KR20150002973A - Organic light emitting diode display device and method of driving the same - Google Patents

Abstract

The present invention relates to an organic light emitting diode display device capable of compensating feature deviation between pixels due to degradation by accurately and quickly sensing the feature of each pixel in a display period and a driving method thereof. The OLED display device according to the present invention includes a display panel which has a structure in which a plurality of horizontal lines and a plurality of sub pixels with different colors are repeatedly arranged in a horizontal direction, and a data driver which includes a sensing unit which senses the feature of each sub pixel according to a group by dividing each horizontal line to a plurality of groups composed of the sub pixels which have different colors and are spatially distributed.

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 (OLED) display device, and more particularly, to an organic light emitting diode display device and a driving method thereof that can quickly and accurately sense pixel characteristics without any restriction on a sensing period to compensate for a characteristic deviation between pixels due to deterioration .

OLED (Organic Light Emitting Diode) display devices are self-luminous devices that emit organic light-emitting layers by recombination of electrons and holes. They are expected to be a next generation display device because they have high luminance, low driving voltage and ultra thin film.

Each of the plurality of pixels constituting the OLED display device includes an OLED element composed of an organic light emitting layer between the anode and the cathode and a pixel driving circuit independently driving the OLED element. The pixel driving circuit mainly includes a switching thin film transistor (hereinafter referred to as TFT) and a capacitor and a driving TFT. The switching TFT charges the capacitor corresponding to the data signal in response to the scan pulse, and the driving TFT controls the magnitude of the current supplied to the OLED element according to the magnitude of the voltage charged in the capacitor to control the amount of light emitted from the OLED element . The amount of light emission of the OLED element is proportional to the current supplied from the driving TFT.

However, OLED display devices have a problem of luminance non-uniformity among pixels due to various reasons. For example, a characteristic deviation such as a threshold voltage (hereinafter referred to as Vth) and mobility of a driving TFT due to a process variation or the like, a deviation of a power supply voltage due to a line resistance depending on a pixel position, There arises a problem of luminance unevenness due to deterioration of a TFT or an OLED element or the like. In general, a characteristic deviation of an initial driving TFT generates spots or patterns on a screen, and a characteristic deviation due to deterioration of a driving TFT or an OLED element caused by driving the OLED element reduces the lifetime of the OLED display panel, .

To solve these problems, prior arts such as US 7,834,825 disclose an external data compensation method that senses the driving current of each pixel and compensates the input data according to the sensing result. However, the prior art uses a method of measuring the current flowing to the power supply line (VDD or VSS line) of the panel while lighting each pixel, so that when the resolution is increased, the current sensing time is shortened due to parasitic capacitors existing in parallel to the power supply line There is a problem in that high-speed sensing is difficult.

Accordingly, in the prior art patent, it is possible to sense and compensate for the characteristic deviation between the initial driving TFTs in the inspection process before shipment of the product. However, the deterioration deviation of the driving TFT generated while driving the OLED display device after shipment of the product, There is a problem that compensation is difficult.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the conventional problems, and it is an object of the present invention to provide an organic light emitting diode (OLED) display device capable of quickly and accurately sensing characteristics of each pixel during a display period, A display device and a driving method thereof are provided.

According to an aspect of the present invention, there is provided an OLED display comprising: a display panel having a structure in which a plurality of sub-pixels each having a plurality of different horizontal lines are repeatedly arranged in a horizontal direction; And a data driver having a sensing unit for dividing the horizontal lines into a plurality of groups of a plurality of sub-pixels spatially dispersed with different colors and sensing characteristics of each sub-pixel for each group.

Each of the horizontal lines includes a first group of 5n-4th (n is a natural number) subpixels, a second group of 5n-3th subpixels, and a 5n-2th subpixel The third group, the fourth group consisting of the (5n-1) th sub-pixels, and the fifth group consisting of the (5n) th sub-pixels.

When the data driver drives one group in each of the horizontal lines in the sensing mode, the remaining groups are driven in the display mode.

Wherein the sensing unit selects and senses one of the plurality of groups in response to a sensing channel selection signal from the outside, and the selection order of the plurality of groups by the sensing channel selection signal is at least one horizontal line or at least one frame unit, .

The OLED display according to the embodiment of the present invention generates the channel selection control signal and calculates the luminance reduced by the group driven in the sensing mode in each horizontal line to calculate the luminance correction value, A data processing unit for compensating the luminance of peripheral pixels with the correction value; Wherein the control unit supplies the input data from the data processing unit to the data driver and controls driving of the data driver, inputs the sensed data from the subpixels of the respective groups through the sensing unit, And a timing controller for compensating data to be supplied to the data driver based on the stored data compensation value.

