KR102389198B1 - electroluminescent display device and sensing method thereof - Google Patents

Abstract

The present invention relates to an electroluminescent display and a sensing method thereof, wherein the electroluminescent display includes first and second subpixels of the same color, a first data line connected to the first subpixel, and the second subpixel a second data line connected to the , a gate line shared with the first and second sub-pixels, and a sensing line shared with the first and second sub-pixels. The first and second sub-pixels are simultaneously initialized and then sensed simultaneously in a first sensing period. Any one of the first and second sub-pixels is sensed in a second sensing period following the first sensing period.

Description

Electroluminescent display device and sensing method thereof

The present invention relates to an electroluminescent display device for modulating data to be written in pixels in order to compensate for deterioration of the pixels based on a result of sensing electrical characteristics of the pixels, and a sensing method thereof.

The electroluminescent display device is roughly classified into an inorganic light emitting display device and an organic light emitting display device according to the material of the light emitting layer. Among them, the active matrix type organic light emitting display device includes an organic light emitting diode (hereinafter referred to as "OLED"), which is a representative electroluminescent diode that emits light by itself, and has a response speed It has the advantages of fast speed, luminous efficiency, luminance and viewing angle.

OLED, which is a self-luminous device, includes an anode electrode and a cathode electrode, and an organic compound layer formed therebetween. 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 (Electron Injection layer, EIL). When a power voltage is applied to the anode and cathode electrodes, holes passing through the hole transport layer (HTL) and electrons passing through the electron transport layer (ETL) are moved to the light emitting layer (EML) to form excitons, and as a result, the light emitting layer (EML) is produces visible light.

The organic light emitting display device arranges pixels each including an OLED and a driving TFT (Thin Film Transistor) in a matrix form, and adjusts the luminance of an image implemented in the pixels according to the grayscale of the image data. The driving TFT controls the driving current flowing through the OLED according to the voltage applied between its gate electrode and the source electrode (hereinafter, referred to as “gate-source voltage”). The amount of light emitted and the luminance of the OLED are determined according to the driving current.

In general, when the driving TFT operates in the saturation region, the driving current Ids flowing between the drain-source of the driving TFT is expressed as follows.

Ids = 1/2*(μ*C*W/L)*(Vgs-Vth) ²

Here, μ denotes electron mobility, C denotes the capacitance of the gate insulating film, W denotes the channel width of the driving TFT, and L denotes the channel length of the driving TFT, respectively. And, Vgs represents the gate-source voltage of the driving TFT, and Vth represents the threshold voltage (or threshold voltage) of the driving TFT. Depending on the pixel structure, the gate-source voltage (Vgs) of the driving TFT may be the difference voltage between the data voltage and the reference voltage. Since the data voltage is an analog voltage corresponding to the gray level of the image data and the reference voltage is a fixed voltage, the gate-source voltage (Vgs) of the driving TFT is programmed (or set) according to the data voltage. The driving current Ids is determined according to the programmed gate-source voltage Vgs.

Electrical characteristics of the pixel, such as the threshold voltage (Vth) of the driving TFT, the electron mobility (μ) of the driving TFT, and the threshold voltage of the OLED, are factors that determine the driving current (Ids), so they are the same in all pixels. Should be. However, electrical characteristics may vary between pixels due to various causes, such as process variations and changes over time. This deviation in the electrical characteristics of the pixels causes a difference in the amount of current that drives the OLED, which leads to deterioration of image quality and shortened lifespan between pixels.

An internal compensation method and an external compensation method may be applied to compensate for the deviation in electrical characteristics of the driving TFT. The internal compensation method uses a gate-source voltage of the driving TFT that changes according to the electrical characteristics of the driving TFT to automatically compensate for a deviation in the electrical characteristics of the driving TFT between pixels in real time. The external compensation method compensates for variations in electrical characteristics of the driving TFTs between pixels by sensing a voltage of a pixel that changes according to electrical characteristics of the driving TFTs, and modulating input image data in an external circuit based on the sensed voltage.

In order for the external compensation method to precisely compensate for the deviation of the electrical characteristics of the pixels, it is necessary to accurately sense the pixels. However, when the driving frequency of the display device is increased and the resolution is increased, the time required to sense the pixels becomes insufficient, and the sensing time may become insufficient.

The present invention provides an electroluminescent display device capable of accurately sensing a change in electrical characteristics of a pixel by sufficiently securing a sensing time of a pixel, and a sensing method thereof.

