0)) from the first source voltage Vs(T1). Furthermore, in some embodiments, the reference voltage VREF (or Vs(0)) can be approximately 0V, and the threshold voltage parameter γ can be the first source voltage Vs(T1). Additionally, in some embodiments, as... Figure 9 As shown, the mobility parameter β can be calculated using the following equation:

[0095]

[0096] Where β can represent the mobility parameter, T1 can represent the first time point, T2 can represent the second time point, Vs(T1) can represent the first source voltage, Vs(T2) can represent the second source voltage, Vg can represent the sensed data voltage VSD, and Vth can represent the threshold voltage of the driving transistor TDR obtained through the previous sensing operation. Furthermore, in some embodiments, such as... Figure 7 As shown, the saturation source voltage SVs can be predicted by the following equation:

[0097]

[0098] Where SVs can represent the saturation source voltage, γ can represent the threshold voltage parameter, and β can represent the mobility parameter. Furthermore, in some embodiments, such as... Figure 7 As shown, the threshold voltage Vth of the driving transistor TDR can be calculated by subtracting the saturation source voltage SVs from the sensing data voltage VSD.

[0099] In an embodiment, such as Figure 7 As shown, the drain-source current of the driving transistor TDR can be determined by equation 310:

[0100]

[0101] For example, I ds (t) can represent the drain-source current of the driving transistor TDR, μ n C can represent the mobility of the driving transistor TDR. ox Vgs(t) represents the capacitance per unit area of ​​the driving transistor TDR, W represents the channel width of the driving transistor TDR, L represents the channel length of the driving transistor TDR, Vgs(t) represents the gate-source voltage of the driving transistor TDR, and Vth represents the threshold voltage of the driving transistor TDR. When the effective voltage "Veff(t)" is replaced with "Vgs(t)-Vth", and "k" is used as the denoting variable, the threshold voltage of the driving transistor TDR is determined. Then, equation 310 can be simplified to equation 320:

[0102] I ds (t)=k·Veff(t) 2 ,

[0103] Where Veff(t) can represent the effective voltage, and k can represent the transconductance parameter of the driving transistor TDR.

[0104] The amount of charge Q stored in the line capacitor CL of the sensing line SL can be expressed by equation 330, Q = C. line ·Vs” is determined. Here, Q can represent the amount of charge stored in the online capacitor CL, Cline Vc can represent the capacitance of the line capacitor CL, and Vs can represent the source voltage of the driving transistor TDR. Since the gate voltage of the driving transistor TDR is fixed, "Veff(t)" can be "Vgs(t)-Vth = Vg-Vs(t)-Vth". Therefore, when differentiating both sides of equation 330 with respect to time t, equation 330 can be transformed into equation 340:

[0105]

[0106] Since the drain-source current of the driving transistor TDR is applied to the line capacitor CL, equation 320 can be essentially equal to equation 340, therefore equation 350 can be derived as follows:

[0107]

[0108] When solving the differential equation for “Veff(t)” based on Equation 350, Equation 360 can be extracted as follows:

[0109]

[0110] Here, Vg can represent the gate voltage of the driving transistor TDR or the sensed data voltage VSD, and Vs(0) can be the source voltage of the driving transistor TDR before its increase, or the source voltage of the driving transistor TDR at the start time point TS or the third time point T3. Since “Veff(t)” is “Vgs(t)-Vth=Vg-Vs(t)-Vth”, the following equation 365 can be extracted from equation 360:

[0111]

[0112] When modifying Equation 365 relative to “Vth”, replace it with the mobility parameter β. Furthermore, by substituting “Vs(t)-Vs(0)” with the threshold voltage parameter γ, equation 370 can be extracted as follows:

[0113]

[0114] in, This can be the saturation source voltage SVs of the driving transistor TDR. The source voltage of the driving transistor TDR before its increase, or the source voltage of the driving transistor TDR at the start time point TS or the third time point T3, can be the reference voltage VREF. Therefore, when the reference voltage VREF is approximately 0V, the saturation source voltage SVs can be as shown in Equation 380. When Equation 380 is modified, the saturation source voltage SVs can be as shown in Equation 390. Here, γ can represent the threshold voltage parameter or Vs(t), and β can represent the mobility parameter.

