KR20160018946A - Organic light emitting diode display and drving method thereof - Google Patents

Abstract

A purpose of the present invention is to provide an organic light emitting diode display device which can reduce a compensation time necessary for compensation while maintaining compensation accuracy of transistor characteristics related to threshold voltage of a driving thin film transistor (TFT) and mobility. According to a first embodiment of the present invention, the organic light emitting diode display device comprises: a display panel including pixel driving circuits including driving transistors (TFT) which are formed in an intersection of a plurality of scan lines and a plurality of data lines, and control an organic light emitting diode and current flowing the organic light emitting diode; a data driver for sensing characteristics of each TFT of a part of the pixel driving circuits through the data line by driving a part of the pixel driving circuits among the pixel driving circuits; and a timing controller for applying an interpolation method to each TFT of the partial pixel driving circuits sensed, and obtaining the characteristics of each TFT of the remaining pixel driving circuits.

Description

Technical Field [0001] The present invention relates to an organic light emitting diode (OLED) display device,

The present invention relates to an organic light emitting diode display and a driving method thereof.

2. Description of the Related Art In recent years, various flat panel displays (FPDs) have been developed to reduce weight and volume, which are disadvantages of cathode ray tubes. Such a flat panel display device includes a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP) And a light emitting device (Electroluminescence Device).

PDP has attracted attention as a display device that is most advantageous for large screen size but small size because of its simple structure and manufacturing process, but it has disadvantage of low luminous efficiency, low luminance and high power consumption. A TFT LCD to which a thin film transistor (hereinafter referred to as "TFT") is applied as a switching element is the most widely used flat panel display device, but it has a problem that the viewing angle is narrow and the response speed is low because it is a light emitting device. On the other hand, the electroluminescent device is divided into an inorganic light emitting diode display device and an organic light emitting diode display device according to the material of the light emitting layer. In particular, the organic light emitting diode display device uses self light emitting devices that emit self- Brightness and viewing angle are large.

The organic light emitting diode display controls the voltage between the gate terminal and the source terminal of the driving transistor to control the current flowing from the drain to the source of the driving transistor.

The current flowing from the drain to the source of the driving transistor flows through the organic light emitting diode and emits light, and the degree of light emission can be controlled by controlling the amount of current.

At this time, since the current of the organic light emitting diode is greatly affected by the threshold voltage (Vth) and mobility of the driving transistor, it is necessary to accurately measure and compensate the threshold voltage (Vth) and the mobility.

For this purpose, many researches on internal compensation and external compensation have been made. However, compensation has to be performed on all the pixels in the display panel, so that there is a problem that much time is required for compensation.

In particular, there has been a problem that the number of pixels in a panel increases as the size of the display device becomes larger, and accordingly, it takes much time to perform compensation.

The organic light emitting diode display device according to the embodiment of the present invention can provide an organic light emitting diode display device and a driving method thereof that can reduce a necessary compensation time for compensating a transistor characteristic related to threshold voltage and mobility of a driving TFT.

The organic light emitting diode display device according to the first embodiment of the present invention includes an organic light emitting diode (OLED) and a driving transistor (hereinafter referred to as " OLED ") for controlling a current flowing in the organic light emitting diode, which is formed at a crossing point of a plurality of scan lines and a plurality of data lines A display panel including pixel driving circuits including TFTs; A data driver for driving some pixel driving circuits of the pixel driving circuits to sense the characteristics of driving TFTs of the pixel driving circuits of the certain pixel driving circuits through the data lines; And a timing controller for applying interpolation to the characteristics of the driving TFTs of each of the sensed pixel driving circuits to obtain characteristics of the driving TFTs of the remaining pixel driving circuits.

In the organic light emitting diode display according to the first embodiment of the present invention, the characteristics of the driving TFTs of the pixel driving circuits connected to odd-numbered scan lines among the scan lines are sensed, and even- The characteristics of the driving TFTs of the pixel driving circuits connected to the lines are acquired by applying the interpolation method to the characteristics of the driving TFTs of the pixel driving circuits connected to the odd-numbered scanning lines.

In the organic light emitting diode display according to the first embodiment of the present invention, the characteristics of the driving TFTs of the pixel driving circuits connected to the odd-numbered data lines of the data lines are sensed, and even- The characteristic of the driving TFT of each of the pixel driving circuits connected to the lines is obtained by applying the interpolation method to the characteristic of the driving TFT of each of the pixel driving circuits connected to the odd-numbered data lines.

In the organic light emitting diode display device according to the first embodiment of the present invention, pixels for sensing the characteristics of the driving TFT and pixels for obtaining characteristics of the driving TFT by interpolation are alternately repeated every frame.

In the organic light emitting diode display device according to the first embodiment of the present invention, the characteristic of the driving TFT of the pixel to which the interpolation method is applied is different from the driving TFT of the pixel to which the interpolation method is applied, Is determined as an average value.

In the organic light emitting diode display device according to the first embodiment of the present invention, each of the pixel driving circuits is controlled by a scan signal on a first scan line of the scan lines, 1 switching TFT, a second switching TFT controlled by a scan signal on a second scan line of the scan lines and connected between a reference voltage line and a second node, a storage capacitor connected between the first and second nodes, Further comprising a light emitting control TFT controlled by a control signal and connected between the high potential power supply and the first node, wherein the driving TFT controls a current flowing in the organic light emitting diode according to a potential difference on the first and second nodes .

The organic light emitting diode display device according to the second embodiment of the present invention is formed at an intersection point of a plurality of scan lines, data lines, sensing lines, and sensing control lines, and includes an organic light emitting diode and a current flowing in the organic light emitting diode A display panel including pixel driving circuits having a driving transistor (hereinafter referred to as a driving TFT) for controlling the pixel driving circuits;

A data driver which drives some pixel driving circuits of the pixel driving circuits and senses characteristics of driving TFTs of the pixel driving circuits through the sensing line; And

And a timing controller that applies interpolation to the characteristics of the driving TFTs of each of the sensed pixel driving circuits to obtain characteristics of the driving TFTs of the remaining pixel driving circuits.

In the organic light emitting diode display device according to the second embodiment of the present invention, the characteristics of the driving TFTs of the pixel driving circuits connected to the odd-numbered scan lines among the scan lines are sensed, The characteristics of the driving TFTs of the pixel driving circuits connected to the lines are acquired by applying the interpolation method to the characteristics of the driving TFTs of the pixel driving circuits connected to the odd-numbered scanning lines.

In the organic light emitting diode display according to the first embodiment of the present invention, the characteristics of the driving TFTs of the pixel driving circuits connected to the odd-numbered data lines of the data lines are sensed, and even- The characteristic of the driving TFT of each of the pixel driving circuits connected to the lines is obtained by applying the interpolation method to the characteristic of the driving TFT of each of the pixel driving circuits connected to the odd-numbered data lines.

In the organic light emitting diode display device according to the first embodiment of the present invention, pixels for sensing the characteristics of the driving TFT and pixels for obtaining characteristics of the driving TFT by interpolation are alternately repeated every frame.

In the organic light emitting diode display device according to the first embodiment of the present invention, the characteristic of the driving TFT of the pixel to which the interpolation method is applied is different from the driving TFT of the pixel to which the interpolation method is applied, Is determined as an average value.

In the organic light emitting diode display device according to the first embodiment of the present invention, each of the pixel driving circuits is a switching TFT controlled by a scan signal on the scan line and connected between the data line and the first node, And a storage capacitor connected between the first and second nodes, wherein the driving TFT is connected to the first node and the second node, and the driving TFT is connected between the second node and the sensing line, And the current flowing through the organic light emitting diode is controlled according to the potential difference.