Wherein the data processing unit calculates the luminance reduced by each group driven in the sensing mode in units of at least five pixels and distributes the calculated luminance value to peripheral pixels driven in the display mode in the at least five pixels, And calculates a luminance compensation value for each pixel.

Wherein the data processing unit analyzes the input data corresponding to the at least five pixels and maps the sensing data to the subpixels driven in the sensing mode among the at least five pixels, The subpixel positions of the input data are selectively changed and mapped.

The data processing unit distributes the average luminance value of two adjacent pixels in the at least five pixels to peripheral pixels driven in the display mode and applies the luminance correction value to each of the peripheral pixels.

The timing controller repeats the sensing of each subpixel through the sensing unit to calculate the data compensation value corresponding to each subpixel.

Each pixel is composed of R / W / G / B subpixels or R / G / B subpixels.

A method of driving an OLED display according to an exemplary embodiment of the present invention is a method for driving a display panel having a structure in which a plurality of subpixels each having a plurality of different colors are repeatedly arranged in a horizontal direction, Dividing into a plurality of groups of a plurality of subpixels spatially dispersed with different colors; And sensing the characteristics of each subpixel in each of the groups to be divided in each of the horizontal lines.

An OLED display and a driving method thereof according to the present invention divide each horizontal line HLi into a plurality of groups having different colors and spatially separated subpixels, When one of the groups is driven in the sensing mode, the remaining groups can be driven in the display mode.

Accordingly, the OLED display device and the driving method thereof according to the present invention can sense the characteristics of subpixels throughout the period of the vertical synchronizing signal (each frame) regardless of the display period, so that it is necessary to sense all the subpixels Can be remarkably shortened. Therefore, deterioration of subpixels can be compensated in real time by fast sensing of the entire subpixels, or more accurate sensing can be performed by repetitive sensing of the same subpixel to compensate for deterioration of subpixels

In addition, the OLED display and the driving method thereof according to the present invention can minimize degradation of image quality by compensating for the luminance reduced by the sub-pixels driven in the sensing mode through data modulation of peripheral pixels.

1 is a diagram schematically showing a method of sensing pixel characteristics of an OLED display according to the prior art related to the present invention.
2 is a diagram illustrating a method of sensing pixel characteristics of an OLED display according to an embodiment of the present invention.
FIGS. 3A through 3E are diagrams illustrating a sensing method using a sensing unit included in an OLED display according to an exemplary embodiment of the present invention.
4A and 4B are diagrams showing a comparison of the sensing range of the OLED display according to the prior art and the present invention.
FIGS. 5A and 5B are diagrams illustrating a method of compensating a reduced luminance by a sub-pixel sensed in an OLED display according to an embodiment of the present invention.
6 is a diagram illustrating the sensing sequence of the first to fifth groups according to the sensing channel selection signal in each horizontal line of the OLED display according to the embodiment of the present invention.
7 is a block diagram schematically showing a configuration of an OLED display device according to an embodiment of the present invention.
8 is a block diagram showing an internal configuration of the data processing unit shown in Fig.
FIG. 9 is a flowchart showing a data processing method of the data processing unit shown in FIG. 8 step by step.

Prior to description of the embodiments of the present invention, the prior art related to the present invention will be described first to facilitate understanding of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram briefly illustrating a method for sensing pixel characteristics of an OLED display according to the prior art related to the present invention.

Referring to FIG. 1, only a sensing method for one horizontal line (HLi, i is a natural number) among a plurality of horizontal lines constituting the OLED display panel is representatively shown. One horizontal line HLi has a structure in which pixels composed of red (R), white (W), green (G), and blue (B) are repeatedly arranged in the horizontal direction.

The sensing unit built in the data driver groups R / W / G / B subpixels of one horizontal line (HLi) by color to sense pixel characteristics for each R / W / G / B group.

For example, for a horizontal line HLi, an R group consisting of R subpixels is sequentially sensed in sub-pixel units in a first sensing period SP1, and in a second sensing period SP2, In the third sensing period SP3, the W group is sequentially sensed in subpixel units, the G group composed of G subpixels is sequentially sensed in units of subpixels in the third sensing period SP3, Are sequentially sensed in units of subpixels.

