KR20190081809A - Tiled display and luminance compensation method thereof - Google Patents

Abstract

The present invention relates to a tiled display and compensating method thereof. The tiled display calculates a first degradation measurement value representing a degradation level of a first display panel based on a result sensing the degradation of the first display panel and calculates a second degradation measurement value representing a degradation level of a second display panel based on a result sensing the degradation of the second display panel. A target luminance defining the maximum luminance of the first and second display panels is selected according to a larger degradation measurement value among the first and second degradation measurement values. The tiled display of the preset invention may implement the uniform image quality without the luminance difference between the display panels.

Description

[0001] TILED DISPLAY AND LUMINANCE COMPENSATION METHOD THEREOF [0002]

The present invention relates to a tiled display that realizes a large screen using a plurality of display panels and a luminance compensation method thereof.

Digital Signage reproduces visual information from a commercial space to a large screen. Digital signage is a large-screen display known as multi-vision or video wall using tiled displays.

The tiled display includes a plurality of display panels bonded to a large surface. In order to improve the quality of the digital signage, the bezel of the display panels should be minimized so that the boundary between the display panels is minimized, and there should be no image quality difference between the display panels. Since digital signage can be installed outdoors, it requires reliability of a display panel suitable for a harsh outside environment and requires a high luminance to provide a clear screen even in the sunlight.

Even if the display panels constituting the tiled display have the same luminance characteristics at the time of shipment, differences in the degree of deterioration between display panels due to input image difference between the display panels and ambient temperature difference may occur. The difference in the degree of deterioration between the display panels results in a luminance difference between the display panels. The display panel may be replaced if any one of the display panels constituting the tiled display fails or reaches its end of life. In this case, a luminance difference may occur between the display panel with much deterioration and the new display panel with replacement.

Accordingly, the present invention provides a tiled display capable of automatically compensating for a luminance difference between display panels and a luminance compensation method thereof.

The tiled display of the present invention includes a first display panel driving unit for driving a first display panel, a second display panel driving unit for compensating pixel data to be written to pixels of the first display panel based on a result of sensing deterioration of the first display panel A first deterioration compensating unit, and a second display panel driving unit for driving the second display panel. And a second deterioration compensating unit compensating for pixel data to be written to the pixels of the second display panel based on a result of sensing deterioration of the first display panel.

The first deterioration compensator calculates a first deterioration measurement value representing a deterioration level of the first display panel and transmits the first deterioration measurement value to the second deterioration compensator. The second deterioration compensator calculates a second deterioration measurement value representing the deterioration level of the second display panel and transmits the second deterioration measurement value to the first deterioration compensator.

The luminance compensation method of the tiled display may include calculating a first deterioration measurement value representing a deterioration level of the first display panel based on a result of sensing deterioration of the first display panel, Calculating a second deterioration measurement value representative of a deterioration level of the second display panel based on a result of the sensing, selecting a larger deterioration measurement value among the first and second deterioration measurement values, And selects the target luminance that defines the maximum luminance of the first and second display panels according to the selected degradation measurement value.

The present invention shares the degradation measurement value (DM) of the display panels between degradation compensation units of each of the display panels driving the tiled display, and limits the maximum luminance of the display panels based on the largest degradation measurement value. As a result, the tiled display of the present invention can realize a uniform image quality without luminance difference between display panels.

1 is a diagram schematically showing a tiled display screen according to an embodiment of the present invention.
2 is a view showing the rear surface of the tiled display.
3 is a block diagram showing a display panel and a display panel driving unit.
4 is a circuit diagram showing the deterioration compensating unit.
5A and 5B are circuit diagrams showing details of an example of a pixel circuit and a deterioration compensating unit.
6 is a detailed block diagram of the compensation unit.
7 is a view showing a compensation look-up table.
8 is a view showing a luminance lookup table.
9 is a diagram showing an example in which a deterioration measurement value is shared between timing controllers.
FIG. 10 is a view showing an example in which the deterioration measurement values of the display panels in the integrated control box of the tiled display are compared and the target brightness is selected.
11 is a diagram illustrating an example in which the degradation measurement values are compared in each of the timing controllers mounted on the control boards of the tiled display to select the target brightness.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims and their equivalents. To fully disclose the scope of the invention, and the invention is only defined by the scope of the claims.