The electroluminescent display device of the present invention includes first and second sub-pixels of the same color, a first data line connected to the first sub-pixel, a second data line connected to the second sub-pixel, and the first and second sub-pixels and a gate line shared by the sub-pixels, and a sensing line shared by the first and second sub-pixels. The first and second sub-pixels are simultaneously initialized and then sensed simultaneously in a first sensing period. Any one of the first and second sub-pixels is sensed in a second sensing period following the first sensing period.

The electroluminescent display supplies a voltage of a black gray scale to sub-pixels that are not sensed during the second sensing period.

The output voltage of the integrator connected to the sensing line reaches ΔV1 during the first sensing period, the output voltage of the integrator reaches ΔV2 during the second sensing period, and the sub-pixel sensed during the second sensing period is a second sub-pixel, when the voltage of the black gray scale is applied to the first sub-pixel during the second sensing period. The sensing data R2 Sensing Data of the second sub-pixel and the sensing data R1 Sensing Data of the first red sub-pixel R1 are as follows.

R2 Sensing Data = ΔV2

R1 Sensing Data = ΔV1 - ΔV2

In the sensing method of the electroluminescent display, the first and second sub-pixels are simultaneously initialized, and then the initialized first and second sub-pixels are simultaneously sensed in a first sensing period, and in a first sensing period. and then sensing any one of the first and second sub-pixels in a second sensing period.

According to the present invention, after the sub-pixels of the same color are simultaneously initialized, the sub-pixels are simultaneously sensed in the first sensing period, and then only one of the two sub-pixels is sensed in the second sensing period. Accordingly, according to the present invention, sub-pixels of the same color share an initialization period.

The display device of the present invention can sufficiently secure the sensing time of sub-pixels of the same color, and therefore, can sufficiently secure the sensing time of the pixels even when the driving frequency of the display device increases or the resolution of the display panel increases.

In the display device of the present invention, the number of data lines can be reduced because sub-pixels having different colors share data lines.

In the display device of the present invention, since neighboring sub-pixels share one sensing line, the number of sensing lines can be greatly reduced.

1 is a block diagram illustrating an electroluminescent display device according to an embodiment of the present invention.
2 is a circuit diagram schematically showing a sensing circuit.
3 is a circuit diagram illustrating in detail a sensing unit connected to a pixel circuit.
4 is a diagram illustrating a portion of a pixel array having a double rate driving (DRD) structure.
5 is a waveform diagram illustrating a method of driving a display panel in a normal driving mode of the display panel.
6 is a waveform diagram illustrating a method of driving the display panel shown in FIG. 4 in a sensing mode.
7 is a diagram illustrating a portion of a pixel array having a stripe structure.
8 is a waveform diagram illustrating a method of driving the display panel shown in FIG. 7 in a sensing mode.
9 is a waveform diagram illustrating a sensing method according to an embodiment of the present invention.
10A and 10B are diagrams illustrating examples in which sub-pixels of the same color are continuously charged in a sensing method according to an embodiment of the present invention.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be embodied in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the art to which the present invention pertains It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims.

The shapes, sizes, proportions, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of the present invention are illustrative and the present invention is not limited to the illustrated matters. Like reference numerals refer to like elements throughout. In addition, in describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. When 'including', 'having', 'consisting', etc. mentioned in this specification are used, other parts may be added unless 'only' is used. When a component is expressed in the singular, cases including the plural are included unless otherwise explicitly stated.

In interpreting the components, it is construed as including an error range even if there is no separate explicit description.

In the case of a description of the positional relationship, for example, when the positional relationship of two parts is described as 'on', 'on', 'on', 'next to', etc., 'right' Alternatively, one or more other parts may be positioned between two parts unless 'directly' is used.

The first, second, etc. may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one component from another. Accordingly, the first component mentioned below may be the second component within the spirit of the present invention.

Features of various embodiments of the present invention may be partially or wholly combined or combined with each other, technically various interlocking and driving are possible, and each embodiment may be implemented independently of each other or may be implemented together in a related relationship. there is.

