Display device

Abstract

To provide a display device that can reduce the time of sensing operation without deteriorating the accuracy of luminance compensation.SOLUTION: A display device includes: a pixel array having a plurality of pixels each including a plurality of sub-pixels, and a gate line shared by the plurality of sub-pixels; a gate driving portion supplying a gate signal to the plurality of sub-pixels through the gate line; a data driving portion supplying a data signal to each of the plurality of sub-pixels through a data line; a control portion selecting any sub-pixel from the plurality of sub-pixels included in the pixel on the basis of deterioration information of the sub-pixels and supplying the data signal from the data driving portion to the selected sub-pixel; and a compensation portion acquiring a property of the selected sub-pixel.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a display device.

Background Art

[0002] A display device such as an organic EL display periodically senses characteristic values of pixels in order to compensate for fluctuations in luminance caused by deterioration of pixels or the like.

[0003] Patent Document 1 discloses a display device that senses characteristic values of drive transistors from each of sub-pixels within each pixel that shares a gate line and a reference line.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When a gate line and a reference line are shared by sub-pixels, the sub-pixels cannot be sensed simultaneously. Therefore, a long sensing operation may be required to compensate for luminance between sub-pixels.

[0006] The present invention has been made in view of the above-described problems, and an object thereof is to provide a display device capable of shortening the time of a sensing operation without degrading the accuracy of luminance compensation.

Means for Solving the Problems

[0007] According to one aspect of the present invention, there is provided a display device including: a pixel array having a plurality of pixels each including a plurality of sub-pixels and a gate line shared by the plurality of sub-pixels; a gate driving unit configured to supply a gate signal to the plurality of sub-pixels via the gate line; a data driving unit configured to supply a data signal to each of the plurality of sub-pixels via a data line; a control unit configured to select any one of the plurality of sub-pixels included in the pixel based on deterioration information of the sub-pixels and supply the data signal from the data driving unit to the selected sub-pixel; and a compensation unit configured to acquire characteristics of the selected sub-pixel.

Effects of the Invention

[0008] According to the present invention, it is possible to shorten the time of the sensing operation without degrading the accuracy of luminance compensation between sub-pixels.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Elements having the same functions throughout the drawings are denoted by the same reference numerals, and redundant descriptions may be omitted or simplified.

[0011] [First Embodiment] FIG. 1 is a block diagram showing a schematic configuration of a display device 10 in the present embodiment. The display device 10 includes a control unit 11, a data driving unit 12, a gate driving unit 13, a compensation unit 14, and a display panel 15.

[0012] The control unit 11 receives a data signal DATA from a video processing unit (not shown). Further, the control unit 11 receives a data enable signal, a vertical synchronization signal, a horizontal synchronization signal, a clock signal, etc. (hereinafter, these signals are referred to as “driving signals TSS”) from the video processing unit. The control unit 11 generates a control signal CTL for controlling the compensation unit 14. Also, the control unit 11 receives cumulative data CNT for each pixel from the compensation unit 14. The cumulative data CNT may include the number of times (the number of times of emission) of the data signals input to each of a plurality of sub-pixels included in the pixel, and data of the luminance value of the light emitted from the sub-pixel based on the data signal. The control unit 11 estimates the characteristics of each sub-pixel based on the cumulative data CNT. Specifically, the control unit 11 determines the sub-pixel with the largest deterioration from among the plurality of sub-pixels included in each pixel using the cumulative data CNT. The control unit 11 generates a control signal DCS for driving the data driving unit 12 and a control signal GCS for driving the gate driving unit 13 based on the cumulative data CNT and the driving signals TSS. The control unit 11 transmits the data signal DATA and the control signal DCS to the data driving unit 12. Also, the control unit 11 transmits the control signal GCS and the control signal CTL to the gate driving unit 13 and the compensation unit 14, respectively.

[0013] The data driving unit 12 receives a data signal DATA and a control signal DCS from the control unit 11. The data driving unit 12 uses the control signal DCS to convert the data signal DATA into analog data voltages for each row. The control signal DCS may include a source start pulse signal, a source shift clock signal, a source output enable signal, and the like. The source start pulse signal controls the timing of starting data sampling of a source driver integrated circuit (not shown) included in the data driving unit 12. The source shift clock signal is used to control the timing of data sampling in each of the source driver integrated circuits. The source output enable signal controls the output timing of the signal from the data driving unit 12.

[0014] The data driving unit 12 is electrically connected to each of a plurality of pixels P11 to Pmn included in the display panel 15 via data lines DL1 to DLn. The data driving unit 12 supplies data voltages to each of the pixels P11 to Pmn via the data lines DL1 to DLn. Each of the data lines DL1 to DLn includes a plurality of signal lines. Each of the plurality of signal lines is connected to a plurality of sub-pixels included in each of the pixels P11 to Pmn, respectively. The conversion period and the output period of the data voltage of the data driving unit 12 can be changed by modulating the output width of the data enable signal and the output width of the source output enable signal. The data driving unit 12 continuously supplies the data voltage to each of the pixels P11 to Pmn via the data lines DL1 to DLn while synchronizing with the output timing of a gate signal described later. The plurality of data voltages supplied to the pixels P11 to Pmn respectively correspond to the luminance of the pixels P11 to Pmn. Note that each of the data lines DL1 to DLn may include a plurality of data lines according to the number of sub-pixels included in each of the pixels P11 to Pmn.

[0015] The data driving unit 12 is electrically connected to each of the pixels P11 to Pmn via the reference lines RL1 to RLn. The data driving unit 12 supplies a predetermined reference voltage to each of the pixels P11 to Pmn via the reference lines RL1 to RLn. When the data voltage and the reference voltage are supplied to the pixels P11 to Pmn, the pixels P11 to Pmn can emit light with accurate luminance and accurately acquire (sense) their characteristics. Further, the data driving unit 12 acquires sensing data Sdata of a plurality of sub-pixels included in each of the pixels P11 to Pmn via the reference lines RL1 to RLn. The acquisition of the sensing data Sdata will be described later. The data driving unit 12 transmits the acquired sensing data Sdata to the compensation unit 14

[0016] The gate driving unit 13 receives a control signal GCS from the control unit 11. The gate driving unit 13 is electrically connected to the pixels P11 to Pmn via the gate lines GL1 to GLm. The gate driving unit 13 outputs a gate signal to each of the gate lines GL1 to GLm based on the control signal GCS. The output gate signal is transmitted to the pixels P11 to Pmn via the gate lines GL1 to GLm.