The organic light emitting diode display device according to the embodiment of the present invention can provide an organic light emitting diode display device capable of reducing the necessary compensation time while maintaining compensation accuracy of the transistor characteristics related to the threshold voltage and mobility of the driving TFT .

1 is a view showing a structure of an organic light emitting diode.
FIG. 2 shows an apparatus for measuring a characteristic parameter of a pixel driving circuit of an organic light emitting diode display device according to a first embodiment of the present invention.
Figs. 3 and 4 show steps of measuring the Vth of the pixel driving circuit according to the first embodiment of the present invention.
5 is a graph showing an output voltage of the data line with time.
Figs. 6 to 9 are step-by-step illustrations of the k-parameter measurement method of the pixel driving circuit according to the first embodiment of the present invention.
Figs. 10 and 11 are driving waveform diagrams of the pixel driving circuit shown in Figs. 6 to 9. Fig.
12 is a diagram showing an apparatus for measuring a characteristic parameter of a pixel driving circuit according to a second embodiment of the present invention.
FIG. 13 is a diagram showing the operation of a switch element in Vth measurement according to the second embodiment of the present invention. FIG.
14 shows an operation diagram of the pixel driving circuit in the first initialization period.
Fig. 15 shows an operation diagram of the pixel driving circuit in the first sensing period.
16 shows an operation diagram of the pixel driving circuit in the first sampling period.
FIG. 17 is a diagram showing the operation of the switch element in the k-parameter detection according to the second embodiment of the present invention. FIG.
18 shows an operation diagram of the pixel driving circuit in the second initialization period.
19 shows an operation diagram of the pixel driving circuit in the second sensing period.
20 shows an operation diagram of the pixel driving circuit in the second sampling period.
21 is a block diagram showing an organic light emitting diode display device according to the first embodiment of the present invention.
22 is a block diagram showing an organic light emitting diode display device according to a second embodiment of the present invention.
23 to 31 are diagrams showing the Vth and k parameter detection methods according to the embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Hereinafter, an organic light emitting diode display according to an embodiment of the present invention and a driving method thereof will be described in detail with reference to the drawings. The following embodiments are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the size and thickness of an apparatus may be exaggerated for convenience. Like reference numerals designate like elements throughout the specification.

≪ Structure of organic light emitting diode &

1 is a view showing a structure of an organic light emitting diode.

The organic light emitting diode display device may have an organic light emitting diode (OLED) as shown in FIG.

The organic light emitting diode may include organic compound layers (HIL, HTL, EML, ETL, EIL) formed between the anode electrode and the cathode electrode.

The organic compound layer includes a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL), and an electron injection layer EIL).

When a driving voltage is applied to the anode electrode and the cathode electrode, holes passing through the HTL and electrons passing through the ETL are transferred to the EML to form excitons, Thereby generating visible light.

The organic light emitting diode display device arranges the pixels including the organic light emitting diode in a matrix form and controls the brightness of the pixels selected by the scan signal according to the gray level of the digital video data.

Such an organic light emitting diode display device is divided into a passive matrix type and an active matrix type using a TFT as a switching element.

Among these, the active matrix method selects a pixel by selectively turning on the TFT as the active element and maintains the light emission of the pixel with the voltage held in the storage capacitor.

Hereinafter, a method and an apparatus for measuring characteristic parameters of a pixel driving circuit of an organic light emitting diode display device according to the present invention will be described in detail. The pixel driving circuit to be described below may be any one of red, green, blue, and white.

The current Ids of the driving TFT for determining the amount of OLED light emission of each pixel in the organic light emitting diode display device is determined by the driving TFT characteristic parameters such as the Vth and k parameters of the driving TFT in addition to the driving voltage Vgs of the driving TFT, .

Equation 1

), 기생 커패시턴스(Cox)와 같은 공정 특성 성분들을 포함한다. 구동 TFT의 Vth 및 k 파라미터는 동일한 구동 전압(Vgs) 대비 구동 TFT의 전류가 불균일하게 함으로써 휘도를 불균일하게 하는 원인 성분이므로, 본 발명에서는 검사 공정 및/또는 표시 구동중에 각 화소별로 Vth 및 k 파라미터를 측정하기로 한다.In Equation (1), k represents a process characteristic factor, and is a channel width (W) / channel length (L), a mobility

), And parasitic capacitance (Cox). Since the Vth and k parameters of the driving TFT are the cause components that make the luminance uneven by making the current of the driving TFT nonuniform with respect to the same driving voltage (Vgs), in the present invention, Vth and k parameters .

The characteristic parameter measurement method and apparatus of the pixel drive circuit according to the present invention can drive the drive TFTs of the respective pixel drive circuits constant current and measure the Vth and k parameters of the drive TFT individually through the data lines and the data driver, The sensing line may be provided and measured through the sensing line.

≪ First Embodiment of the Present Invention: Structure of P-type Pixel Driver Circuit >

FIG. 2 shows an apparatus for measuring a characteristic parameter of a pixel driving circuit of an organic light emitting diode display device according to a first embodiment of the present invention.

The transistor included in the pixel driving circuit according to the first embodiment of the present invention may be a P-type transistor. The P-type transistor may be LTPS (Low Temp Poly Silicon).

The characteristic parameter measuring apparatus of the pixel driving circuit shown in FIG. 2 includes a display panel 100 on which a pixel driving circuit is formed, a driving circuit for driving the data lines DL of the display panel 100, A timing controller 400 for detecting and compensating characteristic parameters such as Vth and k parameter deviations from the measured voltage of the data driver 200, Respectively.

The data driver 200 and the timing controller 400 become characteristic parameter detecting means. 2 includes a gate driver 300 for driving the scan lines SL1 and SL2 of the pixel drive circuit and a light emission control part for driving the light emission control line EL ).

The organic light emitting diode display device shown in FIG. 2 can be divided into a measurement mode for measuring characteristic parameters of each pixel driving circuit and a display mode for normal image display.

The data driver 200 includes a digital-to-analog converter (DAC) 210 and an analog-to-digital converter (ADC) connected in parallel with each data line DL, A first switch SW1 connected between the DAC 210 and the data line DL and a sampling / holder (S / H) connected between the ADC 220 and the data line DL. 230). An output buffer (not shown) may further be provided between the DAC 210 and the first switch SW1.

The DAC 210 converts the input data from the timing controller 400 into the analog data voltage Vdata and outputs the analog data voltage Vdata to the data line DL of the display panel 100 through the first switch SW1 Supply. In the measurement mode, the sampling / holder 230 measures and outputs a voltage for calculating the Vth and k parameters of each pixel driving circuit through the data line DL, and the ADC 220 converts the measured voltage into digital data, do.

Each pixel driving circuit includes first and second switching TFTs SC1 and SC2 for independently driving the OLED, a driving TFT DT, a light emission control TFT ET and a storage capacitor Cs. The pixel driving circuit also includes first and second scan lines SL1 and SL2 for supplying the first and second scan signals SS1 and SS2 to the control signals of the first and second switching TFTs SC1 and SC2, A light emission control line EL for supplying a light emission control signal EM with a control signal of the light emission control TFT ET and a precharge voltage Vpre and a data voltage Vdata to the first switching TFT SC1 A reference voltage line RL for supplying a reference voltage Vref to the second switching TFT SC2 and a data line DL for supplying a high potential power supply VDD to the emission control TFT ET. 1 power supply line PL1 and a second power supply line PL2 for supplying a low potential power supply VSS to the cathode of the OLED. Then, the pixel drive circuit is driven in a measurement mode for measuring the Vth and k parameter deviations of the drive TFT (DT) and a display mode for data display.

