Source driver and display device including the thereof

Abstract

A source driver and a display device including the source driver are disclosed, the source driver being able to improve sensing accuracy even when providing a black image signal to reduce motion blur during a sensing period of a signal used to sense pixels of a display panel. The source driver includes: an output buffer configured to output a source signal; a voltage terminal to which a black image signal having a preset voltage level is applied; a source output terminal connected to a data line of the display panel; and a switching circuit configured to connect one of the output terminal of the output buffer and the voltage terminal to the source output terminal, wherein the switching circuit connects the voltage terminal to the source output terminal during a black image insertion period of the sensing period of a pixel of the display panel.

Description

Technical Field

[0001] Various implementations generally relate to display devices, and more specifically, to source drivers having a black-and-white image insertion function and display devices including the source driver. Background Technology

[0002] With the development of the information society, the demand for display devices for displaying images is increasing, and various types of display devices, such as liquid crystal displays and organic light-emitting diode displays, are being utilized.

[0003] Among these display devices, organic light-emitting display devices use self-emissive organic light-emitting diodes (OLEDs), and therefore have a fast response time, as well as advantages in contrast, luminous efficiency, brightness, and viewing angle.

[0004] This organic light-emitting display device includes organic light-emitting diodes (OLEDs) disposed in each of a plurality of pixels arranged in a display panel, and the organic light-emitting display device can display an image by controlling the brightness of each pixel by controlling the current flowing through the organic light-emitting diodes.

[0005] Motion blur may occur in such organic light-emitting display devices. Motion blur refers to the phenomenon where an image becomes partially blurred due to the limited response speed during the display process on the display panel, depending on the speed of movement of objects included in the image.

[0006] Recently, black data interpolation technology has been applied to reduce motion blur in organic light-emitting display devices. Black data interpolation inserts black images between driving images. To do this, black data representing black images can be inserted between display data representing driving images.

[0007] In organic light-emitting display devices, organic light-emitting diodes (OLEDs) and driving transistors for driving the OLEDs can be disposed in each of the pixels in the display panel. The characteristic values ​​of each pixel (such as the threshold voltage or mobility of the driving transistor) may vary over time, and due to differences in usage time between pixels, the characteristic values ​​of the pixels may deviate. Because of this fact, brightness variations may occur between pixels.

[0008] To address brightness discrepancies between pixels, organic light-emitting display devices are configured to sense and compensate for deviations in pixel feature values.

[0009] The feature values ​​of a pixel can be sensed by the sensing circuitry of the source driver, and compensation for deviations in the display data can be performed by a timing controller. However, when a sensing error occurs due to unexpected reasons, there is a problem of anomalies appearing in the displayed image.

[0010] During the sensing period used to sense the feature values ​​of a pixel, when black data is inserted, sensing errors may occur due to the transition of the source signal through the black data. In other words, noise caused by the transition of the source signal may be introduced into the sensing circuit of the source driver.

[0011] Furthermore, depending on whether black data is inserted during the sensing period or not, the pixel's feature value exhibits sensing bias. Summary of the Invention

[0012] Various embodiments are intended to provide a source driver and a display device including the source driver, which can provide a black image signal for reducing motion blur without causing noise during the sensing period for sensing the feature values ​​of pixels of the display panel, thereby improving sensing accuracy.

[0013] In one embodiment, the source driver may include: an output buffer configured to output a source signal; a voltage terminal with a preset voltage level applied; a source output terminal connected to a data line of the display panel; and a switching circuit configured to connect one of the output terminal of the output buffer and the voltage terminal to the source output terminal, wherein the switching circuit connects the voltage terminal to the source output terminal during a black image insertion period of a sensing period of a pixel of the display panel.

[0014] In one embodiment, the display device may include: a display panel; and a source driver configured to provide a source output to a pixel of the display panel, wherein the source driver provides a source output for displaying a driving image in which a black image is inserted, and wherein, during a black image insertion period in a sensing period of a pixel of the display panel, the source driver outputs a preset voltage level for displaying the black image as a source output.

[0015] According to the implementation, during the sensing period, the source driver can insert a black image signal to reduce motion blur while maintaining the level of the source signal.