[0115] like Figure 8 As shown, “k” (i.e., The transconductance parameter β can be non-constant, but rather a variable that changes according to the gate-source voltage Vgs of the driving transistor TDR. Therefore, "k" (e.g., the transconductance parameter of the driving transistor TDR) can be expressed as "k(Vgs(t))". The mobility parameter β can be determined by "k(Vgs(t))" and can be expressed as follows: Figure 9 The calculation is shown in the figure.

[0116] like Figure 9 As shown, when for Figure 9 Equation 410 (or Figure 7 When taking the derivative of equation 330 with respect to time t and approximating it, equation 420 can be extracted as follows:

[0117] I ds (t)·Δt=C line ·ΔVs.

[0118] When equation 425 (or Figure 7 Equation 320) "I ds (t)=k(Vgs(t))·(Vgs(t)-Vth) 2 Substituting into equation 420, we can extract equation 430 as follows:

[0119]

[0120] Here, ΔVs can represent the source voltage difference of the driving transistor TDR, and Δt can represent the time difference. When the difference between the first source voltage Vs(T1) and the second source voltage Vs(T2) is substituted into ΔVs, and the difference between the first time point T1 and the second time point T2 is substituted into Δt, since the gate voltage Vg of the driving transistor TDR is fixed, and the second time point T2 is substantially immediately after the first time point T1 (e.g., about 10 μs after the first time point T1), Equation 440 can be derived from Equation 430 as follows:

[0121]

[0122] Furthermore, due to equation 445 To determine the mobility parameter β, when equation 440 is substituted into equation 445, equation 450 can be extracted as follows:

[0123]

[0124] Wherein, β can represent a mobility parameter, T1 can represent a first time point, T2 can represent a second time point, Vs(T1) can represent a first source voltage, Vs(T2) can represent a second source voltage, Vg can represent the gate voltage of the driving transistor TDR or the sensing data voltage VSD, and Vth can represent the threshold voltage of the driving transistor TDR obtained through the previous sensing operation. In some embodiments, when calculating the mobility parameter β, the threshold voltage Vth of the driving transistor TDR of pixel PX, measured during the manufacture of display device 100, can be used for the first sensing operation performed after the manufacture of display device 100. During the manufacture of display device 100, the threshold voltage Vth of the driving transistor TDR can be measured after the source voltage Vs saturates to the saturation source voltage SVs. Furthermore, in subsequent sensing operations for pixel PX, the threshold voltage Vth of the driving transistor TDR of pixel PX is directly obtained or calculated through the previous sensing operation.

[0125] As mentioned above, it can be done through Figure 9 Equation 450 is used to calculate the mobility parameter β:

[0126]

[0127] In addition, it can be done through Figure 7 Equation 390 defines the threshold voltage parameter γ as the first source voltage Vs(T1). Based on the mobility parameter β and the threshold voltage parameter γ, it can be determined by... Figure 7 Equation 390 predicts the saturation source voltage SVs of the driving transistor TDR:

[0128]

[0129] Therefore, the saturation source voltage SVs of the driving transistor TDR after saturation can be predicted using the first source voltage Vs(T1) and the second source voltage Vs(T2) before saturation. The saturation source voltage SVs predicted by the sensing drive characteristics method in the embodiment can be substantially the same as or similar to the actual saturation source voltage. Furthermore, it can be predicted by... Figure 7 Equation 370 can be used to calculate the threshold voltage Vth of the driving transistor TDR, or by subtracting the saturation source voltage SVs from the sensed data voltage VSD.