The color group selected in each sensing period SP is driven in the sensing mode, so that the luminance of the horizontal line to be sensed decreases. Therefore, each sensing period SP is limited to the non-display period except for the display period, that is, the blank period of the vertical synchronizing signal, so that the luminance decrease due to the sensing mode is not recognized to the viewer. Only the color group is sensed.

Accordingly, in order to sense all of the subpixels of one horizontal line HLi, four blank frames corresponding to the first through fourth sensing periods SP1 through SP4 are required, so that k (k is a natural number) In order to sense all the subpixels in an OLED display panel having a horizontal line, a blank period of k * 4 frames is required. For example, in OLED display panels with 1080 horizontal lines, a blank period of 1080 * 4 frames is required to sense all subpixels.

Therefore, OLED display devices according to prior arts require a considerably long time to sense all subpixels, so that it is difficult to compensate data in real time by sensing the characteristics of subpixels.

In order to solve the problems of the prior art, the present invention proposes an OLED display device and a driving method thereof that can quickly and accurately sense the characteristics of a subpixel in a display period without any restriction on a sensing period.

In addition, the present invention proposes an OLED display device and a driving method thereof that can compensate the brightness of adjacent pixels so that a decrease in luminance due to a sensing mode of a sub-pixel is not recognized to the user.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a view illustrating a method of sensing pixel characteristics of an OLED display according to an embodiment of the present invention. Referring to FIG.

Referring to FIG. 2, each horizontal line HLi repeatedly arranged with alternating R / W / G / B subpixels is divided into a plurality of groups and sensed, and each group has a color R / W / G / B subpixels are mixed, and when a group is driven in the sensing mode in each horizontal line HLi, the remaining groups can be simultaneously driven in the display mode.

Specifically, each horizontal line HLi is divided into first to fifth groups which are sensed according to a consecutive sensing channel selection signal SCS.

According to the sensing channel selection signal SCS, a first group consisting of 5n-4 (n is a natural number) subpixels, a second group consisting of 5n-3th subpixels, and 5n-2th subpixels A third group, a fourth group consisting of 5n-1 th subpixels, and a fifth group consisting of 5nth subpixels are sequentially or randomly selected and sensed. The subpixels included in each selected group are sequentially sensed.

Referring to FIG. 2, in a horizontal line HLi of the OLED display according to the present invention, in response to a sensing channel selection signal SCS [000], a first group of 5n-4th sub- / W2 / G3 / B4 ... G2 / B3 / R5 corresponding to the 5n-3th sub-pixels in the second group in response to the sensing channel selection signal SCS [001]. B2 / R4 / W5 < / RTI > corresponding to 5n-2 < th > subpixels in response to the sensing channel selection signal SCS [010] B1 / R3 / W4 / G5 corresponding to the 5n-1th sub-pixels in the fourth group in response to the sensing channel selection signal SCS [011] Pixels corresponding to the fifth group of 5n-th sub-pixels are sequentially sensed in response to the sensing channel selection signal SCS [100], and R2 / W3 / G4 / B5 ... And sequentially senses the characteristics of the subpixels. Accordingly, R / W / G / B subpixels are mixed in the group to be sensed.

When one of the groups is driven in the sensing mode in each horizontal line HLi, the remaining group can be driven in the display mode. Accordingly, the OLED display device of the present invention is not limited to the blank period (non-display period) of the vertical synchronizing signal, and the characteristics of the subpixel in the entire period of the vertical synchronizing signal (each frame) It is possible to remarkably shorten the period of time required for sensing the entire subpixel as compared with the above-described prior art. Therefore, deterioration of subpixels can be compensated in real time by fast sensing of the entire subpixels, or more accurate sensing can be performed by repetitive sensing of the same subpixel to compensate for deterioration of subpixels

FIGS. 3A through 3E are diagrams illustrating a sensing method using a sensing unit included in an OLED display according to an exemplary embodiment of the present invention.

3A to 3E, the OLED display of the present invention includes a display panel 10 and a sensing unit 40, and the sensing unit 40 is usually embedded in a data driver.

The sensing unit 40 includes an input channel selector 22 for selecting an input channel, an output channel selector 24 for selecting an output channel, a multiplexer for sequentially supplying output signals of the output channel selector 24 (Hereinafter referred to as MUX), and an analog-to-digital converter (hereinafter referred to as ADC) that converts an output signal from the MUX into digital data and outputs the digital data as sensed data.