In the present invention, the pixel circuit and the gate driver formed on the substrate of the display panel may be implemented as transistors of an n-type or p-type MOSFET (Metal Oxide Semiconductor Field Effect Transistor) structure. The transistor may be formed as a thin film transistor (TFT) on a substrate of the display panel. It should be noted that although an n-type transistor (NMOS) is exemplified in the following embodiments, the present invention is not limited thereto. A transistor is a three-electrode device including a gate, a source, and a drain. The source is an electrode that supplies a carrier to the transistor. In the transistor, carriers begin to flow from the source. The drain is an electrode through which carriers exit the transistor. That is, the flow of carriers in the MOSFET flows from the source to the drain. In the case of an n-type transistor (NMOS), since carriers are electrons, the source voltage has a voltage lower than the drain voltage so that electrons can flow from the source to the drain. In an n-type transistor, since electrons flow from the source to the drain, the current flows from the drain to the source. In the case of a p-type transistor (PMOS), since carriers are holes, the source voltage is higher than the drain voltage so that holes can flow from the source to the drain. In a p-type TFT, since holes flow from the source to the drain, the current flows from the source to the drain. It should be noted that the source and drain of the transistor are not fixed. For example, the source and drain of the transistor may be changed according to an applied voltage.

The transistor may be implemented as an amorphous silicon (A-Si) transistor, an oxide transistor including an oxide semiconductor channel, and an LTPS transistor including a low temperature polysilicon (LTPS) channel.

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following embodiments, the electroluminescent display will be mainly described with respect to the organic light emitting display including the organic light emitting material. However, it should be noted that the technical spirit of the present invention is not limited to an organic light emitting display device, and may be applied to an inorganic light emitting display device including an inorganic light emitting material. The inorganic light emitting display device may include, but is not limited to, a quantum dot display device.

1 and 2 , the electroluminescent display device of the present invention includes a display panel 10 , a drive integrated circuit (IC) 20 , a host system 100 , a memory 30 , and the like.

A screen that reproduces an input image on the display panel 10 includes a plurality of pixels P connected to signal lines. Each of the pixels P may include red (R), green (G), and blue (B) sub-pixels SP for color implementation. Each of the pixels may further include a white (W) sub-pixel SP in addition to the RGB sub-pixels. Each of the sub-pixels SP may be implemented as a pixel circuit as shown in FIG. 3 , but is not limited thereto.

The signal lines are the data lines 11 that supply the data signal Vdata to each of the sub-pixels SP and the data lines 11 that simultaneously supply the gate signal to the sub-pixels SP disposed on the same line in the display panel 10 . It may include gate lines 12 and sensing lines 13 connected to the sub-pixels SP. The gate signal may include two or more scan signals depending on the pixel circuit. The sensing lines 13 are used to sense electrical characteristics of the sub-pixels SP.

As in the pixel array shown in FIG. 4 , sub-pixels SP having different colors may be connected to each other by being connected to one data line 11 . Since sub-pixels SP having different colors are connected to one data line 11 and are time-division driven, the number of data lines 11 may be reduced to half compared to the pixel array shown in FIG. 8 .

In the pixel array of the present invention, sub-pixels SP disposed on a plurality of lines in the display panel may be connected to one data line as shown in FIG. 4 . The vertical neighboring sub-pixels SP and the left and right neighboring sub-pixels are connected to one sensing line 13 and are initialized in the sensing mode. ), the sub-pixels SP are sequentially sensed through the shared sensing line 13 . Accordingly, the present invention can significantly reduce the number of sensing lines 13 .

The pixels P of the display panel 10 are arranged in a matrix form to constitute a pixel array. Each of the sub-pixels SP may be connected to any one of the data lines 11 , any one of the sensing lines 13 , and at least one of the gate lines 12 . The sub-pixels SP are configured to receive the high-potential power supply voltage VDD and the low-potential power supply voltage VSS from a power generator (not shown). To this end, the power generator may supply the high potential power voltage VDD to the sub-pixels SP through the VDD line. The power generator may supply the low potential power voltage VSS to the sub-pixels SP through the VSS line.

The drive IC 20 includes a data driving circuit 22 , 23 , 26 , 27 that modulates the input image data with a compensation value selected based on the sensing result of each of the sub-pixels SP and generates a data voltage; The driving circuits 22 , 23 , 26 , and 27 and a timing control unit 21 for controlling the operation timing of the gate driving unit 15 are provided. The data driving circuits 25 , 26 , and 27 of the drive IC 20 add a preset compensation value to the input image data to generate compensation data, convert the compensation data into a data voltage, and supply the compensation data to the data lines 11 . do. The data driving circuits 25 , 26 , and 27 include a data driving unit 25 , a compensating unit 26 , a compensation memory 27 , and the like. The compensation memory 27 and the memory 30 may be implemented as one memory. The data driving unit 25 may include a sensing unit 22 and a data voltage generating unit 23 , but is not limited thereto.