The shapes, sizes, ratios, angles, numbers, and the like disclosed in the drawings for describing the embodiments of the present invention are illustrative, and thus the present invention is not limited to those shown in the drawings. Like reference numerals refer to like elements throughout the specification. In the following description of the present invention, detailed description of known related arts will be omitted when it is determined that the gist of the present invention may be unnecessarily blurred.

Where the term "comprises", "comprising", "having", "having", or the like is used herein, other parts may be added as long as "only" is not used. The singular forms of the components may be construed in plural unless otherwise expressly stated.

In interpreting the constituent elements, it is construed to include the error range even if there is no separate description.

In the case of a description of the positional relationship, for example, if the positional relationship between two components is described as 'on', 'on top', 'under', or 'next to' Quot; directly " or " direct " may be interposed between those components that are not used.

The first, second, etc. may be used to distinguish the components, but these components are not limited to the function or structure of the component or the names of components attached to the components.

The following embodiments can be combined or combined with each other partly or entirely, and technically various interlocking and driving are possible. Each embodiment may be feasible independently of one another and may be feasible in conjunction.

The tiled display of the present invention senses deterioration of the display panel or automatically adjusts the brightness of the other display panels based on the measured brightness of the display panel that is most deteriorated based on the measured value. The tiled display of the present invention can be implemented based on an organic light emitting display (OLED display) capable of sensing the deterioration of a display panel to compensate for luminance, but the present invention is not limited thereto.

An active matrix type organic light emitting display device reproduces an input image using an organic light emitting diode (OLED) that emits light to each of subpixels, And the luminous efficiency, luminance, viewing angle, and the like are large. Since the organic light emitting display device can express black gradation in full black, the image can be reproduced at a level superior to the contrast ratio and color gamut.

The pixel circuit of the organic light emitting display includes transistors for driving the OLED which is a light emitting element. The transistors may be implemented as TFTs of a metal oxide semiconductor field effect transistor (MOSFET) structure. The transistor may be implemented with a TFT (thin film transistor) having substantially the same structure as the transistor formed in the pixel array. The transistors may be implemented by one or more of a low temperature polysilicon (LTPS) TFT, an oxide TFT, and an a-Si TFT. 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. Within the transistor, the carriers begin to flow from the source. The drain is an electrode from which the carrier exits from the transistor. The flow of carriers from the transistor flows from the source to the drain. In the case of an n-channel transistor (NMOS), since the carrier is an electron, the source voltage has a voltage lower than the drain voltage so that electrons can flow from the source to the drain. The direction of the current in the n-channel transistor (NMOS) flows from the drain to the source side. In the case of a p-channel transistor (PMOS), since the carrier is a hole, the source voltage is higher than the drain voltage so that holes can flow from the source to the drain. Since the holes flow from the source to the drain in the p-channel transistor (PMOS), 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 the drain may be changed depending on the applied voltage. Therefore, the invention is not limited by the source and the drain of the transistor. In the following description, the source and the drain of the transistor will be referred to as first and second electrodes.

The gate signal of the transistor swings between the gate on voltage and the gate off voltage. The gate-on voltage is set to a voltage at which the transistor is turned-on, and the gate-off voltage is set at a voltage at which the transistor is turned off. In the case of an n-channel transistor (NMOS), the gate-on voltage is a gate high voltage (VGH) and the gate-off voltage is a gate low voltage (VGL) have. In the case of a p-channel transistor (PMOS), the gate-on voltage may be the gate-low voltage (VGL) and the gate-off voltage may be the gate high voltage (VGH).

Various embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the following embodiments, the electroluminescent display device of the present invention will be described focusing on an example in which an external compensation circuit is applied.

Referring to FIGS. 1 and 2, a tiled display according to an embodiment of the present invention includes a plurality of display panels PNL1 to PNL12. The display panels (PNL1 to PNL12) implement a large screen.

The tiled display of the present invention includes an integrated control box (hereinafter referred to as "SET ") 200 and a plurality of control boards 204.

The SET 200 includes a host system, an interface for an external peripheral device to the host system, and a main power supply for generating a main power. The host system converts the pixel data of the input image into the resolution of each of the display panels PNL1 to PNL12 and distributes the converted pixel data to the corresponding control boards 204 in a one-to-one correspondence with the display panels PNL1 to PNL12. The host system integrally manages the control boards 204 of the display panels (PNL1 to PNL12). The host system may compare the deterioration measurements received from the timing controllers mounted on the control boards 204 to select the target brightness as shown in FIG.