The input channel selection unit 22 includes first to fifth switches SW1 to SW5 for selecting the first to fifth input channels in response to the sensing channel selection signal SCS.

The output channel selection unit 24 includes first to fifth sampling and hold groups SH1 to SH5 for selecting the output channels of the first to fifth groups in response to the sensing channel selection signal SCS do.

3A, in response to the channel selection signal SCS [000], the first switch SW1 group is selected in the input channel selection unit 22 and the first sampling < RTI ID = 0.0 & The hold (SH1) group is selected. The sensing signal SS is supplied to the 5n-4th data line DL5n-4 of the display panel 10 through the selected first switch SW1 group so that the first group SW1 in the horizontal line of the display panel 10 And the (5n-4) th sub-pixels are driven in the sensing mode. The OLED element does not emit light in the sub pixel driven in the sensing mode. The 5n-4th sub-pixels driven in the sensing mode output a signal reflecting the characteristics of each sub-pixel through the 5n-4th sensing line SL5n-4, and the output signal is supplied to the first sampling & And then sequentially outputted to the ADC through the MUX, converted into digital data by the ADC, and output as sensed data.

3B, in response to the channel selection signal SCS [001], the second switch SW2 group is selected in the input channel selection unit 22, the second sampling & The hold (SH2) group is selected. The sensing signal SS is supplied to the 5n-3th data line DL5n-3 of the display panel 10 through the selected second switch SW2 group so that the second group SW2 in one horizontal line of the display panel 10 And the (5n-3) th sub-pixels are driven in the sensing mode. The signals output from the 5n-3th sub-pixels driven in the sensing mode via the 5n-3th sensing line SL5n-3 are sampled and held by the second sampling and hold (SH2) group, And sequentially converted into digital data by the ADC and output as sensed data.

3C, in response to the channel selection signal SCS [010], the third switch SW3 group is selected in the input channel selection unit 22 and the third sampling < RTI ID = 0.0 & The hold (SH3) group is selected. The sensing signal SS is supplied to the (5n-2) th data line DL5n-2 of the display panel 10 through the selected third switch SW3 group so that the third group And the (5n-2) th sub-pixels are driven in the sensing mode. The signals output from the 5n-2th sub-pixels driven in the sensing mode via the 5n-2 th sensing line SL5n-2 are sampled and held by the third sampling and holding (SH3) group, And sequentially converted into digital data by the ADC and output as sensed data.

Referring to FIG. 3D, in response to the channel selection signal SCS [011], the fourth switch SW4 group is selected in the input channel selection unit 22, the fourth sampling & Hold (SH4) group is selected. The sensing signal SS is supplied to the 5n-1th data line DL5n-1 of the display panel 10 through the selected fourth switch SW4 group so that the fourth group SW4 in one horizontal line of the display panel 10 And the (5n-1) th sub-pixels are driven in the sensing mode. The signals output from the 5n-1th sub-pixels driven in the sensing mode via the 5n-1th sensing line SL5n-1 are sampled and held by the fourth sampling and hold (SH4) group, And sequentially converted into digital data by the ADC and output as sensed data.

3E, in response to the channel selection signal SCS [100], the fifth switch SW5 group is selected in the input channel selection unit 22, the fifth sampling & Hold (SH5) group is selected. The sensing signal SS is supplied to the 5n-th data line DL5n of the display panel 10 through the selected fifth switch SW5 group so that the 5n-th sub- Are driven in the sensing mode. The signals output from the 5n-th sub-pixels driven in the sensing mode via the 5n-th sensing line SL5n are sampled and held by the fifth sampling and hold (SH5) group and then sequentially supplied to the ADC through the MUX Output from the ADC, converted into digital data from the ADC, and output as sensed data.

Here, the sensing lines SL5n-4 to SL5n may be a reference line for supplying a reference voltage for driving each subpixel or a data line DL5n-4 to DL5n for supplying the sensing signal, It may be a separately provided sensing line.

In FIGS. 3A to 3E, the subpixels of the remaining groups except one group to be sensed in one horizontal line are supplied with the corresponding data signals through the data driver, and are driven in the display mode to emit light. Therefore, each horizontal line can be divided into a group driven in a sensing mode and a group driven in a display mode, and can be driven simultaneously.

4A and 4B are diagrams showing a comparison of the sensing range of the OLED display according to the prior art and the present invention.