The gate driver 15 generates a gate signal and sequentially supplies it to the gate lines 12 . The gate driver 15 may be directly formed on the substrate of the display panel 10 together with signal lines and TFTs of the pixel array. The gate driver 15 includes a shift register that sequentially outputs a gate signal in response to a gate timing control signal GDC input through a level shifter. The gate timing control signal includes a gate start pulse, an N-phase (N is an integer greater than or equal to 2) gate shift clock. The level shifter converts a transistor-transistor-logic (TTL) voltage level of the gate timing control signal GDC received from the timing controller 21 into a voltage capable of on/off switching of the TFT, that is, a gate high voltage and a gate low voltage. do.

The timing controller 21 may include timing signals from the image signal input from the host system 100 , for example, a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a dot clock signal DCLK, and a data enable signal DE). The gate timing control signal GDC for controlling the operation timing of the gate driver 15 and the data timing control signal DDC for controlling the operation timing of the data driver 25 may be generated based on the above information.

The data timing control signal DDC may include, but is not limited to, a source start pulse, a source sampling clock, and a source output enable signal. The source start pulse controls the data sampling start timing of the data voltage generator 23 . The source sampling clock is a clock signal that controls the sampling timing of data based on a rising or falling edge. The source output enable signal controls the output timing of the data voltage generator 23 .

The gate timing control signal GDC may include a gate start pulse, a gate shift clock, and the like, but is not limited thereto. A gate start pulse is applied to the stage that produces the first output to activate the operation of that stage. The gate shift clock is a clock signal for shifting the gate start pulse as a clock signal commonly input to the stages.

The data voltage generator 23 generates a data signal Vdata of an input image using a digital-to-analog converter (hereinafter referred to as a DAC) 23 and transmits the pixels through the data lines 11 . (P) is supplied.

In the sensing mode for measuring the electrical characteristic deviation of the pixel before product shipment or during product driving, the data voltage generator 23 generates a preset data voltage for sensing, and applies the sensing data voltage to the data lines 11 . is supplied to the sensing target pixels P of the display panel 10 through The data voltage for sensing may be determined by a grayscale-luminance measuring system (not shown). The grayscale-luminance measuring system senses the electrical characteristics of each of the sub-pixels SP, and based on the sensing result, a compensation value of the pixel compensating for the electrical characteristic deviation between the sub-pixels SP, in particular, the threshold voltage deviation of the driving TFT (Offset) is derived and the compensation value of the pixel is stored in the memory 30 or a previously stored value is updated. The memory 30 may be a flash memory, but is not limited thereto. The grayscale-luminance measuring system used in the sensing mode may be electrically connected to the memory 30 during the sensing mode operation. Since the red OLED, the green OLED, and the blue OLED have different luminous efficiencies, the sensing data voltage may be set differently for each color of the sub-pixel SP. The present invention simultaneously senses the first and second sub-pixels SP of the same color during the sensing time sharing the initialization time, so that the sensing time of the pixels can be sufficiently secured even when the driving frequency of the display device or the resolution is increased. there is.

When power is applied to the electroluminescent display device, the compensation value from the memory 30 is loaded into the internal compensation memory 27 of the drive IC 20 . The compensation memory 27 of the drive IC 20 may be a DDR SDRAM (Double Date Rate Synchronous Dynamic RAM) or SRAM, but is not limited thereto.

The sensing unit 22 may be configured to sense an electrical characteristic of each pixel, eg, a threshold voltage of the driving TFT, and transmit it to the grayscale-luminance measuring system in the aging process before product shipment. In the case of an application such as a television, the sensing unit 22 may sense the sub-pixels SP after the product is shipped, and may update the compensation value in real time according to the sensing result. However, the present invention is not limited to the application.

As shown in FIG. 2 , the sensing unit 22 includes an integrator INT connected to the sensing line 13 , a sample and hold circuit SH connected to an output terminal of the integrator INT, and a sample and hold circuit SH. An analog-to-digital converter (Analog to Digital Converter, hereinafter referred to as "ADC") is included in the output terminal of the . The sensing unit 22 converts the voltage Vsen received from the pixel circuit into digital data and outputs sensing data S-DATA.

The integrator INT accumulates charges received from the sub-pixel SP through the sensing line 13 in the integrator INT. The sample and hold circuit SH samples the output voltage of the integrator INT. The ADC converts the analog sensing voltage supplied from the sample and hold circuit SH into digital data and outputs digital sensing data S-DATA. The sensing unit 22 is not limited to FIGS. 2 and 2 . For example, the sensing unit 22 may be implemented as a known voltage sensing circuit or a current sensing circuit.