The OLED is connected in series with the driving TFT DT between the first power supply line PL1 and the second power supply line PL2. The OLED has an anode connected to the driving TFT (DT), a cathode connected to the second power supply line (PL2), and a light emitting layer between the anode and the cathode. The light emitting layer includes an electron injection layer, an electron transport layer, an organic light emitting layer, a hole transport layer, and a hole injection layer sequentially stacked between the cathode and the anode. In the OLED, when a positive bias is applied between the anode and the cathode, electrons from the cathode are supplied to the organic light emitting layer via the electron injection layer and the electron transport layer, and holes from the anode are supplied to the organic light emitting layer via the hole injection layer and the hole transport layer do. Accordingly, in the organic light emitting layer, the fluorescent material or the phosphorescent material is caused to emit light by the recombination of the supplied electrons and holes, thereby generating a luminance proportional to the current density.

The first switching TFT SC1 has a gate electrode connected to the first scan line SL1, a first electrode connected to the data line DL, a first node connected to the first electrode of the driving TFT DT N1 are connected to the second electrode. The first electrode and the second electrode are a source electrode and a drain electrode according to a current direction. In the measurement mode, the first switching TFT SC1 receives the pre-charge voltage Vpre from the data line DL in response to the first scan signal SS1 supplied from the gate driver 300 to the first scan line SL1, To the first node N1. The first switching TFT SC1 supplies the data voltage Vdata from the data line DL to the first node N1 in response to the first scan signal SS1 of the first scan line SL1 in the measurement mode and the display mode, .

The second switching TFT SC2 has a gate electrode connected to the second scan line SL2, a first electrode connected to the reference voltage line RL, and a second node connected to the gate electrode of the drive TFT DT N2 are connected to the second electrode. The first electrode and the second electrode are a source electrode and a drain electrode according to a current direction. In the measurement mode and the display mode, the second switching TFT ST2 receives the reference voltage Vref from the reference voltage line RL in response to the second scan signal SS2 supplied from the scan driver to the second scan line SL2, To the second node N2.

The storage capacitor Cs is connected between the data voltage Vdata and the reference voltage Vref and the difference voltage between the precharge voltage Vpre and the reference voltage Vref supplied to the first and second nodes N1 and N2, And supplies it to the driving voltage Vgs of the driving TFT DT.

The driving TFT DT has a gate electrode connected to the first node N1, a first electrode connected to the first power supply line PL1 via the emission control TFT ET, and a second electrode connected to the second node N2 And a second electrode is connected. The first electrode and the second electrode are a source electrode and a drain electrode according to a current direction. The driving TFT DT supplies a current corresponding to the driving voltage Vgs supplied from the storage capacitor Cs to the OLED to emit the OLED.

The light emitting control TFT ET has a gate electrode connected to the emission control line EL, a first electrode connected to the first power supply line PL1, and a second electrode connected to the first node N1. The first electrode and the second electrode are a source electrode and a drain electrode according to a current direction. The emission control TFT ET supplies the high potential power supply Vdd to the drive TFT DT only in the display period of the display mode in response to the emission control signal EM supplied from the emission control section to the emission control line EL, And in the non-display period of the measurement mode and the display mode, the high-potential power source (Vdd) is cut off to prevent the black luminance from rising.

In the display mode, the first switch SW1 is turned on. The DAC 210 converts the input data to the data voltage Vdata and supplies the data voltage Vdata to the data line DL through the first switch SW1. When the first and second switching TFTs SC1 and SC2 of the pixel driving circuit are turned on in response to the first and second scan signals SS1 and SS2, the storage capacitor Cs is turned on and the data voltage Vdata And charges the difference voltage (Vdata-Vref) from the reference voltage (Vref). The first and second switching TFTs ST1 and ST2 are turned off in response to the first and second scan signals SS1 and SS2 and the emission control TFT ET is turned on in response to the emission control signal EM. -, the driving TFT DT supplies a driving current corresponding to the voltage charged in the storage capacitor Cs to the OLED so as to emit the OLED.

In the measurement mode, the data driver 10 is configured to drive the drive TFT DT of each pixel drive circuit constant current and to calculate the Vth and k parameters of the drive TFT DT of each pixel drive circuit through the data line DL The voltage is sequentially measured and output. Specific methods of measuring the Vth and k parameters will be described later.

The timing controller 400 detects characteristic parameters such as Vth and k parameter deviations according to a predetermined arithmetic expression using the measured voltage from the data driver 200, and outputs the offset value (offset) for the detected Vth compensation, a gain value for k-parameter deviation compensation is set and stored in an internal memory (not shown) on a pixel-by-pixel basis. The timing controller 400 compensates the input data using the offset value and the gain value stored in the memory, and supplies the compensated data to the data driver 200 with the characteristic parameters of each pixel driving circuit.

≪ Vth Measurement and Compensation Method According to First Embodiment >

FIGS. 3 and 4 are diagrams illustrating a method of measuring Vth of a pixel driving circuit according to the first embodiment of the present invention, and FIG. 5 is a graph illustrating an output voltage of the data line according to time.

As shown in FIG. 3, the DAC 210 supplies the precharge voltage Vpre to the data line DL through the first switch SW1 turned on. The precharge voltage Vpre may be supplied from the external voltage source to the data line DL through the first switch SW1.

Then, the first switch SW1 is turned off and the first and second switching TFTs SC1 and SC2 are turned on as shown in Fig. The drive TFT DT is driven in the saturation region by the difference voltage between the precharge voltage Vpre charged in the storage capacitor Cs and the reference voltage Vref and the precharge voltage Vpre of the data line DL (Vpre) is discharged through the OLED and the first switching TFT SC1 and the driving TFT DT. When the voltage of the storage capacitor Cs reaches Vth of the driving TFT DT due to the discharge of the precharge voltage Vpre, the voltage of the data line DL becomes saturated. The sampling / holder 230 measures and outputs the voltage Vsen of the data line DL at the time point of saturation T1 and the ADC 220 outputs the measured voltage from the sampling / And outputs it.

The timing controller 400 calculates the reference voltage Vref, the measured voltage Vsen and the difference voltage Vref-Vsen to detect Vth of the driving TFT DT and sets an offset value for compensating the detected Vth And stores the data for each pixel.

≪ K-parameter measurement and compensation method according to the first embodiment >

Figs. 6 to 9 are step-by-step diagrams of the k-parameter measurement method of the pixel drive circuit according to the first embodiment of the present invention, and Figs. 10 and 11 are drive waveforms of the pixel drive circuit shown in Figs. 6 to 9 .

10, the DAC 210 is turned on in the same manner as described in the "Vth measurement and compensation method step" on the data line DL via the first switch SW1 turned on as shown in Fig. (Vimage + Vth + Vref) of the compensated data voltage (Vdata = Vimage + Vth) and the reference voltage (Vref) by applying the detected Vth. In this programming period, the first and second switching TFTs SC1 and SC2 are turned on by the first and second scan signals SS1 and SS2 so that the storage capacitor Cs is turned on by the data voltage Vdata = Vimage + Vth) and supplies it to the driving voltage Vgs of the driving TFT DT. Accordingly, the driving TFT DT supplies a current Ids proportional to the k-parameter and the data voltage Vimage to the OLED as shown in the following equation (2). (Equation 2 can be obtained by substituting Vimage + Vth + Vref in Equation 1)

Equation 2

10, the DAC 210 charges the data line DL with the precharge voltage Vpre through the first switch SW1, and applies the precharge voltage Vpre to the data lines DL through the first and second scan The first and second switching TFTs SC1 and SC2 are turned off by the signals SS1 and SS2.