Referring to FIG. 4A, the sensing period in the OLED display according to the prior art is limited to the blank period A of the vertical synchronization signal Vsync. Therefore, if the display panel has 1080 horizontal lines and is driven at a frequency of 120Hz, the time taken to sense the entire subpixel is "(1080 * 4 * A) / 120Hz" Is a sensing period of a group).

Referring to FIG. 4B, the OLED display according to the present invention is capable of sensing in the entire period (B) of the vertical synchronization signal (Vsync). Accordingly, if the display panel has 1080 horizontal lines and is driven at a frequency of 120Hz, the time taken to sense the entire subpixel is "(1080 * 5 * A) / (120Hz * B)" The number of groups, and A is the sensing period of one group), it is understood that 0.8 * B times shorter than the prior art of FIG. 4A.

FIGS. 5A and 5B are diagrams illustrating a method of compensating a reduced luminance by a sub-pixel sensed in an OLED display according to an embodiment of the present invention.

When the OLED display device of the present invention senses the characteristics of the subpixels by group independently of the display period, the luminance reduced according to the off of the subpixel to be sensed is compensated by modulating the data of the remaining pixels driven in the display mode .

Referring to FIG. 5A, when the 5n-4th subpixels of the five pixels P1 to P5 are driven in the sensing mode and turned off and the remaining subpixels are driven in the display mode, It can be seen that the luminance corresponding to one pixel is reduced as compared with the case where all of the pixels P1 to P5 are driven in the display mode. In order to compensate for the reduced luminance, the position of the subpixel to which each data is mapped is selectively changed, and the luminance compensation value is distributedly applied to the remaining four pixels driven in the display mode.

For example, the sensing data is mapped to each of the R / W / G / B subpixels corresponding to the group driven in the sensing mode in the five pixels P1 to P5, and the R / W / G / B data is mapped to W / G / B / R subpixels, respectively, by changing the positions of subpixels only in the R data. The R / W / G / B data of the fourth pixel P4 is mapped to the B / R / W / G subpixel by changing the subpixel position only in the B data. The R / W / G / B data of the fifth pixel P5 is directly mapped to each of the R / W / G / B subpixels.

The R / W / G / B data of the second and third pixels P2 and P3 must be redundantly mapped to the G / B / R / W subpixel of one pixel, W / G / B data corresponding to the luminance average value? Is calculated from the R / W / G / B data of the G / B / R / W subpixel. At this time, if the luminance average value alpha of the two pixels P2 and P3 is applied to only one of the four pixels driven in the display mode, the luminance average value? The luminance becomes insufficient.

Therefore, as shown in FIG. 5B, the luminance average value alpha of the two pixels P2 and P3 corresponding to the luminance reduction when driving in the sensing mode is divided into quarters, and the luminance average value alpha / (YP1, (YP2 + YP3) / 2, YP4, YP5) of the four pixels driven by the driving signal generator (not shown). Accordingly, even if the subpixels driven in the sensing mode are turned off, the luminance of the remaining subpixels driven in the display mode is compensated to minimize the image quality deterioration.

Also, since the OLED display according to the present invention can compensate the luminance reduced by the sub-pixels driven in the sensing mode by modulating the remaining pixels driven in the display mode, the sub-pixel group to be sensed is not emitted . In this case, more sensing time can be secured, and the OLED element of the corresponding subpixel is turned off during sensing, so that the lifetime of the OLED element can be extended.

6 is a diagram illustrating the sensing sequence of the first to fifth groups according to the sensing channel selection signal SCS in each horizontal line of the OLED display device according to the embodiment of the present invention.

Referring to FIG. 6, the first through fifth groups may be sequentially sensed according to a sensing channel selection signal SCS in each horizontal line. In this case, each time the respective groups are sensed, the subpixels of the corresponding group are turned off, so that the resolution of each horizontal line is reduced to 1/5, which is likely to be recognized by the user.

In order to prevent this, the OLED display according to the present invention dither the sensing sequence of the first through fifth groups at least on a horizontal line basis or / and at least one frame basis to randomly vary the sensing sequence. Accordingly, the subpixels driven in the sensing mode on one screen are spatially and randomly dispersed, thereby preventing the decrease in resolution from being recognized by the user.

7 is a block diagram schematically showing a configuration of an OLED display device according to an embodiment of the present invention.

7 includes a display panel 10, a data driver 30, a gate driver 40, a gamma voltage generator 50, a timing controller 60, and a data processor 70.