[0017] The gate driving unit 13 may include internal circuits (not shown) such as a level shifter, a shift register, a delay circuit, and a flip-flop. The gate driving unit 13 continuously generates control signals such as a gate start pulse signal, a gate shift clock signal, and a gate output enable signal according to the control signal GCS. The gate start pulse signal controls the timing of the start of the operation of a gate driver integrated circuit (not shown) included in the gate driving unit 13. The gate shift clock signal is a signal commonly input to the gate driver integrated circuit and controls the shift timing of a scanning signal (gate signal). The gate output enable signal specifies the timing information of the gate driver integrated circuit. The gate driving unit 13 continuously generates a gate signal by shifting the gate start pulse signal according to the gate shift clock signal. The gate driving unit 13 supplies the generated gate signal to each of the gate lines GL1 to GLm. The gate signals supplied via the gate lines GL1 to GLm activate each of the plurality of pixels P11 to Pmn. The gate driving unit 13 controls the output width of the gate signal based on the output widths of the data enable signal and the gate output enable signal.

[0018] The gate driving unit 13 supplies the power supply voltage VDD to the pixels P11 to Pmn via the power supply lines PL1 to PLm. Also, the gate driving unit 13 supplies the power supply voltage VSS to the pixels P11 to Pmn. The pixels P11 to Pmn that receive the input of the gate signal from the gate driving unit 13 emit light according to the power supply voltages VDD, VSS, and the data voltage.

[0019] The compensation unit 14 receives the data signal DATA from the video processing unit. The compensation unit 14 generates the cumulative data CNT based on the data signal DATA. The cumulative data CNT may include information about the cumulative value (counting value) of the input value of the data signal DATA to each sub-pixel. That is, the cumulative data CNT may be a value obtained by summing the data signals up to the time point when they are supplied to the sub-pixel based on a predetermined calculation formula. The compensation unit 14 supplies the generated cumulative data CNT to the control unit 11 in response to the control signal CTL from the control unit 11. Further, the compensation unit 14 receives the sensing data Sdata from the data driving unit 12. The sensing data Sdata may include the current value flowing through the driving transistor DT. The compensation unit 14 generates the compensation data Cdata based on the sensing data Sdata. The compensation data Cdata is a data signal in which the non-uniformity of luminance between sub-pixels is compensated. The compensation unit 14 supplies the compensation data Cdata to the data driving unit 12. The operation of the compensation unit 14 will be described later.

[0020] The display panel 15 constitutes the display image of the display device 10. The display panel 15 includes a plurality of pixels P11 to Pmn. The pixels P11 to Pmn are arranged in a matrix in each pixel region defined by the intersection of the gate lines GL1 to GLm extending in the row direction from the gate driving unit 13 and the data lines DL1 to DLn extending in the column direction from the data driving unit 12 (m and n are positive integers, the same hereinafter). By arranging the pixels P11 to Pmn in a matrix, a pixel array is formed in the display panel 15.

[0021] FIG. 2 is a diagram showing a configuration for sensing the characteristics of the pixels P11 to Pmn included in the display device in the present embodiment. In FIG. 2, circuit diagrams of the pixels P11 and P12, which are part of the pixels P11 to Pmn, are shown.

[0022] Pixel P11 and pixel P12 each include four sub-pixels. The four sub-pixels have different emission colors. In this embodiment, pixel P11 includes sub-pixels SP11(R), SP11(W), SP11(B), and SP11(G) corresponding to red, white, blue, and green, respectively. Similarly, pixel P12 includes sub-pixels SP12(R), SP12(W), SP12(B), and SP12(G) corresponding to red, white, blue, and green, respectively. The four sub-pixels SP11(R), SP11(W), SP11(B), and SP11(G) included in pixel P11 share the gate line GL1 and the reference line RL1. Also, the four sub-pixels SP12(R), SP12(W), SP12(B), and SP12(G) included in pixel P12 share the gate line GL1 and the reference line RL2. That is, all the sub-pixels SP11 included in pixel P11 and all the sub-pixels SP12 included in pixel P12 are connected to the common gate line GL1.

[0023] Each of the sub-pixels SP11 included in pixel P11 shown in FIG. 2 includes switching transistors ST1, ST2, a driving transistor DT, a capacitor Cst, and a light-emitting element LED. The gate of the switching transistor ST1 is connected to the gate line GL1. The drain or source of the switching transistor ST1 is connected to the data line DL1. The source or drain of the switching transistor ST1 is connected to the gate of the driving transistor DT and one end of the capacitor Cst. The drain or source of the driving transistor DT is connected to the power line PL1. The source or drain of the driving transistor DT is connected to the other end of the capacitor Cst, the drain or source of the switching transistor ST2, and the anode of the light-emitting element LED. The gate of the switching transistor ST2 is connected to the gate line GL1. The source or drain of the switching transistor ST2 is connected to the reference line RL1. A power supply voltage VSS is supplied to the cathode of the light-emitting element LED. The light-emitting element LED can be an organic light-emitting diode (OLED).

[0024] Each of the sub-pixels SP12 included in the pixel P12 shown in FIG. 2 has the same configuration as the sub-pixel SP11. The gate of the switching transistor ST1 is connected to the gate line GL1 shared with the sub-pixel SP11. The drain or source of the switching transistor ST1 is connected to the data line DL2. The drain or source of the driving transistor DT is connected to the power supply line PL1 shared with the sub-pixel SP11. The gate of the switching transistor ST2 is connected to the gate line GL1 shared with the sub-pixel SP11. The source or drain of the switching transistor ST2 is connected to the reference line RL2.

