Display device and method for driving the same

Abstract

The present disclosure relates to a display device and a method for driving the display device. Specifically, a display device according to an embodiment of the present disclosure includes a pixel, a sensing unit, and a compensator, the compensator calculates a current compensation value for each of the pixels based on a sensing value of the sensing unit, a first pixel of the pixels includes at least two light emitting diodes connected in series with a first transistor for controlling current, the sensing unit outputs a sensing value by sensing a voltage of the light emitting diodes during a sensing period, and the compensator increases the current compensation value for the first pixel as a voltage of a second node decreases during the sensing period.

Description

Technical Field

[0001] The present disclosure relates to a display device and a method for driving the display device. Background Art

[0002] As information technology develops, the importance of display devices as a connection medium between users and information is emphasized. In response to this, the use of display devices such as liquid crystal display devices, organic light emitting display devices, and plasma display devices is increasing.

[0003] The display device may include a plurality of pixels, and when light emitting diodes included in the plurality of pixels emit light having various colors and brightness, the display device may display various images.

[0004] A plurality of pixels may include a pixel circuit having substantially the same structure. However, as the size of the display device increases, process deviations may occur depending on the position of the pixel. Therefore, even transistors that perform the same function in each of the pixels may have different characteristics, such as mobility and threshold voltage. Similarly, the threshold voltage of the light-emitting diode of each pixel may be different from each other. In such a process, a technology is being developed for sensing characteristic information (mobility, threshold voltage, etc.) of the elements included in the pixel and compensating for characteristic information that changes according to degradation.

[0005] Meanwhile, recently, since light emitting diodes can be implemented in nanometer size to micrometer size, a plurality of light emitting diodes can be included in a pixel and emit light with high brightness. A display device including such light emitting diodes can display clearer images.

[0006] However, when a defective light emitting diode exists in a pixel due to a short circuit or the like in such a light emitting diode, there is a problem that the corresponding pixel may not emit light with required brightness and a brightness deviation may occur among a plurality of pixels.

[0007] Therefore, a technique for compensating the driving current is needed so that even if a light emitting diode is short-circuited, the corresponding pixel continues to emit light with appropriate brightness. Summary of the invention

[0008] Technical issues

[0009] An object to be solved by the present disclosure is to provide a display device and a method of driving the display device, which minimizes brightness deviation between pixels by allowing corresponding pixels to emit light with appropriate brightness even if a light emitting diode is short-circuited.

[0010] The objects of the present disclosure are not limited to the objects described above, and other technical objects not described will be clearly understood by those skilled in the art from the following description.

[0011] Technical Solution

[0012] In order to solve the above-mentioned purpose, on the one hand, a display device according to an embodiment of the present disclosure includes: a pixel; a sensing unit connected to the pixel through a sensing line; and a compensator configured to calculate a current compensation value for each of the pixels based on a sensing value of the sensing unit, wherein a first pixel in the pixels includes a first transistor, a first light-emitting diode, and a second light-emitting diode, the first transistor includes a gate electrode connected to a first node, a first electrode connected to a first power supply, and a second electrode connected to a second node, the first light-emitting diode includes a cathode and an anode connected to the second node, the second light-emitting diode includes an anode connected in series to the cathode of the first light-emitting diode and a cathode connected to the second power supply, the sensing unit outputs a sensing value by sensing a voltage of the second node during a sensing period, and the compensator increases the current compensation value for the first pixel as the voltage of the second node decreases during the sensing period.

[0013] Here, the first pixel may further include a second transistor and a third transistor, the second transistor including a gate electrode connected to the first scan line, a first electrode connected to the data line, and a second electrode connected to the first node, and the third transistor including a gate electrode connected to the second scan line, a first electrode connected to the second node, and a second electrode connected to the sensing line.

[0014] Here, a scan signal of an on level may be supplied to the first scan line during the display period, a scan signal of an off level may be supplied to the second scan line during the display period, and a data voltage may be supplied to the data line during the display period.

[0015] Here, a scan signal of an on level may be supplied to the first scan line during the sensing period, a scan signal of an on level may be supplied to the second scan line during the sensing period, and a sensing data voltage may be supplied to the data line during the sensing period.

[0016] Here, a scan signal of a conduction level may be provided to the first scan line during a sensing period, a scan signal of a conduction level may be provided to the second scan line during a sensing period, a sensing data voltage may be provided to the data line during a sensing period, and the voltage of the second power supply may be maintained in a state in which the voltage of the second power supply increases from a first level to a second level.

[0017] Here, the sensing unit may include: a first sensing transistor including a gate electrode connected to a first control line, a first electrode connected to a sensing line, and a second electrode connected to a third node; a second sensing transistor including a gate electrode connected to a second control line, a first electrode connected to a reference power supply, and a second electrode connected to a third node; a third sensing transistor including a gate electrode connected to the second control line, a first electrode connected to the sensing line, and a second electrode connected to a fourth node; a first resistor including a first terminal connected to the fourth node and a second terminal connected to a fifth node; a fourth sensing transistor including a gate electrode connected to the first control line, a first electrode connected to a reference power supply, and a second electrode connected to a fifth node; a second resistor including a first terminal connected to the fifth node and a second terminal connected to a sixth node; an amplifier including an output terminal, a first input terminal connected to the third node, and a second input terminal connected to the sixth node; and a third resistor including a first terminal connected to the sixth node and a second terminal connected to the output terminal.

[0018] Here, a control signal of an on level may be supplied to the first control line during the sensing period, and a control signal of an off level may be supplied to the second control line during the sensing period.

[0019] Here, the amplifier may output a first output voltage based on a voltage of the third node and a voltage of a reference power source.

[0020] Here, the compensator may calculate a variation amount of the voltage of the second node based on the first output voltage value of the first output voltage and a preset reference voltage value, and increase the current compensation value as the variation amount increases.

[0021] Here, the compensator may calculate a reduction ratio, which is a ratio of a sensed value of a voltage of a second node to a reference voltage value, extract compensation amount data corresponding to the reduction ratio data from a pre-stored lookup table, and calculate a current compensation value based on the extracted compensation amount data.

[0022] Here, the compensator may calculate the current compensation value based on a ratio of a reference voltage value to a sensed value of the voltage of the second node.

[0023] Here, a control signal of an off level may be supplied to the first control line during the sensing period, and a control signal of an on level may be supplied to the second control line during the sensing period.

[0024] Here, the amplifier may output a second output voltage based on the voltage of the fifth node and the voltage of the reference power supply.

[0025] Here, the compensator may calculate a variation amount of the sensed current, which is the current flowing through the second node, based on the second output voltage value of the second output voltage and a preset reference current value, and calculate the current compensation value based on the variation amount.

[0026] Here, the sensing unit may output a first sensing value by sensing a voltage of the second node during a first sensing period, and output a second sensing value by sensing a sensing current as a current flowing through the second node during a second sensing period not overlapping the first sensing period.

[0027] On the other hand, a method for driving a display device according to an embodiment of the present disclosure includes: a voltage sensing step of sensing a voltage applied to a plurality of light-emitting diodes included in a pixel; a defective light-emitting diode detection step of detecting whether a short-circuited defective light-emitting diode exists in the pixel based on the voltage and a preset reference voltage; and a current compensation value calculation step of calculating a current compensation value for the pixel when a defective light-emitting diode is detected and increasing the current compensation value as the voltage decreases.

[0028] Here, the pixel may include: a first transistor including a gate electrode connected to a first node, a first electrode connected to a first power supply, and a second electrode connected to a second node; a first light-emitting diode including a cathode and an anode connected to the second node; and a second light-emitting diode including an anode connected in series to the cathode of the first light-emitting diode and a cathode connected to the second power supply, and the voltage sensing step may sense the voltage of the second node.