The compensator 26 modulates the data V-DATA of the input image with the compensation value read from the compensation memory 27 and transmits it to the data voltage generating unit 23 . The compensation unit 26 may update the compensation value according to the sensing data S-DATA received from the sensing unit 22 .

The host system 100 may be any one of a television system, a set-top box, a navigation system, a personal computer (PC), a home theater system, a mobile system, a wearable system, and a virtual reality system (VR). . The example of FIG. 1 illustrates a mobile system configuration. The configuration of the driving circuit of the display panel may vary according to the host system 100 . The host system 100 may be implemented as an application processor (AP) in a mobile system, a wearable system, a virtual reality system, and the like.

3 is a circuit diagram illustrating in detail a sensing unit connected to a pixel circuit.

Referring to FIG. 3 , the pixel circuit includes an OLED, a driving TFT (DT), a capacitor (Cst), first and second switch TFTs (S1, S2), and the like.

The pixel circuit is supplied with a high potential power supply voltage VDD and a low potential power supply voltage VSS. The drive I 20 supplies the data signal Vdata to the pixel circuit. The gate driver 15 supplies the first and second scan signals SCAN1 and SCAN2 to the pixel circuit.

OLED is a light emitting element in a pixel circuit. The OLED includes an organic compound layer formed between an anode and a cathode. The organic compound layer may include, but is not limited to, a hole injection layer (HIL), a hole transport layer (HTL), a light emitting layer (EML), an electron transport layer (ETL), and an electron injection layer (EIL). The cathode CAT of the OLED is connected to the low potential power voltage VSS, and the anode ANO is connected to the source of the driving TFT DT.

The driving TFT (DT) is a driving element that controls the current flowing through the OLED according to the gate-source voltage (Vgs). The driving TFT (DT) has a gate connected to the first switch TFT (S1) and the capacitor (Cst), a source connected to the anode of the OLED and the second switch TFT (S2), and a drain to which the high potential power supply voltage (VDD) is supplied. include The capacitor Cst is connected between the gate and the source of the driving TFT DT.

The first switch TFT S1 is turned on in response to the first scan signal SCAN1 to transmit the data signal from the data line 11 to the gate and the capacitor Cst of the driving TFT DT. supply The first switch TFT S1 includes a gate connected to the first gate line 121 to which the first scan signal SCAN1 is applied, a source connected to the data line 11 to which the data signal Vdata is applied, and a driving TFT ( DT) and a drain connected to the capacitor Cst.

The second switch TFT S2 is turned on in response to the second scan signal SCAN2 to connect the source of the driving TFT DT to the sensing line 13 . The second switch TFT S2 is connected to the gate connected to the second gate line 122 to which the second scan signal SCAN2 is applied, the source of the driving TFT DT and the source connected to the anode of the OLED, and the sensing line 13 . It includes a connected drain.

When the pixel circuit is initialized, a predetermined reference voltage Vref is applied from the integrator INT to the sensing line 13 . The reference voltage Vref is lower than the high potential power voltage VDD and is set to a voltage at which the OLED does not emit light.

The integrator INT is between the operational amplifier AMP, the first switch element SW1 connected to the non-inverting input terminal (+) of the operational amplifier AMP, and the inverting input terminal (-) and the output terminal of the operational amplifier AMP and a capacitor Cint and a second switch SW2 connected to the . The capacitor C13 is connected to the inverting input terminal of the operational amplifier AMP, and the sample and hold circuit SH is connected to the output terminal of the operational amplifier AMP. The integrator INT accumulates charges from the pixel circuit input through the sensing line 13 and supplies it to the sample and hold circuit SH.

The first switch element SW1 is connected between the non-transformed terminal (+) of the operational amplifier AMP and the first reference voltage source. The first reference voltage source generates a reference voltage Vref. It is turned on during the initialization period and the sensing period of the pixel circuit to supply the reference voltage Vref to the non-inverting terminal (+) of the operational amplifier AMP. In the initialization period of the pixel circuit, the second switch TFT S2 is turned on. Accordingly, when the reference voltage Vref is applied to the non-inverting terminal (+) of the operational amplifier AMP, the reference voltage Vref is applied to the driving TFT in the pixel circuit through the sensing line 13 and the second switch TFT S2. The source of (DT), the capacitor (Cst), and the anode voltage of the OLED are initialized to the reference voltage (Vref).

The second switch element SW2 is turned on in response to the initialization timing signal INIT_CI. When the second switch element SW2 is turned on, the inverting input terminal (-) and the output terminal of the operational amplifier AMP are short-circuited to initialize the voltage of the capacitor Cfb.