The SET 200 is connected to the control boards 204 via a cable. The SET 200 distributes the pixel data of the input image distributed by the host system to the control boards 204. The SET 200 controls the synchronization of the control boards 204 so that the images reproduced in the display panels PNL1 to PNL12 are synchronized.

Each of the control boards 204 controls one display panel and a display panel driver for driving the display panel. For example, the N (N is a natural number) control board is responsible for the N-th display panel PNL (N) and the N-th display panel driver for driving the N-th display panel PNL (N). The N-th control board supplies the pixel data of the input image received from the SET 200 to the N-th display panel driving unit. The N th display panel driver writes the pixel data to the pixels of the N th display panel PNL (N). The N-th display panel driving unit senses the electrical characteristics of each of the pixels of the N-th display panel PNL (N) to sense deterioration of the pixels, and detects degradation of the N-th display panel PNL (N) Calculate the level. Thus, the deterioration measurement values calculated from the display panel driving units are shared between the control boards 204 through the wired / wireless interface, or transmitted to the SET 200 and shared via the SET 200.

Each of the control boards 204 compares the deterioration measurement value of the display panel of its own with the deterioration measurement value of the peripheral display panels and determines the deterioration value of the target display panel based on the target brightness luminance, and compensates the luminance of the pixel data based on the target luminance. The display panel having the largest deterioration measurement value is a display panel having the worst deterioration of pixels among the display panels, and the display panel having the lowest luminance when the same data voltage is applied. The target luminance represents the average luminance of the display panel after deterioration. In order to improve the lifetime of the display panel, the larger the deterioration of the display panel, the lower the target luminance is set. The luminance of the display panels PNL1 to PNL12 is automatically adjusted by the control boards 204 in accordance with the target luminance of the display panel having the largest deterioration. Therefore, the brightness of all the display panels PNL1 to PNL12 is automatically the same even if the display panels PNL1 to PNL12 constituting the tiled display of the present invention are different in deterioration level or there is a crossing of the display panel.

The tiled display according to an embodiment of the present invention includes a first display panel driving unit for driving the first display panel, a second display panel driving unit for driving the pixel data to be written to the pixels of the first display panel based on the result of sensing deterioration of the first display panel A second display panel driver for driving the second display panel, and pixel data to be written to the pixels of the second display panel on the basis of the result of sensing the deterioration of the first display panel, And a second deterioration compensating unit for compensating the second deterioration compensating unit. The deterioration compensating units may be installed in the display panel driving unit, as shown in Figs. The first deterioration compensating unit calculates a first deterioration measurement value representative of a deterioration level of the first display panel and transmits the first deterioration measurement value to the second deterioration compensating unit and the second deterioration compensating unit compares the deterioration level of the second display panel, The measured value is calculated and transmitted to the first deterioration compensating unit. Thus, degradation measurements are shared between degradation compensators.

The first deterioration measurement value is an average value of sensing data obtained from all the subpixels of the first display panel. And the second deterioration measurement value is an average value of the sensing data obtained from all the subpixels of the second display panel. Each of the first and second deterioration compensators defines a maximum luminance of the first and second display panels based on a larger one of the first and second degradation measurements. The larger the deterioration measurement value selected by the first and second deterioration compensation units is, the smaller the target brightness is.

The first deterioration compensating unit compensates the deterioration of the pixels by selecting the compensation value limited by the target luminance and modulating the pixel data to be written to the pixels of the first display panel with the selected compensation value. Likewise, the second deterioration compensating unit compensates the deterioration of the pixels by selecting a compensation value limited by the target luminance and modulating pixel data to be written to the pixels of the second display panel with the selected compensation value. The compensation value may be a gain multiplied by the pixel data. The larger the sensing data, the larger the compensation value. The features of the present invention will be described in detail in the following embodiments.

3 is a block diagram showing a display panel and a display panel driving unit. 4 is a circuit diagram showing the deterioration compensating unit.

3 and 4, a screen AA of an Nth (N is a natural number) display panel PNL (N) includes a pixel array for displaying an input image. The pixel array includes a plurality of data lines 102, a plurality of gate lines 104 intersecting with the data lines 102, a plurality of sensing lines 103 arranged in parallel with the data lines 102, And pixels to be disposed.

Each of the pixels includes a plurality of sub-pixels 101 of different colors for color implementation. The subpixels 101 may be divided into a red subpixel, a green subpixel, and a blue subpixel. Each of the pixels may further include a white subpixel. Each of the subpixels 101 includes a pixel circuit 101A.