[0016] According to the implementation, even when inserting a black image signal, the transition of the source signal in the source driver can be prevented. Therefore, noise can be prevented from being introduced into the sensing circuit of the source driver that senses the feature values ​​of the sensed pixels during the sensing period.

[0017] Furthermore, according to the implementation, since the transition of the source signal in the source driver is prevented during the sensing period, the sensing deviation of the pixel feature values ​​between the sensing period without the insertion of the black image signal and the sensing period with the insertion of the black image signal can be reduced, which makes it possible to improve the sensing accuracy.

[0018] Furthermore, according to the implementation, since it is not necessary to provide black data for inserting black images, the process of the timing controller controlling the source driver can be simplified. Attached Figure Description

[0019] Figure 1 This is a diagram illustrating a source driver according to an embodiment and a display device including the source driver.

[0020] Figure 2 This is a diagram that helps illustrate the black image insertion function in the source driver according to the implementation method.

[0021] Figure 3 yes Figure 2 The timing diagram shows the case where no black image is inserted.

[0022] Figure 4 yes Figure 2 A timing diagram showing the case where a black image is inserted. Detailed Implementation

[0023] The implementation discloses a source driver that can improve sensing accuracy even when inserting black images between driving images to reduce motion blur.

[0024] In this implementation, the display period can be defined as the period during which the source signal corresponding to the display data is output to the display panel as a source output. The source signal is a signal output from the output buffer (described later) in the source driver, and the source output is a signal output through the source signal output terminal of the source driver.

[0025] In an implementation, the sensing period can be defined as the period during which the sensing circuit of the source driver senses the feature values ​​of the pixels of the display panel.

[0026] A display period can be set for each frame that forms the driving image, and a sensing period can be set between display periods. This will be described later. Figure 2 In the diagram, the display period is represented by "D", and the sensing period is represented by "S".

[0027] In an implementation, the sensing period may include a sampling period and a conversion period. The sampling period may be defined as the period during which signals from the pixels of the display panel are sensed and sampled to sense the feature values ​​of the pixels, and the conversion period may be defined as the period during which the sampled signals generated by sensing the pixels are converted into digital signals.

[0028] In an implementation, the black image insertion period can be defined as the period during which a black image is inserted between driving images to reduce motion blur in the display device.

[0029] In this implementation, the black image insertion period may be included within the sensing period. More specifically, the black image insertion period may be included within the sampling period used to sense and sample the signal of the pixel. For example, during the sampling period of the sensing period, the black image insertion period may correspond to the period after the signal of the pixel has been sensed and sampled.

[0030] In implementation, terms such as "first" and "second" can be used to describe various components, but these components are not limited by these terms. Terms such as "first" and "second" may be used only for the purpose of distinguishing one component from other components.

[0031] Figure 1 This is a diagram illustrating a source driver according to an embodiment and a display device including the source driver.

[0032] The display device may include a display panel (PANEL), a source driver (SDIC), and a timing controller (not shown).

[0033] The display panel (PANEL) may include multiple gate lines (not shown), multiple data lines (DL), and multiple pixels. Pixels may be located in the areas where the gate lines and data lines (DL) intersect, and may be connected to sensing lines (SL).

[0034] Although for the sake of explanation, Figure 1 Only one pixel is shown, but the implementation is not limited to this. Each pixel may include a driving transistor DRT, a scanning transistor SCAN, a sensing transistor SEN, and a storage capacitor C. ST And organic light-emitting diodes (OLEDs). Control signals for switching the scan transistor (SCAN) and the sensing transistor (SEN) can be provided via the gate lines.

[0035] The driving transistor DRT can have a first node N1, a second node N2, and a third node N3.

[0036] The scan transistor SCAN can be connected to the first node N1 of the drive transistor DRT. When the scan transistor SCAN is turned on, the source output Vdata can be applied to the first node N1 via the data line DL.

[0037] The anode of an organic light-emitting diode (OLED) can be connected to the second node N2 of the driving transistor DRT, and the driving voltage terminal EVDD can be connected to the third node N3 of the driving transistor DRT.