[0130] Figure 10 Graphs 510, 530, and 550 are shown. Graph 510 shows the pass-through of the driving transistor TDR in the first case where the sensing time ST is approximately 100 μs. Figure 7Equation 390 shows the difference between the predicted and actual saturation source voltages. Figure 530 illustrates the difference between the predicted and actual saturation source voltages of the driving transistor TDR in the second case where the sensing time ST is approximately 200 μs. Figure 550 illustrates the difference between the predicted and actual saturation source voltages of the driving transistor TDR in the third case where the sensing time ST is approximately 300 μs. Figure 10 As shown, in the first case where the sensing time ST can be approximately 100 μs, the average difference (or average error) between the predicted saturation source voltage and the actual saturation source voltage is approximately 0.023 V; in the second case where the sensing time ST is approximately 200 μs, the average error is approximately 0.010 V; and in the third case where the sensing time ST is approximately 300 μs, the average error is approximately 0.005 V. Furthermore, as... Figure 10 As shown, in the second case where the sensing time ST is approximately 200 μs, the difference (or error) between the predicted saturation source voltage and the actual saturation source voltage can be less than an acceptable or tolerable error. Therefore, in some embodiments, the sensing time ST can be, but is not limited to, approximately 200 μs or approximately 210 μs.

[0131] also, Figure 11 The pass rate is shown according to the degree of degradation. Figure 7 An example of the difference between the predicted saturation source voltage and the actual saturation source voltage according to Equation 390. Figure 11 In the embodiments shown in Table 610, a degradation level of 1 can represent the driving transistor TDR (refer to...). Figure 2 No degradation. Degradation level 2 can be defined as a degradation of the driving transistor TDR such that, compared to degradation level 1, the threshold voltage Vth increases by approximately 0.4V and the mobility μ decreases by approximately 9.11%. Degradation level 3 can be defined as a degradation of the driving transistor TDR such that, compared to degradation level 1, the threshold voltage Vth increases by approximately 0.8V and the mobility μ decreases by approximately 18.15%. Figure 11 As shown in graph 630, in all three degradation levels (1, 2, and 3), the difference (or error) between the predicted saturation source voltage and the actual saturation source voltage can be less than or equal to approximately 0.01V. Therefore, the saturation source voltage predicted by the sensing drive characteristics method in the embodiment can be substantially the same as the actual saturation source voltage.

[0132] As described above, in embodiments of the method for sensing driving characteristics, the vertical blank period VBP (refer to) can be used respectively. Figure 6 The sensing time ST within ) (refer to) Figure 6 The first time point T1 and the second time point T2 (refer to) Figure 3 and Figure 6) Measure the first source voltage Vs(T1) and the second source voltage Vs(T2) of the driving transistor TDR for each pixel PX in the selected pixel row (refer to) Figure 3 and Figure 6 The threshold voltage parameter γ and mobility parameter β can be calculated based on the first source voltage Vs(T1) and the second source voltage Vs(T2). The saturation source voltage SVs of the driving transistor TDR can then be predicted based on the threshold voltage parameter γ and the mobility parameter β (see reference). Figure 3 Furthermore, the threshold voltage Vth of the driving transistor TDR can be calculated based on the saturation source voltage SVs. Therefore, since the saturation source voltage SVs of the driving transistor TDR after saturation is predicted by the first source voltage Vs(T1) and the second source voltage Vs(T2) before saturation of the driving transistor TDR, the sensing operation of sensing the driving characteristics (e.g., threshold voltage Vth and / or mobility) of the driving transistor TDR can be performed accurately and efficiently in real time.

[0133] Figure 12 This is a flowchart illustrating an embodiment of a method for sensing driving characteristics in a display device. Figure 13 This is a timing diagram used to describe an embodiment of the operation of a display device, and Figure 14 This is a diagram illustrating an embodiment of the equation used to calculate the mobility parameter in a method for sensing driving characteristics.

[0134] Except that the gate-source voltage of the driving transistor, rather than the gate voltage of the driving transistor, is fixed from the first time point of the sensing time to the second time point of the sensing time, Figure 12 The method can be with Figure 4 The method is similar.

[0135] Reference Figures 1 to 3 as well as Figures 12 to 14In an embodiment of the method for sensing driving characteristics in the display device 100, the controller 160 can select, in each frame cycle, a pixel row from a plurality of pixel rows of the display panel 110 to which a sensing operation is to be performed (S710). The gate voltage of the driving transistor TDR of each pixel PX in the selected pixel row can be fixed to the sensing data voltage VSD from the start time point TS of the sensing time ST within the vertical blank period VBP to a first time point T1, and the sensing circuit 140 can measure the first source voltage Vs(T1) of the driving transistor TDR at the first time point T1 of the sensing time ST (S720). The gate-source voltage of the driving transistor TDR can be fixed from the first time point T1 to a second time point T2 by floating the gate of the driving transistor TDR and the sensing circuit 140, and the second source voltage Vs(T2) of the driving transistor TDR can be measured at the second time point T2 of the sensing time ST (S730).