[0025] When a gate voltage is supplied to the gate line GL1, the data voltage Vdata is stored in the capacitor Cst via the data lines DL1, DL2, and the switching transistor ST1. The data voltage Vdata stored in the capacitor Cst is supplied between the gate and the drain or source of the driving transistor DT. A current corresponding to the data voltage Vdata and the power supply voltages VDD and VSS is supplied to the light-emitting element LED via the driving transistor DT. The light-emitting element LED emits light with a luminance corresponding to the supplied current. Also, when a gate voltage is supplied to the gate line GL1, the sensing data Sdata of the sub-pixel is transmitted to the data driving unit 12 via the switching transistor ST2 and the reference lines RL1 and RL2.

[0026] In the example shown in FIG. 2, 10V + Vth(R) is applied as the data voltage Vdata to the sub-pixel SP11(R) via the data line DL1, and 10V + Vth(W) is applied as the data voltage Vdata to the sub-pixel SP12(W) via the data line DL2. A black data voltage corresponding to black is applied as the data voltage Vdata to the other sub-pixels via the data lines DL1 and DL2. Here, Vth(R) is the threshold voltage of the driving transistor DT of the sub-pixel SP11(R), and Vth(W) is the threshold voltage of the driving transistor DT of the sub-pixel SP12(W). Also, the black data voltage is a voltage for preventing the light-emitting element LED from emitting light, and in this example, the black data voltage is 0V.

[0027] When a gate voltage equal to or higher than the threshold voltage is supplied to the gates of the switching transistors ST1 and ST2 via the gate line GL1, currents corresponding to the data voltage Vdata flow through the driving transistors DT of the sub-pixels SP11(R) and SP12(W), respectively. The current values flowing through the driving transistors DT of the sub-pixels SP11(R) and SP12(W) are transmitted as the sensing data Sdata of the sub-pixels SP11(R) and SP12(W), respectively, to the data driving unit 12 via the reference lines RL1 and RL2. When the sensing data Sdata is transmitted, the control unit 11 may be configured to change the power supply voltage VSS so that the light emitting element LED does not emit light. Since a black data voltage (e.g., 0V) is supplied to the gates of the driving transistors DT of the sub-pixels other than the sub-pixels SP11(R) and SP12(W), no current flows through the driving transistors DT. Therefore, only the sensing data Sdata of the sub-pixel SP11(R), which is a part of the four sub-pixels, is acquired from the pixel P11 via the reference line RL1. Also, only the sensing data Sdata of the sub-pixel SP12(W), which is a part of the four sub-pixels, is acquired from the pixel P12 via the reference line RL2.

[0028] The data driving unit 12 includes a switching unit 121. The data driving unit 12 is connected to the reference lines RL1 and RL2 and the compensation unit 14. The data driving unit 12 supplies the reference voltage Vref from the reference voltage source 16 to each sub-pixel via the switching unit 121, the reference lines RL1 and RL2, and the switching transistor ST2. The switching unit 121 electrically connects the data driving unit 12 and the reference voltage source 16 when the reference voltage Vref is supplied from the reference voltage source 16. The data driving unit 12 initializes each sub-pixel based on the transmitted reference voltage Vref before the characteristics of the sub-pixels are sensed. Also, the switching unit 121 electrically connects the data driving unit 12 and the compensation unit 14 when sensing the characteristics of the sub-pixels. The sensing data Sdata acquired from the sub-pixels is transmitted to the compensation unit 14 via the data driving unit 12.

[0029] FIG. 3 is a block diagram showing a schematic configuration of the compensation unit 14 in the present embodiment. The compensation unit 14 includes a characteristic calculation unit 141, a characteristic storage unit 142, a first compensation data generation unit 143, an accumulation data generation unit 144, a characteristic estimation unit 145, and a second compensation data generation unit 146.

[0030] The characteristic calculation unit 141 receives the sensing data Sdata from the data driving unit 12. The characteristic calculation unit 141 calculates characteristic values CH11, CH12, ··· CHmn of the sub-pixels based on the sensing data Sdata. The characteristic value CH11 is the characteristic value of some of the sub-pixels in the pixel P11, the characteristic value CH12 is the characteristic value of some of the sub-pixels in the pixel P12, and the characteristic value CHmn is the characteristic value of some of the sub-pixels in the pixel Pmn. In the present embodiment, the characteristic value can be the threshold voltage of the driving transistor DT of the sub-pixel for which the sensing operation has been executed. In the example shown in FIG. 2, the characteristic value CH11 is the threshold voltage of the driving transistor DT included in the sub-pixel SP11(R), and the characteristic value CH12 is the threshold voltage of the driving transistor DT included in the sub-pixel SP12(W).

[0031] The characteristic storage unit 142 stores the characteristic values CH11, CH12, ··· CHmn received from the characteristic calculation unit 141. The characteristic storage unit 142 transmits the characteristic value CH1 specified by the control signal CTL1 from among the characteristic values CH11, CH12, ··· CHmn to the first compensation data generation unit 143. The sub-pixel related to the characteristic value CH1 can be the sub-pixel determined by the control unit 11 to have the most significant degradation among the plurality of sub-pixels included in the same pixel.

[0032] Further, the characteristic storage unit 142 transmits the characteristic value CH2 specified by the control signal CTL2 from among the stored characteristic values CH11, CH12, ··· CHmn to the characteristic estimation unit 145 in response to the control signal CTL2 from the control unit 11. The pixel related to the characteristic value CH2 is different from the pixel related to the characteristic value CH1. Also, the emission color of the sub-pixel related to the characteristic value CH2 is different from the emission color of the sub-pixel related to the characteristic value CH1. Furthermore, the characteristic value CH2 can be a plurality of characteristic values obtained from a plurality of pixels.