[0029] Here, when the voltage of the second node is less than the reference voltage, the defective light emitting diode detecting step may determine that the defective light emitting diode exists.

[0030] Here, the current compensation value calculation step may calculate a change amount of the voltage of the second node based on the voltage of the second node and a reference voltage, and increase the current compensation value as the change amount increases.

[0031] Details of other implementations are included in the detailed description and accompanying drawings.

[0032] Beneficial Effects

[0033] As described above, embodiments of the present disclosure may provide a display device and a method of driving the display device, which minimizes brightness deviation between pixels by allowing corresponding pixels to emit light with appropriate brightness even if a light emitting diode is short-circuited.

[0034] The effects according to the embodiments are not limited to the contents of the above examples, and more various effects are included in this specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a block diagram schematically illustrating a display device according to an embodiment of the present disclosure.

[0036] Figure 2 It is shown Figure 1 An equivalent circuit diagram of an embodiment of a first pixel included in a display device.

[0037] Figure 3 It shows that in the display period Figure 2 A timing diagram of the operation of the first pixel emitting light.

[0038] Figure 4 It shows that in the display period Figure 2 An equivalent circuit diagram of the operation of the first pixel emitting light.

[0039] Figure 5 It is shown Figure 1 FIG. 1 is a diagram of a first pixel, a sensing unit, a compensator, and a memory included in a display device of FIG.

[0040] Figure 6 It is shown Figure 5 An equivalent circuit diagram of an implementation of a sensing unit.

[0041] Figure 7 is a diagram showing that in the first sensing period Figure 5 1 is a timing diagram of an operation of a sensing unit sensing a voltage.

[0042] Figure 8 is an exemplary illustration of the first sensing period. Figure 5 1 and 2. An equivalent circuit diagram of voltage and current generated in the first pixel.

[0043] Fig. 9 is a diagram showing that in the first sensing period Figure 6 An equivalent circuit diagram of an operation of the sensing unit sensing the voltage of the second node.

[0044] Fig.10 is a diagram showing that in the second sensing period Figure 5 A timing diagram of an operation of a sensing unit sensing current.

[0045] Fig.11 is an exemplary illustration of the second sensing period. Figure 5 1 and 2. An equivalent circuit diagram of voltage and current generated in the first pixel.

[0046] Fig.12 is a diagram showing that in the second sensing period Figure 6 1 is an equivalent circuit diagram of an operation of a sensing unit sensing a current of a first pixel.

[0047] Fig.132 is a diagram exemplarily showing a light source unit of the present disclosure.

[0048] Fig.14 is an exemplary illustration of the application to Fig.13 A diagram of the voltage and current of a light source unit.

[0049] Fig.15 and Fig.16 is a graph exemplarily showing a change in the magnitude of each of a voltage and a current applied to a light source unit when a light emitting diode is short-circuited.

[0050] Fig.17 is a flowchart illustrating a method of driving a display device according to an embodiment. DETAILED DESCRIPTION

[0051] Refer to the following and attached Figure 1 The advantages and features of the present disclosure and the methods for achieving them will become apparent from the detailed description of the embodiments. However, the present disclosure is not limited to the embodiments disclosed below, and the present disclosure can be implemented in various forms. The embodiments of the present disclosure are provided so that the present disclosure will be thorough and complete, and those skilled in the art to which the present disclosure belongs can fully understand the scope of the present disclosure, and the present disclosure is limited only by the scope of the claims.

[0052] Although first, second, etc. are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from another component. Therefore, the first component mentioned below can be a second component within the technical spirit of the present disclosure. Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0053] The following embodiments may be applied to various display devices such as an organic light emitting display device, a liquid crystal display device, a field emission display device, and an electrophoretic display device.

[0054] Hereinafter, embodiments of the present disclosure are described in detail with reference to the accompanying drawings. The same or similar reference numerals are used for the same components in the drawings.

[0055] Figure 1 is a block diagram schematically showing a display device 10 according to an embodiment of the present disclosure.

[0056] refer to Figure 1 The display device 10 according to an embodiment of the present disclosure may include a timing controller 11, a data driver 12, a scan driver 13, a display unit 14, a sensing unit 15, a compensator 16, a memory 17, and the like.

[0057] The timing controller 11 may receive various grayscale values ​​(or grayscale data) and control signals for each image frame from an external processor (not shown). The timing controller 11 may render grayscale values ​​to correspond to the specifications of the display device 10. For example, the external processor may provide a red grayscale value, a green grayscale value, and a blue grayscale value with respect to each unit dot. However, for example, when the display unit 14 has a PenTile structure, since adjacent unit dots share pixels, the pixels may not correspond to each grayscale value one-to-one, and the rendering of the grayscale value is necessary. When each pixel corresponds to each grayscale value one-to-one, the rendering of the grayscale value may be unnecessary. The rendered or unrendered grayscale value may be provided to the data driver 12. At the same time, the timing controller 11 may provide a control signal suitable for the corresponding specifications to the data driver 12 and the scan driver 13 for frame display. At the same time, the timing controller 11 may provide a control signal suitable for the specifications to the sensing unit 15 through the first control line C1 and the second control line C2 to indicate the sensing operation.

[0058] The data driver 12 may generate data voltages to be supplied to the data lines D1, D2, D3, and Dm by using grayscale values ​​and control signals. For example, the data driver 12 may sample grayscale values ​​using a clock signal and apply data voltages corresponding to the grayscale values ​​to the data lines D1 to Dm in a pixel row unit. m may be an integer greater than 0.

[0059] The scan driver 13 may receive a clock signal, a scan start signal, etc. from the timing controller 11 and generate a first scan signal to be supplied to the first scan lines S11, S12, and S1n and a second scan signal to be supplied to the second scan lines S21, S22, and S2n. n may be an integer greater than 0.

[0060] The scan driver 13 may sequentially supply a first scan signal having a pulse of an on level to the first scan lines S11, S12, and S1n. Also, the scan driver 13 may sequentially supply a second scan signal having a pulse of an on level to the second scan lines S21, S22, and S2n.

[0061] Although not shown, the scan driver 13 may include a first scan driver connected to the first scan lines S11, S12, and S1n and a second scan driver connected to the second scan lines S21, S22, and S2n. Each of the first scan driver and the second scan driver may include a scan stage configured in the form of a shift register. Each of the first scan driver and the second scan driver may generate a scan signal in a method of sequentially transmitting a scan start signal in the form of a pulse of a conduction level to a next scan stage according to the control of a clock signal.

[0062] According to an embodiment, the first scan signal and the second scan signal may be the same. In this case, the first scan line and the second scan line connected to each pixel may be connected to the same node. In this case, the scan driver 13 may not be divided into the first scan driver and the second scan driver, and may be configured as a single scan driver.

[0063] The display unit 14 may include pixels. Each of the pixels may be connected to corresponding data lines, scan lines, and sense lines. Figure 2 Describe this.

[0064] The sensing unit 15 may receive a control signal from the timing controller 11 and receive a sensing signal through each of the sensing lines I1, I2, I3, and Ip. For example, the sensing unit 15 may receive a sensing signal through the sensing lines I1, I2, I3, and Ip during at least a portion of the sensing period. p may be an integer greater than 0 and may be the same as m described above. The sensing unit 15 may be connected to the pixel through the sensing lines I1, I2, I3, and Ip.

[0065] Although not shown, the sensing unit 15 may include a sensing channel connected to the sensing lines I1, I2, I3, and Ip. For example, the sensing lines I1, I2, I3, and Ip and the sensing channel may correspond one-to-one.

[0066] Meanwhile, as in the present embodiment, the data driver 12 and the sensing unit 15 may be separately configured. However, in another embodiment, the data driver 12 and the sensing unit 15 may be integrally configured.