The sample and hold circuit SH includes a third switch element SW3 , a sampling capacitor Csam and a fourth switch SW4 . The sampling capacitor Csam is connected between the node between the third switch element SW3 and the fourth switch element SW4 and the second reference voltage source. The second reference voltage source generates a second reference voltage Vref2. The second reference voltage Vref2 may be set to be the same as or different from the reference voltage Vref.

The third switch element SW3 is turned on in response to the sampling timing signal SAM. The third switch element SW3 and the fourth switch element SW4 are alternately turned on. When the third switch element SW3 is turned on and the fourth switch element SW4 is turned off, the output voltage Vout of the integrator INT is applied to the sampling capacitor Csam to output the integrator INT. The voltage Vout is sampled.

The fourth switch element SW4 supplies the voltage sampled by the sample and holder circuit SH to the ADC. The ADC converts the voltage input through the fourth switch element SW into digital data and transmits it to the drive IC 20 .

In the display device of the present invention, the first and second sub-pixels of the same color are connected to different data lines 11 as shown in FIGS. 4 and 7 . It shares a sensing line. These sub-pixels share an initialization period in sensing mode, as described in the embodiment below.

4 is a diagram illustrating a portion of a pixel array having a double rate driving (DRD) structure. 5 is a waveform diagram illustrating a method of driving the display panel shown in FIG. 4 in a normal driving mode of the display panel. 6 is a waveform diagram illustrating a method of driving the display panel shown in FIG. 4 in a sensing mode. 4 to 6 , “D1 to D4” denote data lines 11 , and “G1 to G4” denote gate lines 12 . “R1 to R4” denote a red sub-pixel, “G1 to G4” denote a green sub-pixel, and “B1 to B4” denote a blue sub-pixel, respectively. "W1 to W4" represent white sub-pixels.

4 to 6 , a plurality of sub-pixels SP having different colors are connected to one data line D1 to D4 in the display panel 10 . The red sub-pixels R1 and R3 and the blue sub-pixels B1 and B3 are connected to the first data line D1. The green sub-pixels G1 and G3 and the white sub-pixels W1 and W3 are connected to the second data line D2 .

The red sub-pixels R2 and R4 and the blue sub-pixels B2 and B4 are connected to the third data line D3. The green sub-pixels G2 and G4 and the white sub-pixels W2 and W4 are connected to the fourth data line D4 .

As in the pixel array shown in FIG. 4 , sub-pixels having different colors may be connected to each other by being connected to one data line D1 to D4 . Since sub-pixels having different colors are connected to one data line D1 to D4 and time-division driven, the number of data lines may be reduced to 1/2 compared to the pixel array shown in FIG. 7 .

In the pixel array shown in FIG. 4 , sub-pixels adjacent to the top and bottom and sub-pixels adjacent to the left and right are connected to one sensing line 13 . In the sensing mode, a plurality of sub-pixels sharing the sensing line 13 are sequentially sensed. In the present invention, sub-pixels of the same color sharing a sensing line are simultaneously initialized and then the sub-pixels are sequentially sensed. Accordingly, according to the present invention, the number of sensing lines 13 can be greatly reduced and the sensing time of the sub-pixels can be sufficiently secured.

Signals as shown in FIG. 5 are supplied to sub-pixels of the display panel 10 in a normal driving mode in which an input image is displayed on the screen of the display panel 10 . In the normal driving mode, the data signal Vdata of the input image is supplied to the data lines D1 to D4, and the scan signal synchronized with the data signal Vdata is sequentially supplied to the gate lines G1 to G4. The driver IC 20 supplies the data signal Vdata of the red and blue sub-pixels R1 to R4 and B1 to B4 to the first and third data lines D1 and D3, and the green and white sub-pixels The data signal Vdata of (G1 to G4, W1 to W4) is supplied to the second and fourth data lines D2 and D4. Scan signals sequentially shifted by the gate driver 15 may partially overlap. The scan signal may be the first and second scan signals SCAN1 and SCAN2 illustrated in FIG. 3 .

In the sensing mode, signals as shown in FIG. 6 are supplied to the sub-pixels of the display panel 10 . In the sensing driving mode, a sensing data signal Vdata is supplied to the data lines D1 to D4 , and a scan signal synchronized with the data signal Vdata is sequentially supplied to the gate lines G1 to G4 . In the sensing mode, the scan signals do not overlap each other as shown in FIG. 6 so that each of the lines of the display panel can be independently sensed. The scan signal may be the first and second scan signals SCAN1 and SCAN2 illustrated in FIG. 3 .