[0033] The first compensation data generation unit 143 receives the characteristic value CH1 from the characteristic storage unit 142. The first compensation data generation unit 143 generates the first compensation data Cdata1 based on the characteristic value CH1. Specifically, the first compensation data generation unit 143 detects the change amount of the threshold voltage of the driving transistor DT from the characteristic value CH1, and compensates for the detected change amount. The first compensation data Cdata1 can be a data signal corrected based on the characteristic value CH1. The first compensation data generation unit 143 transmits the first compensation data Cdata1 to the data driving unit 12.

[0034] The cumulative data generation unit 144 receives the data signal DATA from the video processing unit. The cumulative data generation unit 144 generates cumulative data based on the data signal DATA. Specifically, the cumulative data generation unit 144 measures the counting values of each sub-pixel based on the data signal DATA, and stores them as cumulative data CNT11, CNT12, ··· CNTmn. The cumulative data CNT11 is the cumulative data of the pixel P11, the cumulative data CNT12 is the cumulative data of the pixel P12, and the cumulative data CNTmn is the cumulative data of the pixel Pmn. The cumulative data CNT11, CNT12, ··· CNTmn can correspond to the deterioration information for each sub-pixel.

[0035] The cumulative data generation unit 144 transmits the stored cumulative data CNT11, CNT12, ··· CNTmn to the control unit 11 in response to the control signal CTL3 from the control unit. The control unit 11 estimates the change in the characteristics of each sub-pixel (for example, the change in the threshold voltage of the driving transistor) based on the cumulative data CNT11, CNT12, ··· CNTmn received from the cumulative data generation unit 144, and determines the sub-pixel estimated to have the most significant degradation. Further, the cumulative data generation unit 144 transmits the cumulative data CNT1 specified by the control signal CTL4 from among the cumulative data CNT11, CNT12, ··· CNTmn to the characteristic estimation unit 145 in response to the control signal CTL4 from the control unit. Note that the specified cumulative data CNT1 may include the counting values of a plurality of sub-pixels included in one pixel. Further, the cumulative data generation unit 144 may extract the luminance value of the light emitted from each sub-pixel from the data signal DATA. The cumulative data CNT11, CNT12, ··· CNTmn generated by the cumulative data generation unit 144 may include information on the extracted luminance value. The information on the measured luminance value may correspond to the degradation information.

[0036] The characteristic estimation unit 145 receives the characteristic value CH2 specified by the control signal CTL2 from the characteristic storage unit 142. Further, the characteristic estimation unit 145 receives the cumulative data CNT1 specified by the control signal CTL4 from the cumulative data generation unit 144. The characteristic estimation unit 145 estimates the characteristic value of the sub-pixel based on the characteristic value CH2 and the cumulative data CNT1.

[0037] Specifically, the characteristic estimation unit 145 estimates the change in the characteristic value of the sub-pixel based on the cumulative data CNT1. Here, the pixel related to the cumulative data CNT1 is the same as the pixel related to the characteristic value CH1 transmitted to the first compensation data generation unit 143. Further, the sub-pixel related to the cumulative data CNT1 is different from the sub-pixel related to the characteristic value CH1 transmitted to the first compensation data generation unit 143.

[0038] Next, the characteristic estimation unit 145 corrects the change in the characteristic value of the sub-pixel calculated from the cumulative data CNT1 based on the characteristic value CH2, and generates an estimated characteristic value EC1. The estimated characteristic value EC1 is the corrected change amount of the characteristic value of the sub-pixel related to the cumulative data CNT1. The estimated characteristic value EC1 can be the corrected change amount of the threshold voltage of the driving transistor DT of the sub-pixel related to the cumulative data CNT1. The pixel related to the characteristic value CH2 is different from the pixel related to the cumulative data CNT1. Further, the pixel related to the characteristic value CH2 is selected from pixels arranged in the vicinity of the pixel related to the cumulative data CNT1. Furthermore, the emission color of the sub-pixel related to the characteristic value CH2 is the same as the emission color of the sub-pixel related to the cumulative data CNT1.

[0039] When generating the estimated characteristic value EC1, the characteristic estimation unit 145 may perform weighting on the characteristic value CH2 and the cumulative data CNT1 according to the distance from the sub-pixel related to the characteristic value CH2 to the sub-pixel related to the cumulative data CNT1. For example, the characteristic estimation unit 145 may give a relatively larger weight to the characteristic value CH2 as the distance from the sub-pixel related to the characteristic value CH2 to the sub-pixel related to the cumulative data CNT1 is smaller. Also, the characteristic estimation unit 145 may give a relatively larger weight to the cumulative data CNT1 as the distance from the sub-pixel related to the characteristic value CH2 to the sub-pixel related to the cumulative data CNT1 is larger. The characteristic estimation unit 145 may generate the estimated characteristic value EC1 based on the weighted cumulative data CNT1 and the characteristic value CH2.

[0040] The characteristic estimation unit 145 transmits the generated estimated characteristic value EC1 to the second compensation data generation unit 146.

[0041] The second compensation data generation unit 146 receives the estimated characteristic value EC1 from the characteristic estimation unit 145. The second compensation data generation unit 146 generates the second compensation data Cdata2 based on the estimated characteristic value EC1. Specifically, the second compensation data generation unit 146 obtains the change amount of the threshold voltage of the driving transistor DT from the estimated characteristic value EC1 and compensates for the change amount. The second compensation data Cdata2 can be a data signal corrected based on the estimated characteristic value EC1. The second compensation data generation unit 146 transmits the second compensation data Cdata2 to the data driving unit 12.

[0042] The data driving unit 12 supplies the first compensation data Cdata1 and the second compensation data Cdata2 to the corresponding sub-pixels. In the first compensation data Cdata1 and the second compensation data Cdata2, the change in the threshold voltage that occurs in the driving transistor DT included in each sub-pixel is compensated. Therefore, the display device according to the present invention can cause all the pixels included in the pixel array to emit light with uniform luminance without variation.