[0067] The sensing unit 15 may sense a sensing current or a sensing voltage and output its sensing value. Here, the sensing value (or sensing data) may be a digital value and may mean a sensing current value for sensing current, or may mean a sensing voltage value for sensing voltage. Meanwhile, the sensing voltage may mean a voltage of a specific node connected to the light emitting diode, as will be described later. Figures 5 to 9 Described.

[0068] As an embodiment, the sensing unit 15 can measure a sensing voltage according to a sensing current flowing through each of the pixels and output a first sensing value. Specifically, the timing controller 11 provides a control signal of an on level through the first control line C1, and provides a control signal of an off level through the second control line C2. In addition, the sensing unit 15 can sense a sensing voltage generated from at least one light emitting diode included in each of the pixels during a first sensing period according to a control signal provided from the timing controller 11, and output a first sensing value as a sensing voltage value.

[0069] As another embodiment, the sensing unit 15 may measure the sensing current for each pixel and output a second sensing value. Specifically, the timing controller 11 provides a control signal of an off level through the first control line C1, and provides a control signal of an on level through the second control line C2. In addition, the sensing unit 15 may sense the sensing current of only some of the pixels during the second sensing period, or sense the sensing current of all of the pixels according to the control signal provided from the timing controller 11, and output a second sensing value (or multiple second sensing values) as the sensing current value.

[0070] Here, the first sensing period and the second sensing period may not overlap. In addition, the first sensing period and the second sensing period may be sequentially arranged periods, and for example, the first sensing period may be a period before the second sensing period, or the first sensing period may be a period occurring after the second sensing period.

[0071] The compensator 16 may calculate a current compensation value for each of the pixels based on the sensed value of the sensing unit 15. For example, the compensator 16 may calculate the current compensation value based on a preset reference current value and a second sensed value output from the sensing unit 15, and generate an output grayscale value by reflecting the current compensation value to an input grayscale value input from the outside. As another example, the compensator 16 may calculate the current compensation value based on a preset reference voltage value and a first sensed value output from the sensing unit 15, and generate an output grayscale value by reflecting the current compensation value to an input grayscale value input from the outside.

[0072] Here, the reference current value (or reference current data) may be a digital value of a current flowing through a pixel, and may mean a current value expected when reference grayscale data is input from the outside, and the reference voltage value (or reference voltage data) may be a digital value of a voltage generated by a light emitting diode included in a pixel, and may mean a voltage value expected when reference grayscale data is input. The reference current value and the reference voltage value may be pre-stored in the memory 17 before shipment, and may be actively redefined during use of the product.

[0073] Meanwhile, the input grayscale value may be grayscale data input from an external processor and may mean grayscale data of an image frame. In addition, the output grayscale value may mean grayscale data input to the data driver 12 after compensating the input grayscale value by the compensator 16.

[0074] The compensator 16 may include a lookup table (not shown). The lookup table may exist in a data form, and may also exist in a physical form. Figure 1Before shipment of the display device 10, the lookup table may pre-store compensation amount data corresponding to the sensed value or the amount of change in the sensed value. A detailed description thereof will be described later. Meanwhile, the lookup table may be included outside the compensator 16, for example, in the memory 17. In another embodiment, the lookup table may also be stored in Figure 1 The compensation amount data corresponding to the sensed value or the amount of change in the sensed value is updated after shipment of the display device 10 .

[0075] The memory 17 can store reference current values, reference voltage values, etc. and can store the above-described lookup table. The memory 17 can communicate internally with the compensator 16 to provide the compensator 16 with reference current values, reference voltage values, compensation amount data of the lookup table, etc.

[0076] Hereinafter, a pixel according to an embodiment of the present disclosure is described, and for convenience, Figure 1 The pixel PXij shown in FIG. 8 is referred to as a first pixel PXij defined by the i-th first scan line S1i and the i-th second scan line S2i and the j-th data line Dj.

[0077] Figure 2 It is shown Figure 1 An equivalent circuit diagram of an embodiment of a first pixel PXij included in the display device 10 of FIG. Figure 3 It shows that in the display period Figure 2 A timing diagram of the operation of the first pixel PXij emitting light, and Figure 4 It shows that in the display period Figure 2 Equivalent circuit diagram of the operation of the first pixel PXij emitting light.

[0078] refer to Figure 2 , the first pixel PXij included in the display device 10 according to an embodiment of the present disclosure may include a first transistor T1, a second transistor T2, a third transistor T3, a storage capacitor Cst, and a light source unit LSU.

[0079] Transistors T1, T2 and T3 may be configured as N-type transistors. In another embodiment, transistors T1, T2 and T3 may be configured as P-type transistors. In another embodiment, transistors T1, T2 and T3 may be configured as a combination of N-type transistors and P-type transistors. N-type transistors generally refer to transistors in which the amount of on-current increases when the voltage difference between the gate electrode and the source electrode increases in the positive direction. P-type transistors generally refer to transistors in which the amount of on-current increases when the voltage difference between the gate electrode and the source electrode increases in the negative direction. Such transistors may be configured in various forms such as thin film transistors (TFTs), field effect transistors (FETs) and bipolar junction transistors (BJTs).

[0080] The first transistor T1 may include a gate electrode connected to the first node N1, a first electrode connected to the first power source ELVDD, and a second electrode connected to the second node N2. The first transistor T1 may be referred to as a driving transistor.

[0081] The second transistor T2 may include a gate electrode connected to a first scan line (e.g., an i-th first scan line S1i, hereinafter the same), a first electrode connected to a data line (e.g., a j-th data line Dj, hereinafter the same), and a second electrode connected to the first node N1. The second transistor T2 may be referred to as a scan transistor.

[0082] The third transistor T3 may include a gate electrode connected to a second scan line (e.g., the i-th second scan line S2i, the same hereinafter), a first electrode connected to a second node N2, and a second electrode connected to a sensing line (e.g., the j-th sensing line Ij, the same hereinafter).

[0083] The storage capacitor Cst may include a first electrode connected to the first node N1 and a second electrode connected to the second node N2 .

[0084] The light source unit LSU may include a plurality of light emitting diodes LD1 and LD2 electrically connected between a first power source ELVDD and a second power source ELVSS. Each of the light emitting diodes LD1 and LD2 may have a size ranging from nanometer level to micrometer level. However, the present disclosure is not limited thereto. In an embodiment, the light emitting diodes LD1 and LD2 may be connected to each other in a series structure. For example, the light source unit LSU may include a first light emitting diode LD1 and a second light emitting diode LD2, the first light emitting diode LD1 including a cathode and an anode connected to a second node N2, and the second light emitting diode LD2 including an anode connected in series with the cathode of the first light emitting diode LD1 and a cathode connected to the second power source ELVSS. However, the present disclosure is not limited thereto, and as will be referred to later Figures 13 to 16 As described, a plurality of light emitting diodes included in the light source unit LSU may be connected in a combination of a series structure and a parallel structure.

[0085] refer to Figure 3, during the display period, data voltages DV(i-1)j, DVij, and DV(i+1)j may be sequentially applied to the j-th data line Dj in units of horizontal periods. In addition, a scan signal of a conduction level (high level) may be applied to the i-th first scan line S1i in the corresponding horizontal period, and a scan signal of a cutoff level (low level) may be applied to the i-th second scan line S2i in synchronization with the i-th first scan line S1i. In another embodiment, during the display period, a scan signal of a cutoff level may be applied to the i-th second scan line S2i. At the same time, a control signal of a cutoff level may be applied to the first control line C1 and the second control line C2.