8, the first switch SW1 is turned off so that the data line DL is floated and the first switching TFT SC1 is turned on by the first scan signal SS1 And the second switching TFT SC2 is turned off by the second scan signal SS2. Thus, as the driving TFT DT operates in the saturation region and the pre-charge voltage Vpre of the data line DL is discharged through the OLED and the first switching TFT SC1 and the driving TFT DT, So that the voltage of the load cell DL falls. At this time, the voltage across the storage capacitor Cs also varies with the voltage on the second node N2 in accordance with the voltage change on the first node N1 in accordance with the electrostatic induction phenomenon, so that the driving voltage Vgs of the driving TFT DT, Can be kept constant.

Referring to FIG. 10, it can be seen that the slope of the voltage change in the reference pixel and the measurement pixel, that is, the voltage change amount (? Ref,?) Differs according to the characteristics of the k-parameter of the driving TFT DT. This is because the K parameter characteristics of each of the driving TFTs DT in the pixel are different and the current driving capability of the driving TFT DT is different according to the K parameter characteristic, so that the amount of current flowing to the OLED is changed.

10, the first switching TFT ST1 is turned off by the first scan signal SS1 as shown in Fig. 9, and then the sampling / holder 230 is turned on / off at the data line DL and outputs the measured voltage Vsen through the ADC 220. [

The timing controller 400 calculates the difference voltage (? Ref = Vpre-Vsen0) between the precharge voltage Vpre and the measured voltage Vsen0 of the reference pixel measured at the sensing time Tsen, (K) between the reference pixel and the measurement pixel by calculating the ratio of the difference voltage (? = Vpre-Vsen1 or Vsen2) between the precharge voltage (Vpre) of the measurement pixel and the measurement voltage (Vsen1 or Vsen2) Parameter ratio), and detects and stores a gain value for compensating the k-parameter deviation between pixels from the detected k-parameter ratio.

In other words, the timing controller 400 calculates the ratio of the voltage variation (? Ref = Vpre-Vsen0) of the reference pixel to the voltage variation (? = Vpre-Vsen1 or Vsen2) of the measurement pixel during the discharge period Pixel k parameter deviation and detects and stores a gain value for compensating the detected k parameter deviation.

The current amount of the driving TFT DT is calculated using the difference voltage (? = Vpre-Vsen) between the pre-charge voltage Vpre and the measurement voltage Vsen shown in Fig. 11, K parameter ratio between the pixel and the measurement pixel) can be detected.

Specifically, in the discharge period of FIG. 10, the driving TFT DT operates in the saturation region, so? Can be found to be proportional to the current of the driving TFT DT as shown in the following equation (3).

In Equation 3 derived from the voltage-current relationship of the capacitor below, Cload is the load on the data line DL, i.e., the parasitic capacitance of the data line DL.

Equation 3

Since the discharge period and the Cload are the same and the Vth of the driving TFT DT is compensated, It can be seen that the ratio is the same as the current ratio between the reference pixel and the measurement pixel, and is the same as the ratio of the k parameter between the reference pixel and the measurement pixel. Also, the ratio is measured in the specific sensing time Tsen And the ratio of the measured voltage between the reference pixel and the measurement pixel is the same. Therefore, the deviation of the k-parameter between the pixels (i.e., the ratio of the k parameter between the reference pixel and the measurement pixel) can be simply calculated as the ratio of the measurement voltage Vsen0 of the reference pixel to the measurement voltage Vsen1 or Vsen2 of the measurement pixel .

Equation 4

On the other hand, Vdata for compensating the Vth and k parameters is expressed by Equation (5) below. Ratio.

Equation 5

When Vdata calculated from Equation (5) is substituted into the current equation as shown in Equation (6) below, it can be seen that Ids is an equation that is independent of the characteristics of the Vth and k parameters of the driving TFT (DT) and is therefore compensated.

Equation 6

In other words, since the voltage (Vgs) for driving the driving TFT (DT) is the voltage with which Vth is compensated, the current of the driving TFT (DT) can be calculated by the following equation (7).

Equation 7

Since the reference pixel having the standard k 'parameter and the driving TFT DT of the measurement pixel having the k parameter must be the same, the driving voltage (V'data) of the reference pixel and the driving voltage The voltage (Vdata) can be expressed by the ratio of the standard k 'parameter of the reference pixel to the k parameter of the measurement pixel.

Equation 8

Therefore, the Vth and k parameters of the driving TFT of the measurement pixel are set to the data voltage (Vth) and the offset voltage (offset) for compensating the Vth and the gain value for compensating the k- Vdata). The data can be compensated by multiplying the input data voltage Vdata by the gain value and then adding the offset value Offset.

Equation 9

≪ Second Embodiment of the Present Invention: Structure of N-type Pixel Driver Circuit >

12 is a diagram showing an apparatus for measuring a characteristic parameter of a pixel driving circuit according to a second embodiment of the present invention.

The transistor included in the pixel driving circuit according to the second embodiment of the present invention may be an N-type transistor.

The pixel driving circuit to be described below may be any one of red, green, blue, and white.

The characteristic parameter measuring apparatus of the pixel driving circuit shown in Fig. 12 includes a display panel 100 in which a pixel driving circuit is formed and a data line driving circuit (not shown) for driving the data line DL of the display panel 100, A data driver 200 for measuring a voltage for characteristic parameters of each pixel driving circuit and a timing controller 400 for detecting and compensating characteristic parameters such as Vth and k parameter deviations from the measured voltage of the data driver 200 do.

The data driver 200 and the timing controller 400 serve as characteristic parameter detecting means for the driving TFT DT of each of the pixels.

The data driver 200 according to the second embodiment of the present invention includes a sampling switch Sam and an initial voltage application switch Sinit for applying an initial voltage value, a sensing circuit 240, an ADC (Analog to Digital Converter) A memory 260, a controller 270, an initial voltage generator 280, and a data signal output unit 290.

The initial voltage generator 280 may include a digital-to-analog converter, and an output buffer (not shown) may be connected between the initial voltage generator 280 and the initial voltage application switch May be further provided.

The pixel driving circuit may include a switching TFT (SC), a driving TFT (DT), and a sensing TFT (SE) and an OLED. The switching TFT SC may be controlled by the scan signal SS of the scan line SL and may be connected between the data line DL and the A node.

The driving TFT DT may be controlled by a potential difference between the A node and the B node, and may be connected between the first driving power supply Vdd and the B node. The sensing TFT SE can be controlled by the sensing control signal SCS on the sensing control line SCL and can be connected between the B node and the C node. Further, a storage capacitor Cs may be connected between the node A and the node B. The data line DL may be connected to a data signal output unit 290 and a data signal may be provided from the data signal output unit 290 to the data line DL.

The initial voltage application switch (Sinit) may be turned on when the Vth measurement and the k-parameter measurement are performed to supply the initialization voltage supplied from the initial voltage generator 280 to the pixel sensing line SEL. A control signal for controlling the initial voltage application switch (Sinit) may be provided from the timing controller 400.