And selectively outputs the luminance to the timing controller 60 according to whether the input data from the outside of the data processing unit 70 corresponds to the sensing line or the sensing group. 8, the data processing unit 70 includes a data input unit 72, a sensing control unit 74, a buffer 75, a data mapping unit 76, a luminance correction unit 78, (80), and performs data processing according to the flowchart of the data processing method shown in Fig. Fig. 8 and Fig. 9 are described together.

The sensing control unit 74 generates a sensing line selection signal indicating a horizontal line to be sensed using predetermined dither information and a sensing channel selection signal indicating sub pixels of a group to be sensed in a horizontal line to be sensed, It is determined whether the input data corresponds to the horizontal line and the sub-pixel of the sensing group (S2, S6) using the line selection signal and the sensing channel selection signal. If it is determined that the input data does not correspond to the sensing horizontal line, the sensing control unit 74 outputs the input data to the data output unit 80 through the buffer 75 (S4). The buffer 75 serves to adjust the timing between the circuit blocks. If it is determined that the input data corresponds to the sensing horizontal line and the subpixel of the sensing group, the sensing controller 74 outputs the sensing data to the data mapping unit 76. The data mapping unit 76 supplies the sensing data And outputs it to the data output unit 80 (S7). On the other hand, if it is determined that the input data corresponds to the sensing horizontal line but the sensing group is not a subpixel, the sensing control unit 74 outputs the input data to the data mapping unit 76 and the luminance correction unit 78. The sensing control unit 74 also supplies a sensing line selection signal and a sensing channel selection signal to the timing controller 60. [

As described above with reference to FIGS. 5A and 5B, the data mapping unit 76 analyzes the data in units of five pixels, and for the sensing mode, the remaining four pixels excluding the four subpixels to which the sensing data is mapped, The position of the subpixel to which the input data is mapped is selectively changed to correspond to the subpixel (S8). Since the data of five pixels must be mapped to four pixels, data of two pixels is redundantly mapped to one pixel.

The luminance correcting unit 78 calculates the luminance average value from the data of two pixels which are mapped to one pixel in the data mapping unit 76 and divides the luminance average value into four equal parts to calculate the luminance correction value of each of the four pixels (S10). The luminance corrector 78 corrects the luminance of each pixel with the luminance correction value and outputs it to the data output unit 80 (S12). Since the RWGB data input from the outside is gradation data, the brightness corrector 78 converts the RWGB data into 2YCbCr data including the luminance component (Y) through the color space conversion, calculates the luminance average value and the luminance correction value , The brightness of each pixel is compensated with the calculated luminance correction value, and then the RWGB data whose luminance is compensated by inversely converting the color space is output to the data output unit 80. On the other hand, the luminance corrector 78 outputs the sensing data from the data mapping unit 76 to the data output unit 80 as it is.

The data output unit 80 outputs the output data from the buffer 75 and the luminance correction unit 78 to the timing controller 60 (S14).

The timing controller 60 generates and outputs a data control signal and a gate control signal for controlling the driving timings of the data driver 30 and the gate driver 40 by using a plurality of synchronous signals from the data processing unit 70 . The timing controller 60 outputs the input data from the data processing section 70 to the data driver 30. [

The timing controller 60 outputs the sensing channel selection signal to the data driver 30 in response to the sensing horizontal line selection signal from the data processing unit 70 so that the data driver 30 outputs the sensing channel selection signal Pixels of the sensing group and outputs the sensing result. The output signal (i.e., sensed data) of each subpixel sensed by the data driver 30 corresponds to a pixel current that varies depending on Vth, mobility, OLED characteristics, etc. of the driving TFT for determining the characteristics of each subpixel , The characteristics of each subpixel can be detected and compensated using the data sensed from each subpixel. To this end, the timing controller 60 includes a compensation value detection unit and a compensation unit.

The compensation value detection unit detects the compensation value for compensating the Vth and mobility deviation of the driving TFT according to each pixel current using the sensed data of each subpixel output from the data driver 30 and stores the compensation value in the memory. For example, as described in U.S. Patent No. 7,982,695, the compensation value detecting section detects a Vth and a mobility deviation of a TFT using a function of obtaining a pixel current according to Vth and mobility, and calculates an offset for compensating the detected Vth Value and a gain value for compensating for the mobility deviation are detected as a compensation value and stored in a memory in a look-up table form.

The compensation unit compensates the data input from the data processing unit 70 using the compensation value stored in the memory, and supplies the compensated data to the data driver 30. [ For example, the compensator compensates the input data by multiplying the gain value by the input data and adding the offset value to the input data.