[0136] In an embodiment, such as Figure 13 As shown, for example, data driver 130 can apply a sensing data voltage VSD to multiple data lines from the start time point TS of sensing time ST to the first time point T1, and scan driver 120 can apply a scan signal SC to the selected pixel row from the start time point TS of sensing time ST to the first time point T1. Therefore, the gate voltage of the driving transistor TDR can be fixed to the sensing data voltage VSD from the start time point TS of sensing time ST to the first time point T1. In addition, sensing circuit 140 can apply a reference voltage VREF to multiple sensing lines SL from a third time point T3 before the first time point T1 from the start time point TS of sensing time ST, and the line capacitors CL of the multiple sensing lines SL can be pre-charged to the reference voltage VREF. After the third time point T3, the voltage of the sensing line SL or the source voltage Vs of the driving transistor TDR can be gradually increased until the source voltage Vs saturates to a saturation source voltage SVs, which corresponds to the voltage obtained by subtracting the threshold voltage Vth of the driving transistor TDR from the sensing data voltage VSD. Before the source voltage Vs saturates to the saturation source voltage SVs, the sensing circuit 140 can measure the first source voltage Vs(T1) of the driving transistor TDR at the first time point T1 by measuring the voltage of the sensing line SL at the first time point T1 of the sensing time ST.

[0137] At the first time point T1 of the sensing time ST, the scan driver 120 can change the scan signal SC to a low level. Therefore, the gate-source voltage of the driving transistor TDR can be fixed by floating the gate of the driving transistor TDR from the first time point T1 to the second time point T2 (or until the end time point TE of the sensing time ST). The sensing circuit 140 can measure the second source voltage Vs(T2) of the driving transistor TDR at the second time point T2 by measuring the voltage of the sensing line SL at the second time point T2 of the sensing time ST.

[0138] In some embodiments, the vertical blank period VBP may further include a previous data write time PDWT after the sensing time ST, in which the previous data voltage PVDAT applied to pixel PX during the effective period AP before the vertical blank period VBP is applied to pixel PX again. In some embodiments, the vertical blank period VBP may further include, as Figure 6 The initialization time INIT shown is between the sensing time ST and the previous data write time PDWT.

[0139] The controller 160 can receive a first source voltage Vs(T1) and a second source voltage Vs(T2) from the sensing circuit 140. It can calculate a threshold voltage parameter based on the first source voltage Vs(T1) (S740), calculate a mobility parameter based on the first source voltage Vs(T1) and the second source voltage Vs(T2) (S750), predict a saturation source voltage SVs based on the threshold voltage parameter and the mobility parameter (S760), and calculate the threshold voltage Vth of the driving transistor TDR based on the saturation source voltage SVs (S770).

[0140] In some embodiments, such as Figure 14 As shown, when the difference between the first source voltage Vs(T1) and the second source voltage Vs(T2) is substituted into ΔVs, and the difference between the first time point T1 and the second time point T2 is substituted into Δt, since the gate-source voltage Vgs(t) of the driving transistor TDR is fixed from the first time point T1 to the second time point T2, it can be obtained from equation 810 (or Figure 9 Equation 430) is extracted into equation 820 as follows:

[0141]

[0142] Furthermore, due to equation 830 To determine the mobility parameter β, when equation 820 is substituted into equation 830, equation 840 can be extracted as follows:

[0143]

[0144] Where β can represent the mobility parameter, T1 can represent the first time point, T2 can represent the second time point, Vs(T1) can represent the first source voltage, Vs(T2) can represent the second source voltage, Vgs(T1) can represent the gate-source voltage of the driving transistor TDR at the first time point, and Vth can represent the threshold voltage of the driving transistor TDR obtained through the previous sensing operation.