The sampling switch Sam is turned on by a sampling signal at a high level during Vth measurement and k-parameter measurement so that the sensing circuit 240 can detect the sensing voltage on the sensing line SEL . The sampling signal Sam for controlling the sampling switch Sam may be provided from the timing controller 400. [

The initial voltage application switch SW20 and the sampling switch SW10 are turned off during the first and second sensing periods Tse1 and Tse2 to float the C and B nodes on the sensing lines SEL1 to SELk .

The ADC 220 may convert the sensing voltage on the sensing line SEL detected by the sensing circuit 240 into a digital value and provide the digital value to the memory 260. The memory 260 stores the digital value , Information on the Vth and K parameters of the driving TFT DT in the pixel driving circuit can be stored.

The controller 270 supplies information on the Vth and K parameters of the driving TFT DT in the pixel driving circuit stored in the memory 260 to the timing controller 400. The timing controller 400 controls the data driver 200 can provide the compensated data voltage to the data line DL.

Thus, the Vth and K parameter characteristics can be compensated by considering the information on the Vth and K parameters of the driving TFT (DT) in the pixel driving circuit.

≪ Vth Measurement and Compensation Method According to Second Embodiment >

FIG. 13 is a diagram showing the operation of a switch element in Vth measurement according to the second embodiment of the present invention. FIG. 15 is an operation diagram of the pixel driving circuit in the first sensing period, and Fig. 16 is a circuit diagram showing the operation of the pixel driving circuit in the first sampling period Fig.

Referring to FIG. 13, the Vth measuring period is divided into a first initializing period Ti1, a first sensing period Tse1, and a first sampling period Tsa1.

In the first initialization period Ti1,

14, in the first initialization period Ti1, the switching TFT SC and the sensing TFT SE are turned on in response to a high-level signal, whereby the initialization voltage Vinit supplied to the sensing line SEL The sensing TFT SE can be turned on and the initialization voltage Vinit on the C-node can be switched to the B-node in response to the sensing control signal SCS on the sensing control line SCL . At the same time, the first reference voltage Vref1 supplied from the data signal output unit 290 to the data line DL can be supplied to the A node. At this time, the first reference voltage Vref1 is set higher than the initialization voltage Vinit in order to conduct the driving TFT DT. In addition, the second driving voltage Vss is reverse-driven by applying a voltage higher than the voltage on the B-node to prevent the current flowing into the OLED.

In the first initializing period Ti1, the node A is charged to the first reference voltage Vref1 and the node B is charged to the initializing voltage Vinit. Since the gate-source voltage Vgs (potential difference between the AB nodes) of the driving TFT DT is larger than Vth in the first initialization period Ti1, the driving TFT DT is turned on, The current has an appropriate initialization value.

In the first sensing period Tse1,

Referring to FIG. 15, supply of the initialization voltage Vinit to the sensing line SEL is stopped in the first sensing period Tse1. That is, since the initial voltage application switch (Sinit) is turned off, the B node becomes a floating state, and the current Ids flowing on the driving TFT DT continues to flow, so that the voltage of the B node rises. When the voltage on the B-node rises and the gate-source voltage Vgs of the driving TFT DT reaches the threshold voltage Vth of the driving TFT DT, the driving TFT DT is turned off, The threshold voltage Vth of the TFT DT is detected in the source follower manner and reflected to the potentials of the nodes B and C.

In the first sampling period Tsa1,

Referring to FIG. 16, the threshold voltage Vth can be measured while the voltage on the C-node is supplied to the sensing circuit 240 by the sampling signal Sampling in the first sampling period Tsa1. The voltage on the C node detected by the sensing circuit 240 is converted into a data signal by the ADC 250 to detect the degree of compensation of the threshold voltage Vth of the driving TFT DT.

As described above, the second embodiment according to the present invention can operate in an external compensation scheme that can obtain data for compensating the threshold voltage (Vth) of the driving TFT DT by feeding back the voltage on the C-node.

≪ K-parameter measurement and compensation method according to the second embodiment >

FIG. 17 is a diagram showing the operation of the switch element in the k-parameter detection according to the second embodiment of the present invention. FIG. 19 shows the operation of the pixel driving circuit in the second sensing period. Fig. 20 shows the operation of the pixel driving circuit in the second sampling period. Fig. Fig.

The k-parameter detection period is divided into a second initialization period Ti2, a second sensing period Tse2, and a second sampling period Tsa2.

In the second initialization period Ti2,

Referring to FIG. 18, in the second initialization period Ti2, the nodes A, B, and C are initialized to specific voltages.

In the second initialization period Ti2, the switching TFT SC and the sensing TFT SE can be turned on in response to the high-level signal, thereby supplying the initialization voltage Vinit supplied to the sensing line SEL to the node B The second reference voltage Vref2 = Vdata + Vth + Vinit, which is the sum of the threshold voltage Vth of the drive TFT DT and the initialization voltage Vinit, can be supplied to the node A at the same time.

At this time, the second reference voltage Vref2 is set higher than the initialization voltage Vinit in order to make the driving TFT DT conductive.

Also, the initialization voltage Vinit may be set to a suitably low value in consideration of the second driving power source Vss so that the OLED does not emit light in the remaining period except for the light emitting period.

In the second initializing period Ti2, the node A is charged to the second reference voltage Vref2 and the node B is charged to the initializing voltage Vinit.

The driving TFT DT is turned on because the gate-source voltage Vgs of the driving TFT DT is larger than the threshold voltage Vth in the second initializing period Ti2 and the current flowing in the driving TFT DT Has an appropriate initialization value.

In the second sensing period Tse2,

Referring to Fig. 19, the second sensing period Tse2 is a period for compensating the k parameter of the driving TFT DT.

The data voltage (second reference voltage Vref2) reflecting the threshold voltage Vth of the drive TFT DT is supplied to the node A during the threshold voltage (Vth) detection period, have.

Equation 10

That is, since the threshold voltage Vth is reflected, it is understood that the current flowing through the OLED is affected by the k-parameter.

The switching TFT SC is turned off by the low level scan signal SS in the second sensing period Tse2 and supply of the initialization voltage Vinit is stopped to the sensing line SEL.

The supply of the initialization voltage Vinit is stopped and the node B becomes a floating state and the voltage of the node B rises due to the drive current Ids of the drive TFT DT and is in the floating state, The voltage between the gate and the source of the driving TFT DT can be kept constant while the voltage of the node A due to the electrostatic induction phenomenon of the capacitor Cs is also raised so that the driving TFT DT can operate as a current source have. The parasitic capacitor Cload on the sensing line SEL can be charged by the current flowing in the driving TFT DT.

That is, the current flows into the parasitic or floating capacitor Cload on the sensing line SEL and the C and B nodes are charged.

According to FIG. 17, the voltages on the C-node are represented by three types.

It can be seen that the waveforms on the C-node are different because the K-parameter characteristics of each of the driving TFTs DT in the pixel are different and the current driving capability of the driving TFT DT is different according to the K- Because the amount of current flowing to the gate is varied.

The parasitic capacitor Cload on the sensing line SEL will be charged quickly if the driving TFT DT has a high mobility and will be charged slowly if the mobility is low.

Thus, the final voltage value in the sampling period on the C-node can be varied according to the k-parameter of the driving TFT DT, and by detecting this, the compensation data on the k-parameter of the driving TFT DT can be obtained for each pixel.