[0086] refer to Figure 3 and Figure 4 , for example, during the display period, a scan signal of a turn-on level is provided to the i-th first scan line S1i, and a scan signal of a turn-off level is provided to the i-th second scan line S2i, the second transistor T2 may be turned on, and the third transistor T3 may be turned off. In addition, the data voltage DVij may be provided to the j-th data line Dj at any time point (e.g., td) during which the turn-on state of the second transistor T2 is maintained. Therefore, a voltage corresponding to the difference between the data voltage DVij and the voltage of the second node N2 is written to the storage capacitor Cst of the first pixel PXij. At the same time, during the display period, since the control signal of the turn-off level is provided to the first control line C1 and the second control line C2, the sensing operation of the sensing unit 15 may be stopped.

[0087] refer to Figure 4 In the first pixel PXij, the driving current I flowing through the driving path between the first power source ELVDD, the first transistor T1 and the second power source ELVSS can be determined according to the voltage difference between the gate electrode and the source electrode (for example, the second electrode) of the first transistor T1. D amount, and can be based on the drive current I D The flow of generates a driving voltage V in the light source unit LSU D Therefore, the driving current I D The brightness of the light source unit LSU (specifically, the light emitting diodes LD1 and LD2) is determined by the amount.

[0088] Then, refer to Figure 3 and Figure 4, thereafter, when a scan signal of a turn-off level is applied to the i-th first scan line S1i and the i-th second scan line S2i, the second transistor T2 and the third transistor T3 may be turned off. Therefore, regardless of the voltage change of the j-th data line Dj, the voltage difference between the gate electrode and the source electrode of the first transistor T1 may be maintained by the storage capacitor Cst, and the brightness of the light source unit LSU (specifically, the light emitting diodes LD1 and LD2) may be maintained.

[0089] Figure 5 It is shown Figure 1 FIG. 1 is a diagram of a first pixel PXij, a sensing unit 15, a compensator 16, and a memory 17 included in a display device 10 of FIG.

[0090] refer to Figure 5 , the first pixel PXij may include the above reference Figure 2 The first transistor T1, the second transistor T2, the third transistor T3, the storage capacitor Cst, and the light source unit LSU are described, and their descriptions are omitted.

[0091] The sensing unit 15 may be connected to the first pixel PXij through the jth sensing line Ij. Specifically, the sensing unit 15 may be connected to the second electrode of the third transistor T3 included in the first pixel PXij through the jth sensing line Ij.

[0092] Meanwhile, in order to detect the driving voltage V generated by the light source unit LSU during light emission, D In order to detect whether the driving voltage V generated in the first light emitting diode LD1 and the second light emitting diode LD2 is in a normal state corresponding to the required brightness, the sensing unit 15 can output a sensing value by sensing the voltage of the second node N2 in the first sensing period. t> Whether normal or not, the sensing unit 15 may sense the voltage of the second node N2 during the first sensing period and output a voltage value of the voltage of the second node N2 as a first sensing value.

[0093] At the same time, in order to detect the driving current I flowing to the light source unit LSU D In order to detect whether the driving current I flowing through the first light emitting diode LD1 and the second light emitting diode LD2 is in a stable state corresponding to the desired brightness, the sensing unit 15 can output a sensing value by sensing the current flowing to the second node N2 in the second sensing period. D Whether normal, the sensing unit 15 may sense a sensing current as a current flowing through the second node N2 during a second sensing period not overlapping the first sensing period, and output a current value of the sensing current as a second sensing value.

[0094] As an embodiment, the compensator 16 may receive a first sensing value during a first sensing period, and calculate a current compensation value for the first pixel PXij based on the first sensing value. In this case, since the first sensing value is a voltage value of the voltage of the second node N2, when the voltage of the second node N2 decreases, the compensator 16 may increase the current compensation value to maintain the desired brightness. At this time, the compensator 16 may communicate internally with the memory 17 to receive a lookup table, a reference voltage value, etc. required to calculate the current compensation value.

[0095] As another embodiment, the compensator 16 may receive a second sensing value during a second sensing period, and calculate a current compensation value for the first pixel PXij based on the second sensing value. In this case, the second sensing value may be a current controlled by the first transistor T1, and such a current may include information about characteristics such as a threshold voltage and mobility in the first transistor T1 even in the transistor. Therefore, when information about the characteristics of the first transistor T1 is obtained from the second sensing value, the compensator 16 may calculate a current compensation value for each of the pixels in order to minimize the brightness deviation occurring between the pixels.

[0096] The compensator 16 may provide the current compensation value to the timing controller 11. The timing controller 11 may provide the compensated grayscale value (not shown) to the data driver 12 by reflecting the current compensation value to the grayscale value of the image frame from the external processor. The data driver 12 may generate a compensated data voltage (not shown) to be provided to the j-th data line Dj by using the compensated grayscale value. The above-described embodiments may be applied to Figure 1 Each of the pixels included in the display device 10.

[0097] Hereinafter, an embodiment of the sensing unit 15 is described in detail.

[0098] Figure 6 It is shown Figure 5 1 is an equivalent circuit diagram of an embodiment of the sensing unit 15 .

[0099] refer to Figure 6 The sensing unit 15 may include a first sensing transistor Ts1, a second sensing transistor Ts2, a third sensing transistor Ts3, a fourth sensing transistor Ts4, a first resistor R1, a second resistor R2, a third resistor R3, an amplifier AMP, an analog-to-digital converter ADC, and the like.

[0100] The first sensing transistor Ts1 may include a gate electrode connected to the first control line C1 , a first electrode connected to the j-th sensing line Ij, and a second electrode connected to the third node N3 .

[0101] The second sensing transistor Ts2 may include a gate electrode connected to the second control line C2 , a first electrode connected to the reference power source Rvdd, and a second electrode connected to the third node N3 .

[0102] The third sensing transistor Ts3 may include a gate electrode connected to the second control line C2 , a first electrode connected to the j-th sensing line Ij, and a second electrode connected to the fourth node N4 .

[0103] The first resistor R1 may include a first terminal connected to the fourth node N4 and a second terminal connected to the fifth node N5 . A resistance value of the first resistor R1 may be a value designed by a designer and may be stored in the memory 17 .

[0104] The fourth sensing transistor Ts4 may include a gate electrode connected to the first control line C1 , a first electrode connected to the reference power source Rvdd, and a second electrode connected to the fifth node N5 .

[0105] The second resistor R2 may include a first terminal connected to the fifth node N5 and a second terminal connected to the sixth node N6. A resistance value of the second resistor R2 may be a value designed by a designer and may be stored in the memory 17.

[0106] The amplifier AMP may include a first input terminal (eg, a non-inverting terminal) connected to the third node N3, a second input terminal (eg, an inverting terminal) connected to the sixth node N6, and an output terminal connected to the analog-to-digital converter ADC and the third resistor R3. The amplifier AMP may be configured as an operational amplifier.

[0107] As an embodiment, the amplifier AMP may output an output voltage Vout through an output terminal, the output voltage Vout being amplified according to a preset gain based on a difference between a voltage input to the first input terminal and a voltage input to the second input terminal.

[0108] The third resistor R3 may include an output terminal (specifically, a second terminal connected to the seventh node N7) and a first terminal connected to the sixth node N6. The resistance value of the third resistor R3 may be a value designed by a designer and may be stored in the memory 17.