7 is a diagram illustrating a portion of a pixel array having a stripe structure. 8 is a waveform diagram illustrating a method of driving the display panel shown in FIG. 7 in a sensing mode.

7 and 8 , sub-pixels SP of the same color are connected to one data line D1 to D4 in the display panel 10 . The red sub-pixels R1 to R4 are connected to the first data line D1 . The white sub-pixels W1 to W4 are connected to the second data line D2 . The green sub-pixels G1 to G4 are connected to the third data line D3. The blue sub-pixels B1 to B4 are connected to the fourth data line D4 .

In the pixel array shown in FIG. 7 , the sub-pixels adjacent to the top and bottom and the sub-pixels adjacent to the left and right are connected to one sensing line 13 . In the sensing mode, a plurality of sub-pixels sharing the sensing line 13 are sequentially sensed. In the present invention, sub-pixels of the same color sharing a sensing line are simultaneously initialized and then the sub-pixels are sequentially sensed. Accordingly, according to the present invention, the number of sensing lines 13 can be greatly reduced and the sensing time of the sub-pixels can be sufficiently secured.

In the normal driving mode, the data signal Vdata and the scan signal of the input image are supplied to the sub-pixels of the display panel 10 . The scan signals may overlap as shown in FIG. 6 .

In the sensing mode, signals as shown in FIG. 8 are supplied to the sub-pixels of the display panel 10 . In the sensing driving mode, a sensing data signal Vdata is supplied to the data lines D1 to D4 , and a scan signal synchronized with the data signal Vdata is sequentially supplied to the gate lines G1 to G4 . In the sensing mode, the scan signals do not overlap each other as shown in FIG. 8 so that each of the lines of the display panel can be independently sensed. The scan signal may be the first and second scan signals SCAN1 and SCAN2 illustrated in FIG. 3 .

9 is a waveform diagram illustrating a sensing method according to an embodiment of the present invention. 10A and 10B are diagrams illustrating an example in which sub-pixels of the same color are continuously charged in a sensing method according to an embodiment of the present invention.

9 to 10B , the sensing method of the present invention initializes the sub-pixels R1 and R2 of the same color during the initialization period INI. During the initialization period INI, the scan signal SCAN is generated as a gate-on voltage. The gate-on voltage is set to a voltage at which the TFT can be turned on. In the sub-pixels R1 and R2 of the same color, the second switch TFT S2 is turned on in response to the scan signal SCAN. In this case, the sub-pixels R1 and R2 are connected to the integrator INT through the second switch TFT S2 and the sensing line 13 . In the initialization period INI, the integrator INT is activated and is initialized by the initialization timing signal INIT_CI. The first switch element SW1 is turned on to initialize the source voltage of the driving TFT DT and the anode voltage of the OLED in the sensing line 13 and the pixel circuit as the reference voltage Vref. During the initialization period INI, since the sub-pixels R1 and R2 of the same color are simultaneously initialized, the sub-pixels R1 and R2 share the initialization period INI.

During the first sensing period SENS1, the data signal Vdata of the same color is simultaneously applied to the sub-pixels R1 and R2 of the same color through the first and third data lines D1 and D3, and the data signals are sensed at the same time. . During the first sensing period SENS1 , the scan signal SCAN applied to the gate line G1 connected to the sub-pixels R1 and R2 is maintained as a gate-on voltage. In the sub-pixels R1 and R2 of the same color, the second switch TFT S2 maintains an on state. During the first and second sensing periods SENS1 and SENS2 , the initialization timing signal INIT_CI is deactivated. The integrator INT accumulates charges input from the sub-pixels R1 and R2 in the first sensing period SENS1 . The output voltage Vout of the integrator INT reaches ΔV1 in the first sensing period SENS1. ΔV1 is the sum of voltages representing electrical characteristics of each of the sub-pixels R1 and R2.

During the second sensing period SENS2, only one of the sub-pixels R1 and R2 of the same color is sensed. 9 to 10B are examples in which the second red sub-pixel R2 is sensed during the second sensing period SENS2. During the second sensing period SENS2, the scan signal SCAN is maintained at the gate-on voltage. In the second red sub-pixel R2 sensed in the second sensing period SENS2 , the second switch TFT S2 maintains an on state. The integrator INT accumulates charges input from the second red sub-pixel R2 in the second sensing period SENS2 . The output voltage Vout of the integrator INT reaches ΔV2 in the second sensing period SENS2. ΔV2 is a voltage indicating electrical characteristics of the second red sub-pixel R2 sensed in the second sensing period SENS2 . In the second sensing period SENS2 , the data voltage BLACK of the black gray scale is applied to the first red sub-pixel R2 that is not sensed, and the driving TFT DT is turned off in the first red sub-pixel R2 . No current flows through the OLED. Accordingly, only one of the sub-pixels R1 and R2 of the same color is sensed in the second sensing period SENS2. The drive IC 20 generates a preset black gradation voltage in the register regardless of the data voltage of the input image in the second sensing period SENS2, and the data line D1 connected to the first red sub-pixel R1 ) is supplied with a black gradation voltage.