In the second sampling period Tsa2,

Referring to FIG. 20, the switching TFT SC is turned on by the high level scan signal SS in the second sampling period Tsa2, and the black data Vblack is applied to the data line DL have. This is because when the voltage on the B-node is higher than the threshold voltage of the OLED in response to the B-node voltage rise, the OLED can turn on and emit light. Therefore, in order to prevent the OLED from emitting light, black data (Vblack) is applied to the node A so that current does not flow in the driving TFT (DT).

At this time, when the switching TFT SC is turned on by the high level scan signal SS, the voltage on the B-node does not rise and can have a constant value, so that the voltage on the C-node is also kept constant . Since the voltage on the C-node is maintained at a constant level, the sensing circuit 240 can measure the voltage on the C-node by the sampling signal Sam to compensate for the deviation according to the k-parameter.

The formula for the compensation principle of the k parameter is as described in the first embodiment.

≪ Block Diagram of Organic Light Emitting Diode Display Apparatus According to First Embodiment >

21 is a block diagram showing an organic light emitting diode display device according to the first embodiment of the present invention.

Referring to FIG. 21, the organic light emitting diode display device according to the first embodiment of the present invention may include a display panel 100, a gate driver 118, a data driver 200, and a timing controller 400.

개의 화소들을 구비할 수 있다.The display panel 100 includes m data lines DL1 to DLm, which are m-to-one corresponded to each other, and n scan lines SL1 to SLn,

Pixels.

Signal lines for supplying the first driving power source (Vdd) and signal lines for supplying the second driving power source (Vss) may be formed on the display panel (100). Here, the first driving power supply Vdd and the second driving power supply Vss may be generated from the high potential driving voltage source VDD and the low potential driving voltage source VSS, respectively.

The gate driver 300 generates a scan signal SS in response to a gate control signal GDC from the timing controller 400 and sequentially supplies the scan signal SS to the scan lines SL1 to SLn.

The data driver 200 can be controlled by the data controller DDC from the timing controller 400 and can output the data voltage to the data lines DL1 to DLm.

Each of the data lines DL1 to DLm may be connected to each pixel to apply a data voltage to each of the pixels.

The data driver 200 and the timing controller 400 can detect the Vth and k parameters of each of the driving TFTs DT of the pixels on the display panel 100 to compensate the characteristics of the driving TFT DT. At this time, the Vth and k parameters of the driving TFT DT are detected for only some of the pixels of the display panel 100 per frame, and are supplied to the data driver 200. The Vth and k parameters of the driving TFT DT of the remaining pixels Can be obtained by interpolation from the Vth and k parameters of the drive TFT DT detected.

That is, the ratio of the number of pixels to be sensed can be determined by a ratio of 1 / n (n is a natural number), and when n is 2, only the half of all pixels are sensed per frame, .

Thus, the compensation time can be reduced by compensating the characteristics of some pixels among all the pixels for the driver TFT (DT), and the characteristics for the remaining driver TFT (DT) can be obtained by interpolation to reduce the compensation time It is possible to achieve the effect of improving image quality. In particular, the increase in the compensation time can be reduced in proportion to the increase in the number of pixels according to the large area of the display panel 100.

The timing controller 400 may calculate the characteristic value of the driving TFT DT of the pixels not sensed by applying the interpolation method to the characteristic of the driving TFT DT of the sensed pixels supplied from the ADC 220, It is possible to compensate the driving TFT (DT) characteristic of the pixel in the display panel 100 based on this.

≪ Block Diagram of Organic Light Emitting Diode Display Apparatus According to Second Embodiment >

22 is a block diagram showing an organic light emitting diode display device according to a second embodiment of the present invention.

Referring to FIG. 22, the organic light emitting diode display device according to the second embodiment of the present invention may include a display panel 100, a gate driver 300, a data driver 200, and a timing controller 400.

개의 화소들을 구비할 수 있다.The display panel 100 includes m data lines DL1 to DLm, k sensing lines SEL1 to SLEk, n scan lines SL1 to SLn, and j Lt; RTI ID = 0.0 > SCL1 < / RTI >

Pixels.

Two adjacent pixels on the vertical line may share the sensing control lines SCL with each other.

Signal lines for supplying the first driving power source (Vdd) and signal lines for supplying the second driving power source (Vss) may be formed on the display panel (100). Here, the first driving power supply Vdd and the second driving power supply Vss may be generated from the high potential driving voltage source VDD and the low potential driving voltage source VSS, respectively.

The gate driver 300 generates a scan signal SS in response to a gate control signal GDC from the timing controller 400 and sequentially supplies the scan signal SS to the scan lines SL1 to SLn.

The gate driver 300 can also output a sensing control signal SCS controlled by the timing controller 400 and the sensing switch in each pixel can be controlled by the sensing control signal SCS.

The gate driver 300 outputs both the scan signal SS and the sensing control signal SCS but the present invention is not limited thereto and may be controlled by the timing controller 400 to output the sensing control signal SCS A sensing switch control driver may be provided.

The data driver 200 can be controlled by the data controller DDC from the timing controller 400 and can output the sensing voltage to the data lines DL1 to DLm and the sensing lines SEL1 to SELk have.

Each of the data lines DL1 to DLm may be connected to each pixel to apply a data voltage to each of the pixels.

Each of the sensing lines SEL1 to SELk may be connected to a pixel to supply a sensing voltage and measure a sensing voltage on the sensing lines SEL1 to SELk. Specifically, by supplying an initializing voltage using one sensing line (SEL1 to SELk), it is possible to detect a sensing voltage using charging and floating with the initializing voltage.

The data driver 200 may output or detect the data voltage and the sensing voltage. However, the present invention is not limited thereto, and may include a separate driver capable of outputting or detecting the sensing voltage.

The data driver 200 and the timing controller 400 can detect the Vth and k parameters of each of the driving TFTs DT of the pixels on the display panel 100 to compensate the characteristics of the driving TFT DT. At this time, the Vth and k parameters of the driving TFT DT are detected for only some of the pixels of the display panel 100 per frame, and are supplied to the data driver 200. The Vth and k parameters of the driving TFT DT of the remaining pixels Can be obtained by interpolation from the Vth and k parameters of the drive TFT DT detected.

That is, it is possible to sense the characteristics of the driving TFT DT for a pixel in a partial area of the display panel 100 during one frame, and to sense the remaining pixels during the next frame. For each pixel that is not sensed per frame, interpolation can be applied to the measured value from the sensed pixel to detect the threshold voltage and mobility.

The timing controller 400 may calculate the characteristic value of the driving TFT DT of the pixels not sensed by applying the interpolation method to the characteristic of the driving TFT DT of the sensed pixels supplied from the ADC 220, It is possible to compensate the driving TFT (DT) characteristic of the pixel in the display panel 100 based on this.

The organic light emitting diode display according to the first embodiment may include the pixel drive circuit according to the first embodiment, and the organic light emitting diode display according to the second embodiment may include the pixel drive according to the second embodiment, Circuit. As described above, the present invention can be implemented as a pixel driving circuit including a P-type transistor or a pixel driving circuit including an N-type transistor.

In this case, the transistor constituting the pixel driving circuit according to the first embodiment can be an LTPS transistor, and the LTPS transistor has a high mobility and a high current driving capability and can reduce a wiring width, There is an advantage that the deterioration of the device is small. The transistor constituting the pixel driving circuit according to the second embodiment can be an amorphous-Si transistor, and the amorphous silicon transistor has a small number of steps and a high yield. Therefore, the display panel 100 according to the embodiment of the present invention is applicable to any one of the display panels 100 including the pixel driving circuits according to the first and second embodiments in consideration of the manufacturing process, the yield, the current driving capability, It can be one.