[0043] FIG. 4 is a diagram showing an example of a process in which the control unit 11 in the present embodiment selects a sub-pixel to be sensed. Hereinafter, the process for the pixels P11 and P12 will be mainly described, but the same process can be executed for all the pixels P11 to Pmn included in the display panel.

[0044] The control unit 11 determines the sub-pixel with the most significant degradation from among the plurality of sub-pixels included in each pixel based on the cumulative data CNT11, CNT12, ··· CNTmn. In the example shown in FIG. 4, in the pixel region PA1a, the sub-pixel determined to have the most significant degradation in the 6×6 pixel region including the pixels P11 and P12 is shown. In FIG. 4, R, W, B, and G indicate sub-pixels corresponding to red, white, blue, and green, respectively. That is, in this example, the sub-pixel with the most significant degradation in the pixel P11 is the sub-pixel SP11(R) corresponding to red, and the sub-pixel with the most significant degradation in the pixel P12 is the sub-pixel SP12(B) corresponding to blue.

[0045] In this embodiment, for each pixel, a sub-pixel corresponding to red or white is sensed, and then a sub-pixel corresponding to blue or green is sensed. That is, two sensing operations are performed for each pixel, and sensing data Sdata is obtained from each of the two sub-pixels included in each pixel.

[0046] In this example, a sub-pixel corresponding to red (the first emission color) or white (the second emission color) is sensed first. The control unit 11 selects, as a sensing target, the sub-pixel SP11(R) determined to be the sub-pixel with the most significant degradation among the pixels of P11. On the other hand, the sub-pixel with the most significant degradation among the pixels of P12 is the sub-pixel SP12(B) that does not have red or white as an emission color. The control unit 11 compares the magnitudes of the degradation of the sub-pixel SP12(R) and the sub-pixel SP12(W) of the pixel P12 based on the cumulative data CNT12. In this example, the control unit 11 determines that the sub-pixel SP12(W) has more significant degradation than the sub-pixel SP12(R), and selects the sub-pixel SP12(W) as a sensing target. The control unit 11 performs the same process for other pixels, and selects a sub-pixel corresponding to red or white as a sensing target from each pixel. An example of the sub-pixel selected as a sensing target by the control unit 11 is shown in the pixel region PA1b of FIG. 4. The pixel region PA1b is the same region as the pixel region PA1a.

[0047] Next, sub-pixels corresponding to blue or green are sensed within the same pixel region. The control unit 11 selects, as a sensing target, the sub-pixel SP12(B) determined to be the sub-pixel with the most significant degradation among the pixels of P12. On the other hand, the sub-pixel with the most significant degradation among the pixels of P11 is the sub-pixel SP11(R) corresponding to red. The control unit 11 compares the magnitudes of degradation of the sub-pixels SP11(B) and SP11(G) of the pixel P11 based on the accumulated data CNT11. In this example, the control unit 11 determines that the sub-pixel SP11(G) has more significant degradation than the sub-pixel SP11(B), and selects the sub-pixel SP11(G) as a sensing target. The control unit 11 performs the same process for other pixels, and selects sub-pixels corresponding to blue or green as sensing targets from each pixel. The sub-pixels selected as sensing targets by the control unit 11 are shown in the pixel region PA1c of FIG. 4. The pixel region PA1c is the same region as the pixel regions PA1a and PA1b.

[0048] In pixel P11, the change in the characteristic value of the sub-pixel (first sub-pixel) not selected as the sensing target is estimated based on the cumulative data CNT11 of the first sub-pixel and the characteristic value obtained through sensing from sub-pixels having the same emission color as the first sub-pixel. The control unit 11 can select, from among a plurality of sub-pixels having the same emission color as the first sub-pixel and from which characteristic values are obtained by sensing, the sub-pixel (second sub-pixel) arranged at the position closest to the first sub-pixel in order to estimate the change in the characteristic value of the first sub-pixel. For example, the change in the characteristic value of the sub-pixel SP11(W) included in pixel P11 (first pixel) is estimated by the compensation unit 14 based on the cumulative data CNT11 for the sub-pixel SP11(W) and the characteristic value of the sub-pixel SP12(W) of the sensed pixel P12. Also, the change in the characteristic value of the sub-pixel SP11(B) is estimated by the compensation unit 14 based on the cumulative data CNT11 for the sub-pixel SP11(B) and the characteristic value of the sensed sub-pixel SP12(B). Specifically, the compensation unit 14 corrects the change in the characteristic value of the sub-pixel SP11(W) estimated based on the cumulative data CNT11 for the sub-pixel SP11(W) using the characteristic value of the sub-pixel SP12(W). Similarly, the compensation unit 14 corrects the change in the characteristic value of the sub-pixel SP11(B) estimated based on the cumulative data CNT11 for the sub-pixel SP11(B) using the characteristic value of the sub-pixel SP12(B). The same processing is performed for other pixels, and the change in the characteristic value of the sub-pixel not selected as the sensing target is estimated by the compensation unit 14.

[0049] By performing the process shown in FIG. 4 for all the pixels included in the display panel 15 and all the sub-pixels included in each pixel, it is possible to accurately compensate for luminance non-uniformity over the entire display area of the display device and shorten the time of the sensing operation.

[0050] In addition, within a predetermined range, when sub-pixels corresponding to one emission color are selected based on the accumulated data and exceed a predetermined ratio, the control unit 11 can change the selection of the sub-pixels so as not to exceed the ratio. For example, when sub-pixels corresponding to red (the first emission color) are selected as the object of sensing and exceed a predetermined ratio within a predetermined pixel range, the control unit 11 can exclude a part of the sub-pixels corresponding to the selected red from the object of sensing. Next, the control unit 11 can select sub-pixels corresponding to white (the second emission color) included in the same pixel as the excluded sub-pixels as the object of sensing. Further, when changing the selection of the sub-pixels as the object of sensing, the control unit 11 can select a pixel including two sub-pixels with a relatively small difference in the magnitude of deterioration as the object of the change.