The N th display panel driver may include a normal driving mode for displaying an input image on a screen and a sensing mode for sensing electrical characteristics of sub pixels for each subpixel using the deterioration compensator shown in FIG. ). In the normal driving mode, the Nth display panel driving unit supplies pixel data of the input image to the pixels of the Nth display panel PNL (N) under control of a timing controller (hereinafter referred to as " TCON & . In the sensing mode, the display panel driving unit senses the electrical characteristics of the driving device for each subpixel under the control of the TCON 130, and compensates for the deterioration of each of the subpixels by selecting a compensation value according to the sensing result.

The N th display panel driver includes a data driver 110 and a gate driver 120. A multiplexer (hereinafter referred to as a "MUX") 112 disposed between the data driver 110 and the data lines 102 may be disposed in the sensing mode under the control of the TCON 130. The multiplexer And selects the data line 102 and the sensing line 103 connected to the deterioration compensating unit.

The data driver 110 receives the pixel data (digital data) of the input image received from the TCON 130 every frame period using a digital-to-analog converter (DAC) Data) to a gamma compensation voltage to output a data voltage Vdata. The data voltage (Vdata) is applied to the pixels through the MUX 112 and the data line 102. The DAC and the sensing unit 111 of the deterioration compensating unit may be integrated into an IC (integrated circuit) of the data driver 110 as shown in FIG.

The gate driver 120 outputs a gate signal (or a scan signal) to the gate lines 104 under the control of the TCON 130. The gate signal may include, but is not limited to, a first scan signal SCAN1, a second scan signal SCAN2, and a light emission signal EM as shown in FIG. The gate signals SCAN1, SCAN2 and EM are synchronized with the data voltage Vdata output from the data driver 110. [ The gate signals SCAN1, SCAN2 and EM can be generated as pulses swinging between the gate high voltage VGH and the gate low voltage VGL. The transistors of the pixel circuit 101A may be turned on according to the gate high voltage VGH of the gate signals SCAN1, SCAN2 and EM. The gate driver 120 may be implemented as a gate in panel (GIP) circuit formed directly on the bezel region on the display panel 100 together with the TFT array of the screen AA.

The Nth display panel driving unit further includes a display module power unit. The display module power unit receives the main power from the SET 200 and generates the driving power of the Nth display panel driving unit and the analog power of the display panel PNL (N). For example, the power supply of the display module includes a drive power source of the N-th display panel driver and the TCON, a gamma reference voltage, a reference voltage (VPREO), and a gate high voltage (VGH). And a gate low voltage (VGL). The gamma reference voltage is divided by a voltage divider circuit and converted into a gamma compensation voltage corresponding to the gradation voltage of the pixel data and supplied to the data driver 110. [ VPREO is set to a voltage higher than the turn-on voltage of the OLED in order to measure the degradation level of the OLED for each subpixel. VPREO can be set to the same voltage on all pixels. The display module power supply includes a charge pump, a regulator, a buck converter, a boost converter, and the like.

The TCON 130 controls the operation timing of the Nth display panel driving unit in the normal driving mode and the sensing mode. The TCON 130 receives the pixel data of the input image and the timing signal synchronized with the pixel data from the SET 200. The TCON 130 transmits the pixel data of the input image from the SET 200 to the data driver 110. The TCON 130 generates timing control signals for controlling the operation timing of the display panel driving unit using the timing signals received from the SET 200 to control the operation timing of the display panel driving unit.

The TCON 130 may include a compensator 131 of the deterioration compensator shown in FIG.

The deterioration compensating unit senses each of the subpixels of the Nth display panel PNL (N) and compensates pixel data to be written to each of the subpixels based on the sensing result of the subpixels. The degradation compensation unit compares the degradation measurement (DM) of the Nth display panel PNL (N) with the peripheral display panels PNL (N-1) and PNL (N + 1) (DM) determines the target brightness as the deterioration measurement value of the largest display panel. The target luminance defines the maximum luminance of the Nth display panel PNL (N). The larger the deterioration measurement value DM is, the smaller the target luminance is. The maximum luminance is limited in all the pixels of the Nth display panel PNL (N) by the target luminance. The target luminance value is inversely proportional to the degradation measurement (DM) of the display panel in order to prevent a decrease in lifetime due to deterioration of pixels. The target luminance is implemented in a look-up table and stored in a memory connected to the TCON 130.