<Vth and k parameter detection using interpolation>

&Lt; Vth and k parameter detection first method >

23 to 31 are diagrams showing the Vth and k parameter detection methods according to the embodiment of the present invention.

A method of using the interpolation method when detecting the Vth and k parameters of the display panel 100 including the pixel driving circuit described in the first and second embodiments will be described below.

According to the embodiment of the present invention, the Vth and k parameters of the driving TFT DT of some pixels in the display panel 100 are detected and the driving TFT DT of the adjacent pixel which is not sensed is connected to the driving TFT DT via the interpolation method. Vth and k parameters can be sensed.

Referring to FIG. 23, the scan lines SL are divided into an odd row line and an even row line, the pixels of the odd row line are sensed during the current frame, The pixels of the even row line can be sensed without sensing the pixels of the odd row line during the next frame. Specifically, the Vth and k parameters of the driver TFT DT of the pixel corresponding to the odd-numbered scan lines SL1, SL3, and SL5 are detected, and the driving TFTs of the pixels corresponding to the even-numbered scan lines SL2, SL4, The Vth and k parameters of the even numbered scan lines SL2, SL4, and SL5 are interpolated from the Vth and k parameters of the driver TFT DT of the pixels corresponding to the odd scan lines SL1, SL3, The Vth and k parameters of the driver TFT DT of the pixel corresponding to the pixels SL1 to SL6 can be obtained.

24, in the next frame, the Vth and k parameters of the driving TFT DT of the pixel corresponding to the even-numbered scan lines SL2, SL4 and SL6 are detected, and the scan lines SL1, SL3, The Vth and k parameters of the driver TFT DT of the corresponding pixel are set to the odd scan lines GL1 and GL2 from the Vth and k parameters of the driver TFT DT of the pixel corresponding to the even scan lines SL2, SL4, and SL6, Vth and k parameters of the driving TFT DT of the pixel corresponding to the pixels GL1, GL3, and GL5 can be obtained.

In this manner, the Vth and k parameters of the driving TFT DT of all pixels are actually detected once over two frames, and the Vth and k parameters of the driving TFT DT of all the pixels are detected approximately once .

On the other hand, when the Vth and k parameters are detected in an approximate manner, interpolation can be used. Interpolation is a method of determining two or more values of consecutive variables at intervals, determining a type of a function satisfying them, And the approximate calculation method of obtaining the value of the function with respect to the numerical value.

The interpolation method may be various types such as linear interpolation, polynomial interpolation, spline interpolation, and inverse distance weighting, but an average value can be used.

25, among the pixels corresponding to the nth, n + 1, and n + 2th scan lines that share the same data line DLm, the Vth of the driving TFT DT in the pixel on the n- Th scan line and the average value of the Vth and k parameters (Vth3, k3) of the drive TFT (DT) in the pixels on the (n + The Vth and k parameters (Vth2, k2) of the input signals DT and DT can be obtained.

In this way, the Vth and k parameters for the driving TFT DT in all the pixels are detected during one frame, and the characteristic detection of the driving TFT DT is started in the opposite manner during the next frame, . That is, by changing the pixels to be sensed every frame, it is possible to prevent the pixels to be sensed from being biased to one side while reducing the compensation time, thereby preventing the accuracy of the compensation from being lowered.

On the other hand, the scan lines SL are divided into an odd number and an even number line, that is, one odd numbered line and an even numbered line, but the present invention is not limited to this, and can be divided into two lines or three lines. For example, in the case of sensing for two lines, pixels corresponding to 1, 2, 5, 6, 9, 10 th scan lines are sensed during the current frame, and pixels not sensed are sensed by Vth and k parameters and the Vth and k parameters of the pixels that have not been sensed after sensing the pixels corresponding to the 3, 4, 7, 8, 11, 12 ... scan lines during the next frame can be obtained by interpolation .

<Vth and k parameter detection second method>

26, a plurality of data lines DL are divided into an odd column line and an even column line, a pixel of an odd column line is sensed during a current frame, The pixels of the column line are not sensed and the pixels of the even column line can be sensed without sensing the pixels of the odd column line during the next frame.

Specifically, the Vth and k parameters of the driving TFT DT connected to the odd-numbered data lines DL1, DL3, DL5, DL5 and DL7 are detected during the current frame, and the Vth and k parameters of the driving TFT DT are connected to the even-numbered data lines DL2, DL4 and DL6 The Vth and k parameters of the driving TFT DT can be obtained from the Vth and k parameters of the driving TFT DT connected to the odd-numbered data lines DL1, DL3, DL5, DL5 and DL7 by interpolation. 27, the Vth and k parameters of the driving TFT DT connected to the even-numbered data lines DL2, DL4 and DL6 are detected in the next frame and odd-numbered data lines DL1, DL3, DL5, DL5, The Vth and k parameters of the driving TFT DT connected to the even-numbered data lines DL1 to DL7 can be obtained from the Vth and k parameters of the driving TFT DT connected to the even-numbered data lines DL2, DL4 and DL6 by interpolation.

The interpolation method using the average value among the interpolation methods described above can be applied and the average value is advantageous in that the computation processing speed is reduced and the complexity of the circuit of the timing controller 400 can be reduced.

28, Vth (n) of the driving TFT DT in the pixels on the n-th data line among the pixels corresponding to the n, n + 1, and n + 2th data lines that share the same scan line SLn And the average value of the Vth and k parameters (Vth3, k3) of the driver TFT (DT) in the pixels on the (n + 1) th data line and the k-th parameter (Vth1, k1) The Vth and k parameters (Vth2, k2) of the input signals DT and DT can be obtained.

In this way, the Vth and k parameters for the driving TFT DT in all the pixels are detected during one frame, and the characteristic detection of the driving TFT DT is started in the opposite manner during the next frame, .

On the other hand, the data lines DL are divided into odd and even lines, that is, one column is divided into an odd column line and an even column line. However, the present invention is not limited to this and can be divided into two lines or three lines. For example, in the case of sensing for two lines, pixels corresponding to the 1, 2, 5, 6, 9, 10 ... data lines are sensed during the current frame, and the Vth and k parameters of the pixels that have not been sensed after sensing the pixels corresponding to the 3, 4, 7, 8, 11, 12, ..., data lines during the next frame can be obtained by interpolation .

&Lt; Third method of Vth and k parameter detection >

29 and 30, when a plurality of scan lines SL are divided into an odd and even row line and a plurality of data lines DL are divided into odd and even column lines, SL4 and SL5 in the pixels connected to the odd column lines DL1 to DL5 and the pixels connected to the odd column lines DL1 to DL5 and the driving TFTs in the pixels connected to the even column lines DL2 to DL6, SL4 and SL6 connected to the odd-numbered lines SL1, SL3 and SL5 and the even-numbered columns DL2, DL4 and DL6 during the next frame, ) And the Vth and k parameters for the driving TFT DT in the pixel connected to the odd-column lines DL1, DL3, DL5, and DL5.

In addition, the non-detection pixels for which the Vth and k parameters are not detected in the current frame and the non-detection pixels for which the Vth and k parameters are not detected in the next frame, The Vth and k parameters for the DT can be obtained, and an average value can be used as an example of the interpolation method.