[0051] Furthermore, when the magnitudes of deterioration of two sub-pixels are about the same, the control unit 11 can select the sub-pixel having a larger maximum luminance as the object of sensing. Sub-pixels having white as the emission color have a larger maximum luminance than sub-pixels having red as the emission color. Also, sub-pixels having green as the emission color have a larger maximum luminance than sub-pixels having blue as the emission color. For example, when SP12(R) and SP12(W) have about the same magnitude of deterioration, the control unit 11 can select SP12(W) having a larger maximum luminance as the object of sensing. Also, when SP11(B) and SP11(G) have about the same magnitude of deterioration, the control unit 11 can select SP11(G) having a larger maximum luminance as the object of sensing.

[0052] FIG. 5 is a flowchart showing the steps executed by the display device 10 in the present embodiment. Hereinafter, the steps executed for the pixels P11 and P12 will be mainly described.

[0053] In step S501, the control unit 11 selects sub-pixels to be sensed. In the examples shown in FIGS. 1 to 4, the control unit 11 selects sub-pixels determined to have relatively large degradation based on the accumulated data CNT11 and CNT12. In the example shown in FIG. 4, for pixel P11, the control unit 11 selects sub-pixels SP11(R) and SP11(G) based on the accumulated data CNT11. Also, for pixel P12, the control unit 11 selects sub-pixels SP12(W) and SP12(B) based on the accumulated data CNT12.

[0054] In step S502, the control unit 11 controls the data driving unit 12 and the gate driving unit 13 to supply a data signal and a reference voltage Vref to the selected sub-pixels. In the examples shown in FIGS. 1 to 4, the data driving unit 12 supplies a data voltage Vdata to the selected sub-pixels SP11(R), SP11(G), SP12(W), and SP12(B) via data lines DL1, DL2, and a switching transistor ST1. Also, the data driving unit 12 supplies a black data voltage to sub-pixels not selected by the control unit 11. In the example shown in FIG. 2, the data driving unit 12 supplies the reference voltage Vref to the sub-pixels SP11(R), SP11(W), SP11(B), and SP11(G) included in pixel P11 via a reference line R1 and a switching transistor ST2. Also, the data driving unit 12 supplies the reference voltage Vref to the sub-pixels SP12(R), SP12(W), SP12(B), and SP12(G) included in pixel P12 via a reference line R2 and a switching transistor ST2.

[0055] In step S503, the control unit 11 controls the data driving unit 12 to acquire the characteristics of the selected sub-pixels. In the example shown in FIGS. 1 to 4, the data driving unit 12 first sets the reference line R1 to a floating state, and then, based on the data voltage Vdata, acquires the currents flowing through the driving transistors DT of the selected sub-pixels SP11(R), SP11(G), SP12(W), and SP12(B) as the sensing data Sdata of the sub-pixels, respectively. The data driving unit 12 transmits the acquired sensing data Sdata to the compensation unit 14.

[0056] In step S504, the control unit 11 controls the compensation unit 14 to estimate the characteristics of the sub-pixels not selected as the sensing target and generate an estimated characteristic value EC1. In the example shown in FIGS. 1 to 4, the compensation unit 14 estimates the characteristics of the non-selected sub-pixels SP11(W) and SP11(B) based on the cumulative data CNT11 and the characteristic value CH2 for the sub-pixels SP11(W) and SP11(B). The characteristics estimated by the compensation unit 14 correspond to the estimated characteristic value EC1. The estimated characteristic value EC1 can be the change amount of the threshold voltage of the driving transistor DT of the sub-pixels SP11(W) and SP11(B). Also, the characteristic value CH2 can be the characteristic value obtained by sensing the sub-pixels arranged in the vicinity of the pixel P11. For example, the characteristic value CH2 can be the threshold voltage of the driving transistor DT obtained by the sensing operation for the sub-pixels SP12(W) and SP12(B). Similarly, the compensation unit 14 estimates the characteristics of the non-selected sub-pixels SP12(R) and SP12(G) based on the cumulative data CNT12 and the characteristic value CH2 for SP12(R) and SP12(G). The estimated characteristic value EC1 can be the change amount of the threshold voltage of the driving transistor DT of the sub-pixels SP12(R) and SP12(G). Also, the characteristic value CH2 can be the characteristic value obtained by the sensing operation for the sub-pixels arranged in the vicinity of the pixel P12. For example, the characteristic value CH2 can be the threshold voltage of the driving transistor DT obtained by the sensing operation for the sub-pixels SP11(R) and SP11(G).

[0057] In step S505, the control unit 11 controls the compensation unit 14 to generate the first compensation data Cdata1. In the example shown in FIGS. 1 to 4, the compensation unit 14 calculates characteristic values CH11 and CH12 from the sensing data Sdata acquired in step S503. Next, the compensation unit 14 supplies the first compensation data Cdata1 to the data driving unit 12 as compensated data signals based on the calculated characteristic values CH11 and CH12. The data driving unit 12 supplies the respective first compensation data Cdata1 to the selected sub-pixels SP11(R), SP11(G), SP12(W), and SP12(B).

[0058] In step S506, the control unit 11 controls the compensation unit 14 to generate the second compensation data Cdata2. In the example shown in FIGS. 1 to 4, the compensation unit 14 supplies the second compensation data Cdata2 to the data driving unit 12 as a compensated data signal based on the estimated characteristic value EC1 generated in step S504. The data driving unit 12 supplies the respective second compensation data Cdata2 to the unselected sub-pixels SP11(W), SP11(B), SP12(R), and SP12(G).