The Degradation Measure (DM) is a value representative of the deterioration level of the display panel. Is calculated as an average value of sensing data obtained from all the subpixels of the display panel in each of the display panels at the time of sensing the deterioration of the sensing mode. The deterioration measurement value DM is updated at every degradation sensing and stored in a memory connected to the TCON 130. [ The deterioration compensator compensates the deterioration of each of the subpixels by adjusting the gain of the pixel data in each of the subpixels in order to compensate the deterioration level based on the sensing data of the subpixel based on the target luminance selected according to the deterioration measurement value of the display panel . The deterioration compensating unit may be implemented every power ON sequence in which power is generated at the display panel driving unit and at predetermined time intervals within a period in which the image is displayed.

The deterioration compensating section includes a sensing line 103 connected to the pixel circuit 101A in each of the subpixels 101, a sensing section 111 and sensing data (digital data) from the sensing section 111, And a compensating unit 131 for receiving the signal. The compensation unit 131 may be embedded in the TCON 130. [

The memory connected to the TCON 130 stores the OLED sensing value at the time of shipment of the product, that is, before the deterioration progresses, in each of the subpixels. The sensing unit 111 senses the voltage of the OLED in each of the subpixels through the sensing line 103 at the time of sensing the deterioration of the sensing mode and outputs the sensed voltage to an analog-to-digital converter And converts the sensed value of the OLED into sensing data (digital data) and transmits it to the compensating unit 131. [ The compensation unit 131 may compare the sensing value of the OLED with the initial sensing value before deterioration to determine the deterioration degree of the OLED in each of the subpixels. As the deterioration progresses much more, the sensing voltage of the OLED increases. Therefore, as the sensing data of the OLED increases, the deterioration of the OLED increases, so that the compensation value of the pixel data, that is, the gain is determined to be a larger value.

The compensating unit 131 calculates the deterioration measurement value DM of the N th display panel PNL (N) based on the result of sensing by the subpixels, (N-1) and PNL (N + 1) with the degradation measurement values DM of the Nth display panel PNL (N). The compensation unit 131 selects the target luminance corresponding to the largest deterioration measurement value DM. The compensating unit 131 compensates the luminance of the pixel data by limiting the gain so that the luminance of the pixel over the selected target luminance is not increased.

5A and 5B are circuit diagrams showing details of an example of a pixel circuit and a deterioration compensating unit.

5A and 5B, the pixel circuit 101A is supplied with a pixel driving voltage (hereinafter referred to as "VDD") and a low potential power source voltage (hereinafter referred to as "VSS"). VPREO for turning on the OLED is supplied to the pixel circuit 101A at the time of deterioration sensing in the sensing mode.

The pixel circuit 101A includes an OLED, a plurality of transistors T1 to T5, DT, and a capacitor Cst. The transistors T1 to T5, DT may be implemented as p-channel transistors (PMOS).

The OLED emits light with a current generated in accordance with the gate-source voltage Vgs of the driving transistor DT which varies depending on the data voltage Vdata. The OLED includes an organic compound layer formed between the anode and the cathode. The organic compound layer includes a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL), an electron injection layer EIL), and the like. The anode of the OLED is connected to the fourth and fifth transistors T4 and T5 and the cathode of the OLED is connected to the VSS node to which a low potential power supply voltage (hereinafter referred to as " VSS ") is applied.

The first transistor T1 is turned on according to the first scan signal SCAN1 to connect the data line 102 to the first electrode of the capacitor Cst to supply the data voltage Vdata to the capacitor Cst . The first transistor T1 is connected to the gate of the first gate line 1041 to which the first scan signal SCAN1 is applied, the first electrode connected to the data line 102 and the first electrode of the capacitor Cst And a second electrode.

The second transistor T2 is turned on according to the second scan signal SCAN2 to connect the gate of the driving transistor DT to the second electrode. The second transistor T2 has a gate connected to the second gate line 1042 to which the second scan signal SCAN2 is applied, a second electrode connected to the node between the second electrode of the capacitor Cst and the gate of the driving transistor DT And a second electrode connected to a node between the second electrode of the second driving transistor DT and the first electrode of the fourth transistor T4.

The third and fourth transistors T3 and T4 are turned on in the normal drive mode to form a current path between the VDD and the OLED while maintaining the off state in the sensing mode. The third transistor T3 is turned on according to the emission signal EM to connect the node between the first electrode of the first transistor T1 and the first electrode of the capacitor Cst to the sensing line 103. [ The third transistor T1 is connected to the node between the first electrode of the first transistor T1 and the first electrode of the capacitor Cst connected to the third gate line 1043 to which the emission signal EM is applied A first electrode, and a second electrode coupled to the sensing line 103.