The sensing data R2 of the second red sub-pixel R2 and the sensing data R1 of the first red sub-pixel R1 obtained by the sensing method shown in FIGS. 9 to 10B are as follows.

R2 Sensing Data = ΔV2

R1 Sensing Data = ΔV1 - ΔV2

9 to 10B illustrate examples of red sub-pixels, but the present invention is not limited thereto. The sensing method shown in FIGS. 9A to 10 is also applied to sub-pixels of a color other than red.

Those skilled in the art from the above description will be able to see that various changes and modifications are possible without departing from the technical spirit of the present invention. Accordingly, 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.

10: display panel 20: drive IC
22: sensing unit 23: data voltage generating unit
INT : Integrator SH : Sample and hold circuit
S1, S2: Switch TFT of pixel circuit DT: Driving TFT of pixel circuit

Claims (8)

first and second sub-pixels of the same color;
a first data line connected to the first sub-pixel;
a second data line connected to the second sub-pixel;
a gate line shared by the first and second sub-pixels; and
a sensing line shared by the first and second sub-pixels;
The first and second sub-pixels are simultaneously initialized and then sensed simultaneously in a first sensing period;
An electroluminescent display device in which any one of the first and second sub-pixels is sensed in a second sensing period following a first sensing period. The method of claim 1,
An electroluminescence display for supplying a voltage of a black gray scale to sub-pixels that are not sensed during the second sensing period. 3. The method of claim 2,
The output voltage of the integrator connected to the sensing line reaches ΔV1 during the first sensing period, the output voltage of the integrator reaches ΔV2 during the second sensing period, and the sub-pixel sensed during the second sensing period is a second sub-pixel, when the voltage of the black gray scale is applied to the first sub-pixel during the second sensing period.
The sensing data R2 Sensing Data of the second sub-pixel and the sensing data R1 Sensing Data of the first red sub-pixel R1 are
R2 Sensing Data = ΔV2
R1 Sensing Data = ΔV1 - ΔV2
phosphorous electroluminescent display. first and second sub-pixels of the same color;
a data line connected to the first and second sub-pixels; and
a sensing line shared by the first and second sub-pixels;
After the first and second sub-pixels are simultaneously initialized, they are sensed in a first sensing period;
An electroluminescent display device in which any one of the first and second sub-pixels is sensed in a second sensing period following a first sensing period. first and second sub-pixels of the same color, a first data line coupled to the first sub-pixel, a second data line coupled to the second sub-pixel, and a gate line shared to the first and second sub-pixels and a sensing method for an electroluminescent display including a sensing line shared by the first and second sub-pixels,
after simultaneously initializing the first and second sub-pixels, simultaneously sensing the initialized first and second sub-pixels during a first sensing period; and
and sensing any one of the first and second sub-pixels in a second sensing period following the first sensing period. 6. The method of claim 5,
A sensing method of an electroluminescent display for supplying a voltage of a black gray scale to sub-pixels that are not sensed during the second sensing period. 7. The method of claim 6
The output voltage of the integrator connected to the sensing line reaches ΔV1 during the first sensing period, the output voltage of the integrator reaches ΔV2 during the second sensing period, and the sub-pixel sensed during the second sensing period is a second sub-pixel, when the voltage of the black gray scale is applied to the first sub-pixel during the second sensing period.
The sensing data R2 Sensing Data of the second sub-pixel and the sensing data R1 Sensing Data of the first red sub-pixel R1 are
R2 Sensing Data = ΔV2
R1 Sensing Data = Sensing method of an electroluminescent display with ΔV1 - ΔV2. A sensing method for an electroluminescent display including first and second sub-pixels of the same color, a data line connected to the first and second sub-pixels, and a sensing line shared by the first and second sub-pixels In
after simultaneously initializing the first and second sub-pixels, sensing the initialized first and second sub-pixels in a first sensing period; and
and sensing any one of the first and second sub-pixels in a second sensing period following the first sensing period.

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