[0145] Therefore, it can be done Figure 14 Equation 840 is used to calculate the mobility parameter β:

[0146]

[0147] In addition, it can be done through Figure 7 Equation 390 defines the threshold voltage parameter γ as the first source voltage Vs(T1). Based on the mobility parameter β and the threshold voltage parameter γ, it can be determined by... Figure 7 Equation 390 predicts the saturation source voltage SVs of the driving transistor TDR:

[0148]

[0149] Therefore, the saturation source voltage SVs of the driving transistor TDR after saturation can be predicted by the first source voltage Vs(T1) and the second source voltage Vs(T2) before saturation. Furthermore, it can be predicted by... Figure 7 Equation 370 can be used to calculate the threshold voltage Vth of the driving transistor TDR, or by subtracting the saturation source voltage SVs from the sensed data voltage VSD.

[0150] As described above, in an embodiment of the method for sensing driving characteristics, the first source voltage Vs(T1) and the second source voltage Vs(T2) of the driving transistor TDR for each pixel PX in the selected pixel row can be measured at a first time point T1 and a second time point T2 within the sensing time ST during the vertical blank period VBP. A threshold voltage parameter γ and a mobility parameter β can be calculated based on the first source voltage Vs(T1) and the second source voltage Vs(T2). The saturation source voltage SVs of the driving transistor TDR can be predicted based on the threshold voltage parameter γ and the mobility parameter β. Furthermore, the threshold voltage Vth of the driving transistor TDR can be calculated based on the saturation source voltage SVs. Therefore, since the saturation source voltage SVs of the driving transistor TDR after saturation can be predicted using the first source voltage Vs(T1) and the second source voltage Vs(T2) before saturation, the sensing operation of sensing the driving characteristics (e.g., threshold voltage Vth and / or mobility) of the driving transistor TDR can be performed accurately and efficiently in real time.

[0151] Figure 15 This is a block diagram illustrating an embodiment of an electronic device including a display device.

[0152] Reference Figure 15 Electronic device 1100 may include a processor 1110, a memory device 1120, a storage device 1130, an input / output (“I / O”) device 1140, a power supply 1150, and a display device 1160. Electronic device 1100 may also include multiple ports for communicating with video cards, sound cards, memory cards, universal serial bus (“USB”) devices, other electronic devices, etc.

[0153] Processor 1110 can perform various computing functions or tasks. In embodiments, processor 1110 may be, for example, an application processor (“AP”), a microprocessor, a central processing unit (“CPU”), etc. In embodiments, processor 1110 may be integrated with other components via address buses, control buses, data buses, etc. Furthermore, in some embodiments, processor 1110 may also be integrated with an expansion bus such as a peripheral component interconnect (“PCI”) bus.

[0154] The memory device 1120 may store data for the operation of the electronic device 1100. In embodiments, the memory device 1120 may include at least one non-volatile 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, a ferroelectric random access memory (“FRAM”) device, etc.) and / or at least one volatile memory device (such as a dynamic random access memory (“DRAM”) device, a static random access memory (“SRAM”) device, a mobile dynamic random access memory (mobile “DRAM”) device, etc.).

[0155] In this embodiment, for example, storage device 1130 may be a solid-state drive (“SSD”) device, a hard disk drive (“HDD”) device, a CD-ROM device, etc. I / O device 1140 may be an input device such as a keyboard, keypad, mouse, touchscreen, etc., and an output device such as a printer, speaker, etc. Power supply 1150 provides power for the operation of electronic device 1100. Display device 1160 may be connected to other components via a bus or other communication link.

[0156] In the display device 1160, the first source voltage and the second source voltage of the driving transistor of each pixel in the selected pixel row can be measured at a first time point and a second time point during the sensing time in the vertical blank period. A threshold voltage parameter and a mobility parameter can be calculated based on the first source voltage and the second source voltage. The saturation source voltage of the driving transistor can be predicted based on the threshold voltage parameter and the mobility parameter. Furthermore, the threshold voltage of the driving transistor can be calculated based on the saturation source voltage. Therefore, since the saturation source voltage of the driving transistor after saturation can be predicted using the first source voltage and the second source voltage before saturation, a sensing operation that senses the driving characteristics (e.g., threshold voltage and / or mobility) of the driving transistor can be performed accurately and efficiently.