The fourth transistor T4 is turned on according to the emission signal EM to connect the node between the second electrode of the driving transistor DT and the second electrode of the second transistor T2 to the anode of the OLED. The fourth transistor T4 has a gate connected to the third gate line 1043, a first electrode connected to a node between the second electrode of the driving transistor DT and the second electrode of the second transistor T2, And a second electrode connected to a node between the anode and the second electrode of the fifth transistor T5.

The fifth transistor T5 is turned on according to the second scan signal SCAN2 to connect the sensing line 103 to the anode of the OLED. The fifth transistor T5 includes a gate coupled to the second gate line 1042, a first electrode coupled to the sensing line 103, and a second transistor coupled to the node between the anode of the OLED and the second electrode of the fourth transistor T4. Two electrodes.

The driving transistor DT supplies current to the OLED in accordance with the gate-source voltage Vgs. The driving transistor DT has a gate connected to the node between the first electrode of the capacitor Cst and the first electrode of the second transistor T2, a second electrode connected to the VDD line to which VDD is applied, And a second electrode connected to a node between the second electrode of the fourth transistor T4 and the first electrode of the fourth transistor T4.

The sensing mode deterioration sensing method includes an OLED light emission step and an OLED voltage sensing step. The sensing unit 111 operates in the sensing mode.

The sensing unit 111 includes first to third switch elements SCS, PRE, SEN, a capacitor Cs, and an ADC. The first switch (SCS) is used when it is sensed separately for each color of subpixels. When the OLED deterioration of the red subpixels is sensed, the first switch SCS connected to the red subpixels is turned on in the OLED emission step, while the first switch SCS connected to the subpixels of other colors other than red Is turned off in the OLED emission step. When the OLED deterioration of the green subpixels is sensed, the first switch SCS connected to the green subpixels is turned on in the OLED emission step, while the first switch SCS connected to the subpixels of other colors other than green Is turned off in the OLED emission step. When the OLED deterioration of blue subpixels is sensed, a first switch (SCS) connected to the blue subpixels is turned on in the OLED emission step, while a first switch (SCS) connected to subpixels of other colors other than blue Is turned off in the OLED emission step. All the first switches SCS are turned off in the OLED voltage sensing step.

The second switch PRE is turned on in the OLED light emission stage to supply VPREO to the OLED. The second switch PRE is turned off in the OLED voltage sensing step.

The third switch SEN is turned off in the OLED light emission step. The third switch SEN is turned on in the OLED voltage sensing step to charge the capacitor Cs with the voltage of the capacitor Cps of the sensing line 103. [ In the sensing step, the ADC converts the voltage of the capacitor Cs, that is, the voltage of the OLED, into digital data to output sensing data.

The multiplexer 112 includes a first transistor M1 for connecting the sensing unit 111 to the sensing line 103 and a second transistor M2 for connecting the sensing unit 111 to the data line 102 . The first transistor M1 is turned on according to the first MUX signal SMUX to connect the sensing unit 111 to the sensing line 103. [ The second transistor M2 is turned on according to the second MUX signal DMUX to connect the sensing unit 111 to the data line 102. [

5A shows a current path of the sensing unit 111 and the pixel circuit 101A in the OLED light emission step of the sensing mode. 5B shows the current paths of the sensing unit 111 and the pixel circuit 101A in the sensing step of the sensing mode. In the OLED emission step, VPEO is applied to the anode of the OLED so that the OLED is turned on. At this time, current flows through the OLED. If the OLED is not deteriorated, the amount of current flowing through the OLED in the OLED emission step is large, so that the charge charged in the capacitor (Cps) of the sensing line 103 is small. On the other hand, when the OLED is deteriorated, the resistance of the OLED increases, and the amount of current flowing through the OLED between the surfaces VPRE and VSS in the OLED light emission step is reduced and the charge amount of the capacitor Cps of the sensing line 103 is increased Loses. Therefore, as the deterioration of the OLED increases, the voltage of the capacitor Cps increases. The capacitor Cs of the sensing unit 111 is charged with the voltage charged in the capacitor Cps of the sensing line 103 in the sensing step. The larger the deterioration of the OLED, the larger the voltage of the capacitor Cs becomes. Therefore, the larger the deterioration of the OLED, the larger the sensing data obtained through the ADC.