[0038] Storage capacitor C ST It can be formed between the first node N1 and the second node N2 of the driving transistor DRT, and the level of the first node N1 can be maintained at the level of the source output Vdata.

[0039] As can be understood from the above, the source output Vdata is a signal output through the source output terminal 20 and is a signal provided to the data line DL by the switching circuit 30 of the source driver SDIC (described later).

[0040] The timing controller can convert data received from the host system into data types available in the source driver SDIC, provide display data and reference data to the source driver SDIC, and control the operation of the source driver SDIC.

[0041] The timing controller can provide display data to the source driver SDIC during the display period and reference data to the source driver SDIC during the sensing period. The reference data can be limited to data with preset values ​​corresponding to the sensing period.

[0042] The timing controller can receive digital data corresponding to the characteristics of the pixels of the display panel from the source driver SDIC, and can use the digital data to correct the display data.

[0043] The source driver SDIC can receive display data or reference data from the timing controller, convert the display data or reference data into an analog source signal, and provide the source signal as the source output Vdata to the data line DL of the display panel PANEL.

[0044] The source driver SDIC may include latching circuitry (not shown), a digital-to-analog converter (not shown), and an output buffer 10. The source driver SDIC may also include sensing circuitry for sensing and sampling signals from pixels received via sensing line SL. The sensing circuitry may include a sampling switch SAM and a sampling capacitor C. SAM And analog-to-digital converter (ADC).

[0045] The latch circuit can latch the display data, the digital-to-analog converter can convert the display data into a source signal, and the output buffer 10 can output the source signal.

[0046] In the sensing circuit, the sampling switch SAM and the sampling capacitor C SAM The signal from the sensing line SL can be sensed and sampled, and the analog-to-digital converter (ADC) can transfer the signal from the sampling capacitor C. SAM The sampled signal is converted into digital data.

[0047] The source driver SDIC can provide a black image signal as a source output Vdata to the data line DL of the display panel during the black image insertion period of the sensing period, in order to reduce motion blur. The black image signal is a signal with a preset voltage level to insert a black image. For example, a ground voltage can be provided as the black image signal.

[0048] Specifically, during the sensing period, the source driver SDIC can provide a source output Vdata corresponding to the reference data to the data line DL of the display panel PANEL from a first time t1 of the sampling period to a second time t2, the start of the black image insertion period of the sampling period. In this case, the source output Vdata of the source driver SDIC can be understood as the source signal of the output buffer 10 corresponding to the reference data. In embodiments of this disclosure, the first time t1 can be set as the start time of the sampling period. The sampling period, the first time t1, and the second time t2 can be referred to in the following description. Figure 4 To understand.

[0049] During the black image insertion period of the sensing period, the source driver SDIC can connect the ground terminal GND and the source output terminal 20, and thus, can provide a ground voltage as a black image signal to the data line DL of the display panel PANEL. In this case, the source output Vdata of the source driver SDIC can be understood as the ground voltage as the black image signal.

[0050] To switch the source output Vdata described above, the source driver SDIC may include a switching circuit 30, which may be configured between the output terminal of the output buffer 10, the ground terminal GND, and the source output terminal 20.

[0051] During the sensing period, the output buffer 10 buffers and outputs a source signal corresponding to the reference data from the first time t1 of the sampling period to the second time t2 when the black image insertion period of the sampling period begins. The source signal of the output buffer 10 can be output to the source output terminal 20 according to the switching circuit 30.

[0052] The ground voltage, serving as the black image signal, is applied to the ground terminal GND. During the black image insertion period of the sensing period, the ground voltage can be output to the source output terminal 20 according to the switching of the switching circuit 30.

[0053] The source output terminal 20 can be connected to the data line DL of the display panel PANEL, and can receive the source signal of the output buffer 10 or the ground voltage of the ground terminal GND according to the switching of the switching circuit 30. The signal received in the source output terminal 20 (i.e. the signal applied to the data line DL) is the source output Vdata.

[0054] The switching circuit 30 can connect one of the output terminal of the output buffer 10 and the ground terminal GND to the source output terminal 20.