[0109] At the same time, the voltage input to the first input terminal of the amplifier AMP and the voltage input to the second input terminal of the amplifier AMP may be equipotential according to the virtual short circuit, and the current flowing to each of the first input terminal and the second input terminal may not exist. Therefore, when the voltage of the preset reference power supply Rvdd is applied to any one of the third node N3 and the fifth node N5, an unknown voltage is applied to the other node and thus the output voltage Vout of the amplifier AMP is output, the unknown voltage can be calculated based on the voltage of the reference power supply Rvdd, the output voltage Vout of the amplifier AMP, the resistance value of the second resistor R2, and the resistance value of the third resistor R3. At the same time, when the voltage of the preset reference power supply Rvdd is applied to the third node N3, an unknown current flows to the first resistor R1 and thus the output voltage Vout of the amplifier AMP is output, the unknown current can also be calculated based on the voltage of the reference power supply Rvdd, the output voltage Vout of the amplifier AMP, the resistance value of the second resistor R2, and the resistance value of the third resistor R3. Refer to later Fig. 9 and Fig.12 To describe its detailed description.

[0110] The analog-to-digital converter ADC may be connected to the output terminal of the amplifier AMP. The analog-to-digital converter ADC may convert an analog signal into a digital value. Specifically, the analog-to-digital converter ADC may receive an output voltage Vout as an analog signal and convert the output voltage Vout into an output voltage value as a digital value. The converted output voltage value may be provided to Figure 5 The compensator 16 shown in FIG.

[0111] Hereinafter, a voltage sensing operation of the sensing unit 15 is described.

[0112] Figure 7 is a diagram showing that in the first sensing period Figure 5 A timing diagram of the operation of the sensing unit 15 sensing the voltage, Figure 8 is an exemplary illustration of the first sensing period. Figure 5 An equivalent circuit diagram of the voltage and current generated in the first pixel PXii, and Fig. 9 is a diagram showing that in the first sensing period Figure 6 1 is an equivalent circuit diagram of an operation of the sensing unit 15 sensing the voltage of the second node N2.

[0113] refer to Figure 7During the first sensing period, the first sensing data voltages SDV1(i-1)j, SDV1ij, and SDV1(i+1)j may be sequentially applied to the j-th data line Dj in units of horizontal periods. At the same time, a scan signal of an on level may be applied to the i-th first scan line S1i in the corresponding horizontal period. In addition, in synchronization with the i-th first scan line S1i, a scan signal of an on level may be applied to the i-th second scan line S2i. At the same time, a control signal of an on level may be applied to the first control line C1, and a control signal of an off level may be applied to the second control line C2.

[0114] refer to Figure 7 and Figure 8 For example, during the first sensing period, when a scan signal of a turn-on level is provided to each of the i-th first scan line S1i and the i-th second scan line S2i, the second transistor T2 and the third transistor T3 may be turned on. The first sensing data voltage SDV1ij may be provided to the j-th data line Dj at any time point (e.g., tss1) during which the turn-on state of the second transistor T2 is maintained. A voltage corresponding to a difference between the first sensing data voltage SDV1ij and an initial power source (not shown) applied to the second node N2 is written to the storage capacitor Cst of the first pixel PXij. In addition, in the first pixel PXij, according to a voltage difference between a gate electrode and a source electrode (e.g., a second electrode) of the first transistor T1, a current I may flow through a path between the first power source ELVDD, the first transistor T1, and the second power source ELVSS, and when the current I flows, a voltage V may be generated in the light source unit LSU. Here, the voltage of the second node N2 may correspond to the sum of the voltage of the second power source ELVSS and the voltage V generated in the light source unit LSU. At this time, since the third transistor T3 is turned on, the voltage of the second node N2 can be provided to the j-th sensing line Ij.

[0115] refer to Figures 7 to 9, during the first sensing period, when a control signal of a turn-on level is provided to the first control line C1 and a control signal of a turn-off level is provided to the second control line C2, the first sensing transistor Ts1 and the fourth sensing transistor Ts4 may be turned on, and the second sensing transistor Ts2 and the third sensing transistor Ts3 may be turned off. At this time, the voltage of the second node N2 may be applied to the third node N3 through the j-th sensing line Ij, and the voltage of the reference power supply Rvdd may be applied to the fifth node N5. In this case, the amplifier AMP may output a first output voltage based on the voltage of the third node N3 and the voltage of the reference power supply Rvdd, the output first output voltage may be input to the analog-to-digital converter ADC, and the first output voltage value of the first output voltage may be provided to the compensator 16. The compensator 16 may obtain a voltage value (first sensing value) of the voltage of the second node N2 from the first output voltage value of the first output voltage.

[0116] Specifically, for example, the voltage of the third node N3 applied to the first input terminal of the amplifier AMP and the voltage applied to the second input terminal of the amplifier AMP (i.e., the voltage of the sixth node N6) may be equipotential, and the current flowing through the second resistor R2 and the current flowing through the third resistor R3 are the same. This can be expressed as the following [Equation 1].

[0117] [Equation 1]

[0118]

[0119] Here, V ref Refers to the voltage of the reference power supply Rvdd, V vs It means the voltage of the third node N3, V out1 means the first output voltage, R2 means the resistance value of the second resistor R2, and R 3 It means the resistance value of the third resistor R3.

[0120] Here, the voltage of the third node N3 may be expressed as the following [Equation 2] by generalizing the terms of [Equation 1].

[0121] [Equation 2]

[0122]

[0123] Here, since the digital value of the voltage of the reference power supply Rvdd, the resistance value of the second resistor R2, and the resistance value of the third resistor R3 can be pre-stored in the memory 17, and the first output voltage value as the digital value of the first output voltage is output by the analog-to-digital converter ADC, the compensator 16 can calculate the voltage value of the voltage of the third node N3 by substituting the digital value of the voltage of the reference power supply Rvdd, the resistance value of the second resistor R2, the resistance value of the third resistor R3, and the first output voltage value into the above-described [Equation 2]. Therefore, the voltage of the second node N2 corresponding to the voltage of the third node N3 can be measured.

[0124] When the second resistor R2 and the third resistor R3 are the same, the voltage of the third node N3 may be expressed as the following [Equation 3].

[0125] [Equation 3]

[0126]

[0127] At the same time, the compensator 16 can calculate the change amount of the voltage of the second node N2 based on the preset reference voltage value and the first output voltage value of the first output voltage. Here, the reference voltage value can be stored in the above reference voltage value. Figure 1 Specifically, the compensator 16 can use the above-described [Equation 2] (when the second resistor R2 and the third resistor R3 are the same, use [Equation 3]) to calculate the voltage value (first sensing value) of the voltage of the second node N2 corresponding to the voltage of the third node N3, receive the reference voltage value from the memory 17, and calculate the difference between the reference voltage value and the voltage value of the voltage of the second node N2, the reduction ratio of the voltage value of the second node N2 compared to the reference voltage value, etc., to calculate the change amount of the voltage of the second node N2. At this time, the compensator 16 can increase the current compensation value as the change amount increases.

[0128] Here, as an implementation method for calculating the current compensation value of the second node N2, the compensator 16 can calculate the reduction ratio of the ratio of the sensing value of the voltage of the second node N2 (for example, the first sensing value) to the reference voltage value (that is, the first sensing value / reference voltage value), extract the compensation amount data corresponding to the reduction ratio data from a pre-stored lookup table, and calculate the current compensation value based on the extracted compensation amount data.

[0129] According to the above embodiment, there is a Figure 1 The display device 10 has the effect of improving the operation speed by calculating the current compensation value using a set lookup table before shipment.

[0130] As another embodiment of calculating the current compensation value of the second node N2, the compensator 16 may increase the current compensation value in inverse proportion to the amount of decrease in the voltage of the second node N2, so that the power consumption in the light source unit LSU is always constant. Specifically, the compensator 16 may calculate the current compensation value based on the ratio of the reference voltage value to the sensed value (e.g., the first sensed value) of the voltage of the second node N2 (i.e., the reference voltage value / the first sensed value). For example, when the ratio of the first sensed value to the reference voltage value is 2 / 3, since the ratio of the reference voltage value to the first sensed value (which corresponds to the inverse of the above ratio) is 3 / 2 (i.e., 1.5), the compensator 16 may calculate the current compensation value as the driving current I of the first pixel PXij. D 1.5 times of.