6 is a block diagram showing the compensation unit 131 in detail. 7 is a diagram showing a look-up table (LUT1). 8 is a diagram showing a luminance lookup table (LUT2).

6, the compensation unit 131 includes a target brightness determination unit 72, and a pixel data compensation unit 74. [

The pixel data compensating section 74 receives the target luminance of the luminance lookup table LUT1 and the sensing data from the sensing section 111 from the target luminance determining section 72. [ The pixel data compensating unit 74 determines whether to compensate the pixel data for each subpixel based on the sensing data for each subpixel. In order to compensate the pixel data, the pixel data compensator 74 inputs the sensing data to the compensation lookup table LUT2, multiplies the pixel data by the gain Gain output from the compensation lookup table LUT2, Lt; / RTI > 6, "DATA" is pixel data before compensation, and "DATA '" is pixel data after compensation output from the pixel data compensator 74. After the compensation, the pixel data (DATA ') is transferred to the data driver 110.

The pixel data compensation section 74 selects the gain curve of the compensation lookup table LUT2 according to the luminance lookup table LUT1 selected by the target luminance determination section 72 and compensates the pixel data with the selected gain curve. As shown in FIG. 7, the compensation lookup table LUT2 is set to a gain curve such that the gain increases as the sensing data increases. As described above, as the deterioration of the OLED increases, the sensing data has a large value. The gain of the compensation look-up table LUT2 is limited according to the target luminances TL1 and TL2 as shown in Fig. The lower the target luminance, the lower the maximum gain value. For example, when the target luminance is TL2, the maximum gain value is lower than the maximum gain value when the target luminance is TL1. Therefore, the compensation look-up table LUT2 is set to a plurality of gain curves with different maximum gain values according to the target luminance.

On the other hand, the target luminance at the time of shipment of the product is stored in the memory as a default value. When the deterioration measurement value DM is calculated based on the deterioration sensing result in the first frame period after the product is shipped, the target luminance is updated by the deterioration measurement value DM, and the target luminance Is updated in real time. The target luminance stored in the memory in the power off sequence is read in the next power on sequence.

The pixel data compensator 74 compares the deterioration measurement value DM (N) with respect to the Nth display panel PNL (N) as an average value of sensing data for all the subpixels of the Nth display panel PNL (N) ). The deterioration measurement value DM (N) of the Nth display panel PNL (N) represents the average brightness after deterioration of the Nth display panel PNL (N).

The target brightness determination section 72 determines the deterioration measurement values DA (N-1) and DM (N + 1) indicating the average brightness after deterioration of the peripheral display panels PNL (N-1) and PNL And the deterioration measurement value PNL (N) for the Nth display panel PNL (N) from the pixel data compensating section 74. The target brightness determining section 72 compares the deterioration measurement values DM (N) (N-1), DM (N), DM (N + 1)) to select the largest deterioration measurement value DM. The target brightness determination section 72 determines the largest deterioration measurement value DM And the target luminance is selected by inputting to the luminance lookup table LUT 1. The luminance lookup table LUT1 is set to the target luminance having an inversely proportional relationship with the luminance measurement value DM as shown in Figure 8. As described above , And the luminance measurement value DM indicates the average luminance after deterioration of the display panel, the display panel deteriorates more severely as the luminance measurement value DM is larger. In order to prevent the deterioration of the life of the display panel, Hui The maximum luminance of the pixel data compensated by the pixel data compensator 74 is limited by the target luminance. The luminance is determined in the target brightness determination section 72 based on the comparison result of the deterioration measurement values of the display panels PNL (N-1), PNL (N), and PNL (N + 1) as described above.

The compensation unit 131 may be disposed in the TCON 130 of each of the display panels. Therefore, as shown in FIG. 9, the degradation measurement values DM (N-1), DM (N), and DM (N) between the TCONs TCON DM (N + 1) are shared. The TCONs TCON (N-1), TCON (N), and TCON (N + 1) may be implemented in a 1: 1 manner on the control board 204 shown in FIG. For example, the N-th TCON (TCON (N)) is mounted on the N-th control board 204 corresponding to the N-th display panel PNL (N).

FIG. 10 is a diagram showing an example in which the deterioration measurement values of the display panels in the SET 200 of the tiled display are compared and the target luminance is selected.