[0055] The switching circuit 30 can connect the output terminal of the output buffer 10 to the source output terminal 20 from the first moment t1 at the start of the sampling period to the second moment t2 at the start of the black image insertion period, and can output the source signal corresponding to the reference data at the output terminal of the output buffer 10 as the source output Vdata.

[0056] During the black image insertion period, the switching circuit 30 can connect the ground terminal GND to the source output terminal 20, and thus can output the ground voltage of the ground terminal GND as the source output Vdata.

[0057] During the conversion period when the sampling signal of the pixel of the display panel is converted into a digital signal, the switching circuit 30 can maintain the connection between the ground terminal GND and the source output terminal 20.

[0058] When the sensing period ends and the display period begins, the switching circuit 30 can disconnect the connection between the ground terminal GND and the source output terminal 20, and can connect the connection between the output terminal of the output buffer 10 and the source output terminal 20.

[0059] The switching circuit 30 may include a first switch SW1 and a second switch SW2.

[0060] The first switch SW1 can connect the output terminal of the output buffer 10 to the source output terminal 20, and the second switch SW2 can connect the ground terminal GND to the source output terminal 20. When the first switch SW1 is turned on, the second switch SW2 can be turned off, and when the second switch SW2 is turned on, the first switch SW1 can be turned off.

[0061] When the sensing period does not include the black image insertion period, the switching circuit 30 can maintain the connection between the output terminal of the output buffer 10 and the source output terminal 20 during the sensing period.

[0062] When the sensing period includes a black image insertion period, the switching circuit 30 can connect the output terminal of the output buffer 10 to the source output terminal 20 from a first moment t1 at the start of the sampling period to a second moment t2 at the start of the black image insertion period. During the black image insertion period and the transition period, the switching circuit 30 can connect the ground terminal GND and the source output terminal 20.

[0063] Figure 2This diagram illustrates the black image insertion function in the source driver SDIC according to an embodiment. In the following text, the black image insertion period is represented by "BDI".

[0064] Reference Figure 2 There may be cases where the sensing period does not include the black image insertion period BDI (Case A) and cases where the sensing period includes the black image insertion period BDI (Case B).

[0065] In detail, in order to reduce motion blur, an organic light-emitting display device can perform a black-and-white image insertion drive that inserts black images through pixels other than those displaying image data thereon, thereby reducing dynamic picture response time (MPRT).

[0066] Black image insertion drive is a technology that displays a driving image on a display panel by providing a source signal corresponding to the display data via the data line DL and displaying a black image via other data lines DL or pixels without applied source signals.

[0067] Black image insertion drive prevents image blurring and improves image quality by displaying a drive image and a black image in the same frame.

[0068] Due to time constraints in both the image driver and the sensing driver, this black image insertion driver can be performed during the sensing period of the features of the sensing pixels.

[0069] In Case A, where the sensing period does not include the black image insertion period BDI, and in Case B, where the sensing period includes the black image insertion period BDI, the source driver SDIC can control the switching state of the switching circuit 30 differently.

[0070] Figure 3 yes Figure 2 The timing diagram for case A, which excludes the black image insertion period BDI, is shown in the sensing cycle.

[0071] Reference Figure 3 During the sensing period, the source driver SDIC can turn on the first switch SW1 and turn off the second switch SW2, thereby connecting the output terminal of the output buffer 10 and the source output terminal 20.

[0072] At this time, the source signal of output buffer 10 maintains a level corresponding to the level of the reference data. The source output Vdata applied to the data line DL through source output terminal 20 maintains the same level as the source signal. In other words, in Figure 3 In case A, the source signal output from output buffer 10 can remain at a fixed level without changing.

[0073] Figure 4yes Figure 2 The sensing period in the diagram includes the timing diagram of case B, where the black image insertion period is BDI.

[0074] Reference Figure 4 From the first moment t1 at the start of the sampling period of the sensing period to the second moment t2 at the start of the black image insertion period, the source driver SDIC can turn on the first switch SW1 and turn off the second switch SW2, thereby connecting the output terminal of the output buffer 10 and the source output terminal 20. At this time, the output buffer 10 of the source driver SDIC outputs the source signal corresponding to the reference data.