[0059] The change in the threshold voltage of the driving transistor for each pixel due to the aging use of the pixel or the like can be estimated from the counting value. The threshold voltage of the driving transistor estimated from the counting value may deviate significantly from the actual threshold voltage obtained by the sensing process due to the usage conditions, usage environment, etc. of the display device. Therefore, in order to compensate for the change in the threshold voltage of the driving transistor with high accuracy, it is desirable to sense all the sub-pixels included in the pixel to obtain the characteristics of the sub-pixels. On the other hand, there is a problem that the sensing process for all sub-pixels requires a long time until the completion of the process. Also, as the display device has higher resolution, the problem of the time required for the sensing process becomes more prominent. In order to shorten the time required for the sensing process, it is conceivable to sense only some of the plurality of sub-pixels included in the pixel in a predetermined pattern. However, since the degree of deterioration varies from pixel to pixel, the sub-pixels whose characteristics should be compensated due to large deterioration may be different for each pixel. Therefore, when selecting the sub-pixels to be sensed using a predetermined pattern, there is a risk that the sub-pixels with a high need for characteristic compensation (i.e., the sub-pixels with the largest deterioration) may not be properly sensed.

[0060] According to the present invention, only some of the plurality of sub-pixels included in the pixel are sensed. As the sub-pixels to be sensed, the sub-pixels with the largest deterioration of the light-emitting element are selected based on the cumulative data including the counting value. Also, for the sub-pixels that are not sensed, the characteristics estimated from the cumulative data of the sub-pixels are corrected using the characteristic values obtained by sensing from the sub-pixels having the same emission color arranged in the vicinity of the sub-pixels. Therefore, the display device according to the present invention can shorten the time of the sensing process while accurately compensating for the non-uniformity of the luminance of the sub-pixels.

[0061] [Second Embodiment] Regarding the display device according to the second embodiment of the present invention, the differences from the first embodiment will be mainly described with reference to FIG. 6.

[0062] FIG. 6 is a diagram showing an example of a process in which the control unit in the present embodiment selects a sub-pixel to be sensed. In the present embodiment, it is different from the first embodiment in that only one sensing operation is performed for each pixel within a predetermined range. Hereinafter, the process for pixels P11 and P12 will be mainly described.

[0063] In the pixel region PA1d of FIG. 6, as an example, sub-pixels determined to be the most deteriorated in a 6×6 pixel region including pixels P11 and P12 are shown. In this example, the sub-pixel most deteriorated among those in pixel P11 is the sub-pixel SP11(R) corresponding to red, and the sub-pixel most deteriorated among those in pixel P12 is the sub-pixel SP12(B) corresponding to blue.

[0064] In the present embodiment, one sub-pixel is sensed for each pixel. That is, one sensing operation is performed for each pixel. Specifically, the control unit 11 selects the sub-pixel SP11(R), which is the sub-pixel most deteriorated among those in pixel P11, as the sensing target. Also, the control unit 11 selects the sub-pixel SP12(B), which is the sub-pixel most deteriorated among those in pixel P12. The control unit 11 performs the same process for other pixels and selects sub-pixels from each pixel. In the pixel region PA1e of FIG. 6, the sub-pixels selected by the control unit 11 are shown. The pixel region PA1e is the same region as the pixel region PA1d.

[0065] In pixel P11, changes in the characteristic values of SP11(W), SP11(B), and SP11(G) that were not selected as sensing targets are estimated by compensation unit 14 based on the cumulative data CNT11 of each sub-pixel and the characteristic values of the sensed sub-pixels within neighboring pixels. For example, the change in the characteristic value of SP11(W) is estimated by compensation unit 14 based on the cumulative data CNT11 for SP11(W) and the characteristic value of the sensed sub-pixel SP21(W). Also, the change in the characteristic value of SP11(B) is estimated by compensation unit 14 based on the cumulative data CNT11 for SP11(B) and the characteristic value of the sensed sub-pixel SP12(B). Further, the change in the characteristic value of SP11(G) is estimated by compensation unit 14 based on the cumulative data CNT11 for SP11(G) and the characteristic value of the sensed sub-pixel SP13(G). Compensation unit 14 can estimate the change in the characteristic value of SP11(G) based on, for example, the characteristic value of sub-pixel SP31(G) in addition to the characteristic value of sub-pixel SP13(G). In this case, compensation unit 14 can estimate the change in the characteristic value of SP11(G) based on, for example, the average value of the characteristic value of sub-pixel SP13(G) and the characteristic value of sub-pixel SP31(G). The same processing is performed for other pixels, and the characteristic values of the unselected sub-pixels are estimated by compensation unit 14.

[0066] By performing the above-described processing for all the pixels included in display panel 15, the time of the sensing operation executed for the entire display area of the display device can be further shortened.

[0067] In addition, within a predetermined range, when sub-pixels corresponding to one emission color are selected based on cumulative data and exceed a predetermined ratio, the control unit 11 can change the selection of the sub-pixels so as not to exceed the ratio. For example, when sub-pixels corresponding to red are selected in excess of a predetermined ratio within a predetermined pixel range, the control unit 11 can exclude some of the selected sub-pixels corresponding to red from the sensing target. Next, the control unit 11 can select sub-pixels corresponding to any one of white, blue, and green included in the same pixel as the excluded sub-pixels. Also, when changing the selection of the sub-pixels, the control unit 11 can select sub-pixels corresponding to the emission color with the fewest number selected within the predetermined range instead of the excluded sub-pixels corresponding to red.

[0068] Furthermore, when the degradation magnitudes of two or more sub-pixels are of the same degree, the control unit 11 can select the sub-pixel having the largest maximum luminance. For example, regarding the four emission colors shown in FIG. 2, red has a higher maximum luminance than blue, green has a higher maximum luminance than red and blue, and white has a higher maximum luminance than green, red, and blue. Therefore, when the degradation magnitudes of two or more sub-pixels are of the same degree, the control unit 11 can most preferentially select sub-pixels having the white emission color as the sensing target, then preferentially select sub-pixels having the green emission color, and then preferentially select sub-pixels having the red emission color.

[0069] Also, within a predetermined range, when sub-pixels corresponding to one emission color are not selected, the control unit 11 can change the selection so that sub-pixels having the one emission color become the sensing target within the predetermined range. For example, when sub-pixels having red as the emission color are not selected within a predetermined pixel range, the control unit 11 can exclude some of the selected sub-pixels having white, blue, and green as the emission colors from the sensing target. Next, the control unit 11 can select sub-pixels corresponding to red included in the same pixel as the excluded sub-pixels. When changing the selection, the control unit 11 can exclude sub-pixels corresponding to the emission color most frequently selected as the sensing target within the predetermined range from the sensing target.