[0157] Embodiments of the invention can be applied to any electronic device 1100 including display device 1160. In embodiments, for example, the invention can be applied to televisions (“TV”), digital TVs, 3D TVs, smartphones, wearable electronic devices, tablet computers, mobile phones, personal computers (“PC”), home appliances, laptop computers, personal digital assistants (“PDAs”), portable multimedia players (“PMPs”), digital cameras, music players, portable game consoles, navigation devices, etc.

[0158] The foregoing is illustrative of the embodiments and is not to be construed as limiting the embodiments. Although some embodiments have been described, it will be readily understood by those skilled in the art that many modifications can be made to the embodiments without substantially departing from the novel teachings and advantages of the invention. Therefore, all such modifications are intended to be included within the scope of the invention as defined in the claims. It will therefore be understood that the foregoing is illustrative of various embodiments and is not to be construed as limiting to the specific embodiments disclosed, and modifications to the disclosed embodiments and other embodiments are intended to be included within the scope of the appended claims.

Claims

1. A display device, the display device comprising: The display panel includes multiple pixel rows; A scan driver provides scan signals and sensing signals to corresponding pixel rows in the plurality of pixel rows; A data driver that connects to the multiple pixel rows via multiple data lines; The sensing circuit is connected to the multiple pixel rows via multiple sensing lines; as well as The controller controls the scan driver, the data driver, and the sensing circuit, and selects a pixel row from the plurality of pixel rows during the frame period. The vertical blank period of the frame period includes the sensing time, during which the sensing circuit performs a sensing operation on the selected pixel row. Specifically, the sensing circuit measures the first source voltage of the driving transistor of the pixel in the selected pixel row at a first time point of the sensing time, and measures the second source voltage of the driving transistor at a second time point of the sensing time. The controller calculates a threshold voltage parameter and a mobility parameter based on the first time point, the second time point, the first source voltage, and the second source voltage; predicts the saturation source voltage of the driving transistor based on the threshold voltage parameter and the mobility parameter; and calculates the threshold voltage of the driving transistor based on the saturation source voltage.

2. The display device according to claim 1, wherein, The pixels include: The driving transistor includes a gate, a source, and a drain that receives a first power supply voltage. The first switching transistor includes a gate for receiving the scan signal, a drain connected to one of the plurality of data lines, and a source connected to the gate of the driving transistor. The second switching transistor includes a gate for receiving the sensing signal, a drain connected to the source of the driving transistor, and a source connected to one of the plurality of sensing lines. A storage capacitor includes a first electrode coupled to the gate of the driving transistor and a second electrode coupled to the source of the driving transistor; and The light-emitting element includes an anode coupled to the source of the driving transistor and a cathode that receives a second power supply voltage.

3. The display device according to claim 1, wherein, The threshold voltage parameter is calculated by subtracting the reference voltage from the first source voltage.

4. The display device according to claim 1, wherein, The gate voltage of the driving transistor is fixed as the sensing data voltage from the start time of the sensing time to the second time point.

5. The display device according to claim 1, wherein, The data driver applies the sensed data voltage to the plurality of data lines during the sensing time. The scan driver applies the scan signal to the selected pixel row during the sensing time. Specifically, the sensing circuit applies a reference voltage to the plurality of sensing lines from the start time of the sensing time to a third time point prior to the first time point, and The scan driver applies the sensing signal to the selected pixel row from the third time point to the end of the sensing time.

6. The display device according to claim 1, wherein, The mobility parameter is calculated using the following equation: , Wherein, β represents the mobility parameter, T1 represents the first time point, T2 represents the second time point, Vs(T1) represents the first source voltage, Vs(T2) represents the second source voltage, Vg represents the sensing data voltage, and Vth represents the threshold voltage of the driving transistor obtained through the previous sensing operation.