The compensation value detection unit and the compensation unit may be incorporated in the timing controller 60, but may be provided as a separate circuit component between the timing controller 60 and the data driver 30.

The timing controller 60 determines the peak luminance according to the average picture level (APL) of the input data to reduce the power consumption, and supplies the peak luminance to the gamma voltage generator 50.

The gamma voltage generator 50 generates and supplies a gamma voltage set including a plurality of gamma voltages having different levels to the data driver 30. The gamma voltage generator 50 adjusts the maximum gamma voltage (gamma high potential power) corresponding to the peak luminance supplied from the timing controller 60, divides the adjusted maximum gamma voltage through the resistor string, And generates and outputs a gamma voltage set including the voltage.

The data driver 30 converts the digital data from the timing controller 60 into an analog data signal in response to the data control signal from the timing controller 60 and supplies the analog data signal to a plurality of data lines of the display panel 10. [ At this time, the data supply unit of the data driver 30 subdivides the gamma voltage set from the gamma voltage generator 50 into the gray scale voltages corresponding to the gray scale values of the data, and then uses the subdivided gray scale voltages to convert the digital data Into an analog data signal.

The data driver 30 further includes the sensing unit 20 described above with reference to FIGS. 3A to 3E. The sensing unit 20 divides each horizontal line HLi into five groups in response to a sensing channel selection signal SCS from the timing controller 60 and supplies sensing data to each of the subpixels for each of the divided groups After driving in the sensing mode, the characteristic of each sub-pixel is sensed and output to the timing controller 60. [

The gate driver 8 sequentially drives a plurality of gate lines of the display panel 10 in response to a gate control signal from the timing controller 2. [ The gate driver 8 supplies a gate-on voltage to the respective gate lines in response to the gate control signal and a gate-off voltage in the remaining period.

The display panel 10 has a pixel matrix in which R / W / G / B subpixels connected to a data line, a gate line, an ELVDD line and a low potential power supply (ELVSS) line are arranged in a matrix form . Each sub-pixel has an OLED element and a pixel circuit for driving the OLED element. The pixel circuit includes at least a switching transistor and a driving transistor and a storage capacitor. The switching transistor charges the storage capacitor with a voltage corresponding to the data signal from the data line in response to the scan pulse from the gate line. The driving transistor controls the current supplied to the OLED element according to the voltage charged in the storage capacitor, Adjust the amount of light emitted by the device. The amount of light emission of the OLED element is proportional to the current supplied from the driving transistor.

Although only the OLED display device having the R / W / G / B subpixel has been described in the above embodiments, the present invention is not limited thereto, and the present invention can be applied to the OLED display device having the R / G / B subpixel.

As described above, the OLED display according to the embodiment of the present invention and the driving method thereof divide each horizontal line HLi into a plurality of groups having different colors and spatially dispersed subpixels, By sensing the characteristics of the subpixels, the remaining group can be driven in the display mode when either group is driven in the sensing mode.

Accordingly, the OLED display device and the driving method thereof according to the present invention can sense the characteristics of subpixels throughout the period of the vertical synchronizing signal (each frame) regardless of the display period, so that it is necessary to sense all the subpixels Can be remarkably shortened. Therefore, deterioration of subpixels can be compensated in real time by fast sensing of the entire subpixels, or more accurate sensing can be performed by repetitive sensing of the same subpixel to compensate for deterioration of subpixels

In addition, the OLED display and the driving method thereof according to the present invention can minimize degradation of image quality by compensating for the luminance reduced by the sub-pixels driven in the sensing mode through data modulation of peripheral pixels.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, And the like. Accordingly, such modifications are deemed to be within the scope of the present invention, and the scope of the present invention should be determined by the following claims.

10: Display panel 20:
22: input channel selection unit 24: output channel selection unit
30: Data driver 40: Gate driver
50: gamma voltage generator 60: timing controller
70: data processing unit 72; Data input section
74: sensing control unit 75: buffer
76: Data mapping unit 78: Brightness correction unit
80: Data output section

Claims (18)