[0075] From the first moment t1 to the second moment t2, the source signal is provided to the source output terminal 20 through the opening of the first switch SW1, and the source output Vdata is output at the same level as the source signal.

[0076] During the black image insertion period BDI and transition period after the second time t2, the source driver SDIC can disconnect the first switch SW1 and turn on the second switch SW2, thereby connecting the ground terminal GND and the source output terminal 20.

[0077] During the black image insertion period (BDI) and transition period following the second time t2, the ground voltage is supplied to the source output terminal 20 via the switched-on second switch SW2, and the source output Vdata is output at the same level as the ground voltage. The source signal of the output buffer 10 of the source driver SDIC remains at a fixed level corresponding to the reference data without any transition.

[0078] In the embodiments described above, even when a black image is inserted during the sensing period, the source signal of the output buffer 10 can remain at a fixed level without transition. Therefore, the source driver SDIC according to embodiments of this disclosure can prevent noise caused by source signal transitions during sensing operation from being introduced into the sensing circuit. Thus, good sensing accuracy can be ensured.

[0079] Furthermore, since the source signal of the output buffer 10 remains at a fixed level without changing, the implementation described above can reduce the sensing deviation of the characteristic value between the sensing period in case A without black image insertion and the sensing period in case B with black image insertion, thereby improving the sensing accuracy.

[0080] Furthermore, the above implementation does not require changing the source output according to the time period of inserting the black image, thereby simplifying the process of the timing controller controlling the source driver.

Claims

1. A source driver comprising: an output buffer configured to output a source signal; a voltage terminal to which a preset voltage level is applied; a source output terminal connected to a data line of a display panel; and a switch circuit configured to connect one of an output terminal of the output buffer and the voltage terminal to the source output terminal, wherein, during a sampling period of a sensing period in which a pixel of the display panel is sensed, the switch circuit connects the output terminal of the output buffer and the source output terminal from a first time point at which the sampling period starts to a second time point at which a black image insertion period starts, and wherein, during the black image insertion period of the sampling period in which the pixel of the display panel is sensed, the switch circuit connects the voltage terminal to the source output terminal. The voltage terminal is a ground terminal that provides a ground voltage as a black image signal.

2. The source driver of claim 1, wherein, During a conversion period following the sampling period of the sensing period, the switch circuit maintains the connection of the voltage terminal and the source output terminal, in which a sampling signal generated by sensing the pixel is converted into a digital signal.

3. The source driver of claim 1, wherein, When the sensing period ends and a display period starts, the switch circuit disconnects the connection between the voltage terminal and the source output terminal, and connects the output terminal of the output buffer and the source output terminal.

4. The source driver of claim 1, wherein, The switch circuit comprises:

5. The source driver of claim 1, wherein, a first switch configured to switch the connection of the output terminal of the output buffer and the source output terminal; and a second switch configured to switch the connection of the voltage terminal and the source output terminal, wherein, when the first switch is connected, the second switch is disconnected, and wherein, when the second switch is connected, the first switch is disconnected. 6.The source driver of claim 1, wherein, during the black image insertion period of the sensing period including the black image insertion period and a conversion period in which a sampling signal generated by sensing the pixel is converted into a digital signal, the voltage terminal is connected to the source output terminal. 7.A display apparatus comprising: a display panel; and a source driver configured to provide a source output to a pixel of the display panel, wherein, during a sampling period of a sensing period in which the pixel of the display panel is sensed, the source driver provides the source output corresponding to reference data from a first time point at which the sampling period starts to a second time point at which a black image insertion period starts, and wherein, during the black image insertion period of the sampling period, the source driver provides the source output corresponding to a preset voltage level for displaying a black image. The source driver comprises: an output buffer configured to output a source signal; 8. The display device of claim 7, wherein, a voltage terminal to which the preset voltage level is applied; a source output terminal connected to a data line of the display panel; and a switch circuit configured to connect one of an output terminal of the output buffer and the voltage terminal to the source output terminal. ​ ​ 9. The display device according to claim 8, wherein during a sampling period of the sensing period, the switching circuit connects the output terminal of the output buffer and the source output terminal from a first time to a second time at the beginning of the black image insertion period.

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