[0131] As described above, the compensator 16 may provide the current compensation value to the timing controller 11, and the timing controller 11 may provide the compensated grayscale value (not shown) to the data driver 12 by reflecting the current compensation value to the grayscale value of the image frame from the external processor. The data driver 12 may generate a compensated data voltage (not shown) to be provided to the j-th data line Dj by using the compensated grayscale value. The above-described embodiments may be applied to Figure 1 Each of the pixels included in the display device 10.

[0132] According to an embodiment, when a first current compensation value for a first pixel PXij and a second current compensation value for a second pixel (not shown) are different from each other, the data driver 12 may provide different data voltages to the first pixel PXij and the second pixel even if the timing controller 11 receives the same grayscale value for the first pixel PXij and the second pixel from an external processor.

[0133] For example, when the first current compensation value is greater than the second current compensation value, the data driver 12 may provide a data voltage greater than a data voltage of the second pixel to the first pixel PXij to allow a larger driving current to flow through the first pixel PXij.

[0134] However, with Figure 2 Unlike shown in , when the first transistor T1 of the pixel is configured as a P-type transistor, the data driver 12 can provide a data voltage smaller than the data voltage of the second pixel to the first pixel PXij to allow a larger driving current to flow through the first pixel PXij.

[0135] According to the above-described embodiment, there is an effect of improving accuracy by calculating the current compensation value in real time according to the voltage of the second node N2 sensed after shipment.

[0136] Hereinafter, a current sensing operation of the sensing unit 15 is described.

[0137] Fig.10 is a diagram showing that in the second sensing period Figure 5 A timing diagram of the operation of the sensing unit 15 sensing current, Fig.11 is an exemplary illustration of the second sensing period. Figure 5 An equivalent circuit diagram of the voltage and current generated in the first pixel PXij, and Fig.12 is a diagram showing that in the second sensing period Figure 6 1 is an equivalent circuit diagram of an operation of the sensing unit 15 sensing the current of the first pixel PXij.

[0138] refer to Fig.10 , during the second sensing period, the second sensing data voltages SDV2(i-1)j, SDV2ij, and SDV2(i+1)j may be sequentially applied to the j-th data line Dj in units of horizontal periods. Here, the second sensing data voltages SDV2(i-1)j, SDV2ij, and SDV2(i+1)j may be the same as or different from the first sensing data voltages SDV1(i-1)j, SDV1ij, and SDV1(i+1)j. At the same time, a scan signal of a conduction level may be applied to the i-th first scan line S1i in the corresponding horizontal period. In addition, in synchronization with the i-th first scan line S1i, a scan signal of a conduction level may also be applied to the i-th second scan line S2i. In addition, the voltage of the second power supply ELVSS may be maintained in a state in which the voltage of the second power supply ELVSS increases from a first level to a second level. Here, when the first level is, for example, a low level, the second level may be a high level. Meanwhile, a control signal of an off level may be applied to the first control line C1 , and a control signal of an on level may be applied to the second control line C2 .

[0139] refer to Fig.10 and Fig.11 , for example, during the second sensing period, when a scan signal of a turn-on level is provided to each of the i-th first scan line S1i and the i-th second scan line S2i, the second transistor T2 and the third transistor T3 may be turned on. The second sensing data voltage SDV2ij may be provided to the j-th data line Dj at any time point (e.g., tss2) during which the turn-on state of the second transistor T2 is maintained. A voltage corresponding to the difference between the second sensing data voltage SDV2ij and an initial power source (not shown) applied to the second node N2 is written to the storage capacitor Cst of the first pixel PXij. In addition, in the first pixel PXij, the sensing current I is determined according to the voltage difference between the gate electrode and the source electrode of the first transistor T1. S At this time, since the third transistor T3 is turned on, the sensing current Is can be provided to the sensing unit 15 through the j-th sensing line Ij.

[0140] refer to Figures 10 to 12 , during the second sensing period, when a control signal of a cut-off level is provided to the first control line C1 and a control signal of a turn-on level is provided to the second control line C2, the first sensing transistor Ts1 and the fourth sensing transistor Ts4 may be turned off, and the second sensing transistor Ts2 and the third sensing transistor Ts3 may be turned on. At this time, the sensing current Is may flow to the first resistor R1 through the j-th sensing line Ij and the third sensing transistor Ts3, and a voltage of the fifth node N5 may be generated according to the flow of the sensing current Is. In addition, a voltage of a reference power supply Rvdd may be applied to the third node N3. In this case, the amplifier AMP may output a second output voltage based on the voltage of the fifth node N5 and the voltage of the reference power supply Rvdd, the output second output voltage may be input to the analog-to-digital converter ADC, and thus a second output voltage value of the second output voltage may be provided to the compensator 16. The compensator 16 may obtain a current value of the sensing current Is from the second output voltage value of the second output voltage.

[0141] Specifically, for example, similar to the description, the voltage of the reference power supply Rvdd applied to the first input terminal of the amplifier AMP and the voltage applied to the second input terminal of the amplifier AMP (i.e., the voltage of the sixth node N6) may be equipotential, and the sensing current Is flowing through the first resistor R1, the current flowing through the second resistor R2, and the current flowing through the third resistor R3 are the same. This can be expressed as the following [Equation 4].

[0142] [Equation 4]

[0143]

[0144] Here, I s Means the sense current, V ref Refers to the voltage of the reference power supply Rvdd, V is It means the voltage of the fifth node N5, V out2 means the second output voltage, R 2 means the resistance value of the second resistor R2, and R 3 It means the resistance value of the third resistor R3.

[0145] Here, since the digital value of the voltage of the reference power supply Rvdd, the resistance value of the second resistor R2, and the resistance value of the third resistor R3 are pre-stored in the memory 17, and the second output voltage value as the digital value of the second output voltage is output by the analog-to-digital converter ADC, the compensator 16 can calculate the current value of the sensing current Is by substituting the digital value of the voltage of the reference power supply Rvdd, the resistance value of the second resistor R2, the resistance value of the third resistor R3, and the second output voltage value into the above-described [Equation 4]. Therefore, the sensing current Is can be measured.

[0146] Meanwhile, the compensator 16 may calculate the sensing current I based on the preset reference current value and the second output voltage value of the second output voltage. s Specifically, the compensator 16 can use the above-mentioned [Equation 4] to calculate the sensing current I s The current value (second sensing value) of the sensor 1 is received from the memory 17, and the reference current value and the sensing current I are calculated. S The difference between the current values, the sensing current I S The current value is compared to the reference current value by the reduction ratio, etc., to calculate the sensing current I s In addition, the change in the sensing current I s The current compensation value is calculated based on the change in

[0147] According to the above-described embodiment, since the operation of sensing the voltage and current applied to the light emitting diode is implemented with a relatively simple circuit structure, there is an effect that manufacturing terminals can be reduced.

[0148] Furthermore, according to the above-described embodiments, a more integrated display device 10 may be provided by implementing a circuit structure capable of sensing a voltage and a current applied to a light emitting diode.

[0149] Fig.13 is a diagram exemplarily showing a light source unit LSU of the present disclosure, Fig.14 is an exemplary illustration of the application to Fig.13 A diagram of the voltage and current of the light source unit LSU, and Fig.15 and 16 is a graph exemplarily showing a change in the magnitude of each of a voltage and a current applied to the light source unit LSU when a light emitting diode is short-circuited.

[0150] refer to Fig.13 , Fig.13 The light source unit LSU shown in FIG. 1 may include Figure 2 , Figure 4 , Figure 5 , Figure 8 and Fig.11 The light source unit LSU shown in FIG. 1 comprises three or more different light emitting diodes.