10, TCONs (TCON (N-1), TCON (N), and TCON (N + 1)) mounted on the control boards 204 are connected to deterioration measurement values DM (N) and DM (N + 1), and transmits the calculated data to the SET 200. The SET 200 compares the deterioration measurement values DM (N-1), DM (N), and DM (N + 1) received from the control boards 204, The target luminance indicated by the deterioration measurement value is selected. The SET 200 transmits the selected target brightness according to the deterioration measurement value to the TCONs TCON (N-1), TCON (N), and TCON (N + 1) of the control boards 204. In this embodiment, the luminance lookup table LUT1 is stored in the memory of the SET 200, and the memory of the control boards 204 does not need to store the luminance lookup table LUT1.

11 is a diagram illustrating an example in which the degradation measurement values are compared in each of the timing controllers mounted on the control boards of the tiled display to select the target brightness.

11, the deterioration measurement value is calculated in each of the TCONs (TCON (N-1), TCON (N), and TCON (N + 1)) mounted on the control boards 204 and transmitted to the other TCON (N-1), DM (N), and DM (N + 1) in each of the TCONs TCON (N-1), TCON And the target luminance corresponding to the largest deterioration measurement value is selected. This embodiment requires that the luminance lookup table LUT1 be stored in the memory of the control boards 204 together with the compensation lookup table LUT2. Since this embodiment does not need to support the target brightness selecting function in the SET 200, it can be implemented in the existing SET board.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or 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.

72: target luminance determining section 74: pixel data compensating section
110: Data driver 111:
120: Gate driver 131:
130, TCON, TCON (N-1), TCON (N), TCON (N +
200: Integrated control box (SET) 202: Cable
204: Control board DM: Deterioration measurement value
PNL1 to PNL12, PNL (N-1), PNL (N), and PNL (N +

Claims (9)

A first display panel driver driving the first display panel;
A first deterioration compensating unit compensating pixel data to be written to the pixels of the first display panel based on a result of sensing deterioration of the first display panel;
A second display panel driver driving the second display panel; And
And a second deterioration compensating unit compensating for pixel data to be written to the pixels of the second display panel based on a result of sensing deterioration of the first display panel,
Wherein the first deterioration compensating unit calculates a first deterioration measurement value representative of a deterioration level of the first display panel and transmits the first deterioration measurement value to the second deterioration compensating unit,
Wherein the second deterioration compensating unit calculates a second deterioration measurement value representing the deterioration level of the second display panel and transmits the second deterioration measurement value to the first deterioration compensating unit. The method according to claim 1,
Wherein the first deterioration measurement value is an average value of sensing data obtained from all the subpixels of the first display panel,
Wherein the second deterioration measurement value is an average value of sensing data obtained from all the subpixels of the second display panel. The method according to claim 1,
Wherein each of the first and second deterioration compensating units selects a target luminance that defines a maximum luminance of the first and second display panels based on a larger deterioration measurement value among the first and second deterioration measurement values Idle display. 3. The method of claim 2,
Wherein the target luminance is reduced as the deterioration measurement value selected by the first and second deterioration compensation units is larger. 3. The method of claim 2,
Wherein the first deterioration compensator selects a first compensation value limited by the target luminance and modulates pixel data to be written to the pixels of the first display panel with the selected first compensation value, Lt; / RTI >
Wherein the second deterioration compensator selects a second compensation value that is limited by the target luminance and modulates pixel data to be written to the pixels of the second display panel with the selected second compensation value, Lt; / RTI > display. 6. The method of claim 5,
Wherein the maximum value of the first and second compensation values is limited by the target luminance. The method according to claim 6,
Wherein the first and second compensation values become larger as the sensing data is larger. Calculating a first deterioration measurement value representing a deterioration level of the first display panel based on a result of sensing deterioration of the first display panel;
Calculating a second deterioration measurement value representing a deterioration level of the second display panel based on a result of sensing deterioration of the second display panel;
Selecting a larger deterioration measurement value among the first and second deterioration measurement values; And
And selecting a target luminance that defines a maximum luminance of the first and second display panels according to the selected degradation measurement value. 9. The method of claim 8,
Selecting a first compensation value limited by the target luminance and compensating for pixel deterioration of the first display panel by modulating pixel data to be written to pixels of the first display panel with the selected first compensation value; And
And compensating pixel deterioration of the second display panel by modulating pixel data to be written to the pixels of the second display panel with the selected second compensation value by selecting a second compensation value limited by the target luminance Lt; RTI ID = 0.0 > a < / RTI > tiled display.

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