A display panel having a structure in which a plurality of sub-pixels each having a plurality of horizontal lines and having different colors are repeatedly arranged in a horizontal direction;
And a data driver including a sensing unit for dividing the horizontal lines into a plurality of groups each having a different color and spatially dispersed into a plurality of groups and sensing the characteristics of the subpixels for each group. An organic light emitting diode (OLED) display device. The method according to claim 1,
The sensing unit
Each of the horizontal lines includes a first group of 5n-4th (n is a natural number) subpixels, a second group of 5n-3th subpixels, a third group of 5n-2th subpixels, A fourth group of 5n-1 th sub-pixels, and a 5th group of 5n-th sub-pixels, and each group is divided into groups. The method according to claim 1,
The data driver
Wherein when driving one group in each of the horizontal lines in the sensing mode, the remaining groups are driven in the display mode. The method according to claim 1,
Wherein the sensing unit selects and senses one of the plurality of groups in response to a sensing channel selection signal from the outside,
Wherein the selection order of the plurality of groups by the sensing channel selection signal is randomly changed at least every one horizontal line or at least one frame unit. The method of claim 4,
And generates a luminance correction value by calculating the luminance reduced by the group driven in the sensing mode in each of the horizontal lines, generates data for compensating luminance of peripheral pixels by the luminance correction value, A processing unit;
Wherein the control unit supplies the input data from the data processing unit to the data driver and controls driving of the data driver, inputs the sensed data from the subpixels of the respective groups through the sensing unit, Wherein the OLED display further comprises a timing controller for calculating and storing a value and compensating data to be supplied to the data driver with the stored data compensation value. The method of claim 5,
The data processing unit
Wherein the control unit calculates the brightness reduced by each group driven by the sensing mode in units of at least five pixels and distributes the calculated brightness value to peripheral pixels driven in the display mode in the at least five pixels, And calculates a luminance compensation value. The method of claim 5,
The data processing unit
The method comprising: analyzing input data corresponding to the at least five pixels, mapping sensing data to subpixels driven in the sensing mode among the at least five pixels, and subpixels driven in the display mode And the pixel position is selectively changed and mapped. The method of claim 7,
The data processing unit
Wherein the luminance average value of the two adjacent pixels in the at least five pixels is distributed to neighboring pixels driven in the display mode and is applied as the luminance correction value of each of the neighboring pixels. The method according to claim 1,
Wherein the timing controller repeatedly senses the subpixels through the sensing unit to calculate the data compensation value corresponding to each of the subpixels. The method according to any one of claims 1 to 9,
Wherein each pixel comprises an R / W / G / B subpixel or an R / G / B subpixel. For a display panel having a structure in which a plurality of subpixels each having a plurality of horizontal lines repeatedly arranged in a horizontal direction, each of the horizontal lines is divided into a plurality of subpixels spatially dispersed with different colors Into a plurality of configured groups;
And sensing the characteristics of each subpixel for each group to be divided in each of the horizontal lines. The method of claim 11,
Each of the horizontal lines includes a first group of 5n-4th (n is a natural number) subpixels, a second group of 5n-3th subpixels, a third group of 5n-2th subpixels, A fourth group of 5n-1 th sub-pixels, and a fifth group of 5n-th sub-pixels. The method of claim 11,
Wherein when driving one group in each of the horizontal lines in the sensing mode, the remaining groups are driven in the display mode. The method of claim 11,
One of the plurality of groups is selected and sensed in response to a sensing channel selection signal from the outside,
Wherein the selection order of the plurality of groups by the sensing channel selection signal is randomly changed at least every one horizontal line or at least one frame unit. 15. The method of claim 14,
And generates a luminance correction value by calculating the luminance reduced by the group driven in the sensing mode in each of the horizontal lines, generates data for compensating luminance of peripheral pixels by the luminance correction value, Processing step;
Wherein the control unit supplies the input data from the data processing unit to the display panel through a data driver and inputs sensed data from the subpixels of each group through a sensing unit built in the data driver, Further comprising the step of compensating for data to be supplied to the data driver. 16. The method of claim 15,
The data processing step
Wherein the control unit calculates the brightness reduced by each group driven by the sensing mode in units of at least five pixels and distributes the calculated brightness value to peripheral pixels driven in the display mode in the at least five pixels, And calculating a luminance compensation value based on the luminance compensation value. 16. The method of claim 15,
The data processing step
The method comprising: analyzing input data corresponding to the at least five pixels, mapping sensing data to subpixels driven in the sensing mode among the at least five pixels, and subpixels driven in the display mode And selectively mapping and mapping the pixel positions. 18. The method of claim 17,
The data processing step
Wherein the luminance average value of two adjacent pixels in the at least five pixels is distributed to neighboring pixels driven in the display mode and is applied as a luminance correction value of each of the neighboring pixels.

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