7. The display device according to claim 1, wherein, The saturation source voltage is predicted by the following equation: ， Wherein, SVs represents the saturation source voltage, γ represents the threshold voltage parameter, and β represents the mobility parameter.

8. The display device according to claim 1, wherein, The threshold voltage of the driving transistor is calculated by subtracting the saturation source voltage from the sensed data voltage.

9. The display device according to claim 1, wherein, The time from the start of the sensing time to the first time point is 200 microseconds, and The time from the first time point to the second time point is 10 microseconds.

10. The display device according to claim 1, wherein, The gate voltage of the driving transistor is fixed as the sensing data voltage from the start time of the sensing time to the first time point, and is floating from the first time point to the second time point. The gate-source voltage of the driving transistor is fixed from the first time point to the second time point.

11. The display device according to claim 1, wherein, The data driver applies the sensed data voltage to the plurality of data lines from the start time of the sensing time to the first time point. The scan driver applies the scan signal to the selected pixel row from the start time of the sensing time to the first time point. Specifically, the sensing circuit applies a reference voltage to the plurality of sensing lines from the start time of the sensing time to a third time point prior to the first time point, and The scan driver applies the sensing signal to the selected pixel row from the third time point to the second time point.

12. The display device according to claim 1, wherein, The mobility parameter is calculated using the following equation: ， Wherein, β represents the mobility parameter, T1 represents the first time point, T2 represents the second time point, Vs(T1) represents the first source voltage, Vs(T2) represents the second source voltage, Vgs(T1) represents the gate-source voltage of the driving transistor at the first time point, and Vth represents the threshold voltage of the driving transistor obtained through the previous sensing operation.

13. The display device according to claim 1, wherein, The vertical blank period includes the previous data write time after the sensing time, during which the previous data voltage applied to the pixel in the effective period before the vertical blank period is applied to the pixel again.

14. The display device according to claim 1, wherein, The display device further includes: A characteristic parameter memory stores the threshold voltage and mobility parameter of the driving transistor. The controller corrects the input image data for the pixel based on the threshold voltage and the mobility parameter stored in the characteristic parameter memory.

15. A method for sensing driving characteristics in a display device comprising a plurality of pixel rows, the method comprising: Select a pixel row from the plurality of pixel rows during the frame period; The first source voltage of the driving transistor of the pixel in the selected pixel row is measured at a first time point during the sensing time within the vertical blank period of the frame period. The second source voltage of the driving transistor is measured at a second time point of the sensing time. The threshold voltage parameter is calculated based on the first source voltage; Mobility parameters are calculated based on the first time point, the second time point, the first source voltage, and the second source voltage. The saturation source voltage of the driving transistor is predicted based on the threshold voltage parameter and the mobility parameter. as well as The threshold voltage of the driving transistor is calculated based on the saturation source voltage.

16. The method according to claim 15, wherein, The gate voltage of the driving transistor is fixed as the sensing data voltage from the start time of the sensing time to the second time point.

17. The method according to claim 15, wherein, The mobility parameter is calculated using the following equation: , Wherein, β represents the mobility parameter, T1 represents the first time point, T2 represents the second time point, Vs(T1) represents the first source voltage, Vs(T2) represents the second source voltage, Vg represents the sensing data voltage, and Vth represents the threshold voltage of the driving transistor obtained through the previous sensing operation.

18. The method according to claim 15, wherein, The saturation source voltage is predicted by the following equation: ， Wherein, SVs represents the saturation source voltage, γ represents the threshold voltage parameter, and β represents the mobility parameter.

19. The method according to claim 15, wherein, The gate voltage of the driving transistor is fixed as the sensing data voltage from the start time of the sensing time to the first time point, and is floating from the first time point to the second time point. The gate-source voltage of the driving transistor is fixed from the first time point to the second time point.

20. The method of claim 15, wherein, The mobility parameter is calculated using the following equation: ， Wherein, β represents the mobility parameter, T1 represents the first time point, T2 represents the second time point, Vs(T1) represents the first source voltage, Vs(T2) represents the second source voltage, Vgs(T1) represents the gate-source voltage of the driving transistor at the first time point, and Vth represents the threshold voltage of the driving transistor obtained through the previous sensing operation.

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