[0151] Here, included Fig.13The light emitting diodes in the light source unit LSU shown in the figure can be connected in a combination of a series structure and a parallel structure, and can include a light emitting diode unit in which one or more light emitting diodes are grouped. For example, the light source unit LSU may include a first light emitting diode unit LDU1, a second light emitting diode unit LDU2, and a third light emitting diode unit LDU3, and the number of light emitting diodes included in each of the first light emitting diode unit LDU1, the second light emitting diode unit LDU2, and the third light emitting diode unit LDU3 may be the same as or different from each other. However, the present disclosure is not limited to this. Hereinafter, for convenience, the embodiments of the present disclosure are described based on each of the first light emitting diode unit LDU1, the second light emitting diode unit LDU2, and the third light emitting diode unit LDU3 including the same number of light emitting diodes.

[0152] A light emitting diode unit may mean a group of light emitting diodes connected only in a parallel structure. In addition, one light emitting diode unit and another light emitting diode unit may be connected to each other in a series structure. For example, a first light emitting diode unit LDU1, a second light emitting diode unit LDU2, and a third light emitting diode unit LDU3 may be connected to each other in a series structure.

[0153] At the same time, since the connection structure between the light emitting diode units is a series structure, the current flowing through each of the light emitting diode units can be the same. At the same time, since the connection structure between the plurality of light emitting diodes included in any one light emitting diode unit is a parallel structure, the voltage generated in one light emitting diode unit and the voltage generated in each of the plurality of light emitting diodes included in one light emitting diode unit can be the same.

[0154] refer to Fig.14 For example, when the first drive current I D1 When the first driving current I flows through the light source unit LSU according to the required brightness in the first pixel PXij, D1 may flow through each of the first light emitting diode unit LDU1, the second light emitting diode unit LDU2, and the third light emitting diode unit LDU3. In addition, when the first driving voltage V is generated in the light source unit LSU D1 When the first driving voltage V D1 The voltage generated in each of the first light emitting diode unit LDU1, the second light emitting diode unit LDU2 and the third light emitting diode unit LDU3 may be the first driving voltage V D1 1 / 3 of.

[0155] Meanwhile, when at least one of the light emitting diodes included in one light emitting diode unit is short-circuited, the one light emitting diode unit does not emit light. In this case, since the voltage generated in the light source unit LSU is reduced, when the driving current is not compensated, the light source unit LSU may not emit light with a desired brightness. Therefore, as described above, the display device 10 according to an embodiment of the present disclosure can compensate for the driving current by sensing the voltage generated in the light source unit LSU.

[0156] refer to Fig.15 For example, when at least one light emitting diode included in the second light emitting diode unit LDU2 is short-circuited, the second light emitting diode unit LDU2 does not emit light. At this time, the voltage generated in the light source unit LSU can be increased from the first driving voltage V D1 Change to the second driving voltage V D2 Here, the second driving voltage V D2 can be less than the first driving voltage V D1 In this case, the display device 10 according to the embodiment of the present disclosure may sense the second driving voltage V D2 , calculating the current compensation value by calculating the change amount of the driving voltage, and increasing the first driving current I for the first pixel PXij by providing the compensation data voltage according to the compensated grayscale value D1 , thereby maintaining the power consumption of the light source unit LSU. In this case, since the first driving current I D1 The second driving current I D2 exist Fig.15 Flows in the light source unit LSU shown in , so the light source unit LSU can emit light with the required brightness in the first pixel PXij.

[0157] Specifically, for example, the display device 10 according to the embodiment of the present disclosure calculates the first driving voltage V D1 and the second driving voltage V D2 The first ratio of the first driving current I is calculated, and the inverse of the first ratio is the first driving current I D1 The display device 10 generates a compensated grayscale value by reflecting the calculated current compensation value to the received grayscale value, and sends the current compensation value to the display device 10 including Fig.15 The first pixel PXij of the light source unit LSU shown in FIG. 1 provides a compensated data voltage according to the compensated grayscale value. The second driving current I D2 Can be Fig.15 , and at this time, the second driving current I D2 Can be connected with the first driving current I D1 The same as the product of the reciprocal of the first ratio.

[0158] In other words, since the voltage generated in each of the first light emitting diode unit LDU1, the second light emitting diode unit LDU2, and the third light emitting diode unit LDU3 is the first driving voltage V D1 Therefore, when the second light emitting diode unit LDU2 does not emit light, the second driving voltage V D2 It can be the first driving voltage V D1 Therefore, the first ratio may be 2 / 3, and the second drive current I D2 It can be the first driving current I D1 1.5 times of.

[0159] At the same time, reference Fig.16 For example, when at least one light emitting diode included in the third light emitting diode unit LDU3 is further short-circuited, the second light emitting diode unit LDU2 and the third light emitting diode unit LDU3 do not emit light. At this time, the voltage generated in the light source unit LSU can be increased from the second driving voltage V D2 Change to the third driving voltage V D3 Here, the third driving voltage V D3 can be less than the second driving voltage V D2 Likewise, in this case, similar to the above description, the display device 10 according to the embodiment of the present disclosure may sense the third driving voltage V D3 , calculating the current compensation value by calculating the change amount of the driving current, and increasing the second driving current I for the first pixel PXij by providing the compensation data voltage according to the compensated grayscale value to the first pixel PXij D2 , thereby maintaining the power consumption of the light source unit LSU. In this case, since the second driving current I D2 The third driving current I D3 exist Fig.16 Flows in the light source unit LSU shown in , so the light source unit LSU can continuously emit light with the required brightness in the first pixel PXij.

[0160] Specifically, for example, the display device 10 according to the embodiment of the present disclosure may calculate the first driving voltage V D1 and the third driving voltage V D3 The second ratio of the first driving current I is calculated, and the inverse of the second ratio is calculated. D1 The display device 10 generates a compensated grayscale value by reflecting the calculated current compensation value to the received grayscale value, and sends the current compensation value to the display device 10 including Fig.16 The first pixel PXij of the light source unit LSU shown in FIG. 1 provides a compensated data voltage according to the compensated grayscale value. The third driving current ID3 Can be Fig.16 , and at this time, the third driving current I D3 Can be connected with the first driving current I D1 The same as the product of the reciprocal of the second ratio.

[0161] In other words, since the voltage generated in each of the first light emitting diode unit LDU1, the second light emitting diode unit LDU2, and the third light emitting diode unit LDU3 is the first driving voltage V D1 Therefore, when the second light emitting diode unit LDU2 and the third light emitting diode unit LDU3 do not emit light, the third driving voltage V D3 It can be the first driving voltage V D1 At this time, the second ratio may be 1 / 3, and the third driving current I D3 It can be the first driving current I D1 Three times.

[0162] As shown by way of example Figures 14 to 16 The light source unit shown in the figure is used to describe the embodiments of the present disclosure, so the number of light emitting diode units, the number of light emitting diodes, etc. are not limited to Figures 14 to 16 Those shown in .

[0163] According to the above, the display device 10 according to the embodiment of the present disclosure can minimize the brightness deviation by calculating the current compensation value so that even if the light emitting diode is short-circuited, the corresponding pixel emits light with the required brightness.

[0164] Furthermore, according to the above-described contents, the display device 10 according to the embodiment of the present disclosure can extend the life of a product by maintaining the required brightness for each of the pixels.

[0165] Hereinafter, a method of driving the display device 10 according to an embodiment of the present disclosure is described in detail.

[0166] Fig.17 is a flowchart illustrating a method of driving the display device 10 according to an embodiment.

[0167] refer to Fig.17 , the method of driving the display device 10 according to an embodiment of the present disclosure may be a method of detecting a short-circuited defective light emitting diode among a plurality of light emitting diodes included in a pixel and calculating a current compensation value when the defective light emitting diode is detected.