Referring to Fig. 31, an average value may be obtained from the Vth and k parameters of adjacent pixels on the row line, or may be obtained from the Vth and k parameters of adjacent pixels on the column line.

In this manner, the pixels in the display panel 100 are divided into a detection pixel and a non-detection pixel, the Vth and k parameters of the driving TFT DT of the detection pixel are detected, and the Vth and k parameters of the driving TFT DT of the non- Can be obtained by interpolation, thereby reducing the time required to compensate the characteristics of the driving TFT DT.

Also, the detection pixel and the non-detection pixel may be periodically changed.

In the process of manufacturing the pixel driving circuit in the display panel 100, the uniformity of the electrode material formed on the display panel 100 greatly affects the characteristics of the driving TFT DT, and when the uniformity is high, The characteristics of the driving TFT DT in the driving TFTs are almost similar. Due to process characteristics, the adjacent region of the display panel 100 has a high uniformity and a low uniformity among the spaced regions. Therefore, even if the characteristics of the driving TFT DT in an arbitrary region are used as the characteristics of the driving TFT DT in the region adjacent to the corresponding region, the error can be regarded as insignificant, and the image quality can be improved while reducing the compensation time .

In addition, the characteristics of the driving TFT DT can be compensated when the organic light emitting diode display device is turned on and off. In the case of applying the embodiment of the present invention, on / off of the power supply of the organic light emitting diode display device By reducing the delay, it is possible to reduce the response time of the organic light emitting diode display to the on / off command.

In addition, in the case of real-time compensation in which compensation is performed while driving the organic light emitting diode display device, the compensation time can be reduced and the power consumption can be reduced accordingly.

In addition, although the characteristics of the driving TFT DT of half the pixels in the display panel 100 are compensated for during one frame, the present invention is not limited to this, It is possible to detect the characteristics of the driver TFT DT of one pixel and perform compensation after detecting the characteristics of the driver TFT DT of all the pixels over several frames.

In addition, there is an advantage that the inspection time can be reduced even in the inspection process in mass production of the product.

In particular, it is possible to prevent an increase in the compensation time due to a sharp increase in the number of pixels due to the enlargement of the display device.

On the other hand, the interpolation method can be used when the Vth and k parameters of the drive TFT DT of the non-detection pixel are acquired. However, the present invention is not limited to this, and a copy method may be used. In the case of using the copying method, there is an advantage that the complexity of the circuit necessary for data calculation according to the interpolation method can be reduced.

The copying method may be a method of copying the Vth and k parameters of the driving TFT DT in the sensed pixel to the Vth and the k-wavelength of the driving TFT DT in the adjacent pixels without being sensed.

The adjacent pixels may be characteristics of the driving TFT DT in the left, right, upper, lower, or diagonally sensed pixels.

In particular, in the case of a display panel having a high density of pixels per inch, the uniformity of the characteristics of the driving TFT DT in adjacent pixels becomes high, so that the error according to the copying method can be further reduced.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

100 display panel
200 data driver
210 DAC
220 ADC
230 Sampling / Holder
240 sensing circuit
250 ADC
260 memory
270 control unit
280 Initial voltage generator
290 Data signal output section
300 gate driver
400 timing controller

Claims (12)

A display panel including a plurality of scan lines and pixel driving circuits formed at intersections of the plurality of data lines and including driving transistors (hereinafter referred to as TFTs) for controlling the current flowing through the organic light emitting diodes and the organic light emitting diodes;
A data driver for driving some pixel driving circuits of the pixel driving circuits to sense the characteristics of driving TFTs of the pixel driving circuits of the certain pixel driving circuits through the data lines; And
And a timing controller that applies interpolation to the characteristics of the driving TFTs of each of the sensed pixel driving circuits to obtain the characteristics of the driving TFTs of the remaining pixel driving circuits. The method according to claim 1,
The characteristics of the driving TFTs of the pixel driving circuits connected to odd-numbered scan lines among the scan lines are sensed, and the characteristics of the driving TFTs of the pixel driving circuits connected to the even- And applying the interpolation method to the characteristics of the driving TFTs of the pixel driving circuits connected to odd-numbered scan lines. The method according to claim 1,
The characteristics of the driving TFTs of the pixel driving circuits connected to odd-numbered data lines of the data lines are sensed, and the characteristics of the driving TFTs of the pixel driving circuits connected to the even- And applying the interpolation method to the characteristics of the driving TFTs of the pixel driving circuits connected to odd-numbered data lines. The method according to claim 2 or 3,
Wherein the pixels for sensing the characteristics of the driving TFT and the pixels for obtaining the characteristics of the driving TFT by interpolation are alternately repeated every frame. 5. The method of claim 4,
Wherein a characteristic of the driving TFT of the pixel to which the interpolation method is applied is determined as an average value of the characteristics of the driving TFT of the pixel to which the interpolation method is applied and the characteristic sensed from the driving TFT of two adjacent pixels. 6. The method of claim 5,
Each of the pixel driving circuits
A first switching TFT controlled by a scan signal on a first scan line of the scan lines and connected between the data line and a first node, a first switching TFT controlled by a scan signal on a second scan line of the scan lines, And a second switching TFT connected between the first node and the second node, a storage capacitor connected between the first and second nodes, and a light emission control TFT controlled by the light emission control signal and connected between the high potential power supply and the first node and,
Wherein the driving TFT controls a current flowing in the organic light emitting diode according to a potential difference on the first and second nodes. And a driving transistor (hereinafter, driving TFT) which is formed at the intersection of the plurality of scan lines and the data lines, the sensing line, and the sensing control lines and controls the current flowing through the organic light emitting diode and the organic light emitting diode A display panel including a display panel;
A data driver which drives some pixel driving circuits of the pixel driving circuits and senses characteristics of driving TFTs of the pixel driving circuits through the sensing line; And
And a timing controller that applies interpolation to the characteristics of the driving TFTs of each of the sensed pixel driving circuits to obtain the characteristics of the driving TFTs of the remaining pixel driving circuits. 8. The method of claim 7,
The characteristics of the driving TFTs of the pixel driving circuits connected to odd-numbered scan lines among the scan lines are sensed, and the characteristics of the driving TFTs of the pixel driving circuits connected to the even- And applying the interpolation method to the characteristics of the driving TFTs of the pixel driving circuits connected to odd-numbered scan lines. 8. The method of claim 7,
The characteristics of the driving TFTs of the pixel driving circuits connected to odd-numbered data lines of the data lines are sensed, and the characteristics of the driving TFTs of the pixel driving circuits connected to the even- And applying the interpolation method to the characteristics of the driving TFTs of the pixel driving circuits connected to odd-numbered data lines. 10. The method according to claim 8 or 9,
Wherein the pixels for sensing the characteristics of the driving TFT and the pixels for obtaining the characteristics of the driving TFT by interpolation are alternately repeated every frame. 11. The method of claim 10,
Wherein a characteristic of the driving TFT of the pixel to which the interpolation method is applied is determined as an average value of the characteristics of the driving TFT of the pixel to which the interpolation method is applied and the characteristic sensed from the driving TFT of two adjacent pixels. 12. The method of claim 11,
Each of the pixel driving circuits
A switching TFT controlled by a scan signal on the scan line and connected between the data line and a first node, a sensing TFT controlled by a sensing control signal on the sensing control line and connected between the second node and the sensing line, 1 and a storage capacitor connected between the first and second nodes,
Wherein the driving TFT controls a current flowing in the organic light emitting diode according to a potential difference on the first and second nodes.

Images