[0070] According to this embodiment, it is possible to further shorten the time of the sensing operation while accurately compensating for unevenness in luminance.

[0071] [Other Embodiments] In the first and second embodiments, the control unit 11 was described as a configuration separate from the compensation unit 14. However, the compensation unit 14 does not necessarily have to be provided separately from the control unit 11. For example, the control unit 11 may be constituted by one chip, the compensation unit 14 may be integrated within the chip of the control unit 11, and the control unit 11 may be configured to provide all the functions of the compensation unit 14.

[0072] Each part and each process described in each embodiment can be realized by a processor and a memory that cooperates with the processor. For example, the processor can read a program stored in the memory, execute the program, and operate each part as described in each embodiment. The processor may be included in each part described in each embodiment. The processor may be a CPU or an MPU. Also, the memory that cooperates with the processor may be a non-volatile memory.

[0073] The configuration of each part and the content of the signals described in each embodiment are not limited to those described above, and can be changed according to the application and purpose. Also, configurations and signals that combine each embodiment are all included in the present invention. That is, the present invention is not limited to the above-described embodiments, and can be modified based on the technical idea of the present invention. For example, the present invention includes a configuration in which the above-described embodiments are organically combined. [Description of Reference Numerals]

[0074] 10 Display device 11 Control unit 12 Data driving unit 13 Gate driving unit 14 Compensation unit 15 Display panel (pixel array) P11, P12 Pixels SP11, SP12 Sub-pixels

Claims

1. A pixel array having a plurality of pixels each including a plurality of sub-pixels and a gate line shared by the plurality of sub-pixels, a gate driving unit that supplies a gate signal to the plurality of sub-pixels via the gate line, a data driving unit that supplies a data signal to each of the plurality of sub-pixels via a data line, a control unit that selects one of the sub-pixels from the plurality of sub-pixels included in the pixel based on deterioration information of the sub-pixels and supplies the data signal from the data driving unit to the selected sub-pixel, and a compensation unit that acquires characteristics of the selected sub-pixel. A display device.

2. The deterioration information is cumulative data obtained by summing up data signals supplied to the sub-pixel up to that point based on a predetermined calculation formula. The display device according to claim 1.

3. Each of the plurality of pixels includes a first sub-pixel that is not selected and a second sub-pixel that is selected. The compensation unit estimates the characteristics of the first sub-pixel of one pixel based on the cumulative data of the first sub-pixel of one pixel and the characteristics obtained from the second sub-pixel of another pixel. The display device according to claim 2.

4. The first sub-pixel of the one pixel has the same emission color as the second sub-pixel of the other pixel. The display device according to claim 3.

5. The compensation unit estimates the characteristics of the first sub-pixel of the one pixel based on the characteristics of the second sub-pixel of the other pixel that is closest to the first sub-pixel among the plurality of the other pixels. The display device according to claim 4.

6. The compensation unit further estimates the characteristics of the first sub-pixel based on the characteristics obtained from the second sub-pixel. The display device according to claim 5.

7. The compensation unit further estimates the characteristics of the first sub-pixel according to the distance from the first sub-pixel to the second sub-pixel. The display device according to claim 6.

8. The control unit selects the sub-pixel estimated to have the greatest deterioration from the plurality of sub-pixels based on the cumulative data. The display device according to claim 2.

9. The compensation unit acquires the characteristics from two of the plurality of sub-pixels. The display device according to claim 8.

10. The plurality of sub-pixels have a first emission color and a second emission color. When the sub-pixel with the most significant degradation does not have the first emission color or the second emission color, the control unit compares the cumulative data of the sub-pixels having the first emission color and the cumulative data of the sub-pixels having the second emission color, and selects the sub-pixel with more significant degradation. The display device according to claim 9.

11. The control unit selects, based on the cumulative data and the maximum luminance of the sub-pixel, a sub-pixel estimated to have the most significant degradation among the plurality of sub-pixels. The display device according to claim 8.

12. When it is determined, based on the cumulative data, that two or more of the plurality of sub-pixels have a similar degree of degradation, the control unit selects the sub-pixel having the largest maximum luminance. The display device according to claim 11.

13. The plurality of sub-pixels have a first emission color and a second emission color. When, within a predetermined pixel range, sub-pixels having the first emission color are selected in a proportion exceeding a predetermined ratio, the control unit excludes a part of the sub-pixels having the first emission color, which are the sub-pixels with the most significant degradation, from the selection target, and selects sub-pixels having the second emission color. The display device according to claim 8.

14. The plurality of sub-pixels have different emission colors from each other. When there is an unselected emission color within a predetermined pixel range, the control unit selects, instead of the sub-pixel with the most significant degradation, a sub-pixel corresponding to the unselected emission color. The display device according to claim 8.

15. The compensation unit generates a data voltage in which a change in the characteristic of the selected sub-pixel is compensated based on the acquired characteristic, and generates a data voltage in which a change in the characteristic of the first sub-pixel is compensated based on the estimated characteristic. The display device according to claim 3.

16. When supplying the data signal to the selected sub-pixel, the data driving unit supplies a black data voltage corresponding to black to sub-pixels other than the selected sub-pixel. The display device according to claim 1.

17. Before supplying the data signal, the data driving unit supplies a predetermined reference voltage to the plurality of sub-pixels via a reference line shared by the plurality of sub-pixels. The compensation unit acquires the characteristic via the reference line. The display device according to claim 1.

18. The control unit selects the sub-pixels respectively from all the pixels included in the pixel array. The compensation unit acquires the characteristics from all the selected sub-pixels respectively. The display device according to claim 1. **Claim 19** Each of the plurality of sub-pixels includes an organic light-emitting diode. The display device according to any one of claims 1 to 18.

Images