[0168] Such a driving method may include a voltage sensing step S110 , a defective light emitting diode detecting step S120 , a current compensation value calculating step S130 , and the like.

[0169] The voltage sensing step S110 corresponds to a step of sensing a voltage applied to a plurality of light emitting diodes included in a pixel.

[0170] Here, the pixel may include a first transistor T1, a first light emitting diode LD1, and a second light emitting diode LD2, the first transistor T1 including a gate electrode connected to the first node N1, a first electrode connected to the first power source ELVDD, and a second electrode connected to the second node N2, the first light emitting diode LD1 including a cathode and an anode connected to the second node N2, and the second light emitting diode LD2 including an anode connected in series with the cathode of the first light emitting diode LD1 and a cathode connected to the second power source ELVSS. At this time, the voltage sensing step S110 senses the voltage of the second node N2.

[0171] The defective light emitting diode detecting step S120 corresponds to a step of detecting whether a defective light emitting diode pixel short-circuited exists in the pixel based on the voltage of the second node N2 and a preset reference voltage.

[0172] Here, when the voltage of the second node N2 is less than the reference voltage, the defective light emitting diode detecting step S120 may determine that a defective light emitting diode exists.

[0173] The current compensation value calculation step S130 corresponds to a step of calculating a current compensation value for a pixel when a defective light emitting diode is detected and increasing the current compensation value as the voltage decreases.

[0174] Here, the current compensation value calculation step S130 calculates a variation amount of the voltage of the second node N2 based on the voltage of the second node N2 and a reference voltage, and increases the current compensation value as the variation amount increases.

[0175] As described above, embodiments of the present disclosure may provide a display device and a method of driving the display device, which minimizes brightness deviation between pixels by allowing corresponding pixels to emit light with appropriate brightness even if a light emitting diode is short-circuited.

[0176] Although the embodiments of the present disclosure have been described with reference to the accompanying drawings, it will be understood by those skilled in the art that these embodiments may be implemented in other specific forms without changing the technical spirit and basic features of the present disclosure. Therefore, it should be understood that the embodiments described above are illustrative and not restrictive in all aspects.

Claims

1. A display device, comprising: Pixels; A sensing unit connected to the pixel through a sensing line; as well as a compensator configured to calculate a current compensation value for each of the pixels based on the sensed value of the sensing unit, Wherein, the first pixel among the pixels comprises: a first transistor including a gate electrode connected to a first node, a first electrode connected to a first power source, and a second electrode connected to a second node; a first light emitting diode including a cathode and an anode connected to the second node; and a second light emitting diode including an anode connected in series to the cathode of the first light emitting diode and a cathode connected to a second power source, wherein the sensing unit outputs a first sensing value by sensing a voltage of the second node during a first sensing period, and outputs a second sensing value by sensing a sensing current as a current flowing through the second node during a second sensing period that does not overlap with the first sensing period, and The compensator increases the current compensation value for the first pixel as the voltage of the second node decreases during the first sensing period, and receives the second sensing value during the second sensing period to calculate the current compensation value.

2. The display device according to claim 1, wherein: The first pixel further includes: a second transistor including a gate electrode connected to the first scan line, a first electrode connected to the data line, and a second electrode connected to the first node; and The third transistor includes a gate electrode connected to the second scan line, a first electrode connected to the second node, and a second electrode connected to the sensing line.

3. The display device according to claim 2, wherein: supplying a scanning signal of an on level to the first scanning line during a display period, supplying a scan signal of an off level to the second scan line during the display period, and A data voltage is supplied to the data line during the display period.

4. The display device according to claim 2, wherein: supplying a scan signal of an on level to the first scan line during the first sensing period, supplying the scan signal of the on level to the second scan line during the first sensing period, and A sensing data voltage is provided to the data line during the first sensing period.

5. The display device according to claim 2, wherein: supplying a scan signal of an on level to the first scan line during the second sensing period, supplying the scan signal of the on level to the second scan line during the second sensing period, providing a sensing data voltage to the data line during the second sensing period, and The voltage of the second power source is maintained in a state in which the voltage of the second power source increases from a first level to a second level.

6. The display device according to claim 1, wherein: The sensing unit comprises: a first sensing transistor including a gate electrode connected to the first control line, a first electrode connected to the sensing line, and a second electrode connected to a third node; a second sensing transistor including a gate electrode connected to the second control line, a first electrode connected to a reference power source, and a second electrode connected to the third node; a third sensing transistor including a gate electrode connected to the second control line, a first electrode connected to the sensing line, and a second electrode connected to a fourth node; a first resistor including a first terminal connected to the fourth node and a second terminal connected to a fifth node; a fourth sensing transistor including a gate electrode connected to the first control line, a first electrode connected to the reference power source, and a second electrode connected to the fifth node; a second resistor including a first terminal connected to the fifth node and a second terminal connected to a sixth node; an amplifier including an output terminal, a first input terminal connected to the third node, and a second input terminal connected to the sixth node; and A third resistor includes a first terminal connected to the sixth node and a second terminal connected to the output terminal.

7. The display device according to claim 6, wherein: providing a control signal of an on level to the first control line during the first sensing period, and A control signal of an off level is supplied to the second control line during the first sensing period.

8. The display device according to claim 7, wherein: The amplifier outputs a first output voltage based on a voltage of the third node and a voltage of the reference power supply.

9. The display device according to claim 8, wherein: The compensator calculates a variation of the voltage of the second node based on a first output voltage value of the first output voltage and a preset reference voltage value, and increases the current compensation value as the variation increases.

10. The display device according to claim 9, wherein: The compensator calculates a reduction ratio of the ratio of the sensed value of the voltage of the second node to the reference voltage value, extracts compensation amount data corresponding to the reduction ratio data from a pre-stored lookup table, and calculates the current compensation value from the extracted compensation amount data.

11. The display device according to claim 9, wherein: The compensator calculates the current compensation value based on a ratio of the reference voltage value and the sensed value of the voltage of the second node.

12. The display device according to claim 6, wherein: providing a control signal of an off level to the first control line during the second sensing period, and A control signal of an on level is provided to the second control line during the second sensing period.

13. The display device according to claim 12, wherein: The amplifier outputs a second output voltage based on the voltage of the fifth node and the voltage of the reference power supply.

14. The display device according to claim 13, wherein: The compensator calculates a variation amount of a sensed current as a current flowing through the second node based on a second output voltage value of the second output voltage and a preset reference current value, and calculates the current compensation value based on the variation amount.

15. A method for driving a display device according to any one of claims 1 to 14, the method comprising: a voltage sensing step of sensing a voltage applied to a plurality of light emitting diodes included in a pixel; A detection step of detecting whether there is a short-circuited defective light emitting diode in the pixel based on the voltage and a preset reference voltage; as well as A current compensation value calculation step of calculating a current compensation value for the pixel when the defective light emitting diode is detected and increasing the current compensation value as the voltage decreases.

16. The method according to claim 15, wherein: The pixels include: a first transistor including a gate electrode connected to a first node, a first electrode connected to a first power source, and a second electrode connected to a second node; a first light emitting diode including a cathode and an anode connected to the second node; and a second light emitting diode including an anode connected in series to the cathode of the first light emitting diode and a cathode connected to a second power source, and The voltage sensing step senses a voltage of the second node.

17. The method according to claim 16, wherein: When the voltage of the second node is less than the reference voltage, the defective light emitting diode detecting step determines that the defective light emitting diode exists.

18. The method according to claim 17, wherein: The current compensation value calculation step calculates a change amount of the voltage of the second node based on the voltage of the second node and the reference voltage, and increases the current compensation value as the change amount increases.

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